thunderbolt: Fix NULL dereference in tb_remove_work()grafted

There is a slight race between tb_remove_work() and tb_domain_remove()
which leads to dereferencing a NULL tb->root_switch pointer inside
tb_free_unplugged_xdomains():

        Thread A                            Thread B

  tb_remove_work()
                                    tb_domain_remove()
                                      mutex_lock(&tb->lock)
                                      tb_stop()
                                        /* doesn't cancel a running callback */
                                        cancel_delayed_work(&tcm->remove_work)
                                        ...
                                        tb_switch_remove(tb->root_switch)
                                        tb->root_switch = NULL
                                      mutex_unlock(&tb->lock)
    mutex_lock(&tb->lock)
    ...
    /* without checking ->root_switch */
    tb_free_unplugged_xdomains(tb->root_switch)
    mutex_unlock(&tb->lock)

Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without
holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains()
out of the &tb->lock section and the check for tb->root_switch, in
particular.  It states:

  For this reason separate removing the XDomain from the topology data
  structures (where we need the lock) from unregistering the device from
  the bus (where remove callbacks of the drivers are being called).

tb_free_unplugged_xdomains() belongs to the former group of functions
requiring the lock.  And it also calls tb_xdomain_remove() which should
only be called with &tb->lock held.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

185 files changed, 71244 insertions, 0 deletions

diff --git a/tools/lib/api/Build b/tools/lib/api/Build
new file mode 100644
index 000000000..6e2373db5
--- /dev/null
+++ b/tools/lib/api/Build
@@ -0,0 +1,9 @@
+libapi-y += fd/
+libapi-y += fs/
+libapi-y += cpu.o
+libapi-y += debug.o
+libapi-y += str_error_r.o
+
+$(OUTPUT)str_error_r.o: ../str_error_r.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
diff --git a/tools/lib/api/Makefile b/tools/lib/api/Makefile
new file mode 100644
index 000000000..a228fdb5a
--- /dev/null
+++ b/tools/lib/api/Makefile
@@ -0,0 +1,125 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../../scripts/Makefile.include
+include ../../scripts/utilities.mak		# QUIET_CLEAN
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+MAKEFLAGS += --no-print-directory
+
+INSTALL = install
+
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+LIBFILE = $(OUTPUT)libapi.a
+
+CFLAGS := $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
+CFLAGS += -ggdb3 -Wall -Wextra -std=gnu99 -U_FORTIFY_SOURCE -fPIC
+
+ifeq ($(DEBUG),0)
+  CFLAGS += -O3
+endif
+
+ifeq ($(DEBUG),0)
+  CFLAGS += -D_FORTIFY_SOURCE
+endif
+
+# Treat warnings as errors unless directed not to
+ifneq ($(WERROR),0)
+  CFLAGS += -Werror
+endif
+
+CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
+CFLAGS += -I$(srctree)/tools/lib/api
+CFLAGS += -I$(srctree)/tools/include
+
+RM = rm -f
+
+API_IN := $(OUTPUT)libapi-in.o
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?=
+libdir = $(prefix)/$(libdir_relative)
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+include $(srctree)/tools/build/Makefile.include
+include $(srctree)/tools/scripts/Makefile.include
+
+all: fixdep $(LIBFILE)
+
+$(API_IN): FORCE
+	@$(MAKE) $(build)=libapi
+
+$(LIBFILE): $(API_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(API_IN)
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
+	fi
+endef
+
+define do_install
+	if [ ! -d '$2' ]; then             \
+		$(INSTALL) -d -m 755 '$2'; \
+	fi;                                \
+	$(INSTALL) $1 $(if $3,-m $3,) '$2'
+endef
+
+install_lib: $(LIBFILE)
+	$(call QUIET_INSTALL, $(LIBFILE)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fpR $(LIBFILE) $(DESTDIR)$(libdir_SQ)
+
+HDRS := cpu.h debug.h io.h io_dir.h
+FD_HDRS := fd/array.h
+FS_HDRS := fs/fs.h fs/tracing_path.h
+INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/api
+INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))
+INSTALL_FD_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(FD_HDRS))
+INSTALL_FS_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(FS_HDRS))
+
+$(INSTALL_HDRS): $(INSTALL_HDRS_PFX)/%.h: %.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/,644)
+
+$(INSTALL_FD_HDRS): $(INSTALL_HDRS_PFX)/fd/%.h: fd/%.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/fd/,644)
+
+$(INSTALL_FS_HDRS): $(INSTALL_HDRS_PFX)/fs/%.h: fs/%.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/fs/,644)
+
+install_headers: $(INSTALL_HDRS) $(INSTALL_FD_HDRS) $(INSTALL_FS_HDRS)
+	$(call QUIET_INSTALL, libapi_headers)
+
+install: install_lib install_headers
+
+clean:
+	$(call QUIET_CLEAN, libapi) $(RM) $(LIBFILE); \
+	find $(or $(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+
+FORCE:
+
+.PHONY: clean FORCE
diff --git a/tools/lib/api/cpu.c b/tools/lib/api/cpu.c
new file mode 100644
index 000000000..4af6d4b7a
--- /dev/null
+++ b/tools/lib/api/cpu.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+
+#include "cpu.h"
+#include "fs/fs.h"
+
+int cpu__get_max_freq(unsigned long long *freq)
+{
+	char entry[PATH_MAX];
+	int cpu;
+
+	if (sysfs__read_int("devices/system/cpu/online", &cpu) < 0)
+		return -1;
+
+	snprintf(entry, sizeof(entry),
+		 "devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", cpu);
+
+	return sysfs__read_ull(entry, freq);
+}
diff --git a/tools/lib/api/cpu.h b/tools/lib/api/cpu.h
new file mode 100644
index 000000000..90a102fb2
--- /dev/null
+++ b/tools/lib/api/cpu.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_CPU__
+#define __API_CPU__
+
+int cpu__get_max_freq(unsigned long long *freq);
+
+#endif /* __API_CPU__ */
diff --git a/tools/lib/api/debug-internal.h b/tools/lib/api/debug-internal.h
new file mode 100644
index 000000000..5a5820c11
--- /dev/null
+++ b/tools/lib/api/debug-internal.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_DEBUG_INTERNAL_H__
+#define __API_DEBUG_INTERNAL_H__
+
+#include "debug.h"
+
+#define __pr(func, fmt, ...)	\
+do {				\
+	if ((func))		\
+		(func)("libapi: " fmt, ##__VA_ARGS__); \
+} while (0)
+
+extern libapi_print_fn_t __pr_warn;
+extern libapi_print_fn_t __pr_info;
+extern libapi_print_fn_t __pr_debug;
+
+#define pr_warn(fmt, ...)	__pr(__pr_warn, fmt, ##__VA_ARGS__)
+#define pr_info(fmt, ...)	__pr(__pr_info, fmt, ##__VA_ARGS__)
+#define pr_debug(fmt, ...)	__pr(__pr_debug, fmt, ##__VA_ARGS__)
+
+#endif /* __API_DEBUG_INTERNAL_H__ */
diff --git a/tools/lib/api/debug.c b/tools/lib/api/debug.c
new file mode 100644
index 000000000..7708f0558
--- /dev/null
+++ b/tools/lib/api/debug.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdarg.h>
+#include "debug.h"
+#include "debug-internal.h"
+
+static int __base_pr(const char *format, ...)
+{
+	va_list args;
+	int err;
+
+	va_start(args, format);
+	err = vfprintf(stderr, format, args);
+	va_end(args);
+	return err;
+}
+
+libapi_print_fn_t __pr_warn    = __base_pr;
+libapi_print_fn_t __pr_info    = __base_pr;
+libapi_print_fn_t __pr_debug;
+
+void libapi_set_print(libapi_print_fn_t warn,
+		      libapi_print_fn_t info,
+		      libapi_print_fn_t debug)
+{
+	__pr_warn    = warn;
+	__pr_info    = info;
+	__pr_debug   = debug;
+}
diff --git a/tools/lib/api/debug.h b/tools/lib/api/debug.h
new file mode 100644
index 000000000..3684dd6e0
--- /dev/null
+++ b/tools/lib/api/debug.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_DEBUG_H__
+#define __API_DEBUG_H__
+
+typedef int (*libapi_print_fn_t)(const char *, ...);
+
+void libapi_set_print(libapi_print_fn_t warn,
+		      libapi_print_fn_t info,
+		      libapi_print_fn_t debug);
+
+#endif /* __API_DEBUG_H__ */
diff --git a/tools/lib/api/fd/Build b/tools/lib/api/fd/Build
new file mode 100644
index 000000000..605d99f6d
--- /dev/null
+++ b/tools/lib/api/fd/Build
@@ -0,0 +1 @@
+libapi-y += array.o
diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
new file mode 100644
index 000000000..67b73481d
--- /dev/null
+++ b/tools/lib/api/fd/array.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2014, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+ */
+#include "array.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+void fdarray__init(struct fdarray *fda, int nr_autogrow)
+{
+	fda->entries	 = NULL;
+	fda->priv	 = NULL;
+	fda->nr		 = fda->nr_alloc = 0;
+	fda->nr_autogrow = nr_autogrow;
+}
+
+int fdarray__grow(struct fdarray *fda, int nr)
+{
+	struct priv *priv;
+	int nr_alloc = fda->nr_alloc + nr;
+	size_t psize = sizeof(fda->priv[0]) * nr_alloc;
+	size_t size  = sizeof(struct pollfd) * nr_alloc;
+	struct pollfd *entries = realloc(fda->entries, size);
+
+	if (entries == NULL)
+		return -ENOMEM;
+
+	priv = realloc(fda->priv, psize);
+	if (priv == NULL) {
+		/* this will be freed by fdarray__exit() */
+		fda->entries = entries;
+		return -ENOMEM;
+	}
+
+	memset(&entries[fda->nr_alloc], 0, sizeof(struct pollfd) * nr);
+	memset(&priv[fda->nr_alloc], 0, sizeof(fda->priv[0]) * nr);
+
+	fda->nr_alloc = nr_alloc;
+	fda->entries  = entries;
+	fda->priv     = priv;
+	return 0;
+}
+
+struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow)
+{
+	struct fdarray *fda = calloc(1, sizeof(*fda));
+
+	if (fda != NULL) {
+		if (fdarray__grow(fda, nr_alloc)) {
+			fdarray__delete(fda);
+			fda = NULL;
+		} else {
+			fda->nr_autogrow = nr_autogrow;
+		}
+	}
+
+	return fda;
+}
+
+void fdarray__exit(struct fdarray *fda)
+{
+	free(fda->entries);
+	free(fda->priv);
+	fdarray__init(fda, 0);
+}
+
+void fdarray__delete(struct fdarray *fda)
+{
+	fdarray__exit(fda);
+	free(fda);
+}
+
+int fdarray__add(struct fdarray *fda, int fd, short revents, enum fdarray_flags flags)
+{
+	int pos = fda->nr;
+
+	if (fda->nr == fda->nr_alloc &&
+	    fdarray__grow(fda, fda->nr_autogrow) < 0)
+		return -ENOMEM;
+
+	fda->entries[fda->nr].fd     = fd;
+	fda->entries[fda->nr].events = revents;
+	fda->priv[fda->nr].flags = flags;
+	fda->nr++;
+	return pos;
+}
+
+int fdarray__dup_entry_from(struct fdarray *fda, int pos, struct fdarray *from)
+{
+	struct pollfd *entry;
+	int npos;
+
+	if (pos >= from->nr)
+		return -EINVAL;
+
+	entry = &from->entries[pos];
+
+	npos = fdarray__add(fda, entry->fd, entry->events, from->priv[pos].flags);
+	if (npos >= 0)
+		fda->priv[npos] = from->priv[pos];
+
+	return npos;
+}
+
+int fdarray__filter(struct fdarray *fda, short revents,
+		    void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
+		    void *arg)
+{
+	int fd, nr = 0;
+
+	if (fda->nr == 0)
+		return 0;
+
+	for (fd = 0; fd < fda->nr; ++fd) {
+		if (fda->priv[fd].flags & fdarray_flag__nonfilterable)
+			continue;
+
+		if (!fda->entries[fd].events)
+			continue;
+
+		if (fda->entries[fd].revents & revents) {
+			if (entry_destructor)
+				entry_destructor(fda, fd, arg);
+
+			/*
+			 * Set fd to -1 so poll() ignores this entry; otherwise
+			 * POLLHUP/POLLERR are still reported for events=0 fds
+			 * (POSIX: always checked), causing a poll storm.
+			 */
+			fda->entries[fd].fd = -1;
+			fda->entries[fd].revents = fda->entries[fd].events = 0;
+			continue;
+		}
+
+		++nr;
+	}
+
+	return nr;
+}
+
+int fdarray__poll(struct fdarray *fda, int timeout)
+{
+	return poll(fda->entries, fda->nr, timeout);
+}
+
+int fdarray__fprintf(struct fdarray *fda, FILE *fp)
+{
+	int fd, printed = fprintf(fp, "%d [ ", fda->nr);
+
+	for (fd = 0; fd < fda->nr; ++fd)
+		printed += fprintf(fp, "%s%d", fd ? ", " : "", fda->entries[fd].fd);
+
+	return printed + fprintf(fp, " ]");
+}
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
new file mode 100644
index 000000000..5c01f7b05
--- /dev/null
+++ b/tools/lib/api/fd/array.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_FD_ARRAY__
+#define __API_FD_ARRAY__
+
+#include <stdio.h>
+
+struct pollfd;
+
+/**
+ * struct fdarray: Array of file descriptors
+ *
+ * @priv: Per array entry priv area, users should access just its contents,
+ *	  not set it to anything, as it is kept in synch with @entries, being
+ *	  realloc'ed, * for instance, in fdarray__{grow,filter}.
+ *
+ *	  I.e. using 'fda->priv[N].idx = * value' where N < fda->nr is ok,
+ *	  but doing 'fda->priv = malloc(M)' is not allowed.
+ */
+struct fdarray {
+	int	       nr;
+	int	       nr_alloc;
+	int	       nr_autogrow;
+	struct pollfd *entries;
+	struct priv {
+		union {
+			int    idx;
+			void   *ptr;
+		};
+		unsigned int flags;
+	} *priv;
+};
+
+enum fdarray_flags {
+	fdarray_flag__default		= 0x00000000,
+	fdarray_flag__nonfilterable	= 0x00000001,
+	fdarray_flag__non_perf_event	= 0x00000002,
+};
+
+void fdarray__init(struct fdarray *fda, int nr_autogrow);
+void fdarray__exit(struct fdarray *fda);
+
+struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow);
+void fdarray__delete(struct fdarray *fda);
+
+int fdarray__add(struct fdarray *fda, int fd, short revents, enum fdarray_flags flags);
+int fdarray__dup_entry_from(struct fdarray *fda, int pos, struct fdarray *from);
+int fdarray__poll(struct fdarray *fda, int timeout);
+int fdarray__filter(struct fdarray *fda, short revents,
+		    void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
+		    void *arg);
+int fdarray__grow(struct fdarray *fda, int extra);
+int fdarray__fprintf(struct fdarray *fda, FILE *fp);
+
+static inline int fdarray__available_entries(struct fdarray *fda)
+{
+	return fda->nr_alloc - fda->nr;
+}
+
+#endif /* __API_FD_ARRAY__ */
diff --git a/tools/lib/api/fs/Build b/tools/lib/api/fs/Build
new file mode 100644
index 000000000..0f75b2865
--- /dev/null
+++ b/tools/lib/api/fs/Build
@@ -0,0 +1,3 @@
+libapi-y += fs.o
+libapi-y += tracing_path.o
+libapi-y += cgroup.o
diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c
new file mode 100644
index 000000000..250629a09
--- /dev/null
+++ b/tools/lib/api/fs/cgroup.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/stringify.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "fs.h"
+
+struct cgroupfs_cache_entry {
+	char	subsys[32];
+	char	mountpoint[PATH_MAX];
+};
+
+/* just cache last used one */
+static struct cgroupfs_cache_entry *cached;
+
+int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys)
+{
+	FILE *fp;
+	char *line = NULL;
+	size_t len = 0;
+	char *p, *path;
+	char mountpoint[PATH_MAX];
+
+	if (cached && !strcmp(cached->subsys, subsys)) {
+		if (strlen(cached->mountpoint) < maxlen) {
+			strcpy(buf, cached->mountpoint);
+			return 0;
+		}
+		return -1;
+	}
+
+	fp = fopen("/proc/mounts", "r");
+	if (!fp)
+		return -1;
+
+	/*
+	 * in order to handle split hierarchy, we need to scan /proc/mounts
+	 * and inspect every cgroupfs mount point to find one that has
+	 * the given subsystem.  If we found v1, just use it.  If not we can
+	 * use v2 path as a fallback.
+	 */
+	mountpoint[0] = '\0';
+
+	/*
+	 * The /proc/mounts has the follow format:
+	 *
+	 *   <devname> <mount point> <fs type> <options> ...
+	 *
+	 */
+	while (getline(&line, &len, fp) != -1) {
+		/* skip devname */
+		p = strchr(line, ' ');
+		if (p == NULL)
+			continue;
+
+		/* save the mount point */
+		path = ++p;
+		p = strchr(p, ' ');
+		if (p == NULL)
+			continue;
+
+		*p++ = '\0';
+
+		/* check filesystem type */
+		if (strncmp(p, "cgroup", 6))
+			continue;
+
+		if (p[6] == '2') {
+			/* save cgroup v2 path */
+			strcpy(mountpoint, path);
+			continue;
+		}
+
+		/* now we have cgroup v1, check the options for subsystem */
+		p += 7;
+
+		p = strstr(p, subsys);
+		if (p == NULL)
+			continue;
+
+		/* sanity check: it should be separated by a space or a comma */
+		if (!strchr(" ,", p[-1]) || !strchr(" ,", p[strlen(subsys)]))
+			continue;
+
+		strcpy(mountpoint, path);
+		break;
+	}
+	free(line);
+	fclose(fp);
+
+	if (!cached)
+		cached = calloc(1, sizeof(*cached));
+
+	if (cached) {
+		strncpy(cached->subsys, subsys, sizeof(cached->subsys) - 1);
+		strcpy(cached->mountpoint, mountpoint);
+	}
+
+	if (mountpoint[0] && strlen(mountpoint) < maxlen) {
+		strcpy(buf, mountpoint);
+		return 0;
+	}
+	return -1;
+}
diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
new file mode 100644
index 000000000..cbd8eab0d
--- /dev/null
+++ b/tools/lib/api/fs/fs.c
@@ -0,0 +1,515 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/vfs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/mount.h>
+
+#include "fs.h"
+#include "../io.h"
+#include "debug-internal.h"
+
+#define _STR(x) #x
+#define STR(x) _STR(x)
+
+#ifndef SYSFS_MAGIC
+#define SYSFS_MAGIC            0x62656572
+#endif
+
+#ifndef PROC_SUPER_MAGIC
+#define PROC_SUPER_MAGIC       0x9fa0
+#endif
+
+#ifndef DEBUGFS_MAGIC
+#define DEBUGFS_MAGIC          0x64626720
+#endif
+
+#ifndef TRACEFS_MAGIC
+#define TRACEFS_MAGIC          0x74726163
+#endif
+
+#ifndef HUGETLBFS_MAGIC
+#define HUGETLBFS_MAGIC        0x958458f6
+#endif
+
+#ifndef BPF_FS_MAGIC
+#define BPF_FS_MAGIC           0xcafe4a11
+#endif
+
+static const char * const sysfs__known_mountpoints[] = {
+	"/sys",
+	0,
+};
+
+static const char * const procfs__known_mountpoints[] = {
+	"/proc",
+	0,
+};
+
+#ifndef DEBUGFS_DEFAULT_PATH
+#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
+#endif
+
+static const char * const debugfs__known_mountpoints[] = {
+	DEBUGFS_DEFAULT_PATH,
+	"/debug",
+	0,
+};
+
+
+#ifndef TRACEFS_DEFAULT_PATH
+#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
+#endif
+
+static const char * const tracefs__known_mountpoints[] = {
+	TRACEFS_DEFAULT_PATH,
+	"/sys/kernel/debug/tracing",
+	"/tracing",
+	"/trace",
+	0,
+};
+
+static const char * const hugetlbfs__known_mountpoints[] = {
+	0,
+};
+
+static const char * const bpf_fs__known_mountpoints[] = {
+	"/sys/fs/bpf",
+	0,
+};
+
+struct fs {
+	const char *		 const name;
+	const char * const *	 const mounts;
+	char			*path;
+	pthread_mutex_t		 mount_mutex;
+	const long		 magic;
+};
+
+#ifndef TRACEFS_MAGIC
+#define TRACEFS_MAGIC 0x74726163
+#endif
+
+static void fs__init_once(struct fs *fs);
+static const char *fs__mountpoint(const struct fs *fs);
+static const char *fs__mount(struct fs *fs);
+
+#define FS(lower_name, fs_name, upper_name)		\
+static struct fs fs__##lower_name = {			\
+	.name = #fs_name,				\
+	.mounts = lower_name##__known_mountpoints,	\
+	.magic = upper_name##_MAGIC,			\
+	.mount_mutex = PTHREAD_MUTEX_INITIALIZER,	\
+};							\
+							\
+static void lower_name##_init_once(void)		\
+{							\
+	struct fs *fs = &fs__##lower_name;		\
+							\
+	fs__init_once(fs);				\
+}							\
+							\
+const char *lower_name##__mountpoint(void)		\
+{							\
+	static pthread_once_t init_once = PTHREAD_ONCE_INIT;	\
+	struct fs *fs = &fs__##lower_name;		\
+							\
+	pthread_once(&init_once, lower_name##_init_once);	\
+	return fs__mountpoint(fs);			\
+}							\
+							\
+const char *lower_name##__mount(void)			\
+{							\
+	const char *mountpoint = lower_name##__mountpoint();	\
+	struct fs *fs = &fs__##lower_name;		\
+							\
+	if (mountpoint)					\
+		return mountpoint;			\
+							\
+	return fs__mount(fs);				\
+}							\
+							\
+bool lower_name##__configured(void)			\
+{							\
+	return lower_name##__mountpoint() != NULL;	\
+}
+
+FS(sysfs, sysfs, SYSFS);
+FS(procfs, procfs, PROC_SUPER);
+FS(debugfs, debugfs, DEBUGFS);
+FS(tracefs, tracefs, TRACEFS);
+FS(hugetlbfs, hugetlbfs, HUGETLBFS);
+FS(bpf_fs, bpf, BPF_FS);
+
+static bool fs__read_mounts(struct fs *fs)
+{
+	char type[100];
+	FILE *fp;
+	char path[PATH_MAX + 1];
+
+	fp = fopen("/proc/mounts", "r");
+	if (fp == NULL)
+		return false;
+
+	while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
+		      path, type) == 2) {
+
+		if (strcmp(type, fs->name) == 0) {
+			fs->path = strdup(path);
+			fclose(fp);
+			return fs->path != NULL;
+		}
+	}
+	fclose(fp);
+	return false;
+}
+
+static int fs__valid_mount(const char *fs, long magic)
+{
+	struct statfs st_fs;
+
+	if (statfs(fs, &st_fs) < 0)
+		return -ENOENT;
+	else if ((long)st_fs.f_type != magic)
+		return -ENOENT;
+
+	return 0;
+}
+
+static bool fs__check_mounts(struct fs *fs)
+{
+	const char * const *ptr;
+
+	ptr = fs->mounts;
+	while (*ptr) {
+		if (fs__valid_mount(*ptr, fs->magic) == 0) {
+			fs->path = strdup(*ptr);
+			if (!fs->path)
+				return false;
+			return true;
+		}
+		ptr++;
+	}
+
+	return false;
+}
+
+static void mem_toupper(char *f, size_t len)
+{
+	while (len) {
+		*f = toupper(*f);
+		f++;
+		len--;
+	}
+}
+
+/*
+ * Check for "NAME_PATH" environment variable to override fs location (for
+ * testing). This matches the recommendation in Documentation/admin-guide/sysfs-rules.rst
+ * for SYSFS_PATH.
+ */
+static bool fs__env_override(struct fs *fs)
+{
+	char *override_path;
+	size_t name_len = strlen(fs->name);
+	/* name + "_PATH" + '\0' */
+	char upper_name[name_len + 5 + 1];
+
+	memcpy(upper_name, fs->name, name_len);
+	mem_toupper(upper_name, name_len);
+	strcpy(&upper_name[name_len], "_PATH");
+
+	override_path = getenv(upper_name);
+	if (!override_path)
+		return false;
+
+	fs->path = strdup(override_path);
+	if (!fs->path)
+		return false;
+	return true;
+}
+
+static void fs__init_once(struct fs *fs)
+{
+	if (!fs__env_override(fs) &&
+	    !fs__check_mounts(fs) &&
+	    !fs__read_mounts(fs)) {
+		assert(!fs->path);
+	} else {
+		assert(fs->path);
+	}
+}
+
+static const char *fs__mountpoint(const struct fs *fs)
+{
+	return fs->path;
+}
+
+static const char *mount_overload(struct fs *fs)
+{
+	size_t name_len = strlen(fs->name);
+	/* "PERF_" + name + "_ENVIRONMENT" + '\0' */
+	char upper_name[5 + name_len + 12 + 1];
+
+	snprintf(upper_name, sizeof(upper_name), "PERF_%s_ENVIRONMENT", fs->name);
+	mem_toupper(upper_name, strlen(upper_name));
+
+	return getenv(upper_name) ?: *fs->mounts;
+}
+
+static const char *fs__mount(struct fs *fs)
+{
+	const char *mountpoint;
+
+	pthread_mutex_lock(&fs->mount_mutex);
+
+	/* Check if path found inside the mutex to avoid races with other callers of mount. */
+	mountpoint = fs__mountpoint(fs);
+	if (mountpoint)
+		goto out;
+
+	mountpoint = mount_overload(fs);
+
+	if (mount(NULL, mountpoint, fs->name, 0, NULL) == 0 &&
+	    fs__valid_mount(mountpoint, fs->magic) == 0) {
+		fs->path = strdup(mountpoint);
+		mountpoint = fs->path;
+	}
+out:
+	pthread_mutex_unlock(&fs->mount_mutex);
+	return mountpoint;
+}
+
+int filename__read_int(const char *filename, int *value)
+{
+	char line[64];
+	int fd = open(filename, O_RDONLY), err = -1;
+	ssize_t n;
+
+	if (fd < 0)
+		return -errno;
+
+	n = read(fd, line, sizeof(line) - 1);
+	if (n > 0) {
+		line[n] = '\0';
+		*value = atoi(line);
+		err = 0;
+	}
+
+	close(fd);
+	return err;
+}
+
+static int filename__read_ull_base(const char *filename,
+				   unsigned long long *value, int base)
+{
+	char line[64];
+	int fd = open(filename, O_RDONLY), err = -1;
+	ssize_t n;
+
+	if (fd < 0)
+		return -errno;
+
+	n = read(fd, line, sizeof(line) - 1);
+	if (n > 0) {
+		line[n] = '\0';
+		*value = strtoull(line, NULL, base);
+		if (*value != ULLONG_MAX)
+			err = 0;
+	}
+
+	close(fd);
+	return err;
+}
+
+/*
+ * Parses @value out of @filename with strtoull.
+ * By using 16 for base to treat the number as hex.
+ */
+int filename__read_xll(const char *filename, unsigned long long *value)
+{
+	return filename__read_ull_base(filename, value, 16);
+}
+
+/*
+ * Parses @value out of @filename with strtoull.
+ * By using 0 for base, the strtoull detects the
+ * base automatically (see man strtoull).
+ */
+int filename__read_ull(const char *filename, unsigned long long *value)
+{
+	return filename__read_ull_base(filename, value, 0);
+}
+
+int filename__read_str(const char *filename, char **buf, size_t *sizep)
+{
+	struct io io;
+	char bf[128];
+	int err;
+
+	io.fd = open(filename, O_RDONLY);
+	if (io.fd < 0)
+		return -errno;
+	io__init(&io, io.fd, bf, sizeof(bf));
+	*buf = NULL;
+	err = io__getdelim(&io, buf, sizep, /*delim=*/-1);
+	if (err < 0) {
+		free(*buf);
+		*buf = NULL;
+	} else
+		err = 0;
+	close(io.fd);
+	return err;
+}
+
+int filename__write_int(const char *filename, int value)
+{
+	int fd = open(filename, O_WRONLY), err = -1;
+	char buf[64];
+	int len;
+
+	if (fd < 0)
+		return -errno;
+
+	len = sprintf(buf, "%d", value);
+	if (write(fd, buf, len) == len)
+		err = 0;
+
+	close(fd);
+	return err;
+}
+
+int procfs__read_str(const char *entry, char **buf, size_t *sizep)
+{
+	char path[PATH_MAX];
+	const char *procfs = procfs__mountpoint();
+
+	if (!procfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", procfs, entry);
+
+	return filename__read_str(path, buf, sizep);
+}
+
+static int sysfs__read_ull_base(const char *entry,
+				unsigned long long *value, int base)
+{
+	char path[PATH_MAX];
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
+
+	return filename__read_ull_base(path, value, base);
+}
+
+int sysfs__read_xll(const char *entry, unsigned long long *value)
+{
+	return sysfs__read_ull_base(entry, value, 16);
+}
+
+int sysfs__read_ull(const char *entry, unsigned long long *value)
+{
+	return sysfs__read_ull_base(entry, value, 0);
+}
+
+int sysfs__read_int(const char *entry, int *value)
+{
+	char path[PATH_MAX];
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
+
+	return filename__read_int(path, value);
+}
+
+int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
+{
+	char path[PATH_MAX];
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
+
+	return filename__read_str(path, buf, sizep);
+}
+
+int sysfs__read_bool(const char *entry, bool *value)
+{
+	struct io io;
+	char bf[16];
+	int ret = 0;
+	char path[PATH_MAX];
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
+	io.fd = open(path, O_RDONLY);
+	if (io.fd < 0)
+		return -errno;
+
+	io__init(&io, io.fd, bf, sizeof(bf));
+	switch (io__get_char(&io)) {
+	case '1':
+	case 'y':
+	case 'Y':
+		*value = true;
+		break;
+	case '0':
+	case 'n':
+	case 'N':
+		*value = false;
+		break;
+	default:
+		ret = -1;
+	}
+	close(io.fd);
+
+	return ret;
+}
+int sysctl__read_int(const char *sysctl, int *value)
+{
+	char path[PATH_MAX];
+	const char *procfs = procfs__mountpoint();
+
+	if (!procfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
+
+	return filename__read_int(path, value);
+}
+
+int sysfs__write_int(const char *entry, int value)
+{
+	char path[PATH_MAX];
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return -1;
+
+	if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX)
+		return -1;
+
+	return filename__write_int(path, value);
+}
diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h
new file mode 100644
index 000000000..aa222ca30
--- /dev/null
+++ b/tools/lib/api/fs/fs.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_FS__
+#define __API_FS__
+
+#include <stdbool.h>
+#include <unistd.h>
+
+/*
+ * On most systems <limits.h> would have given us this, but  not on some systems
+ * (e.g. GNU/Hurd).
+ */
+#ifndef PATH_MAX
+#define PATH_MAX 4096
+#endif
+
+#define FS(name)				\
+	const char *name##__mountpoint(void);	\
+	const char *name##__mount(void);	\
+	bool name##__configured(void);		\
+
+/*
+ * The xxxx__mountpoint() entry points find the first match mount point for each
+ * filesystems listed below, where xxxx is the filesystem type.
+ *
+ * The interface is as follows:
+ *
+ * - If a mount point is found on first call, it is cached and used for all
+ *   subsequent calls.
+ *
+ * - If a mount point is not found, NULL is returned on first call and all
+ *   subsequent calls.
+ */
+FS(sysfs)
+FS(procfs)
+FS(debugfs)
+FS(tracefs)
+FS(hugetlbfs)
+FS(bpf_fs)
+
+#undef FS
+
+
+int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys);
+
+int filename__read_int(const char *filename, int *value);
+int filename__read_ull(const char *filename, unsigned long long *value);
+int filename__read_xll(const char *filename, unsigned long long *value);
+int filename__read_str(const char *filename, char **buf, size_t *sizep);
+
+int filename__write_int(const char *filename, int value);
+
+int procfs__read_str(const char *entry, char **buf, size_t *sizep);
+
+int sysctl__read_int(const char *sysctl, int *value);
+int sysfs__read_int(const char *entry, int *value);
+int sysfs__read_ull(const char *entry, unsigned long long *value);
+int sysfs__read_xll(const char *entry, unsigned long long *value);
+int sysfs__read_str(const char *entry, char **buf, size_t *sizep);
+int sysfs__read_bool(const char *entry, bool *value);
+
+int sysfs__write_int(const char *entry, int value);
+#endif /* __API_FS__ */
diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c
new file mode 100644
index 000000000..834fd64c7
--- /dev/null
+++ b/tools/lib/api/fs/tracing_path.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <linux/string.h>
+#include <errno.h>
+#include <unistd.h>
+#include "fs.h"
+
+#include "tracing_path.h"
+
+static char tracing_path[PATH_MAX]        = "/sys/kernel/tracing";
+
+static void __tracing_path_set(const char *tracing, const char *mountpoint)
+{
+	snprintf(tracing_path, sizeof(tracing_path), "%s/%s",
+		 mountpoint, tracing);
+}
+
+static const char *tracing_path_tracefs_mount(void)
+{
+	const char *mnt;
+
+	mnt = tracefs__mount();
+	if (!mnt)
+		return NULL;
+
+	__tracing_path_set("", mnt);
+
+	return tracing_path;
+}
+
+static const char *tracing_path_debugfs_mount(void)
+{
+	const char *mnt;
+
+	mnt = debugfs__mount();
+	if (!mnt)
+		return NULL;
+
+	__tracing_path_set("tracing/", mnt);
+
+	return tracing_path;
+}
+
+const char *tracing_path_mount(void)
+{
+	const char *mnt;
+
+	mnt = tracing_path_tracefs_mount();
+	if (mnt)
+		return mnt;
+
+	mnt = tracing_path_debugfs_mount();
+
+	return mnt;
+}
+
+void tracing_path_set(const char *mntpt)
+{
+	__tracing_path_set("tracing/", mntpt);
+}
+
+char *get_tracing_file(const char *name)
+{
+	char *file;
+
+	if (asprintf(&file, "%s%s", tracing_path_mount(), name) < 0)
+		return NULL;
+
+	return file;
+}
+
+void put_tracing_file(char *file)
+{
+	free(file);
+}
+
+char *get_events_file(const char *name)
+{
+	char *file;
+
+	if (asprintf(&file, "%s/events/%s", tracing_path_mount(), name) < 0)
+		return NULL;
+
+	return file;
+}
+
+void put_events_file(char *file)
+{
+	free(file);
+}
+
+DIR *tracing_events__opendir(void)
+{
+	DIR *dir = NULL;
+	char *path = get_tracing_file("events");
+
+	if (path) {
+		dir = opendir(path);
+		put_events_file(path);
+	}
+
+	return dir;
+}
+
+int tracing_events__scandir_alphasort(struct dirent ***namelist)
+{
+	char *path = get_tracing_file("events");
+	int ret;
+
+	if (!path) {
+		*namelist = NULL;
+		return 0;
+	}
+
+	ret = scandir(path, namelist, NULL, alphasort);
+	put_events_file(path);
+
+	return ret;
+}
+
+int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
+				   const char *sys, const char *name)
+{
+	char sbuf[128];
+	char filename[PATH_MAX];
+
+	snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*");
+
+	switch (err) {
+	case ENOENT:
+		/*
+		 * We will get here if we can't find the tracepoint, but one of
+		 * debugfs or tracefs is configured, which means you probably
+		 * want some tracepoint which wasn't compiled in your kernel.
+		 * - jirka
+		 */
+		if (debugfs__configured() || tracefs__configured()) {
+			/* sdt markers */
+			if (!strncmp(filename, "sdt_", 4)) {
+				snprintf(buf, size,
+					"Error:\tFile %s/events/%s not found.\n"
+					"Hint:\tSDT event cannot be directly recorded on.\n"
+					"\tPlease first use 'perf probe %s:%s' before recording it.\n",
+					tracing_path, filename, sys, name);
+			} else {
+				snprintf(buf, size,
+					 "Error:\tFile %s/events/%s not found.\n"
+					 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
+					 tracing_path, filename);
+			}
+			break;
+		}
+		snprintf(buf, size, "%s",
+			 "Error:\tUnable to find debugfs/tracefs\n"
+			 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n"
+			 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n"
+			 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
+		break;
+	case EACCES: {
+		snprintf(buf, size,
+			 "Error:\tNo permissions to read %s/events/%s\n"
+			 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
+			 tracing_path, filename, tracing_path_mount());
+	}
+		break;
+	default:
+		snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
+		break;
+	}
+
+	return 0;
+}
diff --git a/tools/lib/api/fs/tracing_path.h b/tools/lib/api/fs/tracing_path.h
new file mode 100644
index 000000000..fc6347c11
--- /dev/null
+++ b/tools/lib/api/fs/tracing_path.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_FS_TRACING_PATH_H
+#define __API_FS_TRACING_PATH_H
+
+#include <linux/types.h>
+#include <dirent.h>
+
+DIR *tracing_events__opendir(void);
+int tracing_events__scandir_alphasort(struct dirent ***namelist);
+
+void tracing_path_set(const char *mountpoint);
+const char *tracing_path_mount(void);
+
+char *get_tracing_file(const char *name);
+void put_tracing_file(char *file);
+
+char *get_events_file(const char *name);
+void put_events_file(char *file);
+
+#define zput_events_file(ptr) ({ free(*ptr); *ptr = NULL; })
+
+int tracing_path__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name);
+#endif /* __API_FS_TRACING_PATH_H */
diff --git a/tools/lib/api/io.h b/tools/lib/api/io.h
new file mode 100644
index 000000000..1731996b2
--- /dev/null
+++ b/tools/lib/api/io.h
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Lightweight buffered reading library.
+ *
+ * Copyright 2019 Google LLC.
+ */
+#ifndef __API_IO__
+#define __API_IO__
+
+#include <errno.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/types.h>
+
+struct io {
+	/* File descriptor being read/ */
+	int fd;
+	/* Size of the read buffer. */
+	unsigned int buf_len;
+	/* Pointer to storage for buffering read. */
+	char *buf;
+	/* End of the storage. */
+	char *end;
+	/* Currently accessed data pointer. */
+	char *data;
+	/* Read timeout, 0 implies no timeout. */
+	int timeout_ms;
+	/* Set true on when the end of file on read error. */
+	bool eof;
+};
+
+static inline void io__init(struct io *io, int fd,
+			    char *buf, unsigned int buf_len)
+{
+	io->fd = fd;
+	io->buf_len = buf_len;
+	io->buf = buf;
+	io->end = buf;
+	io->data = buf;
+	io->timeout_ms = 0;
+	io->eof = false;
+}
+
+/* Read from fd filling the buffer. Called when io->data == io->end. */
+static inline int io__fill_buffer(struct io *io)
+{
+	ssize_t n;
+
+	if (io->eof)
+		return -1;
+
+	if (io->timeout_ms != 0) {
+		struct pollfd pfds[] = {
+			{
+				.fd = io->fd,
+				.events = POLLIN,
+			},
+		};
+
+		n = poll(pfds, 1, io->timeout_ms);
+		if (n == 0)
+			errno = ETIMEDOUT;
+		if (n > 0 && !(pfds[0].revents & POLLIN)) {
+			errno = EIO;
+			n = -1;
+		}
+		if (n <= 0) {
+			io->eof = true;
+			return -1;
+		}
+	}
+	n = read(io->fd, io->buf, io->buf_len);
+
+	if (n <= 0) {
+		io->eof = true;
+		return -1;
+	}
+	io->data = &io->buf[0];
+	io->end = &io->buf[n];
+	return 0;
+}
+
+/* Reads one character from the "io" file with similar semantics to fgetc. */
+static inline int io__get_char(struct io *io)
+{
+	if (io->data == io->end) {
+		int ret = io__fill_buffer(io);
+
+		if (ret)
+			return ret;
+	}
+	return *io->data++;
+}
+
+/* Read a hexadecimal value with no 0x prefix into the out argument hex. If the
+ * first character isn't hexadecimal returns -2, io->eof returns -1, otherwise
+ * returns the character after the hexadecimal value which may be -1 for eof.
+ * If the read value is larger than a u64 the high-order bits will be dropped.
+ */
+static inline int io__get_hex(struct io *io, __u64 *hex)
+{
+	bool first_read = true;
+
+	*hex = 0;
+	while (true) {
+		int ch = io__get_char(io);
+
+		if (ch < 0)
+			return ch;
+		if (ch >= '0' && ch <= '9')
+			*hex = (*hex << 4) | (ch - '0');
+		else if (ch >= 'a' && ch <= 'f')
+			*hex = (*hex << 4) | (ch - 'a' + 10);
+		else if (ch >= 'A' && ch <= 'F')
+			*hex = (*hex << 4) | (ch - 'A' + 10);
+		else if (first_read)
+			return -2;
+		else
+			return ch;
+		first_read = false;
+	}
+}
+
+/* Read a positive decimal value with out argument dec. If the first character
+ * isn't a decimal returns -2, io->eof returns -1, otherwise returns the
+ * character after the decimal value which may be -1 for eof. If the read value
+ * is larger than a u64 the high-order bits will be dropped.
+ */
+static inline int io__get_dec(struct io *io, __u64 *dec)
+{
+	bool first_read = true;
+
+	*dec = 0;
+	while (true) {
+		int ch = io__get_char(io);
+
+		if (ch < 0)
+			return ch;
+		if (ch >= '0' && ch <= '9')
+			*dec = (*dec * 10) + ch - '0';
+		else if (first_read)
+			return -2;
+		else
+			return ch;
+		first_read = false;
+	}
+}
+
+/* Read up to and including the first delim. */
+static inline ssize_t io__getdelim(struct io *io, char **line_out, size_t *line_len_out, int delim)
+{
+	char buf[128];
+	int buf_pos = 0;
+	char *line = NULL, *temp;
+	size_t line_len = 0;
+	int ch = 0;
+
+	/* TODO: reuse previously allocated memory. */
+	free(*line_out);
+	while (ch != delim) {
+		ch = io__get_char(io);
+
+		if (ch < 0)
+			break;
+
+		if (buf_pos == sizeof(buf)) {
+			temp = realloc(line, line_len + sizeof(buf));
+			if (!temp)
+				goto err_out;
+			line = temp;
+			memcpy(&line[line_len], buf, sizeof(buf));
+			line_len += sizeof(buf);
+			buf_pos = 0;
+		}
+		buf[buf_pos++] = (char)ch;
+	}
+	temp = realloc(line, line_len + buf_pos + 1);
+	if (!temp)
+		goto err_out;
+	line = temp;
+	memcpy(&line[line_len], buf, buf_pos);
+	line[line_len + buf_pos] = '\0';
+	line_len += buf_pos;
+	*line_out = line;
+	*line_len_out = line_len;
+	return line_len;
+err_out:
+	free(line);
+	*line_out = NULL;
+	*line_len_out = 0;
+	return -ENOMEM;
+}
+
+static inline ssize_t io__getline(struct io *io, char **line_out, size_t *line_len_out)
+{
+	return io__getdelim(io, line_out, line_len_out, /*delim=*/'\n');
+}
+
+#endif /* __API_IO__ */
diff --git a/tools/lib/api/io_dir.h b/tools/lib/api/io_dir.h
new file mode 100644
index 000000000..ef83e967e
--- /dev/null
+++ b/tools/lib/api/io_dir.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/*
+ * Lightweight directory reading library.
+ */
+#ifndef __API_IO_DIR__
+#define __API_IO_DIR__
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <linux/limits.h>
+
+#if !defined(SYS_getdents64)
+#if defined(__x86_64__) || defined(__arm__)
+  #define SYS_getdents64 217
+#elif defined(__i386__) || defined(__s390x__) || defined(__sh__)
+  #define SYS_getdents64 220
+#elif defined(__alpha__)
+  #define SYS_getdents64 377
+#elif defined(__mips__)
+  #define SYS_getdents64 308
+#elif defined(__powerpc64__) || defined(__powerpc__)
+  #define SYS_getdents64 202
+#elif defined(__sparc64__) || defined(__sparc__)
+  #define SYS_getdents64 154
+#elif defined(__xtensa__)
+  #define SYS_getdents64 60
+#else
+  #define SYS_getdents64 61
+#endif
+#endif /* !defined(SYS_getdents64) */
+
+static inline ssize_t perf_getdents64(int fd, void *dirp, size_t count)
+{
+#ifdef MEMORY_SANITIZER
+	memset(dirp, 0, count);
+#endif
+	return syscall(SYS_getdents64, fd, dirp, count);
+}
+
+struct io_dirent64 {
+	ino64_t        d_ino;    /* 64-bit inode number */
+	off64_t        d_off;    /* 64-bit offset to next structure */
+	unsigned short d_reclen; /* Size of this dirent */
+	unsigned char  d_type;   /* File type */
+	char           d_name[NAME_MAX + 1]; /* Filename (null-terminated) */
+};
+
+struct io_dir {
+	int dirfd;
+	ssize_t available_bytes;
+	struct io_dirent64 *next;
+	struct io_dirent64 buff[4];
+};
+
+static inline void io_dir__init(struct io_dir *iod, int dirfd)
+{
+	iod->dirfd = dirfd;
+	iod->available_bytes = 0;
+}
+
+static inline void io_dir__rewinddir(struct io_dir *iod)
+{
+	lseek(iod->dirfd, 0, SEEK_SET);
+	iod->available_bytes = 0;
+}
+
+static inline struct io_dirent64 *io_dir__readdir(struct io_dir *iod)
+{
+	struct io_dirent64 *entry;
+
+	if (iod->available_bytes <= 0) {
+		ssize_t rc = perf_getdents64(iod->dirfd, iod->buff, sizeof(iod->buff));
+
+		if (rc <= 0)
+			return NULL;
+		iod->available_bytes = rc;
+		iod->next = iod->buff;
+	}
+	entry = iod->next;
+	iod->next = (struct io_dirent64 *)((char *)entry + entry->d_reclen);
+	iod->available_bytes -= entry->d_reclen;
+	return entry;
+}
+
+static inline bool io_dir__is_dir(const struct io_dir *iod, struct io_dirent64 *dent)
+{
+	if (dent->d_type == DT_UNKNOWN) {
+		struct stat st;
+
+		if (fstatat(iod->dirfd, dent->d_name, &st, /*flags=*/0))
+			return false;
+
+		if (S_ISDIR(st.st_mode)) {
+			dent->d_type = DT_DIR;
+			return true;
+		}
+	}
+	return dent->d_type == DT_DIR;
+}
+
+#endif  /* __API_IO_DIR__ */
diff --git a/tools/lib/argv_split.c b/tools/lib/argv_split.c
new file mode 100644
index 000000000..0a58ccf3f
--- /dev/null
+++ b/tools/lib/argv_split.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helper function for splitting a string into an argv-like array.
+ */
+
+#include <stdlib.h>
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+
+static const char *skip_arg(const char *cp)
+{
+	while (*cp && !isspace(*cp))
+		cp++;
+
+	return cp;
+}
+
+static int count_argc(const char *str)
+{
+	int count = 0;
+
+	while (*str) {
+		str = skip_spaces(str);
+		if (*str) {
+			count++;
+			str = skip_arg(str);
+		}
+	}
+
+	return count;
+}
+
+/**
+ * argv_free - free an argv
+ * @argv - the argument vector to be freed
+ *
+ * Frees an argv and the strings it points to.
+ */
+void argv_free(char **argv)
+{
+	char **p;
+	for (p = argv; *p; p++) {
+		free(*p);
+		*p = NULL;
+	}
+
+	free(argv);
+}
+
+/**
+ * argv_split - split a string at whitespace, returning an argv
+ * @str: the string to be split
+ * @argcp: returned argument count
+ *
+ * Returns an array of pointers to strings which are split out from
+ * @str.  This is performed by strictly splitting on white-space; no
+ * quote processing is performed.  Multiple whitespace characters are
+ * considered to be a single argument separator.  The returned array
+ * is always NULL-terminated.  Returns NULL on memory allocation
+ * failure.
+ */
+char **argv_split(const char *str, int *argcp)
+{
+	int argc = count_argc(str);
+	char **argv = calloc(argc + 1, sizeof(*argv));
+	char **argvp;
+
+	if (argv == NULL)
+		goto out;
+
+	if (argcp)
+		*argcp = argc;
+
+	argvp = argv;
+
+	while (*str) {
+		str = skip_spaces(str);
+
+		if (*str) {
+			const char *p = str;
+			char *t;
+
+			str = skip_arg(str);
+
+			t = strndup(p, str-p);
+			if (t == NULL)
+				goto fail;
+			*argvp++ = t;
+		}
+	}
+	*argvp = NULL;
+
+out:
+	return argv;
+
+fail:
+	argv_free(argv);
+	return NULL;
+}
diff --git a/tools/lib/bitmap.c b/tools/lib/bitmap.c
new file mode 100644
index 000000000..fedc9070f
--- /dev/null
+++ b/tools/lib/bitmap.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * From lib/bitmap.c
+ * Helper functions for bitmap.h.
+ */
+#include <linux/bitmap.h>
+
+unsigned int __bitmap_weight(const unsigned long *bitmap, int bits)
+{
+	unsigned int k, w = 0, lim = bits/BITS_PER_LONG;
+
+	for (k = 0; k < lim; k++)
+		w += hweight_long(bitmap[k]);
+
+	if (bits % BITS_PER_LONG)
+		w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
+
+	return w;
+}
+
+void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+		 const unsigned long *bitmap2, int bits)
+{
+	int k;
+	int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] | bitmap2[k];
+}
+
+size_t bitmap_scnprintf(unsigned long *bitmap, unsigned int nbits,
+			char *buf, size_t size)
+{
+	/* current bit is 'cur', most recently seen range is [rbot, rtop] */
+	unsigned int cur, rbot, rtop;
+	bool first = true;
+	size_t ret = 0;
+
+	rbot = cur = find_first_bit(bitmap, nbits);
+	while (cur < nbits) {
+		rtop = cur;
+		cur = find_next_bit(bitmap, nbits, cur + 1);
+		if (cur < nbits && cur <= rtop + 1)
+			continue;
+
+		if (!first)
+			ret += scnprintf(buf + ret, size - ret, ",");
+
+		first = false;
+
+		ret += scnprintf(buf + ret, size - ret, "%d", rbot);
+		if (rbot < rtop)
+			ret += scnprintf(buf + ret, size - ret, "-%d", rtop);
+
+		rbot = cur;
+	}
+	return ret;
+}
+
+bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+		 const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int lim = bits/BITS_PER_LONG;
+	unsigned long result = 0;
+
+	for (k = 0; k < lim; k++)
+		result |= (dst[k] = bitmap1[k] & bitmap2[k]);
+	if (bits % BITS_PER_LONG)
+		result |= (dst[k] = bitmap1[k] & bitmap2[k] &
+			   BITMAP_LAST_WORD_MASK(bits));
+	return result != 0;
+}
+
+bool __bitmap_equal(const unsigned long *bitmap1,
+		    const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] != bitmap2[k])
+			return false;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return false;
+
+	return true;
+}
+
+bool __bitmap_intersects(const unsigned long *bitmap1,
+			 const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] & bitmap2[k])
+			return true;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return true;
+	return false;
+}
+
+void __bitmap_set(unsigned long *map, unsigned int start, int len)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const unsigned int size = start + len;
+	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+	while (len - bits_to_set >= 0) {
+		*p |= mask_to_set;
+		len -= bits_to_set;
+		bits_to_set = BITS_PER_LONG;
+		mask_to_set = ~0UL;
+		p++;
+	}
+	if (len) {
+		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+		*p |= mask_to_set;
+	}
+}
+
+void __bitmap_clear(unsigned long *map, unsigned int start, int len)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const unsigned int size = start + len;
+	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+	while (len - bits_to_clear >= 0) {
+		*p &= ~mask_to_clear;
+		len -= bits_to_clear;
+		bits_to_clear = BITS_PER_LONG;
+		mask_to_clear = ~0UL;
+		p++;
+	}
+	if (len) {
+		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+		*p &= ~mask_to_clear;
+	}
+}
+
+bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int lim = bits/BITS_PER_LONG;
+	unsigned long result = 0;
+
+	for (k = 0; k < lim; k++)
+		result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
+	if (bits % BITS_PER_LONG)
+		result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
+			   BITMAP_LAST_WORD_MASK(bits));
+	return result != 0;
+}
+
+bool __bitmap_subset(const unsigned long *bitmap1,
+		     const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] & ~bitmap2[k])
+			return false;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return false;
+	return true;
+}
+
+void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] ^ bitmap2[k];
+}
diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore
new file mode 100644
index 000000000..f02725b12
--- /dev/null
+++ b/tools/lib/bpf/.gitignore
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+libbpf.pc
+libbpf.so.*
+TAGS
+tags
+cscope.*
+/bpf_helper_defs.h
+fixdep
diff --git a/tools/lib/bpf/Build b/tools/lib/bpf/Build
new file mode 100644
index 000000000..c80204bb7
--- /dev/null
+++ b/tools/lib/bpf/Build
@@ -0,0 +1,4 @@
+libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_utils.o \
+	    netlink.o bpf_prog_linfo.o libbpf_probes.o hashmap.o \
+	    btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o \
+	    usdt.o zip.o elf.o features.o btf_iter.o btf_relocate.o
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
new file mode 100644
index 000000000..269fe21fc
--- /dev/null
+++ b/tools/lib/bpf/Makefile
@@ -0,0 +1,302 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+# Most of this file is copied from tools/lib/traceevent/Makefile
+
+RM ?= rm
+srctree := $(realpath $(srctree))
+
+VERSION_SCRIPT := libbpf.map
+LIBBPF_VERSION := $(shell \
+	grep -oE '^LIBBPF_([0-9.]+)' $(VERSION_SCRIPT) | \
+	sort -rV | head -n1 | cut -d'_' -f2)
+LIBBPF_MAJOR_VERSION := $(word 1,$(subst ., ,$(LIBBPF_VERSION)))
+LIBBPF_MINOR_VERSION := $(word 2,$(subst ., ,$(LIBBPF_VERSION)))
+
+MAKEFLAGS += --no-print-directory
+
+# This will work when bpf is built in tools env. where srctree
+# isn't set and when invoked from selftests build, where srctree
+# is a ".". building_out_of_srctree is undefined for in srctree
+# builds
+ifndef building_out_of_srctree
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+INSTALL = install
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+include $(srctree)/tools/scripts/Makefile.arch
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?= /usr/local
+libdir = $(prefix)/$(libdir_relative)
+man_dir = $(prefix)/share/man
+man_dir_SQ = '$(subst ','\'',$(man_dir))'
+
+export man_dir man_dir_SQ INSTALL
+export DESTDIR DESTDIR_SQ
+
+# Defer assigning EXTRA_CFLAGS to CFLAGS until after including
+# tools/scripts/Makefile.include, as it may add flags to EXTRA_CFLAGS.
+ifdef EXTRA_CFLAGS
+  CFLAGS :=
+else
+  CFLAGS := -g -O2
+endif
+
+include $(srctree)/tools/scripts/Makefile.include
+
+# copy a bit from Linux kbuild
+
+INCLUDES = -I$(or $(OUTPUT),.) \
+	   -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi \
+	   -I$(srctree)/tools/arch/$(SRCARCH)/include
+
+export prefix libdir src obj
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
+
+OBJ		= $@
+N		=
+
+LIB_TARGET	= libbpf.a libbpf.so.$(LIBBPF_VERSION)
+LIB_FILE	= libbpf.a libbpf.so*
+PC_FILE		= libbpf.pc
+
+# Append required CFLAGS
+override CFLAGS += -std=gnu89
+override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum
+override CFLAGS += -Werror -Wall
+override CFLAGS += $(INCLUDES)
+override CFLAGS += -fvisibility=hidden
+override CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
+override CFLAGS += $(EXTRA_CFLAGS)
+
+# flags specific for shared library
+SHLIB_FLAGS := -DSHARED -fPIC
+
+# Disable command line variables (CFLAGS) override from top
+# level Makefile (perf), otherwise build Makefile will get
+# the same command line setup.
+MAKEOVERRIDES=
+
+all:
+
+OUTPUT ?= ./
+OUTPUT := $(abspath $(OUTPUT))/
+export srctree OUTPUT CC LD CFLAGS V
+include $(srctree)/tools/build/Makefile.include
+
+SHARED_OBJDIR	:= $(OUTPUT)sharedobjs/
+STATIC_OBJDIR	:= $(OUTPUT)staticobjs/
+BPF_IN_SHARED	:= $(SHARED_OBJDIR)libbpf-in.o
+BPF_IN_STATIC	:= $(STATIC_OBJDIR)libbpf-in.o
+BPF_HELPER_DEFS	:= $(OUTPUT)bpf_helper_defs.h
+BPF_GENERATED	:= $(BPF_HELPER_DEFS)
+
+LIB_TARGET	:= $(addprefix $(OUTPUT),$(LIB_TARGET))
+LIB_FILE	:= $(addprefix $(OUTPUT),$(LIB_FILE))
+PC_FILE		:= $(addprefix $(OUTPUT),$(PC_FILE))
+
+TAGS_PROG := $(if $(shell which etags 2>/dev/null),etags,ctags)
+
+GLOBAL_SYM_COUNT = $(shell $(HOSTREADELF) -s --wide $(BPF_IN_SHARED) | \
+			   cut -d "@" -f1 | sed 's/_v[0-9]_[0-9]_[0-9].*//' | \
+			   sed 's/\[.*\]//' | \
+			   awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \
+			   sort -u | wc -l)
+VERSIONED_SYM_COUNT = $(shell $(HOSTREADELF) --dyn-syms --wide $(OUTPUT)libbpf.so | \
+			      sed 's/\[.*\]//' | \
+			      awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \
+			      grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l)
+
+CMD_TARGETS = $(LIB_TARGET) $(PC_FILE)
+
+all: fixdep
+	$(Q)$(MAKE) all_cmd
+
+all_cmd: $(CMD_TARGETS) check
+
+$(SHARED_OBJDIR) $(STATIC_OBJDIR):
+	$(Q)mkdir -p $@
+
+$(BPF_IN_SHARED): force $(BPF_GENERATED) | $(SHARED_OBJDIR)
+	@(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
+	(diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \
+	echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true
+	@(test -f ../../include/uapi/linux/bpf_common.h -a -f ../../../include/uapi/linux/bpf_common.h && ( \
+	(diff -B ../../include/uapi/linux/bpf_common.h ../../../include/uapi/linux/bpf_common.h >/dev/null) || \
+	echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf_common.h' differs from latest version at 'include/uapi/linux/bpf_common.h'" >&2 )) || true
+	@(test -f ../../include/uapi/linux/if_xdp.h -a -f ../../../include/uapi/linux/if_xdp.h && ( \
+	(diff -B ../../include/uapi/linux/if_xdp.h ../../../include/uapi/linux/if_xdp.h >/dev/null) || \
+	echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true
+	$(SILENT_MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= OUTPUT=$(SHARED_OBJDIR) $(SHARED_OBJDIR)fixdep
+	$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)"
+
+$(BPF_IN_STATIC): force $(BPF_GENERATED) | $(STATIC_OBJDIR)
+	$(SILENT_MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= OUTPUT=$(STATIC_OBJDIR) $(STATIC_OBJDIR)fixdep
+	$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR)
+
+$(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h
+	$(QUIET_GEN)$(srctree)/scripts/bpf_doc.py --header \
+		--file $(srctree)/tools/include/uapi/linux/bpf.h > $(BPF_HELPER_DEFS)
+
+$(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
+
+$(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED) $(VERSION_SCRIPT)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) \
+		--shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
+		-Wl,--version-script=$(VERSION_SCRIPT) $< -lelf -lz -o $@
+	@ln -sf $(@F) $(OUTPUT)libbpf.so
+	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
+
+$(OUTPUT)libbpf.a: $(BPF_IN_STATIC)
+	$(QUIET_LINK)$(RM) -f $@; $(AR) rcs $@ $^
+
+$(OUTPUT)libbpf.pc:
+	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
+		-e "s|@LIBDIR@|$(libdir_SQ)|" \
+		-e "s|@VERSION@|$(LIBBPF_VERSION)|" \
+		< libbpf.pc.template > $@
+
+check: check_abi check_version
+
+check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT)
+	@if [ "$(GLOBAL_SYM_COUNT)" != "$(VERSIONED_SYM_COUNT)" ]; then	 \
+		echo "Warning: Num of global symbols in $(BPF_IN_SHARED)"	 \
+		     "($(GLOBAL_SYM_COUNT)) does NOT match with num of"	 \
+		     "versioned symbols in $^ ($(VERSIONED_SYM_COUNT))." \
+		     "Please make sure all LIBBPF_API symbols are"	 \
+		     "versioned in $(VERSION_SCRIPT)." >&2;		 \
+		$(HOSTREADELF) -s --wide $(BPF_IN_SHARED) |		 \
+		    cut -d "@" -f1 | sed 's/_v[0-9]_[0-9]_[0-9].*//' |	 \
+		    sed 's/\[.*\]//' |					 \
+		    awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'|  \
+		    sort -u > $(OUTPUT)libbpf_global_syms.tmp;		 \
+		$(HOSTREADELF) --dyn-syms --wide $(OUTPUT)libbpf.so |	 \
+		    sed 's/\[.*\]//' |					 \
+		    awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}'|  \
+		    grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 |		 \
+		    sort -u > $(OUTPUT)libbpf_versioned_syms.tmp; 	 \
+		diff -u $(OUTPUT)libbpf_global_syms.tmp			 \
+		     $(OUTPUT)libbpf_versioned_syms.tmp;		 \
+		rm $(OUTPUT)libbpf_global_syms.tmp			 \
+		   $(OUTPUT)libbpf_versioned_syms.tmp;			 \
+		exit 1;							 \
+	fi
+
+HDR_MAJ_VERSION := $(shell grep -oE '^$(pound)define LIBBPF_MAJOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3)
+HDR_MIN_VERSION := $(shell grep -oE '^$(pound)define LIBBPF_MINOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3)
+
+check_version: $(VERSION_SCRIPT) libbpf_version.h
+	@if [ "$(HDR_MAJ_VERSION)" != "$(LIBBPF_MAJOR_VERSION)" ]; then        \
+		echo "Error: libbpf major version mismatch detected: "	       \
+		     "'$(HDR_MAJ_VERSION)' != '$(LIBBPF_MAJOR_VERSION)'" >&2;  \
+		exit 1;							       \
+	fi
+	@if [ "$(HDR_MIN_VERSION)" != "$(LIBBPF_MINOR_VERSION)" ]; then	       \
+		echo "Error: libbpf minor version mismatch detected: "	       \
+		     "'$(HDR_MIN_VERSION)' != '$(LIBBPF_MINOR_VERSION)'" >&2;  \
+		exit 1;							       \
+	fi
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then		\
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1';	\
+	fi
+endef
+
+define do_install
+	if [ ! -d '$(DESTDIR_SQ)$2' ]; then		\
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2';	\
+	fi;						\
+	$(INSTALL) $(if $3,-m $3,) $1 '$(DESTDIR_SQ)$2'
+endef
+
+install_lib: all_cmd
+	$(call QUIET_INSTALL, $(LIB_TARGET)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ)
+
+SRC_HDRS := bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h	     \
+	    bpf_helpers.h bpf_tracing.h bpf_endian.h bpf_core_read.h	     \
+	    skel_internal.h libbpf_version.h usdt.bpf.h
+GEN_HDRS := $(BPF_GENERATED)
+
+INSTALL_PFX := $(DESTDIR)$(prefix)/include/bpf
+INSTALL_SRC_HDRS := $(addprefix $(INSTALL_PFX)/, $(SRC_HDRS))
+INSTALL_GEN_HDRS := $(addprefix $(INSTALL_PFX)/, $(notdir $(GEN_HDRS)))
+
+$(INSTALL_SRC_HDRS): $(INSTALL_PFX)/%.h: %.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(prefix)/include/bpf,644)
+
+$(INSTALL_GEN_HDRS): $(INSTALL_PFX)/%.h: $(OUTPUT)%.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(prefix)/include/bpf,644)
+
+install_headers: $(BPF_GENERATED) $(INSTALL_SRC_HDRS) $(INSTALL_GEN_HDRS)
+	$(call QUIET_INSTALL, libbpf_headers)
+
+install_pkgconfig: $(PC_FILE)
+	$(call QUIET_INSTALL, $(PC_FILE)) \
+		$(call do_install,$(PC_FILE),$(libdir_SQ)/pkgconfig,644)
+
+install: install_lib install_pkgconfig install_headers
+
+clean: fixdep-clean
+	$(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS)		     \
+		*~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_GENERATED)		     \
+		$(SHARED_OBJDIR) $(STATIC_OBJDIR)			     \
+		$(addprefix $(OUTPUT),					     \
+			    *.o *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) *.pc)
+
+PHONY += force cscope tags check check_abi check_version
+force:
+
+cscope:
+	ls *.c *.h > cscope.files
+	cscope -b -q -I $(srctree)/include -f cscope.out
+
+tags:
+	$(RM) -f TAGS tags
+	ls *.c *.h | xargs $(TAGS_PROG) -a
+
+# Declare the contents of the .PHONY variable as phony.  We keep that
+# information in a variable so we can use it in if_changed and friends.
+.PHONY: $(PHONY)
+
+# Delete partially updated (corrupted) files on error
+.DELETE_ON_ERROR:
+
+help:
+	@echo 'libbpf common targets:'
+	@echo '  HINT: use "V=1" to enable verbose build'
+	@echo '  all     - build libraries and pkgconfig'
+	@echo '  clean   - remove all generated files'
+	@echo '  check   - check ABI and version info'
+	@echo ''
+	@echo 'libbpf install targets:'
+	@echo '  HINT: use "prefix"(defaults to "/usr/local") or "DESTDIR" (defaults to "/")'
+	@echo '        to adjust target destination, e.g. "make prefix=/usr/local install"'
+	@echo '  install          - build and install all headers, libraries and pkgconfig'
+	@echo '  install_headers  - install only headers to include/bpf'
+	@echo ''
+	@echo 'libbpf make targets:'
+	@echo '  tags    - use ctags to make tag information for source code browsing'
+	@echo '  cscope  - use cscope to make interactive source code browsing database'
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
new file mode 100644
index 000000000..96819c082
--- /dev/null
+++ b/tools/lib/bpf/bpf.c
@@ -0,0 +1,1484 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * common eBPF ELF operations.
+ *
+ * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License (not later!)
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not,  see <http://www.gnu.org/licenses>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <memory.h>
+#include <unistd.h>
+#include <asm/unistd.h>
+#include <errno.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <limits.h>
+#include <sys/resource.h>
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+/*
+ * When building perf, unistd.h is overridden. __NR_bpf is
+ * required to be defined explicitly.
+ */
+#ifndef __NR_bpf
+# if defined(__i386__)
+#  define __NR_bpf 357
+# elif defined(__x86_64__)
+#  define __NR_bpf 321
+# elif defined(__aarch64__)
+#  define __NR_bpf 280
+# elif defined(__sparc__)
+#  define __NR_bpf 349
+# elif defined(__s390__)
+#  define __NR_bpf 351
+# elif defined(__arc__)
+#  define __NR_bpf 280
+# elif defined(__mips__) && defined(_ABIO32)
+#  define __NR_bpf 4355
+# elif defined(__mips__) && defined(_ABIN32)
+#  define __NR_bpf 6319
+# elif defined(__mips__) && defined(_ABI64)
+#  define __NR_bpf 5315
+# elif defined(__loongarch__)
+#  define __NR_bpf 280
+# else
+#  error __NR_bpf not defined. libbpf does not support your arch.
+# endif
+#endif
+
+static inline __u64 ptr_to_u64(const void *ptr)
+{
+	return (__u64) (unsigned long) ptr;
+}
+
+static inline int sys_bpf_ext(enum bpf_cmd cmd, union bpf_attr *attr,
+			      unsigned int size,
+			      struct bpf_common_attr *attr_common,
+			      unsigned int size_common)
+{
+	cmd = attr_common ? (cmd | BPF_COMMON_ATTRS) : (cmd & ~BPF_COMMON_ATTRS);
+	return syscall(__NR_bpf, cmd, attr, size, attr_common, size_common);
+}
+
+static inline int sys_bpf_ext_fd(enum bpf_cmd cmd, union bpf_attr *attr,
+				 unsigned int size,
+				 struct bpf_common_attr *attr_common,
+				 unsigned int size_common)
+{
+	int fd;
+
+	fd = sys_bpf_ext(cmd, attr, size, attr_common, size_common);
+	return ensure_good_fd(fd);
+}
+
+int probe_sys_bpf_ext(void)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, prog_token_fd);
+	union bpf_attr attr;
+	int fd;
+
+	memset(&attr, 0, attr_sz);
+	fd = syscall(__NR_bpf, BPF_PROG_LOAD | BPF_COMMON_ATTRS, &attr, attr_sz, NULL,
+		     sizeof(struct bpf_common_attr));
+	if (fd >= 0) {
+		close(fd);
+		return -EINVAL;
+	}
+	return errno == EFAULT ? 1 : 0;
+}
+
+static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
+			  unsigned int size)
+{
+	return syscall(__NR_bpf, cmd, attr, size);
+}
+
+static inline int sys_bpf_fd(enum bpf_cmd cmd, union bpf_attr *attr,
+			     unsigned int size)
+{
+	int fd;
+
+	fd = sys_bpf(cmd, attr, size);
+	return ensure_good_fd(fd);
+}
+
+int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts)
+{
+	int fd;
+
+	do {
+		fd = sys_bpf_fd(BPF_PROG_LOAD, attr, size);
+	} while (fd < 0 && errno == EAGAIN && --attempts > 0);
+
+	return fd;
+}
+
+/* Probe whether kernel switched from memlock-based (RLIMIT_MEMLOCK) to
+ * memcg-based memory accounting for BPF maps and progs. This was done in [0].
+ * We use the support for bpf_ktime_get_coarse_ns() helper, which was added in
+ * the same 5.11 Linux release ([1]), to detect memcg-based accounting for BPF.
+ *
+ *   [0] https://lore.kernel.org/bpf/20201201215900.3569844-1-guro@fb.com/
+ *   [1] d05512618056 ("bpf: Add bpf_ktime_get_coarse_ns helper")
+ */
+int probe_memcg_account(int token_fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, prog_token_fd);
+	struct bpf_insn insns[] = {
+		BPF_EMIT_CALL(BPF_FUNC_ktime_get_coarse_ns),
+		BPF_EXIT_INSN(),
+	};
+	size_t insn_cnt = ARRAY_SIZE(insns);
+	union bpf_attr attr;
+	int prog_fd;
+
+	/* attempt loading freplace trying to use custom BTF */
+	memset(&attr, 0, attr_sz);
+	attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
+	attr.insns = ptr_to_u64(insns);
+	attr.insn_cnt = insn_cnt;
+	attr.license = ptr_to_u64("GPL");
+	attr.prog_token_fd = token_fd;
+	if (token_fd)
+		attr.prog_flags |= BPF_F_TOKEN_FD;
+
+	prog_fd = sys_bpf_fd(BPF_PROG_LOAD, &attr, attr_sz);
+	if (prog_fd >= 0) {
+		close(prog_fd);
+		return 1;
+	}
+	return 0;
+}
+
+static bool memlock_bumped;
+static rlim_t memlock_rlim = RLIM_INFINITY;
+
+int libbpf_set_memlock_rlim(size_t memlock_bytes)
+{
+	if (memlock_bumped)
+		return libbpf_err(-EBUSY);
+
+	memlock_rlim = memlock_bytes;
+	return 0;
+}
+
+int bump_rlimit_memlock(void)
+{
+	struct rlimit rlim;
+
+	/* if kernel supports memcg-based accounting, skip bumping RLIMIT_MEMLOCK */
+	if (memlock_bumped || feat_supported(NULL, FEAT_MEMCG_ACCOUNT))
+		return 0;
+
+	memlock_bumped = true;
+
+	/* zero memlock_rlim disables auto-bumping RLIMIT_MEMLOCK */
+	if (memlock_rlim == 0)
+		return 0;
+
+	rlim.rlim_cur = rlim.rlim_max = memlock_rlim;
+	if (setrlimit(RLIMIT_MEMLOCK, &rlim))
+		return -errno;
+
+	return 0;
+}
+
+int bpf_map_create(enum bpf_map_type map_type,
+		   const char *map_name,
+		   __u32 key_size,
+		   __u32 value_size,
+		   __u32 max_entries,
+		   const struct bpf_map_create_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, excl_prog_hash_size);
+	const size_t attr_common_sz = sizeof(struct bpf_common_attr);
+	struct bpf_common_attr attr_common;
+	struct bpf_log_opts *log_opts;
+	union bpf_attr attr;
+	int fd;
+
+	bump_rlimit_memlock();
+
+	memset(&attr, 0, attr_sz);
+
+	if (!OPTS_VALID(opts, bpf_map_create_opts))
+		return libbpf_err(-EINVAL);
+
+	attr.map_type = map_type;
+	if (map_name && feat_supported(NULL, FEAT_PROG_NAME))
+		libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name));
+	attr.key_size = key_size;
+	attr.value_size = value_size;
+	attr.max_entries = max_entries;
+
+	attr.btf_fd = OPTS_GET(opts, btf_fd, 0);
+	attr.btf_key_type_id = OPTS_GET(opts, btf_key_type_id, 0);
+	attr.btf_value_type_id = OPTS_GET(opts, btf_value_type_id, 0);
+	attr.btf_vmlinux_value_type_id = OPTS_GET(opts, btf_vmlinux_value_type_id, 0);
+	attr.value_type_btf_obj_fd = OPTS_GET(opts, value_type_btf_obj_fd, 0);
+
+	attr.inner_map_fd = OPTS_GET(opts, inner_map_fd, 0);
+	attr.map_flags = OPTS_GET(opts, map_flags, 0);
+	attr.map_extra = OPTS_GET(opts, map_extra, 0);
+	attr.numa_node = OPTS_GET(opts, numa_node, 0);
+	attr.map_ifindex = OPTS_GET(opts, map_ifindex, 0);
+
+	attr.map_token_fd = OPTS_GET(opts, token_fd, 0);
+	attr.excl_prog_hash = ptr_to_u64(OPTS_GET(opts, excl_prog_hash, NULL));
+	attr.excl_prog_hash_size = OPTS_GET(opts, excl_prog_hash_size, 0);
+
+	log_opts = OPTS_GET(opts, log_opts, NULL);
+	if (!OPTS_VALID(log_opts, bpf_log_opts))
+		return libbpf_err(-EINVAL);
+
+	if (log_opts && feat_supported(NULL, FEAT_BPF_SYSCALL_COMMON_ATTRS)) {
+		memset(&attr_common, 0, attr_common_sz);
+		attr_common.log_buf = ptr_to_u64(OPTS_GET(log_opts, buf, NULL));
+		attr_common.log_size = OPTS_GET(log_opts, size, 0);
+		attr_common.log_level = OPTS_GET(log_opts, level, 0);
+		fd = sys_bpf_ext_fd(BPF_MAP_CREATE, &attr, attr_sz, &attr_common, attr_common_sz);
+		OPTS_SET(log_opts, true_size, attr_common.log_true_size);
+	} else {
+		fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
+		OPTS_SET(log_opts, true_size, 0);
+	}
+	return libbpf_err_errno(fd);
+}
+
+static void *
+alloc_zero_tailing_info(const void *orecord, __u32 cnt,
+			__u32 actual_rec_size, __u32 expected_rec_size)
+{
+	__u64 info_len = (__u64)actual_rec_size * cnt;
+	void *info, *nrecord;
+	int i;
+
+	info = malloc(info_len);
+	if (!info)
+		return NULL;
+
+	/* zero out bytes kernel does not understand */
+	nrecord = info;
+	for (i = 0; i < cnt; i++) {
+		memcpy(nrecord, orecord, expected_rec_size);
+		memset(nrecord + expected_rec_size, 0,
+		       actual_rec_size - expected_rec_size);
+		orecord += actual_rec_size;
+		nrecord += actual_rec_size;
+	}
+
+	return info;
+}
+
+int bpf_prog_load(enum bpf_prog_type prog_type,
+		  const char *prog_name, const char *license,
+		  const struct bpf_insn *insns, size_t insn_cnt,
+		  struct bpf_prog_load_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, keyring_id);
+	void *finfo = NULL, *linfo = NULL;
+	const char *func_info, *line_info;
+	__u32 log_size, log_level, attach_prog_fd, attach_btf_obj_fd;
+	__u32 func_info_rec_size, line_info_rec_size;
+	int fd, attempts;
+	union bpf_attr attr;
+	char *log_buf;
+
+	bump_rlimit_memlock();
+
+	if (!OPTS_VALID(opts, bpf_prog_load_opts))
+		return libbpf_err(-EINVAL);
+
+	attempts = OPTS_GET(opts, attempts, 0);
+	if (attempts < 0)
+		return libbpf_err(-EINVAL);
+	if (attempts == 0)
+		attempts = PROG_LOAD_ATTEMPTS;
+
+	memset(&attr, 0, attr_sz);
+
+	attr.prog_type = prog_type;
+	attr.expected_attach_type = OPTS_GET(opts, expected_attach_type, 0);
+
+	attr.prog_btf_fd = OPTS_GET(opts, prog_btf_fd, 0);
+	attr.prog_flags = OPTS_GET(opts, prog_flags, 0);
+	attr.prog_ifindex = OPTS_GET(opts, prog_ifindex, 0);
+	attr.kern_version = OPTS_GET(opts, kern_version, 0);
+	attr.prog_token_fd = OPTS_GET(opts, token_fd, 0);
+
+	if (prog_name && feat_supported(NULL, FEAT_PROG_NAME))
+		libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
+	attr.license = ptr_to_u64(license);
+
+	if (insn_cnt > UINT_MAX)
+		return libbpf_err(-E2BIG);
+
+	attr.insns = ptr_to_u64(insns);
+	attr.insn_cnt = (__u32)insn_cnt;
+
+	attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
+	attach_btf_obj_fd = OPTS_GET(opts, attach_btf_obj_fd, 0);
+
+	if (attach_prog_fd && attach_btf_obj_fd)
+		return libbpf_err(-EINVAL);
+
+	attr.attach_btf_id = OPTS_GET(opts, attach_btf_id, 0);
+	if (attach_prog_fd)
+		attr.attach_prog_fd = attach_prog_fd;
+	else
+		attr.attach_btf_obj_fd = attach_btf_obj_fd;
+
+	log_buf = OPTS_GET(opts, log_buf, NULL);
+	log_size = OPTS_GET(opts, log_size, 0);
+	log_level = OPTS_GET(opts, log_level, 0);
+
+	if (!!log_buf != !!log_size)
+		return libbpf_err(-EINVAL);
+
+	func_info_rec_size = OPTS_GET(opts, func_info_rec_size, 0);
+	func_info = OPTS_GET(opts, func_info, NULL);
+	attr.func_info_rec_size = func_info_rec_size;
+	attr.func_info = ptr_to_u64(func_info);
+	attr.func_info_cnt = OPTS_GET(opts, func_info_cnt, 0);
+
+	line_info_rec_size = OPTS_GET(opts, line_info_rec_size, 0);
+	line_info = OPTS_GET(opts, line_info, NULL);
+	attr.line_info_rec_size = line_info_rec_size;
+	attr.line_info = ptr_to_u64(line_info);
+	attr.line_info_cnt = OPTS_GET(opts, line_info_cnt, 0);
+
+	attr.fd_array = ptr_to_u64(OPTS_GET(opts, fd_array, NULL));
+	attr.fd_array_cnt = OPTS_GET(opts, fd_array_cnt, 0);
+
+	if (log_level) {
+		attr.log_buf = ptr_to_u64(log_buf);
+		attr.log_size = log_size;
+		attr.log_level = log_level;
+	}
+
+	fd = sys_bpf_prog_load(&attr, attr_sz, attempts);
+	OPTS_SET(opts, log_true_size, attr.log_true_size);
+	if (fd >= 0)
+		return fd;
+
+	/* After bpf_prog_load, the kernel may modify certain attributes
+	 * to give user space a hint how to deal with loading failure.
+	 * Check to see whether we can make some changes and load again.
+	 */
+	while (errno == E2BIG && (!finfo || !linfo)) {
+		if (!finfo && attr.func_info_cnt &&
+		    attr.func_info_rec_size < func_info_rec_size) {
+			/* try with corrected func info records */
+			finfo = alloc_zero_tailing_info(func_info,
+							attr.func_info_cnt,
+							func_info_rec_size,
+							attr.func_info_rec_size);
+			if (!finfo) {
+				errno = E2BIG;
+				goto done;
+			}
+
+			attr.func_info = ptr_to_u64(finfo);
+			attr.func_info_rec_size = func_info_rec_size;
+		} else if (!linfo && attr.line_info_cnt &&
+			   attr.line_info_rec_size < line_info_rec_size) {
+			linfo = alloc_zero_tailing_info(line_info,
+							attr.line_info_cnt,
+							line_info_rec_size,
+							attr.line_info_rec_size);
+			if (!linfo) {
+				errno = E2BIG;
+				goto done;
+			}
+
+			attr.line_info = ptr_to_u64(linfo);
+			attr.line_info_rec_size = line_info_rec_size;
+		} else {
+			break;
+		}
+
+		fd = sys_bpf_prog_load(&attr, attr_sz, attempts);
+		OPTS_SET(opts, log_true_size, attr.log_true_size);
+		if (fd >= 0)
+			goto done;
+	}
+
+	if (log_level == 0 && log_buf) {
+		/* log_level == 0 with non-NULL log_buf requires retrying on error
+		 * with log_level == 1 and log_buf/log_buf_size set, to get details of
+		 * failure
+		 */
+		attr.log_buf = ptr_to_u64(log_buf);
+		attr.log_size = log_size;
+		attr.log_level = 1;
+
+		fd = sys_bpf_prog_load(&attr, attr_sz, attempts);
+		OPTS_SET(opts, log_true_size, attr.log_true_size);
+	}
+done:
+	/* free() doesn't affect errno, so we don't need to restore it */
+	free(finfo);
+	free(linfo);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_map_update_elem(int fd, const void *key, const void *value,
+			__u64 flags)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.value = ptr_to_u64(value);
+	attr.flags = flags;
+
+	ret = sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_lookup_elem(int fd, const void *key, void *value)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.value = ptr_to_u64(value);
+
+	ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.value = ptr_to_u64(value);
+	attr.flags = flags;
+
+	ret = sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.value = ptr_to_u64(value);
+
+	ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_lookup_and_delete_elem_flags(int fd, const void *key, void *value, __u64 flags)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.value = ptr_to_u64(value);
+	attr.flags = flags;
+
+	ret = sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_delete_elem(int fd, const void *key)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+
+	ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_delete_elem_flags(int fd, const void *key, __u64 flags)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.flags = flags;
+
+	ret = sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_get_next_key(int fd, const void *key, void *next_key)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, next_key);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = ptr_to_u64(key);
+	attr.next_key = ptr_to_u64(next_key);
+
+	ret = sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_freeze(int fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, map_fd);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+
+	ret = sys_bpf(BPF_MAP_FREEZE, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+static int bpf_map_batch_common(int cmd, int fd, void  *in_batch,
+				void *out_batch, void *keys, void *values,
+				__u32 *count,
+				const struct bpf_map_batch_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, batch);
+	union bpf_attr attr;
+	int ret;
+
+	if (!OPTS_VALID(opts, bpf_map_batch_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.batch.map_fd = fd;
+	attr.batch.in_batch = ptr_to_u64(in_batch);
+	attr.batch.out_batch = ptr_to_u64(out_batch);
+	attr.batch.keys = ptr_to_u64(keys);
+	attr.batch.values = ptr_to_u64(values);
+	attr.batch.count = *count;
+	attr.batch.elem_flags  = OPTS_GET(opts, elem_flags, 0);
+	attr.batch.flags = OPTS_GET(opts, flags, 0);
+
+	ret = sys_bpf(cmd, &attr, attr_sz);
+	*count = attr.batch.count;
+
+	return libbpf_err_errno(ret);
+}
+
+int bpf_map_delete_batch(int fd, const void *keys, __u32 *count,
+			 const struct bpf_map_batch_opts *opts)
+{
+	return bpf_map_batch_common(BPF_MAP_DELETE_BATCH, fd, NULL,
+				    NULL, (void *)keys, NULL, count, opts);
+}
+
+int bpf_map_lookup_batch(int fd, void *in_batch, void *out_batch, void *keys,
+			 void *values, __u32 *count,
+			 const struct bpf_map_batch_opts *opts)
+{
+	return bpf_map_batch_common(BPF_MAP_LOOKUP_BATCH, fd, in_batch,
+				    out_batch, keys, values, count, opts);
+}
+
+int bpf_map_lookup_and_delete_batch(int fd, void *in_batch, void *out_batch,
+				    void *keys, void *values, __u32 *count,
+				    const struct bpf_map_batch_opts *opts)
+{
+	return bpf_map_batch_common(BPF_MAP_LOOKUP_AND_DELETE_BATCH,
+				    fd, in_batch, out_batch, keys, values,
+				    count, opts);
+}
+
+int bpf_map_update_batch(int fd, const void *keys, const void *values, __u32 *count,
+			 const struct bpf_map_batch_opts *opts)
+{
+	return bpf_map_batch_common(BPF_MAP_UPDATE_BATCH, fd, NULL, NULL,
+				    (void *)keys, (void *)values, count, opts);
+}
+
+int bpf_obj_pin_opts(int fd, const char *pathname, const struct bpf_obj_pin_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, path_fd);
+	union bpf_attr attr;
+	int ret;
+
+	if (!OPTS_VALID(opts, bpf_obj_pin_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.path_fd = OPTS_GET(opts, path_fd, 0);
+	attr.pathname = ptr_to_u64((void *)pathname);
+	attr.file_flags = OPTS_GET(opts, file_flags, 0);
+	attr.bpf_fd = fd;
+
+	ret = sys_bpf(BPF_OBJ_PIN, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_obj_pin(int fd, const char *pathname)
+{
+	return bpf_obj_pin_opts(fd, pathname, NULL);
+}
+
+int bpf_obj_get(const char *pathname)
+{
+	return bpf_obj_get_opts(pathname, NULL);
+}
+
+int bpf_obj_get_opts(const char *pathname, const struct bpf_obj_get_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, path_fd);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_obj_get_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.path_fd = OPTS_GET(opts, path_fd, 0);
+	attr.pathname = ptr_to_u64((void *)pathname);
+	attr.file_flags = OPTS_GET(opts, file_flags, 0);
+
+	fd = sys_bpf_fd(BPF_OBJ_GET, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
+		    unsigned int flags)
+{
+	DECLARE_LIBBPF_OPTS(bpf_prog_attach_opts, opts,
+		.flags = flags,
+	);
+
+	return bpf_prog_attach_opts(prog_fd, target_fd, type, &opts);
+}
+
+int bpf_prog_attach_opts(int prog_fd, int target, enum bpf_attach_type type,
+			 const struct bpf_prog_attach_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, expected_revision);
+	__u32 relative_id, flags;
+	int ret, relative_fd;
+	union bpf_attr attr;
+
+	if (!OPTS_VALID(opts, bpf_prog_attach_opts))
+		return libbpf_err(-EINVAL);
+
+	relative_id = OPTS_GET(opts, relative_id, 0);
+	relative_fd = OPTS_GET(opts, relative_fd, 0);
+	flags = OPTS_GET(opts, flags, 0);
+
+	/* validate we don't have unexpected combinations of non-zero fields */
+	if (relative_fd && relative_id)
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.target_fd		= target;
+	attr.attach_bpf_fd	= prog_fd;
+	attr.attach_type	= type;
+	attr.replace_bpf_fd	= OPTS_GET(opts, replace_fd, 0);
+	attr.expected_revision	= OPTS_GET(opts, expected_revision, 0);
+
+	if (relative_id) {
+		attr.attach_flags = flags | BPF_F_ID;
+		attr.relative_id  = relative_id;
+	} else {
+		attr.attach_flags = flags;
+		attr.relative_fd  = relative_fd;
+	}
+
+	ret = sys_bpf(BPF_PROG_ATTACH, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_prog_detach_opts(int prog_fd, int target, enum bpf_attach_type type,
+			 const struct bpf_prog_detach_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, expected_revision);
+	__u32 relative_id, flags;
+	int ret, relative_fd;
+	union bpf_attr attr;
+
+	if (!OPTS_VALID(opts, bpf_prog_detach_opts))
+		return libbpf_err(-EINVAL);
+
+	relative_id = OPTS_GET(opts, relative_id, 0);
+	relative_fd = OPTS_GET(opts, relative_fd, 0);
+	flags = OPTS_GET(opts, flags, 0);
+
+	/* validate we don't have unexpected combinations of non-zero fields */
+	if (relative_fd && relative_id)
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.target_fd		= target;
+	attr.attach_bpf_fd	= prog_fd;
+	attr.attach_type	= type;
+	attr.expected_revision	= OPTS_GET(opts, expected_revision, 0);
+
+	if (relative_id) {
+		attr.attach_flags = flags | BPF_F_ID;
+		attr.relative_id  = relative_id;
+	} else {
+		attr.attach_flags = flags;
+		attr.relative_fd  = relative_fd;
+	}
+
+	ret = sys_bpf(BPF_PROG_DETACH, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
+{
+	return bpf_prog_detach_opts(0, target_fd, type, NULL);
+}
+
+int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)
+{
+	return bpf_prog_detach_opts(prog_fd, target_fd, type, NULL);
+}
+
+int bpf_link_create(int prog_fd, int target_fd,
+		    enum bpf_attach_type attach_type,
+		    const struct bpf_link_create_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, link_create);
+	__u32 target_btf_id, iter_info_len, relative_id;
+	int fd, err, relative_fd;
+	union bpf_attr attr;
+
+	if (!OPTS_VALID(opts, bpf_link_create_opts))
+		return libbpf_err(-EINVAL);
+
+	iter_info_len = OPTS_GET(opts, iter_info_len, 0);
+	target_btf_id = OPTS_GET(opts, target_btf_id, 0);
+
+	/* validate we don't have unexpected combinations of non-zero fields */
+	if (iter_info_len || target_btf_id) {
+		if (iter_info_len && target_btf_id)
+			return libbpf_err(-EINVAL);
+		if (!OPTS_ZEROED(opts, target_btf_id))
+			return libbpf_err(-EINVAL);
+	}
+
+	memset(&attr, 0, attr_sz);
+	attr.link_create.prog_fd = prog_fd;
+	attr.link_create.target_fd = target_fd;
+	attr.link_create.attach_type = attach_type;
+	attr.link_create.flags = OPTS_GET(opts, flags, 0);
+
+	if (target_btf_id) {
+		attr.link_create.target_btf_id = target_btf_id;
+		goto proceed;
+	}
+
+	switch (attach_type) {
+	case BPF_TRACE_ITER:
+		attr.link_create.iter_info = ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0));
+		attr.link_create.iter_info_len = iter_info_len;
+		break;
+	case BPF_PERF_EVENT:
+		attr.link_create.perf_event.bpf_cookie = OPTS_GET(opts, perf_event.bpf_cookie, 0);
+		if (!OPTS_ZEROED(opts, perf_event))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_TRACE_KPROBE_MULTI:
+	case BPF_TRACE_KPROBE_SESSION:
+		attr.link_create.kprobe_multi.flags = OPTS_GET(opts, kprobe_multi.flags, 0);
+		attr.link_create.kprobe_multi.cnt = OPTS_GET(opts, kprobe_multi.cnt, 0);
+		attr.link_create.kprobe_multi.syms = ptr_to_u64(OPTS_GET(opts, kprobe_multi.syms, 0));
+		attr.link_create.kprobe_multi.addrs = ptr_to_u64(OPTS_GET(opts, kprobe_multi.addrs, 0));
+		attr.link_create.kprobe_multi.cookies = ptr_to_u64(OPTS_GET(opts, kprobe_multi.cookies, 0));
+		if (!OPTS_ZEROED(opts, kprobe_multi))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_TRACE_UPROBE_MULTI:
+	case BPF_TRACE_UPROBE_SESSION:
+		attr.link_create.uprobe_multi.flags = OPTS_GET(opts, uprobe_multi.flags, 0);
+		attr.link_create.uprobe_multi.cnt = OPTS_GET(opts, uprobe_multi.cnt, 0);
+		attr.link_create.uprobe_multi.path = ptr_to_u64(OPTS_GET(opts, uprobe_multi.path, 0));
+		attr.link_create.uprobe_multi.offsets = ptr_to_u64(OPTS_GET(opts, uprobe_multi.offsets, 0));
+		attr.link_create.uprobe_multi.ref_ctr_offsets = ptr_to_u64(OPTS_GET(opts, uprobe_multi.ref_ctr_offsets, 0));
+		attr.link_create.uprobe_multi.cookies = ptr_to_u64(OPTS_GET(opts, uprobe_multi.cookies, 0));
+		attr.link_create.uprobe_multi.pid = OPTS_GET(opts, uprobe_multi.pid, 0);
+		attr.link_create.uprobe_multi.path_fd = OPTS_GET(opts, uprobe_multi.path_fd, 0);
+		if (!OPTS_ZEROED(opts, uprobe_multi))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_TRACE_FENTRY_MULTI:
+	case BPF_TRACE_FEXIT_MULTI:
+	case BPF_TRACE_FSESSION_MULTI:
+		attr.link_create.tracing_multi.ids = ptr_to_u64(OPTS_GET(opts, tracing_multi.ids, 0));
+		attr.link_create.tracing_multi.cookies = ptr_to_u64(OPTS_GET(opts, tracing_multi.cookies, 0));
+		attr.link_create.tracing_multi.cnt = OPTS_GET(opts, tracing_multi.cnt, 0);
+		if (!OPTS_ZEROED(opts, tracing_multi))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_TRACE_RAW_TP:
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+	case BPF_MODIFY_RETURN:
+	case BPF_TRACE_FSESSION:
+	case BPF_LSM_MAC:
+		attr.link_create.tracing.cookie = OPTS_GET(opts, tracing.cookie, 0);
+		if (!OPTS_ZEROED(opts, tracing))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_NETFILTER:
+		attr.link_create.netfilter.pf = OPTS_GET(opts, netfilter.pf, 0);
+		attr.link_create.netfilter.hooknum = OPTS_GET(opts, netfilter.hooknum, 0);
+		attr.link_create.netfilter.priority = OPTS_GET(opts, netfilter.priority, 0);
+		attr.link_create.netfilter.flags = OPTS_GET(opts, netfilter.flags, 0);
+		if (!OPTS_ZEROED(opts, netfilter))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_TCX_INGRESS:
+	case BPF_TCX_EGRESS:
+		relative_fd = OPTS_GET(opts, tcx.relative_fd, 0);
+		relative_id = OPTS_GET(opts, tcx.relative_id, 0);
+		if (relative_fd && relative_id)
+			return libbpf_err(-EINVAL);
+		if (relative_id) {
+			attr.link_create.tcx.relative_id = relative_id;
+			attr.link_create.flags |= BPF_F_ID;
+		} else {
+			attr.link_create.tcx.relative_fd = relative_fd;
+		}
+		attr.link_create.tcx.expected_revision = OPTS_GET(opts, tcx.expected_revision, 0);
+		if (!OPTS_ZEROED(opts, tcx))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_NETKIT_PRIMARY:
+	case BPF_NETKIT_PEER:
+		relative_fd = OPTS_GET(opts, netkit.relative_fd, 0);
+		relative_id = OPTS_GET(opts, netkit.relative_id, 0);
+		if (relative_fd && relative_id)
+			return libbpf_err(-EINVAL);
+		if (relative_id) {
+			attr.link_create.netkit.relative_id = relative_id;
+			attr.link_create.flags |= BPF_F_ID;
+		} else {
+			attr.link_create.netkit.relative_fd = relative_fd;
+		}
+		attr.link_create.netkit.expected_revision = OPTS_GET(opts, netkit.expected_revision, 0);
+		if (!OPTS_ZEROED(opts, netkit))
+			return libbpf_err(-EINVAL);
+		break;
+	case BPF_CGROUP_INET_INGRESS:
+	case BPF_CGROUP_INET_EGRESS:
+	case BPF_CGROUP_INET_SOCK_CREATE:
+	case BPF_CGROUP_INET_SOCK_RELEASE:
+	case BPF_CGROUP_INET4_BIND:
+	case BPF_CGROUP_INET6_BIND:
+	case BPF_CGROUP_INET4_POST_BIND:
+	case BPF_CGROUP_INET6_POST_BIND:
+	case BPF_CGROUP_INET4_CONNECT:
+	case BPF_CGROUP_INET6_CONNECT:
+	case BPF_CGROUP_UNIX_CONNECT:
+	case BPF_CGROUP_INET4_GETPEERNAME:
+	case BPF_CGROUP_INET6_GETPEERNAME:
+	case BPF_CGROUP_UNIX_GETPEERNAME:
+	case BPF_CGROUP_INET4_GETSOCKNAME:
+	case BPF_CGROUP_INET6_GETSOCKNAME:
+	case BPF_CGROUP_UNIX_GETSOCKNAME:
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
+	case BPF_CGROUP_UNIX_SENDMSG:
+	case BPF_CGROUP_UDP4_RECVMSG:
+	case BPF_CGROUP_UDP6_RECVMSG:
+	case BPF_CGROUP_UNIX_RECVMSG:
+	case BPF_CGROUP_SOCK_OPS:
+	case BPF_CGROUP_DEVICE:
+	case BPF_CGROUP_SYSCTL:
+	case BPF_CGROUP_GETSOCKOPT:
+	case BPF_CGROUP_SETSOCKOPT:
+	case BPF_LSM_CGROUP:
+		relative_fd = OPTS_GET(opts, cgroup.relative_fd, 0);
+		relative_id = OPTS_GET(opts, cgroup.relative_id, 0);
+		if (relative_fd && relative_id)
+			return libbpf_err(-EINVAL);
+		if (relative_id) {
+			attr.link_create.cgroup.relative_id = relative_id;
+			attr.link_create.flags |= BPF_F_ID;
+		} else {
+			attr.link_create.cgroup.relative_fd = relative_fd;
+		}
+		attr.link_create.cgroup.expected_revision =
+			OPTS_GET(opts, cgroup.expected_revision, 0);
+		if (!OPTS_ZEROED(opts, cgroup))
+			return libbpf_err(-EINVAL);
+		break;
+	default:
+		if (!OPTS_ZEROED(opts, flags))
+			return libbpf_err(-EINVAL);
+		break;
+	}
+proceed:
+	fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, attr_sz);
+	if (fd >= 0)
+		return fd;
+	/* we'll get EINVAL if LINK_CREATE doesn't support attaching fentry
+	 * and other similar programs
+	 */
+	err = -errno;
+	if (err != -EINVAL)
+		return libbpf_err(err);
+
+	/* if user used features not supported by
+	 * BPF_RAW_TRACEPOINT_OPEN command, then just give up immediately
+	 */
+	if (attr.link_create.target_fd || attr.link_create.target_btf_id)
+		return libbpf_err(err);
+	if (!OPTS_ZEROED(opts, sz))
+		return libbpf_err(err);
+
+	/* otherwise, for few select kinds of programs that can be
+	 * attached using BPF_RAW_TRACEPOINT_OPEN command, try that as
+	 * a fallback for older kernels
+	 */
+	switch (attach_type) {
+	case BPF_TRACE_RAW_TP:
+	case BPF_LSM_MAC:
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+	case BPF_MODIFY_RETURN:
+		return bpf_raw_tracepoint_open(NULL, prog_fd);
+	default:
+		return libbpf_err(err);
+	}
+}
+
+int bpf_link_detach(int link_fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, link_detach);
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.link_detach.link_fd = link_fd;
+
+	ret = sys_bpf(BPF_LINK_DETACH, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_link_update(int link_fd, int new_prog_fd,
+		    const struct bpf_link_update_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, link_update);
+	union bpf_attr attr;
+	int ret;
+
+	if (!OPTS_VALID(opts, bpf_link_update_opts))
+		return libbpf_err(-EINVAL);
+
+	if (OPTS_GET(opts, old_prog_fd, 0) && OPTS_GET(opts, old_map_fd, 0))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.link_update.link_fd = link_fd;
+	attr.link_update.new_prog_fd = new_prog_fd;
+	attr.link_update.flags = OPTS_GET(opts, flags, 0);
+	if (OPTS_GET(opts, old_prog_fd, 0))
+		attr.link_update.old_prog_fd = OPTS_GET(opts, old_prog_fd, 0);
+	else if (OPTS_GET(opts, old_map_fd, 0))
+		attr.link_update.old_map_fd = OPTS_GET(opts, old_map_fd, 0);
+
+	ret = sys_bpf(BPF_LINK_UPDATE, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_iter_create(int link_fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, iter_create);
+	union bpf_attr attr;
+	int fd;
+
+	memset(&attr, 0, attr_sz);
+	attr.iter_create.link_fd = link_fd;
+
+	fd = sys_bpf_fd(BPF_ITER_CREATE, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_prog_query_opts(int target, enum bpf_attach_type type,
+			struct bpf_prog_query_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, query);
+	union bpf_attr attr;
+	int ret;
+
+	if (!OPTS_VALID(opts, bpf_prog_query_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.query.target_fd		= target;
+	attr.query.attach_type		= type;
+	attr.query.query_flags		= OPTS_GET(opts, query_flags, 0);
+	attr.query.count		= OPTS_GET(opts, count, 0);
+	attr.query.prog_ids		= ptr_to_u64(OPTS_GET(opts, prog_ids, NULL));
+	attr.query.link_ids		= ptr_to_u64(OPTS_GET(opts, link_ids, NULL));
+	attr.query.prog_attach_flags	= ptr_to_u64(OPTS_GET(opts, prog_attach_flags, NULL));
+	attr.query.link_attach_flags	= ptr_to_u64(OPTS_GET(opts, link_attach_flags, NULL));
+
+	ret = sys_bpf(BPF_PROG_QUERY, &attr, attr_sz);
+
+	OPTS_SET(opts, attach_flags, attr.query.attach_flags);
+	OPTS_SET(opts, revision, attr.query.revision);
+	OPTS_SET(opts, count, attr.query.count);
+
+	return libbpf_err_errno(ret);
+}
+
+int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
+		   __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt)
+{
+	LIBBPF_OPTS(bpf_prog_query_opts, opts);
+	int ret;
+
+	opts.query_flags = query_flags;
+	opts.prog_ids = prog_ids;
+	opts.prog_cnt = *prog_cnt;
+
+	ret = bpf_prog_query_opts(target_fd, type, &opts);
+
+	if (attach_flags)
+		*attach_flags = opts.attach_flags;
+	*prog_cnt = opts.prog_cnt;
+
+	return libbpf_err_errno(ret);
+}
+
+int bpf_prog_test_run_opts(int prog_fd, struct bpf_test_run_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, test);
+	union bpf_attr attr;
+	int ret;
+
+	if (!OPTS_VALID(opts, bpf_test_run_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.test.prog_fd = prog_fd;
+	attr.test.batch_size = OPTS_GET(opts, batch_size, 0);
+	attr.test.cpu = OPTS_GET(opts, cpu, 0);
+	attr.test.flags = OPTS_GET(opts, flags, 0);
+	attr.test.repeat = OPTS_GET(opts, repeat, 0);
+	attr.test.duration = OPTS_GET(opts, duration, 0);
+	attr.test.ctx_size_in = OPTS_GET(opts, ctx_size_in, 0);
+	attr.test.ctx_size_out = OPTS_GET(opts, ctx_size_out, 0);
+	attr.test.data_size_in = OPTS_GET(opts, data_size_in, 0);
+	attr.test.data_size_out = OPTS_GET(opts, data_size_out, 0);
+	attr.test.ctx_in = ptr_to_u64(OPTS_GET(opts, ctx_in, NULL));
+	attr.test.ctx_out = ptr_to_u64(OPTS_GET(opts, ctx_out, NULL));
+	attr.test.data_in = ptr_to_u64(OPTS_GET(opts, data_in, NULL));
+	attr.test.data_out = ptr_to_u64(OPTS_GET(opts, data_out, NULL));
+
+	ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, attr_sz);
+
+	OPTS_SET(opts, data_size_out, attr.test.data_size_out);
+	OPTS_SET(opts, ctx_size_out, attr.test.ctx_size_out);
+	OPTS_SET(opts, duration, attr.test.duration);
+	OPTS_SET(opts, retval, attr.test.retval);
+
+	return libbpf_err_errno(ret);
+}
+
+static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
+	union bpf_attr attr;
+	int err;
+
+	memset(&attr, 0, attr_sz);
+	attr.start_id = start_id;
+
+	err = sys_bpf(cmd, &attr, attr_sz);
+	if (!err)
+		*next_id = attr.next_id;
+
+	return libbpf_err_errno(err);
+}
+
+int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id)
+{
+	return bpf_obj_get_next_id(start_id, next_id, BPF_PROG_GET_NEXT_ID);
+}
+
+int bpf_map_get_next_id(__u32 start_id, __u32 *next_id)
+{
+	return bpf_obj_get_next_id(start_id, next_id, BPF_MAP_GET_NEXT_ID);
+}
+
+int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id)
+{
+	return bpf_obj_get_next_id(start_id, next_id, BPF_BTF_GET_NEXT_ID);
+}
+
+int bpf_link_get_next_id(__u32 start_id, __u32 *next_id)
+{
+	return bpf_obj_get_next_id(start_id, next_id, BPF_LINK_GET_NEXT_ID);
+}
+
+int bpf_prog_get_fd_by_id_opts(__u32 id,
+			       const struct bpf_get_fd_by_id_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_get_fd_by_id_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.prog_id = id;
+	attr.open_flags = OPTS_GET(opts, open_flags, 0);
+
+	fd = sys_bpf_fd(BPF_PROG_GET_FD_BY_ID, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_prog_get_fd_by_id(__u32 id)
+{
+	return bpf_prog_get_fd_by_id_opts(id, NULL);
+}
+
+int bpf_map_get_fd_by_id_opts(__u32 id,
+			      const struct bpf_get_fd_by_id_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_get_fd_by_id_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.map_id = id;
+	attr.open_flags = OPTS_GET(opts, open_flags, 0);
+
+	fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_map_get_fd_by_id(__u32 id)
+{
+	return bpf_map_get_fd_by_id_opts(id, NULL);
+}
+
+int bpf_btf_get_fd_by_id_opts(__u32 id,
+			      const struct bpf_get_fd_by_id_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, fd_by_id_token_fd);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_get_fd_by_id_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.btf_id = id;
+	attr.open_flags = OPTS_GET(opts, open_flags, 0);
+	attr.fd_by_id_token_fd = OPTS_GET(opts, token_fd, 0);
+
+	fd = sys_bpf_fd(BPF_BTF_GET_FD_BY_ID, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_btf_get_fd_by_id(__u32 id)
+{
+	return bpf_btf_get_fd_by_id_opts(id, NULL);
+}
+
+int bpf_link_get_fd_by_id_opts(__u32 id,
+			       const struct bpf_get_fd_by_id_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, open_flags);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_get_fd_by_id_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.link_id = id;
+	attr.open_flags = OPTS_GET(opts, open_flags, 0);
+
+	fd = sys_bpf_fd(BPF_LINK_GET_FD_BY_ID, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_link_get_fd_by_id(__u32 id)
+{
+	return bpf_link_get_fd_by_id_opts(id, NULL);
+}
+
+int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, info);
+	union bpf_attr attr;
+	int err;
+
+	memset(&attr, 0, attr_sz);
+	attr.info.bpf_fd = bpf_fd;
+	attr.info.info_len = *info_len;
+	attr.info.info = ptr_to_u64(info);
+
+	err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, attr_sz);
+	if (!err)
+		*info_len = attr.info.info_len;
+	return libbpf_err_errno(err);
+}
+
+int bpf_prog_get_info_by_fd(int prog_fd, struct bpf_prog_info *info, __u32 *info_len)
+{
+	return bpf_obj_get_info_by_fd(prog_fd, info, info_len);
+}
+
+int bpf_map_get_info_by_fd(int map_fd, struct bpf_map_info *info, __u32 *info_len)
+{
+	return bpf_obj_get_info_by_fd(map_fd, info, info_len);
+}
+
+int bpf_btf_get_info_by_fd(int btf_fd, struct bpf_btf_info *info, __u32 *info_len)
+{
+	return bpf_obj_get_info_by_fd(btf_fd, info, info_len);
+}
+
+int bpf_link_get_info_by_fd(int link_fd, struct bpf_link_info *info, __u32 *info_len)
+{
+	return bpf_obj_get_info_by_fd(link_fd, info, info_len);
+}
+
+int bpf_raw_tracepoint_open_opts(int prog_fd, struct bpf_raw_tp_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, raw_tracepoint);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_raw_tp_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.raw_tracepoint.prog_fd = prog_fd;
+	attr.raw_tracepoint.name = ptr_to_u64(OPTS_GET(opts, tp_name, NULL));
+	attr.raw_tracepoint.cookie = OPTS_GET(opts, cookie, 0);
+
+	fd = sys_bpf_fd(BPF_RAW_TRACEPOINT_OPEN, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_raw_tracepoint_open(const char *name, int prog_fd)
+{
+	LIBBPF_OPTS(bpf_raw_tp_opts, opts, .tp_name = name);
+
+	return bpf_raw_tracepoint_open_opts(prog_fd, &opts);
+}
+
+int bpf_btf_load(const void *btf_data, size_t btf_size, struct bpf_btf_load_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, btf_token_fd);
+	union bpf_attr attr;
+	char *log_buf;
+	size_t log_size;
+	__u32 log_level;
+	int fd;
+
+	bump_rlimit_memlock();
+
+	memset(&attr, 0, attr_sz);
+
+	if (!OPTS_VALID(opts, bpf_btf_load_opts))
+		return libbpf_err(-EINVAL);
+
+	log_buf = OPTS_GET(opts, log_buf, NULL);
+	log_size = OPTS_GET(opts, log_size, 0);
+	log_level = OPTS_GET(opts, log_level, 0);
+
+	if (log_size > UINT_MAX)
+		return libbpf_err(-EINVAL);
+	if (log_size && !log_buf)
+		return libbpf_err(-EINVAL);
+
+	attr.btf = ptr_to_u64(btf_data);
+	attr.btf_size = btf_size;
+
+	attr.btf_flags = OPTS_GET(opts, btf_flags, 0);
+	attr.btf_token_fd = OPTS_GET(opts, token_fd, 0);
+
+	/* log_level == 0 and log_buf != NULL means "try loading without
+	 * log_buf, but retry with log_buf and log_level=1 on error", which is
+	 * consistent across low-level and high-level BTF and program loading
+	 * APIs within libbpf and provides a sensible behavior in practice
+	 */
+	if (log_level) {
+		attr.btf_log_buf = ptr_to_u64(log_buf);
+		attr.btf_log_size = (__u32)log_size;
+		attr.btf_log_level = log_level;
+	}
+
+	fd = sys_bpf_fd(BPF_BTF_LOAD, &attr, attr_sz);
+	if (fd < 0 && log_buf && log_level == 0) {
+		attr.btf_log_buf = ptr_to_u64(log_buf);
+		attr.btf_log_size = (__u32)log_size;
+		attr.btf_log_level = 1;
+		fd = sys_bpf_fd(BPF_BTF_LOAD, &attr, attr_sz);
+	}
+
+	OPTS_SET(opts, log_true_size, attr.btf_log_true_size);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
+		      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
+		      __u64 *probe_addr)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, task_fd_query);
+	union bpf_attr attr;
+	int err;
+
+	memset(&attr, 0, attr_sz);
+	attr.task_fd_query.pid = pid;
+	attr.task_fd_query.fd = fd;
+	attr.task_fd_query.flags = flags;
+	attr.task_fd_query.buf = ptr_to_u64(buf);
+	attr.task_fd_query.buf_len = *buf_len;
+
+	err = sys_bpf(BPF_TASK_FD_QUERY, &attr, attr_sz);
+
+	*buf_len = attr.task_fd_query.buf_len;
+	*prog_id = attr.task_fd_query.prog_id;
+	*fd_type = attr.task_fd_query.fd_type;
+	*probe_offset = attr.task_fd_query.probe_offset;
+	*probe_addr = attr.task_fd_query.probe_addr;
+
+	return libbpf_err_errno(err);
+}
+
+int bpf_enable_stats(enum bpf_stats_type type)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, enable_stats);
+	union bpf_attr attr;
+	int fd;
+
+	memset(&attr, 0, attr_sz);
+	attr.enable_stats.type = type;
+
+	fd = sys_bpf_fd(BPF_ENABLE_STATS, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_prog_bind_map(int prog_fd, int map_fd,
+		      const struct bpf_prog_bind_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, prog_bind_map);
+	union bpf_attr attr;
+	int ret;
+
+	if (!OPTS_VALID(opts, bpf_prog_bind_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.prog_bind_map.prog_fd = prog_fd;
+	attr.prog_bind_map.map_fd = map_fd;
+	attr.prog_bind_map.flags = OPTS_GET(opts, flags, 0);
+
+	ret = sys_bpf(BPF_PROG_BIND_MAP, &attr, attr_sz);
+	return libbpf_err_errno(ret);
+}
+
+int bpf_token_create(int bpffs_fd, struct bpf_token_create_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, token_create);
+	union bpf_attr attr;
+	int fd;
+
+	if (!OPTS_VALID(opts, bpf_token_create_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.token_create.bpffs_fd = bpffs_fd;
+	attr.token_create.flags = OPTS_GET(opts, flags, 0);
+
+	fd = sys_bpf_fd(BPF_TOKEN_CREATE, &attr, attr_sz);
+	return libbpf_err_errno(fd);
+}
+
+int bpf_prog_stream_read(int prog_fd, __u32 stream_id, void *buf, __u32 buf_len,
+			 struct bpf_prog_stream_read_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, prog_stream_read);
+	union bpf_attr attr;
+	int err;
+
+	if (!OPTS_VALID(opts, bpf_prog_stream_read_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.prog_stream_read.stream_buf = ptr_to_u64(buf);
+	attr.prog_stream_read.stream_buf_len = buf_len;
+	attr.prog_stream_read.stream_id = stream_id;
+	attr.prog_stream_read.prog_fd = prog_fd;
+
+	err = sys_bpf(BPF_PROG_STREAM_READ_BY_FD, &attr, attr_sz);
+	return libbpf_err_errno(err);
+}
+
+int bpf_prog_assoc_struct_ops(int prog_fd, int map_fd,
+			      struct bpf_prog_assoc_struct_ops_opts *opts)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, prog_assoc_struct_ops);
+	union bpf_attr attr;
+	int err;
+
+	if (!OPTS_VALID(opts, bpf_prog_assoc_struct_ops_opts))
+		return libbpf_err(-EINVAL);
+
+	memset(&attr, 0, attr_sz);
+	attr.prog_assoc_struct_ops.map_fd = map_fd;
+	attr.prog_assoc_struct_ops.prog_fd = prog_fd;
+	attr.prog_assoc_struct_ops.flags = OPTS_GET(opts, flags, 0);
+
+	err = sys_bpf(BPF_PROG_ASSOC_STRUCT_OPS, &attr, attr_sz);
+	return libbpf_err_errno(err);
+}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
new file mode 100644
index 000000000..7534a593e
--- /dev/null
+++ b/tools/lib/bpf/bpf.h
@@ -0,0 +1,790 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * Common BPF ELF operations.
+ *
+ * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License (not later!)
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not,  see <http://www.gnu.org/licenses>
+ */
+#ifndef __LIBBPF_BPF_H
+#define __LIBBPF_BPF_H
+
+#include <linux/bpf.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "libbpf_common.h"
+#include "libbpf_legacy.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+LIBBPF_API int libbpf_set_memlock_rlim(size_t memlock_bytes);
+
+struct bpf_log_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	char *buf;
+	__u32 size;
+	__u32 level;
+	__u32 true_size; /* out parameter set by kernel */
+
+	size_t :0;
+};
+#define bpf_log_opts__last_field true_size
+
+struct bpf_map_create_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	__u32 btf_fd;
+	__u32 btf_key_type_id;
+	__u32 btf_value_type_id;
+	__u32 btf_vmlinux_value_type_id;
+
+	__u32 inner_map_fd;
+	__u32 map_flags;
+	__u64 map_extra;
+
+	__u32 numa_node;
+	__u32 map_ifindex;
+	__s32 value_type_btf_obj_fd;
+
+	__u32 token_fd;
+
+	const void *excl_prog_hash;
+	__u32 excl_prog_hash_size;
+
+	struct bpf_log_opts *log_opts;
+
+	size_t :0;
+};
+#define bpf_map_create_opts__last_field log_opts
+
+LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
+			      const char *map_name,
+			      __u32 key_size,
+			      __u32 value_size,
+			      __u32 max_entries,
+			      const struct bpf_map_create_opts *opts);
+
+struct bpf_prog_load_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	/* libbpf can retry BPF_PROG_LOAD command if bpf() syscall returns
+	 * -EAGAIN. This field determines how many attempts libbpf has to
+	 *  make. If not specified, libbpf will use default value of 5.
+	 */
+	int attempts;
+
+	enum bpf_attach_type expected_attach_type;
+	__u32 prog_btf_fd;
+	__u32 prog_flags;
+	__u32 prog_ifindex;
+	__u32 kern_version;
+
+	__u32 attach_btf_id;
+	__u32 attach_prog_fd;
+	__u32 attach_btf_obj_fd;
+
+	const int *fd_array;
+
+	/* .BTF.ext func info data */
+	const void *func_info;
+	__u32 func_info_cnt;
+	__u32 func_info_rec_size;
+
+	/* .BTF.ext line info data */
+	const void *line_info;
+	__u32 line_info_cnt;
+	__u32 line_info_rec_size;
+
+	/* verifier log options */
+	__u32 log_level;
+	__u32 log_size;
+	char *log_buf;
+	/* output: actual total log contents size (including terminating zero).
+	 * It could be both larger than original log_size (if log was
+	 * truncated), or smaller (if log buffer wasn't filled completely).
+	 * If kernel doesn't support this feature, log_size is left unchanged.
+	 */
+	__u32 log_true_size;
+	__u32 token_fd;
+
+	/* if set, provides the length of fd_array */
+	__u32 fd_array_cnt;
+	size_t :0;
+};
+#define bpf_prog_load_opts__last_field fd_array_cnt
+
+LIBBPF_API int bpf_prog_load(enum bpf_prog_type prog_type,
+			     const char *prog_name, const char *license,
+			     const struct bpf_insn *insns, size_t insn_cnt,
+			     struct bpf_prog_load_opts *opts);
+
+/* Flags to direct loading requirements */
+#define MAPS_RELAX_COMPAT	0x01
+
+/* Recommended log buffer size */
+#define BPF_LOG_BUF_SIZE (UINT32_MAX >> 8) /* verifier maximum in kernels <= 5.1 */
+
+struct bpf_btf_load_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	/* kernel log options */
+	char *log_buf;
+	__u32 log_level;
+	__u32 log_size;
+	/* output: actual total log contents size (including terminating zero).
+	 * It could be both larger than original log_size (if log was
+	 * truncated), or smaller (if log buffer wasn't filled completely).
+	 * If kernel doesn't support this feature, log_size is left unchanged.
+	 */
+	__u32 log_true_size;
+
+	__u32 btf_flags;
+	__u32 token_fd;
+	size_t :0;
+};
+#define bpf_btf_load_opts__last_field token_fd
+
+LIBBPF_API int bpf_btf_load(const void *btf_data, size_t btf_size,
+			    struct bpf_btf_load_opts *opts);
+
+LIBBPF_API int bpf_map_update_elem(int fd, const void *key, const void *value,
+				   __u64 flags);
+
+LIBBPF_API int bpf_map_lookup_elem(int fd, const void *key, void *value);
+LIBBPF_API int bpf_map_lookup_elem_flags(int fd, const void *key, void *value,
+					 __u64 flags);
+LIBBPF_API int bpf_map_lookup_and_delete_elem(int fd, const void *key,
+					      void *value);
+LIBBPF_API int bpf_map_lookup_and_delete_elem_flags(int fd, const void *key,
+						    void *value, __u64 flags);
+LIBBPF_API int bpf_map_delete_elem(int fd, const void *key);
+LIBBPF_API int bpf_map_delete_elem_flags(int fd, const void *key, __u64 flags);
+LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key);
+LIBBPF_API int bpf_map_freeze(int fd);
+
+struct bpf_map_batch_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u64 elem_flags;
+	__u64 flags;
+};
+#define bpf_map_batch_opts__last_field flags
+
+
+/**
+ * @brief **bpf_map_delete_batch()** allows for batch deletion of multiple
+ * elements in a BPF map.
+ *
+ * @param fd BPF map file descriptor
+ * @param keys pointer to an array of *count* keys
+ * @param count input and output parameter; on input **count** represents the
+ * number of  elements in the map to delete in batch;
+ * on output if a non-EFAULT error is returned, **count** represents the number of deleted
+ * elements if the output **count** value is not equal to the input **count** value
+ * If EFAULT is returned, **count** should not be trusted to be correct.
+ * @param opts options for configuring the way the batch deletion works
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_delete_batch(int fd, const void *keys,
+				    __u32 *count,
+				    const struct bpf_map_batch_opts *opts);
+
+/**
+ * @brief **bpf_map_lookup_batch()** allows for batch lookup of BPF map elements.
+ *
+ * The parameter *in_batch* is the address of the first element in the batch to
+ * read. *out_batch* is an output parameter that should be passed as *in_batch*
+ * to subsequent calls to **bpf_map_lookup_batch()**. NULL can be passed for
+ * *in_batch* to indicate that the batched lookup starts from the beginning of
+ * the map. Both *in_batch* and *out_batch* must point to memory large enough to
+ * hold a single key, except for maps of type **BPF_MAP_TYPE_{HASH, PERCPU_HASH,
+ * LRU_HASH, LRU_PERCPU_HASH}**, for which the memory size must be at
+ * least 4 bytes wide regardless of key size.
+ *
+ * The *keys* and *values* are output parameters which must point to memory large enough to
+ * hold *count* items based on the key and value size of the map *map_fd*. The *keys*
+ * buffer must be of *key_size* * *count*. The *values* buffer must be of
+ * *value_size* * *count*.
+ *
+ * @param fd BPF map file descriptor
+ * @param in_batch address of the first element in batch to read, can pass NULL to
+ * indicate that the batched lookup starts from the beginning of the map.
+ * @param out_batch output parameter that should be passed to next call as *in_batch*
+ * @param keys pointer to an array large enough for *count* keys
+ * @param values pointer to an array large enough for *count* values
+ * @param count input and output parameter; on input it's the number of elements
+ * in the map to read in batch; on output it's the number of elements that were
+ * successfully read.
+ * If a non-EFAULT error is returned, count will be set as the number of elements
+ * that were read before the error occurred.
+ * If EFAULT is returned, **count** should not be trusted to be correct.
+ * @param opts options for configuring the way the batch lookup works
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_lookup_batch(int fd, void *in_batch, void *out_batch,
+				    void *keys, void *values, __u32 *count,
+				    const struct bpf_map_batch_opts *opts);
+
+/**
+ * @brief **bpf_map_lookup_and_delete_batch()** allows for batch lookup and deletion
+ * of BPF map elements where each element is deleted after being retrieved.
+ *
+ * @param fd BPF map file descriptor
+ * @param in_batch address of the first element in batch to read, can pass NULL to
+ * get address of the first element in *out_batch*. If not NULL, must be large
+ * enough to hold a key. For **BPF_MAP_TYPE_{HASH, PERCPU_HASH, LRU_HASH,
+ * LRU_PERCPU_HASH}**, the memory size must be at least 4 bytes wide regardless
+ * of key size.
+ * @param out_batch output parameter that should be passed to next call as *in_batch*
+ * @param keys pointer to an array of *count* keys
+ * @param values pointer to an array large enough for *count* values
+ * @param count input and output parameter; on input it's the number of elements
+ * in the map to read and delete in batch; on output it represents the number of
+ * elements that were successfully read and deleted
+ * If a non-**EFAULT** error code is returned and if the output **count** value
+ * is not equal to the input **count** value, up to **count** elements may
+ * have been deleted.
+ * if **EFAULT** is returned up to *count* elements may have been deleted without
+ * being returned via the *keys* and *values* output parameters.
+ * @param opts options for configuring the way the batch lookup and delete works
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_lookup_and_delete_batch(int fd, void *in_batch,
+					void *out_batch, void *keys,
+					void *values, __u32 *count,
+					const struct bpf_map_batch_opts *opts);
+
+/**
+ * @brief **bpf_map_update_batch()** updates multiple elements in a map
+ * by specifying keys and their corresponding values.
+ *
+ * The *keys* and *values* parameters must point to memory large enough
+ * to hold *count* items based on the key and value size of the map.
+ *
+ * The *opts* parameter can be used to control how *bpf_map_update_batch()*
+ * should handle keys that either do or do not already exist in the map.
+ * In particular the *flags* parameter of *bpf_map_batch_opts* can be
+ * one of the following:
+ *
+ * Note that *count* is an input and output parameter, where on output it
+ * represents how many elements were successfully updated. Also note that if
+ * **EFAULT** then *count* should not be trusted to be correct.
+ *
+ * **BPF_ANY**
+ *    Create new elements or update existing.
+ *
+ * **BPF_NOEXIST**
+ *    Create new elements only if they do not exist.
+ *
+ * **BPF_EXIST**
+ *    Update existing elements.
+ *
+ * **BPF_F_LOCK**
+ *    Update spin_lock-ed map elements. This must be
+ *    specified if the map value contains a spinlock.
+ *
+ * **BPF_F_CPU**
+ *    As for percpu maps, update value on the specified CPU. And the cpu
+ *    info is embedded into the high 32 bits of **opts->elem_flags**.
+ *
+ * **BPF_F_ALL_CPUS**
+ *    As for percpu maps, update value across all CPUs. This flag cannot
+ *    be used with BPF_F_CPU at the same time.
+ *
+ * @param fd BPF map file descriptor
+ * @param keys pointer to an array of *count* keys
+ * @param values pointer to an array of *count* values
+ * @param count input and output parameter; on input it's the number of elements
+ * in the map to update in batch; on output if a non-EFAULT error is returned,
+ * **count** represents the number of updated elements if the output **count**
+ * value is not equal to the input **count** value.
+ * If EFAULT is returned, **count** should not be trusted to be correct.
+ * @param opts options for configuring the way the batch update works
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_update_batch(int fd, const void *keys, const void *values,
+				    __u32 *count,
+				    const struct bpf_map_batch_opts *opts);
+
+struct bpf_obj_pin_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	__u32 file_flags;
+	int path_fd;
+
+	size_t :0;
+};
+#define bpf_obj_pin_opts__last_field path_fd
+
+LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
+LIBBPF_API int bpf_obj_pin_opts(int fd, const char *pathname,
+				const struct bpf_obj_pin_opts *opts);
+
+struct bpf_obj_get_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+
+	__u32 file_flags;
+	int path_fd;
+
+	size_t :0;
+};
+#define bpf_obj_get_opts__last_field path_fd
+
+LIBBPF_API int bpf_obj_get(const char *pathname);
+LIBBPF_API int bpf_obj_get_opts(const char *pathname,
+				const struct bpf_obj_get_opts *opts);
+
+LIBBPF_API int bpf_prog_attach(int prog_fd, int attachable_fd,
+			       enum bpf_attach_type type, unsigned int flags);
+LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
+LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd,
+				enum bpf_attach_type type);
+
+struct bpf_prog_attach_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 flags;
+	union {
+		int replace_prog_fd;
+		int replace_fd;
+	};
+	int relative_fd;
+	__u32 relative_id;
+	__u64 expected_revision;
+	size_t :0;
+};
+#define bpf_prog_attach_opts__last_field expected_revision
+
+struct bpf_prog_detach_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 flags;
+	int relative_fd;
+	__u32 relative_id;
+	__u64 expected_revision;
+	size_t :0;
+};
+#define bpf_prog_detach_opts__last_field expected_revision
+
+/**
+ * @brief **bpf_prog_attach_opts()** attaches the BPF program corresponding to
+ * *prog_fd* to a *target* which can represent a file descriptor or netdevice
+ * ifindex.
+ *
+ * @param prog_fd BPF program file descriptor
+ * @param target attach location file descriptor or ifindex
+ * @param type attach type for the BPF program
+ * @param opts options for configuring the attachment
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_prog_attach_opts(int prog_fd, int target,
+				    enum bpf_attach_type type,
+				    const struct bpf_prog_attach_opts *opts);
+
+/**
+ * @brief **bpf_prog_detach_opts()** detaches the BPF program corresponding to
+ * *prog_fd* from a *target* which can represent a file descriptor or netdevice
+ * ifindex.
+ *
+ * @param prog_fd BPF program file descriptor
+ * @param target detach location file descriptor or ifindex
+ * @param type detach type for the BPF program
+ * @param opts options for configuring the detachment
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_prog_detach_opts(int prog_fd, int target,
+				    enum bpf_attach_type type,
+				    const struct bpf_prog_detach_opts *opts);
+
+union bpf_iter_link_info; /* defined in up-to-date linux/bpf.h */
+struct bpf_link_create_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 flags;
+	union bpf_iter_link_info *iter_info;
+	__u32 iter_info_len;
+	__u32 target_btf_id;
+	union {
+		struct {
+			__u64 bpf_cookie;
+		} perf_event;
+		struct {
+			__u32 flags;
+			__u32 cnt;
+			const char **syms;
+			const unsigned long *addrs;
+			const __u64 *cookies;
+		} kprobe_multi;
+		struct {
+			__u32 flags;
+			__u32 cnt;
+			const char *path;
+			const unsigned long *offsets;
+			const unsigned long *ref_ctr_offsets;
+			const __u64 *cookies;
+			__u32 pid;
+			__u32 path_fd;
+		} uprobe_multi;
+		struct {
+			__u64 cookie;
+		} tracing;
+		struct {
+			__u32 pf;
+			__u32 hooknum;
+			__s32 priority;
+			__u32 flags;
+		} netfilter;
+		struct {
+			__u32 relative_fd;
+			__u32 relative_id;
+			__u64 expected_revision;
+		} tcx;
+		struct {
+			__u32 relative_fd;
+			__u32 relative_id;
+			__u64 expected_revision;
+		} netkit;
+		struct {
+			__u32 relative_fd;
+			__u32 relative_id;
+			__u64 expected_revision;
+		} cgroup;
+		struct {
+			const __u32 *ids;
+			const __u64 *cookies;
+			__u32 cnt;
+		} tracing_multi;
+	};
+	size_t :0;
+};
+#define bpf_link_create_opts__last_field uprobe_multi.path_fd
+
+LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
+			       enum bpf_attach_type attach_type,
+			       const struct bpf_link_create_opts *opts);
+
+LIBBPF_API int bpf_link_detach(int link_fd);
+
+struct bpf_link_update_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 flags;	   /* extra flags */
+	__u32 old_prog_fd; /* expected old program FD */
+	__u32 old_map_fd;  /* expected old map FD */
+};
+#define bpf_link_update_opts__last_field old_map_fd
+
+LIBBPF_API int bpf_link_update(int link_fd, int new_prog_fd,
+			       const struct bpf_link_update_opts *opts);
+
+LIBBPF_API int bpf_iter_create(int link_fd);
+
+struct bpf_prog_test_run_attr {
+	int prog_fd;
+	int repeat;
+	const void *data_in;
+	__u32 data_size_in;
+	void *data_out;      /* optional */
+	__u32 data_size_out; /* in: max length of data_out
+			      * out: length of data_out */
+	__u32 retval;        /* out: return code of the BPF program */
+	__u32 duration;      /* out: average per repetition in ns */
+	const void *ctx_in; /* optional */
+	__u32 ctx_size_in;
+	void *ctx_out;      /* optional */
+	__u32 ctx_size_out; /* in: max length of ctx_out
+			     * out: length of cxt_out */
+};
+
+LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id);
+LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id);
+LIBBPF_API int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id);
+LIBBPF_API int bpf_link_get_next_id(__u32 start_id, __u32 *next_id);
+
+struct bpf_get_fd_by_id_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 open_flags; /* permissions requested for the operation on fd */
+	__u32 token_fd;
+	size_t :0;
+};
+#define bpf_get_fd_by_id_opts__last_field token_fd
+
+LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_prog_get_fd_by_id_opts(__u32 id,
+				const struct bpf_get_fd_by_id_opts *opts);
+LIBBPF_API int bpf_map_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_map_get_fd_by_id_opts(__u32 id,
+				const struct bpf_get_fd_by_id_opts *opts);
+LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_btf_get_fd_by_id_opts(__u32 id,
+				const struct bpf_get_fd_by_id_opts *opts);
+LIBBPF_API int bpf_link_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_link_get_fd_by_id_opts(__u32 id,
+				const struct bpf_get_fd_by_id_opts *opts);
+LIBBPF_API int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len);
+
+/**
+ * @brief **bpf_prog_get_info_by_fd()** obtains information about the BPF
+ * program corresponding to *prog_fd*.
+ *
+ * Populates up to *info_len* bytes of *info* and updates *info_len* with the
+ * actual number of bytes written to *info*. Note that *info* should be
+ * zero-initialized or initialized as expected by the requested *info*
+ * type. Failing to (zero-)initialize *info* under certain circumstances can
+ * result in this helper returning an error.
+ *
+ * @param prog_fd BPF program file descriptor
+ * @param info pointer to **struct bpf_prog_info** that will be populated with
+ * BPF program information
+ * @param info_len pointer to the size of *info*; on success updated with the
+ * number of bytes written to *info*
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_prog_get_info_by_fd(int prog_fd, struct bpf_prog_info *info, __u32 *info_len);
+
+/**
+ * @brief **bpf_map_get_info_by_fd()** obtains information about the BPF
+ * map corresponding to *map_fd*.
+ *
+ * Populates up to *info_len* bytes of *info* and updates *info_len* with the
+ * actual number of bytes written to *info*. Note that *info* should be
+ * zero-initialized or initialized as expected by the requested *info*
+ * type. Failing to (zero-)initialize *info* under certain circumstances can
+ * result in this helper returning an error.
+ *
+ * @param map_fd BPF map file descriptor
+ * @param info pointer to **struct bpf_map_info** that will be populated with
+ * BPF map information
+ * @param info_len pointer to the size of *info*; on success updated with the
+ * number of bytes written to *info*
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_get_info_by_fd(int map_fd, struct bpf_map_info *info, __u32 *info_len);
+
+/**
+ * @brief **bpf_btf_get_info_by_fd()** obtains information about the
+ * BTF object corresponding to *btf_fd*.
+ *
+ * Populates up to *info_len* bytes of *info* and updates *info_len* with the
+ * actual number of bytes written to *info*. Note that *info* should be
+ * zero-initialized or initialized as expected by the requested *info*
+ * type. Failing to (zero-)initialize *info* under certain circumstances can
+ * result in this helper returning an error.
+ *
+ * @param btf_fd BTF object file descriptor
+ * @param info pointer to **struct bpf_btf_info** that will be populated with
+ * BTF object information
+ * @param info_len pointer to the size of *info*; on success updated with the
+ * number of bytes written to *info*
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_btf_get_info_by_fd(int btf_fd, struct bpf_btf_info *info, __u32 *info_len);
+
+/**
+ * @brief **bpf_btf_get_info_by_fd()** obtains information about the BPF
+ * link corresponding to *link_fd*.
+ *
+ * Populates up to *info_len* bytes of *info* and updates *info_len* with the
+ * actual number of bytes written to *info*. Note that *info* should be
+ * zero-initialized or initialized as expected by the requested *info*
+ * type. Failing to (zero-)initialize *info* under certain circumstances can
+ * result in this helper returning an error.
+ *
+ * @param link_fd BPF link file descriptor
+ * @param info pointer to **struct bpf_link_info** that will be populated with
+ * BPF link information
+ * @param info_len pointer to the size of *info*; on success updated with the
+ * number of bytes written to *info*
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_link_get_info_by_fd(int link_fd, struct bpf_link_info *info, __u32 *info_len);
+
+struct bpf_prog_query_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 query_flags;
+	__u32 attach_flags; /* output argument */
+	__u32 *prog_ids;
+	union {
+		/* input+output argument */
+		__u32 prog_cnt;
+		__u32 count;
+	};
+	__u32 *prog_attach_flags;
+	__u32 *link_ids;
+	__u32 *link_attach_flags;
+	__u64 revision;
+	size_t :0;
+};
+#define bpf_prog_query_opts__last_field revision
+
+/**
+ * @brief **bpf_prog_query_opts()** queries the BPF programs and BPF links
+ * which are attached to *target* which can represent a file descriptor or
+ * netdevice ifindex.
+ *
+ * @param target query location file descriptor or ifindex
+ * @param type attach type for the BPF program
+ * @param opts options for configuring the query
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_prog_query_opts(int target, enum bpf_attach_type type,
+				   struct bpf_prog_query_opts *opts);
+LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type,
+			      __u32 query_flags, __u32 *attach_flags,
+			      __u32 *prog_ids, __u32 *prog_cnt);
+
+struct bpf_raw_tp_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	const char *tp_name;
+	__u64 cookie;
+	size_t :0;
+};
+#define bpf_raw_tp_opts__last_field cookie
+
+LIBBPF_API int bpf_raw_tracepoint_open_opts(int prog_fd, struct bpf_raw_tp_opts *opts);
+LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd);
+LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
+				 __u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
+				 __u64 *probe_offset, __u64 *probe_addr);
+
+#ifdef __cplusplus
+/* forward-declaring enums in C++ isn't compatible with pure C enums, so
+ * instead define bpf_enable_stats() as accepting int as an input
+ */
+LIBBPF_API int bpf_enable_stats(int type);
+#else
+enum bpf_stats_type; /* defined in up-to-date linux/bpf.h */
+LIBBPF_API int bpf_enable_stats(enum bpf_stats_type type);
+#endif
+
+struct bpf_prog_bind_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 flags;
+};
+#define bpf_prog_bind_opts__last_field flags
+
+LIBBPF_API int bpf_prog_bind_map(int prog_fd, int map_fd,
+				 const struct bpf_prog_bind_opts *opts);
+
+struct bpf_test_run_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	const void *data_in; /* optional */
+	void *data_out;      /* optional */
+	__u32 data_size_in;
+	__u32 data_size_out; /* in: max length of data_out
+			      * out: length of data_out
+			      */
+	const void *ctx_in; /* optional */
+	void *ctx_out;      /* optional */
+	__u32 ctx_size_in;
+	__u32 ctx_size_out; /* in: max length of ctx_out
+			     * out: length of cxt_out
+			     */
+	__u32 retval;        /* out: return code of the BPF program */
+	int repeat;
+	__u32 duration;      /* out: average per repetition in ns */
+	__u32 flags;
+	__u32 cpu;
+	__u32 batch_size;
+};
+#define bpf_test_run_opts__last_field batch_size
+
+LIBBPF_API int bpf_prog_test_run_opts(int prog_fd,
+				      struct bpf_test_run_opts *opts);
+
+struct bpf_token_create_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u32 flags;
+	size_t :0;
+};
+#define bpf_token_create_opts__last_field flags
+
+/**
+ * @brief **bpf_token_create()** creates a new instance of BPF token derived
+ * from specified BPF FS mount point.
+ *
+ * BPF token created with this API can be passed to bpf() syscall for
+ * commands like BPF_PROG_LOAD, BPF_MAP_CREATE, etc.
+ *
+ * @param bpffs_fd FD for BPF FS instance from which to derive a BPF token
+ * instance.
+ * @param opts optional BPF token creation options, can be NULL
+ *
+ * @return BPF token FD > 0, on success; negative error code, otherwise (errno
+ * is also set to the error code)
+ */
+LIBBPF_API int bpf_token_create(int bpffs_fd,
+				struct bpf_token_create_opts *opts);
+
+struct bpf_prog_stream_read_opts {
+	size_t sz;
+	size_t :0;
+};
+#define bpf_prog_stream_read_opts__last_field sz
+/**
+ * @brief **bpf_prog_stream_read** reads data from the BPF stream of a given BPF
+ * program.
+ *
+ * @param prog_fd FD for the BPF program whose BPF stream is to be read.
+ * @param stream_id ID of the BPF stream to be read.
+ * @param buf Buffer to read data into from the BPF stream.
+ * @param buf_len Maximum number of bytes to read from the BPF stream.
+ * @param opts optional options, can be NULL
+ *
+ * @return The number of bytes read, on success; negative error code, otherwise
+ * (errno is also set to the error code)
+ */
+LIBBPF_API int bpf_prog_stream_read(int prog_fd, __u32 stream_id, void *buf, __u32 buf_len,
+				    struct bpf_prog_stream_read_opts *opts);
+
+struct bpf_prog_assoc_struct_ops_opts {
+	size_t sz;
+	__u32 flags;
+	size_t :0;
+};
+#define bpf_prog_assoc_struct_ops_opts__last_field flags
+
+/**
+ * @brief **bpf_prog_assoc_struct_ops** associates a BPF program with a
+ * struct_ops map.
+ *
+ * @param prog_fd FD for the BPF program
+ * @param map_fd FD for the struct_ops map to be associated with the BPF program
+ * @param opts optional options, can be NULL
+ *
+ * @return 0 on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_prog_assoc_struct_ops(int prog_fd, int map_fd,
+					 struct bpf_prog_assoc_struct_ops_opts *opts);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* __LIBBPF_BPF_H */
diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h
new file mode 100644
index 000000000..b997c68bd
--- /dev/null
+++ b/tools/lib/bpf/bpf_core_read.h
@@ -0,0 +1,567 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __BPF_CORE_READ_H__
+#define __BPF_CORE_READ_H__
+
+#include "bpf_helpers.h"
+
+/*
+ * enum bpf_field_info_kind is passed as a second argument into
+ * __builtin_preserve_field_info() built-in to get a specific aspect of
+ * a field, captured as a first argument. __builtin_preserve_field_info(field,
+ * info_kind) returns __u32 integer and produces BTF field relocation, which
+ * is understood and processed by libbpf during BPF object loading. See
+ * selftests/bpf for examples.
+ */
+enum bpf_field_info_kind {
+	BPF_FIELD_BYTE_OFFSET = 0,	/* field byte offset */
+	BPF_FIELD_BYTE_SIZE = 1,
+	BPF_FIELD_EXISTS = 2,		/* field existence in target kernel */
+	BPF_FIELD_SIGNED = 3,
+	BPF_FIELD_LSHIFT_U64 = 4,
+	BPF_FIELD_RSHIFT_U64 = 5,
+};
+
+/* second argument to __builtin_btf_type_id() built-in */
+enum bpf_type_id_kind {
+	BPF_TYPE_ID_LOCAL = 0,		/* BTF type ID in local program */
+	BPF_TYPE_ID_TARGET = 1,		/* BTF type ID in target kernel */
+};
+
+/* second argument to __builtin_preserve_type_info() built-in */
+enum bpf_type_info_kind {
+	BPF_TYPE_EXISTS = 0,		/* type existence in target kernel */
+	BPF_TYPE_SIZE = 1,		/* type size in target kernel */
+	BPF_TYPE_MATCHES = 2,		/* type match in target kernel */
+};
+
+/* second argument to __builtin_preserve_enum_value() built-in */
+enum bpf_enum_value_kind {
+	BPF_ENUMVAL_EXISTS = 0,		/* enum value existence in kernel */
+	BPF_ENUMVAL_VALUE = 1,		/* enum value value relocation */
+};
+
+#define __CORE_RELO(src, field, info)					      \
+	__builtin_preserve_field_info((src)->field, BPF_FIELD_##info)
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define __CORE_BITFIELD_PROBE_READ(dst, src, fld)			      \
+	bpf_probe_read_kernel(						      \
+			(void *)dst,					      \
+			__CORE_RELO(src, fld, BYTE_SIZE),		      \
+			(const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET))
+#else
+/* semantics of LSHIFT_64 assumes loading values into low-ordered bytes, so
+ * for big-endian we need to adjust destination pointer accordingly, based on
+ * field byte size
+ */
+#define __CORE_BITFIELD_PROBE_READ(dst, src, fld)			      \
+	bpf_probe_read_kernel(						      \
+			(void *)dst + (8 - __CORE_RELO(src, fld, BYTE_SIZE)), \
+			__CORE_RELO(src, fld, BYTE_SIZE),		      \
+			(const void *)src + __CORE_RELO(src, fld, BYTE_OFFSET))
+#endif
+
+/*
+ * Extract bitfield, identified by s->field, and return its value as u64.
+ * All this is done in relocatable manner, so bitfield changes such as
+ * signedness, bit size, offset changes, this will be handled automatically.
+ * This version of macro is using bpf_probe_read_kernel() to read underlying
+ * integer storage. Macro functions as an expression and its return type is
+ * bpf_probe_read_kernel()'s return value: 0, on success, <0 on error.
+ */
+#define BPF_CORE_READ_BITFIELD_PROBED(s, field) ({			      \
+	unsigned long long val = 0;					      \
+									      \
+	__CORE_BITFIELD_PROBE_READ(&val, s, field);			      \
+	val <<= __CORE_RELO(s, field, LSHIFT_U64);			      \
+	if (__CORE_RELO(s, field, SIGNED))				      \
+		val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64);  \
+	else								      \
+		val = val >> __CORE_RELO(s, field, RSHIFT_U64);		      \
+	val;								      \
+})
+
+/*
+ * Extract bitfield, identified by s->field, and return its value as u64.
+ * This version of macro is using direct memory reads and should be used from
+ * BPF program types that support such functionality (e.g., typed raw
+ * tracepoints).
+ */
+#define BPF_CORE_READ_BITFIELD(s, field) ({				      \
+	const void *p = (const void *)s + __CORE_RELO(s, field, BYTE_OFFSET); \
+	unsigned long long val;						      \
+									      \
+	/* This is a so-called barrier_var() operation that makes specified   \
+	 * variable "a black box" for optimizing compiler.		      \
+	 * It forces compiler to perform BYTE_OFFSET relocation on p and use  \
+	 * its calculated value in the switch below, instead of applying      \
+	 * the same relocation 4 times for each individual memory load.       \
+	 */								      \
+	asm volatile("" : "=r"(p) : "0"(p));				      \
+									      \
+	switch (__CORE_RELO(s, field, BYTE_SIZE)) {			      \
+	case 1: val = *(const unsigned char *)p; break;			      \
+	case 2: val = *(const unsigned short *)p; break;		      \
+	case 4: val = *(const unsigned int *)p; break;			      \
+	case 8: val = *(const unsigned long long *)p; break;		      \
+	default: val = 0; break;					      \
+	}								      \
+	val <<= __CORE_RELO(s, field, LSHIFT_U64);			      \
+	if (__CORE_RELO(s, field, SIGNED))				      \
+		val = ((long long)val) >> __CORE_RELO(s, field, RSHIFT_U64);  \
+	else								      \
+		val = val >> __CORE_RELO(s, field, RSHIFT_U64);		      \
+	val;								      \
+})
+
+/*
+ * Write to a bitfield, identified by s->field.
+ * This is the inverse of BPF_CORE_WRITE_BITFIELD().
+ */
+#define BPF_CORE_WRITE_BITFIELD(s, field, new_val) ({			\
+	void *p = (void *)s + __CORE_RELO(s, field, BYTE_OFFSET);	\
+	unsigned int byte_size = __CORE_RELO(s, field, BYTE_SIZE);	\
+	unsigned int lshift = __CORE_RELO(s, field, LSHIFT_U64);	\
+	unsigned int rshift = __CORE_RELO(s, field, RSHIFT_U64);	\
+	unsigned long long mask, val, nval = new_val;			\
+	unsigned int rpad = rshift - lshift;				\
+									\
+	asm volatile("" : "+r"(p));					\
+									\
+	switch (byte_size) {						\
+	case 1: val = *(unsigned char *)p; break;			\
+	case 2: val = *(unsigned short *)p; break;			\
+	case 4: val = *(unsigned int *)p; break;			\
+	case 8: val = *(unsigned long long *)p; break;			\
+	}								\
+									\
+	mask = (~0ULL << rshift) >> lshift;				\
+	val = (val & ~mask) | ((nval << rpad) & mask);			\
+									\
+	switch (byte_size) {						\
+	case 1: *(unsigned char *)p      = val; break;			\
+	case 2: *(unsigned short *)p     = val; break;			\
+	case 4: *(unsigned int *)p       = val; break;			\
+	case 8: *(unsigned long long *)p = val; break;			\
+	}								\
+})
+
+/* Differentiator between compilers builtin implementations. This is a
+ * requirement due to the compiler parsing differences where GCC optimizes
+ * early in parsing those constructs of type pointers to the builtin specific
+ * type, resulting in not being possible to collect the required type
+ * information in the builtin expansion.
+ */
+#ifdef __clang__
+#define ___bpf_typeof(type) ((typeof(type) *) 0)
+#else
+#define ___bpf_typeof1(type, NR) ({					    \
+	extern typeof(type) *___concat(bpf_type_tmp_, NR);		    \
+	___concat(bpf_type_tmp_, NR);					    \
+})
+#define ___bpf_typeof(type) ___bpf_typeof1(type, __COUNTER__)
+#endif
+
+#ifdef __clang__
+#define ___bpf_field_ref1(field)	(field)
+#define ___bpf_field_ref2(type, field)	(___bpf_typeof(type)->field)
+#else
+#define ___bpf_field_ref1(field)	(&(field))
+#define ___bpf_field_ref2(type, field)	(&(___bpf_typeof(type)->field))
+#endif
+#define ___bpf_field_ref(args...)					    \
+	___bpf_apply(___bpf_field_ref, ___bpf_narg(args))(args)
+
+/*
+ * Convenience macro to check that field actually exists in target kernel's.
+ * Returns:
+ *    1, if matching field is present in target kernel;
+ *    0, if no matching field found.
+ *
+ * Supports two forms:
+ *   - field reference through variable access:
+ *     bpf_core_field_exists(p->my_field);
+ *   - field reference through type and field names:
+ *     bpf_core_field_exists(struct my_type, my_field).
+ */
+#define bpf_core_field_exists(field...)					    \
+	__builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_EXISTS)
+
+/*
+ * Convenience macro to get the byte size of a field. Works for integers,
+ * struct/unions, pointers, arrays, and enums.
+ *
+ * Supports two forms:
+ *   - field reference through variable access:
+ *     bpf_core_field_size(p->my_field);
+ *   - field reference through type and field names:
+ *     bpf_core_field_size(struct my_type, my_field).
+ */
+#define bpf_core_field_size(field...)					    \
+	__builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_BYTE_SIZE)
+
+/*
+ * Convenience macro to get field's byte offset.
+ *
+ * Supports two forms:
+ *   - field reference through variable access:
+ *     bpf_core_field_offset(p->my_field);
+ *   - field reference through type and field names:
+ *     bpf_core_field_offset(struct my_type, my_field).
+ */
+#define bpf_core_field_offset(field...)					    \
+	__builtin_preserve_field_info(___bpf_field_ref(field), BPF_FIELD_BYTE_OFFSET)
+
+/*
+ * Convenience macro to get BTF type ID of a specified type, using a local BTF
+ * information. Return 32-bit unsigned integer with type ID from program's own
+ * BTF. Always succeeds.
+ */
+#define bpf_core_type_id_local(type)					    \
+	__builtin_btf_type_id(*___bpf_typeof(type), BPF_TYPE_ID_LOCAL)
+
+/*
+ * Convenience macro to get BTF type ID of a target kernel's type that matches
+ * specified local type.
+ * Returns:
+ *    - valid 32-bit unsigned type ID in kernel BTF;
+ *    - 0, if no matching type was found in a target kernel BTF.
+ */
+#define bpf_core_type_id_kernel(type)					    \
+	__builtin_btf_type_id(*___bpf_typeof(type), BPF_TYPE_ID_TARGET)
+
+/*
+ * Convenience macro to check that provided named type
+ * (struct/union/enum/typedef) exists in a target kernel.
+ * Returns:
+ *    1, if such type is present in target kernel's BTF;
+ *    0, if no matching type is found.
+ */
+#define bpf_core_type_exists(type)					    \
+	__builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_EXISTS)
+
+/*
+ * Convenience macro to check that provided named type
+ * (struct/union/enum/typedef) "matches" that in a target kernel.
+ * Returns:
+ *    1, if the type matches in the target kernel's BTF;
+ *    0, if the type does not match any in the target kernel
+ */
+#define bpf_core_type_matches(type)					    \
+	__builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_MATCHES)
+
+/*
+ * Convenience macro to get the byte size of a provided named type
+ * (struct/union/enum/typedef) in a target kernel.
+ * Returns:
+ *    >= 0 size (in bytes), if type is present in target kernel's BTF;
+ *    0, if no matching type is found.
+ */
+#define bpf_core_type_size(type)					    \
+	__builtin_preserve_type_info(*___bpf_typeof(type), BPF_TYPE_SIZE)
+
+/*
+ * Convenience macro to check that provided enumerator value is defined in
+ * a target kernel.
+ * Returns:
+ *    1, if specified enum type and its enumerator value are present in target
+ *    kernel's BTF;
+ *    0, if no matching enum and/or enum value within that enum is found.
+ */
+#ifdef __clang__
+#define bpf_core_enum_value_exists(enum_type, enum_value)		    \
+	__builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS)
+#else
+#define bpf_core_enum_value_exists(enum_type, enum_value)		    \
+	__builtin_preserve_enum_value(___bpf_typeof(enum_type), enum_value, BPF_ENUMVAL_EXISTS)
+#endif
+
+/*
+ * Convenience macro to get the integer value of an enumerator value in
+ * a target kernel.
+ * Returns:
+ *    64-bit value, if specified enum type and its enumerator value are
+ *    present in target kernel's BTF;
+ *    0, if no matching enum and/or enum value within that enum is found.
+ */
+#ifdef __clang__
+#define bpf_core_enum_value(enum_type, enum_value)			    \
+	__builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_VALUE)
+#else
+#define bpf_core_enum_value(enum_type, enum_value)			    \
+	__builtin_preserve_enum_value(___bpf_typeof(enum_type), enum_value, BPF_ENUMVAL_VALUE)
+#endif
+
+/*
+ * bpf_core_read() abstracts away bpf_probe_read_kernel() call and captures
+ * offset relocation for source address using __builtin_preserve_access_index()
+ * built-in, provided by Clang.
+ *
+ * __builtin_preserve_access_index() takes as an argument an expression of
+ * taking an address of a field within struct/union. It makes compiler emit
+ * a relocation, which records BTF type ID describing root struct/union and an
+ * accessor string which describes exact embedded field that was used to take
+ * an address. See detailed description of this relocation format and
+ * semantics in comments to struct bpf_core_relo in include/uapi/linux/bpf.h.
+ *
+ * This relocation allows libbpf to adjust BPF instruction to use correct
+ * actual field offset, based on target kernel BTF type that matches original
+ * (local) BTF, used to record relocation.
+ */
+#define bpf_core_read(dst, sz, src)					    \
+	bpf_probe_read_kernel(dst, sz, (const void *)__builtin_preserve_access_index(src))
+
+/* NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. */
+#define bpf_core_read_user(dst, sz, src)				    \
+	bpf_probe_read_user(dst, sz, (const void *)__builtin_preserve_access_index(src))
+/*
+ * bpf_core_read_str() is a thin wrapper around bpf_probe_read_str()
+ * additionally emitting BPF CO-RE field relocation for specified source
+ * argument.
+ */
+#define bpf_core_read_str(dst, sz, src)					    \
+	bpf_probe_read_kernel_str(dst, sz, (const void *)__builtin_preserve_access_index(src))
+
+/* NOTE: see comments for BPF_CORE_READ_USER() about the proper types use. */
+#define bpf_core_read_user_str(dst, sz, src)				    \
+	bpf_probe_read_user_str(dst, sz, (const void *)__builtin_preserve_access_index(src))
+
+extern void *bpf_rdonly_cast(const void *obj, __u32 btf_id) __ksym __weak;
+
+/*
+ * Cast provided pointer *ptr* into a pointer to a specified *type* in such
+ * a way that BPF verifier will become aware of associated kernel-side BTF
+ * type. This allows to access members of kernel types directly without the
+ * need to use BPF_CORE_READ() macros.
+ */
+#define bpf_core_cast(ptr, type)					    \
+	((typeof(type) *)bpf_rdonly_cast((ptr), bpf_core_type_id_kernel(type)))
+
+#define ___concat(a, b) a ## b
+#define ___apply(fn, n) ___concat(fn, n)
+#define ___nth(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, __11, N, ...) N
+
+/*
+ * return number of provided arguments; used for switch-based variadic macro
+ * definitions (see ___last, ___arrow, etc below)
+ */
+#define ___narg(...) ___nth(_, ##__VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+/*
+ * return 0 if no arguments are passed, N - otherwise; used for
+ * recursively-defined macros to specify termination (0) case, and generic
+ * (N) case (e.g., ___read_ptrs, ___core_read)
+ */
+#define ___empty(...) ___nth(_, ##__VA_ARGS__, N, N, N, N, N, N, N, N, N, N, 0)
+
+#define ___last1(x) x
+#define ___last2(a, x) x
+#define ___last3(a, b, x) x
+#define ___last4(a, b, c, x) x
+#define ___last5(a, b, c, d, x) x
+#define ___last6(a, b, c, d, e, x) x
+#define ___last7(a, b, c, d, e, f, x) x
+#define ___last8(a, b, c, d, e, f, g, x) x
+#define ___last9(a, b, c, d, e, f, g, h, x) x
+#define ___last10(a, b, c, d, e, f, g, h, i, x) x
+#define ___last(...) ___apply(___last, ___narg(__VA_ARGS__))(__VA_ARGS__)
+
+#define ___nolast2(a, _) a
+#define ___nolast3(a, b, _) a, b
+#define ___nolast4(a, b, c, _) a, b, c
+#define ___nolast5(a, b, c, d, _) a, b, c, d
+#define ___nolast6(a, b, c, d, e, _) a, b, c, d, e
+#define ___nolast7(a, b, c, d, e, f, _) a, b, c, d, e, f
+#define ___nolast8(a, b, c, d, e, f, g, _) a, b, c, d, e, f, g
+#define ___nolast9(a, b, c, d, e, f, g, h, _) a, b, c, d, e, f, g, h
+#define ___nolast10(a, b, c, d, e, f, g, h, i, _) a, b, c, d, e, f, g, h, i
+#define ___nolast(...) ___apply(___nolast, ___narg(__VA_ARGS__))(__VA_ARGS__)
+
+#define ___arrow1(a) a
+#define ___arrow2(a, b) a->b
+#define ___arrow3(a, b, c) a->b->c
+#define ___arrow4(a, b, c, d) a->b->c->d
+#define ___arrow5(a, b, c, d, e) a->b->c->d->e
+#define ___arrow6(a, b, c, d, e, f) a->b->c->d->e->f
+#define ___arrow7(a, b, c, d, e, f, g) a->b->c->d->e->f->g
+#define ___arrow8(a, b, c, d, e, f, g, h) a->b->c->d->e->f->g->h
+#define ___arrow9(a, b, c, d, e, f, g, h, i) a->b->c->d->e->f->g->h->i
+#define ___arrow10(a, b, c, d, e, f, g, h, i, j) a->b->c->d->e->f->g->h->i->j
+#define ___arrow(...) ___apply(___arrow, ___narg(__VA_ARGS__))(__VA_ARGS__)
+
+#if defined(__clang__) && (__clang_major__ >= 19)
+#define ___type(...) __typeof_unqual__(___arrow(__VA_ARGS__))
+#elif defined(__GNUC__) && (__GNUC__ >= 14)
+#define ___type(...) __typeof_unqual__(___arrow(__VA_ARGS__))
+#else
+#define ___type(...) typeof(___arrow(__VA_ARGS__))
+#endif
+
+#define ___read(read_fn, dst, src_type, src, accessor)			    \
+	read_fn((void *)(dst), sizeof(*(dst)), &((src_type)(src))->accessor)
+
+/* "recursively" read a sequence of inner pointers using local __t var */
+#define ___rd_first(fn, src, a) ___read(fn, &__t, ___type(src), src, a);
+#define ___rd_last(fn, ...)						    \
+	___read(fn, &__t, ___type(___nolast(__VA_ARGS__)), __t, ___last(__VA_ARGS__));
+#define ___rd_p1(fn, ...) const void *__t; ___rd_first(fn, __VA_ARGS__)
+#define ___rd_p2(fn, ...) ___rd_p1(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p3(fn, ...) ___rd_p2(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p4(fn, ...) ___rd_p3(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p5(fn, ...) ___rd_p4(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p6(fn, ...) ___rd_p5(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p7(fn, ...) ___rd_p6(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p8(fn, ...) ___rd_p7(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___rd_p9(fn, ...) ___rd_p8(fn, ___nolast(__VA_ARGS__)) ___rd_last(fn, __VA_ARGS__)
+#define ___read_ptrs(fn, src, ...)					    \
+	___apply(___rd_p, ___narg(__VA_ARGS__))(fn, src, __VA_ARGS__)
+
+#define ___core_read0(fn, fn_ptr, dst, src, a)				    \
+	___read(fn, dst, ___type(src), src, a);
+#define ___core_readN(fn, fn_ptr, dst, src, ...)			    \
+	___read_ptrs(fn_ptr, src, ___nolast(__VA_ARGS__))		    \
+	___read(fn, dst, ___type(src, ___nolast(__VA_ARGS__)), __t,	    \
+		___last(__VA_ARGS__));
+#define ___core_read(fn, fn_ptr, dst, src, a, ...)			    \
+	___apply(___core_read, ___empty(__VA_ARGS__))(fn, fn_ptr, dst,	    \
+						      src, a, ##__VA_ARGS__)
+
+/*
+ * BPF_CORE_READ_INTO() is a more performance-conscious variant of
+ * BPF_CORE_READ(), in which final field is read into user-provided storage.
+ * See BPF_CORE_READ() below for more details on general usage.
+ */
+#define BPF_CORE_READ_INTO(dst, src, a, ...) ({				    \
+	___core_read(bpf_core_read, bpf_core_read,			    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/*
+ * Variant of BPF_CORE_READ_INTO() for reading from user-space memory.
+ *
+ * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use.
+ */
+#define BPF_CORE_READ_USER_INTO(dst, src, a, ...) ({			    \
+	___core_read(bpf_core_read_user, bpf_core_read_user,		    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/* Non-CO-RE variant of BPF_CORE_READ_INTO() */
+#define BPF_PROBE_READ_INTO(dst, src, a, ...) ({			    \
+	___core_read(bpf_probe_read_kernel, bpf_probe_read_kernel,	    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/* Non-CO-RE variant of BPF_CORE_READ_USER_INTO().
+ *
+ * As no CO-RE relocations are emitted, source types can be arbitrary and are
+ * not restricted to kernel types only.
+ */
+#define BPF_PROBE_READ_USER_INTO(dst, src, a, ...) ({			    \
+	___core_read(bpf_probe_read_user, bpf_probe_read_user,		    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/*
+ * BPF_CORE_READ_STR_INTO() does same "pointer chasing" as
+ * BPF_CORE_READ() for intermediate pointers, but then executes (and returns
+ * corresponding error code) bpf_core_read_str() for final string read.
+ */
+#define BPF_CORE_READ_STR_INTO(dst, src, a, ...) ({			    \
+	___core_read(bpf_core_read_str, bpf_core_read,			    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/*
+ * Variant of BPF_CORE_READ_STR_INTO() for reading from user-space memory.
+ *
+ * NOTE: see comments for BPF_CORE_READ_USER() about the proper types use.
+ */
+#define BPF_CORE_READ_USER_STR_INTO(dst, src, a, ...) ({		    \
+	___core_read(bpf_core_read_user_str, bpf_core_read_user,	    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/* Non-CO-RE variant of BPF_CORE_READ_STR_INTO() */
+#define BPF_PROBE_READ_STR_INTO(dst, src, a, ...) ({			    \
+	___core_read(bpf_probe_read_kernel_str, bpf_probe_read_kernel,	    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/*
+ * Non-CO-RE variant of BPF_CORE_READ_USER_STR_INTO().
+ *
+ * As no CO-RE relocations are emitted, source types can be arbitrary and are
+ * not restricted to kernel types only.
+ */
+#define BPF_PROBE_READ_USER_STR_INTO(dst, src, a, ...) ({		    \
+	___core_read(bpf_probe_read_user_str, bpf_probe_read_user,	    \
+		     dst, (src), a, ##__VA_ARGS__)			    \
+})
+
+/*
+ * BPF_CORE_READ() is used to simplify BPF CO-RE relocatable read, especially
+ * when there are few pointer chasing steps.
+ * E.g., what in non-BPF world (or in BPF w/ BCC) would be something like:
+ *	int x = s->a.b.c->d.e->f->g;
+ * can be succinctly achieved using BPF_CORE_READ as:
+ *	int x = BPF_CORE_READ(s, a.b.c, d.e, f, g);
+ *
+ * BPF_CORE_READ will decompose above statement into 4 bpf_core_read (BPF
+ * CO-RE relocatable bpf_probe_read_kernel() wrapper) calls, logically
+ * equivalent to:
+ * 1. const void *__t = s->a.b.c;
+ * 2. __t = __t->d.e;
+ * 3. __t = __t->f;
+ * 4. return __t->g;
+ *
+ * Equivalence is logical, because there is a heavy type casting/preservation
+ * involved, as well as all the reads are happening through
+ * bpf_probe_read_kernel() calls using __builtin_preserve_access_index() to
+ * emit CO-RE relocations.
+ *
+ * N.B. Only up to 9 "field accessors" are supported, which should be more
+ * than enough for any practical purpose.
+ */
+#define BPF_CORE_READ(src, a, ...) ({					    \
+	___type((src), a, ##__VA_ARGS__) __r;				    \
+	BPF_CORE_READ_INTO(&__r, (src), a, ##__VA_ARGS__);		    \
+	__r;								    \
+})
+
+/*
+ * Variant of BPF_CORE_READ() for reading from user-space memory.
+ *
+ * NOTE: all the source types involved are still *kernel types* and need to
+ * exist in kernel (or kernel module) BTF, otherwise CO-RE relocation will
+ * fail. Custom user types are not relocatable with CO-RE.
+ * The typical situation in which BPF_CORE_READ_USER() might be used is to
+ * read kernel UAPI types from the user-space memory passed in as a syscall
+ * input argument.
+ */
+#define BPF_CORE_READ_USER(src, a, ...) ({				    \
+	___type((src), a, ##__VA_ARGS__) __r;				    \
+	BPF_CORE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__);		    \
+	__r;								    \
+})
+
+/* Non-CO-RE variant of BPF_CORE_READ() */
+#define BPF_PROBE_READ(src, a, ...) ({					    \
+	___type((src), a, ##__VA_ARGS__) __r;				    \
+	BPF_PROBE_READ_INTO(&__r, (src), a, ##__VA_ARGS__);		    \
+	__r;								    \
+})
+
+/*
+ * Non-CO-RE variant of BPF_CORE_READ_USER().
+ *
+ * As no CO-RE relocations are emitted, source types can be arbitrary and are
+ * not restricted to kernel types only.
+ */
+#define BPF_PROBE_READ_USER(src, a, ...) ({				    \
+	___type((src), a, ##__VA_ARGS__) __r;				    \
+	BPF_PROBE_READ_USER_INTO(&__r, (src), a, ##__VA_ARGS__);	    \
+	__r;								    \
+})
+
+#endif
+
diff --git a/tools/lib/bpf/bpf_endian.h b/tools/lib/bpf/bpf_endian.h
new file mode 100644
index 000000000..ec9db4fec
--- /dev/null
+++ b/tools/lib/bpf/bpf_endian.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __BPF_ENDIAN__
+#define __BPF_ENDIAN__
+
+/*
+ * Isolate byte #n and put it into byte #m, for __u##b type.
+ * E.g., moving byte #6 (nnnnnnnn) into byte #1 (mmmmmmmm) for __u64:
+ * 1) xxxxxxxx nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx
+ * 2) nnnnnnnn xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx mmmmmmmm xxxxxxxx 00000000
+ * 3) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn
+ * 4) 00000000 00000000 00000000 00000000 00000000 00000000 nnnnnnnn 00000000
+ */
+#define ___bpf_mvb(x, b, n, m) ((__u##b)(x) << (b-(n+1)*8) >> (b-8) << (m*8))
+
+#define ___bpf_swab16(x) ((__u16)(			\
+			  ___bpf_mvb(x, 16, 0, 1) |	\
+			  ___bpf_mvb(x, 16, 1, 0)))
+
+#define ___bpf_swab32(x) ((__u32)(			\
+			  ___bpf_mvb(x, 32, 0, 3) |	\
+			  ___bpf_mvb(x, 32, 1, 2) |	\
+			  ___bpf_mvb(x, 32, 2, 1) |	\
+			  ___bpf_mvb(x, 32, 3, 0)))
+
+#define ___bpf_swab64(x) ((__u64)(			\
+			  ___bpf_mvb(x, 64, 0, 7) |	\
+			  ___bpf_mvb(x, 64, 1, 6) |	\
+			  ___bpf_mvb(x, 64, 2, 5) |	\
+			  ___bpf_mvb(x, 64, 3, 4) |	\
+			  ___bpf_mvb(x, 64, 4, 3) |	\
+			  ___bpf_mvb(x, 64, 5, 2) |	\
+			  ___bpf_mvb(x, 64, 6, 1) |	\
+			  ___bpf_mvb(x, 64, 7, 0)))
+
+/* LLVM's BPF target selects the endianness of the CPU
+ * it compiles on, or the user specifies (bpfel/bpfeb),
+ * respectively. The used __BYTE_ORDER__ is defined by
+ * the compiler, we cannot rely on __BYTE_ORDER from
+ * libc headers, since it doesn't reflect the actual
+ * requested byte order.
+ *
+ * Note, LLVM's BPF target has different __builtin_bswapX()
+ * semantics. It does map to BPF_ALU | BPF_END | BPF_TO_BE
+ * in bpfel and bpfeb case, which means below, that we map
+ * to cpu_to_be16(). We could use it unconditionally in BPF
+ * case, but better not rely on it, so that this header here
+ * can be used from application and BPF program side, which
+ * use different targets.
+ */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define __bpf_ntohs(x)			__builtin_bswap16(x)
+# define __bpf_htons(x)			__builtin_bswap16(x)
+# define __bpf_constant_ntohs(x)	___bpf_swab16(x)
+# define __bpf_constant_htons(x)	___bpf_swab16(x)
+# define __bpf_ntohl(x)			__builtin_bswap32(x)
+# define __bpf_htonl(x)			__builtin_bswap32(x)
+# define __bpf_constant_ntohl(x)	___bpf_swab32(x)
+# define __bpf_constant_htonl(x)	___bpf_swab32(x)
+# define __bpf_be64_to_cpu(x)		__builtin_bswap64(x)
+# define __bpf_cpu_to_be64(x)		__builtin_bswap64(x)
+# define __bpf_constant_be64_to_cpu(x)	___bpf_swab64(x)
+# define __bpf_constant_cpu_to_be64(x)	___bpf_swab64(x)
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define __bpf_ntohs(x)			(x)
+# define __bpf_htons(x)			(x)
+# define __bpf_constant_ntohs(x)	(x)
+# define __bpf_constant_htons(x)	(x)
+# define __bpf_ntohl(x)			(x)
+# define __bpf_htonl(x)			(x)
+# define __bpf_constant_ntohl(x)	(x)
+# define __bpf_constant_htonl(x)	(x)
+# define __bpf_be64_to_cpu(x)		(x)
+# define __bpf_cpu_to_be64(x)		(x)
+# define __bpf_constant_be64_to_cpu(x)  (x)
+# define __bpf_constant_cpu_to_be64(x)  (x)
+#else
+# error "Fix your compiler's __BYTE_ORDER__?!"
+#endif
+
+#define bpf_htons(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_htons(x) : __bpf_htons(x))
+#define bpf_ntohs(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
+#define bpf_htonl(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_htonl(x) : __bpf_htonl(x))
+#define bpf_ntohl(x)				\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_ntohl(x) : __bpf_ntohl(x))
+#define bpf_cpu_to_be64(x)			\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
+#define bpf_be64_to_cpu(x)			\
+	(__builtin_constant_p(x) ?		\
+	 __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
+
+#endif /* __BPF_ENDIAN__ */
diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h
new file mode 100644
index 000000000..6c5ad6c55
--- /dev/null
+++ b/tools/lib/bpf/bpf_gen_internal.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (c) 2021 Facebook */
+#ifndef __BPF_GEN_INTERNAL_H
+#define __BPF_GEN_INTERNAL_H
+
+#include "bpf.h"
+#include "libbpf_internal.h"
+
+struct ksym_relo_desc {
+	const char *name;
+	int kind;
+	int insn_idx;
+	bool is_weak;
+	bool is_typeless;
+	bool is_ld64;
+};
+
+struct ksym_desc {
+	const char *name;
+	int ref;
+	int kind;
+	union {
+		/* used for kfunc */
+		int off;
+		/* used for typeless ksym */
+		bool typeless;
+	};
+	int insn;
+	bool is_ld64;
+};
+
+struct bpf_gen {
+	struct gen_loader_opts *opts;
+	void *data_start;
+	void *data_cur;
+	void *insn_start;
+	void *insn_cur;
+	bool swapped_endian;
+	ssize_t cleanup_label;
+	__u32 nr_progs;
+	__u32 nr_maps;
+	int log_level;
+	int error;
+	struct ksym_relo_desc *relos;
+	int relo_cnt;
+	struct bpf_core_relo *core_relos;
+	int core_relo_cnt;
+	char attach_target[128];
+	int attach_kind;
+	struct ksym_desc *ksyms;
+	__u32 nr_ksyms;
+	int fd_array;
+	int nr_fd_array;
+};
+
+void bpf_gen__init(struct bpf_gen *gen, int log_level, int nr_progs, int nr_maps);
+int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps);
+void bpf_gen__free(struct bpf_gen *gen);
+void bpf_gen__load_btf(struct bpf_gen *gen, const void *raw_data, __u32 raw_size);
+void bpf_gen__map_create(struct bpf_gen *gen,
+			 enum bpf_map_type map_type, const char *map_name,
+			 __u32 key_size, __u32 value_size, __u32 max_entries,
+			 struct bpf_map_create_opts *map_attr, int map_idx);
+void bpf_gen__prog_load(struct bpf_gen *gen,
+			enum bpf_prog_type prog_type, const char *prog_name,
+			const char *license, struct bpf_insn *insns, size_t insn_cnt,
+			struct bpf_prog_load_opts *load_attr, int prog_idx);
+void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u32 value_size,
+			      __u64 flags);
+void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx);
+void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type);
+void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
+			    bool is_typeless, bool is_ld64, int kind, int insn_idx);
+void bpf_gen__record_relo_core(struct bpf_gen *gen, const struct bpf_core_relo *core_relo);
+void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int key, int inner_map_idx);
+
+#endif
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
new file mode 100644
index 000000000..9d160b5b9
--- /dev/null
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -0,0 +1,446 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __BPF_HELPERS__
+#define __BPF_HELPERS__
+
+/*
+ * Note that bpf programs need to include either
+ * vmlinux.h (auto-generated from BTF) or linux/types.h
+ * in advance since bpf_helper_defs.h uses such types
+ * as __u64.
+ */
+#include "bpf_helper_defs.h"
+
+#define __uint(name, val) int (*name)[val]
+#define __type(name, val) typeof(val) *name
+#define __array(name, val) typeof(val) *name[]
+#define __ulong(name, val) enum { ___bpf_concat(__unique_value, __COUNTER__) = val } name
+
+#ifndef likely
+#define likely(x)      (__builtin_expect(!!(x), 1))
+#endif
+
+#ifndef unlikely
+#define unlikely(x)    (__builtin_expect(!!(x), 0))
+#endif
+
+/*
+ * Helper macro to place programs, maps, license in
+ * different sections in elf_bpf file. Section names
+ * are interpreted by libbpf depending on the context (BPF programs, BPF maps,
+ * extern variables, etc).
+ * To allow use of SEC() with externs (e.g., for extern .maps declarations),
+ * make sure __attribute__((unused)) doesn't trigger compilation warning.
+ */
+#if __GNUC__ && !__clang__
+
+/*
+ * Pragma macros are broken on GCC
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90400
+ */
+#define SEC(name) __attribute__((section(name), used))
+
+#else
+
+#define SEC(name) \
+	_Pragma("GCC diagnostic push")					    \
+	_Pragma("GCC diagnostic ignored \"-Wignored-attributes\"")	    \
+	__attribute__((section(name), used))				    \
+	_Pragma("GCC diagnostic pop")					    \
+
+#endif
+
+/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
+#undef __always_inline
+#define __always_inline inline __attribute__((always_inline))
+
+#ifndef __noinline
+#define __noinline __attribute__((noinline))
+#endif
+#ifndef __weak
+#define __weak __attribute__((weak))
+#endif
+
+/*
+ * Use __hidden attribute to mark a non-static BPF subprogram effectively
+ * static for BPF verifier's verification algorithm purposes, allowing more
+ * extensive and permissive BPF verification process, taking into account
+ * subprogram's caller context.
+ */
+#define __hidden __attribute__((visibility("hidden")))
+
+/* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include
+ * any system-level headers (such as stddef.h, linux/version.h, etc), and
+ * commonly-used macros like NULL and KERNEL_VERSION aren't available through
+ * vmlinux.h. This just adds unnecessary hurdles and forces users to re-define
+ * them on their own. So as a convenience, provide such definitions here.
+ */
+#ifndef NULL
+#define NULL ((void *)0)
+#endif
+
+#ifndef KERNEL_VERSION
+#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))
+#endif
+
+/*
+ * Helper macros to manipulate data structures
+ */
+
+/* offsetof() definition that uses __builtin_offset() might not preserve field
+ * offset CO-RE relocation properly, so force-redefine offsetof() using
+ * old-school approach which works with CO-RE correctly
+ */
+#undef offsetof
+#define offsetof(type, member)	((unsigned long)&((type *)0)->member)
+
+/* redefined container_of() to ensure we use the above offsetof() macro */
+#undef container_of
+#define container_of(ptr, type, member)				\
+	({							\
+		void *__mptr = (void *)(ptr);			\
+		((type *)(__mptr - offsetof(type, member)));	\
+	})
+
+/*
+ * Compiler (optimization) barrier.
+ */
+#ifndef barrier
+#define barrier() asm volatile("" ::: "memory")
+#endif
+
+/* Variable-specific compiler (optimization) barrier. It's a no-op which makes
+ * compiler believe that there is some black box modification of a given
+ * variable and thus prevents compiler from making extra assumption about its
+ * value and potential simplifications and optimizations on this variable.
+ *
+ * E.g., compiler might often delay or even omit 32-bit to 64-bit casting of
+ * a variable, making some code patterns unverifiable. Putting barrier_var()
+ * in place will ensure that cast is performed before the barrier_var()
+ * invocation, because compiler has to pessimistically assume that embedded
+ * asm section might perform some extra operations on that variable.
+ *
+ * This is a variable-specific variant of more global barrier().
+ */
+#ifndef barrier_var
+#define barrier_var(var) asm volatile("" : "+r"(var))
+#endif
+
+/*
+ * Helper macro to throw a compilation error if __bpf_unreachable() gets
+ * built into the resulting code. This works given BPF back end does not
+ * implement __builtin_trap(). This is useful to assert that certain paths
+ * of the program code are never used and hence eliminated by the compiler.
+ *
+ * For example, consider a switch statement that covers known cases used by
+ * the program. __bpf_unreachable() can then reside in the default case. If
+ * the program gets extended such that a case is not covered in the switch
+ * statement, then it will throw a build error due to the default case not
+ * being compiled out.
+ */
+#ifndef __bpf_unreachable
+# define __bpf_unreachable()	__builtin_trap()
+#endif
+
+/*
+ * Helper function to perform a tail call with a constant/immediate map slot.
+ */
+#if (defined(__clang__) && __clang_major__ >= 8) || (!defined(__clang__) && __GNUC__ > 12)
+#if defined(__bpf__)
+static __always_inline void
+bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
+{
+	if (!__builtin_constant_p(slot))
+		__bpf_unreachable();
+
+	/*
+	 * Provide a hard guarantee that LLVM won't optimize setting r2 (map
+	 * pointer) and r3 (constant map index) from _different paths_ ending
+	 * up at the _same_ call insn as otherwise we won't be able to use the
+	 * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel
+	 * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key
+	 * tracking for prog array pokes") for details on verifier tracking.
+	 *
+	 * Note on clobber list: we need to stay in-line with BPF calling
+	 * convention, so even if we don't end up using r0, r4, r5, we need
+	 * to mark them as clobber so that LLVM doesn't end up using them
+	 * before / after the call.
+	 */
+	asm volatile("r1 = %[ctx]\n\t"
+		     "r2 = %[map]\n\t"
+		     "r3 = %[slot]\n\t"
+		     "call 12"
+		     :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot)
+		     : "r0", "r1", "r2", "r3", "r4", "r5");
+}
+#endif
+#endif
+
+enum libbpf_pin_type {
+	LIBBPF_PIN_NONE,
+	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+	LIBBPF_PIN_BY_NAME,
+};
+
+enum libbpf_tristate {
+	TRI_NO = 0,
+	TRI_YES = 1,
+	TRI_MODULE = 2,
+};
+
+#define __kconfig __attribute__((section(".kconfig")))
+#define __ksym __attribute__((section(".ksyms")))
+#define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted")))
+#define __kptr __attribute__((btf_type_tag("kptr")))
+#define __percpu_kptr __attribute__((btf_type_tag("percpu_kptr")))
+#define __uptr __attribute__((btf_type_tag("uptr")))
+
+#if defined (__clang__)
+#define bpf_ksym_exists(sym) ({						\
+	_Static_assert(!__builtin_constant_p(!!sym),			\
+		       #sym " should be marked as __weak");		\
+	!!sym;								\
+})
+#elif __GNUC__ > 8
+#define bpf_ksym_exists(sym) ({						\
+	_Static_assert(__builtin_has_attribute (*sym, __weak__),	\
+		       #sym " should be marked as __weak");		\
+	!!sym;								\
+})
+#else
+#define bpf_ksym_exists(sym) !!sym
+#endif
+
+#define __arg_ctx __attribute__((btf_decl_tag("arg:ctx")))
+#define __arg_nonnull __attribute((btf_decl_tag("arg:nonnull")))
+#define __arg_nullable __attribute((btf_decl_tag("arg:nullable")))
+#define __arg_trusted __attribute((btf_decl_tag("arg:trusted")))
+#define __arg_untrusted __attribute((btf_decl_tag("arg:untrusted")))
+#define __arg_arena __attribute((btf_decl_tag("arg:arena")))
+
+#ifndef ___bpf_concat
+#define ___bpf_concat(a, b) a ## b
+#endif
+#ifndef ___bpf_apply
+#define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
+#endif
+#ifndef ___bpf_nth
+#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
+#endif
+#ifndef ___bpf_narg
+#define ___bpf_narg(...) \
+	___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+#endif
+
+#define ___bpf_fill0(arr, p, x) do {} while (0)
+#define ___bpf_fill1(arr, p, x) arr[p] = x
+#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
+#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
+#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
+#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
+#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
+#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
+#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
+#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
+#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
+#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
+#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
+#define ___bpf_fill(arr, args...) \
+	___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)
+
+/*
+ * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
+ * in a structure.
+ */
+#define BPF_SEQ_PRINTF(seq, fmt, args...)			\
+({								\
+	static const char ___fmt[] = fmt;			\
+	unsigned long long ___param[___bpf_narg(args)];		\
+								\
+	_Pragma("GCC diagnostic push")				\
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
+	___bpf_fill(___param, args);				\
+	_Pragma("GCC diagnostic pop")				\
+								\
+	bpf_seq_printf(seq, ___fmt, sizeof(___fmt),		\
+		       ___param, sizeof(___param));		\
+})
+
+/*
+ * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
+ * an array of u64.
+ */
+#define BPF_SNPRINTF(out, out_size, fmt, args...)		\
+({								\
+	static const char ___fmt[] = fmt;			\
+	unsigned long long ___param[___bpf_narg(args)];		\
+								\
+	_Pragma("GCC diagnostic push")				\
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
+	___bpf_fill(___param, args);				\
+	_Pragma("GCC diagnostic pop")				\
+								\
+	bpf_snprintf(out, out_size, ___fmt,			\
+		     ___param, sizeof(___param));		\
+})
+
+#ifdef BPF_NO_GLOBAL_DATA
+#define BPF_PRINTK_FMT_MOD
+#else
+#define BPF_PRINTK_FMT_MOD static const
+#endif
+
+#define __bpf_printk(fmt, ...)				\
+({							\
+	BPF_PRINTK_FMT_MOD char ____fmt[] = fmt;	\
+	bpf_trace_printk(____fmt, sizeof(____fmt),	\
+			 ##__VA_ARGS__);		\
+})
+
+/*
+ * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments
+ * instead of an array of u64.
+ */
+#define __bpf_vprintk(fmt, args...)				\
+({								\
+	static const char ___fmt[] = fmt;			\
+	unsigned long long ___param[___bpf_narg(args)];		\
+								\
+	_Pragma("GCC diagnostic push")				\
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
+	___bpf_fill(___param, args);				\
+	_Pragma("GCC diagnostic pop")				\
+								\
+	bpf_trace_vprintk(___fmt, sizeof(___fmt),		\
+			  ___param, sizeof(___param));		\
+})
+
+#define bpf_stream_printk(stream_id, fmt, args...)					\
+({											\
+	static const char ___fmt[] = fmt;						\
+	unsigned long long ___param[___bpf_narg(args)];					\
+											\
+	_Pragma("GCC diagnostic push")							\
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")				\
+	___bpf_fill(___param, args);							\
+	_Pragma("GCC diagnostic pop")							\
+											\
+	bpf_stream_vprintk(stream_id, ___fmt, ___param, sizeof(___param));		\
+})
+
+/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
+ * Otherwise use __bpf_vprintk
+ */
+#define ___bpf_pick_printk(...) \
+	___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk,	\
+		   __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk,		\
+		   __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\
+		   __bpf_printk /*1*/, __bpf_printk /*0*/)
+
+/* Helper macro to print out debug messages */
+#define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args)
+
+struct bpf_iter_num;
+
+extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __weak __ksym;
+extern int *bpf_iter_num_next(struct bpf_iter_num *it) __weak __ksym;
+extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __weak __ksym;
+
+#ifndef bpf_for_each
+/* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for
+ * using BPF open-coded iterators without having to write mundane explicit
+ * low-level loop logic. Instead, it provides for()-like generic construct
+ * that can be used pretty naturally. E.g., for some hypothetical cgroup
+ * iterator, you'd write:
+ *
+ * struct cgroup *cg, *parent_cg = <...>;
+ *
+ * bpf_for_each(cgroup, cg, parent_cg, CG_ITER_CHILDREN) {
+ *     bpf_printk("Child cgroup id = %d", cg->cgroup_id);
+ *     if (cg->cgroup_id == 123)
+ *         break;
+ * }
+ *
+ * I.e., it looks almost like high-level for each loop in other languages,
+ * supports continue/break, and is verifiable by BPF verifier.
+ *
+ * For iterating integers, the difference between bpf_for_each(num, i, N, M)
+ * and bpf_for(i, N, M) is in that bpf_for() provides additional proof to
+ * verifier that i is in [N, M) range, and in bpf_for_each() case i is `int
+ * *`, not just `int`. So for integers bpf_for() is more convenient.
+ *
+ * Note: this macro relies on C99 feature of allowing to declare variables
+ * inside for() loop, bound to for() loop lifetime. It also utilizes GCC
+ * extension: __attribute__((cleanup(<func>))), supported by both GCC and
+ * Clang.
+ */
+#define bpf_for_each(type, cur, args...) for (							\
+	/* initialize and define destructor */							\
+	struct bpf_iter_##type ___it __attribute__((aligned(8), /* enforce, just in case */,	\
+						    cleanup(bpf_iter_##type##_destroy))),	\
+	/* ___p pointer is just to call bpf_iter_##type##_new() *once* to init ___it */		\
+			       *___p __attribute__((unused)) = (				\
+					bpf_iter_##type##_new(&___it, ##args),			\
+	/* this is a workaround for Clang bug: it currently doesn't emit BTF */			\
+	/* for bpf_iter_##type##_destroy() when used from cleanup() attribute */		\
+					(void)bpf_iter_##type##_destroy, (void *)0);		\
+	/* iteration and termination check */							\
+	(((cur) = bpf_iter_##type##_next(&___it)));						\
+)
+#endif /* bpf_for_each */
+
+#ifndef bpf_for
+/* bpf_for(i, start, end) implements a for()-like looping construct that sets
+ * provided integer variable *i* to values starting from *start* through,
+ * but not including, *end*. It also proves to BPF verifier that *i* belongs
+ * to range [start, end), so this can be used for accessing arrays without
+ * extra checks.
+ *
+ * Note: *start* and *end* are assumed to be expressions with no side effects
+ * and whose values do not change throughout bpf_for() loop execution. They do
+ * not have to be statically known or constant, though.
+ *
+ * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for()
+ * loop bound variables and cleanup attribute, supported by GCC and Clang.
+ */
+#define bpf_for(i, start, end) for (								\
+	/* initialize and define destructor */							\
+	struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */	\
+						 cleanup(bpf_iter_num_destroy))),		\
+	/* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */		\
+			    *___p __attribute__((unused)) = (					\
+				bpf_iter_num_new(&___it, (start), (end)),			\
+	/* this is a workaround for Clang bug: it currently doesn't emit BTF */			\
+	/* for bpf_iter_num_destroy() when used from cleanup() attribute */			\
+				(void)bpf_iter_num_destroy, (void *)0);				\
+	({											\
+		/* iteration step */								\
+		int *___t = bpf_iter_num_next(&___it);						\
+		/* termination and bounds check */						\
+		(___t && ((i) = *___t, (i) >= (start) && (i) < (end)));				\
+	});											\
+)
+#endif /* bpf_for */
+
+#ifndef bpf_repeat
+/* bpf_repeat(N) performs N iterations without exposing iteration number
+ *
+ * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for()
+ * loop bound variables and cleanup attribute, supported by GCC and Clang.
+ */
+#define bpf_repeat(N) for (									\
+	/* initialize and define destructor */							\
+	struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */	\
+						 cleanup(bpf_iter_num_destroy))),		\
+	/* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */		\
+			    *___p __attribute__((unused)) = (					\
+				bpf_iter_num_new(&___it, 0, (N)),				\
+	/* this is a workaround for Clang bug: it currently doesn't emit BTF */			\
+	/* for bpf_iter_num_destroy() when used from cleanup() attribute */			\
+				(void)bpf_iter_num_destroy, (void *)0);				\
+	bpf_iter_num_next(&___it);								\
+	/* nothing here  */									\
+)
+#endif /* bpf_repeat */
+
+#endif
diff --git a/tools/lib/bpf/bpf_prog_linfo.c b/tools/lib/bpf/bpf_prog_linfo.c
new file mode 100644
index 000000000..5c503096e
--- /dev/null
+++ b/tools/lib/bpf/bpf_prog_linfo.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2018 Facebook */
+
+#include <string.h>
+#include <stdlib.h>
+#include <linux/err.h>
+#include <linux/bpf.h>
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+struct bpf_prog_linfo {
+	void *raw_linfo;
+	void *raw_jited_linfo;
+	__u32 *nr_jited_linfo_per_func;
+	__u32 *jited_linfo_func_idx;
+	__u32 nr_linfo;
+	__u32 nr_jited_func;
+	__u32 rec_size;
+	__u32 jited_rec_size;
+};
+
+static int dissect_jited_func(struct bpf_prog_linfo *prog_linfo,
+			      const __u64 *ksym_func, const __u32 *ksym_len)
+{
+	__u32 nr_jited_func, nr_linfo;
+	const void *raw_jited_linfo;
+	const __u64 *jited_linfo;
+	__u64 last_jited_linfo;
+	/*
+	 * Index to raw_jited_linfo:
+	 *      i: Index for searching the next ksym_func
+	 * prev_i: Index to the last found ksym_func
+	 */
+	__u32 i, prev_i;
+	__u32 f; /* Index to ksym_func */
+
+	raw_jited_linfo = prog_linfo->raw_jited_linfo;
+	jited_linfo = raw_jited_linfo;
+	if (ksym_func[0] != *jited_linfo)
+		goto errout;
+
+	prog_linfo->jited_linfo_func_idx[0] = 0;
+	nr_jited_func = prog_linfo->nr_jited_func;
+	nr_linfo = prog_linfo->nr_linfo;
+
+	for (prev_i = 0, i = 1, f = 1;
+	     i < nr_linfo && f < nr_jited_func;
+	     i++) {
+		raw_jited_linfo += prog_linfo->jited_rec_size;
+		last_jited_linfo = *jited_linfo;
+		jited_linfo = raw_jited_linfo;
+
+		if (ksym_func[f] == *jited_linfo) {
+			prog_linfo->jited_linfo_func_idx[f] = i;
+
+			/* Sanity check */
+			if (last_jited_linfo - ksym_func[f - 1] + 1 >
+			    ksym_len[f - 1])
+				goto errout;
+
+			prog_linfo->nr_jited_linfo_per_func[f - 1] =
+				i - prev_i;
+			prev_i = i;
+
+			/*
+			 * The ksym_func[f] is found in jited_linfo.
+			 * Look for the next one.
+			 */
+			f++;
+		} else if (*jited_linfo <= last_jited_linfo) {
+			/* Ensure the addr is increasing _within_ a func */
+			goto errout;
+		}
+	}
+
+	if (f != nr_jited_func)
+		goto errout;
+
+	prog_linfo->nr_jited_linfo_per_func[nr_jited_func - 1] =
+		nr_linfo - prev_i;
+
+	return 0;
+
+errout:
+	return -EINVAL;
+}
+
+void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo)
+{
+	if (!prog_linfo)
+		return;
+
+	free(prog_linfo->raw_linfo);
+	free(prog_linfo->raw_jited_linfo);
+	free(prog_linfo->nr_jited_linfo_per_func);
+	free(prog_linfo->jited_linfo_func_idx);
+	free(prog_linfo);
+}
+
+struct bpf_prog_linfo *bpf_prog_linfo__new(const struct bpf_prog_info *info)
+{
+	struct bpf_prog_linfo *prog_linfo;
+	__u32 nr_linfo, nr_jited_func;
+	__u64 data_sz;
+
+	nr_linfo = info->nr_line_info;
+
+	if (!nr_linfo)
+		return errno = EINVAL, NULL;
+
+	/*
+	 * The min size that bpf_prog_linfo has to access for
+	 * searching purpose.
+	 */
+	if (info->line_info_rec_size <
+	    offsetof(struct bpf_line_info, file_name_off))
+		return errno = EINVAL, NULL;
+
+	prog_linfo = calloc(1, sizeof(*prog_linfo));
+	if (!prog_linfo)
+		return errno = ENOMEM, NULL;
+
+	/* Copy xlated line_info */
+	prog_linfo->nr_linfo = nr_linfo;
+	prog_linfo->rec_size = info->line_info_rec_size;
+	data_sz = (__u64)nr_linfo * prog_linfo->rec_size;
+	prog_linfo->raw_linfo = malloc(data_sz);
+	if (!prog_linfo->raw_linfo)
+		goto err_free;
+	memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info, data_sz);
+
+	nr_jited_func = info->nr_jited_ksyms;
+	if (!nr_jited_func ||
+	    !info->jited_line_info ||
+	    info->nr_jited_line_info != nr_linfo ||
+	    info->jited_line_info_rec_size < sizeof(__u64) ||
+	    info->nr_jited_func_lens != nr_jited_func ||
+	    !info->jited_ksyms ||
+	    !info->jited_func_lens)
+		/* Not enough info to provide jited_line_info */
+		return prog_linfo;
+
+	/* Copy jited_line_info */
+	prog_linfo->nr_jited_func = nr_jited_func;
+	prog_linfo->jited_rec_size = info->jited_line_info_rec_size;
+	data_sz = (__u64)nr_linfo * prog_linfo->jited_rec_size;
+	prog_linfo->raw_jited_linfo = malloc(data_sz);
+	if (!prog_linfo->raw_jited_linfo)
+		goto err_free;
+	memcpy(prog_linfo->raw_jited_linfo,
+	       (void *)(long)info->jited_line_info, data_sz);
+
+	/* Number of jited_line_info per jited func */
+	prog_linfo->nr_jited_linfo_per_func = malloc(nr_jited_func *
+						     sizeof(__u32));
+	if (!prog_linfo->nr_jited_linfo_per_func)
+		goto err_free;
+
+	/*
+	 * For each jited func,
+	 * the start idx to the "linfo" and "jited_linfo" array,
+	 */
+	prog_linfo->jited_linfo_func_idx = malloc(nr_jited_func *
+						  sizeof(__u32));
+	if (!prog_linfo->jited_linfo_func_idx)
+		goto err_free;
+
+	if (dissect_jited_func(prog_linfo,
+			       (__u64 *)(long)info->jited_ksyms,
+			       (__u32 *)(long)info->jited_func_lens))
+		goto err_free;
+
+	return prog_linfo;
+
+err_free:
+	bpf_prog_linfo__free(prog_linfo);
+	return errno = EINVAL, NULL;
+}
+
+const struct bpf_line_info *
+bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo,
+				__u64 addr, __u32 func_idx, __u32 nr_skip)
+{
+	__u32 jited_rec_size, rec_size, nr_linfo, start, i;
+	const void *raw_jited_linfo, *raw_linfo;
+	const __u64 *jited_linfo;
+
+	if (func_idx >= prog_linfo->nr_jited_func)
+		return errno = ENOENT, NULL;
+
+	nr_linfo = prog_linfo->nr_jited_linfo_per_func[func_idx];
+	if (nr_skip >= nr_linfo)
+		return errno = ENOENT, NULL;
+
+	start = prog_linfo->jited_linfo_func_idx[func_idx] + nr_skip;
+	jited_rec_size = prog_linfo->jited_rec_size;
+	raw_jited_linfo = prog_linfo->raw_jited_linfo +
+		(start * jited_rec_size);
+	jited_linfo = raw_jited_linfo;
+	if (addr < *jited_linfo)
+		return errno = ENOENT, NULL;
+
+	nr_linfo -= nr_skip;
+	rec_size = prog_linfo->rec_size;
+	raw_linfo = prog_linfo->raw_linfo + (start * rec_size);
+	for (i = 0; i < nr_linfo; i++) {
+		if (addr < *jited_linfo)
+			break;
+
+		raw_linfo += rec_size;
+		raw_jited_linfo += jited_rec_size;
+		jited_linfo = raw_jited_linfo;
+	}
+
+	return raw_linfo - rec_size;
+}
+
+const struct bpf_line_info *
+bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo,
+		      __u32 insn_off, __u32 nr_skip)
+{
+	const struct bpf_line_info *linfo;
+	__u32 rec_size, nr_linfo, i;
+	const void *raw_linfo;
+
+	nr_linfo = prog_linfo->nr_linfo;
+	if (nr_skip >= nr_linfo)
+		return errno = ENOENT, NULL;
+
+	rec_size = prog_linfo->rec_size;
+	raw_linfo = prog_linfo->raw_linfo + (nr_skip * rec_size);
+	linfo = raw_linfo;
+	if (insn_off < linfo->insn_off)
+		return errno = ENOENT, NULL;
+
+	nr_linfo -= nr_skip;
+	for (i = 0; i < nr_linfo; i++) {
+		if (insn_off < linfo->insn_off)
+			break;
+
+		raw_linfo += rec_size;
+		linfo = raw_linfo;
+	}
+
+	return raw_linfo - rec_size;
+}
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
new file mode 100644
index 000000000..dbe32a5d0
--- /dev/null
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -0,0 +1,929 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __BPF_TRACING_H__
+#define __BPF_TRACING_H__
+
+#include "bpf_helpers.h"
+
+/* Scan the ARCH passed in from ARCH env variable (see Makefile) */
+#if defined(__TARGET_ARCH_x86)
+	#define bpf_target_x86
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_s390)
+	#define bpf_target_s390
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arm)
+	#define bpf_target_arm
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arm64)
+	#define bpf_target_arm64
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_mips)
+	#define bpf_target_mips
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_powerpc)
+	#define bpf_target_powerpc
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_sparc)
+	#define bpf_target_sparc
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_riscv)
+	#define bpf_target_riscv
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arc)
+	#define bpf_target_arc
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_loongarch)
+	#define bpf_target_loongarch
+	#define bpf_target_defined
+#else
+
+/* Fall back to what the compiler says */
+#if defined(__x86_64__)
+	#define bpf_target_x86
+	#define bpf_target_defined
+#elif defined(__s390__)
+	#define bpf_target_s390
+	#define bpf_target_defined
+#elif defined(__arm__)
+	#define bpf_target_arm
+	#define bpf_target_defined
+#elif defined(__aarch64__)
+	#define bpf_target_arm64
+	#define bpf_target_defined
+#elif defined(__mips__)
+	#define bpf_target_mips
+	#define bpf_target_defined
+#elif defined(__powerpc__)
+	#define bpf_target_powerpc
+	#define bpf_target_defined
+#elif defined(__sparc__)
+	#define bpf_target_sparc
+	#define bpf_target_defined
+#elif defined(__riscv) && __riscv_xlen == 64
+	#define bpf_target_riscv
+	#define bpf_target_defined
+#elif defined(__arc__)
+	#define bpf_target_arc
+	#define bpf_target_defined
+#elif defined(__loongarch__)
+	#define bpf_target_loongarch
+	#define bpf_target_defined
+#endif /* no compiler target */
+
+#endif
+
+#ifndef __BPF_TARGET_MISSING
+#define __BPF_TARGET_MISSING "GCC error \"Must specify a BPF target arch via __TARGET_ARCH_xxx\""
+#endif
+
+#if defined(bpf_target_x86)
+
+/*
+ * https://en.wikipedia.org/wiki/X86_calling_conventions#System_V_AMD64_ABI
+ */
+
+#if defined(__KERNEL__) || defined(__VMLINUX_H__)
+
+#define __PT_PARM1_REG di
+#define __PT_PARM2_REG si
+#define __PT_PARM3_REG dx
+#define __PT_PARM4_REG cx
+#define __PT_PARM5_REG r8
+#define __PT_PARM6_REG r9
+/*
+ * Syscall uses r10 for PARM4. See arch/x86/entry/entry_64.S:entry_SYSCALL_64
+ * comments in Linux sources. And refer to syscall(2) manpage.
+ */
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG r10
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+
+#define __PT_RET_REG sp
+#define __PT_FP_REG bp
+#define __PT_RC_REG ax
+#define __PT_SP_REG sp
+#define __PT_IP_REG ip
+
+#else
+
+#ifdef __i386__
+
+/* i386 kernel is built with -mregparm=3 */
+#define __PT_PARM1_REG eax
+#define __PT_PARM2_REG edx
+#define __PT_PARM3_REG ecx
+/* i386 syscall ABI is very different, refer to syscall(2) manpage */
+#define __PT_PARM1_SYSCALL_REG ebx
+#define __PT_PARM2_SYSCALL_REG ecx
+#define __PT_PARM3_SYSCALL_REG edx
+#define __PT_PARM4_SYSCALL_REG esi
+#define __PT_PARM5_SYSCALL_REG edi
+#define __PT_PARM6_SYSCALL_REG ebp
+
+#define __PT_RET_REG esp
+#define __PT_FP_REG ebp
+#define __PT_RC_REG eax
+#define __PT_SP_REG esp
+#define __PT_IP_REG eip
+
+#else /* __i386__ */
+
+#define __PT_PARM1_REG rdi
+#define __PT_PARM2_REG rsi
+#define __PT_PARM3_REG rdx
+#define __PT_PARM4_REG rcx
+#define __PT_PARM5_REG r8
+#define __PT_PARM6_REG r9
+
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG r10
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+
+#define __PT_RET_REG rsp
+#define __PT_FP_REG rbp
+#define __PT_RC_REG rax
+#define __PT_SP_REG rsp
+#define __PT_IP_REG rip
+
+#endif /* __i386__ */
+
+#endif /* __KERNEL__ || __VMLINUX_H__ */
+
+#elif defined(bpf_target_s390)
+
+/*
+ * https://github.com/IBM/s390x-abi/releases/download/v1.6/lzsabi_s390x.pdf
+ */
+
+struct pt_regs___s390 {
+	unsigned long orig_gpr2;
+} __attribute__((preserve_access_index));
+
+/* s390 provides user_pt_regs instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const user_pt_regs *)(x))
+#define __PT_PARM1_REG gprs[2]
+#define __PT_PARM2_REG gprs[3]
+#define __PT_PARM3_REG gprs[4]
+#define __PT_PARM4_REG gprs[5]
+#define __PT_PARM5_REG gprs[6]
+
+#define __PT_PARM1_SYSCALL_REG orig_gpr2
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG gprs[7]
+#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___s390 *)(x))->__PT_PARM1_SYSCALL_REG)
+#define PT_REGS_PARM1_CORE_SYSCALL(x) \
+	BPF_CORE_READ((const struct pt_regs___s390 *)(x), __PT_PARM1_SYSCALL_REG)
+
+#define __PT_RET_REG gprs[14]
+#define __PT_FP_REG gprs[11]	/* Works only with CONFIG_FRAME_POINTER */
+#define __PT_RC_REG gprs[2]
+#define __PT_SP_REG gprs[15]
+#define __PT_IP_REG psw.addr
+
+#elif defined(bpf_target_arm)
+
+/*
+ * https://github.com/ARM-software/abi-aa/blob/main/aapcs32/aapcs32.rst#machine-registers
+ */
+
+#define __PT_PARM1_REG uregs[0]
+#define __PT_PARM2_REG uregs[1]
+#define __PT_PARM3_REG uregs[2]
+#define __PT_PARM4_REG uregs[3]
+
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG uregs[4]
+#define __PT_PARM6_SYSCALL_REG uregs[5]
+#define __PT_PARM7_SYSCALL_REG uregs[6]
+
+#define __PT_RET_REG uregs[14]
+#define __PT_FP_REG uregs[11]	/* Works only with CONFIG_FRAME_POINTER */
+#define __PT_RC_REG uregs[0]
+#define __PT_SP_REG uregs[13]
+#define __PT_IP_REG uregs[12]
+
+#elif defined(bpf_target_arm64)
+
+/*
+ * https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#machine-registers
+ */
+
+struct pt_regs___arm64 {
+	unsigned long orig_x0;
+} __attribute__((preserve_access_index));
+
+/* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x))
+#define __PT_PARM1_REG regs[0]
+#define __PT_PARM2_REG regs[1]
+#define __PT_PARM3_REG regs[2]
+#define __PT_PARM4_REG regs[3]
+#define __PT_PARM5_REG regs[4]
+#define __PT_PARM6_REG regs[5]
+#define __PT_PARM7_REG regs[6]
+#define __PT_PARM8_REG regs[7]
+
+#define __PT_PARM1_SYSCALL_REG orig_x0
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___arm64 *)(x))->__PT_PARM1_SYSCALL_REG)
+#define PT_REGS_PARM1_CORE_SYSCALL(x) \
+	BPF_CORE_READ((const struct pt_regs___arm64 *)(x), __PT_PARM1_SYSCALL_REG)
+
+#define __PT_RET_REG regs[30]
+#define __PT_FP_REG regs[29]	/* Works only with CONFIG_FRAME_POINTER */
+#define __PT_RC_REG regs[0]
+#define __PT_SP_REG sp
+#define __PT_IP_REG pc
+
+#elif defined(bpf_target_mips)
+
+/*
+ * N64 ABI is assumed right now.
+ * https://en.wikipedia.org/wiki/MIPS_architecture#Calling_conventions
+ */
+
+#define __PT_PARM1_REG regs[4]
+#define __PT_PARM2_REG regs[5]
+#define __PT_PARM3_REG regs[6]
+#define __PT_PARM4_REG regs[7]
+#define __PT_PARM5_REG regs[8]
+#define __PT_PARM6_REG regs[9]
+#define __PT_PARM7_REG regs[10]
+#define __PT_PARM8_REG regs[11]
+
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG /* only N32/N64 */
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG /* only N32/N64 */
+
+#define __PT_RET_REG regs[31]
+#define __PT_FP_REG regs[30]	/* Works only with CONFIG_FRAME_POINTER */
+#define __PT_RC_REG regs[2]
+#define __PT_SP_REG regs[29]
+#define __PT_IP_REG cp0_epc
+
+#elif defined(bpf_target_powerpc)
+
+/*
+ * http://refspecs.linux-foundation.org/elf/elfspec_ppc.pdf (page 3-14,
+ * section "Function Calling Sequence")
+ */
+
+#define __PT_PARM1_REG gpr[3]
+#define __PT_PARM2_REG gpr[4]
+#define __PT_PARM3_REG gpr[5]
+#define __PT_PARM4_REG gpr[6]
+#define __PT_PARM5_REG gpr[7]
+#define __PT_PARM6_REG gpr[8]
+#define __PT_PARM7_REG gpr[9]
+#define __PT_PARM8_REG gpr[10]
+
+/* powerpc does not select ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ctx
+#define __PT_PARM1_SYSCALL_REG orig_gpr3
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+#if !defined(__arch64__)
+#define __PT_PARM7_SYSCALL_REG __PT_PARM7_REG /* only powerpc (not powerpc64) */
+#endif
+
+#define __PT_RET_REG regs[31]
+#define __PT_FP_REG __unsupported__
+#define __PT_RC_REG gpr[3]
+#define __PT_SP_REG gpr[1]
+#define __PT_IP_REG nip
+
+#elif defined(bpf_target_sparc)
+
+/*
+ * https://en.wikipedia.org/wiki/Calling_convention#SPARC
+ */
+
+#define __PT_PARM1_REG u_regs[UREG_I0]
+#define __PT_PARM2_REG u_regs[UREG_I1]
+#define __PT_PARM3_REG u_regs[UREG_I2]
+#define __PT_PARM4_REG u_regs[UREG_I3]
+#define __PT_PARM5_REG u_regs[UREG_I4]
+#define __PT_PARM6_REG u_regs[UREG_I5]
+
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+
+#define __PT_RET_REG u_regs[UREG_I7]
+#define __PT_FP_REG __unsupported__
+#define __PT_RC_REG u_regs[UREG_I0]
+#define __PT_SP_REG u_regs[UREG_FP]
+/* Should this also be a bpf_target check for the sparc case? */
+#if defined(__arch64__)
+#define __PT_IP_REG tpc
+#else
+#define __PT_IP_REG pc
+#endif
+
+#elif defined(bpf_target_riscv)
+
+/*
+ * https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc#risc-v-calling-conventions
+ */
+
+struct pt_regs___riscv {
+	unsigned long orig_a0;
+} __attribute__((preserve_access_index));
+
+/* riscv provides struct user_regs_struct instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
+#define __PT_PARM1_REG a0
+#define __PT_PARM2_REG a1
+#define __PT_PARM3_REG a2
+#define __PT_PARM4_REG a3
+#define __PT_PARM5_REG a4
+#define __PT_PARM6_REG a5
+#define __PT_PARM7_REG a6
+#define __PT_PARM8_REG a7
+
+#define __PT_PARM1_SYSCALL_REG orig_a0
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___riscv *)(x))->__PT_PARM1_SYSCALL_REG)
+#define PT_REGS_PARM1_CORE_SYSCALL(x) \
+	BPF_CORE_READ((const struct pt_regs___riscv *)(x), __PT_PARM1_SYSCALL_REG)
+
+#define __PT_RET_REG ra
+#define __PT_FP_REG s0
+#define __PT_RC_REG a0
+#define __PT_SP_REG sp
+#define __PT_IP_REG pc
+
+#elif defined(bpf_target_arc)
+
+/*
+ * Section "Function Calling Sequence" (page 24):
+ * https://raw.githubusercontent.com/wiki/foss-for-synopsys-dwc-arc-processors/toolchain/files/ARCv2_ABI.pdf
+ */
+
+/* arc provides struct user_regs_struct instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
+#define __PT_PARM1_REG scratch.r0
+#define __PT_PARM2_REG scratch.r1
+#define __PT_PARM3_REG scratch.r2
+#define __PT_PARM4_REG scratch.r3
+#define __PT_PARM5_REG scratch.r4
+#define __PT_PARM6_REG scratch.r5
+#define __PT_PARM7_REG scratch.r6
+#define __PT_PARM8_REG scratch.r7
+
+/* arc does not select ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ctx
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+
+#define __PT_RET_REG scratch.blink
+#define __PT_FP_REG scratch.fp
+#define __PT_RC_REG scratch.r0
+#define __PT_SP_REG scratch.sp
+#define __PT_IP_REG scratch.ret
+
+#elif defined(bpf_target_loongarch)
+
+/*
+ * https://docs.kernel.org/loongarch/introduction.html
+ * https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html
+ */
+
+/* loongarch provides struct user_pt_regs instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x))
+#define __PT_PARM1_REG regs[4]
+#define __PT_PARM2_REG regs[5]
+#define __PT_PARM3_REG regs[6]
+#define __PT_PARM4_REG regs[7]
+#define __PT_PARM5_REG regs[8]
+#define __PT_PARM6_REG regs[9]
+#define __PT_PARM7_REG regs[10]
+#define __PT_PARM8_REG regs[11]
+
+/* loongarch does not select ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ctx
+#define __PT_PARM1_SYSCALL_REG __PT_PARM1_REG
+#define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
+#define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
+#define __PT_PARM4_SYSCALL_REG __PT_PARM4_REG
+#define __PT_PARM5_SYSCALL_REG __PT_PARM5_REG
+#define __PT_PARM6_SYSCALL_REG __PT_PARM6_REG
+
+#define __PT_RET_REG regs[1]
+#define __PT_FP_REG regs[22]
+#define __PT_RC_REG regs[4]
+#define __PT_SP_REG regs[3]
+#define __PT_IP_REG csr_era
+
+#endif
+
+#if defined(bpf_target_defined)
+
+struct pt_regs;
+
+/* allow some architectures to override `struct pt_regs` */
+#ifndef __PT_REGS_CAST
+#define __PT_REGS_CAST(x) (x)
+#endif
+
+/*
+ * Different architectures support different number of arguments passed
+ * through registers. i386 supports just 3, some arches support up to 8.
+ */
+#ifndef __PT_PARM4_REG
+#define __PT_PARM4_REG __unsupported__
+#endif
+#ifndef __PT_PARM5_REG
+#define __PT_PARM5_REG __unsupported__
+#endif
+#ifndef __PT_PARM6_REG
+#define __PT_PARM6_REG __unsupported__
+#endif
+#ifndef __PT_PARM7_REG
+#define __PT_PARM7_REG __unsupported__
+#endif
+#ifndef __PT_PARM8_REG
+#define __PT_PARM8_REG __unsupported__
+#endif
+/*
+ * Similarly, syscall-specific conventions might differ between function call
+ * conventions within each architecture. All supported architectures pass
+ * either 6 or 7 syscall arguments in registers.
+ *
+ * See syscall(2) manpage for succinct table with information on each arch.
+ */
+#ifndef __PT_PARM7_SYSCALL_REG
+#define __PT_PARM7_SYSCALL_REG __unsupported__
+#endif
+
+#define PT_REGS_PARM1(x) (__PT_REGS_CAST(x)->__PT_PARM1_REG)
+#define PT_REGS_PARM2(x) (__PT_REGS_CAST(x)->__PT_PARM2_REG)
+#define PT_REGS_PARM3(x) (__PT_REGS_CAST(x)->__PT_PARM3_REG)
+#define PT_REGS_PARM4(x) (__PT_REGS_CAST(x)->__PT_PARM4_REG)
+#define PT_REGS_PARM5(x) (__PT_REGS_CAST(x)->__PT_PARM5_REG)
+#define PT_REGS_PARM6(x) (__PT_REGS_CAST(x)->__PT_PARM6_REG)
+#define PT_REGS_PARM7(x) (__PT_REGS_CAST(x)->__PT_PARM7_REG)
+#define PT_REGS_PARM8(x) (__PT_REGS_CAST(x)->__PT_PARM8_REG)
+#define PT_REGS_RET(x) (__PT_REGS_CAST(x)->__PT_RET_REG)
+#define PT_REGS_FP(x) (__PT_REGS_CAST(x)->__PT_FP_REG)
+#define PT_REGS_RC(x) (__PT_REGS_CAST(x)->__PT_RC_REG)
+#define PT_REGS_SP(x) (__PT_REGS_CAST(x)->__PT_SP_REG)
+#define PT_REGS_IP(x) (__PT_REGS_CAST(x)->__PT_IP_REG)
+
+#define PT_REGS_PARM1_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM1_REG)
+#define PT_REGS_PARM2_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM2_REG)
+#define PT_REGS_PARM3_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM3_REG)
+#define PT_REGS_PARM4_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM4_REG)
+#define PT_REGS_PARM5_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM5_REG)
+#define PT_REGS_PARM6_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM6_REG)
+#define PT_REGS_PARM7_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM7_REG)
+#define PT_REGS_PARM8_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM8_REG)
+#define PT_REGS_RET_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_RET_REG)
+#define PT_REGS_FP_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_FP_REG)
+#define PT_REGS_RC_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_RC_REG)
+#define PT_REGS_SP_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_SP_REG)
+#define PT_REGS_IP_CORE(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_IP_REG)
+
+#if defined(bpf_target_powerpc)
+
+#define BPF_KPROBE_READ_RET_IP(ip, ctx)		({ (ip) = (ctx)->link; })
+#define BPF_KRETPROBE_READ_RET_IP		BPF_KPROBE_READ_RET_IP
+
+#elif defined(bpf_target_sparc) || defined(bpf_target_arm64)
+
+#define BPF_KPROBE_READ_RET_IP(ip, ctx)		({ (ip) = PT_REGS_RET(ctx); })
+#define BPF_KRETPROBE_READ_RET_IP		BPF_KPROBE_READ_RET_IP
+
+#else
+
+#define BPF_KPROBE_READ_RET_IP(ip, ctx)					    \
+	({ bpf_probe_read_kernel(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)); })
+#define BPF_KRETPROBE_READ_RET_IP(ip, ctx)				    \
+	({ bpf_probe_read_kernel(&(ip), sizeof(ip), (void *)(PT_REGS_FP(ctx) + sizeof(ip))); })
+
+#endif
+
+#ifndef PT_REGS_PARM1_SYSCALL
+#define PT_REGS_PARM1_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM1_SYSCALL_REG)
+#define PT_REGS_PARM1_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM1_SYSCALL_REG)
+#endif
+#ifndef PT_REGS_PARM2_SYSCALL
+#define PT_REGS_PARM2_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM2_SYSCALL_REG)
+#define PT_REGS_PARM2_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM2_SYSCALL_REG)
+#endif
+#ifndef PT_REGS_PARM3_SYSCALL
+#define PT_REGS_PARM3_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM3_SYSCALL_REG)
+#define PT_REGS_PARM3_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM3_SYSCALL_REG)
+#endif
+#ifndef PT_REGS_PARM4_SYSCALL
+#define PT_REGS_PARM4_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM4_SYSCALL_REG)
+#define PT_REGS_PARM4_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM4_SYSCALL_REG)
+#endif
+#ifndef PT_REGS_PARM5_SYSCALL
+#define PT_REGS_PARM5_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM5_SYSCALL_REG)
+#define PT_REGS_PARM5_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM5_SYSCALL_REG)
+#endif
+#ifndef PT_REGS_PARM6_SYSCALL
+#define PT_REGS_PARM6_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM6_SYSCALL_REG)
+#define PT_REGS_PARM6_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM6_SYSCALL_REG)
+#endif
+#ifndef PT_REGS_PARM7_SYSCALL
+#define PT_REGS_PARM7_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM7_SYSCALL_REG)
+#define PT_REGS_PARM7_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM7_SYSCALL_REG)
+#endif
+
+#else /* defined(bpf_target_defined) */
+
+#define PT_REGS_PARM1(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM6(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM7(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM8(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_RET(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_FP(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_RC(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_SP(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_IP(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#define PT_REGS_PARM1_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM6_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM7_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM8_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_RET_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_FP_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_RC_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_SP_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_IP_CORE(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#define BPF_KPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define BPF_KRETPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#define PT_REGS_PARM1_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM6_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM7_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#define PT_REGS_PARM1_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM6_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM7_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#endif /* defined(bpf_target_defined) */
+
+/*
+ * When invoked from a syscall handler kprobe, returns a pointer to a
+ * struct pt_regs containing syscall arguments and suitable for passing to
+ * PT_REGS_PARMn_SYSCALL() and PT_REGS_PARMn_CORE_SYSCALL().
+ */
+#ifndef PT_REGS_SYSCALL_REGS
+/* By default, assume that the arch selects ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ((struct pt_regs *)PT_REGS_PARM1(ctx))
+#endif
+
+#ifndef ___bpf_concat
+#define ___bpf_concat(a, b) a ## b
+#endif
+#ifndef ___bpf_apply
+#define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
+#endif
+#ifndef ___bpf_nth
+#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
+#endif
+#ifndef ___bpf_narg
+#define ___bpf_narg(...) ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+#endif
+
+#define ___bpf_ctx_cast0()            ctx
+#define ___bpf_ctx_cast1(x)           ___bpf_ctx_cast0(), ctx[0]
+#define ___bpf_ctx_cast2(x, args...)  ___bpf_ctx_cast1(args), ctx[1]
+#define ___bpf_ctx_cast3(x, args...)  ___bpf_ctx_cast2(args), ctx[2]
+#define ___bpf_ctx_cast4(x, args...)  ___bpf_ctx_cast3(args), ctx[3]
+#define ___bpf_ctx_cast5(x, args...)  ___bpf_ctx_cast4(args), ctx[4]
+#define ___bpf_ctx_cast6(x, args...)  ___bpf_ctx_cast5(args), ctx[5]
+#define ___bpf_ctx_cast7(x, args...)  ___bpf_ctx_cast6(args), ctx[6]
+#define ___bpf_ctx_cast8(x, args...)  ___bpf_ctx_cast7(args), ctx[7]
+#define ___bpf_ctx_cast9(x, args...)  ___bpf_ctx_cast8(args), ctx[8]
+#define ___bpf_ctx_cast10(x, args...) ___bpf_ctx_cast9(args), ctx[9]
+#define ___bpf_ctx_cast11(x, args...) ___bpf_ctx_cast10(args), ctx[10]
+#define ___bpf_ctx_cast12(x, args...) ___bpf_ctx_cast11(args), ctx[11]
+#define ___bpf_ctx_cast(args...)      ___bpf_apply(___bpf_ctx_cast, ___bpf_narg(args))(args)
+
+/*
+ * BPF_PROG is a convenience wrapper for generic tp_btf/fentry/fexit and
+ * similar kinds of BPF programs, that accept input arguments as a single
+ * pointer to untyped u64 array, where each u64 can actually be a typed
+ * pointer or integer of different size. Instead of requiring user to write
+ * manual casts and work with array elements by index, BPF_PROG macro
+ * allows user to declare a list of named and typed input arguments in the
+ * same syntax as for normal C function. All the casting is hidden and
+ * performed transparently, while user code can just assume working with
+ * function arguments of specified type and name.
+ *
+ * Original raw context argument is preserved as well as 'ctx' argument.
+ * This is useful when using BPF helpers that expect original context
+ * as one of the parameters (e.g., for bpf_perf_event_output()).
+ */
+#define BPF_PROG(name, args...)						    \
+name(unsigned long long *ctx);						    \
+static __always_inline typeof(name(0))					    \
+____##name(unsigned long long *ctx, ##args);				    \
+typeof(name(0)) name(unsigned long long *ctx)				    \
+{									    \
+	_Pragma("GCC diagnostic push")					    \
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
+	return ____##name(___bpf_ctx_cast(args));			    \
+	_Pragma("GCC diagnostic pop")					    \
+}									    \
+static __always_inline typeof(name(0))					    \
+____##name(unsigned long long *ctx, ##args)
+
+#ifndef ___bpf_nth2
+#define ___bpf_nth2(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13,	\
+		    _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N
+#endif
+#ifndef ___bpf_narg2
+#define ___bpf_narg2(...)	\
+	___bpf_nth2(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7,	\
+		    6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0)
+#endif
+
+#define ___bpf_treg_cnt(t) \
+	__builtin_choose_expr(sizeof(t) == 1, 1,	\
+	__builtin_choose_expr(sizeof(t) == 2, 1,	\
+	__builtin_choose_expr(sizeof(t) == 4, 1,	\
+	__builtin_choose_expr(sizeof(t) == 8, 1,	\
+	__builtin_choose_expr(sizeof(t) == 16, 2,	\
+			      (void)0)))))
+
+#define ___bpf_reg_cnt0()		(0)
+#define ___bpf_reg_cnt1(t, x)		(___bpf_reg_cnt0() + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt2(t, x, args...)	(___bpf_reg_cnt1(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt3(t, x, args...)	(___bpf_reg_cnt2(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt4(t, x, args...)	(___bpf_reg_cnt3(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt5(t, x, args...)	(___bpf_reg_cnt4(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt6(t, x, args...)	(___bpf_reg_cnt5(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt7(t, x, args...)	(___bpf_reg_cnt6(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt8(t, x, args...)	(___bpf_reg_cnt7(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt9(t, x, args...)	(___bpf_reg_cnt8(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt10(t, x, args...)	(___bpf_reg_cnt9(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt11(t, x, args...)	(___bpf_reg_cnt10(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt12(t, x, args...)	(___bpf_reg_cnt11(args) + ___bpf_treg_cnt(t))
+#define ___bpf_reg_cnt(args...)	 ___bpf_apply(___bpf_reg_cnt, ___bpf_narg2(args))(args)
+
+#define ___bpf_union_arg(t, x, n) \
+	__builtin_choose_expr(sizeof(t) == 1, ({ union { __u8 z[1]; t x; } ___t = { .z = {ctx[n]}}; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 2, ({ union { __u16 z[1]; t x; } ___t = { .z = {ctx[n]} }; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 4, ({ union { __u32 z[1]; t x; } ___t = { .z = {ctx[n]} }; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 8, ({ union { __u64 z[1]; t x; } ___t = {.z = {ctx[n]} }; ___t.x; }), \
+	__builtin_choose_expr(sizeof(t) == 16, ({ union { __u64 z[2]; t x; } ___t = {.z = {ctx[n], ctx[n + 1]} }; ___t.x; }), \
+			      (void)0)))))
+
+#define ___bpf_ctx_arg0(n, args...)
+#define ___bpf_ctx_arg1(n, t, x)		, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt1(t, x))
+#define ___bpf_ctx_arg2(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt2(t, x, args)) ___bpf_ctx_arg1(n, args)
+#define ___bpf_ctx_arg3(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt3(t, x, args)) ___bpf_ctx_arg2(n, args)
+#define ___bpf_ctx_arg4(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt4(t, x, args)) ___bpf_ctx_arg3(n, args)
+#define ___bpf_ctx_arg5(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt5(t, x, args)) ___bpf_ctx_arg4(n, args)
+#define ___bpf_ctx_arg6(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt6(t, x, args)) ___bpf_ctx_arg5(n, args)
+#define ___bpf_ctx_arg7(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt7(t, x, args)) ___bpf_ctx_arg6(n, args)
+#define ___bpf_ctx_arg8(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt8(t, x, args)) ___bpf_ctx_arg7(n, args)
+#define ___bpf_ctx_arg9(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt9(t, x, args)) ___bpf_ctx_arg8(n, args)
+#define ___bpf_ctx_arg10(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt10(t, x, args)) ___bpf_ctx_arg9(n, args)
+#define ___bpf_ctx_arg11(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt11(t, x, args)) ___bpf_ctx_arg10(n, args)
+#define ___bpf_ctx_arg12(n, t, x, args...)	, ___bpf_union_arg(t, x, n - ___bpf_reg_cnt12(t, x, args)) ___bpf_ctx_arg11(n, args)
+#define ___bpf_ctx_arg(args...)	___bpf_apply(___bpf_ctx_arg, ___bpf_narg2(args))(___bpf_reg_cnt(args), args)
+
+#define ___bpf_ctx_decl0()
+#define ___bpf_ctx_decl1(t, x)			, t x
+#define ___bpf_ctx_decl2(t, x, args...)		, t x ___bpf_ctx_decl1(args)
+#define ___bpf_ctx_decl3(t, x, args...)		, t x ___bpf_ctx_decl2(args)
+#define ___bpf_ctx_decl4(t, x, args...)		, t x ___bpf_ctx_decl3(args)
+#define ___bpf_ctx_decl5(t, x, args...)		, t x ___bpf_ctx_decl4(args)
+#define ___bpf_ctx_decl6(t, x, args...)		, t x ___bpf_ctx_decl5(args)
+#define ___bpf_ctx_decl7(t, x, args...)		, t x ___bpf_ctx_decl6(args)
+#define ___bpf_ctx_decl8(t, x, args...)		, t x ___bpf_ctx_decl7(args)
+#define ___bpf_ctx_decl9(t, x, args...)		, t x ___bpf_ctx_decl8(args)
+#define ___bpf_ctx_decl10(t, x, args...)	, t x ___bpf_ctx_decl9(args)
+#define ___bpf_ctx_decl11(t, x, args...)	, t x ___bpf_ctx_decl10(args)
+#define ___bpf_ctx_decl12(t, x, args...)	, t x ___bpf_ctx_decl11(args)
+#define ___bpf_ctx_decl(args...)	___bpf_apply(___bpf_ctx_decl, ___bpf_narg2(args))(args)
+
+/*
+ * BPF_PROG2 is an enhanced version of BPF_PROG in order to handle struct
+ * arguments. Since each struct argument might take one or two u64 values
+ * in the trampoline stack, argument type size is needed to place proper number
+ * of u64 values for each argument. Therefore, BPF_PROG2 has different
+ * syntax from BPF_PROG. For example, for the following BPF_PROG syntax:
+ *
+ *   int BPF_PROG(test2, int a, int b) { ... }
+ *
+ * the corresponding BPF_PROG2 syntax is:
+ *
+ *   int BPF_PROG2(test2, int, a, int, b) { ... }
+ *
+ * where type and the corresponding argument name are separated by comma.
+ *
+ * Use BPF_PROG2 macro if one of the arguments might be a struct/union larger
+ * than 8 bytes:
+ *
+ *   int BPF_PROG2(test_struct_arg, struct bpf_testmod_struct_arg_1, a, int, b,
+ *		   int, c, int, d, struct bpf_testmod_struct_arg_2, e, int, ret)
+ *   {
+ *        // access a, b, c, d, e, and ret directly
+ *        ...
+ *   }
+ */
+#define BPF_PROG2(name, args...)						\
+name(unsigned long long *ctx);							\
+static __always_inline typeof(name(0))						\
+____##name(unsigned long long *ctx ___bpf_ctx_decl(args));			\
+typeof(name(0)) name(unsigned long long *ctx)					\
+{										\
+	return ____##name(ctx ___bpf_ctx_arg(args));				\
+}										\
+static __always_inline typeof(name(0))						\
+____##name(unsigned long long *ctx ___bpf_ctx_decl(args))
+
+struct pt_regs;
+
+#define ___bpf_kprobe_args0()           ctx
+#define ___bpf_kprobe_args1(x)          ___bpf_kprobe_args0(), (unsigned long long)PT_REGS_PARM1(ctx)
+#define ___bpf_kprobe_args2(x, args...) ___bpf_kprobe_args1(args), (unsigned long long)PT_REGS_PARM2(ctx)
+#define ___bpf_kprobe_args3(x, args...) ___bpf_kprobe_args2(args), (unsigned long long)PT_REGS_PARM3(ctx)
+#define ___bpf_kprobe_args4(x, args...) ___bpf_kprobe_args3(args), (unsigned long long)PT_REGS_PARM4(ctx)
+#define ___bpf_kprobe_args5(x, args...) ___bpf_kprobe_args4(args), (unsigned long long)PT_REGS_PARM5(ctx)
+#define ___bpf_kprobe_args6(x, args...) ___bpf_kprobe_args5(args), (unsigned long long)PT_REGS_PARM6(ctx)
+#define ___bpf_kprobe_args7(x, args...) ___bpf_kprobe_args6(args), (unsigned long long)PT_REGS_PARM7(ctx)
+#define ___bpf_kprobe_args8(x, args...) ___bpf_kprobe_args7(args), (unsigned long long)PT_REGS_PARM8(ctx)
+#define ___bpf_kprobe_args(args...)     ___bpf_apply(___bpf_kprobe_args, ___bpf_narg(args))(args)
+
+/*
+ * BPF_KPROBE serves the same purpose for kprobes as BPF_PROG for
+ * tp_btf/fentry/fexit BPF programs. It hides the underlying platform-specific
+ * low-level way of getting kprobe input arguments from struct pt_regs, and
+ * provides a familiar typed and named function arguments syntax and
+ * semantics of accessing kprobe input parameters.
+ *
+ * Original struct pt_regs* context is preserved as 'ctx' argument. This might
+ * be necessary when using BPF helpers like bpf_perf_event_output().
+ */
+#define BPF_KPROBE(name, args...)					    \
+name(struct pt_regs *ctx);						    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args);				    \
+typeof(name(0)) name(struct pt_regs *ctx)				    \
+{									    \
+	_Pragma("GCC diagnostic push")					    \
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
+	return ____##name(___bpf_kprobe_args(args));			    \
+	_Pragma("GCC diagnostic pop")					    \
+}									    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args)
+
+#define ___bpf_kretprobe_args0()       ctx
+#define ___bpf_kretprobe_args1(x)      ___bpf_kretprobe_args0(), (unsigned long long)PT_REGS_RC(ctx)
+#define ___bpf_kretprobe_args(args...) ___bpf_apply(___bpf_kretprobe_args, ___bpf_narg(args))(args)
+
+/*
+ * BPF_KRETPROBE is similar to BPF_KPROBE, except, it only provides optional
+ * return value (in addition to `struct pt_regs *ctx`), but no input
+ * arguments, because they will be clobbered by the time probed function
+ * returns.
+ */
+#define BPF_KRETPROBE(name, args...)					    \
+name(struct pt_regs *ctx);						    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args);				    \
+typeof(name(0)) name(struct pt_regs *ctx)				    \
+{									    \
+	_Pragma("GCC diagnostic push")					    \
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
+	return ____##name(___bpf_kretprobe_args(args));			    \
+	_Pragma("GCC diagnostic pop")					    \
+}									    \
+static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args)
+
+/* If kernel has CONFIG_ARCH_HAS_SYSCALL_WRAPPER, read pt_regs directly */
+#define ___bpf_syscall_args0()           ctx
+#define ___bpf_syscall_args1(x)          ___bpf_syscall_args0(), (unsigned long long)PT_REGS_PARM1_SYSCALL(regs)
+#define ___bpf_syscall_args2(x, args...) ___bpf_syscall_args1(args), (unsigned long long)PT_REGS_PARM2_SYSCALL(regs)
+#define ___bpf_syscall_args3(x, args...) ___bpf_syscall_args2(args), (unsigned long long)PT_REGS_PARM3_SYSCALL(regs)
+#define ___bpf_syscall_args4(x, args...) ___bpf_syscall_args3(args), (unsigned long long)PT_REGS_PARM4_SYSCALL(regs)
+#define ___bpf_syscall_args5(x, args...) ___bpf_syscall_args4(args), (unsigned long long)PT_REGS_PARM5_SYSCALL(regs)
+#define ___bpf_syscall_args6(x, args...) ___bpf_syscall_args5(args), (unsigned long long)PT_REGS_PARM6_SYSCALL(regs)
+#define ___bpf_syscall_args7(x, args...) ___bpf_syscall_args6(args), (unsigned long long)PT_REGS_PARM7_SYSCALL(regs)
+#define ___bpf_syscall_args(args...)     ___bpf_apply(___bpf_syscall_args, ___bpf_narg(args))(args)
+
+/* If kernel doesn't have CONFIG_ARCH_HAS_SYSCALL_WRAPPER, we have to BPF_CORE_READ from pt_regs */
+#define ___bpf_syswrap_args0()           ctx
+#define ___bpf_syswrap_args1(x)          ___bpf_syswrap_args0(), (unsigned long long)PT_REGS_PARM1_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args2(x, args...) ___bpf_syswrap_args1(args), (unsigned long long)PT_REGS_PARM2_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args3(x, args...) ___bpf_syswrap_args2(args), (unsigned long long)PT_REGS_PARM3_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args4(x, args...) ___bpf_syswrap_args3(args), (unsigned long long)PT_REGS_PARM4_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args5(x, args...) ___bpf_syswrap_args4(args), (unsigned long long)PT_REGS_PARM5_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args6(x, args...) ___bpf_syswrap_args5(args), (unsigned long long)PT_REGS_PARM6_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args7(x, args...) ___bpf_syswrap_args6(args), (unsigned long long)PT_REGS_PARM7_CORE_SYSCALL(regs)
+#define ___bpf_syswrap_args(args...)     ___bpf_apply(___bpf_syswrap_args, ___bpf_narg(args))(args)
+
+/*
+ * BPF_KSYSCALL is a variant of BPF_KPROBE, which is intended for
+ * tracing syscall functions, like __x64_sys_close. It hides the underlying
+ * platform-specific low-level way of getting syscall input arguments from
+ * struct pt_regs, and provides a familiar typed and named function arguments
+ * syntax and semantics of accessing syscall input parameters.
+ *
+ * Original struct pt_regs * context is preserved as 'ctx' argument. This might
+ * be necessary when using BPF helpers like bpf_perf_event_output().
+ *
+ * At the moment BPF_KSYSCALL does not transparently handle all the calling
+ * convention quirks for the following syscalls:
+ *
+ * - mmap(): __ARCH_WANT_SYS_OLD_MMAP.
+ * - clone(): CONFIG_CLONE_BACKWARDS, CONFIG_CLONE_BACKWARDS2 and
+ *            CONFIG_CLONE_BACKWARDS3.
+ * - socket-related syscalls: __ARCH_WANT_SYS_SOCKETCALL.
+ * - compat syscalls.
+ *
+ * This may or may not change in the future. User needs to take extra measures
+ * to handle such quirks explicitly, if necessary.
+ *
+ * This macro relies on BPF CO-RE support and virtual __kconfig externs.
+ */
+#define BPF_KSYSCALL(name, args...)					    \
+name(struct pt_regs *ctx);						    \
+extern _Bool LINUX_HAS_SYSCALL_WRAPPER __kconfig;			    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args);				    \
+typeof(name(0)) name(struct pt_regs *ctx)				    \
+{									    \
+	struct pt_regs *regs = LINUX_HAS_SYSCALL_WRAPPER		    \
+			       ? (struct pt_regs *)PT_REGS_PARM1(ctx)	    \
+			       : ctx;					    \
+	_Pragma("GCC diagnostic push")					    \
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
+	if (LINUX_HAS_SYSCALL_WRAPPER)					    \
+		return ____##name(___bpf_syswrap_args(args));		    \
+	else								    \
+		return ____##name(___bpf_syscall_args(args));		    \
+	_Pragma("GCC diagnostic pop")					    \
+}									    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args)
+
+#define BPF_KPROBE_SYSCALL BPF_KSYSCALL
+
+/* BPF_UPROBE and BPF_URETPROBE are identical to BPF_KPROBE and BPF_KRETPROBE,
+ * but are named way less confusingly for SEC("uprobe") and SEC("uretprobe")
+ * use cases.
+ */
+#define BPF_UPROBE(name, args...)  BPF_KPROBE(name, ##args)
+#define BPF_URETPROBE(name, args...)  BPF_KRETPROBE(name, ##args)
+
+#endif
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
new file mode 100644
index 000000000..8417de92d
--- /dev/null
+++ b/tools/lib/bpf/btf.c
@@ -0,0 +1,6376 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2018 Facebook */
+
+#include <byteswap.h>
+#include <endian.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/utsname.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/btf.h>
+#include <gelf.h>
+#include "btf.h"
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+#include "hashmap.h"
+#include "strset.h"
+
+#define BTF_MAX_NR_TYPES 0x7fffffffU
+#define BTF_MAX_STR_OFFSET 0x7fffffffU
+
+static struct btf_type btf_void;
+
+/*
+ * Describe how kinds are laid out; some have a singular element following the "struct btf_type",
+ * some have BTF_INFO_VLEN(t->info) elements.  Specify sizes for both.  Flags are currently unused.
+ * Kind layout can be optionally added to the BTF representation in a dedicated section to
+ * facilitate parsing.  New kinds must be added here.
+ */
+static struct btf_layout layouts[NR_BTF_KINDS] = {
+/*				singular element size		vlen element(s) size		flags */
+[BTF_KIND_UNKN] =	{	0,				0,				0 },
+[BTF_KIND_INT] =	{	sizeof(__u32),			0,				0 },
+[BTF_KIND_PTR] =	{	0,				0,				0 },
+[BTF_KIND_ARRAY] =	{	sizeof(struct btf_array),	0,				0 },
+[BTF_KIND_STRUCT] =	{	0,				sizeof(struct btf_member),	0 },
+[BTF_KIND_UNION] =	{	0,				sizeof(struct btf_member),	0 },
+[BTF_KIND_ENUM] =	{	0,				sizeof(struct btf_enum),	0 },
+[BTF_KIND_FWD] =	{	0,				0,				0 },
+[BTF_KIND_TYPEDEF] =	{	0,				0,				0 },
+[BTF_KIND_VOLATILE] =	{	0,				0,				0 },
+[BTF_KIND_CONST] =	{	0,				0,				0 },
+[BTF_KIND_RESTRICT] =	{	0,				0,				0 },
+[BTF_KIND_FUNC] =	{	0,				0,				0 },
+[BTF_KIND_FUNC_PROTO] =	{	0,				sizeof(struct btf_param),	0 },
+[BTF_KIND_VAR] =	{	sizeof(struct btf_var),		0,				0 },
+[BTF_KIND_DATASEC] =	{	0,				sizeof(struct btf_var_secinfo),	0 },
+[BTF_KIND_FLOAT] =	{	0,				0,				0 },
+[BTF_KIND_DECL_TAG] =	{	sizeof(struct btf_decl_tag),	0,				0 },
+[BTF_KIND_TYPE_TAG] =	{	0,				0,				0 },
+[BTF_KIND_ENUM64] =	{	0,				sizeof(struct btf_enum64),	0 },
+};
+
+struct btf {
+	/* raw BTF data in native endianness */
+	void *raw_data;
+	/* raw BTF data in non-native endianness */
+	void *raw_data_swapped;
+	__u32 raw_size;
+	/* whether target endianness differs from the native one */
+	bool swapped_endian;
+
+	/*
+	 * When BTF is loaded from an ELF or raw memory it is stored
+	 * in a contiguous memory block. The type_data, layout and strs_data
+	 * point inside that memory region to their respective parts of BTF
+	 * representation:
+	 *
+	 * +----------------------------------------+---------------+
+	 * |  Header  |  Types  |  Optional layout  |  Strings      |
+	 * +--------------------------------------------------------+
+	 * ^          ^         ^                   ^
+	 * |          |         |                   |
+	 * raw_data   |         |                   |
+	 * types_data-+         |                   |
+	 * layout---------------+                   |
+	 * strs_data--------------------------------+
+	 *
+	 * A separate struct btf_header is embedded as btf->hdr,
+	 * and header information is copied into it.  This allows us
+	 * to handle header data for various header formats; the original,
+	 * the extended header with layout info, etc.
+	 *
+	 * If BTF data is later modified, e.g., due to types added or
+	 * removed, BTF deduplication performed, etc, this contiguous
+	 * representation is broken up into four independent memory
+	 * regions.
+	 *
+	 * raw_data is nulled out at that point, but can be later allocated
+	 * and cached again if user calls btf__raw_data(), at which point
+	 * raw_data will contain a contiguous copy of header, types, optional
+	 * layout and strings.  layout optionally points to a
+	 * btf_layout array - this allows us to encode information about
+	 * the kinds known at encoding time.  If layout is NULL no
+	 * layout information is encoded.
+	 *
+	 * +----------+  +---------+  +-----------+   +-----------+
+	 * |  Header  |  |  Types  |  |  Layout   |   |  Strings  |
+	 * +----------+  +---------+  +-----------+   +-----------+
+	 * ^             ^            ^               ^
+	 * |             |            |               |
+	 * hdr           |            |               |
+	 * types_data----+            |               |
+	 * layout---------------------+               |
+	 * strset__data(strs_set)---------------------+
+	 *
+	 *               +----------+---------+-------------------+-----------+
+	 *               |  Header  |  Types  |  Optional Layout  |  Strings  |
+	 * raw_data----->+----------+---------+-------------------+-----------+
+	 */
+	struct btf_header hdr;
+
+	void *types_data;
+	size_t types_data_cap; /* used size stored in hdr->type_len */
+
+	/* type ID to `struct btf_type *` lookup index
+	 * type_offs[0] corresponds to the first non-VOID type:
+	 *   - for base BTF it's type [1];
+	 *   - for split BTF it's the first non-base BTF type.
+	 */
+	__u32 *type_offs;
+	size_t type_offs_cap;
+	/* number of types in this BTF instance:
+	 *   - doesn't include special [0] void type;
+	 *   - for split BTF counts number of types added on top of base BTF.
+	 */
+	__u32 nr_types;
+	/* the start IDs of named types in sorted BTF */
+	int named_start_id;
+	/* if not NULL, points to the base BTF on top of which the current
+	 * split BTF is based
+	 */
+	struct btf *base_btf;
+	/* BTF type ID of the first type in this BTF instance:
+	 *   - for base BTF it's equal to 1;
+	 *   - for split BTF it's equal to biggest type ID of base BTF plus 1.
+	 */
+	int start_id;
+	/* logical string offset of this BTF instance:
+	 *   - for base BTF it's equal to 0;
+	 *   - for split BTF it's equal to total size of base BTF's string section size.
+	 */
+	int start_str_off;
+
+	/* only one of strs_data or strs_set can be non-NULL, depending on
+	 * whether BTF is in a modifiable state (strs_set is used) or not
+	 * (strs_data points inside raw_data)
+	 */
+	void *strs_data;
+	/* a set of unique strings */
+	struct strset *strs_set;
+	/* whether strings are already deduplicated */
+	bool strs_deduped;
+
+	/* whether base_btf should be freed in btf_free for this instance */
+	bool owns_base;
+
+	/* whether raw_data is a (read-only) mmap */
+	bool raw_data_is_mmap;
+
+	/* is BTF modifiable? i.e. is it split into separate sections as described above? */
+	bool modifiable;
+	/* does BTF have header information we do not support?  If so, disallow
+	 * modification.
+	 */
+	bool has_hdr_extra;
+	/* Points either at raw kind layout data in parsed BTF (if present), or
+	 * at an allocated kind layout array when BTF is modifiable.
+	 */
+	void *layout;
+
+	/* BTF object FD, if loaded into kernel */
+	int fd;
+
+	/* Pointer size (in bytes) for a target architecture of this BTF */
+	int ptr_sz;
+};
+
+static inline __u64 ptr_to_u64(const void *ptr)
+{
+	return (__u64) (unsigned long) ptr;
+}
+
+/* Ensure given dynamically allocated memory region pointed to by *data* with
+ * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough
+ * memory to accommodate *add_cnt* new elements, assuming *cur_cnt* elements
+ * are already used. At most *max_cnt* elements can be ever allocated.
+ * If necessary, memory is reallocated and all existing data is copied over,
+ * new pointer to the memory region is stored at *data, new memory region
+ * capacity (in number of elements) is stored in *cap.
+ * On success, memory pointer to the beginning of unused memory is returned.
+ * On error, NULL is returned.
+ */
+void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
+		     size_t cur_cnt, size_t max_cnt, size_t add_cnt)
+{
+	size_t new_cnt;
+	void *new_data;
+
+	if (cur_cnt + add_cnt <= *cap_cnt)
+		return *data + cur_cnt * elem_sz;
+
+	/* requested more than the set limit */
+	if (cur_cnt + add_cnt > max_cnt)
+		return NULL;
+
+	new_cnt = *cap_cnt;
+	new_cnt += new_cnt / 4;		  /* expand by 25% */
+	if (new_cnt < 16)		  /* but at least 16 elements */
+		new_cnt = 16;
+	if (new_cnt > max_cnt)		  /* but not exceeding a set limit */
+		new_cnt = max_cnt;
+	if (new_cnt < cur_cnt + add_cnt)  /* also ensure we have enough memory */
+		new_cnt = cur_cnt + add_cnt;
+
+	new_data = libbpf_reallocarray(*data, new_cnt, elem_sz);
+	if (!new_data)
+		return NULL;
+
+	/* zero out newly allocated portion of memory */
+	memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz);
+
+	*data = new_data;
+	*cap_cnt = new_cnt;
+	return new_data + cur_cnt * elem_sz;
+}
+
+/* Ensure given dynamically allocated memory region has enough allocated space
+ * to accommodate *need_cnt* elements of size *elem_sz* bytes each
+ */
+int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt)
+{
+	void *p;
+
+	if (need_cnt <= *cap_cnt)
+		return 0;
+
+	p = libbpf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt);
+	if (!p)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void *btf_add_type_offs_mem(struct btf *btf, size_t add_cnt)
+{
+	return libbpf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32),
+			      btf->nr_types, BTF_MAX_NR_TYPES, add_cnt);
+}
+
+static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off)
+{
+	__u32 *p;
+
+	p = btf_add_type_offs_mem(btf, 1);
+	if (!p)
+		return -ENOMEM;
+
+	*p = type_off;
+	return 0;
+}
+
+static void btf_bswap_hdr(struct btf_header *h, __u32 hdr_len)
+{
+	h->magic = bswap_16(h->magic);
+	h->hdr_len = bswap_32(h->hdr_len);
+	h->type_off = bswap_32(h->type_off);
+	h->type_len = bswap_32(h->type_len);
+	h->str_off = bswap_32(h->str_off);
+	h->str_len = bswap_32(h->str_len);
+	/* May be operating on raw data with hdr_len that does not include below fields */
+	if (hdr_len >= sizeof(struct btf_header)) {
+		h->layout_off = bswap_32(h->layout_off);
+		h->layout_len = bswap_32(h->layout_len);
+	}
+}
+
+static int btf_parse_hdr(struct btf *btf)
+{
+	struct btf_header *hdr = btf->raw_data;
+	__u32 hdr_len, meta_left;
+
+	if (btf->raw_size < offsetofend(struct btf_header, str_len)) {
+		pr_debug("BTF header not found\n");
+		return -EINVAL;
+	}
+
+	hdr_len = hdr->hdr_len;
+
+	if (hdr->magic == bswap_16(BTF_MAGIC)) {
+		btf->swapped_endian = true;
+		hdr_len = bswap_32(hdr->hdr_len);
+		if (hdr_len < offsetofend(struct btf_header, str_len)) {
+			pr_warn("Can't load BTF with non-native endianness due to unsupported header length %u\n",
+				hdr_len);
+			return -ENOTSUP;
+		}
+	} else if (hdr->magic != BTF_MAGIC) {
+		pr_debug("Invalid BTF magic: %x\n", hdr->magic);
+		return -EINVAL;
+	}
+
+	if (btf->raw_size < hdr_len) {
+		pr_debug("BTF header len %u larger than data size %u\n",
+			 hdr_len, btf->raw_size);
+		return -EINVAL;
+	}
+
+	if (btf->swapped_endian)
+		btf_bswap_hdr(hdr, hdr_len);
+
+	memcpy(&btf->hdr, hdr, min((size_t)hdr_len, sizeof(struct btf_header)));
+
+	/* If unknown header data is found, modification is prohibited in
+	 * btf_ensure_modifiable().
+	 */
+	if (hdr_len > sizeof(struct btf_header)) {
+		__u8 *h = (__u8 *)hdr;
+		__u32 i;
+
+		for (i = sizeof(struct btf_header); i < hdr_len; i++) {
+			if (!h[i])
+				continue;
+			btf->has_hdr_extra = true;
+			pr_debug("Unknown BTF header data at offset %u; modification is disallowed\n",
+				 i);
+			break;
+		}
+	}
+
+	meta_left = btf->raw_size - hdr_len;
+	if (meta_left < (long long)btf->hdr.str_off + btf->hdr.str_len) {
+		pr_debug("Invalid BTF total size: %u\n", btf->raw_size);
+		return -EINVAL;
+	}
+
+	if ((long long)btf->hdr.type_off + btf->hdr.type_len > btf->hdr.str_off) {
+		pr_debug("Invalid BTF data sections layout: type data at %u + %u, strings data at %u + %u\n",
+			 btf->hdr.type_off, btf->hdr.type_len, btf->hdr.str_off,
+			 btf->hdr.str_len);
+		return -EINVAL;
+	}
+
+	if (btf->hdr.type_off % 4) {
+		pr_debug("BTF type section is not aligned to 4 bytes\n");
+		return -EINVAL;
+	}
+
+	if (btf->hdr.layout_len == 0)
+		return 0;
+
+	/* optional layout section sits between types and strings */
+	if (btf->hdr.layout_off % 4) {
+		pr_debug("BTF layout section is not aligned to 4 bytes\n");
+		return -EINVAL;
+	}
+	if (btf->hdr.layout_off < (long long)btf->hdr.type_off + btf->hdr.type_len) {
+		pr_debug("Invalid BTF data sections layout: type data at %u + %u,  layout data at %u + %u\n",
+			 btf->hdr.type_off, btf->hdr.type_len,
+			 btf->hdr.layout_off, btf->hdr.layout_len);
+		return -EINVAL;
+	}
+	if ((long long)btf->hdr.layout_off + btf->hdr.layout_len > btf->hdr.str_off ||
+	    btf->hdr.layout_off > btf->hdr.str_off) {
+		pr_debug("Invalid BTF data sections layout: layout data at %u + %u, strings data at %u\n",
+			 btf->hdr.layout_off, btf->hdr.layout_len, btf->hdr.str_off);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int btf_parse_str_sec(struct btf *btf)
+{
+	const char *start = btf->strs_data;
+	const char *end = start + btf->hdr.str_len;
+
+	if (btf->base_btf && btf->hdr.str_len == 0)
+		return 0;
+	if (!btf->hdr.str_len || btf->hdr.str_len - 1 > BTF_MAX_STR_OFFSET || end[-1]) {
+		pr_debug("Invalid BTF string section\n");
+		return -EINVAL;
+	}
+	if (!btf->base_btf && start[0]) {
+		pr_debug("Malformed BTF string section, did you forget to provide base BTF?\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int btf_parse_layout_sec(struct btf *btf)
+{
+	if (!btf->hdr.layout_len)
+		return 0;
+
+	if (btf->hdr.layout_len % sizeof(struct btf_layout) != 0) {
+		pr_debug("Invalid BTF kind layout section\n");
+		return -EINVAL;
+	}
+	btf->layout = btf->raw_data + btf->hdr.hdr_len + btf->hdr.layout_off;
+
+	if (btf->swapped_endian) {
+		struct btf_layout *l, *end = btf->layout + btf->hdr.layout_len;
+
+		for (l = btf->layout; l < end; l++)
+			l->flags = bswap_16(l->flags);
+	}
+
+	return 0;
+}
+
+/* for unknown kinds, consult kind layout. */
+static int btf_type_size_unknown(const struct btf *btf, const struct btf_type *t)
+{
+	__u32 l_cnt = btf->hdr.layout_len / sizeof(struct btf_layout);
+	struct btf_layout *l = btf->layout;
+	__u32 vlen = btf_vlen(t);
+	__u32 kind = btf_kind(t);
+
+	/* Fall back to base BTF if needed as they share layout information */
+	if (!l) {
+		struct btf *base_btf = btf->base_btf;
+
+		if (base_btf) {
+			l = base_btf->layout;
+			l_cnt = base_btf->hdr.layout_len / sizeof(struct btf_layout);
+		}
+	}
+	if (!l || kind >= l_cnt) {
+		pr_debug("Unsupported BTF_KIND: %u\n", btf_kind(t));
+		return -EINVAL;
+	}
+	if (l[kind].info_sz % 4) {
+		pr_debug("Unsupported info_sz %u for kind %u\n",
+			  l[kind].info_sz, kind);
+		return -EINVAL;
+	}
+	if (l[kind].elem_sz % 4) {
+		pr_debug("Unsupported elem_sz %u for kind %u\n",
+			 l[kind].elem_sz, kind);
+		return -EINVAL;
+	}
+
+	return sizeof(struct btf_type) + l[kind].info_sz + vlen * l[kind].elem_sz;
+}
+
+static int btf_type_size(const struct btf *btf, const struct btf_type *t)
+{
+	const int base_size = sizeof(struct btf_type);
+	__u32 vlen = btf_vlen(t);
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_FWD:
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_FLOAT:
+	case BTF_KIND_TYPE_TAG:
+		return base_size;
+	case BTF_KIND_INT:
+		return base_size + sizeof(__u32);
+	case BTF_KIND_ENUM:
+		return base_size + vlen * sizeof(struct btf_enum);
+	case BTF_KIND_ENUM64:
+		return base_size + vlen * sizeof(struct btf_enum64);
+	case BTF_KIND_ARRAY:
+		return base_size + sizeof(struct btf_array);
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+		return base_size + vlen * sizeof(struct btf_member);
+	case BTF_KIND_FUNC_PROTO:
+		return base_size + vlen * sizeof(struct btf_param);
+	case BTF_KIND_VAR:
+		return base_size + sizeof(struct btf_var);
+	case BTF_KIND_DATASEC:
+		return base_size + vlen * sizeof(struct btf_var_secinfo);
+	case BTF_KIND_DECL_TAG:
+		return base_size + sizeof(struct btf_decl_tag);
+	default:
+		return btf_type_size_unknown(btf, t);
+	}
+}
+
+static void btf_bswap_type_base(struct btf_type *t)
+{
+	t->name_off = bswap_32(t->name_off);
+	t->info = bswap_32(t->info);
+	t->type = bswap_32(t->type);
+}
+
+static int btf_bswap_type_rest(struct btf_type *t)
+{
+	struct btf_var_secinfo *v;
+	struct btf_enum64 *e64;
+	struct btf_member *m;
+	struct btf_array *a;
+	struct btf_param *p;
+	struct btf_enum *e;
+	__u32 vlen = btf_vlen(t);
+	int i;
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_FWD:
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_FLOAT:
+	case BTF_KIND_TYPE_TAG:
+		return 0;
+	case BTF_KIND_INT:
+		*(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1));
+		return 0;
+	case BTF_KIND_ENUM:
+		for (i = 0, e = btf_enum(t); i < vlen; i++, e++) {
+			e->name_off = bswap_32(e->name_off);
+			e->val = bswap_32(e->val);
+		}
+		return 0;
+	case BTF_KIND_ENUM64:
+		for (i = 0, e64 = btf_enum64(t); i < vlen; i++, e64++) {
+			e64->name_off = bswap_32(e64->name_off);
+			e64->val_lo32 = bswap_32(e64->val_lo32);
+			e64->val_hi32 = bswap_32(e64->val_hi32);
+		}
+		return 0;
+	case BTF_KIND_ARRAY:
+		a = btf_array(t);
+		a->type = bswap_32(a->type);
+		a->index_type = bswap_32(a->index_type);
+		a->nelems = bswap_32(a->nelems);
+		return 0;
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+		for (i = 0, m = btf_members(t); i < vlen; i++, m++) {
+			m->name_off = bswap_32(m->name_off);
+			m->type = bswap_32(m->type);
+			m->offset = bswap_32(m->offset);
+		}
+		return 0;
+	case BTF_KIND_FUNC_PROTO:
+		for (i = 0, p = btf_params(t); i < vlen; i++, p++) {
+			p->name_off = bswap_32(p->name_off);
+			p->type = bswap_32(p->type);
+		}
+		return 0;
+	case BTF_KIND_VAR:
+		btf_var(t)->linkage = bswap_32(btf_var(t)->linkage);
+		return 0;
+	case BTF_KIND_DATASEC:
+		for (i = 0, v = btf_var_secinfos(t); i < vlen; i++, v++) {
+			v->type = bswap_32(v->type);
+			v->offset = bswap_32(v->offset);
+			v->size = bswap_32(v->size);
+		}
+		return 0;
+	case BTF_KIND_DECL_TAG:
+		btf_decl_tag(t)->component_idx = bswap_32(btf_decl_tag(t)->component_idx);
+		return 0;
+	default:
+		pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
+		return -EINVAL;
+	}
+}
+
+static int btf_parse_type_sec(struct btf *btf)
+{
+	void *next_type = btf->types_data;
+	void *end_type = next_type + btf->hdr.type_len;
+	int err, type_size;
+
+	while (next_type + sizeof(struct btf_type) <= end_type) {
+		if (btf->swapped_endian)
+			btf_bswap_type_base(next_type);
+
+		type_size = btf_type_size(btf, next_type);
+		if (type_size < 0)
+			return type_size;
+		if (next_type + type_size > end_type) {
+			pr_warn("BTF type [%u] is malformed\n", btf->start_id + btf->nr_types);
+			return -EINVAL;
+		}
+
+		if (btf->swapped_endian && btf_bswap_type_rest(next_type))
+			return -EINVAL;
+
+		err = btf_add_type_idx_entry(btf, next_type - btf->types_data);
+		if (err)
+			return err;
+
+		next_type += type_size;
+		btf->nr_types++;
+	}
+
+	if (next_type != end_type) {
+		pr_warn("BTF types data is malformed\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_validate_str(const struct btf *btf, __u32 str_off, const char *what, __u32 type_id)
+{
+	const char *s;
+
+	s = btf__str_by_offset(btf, str_off);
+	if (!s) {
+		pr_warn("btf: type [%u]: invalid %s (string offset %u)\n", type_id, what, str_off);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_validate_id(const struct btf *btf, __u32 id, __u32 ctx_id)
+{
+	const struct btf_type *t;
+
+	t = btf__type_by_id(btf, id);
+	if (!t) {
+		pr_warn("btf: type [%u]: invalid referenced type ID %u\n", ctx_id, id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_validate_type(const struct btf *btf, const struct btf_type *t, __u32 id)
+{
+	__u32 kind = btf_kind(t);
+	int err, i, n;
+
+	err = btf_validate_str(btf, t->name_off, "type name", id);
+	if (err)
+		return err;
+
+	switch (kind) {
+	case BTF_KIND_UNKN:
+	case BTF_KIND_INT:
+	case BTF_KIND_FWD:
+	case BTF_KIND_FLOAT:
+		break;
+	case BTF_KIND_PTR:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_VAR:
+	case BTF_KIND_DECL_TAG:
+	case BTF_KIND_TYPE_TAG:
+		err = btf_validate_id(btf, t->type, id);
+		if (err)
+			return err;
+		break;
+	case BTF_KIND_ARRAY: {
+		const struct btf_array *a = btf_array(t);
+
+		err = btf_validate_id(btf, a->type, id);
+		err = err ?: btf_validate_id(btf, a->index_type, id);
+		if (err)
+			return err;
+		break;
+	}
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m = btf_members(t);
+
+		n = btf_vlen(t);
+		for (i = 0; i < n; i++, m++) {
+			err = btf_validate_str(btf, m->name_off, "field name", id);
+			err = err ?: btf_validate_id(btf, m->type, id);
+			if (err)
+				return err;
+		}
+		break;
+	}
+	case BTF_KIND_ENUM: {
+		const struct btf_enum *m = btf_enum(t);
+
+		n = btf_vlen(t);
+		for (i = 0; i < n; i++, m++) {
+			err = btf_validate_str(btf, m->name_off, "enum name", id);
+			if (err)
+				return err;
+		}
+		break;
+	}
+	case BTF_KIND_ENUM64: {
+		const struct btf_enum64 *m = btf_enum64(t);
+
+		n = btf_vlen(t);
+		for (i = 0; i < n; i++, m++) {
+			err = btf_validate_str(btf, m->name_off, "enum name", id);
+			if (err)
+				return err;
+		}
+		break;
+	}
+	case BTF_KIND_FUNC: {
+		const struct btf_type *ft;
+
+		err = btf_validate_id(btf, t->type, id);
+		if (err)
+			return err;
+		ft = btf__type_by_id(btf, t->type);
+		if (btf_kind(ft) != BTF_KIND_FUNC_PROTO) {
+			pr_warn("btf: type [%u]: referenced type [%u] is not FUNC_PROTO\n", id, t->type);
+			return -EINVAL;
+		}
+		break;
+	}
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *m = btf_params(t);
+
+		n = btf_vlen(t);
+		for (i = 0; i < n; i++, m++) {
+			err = btf_validate_str(btf, m->name_off, "param name", id);
+			err = err ?: btf_validate_id(btf, m->type, id);
+			if (err)
+				return err;
+		}
+		break;
+	}
+	case BTF_KIND_DATASEC: {
+		const struct btf_var_secinfo *m = btf_var_secinfos(t);
+
+		n = btf_vlen(t);
+		for (i = 0; i < n; i++, m++) {
+			err = btf_validate_id(btf, m->type, id);
+			if (err)
+				return err;
+		}
+		break;
+	}
+	default:
+		/* Kind may be represented in kind layout information. */
+		if (btf_type_size_unknown(btf, t) < 0) {
+			pr_warn("btf: type [%u]: unrecognized kind %u\n", id, kind);
+			return -EINVAL;
+		}
+		break;
+	}
+	return 0;
+}
+
+/* Validate basic sanity of BTF. It's intentionally less thorough than
+ * kernel's validation and validates only properties of BTF that libbpf relies
+ * on to be correct (e.g., valid type IDs, valid string offsets, etc)
+ */
+static int btf_sanity_check(const struct btf *btf)
+{
+	const struct btf_type *t;
+	__u32 i, n = btf__type_cnt(btf);
+	int err;
+
+	for (i = btf->start_id; i < n; i++) {
+		t = btf_type_by_id(btf, i);
+		err = btf_validate_type(btf, t, i);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+__u32 btf__type_cnt(const struct btf *btf)
+{
+	return btf->start_id + btf->nr_types;
+}
+
+const struct btf *btf__base_btf(const struct btf *btf)
+{
+	return btf->base_btf;
+}
+
+/* internal helper returning non-const pointer to a type */
+struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id)
+{
+	if (type_id == 0)
+		return &btf_void;
+	if (type_id < btf->start_id)
+		return btf_type_by_id(btf->base_btf, type_id);
+	return btf->types_data + btf->type_offs[type_id - btf->start_id];
+}
+
+const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
+{
+	if (type_id >= btf->start_id + btf->nr_types)
+		return errno = EINVAL, NULL;
+	return btf_type_by_id((struct btf *)btf, type_id);
+}
+
+static int determine_ptr_size(const struct btf *btf)
+{
+	static const char * const long_aliases[] = {
+		"long",
+		"long int",
+		"int long",
+		"unsigned long",
+		"long unsigned",
+		"unsigned long int",
+		"unsigned int long",
+		"long unsigned int",
+		"long int unsigned",
+		"int unsigned long",
+		"int long unsigned",
+	};
+	const struct btf_type *t;
+	const char *name;
+	int i, j, n;
+
+	if (btf->base_btf && btf->base_btf->ptr_sz > 0)
+		return btf->base_btf->ptr_sz;
+
+	n = btf__type_cnt(btf);
+	for (i = 1; i < n; i++) {
+		t = btf__type_by_id(btf, i);
+		if (!btf_is_int(t))
+			continue;
+
+		if (t->size != 4 && t->size != 8)
+			continue;
+
+		name = btf__name_by_offset(btf, t->name_off);
+		if (!name)
+			continue;
+
+		for (j = 0; j < ARRAY_SIZE(long_aliases); j++) {
+			if (strcmp(name, long_aliases[j]) == 0)
+				return t->size;
+		}
+	}
+
+	return -1;
+}
+
+static size_t btf_ptr_sz(const struct btf *btf)
+{
+	if (!btf->ptr_sz)
+		((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
+	return btf->ptr_sz < 0 ? sizeof(void *) : btf->ptr_sz;
+}
+
+/* Return pointer size this BTF instance assumes. The size is heuristically
+ * determined by looking for 'long' or 'unsigned long' integer type and
+ * recording its size in bytes. If BTF type information doesn't have any such
+ * type, this function returns 0. In the latter case, native architecture's
+ * pointer size is assumed, so will be either 4 or 8, depending on
+ * architecture that libbpf was compiled for. It's possible to override
+ * guessed value by using btf__set_pointer_size() API.
+ */
+size_t btf__pointer_size(const struct btf *btf)
+{
+	if (!btf->ptr_sz)
+		((struct btf *)btf)->ptr_sz = determine_ptr_size(btf);
+
+	if (btf->ptr_sz < 0)
+		/* not enough BTF type info to guess */
+		return 0;
+
+	return btf->ptr_sz;
+}
+
+/* Override or set pointer size in bytes. Only values of 4 and 8 are
+ * supported.
+ */
+int btf__set_pointer_size(struct btf *btf, size_t ptr_sz)
+{
+	if (ptr_sz != 4 && ptr_sz != 8)
+		return libbpf_err(-EINVAL);
+	btf->ptr_sz = ptr_sz;
+	return 0;
+}
+
+static bool is_host_big_endian(void)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	return false;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	return true;
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+}
+
+enum btf_endianness btf__endianness(const struct btf *btf)
+{
+	if (is_host_big_endian())
+		return btf->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN;
+	else
+		return btf->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
+}
+
+int btf__set_endianness(struct btf *btf, enum btf_endianness endian)
+{
+	if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN)
+		return libbpf_err(-EINVAL);
+
+	btf->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN);
+	if (!btf->swapped_endian) {
+		free(btf->raw_data_swapped);
+		btf->raw_data_swapped = NULL;
+	}
+	return 0;
+}
+
+static bool btf_type_is_void(const struct btf_type *t)
+{
+	return t == &btf_void || btf_is_fwd(t);
+}
+
+static bool btf_type_is_void_or_null(const struct btf_type *t)
+{
+	return !t || btf_type_is_void(t);
+}
+
+#define MAX_RESOLVE_DEPTH 32
+
+__s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
+{
+	const struct btf_array *array;
+	const struct btf_type *t;
+	__u32 nelems = 1;
+	__s64 size = -1;
+	int i;
+
+	t = btf__type_by_id(btf, type_id);
+	for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t); i++) {
+		switch (btf_kind(t)) {
+		case BTF_KIND_INT:
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+		case BTF_KIND_DATASEC:
+		case BTF_KIND_FLOAT:
+			size = t->size;
+			goto done;
+		case BTF_KIND_PTR:
+			size = btf_ptr_sz(btf);
+			goto done;
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_VAR:
+		case BTF_KIND_DECL_TAG:
+		case BTF_KIND_TYPE_TAG:
+			type_id = t->type;
+			break;
+		case BTF_KIND_ARRAY:
+			array = btf_array(t);
+			if (nelems && array->nelems > UINT32_MAX / nelems)
+				return libbpf_err(-E2BIG);
+			nelems *= array->nelems;
+			type_id = array->type;
+			break;
+		default:
+			return libbpf_err(-EINVAL);
+		}
+
+		t = btf__type_by_id(btf, type_id);
+	}
+
+done:
+	if (size < 0)
+		return libbpf_err(-EINVAL);
+	if (nelems && size > UINT32_MAX / nelems)
+		return libbpf_err(-E2BIG);
+
+	return nelems * size;
+}
+
+int btf__align_of(const struct btf *btf, __u32 id)
+{
+	const struct btf_type *t = btf__type_by_id(btf, id);
+	__u16 kind = btf_kind(t);
+
+	switch (kind) {
+	case BTF_KIND_INT:
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+	case BTF_KIND_FLOAT:
+		return min(btf_ptr_sz(btf), (size_t)t->size);
+	case BTF_KIND_PTR:
+		return btf_ptr_sz(btf);
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_TYPE_TAG:
+		return btf__align_of(btf, t->type);
+	case BTF_KIND_ARRAY:
+		return btf__align_of(btf, btf_array(t)->type);
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m = btf_members(t);
+		__u32 vlen = btf_vlen(t);
+		int i, max_align = 1, align;
+
+		for (i = 0; i < vlen; i++, m++) {
+			align = btf__align_of(btf, m->type);
+			if (align <= 0)
+				return libbpf_err(align);
+			max_align = max(max_align, align);
+
+			/* if field offset isn't aligned according to field
+			 * type's alignment, then struct must be packed
+			 */
+			if (btf_member_bitfield_size(t, i) == 0 &&
+			    (m->offset % (8 * align)) != 0)
+				return 1;
+		}
+
+		/* if struct/union size isn't a multiple of its alignment,
+		 * then struct must be packed
+		 */
+		if ((t->size % max_align) != 0)
+			return 1;
+
+		return max_align;
+	}
+	default:
+		pr_warn("unsupported BTF_KIND:%u\n", btf_kind(t));
+		return errno = EINVAL, 0;
+	}
+}
+
+int btf__resolve_type(const struct btf *btf, __u32 type_id)
+{
+	const struct btf_type *t;
+	int depth = 0;
+
+	t = btf__type_by_id(btf, type_id);
+	while (depth < MAX_RESOLVE_DEPTH &&
+	       !btf_type_is_void_or_null(t) &&
+	       (btf_is_mod(t) || btf_is_typedef(t) || btf_is_var(t))) {
+		type_id = t->type;
+		t = btf__type_by_id(btf, type_id);
+		depth++;
+	}
+
+	if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
+		return libbpf_err(-EINVAL);
+
+	return type_id;
+}
+
+static void btf_check_sorted(struct btf *btf)
+{
+	__u32 i, n, named_start_id = 0;
+
+	n = btf__type_cnt(btf);
+	for (i = btf->start_id + 1; i < n; i++) {
+		struct btf_type *ta = btf_type_by_id(btf, i - 1);
+		struct btf_type *tb = btf_type_by_id(btf, i);
+		const char *na = btf__str_by_offset(btf, ta->name_off);
+		const char *nb = btf__str_by_offset(btf, tb->name_off);
+
+		if (strcmp(na, nb) > 0)
+			return;
+
+		if (named_start_id == 0 && na[0] != '\0')
+			named_start_id = i - 1;
+		if (named_start_id == 0 && nb[0] != '\0')
+			named_start_id = i;
+	}
+
+	if (named_start_id)
+		btf->named_start_id = named_start_id;
+}
+
+static __s32 btf_find_type_by_name_bsearch(const struct btf *btf, const char *name,
+					   __s32 start_id)
+{
+	const struct btf_type *t;
+	const char *tname;
+	__s32 l, r, m;
+
+	l = start_id;
+	r = btf__type_cnt(btf) - 1;
+	while (l <= r) {
+		m = l + (r - l) / 2;
+		t = btf_type_by_id(btf, m);
+		tname = btf__str_by_offset(btf, t->name_off);
+		if (strcmp(tname, name) >= 0) {
+			if (l == r)
+				return r;
+			r = m;
+		} else {
+			l = m + 1;
+		}
+	}
+
+	return btf__type_cnt(btf);
+}
+
+static __s32 btf_find_by_name_kind(const struct btf *btf, int start_id,
+				   const char *type_name, __s32 kind)
+{
+	__u32 nr_types = btf__type_cnt(btf);
+	const struct btf_type *t;
+	const char *tname;
+	__s32 id;
+
+	if (start_id < btf->start_id) {
+		id = btf_find_by_name_kind(btf->base_btf, start_id,
+					   type_name, kind);
+		if (id >= 0)
+			return id;
+		start_id = btf->start_id;
+	}
+
+	if (kind == BTF_KIND_UNKN || strcmp(type_name, "void") == 0)
+		return 0;
+
+	if (btf->named_start_id > 0 && type_name[0]) {
+		start_id = max(start_id, btf->named_start_id);
+		id = btf_find_type_by_name_bsearch(btf, type_name, start_id);
+		for (; id < nr_types; id++) {
+			t = btf__type_by_id(btf, id);
+			tname = btf__str_by_offset(btf, t->name_off);
+			if (strcmp(tname, type_name) != 0)
+				return libbpf_err(-ENOENT);
+			if (kind < 0 || btf_kind(t) == kind)
+				return id;
+		}
+	} else {
+		for (id = start_id; id < nr_types; id++) {
+			t = btf_type_by_id(btf, id);
+			if (kind > 0 && btf_kind(t) != kind)
+				continue;
+			tname = btf__str_by_offset(btf, t->name_off);
+			if (strcmp(tname, type_name) == 0)
+				return id;
+		}
+	}
+
+	return libbpf_err(-ENOENT);
+}
+
+/* the kind value of -1 indicates that kind matching should be skipped */
+__s32 btf__find_by_name(const struct btf *btf, const char *type_name)
+{
+	return btf_find_by_name_kind(btf, 1, type_name, -1);
+}
+
+__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
+				 __u32 kind)
+{
+	return btf_find_by_name_kind(btf, btf->start_id, type_name, kind);
+}
+
+__s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
+			     __u32 kind)
+{
+	return btf_find_by_name_kind(btf, 1, type_name, kind);
+}
+
+static bool btf_is_modifiable(const struct btf *btf)
+{
+	/* BTF is modifiable if split into multiple sections */
+	return btf->modifiable;
+}
+
+static void btf_free_raw_data(struct btf *btf)
+{
+	if (btf->raw_data_is_mmap) {
+		munmap(btf->raw_data, btf->raw_size);
+		btf->raw_data_is_mmap = false;
+	} else {
+		free(btf->raw_data);
+	}
+	btf->raw_data = NULL;
+}
+
+void btf__free(struct btf *btf)
+{
+	if (IS_ERR_OR_NULL(btf))
+		return;
+
+	if (btf->fd >= 0)
+		close(btf->fd);
+
+	if (btf_is_modifiable(btf)) {
+		/* if BTF was modified after loading, it will have a split
+		 * in-memory representation for types, strings and layout
+		 * sections, so we need to free all of them individually. It
+		 * might still have a cached contiguous raw data present,
+		 * which will be unconditionally freed below.
+		 */
+		free(btf->types_data);
+		strset__free(btf->strs_set);
+		free(btf->layout);
+	}
+	btf_free_raw_data(btf);
+	free(btf->raw_data_swapped);
+	free(btf->type_offs);
+	if (btf->owns_base)
+		btf__free(btf->base_btf);
+	free(btf);
+}
+
+static struct btf *btf_new_empty(struct btf_new_opts *opts)
+{
+	bool add_layout = OPTS_GET(opts, add_layout, false);
+	struct btf *base_btf = OPTS_GET(opts, base_btf, NULL);
+	struct btf_header *hdr;
+	struct btf *btf;
+
+	btf = calloc(1, sizeof(*btf));
+	if (!btf)
+		return ERR_PTR(-ENOMEM);
+
+	btf->nr_types = 0;
+	btf->start_id = 1;
+	btf->start_str_off = 0;
+	btf->fd = -1;
+	btf->ptr_sz = sizeof(void *);
+	btf->swapped_endian = false;
+	btf->named_start_id = 0;
+
+	if (base_btf) {
+		btf->base_btf = base_btf;
+		btf->start_id = btf__type_cnt(base_btf);
+		btf->start_str_off = base_btf->hdr.str_len + base_btf->start_str_off;
+		btf->swapped_endian = base_btf->swapped_endian;
+	}
+
+	/* +1 for empty string at offset 0 */
+	btf->raw_size = sizeof(struct btf_header) + (base_btf ? 0 : 1);
+	if (add_layout)
+		btf->raw_size += sizeof(layouts);
+	btf->raw_data = calloc(1, btf->raw_size);
+	if (!btf->raw_data) {
+		free(btf);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	hdr = btf->raw_data;
+	hdr->hdr_len = sizeof(struct btf_header);
+	hdr->magic = BTF_MAGIC;
+	hdr->version = BTF_VERSION;
+
+	btf->types_data = btf->raw_data + hdr->hdr_len;
+	btf->strs_data = btf->raw_data + hdr->hdr_len;
+	hdr->str_len = base_btf ? 0 : 1; /* empty string at offset 0 */
+
+	if (add_layout) {
+		hdr->layout_len = sizeof(layouts);
+		btf->layout = layouts;
+		/*
+		 * No need to swap endianness here as btf_get_raw_data()
+		 * will do this for us if btf->swapped_endian is true.
+		 */
+		memcpy(btf->raw_data + hdr->hdr_len, layouts, sizeof(layouts));
+		btf->strs_data += sizeof(layouts);
+		hdr->str_off += sizeof(layouts);
+	}
+
+	memcpy(&btf->hdr, hdr, sizeof(*hdr));
+
+	return btf;
+}
+
+struct btf *btf__new_empty(void)
+{
+	return libbpf_ptr(btf_new_empty(NULL));
+}
+
+struct btf *btf__new_empty_split(struct btf *base_btf)
+{
+	LIBBPF_OPTS(btf_new_opts, opts);
+
+	opts.base_btf = base_btf;
+
+	return libbpf_ptr(btf_new_empty(&opts));
+}
+
+struct btf *btf__new_empty_opts(struct btf_new_opts *opts)
+{
+	if (!OPTS_VALID(opts, btf_new_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	return libbpf_ptr(btf_new_empty(opts));
+}
+
+static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf, bool is_mmap)
+{
+	struct btf *btf;
+	int err;
+
+	btf = calloc(1, sizeof(struct btf));
+	if (!btf)
+		return ERR_PTR(-ENOMEM);
+
+	btf->nr_types = 0;
+	btf->start_id = 1;
+	btf->start_str_off = 0;
+	btf->fd = -1;
+	btf->named_start_id = 0;
+
+	if (base_btf) {
+		btf->base_btf = base_btf;
+		btf->start_id = btf__type_cnt(base_btf);
+		btf->start_str_off = base_btf->hdr.str_len + base_btf->start_str_off;
+	}
+
+	if (is_mmap) {
+		btf->raw_data = (void *)data;
+		btf->raw_data_is_mmap = true;
+	} else {
+		btf->raw_data = malloc(size);
+		if (!btf->raw_data) {
+			err = -ENOMEM;
+			goto done;
+		}
+		memcpy(btf->raw_data, data, size);
+	}
+
+	btf->raw_size = size;
+
+	err = btf_parse_hdr(btf);
+	if (err)
+		goto done;
+
+	btf->strs_data = btf->raw_data + btf->hdr.hdr_len + btf->hdr.str_off;
+	btf->types_data = btf->raw_data + btf->hdr.hdr_len + btf->hdr.type_off;
+
+	err = btf_parse_str_sec(btf);
+	err = err ?: btf_parse_layout_sec(btf);
+	err = err ?: btf_parse_type_sec(btf);
+	err = err ?: btf_sanity_check(btf);
+	if (err)
+		goto done;
+	btf_check_sorted(btf);
+
+done:
+	if (err) {
+		btf__free(btf);
+		return ERR_PTR(err);
+	}
+
+	return btf;
+}
+
+struct btf *btf__new(const void *data, __u32 size)
+{
+	return libbpf_ptr(btf_new(data, size, NULL, false));
+}
+
+struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf)
+{
+	return libbpf_ptr(btf_new(data, size, base_btf, false));
+}
+
+struct btf_elf_secs {
+	Elf_Data *btf_data;
+	Elf_Data *btf_ext_data;
+	Elf_Data *btf_base_data;
+};
+
+static int btf_find_elf_sections(Elf *elf, const char *path, struct btf_elf_secs *secs)
+{
+	Elf_Scn *scn = NULL;
+	Elf_Data *data;
+	GElf_Ehdr ehdr;
+	size_t shstrndx;
+	int idx = 0;
+
+	if (!gelf_getehdr(elf, &ehdr)) {
+		pr_warn("failed to get EHDR from %s\n", path);
+		goto err;
+	}
+
+	if (elf_getshdrstrndx(elf, &shstrndx)) {
+		pr_warn("failed to get section names section index for %s\n",
+			path);
+		goto err;
+	}
+
+	if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) {
+		pr_warn("failed to get e_shstrndx from %s\n", path);
+		goto err;
+	}
+
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		Elf_Data **field;
+		GElf_Shdr sh;
+		char *name;
+
+		idx++;
+		if (gelf_getshdr(scn, &sh) != &sh) {
+			pr_warn("failed to get section(%d) header from %s\n",
+				idx, path);
+			goto err;
+		}
+		name = elf_strptr(elf, shstrndx, sh.sh_name);
+		if (!name) {
+			pr_warn("failed to get section(%d) name from %s\n",
+				idx, path);
+			goto err;
+		}
+
+		if (strcmp(name, BTF_ELF_SEC) == 0)
+			field = &secs->btf_data;
+		else if (strcmp(name, BTF_EXT_ELF_SEC) == 0)
+			field = &secs->btf_ext_data;
+		else if (strcmp(name, BTF_BASE_ELF_SEC) == 0)
+			field = &secs->btf_base_data;
+		else
+			continue;
+
+		if (sh.sh_type != SHT_PROGBITS) {
+			pr_warn("unexpected section type (%u) of section(%d, %s) from %s\n",
+				sh.sh_type, idx, name, path);
+			goto err;
+		}
+
+		data = elf_getdata(scn, 0);
+		if (!data) {
+			pr_warn("failed to get section(%d, %s) data from %s\n",
+				idx, name, path);
+			goto err;
+		}
+		*field = data;
+	}
+
+	return 0;
+
+err:
+	return -LIBBPF_ERRNO__FORMAT;
+}
+
+static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
+				 struct btf_ext **btf_ext)
+{
+	struct btf_elf_secs secs = {};
+	struct btf *dist_base_btf = NULL;
+	struct btf *btf = NULL;
+	int err = 0, fd = -1;
+	Elf *elf = NULL;
+
+	if (elf_version(EV_CURRENT) == EV_NONE) {
+		pr_warn("failed to init libelf for %s\n", path);
+		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
+	}
+
+	fd = open(path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		err = -errno;
+		pr_warn("failed to open %s: %s\n", path, errstr(err));
+		return ERR_PTR(err);
+	}
+
+	elf = elf_begin(fd, ELF_C_READ, NULL);
+	if (!elf) {
+		err = -LIBBPF_ERRNO__FORMAT;
+		pr_warn("failed to open %s as ELF file\n", path);
+		goto done;
+	}
+
+	err = btf_find_elf_sections(elf, path, &secs);
+	if (err)
+		goto done;
+
+	if (!secs.btf_data) {
+		pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path);
+		err = -ENODATA;
+		goto done;
+	}
+
+	if (secs.btf_base_data) {
+		dist_base_btf = btf_new(secs.btf_base_data->d_buf, secs.btf_base_data->d_size,
+					NULL, false);
+		if (IS_ERR(dist_base_btf)) {
+			err = PTR_ERR(dist_base_btf);
+			dist_base_btf = NULL;
+			goto done;
+		}
+	}
+
+	btf = btf_new(secs.btf_data->d_buf, secs.btf_data->d_size,
+		      dist_base_btf ?: base_btf, false);
+	if (IS_ERR(btf)) {
+		err = PTR_ERR(btf);
+		goto done;
+	}
+	if (dist_base_btf && base_btf) {
+		err = btf__relocate(btf, base_btf);
+		if (err)
+			goto done;
+		btf__free(dist_base_btf);
+		dist_base_btf = NULL;
+	}
+
+	switch (gelf_getclass(elf)) {
+	case ELFCLASS32:
+		btf__set_pointer_size(btf, 4);
+		break;
+	case ELFCLASS64:
+		btf__set_pointer_size(btf, 8);
+		break;
+	default:
+		pr_warn("failed to get ELF class (bitness) for %s\n", path);
+		break;
+	}
+
+	if (btf_ext && secs.btf_ext_data) {
+		*btf_ext = btf_ext__new(secs.btf_ext_data->d_buf, secs.btf_ext_data->d_size);
+		if (!*btf_ext) {
+			err = -errno;
+			goto done;
+		}
+	} else if (btf_ext) {
+		*btf_ext = NULL;
+	}
+
+	if (dist_base_btf)
+		btf->owns_base = true;
+done:
+	if (elf)
+		elf_end(elf);
+	close(fd);
+
+	if (!err)
+		return btf;
+
+	if (btf_ext)
+		btf_ext__free(*btf_ext);
+	btf__free(dist_base_btf);
+	btf__free(btf);
+
+	return ERR_PTR(err);
+}
+
+struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
+{
+	return libbpf_ptr(btf_parse_elf(path, NULL, btf_ext));
+}
+
+struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf)
+{
+	return libbpf_ptr(btf_parse_elf(path, base_btf, NULL));
+}
+
+static struct btf *btf_parse_raw(const char *path, struct btf *base_btf)
+{
+	struct btf *btf = NULL;
+	void *data = NULL;
+	FILE *f = NULL;
+	__u16 magic;
+	int err = 0;
+	long sz;
+
+	f = fopen(path, "rbe");
+	if (!f) {
+		err = -errno;
+		goto err_out;
+	}
+
+	/* check BTF magic */
+	if (fread(&magic, 1, sizeof(magic), f) < sizeof(magic)) {
+		err = -EIO;
+		goto err_out;
+	}
+	if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) {
+		/* definitely not a raw BTF */
+		err = -EPROTO;
+		goto err_out;
+	}
+
+	/* get file size */
+	if (fseek(f, 0, SEEK_END)) {
+		err = -errno;
+		goto err_out;
+	}
+	sz = ftell(f);
+	if (sz < 0) {
+		err = -errno;
+		goto err_out;
+	}
+	/* rewind to the start */
+	if (fseek(f, 0, SEEK_SET)) {
+		err = -errno;
+		goto err_out;
+	}
+
+	/* pre-alloc memory and read all of BTF data */
+	data = malloc(sz);
+	if (!data) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+	if (fread(data, 1, sz, f) < sz) {
+		err = -EIO;
+		goto err_out;
+	}
+
+	/* finally parse BTF data */
+	btf = btf_new(data, sz, base_btf, false);
+
+err_out:
+	free(data);
+	if (f)
+		fclose(f);
+	return err ? ERR_PTR(err) : btf;
+}
+
+struct btf *btf__parse_raw(const char *path)
+{
+	return libbpf_ptr(btf_parse_raw(path, NULL));
+}
+
+struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf)
+{
+	return libbpf_ptr(btf_parse_raw(path, base_btf));
+}
+
+static struct btf *btf_parse_raw_mmap(const char *path, struct btf *base_btf)
+{
+	struct stat st;
+	void *data;
+	struct btf *btf;
+	int fd, err;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return ERR_PTR(-errno);
+
+	if (fstat(fd, &st) < 0) {
+		err = -errno;
+		close(fd);
+		return ERR_PTR(err);
+	}
+
+	data = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	err = -errno;
+	close(fd);
+
+	if (data == MAP_FAILED)
+		return ERR_PTR(err);
+
+	btf = btf_new(data, st.st_size, base_btf, true);
+	if (IS_ERR(btf))
+		munmap(data, st.st_size);
+
+	return btf;
+}
+
+static struct btf *btf_parse(const char *path, struct btf *base_btf, struct btf_ext **btf_ext)
+{
+	struct btf *btf;
+	int err;
+
+	if (btf_ext)
+		*btf_ext = NULL;
+
+	btf = btf_parse_raw(path, base_btf);
+	err = libbpf_get_error(btf);
+	if (!err)
+		return btf;
+	if (err != -EPROTO)
+		return ERR_PTR(err);
+	return btf_parse_elf(path, base_btf, btf_ext);
+}
+
+struct btf *btf__parse(const char *path, struct btf_ext **btf_ext)
+{
+	return libbpf_ptr(btf_parse(path, NULL, btf_ext));
+}
+
+struct btf *btf__parse_split(const char *path, struct btf *base_btf)
+{
+	return libbpf_ptr(btf_parse(path, base_btf, NULL));
+}
+
+static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian);
+
+int btf_load_into_kernel(struct btf *btf,
+			 char *log_buf, size_t log_sz, __u32 log_level,
+			 int token_fd)
+{
+	LIBBPF_OPTS(bpf_btf_load_opts, opts);
+	__u32 buf_sz = 0, raw_size;
+	char *buf = NULL, *tmp;
+	void *raw_data;
+	int err = 0;
+
+	if (btf->fd >= 0)
+		return libbpf_err(-EEXIST);
+	if (log_sz && !log_buf)
+		return libbpf_err(-EINVAL);
+
+	/* cache native raw data representation */
+	raw_data = btf_get_raw_data(btf, &raw_size, false);
+	if (!raw_data) {
+		err = -ENOMEM;
+		goto done;
+	}
+	btf->raw_size = raw_size;
+	btf->raw_data = raw_data;
+
+retry_load:
+	/* if log_level is 0, we won't provide log_buf/log_size to the kernel,
+	 * initially. Only if BTF loading fails, we bump log_level to 1 and
+	 * retry, using either auto-allocated or custom log_buf. This way
+	 * non-NULL custom log_buf provides a buffer just in case, but hopes
+	 * for successful load and no need for log_buf.
+	 */
+	if (log_level) {
+		/* if caller didn't provide custom log_buf, we'll keep
+		 * allocating our own progressively bigger buffers for BTF
+		 * verification log
+		 */
+		if (!log_buf) {
+			buf_sz = max((__u32)BPF_LOG_BUF_SIZE, buf_sz * 2);
+			tmp = realloc(buf, buf_sz);
+			if (!tmp) {
+				err = -ENOMEM;
+				goto done;
+			}
+			buf = tmp;
+			buf[0] = '\0';
+		}
+
+		opts.log_buf = log_buf ? log_buf : buf;
+		opts.log_size = log_buf ? log_sz : buf_sz;
+		opts.log_level = log_level;
+	}
+
+	opts.token_fd = token_fd;
+	if (token_fd)
+		opts.btf_flags |= BPF_F_TOKEN_FD;
+
+	btf->fd = bpf_btf_load(raw_data, raw_size, &opts);
+	if (btf->fd < 0) {
+		/* time to turn on verbose mode and try again */
+		if (log_level == 0) {
+			log_level = 1;
+			goto retry_load;
+		}
+		/* only retry if caller didn't provide custom log_buf, but
+		 * make sure we can never overflow buf_sz
+		 */
+		if (!log_buf && errno == ENOSPC && buf_sz <= UINT_MAX / 2)
+			goto retry_load;
+
+		err = -errno;
+		pr_warn("BTF loading error: %s\n", errstr(err));
+		/* don't print out contents of custom log_buf */
+		if (!log_buf && buf[0])
+			pr_warn("-- BEGIN BTF LOAD LOG ---\n%s\n-- END BTF LOAD LOG --\n", buf);
+	}
+
+done:
+	free(buf);
+	return libbpf_err(err);
+}
+
+int btf__load_into_kernel(struct btf *btf)
+{
+	return btf_load_into_kernel(btf, NULL, 0, 0, 0);
+}
+
+int btf__fd(const struct btf *btf)
+{
+	return btf->fd;
+}
+
+void btf__set_fd(struct btf *btf, int fd)
+{
+	btf->fd = fd;
+}
+
+static const void *btf_strs_data(const struct btf *btf)
+{
+	return btf->strs_data ? btf->strs_data : strset__data(btf->strs_set);
+}
+
+static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian)
+{
+	const struct btf_header *hdr = &btf->hdr;
+	struct btf_type *t;
+	void *data, *p;
+	__u32 data_sz;
+	int i;
+
+	data = swap_endian ? btf->raw_data_swapped : btf->raw_data;
+	if (data) {
+		*size = btf->raw_size;
+		return data;
+	}
+
+	data_sz = hdr->hdr_len + hdr->type_len + hdr->str_len;
+	if (btf->layout)
+		data_sz += hdr->layout_len;
+
+	data = calloc(1, data_sz);
+	if (!data)
+		return NULL;
+	p = data;
+
+	memcpy(p, hdr, min((__u32)sizeof(struct btf_header), hdr->hdr_len));
+	if (swap_endian)
+		btf_bswap_hdr(p, hdr->hdr_len);
+	p += hdr->hdr_len;
+
+	memcpy(p, btf->types_data, hdr->type_len);
+	if (swap_endian) {
+		for (i = 0; i < btf->nr_types; i++) {
+			t = p + btf->type_offs[i];
+			/* btf_bswap_type_rest() relies on native t->info, so
+			 * we swap base type info after we swapped all the
+			 * additional information
+			 */
+			if (btf_bswap_type_rest(t))
+				goto err_out;
+			btf_bswap_type_base(t);
+		}
+	}
+	p += hdr->type_len;
+
+	if (btf->layout) {
+		memcpy(p, btf->layout, hdr->layout_len);
+		if (swap_endian) {
+			struct btf_layout *l, *end = p + hdr->layout_len;
+
+			for (l = p; l < end ; l++)
+				l->flags = bswap_16(l->flags);
+		}
+		p += hdr->layout_len;
+	}
+
+	memcpy(p, btf_strs_data(btf), hdr->str_len);
+
+	*size = data_sz;
+	return data;
+err_out:
+	free(data);
+	return NULL;
+}
+
+const void *btf__raw_data(const struct btf *btf_ro, __u32 *size)
+{
+	struct btf *btf = (struct btf *)btf_ro;
+	__u32 data_sz;
+	void *data;
+
+	data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian);
+	if (!data)
+		return errno = ENOMEM, NULL;
+
+	btf->raw_size = data_sz;
+	if (btf->swapped_endian)
+		btf->raw_data_swapped = data;
+	else
+		btf->raw_data = data;
+	*size = data_sz;
+	return data;
+}
+
+__attribute__((alias("btf__raw_data")))
+const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
+
+const char *btf__str_by_offset(const struct btf *btf, __u32 offset)
+{
+	if (offset < btf->start_str_off)
+		return btf__str_by_offset(btf->base_btf, offset);
+	else if (offset - btf->start_str_off < btf->hdr.str_len)
+		return btf_strs_data(btf) + (offset - btf->start_str_off);
+	else
+		return errno = EINVAL, NULL;
+}
+
+const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
+{
+	return btf__str_by_offset(btf, offset);
+}
+
+struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf)
+{
+	struct bpf_btf_info btf_info;
+	__u32 len = sizeof(btf_info);
+	__u32 last_size;
+	struct btf *btf;
+	void *ptr;
+	int err;
+
+	/* we won't know btf_size until we call bpf_btf_get_info_by_fd(). so
+	 * let's start with a sane default - 4KiB here - and resize it only if
+	 * bpf_btf_get_info_by_fd() needs a bigger buffer.
+	 */
+	last_size = 4096;
+	ptr = malloc(last_size);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	memset(&btf_info, 0, sizeof(btf_info));
+	btf_info.btf = ptr_to_u64(ptr);
+	btf_info.btf_size = last_size;
+	err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
+
+	if (!err && btf_info.btf_size > last_size) {
+		void *temp_ptr;
+
+		last_size = btf_info.btf_size;
+		temp_ptr = realloc(ptr, last_size);
+		if (!temp_ptr) {
+			btf = ERR_PTR(-ENOMEM);
+			goto exit_free;
+		}
+		ptr = temp_ptr;
+
+		len = sizeof(btf_info);
+		memset(&btf_info, 0, sizeof(btf_info));
+		btf_info.btf = ptr_to_u64(ptr);
+		btf_info.btf_size = last_size;
+
+		err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
+	}
+
+	if (err || btf_info.btf_size > last_size) {
+		btf = err ? ERR_PTR(-errno) : ERR_PTR(-E2BIG);
+		goto exit_free;
+	}
+
+	btf = btf_new(ptr, btf_info.btf_size, base_btf, false);
+
+exit_free:
+	free(ptr);
+	return btf;
+}
+
+struct btf *btf_load_from_kernel(__u32 id, struct btf *base_btf, int token_fd)
+{
+	struct btf *btf;
+	int btf_fd;
+	LIBBPF_OPTS(bpf_get_fd_by_id_opts, opts);
+
+	if (token_fd) {
+		opts.open_flags |= BPF_F_TOKEN_FD;
+		opts.token_fd = token_fd;
+	}
+
+	btf_fd = bpf_btf_get_fd_by_id_opts(id, &opts);
+	if (btf_fd < 0)
+		return libbpf_err_ptr(-errno);
+
+	btf = btf_get_from_fd(btf_fd, base_btf);
+	close(btf_fd);
+
+	return libbpf_ptr(btf);
+}
+
+struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf)
+{
+	return btf_load_from_kernel(id, base_btf, 0);
+}
+
+struct btf *btf__load_from_kernel_by_id(__u32 id)
+{
+	return btf__load_from_kernel_by_id_split(id, NULL);
+}
+
+static void btf_invalidate_raw_data(struct btf *btf)
+{
+	if (btf->raw_data)
+		btf_free_raw_data(btf);
+	if (btf->raw_data_swapped) {
+		free(btf->raw_data_swapped);
+		btf->raw_data_swapped = NULL;
+	}
+	btf->named_start_id = 0;
+}
+
+/* Ensure BTF is ready to be modified (by splitting into a three memory
+ * regions for types, strings and layout. Also invalidate cached
+ * raw_data, if any.
+ */
+static int btf_ensure_modifiable(struct btf *btf)
+{
+	void *types, *layout = NULL;
+	struct strset *set = NULL;
+	int err = -ENOMEM;
+
+	if (btf_is_modifiable(btf)) {
+		/* any BTF modification invalidates raw_data */
+		btf_invalidate_raw_data(btf);
+		return 0;
+	}
+
+	if (btf->has_hdr_extra) {
+		/* Additional BTF header data was found; not safe to modify. */
+		return -EOPNOTSUPP;
+	}
+
+	/* split raw data into memory regions; btf->hdr is done already. */
+	types = malloc(btf->hdr.type_len);
+	if (!types)
+		goto err_out;
+	memcpy(types, btf->types_data, btf->hdr.type_len);
+
+	if (btf->hdr.layout_len) {
+		layout = malloc(btf->hdr.layout_len);
+		if (!layout)
+			goto err_out;
+		memcpy(layout, btf->raw_data + btf->hdr.hdr_len + btf->hdr.layout_off,
+		       btf->hdr.layout_len);
+	}
+
+	/* build lookup index for all strings */
+	set = strset__new(BTF_MAX_STR_OFFSET, btf->strs_data, btf->hdr.str_len);
+	if (IS_ERR(set)) {
+		err = PTR_ERR(set);
+		goto err_out;
+	}
+
+	/* only when everything was successful, update internal state */
+	btf->types_data = types;
+	btf->types_data_cap = btf->hdr.type_len;
+	btf->strs_data = NULL;
+	btf->strs_set = set;
+	if (layout)
+		btf->layout = layout;
+	/* if BTF was created from scratch, all strings are guaranteed to be
+	 * unique and deduplicated
+	 */
+	if (btf->hdr.str_len == 0)
+		btf->strs_deduped = true;
+	if (!btf->base_btf && btf->hdr.str_len == 1)
+		btf->strs_deduped = true;
+
+	/* invalidate raw_data representation */
+	btf_invalidate_raw_data(btf);
+
+	btf->modifiable = true;
+
+	return 0;
+
+err_out:
+	strset__free(set);
+	free(types);
+	free(layout);
+	return err;
+}
+
+/* Find an offset in BTF string section that corresponds to a given string *s*.
+ * Returns:
+ *   - >0 offset into string section, if string is found;
+ *   - -ENOENT, if string is not in the string section;
+ *   - <0, on any other error.
+ */
+int btf__find_str(struct btf *btf, const char *s)
+{
+	int off;
+	int err;
+
+	if (btf->base_btf) {
+		off = btf__find_str(btf->base_btf, s);
+		if (off != -ENOENT)
+			return off;
+	}
+
+	/* BTF needs to be in a modifiable state to build string lookup index */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	off = strset__find_str(btf->strs_set, s);
+	if (off < 0)
+		return libbpf_err(off);
+
+	return btf->start_str_off + off;
+}
+
+/* Add a string s to the BTF string section.
+ * Returns:
+ *   - > 0 offset into string section, on success;
+ *   - < 0, on error.
+ */
+int btf__add_str(struct btf *btf, const char *s)
+{
+	int off;
+	int err;
+
+	if (btf->base_btf) {
+		off = btf__find_str(btf->base_btf, s);
+		if (off != -ENOENT)
+			return off;
+	}
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	off = strset__add_str(btf->strs_set, s);
+	if (off < 0)
+		return libbpf_err(off);
+
+	btf->hdr.str_len = strset__data_size(btf->strs_set);
+
+	return btf->start_str_off + off;
+}
+
+static void *btf_add_type_mem(struct btf *btf, size_t add_sz)
+{
+	return libbpf_add_mem(&btf->types_data, &btf->types_data_cap, 1,
+			      btf->hdr.type_len, UINT_MAX, add_sz);
+}
+
+static int btf_type_inc_vlen(struct btf_type *t)
+{
+	if (btf_vlen(t) == BTF_MAX_VLEN)
+		return -ENOSPC;
+	t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t));
+	return 0;
+}
+
+static void btf_hdr_update_type_len(struct btf *btf, int new_len)
+{
+	btf->hdr.type_len = new_len;
+	if (btf->layout) {
+		btf->hdr.layout_off = btf->hdr.type_off + new_len;
+		btf->hdr.str_off = btf->hdr.layout_off + btf->hdr.layout_len;
+	} else {
+		btf->hdr.str_off = btf->hdr.type_off + new_len;
+	}
+}
+
+static void btf_hdr_update_str_len(struct btf *btf, int new_len)
+{
+	btf->hdr.str_len = new_len;
+}
+
+static int btf_commit_type(struct btf *btf, int data_sz)
+{
+	int err;
+
+	err = btf_add_type_idx_entry(btf, btf->hdr.type_len);
+	if (err)
+		return libbpf_err(err);
+
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + data_sz);
+	btf->nr_types++;
+	return btf->start_id + btf->nr_types - 1;
+}
+
+struct btf_pipe {
+	const struct btf *src;
+	struct btf *dst;
+	struct hashmap *str_off_map; /* map string offsets from src to dst */
+};
+
+static int btf_rewrite_str(struct btf_pipe *p, __u32 *str_off)
+{
+	long mapped_off;
+	int off, err;
+
+	if (!*str_off) /* nothing to do for empty strings */
+		return 0;
+
+	if (p->str_off_map &&
+	    hashmap__find(p->str_off_map, *str_off, &mapped_off)) {
+		*str_off = mapped_off;
+		return 0;
+	}
+
+	off = btf__add_str(p->dst, btf__str_by_offset(p->src, *str_off));
+	if (off < 0)
+		return off;
+
+	/* Remember string mapping from src to dst.  It avoids
+	 * performing expensive string comparisons.
+	 */
+	if (p->str_off_map) {
+		err = hashmap__append(p->str_off_map, *str_off, off);
+		if (err)
+			return err;
+	}
+
+	*str_off = off;
+	return 0;
+}
+
+static int btf_add_type(struct btf_pipe *p, const struct btf_type *src_type)
+{
+	struct btf_field_iter it;
+	struct btf_type *t;
+	__u32 *str_off;
+	int sz, err;
+
+	sz = btf_type_size(p->src, src_type);
+	if (sz < 0)
+		return libbpf_err(sz);
+
+	/* deconstruct BTF, if necessary, and invalidate raw_data */
+	err = btf_ensure_modifiable(p->dst);
+	if (err)
+		return libbpf_err(err);
+
+	t = btf_add_type_mem(p->dst, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	memcpy(t, src_type, sz);
+
+	err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);
+	if (err)
+		return libbpf_err(err);
+
+	while ((str_off = btf_field_iter_next(&it))) {
+		err = btf_rewrite_str(p, str_off);
+		if (err)
+			return libbpf_err(err);
+	}
+
+	return btf_commit_type(p->dst, sz);
+}
+
+int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type)
+{
+	struct btf_pipe p = { .src = src_btf, .dst = btf };
+
+	return btf_add_type(&p, src_type);
+}
+
+static size_t btf_dedup_identity_hash_fn(long key, void *ctx);
+static bool btf_dedup_equal_fn(long k1, long k2, void *ctx);
+
+int btf__add_btf(struct btf *btf, const struct btf *src_btf)
+{
+	struct btf_pipe p = { .src = src_btf, .dst = btf };
+	int data_sz, sz, cnt, i, err, old_strs_len;
+	__u32 src_start_id;
+	__u32 *off;
+	void *t;
+
+	/*
+	 * When appending split BTF, the destination must share the same base
+	 * BTF so that base type ID references remain valid.
+	 */
+	if (src_btf->base_btf && src_btf->base_btf != btf->base_btf)
+		return libbpf_err(-EOPNOTSUPP);
+
+	src_start_id = src_btf->base_btf ? btf__type_cnt(src_btf->base_btf) : 1;
+
+	/* deconstruct BTF, if necessary, and invalidate raw_data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	/* remember original strings section size if we have to roll back
+	 * partial strings section changes
+	 */
+	old_strs_len = btf->hdr.str_len;
+
+	data_sz = src_btf->hdr.type_len;
+	cnt = src_btf->nr_types;
+
+	/* pre-allocate enough memory for new types */
+	t = btf_add_type_mem(btf, data_sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	/* pre-allocate enough memory for type offset index for new types */
+	off = btf_add_type_offs_mem(btf, cnt);
+	if (!off)
+		return libbpf_err(-ENOMEM);
+
+	/* Map the string offsets from src_btf to the offsets from btf to improve performance */
+	p.str_off_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL);
+	if (IS_ERR(p.str_off_map))
+		return libbpf_err(-ENOMEM);
+
+	/* bulk copy types data for all types from src_btf */
+	memcpy(t, src_btf->types_data, data_sz);
+
+	for (i = 0; i < cnt; i++) {
+		struct btf_field_iter it;
+		__u32 *type_id, *str_off;
+
+		sz = btf_type_size(src_btf, t);
+		if (sz < 0) {
+			/* unlikely, has to be corrupted src_btf */
+			err = sz;
+			goto err_out;
+		}
+
+		/* fill out type ID to type offset mapping for lookups by type ID */
+		*off = t - btf->types_data;
+
+		/* add, dedup, and remap strings referenced by this BTF type */
+		err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);
+		if (err)
+			goto err_out;
+		while ((str_off = btf_field_iter_next(&it))) {
+			/* don't remap strings from shared base BTF */
+			if (*str_off < src_btf->start_str_off)
+				continue;
+			err = btf_rewrite_str(&p, str_off);
+			if (err)
+				goto err_out;
+		}
+
+		/* remap all type IDs referenced from this BTF type */
+		err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);
+		if (err)
+			goto err_out;
+
+		while ((type_id = btf_field_iter_next(&it))) {
+			if (!*type_id) /* nothing to do for VOID references */
+				continue;
+
+			/* don't remap types from shared base BTF */
+			if (*type_id < src_start_id)
+				continue;
+
+			*type_id += btf->start_id + btf->nr_types - src_start_id;
+		}
+
+		/* go to next type data and type offset index entry */
+		t += sz;
+		off++;
+	}
+
+	/* Up until now any of the copied type data was effectively invisible,
+	 * so if we exited early before this point due to error, BTF would be
+	 * effectively unmodified. There would be extra internal memory
+	 * pre-allocated, but it would not be available for querying.  But now
+	 * that we've copied and rewritten all the data successfully, we can
+	 * update type count and various internal offsets and sizes to
+	 * "commit" the changes and made them visible to the outside world.
+	 */
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + data_sz);
+	btf->nr_types += cnt;
+
+	hashmap__free(p.str_off_map);
+
+	/* return type ID of the first added BTF type */
+	return btf->start_id + btf->nr_types - cnt;
+err_out:
+	/* zero out preallocated memory as if it was just allocated with
+	 * libbpf_add_mem()
+	 */
+	memset(btf->types_data + btf->hdr.type_len, 0, data_sz);
+	if (btf->strs_data)
+		memset(btf->strs_data + old_strs_len, 0, btf->hdr.str_len - old_strs_len);
+
+	/* and now restore original strings section size; types data size
+	 * wasn't modified, so doesn't need restoring, see big comment above
+	 */
+	btf_hdr_update_str_len(btf, old_strs_len);
+
+	hashmap__free(p.str_off_map);
+
+	return libbpf_err(err);
+}
+
+/*
+ * Append new BTF_KIND_INT type with:
+ *   - *name* - non-empty, non-NULL type name;
+ *   - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes;
+ *   - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL.
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding)
+{
+	struct btf_type *t;
+	int sz, name_off;
+	int err;
+
+	/* non-empty name */
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+	/* byte_sz must be power of 2 */
+	if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16)
+		return libbpf_err(-EINVAL);
+	if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL))
+		return libbpf_err(-EINVAL);
+
+	/* deconstruct BTF, if necessary, and invalidate raw_data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type) + sizeof(int);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	/* if something goes wrong later, we might end up with an extra string,
+	 * but that shouldn't be a problem, because BTF can't be constructed
+	 * completely anyway and will most probably be just discarded
+	 */
+	name_off = btf__add_str(btf, name);
+	if (name_off < 0)
+		return name_off;
+
+	t->name_off = name_off;
+	t->info = btf_type_info(BTF_KIND_INT, 0, 0);
+	t->size = byte_sz;
+	/* set INT info, we don't allow setting legacy bit offset/size */
+	*(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8);
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new BTF_KIND_FLOAT type with:
+ *   - *name* - non-empty, non-NULL type name;
+ *   - *sz* - size of the type, in bytes;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_float(struct btf *btf, const char *name, size_t byte_sz)
+{
+	struct btf_type *t;
+	int sz, name_off;
+	int err;
+
+	/* non-empty name */
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+
+	/* byte_sz must be one of the explicitly allowed values */
+	if (byte_sz != 2 && byte_sz != 4 && byte_sz != 8 && byte_sz != 12 &&
+	    byte_sz != 16)
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	name_off = btf__add_str(btf, name);
+	if (name_off < 0)
+		return name_off;
+
+	t->name_off = name_off;
+	t->info = btf_type_info(BTF_KIND_FLOAT, 0, 0);
+	t->size = byte_sz;
+
+	return btf_commit_type(btf, sz);
+}
+
+/* it's completely legal to append BTF types with type IDs pointing forward to
+ * types that haven't been appended yet, so we only make sure that id looks
+ * sane, we can't guarantee that ID will always be valid
+ */
+static int validate_type_id(int id)
+{
+	if (id < 0 || id > BTF_MAX_NR_TYPES)
+		return -EINVAL;
+	return 0;
+}
+
+/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */
+static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id, int kflag)
+{
+	struct btf_type *t;
+	int sz, name_off = 0;
+	int err;
+
+	if (validate_type_id(ref_type_id))
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	if (!str_is_empty(name)) {
+		name_off = btf__add_str(btf, name);
+		if (name_off < 0)
+			return name_off;
+	}
+
+	t->name_off = name_off;
+	t->info = btf_type_info(kind, 0, kflag);
+	t->type = ref_type_id;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new BTF_KIND_PTR type with:
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_ptr(struct btf *btf, int ref_type_id)
+{
+	return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id, 0);
+}
+
+/*
+ * Append new BTF_KIND_ARRAY type with:
+ *   - *index_type_id* - type ID of the type describing array index;
+ *   - *elem_type_id* - type ID of the type describing array element;
+ *   - *nr_elems* - the size of the array;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems)
+{
+	struct btf_type *t;
+	struct btf_array *a;
+	int err;
+	int sz;
+
+	if (validate_type_id(index_type_id) || validate_type_id(elem_type_id))
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type) + sizeof(struct btf_array);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	t->name_off = 0;
+	t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0);
+	t->size = 0;
+
+	a = btf_array(t);
+	a->type = elem_type_id;
+	a->index_type = index_type_id;
+	a->nelems = nr_elems;
+
+	return btf_commit_type(btf, sz);
+}
+
+/* generic STRUCT/UNION append function */
+static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz)
+{
+	struct btf_type *t;
+	int sz, name_off = 0;
+	int err;
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	if (!str_is_empty(name)) {
+		name_off = btf__add_str(btf, name);
+		if (name_off < 0)
+			return name_off;
+	}
+
+	/* start out with vlen=0 and no kflag; this will be adjusted when
+	 * adding each member
+	 */
+	t->name_off = name_off;
+	t->info = btf_type_info(kind, 0, 0);
+	t->size = bytes_sz;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new BTF_KIND_STRUCT type with:
+ *   - *name* - name of the struct, can be NULL or empty for anonymous structs;
+ *   - *byte_sz* - size of the struct, in bytes;
+ *
+ * Struct initially has no fields in it. Fields can be added by
+ * btf__add_field() right after btf__add_struct() succeeds.
+ *
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz)
+{
+	return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz);
+}
+
+/*
+ * Append new BTF_KIND_UNION type with:
+ *   - *name* - name of the union, can be NULL or empty for anonymous union;
+ *   - *byte_sz* - size of the union, in bytes;
+ *
+ * Union initially has no fields in it. Fields can be added by
+ * btf__add_field() right after btf__add_union() succeeds. All fields
+ * should have *bit_offset* of 0.
+ *
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz)
+{
+	return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz);
+}
+
+static struct btf_type *btf_last_type(struct btf *btf)
+{
+	return btf_type_by_id(btf, btf__type_cnt(btf) - 1);
+}
+
+/*
+ * Append new field for the current STRUCT/UNION type with:
+ *   - *name* - name of the field, can be NULL or empty for anonymous field;
+ *   - *type_id* - type ID for the type describing field type;
+ *   - *bit_offset* - bit offset of the start of the field within struct/union;
+ *   - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields;
+ * Returns:
+ *   -  0, on success;
+ *   - <0, on error.
+ */
+int btf__add_field(struct btf *btf, const char *name, int type_id,
+		   __u32 bit_offset, __u32 bit_size)
+{
+	struct btf_type *t;
+	struct btf_member *m;
+	bool is_bitfield;
+	int sz, name_off = 0;
+	int err;
+
+	/* last type should be union/struct */
+	if (btf->nr_types == 0)
+		return libbpf_err(-EINVAL);
+	t = btf_last_type(btf);
+	if (!btf_is_composite(t))
+		return libbpf_err(-EINVAL);
+	if (btf_vlen(t) == BTF_MAX_VLEN)
+		return libbpf_err(-ENOSPC);
+
+	if (validate_type_id(type_id))
+		return libbpf_err(-EINVAL);
+	/* best-effort bit field offset/size enforcement */
+	is_bitfield = bit_size || (bit_offset % 8 != 0);
+	if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff))
+		return libbpf_err(-EINVAL);
+
+	/* only offset 0 is allowed for unions */
+	if (btf_is_union(t) && bit_offset)
+		return libbpf_err(-EINVAL);
+
+	/* decompose and invalidate raw data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_member);
+	m = btf_add_type_mem(btf, sz);
+	if (!m)
+		return libbpf_err(-ENOMEM);
+
+	if (!str_is_empty(name)) {
+		name_off = btf__add_str(btf, name);
+		if (name_off < 0)
+			return name_off;
+	}
+
+	m->name_off = name_off;
+	m->type = type_id;
+	m->offset = bit_offset | (bit_size << 24);
+
+	/* btf_add_type_mem can invalidate t pointer */
+	t = btf_last_type(btf);
+
+	/* update parent type's vlen and kflag */
+	t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t));
+
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + sz);
+	return 0;
+}
+
+static int btf_add_enum_common(struct btf *btf, const char *name, __u32 byte_sz,
+			       bool is_signed, __u8 kind)
+{
+	struct btf_type *t;
+	int sz, name_off = 0;
+	int err;
+
+	/* byte_sz must be power of 2 */
+	if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8)
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	if (!str_is_empty(name)) {
+		name_off = btf__add_str(btf, name);
+		if (name_off < 0)
+			return name_off;
+	}
+
+	/* start out with vlen=0; it will be adjusted when adding enum values */
+	t->name_off = name_off;
+	t->info = btf_type_info(kind, 0, is_signed);
+	t->size = byte_sz;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new BTF_KIND_ENUM type with:
+ *   - *name* - name of the enum, can be NULL or empty for anonymous enums;
+ *   - *byte_sz* - size of the enum, in bytes.
+ *
+ * Enum initially has no enum values in it (and corresponds to enum forward
+ * declaration). Enumerator values can be added by btf__add_enum_value()
+ * immediately after btf__add_enum() succeeds.
+ *
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz)
+{
+	/*
+	 * set the signedness to be unsigned, it will change to signed
+	 * if any later enumerator is negative.
+	 */
+	return btf_add_enum_common(btf, name, byte_sz, false, BTF_KIND_ENUM);
+}
+
+/*
+ * Append new enum value for the current ENUM type with:
+ *   - *name* - name of the enumerator value, can't be NULL or empty;
+ *   - *value* - integer value corresponding to enum value *name*;
+ * Returns:
+ *   -  0, on success;
+ *   - <0, on error.
+ */
+int btf__add_enum_value(struct btf *btf, const char *name, __s64 value)
+{
+	struct btf_type *t;
+	struct btf_enum *v;
+	int sz, name_off;
+	int err;
+
+	/* last type should be BTF_KIND_ENUM */
+	if (btf->nr_types == 0)
+		return libbpf_err(-EINVAL);
+	t = btf_last_type(btf);
+	if (!btf_is_enum(t))
+		return libbpf_err(-EINVAL);
+
+	/* non-empty name */
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+	if (value < INT_MIN || value > UINT_MAX)
+		return libbpf_err(-E2BIG);
+
+	/* decompose and invalidate raw data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_enum);
+	v = btf_add_type_mem(btf, sz);
+	if (!v)
+		return libbpf_err(-ENOMEM);
+
+	name_off = btf__add_str(btf, name);
+	if (name_off < 0)
+		return name_off;
+
+	v->name_off = name_off;
+	v->val = value;
+
+	/* update parent type's vlen */
+	t = btf_last_type(btf);
+	err = btf_type_inc_vlen(t);
+	if (err)
+		return libbpf_err(err);
+
+	/* if negative value, set signedness to signed */
+	if (value < 0)
+		t->info = btf_type_info(btf_kind(t), btf_vlen(t), true);
+
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + sz);
+	return 0;
+}
+
+/*
+ * Append new BTF_KIND_ENUM64 type with:
+ *   - *name* - name of the enum, can be NULL or empty for anonymous enums;
+ *   - *byte_sz* - size of the enum, in bytes.
+ *   - *is_signed* - whether the enum values are signed or not;
+ *
+ * Enum initially has no enum values in it (and corresponds to enum forward
+ * declaration). Enumerator values can be added by btf__add_enum64_value()
+ * immediately after btf__add_enum64() succeeds.
+ *
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_enum64(struct btf *btf, const char *name, __u32 byte_sz,
+		    bool is_signed)
+{
+	return btf_add_enum_common(btf, name, byte_sz, is_signed,
+				   BTF_KIND_ENUM64);
+}
+
+/*
+ * Append new enum value for the current ENUM64 type with:
+ *   - *name* - name of the enumerator value, can't be NULL or empty;
+ *   - *value* - integer value corresponding to enum value *name*;
+ * Returns:
+ *   -  0, on success;
+ *   - <0, on error.
+ */
+int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value)
+{
+	struct btf_enum64 *v;
+	struct btf_type *t;
+	int sz, name_off;
+	int err;
+
+	/* last type should be BTF_KIND_ENUM64 */
+	if (btf->nr_types == 0)
+		return libbpf_err(-EINVAL);
+	t = btf_last_type(btf);
+	if (!btf_is_enum64(t))
+		return libbpf_err(-EINVAL);
+
+	/* non-empty name */
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+
+	/* decompose and invalidate raw data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_enum64);
+	v = btf_add_type_mem(btf, sz);
+	if (!v)
+		return libbpf_err(-ENOMEM);
+
+	name_off = btf__add_str(btf, name);
+	if (name_off < 0)
+		return name_off;
+
+	v->name_off = name_off;
+	v->val_lo32 = (__u32)value;
+	v->val_hi32 = value >> 32;
+
+	/* update parent type's vlen */
+	t = btf_last_type(btf);
+	err = btf_type_inc_vlen(t);
+	if (err)
+		return libbpf_err(err);
+
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + sz);
+	return 0;
+}
+
+/*
+ * Append new BTF_KIND_FWD type with:
+ *   - *name*, non-empty/non-NULL name;
+ *   - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT,
+ *     BTF_FWD_UNION, or BTF_FWD_ENUM;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind)
+{
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+
+	switch (fwd_kind) {
+	case BTF_FWD_STRUCT:
+	case BTF_FWD_UNION: {
+		struct btf_type *t;
+		int id;
+
+		id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0, 0);
+		if (id <= 0)
+			return id;
+		t = btf_type_by_id(btf, id);
+		t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION);
+		return id;
+	}
+	case BTF_FWD_ENUM:
+		/* enum forward in BTF currently is just an enum with no enum
+		 * values; we also assume a standard 4-byte size for it
+		 */
+		return btf__add_enum(btf, name, sizeof(int));
+	default:
+		return libbpf_err(-EINVAL);
+	}
+}
+
+/*
+ * Append new BTF_KING_TYPEDEF type with:
+ *   - *name*, non-empty/non-NULL name;
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id)
+{
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+
+	return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id, 0);
+}
+
+/*
+ * Append new BTF_KIND_VOLATILE type with:
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_volatile(struct btf *btf, int ref_type_id)
+{
+	return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id, 0);
+}
+
+/*
+ * Append new BTF_KIND_CONST type with:
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_const(struct btf *btf, int ref_type_id)
+{
+	return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id, 0);
+}
+
+/*
+ * Append new BTF_KIND_RESTRICT type with:
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_restrict(struct btf *btf, int ref_type_id)
+{
+	return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id, 0);
+}
+
+/*
+ * Append new BTF_KIND_TYPE_TAG type with:
+ *   - *value*, non-empty/non-NULL tag value;
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id)
+{
+	if (str_is_empty(value))
+		return libbpf_err(-EINVAL);
+
+	return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id, 0);
+}
+
+/*
+ * Append new BTF_KIND_TYPE_TAG type with:
+ *   - *value*, non-empty/non-NULL tag value;
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Set info->kflag to 1, indicating this tag is an __attribute__
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_type_attr(struct btf *btf, const char *value, int ref_type_id)
+{
+	if (str_is_empty(value))
+		return libbpf_err(-EINVAL);
+
+	return btf_add_ref_kind(btf, BTF_KIND_TYPE_TAG, value, ref_type_id, 1);
+}
+
+/*
+ * Append new BTF_KIND_FUNC type with:
+ *   - *name*, non-empty/non-NULL name;
+ *   - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_func(struct btf *btf, const char *name,
+		  enum btf_func_linkage linkage, int proto_type_id)
+{
+	int id;
+
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+	if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL &&
+	    linkage != BTF_FUNC_EXTERN)
+		return libbpf_err(-EINVAL);
+
+	id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id, 0);
+	if (id > 0) {
+		struct btf_type *t = btf_type_by_id(btf, id);
+
+		t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0);
+	}
+	return libbpf_err(id);
+}
+
+/*
+ * Append new BTF_KIND_FUNC_PROTO with:
+ *   - *ret_type_id* - type ID for return result of a function.
+ *
+ * Function prototype initially has no arguments, but they can be added by
+ * btf__add_func_param() one by one, immediately after
+ * btf__add_func_proto() succeeded.
+ *
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_func_proto(struct btf *btf, int ret_type_id)
+{
+	struct btf_type *t;
+	int err;
+	int sz;
+
+	if (validate_type_id(ret_type_id))
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	/* start out with vlen=0; this will be adjusted when adding enum
+	 * values, if necessary
+	 */
+	t->name_off = 0;
+	t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0);
+	t->type = ret_type_id;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new function parameter for current FUNC_PROTO type with:
+ *   - *name* - parameter name, can be NULL or empty;
+ *   - *type_id* - type ID describing the type of the parameter.
+ * Returns:
+ *   -  0, on success;
+ *   - <0, on error.
+ */
+int btf__add_func_param(struct btf *btf, const char *name, int type_id)
+{
+	struct btf_type *t;
+	struct btf_param *p;
+	int sz, name_off = 0;
+	int err;
+
+	if (validate_type_id(type_id))
+		return libbpf_err(-EINVAL);
+
+	/* last type should be BTF_KIND_FUNC_PROTO */
+	if (btf->nr_types == 0)
+		return libbpf_err(-EINVAL);
+	t = btf_last_type(btf);
+	if (!btf_is_func_proto(t))
+		return libbpf_err(-EINVAL);
+
+	/* decompose and invalidate raw data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_param);
+	p = btf_add_type_mem(btf, sz);
+	if (!p)
+		return libbpf_err(-ENOMEM);
+
+	if (!str_is_empty(name)) {
+		name_off = btf__add_str(btf, name);
+		if (name_off < 0)
+			return name_off;
+	}
+
+	p->name_off = name_off;
+	p->type = type_id;
+
+	/* update parent type's vlen */
+	t = btf_last_type(btf);
+	err = btf_type_inc_vlen(t);
+	if (err)
+		return libbpf_err(err);
+
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + sz);
+	return 0;
+}
+
+/*
+ * Append new BTF_KIND_VAR type with:
+ *   - *name* - non-empty/non-NULL name;
+ *   - *linkage* - variable linkage, one of BTF_VAR_STATIC,
+ *     BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN;
+ *   - *type_id* - type ID of the type describing the type of the variable.
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id)
+{
+	struct btf_type *t;
+	struct btf_var *v;
+	int sz, name_off;
+	int err;
+
+	/* non-empty name */
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+	if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED &&
+	    linkage != BTF_VAR_GLOBAL_EXTERN)
+		return libbpf_err(-EINVAL);
+	if (validate_type_id(type_id))
+		return libbpf_err(-EINVAL);
+
+	/* deconstruct BTF, if necessary, and invalidate raw_data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type) + sizeof(struct btf_var);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	name_off = btf__add_str(btf, name);
+	if (name_off < 0)
+		return name_off;
+
+	t->name_off = name_off;
+	t->info = btf_type_info(BTF_KIND_VAR, 0, 0);
+	t->type = type_id;
+
+	v = btf_var(t);
+	v->linkage = linkage;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new BTF_KIND_DATASEC type with:
+ *   - *name* - non-empty/non-NULL name;
+ *   - *byte_sz* - data section size, in bytes.
+ *
+ * Data section is initially empty. Variables info can be added with
+ * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds.
+ *
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz)
+{
+	struct btf_type *t;
+	int sz, name_off;
+	int err;
+
+	/* non-empty name */
+	if (str_is_empty(name))
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	name_off = btf__add_str(btf, name);
+	if (name_off < 0)
+		return name_off;
+
+	/* start with vlen=0, which will be update as var_secinfos are added */
+	t->name_off = name_off;
+	t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0);
+	t->size = byte_sz;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new data section variable information entry for current DATASEC type:
+ *   - *var_type_id* - type ID, describing type of the variable;
+ *   - *offset* - variable offset within data section, in bytes;
+ *   - *byte_sz* - variable size, in bytes.
+ *
+ * Returns:
+ *   -  0, on success;
+ *   - <0, on error.
+ */
+int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz)
+{
+	struct btf_type *t;
+	struct btf_var_secinfo *v;
+	int err;
+	int sz;
+
+	/* last type should be BTF_KIND_DATASEC */
+	if (btf->nr_types == 0)
+		return libbpf_err(-EINVAL);
+	t = btf_last_type(btf);
+	if (!btf_is_datasec(t))
+		return libbpf_err(-EINVAL);
+
+	if (validate_type_id(var_type_id))
+		return libbpf_err(-EINVAL);
+
+	/* decompose and invalidate raw data */
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_var_secinfo);
+	v = btf_add_type_mem(btf, sz);
+	if (!v)
+		return libbpf_err(-ENOMEM);
+
+	v->type = var_type_id;
+	v->offset = offset;
+	v->size = byte_sz;
+
+	/* update parent type's vlen */
+	t = btf_last_type(btf);
+	err = btf_type_inc_vlen(t);
+	if (err)
+		return libbpf_err(err);
+
+	btf_hdr_update_type_len(btf, btf->hdr.type_len + sz);
+	return 0;
+}
+
+static int btf_add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
+			    int component_idx, int kflag)
+{
+	struct btf_type *t;
+	int sz, value_off;
+	int err;
+
+	if (str_is_empty(value) || component_idx < -1)
+		return libbpf_err(-EINVAL);
+
+	if (validate_type_id(ref_type_id))
+		return libbpf_err(-EINVAL);
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		return libbpf_err(err);
+
+	sz = sizeof(struct btf_type) + sizeof(struct btf_decl_tag);
+	t = btf_add_type_mem(btf, sz);
+	if (!t)
+		return libbpf_err(-ENOMEM);
+
+	value_off = btf__add_str(btf, value);
+	if (value_off < 0)
+		return value_off;
+
+	t->name_off = value_off;
+	t->info = btf_type_info(BTF_KIND_DECL_TAG, 0, kflag);
+	t->type = ref_type_id;
+	btf_decl_tag(t)->component_idx = component_idx;
+
+	return btf_commit_type(btf, sz);
+}
+
+/*
+ * Append new BTF_KIND_DECL_TAG type with:
+ *   - *value* - non-empty/non-NULL string;
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ *   - *component_idx* - -1 for tagging reference type, otherwise struct/union
+ *     member or function argument index;
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
+		      int component_idx)
+{
+	return btf_add_decl_tag(btf, value, ref_type_id, component_idx, 0);
+}
+
+/*
+ * Append new BTF_KIND_DECL_TAG type with:
+ *   - *value* - non-empty/non-NULL string;
+ *   - *ref_type_id* - referenced type ID, it might not exist yet;
+ *   - *component_idx* - -1 for tagging reference type, otherwise struct/union
+ *     member or function argument index;
+ * Set info->kflag to 1, indicating this tag is an __attribute__
+ * Returns:
+ *   - >0, type ID of newly added BTF type;
+ *   - <0, on error.
+ */
+int btf__add_decl_attr(struct btf *btf, const char *value, int ref_type_id,
+		       int component_idx)
+{
+	return btf_add_decl_tag(btf, value, ref_type_id, component_idx, 1);
+}
+
+struct btf_ext_sec_info_param {
+	__u32 off;
+	__u32 len;
+	__u32 min_rec_size;
+	struct btf_ext_info *ext_info;
+	const char *desc;
+};
+
+/*
+ * Parse a single info subsection of the BTF.ext info data:
+ *  - validate subsection structure and elements
+ *  - save info subsection start and sizing details in struct btf_ext
+ *  - endian-independent operation, for calling before byte-swapping
+ */
+static int btf_ext_parse_sec_info(struct btf_ext *btf_ext,
+				  struct btf_ext_sec_info_param *ext_sec,
+				  bool is_native)
+{
+	const struct btf_ext_info_sec *sinfo;
+	struct btf_ext_info *ext_info;
+	__u32 info_left, record_size;
+	size_t sec_cnt = 0;
+	void *info;
+
+	if (ext_sec->len == 0)
+		return 0;
+
+	if (ext_sec->off & 0x03) {
+		pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n",
+		     ext_sec->desc);
+		return -EINVAL;
+	}
+
+	/* The start of the info sec (including the __u32 record_size). */
+	info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
+	info_left = ext_sec->len;
+
+	if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) {
+		pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
+			 ext_sec->desc, ext_sec->off, ext_sec->len);
+		return -EINVAL;
+	}
+
+	/* At least a record size */
+	if (info_left < sizeof(__u32)) {
+		pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc);
+		return -EINVAL;
+	}
+
+	/* The record size needs to meet either the minimum standard or, when
+	 * handling non-native endianness data, the exact standard so as
+	 * to allow safe byte-swapping.
+	 */
+	record_size = is_native ? *(__u32 *)info : bswap_32(*(__u32 *)info);
+	if (record_size < ext_sec->min_rec_size ||
+	    (!is_native && record_size != ext_sec->min_rec_size) ||
+	    record_size & 0x03) {
+		pr_debug("%s section in .BTF.ext has invalid record size %u\n",
+			 ext_sec->desc, record_size);
+		return -EINVAL;
+	}
+
+	sinfo = info + sizeof(__u32);
+	info_left -= sizeof(__u32);
+
+	/* If no records, return failure now so .BTF.ext won't be used. */
+	if (!info_left) {
+		pr_debug("%s section in .BTF.ext has no records\n", ext_sec->desc);
+		return -EINVAL;
+	}
+
+	while (info_left) {
+		unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
+		__u64 total_record_size;
+		__u32 num_records;
+
+		if (info_left < sec_hdrlen) {
+			pr_debug("%s section header is not found in .BTF.ext\n",
+			     ext_sec->desc);
+			return -EINVAL;
+		}
+
+		num_records = is_native ? sinfo->num_info : bswap_32(sinfo->num_info);
+		if (num_records == 0) {
+			pr_debug("%s section has incorrect num_records in .BTF.ext\n",
+			     ext_sec->desc);
+			return -EINVAL;
+		}
+
+		total_record_size = sec_hdrlen + (__u64)num_records * record_size;
+		if (info_left < total_record_size) {
+			pr_debug("%s section has incorrect num_records in .BTF.ext\n",
+			     ext_sec->desc);
+			return -EINVAL;
+		}
+
+		info_left -= total_record_size;
+		sinfo = (void *)sinfo + total_record_size;
+		sec_cnt++;
+	}
+
+	ext_info = ext_sec->ext_info;
+	ext_info->len = ext_sec->len - sizeof(__u32);
+	ext_info->rec_size = record_size;
+	ext_info->info = info + sizeof(__u32);
+	ext_info->sec_cnt = sec_cnt;
+
+	return 0;
+}
+
+/* Parse all info secs in the BTF.ext info data */
+static int btf_ext_parse_info(struct btf_ext *btf_ext, bool is_native)
+{
+	struct btf_ext_sec_info_param func_info = {
+		.off = btf_ext->hdr->func_info_off,
+		.len = btf_ext->hdr->func_info_len,
+		.min_rec_size = sizeof(struct bpf_func_info_min),
+		.ext_info = &btf_ext->func_info,
+		.desc = "func_info"
+	};
+	struct btf_ext_sec_info_param line_info = {
+		.off = btf_ext->hdr->line_info_off,
+		.len = btf_ext->hdr->line_info_len,
+		.min_rec_size = sizeof(struct bpf_line_info_min),
+		.ext_info = &btf_ext->line_info,
+		.desc = "line_info",
+	};
+	struct btf_ext_sec_info_param core_relo = {
+		.min_rec_size = sizeof(struct bpf_core_relo),
+		.ext_info = &btf_ext->core_relo_info,
+		.desc = "core_relo",
+	};
+	int err;
+
+	err = btf_ext_parse_sec_info(btf_ext, &func_info, is_native);
+	if (err)
+		return err;
+
+	err = btf_ext_parse_sec_info(btf_ext, &line_info, is_native);
+	if (err)
+		return err;
+
+	if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+		return 0; /* skip core relos parsing */
+
+	core_relo.off = btf_ext->hdr->core_relo_off;
+	core_relo.len = btf_ext->hdr->core_relo_len;
+	err = btf_ext_parse_sec_info(btf_ext, &core_relo, is_native);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* Swap byte-order of BTF.ext header with any endianness */
+static void btf_ext_bswap_hdr(struct btf_ext_header *h)
+{
+	bool is_native = h->magic == BTF_MAGIC;
+	__u32 hdr_len;
+
+	hdr_len = is_native ? h->hdr_len : bswap_32(h->hdr_len);
+
+	h->magic = bswap_16(h->magic);
+	h->hdr_len = bswap_32(h->hdr_len);
+	h->func_info_off = bswap_32(h->func_info_off);
+	h->func_info_len = bswap_32(h->func_info_len);
+	h->line_info_off = bswap_32(h->line_info_off);
+	h->line_info_len = bswap_32(h->line_info_len);
+
+	if (hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+		return;
+
+	h->core_relo_off = bswap_32(h->core_relo_off);
+	h->core_relo_len = bswap_32(h->core_relo_len);
+}
+
+/* Swap byte-order of generic info subsection */
+static void btf_ext_bswap_info_sec(void *info, __u32 len, bool is_native,
+				   info_rec_bswap_fn bswap_fn)
+{
+	struct btf_ext_info_sec *sec;
+	__u32 info_left, rec_size, *rs;
+
+	if (len == 0)
+		return;
+
+	rs = info;				/* info record size */
+	rec_size = is_native ? *rs : bswap_32(*rs);
+	*rs = bswap_32(*rs);
+
+	sec = info + sizeof(__u32);		/* info sec #1 */
+	info_left = len - sizeof(__u32);
+	while (info_left) {
+		unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
+		__u32 i, num_recs;
+		void *p;
+
+		num_recs = is_native ? sec->num_info : bswap_32(sec->num_info);
+		sec->sec_name_off = bswap_32(sec->sec_name_off);
+		sec->num_info = bswap_32(sec->num_info);
+		p = sec->data;			/* info rec #1 */
+		for (i = 0; i < num_recs; i++, p += rec_size)
+			bswap_fn(p);
+		sec = p;
+		info_left -= sec_hdrlen + (__u64)rec_size * num_recs;
+	}
+}
+
+/*
+ * Swap byte-order of all info data in a BTF.ext section
+ *  - requires BTF.ext hdr in native endianness
+ */
+static void btf_ext_bswap_info(struct btf_ext *btf_ext, void *data)
+{
+	const bool is_native = btf_ext->swapped_endian;
+	const struct btf_ext_header *h = data;
+	void *info;
+
+	/* Swap func_info subsection byte-order */
+	info = data + h->hdr_len + h->func_info_off;
+	btf_ext_bswap_info_sec(info, h->func_info_len, is_native,
+			       (info_rec_bswap_fn)bpf_func_info_bswap);
+
+	/* Swap line_info subsection byte-order */
+	info = data + h->hdr_len + h->line_info_off;
+	btf_ext_bswap_info_sec(info, h->line_info_len, is_native,
+			       (info_rec_bswap_fn)bpf_line_info_bswap);
+
+	/* Swap core_relo subsection byte-order (if present) */
+	if (h->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
+		return;
+
+	info = data + h->hdr_len + h->core_relo_off;
+	btf_ext_bswap_info_sec(info, h->core_relo_len, is_native,
+			       (info_rec_bswap_fn)bpf_core_relo_bswap);
+}
+
+/* Parse hdr data and info sections: check and convert to native endianness */
+static int btf_ext_parse(struct btf_ext *btf_ext)
+{
+	__u32 hdr_len, data_size = btf_ext->data_size;
+	struct btf_ext_header *hdr = btf_ext->hdr;
+	bool swapped_endian = false;
+	int err;
+
+	if (data_size < offsetofend(struct btf_ext_header, hdr_len)) {
+		pr_debug("BTF.ext header too short\n");
+		return -EINVAL;
+	}
+
+	hdr_len = hdr->hdr_len;
+	if (hdr->magic == bswap_16(BTF_MAGIC)) {
+		swapped_endian = true;
+		hdr_len = bswap_32(hdr_len);
+	} else if (hdr->magic != BTF_MAGIC) {
+		pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
+		return -EINVAL;
+	}
+
+	/* Ensure known version of structs, current BTF_VERSION == 1 */
+	if (hdr->version != 1) {
+		pr_debug("Unsupported BTF.ext version:%u\n", hdr->version);
+		return -ENOTSUP;
+	}
+
+	if (hdr->flags) {
+		pr_debug("Unsupported BTF.ext flags:%x\n", hdr->flags);
+		return -ENOTSUP;
+	}
+
+	if (data_size < hdr_len) {
+		pr_debug("BTF.ext header not found\n");
+		return -EINVAL;
+	} else if (data_size == hdr_len) {
+		pr_debug("BTF.ext has no data\n");
+		return -EINVAL;
+	}
+
+	/* Verify mandatory hdr info details present */
+	if (hdr_len < offsetofend(struct btf_ext_header, line_info_len)) {
+		pr_warn("BTF.ext header missing func_info, line_info\n");
+		return -EINVAL;
+	}
+
+	/* Keep hdr native byte-order in memory for introspection */
+	if (swapped_endian)
+		btf_ext_bswap_hdr(btf_ext->hdr);
+
+	/* Validate info subsections and cache key metadata */
+	err = btf_ext_parse_info(btf_ext, !swapped_endian);
+	if (err)
+		return err;
+
+	/* Keep infos native byte-order in memory for introspection */
+	if (swapped_endian)
+		btf_ext_bswap_info(btf_ext, btf_ext->data);
+
+	/*
+	 * Set btf_ext->swapped_endian only after all header and info data has
+	 * been swapped, helping bswap functions determine if their data are
+	 * in native byte-order when called.
+	 */
+	btf_ext->swapped_endian = swapped_endian;
+	return 0;
+}
+
+void btf_ext__free(struct btf_ext *btf_ext)
+{
+	if (IS_ERR_OR_NULL(btf_ext))
+		return;
+	free(btf_ext->func_info.sec_idxs);
+	free(btf_ext->line_info.sec_idxs);
+	free(btf_ext->core_relo_info.sec_idxs);
+	free(btf_ext->data);
+	free(btf_ext->data_swapped);
+	free(btf_ext);
+}
+
+struct btf_ext *btf_ext__new(const __u8 *data, __u32 size)
+{
+	struct btf_ext *btf_ext;
+	int err;
+
+	btf_ext = calloc(1, sizeof(struct btf_ext));
+	if (!btf_ext)
+		return libbpf_err_ptr(-ENOMEM);
+
+	btf_ext->data_size = size;
+	btf_ext->data = malloc(size);
+	if (!btf_ext->data) {
+		err = -ENOMEM;
+		goto done;
+	}
+	memcpy(btf_ext->data, data, size);
+
+	err = btf_ext_parse(btf_ext);
+
+done:
+	if (err) {
+		btf_ext__free(btf_ext);
+		return libbpf_err_ptr(err);
+	}
+
+	return btf_ext;
+}
+
+static void *btf_ext_raw_data(const struct btf_ext *btf_ext_ro, bool swap_endian)
+{
+	struct btf_ext *btf_ext = (struct btf_ext *)btf_ext_ro;
+	const __u32 data_sz = btf_ext->data_size;
+	void *data;
+
+	/* Return native data (always present) or swapped data if present */
+	if (!swap_endian)
+		return btf_ext->data;
+	else if (btf_ext->data_swapped)
+		return btf_ext->data_swapped;
+
+	/* Recreate missing swapped data, then cache and return */
+	data = calloc(1, data_sz);
+	if (!data)
+		return NULL;
+	memcpy(data, btf_ext->data, data_sz);
+
+	btf_ext_bswap_info(btf_ext, data);
+	btf_ext_bswap_hdr(data);
+	btf_ext->data_swapped = data;
+	return data;
+}
+
+const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size)
+{
+	void *data;
+
+	data = btf_ext_raw_data(btf_ext, btf_ext->swapped_endian);
+	if (!data)
+		return errno = ENOMEM, NULL;
+
+	*size = btf_ext->data_size;
+	return data;
+}
+
+__attribute__((alias("btf_ext__raw_data")))
+const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size);
+
+enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext)
+{
+	if (is_host_big_endian())
+		return btf_ext->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN;
+	else
+		return btf_ext->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
+}
+
+int btf_ext__set_endianness(struct btf_ext *btf_ext, enum btf_endianness endian)
+{
+	if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN)
+		return libbpf_err(-EINVAL);
+
+	btf_ext->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN);
+
+	if (!btf_ext->swapped_endian) {
+		free(btf_ext->data_swapped);
+		btf_ext->data_swapped = NULL;
+	}
+	return 0;
+}
+
+struct btf_dedup;
+
+static struct btf_dedup *btf_dedup_new(struct btf *btf, const struct btf_dedup_opts *opts);
+static void btf_dedup_free(struct btf_dedup *d);
+static int btf_dedup_prep(struct btf_dedup *d);
+static int btf_dedup_strings(struct btf_dedup *d);
+static int btf_dedup_prim_types(struct btf_dedup *d);
+static int btf_dedup_struct_types(struct btf_dedup *d);
+static int btf_dedup_ref_types(struct btf_dedup *d);
+static int btf_dedup_resolve_fwds(struct btf_dedup *d);
+static int btf_dedup_compact_types(struct btf_dedup *d);
+static int btf_dedup_remap_types(struct btf_dedup *d);
+
+/*
+ * Deduplicate BTF types and strings.
+ *
+ * BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF
+ * section with all BTF type descriptors and string data. It overwrites that
+ * memory in-place with deduplicated types and strings without any loss of
+ * information. If optional `struct btf_ext` representing '.BTF.ext' ELF section
+ * is provided, all the strings referenced from .BTF.ext section are honored
+ * and updated to point to the right offsets after deduplication.
+ *
+ * If function returns with error, type/string data might be garbled and should
+ * be discarded.
+ *
+ * More verbose and detailed description of both problem btf_dedup is solving,
+ * as well as solution could be found at:
+ * https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
+ *
+ * Problem description and justification
+ * =====================================
+ *
+ * BTF type information is typically emitted either as a result of conversion
+ * from DWARF to BTF or directly by compiler. In both cases, each compilation
+ * unit contains information about a subset of all the types that are used
+ * in an application. These subsets are frequently overlapping and contain a lot
+ * of duplicated information when later concatenated together into a single
+ * binary. This algorithm ensures that each unique type is represented by single
+ * BTF type descriptor, greatly reducing resulting size of BTF data.
+ *
+ * Compilation unit isolation and subsequent duplication of data is not the only
+ * problem. The same type hierarchy (e.g., struct and all the type that struct
+ * references) in different compilation units can be represented in BTF to
+ * various degrees of completeness (or, rather, incompleteness) due to
+ * struct/union forward declarations.
+ *
+ * Let's take a look at an example, that we'll use to better understand the
+ * problem (and solution). Suppose we have two compilation units, each using
+ * same `struct S`, but each of them having incomplete type information about
+ * struct's fields:
+ *
+ * // CU #1:
+ * struct S;
+ * struct A {
+ *	int a;
+ *	struct A* self;
+ *	struct S* parent;
+ * };
+ * struct B;
+ * struct S {
+ *	struct A* a_ptr;
+ *	struct B* b_ptr;
+ * };
+ *
+ * // CU #2:
+ * struct S;
+ * struct A;
+ * struct B {
+ *	int b;
+ *	struct B* self;
+ *	struct S* parent;
+ * };
+ * struct S {
+ *	struct A* a_ptr;
+ *	struct B* b_ptr;
+ * };
+ *
+ * In case of CU #1, BTF data will know only that `struct B` exist (but no
+ * more), but will know the complete type information about `struct A`. While
+ * for CU #2, it will know full type information about `struct B`, but will
+ * only know about forward declaration of `struct A` (in BTF terms, it will
+ * have `BTF_KIND_FWD` type descriptor with name `B`).
+ *
+ * This compilation unit isolation means that it's possible that there is no
+ * single CU with complete type information describing structs `S`, `A`, and
+ * `B`. Also, we might get tons of duplicated and redundant type information.
+ *
+ * Additional complication we need to keep in mind comes from the fact that
+ * types, in general, can form graphs containing cycles, not just DAGs.
+ *
+ * While algorithm does deduplication, it also merges and resolves type
+ * information (unless disabled throught `struct btf_opts`), whenever possible.
+ * E.g., in the example above with two compilation units having partial type
+ * information for structs `A` and `B`, the output of algorithm will emit
+ * a single copy of each BTF type that describes structs `A`, `B`, and `S`
+ * (as well as type information for `int` and pointers), as if they were defined
+ * in a single compilation unit as:
+ *
+ * struct A {
+ *	int a;
+ *	struct A* self;
+ *	struct S* parent;
+ * };
+ * struct B {
+ *	int b;
+ *	struct B* self;
+ *	struct S* parent;
+ * };
+ * struct S {
+ *	struct A* a_ptr;
+ *	struct B* b_ptr;
+ * };
+ *
+ * Algorithm summary
+ * =================
+ *
+ * Algorithm completes its work in 7 separate passes:
+ *
+ * 1. Strings deduplication.
+ * 2. Primitive types deduplication (int, enum, fwd).
+ * 3. Struct/union types deduplication.
+ * 4. Resolve unambiguous forward declarations.
+ * 5. Reference types deduplication (pointers, typedefs, arrays, funcs, func
+ *    protos, and const/volatile/restrict modifiers).
+ * 6. Types compaction.
+ * 7. Types remapping.
+ *
+ * Algorithm determines canonical type descriptor, which is a single
+ * representative type for each truly unique type. This canonical type is the
+ * one that will go into final deduplicated BTF type information. For
+ * struct/unions, it is also the type that algorithm will merge additional type
+ * information into (while resolving FWDs), as it discovers it from data in
+ * other CUs. Each input BTF type eventually gets either mapped to itself, if
+ * that type is canonical, or to some other type, if that type is equivalent
+ * and was chosen as canonical representative. This mapping is stored in
+ * `btf_dedup->map` array. This map is also used to record STRUCT/UNION that
+ * FWD type got resolved to.
+ *
+ * To facilitate fast discovery of canonical types, we also maintain canonical
+ * index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash
+ * (i.e., hashed kind, name, size, fields, etc) into a list of canonical types
+ * that match that signature. With sufficiently good choice of type signature
+ * hashing function, we can limit number of canonical types for each unique type
+ * signature to a very small number, allowing to find canonical type for any
+ * duplicated type very quickly.
+ *
+ * Struct/union deduplication is the most critical part and algorithm for
+ * deduplicating structs/unions is described in greater details in comments for
+ * `btf_dedup_is_equiv` function.
+ */
+int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts)
+{
+	struct btf_dedup *d;
+	int err;
+
+	if (!OPTS_VALID(opts, btf_dedup_opts))
+		return libbpf_err(-EINVAL);
+
+	d = btf_dedup_new(btf, opts);
+	if (IS_ERR(d)) {
+		pr_debug("btf_dedup_new failed: %ld\n", PTR_ERR(d));
+		return libbpf_err(-EINVAL);
+	}
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		goto done;
+
+	err = btf_dedup_prep(d);
+	if (err) {
+		pr_debug("btf_dedup_prep failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_strings(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_strings failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_prim_types(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_prim_types failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_struct_types(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_struct_types failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_resolve_fwds(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_resolve_fwds failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_ref_types(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_ref_types failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_compact_types(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_compact_types failed: %s\n", errstr(err));
+		goto done;
+	}
+	err = btf_dedup_remap_types(d);
+	if (err < 0) {
+		pr_debug("btf_dedup_remap_types failed: %s\n", errstr(err));
+		goto done;
+	}
+
+done:
+	btf_dedup_free(d);
+	return libbpf_err(err);
+}
+
+#define BTF_UNPROCESSED_ID ((__u32)-1)
+#define BTF_IN_PROGRESS_ID ((__u32)-2)
+
+struct btf_dedup {
+	/* .BTF section to be deduped in-place */
+	struct btf *btf;
+	/*
+	 * Optional .BTF.ext section. When provided, any strings referenced
+	 * from it will be taken into account when deduping strings
+	 */
+	struct btf_ext *btf_ext;
+	/*
+	 * This is a map from any type's signature hash to a list of possible
+	 * canonical representative type candidates. Hash collisions are
+	 * ignored, so even types of various kinds can share same list of
+	 * candidates, which is fine because we rely on subsequent
+	 * btf_xxx_equal() checks to authoritatively verify type equality.
+	 */
+	struct hashmap *dedup_table;
+	/* Canonical types map */
+	__u32 *map;
+	/* Hypothetical mapping, used during type graph equivalence checks */
+	__u32 *hypot_map;
+	__u32 *hypot_list;
+	size_t hypot_cnt;
+	size_t hypot_cap;
+	/* Whether hypothetical mapping, if successful, would need to adjust
+	 * already canonicalized types (due to a new forward declaration to
+	 * concrete type resolution). In such case, during split BTF dedup
+	 * candidate type would still be considered as different, because base
+	 * BTF is considered to be immutable.
+	 */
+	bool hypot_adjust_canon;
+	/* Various option modifying behavior of algorithm */
+	struct btf_dedup_opts opts;
+	/* temporary strings deduplication state */
+	struct strset *strs_set;
+};
+
+static unsigned long hash_combine(unsigned long h, unsigned long value)
+{
+	return h * 31 + value;
+}
+
+#define for_each_dedup_cand(d, node, hash) \
+	hashmap__for_each_key_entry(d->dedup_table, node, hash)
+
+static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id)
+{
+	return hashmap__append(d->dedup_table, hash, type_id);
+}
+
+static int btf_dedup_hypot_map_add(struct btf_dedup *d,
+				   __u32 from_id, __u32 to_id)
+{
+	if (d->hypot_cnt == d->hypot_cap) {
+		__u32 *new_list;
+
+		d->hypot_cap += max((size_t)16, d->hypot_cap / 2);
+		new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32));
+		if (!new_list)
+			return -ENOMEM;
+		d->hypot_list = new_list;
+	}
+	d->hypot_list[d->hypot_cnt++] = from_id;
+	d->hypot_map[from_id] = to_id;
+	return 0;
+}
+
+static void btf_dedup_clear_hypot_map(struct btf_dedup *d)
+{
+	int i;
+
+	for (i = 0; i < d->hypot_cnt; i++)
+		d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID;
+	d->hypot_cnt = 0;
+	d->hypot_adjust_canon = false;
+}
+
+static void btf_dedup_free(struct btf_dedup *d)
+{
+	hashmap__free(d->dedup_table);
+	d->dedup_table = NULL;
+
+	free(d->map);
+	d->map = NULL;
+
+	free(d->hypot_map);
+	d->hypot_map = NULL;
+
+	free(d->hypot_list);
+	d->hypot_list = NULL;
+
+	free(d);
+}
+
+static size_t btf_dedup_identity_hash_fn(long key, void *ctx)
+{
+	return key;
+}
+
+static size_t btf_dedup_collision_hash_fn(long key, void *ctx)
+{
+	return 0;
+}
+
+static bool btf_dedup_equal_fn(long k1, long k2, void *ctx)
+{
+	return k1 == k2;
+}
+
+static struct btf_dedup *btf_dedup_new(struct btf *btf, const struct btf_dedup_opts *opts)
+{
+	struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup));
+	hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn;
+	int i, err = 0, type_cnt;
+
+	if (!d)
+		return ERR_PTR(-ENOMEM);
+
+	if (OPTS_GET(opts, force_collisions, false))
+		hash_fn = btf_dedup_collision_hash_fn;
+
+	d->btf = btf;
+	d->btf_ext = OPTS_GET(opts, btf_ext, NULL);
+
+	d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL);
+	if (IS_ERR(d->dedup_table)) {
+		err = PTR_ERR(d->dedup_table);
+		d->dedup_table = NULL;
+		goto done;
+	}
+
+	type_cnt = btf__type_cnt(btf);
+	d->map = malloc(sizeof(__u32) * type_cnt);
+	if (!d->map) {
+		err = -ENOMEM;
+		goto done;
+	}
+	/* special BTF "void" type is made canonical immediately */
+	d->map[0] = 0;
+	for (i = 1; i < type_cnt; i++) {
+		struct btf_type *t = btf_type_by_id(d->btf, i);
+
+		/* VAR and DATASEC are never deduped and are self-canonical */
+		if (btf_is_var(t) || btf_is_datasec(t))
+			d->map[i] = i;
+		else
+			d->map[i] = BTF_UNPROCESSED_ID;
+	}
+
+	d->hypot_map = malloc(sizeof(__u32) * type_cnt);
+	if (!d->hypot_map) {
+		err = -ENOMEM;
+		goto done;
+	}
+	for (i = 0; i < type_cnt; i++)
+		d->hypot_map[i] = BTF_UNPROCESSED_ID;
+
+done:
+	if (err) {
+		btf_dedup_free(d);
+		return ERR_PTR(err);
+	}
+
+	return d;
+}
+
+/*
+ * Iterate over all possible places in .BTF and .BTF.ext that can reference
+ * string and pass pointer to it to a provided callback `fn`.
+ */
+static int btf_for_each_str_off(struct btf_dedup *d, str_off_visit_fn fn, void *ctx)
+{
+	int i, r;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		struct btf_field_iter it;
+		struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i);
+		__u32 *str_off;
+
+		r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);
+		if (r)
+			return r;
+
+		while ((str_off = btf_field_iter_next(&it))) {
+			r = fn(str_off, ctx);
+			if (r)
+				return r;
+		}
+	}
+
+	if (!d->btf_ext)
+		return 0;
+
+	r = btf_ext_visit_str_offs(d->btf_ext, fn, ctx);
+	if (r)
+		return r;
+
+	return 0;
+}
+
+static int strs_dedup_remap_str_off(__u32 *str_off_ptr, void *ctx)
+{
+	struct btf_dedup *d = ctx;
+	__u32 str_off = *str_off_ptr;
+	const char *s;
+	int off, err;
+
+	/* don't touch empty string or string in main BTF */
+	if (str_off == 0 || str_off < d->btf->start_str_off)
+		return 0;
+
+	s = btf__str_by_offset(d->btf, str_off);
+	if (d->btf->base_btf) {
+		err = btf__find_str(d->btf->base_btf, s);
+		if (err >= 0) {
+			*str_off_ptr = err;
+			return 0;
+		}
+		if (err != -ENOENT)
+			return err;
+	}
+
+	off = strset__add_str(d->strs_set, s);
+	if (off < 0)
+		return off;
+
+	*str_off_ptr = d->btf->start_str_off + off;
+	return 0;
+}
+
+/*
+ * Dedup string and filter out those that are not referenced from either .BTF
+ * or .BTF.ext (if provided) sections.
+ *
+ * This is done by building index of all strings in BTF's string section,
+ * then iterating over all entities that can reference strings (e.g., type
+ * names, struct field names, .BTF.ext line info, etc) and marking corresponding
+ * strings as used. After that all used strings are deduped and compacted into
+ * sequential blob of memory and new offsets are calculated. Then all the string
+ * references are iterated again and rewritten using new offsets.
+ */
+static int btf_dedup_strings(struct btf_dedup *d)
+{
+	int err;
+
+	if (d->btf->strs_deduped)
+		return 0;
+
+	d->strs_set = strset__new(BTF_MAX_STR_OFFSET, NULL, 0);
+	if (IS_ERR(d->strs_set)) {
+		err = PTR_ERR(d->strs_set);
+		goto err_out;
+	}
+
+	if (!d->btf->base_btf) {
+		/* insert empty string; we won't be looking it up during strings
+		 * dedup, but it's good to have it for generic BTF string lookups
+		 */
+		err = strset__add_str(d->strs_set, "");
+		if (err < 0)
+			goto err_out;
+	}
+
+	/* remap string offsets */
+	err = btf_for_each_str_off(d, strs_dedup_remap_str_off, d);
+	if (err)
+		goto err_out;
+
+	/* replace BTF string data and hash with deduped ones */
+	strset__free(d->btf->strs_set);
+	btf_hdr_update_str_len(d->btf, strset__data_size(d->strs_set));
+	d->btf->strs_set = d->strs_set;
+	d->strs_set = NULL;
+	d->btf->strs_deduped = true;
+	return 0;
+
+err_out:
+	strset__free(d->strs_set);
+	d->strs_set = NULL;
+
+	return err;
+}
+
+/*
+ * Calculate type signature hash of TYPEDEF, ignoring referenced type IDs,
+ * as referenced type IDs equivalence is established separately during type
+ * graph equivalence check algorithm.
+ */
+static long btf_hash_typedef(struct btf_type *t)
+{
+	long h;
+
+	h = hash_combine(0, t->name_off);
+	h = hash_combine(h, t->info);
+	return h;
+}
+
+static long btf_hash_common(struct btf_type *t)
+{
+	long h;
+
+	h = hash_combine(0, t->name_off);
+	h = hash_combine(h, t->info);
+	h = hash_combine(h, t->size);
+	return h;
+}
+
+static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2)
+{
+	return t1->name_off == t2->name_off &&
+	       t1->info == t2->info &&
+	       t1->size == t2->size;
+}
+
+/* Check structural compatibility of two TYPEDEF. */
+static bool btf_equal_typedef(struct btf_type *t1, struct btf_type *t2)
+{
+	return t1->name_off == t2->name_off &&
+	       t1->info == t2->info;
+}
+
+/* Calculate type signature hash of INT or TAG. */
+static long btf_hash_int_decl_tag(struct btf_type *t)
+{
+	__u32 info = *(__u32 *)(t + 1);
+	long h;
+
+	h = btf_hash_common(t);
+	h = hash_combine(h, info);
+	return h;
+}
+
+/* Check structural equality of two INTs or TAGs. */
+static bool btf_equal_int_tag(struct btf_type *t1, struct btf_type *t2)
+{
+	__u32 info1, info2;
+
+	if (!btf_equal_common(t1, t2))
+		return false;
+	info1 = *(__u32 *)(t1 + 1);
+	info2 = *(__u32 *)(t2 + 1);
+	return info1 == info2;
+}
+
+/* Calculate type signature hash of ENUM/ENUM64. */
+static long btf_hash_enum(struct btf_type *t)
+{
+	long h;
+
+	/* don't hash vlen, enum members and size to support enum fwd resolving */
+	h = hash_combine(0, t->name_off);
+	return h;
+}
+
+static bool btf_equal_enum_members(struct btf_type *t1, struct btf_type *t2)
+{
+	const struct btf_enum *m1, *m2;
+	__u32 vlen;
+	int i;
+
+	vlen = btf_vlen(t1);
+	m1 = btf_enum(t1);
+	m2 = btf_enum(t2);
+	for (i = 0; i < vlen; i++) {
+		if (m1->name_off != m2->name_off || m1->val != m2->val)
+			return false;
+		m1++;
+		m2++;
+	}
+	return true;
+}
+
+static bool btf_equal_enum64_members(struct btf_type *t1, struct btf_type *t2)
+{
+	const struct btf_enum64 *m1, *m2;
+	__u32 vlen;
+	int i;
+
+	vlen = btf_vlen(t1);
+	m1 = btf_enum64(t1);
+	m2 = btf_enum64(t2);
+	for (i = 0; i < vlen; i++) {
+		if (m1->name_off != m2->name_off || m1->val_lo32 != m2->val_lo32 ||
+		    m1->val_hi32 != m2->val_hi32)
+			return false;
+		m1++;
+		m2++;
+	}
+	return true;
+}
+
+/* Check structural equality of two ENUMs or ENUM64s. */
+static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
+{
+	if (!btf_equal_common(t1, t2))
+		return false;
+
+	/* t1 & t2 kinds are identical because of btf_equal_common */
+	if (btf_kind(t1) == BTF_KIND_ENUM)
+		return btf_equal_enum_members(t1, t2);
+	else
+		return btf_equal_enum64_members(t1, t2);
+}
+
+static inline bool btf_is_enum_fwd(struct btf_type *t)
+{
+	return btf_is_any_enum(t) && btf_vlen(t) == 0;
+}
+
+static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
+{
+	if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
+		return btf_equal_enum(t1, t2);
+	/* At this point either t1 or t2 or both are forward declarations, thus:
+	 * - skip comparing vlen because it is zero for forward declarations;
+	 * - skip comparing size to allow enum forward declarations
+	 *   to be compatible with enum64 full declarations;
+	 * - skip comparing kind for the same reason.
+	 */
+	return t1->name_off == t2->name_off &&
+	       btf_is_any_enum(t1) && btf_is_any_enum(t2);
+}
+
+/*
+ * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,
+ * as referenced type IDs equivalence is established separately during type
+ * graph equivalence check algorithm.
+ */
+static long btf_hash_struct(struct btf_type *t)
+{
+	const struct btf_member *member = btf_members(t);
+	__u32 vlen = btf_vlen(t);
+	long h = btf_hash_common(t);
+	int i;
+
+	for (i = 0; i < vlen; i++) {
+		h = hash_combine(h, member->name_off);
+		h = hash_combine(h, member->offset);
+		/* no hashing of referenced type ID, it can be unresolved yet */
+		member++;
+	}
+	return h;
+}
+
+/*
+ * Check structural compatibility of two STRUCTs/UNIONs, ignoring referenced
+ * type IDs. This check is performed during type graph equivalence check and
+ * referenced types equivalence is checked separately.
+ */
+static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2)
+{
+	const struct btf_member *m1, *m2;
+	__u32 vlen;
+	int i;
+
+	if (!btf_equal_common(t1, t2))
+		return false;
+
+	vlen = btf_vlen(t1);
+	m1 = btf_members(t1);
+	m2 = btf_members(t2);
+	for (i = 0; i < vlen; i++) {
+		if (m1->name_off != m2->name_off || m1->offset != m2->offset)
+			return false;
+		m1++;
+		m2++;
+	}
+	return true;
+}
+
+/*
+ * Calculate type signature hash of ARRAY, including referenced type IDs,
+ * under assumption that they were already resolved to canonical type IDs and
+ * are not going to change.
+ */
+static long btf_hash_array(struct btf_type *t)
+{
+	const struct btf_array *info = btf_array(t);
+	long h = btf_hash_common(t);
+
+	h = hash_combine(h, info->type);
+	h = hash_combine(h, info->index_type);
+	h = hash_combine(h, info->nelems);
+	return h;
+}
+
+/*
+ * Check exact equality of two ARRAYs, taking into account referenced
+ * type IDs, under assumption that they were already resolved to canonical
+ * type IDs and are not going to change.
+ * This function is called during reference types deduplication to compare
+ * ARRAY to potential canonical representative.
+ */
+static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2)
+{
+	const struct btf_array *info1, *info2;
+
+	if (!btf_equal_common(t1, t2))
+		return false;
+
+	info1 = btf_array(t1);
+	info2 = btf_array(t2);
+	return info1->type == info2->type &&
+	       info1->index_type == info2->index_type &&
+	       info1->nelems == info2->nelems;
+}
+
+/*
+ * Check structural compatibility of two ARRAYs, ignoring referenced type
+ * IDs. This check is performed during type graph equivalence check and
+ * referenced types equivalence is checked separately.
+ */
+static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2)
+{
+	if (!btf_equal_common(t1, t2))
+		return false;
+
+	return btf_array(t1)->nelems == btf_array(t2)->nelems;
+}
+
+/*
+ * Calculate type signature hash of FUNC_PROTO, including referenced type IDs,
+ * under assumption that they were already resolved to canonical type IDs and
+ * are not going to change.
+ */
+static long btf_hash_fnproto(struct btf_type *t)
+{
+	const struct btf_param *member = btf_params(t);
+	__u32 vlen = btf_vlen(t);
+	long h = btf_hash_common(t);
+	int i;
+
+	for (i = 0; i < vlen; i++) {
+		h = hash_combine(h, member->name_off);
+		h = hash_combine(h, member->type);
+		member++;
+	}
+	return h;
+}
+
+/*
+ * Check exact equality of two FUNC_PROTOs, taking into account referenced
+ * type IDs, under assumption that they were already resolved to canonical
+ * type IDs and are not going to change.
+ * This function is called during reference types deduplication to compare
+ * FUNC_PROTO to potential canonical representative.
+ */
+static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2)
+{
+	const struct btf_param *m1, *m2;
+	__u32 vlen;
+	int i;
+
+	if (!btf_equal_common(t1, t2))
+		return false;
+
+	vlen = btf_vlen(t1);
+	m1 = btf_params(t1);
+	m2 = btf_params(t2);
+	for (i = 0; i < vlen; i++) {
+		if (m1->name_off != m2->name_off || m1->type != m2->type)
+			return false;
+		m1++;
+		m2++;
+	}
+	return true;
+}
+
+/*
+ * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
+ * IDs. This check is performed during type graph equivalence check and
+ * referenced types equivalence is checked separately.
+ */
+static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2)
+{
+	const struct btf_param *m1, *m2;
+	__u32 vlen;
+	int i;
+
+	/* skip return type ID */
+	if (t1->name_off != t2->name_off || t1->info != t2->info)
+		return false;
+
+	vlen = btf_vlen(t1);
+	m1 = btf_params(t1);
+	m2 = btf_params(t2);
+	for (i = 0; i < vlen; i++) {
+		if (m1->name_off != m2->name_off)
+			return false;
+		m1++;
+		m2++;
+	}
+	return true;
+}
+
+/* Prepare split BTF for deduplication by calculating hashes of base BTF's
+ * types and initializing the rest of the state (canonical type mapping) for
+ * the fixed base BTF part.
+ */
+static int btf_dedup_prep(struct btf_dedup *d)
+{
+	struct btf_type *t;
+	int type_id;
+	long h;
+
+	if (!d->btf->base_btf)
+		return 0;
+
+	for (type_id = 1; type_id < d->btf->start_id; type_id++) {
+		t = btf_type_by_id(d->btf, type_id);
+
+		/* all base BTF types are self-canonical by definition */
+		d->map[type_id] = type_id;
+
+		switch (btf_kind(t)) {
+		case BTF_KIND_VAR:
+		case BTF_KIND_DATASEC:
+			/* VAR and DATASEC are never hash/deduplicated */
+			continue;
+		case BTF_KIND_CONST:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_PTR:
+		case BTF_KIND_FWD:
+		case BTF_KIND_FUNC:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_TYPE_TAG:
+			h = btf_hash_common(t);
+			break;
+		case BTF_KIND_TYPEDEF:
+			h = btf_hash_typedef(t);
+			break;
+		case BTF_KIND_INT:
+		case BTF_KIND_DECL_TAG:
+			h = btf_hash_int_decl_tag(t);
+			break;
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+			h = btf_hash_enum(t);
+			break;
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			h = btf_hash_struct(t);
+			break;
+		case BTF_KIND_ARRAY:
+			h = btf_hash_array(t);
+			break;
+		case BTF_KIND_FUNC_PROTO:
+			h = btf_hash_fnproto(t);
+			break;
+		default:
+			pr_debug("unknown kind %d for type [%d]\n", btf_kind(t), type_id);
+			return -EINVAL;
+		}
+		if (btf_dedup_table_add(d, h, type_id))
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/*
+ * Deduplicate primitive types, that can't reference other types, by calculating
+ * their type signature hash and comparing them with any possible canonical
+ * candidate. If no canonical candidate matches, type itself is marked as
+ * canonical and is added into `btf_dedup->dedup_table` as another candidate.
+ */
+static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
+{
+	struct btf_type *t = btf_type_by_id(d->btf, type_id);
+	struct hashmap_entry *hash_entry;
+	struct btf_type *cand;
+	/* if we don't find equivalent type, then we are canonical */
+	__u32 new_id = type_id;
+	__u32 cand_id;
+	long h;
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_ARRAY:
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_FUNC_PROTO:
+	case BTF_KIND_VAR:
+	case BTF_KIND_DATASEC:
+	case BTF_KIND_DECL_TAG:
+	case BTF_KIND_TYPE_TAG:
+		return 0;
+
+	case BTF_KIND_INT:
+		h = btf_hash_int_decl_tag(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_int_tag(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+		}
+		break;
+
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		h = btf_hash_enum(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_enum(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+			if (btf_compat_enum(t, cand)) {
+				if (btf_is_enum_fwd(t)) {
+					/* resolve fwd to full enum */
+					new_id = cand_id;
+					break;
+				}
+				/* resolve canonical enum fwd to full enum */
+				d->map[cand_id] = type_id;
+			}
+		}
+		break;
+
+	case BTF_KIND_FWD:
+	case BTF_KIND_FLOAT:
+		h = btf_hash_common(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_common(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+		}
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	d->map[type_id] = new_id;
+	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int btf_dedup_prim_types(struct btf_dedup *d)
+{
+	int i, err;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		err = btf_dedup_prim_type(d, d->btf->start_id + i);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/*
+ * Check whether type is already mapped into canonical one (could be to itself).
+ */
+static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id)
+{
+	return d->map[type_id] <= BTF_MAX_NR_TYPES;
+}
+
+/*
+ * Resolve type ID into its canonical type ID, if any; otherwise return original
+ * type ID. If type is FWD and is resolved into STRUCT/UNION already, follow
+ * STRUCT/UNION link and resolve it into canonical type ID as well.
+ */
+static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id)
+{
+	while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
+		type_id = d->map[type_id];
+	return type_id;
+}
+
+/*
+ * Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original
+ * type ID.
+ */
+static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id)
+{
+	__u32 orig_type_id = type_id;
+
+	if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
+		return type_id;
+
+	while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
+		type_id = d->map[type_id];
+
+	if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
+		return type_id;
+
+	return orig_type_id;
+}
+
+
+static inline __u16 btf_fwd_kind(struct btf_type *t)
+{
+	return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT;
+}
+
+static bool btf_dedup_identical_types(struct btf_dedup *d, __u32 id1, __u32 id2, int depth)
+{
+	struct btf_type *t1, *t2;
+	int k1, k2;
+recur:
+	t1 = btf_type_by_id(d->btf, id1);
+	t2 = btf_type_by_id(d->btf, id2);
+	if (depth <= 0) {
+		pr_debug("Reached depth limit for identical type comparison for '%s'/'%s'\n",
+			 btf__name_by_offset(d->btf, t1->name_off),
+			 btf__name_by_offset(d->btf, t2->name_off));
+		return false;
+	}
+
+	k1 = btf_kind(t1);
+	k2 = btf_kind(t2);
+	if (k1 != k2)
+		return false;
+
+	switch (k1) {
+	case BTF_KIND_UNKN: /* VOID */
+		return true;
+	case BTF_KIND_INT:
+		return btf_equal_int_tag(t1, t2);
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		return btf_compat_enum(t1, t2);
+	case BTF_KIND_FWD:
+	case BTF_KIND_FLOAT:
+		return btf_equal_common(t1, t2);
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_TYPE_TAG:
+		if (t1->info != t2->info || t1->name_off != t2->name_off)
+			return false;
+		id1 = t1->type;
+		id2 = t2->type;
+		goto recur;
+	case BTF_KIND_ARRAY: {
+		struct btf_array *a1, *a2;
+
+		if (!btf_compat_array(t1, t2))
+			return false;
+
+		a1 = btf_array(t1);
+		a2 = btf_array(t1);
+
+		if (a1->index_type != a2->index_type &&
+		    !btf_dedup_identical_types(d, a1->index_type, a2->index_type, depth - 1))
+			return false;
+
+		if (a1->type != a2->type &&
+		    !btf_dedup_identical_types(d, a1->type, a2->type, depth - 1))
+			return false;
+
+		return true;
+	}
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m1, *m2;
+		int i, n;
+
+		if (!btf_shallow_equal_struct(t1, t2))
+			return false;
+
+		m1 = btf_members(t1);
+		m2 = btf_members(t2);
+		for (i = 0, n = btf_vlen(t1); i < n; i++, m1++, m2++) {
+			if (m1->type == m2->type)
+				continue;
+			if (!btf_dedup_identical_types(d, m1->type, m2->type, depth - 1)) {
+				if (t1->name_off) {
+					pr_debug("%s '%s' size=%u vlen=%u id1[%u] id2[%u] shallow-equal but not identical for field#%d '%s'\n",
+						 k1 == BTF_KIND_STRUCT ? "STRUCT" : "UNION",
+						 btf__name_by_offset(d->btf, t1->name_off),
+						 t1->size, btf_vlen(t1), id1, id2, i,
+						 btf__name_by_offset(d->btf, m1->name_off));
+				}
+				return false;
+			}
+		}
+		return true;
+	}
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *p1, *p2;
+		int i, n;
+
+		if (!btf_compat_fnproto(t1, t2))
+			return false;
+
+		if (t1->type != t2->type &&
+		    !btf_dedup_identical_types(d, t1->type, t2->type, depth - 1))
+			return false;
+
+		p1 = btf_params(t1);
+		p2 = btf_params(t2);
+		for (i = 0, n = btf_vlen(t1); i < n; i++, p1++, p2++) {
+			if (p1->type == p2->type)
+				continue;
+			if (!btf_dedup_identical_types(d, p1->type, p2->type, depth - 1))
+				return false;
+		}
+		return true;
+	}
+	default:
+		return false;
+	}
+}
+
+
+/*
+ * Check equivalence of BTF type graph formed by candidate struct/union (we'll
+ * call it "candidate graph" in this description for brevity) to a type graph
+ * formed by (potential) canonical struct/union ("canonical graph" for brevity
+ * here, though keep in mind that not all types in canonical graph are
+ * necessarily canonical representatives themselves, some of them might be
+ * duplicates or its uniqueness might not have been established yet).
+ * Returns:
+ *  - >0, if type graphs are equivalent;
+ *  -  0, if not equivalent;
+ *  - <0, on error.
+ *
+ * Algorithm performs side-by-side DFS traversal of both type graphs and checks
+ * equivalence of BTF types at each step. If at any point BTF types in candidate
+ * and canonical graphs are not compatible structurally, whole graphs are
+ * incompatible. If types are structurally equivalent (i.e., all information
+ * except referenced type IDs is exactly the same), a mapping from `canon_id` to
+ * a `cand_id` is recoded in hypothetical mapping (`btf_dedup->hypot_map`).
+ * If a type references other types, then those referenced types are checked
+ * for equivalence recursively.
+ *
+ * During DFS traversal, if we find that for current `canon_id` type we
+ * already have some mapping in hypothetical map, we check for two possible
+ * situations:
+ *   - `canon_id` is mapped to exactly the same type as `cand_id`. This will
+ *     happen when type graphs have cycles. In this case we assume those two
+ *     types are equivalent.
+ *   - `canon_id` is mapped to different type. This is contradiction in our
+ *     hypothetical mapping, because same graph in canonical graph corresponds
+ *     to two different types in candidate graph, which for equivalent type
+ *     graphs shouldn't happen. This condition terminates equivalence check
+ *     with negative result.
+ *
+ * If type graphs traversal exhausts types to check and find no contradiction,
+ * then type graphs are equivalent.
+ *
+ * When checking types for equivalence, there is one special case: FWD types.
+ * If FWD type resolution is allowed and one of the types (either from canonical
+ * or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind
+ * flag) and their names match, hypothetical mapping is updated to point from
+ * FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully,
+ * this mapping will be used to record FWD -> STRUCT/UNION mapping permanently.
+ *
+ * Technically, this could lead to incorrect FWD to STRUCT/UNION resolution,
+ * if there are two exactly named (or anonymous) structs/unions that are
+ * compatible structurally, one of which has FWD field, while other is concrete
+ * STRUCT/UNION, but according to C sources they are different structs/unions
+ * that are referencing different types with the same name. This is extremely
+ * unlikely to happen, but btf_dedup API allows to disable FWD resolution if
+ * this logic is causing problems.
+ *
+ * Doing FWD resolution means that both candidate and/or canonical graphs can
+ * consists of portions of the graph that come from multiple compilation units.
+ * This is due to the fact that types within single compilation unit are always
+ * deduplicated and FWDs are already resolved, if referenced struct/union
+ * definition is available. So, if we had unresolved FWD and found corresponding
+ * STRUCT/UNION, they will be from different compilation units. This
+ * consequently means that when we "link" FWD to corresponding STRUCT/UNION,
+ * type graph will likely have at least two different BTF types that describe
+ * same type (e.g., most probably there will be two different BTF types for the
+ * same 'int' primitive type) and could even have "overlapping" parts of type
+ * graph that describe same subset of types.
+ *
+ * This in turn means that our assumption that each type in canonical graph
+ * must correspond to exactly one type in candidate graph might not hold
+ * anymore and will make it harder to detect contradictions using hypothetical
+ * map. To handle this problem, we allow to follow FWD -> STRUCT/UNION
+ * resolution only in canonical graph. FWDs in candidate graphs are never
+ * resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs
+ * that can occur:
+ *   - Both types in canonical and candidate graphs are FWDs. If they are
+ *     structurally equivalent, then they can either be both resolved to the
+ *     same STRUCT/UNION or not resolved at all. In both cases they are
+ *     equivalent and there is no need to resolve FWD on candidate side.
+ *   - Both types in canonical and candidate graphs are concrete STRUCT/UNION,
+ *     so nothing to resolve as well, algorithm will check equivalence anyway.
+ *   - Type in canonical graph is FWD, while type in candidate is concrete
+ *     STRUCT/UNION. In this case candidate graph comes from single compilation
+ *     unit, so there is exactly one BTF type for each unique C type. After
+ *     resolving FWD into STRUCT/UNION, there might be more than one BTF type
+ *     in canonical graph mapping to single BTF type in candidate graph, but
+ *     because hypothetical mapping maps from canonical to candidate types, it's
+ *     alright, and we still maintain the property of having single `canon_id`
+ *     mapping to single `cand_id` (there could be two different `canon_id`
+ *     mapped to the same `cand_id`, but it's not contradictory).
+ *   - Type in canonical graph is concrete STRUCT/UNION, while type in candidate
+ *     graph is FWD. In this case we are just going to check compatibility of
+ *     STRUCT/UNION and corresponding FWD, and if they are compatible, we'll
+ *     assume that whatever STRUCT/UNION FWD resolves to must be equivalent to
+ *     a concrete STRUCT/UNION from canonical graph. If the rest of type graphs
+ *     turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from
+ *     canonical graph.
+ */
+static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
+			      __u32 canon_id)
+{
+	struct btf_type *cand_type;
+	struct btf_type *canon_type;
+	__u32 hypot_type_id;
+	__u16 cand_kind;
+	__u16 canon_kind;
+	int i, eq;
+
+	/* if both resolve to the same canonical, they must be equivalent */
+	if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id))
+		return 1;
+
+	canon_id = resolve_fwd_id(d, canon_id);
+
+	hypot_type_id = d->hypot_map[canon_id];
+	if (hypot_type_id <= BTF_MAX_NR_TYPES) {
+		if (hypot_type_id == cand_id)
+			return 1;
+		/* In some cases compiler will generate different DWARF types
+		 * for *identical* array type definitions and use them for
+		 * different fields within the *same* struct. This breaks type
+		 * equivalence check, which makes an assumption that candidate
+		 * types sub-graph has a consistent and deduped-by-compiler
+		 * types within a single CU. And similar situation can happen
+		 * with struct/union sometimes, and event with pointers.
+		 * So accommodate cases like this doing a structural
+		 * comparison recursively, but avoiding being stuck in endless
+		 * loops by limiting the depth up to which we check.
+		 */
+		if (btf_dedup_identical_types(d, hypot_type_id, cand_id, 16))
+			return 1;
+		return 0;
+	}
+
+	if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
+		return -ENOMEM;
+
+	cand_type = btf_type_by_id(d->btf, cand_id);
+	canon_type = btf_type_by_id(d->btf, canon_id);
+	cand_kind = btf_kind(cand_type);
+	canon_kind = btf_kind(canon_type);
+
+	if (cand_type->name_off != canon_type->name_off)
+		return 0;
+
+	/* FWD <--> STRUCT/UNION equivalence check, if enabled */
+	if ((cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD)
+	    && cand_kind != canon_kind) {
+		__u16 real_kind;
+		__u16 fwd_kind;
+
+		if (cand_kind == BTF_KIND_FWD) {
+			real_kind = canon_kind;
+			fwd_kind = btf_fwd_kind(cand_type);
+		} else {
+			real_kind = cand_kind;
+			fwd_kind = btf_fwd_kind(canon_type);
+			/* we'd need to resolve base FWD to STRUCT/UNION */
+			if (fwd_kind == real_kind && canon_id < d->btf->start_id)
+				d->hypot_adjust_canon = true;
+		}
+		return fwd_kind == real_kind;
+	}
+
+	if (cand_kind != canon_kind)
+		return 0;
+
+	switch (cand_kind) {
+	case BTF_KIND_INT:
+		return btf_equal_int_tag(cand_type, canon_type);
+
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		return btf_compat_enum(cand_type, canon_type);
+
+	case BTF_KIND_FWD:
+	case BTF_KIND_FLOAT:
+		return btf_equal_common(cand_type, canon_type);
+
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_TYPE_TAG:
+		if (cand_type->info != canon_type->info)
+			return 0;
+		return btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
+
+	case BTF_KIND_ARRAY: {
+		const struct btf_array *cand_arr, *canon_arr;
+
+		if (!btf_compat_array(cand_type, canon_type))
+			return 0;
+		cand_arr = btf_array(cand_type);
+		canon_arr = btf_array(canon_type);
+		eq = btf_dedup_is_equiv(d, cand_arr->index_type, canon_arr->index_type);
+		if (eq <= 0)
+			return eq;
+		return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type);
+	}
+
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *cand_m, *canon_m;
+		__u32 vlen;
+
+		if (!btf_shallow_equal_struct(cand_type, canon_type))
+			return 0;
+		vlen = btf_vlen(cand_type);
+		cand_m = btf_members(cand_type);
+		canon_m = btf_members(canon_type);
+		for (i = 0; i < vlen; i++) {
+			eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type);
+			if (eq <= 0) {
+				if (cand_type->name_off) {
+					pr_debug("%s '%s' size=%u vlen=%u cand_id[%u] canon_id[%u] shallow-equal but not equiv for field#%d '%s': %d\n",
+						 cand_kind == BTF_KIND_STRUCT ? "STRUCT" : "UNION",
+						 btf__name_by_offset(d->btf, cand_type->name_off),
+						 cand_type->size, vlen, cand_id, canon_id, i,
+						 btf__name_by_offset(d->btf, cand_m->name_off), eq);
+				}
+				return eq;
+			}
+			cand_m++;
+			canon_m++;
+		}
+
+		return 1;
+	}
+
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *cand_p, *canon_p;
+		__u32 vlen;
+
+		if (!btf_compat_fnproto(cand_type, canon_type))
+			return 0;
+		eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
+		if (eq <= 0)
+			return eq;
+		vlen = btf_vlen(cand_type);
+		cand_p = btf_params(cand_type);
+		canon_p = btf_params(canon_type);
+		for (i = 0; i < vlen; i++) {
+			eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type);
+			if (eq <= 0)
+				return eq;
+			cand_p++;
+			canon_p++;
+		}
+		return 1;
+	}
+
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * Use hypothetical mapping, produced by successful type graph equivalence
+ * check, to augment existing struct/union canonical mapping, where possible.
+ *
+ * If BTF_KIND_FWD resolution is allowed, this mapping is also used to record
+ * FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional:
+ * it doesn't matter if FWD type was part of canonical graph or candidate one,
+ * we are recording the mapping anyway. As opposed to carefulness required
+ * for struct/union correspondence mapping (described below), for FWD resolution
+ * it's not important, as by the time that FWD type (reference type) will be
+ * deduplicated all structs/unions will be deduped already anyway.
+ *
+ * Recording STRUCT/UNION mapping is purely a performance optimization and is
+ * not required for correctness. It needs to be done carefully to ensure that
+ * struct/union from candidate's type graph is not mapped into corresponding
+ * struct/union from canonical type graph that itself hasn't been resolved into
+ * canonical representative. The only guarantee we have is that canonical
+ * struct/union was determined as canonical and that won't change. But any
+ * types referenced through that struct/union fields could have been not yet
+ * resolved, so in case like that it's too early to establish any kind of
+ * correspondence between structs/unions.
+ *
+ * No canonical correspondence is derived for primitive types (they are already
+ * deduplicated completely already anyway) or reference types (they rely on
+ * stability of struct/union canonical relationship for equivalence checks).
+ */
+static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
+{
+	__u32 canon_type_id, targ_type_id;
+	__u16 t_kind, c_kind;
+	__u32 t_id, c_id;
+	int i;
+
+	for (i = 0; i < d->hypot_cnt; i++) {
+		canon_type_id = d->hypot_list[i];
+		targ_type_id = d->hypot_map[canon_type_id];
+		t_id = resolve_type_id(d, targ_type_id);
+		c_id = resolve_type_id(d, canon_type_id);
+		t_kind = btf_kind(btf__type_by_id(d->btf, t_id));
+		c_kind = btf_kind(btf__type_by_id(d->btf, c_id));
+		/*
+		 * Resolve FWD into STRUCT/UNION.
+		 * It's ok to resolve FWD into STRUCT/UNION that's not yet
+		 * mapped to canonical representative (as opposed to
+		 * STRUCT/UNION <--> STRUCT/UNION mapping logic below), because
+		 * eventually that struct is going to be mapped and all resolved
+		 * FWDs will automatically resolve to correct canonical
+		 * representative. This will happen before ref type deduping,
+		 * which critically depends on stability of these mapping. This
+		 * stability is not a requirement for STRUCT/UNION equivalence
+		 * checks, though.
+		 */
+
+		/* if it's the split BTF case, we still need to point base FWD
+		 * to STRUCT/UNION in a split BTF, because FWDs from split BTF
+		 * will be resolved against base FWD. If we don't point base
+		 * canonical FWD to the resolved STRUCT/UNION, then all the
+		 * FWDs in split BTF won't be correctly resolved to a proper
+		 * STRUCT/UNION.
+		 */
+		if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD)
+			d->map[c_id] = t_id;
+
+		/* if graph equivalence determined that we'd need to adjust
+		 * base canonical types, then we need to only point base FWDs
+		 * to STRUCTs/UNIONs and do no more modifications. For all
+		 * other purposes the type graphs were not equivalent.
+		 */
+		if (d->hypot_adjust_canon)
+			continue;
+
+		if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
+			d->map[t_id] = c_id;
+
+		if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) &&
+		    c_kind != BTF_KIND_FWD &&
+		    is_type_mapped(d, c_id) &&
+		    !is_type_mapped(d, t_id)) {
+			/*
+			 * as a perf optimization, we can map struct/union
+			 * that's part of type graph we just verified for
+			 * equivalence. We can do that for struct/union that has
+			 * canonical representative only, though.
+			 */
+			d->map[t_id] = c_id;
+		}
+	}
+}
+
+static inline long btf_hash_by_kind(struct btf_type *t, __u16 kind)
+{
+	if (kind == BTF_KIND_TYPEDEF)
+		return btf_hash_typedef(t);
+	else
+		return btf_hash_struct(t);
+}
+
+static inline bool btf_equal_by_kind(struct btf_type *t1, struct btf_type *t2, __u16 kind)
+{
+	if (kind == BTF_KIND_TYPEDEF)
+		return btf_equal_typedef(t1, t2);
+	else
+		return btf_shallow_equal_struct(t1, t2);
+}
+
+/*
+ * Deduplicate struct/union and typedef types.
+ *
+ * For each struct/union type its type signature hash is calculated, taking
+ * into account type's name, size, number, order and names of fields, but
+ * ignoring type ID's referenced from fields, because they might not be deduped
+ * completely until after reference types deduplication phase. For each typedef
+ * type, the hash is computed based on the type’s name and size. This type hash
+ * is used to iterate over all potential canonical types, sharing same hash.
+ * For each canonical candidate we check whether type graphs that they form
+ * (through referenced types in fields and so on) are equivalent using algorithm
+ * implemented in `btf_dedup_is_equiv`. If such equivalence is found and
+ * BTF_KIND_FWD resolution is allowed, then hypothetical mapping
+ * (btf_dedup->hypot_map) produced by aforementioned type graph equivalence
+ * algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to
+ * potentially map other structs/unions to their canonical representatives,
+ * if such relationship hasn't yet been established. This speeds up algorithm
+ * by eliminating some of the duplicate work.
+ *
+ * If no matching canonical representative was found, struct/union is marked
+ * as canonical for itself and is added into btf_dedup->dedup_table hash map
+ * for further look ups.
+ */
+static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
+{
+	struct btf_type *cand_type, *t;
+	struct hashmap_entry *hash_entry;
+	/* if we don't find equivalent type, then we are canonical */
+	__u32 new_id = type_id;
+	__u16 kind;
+	long h;
+
+	/* already deduped or is in process of deduping (loop detected) */
+	if (d->map[type_id] <= BTF_MAX_NR_TYPES)
+		return 0;
+
+	t = btf_type_by_id(d->btf, type_id);
+	kind = btf_kind(t);
+
+	if (kind != BTF_KIND_STRUCT &&
+		kind != BTF_KIND_UNION &&
+		kind != BTF_KIND_TYPEDEF)
+		return 0;
+
+	h = btf_hash_by_kind(t, kind);
+	for_each_dedup_cand(d, hash_entry, h) {
+		__u32 cand_id = hash_entry->value;
+		int eq;
+
+		/*
+		 * Even though btf_dedup_is_equiv() checks for
+		 * btf_equal_by_kind() internally when checking two
+		 * structs (unions) or typedefs for equivalence, we need to guard here
+		 * from picking matching FWD type as a dedup candidate.
+		 * This can happen due to hash collision. In such case just
+		 * relying on btf_dedup_is_equiv() would lead to potentially
+		 * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
+		 * FWD and compatible STRUCT/UNION are considered equivalent.
+		 */
+		cand_type = btf_type_by_id(d->btf, cand_id);
+		if (!btf_equal_by_kind(t, cand_type, kind))
+			continue;
+
+		btf_dedup_clear_hypot_map(d);
+		eq = btf_dedup_is_equiv(d, type_id, cand_id);
+		if (eq < 0)
+			return eq;
+		if (!eq)
+			continue;
+		btf_dedup_merge_hypot_map(d);
+		if (d->hypot_adjust_canon) /* not really equivalent */
+			continue;
+		new_id = cand_id;
+		break;
+	}
+
+	d->map[type_id] = new_id;
+	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int btf_dedup_struct_types(struct btf_dedup *d)
+{
+	int i, err;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		err = btf_dedup_struct_type(d, d->btf->start_id + i);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/*
+ * Deduplicate reference type.
+ *
+ * Once all primitive, struct/union and typedef types got deduplicated, we can easily
+ * deduplicate all other (reference) BTF types. This is done in two steps:
+ *
+ * 1. Resolve all referenced type IDs into their canonical type IDs. This
+ * resolution can be done either immediately for primitive, struct/union, and typedef
+ * types (because they were deduped in previous two phases) or recursively for
+ * reference types. Recursion will always terminate at either primitive or
+ * struct/union and typedef types, at which point we can "unwind" chain of reference
+ * types one by one. There is no danger of encountering cycles in C, as the only way to
+ * form a type cycle is through struct or union types. Go can form such cycles through
+ * typedef. Thus, any chain of reference types, even those taking part in a type cycle,
+ * will inevitably reach a struct/union or typedef type at some point.
+ *
+ * 2. Once all referenced type IDs are resolved into canonical ones, BTF type
+ * becomes "stable", in the sense that no further deduplication will cause
+ * any changes to it. With that, it's now possible to calculate type's signature
+ * hash (this time taking into account referenced type IDs) and loop over all
+ * potential canonical representatives. If no match was found, current type
+ * will become canonical representative of itself and will be added into
+ * btf_dedup->dedup_table as another possible canonical representative.
+ */
+static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
+{
+	struct hashmap_entry *hash_entry;
+	__u32 new_id = type_id, cand_id;
+	struct btf_type *t, *cand;
+	/* if we don't find equivalent type, then we are representative type */
+	int ref_type_id;
+	long h;
+
+	if (d->map[type_id] == BTF_IN_PROGRESS_ID)
+		return -ELOOP;
+	if (d->map[type_id] <= BTF_MAX_NR_TYPES)
+		return resolve_type_id(d, type_id);
+
+	t = btf_type_by_id(d->btf, type_id);
+	d->map[type_id] = BTF_IN_PROGRESS_ID;
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_CONST:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_TYPE_TAG:
+		ref_type_id = btf_dedup_ref_type(d, t->type);
+		if (ref_type_id < 0)
+			return ref_type_id;
+		t->type = ref_type_id;
+
+		h = btf_hash_common(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_common(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+		}
+		break;
+
+	case BTF_KIND_DECL_TAG:
+		ref_type_id = btf_dedup_ref_type(d, t->type);
+		if (ref_type_id < 0)
+			return ref_type_id;
+		t->type = ref_type_id;
+
+		h = btf_hash_int_decl_tag(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_int_tag(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+		}
+		break;
+
+	case BTF_KIND_ARRAY: {
+		struct btf_array *info = btf_array(t);
+
+		ref_type_id = btf_dedup_ref_type(d, info->type);
+		if (ref_type_id < 0)
+			return ref_type_id;
+		info->type = ref_type_id;
+
+		ref_type_id = btf_dedup_ref_type(d, info->index_type);
+		if (ref_type_id < 0)
+			return ref_type_id;
+		info->index_type = ref_type_id;
+
+		h = btf_hash_array(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_array(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+		}
+		break;
+	}
+
+	case BTF_KIND_FUNC_PROTO: {
+		struct btf_param *param;
+		__u32 vlen;
+		int i;
+
+		ref_type_id = btf_dedup_ref_type(d, t->type);
+		if (ref_type_id < 0)
+			return ref_type_id;
+		t->type = ref_type_id;
+
+		vlen = btf_vlen(t);
+		param = btf_params(t);
+		for (i = 0; i < vlen; i++) {
+			ref_type_id = btf_dedup_ref_type(d, param->type);
+			if (ref_type_id < 0)
+				return ref_type_id;
+			param->type = ref_type_id;
+			param++;
+		}
+
+		h = btf_hash_fnproto(t);
+		for_each_dedup_cand(d, hash_entry, h) {
+			cand_id = hash_entry->value;
+			cand = btf_type_by_id(d->btf, cand_id);
+			if (btf_equal_fnproto(t, cand)) {
+				new_id = cand_id;
+				break;
+			}
+		}
+		break;
+	}
+
+	default:
+		return -EINVAL;
+	}
+
+	d->map[type_id] = new_id;
+	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
+		return -ENOMEM;
+
+	return new_id;
+}
+
+static int btf_dedup_ref_types(struct btf_dedup *d)
+{
+	int i, err;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		err = btf_dedup_ref_type(d, d->btf->start_id + i);
+		if (err < 0)
+			return err;
+	}
+	/* we won't need d->dedup_table anymore */
+	hashmap__free(d->dedup_table);
+	d->dedup_table = NULL;
+	return 0;
+}
+
+/*
+ * Collect a map from type names to type ids for all canonical structs
+ * and unions. If the same name is shared by several canonical types
+ * use a special value 0 to indicate this fact.
+ */
+static int btf_dedup_fill_unique_names_map(struct btf_dedup *d, struct hashmap *names_map)
+{
+	__u32 nr_types = btf__type_cnt(d->btf);
+	struct btf_type *t;
+	__u32 type_id;
+	__u16 kind;
+	int err;
+
+	/*
+	 * Iterate over base and split module ids in order to get all
+	 * available structs in the map.
+	 */
+	for (type_id = 1; type_id < nr_types; ++type_id) {
+		t = btf_type_by_id(d->btf, type_id);
+		kind = btf_kind(t);
+
+		if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
+			continue;
+
+		/* Skip non-canonical types */
+		if (type_id != d->map[type_id])
+			continue;
+
+		err = hashmap__add(names_map, t->name_off, type_id);
+		if (err == -EEXIST)
+			err = hashmap__set(names_map, t->name_off, 0, NULL, NULL);
+
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int btf_dedup_resolve_fwd(struct btf_dedup *d, struct hashmap *names_map, __u32 type_id)
+{
+	struct btf_type *t = btf_type_by_id(d->btf, type_id);
+	enum btf_fwd_kind fwd_kind = btf_kflag(t);
+	__u16 cand_kind, kind = btf_kind(t);
+	struct btf_type *cand_t;
+	uintptr_t cand_id;
+
+	if (kind != BTF_KIND_FWD)
+		return 0;
+
+	/* Skip if this FWD already has a mapping */
+	if (type_id != d->map[type_id])
+		return 0;
+
+	if (!hashmap__find(names_map, t->name_off, &cand_id))
+		return 0;
+
+	/* Zero is a special value indicating that name is not unique */
+	if (!cand_id)
+		return 0;
+
+	cand_t = btf_type_by_id(d->btf, cand_id);
+	cand_kind = btf_kind(cand_t);
+	if ((cand_kind == BTF_KIND_STRUCT && fwd_kind != BTF_FWD_STRUCT) ||
+	    (cand_kind == BTF_KIND_UNION && fwd_kind != BTF_FWD_UNION))
+		return 0;
+
+	d->map[type_id] = cand_id;
+
+	return 0;
+}
+
+/*
+ * Resolve unambiguous forward declarations.
+ *
+ * The lion's share of all FWD declarations is resolved during
+ * `btf_dedup_struct_types` phase when different type graphs are
+ * compared against each other. However, if in some compilation unit a
+ * FWD declaration is not a part of a type graph compared against
+ * another type graph that declaration's canonical type would not be
+ * changed. Example:
+ *
+ * CU #1:
+ *
+ * struct foo;
+ * struct foo *some_global;
+ *
+ * CU #2:
+ *
+ * struct foo { int u; };
+ * struct foo *another_global;
+ *
+ * After `btf_dedup_struct_types` the BTF looks as follows:
+ *
+ * [1] STRUCT 'foo' size=4 vlen=1 ...
+ * [2] INT 'int' size=4 ...
+ * [3] PTR '(anon)' type_id=1
+ * [4] FWD 'foo' fwd_kind=struct
+ * [5] PTR '(anon)' type_id=4
+ *
+ * This pass assumes that such FWD declarations should be mapped to
+ * structs or unions with identical name in case if the name is not
+ * ambiguous.
+ */
+static int btf_dedup_resolve_fwds(struct btf_dedup *d)
+{
+	int i, err;
+	struct hashmap *names_map;
+
+	names_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL);
+	if (IS_ERR(names_map))
+		return PTR_ERR(names_map);
+
+	err = btf_dedup_fill_unique_names_map(d, names_map);
+	if (err < 0)
+		goto exit;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		err = btf_dedup_resolve_fwd(d, names_map, d->btf->start_id + i);
+		if (err < 0)
+			break;
+	}
+
+exit:
+	hashmap__free(names_map);
+	return err;
+}
+
+/*
+ * Compact types.
+ *
+ * After we established for each type its corresponding canonical representative
+ * type, we now can eliminate types that are not canonical and leave only
+ * canonical ones layed out sequentially in memory by copying them over
+ * duplicates. During compaction btf_dedup->hypot_map array is reused to store
+ * a map from original type ID to a new compacted type ID, which will be used
+ * during next phase to "fix up" type IDs, referenced from struct/union and
+ * reference types.
+ */
+static int btf_dedup_compact_types(struct btf_dedup *d)
+{
+	__u32 *new_offs;
+	__u32 next_type_id = d->btf->start_id;
+	const struct btf_type *t;
+	void *p;
+	int i, id, len;
+
+	/* we are going to reuse hypot_map to store compaction remapping */
+	d->hypot_map[0] = 0;
+	/* base BTF types are not renumbered */
+	for (id = 1; id < d->btf->start_id; id++)
+		d->hypot_map[id] = id;
+	for (i = 0, id = d->btf->start_id; i < d->btf->nr_types; i++, id++)
+		d->hypot_map[id] = BTF_UNPROCESSED_ID;
+
+	p = d->btf->types_data;
+
+	for (i = 0, id = d->btf->start_id; i < d->btf->nr_types; i++, id++) {
+		if (d->map[id] != id)
+			continue;
+
+		t = btf__type_by_id(d->btf, id);
+		len = btf_type_size(d->btf, t);
+		if (len < 0)
+			return len;
+
+		memmove(p, t, len);
+		d->hypot_map[id] = next_type_id;
+		d->btf->type_offs[next_type_id - d->btf->start_id] = p - d->btf->types_data;
+		p += len;
+		next_type_id++;
+	}
+
+	/* shrink struct btf's internal types index and update btf_header */
+	d->btf->nr_types = next_type_id - d->btf->start_id;
+	d->btf->type_offs_cap = d->btf->nr_types;
+	d->btf->hdr.type_len = p - d->btf->types_data;
+	new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap,
+				       sizeof(*new_offs));
+	if (d->btf->type_offs_cap && !new_offs)
+		return -ENOMEM;
+	d->btf->type_offs = new_offs;
+	if (d->btf->layout)
+		d->btf->hdr.layout_off = d->btf->hdr.type_off + d->btf->hdr.type_len;
+	d->btf->hdr.str_off = d->btf->hdr.type_off + d->btf->hdr.type_len + d->btf->hdr.layout_len;
+	d->btf->raw_size = d->btf->hdr.hdr_len + d->btf->hdr.type_off + d->btf->hdr.type_len +
+			   d->btf->hdr.layout_len + d->btf->hdr.str_len;
+	return 0;
+}
+
+/*
+ * Figure out final (deduplicated and compacted) type ID for provided original
+ * `type_id` by first resolving it into corresponding canonical type ID and
+ * then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map,
+ * which is populated during compaction phase.
+ */
+static int btf_dedup_remap_type_id(__u32 *type_id, void *ctx)
+{
+	struct btf_dedup *d = ctx;
+	__u32 resolved_type_id, new_type_id;
+
+	resolved_type_id = resolve_type_id(d, *type_id);
+	new_type_id = d->hypot_map[resolved_type_id];
+	if (new_type_id > BTF_MAX_NR_TYPES)
+		return -EINVAL;
+
+	*type_id = new_type_id;
+	return 0;
+}
+
+/*
+ * Remap referenced type IDs into deduped type IDs.
+ *
+ * After BTF types are deduplicated and compacted, their final type IDs may
+ * differ from original ones. The map from original to a corresponding
+ * deduped type ID is stored in btf_dedup->hypot_map and is populated during
+ * compaction phase. During remapping phase we are rewriting all type IDs
+ * referenced from any BTF type (e.g., struct fields, func proto args, etc) to
+ * their final deduped type IDs.
+ */
+static int btf_dedup_remap_types(struct btf_dedup *d)
+{
+	int i, r;
+
+	for (i = 0; i < d->btf->nr_types; i++) {
+		struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i);
+		struct btf_field_iter it;
+		__u32 *type_id;
+
+		r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);
+		if (r)
+			return r;
+
+		while ((type_id = btf_field_iter_next(&it))) {
+			__u32 resolved_id, new_id;
+
+			resolved_id = resolve_type_id(d, *type_id);
+			new_id = d->hypot_map[resolved_id];
+			if (new_id > BTF_MAX_NR_TYPES)
+				return -EINVAL;
+
+			*type_id = new_id;
+		}
+	}
+
+	if (!d->btf_ext)
+		return 0;
+
+	r = btf_ext_visit_type_ids(d->btf_ext, btf_dedup_remap_type_id, d);
+	if (r)
+		return r;
+
+	return 0;
+}
+
+/*
+ * Probe few well-known locations for vmlinux kernel image and try to load BTF
+ * data out of it to use for target BTF.
+ */
+struct btf *btf__load_vmlinux_btf(void)
+{
+	const char *sysfs_btf_path = "/sys/kernel/btf/vmlinux";
+	/* fall back locations, trying to find vmlinux on disk */
+	const char *locations[] = {
+		"/boot/vmlinux-%1$s",
+		"/lib/modules/%1$s/vmlinux-%1$s",
+		"/lib/modules/%1$s/build/vmlinux",
+		"/usr/lib/modules/%1$s/kernel/vmlinux",
+		"/usr/lib/debug/boot/vmlinux-%1$s",
+		"/usr/lib/debug/boot/vmlinux-%1$s.debug",
+		"/usr/lib/debug/lib/modules/%1$s/vmlinux",
+	};
+	char path[PATH_MAX + 1];
+	struct utsname buf;
+	struct btf *btf;
+	int i, err;
+
+	/* is canonical sysfs location accessible? */
+	if (faccessat(AT_FDCWD, sysfs_btf_path, F_OK, AT_EACCESS) < 0) {
+		pr_warn("kernel BTF is missing at '%s', was CONFIG_DEBUG_INFO_BTF enabled?\n",
+			sysfs_btf_path);
+	} else {
+		btf = btf_parse_raw_mmap(sysfs_btf_path, NULL);
+		if (IS_ERR(btf))
+			btf = btf__parse(sysfs_btf_path, NULL);
+
+		if (!btf) {
+			err = -errno;
+			pr_warn("failed to read kernel BTF from '%s': %s\n",
+				sysfs_btf_path, errstr(err));
+			return libbpf_err_ptr(err);
+		}
+		pr_debug("loaded kernel BTF from '%s'\n", sysfs_btf_path);
+		return btf;
+	}
+
+	/* try fallback locations */
+	uname(&buf);
+	for (i = 0; i < ARRAY_SIZE(locations); i++) {
+		snprintf(path, PATH_MAX, locations[i], buf.release);
+
+		if (faccessat(AT_FDCWD, path, R_OK, AT_EACCESS))
+			continue;
+
+		btf = btf__parse(path, NULL);
+		err = libbpf_get_error(btf);
+		pr_debug("loading kernel BTF '%s': %s\n", path, errstr(err));
+		if (err)
+			continue;
+
+		return btf;
+	}
+
+	pr_warn("failed to find valid kernel BTF\n");
+	return libbpf_err_ptr(-ESRCH);
+}
+
+struct btf *libbpf_find_kernel_btf(void) __attribute__((alias("btf__load_vmlinux_btf")));
+
+struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf)
+{
+	char path[80];
+
+	snprintf(path, sizeof(path), "/sys/kernel/btf/%s", module_name);
+	return btf__parse_split(path, vmlinux_btf);
+}
+
+int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx)
+{
+	const struct btf_ext_info *seg;
+	struct btf_ext_info_sec *sec;
+	int i, err;
+
+	seg = &btf_ext->func_info;
+	for_each_btf_ext_sec(seg, sec) {
+		struct bpf_func_info_min *rec;
+
+		for_each_btf_ext_rec(seg, sec, i, rec) {
+			err = visit(&rec->type_id, ctx);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	seg = &btf_ext->core_relo_info;
+	for_each_btf_ext_sec(seg, sec) {
+		struct bpf_core_relo *rec;
+
+		for_each_btf_ext_rec(seg, sec, i, rec) {
+			err = visit(&rec->type_id, ctx);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx)
+{
+	const struct btf_ext_info *seg;
+	struct btf_ext_info_sec *sec;
+	int i, err;
+
+	seg = &btf_ext->func_info;
+	for_each_btf_ext_sec(seg, sec) {
+		err = visit(&sec->sec_name_off, ctx);
+		if (err)
+			return err;
+	}
+
+	seg = &btf_ext->line_info;
+	for_each_btf_ext_sec(seg, sec) {
+		struct bpf_line_info_min *rec;
+
+		err = visit(&sec->sec_name_off, ctx);
+		if (err)
+			return err;
+
+		for_each_btf_ext_rec(seg, sec, i, rec) {
+			err = visit(&rec->file_name_off, ctx);
+			if (err)
+				return err;
+			err = visit(&rec->line_off, ctx);
+			if (err)
+				return err;
+		}
+	}
+
+	seg = &btf_ext->core_relo_info;
+	for_each_btf_ext_sec(seg, sec) {
+		struct bpf_core_relo *rec;
+
+		err = visit(&sec->sec_name_off, ctx);
+		if (err)
+			return err;
+
+		for_each_btf_ext_rec(seg, sec, i, rec) {
+			err = visit(&rec->access_str_off, ctx);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+struct btf_distill {
+	struct btf_pipe pipe;
+	int *id_map;
+	unsigned int split_start_id;
+	unsigned int split_start_str;
+	int diff_id;
+};
+
+static int btf_add_distilled_type_ids(struct btf_distill *dist, __u32 i)
+{
+	struct btf_type *split_t = btf_type_by_id(dist->pipe.src, i);
+	struct btf_field_iter it;
+	__u32 *id;
+	int err;
+
+	err = btf_field_iter_init(&it, split_t, BTF_FIELD_ITER_IDS);
+	if (err)
+		return err;
+	while ((id = btf_field_iter_next(&it))) {
+		struct btf_type *base_t;
+
+		if (!*id)
+			continue;
+		/* split BTF id, not needed */
+		if (*id >= dist->split_start_id)
+			continue;
+		/* already added ? */
+		if (dist->id_map[*id] > 0)
+			continue;
+
+		/* only a subset of base BTF types should be referenced from
+		 * split BTF; ensure nothing unexpected is referenced.
+		 */
+		base_t = btf_type_by_id(dist->pipe.src, *id);
+		switch (btf_kind(base_t)) {
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_FWD:
+		case BTF_KIND_ARRAY:
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+		case BTF_KIND_PTR:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_FUNC_PROTO:
+		case BTF_KIND_TYPE_TAG:
+			dist->id_map[*id] = *id;
+			break;
+		default:
+			pr_warn("unexpected reference to base type[%u] of kind [%u] when creating distilled base BTF.\n",
+				*id, btf_kind(base_t));
+			return -EINVAL;
+		}
+		/* If a base type is used, ensure types it refers to are
+		 * marked as used also; so for example if we find a PTR to INT
+		 * we need both the PTR and INT.
+		 *
+		 * The only exception is named struct/unions, since distilled
+		 * base BTF composite types have no members.
+		 */
+		if (btf_is_composite(base_t) && base_t->name_off)
+			continue;
+		err = btf_add_distilled_type_ids(dist, *id);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int btf_add_distilled_types(struct btf_distill *dist)
+{
+	bool adding_to_base = dist->pipe.dst->start_id == 1;
+	int id = btf__type_cnt(dist->pipe.dst);
+	struct btf_type *t;
+	int i, err = 0;
+
+
+	/* Add types for each of the required references to either distilled
+	 * base or split BTF, depending on type characteristics.
+	 */
+	for (i = 1; i < dist->split_start_id; i++) {
+		const char *name;
+		int kind;
+
+		if (!dist->id_map[i])
+			continue;
+		t = btf_type_by_id(dist->pipe.src, i);
+		kind = btf_kind(t);
+		name = btf__name_by_offset(dist->pipe.src, t->name_off);
+
+		switch (kind) {
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_FWD:
+			/* Named int, float, fwd are added to base. */
+			if (!adding_to_base)
+				continue;
+			err = btf_add_type(&dist->pipe, t);
+			break;
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			/* Named struct/union are added to base as 0-vlen
+			 * struct/union of same size.  Anonymous struct/unions
+			 * are added to split BTF as-is.
+			 */
+			if (adding_to_base) {
+				if (!t->name_off)
+					continue;
+				err = btf_add_composite(dist->pipe.dst, kind, name, t->size);
+			} else {
+				if (t->name_off)
+					continue;
+				err = btf_add_type(&dist->pipe, t);
+			}
+			break;
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+			/* Named enum[64]s are added to base as a sized
+			 * enum; relocation will match with appropriately-named
+			 * and sized enum or enum64.
+			 *
+			 * Anonymous enums are added to split BTF as-is.
+			 */
+			if (adding_to_base) {
+				if (!t->name_off)
+					continue;
+				err = btf__add_enum(dist->pipe.dst, name, t->size);
+			} else {
+				if (t->name_off)
+					continue;
+				err = btf_add_type(&dist->pipe, t);
+			}
+			break;
+		case BTF_KIND_ARRAY:
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_PTR:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_FUNC_PROTO:
+		case BTF_KIND_TYPE_TAG:
+			/* All other types are added to split BTF. */
+			if (adding_to_base)
+				continue;
+			err = btf_add_type(&dist->pipe, t);
+			break;
+		default:
+			pr_warn("unexpected kind when adding base type '%s'[%d] of kind [%d] to distilled base BTF.\n",
+				name, i, kind);
+			return -EINVAL;
+
+		}
+		if (err < 0)
+			break;
+		dist->id_map[i] = id++;
+	}
+	return err;
+}
+
+/* Split BTF ids without a mapping will be shifted downwards since distilled
+ * base BTF is smaller than the original base BTF.  For those that have a
+ * mapping (either to base or updated split BTF), update the id based on
+ * that mapping.
+ */
+static int btf_update_distilled_type_ids(struct btf_distill *dist, __u32 i)
+{
+	struct btf_type *t = btf_type_by_id(dist->pipe.dst, i);
+	struct btf_field_iter it;
+	__u32 *id;
+	int err;
+
+	err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);
+	if (err)
+		return err;
+	while ((id = btf_field_iter_next(&it))) {
+		if (dist->id_map[*id])
+			*id = dist->id_map[*id];
+		else if (*id >= dist->split_start_id)
+			*id -= dist->diff_id;
+	}
+	return 0;
+}
+
+/* Create updated split BTF with distilled base BTF; distilled base BTF
+ * consists of BTF information required to clarify the types that split
+ * BTF refers to, omitting unneeded details.  Specifically it will contain
+ * base types and memberless definitions of named structs, unions and enumerated
+ * types. Associated reference types like pointers, arrays and anonymous
+ * structs, unions and enumerated types will be added to split BTF.
+ * Size is recorded for named struct/unions to help guide matching to the
+ * target base BTF during later relocation.
+ *
+ * The only case where structs, unions or enumerated types are fully represented
+ * is when they are anonymous; in such cases, the anonymous type is added to
+ * split BTF in full.
+ *
+ * We return newly-created split BTF where the split BTF refers to a newly-created
+ * distilled base BTF. Both must be freed separately by the caller.
+ */
+int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf,
+		      struct btf **new_split_btf)
+{
+	struct btf *new_base = NULL, *new_split = NULL;
+	const struct btf *old_base;
+	unsigned int n = btf__type_cnt(src_btf);
+	struct btf_distill dist = {};
+	struct btf_type *t;
+	int i, err = 0;
+
+	/* src BTF must be split BTF. */
+	old_base = btf__base_btf(src_btf);
+	if (!new_base_btf || !new_split_btf || !old_base)
+		return libbpf_err(-EINVAL);
+
+	new_base = btf__new_empty();
+	if (!new_base)
+		return libbpf_err(-ENOMEM);
+
+	btf__set_endianness(new_base, btf__endianness(src_btf));
+
+	dist.id_map = calloc(n, sizeof(*dist.id_map));
+	if (!dist.id_map) {
+		err = -ENOMEM;
+		goto done;
+	}
+	dist.pipe.src = src_btf;
+	dist.pipe.dst = new_base;
+	dist.pipe.str_off_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL);
+	if (IS_ERR(dist.pipe.str_off_map)) {
+		err = -ENOMEM;
+		goto done;
+	}
+	dist.split_start_id = btf__type_cnt(old_base);
+	dist.split_start_str = old_base->hdr.str_len;
+
+	/* Pass over src split BTF; generate the list of base BTF type ids it
+	 * references; these will constitute our distilled BTF set to be
+	 * distributed over base and split BTF as appropriate.
+	 */
+	for (i = src_btf->start_id; i < n; i++) {
+		err = btf_add_distilled_type_ids(&dist, i);
+		if (err < 0)
+			goto done;
+	}
+	/* Next add types for each of the required references to base BTF and split BTF
+	 * in turn.
+	 */
+	err = btf_add_distilled_types(&dist);
+	if (err < 0)
+		goto done;
+
+	/* Create new split BTF with distilled base BTF as its base; the final
+	 * state is split BTF with distilled base BTF that represents enough
+	 * about its base references to allow it to be relocated with the base
+	 * BTF available.
+	 */
+	new_split = btf__new_empty_split(new_base);
+	if (!new_split) {
+		err = -errno;
+		goto done;
+	}
+	dist.pipe.dst = new_split;
+	/* First add all split types */
+	for (i = src_btf->start_id; i < n; i++) {
+		t = btf_type_by_id(src_btf, i);
+		err = btf_add_type(&dist.pipe, t);
+		if (err < 0)
+			goto done;
+	}
+	/* Now add distilled types to split BTF that are not added to base. */
+	err = btf_add_distilled_types(&dist);
+	if (err < 0)
+		goto done;
+
+	/* All split BTF ids will be shifted downwards since there are less base
+	 * BTF ids in distilled base BTF.
+	 */
+	dist.diff_id = dist.split_start_id - btf__type_cnt(new_base);
+
+	n = btf__type_cnt(new_split);
+	/* Now update base/split BTF ids. */
+	for (i = 1; i < n; i++) {
+		err = btf_update_distilled_type_ids(&dist, i);
+		if (err < 0)
+			break;
+	}
+done:
+	free(dist.id_map);
+	hashmap__free(dist.pipe.str_off_map);
+	if (err) {
+		btf__free(new_split);
+		btf__free(new_base);
+		return libbpf_err(err);
+	}
+	*new_base_btf = new_base;
+	*new_split_btf = new_split;
+
+	return 0;
+}
+
+const struct btf_header *btf_header(const struct btf *btf)
+{
+	return &btf->hdr;
+}
+
+void btf_set_base_btf(struct btf *btf, const struct btf *base_btf)
+{
+	btf->base_btf = (struct btf *)base_btf;
+	btf->start_id = btf__type_cnt(base_btf);
+	btf->start_str_off = base_btf->hdr.str_len + base_btf->start_str_off;
+}
+
+int btf__relocate(struct btf *btf, const struct btf *base_btf)
+{
+	int err = btf_relocate(btf, base_btf, NULL);
+
+	if (!err)
+		btf->owns_base = false;
+	return libbpf_err(err);
+}
+
+struct btf_permute {
+	struct btf *btf;
+	__u32 *id_map;
+	__u32 start_offs;
+};
+
+/* Callback function to remap individual type ID references */
+static int btf_permute_remap_type_id(__u32 *type_id, void *ctx)
+{
+	struct btf_permute *p = ctx;
+	__u32 new_id = *type_id;
+
+	/* refer to the base BTF or VOID type */
+	if (new_id < p->btf->start_id)
+		return 0;
+
+	if (new_id >= btf__type_cnt(p->btf))
+		return -EINVAL;
+
+	*type_id = p->id_map[new_id - p->btf->start_id + p->start_offs];
+	return 0;
+}
+
+int btf__permute(struct btf *btf, __u32 *id_map, __u32 id_map_cnt,
+		 const struct btf_permute_opts *opts)
+{
+	struct btf_permute p;
+	struct btf_ext *btf_ext;
+	void *nt, *new_types = NULL;
+	__u32 *order_map = NULL;
+	int err = 0, i;
+	__u32 n, id, start_offs = 0;
+
+	if (!OPTS_VALID(opts, btf_permute_opts))
+		return libbpf_err(-EINVAL);
+
+	if (btf__base_btf(btf)) {
+		n = btf->nr_types;
+	} else {
+		if (id_map[0] != 0)
+			return libbpf_err(-EINVAL);
+		n = btf__type_cnt(btf);
+		start_offs = 1;
+	}
+
+	if (id_map_cnt != n)
+		return libbpf_err(-EINVAL);
+
+	/* record the sequence of types */
+	order_map = calloc(id_map_cnt, sizeof(*id_map));
+	if (!order_map) {
+		err = -ENOMEM;
+		goto done;
+	}
+
+	new_types = calloc(btf->hdr.type_len, 1);
+	if (!new_types) {
+		err = -ENOMEM;
+		goto done;
+	}
+
+	err = btf_ensure_modifiable(btf);
+	if (err)
+		goto done;
+
+	for (i = start_offs; i < id_map_cnt; i++) {
+		id = id_map[i];
+		if (id < btf->start_id || id >= btf__type_cnt(btf)) {
+			err = -EINVAL;
+			goto done;
+		}
+		id -= btf->start_id - start_offs;
+		/* cannot be mapped to the same ID */
+		if (order_map[id]) {
+			err = -EINVAL;
+			goto done;
+		}
+		order_map[id] = i + btf->start_id - start_offs;
+	}
+
+	p.btf = btf;
+	p.id_map = id_map;
+	p.start_offs = start_offs;
+	nt = new_types;
+	for (i = start_offs; i < id_map_cnt; i++) {
+		struct btf_field_iter it;
+		const struct btf_type *t;
+		__u32 *type_id;
+		int type_size;
+
+		id = order_map[i];
+		t = btf__type_by_id(btf, id);
+		type_size = btf_type_size(btf, t);
+		memcpy(nt, t, type_size);
+
+		/* fix up referenced IDs for BTF */
+		err = btf_field_iter_init(&it, nt, BTF_FIELD_ITER_IDS);
+		if (err)
+			goto done;
+		while ((type_id = btf_field_iter_next(&it))) {
+			err = btf_permute_remap_type_id(type_id, &p);
+			if (err)
+				goto done;
+		}
+
+		nt += type_size;
+	}
+
+	/* fix up referenced IDs for btf_ext */
+	btf_ext = OPTS_GET(opts, btf_ext, NULL);
+	if (btf_ext) {
+		err = btf_ext_visit_type_ids(btf_ext, btf_permute_remap_type_id, &p);
+		if (err)
+			goto done;
+	}
+
+	for (nt = new_types, i = 0; i < id_map_cnt - start_offs; i++) {
+		btf->type_offs[i] = nt - new_types;
+		nt += btf_type_size(btf, nt);
+	}
+
+	free(order_map);
+	free(btf->types_data);
+	btf->types_data = new_types;
+	return 0;
+
+done:
+	free(order_map);
+	free(new_types);
+	return libbpf_err(err);
+}
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
new file mode 100644
index 000000000..587172c0d
--- /dev/null
+++ b/tools/lib/bpf/btf.h
@@ -0,0 +1,690 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (c) 2018 Facebook */
+/*! \file */
+
+#ifndef __LIBBPF_BTF_H
+#define __LIBBPF_BTF_H
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <linux/btf.h>
+#include <linux/types.h>
+
+#include "libbpf_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define BTF_ELF_SEC ".BTF"
+#define BTF_EXT_ELF_SEC ".BTF.ext"
+#define BTF_BASE_ELF_SEC ".BTF.base"
+#define MAPS_ELF_SEC ".maps"
+
+struct btf;
+struct btf_ext;
+struct btf_type;
+
+struct bpf_object;
+
+enum btf_endianness {
+	BTF_LITTLE_ENDIAN = 0,
+	BTF_BIG_ENDIAN = 1,
+};
+
+/**
+ * @brief **btf__free()** frees all data of a BTF object
+ * @param btf BTF object to free
+ */
+LIBBPF_API void btf__free(struct btf *btf);
+
+/**
+ * @brief **btf__new()** creates a new instance of a BTF object from the raw
+ * bytes of an ELF's BTF section
+ * @param data raw bytes
+ * @param size number of bytes passed in `data`
+ * @return new BTF object instance which has to be eventually freed with
+ * **btf__free()**
+ *
+ * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
+ * error code from such a pointer `libbpf_get_error()` should be used. If
+ * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
+ * returned on error instead. In both cases thread-local `errno` variable is
+ * always set to error code as well.
+ */
+LIBBPF_API struct btf *btf__new(const void *data, __u32 size);
+
+/**
+ * @brief **btf__new_split()** create a new instance of a BTF object from the
+ * provided raw data bytes. It takes another BTF instance, **base_btf**, which
+ * serves as a base BTF, which is extended by types in a newly created BTF
+ * instance
+ * @param data raw bytes
+ * @param size length of raw bytes
+ * @param base_btf the base BTF object
+ * @return new BTF object instance which has to be eventually freed with
+ * **btf__free()**
+ *
+ * If *base_btf* is NULL, `btf__new_split()` is equivalent to `btf__new()` and
+ * creates non-split BTF.
+ *
+ * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
+ * error code from such a pointer `libbpf_get_error()` should be used. If
+ * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
+ * returned on error instead. In both cases thread-local `errno` variable is
+ * always set to error code as well.
+ */
+LIBBPF_API struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf);
+
+/**
+ * @brief **btf__new_empty()** creates an empty BTF object.  Use
+ * `btf__add_*()` to populate such BTF object.
+ * @return new BTF object instance which has to be eventually freed with
+ * **btf__free()**
+ *
+ * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
+ * error code from such a pointer `libbpf_get_error()` should be used. If
+ * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
+ * returned on error instead. In both cases thread-local `errno` variable is
+ * always set to error code as well.
+ */
+LIBBPF_API struct btf *btf__new_empty(void);
+
+/**
+ * @brief **btf__new_empty_split()** creates an unpopulated BTF object from an
+ * ELF BTF section except with a base BTF on top of which split BTF should be
+ * based
+ * @param base_btf base BTF object
+ * @return new BTF object instance which has to be eventually freed with
+ * **btf__free()**
+ *
+ * If *base_btf* is NULL, `btf__new_empty_split()` is equivalent to
+ * `btf__new_empty()` and creates non-split BTF.
+ *
+ * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
+ * error code from such a pointer `libbpf_get_error()` should be used. If
+ * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
+ * returned on error instead. In both cases thread-local `errno` variable is
+ * always set to error code as well.
+ */
+LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf);
+
+struct btf_new_opts {
+	size_t sz;
+	struct btf *base_btf;	/* optional base BTF */
+	bool add_layout;	/* add BTF layout information */
+	size_t:0;
+};
+#define btf_new_opts__last_field add_layout
+
+/**
+ * @brief **btf__new_empty_opts()** creates an unpopulated BTF object with
+ * optional *base_btf* and BTF kind layout description if *add_layout*
+ * is set
+ * @return new BTF object instance which has to be eventually freed with
+ * **btf__free()**
+ *
+ * On error, NULL is returned and the thread-local `errno` variable is
+ * set to the error code.
+ */
+LIBBPF_API struct btf *btf__new_empty_opts(struct btf_new_opts *opts);
+
+/**
+ * @brief **btf__distill_base()** creates new versions of the split BTF
+ * *src_btf* and its base BTF. The new base BTF will only contain the types
+ * needed to improve robustness of the split BTF to small changes in base BTF.
+ * When that split BTF is loaded against a (possibly changed) base, this
+ * distilled base BTF will help update references to that (possibly changed)
+ * base BTF.
+ * @param src_btf source split BTF object
+ * @param new_base_btf pointer to where the new base BTF object pointer will be stored
+ * @param new_split_btf pointer to where the new split BTF object pointer will be stored
+ * @return 0 on success; negative error code, otherwise
+ *
+ * Both the new split and its associated new base BTF must be freed by
+ * the caller.
+ *
+ * If successful, 0 is returned and **new_base_btf** and **new_split_btf**
+ * will point at new base/split BTF. Both the new split and its associated
+ * new base BTF must be freed by the caller.
+ *
+ * A negative value is returned on error and the thread-local `errno` variable
+ * is set to the error code as well.
+ */
+LIBBPF_API int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf,
+				 struct btf **new_split_btf);
+
+LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
+LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf);
+LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
+LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf);
+LIBBPF_API struct btf *btf__parse_raw(const char *path);
+LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
+
+LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
+LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
+
+LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
+LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
+
+LIBBPF_API int btf__load_into_kernel(struct btf *btf);
+LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
+				   const char *type_name);
+LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
+					const char *type_name, __u32 kind);
+LIBBPF_API __s32 btf__find_by_name_kind_own(const struct btf *btf,
+					    const char *type_name, __u32 kind);
+LIBBPF_API __u32 btf__type_cnt(const struct btf *btf);
+LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf);
+LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
+						  __u32 id);
+LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
+LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
+LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf);
+LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian);
+LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
+LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
+LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
+LIBBPF_API int btf__fd(const struct btf *btf);
+LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
+LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size);
+LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
+LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
+
+LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
+LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
+LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
+LIBBPF_API enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext);
+LIBBPF_API int btf_ext__set_endianness(struct btf_ext *btf_ext,
+				       enum btf_endianness endian);
+
+LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
+LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
+LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
+			     const struct btf_type *src_type);
+/**
+ * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf*
+ * @param btf BTF object which all the BTF types and strings are added to
+ * @param src_btf BTF object which all BTF types and referenced strings are copied from
+ * @return BTF type ID of the first appended BTF type, or negative error code
+ *
+ * **btf__add_btf()** can be used to simply and efficiently append the entire
+ * contents of one BTF object to another one. All the BTF type data is copied
+ * over, all referenced type IDs are adjusted by adding a necessary ID offset.
+ * Only strings referenced from BTF types are copied over and deduplicated, so
+ * if there were some unused strings in *src_btf*, those won't be copied over,
+ * which is consistent with the general string deduplication semantics of BTF
+ * writing APIs.
+ *
+ * If any error is encountered during this process, the contents of *btf* is
+ * left intact, which means that **btf__add_btf()** follows the transactional
+ * semantics and the operation as a whole is all-or-nothing.
+ *
+ * *src_btf* has to be non-split BTF, as of now copying types from split BTF
+ * is not supported and will result in -ENOTSUP error code returned.
+ */
+LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf);
+
+LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
+LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);
+LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id);
+LIBBPF_API int btf__add_array(struct btf *btf,
+			      int index_type_id, int elem_type_id, __u32 nr_elems);
+/* struct/union construction APIs */
+LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz);
+LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz);
+LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id,
+			      __u32 bit_offset, __u32 bit_size);
+
+/* enum construction APIs */
+LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);
+LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);
+LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);
+LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);
+
+enum btf_fwd_kind {
+	BTF_FWD_STRUCT = 0,
+	BTF_FWD_UNION = 1,
+	BTF_FWD_ENUM = 2,
+};
+
+LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind);
+LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
+LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
+LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
+LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
+LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
+LIBBPF_API int btf__add_type_attr(struct btf *btf, const char *value, int ref_type_id);
+
+/* func and func_proto construction APIs */
+LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
+			     enum btf_func_linkage linkage, int proto_type_id);
+LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id);
+LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id);
+
+/* var & datasec construction APIs */
+LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id);
+LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz);
+LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
+					 __u32 offset, __u32 byte_sz);
+
+/* tag construction API */
+LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
+			    int component_idx);
+LIBBPF_API int btf__add_decl_attr(struct btf *btf, const char *value, int ref_type_id,
+				  int component_idx);
+
+struct btf_dedup_opts {
+	size_t sz;
+	/* optional .BTF.ext info to dedup along the main BTF info */
+	struct btf_ext *btf_ext;
+	/* force hash collisions (used for testing) */
+	bool force_collisions;
+	size_t :0;
+};
+#define btf_dedup_opts__last_field force_collisions
+
+LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts);
+
+/**
+ * @brief **btf__relocate()** will check the split BTF *btf* for references
+ * to base BTF kinds, and verify those references are compatible with
+ * *base_btf*; if they are, *btf* is adjusted such that is re-parented to
+ * *base_btf* and type ids and strings are adjusted to accommodate this.
+ * @param btf split BTF object to relocate
+ * @param base_btf base BTF object
+ * @return 0 on success; negative error code, otherwise
+ *
+ * If successful, 0 is returned and **btf** now has **base_btf** as its
+ * base.
+ *
+ * A negative value is returned on error and the thread-local `errno` variable
+ * is set to the error code as well.
+ */
+LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf);
+
+struct btf_permute_opts {
+	size_t sz;
+	/* optional .BTF.ext info along the main BTF info */
+	struct btf_ext *btf_ext;
+	size_t :0;
+};
+#define btf_permute_opts__last_field btf_ext
+
+/**
+ * @brief **btf__permute()** rearranges BTF types in-place according to a specified ID mapping
+ * @param btf BTF object to permute
+ * @param id_map Array mapping original type IDs to new IDs
+ * @param id_map_cnt Number of elements in @id_map
+ * @param opts Optional parameters, including BTF extension data for reference updates
+ * @return 0 on success, negative error code on failure
+ *
+ * **btf__permute()** reorders BTF types based on the provided @id_map array,
+ * updating all internal type references to maintain consistency. The function
+ * operates in-place, modifying the BTF object directly.
+ *
+ * For **base BTF**:
+ * - @id_map must include all types from ID 0 to `btf__type_cnt(btf) - 1`
+ * - @id_map_cnt must be `btf__type_cnt(btf)`
+ * - Mapping is defined as `id_map[original_id] = new_id`
+ * - `id_map[0]` must be 0 (void type cannot be moved)
+ *
+ * For **split BTF**:
+ * - @id_map must include only split types (types added on top of the base BTF)
+ * - @id_map_cnt must be `btf__type_cnt(btf) - btf__type_cnt(btf__base_btf(btf))`
+ * - Mapping is defined as `id_map[original_id - start_id] = new_id`
+ * - `start_id` equals `btf__type_cnt(btf__base_btf(btf))`
+ *
+ * After permutation, all type references within the BTF data and optional
+ * BTF extension (if provided via @opts) are updated automatically.
+ *
+ * On error, returns a negative error code and sets errno:
+ *   - `-EINVAL`: Invalid parameters or invalid ID mapping
+ *   - `-ENOMEM`: Memory allocation failure
+ */
+LIBBPF_API int btf__permute(struct btf *btf, __u32 *id_map, __u32 id_map_cnt,
+			    const struct btf_permute_opts *opts);
+
+struct btf_dump;
+
+struct btf_dump_opts {
+	size_t sz;
+};
+#define btf_dump_opts__last_field sz
+
+typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
+
+LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
+					  btf_dump_printf_fn_t printf_fn,
+					  void *ctx,
+					  const struct btf_dump_opts *opts);
+
+LIBBPF_API void btf_dump__free(struct btf_dump *d);
+
+LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
+
+struct btf_dump_emit_type_decl_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* optional field name for type declaration, e.g.:
+	 * - struct my_struct <FNAME>
+	 * - void (*<FNAME>)(int)
+	 * - char (*<FNAME>)[123]
+	 */
+	const char *field_name;
+	/* extra indentation level (in number of tabs) to emit for multi-line
+	 * type declarations (e.g., anonymous struct); applies for lines
+	 * starting from the second one (first line is assumed to have
+	 * necessary indentation already
+	 */
+	int indent_level;
+	/* strip all the const/volatile/restrict mods */
+	bool strip_mods;
+	size_t :0;
+};
+#define btf_dump_emit_type_decl_opts__last_field strip_mods
+
+LIBBPF_API int
+btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
+			 const struct btf_dump_emit_type_decl_opts *opts);
+
+
+struct btf_dump_type_data_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	const char *indent_str;
+	int indent_level;
+	/* below match "show" flags for bpf_show_snprintf() */
+	bool compact;		/* no newlines/indentation */
+	bool skip_names;	/* skip member/type names */
+	bool emit_zeroes;	/* show 0-valued fields */
+	bool emit_strings;	/* print char arrays as strings */
+	size_t :0;
+};
+#define btf_dump_type_data_opts__last_field emit_strings
+
+LIBBPF_API int
+btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
+			 const void *data, size_t data_sz,
+			 const struct btf_dump_type_data_opts *opts);
+
+/*
+ * A set of helpers for easier BTF types handling.
+ *
+ * The inline functions below rely on constants from the kernel headers which
+ * may not be available for applications including this header file. To avoid
+ * compilation errors, we define all the constants here that were added after
+ * the initial introduction of the BTF_KIND* constants.
+ */
+#ifndef BTF_KIND_FUNC
+#define BTF_KIND_FUNC		12	/* Function	*/
+#define BTF_KIND_FUNC_PROTO	13	/* Function Proto	*/
+#endif
+#ifndef BTF_KIND_VAR
+#define BTF_KIND_VAR		14	/* Variable	*/
+#define BTF_KIND_DATASEC	15	/* Section	*/
+#endif
+#ifndef BTF_KIND_FLOAT
+#define BTF_KIND_FLOAT		16	/* Floating point	*/
+#endif
+/* The kernel header switched to enums, so the following were never #defined */
+#define BTF_KIND_DECL_TAG	17	/* Decl Tag */
+#define BTF_KIND_TYPE_TAG	18	/* Type Tag */
+#define BTF_KIND_ENUM64		19	/* Enum for up-to 64bit values */
+
+static inline __u16 btf_kind(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info);
+}
+
+static inline __u32 btf_vlen(const struct btf_type *t)
+{
+	return BTF_INFO_VLEN(t->info);
+}
+
+static inline bool btf_kflag(const struct btf_type *t)
+{
+	return BTF_INFO_KFLAG(t->info);
+}
+
+static inline bool btf_is_void(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_UNKN;
+}
+
+static inline bool btf_is_int(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_INT;
+}
+
+static inline bool btf_is_ptr(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_PTR;
+}
+
+static inline bool btf_is_array(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_ARRAY;
+}
+
+static inline bool btf_is_struct(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_STRUCT;
+}
+
+static inline bool btf_is_union(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_UNION;
+}
+
+static inline bool btf_is_composite(const struct btf_type *t)
+{
+	__u16 kind = btf_kind(t);
+
+	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
+}
+
+static inline bool btf_is_enum(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_ENUM;
+}
+
+static inline bool btf_is_enum64(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_ENUM64;
+}
+
+static inline bool btf_is_fwd(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_FWD;
+}
+
+static inline bool btf_is_typedef(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_TYPEDEF;
+}
+
+static inline bool btf_is_volatile(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_VOLATILE;
+}
+
+static inline bool btf_is_const(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_CONST;
+}
+
+static inline bool btf_is_restrict(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_RESTRICT;
+}
+
+static inline bool btf_is_mod(const struct btf_type *t)
+{
+	__u16 kind = btf_kind(t);
+
+	return kind == BTF_KIND_VOLATILE ||
+	       kind == BTF_KIND_CONST ||
+	       kind == BTF_KIND_RESTRICT ||
+	       kind == BTF_KIND_TYPE_TAG;
+}
+
+static inline bool btf_is_func(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_FUNC;
+}
+
+static inline bool btf_is_func_proto(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_FUNC_PROTO;
+}
+
+static inline bool btf_is_var(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_VAR;
+}
+
+static inline bool btf_is_datasec(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_DATASEC;
+}
+
+static inline bool btf_is_float(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_FLOAT;
+}
+
+static inline bool btf_is_decl_tag(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_DECL_TAG;
+}
+
+static inline bool btf_is_type_tag(const struct btf_type *t)
+{
+	return btf_kind(t) == BTF_KIND_TYPE_TAG;
+}
+
+static inline bool btf_is_any_enum(const struct btf_type *t)
+{
+	return btf_is_enum(t) || btf_is_enum64(t);
+}
+
+static inline bool btf_kind_core_compat(const struct btf_type *t1,
+					const struct btf_type *t2)
+{
+	return btf_kind(t1) == btf_kind(t2) ||
+	       (btf_is_any_enum(t1) && btf_is_any_enum(t2));
+}
+
+static inline __u8 btf_int_encoding(const struct btf_type *t)
+{
+	return BTF_INT_ENCODING(*(__u32 *)(t + 1));
+}
+
+static inline __u8 btf_int_offset(const struct btf_type *t)
+{
+	return BTF_INT_OFFSET(*(__u32 *)(t + 1));
+}
+
+static inline __u8 btf_int_bits(const struct btf_type *t)
+{
+	return BTF_INT_BITS(*(__u32 *)(t + 1));
+}
+
+static inline struct btf_array *btf_array(const struct btf_type *t)
+{
+	return (struct btf_array *)(t + 1);
+}
+
+static inline struct btf_enum *btf_enum(const struct btf_type *t)
+{
+	return (struct btf_enum *)(t + 1);
+}
+
+struct btf_enum64;
+
+static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
+{
+	return (struct btf_enum64 *)(t + 1);
+}
+
+static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
+{
+	/* struct btf_enum64 is introduced in Linux 6.0, which is very
+	 * bleeding-edge. Here we are avoiding relying on struct btf_enum64
+	 * definition coming from kernel UAPI headers to support wider range
+	 * of system-wide kernel headers.
+	 *
+	 * Given this header can be also included from C++ applications, that
+	 * further restricts C tricks we can use (like using compatible
+	 * anonymous struct). So just treat struct btf_enum64 as
+	 * a three-element array of u32 and access second (lo32) and third
+	 * (hi32) elements directly.
+	 *
+	 * For reference, here is a struct btf_enum64 definition:
+	 *
+	 * const struct btf_enum64 {
+	 *	__u32	name_off;
+	 *	__u32	val_lo32;
+	 *	__u32	val_hi32;
+	 * };
+	 */
+	const __u32 *e64 = (const __u32 *)e;
+
+	return ((__u64)e64[2] << 32) | e64[1];
+}
+
+static inline struct btf_member *btf_members(const struct btf_type *t)
+{
+	return (struct btf_member *)(t + 1);
+}
+
+/* Get bit offset of a member with specified index. */
+static inline __u32 btf_member_bit_offset(const struct btf_type *t,
+					  __u32 member_idx)
+{
+	const struct btf_member *m = btf_members(t) + member_idx;
+	bool kflag = btf_kflag(t);
+
+	return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
+}
+/*
+ * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
+ * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
+ */
+static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
+					     __u32 member_idx)
+{
+	const struct btf_member *m = btf_members(t) + member_idx;
+	bool kflag = btf_kflag(t);
+
+	return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
+}
+
+static inline struct btf_param *btf_params(const struct btf_type *t)
+{
+	return (struct btf_param *)(t + 1);
+}
+
+static inline struct btf_var *btf_var(const struct btf_type *t)
+{
+	return (struct btf_var *)(t + 1);
+}
+
+static inline struct btf_var_secinfo *
+btf_var_secinfos(const struct btf_type *t)
+{
+	return (struct btf_var_secinfo *)(t + 1);
+}
+
+struct btf_decl_tag;
+static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
+{
+	return (struct btf_decl_tag *)(t + 1);
+}
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* __LIBBPF_BTF_H */
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
new file mode 100644
index 000000000..123c448f2
--- /dev/null
+++ b/tools/lib/bpf/btf_dump.c
@@ -0,0 +1,2617 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * BTF-to-C type converter.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <endian.h>
+#include <errno.h>
+#include <limits.h>
+#include <linux/err.h>
+#include <linux/btf.h>
+#include <linux/kernel.h>
+#include "btf.h"
+#include "hashmap.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t";
+static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1;
+
+static const char *pfx(int lvl)
+{
+	return lvl >= PREFIX_CNT ? PREFIXES : &PREFIXES[PREFIX_CNT - lvl];
+}
+
+enum btf_dump_type_order_state {
+	NOT_ORDERED,
+	ORDERING,
+	ORDERED,
+};
+
+enum btf_dump_type_emit_state {
+	NOT_EMITTED,
+	EMITTING,
+	EMITTED,
+};
+
+/* per-type auxiliary state */
+struct btf_dump_type_aux_state {
+	/* topological sorting state */
+	enum btf_dump_type_order_state order_state: 2;
+	/* emitting state used to determine the need for forward declaration */
+	enum btf_dump_type_emit_state emit_state: 2;
+	/* whether forward declaration was already emitted */
+	__u8 fwd_emitted: 1;
+	/* whether unique non-duplicate name was already assigned */
+	__u8 name_resolved: 1;
+	/* whether type is referenced from any other type */
+	__u8 referenced: 1;
+};
+
+/* indent string length; one indent string is added for each indent level */
+#define BTF_DATA_INDENT_STR_LEN			32
+
+/*
+ * Common internal data for BTF type data dump operations.
+ */
+struct btf_dump_data {
+	const void *data_end;		/* end of valid data to show */
+	bool compact;
+	bool skip_names;
+	bool emit_zeroes;
+	bool emit_strings;
+	__u8 indent_lvl;	/* base indent level */
+	char indent_str[BTF_DATA_INDENT_STR_LEN];
+	/* below are used during iteration */
+	int depth;
+	bool is_array_member;
+	bool is_array_terminated;
+	bool is_array_char;
+};
+
+struct btf_dump {
+	const struct btf *btf;
+	btf_dump_printf_fn_t printf_fn;
+	void *cb_ctx;
+	int ptr_sz;
+	bool strip_mods;
+	bool skip_anon_defs;
+	int last_id;
+
+	/* per-type auxiliary state */
+	struct btf_dump_type_aux_state *type_states;
+	size_t type_states_cap;
+	/* per-type optional cached unique name, must be freed, if present */
+	const char **cached_names;
+	size_t cached_names_cap;
+
+	/* topo-sorted list of dependent type definitions */
+	__u32 *emit_queue;
+	int emit_queue_cap;
+	int emit_queue_cnt;
+
+	/*
+	 * stack of type declarations (e.g., chain of modifiers, arrays,
+	 * funcs, etc)
+	 */
+	__u32 *decl_stack;
+	int decl_stack_cap;
+	int decl_stack_cnt;
+
+	/* maps struct/union/enum name to a number of name occurrences */
+	struct hashmap *type_names;
+	/*
+	 * maps typedef identifiers and enum value names to a number of such
+	 * name occurrences
+	 */
+	struct hashmap *ident_names;
+	/*
+	 * data for typed display; allocated if needed.
+	 */
+	struct btf_dump_data *typed_dump;
+};
+
+static size_t str_hash_fn(long key, void *ctx)
+{
+	return str_hash((void *)key);
+}
+
+static bool str_equal_fn(long a, long b, void *ctx)
+{
+	return strcmp((void *)a, (void *)b) == 0;
+}
+
+static const char *btf_name_of(const struct btf_dump *d, __u32 name_off)
+{
+	return btf__name_by_offset(d->btf, name_off);
+}
+
+static void btf_dump_printf(const struct btf_dump *d, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	d->printf_fn(d->cb_ctx, fmt, args);
+	va_end(args);
+}
+
+static int btf_dump_mark_referenced(struct btf_dump *d);
+static int btf_dump_resize(struct btf_dump *d);
+
+struct btf_dump *btf_dump__new(const struct btf *btf,
+			       btf_dump_printf_fn_t printf_fn,
+			       void *ctx,
+			       const struct btf_dump_opts *opts)
+{
+	struct btf_dump *d;
+	int err;
+
+	if (!OPTS_VALID(opts, btf_dump_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	if (!printf_fn)
+		return libbpf_err_ptr(-EINVAL);
+
+	d = calloc(1, sizeof(struct btf_dump));
+	if (!d)
+		return libbpf_err_ptr(-ENOMEM);
+
+	d->btf = btf;
+	d->printf_fn = printf_fn;
+	d->cb_ctx = ctx;
+	d->ptr_sz = btf__pointer_size(btf) ? : sizeof(void *);
+
+	d->type_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
+	if (IS_ERR(d->type_names)) {
+		err = PTR_ERR(d->type_names);
+		d->type_names = NULL;
+		goto err;
+	}
+	d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
+	if (IS_ERR(d->ident_names)) {
+		err = PTR_ERR(d->ident_names);
+		d->ident_names = NULL;
+		goto err;
+	}
+
+	err = btf_dump_resize(d);
+	if (err)
+		goto err;
+
+	return d;
+err:
+	btf_dump__free(d);
+	return libbpf_err_ptr(err);
+}
+
+static int btf_dump_resize(struct btf_dump *d)
+{
+	int err, last_id = btf__type_cnt(d->btf) - 1;
+
+	if (last_id <= d->last_id)
+		return 0;
+
+	if (libbpf_ensure_mem((void **)&d->type_states, &d->type_states_cap,
+			      sizeof(*d->type_states), last_id + 1))
+		return -ENOMEM;
+	if (libbpf_ensure_mem((void **)&d->cached_names, &d->cached_names_cap,
+			      sizeof(*d->cached_names), last_id + 1))
+		return -ENOMEM;
+
+	if (d->last_id == 0) {
+		/* VOID is special */
+		d->type_states[0].order_state = ORDERED;
+		d->type_states[0].emit_state = EMITTED;
+	}
+
+	/* eagerly determine referenced types for anon enums */
+	err = btf_dump_mark_referenced(d);
+	if (err)
+		return err;
+
+	d->last_id = last_id;
+	return 0;
+}
+
+static void btf_dump_free_names(struct hashmap *map)
+{
+	size_t bkt;
+	struct hashmap_entry *cur;
+
+	if (!map)
+		return;
+
+	hashmap__for_each_entry(map, cur, bkt)
+		free((void *)cur->pkey);
+
+	hashmap__free(map);
+}
+
+void btf_dump__free(struct btf_dump *d)
+{
+	int i;
+
+	if (IS_ERR_OR_NULL(d))
+		return;
+
+	free(d->type_states);
+	if (d->cached_names) {
+		/* any set cached name is owned by us and should be freed */
+		for (i = 0; i <= d->last_id; i++) {
+			if (d->cached_names[i])
+				free((void *)d->cached_names[i]);
+		}
+	}
+	free(d->cached_names);
+	free(d->emit_queue);
+	free(d->decl_stack);
+	btf_dump_free_names(d->type_names);
+	btf_dump_free_names(d->ident_names);
+
+	free(d);
+}
+
+static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr);
+static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id);
+
+/*
+ * Dump BTF type in a compilable C syntax, including all the necessary
+ * dependent types, necessary for compilation. If some of the dependent types
+ * were already emitted as part of previous btf_dump__dump_type() invocation
+ * for another type, they won't be emitted again. This API allows callers to
+ * filter out BTF types according to user-defined criterias and emitted only
+ * minimal subset of types, necessary to compile everything. Full struct/union
+ * definitions will still be emitted, even if the only usage is through
+ * pointer and could be satisfied with just a forward declaration.
+ *
+ * Dumping is done in two high-level passes:
+ *   1. Topologically sort type definitions to satisfy C rules of compilation.
+ *   2. Emit type definitions in C syntax.
+ *
+ * Returns 0 on success; <0, otherwise.
+ */
+int btf_dump__dump_type(struct btf_dump *d, __u32 id)
+{
+	int err, i;
+
+	if (id >= btf__type_cnt(d->btf))
+		return libbpf_err(-EINVAL);
+
+	err = btf_dump_resize(d);
+	if (err)
+		return libbpf_err(err);
+
+	d->emit_queue_cnt = 0;
+	err = btf_dump_order_type(d, id, false);
+	if (err < 0)
+		return libbpf_err(err);
+
+	for (i = 0; i < d->emit_queue_cnt; i++)
+		btf_dump_emit_type(d, d->emit_queue[i], 0 /*top-level*/);
+
+	return 0;
+}
+
+/*
+ * Mark all types that are referenced from any other type. This is used to
+ * determine top-level anonymous enums that need to be emitted as an
+ * independent type declarations.
+ * Anonymous enums come in two flavors: either embedded in a struct's field
+ * definition, in which case they have to be declared inline as part of field
+ * type declaration; or as a top-level anonymous enum, typically used for
+ * declaring global constants. It's impossible to distinguish between two
+ * without knowing whether given enum type was referenced from other type:
+ * top-level anonymous enum won't be referenced by anything, while embedded
+ * one will.
+ */
+static int btf_dump_mark_referenced(struct btf_dump *d)
+{
+	int i, j, n = btf__type_cnt(d->btf);
+	const struct btf_type *t;
+	__u32 vlen;
+
+	for (i = d->last_id + 1; i < n; i++) {
+		t = btf__type_by_id(d->btf, i);
+		vlen = btf_vlen(t);
+
+		switch (btf_kind(t)) {
+		case BTF_KIND_INT:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+		case BTF_KIND_FWD:
+		case BTF_KIND_FLOAT:
+			break;
+
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_PTR:
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_FUNC:
+		case BTF_KIND_VAR:
+		case BTF_KIND_DECL_TAG:
+		case BTF_KIND_TYPE_TAG:
+			d->type_states[t->type].referenced = 1;
+			break;
+
+		case BTF_KIND_ARRAY: {
+			const struct btf_array *a = btf_array(t);
+
+			d->type_states[a->index_type].referenced = 1;
+			d->type_states[a->type].referenced = 1;
+			break;
+		}
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION: {
+			const struct btf_member *m = btf_members(t);
+
+			for (j = 0; j < vlen; j++, m++)
+				d->type_states[m->type].referenced = 1;
+			break;
+		}
+		case BTF_KIND_FUNC_PROTO: {
+			const struct btf_param *p = btf_params(t);
+
+			for (j = 0; j < vlen; j++, p++)
+				d->type_states[p->type].referenced = 1;
+			break;
+		}
+		case BTF_KIND_DATASEC: {
+			const struct btf_var_secinfo *v = btf_var_secinfos(t);
+
+			for (j = 0; j < vlen; j++, v++)
+				d->type_states[v->type].referenced = 1;
+			break;
+		}
+		default:
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static int btf_dump_add_emit_queue_id(struct btf_dump *d, __u32 id)
+{
+	__u32 *new_queue;
+	size_t new_cap;
+
+	if (d->emit_queue_cnt >= d->emit_queue_cap) {
+		new_cap = max(16, d->emit_queue_cap * 3 / 2);
+		new_queue = libbpf_reallocarray(d->emit_queue, new_cap, sizeof(new_queue[0]));
+		if (!new_queue)
+			return -ENOMEM;
+		d->emit_queue = new_queue;
+		d->emit_queue_cap = new_cap;
+	}
+
+	d->emit_queue[d->emit_queue_cnt++] = id;
+	return 0;
+}
+
+/*
+ * Determine order of emitting dependent types and specified type to satisfy
+ * C compilation rules.  This is done through topological sorting with an
+ * additional complication which comes from C rules. The main idea for C is
+ * that if some type is "embedded" into a struct/union, it's size needs to be
+ * known at the time of definition of containing type. E.g., for:
+ *
+ *	struct A {};
+ *	struct B { struct A x; }
+ *
+ * struct A *HAS* to be defined before struct B, because it's "embedded",
+ * i.e., it is part of struct B layout. But in the following case:
+ *
+ *	struct A;
+ *	struct B { struct A *x; }
+ *	struct A {};
+ *
+ * it's enough to just have a forward declaration of struct A at the time of
+ * struct B definition, as struct B has a pointer to struct A, so the size of
+ * field x is known without knowing struct A size: it's sizeof(void *).
+ *
+ * Unfortunately, there are some trickier cases we need to handle, e.g.:
+ *
+ *	struct A {}; // if this was forward-declaration: compilation error
+ *	struct B {
+ *		struct { // anonymous struct
+ *			struct A y;
+ *		} *x;
+ *	};
+ *
+ * In this case, struct B's field x is a pointer, so it's size is known
+ * regardless of the size of (anonymous) struct it points to. But because this
+ * struct is anonymous and thus defined inline inside struct B, *and* it
+ * embeds struct A, compiler requires full definition of struct A to be known
+ * before struct B can be defined. This creates a transitive dependency
+ * between struct A and struct B. If struct A was forward-declared before
+ * struct B definition and fully defined after struct B definition, that would
+ * trigger compilation error.
+ *
+ * All this means that while we are doing topological sorting on BTF type
+ * graph, we need to determine relationships between different types (graph
+ * nodes):
+ *   - weak link (relationship) between X and Y, if Y *CAN* be
+ *   forward-declared at the point of X definition;
+ *   - strong link, if Y *HAS* to be fully-defined before X can be defined.
+ *
+ * The rule is as follows. Given a chain of BTF types from X to Y, if there is
+ * BTF_KIND_PTR type in the chain and at least one non-anonymous type
+ * Z (excluding X, including Y), then link is weak. Otherwise, it's strong.
+ * Weak/strong relationship is determined recursively during DFS traversal and
+ * is returned as a result from btf_dump_order_type().
+ *
+ * btf_dump_order_type() is trying to avoid unnecessary forward declarations,
+ * but it is not guaranteeing that no extraneous forward declarations will be
+ * emitted.
+ *
+ * To avoid extra work, algorithm marks some of BTF types as ORDERED, when
+ * it's done with them, but not for all (e.g., VOLATILE, CONST, RESTRICT,
+ * ARRAY, FUNC_PROTO), as weak/strong semantics for those depends on the
+ * entire graph path, so depending where from one came to that BTF type, it
+ * might cause weak or strong ordering. For types like STRUCT/UNION/INT/ENUM,
+ * once they are processed, there is no need to do it again, so they are
+ * marked as ORDERED. We can mark PTR as ORDERED as well, as it semi-forces
+ * weak link, unless subsequent referenced STRUCT/UNION/ENUM is anonymous. But
+ * in any case, once those are processed, no need to do it again, as the
+ * result won't change.
+ *
+ * Returns:
+ *   - 1, if type is part of strong link (so there is strong topological
+ *   ordering requirements);
+ *   - 0, if type is part of weak link (so can be satisfied through forward
+ *   declaration);
+ *   - <0, on error (e.g., unsatisfiable type loop detected).
+ */
+static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
+{
+	/*
+	 * Order state is used to detect strong link cycles, but only for BTF
+	 * kinds that are or could be an independent definition (i.e.,
+	 * stand-alone fwd decl, enum, typedef, struct, union). Ptrs, arrays,
+	 * func_protos, modifiers are just means to get to these definitions.
+	 * Int/void don't need definitions, they are assumed to be always
+	 * properly defined.  We also ignore datasec, var, and funcs for now.
+	 * So for all non-defining kinds, we never even set ordering state,
+	 * for defining kinds we set ORDERING and subsequently ORDERED if it
+	 * forms a strong link.
+	 */
+	struct btf_dump_type_aux_state *tstate = &d->type_states[id];
+	const struct btf_type *t;
+	__u32 vlen;
+	int err, i;
+
+	/* return true, letting typedefs know that it's ok to be emitted */
+	if (tstate->order_state == ORDERED)
+		return 1;
+
+	t = btf__type_by_id(d->btf, id);
+
+	if (tstate->order_state == ORDERING) {
+		/* type loop, but resolvable through fwd declaration */
+		if (btf_is_composite(t) && through_ptr && t->name_off != 0)
+			return 0;
+		pr_warn("unsatisfiable type cycle, id:[%u]\n", id);
+		return -ELOOP;
+	}
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_INT:
+	case BTF_KIND_FLOAT:
+		tstate->order_state = ORDERED;
+		return 0;
+
+	case BTF_KIND_PTR:
+		err = btf_dump_order_type(d, t->type, true);
+		tstate->order_state = ORDERED;
+		return err;
+
+	case BTF_KIND_ARRAY:
+		return btf_dump_order_type(d, btf_array(t)->type, false);
+
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m = btf_members(t);
+		/*
+		 * struct/union is part of strong link, only if it's embedded
+		 * (so no ptr in a path) or it's anonymous (so has to be
+		 * defined inline, even if declared through ptr)
+		 */
+		if (through_ptr && t->name_off != 0)
+			return 0;
+
+		tstate->order_state = ORDERING;
+
+		vlen = btf_vlen(t);
+		for (i = 0; i < vlen; i++, m++) {
+			err = btf_dump_order_type(d, m->type, false);
+			if (err < 0)
+				return err;
+		}
+
+		if (t->name_off != 0) {
+			err = btf_dump_add_emit_queue_id(d, id);
+			if (err < 0)
+				return err;
+		}
+
+		tstate->order_state = ORDERED;
+		return 1;
+	}
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+	case BTF_KIND_FWD:
+		/*
+		 * non-anonymous or non-referenced enums are top-level
+		 * declarations and should be emitted. Same logic can be
+		 * applied to FWDs, it won't hurt anyways.
+		 */
+		if (t->name_off != 0 || !tstate->referenced) {
+			err = btf_dump_add_emit_queue_id(d, id);
+			if (err)
+				return err;
+		}
+		tstate->order_state = ORDERED;
+		return 1;
+
+	case BTF_KIND_TYPEDEF: {
+		int is_strong;
+
+		is_strong = btf_dump_order_type(d, t->type, through_ptr);
+		if (is_strong < 0)
+			return is_strong;
+
+		/* typedef is similar to struct/union w.r.t. fwd-decls */
+		if (through_ptr && !is_strong)
+			return 0;
+
+		/* typedef is always a named definition */
+		err = btf_dump_add_emit_queue_id(d, id);
+		if (err)
+			return err;
+
+		d->type_states[id].order_state = ORDERED;
+		return 1;
+	}
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_TYPE_TAG:
+		return btf_dump_order_type(d, t->type, through_ptr);
+
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *p = btf_params(t);
+		bool is_strong;
+
+		err = btf_dump_order_type(d, t->type, through_ptr);
+		if (err < 0)
+			return err;
+		is_strong = err > 0;
+
+		vlen = btf_vlen(t);
+		for (i = 0; i < vlen; i++, p++) {
+			err = btf_dump_order_type(d, p->type, through_ptr);
+			if (err < 0)
+				return err;
+			if (err > 0)
+				is_strong = true;
+		}
+		return is_strong;
+	}
+	case BTF_KIND_FUNC:
+	case BTF_KIND_VAR:
+	case BTF_KIND_DATASEC:
+	case BTF_KIND_DECL_TAG:
+		d->type_states[id].order_state = ORDERED;
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+					  const struct btf_type *t);
+
+static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
+				     const struct btf_type *t);
+static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id,
+				     const struct btf_type *t, int lvl);
+
+static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
+				   const struct btf_type *t);
+static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id,
+				   const struct btf_type *t, int lvl);
+
+static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id,
+				  const struct btf_type *t);
+
+static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id,
+				      const struct btf_type *t, int lvl);
+
+/* a local view into a shared stack */
+struct id_stack {
+	const __u32 *ids;
+	int cnt;
+};
+
+static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
+				    const char *fname, int lvl);
+static void btf_dump_emit_type_chain(struct btf_dump *d,
+				     struct id_stack *decl_stack,
+				     const char *fname, int lvl);
+
+static const char *btf_dump_type_name(struct btf_dump *d, __u32 id);
+static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id);
+static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
+				 const char *orig_name);
+
+static bool btf_dump_is_blacklisted(struct btf_dump *d, __u32 id)
+{
+	const struct btf_type *t = btf__type_by_id(d->btf, id);
+
+	/* __builtin_va_list is a compiler built-in, which causes compilation
+	 * errors, when compiling w/ different compiler, then used to compile
+	 * original code (e.g., GCC to compile kernel, Clang to use generated
+	 * C header from BTF). As it is built-in, it should be already defined
+	 * properly internally in compiler.
+	 */
+	if (t->name_off == 0)
+		return false;
+	return strcmp(btf_name_of(d, t->name_off), "__builtin_va_list") == 0;
+}
+
+/*
+ * Emit C-syntax definitions of types from chains of BTF types.
+ *
+ * High-level handling of determining necessary forward declarations are handled
+ * by btf_dump_emit_type() itself, but all nitty-gritty details of emitting type
+ * declarations/definitions in C syntax  are handled by a combo of
+ * btf_dump_emit_type_decl()/btf_dump_emit_type_chain() w/ delegation to
+ * corresponding btf_dump_emit_*_{def,fwd}() functions.
+ *
+ * We also keep track of "containing struct/union type ID" to determine when
+ * we reference it from inside and thus can avoid emitting unnecessary forward
+ * declaration.
+ *
+ * This algorithm is designed in such a way, that even if some error occurs
+ * (either technical, e.g., out of memory, or logical, i.e., malformed BTF
+ * that doesn't comply to C rules completely), algorithm will try to proceed
+ * and produce as much meaningful output as possible.
+ */
+static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
+{
+	struct btf_dump_type_aux_state *tstate = &d->type_states[id];
+	bool top_level_def = cont_id == 0;
+	const struct btf_type *t;
+	__u16 kind;
+
+	if (tstate->emit_state == EMITTED)
+		return;
+
+	t = btf__type_by_id(d->btf, id);
+	kind = btf_kind(t);
+
+	if (tstate->emit_state == EMITTING) {
+		if (tstate->fwd_emitted)
+			return;
+
+		switch (kind) {
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			/*
+			 * if we are referencing a struct/union that we are
+			 * part of - then no need for fwd declaration
+			 */
+			if (id == cont_id)
+				return;
+			if (t->name_off == 0) {
+				pr_warn("anonymous struct/union loop, id:[%u]\n",
+					id);
+				return;
+			}
+			btf_dump_emit_struct_fwd(d, id, t);
+			btf_dump_printf(d, ";\n\n");
+			tstate->fwd_emitted = 1;
+			break;
+		case BTF_KIND_TYPEDEF:
+			/*
+			 * for typedef fwd_emitted means typedef definition
+			 * was emitted, but it can be used only for "weak"
+			 * references through pointer only, not for embedding
+			 */
+			if (!btf_dump_is_blacklisted(d, id)) {
+				btf_dump_emit_typedef_def(d, id, t, 0);
+				btf_dump_printf(d, ";\n\n");
+			}
+			tstate->fwd_emitted = 1;
+			break;
+		default:
+			break;
+		}
+
+		return;
+	}
+
+	switch (kind) {
+	case BTF_KIND_INT:
+		/* Emit type alias definitions if necessary */
+		btf_dump_emit_missing_aliases(d, id, t);
+
+		tstate->emit_state = EMITTED;
+		break;
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		if (top_level_def) {
+			btf_dump_emit_enum_def(d, id, t, 0);
+			btf_dump_printf(d, ";\n\n");
+		}
+		tstate->emit_state = EMITTED;
+		break;
+	case BTF_KIND_PTR:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_TYPE_TAG:
+		btf_dump_emit_type(d, t->type, cont_id);
+		break;
+	case BTF_KIND_ARRAY:
+		btf_dump_emit_type(d, btf_array(t)->type, cont_id);
+		break;
+	case BTF_KIND_FWD:
+		btf_dump_emit_fwd_def(d, id, t);
+		btf_dump_printf(d, ";\n\n");
+		tstate->emit_state = EMITTED;
+		break;
+	case BTF_KIND_TYPEDEF:
+		tstate->emit_state = EMITTING;
+		btf_dump_emit_type(d, t->type, id);
+		/*
+		 * typedef can server as both definition and forward
+		 * declaration; at this stage someone depends on
+		 * typedef as a forward declaration (refers to it
+		 * through pointer), so unless we already did it,
+		 * emit typedef as a forward declaration
+		 */
+		if (!tstate->fwd_emitted && !btf_dump_is_blacklisted(d, id)) {
+			btf_dump_emit_typedef_def(d, id, t, 0);
+			btf_dump_printf(d, ";\n\n");
+		}
+		tstate->emit_state = EMITTED;
+		break;
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+		tstate->emit_state = EMITTING;
+		/* if it's a top-level struct/union definition or struct/union
+		 * is anonymous, then in C we'll be emitting all fields and
+		 * their types (as opposed to just `struct X`), so we need to
+		 * make sure that all types, referenced from struct/union
+		 * members have necessary forward-declarations, where
+		 * applicable
+		 */
+		if (top_level_def || t->name_off == 0) {
+			const struct btf_member *m = btf_members(t);
+			__u32 vlen = btf_vlen(t);
+			int i, new_cont_id;
+
+			new_cont_id = t->name_off == 0 ? cont_id : id;
+			for (i = 0; i < vlen; i++, m++)
+				btf_dump_emit_type(d, m->type, new_cont_id);
+		} else if (!tstate->fwd_emitted && id != cont_id) {
+			btf_dump_emit_struct_fwd(d, id, t);
+			btf_dump_printf(d, ";\n\n");
+			tstate->fwd_emitted = 1;
+		}
+
+		if (top_level_def) {
+			btf_dump_emit_struct_def(d, id, t, 0);
+			btf_dump_printf(d, ";\n\n");
+			tstate->emit_state = EMITTED;
+		} else {
+			tstate->emit_state = NOT_EMITTED;
+		}
+		break;
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *p = btf_params(t);
+		__u32 n = btf_vlen(t);
+		int i;
+
+		btf_dump_emit_type(d, t->type, cont_id);
+		for (i = 0; i < n; i++, p++)
+			btf_dump_emit_type(d, p->type, cont_id);
+
+		break;
+	}
+	default:
+		break;
+	}
+}
+
+static bool btf_is_struct_packed(const struct btf *btf, __u32 id,
+				 const struct btf_type *t)
+{
+	const struct btf_member *m;
+	int max_align = 1, align, i, bit_sz;
+	__u32 vlen;
+
+	m = btf_members(t);
+	vlen = btf_vlen(t);
+	/* all non-bitfield fields have to be naturally aligned */
+	for (i = 0; i < vlen; i++, m++) {
+		align = btf__align_of(btf, m->type);
+		bit_sz = btf_member_bitfield_size(t, i);
+		if (align && bit_sz == 0 && m->offset % (8 * align) != 0)
+			return true;
+		max_align = max(align, max_align);
+	}
+	/* size of a non-packed struct has to be a multiple of its alignment */
+	if (t->size % max_align != 0)
+		return true;
+	/*
+	 * if original struct was marked as packed, but its layout is
+	 * naturally aligned, we'll detect that it's not packed
+	 */
+	return false;
+}
+
+static void btf_dump_emit_bit_padding(const struct btf_dump *d,
+				      int cur_off, int next_off, int next_align,
+				      bool in_bitfield, int lvl)
+{
+	const struct {
+		const char *name;
+		int bits;
+	} pads[] = {
+		{"long", d->ptr_sz * 8}, {"int", 32}, {"short", 16}, {"char", 8}
+	};
+	int new_off = 0, pad_bits = 0, bits, i;
+	const char *pad_type = NULL;
+
+	if (cur_off >= next_off)
+		return; /* no gap */
+
+	/* For filling out padding we want to take advantage of
+	 * natural alignment rules to minimize unnecessary explicit
+	 * padding. First, we find the largest type (among long, int,
+	 * short, or char) that can be used to force naturally aligned
+	 * boundary. Once determined, we'll use such type to fill in
+	 * the remaining padding gap. In some cases we can rely on
+	 * compiler filling some gaps, but sometimes we need to force
+	 * alignment to close natural alignment with markers like
+	 * `long: 0` (this is always the case for bitfields).  Note
+	 * that even if struct itself has, let's say 4-byte alignment
+	 * (i.e., it only uses up to int-aligned types), using `long:
+	 * X;` explicit padding doesn't actually change struct's
+	 * overall alignment requirements, but compiler does take into
+	 * account that type's (long, in this example) natural
+	 * alignment requirements when adding implicit padding. We use
+	 * this fact heavily and don't worry about ruining correct
+	 * struct alignment requirement.
+	 */
+	for (i = 0; i < ARRAY_SIZE(pads); i++) {
+		pad_bits = pads[i].bits;
+		pad_type = pads[i].name;
+
+		new_off = roundup(cur_off, pad_bits);
+		if (new_off <= next_off)
+			break;
+	}
+
+	if (new_off > cur_off && new_off <= next_off) {
+		/* We need explicit `<type>: 0` aligning mark if next
+		 * field is right on alignment offset and its
+		 * alignment requirement is less strict than <type>'s
+		 * alignment (so compiler won't naturally align to the
+		 * offset we expect), or if subsequent `<type>: X`,
+		 * will actually completely fit in the remaining hole,
+		 * making compiler basically ignore `<type>: X`
+		 * completely.
+		 */
+		if (in_bitfield ||
+		    (new_off == next_off && roundup(cur_off, next_align * 8) != new_off) ||
+		    (new_off != next_off && next_off - new_off <= new_off - cur_off))
+			/* but for bitfields we'll emit explicit bit count */
+			btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type,
+					in_bitfield ? new_off - cur_off : 0);
+		cur_off = new_off;
+	}
+
+	/* Now we know we start at naturally aligned offset for a chosen
+	 * padding type (long, int, short, or char), and so the rest is just
+	 * a straightforward filling of remaining padding gap with full
+	 * `<type>: sizeof(<type>);` markers, except for the last one, which
+	 * might need smaller than sizeof(<type>) padding.
+	 */
+	while (cur_off != next_off) {
+		bits = min(next_off - cur_off, pad_bits);
+		if (bits == pad_bits) {
+			btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, pad_bits);
+			cur_off += bits;
+			continue;
+		}
+		/* For the remainder padding that doesn't cover entire
+		 * pad_type bit length, we pick the smallest necessary type.
+		 * This is pure aesthetics, we could have just used `long`,
+		 * but having smallest necessary one communicates better the
+		 * scale of the padding gap.
+		 */
+		for (i = ARRAY_SIZE(pads) - 1; i >= 0; i--) {
+			pad_type = pads[i].name;
+			pad_bits = pads[i].bits;
+			if (pad_bits < bits)
+				continue;
+
+			btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, bits);
+			cur_off += bits;
+			break;
+		}
+	}
+}
+
+static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
+				     const struct btf_type *t)
+{
+	btf_dump_printf(d, "%s%s%s",
+			btf_is_struct(t) ? "struct" : "union",
+			t->name_off ? " " : "",
+			btf_dump_type_name(d, id));
+}
+
+static void btf_dump_emit_struct_def(struct btf_dump *d,
+				     __u32 id,
+				     const struct btf_type *t,
+				     int lvl)
+{
+	const struct btf_member *m = btf_members(t);
+	bool is_struct = btf_is_struct(t);
+	bool packed, prev_bitfield = false;
+	int align, i, off = 0;
+	__u32 vlen = btf_vlen(t);
+
+	align = btf__align_of(d->btf, id);
+	packed = is_struct ? btf_is_struct_packed(d->btf, id, t) : 0;
+
+	btf_dump_printf(d, "%s%s%s {",
+			is_struct ? "struct" : "union",
+			t->name_off ? " " : "",
+			btf_dump_type_name(d, id));
+
+	for (i = 0; i < vlen; i++, m++) {
+		const char *fname;
+		int m_off, m_sz, m_align;
+		bool in_bitfield;
+
+		fname = btf_name_of(d, m->name_off);
+		m_sz = btf_member_bitfield_size(t, i);
+		m_off = btf_member_bit_offset(t, i);
+		m_align = packed ? 1 : btf__align_of(d->btf, m->type);
+
+		in_bitfield = prev_bitfield && m_sz != 0;
+
+		btf_dump_emit_bit_padding(d, off, m_off, m_align, in_bitfield, lvl + 1);
+		btf_dump_printf(d, "\n%s", pfx(lvl + 1));
+		btf_dump_emit_type_decl(d, m->type, fname, lvl + 1);
+
+		if (m_sz) {
+			btf_dump_printf(d, ": %d", m_sz);
+			off = m_off + m_sz;
+			prev_bitfield = true;
+		} else {
+			m_sz = max((__s64)0, btf__resolve_size(d->btf, m->type));
+			off = m_off + m_sz * 8;
+			prev_bitfield = false;
+		}
+
+		btf_dump_printf(d, ";");
+	}
+
+	/* pad at the end, if necessary */
+	if (is_struct)
+		btf_dump_emit_bit_padding(d, off, t->size * 8, align, false, lvl + 1);
+
+	/*
+	 * Keep `struct empty {}` on a single line,
+	 * only print newline when there are regular or padding fields.
+	 */
+	if (vlen || t->size) {
+		btf_dump_printf(d, "\n");
+		btf_dump_printf(d, "%s}", pfx(lvl));
+	} else {
+		btf_dump_printf(d, "}");
+	}
+	if (packed)
+		btf_dump_printf(d, " __attribute__((packed))");
+}
+
+static const char *missing_base_types[][2] = {
+	/*
+	 * GCC emits typedefs to its internal __PolyX_t types when compiling Arm
+	 * SIMD intrinsics. Alias them to standard base types.
+	 */
+	{ "__Poly8_t",		"unsigned char" },
+	{ "__Poly16_t",		"unsigned short" },
+	{ "__Poly64_t",		"unsigned long long" },
+	{ "__Poly128_t",	"unsigned __int128" },
+};
+
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+					  const struct btf_type *t)
+{
+	const char *name = btf_dump_type_name(d, id);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) {
+		if (strcmp(name, missing_base_types[i][0]) == 0) {
+			btf_dump_printf(d, "typedef %s %s;\n\n",
+					missing_base_types[i][1], name);
+			break;
+		}
+	}
+}
+
+static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
+				   const struct btf_type *t)
+{
+	btf_dump_printf(d, "enum %s", btf_dump_type_name(d, id));
+}
+
+static void btf_dump_emit_enum32_val(struct btf_dump *d,
+				     const struct btf_type *t,
+				     int lvl, __u32 vlen)
+{
+	const struct btf_enum *v = btf_enum(t);
+	bool is_signed = btf_kflag(t);
+	const char *fmt_str;
+	const char *name;
+	size_t dup_cnt;
+	int i;
+
+	for (i = 0; i < vlen; i++, v++) {
+		name = btf_name_of(d, v->name_off);
+		/* enumerators share namespace with typedef idents */
+		dup_cnt = btf_dump_name_dups(d, d->ident_names, name);
+		if (dup_cnt > 1) {
+			fmt_str = is_signed ? "\n%s%s___%zd = %d," : "\n%s%s___%zd = %u,";
+			btf_dump_printf(d, fmt_str, pfx(lvl + 1), name, dup_cnt, v->val);
+		} else {
+			fmt_str = is_signed ? "\n%s%s = %d," : "\n%s%s = %u,";
+			btf_dump_printf(d, fmt_str, pfx(lvl + 1), name, v->val);
+		}
+	}
+}
+
+static void btf_dump_emit_enum64_val(struct btf_dump *d,
+				     const struct btf_type *t,
+				     int lvl, __u32 vlen)
+{
+	const struct btf_enum64 *v = btf_enum64(t);
+	bool is_signed = btf_kflag(t);
+	const char *fmt_str;
+	const char *name;
+	size_t dup_cnt;
+	__u64 val;
+	int i;
+
+	for (i = 0; i < vlen; i++, v++) {
+		name = btf_name_of(d, v->name_off);
+		dup_cnt = btf_dump_name_dups(d, d->ident_names, name);
+		val = btf_enum64_value(v);
+		if (dup_cnt > 1) {
+			fmt_str = is_signed ? "\n%s%s___%zd = %lldLL,"
+					    : "\n%s%s___%zd = %lluULL,";
+			btf_dump_printf(d, fmt_str,
+					pfx(lvl + 1), name, dup_cnt,
+					(unsigned long long)val);
+		} else {
+			fmt_str = is_signed ? "\n%s%s = %lldLL,"
+					    : "\n%s%s = %lluULL,";
+			btf_dump_printf(d, fmt_str,
+					pfx(lvl + 1), name,
+					(unsigned long long)val);
+		}
+	}
+}
+static void btf_dump_emit_enum_def(struct btf_dump *d, __u32 id,
+				   const struct btf_type *t,
+				   int lvl)
+{
+	__u32 vlen = btf_vlen(t);
+
+	btf_dump_printf(d, "enum%s%s",
+			t->name_off ? " " : "",
+			btf_dump_type_name(d, id));
+
+	if (!vlen)
+		return;
+
+	btf_dump_printf(d, " {");
+	if (btf_is_enum(t))
+		btf_dump_emit_enum32_val(d, t, lvl, vlen);
+	else
+		btf_dump_emit_enum64_val(d, t, lvl, vlen);
+	btf_dump_printf(d, "\n%s}", pfx(lvl));
+
+	/* special case enums with special sizes */
+	if (t->size == 1) {
+		/* one-byte enums can be forced with mode(byte) attribute */
+		btf_dump_printf(d, " __attribute__((mode(byte)))");
+	} else if (t->size == 8 && d->ptr_sz == 8) {
+		/* enum can be 8-byte sized if one of the enumerator values
+		 * doesn't fit in 32-bit integer, or by adding mode(word)
+		 * attribute (but probably only on 64-bit architectures); do
+		 * our best here to try to satisfy the contract without adding
+		 * unnecessary attributes
+		 */
+		bool needs_word_mode;
+
+		if (btf_is_enum(t)) {
+			/* enum can't represent 64-bit values, so we need word mode */
+			needs_word_mode = true;
+		} else {
+			/* enum64 needs mode(word) if none of its values has
+			 * non-zero upper 32-bits (which means that all values
+			 * fit in 32-bit integers and won't cause compiler to
+			 * bump enum to be 64-bit naturally
+			 */
+			int i;
+
+			needs_word_mode = true;
+			for (i = 0; i < vlen; i++) {
+				if (btf_enum64(t)[i].val_hi32 != 0) {
+					needs_word_mode = false;
+					break;
+				}
+			}
+		}
+		if (needs_word_mode)
+			btf_dump_printf(d, " __attribute__((mode(word)))");
+	}
+
+}
+
+static void btf_dump_emit_fwd_def(struct btf_dump *d, __u32 id,
+				  const struct btf_type *t)
+{
+	const char *name = btf_dump_type_name(d, id);
+
+	if (btf_kflag(t))
+		btf_dump_printf(d, "union %s", name);
+	else
+		btf_dump_printf(d, "struct %s", name);
+}
+
+static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id,
+				     const struct btf_type *t, int lvl)
+{
+	const char *name = btf_dump_ident_name(d, id);
+
+	/*
+	 * Old GCC versions are emitting invalid typedef for __gnuc_va_list
+	 * pointing to VOID. This generates warnings from btf_dump() and
+	 * results in uncompilable header file, so we are fixing it up here
+	 * with valid typedef into __builtin_va_list.
+	 */
+	if (t->type == 0 && strcmp(name, "__gnuc_va_list") == 0) {
+		btf_dump_printf(d, "typedef __builtin_va_list __gnuc_va_list");
+		return;
+	}
+
+	btf_dump_printf(d, "typedef ");
+	btf_dump_emit_type_decl(d, t->type, name, lvl);
+}
+
+static int btf_dump_push_decl_stack_id(struct btf_dump *d, __u32 id)
+{
+	__u32 *new_stack;
+	size_t new_cap;
+
+	if (d->decl_stack_cnt >= d->decl_stack_cap) {
+		new_cap = max(16, d->decl_stack_cap * 3 / 2);
+		new_stack = libbpf_reallocarray(d->decl_stack, new_cap, sizeof(new_stack[0]));
+		if (!new_stack)
+			return -ENOMEM;
+		d->decl_stack = new_stack;
+		d->decl_stack_cap = new_cap;
+	}
+
+	d->decl_stack[d->decl_stack_cnt++] = id;
+
+	return 0;
+}
+
+/*
+ * Emit type declaration (e.g., field type declaration in a struct or argument
+ * declaration in function prototype) in correct C syntax.
+ *
+ * For most types it's trivial, but there are few quirky type declaration
+ * cases worth mentioning:
+ *   - function prototypes (especially nesting of function prototypes);
+ *   - arrays;
+ *   - const/volatile/restrict for pointers vs other types.
+ *
+ * For a good discussion of *PARSING* C syntax (as a human), see
+ * Peter van der Linden's "Expert C Programming: Deep C Secrets",
+ * Ch.3 "Unscrambling Declarations in C".
+ *
+ * It won't help with BTF to C conversion much, though, as it's an opposite
+ * problem. So we came up with this algorithm in reverse to van der Linden's
+ * parsing algorithm. It goes from structured BTF representation of type
+ * declaration to a valid compilable C syntax.
+ *
+ * For instance, consider this C typedef:
+ *	typedef const int * const * arr[10] arr_t;
+ * It will be represented in BTF with this chain of BTF types:
+ *	[typedef] -> [array] -> [ptr] -> [const] -> [ptr] -> [const] -> [int]
+ *
+ * Notice how [const] modifier always goes before type it modifies in BTF type
+ * graph, but in C syntax, const/volatile/restrict modifiers are written to
+ * the right of pointers, but to the left of other types. There are also other
+ * quirks, like function pointers, arrays of them, functions returning other
+ * functions, etc.
+ *
+ * We handle that by pushing all the types to a stack, until we hit "terminal"
+ * type (int/enum/struct/union/fwd). Then depending on the kind of a type on
+ * top of a stack, modifiers are handled differently. Array/function pointers
+ * have also wildly different syntax and how nesting of them are done. See
+ * code for authoritative definition.
+ *
+ * To avoid allocating new stack for each independent chain of BTF types, we
+ * share one bigger stack, with each chain working only on its own local view
+ * of a stack frame. Some care is required to "pop" stack frames after
+ * processing type declaration chain.
+ */
+int btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
+			     const struct btf_dump_emit_type_decl_opts *opts)
+{
+	const char *fname;
+	int lvl, err;
+
+	if (!OPTS_VALID(opts, btf_dump_emit_type_decl_opts))
+		return libbpf_err(-EINVAL);
+
+	err = btf_dump_resize(d);
+	if (err)
+		return libbpf_err(err);
+
+	fname = OPTS_GET(opts, field_name, "");
+	lvl = OPTS_GET(opts, indent_level, 0);
+	d->strip_mods = OPTS_GET(opts, strip_mods, false);
+	btf_dump_emit_type_decl(d, id, fname, lvl);
+	d->strip_mods = false;
+	return 0;
+}
+
+static void btf_dump_emit_type_decl(struct btf_dump *d, __u32 id,
+				    const char *fname, int lvl)
+{
+	struct id_stack decl_stack;
+	const struct btf_type *t;
+	int err, stack_start;
+
+	stack_start = d->decl_stack_cnt;
+	for (;;) {
+		t = btf__type_by_id(d->btf, id);
+		if (d->strip_mods && btf_is_mod(t))
+			goto skip_mod;
+
+		err = btf_dump_push_decl_stack_id(d, id);
+		if (err < 0) {
+			/*
+			 * if we don't have enough memory for entire type decl
+			 * chain, restore stack, emit warning, and try to
+			 * proceed nevertheless
+			 */
+			pr_warn("not enough memory for decl stack: %s\n", errstr(err));
+			d->decl_stack_cnt = stack_start;
+			return;
+		}
+skip_mod:
+		/* VOID */
+		if (id == 0)
+			break;
+
+		switch (btf_kind(t)) {
+		case BTF_KIND_PTR:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_FUNC_PROTO:
+		case BTF_KIND_TYPE_TAG:
+			id = t->type;
+			break;
+		case BTF_KIND_ARRAY:
+			id = btf_array(t)->type;
+			break;
+		case BTF_KIND_INT:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+		case BTF_KIND_FWD:
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_FLOAT:
+			goto done;
+		default:
+			pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n",
+				btf_kind(t), id);
+			goto done;
+		}
+	}
+done:
+	/*
+	 * We might be inside a chain of declarations (e.g., array of function
+	 * pointers returning anonymous (so inlined) structs, having another
+	 * array field). Each of those needs its own "stack frame" to handle
+	 * emitting of declarations. Those stack frames are non-overlapping
+	 * portions of shared btf_dump->decl_stack. To make it a bit nicer to
+	 * handle this set of nested stacks, we create a view corresponding to
+	 * our own "stack frame" and work with it as an independent stack.
+	 * We'll need to clean up after emit_type_chain() returns, though.
+	 */
+	decl_stack.ids = d->decl_stack + stack_start;
+	decl_stack.cnt = d->decl_stack_cnt - stack_start;
+	btf_dump_emit_type_chain(d, &decl_stack, fname, lvl);
+	/*
+	 * emit_type_chain() guarantees that it will pop its entire decl_stack
+	 * frame before returning. But it works with a read-only view into
+	 * decl_stack, so it doesn't actually pop anything from the
+	 * perspective of shared btf_dump->decl_stack, per se. We need to
+	 * reset decl_stack state to how it was before us to avoid it growing
+	 * all the time.
+	 */
+	d->decl_stack_cnt = stack_start;
+}
+
+static void btf_dump_emit_mods(struct btf_dump *d, struct id_stack *decl_stack)
+{
+	const struct btf_type *t;
+	__u32 id;
+
+	while (decl_stack->cnt) {
+		id = decl_stack->ids[decl_stack->cnt - 1];
+		t = btf__type_by_id(d->btf, id);
+
+		switch (btf_kind(t)) {
+		case BTF_KIND_VOLATILE:
+			btf_dump_printf(d, "volatile ");
+			break;
+		case BTF_KIND_CONST:
+			btf_dump_printf(d, "const ");
+			break;
+		case BTF_KIND_RESTRICT:
+			btf_dump_printf(d, "restrict ");
+			break;
+		default:
+			return;
+		}
+		decl_stack->cnt--;
+	}
+}
+
+static void btf_dump_drop_mods(struct btf_dump *d, struct id_stack *decl_stack)
+{
+	const struct btf_type *t;
+	__u32 id;
+
+	while (decl_stack->cnt) {
+		id = decl_stack->ids[decl_stack->cnt - 1];
+		t = btf__type_by_id(d->btf, id);
+		if (!btf_is_mod(t))
+			return;
+		decl_stack->cnt--;
+	}
+}
+
+static void btf_dump_emit_name(const struct btf_dump *d,
+			       const char *name, bool last_was_ptr)
+{
+	bool separate = name[0] && !last_was_ptr;
+
+	btf_dump_printf(d, "%s%s", separate ? " " : "", name);
+}
+
+static void btf_dump_emit_type_chain(struct btf_dump *d,
+				     struct id_stack *decls,
+				     const char *fname, int lvl)
+{
+	/*
+	 * last_was_ptr is used to determine if we need to separate pointer
+	 * asterisk (*) from previous part of type signature with space, so
+	 * that we get `int ***`, instead of `int * * *`. We default to true
+	 * for cases where we have single pointer in a chain. E.g., in ptr ->
+	 * func_proto case. func_proto will start a new emit_type_chain call
+	 * with just ptr, which should be emitted as (*) or (*<fname>), so we
+	 * don't want to prepend space for that last pointer.
+	 */
+	bool last_was_ptr = true;
+	const struct btf_type *t;
+	const char *name;
+	__u16 kind;
+	__u32 id;
+
+	while (decls->cnt) {
+		id = decls->ids[--decls->cnt];
+		if (id == 0) {
+			/* VOID is a special snowflake */
+			btf_dump_emit_mods(d, decls);
+			btf_dump_printf(d, "void");
+			last_was_ptr = false;
+			continue;
+		}
+
+		t = btf__type_by_id(d->btf, id);
+		kind = btf_kind(t);
+
+		switch (kind) {
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+			btf_dump_emit_mods(d, decls);
+			name = btf_name_of(d, t->name_off);
+			btf_dump_printf(d, "%s", name);
+			break;
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			btf_dump_emit_mods(d, decls);
+			/* inline anonymous struct/union */
+			if (t->name_off == 0 && !d->skip_anon_defs)
+				btf_dump_emit_struct_def(d, id, t, lvl);
+			else
+				btf_dump_emit_struct_fwd(d, id, t);
+			break;
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+			btf_dump_emit_mods(d, decls);
+			/* inline anonymous enum */
+			if (t->name_off == 0 && !d->skip_anon_defs)
+				btf_dump_emit_enum_def(d, id, t, lvl);
+			else
+				btf_dump_emit_enum_fwd(d, id, t);
+			break;
+		case BTF_KIND_FWD:
+			btf_dump_emit_mods(d, decls);
+			btf_dump_emit_fwd_def(d, id, t);
+			break;
+		case BTF_KIND_TYPEDEF:
+			btf_dump_emit_mods(d, decls);
+			btf_dump_printf(d, "%s", btf_dump_ident_name(d, id));
+			break;
+		case BTF_KIND_PTR:
+			btf_dump_printf(d, "%s", last_was_ptr ? "*" : " *");
+			break;
+		case BTF_KIND_VOLATILE:
+			btf_dump_printf(d, " volatile");
+			break;
+		case BTF_KIND_CONST:
+			btf_dump_printf(d, " const");
+			break;
+		case BTF_KIND_RESTRICT:
+			btf_dump_printf(d, " restrict");
+			break;
+		case BTF_KIND_TYPE_TAG:
+			btf_dump_emit_mods(d, decls);
+			name = btf_name_of(d, t->name_off);
+			if (btf_kflag(t))
+				btf_dump_printf(d, " __attribute__((%s))", name);
+			else
+				btf_dump_printf(d, " __attribute__((btf_type_tag(\"%s\")))", name);
+			break;
+		case BTF_KIND_ARRAY: {
+			const struct btf_array *a = btf_array(t);
+			const struct btf_type *next_t;
+			__u32 next_id;
+			bool multidim;
+			/*
+			 * GCC has a bug
+			 * (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=8354)
+			 * which causes it to emit extra const/volatile
+			 * modifiers for an array, if array's element type has
+			 * const/volatile modifiers. Clang doesn't do that.
+			 * In general, it doesn't seem very meaningful to have
+			 * a const/volatile modifier for array, so we are
+			 * going to silently skip them here.
+			 */
+			btf_dump_drop_mods(d, decls);
+
+			if (decls->cnt == 0) {
+				btf_dump_emit_name(d, fname, last_was_ptr);
+				btf_dump_printf(d, "[%u]", a->nelems);
+				return;
+			}
+
+			next_id = decls->ids[decls->cnt - 1];
+			next_t = btf__type_by_id(d->btf, next_id);
+			multidim = btf_is_array(next_t);
+			/* we need space if we have named non-pointer */
+			if (fname[0] && !last_was_ptr)
+				btf_dump_printf(d, " ");
+			/* no parentheses for multi-dimensional array */
+			if (!multidim)
+				btf_dump_printf(d, "(");
+			btf_dump_emit_type_chain(d, decls, fname, lvl);
+			if (!multidim)
+				btf_dump_printf(d, ")");
+			btf_dump_printf(d, "[%u]", a->nelems);
+			return;
+		}
+		case BTF_KIND_FUNC_PROTO: {
+			const struct btf_param *p = btf_params(t);
+			__u32 vlen = btf_vlen(t);
+			int i;
+
+			/*
+			 * GCC emits extra volatile qualifier for
+			 * __attribute__((noreturn)) function pointers. Clang
+			 * doesn't do it. It's a GCC quirk for backwards
+			 * compatibility with code written for GCC <2.5. So,
+			 * similarly to extra qualifiers for array, just drop
+			 * them, instead of handling them.
+			 */
+			btf_dump_drop_mods(d, decls);
+			if (decls->cnt) {
+				btf_dump_printf(d, " (");
+				btf_dump_emit_type_chain(d, decls, fname, lvl);
+				btf_dump_printf(d, ")");
+			} else {
+				btf_dump_emit_name(d, fname, last_was_ptr);
+			}
+			btf_dump_printf(d, "(");
+			/*
+			 * Clang for BPF target generates func_proto with no
+			 * args as a func_proto with a single void arg (e.g.,
+			 * `int (*f)(void)` vs just `int (*f)()`). We are
+			 * going to emit valid empty args (void) syntax for
+			 * such case. Similarly and conveniently, valid
+			 * no args case can be special-cased here as well.
+			 */
+			if (vlen == 0 || (vlen == 1 && p->type == 0)) {
+				btf_dump_printf(d, "void)");
+				return;
+			}
+
+			for (i = 0; i < vlen; i++, p++) {
+				if (i > 0)
+					btf_dump_printf(d, ", ");
+
+				/* last arg of type void is vararg */
+				if (i == vlen - 1 && p->type == 0) {
+					btf_dump_printf(d, "...");
+					break;
+				}
+
+				name = btf_name_of(d, p->name_off);
+				btf_dump_emit_type_decl(d, p->type, name, lvl);
+			}
+
+			btf_dump_printf(d, ")");
+			return;
+		}
+		default:
+			pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n",
+				kind, id);
+			return;
+		}
+
+		last_was_ptr = kind == BTF_KIND_PTR;
+	}
+
+	btf_dump_emit_name(d, fname, last_was_ptr);
+}
+
+/* show type name as (type_name) */
+static void btf_dump_emit_type_cast(struct btf_dump *d, __u32 id,
+				    bool top_level)
+{
+	const struct btf_type *t;
+
+	/* for array members, we don't bother emitting type name for each
+	 * member to avoid the redundancy of
+	 * .name = (char[4])[(char)'f',(char)'o',(char)'o',]
+	 */
+	if (d->typed_dump->is_array_member)
+		return;
+
+	/* avoid type name specification for variable/section; it will be done
+	 * for the associated variable value(s).
+	 */
+	t = btf__type_by_id(d->btf, id);
+	if (btf_is_var(t) || btf_is_datasec(t))
+		return;
+
+	if (top_level)
+		btf_dump_printf(d, "(");
+
+	d->skip_anon_defs = true;
+	d->strip_mods = true;
+	btf_dump_emit_type_decl(d, id, "", 0);
+	d->strip_mods = false;
+	d->skip_anon_defs = false;
+
+	if (top_level)
+		btf_dump_printf(d, ")");
+}
+
+/* return number of duplicates (occurrences) of a given name */
+static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
+				 const char *orig_name)
+{
+	char *old_name, *new_name;
+	size_t dup_cnt = 0;
+	int err;
+
+	new_name = strdup(orig_name);
+	if (!new_name)
+		return 1;
+
+	(void)hashmap__find(name_map, orig_name, &dup_cnt);
+	dup_cnt++;
+
+	err = hashmap__set(name_map, new_name, dup_cnt, &old_name, NULL);
+	if (err)
+		free(new_name);
+
+	free(old_name);
+
+	return dup_cnt;
+}
+
+static const char *btf_dump_resolve_name(struct btf_dump *d, __u32 id,
+					 struct hashmap *name_map)
+{
+	struct btf_dump_type_aux_state *s = &d->type_states[id];
+	const struct btf_type *t = btf__type_by_id(d->btf, id);
+	const char *orig_name = btf_name_of(d, t->name_off);
+	const char **cached_name = &d->cached_names[id];
+	size_t dup_cnt;
+
+	if (t->name_off == 0)
+		return "";
+
+	if (s->name_resolved)
+		return *cached_name ? *cached_name : orig_name;
+
+	if (btf_is_fwd(t) || (btf_is_enum(t) && btf_vlen(t) == 0)) {
+		s->name_resolved = 1;
+		return orig_name;
+	}
+
+	dup_cnt = btf_dump_name_dups(d, name_map, orig_name);
+	if (dup_cnt > 1) {
+		const size_t max_len = 256;
+		char new_name[max_len];
+
+		snprintf(new_name, max_len, "%s___%zu", orig_name, dup_cnt);
+		*cached_name = strdup(new_name);
+	}
+
+	s->name_resolved = 1;
+	return *cached_name ? *cached_name : orig_name;
+}
+
+static const char *btf_dump_type_name(struct btf_dump *d, __u32 id)
+{
+	return btf_dump_resolve_name(d, id, d->type_names);
+}
+
+static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id)
+{
+	return btf_dump_resolve_name(d, id, d->ident_names);
+}
+
+static int btf_dump_dump_type_data(struct btf_dump *d,
+				   const char *fname,
+				   const struct btf_type *t,
+				   __u32 id,
+				   const void *data,
+				   __u8 bits_offset,
+				   __u8 bit_sz);
+
+static const char *btf_dump_data_newline(struct btf_dump *d)
+{
+	return d->typed_dump->compact || d->typed_dump->depth == 0 ? "" : "\n";
+}
+
+static const char *btf_dump_data_delim(struct btf_dump *d)
+{
+	return d->typed_dump->depth == 0 ? "" : ",";
+}
+
+static void btf_dump_data_pfx(struct btf_dump *d)
+{
+	int i, lvl = d->typed_dump->indent_lvl + d->typed_dump->depth;
+
+	if (d->typed_dump->compact)
+		return;
+
+	for (i = 0; i < lvl; i++)
+		btf_dump_printf(d, "%s", d->typed_dump->indent_str);
+}
+
+/* A macro is used here as btf_type_value[s]() appends format specifiers
+ * to the format specifier passed in; these do the work of appending
+ * delimiters etc while the caller simply has to specify the type values
+ * in the format specifier + value(s).
+ */
+#define btf_dump_type_values(d, fmt, ...)				\
+	btf_dump_printf(d, fmt "%s%s",					\
+			##__VA_ARGS__,					\
+			btf_dump_data_delim(d),				\
+			btf_dump_data_newline(d))
+
+static int btf_dump_unsupported_data(struct btf_dump *d,
+				     const struct btf_type *t,
+				     __u32 id)
+{
+	btf_dump_printf(d, "<unsupported kind:%u>", btf_kind(t));
+	return -ENOTSUP;
+}
+
+static int btf_dump_get_bitfield_value(struct btf_dump *d,
+				       const struct btf_type *t,
+				       const void *data,
+				       __u8 bits_offset,
+				       __u8 bit_sz,
+				       __u64 *value)
+{
+	__u16 left_shift_bits, right_shift_bits;
+	const __u8 *bytes = data;
+	__u8 nr_copy_bits;
+	__u8 start_bit, nr_bytes;
+	__u64 num = 0;
+	int i;
+
+	/* Calculate how many bytes cover the bitfield */
+	start_bit = bits_offset % 8;
+	nr_bytes = (start_bit + bit_sz + 7) / 8;
+
+	/* Bound check */
+	if (data + nr_bytes > d->typed_dump->data_end)
+		return -E2BIG;
+
+	/* Maximum supported bitfield size is 64 bits */
+	if (t->size > 8) {
+		pr_warn("unexpected bitfield size %u\n", t->size);
+		return -EINVAL;
+	}
+
+	/* Bitfield value retrieval is done in two steps; first relevant bytes are
+	 * stored in num, then we left/right shift num to eliminate irrelevant bits.
+	 */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	for (i = t->size - 1; i >= 0; i--)
+		num = num * 256 + bytes[i];
+	nr_copy_bits = bit_sz + bits_offset;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	for (i = 0; i < t->size; i++)
+		num = num * 256 + bytes[i];
+	nr_copy_bits = t->size * 8 - bits_offset;
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+	left_shift_bits = 64 - nr_copy_bits;
+	right_shift_bits = 64 - bit_sz;
+
+	*value = (num << left_shift_bits) >> right_shift_bits;
+
+	return 0;
+}
+
+static int btf_dump_bitfield_check_zero(struct btf_dump *d,
+					const struct btf_type *t,
+					const void *data,
+					__u8 bits_offset,
+					__u8 bit_sz)
+{
+	__u64 check_num;
+	int err;
+
+	err = btf_dump_get_bitfield_value(d, t, data, bits_offset, bit_sz, &check_num);
+	if (err)
+		return err;
+	if (check_num == 0)
+		return -ENODATA;
+	return 0;
+}
+
+static int btf_dump_bitfield_data(struct btf_dump *d,
+				  const struct btf_type *t,
+				  const void *data,
+				  __u8 bits_offset,
+				  __u8 bit_sz)
+{
+	__u64 print_num;
+	int err;
+
+	err = btf_dump_get_bitfield_value(d, t, data, bits_offset, bit_sz, &print_num);
+	if (err)
+		return err;
+
+	btf_dump_type_values(d, "0x%llx", (unsigned long long)print_num);
+
+	return 0;
+}
+
+/* ints, floats and ptrs */
+static int btf_dump_base_type_check_zero(struct btf_dump *d,
+					 const struct btf_type *t,
+					 __u32 id,
+					 const void *data)
+{
+	static __u8 bytecmp[16] = {};
+	int nr_bytes;
+
+	/* For pointer types, pointer size is not defined on a per-type basis.
+	 * On dump creation however, we store the pointer size.
+	 */
+	if (btf_kind(t) == BTF_KIND_PTR)
+		nr_bytes = d->ptr_sz;
+	else
+		nr_bytes = t->size;
+
+	if (nr_bytes < 1 || nr_bytes > 16) {
+		pr_warn("unexpected size %d for id [%u]\n", nr_bytes, id);
+		return -EINVAL;
+	}
+
+	if (memcmp(data, bytecmp, nr_bytes) == 0)
+		return -ENODATA;
+	return 0;
+}
+
+static bool ptr_is_aligned(const struct btf *btf, __u32 type_id,
+			   const void *data)
+{
+	int alignment = btf__align_of(btf, type_id);
+
+	if (alignment == 0)
+		return false;
+
+	return ((uintptr_t)data) % alignment == 0;
+}
+
+static int btf_dump_int_data(struct btf_dump *d,
+			     const struct btf_type *t,
+			     __u32 type_id,
+			     const void *data,
+			     __u8 bits_offset)
+{
+	__u8 encoding = btf_int_encoding(t);
+	bool sign = encoding & BTF_INT_SIGNED;
+	char buf[16] __attribute__((aligned(16)));
+	int sz = t->size;
+
+	if (sz == 0 || sz > sizeof(buf)) {
+		pr_warn("unexpected size %d for id [%u]\n", sz, type_id);
+		return -EINVAL;
+	}
+
+	/* handle packed int data - accesses of integers not aligned on
+	 * int boundaries can cause problems on some platforms.
+	 */
+	if (!ptr_is_aligned(d->btf, type_id, data)) {
+		memcpy(buf, data, sz);
+		data = buf;
+	}
+
+	switch (sz) {
+	case 16: {
+		const __u64 *ints = data;
+		__u64 lsi, msi;
+
+		/* avoid use of __int128 as some 32-bit platforms do not
+		 * support it.
+		 */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+		lsi = ints[0];
+		msi = ints[1];
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+		lsi = ints[1];
+		msi = ints[0];
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+		if (msi == 0)
+			btf_dump_type_values(d, "0x%llx", (unsigned long long)lsi);
+		else
+			btf_dump_type_values(d, "0x%llx%016llx", (unsigned long long)msi,
+					     (unsigned long long)lsi);
+		break;
+	}
+	case 8:
+		if (sign)
+			btf_dump_type_values(d, "%lld", *(long long *)data);
+		else
+			btf_dump_type_values(d, "%llu", *(unsigned long long *)data);
+		break;
+	case 4:
+		if (sign)
+			btf_dump_type_values(d, "%d", *(__s32 *)data);
+		else
+			btf_dump_type_values(d, "%u", *(__u32 *)data);
+		break;
+	case 2:
+		if (sign)
+			btf_dump_type_values(d, "%d", *(__s16 *)data);
+		else
+			btf_dump_type_values(d, "%u", *(__u16 *)data);
+		break;
+	case 1:
+		if (d->typed_dump->is_array_char) {
+			/* check for null terminator */
+			if (d->typed_dump->is_array_terminated)
+				break;
+			if (*(char *)data == '\0') {
+				btf_dump_type_values(d, "'\\0'");
+				d->typed_dump->is_array_terminated = true;
+				break;
+			}
+			if (isprint(*(char *)data)) {
+				btf_dump_type_values(d, "'%c'", *(char *)data);
+				break;
+			}
+		}
+		if (sign)
+			btf_dump_type_values(d, "%d", *(__s8 *)data);
+		else
+			btf_dump_type_values(d, "%u", *(__u8 *)data);
+		break;
+	default:
+		pr_warn("unexpected sz %d for id [%u]\n", sz, type_id);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+union float_data {
+	long double ld;
+	double d;
+	float f;
+};
+
+static int btf_dump_float_data(struct btf_dump *d,
+			       const struct btf_type *t,
+			       __u32 type_id,
+			       const void *data)
+{
+	const union float_data *flp = data;
+	union float_data fl;
+	int sz = t->size;
+
+	/* handle unaligned data; copy to local union */
+	if (!ptr_is_aligned(d->btf, type_id, data)) {
+		memcpy(&fl, data, sz);
+		flp = &fl;
+	}
+
+	switch (sz) {
+	case 16:
+		btf_dump_type_values(d, "%Lf", flp->ld);
+		break;
+	case 8:
+		btf_dump_type_values(d, "%lf", flp->d);
+		break;
+	case 4:
+		btf_dump_type_values(d, "%f", flp->f);
+		break;
+	default:
+		pr_warn("unexpected size %d for id [%u]\n", sz, type_id);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int btf_dump_var_data(struct btf_dump *d,
+			     const struct btf_type *v,
+			     __u32 id,
+			     const void *data)
+{
+	enum btf_func_linkage linkage = btf_var(v)->linkage;
+	const struct btf_type *t;
+	const char *l;
+	__u32 type_id;
+
+	switch (linkage) {
+	case BTF_FUNC_STATIC:
+		l = "static ";
+		break;
+	case BTF_FUNC_EXTERN:
+		l = "extern ";
+		break;
+	case BTF_FUNC_GLOBAL:
+	default:
+		l = "";
+		break;
+	}
+
+	/* format of output here is [linkage] [type] [varname] = (type)value,
+	 * for example "static int cpu_profile_flip = (int)1"
+	 */
+	btf_dump_printf(d, "%s", l);
+	type_id = v->type;
+	t = btf__type_by_id(d->btf, type_id);
+	btf_dump_emit_type_cast(d, type_id, false);
+	btf_dump_printf(d, " %s = ", btf_name_of(d, v->name_off));
+	return btf_dump_dump_type_data(d, NULL, t, type_id, data, 0, 0);
+}
+
+static int btf_dump_string_data(struct btf_dump *d,
+				const struct btf_type *t,
+				__u32 id,
+				const void *data)
+{
+	const struct btf_array *array = btf_array(t);
+	const char *chars = data;
+	__u32 i;
+
+	/* Make sure it is a NUL-terminated string. */
+	for (i = 0; i < array->nelems; i++) {
+		if ((void *)(chars + i) >= d->typed_dump->data_end)
+			return -E2BIG;
+		if (chars[i] == '\0')
+			break;
+	}
+	if (i == array->nelems) {
+		/* The caller will print this as a regular array. */
+		return -EINVAL;
+	}
+
+	btf_dump_data_pfx(d);
+	btf_dump_printf(d, "\"");
+
+	for (i = 0; i < array->nelems; i++) {
+		char c = chars[i];
+
+		if (c == '\0') {
+			/*
+			 * When printing character arrays as strings, NUL bytes
+			 * are always treated as string terminators; they are
+			 * never printed.
+			 */
+			break;
+		}
+		if (isprint(c))
+			btf_dump_printf(d, "%c", c);
+		else
+			btf_dump_printf(d, "\\x%02x", (__u8)c);
+	}
+
+	btf_dump_printf(d, "\"");
+
+	return 0;
+}
+
+static int btf_dump_array_data(struct btf_dump *d,
+			       const struct btf_type *t,
+			       __u32 id,
+			       const void *data)
+{
+	const struct btf_array *array = btf_array(t);
+	const struct btf_type *elem_type;
+	__u32 i, elem_type_id;
+	__s64 elem_size;
+	bool is_array_member;
+	bool is_array_terminated;
+
+	elem_type_id = array->type;
+	elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
+	elem_size = btf__resolve_size(d->btf, elem_type_id);
+	if (elem_size <= 0) {
+		pr_warn("unexpected elem size %zd for array type [%u]\n",
+			(ssize_t)elem_size, id);
+		return -EINVAL;
+	}
+
+	if (btf_is_int(elem_type)) {
+		/*
+		 * BTF_INT_CHAR encoding never seems to be set for
+		 * char arrays, so if size is 1 and element is
+		 * printable as a char, we'll do that.
+		 */
+		if (elem_size == 1) {
+			if (d->typed_dump->emit_strings &&
+			    btf_dump_string_data(d, t, id, data) == 0) {
+				return 0;
+			}
+			d->typed_dump->is_array_char = true;
+		}
+	}
+
+	/* note that we increment depth before calling btf_dump_print() below;
+	 * this is intentional.  btf_dump_data_newline() will not print a
+	 * newline for depth 0 (since this leaves us with trailing newlines
+	 * at the end of typed display), so depth is incremented first.
+	 * For similar reasons, we decrement depth before showing the closing
+	 * parenthesis.
+	 */
+	d->typed_dump->depth++;
+	btf_dump_printf(d, "[%s", btf_dump_data_newline(d));
+
+	/* may be a multidimensional array, so store current "is array member"
+	 * status so we can restore it correctly later.
+	 */
+	is_array_member = d->typed_dump->is_array_member;
+	d->typed_dump->is_array_member = true;
+	is_array_terminated = d->typed_dump->is_array_terminated;
+	d->typed_dump->is_array_terminated = false;
+	for (i = 0; i < array->nelems; i++, data += elem_size) {
+		if (d->typed_dump->is_array_terminated)
+			break;
+		btf_dump_dump_type_data(d, NULL, elem_type, elem_type_id, data, 0, 0);
+	}
+	d->typed_dump->is_array_member = is_array_member;
+	d->typed_dump->is_array_terminated = is_array_terminated;
+	d->typed_dump->depth--;
+	btf_dump_data_pfx(d);
+	btf_dump_type_values(d, "]");
+
+	return 0;
+}
+
+static int btf_dump_struct_data(struct btf_dump *d,
+				const struct btf_type *t,
+				__u32 id,
+				const void *data)
+{
+	const struct btf_member *m = btf_members(t);
+	__u32 n = btf_vlen(t);
+	int i, err = 0;
+
+	/* note that we increment depth before calling btf_dump_print() below;
+	 * this is intentional.  btf_dump_data_newline() will not print a
+	 * newline for depth 0 (since this leaves us with trailing newlines
+	 * at the end of typed display), so depth is incremented first.
+	 * For similar reasons, we decrement depth before showing the closing
+	 * parenthesis.
+	 */
+	d->typed_dump->depth++;
+	btf_dump_printf(d, "{%s", btf_dump_data_newline(d));
+
+	for (i = 0; i < n; i++, m++) {
+		const struct btf_type *mtype;
+		const char *mname;
+		__u32 moffset;
+		__u8 bit_sz;
+
+		mtype = btf__type_by_id(d->btf, m->type);
+		mname = btf_name_of(d, m->name_off);
+		moffset = btf_member_bit_offset(t, i);
+
+		bit_sz = btf_member_bitfield_size(t, i);
+		err = btf_dump_dump_type_data(d, mname, mtype, m->type, data + moffset / 8,
+					      moffset % 8, bit_sz);
+		if (err < 0)
+			return err;
+	}
+	d->typed_dump->depth--;
+	btf_dump_data_pfx(d);
+	btf_dump_type_values(d, "}");
+	return err;
+}
+
+union ptr_data {
+	unsigned int p;
+	unsigned long long lp;
+};
+
+static int btf_dump_ptr_data(struct btf_dump *d,
+			      const struct btf_type *t,
+			      __u32 id,
+			      const void *data)
+{
+	if (ptr_is_aligned(d->btf, id, data) && d->ptr_sz == sizeof(void *)) {
+		btf_dump_type_values(d, "%p", *(void **)data);
+	} else {
+		union ptr_data pt;
+
+		memcpy(&pt, data, d->ptr_sz);
+		if (d->ptr_sz == 4)
+			btf_dump_type_values(d, "0x%x", pt.p);
+		else
+			btf_dump_type_values(d, "0x%llx", pt.lp);
+	}
+	return 0;
+}
+
+static int btf_dump_get_enum_value(struct btf_dump *d,
+				   const struct btf_type *t,
+				   const void *data,
+				   __u32 id,
+				   __s64 *value)
+{
+	bool is_signed = btf_kflag(t);
+
+	if (!ptr_is_aligned(d->btf, id, data)) {
+		__u64 val;
+		int err;
+
+		err = btf_dump_get_bitfield_value(d, t, data, 0, 0, &val);
+		if (err)
+			return err;
+		*value = (__s64)val;
+		return 0;
+	}
+
+	switch (t->size) {
+	case 8:
+		*value = *(__s64 *)data;
+		return 0;
+	case 4:
+		*value = is_signed ? (__s64)*(__s32 *)data : *(__u32 *)data;
+		return 0;
+	case 2:
+		*value = is_signed ? *(__s16 *)data : *(__u16 *)data;
+		return 0;
+	case 1:
+		*value = is_signed ? *(__s8 *)data : *(__u8 *)data;
+		return 0;
+	default:
+		pr_warn("unexpected size %u for enum, id:[%u]\n", t->size, id);
+		return -EINVAL;
+	}
+}
+
+static int btf_dump_enum_data(struct btf_dump *d,
+			      const struct btf_type *t,
+			      __u32 id,
+			      const void *data)
+{
+	bool is_signed;
+	__s64 value;
+	int i, err;
+
+	err = btf_dump_get_enum_value(d, t, data, id, &value);
+	if (err)
+		return err;
+
+	is_signed = btf_kflag(t);
+	if (btf_is_enum(t)) {
+		const struct btf_enum *e;
+
+		for (i = 0, e = btf_enum(t); i < btf_vlen(t); i++, e++) {
+			if (value != e->val)
+				continue;
+			btf_dump_type_values(d, "%s", btf_name_of(d, e->name_off));
+			return 0;
+		}
+
+		btf_dump_type_values(d, is_signed ? "%d" : "%u", value);
+	} else {
+		const struct btf_enum64 *e;
+
+		for (i = 0, e = btf_enum64(t); i < btf_vlen(t); i++, e++) {
+			if (value != btf_enum64_value(e))
+				continue;
+			btf_dump_type_values(d, "%s", btf_name_of(d, e->name_off));
+			return 0;
+		}
+
+		btf_dump_type_values(d, is_signed ? "%lldLL" : "%lluULL",
+				     (unsigned long long)value);
+	}
+	return 0;
+}
+
+static int btf_dump_datasec_data(struct btf_dump *d,
+				 const struct btf_type *t,
+				 __u32 id,
+				 const void *data)
+{
+	const struct btf_var_secinfo *vsi;
+	const struct btf_type *var;
+	__u32 i;
+	int err;
+
+	btf_dump_type_values(d, "SEC(\"%s\") ", btf_name_of(d, t->name_off));
+
+	for (i = 0, vsi = btf_var_secinfos(t); i < btf_vlen(t); i++, vsi++) {
+		var = btf__type_by_id(d->btf, vsi->type);
+		err = btf_dump_dump_type_data(d, NULL, var, vsi->type, data + vsi->offset, 0, 0);
+		if (err < 0)
+			return err;
+		btf_dump_printf(d, ";");
+	}
+	return 0;
+}
+
+/* return size of type, or if base type overflows, return -E2BIG. */
+static int btf_dump_type_data_check_overflow(struct btf_dump *d,
+					     const struct btf_type *t,
+					     __u32 id,
+					     const void *data,
+					     __u8 bits_offset,
+					     __u8 bit_sz)
+{
+	__s64 size;
+
+	if (bit_sz) {
+		/* bits_offset is at most 7. bit_sz is at most 128. */
+		__u8 nr_bytes = (bits_offset + bit_sz + 7) / 8;
+
+		/* When bit_sz is non zero, it is called from
+		 * btf_dump_struct_data() where it only cares about
+		 * negative error value.
+		 * Return nr_bytes in success case to make it
+		 * consistent as the regular integer case below.
+		 */
+		return data + nr_bytes > d->typed_dump->data_end ? -E2BIG : nr_bytes;
+	}
+
+	size = btf__resolve_size(d->btf, id);
+
+	if (size < 0 || size >= INT_MAX) {
+		pr_warn("unexpected size [%zu] for id [%u]\n",
+			(size_t)size, id);
+		return -EINVAL;
+	}
+
+	/* Only do overflow checking for base types; we do not want to
+	 * avoid showing part of a struct, union or array, even if we
+	 * do not have enough data to show the full object.  By
+	 * restricting overflow checking to base types we can ensure
+	 * that partial display succeeds, while avoiding overflowing
+	 * and using bogus data for display.
+	 */
+	t = skip_mods_and_typedefs(d->btf, id, NULL);
+	if (!t) {
+		pr_warn("unexpected error skipping mods/typedefs for id [%u]\n",
+			id);
+		return -EINVAL;
+	}
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_INT:
+	case BTF_KIND_FLOAT:
+	case BTF_KIND_PTR:
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		if (data + bits_offset / 8 + size > d->typed_dump->data_end)
+			return -E2BIG;
+		break;
+	default:
+		break;
+	}
+	return (int)size;
+}
+
+static int btf_dump_type_data_check_zero(struct btf_dump *d,
+					 const struct btf_type *t,
+					 __u32 id,
+					 const void *data,
+					 __u8 bits_offset,
+					 __u8 bit_sz)
+{
+	__s64 value;
+	int i, err;
+
+	/* toplevel exceptions; we show zero values if
+	 * - we ask for them (emit_zeros)
+	 * - if we are at top-level so we see "struct empty { }"
+	 * - or if we are an array member and the array is non-empty and
+	 *   not a char array; we don't want to be in a situation where we
+	 *   have an integer array 0, 1, 0, 1 and only show non-zero values.
+	 *   If the array contains zeroes only, or is a char array starting
+	 *   with a '\0', the array-level check_zero() will prevent showing it;
+	 *   we are concerned with determining zero value at the array member
+	 *   level here.
+	 */
+	if (d->typed_dump->emit_zeroes || d->typed_dump->depth == 0 ||
+	    (d->typed_dump->is_array_member &&
+	     !d->typed_dump->is_array_char))
+		return 0;
+
+	t = skip_mods_and_typedefs(d->btf, id, NULL);
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_INT:
+		if (bit_sz)
+			return btf_dump_bitfield_check_zero(d, t, data, bits_offset, bit_sz);
+		return btf_dump_base_type_check_zero(d, t, id, data);
+	case BTF_KIND_FLOAT:
+	case BTF_KIND_PTR:
+		return btf_dump_base_type_check_zero(d, t, id, data);
+	case BTF_KIND_ARRAY: {
+		const struct btf_array *array = btf_array(t);
+		const struct btf_type *elem_type;
+		__u32 elem_type_id, elem_size;
+		bool ischar;
+
+		elem_type_id = array->type;
+		elem_size = btf__resolve_size(d->btf, elem_type_id);
+		elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
+
+		ischar = btf_is_int(elem_type) && elem_size == 1;
+
+		/* check all elements; if _any_ element is nonzero, all
+		 * of array is displayed.  We make an exception however
+		 * for char arrays where the first element is 0; these
+		 * are considered zeroed also, even if later elements are
+		 * non-zero because the string is terminated.
+		 */
+		for (i = 0; i < array->nelems; i++) {
+			if (i == 0 && ischar && *(char *)data == 0)
+				return -ENODATA;
+			err = btf_dump_type_data_check_zero(d, elem_type,
+							    elem_type_id,
+							    data +
+							    (i * elem_size),
+							    bits_offset, 0);
+			if (err != -ENODATA)
+				return err;
+		}
+		return -ENODATA;
+	}
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m = btf_members(t);
+		__u32 n = btf_vlen(t);
+
+		/* if any struct/union member is non-zero, the struct/union
+		 * is considered non-zero and dumped.
+		 */
+		for (i = 0; i < n; i++, m++) {
+			const struct btf_type *mtype;
+			__u32 moffset;
+
+			mtype = btf__type_by_id(d->btf, m->type);
+			moffset = btf_member_bit_offset(t, i);
+
+			/* btf_int_bits() does not store member bitfield size;
+			 * bitfield size needs to be stored here so int display
+			 * of member can retrieve it.
+			 */
+			bit_sz = btf_member_bitfield_size(t, i);
+			err = btf_dump_type_data_check_zero(d, mtype, m->type, data + moffset / 8,
+							    moffset % 8, bit_sz);
+			if (err != ENODATA)
+				return err;
+		}
+		return -ENODATA;
+	}
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		err = btf_dump_get_enum_value(d, t, data, id, &value);
+		if (err)
+			return err;
+		if (value == 0)
+			return -ENODATA;
+		return 0;
+	default:
+		return 0;
+	}
+}
+
+/* returns size of data dumped, or error. */
+static int btf_dump_dump_type_data(struct btf_dump *d,
+				   const char *fname,
+				   const struct btf_type *t,
+				   __u32 id,
+				   const void *data,
+				   __u8 bits_offset,
+				   __u8 bit_sz)
+{
+	int size, err = 0;
+
+	size = btf_dump_type_data_check_overflow(d, t, id, data, bits_offset, bit_sz);
+	if (size < 0)
+		return size;
+	err = btf_dump_type_data_check_zero(d, t, id, data, bits_offset, bit_sz);
+	if (err) {
+		/* zeroed data is expected and not an error, so simply skip
+		 * dumping such data.  Record other errors however.
+		 */
+		if (err == -ENODATA)
+			return size;
+		return err;
+	}
+	btf_dump_data_pfx(d);
+
+	if (!d->typed_dump->skip_names) {
+		if (fname && strlen(fname) > 0)
+			btf_dump_printf(d, ".%s = ", fname);
+		btf_dump_emit_type_cast(d, id, true);
+	}
+
+	t = skip_mods_and_typedefs(d->btf, id, NULL);
+
+	switch (btf_kind(t)) {
+	case BTF_KIND_UNKN:
+	case BTF_KIND_FWD:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_FUNC_PROTO:
+	case BTF_KIND_DECL_TAG:
+		err = btf_dump_unsupported_data(d, t, id);
+		break;
+	case BTF_KIND_INT:
+		if (bit_sz)
+			err = btf_dump_bitfield_data(d, t, data, bits_offset, bit_sz);
+		else
+			err = btf_dump_int_data(d, t, id, data, bits_offset);
+		break;
+	case BTF_KIND_FLOAT:
+		err = btf_dump_float_data(d, t, id, data);
+		break;
+	case BTF_KIND_PTR:
+		err = btf_dump_ptr_data(d, t, id, data);
+		break;
+	case BTF_KIND_ARRAY:
+		err = btf_dump_array_data(d, t, id, data);
+		break;
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+		err = btf_dump_struct_data(d, t, id, data);
+		break;
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		/* handle bitfield and int enum values */
+		if (bit_sz) {
+			__u64 print_num;
+			__s64 enum_val;
+
+			err = btf_dump_get_bitfield_value(d, t, data, bits_offset, bit_sz,
+							  &print_num);
+			if (err)
+				break;
+			enum_val = (__s64)print_num;
+			err = btf_dump_enum_data(d, t, id, &enum_val);
+		} else
+			err = btf_dump_enum_data(d, t, id, data);
+		break;
+	case BTF_KIND_VAR:
+		err = btf_dump_var_data(d, t, id, data);
+		break;
+	case BTF_KIND_DATASEC:
+		err = btf_dump_datasec_data(d, t, id, data);
+		break;
+	default:
+		pr_warn("unexpected kind [%u] for id [%u]\n",
+			BTF_INFO_KIND(t->info), id);
+		return -EINVAL;
+	}
+	if (err < 0)
+		return err;
+	return size;
+}
+
+int btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
+			     const void *data, size_t data_sz,
+			     const struct btf_dump_type_data_opts *opts)
+{
+	struct btf_dump_data typed_dump = {};
+	const struct btf_type *t;
+	int ret;
+
+	if (!OPTS_VALID(opts, btf_dump_type_data_opts))
+		return libbpf_err(-EINVAL);
+
+	t = btf__type_by_id(d->btf, id);
+	if (!t)
+		return libbpf_err(-ENOENT);
+
+	d->typed_dump = &typed_dump;
+	d->typed_dump->data_end = data + data_sz;
+	d->typed_dump->indent_lvl = OPTS_GET(opts, indent_level, 0);
+
+	/* default indent string is a tab */
+	if (!OPTS_GET(opts, indent_str, NULL))
+		d->typed_dump->indent_str[0] = '\t';
+	else
+		libbpf_strlcpy(d->typed_dump->indent_str, opts->indent_str,
+			       sizeof(d->typed_dump->indent_str));
+
+	d->typed_dump->compact = OPTS_GET(opts, compact, false);
+	d->typed_dump->skip_names = OPTS_GET(opts, skip_names, false);
+	d->typed_dump->emit_zeroes = OPTS_GET(opts, emit_zeroes, false);
+	d->typed_dump->emit_strings = OPTS_GET(opts, emit_strings, false);
+
+	ret = btf_dump_dump_type_data(d, NULL, t, id, data, 0, 0);
+
+	d->typed_dump = NULL;
+
+	return libbpf_err(ret);
+}
diff --git a/tools/lib/bpf/btf_iter.c b/tools/lib/bpf/btf_iter.c
new file mode 100644
index 000000000..9a6c822c2
--- /dev/null
+++ b/tools/lib/bpf/btf_iter.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2021 Facebook */
+/* Copyright (c) 2024, Oracle and/or its affiliates. */
+
+#ifdef __KERNEL__
+#include <linux/bpf.h>
+#include <linux/btf.h>
+
+#define btf_var_secinfos(t)	(struct btf_var_secinfo *)btf_type_var_secinfo(t)
+
+#else
+#include "btf.h"
+#include "libbpf_internal.h"
+#endif
+
+int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t,
+			enum btf_field_iter_kind iter_kind)
+{
+	it->p = NULL;
+	it->m_idx = -1;
+	it->off_idx = 0;
+	it->vlen = 0;
+
+	switch (iter_kind) {
+	case BTF_FIELD_ITER_IDS:
+		switch (btf_kind(t)) {
+		case BTF_KIND_UNKN:
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+			it->desc = (struct btf_field_desc) {};
+			break;
+		case BTF_KIND_FWD:
+		case BTF_KIND_CONST:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_PTR:
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_FUNC:
+		case BTF_KIND_VAR:
+		case BTF_KIND_DECL_TAG:
+		case BTF_KIND_TYPE_TAG:
+			it->desc = (struct btf_field_desc) { 1, {offsetof(struct btf_type, type)} };
+			break;
+		case BTF_KIND_ARRAY:
+			it->desc = (struct btf_field_desc) {
+				2, {sizeof(struct btf_type) + offsetof(struct btf_array, type),
+				sizeof(struct btf_type) + offsetof(struct btf_array, index_type)}
+			};
+			break;
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			it->desc = (struct btf_field_desc) {
+				0, {},
+				sizeof(struct btf_member),
+				1, {offsetof(struct btf_member, type)}
+			};
+			break;
+		case BTF_KIND_FUNC_PROTO:
+			it->desc = (struct btf_field_desc) {
+				1, {offsetof(struct btf_type, type)},
+				sizeof(struct btf_param),
+				1, {offsetof(struct btf_param, type)}
+			};
+			break;
+		case BTF_KIND_DATASEC:
+			it->desc = (struct btf_field_desc) {
+				0, {},
+				sizeof(struct btf_var_secinfo),
+				1, {offsetof(struct btf_var_secinfo, type)}
+			};
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case BTF_FIELD_ITER_STRS:
+		switch (btf_kind(t)) {
+		case BTF_KIND_UNKN:
+			it->desc = (struct btf_field_desc) {};
+			break;
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_FWD:
+		case BTF_KIND_ARRAY:
+		case BTF_KIND_CONST:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_PTR:
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_FUNC:
+		case BTF_KIND_VAR:
+		case BTF_KIND_DECL_TAG:
+		case BTF_KIND_TYPE_TAG:
+		case BTF_KIND_DATASEC:
+			it->desc = (struct btf_field_desc) {
+				1, {offsetof(struct btf_type, name_off)}
+			};
+			break;
+		case BTF_KIND_ENUM:
+			it->desc = (struct btf_field_desc) {
+				1, {offsetof(struct btf_type, name_off)},
+				sizeof(struct btf_enum),
+				1, {offsetof(struct btf_enum, name_off)}
+			};
+			break;
+		case BTF_KIND_ENUM64:
+			it->desc = (struct btf_field_desc) {
+				1, {offsetof(struct btf_type, name_off)},
+				sizeof(struct btf_enum64),
+				1, {offsetof(struct btf_enum64, name_off)}
+			};
+			break;
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			it->desc = (struct btf_field_desc) {
+				1, {offsetof(struct btf_type, name_off)},
+				sizeof(struct btf_member),
+				1, {offsetof(struct btf_member, name_off)}
+			};
+			break;
+		case BTF_KIND_FUNC_PROTO:
+			it->desc = (struct btf_field_desc) {
+				1, {offsetof(struct btf_type, name_off)},
+				sizeof(struct btf_param),
+				1, {offsetof(struct btf_param, name_off)}
+			};
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (it->desc.m_sz)
+		it->vlen = btf_vlen(t);
+
+	it->p = t;
+	return 0;
+}
+
+__u32 *btf_field_iter_next(struct btf_field_iter *it)
+{
+	if (!it->p)
+		return NULL;
+
+	if (it->m_idx < 0) {
+		if (it->off_idx < it->desc.t_off_cnt)
+			return it->p + it->desc.t_offs[it->off_idx++];
+		/* move to per-member iteration */
+		it->m_idx = 0;
+		it->p += sizeof(struct btf_type);
+		it->off_idx = 0;
+	}
+
+	/* if type doesn't have members, stop */
+	if (it->desc.m_sz == 0) {
+		it->p = NULL;
+		return NULL;
+	}
+
+	if (it->off_idx >= it->desc.m_off_cnt) {
+		/* exhausted this member's fields, go to the next member */
+		it->m_idx++;
+		it->p += it->desc.m_sz;
+		it->off_idx = 0;
+	}
+
+	if (it->m_idx < it->vlen)
+		return it->p + it->desc.m_offs[it->off_idx++];
+
+	it->p = NULL;
+	return NULL;
+}
diff --git a/tools/lib/bpf/btf_relocate.c b/tools/lib/bpf/btf_relocate.c
new file mode 100644
index 000000000..df5fa4bd8
--- /dev/null
+++ b/tools/lib/bpf/btf_relocate.c
@@ -0,0 +1,519 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2024, Oracle and/or its affiliates. */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#ifdef __KERNEL__
+#include <linux/bpf.h>
+#include <linux/bsearch.h>
+#include <linux/btf.h>
+#include <linux/sort.h>
+#include <linux/string.h>
+#include <linux/bpf_verifier.h>
+
+#define btf_type_by_id				(struct btf_type *)btf_type_by_id
+#define btf__type_cnt				btf_nr_types
+#define btf__base_btf				btf_base_btf
+#define btf__name_by_offset			btf_name_by_offset
+#define btf__str_by_offset			btf_str_by_offset
+#define btf_kflag				btf_type_kflag
+
+#define calloc(nmemb, sz)			kvcalloc(nmemb, sz, GFP_KERNEL | __GFP_NOWARN)
+#define free(ptr)				kvfree(ptr)
+#define qsort(base, num, sz, cmp)		sort(base, num, sz, cmp, NULL)
+
+#else
+
+#include "btf.h"
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+#endif /* __KERNEL__ */
+
+struct btf;
+
+struct btf_relocate {
+	struct btf *btf;
+	const struct btf *base_btf;
+	const struct btf *dist_base_btf;
+	unsigned int nr_base_types;
+	unsigned int nr_split_types;
+	unsigned int nr_dist_base_types;
+	int dist_str_len;
+	int base_str_len;
+	__u32 *id_map;
+	__u32 *str_map;
+};
+
+/* Set temporarily in relocation id_map if distilled base struct/union is
+ * embedded in a split BTF struct/union; in such a case, size information must
+ * match between distilled base BTF and base BTF representation of type.
+ */
+#define BTF_IS_EMBEDDED ((__u32)-1)
+
+/* <name, size, id> triple used in sorting/searching distilled base BTF. */
+struct btf_name_info {
+	const char *name;
+	/* set when search requires a size match */
+	bool needs_size: 1;
+	unsigned int size: 31;
+	__u32 id;
+};
+
+static int btf_relocate_rewrite_type_id(struct btf_relocate *r, __u32 i)
+{
+	struct btf_type *t = btf_type_by_id(r->btf, i);
+	struct btf_field_iter it;
+	__u32 *id;
+	int err;
+
+	err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);
+	if (err)
+		return err;
+
+	while ((id = btf_field_iter_next(&it)))
+		*id = r->id_map[*id];
+	return 0;
+}
+
+/* Simple string comparison used for sorting within BTF, since all distilled
+ * types are named.  If strings match, and size is non-zero for both elements
+ * fall back to using size for ordering.
+ */
+static int cmp_btf_name_size(const void *n1, const void *n2)
+{
+	const struct btf_name_info *ni1 = n1;
+	const struct btf_name_info *ni2 = n2;
+	int name_diff = strcmp(ni1->name, ni2->name);
+
+	if (!name_diff && ni1->needs_size && ni2->needs_size)
+		return ni2->size - ni1->size;
+	return name_diff;
+}
+
+/* Binary search with a small twist; find leftmost element that matches
+ * so that we can then iterate through all exact matches.  So for example
+ * searching { "a", "bb", "bb", "c" }  we would always match on the
+ * leftmost "bb".
+ */
+static struct btf_name_info *search_btf_name_size(struct btf_name_info *key,
+						  struct btf_name_info *vals,
+						  int nelems)
+{
+	struct btf_name_info *ret = NULL;
+	int high = nelems - 1;
+	int low = 0;
+
+	while (low <= high) {
+		int mid = (low + high)/2;
+		struct btf_name_info *val = &vals[mid];
+		int diff = cmp_btf_name_size(key, val);
+
+		if (diff == 0)
+			ret = val;
+		/* even if found, keep searching for leftmost match */
+		if (diff <= 0)
+			high = mid - 1;
+		else
+			low = mid + 1;
+	}
+	return ret;
+}
+
+/* If a member of a split BTF struct/union refers to a base BTF
+ * struct/union, mark that struct/union id temporarily in the id_map
+ * with BTF_IS_EMBEDDED.  Members can be const/restrict/volatile/typedef
+ * reference types, but if a pointer is encountered, the type is no longer
+ * considered embedded.
+ */
+static int btf_mark_embedded_composite_type_ids(struct btf_relocate *r, __u32 i)
+{
+	struct btf_type *t = btf_type_by_id(r->btf, i);
+	struct btf_field_iter it;
+	__u32 *id;
+	int err;
+
+	if (!btf_is_composite(t))
+		return 0;
+
+	err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);
+	if (err)
+		return err;
+
+	while ((id = btf_field_iter_next(&it))) {
+		__u32 next_id = *id;
+
+		while (next_id) {
+			t = btf_type_by_id(r->btf, next_id);
+			switch (btf_kind(t)) {
+			case BTF_KIND_CONST:
+			case BTF_KIND_RESTRICT:
+			case BTF_KIND_VOLATILE:
+			case BTF_KIND_TYPEDEF:
+			case BTF_KIND_TYPE_TAG:
+				next_id = t->type;
+				break;
+			case BTF_KIND_ARRAY: {
+				struct btf_array *a = btf_array(t);
+
+				next_id = a->type;
+				break;
+			}
+			case BTF_KIND_STRUCT:
+			case BTF_KIND_UNION:
+				if (next_id < r->nr_dist_base_types)
+					r->id_map[next_id] = BTF_IS_EMBEDDED;
+				next_id = 0;
+				break;
+			default:
+				next_id = 0;
+				break;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/* Build a map from distilled base BTF ids to base BTF ids. To do so, iterate
+ * through base BTF looking up distilled type (using binary search) equivalents.
+ */
+static int btf_relocate_map_distilled_base(struct btf_relocate *r)
+{
+	struct btf_name_info *info, *info_end;
+	struct btf_type *base_t, *dist_t;
+	__u8 *base_name_cnt = NULL;
+	int err = 0;
+	__u32 id;
+
+	/* generate a sort index array of name/type ids sorted by name for
+	 * distilled base BTF to speed name-based lookups.
+	 */
+	info = calloc(r->nr_dist_base_types, sizeof(*info));
+	if (!info) {
+		err = -ENOMEM;
+		goto done;
+	}
+	info_end = info + r->nr_dist_base_types;
+	for (id = 0; id < r->nr_dist_base_types; id++) {
+		dist_t = btf_type_by_id(r->dist_base_btf, id);
+		info[id].name = btf__name_by_offset(r->dist_base_btf, dist_t->name_off);
+		info[id].id = id;
+		info[id].size = dist_t->size;
+		info[id].needs_size = true;
+	}
+	qsort(info, r->nr_dist_base_types, sizeof(*info), cmp_btf_name_size);
+
+	/* Mark distilled base struct/union members of split BTF structs/unions
+	 * in id_map with BTF_IS_EMBEDDED; this signals that these types
+	 * need to match both name and size, otherwise embedding the base
+	 * struct/union in the split type is invalid.
+	 */
+	for (id = r->nr_dist_base_types; id < r->nr_dist_base_types + r->nr_split_types; id++) {
+		err = btf_mark_embedded_composite_type_ids(r, id);
+		if (err)
+			goto done;
+	}
+
+	/* Collect name counts for composite types in base BTF.  If multiple
+	 * instances of a struct/union of the same name exist, we need to use
+	 * size to determine which to map to since name alone is ambiguous.
+	 */
+	base_name_cnt = calloc(r->base_str_len, sizeof(*base_name_cnt));
+	if (!base_name_cnt) {
+		err = -ENOMEM;
+		goto done;
+	}
+	for (id = 1; id < r->nr_base_types; id++) {
+		base_t = btf_type_by_id(r->base_btf, id);
+		if (!btf_is_composite(base_t) || !base_t->name_off)
+			continue;
+		if (base_name_cnt[base_t->name_off] < 255)
+			base_name_cnt[base_t->name_off]++;
+	}
+
+	/* Now search base BTF for matching distilled base BTF types. */
+	for (id = 1; id < r->nr_base_types; id++) {
+		struct btf_name_info *dist_info, base_info = {};
+		int dist_kind, base_kind;
+
+		base_t = btf_type_by_id(r->base_btf, id);
+		/* distilled base consists of named types only. */
+		if (!base_t->name_off)
+			continue;
+		base_kind = btf_kind(base_t);
+		base_info.id = id;
+		base_info.name = btf__name_by_offset(r->base_btf, base_t->name_off);
+		switch (base_kind) {
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_ENUM64:
+			/* These types should match both name and size */
+			base_info.needs_size = true;
+			base_info.size = base_t->size;
+			break;
+		case BTF_KIND_FWD:
+			/* No size considerations for fwds. */
+			break;
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+			/* Size only needs to be used for struct/union if there
+			 * are multiple types in base BTF with the same name.
+			 * If there are multiple _distilled_ types with the same
+			 * name (a very unlikely scenario), that doesn't matter
+			 * unless corresponding _base_ types to match them are
+			 * missing.
+			 */
+			base_info.needs_size = base_name_cnt[base_t->name_off] > 1;
+			base_info.size = base_t->size;
+			break;
+		default:
+			continue;
+		}
+		/* iterate over all matching distilled base types */
+		for (dist_info = search_btf_name_size(&base_info, info, r->nr_dist_base_types);
+		     dist_info != NULL && dist_info < info_end &&
+		     cmp_btf_name_size(&base_info, dist_info) == 0;
+		     dist_info++) {
+			if (!dist_info->id || dist_info->id >= r->nr_dist_base_types) {
+				pr_warn("base BTF id [%u] maps to invalid distilled base BTF id [%u]\n",
+					id, dist_info->id);
+				err = -EINVAL;
+				goto done;
+			}
+			dist_t = btf_type_by_id(r->dist_base_btf, dist_info->id);
+			dist_kind = btf_kind(dist_t);
+
+			/* Validate that the found distilled type is compatible.
+			 * Do not error out on mismatch as another match may
+			 * occur for an identically-named type.
+			 */
+			switch (dist_kind) {
+			case BTF_KIND_FWD:
+				switch (base_kind) {
+				case BTF_KIND_FWD:
+					if (btf_kflag(dist_t) != btf_kflag(base_t))
+						continue;
+					break;
+				case BTF_KIND_STRUCT:
+					if (btf_kflag(base_t))
+						continue;
+					break;
+				case BTF_KIND_UNION:
+					if (!btf_kflag(base_t))
+						continue;
+					break;
+				default:
+					continue;
+				}
+				break;
+			case BTF_KIND_INT:
+				if (dist_kind != base_kind ||
+				    btf_int_encoding(base_t) != btf_int_encoding(dist_t))
+					continue;
+				break;
+			case BTF_KIND_FLOAT:
+				if (dist_kind != base_kind)
+					continue;
+				break;
+			case BTF_KIND_ENUM:
+				/* ENUM and ENUM64 are encoded as sized ENUM in
+				 * distilled base BTF.
+				 */
+				if (base_kind != dist_kind && base_kind != BTF_KIND_ENUM64)
+					continue;
+				break;
+			case BTF_KIND_STRUCT:
+			case BTF_KIND_UNION:
+				/* size verification is required for embedded
+				 * struct/unions.
+				 */
+				if (r->id_map[dist_info->id] == BTF_IS_EMBEDDED &&
+				    base_t->size != dist_t->size)
+					continue;
+				break;
+			default:
+				continue;
+			}
+			if (r->id_map[dist_info->id] &&
+			    r->id_map[dist_info->id] != BTF_IS_EMBEDDED) {
+				/* we already have a match; this tells us that
+				 * multiple base types of the same name
+				 * have the same size, since for cases where
+				 * multiple types have the same name we match
+				 * on name and size.  In this case, we have
+				 * no way of determining which to relocate
+				 * to in base BTF, so error out.
+				 */
+				pr_warn("distilled base BTF type '%s' [%u], size %u has multiple candidates of the same size (ids [%u, %u]) in base BTF\n",
+					base_info.name, dist_info->id,
+					base_t->size, id, r->id_map[dist_info->id]);
+				err = -EINVAL;
+				goto done;
+			}
+			/* map id and name */
+			r->id_map[dist_info->id] = id;
+			r->str_map[dist_t->name_off] = base_t->name_off;
+		}
+	}
+	/* ensure all distilled BTF ids now have a mapping... */
+	for (id = 1; id < r->nr_dist_base_types; id++) {
+		const char *name;
+
+		if (r->id_map[id] && r->id_map[id] != BTF_IS_EMBEDDED)
+			continue;
+		dist_t = btf_type_by_id(r->dist_base_btf, id);
+		name = btf__name_by_offset(r->dist_base_btf, dist_t->name_off);
+		pr_warn("distilled base BTF type '%s' [%u] is not mapped to base BTF id\n",
+			name, id);
+		err = -EINVAL;
+		break;
+	}
+done:
+	free(base_name_cnt);
+	free(info);
+	return err;
+}
+
+/* distilled base should only have named int/float/enum/fwd/struct/union types. */
+static int btf_relocate_validate_distilled_base(struct btf_relocate *r)
+{
+	unsigned int i;
+
+	for (i = 1; i < r->nr_dist_base_types; i++) {
+		struct btf_type *t = btf_type_by_id(r->dist_base_btf, i);
+		int kind = btf_kind(t);
+
+		switch (kind) {
+		case BTF_KIND_INT:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+		case BTF_KIND_FWD:
+			if (t->name_off)
+				break;
+			pr_warn("type [%u], kind [%d] is invalid for distilled base BTF; it is anonymous\n",
+				i, kind);
+			return -EINVAL;
+		default:
+			pr_warn("type [%u] in distilled based BTF has unexpected kind [%d]\n",
+				i, kind);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static int btf_relocate_rewrite_strs(struct btf_relocate *r, __u32 i)
+{
+	struct btf_type *t = btf_type_by_id(r->btf, i);
+	struct btf_field_iter it;
+	__u32 *str_off;
+	int off, err;
+
+	err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);
+	if (err)
+		return err;
+
+	while ((str_off = btf_field_iter_next(&it))) {
+		if (!*str_off)
+			continue;
+		if (*str_off >= r->dist_str_len) {
+			*str_off += r->base_str_len - r->dist_str_len;
+		} else {
+			off = r->str_map[*str_off];
+			if (!off) {
+				pr_warn("string '%s' [offset %u] is not mapped to base BTF\n",
+					btf__str_by_offset(r->btf, off), *str_off);
+				return -ENOENT;
+			}
+			*str_off = off;
+		}
+	}
+	return 0;
+}
+
+/* If successful, output of relocation is updated BTF with base BTF pointing
+ * at base_btf, and type ids, strings adjusted accordingly.
+ */
+int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map)
+{
+	unsigned int nr_types = btf__type_cnt(btf);
+	const struct btf_header *dist_base_hdr;
+	const struct btf_header *base_hdr;
+	struct btf_relocate r = {};
+	int err = 0;
+	__u32 id, i;
+
+	r.dist_base_btf = btf__base_btf(btf);
+	if (!base_btf || r.dist_base_btf == base_btf)
+		return -EINVAL;
+
+	r.nr_dist_base_types = btf__type_cnt(r.dist_base_btf);
+	r.nr_base_types = btf__type_cnt(base_btf);
+	r.nr_split_types = nr_types - r.nr_dist_base_types;
+	r.btf = btf;
+	r.base_btf = base_btf;
+
+	r.id_map = calloc(nr_types, sizeof(*r.id_map));
+	r.str_map = calloc(btf_header(r.dist_base_btf)->str_len, sizeof(*r.str_map));
+	dist_base_hdr = btf_header(r.dist_base_btf);
+	base_hdr = btf_header(r.base_btf);
+	r.dist_str_len = dist_base_hdr->str_len;
+	r.base_str_len = base_hdr->str_len;
+	if (!r.id_map || !r.str_map) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	err = btf_relocate_validate_distilled_base(&r);
+	if (err)
+		goto err_out;
+
+	/* Split BTF ids need to be adjusted as base and distilled base
+	 * have different numbers of types, changing the start id of split
+	 * BTF.
+	 */
+	for (id = r.nr_dist_base_types; id < nr_types; id++)
+		r.id_map[id] = id + r.nr_base_types - r.nr_dist_base_types;
+
+	/* Build a map from distilled base ids to actual base BTF ids; it is used
+	 * to update split BTF id references.  Also build a str_map mapping from
+	 * distilled base BTF names to base BTF names.
+	 */
+	err = btf_relocate_map_distilled_base(&r);
+	if (err)
+		goto err_out;
+
+	/* Next, rewrite type ids in split BTF, replacing split ids with updated
+	 * ids based on number of types in base BTF, and base ids with
+	 * relocated ids from base_btf.
+	 */
+	for (i = 0, id = r.nr_dist_base_types; i < r.nr_split_types; i++, id++) {
+		err = btf_relocate_rewrite_type_id(&r, id);
+		if (err)
+			goto err_out;
+	}
+	/* String offsets now need to be updated using the str_map. */
+	for (i = 0; i < r.nr_split_types; i++) {
+		err = btf_relocate_rewrite_strs(&r, i + r.nr_dist_base_types);
+		if (err)
+			goto err_out;
+	}
+	/* Finally reset base BTF to be base_btf */
+	btf_set_base_btf(btf, base_btf);
+
+	if (id_map) {
+		*id_map = r.id_map;
+		r.id_map = NULL;
+	}
+err_out:
+	free(r.id_map);
+	free(r.str_map);
+	return err;
+}
diff --git a/tools/lib/bpf/elf.c b/tools/lib/bpf/elf.c
new file mode 100644
index 000000000..fe136d025
--- /dev/null
+++ b/tools/lib/bpf/elf.c
@@ -0,0 +1,558 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <libelf.h>
+#include <gelf.h>
+#include <fcntl.h>
+#include <linux/kernel.h>
+
+#include "libbpf_internal.h"
+
+/* A SHT_GNU_versym section holds 16-bit words. This bit is set if
+ * the symbol is hidden and can only be seen when referenced using an
+ * explicit version number. This is a GNU extension.
+ */
+#define VERSYM_HIDDEN	0x8000
+
+/* This is the mask for the rest of the data in a word read from a
+ * SHT_GNU_versym section.
+ */
+#define VERSYM_VERSION	0x7fff
+
+int elf_open(const char *binary_path, struct elf_fd *elf_fd)
+{
+	int fd, ret;
+	Elf *elf;
+
+	elf_fd->elf = NULL;
+	elf_fd->fd = -1;
+
+	if (elf_version(EV_CURRENT) == EV_NONE) {
+		pr_warn("elf: failed to init libelf for %s\n", binary_path);
+		return -LIBBPF_ERRNO__LIBELF;
+	}
+	fd = open(binary_path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		ret = -errno;
+		pr_warn("elf: failed to open %s: %s\n", binary_path, errstr(ret));
+		return ret;
+	}
+	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	if (!elf) {
+		pr_warn("elf: could not read elf from %s: %s\n", binary_path, elf_errmsg(-1));
+		close(fd);
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+	elf_fd->fd = fd;
+	elf_fd->elf = elf;
+	return 0;
+}
+
+void elf_close(struct elf_fd *elf_fd)
+{
+	if (!elf_fd)
+		return;
+	elf_end(elf_fd->elf);
+	close(elf_fd->fd);
+}
+
+/* Return next ELF section of sh_type after scn, or first of that type if scn is NULL. */
+static Elf_Scn *elf_find_next_scn_by_type(Elf *elf, int sh_type, Elf_Scn *scn)
+{
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		GElf_Shdr sh;
+
+		if (!gelf_getshdr(scn, &sh))
+			continue;
+		if (sh.sh_type == sh_type)
+			return scn;
+	}
+	return NULL;
+}
+
+struct elf_sym {
+	const char *name;
+	GElf_Sym sym;
+	GElf_Shdr sh;
+	int ver;
+	bool hidden;
+};
+
+struct elf_sym_iter {
+	Elf *elf;
+	Elf_Data *syms;
+	Elf_Data *versyms;
+	Elf_Data *verdefs;
+	size_t nr_syms;
+	size_t strtabidx;
+	size_t verdef_strtabidx;
+	size_t next_sym_idx;
+	struct elf_sym sym;
+	int st_type;
+};
+
+static int elf_sym_iter_new(struct elf_sym_iter *iter,
+			    Elf *elf, const char *binary_path,
+			    int sh_type, int st_type)
+{
+	Elf_Scn *scn = NULL;
+	GElf_Ehdr ehdr;
+	GElf_Shdr sh;
+
+	memset(iter, 0, sizeof(*iter));
+
+	if (!gelf_getehdr(elf, &ehdr)) {
+		pr_warn("elf: failed to get ehdr from %s: %s\n", binary_path, elf_errmsg(-1));
+		return -EINVAL;
+	}
+
+	scn = elf_find_next_scn_by_type(elf, sh_type, NULL);
+	if (!scn) {
+		pr_debug("elf: failed to find symbol table ELF sections in '%s'\n",
+			 binary_path);
+		return -ENOENT;
+	}
+
+	if (!gelf_getshdr(scn, &sh))
+		return -EINVAL;
+
+	iter->strtabidx = sh.sh_link;
+	iter->syms = elf_getdata(scn, 0);
+	if (!iter->syms) {
+		pr_warn("elf: failed to get symbols for symtab section in '%s': %s\n",
+			binary_path, elf_errmsg(-1));
+		return -EINVAL;
+	}
+	iter->nr_syms = iter->syms->d_size / sh.sh_entsize;
+	iter->elf = elf;
+	iter->st_type = st_type;
+
+	/* Version symbol table is meaningful to dynsym only */
+	if (sh_type != SHT_DYNSYM)
+		return 0;
+
+	scn = elf_find_next_scn_by_type(elf, SHT_GNU_versym, NULL);
+	if (!scn)
+		return 0;
+	iter->versyms = elf_getdata(scn, 0);
+
+	scn = elf_find_next_scn_by_type(elf, SHT_GNU_verdef, NULL);
+	if (!scn)
+		return 0;
+
+	iter->verdefs = elf_getdata(scn, 0);
+	if (!iter->verdefs || !gelf_getshdr(scn, &sh)) {
+		pr_warn("elf: failed to get verdef ELF section in '%s'\n", binary_path);
+		return -EINVAL;
+	}
+	iter->verdef_strtabidx = sh.sh_link;
+
+	return 0;
+}
+
+static struct elf_sym *elf_sym_iter_next(struct elf_sym_iter *iter)
+{
+	struct elf_sym *ret = &iter->sym;
+	GElf_Sym *sym = &ret->sym;
+	const char *name = NULL;
+	GElf_Versym versym;
+	Elf_Scn *sym_scn;
+	size_t idx;
+
+	for (idx = iter->next_sym_idx; idx < iter->nr_syms; idx++) {
+		if (!gelf_getsym(iter->syms, idx, sym))
+			continue;
+		if (GELF_ST_TYPE(sym->st_info) != iter->st_type)
+			continue;
+		name = elf_strptr(iter->elf, iter->strtabidx, sym->st_name);
+		if (!name)
+			continue;
+		sym_scn = elf_getscn(iter->elf, sym->st_shndx);
+		if (!sym_scn)
+			continue;
+		if (!gelf_getshdr(sym_scn, &ret->sh))
+			continue;
+
+		iter->next_sym_idx = idx + 1;
+		ret->name = name;
+		ret->ver = 0;
+		ret->hidden = false;
+
+		if (iter->versyms) {
+			if (!gelf_getversym(iter->versyms, idx, &versym))
+				continue;
+			ret->ver = versym & VERSYM_VERSION;
+			ret->hidden = versym & VERSYM_HIDDEN;
+		}
+		return ret;
+	}
+
+	return NULL;
+}
+
+static const char *elf_get_vername(struct elf_sym_iter *iter, int ver)
+{
+	GElf_Verdaux verdaux;
+	GElf_Verdef verdef;
+	int offset;
+
+	if (!iter->verdefs)
+		return NULL;
+
+	offset = 0;
+	while (gelf_getverdef(iter->verdefs, offset, &verdef)) {
+		if (verdef.vd_ndx != ver) {
+			if (!verdef.vd_next)
+				break;
+
+			offset += verdef.vd_next;
+			continue;
+		}
+
+		if (!gelf_getverdaux(iter->verdefs, offset + verdef.vd_aux, &verdaux))
+			break;
+
+		return elf_strptr(iter->elf, iter->verdef_strtabidx, verdaux.vda_name);
+
+	}
+	return NULL;
+}
+
+static bool symbol_match(struct elf_sym_iter *iter, int sh_type, struct elf_sym *sym,
+			 const char *name, size_t name_len, const char *lib_ver)
+{
+	const char *ver_name;
+
+	/* Symbols are in forms of func, func@LIB_VER or func@@LIB_VER
+	 * make sure the func part matches the user specified name
+	 */
+	if (strncmp(sym->name, name, name_len) != 0)
+		return false;
+
+	/* ...but we don't want a search for "foo" to match 'foo2" also, so any
+	 * additional characters in sname should be of the form "@@LIB".
+	 */
+	if (sym->name[name_len] != '\0' && sym->name[name_len] != '@')
+		return false;
+
+	/* If user does not specify symbol version, then we got a match */
+	if (!lib_ver)
+		return true;
+
+	/* If user specifies symbol version, for dynamic symbols,
+	 * get version name from ELF verdef section for comparison.
+	 */
+	if (sh_type == SHT_DYNSYM) {
+		ver_name = elf_get_vername(iter, sym->ver);
+		if (!ver_name)
+			return false;
+		return strcmp(ver_name, lib_ver) == 0;
+	}
+
+	/* For normal symbols, it is already in form of func@LIB_VER */
+	return strcmp(sym->name, name) == 0;
+}
+
+/* Transform symbol's virtual address (absolute for binaries and relative
+ * for shared libs) into file offset, which is what kernel is expecting
+ * for uprobe/uretprobe attachment.
+ * See Documentation/trace/uprobetracer.rst for more details. This is done
+ * by looking up symbol's containing section's header and using iter's virtual
+ * address (sh_addr) and corresponding file offset (sh_offset) to transform
+ * sym.st_value (virtual address) into desired final file offset.
+ */
+static unsigned long elf_sym_offset(struct elf_sym *sym)
+{
+	return sym->sym.st_value - sym->sh.sh_addr + sym->sh.sh_offset;
+}
+
+/* Find offset of function name in the provided ELF object. "binary_path" is
+ * the path to the ELF binary represented by "elf", and only used for error
+ * reporting matters. "name" matches symbol name or name@@LIB for library
+ * functions.
+ */
+long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name)
+{
+	int i, sh_types[2] = { SHT_DYNSYM, SHT_SYMTAB };
+	const char *at_symbol, *lib_ver;
+	bool is_shared_lib;
+	long ret = -ENOENT;
+	size_t name_len;
+	GElf_Ehdr ehdr;
+
+	if (!gelf_getehdr(elf, &ehdr)) {
+		pr_warn("elf: failed to get ehdr from %s: %s\n", binary_path, elf_errmsg(-1));
+		ret = -LIBBPF_ERRNO__FORMAT;
+		goto out;
+	}
+	/* for shared lib case, we do not need to calculate relative offset */
+	is_shared_lib = ehdr.e_type == ET_DYN;
+
+	/* Does name specify "@@LIB_VER" or "@LIB_VER" ? */
+	at_symbol = strchr(name, '@');
+	if (at_symbol) {
+		name_len = at_symbol - name;
+		/* skip second @ if it's @@LIB_VER case */
+		if (at_symbol[1] == '@')
+			at_symbol++;
+		lib_ver = at_symbol + 1;
+	} else {
+		name_len = strlen(name);
+		lib_ver = NULL;
+	}
+
+	/* Search SHT_DYNSYM, SHT_SYMTAB for symbol. This search order is used because if
+	 * a binary is stripped, it may only have SHT_DYNSYM, and a fully-statically
+	 * linked binary may not have SHT_DYMSYM, so absence of a section should not be
+	 * reported as a warning/error.
+	 */
+	for (i = 0; i < ARRAY_SIZE(sh_types); i++) {
+		struct elf_sym_iter iter;
+		struct elf_sym *sym;
+		int last_bind = -1;
+		int cur_bind;
+
+		ret = elf_sym_iter_new(&iter, elf, binary_path, sh_types[i], STT_FUNC);
+		if (ret == -ENOENT)
+			continue;
+		if (ret)
+			goto out;
+
+		while ((sym = elf_sym_iter_next(&iter))) {
+			if (!symbol_match(&iter, sh_types[i], sym, name, name_len, lib_ver))
+				continue;
+
+			cur_bind = GELF_ST_BIND(sym->sym.st_info);
+
+			if (ret > 0) {
+				/* handle multiple matches */
+				if (elf_sym_offset(sym) == ret) {
+					/* same offset, no problem */
+					continue;
+				} else if (last_bind != STB_WEAK && cur_bind != STB_WEAK) {
+					/* Only accept one non-weak bind. */
+					pr_warn("elf: ambiguous match for '%s', '%s' in '%s'\n",
+						sym->name, name, binary_path);
+					ret = -LIBBPF_ERRNO__FORMAT;
+					goto out;
+				} else if (cur_bind == STB_WEAK) {
+					/* already have a non-weak bind, and
+					 * this is a weak bind, so ignore.
+					 */
+					continue;
+				}
+			}
+
+			ret = elf_sym_offset(sym);
+			last_bind = cur_bind;
+		}
+		if (ret > 0)
+			break;
+	}
+
+	if (ret > 0) {
+		pr_debug("elf: symbol address match for '%s' in '%s': 0x%lx\n", name, binary_path,
+			 (unsigned long)ret);
+	} else {
+		if (ret == 0) {
+			pr_warn("elf: '%s' is 0 in symtab for '%s': %s\n", name, binary_path,
+				is_shared_lib ? "should not be 0 in a shared library" :
+						"try using shared library path instead");
+			ret = -ENOENT;
+		} else {
+			pr_warn("elf: failed to find symbol '%s' in '%s'\n", name, binary_path);
+		}
+	}
+out:
+	return ret;
+}
+
+/* Find offset of function name in ELF object specified by path. "name" matches
+ * symbol name or name@@LIB for library functions.
+ */
+long elf_find_func_offset_from_file(const char *binary_path, const char *name)
+{
+	struct elf_fd elf_fd;
+	long ret = -ENOENT;
+
+	ret = elf_open(binary_path, &elf_fd);
+	if (ret)
+		return ret;
+	ret = elf_find_func_offset(elf_fd.elf, binary_path, name);
+	elf_close(&elf_fd);
+	return ret;
+}
+
+struct symbol {
+	const char *name;
+	int bind;
+	int idx;
+};
+
+static int symbol_cmp(const void *a, const void *b)
+{
+	const struct symbol *sym_a = a;
+	const struct symbol *sym_b = b;
+
+	return strcmp(sym_a->name, sym_b->name);
+}
+
+/*
+ * Return offsets in @poffsets for symbols specified in @syms array argument.
+ * On success returns 0 and offsets are returned in allocated array with @cnt
+ * size, that needs to be released by the caller.
+ */
+int elf_resolve_syms_offsets(const char *binary_path, int cnt,
+			     const char **syms, unsigned long **poffsets,
+			     int st_type)
+{
+	int sh_types[2] = { SHT_DYNSYM, SHT_SYMTAB };
+	int err = 0, i, cnt_done = 0;
+	unsigned long *offsets;
+	struct symbol *symbols;
+	struct elf_fd elf_fd;
+
+	err = elf_open(binary_path, &elf_fd);
+	if (err)
+		return err;
+
+	offsets = calloc(cnt, sizeof(*offsets));
+	symbols = calloc(cnt, sizeof(*symbols));
+
+	if (!offsets || !symbols) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < cnt; i++) {
+		symbols[i].name = syms[i];
+		symbols[i].idx = i;
+	}
+
+	qsort(symbols, cnt, sizeof(*symbols), symbol_cmp);
+
+	for (i = 0; i < ARRAY_SIZE(sh_types); i++) {
+		struct elf_sym_iter iter;
+		struct elf_sym *sym;
+
+		err = elf_sym_iter_new(&iter, elf_fd.elf, binary_path, sh_types[i], st_type);
+		if (err == -ENOENT)
+			continue;
+		if (err)
+			goto out;
+
+		while ((sym = elf_sym_iter_next(&iter))) {
+			unsigned long sym_offset = elf_sym_offset(sym);
+			int bind = GELF_ST_BIND(sym->sym.st_info);
+			struct symbol *found, tmp = {
+				.name = sym->name,
+			};
+			unsigned long *offset;
+
+			found = bsearch(&tmp, symbols, cnt, sizeof(*symbols), symbol_cmp);
+			if (!found)
+				continue;
+
+			offset = &offsets[found->idx];
+			if (*offset > 0) {
+				/* same offset, no problem */
+				if (*offset == sym_offset)
+					continue;
+				/* handle multiple matches */
+				if (found->bind != STB_WEAK && bind != STB_WEAK) {
+					/* Only accept one non-weak bind. */
+					pr_warn("elf: ambiguous match found '%s@%lu' in '%s' previous offset %lu\n",
+						sym->name, sym_offset, binary_path, *offset);
+					err = -ESRCH;
+					goto out;
+				} else if (bind == STB_WEAK) {
+					/* already have a non-weak bind, and
+					 * this is a weak bind, so ignore.
+					 */
+					continue;
+				}
+			} else {
+				cnt_done++;
+			}
+			*offset = sym_offset;
+			found->bind = bind;
+		}
+	}
+
+	if (cnt != cnt_done) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	*poffsets = offsets;
+
+out:
+	free(symbols);
+	if (err)
+		free(offsets);
+	elf_close(&elf_fd);
+	return err;
+}
+
+/*
+ * Return offsets in @poffsets for symbols specified by @pattern argument.
+ * On success returns 0 and offsets are returned in allocated @poffsets
+ * array with the @pctn size, that needs to be released by the caller.
+ */
+int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
+				unsigned long **poffsets, size_t *pcnt)
+{
+	int sh_types[2] = { SHT_SYMTAB, SHT_DYNSYM };
+	unsigned long *offsets = NULL;
+	size_t cap = 0, cnt = 0;
+	struct elf_fd elf_fd;
+	int err = 0, i;
+
+	err = elf_open(binary_path, &elf_fd);
+	if (err)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(sh_types); i++) {
+		struct elf_sym_iter iter;
+		struct elf_sym *sym;
+
+		err = elf_sym_iter_new(&iter, elf_fd.elf, binary_path, sh_types[i], STT_FUNC);
+		if (err == -ENOENT)
+			continue;
+		if (err)
+			goto out;
+
+		while ((sym = elf_sym_iter_next(&iter))) {
+			if (!glob_match(sym->name, pattern))
+				continue;
+
+			err = libbpf_ensure_mem((void **) &offsets, &cap, sizeof(*offsets),
+						cnt + 1);
+			if (err)
+				goto out;
+
+			offsets[cnt++] = elf_sym_offset(sym);
+		}
+
+		/* If we found anything in the first symbol section,
+		 * do not search others to avoid duplicates.
+		 */
+		if (cnt)
+			break;
+	}
+
+	if (cnt) {
+		*poffsets = offsets;
+		*pcnt = cnt;
+	} else {
+		err = -ENOENT;
+	}
+
+out:
+	if (err)
+		free(offsets);
+	elf_close(&elf_fd);
+	return err;
+}
diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c
new file mode 100644
index 000000000..9f589980b
--- /dev/null
+++ b/tools/lib/bpf/features.c
@@ -0,0 +1,770 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+#include <linux/kernel.h>
+#include <linux/filter.h>
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_common.h"
+#include "libbpf_internal.h"
+
+static inline __u64 ptr_to_u64(const void *ptr)
+{
+	return (__u64)(unsigned long)ptr;
+}
+
+int probe_fd(int fd)
+{
+	if (fd >= 0)
+		close(fd);
+	return fd >= 0;
+}
+
+static int probe_kern_prog_name(int token_fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, prog_token_fd);
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	union bpf_attr attr;
+	int ret;
+
+	memset(&attr, 0, attr_sz);
+	attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
+	attr.license = ptr_to_u64("GPL");
+	attr.insns = ptr_to_u64(insns);
+	attr.insn_cnt = (__u32)ARRAY_SIZE(insns);
+	attr.prog_token_fd = token_fd;
+	if (token_fd)
+		attr.prog_flags |= BPF_F_TOKEN_FD;
+	libbpf_strlcpy(attr.prog_name, "libbpf_nametest", sizeof(attr.prog_name));
+
+	/* make sure loading with name works */
+	ret = sys_bpf_prog_load(&attr, attr_sz, PROG_LOAD_ATTEMPTS);
+	return probe_fd(ret);
+}
+
+static int probe_kern_global_data(int token_fd)
+{
+	struct bpf_insn insns[] = {
+		BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
+		BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	LIBBPF_OPTS(bpf_map_create_opts, map_opts,
+		.token_fd = token_fd,
+		.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int ret, map, insn_cnt = ARRAY_SIZE(insns);
+
+	map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_global", sizeof(int), 32, 1, &map_opts);
+	if (map < 0) {
+		ret = -errno;
+		pr_warn("Error in %s(): %s. Couldn't create simple array map.\n",
+			__func__, errstr(ret));
+		return ret;
+	}
+
+	insns[0].imm = map;
+
+	ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, &prog_opts);
+	close(map);
+	return probe_fd(ret);
+}
+
+static int probe_kern_btf(int token_fd)
+{
+	static const char strs[] = "\0int";
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_func(int token_fd)
+{
+	static const char strs[] = "\0int\0x\0a";
+	/* void x(int a) {} */
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* FUNC_PROTO */                                /* [2] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
+		BTF_PARAM_ENC(7, 1),
+		/* FUNC x */                                    /* [3] */
+		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_func_global(int token_fd)
+{
+	static const char strs[] = "\0int\0x\0a";
+	/* static void x(int a) {} */
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* FUNC_PROTO */                                /* [2] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
+		BTF_PARAM_ENC(7, 1),
+		/* FUNC x BTF_FUNC_GLOBAL */                    /* [3] */
+		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_datasec(int token_fd)
+{
+	static const char strs[] = "\0x\0.data";
+	/* static int a; */
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* VAR x */                                     /* [2] */
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
+		BTF_VAR_STATIC,
+		/* DATASEC val */                               /* [3] */
+		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
+		BTF_VAR_SECINFO_ENC(2, 0, 4),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_qmark_datasec(int token_fd)
+{
+	static const char strs[] = "\0x\0?.data";
+	/* static int a; */
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* VAR x */                                     /* [2] */
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
+		BTF_VAR_STATIC,
+		/* DATASEC ?.data */                            /* [3] */
+		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
+		BTF_VAR_SECINFO_ENC(2, 0, 4),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_float(int token_fd)
+{
+	static const char strs[] = "\0float";
+	__u32 types[] = {
+		/* float */
+		BTF_TYPE_FLOAT_ENC(1, 4),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_decl_tag(int token_fd)
+{
+	static const char strs[] = "\0tag";
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* VAR x */                                     /* [2] */
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
+		BTF_VAR_STATIC,
+		/* attr */
+		BTF_TYPE_DECL_TAG_ENC(1, 2, -1),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_btf_type_tag(int token_fd)
+{
+	static const char strs[] = "\0tag";
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		/* attr */
+		BTF_TYPE_TYPE_TAG_ENC(1, 1),				/* [2] */
+		/* ptr */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2),	/* [3] */
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_array_mmap(int token_fd)
+{
+	LIBBPF_OPTS(bpf_map_create_opts, opts,
+		.map_flags = BPF_F_MMAPABLE | (token_fd ? BPF_F_TOKEN_FD : 0),
+		.token_fd = token_fd,
+	);
+	int fd;
+
+	fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_mmap", sizeof(int), sizeof(int), 1, &opts);
+	return probe_fd(fd);
+}
+
+static int probe_kern_exp_attach_type(int token_fd)
+{
+	LIBBPF_OPTS(bpf_prog_load_opts, opts,
+		.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	int fd, insn_cnt = ARRAY_SIZE(insns);
+
+	/* use any valid combination of program type and (optional)
+	 * non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS)
+	 * to see if kernel supports expected_attach_type field for
+	 * BPF_PROG_LOAD command
+	 */
+	fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns, insn_cnt, &opts);
+	return probe_fd(fd);
+}
+
+static int probe_kern_probe_read_kernel(int token_fd)
+{
+	LIBBPF_OPTS(bpf_prog_load_opts, opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	struct bpf_insn insns[] = {
+		BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),	/* r1 = r10 (fp) */
+		BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),	/* r1 += -8 */
+		BPF_MOV64_IMM(BPF_REG_2, 8),		/* r2 = 8 */
+		BPF_MOV64_IMM(BPF_REG_3, 0),		/* r3 = 0 */
+		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
+		BPF_EXIT_INSN(),
+	};
+	int fd, insn_cnt = ARRAY_SIZE(insns);
+
+	fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, &opts);
+	return probe_fd(fd);
+}
+
+static int probe_prog_bind_map(int token_fd)
+{
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	LIBBPF_OPTS(bpf_map_create_opts, map_opts,
+		.token_fd = token_fd,
+		.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int ret, map, prog, insn_cnt = ARRAY_SIZE(insns);
+
+	map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_det_bind", sizeof(int), 32, 1, &map_opts);
+	if (map < 0) {
+		ret = -errno;
+		pr_warn("Error in %s(): %s. Couldn't create simple array map.\n",
+			__func__, errstr(ret));
+		return ret;
+	}
+
+	prog = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, &prog_opts);
+	if (prog < 0) {
+		close(map);
+		return 0;
+	}
+
+	ret = bpf_prog_bind_map(prog, map, NULL);
+
+	close(map);
+	close(prog);
+
+	return ret >= 0;
+}
+
+static int probe_module_btf(int token_fd)
+{
+	static const char strs[] = "\0int";
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
+	};
+	struct bpf_btf_info info;
+	__u32 len = sizeof(info);
+	char name[16];
+	int fd, err;
+
+	fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs), token_fd);
+	if (fd < 0)
+		return 0; /* BTF not supported at all */
+
+	memset(&info, 0, sizeof(info));
+	info.name = ptr_to_u64(name);
+	info.name_len = sizeof(name);
+
+	/* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer;
+	 * kernel's module BTF support coincides with support for
+	 * name/name_len fields in struct bpf_btf_info.
+	 */
+	err = bpf_btf_get_info_by_fd(fd, &info, &len);
+	close(fd);
+	return !err;
+}
+
+static int probe_perf_link(int token_fd)
+{
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	LIBBPF_OPTS(bpf_prog_load_opts, opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int prog_fd, link_fd, err;
+
+	prog_fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL",
+				insns, ARRAY_SIZE(insns), &opts);
+	if (prog_fd < 0)
+		return -errno;
+
+	/* use invalid perf_event FD to get EBADF, if link is supported;
+	 * otherwise EINVAL should be returned
+	 */
+	link_fd = bpf_link_create(prog_fd, -1, BPF_PERF_EVENT, NULL);
+	err = -errno; /* close() can clobber errno */
+
+	if (link_fd >= 0)
+		close(link_fd);
+	close(prog_fd);
+
+	return link_fd < 0 && err == -EBADF;
+}
+
+static int probe_uprobe_multi_link(int token_fd)
+{
+	LIBBPF_OPTS(bpf_prog_load_opts, load_opts,
+		.expected_attach_type = BPF_TRACE_UPROBE_MULTI,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	LIBBPF_OPTS(bpf_link_create_opts, link_opts);
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	int prog_fd, link_fd, err;
+	unsigned long offset = 0;
+
+	prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL",
+				insns, ARRAY_SIZE(insns), &load_opts);
+	if (prog_fd < 0)
+		return -errno;
+
+	/* Creating uprobe in '/' binary should fail with -EBADF. */
+	link_opts.uprobe_multi.path = "/";
+	link_opts.uprobe_multi.offsets = &offset;
+	link_opts.uprobe_multi.cnt = 1;
+
+	link_fd = bpf_link_create(prog_fd, -1, BPF_TRACE_UPROBE_MULTI, &link_opts);
+	err = -errno; /* close() can clobber errno */
+
+	if (link_fd >= 0 || err != -EBADF) {
+		if (link_fd >= 0)
+			close(link_fd);
+		close(prog_fd);
+		return 0;
+	}
+
+	/* Initial multi-uprobe support in kernel didn't handle PID filtering
+	 * correctly (it was doing thread filtering, not process filtering).
+	 * So now we'll detect if PID filtering logic was fixed, and, if not,
+	 * we'll pretend multi-uprobes are not supported, if not.
+	 * Multi-uprobes are used in USDT attachment logic, and we need to be
+	 * conservative here, because multi-uprobe selection happens early at
+	 * load time, while the use of PID filtering is known late at
+	 * attachment time, at which point it's too late to undo multi-uprobe
+	 * selection.
+	 *
+	 * Creating uprobe with pid == -1 for (invalid) '/' binary will fail
+	 * early with -EINVAL on kernels with fixed PID filtering logic;
+	 * otherwise -ESRCH would be returned if passed correct binary path
+	 * (but we'll just get -BADF, of course).
+	 */
+	link_opts.uprobe_multi.pid = -1; /* invalid PID */
+	link_opts.uprobe_multi.path = "/"; /* invalid path */
+	link_opts.uprobe_multi.offsets = &offset;
+	link_opts.uprobe_multi.cnt = 1;
+
+	link_fd = bpf_link_create(prog_fd, -1, BPF_TRACE_UPROBE_MULTI, &link_opts);
+	err = -errno; /* close() can clobber errno */
+
+	if (link_fd >= 0)
+		close(link_fd);
+	close(prog_fd);
+
+	return link_fd < 0 && err == -EINVAL;
+}
+
+static int probe_kern_bpf_cookie(int token_fd)
+{
+	struct bpf_insn insns[] = {
+		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_attach_cookie),
+		BPF_EXIT_INSN(),
+	};
+	LIBBPF_OPTS(bpf_prog_load_opts, opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int ret, insn_cnt = ARRAY_SIZE(insns);
+
+	ret = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, &opts);
+	return probe_fd(ret);
+}
+
+static int probe_kern_btf_enum64(int token_fd)
+{
+	static const char strs[] = "\0enum64";
+	__u32 types[] = {
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_ENUM64, 0, 0), 8),
+	};
+
+	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
+					     strs, sizeof(strs), token_fd));
+}
+
+static int probe_kern_arg_ctx_tag(int token_fd)
+{
+	static const char strs[] = "\0a\0b\0arg:ctx\0";
+	const __u32 types[] = {
+		/* [1] INT */
+		BTF_TYPE_INT_ENC(1 /* "a" */, BTF_INT_SIGNED, 0, 32, 4),
+		/* [2] PTR -> VOID */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 0),
+		/* [3] FUNC_PROTO `int(void *a)` */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1),
+		BTF_PARAM_ENC(1 /* "a" */, 2),
+		/* [4] FUNC 'a' -> FUNC_PROTO (main prog) */
+		BTF_TYPE_ENC(1 /* "a" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 3),
+		/* [5] FUNC_PROTO `int(void *b __arg_ctx)` */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 1),
+		BTF_PARAM_ENC(3 /* "b" */, 2),
+		/* [6] FUNC 'b' -> FUNC_PROTO (subprog) */
+		BTF_TYPE_ENC(3 /* "b" */, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 5),
+		/* [7] DECL_TAG 'arg:ctx' -> func 'b' arg 'b' */
+		BTF_TYPE_DECL_TAG_ENC(5 /* "arg:ctx" */, 6, 0),
+	};
+	const struct bpf_insn insns[] = {
+		/* main prog */
+		BPF_CALL_REL(+1),
+		BPF_EXIT_INSN(),
+		/* global subprog */
+		BPF_EMIT_CALL(BPF_FUNC_get_func_ip), /* needs PTR_TO_CTX */
+		BPF_EXIT_INSN(),
+	};
+	const struct bpf_func_info_min func_infos[] = {
+		{ 0, 4 }, /* main prog -> FUNC 'a' */
+		{ 2, 6 }, /* subprog -> FUNC 'b' */
+	};
+	LIBBPF_OPTS(bpf_prog_load_opts, opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int prog_fd, btf_fd, insn_cnt = ARRAY_SIZE(insns);
+
+	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs), token_fd);
+	if (btf_fd < 0)
+		return 0;
+
+	opts.prog_btf_fd = btf_fd;
+	opts.func_info = &func_infos;
+	opts.func_info_cnt = ARRAY_SIZE(func_infos);
+	opts.func_info_rec_size = sizeof(func_infos[0]);
+
+	prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, "det_arg_ctx",
+				"GPL", insns, insn_cnt, &opts);
+	close(btf_fd);
+
+	return probe_fd(prog_fd);
+}
+
+static int probe_ldimm64_full_range_off(int token_fd)
+{
+	char log_buf[1024];
+	int prog_fd, map_fd;
+	int ret;
+	LIBBPF_OPTS(bpf_map_create_opts, map_opts,
+		.token_fd = token_fd,
+		.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+		.log_buf = log_buf,
+		.log_size = sizeof(log_buf),
+	);
+	struct bpf_insn insns[] = {
+		BPF_LD_MAP_VALUE(BPF_REG_1, 0, 1UL << 30),
+		BPF_EXIT_INSN(),
+	};
+	int insn_cnt = ARRAY_SIZE(insns);
+
+	map_fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "arr", sizeof(int), 1, 1, &map_opts);
+	if (map_fd < 0) {
+		ret = -errno;
+		pr_warn("Error in %s(): %s. Couldn't create simple array map.\n",
+			__func__, errstr(ret));
+		return ret;
+	}
+	insns[0].imm = map_fd;
+
+	log_buf[0] = '\0';
+	prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "global_reloc", "GPL", insns, insn_cnt, &prog_opts);
+	ret = -errno;
+
+	close(map_fd);
+
+	if (prog_fd >= 0) {
+		pr_warn("Error in %s(): Program loading unexpectedly succeeded.\n", __func__);
+		close(prog_fd);
+		return -EINVAL;
+	}
+
+	/*
+	 * Feature is allowed if we're not failing with the error message
+	 * "direct value offset of %u is not allowed" removed in
+	 * 12a1fe6e12db ("bpf/verifier: Do not limit maximum direct offset into arena map").
+	 * We should instead fail with "invalid access to map value pointer".
+	 * Ensure we match with one of the two and we're not failing with a
+	 * different, unexpected message.
+	 */
+	if (strstr(log_buf, "direct value offset of"))
+		return 0;
+
+	if (!strstr(log_buf, "invalid access to map value pointer")) {
+		pr_warn("Error in %s(): Program unexpectedly failed with message: %s.\n",
+			__func__, log_buf);
+		return ret;
+	}
+
+	return 1;
+}
+
+#ifdef __x86_64__
+
+#ifndef __NR_uprobe
+#define __NR_uprobe 336
+#endif
+
+static int probe_uprobe_syscall(int token_fd)
+{
+	/*
+	 * If kernel supports uprobe() syscall, it will return -EPROTO when called
+	 * from the outside of a kernel-generated uprobe trampoline.
+	 */
+	return syscall(__NR_uprobe) < 0 && errno == EPROTO;
+}
+#else
+static int probe_uprobe_syscall(int token_fd)
+{
+	return 0;
+}
+#endif
+
+static int probe_kern_btf_layout(int token_fd)
+{
+	static const char strs[] = "\0int";
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
+	};
+	struct btf_layout layout[] = {
+		{ 0,			0,	0 },
+		{ sizeof(__u32),	0,	0 },
+	};
+	struct btf_header hdr = {
+		.magic = BTF_MAGIC,
+		.version = BTF_VERSION,
+		.hdr_len = sizeof(struct btf_header),
+		.type_len = sizeof(types),
+		.str_off = sizeof(types) + sizeof(layout),
+		.str_len = sizeof(strs),
+		.layout_off = sizeof(types),
+		.layout_len = sizeof(layout),
+	};
+
+	return probe_fd(libbpf__load_raw_btf_hdr(&hdr, (char *)types, strs,
+						 (char *)layout, token_fd));
+}
+
+static int probe_bpf_syscall_common_attrs(int token_fd)
+{
+	return probe_sys_bpf_ext();
+}
+
+static int probe_kern_percpu_data(int token_fd)
+{
+	struct bpf_insn insns[] = {
+		BPF_LD_MAP_VALUE(BPF_REG_1, 0, 0),
+		BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
+		BPF_EXIT_INSN(),
+	};
+	LIBBPF_OPTS(bpf_map_create_opts, map_opts,
+		.token_fd = token_fd,
+		.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int ret, map, insn_cnt = ARRAY_SIZE(insns);
+
+	map = bpf_map_create(BPF_MAP_TYPE_PERCPU_ARRAY, "libbpf_percpu", sizeof(int), 8, 1,
+			     &map_opts);
+	if (map < 0) {
+		pr_warn("Error in %s(): %s. Couldn't create simple percpu_array map.\n",
+			__func__, errstr(map));
+		return map;
+	}
+
+	insns[0].imm = map;
+
+	ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, &prog_opts);
+	close(map);
+	return probe_fd(ret);
+}
+
+typedef int (*feature_probe_fn)(int /* token_fd */);
+
+static struct kern_feature_cache feature_cache;
+
+static struct kern_feature_desc {
+	const char *desc;
+	feature_probe_fn probe;
+} feature_probes[__FEAT_CNT] = {
+	[FEAT_PROG_NAME] = {
+		"BPF program name", probe_kern_prog_name,
+	},
+	[FEAT_GLOBAL_DATA] = {
+		"global variables", probe_kern_global_data,
+	},
+	[FEAT_BTF] = {
+		"minimal BTF", probe_kern_btf,
+	},
+	[FEAT_BTF_FUNC] = {
+		"BTF functions", probe_kern_btf_func,
+	},
+	[FEAT_BTF_GLOBAL_FUNC] = {
+		"BTF global function", probe_kern_btf_func_global,
+	},
+	[FEAT_BTF_DATASEC] = {
+		"BTF data section and variable", probe_kern_btf_datasec,
+	},
+	[FEAT_ARRAY_MMAP] = {
+		"ARRAY map mmap()", probe_kern_array_mmap,
+	},
+	[FEAT_EXP_ATTACH_TYPE] = {
+		"BPF_PROG_LOAD expected_attach_type attribute",
+		probe_kern_exp_attach_type,
+	},
+	[FEAT_PROBE_READ_KERN] = {
+		"bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel,
+	},
+	[FEAT_PROG_BIND_MAP] = {
+		"BPF_PROG_BIND_MAP support", probe_prog_bind_map,
+	},
+	[FEAT_MODULE_BTF] = {
+		"module BTF support", probe_module_btf,
+	},
+	[FEAT_BTF_FLOAT] = {
+		"BTF_KIND_FLOAT support", probe_kern_btf_float,
+	},
+	[FEAT_PERF_LINK] = {
+		"BPF perf link support", probe_perf_link,
+	},
+	[FEAT_BTF_DECL_TAG] = {
+		"BTF_KIND_DECL_TAG support", probe_kern_btf_decl_tag,
+	},
+	[FEAT_BTF_TYPE_TAG] = {
+		"BTF_KIND_TYPE_TAG support", probe_kern_btf_type_tag,
+	},
+	[FEAT_MEMCG_ACCOUNT] = {
+		"memcg-based memory accounting", probe_memcg_account,
+	},
+	[FEAT_BPF_COOKIE] = {
+		"BPF cookie support", probe_kern_bpf_cookie,
+	},
+	[FEAT_BTF_ENUM64] = {
+		"BTF_KIND_ENUM64 support", probe_kern_btf_enum64,
+	},
+	[FEAT_SYSCALL_WRAPPER] = {
+		"Kernel using syscall wrapper", probe_kern_syscall_wrapper,
+	},
+	[FEAT_UPROBE_MULTI_LINK] = {
+		"BPF multi-uprobe link support", probe_uprobe_multi_link,
+	},
+	[FEAT_ARG_CTX_TAG] = {
+		"kernel-side __arg_ctx tag", probe_kern_arg_ctx_tag,
+	},
+	[FEAT_BTF_QMARK_DATASEC] = {
+		"BTF DATASEC names starting from '?'", probe_kern_btf_qmark_datasec,
+	},
+	[FEAT_LDIMM64_FULL_RANGE_OFF] = {
+		"full range LDIMM64 support", probe_ldimm64_full_range_off,
+	},
+	[FEAT_UPROBE_SYSCALL] = {
+		"kernel supports uprobe syscall", probe_uprobe_syscall,
+	},
+	[FEAT_BTF_LAYOUT] = {
+		"kernel supports BTF layout", probe_kern_btf_layout,
+	},
+	[FEAT_BPF_SYSCALL_COMMON_ATTRS] = {
+		"BPF syscall common attributes support", probe_bpf_syscall_common_attrs,
+	},
+	[FEAT_PERCPU_DATA] = {
+		"kernel supports percpu data", probe_kern_percpu_data,
+	},
+};
+
+bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id)
+{
+	struct kern_feature_desc *feat = &feature_probes[feat_id];
+	int ret;
+
+	/* assume global feature cache, unless custom one is provided */
+	if (!cache)
+		cache = &feature_cache;
+
+	if (READ_ONCE(cache->res[feat_id]) == FEAT_UNKNOWN) {
+		ret = feat->probe(cache->token_fd);
+		if (ret > 0) {
+			WRITE_ONCE(cache->res[feat_id], FEAT_SUPPORTED);
+		} else if (ret == 0) {
+			WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
+		} else {
+			pr_warn("Detection of kernel %s support failed: %s\n",
+				feat->desc, errstr(ret));
+			WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
+		}
+	}
+
+	return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED;
+}
diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c
new file mode 100644
index 000000000..af3a04f16
--- /dev/null
+++ b/tools/lib/bpf/gen_loader.c
@@ -0,0 +1,1233 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2021 Facebook */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <asm/byteorder.h>
+#include <linux/filter.h>
+#include <sys/param.h>
+#include "btf.h"
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+#include "hashmap.h"
+#include "bpf_gen_internal.h"
+#include "skel_internal.h"
+
+#define MAX_USED_MAPS	64
+#define MAX_USED_PROGS	32
+#define MAX_KFUNC_DESCS 256
+#define MAX_FD_ARRAY_SZ (MAX_USED_MAPS + MAX_KFUNC_DESCS)
+
+/* The following structure describes the stack layout of the loader program.
+ * In addition R6 contains the pointer to context.
+ * R7 contains the result of the last sys_bpf command (typically error or FD).
+ * R9 contains the result of the last sys_close command.
+ *
+ * Naming convention:
+ * ctx - bpf program context
+ * stack - bpf program stack
+ * blob - bpf_attr-s, strings, insns, map data.
+ *        All the bytes that loader prog will use for read/write.
+ */
+struct loader_stack {
+	__u32 btf_fd;
+	__u32 inner_map_fd;
+	__u32 prog_fd[MAX_USED_PROGS];
+};
+
+#define stack_off(field) \
+	(__s16)(-sizeof(struct loader_stack) + offsetof(struct loader_stack, field))
+
+#define attr_field(attr, field) (attr + offsetof(union bpf_attr, field))
+
+static int blob_fd_array_off(struct bpf_gen *gen, int index)
+{
+	return gen->fd_array + index * sizeof(int);
+}
+
+static int realloc_insn_buf(struct bpf_gen *gen, __u32 size)
+{
+	size_t off = gen->insn_cur - gen->insn_start;
+	void *insn_start;
+
+	if (gen->error)
+		return gen->error;
+	if (size > INT32_MAX || off + size > INT32_MAX) {
+		gen->error = -ERANGE;
+		return -ERANGE;
+	}
+	insn_start = realloc(gen->insn_start, off + size);
+	if (!insn_start) {
+		gen->error = -ENOMEM;
+		free(gen->insn_start);
+		gen->insn_start = NULL;
+		gen->insn_cur = NULL;
+		return -ENOMEM;
+	}
+	gen->insn_start = insn_start;
+	gen->insn_cur = insn_start + off;
+	return 0;
+}
+
+static int realloc_data_buf(struct bpf_gen *gen, __u32 size)
+{
+	size_t off = gen->data_cur - gen->data_start;
+	void *data_start;
+
+	if (gen->error)
+		return gen->error;
+	if (size > INT32_MAX || off + size > INT32_MAX) {
+		gen->error = -ERANGE;
+		return -ERANGE;
+	}
+	data_start = realloc(gen->data_start, off + size);
+	if (!data_start) {
+		gen->error = -ENOMEM;
+		free(gen->data_start);
+		gen->data_start = NULL;
+		gen->data_cur = NULL;
+		return -ENOMEM;
+	}
+	gen->data_start = data_start;
+	gen->data_cur = data_start + off;
+	return 0;
+}
+
+static void emit(struct bpf_gen *gen, struct bpf_insn insn)
+{
+	if (realloc_insn_buf(gen, sizeof(insn)))
+		return;
+	memcpy(gen->insn_cur, &insn, sizeof(insn));
+	gen->insn_cur += sizeof(insn);
+}
+
+static void emit2(struct bpf_gen *gen, struct bpf_insn insn1, struct bpf_insn insn2)
+{
+	emit(gen, insn1);
+	emit(gen, insn2);
+}
+
+static int add_data(struct bpf_gen *gen, const void *data, __u32 size);
+static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off);
+
+void bpf_gen__init(struct bpf_gen *gen, int log_level, int nr_progs, int nr_maps)
+{
+	size_t stack_sz = sizeof(struct loader_stack), nr_progs_sz;
+	int i;
+
+	gen->fd_array = add_data(gen, NULL, MAX_FD_ARRAY_SZ * sizeof(int));
+	gen->log_level = log_level;
+	/* save ctx pointer into R6 */
+	emit(gen, BPF_MOV64_REG(BPF_REG_6, BPF_REG_1));
+
+	/* bzero stack */
+	emit(gen, BPF_MOV64_REG(BPF_REG_1, BPF_REG_10));
+	emit(gen, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -stack_sz));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, stack_sz));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
+
+	/* amount of stack actually used, only used to calculate iterations, not stack offset */
+	nr_progs_sz = offsetof(struct loader_stack, prog_fd[nr_progs]);
+	/* jump over cleanup code */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0,
+			      /* size of cleanup code below (including map fd cleanup) */
+			      (nr_progs_sz / 4) * 3 + 2 +
+			      /* 6 insns for emit_sys_close_blob,
+			       * 6 insns for debug_regs in emit_sys_close_blob
+			       */
+			      nr_maps * (6 + (gen->log_level ? 6 : 0))));
+
+	/* remember the label where all error branches will jump to */
+	gen->cleanup_label = gen->insn_cur - gen->insn_start;
+	/* emit cleanup code: close all temp FDs */
+	for (i = 0; i < nr_progs_sz; i += 4) {
+		emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -stack_sz + i));
+		emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0, 1));
+		emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close));
+	}
+	for (i = 0; i < nr_maps; i++)
+		emit_sys_close_blob(gen, blob_fd_array_off(gen, i));
+	/* R7 contains the error code from sys_bpf. Copy it into R0 and exit. */
+	emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_7));
+	emit(gen, BPF_EXIT_INSN());
+}
+
+static int add_data(struct bpf_gen *gen, const void *data, __u32 size)
+{
+	__u64 zero = 0;
+	__u32 size8;
+	void *prev;
+
+	if (size > INT32_MAX) {
+		gen->error = -ERANGE;
+		return 0;
+	}
+	size8 = roundup(size, 8);
+
+	if (realloc_data_buf(gen, size8))
+		return 0;
+	prev = gen->data_cur;
+	if (data) {
+		memcpy(gen->data_cur, data, size);
+		memcpy(gen->data_cur + size, &zero, size8 - size);
+	} else {
+		memset(gen->data_cur, 0, size8);
+	}
+	gen->data_cur += size8;
+	return prev - gen->data_start;
+}
+
+/* Get index for map_fd/btf_fd slot in reserved fd_array, or in data relative
+ * to start of fd_array. Caller can decide if it is usable or not.
+ */
+static int add_map_fd(struct bpf_gen *gen)
+{
+	if (gen->nr_maps == MAX_USED_MAPS) {
+		pr_warn("Total maps exceeds %d\n", MAX_USED_MAPS);
+		gen->error = -E2BIG;
+		return 0;
+	}
+	return gen->nr_maps++;
+}
+
+static int add_kfunc_btf_fd(struct bpf_gen *gen)
+{
+	int cur;
+
+	if (gen->nr_fd_array == MAX_KFUNC_DESCS) {
+		cur = add_data(gen, NULL, sizeof(int));
+		return (cur - gen->fd_array) / sizeof(int);
+	}
+	return MAX_USED_MAPS + gen->nr_fd_array++;
+}
+
+static int insn_bytes_to_bpf_size(__u32 sz)
+{
+	switch (sz) {
+	case 8: return BPF_DW;
+	case 4: return BPF_W;
+	case 2: return BPF_H;
+	case 1: return BPF_B;
+	default: return -1;
+	}
+}
+
+/* *(u64 *)(blob + off) = (u64)(void *)(blob + data) */
+static void emit_rel_store(struct bpf_gen *gen, int off, int data)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, data));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_blob2blob(struct bpf_gen *gen, int off, int size, int blob_off)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_off));
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_2, 0));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_blob2ctx(struct bpf_gen *gen, int ctx_off, int size, int blob_off)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_off));
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_1, 0));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off));
+}
+
+static void move_ctx2blob(struct bpf_gen *gen, int off, int size, int ctx_off,
+				   bool check_non_zero)
+{
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_6, ctx_off));
+	if (check_non_zero)
+		/* If value in ctx is zero don't update the blob.
+		 * For example: when ctx->map.max_entries == 0, keep default max_entries from bpf.c
+		 */
+		emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_stack2blob(struct bpf_gen *gen, int off, int size, int stack_off)
+{
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
+}
+
+static void move_stack2ctx(struct bpf_gen *gen, int ctx_off, int size, int stack_off)
+{
+	emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off));
+	emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off));
+}
+
+static void emit_sys_bpf(struct bpf_gen *gen, int cmd, int attr, int attr_size)
+{
+	emit(gen, BPF_MOV64_IMM(BPF_REG_1, cmd));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, attr));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, attr_size));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_bpf));
+	/* remember the result in R7 */
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+}
+
+static bool is_simm16(__s64 value)
+{
+	return value == (__s64)(__s16)value;
+}
+
+static void emit_check_err(struct bpf_gen *gen)
+{
+	__s64 off = -(gen->insn_cur - gen->insn_start - gen->cleanup_label) / 8 - 1;
+
+	/* R7 contains result of last sys_bpf command.
+	 * if (R7 < 0) goto cleanup;
+	 */
+	if (is_simm16(off)) {
+		emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, off));
+	} else {
+		gen->error = -ERANGE;
+	}
+}
+
+/* reg1 and reg2 should not be R1 - R5. They can be R0, R6 - R10 */
+static void emit_debug(struct bpf_gen *gen, int reg1, int reg2,
+		       const char *fmt, va_list args)
+{
+	char buf[1024];
+	int addr, len, ret;
+
+	if (!gen->log_level)
+		return;
+	ret = vsnprintf(buf, sizeof(buf), fmt, args);
+	if (ret < 1024 - 7 && reg1 >= 0 && reg2 < 0)
+		/* The special case to accommodate common debug_ret():
+		 * to avoid specifying BPF_REG_7 and adding " r=%%d" to
+		 * prints explicitly.
+		 */
+		strcat(buf, " r=%d");
+	len = strlen(buf) + 1;
+	addr = add_data(gen, buf, len);
+
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, addr));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	if (reg1 >= 0)
+		emit(gen, BPF_MOV64_REG(BPF_REG_3, reg1));
+	if (reg2 >= 0)
+		emit(gen, BPF_MOV64_REG(BPF_REG_4, reg2));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_trace_printk));
+}
+
+static void debug_regs(struct bpf_gen *gen, int reg1, int reg2, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	emit_debug(gen, reg1, reg2, fmt, args);
+	va_end(args);
+}
+
+static void debug_ret(struct bpf_gen *gen, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	emit_debug(gen, BPF_REG_7, -1, fmt, args);
+	va_end(args);
+}
+
+static void __emit_sys_close(struct bpf_gen *gen)
+{
+	emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0,
+			      /* 2 is the number of the following insns
+			       * * 6 is additional insns in debug_regs
+			       */
+			      2 + (gen->log_level ? 6 : 0)));
+	emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_1));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close));
+	debug_regs(gen, BPF_REG_9, BPF_REG_0, "close(%%d) = %%d");
+}
+
+static void emit_sys_close_stack(struct bpf_gen *gen, int stack_off)
+{
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, stack_off));
+	__emit_sys_close(gen);
+}
+
+static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off)
+{
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_off));
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0));
+	__emit_sys_close(gen);
+}
+
+int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps)
+{
+	int i;
+
+	if (nr_progs < gen->nr_progs || nr_maps != gen->nr_maps) {
+		pr_warn("nr_progs %d/%u nr_maps %d/%u mismatch\n",
+			nr_progs, gen->nr_progs, nr_maps, gen->nr_maps);
+		gen->error = -EFAULT;
+		return gen->error;
+	}
+	emit_sys_close_stack(gen, stack_off(btf_fd));
+	for (i = 0; i < gen->nr_progs; i++)
+		move_stack2ctx(gen,
+			       sizeof(struct bpf_loader_ctx) +
+			       sizeof(struct bpf_map_desc) * gen->nr_maps +
+			       sizeof(struct bpf_prog_desc) * i +
+			       offsetof(struct bpf_prog_desc, prog_fd), 4,
+			       stack_off(prog_fd[i]));
+	for (i = 0; i < gen->nr_maps; i++)
+		move_blob2ctx(gen,
+			      sizeof(struct bpf_loader_ctx) +
+			      sizeof(struct bpf_map_desc) * i +
+			      offsetof(struct bpf_map_desc, map_fd), 4,
+			      blob_fd_array_off(gen, i));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_0, 0));
+	emit(gen, BPF_EXIT_INSN());
+	if (!gen->error) {
+		struct gen_loader_opts *opts = gen->opts;
+
+		opts->insns = gen->insn_start;
+		opts->insns_sz = gen->insn_cur - gen->insn_start;
+		opts->data = gen->data_start;
+		opts->data_sz = gen->data_cur - gen->data_start;
+
+		/* use target endianness for embedded loader */
+		if (gen->swapped_endian) {
+			struct bpf_insn *insn = (struct bpf_insn *)opts->insns;
+			int insn_cnt = opts->insns_sz / sizeof(struct bpf_insn);
+
+			for (i = 0; i < insn_cnt; i++)
+				bpf_insn_bswap(insn++);
+		}
+	}
+	pr_debug("gen: finish %s\n", errstr(gen->error));
+	return gen->error;
+}
+
+void bpf_gen__free(struct bpf_gen *gen)
+{
+	if (!gen)
+		return;
+	free(gen->data_start);
+	free(gen->insn_start);
+	free(gen);
+}
+
+/*
+ * Fields of bpf_attr are set to values in native byte-order before being
+ * written to the target-bound data blob, and may need endian conversion.
+ * This macro allows providing the correct value in situ more simply than
+ * writing a separate converter for *all fields* of *all records* included
+ * in union bpf_attr. Note that sizeof(rval) should match the assignment
+ * target to avoid runtime problems.
+ */
+#define tgt_endian(rval) ({					\
+	typeof(rval) _val = (rval);				\
+	if (gen->swapped_endian) {				\
+		switch (sizeof(_val)) {				\
+		case 1: break;					\
+		case 2: _val = bswap_16(_val); break;		\
+		case 4: _val = bswap_32(_val); break;		\
+		case 8: _val = bswap_64(_val); break;		\
+		default: pr_warn("unsupported bswap size!\n");	\
+		}						\
+	}							\
+	_val;							\
+})
+
+void bpf_gen__load_btf(struct bpf_gen *gen, const void *btf_raw_data,
+		       __u32 btf_raw_size)
+{
+	int attr_size = offsetofend(union bpf_attr, btf_log_level);
+	int btf_data, btf_load_attr;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	btf_data = add_data(gen, btf_raw_data, btf_raw_size);
+
+	attr.btf_size = tgt_endian(btf_raw_size);
+	btf_load_attr = add_data(gen, &attr, attr_size);
+	pr_debug("gen: load_btf: off %d size %u, attr: off %d size %d\n",
+		 btf_data, btf_raw_size, btf_load_attr, attr_size);
+
+	/* populate union bpf_attr with user provided log details */
+	move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_level), 4,
+		      offsetof(struct bpf_loader_ctx, log_level), false);
+	move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_size), 4,
+		      offsetof(struct bpf_loader_ctx, log_size), false);
+	move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_buf), 8,
+		      offsetof(struct bpf_loader_ctx, log_buf), false);
+	/* populate union bpf_attr with a pointer to the BTF data */
+	emit_rel_store(gen, attr_field(btf_load_attr, btf), btf_data);
+	/* emit BTF_LOAD command */
+	emit_sys_bpf(gen, BPF_BTF_LOAD, btf_load_attr, attr_size);
+	debug_ret(gen, "btf_load size %d", btf_raw_size);
+	emit_check_err(gen);
+	/* remember btf_fd in the stack, if successful */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, stack_off(btf_fd)));
+}
+
+void bpf_gen__map_create(struct bpf_gen *gen,
+			 enum bpf_map_type map_type,
+			 const char *map_name,
+			 __u32 key_size, __u32 value_size, __u32 max_entries,
+			 struct bpf_map_create_opts *map_attr, int map_idx)
+{
+	int attr_size = offsetofend(union bpf_attr, map_extra);
+	bool close_inner_map_fd = false;
+	int map_create_attr, idx;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	attr.map_type = tgt_endian(map_type);
+	attr.key_size = tgt_endian(key_size);
+	attr.value_size = tgt_endian(value_size);
+	attr.map_flags = tgt_endian(map_attr->map_flags);
+	attr.map_extra = tgt_endian(map_attr->map_extra);
+	if (map_name)
+		libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name));
+	attr.numa_node = tgt_endian(map_attr->numa_node);
+	attr.map_ifindex = tgt_endian(map_attr->map_ifindex);
+	attr.max_entries = tgt_endian(max_entries);
+	attr.btf_key_type_id = tgt_endian(map_attr->btf_key_type_id);
+	attr.btf_value_type_id = tgt_endian(map_attr->btf_value_type_id);
+
+	map_create_attr = add_data(gen, &attr, attr_size);
+	pr_debug("gen: map_create: %s idx %d type %u value_type_id %u, attr: off %d size %d\n",
+		 map_name, map_idx, map_type, map_attr->btf_value_type_id,
+		 map_create_attr, attr_size);
+
+	if (map_attr->btf_value_type_id)
+		/* populate union bpf_attr with btf_fd saved in the stack earlier */
+		move_stack2blob(gen, attr_field(map_create_attr, btf_fd), 4,
+				stack_off(btf_fd));
+	switch (map_type) {
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+		move_stack2blob(gen, attr_field(map_create_attr, inner_map_fd), 4,
+				stack_off(inner_map_fd));
+		close_inner_map_fd = true;
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * Conditionally update max_entries from the host-supplied loader
+	 * ctx. This sizes the map at runtime, but for a signed loader
+	 * (gen_hash) it would let an untrusted host re-dimension the
+	 * program's maps, outside what the signature attests to: the
+	 * metadata blob is covered by the program signature and verified
+	 * by the kernel at load time. Keep the signer-provided max_entries
+	 * baked into the blob in that case.
+	 */
+	if (map_idx >= 0 && !OPTS_GET(gen->opts, gen_hash, false))
+		move_ctx2blob(gen, attr_field(map_create_attr, max_entries), 4,
+			      sizeof(struct bpf_loader_ctx) +
+			      sizeof(struct bpf_map_desc) * map_idx +
+			      offsetof(struct bpf_map_desc, max_entries),
+			      true /* check that max_entries != 0 */);
+
+	/* emit MAP_CREATE command */
+	emit_sys_bpf(gen, BPF_MAP_CREATE, map_create_attr, attr_size);
+	debug_ret(gen, "map_create %s idx %d type %d value_size %d value_btf_id %d",
+		  map_name, map_idx, map_type, value_size,
+		  map_attr->btf_value_type_id);
+	emit_check_err(gen);
+	/* remember map_fd in the stack, if successful */
+	if (map_idx < 0) {
+		/* This bpf_gen__map_create() function is called with map_idx >= 0
+		 * for all maps that libbpf loading logic tracks.
+		 * It's called with -1 to create an inner map.
+		 */
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
+				      stack_off(inner_map_fd)));
+	} else if (map_idx != gen->nr_maps) {
+		gen->error = -EDOM; /* internal bug */
+		return;
+	} else {
+		/* add_map_fd does gen->nr_maps++ */
+		idx = add_map_fd(gen);
+		emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+						 0, 0, 0, blob_fd_array_off(gen, idx)));
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_7, 0));
+	}
+	if (close_inner_map_fd)
+		emit_sys_close_stack(gen, stack_off(inner_map_fd));
+}
+
+void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *attach_name,
+				   enum bpf_attach_type type)
+{
+	const char *prefix;
+	int kind, ret;
+
+	btf_get_kernel_prefix_kind(type, &prefix, &kind);
+	gen->attach_kind = kind;
+	ret = snprintf(gen->attach_target, sizeof(gen->attach_target), "%s%s",
+		       prefix, attach_name);
+	if (ret >= sizeof(gen->attach_target))
+		gen->error = -ENOSPC;
+}
+
+static void emit_find_attach_target(struct bpf_gen *gen)
+{
+	int name, len = strlen(gen->attach_target) + 1;
+
+	pr_debug("gen: find_attach_tgt %s %d\n", gen->attach_target, gen->attach_kind);
+	name = add_data(gen, gen->attach_target, len);
+
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, gen->attach_kind));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "find_by_name_kind(%s,%d)",
+		  gen->attach_target, gen->attach_kind);
+	emit_check_err(gen);
+	/* if successful, btf_id is in lower 32-bit of R7 and
+	 * btf_obj_fd is in upper 32-bit
+	 */
+}
+
+void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
+			    bool is_typeless, bool is_ld64, int kind, int insn_idx)
+{
+	struct ksym_relo_desc *relo;
+
+	relo = libbpf_reallocarray(gen->relos, gen->relo_cnt + 1, sizeof(*relo));
+	if (!relo) {
+		gen->error = -ENOMEM;
+		return;
+	}
+	gen->relos = relo;
+	relo += gen->relo_cnt;
+	relo->name = name;
+	relo->is_weak = is_weak;
+	relo->is_typeless = is_typeless;
+	relo->is_ld64 = is_ld64;
+	relo->kind = kind;
+	relo->insn_idx = insn_idx;
+	gen->relo_cnt++;
+}
+
+/* returns existing ksym_desc with ref incremented, or inserts a new one */
+static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	struct ksym_desc *kdesc;
+	int i;
+
+	for (i = 0; i < gen->nr_ksyms; i++) {
+		kdesc = &gen->ksyms[i];
+		if (kdesc->kind == relo->kind && kdesc->is_ld64 == relo->is_ld64 &&
+		    !strcmp(kdesc->name, relo->name)) {
+			kdesc->ref++;
+			return kdesc;
+		}
+	}
+	kdesc = libbpf_reallocarray(gen->ksyms, gen->nr_ksyms + 1, sizeof(*kdesc));
+	if (!kdesc) {
+		gen->error = -ENOMEM;
+		return NULL;
+	}
+	gen->ksyms = kdesc;
+	kdesc = &gen->ksyms[gen->nr_ksyms++];
+	kdesc->name = relo->name;
+	kdesc->kind = relo->kind;
+	kdesc->ref = 1;
+	kdesc->off = 0;
+	kdesc->insn = 0;
+	kdesc->is_ld64 = relo->is_ld64;
+	return kdesc;
+}
+
+/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
+ * Returns result in BPF_REG_7
+ */
+static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	int name_off, len = strlen(relo->name) + 1;
+
+	name_off = add_data(gen, relo->name, len);
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name_off));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, relo->kind));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind);
+}
+
+/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
+ * Returns result in BPF_REG_7
+ * Returns u64 symbol addr in BPF_REG_9
+ */
+static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+	int name_off, len = strlen(relo->name) + 1, res_off;
+
+	name_off = add_data(gen, relo->name, len);
+	res_off = add_data(gen, NULL, 8); /* res is u64 */
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, name_off));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+	emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, res_off));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4));
+	emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name));
+	emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0));
+	emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+	debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind);
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ *
+ * We need to reuse BTF fd for same symbol otherwise each relocation takes a new
+ * index, while kernel limits total kfunc BTFs to 256. For duplicate symbols,
+ * this would mean a new BTF fd index for each entry. By pairing symbol name
+ * with index, we get the insn->imm, insn->off pairing that kernel uses for
+ * kfunc_tab, which becomes the effective limit even though all of them may
+ * share same index in fd_array (such that kfunc_btf_tab has 1 element).
+ */
+static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+	int btf_fd_idx;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing bpf_insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, off), 2,
+			       kdesc->insn + offsetof(struct bpf_insn, off));
+		goto log;
+	}
+	/* remember insn offset, so we can copy BTF ID and FD later */
+	kdesc->insn = insn;
+	emit_bpf_find_by_name_kind(gen, relo);
+	if (!relo->is_weak)
+		emit_check_err(gen);
+	/* get index in fd_array to store BTF FD at */
+	btf_fd_idx = add_kfunc_btf_fd(gen);
+	if (btf_fd_idx > INT16_MAX) {
+		pr_warn("BTF fd off %d for kfunc %s exceeds INT16_MAX, cannot process relocation\n",
+			btf_fd_idx, relo->name);
+		gen->error = -E2BIG;
+		return;
+	}
+	kdesc->off = btf_fd_idx;
+	/* jump to success case */
+	emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
+	/* set value for imm, off as 0 */
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
+	/* skip success case for ret < 0 */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 10));
+	/* store btf_id into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
+	/* obtain fd in BPF_REG_9 */
+	emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7));
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
+	/* load fd_array slot pointer */
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx)));
+	/* store BTF fd in slot, 0 for vmlinux */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
+	/* jump to insn[insn_idx].off store if fd denotes module BTF */
+	emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
+	/* set the default value for off */
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
+	/* skip BTF fd store for vmlinux BTF */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
+	/* store index into insn[insn_idx].off */
+	emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx));
+log:
+	if (!gen->log_level)
+		return;
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
+			      offsetof(struct bpf_insn, imm)));
+	emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8,
+			      offsetof(struct bpf_insn, off)));
+	debug_regs(gen, BPF_REG_7, BPF_REG_9, " func (%s:count=%d): imm: %%d, off: %%d",
+		   relo->name, kdesc->ref);
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+					 0, 0, 0, blob_fd_array_off(gen, kdesc->off)));
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_0, 0));
+	debug_regs(gen, BPF_REG_9, -1, " func (%s:count=%d): btf_fd",
+		   relo->name, kdesc->ref);
+}
+
+static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo,
+			       int ref)
+{
+	if (!gen->log_level)
+		return;
+	emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
+			      offsetof(struct bpf_insn, imm)));
+	emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
+			      offsetof(struct bpf_insn, imm)));
+	debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d",
+		   relo->is_typeless, relo->is_weak, relo->name, ref);
+	emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+	debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg",
+		   relo->is_typeless, relo->is_weak, relo->name, ref);
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ */
+static void emit_relo_ksym_typeless(struct bpf_gen *gen,
+				    struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing ldimm64 insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
+		goto log;
+	}
+	/* remember insn offset, so we can copy ksym addr later */
+	kdesc->insn = insn;
+	/* skip typeless ksym_desc in fd closing loop in cleanup_relos */
+	kdesc->typeless = true;
+	emit_bpf_kallsyms_lookup_name(gen, relo);
+	emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1));
+	emit_check_err(gen);
+	/* store lower half of addr into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm)));
+	/* store upper half of addr into insn[insn_idx + 1].imm */
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9,
+		      sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
+log:
+	emit_ksym_relo_log(gen, relo, kdesc->ref);
+}
+
+static __u32 src_reg_mask(struct bpf_gen *gen)
+{
+#if defined(__LITTLE_ENDIAN_BITFIELD) /* src_reg,dst_reg,... */
+	return gen->swapped_endian ? 0xf0 : 0x0f;
+#elif defined(__BIG_ENDIAN_BITFIELD) /* dst_reg,src_reg,... */
+	return gen->swapped_endian ? 0x0f : 0xf0;
+#else
+#error "Unsupported bit endianness, cannot proceed"
+#endif
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ */
+static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
+{
+	struct ksym_desc *kdesc;
+	__u32 reg_mask;
+
+	kdesc = get_ksym_desc(gen, relo);
+	if (!kdesc)
+		return;
+	/* try to copy from existing ldimm64 insn */
+	if (kdesc->ref > 1) {
+		move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
+		move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+			       kdesc->insn + offsetof(struct bpf_insn, imm));
+		/* jump over src_reg adjustment if imm (btf_id) is not 0, reuse BPF_REG_0 from move_blob2blob
+		 * If btf_id is zero, clear BPF_PSEUDO_BTF_ID flag in src_reg of ld_imm64 insn
+		 */
+		emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3));
+		goto clear_src_reg;
+	}
+	/* remember insn offset, so we can copy BTF ID and FD later */
+	kdesc->insn = insn;
+	emit_bpf_find_by_name_kind(gen, relo);
+	if (!relo->is_weak)
+		emit_check_err(gen);
+	/* jump to success case */
+	emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
+	/* set values for insn[insn_idx].imm, insn[insn_idx + 1].imm as 0 */
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
+	emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 0));
+	/* skip success case for ret < 0 */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
+	/* store btf_id into insn[insn_idx].imm */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
+	/* store btf_obj_fd into insn[insn_idx + 1].imm */
+	emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7,
+			      sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
+	/* skip src_reg adjustment */
+	emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 3));
+clear_src_reg:
+	/* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */
+	reg_mask = src_reg_mask(gen);
+	emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+	emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask));
+	emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code)));
+
+	emit_ksym_relo_log(gen, relo, kdesc->ref);
+}
+
+void bpf_gen__record_relo_core(struct bpf_gen *gen,
+			       const struct bpf_core_relo *core_relo)
+{
+	struct bpf_core_relo *relos;
+
+	relos = libbpf_reallocarray(gen->core_relos, gen->core_relo_cnt + 1, sizeof(*relos));
+	if (!relos) {
+		gen->error = -ENOMEM;
+		return;
+	}
+	gen->core_relos = relos;
+	relos += gen->core_relo_cnt;
+	memcpy(relos, core_relo, sizeof(*relos));
+	gen->core_relo_cnt++;
+}
+
+static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns)
+{
+	int insn;
+
+	pr_debug("gen: emit_relo (%d): %s at %d %s\n",
+		 relo->kind, relo->name, relo->insn_idx, relo->is_ld64 ? "ld64" : "call");
+	insn = insns + sizeof(struct bpf_insn) * relo->insn_idx;
+	emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn));
+	if (relo->is_ld64) {
+		if (relo->is_typeless)
+			emit_relo_ksym_typeless(gen, relo, insn);
+		else
+			emit_relo_ksym_btf(gen, relo, insn);
+	} else {
+		emit_relo_kfunc_btf(gen, relo, insn);
+	}
+}
+
+static void emit_relos(struct bpf_gen *gen, int insns)
+{
+	int i;
+
+	for (i = 0; i < gen->relo_cnt; i++)
+		emit_relo(gen, gen->relos + i, insns);
+}
+
+static void cleanup_core_relo(struct bpf_gen *gen)
+{
+	if (!gen->core_relo_cnt)
+		return;
+	free(gen->core_relos);
+	gen->core_relo_cnt = 0;
+	gen->core_relos = NULL;
+}
+
+static void cleanup_relos(struct bpf_gen *gen, int insns)
+{
+	struct ksym_desc *kdesc;
+	int i, insn;
+
+	for (i = 0; i < gen->nr_ksyms; i++) {
+		kdesc = &gen->ksyms[i];
+		/* only close fds for typed ksyms and kfuncs */
+		if (kdesc->is_ld64 && !kdesc->typeless) {
+			/* close fd recorded in insn[insn_idx + 1].imm */
+			insn = kdesc->insn;
+			insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm);
+			emit_sys_close_blob(gen, insn);
+		} else if (!kdesc->is_ld64) {
+			emit_sys_close_blob(gen, blob_fd_array_off(gen, kdesc->off));
+			if (kdesc->off < MAX_FD_ARRAY_SZ)
+				gen->nr_fd_array--;
+		}
+	}
+	if (gen->nr_ksyms) {
+		free(gen->ksyms);
+		gen->nr_ksyms = 0;
+		gen->ksyms = NULL;
+	}
+	if (gen->relo_cnt) {
+		free(gen->relos);
+		gen->relo_cnt = 0;
+		gen->relos = NULL;
+	}
+	cleanup_core_relo(gen);
+}
+
+/* Convert func, line, and core relo info blobs to target endianness */
+static void info_blob_bswap(struct bpf_gen *gen, int func_info, int line_info,
+			    int core_relos, struct bpf_prog_load_opts *load_attr)
+{
+	struct bpf_func_info *fi = gen->data_start + func_info;
+	struct bpf_line_info *li = gen->data_start + line_info;
+	struct bpf_core_relo *cr = gen->data_start + core_relos;
+	int i;
+
+	for (i = 0; i < load_attr->func_info_cnt; i++)
+		bpf_func_info_bswap(fi++);
+
+	for (i = 0; i < load_attr->line_info_cnt; i++)
+		bpf_line_info_bswap(li++);
+
+	for (i = 0; i < gen->core_relo_cnt; i++)
+		bpf_core_relo_bswap(cr++);
+}
+
+void bpf_gen__prog_load(struct bpf_gen *gen,
+			enum bpf_prog_type prog_type, const char *prog_name,
+			const char *license, struct bpf_insn *insns, size_t insn_cnt,
+			struct bpf_prog_load_opts *load_attr, int prog_idx)
+{
+	int func_info_tot_sz = load_attr->func_info_cnt *
+			       load_attr->func_info_rec_size;
+	int line_info_tot_sz = load_attr->line_info_cnt *
+			       load_attr->line_info_rec_size;
+	int core_relo_tot_sz = gen->core_relo_cnt *
+			       sizeof(struct bpf_core_relo);
+	int prog_load_attr, license_off, insns_off, func_info, line_info, core_relos;
+	int attr_size = offsetofend(union bpf_attr, core_relo_rec_size);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	/* add license string to blob of bytes */
+	license_off = add_data(gen, license, strlen(license) + 1);
+	/* add insns to blob of bytes */
+	insns_off = add_data(gen, insns, insn_cnt * sizeof(struct bpf_insn));
+	pr_debug("gen: prog_load: prog_idx %d type %u insn off %d insns_cnt %zu license off %d\n",
+		 prog_idx, prog_type, insns_off, insn_cnt, license_off);
+
+	/* convert blob insns to target endianness */
+	if (gen->swapped_endian && !gen->error) {
+		struct bpf_insn *insn = gen->data_start + insns_off;
+		int i;
+
+		for (i = 0; i < insn_cnt; i++, insn++)
+			bpf_insn_bswap(insn);
+	}
+
+	attr.prog_type = tgt_endian(prog_type);
+	attr.expected_attach_type = tgt_endian(load_attr->expected_attach_type);
+	attr.attach_btf_id = tgt_endian(load_attr->attach_btf_id);
+	attr.prog_ifindex = tgt_endian(load_attr->prog_ifindex);
+	attr.kern_version = 0;
+	attr.insn_cnt = tgt_endian((__u32)insn_cnt);
+	attr.prog_flags = tgt_endian(load_attr->prog_flags);
+
+	attr.func_info_rec_size = tgt_endian(load_attr->func_info_rec_size);
+	attr.func_info_cnt = tgt_endian(load_attr->func_info_cnt);
+	func_info = add_data(gen, load_attr->func_info, func_info_tot_sz);
+	pr_debug("gen: prog_load: func_info: off %d cnt %u rec size %u\n",
+		 func_info, load_attr->func_info_cnt,
+		 load_attr->func_info_rec_size);
+
+	attr.line_info_rec_size = tgt_endian(load_attr->line_info_rec_size);
+	attr.line_info_cnt = tgt_endian(load_attr->line_info_cnt);
+	line_info = add_data(gen, load_attr->line_info, line_info_tot_sz);
+	pr_debug("gen: prog_load: line_info: off %d cnt %u rec size %u\n",
+		 line_info, load_attr->line_info_cnt,
+		 load_attr->line_info_rec_size);
+
+	attr.core_relo_rec_size = tgt_endian((__u32)sizeof(struct bpf_core_relo));
+	attr.core_relo_cnt = tgt_endian(gen->core_relo_cnt);
+	core_relos = add_data(gen, gen->core_relos, core_relo_tot_sz);
+	pr_debug("gen: prog_load: core_relos: off %d cnt %d rec size %zu\n",
+		 core_relos, gen->core_relo_cnt,
+		 sizeof(struct bpf_core_relo));
+
+	/* convert all info blobs to target endianness */
+	if (gen->swapped_endian && !gen->error)
+		info_blob_bswap(gen, func_info, line_info, core_relos, load_attr);
+
+	libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
+	prog_load_attr = add_data(gen, &attr, attr_size);
+	pr_debug("gen: prog_load: attr: off %d size %d\n",
+		 prog_load_attr, attr_size);
+
+	/* populate union bpf_attr with a pointer to license */
+	emit_rel_store(gen, attr_field(prog_load_attr, license), license_off);
+
+	/* populate union bpf_attr with a pointer to instructions */
+	emit_rel_store(gen, attr_field(prog_load_attr, insns), insns_off);
+
+	/* populate union bpf_attr with a pointer to func_info */
+	emit_rel_store(gen, attr_field(prog_load_attr, func_info), func_info);
+
+	/* populate union bpf_attr with a pointer to line_info */
+	emit_rel_store(gen, attr_field(prog_load_attr, line_info), line_info);
+
+	/* populate union bpf_attr with a pointer to core_relos */
+	emit_rel_store(gen, attr_field(prog_load_attr, core_relos), core_relos);
+
+	/* populate union bpf_attr fd_array with a pointer to data where map_fds are saved */
+	emit_rel_store(gen, attr_field(prog_load_attr, fd_array), gen->fd_array);
+
+	/* populate union bpf_attr with user provided log details */
+	move_ctx2blob(gen, attr_field(prog_load_attr, log_level), 4,
+		      offsetof(struct bpf_loader_ctx, log_level), false);
+	move_ctx2blob(gen, attr_field(prog_load_attr, log_size), 4,
+		      offsetof(struct bpf_loader_ctx, log_size), false);
+	move_ctx2blob(gen, attr_field(prog_load_attr, log_buf), 8,
+		      offsetof(struct bpf_loader_ctx, log_buf), false);
+	/* populate union bpf_attr with btf_fd saved in the stack earlier */
+	move_stack2blob(gen, attr_field(prog_load_attr, prog_btf_fd), 4,
+			stack_off(btf_fd));
+	if (gen->attach_kind) {
+		emit_find_attach_target(gen);
+		/* populate union bpf_attr with btf_id and btf_obj_fd found by helper */
+		emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
+						 0, 0, 0, prog_load_attr));
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
+				      offsetof(union bpf_attr, attach_btf_id)));
+		emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
+		emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
+				      offsetof(union bpf_attr, attach_btf_obj_fd)));
+	}
+	emit_relos(gen, insns_off);
+	/* emit PROG_LOAD command */
+	emit_sys_bpf(gen, BPF_PROG_LOAD, prog_load_attr, attr_size);
+	debug_ret(gen, "prog_load %s insn_cnt %d", attr.prog_name, attr.insn_cnt);
+	/* successful or not, close btf module FDs used in extern ksyms and attach_btf_obj_fd */
+	cleanup_relos(gen, insns_off);
+	if (gen->attach_kind) {
+		emit_sys_close_blob(gen,
+				    attr_field(prog_load_attr, attach_btf_obj_fd));
+		gen->attach_kind = 0;
+	}
+	emit_check_err(gen);
+	/* remember prog_fd in the stack, if successful */
+	emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
+			      stack_off(prog_fd[gen->nr_progs])));
+	gen->nr_progs++;
+}
+
+void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
+			      __u32 value_size, __u64 flags)
+{
+	int attr_size = offsetofend(union bpf_attr, flags);
+	int map_update_attr, value, key;
+	union bpf_attr attr;
+	int zero = 0;
+
+	memset(&attr, 0, attr_size);
+	attr.flags = tgt_endian(flags);
+
+	value = add_data(gen, pvalue, value_size);
+	key = add_data(gen, &zero, sizeof(zero));
+
+	/*
+	 * if (map_desc[map_idx].initial_value) {
+	 *    if (ctx->flags & BPF_SKEL_KERNEL)
+	 *        bpf_probe_read_kernel(value, value_size, initial_value);
+	 *    else
+	 *        bpf_copy_from_user(value, value_size, initial_value);
+	 * }
+	 *
+	 * The runtime initial_value comes from the host-supplied loader
+	 * ctx and would overwrite the blob value that the program signature
+	 * covers and the kernel verifies at load time. For a signed loader
+	 * (gen_hash) the attested blob value must be authoritative, so skip
+	 * the override and leave the signed value in place.
+	 */
+	if (!OPTS_GET(gen->opts, gen_hash, false)) {
+		emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6,
+				      sizeof(struct bpf_loader_ctx) +
+				      sizeof(struct bpf_map_desc) * map_idx +
+				      offsetof(struct bpf_map_desc, initial_value)));
+		emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8));
+		emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+						 0, 0, 0, value));
+		emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size));
+		emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
+				      offsetof(struct bpf_loader_ctx, flags)));
+		emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2));
+		emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user));
+		emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
+		emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
+	}
+
+	map_update_attr = add_data(gen, &attr, attr_size);
+	pr_debug("gen: map_update_elem: idx %d, value: off %d size %u, attr: off %d size %d\n",
+		 map_idx, value, value_size, map_update_attr, attr_size);
+	move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
+		       blob_fd_array_off(gen, map_idx));
+	emit_rel_store(gen, attr_field(map_update_attr, key), key);
+	emit_rel_store(gen, attr_field(map_update_attr, value), value);
+	/* emit MAP_UPDATE_ELEM command */
+	emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size);
+	debug_ret(gen, "update_elem idx %d value_size %d", map_idx, value_size);
+	emit_check_err(gen);
+}
+
+void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int slot,
+				 int inner_map_idx)
+{
+	int attr_size = offsetofend(union bpf_attr, flags);
+	int map_update_attr, key;
+	union bpf_attr attr;
+	int tgt_slot;
+
+	memset(&attr, 0, attr_size);
+
+	tgt_slot = tgt_endian(slot);
+	key = add_data(gen, &tgt_slot, sizeof(tgt_slot));
+
+	map_update_attr = add_data(gen, &attr, attr_size);
+	pr_debug("gen: populate_outer_map: outer %d key %d inner %d, attr: off %d size %d\n",
+		 outer_map_idx, slot, inner_map_idx, map_update_attr, attr_size);
+	move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
+		       blob_fd_array_off(gen, outer_map_idx));
+	emit_rel_store(gen, attr_field(map_update_attr, key), key);
+	emit_rel_store(gen, attr_field(map_update_attr, value),
+		       blob_fd_array_off(gen, inner_map_idx));
+
+	/* emit MAP_UPDATE_ELEM command */
+	emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size);
+	debug_ret(gen, "populate_outer_map outer %d key %d inner %d",
+		  outer_map_idx, slot, inner_map_idx);
+	emit_check_err(gen);
+}
+
+void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx)
+{
+	int attr_size = offsetofend(union bpf_attr, map_fd);
+	int map_freeze_attr;
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_size);
+	map_freeze_attr = add_data(gen, &attr, attr_size);
+	pr_debug("gen: map_freeze: idx %d, attr: off %d size %d\n",
+		 map_idx, map_freeze_attr, attr_size);
+	move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), 4,
+		       blob_fd_array_off(gen, map_idx));
+	/* emit MAP_FREEZE command */
+	emit_sys_bpf(gen, BPF_MAP_FREEZE, map_freeze_attr, attr_size);
+	debug_ret(gen, "map_freeze");
+	emit_check_err(gen);
+}
diff --git a/tools/lib/bpf/hashmap.c b/tools/lib/bpf/hashmap.c
new file mode 100644
index 000000000..140ee4055
--- /dev/null
+++ b/tools/lib/bpf/hashmap.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * Generic non-thread safe hash map implementation.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <linux/err.h>
+#include "hashmap.h"
+
+/* make sure libbpf doesn't use kernel-only integer typedefs */
+#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+
+/* prevent accidental re-addition of reallocarray() */
+#pragma GCC poison reallocarray
+
+/* start with 4 buckets */
+#define HASHMAP_MIN_CAP_BITS 2
+
+static void hashmap_add_entry(struct hashmap_entry **pprev,
+			      struct hashmap_entry *entry)
+{
+	entry->next = *pprev;
+	*pprev = entry;
+}
+
+static void hashmap_del_entry(struct hashmap_entry **pprev,
+			      struct hashmap_entry *entry)
+{
+	*pprev = entry->next;
+	entry->next = NULL;
+}
+
+void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
+		   hashmap_equal_fn equal_fn, void *ctx)
+{
+	map->hash_fn = hash_fn;
+	map->equal_fn = equal_fn;
+	map->ctx = ctx;
+
+	map->buckets = NULL;
+	map->cap = 0;
+	map->cap_bits = 0;
+	map->sz = 0;
+}
+
+struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
+			     hashmap_equal_fn equal_fn,
+			     void *ctx)
+{
+	struct hashmap *map = malloc(sizeof(struct hashmap));
+
+	if (!map)
+		return ERR_PTR(-ENOMEM);
+	hashmap__init(map, hash_fn, equal_fn, ctx);
+	return map;
+}
+
+void hashmap__clear(struct hashmap *map)
+{
+	struct hashmap_entry *cur, *tmp;
+	size_t bkt;
+
+	hashmap__for_each_entry_safe(map, cur, tmp, bkt) {
+		free(cur);
+	}
+	free(map->buckets);
+	map->buckets = NULL;
+	map->cap = map->cap_bits = map->sz = 0;
+}
+
+void hashmap__free(struct hashmap *map)
+{
+	if (IS_ERR_OR_NULL(map))
+		return;
+
+	hashmap__clear(map);
+	free(map);
+}
+
+size_t hashmap__size(const struct hashmap *map)
+{
+	return map->sz;
+}
+
+size_t hashmap__capacity(const struct hashmap *map)
+{
+	return map->cap;
+}
+
+static bool hashmap_needs_to_grow(struct hashmap *map)
+{
+	/* grow if empty or more than 75% filled */
+	return (map->cap == 0) || ((map->sz + 1) * 4 / 3 > map->cap);
+}
+
+static int hashmap_grow(struct hashmap *map)
+{
+	struct hashmap_entry **new_buckets;
+	struct hashmap_entry *cur, *tmp;
+	size_t new_cap_bits, new_cap;
+	size_t h, bkt;
+
+	new_cap_bits = map->cap_bits + 1;
+	if (new_cap_bits < HASHMAP_MIN_CAP_BITS)
+		new_cap_bits = HASHMAP_MIN_CAP_BITS;
+
+	new_cap = 1UL << new_cap_bits;
+	new_buckets = calloc(new_cap, sizeof(new_buckets[0]));
+	if (!new_buckets)
+		return -ENOMEM;
+
+	hashmap__for_each_entry_safe(map, cur, tmp, bkt) {
+		h = hash_bits(map->hash_fn(cur->key, map->ctx), new_cap_bits);
+		hashmap_add_entry(&new_buckets[h], cur);
+	}
+
+	map->cap = new_cap;
+	map->cap_bits = new_cap_bits;
+	free(map->buckets);
+	map->buckets = new_buckets;
+
+	return 0;
+}
+
+static bool hashmap_find_entry(const struct hashmap *map,
+			       const long key, size_t hash,
+			       struct hashmap_entry ***pprev,
+			       struct hashmap_entry **entry)
+{
+	struct hashmap_entry *cur, **prev_ptr;
+
+	if (!map->buckets)
+		return false;
+
+	for (prev_ptr = &map->buckets[hash], cur = *prev_ptr;
+	     cur;
+	     prev_ptr = &cur->next, cur = cur->next) {
+		if (map->equal_fn(cur->key, key, map->ctx)) {
+			if (pprev)
+				*pprev = prev_ptr;
+			*entry = cur;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+int hashmap_insert(struct hashmap *map, long key, long value,
+		   enum hashmap_insert_strategy strategy,
+		   long *old_key, long *old_value)
+{
+	struct hashmap_entry *entry;
+	size_t h;
+	int err;
+
+	if (old_key)
+		*old_key = 0;
+	if (old_value)
+		*old_value = 0;
+
+	h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
+	if (strategy != HASHMAP_APPEND &&
+	    hashmap_find_entry(map, key, h, NULL, &entry)) {
+		if (old_key)
+			*old_key = entry->key;
+		if (old_value)
+			*old_value = entry->value;
+
+		if (strategy == HASHMAP_SET || strategy == HASHMAP_UPDATE) {
+			entry->key = key;
+			entry->value = value;
+			return 0;
+		} else if (strategy == HASHMAP_ADD) {
+			return -EEXIST;
+		}
+	}
+
+	if (strategy == HASHMAP_UPDATE)
+		return -ENOENT;
+
+	if (hashmap_needs_to_grow(map)) {
+		err = hashmap_grow(map);
+		if (err)
+			return err;
+		h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
+	}
+
+	entry = malloc(sizeof(struct hashmap_entry));
+	if (!entry)
+		return -ENOMEM;
+
+	entry->key = key;
+	entry->value = value;
+	hashmap_add_entry(&map->buckets[h], entry);
+	map->sz++;
+
+	return 0;
+}
+
+bool hashmap_find(const struct hashmap *map, long key, long *value)
+{
+	struct hashmap_entry *entry;
+	size_t h;
+
+	h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
+	if (!hashmap_find_entry(map, key, h, NULL, &entry))
+		return false;
+
+	if (value)
+		*value = entry->value;
+	return true;
+}
+
+bool hashmap_delete(struct hashmap *map, long key,
+		    long *old_key, long *old_value)
+{
+	struct hashmap_entry **pprev, *entry;
+	size_t h;
+
+	h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
+	if (!hashmap_find_entry(map, key, h, &pprev, &entry))
+		return false;
+
+	if (old_key)
+		*old_key = entry->key;
+	if (old_value)
+		*old_value = entry->value;
+
+	hashmap_del_entry(pprev, entry);
+	free(entry);
+	map->sz--;
+
+	return true;
+}
diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
new file mode 100644
index 000000000..0c4f155e8
--- /dev/null
+++ b/tools/lib/bpf/hashmap.h
@@ -0,0 +1,208 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * Generic non-thread safe hash map implementation.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+#ifndef __LIBBPF_HASHMAP_H
+#define __LIBBPF_HASHMAP_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <limits.h>
+
+static inline size_t hash_bits(size_t h, int bits)
+{
+	/* shuffle bits and return requested number of upper bits */
+	if (bits == 0)
+		return 0;
+
+#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
+	/* LP64 case */
+	return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
+#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
+	return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
+#else
+#	error "Unsupported size_t size"
+#endif
+}
+
+/* generic C-string hashing function */
+static inline size_t str_hash(const char *s)
+{
+	size_t h = 0;
+
+	while (*s) {
+		h = h * 31 + *s;
+		s++;
+	}
+	return h;
+}
+
+typedef size_t (*hashmap_hash_fn)(long key, void *ctx);
+typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);
+
+/*
+ * Hashmap interface is polymorphic, keys and values could be either
+ * long-sized integers or pointers, this is achieved as follows:
+ * - interface functions that operate on keys and values are hidden
+ *   behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert;
+ * - these auxiliary macros cast the key and value parameters as
+ *   long or long *, so the user does not have to specify the casts explicitly;
+ * - for pointer parameters (e.g. old_key) the size of the pointed
+ *   type is verified by hashmap_cast_ptr using _Static_assert;
+ * - when iterating using hashmap__for_each_* forms
+ *   hasmap_entry->key should be used for integer keys and
+ *   hasmap_entry->pkey should be used for pointer keys,
+ *   same goes for values.
+ */
+struct hashmap_entry {
+	union {
+		long key;
+		const void *pkey;
+	};
+	union {
+		long value;
+		void *pvalue;
+	};
+	struct hashmap_entry *next;
+};
+
+struct hashmap {
+	hashmap_hash_fn hash_fn;
+	hashmap_equal_fn equal_fn;
+	void *ctx;
+
+	struct hashmap_entry **buckets;
+	size_t cap;
+	size_t cap_bits;
+	size_t sz;
+};
+
+void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
+		   hashmap_equal_fn equal_fn, void *ctx);
+struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
+			     hashmap_equal_fn equal_fn,
+			     void *ctx);
+void hashmap__clear(struct hashmap *map);
+void hashmap__free(struct hashmap *map);
+
+size_t hashmap__size(const struct hashmap *map);
+size_t hashmap__capacity(const struct hashmap *map);
+
+/*
+ * Hashmap insertion strategy:
+ * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
+ * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
+ *   update value;
+ * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
+ *   nothing and return -ENOENT;
+ * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
+ *   This turns hashmap into a multimap by allowing multiple values to be
+ *   associated with the same key. Most useful read API for such hashmap is
+ *   hashmap__for_each_key_entry() iteration. If hashmap__find() is still
+ *   used, it will return last inserted key/value entry (first in a bucket
+ *   chain).
+ */
+enum hashmap_insert_strategy {
+	HASHMAP_ADD,
+	HASHMAP_SET,
+	HASHMAP_UPDATE,
+	HASHMAP_APPEND,
+};
+
+#define hashmap_cast_ptr(p) ({								\
+	_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) ||			\
+				sizeof(*(p)) == sizeof(long),				\
+		       #p " pointee should be a long-sized integer or a pointer");	\
+	(long *)(p);									\
+})
+
+/*
+ * hashmap__insert() adds key/value entry w/ various semantics, depending on
+ * provided strategy value. If a given key/value pair replaced already
+ * existing key/value pair, both old key and old value will be returned
+ * through old_key and old_value to allow calling code do proper memory
+ * management.
+ */
+int hashmap_insert(struct hashmap *map, long key, long value,
+		   enum hashmap_insert_strategy strategy,
+		   long *old_key, long *old_value);
+
+#define hashmap__insert(map, key, value, strategy, old_key, old_value) \
+	hashmap_insert((map), (long)(key), (long)(value), (strategy),  \
+		       hashmap_cast_ptr(old_key),		       \
+		       hashmap_cast_ptr(old_value))
+
+#define hashmap__add(map, key, value) \
+	hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)
+
+#define hashmap__set(map, key, value, old_key, old_value) \
+	hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))
+
+#define hashmap__update(map, key, value, old_key, old_value) \
+	hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))
+
+#define hashmap__append(map, key, value) \
+	hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)
+
+bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);
+
+#define hashmap__delete(map, key, old_key, old_value)		       \
+	hashmap_delete((map), (long)(key),			       \
+		       hashmap_cast_ptr(old_key),		       \
+		       hashmap_cast_ptr(old_value))
+
+bool hashmap_find(const struct hashmap *map, long key, long *value);
+
+#define hashmap__find(map, key, value) \
+	hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
+
+/*
+ * hashmap__for_each_entry - iterate over all entries in hashmap
+ * @map: hashmap to iterate
+ * @cur: struct hashmap_entry * used as a loop cursor
+ * @bkt: integer used as a bucket loop cursor
+ */
+#define hashmap__for_each_entry(map, cur, bkt)				    \
+	for (bkt = 0; bkt < (map)->cap; bkt++)				    \
+		for (cur = (map)->buckets[bkt]; cur; cur = cur->next)
+
+/*
+ * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
+ * against removals
+ * @map: hashmap to iterate
+ * @cur: struct hashmap_entry * used as a loop cursor
+ * @tmp: struct hashmap_entry * used as a temporary next cursor storage
+ * @bkt: integer used as a bucket loop cursor
+ */
+#define hashmap__for_each_entry_safe(map, cur, tmp, bkt)		    \
+	for (bkt = 0; bkt < (map)->cap; bkt++)				    \
+		for (cur = (map)->buckets[bkt];				    \
+		     cur && ({tmp = cur->next; true; });		    \
+		     cur = tmp)
+
+/*
+ * hashmap__for_each_key_entry - iterate over entries associated with given key
+ * @map: hashmap to iterate
+ * @cur: struct hashmap_entry * used as a loop cursor
+ * @key: key to iterate entries for
+ */
+#define hashmap__for_each_key_entry(map, cur, _key)			    \
+	for (cur = (map)->buckets					    \
+		     ? (map)->buckets[hash_bits((map)->hash_fn((_key), (map)->ctx), (map)->cap_bits)] \
+		     : NULL;						    \
+	     cur;							    \
+	     cur = cur->next)						    \
+		if ((map)->equal_fn(cur->key, (_key), (map)->ctx))
+
+#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key)		    \
+	for (cur = (map)->buckets					    \
+		     ? (map)->buckets[hash_bits((map)->hash_fn((_key), (map)->ctx), (map)->cap_bits)] \
+		     : NULL;						    \
+	     cur && ({ tmp = cur->next; true; });			    \
+	     cur = tmp)							    \
+		if ((map)->equal_fn(cur->key, (_key), (map)->ctx))
+
+#endif /* __LIBBPF_HASHMAP_H */
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
new file mode 100644
index 000000000..b749c0174
--- /dev/null
+++ b/tools/lib/bpf/libbpf.c
@@ -0,0 +1,15223 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * Common eBPF ELF object loading operations.
+ *
+ * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ * Copyright (C) 2017 Nicira, Inc.
+ * Copyright (C) 2019 Isovalent, Inc.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <libgen.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <string.h>
+#include <unistd.h>
+#include <endian.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <ctype.h>
+#include <asm/unistd.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <linux/limits.h>
+#include <linux/perf_event.h>
+#include <linux/bpf_perf_event.h>
+#include <linux/ring_buffer.h>
+#include <sys/epoll.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+#include <sys/utsname.h>
+#include <sys/resource.h>
+#include <libelf.h>
+#include <gelf.h>
+#include <zlib.h>
+
+#include "libbpf.h"
+#include "bpf.h"
+#include "btf.h"
+#include "libbpf_internal.h"
+#include "hashmap.h"
+#include "bpf_gen_internal.h"
+#include "zip.h"
+
+#ifndef BPF_FS_MAGIC
+#define BPF_FS_MAGIC		0xcafe4a11
+#endif
+
+#define MAX_EVENT_NAME_LEN	64
+
+#define BPF_FS_DEFAULT_PATH "/sys/fs/bpf"
+
+#define BPF_INSN_SZ (sizeof(struct bpf_insn))
+
+/* vsprintf() in __base_pr() uses nonliteral format string. It may break
+ * compilation if user enables corresponding warning. Disable it explicitly.
+ */
+#pragma GCC diagnostic ignored "-Wformat-nonliteral"
+
+#define __printf(a, b)	__attribute__((format(printf, a, b)))
+
+static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
+static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog);
+static int map_set_def_max_entries(struct bpf_map *map);
+
+static const char * const attach_type_name[] = {
+	[BPF_CGROUP_INET_INGRESS]	= "cgroup_inet_ingress",
+	[BPF_CGROUP_INET_EGRESS]	= "cgroup_inet_egress",
+	[BPF_CGROUP_INET_SOCK_CREATE]	= "cgroup_inet_sock_create",
+	[BPF_CGROUP_INET_SOCK_RELEASE]	= "cgroup_inet_sock_release",
+	[BPF_CGROUP_SOCK_OPS]		= "cgroup_sock_ops",
+	[BPF_CGROUP_DEVICE]		= "cgroup_device",
+	[BPF_CGROUP_INET4_BIND]		= "cgroup_inet4_bind",
+	[BPF_CGROUP_INET6_BIND]		= "cgroup_inet6_bind",
+	[BPF_CGROUP_INET4_CONNECT]	= "cgroup_inet4_connect",
+	[BPF_CGROUP_INET6_CONNECT]	= "cgroup_inet6_connect",
+	[BPF_CGROUP_UNIX_CONNECT]       = "cgroup_unix_connect",
+	[BPF_CGROUP_INET4_POST_BIND]	= "cgroup_inet4_post_bind",
+	[BPF_CGROUP_INET6_POST_BIND]	= "cgroup_inet6_post_bind",
+	[BPF_CGROUP_INET4_GETPEERNAME]	= "cgroup_inet4_getpeername",
+	[BPF_CGROUP_INET6_GETPEERNAME]	= "cgroup_inet6_getpeername",
+	[BPF_CGROUP_UNIX_GETPEERNAME]	= "cgroup_unix_getpeername",
+	[BPF_CGROUP_INET4_GETSOCKNAME]	= "cgroup_inet4_getsockname",
+	[BPF_CGROUP_INET6_GETSOCKNAME]	= "cgroup_inet6_getsockname",
+	[BPF_CGROUP_UNIX_GETSOCKNAME]	= "cgroup_unix_getsockname",
+	[BPF_CGROUP_UDP4_SENDMSG]	= "cgroup_udp4_sendmsg",
+	[BPF_CGROUP_UDP6_SENDMSG]	= "cgroup_udp6_sendmsg",
+	[BPF_CGROUP_UNIX_SENDMSG]	= "cgroup_unix_sendmsg",
+	[BPF_CGROUP_SYSCTL]		= "cgroup_sysctl",
+	[BPF_CGROUP_UDP4_RECVMSG]	= "cgroup_udp4_recvmsg",
+	[BPF_CGROUP_UDP6_RECVMSG]	= "cgroup_udp6_recvmsg",
+	[BPF_CGROUP_UNIX_RECVMSG]	= "cgroup_unix_recvmsg",
+	[BPF_CGROUP_GETSOCKOPT]		= "cgroup_getsockopt",
+	[BPF_CGROUP_SETSOCKOPT]		= "cgroup_setsockopt",
+	[BPF_SK_SKB_STREAM_PARSER]	= "sk_skb_stream_parser",
+	[BPF_SK_SKB_STREAM_VERDICT]	= "sk_skb_stream_verdict",
+	[BPF_SK_SKB_VERDICT]		= "sk_skb_verdict",
+	[BPF_SK_MSG_VERDICT]		= "sk_msg_verdict",
+	[BPF_LIRC_MODE2]		= "lirc_mode2",
+	[BPF_FLOW_DISSECTOR]		= "flow_dissector",
+	[BPF_TRACE_RAW_TP]		= "trace_raw_tp",
+	[BPF_TRACE_FENTRY]		= "trace_fentry",
+	[BPF_TRACE_FEXIT]		= "trace_fexit",
+	[BPF_MODIFY_RETURN]		= "modify_return",
+	[BPF_TRACE_FSESSION]		= "trace_fsession",
+	[BPF_LSM_MAC]			= "lsm_mac",
+	[BPF_LSM_CGROUP]		= "lsm_cgroup",
+	[BPF_SK_LOOKUP]			= "sk_lookup",
+	[BPF_TRACE_ITER]		= "trace_iter",
+	[BPF_XDP_DEVMAP]		= "xdp_devmap",
+	[BPF_XDP_CPUMAP]		= "xdp_cpumap",
+	[BPF_XDP]			= "xdp",
+	[BPF_SK_REUSEPORT_SELECT]	= "sk_reuseport_select",
+	[BPF_SK_REUSEPORT_SELECT_OR_MIGRATE]	= "sk_reuseport_select_or_migrate",
+	[BPF_PERF_EVENT]		= "perf_event",
+	[BPF_TRACE_KPROBE_MULTI]	= "trace_kprobe_multi",
+	[BPF_STRUCT_OPS]		= "struct_ops",
+	[BPF_NETFILTER]			= "netfilter",
+	[BPF_TCX_INGRESS]		= "tcx_ingress",
+	[BPF_TCX_EGRESS]		= "tcx_egress",
+	[BPF_TRACE_UPROBE_MULTI]	= "trace_uprobe_multi",
+	[BPF_NETKIT_PRIMARY]		= "netkit_primary",
+	[BPF_NETKIT_PEER]		= "netkit_peer",
+	[BPF_TRACE_KPROBE_SESSION]	= "trace_kprobe_session",
+	[BPF_TRACE_UPROBE_SESSION]	= "trace_uprobe_session",
+	[BPF_TRACE_FENTRY_MULTI]	= "trace_fentry_multi",
+	[BPF_TRACE_FEXIT_MULTI]		= "trace_fexit_multi",
+	[BPF_TRACE_FSESSION_MULTI]	= "trace_fsession_multi",
+};
+
+static const char * const link_type_name[] = {
+	[BPF_LINK_TYPE_UNSPEC]			= "unspec",
+	[BPF_LINK_TYPE_RAW_TRACEPOINT]		= "raw_tracepoint",
+	[BPF_LINK_TYPE_TRACING]			= "tracing",
+	[BPF_LINK_TYPE_CGROUP]			= "cgroup",
+	[BPF_LINK_TYPE_ITER]			= "iter",
+	[BPF_LINK_TYPE_NETNS]			= "netns",
+	[BPF_LINK_TYPE_XDP]			= "xdp",
+	[BPF_LINK_TYPE_PERF_EVENT]		= "perf_event",
+	[BPF_LINK_TYPE_KPROBE_MULTI]		= "kprobe_multi",
+	[BPF_LINK_TYPE_STRUCT_OPS]		= "struct_ops",
+	[BPF_LINK_TYPE_NETFILTER]		= "netfilter",
+	[BPF_LINK_TYPE_TCX]			= "tcx",
+	[BPF_LINK_TYPE_UPROBE_MULTI]		= "uprobe_multi",
+	[BPF_LINK_TYPE_NETKIT]			= "netkit",
+	[BPF_LINK_TYPE_SOCKMAP]			= "sockmap",
+	[BPF_LINK_TYPE_TRACING_MULTI]		= "tracing_multi",
+};
+
+static const char * const map_type_name[] = {
+	[BPF_MAP_TYPE_UNSPEC]			= "unspec",
+	[BPF_MAP_TYPE_HASH]			= "hash",
+	[BPF_MAP_TYPE_ARRAY]			= "array",
+	[BPF_MAP_TYPE_PROG_ARRAY]		= "prog_array",
+	[BPF_MAP_TYPE_PERF_EVENT_ARRAY]		= "perf_event_array",
+	[BPF_MAP_TYPE_PERCPU_HASH]		= "percpu_hash",
+	[BPF_MAP_TYPE_PERCPU_ARRAY]		= "percpu_array",
+	[BPF_MAP_TYPE_STACK_TRACE]		= "stack_trace",
+	[BPF_MAP_TYPE_CGROUP_ARRAY]		= "cgroup_array",
+	[BPF_MAP_TYPE_LRU_HASH]			= "lru_hash",
+	[BPF_MAP_TYPE_LRU_PERCPU_HASH]		= "lru_percpu_hash",
+	[BPF_MAP_TYPE_LPM_TRIE]			= "lpm_trie",
+	[BPF_MAP_TYPE_ARRAY_OF_MAPS]		= "array_of_maps",
+	[BPF_MAP_TYPE_HASH_OF_MAPS]		= "hash_of_maps",
+	[BPF_MAP_TYPE_DEVMAP]			= "devmap",
+	[BPF_MAP_TYPE_DEVMAP_HASH]		= "devmap_hash",
+	[BPF_MAP_TYPE_SOCKMAP]			= "sockmap",
+	[BPF_MAP_TYPE_CPUMAP]			= "cpumap",
+	[BPF_MAP_TYPE_XSKMAP]			= "xskmap",
+	[BPF_MAP_TYPE_SOCKHASH]			= "sockhash",
+	[BPF_MAP_TYPE_CGROUP_STORAGE]		= "cgroup_storage",
+	[BPF_MAP_TYPE_REUSEPORT_SOCKARRAY]	= "reuseport_sockarray",
+	[BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE]	= "percpu_cgroup_storage",
+	[BPF_MAP_TYPE_QUEUE]			= "queue",
+	[BPF_MAP_TYPE_STACK]			= "stack",
+	[BPF_MAP_TYPE_SK_STORAGE]		= "sk_storage",
+	[BPF_MAP_TYPE_STRUCT_OPS]		= "struct_ops",
+	[BPF_MAP_TYPE_RINGBUF]			= "ringbuf",
+	[BPF_MAP_TYPE_INODE_STORAGE]		= "inode_storage",
+	[BPF_MAP_TYPE_TASK_STORAGE]		= "task_storage",
+	[BPF_MAP_TYPE_BLOOM_FILTER]		= "bloom_filter",
+	[BPF_MAP_TYPE_USER_RINGBUF]             = "user_ringbuf",
+	[BPF_MAP_TYPE_CGRP_STORAGE]		= "cgrp_storage",
+	[BPF_MAP_TYPE_ARENA]			= "arena",
+	[BPF_MAP_TYPE_INSN_ARRAY]		= "insn_array",
+	[BPF_MAP_TYPE_RHASH]			= "rhash",
+};
+
+static const char * const prog_type_name[] = {
+	[BPF_PROG_TYPE_UNSPEC]			= "unspec",
+	[BPF_PROG_TYPE_SOCKET_FILTER]		= "socket_filter",
+	[BPF_PROG_TYPE_KPROBE]			= "kprobe",
+	[BPF_PROG_TYPE_SCHED_CLS]		= "sched_cls",
+	[BPF_PROG_TYPE_SCHED_ACT]		= "sched_act",
+	[BPF_PROG_TYPE_TRACEPOINT]		= "tracepoint",
+	[BPF_PROG_TYPE_XDP]			= "xdp",
+	[BPF_PROG_TYPE_PERF_EVENT]		= "perf_event",
+	[BPF_PROG_TYPE_CGROUP_SKB]		= "cgroup_skb",
+	[BPF_PROG_TYPE_CGROUP_SOCK]		= "cgroup_sock",
+	[BPF_PROG_TYPE_LWT_IN]			= "lwt_in",
+	[BPF_PROG_TYPE_LWT_OUT]			= "lwt_out",
+	[BPF_PROG_TYPE_LWT_XMIT]		= "lwt_xmit",
+	[BPF_PROG_TYPE_SOCK_OPS]		= "sock_ops",
+	[BPF_PROG_TYPE_SK_SKB]			= "sk_skb",
+	[BPF_PROG_TYPE_CGROUP_DEVICE]		= "cgroup_device",
+	[BPF_PROG_TYPE_SK_MSG]			= "sk_msg",
+	[BPF_PROG_TYPE_RAW_TRACEPOINT]		= "raw_tracepoint",
+	[BPF_PROG_TYPE_CGROUP_SOCK_ADDR]	= "cgroup_sock_addr",
+	[BPF_PROG_TYPE_LWT_SEG6LOCAL]		= "lwt_seg6local",
+	[BPF_PROG_TYPE_LIRC_MODE2]		= "lirc_mode2",
+	[BPF_PROG_TYPE_SK_REUSEPORT]		= "sk_reuseport",
+	[BPF_PROG_TYPE_FLOW_DISSECTOR]		= "flow_dissector",
+	[BPF_PROG_TYPE_CGROUP_SYSCTL]		= "cgroup_sysctl",
+	[BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE]	= "raw_tracepoint_writable",
+	[BPF_PROG_TYPE_CGROUP_SOCKOPT]		= "cgroup_sockopt",
+	[BPF_PROG_TYPE_TRACING]			= "tracing",
+	[BPF_PROG_TYPE_STRUCT_OPS]		= "struct_ops",
+	[BPF_PROG_TYPE_EXT]			= "ext",
+	[BPF_PROG_TYPE_LSM]			= "lsm",
+	[BPF_PROG_TYPE_SK_LOOKUP]		= "sk_lookup",
+	[BPF_PROG_TYPE_SYSCALL]			= "syscall",
+	[BPF_PROG_TYPE_NETFILTER]		= "netfilter",
+};
+
+static int __base_pr(enum libbpf_print_level level, const char *format,
+		     va_list args)
+{
+	const char *env_var = "LIBBPF_LOG_LEVEL";
+	static enum libbpf_print_level min_level = LIBBPF_INFO;
+	static bool initialized;
+
+	if (!initialized) {
+		char *verbosity;
+
+		initialized = true;
+		verbosity = getenv(env_var);
+		if (verbosity) {
+			if (strcasecmp(verbosity, "warn") == 0)
+				min_level = LIBBPF_WARN;
+			else if (strcasecmp(verbosity, "debug") == 0)
+				min_level = LIBBPF_DEBUG;
+			else if (strcasecmp(verbosity, "info") == 0)
+				min_level = LIBBPF_INFO;
+			else
+				fprintf(stderr, "libbpf: unrecognized '%s' envvar value: '%s', should be one of 'warn', 'debug', or 'info'.\n",
+					env_var, verbosity);
+		}
+	}
+
+	/* if too verbose, skip logging  */
+	if (level > min_level)
+		return 0;
+
+	return vfprintf(stderr, format, args);
+}
+
+static libbpf_print_fn_t __libbpf_pr = __base_pr;
+
+libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
+{
+	libbpf_print_fn_t old_print_fn;
+
+	old_print_fn = __atomic_exchange_n(&__libbpf_pr, fn, __ATOMIC_RELAXED);
+
+	return old_print_fn;
+}
+
+__printf(2, 3)
+void libbpf_print(enum libbpf_print_level level, const char *format, ...)
+{
+	va_list args;
+	int old_errno;
+	libbpf_print_fn_t print_fn;
+
+	print_fn = __atomic_load_n(&__libbpf_pr, __ATOMIC_RELAXED);
+	if (!print_fn)
+		return;
+
+	old_errno = errno;
+
+	va_start(args, format);
+	print_fn(level, format, args);
+	va_end(args);
+
+	errno = old_errno;
+}
+
+static void pr_perm_msg(int err)
+{
+	struct rlimit limit;
+	char buf[100];
+
+	if (err != -EPERM || geteuid() != 0)
+		return;
+
+	err = getrlimit(RLIMIT_MEMLOCK, &limit);
+	if (err)
+		return;
+
+	if (limit.rlim_cur == RLIM_INFINITY)
+		return;
+
+	if (limit.rlim_cur < 1024)
+		snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
+	else if (limit.rlim_cur < 1024*1024)
+		snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
+	else
+		snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024));
+
+	pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n",
+		buf);
+}
+
+/* Copied from tools/perf/util/util.h */
+#ifndef zfree
+# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
+#endif
+
+#ifndef zclose
+# define zclose(fd) ({			\
+	int ___err = 0;			\
+	if ((fd) >= 0)			\
+		___err = close((fd));	\
+	fd = -1;			\
+	___err; })
+#endif
+
+static inline __u64 ptr_to_u64(const void *ptr)
+{
+	return (__u64) (unsigned long) ptr;
+}
+
+int libbpf_set_strict_mode(enum libbpf_strict_mode mode)
+{
+	/* as of v1.0 libbpf_set_strict_mode() is a no-op */
+	return 0;
+}
+
+__u32 libbpf_major_version(void)
+{
+	return LIBBPF_MAJOR_VERSION;
+}
+
+__u32 libbpf_minor_version(void)
+{
+	return LIBBPF_MINOR_VERSION;
+}
+
+const char *libbpf_version_string(void)
+{
+#define __S(X) #X
+#define _S(X) __S(X)
+	return  "v" _S(LIBBPF_MAJOR_VERSION) "." _S(LIBBPF_MINOR_VERSION);
+#undef _S
+#undef __S
+}
+
+enum reloc_type {
+	RELO_LD64,
+	RELO_CALL,
+	RELO_DATA,
+	RELO_EXTERN_LD64,
+	RELO_EXTERN_CALL,
+	RELO_SUBPROG_ADDR,
+	RELO_CORE,
+	RELO_INSN_ARRAY,
+};
+
+struct reloc_desc {
+	enum reloc_type type;
+	int insn_idx;
+	union {
+		const struct bpf_core_relo *core_relo; /* used when type == RELO_CORE */
+		struct {
+			int map_idx;
+			unsigned int sym_off;
+			/*
+			 * The following two fields can be unionized, as the
+			 * ext_idx field is used for extern symbols, and the
+			 * sym_size is used for jump tables, which are never
+			 * extern
+			 */
+			union {
+				int ext_idx;
+				int sym_size;
+			};
+		};
+	};
+};
+
+/* stored as sec_def->cookie for all libbpf-supported SEC()s */
+enum sec_def_flags {
+	SEC_NONE = 0,
+	/* expected_attach_type is optional, if kernel doesn't support that */
+	SEC_EXP_ATTACH_OPT = 1,
+	/* legacy, only used by libbpf_get_type_names() and
+	 * libbpf_attach_type_by_name(), not used by libbpf itself at all.
+	 * This used to be associated with cgroup (and few other) BPF programs
+	 * that were attachable through BPF_PROG_ATTACH command. Pretty
+	 * meaningless nowadays, though.
+	 */
+	SEC_ATTACHABLE = 2,
+	SEC_ATTACHABLE_OPT = SEC_ATTACHABLE | SEC_EXP_ATTACH_OPT,
+	/* attachment target is specified through BTF ID in either kernel or
+	 * other BPF program's BTF object
+	 */
+	SEC_ATTACH_BTF = 4,
+	/* BPF program type allows sleeping/blocking in kernel */
+	SEC_SLEEPABLE = 8,
+	/* BPF program support non-linear XDP buffer */
+	SEC_XDP_FRAGS = 16,
+	/* Setup proper attach type for usdt probes. */
+	SEC_USDT = 32,
+};
+
+struct bpf_sec_def {
+	char *sec;
+	enum bpf_prog_type prog_type;
+	enum bpf_attach_type expected_attach_type;
+	long cookie;
+	int handler_id;
+
+	libbpf_prog_setup_fn_t prog_setup_fn;
+	libbpf_prog_prepare_load_fn_t prog_prepare_load_fn;
+	libbpf_prog_attach_fn_t prog_attach_fn;
+};
+
+struct bpf_light_subprog {
+	__u32 sec_insn_off;
+	__u32 sub_insn_off;
+};
+
+/*
+ * bpf_prog should be a better name but it has been used in
+ * linux/filter.h.
+ */
+struct bpf_program {
+	char *name;
+	char *sec_name;
+	size_t sec_idx;
+	const struct bpf_sec_def *sec_def;
+	/* this program's instruction offset (in number of instructions)
+	 * within its containing ELF section
+	 */
+	size_t sec_insn_off;
+	/* number of original instructions in ELF section belonging to this
+	 * program, not taking into account subprogram instructions possible
+	 * appended later during relocation
+	 */
+	size_t sec_insn_cnt;
+	/* Offset (in number of instructions) of the start of instruction
+	 * belonging to this BPF program  within its containing main BPF
+	 * program. For the entry-point (main) BPF program, this is always
+	 * zero. For a sub-program, this gets reset before each of main BPF
+	 * programs are processed and relocated and is used to determined
+	 * whether sub-program was already appended to the main program, and
+	 * if yes, at which instruction offset.
+	 */
+	size_t sub_insn_off;
+
+	/* instructions that belong to BPF program; insns[0] is located at
+	 * sec_insn_off instruction within its ELF section in ELF file, so
+	 * when mapping ELF file instruction index to the local instruction,
+	 * one needs to subtract sec_insn_off; and vice versa.
+	 */
+	struct bpf_insn *insns;
+	/* actual number of instruction in this BPF program's image; for
+	 * entry-point BPF programs this includes the size of main program
+	 * itself plus all the used sub-programs, appended at the end
+	 */
+	size_t insns_cnt;
+
+	struct reloc_desc *reloc_desc;
+	int nr_reloc;
+
+	/* BPF verifier log settings */
+	char *log_buf;
+	size_t log_size;
+	__u32 log_level;
+
+	struct bpf_object *obj;
+
+	int fd;
+	bool autoload;
+	bool autoattach;
+	bool sym_global;
+	bool mark_btf_static;
+	enum bpf_prog_type type;
+	enum bpf_attach_type expected_attach_type;
+	int exception_cb_idx;
+
+	int prog_ifindex;
+	__u32 attach_btf_obj_fd;
+	__u32 attach_btf_id;
+	__u32 attach_prog_fd;
+
+	void *func_info;
+	__u32 func_info_rec_size;
+	__u32 func_info_cnt;
+
+	void *line_info;
+	__u32 line_info_rec_size;
+	__u32 line_info_cnt;
+	__u32 prog_flags;
+	__u8  hash[SHA256_DIGEST_LENGTH];
+
+	struct bpf_light_subprog *subprogs;
+	__u32 subprog_cnt;
+};
+
+struct bpf_struct_ops {
+	struct bpf_program **progs;
+	__u32 *kern_func_off;
+	/* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
+	void *data;
+	/* e.g. struct bpf_struct_ops_tcp_congestion_ops in
+	 *      btf_vmlinux's format.
+	 * struct bpf_struct_ops_tcp_congestion_ops {
+	 *	[... some other kernel fields ...]
+	 *	struct tcp_congestion_ops data;
+	 * }
+	 * kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops)
+	 * bpf_map__init_kern_struct_ops() will populate the "kern_vdata"
+	 * from "data".
+	 */
+	void *kern_vdata;
+	__u32 type_id;
+};
+
+#define DATA_SEC ".data"
+#define PERCPU_SEC ".percpu"
+#define BSS_SEC ".bss"
+#define RODATA_SEC ".rodata"
+#define KCONFIG_SEC ".kconfig"
+#define KSYMS_SEC ".ksyms"
+#define STRUCT_OPS_SEC ".struct_ops"
+#define STRUCT_OPS_LINK_SEC ".struct_ops.link"
+#define ARENA_SEC ".addr_space.1"
+
+enum libbpf_map_type {
+	LIBBPF_MAP_UNSPEC,
+	LIBBPF_MAP_DATA,
+	LIBBPF_MAP_BSS,
+	LIBBPF_MAP_RODATA,
+	LIBBPF_MAP_KCONFIG,
+	LIBBPF_MAP_PERCPU,
+};
+
+struct bpf_map_def {
+	unsigned int type;
+	unsigned int key_size;
+	unsigned int value_size;
+	unsigned int max_entries;
+	unsigned int map_flags;
+};
+
+struct bpf_map {
+	struct bpf_object *obj;
+	char *name;
+	/* real_name is defined for special internal maps (.rodata*,
+	 * .data*, .bss, .kconfig) and preserves their original ELF section
+	 * name. This is important to be able to find corresponding BTF
+	 * DATASEC information.
+	 */
+	char *real_name;
+	int fd;
+	int sec_idx;
+	size_t sec_offset;
+	int map_ifindex;
+	int inner_map_fd;
+	struct bpf_map_def def;
+	__u32 numa_node;
+	__u32 btf_var_idx;
+	int mod_btf_fd;
+	__u32 btf_key_type_id;
+	__u32 btf_value_type_id;
+	__u32 btf_vmlinux_value_type_id;
+	enum libbpf_map_type libbpf_type;
+	void *mmaped;
+	struct bpf_struct_ops *st_ops;
+	struct bpf_map *inner_map;
+	void **init_slots;
+	int init_slots_sz;
+	char *pin_path;
+	bool pinned;
+	bool reused;
+	bool autocreate;
+	bool autoattach;
+	__u64 map_extra;
+	struct bpf_program *excl_prog;
+};
+
+enum extern_type {
+	EXT_UNKNOWN,
+	EXT_KCFG,
+	EXT_KSYM,
+};
+
+enum kcfg_type {
+	KCFG_UNKNOWN,
+	KCFG_CHAR,
+	KCFG_BOOL,
+	KCFG_INT,
+	KCFG_TRISTATE,
+	KCFG_CHAR_ARR,
+};
+
+struct extern_desc {
+	enum extern_type type;
+	int sym_idx;
+	int btf_id;
+	int sec_btf_id;
+	char *name;
+	char *essent_name;
+	bool is_set;
+	bool is_weak;
+	union {
+		struct {
+			enum kcfg_type type;
+			int sz;
+			int align;
+			int data_off;
+			bool is_signed;
+		} kcfg;
+		struct {
+			unsigned long long addr;
+
+			/* target btf_id of the corresponding kernel var. */
+			int kernel_btf_obj_fd;
+			int kernel_btf_id;
+
+			/* local btf_id of the ksym extern's type. */
+			__u32 type_id;
+			/* BTF fd index to be patched in for insn->off, this is
+			 * 0 for vmlinux BTF, index in obj->fd_array for module
+			 * BTF
+			 */
+			__s16 btf_fd_idx;
+		} ksym;
+	};
+};
+
+struct module_btf {
+	struct btf *btf;
+	char *name;
+	__u32 id;
+	int fd;
+	int fd_array_idx;
+};
+
+enum sec_type {
+	SEC_UNUSED = 0,
+	SEC_RELO,
+	SEC_BSS,
+	SEC_DATA,
+	SEC_RODATA,
+	SEC_ST_OPS,
+	SEC_PERCPU,
+};
+
+struct elf_sec_desc {
+	enum sec_type sec_type;
+	Elf64_Shdr *shdr;
+	Elf_Data *data;
+};
+
+struct elf_state {
+	int fd;
+	const void *obj_buf;
+	size_t obj_buf_sz;
+	Elf *elf;
+	Elf64_Ehdr *ehdr;
+	Elf_Data *symbols;
+	Elf_Data *arena_data;
+	size_t shstrndx; /* section index for section name strings */
+	size_t strtabidx;
+	struct elf_sec_desc *secs;
+	size_t sec_cnt;
+	int btf_maps_shndx;
+	__u32 btf_maps_sec_btf_id;
+	int text_shndx;
+	int symbols_shndx;
+	bool has_st_ops;
+	int arena_data_shndx;
+	int jumptables_data_shndx;
+};
+
+struct usdt_manager;
+
+enum bpf_object_state {
+	OBJ_OPEN,
+	OBJ_PREPARED,
+	OBJ_LOADED,
+};
+
+struct bpf_object {
+	char name[BPF_OBJ_NAME_LEN];
+	char license[64];
+	__u32 kern_version;
+
+	enum bpf_object_state state;
+	struct bpf_program *programs;
+	size_t nr_programs;
+	struct bpf_map *maps;
+	size_t nr_maps;
+	size_t maps_cap;
+
+	char *kconfig;
+	struct extern_desc *externs;
+	int nr_extern;
+	int kconfig_map_idx;
+
+	bool has_subcalls;
+	bool has_rodata;
+
+	struct bpf_gen *gen_loader;
+
+	/* Information when doing ELF related work. Only valid if efile.elf is not NULL */
+	struct elf_state efile;
+
+	unsigned char byteorder;
+
+	struct btf *btf;
+	struct btf_ext *btf_ext;
+
+	/* Parse and load BTF vmlinux if any of the programs in the object need
+	 * it at load time.
+	 */
+	struct btf *btf_vmlinux;
+	/* Path to the custom BTF to be used for BPF CO-RE relocations as an
+	 * override for vmlinux BTF.
+	 */
+	char *btf_custom_path;
+	/* vmlinux BTF override for CO-RE relocations */
+	struct btf *btf_vmlinux_override;
+	/* Lazily initialized kernel module BTFs */
+	struct module_btf *btf_modules;
+	bool btf_modules_loaded;
+	size_t btf_module_cnt;
+	size_t btf_module_cap;
+
+	/* optional log settings passed to BPF_BTF_LOAD and BPF_PROG_LOAD commands */
+	char *log_buf;
+	size_t log_size;
+	__u32 log_level;
+
+	int *fd_array;
+	size_t fd_array_cap;
+	size_t fd_array_cnt;
+
+	struct usdt_manager *usdt_man;
+
+	int arena_map_idx;
+	void *arena_data;
+	size_t arena_data_sz;
+	size_t arena_data_off;
+
+	void *jumptables_data;
+	size_t jumptables_data_sz;
+
+	struct {
+		struct bpf_program *prog;
+		unsigned int sym_off;
+		int fd;
+	} *jumptable_maps;
+	size_t jumptable_map_cnt;
+
+	struct kern_feature_cache *feat_cache;
+	char *token_path;
+	int token_fd;
+
+	char path[];
+};
+
+static const char *elf_sym_str(const struct bpf_object *obj, size_t off);
+static const char *elf_sec_str(const struct bpf_object *obj, size_t off);
+static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx);
+static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name);
+static Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn);
+static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn);
+static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn);
+static Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx);
+static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx);
+
+void bpf_program__unload(struct bpf_program *prog)
+{
+	if (!prog)
+		return;
+
+	zclose(prog->fd);
+
+	zfree(&prog->func_info);
+	zfree(&prog->line_info);
+	zfree(&prog->subprogs);
+}
+
+static void bpf_program__exit(struct bpf_program *prog)
+{
+	if (!prog)
+		return;
+
+	bpf_program__unload(prog);
+	zfree(&prog->name);
+	zfree(&prog->sec_name);
+	zfree(&prog->insns);
+	zfree(&prog->reloc_desc);
+
+	prog->nr_reloc = 0;
+	prog->insns_cnt = 0;
+	prog->sec_idx = -1;
+}
+
+static bool insn_is_subprog_call(const struct bpf_insn *insn)
+{
+	return BPF_CLASS(insn->code) == BPF_JMP &&
+	       BPF_OP(insn->code) == BPF_CALL &&
+	       BPF_SRC(insn->code) == BPF_K &&
+	       insn->src_reg == BPF_PSEUDO_CALL &&
+	       insn->dst_reg == 0 &&
+	       insn->off == 0;
+}
+
+static bool is_call_insn(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL);
+}
+
+static bool insn_is_pseudo_func(struct bpf_insn *insn)
+{
+	return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
+}
+
+static int
+bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog,
+		      const char *name, size_t sec_idx, const char *sec_name,
+		      size_t sec_off, void *insn_data, size_t insn_data_sz)
+{
+	if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) {
+		pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n",
+			sec_name, name, sec_off, insn_data_sz);
+		return -EINVAL;
+	}
+
+	memset(prog, 0, sizeof(*prog));
+	prog->obj = obj;
+
+	prog->sec_idx = sec_idx;
+	prog->sec_insn_off = sec_off / BPF_INSN_SZ;
+	prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ;
+	/* insns_cnt can later be increased by appending used subprograms */
+	prog->insns_cnt = prog->sec_insn_cnt;
+
+	prog->type = BPF_PROG_TYPE_UNSPEC;
+	prog->fd = -1;
+	prog->exception_cb_idx = -1;
+
+	/* libbpf's convention for SEC("?abc...") is that it's just like
+	 * SEC("abc...") but the corresponding bpf_program starts out with
+	 * autoload set to false.
+	 */
+	if (sec_name[0] == '?') {
+		prog->autoload = false;
+		/* from now on forget there was ? in section name */
+		sec_name++;
+	} else {
+		prog->autoload = true;
+	}
+
+	prog->autoattach = true;
+
+	/* inherit object's log_level */
+	prog->log_level = obj->log_level;
+
+	prog->sec_name = strdup(sec_name);
+	if (!prog->sec_name)
+		goto errout;
+
+	prog->name = strdup(name);
+	if (!prog->name)
+		goto errout;
+
+	prog->insns = malloc(insn_data_sz);
+	if (!prog->insns)
+		goto errout;
+	memcpy(prog->insns, insn_data, insn_data_sz);
+
+	return 0;
+errout:
+	pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name);
+	bpf_program__exit(prog);
+	return -ENOMEM;
+}
+
+static int
+bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
+			 const char *sec_name, int sec_idx)
+{
+	Elf_Data *symbols = obj->efile.symbols;
+	struct bpf_program *prog, *progs;
+	void *data = sec_data->d_buf;
+	size_t sec_sz = sec_data->d_size, sec_off, prog_sz, nr_syms;
+	int nr_progs, err, i;
+	const char *name;
+	Elf64_Sym *sym;
+
+	progs = obj->programs;
+	nr_progs = obj->nr_programs;
+	nr_syms = symbols->d_size / sizeof(Elf64_Sym);
+
+	for (i = 0; i < nr_syms; i++) {
+		sym = elf_sym_by_idx(obj, i);
+
+		if (sym->st_shndx != sec_idx)
+			continue;
+		if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC)
+			continue;
+
+		prog_sz = sym->st_size;
+		sec_off = sym->st_value;
+
+		name = elf_sym_str(obj, sym->st_name);
+		if (!name) {
+			pr_warn("sec '%s': failed to get symbol name for offset %zu\n",
+				sec_name, sec_off);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		if (sec_off + prog_sz > sec_sz || sec_off + prog_sz < sec_off) {
+			pr_warn("sec '%s': program at offset %zu crosses section boundary\n",
+				sec_name, sec_off);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		if (sec_idx != obj->efile.text_shndx && ELF64_ST_BIND(sym->st_info) == STB_LOCAL) {
+			pr_warn("sec '%s': program '%s' is static and not supported\n", sec_name, name);
+			return -ENOTSUP;
+		}
+
+		pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n",
+			 sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz);
+
+		progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(*progs));
+		if (!progs) {
+			/*
+			 * In this case the original obj->programs
+			 * is still valid, so don't need special treat for
+			 * bpf_close_object().
+			 */
+			pr_warn("sec '%s': failed to alloc memory for new program '%s'\n",
+				sec_name, name);
+			return -ENOMEM;
+		}
+		obj->programs = progs;
+
+		prog = &progs[nr_progs];
+
+		err = bpf_object__init_prog(obj, prog, name, sec_idx, sec_name,
+					    sec_off, data + sec_off, prog_sz);
+		if (err)
+			return err;
+
+		if (ELF64_ST_BIND(sym->st_info) != STB_LOCAL)
+			prog->sym_global = true;
+
+		/* if function is a global/weak symbol, but has restricted
+		 * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF FUNC
+		 * as static to enable more permissive BPF verification mode
+		 * with more outside context available to BPF verifier
+		 */
+		if (prog->sym_global && (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN
+		    || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL))
+			prog->mark_btf_static = true;
+
+		nr_progs++;
+		obj->nr_programs = nr_progs;
+	}
+
+	return 0;
+}
+
+static void bpf_object_bswap_progs(struct bpf_object *obj)
+{
+	struct bpf_program *prog = obj->programs;
+	struct bpf_insn *insn;
+	int p, i;
+
+	for (p = 0; p < obj->nr_programs; p++, prog++) {
+		insn = prog->insns;
+		for (i = 0; i < prog->insns_cnt; i++, insn++)
+			bpf_insn_bswap(insn);
+	}
+	pr_debug("converted %zu BPF programs to native byte order\n", obj->nr_programs);
+}
+
+static const struct btf_member *
+find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
+{
+	struct btf_member *m;
+	int i;
+
+	for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
+		if (btf_member_bit_offset(t, i) == bit_offset)
+			return m;
+	}
+
+	return NULL;
+}
+
+static const struct btf_member *
+find_member_by_name(const struct btf *btf, const struct btf_type *t,
+		    const char *name)
+{
+	struct btf_member *m;
+	int i;
+
+	for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
+		if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
+			return m;
+	}
+
+	return NULL;
+}
+
+static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name,
+			    __u16 kind, struct btf **res_btf,
+			    struct module_btf **res_mod_btf);
+
+#define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
+static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
+				   const char *name, __u32 kind);
+
+static int
+find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw,
+			   struct module_btf **mod_btf,
+			   const struct btf_type **type, __u32 *type_id,
+			   const struct btf_type **vtype, __u32 *vtype_id,
+			   const struct btf_member **data_member)
+{
+	const struct btf_type *kern_type, *kern_vtype;
+	const struct btf_member *kern_data_member;
+	struct btf *btf = NULL;
+	__s32 kern_vtype_id, kern_type_id;
+	char tname[192], stname[256];
+	__u32 i;
+
+	snprintf(tname, sizeof(tname), "%.*s",
+		 (int)bpf_core_essential_name_len(tname_raw), tname_raw);
+
+	snprintf(stname, sizeof(stname), "%s%s", STRUCT_OPS_VALUE_PREFIX, tname);
+
+	/* Look for the corresponding "map_value" type that will be used
+	 * in map_update(BPF_MAP_TYPE_STRUCT_OPS) first, figure out the btf
+	 * and the mod_btf.
+	 * For example, find "struct bpf_struct_ops_tcp_congestion_ops".
+	 */
+	kern_vtype_id = find_ksym_btf_id(obj, stname, BTF_KIND_STRUCT, &btf, mod_btf);
+	if (kern_vtype_id < 0) {
+		pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", stname);
+		return kern_vtype_id;
+	}
+	kern_vtype = btf__type_by_id(btf, kern_vtype_id);
+
+	kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
+	if (kern_type_id < 0) {
+		pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", tname);
+		return kern_type_id;
+	}
+	kern_type = btf__type_by_id(btf, kern_type_id);
+
+	/* Find "struct tcp_congestion_ops" from
+	 * struct bpf_struct_ops_tcp_congestion_ops {
+	 *	[ ... ]
+	 *	struct tcp_congestion_ops data;
+	 * }
+	 */
+	kern_data_member = btf_members(kern_vtype);
+	for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) {
+		if (kern_data_member->type == kern_type_id)
+			break;
+	}
+	if (i == btf_vlen(kern_vtype)) {
+		pr_warn("struct_ops init_kern: struct %s data is not found in struct %s\n",
+			tname, stname);
+		return -EINVAL;
+	}
+
+	*type = kern_type;
+	*type_id = kern_type_id;
+	*vtype = kern_vtype;
+	*vtype_id = kern_vtype_id;
+	*data_member = kern_data_member;
+
+	return 0;
+}
+
+static bool bpf_map__is_struct_ops(const struct bpf_map *map)
+{
+	return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
+}
+
+static bool is_valid_st_ops_program(struct bpf_object *obj,
+				    const struct bpf_program *prog)
+{
+	int i;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		if (&obj->programs[i] == prog)
+			return prog->type == BPF_PROG_TYPE_STRUCT_OPS;
+	}
+
+	return false;
+}
+
+/* For each struct_ops program P, referenced from some struct_ops map M,
+ * enable P.autoload if there are Ms for which M.autocreate is true,
+ * disable P.autoload if for all Ms M.autocreate is false.
+ * Don't change P.autoload for programs that are not referenced from any maps.
+ */
+static int bpf_object_adjust_struct_ops_autoload(struct bpf_object *obj)
+{
+	struct bpf_program *prog, *slot_prog;
+	struct bpf_map *map;
+	int i, j, k, vlen;
+
+	for (i = 0; i < obj->nr_programs; ++i) {
+		int should_load = false;
+		int use_cnt = 0;
+
+		prog = &obj->programs[i];
+		if (prog->type != BPF_PROG_TYPE_STRUCT_OPS)
+			continue;
+
+		for (j = 0; j < obj->nr_maps; ++j) {
+			const struct btf_type *type;
+
+			map = &obj->maps[j];
+			if (!bpf_map__is_struct_ops(map))
+				continue;
+
+			type = btf__type_by_id(obj->btf, map->st_ops->type_id);
+			vlen = btf_vlen(type);
+			for (k = 0; k < vlen; ++k) {
+				slot_prog = map->st_ops->progs[k];
+				if (prog != slot_prog)
+					continue;
+
+				use_cnt++;
+				if (map->autocreate)
+					should_load = true;
+			}
+		}
+		if (use_cnt)
+			prog->autoload = should_load;
+	}
+
+	return 0;
+}
+
+/* Init the map's fields that depend on kern_btf */
+static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
+{
+	const struct btf_member *member, *kern_member, *kern_data_member;
+	const struct btf_type *type, *kern_type, *kern_vtype;
+	__u32 i, kern_type_id, kern_vtype_id, kern_data_off;
+	struct bpf_object *obj = map->obj;
+	const struct btf *btf = obj->btf;
+	struct bpf_struct_ops *st_ops;
+	const struct btf *kern_btf;
+	struct module_btf *mod_btf = NULL;
+	void *data, *kern_data;
+	const char *tname;
+	int err;
+
+	st_ops = map->st_ops;
+	type = btf__type_by_id(btf, st_ops->type_id);
+	tname = btf__name_by_offset(btf, type->name_off);
+	err = find_struct_ops_kern_types(obj, tname, &mod_btf,
+					 &kern_type, &kern_type_id,
+					 &kern_vtype, &kern_vtype_id,
+					 &kern_data_member);
+	if (err)
+		return err;
+
+	kern_btf = mod_btf ? mod_btf->btf : obj->btf_vmlinux;
+
+	pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
+		 map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
+
+	map->mod_btf_fd = mod_btf ? mod_btf->fd : -1;
+	map->def.value_size = kern_vtype->size;
+	map->btf_vmlinux_value_type_id = kern_vtype_id;
+
+	st_ops->kern_vdata = calloc(1, kern_vtype->size);
+	if (!st_ops->kern_vdata)
+		return -ENOMEM;
+
+	data = st_ops->data;
+	kern_data_off = kern_data_member->offset / 8;
+	kern_data = st_ops->kern_vdata + kern_data_off;
+
+	member = btf_members(type);
+	for (i = 0; i < btf_vlen(type); i++, member++) {
+		const struct btf_type *mtype, *kern_mtype;
+		__u32 mtype_id, kern_mtype_id;
+		void *mdata, *kern_mdata;
+		struct bpf_program *prog;
+		__s64 msize, kern_msize;
+		__u32 moff, kern_moff;
+		__u32 kern_member_idx;
+		const char *mname;
+
+		mname = btf__name_by_offset(btf, member->name_off);
+		moff = member->offset / 8;
+		mdata = data + moff;
+		msize = btf__resolve_size(btf, member->type);
+		if (msize < 0) {
+			pr_warn("struct_ops init_kern %s: failed to resolve the size of member %s\n",
+				map->name, mname);
+			return msize;
+		}
+
+		kern_member = find_member_by_name(kern_btf, kern_type, mname);
+		if (!kern_member) {
+			if (!libbpf_is_mem_zeroed(mdata, msize)) {
+				pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
+					map->name, mname);
+				return -ENOTSUP;
+			}
+
+			if (st_ops->progs[i]) {
+				/* If we had declaratively set struct_ops callback, we need to
+				 * force its autoload to false, because it doesn't have
+				 * a chance of succeeding from POV of the current struct_ops map.
+				 * If this program is still referenced somewhere else, though,
+				 * then bpf_object_adjust_struct_ops_autoload() will update its
+				 * autoload accordingly.
+				 */
+				st_ops->progs[i]->autoload = false;
+				st_ops->progs[i] = NULL;
+			}
+
+			/* Skip all-zero/NULL fields if they are not present in the kernel BTF */
+			pr_info("struct_ops %s: member %s not found in kernel, skipping it as it's set to zero\n",
+				map->name, mname);
+			continue;
+		}
+
+		kern_member_idx = kern_member - btf_members(kern_type);
+		if (btf_member_bitfield_size(type, i) ||
+		    btf_member_bitfield_size(kern_type, kern_member_idx)) {
+			pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n",
+				map->name, mname);
+			return -ENOTSUP;
+		}
+
+		kern_moff = kern_member->offset / 8;
+		kern_mdata = kern_data + kern_moff;
+
+		mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
+		kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type,
+						    &kern_mtype_id);
+		if (BTF_INFO_KIND(mtype->info) !=
+		    BTF_INFO_KIND(kern_mtype->info)) {
+			pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n",
+				map->name, mname, BTF_INFO_KIND(mtype->info),
+				BTF_INFO_KIND(kern_mtype->info));
+			return -ENOTSUP;
+		}
+
+		if (btf_is_ptr(mtype)) {
+			prog = *(void **)mdata;
+			/* just like for !kern_member case above, reset declaratively
+			 * set (at compile time) program's autload to false,
+			 * if user replaced it with another program or NULL
+			 */
+			if (st_ops->progs[i] && st_ops->progs[i] != prog)
+				st_ops->progs[i]->autoload = false;
+
+			/* Update the value from the shadow type */
+			st_ops->progs[i] = prog;
+			if (!prog)
+				continue;
+
+			if (!is_valid_st_ops_program(obj, prog)) {
+				pr_warn("struct_ops init_kern %s: member %s is not a struct_ops program\n",
+					map->name, mname);
+				return -ENOTSUP;
+			}
+
+			kern_mtype = skip_mods_and_typedefs(kern_btf,
+							    kern_mtype->type,
+							    &kern_mtype_id);
+
+			/* mtype->type must be a func_proto which was
+			 * guaranteed in bpf_object__collect_st_ops_relos(),
+			 * so only check kern_mtype for func_proto here.
+			 */
+			if (!btf_is_func_proto(kern_mtype)) {
+				pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n",
+					map->name, mname);
+				return -ENOTSUP;
+			}
+
+			if (mod_btf)
+				prog->attach_btf_obj_fd = mod_btf->fd;
+
+			/* if we haven't yet processed this BPF program, record proper
+			 * attach_btf_id and member_idx
+			 */
+			if (!prog->attach_btf_id) {
+				prog->attach_btf_id = kern_type_id;
+				prog->expected_attach_type = kern_member_idx;
+			}
+
+			/* struct_ops BPF prog can be re-used between multiple
+			 * .struct_ops & .struct_ops.link as long as it's the
+			 * same struct_ops struct definition and the same
+			 * function pointer field
+			 */
+			if (prog->attach_btf_id != kern_type_id) {
+				pr_warn("struct_ops init_kern %s func ptr %s: invalid reuse of prog %s in sec %s with type %u: attach_btf_id %u != kern_type_id %u\n",
+					map->name, mname, prog->name, prog->sec_name, prog->type,
+					prog->attach_btf_id, kern_type_id);
+				return -EINVAL;
+			}
+			if (prog->expected_attach_type != kern_member_idx) {
+				pr_warn("struct_ops init_kern %s func ptr %s: invalid reuse of prog %s in sec %s with type %u: expected_attach_type %u != kern_member_idx %u\n",
+					map->name, mname, prog->name, prog->sec_name, prog->type,
+					prog->expected_attach_type, kern_member_idx);
+				return -EINVAL;
+			}
+
+			st_ops->kern_func_off[i] = kern_data_off + kern_moff;
+
+			pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
+				 map->name, mname, prog->name, moff,
+				 kern_moff);
+
+			continue;
+		}
+
+		kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
+		if (kern_msize < 0 || msize != kern_msize) {
+			pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
+				map->name, mname, (ssize_t)msize,
+				(ssize_t)kern_msize);
+			return -ENOTSUP;
+		}
+
+		pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
+			 map->name, mname, (unsigned int)msize,
+			 moff, kern_moff);
+		memcpy(kern_mdata, mdata, msize);
+	}
+
+	return 0;
+}
+
+static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
+{
+	struct bpf_map *map;
+	size_t i;
+	int err;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		map = &obj->maps[i];
+
+		if (!bpf_map__is_struct_ops(map))
+			continue;
+
+		if (!map->autocreate)
+			continue;
+
+		err = bpf_map__init_kern_struct_ops(map);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name,
+				int shndx, Elf_Data *data)
+{
+	const struct btf_type *type, *datasec;
+	const struct btf_var_secinfo *vsi;
+	struct bpf_struct_ops *st_ops;
+	const char *tname, *var_name;
+	__s32 type_id, datasec_id;
+	const struct btf *btf;
+	struct bpf_map *map;
+	__u32 i;
+
+	if (shndx == -1)
+		return 0;
+
+	btf = obj->btf;
+	datasec_id = btf__find_by_name_kind(btf, sec_name,
+					    BTF_KIND_DATASEC);
+	if (datasec_id < 0) {
+		pr_warn("struct_ops init: DATASEC %s not found\n",
+			sec_name);
+		return -EINVAL;
+	}
+
+	datasec = btf__type_by_id(btf, datasec_id);
+	vsi = btf_var_secinfos(datasec);
+	for (i = 0; i < btf_vlen(datasec); i++, vsi++) {
+		type = btf__type_by_id(obj->btf, vsi->type);
+		var_name = btf__name_by_offset(obj->btf, type->name_off);
+
+		type_id = btf__resolve_type(obj->btf, vsi->type);
+		if (type_id < 0) {
+			pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
+				vsi->type, sec_name);
+			return -EINVAL;
+		}
+
+		type = btf__type_by_id(obj->btf, type_id);
+		tname = btf__name_by_offset(obj->btf, type->name_off);
+		if (!tname[0]) {
+			pr_warn("struct_ops init: anonymous type is not supported\n");
+			return -ENOTSUP;
+		}
+		if (!btf_is_struct(type)) {
+			pr_warn("struct_ops init: %s is not a struct\n", tname);
+			return -EINVAL;
+		}
+
+		map = bpf_object__add_map(obj);
+		if (IS_ERR(map))
+			return PTR_ERR(map);
+
+		map->sec_idx = shndx;
+		map->sec_offset = vsi->offset;
+		map->name = strdup(var_name);
+		if (!map->name)
+			return -ENOMEM;
+		map->btf_value_type_id = type_id;
+
+		/* Follow same convention as for programs autoload:
+		 * SEC("?.struct_ops") means map is not created by default.
+		 */
+		if (sec_name[0] == '?') {
+			map->autocreate = false;
+			/* from now on forget there was ? in section name */
+			sec_name++;
+		}
+
+		map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
+		map->def.key_size = sizeof(int);
+		map->def.value_size = type->size;
+		map->def.max_entries = 1;
+		map->def.map_flags = strcmp(sec_name, STRUCT_OPS_LINK_SEC) == 0 ? BPF_F_LINK : 0;
+		map->autoattach = true;
+
+		map->st_ops = calloc(1, sizeof(*map->st_ops));
+		if (!map->st_ops)
+			return -ENOMEM;
+		st_ops = map->st_ops;
+		st_ops->data = malloc(type->size);
+		st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
+		st_ops->kern_func_off = malloc(btf_vlen(type) *
+					       sizeof(*st_ops->kern_func_off));
+		if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
+			return -ENOMEM;
+
+		if (vsi->offset + type->size > data->d_size) {
+			pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n",
+				var_name, sec_name);
+			return -EINVAL;
+		}
+
+		memcpy(st_ops->data,
+		       data->d_buf + vsi->offset,
+		       type->size);
+		st_ops->type_id = type_id;
+
+		pr_debug("struct_ops init: struct %s(type_id=%d) %s found at offset %u\n",
+			 tname, type_id, var_name, vsi->offset);
+	}
+
+	return 0;
+}
+
+static int bpf_object_init_struct_ops(struct bpf_object *obj)
+{
+	const char *sec_name;
+	int sec_idx, err;
+
+	for (sec_idx = 0; sec_idx < obj->efile.sec_cnt; ++sec_idx) {
+		struct elf_sec_desc *desc = &obj->efile.secs[sec_idx];
+
+		if (desc->sec_type != SEC_ST_OPS)
+			continue;
+
+		sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx));
+		if (!sec_name)
+			return -LIBBPF_ERRNO__FORMAT;
+
+		err = init_struct_ops_maps(obj, sec_name, sec_idx, desc->data);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static struct bpf_object *bpf_object__new(const char *path,
+					  const void *obj_buf,
+					  size_t obj_buf_sz,
+					  const char *obj_name)
+{
+	struct bpf_object *obj;
+	char *end;
+
+	obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
+	if (!obj) {
+		pr_warn("alloc memory failed for %s\n", path);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	strcpy(obj->path, path);
+	if (obj_name) {
+		libbpf_strlcpy(obj->name, obj_name, sizeof(obj->name));
+	} else {
+		/* Using basename() GNU version which doesn't modify arg. */
+		libbpf_strlcpy(obj->name, basename((void *)path), sizeof(obj->name));
+		end = strchr(obj->name, '.');
+		if (end)
+			*end = 0;
+	}
+
+	obj->efile.fd = -1;
+	/*
+	 * Caller of this function should also call
+	 * bpf_object__elf_finish() after data collection to return
+	 * obj_buf to user. If not, we should duplicate the buffer to
+	 * avoid user freeing them before elf finish.
+	 */
+	obj->efile.obj_buf = obj_buf;
+	obj->efile.obj_buf_sz = obj_buf_sz;
+	obj->efile.btf_maps_shndx = -1;
+	obj->kconfig_map_idx = -1;
+	obj->arena_map_idx = -1;
+
+	obj->kern_version = get_kernel_version();
+	obj->state  = OBJ_OPEN;
+
+	return obj;
+}
+
+static void bpf_object__elf_finish(struct bpf_object *obj)
+{
+	if (!obj->efile.elf)
+		return;
+
+	elf_end(obj->efile.elf);
+	obj->efile.elf = NULL;
+	obj->efile.ehdr = NULL;
+	obj->efile.symbols = NULL;
+	obj->efile.arena_data = NULL;
+
+	zfree(&obj->efile.secs);
+	obj->efile.sec_cnt = 0;
+	zclose(obj->efile.fd);
+	obj->efile.obj_buf = NULL;
+	obj->efile.obj_buf_sz = 0;
+}
+
+static int bpf_object__elf_init(struct bpf_object *obj)
+{
+	Elf64_Ehdr *ehdr;
+	int err = 0;
+	Elf *elf;
+
+	if (obj->efile.elf) {
+		pr_warn("elf: init internal error\n");
+		return -LIBBPF_ERRNO__LIBELF;
+	}
+
+	if (obj->efile.obj_buf_sz > 0) {
+		/* obj_buf should have been validated by bpf_object__open_mem(). */
+		elf = elf_memory((char *)obj->efile.obj_buf, obj->efile.obj_buf_sz);
+	} else {
+		obj->efile.fd = open(obj->path, O_RDONLY | O_CLOEXEC);
+		if (obj->efile.fd < 0) {
+			err = -errno;
+			pr_warn("elf: failed to open %s: %s\n", obj->path, errstr(err));
+			return err;
+		}
+
+		elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL);
+	}
+
+	if (!elf) {
+		pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1));
+		err = -LIBBPF_ERRNO__LIBELF;
+		goto errout;
+	}
+
+	obj->efile.elf = elf;
+
+	if (elf_kind(elf) != ELF_K_ELF) {
+		err = -LIBBPF_ERRNO__FORMAT;
+		pr_warn("elf: '%s' is not a proper ELF object\n", obj->path);
+		goto errout;
+	}
+
+	if (gelf_getclass(elf) != ELFCLASS64) {
+		err = -LIBBPF_ERRNO__FORMAT;
+		pr_warn("elf: '%s' is not a 64-bit ELF object\n", obj->path);
+		goto errout;
+	}
+
+	obj->efile.ehdr = ehdr = elf64_getehdr(elf);
+	if (!obj->efile.ehdr) {
+		pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1));
+		err = -LIBBPF_ERRNO__FORMAT;
+		goto errout;
+	}
+
+	/* Validate ELF object endianness... */
+	if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
+	    ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
+		err = -LIBBPF_ERRNO__ENDIAN;
+		pr_warn("elf: '%s' has unknown byte order\n", obj->path);
+		goto errout;
+	}
+	/* and save after bpf_object_open() frees ELF data */
+	obj->byteorder = ehdr->e_ident[EI_DATA];
+
+	if (elf_getshdrstrndx(elf, &obj->efile.shstrndx)) {
+		pr_warn("elf: failed to get section names section index for %s: %s\n",
+			obj->path, elf_errmsg(-1));
+		err = -LIBBPF_ERRNO__FORMAT;
+		goto errout;
+	}
+
+	/* ELF is corrupted/truncated, avoid calling elf_strptr. */
+	if (!elf_rawdata(elf_getscn(elf, obj->efile.shstrndx), NULL)) {
+		pr_warn("elf: failed to get section names strings from %s: %s\n",
+			obj->path, elf_errmsg(-1));
+		err = -LIBBPF_ERRNO__FORMAT;
+		goto errout;
+	}
+
+	/* Old LLVM set e_machine to EM_NONE */
+	if (ehdr->e_type != ET_REL || (ehdr->e_machine && ehdr->e_machine != EM_BPF)) {
+		pr_warn("elf: %s is not a valid eBPF object file\n", obj->path);
+		err = -LIBBPF_ERRNO__FORMAT;
+		goto errout;
+	}
+
+	return 0;
+errout:
+	bpf_object__elf_finish(obj);
+	return err;
+}
+
+static bool is_native_endianness(struct bpf_object *obj)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	return obj->byteorder == ELFDATA2LSB;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	return obj->byteorder == ELFDATA2MSB;
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+}
+
+static int
+bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
+{
+	if (!data) {
+		pr_warn("invalid license section in %s\n", obj->path);
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+	/* libbpf_strlcpy() only copies first N - 1 bytes, so size + 1 won't
+	 * go over allowed ELF data section buffer
+	 */
+	libbpf_strlcpy(obj->license, data, min(size + 1, sizeof(obj->license)));
+	pr_debug("license of %s is %s\n", obj->path, obj->license);
+	return 0;
+}
+
+static int
+bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
+{
+	__u32 kver;
+
+	if (!data || size != sizeof(kver)) {
+		pr_warn("invalid kver section in %s\n", obj->path);
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+	memcpy(&kver, data, sizeof(kver));
+	obj->kern_version = kver;
+	pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
+	return 0;
+}
+
+static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
+{
+	if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
+	    type == BPF_MAP_TYPE_HASH_OF_MAPS)
+		return true;
+	return false;
+}
+
+static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size)
+{
+	Elf_Data *data;
+	Elf_Scn *scn;
+
+	if (!name)
+		return -EINVAL;
+
+	scn = elf_sec_by_name(obj, name);
+	data = elf_sec_data(obj, scn);
+	if (data) {
+		*size = data->d_size;
+		return 0; /* found it */
+	}
+
+	return -ENOENT;
+}
+
+static Elf64_Sym *find_elf_var_sym(const struct bpf_object *obj, const char *name)
+{
+	Elf_Data *symbols = obj->efile.symbols;
+	const char *sname;
+	size_t si;
+
+	for (si = 0; si < symbols->d_size / sizeof(Elf64_Sym); si++) {
+		Elf64_Sym *sym = elf_sym_by_idx(obj, si);
+
+		if (ELF64_ST_TYPE(sym->st_info) != STT_OBJECT)
+			continue;
+
+		if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL &&
+		    ELF64_ST_BIND(sym->st_info) != STB_WEAK)
+			continue;
+
+		sname = elf_sym_str(obj, sym->st_name);
+		if (!sname) {
+			pr_warn("failed to get sym name string for var %s\n", name);
+			return ERR_PTR(-EIO);
+		}
+		if (strcmp(name, sname) == 0)
+			return sym;
+	}
+
+	return ERR_PTR(-ENOENT);
+}
+
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 0x0001U
+#endif
+#ifndef MFD_NOEXEC_SEAL
+#define MFD_NOEXEC_SEAL 0x0008U
+#endif
+
+static int create_placeholder_fd(void)
+{
+	unsigned int flags = MFD_CLOEXEC | MFD_NOEXEC_SEAL;
+	const char *name = "libbpf-placeholder-fd";
+	int fd;
+
+	fd = ensure_good_fd(sys_memfd_create(name, flags));
+	if (fd >= 0)
+		return fd;
+	else if (errno != EINVAL)
+		return -errno;
+
+	/* Possibly running on kernel without MFD_NOEXEC_SEAL */
+	fd = ensure_good_fd(sys_memfd_create(name, flags & ~MFD_NOEXEC_SEAL));
+	if (fd < 0)
+		return -errno;
+	return fd;
+}
+
+static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
+{
+	struct bpf_map *map;
+	int err;
+
+	err = libbpf_ensure_mem((void **)&obj->maps, &obj->maps_cap,
+				sizeof(*obj->maps), obj->nr_maps + 1);
+	if (err)
+		return ERR_PTR(err);
+
+	map = &obj->maps[obj->nr_maps++];
+	map->obj = obj;
+	/* Preallocate map FD without actually creating BPF map just yet.
+	 * These map FD "placeholders" will be reused later without changing
+	 * FD value when map is actually created in the kernel.
+	 *
+	 * This is useful to be able to perform BPF program relocations
+	 * without having to create BPF maps before that step. This allows us
+	 * to finalize and load BTF very late in BPF object's loading phase,
+	 * right before BPF maps have to be created and BPF programs have to
+	 * be loaded. By having these map FD placeholders we can perform all
+	 * the sanitizations, relocations, and any other adjustments before we
+	 * start creating actual BPF kernel objects (BTF, maps, progs).
+	 */
+	map->fd = create_placeholder_fd();
+	if (map->fd < 0)
+		return ERR_PTR(map->fd);
+	map->inner_map_fd = -1;
+	map->autocreate = true;
+
+	return map;
+}
+
+static size_t array_map_mmap_sz(unsigned int value_sz, unsigned int max_entries)
+{
+	const long page_sz = sysconf(_SC_PAGE_SIZE);
+	size_t map_sz;
+
+	map_sz = (size_t)roundup(value_sz, 8) * max_entries;
+	map_sz = roundup(map_sz, page_sz);
+	return map_sz;
+}
+
+static size_t bpf_map_mmap_sz(const struct bpf_map *map)
+{
+	const long page_sz = sysconf(_SC_PAGE_SIZE);
+
+	switch (map->def.type) {
+	case BPF_MAP_TYPE_ARRAY:
+	case BPF_MAP_TYPE_PERCPU_ARRAY:
+		return array_map_mmap_sz(map->def.value_size, map->def.max_entries);
+	case BPF_MAP_TYPE_ARENA:
+		return page_sz * map->def.max_entries;
+	default:
+		return 0; /* not supported */
+	}
+}
+
+static int bpf_map_mmap_resize(struct bpf_map *map, size_t old_sz, size_t new_sz)
+{
+	void *mmaped;
+
+	if (!map->mmaped)
+		return -EINVAL;
+
+	if (old_sz == new_sz)
+		return 0;
+
+	mmaped = mmap(NULL, new_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (mmaped == MAP_FAILED)
+		return -errno;
+
+	memcpy(mmaped, map->mmaped, min(old_sz, new_sz));
+	munmap(map->mmaped, old_sz);
+	map->mmaped = mmaped;
+	return 0;
+}
+
+static char *internal_map_name(struct bpf_object *obj, const char *real_name,
+			       enum libbpf_map_type type)
+{
+	char map_name[BPF_OBJ_NAME_LEN], *p;
+	int pfx_len, sfx_len = max((size_t)7, strlen(real_name));
+
+	/* This is one of the more confusing parts of libbpf for various
+	 * reasons, some of which are historical. The original idea for naming
+	 * internal names was to include as much of BPF object name prefix as
+	 * possible, so that it can be distinguished from similar internal
+	 * maps of a different BPF object.
+	 * As an example, let's say we have bpf_object named 'my_object_name'
+	 * and internal map corresponding to '.rodata' ELF section. The final
+	 * map name advertised to user and to the kernel will be
+	 * 'my_objec.rodata', taking first 8 characters of object name and
+	 * entire 7 characters of '.rodata'.
+	 * Somewhat confusingly, if internal map ELF section name is shorter
+	 * than 7 characters, e.g., '.bss', we still reserve 7 characters
+	 * for the suffix, even though we only have 4 actual characters, and
+	 * resulting map will be called 'my_objec.bss', not even using all 15
+	 * characters allowed by the kernel. Oh well, at least the truncated
+	 * object name is somewhat consistent in this case. But if the map
+	 * name is '.kconfig', we'll still have entirety of '.kconfig' added
+	 * (8 chars) and thus will be left with only first 7 characters of the
+	 * object name ('my_obje'). Happy guessing, user, that the final map
+	 * name will be "my_obje.kconfig".
+	 * Now, with libbpf starting to support arbitrarily named .rodata.*
+	 * and .data.* data sections, it's possible that ELF section name is
+	 * longer than allowed 15 chars, so we now need to be careful to take
+	 * only up to 15 first characters of ELF name, taking no BPF object
+	 * name characters at all. So '.rodata.abracadabra' will result in
+	 * '.rodata.abracad' kernel and user-visible name.
+	 * We need to keep this convoluted logic intact for .data, .bss and
+	 * .rodata maps, but for new custom .data.custom and .rodata.custom
+	 * maps we use their ELF names as is, not prepending bpf_object name
+	 * in front. We still need to truncate them to 15 characters for the
+	 * kernel. Full name can be recovered for such maps by using DATASEC
+	 * BTF type associated with such map's value type, though.
+	 */
+	if (sfx_len >= BPF_OBJ_NAME_LEN)
+		sfx_len = BPF_OBJ_NAME_LEN - 1;
+
+	/*
+	 * Don't prefix the bpf_object name if this is a custom dot map
+	 * (containing two or more dots) or a percpu data map.
+	 */
+	if (strchr(real_name + 1, '.') != NULL || type == LIBBPF_MAP_PERCPU)
+		pfx_len = 0;
+	else
+		pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1, strlen(obj->name));
+
+	snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
+		 sfx_len, real_name);
+
+	/* sanities map name to characters allowed by kernel */
+	for (p = map_name; *p && p < map_name + sizeof(map_name); p++)
+		if (!isalnum(*p) && *p != '_' && *p != '.')
+			*p = '_';
+
+	return strdup(map_name);
+}
+
+static int
+map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map);
+
+/* Internal BPF map is mmap()'able only if at least one of corresponding
+ * DATASEC's VARs are to be exposed through BPF skeleton. I.e., it's a GLOBAL
+ * variable and it's not marked as __hidden (which turns it into, effectively,
+ * a STATIC variable).
+ */
+static bool map_is_mmapable(struct bpf_object *obj, struct bpf_map *map)
+{
+	const struct btf_type *t, *vt;
+	struct btf_var_secinfo *vsi;
+	int i, n;
+
+	if (!map->btf_value_type_id)
+		return false;
+
+	/*
+	 * The internal PERCPU maps are not mmapable because the underlying
+	 * percpu_array maps do not have mmap support.
+	 */
+	if (map->libbpf_type == LIBBPF_MAP_PERCPU)
+		return false;
+
+	t = btf__type_by_id(obj->btf, map->btf_value_type_id);
+	if (!btf_is_datasec(t))
+		return false;
+
+	vsi = btf_var_secinfos(t);
+	for (i = 0, n = btf_vlen(t); i < n; i++, vsi++) {
+		vt = btf__type_by_id(obj->btf, vsi->type);
+		if (!btf_is_var(vt))
+			continue;
+
+		if (btf_var(vt)->linkage != BTF_VAR_STATIC)
+			return true;
+	}
+
+	return false;
+}
+
+static int
+bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
+			      const char *real_name, int sec_idx, void *data, size_t data_sz)
+{
+	bool is_percpu = type == LIBBPF_MAP_PERCPU;
+	struct bpf_map_def *def;
+	struct bpf_map *map;
+	size_t mmap_sz;
+	int err;
+
+	map = bpf_object__add_map(obj);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	map->libbpf_type = type;
+	map->sec_idx = sec_idx;
+	map->sec_offset = 0;
+	map->real_name = strdup(real_name);
+	map->name = internal_map_name(obj, real_name, type);
+	if (!map->real_name || !map->name) {
+		zfree(&map->real_name);
+		zfree(&map->name);
+		return -ENOMEM;
+	}
+
+	def = &map->def;
+	def->type = is_percpu ? BPF_MAP_TYPE_PERCPU_ARRAY : BPF_MAP_TYPE_ARRAY;
+	def->key_size = sizeof(int);
+	def->value_size = data_sz;
+	def->max_entries = 1;
+	def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
+		? BPF_F_RDONLY_PROG : 0;
+
+	/* failures are fine because of maps like .rodata.str1.1 */
+	(void) map_fill_btf_type_info(obj, map);
+
+	if (map_is_mmapable(obj, map))
+		def->map_flags |= BPF_F_MMAPABLE;
+
+	pr_debug("map '%s' (global %sdata): at sec_idx %d, offset %zu, flags %x.\n",
+		 map->name, is_percpu ? "percpu " : "", map->sec_idx,
+		 map->sec_offset, def->map_flags);
+
+	mmap_sz = bpf_map_mmap_sz(map);
+	map->mmaped = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
+			   MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (map->mmaped == MAP_FAILED) {
+		err = -errno;
+		map->mmaped = NULL;
+		pr_warn("failed to alloc map '%s' content buffer: %s\n", map->name, errstr(err));
+		zfree(&map->real_name);
+		zfree(&map->name);
+		return err;
+	}
+
+	if (data)
+		memcpy(map->mmaped, data, data_sz);
+
+	pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
+	return 0;
+}
+
+static int bpf_object__init_global_data_maps(struct bpf_object *obj)
+{
+	struct elf_sec_desc *sec_desc;
+	const char *sec_name;
+	int err = 0, sec_idx;
+
+	/*
+	 * Populate obj->maps with libbpf internal maps.
+	 */
+	for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) {
+		sec_desc = &obj->efile.secs[sec_idx];
+
+		/* Skip recognized sections with size 0. */
+		if (!sec_desc->data || sec_desc->data->d_size == 0)
+			continue;
+
+		switch (sec_desc->sec_type) {
+		case SEC_DATA:
+			sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx));
+			err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
+							    sec_name, sec_idx,
+							    sec_desc->data->d_buf,
+							    sec_desc->data->d_size);
+			break;
+		case SEC_RODATA:
+			obj->has_rodata = true;
+			sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx));
+			err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
+							    sec_name, sec_idx,
+							    sec_desc->data->d_buf,
+							    sec_desc->data->d_size);
+			break;
+		case SEC_BSS:
+			sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx));
+			err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
+							    sec_name, sec_idx,
+							    NULL,
+							    sec_desc->data->d_size);
+			break;
+		case SEC_PERCPU:
+			sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx));
+			err = bpf_object__init_internal_map(obj, LIBBPF_MAP_PERCPU,
+							    sec_name, sec_idx,
+							    sec_desc->data->d_buf,
+							    sec_desc->data->d_size);
+			break;
+		default:
+			/* skip */
+			break;
+		}
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+
+static struct extern_desc *find_extern_by_name(const struct bpf_object *obj,
+					       const void *name)
+{
+	int i;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		if (strcmp(obj->externs[i].name, name) == 0)
+			return &obj->externs[i];
+	}
+	return NULL;
+}
+
+static struct extern_desc *find_extern_by_name_with_len(const struct bpf_object *obj,
+							const void *name, int len)
+{
+	const char *ext_name;
+	int i;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext_name = obj->externs[i].name;
+		if (strlen(ext_name) == len && strncmp(ext_name, name, len) == 0)
+			return &obj->externs[i];
+	}
+	return NULL;
+}
+
+static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val,
+			      char value)
+{
+	switch (ext->kcfg.type) {
+	case KCFG_BOOL:
+		if (value == 'm') {
+			pr_warn("extern (kcfg) '%s': value '%c' implies tristate or char type\n",
+				ext->name, value);
+			return -EINVAL;
+		}
+		*(bool *)ext_val = value == 'y' ? true : false;
+		break;
+	case KCFG_TRISTATE:
+		if (value == 'y')
+			*(enum libbpf_tristate *)ext_val = TRI_YES;
+		else if (value == 'm')
+			*(enum libbpf_tristate *)ext_val = TRI_MODULE;
+		else /* value == 'n' */
+			*(enum libbpf_tristate *)ext_val = TRI_NO;
+		break;
+	case KCFG_CHAR:
+		*(char *)ext_val = value;
+		break;
+	case KCFG_UNKNOWN:
+	case KCFG_INT:
+	case KCFG_CHAR_ARR:
+	default:
+		pr_warn("extern (kcfg) '%s': value '%c' implies bool, tristate, or char type\n",
+			ext->name, value);
+		return -EINVAL;
+	}
+	ext->is_set = true;
+	return 0;
+}
+
+static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val,
+			      const char *value)
+{
+	size_t len;
+
+	if (ext->kcfg.type != KCFG_CHAR_ARR) {
+		pr_warn("extern (kcfg) '%s': value '%s' implies char array type\n",
+			ext->name, value);
+		return -EINVAL;
+	}
+
+	len = strlen(value);
+	if (len < 2 || value[len - 1] != '"') {
+		pr_warn("extern (kcfg) '%s': invalid string config '%s'\n",
+			ext->name, value);
+		return -EINVAL;
+	}
+
+	/* strip quotes */
+	len -= 2;
+	if (len >= ext->kcfg.sz) {
+		pr_warn("extern (kcfg) '%s': long string '%s' of (%zu bytes) truncated to %d bytes\n",
+			ext->name, value, len, ext->kcfg.sz - 1);
+		len = ext->kcfg.sz - 1;
+	}
+	memcpy(ext_val, value + 1, len);
+	ext_val[len] = '\0';
+	ext->is_set = true;
+	return 0;
+}
+
+static int parse_u64(const char *value, __u64 *res)
+{
+	char *value_end;
+	int err;
+
+	errno = 0;
+	*res = strtoull(value, &value_end, 0);
+	if (errno) {
+		err = -errno;
+		pr_warn("failed to parse '%s': %s\n", value, errstr(err));
+		return err;
+	}
+	if (*value_end) {
+		pr_warn("failed to parse '%s' as integer completely\n", value);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v)
+{
+	int bit_sz = ext->kcfg.sz * 8;
+
+	if (ext->kcfg.sz == 8)
+		return true;
+
+	/* Validate that value stored in u64 fits in integer of `ext->sz`
+	 * bytes size without any loss of information. If the target integer
+	 * is signed, we rely on the following limits of integer type of
+	 * Y bits and subsequent transformation:
+	 *
+	 *     -2^(Y-1) <= X           <= 2^(Y-1) - 1
+	 *            0 <= X + 2^(Y-1) <= 2^Y - 1
+	 *            0 <= X + 2^(Y-1) <  2^Y
+	 *
+	 *  For unsigned target integer, check that all the (64 - Y) bits are
+	 *  zero.
+	 */
+	if (ext->kcfg.is_signed)
+		return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz);
+	else
+		return (v >> bit_sz) == 0;
+}
+
+static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val,
+			      __u64 value)
+{
+	if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR &&
+	    ext->kcfg.type != KCFG_BOOL) {
+		pr_warn("extern (kcfg) '%s': value '%llu' implies integer, char, or boolean type\n",
+			ext->name, (unsigned long long)value);
+		return -EINVAL;
+	}
+	if (ext->kcfg.type == KCFG_BOOL && value > 1) {
+		pr_warn("extern (kcfg) '%s': value '%llu' isn't boolean compatible\n",
+			ext->name, (unsigned long long)value);
+		return -EINVAL;
+
+	}
+	if (!is_kcfg_value_in_range(ext, value)) {
+		pr_warn("extern (kcfg) '%s': value '%llu' doesn't fit in %d bytes\n",
+			ext->name, (unsigned long long)value, ext->kcfg.sz);
+		return -ERANGE;
+	}
+	switch (ext->kcfg.sz) {
+	case 1:
+		*(__u8 *)ext_val = value;
+		break;
+	case 2:
+		*(__u16 *)ext_val = value;
+		break;
+	case 4:
+		*(__u32 *)ext_val = value;
+		break;
+	case 8:
+		*(__u64 *)ext_val = value;
+		break;
+	default:
+		return -EINVAL;
+	}
+	ext->is_set = true;
+	return 0;
+}
+
+static int bpf_object__process_kconfig_line(struct bpf_object *obj,
+					    char *buf, void *data)
+{
+	struct extern_desc *ext;
+	char *sep, *value;
+	int len, err = 0;
+	void *ext_val;
+	__u64 num;
+
+	if (!str_has_pfx(buf, "CONFIG_"))
+		return 0;
+
+	sep = strchr(buf, '=');
+	if (!sep) {
+		pr_warn("failed to parse '%s': no separator\n", buf);
+		return -EINVAL;
+	}
+
+	/* Trim ending '\n' */
+	len = strlen(buf);
+	if (buf[len - 1] == '\n')
+		buf[len - 1] = '\0';
+	/* Split on '=' and ensure that a value is present. */
+	*sep = '\0';
+	if (!sep[1]) {
+		*sep = '=';
+		pr_warn("failed to parse '%s': no value\n", buf);
+		return -EINVAL;
+	}
+
+	ext = find_extern_by_name(obj, buf);
+	if (!ext || ext->is_set)
+		return 0;
+
+	ext_val = data + ext->kcfg.data_off;
+	value = sep + 1;
+
+	switch (*value) {
+	case 'y': case 'n': case 'm':
+		err = set_kcfg_value_tri(ext, ext_val, *value);
+		break;
+	case '"':
+		err = set_kcfg_value_str(ext, ext_val, value);
+		break;
+	default:
+		/* assume integer */
+		err = parse_u64(value, &num);
+		if (err) {
+			pr_warn("extern (kcfg) '%s': value '%s' isn't a valid integer\n", ext->name, value);
+			return err;
+		}
+		if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) {
+			pr_warn("extern (kcfg) '%s': value '%s' implies integer type\n", ext->name, value);
+			return -EINVAL;
+		}
+		err = set_kcfg_value_num(ext, ext_val, num);
+		break;
+	}
+	if (err)
+		return err;
+	pr_debug("extern (kcfg) '%s': set to %s\n", ext->name, value);
+	return 0;
+}
+
+static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data)
+{
+	char buf[PATH_MAX];
+	struct utsname uts;
+	int len, err = 0;
+	gzFile file;
+
+	uname(&uts);
+	len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release);
+	if (len < 0)
+		return -EINVAL;
+	else if (len >= PATH_MAX)
+		return -ENAMETOOLONG;
+
+	/* gzopen also accepts uncompressed files. */
+	file = gzopen(buf, "re");
+	if (!file)
+		file = gzopen("/proc/config.gz", "re");
+
+	if (!file) {
+		pr_warn("failed to open system Kconfig\n");
+		return -ENOENT;
+	}
+
+	while (gzgets(file, buf, sizeof(buf))) {
+		err = bpf_object__process_kconfig_line(obj, buf, data);
+		if (err) {
+			pr_warn("error parsing system Kconfig line '%s': %s\n",
+				buf, errstr(err));
+			goto out;
+		}
+	}
+
+out:
+	gzclose(file);
+	return err;
+}
+
+static int bpf_object__read_kconfig_mem(struct bpf_object *obj,
+					const char *config, void *data)
+{
+	char buf[PATH_MAX];
+	int err = 0;
+	FILE *file;
+
+	file = fmemopen((void *)config, strlen(config), "r");
+	if (!file) {
+		err = -errno;
+		pr_warn("failed to open in-memory Kconfig: %s\n", errstr(err));
+		return err;
+	}
+
+	while (fgets(buf, sizeof(buf), file)) {
+		err = bpf_object__process_kconfig_line(obj, buf, data);
+		if (err) {
+			pr_warn("error parsing in-memory Kconfig line '%s': %s\n",
+				buf, errstr(err));
+			break;
+		}
+	}
+
+	fclose(file);
+	return err;
+}
+
+static int bpf_object__init_kconfig_map(struct bpf_object *obj)
+{
+	struct extern_desc *last_ext = NULL, *ext;
+	size_t map_sz;
+	int i, err;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext = &obj->externs[i];
+		if (ext->type == EXT_KCFG)
+			last_ext = ext;
+	}
+
+	if (!last_ext)
+		return 0;
+
+	map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz;
+	err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
+					    ".kconfig", obj->efile.symbols_shndx,
+					    NULL, map_sz);
+	if (err)
+		return err;
+
+	obj->kconfig_map_idx = obj->nr_maps - 1;
+
+	return 0;
+}
+
+const struct btf_type *
+skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
+{
+	const struct btf_type *t = btf__type_by_id(btf, id);
+
+	if (res_id)
+		*res_id = id;
+
+	while (btf_is_mod(t) || btf_is_typedef(t)) {
+		if (res_id)
+			*res_id = t->type;
+		t = btf__type_by_id(btf, t->type);
+	}
+
+	return t;
+}
+
+static const struct btf_type *
+resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
+{
+	const struct btf_type *t;
+
+	t = skip_mods_and_typedefs(btf, id, NULL);
+	if (!btf_is_ptr(t))
+		return NULL;
+
+	t = skip_mods_and_typedefs(btf, t->type, res_id);
+
+	return btf_is_func_proto(t) ? t : NULL;
+}
+
+static const char *__btf_kind_str(__u16 kind)
+{
+	switch (kind) {
+	case BTF_KIND_UNKN: return "void";
+	case BTF_KIND_INT: return "int";
+	case BTF_KIND_PTR: return "ptr";
+	case BTF_KIND_ARRAY: return "array";
+	case BTF_KIND_STRUCT: return "struct";
+	case BTF_KIND_UNION: return "union";
+	case BTF_KIND_ENUM: return "enum";
+	case BTF_KIND_FWD: return "fwd";
+	case BTF_KIND_TYPEDEF: return "typedef";
+	case BTF_KIND_VOLATILE: return "volatile";
+	case BTF_KIND_CONST: return "const";
+	case BTF_KIND_RESTRICT: return "restrict";
+	case BTF_KIND_FUNC: return "func";
+	case BTF_KIND_FUNC_PROTO: return "func_proto";
+	case BTF_KIND_VAR: return "var";
+	case BTF_KIND_DATASEC: return "datasec";
+	case BTF_KIND_FLOAT: return "float";
+	case BTF_KIND_DECL_TAG: return "decl_tag";
+	case BTF_KIND_TYPE_TAG: return "type_tag";
+	case BTF_KIND_ENUM64: return "enum64";
+	default: return "unknown";
+	}
+}
+
+const char *btf_kind_str(const struct btf_type *t)
+{
+	return __btf_kind_str(btf_kind(t));
+}
+
+/*
+ * Fetch integer attribute of BTF map definition. Such attributes are
+ * represented using a pointer to an array, in which dimensionality of array
+ * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
+ * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
+ * type definition, while using only sizeof(void *) space in ELF data section.
+ */
+static bool get_map_field_int(const char *map_name, const struct btf *btf,
+			      const struct btf_member *m, __u32 *res)
+{
+	const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
+	const char *name = btf__name_by_offset(btf, m->name_off);
+	const struct btf_array *arr_info;
+	const struct btf_type *arr_t;
+
+	if (!btf_is_ptr(t)) {
+		pr_warn("map '%s': attr '%s': expected PTR, got %s.\n",
+			map_name, name, btf_kind_str(t));
+		return false;
+	}
+
+	arr_t = btf__type_by_id(btf, t->type);
+	if (!arr_t) {
+		pr_warn("map '%s': attr '%s': type [%u] not found.\n",
+			map_name, name, t->type);
+		return false;
+	}
+	if (!btf_is_array(arr_t)) {
+		pr_warn("map '%s': attr '%s': expected ARRAY, got %s.\n",
+			map_name, name, btf_kind_str(arr_t));
+		return false;
+	}
+	arr_info = btf_array(arr_t);
+	*res = arr_info->nelems;
+	return true;
+}
+
+static bool get_map_field_long(const char *map_name, const struct btf *btf,
+			       const struct btf_member *m, __u64 *res)
+{
+	const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
+	const char *name = btf__name_by_offset(btf, m->name_off);
+
+	if (btf_is_ptr(t)) {
+		__u32 res32;
+		bool ret;
+
+		ret = get_map_field_int(map_name, btf, m, &res32);
+		if (ret)
+			*res = (__u64)res32;
+		return ret;
+	}
+
+	if (!btf_is_enum(t) && !btf_is_enum64(t)) {
+		pr_warn("map '%s': attr '%s': expected ENUM or ENUM64, got %s.\n",
+			map_name, name, btf_kind_str(t));
+		return false;
+	}
+
+	if (btf_vlen(t) != 1) {
+		pr_warn("map '%s': attr '%s': invalid __ulong\n",
+			map_name, name);
+		return false;
+	}
+
+	if (btf_is_enum(t)) {
+		const struct btf_enum *e = btf_enum(t);
+
+		*res = e->val;
+	} else {
+		const struct btf_enum64 *e = btf_enum64(t);
+
+		*res = btf_enum64_value(e);
+	}
+	return true;
+}
+
+static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name)
+{
+	int len;
+
+	len = snprintf(buf, buf_sz, "%s/%s", path, name);
+	if (len < 0)
+		return -EINVAL;
+	if (len >= buf_sz)
+		return -ENAMETOOLONG;
+
+	return 0;
+}
+
+static int build_map_pin_path(struct bpf_map *map, const char *path)
+{
+	char buf[PATH_MAX];
+	int err;
+
+	if (!path)
+		path = BPF_FS_DEFAULT_PATH;
+
+	err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map));
+	if (err)
+		return err;
+
+	return bpf_map__set_pin_path(map, buf);
+}
+
+/* should match definition in bpf_helpers.h */
+enum libbpf_pin_type {
+	LIBBPF_PIN_NONE,
+	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+	LIBBPF_PIN_BY_NAME,
+};
+
+int parse_btf_map_def(const char *map_name, struct btf *btf,
+		      const struct btf_type *def_t, bool strict,
+		      struct btf_map_def *map_def, struct btf_map_def *inner_def)
+{
+	const struct btf_type *t;
+	const struct btf_member *m;
+	bool is_inner = inner_def == NULL;
+	int vlen, i;
+
+	vlen = btf_vlen(def_t);
+	m = btf_members(def_t);
+	for (i = 0; i < vlen; i++, m++) {
+		const char *name = btf__name_by_offset(btf, m->name_off);
+
+		if (!name) {
+			pr_warn("map '%s': invalid field #%d.\n", map_name, i);
+			return -EINVAL;
+		}
+		if (strcmp(name, "type") == 0) {
+			if (!get_map_field_int(map_name, btf, m, &map_def->map_type))
+				return -EINVAL;
+			map_def->parts |= MAP_DEF_MAP_TYPE;
+		} else if (strcmp(name, "max_entries") == 0) {
+			if (!get_map_field_int(map_name, btf, m, &map_def->max_entries))
+				return -EINVAL;
+			map_def->parts |= MAP_DEF_MAX_ENTRIES;
+		} else if (strcmp(name, "map_flags") == 0) {
+			if (!get_map_field_int(map_name, btf, m, &map_def->map_flags))
+				return -EINVAL;
+			map_def->parts |= MAP_DEF_MAP_FLAGS;
+		} else if (strcmp(name, "numa_node") == 0) {
+			if (!get_map_field_int(map_name, btf, m, &map_def->numa_node))
+				return -EINVAL;
+			map_def->parts |= MAP_DEF_NUMA_NODE;
+		} else if (strcmp(name, "key_size") == 0) {
+			__u32 sz;
+
+			if (!get_map_field_int(map_name, btf, m, &sz))
+				return -EINVAL;
+			if (map_def->key_size && map_def->key_size != sz) {
+				pr_warn("map '%s': conflicting key size %u != %u.\n",
+					map_name, map_def->key_size, sz);
+				return -EINVAL;
+			}
+			map_def->key_size = sz;
+			map_def->parts |= MAP_DEF_KEY_SIZE;
+		} else if (strcmp(name, "key") == 0) {
+			__s64 sz;
+
+			t = btf__type_by_id(btf, m->type);
+			if (!t) {
+				pr_warn("map '%s': key type [%u] not found.\n",
+					map_name, m->type);
+				return -EINVAL;
+			}
+			if (!btf_is_ptr(t)) {
+				pr_warn("map '%s': key spec is not PTR: %s.\n",
+					map_name, btf_kind_str(t));
+				return -EINVAL;
+			}
+			sz = btf__resolve_size(btf, t->type);
+			if (sz < 0) {
+				pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
+					map_name, t->type, (ssize_t)sz);
+				return sz;
+			}
+			if (map_def->key_size && map_def->key_size != sz) {
+				pr_warn("map '%s': conflicting key size %u != %zd.\n",
+					map_name, map_def->key_size, (ssize_t)sz);
+				return -EINVAL;
+			}
+			map_def->key_size = sz;
+			map_def->key_type_id = t->type;
+			map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE;
+		} else if (strcmp(name, "value_size") == 0) {
+			__u32 sz;
+
+			if (!get_map_field_int(map_name, btf, m, &sz))
+				return -EINVAL;
+			if (map_def->value_size && map_def->value_size != sz) {
+				pr_warn("map '%s': conflicting value size %u != %u.\n",
+					map_name, map_def->value_size, sz);
+				return -EINVAL;
+			}
+			map_def->value_size = sz;
+			map_def->parts |= MAP_DEF_VALUE_SIZE;
+		} else if (strcmp(name, "value") == 0) {
+			__s64 sz;
+
+			t = btf__type_by_id(btf, m->type);
+			if (!t) {
+				pr_warn("map '%s': value type [%u] not found.\n",
+					map_name, m->type);
+				return -EINVAL;
+			}
+			if (!btf_is_ptr(t)) {
+				pr_warn("map '%s': value spec is not PTR: %s.\n",
+					map_name, btf_kind_str(t));
+				return -EINVAL;
+			}
+			sz = btf__resolve_size(btf, t->type);
+			if (sz < 0) {
+				pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
+					map_name, t->type, (ssize_t)sz);
+				return sz;
+			}
+			if (map_def->value_size && map_def->value_size != sz) {
+				pr_warn("map '%s': conflicting value size %u != %zd.\n",
+					map_name, map_def->value_size, (ssize_t)sz);
+				return -EINVAL;
+			}
+			map_def->value_size = sz;
+			map_def->value_type_id = t->type;
+			map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE;
+		}
+		else if (strcmp(name, "values") == 0) {
+			bool is_map_in_map = bpf_map_type__is_map_in_map(map_def->map_type);
+			bool is_prog_array = map_def->map_type == BPF_MAP_TYPE_PROG_ARRAY;
+			const char *desc = is_map_in_map ? "map-in-map inner" : "prog-array value";
+			char inner_map_name[128];
+			int err;
+
+			if (is_inner) {
+				pr_warn("map '%s': multi-level inner maps not supported.\n",
+					map_name);
+				return -ENOTSUP;
+			}
+			if (i != vlen - 1) {
+				pr_warn("map '%s': '%s' member should be last.\n",
+					map_name, name);
+				return -EINVAL;
+			}
+			if (!is_map_in_map && !is_prog_array) {
+				pr_warn("map '%s': should be map-in-map or prog-array.\n",
+					map_name);
+				return -ENOTSUP;
+			}
+			if (map_def->value_size && map_def->value_size != 4) {
+				pr_warn("map '%s': conflicting value size %u != 4.\n",
+					map_name, map_def->value_size);
+				return -EINVAL;
+			}
+			map_def->value_size = 4;
+			t = btf__type_by_id(btf, m->type);
+			if (!t) {
+				pr_warn("map '%s': %s type [%u] not found.\n",
+					map_name, desc, m->type);
+				return -EINVAL;
+			}
+			if (!btf_is_array(t) || btf_array(t)->nelems) {
+				pr_warn("map '%s': %s spec is not a zero-sized array.\n",
+					map_name, desc);
+				return -EINVAL;
+			}
+			t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL);
+			if (!btf_is_ptr(t)) {
+				pr_warn("map '%s': %s def is of unexpected kind %s.\n",
+					map_name, desc, btf_kind_str(t));
+				return -EINVAL;
+			}
+			t = skip_mods_and_typedefs(btf, t->type, NULL);
+			if (is_prog_array) {
+				if (!btf_is_func_proto(t)) {
+					pr_warn("map '%s': prog-array value def is of unexpected kind %s.\n",
+						map_name, btf_kind_str(t));
+					return -EINVAL;
+				}
+				continue;
+			}
+			if (!btf_is_struct(t)) {
+				pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
+					map_name, btf_kind_str(t));
+				return -EINVAL;
+			}
+
+			snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name);
+			err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL);
+			if (err)
+				return err;
+
+			map_def->parts |= MAP_DEF_INNER_MAP;
+		} else if (strcmp(name, "pinning") == 0) {
+			__u32 val;
+
+			if (is_inner) {
+				pr_warn("map '%s': inner def can't be pinned.\n", map_name);
+				return -EINVAL;
+			}
+			if (!get_map_field_int(map_name, btf, m, &val))
+				return -EINVAL;
+			if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) {
+				pr_warn("map '%s': invalid pinning value %u.\n",
+					map_name, val);
+				return -EINVAL;
+			}
+			map_def->pinning = val;
+			map_def->parts |= MAP_DEF_PINNING;
+		} else if (strcmp(name, "map_extra") == 0) {
+			__u64 map_extra;
+
+			if (!get_map_field_long(map_name, btf, m, &map_extra))
+				return -EINVAL;
+			map_def->map_extra = map_extra;
+			map_def->parts |= MAP_DEF_MAP_EXTRA;
+		} else {
+			if (strict) {
+				pr_warn("map '%s': unknown field '%s'.\n", map_name, name);
+				return -ENOTSUP;
+			}
+			pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name);
+		}
+	}
+
+	if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) {
+		pr_warn("map '%s': map type isn't specified.\n", map_name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static size_t adjust_ringbuf_sz(size_t sz)
+{
+	__u32 page_sz = sysconf(_SC_PAGE_SIZE);
+	__u32 mul;
+
+	/* if user forgot to set any size, make sure they see error */
+	if (sz == 0)
+		return 0;
+	/* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be
+	 * a power-of-2 multiple of kernel's page size. If user diligently
+	 * satisfied these conditions, pass the size through.
+	 */
+	if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz))
+		return sz;
+
+	/* Otherwise find closest (page_sz * power_of_2) product bigger than
+	 * user-set size to satisfy both user size request and kernel
+	 * requirements and substitute correct max_entries for map creation.
+	 */
+	for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) {
+		if (mul * page_sz > sz)
+			return mul * page_sz;
+	}
+
+	/* if it's impossible to satisfy the conditions (i.e., user size is
+	 * very close to UINT_MAX but is not a power-of-2 multiple of
+	 * page_size) then just return original size and let kernel reject it
+	 */
+	return sz;
+}
+
+static bool map_is_ringbuf(const struct bpf_map *map)
+{
+	return map->def.type == BPF_MAP_TYPE_RINGBUF ||
+	       map->def.type == BPF_MAP_TYPE_USER_RINGBUF;
+}
+
+static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def)
+{
+	map->def.type = def->map_type;
+	map->def.key_size = def->key_size;
+	map->def.value_size = def->value_size;
+	map->def.max_entries = def->max_entries;
+	map->def.map_flags = def->map_flags;
+	map->map_extra = def->map_extra;
+
+	map->numa_node = def->numa_node;
+	map->btf_key_type_id = def->key_type_id;
+	map->btf_value_type_id = def->value_type_id;
+
+	/* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */
+	if (map_is_ringbuf(map))
+		map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries);
+
+	if (def->parts & MAP_DEF_MAP_TYPE)
+		pr_debug("map '%s': found type = %u.\n", map->name, def->map_type);
+
+	if (def->parts & MAP_DEF_KEY_TYPE)
+		pr_debug("map '%s': found key [%u], sz = %u.\n",
+			 map->name, def->key_type_id, def->key_size);
+	else if (def->parts & MAP_DEF_KEY_SIZE)
+		pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size);
+
+	if (def->parts & MAP_DEF_VALUE_TYPE)
+		pr_debug("map '%s': found value [%u], sz = %u.\n",
+			 map->name, def->value_type_id, def->value_size);
+	else if (def->parts & MAP_DEF_VALUE_SIZE)
+		pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size);
+
+	if (def->parts & MAP_DEF_MAX_ENTRIES)
+		pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries);
+	if (def->parts & MAP_DEF_MAP_FLAGS)
+		pr_debug("map '%s': found map_flags = 0x%x.\n", map->name, def->map_flags);
+	if (def->parts & MAP_DEF_MAP_EXTRA)
+		pr_debug("map '%s': found map_extra = 0x%llx.\n", map->name,
+			 (unsigned long long)def->map_extra);
+	if (def->parts & MAP_DEF_PINNING)
+		pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning);
+	if (def->parts & MAP_DEF_NUMA_NODE)
+		pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node);
+
+	if (def->parts & MAP_DEF_INNER_MAP)
+		pr_debug("map '%s': found inner map definition.\n", map->name);
+}
+
+static const char *btf_var_linkage_str(__u32 linkage)
+{
+	switch (linkage) {
+	case BTF_VAR_STATIC: return "static";
+	case BTF_VAR_GLOBAL_ALLOCATED: return "global";
+	case BTF_VAR_GLOBAL_EXTERN: return "extern";
+	default: return "unknown";
+	}
+}
+
+static int bpf_object__init_user_btf_map(struct bpf_object *obj,
+					 const struct btf_type *sec,
+					 int var_idx, int sec_idx,
+					 const Elf_Data *data, bool strict,
+					 const char *pin_root_path)
+{
+	struct btf_map_def map_def = {}, inner_def = {};
+	const struct btf_type *var, *def;
+	const struct btf_var_secinfo *vi;
+	const struct btf_var *var_extra;
+	const char *map_name;
+	struct bpf_map *map;
+	int err;
+
+	vi = btf_var_secinfos(sec) + var_idx;
+	var = btf__type_by_id(obj->btf, vi->type);
+	var_extra = btf_var(var);
+	map_name = btf__name_by_offset(obj->btf, var->name_off);
+
+	if (str_is_empty(map_name)) {
+		pr_warn("map #%d: empty name.\n", var_idx);
+		return -EINVAL;
+	}
+	if ((__u64)vi->offset + vi->size > data->d_size) {
+		pr_warn("map '%s' BTF data is corrupted.\n", map_name);
+		return -EINVAL;
+	}
+	if (!btf_is_var(var)) {
+		pr_warn("map '%s': unexpected var kind %s.\n",
+			map_name, btf_kind_str(var));
+		return -EINVAL;
+	}
+	if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
+		pr_warn("map '%s': unsupported map linkage %s.\n",
+			map_name, btf_var_linkage_str(var_extra->linkage));
+		return -EOPNOTSUPP;
+	}
+
+	def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
+	if (!btf_is_struct(def)) {
+		pr_warn("map '%s': unexpected def kind %s.\n",
+			map_name, btf_kind_str(var));
+		return -EINVAL;
+	}
+	if (def->size > vi->size) {
+		pr_warn("map '%s': invalid def size.\n", map_name);
+		return -EINVAL;
+	}
+
+	map = bpf_object__add_map(obj);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	map->name = strdup(map_name);
+	if (!map->name) {
+		pr_warn("map '%s': failed to alloc map name.\n", map_name);
+		return -ENOMEM;
+	}
+	map->libbpf_type = LIBBPF_MAP_UNSPEC;
+	map->def.type = BPF_MAP_TYPE_UNSPEC;
+	map->sec_idx = sec_idx;
+	map->sec_offset = vi->offset;
+	map->btf_var_idx = var_idx;
+	pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
+		 map_name, map->sec_idx, map->sec_offset);
+
+	err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def);
+	if (err)
+		return err;
+
+	fill_map_from_def(map, &map_def);
+
+	if (map_def.pinning == LIBBPF_PIN_BY_NAME) {
+		err = build_map_pin_path(map, pin_root_path);
+		if (err) {
+			pr_warn("map '%s': couldn't build pin path.\n", map->name);
+			return err;
+		}
+	}
+
+	if (map_def.parts & MAP_DEF_INNER_MAP) {
+		map->inner_map = calloc(1, sizeof(*map->inner_map));
+		if (!map->inner_map)
+			return -ENOMEM;
+		map->inner_map->fd = create_placeholder_fd();
+		if (map->inner_map->fd < 0)
+			return map->inner_map->fd;
+		map->inner_map->sec_idx = sec_idx;
+		map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1);
+		if (!map->inner_map->name)
+			return -ENOMEM;
+		sprintf(map->inner_map->name, "%s.inner", map_name);
+
+		fill_map_from_def(map->inner_map, &inner_def);
+	}
+
+	err = map_fill_btf_type_info(obj, map);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int init_arena_map_data(struct bpf_object *obj, struct bpf_map *map,
+			       const char *sec_name, int sec_idx,
+			       void *data, size_t data_sz)
+{
+	const long page_sz = sysconf(_SC_PAGE_SIZE);
+	const size_t data_alloc_sz = roundup(data_sz, page_sz);
+	size_t mmap_sz;
+
+	mmap_sz = bpf_map_mmap_sz(map);
+	if (data_alloc_sz > mmap_sz) {
+		pr_warn("elf: sec '%s': declared ARENA map size (%zu) is too small to hold global __arena variables of size %zu\n",
+			sec_name, mmap_sz, data_sz);
+		return -E2BIG;
+	}
+
+	obj->arena_data = malloc(data_sz);
+	if (!obj->arena_data)
+		return -ENOMEM;
+	memcpy(obj->arena_data, data, data_sz);
+	obj->arena_data_sz = data_sz;
+
+	/* make bpf_map__init_value() work for ARENA maps */
+	map->mmaped = obj->arena_data;
+
+	return 0;
+}
+
+static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
+					  const char *pin_root_path)
+{
+	const struct btf_type *sec = NULL;
+	int nr_types, i, vlen, err;
+	const struct btf_type *t;
+	const char *name;
+	Elf_Data *data;
+	Elf_Scn *scn;
+
+	if (obj->efile.btf_maps_shndx < 0)
+		return 0;
+
+	scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx);
+	data = elf_sec_data(obj, scn);
+	if (!data) {
+		pr_warn("elf: failed to get %s map definitions for %s\n",
+			MAPS_ELF_SEC, obj->path);
+		return -EINVAL;
+	}
+
+	nr_types = btf__type_cnt(obj->btf);
+	for (i = 1; i < nr_types; i++) {
+		t = btf__type_by_id(obj->btf, i);
+		if (!btf_is_datasec(t))
+			continue;
+		name = btf__name_by_offset(obj->btf, t->name_off);
+		if (strcmp(name, MAPS_ELF_SEC) == 0) {
+			sec = t;
+			obj->efile.btf_maps_sec_btf_id = i;
+			break;
+		}
+	}
+
+	if (!sec) {
+		pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
+		return -ENOENT;
+	}
+
+	vlen = btf_vlen(sec);
+	for (i = 0; i < vlen; i++) {
+		err = bpf_object__init_user_btf_map(obj, sec, i,
+						    obj->efile.btf_maps_shndx,
+						    data, strict,
+						    pin_root_path);
+		if (err)
+			return err;
+	}
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		struct bpf_map *map = &obj->maps[i];
+
+		if (map->def.type != BPF_MAP_TYPE_ARENA)
+			continue;
+
+		if (obj->arena_map_idx >= 0) {
+			pr_warn("map '%s': only single ARENA map is supported (map '%s' is also ARENA)\n",
+				map->name, obj->maps[obj->arena_map_idx].name);
+			return -EINVAL;
+		}
+		obj->arena_map_idx = i;
+
+		if (obj->efile.arena_data) {
+			err = init_arena_map_data(obj, map, ARENA_SEC, obj->efile.arena_data_shndx,
+						  obj->efile.arena_data->d_buf,
+						  obj->efile.arena_data->d_size);
+			if (err)
+				return err;
+		}
+	}
+	if (obj->efile.arena_data && obj->arena_map_idx < 0) {
+		pr_warn("elf: sec '%s': to use global __arena variables the ARENA map should be explicitly declared in SEC(\".maps\")\n",
+			ARENA_SEC);
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static int bpf_object__init_maps(struct bpf_object *obj,
+				 const struct bpf_object_open_opts *opts)
+{
+	const char *pin_root_path;
+	bool strict;
+	int err = 0;
+
+	strict = !OPTS_GET(opts, relaxed_maps, false);
+	pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
+
+	err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
+	err = err ?: bpf_object__init_global_data_maps(obj);
+	err = err ?: bpf_object__init_kconfig_map(obj);
+	err = err ?: bpf_object_init_struct_ops(obj);
+
+	return err;
+}
+
+static bool section_have_execinstr(struct bpf_object *obj, int idx)
+{
+	Elf64_Shdr *sh;
+
+	sh = elf_sec_hdr(obj, elf_sec_by_idx(obj, idx));
+	if (!sh)
+		return false;
+
+	return sh->sh_flags & SHF_EXECINSTR;
+}
+
+static bool starts_with_qmark(const char *s)
+{
+	return s && s[0] == '?';
+}
+
+static bool btf_needs_sanitization(struct bpf_object *obj)
+{
+	bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC);
+	bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC);
+	bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
+	bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
+	bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG);
+	bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG);
+	bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64);
+	bool has_qmark_datasec = kernel_supports(obj, FEAT_BTF_QMARK_DATASEC);
+	bool has_layout = kernel_supports(obj, FEAT_BTF_LAYOUT);
+
+	return !has_func || !has_datasec || !has_func_global || !has_float ||
+	       !has_decl_tag || !has_type_tag || !has_enum64 || !has_qmark_datasec ||
+	       !has_layout;
+}
+
+struct btf *bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *orig_btf)
+{
+	bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC);
+	bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC);
+	bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
+	bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
+	bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG);
+	bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG);
+	bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64);
+	bool has_qmark_datasec = kernel_supports(obj, FEAT_BTF_QMARK_DATASEC);
+	bool has_layout = kernel_supports(obj, FEAT_BTF_LAYOUT);
+	int enum64_placeholder_id = 0;
+	const struct btf_header *hdr;
+	struct btf *btf = NULL;
+	const void *raw_data;
+	struct btf_type *t;
+	int i, j, vlen;
+	__u32 sz;
+	int err;
+
+	/* clone BTF to sanitize a copy and leave the original intact */
+	raw_data = btf__raw_data(orig_btf, &sz);
+	if (!raw_data)
+		return ERR_PTR(-ENOMEM);
+	/* btf_header() gives us endian-safe header info */
+	hdr = btf_header(orig_btf);
+
+	if (!has_layout && hdr->hdr_len >= sizeof(struct btf_header) &&
+	    (hdr->layout_len != 0 || hdr->layout_off != 0)) {
+		const struct btf_header *old_hdr = raw_data;
+		struct btf_header *new_hdr;
+		void *new_raw_data;
+		__u32 new_str_off;
+
+		/*
+		 * Need to rewrite BTF to exclude layout information and
+		 * move string section to immediately after types.
+		 */
+		new_raw_data = malloc(sz);
+		if (!new_raw_data)
+			return ERR_PTR(-ENOMEM);
+
+		memcpy(new_raw_data, raw_data, sz);
+		new_hdr = new_raw_data;
+		new_hdr->layout_off = 0;
+		new_hdr->layout_len = 0;
+		new_str_off = hdr->type_off + hdr->type_len;
+		/* Handle swapped endian case */
+		if (old_hdr->magic != hdr->magic)
+			new_hdr->str_off = bswap_32(new_str_off);
+		else
+			new_hdr->str_off = new_str_off;
+
+		memmove(new_raw_data + hdr->hdr_len + new_str_off,
+			new_raw_data + hdr->hdr_len + hdr->str_off,
+			hdr->str_len);
+		sz = hdr->hdr_len + hdr->type_off + hdr->type_len + hdr->str_len;
+		btf = btf__new(new_raw_data, sz);
+		free(new_raw_data);
+	} else {
+		btf = btf__new(raw_data, sz);
+	}
+	err = libbpf_get_error(btf);
+	if (err)
+		return ERR_PTR(err);
+
+	/* enforce 8-byte pointers for BPF-targeted BTFs */
+	btf__set_pointer_size(btf, 8);
+
+	for (i = 1; i < btf__type_cnt(btf); i++) {
+		t = (struct btf_type *)btf__type_by_id(btf, i);
+
+		if ((!has_datasec && btf_is_var(t)) || (!has_decl_tag && btf_is_decl_tag(t))) {
+			/* replace VAR/DECL_TAG with INT */
+			t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
+			/*
+			 * using size = 1 is the safest choice, 4 will be too
+			 * big and cause kernel BTF validation failure if
+			 * original variable took less than 4 bytes
+			 */
+			t->size = 1;
+			*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
+		} else if (!has_datasec && btf_is_datasec(t)) {
+			/* replace DATASEC with STRUCT */
+			const struct btf_var_secinfo *v = btf_var_secinfos(t);
+			struct btf_member *m = btf_members(t);
+			struct btf_type *vt;
+			char *name;
+
+			name = (char *)btf__name_by_offset(btf, t->name_off);
+			while (*name) {
+				if (*name == '.' || *name == '?')
+					*name = '_';
+				name++;
+			}
+
+			vlen = btf_vlen(t);
+			t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
+			for (j = 0; j < vlen; j++, v++, m++) {
+				/* order of field assignments is important */
+				m->offset = v->offset * 8;
+				m->type = v->type;
+				/* preserve variable name as member name */
+				vt = (void *)btf__type_by_id(btf, v->type);
+				m->name_off = vt->name_off;
+			}
+		} else if (!has_qmark_datasec && btf_is_datasec(t) &&
+			   starts_with_qmark(btf__name_by_offset(btf, t->name_off))) {
+			/* replace '?' prefix with '_' for DATASEC names */
+			char *name;
+
+			name = (char *)btf__name_by_offset(btf, t->name_off);
+			if (name[0] == '?')
+				name[0] = '_';
+		} else if (!has_func && btf_is_func_proto(t)) {
+			/* replace FUNC_PROTO with ENUM */
+			vlen = btf_vlen(t);
+			t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
+			t->size = sizeof(__u32); /* kernel enforced */
+		} else if (!has_func && btf_is_func(t)) {
+			/* replace FUNC with TYPEDEF */
+			t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
+		} else if (!has_func_global && btf_is_func(t)) {
+			/* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
+			t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
+		} else if (!has_float && btf_is_float(t)) {
+			/* replace FLOAT with an equally-sized empty STRUCT;
+			 * since C compilers do not accept e.g. "float" as a
+			 * valid struct name, make it anonymous
+			 */
+			t->name_off = 0;
+			t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0);
+		} else if (!has_type_tag && btf_is_type_tag(t)) {
+			/* replace TYPE_TAG with a CONST */
+			t->name_off = 0;
+			t->info = BTF_INFO_ENC(BTF_KIND_CONST, 0, 0);
+		} else if (!has_enum64 && btf_is_enum(t)) {
+			/* clear the kflag */
+			t->info = btf_type_info(btf_kind(t), btf_vlen(t), false);
+		} else if (!has_enum64 && btf_is_enum64(t)) {
+			/* replace ENUM64 with a union */
+			struct btf_member *m;
+
+			if (enum64_placeholder_id == 0) {
+				enum64_placeholder_id = btf__add_int(btf, "enum64_placeholder", 1, 0);
+				if (enum64_placeholder_id < 0) {
+					btf__free(btf);
+					return ERR_PTR(enum64_placeholder_id);
+				}
+				t = (struct btf_type *)btf__type_by_id(btf, i);
+			}
+
+			m = btf_members(t);
+			vlen = btf_vlen(t);
+			t->info = BTF_INFO_ENC(BTF_KIND_UNION, 0, vlen);
+			for (j = 0; j < vlen; j++, m++) {
+				m->type = enum64_placeholder_id;
+				m->offset = 0;
+			}
+		}
+	}
+
+	return btf;
+}
+
+static bool libbpf_needs_btf(const struct bpf_object *obj)
+{
+	return obj->efile.btf_maps_shndx >= 0 ||
+	       obj->efile.has_st_ops ||
+	       obj->nr_extern > 0;
+}
+
+static bool kernel_needs_btf(const struct bpf_object *obj)
+{
+	return obj->efile.has_st_ops;
+}
+
+static int bpf_object__init_btf(struct bpf_object *obj,
+				Elf_Data *btf_data,
+				Elf_Data *btf_ext_data)
+{
+	int err = -ENOENT;
+
+	if (btf_data) {
+		obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
+		err = libbpf_get_error(obj->btf);
+		if (err) {
+			obj->btf = NULL;
+			pr_warn("Error loading ELF section %s: %s.\n", BTF_ELF_SEC, errstr(err));
+			goto out;
+		}
+		/* enforce 8-byte pointers for BPF-targeted BTFs */
+		btf__set_pointer_size(obj->btf, 8);
+	}
+	if (btf_ext_data) {
+		struct btf_ext_info *ext_segs[3];
+		int seg_num, sec_num;
+
+		if (!obj->btf) {
+			pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
+				 BTF_EXT_ELF_SEC, BTF_ELF_SEC);
+			goto out;
+		}
+		obj->btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size);
+		err = libbpf_get_error(obj->btf_ext);
+		if (err) {
+			pr_warn("Error loading ELF section %s: %s. Ignored and continue.\n",
+				BTF_EXT_ELF_SEC, errstr(err));
+			obj->btf_ext = NULL;
+			goto out;
+		}
+
+		/* setup .BTF.ext to ELF section mapping */
+		ext_segs[0] = &obj->btf_ext->func_info;
+		ext_segs[1] = &obj->btf_ext->line_info;
+		ext_segs[2] = &obj->btf_ext->core_relo_info;
+		for (seg_num = 0; seg_num < ARRAY_SIZE(ext_segs); seg_num++) {
+			struct btf_ext_info *seg = ext_segs[seg_num];
+			const struct btf_ext_info_sec *sec;
+			const char *sec_name;
+			Elf_Scn *scn;
+
+			if (seg->sec_cnt == 0)
+				continue;
+
+			seg->sec_idxs = calloc(seg->sec_cnt, sizeof(*seg->sec_idxs));
+			if (!seg->sec_idxs) {
+				err = -ENOMEM;
+				goto out;
+			}
+
+			sec_num = 0;
+			for_each_btf_ext_sec(seg, sec) {
+				/* preventively increment index to avoid doing
+				 * this before every continue below
+				 */
+				sec_num++;
+
+				sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
+				if (str_is_empty(sec_name))
+					continue;
+				scn = elf_sec_by_name(obj, sec_name);
+				if (!scn)
+					continue;
+
+				seg->sec_idxs[sec_num - 1] = elf_ndxscn(scn);
+			}
+		}
+	}
+out:
+	if (err && libbpf_needs_btf(obj)) {
+		pr_warn("BTF is required, but is missing or corrupted.\n");
+		return err;
+	}
+	return 0;
+}
+
+static int compare_vsi_off(const void *_a, const void *_b)
+{
+	const struct btf_var_secinfo *a = _a;
+	const struct btf_var_secinfo *b = _b;
+
+	return a->offset - b->offset;
+}
+
+static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
+			     struct btf_type *t)
+{
+	__u32 size = 0, i, vars = btf_vlen(t);
+	const char *sec_name = btf__name_by_offset(btf, t->name_off);
+	struct btf_var_secinfo *vsi;
+	bool fixup_offsets = false;
+	int err;
+
+	if (!sec_name) {
+		pr_debug("No name found in string section for DATASEC kind.\n");
+		return -ENOENT;
+	}
+
+	/* Extern-backing datasecs (.ksyms, .kconfig) have their size and
+	 * variable offsets set at the previous step. Further, not every
+	 * extern BTF VAR has corresponding ELF symbol preserved, so we skip
+	 * all fixups altogether for such sections and go straight to sorting
+	 * VARs within their DATASEC.
+	 */
+	if (strcmp(sec_name, KCONFIG_SEC) == 0 || strcmp(sec_name, KSYMS_SEC) == 0)
+		goto sort_vars;
+
+	/* Clang leaves DATASEC size and VAR offsets as zeroes, so we need to
+	 * fix this up. But BPF static linker already fixes this up and fills
+	 * all the sizes and offsets during static linking. So this step has
+	 * to be optional. But the STV_HIDDEN handling is non-optional for any
+	 * non-extern DATASEC, so the variable fixup loop below handles both
+	 * functions at the same time, paying the cost of BTF VAR <-> ELF
+	 * symbol matching just once.
+	 */
+	if (t->size == 0) {
+		err = find_elf_sec_sz(obj, sec_name, &size);
+		if (err || !size) {
+			pr_debug("sec '%s': failed to determine size from ELF: size %u, err %s\n",
+				 sec_name, size, errstr(err));
+			return -ENOENT;
+		}
+
+		t->size = size;
+		fixup_offsets = true;
+	}
+
+	for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) {
+		const struct btf_type *t_var;
+		struct btf_var *var;
+		const char *var_name;
+		Elf64_Sym *sym;
+
+		t_var = btf__type_by_id(btf, vsi->type);
+		if (!t_var || !btf_is_var(t_var)) {
+			pr_debug("sec '%s': unexpected non-VAR type found\n", sec_name);
+			return -EINVAL;
+		}
+
+		var = btf_var(t_var);
+		if (var->linkage == BTF_VAR_STATIC || var->linkage == BTF_VAR_GLOBAL_EXTERN)
+			continue;
+
+		var_name = btf__name_by_offset(btf, t_var->name_off);
+		if (!var_name) {
+			pr_debug("sec '%s': failed to find name of DATASEC's member #%u\n",
+				 sec_name, i);
+			return -ENOENT;
+		}
+
+		sym = find_elf_var_sym(obj, var_name);
+		if (IS_ERR(sym)) {
+			pr_debug("sec '%s': failed to find ELF symbol for VAR '%s'\n",
+				 sec_name, var_name);
+			return -ENOENT;
+		}
+
+		if (fixup_offsets)
+			vsi->offset = sym->st_value;
+
+		/* if variable is a global/weak symbol, but has restricted
+		 * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF VAR
+		 * as static. This follows similar logic for functions (BPF
+		 * subprogs) and influences libbpf's further decisions about
+		 * whether to make global data BPF array maps as
+		 * BPF_F_MMAPABLE.
+		 */
+		if (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN
+		    || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL)
+			var->linkage = BTF_VAR_STATIC;
+	}
+
+sort_vars:
+	qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off);
+	return 0;
+}
+
+static int bpf_object_fixup_btf(struct bpf_object *obj)
+{
+	int i, n, err = 0;
+
+	if (!obj->btf)
+		return 0;
+
+	n = btf__type_cnt(obj->btf);
+	for (i = 1; i < n; i++) {
+		struct btf_type *t = btf_type_by_id(obj->btf, i);
+
+		/* Loader needs to fix up some of the things compiler
+		 * couldn't get its hands on while emitting BTF. This
+		 * is section size and global variable offset. We use
+		 * the info from the ELF itself for this purpose.
+		 */
+		if (btf_is_datasec(t)) {
+			err = btf_fixup_datasec(obj, obj->btf, t);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+static bool prog_needs_vmlinux_btf(struct bpf_program *prog)
+{
+	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
+	    prog->type == BPF_PROG_TYPE_LSM)
+		return true;
+
+	/* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
+	 * also need vmlinux BTF
+	 */
+	if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
+		return true;
+
+	return false;
+}
+
+static bool map_needs_vmlinux_btf(struct bpf_map *map)
+{
+	return bpf_map__is_struct_ops(map);
+}
+
+static bool obj_needs_vmlinux_btf(const struct bpf_object *obj)
+{
+	struct bpf_program *prog;
+	struct bpf_map *map;
+	int i;
+
+	/* CO-RE relocations need kernel BTF, only when btf_custom_path
+	 * is not specified
+	 */
+	if (obj->btf_ext && obj->btf_ext->core_relo_info.len && !obj->btf_custom_path)
+		return true;
+
+	/* Support for typed ksyms needs kernel BTF */
+	for (i = 0; i < obj->nr_extern; i++) {
+		const struct extern_desc *ext;
+
+		ext = &obj->externs[i];
+		if (ext->type == EXT_KSYM && ext->ksym.type_id)
+			return true;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		if (!prog->autoload)
+			continue;
+		if (prog_needs_vmlinux_btf(prog))
+			return true;
+	}
+
+	bpf_object__for_each_map(map, obj) {
+		if (map_needs_vmlinux_btf(map))
+			return true;
+	}
+
+	return false;
+}
+
+static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force)
+{
+	int err;
+
+	/* btf_vmlinux could be loaded earlier */
+	if (obj->btf_vmlinux || obj->gen_loader)
+		return 0;
+
+	if (!force && !obj_needs_vmlinux_btf(obj))
+		return 0;
+
+	obj->btf_vmlinux = btf__load_vmlinux_btf();
+	err = libbpf_get_error(obj->btf_vmlinux);
+	if (err) {
+		pr_warn("Error loading vmlinux BTF: %s\n", errstr(err));
+		obj->btf_vmlinux = NULL;
+		return err;
+	}
+	return 0;
+}
+
+static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
+{
+	struct btf *kern_btf = obj->btf;
+	bool btf_mandatory, sanitize;
+	int i, err = 0;
+
+	if (!obj->btf)
+		return 0;
+
+	if (!kernel_supports(obj, FEAT_BTF)) {
+		if (kernel_needs_btf(obj)) {
+			err = -EOPNOTSUPP;
+			goto report;
+		}
+		pr_debug("Kernel doesn't support BTF, skipping uploading it.\n");
+		return 0;
+	}
+
+	/* Even though some subprogs are global/weak, user might prefer more
+	 * permissive BPF verification process that BPF verifier performs for
+	 * static functions, taking into account more context from the caller
+	 * functions. In such case, they need to mark such subprogs with
+	 * __attribute__((visibility("hidden"))) and libbpf will adjust
+	 * corresponding FUNC BTF type to be marked as static and trigger more
+	 * involved BPF verification process.
+	 */
+	for (i = 0; i < obj->nr_programs; i++) {
+		struct bpf_program *prog = &obj->programs[i];
+		struct btf_type *t;
+		const char *name;
+		int j, n;
+
+		if (!prog->mark_btf_static || !prog_is_subprog(obj, prog))
+			continue;
+
+		n = btf__type_cnt(obj->btf);
+		for (j = 1; j < n; j++) {
+			t = btf_type_by_id(obj->btf, j);
+			if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL)
+				continue;
+
+			name = btf__str_by_offset(obj->btf, t->name_off);
+			if (strcmp(name, prog->name) != 0)
+				continue;
+
+			t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_STATIC, 0);
+			break;
+		}
+	}
+
+	sanitize = btf_needs_sanitization(obj);
+	if (sanitize) {
+		kern_btf = bpf_object__sanitize_btf(obj, obj->btf);
+		if (IS_ERR(kern_btf))
+			return PTR_ERR(kern_btf);
+	}
+
+	if (obj->gen_loader) {
+		__u32 raw_size = 0;
+		const void *raw_data = btf__raw_data(kern_btf, &raw_size);
+
+		if (!raw_data)
+			return -ENOMEM;
+		bpf_gen__load_btf(obj->gen_loader, raw_data, raw_size);
+		/* Pretend to have valid FD to pass various fd >= 0 checks.
+		 * This fd == 0 will not be used with any syscall and will be reset to -1 eventually.
+		 */
+		btf__set_fd(kern_btf, 0);
+	} else {
+		/* currently BPF_BTF_LOAD only supports log_level 1 */
+		err = btf_load_into_kernel(kern_btf, obj->log_buf, obj->log_size,
+					   obj->log_level ? 1 : 0, obj->token_fd);
+	}
+	if (sanitize) {
+		if (!err) {
+			/* move fd to libbpf's BTF */
+			btf__set_fd(obj->btf, btf__fd(kern_btf));
+			btf__set_fd(kern_btf, -1);
+		}
+		btf__free(kern_btf);
+	}
+report:
+	if (err) {
+		btf_mandatory = kernel_needs_btf(obj);
+		if (btf_mandatory) {
+			pr_warn("Error loading .BTF into kernel: %s. BTF is mandatory, can't proceed.\n",
+				errstr(err));
+		} else {
+			pr_info("Error loading .BTF into kernel: %s. BTF is optional, ignoring.\n",
+				errstr(err));
+			err = 0;
+		}
+	}
+	return err;
+}
+
+static const char *elf_sym_str(const struct bpf_object *obj, size_t off)
+{
+	const char *name;
+
+	name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, off);
+	if (!name) {
+		pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n",
+			off, obj->path, elf_errmsg(-1));
+		return NULL;
+	}
+
+	return name;
+}
+
+static const char *elf_sec_str(const struct bpf_object *obj, size_t off)
+{
+	const char *name;
+
+	name = elf_strptr(obj->efile.elf, obj->efile.shstrndx, off);
+	if (!name) {
+		pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n",
+			off, obj->path, elf_errmsg(-1));
+		return NULL;
+	}
+
+	return name;
+}
+
+static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx)
+{
+	Elf_Scn *scn;
+
+	scn = elf_getscn(obj->efile.elf, idx);
+	if (!scn) {
+		pr_warn("elf: failed to get section(%zu) from %s: %s\n",
+			idx, obj->path, elf_errmsg(-1));
+		return NULL;
+	}
+	return scn;
+}
+
+static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name)
+{
+	Elf_Scn *scn = NULL;
+	Elf *elf = obj->efile.elf;
+	const char *sec_name;
+
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		sec_name = elf_sec_name(obj, scn);
+		if (!sec_name)
+			return NULL;
+
+		if (strcmp(sec_name, name) != 0)
+			continue;
+
+		return scn;
+	}
+	return NULL;
+}
+
+static Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn)
+{
+	Elf64_Shdr *shdr;
+
+	if (!scn)
+		return NULL;
+
+	shdr = elf64_getshdr(scn);
+	if (!shdr) {
+		pr_warn("elf: failed to get section(%zu) header from %s: %s\n",
+			elf_ndxscn(scn), obj->path, elf_errmsg(-1));
+		return NULL;
+	}
+
+	return shdr;
+}
+
+static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn)
+{
+	const char *name;
+	Elf64_Shdr *sh;
+
+	if (!scn)
+		return NULL;
+
+	sh = elf_sec_hdr(obj, scn);
+	if (!sh)
+		return NULL;
+
+	name = elf_sec_str(obj, sh->sh_name);
+	if (!name) {
+		pr_warn("elf: failed to get section(%zu) name from %s: %s\n",
+			elf_ndxscn(scn), obj->path, elf_errmsg(-1));
+		return NULL;
+	}
+
+	return name;
+}
+
+static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn)
+{
+	Elf_Data *data;
+
+	if (!scn)
+		return NULL;
+
+	data = elf_getdata(scn, 0);
+	if (!data) {
+		pr_warn("elf: failed to get section(%zu) %s data from %s: %s\n",
+			elf_ndxscn(scn), elf_sec_name(obj, scn) ?: "<?>",
+			obj->path, elf_errmsg(-1));
+		return NULL;
+	}
+
+	return data;
+}
+
+static Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx)
+{
+	if (idx >= obj->efile.symbols->d_size / sizeof(Elf64_Sym))
+		return NULL;
+
+	return (Elf64_Sym *)obj->efile.symbols->d_buf + idx;
+}
+
+static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx)
+{
+	if (idx >= data->d_size / sizeof(Elf64_Rel))
+		return NULL;
+
+	return (Elf64_Rel *)data->d_buf + idx;
+}
+
+static bool is_sec_name_dwarf(const char *name)
+{
+	/* approximation, but the actual list is too long */
+	return str_has_pfx(name, ".debug_");
+}
+
+static bool ignore_elf_section(Elf64_Shdr *hdr, const char *name)
+{
+	/* no special handling of .strtab */
+	if (hdr->sh_type == SHT_STRTAB)
+		return true;
+
+	/* ignore .llvm_addrsig section as well */
+	if (hdr->sh_type == SHT_LLVM_ADDRSIG)
+		return true;
+
+	/* no subprograms will lead to an empty .text section, ignore it */
+	if (hdr->sh_type == SHT_PROGBITS && hdr->sh_size == 0 &&
+	    strcmp(name, ".text") == 0)
+		return true;
+
+	/* DWARF sections */
+	if (is_sec_name_dwarf(name))
+		return true;
+
+	if (str_has_pfx(name, ".rel")) {
+		name += sizeof(".rel") - 1;
+		/* DWARF section relocations */
+		if (is_sec_name_dwarf(name))
+			return true;
+
+		/* .BTF and .BTF.ext don't need relocations */
+		if (strcmp(name, BTF_ELF_SEC) == 0 ||
+		    strcmp(name, BTF_EXT_ELF_SEC) == 0)
+			return true;
+	}
+
+	return false;
+}
+
+static int cmp_progs(const void *_a, const void *_b)
+{
+	const struct bpf_program *a = _a;
+	const struct bpf_program *b = _b;
+
+	if (a->sec_idx != b->sec_idx)
+		return a->sec_idx < b->sec_idx ? -1 : 1;
+
+	/* sec_insn_off can't be the same within the section */
+	return a->sec_insn_off < b->sec_insn_off ? -1 : 1;
+}
+
+static int bpf_object__elf_collect(struct bpf_object *obj)
+{
+	struct elf_sec_desc *sec_desc;
+	Elf *elf = obj->efile.elf;
+	Elf_Data *btf_ext_data = NULL;
+	Elf_Data *btf_data = NULL;
+	int idx = 0, err = 0;
+	const char *name;
+	Elf_Data *data;
+	Elf_Scn *scn;
+	Elf64_Shdr *sh;
+
+	/* ELF section indices are 0-based, but sec #0 is special "invalid"
+	 * section. Since section count retrieved by elf_getshdrnum() does
+	 * include sec #0, it is already the necessary size of an array to keep
+	 * all the sections.
+	 */
+	if (elf_getshdrnum(obj->efile.elf, &obj->efile.sec_cnt)) {
+		pr_warn("elf: failed to get the number of sections for %s: %s\n",
+			obj->path, elf_errmsg(-1));
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+	obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs));
+	if (!obj->efile.secs)
+		return -ENOMEM;
+
+	/* a bunch of ELF parsing functionality depends on processing symbols,
+	 * so do the first pass and find the symbol table
+	 */
+	scn = NULL;
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		sh = elf_sec_hdr(obj, scn);
+		if (!sh)
+			return -LIBBPF_ERRNO__FORMAT;
+
+		if (sh->sh_type == SHT_SYMTAB) {
+			if (obj->efile.symbols) {
+				pr_warn("elf: multiple symbol tables in %s\n", obj->path);
+				return -LIBBPF_ERRNO__FORMAT;
+			}
+
+			data = elf_sec_data(obj, scn);
+			if (!data)
+				return -LIBBPF_ERRNO__FORMAT;
+
+			idx = elf_ndxscn(scn);
+
+			obj->efile.symbols = data;
+			obj->efile.symbols_shndx = idx;
+			obj->efile.strtabidx = sh->sh_link;
+		}
+	}
+
+	if (!obj->efile.symbols) {
+		pr_warn("elf: couldn't find symbol table in %s, stripped object file?\n",
+			obj->path);
+		return -ENOENT;
+	}
+
+	scn = NULL;
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		idx = elf_ndxscn(scn);
+		sec_desc = &obj->efile.secs[idx];
+
+		sh = elf_sec_hdr(obj, scn);
+		if (!sh)
+			return -LIBBPF_ERRNO__FORMAT;
+
+		name = elf_sec_str(obj, sh->sh_name);
+		if (!name)
+			return -LIBBPF_ERRNO__FORMAT;
+
+		if (ignore_elf_section(sh, name))
+			continue;
+
+		data = elf_sec_data(obj, scn);
+		if (!data)
+			return -LIBBPF_ERRNO__FORMAT;
+
+		pr_debug("elf: section(%d) %s, size %lu, link %d, flags %lx, type=%d\n",
+			 idx, name, (unsigned long)data->d_size,
+			 (int)sh->sh_link, (unsigned long)sh->sh_flags,
+			 (int)sh->sh_type);
+
+		if (strcmp(name, "license") == 0) {
+			err = bpf_object__init_license(obj, data->d_buf, data->d_size);
+			if (err)
+				return err;
+		} else if (strcmp(name, "version") == 0) {
+			err = bpf_object__init_kversion(obj, data->d_buf, data->d_size);
+			if (err)
+				return err;
+		} else if (strcmp(name, "maps") == 0) {
+			pr_warn("elf: legacy map definitions in 'maps' section are not supported by libbpf v1.0+\n");
+			return -ENOTSUP;
+		} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
+			obj->efile.btf_maps_shndx = idx;
+		} else if (strcmp(name, BTF_ELF_SEC) == 0) {
+			if (sh->sh_type != SHT_PROGBITS)
+				return -LIBBPF_ERRNO__FORMAT;
+			btf_data = data;
+		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
+			if (sh->sh_type != SHT_PROGBITS)
+				return -LIBBPF_ERRNO__FORMAT;
+			btf_ext_data = data;
+		} else if (sh->sh_type == SHT_SYMTAB) {
+			/* already processed during the first pass above */
+		} else if (sh->sh_type == SHT_PROGBITS && data->d_size > 0) {
+			if (sh->sh_flags & SHF_EXECINSTR) {
+				if (strcmp(name, ".text") == 0)
+					obj->efile.text_shndx = idx;
+				err = bpf_object__add_programs(obj, data, name, idx);
+				if (err)
+					return err;
+			} else if (strcmp(name, DATA_SEC) == 0 ||
+				   str_has_pfx(name, DATA_SEC ".")) {
+				sec_desc->sec_type = SEC_DATA;
+				sec_desc->shdr = sh;
+				sec_desc->data = data;
+			} else if (strcmp(name, RODATA_SEC) == 0 ||
+				   str_has_pfx(name, RODATA_SEC ".")) {
+				sec_desc->sec_type = SEC_RODATA;
+				sec_desc->shdr = sh;
+				sec_desc->data = data;
+			} else if (strcmp(name, PERCPU_SEC) == 0 ||
+				   str_has_pfx(name, PERCPU_SEC ".")) {
+				sec_desc->sec_type = SEC_PERCPU;
+				sec_desc->shdr = sh;
+				sec_desc->data = data;
+			} else if (strcmp(name, STRUCT_OPS_SEC) == 0 ||
+				   strcmp(name, STRUCT_OPS_LINK_SEC) == 0 ||
+				   strcmp(name, "?" STRUCT_OPS_SEC) == 0 ||
+				   strcmp(name, "?" STRUCT_OPS_LINK_SEC) == 0) {
+				sec_desc->sec_type = SEC_ST_OPS;
+				sec_desc->shdr = sh;
+				sec_desc->data = data;
+				obj->efile.has_st_ops = true;
+			} else if (strcmp(name, ARENA_SEC) == 0) {
+				obj->efile.arena_data = data;
+				obj->efile.arena_data_shndx = idx;
+			} else if (strcmp(name, JUMPTABLES_SEC) == 0) {
+				obj->jumptables_data = malloc(data->d_size);
+				if (!obj->jumptables_data)
+					return -ENOMEM;
+				memcpy(obj->jumptables_data, data->d_buf, data->d_size);
+				obj->jumptables_data_sz = data->d_size;
+				obj->efile.jumptables_data_shndx = idx;
+			} else {
+				pr_info("elf: skipping unrecognized data section(%d) %s\n",
+					idx, name);
+			}
+		} else if (sh->sh_type == SHT_REL) {
+			int targ_sec_idx = sh->sh_info; /* points to other section */
+
+			if (sh->sh_entsize != sizeof(Elf64_Rel) ||
+			    targ_sec_idx >= obj->efile.sec_cnt)
+				return -LIBBPF_ERRNO__FORMAT;
+
+			/* Only do relo for section with exec instructions */
+			if (!section_have_execinstr(obj, targ_sec_idx) &&
+			    strcmp(name, ".rel" STRUCT_OPS_SEC) &&
+			    strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) &&
+			    strcmp(name, ".rel?" STRUCT_OPS_SEC) &&
+			    strcmp(name, ".rel?" STRUCT_OPS_LINK_SEC) &&
+			    strcmp(name, ".rel" MAPS_ELF_SEC)) {
+				pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n",
+					idx, name, targ_sec_idx,
+					elf_sec_name(obj, elf_sec_by_idx(obj, targ_sec_idx)) ?: "<?>");
+				continue;
+			}
+
+			sec_desc->sec_type = SEC_RELO;
+			sec_desc->shdr = sh;
+			sec_desc->data = data;
+		} else if (sh->sh_type == SHT_NOBITS && (strcmp(name, BSS_SEC) == 0 ||
+							 str_has_pfx(name, BSS_SEC "."))) {
+			sec_desc->sec_type = SEC_BSS;
+			sec_desc->shdr = sh;
+			sec_desc->data = data;
+		} else {
+			pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name,
+				(size_t)sh->sh_size);
+		}
+	}
+
+	if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
+		pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path);
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+
+	/* change BPF program insns to native endianness for introspection */
+	if (!is_native_endianness(obj))
+		bpf_object_bswap_progs(obj);
+
+	/* sort BPF programs by section name and in-section instruction offset
+	 * for faster search
+	 */
+	if (obj->nr_programs)
+		qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs);
+
+	return bpf_object__init_btf(obj, btf_data, btf_ext_data);
+}
+
+static bool sym_is_extern(const Elf64_Sym *sym)
+{
+	int bind = ELF64_ST_BIND(sym->st_info);
+	/* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */
+	return sym->st_shndx == SHN_UNDEF &&
+	       (bind == STB_GLOBAL || bind == STB_WEAK) &&
+	       ELF64_ST_TYPE(sym->st_info) == STT_NOTYPE;
+}
+
+static bool sym_is_subprog(const Elf64_Sym *sym, int text_shndx)
+{
+	int bind = ELF64_ST_BIND(sym->st_info);
+	int type = ELF64_ST_TYPE(sym->st_info);
+
+	/* in .text section */
+	if (sym->st_shndx != text_shndx)
+		return false;
+
+	/* local function */
+	if (bind == STB_LOCAL && type == STT_SECTION)
+		return true;
+
+	/* global function */
+	return (bind == STB_GLOBAL || bind == STB_WEAK) && type == STT_FUNC;
+}
+
+static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
+{
+	const struct btf_type *t;
+	const char *tname;
+	int i, n;
+
+	if (!btf)
+		return -ESRCH;
+
+	n = btf__type_cnt(btf);
+	for (i = 1; i < n; i++) {
+		t = btf__type_by_id(btf, i);
+
+		if (!btf_is_var(t) && !btf_is_func(t))
+			continue;
+
+		tname = btf__name_by_offset(btf, t->name_off);
+		if (strcmp(tname, ext_name))
+			continue;
+
+		if (btf_is_var(t) &&
+		    btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
+			return -EINVAL;
+
+		if (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_EXTERN)
+			return -EINVAL;
+
+		return i;
+	}
+
+	return -ENOENT;
+}
+
+static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) {
+	const struct btf_var_secinfo *vs;
+	const struct btf_type *t;
+	int i, j, n;
+
+	if (!btf)
+		return -ESRCH;
+
+	n = btf__type_cnt(btf);
+	for (i = 1; i < n; i++) {
+		t = btf__type_by_id(btf, i);
+
+		if (!btf_is_datasec(t))
+			continue;
+
+		vs = btf_var_secinfos(t);
+		for (j = 0; j < btf_vlen(t); j++, vs++) {
+			if (vs->type == ext_btf_id)
+				return i;
+		}
+	}
+
+	return -ENOENT;
+}
+
+static enum kcfg_type find_kcfg_type(const struct btf *btf, int id,
+				     bool *is_signed)
+{
+	const struct btf_type *t;
+	const char *name;
+
+	t = skip_mods_and_typedefs(btf, id, NULL);
+	name = btf__name_by_offset(btf, t->name_off);
+
+	if (is_signed)
+		*is_signed = false;
+	switch (btf_kind(t)) {
+	case BTF_KIND_INT: {
+		int enc = btf_int_encoding(t);
+
+		if (enc & BTF_INT_BOOL)
+			return t->size == 1 ? KCFG_BOOL : KCFG_UNKNOWN;
+		if (is_signed)
+			*is_signed = enc & BTF_INT_SIGNED;
+		if (t->size == 1)
+			return KCFG_CHAR;
+		if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1)))
+			return KCFG_UNKNOWN;
+		return KCFG_INT;
+	}
+	case BTF_KIND_ENUM:
+		if (t->size != 4)
+			return KCFG_UNKNOWN;
+		if (strcmp(name, "libbpf_tristate"))
+			return KCFG_UNKNOWN;
+		return KCFG_TRISTATE;
+	case BTF_KIND_ENUM64:
+		if (strcmp(name, "libbpf_tristate"))
+			return KCFG_UNKNOWN;
+		return KCFG_TRISTATE;
+	case BTF_KIND_ARRAY:
+		if (btf_array(t)->nelems == 0)
+			return KCFG_UNKNOWN;
+		if (find_kcfg_type(btf, btf_array(t)->type, NULL) != KCFG_CHAR)
+			return KCFG_UNKNOWN;
+		return KCFG_CHAR_ARR;
+	default:
+		return KCFG_UNKNOWN;
+	}
+}
+
+static int cmp_externs(const void *_a, const void *_b)
+{
+	const struct extern_desc *a = _a;
+	const struct extern_desc *b = _b;
+
+	if (a->type != b->type)
+		return a->type < b->type ? -1 : 1;
+
+	if (a->type == EXT_KCFG) {
+		/* descending order by alignment requirements */
+		if (a->kcfg.align != b->kcfg.align)
+			return a->kcfg.align > b->kcfg.align ? -1 : 1;
+		/* ascending order by size, within same alignment class */
+		if (a->kcfg.sz != b->kcfg.sz)
+			return a->kcfg.sz < b->kcfg.sz ? -1 : 1;
+	}
+
+	/* resolve ties by name */
+	return strcmp(a->name, b->name);
+}
+
+static int find_int_btf_id(const struct btf *btf)
+{
+	const struct btf_type *t;
+	int i, n;
+
+	n = btf__type_cnt(btf);
+	for (i = 1; i < n; i++) {
+		t = btf__type_by_id(btf, i);
+
+		if (btf_is_int(t) && btf_int_bits(t) == 32)
+			return i;
+	}
+
+	return 0;
+}
+
+static int add_dummy_ksym_var(struct btf *btf)
+{
+	int i, int_btf_id, sec_btf_id, dummy_var_btf_id;
+	const struct btf_var_secinfo *vs;
+	const struct btf_type *sec;
+
+	if (!btf)
+		return 0;
+
+	sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC,
+					    BTF_KIND_DATASEC);
+	if (sec_btf_id < 0)
+		return 0;
+
+	sec = btf__type_by_id(btf, sec_btf_id);
+	vs = btf_var_secinfos(sec);
+	for (i = 0; i < btf_vlen(sec); i++, vs++) {
+		const struct btf_type *vt;
+
+		vt = btf__type_by_id(btf, vs->type);
+		if (btf_is_func(vt))
+			break;
+	}
+
+	/* No func in ksyms sec.  No need to add dummy var. */
+	if (i == btf_vlen(sec))
+		return 0;
+
+	int_btf_id = find_int_btf_id(btf);
+	dummy_var_btf_id = btf__add_var(btf,
+					"dummy_ksym",
+					BTF_VAR_GLOBAL_ALLOCATED,
+					int_btf_id);
+	if (dummy_var_btf_id < 0)
+		pr_warn("cannot create a dummy_ksym var\n");
+
+	return dummy_var_btf_id;
+}
+
+static int bpf_object__collect_externs(struct bpf_object *obj)
+{
+	struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL;
+	const struct btf_type *t;
+	struct extern_desc *ext;
+	int i, n, off, dummy_var_btf_id;
+	const char *ext_name, *sec_name;
+	size_t ext_essent_len;
+	Elf_Scn *scn;
+	Elf64_Shdr *sh;
+
+	if (!obj->efile.symbols)
+		return 0;
+
+	scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx);
+	sh = elf_sec_hdr(obj, scn);
+	if (!sh || sh->sh_entsize != sizeof(Elf64_Sym))
+		return -LIBBPF_ERRNO__FORMAT;
+
+	dummy_var_btf_id = add_dummy_ksym_var(obj->btf);
+	if (dummy_var_btf_id < 0)
+		return dummy_var_btf_id;
+
+	n = sh->sh_size / sh->sh_entsize;
+	pr_debug("looking for externs among %d symbols...\n", n);
+
+	for (i = 0; i < n; i++) {
+		Elf64_Sym *sym = elf_sym_by_idx(obj, i);
+
+		if (!sym)
+			return -LIBBPF_ERRNO__FORMAT;
+		if (!sym_is_extern(sym))
+			continue;
+		ext_name = elf_sym_str(obj, sym->st_name);
+		if (str_is_empty(ext_name))
+			continue;
+
+		ext = obj->externs;
+		ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
+		if (!ext)
+			return -ENOMEM;
+		obj->externs = ext;
+		ext = &ext[obj->nr_extern];
+		memset(ext, 0, sizeof(*ext));
+		obj->nr_extern++;
+
+		ext->btf_id = find_extern_btf_id(obj->btf, ext_name);
+		if (ext->btf_id <= 0) {
+			pr_warn("failed to find BTF for extern '%s': %d\n",
+				ext_name, ext->btf_id);
+			return ext->btf_id;
+		}
+		t = btf__type_by_id(obj->btf, ext->btf_id);
+		ext->name = strdup(btf__name_by_offset(obj->btf, t->name_off));
+		if (!ext->name)
+			return -ENOMEM;
+		ext->sym_idx = i;
+		ext->is_weak = ELF64_ST_BIND(sym->st_info) == STB_WEAK;
+
+		ext_essent_len = bpf_core_essential_name_len(ext->name);
+		ext->essent_name = NULL;
+		if (ext_essent_len != strlen(ext->name)) {
+			ext->essent_name = strndup(ext->name, ext_essent_len);
+			if (!ext->essent_name)
+				return -ENOMEM;
+		}
+
+		ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id);
+		if (ext->sec_btf_id <= 0) {
+			pr_warn("failed to find BTF for extern '%s' [%d] section: %d\n",
+				ext_name, ext->btf_id, ext->sec_btf_id);
+			return ext->sec_btf_id;
+		}
+		sec = (void *)btf__type_by_id(obj->btf, ext->sec_btf_id);
+		sec_name = btf__name_by_offset(obj->btf, sec->name_off);
+
+		if (strcmp(sec_name, KCONFIG_SEC) == 0) {
+			if (btf_is_func(t)) {
+				pr_warn("extern function %s is unsupported under %s section\n",
+					ext->name, KCONFIG_SEC);
+				return -ENOTSUP;
+			}
+			kcfg_sec = sec;
+			ext->type = EXT_KCFG;
+			ext->kcfg.sz = btf__resolve_size(obj->btf, t->type);
+			if (ext->kcfg.sz <= 0) {
+				pr_warn("failed to resolve size of extern (kcfg) '%s': %d\n",
+					ext_name, ext->kcfg.sz);
+				return ext->kcfg.sz;
+			}
+			ext->kcfg.align = btf__align_of(obj->btf, t->type);
+			if (ext->kcfg.align <= 0) {
+				pr_warn("failed to determine alignment of extern (kcfg) '%s': %d\n",
+					ext_name, ext->kcfg.align);
+				return -EINVAL;
+			}
+			ext->kcfg.type = find_kcfg_type(obj->btf, t->type,
+							&ext->kcfg.is_signed);
+			if (ext->kcfg.type == KCFG_UNKNOWN) {
+				pr_warn("extern (kcfg) '%s': type is unsupported\n", ext_name);
+				return -ENOTSUP;
+			}
+		} else if (strcmp(sec_name, KSYMS_SEC) == 0) {
+			ksym_sec = sec;
+			ext->type = EXT_KSYM;
+			skip_mods_and_typedefs(obj->btf, t->type,
+					       &ext->ksym.type_id);
+		} else {
+			pr_warn("unrecognized extern section '%s'\n", sec_name);
+			return -ENOTSUP;
+		}
+	}
+	pr_debug("collected %d externs total\n", obj->nr_extern);
+
+	if (!obj->nr_extern)
+		return 0;
+
+	/* sort externs by type, for kcfg ones also by (align, size, name) */
+	qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs);
+
+	/* for .ksyms section, we need to turn all externs into allocated
+	 * variables in BTF to pass kernel verification; we do this by
+	 * pretending that each extern is a 8-byte variable
+	 */
+	if (ksym_sec) {
+		/* find existing 4-byte integer type in BTF to use for fake
+		 * extern variables in DATASEC
+		 */
+		int int_btf_id = find_int_btf_id(obj->btf);
+		/* For extern function, a dummy_var added earlier
+		 * will be used to replace the vs->type and
+		 * its name string will be used to refill
+		 * the missing param's name.
+		 */
+		const struct btf_type *dummy_var;
+
+		dummy_var = btf__type_by_id(obj->btf, dummy_var_btf_id);
+		for (i = 0; i < obj->nr_extern; i++) {
+			ext = &obj->externs[i];
+			if (ext->type != EXT_KSYM)
+				continue;
+			pr_debug("extern (ksym) #%d: symbol %d, name %s\n",
+				 i, ext->sym_idx, ext->name);
+		}
+
+		sec = ksym_sec;
+		n = btf_vlen(sec);
+		for (i = 0, off = 0; i < n; i++, off += sizeof(int)) {
+			struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
+			struct btf_type *vt;
+
+			vt = (void *)btf__type_by_id(obj->btf, vs->type);
+			ext_name = btf__name_by_offset(obj->btf, vt->name_off);
+			ext = find_extern_by_name(obj, ext_name);
+			if (!ext) {
+				pr_warn("failed to find extern definition for BTF %s '%s'\n",
+					btf_kind_str(vt), ext_name);
+				return -ESRCH;
+			}
+			if (btf_is_func(vt)) {
+				const struct btf_type *func_proto;
+				struct btf_param *param;
+				int j;
+
+				func_proto = btf__type_by_id(obj->btf,
+							     vt->type);
+				param = btf_params(func_proto);
+				/* Reuse the dummy_var string if the
+				 * func proto does not have param name.
+				 */
+				for (j = 0; j < btf_vlen(func_proto); j++)
+					if (param[j].type && !param[j].name_off)
+						param[j].name_off =
+							dummy_var->name_off;
+				vs->type = dummy_var_btf_id;
+				vt->info &= ~0xffff;
+				vt->info |= BTF_FUNC_GLOBAL;
+			} else {
+				btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
+				vt->type = int_btf_id;
+			}
+			vs->offset = off;
+			vs->size = sizeof(int);
+		}
+		sec->size = off;
+	}
+
+	if (kcfg_sec) {
+		sec = kcfg_sec;
+		/* for kcfg externs calculate their offsets within a .kconfig map */
+		off = 0;
+		for (i = 0; i < obj->nr_extern; i++) {
+			ext = &obj->externs[i];
+			if (ext->type != EXT_KCFG)
+				continue;
+
+			ext->kcfg.data_off = roundup(off, ext->kcfg.align);
+			off = ext->kcfg.data_off + ext->kcfg.sz;
+			pr_debug("extern (kcfg) #%d: symbol %d, off %d, name %s\n",
+				 i, ext->sym_idx, ext->kcfg.data_off, ext->name);
+		}
+		sec->size = off;
+		n = btf_vlen(sec);
+		for (i = 0; i < n; i++) {
+			struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
+
+			t = btf__type_by_id(obj->btf, vs->type);
+			ext_name = btf__name_by_offset(obj->btf, t->name_off);
+			ext = find_extern_by_name(obj, ext_name);
+			if (!ext) {
+				pr_warn("failed to find extern definition for BTF var '%s'\n",
+					ext_name);
+				return -ESRCH;
+			}
+			btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
+			vs->offset = ext->kcfg.data_off;
+		}
+	}
+	return 0;
+}
+
+static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog)
+{
+	return prog->sec_idx == obj->efile.text_shndx;
+}
+
+struct bpf_program *
+bpf_object__find_program_by_name(const struct bpf_object *obj,
+				 const char *name)
+{
+	struct bpf_program *prog;
+
+	bpf_object__for_each_program(prog, obj) {
+		if (prog_is_subprog(obj, prog))
+			continue;
+		if (!strcmp(prog->name, name))
+			return prog;
+	}
+	return errno = ENOENT, NULL;
+}
+
+static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
+				      int shndx)
+{
+	switch (obj->efile.secs[shndx].sec_type) {
+	case SEC_BSS:
+	case SEC_DATA:
+	case SEC_RODATA:
+	case SEC_PERCPU:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
+				      int shndx)
+{
+	return shndx == obj->efile.btf_maps_shndx;
+}
+
+static enum libbpf_map_type
+bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
+{
+	if (shndx == obj->efile.symbols_shndx)
+		return LIBBPF_MAP_KCONFIG;
+
+	switch (obj->efile.secs[shndx].sec_type) {
+	case SEC_BSS:
+		return LIBBPF_MAP_BSS;
+	case SEC_DATA:
+		return LIBBPF_MAP_DATA;
+	case SEC_RODATA:
+		return LIBBPF_MAP_RODATA;
+	case SEC_PERCPU:
+		return LIBBPF_MAP_PERCPU;
+	default:
+		return LIBBPF_MAP_UNSPEC;
+	}
+}
+
+static int bpf_prog_compute_hash(struct bpf_program *prog)
+{
+	struct bpf_insn *purged;
+	int i, err = 0;
+
+	purged = calloc(prog->insns_cnt, BPF_INSN_SZ);
+	if (!purged)
+		return -ENOMEM;
+
+	/* If relocations have been done, the map_fd needs to be
+	 * discarded for the digest calculation.
+	 */
+	for (i = 0; i < prog->insns_cnt; i++) {
+		purged[i] = prog->insns[i];
+		if (purged[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
+		    (purged[i].src_reg == BPF_PSEUDO_MAP_FD ||
+		     purged[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
+			purged[i].imm = 0;
+			i++;
+			if (i >= prog->insns_cnt ||
+			    prog->insns[i].code != 0 ||
+			    prog->insns[i].dst_reg != 0 ||
+			    prog->insns[i].src_reg != 0 ||
+			    prog->insns[i].off != 0) {
+				err = -EINVAL;
+				goto out;
+			}
+			purged[i] = prog->insns[i];
+			purged[i].imm = 0;
+		}
+	}
+	libbpf_sha256(purged, prog->insns_cnt * sizeof(struct bpf_insn),
+		      prog->hash);
+out:
+	free(purged);
+	return err;
+}
+
+static int bpf_program__record_reloc(struct bpf_program *prog,
+				     struct reloc_desc *reloc_desc,
+				     __u32 insn_idx, const char *sym_name,
+				     const Elf64_Sym *sym, const Elf64_Rel *rel)
+{
+	struct bpf_insn *insn = &prog->insns[insn_idx];
+	size_t map_idx, nr_maps = prog->obj->nr_maps;
+	struct bpf_object *obj = prog->obj;
+	__u32 shdr_idx = sym->st_shndx;
+	enum libbpf_map_type type;
+	const char *sym_sec_name;
+	struct bpf_map *map;
+
+	if (!is_call_insn(insn) && !is_ldimm64_insn(insn)) {
+		pr_warn("prog '%s': invalid relo against '%s' for insns[%u].code 0x%x\n",
+			prog->name, sym_name, insn_idx, insn->code);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+
+	if (sym_is_extern(sym)) {
+		int sym_idx = ELF64_R_SYM(rel->r_info);
+		int i, n = obj->nr_extern;
+		struct extern_desc *ext;
+
+		for (i = 0; i < n; i++) {
+			ext = &obj->externs[i];
+			if (ext->sym_idx == sym_idx)
+				break;
+		}
+		if (i >= n) {
+			pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n",
+				prog->name, sym_name, sym_idx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n",
+			 prog->name, i, ext->name, ext->sym_idx, insn_idx);
+		if (insn->code == (BPF_JMP | BPF_CALL))
+			reloc_desc->type = RELO_EXTERN_CALL;
+		else
+			reloc_desc->type = RELO_EXTERN_LD64;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->ext_idx = i;
+		return 0;
+	}
+
+	/* sub-program call relocation */
+	if (is_call_insn(insn)) {
+		if (insn->src_reg != BPF_PSEUDO_CALL) {
+			pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		/* text_shndx can be 0, if no default "main" program exists */
+		if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
+			sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
+			pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
+				prog->name, sym_name, sym_sec_name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		if (sym->st_value % BPF_INSN_SZ) {
+			pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
+				prog->name, sym_name, (size_t)sym->st_value);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		reloc_desc->type = RELO_CALL;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->sym_off = sym->st_value;
+		return 0;
+	}
+
+	if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
+		pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n",
+			prog->name, sym_name, shdr_idx);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+
+	/* loading subprog addresses */
+	if (sym_is_subprog(sym, obj->efile.text_shndx)) {
+		/* global_func: sym->st_value = offset in the section, insn->imm = 0.
+		 * local_func: sym->st_value = 0, insn->imm = offset in the section.
+		 */
+		if ((sym->st_value % BPF_INSN_SZ) || (insn->imm % BPF_INSN_SZ)) {
+			pr_warn("prog '%s': bad subprog addr relo against '%s' at offset %zu+%d\n",
+				prog->name, sym_name, (size_t)sym->st_value, insn->imm);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+
+		reloc_desc->type = RELO_SUBPROG_ADDR;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->sym_off = sym->st_value;
+		return 0;
+	}
+
+	type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
+	sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
+
+	/* arena data relocation */
+	if (shdr_idx == obj->efile.arena_data_shndx) {
+		if (obj->arena_map_idx < 0) {
+			pr_warn("prog '%s': bad arena data relocation at insn %u, no arena maps defined\n",
+				prog->name, insn_idx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		reloc_desc->type = RELO_DATA;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->map_idx = obj->arena_map_idx;
+		reloc_desc->sym_off = sym->st_value;
+
+		map = &obj->maps[obj->arena_map_idx];
+		pr_debug("prog '%s': found arena map %d (%s, sec %d, off %zu) for insn %u\n",
+			 prog->name, obj->arena_map_idx, map->name, map->sec_idx,
+			 map->sec_offset, insn_idx);
+		return 0;
+	}
+
+	/* jump table data relocation */
+	if (shdr_idx == obj->efile.jumptables_data_shndx) {
+		reloc_desc->type = RELO_INSN_ARRAY;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->map_idx = -1;
+		reloc_desc->sym_off = sym->st_value;
+		reloc_desc->sym_size = sym->st_size;
+		return 0;
+	}
+
+	/* generic map reference relocation */
+	if (type == LIBBPF_MAP_UNSPEC) {
+		if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
+			pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n",
+				prog->name, sym_name, sym_sec_name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+			map = &obj->maps[map_idx];
+			if (map->libbpf_type != type ||
+			    map->sec_idx != sym->st_shndx ||
+			    map->sec_offset != sym->st_value)
+				continue;
+			pr_debug("prog '%s': found map %zu (%s, sec %d, off %zu) for insn #%u\n",
+				 prog->name, map_idx, map->name, map->sec_idx,
+				 map->sec_offset, insn_idx);
+			break;
+		}
+		if (map_idx >= nr_maps) {
+			pr_warn("prog '%s': map relo failed to find map for section '%s', off %zu\n",
+				prog->name, sym_sec_name, (size_t)sym->st_value);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		reloc_desc->type = RELO_LD64;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->map_idx = map_idx;
+		reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */
+		return 0;
+	}
+
+	/* global data map relocation */
+	if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
+		pr_warn("prog '%s': bad data relo against section '%s'\n",
+			prog->name, sym_sec_name);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+	for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+		map = &obj->maps[map_idx];
+		if (map->libbpf_type != type || map->sec_idx != sym->st_shndx)
+			continue;
+		pr_debug("prog '%s': found data map %zu (%s, sec %d, off %zu) for insn %u\n",
+			 prog->name, map_idx, map->name, map->sec_idx,
+			 map->sec_offset, insn_idx);
+		break;
+	}
+	if (map_idx >= nr_maps) {
+		pr_warn("prog '%s': data relo failed to find map for section '%s'\n",
+			prog->name, sym_sec_name);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+
+	reloc_desc->type = RELO_DATA;
+	reloc_desc->insn_idx = insn_idx;
+	reloc_desc->map_idx = map_idx;
+	reloc_desc->sym_off = sym->st_value;
+	return 0;
+}
+
+static bool prog_contains_insn(const struct bpf_program *prog, size_t insn_idx)
+{
+	return insn_idx >= prog->sec_insn_off &&
+	       insn_idx < prog->sec_insn_off + prog->sec_insn_cnt;
+}
+
+static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj,
+						 size_t sec_idx, size_t insn_idx)
+{
+	int l = 0, r = obj->nr_programs - 1, m;
+	struct bpf_program *prog;
+
+	if (!obj->nr_programs)
+		return NULL;
+
+	while (l < r) {
+		m = l + (r - l + 1) / 2;
+		prog = &obj->programs[m];
+
+		if (prog->sec_idx < sec_idx ||
+		    (prog->sec_idx == sec_idx && prog->sec_insn_off <= insn_idx))
+			l = m;
+		else
+			r = m - 1;
+	}
+	/* matching program could be at index l, but it still might be the
+	 * wrong one, so we need to double check conditions for the last time
+	 */
+	prog = &obj->programs[l];
+	if (prog->sec_idx == sec_idx && prog_contains_insn(prog, insn_idx))
+		return prog;
+	return NULL;
+}
+
+static int
+bpf_object__collect_prog_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Data *data)
+{
+	const char *relo_sec_name, *sec_name;
+	size_t sec_idx = shdr->sh_info, sym_idx;
+	struct bpf_program *prog;
+	struct reloc_desc *relos;
+	int err, i, nrels;
+	const char *sym_name;
+	__u32 insn_idx;
+	Elf_Scn *scn;
+	Elf_Data *scn_data;
+	Elf64_Sym *sym;
+	Elf64_Rel *rel;
+
+	if (sec_idx >= obj->efile.sec_cnt)
+		return -EINVAL;
+
+	scn = elf_sec_by_idx(obj, sec_idx);
+	scn_data = elf_sec_data(obj, scn);
+	if (!scn_data)
+		return -LIBBPF_ERRNO__FORMAT;
+
+	relo_sec_name = elf_sec_str(obj, shdr->sh_name);
+	sec_name = elf_sec_name(obj, scn);
+	if (!relo_sec_name || !sec_name)
+		return -EINVAL;
+
+	pr_debug("sec '%s': collecting relocation for section(%zu) '%s'\n",
+		 relo_sec_name, sec_idx, sec_name);
+	nrels = shdr->sh_size / shdr->sh_entsize;
+
+	for (i = 0; i < nrels; i++) {
+		rel = elf_rel_by_idx(data, i);
+		if (!rel) {
+			pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		sym_idx = ELF64_R_SYM(rel->r_info);
+		sym = elf_sym_by_idx(obj, sym_idx);
+		if (!sym) {
+			pr_warn("sec '%s': symbol #%zu not found for relo #%d\n",
+				relo_sec_name, sym_idx, i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		if (sym->st_shndx >= obj->efile.sec_cnt) {
+			pr_warn("sec '%s': corrupted symbol #%zu pointing to invalid section #%zu for relo #%d\n",
+				relo_sec_name, sym_idx, (size_t)sym->st_shndx, i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) {
+			pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n",
+				relo_sec_name, (size_t)rel->r_offset, i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		insn_idx = rel->r_offset / BPF_INSN_SZ;
+		/* relocations against static functions are recorded as
+		 * relocations against the section that contains a function;
+		 * in such case, symbol will be STT_SECTION and sym.st_name
+		 * will point to empty string (0), so fetch section name
+		 * instead
+		 */
+		if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION && sym->st_name == 0)
+			sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym->st_shndx));
+		else
+			sym_name = elf_sym_str(obj, sym->st_name);
+		sym_name = sym_name ?: "<?";
+
+		pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n",
+			 relo_sec_name, i, insn_idx, sym_name);
+
+		prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
+		if (!prog) {
+			pr_debug("sec '%s': relo #%d: couldn't find program in section '%s' for insn #%u, probably overridden weak function, skipping...\n",
+				relo_sec_name, i, sec_name, insn_idx);
+			continue;
+		}
+
+		relos = libbpf_reallocarray(prog->reloc_desc,
+					    prog->nr_reloc + 1, sizeof(*relos));
+		if (!relos)
+			return -ENOMEM;
+		prog->reloc_desc = relos;
+
+		/* adjust insn_idx to local BPF program frame of reference */
+		insn_idx -= prog->sec_insn_off;
+		err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc],
+						insn_idx, sym_name, sym, rel);
+		if (err)
+			return err;
+
+		prog->nr_reloc++;
+	}
+	return 0;
+}
+
+static int map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map)
+{
+	int id;
+
+	if (!obj->btf)
+		return -ENOENT;
+
+	/* if it's BTF-defined map, we don't need to search for type IDs.
+	 * For struct_ops map, it does not need btf_key_type_id and
+	 * btf_value_type_id.
+	 */
+	if (map->sec_idx == obj->efile.btf_maps_shndx || bpf_map__is_struct_ops(map))
+		return 0;
+
+	/*
+	 * LLVM annotates global data differently in BTF, that is,
+	 * only as '.data', '.bss', '.percpu' or '.rodata'.
+	 */
+	if (!bpf_map__is_internal(map))
+		return -ENOENT;
+
+	id = btf__find_by_name(obj->btf, map->real_name);
+	if (id < 0)
+		return id;
+
+	map->btf_key_type_id = 0;
+	map->btf_value_type_id = id;
+	return 0;
+}
+
+static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info)
+{
+	char file[PATH_MAX], buff[4096];
+	FILE *fp;
+	__u32 val;
+	int err;
+
+	snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
+	memset(info, 0, sizeof(*info));
+
+	fp = fopen(file, "re");
+	if (!fp) {
+		err = -errno;
+		pr_warn("failed to open %s: %s. No procfs support?\n", file,
+			errstr(err));
+		return err;
+	}
+
+	while (fgets(buff, sizeof(buff), fp)) {
+		if (sscanf(buff, "map_type:\t%u", &val) == 1)
+			info->type = val;
+		else if (sscanf(buff, "key_size:\t%u", &val) == 1)
+			info->key_size = val;
+		else if (sscanf(buff, "value_size:\t%u", &val) == 1)
+			info->value_size = val;
+		else if (sscanf(buff, "max_entries:\t%u", &val) == 1)
+			info->max_entries = val;
+		else if (sscanf(buff, "map_flags:\t%x", &val) == 1)
+			info->map_flags = val;
+	}
+
+	fclose(fp);
+
+	return 0;
+}
+
+static bool map_is_created(const struct bpf_map *map)
+{
+	return map->obj->state >= OBJ_PREPARED || map->reused;
+}
+
+bool bpf_map__autocreate(const struct bpf_map *map)
+{
+	return map->autocreate;
+}
+
+int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+
+	map->autocreate = autocreate;
+	return 0;
+}
+
+int bpf_map__set_autoattach(struct bpf_map *map, bool autoattach)
+{
+	if (!bpf_map__is_struct_ops(map))
+		return libbpf_err(-EINVAL);
+
+	map->autoattach = autoattach;
+	return 0;
+}
+
+bool bpf_map__autoattach(const struct bpf_map *map)
+{
+	return map->autoattach;
+}
+
+int bpf_map__reuse_fd(struct bpf_map *map, int fd)
+{
+	struct bpf_map_info info;
+	__u32 len = sizeof(info), name_len;
+	int new_fd, err;
+	char *new_name;
+
+	memset(&info, 0, len);
+	err = bpf_map_get_info_by_fd(fd, &info, &len);
+	if (err && errno == EINVAL)
+		err = bpf_get_map_info_from_fdinfo(fd, &info);
+	if (err)
+		return libbpf_err(err);
+
+	name_len = strlen(info.name);
+	if (name_len == BPF_OBJ_NAME_LEN - 1 && strncmp(map->name, info.name, name_len) == 0)
+		new_name = strdup(map->name);
+	else
+		new_name = strdup(info.name);
+
+	if (!new_name)
+		return libbpf_err(-errno);
+
+	/*
+	 * Like dup(), but make sure new FD is >= 3 and has O_CLOEXEC set.
+	 * This is similar to what we do in ensure_good_fd(), but without
+	 * closing original FD.
+	 */
+	new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+	if (new_fd < 0) {
+		err = -errno;
+		goto err_free_new_name;
+	}
+
+	err = reuse_fd(map->fd, new_fd);
+	if (err)
+		goto err_free_new_name;
+
+	free(map->name);
+
+	map->name = new_name;
+	map->def.type = info.type;
+	map->def.key_size = info.key_size;
+	map->def.value_size = info.value_size;
+	map->def.max_entries = info.max_entries;
+	map->def.map_flags = info.map_flags;
+	map->btf_key_type_id = info.btf_key_type_id;
+	map->btf_value_type_id = info.btf_value_type_id;
+	map->reused = true;
+	map->map_extra = info.map_extra;
+
+	return 0;
+
+err_free_new_name:
+	free(new_name);
+	return libbpf_err(err);
+}
+
+__u32 bpf_map__max_entries(const struct bpf_map *map)
+{
+	return map->def.max_entries;
+}
+
+struct bpf_map *bpf_map__inner_map(struct bpf_map *map)
+{
+	if (!bpf_map_type__is_map_in_map(map->def.type))
+		return errno = EINVAL, NULL;
+
+	return map->inner_map;
+}
+
+int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+
+	map->def.max_entries = max_entries;
+
+	/* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */
+	if (map_is_ringbuf(map))
+		map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries);
+
+	return 0;
+}
+
+static int bpf_object_prepare_token(struct bpf_object *obj)
+{
+	const char *bpffs_path;
+	int bpffs_fd = -1, token_fd, err;
+	bool mandatory;
+	enum libbpf_print_level level;
+
+	/* token is explicitly prevented */
+	if (obj->token_path && obj->token_path[0] == '\0') {
+		pr_debug("object '%s': token is prevented, skipping...\n", obj->name);
+		return 0;
+	}
+
+	mandatory = obj->token_path != NULL;
+	level = mandatory ? LIBBPF_WARN : LIBBPF_DEBUG;
+
+	bpffs_path = obj->token_path ?: BPF_FS_DEFAULT_PATH;
+	bpffs_fd = open(bpffs_path, O_DIRECTORY, O_RDWR);
+	if (bpffs_fd < 0) {
+		err = -errno;
+		__pr(level, "object '%s': failed (%s) to open BPF FS mount at '%s'%s\n",
+		     obj->name, errstr(err), bpffs_path,
+		     mandatory ? "" : ", skipping optional step...");
+		return mandatory ? err : 0;
+	}
+
+	token_fd = bpf_token_create(bpffs_fd, 0);
+	close(bpffs_fd);
+	if (token_fd < 0) {
+		if (!mandatory && token_fd == -ENOENT) {
+			pr_debug("object '%s': BPF FS at '%s' doesn't have BPF token delegation set up, skipping...\n",
+				 obj->name, bpffs_path);
+			return 0;
+		}
+		__pr(level, "object '%s': failed (%d) to create BPF token from '%s'%s\n",
+		     obj->name, token_fd, bpffs_path,
+		     mandatory ? "" : ", skipping optional step...");
+		return mandatory ? token_fd : 0;
+	}
+
+	obj->feat_cache = calloc(1, sizeof(*obj->feat_cache));
+	if (!obj->feat_cache) {
+		close(token_fd);
+		return -ENOMEM;
+	}
+
+	obj->token_fd = token_fd;
+	obj->feat_cache->token_fd = token_fd;
+
+	return 0;
+}
+
+static int
+bpf_object__probe_loading(struct bpf_object *obj)
+{
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	int ret, insn_cnt = ARRAY_SIZE(insns);
+
+	if (obj->gen_loader || obj->token_fd)
+		return 0;
+
+	ret = bump_rlimit_memlock();
+	if (ret)
+		pr_warn("Failed to bump RLIMIT_MEMLOCK (err = %s), you might need to do it explicitly!\n",
+			errstr(ret));
+
+	/* make sure basic loading works */
+	ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL);
+	if (ret < 0)
+		ret = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL);
+	if (ret < 0) {
+		ret = errno;
+		pr_warn("Error in %s(): %s. Couldn't load trivial BPF program. Make sure your kernel supports BPF (CONFIG_BPF_SYSCALL=y) and/or that RLIMIT_MEMLOCK is set to big enough value.\n",
+			__func__, errstr(ret));
+		return -ret;
+	}
+	close(ret);
+
+	return 0;
+}
+
+bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
+{
+	if (obj->gen_loader)
+		/* To generate loader program assume the latest kernel
+		 * to avoid doing extra prog_load, map_create syscalls.
+		 */
+		return true;
+
+	if (obj->feat_cache)
+		return feat_supported(obj->feat_cache, feat_id);
+
+	return feat_supported(NULL, feat_id);
+}
+
+/* Used in testing to simulate missing features. */
+void bpf_object_set_feat_cache(struct bpf_object *obj, struct kern_feature_cache *cache)
+{
+	if (obj->feat_cache)
+		free(obj->feat_cache);
+	obj->feat_cache = cache;
+}
+
+static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
+{
+	struct bpf_map_info map_info;
+	__u32 map_info_len = sizeof(map_info);
+	int err;
+
+	memset(&map_info, 0, map_info_len);
+	err = bpf_map_get_info_by_fd(map_fd, &map_info, &map_info_len);
+	if (err && errno == EINVAL)
+		err = bpf_get_map_info_from_fdinfo(map_fd, &map_info);
+	if (err) {
+		pr_warn("failed to get map info for map FD %d: %s\n", map_fd,
+			errstr(err));
+		return false;
+	}
+
+	/*
+	 * bpf_get_map_info_by_fd() for DEVMAP will always return flags with
+	 * BPF_F_RDONLY_PROG set, but it generally is not set at map creation time.
+	 * Thus, ignore the BPF_F_RDONLY_PROG flag in the flags returned from
+	 * bpf_get_map_info_by_fd() when checking for compatibility with an
+	 * existing DEVMAP.
+	 */
+	if (map->def.type == BPF_MAP_TYPE_DEVMAP || map->def.type == BPF_MAP_TYPE_DEVMAP_HASH)
+		map_info.map_flags &= ~BPF_F_RDONLY_PROG;
+
+	return (map_info.type == map->def.type &&
+		map_info.key_size == map->def.key_size &&
+		map_info.value_size == map->def.value_size &&
+		map_info.max_entries == map->def.max_entries &&
+		map_info.map_flags == map->def.map_flags &&
+		map_info.map_extra == map->map_extra);
+}
+
+static int
+bpf_object__reuse_map(struct bpf_map *map)
+{
+	int err, pin_fd;
+
+	pin_fd = bpf_obj_get(map->pin_path);
+	if (pin_fd < 0) {
+		err = -errno;
+		if (err == -ENOENT) {
+			pr_debug("found no pinned map to reuse at '%s'\n",
+				 map->pin_path);
+			return 0;
+		}
+
+		pr_warn("couldn't retrieve pinned map '%s': %s\n",
+			map->pin_path, errstr(err));
+		return err;
+	}
+
+	if (!map_is_reuse_compat(map, pin_fd)) {
+		pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
+			map->pin_path);
+		close(pin_fd);
+		return -EINVAL;
+	}
+
+	err = bpf_map__reuse_fd(map, pin_fd);
+	close(pin_fd);
+	if (err)
+		return err;
+
+	map->pinned = true;
+	pr_debug("reused pinned map at '%s'\n", map->pin_path);
+
+	return 0;
+}
+
+static int
+bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
+{
+	enum libbpf_map_type map_type = map->libbpf_type;
+	bool is_percpu = map_type == LIBBPF_MAP_PERCPU;
+	const __u64 update_flags = is_percpu ? BPF_F_ALL_CPUS : 0;
+	int err, zero = 0;
+	size_t mmap_sz;
+
+	if (obj->gen_loader) {
+		bpf_gen__map_update_elem(obj->gen_loader, map - obj->maps,
+					 map->mmaped, map->def.value_size, update_flags);
+		if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG)
+			bpf_gen__map_freeze(obj->gen_loader, map - obj->maps);
+		return 0;
+	}
+
+	err = bpf_map_update_elem(map->fd, &zero, map->mmaped, update_flags);
+	if (err) {
+		err = -errno;
+		pr_warn("map '%s': failed to set initial contents: %s\n",
+			bpf_map__name(map), errstr(err));
+		return err;
+	}
+
+	/* Freeze .rodata and .kconfig map as read-only from syscall side. */
+	if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) {
+		err = bpf_map_freeze(map->fd);
+		if (err) {
+			err = -errno;
+			pr_warn("map '%s': failed to freeze as read-only: %s\n",
+				bpf_map__name(map), errstr(err));
+			return err;
+		}
+	}
+
+	/* Remap anonymous mmap()-ed "map initialization image" as
+	 * a BPF map-backed mmap()-ed memory, but preserving the same
+	 * memory address. This will cause kernel to change process'
+	 * page table to point to a different piece of kernel memory,
+	 * but from userspace point of view memory address (and its
+	 * contents, being identical at this point) will stay the
+	 * same. This mapping will be released by bpf_object__close()
+	 * as per normal clean up procedure.
+	 */
+	mmap_sz = bpf_map_mmap_sz(map);
+	if (map->def.map_flags & BPF_F_MMAPABLE) {
+		void *mmaped;
+		int prot;
+
+		if (map->def.map_flags & BPF_F_RDONLY_PROG)
+			prot = PROT_READ;
+		else
+			prot = PROT_READ | PROT_WRITE;
+		mmaped = mmap(map->mmaped, mmap_sz, prot, MAP_SHARED | MAP_FIXED, map->fd, 0);
+		if (mmaped == MAP_FAILED) {
+			err = -errno;
+			pr_warn("map '%s': failed to re-mmap() contents: %s\n",
+				bpf_map__name(map), errstr(err));
+			return err;
+		}
+		map->mmaped = mmaped;
+	} else if (is_percpu) {
+		if (mprotect(map->mmaped, mmap_sz, PROT_READ)) {
+			err = -errno;
+			pr_warn("map '%s': failed to mprotect() contents: %s\n",
+				bpf_map__name(map), errstr(err));
+			return err;
+		}
+	} else if (map->mmaped) {
+		munmap(map->mmaped, mmap_sz);
+		map->mmaped = NULL;
+	}
+
+	return 0;
+}
+
+static void bpf_map__destroy(struct bpf_map *map);
+
+static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner)
+{
+	LIBBPF_OPTS(bpf_map_create_opts, create_attr);
+	struct bpf_map_def *def = &map->def;
+	const char *map_name = NULL;
+	int err = 0, map_fd;
+
+	if (kernel_supports(obj, FEAT_PROG_NAME))
+		map_name = map->name;
+	create_attr.map_ifindex = map->map_ifindex;
+	create_attr.map_flags = def->map_flags;
+	create_attr.numa_node = map->numa_node;
+	create_attr.map_extra = map->map_extra;
+	create_attr.token_fd = obj->token_fd;
+	if (obj->token_fd)
+		create_attr.map_flags |= BPF_F_TOKEN_FD;
+	if (map->excl_prog) {
+		err = bpf_prog_compute_hash(map->excl_prog);
+		if (err)
+			return err;
+
+		create_attr.excl_prog_hash = map->excl_prog->hash;
+		create_attr.excl_prog_hash_size = SHA256_DIGEST_LENGTH;
+	}
+
+	if (bpf_map__is_struct_ops(map)) {
+		create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id;
+		if (map->mod_btf_fd >= 0) {
+			create_attr.value_type_btf_obj_fd = map->mod_btf_fd;
+			create_attr.map_flags |= BPF_F_VTYPE_BTF_OBJ_FD;
+		}
+	}
+
+	if (obj->btf && btf__fd(obj->btf) >= 0) {
+		create_attr.btf_fd = btf__fd(obj->btf);
+		create_attr.btf_key_type_id = map->btf_key_type_id;
+		create_attr.btf_value_type_id = map->btf_value_type_id;
+	}
+
+	if (bpf_map_type__is_map_in_map(def->type)) {
+		if (map->inner_map) {
+			err = map_set_def_max_entries(map->inner_map);
+			if (err)
+				return err;
+			err = bpf_object__create_map(obj, map->inner_map, true);
+			if (err) {
+				pr_warn("map '%s': failed to create inner map: %s\n",
+					map->name, errstr(err));
+				return err;
+			}
+			map->inner_map_fd = map->inner_map->fd;
+		}
+		if (map->inner_map_fd >= 0)
+			create_attr.inner_map_fd = map->inner_map_fd;
+	}
+
+	switch (def->type) {
+	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
+	case BPF_MAP_TYPE_CGROUP_ARRAY:
+	case BPF_MAP_TYPE_STACK_TRACE:
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+	case BPF_MAP_TYPE_DEVMAP:
+	case BPF_MAP_TYPE_DEVMAP_HASH:
+	case BPF_MAP_TYPE_CPUMAP:
+	case BPF_MAP_TYPE_XSKMAP:
+	case BPF_MAP_TYPE_SOCKMAP:
+	case BPF_MAP_TYPE_SOCKHASH:
+	case BPF_MAP_TYPE_QUEUE:
+	case BPF_MAP_TYPE_STACK:
+	case BPF_MAP_TYPE_ARENA:
+		create_attr.btf_fd = 0;
+		create_attr.btf_key_type_id = 0;
+		create_attr.btf_value_type_id = 0;
+		map->btf_key_type_id = 0;
+		map->btf_value_type_id = 0;
+		break;
+	case BPF_MAP_TYPE_STRUCT_OPS:
+		create_attr.btf_value_type_id = 0;
+		break;
+	default:
+		break;
+	}
+
+	if (obj->gen_loader) {
+		bpf_gen__map_create(obj->gen_loader, def->type, map_name,
+				    def->key_size, def->value_size, def->max_entries,
+				    &create_attr, is_inner ? -1 : map - obj->maps);
+		/* We keep pretenting we have valid FD to pass various fd >= 0
+		 * checks by just keeping original placeholder FDs in place.
+		 * See bpf_object__add_map() comment.
+		 * This placeholder fd will not be used with any syscall and
+		 * will be reset to -1 eventually.
+		 */
+		map_fd = map->fd;
+	} else {
+		map_fd = bpf_map_create(def->type, map_name,
+					def->key_size, def->value_size,
+					def->max_entries, &create_attr);
+	}
+	if (map_fd < 0 && (create_attr.btf_key_type_id || create_attr.btf_value_type_id)) {
+		err = -errno;
+		pr_warn("Error in bpf_create_map_xattr(%s): %s. Retrying without BTF.\n",
+			map->name, errstr(err));
+		create_attr.btf_fd = 0;
+		create_attr.btf_key_type_id = 0;
+		create_attr.btf_value_type_id = 0;
+		map->btf_key_type_id = 0;
+		map->btf_value_type_id = 0;
+		map_fd = bpf_map_create(def->type, map_name,
+					def->key_size, def->value_size,
+					def->max_entries, &create_attr);
+	}
+
+	if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) {
+		if (obj->gen_loader)
+			map->inner_map->fd = -1;
+		bpf_map__destroy(map->inner_map);
+		zfree(&map->inner_map);
+	}
+
+	if (map_fd < 0)
+		return map_fd;
+
+	/* obj->gen_loader case, prevent reuse_fd() from closing map_fd */
+	if (map->fd == map_fd)
+		return 0;
+
+	/* Keep placeholder FD value but now point it to the BPF map object.
+	 * This way everything that relied on this map's FD (e.g., relocated
+	 * ldimm64 instructions) will stay valid and won't need adjustments.
+	 * map->fd stays valid but now point to what map_fd points to.
+	 */
+	return reuse_fd(map->fd, map_fd);
+}
+
+static int init_map_in_map_slots(struct bpf_object *obj, struct bpf_map *map)
+{
+	const struct bpf_map *targ_map;
+	unsigned int i;
+	int fd, err = 0;
+
+	for (i = 0; i < map->init_slots_sz; i++) {
+		if (!map->init_slots[i])
+			continue;
+
+		targ_map = map->init_slots[i];
+		fd = targ_map->fd;
+
+		if (obj->gen_loader) {
+			bpf_gen__populate_outer_map(obj->gen_loader,
+						    map - obj->maps, i,
+						    targ_map - obj->maps);
+		} else {
+			err = bpf_map_update_elem(map->fd, &i, &fd, 0);
+		}
+		if (err) {
+			err = -errno;
+			pr_warn("map '%s': failed to initialize slot [%u] to map '%s' fd=%d: %s\n",
+				map->name, i, targ_map->name, fd, errstr(err));
+			return err;
+		}
+		pr_debug("map '%s': slot [%u] set to map '%s' fd=%d\n",
+			 map->name, i, targ_map->name, fd);
+	}
+
+	zfree(&map->init_slots);
+	map->init_slots_sz = 0;
+
+	return 0;
+}
+
+static int init_prog_array_slots(struct bpf_object *obj, struct bpf_map *map)
+{
+	const struct bpf_program *targ_prog;
+	unsigned int i;
+	int fd, err;
+
+	if (obj->gen_loader)
+		return -ENOTSUP;
+
+	for (i = 0; i < map->init_slots_sz; i++) {
+		if (!map->init_slots[i])
+			continue;
+
+		targ_prog = map->init_slots[i];
+		fd = bpf_program__fd(targ_prog);
+
+		err = bpf_map_update_elem(map->fd, &i, &fd, 0);
+		if (err) {
+			err = -errno;
+			pr_warn("map '%s': failed to initialize slot [%u] to prog '%s' fd=%d: %s\n",
+				map->name, i, targ_prog->name, fd, errstr(err));
+			return err;
+		}
+		pr_debug("map '%s': slot [%u] set to prog '%s' fd=%d\n",
+			 map->name, i, targ_prog->name, fd);
+	}
+
+	zfree(&map->init_slots);
+	map->init_slots_sz = 0;
+
+	return 0;
+}
+
+static int bpf_object_init_prog_arrays(struct bpf_object *obj)
+{
+	struct bpf_map *map;
+	int i, err;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		map = &obj->maps[i];
+
+		if (!map->init_slots_sz || map->def.type != BPF_MAP_TYPE_PROG_ARRAY)
+			continue;
+
+		err = init_prog_array_slots(obj, map);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static int map_set_def_max_entries(struct bpf_map *map)
+{
+	if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->def.max_entries) {
+		int nr_cpus;
+
+		nr_cpus = libbpf_num_possible_cpus();
+		if (nr_cpus < 0) {
+			pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
+				map->name, nr_cpus);
+			return nr_cpus;
+		}
+		pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
+		map->def.max_entries = nr_cpus;
+	}
+
+	return 0;
+}
+
+static int
+bpf_object__create_maps(struct bpf_object *obj)
+{
+	struct bpf_map *map;
+	unsigned int i, j;
+	int err;
+	bool retried;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		map = &obj->maps[i];
+
+		/* To support old kernels, we skip creating global data maps
+		 * (.rodata, .data, .kconfig, etc); later on, during program
+		 * loading, if we detect that at least one of the to-be-loaded
+		 * programs is referencing any global data map, we'll error
+		 * out with program name and relocation index logged.
+		 * This approach allows to accommodate Clang emitting
+		 * unnecessary .rodata.str1.1 sections for string literals,
+		 * but also it allows to have CO-RE applications that use
+		 * global variables in some of BPF programs, but not others.
+		 * If those global variable-using programs are not loaded at
+		 * runtime due to bpf_program__set_autoload(prog, false),
+		 * bpf_object loading will succeed just fine even on old
+		 * kernels.
+		 * Same skipping applies to percpu data.
+		 */
+		if (bpf_map__is_internal(map)) {
+			bool is_percpu = map->libbpf_type == LIBBPF_MAP_PERCPU;
+			enum kern_feature_id feat_id;
+
+			feat_id = is_percpu ? FEAT_PERCPU_DATA : FEAT_GLOBAL_DATA;
+			if (!kernel_supports(obj, feat_id))
+				map->autocreate = false;
+		}
+
+		if (!map->autocreate) {
+			pr_debug("map '%s': skipped auto-creating...\n", map->name);
+			continue;
+		}
+
+		err = map_set_def_max_entries(map);
+		if (err)
+			goto err_out;
+
+		retried = false;
+retry:
+		if (map->pin_path) {
+			err = bpf_object__reuse_map(map);
+			if (err) {
+				pr_warn("map '%s': error reusing pinned map\n",
+					map->name);
+				goto err_out;
+			}
+			if (retried && map->fd < 0) {
+				pr_warn("map '%s': cannot find pinned map\n",
+					map->name);
+				err = -ENOENT;
+				goto err_out;
+			}
+		}
+
+		if (map->reused) {
+			pr_debug("map '%s': skipping creation (preset fd=%d)\n",
+				 map->name, map->fd);
+		} else {
+			err = bpf_object__create_map(obj, map, false);
+			if (err)
+				goto err_out;
+
+			pr_debug("map '%s': created successfully, fd=%d\n",
+				 map->name, map->fd);
+
+			if (bpf_map__is_internal(map)) {
+				err = bpf_object__populate_internal_map(obj, map);
+				if (err < 0)
+					goto err_out;
+			} else if (map->def.type == BPF_MAP_TYPE_ARENA) {
+				map->mmaped = mmap((void *)(long)map->map_extra,
+						   bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
+						   map->map_extra ? MAP_SHARED | MAP_FIXED : MAP_SHARED,
+						   map->fd, 0);
+				if (map->mmaped == MAP_FAILED) {
+					err = -errno;
+					map->mmaped = NULL;
+					pr_warn("map '%s': failed to mmap arena: %s\n",
+						map->name, errstr(err));
+					return err;
+				}
+				if (obj->arena_data) {
+					memcpy(map->mmaped + obj->arena_data_off, obj->arena_data,
+						obj->arena_data_sz);
+					zfree(&obj->arena_data);
+				}
+			}
+			if (map->init_slots_sz && map->def.type != BPF_MAP_TYPE_PROG_ARRAY) {
+				err = init_map_in_map_slots(obj, map);
+				if (err < 0)
+					goto err_out;
+			}
+		}
+
+		if (map->pin_path && !map->pinned) {
+			err = bpf_map__pin(map, NULL);
+			if (err) {
+				if (!retried && err == -EEXIST) {
+					retried = true;
+					goto retry;
+				}
+				pr_warn("map '%s': failed to auto-pin at '%s': %s\n",
+					map->name, map->pin_path, errstr(err));
+				goto err_out;
+			}
+		}
+	}
+
+	return 0;
+
+err_out:
+	pr_warn("map '%s': failed to create: %s\n", map->name, errstr(err));
+	pr_perm_msg(err);
+	for (j = 0; j < i; j++)
+		zclose(obj->maps[j].fd);
+	return err;
+}
+
+static bool bpf_core_is_flavor_sep(const char *s)
+{
+	/* check X___Y name pattern, where X and Y are not underscores */
+	return s[0] != '_' &&				      /* X */
+	       s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
+	       s[4] != '_';				      /* Y */
+}
+
+/* Given 'some_struct_name___with_flavor' return the length of a name prefix
+ * before last triple underscore. Struct name part after last triple
+ * underscore is ignored by BPF CO-RE relocation during relocation matching.
+ */
+size_t bpf_core_essential_name_len(const char *name)
+{
+	size_t n = strlen(name);
+	int i;
+
+	for (i = n - 5; i >= 0; i--) {
+		if (bpf_core_is_flavor_sep(name + i))
+			return i + 1;
+	}
+	return n;
+}
+
+void bpf_core_free_cands(struct bpf_core_cand_list *cands)
+{
+	if (!cands)
+		return;
+
+	free(cands->cands);
+	free(cands);
+}
+
+int bpf_core_add_cands(struct bpf_core_cand *local_cand,
+		       size_t local_essent_len,
+		       const struct btf *targ_btf,
+		       const char *targ_btf_name,
+		       int targ_start_id,
+		       struct bpf_core_cand_list *cands)
+{
+	struct bpf_core_cand *new_cands, *cand;
+	const struct btf_type *t, *local_t;
+	const char *targ_name, *local_name;
+	size_t targ_essent_len;
+	int n, i;
+
+	local_t = btf__type_by_id(local_cand->btf, local_cand->id);
+	local_name = btf__str_by_offset(local_cand->btf, local_t->name_off);
+
+	n = btf__type_cnt(targ_btf);
+	for (i = targ_start_id; i < n; i++) {
+		t = btf__type_by_id(targ_btf, i);
+		if (!btf_kind_core_compat(t, local_t))
+			continue;
+
+		targ_name = btf__name_by_offset(targ_btf, t->name_off);
+		if (str_is_empty(targ_name))
+			continue;
+
+		targ_essent_len = bpf_core_essential_name_len(targ_name);
+		if (targ_essent_len != local_essent_len)
+			continue;
+
+		if (strncmp(local_name, targ_name, local_essent_len) != 0)
+			continue;
+
+		pr_debug("CO-RE relocating [%u] %s %s: found target candidate [%d] %s %s in [%s]\n",
+			 local_cand->id, btf_kind_str(local_t),
+			 local_name, i, btf_kind_str(t), targ_name,
+			 targ_btf_name);
+		new_cands = libbpf_reallocarray(cands->cands, cands->len + 1,
+					      sizeof(*cands->cands));
+		if (!new_cands)
+			return -ENOMEM;
+
+		cand = &new_cands[cands->len];
+		cand->btf = targ_btf;
+		cand->id = i;
+
+		cands->cands = new_cands;
+		cands->len++;
+	}
+	return 0;
+}
+
+static int load_module_btfs(struct bpf_object *obj)
+{
+	struct bpf_btf_info info;
+	struct module_btf *mod_btf;
+	struct btf *btf;
+	char name[64];
+	__u32 id = 0, len;
+	int err, fd;
+
+	if (obj->btf_modules_loaded)
+		return 0;
+
+	if (obj->gen_loader)
+		return 0;
+
+	/* don't do this again, even if we find no module BTFs */
+	obj->btf_modules_loaded = true;
+
+	/* kernel too old to support module BTFs */
+	if (!kernel_supports(obj, FEAT_MODULE_BTF))
+		return 0;
+
+	while (true) {
+		err = bpf_btf_get_next_id(id, &id);
+		if (err && errno == ENOENT)
+			return 0;
+		if (err && errno == EPERM) {
+			pr_debug("skipping module BTFs loading, missing privileges\n");
+			return 0;
+		}
+		if (err) {
+			err = -errno;
+			pr_warn("failed to iterate BTF objects: %s\n", errstr(err));
+			return err;
+		}
+
+		fd = bpf_btf_get_fd_by_id(id);
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue; /* expected race: BTF was unloaded */
+			err = -errno;
+			pr_warn("failed to get BTF object #%u FD: %s\n", id, errstr(err));
+			return err;
+		}
+
+		len = sizeof(info);
+		memset(&info, 0, sizeof(info));
+		info.name = ptr_to_u64(name);
+		info.name_len = sizeof(name);
+
+		btf = NULL;
+		err = bpf_btf_get_info_by_fd(fd, &info, &len);
+		if (err) {
+			err = -errno;
+			pr_warn("failed to get BTF object #%u info: %s\n", id, errstr(err));
+			break;
+		}
+
+		/* ignore non-module BTFs */
+		if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) {
+			close(fd);
+			continue;
+		}
+
+		btf = btf_get_from_fd(fd, obj->btf_vmlinux);
+		err = libbpf_get_error(btf);
+		if (err) {
+			pr_warn("failed to load module [%s]'s BTF object #%u: %s\n",
+				name, id, errstr(err));
+			break;
+		}
+
+		err = libbpf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap,
+					sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);
+		if (err)
+			break;
+
+		mod_btf = &obj->btf_modules[obj->btf_module_cnt];
+
+		mod_btf->btf = btf;
+		mod_btf->id = id;
+		mod_btf->fd = fd;
+		mod_btf->name = strdup(name);
+		if (!mod_btf->name) {
+			err = -ENOMEM;
+			break;
+		}
+		obj->btf_module_cnt++;
+	}
+
+	if (err) {
+		btf__free(btf);
+		close(fd);
+	}
+	return err;
+}
+
+static struct bpf_core_cand_list *
+bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
+{
+	struct bpf_core_cand local_cand = {};
+	struct bpf_core_cand_list *cands;
+	const struct btf *main_btf;
+	const struct btf_type *local_t;
+	const char *local_name;
+	size_t local_essent_len;
+	int err, i;
+
+	local_cand.btf = local_btf;
+	local_cand.id = local_type_id;
+	local_t = btf__type_by_id(local_btf, local_type_id);
+	if (!local_t)
+		return ERR_PTR(-EINVAL);
+
+	local_name = btf__name_by_offset(local_btf, local_t->name_off);
+	if (str_is_empty(local_name))
+		return ERR_PTR(-EINVAL);
+	local_essent_len = bpf_core_essential_name_len(local_name);
+
+	cands = calloc(1, sizeof(*cands));
+	if (!cands)
+		return ERR_PTR(-ENOMEM);
+
+	/* Attempt to find target candidates in vmlinux BTF first */
+	main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
+	err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
+	if (err)
+		goto err_out;
+
+	/* if vmlinux BTF has any candidate, don't got for module BTFs */
+	if (cands->len)
+		return cands;
+
+	/* if vmlinux BTF was overridden, don't attempt to load module BTFs */
+	if (obj->btf_vmlinux_override)
+		return cands;
+
+	/* now look through module BTFs, trying to still find candidates */
+	err = load_module_btfs(obj);
+	if (err)
+		goto err_out;
+
+	for (i = 0; i < obj->btf_module_cnt; i++) {
+		err = bpf_core_add_cands(&local_cand, local_essent_len,
+					 obj->btf_modules[i].btf,
+					 obj->btf_modules[i].name,
+					 btf__type_cnt(obj->btf_vmlinux),
+					 cands);
+		if (err)
+			goto err_out;
+	}
+
+	return cands;
+err_out:
+	bpf_core_free_cands(cands);
+	return ERR_PTR(err);
+}
+
+/* Check local and target types for compatibility. This check is used for
+ * type-based CO-RE relocations and follow slightly different rules than
+ * field-based relocations. This function assumes that root types were already
+ * checked for name match. Beyond that initial root-level name check, names
+ * are completely ignored. Compatibility rules are as follows:
+ *   - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but
+ *     kind should match for local and target types (i.e., STRUCT is not
+ *     compatible with UNION);
+ *   - for ENUMs, the size is ignored;
+ *   - for INT, size and signedness are ignored;
+ *   - for ARRAY, dimensionality is ignored, element types are checked for
+ *     compatibility recursively;
+ *   - CONST/VOLATILE/RESTRICT modifiers are ignored;
+ *   - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
+ *   - FUNC_PROTOs are compatible if they have compatible signature: same
+ *     number of input args and compatible return and argument types.
+ * These rules are not set in stone and probably will be adjusted as we get
+ * more experience with using BPF CO-RE relocations.
+ */
+int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
+			      const struct btf *targ_btf, __u32 targ_id)
+{
+	return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id, 32);
+}
+
+int bpf_core_types_match(const struct btf *local_btf, __u32 local_id,
+			 const struct btf *targ_btf, __u32 targ_id)
+{
+	return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32);
+}
+
+static size_t bpf_core_hash_fn(const long key, void *ctx)
+{
+	return key;
+}
+
+static bool bpf_core_equal_fn(const long k1, const long k2, void *ctx)
+{
+	return k1 == k2;
+}
+
+static int record_relo_core(struct bpf_program *prog,
+			    const struct bpf_core_relo *core_relo, int insn_idx)
+{
+	struct reloc_desc *relos, *relo;
+
+	relos = libbpf_reallocarray(prog->reloc_desc,
+				    prog->nr_reloc + 1, sizeof(*relos));
+	if (!relos)
+		return -ENOMEM;
+	relo = &relos[prog->nr_reloc];
+	relo->type = RELO_CORE;
+	relo->insn_idx = insn_idx;
+	relo->core_relo = core_relo;
+	prog->reloc_desc = relos;
+	prog->nr_reloc++;
+	return 0;
+}
+
+static const struct bpf_core_relo *find_relo_core(struct bpf_program *prog, int insn_idx)
+{
+	struct reloc_desc *relo;
+	int i;
+
+	for (i = 0; i < prog->nr_reloc; i++) {
+		relo = &prog->reloc_desc[i];
+		if (relo->type != RELO_CORE || relo->insn_idx != insn_idx)
+			continue;
+
+		return relo->core_relo;
+	}
+
+	return NULL;
+}
+
+static int bpf_core_resolve_relo(struct bpf_program *prog,
+				 const struct bpf_core_relo *relo,
+				 int relo_idx,
+				 const struct btf *local_btf,
+				 struct hashmap *cand_cache,
+				 struct bpf_core_relo_res *targ_res)
+{
+	struct bpf_core_spec specs_scratch[3] = {};
+	struct bpf_core_cand_list *cands = NULL;
+	const char *prog_name = prog->name;
+	const struct btf_type *local_type;
+	const char *local_name;
+	__u32 local_id = relo->type_id;
+	int err;
+
+	local_type = btf__type_by_id(local_btf, local_id);
+	if (!local_type)
+		return -EINVAL;
+
+	local_name = btf__name_by_offset(local_btf, local_type->name_off);
+	if (!local_name)
+		return -EINVAL;
+
+	if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
+	    !hashmap__find(cand_cache, local_id, &cands)) {
+		cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
+		if (IS_ERR(cands)) {
+			pr_warn("prog '%s': relo #%d: target candidate search failed for [%u] %s %s: %ld\n",
+				prog_name, relo_idx, local_id, btf_kind_str(local_type),
+				local_name, PTR_ERR(cands));
+			return PTR_ERR(cands);
+		}
+		err = hashmap__set(cand_cache, local_id, cands, NULL, NULL);
+		if (err) {
+			bpf_core_free_cands(cands);
+			return err;
+		}
+	}
+
+	return bpf_core_calc_relo_insn(prog_name, relo, relo_idx, local_btf, cands, specs_scratch,
+				       targ_res);
+}
+
+static int
+bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
+{
+	const struct btf_ext_info_sec *sec;
+	struct bpf_core_relo_res targ_res;
+	const struct bpf_core_relo *rec;
+	const struct btf_ext_info *seg;
+	struct hashmap_entry *entry;
+	struct hashmap *cand_cache = NULL;
+	struct bpf_program *prog;
+	struct bpf_insn *insn;
+	const char *sec_name;
+	int i, err = 0, insn_idx, sec_idx, sec_num;
+
+	if (obj->btf_ext->core_relo_info.len == 0)
+		return 0;
+
+	if (targ_btf_path) {
+		obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL);
+		err = libbpf_get_error(obj->btf_vmlinux_override);
+		if (err) {
+			pr_warn("failed to parse target BTF: %s\n", errstr(err));
+			return err;
+		}
+	}
+
+	cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
+	if (IS_ERR(cand_cache)) {
+		err = PTR_ERR(cand_cache);
+		goto out;
+	}
+
+	seg = &obj->btf_ext->core_relo_info;
+	sec_num = 0;
+	for_each_btf_ext_sec(seg, sec) {
+		sec_idx = seg->sec_idxs[sec_num];
+		sec_num++;
+
+		sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
+		if (str_is_empty(sec_name)) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		pr_debug("sec '%s': found %u CO-RE relocations\n", sec_name, sec->num_info);
+
+		for_each_btf_ext_rec(seg, sec, i, rec) {
+			if (rec->insn_off % BPF_INSN_SZ)
+				return -EINVAL;
+			insn_idx = rec->insn_off / BPF_INSN_SZ;
+			prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
+			if (!prog) {
+				/* When __weak subprog is "overridden" by another instance
+				 * of the subprog from a different object file, linker still
+				 * appends all the .BTF.ext info that used to belong to that
+				 * eliminated subprogram.
+				 * This is similar to what x86-64 linker does for relocations.
+				 * So just ignore such relocations just like we ignore
+				 * subprog instructions when discovering subprograms.
+				 */
+				pr_debug("sec '%s': skipping CO-RE relocation #%d for insn #%d belonging to eliminated weak subprogram\n",
+					 sec_name, i, insn_idx);
+				continue;
+			}
+			/* no need to apply CO-RE relocation if the program is
+			 * not going to be loaded
+			 */
+			if (!prog->autoload)
+				continue;
+
+			/* adjust insn_idx from section frame of reference to the local
+			 * program's frame of reference; (sub-)program code is not yet
+			 * relocated, so it's enough to just subtract in-section offset
+			 */
+			insn_idx = insn_idx - prog->sec_insn_off;
+			if (insn_idx >= prog->insns_cnt)
+				return -EINVAL;
+			insn = &prog->insns[insn_idx];
+
+			err = record_relo_core(prog, rec, insn_idx);
+			if (err) {
+				pr_warn("prog '%s': relo #%d: failed to record relocation: %s\n",
+					prog->name, i, errstr(err));
+				goto out;
+			}
+
+			if (prog->obj->gen_loader)
+				continue;
+
+			err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
+			if (err) {
+				pr_warn("prog '%s': relo #%d: failed to relocate: %s\n",
+					prog->name, i, errstr(err));
+				goto out;
+			}
+
+			err = bpf_core_patch_insn(prog->name, insn, insn_idx, rec, i, &targ_res);
+			if (err) {
+				pr_warn("prog '%s': relo #%d: failed to patch insn #%d: %s\n",
+					prog->name, i, insn_idx, errstr(err));
+				goto out;
+			}
+		}
+	}
+
+out:
+	/* obj->btf_vmlinux and module BTFs are freed after object load */
+	btf__free(obj->btf_vmlinux_override);
+	obj->btf_vmlinux_override = NULL;
+
+	if (!IS_ERR_OR_NULL(cand_cache)) {
+		hashmap__for_each_entry(cand_cache, entry, i) {
+			bpf_core_free_cands(entry->pvalue);
+		}
+		hashmap__free(cand_cache);
+	}
+	return err;
+}
+
+/* base map load ldimm64 special constant, used also for log fixup logic */
+#define POISON_LDIMM64_MAP_BASE 2001000000
+#define POISON_LDIMM64_MAP_PFX "200100"
+
+static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx,
+			       int insn_idx, struct bpf_insn *insn,
+			       int map_idx, const struct bpf_map *map)
+{
+	int i;
+
+	pr_debug("prog '%s': relo #%d: poisoning insn #%d that loads map #%d '%s'\n",
+		 prog->name, relo_idx, insn_idx, map_idx, map->name);
+
+	/* we turn single ldimm64 into two identical invalid calls */
+	for (i = 0; i < 2; i++) {
+		insn->code = BPF_JMP | BPF_CALL;
+		insn->dst_reg = 0;
+		insn->src_reg = 0;
+		insn->off = 0;
+		/* if this instruction is reachable (not a dead code),
+		 * verifier will complain with something like:
+		 * invalid func unknown#2001000123
+		 * where lower 123 is map index into obj->maps[] array
+		 */
+		insn->imm = POISON_LDIMM64_MAP_BASE + map_idx;
+
+		insn++;
+	}
+}
+
+/* unresolved kfunc call special constant, used also for log fixup logic */
+#define POISON_CALL_KFUNC_BASE 2002000000
+#define POISON_CALL_KFUNC_PFX "2002"
+
+static void poison_kfunc_call(struct bpf_program *prog, int relo_idx,
+			      int insn_idx, struct bpf_insn *insn,
+			      int ext_idx, const struct extern_desc *ext)
+{
+	pr_debug("prog '%s': relo #%d: poisoning insn #%d that calls kfunc '%s'\n",
+		 prog->name, relo_idx, insn_idx, ext->name);
+
+	/* we turn kfunc call into invalid helper call with identifiable constant */
+	insn->code = BPF_JMP | BPF_CALL;
+	insn->dst_reg = 0;
+	insn->src_reg = 0;
+	insn->off = 0;
+	/* if this instruction is reachable (not a dead code),
+	 * verifier will complain with something like:
+	 * invalid func unknown#2001000123
+	 * where lower 123 is extern index into obj->externs[] array
+	 */
+	insn->imm = POISON_CALL_KFUNC_BASE + ext_idx;
+}
+
+static int find_jt_map(struct bpf_object *obj, struct bpf_program *prog, unsigned int sym_off)
+{
+	size_t i;
+
+	for (i = 0; i < obj->jumptable_map_cnt; i++) {
+		/*
+		 * This might happen that same offset is used for two different
+		 * programs (as jump tables can be the same). However, for
+		 * different programs different maps should be created.
+		 */
+		if (obj->jumptable_maps[i].sym_off == sym_off &&
+		    obj->jumptable_maps[i].prog == prog)
+			return obj->jumptable_maps[i].fd;
+	}
+
+	return -ENOENT;
+}
+
+static int add_jt_map(struct bpf_object *obj, struct bpf_program *prog, unsigned int sym_off, int map_fd)
+{
+	size_t cnt = obj->jumptable_map_cnt;
+	size_t size = sizeof(obj->jumptable_maps[0]);
+	void *tmp;
+
+	tmp = libbpf_reallocarray(obj->jumptable_maps, cnt + 1, size);
+	if (!tmp)
+		return -ENOMEM;
+
+	obj->jumptable_maps = tmp;
+	obj->jumptable_maps[cnt].prog = prog;
+	obj->jumptable_maps[cnt].sym_off = sym_off;
+	obj->jumptable_maps[cnt].fd = map_fd;
+	obj->jumptable_map_cnt++;
+
+	return 0;
+}
+
+static int find_subprog_idx(struct bpf_program *prog, int insn_idx)
+{
+	int i;
+
+	for (i = prog->subprog_cnt - 1; i >= 0; i--) {
+		if (insn_idx >= prog->subprogs[i].sub_insn_off)
+			return i;
+	}
+
+	return -1;
+}
+
+static int create_jt_map(struct bpf_object *obj, struct bpf_program *prog, struct reloc_desc *relo)
+{
+	const __u32 jt_entry_size = 8;
+	unsigned int sym_off = relo->sym_off;
+	int jt_size = relo->sym_size;
+	__u32 max_entries = jt_size / jt_entry_size;
+	__u32 value_size = sizeof(struct bpf_insn_array_value);
+	struct bpf_insn_array_value val = {};
+	int subprog_idx;
+	int map_fd, err;
+	__u64 insn_off;
+	__u64 *jt;
+	__u32 i;
+
+	map_fd = find_jt_map(obj, prog, sym_off);
+	if (map_fd >= 0)
+		return map_fd;
+
+	if (sym_off % jt_entry_size) {
+		pr_warn("map '.jumptables': jumptable start %u should be multiple of %u\n",
+			sym_off, jt_entry_size);
+		return -EINVAL;
+	}
+
+	if (jt_size % jt_entry_size) {
+		pr_warn("map '.jumptables': jumptable size %d should be multiple of %u\n",
+			jt_size, jt_entry_size);
+		return -EINVAL;
+	}
+
+	map_fd = bpf_map_create(BPF_MAP_TYPE_INSN_ARRAY, ".jumptables",
+				4, value_size, max_entries, NULL);
+	if (map_fd < 0)
+		return map_fd;
+
+	if (!obj->jumptables_data) {
+		pr_warn("map '.jumptables': ELF file is missing jump table data\n");
+		err = -EINVAL;
+		goto err_close;
+	}
+	if (sym_off + jt_size > obj->jumptables_data_sz) {
+		pr_warn("map '.jumptables': jumptables_data size is %zu, trying to access %u\n",
+			obj->jumptables_data_sz, sym_off + jt_size);
+		err = -EINVAL;
+		goto err_close;
+	}
+
+	subprog_idx = -1; /* main program */
+	if (relo->insn_idx < 0 || relo->insn_idx >= prog->insns_cnt) {
+		pr_warn("map '.jumptables': invalid instruction index %d\n", relo->insn_idx);
+		err = -EINVAL;
+		goto err_close;
+	}
+	if (prog->subprogs)
+		subprog_idx = find_subprog_idx(prog, relo->insn_idx);
+
+	jt = (__u64 *)(obj->jumptables_data + sym_off);
+	for (i = 0; i < max_entries; i++) {
+		/*
+		 * The offset should be made to be relative to the beginning of
+		 * the main function, not the subfunction.
+		 */
+		insn_off = jt[i]/sizeof(struct bpf_insn);
+		if (subprog_idx >= 0) {
+			insn_off -= prog->subprogs[subprog_idx].sec_insn_off;
+			insn_off += prog->subprogs[subprog_idx].sub_insn_off;
+		} else {
+			insn_off -= prog->sec_insn_off;
+		}
+
+		/*
+		 * LLVM-generated jump tables contain u64 records, however
+		 * should contain values that fit in u32.
+		 */
+		if (insn_off > UINT32_MAX) {
+			pr_warn("map '.jumptables': invalid jump table value 0x%llx at offset %u\n",
+				(unsigned long long)jt[i], sym_off + i * jt_entry_size);
+			err = -EINVAL;
+			goto err_close;
+		}
+
+		val.orig_off = insn_off;
+		err = bpf_map_update_elem(map_fd, &i, &val, 0);
+		if (err)
+			goto err_close;
+	}
+
+	err = bpf_map_freeze(map_fd);
+	if (err)
+		goto err_close;
+
+	err = add_jt_map(obj, prog, sym_off, map_fd);
+	if (err)
+		goto err_close;
+
+	return map_fd;
+
+err_close:
+	close(map_fd);
+	return err;
+}
+
+/* Relocate data references within program code:
+ *  - map references;
+ *  - global variable references;
+ *  - extern references.
+ */
+static int
+bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
+{
+	int i;
+
+	for (i = 0; i < prog->nr_reloc; i++) {
+		struct reloc_desc *relo = &prog->reloc_desc[i];
+		struct bpf_insn *insn = &prog->insns[relo->insn_idx];
+		const struct bpf_map *map;
+		struct extern_desc *ext;
+
+		switch (relo->type) {
+		case RELO_LD64:
+			map = &obj->maps[relo->map_idx];
+			if (obj->gen_loader) {
+				insn[0].src_reg = BPF_PSEUDO_MAP_IDX;
+				insn[0].imm = relo->map_idx;
+			} else if (map->autocreate) {
+				insn[0].src_reg = BPF_PSEUDO_MAP_FD;
+				insn[0].imm = map->fd;
+			} else {
+				poison_map_ldimm64(prog, i, relo->insn_idx, insn,
+						   relo->map_idx, map);
+			}
+			break;
+		case RELO_DATA:
+			map = &obj->maps[relo->map_idx];
+			insn[1].imm = insn[0].imm + relo->sym_off;
+
+			if (relo->map_idx == obj->arena_map_idx)
+				insn[1].imm += obj->arena_data_off;
+
+			if (obj->gen_loader) {
+				insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
+				insn[0].imm = relo->map_idx;
+			} else if (map->autocreate) {
+				insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
+				insn[0].imm = map->fd;
+			} else {
+				poison_map_ldimm64(prog, i, relo->insn_idx, insn,
+						   relo->map_idx, map);
+			}
+			break;
+		case RELO_EXTERN_LD64:
+			ext = &obj->externs[relo->ext_idx];
+			if (ext->type == EXT_KCFG) {
+				if (obj->gen_loader) {
+					insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
+					insn[0].imm = obj->kconfig_map_idx;
+				} else {
+					insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
+					insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
+				}
+				insn[1].imm = ext->kcfg.data_off;
+			} else /* EXT_KSYM */ {
+				if (ext->ksym.type_id && ext->is_set) { /* typed ksyms */
+					insn[0].src_reg = BPF_PSEUDO_BTF_ID;
+					insn[0].imm = ext->ksym.kernel_btf_id;
+					insn[1].imm = ext->ksym.kernel_btf_obj_fd;
+				} else { /* typeless ksyms or unresolved typed ksyms */
+					insn[0].imm = (__u32)ext->ksym.addr;
+					insn[1].imm = ext->ksym.addr >> 32;
+				}
+			}
+			break;
+		case RELO_EXTERN_CALL:
+			ext = &obj->externs[relo->ext_idx];
+			insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL;
+			if (ext->is_set) {
+				insn[0].imm = ext->ksym.kernel_btf_id;
+				insn[0].off = ext->ksym.btf_fd_idx;
+			} else { /* unresolved weak kfunc call */
+				poison_kfunc_call(prog, i, relo->insn_idx, insn,
+						  relo->ext_idx, ext);
+			}
+			break;
+		case RELO_SUBPROG_ADDR:
+			if (insn[0].src_reg != BPF_PSEUDO_FUNC) {
+				pr_warn("prog '%s': relo #%d: bad insn\n",
+					prog->name, i);
+				return -EINVAL;
+			}
+			/* handled already */
+			break;
+		case RELO_CALL:
+			/* handled already */
+			break;
+		case RELO_CORE:
+			/* will be handled by bpf_program_record_relos() */
+			break;
+		case RELO_INSN_ARRAY: {
+			int map_fd;
+
+			map_fd = create_jt_map(obj, prog, relo);
+			if (map_fd < 0) {
+				pr_warn("prog '%s': relo #%d: can't create jump table: sym_off %u\n",
+					prog->name, i, relo->sym_off);
+				return map_fd;
+			}
+			insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
+			insn->imm = map_fd;
+			insn->off = 0;
+		}
+			break;
+		default:
+			pr_warn("prog '%s': relo #%d: bad relo type %u\n",
+				prog->name, i, relo->type);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int adjust_prog_btf_ext_info(const struct bpf_object *obj,
+				    const struct bpf_program *prog,
+				    const struct btf_ext_info *ext_info,
+				    void **prog_info, __u32 *prog_rec_cnt,
+				    __u32 *prog_rec_sz)
+{
+	void *copy_start = NULL, *copy_end = NULL;
+	void *rec, *rec_end, *new_prog_info;
+	const struct btf_ext_info_sec *sec;
+	size_t old_sz, new_sz;
+	int i, sec_num, sec_idx, off_adj;
+
+	sec_num = 0;
+	for_each_btf_ext_sec(ext_info, sec) {
+		sec_idx = ext_info->sec_idxs[sec_num];
+		sec_num++;
+		if (prog->sec_idx != sec_idx)
+			continue;
+
+		for_each_btf_ext_rec(ext_info, sec, i, rec) {
+			__u32 insn_off = *(__u32 *)rec / BPF_INSN_SZ;
+
+			if (insn_off < prog->sec_insn_off)
+				continue;
+			if (insn_off >= prog->sec_insn_off + prog->sec_insn_cnt)
+				break;
+
+			if (!copy_start)
+				copy_start = rec;
+			copy_end = rec + ext_info->rec_size;
+		}
+
+		if (!copy_start)
+			return -ENOENT;
+
+		/* append func/line info of a given (sub-)program to the main
+		 * program func/line info
+		 */
+		old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size;
+		new_sz = old_sz + (copy_end - copy_start);
+		new_prog_info = realloc(*prog_info, new_sz);
+		if (!new_prog_info)
+			return -ENOMEM;
+		*prog_info = new_prog_info;
+		*prog_rec_cnt = new_sz / ext_info->rec_size;
+		memcpy(new_prog_info + old_sz, copy_start, copy_end - copy_start);
+
+		/* Kernel instruction offsets are in units of 8-byte
+		 * instructions, while .BTF.ext instruction offsets generated
+		 * by Clang are in units of bytes. So convert Clang offsets
+		 * into kernel offsets and adjust offset according to program
+		 * relocated position.
+		 */
+		off_adj = prog->sub_insn_off - prog->sec_insn_off;
+		rec = new_prog_info + old_sz;
+		rec_end = new_prog_info + new_sz;
+		for (; rec < rec_end; rec += ext_info->rec_size) {
+			__u32 *insn_off = rec;
+
+			*insn_off = *insn_off / BPF_INSN_SZ + off_adj;
+		}
+		*prog_rec_sz = ext_info->rec_size;
+		return 0;
+	}
+
+	return -ENOENT;
+}
+
+static int
+reloc_prog_func_and_line_info(const struct bpf_object *obj,
+			      struct bpf_program *main_prog,
+			      const struct bpf_program *prog)
+{
+	int err;
+
+	/* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't
+	 * support func/line info
+	 */
+	if (!obj->btf_ext || !kernel_supports(obj, FEAT_BTF_FUNC))
+		return 0;
+
+	/* only attempt func info relocation if main program's func_info
+	 * relocation was successful
+	 */
+	if (main_prog != prog && !main_prog->func_info)
+		goto line_info;
+
+	err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->func_info,
+				       &main_prog->func_info,
+				       &main_prog->func_info_cnt,
+				       &main_prog->func_info_rec_size);
+	if (err) {
+		if (err != -ENOENT) {
+			pr_warn("prog '%s': error relocating .BTF.ext function info: %s\n",
+				prog->name, errstr(err));
+			return err;
+		}
+		if (main_prog->func_info) {
+			/*
+			 * Some info has already been found but has problem
+			 * in the last btf_ext reloc. Must have to error out.
+			 */
+			pr_warn("prog '%s': missing .BTF.ext function info.\n", prog->name);
+			return err;
+		}
+		/* Have problem loading the very first info. Ignore the rest. */
+		pr_warn("prog '%s': missing .BTF.ext function info for the main program, skipping all of .BTF.ext func info.\n",
+			prog->name);
+	}
+
+line_info:
+	/* don't relocate line info if main program's relocation failed */
+	if (main_prog != prog && !main_prog->line_info)
+		return 0;
+
+	err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->line_info,
+				       &main_prog->line_info,
+				       &main_prog->line_info_cnt,
+				       &main_prog->line_info_rec_size);
+	if (err) {
+		if (err != -ENOENT) {
+			pr_warn("prog '%s': error relocating .BTF.ext line info: %s\n",
+				prog->name, errstr(err));
+			return err;
+		}
+		if (main_prog->line_info) {
+			/*
+			 * Some info has already been found but has problem
+			 * in the last btf_ext reloc. Must have to error out.
+			 */
+			pr_warn("prog '%s': missing .BTF.ext line info.\n", prog->name);
+			return err;
+		}
+		/* Have problem loading the very first info. Ignore the rest. */
+		pr_warn("prog '%s': missing .BTF.ext line info for the main program, skipping all of .BTF.ext line info.\n",
+			prog->name);
+	}
+	return 0;
+}
+
+static int cmp_relo_by_insn_idx(const void *key, const void *elem)
+{
+	size_t insn_idx = *(const size_t *)key;
+	const struct reloc_desc *relo = elem;
+
+	if (insn_idx == relo->insn_idx)
+		return 0;
+	return insn_idx < relo->insn_idx ? -1 : 1;
+}
+
+static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx)
+{
+	if (!prog->nr_reloc)
+		return NULL;
+	return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc,
+		       sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx);
+}
+
+static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_program *subprog)
+{
+	int new_cnt = main_prog->nr_reloc + subprog->nr_reloc;
+	struct reloc_desc *relos;
+	int i;
+
+	if (main_prog == subprog)
+		return 0;
+	relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos));
+	/* if new count is zero, reallocarray can return a valid NULL result;
+	 * in this case the previous pointer will be freed, so we *have to*
+	 * reassign old pointer to the new value (even if it's NULL)
+	 */
+	if (!relos && new_cnt)
+		return -ENOMEM;
+	if (subprog->nr_reloc)
+		memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc,
+		       sizeof(*relos) * subprog->nr_reloc);
+
+	for (i = main_prog->nr_reloc; i < new_cnt; i++)
+		relos[i].insn_idx += subprog->sub_insn_off;
+	/* After insn_idx adjustment the 'relos' array is still sorted
+	 * by insn_idx and doesn't break bsearch.
+	 */
+	main_prog->reloc_desc = relos;
+	main_prog->nr_reloc = new_cnt;
+	return 0;
+}
+
+static int save_subprog_offsets(struct bpf_program *main_prog, struct bpf_program *subprog)
+{
+	size_t size = sizeof(main_prog->subprogs[0]);
+	int cnt = main_prog->subprog_cnt;
+	void *tmp;
+
+	tmp = libbpf_reallocarray(main_prog->subprogs, cnt + 1, size);
+	if (!tmp)
+		return -ENOMEM;
+
+	main_prog->subprogs = tmp;
+	main_prog->subprogs[cnt].sec_insn_off = subprog->sec_insn_off;
+	main_prog->subprogs[cnt].sub_insn_off = subprog->sub_insn_off;
+	main_prog->subprog_cnt++;
+
+	return 0;
+}
+
+static int
+bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main_prog,
+				struct bpf_program *subprog)
+{
+	struct bpf_insn *insns;
+	size_t new_cnt;
+	int err;
+
+	subprog->sub_insn_off = main_prog->insns_cnt;
+
+	new_cnt = main_prog->insns_cnt + subprog->insns_cnt;
+	insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns));
+	if (!insns) {
+		pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name);
+		return -ENOMEM;
+	}
+	main_prog->insns = insns;
+	main_prog->insns_cnt = new_cnt;
+
+	memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns,
+	       subprog->insns_cnt * sizeof(*insns));
+
+	pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n",
+		 main_prog->name, subprog->insns_cnt, subprog->name);
+
+	/* The subprog insns are now appended. Append its relos too. */
+	err = append_subprog_relos(main_prog, subprog);
+	if (err)
+		return err;
+
+	err = save_subprog_offsets(main_prog, subprog);
+	if (err) {
+		pr_warn("prog '%s': failed to add subprog offsets: %s\n",
+			main_prog->name, errstr(err));
+		return err;
+	}
+
+	return 0;
+}
+
+static int
+bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog,
+		       struct bpf_program *prog)
+{
+	size_t sub_insn_idx, insn_idx;
+	struct bpf_program *subprog;
+	struct reloc_desc *relo;
+	struct bpf_insn *insn;
+	int err;
+
+	err = reloc_prog_func_and_line_info(obj, main_prog, prog);
+	if (err)
+		return err;
+
+	for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) {
+		insn = &main_prog->insns[prog->sub_insn_off + insn_idx];
+		if (!insn_is_subprog_call(insn) && !insn_is_pseudo_func(insn))
+			continue;
+
+		relo = find_prog_insn_relo(prog, insn_idx);
+		if (relo && relo->type == RELO_EXTERN_CALL)
+			/* kfunc relocations will be handled later
+			 * in bpf_object__relocate_data()
+			 */
+			continue;
+		if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) {
+			pr_warn("prog '%s': unexpected relo for insn #%zu, type %u\n",
+				prog->name, insn_idx, relo->type);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		if (relo) {
+			/* sub-program instruction index is a combination of
+			 * an offset of a symbol pointed to by relocation and
+			 * call instruction's imm field; for global functions,
+			 * call always has imm = -1, but for static functions
+			 * relocation is against STT_SECTION and insn->imm
+			 * points to a start of a static function
+			 *
+			 * for subprog addr relocation, the relo->sym_off + insn->imm is
+			 * the byte offset in the corresponding section.
+			 */
+			if (relo->type == RELO_CALL)
+				sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1;
+			else
+				sub_insn_idx = (relo->sym_off + insn->imm) / BPF_INSN_SZ;
+		} else if (insn_is_pseudo_func(insn)) {
+			/*
+			 * RELO_SUBPROG_ADDR relo is always emitted even if both
+			 * functions are in the same section, so it shouldn't reach here.
+			 */
+			pr_warn("prog '%s': missing subprog addr relo for insn #%zu\n",
+				prog->name, insn_idx);
+			return -LIBBPF_ERRNO__RELOC;
+		} else {
+			/* if subprogram call is to a static function within
+			 * the same ELF section, there won't be any relocation
+			 * emitted, but it also means there is no additional
+			 * offset necessary, insns->imm is relative to
+			 * instruction's original position within the section
+			 */
+			sub_insn_idx = prog->sec_insn_off + insn_idx + insn->imm + 1;
+		}
+
+		/* we enforce that sub-programs should be in .text section */
+		subprog = find_prog_by_sec_insn(obj, obj->efile.text_shndx, sub_insn_idx);
+		if (!subprog) {
+			pr_warn("prog '%s': no .text section found yet sub-program call exists\n",
+				prog->name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+
+		/* if it's the first call instruction calling into this
+		 * subprogram (meaning this subprog hasn't been processed
+		 * yet) within the context of current main program:
+		 *   - append it at the end of main program's instructions blog;
+		 *   - process is recursively, while current program is put on hold;
+		 *   - if that subprogram calls some other not yet processes
+		 *   subprogram, same thing will happen recursively until
+		 *   there are no more unprocesses subprograms left to append
+		 *   and relocate.
+		 */
+		if (subprog->sub_insn_off == 0) {
+			err = bpf_object__append_subprog_code(obj, main_prog, subprog);
+			if (err)
+				return err;
+			err = bpf_object__reloc_code(obj, main_prog, subprog);
+			if (err)
+				return err;
+		}
+
+		/* main_prog->insns memory could have been re-allocated, so
+		 * calculate pointer again
+		 */
+		insn = &main_prog->insns[prog->sub_insn_off + insn_idx];
+		/* calculate correct instruction position within current main
+		 * prog; each main prog can have a different set of
+		 * subprograms appended (potentially in different order as
+		 * well), so position of any subprog can be different for
+		 * different main programs
+		 */
+		insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1;
+
+		pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n",
+			 prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off);
+	}
+
+	return 0;
+}
+
+/*
+ * Relocate sub-program calls.
+ *
+ * Algorithm operates as follows. Each entry-point BPF program (referred to as
+ * main prog) is processed separately. For each subprog (non-entry functions,
+ * that can be called from either entry progs or other subprogs) gets their
+ * sub_insn_off reset to zero. This serves as indicator that this subprogram
+ * hasn't been yet appended and relocated within current main prog. Once its
+ * relocated, sub_insn_off will point at the position within current main prog
+ * where given subprog was appended. This will further be used to relocate all
+ * the call instructions jumping into this subprog.
+ *
+ * We start with main program and process all call instructions. If the call
+ * is into a subprog that hasn't been processed (i.e., subprog->sub_insn_off
+ * is zero), subprog instructions are appended at the end of main program's
+ * instruction array. Then main program is "put on hold" while we recursively
+ * process newly appended subprogram. If that subprogram calls into another
+ * subprogram that hasn't been appended, new subprogram is appended again to
+ * the *main* prog's instructions (subprog's instructions are always left
+ * untouched, as they need to be in unmodified state for subsequent main progs
+ * and subprog instructions are always sent only as part of a main prog) and
+ * the process continues recursively. Once all the subprogs called from a main
+ * prog or any of its subprogs are appended (and relocated), all their
+ * positions within finalized instructions array are known, so it's easy to
+ * rewrite call instructions with correct relative offsets, corresponding to
+ * desired target subprog.
+ *
+ * Its important to realize that some subprogs might not be called from some
+ * main prog and any of its called/used subprogs. Those will keep their
+ * subprog->sub_insn_off as zero at all times and won't be appended to current
+ * main prog and won't be relocated within the context of current main prog.
+ * They might still be used from other main progs later.
+ *
+ * Visually this process can be shown as below. Suppose we have two main
+ * programs mainA and mainB and BPF object contains three subprogs: subA,
+ * subB, and subC. mainA calls only subA, mainB calls only subC, but subA and
+ * subC both call subB:
+ *
+ *        +--------+ +-------+
+ *        |        v v       |
+ *     +--+---+ +--+-+-+ +---+--+
+ *     | subA | | subB | | subC |
+ *     +--+---+ +------+ +---+--+
+ *        ^                  ^
+ *        |                  |
+ *    +---+-------+   +------+----+
+ *    |   mainA   |   |   mainB   |
+ *    +-----------+   +-----------+
+ *
+ * We'll start relocating mainA, will find subA, append it and start
+ * processing sub A recursively:
+ *
+ *    +-----------+------+
+ *    |   mainA   | subA |
+ *    +-----------+------+
+ *
+ * At this point we notice that subB is used from subA, so we append it and
+ * relocate (there are no further subcalls from subB):
+ *
+ *    +-----------+------+------+
+ *    |   mainA   | subA | subB |
+ *    +-----------+------+------+
+ *
+ * At this point, we relocate subA calls, then go one level up and finish with
+ * relocation mainA calls. mainA is done.
+ *
+ * For mainB process is similar but results in different order. We start with
+ * mainB and skip subA and subB, as mainB never calls them (at least
+ * directly), but we see subC is needed, so we append and start processing it:
+ *
+ *    +-----------+------+
+ *    |   mainB   | subC |
+ *    +-----------+------+
+ * Now we see subC needs subB, so we go back to it, append and relocate it:
+ *
+ *    +-----------+------+------+
+ *    |   mainB   | subC | subB |
+ *    +-----------+------+------+
+ *
+ * At this point we unwind recursion, relocate calls in subC, then in mainB.
+ */
+static int
+bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog)
+{
+	struct bpf_program *subprog;
+	int i, err;
+
+	/* mark all subprogs as not relocated (yet) within the context of
+	 * current main program
+	 */
+	for (i = 0; i < obj->nr_programs; i++) {
+		subprog = &obj->programs[i];
+		if (!prog_is_subprog(obj, subprog))
+			continue;
+
+		subprog->sub_insn_off = 0;
+	}
+
+	err = bpf_object__reloc_code(obj, prog, prog);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static void
+bpf_object__free_relocs(struct bpf_object *obj)
+{
+	struct bpf_program *prog;
+	int i;
+
+	/* free up relocation descriptors */
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		zfree(&prog->reloc_desc);
+		prog->nr_reloc = 0;
+	}
+}
+
+static int cmp_relocs(const void *_a, const void *_b)
+{
+	const struct reloc_desc *a = _a;
+	const struct reloc_desc *b = _b;
+
+	if (a->insn_idx != b->insn_idx)
+		return a->insn_idx < b->insn_idx ? -1 : 1;
+
+	/* no two relocations should have the same insn_idx, but ... */
+	if (a->type != b->type)
+		return a->type < b->type ? -1 : 1;
+
+	return 0;
+}
+
+static void bpf_object__sort_relos(struct bpf_object *obj)
+{
+	int i;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		struct bpf_program *p = &obj->programs[i];
+
+		if (!p->nr_reloc)
+			continue;
+
+		qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs);
+	}
+}
+
+static int bpf_prog_assign_exc_cb(struct bpf_object *obj, struct bpf_program *prog)
+{
+	const char *str = "exception_callback:";
+	size_t pfx_len = strlen(str);
+	int i, j, n;
+
+	if (!obj->btf || !kernel_supports(obj, FEAT_BTF_DECL_TAG))
+		return 0;
+
+	n = btf__type_cnt(obj->btf);
+	for (i = 1; i < n; i++) {
+		const char *name;
+		struct btf_type *t;
+
+		t = btf_type_by_id(obj->btf, i);
+		if (!btf_is_decl_tag(t) || btf_decl_tag(t)->component_idx != -1)
+			continue;
+
+		name = btf__str_by_offset(obj->btf, t->name_off);
+		if (strncmp(name, str, pfx_len) != 0)
+			continue;
+
+		t = btf_type_by_id(obj->btf, t->type);
+		if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) {
+			pr_warn("prog '%s': exception_callback:<value> decl tag not applied to the main program\n",
+				prog->name);
+			return -EINVAL;
+		}
+		if (strcmp(prog->name, btf__str_by_offset(obj->btf, t->name_off)) != 0)
+			continue;
+		/* Multiple callbacks are specified for the same prog,
+		 * the verifier will eventually return an error for this
+		 * case, hence simply skip appending a subprog.
+		 */
+		if (prog->exception_cb_idx >= 0) {
+			prog->exception_cb_idx = -1;
+			break;
+		}
+
+		name += pfx_len;
+		if (str_is_empty(name)) {
+			pr_warn("prog '%s': exception_callback:<value> decl tag contains empty value\n",
+				prog->name);
+			return -EINVAL;
+		}
+
+		for (j = 0; j < obj->nr_programs; j++) {
+			struct bpf_program *subprog = &obj->programs[j];
+
+			if (!prog_is_subprog(obj, subprog))
+				continue;
+			if (strcmp(name, subprog->name) != 0)
+				continue;
+			/* Enforce non-hidden, as from verifier point of
+			 * view it expects global functions, whereas the
+			 * mark_btf_static fixes up linkage as static.
+			 */
+			if (!subprog->sym_global || subprog->mark_btf_static) {
+				pr_warn("prog '%s': exception callback %s must be a global non-hidden function\n",
+					prog->name, subprog->name);
+				return -EINVAL;
+			}
+			/* Let's see if we already saw a static exception callback with the same name */
+			if (prog->exception_cb_idx >= 0) {
+				pr_warn("prog '%s': multiple subprogs with same name as exception callback '%s'\n",
+					prog->name, subprog->name);
+				return -EINVAL;
+			}
+			prog->exception_cb_idx = j;
+			break;
+		}
+
+		if (prog->exception_cb_idx >= 0)
+			continue;
+
+		pr_warn("prog '%s': cannot find exception callback '%s'\n", prog->name, name);
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static struct {
+	enum bpf_prog_type prog_type;
+	const char *ctx_name;
+} global_ctx_map[] = {
+	{ BPF_PROG_TYPE_CGROUP_DEVICE,           "bpf_cgroup_dev_ctx" },
+	{ BPF_PROG_TYPE_CGROUP_SKB,              "__sk_buff" },
+	{ BPF_PROG_TYPE_CGROUP_SOCK,             "bpf_sock" },
+	{ BPF_PROG_TYPE_CGROUP_SOCK_ADDR,        "bpf_sock_addr" },
+	{ BPF_PROG_TYPE_CGROUP_SOCKOPT,          "bpf_sockopt" },
+	{ BPF_PROG_TYPE_CGROUP_SYSCTL,           "bpf_sysctl" },
+	{ BPF_PROG_TYPE_FLOW_DISSECTOR,          "__sk_buff" },
+	{ BPF_PROG_TYPE_KPROBE,                  "bpf_user_pt_regs_t" },
+	{ BPF_PROG_TYPE_LWT_IN,                  "__sk_buff" },
+	{ BPF_PROG_TYPE_LWT_OUT,                 "__sk_buff" },
+	{ BPF_PROG_TYPE_LWT_SEG6LOCAL,           "__sk_buff" },
+	{ BPF_PROG_TYPE_LWT_XMIT,                "__sk_buff" },
+	{ BPF_PROG_TYPE_NETFILTER,               "bpf_nf_ctx" },
+	{ BPF_PROG_TYPE_PERF_EVENT,              "bpf_perf_event_data" },
+	{ BPF_PROG_TYPE_RAW_TRACEPOINT,          "bpf_raw_tracepoint_args" },
+	{ BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, "bpf_raw_tracepoint_args" },
+	{ BPF_PROG_TYPE_SCHED_ACT,               "__sk_buff" },
+	{ BPF_PROG_TYPE_SCHED_CLS,               "__sk_buff" },
+	{ BPF_PROG_TYPE_SK_LOOKUP,               "bpf_sk_lookup" },
+	{ BPF_PROG_TYPE_SK_MSG,                  "sk_msg_md" },
+	{ BPF_PROG_TYPE_SK_REUSEPORT,            "sk_reuseport_md" },
+	{ BPF_PROG_TYPE_SK_SKB,                  "__sk_buff" },
+	{ BPF_PROG_TYPE_SOCK_OPS,                "bpf_sock_ops" },
+	{ BPF_PROG_TYPE_SOCKET_FILTER,           "__sk_buff" },
+	{ BPF_PROG_TYPE_XDP,                     "xdp_md" },
+	/* all other program types don't have "named" context structs */
+};
+
+/* forward declarations for arch-specific underlying types of bpf_user_pt_regs_t typedef,
+ * for below __builtin_types_compatible_p() checks;
+ * with this approach we don't need any extra arch-specific #ifdef guards
+ */
+struct pt_regs;
+struct user_pt_regs;
+struct user_regs_struct;
+
+static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_program *prog,
+				     const char *subprog_name, int arg_idx,
+				     int arg_type_id, const char *ctx_name)
+{
+	const struct btf_type *t;
+	const char *tname;
+
+	/* check if existing parameter already matches verifier expectations */
+	t = skip_mods_and_typedefs(btf, arg_type_id, NULL);
+	if (!btf_is_ptr(t))
+		goto out_warn;
+
+	/* typedef bpf_user_pt_regs_t is a special PITA case, valid for kprobe
+	 * and perf_event programs, so check this case early on and forget
+	 * about it for subsequent checks
+	 */
+	while (btf_is_mod(t))
+		t = btf__type_by_id(btf, t->type);
+	if (btf_is_typedef(t) &&
+	    (prog->type == BPF_PROG_TYPE_KPROBE || prog->type == BPF_PROG_TYPE_PERF_EVENT)) {
+		tname = btf__str_by_offset(btf, t->name_off) ?: "<anon>";
+		if (strcmp(tname, "bpf_user_pt_regs_t") == 0)
+			return false; /* canonical type for kprobe/perf_event */
+	}
+
+	/* now we can ignore typedefs moving forward */
+	t = skip_mods_and_typedefs(btf, t->type, NULL);
+
+	/* if it's `void *`, definitely fix up BTF info */
+	if (btf_is_void(t))
+		return true;
+
+	/* if it's already proper canonical type, no need to fix up */
+	tname = btf__str_by_offset(btf, t->name_off) ?: "<anon>";
+	if (btf_is_struct(t) && strcmp(tname, ctx_name) == 0)
+		return false;
+
+	/* special cases */
+	switch (prog->type) {
+	case BPF_PROG_TYPE_KPROBE:
+		/* `struct pt_regs *` is expected, but we need to fix up */
+		if (btf_is_struct(t) && strcmp(tname, "pt_regs") == 0)
+			return true;
+		break;
+	case BPF_PROG_TYPE_PERF_EVENT:
+		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) &&
+		    btf_is_struct(t) && strcmp(tname, "pt_regs") == 0)
+			return true;
+		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) &&
+		    btf_is_struct(t) && strcmp(tname, "user_pt_regs") == 0)
+			return true;
+		if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) &&
+		    btf_is_struct(t) && strcmp(tname, "user_regs_struct") == 0)
+			return true;
+		break;
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+		/* allow u64* as ctx */
+		if (btf_is_int(t) && t->size == 8)
+			return true;
+		break;
+	default:
+		break;
+	}
+
+out_warn:
+	pr_warn("prog '%s': subprog '%s' arg#%d is expected to be of `struct %s *` type\n",
+		prog->name, subprog_name, arg_idx, ctx_name);
+	return false;
+}
+
+static int clone_func_btf_info(struct btf *btf, int orig_fn_id, struct bpf_program *prog)
+{
+	int fn_id, fn_proto_id, ret_type_id, orig_proto_id;
+	int i, err, arg_cnt, fn_name_off, linkage;
+	struct btf_type *fn_t, *fn_proto_t, *t;
+	struct btf_param *p;
+
+	/* caller already validated FUNC -> FUNC_PROTO validity */
+	fn_t = btf_type_by_id(btf, orig_fn_id);
+	fn_proto_t = btf_type_by_id(btf, fn_t->type);
+
+	/* Note that each btf__add_xxx() operation invalidates
+	 * all btf_type and string pointers, so we need to be
+	 * very careful when cloning BTF types. BTF type
+	 * pointers have to be always refetched. And to avoid
+	 * problems with invalidated string pointers, we
+	 * add empty strings initially, then just fix up
+	 * name_off offsets in place. Offsets are stable for
+	 * existing strings, so that works out.
+	 */
+	fn_name_off = fn_t->name_off; /* we are about to invalidate fn_t */
+	linkage = btf_func_linkage(fn_t);
+	orig_proto_id = fn_t->type; /* original FUNC_PROTO ID */
+	ret_type_id = fn_proto_t->type; /* fn_proto_t will be invalidated */
+	arg_cnt = btf_vlen(fn_proto_t);
+
+	/* clone FUNC_PROTO and its params */
+	fn_proto_id = btf__add_func_proto(btf, ret_type_id);
+	if (fn_proto_id < 0)
+		return -EINVAL;
+
+	for (i = 0; i < arg_cnt; i++) {
+		int name_off;
+
+		/* copy original parameter data */
+		t = btf_type_by_id(btf, orig_proto_id);
+		p = &btf_params(t)[i];
+		name_off = p->name_off;
+
+		err = btf__add_func_param(btf, "", p->type);
+		if (err)
+			return err;
+
+		fn_proto_t = btf_type_by_id(btf, fn_proto_id);
+		p = &btf_params(fn_proto_t)[i];
+		p->name_off = name_off; /* use remembered str offset */
+	}
+
+	/* clone FUNC now, btf__add_func() enforces non-empty name, so use
+	 * entry program's name as a placeholder, which we replace immediately
+	 * with original name_off
+	 */
+	fn_id = btf__add_func(btf, prog->name, linkage, fn_proto_id);
+	if (fn_id < 0)
+		return -EINVAL;
+
+	fn_t = btf_type_by_id(btf, fn_id);
+	fn_t->name_off = fn_name_off; /* reuse original string */
+
+	return fn_id;
+}
+
+/* Check if main program or global subprog's function prototype has `arg:ctx`
+ * argument tags, and, if necessary, substitute correct type to match what BPF
+ * verifier would expect, taking into account specific program type. This
+ * allows to support __arg_ctx tag transparently on old kernels that don't yet
+ * have a native support for it in the verifier, making user's life much
+ * easier.
+ */
+static int bpf_program_fixup_func_info(struct bpf_object *obj, struct bpf_program *prog)
+{
+	const char *ctx_name = NULL, *ctx_tag = "arg:ctx", *fn_name;
+	struct bpf_func_info_min *func_rec;
+	struct btf_type *fn_t, *fn_proto_t;
+	struct btf *btf = obj->btf;
+	const struct btf_type *t;
+	struct btf_param *p;
+	int ptr_id = 0, struct_id, tag_id, orig_fn_id;
+	int i, n, arg_idx, arg_cnt, err, rec_idx;
+	int *orig_ids;
+
+	/* no .BTF.ext, no problem */
+	if (!obj->btf_ext || !prog->func_info)
+		return 0;
+
+	/* don't do any fix ups if kernel natively supports __arg_ctx */
+	if (kernel_supports(obj, FEAT_ARG_CTX_TAG))
+		return 0;
+
+	/* some BPF program types just don't have named context structs, so
+	 * this fallback mechanism doesn't work for them
+	 */
+	for (i = 0; i < ARRAY_SIZE(global_ctx_map); i++) {
+		if (global_ctx_map[i].prog_type != prog->type)
+			continue;
+		ctx_name = global_ctx_map[i].ctx_name;
+		break;
+	}
+	if (!ctx_name)
+		return 0;
+
+	/* remember original func BTF IDs to detect if we already cloned them */
+	orig_ids = calloc(prog->func_info_cnt, sizeof(*orig_ids));
+	if (!orig_ids)
+		return -ENOMEM;
+	for (i = 0; i < prog->func_info_cnt; i++) {
+		func_rec = prog->func_info + prog->func_info_rec_size * i;
+		orig_ids[i] = func_rec->type_id;
+	}
+
+	/* go through each DECL_TAG with "arg:ctx" and see if it points to one
+	 * of our subprogs; if yes and subprog is global and needs adjustment,
+	 * clone and adjust FUNC -> FUNC_PROTO combo
+	 */
+	for (i = 1, n = btf__type_cnt(btf); i < n; i++) {
+		/* only DECL_TAG with "arg:ctx" value are interesting */
+		t = btf__type_by_id(btf, i);
+		if (!btf_is_decl_tag(t))
+			continue;
+		if (strcmp(btf__str_by_offset(btf, t->name_off), ctx_tag) != 0)
+			continue;
+
+		/* only global funcs need adjustment, if at all */
+		orig_fn_id = t->type;
+		fn_t = btf_type_by_id(btf, orig_fn_id);
+		if (!btf_is_func(fn_t) || btf_func_linkage(fn_t) != BTF_FUNC_GLOBAL)
+			continue;
+
+		/* sanity check FUNC -> FUNC_PROTO chain, just in case */
+		fn_proto_t = btf_type_by_id(btf, fn_t->type);
+		if (!fn_proto_t || !btf_is_func_proto(fn_proto_t))
+			continue;
+
+		/* find corresponding func_info record */
+		func_rec = NULL;
+		for (rec_idx = 0; rec_idx < prog->func_info_cnt; rec_idx++) {
+			if (orig_ids[rec_idx] == t->type) {
+				func_rec = prog->func_info + prog->func_info_rec_size * rec_idx;
+				break;
+			}
+		}
+		/* current main program doesn't call into this subprog */
+		if (!func_rec)
+			continue;
+
+		/* some more sanity checking of DECL_TAG */
+		arg_cnt = btf_vlen(fn_proto_t);
+		arg_idx = btf_decl_tag(t)->component_idx;
+		if (arg_idx < 0 || arg_idx >= arg_cnt)
+			continue;
+
+		/* check if we should fix up argument type */
+		p = &btf_params(fn_proto_t)[arg_idx];
+		fn_name = btf__str_by_offset(btf, fn_t->name_off) ?: "<anon>";
+		if (!need_func_arg_type_fixup(btf, prog, fn_name, arg_idx, p->type, ctx_name))
+			continue;
+
+		/* clone fn/fn_proto, unless we already did it for another arg */
+		if (func_rec->type_id == orig_fn_id) {
+			int fn_id;
+
+			fn_id = clone_func_btf_info(btf, orig_fn_id, prog);
+			if (fn_id < 0) {
+				err = fn_id;
+				goto err_out;
+			}
+
+			/* point func_info record to a cloned FUNC type */
+			func_rec->type_id = fn_id;
+		}
+
+		/* create PTR -> STRUCT type chain to mark PTR_TO_CTX argument;
+		 * we do it just once per main BPF program, as all global
+		 * funcs share the same program type, so need only PTR ->
+		 * STRUCT type chain
+		 */
+		if (ptr_id == 0) {
+			struct_id = btf__add_struct(btf, ctx_name, 0);
+			ptr_id = btf__add_ptr(btf, struct_id);
+			if (ptr_id < 0 || struct_id < 0) {
+				err = -EINVAL;
+				goto err_out;
+			}
+		}
+
+		/* for completeness, clone DECL_TAG and point it to cloned param */
+		tag_id = btf__add_decl_tag(btf, ctx_tag, func_rec->type_id, arg_idx);
+		if (tag_id < 0) {
+			err = -EINVAL;
+			goto err_out;
+		}
+
+		/* all the BTF manipulations invalidated pointers, refetch them */
+		fn_t = btf_type_by_id(btf, func_rec->type_id);
+		fn_proto_t = btf_type_by_id(btf, fn_t->type);
+
+		/* fix up type ID pointed to by param */
+		p = &btf_params(fn_proto_t)[arg_idx];
+		p->type = ptr_id;
+	}
+
+	free(orig_ids);
+	return 0;
+err_out:
+	free(orig_ids);
+	return err;
+}
+
+static int bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
+{
+	struct bpf_program *prog;
+	size_t i, j;
+	int err;
+
+	if (obj->btf_ext) {
+		err = bpf_object__relocate_core(obj, targ_btf_path);
+		if (err) {
+			pr_warn("failed to perform CO-RE relocations: %s\n",
+				errstr(err));
+			return err;
+		}
+		bpf_object__sort_relos(obj);
+	}
+
+	/* place globals at the end of the arena (if supported) */
+	if (obj->arena_map_idx >= 0 && kernel_supports(obj, FEAT_LDIMM64_FULL_RANGE_OFF)) {
+		struct bpf_map *arena_map = &obj->maps[obj->arena_map_idx];
+
+		obj->arena_data_off = bpf_map_mmap_sz(arena_map) -
+				      roundup(obj->arena_data_sz, sysconf(_SC_PAGE_SIZE));
+	}
+
+	/* Before relocating calls pre-process relocations and mark
+	 * few ld_imm64 instructions that points to subprogs.
+	 * Otherwise bpf_object__reloc_code() later would have to consider
+	 * all ld_imm64 insns as relocation candidates. That would
+	 * reduce relocation speed, since amount of find_prog_insn_relo()
+	 * would increase and most of them will fail to find a relo.
+	 */
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		for (j = 0; j < prog->nr_reloc; j++) {
+			struct reloc_desc *relo = &prog->reloc_desc[j];
+			struct bpf_insn *insn = &prog->insns[relo->insn_idx];
+
+			/* mark the insn, so it's recognized by insn_is_pseudo_func() */
+			if (relo->type == RELO_SUBPROG_ADDR)
+				insn[0].src_reg = BPF_PSEUDO_FUNC;
+		}
+	}
+
+	/* relocate subprogram calls and append used subprograms to main
+	 * programs; each copy of subprogram code needs to be relocated
+	 * differently for each main program, because its code location might
+	 * have changed.
+	 * Append subprog relos to main programs to allow data relos to be
+	 * processed after text is completely relocated.
+	 */
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		/* sub-program's sub-calls are relocated within the context of
+		 * its main program only
+		 */
+		if (prog_is_subprog(obj, prog))
+			continue;
+		if (!prog->autoload)
+			continue;
+
+		err = bpf_object__relocate_calls(obj, prog);
+		if (err) {
+			pr_warn("prog '%s': failed to relocate calls: %s\n",
+				prog->name, errstr(err));
+			return err;
+		}
+
+		err = bpf_prog_assign_exc_cb(obj, prog);
+		if (err)
+			return err;
+		/* Now, also append exception callback if it has not been done already. */
+		if (prog->exception_cb_idx >= 0) {
+			struct bpf_program *subprog = &obj->programs[prog->exception_cb_idx];
+
+			/* Calling exception callback directly is disallowed, which the
+			 * verifier will reject later. In case it was processed already,
+			 * we can skip this step, otherwise for all other valid cases we
+			 * have to append exception callback now.
+			 */
+			if (subprog->sub_insn_off == 0) {
+				err = bpf_object__append_subprog_code(obj, prog, subprog);
+				if (err)
+					return err;
+				err = bpf_object__reloc_code(obj, prog, subprog);
+				if (err)
+					return err;
+			}
+		}
+	}
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		if (prog_is_subprog(obj, prog))
+			continue;
+		if (!prog->autoload)
+			continue;
+
+		/* Process data relos for main programs */
+		err = bpf_object__relocate_data(obj, prog);
+		if (err) {
+			pr_warn("prog '%s': failed to relocate data references: %s\n",
+				prog->name, errstr(err));
+			return err;
+		}
+
+		/* Fix up .BTF.ext information, if necessary */
+		err = bpf_program_fixup_func_info(obj, prog);
+		if (err) {
+			pr_warn("prog '%s': failed to perform .BTF.ext fix ups: %s\n",
+				prog->name, errstr(err));
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
+					    Elf64_Shdr *shdr, Elf_Data *data);
+
+static int bpf_object__collect_map_relos(struct bpf_object *obj,
+					 Elf64_Shdr *shdr, Elf_Data *data)
+{
+	const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *);
+	int i, j, nrels, new_sz;
+	const struct btf_var_secinfo *vi = NULL;
+	const struct btf_type *sec, *var, *def;
+	struct bpf_map *map = NULL, *targ_map = NULL;
+	struct bpf_program *targ_prog = NULL;
+	bool is_prog_array, is_map_in_map;
+	const struct btf_member *member;
+	const char *name, *mname, *type;
+	unsigned int moff;
+	Elf64_Sym *sym;
+	Elf64_Rel *rel;
+	void *tmp;
+
+	if (!obj->efile.btf_maps_sec_btf_id || !obj->btf)
+		return -EINVAL;
+	sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id);
+	if (!sec)
+		return -EINVAL;
+
+	nrels = shdr->sh_size / shdr->sh_entsize;
+	for (i = 0; i < nrels; i++) {
+		rel = elf_rel_by_idx(data, i);
+		if (!rel) {
+			pr_warn(".maps relo #%d: failed to get ELF relo\n", i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info));
+		if (!sym) {
+			pr_warn(".maps relo #%d: symbol %zx not found\n",
+				i, (size_t)ELF64_R_SYM(rel->r_info));
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+		name = elf_sym_str(obj, sym->st_name) ?: "<?>";
+
+		pr_debug(".maps relo #%d: for %zd value %zu rel->r_offset %zu name %u ('%s')\n",
+			 i, (ssize_t)(rel->r_info >> 32), (size_t)sym->st_value,
+			 (size_t)rel->r_offset, sym->st_name, name);
+
+		for (j = 0; j < obj->nr_maps; j++) {
+			map = &obj->maps[j];
+			if (map->sec_idx != obj->efile.btf_maps_shndx)
+				continue;
+
+			vi = btf_var_secinfos(sec) + map->btf_var_idx;
+			if (vi->offset <= rel->r_offset &&
+			    rel->r_offset + bpf_ptr_sz <= vi->offset + vi->size)
+				break;
+		}
+		if (j == obj->nr_maps) {
+			pr_warn(".maps relo #%d: cannot find map '%s' at rel->r_offset %zu\n",
+				i, name, (size_t)rel->r_offset);
+			return -EINVAL;
+		}
+
+		is_map_in_map = bpf_map_type__is_map_in_map(map->def.type);
+		is_prog_array = map->def.type == BPF_MAP_TYPE_PROG_ARRAY;
+		type = is_map_in_map ? "map" : "prog";
+		if (is_map_in_map) {
+			if (sym->st_shndx != obj->efile.btf_maps_shndx) {
+				pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
+					i, name);
+				return -LIBBPF_ERRNO__RELOC;
+			}
+			if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
+			    map->def.key_size != sizeof(int)) {
+				pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
+					i, map->name, sizeof(int));
+				return -EINVAL;
+			}
+			targ_map = bpf_object__find_map_by_name(obj, name);
+			if (!targ_map) {
+				pr_warn(".maps relo #%d: '%s' isn't a valid map reference\n",
+					i, name);
+				return -ESRCH;
+			}
+		} else if (is_prog_array) {
+			targ_prog = bpf_object__find_program_by_name(obj, name);
+			if (!targ_prog) {
+				pr_warn(".maps relo #%d: '%s' isn't a valid program reference\n",
+					i, name);
+				return -ESRCH;
+			}
+			if (targ_prog->sec_idx != sym->st_shndx ||
+			    targ_prog->sec_insn_off * 8 != sym->st_value ||
+			    prog_is_subprog(obj, targ_prog)) {
+				pr_warn(".maps relo #%d: '%s' isn't an entry-point program\n",
+					i, name);
+				return -LIBBPF_ERRNO__RELOC;
+			}
+		} else {
+			return -EINVAL;
+		}
+
+		var = btf__type_by_id(obj->btf, vi->type);
+		def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
+		if (btf_vlen(def) == 0)
+			return -EINVAL;
+		member = btf_members(def) + btf_vlen(def) - 1;
+		mname = btf__name_by_offset(obj->btf, member->name_off);
+		if (strcmp(mname, "values"))
+			return -EINVAL;
+
+		moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8;
+		if (rel->r_offset - vi->offset < moff)
+			return -EINVAL;
+
+		moff = rel->r_offset - vi->offset - moff;
+		/* here we use BPF pointer size, which is always 64 bit, as we
+		 * are parsing ELF that was built for BPF target
+		 */
+		if (moff % bpf_ptr_sz)
+			return -EINVAL;
+		moff /= bpf_ptr_sz;
+		if (moff >= map->init_slots_sz) {
+			new_sz = moff + 1;
+			tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz);
+			if (!tmp)
+				return -ENOMEM;
+			map->init_slots = tmp;
+			memset(map->init_slots + map->init_slots_sz, 0,
+			       (new_sz - map->init_slots_sz) * host_ptr_sz);
+			map->init_slots_sz = new_sz;
+		}
+		map->init_slots[moff] = is_map_in_map ? (void *)targ_map : (void *)targ_prog;
+
+		pr_debug(".maps relo #%d: map '%s' slot [%u] points to %s '%s'\n",
+			 i, map->name, moff, type, name);
+	}
+
+	return 0;
+}
+
+static int bpf_object__collect_relos(struct bpf_object *obj)
+{
+	int i, err;
+
+	for (i = 0; i < obj->efile.sec_cnt; i++) {
+		struct elf_sec_desc *sec_desc = &obj->efile.secs[i];
+		Elf64_Shdr *shdr;
+		Elf_Data *data;
+		int idx;
+
+		if (sec_desc->sec_type != SEC_RELO)
+			continue;
+
+		shdr = sec_desc->shdr;
+		data = sec_desc->data;
+		idx = shdr->sh_info;
+
+		if (shdr->sh_type != SHT_REL || idx < 0 || idx >= obj->efile.sec_cnt) {
+			pr_warn("internal error at %d\n", __LINE__);
+			return -LIBBPF_ERRNO__INTERNAL;
+		}
+
+		if (obj->efile.secs[idx].sec_type == SEC_ST_OPS)
+			err = bpf_object__collect_st_ops_relos(obj, shdr, data);
+		else if (idx == obj->efile.btf_maps_shndx)
+			err = bpf_object__collect_map_relos(obj, shdr, data);
+		else
+			err = bpf_object__collect_prog_relos(obj, shdr, data);
+		if (err)
+			return err;
+	}
+
+	bpf_object__sort_relos(obj);
+	return 0;
+}
+
+static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id)
+{
+	if (BPF_CLASS(insn->code) == BPF_JMP &&
+	    BPF_OP(insn->code) == BPF_CALL &&
+	    BPF_SRC(insn->code) == BPF_K &&
+	    insn->src_reg == 0 &&
+	    insn->dst_reg == 0) {
+		    *func_id = insn->imm;
+		    return true;
+	}
+	return false;
+}
+
+static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program *prog)
+{
+	struct bpf_insn *insn = prog->insns;
+	enum bpf_func_id func_id;
+	int i;
+
+	if (obj->gen_loader)
+		return 0;
+
+	for (i = 0; i < prog->insns_cnt; i++, insn++) {
+		if (!insn_is_helper_call(insn, &func_id))
+			continue;
+
+		/* on kernels that don't yet support
+		 * bpf_probe_read_{kernel,user}[_str] helpers, fall back
+		 * to bpf_probe_read() which works well for old kernels
+		 */
+		switch (func_id) {
+		case BPF_FUNC_probe_read_kernel:
+		case BPF_FUNC_probe_read_user:
+			if (!kernel_supports(obj, FEAT_PROBE_READ_KERN))
+				insn->imm = BPF_FUNC_probe_read;
+			break;
+		case BPF_FUNC_probe_read_kernel_str:
+		case BPF_FUNC_probe_read_user_str:
+			if (!kernel_supports(obj, FEAT_PROBE_READ_KERN))
+				insn->imm = BPF_FUNC_probe_read_str;
+			break;
+		default:
+			break;
+		}
+	}
+	return 0;
+}
+
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name,
+				     int *btf_obj_fd, int *btf_type_id);
+
+static inline bool is_tracing_multi(enum bpf_attach_type type)
+{
+	return type == BPF_TRACE_FENTRY_MULTI || type == BPF_TRACE_FEXIT_MULTI ||
+	       type == BPF_TRACE_FSESSION_MULTI;
+}
+
+static const struct module_btf *find_attach_module(struct bpf_object *obj, const char *attach)
+{
+	const char *sep, *mod_name = NULL;
+	int i, mod_len, err;
+
+	/*
+	 * We expect attach string in the form of either
+	 * - function_pattern or
+	 * - <module>:function_pattern
+	 */
+	sep = strchr(attach, ':');
+	if (sep) {
+		mod_name = attach;
+		mod_len = sep - mod_name;
+	}
+	if (!mod_name)
+		return NULL;
+
+	err = load_module_btfs(obj);
+	if (err)
+		return NULL;
+
+	for (i = 0; i < obj->btf_module_cnt; i++) {
+		const struct module_btf *mod = &obj->btf_modules[i];
+
+		if (strncmp(mod->name, mod_name, mod_len) == 0 && mod->name[mod_len] == '\0')
+			return mod;
+	}
+	return NULL;
+}
+
+static int tracing_multi_mod_fd(struct bpf_program *prog, int *btf_obj_fd)
+{
+	const char *attach_name, *sep;
+	const struct module_btf *mod;
+
+	*btf_obj_fd = 0;
+	attach_name = strchr(prog->sec_name, '/');
+
+	/* Program with no details in spec, using kernel btf. */
+	if (!attach_name)
+		return 0;
+
+	/* Program with no module section, using kernel btf. */
+	sep = strchr(++attach_name, ':');
+	if (!sep)
+		return 0;
+
+	/* Program with module specified, get its btf fd. */
+	mod = find_attach_module(prog->obj, attach_name);
+	if (!mod)
+		return -EINVAL;
+
+	*btf_obj_fd = mod->fd;
+	return 0;
+}
+
+/* this is called as prog->sec_def->prog_prepare_load_fn for libbpf-supported sec_defs */
+static int libbpf_prepare_prog_load(struct bpf_program *prog,
+				    struct bpf_prog_load_opts *opts, long cookie)
+{
+	enum sec_def_flags def = cookie;
+
+	/* old kernels might not support specifying expected_attach_type */
+	if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE))
+		opts->expected_attach_type = 0;
+
+	if (def & SEC_SLEEPABLE)
+		opts->prog_flags |= BPF_F_SLEEPABLE;
+
+	if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_FRAGS))
+		opts->prog_flags |= BPF_F_XDP_HAS_FRAGS;
+
+	/* special check for usdt to use uprobe_multi link */
+	if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) {
+		/* for BPF_TRACE_UPROBE_MULTI, user might want to query expected_attach_type
+		 * in prog, and expected_attach_type we set in kernel is from opts, so we
+		 * update both.
+		 */
+		prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI;
+		opts->expected_attach_type = BPF_TRACE_UPROBE_MULTI;
+	}
+
+	if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) {
+		int btf_obj_fd = 0, btf_type_id = 0, err;
+		const char *attach_name;
+
+		attach_name = strchr(prog->sec_name, '/');
+		if (!attach_name) {
+			/* if BPF program is annotated with just SEC("fentry")
+			 * (or similar) without declaratively specifying
+			 * target, then it is expected that target will be
+			 * specified with bpf_program__set_attach_target() at
+			 * runtime before BPF object load step. If not, then
+			 * there is nothing to load into the kernel as BPF
+			 * verifier won't be able to validate BPF program
+			 * correctness anyways.
+			 */
+			pr_warn("prog '%s': no BTF-based attach target is specified, use bpf_program__set_attach_target()\n",
+				prog->name);
+			return -EINVAL;
+		}
+		attach_name++; /* skip over / */
+
+		err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, &btf_type_id);
+		if (err)
+			return err;
+
+		/* cache resolved BTF FD and BTF type ID in the prog */
+		prog->attach_btf_obj_fd = btf_obj_fd;
+		prog->attach_btf_id = btf_type_id;
+
+		/* but by now libbpf common logic is not utilizing
+		 * prog->attach_btf_obj_fd/prog->attach_btf_id anymore because
+		 * this callback is called after opts were populated by
+		 * libbpf, so this callback has to update opts explicitly here
+		 */
+		opts->attach_btf_obj_fd = btf_obj_fd;
+		opts->attach_btf_id = btf_type_id;
+	}
+
+	if (is_tracing_multi(prog->expected_attach_type)) {
+		int err, btf_obj_fd = 0;
+
+		err = tracing_multi_mod_fd(prog, &btf_obj_fd);
+		if (err < 0)
+			return err;
+
+		prog->attach_btf_obj_fd = btf_obj_fd;
+		opts->attach_btf_obj_fd = btf_obj_fd;
+	}
+
+	return 0;
+}
+
+static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz);
+
+static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog,
+				struct bpf_insn *insns, int insns_cnt,
+				const char *license, __u32 kern_version, int *prog_fd)
+{
+	LIBBPF_OPTS(bpf_prog_load_opts, load_attr);
+	const char *prog_name = NULL;
+	size_t log_buf_size = 0;
+	char *log_buf = NULL, *tmp;
+	bool own_log_buf = true;
+	__u32 log_level = prog->log_level;
+	int ret, err;
+
+	/* Be more helpful by rejecting programs that can't be validated early
+	 * with more meaningful and actionable error message.
+	 */
+	switch (prog->type) {
+	case BPF_PROG_TYPE_UNSPEC:
+		/*
+		 * The program type must be set.  Most likely we couldn't find a proper
+		 * section definition at load time, and thus we didn't infer the type.
+		 */
+		pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n",
+			prog->name, prog->sec_name);
+		return -EINVAL;
+	case BPF_PROG_TYPE_STRUCT_OPS:
+		if (prog->attach_btf_id == 0) {
+			pr_warn("prog '%s': SEC(\"struct_ops\") program isn't referenced anywhere, did you forget to use it?\n",
+				prog->name);
+			return -EINVAL;
+		}
+		break;
+	default:
+		break;
+	}
+
+	if (!insns || !insns_cnt)
+		return -EINVAL;
+
+	if (kernel_supports(obj, FEAT_PROG_NAME))
+		prog_name = prog->name;
+	load_attr.attach_prog_fd = prog->attach_prog_fd;
+	load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd;
+	load_attr.attach_btf_id = prog->attach_btf_id;
+	load_attr.kern_version = kern_version;
+	load_attr.prog_ifindex = prog->prog_ifindex;
+	load_attr.expected_attach_type = prog->expected_attach_type;
+
+	/* specify func_info/line_info only if kernel supports them */
+	if (obj->btf && btf__fd(obj->btf) >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) {
+		load_attr.prog_btf_fd = btf__fd(obj->btf);
+		load_attr.func_info = prog->func_info;
+		load_attr.func_info_rec_size = prog->func_info_rec_size;
+		load_attr.func_info_cnt = prog->func_info_cnt;
+		load_attr.line_info = prog->line_info;
+		load_attr.line_info_rec_size = prog->line_info_rec_size;
+		load_attr.line_info_cnt = prog->line_info_cnt;
+	}
+	load_attr.log_level = log_level;
+	load_attr.prog_flags = prog->prog_flags;
+	load_attr.fd_array = obj->fd_array;
+
+	load_attr.token_fd = obj->token_fd;
+	if (obj->token_fd)
+		load_attr.prog_flags |= BPF_F_TOKEN_FD;
+
+	/* adjust load_attr if sec_def provides custom preload callback */
+	if (prog->sec_def && prog->sec_def->prog_prepare_load_fn) {
+		err = prog->sec_def->prog_prepare_load_fn(prog, &load_attr, prog->sec_def->cookie);
+		if (err < 0) {
+			pr_warn("prog '%s': failed to prepare load attributes: %s\n",
+				prog->name, errstr(err));
+			return err;
+		}
+		insns = prog->insns;
+		insns_cnt = prog->insns_cnt;
+	}
+
+	if (obj->gen_loader) {
+		bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name,
+				   license, insns, insns_cnt, &load_attr,
+				   prog - obj->programs);
+		*prog_fd = -1;
+		return 0;
+	}
+
+retry_load:
+	/* if log_level is zero, we don't request logs initially even if
+	 * custom log_buf is specified; if the program load fails, then we'll
+	 * bump log_level to 1 and use either custom log_buf or we'll allocate
+	 * our own and retry the load to get details on what failed
+	 */
+	if (log_level) {
+		if (prog->log_buf) {
+			log_buf = prog->log_buf;
+			log_buf_size = prog->log_size;
+			own_log_buf = false;
+		} else if (obj->log_buf) {
+			log_buf = obj->log_buf;
+			log_buf_size = obj->log_size;
+			own_log_buf = false;
+		} else {
+			log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, log_buf_size * 2);
+			tmp = realloc(log_buf, log_buf_size);
+			if (!tmp) {
+				ret = -ENOMEM;
+				goto out;
+			}
+			log_buf = tmp;
+			log_buf[0] = '\0';
+			own_log_buf = true;
+		}
+	}
+
+	load_attr.log_buf = log_buf;
+	load_attr.log_size = log_buf_size;
+	load_attr.log_level = log_level;
+
+	ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr);
+	if (ret >= 0) {
+		if (log_level && own_log_buf) {
+			pr_debug("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n",
+				 prog->name, log_buf);
+		}
+
+		if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) {
+			struct bpf_map *map;
+			int i;
+
+			for (i = 0; i < obj->nr_maps; i++) {
+				map = &prog->obj->maps[i];
+				if (map->libbpf_type != LIBBPF_MAP_RODATA)
+					continue;
+
+				if (bpf_prog_bind_map(ret, map->fd, NULL)) {
+					pr_warn("prog '%s': failed to bind map '%s': %s\n",
+						prog->name, map->real_name, errstr(errno));
+					/* Don't fail hard if can't bind rodata. */
+				}
+			}
+		}
+
+		*prog_fd = ret;
+		ret = 0;
+		goto out;
+	}
+
+	if (log_level == 0) {
+		log_level = 1;
+		goto retry_load;
+	}
+	/* On ENOSPC, increase log buffer size and retry, unless custom
+	 * log_buf is specified.
+	 * Be careful to not overflow u32, though. Kernel's log buf size limit
+	 * isn't part of UAPI so it can always be bumped to full 4GB. So don't
+	 * multiply by 2 unless we are sure we'll fit within 32 bits.
+	 * Currently, we'll get -EINVAL when we reach (UINT_MAX >> 2).
+	 */
+	if (own_log_buf && errno == ENOSPC && log_buf_size <= UINT_MAX / 2)
+		goto retry_load;
+
+	ret = -errno;
+
+	/* post-process verifier log to improve error descriptions */
+	fixup_verifier_log(prog, log_buf, log_buf_size);
+
+	pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, errstr(errno));
+	pr_perm_msg(ret);
+
+	if (own_log_buf && log_buf && log_buf[0] != '\0') {
+		pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n",
+			prog->name, log_buf);
+	}
+
+out:
+	if (own_log_buf)
+		free(log_buf);
+	return ret;
+}
+
+static char *find_prev_line(char *buf, char *cur)
+{
+	char *p;
+
+	if (cur == buf) /* end of a log buf */
+		return NULL;
+
+	p = cur - 1;
+	while (p - 1 >= buf && *(p - 1) != '\n')
+		p--;
+
+	return p;
+}
+
+static void patch_log(char *buf, size_t buf_sz, size_t log_sz,
+		      char *orig, size_t orig_sz, const char *patch)
+{
+	/* size of the remaining log content to the right from the to-be-replaced part */
+	size_t rem_sz = (buf + log_sz) - (orig + orig_sz);
+	size_t patch_sz = strlen(patch);
+
+	if (patch_sz != orig_sz) {
+		/* If patch line(s) are longer than original piece of verifier log,
+		 * shift log contents by (patch_sz - orig_sz) bytes to the right
+		 * starting from after to-be-replaced part of the log.
+		 *
+		 * If patch line(s) are shorter than original piece of verifier log,
+		 * shift log contents by (orig_sz - patch_sz) bytes to the left
+		 * starting from after to-be-replaced part of the log
+		 *
+		 * We need to be careful about not overflowing available
+		 * buf_sz capacity. If that's the case, we'll truncate the end
+		 * of the original log, as necessary.
+		 */
+		if (patch_sz > orig_sz) {
+			if (orig + patch_sz >= buf + buf_sz) {
+				/* patch is big enough to cover remaining space completely */
+				patch_sz -= (orig + patch_sz) - (buf + buf_sz) + 1;
+				rem_sz = 0;
+			} else if (patch_sz - orig_sz > buf_sz - log_sz) {
+				/* patch causes part of remaining log to be truncated */
+				rem_sz -= (patch_sz - orig_sz) - (buf_sz - log_sz);
+			}
+		}
+		/* shift remaining log to the right by calculated amount */
+		memmove(orig + patch_sz, orig + orig_sz, rem_sz);
+	}
+
+	memcpy(orig, patch, patch_sz);
+}
+
+static void fixup_log_failed_core_relo(struct bpf_program *prog,
+				       char *buf, size_t buf_sz, size_t log_sz,
+				       char *line1, char *line2, char *line3)
+{
+	/* Expected log for failed and not properly guarded CO-RE relocation:
+	 * line1 -> 123: (85) call unknown#195896080
+	 * line2 -> invalid func unknown#195896080
+	 * line3 -> <anything else or end of buffer>
+	 *
+	 * "123" is the index of the instruction that was poisoned. We extract
+	 * instruction index to find corresponding CO-RE relocation and
+	 * replace this part of the log with more relevant information about
+	 * failed CO-RE relocation.
+	 */
+	const struct bpf_core_relo *relo;
+	struct bpf_core_spec spec;
+	char patch[512], spec_buf[256];
+	int insn_idx, err, spec_len;
+
+	if (sscanf(line1, "%d: (%*d) call unknown#195896080\n", &insn_idx) != 1)
+		return;
+
+	relo = find_relo_core(prog, insn_idx);
+	if (!relo)
+		return;
+
+	err = bpf_core_parse_spec(prog->name, prog->obj->btf, relo, &spec);
+	if (err)
+		return;
+
+	spec_len = bpf_core_format_spec(spec_buf, sizeof(spec_buf), &spec);
+	snprintf(patch, sizeof(patch),
+		 "%d: <invalid CO-RE relocation>\n"
+		 "failed to resolve CO-RE relocation %s%s\n",
+		 insn_idx, spec_buf, spec_len >= sizeof(spec_buf) ? "..." : "");
+
+	patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch);
+}
+
+static void fixup_log_missing_map_load(struct bpf_program *prog,
+				       char *buf, size_t buf_sz, size_t log_sz,
+				       char *line1, char *line2, char *line3)
+{
+	/* Expected log for failed and not properly guarded map reference:
+	 * line1 -> 123: (85) call unknown#2001000345
+	 * line2 -> invalid func unknown#2001000345
+	 * line3 -> <anything else or end of buffer>
+	 *
+	 * "123" is the index of the instruction that was poisoned.
+	 * "345" in "2001000345" is a map index in obj->maps to fetch map name.
+	 */
+	struct bpf_object *obj = prog->obj;
+	const struct bpf_map *map;
+	int insn_idx, map_idx;
+	char patch[128];
+
+	if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &map_idx) != 2)
+		return;
+
+	map_idx -= POISON_LDIMM64_MAP_BASE;
+	if (map_idx < 0 || map_idx >= obj->nr_maps)
+		return;
+	map = &obj->maps[map_idx];
+
+	snprintf(patch, sizeof(patch),
+		 "%d: <invalid BPF map reference>\n"
+		 "BPF map '%s' is referenced but wasn't created\n",
+		 insn_idx, map->name);
+
+	patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch);
+}
+
+static void fixup_log_missing_kfunc_call(struct bpf_program *prog,
+					 char *buf, size_t buf_sz, size_t log_sz,
+					 char *line1, char *line2, char *line3)
+{
+	/* Expected log for failed and not properly guarded kfunc call:
+	 * line1 -> 123: (85) call unknown#2002000345
+	 * line2 -> invalid func unknown#2002000345
+	 * line3 -> <anything else or end of buffer>
+	 *
+	 * "123" is the index of the instruction that was poisoned.
+	 * "345" in "2002000345" is an extern index in obj->externs to fetch kfunc name.
+	 */
+	struct bpf_object *obj = prog->obj;
+	const struct extern_desc *ext;
+	int insn_idx, ext_idx;
+	char patch[128];
+
+	if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &ext_idx) != 2)
+		return;
+
+	ext_idx -= POISON_CALL_KFUNC_BASE;
+	if (ext_idx < 0 || ext_idx >= obj->nr_extern)
+		return;
+	ext = &obj->externs[ext_idx];
+
+	snprintf(patch, sizeof(patch),
+		 "%d: <invalid kfunc call>\n"
+		 "kfunc '%s' is referenced but wasn't resolved\n",
+		 insn_idx, ext->name);
+
+	patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch);
+}
+
+static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz)
+{
+	/* look for familiar error patterns in last N lines of the log */
+	const size_t max_last_line_cnt = 10;
+	char *prev_line, *cur_line, *next_line;
+	size_t log_sz;
+	int i;
+
+	if (!buf)
+		return;
+
+	log_sz = strlen(buf) + 1;
+	next_line = buf + log_sz - 1;
+
+	for (i = 0; i < max_last_line_cnt; i++, next_line = cur_line) {
+		cur_line = find_prev_line(buf, next_line);
+		if (!cur_line)
+			return;
+
+		if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) {
+			prev_line = find_prev_line(buf, cur_line);
+			if (!prev_line)
+				continue;
+
+			/* failed CO-RE relocation case */
+			fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz,
+						   prev_line, cur_line, next_line);
+			return;
+		} else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_LDIMM64_MAP_PFX)) {
+			prev_line = find_prev_line(buf, cur_line);
+			if (!prev_line)
+				continue;
+
+			/* reference to uncreated BPF map */
+			fixup_log_missing_map_load(prog, buf, buf_sz, log_sz,
+						   prev_line, cur_line, next_line);
+			return;
+		} else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_CALL_KFUNC_PFX)) {
+			prev_line = find_prev_line(buf, cur_line);
+			if (!prev_line)
+				continue;
+
+			/* reference to unresolved kfunc */
+			fixup_log_missing_kfunc_call(prog, buf, buf_sz, log_sz,
+						     prev_line, cur_line, next_line);
+			return;
+		}
+	}
+}
+
+static int bpf_program_record_relos(struct bpf_program *prog)
+{
+	struct bpf_object *obj = prog->obj;
+	int i;
+
+	for (i = 0; i < prog->nr_reloc; i++) {
+		struct reloc_desc *relo = &prog->reloc_desc[i];
+		struct extern_desc *ext = &obj->externs[relo->ext_idx];
+		int kind;
+
+		switch (relo->type) {
+		case RELO_EXTERN_LD64:
+			if (ext->type != EXT_KSYM)
+				continue;
+			kind = btf_is_var(btf__type_by_id(obj->btf, ext->btf_id)) ?
+				BTF_KIND_VAR : BTF_KIND_FUNC;
+			bpf_gen__record_extern(obj->gen_loader, ext->name,
+					       ext->is_weak, !ext->ksym.type_id,
+					       true, kind, relo->insn_idx);
+			break;
+		case RELO_EXTERN_CALL:
+			bpf_gen__record_extern(obj->gen_loader, ext->name,
+					       ext->is_weak, false, false, BTF_KIND_FUNC,
+					       relo->insn_idx);
+			break;
+		case RELO_CORE: {
+			struct bpf_core_relo cr = {
+				.insn_off = relo->insn_idx * 8,
+				.type_id = relo->core_relo->type_id,
+				.access_str_off = relo->core_relo->access_str_off,
+				.kind = relo->core_relo->kind,
+			};
+
+			bpf_gen__record_relo_core(obj->gen_loader, &cr);
+			break;
+		}
+		default:
+			continue;
+		}
+	}
+	return 0;
+}
+
+static int
+bpf_object__load_progs(struct bpf_object *obj, int log_level)
+{
+	struct bpf_program *prog;
+	size_t i;
+	int err;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		if (prog_is_subprog(obj, prog))
+			continue;
+		if (!prog->autoload) {
+			pr_debug("prog '%s': skipped loading\n", prog->name);
+			continue;
+		}
+		prog->log_level |= log_level;
+
+		if (obj->gen_loader)
+			bpf_program_record_relos(prog);
+
+		err = bpf_object_load_prog(obj, prog, prog->insns, prog->insns_cnt,
+					   obj->license, obj->kern_version, &prog->fd);
+		if (err) {
+			pr_warn("prog '%s': failed to load: %s\n", prog->name, errstr(err));
+			return err;
+		}
+	}
+
+	bpf_object__free_relocs(obj);
+	return 0;
+}
+
+static int bpf_object_prepare_progs(struct bpf_object *obj)
+{
+	struct bpf_program *prog;
+	size_t i;
+	int err;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		err = bpf_object__sanitize_prog(obj, prog);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static const struct bpf_sec_def *find_sec_def(const char *sec_name);
+
+static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object_open_opts *opts)
+{
+	struct bpf_program *prog;
+	int err;
+
+	bpf_object__for_each_program(prog, obj) {
+		prog->sec_def = find_sec_def(prog->sec_name);
+		if (!prog->sec_def) {
+			/* couldn't guess, but user might manually specify */
+			pr_debug("prog '%s': unrecognized ELF section name '%s'\n",
+				prog->name, prog->sec_name);
+			continue;
+		}
+
+		prog->type = prog->sec_def->prog_type;
+		prog->expected_attach_type = prog->sec_def->expected_attach_type;
+
+		/* sec_def can have custom callback which should be called
+		 * after bpf_program is initialized to adjust its properties
+		 */
+		if (prog->sec_def->prog_setup_fn) {
+			err = prog->sec_def->prog_setup_fn(prog, prog->sec_def->cookie);
+			if (err < 0) {
+				pr_warn("prog '%s': failed to initialize: %s\n",
+					prog->name, errstr(err));
+				return err;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf, size_t obj_buf_sz,
+					  const char *obj_name,
+					  const struct bpf_object_open_opts *opts)
+{
+	const char *kconfig, *btf_tmp_path, *token_path;
+	struct bpf_object *obj;
+	int err;
+	char *log_buf;
+	size_t log_size;
+	__u32 log_level;
+
+	if (obj_buf && !obj_name)
+		return ERR_PTR(-EINVAL);
+
+	if (elf_version(EV_CURRENT) == EV_NONE) {
+		pr_warn("failed to init libelf for %s\n",
+			path ? : "(mem buf)");
+		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
+	}
+
+	if (!OPTS_VALID(opts, bpf_object_open_opts))
+		return ERR_PTR(-EINVAL);
+
+	obj_name = OPTS_GET(opts, object_name, NULL) ?: obj_name;
+	if (obj_buf) {
+		path = obj_name;
+		pr_debug("loading object '%s' from buffer\n", obj_name);
+	} else {
+		pr_debug("loading object from %s\n", path);
+	}
+
+	log_buf = OPTS_GET(opts, kernel_log_buf, NULL);
+	log_size = OPTS_GET(opts, kernel_log_size, 0);
+	log_level = OPTS_GET(opts, kernel_log_level, 0);
+	if (log_size > UINT_MAX)
+		return ERR_PTR(-EINVAL);
+	if (log_size && !log_buf)
+		return ERR_PTR(-EINVAL);
+
+	token_path = OPTS_GET(opts, bpf_token_path, NULL);
+	/* if user didn't specify bpf_token_path explicitly, check if
+	 * LIBBPF_BPF_TOKEN_PATH envvar was set and treat it as bpf_token_path
+	 * option
+	 */
+	if (!token_path)
+		token_path = getenv("LIBBPF_BPF_TOKEN_PATH");
+	if (token_path && strlen(token_path) >= PATH_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
+	if (IS_ERR(obj))
+		return obj;
+
+	obj->log_buf = log_buf;
+	obj->log_size = log_size;
+	obj->log_level = log_level;
+
+	if (token_path) {
+		obj->token_path = strdup(token_path);
+		if (!obj->token_path) {
+			err = -ENOMEM;
+			goto out;
+		}
+	}
+
+	btf_tmp_path = OPTS_GET(opts, btf_custom_path, NULL);
+	if (btf_tmp_path) {
+		if (strlen(btf_tmp_path) >= PATH_MAX) {
+			err = -ENAMETOOLONG;
+			goto out;
+		}
+		obj->btf_custom_path = strdup(btf_tmp_path);
+		if (!obj->btf_custom_path) {
+			err = -ENOMEM;
+			goto out;
+		}
+	}
+
+	kconfig = OPTS_GET(opts, kconfig, NULL);
+	if (kconfig) {
+		obj->kconfig = strdup(kconfig);
+		if (!obj->kconfig) {
+			err = -ENOMEM;
+			goto out;
+		}
+	}
+
+	err = bpf_object__elf_init(obj);
+	err = err ? : bpf_object__elf_collect(obj);
+	err = err ? : bpf_object__collect_externs(obj);
+	err = err ? : bpf_object_fixup_btf(obj);
+	err = err ? : bpf_object__init_maps(obj, opts);
+	err = err ? : bpf_object_init_progs(obj, opts);
+	err = err ? : bpf_object__collect_relos(obj);
+	if (err)
+		goto out;
+
+	bpf_object__elf_finish(obj);
+
+	return obj;
+out:
+	bpf_object__close(obj);
+	return ERR_PTR(err);
+}
+
+struct bpf_object *
+bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)
+{
+	if (!path)
+		return libbpf_err_ptr(-EINVAL);
+
+	return libbpf_ptr(bpf_object_open(path, NULL, 0, NULL, opts));
+}
+
+struct bpf_object *bpf_object__open(const char *path)
+{
+	return bpf_object__open_file(path, NULL);
+}
+
+struct bpf_object *
+bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
+		     const struct bpf_object_open_opts *opts)
+{
+	char tmp_name[64];
+
+	if (!obj_buf || obj_buf_sz == 0)
+		return libbpf_err_ptr(-EINVAL);
+
+	/* create a (quite useless) default "name" for this memory buffer object */
+	snprintf(tmp_name, sizeof(tmp_name), "%lx-%zx", (unsigned long)obj_buf, obj_buf_sz);
+
+	return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, tmp_name, opts));
+}
+
+static int bpf_object_unload(struct bpf_object *obj)
+{
+	size_t i;
+
+	if (!obj)
+		return libbpf_err(-EINVAL);
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		zclose(obj->maps[i].fd);
+		if (obj->maps[i].st_ops)
+			zfree(&obj->maps[i].st_ops->kern_vdata);
+	}
+
+	for (i = 0; i < obj->nr_programs; i++)
+		bpf_program__unload(&obj->programs[i]);
+
+	return 0;
+}
+
+static int bpf_object__sanitize_maps(struct bpf_object *obj)
+{
+	struct bpf_map *m;
+
+	bpf_object__for_each_map(m, obj) {
+		if (!bpf_map__is_internal(m))
+			continue;
+		if (!kernel_supports(obj, FEAT_ARRAY_MMAP))
+			m->def.map_flags &= ~BPF_F_MMAPABLE;
+	}
+
+	return 0;
+}
+
+typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type,
+			     const char *sym_name, void *ctx);
+
+static int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx)
+{
+	char sym_type, sym_name[500];
+	unsigned long long sym_addr;
+	int ret, err = 0;
+	FILE *f;
+
+	f = fopen("/proc/kallsyms", "re");
+	if (!f) {
+		err = -errno;
+		pr_warn("failed to open /proc/kallsyms: %s\n", errstr(err));
+		return err;
+	}
+
+	while (true) {
+		ret = fscanf(f, "%llx %c %499s%*[^\n]\n",
+			     &sym_addr, &sym_type, sym_name);
+		if (ret == EOF && feof(f))
+			break;
+		if (ret != 3) {
+			pr_warn("failed to read kallsyms entry: %d\n", ret);
+			err = -EINVAL;
+			break;
+		}
+
+		err = cb(sym_addr, sym_type, sym_name, ctx);
+		if (err)
+			break;
+	}
+
+	fclose(f);
+	return err;
+}
+
+static int kallsyms_cb(unsigned long long sym_addr, char sym_type,
+		       const char *sym_name, void *ctx)
+{
+	struct bpf_object *obj = ctx;
+	const struct btf_type *t;
+	struct extern_desc *ext;
+	const char *res;
+
+	res = strstr(sym_name, ".llvm.");
+	if (sym_type == 'd' && res)
+		ext = find_extern_by_name_with_len(obj, sym_name, res - sym_name);
+	else
+		ext = find_extern_by_name(obj, sym_name);
+	if (!ext || ext->type != EXT_KSYM)
+		return 0;
+
+	t = btf__type_by_id(obj->btf, ext->btf_id);
+	if (!btf_is_var(t))
+		return 0;
+
+	if (ext->is_set && ext->ksym.addr != sym_addr) {
+		pr_warn("extern (ksym) '%s': resolution is ambiguous: 0x%llx or 0x%llx\n",
+			sym_name, ext->ksym.addr, sym_addr);
+		return -EINVAL;
+	}
+	if (!ext->is_set) {
+		ext->is_set = true;
+		ext->ksym.addr = sym_addr;
+		pr_debug("extern (ksym) '%s': set to 0x%llx\n", sym_name, sym_addr);
+	}
+	return 0;
+}
+
+static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
+{
+	return libbpf_kallsyms_parse(kallsyms_cb, obj);
+}
+
+static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name,
+			    __u16 kind, struct btf **res_btf,
+			    struct module_btf **res_mod_btf)
+{
+	struct module_btf *mod_btf;
+	struct btf *btf;
+	int i, id, err;
+
+	btf = obj->btf_vmlinux;
+	mod_btf = NULL;
+	id = btf__find_by_name_kind(btf, ksym_name, kind);
+
+	if (id == -ENOENT) {
+		err = load_module_btfs(obj);
+		if (err)
+			return err;
+
+		for (i = 0; i < obj->btf_module_cnt; i++) {
+			/* we assume module_btf's BTF FD is always >0 */
+			mod_btf = &obj->btf_modules[i];
+			btf = mod_btf->btf;
+			id = btf__find_by_name_kind_own(btf, ksym_name, kind);
+			if (id != -ENOENT)
+				break;
+		}
+	}
+	if (id <= 0)
+		return -ESRCH;
+
+	*res_btf = btf;
+	*res_mod_btf = mod_btf;
+	return id;
+}
+
+static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
+					       struct extern_desc *ext)
+{
+	const struct btf_type *targ_var, *targ_type;
+	__u32 targ_type_id, local_type_id;
+	struct module_btf *mod_btf = NULL;
+	const char *targ_var_name;
+	struct btf *btf = NULL;
+	int id, err;
+
+	id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf);
+	if (id < 0) {
+		if (id == -ESRCH && ext->is_weak)
+			return 0;
+		pr_warn("extern (var ksym) '%s': not found in kernel BTF\n",
+			ext->name);
+		return id;
+	}
+
+	/* find local type_id */
+	local_type_id = ext->ksym.type_id;
+
+	/* find target type_id */
+	targ_var = btf__type_by_id(btf, id);
+	targ_var_name = btf__name_by_offset(btf, targ_var->name_off);
+	targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
+
+	err = bpf_core_types_are_compat(obj->btf, local_type_id,
+					btf, targ_type_id);
+	if (err <= 0) {
+		const struct btf_type *local_type;
+		const char *targ_name, *local_name;
+
+		local_type = btf__type_by_id(obj->btf, local_type_id);
+		local_name = btf__name_by_offset(obj->btf, local_type->name_off);
+		targ_name = btf__name_by_offset(btf, targ_type->name_off);
+
+		pr_warn("extern (var ksym) '%s': incompatible types, expected [%u] %s %s, but kernel has [%u] %s %s\n",
+			ext->name, local_type_id,
+			btf_kind_str(local_type), local_name, targ_type_id,
+			btf_kind_str(targ_type), targ_name);
+		return -EINVAL;
+	}
+
+	ext->is_set = true;
+	ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0;
+	ext->ksym.kernel_btf_id = id;
+	pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n",
+		 ext->name, id, btf_kind_str(targ_var), targ_var_name);
+
+	return 0;
+}
+
+static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj,
+						struct extern_desc *ext)
+{
+	int local_func_proto_id, kfunc_proto_id, kfunc_id;
+	struct module_btf *mod_btf = NULL;
+	const struct btf_type *kern_func;
+	struct btf *kern_btf = NULL;
+	int ret;
+
+	local_func_proto_id = ext->ksym.type_id;
+
+	kfunc_id = find_ksym_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf,
+				    &mod_btf);
+	if (kfunc_id < 0) {
+		if (kfunc_id == -ESRCH && ext->is_weak)
+			return 0;
+		pr_warn("extern (func ksym) '%s': not found in kernel or module BTFs\n",
+			ext->name);
+		return kfunc_id;
+	}
+
+	kern_func = btf__type_by_id(kern_btf, kfunc_id);
+	kfunc_proto_id = kern_func->type;
+
+	ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id,
+					kern_btf, kfunc_proto_id);
+	if (ret <= 0) {
+		if (ext->is_weak)
+			return 0;
+
+		pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with %s [%d]\n",
+			ext->name, local_func_proto_id,
+			mod_btf ? mod_btf->name : "vmlinux", kfunc_proto_id);
+		return -EINVAL;
+	}
+
+	/* set index for module BTF fd in fd_array, if unset */
+	if (mod_btf && !mod_btf->fd_array_idx) {
+		/* insn->off is s16 */
+		if (obj->fd_array_cnt == INT16_MAX) {
+			pr_warn("extern (func ksym) '%s': module BTF fd index %d too big to fit in bpf_insn offset\n",
+				ext->name, mod_btf->fd_array_idx);
+			return -E2BIG;
+		}
+		/* Cannot use index 0 for module BTF fd */
+		if (!obj->fd_array_cnt)
+			obj->fd_array_cnt = 1;
+
+		ret = libbpf_ensure_mem((void **)&obj->fd_array, &obj->fd_array_cap, sizeof(int),
+					obj->fd_array_cnt + 1);
+		if (ret)
+			return ret;
+		mod_btf->fd_array_idx = obj->fd_array_cnt;
+		/* we assume module BTF FD is always >0 */
+		obj->fd_array[obj->fd_array_cnt++] = mod_btf->fd;
+	}
+
+	ext->is_set = true;
+	ext->ksym.kernel_btf_id = kfunc_id;
+	ext->ksym.btf_fd_idx = mod_btf ? mod_btf->fd_array_idx : 0;
+	/* Also set kernel_btf_obj_fd to make sure that bpf_object__relocate_data()
+	 * populates FD into ld_imm64 insn when it's used to point to kfunc.
+	 * {kernel_btf_id, btf_fd_idx} -> fixup bpf_call.
+	 * {kernel_btf_id, kernel_btf_obj_fd} -> fixup ld_imm64.
+	 */
+	ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0;
+	pr_debug("extern (func ksym) '%s': resolved to %s [%d]\n",
+		 ext->name, mod_btf ? mod_btf->name : "vmlinux", kfunc_id);
+
+	return 0;
+}
+
+static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
+{
+	const struct btf_type *t;
+	struct extern_desc *ext;
+	int i, err;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext = &obj->externs[i];
+		if (ext->type != EXT_KSYM || !ext->ksym.type_id)
+			continue;
+
+		if (obj->gen_loader) {
+			ext->is_set = true;
+			ext->ksym.kernel_btf_obj_fd = 0;
+			ext->ksym.kernel_btf_id = 0;
+			continue;
+		}
+		t = btf__type_by_id(obj->btf, ext->btf_id);
+		if (btf_is_var(t))
+			err = bpf_object__resolve_ksym_var_btf_id(obj, ext);
+		else
+			err = bpf_object__resolve_ksym_func_btf_id(obj, ext);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int bpf_object__resolve_externs(struct bpf_object *obj,
+				       const char *extra_kconfig)
+{
+	bool need_config = false, need_kallsyms = false;
+	bool need_vmlinux_btf = false;
+	struct extern_desc *ext;
+	void *kcfg_data = NULL;
+	int err, i;
+
+	if (obj->nr_extern == 0)
+		return 0;
+
+	if (obj->kconfig_map_idx >= 0)
+		kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped;
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext = &obj->externs[i];
+
+		if (ext->type == EXT_KSYM) {
+			if (ext->ksym.type_id)
+				need_vmlinux_btf = true;
+			else
+				need_kallsyms = true;
+			continue;
+		} else if (ext->type == EXT_KCFG) {
+			void *ext_ptr = kcfg_data + ext->kcfg.data_off;
+			__u64 value = 0;
+
+			/* Kconfig externs need actual /proc/config.gz */
+			if (str_has_pfx(ext->name, "CONFIG_")) {
+				need_config = true;
+				continue;
+			}
+
+			/* Virtual kcfg externs are customly handled by libbpf */
+			if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
+				value = get_kernel_version();
+				if (!value) {
+					pr_warn("extern (kcfg) '%s': failed to get kernel version\n", ext->name);
+					return -EINVAL;
+				}
+			} else if (strcmp(ext->name, "LINUX_HAS_BPF_COOKIE") == 0) {
+				value = kernel_supports(obj, FEAT_BPF_COOKIE);
+			} else if (strcmp(ext->name, "LINUX_HAS_SYSCALL_WRAPPER") == 0) {
+				value = kernel_supports(obj, FEAT_SYSCALL_WRAPPER);
+			} else if (!str_has_pfx(ext->name, "LINUX_") || !ext->is_weak) {
+				/* Currently libbpf supports only CONFIG_ and LINUX_ prefixed
+				 * __kconfig externs, where LINUX_ ones are virtual and filled out
+				 * customly by libbpf (their values don't come from Kconfig).
+				 * If LINUX_xxx variable is not recognized by libbpf, but is marked
+				 * __weak, it defaults to zero value, just like for CONFIG_xxx
+				 * externs.
+				 */
+				pr_warn("extern (kcfg) '%s': unrecognized virtual extern\n", ext->name);
+				return -EINVAL;
+			}
+
+			err = set_kcfg_value_num(ext, ext_ptr, value);
+			if (err)
+				return err;
+			pr_debug("extern (kcfg) '%s': set to 0x%llx\n",
+				 ext->name, (unsigned long long)value);
+		} else {
+			pr_warn("extern '%s': unrecognized extern kind\n", ext->name);
+			return -EINVAL;
+		}
+	}
+	if (need_config && extra_kconfig) {
+		err = bpf_object__read_kconfig_mem(obj, extra_kconfig, kcfg_data);
+		if (err)
+			return -EINVAL;
+		need_config = false;
+		for (i = 0; i < obj->nr_extern; i++) {
+			ext = &obj->externs[i];
+			if (ext->type == EXT_KCFG && !ext->is_set) {
+				need_config = true;
+				break;
+			}
+		}
+	}
+	if (need_config) {
+		err = bpf_object__read_kconfig_file(obj, kcfg_data);
+		if (err)
+			return -EINVAL;
+	}
+	if (need_kallsyms) {
+		err = bpf_object__read_kallsyms_file(obj);
+		if (err)
+			return -EINVAL;
+	}
+	if (need_vmlinux_btf) {
+		err = bpf_object__resolve_ksyms_btf_id(obj);
+		if (err)
+			return -EINVAL;
+	}
+	for (i = 0; i < obj->nr_extern; i++) {
+		ext = &obj->externs[i];
+
+		if (!ext->is_set && !ext->is_weak) {
+			pr_warn("extern '%s' (strong): not resolved\n", ext->name);
+			return -ESRCH;
+		} else if (!ext->is_set) {
+			pr_debug("extern '%s' (weak): not resolved, defaulting to zero\n",
+				 ext->name);
+		}
+	}
+
+	return 0;
+}
+
+static void bpf_map_prepare_vdata(const struct bpf_map *map)
+{
+	const struct btf_type *type;
+	struct bpf_struct_ops *st_ops;
+	__u32 i;
+
+	st_ops = map->st_ops;
+	type = btf__type_by_id(map->obj->btf, st_ops->type_id);
+	for (i = 0; i < btf_vlen(type); i++) {
+		struct bpf_program *prog = st_ops->progs[i];
+		void *kern_data;
+		int prog_fd;
+
+		if (!prog)
+			continue;
+
+		prog_fd = bpf_program__fd(prog);
+		kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i];
+		*(unsigned long *)kern_data = prog_fd;
+	}
+}
+
+static int bpf_object_prepare_struct_ops(struct bpf_object *obj)
+{
+	struct bpf_map *map;
+	int i;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		map = &obj->maps[i];
+
+		if (!bpf_map__is_struct_ops(map))
+			continue;
+
+		if (!map->autocreate)
+			continue;
+
+		bpf_map_prepare_vdata(map);
+	}
+
+	return 0;
+}
+
+static void bpf_object_unpin(struct bpf_object *obj)
+{
+	int i;
+
+	/* unpin any maps that were auto-pinned during load */
+	for (i = 0; i < obj->nr_maps; i++)
+		if (obj->maps[i].pinned && !obj->maps[i].reused)
+			bpf_map__unpin(&obj->maps[i], NULL);
+}
+
+static void bpf_object_cleanup_btf(struct bpf_object *obj)
+{
+	int i;
+
+	/* clean up module BTFs */
+	for (i = 0; i < obj->btf_module_cnt; i++) {
+		close(obj->btf_modules[i].fd);
+		btf__free(obj->btf_modules[i].btf);
+		free(obj->btf_modules[i].name);
+	}
+	obj->btf_module_cnt = 0;
+	obj->btf_module_cap = 0;
+	obj->btf_modules_loaded = false;
+	zfree(&obj->btf_modules);
+
+	/* clean up vmlinux BTF */
+	btf__free(obj->btf_vmlinux);
+	obj->btf_vmlinux = NULL;
+}
+
+static void bpf_object_post_load_cleanup(struct bpf_object *obj)
+{
+	/* clean up fd_array */
+	zfree(&obj->fd_array);
+
+	/* clean up BTF */
+	bpf_object_cleanup_btf(obj);
+}
+
+static int bpf_object_prepare(struct bpf_object *obj, const char *target_btf_path)
+{
+	int err;
+
+	if (obj->state >= OBJ_PREPARED) {
+		pr_warn("object '%s': prepare loading can't be attempted twice\n", obj->name);
+		return -EINVAL;
+	}
+
+	err = bpf_object_prepare_token(obj);
+	err = err ? : bpf_object__probe_loading(obj);
+	err = err ? : bpf_object__load_vmlinux_btf(obj, false);
+	err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
+	err = err ? : bpf_object__sanitize_maps(obj);
+	err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
+	err = err ? : bpf_object_adjust_struct_ops_autoload(obj);
+	err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : target_btf_path);
+	err = err ? : bpf_object__sanitize_and_load_btf(obj);
+	err = err ? : bpf_object__create_maps(obj);
+	err = err ? : bpf_object_prepare_progs(obj);
+
+	if (err) {
+		bpf_object_unpin(obj);
+		bpf_object_unload(obj);
+		obj->state = OBJ_LOADED;
+		return err;
+	}
+
+	obj->state = OBJ_PREPARED;
+	return 0;
+}
+
+static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const char *target_btf_path)
+{
+	int err;
+
+	if (!obj)
+		return libbpf_err(-EINVAL);
+
+	if (obj->state >= OBJ_LOADED) {
+		pr_warn("object '%s': load can't be attempted twice\n", obj->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	/* Disallow kernel loading programs of non-native endianness but
+	 * permit cross-endian creation of "light skeleton".
+	 */
+	if (obj->gen_loader) {
+		bpf_gen__init(obj->gen_loader, extra_log_level, obj->nr_programs, obj->nr_maps);
+	} else if (!is_native_endianness(obj)) {
+		pr_warn("object '%s': loading non-native endianness is unsupported\n", obj->name);
+		return libbpf_err(-LIBBPF_ERRNO__ENDIAN);
+	}
+
+	if (obj->state < OBJ_PREPARED) {
+		err = bpf_object_prepare(obj, target_btf_path);
+		if (err)
+			return libbpf_err(err);
+	}
+	err = bpf_object__load_progs(obj, extra_log_level);
+	err = err ? : bpf_object_init_prog_arrays(obj);
+	err = err ? : bpf_object_prepare_struct_ops(obj);
+
+	if (obj->gen_loader) {
+		/* reset FDs */
+		if (obj->btf)
+			btf__set_fd(obj->btf, -1);
+		if (!err)
+			err = bpf_gen__finish(obj->gen_loader, obj->nr_programs, obj->nr_maps);
+	}
+
+	bpf_object_post_load_cleanup(obj);
+	obj->state = OBJ_LOADED; /* doesn't matter if successfully or not */
+
+	if (err) {
+		bpf_object_unpin(obj);
+		bpf_object_unload(obj);
+		pr_warn("failed to load object '%s'\n", obj->path);
+		return libbpf_err(err);
+	}
+
+	return 0;
+}
+
+int bpf_object__prepare(struct bpf_object *obj)
+{
+	return libbpf_err(bpf_object_prepare(obj, NULL));
+}
+
+int bpf_object__load(struct bpf_object *obj)
+{
+	return bpf_object_load(obj, 0, NULL);
+}
+
+static int make_parent_dir(const char *path)
+{
+	char *dname, *dir;
+	int err = 0;
+
+	dname = strdup(path);
+	if (dname == NULL)
+		return -ENOMEM;
+
+	dir = dirname(dname);
+	if (mkdir(dir, 0700) && errno != EEXIST)
+		err = -errno;
+
+	free(dname);
+	if (err) {
+		pr_warn("failed to mkdir %s: %s\n", path, errstr(err));
+	}
+	return err;
+}
+
+static int check_path(const char *path)
+{
+	struct statfs st_fs;
+	char *dname, *dir;
+	int err = 0;
+
+	if (path == NULL)
+		return -EINVAL;
+
+	dname = strdup(path);
+	if (dname == NULL)
+		return -ENOMEM;
+
+	dir = dirname(dname);
+	if (statfs(dir, &st_fs)) {
+		pr_warn("failed to statfs %s: %s\n", dir, errstr(errno));
+		err = -errno;
+	}
+	free(dname);
+
+	if (!err && st_fs.f_type != BPF_FS_MAGIC) {
+		pr_warn("specified path %s is not on BPF FS\n", path);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+int bpf_program__pin(struct bpf_program *prog, const char *path)
+{
+	int err;
+
+	if (prog->fd < 0) {
+		pr_warn("prog '%s': can't pin program that wasn't loaded\n", prog->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	err = make_parent_dir(path);
+	if (err)
+		return libbpf_err(err);
+
+	err = check_path(path);
+	if (err)
+		return libbpf_err(err);
+
+	if (bpf_obj_pin(prog->fd, path)) {
+		err = -errno;
+		pr_warn("prog '%s': failed to pin at '%s': %s\n", prog->name, path, errstr(err));
+		return libbpf_err(err);
+	}
+
+	pr_debug("prog '%s': pinned at '%s'\n", prog->name, path);
+	return 0;
+}
+
+int bpf_program__unpin(struct bpf_program *prog, const char *path)
+{
+	int err;
+
+	if (prog->fd < 0) {
+		pr_warn("prog '%s': can't unpin program that wasn't loaded\n", prog->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	err = check_path(path);
+	if (err)
+		return libbpf_err(err);
+
+	err = unlink(path);
+	if (err)
+		return libbpf_err(-errno);
+
+	pr_debug("prog '%s': unpinned from '%s'\n", prog->name, path);
+	return 0;
+}
+
+int bpf_map__pin(struct bpf_map *map, const char *path)
+{
+	int err;
+
+	if (map == NULL) {
+		pr_warn("invalid map pointer\n");
+		return libbpf_err(-EINVAL);
+	}
+
+	if (map->fd < 0) {
+		pr_warn("map '%s': can't pin BPF map without FD (was it created?)\n", map->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	if (map->pin_path) {
+		if (path && strcmp(path, map->pin_path)) {
+			pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
+				bpf_map__name(map), map->pin_path, path);
+			return libbpf_err(-EINVAL);
+		} else if (map->pinned) {
+			pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
+				 bpf_map__name(map), map->pin_path);
+			return 0;
+		}
+	} else {
+		if (!path) {
+			pr_warn("missing a path to pin map '%s' at\n",
+				bpf_map__name(map));
+			return libbpf_err(-EINVAL);
+		} else if (map->pinned) {
+			pr_warn("map '%s' already pinned\n", bpf_map__name(map));
+			return libbpf_err(-EEXIST);
+		}
+
+		map->pin_path = strdup(path);
+		if (!map->pin_path) {
+			err = -errno;
+			goto out_err;
+		}
+	}
+
+	err = make_parent_dir(map->pin_path);
+	if (err)
+		return libbpf_err(err);
+
+	err = check_path(map->pin_path);
+	if (err)
+		return libbpf_err(err);
+
+	if (bpf_obj_pin(map->fd, map->pin_path)) {
+		err = -errno;
+		goto out_err;
+	}
+
+	map->pinned = true;
+	pr_debug("pinned map '%s'\n", map->pin_path);
+
+	return 0;
+
+out_err:
+	pr_warn("failed to pin map: %s\n", errstr(err));
+	return libbpf_err(err);
+}
+
+int bpf_map__unpin(struct bpf_map *map, const char *path)
+{
+	int err;
+
+	if (map == NULL) {
+		pr_warn("invalid map pointer\n");
+		return libbpf_err(-EINVAL);
+	}
+
+	if (map->pin_path) {
+		if (path && strcmp(path, map->pin_path)) {
+			pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
+				bpf_map__name(map), map->pin_path, path);
+			return libbpf_err(-EINVAL);
+		}
+		path = map->pin_path;
+	} else if (!path) {
+		pr_warn("no path to unpin map '%s' from\n",
+			bpf_map__name(map));
+		return libbpf_err(-EINVAL);
+	}
+
+	err = check_path(path);
+	if (err)
+		return libbpf_err(err);
+
+	err = unlink(path);
+	if (err != 0)
+		return libbpf_err(-errno);
+
+	map->pinned = false;
+	pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
+
+	return 0;
+}
+
+int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
+{
+	char *new = NULL;
+
+	if (path) {
+		new = strdup(path);
+		if (!new)
+			return libbpf_err(-errno);
+	}
+
+	free(map->pin_path);
+	map->pin_path = new;
+	return 0;
+}
+
+__alias(bpf_map__pin_path)
+const char *bpf_map__get_pin_path(const struct bpf_map *map);
+
+const char *bpf_map__pin_path(const struct bpf_map *map)
+{
+	return map->pin_path;
+}
+
+bool bpf_map__is_pinned(const struct bpf_map *map)
+{
+	return map->pinned;
+}
+
+static void sanitize_pin_path(char *s)
+{
+	/* bpffs disallows periods in path names */
+	while (*s) {
+		if (*s == '.')
+			*s = '_';
+		s++;
+	}
+}
+
+int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
+{
+	struct bpf_map *map;
+	int err;
+
+	if (!obj)
+		return libbpf_err(-ENOENT);
+
+	if (obj->state < OBJ_PREPARED) {
+		pr_warn("object not yet loaded; load it first\n");
+		return libbpf_err(-ENOENT);
+	}
+
+	bpf_object__for_each_map(map, obj) {
+		char *pin_path = NULL;
+		char buf[PATH_MAX];
+
+		if (!map->autocreate)
+			continue;
+
+		if (path) {
+			err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map));
+			if (err)
+				goto err_unpin_maps;
+			sanitize_pin_path(buf);
+			pin_path = buf;
+		} else if (!map->pin_path) {
+			continue;
+		}
+
+		err = bpf_map__pin(map, pin_path);
+		if (err)
+			goto err_unpin_maps;
+	}
+
+	return 0;
+
+err_unpin_maps:
+	while ((map = bpf_object__prev_map(obj, map))) {
+		if (!map->pin_path)
+			continue;
+
+		bpf_map__unpin(map, NULL);
+	}
+
+	return libbpf_err(err);
+}
+
+int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
+{
+	struct bpf_map *map;
+	int err;
+
+	if (!obj)
+		return libbpf_err(-ENOENT);
+
+	bpf_object__for_each_map(map, obj) {
+		char *pin_path = NULL;
+		char buf[PATH_MAX];
+
+		if (path) {
+			err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map));
+			if (err)
+				return libbpf_err(err);
+			sanitize_pin_path(buf);
+			pin_path = buf;
+		} else if (!map->pin_path) {
+			continue;
+		}
+
+		err = bpf_map__unpin(map, pin_path);
+		if (err)
+			return libbpf_err(err);
+	}
+
+	return 0;
+}
+
+int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
+{
+	struct bpf_program *prog;
+	char buf[PATH_MAX];
+	int err;
+
+	if (!obj)
+		return libbpf_err(-ENOENT);
+
+	if (obj->state < OBJ_LOADED) {
+		pr_warn("object not yet loaded; load it first\n");
+		return libbpf_err(-ENOENT);
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		err = pathname_concat(buf, sizeof(buf), path, prog->name);
+		if (err)
+			goto err_unpin_programs;
+
+		err = bpf_program__pin(prog, buf);
+		if (err)
+			goto err_unpin_programs;
+	}
+
+	return 0;
+
+err_unpin_programs:
+	while ((prog = bpf_object__prev_program(obj, prog))) {
+		if (pathname_concat(buf, sizeof(buf), path, prog->name))
+			continue;
+
+		bpf_program__unpin(prog, buf);
+	}
+
+	return libbpf_err(err);
+}
+
+int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
+{
+	struct bpf_program *prog;
+	int err;
+
+	if (!obj)
+		return libbpf_err(-ENOENT);
+
+	bpf_object__for_each_program(prog, obj) {
+		char buf[PATH_MAX];
+
+		err = pathname_concat(buf, sizeof(buf), path, prog->name);
+		if (err)
+			return libbpf_err(err);
+
+		err = bpf_program__unpin(prog, buf);
+		if (err)
+			return libbpf_err(err);
+	}
+
+	return 0;
+}
+
+int bpf_object__pin(struct bpf_object *obj, const char *path)
+{
+	int err;
+
+	err = bpf_object__pin_maps(obj, path);
+	if (err)
+		return libbpf_err(err);
+
+	err = bpf_object__pin_programs(obj, path);
+	if (err) {
+		bpf_object__unpin_maps(obj, path);
+		return libbpf_err(err);
+	}
+
+	return 0;
+}
+
+int bpf_object__unpin(struct bpf_object *obj, const char *path)
+{
+	int err;
+
+	err = bpf_object__unpin_programs(obj, path);
+	if (err)
+		return libbpf_err(err);
+
+	err = bpf_object__unpin_maps(obj, path);
+	if (err)
+		return libbpf_err(err);
+
+	return 0;
+}
+
+static void bpf_map__destroy(struct bpf_map *map)
+{
+	if (map->inner_map) {
+		bpf_map__destroy(map->inner_map);
+		zfree(&map->inner_map);
+	}
+
+	zfree(&map->init_slots);
+	map->init_slots_sz = 0;
+
+	if (map->mmaped && map->mmaped != map->obj->arena_data)
+		munmap(map->mmaped, bpf_map_mmap_sz(map));
+	map->mmaped = NULL;
+
+	if (map->st_ops) {
+		zfree(&map->st_ops->data);
+		zfree(&map->st_ops->progs);
+		zfree(&map->st_ops->kern_func_off);
+		zfree(&map->st_ops);
+	}
+
+	zfree(&map->name);
+	zfree(&map->real_name);
+	zfree(&map->pin_path);
+
+	if (map->fd >= 0)
+		zclose(map->fd);
+}
+
+void bpf_object__close(struct bpf_object *obj)
+{
+	size_t i;
+
+	if (IS_ERR_OR_NULL(obj))
+		return;
+
+	/*
+	 * if user called bpf_object__prepare() without ever getting to
+	 * bpf_object__load(), we need to clean up stuff that is normally
+	 * cleaned up at the end of loading step
+	 */
+	bpf_object_post_load_cleanup(obj);
+
+	usdt_manager_free(obj->usdt_man);
+	obj->usdt_man = NULL;
+
+	bpf_gen__free(obj->gen_loader);
+	bpf_object__elf_finish(obj);
+	bpf_object_unload(obj);
+	btf__free(obj->btf);
+	btf__free(obj->btf_vmlinux);
+	btf_ext__free(obj->btf_ext);
+
+	for (i = 0; i < obj->nr_maps; i++)
+		bpf_map__destroy(&obj->maps[i]);
+
+	zfree(&obj->btf_custom_path);
+	zfree(&obj->kconfig);
+
+	for (i = 0; i < obj->nr_extern; i++) {
+		zfree(&obj->externs[i].name);
+		zfree(&obj->externs[i].essent_name);
+	}
+
+	zfree(&obj->externs);
+	obj->nr_extern = 0;
+
+	zfree(&obj->maps);
+	obj->nr_maps = 0;
+
+	if (obj->programs && obj->nr_programs) {
+		for (i = 0; i < obj->nr_programs; i++)
+			bpf_program__exit(&obj->programs[i]);
+	}
+	zfree(&obj->programs);
+
+	zfree(&obj->feat_cache);
+	zfree(&obj->token_path);
+	if (obj->token_fd > 0)
+		close(obj->token_fd);
+
+	zfree(&obj->arena_data);
+
+	zfree(&obj->jumptables_data);
+	obj->jumptables_data_sz = 0;
+
+	for (i = 0; i < obj->jumptable_map_cnt; i++)
+		close(obj->jumptable_maps[i].fd);
+	zfree(&obj->jumptable_maps);
+
+	free(obj);
+}
+
+const char *bpf_object__name(const struct bpf_object *obj)
+{
+	return obj ? obj->name : libbpf_err_ptr(-EINVAL);
+}
+
+unsigned int bpf_object__kversion(const struct bpf_object *obj)
+{
+	return obj ? obj->kern_version : 0;
+}
+
+int bpf_object__token_fd(const struct bpf_object *obj)
+{
+	return obj->token_fd ?: -1;
+}
+
+struct btf *bpf_object__btf(const struct bpf_object *obj)
+{
+	return obj ? obj->btf : NULL;
+}
+
+int bpf_object__btf_fd(const struct bpf_object *obj)
+{
+	return obj->btf ? btf__fd(obj->btf) : -1;
+}
+
+int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version)
+{
+	if (obj->state >= OBJ_LOADED)
+		return libbpf_err(-EINVAL);
+
+	obj->kern_version = kern_version;
+
+	return 0;
+}
+
+int bpf_object__gen_loader(struct bpf_object *obj, struct gen_loader_opts *opts)
+{
+	struct bpf_gen *gen;
+
+	if (!opts)
+		return libbpf_err(-EFAULT);
+	if (!OPTS_VALID(opts, gen_loader_opts))
+		return libbpf_err(-EINVAL);
+	gen = calloc(1, sizeof(*gen));
+	if (!gen)
+		return libbpf_err(-ENOMEM);
+	gen->opts = opts;
+	gen->swapped_endian = !is_native_endianness(obj);
+	obj->gen_loader = gen;
+	return 0;
+}
+
+static struct bpf_program *
+__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
+		    bool forward)
+{
+	size_t nr_programs = obj->nr_programs;
+	ssize_t idx;
+
+	if (!nr_programs)
+		return NULL;
+
+	if (!p)
+		/* Iter from the beginning */
+		return forward ? &obj->programs[0] :
+			&obj->programs[nr_programs - 1];
+
+	if (p->obj != obj) {
+		pr_warn("error: program handler doesn't match object\n");
+		return errno = EINVAL, NULL;
+	}
+
+	idx = (p - obj->programs) + (forward ? 1 : -1);
+	if (idx >= obj->nr_programs || idx < 0)
+		return NULL;
+	return &obj->programs[idx];
+}
+
+struct bpf_program *
+bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev)
+{
+	struct bpf_program *prog = prev;
+
+	do {
+		prog = __bpf_program__iter(prog, obj, true);
+	} while (prog && prog_is_subprog(obj, prog));
+
+	return prog;
+}
+
+struct bpf_program *
+bpf_object__prev_program(const struct bpf_object *obj, struct bpf_program *next)
+{
+	struct bpf_program *prog = next;
+
+	do {
+		prog = __bpf_program__iter(prog, obj, false);
+	} while (prog && prog_is_subprog(obj, prog));
+
+	return prog;
+}
+
+void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
+{
+	prog->prog_ifindex = ifindex;
+}
+
+const char *bpf_program__name(const struct bpf_program *prog)
+{
+	return prog->name;
+}
+
+const char *bpf_program__section_name(const struct bpf_program *prog)
+{
+	return prog->sec_name;
+}
+
+bool bpf_program__autoload(const struct bpf_program *prog)
+{
+	return prog->autoload;
+}
+
+int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
+{
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EINVAL);
+
+	prog->autoload = autoload;
+	return 0;
+}
+
+bool bpf_program__autoattach(const struct bpf_program *prog)
+{
+	return prog->autoattach;
+}
+
+void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach)
+{
+	prog->autoattach = autoattach;
+}
+
+const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog)
+{
+	return prog->insns;
+}
+
+size_t bpf_program__insn_cnt(const struct bpf_program *prog)
+{
+	return prog->insns_cnt;
+}
+
+int bpf_program__set_insns(struct bpf_program *prog,
+			   struct bpf_insn *new_insns, size_t new_insn_cnt)
+{
+	struct bpf_insn *insns;
+
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EBUSY);
+
+	insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns));
+	/* NULL is a valid return from reallocarray if the new count is zero */
+	if (!insns && new_insn_cnt) {
+		pr_warn("prog '%s': failed to realloc prog code\n", prog->name);
+		return libbpf_err(-ENOMEM);
+	}
+	memcpy(insns, new_insns, new_insn_cnt * sizeof(*insns));
+
+	prog->insns = insns;
+	prog->insns_cnt = new_insn_cnt;
+	return 0;
+}
+
+int bpf_program__fd(const struct bpf_program *prog)
+{
+	if (!prog)
+		return libbpf_err(-EINVAL);
+
+	if (prog->fd < 0)
+		return libbpf_err(-ENOENT);
+
+	return prog->fd;
+}
+
+__alias(bpf_program__type)
+enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog);
+
+enum bpf_prog_type bpf_program__type(const struct bpf_program *prog)
+{
+	return prog->type;
+}
+
+static size_t custom_sec_def_cnt;
+static struct bpf_sec_def *custom_sec_defs;
+static struct bpf_sec_def custom_fallback_def;
+static bool has_custom_fallback_def;
+static int last_custom_sec_def_handler_id;
+
+int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
+{
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EBUSY);
+
+	/* if type is not changed, do nothing */
+	if (prog->type == type)
+		return 0;
+
+	prog->type = type;
+
+	/* If a program type was changed, we need to reset associated SEC()
+	 * handler, as it will be invalid now. The only exception is a generic
+	 * fallback handler, which by definition is program type-agnostic and
+	 * is a catch-all custom handler, optionally set by the application,
+	 * so should be able to handle any type of BPF program.
+	 */
+	if (prog->sec_def != &custom_fallback_def)
+		prog->sec_def = NULL;
+	return 0;
+}
+
+__alias(bpf_program__expected_attach_type)
+enum bpf_attach_type bpf_program__get_expected_attach_type(const struct bpf_program *prog);
+
+enum bpf_attach_type bpf_program__expected_attach_type(const struct bpf_program *prog)
+{
+	return prog->expected_attach_type;
+}
+
+int bpf_program__set_expected_attach_type(struct bpf_program *prog,
+					   enum bpf_attach_type type)
+{
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EBUSY);
+
+	prog->expected_attach_type = type;
+	return 0;
+}
+
+__u32 bpf_program__flags(const struct bpf_program *prog)
+{
+	return prog->prog_flags;
+}
+
+int bpf_program__set_flags(struct bpf_program *prog, __u32 flags)
+{
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EBUSY);
+
+	prog->prog_flags = flags;
+	return 0;
+}
+
+__u32 bpf_program__log_level(const struct bpf_program *prog)
+{
+	return prog->log_level;
+}
+
+int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level)
+{
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EBUSY);
+
+	prog->log_level = log_level;
+	return 0;
+}
+
+const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size)
+{
+	*log_size = prog->log_size;
+	return prog->log_buf;
+}
+
+int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size)
+{
+	if (log_size && !log_buf)
+		return libbpf_err(-EINVAL);
+	if (prog->log_size > UINT_MAX)
+		return libbpf_err(-EINVAL);
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EBUSY);
+
+	prog->log_buf = log_buf;
+	prog->log_size = log_size;
+	return 0;
+}
+
+struct bpf_func_info *bpf_program__func_info(const struct bpf_program *prog)
+{
+	if (prog->func_info_rec_size != sizeof(struct bpf_func_info))
+		return libbpf_err_ptr(-EOPNOTSUPP);
+	return prog->func_info;
+}
+
+__u32 bpf_program__func_info_cnt(const struct bpf_program *prog)
+{
+	return prog->func_info_cnt;
+}
+
+struct bpf_line_info *bpf_program__line_info(const struct bpf_program *prog)
+{
+	if (prog->line_info_rec_size != sizeof(struct bpf_line_info))
+		return libbpf_err_ptr(-EOPNOTSUPP);
+	return prog->line_info;
+}
+
+__u32 bpf_program__line_info_cnt(const struct bpf_program *prog)
+{
+	return prog->line_info_cnt;
+}
+
+int bpf_program__clone(struct bpf_program *prog, const struct bpf_prog_load_opts *opts)
+{
+	LIBBPF_OPTS(bpf_prog_load_opts, attr);
+	struct bpf_object *obj;
+	const void *info;
+	__u32 info_cnt, info_rec_size;
+	int err, fd, prog_btf_fd;
+
+	if (!prog)
+		return libbpf_err(-EINVAL);
+
+	if (!OPTS_VALID(opts, bpf_prog_load_opts))
+		return libbpf_err(-EINVAL);
+
+	obj = prog->obj;
+	if (obj->state < OBJ_PREPARED)
+		return libbpf_err(-EINVAL);
+
+	/*
+	 * Caller-provided opts take priority; fall back to
+	 * prog/object defaults when the caller leaves them zero.
+	 */
+	attr.attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0) ?: prog->attach_prog_fd;
+	attr.prog_flags = OPTS_GET(opts, prog_flags, 0) ?: prog->prog_flags;
+	attr.prog_ifindex = OPTS_GET(opts, prog_ifindex, 0) ?: prog->prog_ifindex;
+	attr.kern_version = OPTS_GET(opts, kern_version, 0) ?: obj->kern_version;
+	attr.fd_array = OPTS_GET(opts, fd_array, NULL) ?: obj->fd_array;
+	attr.fd_array_cnt = OPTS_GET(opts, fd_array_cnt, 0) ?: obj->fd_array_cnt;
+	attr.token_fd = OPTS_GET(opts, token_fd, 0) ?: obj->token_fd;
+	if (attr.token_fd)
+		attr.prog_flags |= BPF_F_TOKEN_FD;
+
+	prog_btf_fd = OPTS_GET(opts, prog_btf_fd, 0);
+	if (!prog_btf_fd && obj->btf)
+		prog_btf_fd = btf__fd(obj->btf);
+
+	/* BTF func/line info: only pass if kernel supports it */
+	if (kernel_supports(obj, FEAT_BTF_FUNC) && prog_btf_fd > 0) {
+		attr.prog_btf_fd = prog_btf_fd;
+
+		/* func_info/line_info triples: all-or-nothing from caller */
+		info = OPTS_GET(opts, func_info, NULL);
+		info_cnt = OPTS_GET(opts, func_info_cnt, 0);
+		info_rec_size = OPTS_GET(opts, func_info_rec_size, 0);
+		if (!!info != !!info_cnt || !!info != !!info_rec_size) {
+			pr_warn("prog '%s': func_info, func_info_cnt, and func_info_rec_size must all be specified or all omitted\n",
+				prog->name);
+			return libbpf_err(-EINVAL);
+		}
+		attr.func_info = info ?: prog->func_info;
+		attr.func_info_cnt = info ? info_cnt : prog->func_info_cnt;
+		attr.func_info_rec_size = info ? info_rec_size : prog->func_info_rec_size;
+
+		info = OPTS_GET(opts, line_info, NULL);
+		info_cnt = OPTS_GET(opts, line_info_cnt, 0);
+		info_rec_size = OPTS_GET(opts, line_info_rec_size, 0);
+		if (!!info != !!info_cnt || !!info != !!info_rec_size) {
+			pr_warn("prog '%s': line_info, line_info_cnt, and line_info_rec_size must all be specified or all omitted\n",
+				prog->name);
+			return libbpf_err(-EINVAL);
+		}
+		attr.line_info = info ?: prog->line_info;
+		attr.line_info_cnt = info ? info_cnt : prog->line_info_cnt;
+		attr.line_info_rec_size = info ? info_rec_size : prog->line_info_rec_size;
+	}
+
+	/* Logging is caller-controlled; no fallback to prog/obj log settings */
+	attr.log_buf = OPTS_GET(opts, log_buf, NULL);
+	attr.log_size = OPTS_GET(opts, log_size, 0);
+	attr.log_level = OPTS_GET(opts, log_level, 0);
+
+	/*
+	 * Fields below may be mutated by prog_prepare_load_fn:
+	 * Seed them from prog/obj defaults here;
+	 * Later override with caller-provided opts.
+	 */
+	attr.expected_attach_type = prog->expected_attach_type;
+	attr.attach_btf_id = prog->attach_btf_id;
+	attr.attach_btf_obj_fd = prog->attach_btf_obj_fd;
+
+	if (prog->sec_def && prog->sec_def->prog_prepare_load_fn) {
+		err = prog->sec_def->prog_prepare_load_fn(prog, &attr, prog->sec_def->cookie);
+		if (err)
+			return libbpf_err(err);
+	}
+
+	/* Re-apply caller overrides for output fields */
+	if (OPTS_GET(opts, expected_attach_type, 0))
+		attr.expected_attach_type = OPTS_GET(opts, expected_attach_type, 0);
+	if (OPTS_GET(opts, attach_btf_id, 0))
+		attr.attach_btf_id = OPTS_GET(opts, attach_btf_id, 0);
+	if (OPTS_GET(opts, attach_btf_obj_fd, 0))
+		attr.attach_btf_obj_fd = OPTS_GET(opts, attach_btf_obj_fd, 0);
+
+	/*
+	 * Unlike bpf_object_load_prog(), we intentionally do not call bpf_prog_bind_map()
+	 * for RODATA maps here to avoid mutating the object's state. Callers can bind the
+	 * required maps themselves using bpf_prog_bind_map().
+	 */
+	fd = bpf_prog_load(prog->type, prog->name, obj->license, prog->insns, prog->insns_cnt,
+			   &attr);
+
+	return libbpf_err(fd);
+}
+
+#define SEC_DEF(sec_pfx, ptype, atype, flags, ...) {			    \
+	.sec = (char *)sec_pfx,						    \
+	.prog_type = BPF_PROG_TYPE_##ptype,				    \
+	.expected_attach_type = atype,					    \
+	.cookie = (long)(flags),					    \
+	.prog_prepare_load_fn = libbpf_prepare_prog_load,		    \
+	__VA_ARGS__							    \
+}
+
+static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_kprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_tracing_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+
+static const struct bpf_sec_def section_defs[] = {
+	SEC_DEF("socket",		SOCKET_FILTER, 0, SEC_NONE),
+	SEC_DEF("sk_reuseport/migrate",	SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE),
+	SEC_DEF("sk_reuseport",		SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE),
+	SEC_DEF("kprobe+",		KPROBE,	0, SEC_NONE, attach_kprobe),
+	SEC_DEF("uprobe+",		KPROBE,	0, SEC_NONE, attach_uprobe),
+	SEC_DEF("uprobe.s+",		KPROBE,	0, SEC_SLEEPABLE, attach_uprobe),
+	SEC_DEF("kretprobe+",		KPROBE, 0, SEC_NONE, attach_kprobe),
+	SEC_DEF("uretprobe+",		KPROBE, 0, SEC_NONE, attach_uprobe),
+	SEC_DEF("uretprobe.s+",		KPROBE, 0, SEC_SLEEPABLE, attach_uprobe),
+	SEC_DEF("kprobe.multi+",	KPROBE,	BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
+	SEC_DEF("kretprobe.multi+",	KPROBE,	BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
+	SEC_DEF("kprobe.session+",	KPROBE,	BPF_TRACE_KPROBE_SESSION, SEC_NONE, attach_kprobe_session),
+	SEC_DEF("uprobe.multi+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
+	SEC_DEF("uretprobe.multi+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
+	SEC_DEF("uprobe.session+",	KPROBE,	BPF_TRACE_UPROBE_SESSION, SEC_NONE, attach_uprobe_multi),
+	SEC_DEF("uprobe.multi.s+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
+	SEC_DEF("uretprobe.multi.s+",	KPROBE,	BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
+	SEC_DEF("uprobe.session.s+",	KPROBE,	BPF_TRACE_UPROBE_SESSION, SEC_SLEEPABLE, attach_uprobe_multi),
+	SEC_DEF("ksyscall+",		KPROBE,	0, SEC_NONE, attach_ksyscall),
+	SEC_DEF("kretsyscall+",		KPROBE, 0, SEC_NONE, attach_ksyscall),
+	SEC_DEF("usdt+",		KPROBE,	0, SEC_USDT, attach_usdt),
+	SEC_DEF("usdt.s+",		KPROBE,	0, SEC_USDT | SEC_SLEEPABLE, attach_usdt),
+	SEC_DEF("tc/ingress",		SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), /* alias for tcx */
+	SEC_DEF("tc/egress",		SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE),  /* alias for tcx */
+	SEC_DEF("tcx/ingress",		SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE),
+	SEC_DEF("tcx/egress",		SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE),
+	SEC_DEF("tc",			SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */
+	SEC_DEF("classifier",		SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */
+	SEC_DEF("action",		SCHED_ACT, 0, SEC_NONE), /* deprecated / legacy, use tcx */
+	SEC_DEF("netkit/primary",	SCHED_CLS, BPF_NETKIT_PRIMARY, SEC_NONE),
+	SEC_DEF("netkit/peer",		SCHED_CLS, BPF_NETKIT_PEER, SEC_NONE),
+	SEC_DEF("tracepoint+",		TRACEPOINT, 0, SEC_NONE, attach_tp),
+	SEC_DEF("tp+",			TRACEPOINT, 0, SEC_NONE, attach_tp),
+	SEC_DEF("tracepoint.s+",	TRACEPOINT, 0, SEC_SLEEPABLE, attach_tp),
+	SEC_DEF("tp.s+",		TRACEPOINT, 0, SEC_SLEEPABLE, attach_tp),
+	SEC_DEF("raw_tracepoint+",	RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
+	SEC_DEF("raw_tp+",		RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),
+	SEC_DEF("raw_tracepoint.s+",	RAW_TRACEPOINT, 0, SEC_SLEEPABLE, attach_raw_tp),
+	SEC_DEF("raw_tp.s+",		RAW_TRACEPOINT, 0, SEC_SLEEPABLE, attach_raw_tp),
+	SEC_DEF("raw_tracepoint.w+",	RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp),
+	SEC_DEF("raw_tp.w+",		RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp),
+	SEC_DEF("tp_btf+",		TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("tp_btf.s+",		TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fentry+",		TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fmod_ret+",		TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fexit+",		TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fentry.s+",		TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fmod_ret.s+",		TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fexit.s+",		TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fsession+",		TRACING, BPF_TRACE_FSESSION, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("fsession.s+",		TRACING, BPF_TRACE_FSESSION, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
+	SEC_DEF("fsession.multi+",	TRACING, BPF_TRACE_FSESSION_MULTI, 0, attach_tracing_multi),
+	SEC_DEF("fsession.multi.s+",	TRACING, BPF_TRACE_FSESSION_MULTI, SEC_SLEEPABLE, attach_tracing_multi),
+	SEC_DEF("fentry.multi+",	TRACING, BPF_TRACE_FENTRY_MULTI, 0, attach_tracing_multi),
+	SEC_DEF("fexit.multi+",		TRACING, BPF_TRACE_FEXIT_MULTI, 0, attach_tracing_multi),
+	SEC_DEF("fentry.multi.s+",	TRACING, BPF_TRACE_FENTRY_MULTI, SEC_SLEEPABLE, attach_tracing_multi),
+	SEC_DEF("fexit.multi.s+",	TRACING, BPF_TRACE_FEXIT_MULTI, SEC_SLEEPABLE, attach_tracing_multi),
+	SEC_DEF("freplace+",		EXT, 0, SEC_ATTACH_BTF, attach_trace),
+	SEC_DEF("lsm+",			LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm),
+	SEC_DEF("lsm.s+",		LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm),
+	SEC_DEF("lsm_cgroup+",		LSM, BPF_LSM_CGROUP, SEC_ATTACH_BTF),
+	SEC_DEF("iter+",		TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter),
+	SEC_DEF("iter.s+",		TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_iter),
+	SEC_DEF("syscall",		SYSCALL, 0, SEC_SLEEPABLE),
+	SEC_DEF("xdp.frags/devmap",	XDP, BPF_XDP_DEVMAP, SEC_XDP_FRAGS),
+	SEC_DEF("xdp/devmap",		XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE),
+	SEC_DEF("xdp.frags/cpumap",	XDP, BPF_XDP_CPUMAP, SEC_XDP_FRAGS),
+	SEC_DEF("xdp/cpumap",		XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE),
+	SEC_DEF("xdp.frags",		XDP, BPF_XDP, SEC_XDP_FRAGS),
+	SEC_DEF("xdp",			XDP, BPF_XDP, SEC_ATTACHABLE_OPT),
+	SEC_DEF("perf_event",		PERF_EVENT, 0, SEC_NONE),
+	SEC_DEF("lwt_in",		LWT_IN, 0, SEC_NONE),
+	SEC_DEF("lwt_out",		LWT_OUT, 0, SEC_NONE),
+	SEC_DEF("lwt_xmit",		LWT_XMIT, 0, SEC_NONE),
+	SEC_DEF("lwt_seg6local",	LWT_SEG6LOCAL, 0, SEC_NONE),
+	SEC_DEF("sockops",		SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sk_skb/stream_parser",	SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sk_skb/verdict",	SK_SKB, BPF_SK_SKB_VERDICT, SEC_ATTACHABLE_OPT),
+	SEC_DEF("sk_skb",		SK_SKB, 0, SEC_NONE),
+	SEC_DEF("sk_msg",		SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT),
+	SEC_DEF("lirc_mode2",		LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT),
+	SEC_DEF("flow_dissector",	FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup_skb/ingress",	CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup_skb/egress",	CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup/skb",		CGROUP_SKB, 0, SEC_NONE),
+	SEC_DEF("cgroup/sock_create",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sock_release",	CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sock",		CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT),
+	SEC_DEF("cgroup/post_bind4",	CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/post_bind6",	CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/bind4",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/bind6",		CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/connect4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/connect6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/connect_unix",	CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_CONNECT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sendmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sendmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sendmsg_unix",	CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_SENDMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/recvmsg4",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/recvmsg6",	CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/recvmsg_unix",	CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_RECVMSG, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getpeername4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getpeername6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getpeername_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_GETPEERNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockname4",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockname6",	CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockname_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_GETSOCKNAME, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/sysctl",	CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/getsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/setsockopt",	CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE),
+	SEC_DEF("cgroup/dev",		CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT),
+	SEC_DEF("struct_ops+",		STRUCT_OPS, 0, SEC_NONE),
+	SEC_DEF("struct_ops.s+",	STRUCT_OPS, 0, SEC_SLEEPABLE),
+	SEC_DEF("sk_lookup",		SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),
+	SEC_DEF("netfilter",		NETFILTER, BPF_NETFILTER, SEC_NONE),
+};
+
+int libbpf_register_prog_handler(const char *sec,
+				 enum bpf_prog_type prog_type,
+				 enum bpf_attach_type exp_attach_type,
+				 const struct libbpf_prog_handler_opts *opts)
+{
+	struct bpf_sec_def *sec_def;
+
+	if (!OPTS_VALID(opts, libbpf_prog_handler_opts))
+		return libbpf_err(-EINVAL);
+
+	if (last_custom_sec_def_handler_id == INT_MAX) /* prevent overflow */
+		return libbpf_err(-E2BIG);
+
+	if (sec) {
+		sec_def = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt + 1,
+					      sizeof(*sec_def));
+		if (!sec_def)
+			return libbpf_err(-ENOMEM);
+
+		custom_sec_defs = sec_def;
+		sec_def = &custom_sec_defs[custom_sec_def_cnt];
+	} else {
+		if (has_custom_fallback_def)
+			return libbpf_err(-EBUSY);
+
+		sec_def = &custom_fallback_def;
+	}
+
+	sec_def->sec = sec ? strdup(sec) : NULL;
+	if (sec && !sec_def->sec)
+		return libbpf_err(-ENOMEM);
+
+	sec_def->prog_type = prog_type;
+	sec_def->expected_attach_type = exp_attach_type;
+	sec_def->cookie = OPTS_GET(opts, cookie, 0);
+
+	sec_def->prog_setup_fn = OPTS_GET(opts, prog_setup_fn, NULL);
+	sec_def->prog_prepare_load_fn = OPTS_GET(opts, prog_prepare_load_fn, NULL);
+	sec_def->prog_attach_fn = OPTS_GET(opts, prog_attach_fn, NULL);
+
+	sec_def->handler_id = ++last_custom_sec_def_handler_id;
+
+	if (sec)
+		custom_sec_def_cnt++;
+	else
+		has_custom_fallback_def = true;
+
+	return sec_def->handler_id;
+}
+
+int libbpf_unregister_prog_handler(int handler_id)
+{
+	struct bpf_sec_def *sec_defs;
+	int i;
+
+	if (handler_id <= 0)
+		return libbpf_err(-EINVAL);
+
+	if (has_custom_fallback_def && custom_fallback_def.handler_id == handler_id) {
+		memset(&custom_fallback_def, 0, sizeof(custom_fallback_def));
+		has_custom_fallback_def = false;
+		return 0;
+	}
+
+	for (i = 0; i < custom_sec_def_cnt; i++) {
+		if (custom_sec_defs[i].handler_id == handler_id)
+			break;
+	}
+
+	if (i == custom_sec_def_cnt)
+		return libbpf_err(-ENOENT);
+
+	free(custom_sec_defs[i].sec);
+	for (i = i + 1; i < custom_sec_def_cnt; i++)
+		custom_sec_defs[i - 1] = custom_sec_defs[i];
+	custom_sec_def_cnt--;
+
+	/* try to shrink the array, but it's ok if we couldn't */
+	sec_defs = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt, sizeof(*sec_defs));
+	/* if new count is zero, reallocarray can return a valid NULL result;
+	 * in this case the previous pointer will be freed, so we *have to*
+	 * reassign old pointer to the new value (even if it's NULL)
+	 */
+	if (sec_defs || custom_sec_def_cnt == 0)
+		custom_sec_defs = sec_defs;
+
+	return 0;
+}
+
+static bool sec_def_matches(const struct bpf_sec_def *sec_def, const char *sec_name)
+{
+	size_t len = strlen(sec_def->sec);
+
+	/* "type/" always has to have proper SEC("type/extras") form */
+	if (sec_def->sec[len - 1] == '/') {
+		if (str_has_pfx(sec_name, sec_def->sec))
+			return true;
+		return false;
+	}
+
+	/* "type+" means it can be either exact SEC("type") or
+	 * well-formed SEC("type/extras") with proper '/' separator
+	 */
+	if (sec_def->sec[len - 1] == '+') {
+		len--;
+		/* not even a prefix */
+		if (strncmp(sec_name, sec_def->sec, len) != 0)
+			return false;
+		/* exact match or has '/' separator */
+		if (sec_name[len] == '\0' || sec_name[len] == '/')
+			return true;
+		return false;
+	}
+
+	return strcmp(sec_name, sec_def->sec) == 0;
+}
+
+static const struct bpf_sec_def *find_sec_def(const char *sec_name)
+{
+	const struct bpf_sec_def *sec_def;
+	int i, n;
+
+	n = custom_sec_def_cnt;
+	for (i = 0; i < n; i++) {
+		sec_def = &custom_sec_defs[i];
+		if (sec_def_matches(sec_def, sec_name))
+			return sec_def;
+	}
+
+	n = ARRAY_SIZE(section_defs);
+	for (i = 0; i < n; i++) {
+		sec_def = &section_defs[i];
+		if (sec_def_matches(sec_def, sec_name))
+			return sec_def;
+	}
+
+	if (has_custom_fallback_def)
+		return &custom_fallback_def;
+
+	return NULL;
+}
+
+#define MAX_TYPE_NAME_SIZE 32
+
+static char *libbpf_get_type_names(bool attach_type)
+{
+	int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
+	char *buf;
+
+	buf = malloc(len);
+	if (!buf)
+		return NULL;
+
+	buf[0] = '\0';
+	/* Forge string buf with all available names */
+	for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
+		const struct bpf_sec_def *sec_def = &section_defs[i];
+
+		if (attach_type) {
+			if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load)
+				continue;
+
+			if (!(sec_def->cookie & SEC_ATTACHABLE))
+				continue;
+		}
+
+		if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
+			free(buf);
+			return NULL;
+		}
+		strcat(buf, " ");
+		strcat(buf, section_defs[i].sec);
+	}
+
+	return buf;
+}
+
+int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+			     enum bpf_attach_type *expected_attach_type)
+{
+	const struct bpf_sec_def *sec_def;
+	char *type_names;
+
+	if (!name)
+		return libbpf_err(-EINVAL);
+
+	sec_def = find_sec_def(name);
+	if (sec_def) {
+		*prog_type = sec_def->prog_type;
+		*expected_attach_type = sec_def->expected_attach_type;
+		return 0;
+	}
+
+	pr_debug("failed to guess program type from ELF section '%s'\n", name);
+	type_names = libbpf_get_type_names(false);
+	if (type_names != NULL) {
+		pr_debug("supported section(type) names are:%s\n", type_names);
+		free(type_names);
+	}
+
+	return libbpf_err(-ESRCH);
+}
+
+const char *libbpf_bpf_attach_type_str(enum bpf_attach_type t)
+{
+	if (t < 0 || t >= ARRAY_SIZE(attach_type_name))
+		return NULL;
+
+	return attach_type_name[t];
+}
+
+const char *libbpf_bpf_link_type_str(enum bpf_link_type t)
+{
+	if (t < 0 || t >= ARRAY_SIZE(link_type_name))
+		return NULL;
+
+	return link_type_name[t];
+}
+
+const char *libbpf_bpf_map_type_str(enum bpf_map_type t)
+{
+	if (t < 0 || t >= ARRAY_SIZE(map_type_name))
+		return NULL;
+
+	return map_type_name[t];
+}
+
+const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t)
+{
+	if (t < 0 || t >= ARRAY_SIZE(prog_type_name))
+		return NULL;
+
+	return prog_type_name[t];
+}
+
+static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
+						     int sec_idx,
+						     size_t offset)
+{
+	struct bpf_map *map;
+	size_t i;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		map = &obj->maps[i];
+		if (!bpf_map__is_struct_ops(map))
+			continue;
+		if (map->sec_idx == sec_idx &&
+		    map->sec_offset <= offset &&
+		    offset - map->sec_offset < map->def.value_size)
+			return map;
+	}
+
+	return NULL;
+}
+
+/* Collect the reloc from ELF, populate the st_ops->progs[], and update
+ * st_ops->data for shadow type.
+ */
+static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
+					    Elf64_Shdr *shdr, Elf_Data *data)
+{
+	const struct btf_type *type;
+	const struct btf_member *member;
+	struct bpf_struct_ops *st_ops;
+	struct bpf_program *prog;
+	unsigned int shdr_idx;
+	const struct btf *btf;
+	struct bpf_map *map;
+	unsigned int moff, insn_idx;
+	const char *name;
+	__u32 member_idx;
+	Elf64_Sym *sym;
+	Elf64_Rel *rel;
+	int i, nrels;
+
+	btf = obj->btf;
+	nrels = shdr->sh_size / shdr->sh_entsize;
+	for (i = 0; i < nrels; i++) {
+		rel = elf_rel_by_idx(data, i);
+		if (!rel) {
+			pr_warn("struct_ops reloc: failed to get %d reloc\n", i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info));
+		if (!sym) {
+			pr_warn("struct_ops reloc: symbol %zx not found\n",
+				(size_t)ELF64_R_SYM(rel->r_info));
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		name = elf_sym_str(obj, sym->st_name) ?: "<?>";
+		map = find_struct_ops_map_by_offset(obj, shdr->sh_info, rel->r_offset);
+		if (!map) {
+			pr_warn("struct_ops reloc: cannot find map at rel->r_offset %zu\n",
+				(size_t)rel->r_offset);
+			return -EINVAL;
+		}
+
+		moff = rel->r_offset - map->sec_offset;
+		shdr_idx = sym->st_shndx;
+		st_ops = map->st_ops;
+		pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel->r_offset %zu map->sec_offset %zu name %u (\'%s\')\n",
+			 map->name,
+			 (long long)(rel->r_info >> 32),
+			 (long long)sym->st_value,
+			 shdr_idx, (size_t)rel->r_offset,
+			 map->sec_offset, sym->st_name, name);
+
+		if (shdr_idx >= SHN_LORESERVE) {
+			pr_warn("struct_ops reloc %s: rel->r_offset %zu shdr_idx %u unsupported non-static function\n",
+				map->name, (size_t)rel->r_offset, shdr_idx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		if (sym->st_value % BPF_INSN_SZ) {
+			pr_warn("struct_ops reloc %s: invalid target program offset %llu\n",
+				map->name, (unsigned long long)sym->st_value);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+		insn_idx = sym->st_value / BPF_INSN_SZ;
+
+		type = btf__type_by_id(btf, st_ops->type_id);
+		member = find_member_by_offset(type, moff * 8);
+		if (!member) {
+			pr_warn("struct_ops reloc %s: cannot find member at moff %u\n",
+				map->name, moff);
+			return -EINVAL;
+		}
+		member_idx = member - btf_members(type);
+		name = btf__name_by_offset(btf, member->name_off);
+
+		if (!resolve_func_ptr(btf, member->type, NULL)) {
+			pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n",
+				map->name, name);
+			return -EINVAL;
+		}
+
+		prog = find_prog_by_sec_insn(obj, shdr_idx, insn_idx);
+		if (!prog) {
+			pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n",
+				map->name, shdr_idx, name);
+			return -EINVAL;
+		}
+
+		/* prevent the use of BPF prog with invalid type */
+		if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) {
+			pr_warn("struct_ops reloc %s: prog %s is not struct_ops BPF program\n",
+				map->name, prog->name);
+			return -EINVAL;
+		}
+
+		st_ops->progs[member_idx] = prog;
+
+		/* st_ops->data will be exposed to users, being returned by
+		 * bpf_map__initial_value() as a pointer to the shadow
+		 * type. All function pointers in the original struct type
+		 * should be converted to a pointer to struct bpf_program
+		 * in the shadow type.
+		 */
+		*((struct bpf_program **)(st_ops->data + moff)) = prog;
+	}
+
+	return 0;
+}
+
+#define BTF_TRACE_PREFIX "btf_trace_"
+#define BTF_LSM_PREFIX "bpf_lsm_"
+#define BTF_ITER_PREFIX "bpf_iter_"
+#define BTF_MAX_NAME_SIZE 128
+
+void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
+				const char **prefix, int *kind)
+{
+	switch (attach_type) {
+	case BPF_TRACE_RAW_TP:
+		*prefix = BTF_TRACE_PREFIX;
+		*kind = BTF_KIND_TYPEDEF;
+		break;
+	case BPF_LSM_MAC:
+	case BPF_LSM_CGROUP:
+		*prefix = BTF_LSM_PREFIX;
+		*kind = BTF_KIND_FUNC;
+		break;
+	case BPF_TRACE_ITER:
+		*prefix = BTF_ITER_PREFIX;
+		*kind = BTF_KIND_FUNC;
+		break;
+	default:
+		*prefix = "";
+		*kind = BTF_KIND_FUNC;
+	}
+}
+
+static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
+				   const char *name, __u32 kind)
+{
+	char btf_type_name[BTF_MAX_NAME_SIZE];
+	int ret;
+
+	ret = snprintf(btf_type_name, sizeof(btf_type_name),
+		       "%s%s", prefix, name);
+	/* snprintf returns the number of characters written excluding the
+	 * terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it
+	 * indicates truncation.
+	 */
+	if (ret < 0 || ret >= sizeof(btf_type_name))
+		return -ENAMETOOLONG;
+	return btf__find_by_name_kind(btf, btf_type_name, kind);
+}
+
+static inline int find_attach_btf_id(struct btf *btf, const char *name,
+				     enum bpf_attach_type attach_type)
+{
+	const char *prefix;
+	int kind;
+
+	btf_get_kernel_prefix_kind(attach_type, &prefix, &kind);
+	return find_btf_by_prefix_kind(btf, prefix, name, kind);
+}
+
+int libbpf_find_vmlinux_btf_id(const char *name,
+			       enum bpf_attach_type attach_type)
+{
+	struct btf *btf;
+	int err;
+
+	btf = btf__load_vmlinux_btf();
+	err = libbpf_get_error(btf);
+	if (err) {
+		pr_warn("vmlinux BTF is not found\n");
+		return libbpf_err(err);
+	}
+
+	err = find_attach_btf_id(btf, name, attach_type);
+	if (err <= 0)
+		pr_warn("%s is not found in vmlinux BTF\n", name);
+
+	btf__free(btf);
+	return libbpf_err(err);
+}
+
+static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd, int token_fd)
+{
+	struct bpf_prog_info info;
+	__u32 info_len = sizeof(info);
+	struct btf *btf;
+	int err;
+
+	memset(&info, 0, info_len);
+	err = bpf_prog_get_info_by_fd(attach_prog_fd, &info, &info_len);
+	if (err) {
+		pr_warn("failed bpf_prog_get_info_by_fd for FD %u: %s\n",
+			attach_prog_fd, errstr(err));
+		return err;
+	}
+
+	err = -EINVAL;
+	if (!info.btf_id) {
+		pr_warn("The target program doesn't have BTF\n");
+		goto out;
+	}
+	btf = btf_load_from_kernel(info.btf_id, NULL, token_fd);
+	err = libbpf_get_error(btf);
+	if (err) {
+		pr_warn("Failed to get BTF %u of the program: %s\n", info.btf_id, errstr(err));
+		goto out;
+	}
+	err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
+	btf__free(btf);
+	if (err <= 0) {
+		pr_warn("%s is not found in prog's BTF\n", name);
+		goto out;
+	}
+out:
+	return err;
+}
+
+static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
+			      enum bpf_attach_type attach_type,
+			      int *btf_obj_fd, int *btf_type_id)
+{
+	int ret, i, mod_len = 0;
+	const char *fn_name, *mod_name = NULL;
+
+	fn_name = strchr(attach_name, ':');
+	if (fn_name) {
+		mod_name = attach_name;
+		mod_len = fn_name - mod_name;
+		fn_name++;
+	}
+
+	if (!mod_name || strncmp(mod_name, "vmlinux", mod_len) == 0) {
+		ret = find_attach_btf_id(obj->btf_vmlinux,
+					 mod_name ? fn_name : attach_name,
+					 attach_type);
+		if (ret > 0) {
+			*btf_obj_fd = 0; /* vmlinux BTF */
+			*btf_type_id = ret;
+			return 0;
+		}
+		if (ret != -ENOENT)
+			return ret;
+	}
+
+	ret = load_module_btfs(obj);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < obj->btf_module_cnt; i++) {
+		const struct module_btf *mod = &obj->btf_modules[i];
+
+		if (mod_name && strncmp(mod->name, mod_name, mod_len) != 0)
+			continue;
+
+		ret = find_attach_btf_id(mod->btf,
+					 mod_name ? fn_name : attach_name,
+					 attach_type);
+		if (ret > 0) {
+			*btf_obj_fd = mod->fd;
+			*btf_type_id = ret;
+			return 0;
+		}
+		if (ret == -ENOENT)
+			continue;
+
+		return ret;
+	}
+
+	return -ESRCH;
+}
+
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name,
+				     int *btf_obj_fd, int *btf_type_id)
+{
+	enum bpf_attach_type attach_type = prog->expected_attach_type;
+	__u32 attach_prog_fd = prog->attach_prog_fd;
+	int err = 0;
+
+	/* BPF program's BTF ID */
+	if (prog->type == BPF_PROG_TYPE_EXT || attach_prog_fd) {
+		if (!attach_prog_fd) {
+			pr_warn("prog '%s': attach program FD is not set\n", prog->name);
+			return -EINVAL;
+		}
+		err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd, prog->obj->token_fd);
+		if (err < 0) {
+			pr_warn("prog '%s': failed to find BPF program (FD %u) BTF ID for '%s': %s\n",
+				prog->name, attach_prog_fd, attach_name, errstr(err));
+			return err;
+		}
+		*btf_obj_fd = 0;
+		*btf_type_id = err;
+		return 0;
+	}
+
+	/* kernel/module BTF ID */
+	if (prog->obj->gen_loader) {
+		bpf_gen__record_attach_target(prog->obj->gen_loader, attach_name, attach_type);
+		*btf_obj_fd = 0;
+		*btf_type_id = 1;
+	} else {
+		err = find_kernel_btf_id(prog->obj, attach_name,
+					 attach_type, btf_obj_fd,
+					 btf_type_id);
+	}
+	if (err) {
+		pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %s\n",
+			prog->name, attach_name, errstr(err));
+		return err;
+	}
+	return 0;
+}
+
+int libbpf_attach_type_by_name(const char *name,
+			       enum bpf_attach_type *attach_type)
+{
+	char *type_names;
+	const struct bpf_sec_def *sec_def;
+
+	if (!name)
+		return libbpf_err(-EINVAL);
+
+	sec_def = find_sec_def(name);
+	if (!sec_def) {
+		pr_debug("failed to guess attach type based on ELF section name '%s'\n", name);
+		type_names = libbpf_get_type_names(true);
+		if (type_names != NULL) {
+			pr_debug("attachable section(type) names are:%s\n", type_names);
+			free(type_names);
+		}
+
+		return libbpf_err(-EINVAL);
+	}
+
+	if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load)
+		return libbpf_err(-EINVAL);
+	if (!(sec_def->cookie & SEC_ATTACHABLE))
+		return libbpf_err(-EINVAL);
+
+	*attach_type = sec_def->expected_attach_type;
+	return 0;
+}
+
+int bpf_map__fd(const struct bpf_map *map)
+{
+	if (!map)
+		return libbpf_err(-EINVAL);
+	if (!map_is_created(map))
+		return -1;
+	return map->fd;
+}
+
+static bool map_uses_real_name(const struct bpf_map *map)
+{
+	/* Since libbpf started to support custom .data.* and .rodata.* maps,
+	 * their user-visible name differs from kernel-visible name. Users see
+	 * such map's corresponding ELF section name as a map name.
+	 * This check distinguishes .data/.rodata from .data.* and .rodata.*
+	 * maps to know which name has to be returned to the user.
+	 * Map name of the custom .percpu.* maps might be truncated to
+	 * BPF_OBJ_NAME_LEN-1 chars in internal_map_name(). Hence, percpu data
+	 * maps must use real name for their user-visible name.
+	 */
+	if (map->libbpf_type == LIBBPF_MAP_DATA && strcmp(map->real_name, DATA_SEC) != 0)
+		return true;
+	if (map->libbpf_type == LIBBPF_MAP_RODATA && strcmp(map->real_name, RODATA_SEC) != 0)
+		return true;
+	if (map->libbpf_type == LIBBPF_MAP_PERCPU)
+		return true;
+	return false;
+}
+
+const char *bpf_map__name(const struct bpf_map *map)
+{
+	if (!map)
+		return NULL;
+
+	if (map_uses_real_name(map))
+		return map->real_name;
+
+	return map->name;
+}
+
+enum bpf_map_type bpf_map__type(const struct bpf_map *map)
+{
+	return map->def.type;
+}
+
+int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+	map->def.type = type;
+	return 0;
+}
+
+__u32 bpf_map__map_flags(const struct bpf_map *map)
+{
+	return map->def.map_flags;
+}
+
+int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+	map->def.map_flags = flags;
+	return 0;
+}
+
+__u64 bpf_map__map_extra(const struct bpf_map *map)
+{
+	return map->map_extra;
+}
+
+int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+	map->map_extra = map_extra;
+	return 0;
+}
+
+__u32 bpf_map__numa_node(const struct bpf_map *map)
+{
+	return map->numa_node;
+}
+
+int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+	map->numa_node = numa_node;
+	return 0;
+}
+
+__u32 bpf_map__key_size(const struct bpf_map *map)
+{
+	return map->def.key_size;
+}
+
+int bpf_map__set_key_size(struct bpf_map *map, __u32 size)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+	map->def.key_size = size;
+	return 0;
+}
+
+__u32 bpf_map__value_size(const struct bpf_map *map)
+{
+	return map->def.value_size;
+}
+
+static int map_btf_datasec_resize(struct bpf_map *map, __u32 size)
+{
+	struct btf *btf;
+	struct btf_type *datasec_type, *var_type;
+	struct btf_var_secinfo *var;
+	const struct btf_type *array_type;
+	const struct btf_array *array;
+	int vlen, element_sz, new_array_id;
+	__u32 nr_elements;
+
+	/* check btf existence */
+	btf = bpf_object__btf(map->obj);
+	if (!btf)
+		return -ENOENT;
+
+	/* verify map is datasec */
+	datasec_type = btf_type_by_id(btf, bpf_map__btf_value_type_id(map));
+	if (!btf_is_datasec(datasec_type)) {
+		pr_warn("map '%s': cannot be resized, map value type is not a datasec\n",
+			bpf_map__name(map));
+		return -EINVAL;
+	}
+
+	/* verify datasec has at least one var */
+	vlen = btf_vlen(datasec_type);
+	if (vlen == 0) {
+		pr_warn("map '%s': cannot be resized, map value datasec is empty\n",
+			bpf_map__name(map));
+		return -EINVAL;
+	}
+
+	/* verify last var in the datasec is an array */
+	var = &btf_var_secinfos(datasec_type)[vlen - 1];
+	var_type = btf_type_by_id(btf, var->type);
+	array_type = skip_mods_and_typedefs(btf, var_type->type, NULL);
+	if (!btf_is_array(array_type)) {
+		pr_warn("map '%s': cannot be resized, last var must be an array\n",
+			bpf_map__name(map));
+		return -EINVAL;
+	}
+
+	/* verify request size aligns with array */
+	array = btf_array(array_type);
+	element_sz = btf__resolve_size(btf, array->type);
+	if (element_sz <= 0 || (size - var->offset) % element_sz != 0) {
+		pr_warn("map '%s': cannot be resized, element size (%d) doesn't align with new total size (%u)\n",
+			bpf_map__name(map), element_sz, size);
+		return -EINVAL;
+	}
+
+	/* create a new array based on the existing array, but with new length */
+	nr_elements = (size - var->offset) / element_sz;
+	new_array_id = btf__add_array(btf, array->index_type, array->type, nr_elements);
+	if (new_array_id < 0)
+		return new_array_id;
+
+	/* adding a new btf type invalidates existing pointers to btf objects,
+	 * so refresh pointers before proceeding
+	 */
+	datasec_type = btf_type_by_id(btf, map->btf_value_type_id);
+	var = &btf_var_secinfos(datasec_type)[vlen - 1];
+	var_type = btf_type_by_id(btf, var->type);
+
+	/* finally update btf info */
+	datasec_type->size = size;
+	var->size = size - var->offset;
+	var_type->type = new_array_id;
+
+	return 0;
+}
+
+int bpf_map__set_value_size(struct bpf_map *map, __u32 size)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+
+	if (map->mmaped) {
+		size_t mmap_old_sz, mmap_new_sz;
+		int err;
+
+		if (map->def.type != BPF_MAP_TYPE_ARRAY &&
+		    map->def.type != BPF_MAP_TYPE_PERCPU_ARRAY)
+			return libbpf_err(-EOPNOTSUPP);
+
+		mmap_old_sz = bpf_map_mmap_sz(map);
+		mmap_new_sz = array_map_mmap_sz(size, map->def.max_entries);
+		err = bpf_map_mmap_resize(map, mmap_old_sz, mmap_new_sz);
+		if (err) {
+			pr_warn("map '%s': failed to resize memory-mapped region: %s\n",
+				bpf_map__name(map), errstr(err));
+			return libbpf_err(err);
+		}
+		err = map_btf_datasec_resize(map, size);
+		if (err && err != -ENOENT) {
+			pr_warn("map '%s': failed to adjust resized BTF, clearing BTF key/value info: %s\n",
+				bpf_map__name(map), errstr(err));
+			map->btf_value_type_id = 0;
+			map->btf_key_type_id = 0;
+		}
+	}
+
+	map->def.value_size = size;
+	return 0;
+}
+
+__u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
+{
+	return map ? map->btf_key_type_id : 0;
+}
+
+__u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
+{
+	return map ? map->btf_value_type_id : 0;
+}
+
+int bpf_map__set_initial_value(struct bpf_map *map,
+			       const void *data, size_t size)
+{
+	size_t actual_sz;
+
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+
+	if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG)
+		return libbpf_err(-EINVAL);
+
+	if (map->def.type == BPF_MAP_TYPE_ARENA)
+		actual_sz = map->obj->arena_data_sz;
+	else
+		actual_sz = map->def.value_size;
+	if (size != actual_sz)
+		return libbpf_err(-EINVAL);
+
+	memcpy(map->mmaped, data, size);
+	return 0;
+}
+
+void *bpf_map__initial_value(const struct bpf_map *map, size_t *psize)
+{
+	if (bpf_map__is_struct_ops(map)) {
+		if (psize)
+			*psize = map->def.value_size;
+		return map->st_ops->data;
+	}
+
+	if (!map->mmaped)
+		return NULL;
+
+	if (map->def.type == BPF_MAP_TYPE_ARENA)
+		*psize = map->obj->arena_data_sz;
+	else
+		*psize = map->def.value_size;
+
+	return map->mmaped;
+}
+
+bool bpf_map__is_internal(const struct bpf_map *map)
+{
+	return map->libbpf_type != LIBBPF_MAP_UNSPEC;
+}
+
+__u32 bpf_map__ifindex(const struct bpf_map *map)
+{
+	return map->map_ifindex;
+}
+
+int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
+{
+	if (map_is_created(map))
+		return libbpf_err(-EBUSY);
+	map->map_ifindex = ifindex;
+	return 0;
+}
+
+int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
+{
+	if (!bpf_map_type__is_map_in_map(map->def.type)) {
+		pr_warn("error: unsupported map type\n");
+		return libbpf_err(-EINVAL);
+	}
+	if (map->inner_map_fd != -1) {
+		pr_warn("error: inner_map_fd already specified\n");
+		return libbpf_err(-EINVAL);
+	}
+	if (map->inner_map) {
+		bpf_map__destroy(map->inner_map);
+		zfree(&map->inner_map);
+	}
+	map->inner_map_fd = fd;
+	return 0;
+}
+
+int bpf_map__set_exclusive_program(struct bpf_map *map, struct bpf_program *prog)
+{
+	if (map_is_created(map)) {
+		pr_warn("exclusive programs must be set before map creation\n");
+		return libbpf_err(-EINVAL);
+	}
+
+	if (map->obj != prog->obj) {
+		pr_warn("excl_prog and map must be from the same bpf object\n");
+		return libbpf_err(-EINVAL);
+	}
+
+	map->excl_prog = prog;
+	return 0;
+}
+
+struct bpf_program *bpf_map__exclusive_program(struct bpf_map *map)
+{
+	return map->excl_prog;
+}
+
+static struct bpf_map *
+__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
+{
+	ssize_t idx;
+	struct bpf_map *s, *e;
+
+	if (!obj || !obj->maps)
+		return errno = EINVAL, NULL;
+
+	s = obj->maps;
+	e = obj->maps + obj->nr_maps;
+
+	if ((m < s) || (m >= e)) {
+		pr_warn("error in %s: map handler doesn't belong to object\n",
+			 __func__);
+		return errno = EINVAL, NULL;
+	}
+
+	idx = (m - obj->maps) + i;
+	if (idx >= obj->nr_maps || idx < 0)
+		return NULL;
+	return &obj->maps[idx];
+}
+
+struct bpf_map *
+bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev)
+{
+	if (prev == NULL && obj != NULL)
+		return obj->maps;
+
+	return __bpf_map__iter(prev, obj, 1);
+}
+
+struct bpf_map *
+bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *next)
+{
+	if (next == NULL && obj != NULL) {
+		if (!obj->nr_maps)
+			return NULL;
+		return obj->maps + obj->nr_maps - 1;
+	}
+
+	return __bpf_map__iter(next, obj, -1);
+}
+
+struct bpf_map *
+bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
+{
+	struct bpf_map *pos;
+
+	bpf_object__for_each_map(pos, obj) {
+		/* if it's a special internal map name (which always starts
+		 * with dot) then check if that special name matches the
+		 * real map name (ELF section name)
+		 */
+		if (name[0] == '.') {
+			if (pos->real_name && strcmp(pos->real_name, name) == 0)
+				return pos;
+			continue;
+		}
+		/* otherwise map name has to be an exact match */
+		if (map_uses_real_name(pos)) {
+			if (strcmp(pos->real_name, name) == 0)
+				return pos;
+			continue;
+		}
+		if (strcmp(pos->name, name) == 0)
+			return pos;
+	}
+	return errno = ENOENT, NULL;
+}
+
+int
+bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
+{
+	return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
+}
+
+static int validate_map_op(const struct bpf_map *map, size_t key_sz,
+			   size_t value_sz, bool check_value_sz, __u64 flags)
+{
+	if (!map_is_created(map)) /* map is not yet created */
+		return -ENOENT;
+
+	if (map->def.key_size != key_sz) {
+		pr_warn("map '%s': unexpected key size %zu provided, expected %u\n",
+			map->name, key_sz, map->def.key_size);
+		return -EINVAL;
+	}
+
+	if (map->fd < 0) {
+		pr_warn("map '%s': can't use BPF map without FD (was it created?)\n", map->name);
+		return -EINVAL;
+	}
+
+	if (!check_value_sz)
+		return 0;
+
+	switch (map->def.type) {
+	case BPF_MAP_TYPE_PERCPU_ARRAY:
+	case BPF_MAP_TYPE_PERCPU_HASH:
+	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: {
+		int num_cpu = libbpf_num_possible_cpus();
+		size_t elem_sz = roundup(map->def.value_size, 8);
+
+		if (flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) {
+			if ((flags & BPF_F_CPU) && (flags & BPF_F_ALL_CPUS)) {
+				pr_warn("map '%s': BPF_F_CPU and BPF_F_ALL_CPUS are mutually exclusive\n",
+					map->name);
+				return -EINVAL;
+			}
+			if (map->def.value_size != value_sz) {
+				pr_warn("map '%s': unexpected value size %zu provided for either BPF_F_CPU or BPF_F_ALL_CPUS, expected %u\n",
+					map->name, value_sz, map->def.value_size);
+				return -EINVAL;
+			}
+			break;
+		}
+
+		if (value_sz != num_cpu * elem_sz) {
+			pr_warn("map '%s': unexpected value size %zu provided for per-CPU map, expected %d * %zu = %zu\n",
+				map->name, value_sz, num_cpu, elem_sz, num_cpu * elem_sz);
+			return -EINVAL;
+		}
+		break;
+	}
+	default:
+		if (map->def.value_size != value_sz) {
+			pr_warn("map '%s': unexpected value size %zu provided, expected %u\n",
+				map->name, value_sz, map->def.value_size);
+			return -EINVAL;
+		}
+		break;
+	}
+	return 0;
+}
+
+int bpf_map__lookup_elem(const struct bpf_map *map,
+			 const void *key, size_t key_sz,
+			 void *value, size_t value_sz, __u64 flags)
+{
+	int err;
+
+	err = validate_map_op(map, key_sz, value_sz, true, flags);
+	if (err)
+		return libbpf_err(err);
+
+	return bpf_map_lookup_elem_flags(map->fd, key, value, flags);
+}
+
+int bpf_map__update_elem(const struct bpf_map *map,
+			 const void *key, size_t key_sz,
+			 const void *value, size_t value_sz, __u64 flags)
+{
+	int err;
+
+	err = validate_map_op(map, key_sz, value_sz, true, flags);
+	if (err)
+		return libbpf_err(err);
+
+	return bpf_map_update_elem(map->fd, key, value, flags);
+}
+
+int bpf_map__delete_elem(const struct bpf_map *map,
+			 const void *key, size_t key_sz, __u64 flags)
+{
+	int err;
+
+	err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, flags);
+	if (err)
+		return libbpf_err(err);
+
+	return bpf_map_delete_elem_flags(map->fd, key, flags);
+}
+
+int bpf_map__lookup_and_delete_elem(const struct bpf_map *map,
+				    const void *key, size_t key_sz,
+				    void *value, size_t value_sz, __u64 flags)
+{
+	int err;
+
+	err = validate_map_op(map, key_sz, value_sz, true, flags);
+	if (err)
+		return libbpf_err(err);
+
+	return bpf_map_lookup_and_delete_elem_flags(map->fd, key, value, flags);
+}
+
+int bpf_map__get_next_key(const struct bpf_map *map,
+			  const void *cur_key, void *next_key, size_t key_sz)
+{
+	int err;
+
+	err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, 0);
+	if (err)
+		return libbpf_err(err);
+
+	return bpf_map_get_next_key(map->fd, cur_key, next_key);
+}
+
+long libbpf_get_error(const void *ptr)
+{
+	if (!IS_ERR_OR_NULL(ptr))
+		return 0;
+
+	if (IS_ERR(ptr))
+		errno = -PTR_ERR(ptr);
+
+	/* If ptr == NULL, then errno should be already set by the failing
+	 * API, because libbpf never returns NULL on success and it now always
+	 * sets errno on error. So no extra errno handling for ptr == NULL
+	 * case.
+	 */
+	return -errno;
+}
+
+/* Replace link's underlying BPF program with the new one */
+int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog)
+{
+	int ret;
+	int prog_fd = bpf_program__fd(prog);
+
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't use BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	ret = bpf_link_update(bpf_link__fd(link), prog_fd, NULL);
+	return libbpf_err_errno(ret);
+}
+
+/* Release "ownership" of underlying BPF resource (typically, BPF program
+ * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected
+ * link, when destructed through bpf_link__destroy() call won't attempt to
+ * detach/unregisted that BPF resource. This is useful in situations where,
+ * say, attached BPF program has to outlive userspace program that attached it
+ * in the system. Depending on type of BPF program, though, there might be
+ * additional steps (like pinning BPF program in BPF FS) necessary to ensure
+ * exit of userspace program doesn't trigger automatic detachment and clean up
+ * inside the kernel.
+ */
+void bpf_link__disconnect(struct bpf_link *link)
+{
+	link->disconnected = true;
+}
+
+int bpf_link__destroy(struct bpf_link *link)
+{
+	int err = 0;
+
+	if (IS_ERR_OR_NULL(link))
+		return 0;
+
+	if (!link->disconnected && link->detach)
+		err = link->detach(link);
+	if (link->pin_path)
+		free(link->pin_path);
+	if (link->dealloc)
+		link->dealloc(link);
+	else
+		free(link);
+
+	return libbpf_err(err);
+}
+
+int bpf_link__fd(const struct bpf_link *link)
+{
+	return link->fd;
+}
+
+const char *bpf_link__pin_path(const struct bpf_link *link)
+{
+	return link->pin_path;
+}
+
+static int bpf_link__detach_fd(struct bpf_link *link)
+{
+	return libbpf_err_errno(close(link->fd));
+}
+
+struct bpf_link *bpf_link__open(const char *path)
+{
+	struct bpf_link *link;
+	int fd;
+
+	fd = bpf_obj_get(path);
+	if (fd < 0) {
+		fd = -errno;
+		pr_warn("failed to open link at %s: %d\n", path, fd);
+		return libbpf_err_ptr(fd);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link) {
+		close(fd);
+		return libbpf_err_ptr(-ENOMEM);
+	}
+	link->detach = &bpf_link__detach_fd;
+	link->fd = fd;
+
+	link->pin_path = strdup(path);
+	if (!link->pin_path) {
+		bpf_link__destroy(link);
+		return libbpf_err_ptr(-ENOMEM);
+	}
+
+	return link;
+}
+
+int bpf_link__detach(struct bpf_link *link)
+{
+	return bpf_link_detach(link->fd) ? -errno : 0;
+}
+
+int bpf_link__pin(struct bpf_link *link, const char *path)
+{
+	int err;
+
+	if (link->pin_path)
+		return libbpf_err(-EBUSY);
+	err = make_parent_dir(path);
+	if (err)
+		return libbpf_err(err);
+	err = check_path(path);
+	if (err)
+		return libbpf_err(err);
+
+	link->pin_path = strdup(path);
+	if (!link->pin_path)
+		return libbpf_err(-ENOMEM);
+
+	if (bpf_obj_pin(link->fd, link->pin_path)) {
+		err = -errno;
+		zfree(&link->pin_path);
+		return libbpf_err(err);
+	}
+
+	pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path);
+	return 0;
+}
+
+int bpf_link__unpin(struct bpf_link *link)
+{
+	int err;
+
+	if (!link->pin_path)
+		return libbpf_err(-EINVAL);
+
+	err = unlink(link->pin_path);
+	if (err != 0)
+		return -errno;
+
+	pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path);
+	zfree(&link->pin_path);
+	return 0;
+}
+
+struct bpf_link_perf {
+	struct bpf_link link;
+	int perf_event_fd;
+	/* legacy kprobe support: keep track of probe identifier and type */
+	char *legacy_probe_name;
+	bool legacy_is_kprobe;
+	bool legacy_is_retprobe;
+};
+
+static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe);
+static int remove_uprobe_event_legacy(const char *probe_name, bool retprobe);
+
+static int bpf_link_perf_detach(struct bpf_link *link)
+{
+	struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
+	int err = 0;
+
+	if (ioctl(perf_link->perf_event_fd, PERF_EVENT_IOC_DISABLE, 0) < 0)
+		err = -errno;
+
+	if (perf_link->perf_event_fd != link->fd)
+		close(perf_link->perf_event_fd);
+	close(link->fd);
+
+	/* legacy uprobe/kprobe needs to be removed after perf event fd closure */
+	if (perf_link->legacy_probe_name) {
+		if (perf_link->legacy_is_kprobe) {
+			err = remove_kprobe_event_legacy(perf_link->legacy_probe_name,
+							 perf_link->legacy_is_retprobe);
+		} else {
+			err = remove_uprobe_event_legacy(perf_link->legacy_probe_name,
+							 perf_link->legacy_is_retprobe);
+		}
+	}
+
+	return err;
+}
+
+static void bpf_link_perf_dealloc(struct bpf_link *link)
+{
+	struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
+
+	free(perf_link->legacy_probe_name);
+	free(perf_link);
+}
+
+struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd,
+						     const struct bpf_perf_event_opts *opts)
+{
+	struct bpf_link_perf *link;
+	int prog_fd, link_fd = -1, err;
+	bool force_ioctl_attach;
+
+	if (!OPTS_VALID(opts, bpf_perf_event_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	if (pfd < 0) {
+		pr_warn("prog '%s': invalid perf event FD %d\n",
+			prog->name, pfd);
+		return libbpf_err_ptr(-EINVAL);
+	}
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+	link->link.detach = &bpf_link_perf_detach;
+	link->link.dealloc = &bpf_link_perf_dealloc;
+	link->perf_event_fd = pfd;
+
+	force_ioctl_attach = OPTS_GET(opts, force_ioctl_attach, false);
+	if (kernel_supports(prog->obj, FEAT_PERF_LINK) && !force_ioctl_attach) {
+		DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_opts,
+			.perf_event.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0));
+
+		link_fd = bpf_link_create(prog_fd, pfd, BPF_PERF_EVENT, &link_opts);
+		if (link_fd < 0) {
+			err = -errno;
+			pr_warn("prog '%s': failed to create BPF link for perf_event FD %d: %s\n",
+				prog->name, pfd, errstr(err));
+			goto err_out;
+		}
+		link->link.fd = link_fd;
+	} else {
+		if (OPTS_GET(opts, bpf_cookie, 0)) {
+			pr_warn("prog '%s': user context value is not supported\n", prog->name);
+			err = -EOPNOTSUPP;
+			goto err_out;
+		}
+
+		if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
+			err = -errno;
+			pr_warn("prog '%s': failed to attach to perf_event FD %d: %s\n",
+				prog->name, pfd, errstr(err));
+			if (err == -EPROTO)
+				pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n",
+					prog->name, pfd);
+			goto err_out;
+		}
+		link->link.fd = pfd;
+	}
+
+	if (!OPTS_GET(opts, dont_enable, false)) {
+		if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
+			err = -errno;
+			pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n",
+				prog->name, pfd, errstr(err));
+			goto err_out;
+		}
+	}
+
+	return &link->link;
+err_out:
+	if (link_fd >= 0)
+		close(link_fd);
+	free(link);
+	return libbpf_err_ptr(err);
+}
+
+struct bpf_link *bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd)
+{
+	return bpf_program__attach_perf_event_opts(prog, pfd, NULL);
+}
+
+/*
+ * this function is expected to parse integer in the range of [0, 2^31-1] from
+ * given file using scanf format string fmt. If actual parsed value is
+ * negative, the result might be indistinguishable from error
+ */
+static int parse_uint_from_file(const char *file, const char *fmt)
+{
+	int err, ret;
+	FILE *f;
+
+	f = fopen(file, "re");
+	if (!f) {
+		err = -errno;
+		pr_debug("failed to open '%s': %s\n", file, errstr(err));
+		return err;
+	}
+	err = fscanf(f, fmt, &ret);
+	if (err != 1) {
+		err = err == EOF ? -EIO : -errno;
+		pr_debug("failed to parse '%s': %s\n", file, errstr(err));
+		fclose(f);
+		return err;
+	}
+	fclose(f);
+	return ret;
+}
+
+static int determine_kprobe_perf_type(void)
+{
+	const char *file = "/sys/bus/event_source/devices/kprobe/type";
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int determine_uprobe_perf_type(void)
+{
+	const char *file = "/sys/bus/event_source/devices/uprobe/type";
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int determine_kprobe_retprobe_bit(void)
+{
+	const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
+
+	return parse_uint_from_file(file, "config:%d\n");
+}
+
+static int determine_uprobe_retprobe_bit(void)
+{
+	const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
+
+	return parse_uint_from_file(file, "config:%d\n");
+}
+
+#define PERF_UPROBE_REF_CTR_OFFSET_BITS 32
+#define PERF_UPROBE_REF_CTR_OFFSET_SHIFT 32
+
+static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
+				 uint64_t offset, int pid, size_t ref_ctr_off)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	struct perf_event_attr attr;
+	int type, pfd;
+
+	if ((__u64)ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS))
+		return -EINVAL;
+
+	memset(&attr, 0, attr_sz);
+
+	type = uprobe ? determine_uprobe_perf_type()
+		      : determine_kprobe_perf_type();
+	if (type < 0) {
+		pr_warn("failed to determine %s perf type: %s\n",
+			uprobe ? "uprobe" : "kprobe",
+			errstr(type));
+		return type;
+	}
+	if (retprobe) {
+		int bit = uprobe ? determine_uprobe_retprobe_bit()
+				 : determine_kprobe_retprobe_bit();
+
+		if (bit < 0) {
+			pr_warn("failed to determine %s retprobe bit: %s\n",
+				uprobe ? "uprobe" : "kprobe",
+				errstr(bit));
+			return bit;
+		}
+		attr.config |= 1 << bit;
+	}
+	attr.size = attr_sz;
+	attr.type = type;
+	attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
+	attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
+	attr.config2 = offset;		 /* kprobe_addr or probe_offset */
+
+	/* pid filter is meaningful only for uprobes */
+	pfd = syscall(__NR_perf_event_open, &attr,
+		      pid < 0 ? -1 : pid /* pid */,
+		      pid == -1 ? 0 : -1 /* cpu */,
+		      -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
+	return pfd >= 0 ? pfd : -errno;
+}
+
+static int append_to_file(const char *file, const char *fmt, ...)
+{
+	int fd, n, err = 0;
+	va_list ap;
+	char buf[1024];
+
+	va_start(ap, fmt);
+	n = vsnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+
+	if (n < 0 || n >= sizeof(buf))
+		return -EINVAL;
+
+	fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0);
+	if (fd < 0)
+		return -errno;
+
+	if (write(fd, buf, n) < 0)
+		err = -errno;
+
+	close(fd);
+	return err;
+}
+
+#define DEBUGFS "/sys/kernel/debug/tracing"
+#define TRACEFS "/sys/kernel/tracing"
+
+static bool use_debugfs(void)
+{
+	static int has_debugfs = -1;
+
+	if (has_debugfs < 0)
+		has_debugfs = faccessat(AT_FDCWD, DEBUGFS, F_OK, AT_EACCESS) == 0;
+
+	return has_debugfs == 1;
+}
+
+static const char *tracefs_path(void)
+{
+	return use_debugfs() ? DEBUGFS : TRACEFS;
+}
+
+static const char *tracefs_kprobe_events(void)
+{
+	return use_debugfs() ? DEBUGFS"/kprobe_events" : TRACEFS"/kprobe_events";
+}
+
+static const char *tracefs_uprobe_events(void)
+{
+	return use_debugfs() ? DEBUGFS"/uprobe_events" : TRACEFS"/uprobe_events";
+}
+
+static const char *tracefs_available_filter_functions(void)
+{
+	return use_debugfs() ? DEBUGFS"/available_filter_functions"
+			     : TRACEFS"/available_filter_functions";
+}
+
+static const char *tracefs_available_filter_functions_addrs(void)
+{
+	return use_debugfs() ? DEBUGFS"/available_filter_functions_addrs"
+			     : TRACEFS"/available_filter_functions_addrs";
+}
+
+static void gen_probe_legacy_event_name(char *buf, size_t buf_sz,
+					const char *name, size_t offset)
+{
+	static int index = 0;
+	int i;
+
+	snprintf(buf, buf_sz, "libbpf_%d_%d_%s_0x%zx", getpid(),
+		 __sync_fetch_and_add(&index, 1), name, offset);
+
+	/* sanitize name in the probe name */
+	for (i = 0; buf[i]; i++) {
+		if (!isalnum(buf[i]))
+			buf[i] = '_';
+	}
+}
+
+static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,
+				   const char *kfunc_name, size_t offset)
+{
+	return append_to_file(tracefs_kprobe_events(), "%c:%s/%s %s+0x%zx",
+			      retprobe ? 'r' : 'p',
+			      retprobe ? "kretprobes" : "kprobes",
+			      probe_name, kfunc_name, offset);
+}
+
+static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe)
+{
+	return append_to_file(tracefs_kprobe_events(), "-:%s/%s",
+			      retprobe ? "kretprobes" : "kprobes", probe_name);
+}
+
+static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retprobe)
+{
+	char file[256];
+
+	snprintf(file, sizeof(file), "%s/events/%s/%s/id",
+		 tracefs_path(), retprobe ? "kretprobes" : "kprobes", probe_name);
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
+					 const char *kfunc_name, size_t offset, int pid)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	struct perf_event_attr attr;
+	int type, pfd, err;
+
+	err = add_kprobe_event_legacy(probe_name, retprobe, kfunc_name, offset);
+	if (err < 0) {
+		pr_warn("failed to add legacy kprobe event for '%s+0x%zx': %s\n",
+			kfunc_name, offset,
+			errstr(err));
+		return err;
+	}
+	type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
+	if (type < 0) {
+		err = type;
+		pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
+			kfunc_name, offset,
+			errstr(err));
+		goto err_clean_legacy;
+	}
+
+	memset(&attr, 0, attr_sz);
+	attr.size = attr_sz;
+	attr.config = type;
+	attr.type = PERF_TYPE_TRACEPOINT;
+
+	pfd = syscall(__NR_perf_event_open, &attr,
+		      pid < 0 ? -1 : pid, /* pid */
+		      pid == -1 ? 0 : -1, /* cpu */
+		      -1 /* group_fd */,  PERF_FLAG_FD_CLOEXEC);
+	if (pfd < 0) {
+		err = -errno;
+		pr_warn("legacy kprobe perf_event_open() failed: %s\n",
+			errstr(err));
+		goto err_clean_legacy;
+	}
+	return pfd;
+
+err_clean_legacy:
+	/* Clear the newly added legacy kprobe_event */
+	remove_kprobe_event_legacy(probe_name, retprobe);
+	return err;
+}
+
+static const char *arch_specific_syscall_pfx(void)
+{
+#if defined(__x86_64__)
+	return "x64";
+#elif defined(__i386__)
+	return "ia32";
+#elif defined(__s390x__)
+	return "s390x";
+#elif defined(__arm__)
+	return "arm";
+#elif defined(__aarch64__)
+	return "arm64";
+#elif defined(__mips__)
+	return "mips";
+#elif defined(__riscv)
+	return "riscv";
+#elif defined(__powerpc__)
+	return "powerpc";
+#elif defined(__powerpc64__)
+	return "powerpc64";
+#else
+	return NULL;
+#endif
+}
+
+int probe_kern_syscall_wrapper(int token_fd)
+{
+	char syscall_name[64];
+	const char *ksys_pfx;
+
+	ksys_pfx = arch_specific_syscall_pfx();
+	if (!ksys_pfx)
+		return 0;
+
+	snprintf(syscall_name, sizeof(syscall_name), "__%s_sys_bpf", ksys_pfx);
+
+	if (determine_kprobe_perf_type() >= 0) {
+		int pfd;
+
+		pfd = perf_event_open_probe(false, false, syscall_name, 0, getpid(), 0);
+		if (pfd >= 0)
+			close(pfd);
+
+		return pfd >= 0 ? 1 : 0;
+	} else { /* legacy mode */
+		char probe_name[MAX_EVENT_NAME_LEN];
+
+		gen_probe_legacy_event_name(probe_name, sizeof(probe_name), syscall_name, 0);
+		if (add_kprobe_event_legacy(probe_name, false, syscall_name, 0) < 0)
+			return 0;
+
+		(void)remove_kprobe_event_legacy(probe_name, false);
+		return 1;
+	}
+}
+
+struct bpf_link *
+bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
+				const char *func_name,
+				const struct bpf_kprobe_opts *opts)
+{
+	DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
+	enum probe_attach_mode attach_mode;
+	char *legacy_probe = NULL;
+	struct bpf_link *link;
+	size_t offset;
+	bool retprobe, legacy;
+	int pfd, err;
+
+	if (!OPTS_VALID(opts, bpf_kprobe_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT);
+	retprobe = OPTS_GET(opts, retprobe, false);
+	offset = OPTS_GET(opts, offset, 0);
+	pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+
+	legacy = determine_kprobe_perf_type() < 0;
+	switch (attach_mode) {
+	case PROBE_ATTACH_MODE_LEGACY:
+		legacy = true;
+		pe_opts.force_ioctl_attach = true;
+		break;
+	case PROBE_ATTACH_MODE_PERF:
+		if (legacy)
+			return libbpf_err_ptr(-ENOTSUP);
+		pe_opts.force_ioctl_attach = true;
+		break;
+	case PROBE_ATTACH_MODE_LINK:
+		if (legacy || !kernel_supports(prog->obj, FEAT_PERF_LINK))
+			return libbpf_err_ptr(-ENOTSUP);
+		break;
+	case PROBE_ATTACH_MODE_DEFAULT:
+		break;
+	default:
+		return libbpf_err_ptr(-EINVAL);
+	}
+	if (!func_name && legacy)
+		return libbpf_err_ptr(-EOPNOTSUPP);
+
+	if (!legacy) {
+		pfd = perf_event_open_probe(false /* uprobe */, retprobe,
+					    func_name, offset,
+					    -1 /* pid */, 0 /* ref_ctr_off */);
+	} else {
+		char probe_name[MAX_EVENT_NAME_LEN];
+
+		gen_probe_legacy_event_name(probe_name, sizeof(probe_name),
+					    func_name, offset);
+
+		legacy_probe = strdup(probe_name);
+		if (!legacy_probe)
+			return libbpf_err_ptr(-ENOMEM);
+
+		pfd = perf_event_kprobe_open_legacy(legacy_probe, retprobe, func_name,
+						    offset, -1 /* pid */);
+	}
+	if (pfd < 0) {
+		err = pfd;
+		pr_warn("prog '%s': failed to create %s '%s%s0x%zx' perf event: %s\n",
+			prog->name, retprobe ? "kretprobe" : "kprobe",
+			func_name ?: "", func_name ? "+" : "",
+			offset, errstr(err));
+		goto err_out;
+	}
+	link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
+	err = libbpf_get_error(link);
+	if (err) {
+		close(pfd);
+		pr_warn("prog '%s': failed to attach to %s '%s%s0x%zx': %s\n",
+			prog->name, retprobe ? "kretprobe" : "kprobe",
+			func_name ?: "", func_name ? "+" : "",
+			offset, errstr(err));
+		goto err_clean_legacy;
+	}
+	if (legacy) {
+		struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
+
+		perf_link->legacy_probe_name = legacy_probe;
+		perf_link->legacy_is_kprobe = true;
+		perf_link->legacy_is_retprobe = retprobe;
+	}
+
+	return link;
+
+err_clean_legacy:
+	if (legacy)
+		remove_kprobe_event_legacy(legacy_probe, retprobe);
+err_out:
+	free(legacy_probe);
+	return libbpf_err_ptr(err);
+}
+
+struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog,
+					    bool retprobe,
+					    const char *func_name)
+{
+	DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts,
+		.retprobe = retprobe,
+	);
+
+	return bpf_program__attach_kprobe_opts(prog, func_name, &opts);
+}
+
+struct bpf_link *bpf_program__attach_ksyscall(const struct bpf_program *prog,
+					      const char *syscall_name,
+					      const struct bpf_ksyscall_opts *opts)
+{
+	LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts);
+	char func_name[128];
+
+	if (!OPTS_VALID(opts, bpf_ksyscall_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	if (kernel_supports(prog->obj, FEAT_SYSCALL_WRAPPER)) {
+		/* arch_specific_syscall_pfx() should never return NULL here
+		 * because it is guarded by kernel_supports(). However, since
+		 * compiler does not know that we have an explicit conditional
+		 * as well.
+		 */
+		snprintf(func_name, sizeof(func_name), "__%s_sys_%s",
+			 arch_specific_syscall_pfx() ? : "", syscall_name);
+	} else {
+		snprintf(func_name, sizeof(func_name), "__se_sys_%s", syscall_name);
+	}
+
+	kprobe_opts.retprobe = OPTS_GET(opts, retprobe, false);
+	kprobe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+
+	return bpf_program__attach_kprobe_opts(prog, func_name, &kprobe_opts);
+}
+
+/* Adapted from perf/util/string.c */
+bool glob_match(const char *str, const char *pat)
+{
+	while (*str && *pat && *pat != '*') {
+		if (*pat == '?') {      /* Matches any single character */
+			str++;
+			pat++;
+			continue;
+		}
+		if (*str != *pat)
+			return false;
+		str++;
+		pat++;
+	}
+	/* Check wild card */
+	if (*pat == '*') {
+		while (*pat == '*')
+			pat++;
+		if (!*pat) /* Tail wild card matches all */
+			return true;
+		while (*str)
+			if (glob_match(str++, pat))
+				return true;
+	}
+	return !*str && !*pat;
+}
+
+struct kprobe_multi_resolve {
+	const char *pattern;
+	unsigned long *addrs;
+	size_t cap;
+	size_t cnt;
+};
+
+struct avail_kallsyms_data {
+	char **syms;
+	size_t cnt;
+	struct kprobe_multi_resolve *res;
+};
+
+static int avail_func_cmp(const void *a, const void *b)
+{
+	return strcmp(*(const char **)a, *(const char **)b);
+}
+
+static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type,
+			     const char *sym_name, void *ctx)
+{
+	struct avail_kallsyms_data *data = ctx;
+	struct kprobe_multi_resolve *res = data->res;
+	int err;
+
+	if (!glob_match(sym_name, res->pattern))
+		return 0;
+
+	if (!bsearch(&sym_name, data->syms, data->cnt, sizeof(*data->syms), avail_func_cmp)) {
+		/* Some versions of kernel strip out .llvm.<hash> suffix from
+		 * function names reported in available_filter_functions, but
+		 * don't do so for kallsyms. While this is clearly a kernel
+		 * bug (fixed by [0]) we try to accommodate that in libbpf to
+		 * make multi-kprobe usability a bit better: if no match is
+		 * found, we will strip .llvm. suffix and try one more time.
+		 *
+		 *   [0] fb6a421fb615 ("kallsyms: Match symbols exactly with CONFIG_LTO_CLANG")
+		 */
+		char sym_trim[256], *psym_trim = sym_trim;
+		const char *sym_sfx;
+
+		if (!(sym_sfx = strstr(sym_name, ".llvm.")))
+			return 0;
+
+		/* psym_trim vs sym_trim dance is done to avoid pointer vs array
+		 * coercion differences and get proper `const char **` pointer
+		 * which avail_func_cmp() expects
+		 */
+		snprintf(sym_trim, sizeof(sym_trim), "%.*s", (int)(sym_sfx - sym_name), sym_name);
+		if (!bsearch(&psym_trim, data->syms, data->cnt, sizeof(*data->syms), avail_func_cmp))
+			return 0;
+	}
+
+	err = libbpf_ensure_mem((void **)&res->addrs, &res->cap, sizeof(*res->addrs), res->cnt + 1);
+	if (err)
+		return err;
+
+	res->addrs[res->cnt++] = (unsigned long)sym_addr;
+	return 0;
+}
+
+static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res)
+{
+	const char *available_functions_file = tracefs_available_filter_functions();
+	struct avail_kallsyms_data data;
+	char sym_name[500];
+	FILE *f;
+	int err = 0, ret, i;
+	char **syms = NULL;
+	size_t cap = 0, cnt = 0;
+
+	f = fopen(available_functions_file, "re");
+	if (!f) {
+		err = -errno;
+		pr_warn("failed to open %s: %s\n", available_functions_file, errstr(err));
+		return err;
+	}
+
+	while (true) {
+		char *name;
+
+		ret = fscanf(f, "%499s%*[^\n]\n", sym_name);
+		if (ret == EOF && feof(f))
+			break;
+
+		if (ret != 1) {
+			pr_warn("failed to parse available_filter_functions entry: %d\n", ret);
+			err = -EINVAL;
+			goto cleanup;
+		}
+
+		if (!glob_match(sym_name, res->pattern))
+			continue;
+
+		err = libbpf_ensure_mem((void **)&syms, &cap, sizeof(*syms), cnt + 1);
+		if (err)
+			goto cleanup;
+
+		name = strdup(sym_name);
+		if (!name) {
+			err = -errno;
+			goto cleanup;
+		}
+
+		syms[cnt++] = name;
+	}
+
+	/* no entries found, bail out */
+	if (cnt == 0) {
+		err = -ENOENT;
+		goto cleanup;
+	}
+
+	/* sort available functions */
+	qsort(syms, cnt, sizeof(*syms), avail_func_cmp);
+
+	data.syms = syms;
+	data.res = res;
+	data.cnt = cnt;
+	libbpf_kallsyms_parse(avail_kallsyms_cb, &data);
+
+	if (res->cnt == 0)
+		err = -ENOENT;
+
+cleanup:
+	for (i = 0; i < cnt; i++)
+		free((char *)syms[i]);
+	free(syms);
+
+	fclose(f);
+	return err;
+}
+
+static bool has_available_filter_functions_addrs(void)
+{
+	return access(tracefs_available_filter_functions_addrs(), R_OK) != -1;
+}
+
+static int libbpf_available_kprobes_parse(struct kprobe_multi_resolve *res)
+{
+	const char *available_path = tracefs_available_filter_functions_addrs();
+	char sym_name[500];
+	FILE *f;
+	int ret, err = 0;
+	unsigned long long sym_addr;
+
+	f = fopen(available_path, "re");
+	if (!f) {
+		err = -errno;
+		pr_warn("failed to open %s: %s\n", available_path, errstr(err));
+		return err;
+	}
+
+	while (true) {
+		ret = fscanf(f, "%llx %499s%*[^\n]\n", &sym_addr, sym_name);
+		if (ret == EOF && feof(f))
+			break;
+
+		if (ret != 2) {
+			pr_warn("failed to parse available_filter_functions_addrs entry: %d\n",
+				ret);
+			err = -EINVAL;
+			goto cleanup;
+		}
+
+		if (!glob_match(sym_name, res->pattern))
+			continue;
+
+		err = libbpf_ensure_mem((void **)&res->addrs, &res->cap,
+					sizeof(*res->addrs), res->cnt + 1);
+		if (err)
+			goto cleanup;
+
+		res->addrs[res->cnt++] = (unsigned long)sym_addr;
+	}
+
+	if (res->cnt == 0)
+		err = -ENOENT;
+
+cleanup:
+	fclose(f);
+	return err;
+}
+
+struct bpf_link *
+bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
+				      const char *pattern,
+				      const struct bpf_kprobe_multi_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, lopts);
+	struct kprobe_multi_resolve res = {
+		.pattern = pattern,
+	};
+	enum bpf_attach_type attach_type;
+	struct bpf_link *link = NULL;
+	const unsigned long *addrs;
+	int err, link_fd, prog_fd;
+	bool retprobe, session, unique_match;
+	const __u64 *cookies;
+	const char **syms;
+	size_t cnt;
+
+	if (!OPTS_VALID(opts, bpf_kprobe_multi_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	syms    = OPTS_GET(opts, syms, false);
+	addrs   = OPTS_GET(opts, addrs, false);
+	cnt     = OPTS_GET(opts, cnt, false);
+	cookies = OPTS_GET(opts, cookies, false);
+	unique_match = OPTS_GET(opts, unique_match, false);
+
+	if (!pattern && !addrs && !syms)
+		return libbpf_err_ptr(-EINVAL);
+	if (pattern && (addrs || syms || cookies || cnt))
+		return libbpf_err_ptr(-EINVAL);
+	if (!pattern && !cnt)
+		return libbpf_err_ptr(-EINVAL);
+	if (!pattern && unique_match)
+		return libbpf_err_ptr(-EINVAL);
+	if (addrs && syms)
+		return libbpf_err_ptr(-EINVAL);
+
+	/*
+	 * Exact function name (no wildcards) without unique_match:
+	 * bypass kallsyms parsing and pass the symbol directly to the
+	 * kernel via syms[] array.  When unique_match is set, fall
+	 * through to the slow path which detects duplicate symbols.
+	 */
+	if (pattern && !strpbrk(pattern, "*?") && !unique_match) {
+		syms = &pattern;
+		cnt = 1;
+	} else if (pattern) {
+		if (has_available_filter_functions_addrs())
+			err = libbpf_available_kprobes_parse(&res);
+		else
+			err = libbpf_available_kallsyms_parse(&res);
+		if (err)
+			goto error;
+
+		if (unique_match && res.cnt != 1) {
+			pr_warn("prog '%s': failed to find a unique match for '%s' (%zu matches)\n",
+				prog->name, pattern, res.cnt);
+			err = -EINVAL;
+			goto error;
+		}
+
+		addrs = res.addrs;
+		cnt = res.cnt;
+	}
+
+	retprobe = OPTS_GET(opts, retprobe, false);
+	session  = OPTS_GET(opts, session, false);
+
+	if (retprobe && session)
+		return libbpf_err_ptr(-EINVAL);
+
+	attach_type = session ? BPF_TRACE_KPROBE_SESSION : BPF_TRACE_KPROBE_MULTI;
+
+	lopts.kprobe_multi.syms = syms;
+	lopts.kprobe_multi.addrs = addrs;
+	lopts.kprobe_multi.cookies = cookies;
+	lopts.kprobe_multi.cnt = cnt;
+	lopts.kprobe_multi.flags = retprobe ? BPF_F_KPROBE_MULTI_RETURN : 0;
+
+	link = calloc(1, sizeof(*link));
+	if (!link) {
+		err = -ENOMEM;
+		goto error;
+	}
+	link->detach = &bpf_link__detach_fd;
+
+	link_fd = bpf_link_create(prog_fd, 0, attach_type, &lopts);
+	if (link_fd < 0) {
+		err = -errno;
+		/*
+		 * Normalize error code: when exact name bypasses kallsyms
+		 * parsing, kernel returns ESRCH from ftrace_lookup_symbols().
+		 * Convert to ENOENT for API consistency with the pattern
+		 * matching path which returns ENOENT from userspace.
+		 */
+		if (err == -ESRCH)
+			err = -ENOENT;
+		pr_warn("prog '%s': failed to attach: %s\n",
+			prog->name, errstr(err));
+		goto error;
+	}
+	link->fd = link_fd;
+	free(res.addrs);
+	return link;
+
+error:
+	free(link);
+	free(res.addrs);
+	return libbpf_err_ptr(err);
+}
+
+static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts);
+	long offset = 0;
+	const char *func_name;
+	char *func;
+	int n;
+
+	*link = NULL;
+
+	/* no auto-attach for SEC("kprobe") and SEC("kretprobe") */
+	if (strcmp(prog->sec_name, "kprobe") == 0 || strcmp(prog->sec_name, "kretprobe") == 0)
+		return 0;
+
+	opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe/");
+	if (opts.retprobe)
+		func_name = prog->sec_name + sizeof("kretprobe/") - 1;
+	else
+		func_name = prog->sec_name + sizeof("kprobe/") - 1;
+
+	n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset);
+	if (n < 1) {
+		pr_warn("kprobe name is invalid: %s\n", func_name);
+		return -EINVAL;
+	}
+
+	if (offset < 0) {
+		free(func);
+		pr_warn("kprobe offset must be a non-negative integer: %li\n", offset);
+		return -EINVAL;
+	}
+
+	if (opts.retprobe && offset != 0) {
+		free(func);
+		pr_warn("kretprobes do not support offset specification\n");
+		return -EINVAL;
+	}
+
+	opts.offset = offset;
+	*link = bpf_program__attach_kprobe_opts(prog, func, &opts);
+	free(func);
+	return libbpf_get_error(*link);
+}
+
+static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	LIBBPF_OPTS(bpf_ksyscall_opts, opts);
+	const char *syscall_name;
+
+	*link = NULL;
+
+	/* no auto-attach for SEC("ksyscall") and SEC("kretsyscall") */
+	if (strcmp(prog->sec_name, "ksyscall") == 0 || strcmp(prog->sec_name, "kretsyscall") == 0)
+		return 0;
+
+	opts.retprobe = str_has_pfx(prog->sec_name, "kretsyscall/");
+	if (opts.retprobe)
+		syscall_name = prog->sec_name + sizeof("kretsyscall/") - 1;
+	else
+		syscall_name = prog->sec_name + sizeof("ksyscall/") - 1;
+
+	*link = bpf_program__attach_ksyscall(prog, syscall_name, &opts);
+	return *link ? 0 : -errno;
+}
+
+static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+	const char *spec;
+	char *pattern;
+	int n;
+
+	*link = NULL;
+
+	/* no auto-attach for SEC("kprobe.multi") and SEC("kretprobe.multi") */
+	if (strcmp(prog->sec_name, "kprobe.multi") == 0 ||
+	    strcmp(prog->sec_name, "kretprobe.multi") == 0)
+		return 0;
+
+	opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe.multi/");
+	if (opts.retprobe)
+		spec = prog->sec_name + sizeof("kretprobe.multi/") - 1;
+	else
+		spec = prog->sec_name + sizeof("kprobe.multi/") - 1;
+
+	n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
+	if (n < 1) {
+		pr_warn("kprobe multi pattern is invalid: %s\n", spec);
+		return -EINVAL;
+	}
+
+	*link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts);
+	free(pattern);
+	return libbpf_get_error(*link);
+}
+
+static int attach_kprobe_session(const struct bpf_program *prog, long cookie,
+				 struct bpf_link **link)
+{
+	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts, .session = true);
+	const char *spec;
+	char *pattern;
+	int n;
+
+	*link = NULL;
+
+	/* no auto-attach for SEC("kprobe.session") */
+	if (strcmp(prog->sec_name, "kprobe.session") == 0)
+		return 0;
+
+	spec = prog->sec_name + sizeof("kprobe.session/") - 1;
+	n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
+	if (n < 1) {
+		pr_warn("kprobe session pattern is invalid: %s\n", spec);
+		return -EINVAL;
+	}
+
+	*link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts);
+	free(pattern);
+	return *link ? 0 : -errno;
+}
+
+static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	char *probe_type = NULL, *binary_path = NULL, *func_name = NULL;
+	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
+	int n, ret = -EINVAL;
+
+	*link = NULL;
+
+	n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[^\n]",
+		   &probe_type, &binary_path, &func_name);
+	switch (n) {
+	case 1:
+		/* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */
+		ret = 0;
+		break;
+	case 3:
+		opts.session = str_has_pfx(probe_type, "uprobe.session");
+		opts.retprobe = str_has_pfx(probe_type, "uretprobe.multi");
+
+		*link = bpf_program__attach_uprobe_multi(prog, -1, binary_path, func_name, &opts);
+		ret = libbpf_get_error(*link);
+		break;
+	default:
+		pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name,
+			prog->sec_name);
+		break;
+	}
+	free(probe_type);
+	free(binary_path);
+	free(func_name);
+	return ret;
+}
+
+#define MAX_BPF_FUNC_ARGS 12
+
+static bool btf_type_is_modifier(const struct btf_type *t)
+{
+	switch (BTF_INFO_KIND(t->info)) {
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_TYPE_TAG:
+		return true;
+	default:
+		return false;
+	}
+}
+
+#define MAX_RESOLVE_DEPTH 32
+
+static int btf_get_type_size(const struct btf *btf, __u32 type_id,
+			     const struct btf_type **ret_type)
+{
+	const struct btf_type *t;
+	int i;
+
+	*ret_type = btf__type_by_id(btf, 0);
+	if (!type_id)
+		return 0;
+	t = btf__type_by_id(btf, type_id);
+	for (i = 0; i < MAX_RESOLVE_DEPTH && t && btf_type_is_modifier(t); i++)
+		t = btf__type_by_id(btf, t->type);
+	if (!t || i == MAX_RESOLVE_DEPTH)
+		return -EINVAL;
+	*ret_type = t;
+	if (btf_is_ptr(t))
+		return btf__pointer_size(btf);
+	if (btf_is_int(t) || btf_is_any_enum(t) || btf_is_struct(t) || btf_is_union(t))
+		return t->size;
+	return -EINVAL;
+}
+
+bool btf_type_is_traceable_func(const struct btf *btf, const struct btf_type *t)
+{
+	const struct btf_param *args;
+	const struct btf_type *proto;
+	__u32 i, nargs;
+	int ret;
+
+	if (!btf_is_func(t))
+		return false;
+	proto = btf__type_by_id(btf, t->type);
+	if (!proto || !btf_is_func_proto(proto))
+		return false;
+
+	args = (const struct btf_param *)(proto + 1);
+	nargs = btf_vlen(proto);
+	if (nargs > MAX_BPF_FUNC_ARGS)
+		return false;
+
+	/* No support for struct return type. */
+	ret = btf_get_type_size(btf, proto->type, &t);
+	if (ret < 0 || btf_is_struct(t) || btf_is_union(t))
+		return false;
+
+	for (i = 0; i < nargs; i++) {
+		/* No support for variable args. */
+		if (i == nargs - 1 && args[i].type == 0)
+			return false;
+		ret = btf_get_type_size(btf, args[i].type, &t);
+		/* No support of struct argument size greater than 16 bytes. */
+		if (ret < 0 || ret > 16)
+			return false;
+		/* No support for void argument. */
+		if (ret == 0)
+			return false;
+	}
+
+	return true;
+}
+
+static int
+collect_btf_func_ids_by_glob(const struct btf *btf, const char *pattern, __u32 **ids)
+{
+	__u32 type_id, nr_types = btf__type_cnt(btf);
+	size_t cap = 0, cnt = 0;
+
+	if (!pattern)
+		return -EINVAL;
+
+	for (type_id = 1; type_id < nr_types; type_id++) {
+		const struct btf_type *t = btf__type_by_id(btf, type_id);
+		const char *name;
+		int err;
+
+		if (btf_kind(t) != BTF_KIND_FUNC)
+			continue;
+		name = btf__name_by_offset(btf, t->name_off);
+		if (!name)
+			continue;
+
+		if (!glob_match(name, pattern))
+			continue;
+		if (!btf_type_is_traceable_func(btf, t))
+			continue;
+
+		err = libbpf_ensure_mem((void **) ids, &cap, sizeof(**ids), cnt + 1);
+		if (err) {
+			free(*ids);
+			return -ENOMEM;
+		}
+		(*ids)[cnt++] = type_id;
+	}
+
+	return cnt;
+}
+
+static int collect_func_ids_by_glob(const struct bpf_program *prog, const char *pattern, __u32 **ids)
+{
+	struct bpf_object *obj = prog->obj;
+	const struct module_btf *mod;
+	struct btf *btf = NULL;
+	const char *sep;
+	int err;
+
+	err = bpf_object__load_vmlinux_btf(obj, true);
+	if (err)
+		return err;
+
+	/* In case we have module specified, we will find its btf and use that. */
+	sep = strchr(pattern, ':');
+	if (sep) {
+		mod = find_attach_module(obj, pattern);
+		if (!mod) {
+			err = -EINVAL;
+			goto cleanup;
+		}
+		btf = mod->btf;
+		pattern = sep + 1;
+	} else {
+		/* Program is loaded for kernel module. */
+		if (prog->attach_btf_obj_fd) {
+			err = -EINVAL;
+			goto cleanup;
+		}
+		btf = obj->btf_vmlinux;
+	}
+
+	err = collect_btf_func_ids_by_glob(btf, pattern, ids);
+
+cleanup:
+	bpf_object_cleanup_btf(obj);
+	return err;
+}
+
+struct bpf_link *
+bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char *pattern,
+				  const struct bpf_tracing_multi_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, lopts);
+	int prog_fd, link_fd, err, cnt;
+	__u32 *free_ids = NULL;
+	struct bpf_link *link;
+	const __u64 *cookies;
+	const __u32 *ids;
+
+	if (!OPTS_VALID(opts, bpf_tracing_multi_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	cnt = OPTS_GET(opts, cnt, 0);
+	ids = OPTS_GET(opts, ids, NULL);
+	cookies = OPTS_GET(opts, cookies, NULL);
+
+	if (!!ids != !!cnt)
+		return libbpf_err_ptr(-EINVAL);
+	if (pattern && (ids || cookies))
+		return libbpf_err_ptr(-EINVAL);
+	if (!pattern && !ids)
+		return libbpf_err_ptr(-EINVAL);
+
+	if (pattern) {
+		cnt = collect_func_ids_by_glob(prog, pattern, &free_ids);
+		if (cnt < 0)
+			return libbpf_err_ptr(cnt);
+		if (cnt == 0)
+			return libbpf_err_ptr(-EINVAL);
+		ids = (const __u32 *) free_ids;
+	}
+
+	lopts.tracing_multi.ids = ids;
+	lopts.tracing_multi.cookies = cookies;
+	lopts.tracing_multi.cnt = cnt;
+
+	link = calloc(1, sizeof(*link));
+	if (!link) {
+		err = -ENOMEM;
+		goto error;
+	}
+	link->detach = &bpf_link__detach_fd;
+
+	link_fd = bpf_link_create(prog_fd, 0, prog->expected_attach_type, &lopts);
+	if (link_fd < 0) {
+		err = -errno;
+		pr_warn("prog '%s': failed to attach: %s\n", prog->name, errstr(err));
+		goto error;
+	}
+	link->fd = link_fd;
+	free(free_ids);
+	return link;
+
+error:
+	free(link);
+	free(free_ids);
+	return libbpf_err_ptr(err);
+}
+
+static int attach_tracing_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	static const char *const prefixes[] = {
+		"fentry.multi",
+		"fexit.multi",
+		"fsession.multi",
+		"fentry.multi.s",
+		"fexit.multi.s",
+		"fsession.multi.s",
+	};
+	const char *spec = NULL;
+	char *pattern;
+	size_t i;
+	int n;
+
+	*link = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
+		size_t pfx_len;
+
+		if (!str_has_pfx(prog->sec_name, prefixes[i]))
+			continue;
+
+		pfx_len = strlen(prefixes[i]);
+		/* no auto-attach case of, e.g., SEC("fentry.multi") */
+		if (prog->sec_name[pfx_len] == '\0')
+			return 0;
+
+		if (prog->sec_name[pfx_len] != '/')
+			continue;
+
+		spec = prog->sec_name + pfx_len + 1;
+		break;
+	}
+
+	if (!spec) {
+		pr_warn("prog '%s': invalid section name '%s'\n",
+			prog->name, prog->sec_name);
+		return -EINVAL;
+	}
+
+	n = sscanf(spec, "%m[a-zA-Z0-9_.*?:]", &pattern);
+	if (n < 1) {
+		pr_warn("tracing multi pattern is invalid: %s\n", spec);
+		return -EINVAL;
+	}
+
+	*link = bpf_program__attach_tracing_multi(prog, pattern, NULL);
+	free(pattern);
+	return libbpf_get_error(*link);
+}
+
+static inline int add_uprobe_event_legacy(const char *probe_name, bool retprobe,
+					  const char *binary_path, size_t offset)
+{
+	return append_to_file(tracefs_uprobe_events(), "%c:%s/%s %s:0x%zx",
+			      retprobe ? 'r' : 'p',
+			      retprobe ? "uretprobes" : "uprobes",
+			      probe_name, binary_path, offset);
+}
+
+static inline int remove_uprobe_event_legacy(const char *probe_name, bool retprobe)
+{
+	return append_to_file(tracefs_uprobe_events(), "-:%s/%s",
+			      retprobe ? "uretprobes" : "uprobes", probe_name);
+}
+
+static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retprobe)
+{
+	char file[512];
+
+	snprintf(file, sizeof(file), "%s/events/%s/%s/id",
+		 tracefs_path(), retprobe ? "uretprobes" : "uprobes", probe_name);
+
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe,
+					 const char *binary_path, size_t offset, int pid)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	struct perf_event_attr attr;
+	int type, pfd, err;
+
+	err = add_uprobe_event_legacy(probe_name, retprobe, binary_path, offset);
+	if (err < 0) {
+		pr_warn("failed to add legacy uprobe event for %s:0x%zx: %s\n",
+			binary_path, (size_t)offset, errstr(err));
+		return err;
+	}
+	type = determine_uprobe_perf_type_legacy(probe_name, retprobe);
+	if (type < 0) {
+		err = type;
+		pr_warn("failed to determine legacy uprobe event id for %s:0x%zx: %s\n",
+			binary_path, offset, errstr(err));
+		goto err_clean_legacy;
+	}
+
+	memset(&attr, 0, attr_sz);
+	attr.size = attr_sz;
+	attr.config = type;
+	attr.type = PERF_TYPE_TRACEPOINT;
+
+	pfd = syscall(__NR_perf_event_open, &attr,
+		      pid < 0 ? -1 : pid, /* pid */
+		      pid == -1 ? 0 : -1, /* cpu */
+		      -1 /* group_fd */,  PERF_FLAG_FD_CLOEXEC);
+	if (pfd < 0) {
+		err = -errno;
+		pr_warn("legacy uprobe perf_event_open() failed: %s\n", errstr(err));
+		goto err_clean_legacy;
+	}
+	return pfd;
+
+err_clean_legacy:
+	/* Clear the newly added legacy uprobe_event */
+	remove_uprobe_event_legacy(probe_name, retprobe);
+	return err;
+}
+
+/* Find offset of function name in archive specified by path. Currently
+ * supported are .zip files that do not compress their contents, as used on
+ * Android in the form of APKs, for example. "file_name" is the name of the ELF
+ * file inside the archive. "func_name" matches symbol name or name@@LIB for
+ * library functions.
+ *
+ * An overview of the APK format specifically provided here:
+ * https://en.wikipedia.org/w/index.php?title=Apk_(file_format)&oldid=1139099120#Package_contents
+ */
+static long elf_find_func_offset_from_archive(const char *archive_path, const char *file_name,
+					      const char *func_name)
+{
+	struct zip_archive *archive;
+	struct zip_entry entry;
+	long ret;
+	Elf *elf;
+
+	archive = zip_archive_open(archive_path);
+	if (IS_ERR(archive)) {
+		ret = PTR_ERR(archive);
+		pr_warn("zip: failed to open %s: %ld\n", archive_path, ret);
+		return ret;
+	}
+
+	ret = zip_archive_find_entry(archive, file_name, &entry);
+	if (ret) {
+		pr_warn("zip: could not find archive member %s in %s: %ld\n", file_name,
+			archive_path, ret);
+		goto out;
+	}
+	pr_debug("zip: found entry for %s in %s at 0x%lx\n", file_name, archive_path,
+		 (unsigned long)entry.data_offset);
+
+	if (entry.compression) {
+		pr_warn("zip: entry %s of %s is compressed and cannot be handled\n", file_name,
+			archive_path);
+		ret = -LIBBPF_ERRNO__FORMAT;
+		goto out;
+	}
+
+	elf = elf_memory((void *)entry.data, entry.data_length);
+	if (!elf) {
+		pr_warn("elf: could not read elf file %s from %s: %s\n", file_name, archive_path,
+			elf_errmsg(-1));
+		ret = -LIBBPF_ERRNO__LIBELF;
+		goto out;
+	}
+
+	ret = elf_find_func_offset(elf, file_name, func_name);
+	if (ret > 0) {
+		pr_debug("elf: symbol address match for %s of %s in %s: 0x%x + 0x%lx = 0x%lx\n",
+			 func_name, file_name, archive_path, entry.data_offset, (unsigned long)ret,
+			 (unsigned long)(ret + entry.data_offset));
+		ret += entry.data_offset;
+	}
+	elf_end(elf);
+
+out:
+	zip_archive_close(archive);
+	return ret;
+}
+
+static const char *arch_specific_lib_paths(void)
+{
+	/*
+	 * Based on https://packages.debian.org/sid/libc6.
+	 *
+	 * Assume that the traced program is built for the same architecture
+	 * as libbpf, which should cover the vast majority of cases.
+	 */
+#if defined(__x86_64__)
+	return "/lib/x86_64-linux-gnu";
+#elif defined(__i386__)
+	return "/lib/i386-linux-gnu";
+#elif defined(__s390x__)
+	return "/lib/s390x-linux-gnu";
+#elif defined(__arm__) && defined(__SOFTFP__)
+	return "/lib/arm-linux-gnueabi";
+#elif defined(__arm__) && !defined(__SOFTFP__)
+	return "/lib/arm-linux-gnueabihf";
+#elif defined(__aarch64__)
+	return "/lib/aarch64-linux-gnu";
+#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 64
+	return "/lib/mips64el-linux-gnuabi64";
+#elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 32
+	return "/lib/mipsel-linux-gnu";
+#elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	return "/lib/powerpc64le-linux-gnu";
+#elif defined(__sparc__) && defined(__arch64__)
+	return "/lib/sparc64-linux-gnu";
+#elif defined(__riscv) && __riscv_xlen == 64
+	return "/lib/riscv64-linux-gnu";
+#else
+	return NULL;
+#endif
+}
+
+/* Get full path to program/shared library. */
+static int resolve_full_path(const char *file, char *result, size_t result_sz)
+{
+	const char *search_paths[4] = {};
+	int i, perm;
+
+	if (str_has_sfx(file, ".so") || strstr(file, ".so.")) {
+		search_paths[0] = getenv("LD_LIBRARY_PATH");
+		search_paths[1] = "/usr/lib64:/usr/lib";
+		search_paths[2] = arch_specific_lib_paths();
+		search_paths[3] = "/lib64:/lib";
+		perm = R_OK;
+	} else {
+		search_paths[0] = getenv("PATH");
+		search_paths[1] = "/usr/bin:/usr/sbin";
+		perm = R_OK | X_OK;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(search_paths); i++) {
+		const char *s;
+
+		if (!search_paths[i])
+			continue;
+		for (s = search_paths[i]; s != NULL; s = strchr(s, ':')) {
+			const char *next_path;
+			int seg_len;
+
+			if (s[0] == ':')
+				s++;
+			next_path = strchr(s, ':');
+			seg_len = next_path ? next_path - s : strlen(s);
+			if (!seg_len)
+				continue;
+			snprintf(result, result_sz, "%.*s/%s", seg_len, s, file);
+			/* ensure it has required permissions */
+			if (faccessat(AT_FDCWD, result, perm, AT_EACCESS) < 0)
+				continue;
+			pr_debug("resolved '%s' to '%s'\n", file, result);
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+struct bpf_link *
+bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
+				 pid_t pid,
+				 const char *path,
+				 const char *func_pattern,
+				 const struct bpf_uprobe_multi_opts *opts)
+{
+	const unsigned long *ref_ctr_offsets = NULL, *offsets = NULL;
+	LIBBPF_OPTS(bpf_link_create_opts, lopts);
+	unsigned long *resolved_offsets = NULL;
+	enum bpf_attach_type attach_type;
+	int err = 0, link_fd, prog_fd;
+	struct bpf_link *link = NULL;
+	char full_path[PATH_MAX];
+	bool retprobe, session;
+	const __u64 *cookies;
+	const char **syms;
+	size_t cnt;
+
+	if (!OPTS_VALID(opts, bpf_uprobe_multi_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	syms = OPTS_GET(opts, syms, NULL);
+	offsets = OPTS_GET(opts, offsets, NULL);
+	ref_ctr_offsets = OPTS_GET(opts, ref_ctr_offsets, NULL);
+	cookies = OPTS_GET(opts, cookies, NULL);
+	cnt = OPTS_GET(opts, cnt, 0);
+	retprobe = OPTS_GET(opts, retprobe, false);
+	session  = OPTS_GET(opts, session, false);
+
+	/*
+	 * User can specify 2 mutually exclusive set of inputs:
+	 *
+	 * 1) use only path/func_pattern/pid arguments
+	 *
+	 * 2) use path/pid with allowed combinations of:
+	 *    syms/offsets/ref_ctr_offsets/cookies/cnt
+	 *
+	 *    - syms and offsets are mutually exclusive
+	 *    - ref_ctr_offsets and cookies are optional
+	 *
+	 * Any other usage results in error.
+	 */
+
+	if (!path)
+		return libbpf_err_ptr(-EINVAL);
+	if (!func_pattern && cnt == 0)
+		return libbpf_err_ptr(-EINVAL);
+
+	if (func_pattern) {
+		if (syms || offsets || ref_ctr_offsets || cookies || cnt)
+			return libbpf_err_ptr(-EINVAL);
+	} else {
+		if (!!syms == !!offsets)
+			return libbpf_err_ptr(-EINVAL);
+	}
+
+	if (retprobe && session)
+		return libbpf_err_ptr(-EINVAL);
+
+	if (func_pattern) {
+		if (!strchr(path, '/')) {
+			err = resolve_full_path(path, full_path, sizeof(full_path));
+			if (err) {
+				pr_warn("prog '%s': failed to resolve full path for '%s': %s\n",
+					prog->name, path, errstr(err));
+				return libbpf_err_ptr(err);
+			}
+			path = full_path;
+		}
+
+		err = elf_resolve_pattern_offsets(path, func_pattern,
+						  &resolved_offsets, &cnt);
+		if (err < 0)
+			return libbpf_err_ptr(err);
+		offsets = resolved_offsets;
+	} else if (syms) {
+		err = elf_resolve_syms_offsets(path, cnt, syms, &resolved_offsets, STT_FUNC);
+		if (err < 0)
+			return libbpf_err_ptr(err);
+		offsets = resolved_offsets;
+	}
+
+	attach_type = session ? BPF_TRACE_UPROBE_SESSION : BPF_TRACE_UPROBE_MULTI;
+
+	lopts.uprobe_multi.path = path;
+	lopts.uprobe_multi.offsets = offsets;
+	lopts.uprobe_multi.ref_ctr_offsets = ref_ctr_offsets;
+	lopts.uprobe_multi.cookies = cookies;
+	lopts.uprobe_multi.cnt = cnt;
+	lopts.uprobe_multi.flags = retprobe ? BPF_F_UPROBE_MULTI_RETURN : 0;
+
+	if (pid == 0)
+		pid = getpid();
+	if (pid > 0)
+		lopts.uprobe_multi.pid = pid;
+
+	link = calloc(1, sizeof(*link));
+	if (!link) {
+		err = -ENOMEM;
+		goto error;
+	}
+	link->detach = &bpf_link__detach_fd;
+
+	link_fd = bpf_link_create(prog_fd, 0, attach_type, &lopts);
+	if (link_fd < 0) {
+		err = -errno;
+		pr_warn("prog '%s': failed to attach multi-uprobe: %s\n",
+			prog->name, errstr(err));
+		goto error;
+	}
+	link->fd = link_fd;
+	free(resolved_offsets);
+	return link;
+
+error:
+	free(resolved_offsets);
+	free(link);
+	return libbpf_err_ptr(err);
+}
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
+				const char *binary_path, size_t func_offset,
+				const struct bpf_uprobe_opts *opts)
+{
+	const char *archive_path = NULL, *archive_sep = NULL;
+	char *legacy_probe = NULL;
+	DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
+	enum probe_attach_mode attach_mode;
+	char full_path[PATH_MAX];
+	struct bpf_link *link;
+	size_t ref_ctr_off;
+	int pfd, err;
+	bool retprobe, legacy;
+	const char *func_name;
+
+	if (!OPTS_VALID(opts, bpf_uprobe_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT);
+	retprobe = OPTS_GET(opts, retprobe, false);
+	ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0);
+	pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+
+	if (!binary_path)
+		return libbpf_err_ptr(-EINVAL);
+
+	/* Check if "binary_path" refers to an archive. */
+	archive_sep = strstr(binary_path, "!/");
+	if (archive_sep) {
+		full_path[0] = '\0';
+		libbpf_strlcpy(full_path, binary_path,
+			       min(sizeof(full_path), (size_t)(archive_sep - binary_path + 1)));
+		archive_path = full_path;
+		binary_path = archive_sep + 2;
+	} else if (!strchr(binary_path, '/')) {
+		err = resolve_full_path(binary_path, full_path, sizeof(full_path));
+		if (err) {
+			pr_warn("prog '%s': failed to resolve full path for '%s': %s\n",
+				prog->name, binary_path, errstr(err));
+			return libbpf_err_ptr(err);
+		}
+		binary_path = full_path;
+	}
+	func_name = OPTS_GET(opts, func_name, NULL);
+	if (func_name) {
+		long sym_off;
+
+		if (archive_path) {
+			sym_off = elf_find_func_offset_from_archive(archive_path, binary_path,
+								    func_name);
+			binary_path = archive_path;
+		} else {
+			sym_off = elf_find_func_offset_from_file(binary_path, func_name);
+		}
+		if (sym_off < 0)
+			return libbpf_err_ptr(sym_off);
+		func_offset += sym_off;
+	}
+
+	legacy = determine_uprobe_perf_type() < 0;
+	switch (attach_mode) {
+	case PROBE_ATTACH_MODE_LEGACY:
+		legacy = true;
+		pe_opts.force_ioctl_attach = true;
+		break;
+	case PROBE_ATTACH_MODE_PERF:
+		if (legacy)
+			return libbpf_err_ptr(-ENOTSUP);
+		pe_opts.force_ioctl_attach = true;
+		break;
+	case PROBE_ATTACH_MODE_LINK:
+		if (legacy || !kernel_supports(prog->obj, FEAT_PERF_LINK))
+			return libbpf_err_ptr(-ENOTSUP);
+		break;
+	case PROBE_ATTACH_MODE_DEFAULT:
+		break;
+	default:
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	if (!legacy) {
+		pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path,
+					    func_offset, pid, ref_ctr_off);
+	} else {
+		char probe_name[MAX_EVENT_NAME_LEN];
+
+		if (ref_ctr_off)
+			return libbpf_err_ptr(-EINVAL);
+
+		gen_probe_legacy_event_name(probe_name, sizeof(probe_name),
+					    strrchr(binary_path, '/') ? : binary_path,
+					    func_offset);
+
+		legacy_probe = strdup(probe_name);
+		if (!legacy_probe)
+			return libbpf_err_ptr(-ENOMEM);
+
+		pfd = perf_event_uprobe_open_legacy(legacy_probe, retprobe,
+						    binary_path, func_offset, pid);
+	}
+	if (pfd < 0) {
+		err = pfd;
+		pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
+			prog->name, retprobe ? "uretprobe" : "uprobe",
+			binary_path, func_offset,
+			errstr(err));
+		goto err_out;
+	}
+
+	link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
+	err = libbpf_get_error(link);
+	if (err) {
+		close(pfd);
+		pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n",
+			prog->name, retprobe ? "uretprobe" : "uprobe",
+			binary_path, func_offset,
+			errstr(err));
+		goto err_clean_legacy;
+	}
+	if (legacy) {
+		struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link);
+
+		perf_link->legacy_probe_name = legacy_probe;
+		perf_link->legacy_is_kprobe = false;
+		perf_link->legacy_is_retprobe = retprobe;
+	}
+	return link;
+
+err_clean_legacy:
+	if (legacy)
+		remove_uprobe_event_legacy(legacy_probe, retprobe);
+err_out:
+	free(legacy_probe);
+	return libbpf_err_ptr(err);
+}
+
+/* Format of u[ret]probe section definition supporting auto-attach:
+ * u[ret]probe/binary:function[+offset]
+ *
+ * binary can be an absolute/relative path or a filename; the latter is resolved to a
+ * full binary path via bpf_program__attach_uprobe_opts.
+ *
+ * Specifying uprobe+ ensures we carry out strict matching; either "uprobe" must be
+ * specified (and auto-attach is not possible) or the above format is specified for
+ * auto-attach.
+ */
+static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts);
+	char *probe_type = NULL, *binary_path = NULL, *func_name = NULL, *func_off;
+	int n, c, ret = -EINVAL;
+	long offset = 0;
+
+	*link = NULL;
+
+	n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[^\n]",
+		   &probe_type, &binary_path, &func_name);
+	switch (n) {
+	case 1:
+		/* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */
+		ret = 0;
+		break;
+	case 2:
+		pr_warn("prog '%s': section '%s' missing ':function[+offset]' specification\n",
+			prog->name, prog->sec_name);
+		break;
+	case 3:
+		/* check if user specifies `+offset`, if yes, this should be
+		 * the last part of the string, make sure sscanf read to EOL
+		 */
+		func_off = strrchr(func_name, '+');
+		if (func_off) {
+			n = sscanf(func_off, "+%li%n", &offset, &c);
+			if (n == 1 && *(func_off + c) == '\0')
+				func_off[0] = '\0';
+			else
+				offset = 0;
+		}
+		opts.retprobe = strcmp(probe_type, "uretprobe") == 0 ||
+				strcmp(probe_type, "uretprobe.s") == 0;
+		if (opts.retprobe && offset != 0) {
+			pr_warn("prog '%s': uretprobes do not support offset specification\n",
+				prog->name);
+			break;
+		}
+		opts.func_name = func_name;
+		*link = bpf_program__attach_uprobe_opts(prog, -1, binary_path, offset, &opts);
+		ret = libbpf_get_error(*link);
+		break;
+	default:
+		pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name,
+			prog->sec_name);
+		break;
+	}
+	free(probe_type);
+	free(binary_path);
+	free(func_name);
+
+	return ret;
+}
+
+struct bpf_link *bpf_program__attach_uprobe(const struct bpf_program *prog,
+					    bool retprobe, pid_t pid,
+					    const char *binary_path,
+					    size_t func_offset)
+{
+	DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts, .retprobe = retprobe);
+
+	return bpf_program__attach_uprobe_opts(prog, pid, binary_path, func_offset, &opts);
+}
+
+struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog,
+					  pid_t pid, const char *binary_path,
+					  const char *usdt_provider, const char *usdt_name,
+					  const struct bpf_usdt_opts *opts)
+{
+	char resolved_path[512];
+	struct bpf_object *obj = prog->obj;
+	struct bpf_link *link;
+	__u64 usdt_cookie;
+	int err;
+
+	if (!OPTS_VALID(opts, bpf_uprobe_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	if (bpf_program__fd(prog) < 0) {
+		pr_warn("prog '%s': can't attach BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	if (!binary_path)
+		return libbpf_err_ptr(-EINVAL);
+
+	if (!strchr(binary_path, '/')) {
+		err = resolve_full_path(binary_path, resolved_path, sizeof(resolved_path));
+		if (err) {
+			pr_warn("prog '%s': failed to resolve full path for '%s': %s\n",
+				prog->name, binary_path, errstr(err));
+			return libbpf_err_ptr(err);
+		}
+		binary_path = resolved_path;
+	}
+
+	/* USDT manager is instantiated lazily on first USDT attach. It will
+	 * be destroyed together with BPF object in bpf_object__close().
+	 */
+	if (IS_ERR(obj->usdt_man))
+		return libbpf_ptr(obj->usdt_man);
+	if (!obj->usdt_man) {
+		obj->usdt_man = usdt_manager_new(obj);
+		if (IS_ERR(obj->usdt_man))
+			return libbpf_ptr(obj->usdt_man);
+	}
+
+	usdt_cookie = OPTS_GET(opts, usdt_cookie, 0);
+	link = usdt_manager_attach_usdt(obj->usdt_man, prog, pid, binary_path,
+					usdt_provider, usdt_name, usdt_cookie);
+	err = libbpf_get_error(link);
+	if (err)
+		return libbpf_err_ptr(err);
+	return link;
+}
+
+static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	char *path = NULL, *provider = NULL, *name = NULL;
+	const char *sec_name;
+	int n, err;
+
+	sec_name = bpf_program__section_name(prog);
+	if (strcmp(sec_name, "usdt") == 0) {
+		/* no auto-attach for just SEC("usdt") */
+		*link = NULL;
+		return 0;
+	}
+
+	n = sscanf(sec_name, "usdt/%m[^:]:%m[^:]:%m[^:]", &path, &provider, &name);
+	if (n != 3) {
+		pr_warn("invalid section '%s', expected SEC(\"usdt/<path>:<provider>:<name>\")\n",
+			sec_name);
+		err = -EINVAL;
+	} else {
+		*link = bpf_program__attach_usdt(prog, -1 /* any process */, path,
+						 provider, name, NULL);
+		err = libbpf_get_error(*link);
+	}
+	free(path);
+	free(provider);
+	free(name);
+	return err;
+}
+
+static int determine_tracepoint_id(const char *tp_category,
+				   const char *tp_name)
+{
+	char file[PATH_MAX];
+	int ret;
+
+	ret = snprintf(file, sizeof(file), "%s/events/%s/%s/id",
+		       tracefs_path(), tp_category, tp_name);
+	if (ret < 0)
+		return -errno;
+	if (ret >= sizeof(file)) {
+		pr_debug("tracepoint %s/%s path is too long\n",
+			 tp_category, tp_name);
+		return -E2BIG;
+	}
+	return parse_uint_from_file(file, "%d\n");
+}
+
+static int perf_event_open_tracepoint(const char *tp_category,
+				      const char *tp_name)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	struct perf_event_attr attr;
+	int tp_id, pfd, err;
+
+	tp_id = determine_tracepoint_id(tp_category, tp_name);
+	if (tp_id < 0) {
+		pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
+			tp_category, tp_name,
+			errstr(tp_id));
+		return tp_id;
+	}
+
+	memset(&attr, 0, attr_sz);
+	attr.type = PERF_TYPE_TRACEPOINT;
+	attr.size = attr_sz;
+	attr.config = tp_id;
+
+	pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
+		      -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
+	if (pfd < 0) {
+		err = -errno;
+		pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
+			tp_category, tp_name,
+			errstr(err));
+		return err;
+	}
+	return pfd;
+}
+
+struct bpf_link *bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
+						     const char *tp_category,
+						     const char *tp_name,
+						     const struct bpf_tracepoint_opts *opts)
+{
+	DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts);
+	struct bpf_link *link;
+	int pfd, err;
+
+	if (!OPTS_VALID(opts, bpf_tracepoint_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+
+	pfd = perf_event_open_tracepoint(tp_category, tp_name);
+	if (pfd < 0) {
+		pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
+			prog->name, tp_category, tp_name,
+			errstr(pfd));
+		return libbpf_err_ptr(pfd);
+	}
+	link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
+	err = libbpf_get_error(link);
+	if (err) {
+		close(pfd);
+		pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n",
+			prog->name, tp_category, tp_name,
+			errstr(err));
+		return libbpf_err_ptr(err);
+	}
+	return link;
+}
+
+struct bpf_link *bpf_program__attach_tracepoint(const struct bpf_program *prog,
+						const char *tp_category,
+						const char *tp_name)
+{
+	return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL);
+}
+
+/*
+ * Match section name against a prefix array. Returns pointer past
+ * "prefix/" on match, empty string for bare sections (exact prefix
+ * match), or NULL if no prefix matches.
+ */
+static const char *sec_name_match_prefix(const char *sec_name,
+					 const char *const *prefixes,
+					 size_t n)
+{
+	size_t i;
+
+	for (i = 0; i < n; i++) {
+		size_t pfx_len;
+
+		if (!str_has_pfx(sec_name, prefixes[i]))
+			continue;
+
+		pfx_len = strlen(prefixes[i]);
+		if (sec_name[pfx_len] == '\0')
+			return sec_name + pfx_len;
+
+		if (sec_name[pfx_len] != '/' || sec_name[pfx_len + 1] == '\0')
+			continue;
+
+		return sec_name + pfx_len + 1;
+	}
+	return NULL;
+}
+
+static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	static const char *const prefixes[] = {
+		"tp.s",
+		"tp",
+		"tracepoint.s",
+		"tracepoint",
+	};
+	char *sec_name, *tp_cat, *tp_name;
+	const char *match;
+
+	*link = NULL;
+
+	match = sec_name_match_prefix(prog->sec_name, prefixes, ARRAY_SIZE(prefixes));
+	if (!match) {
+		pr_warn("prog '%s': invalid section name '%s'\n", prog->name, prog->sec_name);
+		return -EINVAL;
+	}
+	if (!match[0]) /* bare section name no autoattach */
+		return 0;
+
+	sec_name = strdup(prog->sec_name);
+	if (!sec_name)
+		return -ENOMEM;
+
+	tp_cat = sec_name + (match - prog->sec_name);
+	tp_name = strchr(tp_cat, '/');
+	if (!tp_name) {
+		free(sec_name);
+		return -EINVAL;
+	}
+	*tp_name = '\0';
+	tp_name++;
+
+	*link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name);
+	free(sec_name);
+	return libbpf_get_error(*link);
+}
+
+struct bpf_link *
+bpf_program__attach_raw_tracepoint_opts(const struct bpf_program *prog,
+					const char *tp_name,
+					struct bpf_raw_tracepoint_opts *opts)
+{
+	LIBBPF_OPTS(bpf_raw_tp_opts, raw_opts);
+	struct bpf_link *link;
+	int prog_fd, pfd;
+
+	if (!OPTS_VALID(opts, bpf_raw_tracepoint_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+	link->detach = &bpf_link__detach_fd;
+
+	raw_opts.tp_name = tp_name;
+	raw_opts.cookie = OPTS_GET(opts, cookie, 0);
+	pfd = bpf_raw_tracepoint_open_opts(prog_fd, &raw_opts);
+	if (pfd < 0) {
+		pfd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n",
+			prog->name, tp_name, errstr(pfd));
+		return libbpf_err_ptr(pfd);
+	}
+	link->fd = pfd;
+	return link;
+}
+
+struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
+						    const char *tp_name)
+{
+	return bpf_program__attach_raw_tracepoint_opts(prog, tp_name, NULL);
+}
+
+static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	static const char *const prefixes[] = {
+		"raw_tp",
+		"raw_tracepoint",
+		"raw_tp.w",
+		"raw_tracepoint.w",
+		"raw_tp.s",
+		"raw_tracepoint.s",
+	};
+	const char *match;
+
+	*link = NULL;
+
+	match = sec_name_match_prefix(prog->sec_name, prefixes, ARRAY_SIZE(prefixes));
+	if (!match) {
+		pr_warn("prog '%s': invalid section name '%s'\n", prog->name, prog->sec_name);
+		return -EINVAL;
+	}
+	if (!match[0])
+		return 0;
+
+	*link = bpf_program__attach_raw_tracepoint(prog, match);
+	return libbpf_get_error(*link);
+}
+
+/* Common logic for all BPF program types that attach to a btf_id */
+static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog,
+						   const struct bpf_trace_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, link_opts);
+	struct bpf_link *link;
+	int prog_fd, pfd;
+
+	if (!OPTS_VALID(opts, bpf_trace_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+	link->detach = &bpf_link__detach_fd;
+
+	/* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */
+	link_opts.tracing.cookie = OPTS_GET(opts, cookie, 0);
+	pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), &link_opts);
+	if (pfd < 0) {
+		pfd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach: %s\n",
+			prog->name, errstr(pfd));
+		return libbpf_err_ptr(pfd);
+	}
+	link->fd = pfd;
+	return link;
+}
+
+struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog)
+{
+	return bpf_program__attach_btf_id(prog, NULL);
+}
+
+struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog,
+						const struct bpf_trace_opts *opts)
+{
+	return bpf_program__attach_btf_id(prog, opts);
+}
+
+struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog)
+{
+	return bpf_program__attach_btf_id(prog, NULL);
+}
+
+static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	*link = bpf_program__attach_trace(prog);
+	return libbpf_get_error(*link);
+}
+
+static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	*link = bpf_program__attach_lsm(prog);
+	return libbpf_get_error(*link);
+}
+
+static struct bpf_link *
+bpf_program_attach_fd(const struct bpf_program *prog,
+		      int target_fd, const char *target_name,
+		      const struct bpf_link_create_opts *opts)
+{
+	enum bpf_attach_type attach_type;
+	struct bpf_link *link;
+	int prog_fd, link_fd;
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+	link->detach = &bpf_link__detach_fd;
+
+	attach_type = bpf_program__expected_attach_type(prog);
+	link_fd = bpf_link_create(prog_fd, target_fd, attach_type, opts);
+	if (link_fd < 0) {
+		link_fd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach to %s: %s\n",
+			prog->name, target_name,
+			errstr(link_fd));
+		return libbpf_err_ptr(link_fd);
+	}
+	link->fd = link_fd;
+	return link;
+}
+
+struct bpf_link *
+bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd)
+{
+	return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", NULL);
+}
+
+struct bpf_link *
+bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd)
+{
+	return bpf_program_attach_fd(prog, netns_fd, "netns", NULL);
+}
+
+struct bpf_link *
+bpf_program__attach_sockmap(const struct bpf_program *prog, int map_fd)
+{
+	return bpf_program_attach_fd(prog, map_fd, "sockmap", NULL);
+}
+
+struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex)
+{
+	/* target_fd/target_ifindex use the same field in LINK_CREATE */
+	return bpf_program_attach_fd(prog, ifindex, "xdp", NULL);
+}
+
+struct bpf_link *
+bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd,
+				const struct bpf_cgroup_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
+	__u32 relative_id;
+	int relative_fd;
+
+	if (!OPTS_VALID(opts, bpf_cgroup_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	relative_id = OPTS_GET(opts, relative_id, 0);
+	relative_fd = OPTS_GET(opts, relative_fd, 0);
+
+	if (relative_fd && relative_id) {
+		pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link_create_opts.cgroup.expected_revision = OPTS_GET(opts, expected_revision, 0);
+	link_create_opts.cgroup.relative_fd = relative_fd;
+	link_create_opts.cgroup.relative_id = relative_id;
+	link_create_opts.flags = OPTS_GET(opts, flags, 0);
+
+	return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", &link_create_opts);
+}
+
+struct bpf_link *
+bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
+			const struct bpf_tcx_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
+	__u32 relative_id;
+	int relative_fd;
+
+	if (!OPTS_VALID(opts, bpf_tcx_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	relative_id = OPTS_GET(opts, relative_id, 0);
+	relative_fd = OPTS_GET(opts, relative_fd, 0);
+
+	/* validate we don't have unexpected combinations of non-zero fields */
+	if (!ifindex) {
+		pr_warn("prog '%s': target netdevice ifindex cannot be zero\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+	if (relative_fd && relative_id) {
+		pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link_create_opts.tcx.expected_revision = OPTS_GET(opts, expected_revision, 0);
+	link_create_opts.tcx.relative_fd = relative_fd;
+	link_create_opts.tcx.relative_id = relative_id;
+	link_create_opts.flags = OPTS_GET(opts, flags, 0);
+
+	/* target_fd/target_ifindex use the same field in LINK_CREATE */
+	return bpf_program_attach_fd(prog, ifindex, "tcx", &link_create_opts);
+}
+
+struct bpf_link *
+bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex,
+			   const struct bpf_netkit_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
+	__u32 relative_id;
+	int relative_fd;
+
+	if (!OPTS_VALID(opts, bpf_netkit_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	relative_id = OPTS_GET(opts, relative_id, 0);
+	relative_fd = OPTS_GET(opts, relative_fd, 0);
+
+	/* validate we don't have unexpected combinations of non-zero fields */
+	if (!ifindex) {
+		pr_warn("prog '%s': target netdevice ifindex cannot be zero\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+	if (relative_fd && relative_id) {
+		pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link_create_opts.netkit.expected_revision = OPTS_GET(opts, expected_revision, 0);
+	link_create_opts.netkit.relative_fd = relative_fd;
+	link_create_opts.netkit.relative_id = relative_id;
+	link_create_opts.flags = OPTS_GET(opts, flags, 0);
+
+	return bpf_program_attach_fd(prog, ifindex, "netkit", &link_create_opts);
+}
+
+struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
+					      int target_fd,
+					      const char *attach_func_name)
+{
+	int btf_id;
+
+	if (!!target_fd != !!attach_func_name) {
+		pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	if (prog->type != BPF_PROG_TYPE_EXT) {
+		pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	if (target_fd) {
+		LIBBPF_OPTS(bpf_link_create_opts, target_opts);
+
+		btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd, prog->obj->token_fd);
+		if (btf_id < 0)
+			return libbpf_err_ptr(btf_id);
+
+		target_opts.target_btf_id = btf_id;
+
+		return bpf_program_attach_fd(prog, target_fd, "freplace",
+					     &target_opts);
+	} else {
+		/* no target, so use raw_tracepoint_open for compatibility
+		 * with old kernels
+		 */
+		return bpf_program__attach_trace(prog);
+	}
+}
+
+struct bpf_link *
+bpf_program__attach_iter(const struct bpf_program *prog,
+			 const struct bpf_iter_attach_opts *opts)
+{
+	DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
+	struct bpf_link *link;
+	int prog_fd, link_fd;
+	__u32 target_fd = 0;
+
+	if (!OPTS_VALID(opts, bpf_iter_attach_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0);
+	link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+	link->detach = &bpf_link__detach_fd;
+
+	link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER,
+				  &link_create_opts);
+	if (link_fd < 0) {
+		link_fd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach to iterator: %s\n",
+			prog->name, errstr(link_fd));
+		return libbpf_err_ptr(link_fd);
+	}
+	link->fd = link_fd;
+	return link;
+}
+
+static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+	*link = bpf_program__attach_iter(prog, NULL);
+	return libbpf_get_error(*link);
+}
+
+struct bpf_link *bpf_program__attach_netfilter(const struct bpf_program *prog,
+					       const struct bpf_netfilter_opts *opts)
+{
+	LIBBPF_OPTS(bpf_link_create_opts, lopts);
+	struct bpf_link *link;
+	int prog_fd, link_fd;
+
+	if (!OPTS_VALID(opts, bpf_netfilter_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-ENOMEM);
+
+	link->detach = &bpf_link__detach_fd;
+
+	lopts.netfilter.pf = OPTS_GET(opts, pf, 0);
+	lopts.netfilter.hooknum = OPTS_GET(opts, hooknum, 0);
+	lopts.netfilter.priority = OPTS_GET(opts, priority, 0);
+	lopts.netfilter.flags = OPTS_GET(opts, flags, 0);
+
+	link_fd = bpf_link_create(prog_fd, 0, BPF_NETFILTER, &lopts);
+	if (link_fd < 0) {
+		link_fd = -errno;
+		free(link);
+		pr_warn("prog '%s': failed to attach to netfilter: %s\n",
+			prog->name, errstr(link_fd));
+		return libbpf_err_ptr(link_fd);
+	}
+	link->fd = link_fd;
+
+	return link;
+}
+
+struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
+{
+	struct bpf_link *link = NULL;
+	int err;
+
+	if (!prog->sec_def || !prog->sec_def->prog_attach_fn)
+		return libbpf_err_ptr(-EOPNOTSUPP);
+
+	if (bpf_program__fd(prog) < 0) {
+		pr_warn("prog '%s': can't attach BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, &link);
+	if (err)
+		return libbpf_err_ptr(err);
+
+	/* When calling bpf_program__attach() explicitly, auto-attach support
+	 * is expected to work, so NULL returned link is considered an error.
+	 * This is different for skeleton's attach, see comment in
+	 * bpf_object__attach_skeleton().
+	 */
+	if (!link)
+		return libbpf_err_ptr(-EOPNOTSUPP);
+
+	return link;
+}
+
+struct bpf_link_struct_ops {
+	struct bpf_link link;
+	int map_fd;
+};
+
+static int bpf_link__detach_struct_ops(struct bpf_link *link)
+{
+	struct bpf_link_struct_ops *st_link;
+	__u32 zero = 0;
+
+	st_link = container_of(link, struct bpf_link_struct_ops, link);
+
+	if (st_link->map_fd < 0)
+		/* w/o a real link */
+		return bpf_map_delete_elem(link->fd, &zero);
+
+	return close(link->fd);
+}
+
+struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map)
+{
+	struct bpf_link_struct_ops *link;
+	__u32 zero = 0;
+	int err, fd;
+
+	if (!bpf_map__is_struct_ops(map)) {
+		pr_warn("map '%s': can't attach non-struct_ops map\n", map->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	if (map->fd < 0) {
+		pr_warn("map '%s': can't attach BPF map without FD (was it created?)\n", map->name);
+		return libbpf_err_ptr(-EINVAL);
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link)
+		return libbpf_err_ptr(-EINVAL);
+
+	/* kern_vdata should be prepared during the loading phase. */
+	err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0);
+	/* It can be EBUSY if the map has been used to create or
+	 * update a link before.  We don't allow updating the value of
+	 * a struct_ops once it is set.  That ensures that the value
+	 * never changed.  So, it is safe to skip EBUSY.
+	 */
+	if (err && (!(map->def.map_flags & BPF_F_LINK) || err != -EBUSY)) {
+		free(link);
+		return libbpf_err_ptr(err);
+	}
+
+	link->link.detach = bpf_link__detach_struct_ops;
+
+	if (!(map->def.map_flags & BPF_F_LINK)) {
+		/* w/o a real link */
+		link->link.fd = map->fd;
+		link->map_fd = -1;
+		return &link->link;
+	}
+
+	fd = bpf_link_create(map->fd, 0, BPF_STRUCT_OPS, NULL);
+	if (fd < 0) {
+		free(link);
+		return libbpf_err_ptr(fd);
+	}
+
+	link->link.fd = fd;
+	link->map_fd = map->fd;
+
+	return &link->link;
+}
+
+/*
+ * Swap the back struct_ops of a link with a new struct_ops map.
+ */
+int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map)
+{
+	struct bpf_link_struct_ops *st_ops_link;
+	__u32 zero = 0;
+	int err;
+
+	if (!bpf_map__is_struct_ops(map))
+		return libbpf_err(-EINVAL);
+
+	if (map->fd < 0) {
+		pr_warn("map '%s': can't use BPF map without FD (was it created?)\n", map->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	st_ops_link = container_of(link, struct bpf_link_struct_ops, link);
+	/* Ensure the type of a link is correct */
+	if (st_ops_link->map_fd < 0)
+		return libbpf_err(-EINVAL);
+
+	err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0);
+	/* It can be EBUSY if the map has been used to create or
+	 * update a link before.  We don't allow updating the value of
+	 * a struct_ops once it is set.  That ensures that the value
+	 * never changed.  So, it is safe to skip EBUSY.
+	 */
+	if (err && err != -EBUSY)
+		return err;
+
+	err = bpf_link_update(link->fd, map->fd, NULL);
+	if (err < 0)
+		return err;
+
+	st_ops_link->map_fd = map->fd;
+
+	return 0;
+}
+
+typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr,
+							  void *private_data);
+
+static enum bpf_perf_event_ret
+perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
+		       void **copy_mem, size_t *copy_size,
+		       bpf_perf_event_print_t fn, void *private_data)
+{
+	struct perf_event_mmap_page *header = mmap_mem;
+	__u64 data_head = ring_buffer_read_head(header);
+	__u64 data_tail = header->data_tail;
+	void *base = ((__u8 *)header) + page_size;
+	int ret = LIBBPF_PERF_EVENT_CONT;
+	struct perf_event_header *ehdr;
+	size_t ehdr_size;
+
+	while (data_head != data_tail) {
+		ehdr = base + (data_tail & (mmap_size - 1));
+		ehdr_size = ehdr->size;
+
+		if (((void *)ehdr) + ehdr_size > base + mmap_size) {
+			void *copy_start = ehdr;
+			size_t len_first = base + mmap_size - copy_start;
+			size_t len_second = ehdr_size - len_first;
+
+			if (*copy_size < ehdr_size) {
+				free(*copy_mem);
+				*copy_mem = malloc(ehdr_size);
+				if (!*copy_mem) {
+					*copy_size = 0;
+					ret = LIBBPF_PERF_EVENT_ERROR;
+					break;
+				}
+				*copy_size = ehdr_size;
+			}
+
+			memcpy(*copy_mem, copy_start, len_first);
+			memcpy(*copy_mem + len_first, base, len_second);
+			ehdr = *copy_mem;
+		}
+
+		ret = fn(ehdr, private_data);
+		data_tail += ehdr_size;
+		if (ret != LIBBPF_PERF_EVENT_CONT)
+			break;
+	}
+
+	ring_buffer_write_tail(header, data_tail);
+	return libbpf_err(ret);
+}
+
+struct perf_buffer;
+
+struct perf_buffer_params {
+	struct perf_event_attr *attr;
+	/* if event_cb is specified, it takes precedence */
+	perf_buffer_event_fn event_cb;
+	/* sample_cb and lost_cb are higher-level common-case callbacks */
+	perf_buffer_sample_fn sample_cb;
+	perf_buffer_lost_fn lost_cb;
+	void *ctx;
+	int cpu_cnt;
+	int *cpus;
+	int *map_keys;
+};
+
+struct perf_cpu_buf {
+	struct perf_buffer *pb;
+	void *base; /* mmap()'ed memory */
+	void *buf; /* for reconstructing segmented data */
+	size_t buf_size;
+	int fd;
+	int cpu;
+	int map_key;
+};
+
+struct perf_buffer {
+	perf_buffer_event_fn event_cb;
+	perf_buffer_sample_fn sample_cb;
+	perf_buffer_lost_fn lost_cb;
+	void *ctx; /* passed into callbacks */
+
+	size_t page_size;
+	size_t mmap_size;
+	struct perf_cpu_buf **cpu_bufs;
+	struct epoll_event *events;
+	int cpu_cnt; /* number of allocated CPU buffers */
+	int epoll_fd; /* perf event FD */
+	int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
+};
+
+static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
+				      struct perf_cpu_buf *cpu_buf)
+{
+	if (!cpu_buf)
+		return;
+	if (cpu_buf->base &&
+	    munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
+		pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
+	if (cpu_buf->fd >= 0) {
+		ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
+		close(cpu_buf->fd);
+	}
+	free(cpu_buf->buf);
+	free(cpu_buf);
+}
+
+void perf_buffer__free(struct perf_buffer *pb)
+{
+	int i;
+
+	if (IS_ERR_OR_NULL(pb))
+		return;
+	if (pb->cpu_bufs) {
+		for (i = 0; i < pb->cpu_cnt; i++) {
+			struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
+
+			if (!cpu_buf)
+				continue;
+
+			bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
+			perf_buffer__free_cpu_buf(pb, cpu_buf);
+		}
+		free(pb->cpu_bufs);
+	}
+	if (pb->epoll_fd >= 0)
+		close(pb->epoll_fd);
+	free(pb->events);
+	free(pb);
+}
+
+static struct perf_cpu_buf *
+perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
+			  int cpu, int map_key)
+{
+	struct perf_cpu_buf *cpu_buf;
+	int err;
+
+	cpu_buf = calloc(1, sizeof(*cpu_buf));
+	if (!cpu_buf)
+		return ERR_PTR(-ENOMEM);
+
+	cpu_buf->pb = pb;
+	cpu_buf->cpu = cpu;
+	cpu_buf->map_key = map_key;
+
+	cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
+			      -1, PERF_FLAG_FD_CLOEXEC);
+	if (cpu_buf->fd < 0) {
+		err = -errno;
+		pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
+			cpu, errstr(err));
+		goto error;
+	}
+
+	cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
+			     PROT_READ | PROT_WRITE, MAP_SHARED,
+			     cpu_buf->fd, 0);
+	if (cpu_buf->base == MAP_FAILED) {
+		cpu_buf->base = NULL;
+		err = -errno;
+		pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
+			cpu, errstr(err));
+		goto error;
+	}
+
+	if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
+		err = -errno;
+		pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
+			cpu, errstr(err));
+		goto error;
+	}
+
+	return cpu_buf;
+
+error:
+	perf_buffer__free_cpu_buf(pb, cpu_buf);
+	return (struct perf_cpu_buf *)ERR_PTR(err);
+}
+
+static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
+					      struct perf_buffer_params *p);
+
+struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
+				     perf_buffer_sample_fn sample_cb,
+				     perf_buffer_lost_fn lost_cb,
+				     void *ctx,
+				     const struct perf_buffer_opts *opts)
+{
+	const size_t attr_sz = sizeof(struct perf_event_attr);
+	struct perf_buffer_params p = {};
+	struct perf_event_attr attr;
+	__u32 sample_period;
+
+	if (!OPTS_VALID(opts, perf_buffer_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	sample_period = OPTS_GET(opts, sample_period, 1);
+	if (!sample_period)
+		sample_period = 1;
+
+	memset(&attr, 0, attr_sz);
+	attr.size = attr_sz;
+	attr.config = PERF_COUNT_SW_BPF_OUTPUT;
+	attr.type = PERF_TYPE_SOFTWARE;
+	attr.sample_type = PERF_SAMPLE_RAW;
+	attr.wakeup_events = sample_period;
+
+	p.attr = &attr;
+	p.sample_cb = sample_cb;
+	p.lost_cb = lost_cb;
+	p.ctx = ctx;
+
+	return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p));
+}
+
+struct perf_buffer *perf_buffer__new_raw(int map_fd, size_t page_cnt,
+					 struct perf_event_attr *attr,
+					 perf_buffer_event_fn event_cb, void *ctx,
+					 const struct perf_buffer_raw_opts *opts)
+{
+	struct perf_buffer_params p = {};
+
+	if (!attr)
+		return libbpf_err_ptr(-EINVAL);
+
+	if (!OPTS_VALID(opts, perf_buffer_raw_opts))
+		return libbpf_err_ptr(-EINVAL);
+
+	p.attr = attr;
+	p.event_cb = event_cb;
+	p.ctx = ctx;
+	p.cpu_cnt = OPTS_GET(opts, cpu_cnt, 0);
+	p.cpus = OPTS_GET(opts, cpus, NULL);
+	p.map_keys = OPTS_GET(opts, map_keys, NULL);
+
+	return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p));
+}
+
+static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
+					      struct perf_buffer_params *p)
+{
+	const char *online_cpus_file = "/sys/devices/system/cpu/online";
+	struct bpf_map_info map;
+	struct perf_buffer *pb;
+	bool *online = NULL;
+	__u32 map_info_len;
+	int err, i, j, n;
+
+	if (page_cnt == 0 || (page_cnt & (page_cnt - 1))) {
+		pr_warn("page count should be power of two, but is %zu\n",
+			page_cnt);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* best-effort sanity checks */
+	memset(&map, 0, sizeof(map));
+	map_info_len = sizeof(map);
+	err = bpf_map_get_info_by_fd(map_fd, &map, &map_info_len);
+	if (err) {
+		err = -errno;
+		/* if BPF_OBJ_GET_INFO_BY_FD is supported, will return
+		 * -EBADFD, -EFAULT, or -E2BIG on real error
+		 */
+		if (err != -EINVAL) {
+			pr_warn("failed to get map info for map FD %d: %s\n",
+				map_fd, errstr(err));
+			return ERR_PTR(err);
+		}
+		pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n",
+			 map_fd);
+	} else {
+		if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
+			pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
+				map.name);
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	pb = calloc(1, sizeof(*pb));
+	if (!pb)
+		return ERR_PTR(-ENOMEM);
+
+	pb->event_cb = p->event_cb;
+	pb->sample_cb = p->sample_cb;
+	pb->lost_cb = p->lost_cb;
+	pb->ctx = p->ctx;
+
+	pb->page_size = getpagesize();
+	pb->mmap_size = pb->page_size * page_cnt;
+	pb->map_fd = map_fd;
+
+	pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+	if (pb->epoll_fd < 0) {
+		err = -errno;
+		pr_warn("failed to create epoll instance: %s\n",
+			errstr(err));
+		goto error;
+	}
+
+	if (p->cpu_cnt > 0) {
+		pb->cpu_cnt = p->cpu_cnt;
+	} else {
+		pb->cpu_cnt = libbpf_num_possible_cpus();
+		if (pb->cpu_cnt < 0) {
+			err = pb->cpu_cnt;
+			goto error;
+		}
+		if (map.max_entries && map.max_entries < pb->cpu_cnt)
+			pb->cpu_cnt = map.max_entries;
+	}
+
+	pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
+	if (!pb->events) {
+		err = -ENOMEM;
+		pr_warn("failed to allocate events: out of memory\n");
+		goto error;
+	}
+	pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
+	if (!pb->cpu_bufs) {
+		err = -ENOMEM;
+		pr_warn("failed to allocate buffers: out of memory\n");
+		goto error;
+	}
+
+	err = parse_cpu_mask_file(online_cpus_file, &online, &n);
+	if (err) {
+		pr_warn("failed to get online CPU mask: %s\n", errstr(err));
+		goto error;
+	}
+
+	for (i = 0, j = 0; i < pb->cpu_cnt; i++) {
+		struct perf_cpu_buf *cpu_buf;
+		int cpu, map_key;
+
+		cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
+		map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
+
+		/* in case user didn't explicitly requested particular CPUs to
+		 * be attached to, skip offline/not present CPUs
+		 */
+		if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu]))
+			continue;
+
+		cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
+		if (IS_ERR(cpu_buf)) {
+			err = PTR_ERR(cpu_buf);
+			goto error;
+		}
+
+		pb->cpu_bufs[j] = cpu_buf;
+
+		err = bpf_map_update_elem(pb->map_fd, &map_key,
+					  &cpu_buf->fd, 0);
+		if (err) {
+			err = -errno;
+			pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
+				cpu, map_key, cpu_buf->fd,
+				errstr(err));
+			goto error;
+		}
+
+		pb->events[j].events = EPOLLIN;
+		pb->events[j].data.ptr = cpu_buf;
+		if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
+			      &pb->events[j]) < 0) {
+			err = -errno;
+			pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
+				cpu, cpu_buf->fd,
+				errstr(err));
+			goto error;
+		}
+		j++;
+	}
+	pb->cpu_cnt = j;
+	free(online);
+
+	return pb;
+
+error:
+	free(online);
+	if (pb)
+		perf_buffer__free(pb);
+	return ERR_PTR(err);
+}
+
+struct perf_sample_raw {
+	struct perf_event_header header;
+	uint32_t size;
+	char data[];
+};
+
+struct perf_sample_lost {
+	struct perf_event_header header;
+	uint64_t id;
+	uint64_t lost;
+	uint64_t sample_id;
+};
+
+static enum bpf_perf_event_ret
+perf_buffer__process_record(struct perf_event_header *e, void *ctx)
+{
+	struct perf_cpu_buf *cpu_buf = ctx;
+	struct perf_buffer *pb = cpu_buf->pb;
+	void *data = e;
+
+	/* user wants full control over parsing perf event */
+	if (pb->event_cb)
+		return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
+
+	switch (e->type) {
+	case PERF_RECORD_SAMPLE: {
+		struct perf_sample_raw *s = data;
+
+		if (pb->sample_cb)
+			pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
+		break;
+	}
+	case PERF_RECORD_LOST: {
+		struct perf_sample_lost *s = data;
+
+		if (pb->lost_cb)
+			pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
+		break;
+	}
+	default:
+		pr_warn("unknown perf sample type %u\n", e->type);
+		return LIBBPF_PERF_EVENT_ERROR;
+	}
+	return LIBBPF_PERF_EVENT_CONT;
+}
+
+static int perf_buffer__process_records(struct perf_buffer *pb,
+					struct perf_cpu_buf *cpu_buf)
+{
+	enum bpf_perf_event_ret ret;
+
+	ret = perf_event_read_simple(cpu_buf->base, pb->mmap_size,
+				     pb->page_size, &cpu_buf->buf,
+				     &cpu_buf->buf_size,
+				     perf_buffer__process_record, cpu_buf);
+	if (ret != LIBBPF_PERF_EVENT_CONT)
+		return ret;
+	return 0;
+}
+
+int perf_buffer__epoll_fd(const struct perf_buffer *pb)
+{
+	return pb->epoll_fd;
+}
+
+int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
+{
+	int i, cnt, err;
+
+	cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
+	if (cnt < 0)
+		return -errno;
+
+	for (i = 0; i < cnt; i++) {
+		struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
+
+		err = perf_buffer__process_records(pb, cpu_buf);
+		if (err) {
+			pr_warn("error while processing records: %s\n", errstr(err));
+			return libbpf_err(err);
+		}
+	}
+	return cnt;
+}
+
+/* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer
+ * manager.
+ */
+size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb)
+{
+	return pb->cpu_cnt;
+}
+
+/*
+ * Return perf_event FD of a ring buffer in *buf_idx* slot of
+ * PERF_EVENT_ARRAY BPF map. This FD can be polled for new data using
+ * select()/poll()/epoll() Linux syscalls.
+ */
+int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx)
+{
+	struct perf_cpu_buf *cpu_buf;
+
+	if (buf_idx >= pb->cpu_cnt)
+		return libbpf_err(-EINVAL);
+
+	cpu_buf = pb->cpu_bufs[buf_idx];
+	if (!cpu_buf)
+		return libbpf_err(-ENOENT);
+
+	return cpu_buf->fd;
+}
+
+int perf_buffer__buffer(struct perf_buffer *pb, int buf_idx, void **buf, size_t *buf_size)
+{
+	struct perf_cpu_buf *cpu_buf;
+
+	if (buf_idx >= pb->cpu_cnt)
+		return libbpf_err(-EINVAL);
+
+	cpu_buf = pb->cpu_bufs[buf_idx];
+	if (!cpu_buf)
+		return libbpf_err(-ENOENT);
+
+	*buf = cpu_buf->base;
+	*buf_size = pb->mmap_size;
+	return 0;
+}
+
+/*
+ * Consume data from perf ring buffer corresponding to slot *buf_idx* in
+ * PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to
+ * consume, do nothing and return success.
+ * Returns:
+ *   - 0 on success;
+ *   - <0 on failure.
+ */
+int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx)
+{
+	struct perf_cpu_buf *cpu_buf;
+
+	if (buf_idx >= pb->cpu_cnt)
+		return libbpf_err(-EINVAL);
+
+	cpu_buf = pb->cpu_bufs[buf_idx];
+	if (!cpu_buf)
+		return libbpf_err(-ENOENT);
+
+	return perf_buffer__process_records(pb, cpu_buf);
+}
+
+int perf_buffer__consume(struct perf_buffer *pb)
+{
+	int i, err;
+
+	for (i = 0; i < pb->cpu_cnt; i++) {
+		struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
+
+		if (!cpu_buf)
+			continue;
+
+		err = perf_buffer__process_records(pb, cpu_buf);
+		if (err) {
+			pr_warn("perf_buffer: failed to process records in buffer #%d: %s\n",
+				i, errstr(err));
+			return libbpf_err(err);
+		}
+	}
+	return 0;
+}
+
+int bpf_program__set_attach_target(struct bpf_program *prog,
+				   int attach_prog_fd,
+				   const char *attach_func_name)
+{
+	int btf_obj_fd = 0, btf_id = 0, err;
+
+	if (!prog || attach_prog_fd < 0)
+		return libbpf_err(-EINVAL);
+
+	if (prog->obj->state >= OBJ_LOADED)
+		return libbpf_err(-EINVAL);
+
+	if (attach_prog_fd && !attach_func_name) {
+		/* Store attach_prog_fd. The BTF ID will be resolved later during
+		 * the normal object/program load phase.
+		 */
+		prog->attach_prog_fd = attach_prog_fd;
+		return 0;
+	}
+
+	if (attach_prog_fd) {
+		btf_id = libbpf_find_prog_btf_id(attach_func_name,
+						 attach_prog_fd, prog->obj->token_fd);
+		if (btf_id < 0)
+			return libbpf_err(btf_id);
+	} else {
+		if (!attach_func_name)
+			return libbpf_err(-EINVAL);
+
+		/* load btf_vmlinux, if not yet */
+		err = bpf_object__load_vmlinux_btf(prog->obj, true);
+		if (err)
+			return libbpf_err(err);
+		err = find_kernel_btf_id(prog->obj, attach_func_name,
+					 prog->expected_attach_type,
+					 &btf_obj_fd, &btf_id);
+		if (err)
+			return libbpf_err(err);
+	}
+
+	prog->attach_btf_id = btf_id;
+	prog->attach_btf_obj_fd = btf_obj_fd;
+	prog->attach_prog_fd = attach_prog_fd;
+	return 0;
+}
+
+int bpf_program__assoc_struct_ops(struct bpf_program *prog, struct bpf_map *map,
+				  struct bpf_prog_assoc_struct_ops_opts *opts)
+{
+	int prog_fd, map_fd;
+
+	prog_fd = bpf_program__fd(prog);
+	if (prog_fd < 0) {
+		pr_warn("prog '%s': can't associate BPF program without FD (was it loaded?)\n",
+			prog->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) {
+		pr_warn("prog '%s': can't associate struct_ops program\n", prog->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	map_fd = bpf_map__fd(map);
+	if (map_fd < 0) {
+		pr_warn("map '%s': can't associate BPF map without FD (was it created?)\n", map->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	if (!bpf_map__is_struct_ops(map)) {
+		pr_warn("map '%s': can't associate non-struct_ops map\n", map->name);
+		return libbpf_err(-EINVAL);
+	}
+
+	return bpf_prog_assoc_struct_ops(prog_fd, map_fd, opts);
+}
+
+int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
+{
+	int err = 0, n, len, start, end = -1;
+	bool *tmp;
+
+	*mask = NULL;
+	*mask_sz = 0;
+
+	/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
+	while (*s) {
+		if (*s == ',' || *s == '\n') {
+			s++;
+			continue;
+		}
+		n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len);
+		if (n <= 0 || n > 2) {
+			pr_warn("Failed to get CPU range %s: %d\n", s, n);
+			err = -EINVAL;
+			goto cleanup;
+		} else if (n == 1) {
+			end = start;
+		}
+		if (start < 0 || start > end) {
+			pr_warn("Invalid CPU range [%d,%d] in %s\n",
+				start, end, s);
+			err = -EINVAL;
+			goto cleanup;
+		}
+		tmp = realloc(*mask, end + 1);
+		if (!tmp) {
+			err = -ENOMEM;
+			goto cleanup;
+		}
+		*mask = tmp;
+		memset(tmp + *mask_sz, 0, start - *mask_sz);
+		memset(tmp + start, 1, end - start + 1);
+		*mask_sz = end + 1;
+		s += len;
+	}
+	if (!*mask_sz) {
+		pr_warn("Empty CPU range\n");
+		return -EINVAL;
+	}
+	return 0;
+cleanup:
+	free(*mask);
+	*mask = NULL;
+	return err;
+}
+
+int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
+{
+	int fd, err = 0, len;
+	char buf[128];
+
+	fd = open(fcpu, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		err = -errno;
+		pr_warn("Failed to open cpu mask file %s: %s\n", fcpu, errstr(err));
+		return err;
+	}
+	len = read(fd, buf, sizeof(buf));
+	close(fd);
+	if (len <= 0) {
+		err = len ? -errno : -EINVAL;
+		pr_warn("Failed to read cpu mask from %s: %s\n", fcpu, errstr(err));
+		return err;
+	}
+	if (len >= sizeof(buf)) {
+		pr_warn("CPU mask is too big in file %s\n", fcpu);
+		return -E2BIG;
+	}
+	buf[len] = '\0';
+
+	return parse_cpu_mask_str(buf, mask, mask_sz);
+}
+
+int libbpf_num_possible_cpus(void)
+{
+	static const char *fcpu = "/sys/devices/system/cpu/possible";
+	static int cpus;
+	int err, n, i, tmp_cpus;
+	bool *mask;
+
+	tmp_cpus = READ_ONCE(cpus);
+	if (tmp_cpus > 0)
+		return tmp_cpus;
+
+	err = parse_cpu_mask_file(fcpu, &mask, &n);
+	if (err)
+		return libbpf_err(err);
+
+	tmp_cpus = 0;
+	for (i = 0; i < n; i++) {
+		if (mask[i])
+			tmp_cpus++;
+	}
+	free(mask);
+
+	WRITE_ONCE(cpus, tmp_cpus);
+	return tmp_cpus;
+}
+
+static int populate_skeleton_maps(const struct bpf_object *obj,
+				  struct bpf_map_skeleton *maps,
+				  size_t map_cnt, size_t map_skel_sz)
+{
+	int i;
+
+	for (i = 0; i < map_cnt; i++) {
+		struct bpf_map_skeleton *map_skel = (void *)maps + i * map_skel_sz;
+		struct bpf_map **map = map_skel->map;
+		const char *name = map_skel->name;
+		void **mmaped = map_skel->mmaped;
+
+		*map = bpf_object__find_map_by_name(obj, name);
+		if (!*map) {
+			pr_warn("failed to find skeleton map '%s'\n", name);
+			return -ESRCH;
+		}
+
+		/* externs shouldn't be pre-setup from user code */
+		if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
+			*mmaped = (*map)->mmaped;
+	}
+	return 0;
+}
+
+static int populate_skeleton_progs(const struct bpf_object *obj,
+				   struct bpf_prog_skeleton *progs,
+				   size_t prog_cnt, size_t prog_skel_sz)
+{
+	int i;
+
+	for (i = 0; i < prog_cnt; i++) {
+		struct bpf_prog_skeleton *prog_skel = (void *)progs + i * prog_skel_sz;
+		struct bpf_program **prog = prog_skel->prog;
+		const char *name = prog_skel->name;
+
+		*prog = bpf_object__find_program_by_name(obj, name);
+		if (!*prog) {
+			pr_warn("failed to find skeleton program '%s'\n", name);
+			return -ESRCH;
+		}
+	}
+	return 0;
+}
+
+int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
+			      const struct bpf_object_open_opts *opts)
+{
+	struct bpf_object *obj;
+	int err;
+
+	obj = bpf_object_open(NULL, s->data, s->data_sz, s->name, opts);
+	if (IS_ERR(obj)) {
+		err = PTR_ERR(obj);
+		pr_warn("failed to initialize skeleton BPF object '%s': %s\n",
+			s->name, errstr(err));
+		return libbpf_err(err);
+	}
+
+	*s->obj = obj;
+	err = populate_skeleton_maps(obj, s->maps, s->map_cnt, s->map_skel_sz);
+	if (err) {
+		pr_warn("failed to populate skeleton maps for '%s': %s\n", s->name, errstr(err));
+		return libbpf_err(err);
+	}
+
+	err = populate_skeleton_progs(obj, s->progs, s->prog_cnt, s->prog_skel_sz);
+	if (err) {
+		pr_warn("failed to populate skeleton progs for '%s': %s\n", s->name, errstr(err));
+		return libbpf_err(err);
+	}
+
+	return 0;
+}
+
+int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s)
+{
+	int err, len, var_idx, i;
+	const char *var_name;
+	const struct bpf_map *map;
+	struct btf *btf;
+	__u32 map_type_id;
+	const struct btf_type *map_type, *var_type;
+	const struct bpf_var_skeleton *var_skel;
+	struct btf_var_secinfo *var;
+
+	if (!s->obj)
+		return libbpf_err(-EINVAL);
+
+	btf = bpf_object__btf(s->obj);
+	if (!btf) {
+		pr_warn("subskeletons require BTF at runtime (object %s)\n",
+			bpf_object__name(s->obj));
+		return libbpf_err(-errno);
+	}
+
+	err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt, s->map_skel_sz);
+	if (err) {
+		pr_warn("failed to populate subskeleton maps: %s\n", errstr(err));
+		return libbpf_err(err);
+	}
+
+	err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt, s->prog_skel_sz);
+	if (err) {
+		pr_warn("failed to populate subskeleton maps: %s\n", errstr(err));
+		return libbpf_err(err);
+	}
+
+	for (var_idx = 0; var_idx < s->var_cnt; var_idx++) {
+		var_skel = (void *)s->vars + var_idx * s->var_skel_sz;
+		map = *var_skel->map;
+		map_type_id = bpf_map__btf_value_type_id(map);
+		map_type = btf__type_by_id(btf, map_type_id);
+
+		if (!btf_is_datasec(map_type)) {
+			pr_warn("type for map '%1$s' is not a datasec: %2$s\n",
+				bpf_map__name(map),
+				__btf_kind_str(btf_kind(map_type)));
+			return libbpf_err(-EINVAL);
+		}
+
+		len = btf_vlen(map_type);
+		var = btf_var_secinfos(map_type);
+		for (i = 0; i < len; i++, var++) {
+			var_type = btf__type_by_id(btf, var->type);
+			var_name = btf__name_by_offset(btf, var_type->name_off);
+			if (strcmp(var_name, var_skel->name) == 0) {
+				*var_skel->addr = map->mmaped + var->offset;
+				break;
+			}
+		}
+	}
+	return 0;
+}
+
+void bpf_object__destroy_subskeleton(struct bpf_object_subskeleton *s)
+{
+	if (!s)
+		return;
+	free(s->maps);
+	free(s->progs);
+	free(s->vars);
+	free(s);
+}
+
+int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
+{
+	int i, err;
+
+	err = bpf_object__load(*s->obj);
+	if (err) {
+		pr_warn("failed to load BPF skeleton '%s': %s\n", s->name, errstr(err));
+		return libbpf_err(err);
+	}
+
+	for (i = 0; i < s->map_cnt; i++) {
+		struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz;
+		struct bpf_map *map = *map_skel->map;
+
+		if (!map_skel->mmaped)
+			continue;
+
+		if (map->def.type == BPF_MAP_TYPE_ARENA)
+			*map_skel->mmaped = map->mmaped + map->obj->arena_data_off;
+		else
+			*map_skel->mmaped = map->mmaped;
+	}
+
+	return 0;
+}
+
+int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
+{
+	int i, err;
+
+	for (i = 0; i < s->prog_cnt; i++) {
+		struct bpf_prog_skeleton *prog_skel = (void *)s->progs + i * s->prog_skel_sz;
+		struct bpf_program *prog = *prog_skel->prog;
+		struct bpf_link **link = prog_skel->link;
+
+		if (!prog->autoload || !prog->autoattach)
+			continue;
+
+		/* auto-attaching not supported for this program */
+		if (!prog->sec_def || !prog->sec_def->prog_attach_fn)
+			continue;
+
+		/* if user already set the link manually, don't attempt auto-attach */
+		if (*link)
+			continue;
+
+		err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, link);
+		if (err) {
+			pr_warn("prog '%s': failed to auto-attach: %s\n",
+				bpf_program__name(prog), errstr(err));
+			return libbpf_err(err);
+		}
+
+		/* It's possible that for some SEC() definitions auto-attach
+		 * is supported in some cases (e.g., if definition completely
+		 * specifies target information), but is not in other cases.
+		 * SEC("uprobe") is one such case. If user specified target
+		 * binary and function name, such BPF program can be
+		 * auto-attached. But if not, it shouldn't trigger skeleton's
+		 * attach to fail. It should just be skipped.
+		 * attach_fn signals such case with returning 0 (no error) and
+		 * setting link to NULL.
+		 */
+	}
+
+
+	for (i = 0; i < s->map_cnt; i++) {
+		struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz;
+		struct bpf_map *map = *map_skel->map;
+		struct bpf_link **link;
+
+		if (!map->autocreate || !map->autoattach)
+			continue;
+
+		/* only struct_ops maps can be attached */
+		if (!bpf_map__is_struct_ops(map))
+			continue;
+
+		/* skeleton is created with earlier version of bpftool, notify user */
+		if (s->map_skel_sz < offsetofend(struct bpf_map_skeleton, link)) {
+			pr_warn("map '%s': BPF skeleton version is old, skipping map auto-attachment...\n",
+				bpf_map__name(map));
+			continue;
+		}
+
+		link = map_skel->link;
+		if (!link) {
+			pr_warn("map '%s': BPF map skeleton link is uninitialized\n",
+				bpf_map__name(map));
+			continue;
+		}
+
+		if (*link)
+			continue;
+
+		*link = bpf_map__attach_struct_ops(map);
+		if (!*link) {
+			err = -errno;
+			pr_warn("map '%s': failed to auto-attach: %s\n",
+				bpf_map__name(map), errstr(err));
+			return libbpf_err(err);
+		}
+	}
+
+	return 0;
+}
+
+void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
+{
+	int i;
+
+	for (i = 0; i < s->prog_cnt; i++) {
+		struct bpf_prog_skeleton *prog_skel = (void *)s->progs + i * s->prog_skel_sz;
+		struct bpf_link **link = prog_skel->link;
+
+		bpf_link__destroy(*link);
+		*link = NULL;
+	}
+
+	if (s->map_skel_sz < sizeof(struct bpf_map_skeleton))
+		return;
+
+	for (i = 0; i < s->map_cnt; i++) {
+		struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz;
+		struct bpf_link **link = map_skel->link;
+
+		if (link) {
+			bpf_link__destroy(*link);
+			*link = NULL;
+		}
+	}
+}
+
+void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
+{
+	if (!s)
+		return;
+
+	bpf_object__detach_skeleton(s);
+	if (s->obj)
+		bpf_object__close(*s->obj);
+	free(s->maps);
+	free(s->progs);
+	free(s);
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
new file mode 100644
index 000000000..b965ad571
--- /dev/null
+++ b/tools/lib/bpf/libbpf.h
@@ -0,0 +1,2085 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * Common eBPF ELF object loading operations.
+ *
+ * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ */
+#ifndef __LIBBPF_LIBBPF_H
+#define __LIBBPF_LIBBPF_H
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/types.h>  // for size_t
+#include <linux/bpf.h>
+
+#include "libbpf_common.h"
+#include "libbpf_legacy.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief **libbpf_major_version()** provides the major version of libbpf.
+ * @return An integer, the major version number
+ */
+LIBBPF_API __u32 libbpf_major_version(void);
+
+/**
+ * @brief **libbpf_minor_version()** provides the minor version of libbpf.
+ * @return An integer, the minor version number
+ */
+LIBBPF_API __u32 libbpf_minor_version(void);
+
+/**
+ * @brief **libbpf_version_string()** provides the version of libbpf in a
+ * human-readable form, e.g., "v1.7".
+ * @return Pointer to a static string containing the version
+ *
+ * The format is *not* a part of a stable API and may change in the future.
+ */
+LIBBPF_API const char *libbpf_version_string(void);
+
+enum libbpf_errno {
+	__LIBBPF_ERRNO__START = 4000,
+
+	/* Something wrong in libelf */
+	LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START,
+	LIBBPF_ERRNO__FORMAT,	/* BPF object format invalid */
+	LIBBPF_ERRNO__KVERSION,	/* Incorrect or no 'version' section */
+	LIBBPF_ERRNO__ENDIAN,	/* Endian mismatch */
+	LIBBPF_ERRNO__INTERNAL,	/* Internal error in libbpf */
+	LIBBPF_ERRNO__RELOC,	/* Relocation failed */
+	LIBBPF_ERRNO__LOAD,	/* Load program failure for unknown reason */
+	LIBBPF_ERRNO__VERIFY,	/* Kernel verifier blocks program loading */
+	LIBBPF_ERRNO__PROG2BIG,	/* Program too big */
+	LIBBPF_ERRNO__KVER,	/* Incorrect kernel version */
+	LIBBPF_ERRNO__PROGTYPE,	/* Kernel doesn't support this program type */
+	LIBBPF_ERRNO__WRNGPID,	/* Wrong pid in netlink message */
+	LIBBPF_ERRNO__INVSEQ,	/* Invalid netlink sequence */
+	LIBBPF_ERRNO__NLPARSE,	/* netlink parsing error */
+	__LIBBPF_ERRNO__END,
+};
+
+/**
+ * @brief **libbpf_strerror()** converts the provided error code into a
+ * human-readable string.
+ * @param err The error code to convert
+ * @param buf Pointer to a buffer where the error message will be stored
+ * @param size The number of bytes in the buffer
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size);
+
+/**
+ * @brief **libbpf_bpf_attach_type_str()** converts the provided attach type
+ * value into a textual representation.
+ * @param t The attach type.
+ * @return Pointer to a static string identifying the attach type. NULL is
+ * returned for unknown **bpf_attach_type** values.
+ */
+LIBBPF_API const char *libbpf_bpf_attach_type_str(enum bpf_attach_type t);
+
+/**
+ * @brief **libbpf_bpf_link_type_str()** converts the provided link type value
+ * into a textual representation.
+ * @param t The link type.
+ * @return Pointer to a static string identifying the link type. NULL is
+ * returned for unknown **bpf_link_type** values.
+ */
+LIBBPF_API const char *libbpf_bpf_link_type_str(enum bpf_link_type t);
+
+/**
+ * @brief **libbpf_bpf_map_type_str()** converts the provided map type value
+ * into a textual representation.
+ * @param t The map type.
+ * @return Pointer to a static string identifying the map type. NULL is
+ * returned for unknown **bpf_map_type** values.
+ */
+LIBBPF_API const char *libbpf_bpf_map_type_str(enum bpf_map_type t);
+
+/**
+ * @brief **libbpf_bpf_prog_type_str()** converts the provided program type
+ * value into a textual representation.
+ * @param t The program type.
+ * @return Pointer to a static string identifying the program type. NULL is
+ * returned for unknown **bpf_prog_type** values.
+ */
+LIBBPF_API const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t);
+
+enum libbpf_print_level {
+        LIBBPF_WARN,
+        LIBBPF_INFO,
+        LIBBPF_DEBUG,
+};
+
+typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level,
+				 const char *, va_list ap);
+
+/**
+ * @brief **libbpf_set_print()** sets user-provided log callback function to
+ * be used for libbpf warnings and informational messages. If the user callback
+ * is not set, messages are logged to stderr by default. The verbosity of these
+ * messages can be controlled by setting the environment variable
+ * LIBBPF_LOG_LEVEL to either warn, info, or debug.
+ * @param fn The log print function. If NULL, libbpf won't print anything.
+ * @return Pointer to old print function.
+ *
+ * This function is thread-safe.
+ */
+LIBBPF_API libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn);
+
+/* Hide internal to user */
+struct bpf_object;
+
+struct bpf_object_open_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* object name override, if provided:
+	 * - for object open from file, this will override setting object
+	 *   name from file path's base name;
+	 * - for object open from memory buffer, this will specify an object
+	 *   name and will override default "<addr>-<buf-size>" name;
+	 */
+	const char *object_name;
+	/* parse map definitions non-strictly, allowing extra attributes/data */
+	bool relaxed_maps;
+	/* maps that set the 'pinning' attribute in their definition will have
+	 * their pin_path attribute set to a file in this directory, and be
+	 * auto-pinned to that path on load; defaults to "/sys/fs/bpf".
+	 */
+	const char *pin_root_path;
+
+	__u32 :32; /* stub out now removed attach_prog_fd */
+
+	/* Additional kernel config content that augments and overrides
+	 * system Kconfig for CONFIG_xxx externs.
+	 */
+	const char *kconfig;
+	/* Path to the custom BTF to be used for BPF CO-RE relocations.
+	 * This custom BTF completely replaces the use of vmlinux BTF
+	 * for the purpose of CO-RE relocations.
+	 * NOTE: any other BPF feature (e.g., fentry/fexit programs,
+	 * struct_ops, etc) will need actual kernel BTF at /sys/kernel/btf/vmlinux.
+	 */
+	const char *btf_custom_path;
+	/* Pointer to a buffer for storing kernel logs for applicable BPF
+	 * commands. Valid kernel_log_size has to be specified as well and are
+	 * passed-through to bpf() syscall. Keep in mind that kernel might
+	 * fail operation with -ENOSPC error if provided buffer is too small
+	 * to contain entire log output.
+	 * See the comment below for kernel_log_level for interaction between
+	 * log_buf and log_level settings.
+	 *
+	 * If specified, this log buffer will be passed for:
+	 *   - each BPF progral load (BPF_PROG_LOAD) attempt, unless overridden
+	 *     with bpf_program__set_log() on per-program level, to get
+	 *     BPF verifier log output.
+	 *   - during BPF object's BTF load into kernel (BPF_BTF_LOAD) to get
+	 *     BTF sanity checking log.
+	 *
+	 * Each BPF command (BPF_BTF_LOAD or BPF_PROG_LOAD) will overwrite
+	 * previous contents, so if you need more fine-grained control, set
+	 * per-program buffer with bpf_program__set_log_buf() to preserve each
+	 * individual program's verification log. Keep using kernel_log_buf
+	 * for BTF verification log, if necessary.
+	 */
+	char *kernel_log_buf;
+	size_t kernel_log_size;
+	/*
+	 * Log level can be set independently from log buffer. Log_level=0
+	 * means that libbpf will attempt loading BTF or program without any
+	 * logging requested, but will retry with either its own or custom log
+	 * buffer, if provided, and log_level=1 on any error.
+	 * And vice versa, setting log_level>0 will request BTF or prog
+	 * loading with verbose log from the first attempt (and as such also
+	 * for successfully loaded BTF or program), and the actual log buffer
+	 * could be either libbpf's own auto-allocated log buffer, if
+	 * kernel_log_buffer is NULL, or user-provided custom kernel_log_buf.
+	 * If user didn't provide custom log buffer, libbpf will emit captured
+	 * logs through its print callback.
+	 */
+	__u32 kernel_log_level;
+	/* Path to BPF FS mount point to derive BPF token from.
+	 *
+	 * Created BPF token will be used for all bpf() syscall operations
+	 * that accept BPF token (e.g., map creation, BTF and program loads,
+	 * etc) automatically within instantiated BPF object.
+	 *
+	 * If bpf_token_path is not specified, libbpf will consult
+	 * LIBBPF_BPF_TOKEN_PATH environment variable. If set, it will be
+	 * taken as a value of bpf_token_path option and will force libbpf to
+	 * either create BPF token from provided custom BPF FS path, or will
+	 * disable implicit BPF token creation, if envvar value is an empty
+	 * string. bpf_token_path overrides LIBBPF_BPF_TOKEN_PATH, if both are
+	 * set at the same time.
+	 *
+	 * Setting bpf_token_path option to empty string disables libbpf's
+	 * automatic attempt to create BPF token from default BPF FS mount
+	 * point (/sys/fs/bpf), in case this default behavior is undesirable.
+	 */
+	const char *bpf_token_path;
+
+	size_t :0;
+};
+#define bpf_object_open_opts__last_field bpf_token_path
+
+/**
+ * @brief **bpf_object__open()** creates a bpf_object by opening
+ * the BPF ELF object file pointed to by the passed path and loading it
+ * into memory.
+ * @param path BPF object file path.
+ * @return pointer to the new bpf_object; or NULL is returned on error,
+ * error code is stored in errno
+ */
+LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
+
+/**
+ * @brief **bpf_object__open_file()** creates a bpf_object by opening
+ * the BPF ELF object file pointed to by the passed path and loading it
+ * into memory.
+ * @param path BPF object file path
+ * @param opts options for how to load the bpf object, this parameter is
+ * optional and can be set to NULL
+ * @return pointer to the new bpf_object; or NULL is returned on error,
+ * error code is stored in errno
+ */
+LIBBPF_API struct bpf_object *
+bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts);
+
+/**
+ * @brief **bpf_object__open_mem()** creates a bpf_object by reading
+ * the BPF objects raw bytes from a memory buffer containing a valid
+ * BPF ELF object file.
+ * @param obj_buf pointer to the buffer containing ELF file bytes
+ * @param obj_buf_sz number of bytes in the buffer
+ * @param opts options for how to load the bpf object
+ * @return pointer to the new bpf_object; or NULL is returned on error,
+ * error code is stored in errno
+ */
+LIBBPF_API struct bpf_object *
+bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
+		     const struct bpf_object_open_opts *opts);
+
+/**
+ * @brief **bpf_object__prepare()** prepares BPF object for loading:
+ * performs ELF processing, relocations, prepares final state of BPF program
+ * instructions (accessible with bpf_program__insns()), creates and
+ * (potentially) pins maps. Leaves BPF object in the state ready for program
+ * loading.
+ * @param obj Pointer to a valid BPF object instance returned by
+ * **bpf_object__open*()** API
+ * @return 0, on success; negative error code, otherwise, error code is
+ * stored in errno
+ */
+LIBBPF_API int bpf_object__prepare(struct bpf_object *obj);
+
+/**
+ * @brief **bpf_object__load()** loads BPF object into kernel.
+ * @param obj Pointer to a valid BPF object instance returned by
+ * **bpf_object__open*()** APIs
+ * @return 0, on success; negative error code, otherwise, error code is
+ * stored in errno
+ */
+LIBBPF_API int bpf_object__load(struct bpf_object *obj);
+
+/**
+ * @brief **bpf_object__close()** closes a BPF object and releases all
+ * resources.
+ * @param obj Pointer to a valid BPF object
+ */
+LIBBPF_API void bpf_object__close(struct bpf_object *obj);
+
+/**
+ * @brief **bpf_object__pin_maps()** pins each map contained within
+ * the BPF object at the passed directory.
+ * @param obj Pointer to a valid BPF object
+ * @param path A directory where maps should be pinned.
+ * @return 0, on success; negative error code, otherwise
+ *
+ * If `path` is NULL `bpf_map__pin` (which is being used on each map)
+ * will use the pin_path attribute of each map. In this case, maps that
+ * don't have a pin_path set will be ignored.
+ */
+LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
+
+/**
+ * @brief **bpf_object__unpin_maps()** unpins each map contained within
+ * the BPF object found in the passed directory.
+ * @param obj Pointer to a valid BPF object
+ * @param path A directory where pinned maps should be searched for.
+ * @return 0, on success; negative error code, otherwise
+ *
+ * If `path` is NULL `bpf_map__unpin` (which is being used on each map)
+ * will use the pin_path attribute of each map. In this case, maps that
+ * don't have a pin_path set will be ignored.
+ */
+LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
+				      const char *path);
+LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj,
+					const char *path);
+LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
+					  const char *path);
+LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
+LIBBPF_API int bpf_object__unpin(struct bpf_object *object, const char *path);
+
+LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);
+LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);
+LIBBPF_API int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version);
+
+/**
+ * @brief **bpf_object__token_fd** is an accessor for BPF token FD associated
+ * with BPF object.
+ * @param obj Pointer to a valid BPF object
+ * @return BPF token FD or -1, if it wasn't set
+ */
+LIBBPF_API int bpf_object__token_fd(const struct bpf_object *obj);
+
+struct btf;
+LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj);
+LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
+
+LIBBPF_API struct bpf_program *
+bpf_object__find_program_by_name(const struct bpf_object *obj,
+				 const char *name);
+
+LIBBPF_API int
+libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+			 enum bpf_attach_type *expected_attach_type);
+LIBBPF_API int libbpf_attach_type_by_name(const char *name,
+					  enum bpf_attach_type *attach_type);
+LIBBPF_API int libbpf_find_vmlinux_btf_id(const char *name,
+					  enum bpf_attach_type attach_type);
+
+/* Accessors of bpf_program */
+struct bpf_program;
+
+LIBBPF_API struct bpf_program *
+bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prog);
+
+#define bpf_object__for_each_program(pos, obj)			\
+	for ((pos) = bpf_object__next_program((obj), NULL);	\
+	     (pos) != NULL;					\
+	     (pos) = bpf_object__next_program((obj), (pos)))
+
+LIBBPF_API struct bpf_program *
+bpf_object__prev_program(const struct bpf_object *obj, struct bpf_program *prog);
+
+LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,
+					 __u32 ifindex);
+
+LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog);
+LIBBPF_API const char *bpf_program__section_name(const struct bpf_program *prog);
+LIBBPF_API bool bpf_program__autoload(const struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_autoload(struct bpf_program *prog, bool autoload);
+LIBBPF_API bool bpf_program__autoattach(const struct bpf_program *prog);
+LIBBPF_API void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach);
+
+struct bpf_insn;
+
+/**
+ * @brief **bpf_program__insns()** gives read-only access to BPF program's
+ * underlying BPF instructions.
+ * @param prog BPF program for which to return instructions
+ * @return a pointer to an array of BPF instructions that belong to the
+ * specified BPF program
+ *
+ * Returned pointer is always valid and not NULL. Number of `struct bpf_insn`
+ * pointed to can be fetched using **bpf_program__insn_cnt()** API.
+ *
+ * Keep in mind, libbpf can modify and append/delete BPF program's
+ * instructions as it processes BPF object file and prepares everything for
+ * uploading into the kernel. So depending on the point in BPF object
+ * lifetime, **bpf_program__insns()** can return different sets of
+ * instructions. As an example, during BPF object load phase BPF program
+ * instructions will be CO-RE-relocated, BPF subprograms instructions will be
+ * appended, ldimm64 instructions will have FDs embedded, etc. So instructions
+ * returned before **bpf_object__load()** and after it might be quite
+ * different.
+ */
+LIBBPF_API const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_insns()** can set BPF program's underlying
+ * BPF instructions.
+ *
+ * WARNING: This is a very advanced libbpf API and users need to know
+ * what they are doing. This should be used from prog_prepare_load_fn
+ * callback only.
+ *
+ * @param prog BPF program for which to return instructions
+ * @param new_insns a pointer to an array of BPF instructions
+ * @param new_insn_cnt number of `struct bpf_insn`'s that form
+ * specified BPF program
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int bpf_program__set_insns(struct bpf_program *prog,
+				      struct bpf_insn *new_insns, size_t new_insn_cnt);
+
+/**
+ * @brief **bpf_program__insn_cnt()** returns number of `struct bpf_insn`'s
+ * that form specified BPF program.
+ * @param prog BPF program for which to return number of BPF instructions
+ *
+ * See **bpf_program__insns()** documentation for notes on how libbpf can
+ * change instructions and their count during different phases of
+ * **bpf_object** lifetime.
+ */
+LIBBPF_API size_t bpf_program__insn_cnt(const struct bpf_program *prog);
+
+LIBBPF_API int bpf_program__fd(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__pin()** pins the BPF program to a file
+ * in the BPF FS specified by a path. This increments the programs
+ * reference count, allowing it to stay loaded after the process
+ * which loaded it has exited.
+ *
+ * @param prog BPF program to pin, must already be loaded
+ * @param path file path in a BPF file system
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int bpf_program__pin(struct bpf_program *prog, const char *path);
+
+/**
+ * @brief **bpf_program__unpin()** unpins the BPF program from a file
+ * in the BPFFS specified by a path. This decrements program's in-kernel
+ * reference count.
+ *
+ * The file pinning the BPF program can also be unlinked by a different
+ * process in which case this function will return an error.
+ *
+ * @param prog BPF program to unpin
+ * @param path file path to the pin in a BPF file system
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int bpf_program__unpin(struct bpf_program *prog, const char *path);
+LIBBPF_API void bpf_program__unload(struct bpf_program *prog);
+
+struct bpf_link;
+
+LIBBPF_API struct bpf_link *bpf_link__open(const char *path);
+LIBBPF_API int bpf_link__fd(const struct bpf_link *link);
+LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link);
+/**
+ * @brief **bpf_link__pin()** pins the BPF link to a file
+ * in the BPF FS specified by a path. This increments the links
+ * reference count, allowing it to stay loaded after the process
+ * which loaded it has exited.
+ *
+ * @param link BPF link to pin, must already be loaded
+ * @param path file path in a BPF file system
+ * @return 0, on success; negative error code, otherwise
+ */
+
+LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path);
+
+/**
+ * @brief **bpf_link__unpin()** unpins the BPF link from a file
+ * in the BPFFS. This decrements link's in-kernel reference count.
+ *
+ * The file pinning the BPF link can also be unlinked by a different
+ * process in which case this function will return an error.
+ *
+ * @param link BPF link to unpin
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int bpf_link__unpin(struct bpf_link *link);
+LIBBPF_API int bpf_link__update_program(struct bpf_link *link,
+					struct bpf_program *prog);
+LIBBPF_API void bpf_link__disconnect(struct bpf_link *link);
+LIBBPF_API int bpf_link__detach(struct bpf_link *link);
+LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
+
+/**
+ * @brief **bpf_program__attach()** is a generic function for attaching
+ * a BPF program based on auto-detection of program type, attach type,
+ * and extra parameters, where applicable.
+ *
+ * @param prog BPF program to attach
+ * @return Reference to the newly created BPF link; or NULL is returned on error,
+ * error code is stored in errno
+ *
+ * This is supported for:
+ *   - kprobe/kretprobe (depends on SEC() definition)
+ *   - uprobe/uretprobe (depends on SEC() definition)
+ *   - tracepoint
+ *   - raw tracepoint
+ *   - tracing programs (typed raw TP/fentry/fexit/fmod_ret)
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach(const struct bpf_program *prog);
+
+struct bpf_perf_event_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 bpf_cookie;
+	/* don't use BPF link when attach BPF program */
+	bool force_ioctl_attach;
+	/* don't automatically enable the event */
+	bool dont_enable;
+	size_t :0;
+};
+#define bpf_perf_event_opts__last_field dont_enable
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd);
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd,
+				    const struct bpf_perf_event_opts *opts);
+
+/**
+ * enum probe_attach_mode - the mode to attach kprobe/uprobe
+ *
+ * force libbpf to attach kprobe/uprobe in specific mode, -ENOTSUP will
+ * be returned if it is not supported by the kernel.
+ */
+enum probe_attach_mode {
+	/* attach probe in latest supported mode by kernel */
+	PROBE_ATTACH_MODE_DEFAULT = 0,
+	/* attach probe in legacy mode, using debugfs/tracefs */
+	PROBE_ATTACH_MODE_LEGACY,
+	/* create perf event with perf_event_open() syscall */
+	PROBE_ATTACH_MODE_PERF,
+	/* attach probe with BPF link */
+	PROBE_ATTACH_MODE_LINK,
+};
+
+struct bpf_kprobe_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 bpf_cookie;
+	/* function offset, or raw address if func_name == NULL */
+	size_t offset;
+	/* kprobe is return probe */
+	bool retprobe;
+	/* kprobe attach mode */
+	enum probe_attach_mode attach_mode;
+	size_t :0;
+};
+
+#define bpf_kprobe_opts__last_field attach_mode
+
+/**
+ * @brief **bpf_program__attach_kprobe()** attaches a BPF program to a
+ * kernel function entry or return.
+ *
+ * @param prog BPF program to attach
+ * @param retprobe Attach to function return
+ * @param func_name Name of the kernel function to attach to
+ * @return Reference to the newly created BPF link; or NULL is returned on
+ * error, error code is stored in errno
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe,
+			   const char *func_name);
+
+/**
+ * @brief **bpf_program__attach_kprobe_opts()** is just like
+ * bpf_program__attach_kprobe() except with an options struct
+ * for various configurations.
+ *
+ * @param prog BPF program to attach
+ * @param func_name Name of the kernel function to attach to. If NULL,
+ * opts->offset is treated as a raw kernel address. Raw-address attach
+ * is supported with PROBE_ATTACH_MODE_PERF and PROBE_ATTACH_MODE_LINK.
+ * @param opts Options for altering program attachment
+ * @return Reference to the newly created BPF link; or NULL is returned on
+ * error, error code is stored in errno
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
+                                const char *func_name,
+                                const struct bpf_kprobe_opts *opts);
+
+struct bpf_kprobe_multi_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* array of function symbols to attach */
+	const char **syms;
+	/* array of function addresses to attach */
+	const unsigned long *addrs;
+	/* array of user-provided values fetchable through bpf_get_attach_cookie */
+	const __u64 *cookies;
+	/* number of elements in syms/addrs/cookies arrays */
+	size_t cnt;
+	/* create return kprobes */
+	bool retprobe;
+	/* create session kprobes */
+	bool session;
+	/* enforce unique match */
+	bool unique_match;
+	size_t :0;
+};
+
+#define bpf_kprobe_multi_opts__last_field unique_match
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
+				      const char *pattern,
+				      const struct bpf_kprobe_multi_opts *opts);
+
+struct bpf_uprobe_multi_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* array of function symbols to attach to */
+	const char **syms;
+	/* array of function addresses to attach to */
+	const unsigned long *offsets;
+	/* optional, array of associated ref counter offsets */
+	const unsigned long *ref_ctr_offsets;
+	/* optional, array of associated BPF cookies */
+	const __u64 *cookies;
+	/* number of elements in syms/addrs/cookies arrays */
+	size_t cnt;
+	/* create return uprobes */
+	bool retprobe;
+	/* create session kprobes */
+	bool session;
+	size_t :0;
+};
+
+#define bpf_uprobe_multi_opts__last_field session
+
+/**
+ * @brief **bpf_program__attach_uprobe_multi()** attaches a BPF program
+ * to multiple uprobes with uprobe_multi link.
+ *
+ * User can specify 2 mutually exclusive set of inputs:
+ *
+ *   1) use only path/func_pattern/pid arguments
+ *
+ *   2) use path/pid with allowed combinations of
+ *      syms/offsets/ref_ctr_offsets/cookies/cnt
+ *
+ *      - syms and offsets are mutually exclusive
+ *      - ref_ctr_offsets and cookies are optional
+ *
+ *
+ * @param prog BPF program to attach
+ * @param pid Process ID to attach the uprobe to, 0 for self (own process),
+ * -1 for all processes
+ * @param binary_path Path to binary
+ * @param func_pattern Regular expression to specify functions to attach
+ * BPF program to
+ * @param opts Additional options (see **struct bpf_uprobe_multi_opts**)
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
+				 pid_t pid,
+				 const char *binary_path,
+				 const char *func_pattern,
+				 const struct bpf_uprobe_multi_opts *opts);
+
+struct bpf_ksyscall_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 bpf_cookie;
+	/* attach as return probe? */
+	bool retprobe;
+	size_t :0;
+};
+#define bpf_ksyscall_opts__last_field retprobe
+
+/**
+ * @brief **bpf_program__attach_ksyscall()** attaches a BPF program
+ * to kernel syscall handler of a specified syscall. Optionally it's possible
+ * to request to install retprobe that will be triggered at syscall exit. It's
+ * also possible to associate BPF cookie (though options).
+ *
+ * Libbpf automatically will determine correct full kernel function name,
+ * which depending on system architecture and kernel version/configuration
+ * could be of the form __<arch>_sys_<syscall> or __se_sys_<syscall>, and will
+ * attach specified program using kprobe/kretprobe mechanism.
+ *
+ * **bpf_program__attach_ksyscall()** is an API counterpart of declarative
+ * **SEC("ksyscall/<syscall>")** annotation of BPF programs.
+ *
+ * At the moment **SEC("ksyscall")** and **bpf_program__attach_ksyscall()** do
+ * not handle all the calling convention quirks for mmap(), clone() and compat
+ * syscalls. It also only attaches to "native" syscall interfaces. If host
+ * system supports compat syscalls or defines 32-bit syscalls in 64-bit
+ * kernel, such syscall interfaces won't be attached to by libbpf.
+ *
+ * These limitations may or may not change in the future. Therefore it is
+ * recommended to use SEC("kprobe") for these syscalls or if working with
+ * compat and 32-bit interfaces is required.
+ *
+ * @param prog BPF program to attach
+ * @param syscall_name Symbolic name of the syscall (e.g., "bpf")
+ * @param opts Additional options (see **struct bpf_ksyscall_opts**)
+ * @return Reference to the newly created BPF link; or NULL is returned on
+ * error, error code is stored in errno
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_ksyscall(const struct bpf_program *prog,
+			     const char *syscall_name,
+			     const struct bpf_ksyscall_opts *opts);
+
+struct bpf_tracing_multi_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	const __u32 *ids;
+	const __u64 *cookies;
+	size_t cnt;
+	size_t :0;
+};
+
+#define bpf_tracing_multi_opts__last_field cnt
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tracing_multi(const struct bpf_program *prog, const char *pattern,
+				  const struct bpf_tracing_multi_opts *opts);
+
+struct bpf_uprobe_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* offset of kernel reference counted USDT semaphore, added in
+	 * a6ca88b241d5 ("trace_uprobe: support reference counter in fd-based uprobe")
+	 */
+	size_t ref_ctr_offset;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 bpf_cookie;
+	/* uprobe is return probe, invoked at function return time */
+	bool retprobe;
+	/* Function name to attach to.  Could be an unqualified ("abc") or library-qualified
+	 * "abc@LIBXYZ" name.  To specify function entry, func_name should be set while
+	 * func_offset argument to bpf_prog__attach_uprobe_opts() should be 0.  To trace an
+	 * offset within a function, specify func_name and use func_offset argument to specify
+	 * offset within the function.  Shared library functions must specify the shared library
+	 * binary_path.
+	 */
+	const char *func_name;
+	/* uprobe attach mode */
+	enum probe_attach_mode attach_mode;
+	size_t :0;
+};
+#define bpf_uprobe_opts__last_field attach_mode
+
+/**
+ * @brief **bpf_program__attach_uprobe()** attaches a BPF program
+ * to the userspace function which is found by binary path and
+ * offset. You can optionally specify a particular process to attach
+ * to. You can also optionally attach the program to the function
+ * exit instead of entry.
+ *
+ * @param prog BPF program to attach
+ * @param retprobe Attach to function exit
+ * @param pid Process ID to attach the uprobe to, 0 for self (own process),
+ * -1 for all processes
+ * @param binary_path Path to binary that contains the function symbol
+ * @param func_offset Offset within the binary of the function symbol
+ * @return Reference to the newly created BPF link; or NULL is returned on error,
+ * error code is stored in errno
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_uprobe(const struct bpf_program *prog, bool retprobe,
+			   pid_t pid, const char *binary_path,
+			   size_t func_offset);
+
+/**
+ * @brief **bpf_program__attach_uprobe_opts()** is just like
+ * bpf_program__attach_uprobe() except with a options struct
+ * for various configurations.
+ *
+ * @param prog BPF program to attach
+ * @param pid Process ID to attach the uprobe to, 0 for self (own process),
+ * -1 for all processes
+ * @param binary_path Path to binary that contains the function symbol
+ * @param func_offset Offset within the binary of the function symbol
+ * @param opts Options for altering program attachment
+ * @return Reference to the newly created BPF link; or NULL is returned on error,
+ * error code is stored in errno
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
+				const char *binary_path, size_t func_offset,
+				const struct bpf_uprobe_opts *opts);
+
+struct bpf_usdt_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value accessible through usdt_cookie() */
+	__u64 usdt_cookie;
+	size_t :0;
+};
+#define bpf_usdt_opts__last_field usdt_cookie
+
+/**
+ * @brief **bpf_program__attach_usdt()** is just like
+ * bpf_program__attach_uprobe_opts() except it covers USDT (User-space
+ * Statically Defined Tracepoint) attachment, instead of attaching to
+ * user-space function entry or exit.
+ *
+ * @param prog BPF program to attach
+ * @param pid Process ID to attach the uprobe to, 0 for self (own process),
+ * -1 for all processes
+ * @param binary_path Path to binary that contains provided USDT probe
+ * @param usdt_provider USDT provider name
+ * @param usdt_name USDT probe name
+ * @param opts Options for altering program attachment
+ * @return Reference to the newly created BPF link; or NULL is returned on error,
+ * error code is stored in errno
+ */
+LIBBPF_API struct bpf_link *
+bpf_program__attach_usdt(const struct bpf_program *prog,
+			 pid_t pid, const char *binary_path,
+			 const char *usdt_provider, const char *usdt_name,
+			 const struct bpf_usdt_opts *opts);
+
+struct bpf_tracepoint_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 bpf_cookie;
+};
+#define bpf_tracepoint_opts__last_field bpf_cookie
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tracepoint(const struct bpf_program *prog,
+			       const char *tp_category,
+			       const char *tp_name);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
+				    const char *tp_category,
+				    const char *tp_name,
+				    const struct bpf_tracepoint_opts *opts);
+
+struct bpf_raw_tracepoint_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	__u64 cookie;
+	size_t :0;
+};
+#define bpf_raw_tracepoint_opts__last_field cookie
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
+				   const char *tp_name);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_raw_tracepoint_opts(const struct bpf_program *prog,
+					const char *tp_name,
+					struct bpf_raw_tracepoint_opts *opts);
+
+struct bpf_trace_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
+	__u64 cookie;
+};
+#define bpf_trace_opts__last_field cookie
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_trace(const struct bpf_program *prog);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_trace_opts(const struct bpf_program *prog, const struct bpf_trace_opts *opts);
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_lsm(const struct bpf_program *prog);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_sockmap(const struct bpf_program *prog, int map_fd);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex);
+LIBBPF_API struct bpf_link *
+bpf_program__attach_freplace(const struct bpf_program *prog,
+			     int target_fd, const char *attach_func_name);
+
+struct bpf_netfilter_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+
+	__u32 pf;
+	__u32 hooknum;
+	__s32 priority;
+	__u32 flags;
+};
+#define bpf_netfilter_opts__last_field flags
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_netfilter(const struct bpf_program *prog,
+			      const struct bpf_netfilter_opts *opts);
+
+struct bpf_tcx_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	__u32 flags;
+	__u32 relative_fd;
+	__u32 relative_id;
+	__u64 expected_revision;
+	size_t :0;
+};
+#define bpf_tcx_opts__last_field expected_revision
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,
+			const struct bpf_tcx_opts *opts);
+
+struct bpf_netkit_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	__u32 flags;
+	__u32 relative_fd;
+	__u32 relative_id;
+	__u64 expected_revision;
+	size_t :0;
+};
+#define bpf_netkit_opts__last_field expected_revision
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex,
+			   const struct bpf_netkit_opts *opts);
+
+struct bpf_cgroup_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	__u32 flags;
+	__u32 relative_fd;
+	__u32 relative_id;
+	__u64 expected_revision;
+	size_t :0;
+};
+#define bpf_cgroup_opts__last_field expected_revision
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd,
+				const struct bpf_cgroup_opts *opts);
+
+struct bpf_map;
+
+LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);
+LIBBPF_API int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map);
+
+struct bpf_iter_attach_opts {
+	size_t sz; /* size of this struct for forward/backward compatibility */
+	union bpf_iter_link_info *link_info;
+	__u32 link_info_len;
+};
+#define bpf_iter_attach_opts__last_field link_info_len
+
+LIBBPF_API struct bpf_link *
+bpf_program__attach_iter(const struct bpf_program *prog,
+			 const struct bpf_iter_attach_opts *opts);
+
+LIBBPF_API enum bpf_prog_type bpf_program__type(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_type()** sets the program
+ * type of the passed BPF program.
+ * @param prog BPF program to set the program type for
+ * @param type program type to set the BPF map to have
+ * @return error code; or 0 if no error. An error occurs
+ * if the object is already loaded.
+ *
+ * This must be called before the BPF object is loaded,
+ * otherwise it has no effect and an error is returned.
+ */
+LIBBPF_API int bpf_program__set_type(struct bpf_program *prog,
+				     enum bpf_prog_type type);
+
+LIBBPF_API enum bpf_attach_type
+bpf_program__expected_attach_type(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_expected_attach_type()** sets the
+ * attach type of the passed BPF program. This is used for
+ * auto-detection of attachment when programs are loaded.
+ * @param prog BPF program to set the attach type for
+ * @param type attach type to set the BPF map to have
+ * @return error code; or 0 if no error. An error occurs
+ * if the object is already loaded.
+ *
+ * This must be called before the BPF object is loaded,
+ * otherwise it has no effect and an error is returned.
+ */
+LIBBPF_API int
+bpf_program__set_expected_attach_type(struct bpf_program *prog,
+				      enum bpf_attach_type type);
+
+LIBBPF_API __u32 bpf_program__flags(const struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_flags(struct bpf_program *prog, __u32 flags);
+
+/* Per-program log level and log buffer getters/setters.
+ * See bpf_object_open_opts comments regarding log_level and log_buf
+ * interactions.
+ */
+LIBBPF_API __u32 bpf_program__log_level(const struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level);
+LIBBPF_API const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size);
+LIBBPF_API int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size);
+
+LIBBPF_API struct bpf_func_info *bpf_program__func_info(const struct bpf_program *prog);
+LIBBPF_API __u32 bpf_program__func_info_cnt(const struct bpf_program *prog);
+
+LIBBPF_API struct bpf_line_info *bpf_program__line_info(const struct bpf_program *prog);
+LIBBPF_API __u32 bpf_program__line_info_cnt(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_attach_target()** sets BTF-based attach target
+ * for supported BPF program types:
+ *   - BTF-aware raw tracepoints (tp_btf);
+ *   - fentry/fexit/fmod_ret;
+ *   - lsm;
+ *   - freplace.
+ * @param prog BPF program to configure; must be not yet loaded.
+ * @param attach_prog_fd FD of target BPF program (for freplace/extension).
+ * If >0 and func name omitted, defers BTF ID resolution.
+ * @param attach_func_name Target function name. Used either with
+ * attach_prog_fd to find destination BTF type ID in that BPF program, or
+ * alone (no attach_prog_fd) to resolve kernel (vmlinux/module) BTF ID.
+ * Must be provided if attach_prog_fd is 0.
+ * @return error code; or 0 if no error occurred.
+ */
+LIBBPF_API int
+bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd,
+			       const char *attach_func_name);
+
+struct bpf_prog_assoc_struct_ops_opts; /* defined in bpf.h */
+
+/**
+ * @brief **bpf_program__assoc_struct_ops()** associates a BPF program with a
+ * struct_ops map.
+ *
+ * @param prog BPF program
+ * @param map struct_ops map to be associated with the BPF program
+ * @param opts optional options, can be NULL
+ *
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int
+bpf_program__assoc_struct_ops(struct bpf_program *prog, struct bpf_map *map,
+			      struct bpf_prog_assoc_struct_ops_opts *opts);
+
+/**
+ * @brief **bpf_object__find_map_by_name()** returns BPF map of
+ * the given name, if it exists within the passed BPF object
+ * @param obj BPF object
+ * @param name name of the BPF map
+ * @return BPF map instance, if such map exists within the BPF object;
+ * or NULL otherwise.
+ */
+LIBBPF_API struct bpf_map *
+bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name);
+
+LIBBPF_API int
+bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name);
+
+LIBBPF_API struct bpf_map *
+bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *map);
+
+#define bpf_object__for_each_map(pos, obj)		\
+	for ((pos) = bpf_object__next_map((obj), NULL);	\
+	     (pos) != NULL;				\
+	     (pos) = bpf_object__next_map((obj), (pos)))
+#define bpf_map__for_each bpf_object__for_each_map
+
+LIBBPF_API struct bpf_map *
+bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__set_autocreate()** sets whether libbpf has to auto-create
+ * BPF map during BPF object load phase.
+ * @param map the BPF map instance
+ * @param autocreate whether to create BPF map during BPF object load
+ * @return 0 on success; -EBUSY if BPF object was already loaded
+ *
+ * **bpf_map__set_autocreate()** allows to opt-out from libbpf auto-creating
+ * BPF map. By default, libbpf will attempt to create every single BPF map
+ * defined in BPF object file using BPF_MAP_CREATE command of bpf() syscall
+ * and fill in map FD in BPF instructions.
+ *
+ * This API allows to opt-out of this process for specific map instance. This
+ * can be useful if host kernel doesn't support such BPF map type or used
+ * combination of flags and user application wants to avoid creating such
+ * a map in the first place. User is still responsible to make sure that their
+ * BPF-side code that expects to use such missing BPF map is recognized by BPF
+ * verifier as dead code, otherwise BPF verifier will reject such BPF program.
+ */
+LIBBPF_API int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate);
+LIBBPF_API bool bpf_map__autocreate(const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__set_autoattach()** sets whether libbpf has to auto-attach
+ * map during BPF skeleton attach phase.
+ * @param map the BPF map instance
+ * @param autoattach whether to attach map during BPF skeleton attach phase
+ * @return 0 on success; negative error code, otherwise
+ */
+LIBBPF_API int bpf_map__set_autoattach(struct bpf_map *map, bool autoattach);
+
+/**
+ * @brief **bpf_map__autoattach()** returns whether BPF map is configured to
+ * auto-attach during BPF skeleton attach phase.
+ * @param map the BPF map instance
+ * @return true if map is set to auto-attach during skeleton attach phase; false, otherwise
+ */
+LIBBPF_API bool bpf_map__autoattach(const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__fd()** gets the file descriptor of the passed
+ * BPF map
+ * @param map the BPF map instance
+ * @return the file descriptor; or -EINVAL in case of an error
+ */
+LIBBPF_API int bpf_map__fd(const struct bpf_map *map);
+LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
+/* get map name */
+LIBBPF_API const char *bpf_map__name(const struct bpf_map *map);
+/* get/set map type */
+LIBBPF_API enum bpf_map_type bpf_map__type(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type);
+/* get/set map size (max_entries) */
+LIBBPF_API __u32 bpf_map__max_entries(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries);
+/* get/set map flags */
+LIBBPF_API __u32 bpf_map__map_flags(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags);
+/* get/set map NUMA node */
+LIBBPF_API __u32 bpf_map__numa_node(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node);
+/* get/set map key size */
+LIBBPF_API __u32 bpf_map__key_size(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_key_size(struct bpf_map *map, __u32 size);
+/* get map value size */
+LIBBPF_API __u32 bpf_map__value_size(const struct bpf_map *map);
+/**
+ * @brief **bpf_map__set_value_size()** sets map value size.
+ * @param map the BPF map instance
+ * @param size the new value size
+ * @return 0, on success; negative error, otherwise
+ *
+ * There is a special case for maps with associated memory-mapped regions, like
+ * the global data section maps (bss, data, rodata). When this function is used
+ * on such a map, the mapped region is resized. Afterward, an attempt is made to
+ * adjust the corresponding BTF info. This attempt is best-effort and can only
+ * succeed if the last variable of the data section map is an array. The array
+ * BTF type is replaced by a new BTF array type with a different length.
+ * Any previously existing pointers returned from bpf_map__initial_value() or
+ * corresponding data section skeleton pointer must be reinitialized.
+ */
+LIBBPF_API int bpf_map__set_value_size(struct bpf_map *map, __u32 size);
+/* get map key/value BTF type IDs */
+LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
+LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
+/* get/set map if_index */
+LIBBPF_API __u32 bpf_map__ifindex(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
+/* get/set map map_extra flags */
+LIBBPF_API __u64 bpf_map__map_extra(const struct bpf_map *map);
+LIBBPF_API int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra);
+
+LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
+					  const void *data, size_t size);
+LIBBPF_API void *bpf_map__initial_value(const struct bpf_map *map, size_t *psize);
+
+/**
+ * @brief **bpf_map__is_internal()** tells the caller whether or not the
+ * passed map is a special map created by libbpf automatically for things like
+ * global variables, __ksym externs, Kconfig values, etc
+ * @param map the bpf_map
+ * @return true, if the map is an internal map; false, otherwise
+ */
+LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__set_pin_path()** sets the path attribute that tells where the
+ * BPF map should be pinned. This does not actually create the 'pin'.
+ * @param map The bpf_map
+ * @param path The path
+ * @return 0, on success; negative error, otherwise
+ */
+LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path);
+
+/**
+ * @brief **bpf_map__pin_path()** gets the path attribute that tells where the
+ * BPF map should be pinned.
+ * @param map The bpf_map
+ * @return The path string; which can be NULL
+ */
+LIBBPF_API const char *bpf_map__pin_path(const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__is_pinned()** tells the caller whether or not the
+ * passed map has been pinned via a 'pin' file.
+ * @param map The bpf_map
+ * @return true, if the map is pinned; false, otherwise
+ */
+LIBBPF_API bool bpf_map__is_pinned(const struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__pin()** creates a file that serves as a 'pin'
+ * for the BPF map. This increments the reference count on the
+ * BPF map which will keep the BPF map loaded even after the
+ * userspace process which loaded it has exited.
+ * @param map The bpf_map to pin
+ * @param path A file path for the 'pin'
+ * @return 0, on success; negative error, otherwise
+ *
+ * If `path` is NULL the maps `pin_path` attribute will be used. If this is
+ * also NULL, an error will be returned and the map will not be pinned.
+ */
+LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
+
+/**
+ * @brief **bpf_map__unpin()** removes the file that serves as a
+ * 'pin' for the BPF map.
+ * @param map The bpf_map to unpin
+ * @param path A file path for the 'pin'
+ * @return 0, on success; negative error, otherwise
+ *
+ * The `path` parameter can be NULL, in which case the `pin_path`
+ * map attribute is unpinned. If both the `path` parameter and
+ * `pin_path` map attribute are set, they must be equal.
+ */
+LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
+
+LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd);
+LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map);
+
+/**
+ * @brief **bpf_map__lookup_elem()** allows to lookup BPF map value
+ * corresponding to provided key.
+ * @param map BPF map to lookup element in
+ * @param key pointer to memory containing bytes of the key used for lookup
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @param value pointer to memory in which looked up value will be stored
+ * @param value_sz size in byte of value data memory; it has to match BPF map
+ * definition's **value_size**. For per-CPU BPF maps, value size can be
+ * `value_size` if either **BPF_F_CPU** or **BPF_F_ALL_CPUS** is specified
+ * in **flags**, otherwise a product of BPF map value size and number of
+ * possible CPUs in the system (could be fetched with
+ * **libbpf_num_possible_cpus()**). Note also that for per-CPU values value
+ * size has to be aligned up to closest 8 bytes, so expected size is:
+ * `round_up(value_size, 8) * libbpf_num_possible_cpus()`.
+ * @param flags extra flags passed to kernel for this operation
+ * @return 0, on success; negative error, otherwise
+ *
+ * **bpf_map__lookup_elem()** is high-level equivalent of
+ * **bpf_map_lookup_elem()** API with added check for key and value size.
+ */
+LIBBPF_API int bpf_map__lookup_elem(const struct bpf_map *map,
+				    const void *key, size_t key_sz,
+				    void *value, size_t value_sz, __u64 flags);
+
+/**
+ * @brief **bpf_map__update_elem()** allows to insert or update value in BPF
+ * map that corresponds to provided key.
+ * @param map BPF map to insert to or update element in
+ * @param key pointer to memory containing bytes of the key
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @param value pointer to memory containing bytes of the value
+ * @param value_sz refer to **bpf_map__lookup_elem**'s description.'
+ * @param flags extra flags passed to kernel for this operation
+ * @return 0, on success; negative error, otherwise
+ *
+ * **bpf_map__update_elem()** is high-level equivalent of
+ * **bpf_map_update_elem()** API with added check for key and value size.
+ */
+LIBBPF_API int bpf_map__update_elem(const struct bpf_map *map,
+				    const void *key, size_t key_sz,
+				    const void *value, size_t value_sz, __u64 flags);
+
+/**
+ * @brief **bpf_map__delete_elem()** allows to delete element in BPF map that
+ * corresponds to provided key.
+ * @param map BPF map to delete element from
+ * @param key pointer to memory containing bytes of the key
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @param flags extra flags passed to kernel for this operation
+ * @return 0, on success; negative error, otherwise
+ *
+ * **bpf_map__delete_elem()** is high-level equivalent of
+ * **bpf_map_delete_elem()** API with added check for key size.
+ */
+LIBBPF_API int bpf_map__delete_elem(const struct bpf_map *map,
+				    const void *key, size_t key_sz, __u64 flags);
+
+/**
+ * @brief **bpf_map__lookup_and_delete_elem()** allows to lookup BPF map value
+ * corresponding to provided key and atomically delete it afterwards.
+ * @param map BPF map to lookup element in
+ * @param key pointer to memory containing bytes of the key used for lookup
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @param value pointer to memory in which looked up value will be stored
+ * @param value_sz size in byte of value data memory; it has to match BPF map
+ * definition's **value_size**. For per-CPU BPF maps value size has to be
+ * a product of BPF map value size and number of possible CPUs in the system
+ * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for
+ * per-CPU values value size has to be aligned up to closest 8 bytes for
+ * alignment reasons, so expected size is: `round_up(value_size, 8)
+ * * libbpf_num_possible_cpus()`.
+ * @param flags extra flags passed to kernel for this operation
+ * @return 0, on success; negative error, otherwise
+ *
+ * **bpf_map__lookup_and_delete_elem()** is high-level equivalent of
+ * **bpf_map_lookup_and_delete_elem()** API with added check for key and value size.
+ */
+LIBBPF_API int bpf_map__lookup_and_delete_elem(const struct bpf_map *map,
+					       const void *key, size_t key_sz,
+					       void *value, size_t value_sz, __u64 flags);
+
+/**
+ * @brief **bpf_map__get_next_key()** allows to iterate BPF map keys by
+ * fetching next key that follows current key.
+ * @param map BPF map to fetch next key from
+ * @param cur_key pointer to memory containing bytes of current key or NULL to
+ * fetch the first key
+ * @param next_key pointer to memory to write next key into
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @return 0, on success; -ENOENT if **cur_key** is the last key in BPF map;
+ * negative error, otherwise
+ *
+ * **bpf_map__get_next_key()** is high-level equivalent of
+ * **bpf_map_get_next_key()** API with added check for key size.
+ */
+LIBBPF_API int bpf_map__get_next_key(const struct bpf_map *map,
+				     const void *cur_key, void *next_key, size_t key_sz);
+/**
+ * @brief **bpf_map__set_exclusive_program()** sets a map to be exclusive to the
+ * specified program. This must be called *before* the map is created.
+ *
+ * @param map BPF map to make exclusive.
+ * @param prog BPF program to be the exclusive user of the map. Must belong
+ * to the same bpf_object as the map.
+ * @return 0 on success; a negative error code otherwise.
+ *
+ * This function must be called after the BPF object is opened but before
+ * it is loaded. Once the object is loaded, only the specified program
+ * will be able to access the map's contents.
+ */
+LIBBPF_API int bpf_map__set_exclusive_program(struct bpf_map *map, struct bpf_program *prog);
+
+/**
+ * @brief **bpf_map__exclusive_program()** returns the exclusive program
+ * that is registered with the map (if any).
+ * @param map BPF map to which the exclusive program is registered.
+ * @return the registered exclusive program.
+ */
+LIBBPF_API struct bpf_program *bpf_map__exclusive_program(struct bpf_map *map);
+
+struct bpf_xdp_set_link_opts {
+	size_t sz;
+	int old_fd;
+	size_t :0;
+};
+#define bpf_xdp_set_link_opts__last_field old_fd
+
+struct bpf_xdp_attach_opts {
+	size_t sz;
+	int old_prog_fd;
+	size_t :0;
+};
+#define bpf_xdp_attach_opts__last_field old_prog_fd
+
+struct bpf_xdp_query_opts {
+	size_t sz;
+	__u32 prog_id;		/* output */
+	__u32 drv_prog_id;	/* output */
+	__u32 hw_prog_id;	/* output */
+	__u32 skb_prog_id;	/* output */
+	__u8 attach_mode;	/* output */
+	__u64 feature_flags;	/* output */
+	__u32 xdp_zc_max_segs;	/* output */
+	size_t :0;
+};
+#define bpf_xdp_query_opts__last_field xdp_zc_max_segs
+
+LIBBPF_API int bpf_xdp_attach(int ifindex, int prog_fd, __u32 flags,
+			      const struct bpf_xdp_attach_opts *opts);
+LIBBPF_API int bpf_xdp_detach(int ifindex, __u32 flags,
+			      const struct bpf_xdp_attach_opts *opts);
+LIBBPF_API int bpf_xdp_query(int ifindex, int flags, struct bpf_xdp_query_opts *opts);
+LIBBPF_API int bpf_xdp_query_id(int ifindex, int flags, __u32 *prog_id);
+
+/* TC related API */
+enum bpf_tc_attach_point {
+	BPF_TC_INGRESS = 1 << 0,
+	BPF_TC_EGRESS  = 1 << 1,
+	BPF_TC_CUSTOM  = 1 << 2,
+	BPF_TC_QDISC   = 1 << 3,
+};
+
+#define BPF_TC_PARENT(a, b) 	\
+	((((a) << 16) & 0xFFFF0000U) | ((b) & 0x0000FFFFU))
+
+enum bpf_tc_flags {
+	BPF_TC_F_REPLACE = 1 << 0,
+};
+
+struct bpf_tc_hook {
+	size_t sz;
+	int ifindex;
+	enum bpf_tc_attach_point attach_point;
+	__u32 parent;
+	__u32 handle;
+	const char *qdisc;
+	size_t :0;
+};
+#define bpf_tc_hook__last_field qdisc
+
+struct bpf_tc_opts {
+	size_t sz;
+	int prog_fd;
+	__u32 flags;
+	__u32 prog_id;
+	__u32 handle;
+	__u32 priority;
+	size_t :0;
+};
+#define bpf_tc_opts__last_field priority
+
+LIBBPF_API int bpf_tc_hook_create(struct bpf_tc_hook *hook);
+LIBBPF_API int bpf_tc_hook_destroy(struct bpf_tc_hook *hook);
+LIBBPF_API int bpf_tc_attach(const struct bpf_tc_hook *hook,
+			     struct bpf_tc_opts *opts);
+LIBBPF_API int bpf_tc_detach(const struct bpf_tc_hook *hook,
+			     const struct bpf_tc_opts *opts);
+LIBBPF_API int bpf_tc_query(const struct bpf_tc_hook *hook,
+			    struct bpf_tc_opts *opts);
+
+/* Ring buffer APIs */
+struct ring_buffer;
+struct ring;
+struct user_ring_buffer;
+
+typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size);
+
+struct ring_buffer_opts {
+	size_t sz; /* size of this struct, for forward/backward compatibility */
+};
+
+#define ring_buffer_opts__last_field sz
+
+LIBBPF_API struct ring_buffer *
+ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx,
+		 const struct ring_buffer_opts *opts);
+LIBBPF_API void ring_buffer__free(struct ring_buffer *rb);
+LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
+				ring_buffer_sample_fn sample_cb, void *ctx);
+LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
+LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
+LIBBPF_API int ring_buffer__consume_n(struct ring_buffer *rb, size_t n);
+LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
+
+/**
+ * @brief **ring_buffer__ring()** returns the ringbuffer object inside a given
+ * ringbuffer manager representing a single BPF_MAP_TYPE_RINGBUF map instance.
+ *
+ * @param rb A ringbuffer manager object.
+ * @param idx An index into the ringbuffers contained within the ringbuffer
+ * manager object. The index is 0-based and corresponds to the order in which
+ * ring_buffer__add was called.
+ * @return A ringbuffer object on success; NULL and errno set if the index is
+ * invalid.
+ */
+LIBBPF_API struct ring *ring_buffer__ring(struct ring_buffer *rb,
+					  unsigned int idx);
+
+/**
+ * @brief **ring__consumer_pos()** returns the current consumer position in the
+ * given ringbuffer.
+ *
+ * @param r A ringbuffer object.
+ * @return The current consumer position.
+ */
+LIBBPF_API unsigned long ring__consumer_pos(const struct ring *r);
+
+/**
+ * @brief **ring__producer_pos()** returns the current producer position in the
+ * given ringbuffer.
+ *
+ * @param r A ringbuffer object.
+ * @return The current producer position.
+ */
+LIBBPF_API unsigned long ring__producer_pos(const struct ring *r);
+
+/**
+ * @brief **ring__avail_data_size()** returns the number of bytes in the
+ * ringbuffer not yet consumed. This has no locking associated with it, so it
+ * can be inaccurate if operations are ongoing while this is called. However, it
+ * should still show the correct trend over the long-term.
+ *
+ * @param r A ringbuffer object.
+ * @return The number of bytes not yet consumed.
+ */
+LIBBPF_API size_t ring__avail_data_size(const struct ring *r);
+
+/**
+ * @brief **ring__size()** returns the total size of the ringbuffer's map data
+ * area (excluding special producer/consumer pages). Effectively this gives the
+ * amount of usable bytes of data inside the ringbuffer.
+ *
+ * @param r A ringbuffer object.
+ * @return The total size of the ringbuffer map data area.
+ */
+LIBBPF_API size_t ring__size(const struct ring *r);
+
+/**
+ * @brief **ring__map_fd()** returns the file descriptor underlying the given
+ * ringbuffer.
+ *
+ * @param r A ringbuffer object.
+ * @return The underlying ringbuffer file descriptor
+ */
+LIBBPF_API int ring__map_fd(const struct ring *r);
+
+/**
+ * @brief **ring__consume()** consumes available ringbuffer data without event
+ * polling.
+ *
+ * @param r A ringbuffer object.
+ * @return The number of records consumed (or INT_MAX, whichever is less), or
+ * a negative number if any of the callbacks return an error.
+ */
+LIBBPF_API int ring__consume(struct ring *r);
+
+/**
+ * @brief **ring__consume_n()** consumes up to a requested amount of items from
+ * a ringbuffer without event polling.
+ *
+ * @param r A ringbuffer object.
+ * @param n Maximum amount of items to consume.
+ * @return The number of items consumed, or a negative number if any of the
+ * callbacks return an error.
+ */
+LIBBPF_API int ring__consume_n(struct ring *r, size_t n);
+
+struct user_ring_buffer_opts {
+	size_t sz; /* size of this struct, for forward/backward compatibility */
+};
+
+#define user_ring_buffer_opts__last_field sz
+
+/**
+ * @brief **user_ring_buffer__new()** creates a new instance of a user ring
+ * buffer.
+ *
+ * @param map_fd A file descriptor to a BPF_MAP_TYPE_USER_RINGBUF map.
+ * @param opts Options for how the ring buffer should be created.
+ * @return A user ring buffer on success; NULL and errno being set on a
+ * failure.
+ */
+LIBBPF_API struct user_ring_buffer *
+user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts);
+
+/**
+ * @brief **user_ring_buffer__reserve()** reserves a pointer to a sample in the
+ * user ring buffer.
+ * @param rb A pointer to a user ring buffer.
+ * @param size The size of the sample, in bytes.
+ * @return A pointer to an 8-byte aligned reserved region of the user ring
+ * buffer; NULL, and errno being set if a sample could not be reserved.
+ *
+ * This function is *not* thread safe, and callers must synchronize accessing
+ * this function if there are multiple producers.  If a size is requested that
+ * is larger than the size of the entire ring buffer, errno will be set to
+ * E2BIG and NULL is returned. If the ring buffer could accommodate the size,
+ * but currently does not have enough space, errno is set to ENOSPC and NULL is
+ * returned.
+ *
+ * After initializing the sample, callers must invoke
+ * **user_ring_buffer__submit()** to post the sample to the kernel. Otherwise,
+ * the sample must be freed with **user_ring_buffer__discard()**.
+ */
+LIBBPF_API void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
+
+/**
+ * @brief **user_ring_buffer__reserve_blocking()** reserves a record in the
+ * ring buffer, possibly blocking for up to @timeout_ms until a sample becomes
+ * available.
+ * @param rb The user ring buffer.
+ * @param size The size of the sample, in bytes.
+ * @param timeout_ms The amount of time, in milliseconds, for which the caller
+ * should block when waiting for a sample. -1 causes the caller to block
+ * indefinitely.
+ * @return A pointer to an 8-byte aligned reserved region of the user ring
+ * buffer; NULL, and errno being set if a sample could not be reserved.
+ *
+ * This function is *not* thread safe, and callers must synchronize
+ * accessing this function if there are multiple producers
+ *
+ * If **timeout_ms** is -1, the function will block indefinitely until a sample
+ * becomes available. Otherwise, **timeout_ms** must be non-negative, or errno
+ * is set to EINVAL, and NULL is returned. If **timeout_ms** is 0, no blocking
+ * will occur and the function will return immediately after attempting to
+ * reserve a sample.
+ *
+ * If **size** is larger than the size of the entire ring buffer, errno is set
+ * to E2BIG and NULL is returned. If the ring buffer could accommodate
+ * **size**, but currently does not have enough space, the caller will block
+ * until at most **timeout_ms** has elapsed. If insufficient space is available
+ * at that time, errno is set to ENOSPC, and NULL is returned.
+ *
+ * The kernel guarantees that it will wake up this thread to check if
+ * sufficient space is available in the ring buffer at least once per
+ * invocation of the **bpf_ringbuf_drain()** helper function, provided that at
+ * least one sample is consumed, and the BPF program did not invoke the
+ * function with BPF_RB_NO_WAKEUP. A wakeup may occur sooner than that, but the
+ * kernel does not guarantee this. If the helper function is invoked with
+ * BPF_RB_FORCE_WAKEUP, a wakeup event will be sent even if no sample is
+ * consumed.
+ *
+ * When a sample of size **size** is found within **timeout_ms**, a pointer to
+ * the sample is returned. After initializing the sample, callers must invoke
+ * **user_ring_buffer__submit()** to post the sample to the ring buffer.
+ * Otherwise, the sample must be freed with **user_ring_buffer__discard()**.
+ */
+LIBBPF_API void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
+						    __u32 size,
+						    int timeout_ms);
+
+/**
+ * @brief **user_ring_buffer__submit()** submits a previously reserved sample
+ * into the ring buffer.
+ * @param rb The user ring buffer.
+ * @param sample A reserved sample.
+ *
+ * It is not necessary to synchronize amongst multiple producers when invoking
+ * this function.
+ */
+LIBBPF_API void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
+
+/**
+ * @brief **user_ring_buffer__discard()** discards a previously reserved sample.
+ * @param rb The user ring buffer.
+ * @param sample A reserved sample.
+ *
+ * It is not necessary to synchronize amongst multiple producers when invoking
+ * this function.
+ */
+LIBBPF_API void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample);
+
+/**
+ * @brief **user_ring_buffer__free()** frees a ring buffer that was previously
+ * created with **user_ring_buffer__new()**.
+ * @param rb The user ring buffer being freed.
+ */
+LIBBPF_API void user_ring_buffer__free(struct user_ring_buffer *rb);
+
+/* Perf buffer APIs */
+struct perf_buffer;
+
+typedef void (*perf_buffer_sample_fn)(void *ctx, int cpu,
+				      void *data, __u32 size);
+typedef void (*perf_buffer_lost_fn)(void *ctx, int cpu, __u64 cnt);
+
+/* common use perf buffer options */
+struct perf_buffer_opts {
+	size_t sz;
+	__u32 sample_period;
+	size_t :0;
+};
+#define perf_buffer_opts__last_field sample_period
+
+/**
+ * @brief **perf_buffer__new()** creates BPF perfbuf manager for a specified
+ * BPF_PERF_EVENT_ARRAY map
+ * @param map_fd FD of BPF_PERF_EVENT_ARRAY BPF map that will be used by BPF
+ * code to send data over to user-space
+ * @param page_cnt number of memory pages allocated for each per-CPU buffer
+ * @param sample_cb function called on each received data record
+ * @param lost_cb function called when record loss has occurred
+ * @param ctx user-provided extra context passed into *sample_cb* and *lost_cb*
+ * @param opts optional parameters for the perf buffer, can be null
+ * @return a new instance of struct perf_buffer on success, NULL on error with
+ * *errno* containing an error code
+ */
+LIBBPF_API struct perf_buffer *
+perf_buffer__new(int map_fd, size_t page_cnt,
+		 perf_buffer_sample_fn sample_cb, perf_buffer_lost_fn lost_cb, void *ctx,
+		 const struct perf_buffer_opts *opts);
+
+enum bpf_perf_event_ret {
+	LIBBPF_PERF_EVENT_DONE	= 0,
+	LIBBPF_PERF_EVENT_ERROR	= -1,
+	LIBBPF_PERF_EVENT_CONT	= -2,
+};
+
+struct perf_event_header;
+
+typedef enum bpf_perf_event_ret
+(*perf_buffer_event_fn)(void *ctx, int cpu, struct perf_event_header *event);
+
+/* raw perf buffer options, giving most power and control */
+struct perf_buffer_raw_opts {
+	size_t sz;
+	long :0;
+	long :0;
+	/* if cpu_cnt == 0, open all on all possible CPUs (up to the number of
+	 * max_entries of given PERF_EVENT_ARRAY map)
+	 */
+	int cpu_cnt;
+	/* if cpu_cnt > 0, cpus is an array of CPUs to open ring buffers on */
+	int *cpus;
+	/* if cpu_cnt > 0, map_keys specify map keys to set per-CPU FDs for */
+	int *map_keys;
+};
+#define perf_buffer_raw_opts__last_field map_keys
+
+struct perf_event_attr;
+
+LIBBPF_API struct perf_buffer *
+perf_buffer__new_raw(int map_fd, size_t page_cnt, struct perf_event_attr *attr,
+		     perf_buffer_event_fn event_cb, void *ctx,
+		     const struct perf_buffer_raw_opts *opts);
+
+LIBBPF_API void perf_buffer__free(struct perf_buffer *pb);
+LIBBPF_API int perf_buffer__epoll_fd(const struct perf_buffer *pb);
+LIBBPF_API int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms);
+LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb);
+LIBBPF_API int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx);
+LIBBPF_API size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb);
+LIBBPF_API int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx);
+/**
+ * @brief **perf_buffer__buffer()** returns the per-cpu raw mmap()'ed underlying
+ * memory region of the ring buffer.
+ * This ring buffer can be used to implement a custom events consumer.
+ * The ring buffer starts with the *struct perf_event_mmap_page*, which
+ * holds the ring buffer management fields, when accessing the header
+ * structure it's important to be SMP aware.
+ * You can refer to *perf_event_read_simple* for a simple example.
+ * @param pb the perf buffer structure
+ * @param buf_idx the buffer index to retrieve
+ * @param buf (out) gets the base pointer of the mmap()'ed memory
+ * @param buf_size (out) gets the size of the mmap()'ed region
+ * @return 0 on success, negative error code for failure
+ */
+LIBBPF_API int perf_buffer__buffer(struct perf_buffer *pb, int buf_idx, void **buf,
+				   size_t *buf_size);
+
+struct bpf_prog_linfo;
+struct bpf_prog_info;
+
+LIBBPF_API void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo);
+LIBBPF_API struct bpf_prog_linfo *
+bpf_prog_linfo__new(const struct bpf_prog_info *info);
+LIBBPF_API const struct bpf_line_info *
+bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo,
+				__u64 addr, __u32 func_idx, __u32 nr_skip);
+LIBBPF_API const struct bpf_line_info *
+bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo,
+		      __u32 insn_off, __u32 nr_skip);
+
+/*
+ * Probe for supported system features
+ *
+ * Note that running many of these probes in a short amount of time can cause
+ * the kernel to reach the maximal size of lockable memory allowed for the
+ * user, causing subsequent probes to fail. In this case, the caller may want
+ * to adjust that limit with setrlimit().
+ */
+
+/**
+ * @brief **libbpf_probe_bpf_prog_type()** detects if host kernel supports
+ * BPF programs of a given type.
+ * @param prog_type BPF program type to detect kernel support for
+ * @param opts reserved for future extensibility, should be NULL
+ * @return 1, if given program type is supported; 0, if given program type is
+ * not supported; negative error code if feature detection failed or can't be
+ * performed
+ *
+ * Make sure the process has required set of CAP_* permissions (or runs as
+ * root) when performing feature checking.
+ */
+LIBBPF_API int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts);
+/**
+ * @brief **libbpf_probe_bpf_map_type()** detects if host kernel supports
+ * BPF maps of a given type.
+ * @param map_type BPF map type to detect kernel support for
+ * @param opts reserved for future extensibility, should be NULL
+ * @return 1, if given map type is supported; 0, if given map type is
+ * not supported; negative error code if feature detection failed or can't be
+ * performed
+ *
+ * Make sure the process has required set of CAP_* permissions (or runs as
+ * root) when performing feature checking.
+ */
+LIBBPF_API int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts);
+/**
+ * @brief **libbpf_probe_bpf_helper()** detects if host kernel supports the
+ * use of a given BPF helper from specified BPF program type.
+ * @param prog_type BPF program type used to check the support of BPF helper
+ * @param helper_id BPF helper ID (enum bpf_func_id) to check support for
+ * @param opts reserved for future extensibility, should be NULL
+ * @return 1, if given combination of program type and helper is supported; 0,
+ * if the combination is not supported; negative error code if feature
+ * detection for provided input arguments failed or can't be performed
+ *
+ * Make sure the process has required set of CAP_* permissions (or runs as
+ * root) when performing feature checking.
+ */
+LIBBPF_API int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type,
+				       enum bpf_func_id helper_id, const void *opts);
+
+/**
+ * @brief **libbpf_num_possible_cpus()** is a helper function to get the
+ * number of possible CPUs that the host kernel supports and expects.
+ * @return number of possible CPUs; or error code on failure
+ *
+ * Example usage:
+ *
+ *     int ncpus = libbpf_num_possible_cpus();
+ *     if (ncpus < 0) {
+ *          // error handling
+ *     }
+ *     long values[ncpus];
+ *     bpf_map_lookup_elem(per_cpu_map_fd, key, values);
+ */
+LIBBPF_API int libbpf_num_possible_cpus(void);
+
+struct bpf_map_skeleton {
+	const char *name;
+	struct bpf_map **map;
+	void **mmaped;
+	struct bpf_link **link;
+};
+
+struct bpf_prog_skeleton {
+	const char *name;
+	struct bpf_program **prog;
+	struct bpf_link **link;
+};
+
+struct bpf_object_skeleton {
+	size_t sz; /* size of this struct, for forward/backward compatibility */
+
+	const char *name;
+	const void *data;
+	size_t data_sz;
+
+	struct bpf_object **obj;
+
+	int map_cnt;
+	int map_skel_sz; /* sizeof(struct bpf_map_skeleton) */
+	struct bpf_map_skeleton *maps;
+
+	int prog_cnt;
+	int prog_skel_sz; /* sizeof(struct bpf_prog_skeleton) */
+	struct bpf_prog_skeleton *progs;
+};
+
+LIBBPF_API int
+bpf_object__open_skeleton(struct bpf_object_skeleton *s,
+			  const struct bpf_object_open_opts *opts);
+LIBBPF_API int bpf_object__load_skeleton(struct bpf_object_skeleton *s);
+LIBBPF_API int bpf_object__attach_skeleton(struct bpf_object_skeleton *s);
+LIBBPF_API void bpf_object__detach_skeleton(struct bpf_object_skeleton *s);
+LIBBPF_API void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s);
+
+struct bpf_var_skeleton {
+	const char *name;
+	struct bpf_map **map;
+	void **addr;
+};
+
+struct bpf_object_subskeleton {
+	size_t sz; /* size of this struct, for forward/backward compatibility */
+
+	const struct bpf_object *obj;
+
+	int map_cnt;
+	int map_skel_sz; /* sizeof(struct bpf_map_skeleton) */
+	struct bpf_map_skeleton *maps;
+
+	int prog_cnt;
+	int prog_skel_sz; /* sizeof(struct bpf_prog_skeleton) */
+	struct bpf_prog_skeleton *progs;
+
+	int var_cnt;
+	int var_skel_sz; /* sizeof(struct bpf_var_skeleton) */
+	struct bpf_var_skeleton *vars;
+};
+
+LIBBPF_API int
+bpf_object__open_subskeleton(struct bpf_object_subskeleton *s);
+LIBBPF_API void
+bpf_object__destroy_subskeleton(struct bpf_object_subskeleton *s);
+
+struct gen_loader_opts {
+	size_t sz; /* size of this struct, for forward/backward compatibility */
+	const char *data;
+	const char *insns;
+	__u32 data_sz;
+	__u32 insns_sz;
+	bool gen_hash;
+};
+
+#define gen_loader_opts__last_field gen_hash
+LIBBPF_API int bpf_object__gen_loader(struct bpf_object *obj,
+				      struct gen_loader_opts *opts);
+
+enum libbpf_tristate {
+	TRI_NO = 0,
+	TRI_YES = 1,
+	TRI_MODULE = 2,
+};
+
+struct bpf_linker_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+};
+#define bpf_linker_opts__last_field sz
+
+struct bpf_linker_file_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+};
+#define bpf_linker_file_opts__last_field sz
+
+struct bpf_linker;
+
+LIBBPF_API struct bpf_linker *bpf_linker__new(const char *filename, struct bpf_linker_opts *opts);
+LIBBPF_API struct bpf_linker *bpf_linker__new_fd(int fd, struct bpf_linker_opts *opts);
+LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker,
+				    const char *filename,
+				    const struct bpf_linker_file_opts *opts);
+LIBBPF_API int bpf_linker__add_fd(struct bpf_linker *linker, int fd,
+				  const struct bpf_linker_file_opts *opts);
+LIBBPF_API int bpf_linker__add_buf(struct bpf_linker *linker, void *buf, size_t buf_sz,
+				   const struct bpf_linker_file_opts *opts);
+LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker);
+LIBBPF_API void bpf_linker__free(struct bpf_linker *linker);
+
+/*
+ * Custom handling of BPF program's SEC() definitions
+ */
+
+struct bpf_prog_load_opts; /* defined in bpf.h */
+
+/* Called during bpf_object__open() for each recognized BPF program. Callback
+ * can use various bpf_program__set_*() setters to adjust whatever properties
+ * are necessary.
+ */
+typedef int (*libbpf_prog_setup_fn_t)(struct bpf_program *prog, long cookie);
+
+/* Called right before libbpf performs bpf_prog_load() to load BPF program
+ * into the kernel. Callback can adjust opts as necessary.
+ */
+typedef int (*libbpf_prog_prepare_load_fn_t)(struct bpf_program *prog,
+					     struct bpf_prog_load_opts *opts, long cookie);
+
+/* Called during skeleton attach or through bpf_program__attach(). If
+ * auto-attach is not supported, callback should return 0 and set link to
+ * NULL (it's not considered an error during skeleton attach, but it will be
+ * an error for bpf_program__attach() calls). On error, error should be
+ * returned directly and link set to NULL. On success, return 0 and set link
+ * to a valid struct bpf_link.
+ */
+typedef int (*libbpf_prog_attach_fn_t)(const struct bpf_program *prog, long cookie,
+				       struct bpf_link **link);
+
+struct libbpf_prog_handler_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+	/* User-provided value that is passed to prog_setup_fn,
+	 * prog_prepare_load_fn, and prog_attach_fn callbacks. Allows user to
+	 * register one set of callbacks for multiple SEC() definitions and
+	 * still be able to distinguish them, if necessary. For example,
+	 * libbpf itself is using this to pass necessary flags (e.g.,
+	 * sleepable flag) to a common internal SEC() handler.
+	 */
+	long cookie;
+	/* BPF program initialization callback (see libbpf_prog_setup_fn_t).
+	 * Callback is optional, pass NULL if it's not necessary.
+	 */
+	libbpf_prog_setup_fn_t prog_setup_fn;
+	/* BPF program loading callback (see libbpf_prog_prepare_load_fn_t).
+	 * Callback is optional, pass NULL if it's not necessary.
+	 */
+	libbpf_prog_prepare_load_fn_t prog_prepare_load_fn;
+	/* BPF program attach callback (see libbpf_prog_attach_fn_t).
+	 * Callback is optional, pass NULL if it's not necessary.
+	 */
+	libbpf_prog_attach_fn_t prog_attach_fn;
+};
+#define libbpf_prog_handler_opts__last_field prog_attach_fn
+
+/**
+ * @brief **libbpf_register_prog_handler()** registers a custom BPF program
+ * SEC() handler.
+ * @param sec section prefix for which custom handler is registered
+ * @param prog_type BPF program type associated with specified section
+ * @param exp_attach_type Expected BPF attach type associated with specified section
+ * @param opts optional cookie, callbacks, and other extra options
+ * @return Non-negative handler ID is returned on success. This handler ID has
+ * to be passed to *libbpf_unregister_prog_handler()* to unregister such
+ * custom handler. Negative error code is returned on error.
+ *
+ * *sec* defines which SEC() definitions are handled by this custom handler
+ * registration. *sec* can have few different forms:
+ *   - if *sec* is just a plain string (e.g., "abc"), it will match only
+ *   SEC("abc"). If BPF program specifies SEC("abc/whatever") it will result
+ *   in an error;
+ *   - if *sec* is of the form "abc/", proper SEC() form is
+ *   SEC("abc/something"), where acceptable "something" should be checked by
+ *   *prog_init_fn* callback, if there are additional restrictions;
+ *   - if *sec* is of the form "abc+", it will successfully match both
+ *   SEC("abc") and SEC("abc/whatever") forms;
+ *   - if *sec* is NULL, custom handler is registered for any BPF program that
+ *   doesn't match any of the registered (custom or libbpf's own) SEC()
+ *   handlers. There could be only one such generic custom handler registered
+ *   at any given time.
+ *
+ * All custom handlers (except the one with *sec* == NULL) are processed
+ * before libbpf's own SEC() handlers. It is allowed to "override" libbpf's
+ * SEC() handlers by registering custom ones for the same section prefix
+ * (i.e., it's possible to have custom SEC("perf_event/LLC-load-misses")
+ * handler).
+ *
+ * Note, like much of global libbpf APIs (e.g., libbpf_set_print(),
+ * libbpf_set_strict_mode(), etc)) these APIs are not thread-safe. User needs
+ * to ensure synchronization if there is a risk of running this API from
+ * multiple threads simultaneously.
+ */
+LIBBPF_API int libbpf_register_prog_handler(const char *sec,
+					    enum bpf_prog_type prog_type,
+					    enum bpf_attach_type exp_attach_type,
+					    const struct libbpf_prog_handler_opts *opts);
+/**
+ * @brief *libbpf_unregister_prog_handler()* unregisters previously registered
+ * custom BPF program SEC() handler.
+ * @param handler_id handler ID returned by *libbpf_register_prog_handler()*
+ * after successful registration
+ * @return 0 on success, negative error code if handler isn't found
+ *
+ * Note, like much of global libbpf APIs (e.g., libbpf_set_print(),
+ * libbpf_set_strict_mode(), etc)) these APIs are not thread-safe. User needs
+ * to ensure synchronization if there is a risk of running this API from
+ * multiple threads simultaneously.
+ */
+LIBBPF_API int libbpf_unregister_prog_handler(int handler_id);
+
+/**
+ * @brief **bpf_program__clone()** loads a single BPF program from a prepared
+ * BPF object into the kernel, returning its file descriptor.
+ *
+ * The BPF object must have been previously prepared with
+ * **bpf_object__prepare()**. If @opts is provided, any non-zero field
+ * overrides the defaults derived from the program/object internals.
+ * If @opts is NULL, all fields are populated automatically.
+ *
+ * The returned FD is owned by the caller and must be closed with close().
+ *
+ * @param prog BPF program from a prepared object
+ * @param opts Optional load options; non-zero fields override defaults
+ * @return program FD (>= 0) on success; negative error code on failure
+ */
+LIBBPF_API int bpf_program__clone(struct bpf_program *prog, const struct bpf_prog_load_opts *opts);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* __LIBBPF_LIBBPF_H */
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
new file mode 100644
index 000000000..08ab2ea88
--- /dev/null
+++ b/tools/lib/bpf/libbpf.map
@@ -0,0 +1,465 @@
+LIBBPF_0.0.1 {
+	global:
+		bpf_btf_get_fd_by_id;
+		bpf_map__btf_key_type_id;
+		bpf_map__btf_value_type_id;
+		bpf_map__fd;
+		bpf_map__name;
+		bpf_map__pin;
+		bpf_map__reuse_fd;
+		bpf_map__set_ifindex;
+		bpf_map__set_inner_map_fd;
+		bpf_map__unpin;
+		bpf_map_delete_elem;
+		bpf_map_get_fd_by_id;
+		bpf_map_get_next_id;
+		bpf_map_get_next_key;
+		bpf_map_lookup_and_delete_elem;
+		bpf_map_lookup_elem;
+		bpf_map_update_elem;
+		bpf_obj_get;
+		bpf_obj_get_info_by_fd;
+		bpf_obj_pin;
+		bpf_object__btf_fd;
+		bpf_object__close;
+		bpf_object__find_map_by_name;
+		bpf_object__kversion;
+		bpf_object__load;
+		bpf_object__name;
+		bpf_object__open;
+		bpf_object__pin;
+		bpf_object__pin_maps;
+		bpf_object__pin_programs;
+		bpf_object__unpin_maps;
+		bpf_object__unpin_programs;
+		bpf_prog_attach;
+		bpf_prog_detach;
+		bpf_prog_detach2;
+		bpf_prog_get_fd_by_id;
+		bpf_prog_get_next_id;
+		bpf_prog_query;
+		bpf_program__fd;
+		bpf_program__pin;
+		bpf_program__set_expected_attach_type;
+		bpf_program__set_ifindex;
+		bpf_program__set_type;
+		bpf_program__unload;
+		bpf_program__unpin;
+		bpf_prog_linfo__free;
+		bpf_prog_linfo__new;
+		bpf_prog_linfo__lfind_addr_func;
+		bpf_prog_linfo__lfind;
+		bpf_raw_tracepoint_open;
+		bpf_task_fd_query;
+		btf__fd;
+		btf__find_by_name;
+		btf__free;
+		btf__name_by_offset;
+		btf__new;
+		btf__resolve_size;
+		btf__resolve_type;
+		btf__type_by_id;
+		libbpf_attach_type_by_name;
+		libbpf_get_error;
+		libbpf_prog_type_by_name;
+		libbpf_set_print;
+		libbpf_strerror;
+	local:
+		*;
+};
+
+LIBBPF_0.0.2 {
+	global:
+		bpf_map_lookup_elem_flags;
+		bpf_object__btf;
+		bpf_object__find_map_fd_by_name;
+		btf__get_raw_data;
+		btf_ext__free;
+		btf_ext__get_raw_data;
+		btf_ext__new;
+} LIBBPF_0.0.1;
+
+LIBBPF_0.0.3 {
+	global:
+		bpf_map__is_internal;
+		bpf_map_freeze;
+} LIBBPF_0.0.2;
+
+LIBBPF_0.0.4 {
+	global:
+		bpf_link__destroy;
+		bpf_program__attach_kprobe;
+		bpf_program__attach_perf_event;
+		bpf_program__attach_raw_tracepoint;
+		bpf_program__attach_tracepoint;
+		bpf_program__attach_uprobe;
+		btf_dump__dump_type;
+		btf_dump__free;
+		btf__parse_elf;
+		libbpf_num_possible_cpus;
+		perf_buffer__free;
+		perf_buffer__poll;
+} LIBBPF_0.0.3;
+
+LIBBPF_0.0.5 {
+	global:
+		bpf_btf_get_next_id;
+} LIBBPF_0.0.4;
+
+LIBBPF_0.0.6 {
+	global:
+		bpf_map__get_pin_path;
+		bpf_map__is_pinned;
+		bpf_map__set_pin_path;
+		bpf_object__open_file;
+		bpf_object__open_mem;
+		bpf_program__attach_trace;
+		bpf_program__get_expected_attach_type;
+		bpf_program__get_type;
+		btf__find_by_name_kind;
+		libbpf_find_vmlinux_btf_id;
+} LIBBPF_0.0.5;
+
+LIBBPF_0.0.7 {
+	global:
+		btf_dump__emit_type_decl;
+		bpf_link__disconnect;
+		bpf_map__attach_struct_ops;
+		bpf_map_delete_batch;
+		bpf_map_lookup_and_delete_batch;
+		bpf_map_lookup_batch;
+		bpf_map_update_batch;
+		bpf_object__find_program_by_name;
+		bpf_object__attach_skeleton;
+		bpf_object__destroy_skeleton;
+		bpf_object__detach_skeleton;
+		bpf_object__load_skeleton;
+		bpf_object__open_skeleton;
+		bpf_program__attach;
+		bpf_program__name;
+		btf__align_of;
+		libbpf_find_kernel_btf;
+} LIBBPF_0.0.6;
+
+LIBBPF_0.0.8 {
+	global:
+		bpf_link__fd;
+		bpf_link__open;
+		bpf_link__pin;
+		bpf_link__pin_path;
+		bpf_link__unpin;
+		bpf_link__update_program;
+		bpf_link_create;
+		bpf_link_update;
+		bpf_map__set_initial_value;
+		bpf_prog_attach_opts;
+		bpf_program__attach_cgroup;
+		bpf_program__attach_lsm;
+		bpf_program__set_attach_target;
+} LIBBPF_0.0.7;
+
+LIBBPF_0.0.9 {
+	global:
+		bpf_enable_stats;
+		bpf_iter_create;
+		bpf_link_get_fd_by_id;
+		bpf_link_get_next_id;
+		bpf_program__attach_iter;
+		bpf_program__attach_netns;
+		perf_buffer__consume;
+		ring_buffer__add;
+		ring_buffer__consume;
+		ring_buffer__free;
+		ring_buffer__new;
+		ring_buffer__poll;
+} LIBBPF_0.0.8;
+
+LIBBPF_0.1.0 {
+	global:
+		bpf_link__detach;
+		bpf_link_detach;
+		bpf_map__ifindex;
+		bpf_map__key_size;
+		bpf_map__map_flags;
+		bpf_map__max_entries;
+		bpf_map__numa_node;
+		bpf_map__set_key_size;
+		bpf_map__set_map_flags;
+		bpf_map__set_max_entries;
+		bpf_map__set_numa_node;
+		bpf_map__set_type;
+		bpf_map__set_value_size;
+		bpf_map__type;
+		bpf_map__value_size;
+		bpf_program__attach_xdp;
+		bpf_program__autoload;
+		bpf_program__set_autoload;
+		btf__parse;
+		btf__parse_raw;
+		btf__pointer_size;
+		btf__set_fd;
+		btf__set_pointer_size;
+} LIBBPF_0.0.9;
+
+LIBBPF_0.2.0 {
+	global:
+		bpf_prog_bind_map;
+		bpf_prog_test_run_opts;
+		bpf_program__attach_freplace;
+		bpf_program__section_name;
+		btf__add_array;
+		btf__add_const;
+		btf__add_enum;
+		btf__add_enum_value;
+		btf__add_datasec;
+		btf__add_datasec_var_info;
+		btf__add_field;
+		btf__add_func;
+		btf__add_func_param;
+		btf__add_func_proto;
+		btf__add_fwd;
+		btf__add_int;
+		btf__add_ptr;
+		btf__add_restrict;
+		btf__add_str;
+		btf__add_struct;
+		btf__add_typedef;
+		btf__add_union;
+		btf__add_var;
+		btf__add_volatile;
+		btf__endianness;
+		btf__find_str;
+		btf__new_empty;
+		btf__set_endianness;
+		btf__str_by_offset;
+		perf_buffer__buffer_cnt;
+		perf_buffer__buffer_fd;
+		perf_buffer__epoll_fd;
+		perf_buffer__consume_buffer;
+} LIBBPF_0.1.0;
+
+LIBBPF_0.3.0 {
+	global:
+		btf__base_btf;
+		btf__parse_elf_split;
+		btf__parse_raw_split;
+		btf__parse_split;
+		btf__new_empty_split;
+		ring_buffer__epoll_fd;
+} LIBBPF_0.2.0;
+
+LIBBPF_0.4.0 {
+	global:
+		btf__add_float;
+		btf__add_type;
+		bpf_linker__add_file;
+		bpf_linker__finalize;
+		bpf_linker__free;
+		bpf_linker__new;
+		bpf_map__inner_map;
+		bpf_object__set_kversion;
+		bpf_tc_attach;
+		bpf_tc_detach;
+		bpf_tc_hook_create;
+		bpf_tc_hook_destroy;
+		bpf_tc_query;
+} LIBBPF_0.3.0;
+
+LIBBPF_0.5.0 {
+	global:
+		bpf_map__initial_value;
+		bpf_map__pin_path;
+		bpf_map_lookup_and_delete_elem_flags;
+		bpf_program__attach_kprobe_opts;
+		bpf_program__attach_perf_event_opts;
+		bpf_program__attach_tracepoint_opts;
+		bpf_program__attach_uprobe_opts;
+		bpf_object__gen_loader;
+		btf__load_from_kernel_by_id;
+		btf__load_from_kernel_by_id_split;
+		btf__load_into_kernel;
+		btf__load_module_btf;
+		btf__load_vmlinux_btf;
+		btf_dump__dump_type_data;
+		libbpf_set_strict_mode;
+} LIBBPF_0.4.0;
+
+LIBBPF_0.6.0 {
+	global:
+		bpf_map__map_extra;
+		bpf_map__set_map_extra;
+		bpf_map_create;
+		bpf_object__next_map;
+		bpf_object__next_program;
+		bpf_object__prev_map;
+		bpf_object__prev_program;
+		bpf_prog_load;
+		bpf_program__flags;
+		bpf_program__insn_cnt;
+		bpf_program__insns;
+		bpf_program__set_flags;
+		btf__add_btf;
+		btf__add_decl_tag;
+		btf__add_type_tag;
+		btf__dedup;
+		btf__raw_data;
+		btf__type_cnt;
+		btf_dump__new;
+		libbpf_major_version;
+		libbpf_minor_version;
+		libbpf_version_string;
+		perf_buffer__new;
+		perf_buffer__new_raw;
+} LIBBPF_0.5.0;
+
+LIBBPF_0.7.0 {
+	global:
+		bpf_btf_load;
+		bpf_program__expected_attach_type;
+		bpf_program__log_buf;
+		bpf_program__log_level;
+		bpf_program__set_log_buf;
+		bpf_program__set_log_level;
+		bpf_program__type;
+		bpf_xdp_attach;
+		bpf_xdp_detach;
+		bpf_xdp_query;
+		bpf_xdp_query_id;
+		libbpf_probe_bpf_helper;
+		libbpf_probe_bpf_map_type;
+		libbpf_probe_bpf_prog_type;
+		libbpf_set_memlock_rlim;
+} LIBBPF_0.6.0;
+
+LIBBPF_0.8.0 {
+	global:
+		bpf_map__autocreate;
+		bpf_map__get_next_key;
+		bpf_map__delete_elem;
+		bpf_map__lookup_and_delete_elem;
+		bpf_map__lookup_elem;
+		bpf_map__set_autocreate;
+		bpf_map__update_elem;
+		bpf_map_delete_elem_flags;
+		bpf_object__destroy_subskeleton;
+		bpf_object__open_subskeleton;
+		bpf_program__attach_kprobe_multi_opts;
+		bpf_program__attach_trace_opts;
+		bpf_program__attach_usdt;
+		bpf_program__set_insns;
+		libbpf_register_prog_handler;
+		libbpf_unregister_prog_handler;
+} LIBBPF_0.7.0;
+
+LIBBPF_1.0.0 {
+	global:
+		bpf_obj_get_opts;
+		bpf_prog_query_opts;
+		bpf_program__attach_ksyscall;
+		bpf_program__autoattach;
+		bpf_program__set_autoattach;
+		btf__add_enum64;
+		btf__add_enum64_value;
+		libbpf_bpf_attach_type_str;
+		libbpf_bpf_link_type_str;
+		libbpf_bpf_map_type_str;
+		libbpf_bpf_prog_type_str;
+		perf_buffer__buffer;
+} LIBBPF_0.8.0;
+
+LIBBPF_1.1.0 {
+	global:
+		bpf_btf_get_fd_by_id_opts;
+		bpf_link_get_fd_by_id_opts;
+		bpf_map_get_fd_by_id_opts;
+		bpf_prog_get_fd_by_id_opts;
+		user_ring_buffer__discard;
+		user_ring_buffer__free;
+		user_ring_buffer__new;
+		user_ring_buffer__reserve;
+		user_ring_buffer__reserve_blocking;
+		user_ring_buffer__submit;
+} LIBBPF_1.0.0;
+
+LIBBPF_1.2.0 {
+	global:
+		bpf_btf_get_info_by_fd;
+		bpf_link__update_map;
+		bpf_link_get_info_by_fd;
+		bpf_map_get_info_by_fd;
+		bpf_prog_get_info_by_fd;
+} LIBBPF_1.1.0;
+
+LIBBPF_1.3.0 {
+	global:
+		bpf_obj_pin_opts;
+		bpf_object__unpin;
+		bpf_prog_detach_opts;
+		bpf_program__attach_netfilter;
+		bpf_program__attach_netkit;
+		bpf_program__attach_tcx;
+		bpf_program__attach_uprobe_multi;
+		ring__avail_data_size;
+		ring__consume;
+		ring__consumer_pos;
+		ring__map_fd;
+		ring__producer_pos;
+		ring__size;
+		ring_buffer__ring;
+} LIBBPF_1.2.0;
+
+LIBBPF_1.4.0 {
+	global:
+		bpf_program__attach_raw_tracepoint_opts;
+		bpf_raw_tracepoint_open_opts;
+		bpf_token_create;
+		btf__new_split;
+		btf_ext__raw_data;
+} LIBBPF_1.3.0;
+
+LIBBPF_1.5.0 {
+	global:
+		btf__distill_base;
+		btf__relocate;
+		btf_ext__endianness;
+		btf_ext__set_endianness;
+		bpf_map__autoattach;
+		bpf_map__set_autoattach;
+		bpf_object__token_fd;
+		bpf_program__attach_sockmap;
+		ring__consume_n;
+		ring_buffer__consume_n;
+} LIBBPF_1.4.0;
+
+LIBBPF_1.6.0 {
+	global:
+		bpf_linker__add_buf;
+		bpf_linker__add_fd;
+		bpf_linker__new_fd;
+		bpf_object__prepare;
+		bpf_prog_stream_read;
+		bpf_program__attach_cgroup_opts;
+		bpf_program__func_info;
+		bpf_program__func_info_cnt;
+		bpf_program__line_info;
+		bpf_program__line_info_cnt;
+		btf__add_decl_attr;
+		btf__add_type_attr;
+} LIBBPF_1.5.0;
+
+LIBBPF_1.7.0 {
+	global:
+		bpf_map__set_exclusive_program;
+		bpf_map__exclusive_program;
+		bpf_prog_assoc_struct_ops;
+		bpf_program__assoc_struct_ops;
+		btf__permute;
+} LIBBPF_1.6.0;
+
+LIBBPF_1.8.0 {
+	global:
+		bpf_program__attach_tracing_multi;
+		bpf_program__clone;
+		btf__find_by_name_kind_own;
+		btf__new_empty_opts;
+} LIBBPF_1.7.0;
diff --git a/tools/lib/bpf/libbpf.pc.template b/tools/lib/bpf/libbpf.pc.template
new file mode 100644
index 000000000..b45ed534b
--- /dev/null
+++ b/tools/lib/bpf/libbpf.pc.template
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+prefix=@PREFIX@
+libdir=@LIBDIR@
+includedir=${prefix}/include
+
+Name: libbpf
+Description: BPF library
+Version: @VERSION@
+Libs: -L${libdir} -lbpf
+Requires.private: libelf zlib
+Cflags: -I${includedir}
diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h
new file mode 100644
index 000000000..8fe248e14
--- /dev/null
+++ b/tools/lib/bpf/libbpf_common.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * Common user-facing libbpf helpers.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+
+#ifndef __LIBBPF_LIBBPF_COMMON_H
+#define __LIBBPF_LIBBPF_COMMON_H
+
+#include <string.h>
+#include "libbpf_version.h"
+
+#ifndef LIBBPF_API
+#define LIBBPF_API __attribute__((visibility("default")))
+#endif
+
+#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))
+
+/* Mark a symbol as deprecated when libbpf version is >= {major}.{minor} */
+#define LIBBPF_DEPRECATED_SINCE(major, minor, msg)			    \
+	__LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor		    \
+		(LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg))
+
+#define __LIBBPF_CURRENT_VERSION_GEQ(major, minor)			    \
+	(LIBBPF_MAJOR_VERSION > (major) ||				    \
+	 (LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor)))
+
+/* Add checks for other versions below when planning deprecation of API symbols
+ * with the LIBBPF_DEPRECATED_SINCE macro.
+ */
+#if __LIBBPF_CURRENT_VERSION_GEQ(1, 0)
+#define __LIBBPF_MARK_DEPRECATED_1_0(X) X
+#else
+#define __LIBBPF_MARK_DEPRECATED_1_0(X)
+#endif
+
+/* This set of internal macros allows to do "function overloading" based on
+ * number of arguments provided by used in backwards-compatible way during the
+ * transition to libbpf 1.0
+ * It's ugly but necessary evil that will be cleaned up when we get to 1.0.
+ * See bpf_prog_load() overload for example.
+ */
+#define ___libbpf_cat(A, B) A ## B
+#define ___libbpf_select(NAME, NUM) ___libbpf_cat(NAME, NUM)
+#define ___libbpf_nth(_1, _2, _3, _4, _5, _6, N, ...) N
+#define ___libbpf_cnt(...) ___libbpf_nth(__VA_ARGS__, 6, 5, 4, 3, 2, 1)
+#define ___libbpf_overload(NAME, ...) ___libbpf_select(NAME, ___libbpf_cnt(__VA_ARGS__))(__VA_ARGS__)
+
+/* Helper macro to declare and initialize libbpf options struct
+ *
+ * This dance with uninitialized declaration, followed by memset to zero,
+ * followed by assignment using compound literal syntax is done to preserve
+ * ability to use a nice struct field initialization syntax and **hopefully**
+ * have all the padding bytes initialized to zero. It's not guaranteed though,
+ * when copying literal, that compiler won't copy garbage in literal's padding
+ * bytes, but that's the best way I've found and it seems to work in practice.
+ *
+ * Macro declares opts struct of given type and name, zero-initializes,
+ * including any extra padding, it with memset() and then assigns initial
+ * values provided by users in struct initializer-syntax as varargs.
+ */
+#define LIBBPF_OPTS(TYPE, NAME, ...)					    \
+	struct TYPE NAME = ({ 						    \
+		memset(&NAME, 0, sizeof(struct TYPE));			    \
+		(struct TYPE) {						    \
+			.sz = sizeof(struct TYPE),			    \
+			__VA_ARGS__					    \
+		};							    \
+	})
+
+/* Helper macro to clear and optionally reinitialize libbpf options struct
+ *
+ * Small helper macro to reset all fields and to reinitialize the common
+ * structure size member. Values provided by users in struct initializer-
+ * syntax as varargs can be provided as well to reinitialize options struct
+ * specific members.
+ */
+#define LIBBPF_OPTS_RESET(NAME, ...)					    \
+	do {								    \
+		typeof(NAME) ___##NAME = ({ 				    \
+			memset(&___##NAME, 0, sizeof(NAME));		    \
+			(typeof(NAME)) {				    \
+				.sz = sizeof(NAME),			    \
+				__VA_ARGS__				    \
+			};						    \
+		});							    \
+		memcpy(&NAME, &___##NAME, sizeof(NAME));		    \
+	} while (0)
+
+#endif /* __LIBBPF_LIBBPF_COMMON_H */
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
new file mode 100644
index 000000000..4c46d34fc
--- /dev/null
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -0,0 +1,774 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * Internal libbpf helpers.
+ *
+ * Copyright (c) 2019 Facebook
+ */
+
+#ifndef __LIBBPF_LIBBPF_INTERNAL_H
+#define __LIBBPF_LIBBPF_INTERNAL_H
+
+#include <stdlib.h>
+#include <byteswap.h>
+#include <limits.h>
+#include <errno.h>
+#include <linux/err.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <libelf.h>
+#include "relo_core.h"
+
+/* Android's libc doesn't support AT_EACCESS in faccessat() implementation
+ * ([0]), and just returns -EINVAL even if file exists and is accessible.
+ * See [1] for issues caused by this.
+ *
+ * So just redefine it to 0 on Android.
+ *
+ * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
+ * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
+ */
+#ifdef __ANDROID__
+#undef AT_EACCESS
+#define AT_EACCESS 0
+#endif
+
+/* make sure libbpf doesn't use kernel-only integer typedefs */
+#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+
+/* prevent accidental re-addition of reallocarray() */
+#pragma GCC poison reallocarray
+
+#include "libbpf.h"
+#include "btf.h"
+
+#ifndef EM_BPF
+#define EM_BPF 247
+#endif
+
+#ifndef R_BPF_64_64
+#define R_BPF_64_64 1
+#endif
+#ifndef R_BPF_64_ABS64
+#define R_BPF_64_ABS64 2
+#endif
+#ifndef R_BPF_64_ABS32
+#define R_BPF_64_ABS32 3
+#endif
+#ifndef R_BPF_64_32
+#define R_BPF_64_32 10
+#endif
+
+#ifndef SHT_LLVM_ADDRSIG
+#define SHT_LLVM_ADDRSIG 0x6FFF4C03
+#endif
+
+/* if libelf is old and doesn't support mmap(), fall back to read() */
+#ifndef ELF_C_READ_MMAP
+#define ELF_C_READ_MMAP ELF_C_READ
+#endif
+
+/* Older libelf all end up in this expression, for both 32 and 64 bit */
+#ifndef ELF64_ST_VISIBILITY
+#define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
+#endif
+
+#define JUMPTABLES_SEC ".jumptables"
+
+#define BTF_INFO_ENC(kind, kind_flag, vlen) \
+	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
+#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
+#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
+	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
+#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
+	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
+	BTF_INT_ENC(encoding, bits_offset, bits)
+#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
+#define BTF_PARAM_ENC(name, type) (name), (type)
+#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
+#define BTF_TYPE_FLOAT_ENC(name, sz) \
+	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
+#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
+	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
+#define BTF_TYPE_TYPE_TAG_ENC(value, type) \
+	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
+
+#ifndef likely
+#define likely(x) __builtin_expect(!!(x), 1)
+#endif
+#ifndef unlikely
+#define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
+#ifndef min
+# define min(x, y) ((x) < (y) ? (x) : (y))
+#endif
+#ifndef max
+# define max(x, y) ((x) < (y) ? (y) : (x))
+#endif
+#ifndef offsetofend
+# define offsetofend(TYPE, FIELD) \
+	(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
+#endif
+#ifndef __alias
+#define __alias(symbol) __attribute__((alias(#symbol)))
+#endif
+
+/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
+ * a string literal known at compilation time or char * pointer known only at
+ * runtime.
+ */
+#define str_has_pfx(str, pfx) \
+	(strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
+
+/* suffix check */
+static inline bool str_has_sfx(const char *str, const char *sfx)
+{
+	size_t str_len = strlen(str);
+	size_t sfx_len = strlen(sfx);
+
+	if (sfx_len > str_len)
+		return false;
+	return strcmp(str + str_len - sfx_len, sfx) == 0;
+}
+
+/* Symbol versioning is different between static and shared library.
+ * Properly versioned symbols are needed for shared library, but
+ * only the symbol of the new version is needed for static library.
+ * Starting with GNU C 10, use symver attribute instead of .symver assembler
+ * directive, which works better with GCC LTO builds.
+ */
+#if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
+
+#define DEFAULT_VERSION(internal_name, api_name, version) \
+	__attribute__((symver(#api_name "@@" #version)))
+#define COMPAT_VERSION(internal_name, api_name, version) \
+	__attribute__((symver(#api_name "@" #version)))
+
+#elif defined(SHARED)
+
+#define COMPAT_VERSION(internal_name, api_name, version) \
+	asm(".symver " #internal_name "," #api_name "@" #version);
+#define DEFAULT_VERSION(internal_name, api_name, version) \
+	asm(".symver " #internal_name "," #api_name "@@" #version);
+
+#else /* !SHARED */
+
+#define COMPAT_VERSION(internal_name, api_name, version)
+#define DEFAULT_VERSION(internal_name, api_name, version) \
+	extern typeof(internal_name) api_name \
+	__attribute__((alias(#internal_name)));
+
+#endif
+
+extern void libbpf_print(enum libbpf_print_level level,
+			 const char *format, ...)
+	__attribute__((format(printf, 2, 3)));
+
+#define __pr(level, fmt, ...)	\
+do {				\
+	libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__);	\
+} while (0)
+
+#define pr_warn(fmt, ...)	__pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
+#define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
+#define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
+
+/**
+ * @brief **libbpf_errstr()** returns string corresponding to numeric errno
+ * @param err negative numeric errno
+ * @return pointer to string representation of the errno, that is invalidated
+ * upon the next call.
+ */
+const char *libbpf_errstr(int err);
+
+#define errstr(err) libbpf_errstr(err)
+
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+struct bpf_link {
+	int (*detach)(struct bpf_link *link);
+	void (*dealloc)(struct bpf_link *link);
+	char *pin_path;		/* NULL, if not pinned */
+	int fd;			/* hook FD, -1 if not applicable */
+	bool disconnected;
+};
+
+/*
+ * Re-implement glibc's reallocarray() for libbpf internal-only use.
+ * reallocarray(), unfortunately, is not available in all versions of glibc,
+ * so requires extra feature detection and using reallocarray() stub from
+ * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
+ * build of libbpf unnecessarily and is just a maintenance burden. Instead,
+ * it's trivial to implement libbpf-specific internal version and use it
+ * throughout libbpf.
+ */
+static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
+{
+	size_t total;
+
+#if __has_builtin(__builtin_mul_overflow)
+	if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
+		return NULL;
+#else
+	if (size == 0 || nmemb > ULONG_MAX / size)
+		return NULL;
+	total = nmemb * size;
+#endif
+	return realloc(ptr, total);
+}
+
+/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
+ * is zero-terminated string no matter what (unless sz == 0, in which case
+ * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
+ * in what is returned. Given this is internal helper, it's trivial to extend
+ * this, when necessary. Use this instead of strncpy inside libbpf source code.
+ */
+static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
+{
+	size_t i;
+
+	if (sz == 0)
+		return;
+
+	sz--;
+	for (i = 0; i < sz && src[i]; i++)
+		dst[i] = src[i];
+	dst[i] = '\0';
+}
+
+__u32 get_kernel_version(void);
+
+struct btf;
+struct btf_type;
+
+struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
+const char *btf_kind_str(const struct btf_type *t);
+const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
+const struct btf_header *btf_header(const struct btf *btf);
+void btf_set_base_btf(struct btf *btf, const struct btf *base_btf);
+int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map);
+bool btf_type_is_traceable_func(const struct btf *btf, const struct btf_type *t);
+
+static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
+{
+	return (enum btf_func_linkage)(int)btf_vlen(t);
+}
+
+static inline __u32 btf_type_info(int kind, int vlen, int kflag)
+{
+	return (kflag << 31) | (kind << 24) | vlen;
+}
+
+enum map_def_parts {
+	MAP_DEF_MAP_TYPE	= 0x001,
+	MAP_DEF_KEY_TYPE	= 0x002,
+	MAP_DEF_KEY_SIZE	= 0x004,
+	MAP_DEF_VALUE_TYPE	= 0x008,
+	MAP_DEF_VALUE_SIZE	= 0x010,
+	MAP_DEF_MAX_ENTRIES	= 0x020,
+	MAP_DEF_MAP_FLAGS	= 0x040,
+	MAP_DEF_NUMA_NODE	= 0x080,
+	MAP_DEF_PINNING		= 0x100,
+	MAP_DEF_INNER_MAP	= 0x200,
+	MAP_DEF_MAP_EXTRA	= 0x400,
+
+	MAP_DEF_ALL		= 0x7ff, /* combination of all above */
+};
+
+struct btf_map_def {
+	enum map_def_parts parts;
+	__u32 map_type;
+	__u32 key_type_id;
+	__u32 key_size;
+	__u32 value_type_id;
+	__u32 value_size;
+	__u32 max_entries;
+	__u32 map_flags;
+	__u32 numa_node;
+	__u32 pinning;
+	__u64 map_extra;
+};
+
+int parse_btf_map_def(const char *map_name, struct btf *btf,
+		      const struct btf_type *def_t, bool strict,
+		      struct btf_map_def *map_def, struct btf_map_def *inner_def);
+
+void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
+		     size_t cur_cnt, size_t max_cnt, size_t add_cnt);
+int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
+
+static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
+{
+	while (len > 0) {
+		if (*p)
+			return false;
+		p++;
+		len--;
+	}
+	return true;
+}
+
+static inline bool libbpf_validate_opts(const char *opts,
+					size_t opts_sz, size_t user_sz,
+					const char *type_name)
+{
+	if (user_sz < sizeof(size_t)) {
+		pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
+		return false;
+	}
+	if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
+		pr_warn("%s has non-zero extra bytes\n", type_name);
+		return false;
+	}
+	return true;
+}
+
+#define OPTS_VALID(opts, type)						      \
+	(!(opts) || libbpf_validate_opts((const char *)opts,		      \
+					 offsetofend(struct type,	      \
+						     type##__last_field),     \
+					 (opts)->sz, #type))
+#define OPTS_HAS(opts, field) \
+	((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
+#define OPTS_GET(opts, field, fallback_value) \
+	(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
+#define OPTS_SET(opts, field, value)		\
+	do {					\
+		if (OPTS_HAS(opts, field))	\
+			(opts)->field = value;	\
+	} while (0)
+
+#define OPTS_ZEROED(opts, last_nonzero_field)				      \
+({									      \
+	ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field);     \
+	!(opts) || libbpf_is_mem_zeroed((const void *)opts + __off,	      \
+					(opts)->sz - __off);		      \
+})
+
+enum kern_feature_id {
+	/* v4.14: kernel support for program & map names. */
+	FEAT_PROG_NAME,
+	/* v5.2: kernel support for global data sections. */
+	FEAT_GLOBAL_DATA,
+	/* BTF support */
+	FEAT_BTF,
+	/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
+	FEAT_BTF_FUNC,
+	/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
+	FEAT_BTF_DATASEC,
+	/* BTF_FUNC_GLOBAL is supported */
+	FEAT_BTF_GLOBAL_FUNC,
+	/* BPF_F_MMAPABLE is supported for arrays */
+	FEAT_ARRAY_MMAP,
+	/* kernel support for expected_attach_type in BPF_PROG_LOAD */
+	FEAT_EXP_ATTACH_TYPE,
+	/* bpf_probe_read_{kernel,user}[_str] helpers */
+	FEAT_PROBE_READ_KERN,
+	/* BPF_PROG_BIND_MAP is supported */
+	FEAT_PROG_BIND_MAP,
+	/* Kernel support for module BTFs */
+	FEAT_MODULE_BTF,
+	/* BTF_KIND_FLOAT support */
+	FEAT_BTF_FLOAT,
+	/* BPF perf link support */
+	FEAT_PERF_LINK,
+	/* BTF_KIND_DECL_TAG support */
+	FEAT_BTF_DECL_TAG,
+	/* BTF_KIND_TYPE_TAG support */
+	FEAT_BTF_TYPE_TAG,
+	/* memcg-based accounting for BPF maps and progs */
+	FEAT_MEMCG_ACCOUNT,
+	/* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
+	FEAT_BPF_COOKIE,
+	/* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
+	FEAT_BTF_ENUM64,
+	/* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
+	FEAT_SYSCALL_WRAPPER,
+	/* BPF multi-uprobe link support */
+	FEAT_UPROBE_MULTI_LINK,
+	/* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */
+	FEAT_ARG_CTX_TAG,
+	/* Kernel supports '?' at the front of datasec names */
+	FEAT_BTF_QMARK_DATASEC,
+	/* Kernel supports LDIMM64 imm offsets past 512 MiB. */
+	FEAT_LDIMM64_FULL_RANGE_OFF,
+	/* Kernel supports uprobe syscall */
+	FEAT_UPROBE_SYSCALL,
+	/* Kernel supports BTF layout information */
+	FEAT_BTF_LAYOUT,
+	/* Kernel supports BPF syscall common attributes */
+	FEAT_BPF_SYSCALL_COMMON_ATTRS,
+	/* Kernel supports percpu data */
+	FEAT_PERCPU_DATA,
+	__FEAT_CNT,
+};
+
+enum kern_feature_result {
+	FEAT_UNKNOWN = 0,
+	FEAT_SUPPORTED = 1,
+	FEAT_MISSING = 2,
+};
+
+struct kern_feature_cache {
+	enum kern_feature_result res[__FEAT_CNT];
+	int token_fd;
+};
+
+bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
+bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
+void bpf_object_set_feat_cache(struct bpf_object *obj, struct kern_feature_cache *cache);
+
+int probe_kern_syscall_wrapper(int token_fd);
+int probe_memcg_account(int token_fd);
+int bump_rlimit_memlock(void);
+
+int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
+int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
+int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
+			 const char *str_sec, size_t str_len,
+			 int token_fd);
+int libbpf__load_raw_btf_hdr(const struct btf_header *hdr,
+			     const char *raw_types, const char *str_sec,
+			     const char *layout_sec, int token_fd);
+struct btf *bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *orig_btf);
+int btf_load_into_kernel(struct btf *btf,
+			 char *log_buf, size_t log_sz, __u32 log_level,
+			 int token_fd);
+struct btf *btf_load_from_kernel(__u32 id, struct btf *base_btf, int token_fd);
+
+struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
+void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
+				const char **prefix, int *kind);
+
+struct btf_ext_info {
+	/*
+	 * info points to the individual info section (e.g. func_info and
+	 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
+	 */
+	void *info;
+	__u32 rec_size;
+	__u32 len;
+	/* optional (maintained internally by libbpf) mapping between .BTF.ext
+	 * section and corresponding ELF section. This is used to join
+	 * information like CO-RE relocation records with corresponding BPF
+	 * programs defined in ELF sections
+	 */
+	__u32 *sec_idxs;
+	int sec_cnt;
+};
+
+#define for_each_btf_ext_sec(seg, sec)					\
+	for (sec = (seg)->info;						\
+	     (void *)sec < (seg)->info + (seg)->len;			\
+	     sec = (void *)sec + sizeof(struct btf_ext_info_sec) +	\
+		   (seg)->rec_size * sec->num_info)
+
+#define for_each_btf_ext_rec(seg, sec, i, rec)				\
+	for (i = 0, rec = (void *)&(sec)->data;				\
+	     i < (sec)->num_info;					\
+	     i++, rec = (void *)rec + (seg)->rec_size)
+
+/*
+ * The .BTF.ext ELF section layout defined as
+ *   struct btf_ext_header
+ *   func_info subsection
+ *
+ * The func_info subsection layout:
+ *   record size for struct bpf_func_info in the func_info subsection
+ *   struct btf_ext_info_sec for section #1
+ *   a list of bpf_func_info records for section #1
+ *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
+ *     but may not be identical
+ *   struct btf_ext_info_sec for section #2
+ *   a list of bpf_func_info records for section #2
+ *   ......
+ *
+ * Note that the bpf_func_info record size in .BTF.ext may not
+ * be the same as the one defined in include/uapi/linux/bpf.h.
+ * The loader should ensure that record_size meets minimum
+ * requirement and pass the record as is to the kernel. The
+ * kernel will handle the func_info properly based on its contents.
+ */
+struct btf_ext_header {
+	__u16	magic;
+	__u8	version;
+	__u8	flags;
+	__u32	hdr_len;
+
+	/* All offsets are in bytes relative to the end of this header */
+	__u32	func_info_off;
+	__u32	func_info_len;
+	__u32	line_info_off;
+	__u32	line_info_len;
+
+	/* optional part of .BTF.ext header */
+	__u32	core_relo_off;
+	__u32	core_relo_len;
+};
+
+struct btf_ext {
+	union {
+		struct btf_ext_header *hdr;
+		void *data;
+	};
+	void *data_swapped;
+	bool swapped_endian;
+	struct btf_ext_info func_info;
+	struct btf_ext_info line_info;
+	struct btf_ext_info core_relo_info;
+	__u32 data_size;
+};
+
+struct btf_ext_info_sec {
+	__u32	sec_name_off;
+	__u32	num_info;
+	/* Followed by num_info * record_size number of bytes */
+	__u8	data[];
+};
+
+/* The minimum bpf_func_info checked by the loader */
+struct bpf_func_info_min {
+	__u32   insn_off;
+	__u32   type_id;
+};
+
+/* The minimum bpf_line_info checked by the loader */
+struct bpf_line_info_min {
+	__u32	insn_off;
+	__u32	file_name_off;
+	__u32	line_off;
+	__u32	line_col;
+};
+
+/* Functions to byte-swap info records */
+
+typedef void (*info_rec_bswap_fn)(void *);
+
+static inline void bpf_func_info_bswap(struct bpf_func_info *i)
+{
+	i->insn_off = bswap_32(i->insn_off);
+	i->type_id = bswap_32(i->type_id);
+}
+
+static inline void bpf_line_info_bswap(struct bpf_line_info *i)
+{
+	i->insn_off = bswap_32(i->insn_off);
+	i->file_name_off = bswap_32(i->file_name_off);
+	i->line_off = bswap_32(i->line_off);
+	i->line_col = bswap_32(i->line_col);
+}
+
+static inline void bpf_core_relo_bswap(struct bpf_core_relo *i)
+{
+	i->insn_off = bswap_32(i->insn_off);
+	i->type_id = bswap_32(i->type_id);
+	i->access_str_off = bswap_32(i->access_str_off);
+	i->kind = bswap_32(i->kind);
+}
+
+enum btf_field_iter_kind {
+	BTF_FIELD_ITER_IDS,
+	BTF_FIELD_ITER_STRS,
+};
+
+struct btf_field_desc {
+	/* once-per-type offsets */
+	int t_off_cnt, t_offs[2];
+	/* member struct size, or zero, if no members */
+	int m_sz;
+	/* repeated per-member offsets */
+	int m_off_cnt, m_offs[1];
+};
+
+struct btf_field_iter {
+	struct btf_field_desc desc;
+	void *p;
+	int m_idx;
+	int off_idx;
+	int vlen;
+};
+
+int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind);
+__u32 *btf_field_iter_next(struct btf_field_iter *it);
+
+typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
+typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
+int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
+int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
+
+/* handle direct returned errors */
+static inline int libbpf_err(int ret)
+{
+	if (ret < 0)
+		errno = -ret;
+	return ret;
+}
+
+/* handle errno-based (e.g., syscall or libc) errors according to libbpf's
+ * strict mode settings
+ */
+static inline int libbpf_err_errno(int ret)
+{
+	/* errno is already assumed to be set on error */
+	return ret < 0 ? -errno : ret;
+}
+
+/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
+static inline void *libbpf_err_ptr(int err)
+{
+	/* set errno on error, this doesn't break anything */
+	errno = -err;
+	return NULL;
+}
+
+/* handle pointer-returning APIs' error handling */
+static inline void *libbpf_ptr(void *ret)
+{
+	/* set errno on error, this doesn't break anything */
+	if (IS_ERR(ret))
+		errno = -PTR_ERR(ret);
+
+	return IS_ERR(ret) ? NULL : ret;
+}
+
+static inline bool str_is_empty(const char *s)
+{
+	return !s || !s[0];
+}
+
+static inline bool is_ldimm64_insn(struct bpf_insn *insn)
+{
+	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
+}
+
+static inline void bpf_insn_bswap(struct bpf_insn *insn)
+{
+	__u8 tmp_reg = insn->dst_reg;
+
+	insn->dst_reg = insn->src_reg;
+	insn->src_reg = tmp_reg;
+	insn->off = bswap_16(insn->off);
+	insn->imm = bswap_32(insn->imm);
+}
+
+/* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
+ * Original FD is not closed or altered in any other way.
+ * Preserves original FD value, if it's invalid (negative).
+ */
+static inline int dup_good_fd(int fd)
+{
+	if (fd < 0)
+		return fd;
+	return fcntl(fd, F_DUPFD_CLOEXEC, 3);
+}
+
+/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
+ * Takes ownership of the fd passed in, and closes it if calling
+ * fcntl(fd, F_DUPFD_CLOEXEC, 3).
+ */
+static inline int ensure_good_fd(int fd)
+{
+	int old_fd = fd, saved_errno;
+
+	if (fd < 0)
+		return fd;
+	if (fd < 3) {
+		fd = dup_good_fd(fd);
+		saved_errno = errno;
+		close(old_fd);
+		errno = saved_errno;
+		if (fd < 0) {
+			pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
+			errno = saved_errno;
+		}
+	}
+	return fd;
+}
+
+static inline int sys_dup3(int oldfd, int newfd, int flags)
+{
+	return syscall(__NR_dup3, oldfd, newfd, flags);
+}
+
+/* Some versions of Android don't provide memfd_create() in their libc
+ * implementation, so avoid complications and just go straight to Linux
+ * syscall.
+ */
+static inline int sys_memfd_create(const char *name, unsigned flags)
+{
+	return syscall(__NR_memfd_create, name, flags);
+}
+
+/* Point *fixed_fd* to the same file that *tmp_fd* points to.
+ * Regardless of success, *tmp_fd* is closed.
+ * Whatever *fixed_fd* pointed to is closed silently.
+ */
+static inline int reuse_fd(int fixed_fd, int tmp_fd)
+{
+	int err;
+
+	err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC);
+	err = err < 0 ? -errno : 0;
+	close(tmp_fd); /* clean up temporary FD */
+	return err;
+}
+
+/* The following two functions are exposed to bpftool */
+int bpf_core_add_cands(struct bpf_core_cand *local_cand,
+		       size_t local_essent_len,
+		       const struct btf *targ_btf,
+		       const char *targ_btf_name,
+		       int targ_start_id,
+		       struct bpf_core_cand_list *cands);
+void bpf_core_free_cands(struct bpf_core_cand_list *cands);
+
+struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
+void usdt_manager_free(struct usdt_manager *man);
+struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
+					   const struct bpf_program *prog,
+					   pid_t pid, const char *path,
+					   const char *usdt_provider, const char *usdt_name,
+					   __u64 usdt_cookie);
+
+static inline bool is_pow_of_2(size_t x)
+{
+	return x && (x & (x - 1)) == 0;
+}
+
+static inline __u32 ror32(__u32 v, int bits)
+{
+	return (v >> bits) | (v << (32 - bits));
+}
+
+#define PROG_LOAD_ATTEMPTS 5
+int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
+
+bool glob_match(const char *str, const char *pat);
+
+long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
+long elf_find_func_offset_from_file(const char *binary_path, const char *name);
+
+struct elf_fd {
+	Elf *elf;
+	int fd;
+};
+
+int elf_open(const char *binary_path, struct elf_fd *elf_fd);
+void elf_close(struct elf_fd *elf_fd);
+
+int elf_resolve_syms_offsets(const char *binary_path, int cnt,
+			     const char **syms, unsigned long **poffsets,
+			     int st_type);
+int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
+				 unsigned long **poffsets, size_t *pcnt);
+
+int probe_fd(int fd);
+
+#define SHA256_DIGEST_LENGTH 32
+
+void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]);
+int probe_sys_bpf_ext(void);
+#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
diff --git a/tools/lib/bpf/libbpf_legacy.h b/tools/lib/bpf/libbpf_legacy.h
new file mode 100644
index 000000000..60b2600be
--- /dev/null
+++ b/tools/lib/bpf/libbpf_legacy.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * Libbpf legacy APIs (either discouraged or deprecated, as mentioned in [0])
+ *
+ *   [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY
+ *
+ * Copyright (C) 2021 Facebook
+ */
+#ifndef __LIBBPF_LEGACY_BPF_H
+#define __LIBBPF_LEGACY_BPF_H
+
+#include <linux/bpf.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include "libbpf_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* As of libbpf 1.0 libbpf_set_strict_mode() and enum libbpf_struct_mode have
+ * no effect. But they are left in libbpf_legacy.h so that applications that
+ * prepared for libbpf 1.0 before final release by using
+ * libbpf_set_strict_mode() still work with libbpf 1.0+ without any changes.
+ */
+enum libbpf_strict_mode {
+	/* Turn on all supported strict features of libbpf to simulate libbpf
+	 * v1.0 behavior.
+	 * This will be the default behavior in libbpf v1.0.
+	 */
+	LIBBPF_STRICT_ALL = 0xffffffff,
+
+	/*
+	 * Disable any libbpf 1.0 behaviors. This is the default before libbpf
+	 * v1.0. It won't be supported anymore in v1.0, please update your
+	 * code so that it handles LIBBPF_STRICT_ALL mode before libbpf v1.0.
+	 */
+	LIBBPF_STRICT_NONE = 0x00,
+	/*
+	 * Return NULL pointers on error, not ERR_PTR(err).
+	 * Additionally, libbpf also always sets errno to corresponding Exx
+	 * (positive) error code.
+	 */
+	LIBBPF_STRICT_CLEAN_PTRS = 0x01,
+	/*
+	 * Return actual error codes from low-level APIs directly, not just -1.
+	 * Additionally, libbpf also always sets errno to corresponding Exx
+	 * (positive) error code.
+	 */
+	LIBBPF_STRICT_DIRECT_ERRS = 0x02,
+	/*
+	 * Enforce strict BPF program section (SEC()) names.
+	 * E.g., while prefiously SEC("xdp_whatever") or SEC("perf_event_blah") were
+	 * allowed, with LIBBPF_STRICT_SEC_PREFIX this will become
+	 * unrecognized by libbpf and would have to be just SEC("xdp") and
+	 * SEC("xdp") and SEC("perf_event").
+	 *
+	 * Note, in this mode the program pin path will be based on the
+	 * function name instead of section name.
+	 *
+	 * Additionally, routines in the .text section are always considered
+	 * sub-programs. Legacy behavior allows for a single routine in .text
+	 * to be a program.
+	 */
+	LIBBPF_STRICT_SEC_NAME = 0x04,
+	/*
+	 * Disable the global 'bpf_objects_list'. Maintaining this list adds
+	 * a race condition to bpf_object__open() and bpf_object__close().
+	 * Clients can maintain it on their own if it is valuable for them.
+	 */
+	LIBBPF_STRICT_NO_OBJECT_LIST = 0x08,
+	/*
+	 * Automatically bump RLIMIT_MEMLOCK using setrlimit() before the
+	 * first BPF program or map creation operation. This is done only if
+	 * kernel is too old to support memcg-based memory accounting for BPF
+	 * subsystem. By default, RLIMIT_MEMLOCK limit is set to RLIM_INFINITY,
+	 * but it can be overridden with libbpf_set_memlock_rlim() API.
+	 * Note that libbpf_set_memlock_rlim() needs to be called before
+	 * the very first bpf_prog_load(), bpf_map_create() or bpf_object__load()
+	 * operation.
+	 */
+	LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK = 0x10,
+	/*
+	 * Error out on any SEC("maps") map definition, which are deprecated
+	 * in favor of BTF-defined map definitions in SEC(".maps").
+	 */
+	LIBBPF_STRICT_MAP_DEFINITIONS = 0x20,
+
+	__LIBBPF_STRICT_LAST,
+};
+
+LIBBPF_API int libbpf_set_strict_mode(enum libbpf_strict_mode mode);
+
+/**
+ * @brief **libbpf_get_error()** extracts the error code from the passed
+ * pointer
+ * @param ptr pointer returned from libbpf API function
+ * @return error code; or 0 if no error occurred
+ *
+ * Note, as of libbpf 1.0 this function is not necessary and not recommended
+ * to be used. Libbpf doesn't return error code embedded into the pointer
+ * itself. Instead, NULL is returned on error and error code is passed through
+ * thread-local errno variable. **libbpf_get_error()** is just returning -errno
+ * value if it receives NULL, which is correct only if errno hasn't been
+ * modified between libbpf API call and corresponding **libbpf_get_error()**
+ * call. Prefer to check return for NULL and use errno directly.
+ *
+ * This API is left in libbpf 1.0 to allow applications that were 1.0-ready
+ * before final libbpf 1.0 without needing to change them.
+ */
+LIBBPF_API long libbpf_get_error(const void *ptr);
+
+#define DECLARE_LIBBPF_OPTS LIBBPF_OPTS
+
+/* "Discouraged" APIs which don't follow consistent libbpf naming patterns.
+ * They are normally a trivial aliases or wrappers for proper APIs and are
+ * left to minimize unnecessary disruption for users of libbpf. But they
+ * shouldn't be used going forward.
+ */
+
+struct bpf_program;
+struct bpf_map;
+struct btf;
+struct btf_ext;
+
+LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
+
+LIBBPF_API enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog);
+LIBBPF_API enum bpf_attach_type bpf_program__get_expected_attach_type(const struct bpf_program *prog);
+LIBBPF_API const char *bpf_map__get_pin_path(const struct bpf_map *map);
+LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
+LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* __LIBBPF_LEGACY_BPF_H */
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
new file mode 100644
index 000000000..e40819465
--- /dev/null
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2019 Netronome Systems, Inc. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <sys/utsname.h>
+
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/version.h>
+
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+/* On Ubuntu LINUX_VERSION_CODE doesn't correspond to info.release,
+ * but Ubuntu provides /proc/version_signature file, as described at
+ * https://ubuntu.com/kernel, with an example contents below, which we
+ * can use to get a proper LINUX_VERSION_CODE.
+ *
+ *   Ubuntu 5.4.0-12.15-generic 5.4.8
+ *
+ * In the above, 5.4.8 is what kernel is actually expecting, while
+ * uname() call will return 5.4.0 in info.release.
+ */
+static __u32 get_ubuntu_kernel_version(void)
+{
+	const char *ubuntu_kver_file = "/proc/version_signature";
+	__u32 major, minor, patch;
+	int ret;
+	FILE *f;
+
+	if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0)
+		return 0;
+
+	f = fopen(ubuntu_kver_file, "re");
+	if (!f)
+		return 0;
+
+	ret = fscanf(f, "%*s %*s %u.%u.%u\n", &major, &minor, &patch);
+	fclose(f);
+	if (ret != 3)
+		return 0;
+
+	return KERNEL_VERSION(major, minor, patch);
+}
+
+/* On Debian LINUX_VERSION_CODE doesn't correspond to info.release.
+ * Instead, it is provided in info.version. An example content of
+ * Debian 10 looks like the below.
+ *
+ *   utsname::release   4.19.0-22-amd64
+ *   utsname::version   #1 SMP Debian 4.19.260-1 (2022-09-29)
+ *
+ * In the above, 4.19.260 is what kernel is actually expecting, while
+ * uname() call will return 4.19.0 in info.release.
+ */
+static __u32 get_debian_kernel_version(struct utsname *info)
+{
+	__u32 major, minor, patch;
+	char *p;
+
+	p = strstr(info->version, "Debian ");
+	if (!p) {
+		/* This is not a Debian kernel. */
+		return 0;
+	}
+
+	if (sscanf(p, "Debian %u.%u.%u", &major, &minor, &patch) != 3)
+		return 0;
+
+	return KERNEL_VERSION(major, minor, patch);
+}
+
+__u32 get_kernel_version(void)
+{
+	__u32 major, minor, patch, version;
+	struct utsname info;
+
+	/* Check if this is an Ubuntu kernel. */
+	version = get_ubuntu_kernel_version();
+	if (version != 0)
+		return version;
+
+	uname(&info);
+
+	/* Check if this is a Debian kernel. */
+	version = get_debian_kernel_version(&info);
+	if (version != 0)
+		return version;
+
+	if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
+		return 0;
+
+	return KERNEL_VERSION(major, minor, patch);
+}
+
+static int probe_prog_load(enum bpf_prog_type prog_type,
+			   const struct bpf_insn *insns, size_t insns_cnt,
+			   char *log_buf, size_t log_buf_sz)
+{
+	LIBBPF_OPTS(bpf_prog_load_opts, opts,
+		.log_buf = log_buf,
+		.log_size = log_buf_sz,
+		.log_level = log_buf ? 1 : 0,
+	);
+	int fd, err, exp_err = 0;
+	const char *exp_msg = NULL;
+	char buf[4096];
+
+	switch (prog_type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+		opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
+		break;
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
+		break;
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		opts.expected_attach_type = BPF_SK_LOOKUP;
+		break;
+	case BPF_PROG_TYPE_KPROBE:
+		opts.kern_version = get_kernel_version();
+		break;
+	case BPF_PROG_TYPE_LIRC_MODE2:
+		opts.expected_attach_type = BPF_LIRC_MODE2;
+		break;
+	case BPF_PROG_TYPE_TRACING:
+	case BPF_PROG_TYPE_LSM:
+		opts.log_buf = buf;
+		opts.log_size = sizeof(buf);
+		opts.log_level = 1;
+		if (prog_type == BPF_PROG_TYPE_TRACING)
+			opts.expected_attach_type = BPF_TRACE_FENTRY;
+		else
+			opts.expected_attach_type = BPF_MODIFY_RETURN;
+		opts.attach_btf_id = 1;
+
+		exp_err = -EINVAL;
+		exp_msg = "attach_btf_id 1 is not a function";
+		break;
+	case BPF_PROG_TYPE_EXT:
+		opts.log_buf = buf;
+		opts.log_size = sizeof(buf);
+		opts.log_level = 1;
+		opts.attach_btf_id = 1;
+
+		exp_err = -EINVAL;
+		exp_msg = "Cannot replace kernel functions";
+		break;
+	case BPF_PROG_TYPE_SYSCALL:
+		opts.prog_flags = BPF_F_SLEEPABLE;
+		break;
+	case BPF_PROG_TYPE_STRUCT_OPS:
+		exp_err = -524; /* -ENOTSUPP */
+		break;
+	case BPF_PROG_TYPE_UNSPEC:
+	case BPF_PROG_TYPE_SOCKET_FILTER:
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_TRACEPOINT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_PERF_EVENT:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_LWT_IN:
+	case BPF_PROG_TYPE_LWT_OUT:
+	case BPF_PROG_TYPE_LWT_XMIT:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_SK_SKB:
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_SK_MSG:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+		break;
+	case BPF_PROG_TYPE_NETFILTER:
+		opts.expected_attach_type = BPF_NETFILTER;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts);
+	err = -errno;
+	if (fd >= 0)
+		close(fd);
+	if (exp_err) {
+		if (fd >= 0 || err != exp_err)
+			return 0;
+		if (exp_msg && !strstr(buf, exp_msg))
+			return 0;
+		return 1;
+	}
+	return fd >= 0 ? 1 : 0;
+}
+
+int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts)
+{
+	struct bpf_insn insns[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN()
+	};
+	const size_t insn_cnt = ARRAY_SIZE(insns);
+	int ret;
+
+	if (opts)
+		return libbpf_err(-EINVAL);
+
+	ret = probe_prog_load(prog_type, insns, insn_cnt, NULL, 0);
+	return libbpf_err(ret);
+}
+
+int libbpf__load_raw_btf_hdr(const struct btf_header *hdr, const char *raw_types,
+			     const char *str_sec, const char *layout_sec,
+			     int token_fd)
+{
+	LIBBPF_OPTS(bpf_btf_load_opts, opts,
+		.token_fd = token_fd,
+		.btf_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	int btf_fd, btf_len;
+	__u8 *raw_btf;
+
+	btf_len = hdr->hdr_len + hdr->type_off + hdr->type_len + hdr->str_len + hdr->layout_len;
+	raw_btf = malloc(btf_len);
+	if (!raw_btf)
+		return -ENOMEM;
+
+	memcpy(raw_btf, hdr, sizeof(*hdr));
+	memcpy(raw_btf + hdr->hdr_len + hdr->type_off, raw_types, hdr->type_len);
+	memcpy(raw_btf + hdr->hdr_len + hdr->str_off, str_sec, hdr->str_len);
+	if (layout_sec)
+		memcpy(raw_btf + hdr->hdr_len + hdr->layout_off, layout_sec, hdr->layout_len);
+
+	btf_fd = bpf_btf_load(raw_btf, btf_len, &opts);
+
+	free(raw_btf);
+	return btf_fd;
+}
+
+int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
+			 const char *str_sec, size_t str_len,
+			 int token_fd)
+{
+	struct btf_header hdr = {
+		.magic = BTF_MAGIC,
+		.version = BTF_VERSION,
+		.hdr_len = sizeof(struct btf_header),
+		.type_len = types_len,
+		.str_off = types_len,
+		.str_len = str_len,
+	};
+
+	return libbpf__load_raw_btf_hdr(&hdr, raw_types, str_sec, NULL, token_fd);
+}
+
+static int load_local_storage_btf(void)
+{
+	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
+	/* struct bpf_spin_lock {
+	 *   int val;
+	 * };
+	 * struct val {
+	 *   int cnt;
+	 *   struct bpf_spin_lock l;
+	 * };
+	 */
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* struct bpf_spin_lock */                      /* [2] */
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
+		BTF_MEMBER_ENC(15, 1, 0), /* int val; */
+		/* struct val */                                /* [3] */
+		BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
+		BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
+		BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
+	};
+
+	return libbpf__load_raw_btf((char *)types, sizeof(types),
+				     strs, sizeof(strs), 0);
+}
+
+static int probe_map_create(enum bpf_map_type map_type)
+{
+	LIBBPF_OPTS(bpf_map_create_opts, opts);
+	int key_size, value_size, max_entries;
+	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
+	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;
+
+	key_size	= sizeof(__u32);
+	value_size	= sizeof(__u32);
+	max_entries	= 1;
+
+	switch (map_type) {
+	case BPF_MAP_TYPE_STACK_TRACE:
+		value_size	= sizeof(__u64);
+		break;
+	case BPF_MAP_TYPE_LPM_TRIE:
+		key_size	= sizeof(__u64);
+		value_size	= sizeof(__u64);
+		opts.map_flags	= BPF_F_NO_PREALLOC;
+		break;
+	case BPF_MAP_TYPE_RHASH:
+		opts.map_flags	= BPF_F_NO_PREALLOC;
+		break;
+	case BPF_MAP_TYPE_CGROUP_STORAGE:
+	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
+		key_size	= sizeof(struct bpf_cgroup_storage_key);
+		value_size	= sizeof(__u64);
+		max_entries	= 0;
+		break;
+	case BPF_MAP_TYPE_QUEUE:
+	case BPF_MAP_TYPE_STACK:
+		key_size	= 0;
+		break;
+	case BPF_MAP_TYPE_SK_STORAGE:
+	case BPF_MAP_TYPE_INODE_STORAGE:
+	case BPF_MAP_TYPE_TASK_STORAGE:
+	case BPF_MAP_TYPE_CGRP_STORAGE:
+		btf_key_type_id = 1;
+		btf_value_type_id = 3;
+		value_size = 8;
+		max_entries = 0;
+		opts.map_flags = BPF_F_NO_PREALLOC;
+		btf_fd = load_local_storage_btf();
+		if (btf_fd < 0)
+			return btf_fd;
+		break;
+	case BPF_MAP_TYPE_RINGBUF:
+	case BPF_MAP_TYPE_USER_RINGBUF:
+		key_size = 0;
+		value_size = 0;
+		max_entries = sysconf(_SC_PAGE_SIZE);
+		break;
+	case BPF_MAP_TYPE_STRUCT_OPS:
+		/* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
+		opts.btf_vmlinux_value_type_id = 1;
+		opts.value_type_btf_obj_fd = -1;
+		exp_err = -524; /* -ENOTSUPP */
+		break;
+	case BPF_MAP_TYPE_BLOOM_FILTER:
+		key_size = 0;
+		max_entries = 1;
+		break;
+	case BPF_MAP_TYPE_ARENA:
+		key_size	= 0;
+		value_size	= 0;
+		max_entries	= 1; /* one page */
+		opts.map_extra	= 0; /* can mmap() at any address */
+		opts.map_flags	= BPF_F_MMAPABLE;
+		break;
+	case BPF_MAP_TYPE_HASH:
+	case BPF_MAP_TYPE_ARRAY:
+	case BPF_MAP_TYPE_PROG_ARRAY:
+	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
+	case BPF_MAP_TYPE_PERCPU_HASH:
+	case BPF_MAP_TYPE_PERCPU_ARRAY:
+	case BPF_MAP_TYPE_CGROUP_ARRAY:
+	case BPF_MAP_TYPE_LRU_HASH:
+	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+	case BPF_MAP_TYPE_DEVMAP:
+	case BPF_MAP_TYPE_DEVMAP_HASH:
+	case BPF_MAP_TYPE_SOCKMAP:
+	case BPF_MAP_TYPE_CPUMAP:
+	case BPF_MAP_TYPE_XSKMAP:
+	case BPF_MAP_TYPE_SOCKHASH:
+	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
+		break;
+	case BPF_MAP_TYPE_INSN_ARRAY:
+		key_size	= sizeof(__u32);
+		value_size	= sizeof(struct bpf_insn_array_value);
+		break;
+	case BPF_MAP_TYPE_UNSPEC:
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
+	    map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
+		fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
+					  sizeof(__u32), sizeof(__u32), 1, NULL);
+		if (fd_inner < 0)
+			goto cleanup;
+
+		opts.inner_map_fd = fd_inner;
+	}
+
+	if (btf_fd >= 0) {
+		opts.btf_fd = btf_fd;
+		opts.btf_key_type_id = btf_key_type_id;
+		opts.btf_value_type_id = btf_value_type_id;
+	}
+
+	fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts);
+	err = -errno;
+
+cleanup:
+	if (fd >= 0)
+		close(fd);
+	if (fd_inner >= 0)
+		close(fd_inner);
+	if (btf_fd >= 0)
+		close(btf_fd);
+
+	if (exp_err)
+		return fd < 0 && err == exp_err ? 1 : 0;
+	else
+		return fd >= 0 ? 1 : 0;
+}
+
+int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts)
+{
+	int ret;
+
+	if (opts)
+		return libbpf_err(-EINVAL);
+
+	ret = probe_map_create(map_type);
+	return libbpf_err(ret);
+}
+
+int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type, enum bpf_func_id helper_id,
+			    const void *opts)
+{
+	struct bpf_insn insns[] = {
+		BPF_EMIT_CALL((__u32)helper_id),
+		BPF_EXIT_INSN(),
+	};
+	const size_t insn_cnt = ARRAY_SIZE(insns);
+	char buf[4096];
+	int ret;
+
+	if (opts)
+		return libbpf_err(-EINVAL);
+
+	/* we can't successfully load all prog types to check for BPF helper
+	 * support, so bail out with -EOPNOTSUPP error
+	 */
+	switch (prog_type) {
+	case BPF_PROG_TYPE_TRACING:
+	case BPF_PROG_TYPE_EXT:
+	case BPF_PROG_TYPE_LSM:
+	case BPF_PROG_TYPE_STRUCT_OPS:
+		return -EOPNOTSUPP;
+	default:
+		break;
+	}
+
+	buf[0] = '\0';
+	ret = probe_prog_load(prog_type, insns, insn_cnt, buf, sizeof(buf));
+	if (ret < 0)
+		return libbpf_err(ret);
+
+	/* If BPF verifier doesn't recognize BPF helper ID (enum bpf_func_id)
+	 * at all, it will emit something like "invalid func unknown#181".
+	 * If BPF verifier recognizes BPF helper but it's not supported for
+	 * given BPF program type, it will emit "unknown func bpf_sys_bpf#166"
+	 * or "program of this type cannot use helper bpf_sys_bpf#166".
+	 * In both cases, provided combination of BPF program type and BPF
+	 * helper is not supported by the kernel.
+	 * In all other cases, probe_prog_load() above will either succeed (e.g.,
+	 * because BPF helper happens to accept no input arguments or it
+	 * accepts one input argument and initial PTR_TO_CTX is fine for
+	 * that), or we'll get some more specific BPF verifier error about
+	 * some unsatisfied conditions.
+	 */
+	if (ret == 0 && (strstr(buf, "invalid func ") || strstr(buf, "unknown func ") ||
+			 strstr(buf, "program of this type cannot use helper ")))
+		return 0;
+	return 1; /* assume supported */
+}
diff --git a/tools/lib/bpf/libbpf_utils.c b/tools/lib/bpf/libbpf_utils.c
new file mode 100644
index 000000000..ac3beae54
--- /dev/null
+++ b/tools/lib/bpf/libbpf_utils.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ * Copyright (C) 2017 Nicira, Inc.
+ */
+
+#undef _GNU_SOURCE
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <linux/kernel.h>
+
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+#ifndef ENOTSUPP
+#define ENOTSUPP	524
+#endif
+
+/* make sure libbpf doesn't use kernel-only integer typedefs */
+#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+
+#define ERRNO_OFFSET(e)		((e) - __LIBBPF_ERRNO__START)
+#define ERRCODE_OFFSET(c)	ERRNO_OFFSET(LIBBPF_ERRNO__##c)
+#define NR_ERRNO	(__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
+
+static const char *libbpf_strerror_table[NR_ERRNO] = {
+	[ERRCODE_OFFSET(LIBELF)]	= "Something wrong in libelf",
+	[ERRCODE_OFFSET(FORMAT)]	= "BPF object format invalid",
+	[ERRCODE_OFFSET(KVERSION)]	= "'version' section incorrect or lost",
+	[ERRCODE_OFFSET(ENDIAN)]	= "Endian mismatch",
+	[ERRCODE_OFFSET(INTERNAL)]	= "Internal error in libbpf",
+	[ERRCODE_OFFSET(RELOC)]		= "Relocation failed",
+	[ERRCODE_OFFSET(VERIFY)]	= "Kernel verifier blocks program loading",
+	[ERRCODE_OFFSET(PROG2BIG)]	= "Program too big",
+	[ERRCODE_OFFSET(KVER)]		= "Incorrect kernel version",
+	[ERRCODE_OFFSET(PROGTYPE)]	= "Kernel doesn't support this program type",
+	[ERRCODE_OFFSET(WRNGPID)]	= "Wrong pid in netlink message",
+	[ERRCODE_OFFSET(INVSEQ)]	= "Invalid netlink sequence",
+	[ERRCODE_OFFSET(NLPARSE)]	= "Incorrect netlink message parsing",
+};
+
+int libbpf_strerror(int err, char *buf, size_t size)
+{
+	int ret;
+
+	if (!buf || !size)
+		return libbpf_err(-EINVAL);
+
+	err = err > 0 ? err : -err;
+
+	if (err < __LIBBPF_ERRNO__START) {
+		ret = strerror_r(err, buf, size);
+		buf[size - 1] = '\0';
+		return libbpf_err_errno(ret);
+	}
+
+	if (err < __LIBBPF_ERRNO__END) {
+		const char *msg;
+
+		msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
+		ret = snprintf(buf, size, "%s", msg);
+		buf[size - 1] = '\0';
+		/* The length of the buf and msg is positive.
+		 * A negative number may be returned only when the
+		 * size exceeds INT_MAX. Not likely to appear.
+		 */
+		if (ret >= size)
+			return libbpf_err(-ERANGE);
+		return 0;
+	}
+
+	ret = snprintf(buf, size, "Unknown libbpf error %d", err);
+	buf[size - 1] = '\0';
+	if (ret >= size)
+		return libbpf_err(-ERANGE);
+	return libbpf_err(-ENOENT);
+}
+
+const char *libbpf_errstr(int err)
+{
+	static __thread char buf[12];
+
+	if (err > 0)
+		err = -err;
+
+	switch (err) {
+	case -E2BIG:		return "-E2BIG";
+	case -EACCES:		return "-EACCES";
+	case -EADDRINUSE:	return "-EADDRINUSE";
+	case -EADDRNOTAVAIL:	return "-EADDRNOTAVAIL";
+	case -EAGAIN:		return "-EAGAIN";
+	case -EALREADY:		return "-EALREADY";
+	case -EBADF:		return "-EBADF";
+	case -EBADFD:		return "-EBADFD";
+	case -EBUSY:		return "-EBUSY";
+	case -ECANCELED:	return "-ECANCELED";
+	case -ECHILD:		return "-ECHILD";
+	case -EDEADLK:		return "-EDEADLK";
+	case -EDOM:		return "-EDOM";
+	case -EEXIST:		return "-EEXIST";
+	case -EFAULT:		return "-EFAULT";
+	case -EFBIG:		return "-EFBIG";
+	case -EILSEQ:		return "-EILSEQ";
+	case -EINPROGRESS:	return "-EINPROGRESS";
+	case -EINTR:		return "-EINTR";
+	case -EINVAL:		return "-EINVAL";
+	case -EIO:		return "-EIO";
+	case -EISDIR:		return "-EISDIR";
+	case -ELOOP:		return "-ELOOP";
+	case -EMFILE:		return "-EMFILE";
+	case -EMLINK:		return "-EMLINK";
+	case -EMSGSIZE:		return "-EMSGSIZE";
+	case -ENAMETOOLONG:	return "-ENAMETOOLONG";
+	case -ENFILE:		return "-ENFILE";
+	case -ENODATA:		return "-ENODATA";
+	case -ENODEV:		return "-ENODEV";
+	case -ENOENT:		return "-ENOENT";
+	case -ENOEXEC:		return "-ENOEXEC";
+	case -ENOLINK:		return "-ENOLINK";
+	case -ENOMEM:		return "-ENOMEM";
+	case -ENOSPC:		return "-ENOSPC";
+	case -ENOTBLK:		return "-ENOTBLK";
+	case -ENOTDIR:		return "-ENOTDIR";
+	case -ENOTSUPP:		return "-ENOTSUPP";
+	case -ENOTTY:		return "-ENOTTY";
+	case -ENXIO:		return "-ENXIO";
+	case -EOPNOTSUPP:	return "-EOPNOTSUPP";
+	case -EOVERFLOW:	return "-EOVERFLOW";
+	case -EPERM:		return "-EPERM";
+	case -EPIPE:		return "-EPIPE";
+	case -EPROTO:		return "-EPROTO";
+	case -EPROTONOSUPPORT:	return "-EPROTONOSUPPORT";
+	case -ERANGE:		return "-ERANGE";
+	case -EROFS:		return "-EROFS";
+	case -ESPIPE:		return "-ESPIPE";
+	case -ESRCH:		return "-ESRCH";
+	case -ETXTBSY:		return "-ETXTBSY";
+	case -EUCLEAN:		return "-EUCLEAN";
+	case -EXDEV:		return "-EXDEV";
+	default:
+		snprintf(buf, sizeof(buf), "%d", err);
+		return buf;
+	}
+}
+
+static inline __u32 get_unaligned_be32(const void *p)
+{
+	__be32 val;
+
+	memcpy(&val, p, sizeof(val));
+	return be32_to_cpu(val);
+}
+
+static inline void put_unaligned_be32(__u32 val, void *p)
+{
+	__be32 be_val = cpu_to_be32(val);
+
+	memcpy(p, &be_val, sizeof(be_val));
+}
+
+#define SHA256_BLOCK_LENGTH 64
+#define Ch(x, y, z) (((x) & (y)) ^ (~(x) & (z)))
+#define Maj(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
+#define Sigma_0(x) (ror32((x), 2) ^ ror32((x), 13) ^ ror32((x), 22))
+#define Sigma_1(x) (ror32((x), 6) ^ ror32((x), 11) ^ ror32((x), 25))
+#define sigma_0(x) (ror32((x), 7) ^ ror32((x), 18) ^ ((x) >> 3))
+#define sigma_1(x) (ror32((x), 17) ^ ror32((x), 19) ^ ((x) >> 10))
+
+static const __u32 sha256_K[64] = {
+	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+	0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+	0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+	0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+	0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+	0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
+};
+
+#define SHA256_ROUND(i, a, b, c, d, e, f, g, h)                                \
+	{                                                                      \
+		__u32 tmp = h + Sigma_1(e) + Ch(e, f, g) + sha256_K[i] + w[i]; \
+		d += tmp;                                                      \
+		h = tmp + Sigma_0(a) + Maj(a, b, c);                           \
+	}
+
+static void sha256_blocks(__u32 state[8], const __u8 *data, size_t nblocks)
+{
+	while (nblocks--) {
+		__u32 a = state[0];
+		__u32 b = state[1];
+		__u32 c = state[2];
+		__u32 d = state[3];
+		__u32 e = state[4];
+		__u32 f = state[5];
+		__u32 g = state[6];
+		__u32 h = state[7];
+		__u32 w[64];
+		int i;
+
+		for (i = 0; i < 16; i++)
+			w[i] = get_unaligned_be32(&data[4 * i]);
+		for (; i < ARRAY_SIZE(w); i++)
+			w[i] = sigma_1(w[i - 2]) + w[i - 7] +
+			       sigma_0(w[i - 15]) + w[i - 16];
+		for (i = 0; i < ARRAY_SIZE(w); i += 8) {
+			SHA256_ROUND(i + 0, a, b, c, d, e, f, g, h);
+			SHA256_ROUND(i + 1, h, a, b, c, d, e, f, g);
+			SHA256_ROUND(i + 2, g, h, a, b, c, d, e, f);
+			SHA256_ROUND(i + 3, f, g, h, a, b, c, d, e);
+			SHA256_ROUND(i + 4, e, f, g, h, a, b, c, d);
+			SHA256_ROUND(i + 5, d, e, f, g, h, a, b, c);
+			SHA256_ROUND(i + 6, c, d, e, f, g, h, a, b);
+			SHA256_ROUND(i + 7, b, c, d, e, f, g, h, a);
+		}
+		state[0] += a;
+		state[1] += b;
+		state[2] += c;
+		state[3] += d;
+		state[4] += e;
+		state[5] += f;
+		state[6] += g;
+		state[7] += h;
+		data += SHA256_BLOCK_LENGTH;
+	}
+}
+
+void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH])
+{
+	__u32 state[8] = { 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
+			   0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 };
+	const __be64 bitcount = cpu_to_be64((__u64)len * 8);
+	__u8 final_data[2 * SHA256_BLOCK_LENGTH] = { 0 };
+	size_t final_len = len % SHA256_BLOCK_LENGTH;
+	int i;
+
+	sha256_blocks(state, data, len / SHA256_BLOCK_LENGTH);
+
+	memcpy(final_data, data + len - final_len, final_len);
+	final_data[final_len] = 0x80;
+	final_len = roundup(final_len + 9, SHA256_BLOCK_LENGTH);
+	memcpy(&final_data[final_len - 8], &bitcount, 8);
+
+	sha256_blocks(state, final_data, final_len / SHA256_BLOCK_LENGTH);
+
+	for (i = 0; i < ARRAY_SIZE(state); i++)
+		put_unaligned_be32(state[i], &out[4 * i]);
+}
diff --git a/tools/lib/bpf/libbpf_version.h b/tools/lib/bpf/libbpf_version.h
new file mode 100644
index 000000000..c446c0cd8
--- /dev/null
+++ b/tools/lib/bpf/libbpf_version.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (C) 2021 Facebook */
+#ifndef __LIBBPF_VERSION_H
+#define __LIBBPF_VERSION_H
+
+#define LIBBPF_MAJOR_VERSION 1
+#define LIBBPF_MINOR_VERSION 8
+
+#endif /* __LIBBPF_VERSION_H */
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
new file mode 100644
index 000000000..78f92c392
--- /dev/null
+++ b/tools/lib/bpf/linker.c
@@ -0,0 +1,3116 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/*
+ * BPF static linker
+ *
+ * Copyright (c) 2021 Facebook
+ */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <linux/err.h>
+#include <linux/btf.h>
+#include <elf.h>
+#include <libelf.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include "libbpf.h"
+#include "btf.h"
+#include "libbpf_internal.h"
+#include "strset.h"
+
+#define BTF_EXTERN_SEC ".extern"
+
+struct src_sec {
+	const char *sec_name;
+	/* positional (not necessarily ELF) index in an array of sections */
+	int id;
+	/* positional (not necessarily ELF) index of a matching section in a final object file */
+	int dst_id;
+	/* section data offset in a matching output section */
+	int dst_off;
+	/* whether section is omitted from the final ELF file */
+	bool skipped;
+	/* whether section is an ephemeral section, not mapped to an ELF section */
+	bool ephemeral;
+
+	/* ELF info */
+	size_t sec_idx;
+	Elf_Scn *scn;
+	Elf64_Shdr *shdr;
+	Elf_Data *data;
+
+	/* corresponding BTF DATASEC type ID */
+	int sec_type_id;
+};
+
+struct src_obj {
+	const char *filename;
+	int fd;
+	Elf *elf;
+	/* Section header strings section index */
+	size_t shstrs_sec_idx;
+	/* SYMTAB section index */
+	size_t symtab_sec_idx;
+
+	struct btf *btf;
+	struct btf_ext *btf_ext;
+
+	/* List of sections (including ephemeral). Slot zero is unused. */
+	struct src_sec *secs;
+	int sec_cnt;
+
+	/* mapping of symbol indices from src to dst ELF */
+	int *sym_map;
+	/* mapping from the src BTF type IDs to dst ones */
+	int *btf_type_map;
+};
+
+/* single .BTF.ext data section */
+struct btf_ext_sec_data {
+	size_t rec_cnt;
+	__u32 rec_sz;
+	void *recs;
+};
+
+struct glob_sym {
+	/* ELF symbol index */
+	int sym_idx;
+	/* associated section id for .ksyms, .kconfig, etc, but not .extern */
+	int sec_id;
+	/* extern name offset in STRTAB */
+	int name_off;
+	/* optional associated BTF type ID */
+	int btf_id;
+	/* BTF type ID to which VAR/FUNC type is pointing to; used for
+	 * rewriting types when extern VAR/FUNC is resolved to a concrete
+	 * definition
+	 */
+	int underlying_btf_id;
+	/* sec_var index in the corresponding dst_sec, if exists */
+	int var_idx;
+
+	/* extern or resolved/global symbol */
+	bool is_extern;
+	/* weak or strong symbol, never goes back from strong to weak */
+	bool is_weak;
+};
+
+struct dst_sec {
+	char *sec_name;
+	/* positional (not necessarily ELF) index in an array of sections */
+	int id;
+
+	bool ephemeral;
+
+	/* ELF info */
+	size_t sec_idx;
+	Elf_Scn *scn;
+	Elf64_Shdr *shdr;
+	Elf_Data *data;
+
+	/* final output section size */
+	int sec_sz;
+	/* final output contents of the section */
+	void *raw_data;
+
+	/* corresponding STT_SECTION symbol index in SYMTAB */
+	int sec_sym_idx;
+
+	/* section's DATASEC variable info, emitted on BTF finalization */
+	bool has_btf;
+	int sec_var_cnt;
+	struct btf_var_secinfo *sec_vars;
+
+	/* section's .BTF.ext data */
+	struct btf_ext_sec_data func_info;
+	struct btf_ext_sec_data line_info;
+	struct btf_ext_sec_data core_relo_info;
+};
+
+struct bpf_linker {
+	char *filename;
+	int fd;
+	Elf *elf;
+	Elf64_Ehdr *elf_hdr;
+	bool swapped_endian;
+
+	/* Output sections metadata */
+	struct dst_sec *secs;
+	int sec_cnt;
+
+	struct strset *strtab_strs; /* STRTAB unique strings */
+	size_t strtab_sec_idx; /* STRTAB section index */
+	size_t symtab_sec_idx; /* SYMTAB section index */
+
+	struct btf *btf;
+	struct btf_ext *btf_ext;
+
+	/* global (including extern) ELF symbols */
+	int glob_sym_cnt;
+	struct glob_sym *glob_syms;
+
+	bool fd_is_owned;
+};
+
+#define pr_warn_elf(fmt, ...)									\
+	libbpf_print(LIBBPF_WARN, "libbpf: " fmt ": %s\n", ##__VA_ARGS__, elf_errmsg(-1))
+
+static int init_output_elf(struct bpf_linker *linker);
+
+static int bpf_linker_add_file(struct bpf_linker *linker, int fd,
+			       const char *filename);
+
+static int linker_load_obj_file(struct bpf_linker *linker,
+				struct src_obj *obj);
+static int linker_sanity_check_elf(struct src_obj *obj);
+static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec);
+static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec);
+static int linker_sanity_check_btf(struct src_obj *obj);
+static int linker_sanity_check_btf_ext(struct src_obj *obj);
+static int linker_fixup_btf(struct src_obj *obj);
+static int linker_append_sec_data(struct bpf_linker *linker, struct src_obj *obj);
+static int linker_append_elf_syms(struct bpf_linker *linker, struct src_obj *obj);
+static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj,
+				 Elf64_Sym *sym, const char *sym_name, int src_sym_idx);
+static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *obj);
+static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj);
+static int linker_append_btf_ext(struct bpf_linker *linker, struct src_obj *obj);
+
+static int finalize_btf(struct bpf_linker *linker);
+static int finalize_btf_ext(struct bpf_linker *linker);
+
+void bpf_linker__free(struct bpf_linker *linker)
+{
+	int i;
+
+	if (!linker)
+		return;
+
+	free(linker->filename);
+
+	if (linker->elf)
+		elf_end(linker->elf);
+
+	if (linker->fd >= 0 && linker->fd_is_owned)
+		close(linker->fd);
+
+	strset__free(linker->strtab_strs);
+
+	btf__free(linker->btf);
+	btf_ext__free(linker->btf_ext);
+
+	for (i = 1; i < linker->sec_cnt; i++) {
+		struct dst_sec *sec = &linker->secs[i];
+
+		free(sec->sec_name);
+		free(sec->raw_data);
+		free(sec->sec_vars);
+
+		free(sec->func_info.recs);
+		free(sec->line_info.recs);
+		free(sec->core_relo_info.recs);
+	}
+	free(linker->secs);
+
+	free(linker->glob_syms);
+	free(linker);
+}
+
+struct bpf_linker *bpf_linker__new(const char *filename, struct bpf_linker_opts *opts)
+{
+	struct bpf_linker *linker;
+	int err;
+
+	if (!OPTS_VALID(opts, bpf_linker_opts))
+		return errno = EINVAL, NULL;
+
+	if (elf_version(EV_CURRENT) == EV_NONE) {
+		pr_warn_elf("libelf initialization failed");
+		return errno = EINVAL, NULL;
+	}
+
+	linker = calloc(1, sizeof(*linker));
+	if (!linker)
+		return errno = ENOMEM, NULL;
+
+	linker->filename = strdup(filename);
+	if (!linker->filename) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	linker->fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0644);
+	if (linker->fd < 0) {
+		err = -errno;
+		pr_warn("failed to create '%s': %d\n", filename, err);
+		goto err_out;
+	}
+	linker->fd_is_owned = true;
+
+	err = init_output_elf(linker);
+	if (err)
+		goto err_out;
+
+	return linker;
+
+err_out:
+	bpf_linker__free(linker);
+	return errno = -err, NULL;
+}
+
+struct bpf_linker *bpf_linker__new_fd(int fd, struct bpf_linker_opts *opts)
+{
+	struct bpf_linker *linker;
+	char filename[32];
+	int err;
+
+	if (fd < 0)
+		return errno = EINVAL, NULL;
+
+	if (!OPTS_VALID(opts, bpf_linker_opts))
+		return errno = EINVAL, NULL;
+
+	if (elf_version(EV_CURRENT) == EV_NONE) {
+		pr_warn_elf("libelf initialization failed");
+		return errno = EINVAL, NULL;
+	}
+
+	linker = calloc(1, sizeof(*linker));
+	if (!linker)
+		return errno = ENOMEM, NULL;
+
+	snprintf(filename, sizeof(filename), "fd:%d", fd);
+	linker->filename = strdup(filename);
+	if (!linker->filename) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	linker->fd = fd;
+	linker->fd_is_owned = false;
+
+	err = init_output_elf(linker);
+	if (err)
+		goto err_out;
+
+	return linker;
+
+err_out:
+	bpf_linker__free(linker);
+	return errno = -err, NULL;
+}
+
+static struct dst_sec *add_dst_sec(struct bpf_linker *linker, const char *sec_name)
+{
+	struct dst_sec *secs = linker->secs, *sec;
+	size_t new_cnt = linker->sec_cnt ? linker->sec_cnt + 1 : 2;
+
+	secs = libbpf_reallocarray(secs, new_cnt, sizeof(*secs));
+	if (!secs)
+		return NULL;
+
+	/* zero out newly allocated memory */
+	memset(secs + linker->sec_cnt, 0, (new_cnt - linker->sec_cnt) * sizeof(*secs));
+
+	linker->secs = secs;
+	linker->sec_cnt = new_cnt;
+
+	sec = &linker->secs[new_cnt - 1];
+	sec->id = new_cnt - 1;
+	sec->sec_name = strdup(sec_name);
+	if (!sec->sec_name)
+		return NULL;
+
+	return sec;
+}
+
+static Elf64_Sym *add_new_sym(struct bpf_linker *linker, size_t *sym_idx)
+{
+	struct dst_sec *symtab = &linker->secs[linker->symtab_sec_idx];
+	Elf64_Sym *syms, *sym;
+	size_t sym_cnt = symtab->sec_sz / sizeof(*sym);
+
+	syms = libbpf_reallocarray(symtab->raw_data, sym_cnt + 1, sizeof(*sym));
+	if (!syms)
+		return NULL;
+
+	sym = &syms[sym_cnt];
+	memset(sym, 0, sizeof(*sym));
+
+	symtab->raw_data = syms;
+	symtab->sec_sz += sizeof(*sym);
+	symtab->shdr->sh_size += sizeof(*sym);
+	symtab->data->d_size += sizeof(*sym);
+
+	if (sym_idx)
+		*sym_idx = sym_cnt;
+
+	return sym;
+}
+
+static int init_output_elf(struct bpf_linker *linker)
+{
+	int err, str_off;
+	Elf64_Sym *init_sym;
+	struct dst_sec *sec;
+
+	linker->elf = elf_begin(linker->fd, ELF_C_WRITE, NULL);
+	if (!linker->elf) {
+		pr_warn_elf("failed to create ELF object");
+		return -EINVAL;
+	}
+
+	/* ELF header */
+	linker->elf_hdr = elf64_newehdr(linker->elf);
+	if (!linker->elf_hdr) {
+		pr_warn_elf("failed to create ELF header");
+		return -EINVAL;
+	}
+
+	linker->elf_hdr->e_machine = EM_BPF;
+	linker->elf_hdr->e_type = ET_REL;
+	/* Set unknown ELF endianness, assign later from input files */
+	linker->elf_hdr->e_ident[EI_DATA] = ELFDATANONE;
+
+	/* STRTAB */
+	/* initialize strset with an empty string to conform to ELF */
+	linker->strtab_strs = strset__new(INT_MAX, "", sizeof(""));
+	if (libbpf_get_error(linker->strtab_strs))
+		return libbpf_get_error(linker->strtab_strs);
+
+	sec = add_dst_sec(linker, ".strtab");
+	if (!sec)
+		return -ENOMEM;
+
+	sec->scn = elf_newscn(linker->elf);
+	if (!sec->scn) {
+		pr_warn_elf("failed to create STRTAB section");
+		return -EINVAL;
+	}
+
+	sec->shdr = elf64_getshdr(sec->scn);
+	if (!sec->shdr)
+		return -EINVAL;
+
+	sec->data = elf_newdata(sec->scn);
+	if (!sec->data) {
+		pr_warn_elf("failed to create STRTAB data");
+		return -EINVAL;
+	}
+
+	str_off = strset__add_str(linker->strtab_strs, sec->sec_name);
+	if (str_off < 0)
+		return str_off;
+
+	sec->sec_idx = elf_ndxscn(sec->scn);
+	linker->elf_hdr->e_shstrndx = sec->sec_idx;
+	linker->strtab_sec_idx = sec->sec_idx;
+
+	sec->shdr->sh_name = str_off;
+	sec->shdr->sh_type = SHT_STRTAB;
+	sec->shdr->sh_flags = SHF_STRINGS;
+	sec->shdr->sh_offset = 0;
+	sec->shdr->sh_link = 0;
+	sec->shdr->sh_info = 0;
+	sec->shdr->sh_addralign = 1;
+	sec->shdr->sh_size = sec->sec_sz = 0;
+	sec->shdr->sh_entsize = 0;
+
+	/* SYMTAB */
+	sec = add_dst_sec(linker, ".symtab");
+	if (!sec)
+		return -ENOMEM;
+
+	sec->scn = elf_newscn(linker->elf);
+	if (!sec->scn) {
+		pr_warn_elf("failed to create SYMTAB section");
+		return -EINVAL;
+	}
+
+	sec->shdr = elf64_getshdr(sec->scn);
+	if (!sec->shdr)
+		return -EINVAL;
+
+	sec->data = elf_newdata(sec->scn);
+	if (!sec->data) {
+		pr_warn_elf("failed to create SYMTAB data");
+		return -EINVAL;
+	}
+	/* Ensure libelf translates byte-order of symbol records */
+	sec->data->d_type = ELF_T_SYM;
+
+	str_off = strset__add_str(linker->strtab_strs, sec->sec_name);
+	if (str_off < 0)
+		return str_off;
+
+	sec->sec_idx = elf_ndxscn(sec->scn);
+	linker->symtab_sec_idx = sec->sec_idx;
+
+	sec->shdr->sh_name = str_off;
+	sec->shdr->sh_type = SHT_SYMTAB;
+	sec->shdr->sh_flags = 0;
+	sec->shdr->sh_offset = 0;
+	sec->shdr->sh_link = linker->strtab_sec_idx;
+	/* sh_info should be one greater than the index of the last local
+	 * symbol (i.e., binding is STB_LOCAL). But why and who cares?
+	 */
+	sec->shdr->sh_info = 0;
+	sec->shdr->sh_addralign = 8;
+	sec->shdr->sh_entsize = sizeof(Elf64_Sym);
+
+	/* .BTF */
+	linker->btf = btf__new_empty();
+	err = libbpf_get_error(linker->btf);
+	if (err)
+		return err;
+
+	/* add the special all-zero symbol */
+	init_sym = add_new_sym(linker, NULL);
+	if (!init_sym)
+		return -EINVAL;
+
+	init_sym->st_name = 0;
+	init_sym->st_info = 0;
+	init_sym->st_other = 0;
+	init_sym->st_shndx = SHN_UNDEF;
+	init_sym->st_value = 0;
+	init_sym->st_size = 0;
+
+	return 0;
+}
+
+static int bpf_linker_add_file(struct bpf_linker *linker, int fd,
+			       const char *filename)
+{
+	struct src_obj obj = {};
+	int err = 0;
+
+	obj.filename = filename;
+	obj.fd = fd;
+
+	err = err ?: linker_load_obj_file(linker, &obj);
+	err = err ?: linker_append_sec_data(linker, &obj);
+	err = err ?: linker_append_elf_syms(linker, &obj);
+	err = err ?: linker_append_elf_relos(linker, &obj);
+	err = err ?: linker_append_btf(linker, &obj);
+	err = err ?: linker_append_btf_ext(linker, &obj);
+
+	/* free up src_obj resources */
+	free(obj.btf_type_map);
+	btf__free(obj.btf);
+	btf_ext__free(obj.btf_ext);
+	free(obj.secs);
+	free(obj.sym_map);
+	if (obj.elf)
+		elf_end(obj.elf);
+
+	return err;
+}
+
+int bpf_linker__add_file(struct bpf_linker *linker, const char *filename,
+			 const struct bpf_linker_file_opts *opts)
+{
+	int fd, err;
+
+	if (!OPTS_VALID(opts, bpf_linker_file_opts))
+		return libbpf_err(-EINVAL);
+
+	if (!linker->elf)
+		return libbpf_err(-EINVAL);
+
+	fd = open(filename, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		err = -errno;
+		pr_warn("failed to open file '%s': %s\n", filename, errstr(err));
+		return libbpf_err(err);
+	}
+
+	err = bpf_linker_add_file(linker, fd, filename);
+	close(fd);
+	return libbpf_err(err);
+}
+
+int bpf_linker__add_fd(struct bpf_linker *linker, int fd,
+		       const struct bpf_linker_file_opts *opts)
+{
+	char filename[32];
+	int err;
+
+	if (!OPTS_VALID(opts, bpf_linker_file_opts))
+		return libbpf_err(-EINVAL);
+
+	if (!linker->elf)
+		return libbpf_err(-EINVAL);
+
+	if (fd < 0)
+		return libbpf_err(-EINVAL);
+
+	snprintf(filename, sizeof(filename), "fd:%d", fd);
+	err = bpf_linker_add_file(linker, fd, filename);
+	return libbpf_err(err);
+}
+
+int bpf_linker__add_buf(struct bpf_linker *linker, void *buf, size_t buf_sz,
+			const struct bpf_linker_file_opts *opts)
+{
+	char filename[32];
+	int fd, written, ret;
+
+	if (!OPTS_VALID(opts, bpf_linker_file_opts))
+		return libbpf_err(-EINVAL);
+
+	if (!linker->elf)
+		return libbpf_err(-EINVAL);
+
+	snprintf(filename, sizeof(filename), "mem:%p+%zu", buf, buf_sz);
+
+	fd = sys_memfd_create(filename, 0);
+	if (fd < 0) {
+		ret = -errno;
+		pr_warn("failed to create memfd '%s': %s\n", filename, errstr(ret));
+		return libbpf_err(ret);
+	}
+
+	written = 0;
+	while (written < buf_sz) {
+		ret = write(fd, buf + written, buf_sz - written);
+		if (ret < 0) {
+			ret = -errno;
+			pr_warn("failed to write '%s': %s\n", filename, errstr(ret));
+			goto err_out;
+		}
+		written += ret;
+	}
+
+	ret = bpf_linker_add_file(linker, fd, filename);
+err_out:
+	close(fd);
+	return libbpf_err(ret);
+}
+
+static bool is_dwarf_sec_name(const char *name)
+{
+	/* approximation, but the actual list is too long */
+	return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0;
+}
+
+static bool is_ignored_sec(struct src_sec *sec)
+{
+	Elf64_Shdr *shdr = sec->shdr;
+	const char *name = sec->sec_name;
+
+	/* no special handling of .strtab */
+	if (shdr->sh_type == SHT_STRTAB)
+		return true;
+
+	/* ignore .llvm_addrsig section as well */
+	if (shdr->sh_type == SHT_LLVM_ADDRSIG)
+		return true;
+
+	/* no subprograms will lead to an empty .text section, ignore it */
+	if (shdr->sh_type == SHT_PROGBITS && shdr->sh_size == 0 &&
+	    strcmp(sec->sec_name, ".text") == 0)
+		return true;
+
+	/* DWARF sections */
+	if (is_dwarf_sec_name(sec->sec_name))
+		return true;
+
+	if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) {
+		name += sizeof(".rel") - 1;
+		/* DWARF section relocations */
+		if (is_dwarf_sec_name(name))
+			return true;
+
+		/* .BTF and .BTF.ext don't need relocations */
+		if (strcmp(name, BTF_ELF_SEC) == 0 ||
+		    strcmp(name, BTF_EXT_ELF_SEC) == 0)
+			return true;
+	}
+
+	return false;
+}
+
+static struct src_sec *add_src_sec(struct src_obj *obj, const char *sec_name)
+{
+	struct src_sec *secs = obj->secs, *sec;
+	size_t new_cnt = obj->sec_cnt ? obj->sec_cnt + 1 : 2;
+
+	secs = libbpf_reallocarray(secs, new_cnt, sizeof(*secs));
+	if (!secs)
+		return NULL;
+
+	/* zero out newly allocated memory */
+	memset(secs + obj->sec_cnt, 0, (new_cnt - obj->sec_cnt) * sizeof(*secs));
+
+	obj->secs = secs;
+	obj->sec_cnt = new_cnt;
+
+	sec = &obj->secs[new_cnt - 1];
+	sec->id = new_cnt - 1;
+	sec->sec_name = sec_name;
+
+	return sec;
+}
+
+static int linker_load_obj_file(struct bpf_linker *linker,
+				struct src_obj *obj)
+{
+	int err = 0;
+	Elf_Scn *scn;
+	Elf_Data *data;
+	Elf64_Ehdr *ehdr;
+	Elf64_Shdr *shdr;
+	struct src_sec *sec;
+	unsigned char obj_byteorder;
+	unsigned char link_byteorder = linker->elf_hdr->e_ident[EI_DATA];
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	const unsigned char host_byteorder = ELFDATA2LSB;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	const unsigned char host_byteorder = ELFDATA2MSB;
+#else
+#error "Unknown __BYTE_ORDER__"
+#endif
+
+	pr_debug("linker: adding object file '%s'...\n", obj->filename);
+
+	obj->elf = elf_begin(obj->fd, ELF_C_READ_MMAP, NULL);
+	if (!obj->elf) {
+		pr_warn_elf("failed to parse ELF file '%s'", obj->filename);
+		return -EINVAL;
+	}
+
+	/* Sanity check ELF file high-level properties */
+	ehdr = elf64_getehdr(obj->elf);
+	if (!ehdr) {
+		pr_warn_elf("failed to get ELF header for %s", obj->filename);
+		return -EINVAL;
+	}
+
+	/* Linker output endianness set by first input object */
+	obj_byteorder = ehdr->e_ident[EI_DATA];
+	if (obj_byteorder != ELFDATA2LSB && obj_byteorder != ELFDATA2MSB) {
+		err = -EOPNOTSUPP;
+		pr_warn("unknown byte order of ELF file %s\n", obj->filename);
+		return err;
+	}
+	if (link_byteorder == ELFDATANONE) {
+		linker->elf_hdr->e_ident[EI_DATA] = obj_byteorder;
+		linker->swapped_endian = obj_byteorder != host_byteorder;
+		pr_debug("linker: set %s-endian output byte order\n",
+			 obj_byteorder == ELFDATA2MSB ? "big" : "little");
+	} else if (link_byteorder != obj_byteorder) {
+		err = -EOPNOTSUPP;
+		pr_warn("byte order mismatch with ELF file %s\n", obj->filename);
+		return err;
+	}
+
+	if (ehdr->e_type != ET_REL
+	    || ehdr->e_machine != EM_BPF
+	    || ehdr->e_ident[EI_CLASS] != ELFCLASS64) {
+		err = -EOPNOTSUPP;
+		pr_warn_elf("unsupported kind of ELF file %s", obj->filename);
+		return err;
+	}
+
+	if (elf_getshdrstrndx(obj->elf, &obj->shstrs_sec_idx)) {
+		pr_warn_elf("failed to get SHSTRTAB section index for %s", obj->filename);
+		return -EINVAL;
+	}
+
+	scn = NULL;
+	while ((scn = elf_nextscn(obj->elf, scn)) != NULL) {
+		size_t sec_idx = elf_ndxscn(scn);
+		const char *sec_name;
+
+		shdr = elf64_getshdr(scn);
+		if (!shdr) {
+			pr_warn_elf("failed to get section #%zu header for %s",
+				    sec_idx, obj->filename);
+			return -EINVAL;
+		}
+
+		sec_name = elf_strptr(obj->elf, obj->shstrs_sec_idx, shdr->sh_name);
+		if (!sec_name) {
+			pr_warn_elf("failed to get section #%zu name for %s",
+				    sec_idx, obj->filename);
+			return -EINVAL;
+		}
+
+		data = elf_getdata(scn, 0);
+		if (!data) {
+			pr_warn_elf("failed to get section #%zu (%s) data from %s",
+				    sec_idx, sec_name, obj->filename);
+			return -EINVAL;
+		}
+
+		sec = add_src_sec(obj, sec_name);
+		if (!sec)
+			return -ENOMEM;
+
+		sec->scn = scn;
+		sec->shdr = shdr;
+		sec->data = data;
+		sec->sec_idx = elf_ndxscn(scn);
+
+		if (is_ignored_sec(sec)) {
+			sec->skipped = true;
+			continue;
+		}
+
+		switch (shdr->sh_type) {
+		case SHT_SYMTAB:
+			if (obj->symtab_sec_idx) {
+				err = -EOPNOTSUPP;
+				pr_warn("multiple SYMTAB sections found, not supported\n");
+				return err;
+			}
+			obj->symtab_sec_idx = sec_idx;
+			break;
+		case SHT_STRTAB:
+			/* we'll construct our own string table */
+			break;
+		case SHT_PROGBITS:
+			if (strcmp(sec_name, BTF_ELF_SEC) == 0) {
+				obj->btf = btf__new(data->d_buf, shdr->sh_size);
+				err = libbpf_get_error(obj->btf);
+				if (err) {
+					pr_warn("failed to parse .BTF from %s: %s\n",
+						obj->filename, errstr(err));
+					return err;
+				}
+				sec->skipped = true;
+				continue;
+			}
+			if (strcmp(sec_name, BTF_EXT_ELF_SEC) == 0) {
+				obj->btf_ext = btf_ext__new(data->d_buf, shdr->sh_size);
+				err = libbpf_get_error(obj->btf_ext);
+				if (err) {
+					pr_warn("failed to parse .BTF.ext from '%s': %s\n",
+						obj->filename, errstr(err));
+					return err;
+				}
+				sec->skipped = true;
+				continue;
+			}
+
+			/* data & code */
+			break;
+		case SHT_NOBITS:
+			/* BSS */
+			break;
+		case SHT_REL:
+			/* relocations */
+			break;
+		default:
+			pr_warn("unrecognized section #%zu (%s) in %s\n",
+				sec_idx, sec_name, obj->filename);
+			err = -EINVAL;
+			return err;
+		}
+	}
+
+	err = err ?: linker_sanity_check_elf(obj);
+	err = err ?: linker_sanity_check_btf(obj);
+	err = err ?: linker_sanity_check_btf_ext(obj);
+	err = err ?: linker_fixup_btf(obj);
+
+	return err;
+}
+
+static int linker_sanity_check_elf(struct src_obj *obj)
+{
+	struct src_sec *sec;
+	int i, err;
+
+	if (!obj->symtab_sec_idx) {
+		pr_warn("ELF is missing SYMTAB section in %s\n", obj->filename);
+		return -EINVAL;
+	}
+	if (!obj->shstrs_sec_idx) {
+		pr_warn("ELF is missing section headers STRTAB section in %s\n", obj->filename);
+		return -EINVAL;
+	}
+
+	for (i = 1; i < obj->sec_cnt; i++) {
+		sec = &obj->secs[i];
+
+		if (sec->sec_name[0] == '\0') {
+			pr_warn("ELF section #%zu has empty name in %s\n", sec->sec_idx, obj->filename);
+			return -EINVAL;
+		}
+
+		if (is_dwarf_sec_name(sec->sec_name))
+			continue;
+
+		if (sec->shdr->sh_addralign && !is_pow_of_2(sec->shdr->sh_addralign)) {
+			pr_warn("ELF section #%zu alignment %llu is non pow-of-2 alignment in %s\n",
+				sec->sec_idx, (long long unsigned)sec->shdr->sh_addralign,
+				obj->filename);
+			return -EINVAL;
+		}
+		if (sec->shdr->sh_addralign != sec->data->d_align) {
+			pr_warn("ELF section #%zu has inconsistent alignment addr=%llu != d=%llu in %s\n",
+				sec->sec_idx, (long long unsigned)sec->shdr->sh_addralign,
+				(long long unsigned)sec->data->d_align, obj->filename);
+			return -EINVAL;
+		}
+
+		if (sec->shdr->sh_size != sec->data->d_size) {
+			pr_warn("ELF section #%zu has inconsistent section size sh=%llu != d=%llu in %s\n",
+				sec->sec_idx, (long long unsigned)sec->shdr->sh_size,
+				(long long unsigned)sec->data->d_size, obj->filename);
+			return -EINVAL;
+		}
+
+		switch (sec->shdr->sh_type) {
+		case SHT_SYMTAB:
+			err = linker_sanity_check_elf_symtab(obj, sec);
+			if (err)
+				return err;
+			break;
+		case SHT_STRTAB:
+			break;
+		case SHT_PROGBITS:
+			if (sec->shdr->sh_flags & SHF_EXECINSTR) {
+				if (sec->shdr->sh_size % sizeof(struct bpf_insn) != 0) {
+					pr_warn("ELF section #%zu has unexpected size alignment %llu in %s\n",
+						sec->sec_idx, (long long unsigned)sec->shdr->sh_size,
+						obj->filename);
+					return -EINVAL;
+				}
+			}
+			break;
+		case SHT_NOBITS:
+			break;
+		case SHT_REL:
+			err = linker_sanity_check_elf_relos(obj, sec);
+			if (err)
+				return err;
+			break;
+		case SHT_LLVM_ADDRSIG:
+			break;
+		default:
+			pr_warn("ELF section #%zu (%s) has unrecognized type %zu in %s\n",
+				sec->sec_idx, sec->sec_name, (size_t)sec->shdr->sh_type, obj->filename);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec)
+{
+	struct src_sec *link_sec;
+	Elf64_Sym *sym;
+	int i, n;
+
+	if (sec->shdr->sh_entsize != sizeof(Elf64_Sym))
+		return -EINVAL;
+	if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0)
+		return -EINVAL;
+
+	if (!sec->shdr->sh_link || sec->shdr->sh_link >= obj->sec_cnt) {
+		pr_warn("ELF SYMTAB section #%zu points to missing STRTAB section #%zu in %s\n",
+			sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
+		return -EINVAL;
+	}
+	link_sec = &obj->secs[sec->shdr->sh_link];
+	if (link_sec->shdr->sh_type != SHT_STRTAB) {
+		pr_warn("ELF SYMTAB section #%zu points to invalid STRTAB section #%zu in %s\n",
+			sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
+		return -EINVAL;
+	}
+
+	n = sec->shdr->sh_size / sec->shdr->sh_entsize;
+	sym = sec->data->d_buf;
+	for (i = 0; i < n; i++, sym++) {
+		int sym_type = ELF64_ST_TYPE(sym->st_info);
+		int sym_bind = ELF64_ST_BIND(sym->st_info);
+		int sym_vis = ELF64_ST_VISIBILITY(sym->st_other);
+
+		if (i == 0) {
+			if (sym->st_name != 0 || sym->st_info != 0
+			    || sym->st_other != 0 || sym->st_shndx != 0
+			    || sym->st_value != 0 || sym->st_size != 0) {
+				pr_warn("ELF sym #0 is invalid in %s\n", obj->filename);
+				return -EINVAL;
+			}
+			continue;
+		}
+		if (sym_bind != STB_LOCAL && sym_bind != STB_GLOBAL && sym_bind != STB_WEAK) {
+			pr_warn("ELF sym #%d in section #%zu has unsupported symbol binding %d\n",
+				i, sec->sec_idx, sym_bind);
+			return -EINVAL;
+		}
+		if (sym_vis != STV_DEFAULT && sym_vis != STV_HIDDEN) {
+			pr_warn("ELF sym #%d in section #%zu has unsupported symbol visibility %d\n",
+				i, sec->sec_idx, sym_vis);
+			return -EINVAL;
+		}
+		if (sym->st_shndx == 0) {
+			if (sym_type != STT_NOTYPE || sym_bind == STB_LOCAL
+			    || sym->st_value != 0 || sym->st_size != 0) {
+				pr_warn("ELF sym #%d is invalid extern symbol in %s\n",
+					i, obj->filename);
+
+				return -EINVAL;
+			}
+			continue;
+		}
+		if (sym->st_shndx < SHN_LORESERVE && sym->st_shndx >= obj->sec_cnt) {
+			pr_warn("ELF sym #%d in section #%zu points to missing section #%zu in %s\n",
+				i, sec->sec_idx, (size_t)sym->st_shndx, obj->filename);
+			return -EINVAL;
+		}
+		if (sym_type == STT_SECTION) {
+			if (sym->st_value != 0)
+				return -EINVAL;
+			continue;
+		}
+	}
+
+	return 0;
+}
+
+static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec)
+{
+	struct src_sec *link_sec, *sym_sec;
+	Elf64_Rel *relo;
+	int i, n;
+
+	if (sec->shdr->sh_entsize != sizeof(Elf64_Rel))
+		return -EINVAL;
+	if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0)
+		return -EINVAL;
+
+	/* SHT_REL's sh_link should point to SYMTAB */
+	if (sec->shdr->sh_link != obj->symtab_sec_idx) {
+		pr_warn("ELF relo section #%zu points to invalid SYMTAB section #%zu in %s\n",
+			sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename);
+		return -EINVAL;
+	}
+
+	/* SHT_REL's sh_info points to relocated section */
+	if (!sec->shdr->sh_info || sec->shdr->sh_info >= obj->sec_cnt) {
+		pr_warn("ELF relo section #%zu points to missing section #%zu in %s\n",
+			sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename);
+		return -EINVAL;
+	}
+	link_sec = &obj->secs[sec->shdr->sh_info];
+
+	/* .rel<secname> -> <secname> pattern is followed */
+	if (strncmp(sec->sec_name, ".rel", sizeof(".rel") - 1) != 0
+	    || strcmp(sec->sec_name + sizeof(".rel") - 1, link_sec->sec_name) != 0) {
+		pr_warn("ELF relo section #%zu name has invalid name in %s\n",
+			sec->sec_idx, obj->filename);
+		return -EINVAL;
+	}
+
+	/* don't further validate relocations for ignored sections */
+	if (link_sec->skipped)
+		return 0;
+
+	/* relocatable section is data or instructions */
+	if (link_sec->shdr->sh_type != SHT_PROGBITS && link_sec->shdr->sh_type != SHT_NOBITS) {
+		pr_warn("ELF relo section #%zu points to invalid section #%zu in %s\n",
+			sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename);
+		return -EINVAL;
+	}
+
+	/* check sanity of each relocation */
+	n = sec->shdr->sh_size / sec->shdr->sh_entsize;
+	relo = sec->data->d_buf;
+	sym_sec = &obj->secs[obj->symtab_sec_idx];
+	for (i = 0; i < n; i++, relo++) {
+		size_t sym_idx = ELF64_R_SYM(relo->r_info);
+		size_t sym_type = ELF64_R_TYPE(relo->r_info);
+
+		if (sym_type != R_BPF_64_64 && sym_type != R_BPF_64_32 &&
+		    sym_type != R_BPF_64_ABS64 && sym_type != R_BPF_64_ABS32) {
+			pr_warn("ELF relo #%d in section #%zu has unexpected type %zu in %s\n",
+				i, sec->sec_idx, sym_type, obj->filename);
+			return -EINVAL;
+		}
+
+		if (!sym_idx || sym_idx * sizeof(Elf64_Sym) >= sym_sec->shdr->sh_size) {
+			pr_warn("ELF relo #%d in section #%zu points to invalid symbol #%zu in %s\n",
+				i, sec->sec_idx, sym_idx, obj->filename);
+			return -EINVAL;
+		}
+
+		if (link_sec->shdr->sh_flags & SHF_EXECINSTR) {
+			if (relo->r_offset % sizeof(struct bpf_insn) != 0) {
+				pr_warn("ELF relo #%d in section #%zu points to missing symbol #%zu in %s\n",
+					i, sec->sec_idx, sym_idx, obj->filename);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int check_btf_type_id(__u32 *type_id, void *ctx)
+{
+	struct btf *btf = ctx;
+
+	if (*type_id >= btf__type_cnt(btf))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int check_btf_str_off(__u32 *str_off, void *ctx)
+{
+	struct btf *btf = ctx;
+	const char *s;
+
+	s = btf__str_by_offset(btf, *str_off);
+
+	if (!s)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int linker_sanity_check_btf(struct src_obj *obj)
+{
+	struct btf_type *t;
+	int i, n, err;
+
+	if (!obj->btf)
+		return 0;
+
+	n = btf__type_cnt(obj->btf);
+	for (i = 1; i < n; i++) {
+		struct btf_field_iter it;
+		__u32 *type_id, *str_off;
+
+		t = btf_type_by_id(obj->btf, i);
+
+		err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS);
+		if (err)
+			return err;
+		while ((type_id = btf_field_iter_next(&it))) {
+			if (*type_id >= n)
+				return -EINVAL;
+		}
+
+		err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS);
+		if (err)
+			return err;
+		while ((str_off = btf_field_iter_next(&it))) {
+			if (!btf__str_by_offset(obj->btf, *str_off))
+				return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int linker_sanity_check_btf_ext(struct src_obj *obj)
+{
+	int err = 0;
+
+	if (!obj->btf_ext)
+		return 0;
+
+	/* can't use .BTF.ext without .BTF */
+	if (!obj->btf)
+		return -EINVAL;
+
+	err = err ?: btf_ext_visit_type_ids(obj->btf_ext, check_btf_type_id, obj->btf);
+	err = err ?: btf_ext_visit_str_offs(obj->btf_ext, check_btf_str_off, obj->btf);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int init_sec(struct bpf_linker *linker, struct dst_sec *dst_sec, struct src_sec *src_sec)
+{
+	Elf_Scn *scn;
+	Elf_Data *data;
+	Elf64_Shdr *shdr;
+	int name_off;
+
+	dst_sec->sec_sz = 0;
+	dst_sec->sec_idx = 0;
+	dst_sec->ephemeral = src_sec->ephemeral;
+
+	/* ephemeral sections are just thin section shells lacking most parts */
+	if (src_sec->ephemeral)
+		return 0;
+
+	scn = elf_newscn(linker->elf);
+	if (!scn)
+		return -ENOMEM;
+	data = elf_newdata(scn);
+	if (!data)
+		return -ENOMEM;
+	shdr = elf64_getshdr(scn);
+	if (!shdr)
+		return -ENOMEM;
+
+	dst_sec->scn = scn;
+	dst_sec->shdr = shdr;
+	dst_sec->data = data;
+	dst_sec->sec_idx = elf_ndxscn(scn);
+
+	name_off = strset__add_str(linker->strtab_strs, src_sec->sec_name);
+	if (name_off < 0)
+		return name_off;
+
+	shdr->sh_name = name_off;
+	shdr->sh_type = src_sec->shdr->sh_type;
+	shdr->sh_flags = src_sec->shdr->sh_flags;
+	shdr->sh_size = 0;
+	/* sh_link and sh_info have different meaning for different types of
+	 * sections, so we leave it up to the caller code to fill them in, if
+	 * necessary
+	 */
+	shdr->sh_link = 0;
+	shdr->sh_info = 0;
+	shdr->sh_addralign = src_sec->shdr->sh_addralign;
+	shdr->sh_entsize = src_sec->shdr->sh_entsize;
+
+	data->d_type = src_sec->data->d_type;
+	data->d_size = 0;
+	data->d_buf = NULL;
+	data->d_align = src_sec->data->d_align;
+	data->d_off = 0;
+
+	return 0;
+}
+
+static struct dst_sec *find_dst_sec_by_name(struct bpf_linker *linker, const char *sec_name)
+{
+	struct dst_sec *sec;
+	int i;
+
+	for (i = 1; i < linker->sec_cnt; i++) {
+		sec = &linker->secs[i];
+
+		if (strcmp(sec->sec_name, sec_name) == 0)
+			return sec;
+	}
+
+	return NULL;
+}
+
+static bool secs_match(struct dst_sec *dst, struct src_sec *src)
+{
+	if (dst->ephemeral || src->ephemeral)
+		return true;
+
+	if (dst->shdr->sh_type != src->shdr->sh_type) {
+		pr_warn("sec %s types mismatch\n", dst->sec_name);
+		return false;
+	}
+	if (dst->shdr->sh_flags != src->shdr->sh_flags) {
+		pr_warn("sec %s flags mismatch\n", dst->sec_name);
+		return false;
+	}
+	if (dst->shdr->sh_entsize != src->shdr->sh_entsize) {
+		pr_warn("sec %s entsize mismatch\n", dst->sec_name);
+		return false;
+	}
+
+	return true;
+}
+
+static bool sec_content_is_same(struct dst_sec *dst_sec, struct src_sec *src_sec)
+{
+	if (dst_sec->sec_sz != src_sec->shdr->sh_size)
+		return false;
+	if (memcmp(dst_sec->raw_data, src_sec->data->d_buf, dst_sec->sec_sz) != 0)
+		return false;
+	return true;
+}
+
+static bool is_exec_sec(struct dst_sec *sec)
+{
+	if (!sec || sec->ephemeral)
+		return false;
+	return (sec->shdr->sh_type == SHT_PROGBITS) &&
+	       (sec->shdr->sh_flags & SHF_EXECINSTR);
+}
+
+static void exec_sec_bswap(void *raw_data, int size)
+{
+	const int insn_cnt = size / sizeof(struct bpf_insn);
+	struct bpf_insn *insn = raw_data;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++, insn++)
+		bpf_insn_bswap(insn);
+}
+
+static int extend_sec(struct bpf_linker *linker, struct dst_sec *dst, struct src_sec *src)
+{
+	void *tmp;
+	size_t dst_align, src_align;
+	size_t dst_align_sz, dst_final_sz;
+	int err;
+
+	/* Ephemeral source section doesn't contribute anything to ELF
+	 * section data.
+	 */
+	if (src->ephemeral)
+		return 0;
+
+	/* Some sections (like .maps) can contain both externs (and thus be
+	 * ephemeral) and non-externs (map definitions). So it's possible that
+	 * it has to be "upgraded" from ephemeral to non-ephemeral when the
+	 * first non-ephemeral entity appears. In such case, we add ELF
+	 * section, data, etc.
+	 */
+	if (dst->ephemeral) {
+		err = init_sec(linker, dst, src);
+		if (err)
+			return err;
+	}
+
+	dst_align = dst->shdr->sh_addralign;
+	src_align = src->shdr->sh_addralign;
+	if (dst_align == 0)
+		dst_align = 1;
+	if (dst_align < src_align)
+		dst_align = src_align;
+
+	dst_align_sz = (dst->sec_sz + dst_align - 1) / dst_align * dst_align;
+
+	/* no need to re-align final size */
+	dst_final_sz = dst_align_sz + src->shdr->sh_size;
+
+	if (src->shdr->sh_type != SHT_NOBITS) {
+		tmp = realloc(dst->raw_data, dst_final_sz);
+		/* If dst_align_sz == 0, realloc() behaves in a special way:
+		 * 1. When dst->raw_data is NULL it returns:
+		 *    "either NULL or a pointer suitable to be passed to free()" [1].
+		 * 2. When dst->raw_data is not-NULL it frees dst->raw_data and returns NULL,
+		 *    thus invalidating any "pointer suitable to be passed to free()" obtained
+		 *    at step (1).
+		 *
+		 * The dst_align_sz > 0 check avoids error exit after (2), otherwise
+		 * dst->raw_data would be freed again in bpf_linker__free().
+		 *
+		 * [1] man 3 realloc
+		 */
+		if (!tmp && dst_align_sz > 0)
+			return -ENOMEM;
+		dst->raw_data = tmp;
+
+		/* pad dst section, if it's alignment forced size increase */
+		memset(dst->raw_data + dst->sec_sz, 0, dst_align_sz - dst->sec_sz);
+		/* now copy src data at a properly aligned offset */
+		memcpy(dst->raw_data + dst_align_sz, src->data->d_buf, src->shdr->sh_size);
+
+		/* convert added bpf insns to native byte-order */
+		if (linker->swapped_endian && is_exec_sec(dst))
+			exec_sec_bswap(dst->raw_data + dst_align_sz, src->shdr->sh_size);
+	}
+
+	dst->sec_sz = dst_final_sz;
+	dst->shdr->sh_size = dst_final_sz;
+	dst->data->d_size = dst_final_sz;
+
+	dst->shdr->sh_addralign = dst_align;
+	dst->data->d_align = dst_align;
+
+	src->dst_off = dst_align_sz;
+
+	return 0;
+}
+
+static bool is_data_sec(struct src_sec *sec)
+{
+	if (!sec || sec->skipped)
+		return false;
+	/* ephemeral sections are data sections, e.g., .kconfig, .ksyms */
+	if (sec->ephemeral)
+		return true;
+	return sec->shdr->sh_type == SHT_PROGBITS || sec->shdr->sh_type == SHT_NOBITS;
+}
+
+static bool is_relo_sec(struct src_sec *sec)
+{
+	if (!sec || sec->skipped || sec->ephemeral)
+		return false;
+	return sec->shdr->sh_type == SHT_REL;
+}
+
+static int linker_append_sec_data(struct bpf_linker *linker, struct src_obj *obj)
+{
+	int i, err;
+
+	for (i = 1; i < obj->sec_cnt; i++) {
+		struct src_sec *src_sec;
+		struct dst_sec *dst_sec;
+
+		src_sec = &obj->secs[i];
+		if (!is_data_sec(src_sec))
+			continue;
+
+		dst_sec = find_dst_sec_by_name(linker, src_sec->sec_name);
+		if (!dst_sec) {
+			dst_sec = add_dst_sec(linker, src_sec->sec_name);
+			if (!dst_sec)
+				return -ENOMEM;
+			err = init_sec(linker, dst_sec, src_sec);
+			if (err) {
+				pr_warn("failed to init section '%s'\n", src_sec->sec_name);
+				return err;
+			}
+		} else {
+			if (!secs_match(dst_sec, src_sec)) {
+				pr_warn("ELF sections %s are incompatible\n", src_sec->sec_name);
+				return -EINVAL;
+			}
+
+			/* "license" and "version" sections are deduped */
+			if (strcmp(src_sec->sec_name, "license") == 0
+			    || strcmp(src_sec->sec_name, "version") == 0) {
+				if (!sec_content_is_same(dst_sec, src_sec)) {
+					pr_warn("non-identical contents of section '%s' are not supported\n", src_sec->sec_name);
+					return -EINVAL;
+				}
+				src_sec->skipped = true;
+				src_sec->dst_id = dst_sec->id;
+				continue;
+			}
+		}
+
+		/* record mapped section index */
+		src_sec->dst_id = dst_sec->id;
+
+		err = extend_sec(linker, dst_sec, src_sec);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int linker_append_elf_syms(struct bpf_linker *linker, struct src_obj *obj)
+{
+	struct src_sec *symtab = &obj->secs[obj->symtab_sec_idx];
+	Elf64_Sym *sym = symtab->data->d_buf;
+	int i, n = symtab->shdr->sh_size / symtab->shdr->sh_entsize, err;
+	int str_sec_idx = symtab->shdr->sh_link;
+	const char *sym_name;
+
+	obj->sym_map = calloc(n + 1, sizeof(*obj->sym_map));
+	if (!obj->sym_map)
+		return -ENOMEM;
+
+	for (i = 0; i < n; i++, sym++) {
+		/* We already validated all-zero symbol #0 and we already
+		 * appended it preventively to the final SYMTAB, so skip it.
+		 */
+		if (i == 0)
+			continue;
+
+		sym_name = elf_strptr(obj->elf, str_sec_idx, sym->st_name);
+		if (!sym_name) {
+			pr_warn("can't fetch symbol name for symbol #%d in '%s'\n", i, obj->filename);
+			return -EINVAL;
+		}
+
+		err = linker_append_elf_sym(linker, obj, sym, sym_name, i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static Elf64_Sym *get_sym_by_idx(struct bpf_linker *linker, size_t sym_idx)
+{
+	struct dst_sec *symtab = &linker->secs[linker->symtab_sec_idx];
+	Elf64_Sym *syms = symtab->raw_data;
+
+	return &syms[sym_idx];
+}
+
+static struct glob_sym *find_glob_sym(struct bpf_linker *linker, const char *sym_name)
+{
+	struct glob_sym *glob_sym;
+	const char *name;
+	int i;
+
+	for (i = 0; i < linker->glob_sym_cnt; i++) {
+		glob_sym = &linker->glob_syms[i];
+		name = strset__data(linker->strtab_strs) + glob_sym->name_off;
+
+		if (strcmp(name, sym_name) == 0)
+			return glob_sym;
+	}
+
+	return NULL;
+}
+
+static struct glob_sym *add_glob_sym(struct bpf_linker *linker)
+{
+	struct glob_sym *syms, *sym;
+
+	syms = libbpf_reallocarray(linker->glob_syms, linker->glob_sym_cnt + 1,
+				   sizeof(*linker->glob_syms));
+	if (!syms)
+		return NULL;
+
+	sym = &syms[linker->glob_sym_cnt];
+	memset(sym, 0, sizeof(*sym));
+	sym->var_idx = -1;
+
+	linker->glob_syms = syms;
+	linker->glob_sym_cnt++;
+
+	return sym;
+}
+
+static bool glob_sym_btf_matches(const char *sym_name, bool exact,
+				 const struct btf *btf1, __u32 id1,
+				 const struct btf *btf2, __u32 id2)
+{
+	const struct btf_type *t1, *t2;
+	bool is_static1, is_static2;
+	const char *n1, *n2;
+	int i, n;
+
+recur:
+	n1 = n2 = NULL;
+	t1 = skip_mods_and_typedefs(btf1, id1, &id1);
+	t2 = skip_mods_and_typedefs(btf2, id2, &id2);
+
+	/* check if only one side is FWD, otherwise handle with common logic */
+	if (!exact && btf_is_fwd(t1) != btf_is_fwd(t2)) {
+		n1 = btf__str_by_offset(btf1, t1->name_off);
+		n2 = btf__str_by_offset(btf2, t2->name_off);
+		if (strcmp(n1, n2) != 0) {
+			pr_warn("global '%s': incompatible forward declaration names '%s' and '%s'\n",
+				sym_name, n1, n2);
+			return false;
+		}
+		/* validate if FWD kind matches concrete kind */
+		if (btf_is_fwd(t1)) {
+			if (btf_kflag(t1) && btf_is_union(t2))
+				return true;
+			if (!btf_kflag(t1) && btf_is_struct(t2))
+				return true;
+			pr_warn("global '%s': incompatible %s forward declaration and concrete kind %s\n",
+				sym_name, btf_kflag(t1) ? "union" : "struct", btf_kind_str(t2));
+		} else {
+			if (btf_kflag(t2) && btf_is_union(t1))
+				return true;
+			if (!btf_kflag(t2) && btf_is_struct(t1))
+				return true;
+			pr_warn("global '%s': incompatible %s forward declaration and concrete kind %s\n",
+				sym_name, btf_kflag(t2) ? "union" : "struct", btf_kind_str(t1));
+		}
+		return false;
+	}
+
+	if (btf_kind(t1) != btf_kind(t2)) {
+		pr_warn("global '%s': incompatible BTF kinds %s and %s\n",
+			sym_name, btf_kind_str(t1), btf_kind_str(t2));
+		return false;
+	}
+
+	switch (btf_kind(t1)) {
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+	case BTF_KIND_FWD:
+	case BTF_KIND_FUNC:
+	case BTF_KIND_VAR:
+		n1 = btf__str_by_offset(btf1, t1->name_off);
+		n2 = btf__str_by_offset(btf2, t2->name_off);
+		if (strcmp(n1, n2) != 0) {
+			pr_warn("global '%s': incompatible %s names '%s' and '%s'\n",
+				sym_name, btf_kind_str(t1), n1, n2);
+			return false;
+		}
+		break;
+	default:
+		break;
+	}
+
+	switch (btf_kind(t1)) {
+	case BTF_KIND_UNKN: /* void */
+	case BTF_KIND_FWD:
+		return true;
+	case BTF_KIND_INT:
+	case BTF_KIND_FLOAT:
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		/* ignore encoding for int and enum values for enum */
+		if (t1->size != t2->size) {
+			pr_warn("global '%s': incompatible %s '%s' size %u and %u\n",
+				sym_name, btf_kind_str(t1), n1, t1->size, t2->size);
+			return false;
+		}
+		return true;
+	case BTF_KIND_PTR:
+		/* just validate overall shape of the referenced type, so no
+		 * contents comparison for struct/union, and allowed fwd vs
+		 * struct/union
+		 */
+		exact = false;
+		id1 = t1->type;
+		id2 = t2->type;
+		goto recur;
+	case BTF_KIND_ARRAY:
+		/* ignore index type and array size */
+		id1 = btf_array(t1)->type;
+		id2 = btf_array(t2)->type;
+		goto recur;
+	case BTF_KIND_FUNC:
+		/* extern and global linkages are compatible */
+		is_static1 = btf_func_linkage(t1) == BTF_FUNC_STATIC;
+		is_static2 = btf_func_linkage(t2) == BTF_FUNC_STATIC;
+		if (is_static1 != is_static2) {
+			pr_warn("global '%s': incompatible func '%s' linkage\n", sym_name, n1);
+			return false;
+		}
+
+		id1 = t1->type;
+		id2 = t2->type;
+		goto recur;
+	case BTF_KIND_VAR:
+		/* extern and global linkages are compatible */
+		is_static1 = btf_var(t1)->linkage == BTF_VAR_STATIC;
+		is_static2 = btf_var(t2)->linkage == BTF_VAR_STATIC;
+		if (is_static1 != is_static2) {
+			pr_warn("global '%s': incompatible var '%s' linkage\n", sym_name, n1);
+			return false;
+		}
+
+		id1 = t1->type;
+		id2 = t2->type;
+		goto recur;
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION: {
+		const struct btf_member *m1, *m2;
+
+		if (!exact)
+			return true;
+
+		if (btf_vlen(t1) != btf_vlen(t2)) {
+			pr_warn("global '%s': incompatible number of %s fields %u and %u\n",
+				sym_name, btf_kind_str(t1), btf_vlen(t1), btf_vlen(t2));
+			return false;
+		}
+
+		n = btf_vlen(t1);
+		m1 = btf_members(t1);
+		m2 = btf_members(t2);
+		for (i = 0; i < n; i++, m1++, m2++) {
+			n1 = btf__str_by_offset(btf1, m1->name_off);
+			n2 = btf__str_by_offset(btf2, m2->name_off);
+			if (strcmp(n1, n2) != 0) {
+				pr_warn("global '%s': incompatible field #%d names '%s' and '%s'\n",
+					sym_name, i, n1, n2);
+				return false;
+			}
+			if (m1->offset != m2->offset) {
+				pr_warn("global '%s': incompatible field #%d ('%s') offsets\n",
+					sym_name, i, n1);
+				return false;
+			}
+			if (!glob_sym_btf_matches(sym_name, exact, btf1, m1->type, btf2, m2->type))
+				return false;
+		}
+
+		return true;
+	}
+	case BTF_KIND_FUNC_PROTO: {
+		const struct btf_param *m1, *m2;
+
+		if (btf_vlen(t1) != btf_vlen(t2)) {
+			pr_warn("global '%s': incompatible number of %s params %u and %u\n",
+				sym_name, btf_kind_str(t1), btf_vlen(t1), btf_vlen(t2));
+			return false;
+		}
+
+		n = btf_vlen(t1);
+		m1 = btf_params(t1);
+		m2 = btf_params(t2);
+		for (i = 0; i < n; i++, m1++, m2++) {
+			/* ignore func arg names */
+			if (!glob_sym_btf_matches(sym_name, exact, btf1, m1->type, btf2, m2->type))
+				return false;
+		}
+
+		/* now check return type as well */
+		id1 = t1->type;
+		id2 = t2->type;
+		goto recur;
+	}
+
+	/* skip_mods_and_typedefs() make this impossible */
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	/* DATASECs are never compared with each other */
+	case BTF_KIND_DATASEC:
+	default:
+		pr_warn("global '%s': unsupported BTF kind %s\n",
+			sym_name, btf_kind_str(t1));
+		return false;
+	}
+}
+
+static bool map_defs_match(const char *sym_name,
+			   const struct btf *main_btf,
+			   const struct btf_map_def *main_def,
+			   const struct btf_map_def *main_inner_def,
+			   const struct btf *extra_btf,
+			   const struct btf_map_def *extra_def,
+			   const struct btf_map_def *extra_inner_def)
+{
+	const char *reason;
+
+	if (main_def->map_type != extra_def->map_type) {
+		reason = "type";
+		goto mismatch;
+	}
+
+	/* check key type/size match */
+	if (main_def->key_size != extra_def->key_size) {
+		reason = "key_size";
+		goto mismatch;
+	}
+	if (!!main_def->key_type_id != !!extra_def->key_type_id) {
+		reason = "key type";
+		goto mismatch;
+	}
+	if ((main_def->parts & MAP_DEF_KEY_TYPE)
+	     && !glob_sym_btf_matches(sym_name, true /*exact*/,
+				      main_btf, main_def->key_type_id,
+				      extra_btf, extra_def->key_type_id)) {
+		reason = "key type";
+		goto mismatch;
+	}
+
+	/* validate value type/size match */
+	if (main_def->value_size != extra_def->value_size) {
+		reason = "value_size";
+		goto mismatch;
+	}
+	if (!!main_def->value_type_id != !!extra_def->value_type_id) {
+		reason = "value type";
+		goto mismatch;
+	}
+	if ((main_def->parts & MAP_DEF_VALUE_TYPE)
+	     && !glob_sym_btf_matches(sym_name, true /*exact*/,
+				      main_btf, main_def->value_type_id,
+				      extra_btf, extra_def->value_type_id)) {
+		reason = "key type";
+		goto mismatch;
+	}
+
+	if (main_def->max_entries != extra_def->max_entries) {
+		reason = "max_entries";
+		goto mismatch;
+	}
+	if (main_def->map_flags != extra_def->map_flags) {
+		reason = "map_flags";
+		goto mismatch;
+	}
+	if (main_def->numa_node != extra_def->numa_node) {
+		reason = "numa_node";
+		goto mismatch;
+	}
+	if (main_def->pinning != extra_def->pinning) {
+		reason = "pinning";
+		goto mismatch;
+	}
+
+	if ((main_def->parts & MAP_DEF_INNER_MAP) != (extra_def->parts & MAP_DEF_INNER_MAP)) {
+		reason = "inner map";
+		goto mismatch;
+	}
+
+	if (main_def->parts & MAP_DEF_INNER_MAP) {
+		char inner_map_name[128];
+
+		snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", sym_name);
+
+		return map_defs_match(inner_map_name,
+				      main_btf, main_inner_def, NULL,
+				      extra_btf, extra_inner_def, NULL);
+	}
+
+	return true;
+
+mismatch:
+	pr_warn("global '%s': map %s mismatch\n", sym_name, reason);
+	return false;
+}
+
+static bool glob_map_defs_match(const char *sym_name,
+				struct bpf_linker *linker, struct glob_sym *glob_sym,
+				struct src_obj *obj, Elf64_Sym *sym, int btf_id)
+{
+	struct btf_map_def dst_def = {}, dst_inner_def = {};
+	struct btf_map_def src_def = {}, src_inner_def = {};
+	const struct btf_type *t;
+	int err;
+
+	t = btf__type_by_id(obj->btf, btf_id);
+	if (!btf_is_var(t)) {
+		pr_warn("global '%s': invalid map definition type [%d]\n", sym_name, btf_id);
+		return false;
+	}
+	t = skip_mods_and_typedefs(obj->btf, t->type, NULL);
+
+	err = parse_btf_map_def(sym_name, obj->btf, t, true /*strict*/, &src_def, &src_inner_def);
+	if (err) {
+		pr_warn("global '%s': invalid map definition\n", sym_name);
+		return false;
+	}
+
+	/* re-parse existing map definition */
+	t = btf__type_by_id(linker->btf, glob_sym->btf_id);
+	t = skip_mods_and_typedefs(linker->btf, t->type, NULL);
+	err = parse_btf_map_def(sym_name, linker->btf, t, true /*strict*/, &dst_def, &dst_inner_def);
+	if (err) {
+		/* this should not happen, because we already validated it */
+		pr_warn("global '%s': invalid dst map definition\n", sym_name);
+		return false;
+	}
+
+	/* Currently extern map definition has to be complete and match
+	 * concrete map definition exactly. This restriction might be lifted
+	 * in the future.
+	 */
+	return map_defs_match(sym_name, linker->btf, &dst_def, &dst_inner_def,
+			      obj->btf, &src_def, &src_inner_def);
+}
+
+static bool glob_syms_match(const char *sym_name,
+			    struct bpf_linker *linker, struct glob_sym *glob_sym,
+			    struct src_obj *obj, Elf64_Sym *sym, size_t sym_idx, int btf_id)
+{
+	const struct btf_type *src_t;
+
+	/* if we are dealing with externs, BTF types describing both global
+	 * and extern VARs/FUNCs should be completely present in all files
+	 */
+	if (!glob_sym->btf_id || !btf_id) {
+		pr_warn("BTF info is missing for global symbol '%s'\n", sym_name);
+		return false;
+	}
+
+	src_t = btf__type_by_id(obj->btf, btf_id);
+	if (!btf_is_var(src_t) && !btf_is_func(src_t)) {
+		pr_warn("only extern variables and functions are supported, but got '%s' for '%s'\n",
+			btf_kind_str(src_t), sym_name);
+		return false;
+	}
+
+	/* deal with .maps definitions specially */
+	if (glob_sym->sec_id && strcmp(linker->secs[glob_sym->sec_id].sec_name, MAPS_ELF_SEC) == 0)
+		return glob_map_defs_match(sym_name, linker, glob_sym, obj, sym, btf_id);
+
+	if (!glob_sym_btf_matches(sym_name, true /*exact*/,
+				  linker->btf, glob_sym->btf_id, obj->btf, btf_id))
+		return false;
+
+	return true;
+}
+
+static bool btf_is_non_static(const struct btf_type *t)
+{
+	return (btf_is_var(t) && btf_var(t)->linkage != BTF_VAR_STATIC)
+	       || (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_STATIC);
+}
+
+static int find_glob_sym_btf(struct src_obj *obj, Elf64_Sym *sym, const char *sym_name,
+			     int *out_btf_sec_id, int *out_btf_id)
+{
+	int i, j, n, m, btf_id = 0;
+	const struct btf_type *t;
+	const struct btf_var_secinfo *vi;
+	const char *name;
+
+	if (!obj->btf) {
+		pr_warn("failed to find BTF info for object '%s'\n", obj->filename);
+		return -EINVAL;
+	}
+
+	n = btf__type_cnt(obj->btf);
+	for (i = 1; i < n; i++) {
+		t = btf__type_by_id(obj->btf, i);
+
+		/* some global and extern FUNCs and VARs might not be associated with any
+		 * DATASEC, so try to detect them in the same pass
+		 */
+		if (btf_is_non_static(t)) {
+			name = btf__str_by_offset(obj->btf, t->name_off);
+			if (strcmp(name, sym_name) != 0)
+				continue;
+
+			/* remember and still try to find DATASEC */
+			btf_id = i;
+			continue;
+		}
+
+		if (!btf_is_datasec(t))
+			continue;
+
+		vi = btf_var_secinfos(t);
+		for (j = 0, m = btf_vlen(t); j < m; j++, vi++) {
+			t = btf__type_by_id(obj->btf, vi->type);
+			name = btf__str_by_offset(obj->btf, t->name_off);
+
+			if (strcmp(name, sym_name) != 0)
+				continue;
+			if (btf_is_var(t) && btf_var(t)->linkage == BTF_VAR_STATIC)
+				continue;
+			if (btf_is_func(t) && btf_func_linkage(t) == BTF_FUNC_STATIC)
+				continue;
+
+			if (btf_id && btf_id != vi->type) {
+				pr_warn("global/extern '%s' BTF is ambiguous: both types #%d and #%u match\n",
+					sym_name, btf_id, vi->type);
+				return -EINVAL;
+			}
+
+			*out_btf_sec_id = i;
+			*out_btf_id = vi->type;
+
+			return 0;
+		}
+	}
+
+	/* free-floating extern or global FUNC */
+	if (btf_id) {
+		*out_btf_sec_id = 0;
+		*out_btf_id = btf_id;
+		return 0;
+	}
+
+	pr_warn("failed to find BTF info for global/extern symbol '%s'\n", sym_name);
+	return -ENOENT;
+}
+
+static struct src_sec *find_src_sec_by_name(struct src_obj *obj, const char *sec_name)
+{
+	struct src_sec *sec;
+	int i;
+
+	for (i = 1; i < obj->sec_cnt; i++) {
+		sec = &obj->secs[i];
+
+		if (strcmp(sec->sec_name, sec_name) == 0)
+			return sec;
+	}
+
+	return NULL;
+}
+
+static int complete_extern_btf_info(struct btf *dst_btf, int dst_id,
+				    struct btf *src_btf, int src_id)
+{
+	struct btf_type *dst_t = btf_type_by_id(dst_btf, dst_id);
+	struct btf_type *src_t = btf_type_by_id(src_btf, src_id);
+	struct btf_param *src_p, *dst_p;
+	const char *s;
+	int i, n, off;
+
+	/* We already made sure that source and destination types (FUNC or
+	 * VAR) match in terms of types and argument names.
+	 */
+	if (btf_is_var(dst_t)) {
+		btf_var(dst_t)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
+		return 0;
+	}
+
+	dst_t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_GLOBAL, 0);
+
+	/* now onto FUNC_PROTO types */
+	src_t = btf_type_by_id(src_btf, src_t->type);
+	dst_t = btf_type_by_id(dst_btf, dst_t->type);
+
+	/* Fill in all the argument names, which for extern FUNCs are missing.
+	 * We'll end up with two copies of FUNCs/VARs for externs, but that
+	 * will be taken care of by BTF dedup at the very end.
+	 * It might be that BTF types for extern in one file has less/more BTF
+	 * information (e.g., FWD instead of full STRUCT/UNION information),
+	 * but that should be (in most cases, subject to BTF dedup rules)
+	 * handled and resolved by BTF dedup algorithm as well, so we won't
+	 * worry about it. Our only job is to make sure that argument names
+	 * are populated on both sides, otherwise BTF dedup will pedantically
+	 * consider them different.
+	 */
+	src_p = btf_params(src_t);
+	dst_p = btf_params(dst_t);
+	for (i = 0, n = btf_vlen(dst_t); i < n; i++, src_p++, dst_p++) {
+		if (!src_p->name_off)
+			continue;
+
+		/* src_btf has more complete info, so add name to dst_btf */
+		s = btf__str_by_offset(src_btf, src_p->name_off);
+		off = btf__add_str(dst_btf, s);
+		if (off < 0)
+			return off;
+		dst_p->name_off = off;
+	}
+	return 0;
+}
+
+static void sym_update_bind(Elf64_Sym *sym, int sym_bind)
+{
+	sym->st_info = ELF64_ST_INFO(sym_bind, ELF64_ST_TYPE(sym->st_info));
+}
+
+static void sym_update_type(Elf64_Sym *sym, int sym_type)
+{
+	sym->st_info = ELF64_ST_INFO(ELF64_ST_BIND(sym->st_info), sym_type);
+}
+
+static void sym_update_visibility(Elf64_Sym *sym, int sym_vis)
+{
+	/* libelf doesn't provide setters for ST_VISIBILITY,
+	 * but it is stored in the lower 2 bits of st_other
+	 */
+	sym->st_other &= ~0x03;
+	sym->st_other |= sym_vis;
+}
+
+static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj,
+				 Elf64_Sym *sym, const char *sym_name, int src_sym_idx)
+{
+	struct src_sec *src_sec = NULL;
+	struct dst_sec *dst_sec = NULL;
+	struct glob_sym *glob_sym = NULL;
+	int name_off, sym_type, sym_bind, sym_vis, err;
+	int btf_sec_id = 0, btf_id = 0;
+	size_t dst_sym_idx;
+	Elf64_Sym *dst_sym;
+	bool sym_is_extern;
+
+	sym_type = ELF64_ST_TYPE(sym->st_info);
+	sym_bind = ELF64_ST_BIND(sym->st_info);
+	sym_vis = ELF64_ST_VISIBILITY(sym->st_other);
+	sym_is_extern = sym->st_shndx == SHN_UNDEF;
+
+	if (sym_is_extern) {
+		if (!obj->btf) {
+			pr_warn("externs without BTF info are not supported\n");
+			return -ENOTSUP;
+		}
+	} else if (sym->st_shndx < SHN_LORESERVE) {
+		src_sec = &obj->secs[sym->st_shndx];
+		if (src_sec->skipped)
+			return 0;
+		dst_sec = &linker->secs[src_sec->dst_id];
+
+		/* allow only one STT_SECTION symbol per section */
+		if (sym_type == STT_SECTION && dst_sec->sec_sym_idx) {
+			obj->sym_map[src_sym_idx] = dst_sec->sec_sym_idx;
+			return 0;
+		}
+
+		if (strcmp(src_sec->sec_name, JUMPTABLES_SEC) == 0)
+			goto add_sym;
+	}
+
+	if (sym_bind == STB_LOCAL)
+		goto add_sym;
+
+	/* find matching BTF info */
+	err = find_glob_sym_btf(obj, sym, sym_name, &btf_sec_id, &btf_id);
+	if (err)
+		return err;
+
+	if (sym_is_extern && btf_sec_id) {
+		const char *sec_name = NULL;
+		const struct btf_type *t;
+
+		t = btf__type_by_id(obj->btf, btf_sec_id);
+		sec_name = btf__str_by_offset(obj->btf, t->name_off);
+
+		/* Clang puts unannotated extern vars into
+		 * '.extern' BTF DATASEC. Treat them the same
+		 * as unannotated extern funcs (which are
+		 * currently not put into any DATASECs).
+		 * Those don't have associated src_sec/dst_sec.
+		 */
+		if (strcmp(sec_name, BTF_EXTERN_SEC) != 0) {
+			src_sec = find_src_sec_by_name(obj, sec_name);
+			if (!src_sec) {
+				pr_warn("failed to find matching ELF sec '%s'\n", sec_name);
+				return -ENOENT;
+			}
+			dst_sec = &linker->secs[src_sec->dst_id];
+		}
+	}
+
+	glob_sym = find_glob_sym(linker, sym_name);
+	if (glob_sym) {
+		/* Preventively resolve to existing symbol. This is
+		 * needed for further relocation symbol remapping in
+		 * the next step of linking.
+		 */
+		obj->sym_map[src_sym_idx] = glob_sym->sym_idx;
+
+		/* If both symbols are non-externs, at least one of
+		 * them has to be STB_WEAK, otherwise they are in
+		 * a conflict with each other.
+		 */
+		if (!sym_is_extern && !glob_sym->is_extern
+		    && !glob_sym->is_weak && sym_bind != STB_WEAK) {
+			pr_warn("conflicting non-weak symbol #%d (%s) definition in '%s'\n",
+				src_sym_idx, sym_name, obj->filename);
+			return -EINVAL;
+		}
+
+		if (!glob_syms_match(sym_name, linker, glob_sym, obj, sym, src_sym_idx, btf_id))
+			return -EINVAL;
+
+		dst_sym = get_sym_by_idx(linker, glob_sym->sym_idx);
+
+		/* If new symbol is strong, then force dst_sym to be strong as
+		 * well; this way a mix of weak and non-weak extern
+		 * definitions will end up being strong.
+		 */
+		if (sym_bind == STB_GLOBAL) {
+			/* We still need to preserve type (NOTYPE or
+			 * OBJECT/FUNC, depending on whether the symbol is
+			 * extern or not)
+			 */
+			sym_update_bind(dst_sym, STB_GLOBAL);
+			glob_sym->is_weak = false;
+		}
+
+		/* Non-default visibility is "contaminating", with stricter
+		 * visibility overwriting more permissive ones, even if more
+		 * permissive visibility comes from just an extern definition.
+		 * Currently only STV_DEFAULT and STV_HIDDEN are allowed and
+		 * ensured by ELF symbol sanity checks above.
+		 */
+		if (sym_vis > ELF64_ST_VISIBILITY(dst_sym->st_other))
+			sym_update_visibility(dst_sym, sym_vis);
+
+		/* If the new symbol is extern, then regardless if
+		 * existing symbol is extern or resolved global, just
+		 * keep the existing one untouched.
+		 */
+		if (sym_is_extern)
+			return 0;
+
+		/* If existing symbol is a strong resolved symbol, bail out,
+		 * because we lost resolution battle have nothing to
+		 * contribute. We already checked above that there is no
+		 * strong-strong conflict. We also already tightened binding
+		 * and visibility, so nothing else to contribute at that point.
+		 */
+		if (!glob_sym->is_extern && sym_bind == STB_WEAK)
+			return 0;
+
+		/* At this point, new symbol is strong non-extern,
+		 * so overwrite glob_sym with new symbol information.
+		 * Preserve binding and visibility.
+		 */
+		sym_update_type(dst_sym, sym_type);
+		dst_sym->st_shndx = dst_sec->sec_idx;
+		dst_sym->st_value = src_sec->dst_off + sym->st_value;
+		dst_sym->st_size = sym->st_size;
+
+		/* see comment below about dst_sec->id vs dst_sec->sec_idx */
+		glob_sym->sec_id = dst_sec->id;
+		glob_sym->is_extern = false;
+
+		if (complete_extern_btf_info(linker->btf, glob_sym->btf_id,
+					     obj->btf, btf_id))
+			return -EINVAL;
+
+		/* request updating VAR's/FUNC's underlying BTF type when appending BTF type */
+		glob_sym->underlying_btf_id = 0;
+
+		obj->sym_map[src_sym_idx] = glob_sym->sym_idx;
+		return 0;
+	}
+
+add_sym:
+	name_off = strset__add_str(linker->strtab_strs, sym_name);
+	if (name_off < 0)
+		return name_off;
+
+	dst_sym = add_new_sym(linker, &dst_sym_idx);
+	if (!dst_sym)
+		return -ENOMEM;
+
+	dst_sym->st_name = name_off;
+	dst_sym->st_info = sym->st_info;
+	dst_sym->st_other = sym->st_other;
+	dst_sym->st_shndx = dst_sec ? dst_sec->sec_idx : sym->st_shndx;
+	dst_sym->st_value = (src_sec ? src_sec->dst_off : 0) + sym->st_value;
+	dst_sym->st_size = sym->st_size;
+
+	obj->sym_map[src_sym_idx] = dst_sym_idx;
+
+	if (sym_type == STT_SECTION && dst_sec) {
+		dst_sec->sec_sym_idx = dst_sym_idx;
+		dst_sym->st_value = 0;
+	}
+
+	if (sym_bind != STB_LOCAL) {
+		glob_sym = add_glob_sym(linker);
+		if (!glob_sym)
+			return -ENOMEM;
+
+		glob_sym->sym_idx = dst_sym_idx;
+		/* we use dst_sec->id (and not dst_sec->sec_idx), because
+		 * ephemeral sections (.kconfig, .ksyms, etc) don't have
+		 * sec_idx (as they don't have corresponding ELF section), but
+		 * still have id. .extern doesn't have even ephemeral section
+		 * associated with it, so dst_sec->id == dst_sec->sec_idx == 0.
+		 */
+		glob_sym->sec_id = dst_sec ? dst_sec->id : 0;
+		glob_sym->name_off = name_off;
+		/* we will fill btf_id in during BTF merging step */
+		glob_sym->btf_id = 0;
+		glob_sym->is_extern = sym_is_extern;
+		glob_sym->is_weak = sym_bind == STB_WEAK;
+	}
+
+	return 0;
+}
+
+static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *obj)
+{
+	struct src_sec *src_symtab = &obj->secs[obj->symtab_sec_idx];
+	int i, err;
+
+	for (i = 1; i < obj->sec_cnt; i++) {
+		struct src_sec *src_sec, *src_linked_sec;
+		struct dst_sec *dst_sec, *dst_linked_sec;
+		Elf64_Rel *src_rel, *dst_rel;
+		int j, n;
+
+		src_sec = &obj->secs[i];
+		if (!is_relo_sec(src_sec))
+			continue;
+
+		/* shdr->sh_info points to relocatable section */
+		src_linked_sec = &obj->secs[src_sec->shdr->sh_info];
+		if (src_linked_sec->skipped)
+			continue;
+
+		dst_sec = find_dst_sec_by_name(linker, src_sec->sec_name);
+		if (!dst_sec) {
+			dst_sec = add_dst_sec(linker, src_sec->sec_name);
+			if (!dst_sec)
+				return -ENOMEM;
+			err = init_sec(linker, dst_sec, src_sec);
+			if (err) {
+				pr_warn("failed to init section '%s'\n", src_sec->sec_name);
+				return err;
+			}
+		} else if (!secs_match(dst_sec, src_sec)) {
+			pr_warn("sections %s are not compatible\n", src_sec->sec_name);
+			return -EINVAL;
+		}
+
+		/* shdr->sh_link points to SYMTAB */
+		dst_sec->shdr->sh_link = linker->symtab_sec_idx;
+
+		/* shdr->sh_info points to relocated section */
+		dst_linked_sec = &linker->secs[src_linked_sec->dst_id];
+		dst_sec->shdr->sh_info = dst_linked_sec->sec_idx;
+
+		src_sec->dst_id = dst_sec->id;
+		err = extend_sec(linker, dst_sec, src_sec);
+		if (err)
+			return err;
+
+		src_rel = src_sec->data->d_buf;
+		dst_rel = dst_sec->raw_data + src_sec->dst_off;
+		n = src_sec->shdr->sh_size / src_sec->shdr->sh_entsize;
+		for (j = 0; j < n; j++, src_rel++, dst_rel++) {
+			size_t src_sym_idx, dst_sym_idx, sym_type;
+			Elf64_Sym *src_sym;
+
+			src_sym_idx = ELF64_R_SYM(src_rel->r_info);
+			src_sym = src_symtab->data->d_buf + sizeof(*src_sym) * src_sym_idx;
+
+			dst_sym_idx = obj->sym_map[src_sym_idx];
+			dst_rel->r_offset += src_linked_sec->dst_off;
+			sym_type = ELF64_R_TYPE(src_rel->r_info);
+			dst_rel->r_info = ELF64_R_INFO(dst_sym_idx, sym_type);
+
+			if (ELF64_ST_TYPE(src_sym->st_info) == STT_SECTION) {
+				struct src_sec *sec = &obj->secs[src_sym->st_shndx];
+				struct bpf_insn *insn;
+
+				if (src_linked_sec->shdr->sh_flags & SHF_EXECINSTR) {
+					/* calls to the very first static function inside
+					 * .text section at offset 0 will
+					 * reference section symbol, not the
+					 * function symbol. Fix that up,
+					 * otherwise it won't be possible to
+					 * relocate calls to two different
+					 * static functions with the same name
+					 * (rom two different object files)
+					 */
+					insn = dst_linked_sec->raw_data + dst_rel->r_offset;
+					if (insn->code == (BPF_JMP | BPF_CALL))
+						insn->imm += sec->dst_off / sizeof(struct bpf_insn);
+					else
+						insn->imm += sec->dst_off;
+				} else {
+					pr_warn("relocation against STT_SECTION in non-exec section is not supported!\n");
+					return -EINVAL;
+				}
+			}
+
+		}
+	}
+
+	return 0;
+}
+
+static Elf64_Sym *find_sym_by_name(struct src_obj *obj, size_t sec_idx,
+				   int sym_type, const char *sym_name)
+{
+	struct src_sec *symtab = &obj->secs[obj->symtab_sec_idx];
+	Elf64_Sym *sym = symtab->data->d_buf;
+	int i, n = symtab->shdr->sh_size / symtab->shdr->sh_entsize;
+	int str_sec_idx = symtab->shdr->sh_link;
+	const char *name;
+
+	for (i = 0; i < n; i++, sym++) {
+		if (sym->st_shndx != sec_idx)
+			continue;
+		if (ELF64_ST_TYPE(sym->st_info) != sym_type)
+			continue;
+
+		name = elf_strptr(obj->elf, str_sec_idx, sym->st_name);
+		if (!name)
+			return NULL;
+
+		if (strcmp(sym_name, name) != 0)
+			continue;
+
+		return sym;
+	}
+
+	return NULL;
+}
+
+static int linker_fixup_btf(struct src_obj *obj)
+{
+	const char *sec_name;
+	struct src_sec *sec;
+	int i, j, n, m;
+
+	if (!obj->btf)
+		return 0;
+
+	n = btf__type_cnt(obj->btf);
+	for (i = 1; i < n; i++) {
+		struct btf_var_secinfo *vi;
+		struct btf_type *t;
+
+		t = btf_type_by_id(obj->btf, i);
+		if (btf_kind(t) != BTF_KIND_DATASEC)
+			continue;
+
+		sec_name = btf__str_by_offset(obj->btf, t->name_off);
+		sec = find_src_sec_by_name(obj, sec_name);
+		if (sec) {
+			/* record actual section size, unless ephemeral */
+			if (sec->shdr)
+				t->size = sec->shdr->sh_size;
+		} else {
+			/* BTF can have some sections that are not represented
+			 * in ELF, e.g., .kconfig, .ksyms, .extern, which are used
+			 * for special extern variables.
+			 *
+			 * For all but one such special (ephemeral)
+			 * sections, we pre-create "section shells" to be able
+			 * to keep track of extra per-section metadata later
+			 * (e.g., those BTF extern variables).
+			 *
+			 * .extern is even more special, though, because it
+			 * contains extern variables that need to be resolved
+			 * by static linker, not libbpf and kernel. When such
+			 * externs are resolved, we are going to remove them
+			 * from .extern BTF section and might end up not
+			 * needing it at all. Each resolved extern should have
+			 * matching non-extern VAR/FUNC in other sections.
+			 *
+			 * We do support leaving some of the externs
+			 * unresolved, though, to support cases of building
+			 * libraries, which will later be linked against final
+			 * BPF applications. So if at finalization we still
+			 * see unresolved externs, we'll create .extern
+			 * section on our own.
+			 */
+			if (strcmp(sec_name, BTF_EXTERN_SEC) == 0)
+				continue;
+
+			sec = add_src_sec(obj, sec_name);
+			if (!sec)
+				return -ENOMEM;
+
+			sec->ephemeral = true;
+			sec->sec_idx = 0; /* will match UNDEF shndx in ELF */
+		}
+
+		/* remember ELF section and its BTF type ID match */
+		sec->sec_type_id = i;
+
+		/* fix up variable offsets */
+		vi = btf_var_secinfos(t);
+		for (j = 0, m = btf_vlen(t); j < m; j++, vi++) {
+			const struct btf_type *vt = btf__type_by_id(obj->btf, vi->type);
+			const char *var_name;
+			int var_linkage;
+			Elf64_Sym *sym;
+
+			/* could be a variable or function */
+			if (!btf_is_var(vt))
+				continue;
+
+			var_name = btf__str_by_offset(obj->btf, vt->name_off);
+			var_linkage = btf_var(vt)->linkage;
+
+			/* no need to patch up static or extern vars */
+			if (var_linkage != BTF_VAR_GLOBAL_ALLOCATED)
+				continue;
+
+			sym = find_sym_by_name(obj, sec->sec_idx, STT_OBJECT, var_name);
+			if (!sym) {
+				pr_warn("failed to find symbol for variable '%s' in section '%s'\n", var_name, sec_name);
+				return -ENOENT;
+			}
+
+			vi->offset = sym->st_value;
+		}
+	}
+
+	return 0;
+}
+
+static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj)
+{
+	const struct btf_type *t;
+	int i, j, n, start_id, id, err;
+	const char *name;
+
+	if (!obj->btf)
+		return 0;
+
+	start_id = btf__type_cnt(linker->btf);
+	n = btf__type_cnt(obj->btf);
+
+	obj->btf_type_map = calloc(n + 1, sizeof(int));
+	if (!obj->btf_type_map)
+		return -ENOMEM;
+
+	for (i = 1; i < n; i++) {
+		struct glob_sym *glob_sym = NULL;
+
+		t = btf__type_by_id(obj->btf, i);
+
+		/* DATASECs are handled specially below */
+		if (btf_kind(t) == BTF_KIND_DATASEC)
+			continue;
+
+		if (btf_is_non_static(t)) {
+			/* there should be glob_sym already */
+			name = btf__str_by_offset(obj->btf, t->name_off);
+			glob_sym = find_glob_sym(linker, name);
+
+			/* VARs without corresponding glob_sym are those that
+			 * belong to skipped/deduplicated sections (i.e.,
+			 * license and version), so just skip them
+			 */
+			if (!glob_sym)
+				continue;
+
+			/* linker_append_elf_sym() might have requested
+			 * updating underlying type ID, if extern was resolved
+			 * to strong symbol or weak got upgraded to non-weak
+			 */
+			if (glob_sym->underlying_btf_id == 0)
+				glob_sym->underlying_btf_id = -t->type;
+
+			/* globals from previous object files that match our
+			 * VAR/FUNC already have a corresponding associated
+			 * BTF type, so just make sure to use it
+			 */
+			if (glob_sym->btf_id) {
+				/* reuse existing BTF type for global var/func */
+				obj->btf_type_map[i] = glob_sym->btf_id;
+				continue;
+			}
+		}
+
+		id = btf__add_type(linker->btf, obj->btf, t);
+		if (id < 0) {
+			pr_warn("failed to append BTF type #%d from file '%s'\n", i, obj->filename);
+			return id;
+		}
+
+		obj->btf_type_map[i] = id;
+
+		/* record just appended BTF type for var/func */
+		if (glob_sym) {
+			glob_sym->btf_id = id;
+			glob_sym->underlying_btf_id = -t->type;
+		}
+	}
+
+	/* remap all the types except DATASECs */
+	n = btf__type_cnt(linker->btf);
+	for (i = start_id; i < n; i++) {
+		struct btf_type *dst_t = btf_type_by_id(linker->btf, i);
+		struct btf_field_iter it;
+		__u32 *type_id;
+
+		err = btf_field_iter_init(&it, dst_t, BTF_FIELD_ITER_IDS);
+		if (err)
+			return err;
+
+		while ((type_id = btf_field_iter_next(&it))) {
+			int new_id = obj->btf_type_map[*type_id];
+
+			/* Error out if the type wasn't remapped. Ignore VOID which stays VOID. */
+			if (new_id == 0 && *type_id != 0) {
+				pr_warn("failed to find new ID mapping for original BTF type ID %u\n",
+					*type_id);
+				return -EINVAL;
+			}
+
+			*type_id = obj->btf_type_map[*type_id];
+		}
+	}
+
+	/* Rewrite VAR/FUNC underlying types (i.e., FUNC's FUNC_PROTO and VAR's
+	 * actual type), if necessary
+	 */
+	for (i = 0; i < linker->glob_sym_cnt; i++) {
+		struct glob_sym *glob_sym = &linker->glob_syms[i];
+		struct btf_type *glob_t;
+
+		if (glob_sym->underlying_btf_id >= 0)
+			continue;
+
+		glob_sym->underlying_btf_id = obj->btf_type_map[-glob_sym->underlying_btf_id];
+
+		glob_t = btf_type_by_id(linker->btf, glob_sym->btf_id);
+		glob_t->type = glob_sym->underlying_btf_id;
+	}
+
+	/* append DATASEC info */
+	for (i = 1; i < obj->sec_cnt; i++) {
+		struct src_sec *src_sec;
+		struct dst_sec *dst_sec;
+		const struct btf_var_secinfo *src_var;
+		struct btf_var_secinfo *dst_var;
+
+		src_sec = &obj->secs[i];
+		if (!src_sec->sec_type_id || src_sec->skipped)
+			continue;
+		dst_sec = &linker->secs[src_sec->dst_id];
+
+		/* Mark section as having BTF regardless of the presence of
+		 * variables. In some cases compiler might generate empty BTF
+		 * with no variables information. E.g., when promoting local
+		 * array/structure variable initial values and BPF object
+		 * file otherwise has no read-only static variables in
+		 * .rodata. We need to preserve such empty BTF and just set
+		 * correct section size.
+		 */
+		dst_sec->has_btf = true;
+
+		t = btf__type_by_id(obj->btf, src_sec->sec_type_id);
+		src_var = btf_var_secinfos(t);
+		n = btf_vlen(t);
+		for (j = 0; j < n; j++, src_var++) {
+			void *sec_vars = dst_sec->sec_vars;
+			int new_id = obj->btf_type_map[src_var->type];
+			struct glob_sym *glob_sym = NULL;
+
+			t = btf_type_by_id(linker->btf, new_id);
+			if (btf_is_non_static(t)) {
+				name = btf__str_by_offset(linker->btf, t->name_off);
+				glob_sym = find_glob_sym(linker, name);
+				if (glob_sym->sec_id != dst_sec->id) {
+					pr_warn("global '%s': section mismatch %d vs %d\n",
+						name, glob_sym->sec_id, dst_sec->id);
+					return -EINVAL;
+				}
+			}
+
+			/* If there is already a member (VAR or FUNC) mapped
+			 * to the same type, don't add a duplicate entry.
+			 * This will happen when multiple object files define
+			 * the same extern VARs/FUNCs.
+			 */
+			if (glob_sym && glob_sym->var_idx >= 0) {
+				__s64 sz;
+
+				/* FUNCs don't have size, nothing to update */
+				if (btf_is_func(t))
+					continue;
+
+				dst_var = &dst_sec->sec_vars[glob_sym->var_idx];
+				/* Because underlying BTF type might have
+				 * changed, so might its size have changed, so
+				 * re-calculate and update it in sec_var.
+				 */
+				sz = btf__resolve_size(linker->btf, glob_sym->underlying_btf_id);
+				if (sz < 0) {
+					pr_warn("global '%s': failed to resolve size of underlying type: %d\n",
+						name, (int)sz);
+					return -EINVAL;
+				}
+				dst_var->size = sz;
+				continue;
+			}
+
+			sec_vars = libbpf_reallocarray(sec_vars,
+						       dst_sec->sec_var_cnt + 1,
+						       sizeof(*dst_sec->sec_vars));
+			if (!sec_vars)
+				return -ENOMEM;
+
+			dst_sec->sec_vars = sec_vars;
+			dst_sec->sec_var_cnt++;
+
+			dst_var = &dst_sec->sec_vars[dst_sec->sec_var_cnt - 1];
+			dst_var->type = obj->btf_type_map[src_var->type];
+			dst_var->size = src_var->size;
+			dst_var->offset = src_sec->dst_off + src_var->offset;
+
+			if (glob_sym)
+				glob_sym->var_idx = dst_sec->sec_var_cnt - 1;
+		}
+	}
+
+	return 0;
+}
+
+static void *add_btf_ext_rec(struct btf_ext_sec_data *ext_data, const void *src_rec)
+{
+	void *tmp;
+
+	tmp = libbpf_reallocarray(ext_data->recs, ext_data->rec_cnt + 1, ext_data->rec_sz);
+	if (!tmp)
+		return NULL;
+	ext_data->recs = tmp;
+
+	tmp += ext_data->rec_cnt * ext_data->rec_sz;
+	memcpy(tmp, src_rec, ext_data->rec_sz);
+
+	ext_data->rec_cnt++;
+
+	return tmp;
+}
+
+static int linker_append_btf_ext(struct bpf_linker *linker, struct src_obj *obj)
+{
+	const struct btf_ext_info_sec *ext_sec;
+	const char *sec_name, *s;
+	struct src_sec *src_sec;
+	struct dst_sec *dst_sec;
+	int rec_sz, str_off, i;
+
+	if (!obj->btf_ext)
+		return 0;
+
+	rec_sz = obj->btf_ext->func_info.rec_size;
+	for_each_btf_ext_sec(&obj->btf_ext->func_info, ext_sec) {
+		struct bpf_func_info_min *src_rec, *dst_rec;
+
+		sec_name = btf__name_by_offset(obj->btf, ext_sec->sec_name_off);
+		src_sec = find_src_sec_by_name(obj, sec_name);
+		if (!src_sec) {
+			pr_warn("can't find section '%s' referenced from .BTF.ext\n", sec_name);
+			return -EINVAL;
+		}
+		dst_sec = &linker->secs[src_sec->dst_id];
+
+		if (dst_sec->func_info.rec_sz == 0)
+			dst_sec->func_info.rec_sz = rec_sz;
+		if (dst_sec->func_info.rec_sz != rec_sz) {
+			pr_warn("incompatible .BTF.ext record sizes for section '%s'\n", sec_name);
+			return -EINVAL;
+		}
+
+		for_each_btf_ext_rec(&obj->btf_ext->func_info, ext_sec, i, src_rec) {
+			dst_rec = add_btf_ext_rec(&dst_sec->func_info, src_rec);
+			if (!dst_rec)
+				return -ENOMEM;
+
+			dst_rec->insn_off += src_sec->dst_off;
+			dst_rec->type_id = obj->btf_type_map[dst_rec->type_id];
+		}
+	}
+
+	rec_sz = obj->btf_ext->line_info.rec_size;
+	for_each_btf_ext_sec(&obj->btf_ext->line_info, ext_sec) {
+		struct bpf_line_info_min *src_rec, *dst_rec;
+
+		sec_name = btf__name_by_offset(obj->btf, ext_sec->sec_name_off);
+		src_sec = find_src_sec_by_name(obj, sec_name);
+		if (!src_sec) {
+			pr_warn("can't find section '%s' referenced from .BTF.ext\n", sec_name);
+			return -EINVAL;
+		}
+		dst_sec = &linker->secs[src_sec->dst_id];
+
+		if (dst_sec->line_info.rec_sz == 0)
+			dst_sec->line_info.rec_sz = rec_sz;
+		if (dst_sec->line_info.rec_sz != rec_sz) {
+			pr_warn("incompatible .BTF.ext record sizes for section '%s'\n", sec_name);
+			return -EINVAL;
+		}
+
+		for_each_btf_ext_rec(&obj->btf_ext->line_info, ext_sec, i, src_rec) {
+			dst_rec = add_btf_ext_rec(&dst_sec->line_info, src_rec);
+			if (!dst_rec)
+				return -ENOMEM;
+
+			dst_rec->insn_off += src_sec->dst_off;
+
+			s = btf__str_by_offset(obj->btf, src_rec->file_name_off);
+			str_off = btf__add_str(linker->btf, s);
+			if (str_off < 0)
+				return -ENOMEM;
+			dst_rec->file_name_off = str_off;
+
+			s = btf__str_by_offset(obj->btf, src_rec->line_off);
+			str_off = btf__add_str(linker->btf, s);
+			if (str_off < 0)
+				return -ENOMEM;
+			dst_rec->line_off = str_off;
+
+			/* dst_rec->line_col is fine */
+		}
+	}
+
+	rec_sz = obj->btf_ext->core_relo_info.rec_size;
+	for_each_btf_ext_sec(&obj->btf_ext->core_relo_info, ext_sec) {
+		struct bpf_core_relo *src_rec, *dst_rec;
+
+		sec_name = btf__name_by_offset(obj->btf, ext_sec->sec_name_off);
+		src_sec = find_src_sec_by_name(obj, sec_name);
+		if (!src_sec) {
+			pr_warn("can't find section '%s' referenced from .BTF.ext\n", sec_name);
+			return -EINVAL;
+		}
+		dst_sec = &linker->secs[src_sec->dst_id];
+
+		if (dst_sec->core_relo_info.rec_sz == 0)
+			dst_sec->core_relo_info.rec_sz = rec_sz;
+		if (dst_sec->core_relo_info.rec_sz != rec_sz) {
+			pr_warn("incompatible .BTF.ext record sizes for section '%s'\n", sec_name);
+			return -EINVAL;
+		}
+
+		for_each_btf_ext_rec(&obj->btf_ext->core_relo_info, ext_sec, i, src_rec) {
+			dst_rec = add_btf_ext_rec(&dst_sec->core_relo_info, src_rec);
+			if (!dst_rec)
+				return -ENOMEM;
+
+			dst_rec->insn_off += src_sec->dst_off;
+			dst_rec->type_id = obj->btf_type_map[dst_rec->type_id];
+
+			s = btf__str_by_offset(obj->btf, src_rec->access_str_off);
+			str_off = btf__add_str(linker->btf, s);
+			if (str_off < 0)
+				return -ENOMEM;
+			dst_rec->access_str_off = str_off;
+
+			/* dst_rec->kind is fine */
+		}
+	}
+
+	return 0;
+}
+
+int bpf_linker__finalize(struct bpf_linker *linker)
+{
+	struct dst_sec *sec;
+	size_t strs_sz;
+	const void *strs;
+	int err, i;
+
+	if (!linker->elf)
+		return libbpf_err(-EINVAL);
+
+	err = finalize_btf(linker);
+	if (err)
+		return libbpf_err(err);
+
+	/* Finalize strings */
+	strs_sz = strset__data_size(linker->strtab_strs);
+	strs = strset__data(linker->strtab_strs);
+
+	sec = &linker->secs[linker->strtab_sec_idx];
+	sec->data->d_align = 1;
+	sec->data->d_off = 0LL;
+	sec->data->d_buf = (void *)strs;
+	sec->data->d_type = ELF_T_BYTE;
+	sec->data->d_size = strs_sz;
+	sec->shdr->sh_size = strs_sz;
+
+	for (i = 1; i < linker->sec_cnt; i++) {
+		sec = &linker->secs[i];
+
+		/* STRTAB is handled specially above */
+		if (sec->sec_idx == linker->strtab_sec_idx)
+			continue;
+
+		/* special ephemeral sections (.ksyms, .kconfig, etc) */
+		if (!sec->scn)
+			continue;
+
+		/* restore sections with bpf insns to target byte-order */
+		if (linker->swapped_endian && is_exec_sec(sec))
+			exec_sec_bswap(sec->raw_data, sec->sec_sz);
+
+		sec->data->d_buf = sec->raw_data;
+	}
+
+	/* Finalize ELF layout */
+	if (elf_update(linker->elf, ELF_C_NULL) < 0) {
+		err = -EINVAL;
+		pr_warn_elf("failed to finalize ELF layout");
+		return libbpf_err(err);
+	}
+
+	/* Write out final ELF contents */
+	if (elf_update(linker->elf, ELF_C_WRITE) < 0) {
+		err = -EINVAL;
+		pr_warn_elf("failed to write ELF contents");
+		return libbpf_err(err);
+	}
+
+	elf_end(linker->elf);
+	linker->elf = NULL;
+
+	if (linker->fd_is_owned)
+		close(linker->fd);
+	linker->fd = -1;
+
+	return 0;
+}
+
+static int emit_elf_data_sec(struct bpf_linker *linker, const char *sec_name,
+			     size_t align, const void *raw_data, size_t raw_sz)
+{
+	Elf_Scn *scn;
+	Elf_Data *data;
+	Elf64_Shdr *shdr;
+	int name_off;
+
+	name_off = strset__add_str(linker->strtab_strs, sec_name);
+	if (name_off < 0)
+		return name_off;
+
+	scn = elf_newscn(linker->elf);
+	if (!scn)
+		return -ENOMEM;
+	data = elf_newdata(scn);
+	if (!data)
+		return -ENOMEM;
+	shdr = elf64_getshdr(scn);
+	if (!shdr)
+		return -EINVAL;
+
+	shdr->sh_name = name_off;
+	shdr->sh_type = SHT_PROGBITS;
+	shdr->sh_flags = 0;
+	shdr->sh_size = raw_sz;
+	shdr->sh_link = 0;
+	shdr->sh_info = 0;
+	shdr->sh_addralign = align;
+	shdr->sh_entsize = 0;
+
+	data->d_type = ELF_T_BYTE;
+	data->d_size = raw_sz;
+	data->d_buf = (void *)raw_data;
+	data->d_align = align;
+	data->d_off = 0;
+
+	return 0;
+}
+
+static int finalize_btf(struct bpf_linker *linker)
+{
+	enum btf_endianness link_endianness;
+	LIBBPF_OPTS(btf_dedup_opts, opts);
+	struct btf *btf = linker->btf;
+	const void *raw_data;
+	int i, j, id, err;
+	__u32 raw_sz;
+
+	/* bail out if no BTF data was produced */
+	if (btf__type_cnt(linker->btf) == 1)
+		return 0;
+
+	for (i = 1; i < linker->sec_cnt; i++) {
+		struct dst_sec *sec = &linker->secs[i];
+
+		if (!sec->has_btf)
+			continue;
+
+		id = btf__add_datasec(btf, sec->sec_name, sec->sec_sz);
+		if (id < 0) {
+			pr_warn("failed to add consolidated BTF type for datasec '%s': %d\n",
+				sec->sec_name, id);
+			return id;
+		}
+
+		for (j = 0; j < sec->sec_var_cnt; j++) {
+			struct btf_var_secinfo *vi = &sec->sec_vars[j];
+
+			if (btf__add_datasec_var_info(btf, vi->type, vi->offset, vi->size))
+				return -EINVAL;
+		}
+	}
+
+	err = finalize_btf_ext(linker);
+	if (err) {
+		pr_warn(".BTF.ext generation failed: %s\n", errstr(err));
+		return err;
+	}
+
+	opts.btf_ext = linker->btf_ext;
+	err = btf__dedup(linker->btf, &opts);
+	if (err) {
+		pr_warn("BTF dedup failed: %s\n", errstr(err));
+		return err;
+	}
+
+	/* Set .BTF and .BTF.ext output byte order */
+	link_endianness = linker->elf_hdr->e_ident[EI_DATA] == ELFDATA2MSB ?
+			  BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
+	btf__set_endianness(linker->btf, link_endianness);
+	if (linker->btf_ext)
+		btf_ext__set_endianness(linker->btf_ext, link_endianness);
+
+	/* Emit .BTF section */
+	raw_data = btf__raw_data(linker->btf, &raw_sz);
+	if (!raw_data)
+		return -ENOMEM;
+
+	err = emit_elf_data_sec(linker, BTF_ELF_SEC, 8, raw_data, raw_sz);
+	if (err) {
+		pr_warn("failed to write out .BTF ELF section: %s\n", errstr(err));
+		return err;
+	}
+
+	/* Emit .BTF.ext section */
+	if (linker->btf_ext) {
+		raw_data = btf_ext__raw_data(linker->btf_ext, &raw_sz);
+		if (!raw_data)
+			return -ENOMEM;
+
+		err = emit_elf_data_sec(linker, BTF_EXT_ELF_SEC, 8, raw_data, raw_sz);
+		if (err) {
+			pr_warn("failed to write out .BTF.ext ELF section: %s\n", errstr(err));
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int emit_btf_ext_data(struct bpf_linker *linker, void *output,
+			     const char *sec_name, struct btf_ext_sec_data *sec_data)
+{
+	struct btf_ext_info_sec *sec_info;
+	void *cur = output;
+	int str_off;
+	size_t sz;
+
+	if (!sec_data->rec_cnt)
+		return 0;
+
+	str_off = btf__add_str(linker->btf, sec_name);
+	if (str_off < 0)
+		return -ENOMEM;
+
+	sec_info = cur;
+	sec_info->sec_name_off = str_off;
+	sec_info->num_info = sec_data->rec_cnt;
+	cur += sizeof(struct btf_ext_info_sec);
+
+	sz = sec_data->rec_cnt * sec_data->rec_sz;
+	memcpy(cur, sec_data->recs, sz);
+	cur += sz;
+
+	return cur - output;
+}
+
+static int finalize_btf_ext(struct bpf_linker *linker)
+{
+	size_t funcs_sz = 0, lines_sz = 0, core_relos_sz = 0, total_sz = 0;
+	size_t func_rec_sz = 0, line_rec_sz = 0, core_relo_rec_sz = 0;
+	struct btf_ext_header *hdr;
+	void *data, *cur;
+	int i, err, sz;
+
+	/* validate that all sections have the same .BTF.ext record sizes
+	 * and calculate total data size for each type of data (func info,
+	 * line info, core relos)
+	 */
+	for (i = 1; i < linker->sec_cnt; i++) {
+		struct dst_sec *sec = &linker->secs[i];
+
+		if (sec->func_info.rec_cnt) {
+			if (func_rec_sz == 0)
+				func_rec_sz = sec->func_info.rec_sz;
+			if (func_rec_sz != sec->func_info.rec_sz) {
+				pr_warn("mismatch in func_info record size %zu != %u\n",
+					func_rec_sz, sec->func_info.rec_sz);
+				return -EINVAL;
+			}
+
+			funcs_sz += sizeof(struct btf_ext_info_sec) + func_rec_sz * sec->func_info.rec_cnt;
+		}
+		if (sec->line_info.rec_cnt) {
+			if (line_rec_sz == 0)
+				line_rec_sz = sec->line_info.rec_sz;
+			if (line_rec_sz != sec->line_info.rec_sz) {
+				pr_warn("mismatch in line_info record size %zu != %u\n",
+					line_rec_sz, sec->line_info.rec_sz);
+				return -EINVAL;
+			}
+
+			lines_sz += sizeof(struct btf_ext_info_sec) + line_rec_sz * sec->line_info.rec_cnt;
+		}
+		if (sec->core_relo_info.rec_cnt) {
+			if (core_relo_rec_sz == 0)
+				core_relo_rec_sz = sec->core_relo_info.rec_sz;
+			if (core_relo_rec_sz != sec->core_relo_info.rec_sz) {
+				pr_warn("mismatch in core_relo_info record size %zu != %u\n",
+					core_relo_rec_sz, sec->core_relo_info.rec_sz);
+				return -EINVAL;
+			}
+
+			core_relos_sz += sizeof(struct btf_ext_info_sec) + core_relo_rec_sz * sec->core_relo_info.rec_cnt;
+		}
+	}
+
+	if (!funcs_sz && !lines_sz && !core_relos_sz)
+		return 0;
+
+	total_sz += sizeof(struct btf_ext_header);
+	if (funcs_sz) {
+		funcs_sz += sizeof(__u32); /* record size prefix */
+		total_sz += funcs_sz;
+	}
+	if (lines_sz) {
+		lines_sz += sizeof(__u32); /* record size prefix */
+		total_sz += lines_sz;
+	}
+	if (core_relos_sz) {
+		core_relos_sz += sizeof(__u32); /* record size prefix */
+		total_sz += core_relos_sz;
+	}
+
+	cur = data = calloc(1, total_sz);
+	if (!data)
+		return -ENOMEM;
+
+	hdr = cur;
+	hdr->magic = BTF_MAGIC;
+	hdr->version = BTF_VERSION;
+	hdr->flags = 0;
+	hdr->hdr_len = sizeof(struct btf_ext_header);
+	cur += sizeof(struct btf_ext_header);
+
+	/* All offsets are in bytes relative to the end of this header */
+	hdr->func_info_off = 0;
+	hdr->func_info_len = funcs_sz;
+	hdr->line_info_off = funcs_sz;
+	hdr->line_info_len = lines_sz;
+	hdr->core_relo_off = funcs_sz + lines_sz;
+	hdr->core_relo_len = core_relos_sz;
+
+	if (funcs_sz) {
+		*(__u32 *)cur = func_rec_sz;
+		cur += sizeof(__u32);
+
+		for (i = 1; i < linker->sec_cnt; i++) {
+			struct dst_sec *sec = &linker->secs[i];
+
+			sz = emit_btf_ext_data(linker, cur, sec->sec_name, &sec->func_info);
+			if (sz < 0) {
+				err = sz;
+				goto out;
+			}
+
+			cur += sz;
+		}
+	}
+
+	if (lines_sz) {
+		*(__u32 *)cur = line_rec_sz;
+		cur += sizeof(__u32);
+
+		for (i = 1; i < linker->sec_cnt; i++) {
+			struct dst_sec *sec = &linker->secs[i];
+
+			sz = emit_btf_ext_data(linker, cur, sec->sec_name, &sec->line_info);
+			if (sz < 0) {
+				err = sz;
+				goto out;
+			}
+
+			cur += sz;
+		}
+	}
+
+	if (core_relos_sz) {
+		*(__u32 *)cur = core_relo_rec_sz;
+		cur += sizeof(__u32);
+
+		for (i = 1; i < linker->sec_cnt; i++) {
+			struct dst_sec *sec = &linker->secs[i];
+
+			sz = emit_btf_ext_data(linker, cur, sec->sec_name, &sec->core_relo_info);
+			if (sz < 0) {
+				err = sz;
+				goto out;
+			}
+
+			cur += sz;
+		}
+	}
+
+	linker->btf_ext = btf_ext__new(data, total_sz);
+	err = libbpf_get_error(linker->btf_ext);
+	if (err) {
+		linker->btf_ext = NULL;
+		pr_warn("failed to parse final .BTF.ext data: %s\n", errstr(err));
+		goto out;
+	}
+
+out:
+	free(data);
+	return err;
+}
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
new file mode 100644
index 000000000..c9a78fb16
--- /dev/null
+++ b/tools/lib/bpf/netlink.c
@@ -0,0 +1,938 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2018 Facebook */
+
+#include <stdlib.h>
+#include <memory.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <linux/pkt_cls.h>
+#include <linux/rtnetlink.h>
+#include <linux/netdev.h>
+#include <sys/socket.h>
+#include <errno.h>
+#include <time.h>
+
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_internal.h"
+#include "nlattr.h"
+
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
+typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
+
+typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,
+			      void *cookie);
+
+struct xdp_link_info {
+	__u32 prog_id;
+	__u32 drv_prog_id;
+	__u32 hw_prog_id;
+	__u32 skb_prog_id;
+	__u8 attach_mode;
+};
+
+struct xdp_id_md {
+	int ifindex;
+	__u32 flags;
+	struct xdp_link_info info;
+	__u64 feature_flags;
+};
+
+struct xdp_features_md {
+	int ifindex;
+	__u32 xdp_zc_max_segs;
+	__u64 flags;
+};
+
+static int libbpf_netlink_open(__u32 *nl_pid, int proto)
+{
+	struct sockaddr_nl sa;
+	socklen_t addrlen;
+	int one = 1, ret;
+	int sock;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+
+	sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, proto);
+	if (sock < 0)
+		return -errno;
+
+	if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
+		       &one, sizeof(one)) < 0) {
+		pr_warn("Netlink error reporting not supported\n");
+	}
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	addrlen = sizeof(sa);
+	if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
+		ret = -errno;
+		goto cleanup;
+	}
+
+	if (addrlen != sizeof(sa)) {
+		ret = -LIBBPF_ERRNO__INTERNAL;
+		goto cleanup;
+	}
+
+	*nl_pid = sa.nl_pid;
+	return sock;
+
+cleanup:
+	close(sock);
+	return ret;
+}
+
+static void libbpf_netlink_close(int sock)
+{
+	close(sock);
+}
+
+enum {
+	NL_CONT,
+	NL_NEXT,
+	NL_DONE,
+};
+
+static int netlink_recvmsg(int sock, struct msghdr *mhdr, int flags)
+{
+	int len;
+
+	do {
+		len = recvmsg(sock, mhdr, flags);
+	} while (len < 0 && (errno == EINTR || errno == EAGAIN));
+
+	if (len < 0)
+		return -errno;
+	return len;
+}
+
+static int alloc_iov(struct iovec *iov, int len)
+{
+	void *nbuf;
+
+	nbuf = realloc(iov->iov_base, len);
+	if (!nbuf)
+		return -ENOMEM;
+
+	iov->iov_base = nbuf;
+	iov->iov_len = len;
+	return 0;
+}
+
+static int libbpf_netlink_recv(int sock, __u32 nl_pid, int seq,
+			       __dump_nlmsg_t _fn, libbpf_dump_nlmsg_t fn,
+			       void *cookie)
+{
+	struct iovec iov = {};
+	struct msghdr mhdr = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+	};
+	bool multipart = true;
+	struct nlmsgerr *err;
+	struct nlmsghdr *nh;
+	int len, ret;
+
+	ret = alloc_iov(&iov, 8192);
+	if (ret)
+		goto done;
+
+	while (multipart) {
+start:
+		multipart = false;
+		len = netlink_recvmsg(sock, &mhdr, MSG_PEEK | MSG_TRUNC);
+		if (len < 0) {
+			ret = len;
+			goto done;
+		}
+
+		if (len > iov.iov_len) {
+			ret = alloc_iov(&iov, len);
+			if (ret)
+				goto done;
+		}
+
+		len = netlink_recvmsg(sock, &mhdr, 0);
+		if (len < 0) {
+			ret = len;
+			goto done;
+		}
+
+		if (len == 0)
+			break;
+
+		for (nh = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(nh, len);
+		     nh = NLMSG_NEXT(nh, len)) {
+			if (nh->nlmsg_pid != nl_pid) {
+				ret = -LIBBPF_ERRNO__WRNGPID;
+				goto done;
+			}
+			if (nh->nlmsg_seq != seq) {
+				ret = -LIBBPF_ERRNO__INVSEQ;
+				goto done;
+			}
+			if (nh->nlmsg_flags & NLM_F_MULTI)
+				multipart = true;
+			switch (nh->nlmsg_type) {
+			case NLMSG_ERROR:
+				err = (struct nlmsgerr *)NLMSG_DATA(nh);
+				if (!err->error)
+					continue;
+				ret = err->error;
+				libbpf_nla_dump_errormsg(nh);
+				goto done;
+			case NLMSG_DONE:
+				ret = 0;
+				goto done;
+			default:
+				break;
+			}
+			if (_fn) {
+				ret = _fn(nh, fn, cookie);
+				switch (ret) {
+				case NL_CONT:
+					break;
+				case NL_NEXT:
+					goto start;
+				case NL_DONE:
+					ret = 0;
+					goto done;
+				default:
+					goto done;
+				}
+			}
+		}
+		if (len)
+			pr_warn("Invalid message or trailing data in Netlink response: %d bytes left\n", len);
+	}
+	ret = 0;
+done:
+	free(iov.iov_base);
+	return ret;
+}
+
+static int libbpf_netlink_send_recv(struct libbpf_nla_req *req,
+				    int proto, __dump_nlmsg_t parse_msg,
+				    libbpf_dump_nlmsg_t parse_attr,
+				    void *cookie)
+{
+	__u32 nl_pid = 0;
+	int sock, ret;
+
+	sock = libbpf_netlink_open(&nl_pid, proto);
+	if (sock < 0)
+		return sock;
+
+	req->nh.nlmsg_pid = 0;
+	req->nh.nlmsg_seq = time(NULL);
+
+	if (send(sock, req, req->nh.nlmsg_len, 0) < 0) {
+		ret = -errno;
+		goto out;
+	}
+
+	ret = libbpf_netlink_recv(sock, nl_pid, req->nh.nlmsg_seq,
+				  parse_msg, parse_attr, cookie);
+out:
+	libbpf_netlink_close(sock);
+	return ret;
+}
+
+static int parse_genl_family_id(struct nlmsghdr *nh, libbpf_dump_nlmsg_t fn,
+				void *cookie)
+{
+	struct genlmsghdr *gnl = NLMSG_DATA(nh);
+	struct nlattr *na = (struct nlattr *)((void *)gnl + GENL_HDRLEN);
+	struct nlattr *tb[CTRL_ATTR_FAMILY_ID + 1];
+	__u16 *id = cookie;
+
+	libbpf_nla_parse(tb, CTRL_ATTR_FAMILY_ID, na,
+			 NLMSG_PAYLOAD(nh, sizeof(*gnl)), NULL);
+	if (!tb[CTRL_ATTR_FAMILY_ID])
+		return NL_CONT;
+
+	*id = libbpf_nla_getattr_u16(tb[CTRL_ATTR_FAMILY_ID]);
+	return NL_DONE;
+}
+
+static int libbpf_netlink_resolve_genl_family_id(const char *name,
+						 __u16 len, __u16 *id)
+{
+	struct libbpf_nla_req req = {
+		.nh.nlmsg_len	= NLMSG_LENGTH(GENL_HDRLEN),
+		.nh.nlmsg_type	= GENL_ID_CTRL,
+		.nh.nlmsg_flags	= NLM_F_REQUEST,
+		.gnl.cmd	= CTRL_CMD_GETFAMILY,
+		.gnl.version	= 2,
+	};
+	int err;
+
+	err = nlattr_add(&req, CTRL_ATTR_FAMILY_NAME, name, len);
+	if (err < 0)
+		return err;
+
+	return libbpf_netlink_send_recv(&req, NETLINK_GENERIC,
+					parse_genl_family_id, NULL, id);
+}
+
+static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd,
+					 __u32 flags)
+{
+	struct nlattr *nla;
+	int ret;
+	struct libbpf_nla_req req;
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len      = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+	req.nh.nlmsg_flags    = NLM_F_REQUEST | NLM_F_ACK;
+	req.nh.nlmsg_type     = RTM_SETLINK;
+	req.ifinfo.ifi_family = AF_UNSPEC;
+	req.ifinfo.ifi_index  = ifindex;
+
+	nla = nlattr_begin_nested(&req, IFLA_XDP);
+	if (!nla)
+		return -EMSGSIZE;
+	ret = nlattr_add(&req, IFLA_XDP_FD, &fd, sizeof(fd));
+	if (ret < 0)
+		return ret;
+	if (flags) {
+		ret = nlattr_add(&req, IFLA_XDP_FLAGS, &flags, sizeof(flags));
+		if (ret < 0)
+			return ret;
+	}
+	if (flags & XDP_FLAGS_REPLACE) {
+		ret = nlattr_add(&req, IFLA_XDP_EXPECTED_FD, &old_fd,
+				 sizeof(old_fd));
+		if (ret < 0)
+			return ret;
+	}
+	nlattr_end_nested(&req, nla);
+
+	return libbpf_netlink_send_recv(&req, NETLINK_ROUTE, NULL, NULL, NULL);
+}
+
+int bpf_xdp_attach(int ifindex, int prog_fd, __u32 flags, const struct bpf_xdp_attach_opts *opts)
+{
+	int old_prog_fd, err;
+
+	if (!OPTS_VALID(opts, bpf_xdp_attach_opts))
+		return libbpf_err(-EINVAL);
+
+	old_prog_fd = OPTS_GET(opts, old_prog_fd, 0);
+	if (old_prog_fd)
+		flags |= XDP_FLAGS_REPLACE;
+	else
+		old_prog_fd = -1;
+
+	err = __bpf_set_link_xdp_fd_replace(ifindex, prog_fd, old_prog_fd, flags);
+	return libbpf_err(err);
+}
+
+int bpf_xdp_detach(int ifindex, __u32 flags, const struct bpf_xdp_attach_opts *opts)
+{
+	return bpf_xdp_attach(ifindex, -1, flags, opts);
+}
+
+static int __dump_link_nlmsg(struct nlmsghdr *nlh,
+			     libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
+{
+	struct nlattr *tb[IFLA_MAX + 1], *attr;
+	struct ifinfomsg *ifi = NLMSG_DATA(nlh);
+	int len;
+
+	len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
+	attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
+
+	if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
+		return -LIBBPF_ERRNO__NLPARSE;
+
+	return dump_link_nlmsg(cookie, ifi, tb);
+}
+
+static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb)
+{
+	struct nlattr *xdp_tb[IFLA_XDP_MAX + 1];
+	struct xdp_id_md *xdp_id = cookie;
+	struct ifinfomsg *ifinfo = msg;
+	int ret;
+
+	if (xdp_id->ifindex && xdp_id->ifindex != ifinfo->ifi_index)
+		return 0;
+
+	if (!tb[IFLA_XDP])
+		return 0;
+
+	ret = libbpf_nla_parse_nested(xdp_tb, IFLA_XDP_MAX, tb[IFLA_XDP], NULL);
+	if (ret)
+		return ret;
+
+	if (!xdp_tb[IFLA_XDP_ATTACHED])
+		return 0;
+
+	xdp_id->info.attach_mode = libbpf_nla_getattr_u8(
+		xdp_tb[IFLA_XDP_ATTACHED]);
+
+	if (xdp_id->info.attach_mode == XDP_ATTACHED_NONE)
+		return 0;
+
+	if (xdp_tb[IFLA_XDP_PROG_ID])
+		xdp_id->info.prog_id = libbpf_nla_getattr_u32(
+			xdp_tb[IFLA_XDP_PROG_ID]);
+
+	if (xdp_tb[IFLA_XDP_SKB_PROG_ID])
+		xdp_id->info.skb_prog_id = libbpf_nla_getattr_u32(
+			xdp_tb[IFLA_XDP_SKB_PROG_ID]);
+
+	if (xdp_tb[IFLA_XDP_DRV_PROG_ID])
+		xdp_id->info.drv_prog_id = libbpf_nla_getattr_u32(
+			xdp_tb[IFLA_XDP_DRV_PROG_ID]);
+
+	if (xdp_tb[IFLA_XDP_HW_PROG_ID])
+		xdp_id->info.hw_prog_id = libbpf_nla_getattr_u32(
+			xdp_tb[IFLA_XDP_HW_PROG_ID]);
+
+	return 0;
+}
+
+static int parse_xdp_features(struct nlmsghdr *nh, libbpf_dump_nlmsg_t fn,
+			      void *cookie)
+{
+	struct genlmsghdr *gnl = NLMSG_DATA(nh);
+	struct nlattr *na = (struct nlattr *)((void *)gnl + GENL_HDRLEN);
+	struct nlattr *tb[NETDEV_CMD_MAX + 1];
+	struct xdp_features_md *md = cookie;
+	__u32 ifindex;
+
+	libbpf_nla_parse(tb, NETDEV_CMD_MAX, na,
+			 NLMSG_PAYLOAD(nh, sizeof(*gnl)), NULL);
+
+	if (!tb[NETDEV_A_DEV_IFINDEX] || !tb[NETDEV_A_DEV_XDP_FEATURES])
+		return NL_CONT;
+
+	ifindex = libbpf_nla_getattr_u32(tb[NETDEV_A_DEV_IFINDEX]);
+	if (ifindex != md->ifindex)
+		return NL_CONT;
+
+	md->flags = libbpf_nla_getattr_u64(tb[NETDEV_A_DEV_XDP_FEATURES]);
+	if (tb[NETDEV_A_DEV_XDP_ZC_MAX_SEGS])
+		md->xdp_zc_max_segs =
+			libbpf_nla_getattr_u32(tb[NETDEV_A_DEV_XDP_ZC_MAX_SEGS]);
+	return NL_DONE;
+}
+
+int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
+{
+	struct libbpf_nla_req req = {
+		.nh.nlmsg_len      = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+		.nh.nlmsg_type     = RTM_GETLINK,
+		.nh.nlmsg_flags    = NLM_F_DUMP | NLM_F_REQUEST,
+		.ifinfo.ifi_family = AF_PACKET,
+	};
+	struct xdp_id_md xdp_id = {};
+	struct xdp_features_md md = {
+		.ifindex = ifindex,
+	};
+	__u16 id;
+	int err;
+
+	if (!OPTS_VALID(opts, bpf_xdp_query_opts))
+		return libbpf_err(-EINVAL);
+
+	if (xdp_flags & ~XDP_FLAGS_MASK)
+		return libbpf_err(-EINVAL);
+
+	/* Check whether the single {HW,DRV,SKB} mode is set */
+	xdp_flags &= XDP_FLAGS_SKB_MODE | XDP_FLAGS_DRV_MODE | XDP_FLAGS_HW_MODE;
+	if (xdp_flags & (xdp_flags - 1))
+		return libbpf_err(-EINVAL);
+
+	xdp_id.ifindex = ifindex;
+	xdp_id.flags = xdp_flags;
+
+	err = libbpf_netlink_send_recv(&req, NETLINK_ROUTE, __dump_link_nlmsg,
+				       get_xdp_info, &xdp_id);
+	if (err)
+		return libbpf_err(err);
+
+	OPTS_SET(opts, prog_id, xdp_id.info.prog_id);
+	OPTS_SET(opts, drv_prog_id, xdp_id.info.drv_prog_id);
+	OPTS_SET(opts, hw_prog_id, xdp_id.info.hw_prog_id);
+	OPTS_SET(opts, skb_prog_id, xdp_id.info.skb_prog_id);
+	OPTS_SET(opts, attach_mode, xdp_id.info.attach_mode);
+
+	if (!OPTS_HAS(opts, feature_flags))
+		return 0;
+
+	err = libbpf_netlink_resolve_genl_family_id("netdev", sizeof("netdev"), &id);
+	if (err < 0) {
+		if (err == -ENOENT) {
+			opts->feature_flags = 0;
+			goto skip_feature_flags;
+		}
+		return libbpf_err(err);
+	}
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
+	req.nh.nlmsg_flags = NLM_F_REQUEST;
+	req.nh.nlmsg_type = id;
+	req.gnl.cmd = NETDEV_CMD_DEV_GET;
+	req.gnl.version = 2;
+
+	err = nlattr_add(&req, NETDEV_A_DEV_IFINDEX, &ifindex, sizeof(ifindex));
+	if (err < 0)
+		return libbpf_err(err);
+
+	err = libbpf_netlink_send_recv(&req, NETLINK_GENERIC,
+				       parse_xdp_features, NULL, &md);
+	if (err)
+		return libbpf_err(err);
+
+	OPTS_SET(opts, feature_flags, md.flags);
+	OPTS_SET(opts, xdp_zc_max_segs, md.xdp_zc_max_segs);
+
+skip_feature_flags:
+	return 0;
+}
+
+int bpf_xdp_query_id(int ifindex, int flags, __u32 *prog_id)
+{
+	LIBBPF_OPTS(bpf_xdp_query_opts, opts);
+	int ret;
+
+	ret = bpf_xdp_query(ifindex, flags, &opts);
+	if (ret)
+		return libbpf_err(ret);
+
+	flags &= XDP_FLAGS_MODES;
+
+	if (opts.attach_mode != XDP_ATTACHED_MULTI && !flags)
+		*prog_id = opts.prog_id;
+	else if (flags & XDP_FLAGS_DRV_MODE)
+		*prog_id = opts.drv_prog_id;
+	else if (flags & XDP_FLAGS_HW_MODE)
+		*prog_id = opts.hw_prog_id;
+	else if (flags & XDP_FLAGS_SKB_MODE)
+		*prog_id = opts.skb_prog_id;
+	else
+		*prog_id = 0;
+
+	return 0;
+}
+
+
+typedef int (*qdisc_config_t)(struct libbpf_nla_req *req, const struct bpf_tc_hook *hook);
+
+static int clsact_config(struct libbpf_nla_req *req, const struct bpf_tc_hook *hook)
+{
+	req->tc.tcm_parent = TC_H_CLSACT;
+	req->tc.tcm_handle = TC_H_MAKE(TC_H_CLSACT, 0);
+
+	return nlattr_add(req, TCA_KIND, "clsact", sizeof("clsact"));
+}
+
+static int qdisc_config(struct libbpf_nla_req *req, const struct bpf_tc_hook *hook)
+{
+	const char *qdisc = OPTS_GET(hook, qdisc, NULL);
+
+	req->tc.tcm_parent = OPTS_GET(hook, parent, TC_H_ROOT);
+	req->tc.tcm_handle = OPTS_GET(hook, handle, 0);
+
+	return nlattr_add(req, TCA_KIND, qdisc, strlen(qdisc) + 1);
+}
+
+static int attach_point_to_config(struct bpf_tc_hook *hook,
+				  qdisc_config_t *config)
+{
+	switch (OPTS_GET(hook, attach_point, 0)) {
+	case BPF_TC_INGRESS:
+	case BPF_TC_EGRESS:
+	case BPF_TC_INGRESS | BPF_TC_EGRESS:
+		if (OPTS_GET(hook, parent, 0))
+			return -EINVAL;
+		*config = &clsact_config;
+		return 0;
+	case BPF_TC_CUSTOM:
+		return -EOPNOTSUPP;
+	case BPF_TC_QDISC:
+		*config = &qdisc_config;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int tc_get_tcm_parent(enum bpf_tc_attach_point attach_point,
+			     __u32 *parent)
+{
+	switch (attach_point) {
+	case BPF_TC_INGRESS:
+	case BPF_TC_EGRESS:
+		if (*parent)
+			return -EINVAL;
+		*parent = TC_H_MAKE(TC_H_CLSACT,
+				    attach_point == BPF_TC_INGRESS ?
+				    TC_H_MIN_INGRESS : TC_H_MIN_EGRESS);
+		break;
+	case BPF_TC_CUSTOM:
+		if (!*parent)
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int tc_qdisc_modify(struct bpf_tc_hook *hook, int cmd, int flags)
+{
+	qdisc_config_t config;
+	int ret;
+	struct libbpf_nla_req req;
+
+	ret = attach_point_to_config(hook, &config);
+	if (ret < 0)
+		return ret;
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len   = NLMSG_LENGTH(sizeof(struct tcmsg));
+	req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
+	req.nh.nlmsg_type  = cmd;
+	req.tc.tcm_family  = AF_UNSPEC;
+	req.tc.tcm_ifindex = OPTS_GET(hook, ifindex, 0);
+
+	ret = config(&req, hook);
+	if (ret < 0)
+		return ret;
+
+	return libbpf_netlink_send_recv(&req, NETLINK_ROUTE, NULL, NULL, NULL);
+}
+
+static int tc_qdisc_create_excl(struct bpf_tc_hook *hook)
+{
+	return tc_qdisc_modify(hook, RTM_NEWQDISC, NLM_F_CREATE | NLM_F_EXCL);
+}
+
+static int tc_qdisc_delete(struct bpf_tc_hook *hook)
+{
+	return tc_qdisc_modify(hook, RTM_DELQDISC, 0);
+}
+
+int bpf_tc_hook_create(struct bpf_tc_hook *hook)
+{
+	int ret;
+
+	if (!hook || !OPTS_VALID(hook, bpf_tc_hook) ||
+	    OPTS_GET(hook, ifindex, 0) <= 0)
+		return libbpf_err(-EINVAL);
+
+	ret = tc_qdisc_create_excl(hook);
+	return libbpf_err(ret);
+}
+
+static int __bpf_tc_detach(const struct bpf_tc_hook *hook,
+			   const struct bpf_tc_opts *opts,
+			   const bool flush);
+
+int bpf_tc_hook_destroy(struct bpf_tc_hook *hook)
+{
+	if (!hook || !OPTS_VALID(hook, bpf_tc_hook) ||
+	    OPTS_GET(hook, ifindex, 0) <= 0)
+		return libbpf_err(-EINVAL);
+
+	switch (OPTS_GET(hook, attach_point, 0)) {
+	case BPF_TC_INGRESS:
+	case BPF_TC_EGRESS:
+		return libbpf_err(__bpf_tc_detach(hook, NULL, true));
+	case BPF_TC_QDISC:
+	case BPF_TC_INGRESS | BPF_TC_EGRESS:
+		return libbpf_err(tc_qdisc_delete(hook));
+	case BPF_TC_CUSTOM:
+		return libbpf_err(-EOPNOTSUPP);
+	default:
+		return libbpf_err(-EINVAL);
+	}
+}
+
+struct bpf_cb_ctx {
+	struct bpf_tc_opts *opts;
+	bool processed;
+};
+
+static int __get_tc_info(void *cookie, struct tcmsg *tc, struct nlattr **tb,
+			 bool unicast)
+{
+	struct nlattr *tbb[TCA_BPF_MAX + 1];
+	struct bpf_cb_ctx *info = cookie;
+
+	if (!info || !info->opts)
+		return -EINVAL;
+	if (unicast && info->processed)
+		return -EINVAL;
+	if (!tb[TCA_OPTIONS])
+		return NL_CONT;
+
+	libbpf_nla_parse_nested(tbb, TCA_BPF_MAX, tb[TCA_OPTIONS], NULL);
+	if (!tbb[TCA_BPF_ID])
+		return -EINVAL;
+
+	OPTS_SET(info->opts, prog_id, libbpf_nla_getattr_u32(tbb[TCA_BPF_ID]));
+	OPTS_SET(info->opts, handle, tc->tcm_handle);
+	OPTS_SET(info->opts, priority, TC_H_MAJ(tc->tcm_info) >> 16);
+
+	info->processed = true;
+	return unicast ? NL_NEXT : NL_DONE;
+}
+
+static int get_tc_info(struct nlmsghdr *nh, libbpf_dump_nlmsg_t fn,
+		       void *cookie)
+{
+	struct tcmsg *tc = NLMSG_DATA(nh);
+	struct nlattr *tb[TCA_MAX + 1];
+
+	libbpf_nla_parse(tb, TCA_MAX,
+			 (struct nlattr *)((void *)tc + NLMSG_ALIGN(sizeof(*tc))),
+			 NLMSG_PAYLOAD(nh, sizeof(*tc)), NULL);
+	if (!tb[TCA_KIND])
+		return NL_CONT;
+	return __get_tc_info(cookie, tc, tb, nh->nlmsg_flags & NLM_F_ECHO);
+}
+
+static int tc_add_fd_and_name(struct libbpf_nla_req *req, int fd)
+{
+	struct bpf_prog_info info;
+	__u32 info_len = sizeof(info);
+	char name[256];
+	int len, ret;
+
+	memset(&info, 0, info_len);
+	ret = bpf_prog_get_info_by_fd(fd, &info, &info_len);
+	if (ret < 0)
+		return ret;
+
+	ret = nlattr_add(req, TCA_BPF_FD, &fd, sizeof(fd));
+	if (ret < 0)
+		return ret;
+	len = snprintf(name, sizeof(name), "%s:[%u]", info.name, info.id);
+	if (len < 0)
+		return -errno;
+	if (len >= sizeof(name))
+		return -ENAMETOOLONG;
+	return nlattr_add(req, TCA_BPF_NAME, name, len + 1);
+}
+
+int bpf_tc_attach(const struct bpf_tc_hook *hook, struct bpf_tc_opts *opts)
+{
+	__u32 protocol, bpf_flags, handle, priority, parent, prog_id, flags;
+	int ret, ifindex, attach_point, prog_fd;
+	struct bpf_cb_ctx info = {};
+	struct libbpf_nla_req req;
+	struct nlattr *nla;
+
+	if (!hook || !opts ||
+	    !OPTS_VALID(hook, bpf_tc_hook) ||
+	    !OPTS_VALID(opts, bpf_tc_opts))
+		return libbpf_err(-EINVAL);
+
+	ifindex      = OPTS_GET(hook, ifindex, 0);
+	parent       = OPTS_GET(hook, parent, 0);
+	attach_point = OPTS_GET(hook, attach_point, 0);
+
+	handle       = OPTS_GET(opts, handle, 0);
+	priority     = OPTS_GET(opts, priority, 0);
+	prog_fd      = OPTS_GET(opts, prog_fd, 0);
+	prog_id      = OPTS_GET(opts, prog_id, 0);
+	flags        = OPTS_GET(opts, flags, 0);
+
+	if (ifindex <= 0 || !prog_fd || prog_id)
+		return libbpf_err(-EINVAL);
+	if (priority > UINT16_MAX)
+		return libbpf_err(-EINVAL);
+	if (flags & ~BPF_TC_F_REPLACE)
+		return libbpf_err(-EINVAL);
+
+	flags = (flags & BPF_TC_F_REPLACE) ? NLM_F_REPLACE : NLM_F_EXCL;
+	protocol = ETH_P_ALL;
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len   = NLMSG_LENGTH(sizeof(struct tcmsg));
+	req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE |
+			     NLM_F_ECHO | flags;
+	req.nh.nlmsg_type  = RTM_NEWTFILTER;
+	req.tc.tcm_family  = AF_UNSPEC;
+	req.tc.tcm_ifindex = ifindex;
+	req.tc.tcm_handle  = handle;
+	req.tc.tcm_info    = TC_H_MAKE(priority << 16, htons(protocol));
+
+	ret = tc_get_tcm_parent(attach_point, &parent);
+	if (ret < 0)
+		return libbpf_err(ret);
+	req.tc.tcm_parent = parent;
+
+	ret = nlattr_add(&req, TCA_KIND, "bpf", sizeof("bpf"));
+	if (ret < 0)
+		return libbpf_err(ret);
+	nla = nlattr_begin_nested(&req, TCA_OPTIONS);
+	if (!nla)
+		return libbpf_err(-EMSGSIZE);
+	ret = tc_add_fd_and_name(&req, prog_fd);
+	if (ret < 0)
+		return libbpf_err(ret);
+	bpf_flags = TCA_BPF_FLAG_ACT_DIRECT;
+	ret = nlattr_add(&req, TCA_BPF_FLAGS, &bpf_flags, sizeof(bpf_flags));
+	if (ret < 0)
+		return libbpf_err(ret);
+	nlattr_end_nested(&req, nla);
+
+	info.opts = opts;
+
+	ret = libbpf_netlink_send_recv(&req, NETLINK_ROUTE, get_tc_info, NULL,
+				       &info);
+	if (ret < 0)
+		return libbpf_err(ret);
+	if (!info.processed)
+		return libbpf_err(-ENOENT);
+	return ret;
+}
+
+static int __bpf_tc_detach(const struct bpf_tc_hook *hook,
+			   const struct bpf_tc_opts *opts,
+			   const bool flush)
+{
+	__u32 protocol = 0, handle, priority, parent, prog_id, flags;
+	int ret, ifindex, attach_point, prog_fd;
+	struct libbpf_nla_req req;
+
+	if (!hook ||
+	    !OPTS_VALID(hook, bpf_tc_hook) ||
+	    !OPTS_VALID(opts, bpf_tc_opts))
+		return -EINVAL;
+
+	ifindex      = OPTS_GET(hook, ifindex, 0);
+	parent       = OPTS_GET(hook, parent, 0);
+	attach_point = OPTS_GET(hook, attach_point, 0);
+
+	handle       = OPTS_GET(opts, handle, 0);
+	priority     = OPTS_GET(opts, priority, 0);
+	prog_fd      = OPTS_GET(opts, prog_fd, 0);
+	prog_id      = OPTS_GET(opts, prog_id, 0);
+	flags        = OPTS_GET(opts, flags, 0);
+
+	if (ifindex <= 0 || flags || prog_fd || prog_id)
+		return -EINVAL;
+	if (priority > UINT16_MAX)
+		return -EINVAL;
+	if (!flush) {
+		if (!handle || !priority)
+			return -EINVAL;
+		protocol = ETH_P_ALL;
+	} else {
+		if (handle || priority)
+			return -EINVAL;
+	}
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len   = NLMSG_LENGTH(sizeof(struct tcmsg));
+	req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	req.nh.nlmsg_type  = RTM_DELTFILTER;
+	req.tc.tcm_family  = AF_UNSPEC;
+	req.tc.tcm_ifindex = ifindex;
+	if (!flush) {
+		req.tc.tcm_handle = handle;
+		req.tc.tcm_info   = TC_H_MAKE(priority << 16, htons(protocol));
+	}
+
+	ret = tc_get_tcm_parent(attach_point, &parent);
+	if (ret < 0)
+		return ret;
+	req.tc.tcm_parent = parent;
+
+	if (!flush) {
+		ret = nlattr_add(&req, TCA_KIND, "bpf", sizeof("bpf"));
+		if (ret < 0)
+			return ret;
+	}
+
+	return libbpf_netlink_send_recv(&req, NETLINK_ROUTE, NULL, NULL, NULL);
+}
+
+int bpf_tc_detach(const struct bpf_tc_hook *hook,
+		  const struct bpf_tc_opts *opts)
+{
+	int ret;
+
+	if (!opts)
+		return libbpf_err(-EINVAL);
+
+	ret = __bpf_tc_detach(hook, opts, false);
+	return libbpf_err(ret);
+}
+
+int bpf_tc_query(const struct bpf_tc_hook *hook, struct bpf_tc_opts *opts)
+{
+	__u32 protocol, handle, priority, parent, prog_id, flags;
+	int ret, ifindex, attach_point, prog_fd;
+	struct bpf_cb_ctx info = {};
+	struct libbpf_nla_req req;
+
+	if (!hook || !opts ||
+	    !OPTS_VALID(hook, bpf_tc_hook) ||
+	    !OPTS_VALID(opts, bpf_tc_opts))
+		return libbpf_err(-EINVAL);
+
+	ifindex      = OPTS_GET(hook, ifindex, 0);
+	parent       = OPTS_GET(hook, parent, 0);
+	attach_point = OPTS_GET(hook, attach_point, 0);
+
+	handle       = OPTS_GET(opts, handle, 0);
+	priority     = OPTS_GET(opts, priority, 0);
+	prog_fd      = OPTS_GET(opts, prog_fd, 0);
+	prog_id      = OPTS_GET(opts, prog_id, 0);
+	flags        = OPTS_GET(opts, flags, 0);
+
+	if (ifindex <= 0 || flags || prog_fd || prog_id ||
+	    !handle || !priority)
+		return libbpf_err(-EINVAL);
+	if (priority > UINT16_MAX)
+		return libbpf_err(-EINVAL);
+
+	protocol = ETH_P_ALL;
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len   = NLMSG_LENGTH(sizeof(struct tcmsg));
+	req.nh.nlmsg_flags = NLM_F_REQUEST;
+	req.nh.nlmsg_type  = RTM_GETTFILTER;
+	req.tc.tcm_family  = AF_UNSPEC;
+	req.tc.tcm_ifindex = ifindex;
+	req.tc.tcm_handle  = handle;
+	req.tc.tcm_info    = TC_H_MAKE(priority << 16, htons(protocol));
+
+	ret = tc_get_tcm_parent(attach_point, &parent);
+	if (ret < 0)
+		return libbpf_err(ret);
+	req.tc.tcm_parent = parent;
+
+	ret = nlattr_add(&req, TCA_KIND, "bpf", sizeof("bpf"));
+	if (ret < 0)
+		return libbpf_err(ret);
+
+	info.opts = opts;
+
+	ret = libbpf_netlink_send_recv(&req, NETLINK_ROUTE, get_tc_info, NULL,
+				       &info);
+	if (ret < 0)
+		return libbpf_err(ret);
+	if (!info.processed)
+		return libbpf_err(-ENOENT);
+	return ret;
+}
diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c
new file mode 100644
index 000000000..007fe17d1
--- /dev/null
+++ b/tools/lib/bpf/nlattr.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+/*
+ * NETLINK      Netlink attributes
+ *
+ * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <linux/rtnetlink.h>
+#include "nlattr.h"
+#include "libbpf_internal.h"
+
+static uint16_t nla_attr_minlen[LIBBPF_NLA_TYPE_MAX+1] = {
+	[LIBBPF_NLA_U8]		= sizeof(uint8_t),
+	[LIBBPF_NLA_U16]	= sizeof(uint16_t),
+	[LIBBPF_NLA_U32]	= sizeof(uint32_t),
+	[LIBBPF_NLA_U64]	= sizeof(uint64_t),
+	[LIBBPF_NLA_STRING]	= 1,
+	[LIBBPF_NLA_FLAG]	= 0,
+};
+
+static struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
+{
+	int totlen = NLA_ALIGN(nla->nla_len);
+
+	*remaining -= totlen;
+	return (struct nlattr *)((void *)nla + totlen);
+}
+
+static int nla_ok(const struct nlattr *nla, int remaining)
+{
+	return remaining >= (int)sizeof(*nla) &&
+	       nla->nla_len >= sizeof(*nla) &&
+	       nla->nla_len <= remaining;
+}
+
+static int nla_type(const struct nlattr *nla)
+{
+	return nla->nla_type & NLA_TYPE_MASK;
+}
+
+static int validate_nla(struct nlattr *nla, int maxtype,
+			struct libbpf_nla_policy *policy)
+{
+	struct libbpf_nla_policy *pt;
+	unsigned int minlen = 0;
+	int type = nla_type(nla);
+
+	if (type < 0 || type > maxtype)
+		return 0;
+
+	pt = &policy[type];
+
+	if (pt->type > LIBBPF_NLA_TYPE_MAX)
+		return 0;
+
+	if (pt->minlen)
+		minlen = pt->minlen;
+	else if (pt->type != LIBBPF_NLA_UNSPEC)
+		minlen = nla_attr_minlen[pt->type];
+
+	if (libbpf_nla_len(nla) < minlen)
+		return -EINVAL;
+
+	if (pt->maxlen && libbpf_nla_len(nla) > pt->maxlen)
+		return -EINVAL;
+
+	if (pt->type == LIBBPF_NLA_STRING) {
+		char *data = libbpf_nla_data(nla);
+
+		if (data[libbpf_nla_len(nla) - 1] != '\0')
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline int nlmsg_len(const struct nlmsghdr *nlh)
+{
+	return nlh->nlmsg_len - NLMSG_HDRLEN;
+}
+
+/**
+ * Create attribute index based on a stream of attributes.
+ * @arg tb		Index array to be filled (maxtype+1 elements).
+ * @arg maxtype		Maximum attribute type expected and accepted.
+ * @arg head		Head of attribute stream.
+ * @arg len		Length of attribute stream.
+ * @arg policy		Attribute validation policy.
+ *
+ * Iterates over the stream of attributes and stores a pointer to each
+ * attribute in the index array using the attribute type as index to
+ * the array. Attribute with a type greater than the maximum type
+ * specified will be silently ignored in order to maintain backwards
+ * compatibility. If \a policy is not NULL, the attribute will be
+ * validated using the specified policy.
+ *
+ * @see nla_validate
+ * @return 0 on success or a negative error code.
+ */
+int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,
+		     int len, struct libbpf_nla_policy *policy)
+{
+	struct nlattr *nla;
+	int rem, err;
+
+	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
+
+	libbpf_nla_for_each_attr(nla, head, len, rem) {
+		int type = nla_type(nla);
+
+		if (type > maxtype)
+			continue;
+
+		if (policy) {
+			err = validate_nla(nla, maxtype, policy);
+			if (err < 0)
+				return err;
+		}
+
+		if (tb[type]) {
+			pr_warn("Attribute of type %#x found multiple times in message, "
+				"previous attribute is being ignored.\n", (unsigned)type);
+		}
+
+		tb[type] = nla;
+	}
+
+	return 0;
+}
+
+/**
+ * Create attribute index based on nested attribute
+ * @arg tb              Index array to be filled (maxtype+1 elements).
+ * @arg maxtype         Maximum attribute type expected and accepted.
+ * @arg nla             Nested Attribute.
+ * @arg policy          Attribute validation policy.
+ *
+ * Feeds the stream of attributes nested into the specified attribute
+ * to libbpf_nla_parse().
+ *
+ * @see libbpf_nla_parse
+ * @return 0 on success or a negative error code.
+ */
+int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype,
+			    struct nlattr *nla,
+			    struct libbpf_nla_policy *policy)
+{
+	return libbpf_nla_parse(tb, maxtype, libbpf_nla_data(nla),
+				libbpf_nla_len(nla), policy);
+}
+
+/* dump netlink extended ack error message */
+int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh)
+{
+	struct libbpf_nla_policy extack_policy[NLMSGERR_ATTR_MAX + 1] = {
+		[NLMSGERR_ATTR_MSG]	= { .type = LIBBPF_NLA_STRING },
+		[NLMSGERR_ATTR_OFFS]	= { .type = LIBBPF_NLA_U32 },
+	};
+	struct nlattr *tb[NLMSGERR_ATTR_MAX + 1], *attr;
+	struct nlmsgerr *err;
+	char *errmsg = NULL;
+	int hlen, alen;
+
+	/* no TLVs, nothing to do here */
+	if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
+		return 0;
+
+	err = (struct nlmsgerr *)NLMSG_DATA(nlh);
+	hlen = sizeof(*err);
+
+	/* if NLM_F_CAPPED is set then the inner err msg was capped */
+	if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
+		hlen += nlmsg_len(&err->msg);
+
+	attr = (struct nlattr *) ((void *) err + hlen);
+	alen = (void *)nlh + nlh->nlmsg_len - (void *)attr;
+
+	if (libbpf_nla_parse(tb, NLMSGERR_ATTR_MAX, attr, alen,
+			     extack_policy) != 0) {
+		pr_warn("Failed to parse extended error attributes\n");
+		return 0;
+	}
+
+	if (tb[NLMSGERR_ATTR_MSG])
+		errmsg = (char *) libbpf_nla_data(tb[NLMSGERR_ATTR_MSG]);
+
+	pr_warn("Kernel error message: %s\n", errmsg);
+
+	return 0;
+}
diff --git a/tools/lib/bpf/nlattr.h b/tools/lib/bpf/nlattr.h
new file mode 100644
index 000000000..d92d1c1de
--- /dev/null
+++ b/tools/lib/bpf/nlattr.h
@@ -0,0 +1,176 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/*
+ * NETLINK      Netlink attributes
+ *
+ * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
+ */
+
+#ifndef __LIBBPF_NLATTR_H
+#define __LIBBPF_NLATTR_H
+
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/genetlink.h>
+
+/* avoid multiple definition of netlink features */
+#define __LINUX_NETLINK_H
+
+/**
+ * Standard attribute types to specify validation policy
+ */
+enum {
+	LIBBPF_NLA_UNSPEC,	/**< Unspecified type, binary data chunk */
+	LIBBPF_NLA_U8,		/**< 8 bit integer */
+	LIBBPF_NLA_U16,		/**< 16 bit integer */
+	LIBBPF_NLA_U32,		/**< 32 bit integer */
+	LIBBPF_NLA_U64,		/**< 64 bit integer */
+	LIBBPF_NLA_STRING,	/**< NUL terminated character string */
+	LIBBPF_NLA_FLAG,	/**< Flag */
+	LIBBPF_NLA_MSECS,	/**< Micro seconds (64bit) */
+	LIBBPF_NLA_NESTED,	/**< Nested attributes */
+	__LIBBPF_NLA_TYPE_MAX,
+};
+
+#define LIBBPF_NLA_TYPE_MAX (__LIBBPF_NLA_TYPE_MAX - 1)
+
+/**
+ * @ingroup attr
+ * Attribute validation policy.
+ *
+ * See section @core_doc{core_attr_parse,Attribute Parsing} for more details.
+ */
+struct libbpf_nla_policy {
+	/** Type of attribute or LIBBPF_NLA_UNSPEC */
+	uint16_t	type;
+
+	/** Minimal length of payload required */
+	uint16_t	minlen;
+
+	/** Maximal length of payload allowed */
+	uint16_t	maxlen;
+};
+
+struct libbpf_nla_req {
+	struct nlmsghdr nh;
+	union {
+		struct ifinfomsg ifinfo;
+		struct tcmsg tc;
+		struct genlmsghdr gnl;
+	};
+	char buf[128];
+};
+
+/**
+ * @ingroup attr
+ * Iterate over a stream of attributes
+ * @arg pos	loop counter, set to current attribute
+ * @arg head	head of attribute stream
+ * @arg len	length of attribute stream
+ * @arg rem	initialized to len, holds bytes currently remaining in stream
+ */
+#define libbpf_nla_for_each_attr(pos, head, len, rem) \
+	for (pos = head, rem = len; \
+	     nla_ok(pos, rem); \
+	     pos = nla_next(pos, &(rem)))
+
+/**
+ * libbpf_nla_data - head of payload
+ * @nla: netlink attribute
+ */
+static inline void *libbpf_nla_data(const struct nlattr *nla)
+{
+	return (void *)nla + NLA_HDRLEN;
+}
+
+static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla)
+{
+	return *(uint8_t *)libbpf_nla_data(nla);
+}
+
+static inline uint16_t libbpf_nla_getattr_u16(const struct nlattr *nla)
+{
+	return *(uint16_t *)libbpf_nla_data(nla);
+}
+
+static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla)
+{
+	return *(uint32_t *)libbpf_nla_data(nla);
+}
+
+static inline uint64_t libbpf_nla_getattr_u64(const struct nlattr *nla)
+{
+	return *(uint64_t *)libbpf_nla_data(nla);
+}
+
+static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla)
+{
+	return (const char *)libbpf_nla_data(nla);
+}
+
+/**
+ * libbpf_nla_len - length of payload
+ * @nla: netlink attribute
+ */
+static inline int libbpf_nla_len(const struct nlattr *nla)
+{
+	return nla->nla_len - NLA_HDRLEN;
+}
+
+int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,
+		     int len, struct libbpf_nla_policy *policy);
+int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype,
+			    struct nlattr *nla,
+			    struct libbpf_nla_policy *policy);
+
+int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh);
+
+static inline struct nlattr *nla_data(struct nlattr *nla)
+{
+	return (struct nlattr *)((void *)nla + NLA_HDRLEN);
+}
+
+static inline struct nlattr *req_tail(struct libbpf_nla_req *req)
+{
+	return (struct nlattr *)((void *)req + NLMSG_ALIGN(req->nh.nlmsg_len));
+}
+
+static inline int nlattr_add(struct libbpf_nla_req *req, int type,
+			     const void *data, int len)
+{
+	struct nlattr *nla;
+
+	if (NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(NLA_HDRLEN + len) > sizeof(*req))
+		return -EMSGSIZE;
+	if (!!data != !!len)
+		return -EINVAL;
+
+	nla = req_tail(req);
+	nla->nla_type = type;
+	nla->nla_len = NLA_HDRLEN + len;
+	if (data)
+		memcpy(nla_data(nla), data, len);
+	req->nh.nlmsg_len = NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(nla->nla_len);
+	return 0;
+}
+
+static inline struct nlattr *nlattr_begin_nested(struct libbpf_nla_req *req, int type)
+{
+	struct nlattr *tail;
+
+	tail = req_tail(req);
+	if (nlattr_add(req, type | NLA_F_NESTED, NULL, 0))
+		return NULL;
+	return tail;
+}
+
+static inline void nlattr_end_nested(struct libbpf_nla_req *req,
+				     struct nlattr *tail)
+{
+	tail->nla_len = (void *)req_tail(req) - (void *)tail;
+}
+
+#endif /* __LIBBPF_NLATTR_H */
diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
new file mode 100644
index 000000000..8ad271572
--- /dev/null
+++ b/tools/lib/bpf/relo_core.c
@@ -0,0 +1,1704 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2019 Facebook */
+
+#ifdef __KERNEL__
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/string.h>
+#include <linux/bpf_verifier.h>
+#include "relo_core.h"
+
+static const char *btf_kind_str(const struct btf_type *t)
+{
+	return btf_type_str(t);
+}
+
+static bool is_ldimm64_insn(struct bpf_insn *insn)
+{
+	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
+}
+
+static const struct btf_type *
+skip_mods_and_typedefs(const struct btf *btf, u32 id, u32 *res_id)
+{
+	return btf_type_skip_modifiers(btf, id, res_id);
+}
+
+static const char *btf__name_by_offset(const struct btf *btf, u32 offset)
+{
+	return btf_name_by_offset(btf, offset);
+}
+
+static s64 btf__resolve_size(const struct btf *btf, u32 type_id)
+{
+	const struct btf_type *t;
+	int size;
+
+	t = btf_type_by_id(btf, type_id);
+	t = btf_resolve_size(btf, t, &size);
+	if (IS_ERR(t))
+		return PTR_ERR(t);
+	return size;
+}
+
+enum libbpf_print_level {
+	LIBBPF_WARN,
+	LIBBPF_INFO,
+	LIBBPF_DEBUG,
+};
+
+#undef pr_warn
+#undef pr_info
+#undef pr_debug
+#define pr_warn(fmt, log, ...)	bpf_log((void *)log, fmt, "", ##__VA_ARGS__)
+#define pr_info(fmt, log, ...)	bpf_log((void *)log, fmt, "", ##__VA_ARGS__)
+#define pr_debug(fmt, log, ...)	bpf_log((void *)log, fmt, "", ##__VA_ARGS__)
+#define libbpf_print(level, fmt, ...)	bpf_log((void *)prog_name, fmt, ##__VA_ARGS__)
+#else
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <linux/err.h>
+
+#include "libbpf.h"
+#include "bpf.h"
+#include "btf.h"
+#include "libbpf_internal.h"
+#endif
+
+static bool is_flex_arr(const struct btf *btf,
+			const struct bpf_core_accessor *acc,
+			const struct btf_array *arr)
+{
+	const struct btf_type *t;
+
+	/* not a flexible array, if not inside a struct or has non-zero size */
+	if (!acc->name || arr->nelems > 0)
+		return false;
+
+	/* has to be the last member of enclosing struct */
+	t = btf_type_by_id(btf, acc->type_id);
+	return acc->idx == btf_vlen(t) - 1;
+}
+
+static const char *core_relo_kind_str(enum bpf_core_relo_kind kind)
+{
+	switch (kind) {
+	case BPF_CORE_FIELD_BYTE_OFFSET: return "byte_off";
+	case BPF_CORE_FIELD_BYTE_SIZE: return "byte_sz";
+	case BPF_CORE_FIELD_EXISTS: return "field_exists";
+	case BPF_CORE_FIELD_SIGNED: return "signed";
+	case BPF_CORE_FIELD_LSHIFT_U64: return "lshift_u64";
+	case BPF_CORE_FIELD_RSHIFT_U64: return "rshift_u64";
+	case BPF_CORE_TYPE_ID_LOCAL: return "local_type_id";
+	case BPF_CORE_TYPE_ID_TARGET: return "target_type_id";
+	case BPF_CORE_TYPE_EXISTS: return "type_exists";
+	case BPF_CORE_TYPE_MATCHES: return "type_matches";
+	case BPF_CORE_TYPE_SIZE: return "type_size";
+	case BPF_CORE_ENUMVAL_EXISTS: return "enumval_exists";
+	case BPF_CORE_ENUMVAL_VALUE: return "enumval_value";
+	default: return "unknown";
+	}
+}
+
+static bool core_relo_is_field_based(enum bpf_core_relo_kind kind)
+{
+	switch (kind) {
+	case BPF_CORE_FIELD_BYTE_OFFSET:
+	case BPF_CORE_FIELD_BYTE_SIZE:
+	case BPF_CORE_FIELD_EXISTS:
+	case BPF_CORE_FIELD_SIGNED:
+	case BPF_CORE_FIELD_LSHIFT_U64:
+	case BPF_CORE_FIELD_RSHIFT_U64:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool core_relo_is_type_based(enum bpf_core_relo_kind kind)
+{
+	switch (kind) {
+	case BPF_CORE_TYPE_ID_LOCAL:
+	case BPF_CORE_TYPE_ID_TARGET:
+	case BPF_CORE_TYPE_EXISTS:
+	case BPF_CORE_TYPE_MATCHES:
+	case BPF_CORE_TYPE_SIZE:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind)
+{
+	switch (kind) {
+	case BPF_CORE_ENUMVAL_EXISTS:
+	case BPF_CORE_ENUMVAL_VALUE:
+		return true;
+	default:
+		return false;
+	}
+}
+
+int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
+				const struct btf *targ_btf, __u32 targ_id, int level)
+{
+	const struct btf_type *local_type, *targ_type;
+	int depth = 32; /* max recursion depth */
+
+	/* caller made sure that names match (ignoring flavor suffix) */
+	local_type = btf_type_by_id(local_btf, local_id);
+	targ_type = btf_type_by_id(targ_btf, targ_id);
+	if (!btf_kind_core_compat(local_type, targ_type))
+		return 0;
+
+recur:
+	depth--;
+	if (depth < 0)
+		return -EINVAL;
+
+	local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
+	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
+	if (!local_type || !targ_type)
+		return -EINVAL;
+
+	if (!btf_kind_core_compat(local_type, targ_type))
+		return 0;
+
+	switch (btf_kind(local_type)) {
+	case BTF_KIND_UNKN:
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+	case BTF_KIND_ENUM:
+	case BTF_KIND_FWD:
+	case BTF_KIND_ENUM64:
+		return 1;
+	case BTF_KIND_INT:
+		/* just reject deprecated bitfield-like integers; all other
+		 * integers are by default compatible between each other
+		 */
+		return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0;
+	case BTF_KIND_PTR:
+		local_id = local_type->type;
+		targ_id = targ_type->type;
+		goto recur;
+	case BTF_KIND_ARRAY:
+		local_id = btf_array(local_type)->type;
+		targ_id = btf_array(targ_type)->type;
+		goto recur;
+	case BTF_KIND_FUNC_PROTO: {
+		struct btf_param *local_p = btf_params(local_type);
+		struct btf_param *targ_p = btf_params(targ_type);
+		__u32 local_vlen = btf_vlen(local_type);
+		__u32 targ_vlen = btf_vlen(targ_type);
+		int i, err;
+
+		if (local_vlen != targ_vlen)
+			return 0;
+
+		for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
+			if (level <= 0)
+				return -EINVAL;
+
+			skip_mods_and_typedefs(local_btf, local_p->type, &local_id);
+			skip_mods_and_typedefs(targ_btf, targ_p->type, &targ_id);
+			err = __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
+							  level - 1);
+			if (err <= 0)
+				return err;
+		}
+
+		/* tail recurse for return type check */
+		skip_mods_and_typedefs(local_btf, local_type->type, &local_id);
+		skip_mods_and_typedefs(targ_btf, targ_type->type, &targ_id);
+		goto recur;
+	}
+	default:
+		pr_warn("unexpected kind %s relocated, local [%u], target [%u]\n",
+			btf_kind_str(local_type), local_id, targ_id);
+		return 0;
+	}
+}
+
+/*
+ * Turn bpf_core_relo into a low- and high-level spec representation,
+ * validating correctness along the way, as well as calculating resulting
+ * field bit offset, specified by accessor string. Low-level spec captures
+ * every single level of nestedness, including traversing anonymous
+ * struct/union members. High-level one only captures semantically meaningful
+ * "turning points": named fields and array indicies.
+ * E.g., for this case:
+ *
+ *   struct sample {
+ *       int __unimportant;
+ *       struct {
+ *           int __1;
+ *           int __2;
+ *           int a[7];
+ *       };
+ *   };
+ *
+ *   struct sample *s = ...;
+ *
+ *   int x = &s->a[3]; // access string = '0:1:2:3'
+ *
+ * Low-level spec has 1:1 mapping with each element of access string (it's
+ * just a parsed access string representation): [0, 1, 2, 3].
+ *
+ * High-level spec will capture only 3 points:
+ *   - initial zero-index access by pointer (&s->... is the same as &s[0]...);
+ *   - field 'a' access (corresponds to '2' in low-level spec);
+ *   - array element #3 access (corresponds to '3' in low-level spec).
+ *
+ * Type-based relocations (TYPE_EXISTS/TYPE_MATCHES/TYPE_SIZE,
+ * TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their
+ * spec and raw_spec are kept empty.
+ *
+ * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access
+ * string to specify enumerator's value index that need to be relocated.
+ */
+int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
+			const struct bpf_core_relo *relo,
+			struct bpf_core_spec *spec)
+{
+	int access_idx, parsed_len, i;
+	struct bpf_core_accessor *acc;
+	const struct btf_type *t;
+	const char *name, *spec_str;
+	__u32 id, name_off;
+	__s64 sz;
+
+	spec_str = btf__name_by_offset(btf, relo->access_str_off);
+	if (str_is_empty(spec_str) || *spec_str == ':')
+		return -EINVAL;
+
+	memset(spec, 0, sizeof(*spec));
+	spec->btf = btf;
+	spec->root_type_id = relo->type_id;
+	spec->relo_kind = relo->kind;
+
+	/* type-based relocations don't have a field access string */
+	if (core_relo_is_type_based(relo->kind)) {
+		if (strcmp(spec_str, "0"))
+			return -EINVAL;
+		return 0;
+	}
+
+	/* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
+	while (*spec_str) {
+		if (*spec_str == ':')
+			++spec_str;
+		if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
+			return -EINVAL;
+		if (access_idx < 0)
+			return -EINVAL;
+		if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
+			return -E2BIG;
+		spec_str += parsed_len;
+		spec->raw_spec[spec->raw_len++] = access_idx;
+	}
+
+	if (spec->raw_len == 0)
+		return -EINVAL;
+
+	t = skip_mods_and_typedefs(btf, relo->type_id, &id);
+	if (!t)
+		return -EINVAL;
+
+	access_idx = spec->raw_spec[0];
+	acc = &spec->spec[0];
+	acc->type_id = id;
+	acc->idx = access_idx;
+	spec->len++;
+
+	if (core_relo_is_enumval_based(relo->kind)) {
+		if (!btf_is_any_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t))
+			return -EINVAL;
+
+		/* record enumerator name in a first accessor */
+		name_off = btf_is_enum(t) ? btf_enum(t)[access_idx].name_off
+					  : btf_enum64(t)[access_idx].name_off;
+		acc->name = btf__name_by_offset(btf, name_off);
+		return 0;
+	}
+
+	if (!core_relo_is_field_based(relo->kind))
+		return -EINVAL;
+
+	sz = btf__resolve_size(btf, id);
+	if (sz < 0)
+		return sz;
+	spec->bit_offset = access_idx * sz * 8;
+
+	for (i = 1; i < spec->raw_len; i++) {
+		t = skip_mods_and_typedefs(btf, id, &id);
+		if (!t)
+			return -EINVAL;
+
+		access_idx = spec->raw_spec[i];
+		acc = &spec->spec[spec->len];
+
+		if (btf_is_composite(t)) {
+			const struct btf_member *m;
+			__u32 bit_offset;
+
+			if (access_idx >= btf_vlen(t))
+				return -EINVAL;
+
+			bit_offset = btf_member_bit_offset(t, access_idx);
+			spec->bit_offset += bit_offset;
+
+			m = btf_members(t) + access_idx;
+			if (m->name_off) {
+				name = btf__name_by_offset(btf, m->name_off);
+				if (str_is_empty(name))
+					return -EINVAL;
+
+				acc->type_id = id;
+				acc->idx = access_idx;
+				acc->name = name;
+				spec->len++;
+			}
+
+			id = m->type;
+		} else if (btf_is_array(t)) {
+			const struct btf_array *a = btf_array(t);
+			bool flex;
+
+			t = skip_mods_and_typedefs(btf, a->type, &id);
+			if (!t)
+				return -EINVAL;
+
+			flex = is_flex_arr(btf, acc - 1, a);
+			if (!flex && access_idx >= a->nelems)
+				return -EINVAL;
+
+			spec->spec[spec->len].type_id = id;
+			spec->spec[spec->len].idx = access_idx;
+			spec->len++;
+
+			sz = btf__resolve_size(btf, id);
+			if (sz < 0)
+				return sz;
+			spec->bit_offset += access_idx * sz * 8;
+		} else {
+			pr_warn("prog '%s': relo for [%u] %s (at idx %d) captures type [%u] of unexpected kind %s\n",
+				prog_name, relo->type_id, spec_str, i, id, btf_kind_str(t));
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/* Check two types for compatibility for the purpose of field access
+ * relocation. const/volatile/restrict and typedefs are skipped to ensure we
+ * are relocating semantically compatible entities:
+ *   - any two STRUCTs/UNIONs are compatible and can be mixed;
+ *   - any two FWDs are compatible, if their names match (modulo flavor suffix);
+ *   - any two PTRs are always compatible;
+ *   - for ENUMs, names should be the same (ignoring flavor suffix) or at
+ *     least one of enums should be anonymous;
+ *   - for ENUMs, check sizes, names are ignored;
+ *   - for INT, size and signedness are ignored;
+ *   - any two FLOATs are always compatible;
+ *   - for ARRAY, dimensionality is ignored, element types are checked for
+ *     compatibility recursively;
+ *   - everything else shouldn't be ever a target of relocation.
+ * These rules are not set in stone and probably will be adjusted as we get
+ * more experience with using BPF CO-RE relocations.
+ */
+static int bpf_core_fields_are_compat(const struct btf *local_btf,
+				      __u32 local_id,
+				      const struct btf *targ_btf,
+				      __u32 targ_id)
+{
+	const struct btf_type *local_type, *targ_type;
+
+recur:
+	local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
+	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
+	if (!local_type || !targ_type)
+		return -EINVAL;
+
+	if (btf_is_composite(local_type) && btf_is_composite(targ_type))
+		return 1;
+	if (!btf_kind_core_compat(local_type, targ_type))
+		return 0;
+
+	switch (btf_kind(local_type)) {
+	case BTF_KIND_PTR:
+	case BTF_KIND_FLOAT:
+		return 1;
+	case BTF_KIND_FWD:
+	case BTF_KIND_ENUM64:
+	case BTF_KIND_ENUM: {
+		const char *local_name, *targ_name;
+		size_t local_len, targ_len;
+
+		local_name = btf__name_by_offset(local_btf,
+						 local_type->name_off);
+		targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
+		local_len = bpf_core_essential_name_len(local_name);
+		targ_len = bpf_core_essential_name_len(targ_name);
+		/* one of them is anonymous or both w/ same flavor-less names */
+		return local_len == 0 || targ_len == 0 ||
+		       (local_len == targ_len &&
+			strncmp(local_name, targ_name, local_len) == 0);
+	}
+	case BTF_KIND_INT:
+		/* just reject deprecated bitfield-like integers; all other
+		 * integers are by default compatible between each other
+		 */
+		return btf_int_offset(local_type) == 0 &&
+		       btf_int_offset(targ_type) == 0;
+	case BTF_KIND_ARRAY:
+		local_id = btf_array(local_type)->type;
+		targ_id = btf_array(targ_type)->type;
+		goto recur;
+	default:
+		return 0;
+	}
+}
+
+/*
+ * Given single high-level named field accessor in local type, find
+ * corresponding high-level accessor for a target type. Along the way,
+ * maintain low-level spec for target as well. Also keep updating target
+ * bit offset.
+ *
+ * Searching is performed through recursive exhaustive enumeration of all
+ * fields of a struct/union. If there are any anonymous (embedded)
+ * structs/unions, they are recursively searched as well. If field with
+ * desired name is found, check compatibility between local and target types,
+ * before returning result.
+ *
+ * 1 is returned, if field is found.
+ * 0 is returned if no compatible field is found.
+ * <0 is returned on error.
+ */
+static int bpf_core_match_member(const struct btf *local_btf,
+				 const struct bpf_core_accessor *local_acc,
+				 const struct btf *targ_btf,
+				 __u32 targ_id,
+				 struct bpf_core_spec *spec,
+				 __u32 *next_targ_id)
+{
+	const struct btf_type *local_type, *targ_type;
+	const struct btf_member *local_member, *m;
+	const char *local_name, *targ_name;
+	__u32 local_id;
+	int i, n, found;
+
+	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
+	if (!targ_type)
+		return -EINVAL;
+	if (!btf_is_composite(targ_type))
+		return 0;
+
+	local_id = local_acc->type_id;
+	local_type = btf_type_by_id(local_btf, local_id);
+	local_member = btf_members(local_type) + local_acc->idx;
+	local_name = btf__name_by_offset(local_btf, local_member->name_off);
+
+	n = btf_vlen(targ_type);
+	m = btf_members(targ_type);
+	for (i = 0; i < n; i++, m++) {
+		__u32 bit_offset;
+
+		bit_offset = btf_member_bit_offset(targ_type, i);
+
+		/* too deep struct/union/array nesting */
+		if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
+			return -E2BIG;
+
+		/* speculate this member will be the good one */
+		spec->bit_offset += bit_offset;
+		spec->raw_spec[spec->raw_len++] = i;
+
+		targ_name = btf__name_by_offset(targ_btf, m->name_off);
+		if (str_is_empty(targ_name)) {
+			/* embedded struct/union, we need to go deeper */
+			found = bpf_core_match_member(local_btf, local_acc,
+						      targ_btf, m->type,
+						      spec, next_targ_id);
+			if (found) /* either found or error */
+				return found;
+		} else if (strcmp(local_name, targ_name) == 0) {
+			/* matching named field */
+			struct bpf_core_accessor *targ_acc;
+
+			targ_acc = &spec->spec[spec->len++];
+			targ_acc->type_id = targ_id;
+			targ_acc->idx = i;
+			targ_acc->name = targ_name;
+
+			*next_targ_id = m->type;
+			found = bpf_core_fields_are_compat(local_btf,
+							   local_member->type,
+							   targ_btf, m->type);
+			if (!found)
+				spec->len--; /* pop accessor */
+			return found;
+		}
+		/* member turned out not to be what we looked for */
+		spec->bit_offset -= bit_offset;
+		spec->raw_len--;
+	}
+
+	return 0;
+}
+
+/*
+ * Try to match local spec to a target type and, if successful, produce full
+ * target spec (high-level, low-level + bit offset).
+ */
+static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
+			       const struct btf *targ_btf, __u32 targ_id,
+			       struct bpf_core_spec *targ_spec)
+{
+	const struct btf_type *targ_type;
+	const struct bpf_core_accessor *local_acc;
+	struct bpf_core_accessor *targ_acc;
+	int i, sz, matched;
+	__u32 name_off;
+
+	memset(targ_spec, 0, sizeof(*targ_spec));
+	targ_spec->btf = targ_btf;
+	targ_spec->root_type_id = targ_id;
+	targ_spec->relo_kind = local_spec->relo_kind;
+
+	if (core_relo_is_type_based(local_spec->relo_kind)) {
+		if (local_spec->relo_kind == BPF_CORE_TYPE_MATCHES)
+			return bpf_core_types_match(local_spec->btf,
+						    local_spec->root_type_id,
+						    targ_btf, targ_id);
+		else
+			return bpf_core_types_are_compat(local_spec->btf,
+							 local_spec->root_type_id,
+							 targ_btf, targ_id);
+	}
+
+	local_acc = &local_spec->spec[0];
+	targ_acc = &targ_spec->spec[0];
+
+	if (core_relo_is_enumval_based(local_spec->relo_kind)) {
+		size_t local_essent_len, targ_essent_len;
+		const char *targ_name;
+
+		/* has to resolve to an enum */
+		targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id);
+		if (!btf_is_any_enum(targ_type))
+			return 0;
+
+		local_essent_len = bpf_core_essential_name_len(local_acc->name);
+
+		for (i = 0; i < btf_vlen(targ_type); i++) {
+			if (btf_is_enum(targ_type))
+				name_off = btf_enum(targ_type)[i].name_off;
+			else
+				name_off = btf_enum64(targ_type)[i].name_off;
+
+			targ_name = btf__name_by_offset(targ_spec->btf, name_off);
+			targ_essent_len = bpf_core_essential_name_len(targ_name);
+			if (targ_essent_len != local_essent_len)
+				continue;
+			if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) {
+				targ_acc->type_id = targ_id;
+				targ_acc->idx = i;
+				targ_acc->name = targ_name;
+				targ_spec->len++;
+				targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
+				targ_spec->raw_len++;
+				return 1;
+			}
+		}
+		return 0;
+	}
+
+	if (!core_relo_is_field_based(local_spec->relo_kind))
+		return -EINVAL;
+
+	for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
+		targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
+						   &targ_id);
+		if (!targ_type)
+			return -EINVAL;
+
+		if (local_acc->name) {
+			matched = bpf_core_match_member(local_spec->btf,
+							local_acc,
+							targ_btf, targ_id,
+							targ_spec, &targ_id);
+			if (matched <= 0)
+				return matched;
+		} else {
+			/* for i=0, targ_id is already treated as array element
+			 * type (because it's the original struct), for others
+			 * we should find array element type first
+			 */
+			if (i > 0) {
+				const struct btf_array *a;
+				bool flex;
+
+				if (!btf_is_array(targ_type))
+					return 0;
+
+				a = btf_array(targ_type);
+				flex = is_flex_arr(targ_btf, targ_acc - 1, a);
+				if (!flex && local_acc->idx >= a->nelems)
+					return 0;
+				if (!skip_mods_and_typedefs(targ_btf, a->type,
+							    &targ_id))
+					return -EINVAL;
+			}
+
+			/* too deep struct/union/array nesting */
+			if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
+				return -E2BIG;
+
+			targ_acc->type_id = targ_id;
+			targ_acc->idx = local_acc->idx;
+			targ_acc->name = NULL;
+			targ_spec->len++;
+			targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
+			targ_spec->raw_len++;
+
+			sz = btf__resolve_size(targ_btf, targ_id);
+			if (sz < 0)
+				return sz;
+			targ_spec->bit_offset += local_acc->idx * sz * 8;
+		}
+	}
+
+	return 1;
+}
+
+static int bpf_core_calc_field_relo(const char *prog_name,
+				    const struct bpf_core_relo *relo,
+				    const struct bpf_core_spec *spec,
+				    __u64 *val, __u32 *field_sz, __u32 *type_id,
+				    bool *validate)
+{
+	const struct bpf_core_accessor *acc;
+	const struct btf_type *t;
+	__u32 byte_off, byte_sz, bit_off, bit_sz, field_type_id, elem_id;
+	const struct btf_member *m;
+	const struct btf_type *mt;
+	bool bitfield;
+	__s64 sz;
+
+	*field_sz = 0;
+
+	if (relo->kind == BPF_CORE_FIELD_EXISTS) {
+		*val = spec ? 1 : 0;
+		return 0;
+	}
+
+	if (!spec)
+		return -EUCLEAN; /* request instruction poisoning */
+
+	acc = &spec->spec[spec->len - 1];
+	t = btf_type_by_id(spec->btf, acc->type_id);
+
+	/* a[n] accessor needs special handling */
+	if (!acc->name) {
+		if (relo->kind == BPF_CORE_FIELD_BYTE_OFFSET) {
+			*val = spec->bit_offset / 8;
+			/* remember field size for load/store mem size;
+			 * note, for arrays we care about individual element
+			 * sizes, not the overall array size
+			 */
+			t = skip_mods_and_typedefs(spec->btf, acc->type_id, &elem_id);
+			while (btf_is_array(t))
+				t = skip_mods_and_typedefs(spec->btf, btf_array(t)->type, &elem_id);
+			sz = btf__resolve_size(spec->btf, elem_id);
+			if (sz < 0)
+				return -EINVAL;
+			*field_sz = sz;
+			*type_id = acc->type_id;
+		} else if (relo->kind == BPF_CORE_FIELD_BYTE_SIZE) {
+			sz = btf__resolve_size(spec->btf, acc->type_id);
+			if (sz < 0)
+				return -EINVAL;
+			*val = sz;
+		} else {
+			pr_warn("prog '%s': relo %u at insn #%u can't be applied to array access\n",
+				prog_name, relo->kind, relo->insn_off / 8);
+			return -EINVAL;
+		}
+		if (validate)
+			*validate = true;
+		return 0;
+	}
+
+	m = btf_members(t) + acc->idx;
+	mt = skip_mods_and_typedefs(spec->btf, m->type, &field_type_id);
+	bit_off = spec->bit_offset;
+	bit_sz = btf_member_bitfield_size(t, acc->idx);
+
+	bitfield = bit_sz > 0;
+	if (bitfield) {
+		byte_sz = mt->size;
+		byte_off = bit_off / 8 / byte_sz * byte_sz;
+		/* figure out smallest int size necessary for bitfield load */
+		while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
+			if (byte_sz >= 8) {
+				/* bitfield can't be read with 64-bit read */
+				pr_warn("prog '%s': relo %u at insn #%u can't be satisfied for bitfield\n",
+					prog_name, relo->kind, relo->insn_off / 8);
+				return -E2BIG;
+			}
+			byte_sz *= 2;
+			byte_off = bit_off / 8 / byte_sz * byte_sz;
+		}
+	} else {
+		sz = btf__resolve_size(spec->btf, field_type_id);
+		if (sz < 0)
+			return -EINVAL;
+		byte_sz = sz;
+		byte_off = spec->bit_offset / 8;
+		bit_sz = byte_sz * 8;
+	}
+
+	/* for bitfields, all the relocatable aspects are ambiguous and we
+	 * might disagree with compiler, so turn off validation of expected
+	 * value, except for signedness
+	 */
+	if (validate)
+		*validate = !bitfield;
+
+	switch (relo->kind) {
+	case BPF_CORE_FIELD_BYTE_OFFSET:
+		*val = byte_off;
+		if (!bitfield) {
+			/* remember field size for load/store mem size;
+			 * note, for arrays we care about individual element
+			 * sizes, not the overall array size
+			 */
+			t = skip_mods_and_typedefs(spec->btf, field_type_id, &elem_id);
+			while (btf_is_array(t))
+				t = skip_mods_and_typedefs(spec->btf, btf_array(t)->type, &elem_id);
+			sz = btf__resolve_size(spec->btf, elem_id);
+			if (sz < 0)
+				return -EINVAL;
+			*field_sz = sz;
+			*type_id = field_type_id;
+		}
+		break;
+	case BPF_CORE_FIELD_BYTE_SIZE:
+		*val = byte_sz;
+		break;
+	case BPF_CORE_FIELD_SIGNED:
+		*val = (btf_is_any_enum(mt) && BTF_INFO_KFLAG(mt->info)) ||
+		       (btf_is_int(mt) && (btf_int_encoding(mt) & BTF_INT_SIGNED));
+		if (validate)
+			*validate = true; /* signedness is never ambiguous */
+		break;
+	case BPF_CORE_FIELD_LSHIFT_U64:
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+		*val = 64 - (bit_off + bit_sz - byte_off  * 8);
+#else
+		*val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
+#endif
+		break;
+	case BPF_CORE_FIELD_RSHIFT_U64:
+		*val = 64 - bit_sz;
+		if (validate)
+			*validate = true; /* right shift is never ambiguous */
+		break;
+	case BPF_CORE_FIELD_EXISTS:
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
+				   const struct bpf_core_spec *spec,
+				   __u64 *val, bool *validate)
+{
+	__s64 sz;
+
+	/* by default, always check expected value in bpf_insn */
+	if (validate)
+		*validate = true;
+
+	/* type-based relos return zero when target type is not found */
+	if (!spec) {
+		*val = 0;
+		return 0;
+	}
+
+	switch (relo->kind) {
+	case BPF_CORE_TYPE_ID_TARGET:
+		*val = spec->root_type_id;
+		/* type ID, embedded in bpf_insn, might change during linking,
+		 * so enforcing it is pointless
+		 */
+		if (validate)
+			*validate = false;
+		break;
+	case BPF_CORE_TYPE_EXISTS:
+	case BPF_CORE_TYPE_MATCHES:
+		*val = 1;
+		break;
+	case BPF_CORE_TYPE_SIZE:
+		sz = btf__resolve_size(spec->btf, spec->root_type_id);
+		if (sz < 0)
+			return -EINVAL;
+		*val = sz;
+		break;
+	case BPF_CORE_TYPE_ID_LOCAL:
+	/* BPF_CORE_TYPE_ID_LOCAL is handled specially and shouldn't get here */
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
+				      const struct bpf_core_spec *spec,
+				      __u64 *val)
+{
+	const struct btf_type *t;
+
+	switch (relo->kind) {
+	case BPF_CORE_ENUMVAL_EXISTS:
+		*val = spec ? 1 : 0;
+		break;
+	case BPF_CORE_ENUMVAL_VALUE:
+		if (!spec)
+			return -EUCLEAN; /* request instruction poisoning */
+		t = btf_type_by_id(spec->btf, spec->spec[0].type_id);
+		if (btf_is_enum(t))
+			*val = btf_enum(t)[spec->spec[0].idx].val;
+		else
+			*val = btf_enum64_value(btf_enum64(t) + spec->spec[0].idx);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+/* Calculate original and target relocation values, given local and target
+ * specs and relocation kind. These values are calculated for each candidate.
+ * If there are multiple candidates, resulting values should all be consistent
+ * with each other. Otherwise, libbpf will refuse to proceed due to ambiguity.
+ * If instruction has to be poisoned, *poison will be set to true.
+ */
+static int bpf_core_calc_relo(const char *prog_name,
+			      const struct bpf_core_relo *relo,
+			      int relo_idx,
+			      const struct bpf_core_spec *local_spec,
+			      const struct bpf_core_spec *targ_spec,
+			      struct bpf_core_relo_res *res)
+{
+	int err = -EOPNOTSUPP;
+
+	res->orig_val = 0;
+	res->new_val = 0;
+	res->poison = false;
+	res->validate = true;
+	res->fail_memsz_adjust = false;
+	res->orig_sz = res->new_sz = 0;
+	res->orig_type_id = res->new_type_id = 0;
+
+	if (core_relo_is_field_based(relo->kind)) {
+		err = bpf_core_calc_field_relo(prog_name, relo, local_spec,
+					       &res->orig_val, &res->orig_sz,
+					       &res->orig_type_id, &res->validate);
+		err = err ?: bpf_core_calc_field_relo(prog_name, relo, targ_spec,
+						      &res->new_val, &res->new_sz,
+						      &res->new_type_id, NULL);
+		if (err)
+			goto done;
+		/* Validate if it's safe to adjust load/store memory size.
+		 * Adjustments are performed only if original and new memory
+		 * sizes differ.
+		 */
+		res->fail_memsz_adjust = false;
+		if (res->orig_sz != res->new_sz) {
+			const struct btf_type *orig_t, *new_t;
+
+			orig_t = btf_type_by_id(local_spec->btf, res->orig_type_id);
+			new_t = btf_type_by_id(targ_spec->btf, res->new_type_id);
+
+			/* There are two use cases in which it's safe to
+			 * adjust load/store's mem size:
+			 *   - reading a 32-bit kernel pointer, while on BPF
+			 *   size pointers are always 64-bit; in this case
+			 *   it's safe to "downsize" instruction size due to
+			 *   pointer being treated as unsigned integer with
+			 *   zero-extended upper 32-bits;
+			 *   - reading unsigned integers, again due to
+			 *   zero-extension is preserving the value correctly.
+			 *
+			 * In all other cases it's incorrect to attempt to
+			 * load/store field because read value will be
+			 * incorrect, so we poison relocated instruction.
+			 */
+			if (btf_is_ptr(orig_t) && btf_is_ptr(new_t))
+				goto done;
+			if (btf_is_int(orig_t) && btf_is_int(new_t) &&
+			    btf_int_encoding(orig_t) != BTF_INT_SIGNED &&
+			    btf_int_encoding(new_t) != BTF_INT_SIGNED)
+				goto done;
+
+			/* mark as invalid mem size adjustment, but this will
+			 * only be checked for LDX/STX/ST insns
+			 */
+			res->fail_memsz_adjust = true;
+		}
+	} else if (core_relo_is_type_based(relo->kind)) {
+		err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val, &res->validate);
+		err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val, NULL);
+	} else if (core_relo_is_enumval_based(relo->kind)) {
+		err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val);
+		err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val);
+	}
+
+done:
+	if (err == -EUCLEAN) {
+		/* EUCLEAN is used to signal instruction poisoning request */
+		res->poison = true;
+		err = 0;
+	} else if (err == -EOPNOTSUPP) {
+		/* EOPNOTSUPP means unknown/unsupported relocation */
+		pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%u) at insn #%u\n",
+			prog_name, relo_idx, core_relo_kind_str(relo->kind),
+			relo->kind, relo->insn_off / 8);
+	}
+
+	return err;
+}
+
+/*
+ * Turn instruction for which CO_RE relocation failed into invalid one with
+ * distinct signature.
+ */
+static void bpf_core_poison_insn(const char *prog_name, int relo_idx,
+				 int insn_idx, struct bpf_insn *insn)
+{
+	pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n",
+		 prog_name, relo_idx, insn_idx);
+	insn->code = BPF_JMP | BPF_CALL;
+	insn->dst_reg = 0;
+	insn->src_reg = 0;
+	insn->off = 0;
+	/* if this instruction is reachable (not a dead code),
+	 * verifier will complain with the following message:
+	 * invalid func unknown#195896080
+	 */
+	insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */
+}
+
+static int insn_bpf_size_to_bytes(struct bpf_insn *insn)
+{
+	switch (BPF_SIZE(insn->code)) {
+	case BPF_DW: return 8;
+	case BPF_W: return 4;
+	case BPF_H: return 2;
+	case BPF_B: return 1;
+	default: return -1;
+	}
+}
+
+static int insn_bytes_to_bpf_size(__u32 sz)
+{
+	switch (sz) {
+	case 8: return BPF_DW;
+	case 4: return BPF_W;
+	case 2: return BPF_H;
+	case 1: return BPF_B;
+	default: return -1;
+	}
+}
+
+/*
+ * Patch relocatable BPF instruction.
+ *
+ * Patched value is determined by relocation kind and target specification.
+ * For existence relocations target spec will be NULL if field/type is not found.
+ * Expected insn->imm value is determined using relocation kind and local
+ * spec, and is checked before patching instruction. If actual insn->imm value
+ * is wrong, bail out with error.
+ *
+ * Currently supported classes of BPF instruction are:
+ * 1. rX = <imm> (assignment with immediate operand);
+ * 2. rX += <imm> (arithmetic operations with immediate operand);
+ * 3. rX = <imm64> (load with 64-bit immediate value);
+ * 4. rX = *(T *)(rY + <off>), where T is one of {u8, u16, u32, u64};
+ * 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64};
+ * 6. *(T *)(rX + <off>) = <imm>, where T is one of {u8, u16, u32, u64}.
+ */
+int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
+			int insn_idx, const struct bpf_core_relo *relo,
+			int relo_idx, const struct bpf_core_relo_res *res)
+{
+	__u64 orig_val, new_val;
+	__u8 class;
+
+	class = BPF_CLASS(insn->code);
+
+	if (res->poison) {
+poison:
+		/* poison second part of ldimm64 to avoid confusing error from
+		 * verifier about "unknown opcode 00"
+		 */
+		if (is_ldimm64_insn(insn))
+			bpf_core_poison_insn(prog_name, relo_idx, insn_idx + 1, insn + 1);
+		bpf_core_poison_insn(prog_name, relo_idx, insn_idx, insn);
+		return 0;
+	}
+
+	orig_val = res->orig_val;
+	new_val = res->new_val;
+
+	switch (class) {
+	case BPF_ALU:
+	case BPF_ALU64:
+		if (BPF_SRC(insn->code) != BPF_K)
+			return -EINVAL;
+		if (res->validate && insn->imm != orig_val) {
+			pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %d, exp %llu -> %llu\n",
+				prog_name, relo_idx,
+				insn_idx, insn->imm, (unsigned long long)orig_val,
+				(unsigned long long)new_val);
+			return -EINVAL;
+		}
+		orig_val = insn->imm;
+		insn->imm = new_val;
+		pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %llu -> %llu\n",
+			 prog_name, relo_idx, insn_idx,
+			 (unsigned long long)orig_val, (unsigned long long)new_val);
+		break;
+	case BPF_LDX:
+	case BPF_ST:
+	case BPF_STX:
+		if (res->validate && insn->off != orig_val) {
+			pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %d, exp %llu -> %llu\n",
+				prog_name, relo_idx, insn_idx, insn->off, (unsigned long long)orig_val,
+				(unsigned long long)new_val);
+			return -EINVAL;
+		}
+		if (new_val > SHRT_MAX) {
+			pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %llu\n",
+				prog_name, relo_idx, insn_idx, (unsigned long long)new_val);
+			return -ERANGE;
+		}
+		if (res->fail_memsz_adjust) {
+			pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) accesses field incorrectly. "
+				"Make sure you are accessing pointers, unsigned integers, or fields of matching type and size.\n",
+				prog_name, relo_idx, insn_idx);
+			goto poison;
+		}
+
+		orig_val = insn->off;
+		insn->off = new_val;
+		pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %llu -> %llu\n",
+			 prog_name, relo_idx, insn_idx, (unsigned long long)orig_val,
+			 (unsigned long long)new_val);
+
+		if (res->new_sz != res->orig_sz) {
+			int insn_bytes_sz, insn_bpf_sz;
+
+			insn_bytes_sz = insn_bpf_size_to_bytes(insn);
+			if (insn_bytes_sz != res->orig_sz) {
+				pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) unexpected mem size: got %d, exp %u\n",
+					prog_name, relo_idx, insn_idx, insn_bytes_sz, res->orig_sz);
+				return -EINVAL;
+			}
+
+			insn_bpf_sz = insn_bytes_to_bpf_size(res->new_sz);
+			if (insn_bpf_sz < 0) {
+				pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) invalid new mem size: %u\n",
+					prog_name, relo_idx, insn_idx, res->new_sz);
+				return -EINVAL;
+			}
+
+			insn->code = BPF_MODE(insn->code) | insn_bpf_sz | BPF_CLASS(insn->code);
+			pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) mem_sz %u -> %u\n",
+				 prog_name, relo_idx, insn_idx, res->orig_sz, res->new_sz);
+		}
+		break;
+	case BPF_LD: {
+		__u64 imm;
+
+		if (!is_ldimm64_insn(insn) ||
+		    insn[0].src_reg != 0 || insn[0].off != 0 ||
+		    insn[1].code != 0 || insn[1].dst_reg != 0 ||
+		    insn[1].src_reg != 0 || insn[1].off != 0) {
+			pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n",
+				prog_name, relo_idx, insn_idx);
+			return -EINVAL;
+		}
+
+		imm = (__u32)insn[0].imm | ((__u64)insn[1].imm << 32);
+		if (res->validate && imm != orig_val) {
+			pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %llu -> %llu\n",
+				prog_name, relo_idx,
+				insn_idx, (unsigned long long)imm,
+				(unsigned long long)orig_val, (unsigned long long)new_val);
+			return -EINVAL;
+		}
+
+		insn[0].imm = new_val;
+		insn[1].imm = new_val >> 32;
+		pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %llu\n",
+			 prog_name, relo_idx, insn_idx,
+			 (unsigned long long)imm, (unsigned long long)new_val);
+		break;
+	}
+	default:
+		pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n",
+			prog_name, relo_idx, insn_idx, insn->code,
+			(unsigned)insn->src_reg, (unsigned)insn->dst_reg, (unsigned)insn->off, (unsigned)insn->imm);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Output spec definition in the format:
+ * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
+ * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
+ */
+int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec)
+{
+	const struct btf_type *t;
+	const char *s;
+	__u32 type_id;
+	int i, len = 0;
+
+#define append_buf(fmt, args...)				\
+	({							\
+		int r;						\
+		r = snprintf(buf, buf_sz, fmt, ##args);		\
+		len += r;					\
+		if (r >= buf_sz)				\
+			r = buf_sz;				\
+		buf += r;					\
+		buf_sz -= r;					\
+	})
+
+	type_id = spec->root_type_id;
+	t = btf_type_by_id(spec->btf, type_id);
+	s = btf__name_by_offset(spec->btf, t->name_off);
+
+	append_buf("<%s> [%u] %s %s",
+		   core_relo_kind_str(spec->relo_kind),
+		   type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
+
+	if (core_relo_is_type_based(spec->relo_kind))
+		return len;
+
+	if (core_relo_is_enumval_based(spec->relo_kind)) {
+		t = skip_mods_and_typedefs(spec->btf, type_id, NULL);
+		if (btf_is_enum(t)) {
+			const struct btf_enum *e;
+			const char *fmt_str;
+
+			e = btf_enum(t) + spec->raw_spec[0];
+			s = btf__name_by_offset(spec->btf, e->name_off);
+			fmt_str = BTF_INFO_KFLAG(t->info) ? "::%s = %d" : "::%s = %u";
+			append_buf(fmt_str, s, e->val);
+		} else {
+			const struct btf_enum64 *e;
+			const char *fmt_str;
+
+			e = btf_enum64(t) + spec->raw_spec[0];
+			s = btf__name_by_offset(spec->btf, e->name_off);
+			fmt_str = BTF_INFO_KFLAG(t->info) ? "::%s = %lld" : "::%s = %llu";
+			append_buf(fmt_str, s, (unsigned long long)btf_enum64_value(e));
+		}
+		return len;
+	}
+
+	if (core_relo_is_field_based(spec->relo_kind)) {
+		for (i = 0; i < spec->len; i++) {
+			if (spec->spec[i].name)
+				append_buf(".%s", spec->spec[i].name);
+			else if (i > 0 || spec->spec[i].idx > 0)
+				append_buf("[%u]", spec->spec[i].idx);
+		}
+
+		append_buf(" (");
+		for (i = 0; i < spec->raw_len; i++)
+			append_buf("%s%d", i == 0 ? "" : ":", spec->raw_spec[i]);
+
+		if (spec->bit_offset % 8)
+			append_buf(" @ offset %u.%u)", spec->bit_offset / 8, spec->bit_offset % 8);
+		else
+			append_buf(" @ offset %u)", spec->bit_offset / 8);
+		return len;
+	}
+
+	return len;
+#undef append_buf
+}
+
+/*
+ * Calculate CO-RE relocation target result.
+ *
+ * The outline and important points of the algorithm:
+ * 1. For given local type, find corresponding candidate target types.
+ *    Candidate type is a type with the same "essential" name, ignoring
+ *    everything after last triple underscore (___). E.g., `sample`,
+ *    `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
+ *    for each other. Names with triple underscore are referred to as
+ *    "flavors" and are useful, among other things, to allow to
+ *    specify/support incompatible variations of the same kernel struct, which
+ *    might differ between different kernel versions and/or build
+ *    configurations.
+ *
+ *    N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
+ *    converter, when deduplicated BTF of a kernel still contains more than
+ *    one different types with the same name. In that case, ___2, ___3, etc
+ *    are appended starting from second name conflict. But start flavors are
+ *    also useful to be defined "locally", in BPF program, to extract same
+ *    data from incompatible changes between different kernel
+ *    versions/configurations. For instance, to handle field renames between
+ *    kernel versions, one can use two flavors of the struct name with the
+ *    same common name and use conditional relocations to extract that field,
+ *    depending on target kernel version.
+ * 2. For each candidate type, try to match local specification to this
+ *    candidate target type. Matching involves finding corresponding
+ *    high-level spec accessors, meaning that all named fields should match,
+ *    as well as all array accesses should be within the actual bounds. Also,
+ *    types should be compatible (see bpf_core_fields_are_compat for details).
+ * 3. It is supported and expected that there might be multiple flavors
+ *    matching the spec. As long as all the specs resolve to the same set of
+ *    offsets across all candidates, there is no error. If there is any
+ *    ambiguity, CO-RE relocation will fail. This is necessary to accommodate
+ *    imperfection of BTF deduplication, which can cause slight duplication of
+ *    the same BTF type, if some directly or indirectly referenced (by
+ *    pointer) type gets resolved to different actual types in different
+ *    object files. If such a situation occurs, deduplicated BTF will end up
+ *    with two (or more) structurally identical types, which differ only in
+ *    types they refer to through pointer. This should be OK in most cases and
+ *    is not an error.
+ * 4. Candidate types search is performed by linearly scanning through all
+ *    types in target BTF. It is anticipated that this is overall more
+ *    efficient memory-wise and not significantly worse (if not better)
+ *    CPU-wise compared to prebuilding a map from all local type names to
+ *    a list of candidate type names. It's also sped up by caching resolved
+ *    list of matching candidates per each local "root" type ID, that has at
+ *    least one bpf_core_relo associated with it. This list is shared
+ *    between multiple relocations for the same type ID and is updated as some
+ *    of the candidates are pruned due to structural incompatibility.
+ */
+int bpf_core_calc_relo_insn(const char *prog_name,
+			    const struct bpf_core_relo *relo,
+			    int relo_idx,
+			    const struct btf *local_btf,
+			    struct bpf_core_cand_list *cands,
+			    struct bpf_core_spec *specs_scratch,
+			    struct bpf_core_relo_res *targ_res)
+{
+	struct bpf_core_spec *local_spec = &specs_scratch[0];
+	struct bpf_core_spec *cand_spec = &specs_scratch[1];
+	struct bpf_core_spec *targ_spec = &specs_scratch[2];
+	struct bpf_core_relo_res cand_res;
+	const struct btf_type *local_type;
+	const char *local_name;
+	__u32 local_id;
+	char spec_buf[256];
+	int i, j, err;
+
+	local_id = relo->type_id;
+	local_type = btf_type_by_id(local_btf, local_id);
+	local_name = btf__name_by_offset(local_btf, local_type->name_off);
+	if (!local_name)
+		return -EINVAL;
+
+	err = bpf_core_parse_spec(prog_name, local_btf, relo, local_spec);
+	if (err) {
+		const char *spec_str;
+
+		spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
+		pr_warn("prog '%s': relo #%d: parsing [%u] %s %s + %s failed: %d\n",
+			prog_name, relo_idx, local_id, btf_kind_str(local_type),
+			str_is_empty(local_name) ? "<anon>" : local_name,
+			spec_str ?: "<?>", err);
+		return -EINVAL;
+	}
+
+	bpf_core_format_spec(spec_buf, sizeof(spec_buf), local_spec);
+	pr_debug("prog '%s': relo #%d: %s\n", prog_name, relo_idx, spec_buf);
+
+	/* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
+	if (relo->kind == BPF_CORE_TYPE_ID_LOCAL) {
+		/* bpf_insn's imm value could get out of sync during linking */
+		memset(targ_res, 0, sizeof(*targ_res));
+		targ_res->validate = false;
+		targ_res->poison = false;
+		targ_res->orig_val = local_spec->root_type_id;
+		targ_res->new_val = local_spec->root_type_id;
+		return 0;
+	}
+
+	/* libbpf doesn't support candidate search for anonymous types */
+	if (str_is_empty(local_name)) {
+		pr_warn("prog '%s': relo #%d: <%s> (%u) relocation doesn't support anonymous types\n",
+			prog_name, relo_idx, core_relo_kind_str(relo->kind), relo->kind);
+		return -EOPNOTSUPP;
+	}
+
+	for (i = 0, j = 0; i < cands->len; i++) {
+		err = bpf_core_spec_match(local_spec, cands->cands[i].btf,
+					  cands->cands[i].id, cand_spec);
+		if (err < 0) {
+			bpf_core_format_spec(spec_buf, sizeof(spec_buf), cand_spec);
+			pr_warn("prog '%s': relo #%d: error matching candidate #%d %s: %d\n",
+				prog_name, relo_idx, i, spec_buf, err);
+			return err;
+		}
+
+		bpf_core_format_spec(spec_buf, sizeof(spec_buf), cand_spec);
+		pr_debug("prog '%s': relo #%d: %s candidate #%d %s\n", prog_name,
+			 relo_idx, err == 0 ? "non-matching" : "matching", i, spec_buf);
+
+		if (err == 0)
+			continue;
+
+		err = bpf_core_calc_relo(prog_name, relo, relo_idx, local_spec, cand_spec, &cand_res);
+		if (err)
+			return err;
+
+		if (j == 0) {
+			*targ_res = cand_res;
+			*targ_spec = *cand_spec;
+		} else if (cand_spec->bit_offset != targ_spec->bit_offset) {
+			/* if there are many field relo candidates, they
+			 * should all resolve to the same bit offset
+			 */
+			pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n",
+				prog_name, relo_idx, cand_spec->bit_offset,
+				targ_spec->bit_offset);
+			return -EINVAL;
+		} else if (cand_res.poison != targ_res->poison ||
+			   cand_res.new_val != targ_res->new_val) {
+			/* all candidates should result in the same relocation
+			 * decision and value, otherwise it's dangerous to
+			 * proceed due to ambiguity
+			 */
+			pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %llu != %s %llu\n",
+				prog_name, relo_idx,
+				cand_res.poison ? "failure" : "success",
+				(unsigned long long)cand_res.new_val,
+				targ_res->poison ? "failure" : "success",
+				(unsigned long long)targ_res->new_val);
+			return -EINVAL;
+		}
+
+		cands->cands[j++] = cands->cands[i];
+	}
+
+	/*
+	 * For BPF_CORE_FIELD_EXISTS relo or when used BPF program has field
+	 * existence checks or kernel version/config checks, it's expected
+	 * that we might not find any candidates. In this case, if field
+	 * wasn't found in any candidate, the list of candidates shouldn't
+	 * change at all, we'll just handle relocating appropriately,
+	 * depending on relo's kind.
+	 */
+	if (j > 0)
+		cands->len = j;
+
+	/*
+	 * If no candidates were found, it might be both a programmer error,
+	 * as well as expected case, depending whether instruction w/
+	 * relocation is guarded in some way that makes it unreachable (dead
+	 * code) if relocation can't be resolved. This is handled in
+	 * bpf_core_patch_insn() uniformly by replacing that instruction with
+	 * BPF helper call insn (using invalid helper ID). If that instruction
+	 * is indeed unreachable, then it will be ignored and eliminated by
+	 * verifier. If it was an error, then verifier will complain and point
+	 * to a specific instruction number in its log.
+	 */
+	if (j == 0) {
+		pr_debug("prog '%s': relo #%d: no matching targets found\n",
+			 prog_name, relo_idx);
+
+		/* calculate single target relo result explicitly */
+		err = bpf_core_calc_relo(prog_name, relo, relo_idx, local_spec, NULL, targ_res);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static bool bpf_core_names_match(const struct btf *local_btf, size_t local_name_off,
+				 const struct btf *targ_btf, size_t targ_name_off)
+{
+	const char *local_n, *targ_n;
+	size_t local_len, targ_len;
+
+	local_n = btf__name_by_offset(local_btf, local_name_off);
+	targ_n = btf__name_by_offset(targ_btf, targ_name_off);
+
+	if (str_is_empty(targ_n))
+		return str_is_empty(local_n);
+
+	targ_len = bpf_core_essential_name_len(targ_n);
+	local_len = bpf_core_essential_name_len(local_n);
+
+	return targ_len == local_len && strncmp(local_n, targ_n, local_len) == 0;
+}
+
+static int bpf_core_enums_match(const struct btf *local_btf, const struct btf_type *local_t,
+				const struct btf *targ_btf, const struct btf_type *targ_t)
+{
+	__u32 local_vlen = btf_vlen(local_t);
+	__u32 targ_vlen = btf_vlen(targ_t);
+	int i, j;
+
+	if (local_t->size != targ_t->size)
+		return 0;
+
+	if (local_vlen > targ_vlen)
+		return 0;
+
+	/* iterate over the local enum's variants and make sure each has
+	 * a symbolic name correspondent in the target
+	 */
+	for (i = 0; i < local_vlen; i++) {
+		bool matched = false;
+		__u32 local_n_off, targ_n_off;
+
+		local_n_off = btf_is_enum(local_t) ? btf_enum(local_t)[i].name_off :
+						     btf_enum64(local_t)[i].name_off;
+
+		for (j = 0; j < targ_vlen; j++) {
+			targ_n_off = btf_is_enum(targ_t) ? btf_enum(targ_t)[j].name_off :
+							   btf_enum64(targ_t)[j].name_off;
+
+			if (bpf_core_names_match(local_btf, local_n_off, targ_btf, targ_n_off)) {
+				matched = true;
+				break;
+			}
+		}
+
+		if (!matched)
+			return 0;
+	}
+	return 1;
+}
+
+static int bpf_core_composites_match(const struct btf *local_btf, const struct btf_type *local_t,
+				     const struct btf *targ_btf, const struct btf_type *targ_t,
+				     bool behind_ptr, int level)
+{
+	const struct btf_member *local_m = btf_members(local_t);
+	__u32 local_vlen = btf_vlen(local_t);
+	__u32 targ_vlen = btf_vlen(targ_t);
+	int i, j, err;
+
+	if (local_vlen > targ_vlen)
+		return 0;
+
+	/* check that all local members have a match in the target */
+	for (i = 0; i < local_vlen; i++, local_m++) {
+		const struct btf_member *targ_m = btf_members(targ_t);
+		bool matched = false;
+
+		for (j = 0; j < targ_vlen; j++, targ_m++) {
+			if (!bpf_core_names_match(local_btf, local_m->name_off,
+						  targ_btf, targ_m->name_off))
+				continue;
+
+			err = __bpf_core_types_match(local_btf, local_m->type, targ_btf,
+						     targ_m->type, behind_ptr, level - 1);
+			if (err < 0)
+				return err;
+			if (err > 0) {
+				matched = true;
+				break;
+			}
+		}
+
+		if (!matched)
+			return 0;
+	}
+	return 1;
+}
+
+/* Check that two types "match". This function assumes that root types were
+ * already checked for name match.
+ *
+ * The matching relation is defined as follows:
+ * - modifiers and typedefs are stripped (and, hence, effectively ignored)
+ * - generally speaking types need to be of same kind (struct vs. struct, union
+ *   vs. union, etc.)
+ *   - exceptions are struct/union behind a pointer which could also match a
+ *     forward declaration of a struct or union, respectively, and enum vs.
+ *     enum64 (see below)
+ * Then, depending on type:
+ * - integers:
+ *   - match if size and signedness match
+ * - arrays & pointers:
+ *   - target types are recursively matched
+ * - structs & unions:
+ *   - local members need to exist in target with the same name
+ *   - for each member we recursively check match unless it is already behind a
+ *     pointer, in which case we only check matching names and compatible kind
+ * - enums:
+ *   - local variants have to have a match in target by symbolic name (but not
+ *     numeric value)
+ *   - size has to match (but enum may match enum64 and vice versa)
+ * - function pointers:
+ *   - number and position of arguments in local type has to match target
+ *   - for each argument and the return value we recursively check match
+ */
+int __bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
+			   __u32 targ_id, bool behind_ptr, int level)
+{
+	const struct btf_type *local_t, *targ_t;
+	int depth = 32; /* max recursion depth */
+	__u16 local_k, targ_k;
+
+	if (level <= 0)
+		return -EINVAL;
+
+recur:
+	depth--;
+	if (depth < 0)
+		return -EINVAL;
+
+	local_t = skip_mods_and_typedefs(local_btf, local_id, &local_id);
+	targ_t = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
+	if (!local_t || !targ_t)
+		return -EINVAL;
+
+	/* While the name check happens after typedefs are skipped, root-level
+	 * typedefs would still be name-matched as that's the contract with
+	 * callers.
+	 */
+	if (!bpf_core_names_match(local_btf, local_t->name_off, targ_btf, targ_t->name_off))
+		return 0;
+
+	local_k = btf_kind(local_t);
+	targ_k = btf_kind(targ_t);
+
+	switch (local_k) {
+	case BTF_KIND_UNKN:
+		return local_k == targ_k;
+	case BTF_KIND_FWD: {
+		bool local_f = BTF_INFO_KFLAG(local_t->info);
+
+		if (behind_ptr) {
+			if (local_k == targ_k)
+				return local_f == BTF_INFO_KFLAG(targ_t->info);
+
+			/* for forward declarations kflag dictates whether the
+			 * target is a struct (0) or union (1)
+			 */
+			return (targ_k == BTF_KIND_STRUCT && !local_f) ||
+			       (targ_k == BTF_KIND_UNION && local_f);
+		} else {
+			if (local_k != targ_k)
+				return 0;
+
+			/* match if the forward declaration is for the same kind */
+			return local_f == BTF_INFO_KFLAG(targ_t->info);
+		}
+	}
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		if (!btf_is_any_enum(targ_t))
+			return 0;
+
+		return bpf_core_enums_match(local_btf, local_t, targ_btf, targ_t);
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+		if (behind_ptr) {
+			bool targ_f = BTF_INFO_KFLAG(targ_t->info);
+
+			if (local_k == targ_k)
+				return 1;
+
+			if (targ_k != BTF_KIND_FWD)
+				return 0;
+
+			return (local_k == BTF_KIND_UNION) == targ_f;
+		} else {
+			if (local_k != targ_k)
+				return 0;
+
+			return bpf_core_composites_match(local_btf, local_t, targ_btf, targ_t,
+							 behind_ptr, level);
+		}
+	case BTF_KIND_INT: {
+		__u8 local_sgn;
+		__u8 targ_sgn;
+
+		if (local_k != targ_k)
+			return 0;
+
+		local_sgn = btf_int_encoding(local_t) & BTF_INT_SIGNED;
+		targ_sgn = btf_int_encoding(targ_t) & BTF_INT_SIGNED;
+
+		return local_t->size == targ_t->size && local_sgn == targ_sgn;
+	}
+	case BTF_KIND_PTR:
+		if (local_k != targ_k)
+			return 0;
+
+		behind_ptr = true;
+
+		local_id = local_t->type;
+		targ_id = targ_t->type;
+		goto recur;
+	case BTF_KIND_ARRAY: {
+		const struct btf_array *local_array = btf_array(local_t);
+		const struct btf_array *targ_array = btf_array(targ_t);
+
+		if (local_k != targ_k)
+			return 0;
+
+		if (local_array->nelems != targ_array->nelems)
+			return 0;
+
+		local_id = local_array->type;
+		targ_id = targ_array->type;
+		goto recur;
+	}
+	case BTF_KIND_FUNC_PROTO: {
+		struct btf_param *local_p = btf_params(local_t);
+		struct btf_param *targ_p = btf_params(targ_t);
+		__u32 local_vlen = btf_vlen(local_t);
+		__u32 targ_vlen = btf_vlen(targ_t);
+		int i, err;
+
+		if (local_k != targ_k)
+			return 0;
+
+		if (local_vlen != targ_vlen)
+			return 0;
+
+		for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
+			err = __bpf_core_types_match(local_btf, local_p->type, targ_btf,
+						     targ_p->type, behind_ptr, level - 1);
+			if (err <= 0)
+				return err;
+		}
+
+		/* tail recurse for return type check */
+		local_id = local_t->type;
+		targ_id = targ_t->type;
+		goto recur;
+	}
+	default:
+		pr_warn("unexpected kind %s relocated, local [%u], target [%u]\n",
+			btf_kind_str(local_t), local_id, targ_id);
+		return 0;
+	}
+}
diff --git a/tools/lib/bpf/relo_core.h b/tools/lib/bpf/relo_core.h
new file mode 100644
index 000000000..1c0566daf
--- /dev/null
+++ b/tools/lib/bpf/relo_core.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (c) 2019 Facebook */
+
+#ifndef __RELO_CORE_H
+#define __RELO_CORE_H
+
+#include <linux/bpf.h>
+
+struct bpf_core_cand {
+	const struct btf *btf;
+	__u32 id;
+};
+
+/* dynamically sized list of type IDs and its associated struct btf */
+struct bpf_core_cand_list {
+	struct bpf_core_cand *cands;
+	int len;
+};
+
+#define BPF_CORE_SPEC_MAX_LEN 64
+
+/* represents BPF CO-RE field or array element accessor */
+struct bpf_core_accessor {
+	__u32 type_id;		/* struct/union type or array element type */
+	__u32 idx;		/* field index or array index */
+	const char *name;	/* field name or NULL for array accessor */
+};
+
+struct bpf_core_spec {
+	const struct btf *btf;
+	/* high-level spec: named fields and array indices only */
+	struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
+	/* original unresolved (no skip_mods_or_typedefs) root type ID */
+	__u32 root_type_id;
+	/* CO-RE relocation kind */
+	enum bpf_core_relo_kind relo_kind;
+	/* high-level spec length */
+	int len;
+	/* raw, low-level spec: 1-to-1 with accessor spec string */
+	int raw_spec[BPF_CORE_SPEC_MAX_LEN];
+	/* raw spec length */
+	int raw_len;
+	/* field bit offset represented by spec */
+	__u32 bit_offset;
+};
+
+struct bpf_core_relo_res {
+	/* expected value in the instruction, unless validate == false */
+	__u64 orig_val;
+	/* new value that needs to be patched up to */
+	__u64 new_val;
+	/* relocation unsuccessful, poison instruction, but don't fail load */
+	bool poison;
+	/* some relocations can't be validated against orig_val */
+	bool validate;
+	/* for field byte offset relocations or the forms:
+	 *     *(T *)(rX + <off>) = rY
+	 *     rX = *(T *)(rY + <off>),
+	 * we remember original and resolved field size to adjust direct
+	 * memory loads of pointers and integers; this is necessary for 32-bit
+	 * host kernel architectures, but also allows to automatically
+	 * relocate fields that were resized from, e.g., u32 to u64, etc.
+	 */
+	bool fail_memsz_adjust;
+	__u32 orig_sz;
+	__u32 orig_type_id;
+	__u32 new_sz;
+	__u32 new_type_id;
+};
+
+int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
+				const struct btf *targ_btf, __u32 targ_id, int level);
+int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
+			      const struct btf *targ_btf, __u32 targ_id);
+int __bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
+			   __u32 targ_id, bool behind_ptr, int level);
+int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf,
+			 __u32 targ_id);
+
+size_t bpf_core_essential_name_len(const char *name);
+
+int bpf_core_calc_relo_insn(const char *prog_name,
+			    const struct bpf_core_relo *relo, int relo_idx,
+			    const struct btf *local_btf,
+			    struct bpf_core_cand_list *cands,
+			    struct bpf_core_spec *specs_scratch,
+			    struct bpf_core_relo_res *targ_res);
+
+int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
+			int insn_idx, const struct bpf_core_relo *relo,
+			int relo_idx, const struct bpf_core_relo_res *res);
+
+int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
+		        const struct bpf_core_relo *relo,
+		        struct bpf_core_spec *spec);
+
+int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec);
+
+#endif
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
new file mode 100644
index 000000000..c8fe57401
--- /dev/null
+++ b/tools/lib/bpf/ringbuf.c
@@ -0,0 +1,684 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/*
+ * Ring buffer operations.
+ *
+ * Copyright (C) 2020 Facebook, Inc.
+ */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <linux/err.h>
+#include <linux/bpf.h>
+#include <asm/barrier.h>
+#include <sys/mman.h>
+#include <sys/epoll.h>
+#include <time.h>
+
+#include "libbpf.h"
+#include "libbpf_internal.h"
+#include "bpf.h"
+
+struct ring {
+	ring_buffer_sample_fn sample_cb;
+	void *ctx;
+	void *data;
+	unsigned long *consumer_pos;
+	unsigned long *producer_pos;
+	unsigned long mask;
+	int map_fd;
+};
+
+struct ring_buffer {
+	struct epoll_event *events;
+	struct ring **rings;
+	size_t page_size;
+	int epoll_fd;
+	int ring_cnt;
+};
+
+struct user_ring_buffer {
+	struct epoll_event event;
+	unsigned long *consumer_pos;
+	unsigned long *producer_pos;
+	void *data;
+	unsigned long mask;
+	size_t page_size;
+	int map_fd;
+	int epoll_fd;
+};
+
+/* 8-byte ring buffer header structure */
+struct ringbuf_hdr {
+	__u32 len;
+	__u32 pad;
+};
+
+static void ringbuf_free_ring(struct ring_buffer *rb, struct ring *r)
+{
+	if (r->consumer_pos) {
+		munmap(r->consumer_pos, rb->page_size);
+		r->consumer_pos = NULL;
+	}
+	if (r->producer_pos) {
+		munmap(r->producer_pos, rb->page_size + 2 * (r->mask + 1));
+		r->producer_pos = NULL;
+	}
+
+	free(r);
+}
+
+/* Add extra RINGBUF maps to this ring buffer manager */
+int ring_buffer__add(struct ring_buffer *rb, int map_fd,
+		     ring_buffer_sample_fn sample_cb, void *ctx)
+{
+	struct bpf_map_info info;
+	__u32 len = sizeof(info);
+	struct epoll_event *e;
+	struct ring *r;
+	__u64 mmap_sz;
+	void *tmp;
+	int err;
+
+	memset(&info, 0, sizeof(info));
+
+	err = bpf_map_get_info_by_fd(map_fd, &info, &len);
+	if (err) {
+		err = -errno;
+		pr_warn("ringbuf: failed to get map info for fd=%d: %s\n",
+			map_fd, errstr(err));
+		return libbpf_err(err);
+	}
+
+	if (info.type != BPF_MAP_TYPE_RINGBUF) {
+		pr_warn("ringbuf: map fd=%d is not BPF_MAP_TYPE_RINGBUF\n",
+			map_fd);
+		return libbpf_err(-EINVAL);
+	}
+
+	tmp = libbpf_reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings));
+	if (!tmp)
+		return libbpf_err(-ENOMEM);
+	rb->rings = tmp;
+
+	tmp = libbpf_reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events));
+	if (!tmp)
+		return libbpf_err(-ENOMEM);
+	rb->events = tmp;
+
+	r = calloc(1, sizeof(*r));
+	if (!r)
+		return libbpf_err(-ENOMEM);
+	rb->rings[rb->ring_cnt] = r;
+
+	r->map_fd = map_fd;
+	r->sample_cb = sample_cb;
+	r->ctx = ctx;
+	r->mask = info.max_entries - 1;
+
+	/* Map writable consumer page */
+	tmp = mmap(NULL, rb->page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0);
+	if (tmp == MAP_FAILED) {
+		err = -errno;
+		pr_warn("ringbuf: failed to mmap consumer page for map fd=%d: %s\n",
+			map_fd, errstr(err));
+		goto err_out;
+	}
+	r->consumer_pos = tmp;
+
+	/* Map read-only producer page and data pages. We map twice as big
+	 * data size to allow simple reading of samples that wrap around the
+	 * end of a ring buffer. See kernel implementation for details.
+	 */
+	mmap_sz = rb->page_size + 2 * (__u64)info.max_entries;
+	if (mmap_sz != (__u64)(size_t)mmap_sz) {
+		err = -E2BIG;
+		pr_warn("ringbuf: ring buffer size (%u) is too big\n", info.max_entries);
+		goto err_out;
+	}
+	tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ, MAP_SHARED, map_fd, rb->page_size);
+	if (tmp == MAP_FAILED) {
+		err = -errno;
+		pr_warn("ringbuf: failed to mmap data pages for map fd=%d: %s\n",
+			map_fd, errstr(err));
+		goto err_out;
+	}
+	r->producer_pos = tmp;
+	r->data = tmp + rb->page_size;
+
+	e = &rb->events[rb->ring_cnt];
+	memset(e, 0, sizeof(*e));
+
+	e->events = EPOLLIN;
+	e->data.fd = rb->ring_cnt;
+	if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, e) < 0) {
+		err = -errno;
+		pr_warn("ringbuf: failed to epoll add map fd=%d: %s\n",
+			map_fd, errstr(err));
+		goto err_out;
+	}
+
+	rb->ring_cnt++;
+	return 0;
+
+err_out:
+	ringbuf_free_ring(rb, r);
+	return libbpf_err(err);
+}
+
+void ring_buffer__free(struct ring_buffer *rb)
+{
+	int i;
+
+	if (!rb)
+		return;
+
+	for (i = 0; i < rb->ring_cnt; ++i)
+		ringbuf_free_ring(rb, rb->rings[i]);
+	if (rb->epoll_fd >= 0)
+		close(rb->epoll_fd);
+
+	free(rb->events);
+	free(rb->rings);
+	free(rb);
+}
+
+struct ring_buffer *
+ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx,
+		 const struct ring_buffer_opts *opts)
+{
+	struct ring_buffer *rb;
+	int err;
+
+	if (!OPTS_VALID(opts, ring_buffer_opts))
+		return errno = EINVAL, NULL;
+
+	rb = calloc(1, sizeof(*rb));
+	if (!rb)
+		return errno = ENOMEM, NULL;
+
+	rb->page_size = getpagesize();
+
+	rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+	if (rb->epoll_fd < 0) {
+		err = -errno;
+		pr_warn("ringbuf: failed to create epoll instance: %s\n", errstr(err));
+		goto err_out;
+	}
+
+	err = ring_buffer__add(rb, map_fd, sample_cb, ctx);
+	if (err)
+		goto err_out;
+
+	return rb;
+
+err_out:
+	ring_buffer__free(rb);
+	return errno = -err, NULL;
+}
+
+static inline int roundup_len(__u32 len)
+{
+	/* clear out top 2 bits (discard and busy, if set) */
+	len <<= 2;
+	len >>= 2;
+	/* add length prefix */
+	len += BPF_RINGBUF_HDR_SZ;
+	/* round up to 8 byte alignment */
+	return (len + 7) / 8 * 8;
+}
+
+static int64_t ringbuf_process_ring(struct ring *r, size_t n)
+{
+	int *len_ptr, len, err;
+	/* 64-bit to avoid overflow in case of extreme application behavior */
+	int64_t cnt = 0;
+	unsigned long cons_pos, prod_pos;
+	bool got_new_data;
+	void *sample;
+
+	cons_pos = smp_load_acquire(r->consumer_pos);
+	do {
+		got_new_data = false;
+		prod_pos = smp_load_acquire(r->producer_pos);
+		while (prod_pos - cons_pos > 0) {
+			len_ptr = r->data + (cons_pos & r->mask);
+			len = smp_load_acquire(len_ptr);
+
+			/* sample not committed yet, bail out for now */
+			if (len & BPF_RINGBUF_BUSY_BIT)
+				goto done;
+
+			got_new_data = true;
+			cons_pos += roundup_len(len);
+
+			if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) {
+				sample = (void *)len_ptr + BPF_RINGBUF_HDR_SZ;
+				err = r->sample_cb(r->ctx, sample, len);
+				if (err < 0) {
+					/* update consumer pos and bail out */
+					smp_store_release(r->consumer_pos,
+							  cons_pos);
+					return err;
+				}
+				cnt++;
+			}
+
+			smp_store_release(r->consumer_pos, cons_pos);
+
+			if (cnt >= n)
+				goto done;
+		}
+	} while (got_new_data);
+done:
+	return cnt;
+}
+
+/* Consume available ring buffer(s) data without event polling, up to n
+ * records.
+ *
+ * Returns number of records consumed across all registered ring buffers (or
+ * n, whichever is less), or negative number if any of the callbacks return
+ * error.
+ */
+int ring_buffer__consume_n(struct ring_buffer *rb, size_t n)
+{
+	int64_t err, res = 0;
+	int i;
+
+	for (i = 0; i < rb->ring_cnt; i++) {
+		struct ring *ring = rb->rings[i];
+
+		err = ringbuf_process_ring(ring, n);
+		if (err < 0)
+			return libbpf_err(err);
+		res += err;
+		n -= err;
+
+		if (n == 0)
+			break;
+	}
+	return res > INT_MAX ? INT_MAX : res;
+}
+
+/* Consume available ring buffer(s) data without event polling.
+ * Returns number of records consumed across all registered ring buffers (or
+ * INT_MAX, whichever is less), or negative number if any of the callbacks
+ * return error.
+ */
+int ring_buffer__consume(struct ring_buffer *rb)
+{
+	int64_t err, res = 0;
+	int i;
+
+	for (i = 0; i < rb->ring_cnt; i++) {
+		struct ring *ring = rb->rings[i];
+
+		err = ringbuf_process_ring(ring, INT_MAX);
+		if (err < 0)
+			return libbpf_err(err);
+		res += err;
+		if (res > INT_MAX) {
+			res = INT_MAX;
+			break;
+		}
+	}
+	return res;
+}
+
+/* Poll for available data and consume records, if any are available.
+ * Returns number of records consumed (or INT_MAX, whichever is less), or
+ * negative number, if any of the registered callbacks returned error.
+ */
+int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
+{
+	int i, cnt;
+	int64_t err, res = 0;
+
+	cnt = epoll_wait(rb->epoll_fd, rb->events, rb->ring_cnt, timeout_ms);
+	if (cnt < 0)
+		return libbpf_err(-errno);
+
+	for (i = 0; i < cnt; i++) {
+		__u32 ring_id = rb->events[i].data.fd;
+		struct ring *ring = rb->rings[ring_id];
+
+		err = ringbuf_process_ring(ring, INT_MAX);
+		if (err < 0)
+			return libbpf_err(err);
+		res += err;
+	}
+	if (res > INT_MAX)
+		res = INT_MAX;
+	return res;
+}
+
+/* Get an fd that can be used to sleep until data is available in the ring(s) */
+int ring_buffer__epoll_fd(const struct ring_buffer *rb)
+{
+	return rb->epoll_fd;
+}
+
+struct ring *ring_buffer__ring(struct ring_buffer *rb, unsigned int idx)
+{
+	if (idx >= rb->ring_cnt)
+		return errno = ERANGE, NULL;
+
+	return rb->rings[idx];
+}
+
+unsigned long ring__consumer_pos(const struct ring *r)
+{
+	/* Synchronizes with smp_store_release() in ringbuf_process_ring(). */
+	return smp_load_acquire(r->consumer_pos);
+}
+
+unsigned long ring__producer_pos(const struct ring *r)
+{
+	/* Synchronizes with smp_store_release() in __bpf_ringbuf_reserve() in
+	 * the kernel.
+	 */
+	return smp_load_acquire(r->producer_pos);
+}
+
+size_t ring__avail_data_size(const struct ring *r)
+{
+	unsigned long cons_pos, prod_pos;
+
+	cons_pos = ring__consumer_pos(r);
+	prod_pos = ring__producer_pos(r);
+	return prod_pos - cons_pos;
+}
+
+size_t ring__size(const struct ring *r)
+{
+	return r->mask + 1;
+}
+
+int ring__map_fd(const struct ring *r)
+{
+	return r->map_fd;
+}
+
+int ring__consume_n(struct ring *r, size_t n)
+{
+	int64_t res;
+
+	res = ringbuf_process_ring(r, n);
+	if (res < 0)
+		return libbpf_err(res);
+
+	return res > INT_MAX ? INT_MAX : res;
+}
+
+int ring__consume(struct ring *r)
+{
+	return ring__consume_n(r, INT_MAX);
+}
+
+static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
+{
+	if (rb->consumer_pos) {
+		munmap(rb->consumer_pos, rb->page_size);
+		rb->consumer_pos = NULL;
+	}
+	if (rb->producer_pos) {
+		munmap(rb->producer_pos, rb->page_size + 2 * (rb->mask + 1));
+		rb->producer_pos = NULL;
+	}
+}
+
+void user_ring_buffer__free(struct user_ring_buffer *rb)
+{
+	if (!rb)
+		return;
+
+	user_ringbuf_unmap_ring(rb);
+
+	if (rb->epoll_fd >= 0)
+		close(rb->epoll_fd);
+
+	free(rb);
+}
+
+static int user_ringbuf_map(struct user_ring_buffer *rb, int map_fd)
+{
+	struct bpf_map_info info;
+	__u32 len = sizeof(info);
+	__u64 mmap_sz;
+	void *tmp;
+	struct epoll_event *rb_epoll;
+	int err;
+
+	memset(&info, 0, sizeof(info));
+
+	err = bpf_map_get_info_by_fd(map_fd, &info, &len);
+	if (err) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to get map info for fd=%d: %s\n",
+			map_fd, errstr(err));
+		return err;
+	}
+
+	if (info.type != BPF_MAP_TYPE_USER_RINGBUF) {
+		pr_warn("user ringbuf: map fd=%d is not BPF_MAP_TYPE_USER_RINGBUF\n", map_fd);
+		return -EINVAL;
+	}
+
+	rb->map_fd = map_fd;
+	rb->mask = info.max_entries - 1;
+
+	/* Map read-only consumer page */
+	tmp = mmap(NULL, rb->page_size, PROT_READ, MAP_SHARED, map_fd, 0);
+	if (tmp == MAP_FAILED) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to mmap consumer page for map fd=%d: %s\n",
+			map_fd, errstr(err));
+		return err;
+	}
+	rb->consumer_pos = tmp;
+
+	/* Map read-write the producer page and data pages. We map the data
+	 * region as twice the total size of the ring buffer to allow the
+	 * simple reading and writing of samples that wrap around the end of
+	 * the buffer.  See the kernel implementation for details.
+	 */
+	mmap_sz = rb->page_size + 2 * (__u64)info.max_entries;
+	if (mmap_sz != (__u64)(size_t)mmap_sz) {
+		pr_warn("user ringbuf: ring buf size (%u) is too big\n", info.max_entries);
+		return -E2BIG;
+	}
+	tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED,
+		   map_fd, rb->page_size);
+	if (tmp == MAP_FAILED) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to mmap data pages for map fd=%d: %s\n",
+			map_fd, errstr(err));
+		return err;
+	}
+
+	rb->producer_pos = tmp;
+	rb->data = tmp + rb->page_size;
+
+	rb_epoll = &rb->event;
+	rb_epoll->events = EPOLLOUT;
+	if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, rb_epoll) < 0) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to epoll add map fd=%d: %s\n", map_fd, errstr(err));
+		return err;
+	}
+
+	return 0;
+}
+
+struct user_ring_buffer *
+user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts)
+{
+	struct user_ring_buffer *rb;
+	int err;
+
+	if (!OPTS_VALID(opts, user_ring_buffer_opts))
+		return errno = EINVAL, NULL;
+
+	rb = calloc(1, sizeof(*rb));
+	if (!rb)
+		return errno = ENOMEM, NULL;
+
+	rb->page_size = getpagesize();
+
+	rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+	if (rb->epoll_fd < 0) {
+		err = -errno;
+		pr_warn("user ringbuf: failed to create epoll instance: %s\n", errstr(err));
+		goto err_out;
+	}
+
+	err = user_ringbuf_map(rb, map_fd);
+	if (err)
+		goto err_out;
+
+	return rb;
+
+err_out:
+	user_ring_buffer__free(rb);
+	return errno = -err, NULL;
+}
+
+static void user_ringbuf_commit(struct user_ring_buffer *rb, void *sample, bool discard)
+{
+	__u32 new_len;
+	struct ringbuf_hdr *hdr;
+	uintptr_t hdr_offset;
+
+	hdr_offset = rb->mask + 1 + (sample - rb->data) - BPF_RINGBUF_HDR_SZ;
+	hdr = rb->data + (hdr_offset & rb->mask);
+
+	new_len = hdr->len & ~BPF_RINGBUF_BUSY_BIT;
+	if (discard)
+		new_len |= BPF_RINGBUF_DISCARD_BIT;
+
+	/* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in
+	 * the kernel.
+	 */
+	__atomic_exchange_n(&hdr->len, new_len, __ATOMIC_ACQ_REL);
+}
+
+void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample)
+{
+	user_ringbuf_commit(rb, sample, true);
+}
+
+void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample)
+{
+	user_ringbuf_commit(rb, sample, false);
+}
+
+void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size)
+{
+	__u32 avail_size, total_size, max_size;
+	/* 64-bit to avoid overflow in case of extreme application behavior */
+	__u64 cons_pos, prod_pos;
+	struct ringbuf_hdr *hdr;
+
+	/* The top two bits are used as special flags */
+	if (size & (BPF_RINGBUF_BUSY_BIT | BPF_RINGBUF_DISCARD_BIT))
+		return errno = E2BIG, NULL;
+
+	/* Synchronizes with smp_store_release() in __bpf_user_ringbuf_peek() in
+	 * the kernel.
+	 */
+	cons_pos = smp_load_acquire(rb->consumer_pos);
+	/* Synchronizes with smp_store_release() in user_ringbuf_commit() */
+	prod_pos = smp_load_acquire(rb->producer_pos);
+
+	max_size = rb->mask + 1;
+	avail_size = max_size - (prod_pos - cons_pos);
+	/* Round up total size to a multiple of 8. */
+	total_size = (size + BPF_RINGBUF_HDR_SZ + 7) / 8 * 8;
+
+	if (total_size > max_size)
+		return errno = E2BIG, NULL;
+
+	if (avail_size < total_size)
+		return errno = ENOSPC, NULL;
+
+	hdr = rb->data + (prod_pos & rb->mask);
+	hdr->len = size | BPF_RINGBUF_BUSY_BIT;
+	hdr->pad = 0;
+
+	/* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in
+	 * the kernel.
+	 */
+	smp_store_release(rb->producer_pos, prod_pos + total_size);
+
+	return (void *)rb->data + ((prod_pos + BPF_RINGBUF_HDR_SZ) & rb->mask);
+}
+
+static __u64 ns_elapsed_timespec(const struct timespec *start, const struct timespec *end)
+{
+	__u64 start_ns, end_ns, ns_per_s = 1000000000;
+
+	start_ns = (__u64)start->tv_sec * ns_per_s + start->tv_nsec;
+	end_ns = (__u64)end->tv_sec * ns_per_s + end->tv_nsec;
+
+	return end_ns - start_ns;
+}
+
+void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms)
+{
+	void *sample;
+	int err, ms_remaining = timeout_ms;
+	struct timespec start;
+
+	if (timeout_ms < 0 && timeout_ms != -1)
+		return errno = EINVAL, NULL;
+
+	if (timeout_ms != -1) {
+		err = clock_gettime(CLOCK_MONOTONIC, &start);
+		if (err)
+			return NULL;
+	}
+
+	do {
+		int cnt, ms_elapsed;
+		struct timespec curr;
+		__u64 ns_per_ms = 1000000;
+
+		sample = user_ring_buffer__reserve(rb, size);
+		if (sample)
+			return sample;
+		else if (errno != ENOSPC)
+			return NULL;
+
+		/* The kernel guarantees at least one event notification
+		 * delivery whenever at least one sample is drained from the
+		 * ring buffer in an invocation to bpf_ringbuf_drain(). Other
+		 * additional events may be delivered at any time, but only one
+		 * event is guaranteed per bpf_ringbuf_drain() invocation,
+		 * provided that a sample is drained, and the BPF program did
+		 * not pass BPF_RB_NO_WAKEUP to bpf_ringbuf_drain(). If
+		 * BPF_RB_FORCE_WAKEUP is passed to bpf_ringbuf_drain(), a
+		 * wakeup event will be delivered even if no samples are
+		 * drained.
+		 */
+		cnt = epoll_wait(rb->epoll_fd, &rb->event, 1, ms_remaining);
+		if (cnt < 0)
+			return NULL;
+
+		if (timeout_ms == -1)
+			continue;
+
+		err = clock_gettime(CLOCK_MONOTONIC, &curr);
+		if (err)
+			return NULL;
+
+		ms_elapsed = ns_elapsed_timespec(&start, &curr) / ns_per_ms;
+		ms_remaining = timeout_ms - ms_elapsed;
+	} while (ms_remaining > 0);
+
+	/* Try one more time to reserve a sample after the specified timeout has elapsed. */
+	return user_ring_buffer__reserve(rb, size);
+}
diff --git a/tools/lib/bpf/skel_internal.h b/tools/lib/bpf/skel_internal.h
new file mode 100644
index 000000000..1f3f332df
--- /dev/null
+++ b/tools/lib/bpf/skel_internal.h
@@ -0,0 +1,441 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (c) 2021 Facebook */
+#ifndef __SKEL_INTERNAL_H
+#define __SKEL_INTERNAL_H
+
+#ifdef __KERNEL__
+#include <linux/fdtable.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#else
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <linux/keyctl.h>
+#include <stdlib.h>
+#include "bpf.h"
+#endif
+
+#ifndef __NR_bpf
+# if defined(__mips__) && defined(_ABIO32)
+#  define __NR_bpf 4355
+# elif defined(__mips__) && defined(_ABIN32)
+#  define __NR_bpf 6319
+# elif defined(__mips__) && defined(_ABI64)
+#  define __NR_bpf 5315
+# endif
+#endif
+
+/* This file is a base header for auto-generated *.lskel.h files.
+ * Its contents will change and may become part of auto-generation in the future.
+ *
+ * The layout of bpf_[map|prog]_desc and bpf_loader_ctx is feature dependent
+ * and will change from one version of libbpf to another and features
+ * requested during loader program generation.
+ */
+struct bpf_map_desc {
+	/* output of the loader prog */
+	int map_fd;
+	/* input for the loader prog */
+	__u32 max_entries;
+	__aligned_u64 initial_value;
+};
+struct bpf_prog_desc {
+	int prog_fd;
+};
+
+enum {
+	BPF_SKEL_KERNEL = (1ULL << 0),
+};
+
+struct bpf_loader_ctx {
+	__u32 sz;
+	__u32 flags;
+	__u32 log_level;
+	__u32 log_size;
+	__u64 log_buf;
+};
+
+struct bpf_load_and_run_opts {
+	struct bpf_loader_ctx *ctx;
+	const void *data;
+	const void *insns;
+	__u32 data_sz;
+	__u32 insns_sz;
+	const char *errstr;
+	void *signature;
+	__u32 signature_sz;
+	__s32 keyring_id;
+	void *excl_prog_hash;
+	__u32 excl_prog_hash_sz;
+};
+
+long kern_sys_bpf(__u32 cmd, void *attr, __u32 attr_size);
+
+static inline int skel_sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
+			  unsigned int size)
+{
+#ifdef __KERNEL__
+	return kern_sys_bpf(cmd, attr, size);
+#else
+	return syscall(__NR_bpf, cmd, attr, size);
+#endif
+}
+
+#ifdef __KERNEL__
+static inline int close(int fd)
+{
+	return close_fd(fd);
+}
+
+static inline void *skel_alloc(size_t size)
+{
+	struct bpf_loader_ctx *ctx = kzalloc(size, GFP_KERNEL);
+
+	if (!ctx)
+		return NULL;
+	ctx->flags |= BPF_SKEL_KERNEL;
+	return ctx;
+}
+
+static inline void skel_free(const void *p)
+{
+	kfree(p);
+}
+
+/* skel->bss/rodata maps are populated the following way:
+ *
+ * For kernel use:
+ * skel_prep_map_data() allocates kernel memory that kernel module can directly access.
+ * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
+ * The loader program will perform probe_read_kernel() from maps.rodata.initial_value.
+ * skel_finalize_map_data() sets skel->rodata to point to actual value in a bpf map and
+ * does maps.rodata.initial_value = ~0ULL to signal skel_free_map_data() that kvfree
+ * is not necessary.
+ *
+ * For user space:
+ * skel_prep_map_data() mmaps anon memory into skel->rodata that can be accessed directly.
+ * Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
+ * The loader program will perform copy_from_user() from maps.rodata.initial_value.
+ * skel_finalize_map_data() remaps bpf array map value from the kernel memory into
+ * skel->rodata address.
+ *
+ * The "bpftool gen skeleton -L" command generates lskel.h that is suitable for
+ * both kernel and user space. The generated loader program does
+ * either bpf_probe_read_kernel() or bpf_copy_from_user() from initial_value
+ * depending on bpf_loader_ctx->flags.
+ */
+static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
+{
+	if (addr != ~0ULL)
+		kvfree(p);
+	/*
+	 * When addr == ~0ULL the init buffer has already been released.
+	 * For skel_finalize_map_data(), 'p' points to
+	 * ((struct bpf_array *)map)->value.
+	 */
+}
+
+static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
+{
+	void *addr;
+
+	addr = kvmalloc(val_sz, GFP_KERNEL);
+	if (!addr)
+		return NULL;
+	memcpy(addr, val, val_sz);
+	return addr;
+}
+
+static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
+{
+	struct bpf_map *map;
+	void *addr = NULL;
+
+	kvfree((void *) (long) *init_val);
+	*init_val = ~0ULL;
+
+	/* At this point bpf_load_and_run() finished without error and
+	 * 'fd' is a valid bpf map FD. All sanity checks below should succeed.
+	 */
+	map = bpf_map_get(fd);
+	if (IS_ERR(map))
+		return NULL;
+	if (map->map_type != BPF_MAP_TYPE_ARRAY)
+		goto out;
+	addr = ((struct bpf_array *)map)->value;
+	/* the addr stays valid, since FD is not closed */
+out:
+	bpf_map_put(map);
+	return addr;
+}
+
+static inline int skel_protect_map_data(void *p, __u64 *init_val, size_t sz)
+{
+	(void)sz;
+
+	kvfree(p);
+	*init_val = ~0ULL;
+	return 0;
+}
+
+#else
+
+static inline void *skel_alloc(size_t size)
+{
+	return calloc(1, size);
+}
+
+static inline void skel_free(void *p)
+{
+	free(p);
+}
+
+static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
+{
+	munmap(p, sz);
+}
+
+static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
+{
+	void *addr;
+
+	addr = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
+		    MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (addr == (void *) -1)
+		return NULL;
+	memcpy(addr, val, val_sz);
+	return addr;
+}
+
+static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
+{
+	void *addr;
+
+	addr = mmap((void *) (long) *init_val, mmap_sz, flags, MAP_SHARED | MAP_FIXED, fd, 0);
+	if (addr == (void *) -1)
+		return NULL;
+	return addr;
+}
+
+static inline int skel_protect_map_data(void *p, __u64 *init_val, size_t sz)
+{
+	(void)init_val;
+
+	if (mprotect(p, sz, PROT_READ))
+		return -errno;
+	return 0;
+}
+#endif
+
+static inline int skel_closenz(int fd)
+{
+	if (fd > 0)
+		return close(fd);
+	return -EINVAL;
+}
+
+#ifndef offsetofend
+#define offsetofend(TYPE, MEMBER) \
+	(offsetof(TYPE, MEMBER)	+ sizeof((((TYPE *)0)->MEMBER)))
+#endif
+
+static inline int skel_map_create(enum bpf_map_type map_type,
+				  const char *map_name,
+				  __u32 key_size,
+				  __u32 value_size,
+				  __u32 max_entries,
+				  const void *excl_prog_hash,
+				  __u32 excl_prog_hash_sz)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, excl_prog_hash_size);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+
+	attr.map_type = map_type;
+	attr.excl_prog_hash = (unsigned long) excl_prog_hash;
+	attr.excl_prog_hash_size = excl_prog_hash_sz;
+
+#ifdef __KERNEL__
+	if (strscpy(attr.map_name, map_name) < 0)
+		return -EINVAL;
+#else
+	strncpy(attr.map_name, map_name, sizeof(attr.map_name));
+#endif
+	attr.key_size = key_size;
+	attr.value_size = value_size;
+	attr.max_entries = max_entries;
+
+	return skel_sys_bpf(BPF_MAP_CREATE, &attr, attr_sz);
+}
+
+static inline int skel_map_update_elem(int fd, const void *key,
+				       const void *value, __u64 flags)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = (long) key;
+	attr.value = (long) value;
+	attr.flags = flags;
+
+	return skel_sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, attr_sz);
+}
+
+static inline int skel_map_delete_elem(int fd, const void *key)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+	attr.key = (long)key;
+
+	return skel_sys_bpf(BPF_MAP_DELETE_ELEM, &attr, attr_sz);
+}
+
+static inline int skel_map_get_fd_by_id(__u32 id)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, flags);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_id = id;
+
+	return skel_sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz);
+}
+
+static inline int skel_raw_tracepoint_open(const char *name, int prog_fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, raw_tracepoint.prog_fd);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.raw_tracepoint.name = (long) name;
+	attr.raw_tracepoint.prog_fd = prog_fd;
+
+	return skel_sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, attr_sz);
+}
+
+static inline int skel_link_create(int prog_fd, int target_fd,
+				   enum bpf_attach_type attach_type)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, link_create.iter_info_len);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.link_create.prog_fd = prog_fd;
+	attr.link_create.target_fd = target_fd;
+	attr.link_create.attach_type = attach_type;
+
+	return skel_sys_bpf(BPF_LINK_CREATE, &attr, attr_sz);
+}
+
+static inline int skel_map_freeze(int fd)
+{
+	const size_t attr_sz = offsetofend(union bpf_attr, map_fd);
+	union bpf_attr attr;
+
+	memset(&attr, 0, attr_sz);
+	attr.map_fd = fd;
+
+	return skel_sys_bpf(BPF_MAP_FREEZE, &attr, attr_sz);
+}
+#ifdef __KERNEL__
+#define set_err
+#else
+#define set_err err = -errno
+#endif
+
+static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
+{
+	const size_t prog_load_attr_sz = offsetofend(union bpf_attr, keyring_id);
+	const size_t test_run_attr_sz = offsetofend(union bpf_attr, test);
+	int map_fd = -1, prog_fd = -1, key = 0, err;
+	union bpf_attr attr;
+
+	err = map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1,
+				       opts->excl_prog_hash, opts->excl_prog_hash_sz);
+	if (map_fd < 0) {
+		opts->errstr = "failed to create loader map";
+		set_err;
+		goto out;
+	}
+
+	err = skel_map_update_elem(map_fd, &key, opts->data, 0);
+	if (err < 0) {
+		opts->errstr = "failed to update loader map";
+		set_err;
+		goto out;
+	}
+
+#ifndef __KERNEL__
+	err = skel_map_freeze(map_fd);
+	if (err < 0) {
+		opts->errstr = "failed to freeze map";
+		set_err;
+		goto out;
+	}
+#endif
+
+	memset(&attr, 0, prog_load_attr_sz);
+	attr.prog_type = BPF_PROG_TYPE_SYSCALL;
+	attr.insns = (long) opts->insns;
+	attr.insn_cnt = opts->insns_sz / sizeof(struct bpf_insn);
+	attr.license = (long) "Dual BSD/GPL";
+#ifndef __KERNEL__
+	attr.signature = (long) opts->signature;
+	attr.signature_size = opts->signature_sz;
+	if (opts->signature)
+		attr.fd_array_cnt = 1;
+#else
+	if (opts->signature || opts->signature_sz)
+		pr_warn("signatures are not supported from bpf_preload\n");
+#endif
+	attr.keyring_id = opts->keyring_id;
+	memcpy(attr.prog_name, "__loader.prog", sizeof("__loader.prog"));
+	attr.fd_array = (long) &map_fd;
+	attr.log_level = opts->ctx->log_level;
+	attr.log_size = opts->ctx->log_size;
+	attr.log_buf = opts->ctx->log_buf;
+	attr.prog_flags = BPF_F_SLEEPABLE;
+	err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, prog_load_attr_sz);
+	if (prog_fd < 0) {
+		opts->errstr = "failed to load loader prog";
+		set_err;
+		goto out;
+	}
+
+	memset(&attr, 0, test_run_attr_sz);
+	attr.test.prog_fd = prog_fd;
+	attr.test.ctx_in = (long) opts->ctx;
+	attr.test.ctx_size_in = opts->ctx->sz;
+	err = skel_sys_bpf(BPF_PROG_RUN, &attr, test_run_attr_sz);
+	if (err < 0 || (int)attr.test.retval < 0) {
+		if (err < 0) {
+			opts->errstr = "failed to execute loader prog";
+			set_err;
+		} else {
+			opts->errstr = "error returned by loader prog";
+			err = (int)attr.test.retval;
+#ifndef __KERNEL__
+			errno = -err;
+#endif
+		}
+		goto out;
+	}
+	err = 0;
+out:
+	if (map_fd >= 0)
+		close(map_fd);
+	if (prog_fd >= 0)
+		close(prog_fd);
+	return err;
+}
+
+#endif
diff --git a/tools/lib/bpf/strset.c b/tools/lib/bpf/strset.c
new file mode 100644
index 000000000..ace73c6b3
--- /dev/null
+++ b/tools/lib/bpf/strset.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2021 Facebook */
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <linux/err.h>
+#include "hashmap.h"
+#include "libbpf_internal.h"
+#include "strset.h"
+
+struct strset {
+	void *strs_data;
+	size_t strs_data_len;
+	size_t strs_data_cap;
+	size_t strs_data_max_len;
+
+	/* lookup index for each unique string in strings set */
+	struct hashmap *strs_hash;
+};
+
+static size_t strset_hash_fn(long key, void *ctx)
+{
+	const struct strset *s = ctx;
+	const char *str = s->strs_data + key;
+
+	return str_hash(str);
+}
+
+static bool strset_equal_fn(long key1, long key2, void *ctx)
+{
+	const struct strset *s = ctx;
+	const char *str1 = s->strs_data + key1;
+	const char *str2 = s->strs_data + key2;
+
+	return strcmp(str1, str2) == 0;
+}
+
+struct strset *strset__new(size_t max_data_sz, const char *init_data, size_t init_data_sz)
+{
+	struct strset *set = calloc(1, sizeof(*set));
+	struct hashmap *hash;
+	int err = -ENOMEM;
+
+	if (!set)
+		return ERR_PTR(-ENOMEM);
+
+	hash = hashmap__new(strset_hash_fn, strset_equal_fn, set);
+	if (IS_ERR(hash))
+		goto err_out;
+
+	set->strs_data_max_len = max_data_sz;
+	set->strs_hash = hash;
+
+	if (init_data) {
+		long off;
+
+		set->strs_data = malloc(init_data_sz);
+		if (!set->strs_data)
+			goto err_out;
+
+		memcpy(set->strs_data, init_data, init_data_sz);
+		set->strs_data_len = init_data_sz;
+		set->strs_data_cap = init_data_sz;
+
+		for (off = 0; off < set->strs_data_len; off += strlen(set->strs_data + off) + 1) {
+			/* hashmap__add() returns EEXIST if string with the same
+			 * content already is in the hash map
+			 */
+			err = hashmap__add(hash, off, off);
+			if (err == -EEXIST)
+				continue; /* duplicate */
+			if (err)
+				goto err_out;
+		}
+	}
+
+	return set;
+err_out:
+	strset__free(set);
+	return ERR_PTR(err);
+}
+
+void strset__free(struct strset *set)
+{
+	if (IS_ERR_OR_NULL(set))
+		return;
+
+	hashmap__free(set->strs_hash);
+	free(set->strs_data);
+	free(set);
+}
+
+size_t strset__data_size(const struct strset *set)
+{
+	return set->strs_data_len;
+}
+
+const char *strset__data(const struct strset *set)
+{
+	return set->strs_data;
+}
+
+static void *strset_add_str_mem(struct strset *set, size_t add_sz)
+{
+	return libbpf_add_mem(&set->strs_data, &set->strs_data_cap, 1,
+			      set->strs_data_len, set->strs_data_max_len, add_sz);
+}
+
+static long strset_str_append(struct strset *set, const char *s)
+{
+	uintptr_t old_data = (uintptr_t)set->strs_data;
+	size_t old_data_len = set->strs_data_len;
+	uintptr_t old_s = (uintptr_t)s;
+	long len = strlen(s) + 1;
+	void *p;
+
+	/*
+	 * Hashmap keys are always offsets within set->strs_data, so to even
+	 * look up some string from the "outside", we need to first append it
+	 * at the end, so that it can be addressed with an offset. Luckily,
+	 * until set->strs_data_len is incremented, that string is just a piece
+	 * of garbage for the rest of the code, so no harm, no foul. On the
+	 * other hand, if the string is unique, it's already appended and
+	 * ready to be used, only a simple set->strs_data_len increment away.
+	 */
+	p = strset_add_str_mem(set, len);
+	if (!p)
+		return -ENOMEM;
+
+	/*
+	 * The set->strs_data might have reallocated and if 's' pointed
+	 * to an internal string within the old buffer, then it became
+	 * dangling and needs to be reconstructed before the copy.
+	 */
+	if (old_data && old_data != (uintptr_t)set->strs_data &&
+	    old_s >= old_data && old_s < old_data + old_data_len)
+		s = set->strs_data + (old_s - old_data);
+
+	memcpy(p, s, len);
+
+	return len;
+}
+
+/* Find string offset that corresponds to a given string *s*.
+ * Returns:
+ *   - >0 offset into string data, if string is found;
+ *   - -ENOENT, if string is not in the string data;
+ *   - <0, on any other error.
+ */
+int strset__find_str(struct strset *set, const char *s)
+{
+	long old_off, new_off, len;
+
+	len = strset_str_append(set, s);
+	if (len < 0)
+		return len;
+
+	new_off = set->strs_data_len;
+
+	if (hashmap__find(set->strs_hash, new_off, &old_off))
+		return old_off;
+
+	return -ENOENT;
+}
+
+/* Add a string s to the string data. If the string already exists, return its
+ * offset within string data.
+ * Returns:
+ *   - > 0 offset into string data, on success;
+ *   - < 0, on error.
+ */
+int strset__add_str(struct strset *set, const char *s)
+{
+	long old_off, new_off, len;
+	int err;
+
+	len = strset_str_append(set, s);
+	if (len < 0)
+		return len;
+
+	new_off = set->strs_data_len;
+
+	/* Now attempt to add the string, but only if the string with the same
+	 * contents doesn't exist already (HASHMAP_ADD strategy). If such
+	 * string exists, we'll get its offset in old_off (that's old_key).
+	 */
+	err = hashmap__insert(set->strs_hash, new_off, new_off,
+			      HASHMAP_ADD, &old_off, NULL);
+	if (err == -EEXIST)
+		return old_off; /* duplicated string, return existing offset */
+	if (err)
+		return err;
+
+	set->strs_data_len += len; /* new unique string, adjust data length */
+	return new_off;
+}
diff --git a/tools/lib/bpf/strset.h b/tools/lib/bpf/strset.h
new file mode 100644
index 000000000..b6ddf77a8
--- /dev/null
+++ b/tools/lib/bpf/strset.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+/* Copyright (c) 2021 Facebook */
+#ifndef __LIBBPF_STRSET_H
+#define __LIBBPF_STRSET_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+struct strset;
+
+struct strset *strset__new(size_t max_data_sz, const char *init_data, size_t init_data_sz);
+void strset__free(struct strset *set);
+
+const char *strset__data(const struct strset *set);
+size_t strset__data_size(const struct strset *set);
+
+int strset__find_str(struct strset *set, const char *s);
+int strset__add_str(struct strset *set, const char *s);
+
+#endif /* __LIBBPF_STRSET_H */
diff --git a/tools/lib/bpf/usdt.bpf.h b/tools/lib/bpf/usdt.bpf.h
new file mode 100644
index 000000000..43deb05a5
--- /dev/null
+++ b/tools/lib/bpf/usdt.bpf.h
@@ -0,0 +1,322 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+#ifndef __USDT_BPF_H__
+#define __USDT_BPF_H__
+
+#include <linux/errno.h>
+#include "bpf_helpers.h"
+#include "bpf_tracing.h"
+
+/* Below types and maps are internal implementation details of libbpf's USDT
+ * support and are subjects to change. Also, bpf_usdt_xxx() API helpers should
+ * be considered an unstable API as well and might be adjusted based on user
+ * feedback from using libbpf's USDT support in production.
+ */
+
+/* User can override BPF_USDT_MAX_SPEC_CNT to change default size of internal
+ * map that keeps track of USDT argument specifications. This might be
+ * necessary if there are a lot of USDT attachments.
+ */
+#ifndef BPF_USDT_MAX_SPEC_CNT
+#define BPF_USDT_MAX_SPEC_CNT 256
+#endif
+/* User can override BPF_USDT_MAX_IP_CNT to change default size of internal
+ * map that keeps track of IP (memory address) mapping to USDT argument
+ * specification.
+ * Note, if kernel supports BPF cookies, this map is not used and could be
+ * resized all the way to 1 to save a bit of memory.
+ */
+#ifndef BPF_USDT_MAX_IP_CNT
+#define BPF_USDT_MAX_IP_CNT (4 * BPF_USDT_MAX_SPEC_CNT)
+#endif
+
+enum __bpf_usdt_arg_type {
+	BPF_USDT_ARG_CONST,
+	BPF_USDT_ARG_REG,
+	BPF_USDT_ARG_REG_DEREF,
+	BPF_USDT_ARG_SIB,
+};
+
+/*
+ * This struct layout is designed specifically to be backwards/forward
+ * compatible between libbpf versions for ARG_CONST, ARG_REG, and
+ * ARG_REG_DEREF modes. ARG_SIB requires libbpf v1.7+.
+ */
+struct __bpf_usdt_arg_spec {
+	/* u64 scalar interpreted depending on arg_type, see below */
+	__u64 val_off;
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	/* arg location case, see bpf_usdt_arg() for details */
+	enum __bpf_usdt_arg_type arg_type: 8;
+	/* index register offset within struct pt_regs */
+	__u16 idx_reg_off: 12;
+	/* scale factor for index register (1, 2, 4, or 8) */
+	__u16 scale_bitshift: 4;
+	/* reserved for future use, keeps reg_off offset stable */
+	__u8 __reserved: 8;
+#else
+	__u8 __reserved: 8;
+	__u16 idx_reg_off: 12;
+	__u16 scale_bitshift: 4;
+	enum __bpf_usdt_arg_type arg_type: 8;
+#endif
+	/* offset of referenced register within struct pt_regs */
+	short reg_off;
+	/* whether arg should be interpreted as signed value */
+	bool arg_signed;
+	/* number of bits that need to be cleared and, optionally,
+	 * sign-extended to cast arguments that are 1, 2, or 4 bytes
+	 * long into final 8-byte u64/s64 value returned to user
+	 */
+	char arg_bitshift;
+};
+
+/* should match USDT_MAX_ARG_CNT in usdt.c exactly */
+#define BPF_USDT_MAX_ARG_CNT 12
+struct __bpf_usdt_spec {
+	struct __bpf_usdt_arg_spec args[BPF_USDT_MAX_ARG_CNT];
+	__u64 usdt_cookie;
+	short arg_cnt;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, BPF_USDT_MAX_SPEC_CNT);
+	__type(key, int);
+	__type(value, struct __bpf_usdt_spec);
+} __bpf_usdt_specs SEC(".maps") __weak;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, BPF_USDT_MAX_IP_CNT);
+	__type(key, long);
+	__type(value, __u32);
+} __bpf_usdt_ip_to_spec_id SEC(".maps") __weak;
+
+extern const _Bool LINUX_HAS_BPF_COOKIE __kconfig;
+
+static __always_inline
+int __bpf_usdt_spec_id(struct pt_regs *ctx)
+{
+	if (!LINUX_HAS_BPF_COOKIE) {
+		long ip = PT_REGS_IP(ctx);
+		int *spec_id_ptr;
+
+		spec_id_ptr = bpf_map_lookup_elem(&__bpf_usdt_ip_to_spec_id, &ip);
+		return spec_id_ptr ? *spec_id_ptr : -ESRCH;
+	}
+
+	return bpf_get_attach_cookie(ctx);
+}
+
+/* Return number of USDT arguments defined for currently traced USDT. */
+__weak __hidden
+int bpf_usdt_arg_cnt(struct pt_regs *ctx)
+{
+	struct __bpf_usdt_spec *spec;
+	int spec_id;
+
+	spec_id = __bpf_usdt_spec_id(ctx);
+	if (spec_id < 0)
+		return -ESRCH;
+
+	spec = bpf_map_lookup_elem(&__bpf_usdt_specs, &spec_id);
+	if (!spec)
+		return -ESRCH;
+
+	return spec->arg_cnt;
+}
+
+/* Returns the size in bytes of the #*arg_num* (zero-indexed) USDT argument.
+ * Returns negative error if argument is not found or arg_num is invalid.
+ */
+static __always_inline
+int bpf_usdt_arg_size(struct pt_regs *ctx, __u64 arg_num)
+{
+	struct __bpf_usdt_arg_spec *arg_spec;
+	struct __bpf_usdt_spec *spec;
+	int spec_id;
+
+	spec_id = __bpf_usdt_spec_id(ctx);
+	if (spec_id < 0)
+		return -ESRCH;
+
+	spec = bpf_map_lookup_elem(&__bpf_usdt_specs, &spec_id);
+	if (!spec)
+		return -ESRCH;
+
+	if (arg_num >= BPF_USDT_MAX_ARG_CNT)
+		return -ENOENT;
+	barrier_var(arg_num);
+	if (arg_num >= spec->arg_cnt)
+		return -ENOENT;
+
+	arg_spec = &spec->args[arg_num];
+
+	/* arg_spec->arg_bitshift = 64 - arg_sz * 8
+	 * so: arg_sz = (64 - arg_spec->arg_bitshift) / 8
+	 */
+	return (unsigned int)(64 - arg_spec->arg_bitshift) / 8;
+}
+
+/* Fetch USDT argument #*arg_num* (zero-indexed) and put its value into *res.
+ * Returns 0 on success; negative error, otherwise.
+ * On error *res is guaranteed to be set to zero.
+ */
+__weak __hidden
+int bpf_usdt_arg(struct pt_regs *ctx, __u64 arg_num, long *res)
+{
+	struct __bpf_usdt_spec *spec;
+	struct __bpf_usdt_arg_spec *arg_spec;
+	unsigned long val, idx;
+	int err, spec_id;
+
+	*res = 0;
+
+	spec_id = __bpf_usdt_spec_id(ctx);
+	if (spec_id < 0)
+		return -ESRCH;
+
+	spec = bpf_map_lookup_elem(&__bpf_usdt_specs, &spec_id);
+	if (!spec)
+		return -ESRCH;
+
+	if (arg_num >= BPF_USDT_MAX_ARG_CNT)
+		return -ENOENT;
+	barrier_var(arg_num);
+	if (arg_num >= spec->arg_cnt)
+		return -ENOENT;
+
+	arg_spec = &spec->args[arg_num];
+	switch (arg_spec->arg_type) {
+	case BPF_USDT_ARG_CONST:
+		/* Arg is just a constant ("-4@$-9" in USDT arg spec).
+		 * value is recorded in arg_spec->val_off directly.
+		 */
+		val = arg_spec->val_off;
+		break;
+	case BPF_USDT_ARG_REG:
+		/* Arg is in a register (e.g, "8@%rax" in USDT arg spec),
+		 * so we read the contents of that register directly from
+		 * struct pt_regs. To keep things simple user-space parts
+		 * record offsetof(struct pt_regs, <regname>) in arg_spec->reg_off.
+		 */
+		err = bpf_probe_read_kernel(&val, sizeof(val), (void *)ctx + arg_spec->reg_off);
+		if (err)
+			return err;
+		break;
+	case BPF_USDT_ARG_REG_DEREF:
+		/* Arg is in memory addressed by register, plus some offset
+		 * (e.g., "-4@-1204(%rbp)" in USDT arg spec). Register is
+		 * identified like with BPF_USDT_ARG_REG case, and the offset
+		 * is in arg_spec->val_off. We first fetch register contents
+		 * from pt_regs, then do another user-space probe read to
+		 * fetch argument value itself.
+		 */
+		err = bpf_probe_read_kernel(&val, sizeof(val), (void *)ctx + arg_spec->reg_off);
+		if (err)
+			return err;
+		err = bpf_probe_read_user(&val, sizeof(val), (void *)val + arg_spec->val_off);
+		if (err)
+			return err;
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+		val >>= arg_spec->arg_bitshift;
+#endif
+		break;
+	case BPF_USDT_ARG_SIB:
+		/* Arg is in memory addressed by SIB (Scale-Index-Base) mode
+		 * (e.g., "-1@-96(%rbp,%rax,8)" in USDT arg spec). We first
+		 * fetch the base register contents and the index register
+		 * contents from pt_regs. Then we calculate the final address
+		 * as base + (index * scale) + offset, and do a user-space
+		 * probe read to fetch the argument value.
+		 */
+		err = bpf_probe_read_kernel(&val, sizeof(val), (void *)ctx + arg_spec->reg_off);
+		if (err)
+			return err;
+		err = bpf_probe_read_kernel(&idx, sizeof(idx), (void *)ctx + arg_spec->idx_reg_off);
+		if (err)
+			return err;
+		err = bpf_probe_read_user(&val, sizeof(val), (void *)(val + (idx << arg_spec->scale_bitshift) + arg_spec->val_off));
+		if (err)
+			return err;
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+		val >>= arg_spec->arg_bitshift;
+#endif
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* cast arg from 1, 2, or 4 bytes to final 8 byte size clearing
+	 * necessary upper arg_bitshift bits, with sign extension if argument
+	 * is signed
+	 */
+	val <<= arg_spec->arg_bitshift;
+	if (arg_spec->arg_signed)
+		val = ((long)val) >> arg_spec->arg_bitshift;
+	else
+		val = val >> arg_spec->arg_bitshift;
+	*res = val;
+	return 0;
+}
+
+/* Retrieve user-specified cookie value provided during attach as
+ * bpf_usdt_opts.usdt_cookie. This serves the same purpose as BPF cookie
+ * returned by bpf_get_attach_cookie(). Libbpf's support for USDT is itself
+ * utilizing BPF cookies internally, so user can't use BPF cookie directly
+ * for USDT programs and has to use bpf_usdt_cookie() API instead.
+ */
+__weak __hidden
+long bpf_usdt_cookie(struct pt_regs *ctx)
+{
+	struct __bpf_usdt_spec *spec;
+	int spec_id;
+
+	spec_id = __bpf_usdt_spec_id(ctx);
+	if (spec_id < 0)
+		return 0;
+
+	spec = bpf_map_lookup_elem(&__bpf_usdt_specs, &spec_id);
+	if (!spec)
+		return 0;
+
+	return spec->usdt_cookie;
+}
+
+/* we rely on ___bpf_apply() and ___bpf_narg() macros already defined in bpf_tracing.h */
+#define ___bpf_usdt_args0() ctx
+#define ___bpf_usdt_args1(x) ___bpf_usdt_args0(), ({ long _x; bpf_usdt_arg(ctx, 0, &_x); _x; })
+#define ___bpf_usdt_args2(x, args...) ___bpf_usdt_args1(args), ({ long _x; bpf_usdt_arg(ctx, 1, &_x); _x; })
+#define ___bpf_usdt_args3(x, args...) ___bpf_usdt_args2(args), ({ long _x; bpf_usdt_arg(ctx, 2, &_x); _x; })
+#define ___bpf_usdt_args4(x, args...) ___bpf_usdt_args3(args), ({ long _x; bpf_usdt_arg(ctx, 3, &_x); _x; })
+#define ___bpf_usdt_args5(x, args...) ___bpf_usdt_args4(args), ({ long _x; bpf_usdt_arg(ctx, 4, &_x); _x; })
+#define ___bpf_usdt_args6(x, args...) ___bpf_usdt_args5(args), ({ long _x; bpf_usdt_arg(ctx, 5, &_x); _x; })
+#define ___bpf_usdt_args7(x, args...) ___bpf_usdt_args6(args), ({ long _x; bpf_usdt_arg(ctx, 6, &_x); _x; })
+#define ___bpf_usdt_args8(x, args...) ___bpf_usdt_args7(args), ({ long _x; bpf_usdt_arg(ctx, 7, &_x); _x; })
+#define ___bpf_usdt_args9(x, args...) ___bpf_usdt_args8(args), ({ long _x; bpf_usdt_arg(ctx, 8, &_x); _x; })
+#define ___bpf_usdt_args10(x, args...) ___bpf_usdt_args9(args), ({ long _x; bpf_usdt_arg(ctx, 9, &_x); _x; })
+#define ___bpf_usdt_args11(x, args...) ___bpf_usdt_args10(args), ({ long _x; bpf_usdt_arg(ctx, 10, &_x); _x; })
+#define ___bpf_usdt_args12(x, args...) ___bpf_usdt_args11(args), ({ long _x; bpf_usdt_arg(ctx, 11, &_x); _x; })
+#define ___bpf_usdt_args(args...) ___bpf_apply(___bpf_usdt_args, ___bpf_narg(args))(args)
+
+/*
+ * BPF_USDT serves the same purpose for USDT handlers as BPF_PROG for
+ * tp_btf/fentry/fexit BPF programs and BPF_KPROBE for kprobes.
+ * Original struct pt_regs * context is preserved as 'ctx' argument.
+ */
+#define BPF_USDT(name, args...)						    \
+name(struct pt_regs *ctx);						    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args);				    \
+typeof(name(0)) name(struct pt_regs *ctx)				    \
+{									    \
+        _Pragma("GCC diagnostic push")					    \
+        _Pragma("GCC diagnostic ignored \"-Wint-conversion\"")		    \
+        return ____##name(___bpf_usdt_args(args));			    \
+        _Pragma("GCC diagnostic pop")					    \
+}									    \
+static __always_inline typeof(name(0))					    \
+____##name(struct pt_regs *ctx, ##args)
+
+#endif /* __USDT_BPF_H__ */
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
new file mode 100644
index 000000000..2e56e3ab5
--- /dev/null
+++ b/tools/lib/bpf/usdt.c
@@ -0,0 +1,1699 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libelf.h>
+#include <gelf.h>
+#include <unistd.h>
+#include <linux/ptrace.h>
+#include <linux/kernel.h>
+
+/* s8 will be marked as poison while it's a reg of riscv */
+#if defined(__riscv)
+#define rv_s8 s8
+#endif
+
+#include "bpf.h"
+#include "libbpf.h"
+#include "libbpf_common.h"
+#include "libbpf_internal.h"
+#include "hashmap.h"
+
+/* libbpf's USDT support consists of BPF-side state/code and user-space
+ * state/code working together in concert. BPF-side parts are defined in
+ * usdt.bpf.h header library. User-space state is encapsulated by struct
+ * usdt_manager and all the supporting code centered around usdt_manager.
+ *
+ * usdt.bpf.h defines two BPF maps that usdt_manager expects: USDT spec map
+ * and IP-to-spec-ID map, which is auxiliary map necessary for kernels that
+ * don't support BPF cookie (see below). These two maps are implicitly
+ * embedded into user's end BPF object file when user's code included
+ * usdt.bpf.h. This means that libbpf doesn't do anything special to create
+ * these USDT support maps. They are created by normal libbpf logic of
+ * instantiating BPF maps when opening and loading BPF object.
+ *
+ * As such, libbpf is basically unaware of the need to do anything
+ * USDT-related until the very first call to bpf_program__attach_usdt(), which
+ * can be called by user explicitly or happen automatically during skeleton
+ * attach (or, equivalently, through generic bpf_program__attach() call). At
+ * this point, libbpf will instantiate and initialize struct usdt_manager and
+ * store it in bpf_object. USDT manager is per-BPF object construct, as each
+ * independent BPF object might or might not have USDT programs, and thus all
+ * the expected USDT-related state. There is no coordination between two
+ * bpf_object in parts of USDT attachment, they are oblivious of each other's
+ * existence and libbpf is just oblivious, dealing with bpf_object-specific
+ * USDT state.
+ *
+ * Quick crash course on USDTs.
+ *
+ * From user-space application's point of view, USDT is essentially just
+ * a slightly special function call that normally has zero overhead, unless it
+ * is being traced by some external entity (e.g, BPF-based tool). Here's how
+ * a typical application can trigger USDT probe:
+ *
+ * #include <sys/sdt.h>  // provided by systemtap-sdt-devel package
+ * // folly also provide similar functionality in folly/tracing/StaticTracepoint.h
+ *
+ * STAP_PROBE3(my_usdt_provider, my_usdt_probe_name, 123, x, &y);
+ *
+ * USDT is identified by its <provider-name>:<probe-name> pair of names. Each
+ * individual USDT has a fixed number of arguments (3 in the above example)
+ * and specifies values of each argument as if it was a function call.
+ *
+ * USDT call is actually not a function call, but is instead replaced by
+ * a single NOP instruction (thus zero overhead, effectively). But in addition
+ * to that, those USDT macros generate special SHT_NOTE ELF records in
+ * .note.stapsdt ELF section. Here's an example USDT definition as emitted by
+ * `readelf -n <binary>`:
+ *
+ *   stapsdt              0x00000089       NT_STAPSDT (SystemTap probe descriptors)
+ *   Provider: test
+ *   Name: usdt12
+ *   Location: 0x0000000000549df3, Base: 0x00000000008effa4, Semaphore: 0x0000000000a4606e
+ *   Arguments: -4@-1204(%rbp) -4@%edi -8@-1216(%rbp) -8@%r8 -4@$5 -8@%r9 8@%rdx 8@%r10 -4@$-9 -2@%cx -2@%ax -1@%sil
+ *
+ * In this case we have USDT test:usdt12 with 12 arguments.
+ *
+ * Location and base are offsets used to calculate absolute IP address of that
+ * NOP instruction that kernel can replace with an interrupt instruction to
+ * trigger instrumentation code (BPF program for all that we care about).
+ *
+ * Semaphore above is an optional feature. It records an address of a 2-byte
+ * refcount variable (normally in '.probes' ELF section) used for signaling if
+ * there is anything that is attached to USDT. This is useful for user
+ * applications if, for example, they need to prepare some arguments that are
+ * passed only to USDTs and preparation is expensive. By checking if USDT is
+ * "activated", an application can avoid paying those costs unnecessarily.
+ * Recent enough kernel has built-in support for automatically managing this
+ * refcount, which libbpf expects and relies on. If USDT is defined without
+ * associated semaphore, this value will be zero. See selftests for semaphore
+ * examples.
+ *
+ * Arguments is the most interesting part. This USDT specification string is
+ * providing information about all the USDT arguments and their locations. The
+ * part before @ sign defined byte size of the argument (1, 2, 4, or 8) and
+ * whether the argument is signed or unsigned (negative size means signed).
+ * The part after @ sign is assembly-like definition of argument location
+ * (see [0] for more details). Technically, assembler can provide some pretty
+ * advanced definitions, but libbpf is currently supporting three most common
+ * cases:
+ *   1) immediate constant, see 5th and 9th args above (-4@$5 and -4@-9);
+ *   2) register value, e.g., 8@%rdx, which means "unsigned 8-byte integer
+ *      whose value is in register %rdx";
+ *   3) memory dereference addressed by register, e.g., -4@-1204(%rbp), which
+ *      specifies signed 32-bit integer stored at offset -1204 bytes from
+ *      memory address stored in %rbp.
+ *
+ *   [0] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
+ *
+ * During attachment, libbpf parses all the relevant USDT specifications and
+ * prepares `struct usdt_spec` (USDT spec), which is then provided to BPF-side
+ * code through spec map. This allows BPF applications to quickly fetch the
+ * actual value at runtime using a simple BPF-side code.
+ *
+ * With basics out of the way, let's go over less immediately obvious aspects
+ * of supporting USDTs.
+ *
+ * First, there is no special USDT BPF program type. It is actually just
+ * a uprobe BPF program (which for kernel, at least currently, is just a kprobe
+ * program, so BPF_PROG_TYPE_KPROBE program type). With the only difference
+ * that uprobe is usually attached at the function entry, while USDT will
+ * normally be somewhere inside the function. But it should always be
+ * pointing to NOP instruction, which makes such uprobes the fastest uprobe
+ * kind.
+ *
+ * Second, it's important to realize that such STAP_PROBEn(provider, name, ...)
+ * macro invocations can end up being inlined many-many times, depending on
+ * specifics of each individual user application. So single conceptual USDT
+ * (identified by provider:name pair of identifiers) is, generally speaking,
+ * multiple uprobe locations (USDT call sites) in different places in user
+ * application. Further, again due to inlining, each USDT call site might end
+ * up having the same argument #N be located in a different place. In one call
+ * site it could be a constant, in another will end up in a register, and in
+ * yet another could be some other register or even somewhere on the stack.
+ *
+ * As such, "attaching to USDT" means (in general case) attaching the same
+ * uprobe BPF program to multiple target locations in user application, each
+ * potentially having a completely different USDT spec associated with it.
+ * To wire all this up together libbpf allocates a unique integer spec ID for
+ * each unique USDT spec. Spec IDs are allocated as sequential small integers
+ * so that they can be used as keys in array BPF map (for performance reasons).
+ * Spec ID allocation and accounting is big part of what usdt_manager is
+ * about. This state has to be maintained per-BPF object and coordinate
+ * between different USDT attachments within the same BPF object.
+ *
+ * Spec ID is the key in spec BPF map, value is the actual USDT spec layed out
+ * as struct usdt_spec. Each invocation of BPF program at runtime needs to
+ * know its associated spec ID. It gets it either through BPF cookie, which
+ * libbpf sets to spec ID during attach time, or, if kernel is too old to
+ * support BPF cookie, through IP-to-spec-ID map that libbpf maintains in such
+ * case. The latter means that some modes of operation can't be supported
+ * without BPF cookie. Such a mode is attaching to shared library "generically",
+ * without specifying target process. In such case, it's impossible to
+ * calculate absolute IP addresses for IP-to-spec-ID map, and thus such mode
+ * is not supported without BPF cookie support.
+ *
+ * Note that libbpf is using BPF cookie functionality for its own internal
+ * needs, so user itself can't rely on BPF cookie feature. To that end, libbpf
+ * provides conceptually equivalent USDT cookie support. It's still u64
+ * user-provided value that can be associated with USDT attachment. Note that
+ * this will be the same value for all USDT call sites within the same single
+ * *logical* USDT attachment. This makes sense because to user attaching to
+ * USDT is a single BPF program triggered for singular USDT probe. The fact
+ * that this is done at multiple actual locations is a mostly hidden
+ * implementation details. This USDT cookie value can be fetched with
+ * bpf_usdt_cookie(ctx) API provided by usdt.bpf.h
+ *
+ * Lastly, while single USDT can have tons of USDT call sites, it doesn't
+ * necessarily have that many different USDT specs. It very well might be
+ * that 1000 USDT call sites only need 5 different USDT specs, because all the
+ * arguments are typically contained in a small set of registers or stack
+ * locations. As such, it's wasteful to allocate as many USDT spec IDs as
+ * there are USDT call sites. So libbpf tries to be frugal and performs
+ * on-the-fly deduplication during a single USDT attachment to only allocate
+ * the minimal required amount of unique USDT specs (and thus spec IDs). This
+ * is trivially achieved by using USDT spec string (Arguments string from USDT
+ * note) as a lookup key in a hashmap. USDT spec string uniquely defines
+ * everything about how to fetch USDT arguments, so two USDT call sites
+ * sharing USDT spec string can safely share the same USDT spec and spec ID.
+ * Note, this spec string deduplication is happening only during the same USDT
+ * attachment, so each USDT spec shares the same USDT cookie value. This is
+ * not generally true for other USDT attachments within the same BPF object,
+ * as even if USDT spec string is the same, USDT cookie value can be
+ * different. It was deemed excessive to try to deduplicate across independent
+ * USDT attachments by taking into account USDT spec string *and* USDT cookie
+ * value, which would complicate spec ID accounting significantly for little
+ * gain.
+ */
+
+#define USDT_BASE_SEC ".stapsdt.base"
+#define USDT_SEMA_SEC ".probes"
+#define USDT_NOTE_SEC  ".note.stapsdt"
+#define USDT_NOTE_TYPE 3
+#define USDT_NOTE_NAME "stapsdt"
+
+/* should match exactly enum __bpf_usdt_arg_type from usdt.bpf.h */
+enum usdt_arg_type {
+	USDT_ARG_CONST,
+	USDT_ARG_REG,
+	USDT_ARG_REG_DEREF,
+	USDT_ARG_SIB,
+};
+
+/* should match exactly struct __bpf_usdt_arg_spec from usdt.bpf.h */
+struct usdt_arg_spec {
+	__u64 val_off;
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	enum usdt_arg_type arg_type: 8;
+	__u16	idx_reg_off: 12;
+	__u16	scale_bitshift: 4;
+	__u8 __reserved: 8;     /* keep reg_off offset stable */
+#else
+	__u8 __reserved: 8;     /* keep reg_off offset stable */
+	__u16	idx_reg_off: 12;
+	__u16	scale_bitshift: 4;
+	enum usdt_arg_type arg_type: 8;
+#endif
+	short reg_off;
+	bool arg_signed;
+	char arg_bitshift;
+};
+
+/* should match BPF_USDT_MAX_ARG_CNT in usdt.bpf.h */
+#define USDT_MAX_ARG_CNT 12
+
+/* should match struct __bpf_usdt_spec from usdt.bpf.h */
+struct usdt_spec {
+	struct usdt_arg_spec args[USDT_MAX_ARG_CNT];
+	__u64 usdt_cookie;
+	short arg_cnt;
+};
+
+struct usdt_note {
+	const char *provider;
+	const char *name;
+	/* USDT args specification string, e.g.:
+	 * "-4@%esi -4@-24(%rbp) -4@%ecx 2@%ax 8@%rdx"
+	 */
+	const char *args;
+	long loc_addr;
+	long base_addr;
+	long sema_addr;
+};
+
+struct usdt_target {
+	long abs_ip;
+	long rel_ip;
+	long sema_off;
+	struct usdt_spec spec;
+	const char *spec_str;
+};
+
+struct usdt_manager {
+	struct bpf_map *specs_map;
+	struct bpf_map *ip_to_spec_id_map;
+
+	int *free_spec_ids;
+	size_t free_spec_cnt;
+	size_t next_free_spec_id;
+
+	bool has_bpf_cookie;
+	bool has_sema_refcnt;
+	bool has_uprobe_multi;
+	bool has_uprobe_syscall;
+};
+
+struct usdt_manager *usdt_manager_new(struct bpf_object *obj)
+{
+	static const char *ref_ctr_sysfs_path = "/sys/bus/event_source/devices/uprobe/format/ref_ctr_offset";
+	struct usdt_manager *man;
+	struct bpf_map *specs_map, *ip_to_spec_id_map;
+
+	specs_map = bpf_object__find_map_by_name(obj, "__bpf_usdt_specs");
+	ip_to_spec_id_map = bpf_object__find_map_by_name(obj, "__bpf_usdt_ip_to_spec_id");
+	if (!specs_map || !ip_to_spec_id_map) {
+		pr_warn("usdt: failed to find USDT support BPF maps, did you forget to include bpf/usdt.bpf.h?\n");
+		return ERR_PTR(-ESRCH);
+	}
+
+	man = calloc(1, sizeof(*man));
+	if (!man)
+		return ERR_PTR(-ENOMEM);
+
+	man->specs_map = specs_map;
+	man->ip_to_spec_id_map = ip_to_spec_id_map;
+
+	/* Detect if BPF cookie is supported for kprobes.
+	 * We don't need IP-to-ID mapping if we can use BPF cookies.
+	 * Added in: 7adfc6c9b315 ("bpf: Add bpf_get_attach_cookie() BPF helper to access bpf_cookie value")
+	 */
+	man->has_bpf_cookie = kernel_supports(obj, FEAT_BPF_COOKIE);
+
+	/* Detect kernel support for automatic refcounting of USDT semaphore.
+	 * If this is not supported, USDTs with semaphores will not be supported.
+	 * Added in: a6ca88b241d5 ("trace_uprobe: support reference counter in fd-based uprobe")
+	 */
+	man->has_sema_refcnt = faccessat(AT_FDCWD, ref_ctr_sysfs_path, F_OK, AT_EACCESS) == 0;
+
+	/*
+	 * Detect kernel support for uprobe multi link to be used for attaching
+	 * usdt probes.
+	 */
+	man->has_uprobe_multi = kernel_supports(obj, FEAT_UPROBE_MULTI_LINK);
+
+	/*
+	 * Detect kernel support for uprobe() syscall, it's presence means we can
+	 * take advantage of faster nop10 uprobe handling.
+	 * Added in: 56101b69c919 ("uprobes/x86: Add uprobe syscall to speed up uprobe")
+	 */
+	man->has_uprobe_syscall = kernel_supports(obj, FEAT_UPROBE_SYSCALL);
+	return man;
+}
+
+void usdt_manager_free(struct usdt_manager *man)
+{
+	if (IS_ERR_OR_NULL(man))
+		return;
+
+	free(man->free_spec_ids);
+	free(man);
+}
+
+static int sanity_check_usdt_elf(Elf *elf, const char *path)
+{
+	GElf_Ehdr ehdr;
+	int endianness;
+
+	if (elf_kind(elf) != ELF_K_ELF) {
+		pr_warn("usdt: unrecognized ELF kind %u for '%s'\n", elf_kind(elf), path);
+		return -EBADF;
+	}
+
+	switch (gelf_getclass(elf)) {
+	case ELFCLASS64:
+		if (sizeof(void *) != 8) {
+			pr_warn("usdt: attaching to 64-bit ELF binary '%s' is not supported\n", path);
+			return -EBADF;
+		}
+		break;
+	case ELFCLASS32:
+		if (sizeof(void *) != 4) {
+			pr_warn("usdt: attaching to 32-bit ELF binary '%s' is not supported\n", path);
+			return -EBADF;
+		}
+		break;
+	default:
+		pr_warn("usdt: unsupported ELF class for '%s'\n", path);
+		return -EBADF;
+	}
+
+	if (!gelf_getehdr(elf, &ehdr))
+		return -EINVAL;
+
+	if (ehdr.e_type != ET_EXEC && ehdr.e_type != ET_DYN) {
+		pr_warn("usdt: unsupported type of ELF binary '%s' (%d), only ET_EXEC and ET_DYN are supported\n",
+			path, ehdr.e_type);
+		return -EBADF;
+	}
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	endianness = ELFDATA2LSB;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	endianness = ELFDATA2MSB;
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+	if (endianness != ehdr.e_ident[EI_DATA]) {
+		pr_warn("usdt: ELF endianness mismatch for '%s'\n", path);
+		return -EBADF;
+	}
+
+	return 0;
+}
+
+static int find_elf_sec_by_name(Elf *elf, const char *sec_name, GElf_Shdr *shdr, Elf_Scn **scn)
+{
+	Elf_Scn *sec = NULL;
+	size_t shstrndx;
+
+	if (elf_getshdrstrndx(elf, &shstrndx))
+		return -EINVAL;
+
+	/* check if ELF is corrupted and avoid calling elf_strptr if yes */
+	if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL))
+		return -EINVAL;
+
+	while ((sec = elf_nextscn(elf, sec)) != NULL) {
+		char *name;
+
+		if (!gelf_getshdr(sec, shdr))
+			return -EINVAL;
+
+		name = elf_strptr(elf, shstrndx, shdr->sh_name);
+		if (name && strcmp(sec_name, name) == 0) {
+			*scn = sec;
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+struct elf_seg {
+	long start;
+	long end;
+	long offset;
+	bool is_exec;
+};
+
+static int cmp_elf_segs(const void *_a, const void *_b)
+{
+	const struct elf_seg *a = _a;
+	const struct elf_seg *b = _b;
+
+	return a->start < b->start ? -1 : 1;
+}
+
+static int parse_elf_segs(Elf *elf, const char *path, struct elf_seg **segs, size_t *seg_cnt)
+{
+	GElf_Phdr phdr;
+	size_t n;
+	int i, err;
+	struct elf_seg *seg;
+	void *tmp;
+
+	*seg_cnt = 0;
+
+	if (elf_getphdrnum(elf, &n)) {
+		err = -errno;
+		return err;
+	}
+
+	for (i = 0; i < n; i++) {
+		if (!gelf_getphdr(elf, i, &phdr)) {
+			err = -errno;
+			return err;
+		}
+
+		pr_debug("usdt: discovered PHDR #%d in '%s': vaddr 0x%lx memsz 0x%lx offset 0x%lx type 0x%lx flags 0x%lx\n",
+			 i, path,
+			 (unsigned long)phdr.p_vaddr, (unsigned long)phdr.p_memsz, (unsigned long)phdr.p_offset,
+			 (unsigned long)phdr.p_type, (unsigned long)phdr.p_flags);
+		if (phdr.p_type != PT_LOAD)
+			continue;
+
+		tmp = libbpf_reallocarray(*segs, *seg_cnt + 1, sizeof(**segs));
+		if (!tmp)
+			return -ENOMEM;
+
+		*segs = tmp;
+		seg = *segs + *seg_cnt;
+		(*seg_cnt)++;
+
+		seg->start = phdr.p_vaddr;
+		seg->end = phdr.p_vaddr + phdr.p_memsz;
+		seg->offset = phdr.p_offset;
+		seg->is_exec = phdr.p_flags & PF_X;
+	}
+
+	if (*seg_cnt == 0) {
+		pr_warn("usdt: failed to find PT_LOAD program headers in '%s'\n", path);
+		return -ESRCH;
+	}
+
+	qsort(*segs, *seg_cnt, sizeof(**segs), cmp_elf_segs);
+	return 0;
+}
+
+static int parse_vma_segs(int pid, const char *lib_path, struct elf_seg **segs, size_t *seg_cnt)
+{
+	char path[PATH_MAX], line[4096], mode[16];
+	size_t seg_start, seg_end, seg_off;
+	struct elf_seg *seg;
+	int tmp_pid, n, i, err;
+	FILE *f;
+
+	*seg_cnt = 0;
+
+	/* Handle containerized binaries only accessible from
+	 * /proc/<pid>/root/<path>. They will be reported as just /<path> in
+	 * /proc/<pid>/maps.
+	 */
+	/* %n is not counted in sscanf() return value, so initialize it. */
+	n = 0;
+	if (sscanf(lib_path, "/proc/%d/root%n", &tmp_pid, &n) == 1 &&
+	    n > 0 && pid == tmp_pid && lib_path[n] == '/') {
+		libbpf_strlcpy(path, lib_path + n, sizeof(path));
+		goto proceed;
+	}
+
+	if (!realpath(lib_path, path)) {
+		pr_warn("usdt: failed to get absolute path of '%s' (err %s), using path as is...\n",
+			lib_path, errstr(-errno));
+		libbpf_strlcpy(path, lib_path, sizeof(path));
+	}
+
+proceed:
+	sprintf(line, "/proc/%d/maps", pid);
+	f = fopen(line, "re");
+	if (!f) {
+		err = -errno;
+		pr_warn("usdt: failed to open '%s' to get base addr of '%s': %s\n",
+			line, lib_path, errstr(err));
+		return err;
+	}
+
+	/* We need to handle lines with no path at the end:
+	 *
+	 * 7f5c6f5d1000-7f5c6f5d3000 rw-p 001c7000 08:04 21238613      /usr/lib64/libc-2.17.so
+	 * 7f5c6f5d3000-7f5c6f5d8000 rw-p 00000000 00:00 0
+	 * 7f5c6f5d8000-7f5c6f5d9000 r-xp 00000000 103:01 362990598    /data/users/andriin/linux/tools/bpf/usdt/libhello_usdt.so
+	 *
+	 * Some VMA names can be longer than the local buffer. Bound the
+	 * writes, but still consume the rest of the line.
+	 */
+	while (fscanf(f, "%zx-%zx %15s %zx %*s %*d%4095[^\n]%*[^\n]\n",
+		      &seg_start, &seg_end, mode, &seg_off, line) == 5) {
+		void *tmp;
+
+		/* to handle no path case (see above) we need to capture line
+		 * without skipping any whitespaces. So we need to strip
+		 * leading whitespaces manually here
+		 */
+		i = 0;
+		while (isblank(line[i]))
+			i++;
+		if (strcmp(line + i, path) != 0)
+			continue;
+
+		pr_debug("usdt: discovered segment for lib '%s': addrs %zx-%zx mode %s offset %zx\n",
+			 path, seg_start, seg_end, mode, seg_off);
+
+		/* ignore non-executable sections for shared libs */
+		if (mode[2] != 'x')
+			continue;
+
+		tmp = libbpf_reallocarray(*segs, *seg_cnt + 1, sizeof(**segs));
+		if (!tmp) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+
+		*segs = tmp;
+		seg = *segs + *seg_cnt;
+		*seg_cnt += 1;
+
+		seg->start = seg_start;
+		seg->end = seg_end;
+		seg->offset = seg_off;
+		seg->is_exec = true;
+	}
+
+	if (*seg_cnt == 0) {
+		pr_warn("usdt: failed to find '%s' (resolved to '%s') within PID %d memory mappings\n",
+			lib_path, path, pid);
+		err = -ESRCH;
+		goto err_out;
+	}
+
+	qsort(*segs, *seg_cnt, sizeof(**segs), cmp_elf_segs);
+	err = 0;
+err_out:
+	fclose(f);
+	return err;
+}
+
+static struct elf_seg *find_elf_seg(struct elf_seg *segs, size_t seg_cnt, long virtaddr)
+{
+	struct elf_seg *seg;
+	int i;
+
+	/* for ELF binaries (both executables and shared libraries), we are
+	 * given virtual address (absolute for executables, relative for
+	 * libraries) which should match address range of [seg_start, seg_end)
+	 */
+	for (i = 0, seg = segs; i < seg_cnt; i++, seg++) {
+		if (seg->start <= virtaddr && virtaddr < seg->end)
+			return seg;
+	}
+	return NULL;
+}
+
+static struct elf_seg *find_vma_seg(struct elf_seg *segs, size_t seg_cnt, long offset)
+{
+	struct elf_seg *seg;
+	int i;
+
+	/* for VMA segments from /proc/<pid>/maps file, provided "address" is
+	 * actually a file offset, so should be fall within logical
+	 * offset-based range of [offset_start, offset_end)
+	 */
+	for (i = 0, seg = segs; i < seg_cnt; i++, seg++) {
+		if (seg->offset <= offset && offset < seg->offset + (seg->end - seg->start))
+			return seg;
+	}
+	return NULL;
+}
+
+static int parse_usdt_note(GElf_Nhdr *nhdr, const char *data, size_t name_off,
+			   size_t desc_off, struct usdt_note *usdt_note);
+
+static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie);
+
+#if defined(__x86_64__)
+static bool has_nop_combo(int fd, long off)
+{
+	unsigned char nop_combo[11] = {
+		0x90, 0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00,
+	};
+	unsigned char buf[11];
+
+	if (pread(fd, buf, 11, off) != 11)
+		return false;
+	return memcmp(buf, nop_combo, 11) == 0;
+}
+#else
+static bool has_nop_combo(int fd, long off)
+{
+	return false;
+}
+#endif
+
+static int collect_usdt_targets(struct usdt_manager *man, struct elf_fd *elf_fd, const char *path,
+				pid_t pid, const char *usdt_provider, const char *usdt_name,
+				__u64 usdt_cookie, struct usdt_target **out_targets,
+				size_t *out_target_cnt)
+{
+	size_t off, name_off, desc_off, seg_cnt = 0, vma_seg_cnt = 0, target_cnt = 0;
+	struct elf_seg *segs = NULL, *vma_segs = NULL;
+	struct usdt_target *targets = NULL, *target;
+	Elf *elf = elf_fd->elf;
+	long base_addr = 0;
+	Elf_Scn *notes_scn, *base_scn;
+	GElf_Shdr base_shdr, notes_shdr;
+	GElf_Ehdr ehdr;
+	GElf_Nhdr nhdr;
+	Elf_Data *data;
+	int err;
+
+	*out_targets = NULL;
+	*out_target_cnt = 0;
+
+	err = find_elf_sec_by_name(elf, USDT_NOTE_SEC, &notes_shdr, &notes_scn);
+	if (err) {
+		pr_warn("usdt: no USDT notes section (%s) found in '%s'\n", USDT_NOTE_SEC, path);
+		return err;
+	}
+
+	if (notes_shdr.sh_type != SHT_NOTE || !gelf_getehdr(elf, &ehdr)) {
+		pr_warn("usdt: invalid USDT notes section (%s) in '%s'\n", USDT_NOTE_SEC, path);
+		return -EINVAL;
+	}
+
+	err = parse_elf_segs(elf, path, &segs, &seg_cnt);
+	if (err) {
+		pr_warn("usdt: failed to process ELF program segments for '%s': %s\n",
+			path, errstr(err));
+		goto err_out;
+	}
+
+	/* .stapsdt.base ELF section is optional, but is used for prelink
+	 * offset compensation (see a big comment further below)
+	 */
+	if (find_elf_sec_by_name(elf, USDT_BASE_SEC, &base_shdr, &base_scn) == 0)
+		base_addr = base_shdr.sh_addr;
+
+	data = elf_getdata(notes_scn, 0);
+	off = 0;
+	while ((off = gelf_getnote(data, off, &nhdr, &name_off, &desc_off)) > 0) {
+		long usdt_abs_ip, usdt_rel_ip, usdt_sema_off = 0;
+		struct usdt_note note;
+		struct elf_seg *seg = NULL;
+		void *tmp;
+
+		err = parse_usdt_note(&nhdr, data->d_buf, name_off, desc_off, &note);
+		if (err)
+			goto err_out;
+
+		if (strcmp(note.provider, usdt_provider) != 0 || strcmp(note.name, usdt_name) != 0)
+			continue;
+
+		/* We need to compensate "prelink effect". See [0] for details,
+		 * relevant parts quoted here:
+		 *
+		 * Each SDT probe also expands into a non-allocated ELF note. You can
+		 * find this by looking at SHT_NOTE sections and decoding the format;
+		 * see below for details. Because the note is non-allocated, it means
+		 * there is no runtime cost, and also preserved in both stripped files
+		 * and .debug files.
+		 *
+		 * However, this means that prelink won't adjust the note's contents
+		 * for address offsets. Instead, this is done via the .stapsdt.base
+		 * section. This is a special section that is added to the text. We
+		 * will only ever have one of these sections in a final link and it
+		 * will only ever be one byte long. Nothing about this section itself
+		 * matters, we just use it as a marker to detect prelink address
+		 * adjustments.
+		 *
+		 * Each probe note records the link-time address of the .stapsdt.base
+		 * section alongside the probe PC address. The decoder compares the
+		 * base address stored in the note with the .stapsdt.base section's
+		 * sh_addr. Initially these are the same, but the section header will
+		 * be adjusted by prelink. So the decoder applies the difference to
+		 * the probe PC address to get the correct prelinked PC address; the
+		 * same adjustment is applied to the semaphore address, if any.
+		 *
+		 *   [0] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
+		 */
+		usdt_abs_ip = note.loc_addr;
+		if (base_addr && note.base_addr)
+			usdt_abs_ip += base_addr - note.base_addr;
+
+		/* When attaching uprobes (which is what USDTs basically are)
+		 * kernel expects file offset to be specified, not a relative
+		 * virtual address, so we need to translate virtual address to
+		 * file offset, for both ET_EXEC and ET_DYN binaries.
+		 */
+		seg = find_elf_seg(segs, seg_cnt, usdt_abs_ip);
+		if (!seg) {
+			err = -ESRCH;
+			pr_warn("usdt: failed to find ELF program segment for '%s:%s' in '%s' at IP 0x%lx\n",
+				usdt_provider, usdt_name, path, (unsigned long)usdt_abs_ip);
+			goto err_out;
+		}
+		if (!seg->is_exec) {
+			err = -ESRCH;
+			pr_warn("usdt: matched ELF binary '%s' segment [0x%lx, 0x%lx) for '%s:%s' at IP 0x%lx is not executable\n",
+				path, (unsigned long)seg->start, (unsigned long)seg->end, usdt_provider, usdt_name,
+				(unsigned long)usdt_abs_ip);
+			goto err_out;
+		}
+		/* translate from virtual address to file offset */
+		usdt_rel_ip = usdt_abs_ip - seg->start + seg->offset;
+
+		if (ehdr.e_type == ET_DYN && !man->has_bpf_cookie) {
+			/* If we don't have BPF cookie support but need to
+			 * attach to a shared library, we'll need to know and
+			 * record absolute addresses of attach points due to
+			 * the need to lookup USDT spec by absolute IP of
+			 * triggered uprobe. Doing this resolution is only
+			 * possible when we have a specific PID of the process
+			 * that's using specified shared library. BPF cookie
+			 * removes the absolute address limitation as we don't
+			 * need to do this lookup (we just use BPF cookie as
+			 * an index of USDT spec), so for newer kernels with
+			 * BPF cookie support libbpf supports USDT attachment
+			 * to shared libraries with no PID filter.
+			 */
+			if (pid < 0) {
+				pr_warn("usdt: attaching to shared libraries without specific PID is not supported on current kernel\n");
+				err = -ENOTSUP;
+				goto err_out;
+			}
+
+			/* vma_segs are lazily initialized only if necessary */
+			if (vma_seg_cnt == 0) {
+				err = parse_vma_segs(pid, path, &vma_segs, &vma_seg_cnt);
+				if (err) {
+					pr_warn("usdt: failed to get memory segments in PID %d for shared library '%s': %s\n",
+						pid, path, errstr(err));
+					goto err_out;
+				}
+			}
+
+			seg = find_vma_seg(vma_segs, vma_seg_cnt, usdt_rel_ip);
+			if (!seg) {
+				err = -ESRCH;
+				pr_warn("usdt: failed to find shared lib memory segment for '%s:%s' in '%s' at relative IP 0x%lx\n",
+					usdt_provider, usdt_name, path, (unsigned long)usdt_rel_ip);
+				goto err_out;
+			}
+
+			usdt_abs_ip = seg->start - seg->offset + usdt_rel_ip;
+		}
+
+		pr_debug("usdt: probe for '%s:%s' in %s '%s': addr 0x%lx base 0x%lx (resolved abs_ip 0x%lx rel_ip 0x%lx) args '%s' in segment [0x%lx, 0x%lx) at offset 0x%lx\n",
+			 usdt_provider, usdt_name, ehdr.e_type == ET_EXEC ? "exec" : "lib ", path,
+			 (unsigned long)note.loc_addr, (unsigned long)note.base_addr,
+			 (unsigned long)usdt_abs_ip, (unsigned long)usdt_rel_ip, note.args,
+			 (unsigned long)(seg ? seg->start : 0), (unsigned long)(seg ? seg->end : 0),
+			 (unsigned long)(seg ? seg->offset : 0));
+
+		/* Adjust semaphore address to be a file offset */
+		if (note.sema_addr) {
+			if (!man->has_sema_refcnt) {
+				pr_warn("usdt: kernel doesn't support USDT semaphore refcounting for '%s:%s' in '%s'\n",
+					usdt_provider, usdt_name, path);
+				err = -ENOTSUP;
+				goto err_out;
+			}
+
+			seg = find_elf_seg(segs, seg_cnt, note.sema_addr);
+			if (!seg) {
+				err = -ESRCH;
+				pr_warn("usdt: failed to find ELF loadable segment with semaphore of '%s:%s' in '%s' at 0x%lx\n",
+					usdt_provider, usdt_name, path, (unsigned long)note.sema_addr);
+				goto err_out;
+			}
+			if (seg->is_exec) {
+				err = -ESRCH;
+				pr_warn("usdt: matched ELF binary '%s' segment [0x%lx, 0x%lx] for semaphore of '%s:%s' at 0x%lx is executable\n",
+					path, (unsigned long)seg->start, (unsigned long)seg->end, usdt_provider, usdt_name,
+					(unsigned long)note.sema_addr);
+				goto err_out;
+			}
+
+			usdt_sema_off = note.sema_addr - seg->start + seg->offset;
+
+			pr_debug("usdt: sema  for '%s:%s' in %s '%s': addr 0x%lx base 0x%lx (resolved 0x%lx) in segment [0x%lx, 0x%lx] at offset 0x%lx\n",
+				 usdt_provider, usdt_name, ehdr.e_type == ET_EXEC ? "exec" : "lib ",
+				 path, (unsigned long)note.sema_addr, (unsigned long)note.base_addr, (unsigned long)usdt_sema_off,
+				 (unsigned long)seg->start, (unsigned long)seg->end, (unsigned long)seg->offset);
+		}
+
+		/* Record adjusted addresses and offsets and parse USDT spec */
+		tmp = libbpf_reallocarray(targets, target_cnt + 1, sizeof(*targets));
+		if (!tmp) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+		targets = tmp;
+
+		target = &targets[target_cnt];
+		memset(target, 0, sizeof(*target));
+
+		/*
+		 * We have uprobe syscall and usdt with nop,nop10 instructions combo,
+		 * so we can place the uprobe directly on nop10 (+1) and get this probe
+		 * optimized.
+		 */
+		if (man->has_uprobe_syscall && has_nop_combo(elf_fd->fd, usdt_rel_ip)) {
+			usdt_abs_ip++;
+			usdt_rel_ip++;
+		}
+
+		target->abs_ip = usdt_abs_ip;
+		target->rel_ip = usdt_rel_ip;
+		target->sema_off = usdt_sema_off;
+
+		/* notes.args references strings from ELF itself, so they can
+		 * be referenced safely until elf_end() call
+		 */
+		target->spec_str = note.args;
+
+		err = parse_usdt_spec(&target->spec, &note, usdt_cookie);
+		if (err)
+			goto err_out;
+
+		target_cnt++;
+	}
+
+	*out_targets = targets;
+	*out_target_cnt = target_cnt;
+	err = target_cnt;
+
+err_out:
+	free(segs);
+	free(vma_segs);
+	if (err < 0)
+		free(targets);
+	return err;
+}
+
+struct bpf_link_usdt {
+	struct bpf_link link;
+
+	struct usdt_manager *usdt_man;
+
+	size_t spec_cnt;
+	int *spec_ids;
+
+	size_t uprobe_cnt;
+	struct {
+		long abs_ip;
+		struct bpf_link *link;
+	} *uprobes;
+
+	struct bpf_link *multi_link;
+};
+
+static int bpf_link_usdt_detach(struct bpf_link *link)
+{
+	struct bpf_link_usdt *usdt_link = container_of(link, struct bpf_link_usdt, link);
+	struct usdt_manager *man = usdt_link->usdt_man;
+	int i;
+
+	bpf_link__destroy(usdt_link->multi_link);
+
+	/* When having multi_link, uprobe_cnt is 0 */
+	for (i = 0; i < usdt_link->uprobe_cnt; i++) {
+		/* detach underlying uprobe link */
+		bpf_link__destroy(usdt_link->uprobes[i].link);
+		/* there is no need to update specs map because it will be
+		 * unconditionally overwritten on subsequent USDT attaches,
+		 * but if BPF cookies are not used we need to remove entry
+		 * from ip_to_spec_id map, otherwise we'll run into false
+		 * conflicting IP errors
+		 */
+		if (!man->has_bpf_cookie) {
+			/* not much we can do about errors here */
+			(void)bpf_map_delete_elem(bpf_map__fd(man->ip_to_spec_id_map),
+						  &usdt_link->uprobes[i].abs_ip);
+		}
+	}
+
+	/* try to return the list of previously used spec IDs to usdt_manager
+	 * for future reuse for subsequent USDT attaches
+	 */
+	if (!man->free_spec_ids) {
+		/* if there were no free spec IDs yet, just transfer our IDs */
+		man->free_spec_ids = usdt_link->spec_ids;
+		man->free_spec_cnt = usdt_link->spec_cnt;
+		usdt_link->spec_ids = NULL;
+	} else {
+		/* otherwise concat IDs */
+		size_t new_cnt = man->free_spec_cnt + usdt_link->spec_cnt;
+		int *new_free_ids;
+
+		new_free_ids = libbpf_reallocarray(man->free_spec_ids, new_cnt,
+						   sizeof(*new_free_ids));
+		/* If we couldn't resize free_spec_ids, we'll just leak
+		 * a bunch of free IDs; this is very unlikely to happen and if
+		 * system is so exhausted on memory, it's the least of user's
+		 * concerns, probably.
+		 * So just do our best here to return those IDs to usdt_manager.
+		 * Another edge case when we can legitimately get NULL is when
+		 * new_cnt is zero, which can happen in some edge cases, so we
+		 * need to be careful about that.
+		 */
+		if (new_free_ids || new_cnt == 0) {
+			memcpy(new_free_ids + man->free_spec_cnt, usdt_link->spec_ids,
+			       usdt_link->spec_cnt * sizeof(*usdt_link->spec_ids));
+			man->free_spec_ids = new_free_ids;
+			man->free_spec_cnt = new_cnt;
+		}
+	}
+
+	return 0;
+}
+
+static void bpf_link_usdt_dealloc(struct bpf_link *link)
+{
+	struct bpf_link_usdt *usdt_link = container_of(link, struct bpf_link_usdt, link);
+
+	free(usdt_link->spec_ids);
+	free(usdt_link->uprobes);
+	free(usdt_link);
+}
+
+static size_t specs_hash_fn(long key, void *ctx)
+{
+	return str_hash((char *)key);
+}
+
+static bool specs_equal_fn(long key1, long key2, void *ctx)
+{
+	return strcmp((char *)key1, (char *)key2) == 0;
+}
+
+static int allocate_spec_id(struct usdt_manager *man, struct hashmap *specs_hash,
+			    struct bpf_link_usdt *link, struct usdt_target *target,
+			    int *spec_id, bool *is_new)
+{
+	long tmp;
+	void *new_ids;
+	int err;
+
+	/* check if we already allocated spec ID for this spec string */
+	if (hashmap__find(specs_hash, target->spec_str, &tmp)) {
+		*spec_id = tmp;
+		*is_new = false;
+		return 0;
+	}
+
+	/* otherwise it's a new ID that needs to be set up in specs map and
+	 * returned back to usdt_manager when USDT link is detached
+	 */
+	new_ids = libbpf_reallocarray(link->spec_ids, link->spec_cnt + 1, sizeof(*link->spec_ids));
+	if (!new_ids)
+		return -ENOMEM;
+	link->spec_ids = new_ids;
+
+	/* get next free spec ID, giving preference to free list, if not empty */
+	if (man->free_spec_cnt) {
+		*spec_id = man->free_spec_ids[man->free_spec_cnt - 1];
+
+		/* cache spec ID for current spec string for future lookups */
+		err = hashmap__add(specs_hash, target->spec_str, *spec_id);
+		if (err)
+			 return err;
+
+		man->free_spec_cnt--;
+	} else {
+		/* don't allocate spec ID bigger than what fits in specs map */
+		if (man->next_free_spec_id >= bpf_map__max_entries(man->specs_map))
+			return -E2BIG;
+
+		*spec_id = man->next_free_spec_id;
+
+		/* cache spec ID for current spec string for future lookups */
+		err = hashmap__add(specs_hash, target->spec_str, *spec_id);
+		if (err)
+			 return err;
+
+		man->next_free_spec_id++;
+	}
+
+	/* remember new spec ID in the link for later return back to free list on detach */
+	link->spec_ids[link->spec_cnt] = *spec_id;
+	link->spec_cnt++;
+	*is_new = true;
+	return 0;
+}
+
+struct bpf_link *usdt_manager_attach_usdt(struct usdt_manager *man, const struct bpf_program *prog,
+					  pid_t pid, const char *path,
+					  const char *usdt_provider, const char *usdt_name,
+					  __u64 usdt_cookie)
+{
+	unsigned long *offsets = NULL, *ref_ctr_offsets = NULL;
+	int i, err, spec_map_fd, ip_map_fd;
+	LIBBPF_OPTS(bpf_uprobe_opts, opts);
+	struct hashmap *specs_hash = NULL;
+	struct bpf_link_usdt *link = NULL;
+	struct usdt_target *targets = NULL;
+	__u64 *cookies = NULL;
+	struct elf_fd elf_fd;
+	size_t target_cnt;
+
+	spec_map_fd = bpf_map__fd(man->specs_map);
+	ip_map_fd = bpf_map__fd(man->ip_to_spec_id_map);
+
+	err = elf_open(path, &elf_fd);
+	if (err)
+		return libbpf_err_ptr(err);
+
+	err = sanity_check_usdt_elf(elf_fd.elf, path);
+	if (err)
+		goto err_out;
+
+	/* normalize PID filter */
+	if (pid < 0)
+		pid = -1;
+	else if (pid == 0)
+		pid = getpid();
+
+	/* discover USDT in given binary, optionally limiting
+	 * activations to a given PID, if pid > 0
+	 */
+	err = collect_usdt_targets(man, &elf_fd, path, pid, usdt_provider, usdt_name,
+				   usdt_cookie, &targets, &target_cnt);
+	if (err <= 0) {
+		err = (err == 0) ? -ENOENT : err;
+		goto err_out;
+	}
+
+	specs_hash = hashmap__new(specs_hash_fn, specs_equal_fn, NULL);
+	if (IS_ERR(specs_hash)) {
+		err = PTR_ERR(specs_hash);
+		goto err_out;
+	}
+
+	link = calloc(1, sizeof(*link));
+	if (!link) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+
+	link->usdt_man = man;
+	link->link.detach = &bpf_link_usdt_detach;
+	link->link.dealloc = &bpf_link_usdt_dealloc;
+
+	if (man->has_uprobe_multi) {
+		offsets = calloc(target_cnt, sizeof(*offsets));
+		cookies = calloc(target_cnt, sizeof(*cookies));
+		ref_ctr_offsets = calloc(target_cnt, sizeof(*ref_ctr_offsets));
+
+		if (!offsets || !ref_ctr_offsets || !cookies) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+	} else {
+		link->uprobes = calloc(target_cnt, sizeof(*link->uprobes));
+		if (!link->uprobes) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+	}
+
+	for (i = 0; i < target_cnt; i++) {
+		struct usdt_target *target = &targets[i];
+		struct bpf_link *uprobe_link;
+		bool is_new;
+		int spec_id;
+
+		/* Spec ID can be either reused or newly allocated. If it is
+		 * newly allocated, we'll need to fill out spec map, otherwise
+		 * entire spec should be valid and can be just used by a new
+		 * uprobe. We reuse spec when USDT arg spec is identical. We
+		 * also never share specs between two different USDT
+		 * attachments ("links"), so all the reused specs already
+		 * share USDT cookie value implicitly.
+		 */
+		err = allocate_spec_id(man, specs_hash, link, target, &spec_id, &is_new);
+		if (err)
+			goto err_out;
+
+		if (is_new && bpf_map_update_elem(spec_map_fd, &spec_id, &target->spec, BPF_ANY)) {
+			err = -errno;
+			pr_warn("usdt: failed to set USDT spec #%d for '%s:%s' in '%s': %s\n",
+				spec_id, usdt_provider, usdt_name, path, errstr(err));
+			goto err_out;
+		}
+		if (!man->has_bpf_cookie &&
+		    bpf_map_update_elem(ip_map_fd, &target->abs_ip, &spec_id, BPF_NOEXIST)) {
+			err = -errno;
+			if (err == -EEXIST) {
+				pr_warn("usdt: IP collision detected for spec #%d for '%s:%s' in '%s'\n",
+				        spec_id, usdt_provider, usdt_name, path);
+			} else {
+				pr_warn("usdt: failed to map IP 0x%lx to spec #%d for '%s:%s' in '%s': %s\n",
+					(unsigned long)target->abs_ip, spec_id, usdt_provider, usdt_name,
+					path, errstr(err));
+			}
+			goto err_out;
+		}
+
+		if (man->has_uprobe_multi) {
+			offsets[i] = target->rel_ip;
+			ref_ctr_offsets[i] = target->sema_off;
+			cookies[i] = spec_id;
+		} else {
+			opts.ref_ctr_offset = target->sema_off;
+			opts.bpf_cookie = man->has_bpf_cookie ? spec_id : 0;
+			uprobe_link = bpf_program__attach_uprobe_opts(prog, pid, path,
+								      target->rel_ip, &opts);
+			err = libbpf_get_error(uprobe_link);
+			if (err) {
+				pr_warn("usdt: failed to attach uprobe #%d for '%s:%s' in '%s': %s\n",
+					i, usdt_provider, usdt_name, path, errstr(err));
+				goto err_out;
+			}
+
+			link->uprobes[i].link = uprobe_link;
+			link->uprobes[i].abs_ip = target->abs_ip;
+			link->uprobe_cnt++;
+		}
+	}
+
+	if (man->has_uprobe_multi) {
+		LIBBPF_OPTS(bpf_uprobe_multi_opts, opts_multi,
+			.ref_ctr_offsets = ref_ctr_offsets,
+			.offsets = offsets,
+			.cookies = cookies,
+			.cnt = target_cnt,
+		);
+
+		link->multi_link = bpf_program__attach_uprobe_multi(prog, pid, path,
+								    NULL, &opts_multi);
+		if (!link->multi_link) {
+			err = -errno;
+			pr_warn("usdt: failed to attach uprobe multi for '%s:%s' in '%s': %s\n",
+				usdt_provider, usdt_name, path, errstr(err));
+			goto err_out;
+		}
+
+		free(offsets);
+		free(ref_ctr_offsets);
+		free(cookies);
+	}
+
+	free(targets);
+	hashmap__free(specs_hash);
+	elf_close(&elf_fd);
+	return &link->link;
+
+err_out:
+	free(offsets);
+	free(ref_ctr_offsets);
+	free(cookies);
+
+	if (link)
+		bpf_link__destroy(&link->link);
+	free(targets);
+	hashmap__free(specs_hash);
+	elf_close(&elf_fd);
+	return libbpf_err_ptr(err);
+}
+
+/* Parse out USDT ELF note from '.note.stapsdt' section.
+ * Logic inspired by perf's code.
+ */
+static int parse_usdt_note(GElf_Nhdr *nhdr, const char *data, size_t name_off, size_t desc_off,
+			   struct usdt_note *note)
+{
+	const char *provider, *name, *args;
+	long addrs[3];
+	size_t len;
+
+	/* sanity check USDT note name and type first */
+	if (strncmp(data + name_off, USDT_NOTE_NAME, nhdr->n_namesz) != 0)
+		return -EINVAL;
+	if (nhdr->n_type != USDT_NOTE_TYPE)
+		return -EINVAL;
+
+	/* sanity check USDT note contents ("description" in ELF terminology) */
+	len = nhdr->n_descsz;
+	data = data + desc_off;
+
+	/* +3 is the very minimum required to store three empty strings */
+	if (len < sizeof(addrs) + 3)
+		return -EINVAL;
+
+	/* get location, base, and semaphore addrs */
+	memcpy(&addrs, data, sizeof(addrs));
+
+	/* parse string fields: provider, name, args */
+	provider = data + sizeof(addrs);
+
+	name = (const char *)memchr(provider, '\0', data + len - provider);
+	if (!name) /* non-zero-terminated provider */
+		return -EINVAL;
+	name++;
+	if (name >= data + len || *name == '\0') /* missing or empty name */
+		return -EINVAL;
+
+	args = memchr(name, '\0', data + len - name);
+	if (!args) /* non-zero-terminated name */
+		return -EINVAL;
+	++args;
+	if (args >= data + len) /* missing arguments spec */
+		return -EINVAL;
+
+	note->provider = provider;
+	note->name = name;
+	if (*args == '\0' || *args == ':')
+		note->args = "";
+	else
+		note->args = args;
+	note->loc_addr = addrs[0];
+	note->base_addr = addrs[1];
+	note->sema_addr = addrs[2];
+
+	return 0;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz);
+
+static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie)
+{
+	struct usdt_arg_spec *arg;
+	const char *s;
+	int arg_sz, len;
+
+	spec->usdt_cookie = usdt_cookie;
+	spec->arg_cnt = 0;
+
+	s = note->args;
+	while (s[0]) {
+		if (spec->arg_cnt >= USDT_MAX_ARG_CNT) {
+			pr_warn("usdt: too many USDT arguments (> %d) for '%s:%s' with args spec '%s'\n",
+				USDT_MAX_ARG_CNT, note->provider, note->name, note->args);
+			return -E2BIG;
+		}
+
+		arg = &spec->args[spec->arg_cnt];
+		len = parse_usdt_arg(s, spec->arg_cnt, arg, &arg_sz);
+		if (len < 0)
+			return len;
+
+		arg->arg_signed = arg_sz < 0;
+		if (arg_sz < 0)
+			arg_sz = -arg_sz;
+
+		switch (arg_sz) {
+		case 1: case 2: case 4: case 8:
+			arg->arg_bitshift = 64 - arg_sz * 8;
+			break;
+		default:
+			pr_warn("usdt: unsupported arg #%d (spec '%s') size: %d\n",
+				spec->arg_cnt, s, arg_sz);
+			return -EINVAL;
+		}
+
+		s += len;
+		spec->arg_cnt++;
+	}
+
+	return 0;
+}
+
+/* Architecture-specific logic for parsing USDT argument location specs */
+
+#if defined(__x86_64__) || defined(__i386__)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+	static struct {
+		const char *names[4];
+		size_t pt_regs_off;
+	} reg_map[] = {
+#ifdef __x86_64__
+#define reg_off(reg64, reg32) offsetof(struct pt_regs, reg64)
+#else
+#define reg_off(reg64, reg32) offsetof(struct pt_regs, reg32)
+#endif
+		{ {"rip", "eip", "", ""}, reg_off(rip, eip) },
+		{ {"rax", "eax", "ax", "al"}, reg_off(rax, eax) },
+		{ {"rbx", "ebx", "bx", "bl"}, reg_off(rbx, ebx) },
+		{ {"rcx", "ecx", "cx", "cl"}, reg_off(rcx, ecx) },
+		{ {"rdx", "edx", "dx", "dl"}, reg_off(rdx, edx) },
+		{ {"rsi", "esi", "si", "sil"}, reg_off(rsi, esi) },
+		{ {"rdi", "edi", "di", "dil"}, reg_off(rdi, edi) },
+		{ {"rbp", "ebp", "bp", "bpl"}, reg_off(rbp, ebp) },
+		{ {"rsp", "esp", "sp", "spl"}, reg_off(rsp, esp) },
+#undef reg_off
+#ifdef __x86_64__
+		{ {"r8", "r8d", "r8w", "r8b"}, offsetof(struct pt_regs, r8) },
+		{ {"r9", "r9d", "r9w", "r9b"}, offsetof(struct pt_regs, r9) },
+		{ {"r10", "r10d", "r10w", "r10b"}, offsetof(struct pt_regs, r10) },
+		{ {"r11", "r11d", "r11w", "r11b"}, offsetof(struct pt_regs, r11) },
+		{ {"r12", "r12d", "r12w", "r12b"}, offsetof(struct pt_regs, r12) },
+		{ {"r13", "r13d", "r13w", "r13b"}, offsetof(struct pt_regs, r13) },
+		{ {"r14", "r14d", "r14w", "r14b"}, offsetof(struct pt_regs, r14) },
+		{ {"r15", "r15d", "r15w", "r15b"}, offsetof(struct pt_regs, r15) },
+#endif
+	};
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(reg_map); i++) {
+		for (j = 0; j < ARRAY_SIZE(reg_map[i].names); j++) {
+			if (strcmp(reg_name, reg_map[i].names[j]) == 0)
+				return reg_map[i].pt_regs_off;
+		}
+	}
+
+	pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+	return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
+{
+	char reg_name[16] = {0}, idx_reg_name[16] = {0};
+	int len, reg_off, idx_reg_off, scale = 1;
+	long off = 0;
+
+	if (sscanf(arg_str, " %d @ %ld ( %%%15[^,] , %%%15[^,] , %d ) %n",
+		   arg_sz, &off, reg_name, idx_reg_name, &scale, &len) == 5 ||
+		sscanf(arg_str, " %d @ ( %%%15[^,] , %%%15[^,] , %d ) %n",
+		       arg_sz, reg_name, idx_reg_name, &scale, &len) == 4 ||
+		sscanf(arg_str, " %d @ %ld ( %%%15[^,] , %%%15[^)] ) %n",
+		       arg_sz, &off, reg_name, idx_reg_name, &len) == 4 ||
+		sscanf(arg_str, " %d @ ( %%%15[^,] , %%%15[^)] ) %n",
+		       arg_sz, reg_name, idx_reg_name, &len) == 3
+		) {
+		/*
+		 * Scale Index Base case:
+		 * 1@-96(%rbp,%rax,8)
+		 * 1@(%rbp,%rax,8)
+		 * 1@-96(%rbp,%rax)
+		 * 1@(%rbp,%rax)
+		 */
+		arg->arg_type = USDT_ARG_SIB;
+		arg->val_off = off;
+
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+
+		idx_reg_off = calc_pt_regs_off(idx_reg_name);
+		if (idx_reg_off < 0)
+			return idx_reg_off;
+		arg->idx_reg_off = idx_reg_off;
+
+		/* validate scale factor and set fields directly */
+		switch (scale) {
+		case 1: arg->scale_bitshift = 0; break;
+		case 2: arg->scale_bitshift = 1; break;
+		case 4: arg->scale_bitshift = 2; break;
+		case 8: arg->scale_bitshift = 3; break;
+		default:
+			pr_warn("usdt: invalid SIB scale %d, expected 1, 2, 4, 8\n", scale);
+			return -EINVAL;
+		}
+	} else if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n",
+				arg_sz, &off, reg_name, &len) == 3) {
+		/* Memory dereference case, e.g., -4@-20(%rbp) */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ ( %%%15[^)] ) %n", arg_sz, reg_name, &len) == 2) {
+		/* Memory dereference case without offset, e.g., 8@(%rsp) */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ %%%15s %n", arg_sz, reg_name, &len) == 2) {
+		/* Register read case, e.g., -4@%eax */
+		arg->arg_type = USDT_ARG_REG;
+		/* register read has no memory offset */
+		arg->val_off = 0;
+
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ $%ld %n", arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@$71 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+#elif defined(__s390x__)
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
+{
+	unsigned int reg;
+	int len;
+	long off;
+
+	if (sscanf(arg_str, " %d @ %ld ( %%r%u ) %n", arg_sz, &off, &reg, &len) == 3) {
+		/* Memory dereference case, e.g., -2@-28(%r15) */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		if (reg > 15) {
+			pr_warn("usdt: unrecognized register '%%r%u'\n", reg);
+			return -EINVAL;
+		}
+		arg->reg_off = offsetof(user_pt_regs, gprs[reg]);
+	} else if (sscanf(arg_str, " %d @ %%r%u %n", arg_sz, &reg, &len) == 2) {
+		/* Register read case, e.g., -8@%r0 */
+		arg->arg_type = USDT_ARG_REG;
+		arg->val_off = 0;
+		if (reg > 15) {
+			pr_warn("usdt: unrecognized register '%%r%u'\n", reg);
+			return -EINVAL;
+		}
+		arg->reg_off = offsetof(user_pt_regs, gprs[reg]);
+	} else if (sscanf(arg_str, " %d @ %ld %n", arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@71 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+#elif defined(__aarch64__)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+	int reg_num;
+
+	if (sscanf(reg_name, "x%d", &reg_num) == 1) {
+		if (reg_num >= 0 && reg_num < 31)
+			return offsetof(struct user_pt_regs, regs[reg_num]);
+	} else if (strcmp(reg_name, "sp") == 0) {
+		return offsetof(struct user_pt_regs, sp);
+	}
+	pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+	return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
+{
+	char reg_name[16];
+	int len, reg_off;
+	long off;
+
+	if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] , %ld ] %n", arg_sz, reg_name, &off, &len) == 3) {
+		/* Memory dereference case, e.g., -4@[sp, 96] */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", arg_sz, reg_name, &len) == 2) {
+		/* Memory dereference case, e.g., -4@[sp] */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ %ld %n", arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@5 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", arg_sz, reg_name, &len) == 2) {
+		/* Register read case, e.g., -8@x4 */
+		arg->arg_type = USDT_ARG_REG;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+#elif defined(__riscv)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+	static struct {
+		const char *name;
+		size_t pt_regs_off;
+	} reg_map[] = {
+		{ "ra", offsetof(struct user_regs_struct, ra) },
+		{ "sp", offsetof(struct user_regs_struct, sp) },
+		{ "gp", offsetof(struct user_regs_struct, gp) },
+		{ "tp", offsetof(struct user_regs_struct, tp) },
+		{ "a0", offsetof(struct user_regs_struct, a0) },
+		{ "a1", offsetof(struct user_regs_struct, a1) },
+		{ "a2", offsetof(struct user_regs_struct, a2) },
+		{ "a3", offsetof(struct user_regs_struct, a3) },
+		{ "a4", offsetof(struct user_regs_struct, a4) },
+		{ "a5", offsetof(struct user_regs_struct, a5) },
+		{ "a6", offsetof(struct user_regs_struct, a6) },
+		{ "a7", offsetof(struct user_regs_struct, a7) },
+		{ "s0", offsetof(struct user_regs_struct, s0) },
+		{ "s1", offsetof(struct user_regs_struct, s1) },
+		{ "s2", offsetof(struct user_regs_struct, s2) },
+		{ "s3", offsetof(struct user_regs_struct, s3) },
+		{ "s4", offsetof(struct user_regs_struct, s4) },
+		{ "s5", offsetof(struct user_regs_struct, s5) },
+		{ "s6", offsetof(struct user_regs_struct, s6) },
+		{ "s7", offsetof(struct user_regs_struct, s7) },
+		{ "s8", offsetof(struct user_regs_struct, rv_s8) },
+		{ "s9", offsetof(struct user_regs_struct, s9) },
+		{ "s10", offsetof(struct user_regs_struct, s10) },
+		{ "s11", offsetof(struct user_regs_struct, s11) },
+		{ "t0", offsetof(struct user_regs_struct, t0) },
+		{ "t1", offsetof(struct user_regs_struct, t1) },
+		{ "t2", offsetof(struct user_regs_struct, t2) },
+		{ "t3", offsetof(struct user_regs_struct, t3) },
+		{ "t4", offsetof(struct user_regs_struct, t4) },
+		{ "t5", offsetof(struct user_regs_struct, t5) },
+		{ "t6", offsetof(struct user_regs_struct, t6) },
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(reg_map); i++) {
+		if (strcmp(reg_name, reg_map[i].name) == 0)
+			return reg_map[i].pt_regs_off;
+	}
+
+	pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+	return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
+{
+	char reg_name[16];
+	int len, reg_off;
+	long off;
+
+	if (sscanf(arg_str, " %d @ %ld ( %15[a-z0-9] ) %n", arg_sz, &off, reg_name, &len) == 3) {
+		/* Memory dereference case, e.g., -8@-88(s0) */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ %ld %n", arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@5 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", arg_sz, reg_name, &len) == 2) {
+		/* Register read case, e.g., -8@a1 */
+		arg->arg_type = USDT_ARG_REG;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+#elif defined(__arm__)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+	static struct {
+		const char *name;
+		size_t pt_regs_off;
+	} reg_map[] = {
+		{ "r0", offsetof(struct pt_regs, uregs[0]) },
+		{ "r1", offsetof(struct pt_regs, uregs[1]) },
+		{ "r2", offsetof(struct pt_regs, uregs[2]) },
+		{ "r3", offsetof(struct pt_regs, uregs[3]) },
+		{ "r4", offsetof(struct pt_regs, uregs[4]) },
+		{ "r5", offsetof(struct pt_regs, uregs[5]) },
+		{ "r6", offsetof(struct pt_regs, uregs[6]) },
+		{ "r7", offsetof(struct pt_regs, uregs[7]) },
+		{ "r8", offsetof(struct pt_regs, uregs[8]) },
+		{ "r9", offsetof(struct pt_regs, uregs[9]) },
+		{ "r10", offsetof(struct pt_regs, uregs[10]) },
+		{ "fp", offsetof(struct pt_regs, uregs[11]) },
+		{ "ip", offsetof(struct pt_regs, uregs[12]) },
+		{ "sp", offsetof(struct pt_regs, uregs[13]) },
+		{ "lr", offsetof(struct pt_regs, uregs[14]) },
+		{ "pc", offsetof(struct pt_regs, uregs[15]) },
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(reg_map); i++) {
+		if (strcmp(reg_name, reg_map[i].name) == 0)
+			return reg_map[i].pt_regs_off;
+	}
+
+	pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+	return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
+{
+	char reg_name[16];
+	int len, reg_off;
+	long off;
+
+	if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] , #%ld ] %n",
+		   arg_sz, reg_name, &off, &len) == 3) {
+		/* Memory dereference case, e.g., -4@[fp, #96] */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", arg_sz, reg_name, &len) == 2) {
+		/* Memory dereference case, e.g., -4@[sp] */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ #%ld %n", arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@#5 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else if (sscanf(arg_str, " %d @ %15[a-z0-9] %n", arg_sz, reg_name, &len) == 2) {
+		/* Register read case, e.g., -8@r4 */
+		arg->arg_type = USDT_ARG_REG;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+#else
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
+{
+	pr_warn("usdt: libbpf doesn't support USDTs on current architecture\n");
+	return -ENOTSUP;
+}
+
+#endif
diff --git a/tools/lib/bpf/zip.c b/tools/lib/bpf/zip.c
new file mode 100644
index 000000000..88c376a83
--- /dev/null
+++ b/tools/lib/bpf/zip.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/*
+ * Routines for dealing with .zip archives.
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "libbpf_internal.h"
+#include "zip.h"
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpacked"
+#pragma GCC diagnostic ignored "-Wattributes"
+
+/* Specification of ZIP file format can be found here:
+ * https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
+ * For a high level overview of the structure of a ZIP file see
+ * sections 4.3.1 - 4.3.6.
+ *
+ * Data structures appearing in ZIP files do not contain any
+ * padding and they might be misaligned. To allow us to safely
+ * operate on pointers to such structures and their members, we
+ * declare the types as packed.
+ */
+
+#define END_OF_CD_RECORD_MAGIC 0x06054b50
+
+/* See section 4.3.16 of the spec. */
+struct end_of_cd_record {
+	/* Magic value equal to END_OF_CD_RECORD_MAGIC */
+	__u32 magic;
+
+	/* Number of the file containing this structure or 0xFFFF if ZIP64 archive.
+	 * Zip archive might span multiple files (disks).
+	 */
+	__u16 this_disk;
+
+	/* Number of the file containing the beginning of the central directory or
+	 * 0xFFFF if ZIP64 archive.
+	 */
+	__u16 cd_disk;
+
+	/* Number of central directory records on this disk or 0xFFFF if ZIP64
+	 * archive.
+	 */
+	__u16 cd_records;
+
+	/* Number of central directory records on all disks or 0xFFFF if ZIP64
+	 * archive.
+	 */
+	__u16 cd_records_total;
+
+	/* Size of the central directory record or 0xFFFFFFFF if ZIP64 archive. */
+	__u32 cd_size;
+
+	/* Offset of the central directory from the beginning of the archive or
+	 * 0xFFFFFFFF if ZIP64 archive.
+	 */
+	__u32 cd_offset;
+
+	/* Length of comment data following end of central directory record. */
+	__u16 comment_length;
+
+	/* Up to 64k of arbitrary bytes. */
+	/* uint8_t comment[comment_length] */
+} __attribute__((packed));
+
+#define CD_FILE_HEADER_MAGIC 0x02014b50
+#define FLAG_ENCRYPTED (1 << 0)
+#define FLAG_HAS_DATA_DESCRIPTOR (1 << 3)
+
+/* See section 4.3.12 of the spec. */
+struct cd_file_header {
+	/* Magic value equal to CD_FILE_HEADER_MAGIC. */
+	__u32 magic;
+	__u16 version;
+	/* Minimum zip version needed to extract the file. */
+	__u16 min_version;
+	__u16 flags;
+	__u16 compression;
+	__u16 last_modified_time;
+	__u16 last_modified_date;
+	__u32 crc;
+	__u32 compressed_size;
+	__u32 uncompressed_size;
+	__u16 file_name_length;
+	__u16 extra_field_length;
+	__u16 file_comment_length;
+	/* Number of the disk where the file starts or 0xFFFF if ZIP64 archive. */
+	__u16 disk;
+	__u16 internal_attributes;
+	__u32 external_attributes;
+	/* Offset from the start of the disk containing the local file header to the
+	 * start of the local file header.
+	 */
+	__u32 offset;
+} __attribute__((packed));
+
+#define LOCAL_FILE_HEADER_MAGIC 0x04034b50
+
+/* See section 4.3.7 of the spec. */
+struct local_file_header {
+	/* Magic value equal to LOCAL_FILE_HEADER_MAGIC. */
+	__u32 magic;
+	/* Minimum zip version needed to extract the file. */
+	__u16 min_version;
+	__u16 flags;
+	__u16 compression;
+	__u16 last_modified_time;
+	__u16 last_modified_date;
+	__u32 crc;
+	__u32 compressed_size;
+	__u32 uncompressed_size;
+	__u16 file_name_length;
+	__u16 extra_field_length;
+} __attribute__((packed));
+
+#pragma GCC diagnostic pop
+
+struct zip_archive {
+	void *data;
+	__u32 size;
+	__u32 cd_offset;
+	__u32 cd_records;
+};
+
+static void *check_access(struct zip_archive *archive, __u32 offset, __u32 size)
+{
+	if (offset + size > archive->size || offset > offset + size)
+		return NULL;
+
+	return archive->data + offset;
+}
+
+/* Returns 0 on success, -EINVAL on error and -ENOTSUP if the eocd indicates the
+ * archive uses features which are not supported.
+ */
+static int try_parse_end_of_cd(struct zip_archive *archive, __u32 offset)
+{
+	__u16 comment_length, cd_records;
+	struct end_of_cd_record *eocd;
+	__u32 cd_offset, cd_size;
+
+	eocd = check_access(archive, offset, sizeof(*eocd));
+	if (!eocd || eocd->magic != END_OF_CD_RECORD_MAGIC)
+		return -EINVAL;
+
+	comment_length = eocd->comment_length;
+	if (offset + sizeof(*eocd) + comment_length != archive->size)
+		return -EINVAL;
+
+	cd_records = eocd->cd_records;
+	if (eocd->this_disk != 0 || eocd->cd_disk != 0 || eocd->cd_records_total != cd_records)
+		/* This is a valid eocd, but we only support single-file non-ZIP64 archives. */
+		return -ENOTSUP;
+
+	cd_offset = eocd->cd_offset;
+	cd_size = eocd->cd_size;
+	if (!check_access(archive, cd_offset, cd_size))
+		return -EINVAL;
+
+	archive->cd_offset = cd_offset;
+	archive->cd_records = cd_records;
+	return 0;
+}
+
+static int find_cd(struct zip_archive *archive)
+{
+	int64_t limit, offset;
+	int rc = -EINVAL;
+
+	if (archive->size <= sizeof(struct end_of_cd_record))
+		return -EINVAL;
+
+	/* Because the end of central directory ends with a variable length array of
+	 * up to 0xFFFF bytes we can't know exactly where it starts and need to
+	 * search for it at the end of the file, scanning the (limit, offset] range.
+	 */
+	offset = archive->size - sizeof(struct end_of_cd_record);
+	limit = (int64_t)offset - (1 << 16);
+
+	for (; offset >= 0 && offset > limit && rc != 0; offset--) {
+		rc = try_parse_end_of_cd(archive, offset);
+		if (rc == -ENOTSUP)
+			break;
+	}
+	return rc;
+}
+
+struct zip_archive *zip_archive_open(const char *path)
+{
+	struct zip_archive *archive;
+	int err, fd;
+	off_t size;
+	void *data;
+
+	fd = open(path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0)
+		return ERR_PTR(-errno);
+
+	size = lseek(fd, 0, SEEK_END);
+	if (size == (off_t)-1 || size > UINT32_MAX) {
+		close(fd);
+		return ERR_PTR(-EINVAL);
+	}
+
+	data = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+	err = -errno;
+	close(fd);
+
+	if (data == MAP_FAILED)
+		return ERR_PTR(err);
+
+	archive = malloc(sizeof(*archive));
+	if (!archive) {
+		munmap(data, size);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	archive->data = data;
+	archive->size = size;
+
+	err = find_cd(archive);
+	if (err) {
+		munmap(data, size);
+		free(archive);
+		return ERR_PTR(err);
+	}
+
+	return archive;
+}
+
+void zip_archive_close(struct zip_archive *archive)
+{
+	munmap(archive->data, archive->size);
+	free(archive);
+}
+
+static struct local_file_header *local_file_header_at_offset(struct zip_archive *archive,
+							     __u32 offset)
+{
+	struct local_file_header *lfh;
+
+	lfh = check_access(archive, offset, sizeof(*lfh));
+	if (!lfh || lfh->magic != LOCAL_FILE_HEADER_MAGIC)
+		return NULL;
+
+	return lfh;
+}
+
+static int get_entry_at_offset(struct zip_archive *archive, __u32 offset, struct zip_entry *out)
+{
+	struct local_file_header *lfh;
+	__u32 compressed_size;
+	const char *name;
+	void *data;
+
+	lfh = local_file_header_at_offset(archive, offset);
+	if (!lfh)
+		return -EINVAL;
+
+	offset += sizeof(*lfh);
+	if ((lfh->flags & FLAG_ENCRYPTED) || (lfh->flags & FLAG_HAS_DATA_DESCRIPTOR))
+		return -EINVAL;
+
+	name = check_access(archive, offset, lfh->file_name_length);
+	if (!name)
+		return -EINVAL;
+
+	offset += lfh->file_name_length;
+	if (!check_access(archive, offset, lfh->extra_field_length))
+		return -EINVAL;
+
+	offset += lfh->extra_field_length;
+	compressed_size = lfh->compressed_size;
+	data = check_access(archive, offset, compressed_size);
+	if (!data)
+		return -EINVAL;
+
+	out->compression = lfh->compression;
+	out->name_length = lfh->file_name_length;
+	out->name = name;
+	out->data = data;
+	out->data_length = compressed_size;
+	out->data_offset = offset;
+
+	return 0;
+}
+
+int zip_archive_find_entry(struct zip_archive *archive, const char *file_name,
+			   struct zip_entry *out)
+{
+	size_t file_name_length = strlen(file_name);
+	__u32 i, offset = archive->cd_offset;
+
+	for (i = 0; i < archive->cd_records; ++i) {
+		__u16 cdfh_name_length, cdfh_flags;
+		struct cd_file_header *cdfh;
+		const char *cdfh_name;
+
+		cdfh = check_access(archive, offset, sizeof(*cdfh));
+		if (!cdfh || cdfh->magic != CD_FILE_HEADER_MAGIC)
+			return -EINVAL;
+
+		offset += sizeof(*cdfh);
+		cdfh_name_length = cdfh->file_name_length;
+		cdfh_name = check_access(archive, offset, cdfh_name_length);
+		if (!cdfh_name)
+			return -EINVAL;
+
+		cdfh_flags = cdfh->flags;
+		if ((cdfh_flags & FLAG_ENCRYPTED) == 0 &&
+		    (cdfh_flags & FLAG_HAS_DATA_DESCRIPTOR) == 0 &&
+		    file_name_length == cdfh_name_length &&
+		    memcmp(file_name, archive->data + offset, file_name_length) == 0) {
+			return get_entry_at_offset(archive, cdfh->offset, out);
+		}
+
+		offset += cdfh_name_length;
+		offset += cdfh->extra_field_length;
+		offset += cdfh->file_comment_length;
+	}
+
+	return -ENOENT;
+}
diff --git a/tools/lib/bpf/zip.h b/tools/lib/bpf/zip.h
new file mode 100644
index 000000000..1c1bb21fb
--- /dev/null
+++ b/tools/lib/bpf/zip.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+#ifndef __LIBBPF_ZIP_H
+#define __LIBBPF_ZIP_H
+
+#include <linux/types.h>
+
+/* Represents an open zip archive.
+ * Only basic ZIP files are supported, in particular the following are not
+ * supported:
+ * - encryption
+ * - streaming
+ * - multi-part ZIP files
+ * - ZIP64
+ */
+struct zip_archive;
+
+/* Carries information on name, compression method, and data corresponding to a
+ * file in a zip archive.
+ */
+struct zip_entry {
+	/* Compression method as defined in pkzip spec. 0 means data is uncompressed. */
+	__u16 compression;
+
+	/* Non-null terminated name of the file. */
+	const char *name;
+	/* Length of the file name. */
+	__u16 name_length;
+
+	/* Pointer to the file data. */
+	const void *data;
+	/* Length of the file data. */
+	__u32 data_length;
+	/* Offset of the file data within the archive. */
+	__u32 data_offset;
+};
+
+/* Open a zip archive. Returns NULL in case of an error. */
+struct zip_archive *zip_archive_open(const char *path);
+
+/* Close a zip archive and release resources. */
+void zip_archive_close(struct zip_archive *archive);
+
+/* Look up an entry corresponding to a file in given zip archive. */
+int zip_archive_find_entry(struct zip_archive *archive, const char *name, struct zip_entry *out);
+
+#endif
diff --git a/tools/lib/cmdline.c b/tools/lib/cmdline.c
new file mode 100644
index 000000000..c85f00f43
--- /dev/null
+++ b/tools/lib/cmdline.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * From lib/cmdline.c
+ */
+#include <stdlib.h>
+
+#if __has_attribute(__fallthrough__)
+# define fallthrough                    __attribute__((__fallthrough__))
+#else
+# define fallthrough                    do {} while (0)  /* fallthrough */
+#endif
+
+unsigned long long memparse(const char *ptr, char **retptr)
+{
+	char *endptr;	/* local pointer to end of parsed string */
+
+	unsigned long long ret = strtoll(ptr, &endptr, 0);
+
+	switch (*endptr) {
+	case 'E':
+	case 'e':
+		ret <<= 10;
+		fallthrough;
+	case 'P':
+	case 'p':
+		ret <<= 10;
+		fallthrough;
+	case 'T':
+	case 't':
+		ret <<= 10;
+		fallthrough;
+	case 'G':
+	case 'g':
+		ret <<= 10;
+		fallthrough;
+	case 'M':
+	case 'm':
+		ret <<= 10;
+		fallthrough;
+	case 'K':
+	case 'k':
+		ret <<= 10;
+		endptr++;
+		fallthrough;
+	default:
+		break;
+	}
+
+	if (retptr)
+		*retptr = endptr;
+
+	return ret;
+}
diff --git a/tools/lib/ctype.c b/tools/lib/ctype.c
new file mode 100644
index 000000000..4d2e05fd3
--- /dev/null
+++ b/tools/lib/ctype.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/lib/ctype.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/ctype.h>
+#include <linux/compiler.h>
+
+const unsigned char _ctype[] = {
+_C,_C,_C,_C,_C,_C,_C,_C,				/* 0-7 */
+_C,_C|_S,_C|_S,_C|_S,_C|_S,_C|_S,_C,_C,			/* 8-15 */
+_C,_C,_C,_C,_C,_C,_C,_C,				/* 16-23 */
+_C,_C,_C,_C,_C,_C,_C,_C,				/* 24-31 */
+_S|_SP,_P,_P,_P,_P,_P,_P,_P,				/* 32-39 */
+_P,_P,_P,_P,_P,_P,_P,_P,				/* 40-47 */
+_D,_D,_D,_D,_D,_D,_D,_D,				/* 48-55 */
+_D,_D,_P,_P,_P,_P,_P,_P,				/* 56-63 */
+_P,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U,		/* 64-71 */
+_U,_U,_U,_U,_U,_U,_U,_U,				/* 72-79 */
+_U,_U,_U,_U,_U,_U,_U,_U,				/* 80-87 */
+_U,_U,_U,_P,_P,_P,_P,_P,				/* 88-95 */
+_P,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L,		/* 96-103 */
+_L,_L,_L,_L,_L,_L,_L,_L,				/* 104-111 */
+_L,_L,_L,_L,_L,_L,_L,_L,				/* 112-119 */
+_L,_L,_L,_P,_P,_P,_P,_C,				/* 120-127 */
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,			/* 128-143 */
+0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,			/* 144-159 */
+_S|_SP,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,	/* 160-175 */
+_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,	/* 176-191 */
+_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,	/* 192-207 */
+_U,_U,_U,_U,_U,_U,_U,_P,_U,_U,_U,_U,_U,_U,_U,_L,	/* 208-223 */
+_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,	/* 224-239 */
+_L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_L,_L,_L};	/* 240-255 */
diff --git a/tools/lib/find_bit.c b/tools/lib/find_bit.c
new file mode 100644
index 000000000..6a3dc167d
--- /dev/null
+++ b/tools/lib/find_bit.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* bit search implementation
+ *
+ * Copied from lib/find_bit.c to tools/lib/find_bit.c
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * Copyright (C) 2008 IBM Corporation
+ * 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au>
+ * (Inspired by David Howell's find_next_bit implementation)
+ *
+ * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease
+ * size and improve performance, 2015.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bitmap.h>
+#include <linux/kernel.h>
+
+/*
+ * Common helper for find_bit() function family
+ * @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
+ * @MUNGE: The expression that post-processes a word containing found bit (may be empty)
+ * @size: The bitmap size in bits
+ */
+#define FIND_FIRST_BIT(FETCH, MUNGE, size)					\
+({										\
+	unsigned long idx, val, sz = (size);					\
+										\
+	for (idx = 0; idx * BITS_PER_LONG < sz; idx++) {			\
+		val = (FETCH);							\
+		if (val) {							\
+			sz = min(idx * BITS_PER_LONG + __ffs(MUNGE(val)), sz);	\
+			break;							\
+		}								\
+	}									\
+										\
+	sz;									\
+})
+
+/*
+ * Common helper for find_next_bit() function family
+ * @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
+ * @MUNGE: The expression that post-processes a word containing found bit (may be empty)
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ */
+#define FIND_NEXT_BIT(FETCH, MUNGE, size, start)				\
+({										\
+	unsigned long mask, idx, tmp, sz = (size), __start = (start);		\
+										\
+	if (unlikely(__start >= sz))						\
+		goto out;							\
+										\
+	mask = MUNGE(BITMAP_FIRST_WORD_MASK(__start));				\
+	idx = __start / BITS_PER_LONG;						\
+										\
+	for (tmp = (FETCH) & mask; !tmp; tmp = (FETCH)) {			\
+		if ((idx + 1) * BITS_PER_LONG >= sz)				\
+			goto out;						\
+		idx++;								\
+	}									\
+										\
+	sz = min(idx * BITS_PER_LONG + __ffs(MUNGE(tmp)), sz);			\
+out:										\
+	sz;									\
+})
+
+#ifndef find_first_bit
+/*
+ * Find the first set bit in a memory region.
+ */
+unsigned long _find_first_bit(const unsigned long *addr, unsigned long size)
+{
+	return FIND_FIRST_BIT(addr[idx], /* nop */, size);
+}
+#endif
+
+#ifndef find_first_and_bit
+/*
+ * Find the first set bit in two memory regions.
+ */
+unsigned long _find_first_and_bit(const unsigned long *addr1,
+				  const unsigned long *addr2,
+				  unsigned long size)
+{
+	return FIND_FIRST_BIT(addr1[idx] & addr2[idx], /* nop */, size);
+}
+#endif
+
+#ifndef find_first_zero_bit
+/*
+ * Find the first cleared bit in a memory region.
+ */
+unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size)
+{
+	return FIND_FIRST_BIT(~addr[idx], /* nop */, size);
+}
+#endif
+
+#ifndef find_next_bit
+unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, unsigned long start)
+{
+	return FIND_NEXT_BIT(addr[idx], /* nop */, nbits, start);
+}
+#endif
+
+#ifndef find_next_and_bit
+unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2,
+					unsigned long nbits, unsigned long start)
+{
+	return FIND_NEXT_BIT(addr1[idx] & addr2[idx], /* nop */, nbits, start);
+}
+#endif
+
+#ifndef find_next_zero_bit
+unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
+					 unsigned long start)
+{
+	return FIND_NEXT_BIT(~addr[idx], /* nop */, nbits, start);
+}
+#endif
diff --git a/tools/lib/hweight.c b/tools/lib/hweight.c
new file mode 100644
index 000000000..a16ebf515
--- /dev/null
+++ b/tools/lib/hweight.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bitops.h>
+#include <asm/types.h>
+
+/**
+ * hweightN - returns the hamming weight of a N-bit word
+ * @x: the word to weigh
+ *
+ * The Hamming Weight of a number is the total number of bits set in it.
+ */
+
+unsigned int __sw_hweight32(unsigned int w)
+{
+#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
+	w -= (w >> 1) & 0x55555555;
+	w =  (w & 0x33333333) + ((w >> 2) & 0x33333333);
+	w =  (w + (w >> 4)) & 0x0f0f0f0f;
+	return (w * 0x01010101) >> 24;
+#else
+	unsigned int res = w - ((w >> 1) & 0x55555555);
+	res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+	res = (res + (res >> 4)) & 0x0F0F0F0F;
+	res = res + (res >> 8);
+	return (res + (res >> 16)) & 0x000000FF;
+#endif
+}
+
+unsigned int __sw_hweight16(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x5555);
+	res = (res & 0x3333) + ((res >> 2) & 0x3333);
+	res = (res + (res >> 4)) & 0x0F0F;
+	return (res + (res >> 8)) & 0x00FF;
+}
+
+unsigned int __sw_hweight8(unsigned int w)
+{
+	unsigned int res = w - ((w >> 1) & 0x55);
+	res = (res & 0x33) + ((res >> 2) & 0x33);
+	return (res + (res >> 4)) & 0x0F;
+}
+
+unsigned long __sw_hweight64(__u64 w)
+{
+#if BITS_PER_LONG == 32
+	return __sw_hweight32((unsigned int)(w >> 32)) +
+	       __sw_hweight32((unsigned int)w);
+#elif BITS_PER_LONG == 64
+#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
+	w -= (w >> 1) & 0x5555555555555555ul;
+	w =  (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
+	w =  (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
+	return (w * 0x0101010101010101ul) >> 56;
+#else
+	__u64 res = w - ((w >> 1) & 0x5555555555555555ul);
+	res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
+	res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
+	res = res + (res >> 8);
+	res = res + (res >> 16);
+	return (res + (res >> 32)) & 0x00000000000000FFul;
+#endif
+#endif
+}
diff --git a/tools/lib/list_sort.c b/tools/lib/list_sort.c
new file mode 100644
index 000000000..bb99e493d
--- /dev/null
+++ b/tools/lib/list_sort.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/export.h>
+#include <linux/list_sort.h>
+#include <linux/list.h>
+
+/*
+ * Returns a list organized in an intermediate format suited
+ * to chaining of merge() calls: null-terminated, no reserved or
+ * sentinel head node, "prev" links not maintained.
+ */
+__attribute__((nonnull(2,3,4)))
+static struct list_head *merge(void *priv, list_cmp_func_t cmp,
+				struct list_head *a, struct list_head *b)
+{
+	struct list_head *head, **tail = &head;
+
+	for (;;) {
+		/* if equal, take 'a' -- important for sort stability */
+		if (cmp(priv, a, b) <= 0) {
+			*tail = a;
+			tail = &a->next;
+			a = a->next;
+			if (!a) {
+				*tail = b;
+				break;
+			}
+		} else {
+			*tail = b;
+			tail = &b->next;
+			b = b->next;
+			if (!b) {
+				*tail = a;
+				break;
+			}
+		}
+	}
+	return head;
+}
+
+/*
+ * Combine final list merge with restoration of standard doubly-linked
+ * list structure.  This approach duplicates code from merge(), but
+ * runs faster than the tidier alternatives of either a separate final
+ * prev-link restoration pass, or maintaining the prev links
+ * throughout.
+ */
+__attribute__((nonnull(2,3,4,5)))
+static void merge_final(void *priv, list_cmp_func_t cmp, struct list_head *head,
+			struct list_head *a, struct list_head *b)
+{
+	struct list_head *tail = head;
+
+	for (;;) {
+		/* if equal, take 'a' -- important for sort stability */
+		if (cmp(priv, a, b) <= 0) {
+			tail->next = a;
+			a->prev = tail;
+			tail = a;
+			a = a->next;
+			if (!a)
+				break;
+		} else {
+			tail->next = b;
+			b->prev = tail;
+			tail = b;
+			b = b->next;
+			if (!b) {
+				b = a;
+				break;
+			}
+		}
+	}
+
+	/* Finish linking remainder of list b on to tail */
+	tail->next = b;
+	do {
+		b->prev = tail;
+		tail = b;
+		b = b->next;
+	} while (b);
+
+	/* And the final links to make a circular doubly-linked list */
+	tail->next = head;
+	head->prev = tail;
+}
+
+/**
+ * list_sort - sort a list
+ * @priv: private data, opaque to list_sort(), passed to @cmp
+ * @head: the list to sort
+ * @cmp: the elements comparison function
+ *
+ * The comparison function @cmp must return > 0 if @a should sort after
+ * @b ("@a > @b" if you want an ascending sort), and <= 0 if @a should
+ * sort before @b *or* their original order should be preserved.  It is
+ * always called with the element that came first in the input in @a,
+ * and list_sort is a stable sort, so it is not necessary to distinguish
+ * the @a < @b and @a == @b cases.
+ *
+ * This is compatible with two styles of @cmp function:
+ * - The traditional style which returns <0 / =0 / >0, or
+ * - Returning a boolean 0/1.
+ * The latter offers a chance to save a few cycles in the comparison
+ * (which is used by e.g. plug_ctx_cmp() in block/blk-mq.c).
+ *
+ * A good way to write a multi-word comparison is::
+ *
+ *	if (a->high != b->high)
+ *		return a->high > b->high;
+ *	if (a->middle != b->middle)
+ *		return a->middle > b->middle;
+ *	return a->low > b->low;
+ *
+ *
+ * This mergesort is as eager as possible while always performing at least
+ * 2:1 balanced merges.  Given two pending sublists of size 2^k, they are
+ * merged to a size-2^(k+1) list as soon as we have 2^k following elements.
+ *
+ * Thus, it will avoid cache thrashing as long as 3*2^k elements can
+ * fit into the cache.  Not quite as good as a fully-eager bottom-up
+ * mergesort, but it does use 0.2*n fewer comparisons, so is faster in
+ * the common case that everything fits into L1.
+ *
+ *
+ * The merging is controlled by "count", the number of elements in the
+ * pending lists.  This is beautifully simple code, but rather subtle.
+ *
+ * Each time we increment "count", we set one bit (bit k) and clear
+ * bits k-1 .. 0.  Each time this happens (except the very first time
+ * for each bit, when count increments to 2^k), we merge two lists of
+ * size 2^k into one list of size 2^(k+1).
+ *
+ * This merge happens exactly when the count reaches an odd multiple of
+ * 2^k, which is when we have 2^k elements pending in smaller lists,
+ * so it's safe to merge away two lists of size 2^k.
+ *
+ * After this happens twice, we have created two lists of size 2^(k+1),
+ * which will be merged into a list of size 2^(k+2) before we create
+ * a third list of size 2^(k+1), so there are never more than two pending.
+ *
+ * The number of pending lists of size 2^k is determined by the
+ * state of bit k of "count" plus two extra pieces of information:
+ *
+ * - The state of bit k-1 (when k == 0, consider bit -1 always set), and
+ * - Whether the higher-order bits are zero or non-zero (i.e.
+ *   is count >= 2^(k+1)).
+ *
+ * There are six states we distinguish.  "x" represents some arbitrary
+ * bits, and "y" represents some arbitrary non-zero bits:
+ * 0:  00x: 0 pending of size 2^k;           x pending of sizes < 2^k
+ * 1:  01x: 0 pending of size 2^k; 2^(k-1) + x pending of sizes < 2^k
+ * 2: x10x: 0 pending of size 2^k; 2^k     + x pending of sizes < 2^k
+ * 3: x11x: 1 pending of size 2^k; 2^(k-1) + x pending of sizes < 2^k
+ * 4: y00x: 1 pending of size 2^k; 2^k     + x pending of sizes < 2^k
+ * 5: y01x: 2 pending of size 2^k; 2^(k-1) + x pending of sizes < 2^k
+ * (merge and loop back to state 2)
+ *
+ * We gain lists of size 2^k in the 2->3 and 4->5 transitions (because
+ * bit k-1 is set while the more significant bits are non-zero) and
+ * merge them away in the 5->2 transition.  Note in particular that just
+ * before the 5->2 transition, all lower-order bits are 11 (state 3),
+ * so there is one list of each smaller size.
+ *
+ * When we reach the end of the input, we merge all the pending
+ * lists, from smallest to largest.  If you work through cases 2 to
+ * 5 above, you can see that the number of elements we merge with a list
+ * of size 2^k varies from 2^(k-1) (cases 3 and 5 when x == 0) to
+ * 2^(k+1) - 1 (second merge of case 5 when x == 2^(k-1) - 1).
+ */
+__attribute__((nonnull(2,3)))
+void list_sort(void *priv, struct list_head *head, list_cmp_func_t cmp)
+{
+	struct list_head *list = head->next, *pending = NULL;
+	size_t count = 0;	/* Count of pending */
+
+	if (list == head->prev)	/* Zero or one elements */
+		return;
+
+	/* Convert to a null-terminated singly-linked list. */
+	head->prev->next = NULL;
+
+	/*
+	 * Data structure invariants:
+	 * - All lists are singly linked and null-terminated; prev
+	 *   pointers are not maintained.
+	 * - pending is a prev-linked "list of lists" of sorted
+	 *   sublists awaiting further merging.
+	 * - Each of the sorted sublists is power-of-two in size.
+	 * - Sublists are sorted by size and age, smallest & newest at front.
+	 * - There are zero to two sublists of each size.
+	 * - A pair of pending sublists are merged as soon as the number
+	 *   of following pending elements equals their size (i.e.
+	 *   each time count reaches an odd multiple of that size).
+	 *   That ensures each later final merge will be at worst 2:1.
+	 * - Each round consists of:
+	 *   - Merging the two sublists selected by the highest bit
+	 *     which flips when count is incremented, and
+	 *   - Adding an element from the input as a size-1 sublist.
+	 */
+	do {
+		size_t bits;
+		struct list_head **tail = &pending;
+
+		/* Find the least-significant clear bit in count */
+		for (bits = count; bits & 1; bits >>= 1)
+			tail = &(*tail)->prev;
+		/* Do the indicated merge */
+		if (likely(bits)) {
+			struct list_head *a = *tail, *b = a->prev;
+
+			a = merge(priv, cmp, b, a);
+			/* Install the merged result in place of the inputs */
+			a->prev = b->prev;
+			*tail = a;
+		}
+
+		/* Move one element from input list to pending */
+		list->prev = pending;
+		pending = list;
+		list = list->next;
+		pending->next = NULL;
+		count++;
+	} while (list);
+
+	/* End of input; merge together all the pending lists. */
+	list = pending;
+	pending = pending->prev;
+	for (;;) {
+		struct list_head *next = pending->prev;
+
+		if (!next)
+			break;
+		list = merge(priv, cmp, pending, list);
+		pending = next;
+	}
+	/* The final merge, rebuilding prev links */
+	merge_final(priv, cmp, head, pending, list);
+}
+EXPORT_SYMBOL(list_sort);
diff --git a/tools/lib/perf/.gitignore b/tools/lib/perf/.gitignore
new file mode 100644
index 000000000..0f5b4af63
--- /dev/null
+++ b/tools/lib/perf/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+libperf.pc
+libperf.so.*
+tests-shared
+tests-static
diff --git a/tools/lib/perf/Build b/tools/lib/perf/Build
new file mode 100644
index 000000000..e8f5b7fb9
--- /dev/null
+++ b/tools/lib/perf/Build
@@ -0,0 +1,15 @@
+libperf-y += core.o
+libperf-y += cpumap.o
+libperf-y += threadmap.o
+libperf-y += evsel.o
+libperf-y += evlist.o
+libperf-y += mmap.o
+libperf-y += zalloc.o
+libperf-y += xyarray.o
+libperf-y += lib.o
+
+$(OUTPUT)zalloc.o: ../../lib/zalloc.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
+
+tests-y += tests/
diff --git a/tools/lib/perf/Documentation/Makefile b/tools/lib/perf/Documentation/Makefile
new file mode 100644
index 000000000..573ca5b27
--- /dev/null
+++ b/tools/lib/perf/Documentation/Makefile
@@ -0,0 +1,156 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+# Most of this file is copied from tools/perf/Documentation/Makefile
+
+include ../../../scripts/Makefile.include
+include ../../../scripts/utilities.mak
+
+MAN3_TXT  = libperf.txt
+MAN7_TXT  = libperf-counting.txt libperf-sampling.txt
+MAN_EX    = examples/*.c
+
+MAN_TXT   = $(MAN3_TXT) $(MAN7_TXT)
+
+_MAN_XML  = $(patsubst %.txt,%.xml,$(MAN_TXT))
+_MAN_HTML = $(patsubst %.txt,%.html,$(MAN_TXT))
+_MAN_3    = $(patsubst %.txt,%.3,$(MAN3_TXT))
+_MAN_7    = $(patsubst %.txt,%.7,$(MAN7_TXT))
+
+MAN_XML   = $(addprefix $(OUTPUT),$(_MAN_XML))
+MAN_HTML  = $(addprefix $(OUTPUT),$(_MAN_HTML))
+MAN_3     = $(addprefix $(OUTPUT),$(_MAN_3))
+MAN_7     = $(addprefix $(OUTPUT),$(_MAN_7))
+MAN_X     = $(MAN_3) $(MAN_7)
+
+# Make the path relative to DESTDIR, not prefix
+ifndef DESTDIR
+  prefix ?=$(HOME)
+endif
+
+mandir  ?= $(prefix)/share/man
+man3dir  = $(mandir)/man3
+man7dir  = $(mandir)/man7
+
+docdir  ?= $(prefix)/share/doc/libperf
+htmldir  = $(docdir)/html
+exdir    = $(docdir)/examples
+
+ASCIIDOC        = asciidoc
+ASCIIDOC_EXTRA  = --unsafe -f asciidoc.conf
+ASCIIDOC_HTML   = xhtml11
+MANPAGE_XSL     = manpage-normal.xsl
+XMLTO_EXTRA     =
+XMLTO           =xmlto
+
+INSTALL ?= install
+RM      ?= rm -f
+
+# For asciidoc ...
+#	-7.1.2,	no extra settings are needed.
+#	8.0-,	set ASCIIDOC8.
+#
+
+# For docbook-xsl ...
+#	-1.68.1,	set ASCIIDOC_NO_ROFF? (based on changelog from 1.73.0)
+#	1.69.0,		no extra settings are needed?
+#	1.69.1-1.71.0,	set DOCBOOK_SUPPRESS_SP?
+#	1.71.1,		no extra settings are needed?
+#	1.72.0,		set DOCBOOK_XSL_172.
+#	1.73.0-,	set ASCIIDOC_NO_ROFF
+
+# If you had been using DOCBOOK_XSL_172 in an attempt to get rid
+# of 'the ".ft C" problem' in your generated manpages, and you
+# instead ended up with weird characters around callouts, try
+# using ASCIIDOC_NO_ROFF instead (it works fine with ASCIIDOC8).
+
+ifdef ASCIIDOC8
+  ASCIIDOC_EXTRA += -a asciidoc7compatible
+endif
+ifdef DOCBOOK_XSL_172
+  ASCIIDOC_EXTRA += -a libperf-asciidoc-no-roff
+  MANPAGE_XSL = manpage-1.72.xsl
+else
+  ifdef ASCIIDOC_NO_ROFF
+    # docbook-xsl after 1.72 needs the regular XSL, but will not
+    # pass-thru raw roff codes from asciidoc.conf, so turn them off.
+    ASCIIDOC_EXTRA += -a libperf-asciidoc-no-roff
+  endif
+endif
+ifdef MAN_BOLD_LITERAL
+  XMLTO_EXTRA += -m manpage-bold-literal.xsl
+endif
+ifdef DOCBOOK_SUPPRESS_SP
+  XMLTO_EXTRA += -m manpage-suppress-sp.xsl
+endif
+
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+export DESTDIR DESTDIR_SQ
+
+# Please note that there is a minor bug in asciidoc.
+# The version after 6.0.3 _will_ include the patch found here:
+#   http://marc.theaimsgroup.com/?l=libtraceevent&m=111558757202243&w=2
+#
+# Until that version is released you may have to apply the patch
+# yourself - yes, all 6 characters of it!
+
+QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
+QUIET_SUBDIR1  =
+
+ifneq ($(findstring $(MAKEFLAGS),w),w)
+  PRINT_DIR = --no-print-directory
+else # "make -w"
+  NO_SUBDIR = :
+endif
+
+ifneq ($(findstring $(MAKEFLAGS),s),s)
+  ifneq ($(V),1)
+    QUIET_ASCIIDOC = @echo '  ASCIIDOC '$@;
+    QUIET_XMLTO    = @echo '  XMLTO    '$@;
+  endif
+endif
+
+all: $(MAN_X) $(MAN_HTML)
+
+$(MAN_HTML) $(MAN_X): asciidoc.conf
+
+install-man: all
+	$(call QUIET_INSTALL, man) \
+		$(INSTALL) -d -m 755 $(DESTDIR)$(man3dir); \
+		$(INSTALL) -m 644 $(MAN_3) $(DESTDIR)$(man3dir); \
+		$(INSTALL) -d -m 755 $(DESTDIR)$(man7dir); \
+		$(INSTALL) -m 644 $(MAN_7) $(DESTDIR)$(man7dir);
+
+install-html: $(MAN_HTML)
+	$(call QUIET_INSTALL, html) \
+		$(INSTALL) -d -m 755 $(DESTDIR)$(htmldir); \
+		$(INSTALL) -m 644 $(MAN_HTML) $(DESTDIR)$(htmldir); \
+
+install-examples:
+	$(call QUIET_INSTALL, examples) \
+		$(INSTALL) -d -m 755 $(DESTDIR)$(exdir); \
+		$(INSTALL) -m 644 $(MAN_EX) $(DESTDIR)$(exdir); \
+
+CLEAN_FILES =					\
+	$(MAN_XML) $(addsuffix +,$(MAN_XML))	\
+	$(MAN_HTML) $(addsuffix +,$(MAN_HTML))	\
+	$(MAN_X)
+
+clean:
+	$(call QUIET_CLEAN, Documentation) $(RM) $(CLEAN_FILES)
+
+$(MAN_3): $(OUTPUT)%.3: %.xml
+	$(QUIET_XMLTO)$(XMLTO) -o $(OUTPUT). -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
+
+$(MAN_7): $(OUTPUT)%.7: %.xml
+	$(QUIET_XMLTO)$(XMLTO) -o $(OUTPUT). -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
+
+$(MAN_XML): $(OUTPUT)%.xml: %.txt
+	$(QUIET_ASCIIDOC)$(ASCIIDOC) -b docbook -d manpage \
+		$(ASCIIDOC_EXTRA) -alibperf_version=$(EVENT_PARSE_VERSION) -o $@+ $< && \
+	mv $@+ $@
+
+$(MAN_HTML): $(OUTPUT)%.html: %.txt
+	$(QUIET_ASCIIDOC)$(ASCIIDOC) -b $(ASCIIDOC_HTML) -d manpage \
+	$(ASCIIDOC_EXTRA) -aperf_version=$(EVENT_PARSE_VERSION) -o $@+ $< && \
+	mv $@+ $@
diff --git a/tools/lib/perf/Documentation/asciidoc.conf b/tools/lib/perf/Documentation/asciidoc.conf
new file mode 100644
index 000000000..9d5a5a5ee
--- /dev/null
+++ b/tools/lib/perf/Documentation/asciidoc.conf
@@ -0,0 +1,120 @@
+## linktep: macro
+#
+# Usage: linktep:command[manpage-section]
+#
+# Note, {0} is the manpage section, while {target} is the command.
+#
+# Show TEP link as: <command>(<section>); if section is defined, else just show
+# the command.
+
+[macros]
+(?su)[\\]?(?P<name>linktep):(?P<target>\S*?)\[(?P<attrlist>.*?)\]=
+
+[attributes]
+asterisk=&#42;
+plus=&#43;
+caret=&#94;
+startsb=&#91;
+endsb=&#93;
+tilde=&#126;
+
+ifdef::backend-docbook[]
+[linktep-inlinemacro]
+{0%{target}}
+{0#<citerefentry>}
+{0#<refentrytitle>{target}</refentrytitle><manvolnum>{0}</manvolnum>}
+{0#</citerefentry>}
+endif::backend-docbook[]
+
+ifdef::backend-docbook[]
+ifndef::tep-asciidoc-no-roff[]
+# "unbreak" docbook-xsl v1.68 for manpages. v1.69 works with or without this.
+# v1.72 breaks with this because it replaces dots not in roff requests.
+[listingblock]
+<example><title>{title}</title>
+<literallayout>
+ifdef::doctype-manpage[]
+&#10;.ft C&#10;
+endif::doctype-manpage[]
+|
+ifdef::doctype-manpage[]
+&#10;.ft&#10;
+endif::doctype-manpage[]
+</literallayout>
+{title#}</example>
+endif::tep-asciidoc-no-roff[]
+
+ifdef::tep-asciidoc-no-roff[]
+ifdef::doctype-manpage[]
+# The following two small workarounds insert a simple paragraph after screen
+[listingblock]
+<example><title>{title}</title>
+<literallayout>
+|
+</literallayout><simpara></simpara>
+{title#}</example>
+
+[verseblock]
+<formalpara{id? id="{id}"}><title>{title}</title><para>
+{title%}<literallayout{id? id="{id}"}>
+{title#}<literallayout>
+|
+</literallayout>
+{title#}</para></formalpara>
+{title%}<simpara></simpara>
+endif::doctype-manpage[]
+endif::tep-asciidoc-no-roff[]
+endif::backend-docbook[]
+
+ifdef::doctype-manpage[]
+ifdef::backend-docbook[]
+[header]
+template::[header-declarations]
+<refentry>
+<refmeta>
+<refentrytitle>{mantitle}</refentrytitle>
+<manvolnum>{manvolnum}</manvolnum>
+<refmiscinfo class="source">libperf</refmiscinfo>
+<refmiscinfo class="version">{libperf_version}</refmiscinfo>
+<refmiscinfo class="manual">libperf Manual</refmiscinfo>
+</refmeta>
+<refnamediv>
+  <refname>{manname1}</refname>
+  <refname>{manname2}</refname>
+  <refname>{manname3}</refname>
+  <refname>{manname4}</refname>
+  <refname>{manname5}</refname>
+  <refname>{manname6}</refname>
+  <refname>{manname7}</refname>
+  <refname>{manname8}</refname>
+  <refname>{manname9}</refname>
+  <refname>{manname10}</refname>
+  <refname>{manname11}</refname>
+  <refname>{manname12}</refname>
+  <refname>{manname13}</refname>
+  <refname>{manname14}</refname>
+  <refname>{manname15}</refname>
+  <refname>{manname16}</refname>
+  <refname>{manname17}</refname>
+  <refname>{manname18}</refname>
+  <refname>{manname19}</refname>
+  <refname>{manname20}</refname>
+  <refname>{manname21}</refname>
+  <refname>{manname22}</refname>
+  <refname>{manname23}</refname>
+  <refname>{manname24}</refname>
+  <refname>{manname25}</refname>
+  <refname>{manname26}</refname>
+  <refname>{manname27}</refname>
+  <refname>{manname28}</refname>
+  <refname>{manname29}</refname>
+  <refname>{manname30}</refname>
+  <refpurpose>{manpurpose}</refpurpose>
+</refnamediv>
+endif::backend-docbook[]
+endif::doctype-manpage[]
+
+ifdef::backend-xhtml11[]
+[linktep-inlinemacro]
+<a href="{target}.html">{target}{0?({0})}</a>
+endif::backend-xhtml11[]
diff --git a/tools/lib/perf/Documentation/examples/counting.c b/tools/lib/perf/Documentation/examples/counting.c
new file mode 100644
index 000000000..608569357
--- /dev/null
+++ b/tools/lib/perf/Documentation/examples/counting.c
@@ -0,0 +1,83 @@
+#include <linux/perf_event.h>
+#include <perf/evlist.h>
+#include <perf/evsel.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <perf/mmap.h>
+#include <perf/core.h>
+#include <perf/event.h>
+#include <stdio.h>
+#include <unistd.h>
+
+static int libperf_print(enum libperf_print_level level,
+                         const char *fmt, va_list ap)
+{
+	return vfprintf(stderr, fmt, ap);
+}
+
+int main(int argc, char **argv)
+{
+	int count = 100000, err = 0;
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	struct perf_thread_map *threads;
+	struct perf_counts_values counts;
+
+	struct perf_event_attr attr1 = {
+		.type        = PERF_TYPE_SOFTWARE,
+		.config      = PERF_COUNT_SW_CPU_CLOCK,
+		.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,
+		.disabled    = 1,
+	};
+	struct perf_event_attr attr2 = {
+		.type        = PERF_TYPE_SOFTWARE,
+		.config      = PERF_COUNT_SW_TASK_CLOCK,
+		.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,
+		.disabled    = 1,
+	};
+
+	libperf_init(libperf_print);
+	threads = perf_thread_map__new_dummy();
+	if (!threads) {
+		fprintf(stderr, "failed to create threads\n");
+		return -1;
+	}
+	perf_thread_map__set_pid(threads, 0, 0);
+	evlist = perf_evlist__new();
+	if (!evlist) {
+		fprintf(stderr, "failed to create evlist\n");
+		goto out_threads;
+	}
+	evsel = perf_evsel__new(&attr1);
+	if (!evsel) {
+		fprintf(stderr, "failed to create evsel1\n");
+		goto out_evlist;
+	}
+	perf_evlist__add(evlist, evsel);
+	evsel = perf_evsel__new(&attr2);
+	if (!evsel) {
+		fprintf(stderr, "failed to create evsel2\n");
+		goto out_evlist;
+	}
+	perf_evlist__add(evlist, evsel);
+	perf_evlist__set_maps(evlist, NULL, threads);
+	err = perf_evlist__open(evlist);
+	if (err) {
+		fprintf(stderr, "failed to open evsel\n");
+		goto out_evlist;
+	}
+	perf_evlist__enable(evlist);
+	while (count--);
+	perf_evlist__disable(evlist);
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		perf_evsel__read(evsel, 0, 0, &counts);
+		fprintf(stdout, "count %llu, enabled %llu, run %llu\n",
+				counts.val, counts.ena, counts.run);
+	}
+	perf_evlist__close(evlist);
+out_evlist:
+	perf_evlist__delete(evlist);
+out_threads:
+	perf_thread_map__put(threads);
+	return err;
+}
diff --git a/tools/lib/perf/Documentation/examples/sampling.c b/tools/lib/perf/Documentation/examples/sampling.c
new file mode 100644
index 000000000..bc142f066
--- /dev/null
+++ b/tools/lib/perf/Documentation/examples/sampling.c
@@ -0,0 +1,119 @@
+#include <linux/perf_event.h>
+#include <perf/evlist.h>
+#include <perf/evsel.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <perf/mmap.h>
+#include <perf/core.h>
+#include <perf/event.h>
+#include <stdio.h>
+#include <unistd.h>
+
+static int libperf_print(enum libperf_print_level level,
+                         const char *fmt, va_list ap)
+{
+	return vfprintf(stderr, fmt, ap);
+}
+
+union u64_swap {
+	__u64 val64;
+	__u32 val32[2];
+};
+
+int main(int argc, char **argv)
+{
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	struct perf_mmap *map;
+	struct perf_cpu_map *cpus;
+	struct perf_event_attr attr = {
+		.type        = PERF_TYPE_HARDWARE,
+		.config      = PERF_COUNT_HW_CPU_CYCLES,
+		.disabled    = 1,
+		.freq        = 1,
+		.sample_freq = 10,
+		.sample_type = PERF_SAMPLE_IP|PERF_SAMPLE_TID|PERF_SAMPLE_CPU|PERF_SAMPLE_PERIOD,
+	};
+	int err = -1;
+	union perf_event *event;
+
+	libperf_init(libperf_print);
+
+	cpus = perf_cpu_map__new_online_cpus();
+	if (!cpus) {
+		fprintf(stderr, "failed to create cpus\n");
+		return -1;
+	}
+
+	evlist = perf_evlist__new();
+	if (!evlist) {
+		fprintf(stderr, "failed to create evlist\n");
+		goto out_cpus;
+	}
+
+	evsel = perf_evsel__new(&attr);
+	if (!evsel) {
+		fprintf(stderr, "failed to create cycles\n");
+		goto out_cpus;
+	}
+
+	perf_evlist__add(evlist, evsel);
+
+	perf_evlist__set_maps(evlist, cpus, NULL);
+
+	err = perf_evlist__open(evlist);
+	if (err) {
+		fprintf(stderr, "failed to open evlist\n");
+		goto out_evlist;
+	}
+
+	err = perf_evlist__mmap(evlist, 4);
+	if (err) {
+		fprintf(stderr, "failed to mmap evlist\n");
+		goto out_evlist;
+	}
+
+	perf_evlist__enable(evlist);
+	sleep(3);
+	perf_evlist__disable(evlist);
+
+	perf_evlist__for_each_mmap(evlist, map, false) {
+		if (perf_mmap__read_init(map) < 0)
+			continue;
+
+		while ((event = perf_mmap__read_event(map)) != NULL) {
+			int cpu, pid, tid;
+			__u64 ip, period, *array;
+			union u64_swap u;
+
+			array = event->sample.array;
+
+			ip = *array;
+			array++;
+
+			u.val64 = *array;
+			pid = u.val32[0];
+			tid = u.val32[1];
+			array++;
+
+			u.val64 = *array;
+			cpu = u.val32[0];
+			array++;
+
+			period = *array;
+
+			fprintf(stdout, "cpu %3d, pid %6d, tid %6d, ip %20llx, period %20llu\n",
+				cpu, pid, tid, ip, period);
+
+			perf_mmap__consume(map);
+		}
+
+		perf_mmap__read_done(map);
+	}
+
+out_evlist:
+	perf_evlist__delete(evlist);
+out_cpus:
+	perf_cpu_map__put(cpus);
+	return err;
+}
diff --git a/tools/lib/perf/Documentation/libperf-counting.txt b/tools/lib/perf/Documentation/libperf-counting.txt
new file mode 100644
index 000000000..8b75efcd6
--- /dev/null
+++ b/tools/lib/perf/Documentation/libperf-counting.txt
@@ -0,0 +1,213 @@
+libperf-counting(7)
+===================
+
+NAME
+----
+libperf-counting - counting interface
+
+DESCRIPTION
+-----------
+The counting interface provides API to measure and get count for specific perf events.
+
+The following test tries to explain count on `counting.c` example.
+
+It is by no means complete guide to counting, but shows libperf basic API for counting.
+
+The `counting.c` comes with libperf package and can be compiled and run like:
+
+[source,bash]
+--
+$ gcc -o counting counting.c -lperf
+$ sudo ./counting
+count 176792, enabled 176944, run 176944
+count 176242, enabled 176242, run 176242
+--
+
+It requires root access, because of the `PERF_COUNT_SW_CPU_CLOCK` event,
+which is available only for root.
+
+The `counting.c` example monitors two events on the current process and displays
+their count, in a nutshell it:
+
+* creates events
+* adds them to the event list
+* opens and enables events through the event list
+* does some workload
+* disables events
+* reads and displays event counts
+* destroys the event list
+
+The first thing you need to do before using libperf is to call init function:
+
+[source,c]
+--
+  8 static int libperf_print(enum libperf_print_level level,
+  9                          const char *fmt, va_list ap)
+ 10 {
+ 11         return vfprintf(stderr, fmt, ap);
+ 12 }
+
+ 14 int main(int argc, char **argv)
+ 15 {
+ ...
+ 35         libperf_init(libperf_print);
+--
+
+It will setup the library and sets function for debug output from library.
+
+The `libperf_print` callback will receive any message with its debug level,
+defined as:
+
+[source,c]
+--
+enum libperf_print_level {
+        LIBPERF_ERR,
+        LIBPERF_WARN,
+        LIBPERF_INFO,
+        LIBPERF_DEBUG,
+        LIBPERF_DEBUG2,
+        LIBPERF_DEBUG3,
+};
+--
+
+Once the setup is complete we start by defining specific events using the `struct perf_event_attr`.
+
+We create software events for cpu and task:
+
+[source,c]
+--
+ 20         struct perf_event_attr attr1 = {
+ 21                 .type        = PERF_TYPE_SOFTWARE,
+ 22                 .config      = PERF_COUNT_SW_CPU_CLOCK,
+ 23                 .read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,
+ 24                 .disabled    = 1,
+ 25         };
+ 26         struct perf_event_attr attr2 = {
+ 27                 .type        = PERF_TYPE_SOFTWARE,
+ 28                 .config      = PERF_COUNT_SW_TASK_CLOCK,
+ 29                 .read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,
+ 30                 .disabled    = 1,
+ 31         };
+--
+
+The `read_format` setup tells perf to include timing details together with each count.
+
+Next step is to prepare threads map.
+
+In this case we will monitor current process, so we create threads map with single pid (0):
+
+[source,c]
+--
+ 37         threads = perf_thread_map__new_dummy();
+ 38         if (!threads) {
+ 39                 fprintf(stderr, "failed to create threads\n");
+ 40                 return -1;
+ 41         }
+ 42
+ 43         perf_thread_map__set_pid(threads, 0, 0);
+--
+
+Now we create libperf's event list, which will serve as holder for the events we want:
+
+[source,c]
+--
+ 45         evlist = perf_evlist__new();
+ 46         if (!evlist) {
+ 47                 fprintf(stderr, "failed to create evlist\n");
+ 48                 goto out_threads;
+ 49         }
+--
+
+We create libperf's events for the attributes we defined earlier and add them to the list:
+
+[source,c]
+--
+ 51         evsel = perf_evsel__new(&attr1);
+ 52         if (!evsel) {
+ 53                 fprintf(stderr, "failed to create evsel1\n");
+ 54                 goto out_evlist;
+ 55         }
+ 56
+ 57         perf_evlist__add(evlist, evsel);
+ 58
+ 59         evsel = perf_evsel__new(&attr2);
+ 60         if (!evsel) {
+ 61                 fprintf(stderr, "failed to create evsel2\n");
+ 62                 goto out_evlist;
+ 63         }
+ 64
+ 65         perf_evlist__add(evlist, evsel);
+--
+
+Configure event list with the thread map and open events:
+
+[source,c]
+--
+ 67         perf_evlist__set_maps(evlist, NULL, threads);
+ 68
+ 69         err = perf_evlist__open(evlist);
+ 70         if (err) {
+ 71                 fprintf(stderr, "failed to open evsel\n");
+ 72                 goto out_evlist;
+ 73         }
+--
+
+Both events are created as disabled (note the `disabled = 1` assignment above),
+so we need to enable the whole list explicitly (both events).
+
+From this moment events are counting and we can do our workload.
+
+When we are done we disable the events list.
+
+[source,c]
+--
+ 75         perf_evlist__enable(evlist);
+ 76
+ 77         while (count--);
+ 78
+ 79         perf_evlist__disable(evlist);
+--
+
+Now we need to get the counts from events, following code iterates through the
+events list and read counts:
+
+[source,c]
+--
+ 81         perf_evlist__for_each_evsel(evlist, evsel) {
+ 82                 perf_evsel__read(evsel, 0, 0, &counts);
+ 83                 fprintf(stdout, "count %llu, enabled %llu, run %llu\n",
+ 84                         counts.val, counts.ena, counts.run);
+ 85         }
+--
+
+And finally cleanup.
+
+We close the whole events list (both events) and remove it together with the threads map:
+
+[source,c]
+--
+ 87         perf_evlist__close(evlist);
+ 88
+ 89 out_evlist:
+ 90         perf_evlist__delete(evlist);
+ 91 out_threads:
+ 92         perf_thread_map__put(threads);
+ 93         return err;
+ 94 }
+--
+
+REPORTING BUGS
+--------------
+Report bugs to <linux-perf-users@vger.kernel.org>.
+
+LICENSE
+-------
+libperf is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+
+SEE ALSO
+--------
+libperf(3), libperf-sampling(7)
diff --git a/tools/lib/perf/Documentation/libperf-sampling.txt b/tools/lib/perf/Documentation/libperf-sampling.txt
new file mode 100644
index 000000000..2378980fa
--- /dev/null
+++ b/tools/lib/perf/Documentation/libperf-sampling.txt
@@ -0,0 +1,244 @@
+libperf-sampling(7)
+===================
+
+NAME
+----
+libperf-sampling - sampling interface
+
+
+DESCRIPTION
+-----------
+The sampling interface provides API to measure and get count for specific perf events.
+
+The following test tries to explain count on `sampling.c` example.
+
+It is by no means complete guide to sampling, but shows libperf basic API for sampling.
+
+The `sampling.c` comes with libperf package and can be compiled and run like:
+
+[source,bash]
+--
+$ gcc -o sampling sampling.c -lperf
+$ sudo ./sampling
+cpu   0, pid      0, tid      0, ip     ffffffffad06c4e6, period                    1
+cpu   0, pid   4465, tid   4469, ip     ffffffffad118748, period             18322959
+cpu   0, pid      0, tid      0, ip     ffffffffad115722, period             33544846
+cpu   0, pid   4465, tid   4470, ip         7f84fe0cdad6, period             23687474
+cpu   0, pid      0, tid      0, ip     ffffffffad9e0349, period             34255790
+cpu   0, pid   4465, tid   4469, ip     ffffffffad136581, period             38664069
+cpu   0, pid      0, tid      0, ip     ffffffffad9e55e2, period             21922384
+cpu   0, pid   4465, tid   4470, ip         7f84fe0ebebf, period             17655175
+...
+--
+
+It requires root access, because it uses hardware cycles event.
+
+The `sampling.c` example profiles/samples all CPUs with hardware cycles, in a
+nutshell it:
+
+- creates events
+- adds them to the event list
+- opens and enables events through the event list
+- sleeps for 3 seconds
+- disables events
+- reads and displays recorded samples
+- destroys the event list
+
+The first thing you need to do before using libperf is to call init function:
+
+[source,c]
+--
+ 12 static int libperf_print(enum libperf_print_level level,
+ 13                          const char *fmt, va_list ap)
+ 14 {
+ 15         return vfprintf(stderr, fmt, ap);
+ 16 }
+
+ 23 int main(int argc, char **argv)
+ 24 {
+ ...
+ 40         libperf_init(libperf_print);
+--
+
+It will setup the library and sets function for debug output from library.
+
+The `libperf_print` callback will receive any message with its debug level,
+defined as:
+
+[source,c]
+--
+enum libperf_print_level {
+        LIBPERF_ERR,
+        LIBPERF_WARN,
+        LIBPERF_INFO,
+        LIBPERF_DEBUG,
+        LIBPERF_DEBUG2,
+        LIBPERF_DEBUG3,
+};
+--
+
+Once the setup is complete we start by defining cycles event using the `struct perf_event_attr`:
+
+[source,c]
+--
+ 29         struct perf_event_attr attr = {
+ 30                 .type        = PERF_TYPE_HARDWARE,
+ 31                 .config      = PERF_COUNT_HW_CPU_CYCLES,
+ 32                 .disabled    = 1,
+ 33                 .freq        = 1,
+ 34                 .sample_freq = 10,
+ 35                 .sample_type = PERF_SAMPLE_IP|PERF_SAMPLE_TID|PERF_SAMPLE_CPU|PERF_SAMPLE_PERIOD,
+ 36         };
+--
+
+Next step is to prepare CPUs map.
+
+In this case we will monitor all the available CPUs:
+
+[source,c]
+--
+ 42         cpus = perf_cpu_map__new_online_cpus();
+ 43         if (!cpus) {
+ 44                 fprintf(stderr, "failed to create cpus\n");
+ 45                 return -1;
+ 46         }
+--
+
+Now we create libperf's event list, which will serve as holder for the cycles event:
+
+[source,c]
+--
+ 48         evlist = perf_evlist__new();
+ 49         if (!evlist) {
+ 50                 fprintf(stderr, "failed to create evlist\n");
+ 51                 goto out_cpus;
+ 52         }
+--
+
+We create libperf's event for the cycles attribute we defined earlier and add it to the list:
+
+[source,c]
+--
+ 54         evsel = perf_evsel__new(&attr);
+ 55         if (!evsel) {
+ 56                 fprintf(stderr, "failed to create cycles\n");
+ 57                 goto out_cpus;
+ 58         }
+ 59
+ 60         perf_evlist__add(evlist, evsel);
+--
+
+Configure event list with the cpus map and open event:
+
+[source,c]
+--
+ 62         perf_evlist__set_maps(evlist, cpus, NULL);
+ 63
+ 64         err = perf_evlist__open(evlist);
+ 65         if (err) {
+ 66                 fprintf(stderr, "failed to open evlist\n");
+ 67                 goto out_evlist;
+ 68         }
+--
+
+Once the events list is open, we can create memory maps AKA perf ring buffers:
+
+[source,c]
+--
+ 70         err = perf_evlist__mmap(evlist, 4);
+ 71         if (err) {
+ 72                 fprintf(stderr, "failed to mmap evlist\n");
+ 73                 goto out_evlist;
+ 74         }
+--
+
+The event is created as disabled (note the `disabled = 1` assignment above),
+so we need to enable the events list explicitly.
+
+From this moment the cycles event is sampling.
+
+We will sleep for 3 seconds while the ring buffers get data from all CPUs, then we disable the events list.
+
+[source,c]
+--
+ 76         perf_evlist__enable(evlist);
+ 77         sleep(3);
+ 78         perf_evlist__disable(evlist);
+--
+
+Following code walks through the ring buffers and reads stored events/samples:
+
+[source,c]
+--
+ 80         perf_evlist__for_each_mmap(evlist, map, false) {
+ 81                 if (perf_mmap__read_init(map) < 0)
+ 82                         continue;
+ 83
+ 84                 while ((event = perf_mmap__read_event(map)) != NULL) {
+
+                            /* process event */
+
+108                         perf_mmap__consume(map);
+109                 }
+110                 perf_mmap__read_done(map);
+111         }
+
+--
+
+Each sample needs to get parsed:
+
+[source,c]
+--
+ 85                         int cpu, pid, tid;
+ 86                         __u64 ip, period, *array;
+ 87                         union u64_swap u;
+ 88
+ 89                         array = event->sample.array;
+ 90
+ 91                         ip = *array;
+ 92                         array++;
+ 93
+ 94                         u.val64 = *array;
+ 95                         pid = u.val32[0];
+ 96                         tid = u.val32[1];
+ 97                         array++;
+ 98
+ 99                         u.val64 = *array;
+100                         cpu = u.val32[0];
+101                         array++;
+102
+103                         period = *array;
+104
+105                         fprintf(stdout, "cpu %3d, pid %6d, tid %6d, ip %20llx, period %20llu\n",
+106                                 cpu, pid, tid, ip, period);
+--
+
+And finally cleanup.
+
+We close the whole events list (both events) and remove it together with the threads map:
+
+[source,c]
+--
+113 out_evlist:
+114         perf_evlist__delete(evlist);
+115 out_cpus:
+116         perf_cpu_map__put(cpus);
+117         return err;
+118 }
+--
+
+REPORTING BUGS
+--------------
+Report bugs to <linux-perf-users@vger.kernel.org>.
+
+LICENSE
+-------
+libperf is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+
+SEE ALSO
+--------
+libperf(3), libperf-counting(7)
diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
new file mode 100644
index 000000000..576ecc5fc
--- /dev/null
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -0,0 +1,253 @@
+libperf(3)
+==========
+
+NAME
+----
+libperf - Linux kernel perf event library
+
+
+SYNOPSIS
+--------
+*Generic API:*
+
+[source,c]
+--
+  #include <perf/core.h>
+
+  enum libperf_print_level {
+          LIBPERF_ERR,
+          LIBPERF_WARN,
+          LIBPERF_INFO,
+          LIBPERF_DEBUG,
+          LIBPERF_DEBUG2,
+          LIBPERF_DEBUG3,
+  };
+
+  typedef int (*libperf_print_fn_t)(enum libperf_print_level level,
+                                    const char *, va_list ap);
+
+  void libperf_init(libperf_print_fn_t fn);
+--
+
+*API to handle CPU maps:*
+
+[source,c]
+--
+  #include <perf/cpumap.h>
+
+  struct perf_cpu_map;
+
+  struct perf_cpu_map *perf_cpu_map__new_any_cpu(void);
+  struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list);
+  struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map);
+  struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
+                                           struct perf_cpu_map *other);
+  void perf_cpu_map__put(struct perf_cpu_map *map);
+  int perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx);
+  int perf_cpu_map__nr(const struct perf_cpu_map *cpus);
+  bool perf_cpu_map__has_any_cpu_or_is_empty(const struct perf_cpu_map *map);
+  int perf_cpu_map__max(struct perf_cpu_map *map);
+  bool perf_cpu_map__has(const struct perf_cpu_map *map, int cpu);
+
+  #define perf_cpu_map__for_each_cpu(cpu, idx, cpus)
+--
+
+*API to handle thread maps:*
+
+[source,c]
+--
+  #include <perf/threadmap.h>
+
+  struct perf_thread_map;
+
+  struct perf_thread_map *perf_thread_map__new_dummy(void);
+  struct perf_thread_map *perf_thread_map__new_array(int nr_threads, pid_t *array);
+
+  void perf_thread_map__set_pid(struct perf_thread_map *map, int idx, pid_t pid);
+  char *perf_thread_map__comm(struct perf_thread_map *map, int idx);
+  int perf_thread_map__nr(struct perf_thread_map *threads);
+  pid_t perf_thread_map__pid(struct perf_thread_map *map, int idx);
+
+  struct perf_thread_map *perf_thread_map__get(struct perf_thread_map *map);
+  void perf_thread_map__put(struct perf_thread_map *map);
+--
+
+*API to handle event lists:*
+
+[source,c]
+--
+  #include <perf/evlist.h>
+
+  struct perf_evlist;
+
+  void perf_evlist__add(struct perf_evlist *evlist,
+                        struct perf_evsel *evsel);
+  void perf_evlist__remove(struct perf_evlist *evlist,
+                           struct perf_evsel *evsel);
+  struct perf_evlist *perf_evlist__new(void);
+  void perf_evlist__delete(struct perf_evlist *evlist);
+  struct perf_evsel* perf_evlist__next(struct perf_evlist *evlist,
+                                       struct perf_evsel *evsel);
+  int perf_evlist__open(struct perf_evlist *evlist);
+  void perf_evlist__close(struct perf_evlist *evlist);
+  void perf_evlist__enable(struct perf_evlist *evlist);
+  void perf_evlist__disable(struct perf_evlist *evlist);
+
+  #define perf_evlist__for_each_evsel(evlist, pos)
+
+  void perf_evlist__set_maps(struct perf_evlist *evlist,
+                             struct perf_cpu_map *cpus,
+                             struct perf_thread_map *threads);
+  int perf_evlist__poll(struct perf_evlist *evlist, int timeout);
+  int perf_evlist__filter_pollfd(struct perf_evlist *evlist,
+                                 short revents_and_mask);
+
+  int perf_evlist__mmap(struct perf_evlist *evlist, int pages);
+  void perf_evlist__munmap(struct perf_evlist *evlist);
+
+  struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
+                                           struct perf_mmap *map,
+                                           bool overwrite);
+
+  #define perf_evlist__for_each_mmap(evlist, pos, overwrite)
+--
+
+*API to handle events:*
+
+[source,c]
+--
+  #include <perf/evsel.h>*
+
+  struct perf_evsel;
+
+  struct perf_counts_values {
+          union {
+                  struct {
+                          uint64_t val;
+                          uint64_t ena;
+                          uint64_t run;
+                  };
+                  uint64_t values[3];
+          };
+  };
+
+  struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr);
+  void perf_evsel__delete(struct perf_evsel *evsel);
+  int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
+                       struct perf_thread_map *threads);
+  void perf_evsel__close(struct perf_evsel *evsel);
+  void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+  int perf_evsel__mmap(struct perf_evsel *evsel, int pages);
+  void perf_evsel__munmap(struct perf_evsel *evsel);
+  void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu_map_idx, int thread);
+  int perf_evsel__read(struct perf_evsel *evsel, int cpu_map_idx, int thread,
+                       struct perf_counts_values *count);
+  int perf_evsel__enable(struct perf_evsel *evsel);
+  int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+  int perf_evsel__disable(struct perf_evsel *evsel);
+  int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+  struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
+  struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
+  struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
+--
+
+*API to handle maps (perf ring buffers):*
+
+[source,c]
+--
+  #include <perf/mmap.h>
+
+  struct perf_mmap;
+
+  void perf_mmap__consume(struct perf_mmap *map);
+  int perf_mmap__read_init(struct perf_mmap *map);
+  void perf_mmap__read_done(struct perf_mmap *map);
+  union perf_event *perf_mmap__read_event(struct perf_mmap *map);
+--
+
+*Structures to access perf API events:*
+
+[source,c]
+--
+  #include <perf/event.h>
+
+  struct perf_record_mmap;
+  struct perf_record_mmap2;
+  struct perf_record_comm;
+  struct perf_record_namespaces;
+  struct perf_record_fork;
+  struct perf_record_lost;
+  struct perf_record_lost_samples;
+  struct perf_record_read;
+  struct perf_record_throttle;
+  struct perf_record_ksymbol;
+  struct perf_record_bpf_event;
+  struct perf_record_sample;
+  struct perf_record_switch;
+  struct perf_record_header_attr;
+  struct perf_record_record_cpu_map;
+  struct perf_record_cpu_map_data;
+  struct perf_record_cpu_map;
+  struct perf_record_event_update_cpus;
+  struct perf_record_event_update_scale;
+  struct perf_record_event_update;
+  struct perf_trace_event_type;
+  struct perf_record_header_event_type;
+  struct perf_record_header_tracing_data;
+  struct perf_record_header_build_id;
+  struct perf_record_id_index;
+  struct perf_record_auxtrace_info;
+  struct perf_record_auxtrace;
+  struct perf_record_auxtrace_error;
+  struct perf_record_aux;
+  struct perf_record_itrace_start;
+  struct perf_record_thread_map_entry;
+  struct perf_record_thread_map;
+  struct perf_record_stat_config_entry;
+  struct perf_record_stat_config;
+  struct perf_record_stat;
+  struct perf_record_stat_round;
+  struct perf_record_time_conv;
+  struct perf_record_header_feature;
+  struct perf_record_compressed;
+  struct perf_record_compressed2;
+  struct perf_record_schedstat_cpu;
+  struct perf_record_schedstat_domain;
+--
+
+DESCRIPTION
+-----------
+The libperf library provides an API to access the linux kernel perf
+events subsystem.
+
+Following objects are key to the libperf interface:
+
+[horizontal]
+
+struct perf_cpu_map:: Provides a CPU list abstraction.
+
+struct perf_thread_map:: Provides a thread list abstraction.
+
+struct perf_evsel:: Provides an abstraction for single a perf event.
+
+struct perf_evlist:: Gathers several struct perf_evsel object and performs functions on all of them.
+
+struct perf_mmap:: Provides an abstraction for accessing perf ring buffer.
+
+The exported API functions bind these objects together.
+
+REPORTING BUGS
+--------------
+Report bugs to <linux-perf-users@vger.kernel.org>.
+
+LICENSE
+-------
+libperf is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+
+SEE ALSO
+--------
+libperf-sampling(7), libperf-counting(7)
diff --git a/tools/lib/perf/Documentation/manpage-1.72.xsl b/tools/lib/perf/Documentation/manpage-1.72.xsl
new file mode 100644
index 000000000..b4d315cb8
--- /dev/null
+++ b/tools/lib/perf/Documentation/manpage-1.72.xsl
@@ -0,0 +1,14 @@
+<!-- manpage-1.72.xsl:
+     special settings for manpages rendered from asciidoc+docbook
+     handles peculiarities in docbook-xsl 1.72.0 -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+		version="1.0">
+
+<xsl:import href="manpage-base.xsl"/>
+
+<!-- these are the special values for the roff control characters
+     needed for docbook-xsl 1.72.0 -->
+<xsl:param name="git.docbook.backslash">&#x2593;</xsl:param>
+<xsl:param name="git.docbook.dot"      >&#x2302;</xsl:param>
+
+</xsl:stylesheet>
diff --git a/tools/lib/perf/Documentation/manpage-base.xsl b/tools/lib/perf/Documentation/manpage-base.xsl
new file mode 100644
index 000000000..a264fa616
--- /dev/null
+++ b/tools/lib/perf/Documentation/manpage-base.xsl
@@ -0,0 +1,35 @@
+<!-- manpage-base.xsl:
+     special formatting for manpages rendered from asciidoc+docbook -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+		version="1.0">
+
+<!-- these params silence some output from xmlto -->
+<xsl:param name="man.output.quietly" select="1"/>
+<xsl:param name="refentry.meta.get.quietly" select="1"/>
+
+<!-- convert asciidoc callouts to man page format;
+     git.docbook.backslash and git.docbook.dot params
+     must be supplied by another XSL file or other means -->
+<xsl:template match="co">
+	<xsl:value-of select="concat(
+			      $git.docbook.backslash,'fB(',
+			      substring-after(@id,'-'),')',
+			      $git.docbook.backslash,'fR')"/>
+</xsl:template>
+<xsl:template match="calloutlist">
+	<xsl:value-of select="$git.docbook.dot"/>
+	<xsl:text>sp&#10;</xsl:text>
+	<xsl:apply-templates/>
+	<xsl:text>&#10;</xsl:text>
+</xsl:template>
+<xsl:template match="callout">
+	<xsl:value-of select="concat(
+			      $git.docbook.backslash,'fB',
+			      substring-after(@arearefs,'-'),
+			      '. ',$git.docbook.backslash,'fR')"/>
+	<xsl:apply-templates/>
+	<xsl:value-of select="$git.docbook.dot"/>
+	<xsl:text>br&#10;</xsl:text>
+</xsl:template>
+
+</xsl:stylesheet>
diff --git a/tools/lib/perf/Documentation/manpage-bold-literal.xsl b/tools/lib/perf/Documentation/manpage-bold-literal.xsl
new file mode 100644
index 000000000..608eb5df6
--- /dev/null
+++ b/tools/lib/perf/Documentation/manpage-bold-literal.xsl
@@ -0,0 +1,17 @@
+<!-- manpage-bold-literal.xsl:
+     special formatting for manpages rendered from asciidoc+docbook -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+		version="1.0">
+
+<!-- render literal text as bold (instead of plain or monospace);
+     this makes literal text easier to distinguish in manpages
+     viewed on a tty -->
+<xsl:template match="literal">
+	<xsl:value-of select="$git.docbook.backslash"/>
+	<xsl:text>fB</xsl:text>
+	<xsl:apply-templates/>
+	<xsl:value-of select="$git.docbook.backslash"/>
+	<xsl:text>fR</xsl:text>
+</xsl:template>
+
+</xsl:stylesheet>
diff --git a/tools/lib/perf/Documentation/manpage-normal.xsl b/tools/lib/perf/Documentation/manpage-normal.xsl
new file mode 100644
index 000000000..a48f5b11f
--- /dev/null
+++ b/tools/lib/perf/Documentation/manpage-normal.xsl
@@ -0,0 +1,13 @@
+<!-- manpage-normal.xsl:
+     special settings for manpages rendered from asciidoc+docbook
+     handles anything we want to keep away from docbook-xsl 1.72.0 -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+		version="1.0">
+
+<xsl:import href="manpage-base.xsl"/>
+
+<!-- these are the normal values for the roff control characters -->
+<xsl:param name="git.docbook.backslash">\</xsl:param>
+<xsl:param name="git.docbook.dot"	>.</xsl:param>
+
+</xsl:stylesheet>
diff --git a/tools/lib/perf/Documentation/manpage-suppress-sp.xsl b/tools/lib/perf/Documentation/manpage-suppress-sp.xsl
new file mode 100644
index 000000000..a63c7632a
--- /dev/null
+++ b/tools/lib/perf/Documentation/manpage-suppress-sp.xsl
@@ -0,0 +1,21 @@
+<!-- manpage-suppress-sp.xsl:
+     special settings for manpages rendered from asciidoc+docbook
+     handles erroneous, inline .sp in manpage output of some
+     versions of docbook-xsl -->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+		version="1.0">
+
+<!-- attempt to work around spurious .sp at the tail of the line
+     that some versions of docbook stylesheets seem to add -->
+<xsl:template match="simpara">
+  <xsl:variable name="content">
+    <xsl:apply-templates/>
+  </xsl:variable>
+  <xsl:value-of select="normalize-space($content)"/>
+  <xsl:if test="not(ancestor::authorblurb) and
+                not(ancestor::personblurb)">
+    <xsl:text>&#10;&#10;</xsl:text>
+  </xsl:if>
+</xsl:template>
+
+</xsl:stylesheet>
diff --git a/tools/lib/perf/Makefile b/tools/lib/perf/Makefile
new file mode 100644
index 000000000..32301a1d8
--- /dev/null
+++ b/tools/lib/perf/Makefile
@@ -0,0 +1,202 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+# Most of this file is copied from tools/lib/bpf/Makefile
+
+LIBPERF_VERSION = 0
+LIBPERF_PATCHLEVEL = 0
+LIBPERF_EXTRAVERSION = 1
+
+MAKEFLAGS += --no-print-directory
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+INSTALL = install
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+include $(srctree)/tools/scripts/Makefile.include
+include $(srctree)/tools/scripts/Makefile.arch
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?=
+libdir = $(prefix)/$(libdir_relative)
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
+
+TEST_ARGS := $(if $(V),-v)
+
+INCLUDES = \
+-I$(srctree)/tools/lib/perf/include \
+-I$(srctree)/tools/lib/ \
+-I$(srctree)/tools/include \
+-I$(srctree)/tools/arch/$(SRCARCH)/include/ \
+-I$(srctree)/tools/arch/$(SRCARCH)/include/uapi \
+-I$(srctree)/tools/include/uapi
+
+# Append required CFLAGS
+override CFLAGS := $(INCLUDES) $(CFLAGS)
+override CFLAGS += -g -Werror -Wall
+override CFLAGS += -fPIC
+override CFLAGS += -fvisibility=hidden
+override CFLAGS += $(EXTRA_WARNINGS)
+override CFLAGS += $(EXTRA_CFLAGS)
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+export DESTDIR DESTDIR_SQ
+
+include $(srctree)/tools/build/Makefile.include
+
+VERSION_SCRIPT := libperf.map
+
+PATCHLEVEL    = $(LIBPERF_PATCHLEVEL)
+EXTRAVERSION  = $(LIBPERF_EXTRAVERSION)
+VERSION       = $(LIBPERF_VERSION).$(LIBPERF_PATCHLEVEL).$(LIBPERF_EXTRAVERSION)
+
+LIBPERF_SO := $(OUTPUT)libperf.so.$(VERSION)
+LIBPERF_A  := $(OUTPUT)libperf.a
+LIBPERF_IN := $(OUTPUT)libperf-in.o
+LIBPERF_PC := $(OUTPUT)libperf.pc
+
+LIBPERF_ALL := $(LIBPERF_A) $(OUTPUT)libperf.so*
+
+LIB_DIR := $(srctree)/tools/lib/api/
+
+ifneq ($(OUTPUT),)
+ifneq ($(subdir),)
+  API_PATH=$(OUTPUT)/../lib/api/
+else
+  API_PATH=$(OUTPUT)
+endif
+else
+  API_PATH=$(LIB_DIR)
+endif
+
+LIBAPI = $(API_PATH)libapi.a
+export LIBAPI
+
+$(LIBAPI): FORCE
+	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) $(OUTPUT)libapi.a
+
+$(LIBAPI)-clean:
+	$(call QUIET_CLEAN, libapi)
+	$(Q)$(MAKE) -C $(LIB_DIR) O=$(OUTPUT) clean >/dev/null
+
+$(LIBPERF_IN): FORCE
+	$(Q)$(MAKE) $(build)=libperf
+
+$(LIBPERF_A): $(LIBPERF_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIBPERF_IN)
+
+$(LIBPERF_SO): $(LIBPERF_IN) $(LIBAPI)
+	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libperf.so \
+                                    -Wl,--version-script=$(VERSION_SCRIPT) $^ -o $@
+	@ln -sf $(@F) $(OUTPUT)libperf.so
+	@ln -sf $(@F) $(OUTPUT)libperf.so.$(LIBPERF_VERSION)
+
+
+libs: $(LIBPERF_A) $(LIBPERF_SO) $(LIBPERF_PC)
+
+all: fixdep
+	$(Q)$(MAKE) libs
+
+clean: $(LIBAPI)-clean
+	$(call QUIET_CLEAN, libperf) $(RM) $(LIBPERF_A) \
+                *.o *~ *.a *.so *.so.$(VERSION) *.so.$(LIBPERF_VERSION) .*.d .*.cmd tests/*.o LIBPERF-CFLAGS $(LIBPERF_PC) \
+                $(TESTS_STATIC) $(TESTS_SHARED)
+
+TESTS_IN = tests-in.o
+
+TESTS_STATIC = $(OUTPUT)tests-static
+TESTS_SHARED = $(OUTPUT)tests-shared
+
+$(TESTS_IN): FORCE
+	$(Q)$(MAKE) $(build)=tests
+
+$(TESTS_STATIC): $(TESTS_IN) $(LIBPERF_A) $(LIBAPI)
+	$(QUIET_LINK)$(CC) -o $@ $^
+
+$(TESTS_SHARED): $(TESTS_IN) $(LIBAPI)
+	$(QUIET_LINK)$(CC) -o $@ -L$(or $(OUTPUT),.) $^ -lperf
+
+make-tests: libs $(TESTS_SHARED) $(TESTS_STATIC)
+
+tests: make-tests
+	@echo "running static:"
+	@./$(TESTS_STATIC) $(TEST_ARGS)
+	@echo "running dynamic:"
+	@LD_LIBRARY_PATH=. ./$(TESTS_SHARED) $(TEST_ARGS)
+
+$(LIBPERF_PC):
+	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
+		-e "s|@LIBDIR@|$(libdir_SQ)|" \
+		-e "s|@VERSION@|$(VERSION)|" \
+		< libperf.pc.template > $@
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
+	fi
+endef
+
+define do_install
+	if [ ! -d '$2' ]; then             \
+		$(INSTALL) -d -m 755 '$2'; \
+	fi;                                \
+	$(INSTALL) $1 $(if $3,-m $3,) '$2'
+endef
+
+install_lib: libs
+	$(call QUIET_INSTALL, $(LIBPERF_ALL)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fpR $(LIBPERF_ALL) $(DESTDIR)$(libdir_SQ)
+
+HDRS := bpf_perf.h core.h cpumap.h threadmap.h evlist.h evsel.h event.h mmap.h
+HDRS += schedstat-v15.h schedstat-v16.h schedstat-v17.h
+INTERNAL_HDRS := cpumap.h evlist.h evsel.h lib.h mmap.h rc_check.h threadmap.h xyarray.h
+
+INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/perf
+INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))
+INSTALL_INTERNAL_HDRS_PFX := $(DESTDIR)$(prefix)/include/internal
+INSTALL_INTERNAL_HDRS := $(addprefix $(INSTALL_INTERNAL_HDRS_PFX)/, $(INTERNAL_HDRS))
+
+$(INSTALL_HDRS): $(INSTALL_HDRS_PFX)/%.h: include/perf/%.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/,644)
+
+$(INSTALL_INTERNAL_HDRS): $(INSTALL_INTERNAL_HDRS_PFX)/%.h: include/internal/%.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_INTERNAL_HDRS_PFX)/,644)
+
+install_headers: $(INSTALL_HDRS) $(INSTALL_INTERNAL_HDRS)
+	$(call QUIET_INSTALL, libperf_headers)
+
+install_pkgconfig: $(LIBPERF_PC)
+	$(call QUIET_INSTALL, $(LIBPERF_PC)) \
+		$(call do_install,$(LIBPERF_PC),$(DESTDIR_SQ)$(libdir_SQ)/pkgconfig,644)
+
+install_doc:
+	$(Q)$(MAKE) -C Documentation install-man install-html install-examples
+
+install: install_lib install_headers install_pkgconfig install_doc
+
+FORCE:
+
+.PHONY: all install clean tests FORCE
diff --git a/tools/lib/perf/TODO b/tools/lib/perf/TODO
new file mode 100644
index 000000000..e17972869
--- /dev/null
+++ b/tools/lib/perf/TODO
@@ -0,0 +1,30 @@
+Future ABI changes
+==================
+
+This file collects items that require a libperf ABI bump.  Each entry
+should describe the current limitation, the desired end state, and the
+scope of the change so that a future ABI revision can batch them
+together.
+
+1. Widen struct perf_cpu.cpu from int16_t to int
+   - Current limit: 32767 CPUs.  No architecture exceeds this today
+     (x86_64 max is 8192, arm64 is 4096), but NR_CPUS limits keep
+     growing.  perf clamps to INT16_MAX in set_max_cpu_num() as a
+     safety net.
+   - Code simplification: the int16_t forces defensive truncation
+     checks at every boundary where a wider CPU index (int from
+     sample->cpu, al->cpu, etc.) is narrowed into struct perf_cpu.
+     Without these checks, values > 32767 silently wrap to negative
+     numbers (two's complement), bypassing bounds validation.
+     Widening to int eliminates this entire class of silent
+     truncation bugs and removes the need for the INT16_MAX clamp
+     in set_max_cpu_num().
+   - Scope: struct perf_cpu is embedded everywhere — perf_cpu_map__cpu(),
+     perf_cpu_map__min(), perf_cpu_map__max(), perf_cpu_map__has(), the
+     for_each_cpu macros, and all internal callers.  The perf_cpu_map
+     internal array (RC_CHK_ACCESS(map)->map[]) stores struct perf_cpu
+     directly.  Widening changes the struct layout and every function
+     that returns or accepts struct perf_cpu by value.
+   - Migration: bump LIBPERF version in libperf.map, audit all
+     sizeof(struct perf_cpu) assumptions, update perf.data
+     serialization if needed.
diff --git a/tools/lib/perf/core.c b/tools/lib/perf/core.c
new file mode 100644
index 000000000..58fc894b7
--- /dev/null
+++ b/tools/lib/perf/core.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define __printf(a, b)  __attribute__((format(printf, a, b)))
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <linux/compiler.h>
+#include <perf/core.h>
+#include <internal/lib.h>
+#include "internal.h"
+
+static int __base_pr(enum libperf_print_level level __maybe_unused, const char *format,
+		     va_list args)
+{
+	return vfprintf(stderr, format, args);
+}
+
+static libperf_print_fn_t __libperf_pr = __base_pr;
+
+__printf(2, 3)
+void libperf_print(enum libperf_print_level level, const char *format, ...)
+{
+	va_list args;
+
+	if (!__libperf_pr)
+		return;
+
+	va_start(args, format);
+	__libperf_pr(level, format, args);
+	va_end(args);
+}
+
+void libperf_init(libperf_print_fn_t fn)
+{
+	page_size = sysconf(_SC_PAGE_SIZE);
+	__libperf_pr = fn;
+}
diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
new file mode 100644
index 000000000..e51b0490a
--- /dev/null
+++ b/tools/lib/perf/cpumap.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <errno.h>
+#include <perf/cpumap.h>
+#include <stdlib.h>
+#include <linux/refcount.h>
+#include <internal/cpumap.h>
+#include <asm/bug.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <limits.h>
+#include "internal.h"
+#include <api/fs/fs.h>
+
+#define MAX_NR_CPUS 4096
+
+void perf_cpu_map__set_nr(struct perf_cpu_map *map, unsigned int nr_cpus)
+{
+	RC_CHK_ACCESS(map)->nr = nr_cpus;
+}
+
+struct perf_cpu_map *perf_cpu_map__alloc(unsigned int nr_cpus)
+{
+	RC_STRUCT(perf_cpu_map) *cpus;
+	struct perf_cpu_map *result;
+
+	if (nr_cpus == 0)
+		return NULL;
+
+	cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);
+	if (ADD_RC_CHK(result, cpus)) {
+		cpus->nr = nr_cpus;
+		refcount_set(&cpus->refcnt, 1);
+	}
+	return result;
+}
+
+struct perf_cpu_map *perf_cpu_map__new_any_cpu(void)
+{
+	struct perf_cpu_map *cpus = perf_cpu_map__alloc(1);
+
+	if (cpus)
+		RC_CHK_ACCESS(cpus)->map[0].cpu = -1;
+
+	return cpus;
+}
+
+static void cpu_map__delete(struct perf_cpu_map *map)
+{
+	if (map) {
+		WARN_ONCE(refcount_read(perf_cpu_map__refcnt(map)) != 0,
+			  "cpu_map refcnt unbalanced\n");
+		RC_CHK_FREE(map);
+	}
+}
+
+struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map)
+{
+	struct perf_cpu_map *result;
+
+	if (RC_CHK_GET(result, map))
+		refcount_inc(perf_cpu_map__refcnt(map));
+
+	return result;
+}
+
+void perf_cpu_map__put(struct perf_cpu_map *map)
+{
+	if (map) {
+		if (refcount_dec_and_test(perf_cpu_map__refcnt(map)))
+			cpu_map__delete(map);
+		else
+			RC_CHK_PUT(map);
+	}
+}
+
+static struct perf_cpu_map *cpu_map__new_sysconf(void)
+{
+	struct perf_cpu_map *cpus;
+	long nr_cpus, nr_cpus_conf;
+
+	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	if (nr_cpus < 0)
+		return NULL;
+
+	nr_cpus_conf = sysconf(_SC_NPROCESSORS_CONF);
+	if (nr_cpus != nr_cpus_conf) {
+		pr_warning("Number of online CPUs (%ld) differs from the number configured (%ld) the CPU map will only cover the first %ld CPUs.",
+			nr_cpus, nr_cpus_conf, nr_cpus);
+	}
+
+	cpus = perf_cpu_map__alloc(nr_cpus);
+	if (cpus != NULL) {
+		for (long i = 0; i < nr_cpus; ++i)
+			RC_CHK_ACCESS(cpus)->map[i].cpu = i;
+	}
+
+	return cpus;
+}
+
+static struct perf_cpu_map *cpu_map__new_sysfs_online(void)
+{
+	struct perf_cpu_map *cpus = NULL;
+	char *buf = NULL;
+	size_t buf_len;
+
+	if (sysfs__read_str("devices/system/cpu/online", &buf, &buf_len) >= 0) {
+		cpus = perf_cpu_map__new(buf);
+		free(buf);
+	}
+	return cpus;
+}
+
+struct perf_cpu_map *perf_cpu_map__new_online_cpus(void)
+{
+	struct perf_cpu_map *cpus = cpu_map__new_sysfs_online();
+
+	if (cpus)
+		return cpus;
+
+	return cpu_map__new_sysconf();
+}
+
+
+static int cmp_cpu(const void *a, const void *b)
+{
+	const struct perf_cpu *cpu_a = a, *cpu_b = b;
+
+	return cpu_a->cpu - cpu_b->cpu;
+}
+
+static struct perf_cpu __perf_cpu_map__cpu(const struct perf_cpu_map *cpus, unsigned int idx)
+{
+	return RC_CHK_ACCESS(cpus)->map[idx];
+}
+
+static struct perf_cpu_map *cpu_map__trim_new(unsigned int nr_cpus, const struct perf_cpu *tmp_cpus)
+{
+	size_t payload_size = nr_cpus * sizeof(struct perf_cpu);
+	struct perf_cpu_map *cpus = perf_cpu_map__alloc(nr_cpus);
+
+	if (cpus != NULL) {
+		unsigned int j = 0;
+
+		memcpy(RC_CHK_ACCESS(cpus)->map, tmp_cpus, payload_size);
+		qsort(RC_CHK_ACCESS(cpus)->map, nr_cpus, sizeof(struct perf_cpu), cmp_cpu);
+		/* Remove dups */
+		for (unsigned int i = 0; i < nr_cpus; i++) {
+			if (i == 0 ||
+			    __perf_cpu_map__cpu(cpus, i).cpu !=
+			    __perf_cpu_map__cpu(cpus, i - 1).cpu) {
+				RC_CHK_ACCESS(cpus)->map[j++].cpu =
+					__perf_cpu_map__cpu(cpus, i).cpu;
+			}
+		}
+		perf_cpu_map__set_nr(cpus, j);
+		assert(j <= nr_cpus);
+	}
+	return cpus;
+}
+
+struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
+{
+	struct perf_cpu_map *cpus = NULL;
+	unsigned long start_cpu, end_cpu = 0;
+	char *p = NULL;
+	unsigned int nr_cpus = 0, max_entries = 0;
+	struct perf_cpu *tmp_cpus = NULL, *tmp;
+
+	if (!cpu_list)
+		return perf_cpu_map__new_online_cpus();
+
+	/*
+	 * must handle the case of empty cpumap to cover
+	 * TOPOLOGY header for NUMA nodes with no CPU
+	 * ( e.g., because of CPU hotplug)
+	 */
+	if (!isdigit(*cpu_list) && *cpu_list != '\0')
+		goto out;
+
+	while (isdigit(*cpu_list)) {
+		p = NULL;
+		start_cpu = strtoul(cpu_list, &p, 0);
+		if (start_cpu >= INT16_MAX
+		    || (*p != '\0' && *p != ',' && *p != '-' && *p != '\n'))
+			goto invalid;
+
+		if (*p == '-') {
+			cpu_list = ++p;
+			p = NULL;
+			end_cpu = strtoul(cpu_list, &p, 0);
+
+			if (end_cpu >= INT16_MAX || (*p != '\0' && *p != ',' && *p != '\n'))
+				goto invalid;
+
+			if (end_cpu < start_cpu)
+				goto invalid;
+		} else {
+			end_cpu = start_cpu;
+		}
+
+		WARN_ONCE(end_cpu >= MAX_NR_CPUS, "Perf can support %d CPUs. "
+						  "Consider raising MAX_NR_CPUS\n", MAX_NR_CPUS);
+
+		for (; start_cpu <= end_cpu; start_cpu++) {
+			/* check for duplicates */
+			for (unsigned int i = 0; i < nr_cpus; i++) {
+				if (tmp_cpus[i].cpu == (int16_t)start_cpu)
+					goto invalid;
+			}
+
+			if (nr_cpus == max_entries) {
+				max_entries += max(end_cpu - start_cpu + 1, 16UL);
+				tmp = realloc(tmp_cpus, max_entries * sizeof(struct perf_cpu));
+				if (tmp == NULL)
+					goto invalid;
+				tmp_cpus = tmp;
+			}
+			tmp_cpus[nr_cpus++].cpu = (int16_t)start_cpu;
+		}
+		if (*p)
+			++p;
+
+		cpu_list = p;
+	}
+
+	if (nr_cpus > 0) {
+		cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
+	} else if (*cpu_list != '\0') {
+		pr_warning("Unexpected characters at end of cpu list ('%s'), using online CPUs.",
+			   cpu_list);
+		cpus = perf_cpu_map__new_online_cpus();
+	} else {
+		cpus = perf_cpu_map__new_any_cpu();
+	}
+invalid:
+	free(tmp_cpus);
+out:
+	return cpus;
+}
+
+struct perf_cpu_map *perf_cpu_map__new_int(int cpu)
+{
+	struct perf_cpu_map *cpus = perf_cpu_map__alloc(1);
+
+	if (cpus)
+		RC_CHK_ACCESS(cpus)->map[0].cpu = cpu;
+
+	return cpus;
+}
+
+static unsigned int __perf_cpu_map__nr(const struct perf_cpu_map *cpus)
+{
+	return RC_CHK_ACCESS(cpus)->nr;
+}
+
+struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, unsigned int idx)
+{
+	struct perf_cpu result = {
+		.cpu = -1
+	};
+
+	if (cpus && idx < __perf_cpu_map__nr(cpus))
+		return __perf_cpu_map__cpu(cpus, idx);
+
+	return result;
+}
+
+unsigned int perf_cpu_map__nr(const struct perf_cpu_map *cpus)
+{
+	return cpus ? __perf_cpu_map__nr(cpus) : 1;
+}
+
+bool perf_cpu_map__has_any_cpu_or_is_empty(const struct perf_cpu_map *map)
+{
+	return map ? __perf_cpu_map__cpu(map, 0).cpu == -1 : true;
+}
+
+bool perf_cpu_map__is_any_cpu_or_is_empty(const struct perf_cpu_map *map)
+{
+	if (!map)
+		return true;
+
+	return __perf_cpu_map__nr(map) == 1 && __perf_cpu_map__cpu(map, 0).cpu == -1;
+}
+
+bool perf_cpu_map__is_empty(const struct perf_cpu_map *map)
+{
+	return map == NULL;
+}
+
+int perf_cpu_map__idx(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
+{
+	unsigned int low, high;
+
+	if (!cpus)
+		return -1;
+
+	low = 0;
+	high = __perf_cpu_map__nr(cpus);
+	while (low < high) {
+		int idx = (low + high) / 2;
+		struct perf_cpu cpu_at_idx = __perf_cpu_map__cpu(cpus, idx);
+
+		if (cpu_at_idx.cpu == cpu.cpu)
+			return idx;
+
+		if (cpu_at_idx.cpu > cpu.cpu)
+			high = idx;
+		else
+			low = idx + 1;
+	}
+
+	return -1;
+}
+
+bool perf_cpu_map__has(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
+{
+	return perf_cpu_map__idx(cpus, cpu) != -1;
+}
+
+bool perf_cpu_map__equal(const struct perf_cpu_map *lhs, const struct perf_cpu_map *rhs)
+{
+	unsigned int nr;
+
+	if (lhs == rhs)
+		return true;
+
+	if (!lhs || !rhs)
+		return false;
+
+	nr = __perf_cpu_map__nr(lhs);
+	if (nr != __perf_cpu_map__nr(rhs))
+		return false;
+
+	for (unsigned int idx = 0; idx < nr; idx++) {
+		if (__perf_cpu_map__cpu(lhs, idx).cpu != __perf_cpu_map__cpu(rhs, idx).cpu)
+			return false;
+	}
+	return true;
+}
+
+bool perf_cpu_map__has_any_cpu(const struct perf_cpu_map *map)
+{
+	return map && __perf_cpu_map__cpu(map, 0).cpu == -1;
+}
+
+struct perf_cpu perf_cpu_map__min(const struct perf_cpu_map *map)
+{
+	struct perf_cpu cpu, result = {
+		.cpu = -1
+	};
+	unsigned int idx;
+
+	perf_cpu_map__for_each_cpu_skip_any(cpu, idx, map) {
+		result = cpu;
+		break;
+	}
+	return result;
+}
+
+struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map)
+{
+	struct perf_cpu result = {
+		.cpu = -1
+	};
+
+	if (!map)
+		return result;
+
+	// The CPUs are always sorted and nr is always > 0 as 0 length map is
+	// encoded as NULL.
+	return __perf_cpu_map__cpu(map, __perf_cpu_map__nr(map) - 1);
+}
+
+/** Is 'b' a subset of 'a'. */
+bool perf_cpu_map__is_subset(const struct perf_cpu_map *a, const struct perf_cpu_map *b)
+{
+	if (a == b || !b)
+		return true;
+	if (!a || __perf_cpu_map__nr(b) > __perf_cpu_map__nr(a))
+		return false;
+
+	for (unsigned int i = 0, j = 0; i < __perf_cpu_map__nr(a); i++) {
+		if (__perf_cpu_map__cpu(a, i).cpu > __perf_cpu_map__cpu(b, j).cpu)
+			return false;
+		if (__perf_cpu_map__cpu(a, i).cpu == __perf_cpu_map__cpu(b, j).cpu) {
+			j++;
+			if (j == __perf_cpu_map__nr(b))
+				return true;
+		}
+	}
+	return false;
+}
+
+/*
+ * Merge two cpumaps.
+ *
+ * If 'other' is subset of '*orig', '*orig' keeps itself with no reference count
+ * change (similar to "realloc").
+ *
+ * If '*orig' is subset of 'other', '*orig' reuses 'other' with its reference
+ * count increased.
+ *
+ * Otherwise, '*orig' gets freed and replaced with a new map.
+ */
+int perf_cpu_map__merge(struct perf_cpu_map **orig, struct perf_cpu_map *other)
+{
+	struct perf_cpu *tmp_cpus;
+	unsigned int tmp_len, i, j, k;
+	struct perf_cpu_map *merged;
+
+	if (perf_cpu_map__is_subset(*orig, other))
+		return 0;
+	if (perf_cpu_map__is_subset(other, *orig)) {
+		perf_cpu_map__put(*orig);
+		*orig = perf_cpu_map__get(other);
+		return 0;
+	}
+
+	tmp_len = __perf_cpu_map__nr(*orig) + __perf_cpu_map__nr(other);
+	tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));
+	if (!tmp_cpus)
+		return -ENOMEM;
+
+	/* Standard merge algorithm from wikipedia */
+	i = j = k = 0;
+	while (i < __perf_cpu_map__nr(*orig) && j < __perf_cpu_map__nr(other)) {
+		if (__perf_cpu_map__cpu(*orig, i).cpu <= __perf_cpu_map__cpu(other, j).cpu) {
+			if (__perf_cpu_map__cpu(*orig, i).cpu == __perf_cpu_map__cpu(other, j).cpu)
+				j++;
+			tmp_cpus[k++] = __perf_cpu_map__cpu(*orig, i++);
+		} else
+			tmp_cpus[k++] = __perf_cpu_map__cpu(other, j++);
+	}
+
+	while (i < __perf_cpu_map__nr(*orig))
+		tmp_cpus[k++] = __perf_cpu_map__cpu(*orig, i++);
+
+	while (j < __perf_cpu_map__nr(other))
+		tmp_cpus[k++] = __perf_cpu_map__cpu(other, j++);
+	assert(k <= tmp_len);
+
+	merged = cpu_map__trim_new(k, tmp_cpus);
+	free(tmp_cpus);
+	perf_cpu_map__put(*orig);
+	*orig = merged;
+	return 0;
+}
+
+struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig,
+					     struct perf_cpu_map *other)
+{
+	unsigned int i, j, k;
+	struct perf_cpu_map *merged;
+
+	if (perf_cpu_map__is_subset(other, orig))
+		return perf_cpu_map__get(orig);
+	if (perf_cpu_map__is_subset(orig, other))
+		return perf_cpu_map__get(other);
+
+	i = j = k = 0;
+	while (i < __perf_cpu_map__nr(orig) && j < __perf_cpu_map__nr(other)) {
+		if (__perf_cpu_map__cpu(orig, i).cpu < __perf_cpu_map__cpu(other, j).cpu)
+			i++;
+		else if (__perf_cpu_map__cpu(orig, i).cpu > __perf_cpu_map__cpu(other, j).cpu)
+			j++;
+		else { /* CPUs match. */
+			i++;
+			j++;
+			k++;
+		}
+	}
+	if (k == 0) /* Maps are completely disjoint. */
+		return NULL;
+
+	merged = perf_cpu_map__alloc(k);
+	if (!merged)
+		return NULL;
+	/* Entries are added to merged in sorted order, so no need to sort again. */
+	i = j = k = 0;
+	while (i < __perf_cpu_map__nr(orig) && j < __perf_cpu_map__nr(other)) {
+		if (__perf_cpu_map__cpu(orig, i).cpu < __perf_cpu_map__cpu(other, j).cpu)
+			i++;
+		else if (__perf_cpu_map__cpu(orig, i).cpu > __perf_cpu_map__cpu(other, j).cpu)
+			j++;
+		else {
+			j++;
+			RC_CHK_ACCESS(merged)->map[k++] = __perf_cpu_map__cpu(orig, i++);
+		}
+	}
+	return merged;
+}
diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
new file mode 100644
index 000000000..1f210dadd
--- /dev/null
+++ b/tools/lib/perf/evlist.c
@@ -0,0 +1,840 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <perf/evlist.h>
+#include <perf/evsel.h>
+#include <linux/bitops.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <sys/ioctl.h>
+#include <internal/evlist.h>
+#include <internal/evsel.h>
+#include <internal/xyarray.h>
+#include <internal/mmap.h>
+#include <internal/cpumap.h>
+#include <internal/threadmap.h>
+#include <internal/lib.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <poll.h>
+#include <sys/mman.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <api/fd/array.h>
+#include "internal.h"
+
+void perf_evlist__init(struct perf_evlist *evlist)
+{
+	INIT_LIST_HEAD(&evlist->entries);
+	evlist->nr_entries = 0;
+	fdarray__init(&evlist->pollfd, 64);
+	perf_evlist__reset_id_hash(evlist);
+}
+
+static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
+					  struct perf_evsel *evsel)
+{
+	if (perf_cpu_map__is_empty(evsel->cpus)) {
+		if (perf_cpu_map__is_empty(evsel->pmu_cpus)) {
+			/*
+			 * Assume the unset PMU cpus were for a system-wide
+			 * event, like a software or tracepoint.
+			 */
+			evsel->pmu_cpus = perf_cpu_map__new_online_cpus();
+		}
+		if (evlist->has_user_cpus && !evsel->system_wide) {
+			/*
+			 * Use the user CPUs unless the evsel is set to be
+			 * system wide, such as the dummy event.
+			 */
+			evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
+		} else {
+			/*
+			 * System wide and other modes, assume the cpu map
+			 * should be set to all PMU CPUs.
+			 */
+			evsel->cpus = perf_cpu_map__get(evsel->pmu_cpus);
+		}
+	}
+	/*
+	 * Avoid "any CPU"(-1) for uncore and PMUs that require a CPU, even if
+	 * requested.
+	 */
+	if (evsel->requires_cpu && perf_cpu_map__has_any_cpu(evsel->cpus)) {
+		perf_cpu_map__put(evsel->cpus);
+		evsel->cpus = perf_cpu_map__get(evsel->pmu_cpus);
+	}
+
+	/*
+	 * Globally requested CPUs replace user requested unless the evsel is
+	 * set to be system wide.
+	 */
+	if (evlist->has_user_cpus && !evsel->system_wide) {
+		assert(!perf_cpu_map__has_any_cpu(evlist->user_requested_cpus));
+		if (!perf_cpu_map__equal(evsel->cpus, evlist->user_requested_cpus)) {
+			perf_cpu_map__put(evsel->cpus);
+			evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
+		}
+	}
+
+	/* Ensure cpus only references valid PMU CPUs. */
+	if (!perf_cpu_map__has_any_cpu(evsel->cpus) &&
+	    !perf_cpu_map__is_subset(evsel->pmu_cpus, evsel->cpus)) {
+		struct perf_cpu_map *tmp = perf_cpu_map__intersect(evsel->pmu_cpus, evsel->cpus);
+
+		perf_cpu_map__put(evsel->cpus);
+		evsel->cpus = tmp;
+	}
+
+	/*
+	 * Was event requested on all the PMU's CPUs but the user requested is
+	 * any CPU (-1)? If so switch to using any CPU (-1) to reduce the number
+	 * of events.
+	 */
+	if (!evsel->system_wide &&
+	    !evsel->requires_cpu &&
+	    perf_cpu_map__equal(evsel->cpus, evsel->pmu_cpus) &&
+	    perf_cpu_map__has_any_cpu(evlist->user_requested_cpus)) {
+		perf_cpu_map__put(evsel->cpus);
+		evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
+	}
+
+	/*
+	 * Tool events may only read on the first CPU index to avoid double
+	 * counting things like duration_time. Make the evsel->cpus contain just
+	 * that single entry otherwise we may spend time changing affinity to
+	 * CPUs that just have tool events, etc.
+	 */
+	if (evsel->reads_only_on_cpu_idx0 && perf_cpu_map__nr(evsel->cpus) > 0) {
+		struct perf_cpu_map *srcs[3] = {
+			evlist->all_cpus,
+			evlist->user_requested_cpus,
+			evsel->pmu_cpus,
+		};
+		for (size_t i = 0; i < ARRAY_SIZE(srcs); i++) {
+			if (!srcs[i])
+				continue;
+
+			perf_cpu_map__put(evsel->cpus);
+			evsel->cpus = perf_cpu_map__new_int(perf_cpu_map__cpu(srcs[i], 0).cpu);
+			break;
+		}
+	}
+
+	/* Sanity check assert before the evsel is potentially removed. */
+	assert(!evsel->requires_cpu || !perf_cpu_map__has_any_cpu(evsel->cpus));
+
+	/*
+	 * Empty cpu lists would eventually get opened as "any" so remove
+	 * genuinely empty ones before they're opened in the wrong place.
+	 */
+	if (perf_cpu_map__is_empty(evsel->cpus)) {
+		struct perf_evsel *next = perf_evlist__next(evlist, evsel);
+
+		perf_evlist__remove(evlist, evsel);
+		/* Keep idx contiguous */
+		if (next)
+			list_for_each_entry_from(next, &evlist->entries, node)
+				next->idx--;
+
+		return;
+	}
+
+	if (evsel->system_wide) {
+		perf_thread_map__put(evsel->threads);
+		evsel->threads = perf_thread_map__new_dummy();
+	} else {
+		perf_thread_map__put(evsel->threads);
+		evsel->threads = perf_thread_map__get(evlist->threads);
+	}
+
+	perf_cpu_map__merge(&evlist->all_cpus, evsel->cpus);
+}
+
+static void perf_evlist__propagate_maps(struct perf_evlist *evlist)
+{
+	evlist->needs_map_propagation = true;
+
+	/* Clear the all_cpus set which will be merged into during propagation. */
+	perf_cpu_map__put(evlist->all_cpus);
+	evlist->all_cpus = NULL;
+
+	/* 2 rounds so that reads_only_on_cpu_idx0 benefit from knowing the other CPU maps. */
+	for (int round = 0; round < 2; round++) {
+		struct perf_evsel *evsel, *n;
+
+		list_for_each_entry_safe(evsel, n, &evlist->entries, node) {
+			if ((!evsel->reads_only_on_cpu_idx0 && round == 0) ||
+			    (evsel->reads_only_on_cpu_idx0 && round == 1))
+				__perf_evlist__propagate_maps(evlist, evsel);
+		}
+	}
+}
+
+void perf_evlist__add(struct perf_evlist *evlist,
+		      struct perf_evsel *evsel)
+{
+	evsel->idx = evlist->nr_entries;
+	list_add_tail(&evsel->node, &evlist->entries);
+	evlist->nr_entries += 1;
+
+	if (evlist->needs_map_propagation)
+		__perf_evlist__propagate_maps(evlist, evsel);
+}
+
+void perf_evlist__remove(struct perf_evlist *evlist,
+			 struct perf_evsel *evsel)
+{
+	list_del_init(&evsel->node);
+	evlist->nr_entries -= 1;
+}
+
+struct perf_evlist *perf_evlist__new(void)
+{
+	struct perf_evlist *evlist = zalloc(sizeof(*evlist));
+
+	if (evlist != NULL)
+		perf_evlist__init(evlist);
+
+	return evlist;
+}
+
+struct perf_evsel *
+perf_evlist__next(struct perf_evlist *evlist, struct perf_evsel *prev)
+{
+	struct perf_evsel *next;
+
+	if (!prev) {
+		next = list_first_entry(&evlist->entries,
+					struct perf_evsel,
+					node);
+	} else {
+		next = list_next_entry(prev, node);
+	}
+
+	/* Empty list is noticed here so don't need checking on entry. */
+	if (&next->node == &evlist->entries)
+		return NULL;
+
+	return next;
+}
+
+static void perf_evlist__purge(struct perf_evlist *evlist)
+{
+	struct perf_evsel *pos, *n;
+
+	perf_evlist__for_each_entry_safe(evlist, n, pos) {
+		list_del_init(&pos->node);
+		perf_evsel__delete(pos);
+	}
+
+	evlist->nr_entries = 0;
+}
+
+void perf_evlist__exit(struct perf_evlist *evlist)
+{
+	perf_cpu_map__put(evlist->user_requested_cpus);
+	perf_cpu_map__put(evlist->all_cpus);
+	perf_thread_map__put(evlist->threads);
+	evlist->user_requested_cpus = NULL;
+	evlist->all_cpus = NULL;
+	evlist->threads = NULL;
+	fdarray__exit(&evlist->pollfd);
+}
+
+void perf_evlist__delete(struct perf_evlist *evlist)
+{
+	if (evlist == NULL)
+		return;
+
+	perf_evlist__munmap(evlist);
+	perf_evlist__close(evlist);
+	perf_evlist__purge(evlist);
+	perf_evlist__exit(evlist);
+	free(evlist);
+}
+
+void perf_evlist__set_maps(struct perf_evlist *evlist,
+			   struct perf_cpu_map *cpus,
+			   struct perf_thread_map *threads)
+{
+	/*
+	 * Allow for the possibility that one or another of the maps isn't being
+	 * changed i.e. don't put it.  Note we are assuming the maps that are
+	 * being applied are brand new and evlist is taking ownership of the
+	 * original reference count of 1.  If that is not the case it is up to
+	 * the caller to increase the reference count.
+	 */
+	if (cpus != evlist->user_requested_cpus) {
+		perf_cpu_map__put(evlist->user_requested_cpus);
+		evlist->user_requested_cpus = perf_cpu_map__get(cpus);
+	}
+
+	if (threads != evlist->threads) {
+		perf_thread_map__put(evlist->threads);
+		evlist->threads = perf_thread_map__get(threads);
+	}
+
+	perf_evlist__propagate_maps(evlist);
+}
+
+int perf_evlist__open(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+	int err;
+
+	perf_evlist__for_each_entry(evlist, evsel) {
+		err = perf_evsel__open(evsel, evsel->cpus, evsel->threads);
+		if (err < 0)
+			goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	perf_evlist__close(evlist);
+	return err;
+}
+
+void perf_evlist__close(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+
+	perf_evlist__for_each_entry_reverse(evlist, evsel)
+		perf_evsel__close(evsel);
+}
+
+void perf_evlist__enable(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+
+	perf_evlist__for_each_entry(evlist, evsel)
+		perf_evsel__enable(evsel);
+}
+
+void perf_evlist__disable(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+
+	perf_evlist__for_each_entry(evlist, evsel)
+		perf_evsel__disable(evsel);
+}
+
+u64 perf_evlist__read_format(struct perf_evlist *evlist)
+{
+	struct perf_evsel *first = perf_evlist__first(evlist);
+
+	return first->attr.read_format;
+}
+
+#define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
+
+static void perf_evlist__id_hash(struct perf_evlist *evlist,
+				 struct perf_evsel *evsel,
+				 int cpu_map_idx, int thread, u64 id)
+{
+	int hash;
+	struct perf_sample_id *sid = SID(evsel, cpu_map_idx, thread);
+
+	sid->id = id;
+	sid->evsel = evsel;
+	hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
+	hlist_add_head(&sid->node, &evlist->heads[hash]);
+}
+
+void perf_evlist__reset_id_hash(struct perf_evlist *evlist)
+{
+	int i;
+
+	for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
+		INIT_HLIST_HEAD(&evlist->heads[i]);
+}
+
+void perf_evlist__id_add(struct perf_evlist *evlist,
+			 struct perf_evsel *evsel,
+			 int cpu_map_idx, int thread, u64 id)
+{
+	if (!SID(evsel, cpu_map_idx, thread))
+		return;
+
+	perf_evlist__id_hash(evlist, evsel, cpu_map_idx, thread, id);
+	evsel->id[evsel->ids++] = id;
+}
+
+int perf_evlist__id_add_fd(struct perf_evlist *evlist,
+			   struct perf_evsel *evsel,
+			   int cpu_map_idx, int thread, int fd)
+{
+	u64 read_data[4] = { 0, };
+	int id_idx = 1; /* The first entry is the counter value */
+	u64 id;
+	int ret;
+
+	if (!SID(evsel, cpu_map_idx, thread))
+		return -1;
+
+	ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
+	if (!ret)
+		goto add;
+
+	if (errno != ENOTTY)
+		return -1;
+
+	/* Legacy way to get event id.. All hail to old kernels! */
+
+	/*
+	 * This way does not work with group format read, so bail
+	 * out in that case.
+	 */
+	if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
+		return -1;
+
+	if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
+	    read(fd, &read_data, sizeof(read_data)) == -1)
+		return -1;
+
+	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		++id_idx;
+	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		++id_idx;
+
+	id = read_data[id_idx];
+
+add:
+	perf_evlist__id_add(evlist, evsel, cpu_map_idx, thread, id);
+	return 0;
+}
+
+int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
+{
+	int nr_cpus = perf_cpu_map__nr(evlist->all_cpus);
+	int nr_threads = perf_thread_map__nr(evlist->threads);
+	int nfds = 0;
+	struct perf_evsel *evsel;
+
+	perf_evlist__for_each_entry(evlist, evsel) {
+		if (evsel->system_wide)
+			nfds += nr_cpus;
+		else
+			nfds += nr_cpus * nr_threads;
+	}
+
+	if (fdarray__available_entries(&evlist->pollfd) < nfds &&
+	    fdarray__grow(&evlist->pollfd, nfds) < 0)
+		return -ENOMEM;
+
+	return 0;
+}
+
+int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd,
+			    void *ptr, short revent, enum fdarray_flags flags)
+{
+	int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP, flags);
+
+	if (pos >= 0) {
+		evlist->pollfd.priv[pos].ptr = ptr;
+		fcntl(fd, F_SETFL, O_NONBLOCK);
+	}
+
+	return pos;
+}
+
+static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd,
+					 void *arg __maybe_unused)
+{
+	struct perf_mmap *map = fda->priv[fd].ptr;
+
+	if (map)
+		perf_mmap__put(map);
+}
+
+int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
+{
+	return fdarray__filter(&evlist->pollfd, revents_and_mask,
+			       perf_evlist__munmap_filtered, NULL);
+}
+
+int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
+{
+	return fdarray__poll(&evlist->pollfd, timeout);
+}
+
+static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, bool overwrite)
+{
+	int i;
+	struct perf_mmap *map;
+
+	map = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
+	if (!map)
+		return NULL;
+
+	for (i = 0; i < evlist->nr_mmaps; i++) {
+		struct perf_mmap *prev = i ? &map[i - 1] : NULL;
+
+		/*
+		 * When the perf_mmap() call is made we grab one refcount, plus
+		 * one extra to let perf_mmap__consume() get the last
+		 * events after all real references (perf_mmap__get()) are
+		 * dropped.
+		 *
+		 * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
+		 * thus does perf_mmap__get() on it.
+		 */
+		perf_mmap__init(&map[i], prev, overwrite, NULL);
+	}
+
+	return map;
+}
+
+static void perf_evsel__set_sid_idx(struct perf_evsel *evsel, int idx, int cpu, int thread)
+{
+	struct perf_sample_id *sid = SID(evsel, cpu, thread);
+
+	sid->idx = idx;
+	sid->cpu = perf_cpu_map__cpu(evsel->cpus, cpu);
+	sid->tid = perf_thread_map__pid(evsel->threads, thread);
+}
+
+static struct perf_mmap*
+perf_evlist__mmap_cb_get(struct perf_evlist *evlist, bool overwrite, int idx)
+{
+	struct perf_mmap *maps;
+
+	maps = overwrite ? evlist->mmap_ovw : evlist->mmap;
+
+	if (!maps) {
+		maps = perf_evlist__alloc_mmap(evlist, overwrite);
+		if (!maps)
+			return NULL;
+
+		if (overwrite)
+			evlist->mmap_ovw = maps;
+		else
+			evlist->mmap = maps;
+	}
+
+	return &maps[idx];
+}
+
+#define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))
+
+static int
+perf_evlist__mmap_cb_mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
+			  int output, struct perf_cpu cpu)
+{
+	return perf_mmap__mmap(map, mp, output, cpu);
+}
+
+static void perf_evlist__set_mmap_first(struct perf_evlist *evlist, struct perf_mmap *map,
+					bool overwrite)
+{
+	if (overwrite)
+		evlist->mmap_ovw_first = map;
+	else
+		evlist->mmap_first = map;
+}
+
+static int
+mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
+	       int idx, struct perf_mmap_param *mp, int cpu_idx,
+	       int thread, int *_output, int *_output_overwrite, int *nr_mmaps)
+{
+	struct perf_cpu evlist_cpu = perf_cpu_map__cpu(evlist->all_cpus, cpu_idx);
+	struct perf_evsel *evsel;
+	int revent;
+
+	perf_evlist__for_each_entry(evlist, evsel) {
+		bool overwrite = evsel->attr.write_backward;
+		enum fdarray_flags flgs;
+		struct perf_mmap *map;
+		int *output, fd, cpu;
+
+		if (evsel->system_wide && thread)
+			continue;
+
+		cpu = perf_cpu_map__idx(evsel->cpus, evlist_cpu);
+		if (cpu == -1)
+			continue;
+
+		map = ops->get(evlist, overwrite, idx);
+		if (map == NULL)
+			return -ENOMEM;
+
+		if (overwrite) {
+			mp->prot = PROT_READ;
+			output   = _output_overwrite;
+		} else {
+			mp->prot = PROT_READ | PROT_WRITE;
+			output   = _output;
+		}
+
+		fd = FD(evsel, cpu, thread);
+
+		if (*output == -1) {
+			*output = fd;
+
+			/*
+			 * The last one will be done at perf_mmap__consume(), so that we
+			 * make sure we don't prevent tools from consuming every last event in
+			 * the ring buffer.
+			 *
+			 * I.e. we can get the POLLHUP meaning that the fd doesn't exist
+			 * anymore, but the last events for it are still in the ring buffer,
+			 * waiting to be consumed.
+			 *
+			 * Tools can chose to ignore this at their own discretion, but the
+			 * evlist layer can't just drop it when filtering events in
+			 * perf_evlist__filter_pollfd().
+			 */
+			refcount_set(&map->refcnt, 2);
+
+			if (ops->idx)
+				ops->idx(evlist, evsel, mp, idx);
+
+			/* Debug message used by test scripts */
+			pr_debug("idx %d: mmapping fd %d\n", idx, *output);
+			if (ops->mmap(map, mp, *output, evlist_cpu) < 0)
+				return -1;
+
+			*nr_mmaps += 1;
+
+			if (!idx)
+				perf_evlist__set_mmap_first(evlist, map, overwrite);
+		} else {
+			/* Debug message used by test scripts */
+			pr_debug("idx %d: set output fd %d -> %d\n", idx, fd, *output);
+			if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
+				return -1;
+
+			perf_mmap__get(map);
+		}
+
+		revent = !overwrite ? POLLIN : 0;
+
+		flgs = evsel->system_wide ? fdarray_flag__nonfilterable : fdarray_flag__default;
+		if (perf_evlist__add_pollfd(evlist, fd, map, revent, flgs) < 0) {
+			perf_mmap__put(map);
+			return -1;
+		}
+
+		if (evsel->attr.read_format & PERF_FORMAT_ID) {
+			if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
+						   fd) < 0)
+				return -1;
+			perf_evsel__set_sid_idx(evsel, idx, cpu, thread);
+		}
+	}
+
+	return 0;
+}
+
+static int
+mmap_per_thread(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
+		struct perf_mmap_param *mp)
+{
+	int nr_threads = perf_thread_map__nr(evlist->threads);
+	int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
+	int cpu, thread, idx = 0;
+	int nr_mmaps = 0;
+
+	pr_debug("%s: nr cpu values (may include -1) %d nr threads %d\n",
+		 __func__, nr_cpus, nr_threads);
+
+	/* per-thread mmaps */
+	for (thread = 0; thread < nr_threads; thread++, idx++) {
+		int output = -1;
+		int output_overwrite = -1;
+
+		if (mmap_per_evsel(evlist, ops, idx, mp, 0, thread, &output,
+				   &output_overwrite, &nr_mmaps))
+			goto out_unmap;
+	}
+
+	/* system-wide mmaps i.e. per-cpu */
+	for (cpu = 1; cpu < nr_cpus; cpu++, idx++) {
+		int output = -1;
+		int output_overwrite = -1;
+
+		if (mmap_per_evsel(evlist, ops, idx, mp, cpu, 0, &output,
+				   &output_overwrite, &nr_mmaps))
+			goto out_unmap;
+	}
+
+	if (nr_mmaps != evlist->nr_mmaps)
+		pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);
+
+	return 0;
+
+out_unmap:
+	perf_evlist__munmap(evlist);
+	return -1;
+}
+
+static int
+mmap_per_cpu(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
+	     struct perf_mmap_param *mp)
+{
+	int nr_threads = perf_thread_map__nr(evlist->threads);
+	int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
+	int nr_mmaps = 0;
+	int cpu, thread;
+
+	pr_debug("%s: nr cpu values %d nr threads %d\n", __func__, nr_cpus, nr_threads);
+
+	for (cpu = 0; cpu < nr_cpus; cpu++) {
+		int output = -1;
+		int output_overwrite = -1;
+
+		for (thread = 0; thread < nr_threads; thread++) {
+			if (mmap_per_evsel(evlist, ops, cpu, mp, cpu,
+					   thread, &output, &output_overwrite, &nr_mmaps))
+				goto out_unmap;
+		}
+	}
+
+	if (nr_mmaps != evlist->nr_mmaps)
+		pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);
+
+	return 0;
+
+out_unmap:
+	perf_evlist__munmap(evlist);
+	return -1;
+}
+
+static int perf_evlist__nr_mmaps(struct perf_evlist *evlist)
+{
+	int nr_mmaps;
+
+	/* One for each CPU */
+	nr_mmaps = perf_cpu_map__nr(evlist->all_cpus);
+	if (perf_cpu_map__has_any_cpu_or_is_empty(evlist->all_cpus)) {
+		/* Plus one for each thread */
+		nr_mmaps += perf_thread_map__nr(evlist->threads);
+		/* Minus the per-thread CPU (-1) */
+		nr_mmaps -= 1;
+	}
+
+	return nr_mmaps;
+}
+
+int perf_evlist__mmap_ops(struct perf_evlist *evlist,
+			  struct perf_evlist_mmap_ops *ops,
+			  struct perf_mmap_param *mp)
+{
+	const struct perf_cpu_map *cpus = evlist->all_cpus;
+	struct perf_evsel *evsel;
+
+	if (!ops || !ops->get || !ops->mmap)
+		return -EINVAL;
+
+	mp->mask = evlist->mmap_len - page_size - 1;
+
+	evlist->nr_mmaps = perf_evlist__nr_mmaps(evlist);
+
+	perf_evlist__for_each_entry(evlist, evsel) {
+		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
+		    evsel->sample_id == NULL &&
+		    perf_evsel__alloc_id(evsel, evsel->fd->max_x, evsel->fd->max_y) < 0)
+			return -ENOMEM;
+	}
+
+	if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
+		return -ENOMEM;
+
+	if (perf_cpu_map__has_any_cpu_or_is_empty(cpus))
+		return mmap_per_thread(evlist, ops, mp);
+
+	return mmap_per_cpu(evlist, ops, mp);
+}
+
+int perf_evlist__mmap(struct perf_evlist *evlist, int pages)
+{
+	struct perf_mmap_param mp;
+	struct perf_evlist_mmap_ops ops = {
+		.get  = perf_evlist__mmap_cb_get,
+		.mmap = perf_evlist__mmap_cb_mmap,
+	};
+
+	evlist->mmap_len = (pages + 1) * page_size;
+
+	return perf_evlist__mmap_ops(evlist, &ops, &mp);
+}
+
+void perf_evlist__munmap(struct perf_evlist *evlist)
+{
+	int i;
+
+	if (evlist->mmap) {
+		for (i = 0; i < evlist->nr_mmaps; i++)
+			perf_mmap__munmap(&evlist->mmap[i]);
+	}
+
+	if (evlist->mmap_ovw) {
+		for (i = 0; i < evlist->nr_mmaps; i++)
+			perf_mmap__munmap(&evlist->mmap_ovw[i]);
+	}
+
+	zfree(&evlist->mmap);
+	zfree(&evlist->mmap_ovw);
+}
+
+struct perf_mmap*
+perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
+		       bool overwrite)
+{
+	if (map)
+		return map->next;
+
+	return overwrite ? evlist->mmap_ovw_first : evlist->mmap_first;
+}
+
+void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader)
+{
+	struct perf_evsel *evsel;
+	int n = 0;
+
+	__perf_evlist__for_each_entry(list, evsel) {
+		evsel->leader = leader;
+		n++;
+	}
+	leader->nr_members = n;
+}
+
+void perf_evlist__set_leader(struct perf_evlist *evlist)
+{
+	if (evlist->nr_entries) {
+		struct perf_evsel *first = list_entry(evlist->entries.next,
+						struct perf_evsel, node);
+
+		__perf_evlist__set_leader(&evlist->entries, first);
+	}
+}
+
+int perf_evlist__nr_groups(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+	int nr_groups = 0;
+
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		/*
+		 * evsels by default have a nr_members of 1, and they are their
+		 * own leader. If the nr_members is >1 then this is an
+		 * indication of a group.
+		 */
+		if (evsel->leader == evsel && evsel->nr_members > 1)
+			nr_groups++;
+	}
+	return nr_groups;
+}
+
+void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *evsel)
+{
+	if (!evsel->system_wide) {
+		evsel->system_wide = true;
+		if (evlist->needs_map_propagation)
+			__perf_evlist__propagate_maps(evlist, evsel);
+	}
+}
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
new file mode 100644
index 000000000..f747c0bc6
--- /dev/null
+++ b/tools/lib/perf/evsel.c
@@ -0,0 +1,618 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <perf/evsel.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <linux/hash.h>
+#include <linux/list.h>
+#include <internal/evsel.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <internal/xyarray.h>
+#include <internal/cpumap.h>
+#include <internal/mmap.h>
+#include <internal/threadmap.h>
+#include <internal/lib.h>
+#include <linux/string.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <asm/bug.h>
+
+void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
+		      int idx)
+{
+	INIT_LIST_HEAD(&evsel->node);
+	INIT_LIST_HEAD(&evsel->per_stream_periods);
+	evsel->attr = *attr;
+	evsel->idx  = idx;
+	evsel->leader = evsel;
+}
+
+struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr)
+{
+	struct perf_evsel *evsel = zalloc(sizeof(*evsel));
+
+	if (evsel != NULL)
+		perf_evsel__init(evsel, attr, 0);
+
+	return evsel;
+}
+
+void perf_evsel__exit(struct perf_evsel *evsel)
+{
+	assert(evsel->fd == NULL);  /* If not fds were not closed. */
+	assert(evsel->mmap == NULL); /* If not munmap wasn't called. */
+	assert(evsel->sample_id == NULL); /* If not free_id wasn't called. */
+	perf_cpu_map__put(evsel->cpus);
+	perf_cpu_map__put(evsel->pmu_cpus);
+	perf_thread_map__put(evsel->threads);
+}
+
+void perf_evsel__delete(struct perf_evsel *evsel)
+{
+	perf_evsel__exit(evsel);
+	free(evsel);
+}
+
+#define FD(_evsel, _cpu_map_idx, _thread)				\
+	((int *)xyarray__entry(_evsel->fd, _cpu_map_idx, _thread))
+#define MMAP(_evsel, _cpu_map_idx, _thread)				\
+	(_evsel->mmap ? ((struct perf_mmap *) xyarray__entry(_evsel->mmap, _cpu_map_idx, _thread)) \
+		      : NULL)
+
+int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
+{
+	evsel->fd = xyarray__new(ncpus, nthreads, sizeof(int));
+
+	if (evsel->fd) {
+		int idx, thread;
+
+		for (idx = 0; idx < ncpus; idx++) {
+			for (thread = 0; thread < nthreads; thread++) {
+				int *fd = FD(evsel, idx, thread);
+
+				if (fd)
+					*fd = -1;
+			}
+		}
+	}
+
+	return evsel->fd != NULL ? 0 : -ENOMEM;
+}
+
+static int perf_evsel__alloc_mmap(struct perf_evsel *evsel, int ncpus, int nthreads)
+{
+	evsel->mmap = xyarray__new(ncpus, nthreads, sizeof(struct perf_mmap));
+
+	return evsel->mmap != NULL ? 0 : -ENOMEM;
+}
+
+static int
+sys_perf_event_open(struct perf_event_attr *attr,
+		    pid_t pid, struct perf_cpu cpu, int group_fd,
+		    unsigned long flags)
+{
+	return syscall(__NR_perf_event_open, attr, pid, cpu.cpu, group_fd, flags);
+}
+
+static int get_group_fd(struct perf_evsel *evsel, int cpu_map_idx, int thread, int *group_fd)
+{
+	struct perf_evsel *leader = evsel->leader;
+	int *fd;
+
+	if (evsel == leader) {
+		*group_fd = -1;
+		return 0;
+	}
+
+	/*
+	 * Leader must be already processed/open,
+	 * if not it's a bug.
+	 */
+	if (!leader->fd)
+		return -ENOTCONN;
+
+	fd = FD(leader, cpu_map_idx, thread);
+	if (fd == NULL || *fd == -1)
+		return -EBADF;
+
+	*group_fd = *fd;
+
+	return 0;
+}
+
+int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
+		     struct perf_thread_map *threads)
+{
+	struct perf_cpu cpu;
+	unsigned int idx;
+	int thread, err = 0;
+
+	if (cpus == NULL) {
+		static struct perf_cpu_map *empty_cpu_map;
+
+		if (empty_cpu_map == NULL) {
+			empty_cpu_map = perf_cpu_map__new_any_cpu();
+			if (empty_cpu_map == NULL)
+				return -ENOMEM;
+		}
+
+		cpus = empty_cpu_map;
+	}
+
+	if (threads == NULL) {
+		static struct perf_thread_map *empty_thread_map;
+
+		if (empty_thread_map == NULL) {
+			empty_thread_map = perf_thread_map__new_dummy();
+			if (empty_thread_map == NULL)
+				return -ENOMEM;
+		}
+
+		threads = empty_thread_map;
+	}
+
+	if (evsel->fd == NULL &&
+	    perf_evsel__alloc_fd(evsel, perf_cpu_map__nr(cpus), threads->nr) < 0)
+		return -ENOMEM;
+
+	perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
+		for (thread = 0; thread < threads->nr; thread++) {
+			int fd, group_fd, *evsel_fd;
+
+			evsel_fd = FD(evsel, idx, thread);
+			if (evsel_fd == NULL) {
+				err = -EINVAL;
+				goto out;
+			}
+
+			err = get_group_fd(evsel, idx, thread, &group_fd);
+			if (err < 0)
+				goto out;
+
+			fd = sys_perf_event_open(&evsel->attr,
+						 threads->map[thread].pid,
+						 cpu, group_fd, 0);
+
+			if (fd < 0) {
+				err = -errno;
+				goto out;
+			}
+
+			*evsel_fd = fd;
+		}
+	}
+out:
+	if (err)
+		perf_evsel__close(evsel);
+
+	return err;
+}
+
+static void perf_evsel__close_fd_cpu(struct perf_evsel *evsel, int cpu_map_idx)
+{
+	int thread;
+
+	for (thread = 0; thread < xyarray__max_y(evsel->fd); ++thread) {
+		int *fd = FD(evsel, cpu_map_idx, thread);
+
+		if (fd && *fd >= 0) {
+			close(*fd);
+			*fd = -1;
+		}
+	}
+}
+
+void perf_evsel__close_fd(struct perf_evsel *evsel)
+{
+	for (int idx = 0; idx < xyarray__max_x(evsel->fd); idx++)
+		perf_evsel__close_fd_cpu(evsel, idx);
+}
+
+void perf_evsel__free_fd(struct perf_evsel *evsel)
+{
+	xyarray__delete(evsel->fd);
+	evsel->fd = NULL;
+}
+
+void perf_evsel__close(struct perf_evsel *evsel)
+{
+	if (evsel->fd == NULL)
+		return;
+
+	perf_evsel__close_fd(evsel);
+	perf_evsel__free_fd(evsel);
+}
+
+void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu_map_idx)
+{
+	if (evsel->fd == NULL)
+		return;
+
+	perf_evsel__close_fd_cpu(evsel, cpu_map_idx);
+}
+
+void perf_evsel__munmap(struct perf_evsel *evsel)
+{
+	int idx, thread;
+
+	if (evsel->fd == NULL || evsel->mmap == NULL)
+		return;
+
+	for (idx = 0; idx < xyarray__max_x(evsel->fd); idx++) {
+		for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) {
+			int *fd = FD(evsel, idx, thread);
+
+			if (fd == NULL || *fd < 0)
+				continue;
+
+			perf_mmap__munmap(MMAP(evsel, idx, thread));
+		}
+	}
+
+	xyarray__delete(evsel->mmap);
+	evsel->mmap = NULL;
+}
+
+int perf_evsel__mmap(struct perf_evsel *evsel, int pages)
+{
+	int ret, idx, thread;
+	struct perf_mmap_param mp = {
+		.prot = PROT_READ | PROT_WRITE,
+		.mask = (pages * page_size) - 1,
+	};
+
+	if (evsel->fd == NULL || evsel->mmap)
+		return -EINVAL;
+
+	if (perf_evsel__alloc_mmap(evsel, xyarray__max_x(evsel->fd), xyarray__max_y(evsel->fd)) < 0)
+		return -ENOMEM;
+
+	for (idx = 0; idx < xyarray__max_x(evsel->fd); idx++) {
+		for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) {
+			int *fd = FD(evsel, idx, thread);
+			struct perf_mmap *map;
+			struct perf_cpu cpu = perf_cpu_map__cpu(evsel->cpus, idx);
+
+			if (fd == NULL || *fd < 0)
+				continue;
+
+			map = MMAP(evsel, idx, thread);
+			perf_mmap__init(map, NULL, false, NULL);
+
+			ret = perf_mmap__mmap(map, &mp, *fd, cpu);
+			if (ret) {
+				perf_evsel__munmap(evsel);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu_map_idx, int thread)
+{
+	int *fd = FD(evsel, cpu_map_idx, thread);
+
+	if (fd == NULL || *fd < 0 || MMAP(evsel, cpu_map_idx, thread) == NULL)
+		return NULL;
+
+	return MMAP(evsel, cpu_map_idx, thread)->base;
+}
+
+int perf_evsel__read_size(struct perf_evsel *evsel)
+{
+	u64 read_format = evsel->attr.read_format;
+	int entry = sizeof(u64); /* value */
+	int size = 0;
+	int nr = 1;
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		size += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		size += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_ID)
+		entry += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_LOST)
+		entry += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_GROUP) {
+		nr = evsel->nr_members;
+		size += sizeof(u64);
+	}
+
+	size += entry * nr;
+	return size;
+}
+
+/* This only reads values for the leader */
+static int perf_evsel__read_group(struct perf_evsel *evsel, int cpu_map_idx,
+				  int thread, struct perf_counts_values *count)
+{
+	size_t size = perf_evsel__read_size(evsel);
+	int *fd = FD(evsel, cpu_map_idx, thread);
+	u64 read_format = evsel->attr.read_format;
+	u64 *data;
+	int idx = 1;
+
+	if (fd == NULL || *fd < 0)
+		return -EINVAL;
+
+	data = calloc(1, size);
+	if (data == NULL)
+		return -ENOMEM;
+
+	if (readn(*fd, data, size) <= 0) {
+		free(data);
+		return -errno;
+	}
+
+	/*
+	 * This reads only the leader event intentionally since we don't have
+	 * perf counts values for sibling events.
+	 */
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		count->ena = data[idx++];
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		count->run = data[idx++];
+
+	/* value is always available */
+	count->val = data[idx++];
+	if (read_format & PERF_FORMAT_ID)
+		count->id = data[idx++];
+	if (read_format & PERF_FORMAT_LOST)
+		count->lost = data[idx++];
+
+	free(data);
+	return 0;
+}
+
+/*
+ * The perf read format is very flexible.  It needs to set the proper
+ * values according to the read format.
+ */
+static void perf_evsel__adjust_values(struct perf_evsel *evsel, u64 *buf,
+				      struct perf_counts_values *count)
+{
+	u64 read_format = evsel->attr.read_format;
+	int n = 0;
+
+	count->val = buf[n++];
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		count->ena = buf[n++];
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		count->run = buf[n++];
+
+	if (read_format & PERF_FORMAT_ID)
+		count->id = buf[n++];
+
+	if (read_format & PERF_FORMAT_LOST)
+		count->lost = buf[n++];
+}
+
+int perf_evsel__read(struct perf_evsel *evsel, int cpu_map_idx, int thread,
+		     struct perf_counts_values *count)
+{
+	size_t size = perf_evsel__read_size(evsel);
+	int *fd = FD(evsel, cpu_map_idx, thread);
+	u64 read_format = evsel->attr.read_format;
+	struct perf_counts_values buf;
+
+	memset(count, 0, sizeof(*count));
+
+	if (fd == NULL || *fd < 0)
+		return -EINVAL;
+
+	if (read_format & PERF_FORMAT_GROUP)
+		return perf_evsel__read_group(evsel, cpu_map_idx, thread, count);
+
+	if (MMAP(evsel, cpu_map_idx, thread) &&
+	    !(read_format & (PERF_FORMAT_ID | PERF_FORMAT_LOST)) &&
+	    !perf_mmap__read_self(MMAP(evsel, cpu_map_idx, thread), count))
+		return 0;
+
+	if (readn(*fd, buf.values, size) <= 0)
+		return -errno;
+
+	perf_evsel__adjust_values(evsel, buf.values, count);
+	return 0;
+}
+
+static int perf_evsel__ioctl(struct perf_evsel *evsel, int ioc, void *arg,
+			     int cpu_map_idx, int thread)
+{
+	int *fd = FD(evsel, cpu_map_idx, thread);
+
+	if (fd == NULL || *fd < 0)
+		return -1;
+
+	return ioctl(*fd, ioc, arg);
+}
+
+static int perf_evsel__run_ioctl(struct perf_evsel *evsel,
+				 int ioc,  void *arg,
+				 int cpu_map_idx)
+{
+	int thread;
+
+	for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) {
+		int err = perf_evsel__ioctl(evsel, ioc, arg, cpu_map_idx, thread);
+
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx)
+{
+	return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, NULL, cpu_map_idx);
+}
+
+int perf_evsel__enable_thread(struct perf_evsel *evsel, int thread)
+{
+	struct perf_cpu cpu __maybe_unused;
+	unsigned int idx;
+	int err;
+
+	perf_cpu_map__for_each_cpu(cpu, idx, evsel->cpus) {
+		err = perf_evsel__ioctl(evsel, PERF_EVENT_IOC_ENABLE, NULL, idx, thread);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+int perf_evsel__enable(struct perf_evsel *evsel)
+{
+	int i;
+	int err = 0;
+
+	for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++)
+		err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, NULL, i);
+	return err;
+}
+
+int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx)
+{
+	return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_DISABLE, NULL, cpu_map_idx);
+}
+
+int perf_evsel__disable(struct perf_evsel *evsel)
+{
+	int i;
+	int err = 0;
+
+	for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++)
+		err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_DISABLE, NULL, i);
+	return err;
+}
+
+int perf_evsel__apply_filter(struct perf_evsel *evsel, const char *filter)
+{
+	int err = 0;
+
+	for (unsigned int i = 0; i < perf_cpu_map__nr(evsel->cpus) && !err; i++) {
+		err = perf_evsel__run_ioctl(evsel,
+				     PERF_EVENT_IOC_SET_FILTER,
+				     (void *)filter, i);
+	}
+	return err;
+}
+
+struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel)
+{
+	return evsel->cpus;
+}
+
+struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel)
+{
+	return evsel->threads;
+}
+
+struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel)
+{
+	return &evsel->attr;
+}
+
+int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads)
+{
+	if (ncpus == 0 || nthreads == 0)
+		return 0;
+
+	evsel->sample_id = xyarray__new(ncpus, nthreads, sizeof(struct perf_sample_id));
+	if (evsel->sample_id == NULL)
+		return -ENOMEM;
+
+	evsel->id = zalloc(ncpus * nthreads * sizeof(u64));
+	if (evsel->id == NULL) {
+		xyarray__delete(evsel->sample_id);
+		evsel->sample_id = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+void perf_evsel__free_id(struct perf_evsel *evsel)
+{
+	struct perf_sample_id_period *pos, *n;
+
+	xyarray__delete(evsel->sample_id);
+	evsel->sample_id = NULL;
+	zfree(&evsel->id);
+	evsel->ids = 0;
+
+	perf_evsel_for_each_per_thread_period_safe(evsel, n, pos) {
+		list_del_init(&pos->node);
+		free(pos);
+	}
+}
+
+bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel)
+{
+	return (evsel->attr.sample_type & PERF_SAMPLE_READ) &&
+		(evsel->attr.sample_type & PERF_SAMPLE_TID) &&
+		evsel->attr.inherit;
+}
+
+u64 *perf_sample_id__get_period_storage(struct perf_sample_id *sid, u32 tid, bool per_thread)
+{
+	struct hlist_head *head;
+	struct perf_sample_id_period *res;
+	int hash;
+
+	if (!per_thread)
+		return &sid->period;
+
+	hash = hash_32(tid, PERF_SAMPLE_ID__HLIST_BITS);
+	head = &sid->periods[hash];
+
+	hlist_for_each_entry(res, head, hnode)
+		if (res->tid == tid)
+			return &res->period;
+
+	if (sid->evsel == NULL)
+		return NULL;
+
+	res = zalloc(sizeof(struct perf_sample_id_period));
+	if (res == NULL)
+		return NULL;
+
+	INIT_LIST_HEAD(&res->node);
+	res->tid = tid;
+
+	list_add_tail(&res->node, &sid->evsel->per_stream_periods);
+	hlist_add_head(&res->hnode, &sid->periods[hash]);
+
+	return &res->period;
+}
+
+void perf_counts_values__scale(struct perf_counts_values *count,
+			       bool scale, __s8 *pscaled)
+{
+	s8 scaled = 0;
+
+	if (scale) {
+		if (count->run == 0) {
+			scaled = -1;
+			count->val = 0;
+		} else if (count->run < count->ena) {
+			scaled = 1;
+			count->val = (u64)((double)count->val * count->ena / count->run);
+		}
+	}
+
+	if (pscaled)
+		*pscaled = scaled;
+}
diff --git a/tools/lib/perf/include/internal/cpumap.h b/tools/lib/perf/include/internal/cpumap.h
new file mode 100644
index 000000000..c19678188
--- /dev/null
+++ b/tools/lib/perf/include/internal/cpumap.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_CPUMAP_H
+#define __LIBPERF_INTERNAL_CPUMAP_H
+
+#include <linux/refcount.h>
+#include <perf/cpumap.h>
+#include <internal/rc_check.h>
+
+/**
+ * A sized, reference counted, sorted array of integers representing CPU
+ * numbers. This is commonly used to capture which CPUs a PMU is associated
+ * with. The indices into the cpumap are frequently used as they avoid having
+ * gaps if CPU numbers were used. For events associated with a pid, rather than
+ * a CPU, a single dummy map with an entry of -1 is used.
+ */
+DECLARE_RC_STRUCT(perf_cpu_map) {
+	refcount_t	refcnt;
+	/** Length of the map array. */
+	unsigned int	nr;
+	/** The CPU values. */
+	struct perf_cpu	map[];
+};
+
+struct perf_cpu_map *perf_cpu_map__alloc(unsigned int nr_cpus);
+int perf_cpu_map__idx(const struct perf_cpu_map *cpus, struct perf_cpu cpu);
+bool perf_cpu_map__is_subset(const struct perf_cpu_map *a, const struct perf_cpu_map *b);
+
+void perf_cpu_map__set_nr(struct perf_cpu_map *map, unsigned int nr_cpus);
+
+static inline refcount_t *perf_cpu_map__refcnt(struct perf_cpu_map *map)
+{
+	return &RC_CHK_ACCESS(map)->refcnt;
+}
+#endif /* __LIBPERF_INTERNAL_CPUMAP_H */
diff --git a/tools/lib/perf/include/internal/evlist.h b/tools/lib/perf/include/internal/evlist.h
new file mode 100644
index 000000000..f43bdb9b6
--- /dev/null
+++ b/tools/lib/perf/include/internal/evlist.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_EVLIST_H
+#define __LIBPERF_INTERNAL_EVLIST_H
+
+#include <linux/list.h>
+#include <api/fd/array.h>
+#include <internal/cpumap.h>
+#include <internal/evsel.h>
+
+#define PERF_EVLIST__HLIST_BITS 8
+#define PERF_EVLIST__HLIST_SIZE (1 << PERF_EVLIST__HLIST_BITS)
+
+struct perf_cpu_map;
+struct perf_thread_map;
+struct perf_mmap_param;
+
+struct perf_evlist {
+	struct list_head	 entries;
+	int			 nr_entries;
+	bool			 has_user_cpus;
+	bool			 needs_map_propagation;
+	/**
+	 * The cpus passed from the command line or all online CPUs by
+	 * default.
+	 */
+	struct perf_cpu_map	*user_requested_cpus;
+	/** The union of all evsel cpu maps. */
+	struct perf_cpu_map	*all_cpus;
+	struct perf_thread_map	*threads;
+	int			 nr_mmaps;
+	size_t			 mmap_len;
+	struct fdarray		 pollfd;
+	struct hlist_head	 heads[PERF_EVLIST__HLIST_SIZE];
+	struct perf_mmap	*mmap;
+	struct perf_mmap	*mmap_ovw;
+	struct perf_mmap	*mmap_first;
+	struct perf_mmap	*mmap_ovw_first;
+};
+
+typedef void
+(*perf_evlist_mmap__cb_idx_t)(struct perf_evlist*, struct perf_evsel*,
+			      struct perf_mmap_param*, int);
+typedef struct perf_mmap*
+(*perf_evlist_mmap__cb_get_t)(struct perf_evlist*, bool, int);
+typedef int
+(*perf_evlist_mmap__cb_mmap_t)(struct perf_mmap*, struct perf_mmap_param*, int, struct perf_cpu);
+
+struct perf_evlist_mmap_ops {
+	perf_evlist_mmap__cb_idx_t	idx;
+	perf_evlist_mmap__cb_get_t	get;
+	perf_evlist_mmap__cb_mmap_t	mmap;
+};
+
+int perf_evlist__alloc_pollfd(struct perf_evlist *evlist);
+int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd,
+			    void *ptr, short revent, enum fdarray_flags flags);
+
+int perf_evlist__mmap_ops(struct perf_evlist *evlist,
+			  struct perf_evlist_mmap_ops *ops,
+			  struct perf_mmap_param *mp);
+
+void perf_evlist__init(struct perf_evlist *evlist);
+void perf_evlist__exit(struct perf_evlist *evlist);
+
+/**
+ * __perf_evlist__for_each_entry - iterate thru all the evsels
+ * @list: list_head instance to iterate
+ * @evsel: struct perf_evsel iterator
+ */
+#define __perf_evlist__for_each_entry(list, evsel) \
+	list_for_each_entry(evsel, list, node)
+
+/**
+ * evlist__for_each_entry - iterate thru all the evsels
+ * @evlist: perf_evlist instance to iterate
+ * @evsel: struct perf_evsel iterator
+ */
+#define perf_evlist__for_each_entry(evlist, evsel) \
+	__perf_evlist__for_each_entry(&(evlist)->entries, evsel)
+
+/**
+ * __perf_evlist__for_each_entry_reverse - iterate thru all the evsels in reverse order
+ * @list: list_head instance to iterate
+ * @evsel: struct evsel iterator
+ */
+#define __perf_evlist__for_each_entry_reverse(list, evsel) \
+	list_for_each_entry_reverse(evsel, list, node)
+
+/**
+ * perf_evlist__for_each_entry_reverse - iterate thru all the evsels in reverse order
+ * @evlist: evlist instance to iterate
+ * @evsel: struct evsel iterator
+ */
+#define perf_evlist__for_each_entry_reverse(evlist, evsel) \
+	__perf_evlist__for_each_entry_reverse(&(evlist)->entries, evsel)
+
+/**
+ * __perf_evlist__for_each_entry_safe - safely iterate thru all the evsels
+ * @list: list_head instance to iterate
+ * @tmp: struct evsel temp iterator
+ * @evsel: struct evsel iterator
+ */
+#define __perf_evlist__for_each_entry_safe(list, tmp, evsel) \
+	list_for_each_entry_safe(evsel, tmp, list, node)
+
+/**
+ * perf_evlist__for_each_entry_safe - safely iterate thru all the evsels
+ * @evlist: evlist instance to iterate
+ * @evsel: struct evsel iterator
+ * @tmp: struct evsel temp iterator
+ */
+#define perf_evlist__for_each_entry_safe(evlist, tmp, evsel) \
+	__perf_evlist__for_each_entry_safe(&(evlist)->entries, tmp, evsel)
+
+static inline struct perf_evsel *perf_evlist__first(struct perf_evlist *evlist)
+{
+	return list_entry(evlist->entries.next, struct perf_evsel, node);
+}
+
+static inline struct perf_evsel *perf_evlist__last(struct perf_evlist *evlist)
+{
+	return list_entry(evlist->entries.prev, struct perf_evsel, node);
+}
+
+u64 perf_evlist__read_format(struct perf_evlist *evlist);
+
+void perf_evlist__id_add(struct perf_evlist *evlist,
+			 struct perf_evsel *evsel,
+			 int cpu_map_idx, int thread, u64 id);
+
+int perf_evlist__id_add_fd(struct perf_evlist *evlist,
+			   struct perf_evsel *evsel,
+			   int cpu_map_idx, int thread, int fd);
+
+void perf_evlist__reset_id_hash(struct perf_evlist *evlist);
+
+void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader);
+
+void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *evsel);
+#endif /* __LIBPERF_INTERNAL_EVLIST_H */
diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h
new file mode 100644
index 000000000..b988034f1
--- /dev/null
+++ b/tools/lib/perf/include/internal/evsel.h
@@ -0,0 +1,153 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_EVSEL_H
+#define __LIBPERF_INTERNAL_EVSEL_H
+
+#include <linux/types.h>
+#include <linux/perf_event.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <internal/cpumap.h>
+
+struct perf_thread_map;
+struct xyarray;
+
+/**
+ * The per-thread accumulated period storage node.
+ */
+struct perf_sample_id_period {
+	struct list_head	node;
+	struct hlist_node	hnode;
+	/* Holds total ID period value for PERF_SAMPLE_READ processing. */
+	u64			period;
+	/* The TID that the values belongs to */
+	u32			tid;
+};
+
+/**
+ * perf_evsel_for_each_per_thread_period_safe - safely iterate thru all the
+ * per_stream_periods
+ * @evlist:perf_evsel instance to iterate
+ * @item: struct perf_sample_id_period iterator
+ * @tmp: struct perf_sample_id_period temp iterator
+ */
+#define perf_evsel_for_each_per_thread_period_safe(evsel, tmp, item) \
+	list_for_each_entry_safe(item, tmp, &(evsel)->per_stream_periods, node)
+
+
+#define PERF_SAMPLE_ID__HLIST_BITS 4
+#define PERF_SAMPLE_ID__HLIST_SIZE (1 << PERF_SAMPLE_ID__HLIST_BITS)
+
+/*
+ * Per fd, to map back from PERF_SAMPLE_ID to evsel, only used when there are
+ * more than one entry in the evlist.
+ */
+struct perf_sample_id {
+	struct hlist_node	 node;
+	u64			 id;
+	struct perf_evsel	*evsel;
+       /*
+	* 'idx' will be used for AUX area sampling. A sample will have AUX area
+	* data that will be queued for decoding, where there are separate
+	* queues for each CPU (per-cpu tracing) or task (per-thread tracing).
+	* The sample ID can be used to lookup 'idx' which is effectively the
+	* queue number.
+	*/
+	int			 idx;
+	struct perf_cpu		 cpu;
+	pid_t			 tid;
+
+	/* Guest machine pid and VCPU, valid only if machine_pid is non-zero */
+	pid_t			 machine_pid;
+	struct perf_cpu		 vcpu;
+
+	/*
+	 * Per-thread, and global event counts are mutually exclusive:
+	 * Whilst it is possible to combine events into a group with differing
+	 * values of PERF_SAMPLE_READ, it is not valid to have inconsistent
+	 * values for `inherit`. Therefore it is not possible to have a
+	 * situation where a per-thread event is sampled as a global event;
+	 * all !inherit groups are global, and all groups where the sampling
+	 * event is inherit + PERF_SAMPLE_READ will be per-thread. Any event
+	 * that is part of such a group that is inherit but not PERF_SAMPLE_READ
+	 * will be read as per-thread. If such an event can also trigger a
+	 * sample (such as with sample_period > 0) then it will not cause
+	 * `read_format` to be included in its PERF_RECORD_SAMPLE, and
+	 * therefore will not expose the per-thread group members as global.
+	 */
+	union {
+		/*
+		 * Holds total ID period value for PERF_SAMPLE_READ processing
+		 * (when period is not per-thread).
+		 */
+		u64			period;
+		/*
+		 * Holds total ID period value for PERF_SAMPLE_READ processing
+		 * (when period is per-thread).
+		 */
+		struct hlist_head	periods[PERF_SAMPLE_ID__HLIST_SIZE];
+	};
+};
+
+struct perf_evsel {
+	struct list_head	 node;
+	struct perf_event_attr	 attr;
+	/** The commonly used cpu map of CPUs the event should be opened upon, etc. */
+	struct perf_cpu_map	*cpus;
+	/**
+	 * The cpu map read from the PMU. For core PMUs this is the list of all
+	 * CPUs the event can be opened upon. For other PMUs this is the default
+	 * cpu map for opening the event on, for example, the first CPU on a
+	 * socket for an uncore event.
+	 */
+	struct perf_cpu_map	*pmu_cpus;
+	struct perf_thread_map	*threads;
+	struct xyarray		*fd;
+	struct xyarray		*mmap;
+	struct xyarray		*sample_id;
+	u64			*id;
+	u32			 ids;
+	struct perf_evsel	*leader;
+
+	/* For events where the read_format value is per-thread rather than
+	 * global, stores the per-thread cumulative period */
+	struct list_head	per_stream_periods;
+
+	/* parse modifier helper */
+	int			 nr_members;
+	/*
+	 * system_wide is for events that need to be on every CPU, irrespective
+	 * of user requested CPUs or threads. Tha main example of this is the
+	 * dummy event. Map propagation will set cpus for this event to all CPUs
+	 * as software PMU events like dummy, have a CPU map that is empty.
+	 */
+	bool			 system_wide;
+	/*
+	 * Some events, for example uncore events, require a CPU.
+	 * i.e. it cannot be the 'any CPU' value of -1.
+	 */
+	bool			 requires_cpu;
+	/** Is the PMU for the event a core one? Effects the handling of own_cpus. */
+	bool			 is_pmu_core;
+	/** Does the evsel on read on the first CPU index such as tool time events? */
+	bool			 reads_only_on_cpu_idx0;
+	int			 idx;
+};
+
+void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
+		      int idx);
+void perf_evsel__exit(struct perf_evsel *evsel);
+int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
+void perf_evsel__close_fd(struct perf_evsel *evsel);
+void perf_evsel__free_fd(struct perf_evsel *evsel);
+int perf_evsel__read_size(struct perf_evsel *evsel);
+int perf_evsel__apply_filter(struct perf_evsel *evsel, const char *filter);
+
+int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads);
+void perf_evsel__free_id(struct perf_evsel *evsel);
+
+bool perf_evsel__attr_has_per_thread_sample_period(struct perf_evsel *evsel);
+
+u64 *perf_sample_id__get_period_storage(struct perf_sample_id *sid, u32 tid,
+					bool per_thread);
+
+#endif /* __LIBPERF_INTERNAL_EVSEL_H */
diff --git a/tools/lib/perf/include/internal/lib.h b/tools/lib/perf/include/internal/lib.h
new file mode 100644
index 000000000..85471a4b9
--- /dev/null
+++ b/tools/lib/perf/include/internal/lib.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_LIB_H
+#define __LIBPERF_INTERNAL_LIB_H
+
+#include <sys/types.h>
+
+extern unsigned int page_size;
+
+ssize_t readn(int fd, void *buf, size_t n);
+ssize_t writen(int fd, const void *buf, size_t n);
+
+ssize_t preadn(int fd, void *buf, size_t n, off_t offs);
+
+#endif /* __LIBPERF_INTERNAL_CPUMAP_H */
diff --git a/tools/lib/perf/include/internal/mmap.h b/tools/lib/perf/include/internal/mmap.h
new file mode 100644
index 000000000..5f08cab61
--- /dev/null
+++ b/tools/lib/perf/include/internal/mmap.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_MMAP_H
+#define __LIBPERF_INTERNAL_MMAP_H
+
+#include <linux/compiler.h>
+#include <linux/refcount.h>
+#include <linux/types.h>
+#include <stdbool.h>
+#include <internal/cpumap.h>
+
+/* perf sample has 16 bits size limit */
+#define PERF_SAMPLE_MAX_SIZE (1 << 16)
+
+struct perf_mmap;
+struct perf_counts_values;
+
+typedef void (*libperf_unmap_cb_t)(struct perf_mmap *map);
+
+/**
+ * struct perf_mmap - perf's ring buffer mmap details
+ *
+ * @refcnt - e.g. code using PERF_EVENT_IOC_SET_OUTPUT to share this
+ */
+struct perf_mmap {
+	void			*base;
+	int			 mask;
+	int			 fd;
+	struct perf_cpu		 cpu;
+	refcount_t		 refcnt;
+	u64			 prev;
+	u64			 start;
+	u64			 end;
+	bool			 overwrite;
+	u64			 flush;
+	libperf_unmap_cb_t	 unmap_cb;
+	void			*event_copy;
+	size_t			 event_copy_sz;
+	struct perf_mmap	*next;
+};
+
+struct perf_mmap_param {
+	int	prot;
+	int	mask;
+};
+
+size_t perf_mmap__mmap_len(struct perf_mmap *map);
+
+void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
+		     bool overwrite, libperf_unmap_cb_t unmap_cb);
+int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
+		    int fd, struct perf_cpu cpu);
+void perf_mmap__munmap(struct perf_mmap *map);
+void perf_mmap__get(struct perf_mmap *map);
+void perf_mmap__put(struct perf_mmap *map);
+
+u64 perf_mmap__read_head(struct perf_mmap *map);
+
+int perf_mmap__read_self(struct perf_mmap *map, struct perf_counts_values *count);
+
+#endif /* __LIBPERF_INTERNAL_MMAP_H */
diff --git a/tools/lib/perf/include/internal/rc_check.h b/tools/lib/perf/include/internal/rc_check.h
new file mode 100644
index 000000000..f80ddfc80
--- /dev/null
+++ b/tools/lib/perf/include/internal/rc_check.h
@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __LIBPERF_INTERNAL_RC_CHECK_H
+#define __LIBPERF_INTERNAL_RC_CHECK_H
+
+#include <stdlib.h>
+#include <linux/zalloc.h>
+
+/*
+ * Enable reference count checking implicitly with leak checking, which is
+ * integrated into address sanitizer.
+ */
+#if defined(__SANITIZE_ADDRESS__) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER)
+#define REFCNT_CHECKING 1
+#elif defined(__has_feature)
+#if __has_feature(address_sanitizer) || __has_feature(leak_sanitizer)
+#define REFCNT_CHECKING 1
+#endif
+#endif
+
+/*
+ * Shared reference count checking macros.
+ *
+ * Reference count checking is an approach to sanitizing the use of reference
+ * counted structs. It leverages address and leak sanitizers to make sure gets
+ * are paired with a put. Reference count checking adds a malloc-ed layer of
+ * indirection on a get, and frees it on a put. A missed put will be reported as
+ * a memory leak. A double put will be reported as a double free. Accessing
+ * after a put will cause a use-after-free and/or a segfault.
+ */
+
+#ifndef REFCNT_CHECKING
+/* Replaces "struct foo" so that the pointer may be interposed. */
+#define DECLARE_RC_STRUCT(struct_name)		\
+	struct struct_name
+
+/* Declare a reference counted struct variable. */
+#define RC_STRUCT(struct_name) struct struct_name
+
+/*
+ * Interpose the indirection. Result will hold the indirection and object is the
+ * reference counted struct.
+ */
+#define ADD_RC_CHK(result, object) (result = object, object)
+
+/* Strip the indirection layer. */
+#define RC_CHK_ACCESS(object) object
+
+/* Frees the object and the indirection layer. */
+#define RC_CHK_FREE(object) free(object)
+
+/* A get operation adding the indirection layer. */
+#define RC_CHK_GET(result, object) ADD_RC_CHK(result, object)
+
+/* A put operation removing the indirection layer. */
+#define RC_CHK_PUT(object) {}
+
+/* Pointer equality when the indirection may or may not be there. */
+#define RC_CHK_EQUAL(object1, object2) (object1 == object2)
+
+#else
+
+/* Replaces "struct foo" so that the pointer may be interposed. */
+#define DECLARE_RC_STRUCT(struct_name)			\
+	struct original_##struct_name;			\
+	struct struct_name {				\
+		struct original_##struct_name *orig;	\
+	};						\
+	struct original_##struct_name
+
+/* Declare a reference counted struct variable. */
+#define RC_STRUCT(struct_name) struct original_##struct_name
+
+/*
+ * Interpose the indirection. Result will hold the indirection and object is the
+ * reference counted struct.
+ */
+#define ADD_RC_CHK(result, object)					\
+	(								\
+		object ? (result = malloc(sizeof(*result)),		\
+			result ? (result->orig = object, result)	\
+			: (result = NULL, NULL))			\
+		: (result = NULL, NULL)					\
+		)
+
+/* Strip the indirection layer. */
+#define RC_CHK_ACCESS(object) object->orig
+
+/* Frees the object and the indirection layer. */
+#define RC_CHK_FREE(object)			\
+	do {					\
+		zfree(&object->orig);		\
+		free(object);			\
+	} while(0)
+
+/* A get operation adding the indirection layer. */
+#define RC_CHK_GET(result, object) ADD_RC_CHK(result, (object ? object->orig : NULL))
+
+/* A put operation removing the indirection layer. */
+#define RC_CHK_PUT(object)			\
+	do {					\
+		if (object) {			\
+			object->orig = NULL;	\
+			free(object);		\
+		}				\
+	} while(0)
+
+/* Pointer equality when the indirection may or may not be there. */
+#define RC_CHK_EQUAL(object1, object2) (object1 == object2 || \
+		(object1 && object2 && object1->orig == object2->orig))
+
+#endif
+
+#endif /* __LIBPERF_INTERNAL_RC_CHECK_H */
diff --git a/tools/lib/perf/include/internal/tests.h b/tools/lib/perf/include/internal/tests.h
new file mode 100644
index 000000000..b130a6663
--- /dev/null
+++ b/tools/lib/perf/include/internal/tests.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_TESTS_H
+#define __LIBPERF_INTERNAL_TESTS_H
+
+#include <stdio.h>
+#include <unistd.h>
+
+extern int tests_failed;
+extern int tests_verbose;
+
+static inline int get_verbose(char **argv, int argc)
+{
+	int c;
+	int verbose = 0;
+
+	while ((c = getopt(argc, argv, "v")) != -1) {
+		switch (c)
+		{
+		case 'v':
+			verbose = 1;
+			break;
+		default:
+			break;
+		}
+	}
+	optind = 1;
+
+	return verbose;
+}
+
+#define __T_START					\
+do {							\
+	tests_verbose = get_verbose(argv, argc);	\
+	fprintf(stdout, "- running %s...", __FILE__);	\
+	fflush(NULL);					\
+	tests_failed = 0;				\
+} while (0)
+
+#define __T_END								\
+do {									\
+	if (tests_failed)						\
+		fprintf(stdout, "  FAILED (%d)\n", tests_failed);	\
+	else								\
+		fprintf(stdout, "OK\n");				\
+} while (0)
+
+#define __T(text, cond)                                                          \
+do {                                                                             \
+	if (!(cond)) {                                                           \
+		fprintf(stderr, "FAILED %s:%d %s\n", __FILE__, __LINE__, text);  \
+		tests_failed++;                                                  \
+		return -1;                                                       \
+	}                                                                        \
+} while (0)
+
+#define __T_VERBOSE(...)						\
+do {									\
+	if (tests_verbose) {						\
+		if (tests_verbose == 1) {				\
+			fputc('\n', stderr);				\
+			tests_verbose++;				\
+		}							\
+		fprintf(stderr, ##__VA_ARGS__);				\
+	}								\
+} while (0)
+
+#endif /* __LIBPERF_INTERNAL_TESTS_H */
diff --git a/tools/lib/perf/include/internal/threadmap.h b/tools/lib/perf/include/internal/threadmap.h
new file mode 100644
index 000000000..df748baf9
--- /dev/null
+++ b/tools/lib/perf/include/internal/threadmap.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_THREADMAP_H
+#define __LIBPERF_INTERNAL_THREADMAP_H
+
+#include <linux/refcount.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+struct thread_map_data {
+	pid_t	 pid;
+	char	*comm;
+};
+
+struct perf_thread_map {
+	refcount_t	refcnt;
+	int		nr;
+	int		err_thread;
+	struct thread_map_data map[];
+};
+
+struct perf_thread_map *perf_thread_map__realloc(struct perf_thread_map *map, int nr);
+
+#endif /* __LIBPERF_INTERNAL_THREADMAP_H */
diff --git a/tools/lib/perf/include/internal/xyarray.h b/tools/lib/perf/include/internal/xyarray.h
new file mode 100644
index 000000000..f10af3da7
--- /dev/null
+++ b/tools/lib/perf/include/internal/xyarray.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_XYARRAY_H
+#define __LIBPERF_INTERNAL_XYARRAY_H
+
+#include <linux/compiler.h>
+#include <sys/types.h>
+
+struct xyarray {
+	size_t row_size;
+	size_t entry_size;
+	size_t entries;
+	size_t max_x;
+	size_t max_y;
+	char contents[] __aligned(8);
+};
+
+struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size);
+void xyarray__delete(struct xyarray *xy);
+void xyarray__reset(struct xyarray *xy);
+
+static inline void *__xyarray__entry(struct xyarray *xy, int x, int y)
+{
+	return &xy->contents[x * xy->row_size + y * xy->entry_size];
+}
+
+static inline void *xyarray__entry(struct xyarray *xy, size_t x, size_t y)
+{
+	if (x >= xy->max_x || y >= xy->max_y)
+		return NULL;
+	return __xyarray__entry(xy, x, y);
+}
+
+static inline int xyarray__max_y(struct xyarray *xy)
+{
+	return xy->max_y;
+}
+
+static inline int xyarray__max_x(struct xyarray *xy)
+{
+	return xy->max_x;
+}
+
+#endif /* __LIBPERF_INTERNAL_XYARRAY_H */
diff --git a/tools/lib/perf/include/perf/bpf_perf.h b/tools/lib/perf/include/perf/bpf_perf.h
new file mode 100644
index 000000000..e7cf6ba7b
--- /dev/null
+++ b/tools/lib/perf/include/perf/bpf_perf.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __LIBPERF_BPF_PERF_H
+#define __LIBPERF_BPF_PERF_H
+
+#include <linux/types.h>  /* for __u32 */
+
+/*
+ * bpf_perf uses a hashmap, the attr_map, to track all the leader programs.
+ * The hashmap is pinned in bpffs. flock() on this file is used to ensure
+ * no concurrent access to the attr_map.  The key of attr_map is struct
+ * perf_event_attr, and the value is struct perf_event_attr_map_entry.
+ *
+ * struct perf_event_attr_map_entry contains two __u32 IDs, bpf_link of the
+ * leader prog, and the diff_map. Each perf-stat session holds a reference
+ * to the bpf_link to make sure the leader prog is attached to sched_switch
+ * tracepoint.
+ *
+ * Since the hashmap only contains IDs of the bpf_link and diff_map, it
+ * does not hold any references to the leader program. Once all perf-stat
+ * sessions of these events exit, the leader prog, its maps, and the
+ * perf_events will be freed.
+ */
+struct perf_event_attr_map_entry {
+	__u32 link_id;
+	__u32 diff_map_id;
+};
+
+/* default attr_map name */
+#define BPF_PERF_DEFAULT_ATTR_MAP_PATH "perf_attr_map"
+
+#endif /* __LIBPERF_BPF_PERF_H */
diff --git a/tools/lib/perf/include/perf/core.h b/tools/lib/perf/include/perf/core.h
new file mode 100644
index 000000000..06cc132d8
--- /dev/null
+++ b/tools/lib/perf/include/perf/core.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_CORE_H
+#define __LIBPERF_CORE_H
+
+#include <stdarg.h>
+
+#ifndef LIBPERF_API
+#define LIBPERF_API extern __attribute__((visibility("default")))
+#endif
+
+enum libperf_print_level {
+	LIBPERF_ERR,
+	LIBPERF_WARN,
+	LIBPERF_INFO,
+	LIBPERF_DEBUG,
+	LIBPERF_DEBUG2,
+	LIBPERF_DEBUG3,
+};
+
+typedef int (*libperf_print_fn_t)(enum libperf_print_level level,
+				  const char *, va_list ap);
+
+LIBPERF_API void libperf_init(libperf_print_fn_t fn);
+
+#endif /* __LIBPERF_CORE_H */
diff --git a/tools/lib/perf/include/perf/cpumap.h b/tools/lib/perf/include/perf/cpumap.h
new file mode 100644
index 000000000..e1a0b0d27
--- /dev/null
+++ b/tools/lib/perf/include/perf/cpumap.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_CPUMAP_H
+#define __LIBPERF_CPUMAP_H
+
+#include <perf/core.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+/**
+ * struct perf_cpu - wrapper around a CPU number.
+ * @cpu: CPU number, -1 for the "any CPU"/dummy value.
+ *
+ * int16_t limits this to 32767 CPUs.  Widening to int requires a libperf
+ * ABI bump — see tools/lib/perf/TODO for the full scope.
+ */
+struct perf_cpu {
+	int16_t cpu;
+};
+
+struct perf_cache {
+	int cache_lvl;
+	int cache;
+};
+
+struct perf_cpu_map;
+
+/**
+ * perf_cpu_map__new_any_cpu - a map with a singular "any CPU"/dummy -1 value.
+ */
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__new_any_cpu(void);
+/**
+ * perf_cpu_map__new_online_cpus - a map read from
+ *                                 /sys/devices/system/cpu/online if
+ *                                 available. If reading wasn't possible a map
+ *                                 is created using the online processors
+ *                                 assuming the first 'n' processors are all
+ *                                 online.
+ */
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__new_online_cpus(void);
+/**
+ * perf_cpu_map__new - create a map from the given cpu_list such as "0-7". If no
+ *                     cpu_list argument is provided then
+ *                     perf_cpu_map__new_online_cpus is returned.
+ */
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list);
+/** perf_cpu_map__new_int - create a map with the one given cpu. */
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__new_int(int cpu);
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map);
+LIBPERF_API int perf_cpu_map__merge(struct perf_cpu_map **orig,
+				    struct perf_cpu_map *other);
+LIBPERF_API struct perf_cpu_map *perf_cpu_map__intersect(struct perf_cpu_map *orig,
+							 struct perf_cpu_map *other);
+LIBPERF_API void perf_cpu_map__put(struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__cpu - get the CPU value at the given index. Returns -1 if index
+ *                     is invalid.
+ */
+LIBPERF_API struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, unsigned int idx);
+/**
+ * perf_cpu_map__nr - for an empty map returns 1, as perf_cpu_map__cpu returns a
+ *                    cpu of -1 for an invalid index, this makes an empty map
+ *                    look like it contains the "any CPU"/dummy value. Otherwise
+ *                    the result is the number CPUs in the map plus one if the
+ *                    "any CPU"/dummy value is present.
+ */
+LIBPERF_API unsigned int perf_cpu_map__nr(const struct perf_cpu_map *cpus);
+/**
+ * perf_cpu_map__has_any_cpu_or_is_empty - is map either empty or has the "any CPU"/dummy value.
+ */
+LIBPERF_API bool perf_cpu_map__has_any_cpu_or_is_empty(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__is_any_cpu_or_is_empty - is map either empty or the "any CPU"/dummy value.
+ */
+LIBPERF_API bool perf_cpu_map__is_any_cpu_or_is_empty(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__is_empty - does the map contain no values and it doesn't
+ *                          contain the special "any CPU"/dummy value.
+ */
+LIBPERF_API bool perf_cpu_map__is_empty(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__min - the minimum CPU value or -1 if empty or just the "any CPU"/dummy value.
+ */
+LIBPERF_API struct perf_cpu perf_cpu_map__min(const struct perf_cpu_map *map);
+/**
+ * perf_cpu_map__max - the maximum CPU value or -1 if empty or just the "any CPU"/dummy value.
+ */
+LIBPERF_API struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map);
+LIBPERF_API bool perf_cpu_map__has(const struct perf_cpu_map *map, struct perf_cpu cpu);
+LIBPERF_API bool perf_cpu_map__equal(const struct perf_cpu_map *lhs,
+				     const struct perf_cpu_map *rhs);
+/**
+ * perf_cpu_map__any_cpu - Does the map contain the "any CPU"/dummy -1 value?
+ */
+LIBPERF_API bool perf_cpu_map__has_any_cpu(const struct perf_cpu_map *map);
+
+#define perf_cpu_map__for_each_cpu(cpu, idx, cpus)		\
+	for ((idx) = 0, (cpu) = perf_cpu_map__cpu(cpus, idx);	\
+	     (idx) < perf_cpu_map__nr(cpus);			\
+	     (idx)++, (cpu) = perf_cpu_map__cpu(cpus, idx))
+
+#define perf_cpu_map__for_each_cpu_skip_any(_cpu, idx, cpus)	\
+	for ((idx) = 0, (_cpu) = perf_cpu_map__cpu(cpus, idx);	\
+	     (idx) < perf_cpu_map__nr(cpus);			\
+	     (idx)++, (_cpu) = perf_cpu_map__cpu(cpus, idx))	\
+		if ((_cpu).cpu != -1)
+
+#define perf_cpu_map__for_each_idx(idx, cpus)				\
+	for ((idx) = 0; (idx) < perf_cpu_map__nr(cpus); (idx)++)
+
+#endif /* __LIBPERF_CPUMAP_H */
diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
new file mode 100644
index 000000000..fdced574c
--- /dev/null
+++ b/tools/lib/perf/include/perf/event.h
@@ -0,0 +1,643 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_EVENT_H
+#define __LIBPERF_EVENT_H
+
+#include <linux/perf_event.h>
+#include <linux/types.h>
+#include <linux/limits.h>
+#include <linux/bpf.h>
+#include <sys/types.h> /* pid_t */
+
+/*
+ * Verify the full field fits within the event, not just its start offset.
+ * Only valid for fixed-size scalar fields — for trailing arrays like
+ * filename[PATH_MAX], sizeof() evaluates to the declared maximum, not
+ * the actual string length, so this would spuriously return false.
+ */
+#define event_contains(obj, mem) \
+	((obj).header.size >= offsetof(typeof(obj), mem) + sizeof((obj).mem))
+
+struct perf_record_mmap {
+	struct perf_event_header header;
+	__u32			 pid, tid;
+	__u64			 start;
+	__u64			 len;
+	__u64			 pgoff;
+	char			 filename[PATH_MAX];
+};
+
+struct perf_record_mmap2 {
+	struct perf_event_header header;
+	__u32			 pid, tid;
+	__u64			 start;
+	__u64			 len;
+	__u64			 pgoff;
+	union {
+		struct {
+			__u32	 maj;
+			__u32	 min;
+			__u64	 ino;
+			__u64	 ino_generation;
+		};
+		struct {
+			__u8	 build_id_size;
+			__u8	 __reserved_1;
+			__u16	 __reserved_2;
+			__u8	 build_id[20];
+		};
+	};
+	__u32			 prot;
+	__u32			 flags;
+	char			 filename[PATH_MAX];
+};
+
+struct perf_record_comm {
+	struct perf_event_header header;
+	__u32			 pid, tid;
+	char			 comm[16];
+};
+
+struct perf_record_namespaces {
+	struct perf_event_header header;
+	__u32			 pid, tid;
+	__u64			 nr_namespaces;
+	struct perf_ns_link_info link_info[];
+};
+
+struct perf_record_fork {
+	struct perf_event_header header;
+	__u32			 pid, ppid;
+	__u32			 tid, ptid;
+	__u64			 time;
+};
+
+struct perf_record_lost {
+	struct perf_event_header header;
+	__u64			 id;
+	__u64			 lost;
+};
+
+#define PERF_RECORD_MISC_LOST_SAMPLES_BPF (1 << 15)
+
+struct perf_record_lost_samples {
+	struct perf_event_header header;
+	__u64			 lost;
+};
+
+#define MAX_ID_HDR_ENTRIES  6
+struct perf_record_lost_samples_and_ids {
+	struct perf_record_lost_samples lost;
+	__u64 sample_ids[MAX_ID_HDR_ENTRIES];
+};
+
+/*
+ * PERF_FORMAT_ENABLED | PERF_FORMAT_RUNNING | PERF_FORMAT_ID | PERF_FORMAT_LOST
+ */
+struct perf_record_read {
+	struct perf_event_header header;
+	__u32			 pid, tid;
+	__u64			 value;
+	__u64			 time_enabled;
+	__u64			 time_running;
+	__u64			 id;
+	__u64			 lost;
+};
+
+struct perf_record_throttle {
+	struct perf_event_header header;
+	__u64			 time;
+	__u64			 id;
+	__u64			 stream_id;
+};
+
+#ifndef KSYM_NAME_LEN
+#define KSYM_NAME_LEN 512
+#endif
+
+struct perf_record_ksymbol {
+	struct perf_event_header header;
+	__u64			 addr;
+	__u32			 len;
+	__u16			 ksym_type;
+	__u16			 flags;
+	char			 name[KSYM_NAME_LEN];
+};
+
+struct perf_record_bpf_event {
+	struct perf_event_header header;
+	__u16			 type;
+	__u16			 flags;
+	__u32			 id;
+
+	/* for bpf_prog types */
+	__u8			 tag[BPF_TAG_SIZE];  // prog tag
+};
+
+struct perf_record_cgroup {
+	struct perf_event_header header;
+	__u64			 id;
+	char			 path[PATH_MAX];
+};
+
+struct perf_record_text_poke_event {
+	struct perf_event_header header;
+	__u64			addr;
+	__u16			old_len;
+	__u16			new_len;
+	__u8			bytes[];
+};
+
+struct perf_record_sample {
+	struct perf_event_header header;
+	__u64			 array[];
+};
+
+struct perf_record_switch {
+	struct perf_event_header header;
+	__u32			 next_prev_pid;
+	__u32			 next_prev_tid;
+};
+
+struct perf_record_callchain_deferred {
+	struct perf_event_header header;
+	/*
+	 * This is to match kernel and (deferred) user stacks together.
+	 * The kernel part will be in the sample callchain array after
+	 * the PERF_CONTEXT_USER_DEFERRED entry.
+	 */
+	__u64			 cookie;
+	__u64			 nr;
+	__u64			 ips[];
+};
+
+struct perf_record_header_attr {
+	struct perf_event_header header;
+	struct perf_event_attr	 attr;
+	/*
+	 * Array of u64 id follows here but we cannot use a flexible array
+	 * because size of attr in the data can be different then current
+	 * version.  Please use perf_record_header_attr_id() below.
+	 *
+	 * __u64		 id[];  // do not use this
+	 */
+};
+
+/* Returns the pointer to id array based on the actual attr size. */
+#define perf_record_header_attr_id(evt)			\
+	((void *)&(evt)->attr.attr + (evt)->attr.attr.size)
+
+enum {
+	PERF_CPU_MAP__CPUS = 0,
+	PERF_CPU_MAP__MASK = 1,
+	PERF_CPU_MAP__RANGE_CPUS = 2,
+};
+
+/*
+ * Array encoding of a perf_cpu_map where nr is the number of entries in cpu[]
+ * and each entry is a value for a CPU in the map.
+ */
+struct cpu_map_entries {
+	__u16			 nr;
+	__u16			 cpu[];
+};
+
+/* Bitmap encoding of a perf_cpu_map where bitmap entries are 32-bit. */
+struct perf_record_mask_cpu_map32 {
+	/* Number of mask values. */
+	__u16			 nr;
+	/* Constant 4. */
+	__u16			 long_size;
+	/* Bitmap data. */
+	__u32			 mask[];
+};
+
+/* Bitmap encoding of a perf_cpu_map where bitmap entries are 64-bit. */
+struct perf_record_mask_cpu_map64 {
+	/* Number of mask values. */
+	__u16			 nr;
+	/* Constant 8. */
+	__u16			 long_size;
+	/* Legacy padding. */
+	char                     __pad[4];
+	/* Bitmap data. */
+	__u64			 mask[];
+};
+
+/*
+ * 'struct perf_record_cpu_map_data' is packed as unfortunately an earlier
+ * version had unaligned data and we wish to retain file format compatibility.
+ * -irogers
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpacked"
+#pragma GCC diagnostic ignored "-Wattributes"
+
+/*
+ * An encoding of a CPU map for a range starting at start_cpu through to
+ * end_cpu. If any_cpu is 1, an any CPU (-1) value (aka dummy value) is present.
+ */
+struct perf_record_range_cpu_map {
+	__u8 any_cpu;
+	__u8 __pad;
+	__u16 start_cpu;
+	__u16 end_cpu;
+};
+
+struct perf_record_cpu_map_data {
+	__u16			 type;
+	union {
+		/* Used when type == PERF_CPU_MAP__CPUS. */
+		struct cpu_map_entries cpus_data;
+		/* Used when type == PERF_CPU_MAP__MASK and long_size == 4. */
+		struct perf_record_mask_cpu_map32 mask32_data;
+		/* Used when type == PERF_CPU_MAP__MASK and long_size == 8. */
+		struct perf_record_mask_cpu_map64 mask64_data;
+		/* Used when type == PERF_CPU_MAP__RANGE_CPUS. */
+		struct perf_record_range_cpu_map range_cpu_data;
+	};
+} __attribute__((packed));
+
+#pragma GCC diagnostic pop
+
+struct perf_record_cpu_map {
+	struct perf_event_header	 header;
+	struct perf_record_cpu_map_data	 data;
+};
+
+enum {
+	PERF_EVENT_UPDATE__UNIT  = 0,
+	PERF_EVENT_UPDATE__SCALE = 1,
+	PERF_EVENT_UPDATE__NAME  = 2,
+	PERF_EVENT_UPDATE__CPUS  = 3,
+};
+
+struct perf_record_event_update_cpus {
+	struct perf_record_cpu_map_data	 cpus;
+};
+
+struct perf_record_event_update_scale {
+	double			 scale;
+};
+
+struct perf_record_event_update {
+	struct perf_event_header header;
+	__u64			 type;
+	__u64			 id;
+	union {
+		/* Used when type == PERF_EVENT_UPDATE__SCALE. */
+		struct perf_record_event_update_scale scale;
+		/* Used when type == PERF_EVENT_UPDATE__UNIT. */
+		char unit[0];
+		/* Used when type == PERF_EVENT_UPDATE__NAME. */
+		char name[0];
+		/* Used when type == PERF_EVENT_UPDATE__CPUS. */
+		struct perf_record_event_update_cpus cpus;
+	};
+};
+
+#define MAX_EVENT_NAME 64
+
+struct perf_trace_event_type {
+	__u64			 event_id;
+	char			 name[MAX_EVENT_NAME];
+};
+
+struct perf_record_header_event_type {
+	struct perf_event_header	 header;
+	struct perf_trace_event_type	 event_type;
+};
+
+struct perf_record_header_tracing_data {
+	struct perf_event_header header;
+	__u32			 size;
+	__u32			 pad;
+};
+
+#define PERF_RECORD_MISC_BUILD_ID_SIZE (1 << 15)
+
+struct perf_record_header_build_id {
+	struct perf_event_header header;
+	pid_t			 pid;
+	union {
+		__u8		 build_id[24];
+		struct {
+			__u8	 data[20];
+			__u8	 size;
+			__u8	 reserved1__;
+			__u16	 reserved2__;
+		};
+	};
+	char			 filename[];
+};
+
+struct id_index_entry {
+	__u64			 id;
+	__u64			 idx;
+	__u64			 cpu;
+	__u64			 tid;
+};
+
+struct id_index_entry_2 {
+	__u64			 machine_pid;
+	__u64			 vcpu;
+};
+
+struct perf_record_id_index {
+	struct perf_event_header header;
+	__u64			 nr;
+	struct id_index_entry	 entries[];
+};
+
+struct perf_record_auxtrace_info {
+	struct perf_event_header header;
+	__u32			 type;
+	__u32			 reserved__; /* For alignment */
+	__u64			 priv[];
+};
+
+struct perf_record_auxtrace {
+	struct perf_event_header header;
+	__u64			 size;
+	__u64			 offset;
+	__u64			 reference;
+	__u32			 idx;
+	__u32			 tid;
+	__u32			 cpu;
+	__u32			 reserved__; /* For alignment */
+};
+
+#define MAX_AUXTRACE_ERROR_MSG 64
+
+struct perf_record_auxtrace_error {
+	struct perf_event_header header;
+	__u32			 type;
+	__u32			 code;
+	__u32			 cpu;
+	__u32			 pid;
+	__u32			 tid;
+	__u32			 fmt;
+	__u64			 ip;
+	__u64			 time;
+	char			 msg[MAX_AUXTRACE_ERROR_MSG];
+	__u32			 machine_pid;
+	__u32			 vcpu;
+};
+
+struct perf_record_aux {
+	struct perf_event_header header;
+	__u64			 aux_offset;
+	__u64			 aux_size;
+	__u64			 flags;
+};
+
+struct perf_record_itrace_start {
+	struct perf_event_header header;
+	__u32			 pid;
+	__u32			 tid;
+};
+
+struct perf_record_aux_output_hw_id {
+	struct perf_event_header header;
+	__u64			hw_id;
+};
+
+struct perf_record_thread_map_entry {
+	__u64			 pid;
+	char			 comm[16];
+};
+
+struct perf_record_thread_map {
+	struct perf_event_header		 header;
+	__u64					 nr;
+	struct perf_record_thread_map_entry	 entries[];
+};
+
+enum {
+	PERF_STAT_CONFIG_TERM__AGGR_MODE	= 0,
+	PERF_STAT_CONFIG_TERM__INTERVAL		= 1,
+	PERF_STAT_CONFIG_TERM__SCALE		= 2,
+	PERF_STAT_CONFIG_TERM__AGGR_LEVEL	= 3,
+	PERF_STAT_CONFIG_TERM__MAX		= 4,
+};
+
+struct perf_record_stat_config_entry {
+	__u64			 tag;
+	__u64			 val;
+};
+
+struct perf_record_stat_config {
+	struct perf_event_header		 header;
+	__u64					 nr;
+	struct perf_record_stat_config_entry	 data[];
+};
+
+struct perf_record_stat {
+	struct perf_event_header header;
+
+	__u64			 id;
+	__u32			 cpu;
+	__u32			 thread;
+
+	union {
+		struct {
+			__u64	 val;
+			__u64	 ena;
+			__u64	 run;
+		};
+		__u64		 values[3];
+	};
+};
+
+struct perf_record_stat_round {
+	struct perf_event_header header;
+	__u64			 type;
+	__u64			 time;
+};
+
+struct perf_record_time_conv {
+	struct perf_event_header header;
+	__u64			 time_shift;
+	__u64			 time_mult;
+	__u64			 time_zero;
+	__u64			 time_cycles;
+	__u64			 time_mask;
+	__u8			 cap_user_time_zero;
+	__u8			 cap_user_time_short;
+	__u8			 reserved[6];	/* For alignment */
+};
+
+struct perf_record_header_feature {
+	struct perf_event_header header;
+	__u64			 feat_id;
+	char			 data[];
+};
+
+struct perf_record_compressed {
+	struct perf_event_header header;
+	char			 data[];
+};
+
+/*
+ * `header.size` includes the padding we are going to add while writing the record.
+ * `data_size` only includes the size of `data[]` itself.
+ */
+struct perf_record_compressed2 {
+	struct perf_event_header header;
+	__u64			 data_size;
+	char			 data[];
+};
+
+#define BPF_METADATA_KEY_LEN   64
+#define BPF_METADATA_VALUE_LEN 256
+#define BPF_PROG_NAME_LEN      KSYM_NAME_LEN
+
+struct perf_record_bpf_metadata_entry {
+	char key[BPF_METADATA_KEY_LEN];
+	char value[BPF_METADATA_VALUE_LEN];
+};
+
+struct perf_record_bpf_metadata {
+	struct perf_event_header	      header;
+	char				      prog_name[BPF_PROG_NAME_LEN];
+	__u64				      nr_entries;
+	struct perf_record_bpf_metadata_entry entries[];
+};
+
+struct perf_record_schedstat_cpu_v15 {
+#define CPU_FIELD(_type, _name, _desc, _format, _is_pct, _pct_of, _ver)		_type _name
+#include "schedstat-v15.h"
+#undef CPU_FIELD
+};
+
+struct perf_record_schedstat_cpu_v16 {
+#define CPU_FIELD(_type, _name, _desc, _format, _is_pct, _pct_of, _ver)		_type _name
+#include "schedstat-v16.h"
+#undef CPU_FIELD
+};
+
+struct perf_record_schedstat_cpu_v17 {
+#define CPU_FIELD(_type, _name, _desc, _format, _is_pct, _pct_of, _ver)		_type _name
+#include "schedstat-v17.h"
+#undef CPU_FIELD
+};
+
+struct perf_record_schedstat_cpu {
+	struct perf_event_header header;
+	__u64			 timestamp;
+	__u32			 cpu;
+	__u16			 version;
+	/* Padding */
+	char			 __pad[2];
+	union {
+		struct perf_record_schedstat_cpu_v15 v15;
+		struct perf_record_schedstat_cpu_v16 v16;
+		struct perf_record_schedstat_cpu_v17 v17;
+	};
+};
+
+struct perf_record_schedstat_domain_v15 {
+#define DOMAIN_FIELD(_type, _name, _desc, _format, _is_jiffies, _ver)		_type _name
+#include "schedstat-v15.h"
+#undef DOMAIN_FIELD
+};
+
+struct perf_record_schedstat_domain_v16 {
+#define DOMAIN_FIELD(_type, _name, _desc, _format, _is_jiffies, _ver)		_type _name
+#include "schedstat-v16.h"
+#undef DOMAIN_FIELD
+};
+
+struct perf_record_schedstat_domain_v17 {
+#define DOMAIN_FIELD(_type, _name, _desc, _format, _is_jiffies, _ver)		_type _name
+#include "schedstat-v17.h"
+#undef DOMAIN_FIELD
+};
+
+#define DOMAIN_NAME_LEN		16
+
+struct perf_record_schedstat_domain {
+	struct perf_event_header header;
+	__u64			 timestamp;
+	__u32			 cpu;
+	__u16			 version;
+	__u16			 domain;
+	union {
+		struct perf_record_schedstat_domain_v15 v15;
+		struct perf_record_schedstat_domain_v16 v16;
+		struct perf_record_schedstat_domain_v17 v17;
+	};
+};
+
+enum perf_user_event_type { /* above any possible kernel type */
+	PERF_RECORD_USER_TYPE_START		= 64,
+	PERF_RECORD_HEADER_ATTR			= 64,
+	PERF_RECORD_HEADER_EVENT_TYPE		= 65, /* deprecated */
+	PERF_RECORD_HEADER_TRACING_DATA		= 66,
+	PERF_RECORD_HEADER_BUILD_ID		= 67,
+	PERF_RECORD_FINISHED_ROUND		= 68,
+	PERF_RECORD_ID_INDEX			= 69,
+	PERF_RECORD_AUXTRACE_INFO		= 70,
+	PERF_RECORD_AUXTRACE			= 71,
+	PERF_RECORD_AUXTRACE_ERROR		= 72,
+	PERF_RECORD_THREAD_MAP			= 73,
+	PERF_RECORD_CPU_MAP			= 74,
+	PERF_RECORD_STAT_CONFIG			= 75,
+	PERF_RECORD_STAT			= 76,
+	PERF_RECORD_STAT_ROUND			= 77,
+	PERF_RECORD_EVENT_UPDATE		= 78,
+	PERF_RECORD_TIME_CONV			= 79,
+	PERF_RECORD_HEADER_FEATURE		= 80,
+	PERF_RECORD_COMPRESSED			= 81,
+	PERF_RECORD_FINISHED_INIT		= 82,
+	PERF_RECORD_COMPRESSED2			= 83,
+	PERF_RECORD_BPF_METADATA		= 84,
+	PERF_RECORD_SCHEDSTAT_CPU		= 85,
+	PERF_RECORD_SCHEDSTAT_DOMAIN		= 86,
+	PERF_RECORD_HEADER_MAX
+};
+
+union perf_event {
+	struct perf_event_header		header;
+	struct perf_record_mmap			mmap;
+	struct perf_record_mmap2		mmap2;
+	struct perf_record_comm			comm;
+	struct perf_record_namespaces		namespaces;
+	struct perf_record_cgroup		cgroup;
+	struct perf_record_fork			fork;
+	struct perf_record_lost			lost;
+	struct perf_record_lost_samples		lost_samples;
+	struct perf_record_read			read;
+	struct perf_record_throttle		throttle;
+	struct perf_record_sample		sample;
+	struct perf_record_callchain_deferred	callchain_deferred;
+	struct perf_record_bpf_event		bpf;
+	struct perf_record_ksymbol		ksymbol;
+	struct perf_record_text_poke_event	text_poke;
+	struct perf_record_header_attr		attr;
+	struct perf_record_event_update		event_update;
+	struct perf_record_header_event_type	event_type;
+	struct perf_record_header_tracing_data	tracing_data;
+	struct perf_record_header_build_id	build_id;
+	struct perf_record_id_index		id_index;
+	struct perf_record_auxtrace_info	auxtrace_info;
+	struct perf_record_auxtrace		auxtrace;
+	struct perf_record_auxtrace_error	auxtrace_error;
+	struct perf_record_aux			aux;
+	struct perf_record_itrace_start		itrace_start;
+	struct perf_record_aux_output_hw_id	aux_output_hw_id;
+	struct perf_record_switch		context_switch;
+	struct perf_record_thread_map		thread_map;
+	struct perf_record_cpu_map		cpu_map;
+	struct perf_record_stat_config		stat_config;
+	struct perf_record_stat			stat;
+	struct perf_record_stat_round		stat_round;
+	struct perf_record_time_conv		time_conv;
+	struct perf_record_header_feature	feat;
+	struct perf_record_compressed		pack;
+	struct perf_record_compressed2		pack2;
+	struct perf_record_bpf_metadata		bpf_metadata;
+	struct perf_record_schedstat_cpu	schedstat_cpu;
+	struct perf_record_schedstat_domain	schedstat_domain;
+};
+
+#endif /* __LIBPERF_EVENT_H */
diff --git a/tools/lib/perf/include/perf/evlist.h b/tools/lib/perf/include/perf/evlist.h
new file mode 100644
index 000000000..e894b7707
--- /dev/null
+++ b/tools/lib/perf/include/perf/evlist.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_EVLIST_H
+#define __LIBPERF_EVLIST_H
+
+#include <perf/core.h>
+#include <stdbool.h>
+
+struct perf_evlist;
+struct perf_evsel;
+struct perf_cpu_map;
+struct perf_thread_map;
+
+LIBPERF_API void perf_evlist__add(struct perf_evlist *evlist,
+				  struct perf_evsel *evsel);
+LIBPERF_API void perf_evlist__remove(struct perf_evlist *evlist,
+				     struct perf_evsel *evsel);
+LIBPERF_API struct perf_evlist *perf_evlist__new(void);
+LIBPERF_API void perf_evlist__delete(struct perf_evlist *evlist);
+LIBPERF_API struct perf_evsel* perf_evlist__next(struct perf_evlist *evlist,
+						 struct perf_evsel *evsel);
+LIBPERF_API int perf_evlist__open(struct perf_evlist *evlist);
+LIBPERF_API void perf_evlist__close(struct perf_evlist *evlist);
+LIBPERF_API void perf_evlist__enable(struct perf_evlist *evlist);
+LIBPERF_API void perf_evlist__disable(struct perf_evlist *evlist);
+
+#define perf_evlist__for_each_evsel(evlist, pos)	\
+	for ((pos) = perf_evlist__next((evlist), NULL);	\
+	     (pos) != NULL;				\
+	     (pos) = perf_evlist__next((evlist), (pos)))
+
+LIBPERF_API void perf_evlist__set_maps(struct perf_evlist *evlist,
+				       struct perf_cpu_map *cpus,
+				       struct perf_thread_map *threads);
+LIBPERF_API int perf_evlist__poll(struct perf_evlist *evlist, int timeout);
+LIBPERF_API int perf_evlist__filter_pollfd(struct perf_evlist *evlist,
+					   short revents_and_mask);
+
+LIBPERF_API int perf_evlist__mmap(struct perf_evlist *evlist, int pages);
+LIBPERF_API void perf_evlist__munmap(struct perf_evlist *evlist);
+
+LIBPERF_API struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
+						     struct perf_mmap *map,
+						     bool overwrite);
+#define perf_evlist__for_each_mmap(evlist, pos, overwrite)		\
+	for ((pos) = perf_evlist__next_mmap((evlist), NULL, overwrite);	\
+	     (pos) != NULL;						\
+	     (pos) = perf_evlist__next_mmap((evlist), (pos), overwrite))
+
+LIBPERF_API void perf_evlist__set_leader(struct perf_evlist *evlist);
+LIBPERF_API int perf_evlist__nr_groups(struct perf_evlist *evlist);
+#endif /* __LIBPERF_EVLIST_H */
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
new file mode 100644
index 000000000..6f9220407
--- /dev/null
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_EVSEL_H
+#define __LIBPERF_EVSEL_H
+
+#include <stdint.h>
+#include <perf/core.h>
+#include <stdbool.h>
+#include <linux/types.h>
+
+struct perf_evsel;
+struct perf_event_attr;
+struct perf_cpu_map;
+struct perf_thread_map;
+
+struct perf_counts_values {
+	union {
+		struct {
+			uint64_t val;
+			uint64_t ena;
+			uint64_t run;
+			uint64_t id;
+			uint64_t lost;
+		};
+		uint64_t values[5];
+	};
+};
+
+LIBPERF_API struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr);
+LIBPERF_API void perf_evsel__delete(struct perf_evsel *evsel);
+LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
+				 struct perf_thread_map *threads);
+LIBPERF_API void perf_evsel__close(struct perf_evsel *evsel);
+LIBPERF_API void perf_evsel__close_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+LIBPERF_API int perf_evsel__mmap(struct perf_evsel *evsel, int pages);
+LIBPERF_API void perf_evsel__munmap(struct perf_evsel *evsel);
+LIBPERF_API void *perf_evsel__mmap_base(struct perf_evsel *evsel, int cpu_map_idx, int thread);
+LIBPERF_API int perf_evsel__read(struct perf_evsel *evsel, int cpu_map_idx, int thread,
+				 struct perf_counts_values *count);
+LIBPERF_API int perf_evsel__enable(struct perf_evsel *evsel);
+LIBPERF_API int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+LIBPERF_API int perf_evsel__enable_thread(struct perf_evsel *evsel, int thread);
+LIBPERF_API int perf_evsel__disable(struct perf_evsel *evsel);
+LIBPERF_API int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+LIBPERF_API struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
+LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
+LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
+LIBPERF_API void perf_counts_values__scale(struct perf_counts_values *count,
+					   bool scale, __s8 *pscaled);
+
+#endif /* __LIBPERF_EVSEL_H */
diff --git a/tools/lib/perf/include/perf/mmap.h b/tools/lib/perf/include/perf/mmap.h
new file mode 100644
index 000000000..9508ad90d
--- /dev/null
+++ b/tools/lib/perf/include/perf/mmap.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_MMAP_H
+#define __LIBPERF_MMAP_H
+
+#include <perf/core.h>
+
+struct perf_mmap;
+union perf_event;
+
+LIBPERF_API void perf_mmap__consume(struct perf_mmap *map);
+LIBPERF_API int perf_mmap__read_init(struct perf_mmap *map);
+LIBPERF_API void perf_mmap__read_done(struct perf_mmap *map);
+LIBPERF_API union perf_event *perf_mmap__read_event(struct perf_mmap *map);
+
+#endif /* __LIBPERF_MMAP_H */
diff --git a/tools/lib/perf/include/perf/schedstat-v15.h b/tools/lib/perf/include/perf/schedstat-v15.h
new file mode 100644
index 000000000..639458df0
--- /dev/null
+++ b/tools/lib/perf/include/perf/schedstat-v15.h
@@ -0,0 +1,146 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifdef CPU_FIELD
+CPU_FIELD(__u32, yld_count, "sched_yield() count",
+	  "%11u", false, yld_count, v15);
+CPU_FIELD(__u32, array_exp, "Legacy counter can be ignored",
+	  "%11u", false, array_exp, v15);
+CPU_FIELD(__u32, sched_count, "schedule() called",
+	  "%11u", false, sched_count, v15);
+CPU_FIELD(__u32, sched_goidle, "schedule() left the processor idle",
+	  "%11u", true, sched_count, v15);
+CPU_FIELD(__u32, ttwu_count, "try_to_wake_up() was called",
+	  "%11u", false, ttwu_count, v15);
+CPU_FIELD(__u32, ttwu_local, "try_to_wake_up() was called to wake up the local cpu",
+	  "%11u", true, ttwu_count, v15);
+CPU_FIELD(__u64, rq_cpu_time, "total runtime by tasks on this processor (in jiffies)",
+	  "%11llu", false, rq_cpu_time, v15);
+CPU_FIELD(__u64, run_delay, "total waittime by tasks on this processor (in jiffies)",
+	  "%11llu", true, rq_cpu_time, v15);
+CPU_FIELD(__u64, pcount, "total timeslices run on this cpu",
+	  "%11llu", false, pcount, v15);
+#endif
+
+#ifdef DOMAIN_FIELD
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category idle> ");
+#endif
+DOMAIN_FIELD(__u32, idle_lb_count,
+	     "load_balance() count on cpu idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, idle_lb_balanced,
+	     "load_balance() found balanced on cpu idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, idle_lb_failed,
+	     "load_balance() move task failed on cpu idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, idle_lb_imbalance,
+	     "imbalance sum on cpu idle", "%11u", false, v15);
+DOMAIN_FIELD(__u32, idle_lb_gained,
+	     "pull_task() count on cpu idle", "%11u", false, v15);
+DOMAIN_FIELD(__u32, idle_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu idle", "%11u", false, v15);
+DOMAIN_FIELD(__u32, idle_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, idle_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu idle", "%11u", true, v15);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(idle_lb_success_count, "load_balance() success count on cpu idle", "%11u",
+		  idle_lb_count, idle_lb_balanced, idle_lb_failed, v15);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(idle_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu idle)", "%11.2Lf",
+		  idle_lb_count, idle_lb_balanced, idle_lb_failed, idle_lb_gained, v15);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category busy> ");
+#endif
+DOMAIN_FIELD(__u32, busy_lb_count,
+	     "load_balance() count on cpu busy", "%11u", true, v15);
+DOMAIN_FIELD(__u32, busy_lb_balanced,
+	     "load_balance() found balanced on cpu busy", "%11u", true, v15);
+DOMAIN_FIELD(__u32, busy_lb_failed,
+	     "load_balance() move task failed on cpu busy", "%11u", true, v15);
+DOMAIN_FIELD(__u32, busy_lb_imbalance,
+	     "imbalance sum on cpu busy", "%11u", false, v15);
+DOMAIN_FIELD(__u32, busy_lb_gained,
+	     "pull_task() count on cpu busy", "%11u", false, v15);
+DOMAIN_FIELD(__u32, busy_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu busy", "%11u", false, v15);
+DOMAIN_FIELD(__u32, busy_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu busy", "%11u", true, v15);
+DOMAIN_FIELD(__u32, busy_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu busy", "%11u", true, v15);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(busy_lb_success_count, "load_balance() success count on cpu busy", "%11u",
+		  busy_lb_count, busy_lb_balanced, busy_lb_failed, v15);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(busy_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu busy)", "%11.2Lf",
+		  busy_lb_count, busy_lb_balanced, busy_lb_failed, busy_lb_gained, v15);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category newidle> ");
+#endif
+DOMAIN_FIELD(__u32, newidle_lb_count,
+	     "load_balance() count on cpu newly idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, newidle_lb_balanced,
+	     "load_balance() found balanced on cpu newly idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, newidle_lb_failed,
+	     "load_balance() move task failed on cpu newly idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, newidle_lb_imbalance,
+	     "imbalance sum on cpu newly idle", "%11u", false, v15);
+DOMAIN_FIELD(__u32, newidle_lb_gained,
+	     "pull_task() count on cpu newly idle", "%11u", false, v15);
+DOMAIN_FIELD(__u32, newidle_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu newly idle", "%11u", false, v15);
+DOMAIN_FIELD(__u32, newidle_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu newly idle", "%11u", true, v15);
+DOMAIN_FIELD(__u32, newidle_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu newly idle", "%11u", true, v15);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(newidle_lb_success_count,
+		  "load_balance() success count on cpu newly idle", "%11u",
+		  newidle_lb_count, newidle_lb_balanced, newidle_lb_failed, v15);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(newidle_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu newly idle)", "%11.2Lf",
+		  newidle_lb_count, newidle_lb_balanced, newidle_lb_failed, newidle_lb_gained, v15);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category active_load_balance()> ");
+#endif
+DOMAIN_FIELD(__u32, alb_count,
+	     "active_load_balance() count", "%11u", false, v15);
+DOMAIN_FIELD(__u32, alb_failed,
+	     "active_load_balance() move task failed", "%11u", false, v15);
+DOMAIN_FIELD(__u32, alb_pushed,
+	     "active_load_balance() successfully moved a task", "%11u", false, v15);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category sched_balance_exec()> ");
+#endif
+DOMAIN_FIELD(__u32, sbe_count,
+	     "sbe_count is not used", "%11u", false, v15);
+DOMAIN_FIELD(__u32, sbe_balanced,
+	     "sbe_balanced is not used", "%11u", false, v15);
+DOMAIN_FIELD(__u32, sbe_pushed,
+	     "sbe_pushed is not used", "%11u", false, v15);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category sched_balance_fork()> ");
+#endif
+DOMAIN_FIELD(__u32, sbf_count,
+	     "sbf_count is not used", "%11u", false, v15);
+DOMAIN_FIELD(__u32, sbf_balanced,
+	     "sbf_balanced is not used", "%11u", false, v15);
+DOMAIN_FIELD(__u32, sbf_pushed,
+	     "sbf_pushed is not used", "%11u", false, v15);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Wakeup Info> ");
+#endif
+DOMAIN_FIELD(__u32, ttwu_wake_remote,
+	     "try_to_wake_up() awoke a task that last ran on a diff cpu", "%11u", false, v15);
+DOMAIN_FIELD(__u32, ttwu_move_affine,
+	     "try_to_wake_up() moved task because cache-cold on own cpu", "%11u", false, v15);
+DOMAIN_FIELD(__u32, ttwu_move_balance,
+	     "try_to_wake_up() started passive balancing", "%11u", false, v15);
+#endif /* DOMAIN_FIELD */
diff --git a/tools/lib/perf/include/perf/schedstat-v16.h b/tools/lib/perf/include/perf/schedstat-v16.h
new file mode 100644
index 000000000..3462b79c2
--- /dev/null
+++ b/tools/lib/perf/include/perf/schedstat-v16.h
@@ -0,0 +1,146 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifdef CPU_FIELD
+CPU_FIELD(__u32, yld_count, "sched_yield() count",
+	  "%11u", false, yld_count, v16);
+CPU_FIELD(__u32, array_exp, "Legacy counter can be ignored",
+	  "%11u", false, array_exp, v16);
+CPU_FIELD(__u32, sched_count, "schedule() called",
+	  "%11u", false, sched_count, v16);
+CPU_FIELD(__u32, sched_goidle, "schedule() left the processor idle",
+	  "%11u", true, sched_count, v16);
+CPU_FIELD(__u32, ttwu_count, "try_to_wake_up() was called",
+	  "%11u", false, ttwu_count, v16);
+CPU_FIELD(__u32, ttwu_local, "try_to_wake_up() was called to wake up the local cpu",
+	  "%11u", true, ttwu_count, v16);
+CPU_FIELD(__u64, rq_cpu_time, "total runtime by tasks on this processor (in jiffies)",
+	  "%11llu", false, rq_cpu_time, v16);
+CPU_FIELD(__u64, run_delay, "total waittime by tasks on this processor (in jiffies)",
+	  "%11llu", true, rq_cpu_time, v16);
+CPU_FIELD(__u64, pcount, "total timeslices run on this cpu",
+	  "%11llu", false, pcount, v16);
+#endif /* CPU_FIELD */
+
+#ifdef DOMAIN_FIELD
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category busy> ");
+#endif
+DOMAIN_FIELD(__u32, busy_lb_count,
+	     "load_balance() count on cpu busy", "%11u", true, v16);
+DOMAIN_FIELD(__u32, busy_lb_balanced,
+	     "load_balance() found balanced on cpu busy", "%11u", true, v16);
+DOMAIN_FIELD(__u32, busy_lb_failed,
+	     "load_balance() move task failed on cpu busy", "%11u", true, v16);
+DOMAIN_FIELD(__u32, busy_lb_imbalance,
+	     "imbalance sum on cpu busy", "%11u", false, v16);
+DOMAIN_FIELD(__u32, busy_lb_gained,
+	     "pull_task() count on cpu busy", "%11u", false, v16);
+DOMAIN_FIELD(__u32, busy_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu busy", "%11u", false, v16);
+DOMAIN_FIELD(__u32, busy_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu busy", "%11u", true, v16);
+DOMAIN_FIELD(__u32, busy_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu busy", "%11u", true, v16);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(busy_lb_success_count, "load_balance() success count on cpu busy", "%11u",
+		  busy_lb_count, busy_lb_balanced, busy_lb_failed, v16);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(busy_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu busy)", "%11.2Lf",
+		  busy_lb_count, busy_lb_balanced, busy_lb_failed, busy_lb_gained, v16);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category idle> ");
+#endif
+DOMAIN_FIELD(__u32, idle_lb_count,
+	     "load_balance() count on cpu idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, idle_lb_balanced,
+	     "load_balance() found balanced on cpu idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, idle_lb_failed,
+	     "load_balance() move task failed on cpu idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, idle_lb_imbalance,
+	     "imbalance sum on cpu idle", "%11u", false, v16);
+DOMAIN_FIELD(__u32, idle_lb_gained,
+	     "pull_task() count on cpu idle", "%11u", false, v16);
+DOMAIN_FIELD(__u32, idle_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu idle", "%11u", false, v16);
+DOMAIN_FIELD(__u32, idle_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, idle_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu idle", "%11u", true, v16);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(idle_lb_success_count, "load_balance() success count on cpu idle", "%11u",
+		  idle_lb_count, idle_lb_balanced, idle_lb_failed, v16);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(idle_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu idle)", "%11.2Lf",
+		  idle_lb_count, idle_lb_balanced, idle_lb_failed, idle_lb_gained, v16);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category newidle> ");
+#endif
+DOMAIN_FIELD(__u32, newidle_lb_count,
+	     "load_balance() count on cpu newly idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, newidle_lb_balanced,
+	     "load_balance() found balanced on cpu newly idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, newidle_lb_failed,
+	     "load_balance() move task failed on cpu newly idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, newidle_lb_imbalance,
+	     "imbalance sum on cpu newly idle", "%11u", false, v16);
+DOMAIN_FIELD(__u32, newidle_lb_gained,
+	     "pull_task() count on cpu newly idle", "%11u", false, v16);
+DOMAIN_FIELD(__u32, newidle_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu newly idle", "%11u", false, v16);
+DOMAIN_FIELD(__u32, newidle_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu newly idle", "%11u", true, v16);
+DOMAIN_FIELD(__u32, newidle_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu newly idle", "%11u", true, v16);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(newidle_lb_success_count,
+		  "load_balance() success count on cpu newly idle", "%11u",
+		  newidle_lb_count, newidle_lb_balanced, newidle_lb_failed, v16);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(newidle_lb_avg_count,
+		  "avg task pulled per successful lb attempt (cpu newly idle)", "%11.2Lf",
+		  newidle_lb_count, newidle_lb_balanced, newidle_lb_failed, newidle_lb_gained, v16);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category active_load_balance()> ");
+#endif
+DOMAIN_FIELD(__u32, alb_count,
+	     "active_load_balance() count", "%11u", false, v16);
+DOMAIN_FIELD(__u32, alb_failed,
+	     "active_load_balance() move task failed", "%11u", false, v16);
+DOMAIN_FIELD(__u32, alb_pushed,
+	     "active_load_balance() successfully moved a task", "%11u", false, v16);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category sched_balance_exec()> ");
+#endif
+DOMAIN_FIELD(__u32, sbe_count,
+	     "sbe_count is not used", "%11u", false, v16);
+DOMAIN_FIELD(__u32, sbe_balanced,
+	     "sbe_balanced is not used", "%11u", false, v16);
+DOMAIN_FIELD(__u32, sbe_pushed,
+	     "sbe_pushed is not used", "%11u", false, v16);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category sched_balance_fork()> ");
+#endif
+DOMAIN_FIELD(__u32, sbf_count,
+	     "sbf_count is not used", "%11u", false, v16);
+DOMAIN_FIELD(__u32, sbf_balanced,
+	     "sbf_balanced is not used", "%11u", false, v16);
+DOMAIN_FIELD(__u32, sbf_pushed,
+	     "sbf_pushed is not used", "%11u", false, v16);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Wakeup Info> ");
+#endif
+DOMAIN_FIELD(__u32, ttwu_wake_remote,
+	     "try_to_wake_up() awoke a task that last ran on a diff cpu", "%11u", false, v16);
+DOMAIN_FIELD(__u32, ttwu_move_affine,
+	     "try_to_wake_up() moved task because cache-cold on own cpu", "%11u", false, v16);
+DOMAIN_FIELD(__u32, ttwu_move_balance,
+	     "try_to_wake_up() started passive balancing", "%11u", false, v16);
+#endif /* DOMAIN_FIELD */
diff --git a/tools/lib/perf/include/perf/schedstat-v17.h b/tools/lib/perf/include/perf/schedstat-v17.h
new file mode 100644
index 000000000..865dc7c10
--- /dev/null
+++ b/tools/lib/perf/include/perf/schedstat-v17.h
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifdef CPU_FIELD
+CPU_FIELD(__u32, yld_count, "sched_yield() count",
+	  "%11u", false, yld_count, v17);
+CPU_FIELD(__u32, array_exp, "Legacy counter can be ignored",
+	  "%11u", false, array_exp, v17);
+CPU_FIELD(__u32, sched_count, "schedule() called",
+	  "%11u", false, sched_count, v17);
+CPU_FIELD(__u32, sched_goidle, "schedule() left the processor idle",
+	  "%11u", true, sched_count, v17);
+CPU_FIELD(__u32, ttwu_count, "try_to_wake_up() was called",
+	  "%11u", false, ttwu_count, v17);
+CPU_FIELD(__u32, ttwu_local, "try_to_wake_up() was called to wake up the local cpu",
+	  "%11u", true, ttwu_count, v17);
+CPU_FIELD(__u64, rq_cpu_time, "total runtime by tasks on this processor (in jiffies)",
+	  "%11llu", false, rq_cpu_time, v17);
+CPU_FIELD(__u64, run_delay, "total waittime by tasks on this processor (in jiffies)",
+	  "%11llu", true, rq_cpu_time, v17);
+CPU_FIELD(__u64, pcount, "total timeslices run on this cpu",
+	  "%11llu", false, pcount, v17);
+#endif /* CPU_FIELD */
+
+#ifdef DOMAIN_FIELD
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category busy> ");
+#endif
+DOMAIN_FIELD(__u32, busy_lb_count,
+	     "load_balance() count on cpu busy", "%11u", true, v17);
+DOMAIN_FIELD(__u32, busy_lb_balanced,
+	     "load_balance() found balanced on cpu busy", "%11u", true, v17);
+DOMAIN_FIELD(__u32, busy_lb_failed,
+	     "load_balance() move task failed on cpu busy", "%11u", true, v17);
+DOMAIN_FIELD(__u32, busy_lb_imbalance_load,
+	     "imbalance in load on cpu busy", "%11u", false, v17);
+DOMAIN_FIELD(__u32, busy_lb_imbalance_util,
+	     "imbalance in utilization on cpu busy", "%11u", false, v17);
+DOMAIN_FIELD(__u32, busy_lb_imbalance_task,
+	     "imbalance in number of tasks on cpu busy", "%11u", false, v17);
+DOMAIN_FIELD(__u32, busy_lb_imbalance_misfit,
+	     "imbalance in misfit tasks on cpu busy", "%11u", false, v17);
+DOMAIN_FIELD(__u32, busy_lb_gained,
+	     "pull_task() count on cpu busy", "%11u", false, v17);
+DOMAIN_FIELD(__u32, busy_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu busy", "%11u", false, v17);
+DOMAIN_FIELD(__u32, busy_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu busy", "%11u", true, v17);
+DOMAIN_FIELD(__u32, busy_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu busy", "%11u", true, v17);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(busy_lb_success_count, "load_balance() success count on cpu busy", "%11u",
+		  busy_lb_count, busy_lb_balanced, busy_lb_failed, v17);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(busy_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu busy)", "%11.2Lf",
+		  busy_lb_count, busy_lb_balanced, busy_lb_failed, busy_lb_gained, v17);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category idle> ");
+#endif
+DOMAIN_FIELD(__u32, idle_lb_count,
+	     "load_balance() count on cpu idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, idle_lb_balanced,
+	     "load_balance() found balanced on cpu idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, idle_lb_failed,
+	     "load_balance() move task failed on cpu idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, idle_lb_imbalance_load,
+	     "imbalance in load on cpu idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, idle_lb_imbalance_util,
+	     "imbalance in utilization on cpu idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, idle_lb_imbalance_task,
+	     "imbalance in number of tasks on cpu idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, idle_lb_imbalance_misfit,
+	     "imbalance in misfit tasks on cpu idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, idle_lb_gained,
+	     "pull_task() count on cpu idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, idle_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, idle_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, idle_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu idle", "%11u", true, v17);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(idle_lb_success_count, "load_balance() success count on cpu idle", "%11u",
+		  idle_lb_count, idle_lb_balanced, idle_lb_failed, v17);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(idle_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu idle)", "%11.2Lf",
+		  idle_lb_count, idle_lb_balanced, idle_lb_failed, idle_lb_gained, v17);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category newidle> ");
+#endif
+DOMAIN_FIELD(__u32, newidle_lb_count,
+	     "load_balance() count on cpu newly idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, newidle_lb_balanced,
+	     "load_balance() found balanced on cpu newly idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, newidle_lb_failed,
+	     "load_balance() move task failed on cpu newly idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, newidle_lb_imbalance_load,
+	     "imbalance in load on cpu newly idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, newidle_lb_imbalance_util,
+	     "imbalance in utilization on cpu newly idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, newidle_lb_imbalance_task,
+	     "imbalance in number of tasks on cpu newly idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, newidle_lb_imbalance_misfit,
+	     "imbalance in misfit tasks on cpu newly idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, newidle_lb_gained,
+	     "pull_task() count on cpu newly idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, newidle_lb_hot_gained,
+	     "pull_task() when target task was cache-hot on cpu newly idle", "%11u", false, v17);
+DOMAIN_FIELD(__u32, newidle_lb_nobusyq,
+	     "load_balance() failed to find busier queue on cpu newly idle", "%11u", true, v17);
+DOMAIN_FIELD(__u32, newidle_lb_nobusyg,
+	     "load_balance() failed to find busier group on cpu newly idle", "%11u", true, v17);
+#ifdef DERIVED_CNT_FIELD
+DERIVED_CNT_FIELD(newidle_lb_success_count,
+		  "load_balance() success count on cpu newly idle", "%11u",
+		  newidle_lb_count, newidle_lb_balanced, newidle_lb_failed, v17);
+#endif
+#ifdef DERIVED_AVG_FIELD
+DERIVED_AVG_FIELD(newidle_lb_avg_pulled,
+		  "avg task pulled per successful lb attempt (cpu newly idle)", "%11.2Lf",
+		  newidle_lb_count, newidle_lb_balanced, newidle_lb_failed, newidle_lb_gained, v17);
+#endif
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category active_load_balance()> ");
+#endif
+DOMAIN_FIELD(__u32, alb_count,
+	     "active_load_balance() count", "%11u", false, v17);
+DOMAIN_FIELD(__u32, alb_failed,
+	     "active_load_balance() move task failed", "%11u", false, v17);
+DOMAIN_FIELD(__u32, alb_pushed,
+	     "active_load_balance() successfully moved a task", "%11u", false, v17);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category sched_balance_exec()> ");
+#endif
+DOMAIN_FIELD(__u32, sbe_count,
+	     "sbe_count is not used", "%11u", false, v17);
+DOMAIN_FIELD(__u32, sbe_balanced,
+	     "sbe_balanced is not used", "%11u", false, v17);
+DOMAIN_FIELD(__u32, sbe_pushed,
+	     "sbe_pushed is not used", "%11u", false, v17);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Category sched_balance_fork()> ");
+#endif
+DOMAIN_FIELD(__u32, sbf_count,
+	     "sbf_count is not used", "%11u", false, v17);
+DOMAIN_FIELD(__u32, sbf_balanced,
+	     "sbf_balanced is not used", "%11u", false, v17);
+DOMAIN_FIELD(__u32, sbf_pushed,
+	     "sbf_pushed is not used", "%11u", false, v17);
+#ifdef DOMAIN_CATEGORY
+DOMAIN_CATEGORY(" <Wakeup Info> ");
+#endif
+DOMAIN_FIELD(__u32, ttwu_wake_remote,
+	     "try_to_wake_up() awoke a task that last ran on a diff cpu", "%11u", false, v17);
+DOMAIN_FIELD(__u32, ttwu_move_affine,
+	     "try_to_wake_up() moved task because cache-cold on own cpu", "%11u", false, v17);
+DOMAIN_FIELD(__u32, ttwu_move_balance,
+	     "try_to_wake_up() started passive balancing", "%11u", false, v17);
+#endif /* DOMAIN_FIELD */
diff --git a/tools/lib/perf/include/perf/threadmap.h b/tools/lib/perf/include/perf/threadmap.h
new file mode 100644
index 000000000..44deb815b
--- /dev/null
+++ b/tools/lib/perf/include/perf/threadmap.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_THREADMAP_H
+#define __LIBPERF_THREADMAP_H
+
+#include <perf/core.h>
+#include <sys/types.h>
+
+struct perf_thread_map;
+
+LIBPERF_API struct perf_thread_map *perf_thread_map__new_dummy(void);
+LIBPERF_API struct perf_thread_map *perf_thread_map__new_array(int nr_threads, pid_t *array);
+
+LIBPERF_API void perf_thread_map__set_pid(struct perf_thread_map *map, int idx, pid_t pid);
+LIBPERF_API char *perf_thread_map__comm(struct perf_thread_map *map, int idx);
+LIBPERF_API int perf_thread_map__nr(struct perf_thread_map *threads);
+LIBPERF_API pid_t perf_thread_map__pid(struct perf_thread_map *map, int idx);
+LIBPERF_API int perf_thread_map__idx(struct perf_thread_map *map, pid_t pid);
+
+LIBPERF_API struct perf_thread_map *perf_thread_map__get(struct perf_thread_map *map);
+LIBPERF_API void perf_thread_map__put(struct perf_thread_map *map);
+
+#endif /* __LIBPERF_THREADMAP_H */
diff --git a/tools/lib/perf/internal.h b/tools/lib/perf/internal.h
new file mode 100644
index 000000000..2c27e158d
--- /dev/null
+++ b/tools/lib/perf/internal.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_H
+#define __LIBPERF_INTERNAL_H
+
+#include <perf/core.h>
+
+void libperf_print(enum libperf_print_level level,
+		   const char *format, ...)
+	__attribute__((format(printf, 2, 3)));
+
+#define __pr(level, fmt, ...)   \
+do {                            \
+	libperf_print(level, "libperf: " fmt, ##__VA_ARGS__);     \
+} while (0)
+
+#define pr_err(fmt, ...)        __pr(LIBPERF_ERR, fmt, ##__VA_ARGS__)
+#define pr_warning(fmt, ...)    __pr(LIBPERF_WARN, fmt, ##__VA_ARGS__)
+#define pr_info(fmt, ...)       __pr(LIBPERF_INFO, fmt, ##__VA_ARGS__)
+#define pr_debug(fmt, ...)      __pr(LIBPERF_DEBUG, fmt, ##__VA_ARGS__)
+#define pr_debug2(fmt, ...)     __pr(LIBPERF_DEBUG2, fmt, ##__VA_ARGS__)
+#define pr_debug3(fmt, ...)     __pr(LIBPERF_DEBUG3, fmt, ##__VA_ARGS__)
+
+#endif /* __LIBPERF_INTERNAL_H */
diff --git a/tools/lib/perf/lib.c b/tools/lib/perf/lib.c
new file mode 100644
index 000000000..696fb0ea6
--- /dev/null
+++ b/tools/lib/perf/lib.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <unistd.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <linux/kernel.h>
+#include <internal/lib.h>
+
+unsigned int page_size;
+
+static ssize_t ion(bool is_read, int fd, void *buf, size_t n)
+{
+	void *buf_start = buf;
+	size_t left = n;
+
+	while (left) {
+		/* buf must be treated as const if !is_read. */
+		ssize_t ret = is_read ? read(fd, buf, left) :
+					write(fd, buf, left);
+
+		if (ret < 0 && errno == EINTR)
+			continue;
+		if (ret <= 0)
+			return ret;
+
+		left -= ret;
+		buf  += ret;
+	}
+
+	BUG_ON((size_t)(buf - buf_start) != n);
+	return n;
+}
+
+/*
+ * Read exactly 'n' bytes or return an error.
+ */
+ssize_t readn(int fd, void *buf, size_t n)
+{
+	return ion(true, fd, buf, n);
+}
+
+ssize_t preadn(int fd, void *buf, size_t n, off_t offs)
+{
+	size_t left = n;
+
+	while (left) {
+		ssize_t ret = pread(fd, buf, left, offs);
+
+		if (ret < 0 && errno == EINTR)
+			continue;
+		if (ret <= 0)
+			return ret;
+
+		left -= ret;
+		buf  += ret;
+		offs += ret;
+	}
+
+	return n;
+}
+
+/*
+ * Write exactly 'n' bytes or return an error.
+ */
+ssize_t writen(int fd, const void *buf, size_t n)
+{
+	/* ion does not modify buf. */
+	return ion(false, fd, (void *)buf, n);
+}
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
new file mode 100644
index 000000000..fdd8304fe
--- /dev/null
+++ b/tools/lib/perf/libperf.map
@@ -0,0 +1,62 @@
+LIBPERF_0.0.1 {
+	global:
+		libperf_init;
+		perf_cpu_map__new_any_cpu;
+		perf_cpu_map__new_online_cpus;
+		perf_cpu_map__get;
+		perf_cpu_map__put;
+		perf_cpu_map__new;
+		perf_cpu_map__nr;
+		perf_cpu_map__cpu;
+		perf_cpu_map__has_any_cpu_or_is_empty;
+		perf_cpu_map__is_any_cpu_or_is_empty;
+		perf_cpu_map__is_empty;
+		perf_cpu_map__has_any_cpu;
+		perf_cpu_map__min;
+		perf_cpu_map__max;
+		perf_cpu_map__has;
+		perf_thread_map__new_array;
+		perf_thread_map__new_dummy;
+		perf_thread_map__set_pid;
+		perf_thread_map__comm;
+		perf_thread_map__nr;
+		perf_thread_map__pid;
+		perf_thread_map__get;
+		perf_thread_map__put;
+		perf_evsel__new;
+		perf_evsel__delete;
+		perf_evsel__enable;
+		perf_evsel__disable;
+		perf_evsel__open;
+		perf_evsel__close;
+		perf_evsel__mmap;
+		perf_evsel__munmap;
+		perf_evsel__mmap_base;
+		perf_evsel__read;
+		perf_evsel__cpus;
+		perf_evsel__threads;
+		perf_evsel__attr;
+		perf_evlist__new;
+		perf_evlist__delete;
+		perf_evlist__open;
+		perf_evlist__close;
+		perf_evlist__enable;
+		perf_evlist__disable;
+		perf_evlist__add;
+		perf_evlist__remove;
+		perf_evlist__next;
+		perf_evlist__set_maps;
+		perf_evlist__poll;
+		perf_evlist__mmap;
+		perf_evlist__munmap;
+		perf_evlist__filter_pollfd;
+		perf_evlist__next_mmap;
+		perf_evlist__set_leader;
+		perf_mmap__consume;
+		perf_mmap__read_init;
+		perf_mmap__read_done;
+		perf_mmap__read_event;
+		perf_counts_values__scale;
+	local:
+		*;
+};
diff --git a/tools/lib/perf/libperf.pc.template b/tools/lib/perf/libperf.pc.template
new file mode 100644
index 000000000..117e4a237
--- /dev/null
+++ b/tools/lib/perf/libperf.pc.template
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+prefix=@PREFIX@
+libdir=@LIBDIR@
+includedir=${prefix}/include
+
+Name: libperf
+Description: perf library
+Version: @VERSION@
+Libs: -L${libdir} -lperf
+Cflags: -I${includedir}
diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
new file mode 100644
index 000000000..ec124eb0e
--- /dev/null
+++ b/tools/lib/perf/mmap.c
@@ -0,0 +1,539 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <sys/mman.h>
+#include <inttypes.h>
+#include <asm/bug.h>
+#include <errno.h>
+#include <string.h>
+#include <linux/ring_buffer.h>
+#include <linux/perf_event.h>
+#include <perf/mmap.h>
+#include <perf/event.h>
+#include <perf/evsel.h>
+#include <internal/mmap.h>
+#include <internal/lib.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/stringify.h>
+#include "internal.h"
+
+void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
+		     bool overwrite, libperf_unmap_cb_t unmap_cb)
+{
+	/* Assume fields were zero initialized. */
+	map->fd = -1;
+	map->overwrite = overwrite;
+	map->unmap_cb  = unmap_cb;
+	refcount_set(&map->refcnt, 0);
+	if (prev)
+		prev->next = map;
+}
+
+size_t perf_mmap__mmap_len(struct perf_mmap *map)
+{
+	return map->mask + 1 + page_size;
+}
+
+int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
+		    int fd, struct perf_cpu cpu)
+{
+	map->prev = 0;
+	map->mask = mp->mask;
+	map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
+			 MAP_SHARED, fd, 0);
+	if (map->base == MAP_FAILED) {
+		map->base = NULL;
+		return -1;
+	}
+
+	map->fd  = fd;
+	map->cpu = cpu;
+	return 0;
+}
+
+void perf_mmap__munmap(struct perf_mmap *map)
+{
+	if (!map)
+		return;
+
+	zfree(&map->event_copy);
+	map->event_copy_sz = 0;
+	if (map->base) {
+		munmap(map->base, perf_mmap__mmap_len(map));
+		map->base = NULL;
+		map->fd = -1;
+		refcount_set(&map->refcnt, 0);
+	}
+	if (map->unmap_cb)
+		map->unmap_cb(map);
+}
+
+void perf_mmap__get(struct perf_mmap *map)
+{
+	refcount_inc(&map->refcnt);
+}
+
+void perf_mmap__put(struct perf_mmap *map)
+{
+	BUG_ON(map->base && refcount_read(&map->refcnt) == 0);
+
+	if (refcount_dec_and_test(&map->refcnt))
+		perf_mmap__munmap(map);
+}
+
+static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
+{
+	ring_buffer_write_tail(md->base, tail);
+}
+
+u64 perf_mmap__read_head(struct perf_mmap *map)
+{
+	return ring_buffer_read_head(map->base);
+}
+
+static bool perf_mmap__empty(struct perf_mmap *map)
+{
+	struct perf_event_mmap_page *pc = map->base;
+
+	return perf_mmap__read_head(map) == map->prev && !pc->aux_size;
+}
+
+void perf_mmap__consume(struct perf_mmap *map)
+{
+	if (!map->overwrite) {
+		u64 old = map->prev;
+
+		perf_mmap__write_tail(map, old);
+	}
+
+	if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))
+		perf_mmap__put(map);
+}
+
+static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
+{
+	struct perf_event_header *pheader;
+	u64 evt_head = *start;
+	int size = mask + 1;
+
+	pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
+	pheader = (struct perf_event_header *)(buf + (*start & mask));
+	while (true) {
+		if (evt_head - *start >= (unsigned int)size) {
+			pr_debug("Finished reading overwrite ring buffer: rewind\n");
+			if (evt_head - *start > (unsigned int)size)
+				evt_head -= pheader->size;
+			*end = evt_head;
+			return 0;
+		}
+
+		pheader = (struct perf_event_header *)(buf + (evt_head & mask));
+
+		if (pheader->size == 0) {
+			pr_debug("Finished reading overwrite ring buffer: get start\n");
+			*end = evt_head;
+			return 0;
+		}
+
+		evt_head += pheader->size;
+		pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
+	}
+	WARN_ONCE(1, "Shouldn't get here\n");
+	return -1;
+}
+
+/*
+ * Report the start and end of the available data in ringbuffer
+ */
+static int __perf_mmap__read_init(struct perf_mmap *md)
+{
+	u64 head = perf_mmap__read_head(md);
+	u64 old = md->prev;
+	unsigned char *data = md->base + page_size;
+	unsigned long size;
+
+	md->start = md->overwrite ? head : old;
+	md->end = md->overwrite ? old : head;
+
+	if ((md->end - md->start) < md->flush)
+		return -EAGAIN;
+
+	size = md->end - md->start;
+	if (size > (unsigned long)(md->mask) + 1) {
+		if (!md->overwrite) {
+			WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
+
+			md->prev = head;
+			perf_mmap__consume(md);
+			return -EAGAIN;
+		}
+
+		/*
+		 * Backward ring buffer is full. We still have a chance to read
+		 * most of data from it.
+		 */
+		if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+int perf_mmap__read_init(struct perf_mmap *map)
+{
+	/*
+	 * Check if event was unmapped due to a POLLHUP/POLLERR.
+	 */
+	if (!refcount_read(&map->refcnt))
+		return -ENOENT;
+
+	return __perf_mmap__read_init(map);
+}
+
+/*
+ * Mandatory for overwrite mode
+ * The direction of overwrite mode is backward.
+ * The last perf_mmap__read() will set tail to map->core.prev.
+ * Need to correct the map->core.prev to head which is the end of next read.
+ */
+void perf_mmap__read_done(struct perf_mmap *map)
+{
+	/*
+	 * Check if event was unmapped due to a POLLHUP/POLLERR.
+	 */
+	if (!refcount_read(&map->refcnt))
+		return;
+
+	map->prev = perf_mmap__read_head(map);
+}
+
+/* When check_messup is true, 'end' must points to a good entry */
+static union perf_event *perf_mmap__read(struct perf_mmap *map,
+					 u64 *startp, u64 end)
+{
+	unsigned char *data = map->base + page_size;
+	union perf_event *event = NULL;
+	int diff = end - *startp;
+
+	if (diff >= (int)sizeof(event->header)) {
+		size_t size;
+
+		event = (union perf_event *)&data[*startp & map->mask];
+		size = event->header.size;
+
+		if (size < sizeof(event->header) || diff < (int)size)
+			return NULL;
+
+		/*
+		 * Event straddles the mmap boundary -- header should always
+		 * be inside due to u64 alignment of output.
+		 */
+		if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {
+			unsigned int offset = *startp;
+			unsigned int len = size, cpy;
+			void *dst = map->event_copy;
+
+			if (size > map->event_copy_sz) {
+				dst = realloc(map->event_copy, size);
+				if (!dst)
+					return NULL;
+				map->event_copy = dst;
+				map->event_copy_sz = size;
+			}
+
+			do {
+				cpy = min(map->mask + 1 - (offset & map->mask), len);
+				memcpy(dst, &data[offset & map->mask], cpy);
+				offset += cpy;
+				dst += cpy;
+				len -= cpy;
+			} while (len);
+
+			event = (union perf_event *)map->event_copy;
+		}
+
+		*startp += size;
+	}
+
+	return event;
+}
+
+/*
+ * Read event from ring buffer one by one.
+ * Return one event for each call.
+ *
+ * Usage:
+ * perf_mmap__read_init()
+ * while(event = perf_mmap__read_event()) {
+ *	//process the event
+ *	perf_mmap__consume()
+ * }
+ * perf_mmap__read_done()
+ */
+union perf_event *perf_mmap__read_event(struct perf_mmap *map)
+{
+	union perf_event *event;
+
+	/*
+	 * Check if event was unmapped due to a POLLHUP/POLLERR.
+	 */
+	if (!refcount_read(&map->refcnt))
+		return NULL;
+
+	/* non-overwrite doesn't pause the ringbuffer */
+	if (!map->overwrite)
+		map->end = perf_mmap__read_head(map);
+
+	event = perf_mmap__read(map, &map->start, map->end);
+
+	if (!map->overwrite)
+		map->prev = map->start;
+
+	return event;
+}
+
+#if defined(__i386__) || defined(__x86_64__)
+static u64 read_perf_counter(unsigned int counter)
+{
+	unsigned int low, high;
+
+	asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
+
+	return low | ((u64)high) << 32;
+}
+
+static u64 read_timestamp(void)
+{
+	unsigned int low, high;
+
+	asm volatile("rdtsc" : "=a" (low), "=d" (high));
+
+	return low | ((u64)high) << 32;
+}
+#elif defined(__aarch64__)
+#define read_sysreg(r) ({						\
+	u64 __val;							\
+	asm volatile("mrs %0, " __stringify(r) : "=r" (__val));		\
+	__val;								\
+})
+
+static u64 read_pmccntr(void)
+{
+	return read_sysreg(pmccntr_el0);
+}
+
+#define PMEVCNTR_READ(idx)					\
+	static u64 read_pmevcntr_##idx(void) {			\
+		return read_sysreg(pmevcntr##idx##_el0);	\
+	}
+
+PMEVCNTR_READ(0);
+PMEVCNTR_READ(1);
+PMEVCNTR_READ(2);
+PMEVCNTR_READ(3);
+PMEVCNTR_READ(4);
+PMEVCNTR_READ(5);
+PMEVCNTR_READ(6);
+PMEVCNTR_READ(7);
+PMEVCNTR_READ(8);
+PMEVCNTR_READ(9);
+PMEVCNTR_READ(10);
+PMEVCNTR_READ(11);
+PMEVCNTR_READ(12);
+PMEVCNTR_READ(13);
+PMEVCNTR_READ(14);
+PMEVCNTR_READ(15);
+PMEVCNTR_READ(16);
+PMEVCNTR_READ(17);
+PMEVCNTR_READ(18);
+PMEVCNTR_READ(19);
+PMEVCNTR_READ(20);
+PMEVCNTR_READ(21);
+PMEVCNTR_READ(22);
+PMEVCNTR_READ(23);
+PMEVCNTR_READ(24);
+PMEVCNTR_READ(25);
+PMEVCNTR_READ(26);
+PMEVCNTR_READ(27);
+PMEVCNTR_READ(28);
+PMEVCNTR_READ(29);
+PMEVCNTR_READ(30);
+
+/*
+ * Read a value direct from PMEVCNTR<idx>
+ */
+static u64 read_perf_counter(unsigned int counter)
+{
+	static u64 (* const read_f[])(void) = {
+		read_pmevcntr_0,
+		read_pmevcntr_1,
+		read_pmevcntr_2,
+		read_pmevcntr_3,
+		read_pmevcntr_4,
+		read_pmevcntr_5,
+		read_pmevcntr_6,
+		read_pmevcntr_7,
+		read_pmevcntr_8,
+		read_pmevcntr_9,
+		read_pmevcntr_10,
+		read_pmevcntr_11,
+		read_pmevcntr_13,
+		read_pmevcntr_12,
+		read_pmevcntr_14,
+		read_pmevcntr_15,
+		read_pmevcntr_16,
+		read_pmevcntr_17,
+		read_pmevcntr_18,
+		read_pmevcntr_19,
+		read_pmevcntr_20,
+		read_pmevcntr_21,
+		read_pmevcntr_22,
+		read_pmevcntr_23,
+		read_pmevcntr_24,
+		read_pmevcntr_25,
+		read_pmevcntr_26,
+		read_pmevcntr_27,
+		read_pmevcntr_28,
+		read_pmevcntr_29,
+		read_pmevcntr_30,
+		read_pmccntr
+	};
+
+	if (counter < ARRAY_SIZE(read_f))
+		return (read_f[counter])();
+
+	return 0;
+}
+
+static u64 read_timestamp(void) { return read_sysreg(cntvct_el0); }
+
+/* __riscv_xlen contains the witdh of the native base integer, here 64-bit */
+#elif defined(__riscv) && __riscv_xlen == 64
+
+/* TODO: implement rv32 support */
+
+#define CSR_CYCLE	0xc00
+#define CSR_TIME	0xc01
+
+#define csr_read(csr)						\
+({								\
+	register unsigned long __v;				\
+		__asm__ __volatile__ ("csrr %0, %1"		\
+		 : "=r" (__v)					\
+		 : "i" (csr) : );				\
+		 __v;						\
+})
+
+static unsigned long csr_read_num(int csr_num)
+{
+#define switchcase_csr_read(__csr_num, __val)           {\
+	case __csr_num:                                 \
+		__val = csr_read(__csr_num);            \
+		break; }
+#define switchcase_csr_read_2(__csr_num, __val)         {\
+	switchcase_csr_read(__csr_num + 0, __val)        \
+	switchcase_csr_read(__csr_num + 1, __val)}
+#define switchcase_csr_read_4(__csr_num, __val)         {\
+	switchcase_csr_read_2(__csr_num + 0, __val)      \
+	switchcase_csr_read_2(__csr_num + 2, __val)}
+#define switchcase_csr_read_8(__csr_num, __val)         {\
+	switchcase_csr_read_4(__csr_num + 0, __val)      \
+	switchcase_csr_read_4(__csr_num + 4, __val)}
+#define switchcase_csr_read_16(__csr_num, __val)        {\
+	switchcase_csr_read_8(__csr_num + 0, __val)      \
+	switchcase_csr_read_8(__csr_num + 8, __val)}
+#define switchcase_csr_read_32(__csr_num, __val)        {\
+	switchcase_csr_read_16(__csr_num + 0, __val)     \
+	switchcase_csr_read_16(__csr_num + 16, __val)}
+
+	unsigned long ret = 0;
+
+	switch (csr_num) {
+	switchcase_csr_read_32(CSR_CYCLE, ret)
+	default:
+		break;
+	}
+
+	return ret;
+#undef switchcase_csr_read_32
+#undef switchcase_csr_read_16
+#undef switchcase_csr_read_8
+#undef switchcase_csr_read_4
+#undef switchcase_csr_read_2
+#undef switchcase_csr_read
+}
+
+static u64 read_perf_counter(unsigned int counter)
+{
+	return csr_read_num(CSR_CYCLE + counter);
+}
+
+static u64 read_timestamp(void)
+{
+	return csr_read_num(CSR_TIME);
+}
+
+#else
+static u64 read_perf_counter(unsigned int counter __maybe_unused) { return 0; }
+static u64 read_timestamp(void) { return 0; }
+#endif
+
+int perf_mmap__read_self(struct perf_mmap *map, struct perf_counts_values *count)
+{
+	struct perf_event_mmap_page *pc = map->base;
+	u32 seq, idx, time_mult = 0, time_shift = 0;
+	u64 cnt, cyc = 0, time_offset = 0, time_cycles = 0, time_mask = ~0ULL;
+
+	if (!pc || !pc->cap_user_rdpmc)
+		return -1;
+
+	do {
+		seq = READ_ONCE(pc->lock);
+		barrier();
+
+		count->ena = READ_ONCE(pc->time_enabled);
+		count->run = READ_ONCE(pc->time_running);
+
+		if (pc->cap_user_time && count->ena != count->run) {
+			cyc = read_timestamp();
+			time_mult = READ_ONCE(pc->time_mult);
+			time_shift = READ_ONCE(pc->time_shift);
+			time_offset = READ_ONCE(pc->time_offset);
+
+			if (pc->cap_user_time_short) {
+				time_cycles = READ_ONCE(pc->time_cycles);
+				time_mask = READ_ONCE(pc->time_mask);
+			}
+		}
+
+		idx = READ_ONCE(pc->index);
+		cnt = READ_ONCE(pc->offset);
+		if (pc->cap_user_rdpmc && idx) {
+			u64 evcnt = read_perf_counter(idx - 1);
+			u16 width = READ_ONCE(pc->pmc_width);
+
+			evcnt <<= 64 - width;
+			evcnt >>= 64 - width;
+			cnt += evcnt;
+		} else
+			return -1;
+
+		barrier();
+	} while (READ_ONCE(pc->lock) != seq);
+
+	if (count->ena != count->run) {
+		u64 delta;
+
+		/* Adjust for cap_usr_time_short, a nop if not */
+		cyc = time_cycles + ((cyc - time_cycles) & time_mask);
+
+		delta = time_offset + mul_u64_u32_shr(cyc, time_mult, time_shift);
+
+		count->ena += delta;
+		if (idx)
+			count->run += delta;
+	}
+
+	count->val = cnt;
+
+	return 0;
+}
diff --git a/tools/lib/perf/tests/Build b/tools/lib/perf/tests/Build
new file mode 100644
index 000000000..56e81378d
--- /dev/null
+++ b/tools/lib/perf/tests/Build
@@ -0,0 +1,5 @@
+tests-y += main.o
+tests-y += test-evsel.o
+tests-y += test-evlist.o
+tests-y += test-cpumap.o
+tests-y += test-threadmap.o
diff --git a/tools/lib/perf/tests/main.c b/tools/lib/perf/tests/main.c
new file mode 100644
index 000000000..56423fd4d
--- /dev/null
+++ b/tools/lib/perf/tests/main.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <internal/tests.h>
+#include "tests.h"
+
+int tests_failed;
+int tests_verbose;
+
+int main(int argc, char **argv)
+{
+	__T("test cpumap", !test_cpumap(argc, argv));
+	__T("test threadmap", !test_threadmap(argc, argv));
+	__T("test evlist", !test_evlist(argc, argv));
+	__T("test evsel", !test_evsel(argc, argv));
+	return 0;
+}
diff --git a/tools/lib/perf/tests/test-cpumap.c b/tools/lib/perf/tests/test-cpumap.c
new file mode 100644
index 000000000..c998b1dae
--- /dev/null
+++ b/tools/lib/perf/tests/test-cpumap.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdarg.h>
+#include <stdio.h>
+#include <perf/cpumap.h>
+#include <internal/tests.h>
+#include "tests.h"
+
+static int libperf_print(enum libperf_print_level level,
+			 const char *fmt, va_list ap)
+{
+	return vfprintf(stderr, fmt, ap);
+}
+
+int test_cpumap(int argc, char **argv)
+{
+	struct perf_cpu_map *cpus;
+	struct perf_cpu cpu;
+	int idx;
+
+	__T_START;
+
+	libperf_init(libperf_print);
+
+	cpus = perf_cpu_map__new_any_cpu();
+	if (!cpus)
+		return -1;
+
+	perf_cpu_map__get(cpus);
+	perf_cpu_map__put(cpus);
+	perf_cpu_map__put(cpus);
+
+	cpus = perf_cpu_map__new_online_cpus();
+	if (!cpus)
+		return -1;
+
+	perf_cpu_map__for_each_cpu(cpu, idx, cpus)
+		__T("wrong cpu number", cpu.cpu != -1);
+
+	perf_cpu_map__put(cpus);
+
+	__T_END;
+	return tests_failed == 0 ? 0 : -1;
+}
diff --git a/tools/lib/perf/tests/test-evlist.c b/tools/lib/perf/tests/test-evlist.c
new file mode 100644
index 000000000..10f70cb41
--- /dev/null
+++ b/tools/lib/perf/tests/test-evlist.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE // needed for sched.h to get sched_[gs]etaffinity and CPU_(ZERO,SET)
+#include <inttypes.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <linux/perf_event.h>
+#include <linux/limits.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/prctl.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <perf/evlist.h>
+#include <perf/evsel.h>
+#include <perf/mmap.h>
+#include <perf/event.h>
+#include <internal/tests.h>
+#include <api/fs/fs.h>
+#include "tests.h"
+#include <internal/evsel.h>
+
+#define EVENT_NUM 15
+#define WAIT_COUNT 100000000UL
+
+static int libperf_print(enum libperf_print_level level,
+			 const char *fmt, va_list ap)
+{
+	return vfprintf(stderr, fmt, ap);
+}
+
+static int test_stat_cpu(void)
+{
+	struct perf_cpu_map *cpus;
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel, *leader;
+	struct perf_event_attr attr1 = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_CPU_CLOCK,
+	};
+	struct perf_event_attr attr2 = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_TASK_CLOCK,
+	};
+	int err, idx;
+
+	cpus = perf_cpu_map__new_online_cpus();
+	__T("failed to create cpus", cpus);
+
+	evlist = perf_evlist__new();
+	__T("failed to create evlist", evlist);
+
+	evsel = leader = perf_evsel__new(&attr1);
+	__T("failed to create evsel1", evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	evsel = perf_evsel__new(&attr2);
+	__T("failed to create evsel2", evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	perf_evlist__set_leader(evlist);
+	__T("failed to set leader", leader->leader == leader);
+	__T("failed to set leader", evsel->leader  == leader);
+
+	perf_evlist__set_maps(evlist, cpus, NULL);
+
+	err = perf_evlist__open(evlist);
+	__T("failed to open evlist", err == 0);
+
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		cpus = perf_evsel__cpus(evsel);
+
+		for (idx = 0; idx < perf_cpu_map__nr(cpus); idx++) {
+			struct perf_counts_values counts = { .val = 0 };
+
+			perf_evsel__read(evsel, idx, 0, &counts);
+			__T("failed to read value for evsel", counts.val != 0);
+		}
+	}
+
+	perf_evlist__close(evlist);
+	perf_evlist__delete(evlist);
+
+	perf_cpu_map__put(cpus);
+	return 0;
+}
+
+static int test_stat_thread(void)
+{
+	struct perf_counts_values counts = { .val = 0 };
+	struct perf_thread_map *threads;
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel, *leader;
+	struct perf_event_attr attr1 = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_CPU_CLOCK,
+	};
+	struct perf_event_attr attr2 = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_TASK_CLOCK,
+	};
+	int err;
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evlist = perf_evlist__new();
+	__T("failed to create evlist", evlist);
+
+	evsel = leader = perf_evsel__new(&attr1);
+	__T("failed to create evsel1", evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	evsel = perf_evsel__new(&attr2);
+	__T("failed to create evsel2", evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	perf_evlist__set_leader(evlist);
+	__T("failed to set leader", leader->leader == leader);
+	__T("failed to set leader", evsel->leader  == leader);
+
+	perf_evlist__set_maps(evlist, NULL, threads);
+
+	err = perf_evlist__open(evlist);
+	__T("failed to open evlist", err == 0);
+
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		perf_evsel__read(evsel, 0, 0, &counts);
+		__T("failed to read value for evsel", counts.val != 0);
+	}
+
+	perf_evlist__close(evlist);
+	perf_evlist__delete(evlist);
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+static int test_stat_thread_enable(void)
+{
+	struct perf_counts_values counts = { .val = 0 };
+	struct perf_thread_map *threads;
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel, *leader;
+	struct perf_event_attr attr1 = {
+		.type	  = PERF_TYPE_SOFTWARE,
+		.config	  = PERF_COUNT_SW_CPU_CLOCK,
+		.disabled = 1,
+	};
+	struct perf_event_attr attr2 = {
+		.type	  = PERF_TYPE_SOFTWARE,
+		.config	  = PERF_COUNT_SW_TASK_CLOCK,
+		.disabled = 1,
+	};
+	int err;
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evlist = perf_evlist__new();
+	__T("failed to create evlist", evlist);
+
+	evsel = leader = perf_evsel__new(&attr1);
+	__T("failed to create evsel1", evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	evsel = perf_evsel__new(&attr2);
+	__T("failed to create evsel2", evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	perf_evlist__set_leader(evlist);
+	__T("failed to set leader", leader->leader == leader);
+	__T("failed to set leader", evsel->leader  == leader);
+
+	perf_evlist__set_maps(evlist, NULL, threads);
+
+	err = perf_evlist__open(evlist);
+	__T("failed to open evlist", err == 0);
+
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		perf_evsel__read(evsel, 0, 0, &counts);
+		__T("failed to read value for evsel", counts.val == 0);
+	}
+
+	perf_evlist__enable(evlist);
+
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		perf_evsel__read(evsel, 0, 0, &counts);
+		__T("failed to read value for evsel", counts.val != 0);
+	}
+
+	perf_evlist__disable(evlist);
+
+	perf_evlist__close(evlist);
+	perf_evlist__delete(evlist);
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+static int test_mmap_thread(void)
+{
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	struct perf_mmap *map;
+	struct perf_cpu_map *cpus;
+	struct perf_thread_map *threads;
+	struct perf_event_attr attr = {
+		.type             = PERF_TYPE_TRACEPOINT,
+		.sample_period    = 1,
+		.wakeup_watermark = 1,
+		.disabled         = 1,
+	};
+	char path[PATH_MAX];
+	int id, err, pid, go_pipe[2];
+	union perf_event *event;
+	int count = 0;
+
+	snprintf(path, PATH_MAX, "%s/kernel/debug/tracing/events/syscalls/sys_enter_prctl/id",
+		 sysfs__mountpoint());
+
+	if (filename__read_int(path, &id)) {
+		tests_failed++;
+		fprintf(stderr, "error: failed to get tracepoint id: %s\n", path);
+		return -1;
+	}
+
+	attr.config = id;
+
+	err = pipe(go_pipe);
+	__T("failed to create pipe", err == 0);
+
+	fflush(NULL);
+
+	pid = fork();
+	if (!pid) {
+		int i;
+		char bf;
+
+		read(go_pipe[0], &bf, 1);
+
+		/* Generate 100 prctl calls. */
+		for (i = 0; i < 100; i++)
+			prctl(0, 0, 0, 0, 0);
+
+		exit(0);
+	}
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	cpus = perf_cpu_map__new_any_cpu();
+	__T("failed to create cpus", cpus);
+
+	perf_thread_map__set_pid(threads, 0, pid);
+
+	evlist = perf_evlist__new();
+	__T("failed to create evlist", evlist);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel1", evsel);
+	__T("failed to set leader", evsel->leader == evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	perf_evlist__set_maps(evlist, cpus, threads);
+
+	err = perf_evlist__open(evlist);
+	__T("failed to open evlist", err == 0);
+
+	err = perf_evlist__mmap(evlist, 4);
+	__T("failed to mmap evlist", err == 0);
+
+	perf_evlist__enable(evlist);
+
+	/* kick the child and wait for it to finish */
+	write(go_pipe[1], "A", 1);
+	waitpid(pid, NULL, 0);
+
+	/*
+	 * There's no need to call perf_evlist__disable,
+	 * monitored process is dead now.
+	 */
+
+	perf_evlist__for_each_mmap(evlist, map, false) {
+		if (perf_mmap__read_init(map) < 0)
+			continue;
+
+		while ((event = perf_mmap__read_event(map)) != NULL) {
+			count++;
+			perf_mmap__consume(map);
+		}
+
+		perf_mmap__read_done(map);
+	}
+
+	/* calls perf_evlist__munmap/perf_evlist__close */
+	perf_evlist__delete(evlist);
+
+	perf_thread_map__put(threads);
+	perf_cpu_map__put(cpus);
+
+	/*
+	 * The generated prctl calls should match the
+	 * number of events in the buffer.
+	 */
+	__T("failed count", count == 100);
+
+	return 0;
+}
+
+static int test_mmap_cpus(void)
+{
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	struct perf_mmap *map;
+	struct perf_cpu_map *cpus;
+	struct perf_event_attr attr = {
+		.type             = PERF_TYPE_TRACEPOINT,
+		.sample_period    = 1,
+		.wakeup_watermark = 1,
+		.disabled         = 1,
+	};
+	cpu_set_t saved_mask;
+	char path[PATH_MAX];
+	int id, err, tmp;
+	struct perf_cpu cpu;
+	union perf_event *event;
+	int count = 0;
+
+	snprintf(path, PATH_MAX, "%s/kernel/debug/tracing/events/syscalls/sys_enter_prctl/id",
+		 sysfs__mountpoint());
+
+	if (filename__read_int(path, &id)) {
+		fprintf(stderr, "error: failed to get tracepoint id: %s\n", path);
+		return -1;
+	}
+
+	attr.config = id;
+
+	cpus = perf_cpu_map__new_online_cpus();
+	__T("failed to create cpus", cpus);
+
+	evlist = perf_evlist__new();
+	__T("failed to create evlist", evlist);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel1", evsel);
+	__T("failed to set leader", evsel->leader == evsel);
+
+	perf_evlist__add(evlist, evsel);
+
+	perf_evlist__set_maps(evlist, cpus, NULL);
+
+	err = perf_evlist__open(evlist);
+	__T("failed to open evlist", err == 0);
+
+	err = perf_evlist__mmap(evlist, 4);
+	__T("failed to mmap evlist", err == 0);
+
+	perf_evlist__enable(evlist);
+
+	err = sched_getaffinity(0, sizeof(saved_mask), &saved_mask);
+	__T("sched_getaffinity failed", err == 0);
+
+	perf_cpu_map__for_each_cpu(cpu, tmp, cpus) {
+		cpu_set_t mask;
+
+		CPU_ZERO(&mask);
+		CPU_SET(cpu.cpu, &mask);
+
+		err = sched_setaffinity(0, sizeof(mask), &mask);
+		__T("sched_setaffinity failed", err == 0);
+
+		prctl(0, 0, 0, 0, 0);
+	}
+
+	err = sched_setaffinity(0, sizeof(saved_mask), &saved_mask);
+	__T("sched_setaffinity failed", err == 0);
+
+	perf_evlist__disable(evlist);
+
+	perf_evlist__for_each_mmap(evlist, map, false) {
+		if (perf_mmap__read_init(map) < 0)
+			continue;
+
+		while ((event = perf_mmap__read_event(map)) != NULL) {
+			count++;
+			perf_mmap__consume(map);
+		}
+
+		perf_mmap__read_done(map);
+	}
+
+	/* calls perf_evlist__munmap/perf_evlist__close */
+	perf_evlist__delete(evlist);
+
+	/*
+	 * The generated prctl events should match the
+	 * number of cpus or be bigger (we are system-wide).
+	 */
+	__T("failed count", count >= perf_cpu_map__nr(cpus));
+
+	perf_cpu_map__put(cpus);
+
+	return 0;
+}
+
+static double display_error(long long average,
+			    long long high,
+			    long long low,
+			    long long expected)
+{
+	double error;
+
+	error = (((double)average - expected) / expected) * 100.0;
+
+	__T_VERBOSE("   Expected: %lld\n", expected);
+	__T_VERBOSE("   High: %lld   Low:  %lld   Average:  %lld\n",
+		    high, low, average);
+
+	__T_VERBOSE("   Average Error = %.2f%%\n", error);
+
+	return error;
+}
+
+static int test_stat_multiplexing(void)
+{
+	struct perf_counts_values expected_counts = { .val = 0 };
+	struct perf_counts_values counts[EVENT_NUM] = {{ .val = 0 },};
+	struct perf_thread_map *threads;
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr = {
+		.type	     = PERF_TYPE_HARDWARE,
+		.config	     = PERF_COUNT_HW_INSTRUCTIONS,
+		.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
+			       PERF_FORMAT_TOTAL_TIME_RUNNING,
+		.disabled    = 1,
+	};
+	int err, i, nonzero = 0;
+	unsigned long count;
+	long long max = 0, min = 0, avg = 0;
+	double error = 0.0;
+	s8 scaled = 0;
+
+	/* read for non-multiplexing event count */
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, NULL, threads);
+	__T("failed to open evsel", err == 0);
+
+	err = perf_evsel__enable(evsel);
+	__T("failed to enable evsel", err == 0);
+
+	/* wait loop */
+	count = WAIT_COUNT;
+	while (count--)
+		;
+
+	perf_evsel__read(evsel, 0, 0, &expected_counts);
+	__T("failed to read value for evsel", expected_counts.val != 0);
+	__T("failed to read non-multiplexing event count",
+	    expected_counts.ena == expected_counts.run);
+
+	err = perf_evsel__disable(evsel);
+	__T("failed to enable evsel", err == 0);
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_thread_map__put(threads);
+
+	/* read for multiplexing event count */
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evlist = perf_evlist__new();
+	__T("failed to create evlist", evlist);
+
+	for (i = 0; i < EVENT_NUM; i++) {
+		evsel = perf_evsel__new(&attr);
+		__T("failed to create evsel", evsel);
+
+		perf_evlist__add(evlist, evsel);
+	}
+	perf_evlist__set_maps(evlist, NULL, threads);
+
+	err = perf_evlist__open(evlist);
+	__T("failed to open evlist", err == 0);
+
+	perf_evlist__enable(evlist);
+
+	/* wait loop */
+	count = WAIT_COUNT;
+	while (count--)
+		;
+
+	i = 0;
+	perf_evlist__for_each_evsel(evlist, evsel) {
+		perf_evsel__read(evsel, 0, 0, &counts[i]);
+		__T("failed to read value for evsel", counts[i].val != 0);
+		i++;
+	}
+
+	perf_evlist__disable(evlist);
+
+	min = counts[0].val;
+	for (i = 0; i < EVENT_NUM; i++) {
+		__T_VERBOSE("Event %2d -- Raw count = %" PRIu64 ", run = %" PRIu64 ", enable = %" PRIu64 "\n",
+			    i, counts[i].val, counts[i].run, counts[i].ena);
+
+		perf_counts_values__scale(&counts[i], true, &scaled);
+		if (scaled == 1) {
+			__T_VERBOSE("\t Scaled count = %" PRIu64 " (%.2lf%%, %" PRIu64 "/%" PRIu64 ")\n",
+				    counts[i].val,
+				    (double)counts[i].run / (double)counts[i].ena * 100.0,
+				    counts[i].run, counts[i].ena);
+		} else if (scaled == -1) {
+			__T_VERBOSE("\t Not Running\n");
+		} else {
+			__T_VERBOSE("\t Not Scaling\n");
+		}
+
+		if (counts[i].val > max)
+			max = counts[i].val;
+
+		if (counts[i].val < min)
+			min = counts[i].val;
+
+		avg += counts[i].val;
+
+		if (counts[i].val != 0)
+			nonzero++;
+	}
+
+	if (nonzero != 0)
+		avg = avg / nonzero;
+	else
+		avg = 0;
+
+	error = display_error(avg, max, min, expected_counts.val);
+
+	__T("Error out of range!", ((error <= 1.0) && (error >= -1.0)));
+
+	perf_evlist__close(evlist);
+	perf_evlist__delete(evlist);
+
+	perf_thread_map__put(threads);
+
+	return 0;
+}
+
+int test_evlist(int argc, char **argv)
+{
+	__T_START;
+
+	libperf_init(libperf_print);
+
+	test_stat_cpu();
+	test_stat_thread();
+	test_stat_thread_enable();
+	test_mmap_thread();
+	test_mmap_cpus();
+	test_stat_multiplexing();
+
+	__T_END;
+	return tests_failed == 0 ? 0 : -1;
+}
diff --git a/tools/lib/perf/tests/test-evsel.c b/tools/lib/perf/tests/test-evsel.c
new file mode 100644
index 000000000..545ec3150
--- /dev/null
+++ b/tools/lib/perf/tests/test-evsel.c
@@ -0,0 +1,367 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <linux/perf_event.h>
+#include <linux/kernel.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <perf/evsel.h>
+#include <internal/evsel.h>
+#include <internal/tests.h>
+#include "tests.h"
+
+static int libperf_print(enum libperf_print_level level,
+			 const char *fmt, va_list ap)
+{
+	return vfprintf(stderr, fmt, ap);
+}
+
+static int test_stat_cpu(void)
+{
+	struct perf_cpu_map *cpus;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_CPU_CLOCK,
+	};
+	int err, idx;
+
+	cpus = perf_cpu_map__new_online_cpus();
+	__T("failed to create cpus", cpus);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, cpus, NULL);
+	__T("failed to open evsel", err == 0);
+
+	for (idx = 0; idx < perf_cpu_map__nr(cpus); idx++) {
+		struct perf_counts_values counts = { .val = 0 };
+
+		perf_evsel__read(evsel, idx, 0, &counts);
+		__T("failed to read value for evsel", counts.val != 0);
+	}
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_cpu_map__put(cpus);
+	return 0;
+}
+
+static int test_stat_thread(void)
+{
+	struct perf_counts_values counts = { .val = 0 };
+	struct perf_thread_map *threads;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_TASK_CLOCK,
+	};
+	int err;
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, NULL, threads);
+	__T("failed to open evsel", err == 0);
+
+	perf_evsel__read(evsel, 0, 0, &counts);
+	__T("failed to read value for evsel", counts.val != 0);
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+static int test_stat_thread_enable(void)
+{
+	struct perf_counts_values counts = { .val = 0 };
+	struct perf_thread_map *threads;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr = {
+		.type	  = PERF_TYPE_SOFTWARE,
+		.config	  = PERF_COUNT_SW_TASK_CLOCK,
+		.disabled = 1,
+	};
+	int err;
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, NULL, threads);
+	__T("failed to open evsel", err == 0);
+
+	perf_evsel__read(evsel, 0, 0, &counts);
+	__T("failed to read value for evsel", counts.val == 0);
+
+	err = perf_evsel__enable(evsel);
+	__T("failed to enable evsel", err == 0);
+
+	perf_evsel__read(evsel, 0, 0, &counts);
+	__T("failed to read value for evsel", counts.val != 0);
+
+	err = perf_evsel__disable(evsel);
+	__T("failed to enable evsel", err == 0);
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+static int test_stat_user_read(int event)
+{
+	struct perf_counts_values counts = { .val = 0 };
+	struct perf_thread_map *threads;
+	struct perf_evsel *evsel;
+	struct perf_event_mmap_page *pc;
+	struct perf_event_attr attr = {
+		.type	= PERF_TYPE_HARDWARE,
+		.config	= event,
+#ifdef __aarch64__
+		.config1 = 0x2,		/* Request user access */
+#endif
+	};
+	int err, i;
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, NULL, threads);
+	__T("failed to open evsel", err == 0);
+
+	err = perf_evsel__mmap(evsel, 0);
+	__T("failed to mmap evsel", err == 0);
+
+	pc = perf_evsel__mmap_base(evsel, 0, 0);
+	__T("failed to get mmapped address", pc);
+
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
+	__T("userspace counter access not supported", pc->cap_user_rdpmc);
+	__T("userspace counter access not enabled", pc->index);
+	__T("userspace counter width not set", pc->pmc_width >= 32);
+#endif
+
+	perf_evsel__read(evsel, 0, 0, &counts);
+	__T("failed to read value for evsel", counts.val != 0);
+
+	for (i = 0; i < 5; i++) {
+		volatile int count = 0x10000 << i;
+		__u64 start, end, last = 0;
+
+		__T_VERBOSE("\tloop = %u, ", count);
+
+		perf_evsel__read(evsel, 0, 0, &counts);
+		start = counts.val;
+
+		while (count--) ;
+
+		perf_evsel__read(evsel, 0, 0, &counts);
+		end = counts.val;
+
+		__T("invalid counter data", (end - start) > last);
+		last = end - start;
+		__T_VERBOSE("count = %llu\n", end - start);
+	}
+
+	perf_evsel__munmap(evsel);
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+static int test_stat_read_format_single(struct perf_event_attr *attr, struct perf_thread_map *threads)
+{
+	struct perf_evsel *evsel;
+	struct perf_counts_values counts;
+	volatile int count = 0x100000;
+	int err;
+
+	evsel = perf_evsel__new(attr);
+	__T("failed to create evsel", evsel);
+
+	/* skip old kernels that don't support the format */
+	err = perf_evsel__open(evsel, NULL, threads);
+	if (err < 0)
+		return 0;
+
+	while (count--) ;
+
+	memset(&counts, -1, sizeof(counts));
+	perf_evsel__read(evsel, 0, 0, &counts);
+
+	__T("failed to read value", counts.val);
+	if (attr->read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		__T("failed to read TOTAL_TIME_ENABLED", counts.ena);
+	if (attr->read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		__T("failed to read TOTAL_TIME_RUNNING", counts.run);
+	if (attr->read_format & PERF_FORMAT_ID)
+		__T("failed to read ID", counts.id);
+	if (attr->read_format & PERF_FORMAT_LOST)
+		__T("failed to read LOST", counts.lost == 0);
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+	return 0;
+}
+
+static int test_stat_read_format_group(struct perf_event_attr *attr, struct perf_thread_map *threads)
+{
+	struct perf_evsel *leader, *member;
+	struct perf_counts_values counts;
+	volatile int count = 0x100000;
+	int err;
+
+	attr->read_format |= PERF_FORMAT_GROUP;
+	leader = perf_evsel__new(attr);
+	__T("failed to create leader", leader);
+
+	attr->read_format &= ~PERF_FORMAT_GROUP;
+	member = perf_evsel__new(attr);
+	__T("failed to create member", member);
+
+	member->leader = leader;
+	leader->nr_members = 2;
+
+	/* skip old kernels that don't support the format */
+	err = perf_evsel__open(leader, NULL, threads);
+	if (err < 0)
+		return 0;
+	err = perf_evsel__open(member, NULL, threads);
+	if (err < 0)
+		return 0;
+
+	while (count--) ;
+
+	memset(&counts, -1, sizeof(counts));
+	perf_evsel__read(leader, 0, 0, &counts);
+
+	__T("failed to read leader value", counts.val);
+	if (attr->read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		__T("failed to read leader TOTAL_TIME_ENABLED", counts.ena);
+	if (attr->read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		__T("failed to read leader TOTAL_TIME_RUNNING", counts.run);
+	if (attr->read_format & PERF_FORMAT_ID)
+		__T("failed to read leader ID", counts.id);
+	if (attr->read_format & PERF_FORMAT_LOST)
+		__T("failed to read leader LOST", counts.lost == 0);
+
+	memset(&counts, -1, sizeof(counts));
+	perf_evsel__read(member, 0, 0, &counts);
+
+	__T("failed to read member value", counts.val);
+	if (attr->read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		__T("failed to read member TOTAL_TIME_ENABLED", counts.ena);
+	if (attr->read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		__T("failed to read member TOTAL_TIME_RUNNING", counts.run);
+	if (attr->read_format & PERF_FORMAT_ID)
+		__T("failed to read member ID", counts.id);
+	if (attr->read_format & PERF_FORMAT_LOST)
+		__T("failed to read member LOST", counts.lost == 0);
+
+	perf_evsel__close(member);
+	perf_evsel__close(leader);
+	perf_evsel__delete(member);
+	perf_evsel__delete(leader);
+	return 0;
+}
+
+static int test_stat_read_format(void)
+{
+	struct perf_thread_map *threads;
+	struct perf_event_attr attr = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_TASK_CLOCK,
+	};
+	int err, i;
+
+#define FMT(_fmt)  PERF_FORMAT_ ## _fmt
+#define FMT_TIME  (FMT(TOTAL_TIME_ENABLED) | FMT(TOTAL_TIME_RUNNING))
+
+	uint64_t test_formats [] = {
+		0,
+		FMT_TIME,
+		FMT(ID),
+		FMT(LOST),
+		FMT_TIME | FMT(ID),
+		FMT_TIME | FMT(LOST),
+		FMT_TIME | FMT(ID) | FMT(LOST),
+		FMT(ID) | FMT(LOST),
+	};
+
+#undef FMT
+#undef FMT_TIME
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	for (i = 0; i < (int)ARRAY_SIZE(test_formats); i++) {
+		attr.read_format = test_formats[i];
+		__T_VERBOSE("testing single read with read_format: %lx\n",
+			    (unsigned long)test_formats[i]);
+
+		err = test_stat_read_format_single(&attr, threads);
+		__T("failed to read single format", err == 0);
+	}
+
+	perf_thread_map__put(threads);
+
+	threads = perf_thread_map__new_array(2, NULL);
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+	perf_thread_map__set_pid(threads, 1, 0);
+
+	for (i = 0; i < (int)ARRAY_SIZE(test_formats); i++) {
+		attr.read_format = test_formats[i];
+		__T_VERBOSE("testing group read with read_format: %lx\n",
+			    (unsigned long)test_formats[i]);
+
+		err = test_stat_read_format_group(&attr, threads);
+		__T("failed to read group format", err == 0);
+	}
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+int test_evsel(int argc, char **argv)
+{
+	__T_START;
+
+	libperf_init(libperf_print);
+
+	test_stat_cpu();
+	test_stat_thread();
+	test_stat_thread_enable();
+	test_stat_user_read(PERF_COUNT_HW_INSTRUCTIONS);
+	test_stat_user_read(PERF_COUNT_HW_CPU_CYCLES);
+	test_stat_read_format();
+
+	__T_END;
+	return tests_failed == 0 ? 0 : -1;
+}
diff --git a/tools/lib/perf/tests/test-threadmap.c b/tools/lib/perf/tests/test-threadmap.c
new file mode 100644
index 000000000..f728ad700
--- /dev/null
+++ b/tools/lib/perf/tests/test-threadmap.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdarg.h>
+#include <stdio.h>
+#include <perf/threadmap.h>
+#include <internal/tests.h>
+#include "tests.h"
+
+static int libperf_print(enum libperf_print_level level,
+			 const char *fmt, va_list ap)
+{
+	return vfprintf(stderr, fmt, ap);
+}
+
+static int test_threadmap_array(int nr, pid_t *array)
+{
+	struct perf_thread_map *threads;
+	int i;
+
+	threads = perf_thread_map__new_array(nr, array);
+	__T("Failed to allocate new thread map", threads);
+
+	__T("Unexpected number of threads", perf_thread_map__nr(threads) == nr);
+
+	for (i = 0; i < nr; i++) {
+		__T("Unexpected initial value of thread",
+		    perf_thread_map__pid(threads, i) == (array ? array[i] : -1));
+	}
+
+	for (i = 1; i < nr; i++)
+		perf_thread_map__set_pid(threads, i, i * 100);
+
+	__T("Unexpected value of thread 0",
+	    perf_thread_map__pid(threads, 0) == (array ? array[0] : -1));
+
+	for (i = 1; i < nr; i++) {
+		__T("Unexpected thread value",
+		    perf_thread_map__pid(threads, i) == i * 100);
+	}
+
+	perf_thread_map__put(threads);
+
+	return 0;
+}
+
+#define THREADS_NR	10
+int test_threadmap(int argc, char **argv)
+{
+	struct perf_thread_map *threads;
+	pid_t thr_array[THREADS_NR];
+	int i;
+
+	__T_START;
+
+	libperf_init(libperf_print);
+
+	threads = perf_thread_map__new_dummy();
+	if (!threads)
+		return -1;
+
+	perf_thread_map__get(threads);
+	perf_thread_map__put(threads);
+	perf_thread_map__put(threads);
+
+	test_threadmap_array(THREADS_NR, NULL);
+
+	for (i = 0; i < THREADS_NR; i++)
+		thr_array[i] = i + 100;
+
+	test_threadmap_array(THREADS_NR, thr_array);
+
+	__T_END;
+	return tests_failed == 0 ? 0 : -1;
+}
diff --git a/tools/lib/perf/tests/tests.h b/tools/lib/perf/tests/tests.h
new file mode 100644
index 000000000..604838f21
--- /dev/null
+++ b/tools/lib/perf/tests/tests.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef TESTS_H
+#define TESTS_H
+
+int test_cpumap(int argc, char **argv);
+int test_threadmap(int argc, char **argv);
+int test_evlist(int argc, char **argv);
+int test_evsel(int argc, char **argv);
+
+#endif /* TESTS_H */
diff --git a/tools/lib/perf/threadmap.c b/tools/lib/perf/threadmap.c
new file mode 100644
index 000000000..db431b036
--- /dev/null
+++ b/tools/lib/perf/threadmap.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <perf/threadmap.h>
+#include <stdlib.h>
+#include <linux/refcount.h>
+#include <internal/threadmap.h>
+#include <string.h>
+#include <asm/bug.h>
+#include <stdio.h>
+
+static void perf_thread_map__reset(struct perf_thread_map *map, int start, int nr)
+{
+	size_t size = (nr - start) * sizeof(map->map[0]);
+
+	memset(&map->map[start], 0, size);
+	map->err_thread = -1;
+}
+
+struct perf_thread_map *perf_thread_map__realloc(struct perf_thread_map *map, int nr)
+{
+	size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
+	int start = map ? map->nr : 0;
+
+	map = realloc(map, size);
+	/*
+	 * We only realloc to add more items, let's reset new items.
+	 */
+	if (map)
+		perf_thread_map__reset(map, start, nr);
+
+	return map;
+}
+
+#define thread_map__alloc(__nr) perf_thread_map__realloc(NULL, __nr)
+
+void perf_thread_map__set_pid(struct perf_thread_map *map, int idx, pid_t pid)
+{
+	map->map[idx].pid = pid;
+}
+
+char *perf_thread_map__comm(struct perf_thread_map *map, int idx)
+{
+	return map->map[idx].comm;
+}
+
+struct perf_thread_map *perf_thread_map__new_array(int nr_threads, pid_t *array)
+{
+	struct perf_thread_map *threads = thread_map__alloc(nr_threads);
+	int i;
+
+	if (!threads)
+		return NULL;
+
+	for (i = 0; i < nr_threads; i++)
+		perf_thread_map__set_pid(threads, i, array ? array[i] : -1);
+
+	threads->nr = nr_threads;
+	refcount_set(&threads->refcnt, 1);
+
+	return threads;
+}
+
+struct perf_thread_map *perf_thread_map__new_dummy(void)
+{
+	return perf_thread_map__new_array(1, NULL);
+}
+
+static void perf_thread_map__delete(struct perf_thread_map *threads)
+{
+	if (threads) {
+		int i;
+
+		WARN_ONCE(refcount_read(&threads->refcnt) != 0,
+			  "thread map refcnt unbalanced\n");
+		for (i = 0; i < threads->nr; i++)
+			free(perf_thread_map__comm(threads, i));
+		free(threads);
+	}
+}
+
+struct perf_thread_map *perf_thread_map__get(struct perf_thread_map *map)
+{
+	if (map)
+		refcount_inc(&map->refcnt);
+	return map;
+}
+
+void perf_thread_map__put(struct perf_thread_map *map)
+{
+	if (map && refcount_dec_and_test(&map->refcnt))
+		perf_thread_map__delete(map);
+}
+
+int perf_thread_map__nr(struct perf_thread_map *threads)
+{
+	return threads ? threads->nr : 1;
+}
+
+pid_t perf_thread_map__pid(struct perf_thread_map *map, int idx)
+{
+	if (!map) {
+		assert(idx == 0);
+		return -1;
+	}
+
+	return map->map[idx].pid;
+}
+
+int perf_thread_map__idx(struct perf_thread_map *threads, pid_t pid)
+{
+	if (!threads)
+		return pid == -1 ? 0 : -1;
+
+	for (int i = 0; i < threads->nr; ++i) {
+		if (threads->map[i].pid == pid)
+			return i;
+	}
+	return -1;
+}
diff --git a/tools/lib/perf/xyarray.c b/tools/lib/perf/xyarray.c
new file mode 100644
index 000000000..dcd901d15
--- /dev/null
+++ b/tools/lib/perf/xyarray.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <internal/xyarray.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size)
+{
+	size_t row_size = ylen * entry_size;
+	struct xyarray *xy = zalloc(sizeof(*xy) + xlen * row_size);
+
+	if (xy != NULL) {
+		xy->entry_size = entry_size;
+		xy->row_size   = row_size;
+		xy->entries    = xlen * ylen;
+		xy->max_x      = xlen;
+		xy->max_y      = ylen;
+	}
+
+	return xy;
+}
+
+void xyarray__reset(struct xyarray *xy)
+{
+	size_t n = xy->entries * xy->entry_size;
+
+	memset(xy->contents, 0, n);
+}
+
+void xyarray__delete(struct xyarray *xy)
+{
+	free(xy);
+}
diff --git a/tools/lib/python/__init__.py b/tools/lib/python/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tools/lib/python/__init__.py
diff --git a/tools/lib/python/abi/__init__.py b/tools/lib/python/abi/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tools/lib/python/abi/__init__.py
diff --git a/tools/lib/python/abi/abi_parser.py b/tools/lib/python/abi/abi_parser.py
new file mode 100644
index 000000000..d7bb20ef3
--- /dev/null
+++ b/tools/lib/python/abi/abi_parser.py
@@ -0,0 +1,631 @@
+#!/usr/bin/env python3
+# pylint: disable=R0902,R0903,R0911,R0912,R0913,R0914,R0915,R0917,C0302
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Parse ABI documentation and produce results from it.
+"""
+
+from argparse import Namespace
+import logging
+import os
+import re
+
+from pprint import pformat
+from random import randrange, seed
+
+# Import Python modules
+
+from abi.helpers import AbiDebug, ABI_DIR
+
+
+class AbiParser:
+    """Main class to parse ABI files."""
+
+    #: Valid tags at Documentation/ABI.
+    TAGS = r"(what|where|date|kernelversion|contact|description|users)"
+
+    #: ABI elements that will auto-generate cross-references.
+    XREF = r"(?:^|\s|\()(\/(?:sys|config|proc|dev|kvd)\/[^,.:;\)\s]+)(?:[,.:;\)\s]|\Z)"
+
+    def __init__(self, directory, logger=None,
+                 enable_lineno=False, show_warnings=True, debug=0):
+        """Stores arguments for the class and initialize class vars."""
+
+        self.directory = directory
+        self.enable_lineno = enable_lineno
+        self.show_warnings = show_warnings
+        self.debug = debug
+
+        if not logger:
+            self.log = logging.getLogger("get_abi")
+        else:
+            self.log = logger
+
+        self.data = {}
+        self.what_symbols = {}
+        self.file_refs = {}
+        self.what_refs = {}
+
+        # Ignore files that contain such suffixes
+        self.ignore_suffixes = (".rej", ".org", ".orig", ".bak", "~")
+
+        # Regular expressions used on parser
+        self.re_abi_dir = re.compile(r"(.*)" + ABI_DIR)
+        self.re_tag = re.compile(r"(\S+)(:\s*)(.*)", re.I)
+        self.re_valid = re.compile(self.TAGS)
+        self.re_start_spc = re.compile(r"(\s*)(\S.*)")
+        self.re_whitespace = re.compile(r"^\s+")
+
+        # Regular used on print
+        self.re_what = re.compile(r"(\/?(?:[\w\-]+\/?){1,2})")
+        self.re_escape = re.compile(r"([\.\x01-\x08\x0e-\x1f\x21-\x2f\x3a-\x40\x7b-\xff])")
+        self.re_unprintable = re.compile(r"([\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xff]+)")
+        self.re_title_mark = re.compile(r"\n[\-\*\=\^\~]+\n")
+        self.re_doc = re.compile(r"Documentation/(?!devicetree)(\S+)\.rst")
+        self.re_abi = re.compile(r"(Documentation/ABI/)([\w\/\-]+)")
+        self.re_xref_node = re.compile(self.XREF)
+
+    def warn(self, fdata, msg, extra=None):
+        """Displays a parse error if warning is enabled."""
+
+        if not self.show_warnings:
+            return
+
+        msg = f"{fdata.fname}:{fdata.ln}: {msg}"
+        if extra:
+            msg += "\n\t\t" + extra
+
+        self.log.warning(msg)
+
+    def add_symbol(self, what, fname, ln=None, xref=None):
+        """Create a reference table describing where each 'what' is located."""
+
+        if what not in self.what_symbols:
+            self.what_symbols[what] = {"file": {}}
+
+        if fname not in self.what_symbols[what]["file"]:
+            self.what_symbols[what]["file"][fname] = []
+
+        if ln and ln not in self.what_symbols[what]["file"][fname]:
+            self.what_symbols[what]["file"][fname].append(ln)
+
+        if xref:
+            self.what_symbols[what]["xref"] = xref
+
+    def _parse_line(self, fdata, line):
+        """Parse a single line of an ABI file."""
+
+        new_what = False
+        new_tag = False
+        content = None
+
+        match = self.re_tag.match(line)
+        if match:
+            new = match.group(1).lower()
+            sep = match.group(2)
+            content = match.group(3)
+
+            match = self.re_valid.search(new)
+            if match:
+                new_tag = match.group(1)
+            else:
+                if fdata.tag == "description":
+                    # New "tag" is actually part of description.
+                    # Don't consider it a tag
+                    new_tag = False
+                elif fdata.tag != "":
+                    self.warn(fdata, f"tag '{fdata.tag}' is invalid", line)
+
+        if new_tag:
+            # "where" is Invalid, but was a common mistake. Warn if found
+            if new_tag == "where":
+                self.warn(fdata, "tag 'Where' is invalid. Should be 'What:' instead")
+                new_tag = "what"
+
+            if new_tag == "what":
+                fdata.space = None
+
+                if content not in self.what_symbols:
+                    self.add_symbol(what=content, fname=fdata.fname, ln=fdata.ln)
+
+                if fdata.tag == "what":
+                    fdata.what.append(content.strip("\n"))
+                else:
+                    if fdata.key:
+                        if "description" not in self.data.get(fdata.key, {}):
+                            self.warn(fdata, f"{fdata.key} doesn't have a description")
+
+                        for w in fdata.what:
+                            self.add_symbol(what=w, fname=fdata.fname,
+                                            ln=fdata.what_ln, xref=fdata.key)
+
+                    fdata.label = content
+                    new_what = True
+
+                    key = "abi_" + content.lower()
+                    fdata.key = self.re_unprintable.sub("_", key).strip("_")
+
+                    # Avoid duplicated keys but using a defined seed, to make
+                    # the namespace identical if there aren't changes at the
+                    # ABI symbols
+                    seed(42)
+
+                    while fdata.key in self.data:
+                        char = randrange(0, 51) + ord("A")
+                        if char > ord("Z"):
+                            char += ord("a") - ord("Z") - 1
+
+                        fdata.key += chr(char)
+
+                    if fdata.key and fdata.key not in self.data:
+                        self.data[fdata.key] = {
+                            "what": [content],
+                            "file": [fdata.file_ref],
+                            "path": fdata.ftype,
+                            "line_no": fdata.ln,
+                        }
+
+                    fdata.what = self.data[fdata.key]["what"]
+
+                self.what_refs[content] = fdata.key
+                fdata.tag = new_tag
+                fdata.what_ln = fdata.ln
+
+                if fdata.nametag["what"]:
+                    t = (content, fdata.key)
+                    if t not in fdata.nametag["symbols"]:
+                        fdata.nametag["symbols"].append(t)
+
+                return
+
+            if fdata.tag and new_tag:
+                fdata.tag = new_tag
+
+                if new_what:
+                    fdata.label = ""
+
+                    if "description" in self.data[fdata.key]:
+                        self.data[fdata.key]["description"] += "\n\n"
+
+                    if fdata.file_ref not in self.data[fdata.key]["file"]:
+                        self.data[fdata.key]["file"].append(fdata.file_ref)
+
+                    if self.debug == AbiDebug.WHAT_PARSING:
+                        self.log.debug("what: %s", fdata.what)
+
+                if not fdata.what:
+                    self.warn(fdata, "'What:' should come first:", line)
+                    return
+
+                if new_tag == "description":
+                    fdata.space = None
+
+                    if content:
+                        sep = sep.replace(":", " ")
+
+                        c = " " * len(new_tag) + sep + content
+                        c = c.expandtabs()
+
+                        match = self.re_start_spc.match(c)
+                        if match:
+                            # Preserve initial spaces for the first line
+                            fdata.space = match.group(1)
+                            content = match.group(2) + "\n"
+
+                self.data[fdata.key][fdata.tag] = content
+
+            return
+
+        # Store any contents before tags at the database
+        if not fdata.tag and "what" in fdata.nametag:
+            fdata.nametag["description"] += line
+            return
+
+        if fdata.tag == "description":
+            content = line.expandtabs()
+
+            if self.re_whitespace.sub("", content) == "":
+                self.data[fdata.key][fdata.tag] += "\n"
+                return
+
+            if fdata.space is None:
+                match = self.re_start_spc.match(content)
+                if match:
+                    # Preserve initial spaces for the first line
+                    fdata.space = match.group(1)
+
+                    content = match.group(2) + "\n"
+            else:
+                if content.startswith(fdata.space):
+                    content = content[len(fdata.space):]
+
+                else:
+                    fdata.space = ""
+
+            if fdata.tag == "what":
+                w = content.strip("\n")
+                if w:
+                    self.data[fdata.key][fdata.tag].append(w)
+            else:
+                self.data[fdata.key][fdata.tag] += content
+            return
+
+        content = line.strip()
+        if fdata.tag:
+            if fdata.tag == "what":
+                w = content.strip("\n")
+                if w:
+                    self.data[fdata.key][fdata.tag].append(w)
+            else:
+                self.data[fdata.key][fdata.tag] += "\n" + content.rstrip("\n")
+            return
+
+        # Everything else is error
+        if content:
+            self.warn(fdata, "Unexpected content", line)
+
+    def parse_readme(self, nametag, fname):
+        """Parse ABI README file."""
+
+        nametag["what"] = ["Introduction"]
+        nametag["path"] = "README"
+        with open(fname, "r", encoding="utf8", errors="backslashreplace") as fp:
+            for line in fp:
+                match = self.re_tag.match(line)
+                if match:
+                    new = match.group(1).lower()
+
+                    match = self.re_valid.search(new)
+                    if match:
+                        nametag["description"] += "\n:" + line
+                        continue
+
+                nametag["description"] += line
+
+    def parse_file(self, fname, path, basename):
+        """Parse a single file."""
+
+        ref = f"abi_file_{path}_{basename}"
+        ref = self.re_unprintable.sub("_", ref).strip("_")
+
+        # Store per-file state into a namespace variable. This will be used
+        # by the per-line parser state machine and by the warning function.
+        fdata = Namespace
+
+        fdata.fname = fname
+        fdata.name = basename
+
+        pos = fname.find(ABI_DIR)
+        if pos > 0:
+            f = fname[pos:]
+        else:
+            f = fname
+
+        fdata.file_ref = (f, ref)
+        self.file_refs[f] = ref
+
+        fdata.ln = 0
+        fdata.what_ln = 0
+        fdata.tag = ""
+        fdata.label = ""
+        fdata.what = []
+        fdata.key = None
+        fdata.xrefs = None
+        fdata.space = None
+        fdata.ftype = path.split("/")[0]
+
+        fdata.nametag = {}
+        fdata.nametag["what"] = [f"ABI file {path}/{basename}"]
+        fdata.nametag["type"] = "File"
+        fdata.nametag["path"] = fdata.ftype
+        fdata.nametag["file"] = [fdata.file_ref]
+        fdata.nametag["line_no"] = 1
+        fdata.nametag["description"] = ""
+        fdata.nametag["symbols"] = []
+
+        self.data[ref] = fdata.nametag
+
+        if self.debug & AbiDebug.WHAT_OPEN:
+            self.log.debug("Opening file %s", fname)
+
+        if basename == "README":
+            self.parse_readme(fdata.nametag, fname)
+            return
+
+        with open(fname, "r", encoding="utf8", errors="backslashreplace") as fp:
+            for line in fp:
+                fdata.ln += 1
+
+                self._parse_line(fdata, line)
+
+            if "description" in fdata.nametag:
+                fdata.nametag["description"] = fdata.nametag["description"].lstrip("\n")
+
+            if fdata.key:
+                if "description" not in self.data.get(fdata.key, {}):
+                    self.warn(fdata, f"{fdata.key} doesn't have a description")
+
+                for w in fdata.what:
+                    self.add_symbol(what=w, fname=fname, xref=fdata.key)
+
+    def _parse_abi(self, root=None):
+        """Internal function to parse documentation ABI recursively."""
+
+        if not root:
+            root = self.directory
+
+        with os.scandir(root) as obj:
+            for entry in obj:
+                name = os.path.join(root, entry.name)
+
+                if entry.is_dir():
+                    self._parse_abi(name)
+                    continue
+
+                if not entry.is_file():
+                    continue
+
+                basename = os.path.basename(name)
+
+                if basename.startswith("."):
+                    continue
+
+                if basename.endswith(self.ignore_suffixes):
+                    continue
+
+                path = self.re_abi_dir.sub("", os.path.dirname(name))
+
+                self.parse_file(name, path, basename)
+
+    def parse_abi(self, root=None):
+        """Parse documentation ABI."""
+
+        self._parse_abi(root)
+
+        if self.debug & AbiDebug.DUMP_ABI_STRUCTS:
+            self.log.debug(pformat(self.data))
+
+    def desc_txt(self, desc):
+        """Print description as found inside ABI files."""
+
+        desc = desc.strip(" \t\n")
+
+        return desc + "\n\n"
+
+    def xref(self, fname):
+        """
+        Converts a Documentation/ABI + basename into a ReST cross-reference.
+        """
+
+        xref = self.file_refs.get(fname)
+        if not xref:
+            return None
+        else:
+            return xref
+
+    def desc_rst(self, desc):
+        """Enrich ReST output by creating cross-references."""
+
+        # Remove title markups from the description
+        # Having titles inside ABI files will only work if extra
+        # care would be taken in order to strictly follow the same
+        # level order for each markup.
+        desc = self.re_title_mark.sub("\n\n", "\n" + desc)
+        desc = desc.rstrip(" \t\n").lstrip("\n")
+
+        # Python's regex performance for non-compiled expressions is a lot
+        # than Perl, as Perl automatically caches them at their
+        # first usage. Here, we'll need to do the same, as otherwise the
+        # performance penalty is be high
+
+        new_desc = ""
+        for d in desc.split("\n"):
+            if d == "":
+                new_desc += "\n"
+                continue
+
+            # Use cross-references for doc files where needed
+            d = self.re_doc.sub(r":doc:`/\1`", d)
+
+            # Use cross-references for ABI generated docs where needed
+            matches = self.re_abi.findall(d)
+            for m in matches:
+                abi = m[0] + m[1]
+
+                xref = self.file_refs.get(abi)
+                if not xref:
+                    # This may happen if ABI is on a separate directory,
+                    # like parsing ABI testing and symbol is at stable.
+                    # The proper solution is to move this part of the code
+                    # for it to be inside sphinx/kernel_abi.py
+                    self.log.info("Didn't find ABI reference for '%s'", abi)
+                else:
+                    new = self.re_escape.sub(r"\\\1", m[1])
+                    d = re.sub(fr"\b{abi}\b", f":ref:`{new} <{xref}>`", d)
+
+            # Seek for cross reference symbols like /sys/...
+            # Need to be careful to avoid doing it on a code block
+            if d[0] not in [" ", "\t"]:
+                matches = self.re_xref_node.findall(d)
+                for m in matches:
+                    # Finding ABI here is more complex due to wildcards
+                    xref = self.what_refs.get(m)
+                    if xref:
+                        new = self.re_escape.sub(r"\\\1", m)
+                        d = re.sub(fr"\b{m}\b", f":ref:`{new} <{xref}>`", d)
+
+            new_desc += d + "\n"
+
+        return new_desc + "\n\n"
+
+    def doc(self, output_in_txt=False, show_symbols=True, show_file=True,
+            filter_path=None):
+        """Print ABI at stdout."""
+
+        part = None
+        for key, v in sorted(self.data.items(),
+                             key=lambda x: (x[1].get("type", ""),
+                                            x[1].get("what"))):
+
+            wtype = v.get("type", "Symbol")
+            file_ref = v.get("file")
+            names = v.get("what", [""])
+
+            if wtype == "File":
+                if not show_file:
+                    continue
+            else:
+                if not show_symbols:
+                    continue
+
+            if filter_path:
+                if v.get("path") != filter_path:
+                    continue
+
+            msg = ""
+
+            if wtype != "File":
+                cur_part = names[0]
+                if cur_part.find("/") >= 0:
+                    match = self.re_what.match(cur_part)
+                    if match:
+                        symbol = match.group(1).rstrip("/")
+                        cur_part = "Symbols under " + symbol
+
+                if cur_part and cur_part != part:
+                    part = cur_part
+                    msg += part + "\n"+ "-" * len(part) +"\n\n"
+
+                msg += f".. _{key}:\n\n"
+
+                max_len = 0
+                for i in range(0, len(names)):           # pylint: disable=C0200
+                    names[i] = "**" + self.re_escape.sub(r"\\\1", names[i]) + "**"
+
+                    max_len = max(max_len, len(names[i]))
+
+                msg += "+-" + "-" * max_len + "-+\n"
+                for name in names:
+                    msg += f"| {name}" + " " * (max_len - len(name)) + " |\n"
+                    msg += "+-" + "-" * max_len + "-+\n"
+                msg += "\n"
+
+            for ref in file_ref:
+                if wtype == "File":
+                    msg += f".. _{ref[1]}:\n\n"
+                else:
+                    base = os.path.basename(ref[0])
+                    msg += f"Defined on file :ref:`{base} <{ref[1]}>`\n\n"
+
+            if wtype == "File":
+                msg += names[0] +"\n" + "-" * len(names[0]) +"\n\n"
+
+            desc = v.get("description")
+            if not desc and wtype != "File":
+                msg += f"DESCRIPTION MISSING for {names[0]}\n\n"
+
+            if desc:
+                if output_in_txt:
+                    msg += self.desc_txt(desc)
+                else:
+                    msg += self.desc_rst(desc)
+
+            symbols = v.get("symbols")
+            if symbols:
+                msg += "Has the following ABI:\n\n"
+
+                for w, label in symbols:
+                    # Escape special chars from content
+                    content = self.re_escape.sub(r"\\\1", w)
+
+                    msg += f"- :ref:`{content} <{label}>`\n\n"
+
+            users = v.get("users")
+            if users and users.strip(" \t\n"):
+                users = users.strip("\n").replace('\n', '\n\t')
+                msg += f"Users:\n\t{users}\n\n"
+
+            ln = v.get("line_no", 1)
+
+            yield (msg, file_ref[0][0], ln)
+
+    def check_issues(self):
+        """Warn about duplicated ABI entries."""
+
+        for what, v in self.what_symbols.items():
+            files = v.get("file")
+            if not files:
+                # Should never happen if the parser works properly
+                self.log.warning("%s doesn't have a file associated", what)
+                continue
+
+            if len(files) == 1:
+                continue
+
+            f = []
+            for fname, lines in sorted(files.items()):
+                if not lines:
+                    f.append(f"{fname}")
+                elif len(lines) == 1:
+                    f.append(f"{fname}:{lines[0]}")
+                else:
+                    m = fname + "lines "
+                    m += ", ".join(str(x) for x in lines)
+                    f.append(m)
+
+            self.log.warning("%s is defined %d times: %s", what, len(f), "; ".join(f))
+
+    def search_symbols(self, expr):
+        """ Searches for ABI symbols."""
+
+        regex = re.compile(expr, re.I)
+
+        found_keys = 0
+        for t in sorted(self.data.items(), key=lambda x: [0]):
+            v = t[1]
+
+            wtype = v.get("type", "")
+            if wtype == "File":
+                continue
+
+            for what in v.get("what", [""]):
+                if regex.search(what):
+                    found_keys += 1
+
+                    kernelversion = v.get("kernelversion", "").strip(" \t\n")
+                    date = v.get("date", "").strip(" \t\n")
+                    contact = v.get("contact", "").strip(" \t\n")
+                    users = v.get("users", "").strip(" \t\n")
+                    desc = v.get("description", "").strip(" \t\n")
+
+                    files = []
+                    for f in v.get("file", ()):
+                        files.append(f[0])
+
+                    what = str(found_keys) + ". " + what
+                    title_tag = "-" * len(what)
+
+                    print(f"\n{what}\n{title_tag}\n")
+
+                    if kernelversion:
+                        print(f"Kernel version:\t\t{kernelversion}")
+
+                    if date:
+                        print(f"Date:\t\t\t{date}")
+
+                    if contact:
+                        print(f"Contact:\t\t{contact}")
+
+                    if users:
+                        print(f"Users:\t\t\t{users}")
+
+                    print("Defined on file(s):\t" + ", ".join(files))
+
+                    if desc:
+                        desc = desc.strip("\n")
+                        print(f"\n{desc}\n")
+
+        if not found_keys:
+            print(f"Regular expression /{expr}/ not found.")
diff --git a/tools/lib/python/abi/abi_regex.py b/tools/lib/python/abi/abi_regex.py
new file mode 100644
index 000000000..198ecbf49
--- /dev/null
+++ b/tools/lib/python/abi/abi_regex.py
@@ -0,0 +1,247 @@
+#!/usr/bin/env python3
+# xxpylint: disable=R0903
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Convert ABI what into regular expressions
+"""
+
+import re
+import sys
+
+from pprint import pformat
+
+from abi.abi_parser import AbiParser
+from abi.helpers import AbiDebug
+
+class AbiRegex(AbiParser):
+    """
+    Extends AbiParser to search ABI nodes with regular expressions.
+
+    There some optimizations here to allow a quick symbol search:
+    instead of trying to place all symbols altogether an doing linear
+    search which is very time consuming, create a tree with one depth,
+    grouping similar symbols altogether.
+
+    Yet, sometimes a full search will be needed, so we have a special branch
+    on such group tree where other symbols are placed.
+    """
+
+    #: Escape only ASCII visible characters.
+    escape_symbols = r"([\x21-\x29\x2b-\x2d\x3a-\x40\x5c\x60\x7b-\x7e])"
+
+    #: Special group for other nodes.
+    leave_others = "others"
+
+    # Tuples with regular expressions to be compiled and replacement data
+    re_whats = [
+        # Drop escape characters that might exist
+        (re.compile("\\\\"), ""),
+
+        # Temporarily escape dot characters
+        (re.compile(r"\."),  "\xf6"),
+
+        # Temporarily change [0-9]+ type of patterns
+        (re.compile(r"\[0\-9\]\+"),  "\xff"),
+
+        # Temporarily change [\d+-\d+] type of patterns
+        (re.compile(r"\[0\-\d+\]"),  "\xff"),
+        (re.compile(r"\[0:\d+\]"),  "\xff"),
+        (re.compile(r"\[(\d+)\]"),  "\xf4\\\\d+\xf5"),
+
+        # Temporarily change [0-9] type of patterns
+        (re.compile(r"\[(\d)\-(\d)\]"),  "\xf4\1-\2\xf5"),
+
+        # Handle multiple option patterns
+        (re.compile(r"[\{\<\[]([\w_]+)(?:[,|]+([\w_]+)){1,}[\}\>\]]"), r"(\1|\2)"),
+
+        # Handle wildcards
+        (re.compile(r"([^\/])\*"), "\\1\\\\w\xf7"),
+        (re.compile(r"/\*/"), "/.*/"),
+        (re.compile(r"/\xf6\xf6\xf6"), "/.*"),
+        (re.compile(r"\<[^\>]+\>"), "\\\\w\xf7"),
+        (re.compile(r"\{[^\}]+\}"), "\\\\w\xf7"),
+        (re.compile(r"\[[^\]]+\]"), "\\\\w\xf7"),
+
+        (re.compile(r"XX+"), "\\\\w\xf7"),
+        (re.compile(r"(?<![A-Z])[XYZ](?![A-Z])"), "\\\\w\xf7"),
+        (re.compile(r"_[AB]_"), "_\\\\w\xf7_"),
+
+        # Recover [0-9] type of patterns
+        (re.compile(r"\xf4"), "["),
+        (re.compile(r"\xf5"),  "]"),
+
+        # Remove duplicated spaces
+        (re.compile(r"\s+"), r" "),
+
+        # Special case: drop comparison as in:
+        # What: foo = <something>
+        # (this happens on a few IIO definitions)
+        (re.compile(r"\s*\=.*$"), ""),
+
+        # Escape all other symbols
+        (re.compile(escape_symbols), r"\\\1"),
+        (re.compile(r"\\\\"), r"\\"),
+        (re.compile(r"\\([\[\]\(\)\|])"), r"\1"),
+        (re.compile(r"(\d+)\\(-\d+)"), r"\1\2"),
+
+        (re.compile(r"\xff"), r"\\d+"),
+
+        # Special case: IIO ABI which a parenthesis.
+        (re.compile(r"sqrt(.*)"), r"sqrt(.*)"),
+
+        # Simplify regexes with multiple .*
+        (re.compile(r"(?:\.\*){2,}"),  ""),
+
+        # Recover dot characters
+        (re.compile(r"\xf6"), "\\."),
+        # Recover plus characters
+        (re.compile(r"\xf7"), "+"),
+    ]
+
+    #: Regex to check if the symbol name has a number on it.
+    re_has_num = re.compile(r"\\d")
+
+    #: Symbol name after escape_chars that are considered a devnode basename.
+    re_symbol_name =  re.compile(r"(\w|\\[\.\-\:])+$")
+
+    #: List of popular group names to be skipped to minimize regex group size
+    #: Use AbiDebug.SUBGROUP_SIZE to detect those.
+    skip_names = set(["devices", "hwmon"])
+
+    def regex_append(self, what, new):
+        """
+        Get a search group for a subset of regular expressions.
+
+        As ABI may have thousands of symbols, using a for to search all
+        regular expressions is at least O(n^2). When there are wildcards,
+        the complexity increases substantially, eventually becoming exponential.
+
+        To avoid spending too much time on them, use a logic to split
+        them into groups. The smaller the group, the better, as it would
+        mean that searches will be confined to a small number of regular
+        expressions.
+
+        The conversion to a regex subset is tricky, as we need something
+        that can be easily obtained from the sysfs symbol and from the
+        regular expression. So, we need to discard nodes that have
+        wildcards.
+
+        If it can't obtain a subgroup, place the regular expression inside
+        a special group (self.leave_others).
+        """
+
+        search_group = None
+
+        for search_group in reversed(new.split("/")):
+            if not search_group or search_group in self.skip_names:
+                continue
+            if self.re_symbol_name.match(search_group):
+                break
+
+        if not search_group:
+            search_group = self.leave_others
+
+        if self.debug & AbiDebug.SUBGROUP_MAP:
+            self.log.debug("%s: mapped as %s", what, search_group)
+
+        try:
+            if search_group not in self.regex_group:
+                self.regex_group[search_group] = []
+
+            self.regex_group[search_group].append(re.compile(new))
+            if self.search_string:
+                if what.find(self.search_string) >= 0:
+                    print(f"What: {what}")
+        except re.error:
+            self.log.warning("Ignoring '%s' as it produced an invalid regex:\n"
+                             "           '%s'", what, new)
+
+    def get_regexes(self, what):
+        """
+        Given an ABI devnode, return a list of all regular expressions that
+        may match it, based on the sub-groups created by regex_append().
+        """
+
+        re_list = []
+
+        patches = what.split("/")
+        patches.reverse()
+        patches.append(self.leave_others)
+
+        for search_group in patches:
+            if search_group in self.regex_group:
+                re_list += self.regex_group[search_group]
+
+        return re_list
+
+    def __init__(self, *args, **kwargs):
+        """
+        Override init method to get verbose argument
+        """
+
+        self.regex_group = None
+        self.search_string = None
+        self.re_string = None
+
+        if "search_string" in kwargs:
+            self.search_string = kwargs.get("search_string")
+            del kwargs["search_string"]
+
+            if self.search_string:
+
+                try:
+                    self.re_string = re.compile(self.search_string)
+                except re.error as e:
+                    msg = f"{self.search_string} is not a valid regular expression"
+                    raise ValueError(msg) from e
+
+        super().__init__(*args, **kwargs)
+
+    def parse_abi(self, *args, **kwargs):
+
+        super().parse_abi(*args, **kwargs)
+
+        self.regex_group = {}
+
+        print("Converting ABI What fields into regexes...", file=sys.stderr)
+
+        for t in sorted(self.data.items(), key=lambda x: x[0]):
+            v = t[1]
+            if v.get("type") == "File":
+                continue
+
+            v["regex"] = []
+
+            for what in v.get("what", []):
+                if not what.startswith("/sys"):
+                    continue
+
+                new = what
+                for r, s in self.re_whats:
+                    try:
+                        new = r.sub(s, new)
+                    except re.error as e:
+                        # Help debugging troubles with new regexes
+                        raise re.error(f"{e}\nwhile re.sub('{r.pattern}', {s}, str)") from e
+
+                v["regex"].append(new)
+
+                if self.debug & AbiDebug.REGEX:
+                    self.log.debug("%-90s <== %s", new, what)
+
+                # Store regex into a subgroup to speedup searches
+                self.regex_append(what, new)
+
+        if self.debug & AbiDebug.SUBGROUP_DICT:
+            self.log.debug("%s", pformat(self.regex_group))
+
+        if self.debug & AbiDebug.SUBGROUP_SIZE:
+            biggestd_keys = sorted(self.regex_group.keys(),
+                                   key= lambda k: len(self.regex_group[k]),
+                                   reverse=True)
+
+            print("Top regex subgroups:", file=sys.stderr)
+            for k in biggestd_keys[:10]:
+                print(f"{k} has {len(self.regex_group[k])} elements", file=sys.stderr)
diff --git a/tools/lib/python/abi/helpers.py b/tools/lib/python/abi/helpers.py
new file mode 100644
index 000000000..2a378d780
--- /dev/null
+++ b/tools/lib/python/abi/helpers.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+# pylint: disable=R0903
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Helper classes for ABI parser
+"""
+
+ABI_DIR = "Documentation/ABI/"
+
+
+class AbiDebug:
+    """Debug levels"""
+
+    WHAT_PARSING = 1        #: Enable debug parsing logic.
+    WHAT_OPEN = 2           #: Enable debug messages on file open.
+    DUMP_ABI_STRUCTS = 4    #: Enable debug for ABI parse data.
+    UNDEFINED = 8           #: Enable extra undefined symbol data.
+    REGEX = 16              #: Enable debug for what to regex conversion.
+    SUBGROUP_MAP = 32       #: Enable debug for symbol regex subgroups
+    SUBGROUP_DICT = 64      #: Enable debug for sysfs graph tree variable.
+    SUBGROUP_SIZE = 128     #: Enable debug of search groups.
+    GRAPH = 256             #: Display ref tree graph for undefined symbols.
+
+#: Helper messages for each debug variable
+DEBUG_HELP = """
+1   - enable debug parsing logic
+2   - enable debug messages on file open
+4   - enable debug for ABI parse data
+8   - enable extra debug information to identify troubles
+      with ABI symbols found at the local machine that
+      weren't found on ABI documentation (used only for
+      undefined subcommand)
+16  - enable debug for what to regex conversion
+32  - enable debug for symbol regex subgroups
+64  - enable debug for sysfs graph tree variable
+128 - enable debug of search groups
+256 - enable displaying refrence tree graphs for undefined symbols.
+"""
diff --git a/tools/lib/python/abi/system_symbols.py b/tools/lib/python/abi/system_symbols.py
new file mode 100644
index 000000000..7bbefd274
--- /dev/null
+++ b/tools/lib/python/abi/system_symbols.py
@@ -0,0 +1,378 @@
+#!/usr/bin/env python3
+# pylint: disable=R0902,R0912,R0914,R0915,R1702
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Parse ABI documentation and produce results from it.
+"""
+
+import os
+import re
+import sys
+
+from concurrent import futures
+from datetime import datetime
+from random import shuffle
+
+from abi.helpers import AbiDebug
+
+class SystemSymbols:
+    """Stores arguments for the class and initialize class vars."""
+
+    def graph_add_file(self, path, link=None):
+        """
+        add a file path to the sysfs graph stored at self.root.
+        """
+
+        if path in self.files:
+            return
+
+        name = ""
+        ref = self.root
+        for edge in path.split("/"):
+            name += edge + "/"
+            if edge not in ref:
+                ref[edge] = {"__name": [name.rstrip("/")]}
+
+            ref = ref[edge]
+
+        if link and link not in ref["__name"]:
+            ref["__name"].append(link.rstrip("/"))
+
+        self.files.add(path)
+
+    def print_graph(self, root_prefix="", root=None, level=0):
+        """Prints a reference tree graph using UTF-8 characters."""
+
+        if not root:
+            root = self.root
+            level = 0
+
+        # Prevent endless traverse
+        if level > 5:
+            return
+
+        if level > 0:
+            prefix = "├──"
+            last_prefix = "└──"
+        else:
+            prefix = ""
+            last_prefix = ""
+
+        items = list(root.items())
+
+        names = root.get("__name", [])
+        for k, edge in items:
+            if k == "__name":
+                continue
+
+            if not k:
+                k = "/"
+
+            if len(names) > 1:
+                k += " links: " + ",".join(names[1:])
+
+            if edge == items[-1][1]:
+                print(root_prefix + last_prefix + k)
+                p = root_prefix
+                if level > 0:
+                    p += "   "
+                self.print_graph(p, edge, level + 1)
+            else:
+                print(root_prefix + prefix + k)
+                p = root_prefix + "│   "
+                self.print_graph(p, edge, level + 1)
+
+    def _walk(self, root):
+        """
+        Walk through sysfs to get all devnodes that aren't ignored.
+
+        By default, uses /sys as sysfs mounting point. If another
+        directory is used, it replaces them to /sys at the patches.
+        """
+
+        with os.scandir(root) as obj:
+            for entry in obj:
+                path = os.path.join(root, entry.name)
+                if self.sysfs:
+                    p = path.replace(self.sysfs, "/sys", count=1)
+                else:
+                    p = path
+
+                if self.re_ignore.search(p):
+                    return
+
+                # Handle link first to avoid directory recursion
+                if entry.is_symlink():
+                    real = os.path.realpath(path)
+                    if not self.sysfs:
+                        self.aliases[path] = real
+                    else:
+                        real = real.replace(self.sysfs, "/sys", count=1)
+
+                    # Add absfile location to graph if it doesn't exist
+                    if not self.re_ignore.search(real):
+                        # Add link to the graph
+                        self.graph_add_file(real, p)
+
+                elif entry.is_file():
+                    self.graph_add_file(p)
+
+                elif entry.is_dir():
+                    self._walk(path)
+
+    def __init__(self, abi, sysfs="/sys", hints=False):
+        """
+        Initialize internal variables and get a list of all files inside
+        sysfs that can currently be parsed.
+
+        Please notice that there are several entries on sysfs that aren't
+        documented as ABI. Ignore those.
+
+        The real paths will be stored under self.files. Aliases will be
+        stored in separate, as self.aliases.
+        """
+
+        self.abi = abi
+        self.log = abi.log
+
+        if sysfs != "/sys":
+            self.sysfs = sysfs.rstrip("/")
+        else:
+            self.sysfs = None
+
+        self.hints = hints
+
+        self.root = {}
+        self.aliases = {}
+        self.files = set()
+
+        dont_walk = [
+            # Those require root access and aren't documented at ABI
+            f"^{sysfs}/kernel/debug",
+            f"^{sysfs}/kernel/tracing",
+            f"^{sysfs}/fs/pstore",
+            f"^{sysfs}/fs/bpf",
+            f"^{sysfs}/fs/fuse",
+
+            # This is not documented at ABI
+            f"^{sysfs}/module",
+
+            f"^{sysfs}/fs/cgroup",  # this is big and has zero docs under ABI
+            f"^{sysfs}/firmware",   # documented elsewhere: ACPI, DT bindings
+            "sections|notes",       # aren't actually part of ABI
+
+            # kernel-parameters.txt - not easy to parse
+            "parameters",
+        ]
+
+        self.re_ignore = re.compile("|".join(dont_walk))
+
+        print(f"Reading {sysfs} directory contents...", file=sys.stderr)
+        self._walk(sysfs)
+
+    def check_file(self, refs, found):
+        """Check missing ABI symbols for a given sysfs file."""
+
+        res_list = []
+
+        try:
+            for names in refs:
+                fname = names[0]
+
+                res = {
+                    "found": False,
+                    "fname": fname,
+                    "msg": "",
+                }
+                res_list.append(res)
+
+                re_what = self.abi.get_regexes(fname)
+                if not re_what:
+                    self.abi.log.warning(f"missing rules for {fname}")
+                    continue
+
+                for name in names:
+                    for r in re_what:
+                        if self.abi.debug & AbiDebug.UNDEFINED:
+                            self.log.debug("check if %s matches '%s'", name, r.pattern)
+                        if r.match(name):
+                            res["found"] = True
+                            if found:
+                                res["msg"] += f"  {fname}: regex:\n\t"
+                            continue
+
+                if self.hints and not res["found"]:
+                    res["msg"] += f"  {fname} not found. Tested regexes:\n"
+                    for r in re_what:
+                        res["msg"] += "    " + r.pattern + "\n"
+
+        except KeyboardInterrupt:
+            pass
+
+        return res_list
+
+    def _ref_interactor(self, root):
+        """Recursive function to interact over the sysfs tree."""
+
+        for k, v in root.items():
+            if isinstance(v, dict):
+                yield from self._ref_interactor(v)
+
+            if root == self.root or k == "__name":
+                continue
+
+            if self.abi.re_string:
+                fname = v["__name"][0]
+                if self.abi.re_string.search(fname):
+                    yield v
+            else:
+                yield v
+
+
+    def get_fileref(self, all_refs, chunk_size):
+        """Interactor to group refs into chunks."""
+
+        n = 0
+        refs = []
+
+        for ref in all_refs:
+            refs.append(ref)
+
+            n += 1
+            if n >= chunk_size:
+                yield refs
+                n = 0
+                refs = []
+
+        yield refs
+
+    def check_undefined_symbols(self, max_workers=None, chunk_size=50,
+                                found=None, dry_run=None):
+        """Seach ABI for sysfs symbols missing documentation."""
+
+        self.abi.parse_abi()
+
+        if self.abi.debug & AbiDebug.GRAPH:
+            self.print_graph()
+
+        all_refs = []
+        for ref in self._ref_interactor(self.root):
+            all_refs.append(ref["__name"])
+
+        if dry_run:
+            print("Would check", file=sys.stderr)
+            for ref in all_refs:
+                print(", ".join(ref))
+
+            return
+
+        print("Starting to search symbols (it may take several minutes):",
+              file=sys.stderr)
+        start = datetime.now()
+        old_elapsed = None
+
+        # Python doesn't support multithreading due to limitations on its
+        # global lock (GIL). While Python 3.13 finally made GIL optional,
+        # there are still issues related to it. Also, we want to have
+        # backward compatibility with older versions of Python.
+        #
+        # So, use instead multiprocess. However, Python is very slow passing
+        # data from/to multiple processes. Also, it may consume lots of memory
+        # if the data to be shared is not small.  So, we need to group workload
+        # in chunks that are big enough to generate performance gains while
+        # not being so big that would cause out-of-memory.
+
+        num_refs = len(all_refs)
+        print(f"Number of references to parse: {num_refs}", file=sys.stderr)
+
+        if not max_workers:
+            max_workers = os.cpu_count()
+        elif max_workers > os.cpu_count():
+            max_workers = os.cpu_count()
+
+        max_workers = max(max_workers, 1)
+
+        max_chunk_size = int((num_refs + max_workers - 1) / max_workers)
+        chunk_size = min(chunk_size, max_chunk_size)
+        chunk_size = max(1, chunk_size)
+
+        if max_workers > 1:
+            executor = futures.ProcessPoolExecutor
+
+            # Place references in a random order. This may help improving
+            # performance, by mixing complex/simple expressions when creating
+            # chunks
+            shuffle(all_refs)
+        else:
+            # Python has a high overhead with processes. When there's just
+            # one worker, it is faster to not create a new process.
+            # Yet, User still deserves to have a progress print. So, use
+            # python's "thread", which is actually a single process, using
+            # an internal schedule to switch between tasks. No performance
+            # gains for non-IO tasks, but still it can be quickly interrupted
+            # from time to time to display progress.
+            executor = futures.ThreadPoolExecutor
+
+        not_found = []
+        f_list = []
+        with executor(max_workers=max_workers) as exe:
+            for refs in self.get_fileref(all_refs, chunk_size):
+                if refs:
+                    try:
+                        f_list.append(exe.submit(self.check_file, refs, found))
+
+                    except KeyboardInterrupt:
+                        return
+
+            total = len(f_list)
+
+            if not total:
+                if self.abi.re_string:
+                    print(f"No ABI symbol matches {self.abi.search_string}")
+                else:
+                    self.abi.log.warning("No ABI symbols found")
+                return
+
+            print(f"{len(f_list):6d} jobs queued on {max_workers} workers",
+                  file=sys.stderr)
+
+            while f_list:
+                try:
+                    t = futures.wait(f_list, timeout=1,
+                                     return_when=futures.FIRST_COMPLETED)
+
+                    done = t[0]
+
+                    for fut in done:
+                        res_list = fut.result()
+
+                        for res in res_list:
+                            if not res["found"]:
+                                not_found.append(res["fname"])
+                            if res["msg"]:
+                                print(res["msg"])
+
+                        f_list.remove(fut)
+                except KeyboardInterrupt:
+                    return
+
+                except RuntimeError as e:
+                    self.abi.log.warning(f"Future: {e}")
+                    break
+
+                if sys.stderr.isatty():
+                    elapsed = str(datetime.now() - start).split(".", maxsplit=1)[0]
+                    if len(f_list) < total:
+                        elapsed += f" ({total - len(f_list)}/{total} jobs completed).  "
+                    if elapsed != old_elapsed:
+                        print(elapsed + "\r", end="", flush=True,
+                              file=sys.stderr)
+                        old_elapsed = elapsed
+
+        elapsed = str(datetime.now() - start).split(".", maxsplit=1)[0]
+        print(elapsed, file=sys.stderr)
+
+        for f in sorted(not_found):
+            print(f"{f} not found.")
diff --git a/tools/lib/python/feat/parse_features.py b/tools/lib/python/feat/parse_features.py
new file mode 100755
index 000000000..41a51d9d6
--- /dev/null
+++ b/tools/lib/python/feat/parse_features.py
@@ -0,0 +1,507 @@
+#!/usr/bin/env python3
+# pylint: disable=R0902,R0911,R0912,R0914,R0915
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+# SPDX-License-Identifier: GPL-2.0
+
+
+"""
+Library to parse the Linux Feature files and produce a ReST book.
+"""
+
+import os
+import re
+import sys
+
+from glob import iglob
+
+
+class ParseFeature:
+    """
+    Parses Documentation/features, allowing to generate ReST documentation
+    from it.
+    """
+
+    #: feature header string.
+    h_name = "Feature"
+
+    #: Kernel config header string.
+    h_kconfig = "Kconfig"
+
+    #: description header string.
+    h_description = "Description"
+
+    #: subsystem header string.
+    h_subsys = "Subsystem"
+
+    #: status header string.
+    h_status = "Status"
+
+    #: architecture header string.
+    h_arch = "Architecture"
+
+    #: Sort order for status. Others will be mapped at the end.
+    status_map = {
+        "ok":   0,
+        "TODO": 1,
+        "N/A":  2,
+        # The only missing status is "..", which was mapped as "---",
+        # as this is an special ReST cell value. Let it get the
+        # default order (99).
+    }
+
+    def __init__(self, prefix, debug=0, enable_fname=False):
+        """
+        Sets internal variables.
+        """
+
+        self.prefix = prefix
+        self.debug = debug
+        self.enable_fname = enable_fname
+
+        self.data = {}
+
+        # Initial maximum values use just the headers
+        self.max_size_name = len(self.h_name)
+        self.max_size_kconfig = len(self.h_kconfig)
+        self.max_size_description = len(self.h_description)
+        self.max_size_desc_word = 0
+        self.max_size_subsys = len(self.h_subsys)
+        self.max_size_status = len(self.h_status)
+        self.max_size_arch = len(self.h_arch)
+        self.max_size_arch_with_header = self.max_size_arch + self.max_size_arch
+        self.description_size = 1
+
+        self.msg = ""
+
+    def emit(self, msg="", end="\n"):
+        """Helper function to append a new message for feature output."""
+
+        self.msg += msg + end
+
+    def parse_error(self, fname, ln, msg, data=None):
+        """
+        Displays an error message, printing file name and line.
+        """
+
+        if ln:
+            fname += f"#{ln}"
+
+        print(f"Warning: file {fname}: {msg}", file=sys.stderr, end="")
+
+        if data:
+            data = data.rstrip()
+            print(f":\n\t{data}", file=sys.stderr)
+        else:
+            print("", file=sys.stderr)
+
+    def parse_feat_file(self, fname):
+        """Parses a single arch-support.txt feature file."""
+
+        if os.path.isdir(fname):
+            return
+
+        base = os.path.basename(fname)
+
+        if base != "arch-support.txt":
+            if self.debug:
+                print(f"ignoring {fname}", file=sys.stderr)
+            return
+
+        subsys = os.path.dirname(fname).split("/")[-2]
+        self.max_size_subsys = max(self.max_size_subsys, len(subsys))
+
+        feature_name = ""
+        kconfig = ""
+        description = ""
+        comments = ""
+        arch_table = {}
+
+        if self.debug > 1:
+            print(f"Opening {fname}", file=sys.stderr)
+
+        if self.enable_fname:
+            full_fname = os.path.abspath(fname)
+            self.emit(f".. FILE {full_fname}")
+
+        with open(fname, encoding="utf-8") as f:
+            for ln, line in enumerate(f, start=1):
+                line = line.strip()
+
+                match = re.match(r"^\#\s+Feature\s+name:\s*(.*\S)", line)
+                if match:
+                    feature_name = match.group(1)
+
+                    self.max_size_name = max(self.max_size_name,
+                                             len(feature_name))
+                    continue
+
+                match = re.match(r"^\#\s+Kconfig:\s*(.*\S)", line)
+                if match:
+                    kconfig = match.group(1)
+
+                    self.max_size_kconfig = max(self.max_size_kconfig,
+                                                len(kconfig))
+                    continue
+
+                match = re.match(r"^\#\s+description:\s*(.*\S)", line)
+                if match:
+                    description = match.group(1)
+
+                    self.max_size_description = max(self.max_size_description,
+                                                    len(description))
+
+                    words = re.split(r"\s+", line)[1:]
+                    for word in words:
+                        self.max_size_desc_word = max(self.max_size_desc_word,
+                                                        len(word))
+
+                    continue
+
+                if re.search(r"^\\s*$", line):
+                    continue
+
+                if re.match(r"^\s*\-+\s*$", line):
+                    continue
+
+                if re.search(r"^\s*\|\s*arch\s*\|\s*status\s*\|\s*$", line):
+                    continue
+
+                match = re.match(r"^\#\s*(.*)$", line)
+                if match:
+                    comments += match.group(1)
+                    continue
+
+                match = re.match(r"^\s*\|\s*(\S+):\s*\|\s*(\S+)\s*\|\s*$", line)
+                if match:
+                    arch = match.group(1)
+                    status = match.group(2)
+
+                    self.max_size_status = max(self.max_size_status,
+                                               len(status))
+                    self.max_size_arch = max(self.max_size_arch, len(arch))
+
+                    if status == "..":
+                        status = "---"
+
+                    arch_table[arch] = status
+
+                    continue
+
+                self.parse_error(fname, ln, "Line is invalid", line)
+
+        if not feature_name:
+            self.parse_error(fname, 0, "Feature name not found")
+            return
+        if not subsys:
+            self.parse_error(fname, 0, "Subsystem not found")
+            return
+        if not kconfig:
+            self.parse_error(fname, 0, "Kconfig not found")
+            return
+        if not description:
+            self.parse_error(fname, 0, "Description not found")
+            return
+        if not arch_table:
+            self.parse_error(fname, 0, "Architecture table not found")
+            return
+
+        self.data[feature_name] = {
+            "where": fname,
+            "subsys": subsys,
+            "kconfig": kconfig,
+            "description": description,
+            "comments": comments,
+            "table": arch_table,
+        }
+
+        self.max_size_arch_with_header = self.max_size_arch + len(self.h_arch)
+
+    def parse(self):
+        """Parses all arch-support.txt feature files inside self.prefix."""
+
+        path = os.path.expanduser(self.prefix)
+
+        if self.debug > 2:
+            print(f"Running parser for {path}")
+
+        example_path = os.path.join(path, "arch-support.txt")
+
+        for fname in iglob(os.path.join(path, "**"), recursive=True):
+            if fname != example_path:
+                self.parse_feat_file(fname)
+
+        return self.data
+
+    def output_arch_table(self, arch, feat=None):
+        """
+        Output feature(s) for a given architecture.
+        """
+
+        title = f"Feature status on {arch} architecture"
+
+        self.emit("=" * len(title))
+        self.emit(title)
+        self.emit("=" * len(title))
+        self.emit()
+
+        self.emit("=" * self.max_size_subsys + "  ", end="")
+        self.emit("=" * self.max_size_name + "  ", end="")
+        self.emit("=" * self.max_size_kconfig + "  ", end="")
+        self.emit("=" * self.max_size_status + "  ", end="")
+        self.emit("=" * self.max_size_description)
+
+        self.emit(f"{self.h_subsys:<{self.max_size_subsys}}  ", end="")
+        self.emit(f"{self.h_name:<{self.max_size_name}}  ", end="")
+        self.emit(f"{self.h_kconfig:<{self.max_size_kconfig}}  ", end="")
+        self.emit(f"{self.h_status:<{self.max_size_status}}  ", end="")
+        self.emit(f"{self.h_description:<{self.max_size_description}}")
+
+        self.emit("=" * self.max_size_subsys + "  ", end="")
+        self.emit("=" * self.max_size_name + "  ", end="")
+        self.emit("=" * self.max_size_kconfig + "  ", end="")
+        self.emit("=" * self.max_size_status + "  ", end="")
+        self.emit("=" * self.max_size_description)
+
+        sorted_features = sorted(self.data.keys(),
+                                 key=lambda x: (self.data[x]["subsys"],
+                                                x.lower()))
+
+        for name in sorted_features:
+            if feat and name != feat:
+                continue
+
+            arch_table = self.data[name]["table"]
+
+            if not arch in arch_table:
+                continue
+
+            self.emit(f"{self.data[name]['subsys']:<{self.max_size_subsys}}  ",
+                  end="")
+            self.emit(f"{name:<{self.max_size_name}}  ", end="")
+            self.emit(f"{self.data[name]['kconfig']:<{self.max_size_kconfig}}  ",
+                  end="")
+            self.emit(f"{arch_table[arch]:<{self.max_size_status}}  ",
+                  end="")
+            self.emit(f"{self.data[name]['description']}")
+
+        self.emit("=" * self.max_size_subsys + "  ", end="")
+        self.emit("=" * self.max_size_name + "  ", end="")
+        self.emit("=" * self.max_size_kconfig + "  ", end="")
+        self.emit("=" * self.max_size_status + "  ", end="")
+        self.emit("=" * self.max_size_description)
+
+        return self.msg
+
+    def output_feature(self, feat):
+        """
+        Output a feature on all architectures.
+        """
+
+        title = f"Feature {feat}"
+
+        self.emit("=" * len(title))
+        self.emit(title)
+        self.emit("=" * len(title))
+        self.emit()
+
+        if not feat in self.data:
+            return
+
+        if self.data[feat]["subsys"]:
+            self.emit(f":Subsystem: {self.data[feat]['subsys']}")
+        if self.data[feat]["kconfig"]:
+            self.emit(f":Kconfig: {self.data[feat]['kconfig']}")
+
+        desc = self.data[feat]["description"]
+        desc = desc[0].upper() + desc[1:]
+        desc = desc.rstrip(". \t")
+        self.emit(f"\n{desc}.\n")
+
+        com = self.data[feat]["comments"].strip()
+        if com:
+            self.emit("Comments")
+            self.emit("--------")
+            self.emit(f"\n{com}\n")
+
+        self.emit("=" * self.max_size_arch + "  ", end="")
+        self.emit("=" * self.max_size_status)
+
+        self.emit(f"{self.h_arch:<{self.max_size_arch}}  ", end="")
+        self.emit(f"{self.h_status:<{self.max_size_status}}")
+
+        self.emit("=" * self.max_size_arch + "  ", end="")
+        self.emit("=" * self.max_size_status)
+
+        arch_table = self.data[feat]["table"]
+        for arch in sorted(arch_table.keys()):
+            self.emit(f"{arch:<{self.max_size_arch}}  ", end="")
+            self.emit(f"{arch_table[arch]:<{self.max_size_status}}")
+
+        self.emit("=" * self.max_size_arch + "  ", end="")
+        self.emit("=" * self.max_size_status)
+
+        return self.msg
+
+    def matrix_lines(self, desc_size, max_size_status, header):
+        """
+        Helper function to split element tables at the output matrix.
+        """
+
+        if header:
+            ln_marker = "="
+        else:
+            ln_marker = "-"
+
+        self.emit("+" + ln_marker * self.max_size_name + "+", end="")
+        self.emit(ln_marker * desc_size, end="")
+        self.emit("+" + ln_marker * max_size_status + "+")
+
+    def output_matrix(self):
+        """
+        Generates a set of tables, groped by subsystem, containing
+        what's the feature state on each architecture.
+        """
+
+        title = "Feature status on all architectures"
+
+        self.emit("=" * len(title))
+        self.emit(title)
+        self.emit("=" * len(title))
+        self.emit()
+
+        desc_title = f"{self.h_kconfig} / {self.h_description}"
+
+        desc_size = self.max_size_kconfig + 4
+        if not self.description_size:
+            desc_size = max(self.max_size_description, desc_size)
+        else:
+            desc_size = max(self.description_size, desc_size)
+
+        desc_size = max(self.max_size_desc_word, desc_size, len(desc_title))
+
+        notcompat = "Not compatible"
+        self.max_size_status = max(self.max_size_status, len(notcompat))
+
+        min_status_size = self.max_size_status + self.max_size_arch + 4
+        max_size_status = max(min_status_size, self.max_size_status)
+
+        h_status_per_arch = "Status per architecture"
+        max_size_status = max(max_size_status, len(h_status_per_arch))
+
+        cur_subsys = None
+        for name in sorted(self.data.keys(),
+                           key=lambda x: (self.data[x]["subsys"], x.lower())):
+            if not cur_subsys or cur_subsys != self.data[name]["subsys"]:
+                if cur_subsys:
+                    self.emit()
+
+                cur_subsys = self.data[name]["subsys"]
+
+                title = f"Subsystem: {cur_subsys}"
+                self.emit(title)
+                self.emit("=" * len(title))
+                self.emit()
+
+                self.matrix_lines(desc_size, max_size_status, 0)
+
+                self.emit(f"|{self.h_name:<{self.max_size_name}}", end="")
+                self.emit(f"|{desc_title:<{desc_size}}", end="")
+                self.emit(f"|{h_status_per_arch:<{max_size_status}}|")
+
+                self.matrix_lines(desc_size, max_size_status, 1)
+
+            lines = []
+            descs = []
+            cur_status = ""
+            line = ""
+
+            arch_table = sorted(self.data[name]["table"].items(),
+                                key=lambda x: (self.status_map.get(x[1], 99),
+                                               x[0].lower()))
+
+            for arch, status in arch_table:
+                if status == "---":
+                    status = notcompat
+
+                if status != cur_status:
+                    if line != "":
+                        lines.append(line)
+                        line = ""
+                    line = f"- **{status}**: {arch}"
+                elif len(line) + len(arch) + 2 < max_size_status:
+                    line += f", {arch}"
+                else:
+                    lines.append(line)
+                    line = f"  {arch}"
+                cur_status = status
+
+            if line != "":
+                lines.append(line)
+
+            description = self.data[name]["description"]
+            while len(description) > desc_size:
+                desc_line = description[:desc_size]
+
+                last_space = desc_line.rfind(" ")
+                if last_space != -1:
+                    desc_line = desc_line[:last_space]
+                    descs.append(desc_line)
+                    description = description[last_space + 1:]
+                else:
+                    desc_line = desc_line[:-1]
+                    descs.append(desc_line + "\\")
+                    description = description[len(desc_line):]
+
+            if description:
+                descs.append(description)
+
+            while len(lines) < 2 + len(descs):
+                lines.append("")
+
+            for ln, line in enumerate(lines):
+                col = ["", ""]
+
+                if not ln:
+                    col[0] = name
+                    col[1] = f"``{self.data[name]['kconfig']}``"
+                else:
+                    if ln >= 2 and descs:
+                        col[1] = descs.pop(0)
+
+                self.emit(f"|{col[0]:<{self.max_size_name}}", end="")
+                self.emit(f"|{col[1]:<{desc_size}}", end="")
+                self.emit(f"|{line:<{max_size_status}}|")
+
+            self.matrix_lines(desc_size, max_size_status, 0)
+
+        return self.msg
+
+    def list_arch_features(self, arch, feat):
+        """
+        Print a matrix of kernel feature support for the chosen architecture.
+        """
+        self.emit("#")
+        self.emit(f"# Kernel feature support matrix of the '{arch}' architecture:")
+        self.emit("#")
+
+        # Sort by subsystem, then by feature name (case‑insensitive)
+        for name in sorted(self.data.keys(),
+                           key=lambda n: (self.data[n]["subsys"].lower(),
+                                          n.lower())):
+            if feat and name != feat:
+                continue
+
+            feature = self.data[name]
+            arch_table = feature["table"]
+            status = arch_table.get(arch, "")
+            status = " " * ((4 - len(status)) // 2) + status
+
+            self.emit(f"{feature['subsys']:>{self.max_size_subsys + 1}}/ ",
+                      end="")
+            self.emit(f"{name:<{self.max_size_name}}: ", end="")
+            self.emit(f"{status:<5}|   ", end="")
+            self.emit(f"{feature['kconfig']:>{self.max_size_kconfig}} ",
+                      end="")
+            self.emit(f"#  {feature['description']}")
+
+        return self.msg
diff --git a/tools/lib/python/jobserver.py b/tools/lib/python/jobserver.py
new file mode 100755
index 000000000..0b1ffdf9f
--- /dev/null
+++ b/tools/lib/python/jobserver.py
@@ -0,0 +1,195 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0+
+#
+# pylint: disable=C0103,C0209
+#
+#
+
+"""
+Interacts with the POSIX jobserver during the Kernel build time.
+
+A "normal" jobserver task, like the one initiated by a make subprocess would do:
+
+    - open read/write file descriptors to communicate with the job server;
+    - ask for one slot by calling::
+
+        claim = os.read(reader, 1)
+
+    - when the job finishes, call::
+
+        os.write(writer, b"+")  # os.write(writer, claim)
+
+Here, the goal is different: This script aims to get the remaining number
+of slots available, using all of them to run a command which handle tasks in
+parallel. To to that, it has a loop that ends only after there are no
+slots left. It then increments the number by one, in order to allow a
+call equivalent to ``make -j$((claim+1))``, e.g. having a parent make creating
+$claim child to do the actual work.
+
+The end goal here is to keep the total number of build tasks under the
+limit established by the initial ``make -j$n_proc`` call.
+
+See:
+    https://www.gnu.org/software/make/manual/html_node/POSIX-Jobserver.html#POSIX-Jobserver
+"""
+
+import errno
+import os
+import subprocess
+import sys
+
+def warn(text, *args):
+    print(f'WARNING: {text}', *args, file = sys.stderr)
+
+class JobserverExec:
+    """
+    Claim all slots from make using POSIX Jobserver.
+
+    The main methods here are:
+
+    - open(): reserves all slots;
+    - close(): method returns all used slots back to make;
+    - run(): executes a command setting PARALLELISM=<available slots jobs + 1>.
+    """
+
+    def __init__(self):
+        """Initialize internal vars."""
+        self.claim = 0
+        self.jobs = b""
+        self.reader = None
+        self.writer = None
+        self.is_open = False
+
+    def open(self):
+        """Reserve all available slots to be claimed later on."""
+
+        if self.is_open:
+            return
+        self.is_open = True  # We only try once
+        self.claim = None
+        #
+        # Check the make flags for "--jobserver=R,W"
+        # Note that GNU Make has used --jobserver-fds and --jobserver-auth
+        # so this handles all of them.
+        #
+        flags = os.environ.get('MAKEFLAGS', '')
+        opts = [x for x in flags.split(" ") if x.startswith("--jobserver")]
+        if not opts:
+            return
+        #
+        # Separate out the provided file descriptors
+        #
+        split_opt = opts[-1].split('=', 1)
+        if len(split_opt) != 2:
+            warn('unparseable option:', opts[-1])
+            return
+        fds = split_opt[1]
+        #
+        # As of GNU Make 4.4, we'll be looking for a named pipe
+        # identified as fifo:path
+        #
+        if fds.startswith('fifo:'):
+            path = fds[len('fifo:'):]
+            try:
+                self.reader = os.open(path, os.O_RDONLY | os.O_NONBLOCK)
+                self.writer = os.open(path, os.O_WRONLY)
+            except (OSError, IOError):
+                warn('unable to open jobserver pipe', path)
+                return
+        #
+        # Otherwise look for integer file-descriptor numbers.
+        #
+        else:
+            split_fds = fds.split(',')
+            if len(split_fds) != 2:
+                warn('malformed jobserver file descriptors:', fds)
+                return
+            try:
+                self.reader = int(split_fds[0])
+                self.writer = int(split_fds[1])
+            except ValueError:
+                warn('non-integer jobserver file-descriptors:', fds)
+                return
+            try:
+                #
+                # Open a private copy of reader to avoid setting nonblocking
+                # on an unexpecting process with the same reader fd.
+                #
+                self.reader = os.open(f"/proc/self/fd/{self.reader}",
+                                      os.O_RDONLY | os.O_NONBLOCK)
+            except (IOError, OSError) as e:
+                warn('Unable to reopen jobserver read-side pipe:', repr(e))
+                return
+        #
+        # OK, we have the channel to the job server; read out as many jobserver
+        # slots as possible.
+        #
+        while True:
+            try:
+                slot = os.read(self.reader, 8)
+                if not slot:
+                    #
+                    # Something went wrong.  Clear self.jobs to avoid writing
+                    # weirdness back to the jobserver and give up.
+                    self.jobs = b""
+                    warn("unexpected empty token from jobserver;"
+                         " possible invalid '--jobserver-auth=' setting")
+                    self.claim = None
+                    return
+            except (OSError, IOError) as e:
+                #
+                # If there is nothing more to read then we are done.
+                #
+                if e.errno == errno.EWOULDBLOCK:
+                    break
+                #
+                # Anything else says that something went weird; give back
+                # the jobs and give up.
+                #
+                if self.jobs:
+                    os.write(self.writer, self.jobs)
+                    self.claim = None
+                    warn('error reading from jobserver pipe', repr(e))
+                    return
+            self.jobs += slot
+        #
+        # Add a bump for our caller's reserveration, since we're just going
+        # to sit here blocked on our child.
+        #
+        self.claim = len(self.jobs) + 1
+
+    def close(self):
+        """Return all reserved slots to Jobserver."""
+
+        if not self.is_open:
+            return
+
+        # Return all the reserved slots.
+        if len(self.jobs):
+            os.write(self.writer, self.jobs)
+
+        self.is_open = False
+
+    def __enter__(self):
+        self.open()
+        return self
+
+    def __exit__(self, exc_type, exc_value, exc_traceback):
+        self.close()
+
+    def run(self, cmd, *args, **pwargs):
+        """
+        Run a command setting PARALLELISM env variable to the number of
+        available job slots (claim) + 1, e.g. it will reserve claim slots
+        to do the actual build work, plus one to monitor its children.
+        """
+        self.open()             # Ensure that self.claim is set
+
+        # We can only claim parallelism if there was a jobserver (i.e. a
+        # top-level "-jN" argument) and there were no other failures. Otherwise
+        # leave out the environment variable and let the child figure out what
+        # is best.
+        if self.claim:
+            os.environ["PARALLELISM"] = str(self.claim)
+
+        return subprocess.call(cmd, *args, **pwargs)
diff --git a/tools/lib/python/kdoc/__init__.py b/tools/lib/python/kdoc/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tools/lib/python/kdoc/__init__.py
diff --git a/tools/lib/python/kdoc/c_lex.py b/tools/lib/python/kdoc/c_lex.py
new file mode 100644
index 000000000..cb95f5172
--- /dev/null
+++ b/tools/lib/python/kdoc/c_lex.py
@@ -0,0 +1,662 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+
+"""
+Regular expression ancillary classes.
+
+Those help caching regular expressions and do matching for kernel-doc.
+
+Please notice that the code here may rise exceptions to indicate bad
+usage inside kdoc to indicate problems at the replace pattern.
+
+Other errors are logged via log instance.
+"""
+
+import logging
+import re
+
+from copy import copy
+
+from .kdoc_re import KernRe
+
+log = logging.getLogger(__name__)
+
+def tokenizer_set_log(logger, prefix = ""):
+    """
+    Replace the module‑level logger with a LoggerAdapter that
+    prepends *prefix* to every message.
+    """
+    global log
+
+    class PrefixAdapter(logging.LoggerAdapter):
+        """
+        Ancillary class to set prefix on all message logs.
+        """
+        def process(self, msg, kwargs):
+            return f"{prefix}{msg}", kwargs
+
+    # Wrap the provided logger in our adapter
+    log = PrefixAdapter(logger, {"prefix": prefix})
+
+class CToken():
+    """
+    Data class to define a C token.
+    """
+
+    # Tokens that can be used by the parser. Works like an C enum.
+
+    COMMENT = 0     #: A standard C or C99 comment, including delimiter.
+    STRING = 1      #: A string, including quotation marks.
+    CHAR = 2        #: A character, including apostophes.
+    NUMBER = 3      #: A number.
+    PUNC = 4        #: A puntuation mark: / ``,`` / ``.``.
+    BEGIN = 5       #: A begin character: ``{`` / ``[`` / ``(``.
+    END = 6         #: A end character: ``}`` / ``]`` / ``)``.
+    CPP = 7         #: A preprocessor macro.
+    HASH = 8        #: The hash character - useful to handle other macros.
+    OP = 9          #: A C operator (add, subtract, ...).
+    STRUCT = 10     #: A ``struct`` keyword.
+    UNION = 11      #: An ``union`` keyword.
+    ENUM = 12       #: A ``struct`` keyword.
+    TYPEDEF = 13    #: A ``typedef`` keyword.
+    NAME = 14       #: A name. Can be an ID or a type.
+    SPACE = 15      #: Any space characters, including new lines
+    ENDSTMT = 16    #: End of an statement (``;``).
+
+    BACKREF = 17    #: Not a valid C sequence, but used at sub regex patterns.
+
+    MISMATCH = 255  #: an error indicator: should never happen in practice.
+
+    # Dict to convert from an enum interger into a string.
+    _name_by_val = {v: k for k, v in dict(vars()).items() if isinstance(v, int)}
+
+    # Dict to convert from string to an enum-like integer value.
+    _name_to_val = {k: v for v, k in _name_by_val.items()}
+
+    @staticmethod
+    def to_name(val):
+        """Convert from an integer value from CToken enum into a string"""
+
+        return CToken._name_by_val.get(val, f"UNKNOWN({val})")
+
+    @staticmethod
+    def from_name(name):
+        """Convert a string into a CToken enum value"""
+        if name in CToken._name_to_val:
+            return CToken._name_to_val[name]
+
+        return CToken.MISMATCH
+
+
+    def __init__(self, kind, value=None, pos=0,
+                 brace_level=0, paren_level=0, bracket_level=0):
+        self.kind = kind
+        self.value = value
+        self.pos = pos
+        self.level = (bracket_level, paren_level, brace_level)
+
+    def __repr__(self):
+        name = self.to_name(self.kind)
+        if isinstance(self.value, str):
+            value = '"' + self.value + '"'
+        else:
+            value = self.value
+
+        return f"CToken(CToken.{name}, {value}, {self.pos}, {self.level})"
+
+#: Regexes to parse C code, transforming it into tokens.
+RE_SCANNER_LIST = [
+    #
+    # Note that \s\S is different than .*, as it also catches \n
+    #
+    (CToken.COMMENT, r"//[^\n]*|/\*[\s\S]*?\*/"),
+
+    (CToken.STRING,  r'"(?:\\.|[^"\\])*"'),
+    (CToken.CHAR,    r"'(?:\\.|[^'\\])'"),
+
+    (CToken.NUMBER,  r"0[xX][\da-fA-F]+[uUlL]*|0[0-7]+[uUlL]*|"
+                     r"\d+(?:\.\d*)?(?:[eE][+-]?\d+)?[fFlL]*"),
+
+    (CToken.ENDSTMT, r"(?:\s+;|;)"),
+
+    (CToken.PUNC,    r"[,\.]"),
+
+    (CToken.BEGIN,   r"[\[\(\{]"),
+
+    (CToken.END,     r"[\]\)\}]"),
+
+    (CToken.CPP,     r"#\s*(?:define|include|ifdef|ifndef|if|else|elif|endif|undef|pragma)\b"),
+
+    (CToken.HASH,    r"#"),
+
+    (CToken.OP,      r"\+\+|\-\-|\->|==|\!=|<=|>=|&&|\|\||<<|>>|\+=|\-=|\*=|/=|%="
+                     r"|&=|\|=|\^=|[=\+\-\*/%<>&\|\^~!\?\:]"),
+
+    (CToken.STRUCT,  r"\bstruct\b"),
+    (CToken.UNION,   r"\bunion\b"),
+    (CToken.ENUM,    r"\benum\b"),
+    (CToken.TYPEDEF, r"\btypedef\b"),
+
+    (CToken.NAME,    r"[A-Za-z_]\w*"),
+
+    (CToken.SPACE,   r"\s+"),
+
+    (CToken.BACKREF, r"\\\d+"),
+
+    (CToken.MISMATCH,r"."),
+]
+
+def fill_re_scanner(token_list):
+    """Ancillary routine to convert RE_SCANNER_LIST into a finditer regex"""
+    re_tokens = []
+
+    for kind, pattern in token_list:
+        name = CToken.to_name(kind)
+        re_tokens.append(f"(?P<{name}>{pattern})")
+
+    return KernRe("|".join(re_tokens), re.MULTILINE | re.DOTALL)
+
+#: Handle C continuation lines.
+RE_CONT = KernRe(r"\\\n")
+
+RE_COMMENT_START = KernRe(r'/\*\s*')
+
+#: tokenizer regex. Will be filled at the first CTokenizer usage.
+RE_SCANNER = fill_re_scanner(RE_SCANNER_LIST)
+
+
+class CTokenizer():
+    """
+    Scan C statements and definitions and produce tokens.
+
+    When converted to string, it drops comments and handle public/private
+    values, respecting depth.
+    """
+
+    # This class is inspired and follows the basic concepts of:
+    #   https://docs.python.org/3/library/re.html#writing-a-tokenizer
+
+    def __init__(self, source=None):
+        """
+        Create a regular expression to handle RE_SCANNER_LIST.
+
+        While I generally don't like using regex group naming via:
+            (?P<name>...)
+
+        in this particular case, it makes sense, as we can pick the name
+        when matching a code via RE_SCANNER.
+        """
+
+        #
+        # Store logger to allow parser classes to re-use it
+        #
+        global log
+        self.log = log
+
+        self.tokens = []
+
+        if not source:
+            return
+
+        if isinstance(source, list):
+            self.tokens = source
+            return
+
+        #
+        # While we could just use _tokenize directly via interator,
+        # As we'll need to use the tokenizer several times inside kernel-doc
+        # to handle macro transforms, cache the results on a list, as
+        # re-using it is cheaper than having to parse everytime.
+        #
+        for tok in self._tokenize(source):
+            self.tokens.append(tok)
+
+    def _tokenize(self, source):
+        """
+        Iterator that parses ``source``, splitting it into tokens, as defined
+        at ``self.RE_SCANNER_LIST``.
+
+        The interactor returns a CToken class object.
+        """
+
+        # Handle continuation lines. Note that kdoc_parser already has a
+        # logic to do that. Still, let's keep it for completeness, as we might
+        # end re-using this tokenizer outsize kernel-doc some day - or we may
+        # eventually remove from there as a future cleanup.
+        source = RE_CONT.sub("", source)
+
+        brace_level = 0
+        paren_level = 0
+        bracket_level = 0
+
+        for match in RE_SCANNER.finditer(source):
+            kind = CToken.from_name(match.lastgroup)
+            pos = match.start()
+            value = match.group()
+
+            if kind == CToken.MISMATCH:
+                log.error(f"Unexpected token '{value}' on pos {pos}:\n\t'{source}'")
+            elif kind == CToken.BEGIN:
+                if value == '(':
+                    paren_level += 1
+                elif value == '[':
+                    bracket_level += 1
+                else:  # value == '{'
+                    brace_level += 1
+
+            elif kind == CToken.END:
+                if value == ')' and paren_level > 0:
+                    paren_level -= 1
+                elif value == ']' and bracket_level > 0:
+                    bracket_level -= 1
+                elif brace_level > 0:    # value == '}'
+                    brace_level -= 1
+
+            yield CToken(kind, value, pos,
+                         brace_level, paren_level, bracket_level)
+
+    def __str__(self):
+        out=""
+        show_stack = [True]
+
+        for i, tok in enumerate(self.tokens):
+            if tok.kind == CToken.BEGIN:
+                show_stack.append(show_stack[-1])
+
+            elif tok.kind == CToken.END:
+                prev = show_stack[-1]
+                if len(show_stack) > 1:
+                    show_stack.pop()
+
+                if not prev and show_stack[-1]:
+                    #
+                    # Try to preserve indent
+                    #
+                    out += "\t" * (len(show_stack) - 1)
+
+                    out += str(tok.value)
+                    continue
+
+            elif tok.kind == CToken.COMMENT:
+                comment = RE_COMMENT_START.sub("", tok.value)
+
+                if comment.startswith("private:"):
+                    show_stack[-1] = False
+                    show = False
+                elif comment.startswith("public:"):
+                    show_stack[-1] = True
+
+                continue
+
+            if not show_stack[-1]:
+                continue
+
+            if i < len(self.tokens) - 1:
+                next_tok = self.tokens[i + 1]
+
+                # Do some cleanups before ";"
+
+                if tok.kind == CToken.SPACE and next_tok.kind == CToken.ENDSTMT:
+                    continue
+
+                if tok.kind == CToken.ENDSTMT and next_tok.kind == tok.kind:
+                    continue
+
+            out += str(tok.value)
+
+        return out
+
+
+class CTokenArgs:
+    """
+    Ancillary class to help using backrefs from sub matches.
+
+    If the highest backref contain a "+" at the last element,
+    the logic will be greedy, picking all other delims.
+
+    This is needed to parse struct_group macros with end with ``MEMBERS...``.
+    """
+    def __init__(self, sub_str):
+        self.sub_groups = set()
+        self.max_group = -1
+        self.greedy = None
+
+        for m in KernRe(r'\\(\d+)([+]?)').finditer(sub_str):
+            group = int(m.group(1))
+            if m.group(2) == "+":
+                if self.greedy and self.greedy != group:
+                    raise ValueError("There are multiple greedy patterns!")
+                self.greedy = group
+
+            self.sub_groups.add(group)
+            self.max_group = max(self.max_group, group)
+
+        if self.greedy:
+            if self.greedy != self.max_group:
+                raise ValueError("Greedy pattern is not the last one!")
+
+            sub_str = KernRe(r'(\\\d+)[+]').sub(r"\1", sub_str)
+
+        self.sub_str = sub_str
+        self.sub_tokeninzer = CTokenizer(sub_str)
+
+    def groups(self, new_tokenizer):
+        r"""
+        Create replacement arguments for backrefs like:
+
+        ``\0``, ``\1``, ``\2``, ... ``\{number}``
+
+        It also accepts a ``+`` character to the highest backref, like
+        ``\4+``. When used, the backref will be greedy, picking all other
+        arguments afterwards.
+
+        The logic is smart enough to only go up to the maximum required
+        argument, even if there are more.
+
+        If there is a backref for an argument above the limit, it will
+        raise an exception. Please notice that, on C, square brackets
+        don't have any separator on it. Trying to use ``\1``..``\n`` for
+        brackets also raise an exception.
+        """
+
+        level = (0, 0, 0)
+
+        if self.max_group < 0:
+            return level, []
+
+        tokens = new_tokenizer.tokens
+
+        #
+        # Fill \0 with the full token contents
+        #
+        groups_list = [ [] ]
+
+        if 0 in self.sub_groups:
+            inner_level = 0
+
+            for i in range(0, len(tokens)):
+                tok = tokens[i]
+
+                if tok.kind == CToken.BEGIN:
+                    inner_level += 1
+
+                    #
+                    # Discard first begin
+                    #
+                    if not groups_list[0]:
+                        continue
+                elif tok.kind == CToken.END:
+                    inner_level -= 1
+                    if inner_level < 0:
+                        break
+
+                if inner_level:
+                    groups_list[0].append(tok)
+
+        if not self.max_group:
+            return level, groups_list
+
+        delim = None
+
+        #
+        # Ignore everything before BEGIN. The value of begin gives the
+        # delimiter to be used for the matches
+        #
+        for i in range(0, len(tokens)):
+            tok = tokens[i]
+            if tok.kind == CToken.BEGIN:
+                if tok.value == "{":
+                    delim = ";"
+                elif tok.value == "(":
+                    delim = ","
+                else:
+                    self.log.error(fr"Can't handle \1..\n on {sub_str}")
+
+                level = tok.level
+                break
+
+        pos = 1
+        groups_list.append([])
+
+        inner_level = 0
+        for i in range(i + 1, len(tokens)):
+            tok = tokens[i]
+
+            if tok.kind == CToken.BEGIN:
+                inner_level += 1
+            if tok.kind == CToken.END:
+                inner_level -= 1
+                if inner_level < 0:
+                    break
+
+            if tok.kind in [CToken.PUNC, CToken.ENDSTMT] and delim == tok.value:
+                pos += 1
+                if self.greedy and pos > self.max_group:
+                    pos -= 1
+                else:
+                    groups_list.append([])
+
+                    if pos > self.max_group:
+                        break
+
+                    continue
+
+            groups_list[pos].append(tok)
+
+        if pos < self.max_group:
+            log.error(fr"{self.sub_str} groups are up to {pos} instead of {self.max_group}")
+
+        return level, groups_list
+
+    def tokens(self, new_tokenizer):
+        level, groups = self.groups(new_tokenizer)
+
+        new = CTokenizer()
+
+        for tok in self.sub_tokeninzer.tokens:
+            if tok.kind == CToken.BACKREF:
+                group = int(tok.value[1:])
+
+                for group_tok in groups[group]:
+                    new_tok = copy(group_tok)
+
+                    new_level = [0, 0, 0]
+
+                    for i in range(0, len(level)):
+                        new_level[i] = new_tok.level[i] + level[i]
+
+                    new_tok.level = tuple(new_level)
+
+                    new.tokens += [ new_tok ]
+            else:
+                new.tokens += [ tok ]
+
+        return new.tokens
+
+
+class CMatch:
+    """
+    Finding nested delimiters is hard with regular expressions. It is
+    even harder on Python with its normal re module, as there are several
+    advanced regular expressions that are missing.
+
+    This is the case of this pattern::
+
+            '\\bSTRUCT_GROUP(\\(((?:(?>[^)(]+)|(?1))*)\\))[^;]*;'
+
+    which is used to properly match open/close parentheses of the
+    string search STRUCT_GROUP(),
+
+    Add a class that counts pairs of delimiters, using it to match and
+    replace nested expressions.
+
+    The original approach was suggested by:
+
+        https://stackoverflow.com/questions/5454322/python-how-to-match-nested-parentheses-with-regex
+
+    Although I re-implemented it to make it more generic and match 3 types
+    of delimiters. The logic checks if delimiters are paired. If not, it
+    will ignore the search string.
+    """
+
+
+    def __init__(self, regex, delim="("):
+        self.regex = KernRe("^" + regex + r"\b")
+        self.start_delim = delim
+
+    def _search(self, tokenizer):
+        """
+        Finds paired blocks for a regex that ends with a delimiter.
+
+        The suggestion of using finditer to match pairs came from:
+        https://stackoverflow.com/questions/5454322/python-how-to-match-nested-parentheses-with-regex
+        but I ended using a different implementation to align all three types
+        of delimiters and seek for an initial regular expression.
+
+        The algorithm seeks for open/close paired delimiters and places them
+        into a stack, yielding a start/stop position of each match when the
+        stack is zeroed.
+
+        The algorithm should work fine for properly paired lines, but will
+        silently ignore end delimiters that precede a start delimiter.
+        This should be OK for kernel-doc parser, as unaligned delimiters
+        would cause compilation errors. So, we don't need to raise exceptions
+        to cover such issues.
+        """
+
+        start = None
+        started = False
+
+        import sys
+
+        stack = []
+
+        for i, tok in enumerate(tokenizer.tokens):
+            if start is None:
+                if tok.kind == CToken.NAME and self.regex.match(tok.value):
+                    start = i
+                    stack.append((start, tok.level))
+                    started = False
+
+                continue
+
+            if not started:
+                if tok.kind == CToken.SPACE:
+                    continue
+
+                if tok.kind == CToken.BEGIN and tok.value == self.start_delim:
+                    started = True
+                    continue
+
+                # Name only token without BEGIN/END
+                if i > start:
+                    i -= 1
+                yield start, i
+                start = None
+
+            if tok.kind == CToken.END and tok.level == stack[-1][1]:
+                start, level = stack.pop()
+
+                yield start, i
+                start = None
+
+        #
+        # If an END zeroing levels is not there, return remaining stuff
+        # This is meant to solve cases where the caller logic might be
+        # picking an incomplete block.
+        #
+        if start and stack:
+            if started:
+                s = str(tokenizer)
+                log.warning(f"can't find a final end at {s}")
+
+            yield start, len(tokenizer.tokens)
+
+    def search(self, source):
+        """
+        This is similar to re.search:
+
+        It matches a regex that it is followed by a delimiter,
+        returning occurrences only if all delimiters are paired.
+        """
+
+        if isinstance(source, CTokenizer):
+            tokenizer = source
+            is_token = True
+        else:
+            tokenizer = CTokenizer(source)
+            is_token = False
+
+        for start, end in self._search(tokenizer):
+            new_tokenizer = CTokenizer(tokenizer.tokens[start:end + 1])
+
+            if is_token:
+                yield new_tokenizer
+            else:
+                yield str(new_tokenizer)
+
+    def sub(self, sub_str, source, count=0):
+        """
+        This is similar to re.sub:
+
+        It matches a regex that it is followed by a delimiter,
+        replacing occurrences only if all delimiters are paired.
+
+        if the sub argument contains::
+
+            r'\0'
+
+        it will work just like re: it places there the matched paired data
+        with the delimiter stripped.
+
+        If count is different than zero, it will replace at most count
+        items.
+        """
+        if isinstance(source, CTokenizer):
+            is_token = True
+            tokenizer = source
+        else:
+            is_token = False
+            tokenizer = CTokenizer(source)
+
+        # Detect if sub_str contains sub arguments
+
+        args_match = CTokenArgs(sub_str)
+
+        new_tokenizer = CTokenizer()
+        pos = 0
+        n = 0
+
+        #
+        # NOTE: the code below doesn't consider overlays at sub.
+        # We may need to add some extra unit tests to check if those
+        # would cause problems. When replacing by "", this should not
+        # be a problem, but other transformations could be problematic
+        #
+        for start, end in self._search(tokenizer):
+            new_tokenizer.tokens += tokenizer.tokens[pos:start]
+
+            new = CTokenizer(tokenizer.tokens[start:end + 1])
+
+            new_tokenizer.tokens += args_match.tokens(new)
+
+            pos = end + 1
+
+            n += 1
+            if count and n >= count:
+                break
+
+        new_tokenizer.tokens += tokenizer.tokens[pos:]
+
+        if not is_token:
+            return str(new_tokenizer)
+
+        return new_tokenizer
+
+    def __repr__(self):
+        """
+        Returns a displayable version of the class init.
+        """
+
+        return f'CMatch("{self.regex.regex.pattern}")'
diff --git a/tools/lib/python/kdoc/enrich_formatter.py b/tools/lib/python/kdoc/enrich_formatter.py
new file mode 100644
index 000000000..d1be4e5e1
--- /dev/null
+++ b/tools/lib/python/kdoc/enrich_formatter.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2025 by Mauro Carvalho Chehab <mchehab@kernel.org>.
+
+"""
+Ancillary argparse HelpFormatter class that works on a similar way as
+argparse.RawDescriptionHelpFormatter, e.g. description maintains line
+breaks, but it also implement transformations to the help text. The
+actual transformations ar given by enrich_text(), if the output is tty.
+
+Currently, the follow transformations are done:
+
+    - Positional arguments are shown in upper cases;
+    - if output is TTY, ``var`` and positional arguments are shown prepended
+      by an ANSI SGR code. This is usually translated to bold. On some
+      terminals, like, konsole, this is translated into a colored bold text.
+"""
+
+import argparse
+import re
+import sys
+
+class EnrichFormatter(argparse.HelpFormatter):
+    """
+    Better format the output, making easier to identify the positional args
+    and how they're used at the __doc__ description.
+    """
+    def __init__(self, *args, **kwargs):
+        """
+        Initialize class and check if is TTY.
+        """
+        super().__init__(*args, **kwargs)
+        self._tty = sys.stdout.isatty()
+
+    def enrich_text(self, text):
+        r"""
+        Handle ReST markups (currently, only \`\`text\`\` markups).
+        """
+        if self._tty and text:
+            # Replace ``text`` with ANSI SGR (bold)
+            return re.sub(r'\`\`(.+?)\`\`',
+                          lambda m: f'\033[1m{m.group(1)}\033[0m', text)
+        return text
+
+    def _fill_text(self, text, width, indent):
+        """
+        Enrich descriptions with markups on it.
+        """
+        enriched = self.enrich_text(text)
+        return "\n".join(indent + line for line in enriched.splitlines())
+
+    def _format_usage(self, usage, actions, groups, prefix):
+        """
+        Enrich positional arguments at usage: line.
+        """
+
+        prog = self._prog
+        parts = []
+
+        for action in actions:
+            if action.option_strings:
+                opt = action.option_strings[0]
+                if action.nargs != 0:
+                    opt += f" {action.dest.upper()}"
+                parts.append(f"[{opt}]")
+            else:
+                # Positional argument
+                parts.append(self.enrich_text(f"``{action.dest.upper()}``"))
+
+        usage_text = f"{prefix or 'usage: '} {prog} {' '.join(parts)}\n"
+        return usage_text
+
+    def _format_action_invocation(self, action):
+        """
+        Enrich argument names.
+        """
+        if not action.option_strings:
+            return self.enrich_text(f"``{action.dest.upper()}``")
+
+        return ", ".join(action.option_strings)
diff --git a/tools/lib/python/kdoc/kdoc_files.py b/tools/lib/python/kdoc/kdoc_files.py
new file mode 100644
index 000000000..ed82b6e6a
--- /dev/null
+++ b/tools/lib/python/kdoc/kdoc_files.py
@@ -0,0 +1,380 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+#
+# pylint: disable=R0903,R0913,R0914,R0917
+
+"""
+Classes for navigating through the files that kernel-doc needs to handle
+to generate documentation.
+"""
+
+import logging
+import os
+import re
+
+from kdoc.kdoc_parser import KernelDoc
+from kdoc.xforms_lists import CTransforms
+from kdoc.kdoc_output import OutputFormat
+from kdoc.kdoc_yaml_file import KDocTestFile
+
+
+class GlobSourceFiles:
+    """
+    Parse C source code file names and directories via an Interactor.
+    """
+
+    def __init__(self, srctree=None, valid_extensions=None):
+        """
+        Initialize valid extensions with a tuple.
+
+        If not defined, assume default C extensions (.c and .h)
+
+        It would be possible to use python's glob function, but it is
+        very slow, and it is not interactive. So, it would wait to read all
+        directories before actually do something.
+
+        So, let's use our own implementation.
+        """
+
+        if not valid_extensions:
+            self.extensions = (".c", ".h")
+        else:
+            self.extensions = valid_extensions
+
+        self.srctree = srctree
+
+    def _parse_dir(self, dirname):
+        """Internal function to parse files recursively."""
+
+        with os.scandir(dirname) as obj:
+            for entry in obj:
+                name = os.path.join(dirname, entry.name)
+
+                if entry.is_dir(follow_symlinks=False):
+                    yield from self._parse_dir(name)
+
+                if not entry.is_file():
+                    continue
+
+                basename = os.path.basename(name)
+
+                if not basename.endswith(self.extensions):
+                    continue
+
+                yield name
+
+    def parse_files(self, file_list, file_not_found_cb):
+        """
+        Define an iterator to parse all source files from file_list,
+        handling directories if any.
+        """
+
+        if not file_list:
+            return
+
+        for fname in file_list:
+            if self.srctree:
+                f = os.path.join(self.srctree, fname)
+            else:
+                f = fname
+
+            if os.path.isdir(f):
+                yield from self._parse_dir(f)
+            elif os.path.isfile(f):
+                yield f
+            elif file_not_found_cb:
+                file_not_found_cb(fname)
+
+
+class KdocConfig():
+    """
+    Stores all configuration attributes that kdoc_parser and kdoc_output
+    needs.
+    """
+    def __init__(self, verbose=False, werror=False, wreturn=False,
+                 wshort_desc=False, wcontents_before_sections=False,
+                 logger=None):
+
+        self.verbose = verbose
+        self.werror = werror
+        self.wreturn = wreturn
+        self.wshort_desc =  wshort_desc
+        self.wcontents_before_sections = wcontents_before_sections
+
+        if logger:
+            self.log = logger
+        else:
+            self.log = logging.getLogger(__file__)
+
+        self.warning = self.log.warning
+
+class KernelFiles():
+    """
+    Parse kernel-doc tags on multiple kernel source files.
+
+    This is the main entry point to run kernel-doc. This class is initialized
+    using a series of optional arguments:
+
+    ``verbose``
+        If True, enables kernel-doc verbosity. Default: False.
+
+    ``out_style``
+        Class to be used to format output. If None (default),
+        only report errors.
+
+    ``xforms``
+        Transforms to be applied to C prototypes and data structs.
+        If not specified, defaults to xforms = CFunction()
+
+    ``werror``
+        If True, treat warnings as errors, retuning an error code on warnings.
+
+        Default: False.
+
+    ``wreturn``
+        If True, warns about the lack of a return markup on functions.
+
+        Default: False.
+    ``wshort_desc``
+        If True, warns if initial short description is missing.
+
+        Default: False.
+
+    ``wcontents_before_sections``
+        If True, warn if there are contents before sections (deprecated).
+        This option is kept just for backward-compatibility, but it does
+        nothing, neither here nor at the original Perl script.
+
+        Default: False.
+
+    ``logger``
+        Optional logger class instance.
+
+        If not specified, defaults to use: ``logging.getLogger("kernel-doc")``
+
+    ``yaml_file``
+        If defined, stores the output inside a YAML file.
+
+    ``yaml_content``
+        Defines what will be inside the YAML file.
+
+    Note:
+        There are two type of parsers defined here:
+
+        - self.parse_file(): parses both kernel-doc markups and
+          ``EXPORT_SYMBOL*`` macros;
+        - self.process_export_file(): parses only ``EXPORT_SYMBOL*`` macros.
+    """
+
+    def warning(self, msg):
+        """Ancillary routine to output a warning and increment error count."""
+
+        self.config.log.warning(msg)
+        self.errors += 1
+
+    def error(self, msg):
+        """Ancillary routine to output an error and increment error count."""
+
+        self.config.log.error(msg)
+        self.errors += 1
+
+    def parse_file(self, fname):
+        """
+        Parse a single Kernel source.
+        """
+
+        # Prevent parsing the same file twice if results are cached
+        if fname in self.files:
+            return
+
+        if self.test_file:
+            store_src = True
+        else:
+            store_src = False
+
+        doc = KernelDoc(self.config, fname, self.xforms, store_src=store_src)
+        export_table, entries = doc.parse_kdoc()
+
+        self.export_table[fname] = export_table
+
+        self.files.add(fname)
+        self.export_files.add(fname)      # parse_kdoc() already check exports
+
+        self.results[fname] = entries
+
+    def process_export_file(self, fname):
+        """
+        Parses ``EXPORT_SYMBOL*`` macros from a single Kernel source file.
+        """
+
+        # Prevent parsing the same file twice if results are cached
+        if fname in self.export_files:
+            return
+
+        doc = KernelDoc(self.config, fname)
+        export_table = doc.parse_export()
+
+        if not export_table:
+            self.error(f"Error: Cannot check EXPORT_SYMBOL* on {fname}")
+            export_table = set()
+
+        self.export_table[fname] = export_table
+        self.export_files.add(fname)
+
+    def file_not_found_cb(self, fname):
+        """
+        Callback to warn if a file was not found.
+        """
+
+        self.error(f"Cannot find file {fname}")
+
+    def __init__(self, verbose=False, out_style=None, xforms=None,
+                 werror=False, wreturn=False, wshort_desc=False,
+                 wcontents_before_sections=False,
+                 yaml_file=None, yaml_content=None, logger=None):
+        """
+        Initialize startup variables and parse all files.
+        """
+
+        if not verbose:
+            try:
+                verbose = bool(int(os.environ.get("KBUILD_VERBOSE", 0)))
+            except ValueError:
+                # Handles an eventual case where verbosity is not a number
+                # like KBUILD_VERBOSE=""
+                verbose = False
+
+        if out_style is None:
+            out_style = OutputFormat()
+
+        if not werror:
+            kcflags = os.environ.get("KCFLAGS", None)
+            if kcflags:
+                match = re.search(r"(\s|^)-Werror(\s|$)/", kcflags)
+                if match:
+                    werror = True
+
+            # reading this variable is for backwards compat just in case
+            # someone was calling it with the variable from outside the
+            # kernel's build system
+            kdoc_werror = os.environ.get("KDOC_WERROR", None)
+            if kdoc_werror:
+                werror = kdoc_werror
+
+        if not logger:
+           logger = logging.getLogger("kernel-doc")
+        else:
+            logger = logger
+
+        # Some variables are global to the parser logic as a whole as they are
+        # used to send control configuration to KernelDoc class. As such,
+        # those variables are read-only inside the KernelDoc.
+        self.config = KdocConfig(verbose, werror, wreturn, wshort_desc,
+                                 wcontents_before_sections, logger)
+
+        # Override log warning, as we want to count errors
+        self.config.warning = self.warning
+
+        if yaml_file:
+            self.test_file = KDocTestFile(self.config, yaml_file, yaml_content)
+        else:
+            self.test_file = None
+
+        if xforms:
+            self.xforms = xforms
+        else:
+            self.xforms = CTransforms()
+
+        self.config.src_tree = os.environ.get("SRCTREE", None)
+
+        # Initialize variables that are internal to KernelFiles
+
+        self.out_style = out_style
+        self.out_style.set_config(self.config)
+
+        self.errors = 0
+        self.results = {}
+
+        self.files = set()
+        self.export_files = set()
+        self.export_table = {}
+
+    def parse(self, file_list, export_file=None):
+        """
+        Parse all files.
+        """
+
+        glob = GlobSourceFiles(srctree=self.config.src_tree)
+
+        for fname in glob.parse_files(file_list, self.file_not_found_cb):
+            self.parse_file(fname)
+
+        for fname in glob.parse_files(export_file, self.file_not_found_cb):
+            self.process_export_file(fname)
+
+    def out_msg(self, fname, name, arg):
+        """
+        Return output messages from a file name using the output style
+        filtering.
+
+        If output type was not handled by the styler, return None.
+        """
+
+        # NOTE: we can add rules here to filter out unwanted parts,
+        # although OutputFormat.msg already does that.
+
+        return self.out_style.msg(fname, name, arg)
+
+    def msg(self, enable_lineno=False, export=False, internal=False,
+            symbol=None, nosymbol=None, no_doc_sections=False,
+            filenames=None, export_file=None):
+        """
+        Interacts over the kernel-doc results and output messages,
+        returning kernel-doc markups on each interaction.
+        """
+
+        if not filenames:
+            filenames = sorted(self.results.keys())
+
+        glob = GlobSourceFiles(srctree=self.config.src_tree)
+
+        for fname in filenames:
+            function_table = set()
+
+            if internal or export:
+                if not export_file:
+                    export_file = [fname]
+
+                for f in glob.parse_files(export_file, self.file_not_found_cb):
+                    function_table |= self.export_table[f]
+
+            if symbol:
+                for s in symbol:
+                    function_table.add(s)
+
+            if fname not in self.results:
+                self.config.log.warning("No kernel-doc for file %s", fname)
+                continue
+
+            symbols = self.results[fname]
+
+            if self.test_file:
+                self.test_file.set_filter(export, internal, symbol, nosymbol,
+                                          function_table, enable_lineno,
+                                          no_doc_sections)
+
+                self.test_file.output_symbols(fname, symbols)
+
+                continue
+
+            self.out_style.set_filter(export, internal, symbol, nosymbol,
+                                      function_table, enable_lineno,
+                                      no_doc_sections)
+
+            msg = self.out_style.output_symbols(fname, symbols)
+            if msg:
+                yield fname, msg
+
+        if self.test_file:
+            self.test_file.write()
diff --git a/tools/lib/python/kdoc/kdoc_item.py b/tools/lib/python/kdoc/kdoc_item.py
new file mode 100644
index 000000000..a7aa6e1e4
--- /dev/null
+++ b/tools/lib/python/kdoc/kdoc_item.py
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# A class that will, eventually, encapsulate all of the parsed data that we
+# then pass into the output modules.
+#
+
+"""
+Data class to store a kernel-doc Item.
+"""
+
+class KdocItem:
+    """
+    A class that will, eventually, encapsulate all of the parsed data that we
+    then pass into the output modules.
+    """
+
+    def __init__(self, name, fname, type, start_line,
+                 **other_stuff):
+        self.name = name
+        self.fname = fname
+        self.type = type
+        self.declaration_start_line = start_line
+        self.sections = {}
+        self.sections_start_lines = {}
+        self.parameterlist = []
+        self.parameterdesc_start_lines = {}
+        self.parameterdescs = {}
+        self.parametertypes = {}
+
+        self.warnings = []
+
+        #
+        # Just save everything else into our own dict so that the output
+        # side can grab it directly as before.  As we move things into more
+        # structured data, this will, hopefully, fade away.
+        #
+        known_keys = {
+            'declaration_start_line',
+            'sections',
+            'sections_start_lines',
+            'parameterlist',
+            'parameterdesc_start_lines',
+            'parameterdescs',
+            'parametertypes',
+            'warnings',
+        }
+
+        self.other_stuff = {}
+        for k, v in other_stuff.items():
+            if k in known_keys:
+                setattr(self, k, v)           # real attribute
+            else:
+                self.other_stuff[k] = v
+
+    def get(self, key, default = None):
+        """
+        Get a value from optional keys.
+        """
+        return self.other_stuff.get(key, default)
+
+    def __getitem__(self, key):
+        return self.get(key)
+
+    def __repr__(self):
+        return f"KdocItem({self.name}, {self.fname}, {self.type}, {self.declaration_start_line})"
+
+    @classmethod
+    def from_dict(cls, d):
+        """Create a KdocItem from a plain dict."""
+
+        cp = d.copy()
+        name        = cp.pop('name', None)
+        fname       = cp.pop('fname', None)
+        type        = cp.pop('type', None)
+        start_line  = cp.pop('start_line', 1)
+        other_stuff = cp.pop('other_stuff', {})
+
+        # Everything that’s left goes straight to __init__
+        return cls(name, fname, type, start_line, **cp, **other_stuff)
+
+    #
+    # Tracking of section and parameter information.
+    #
+    def set_sections(self, sections, start_lines):
+        """
+        Set sections and start lines.
+        """
+        self.sections = sections
+        self.sections_start_lines = start_lines
+
+    def set_params(self, names, descs, types, starts):
+        """
+        Set parameter list: names, descriptions, types and start lines.
+        """
+        self.parameterlist = names
+        self.parameterdescs = descs
+        self.parametertypes = types
+        self.parameterdesc_start_lines = starts
diff --git a/tools/lib/python/kdoc/kdoc_output.py b/tools/lib/python/kdoc/kdoc_output.py
new file mode 100644
index 000000000..618b0d765
--- /dev/null
+++ b/tools/lib/python/kdoc/kdoc_output.py
@@ -0,0 +1,1160 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+#
+# pylint: disable=C0301,R0902,R0911,R0912,R0913,R0914,R0915,R0917
+
+"""
+Classes to implement output filters to print kernel-doc documentation.
+
+The implementation uses a virtual base class ``OutputFormat``. It
+contains dispatches to virtual methods, and some code to filter
+out output messages.
+
+The actual implementation is done on one separate class per each type
+of output, e.g. ``RestFormat`` and ``ManFormat`` classes.
+
+Currently, there are output classes for ReST and man/troff.
+"""
+
+import os
+import re
+from datetime import datetime
+
+from kdoc.kdoc_parser import KernelDoc, type_param
+from kdoc.kdoc_re import KernRe
+
+
+function_pointer = KernRe(r"([^\(]*\(\*)\s*\)\s*\(([^\)]*)\)", cache=False)
+
+# match expressions used to find embedded type information
+type_constant = KernRe(r"\b``([^\`]+)``\b", cache=False)
+type_constant2 = KernRe(r"\%([-_*\w]+)", cache=False)
+type_func = KernRe(r"(\w+)\(\)", cache=False)
+type_param_ref = KernRe(r"([\!~\*]?)\@(\w*((\.\w+)|(->\w+))*(\.\.\.)?)", cache=False)
+
+# Special RST handling for func ptr params
+type_fp_param = KernRe(r"\@(\w+)\(\)", cache=False)
+
+# Special RST handling for structs with func ptr params
+type_fp_param2 = KernRe(r"\@(\w+->\S+)\(\)", cache=False)
+
+type_env = KernRe(r"(\$\w+)", cache=False)
+type_enum = KernRe(r"\&(enum\s*([_\w]+))", cache=False)
+type_struct = KernRe(r"\&(struct\s*([_\w]+))", cache=False)
+type_typedef = KernRe(r"\&(typedef\s*([_\w]+))", cache=False)
+type_union = KernRe(r"\&(union\s*([_\w]+))", cache=False)
+type_member = KernRe(r"\&([_\w]+)(\.|->)([_\w]+)", cache=False)
+type_fallback = KernRe(r"\&([_\w]+)", cache=False)
+type_member_func = type_member + KernRe(r"\(\)", cache=False)
+
+
+class OutputFormat:
+    """
+    Base class for OutputFormat. If used as-is, it means that only
+    warnings will be displayed.
+    """
+
+    # output mode.
+    OUTPUT_ALL          = 0 #: Output all symbols and doc sections.
+    OUTPUT_INCLUDE      = 1 #: Output only specified symbols.
+    OUTPUT_EXPORTED     = 2 #: Output exported symbols.
+    OUTPUT_INTERNAL     = 3 #: Output non-exported symbols.
+
+    #: Highlights to be used in ReST format.
+    highlights = []
+
+    #: Blank line character.
+    blankline = ""
+
+    def __init__(self):
+        """Declare internal vars and set mode to ``OUTPUT_ALL``."""
+
+        self.out_mode = self.OUTPUT_ALL
+        self.enable_lineno = None
+        self.nosymbol = {}
+        self.symbol = None
+        self.function_table = None
+        self.config = None
+        self.no_doc_sections = False
+
+        self.data = ""
+
+    def set_config(self, config):
+        """
+        Setup global config variables used by both parser and output.
+        """
+
+        self.config = config
+
+    def set_filter(self, export, internal, symbol, nosymbol, function_table,
+                   enable_lineno, no_doc_sections):
+        """
+        Initialize filter variables according to the requested mode.
+
+        Only one choice is valid between export, internal and symbol.
+
+        The nosymbol filter can be used on all modes.
+        """
+
+        self.enable_lineno = enable_lineno
+        self.no_doc_sections = no_doc_sections
+        self.function_table = function_table
+
+        if symbol:
+            self.out_mode = self.OUTPUT_INCLUDE
+        elif export:
+            self.out_mode = self.OUTPUT_EXPORTED
+        elif internal:
+            self.out_mode = self.OUTPUT_INTERNAL
+        else:
+            self.out_mode = self.OUTPUT_ALL
+
+        if nosymbol:
+            self.nosymbol = set(nosymbol)
+
+
+    def highlight_block(self, block):
+        """
+        Apply the RST highlights to a sub-block of text.
+        """
+
+        for r, sub in self.highlights:
+            block = r.sub(sub, block)
+
+        return block
+
+    def out_warnings(self, args):
+        """
+        Output warnings for identifiers that will be displayed.
+        """
+
+        for log_msg in args.warnings:
+            self.config.warning(log_msg)
+
+    def check_doc(self, name, args):
+        """Check if DOC should be output."""
+
+        if self.no_doc_sections:
+            return False
+
+        if name in self.nosymbol:
+            return False
+
+        if self.out_mode == self.OUTPUT_ALL:
+            self.out_warnings(args)
+            return True
+
+        if self.out_mode == self.OUTPUT_INCLUDE:
+            if name in self.function_table:
+                self.out_warnings(args)
+                return True
+
+        return False
+
+    def check_declaration(self, dtype, name, args):
+        """
+        Checks if a declaration should be output or not based on the
+        filtering criteria.
+        """
+
+        if name in self.nosymbol:
+            return False
+
+        if self.out_mode == self.OUTPUT_ALL:
+            self.out_warnings(args)
+            return True
+
+        if self.out_mode in [self.OUTPUT_INCLUDE, self.OUTPUT_EXPORTED]:
+            if name in self.function_table:
+                return True
+
+        if self.out_mode == self.OUTPUT_INTERNAL:
+            if dtype != "function":
+                self.out_warnings(args)
+                return True
+
+            if name not in self.function_table:
+                self.out_warnings(args)
+                return True
+
+        return False
+
+    def msg(self, fname, name, args):
+        """
+        Handles a single entry from kernel-doc parser.
+        """
+
+        self.data = ""
+
+        dtype = args.type
+
+        if dtype == "doc":
+            self.out_doc(fname, name, args)
+            return self.data
+
+        if not self.check_declaration(dtype, name, args):
+            return self.data
+
+        if dtype == "function":
+            self.out_function(fname, name, args)
+            return self.data
+
+        if dtype == "enum":
+            self.out_enum(fname, name, args)
+            return self.data
+
+        if dtype == "var":
+            self.out_var(fname, name, args)
+            return self.data
+
+        if dtype == "typedef":
+            self.out_typedef(fname, name, args)
+            return self.data
+
+        if dtype in ["struct", "union"]:
+            self.out_struct(fname, name, args)
+            return self.data
+
+        # Warn if some type requires an output logic
+        self.config.log.warning("doesn't know how to output '%s' block",
+                                dtype)
+
+        return None
+
+    def output_symbols(self, fname, symbols):
+        """
+        Handles a set of KdocItem symbols.
+        """
+        self.set_symbols(symbols)
+
+        msg = ""
+        for arg in symbols:
+            m = self.msg(fname, arg.name, arg)
+
+            if m is None:
+                ln = arg.get("ln", 0)
+                dtype = arg.get('type', "")
+
+                self.config.log.warning("%s:%d Can't handle %s",
+                                        fname, ln, dtype)
+            else:
+                msg += m
+
+        return msg
+
+    # Virtual methods to be overridden by inherited classes
+    # At the base class, those do nothing.
+    def set_symbols(self, symbols):
+        """Get a list of all symbols from kernel_doc."""
+
+    def out_doc(self, fname, name, args):
+        """Outputs a DOC block."""
+
+    def out_function(self, fname, name, args):
+        """Outputs a function."""
+
+    def out_enum(self, fname, name, args):
+        """Outputs an enum."""
+
+    def out_var(self, fname, name, args):
+        """Outputs a variable."""
+
+    def out_typedef(self, fname, name, args):
+        """Outputs a typedef."""
+
+    def out_struct(self, fname, name, args):
+        """Outputs a struct."""
+
+
+class RestFormat(OutputFormat):
+    """Consts and functions used by ReST output."""
+
+    #: Highlights to be used in ReST format
+    highlights = [
+        (type_constant, r"``\1``"),
+        (type_constant2, r"``\1``"),
+
+        # Note: need to escape () to avoid func matching later
+        (type_member_func, r":c:type:`\1\2\3\\(\\) <\1>`"),
+        (type_member, r":c:type:`\1\2\3 <\1>`"),
+        (type_fp_param, r"**\1\\(\\)**"),
+        (type_fp_param2, r"**\1\\(\\)**"),
+        (type_func, r"\1()"),
+        (type_enum, r":c:type:`\1 <\2>`"),
+        (type_struct, r":c:type:`\1 <\2>`"),
+        (type_typedef, r":c:type:`\1 <\2>`"),
+        (type_union, r":c:type:`\1 <\2>`"),
+
+        # in rst this can refer to any type
+        (type_fallback, r":c:type:`\1`"),
+        (type_param_ref, r"**\1\2**")
+    ]
+
+    blankline = "\n"
+
+    #: Sphinx literal block regex.
+    sphinx_literal = KernRe(r'^[^.].*::$', cache=False)
+
+    #: Sphinx code block regex.
+    sphinx_cblock = KernRe(r'^\.\.\ +code-block::', cache=False)
+
+    def __init__(self):
+        """
+        Creates class variables.
+
+        Not really mandatory, but it is a good coding style and makes
+        pylint happy.
+        """
+
+        super().__init__()
+        self.lineprefix = ""
+
+    def print_lineno(self, ln):
+        """Outputs a line number."""
+
+        if self.enable_lineno and ln is not None:
+            ln += 1
+            self.data += f".. LINENO {ln}\n"
+
+    def output_highlight(self, args):
+        """
+        Outputs a C symbol that may require being converted to ReST using
+        the self.highlights variable.
+        """
+
+        input_text = args
+        output = ""
+        in_literal = False
+        litprefix = ""
+        block = ""
+
+        for line in input_text.strip("\n").split("\n"):
+
+            # If we're in a literal block, see if we should drop out of it.
+            # Otherwise, pass the line straight through unmunged.
+            if in_literal:
+                if line.strip():  # If the line is not blank
+                    # If this is the first non-blank line in a literal block,
+                    # figure out the proper indent.
+                    if not litprefix:
+                        r = KernRe(r'^(\s*)')
+                        if r.match(line):
+                            litprefix = '^' + r.group(1)
+                        else:
+                            litprefix = ""
+
+                        output += line + "\n"
+                    elif not KernRe(litprefix).match(line):
+                        in_literal = False
+                    else:
+                        output += line + "\n"
+                else:
+                    output += line + "\n"
+
+            # Not in a literal block (or just dropped out)
+            if not in_literal:
+                block += line + "\n"
+                if self.sphinx_literal.match(line) or self.sphinx_cblock.match(line):
+                    in_literal = True
+                    litprefix = ""
+                    output += self.highlight_block(block)
+                    block = ""
+
+        # Handle any remaining block
+        if block:
+            output += self.highlight_block(block)
+
+        # Print the output with the line prefix
+        for line in output.strip("\n").split("\n"):
+            self.data += self.lineprefix + line + "\n"
+
+    def out_section(self, args, out_docblock=False):
+        """
+        Outputs a block section.
+
+        This could use some work; it's used to output the DOC: sections, and
+        starts by putting out the name of the doc section itself, but that
+        tends to duplicate a header already in the template file.
+        """
+        for section, text in args.sections.items():
+            # Skip sections that are in the nosymbol_table
+            if section in self.nosymbol:
+                continue
+
+            if out_docblock:
+                if not self.out_mode == self.OUTPUT_INCLUDE:
+                    self.data += f".. _{section}:\n\n"
+                    self.data += f'{self.lineprefix}**{section}**\n\n'
+            else:
+                self.data += f'{self.lineprefix}**{section}**\n\n'
+
+            self.print_lineno(args.sections_start_lines.get(section, 0))
+            self.output_highlight(text)
+            self.data += "\n"
+        self.data += "\n"
+
+    def out_doc(self, fname, name, args):
+        if not self.check_doc(name, args):
+            return
+        self.out_section(args, out_docblock=True)
+
+    def out_function(self, fname, name, args):
+
+        oldprefix = self.lineprefix
+        signature = ""
+
+        func_macro = args.get('func_macro', False)
+        if func_macro:
+            signature = name
+        else:
+            if args.get('functiontype'):
+                signature = args['functiontype'] + " "
+            signature += name + " ("
+
+        ln = args.declaration_start_line
+        count = 0
+        for parameter in args.parameterlist:
+            if count != 0:
+                signature += ", "
+            count += 1
+            dtype = args.parametertypes.get(parameter, "")
+
+            if function_pointer.search(dtype):
+                signature += function_pointer.group(1) + parameter + function_pointer.group(3)
+            else:
+                signature += dtype
+
+        if not func_macro:
+            signature += ")"
+
+        self.print_lineno(ln)
+        if args.get('typedef') or not args.get('functiontype'):
+            self.data += f".. c:macro:: {name}\n\n"
+
+            if args.get('typedef'):
+                self.data += "   **Typedef**: "
+                self.lineprefix = ""
+                self.output_highlight(args.get('purpose', ""))
+                self.data += "\n\n**Syntax**\n\n"
+                self.data += f"  ``{signature}``\n\n"
+            else:
+                self.data += f"``{signature}``\n\n"
+        else:
+            self.data += f".. c:function:: {signature}\n\n"
+
+        if not args.get('typedef'):
+            self.print_lineno(ln)
+            self.lineprefix = "   "
+            self.output_highlight(args.get('purpose', ""))
+            self.data += "\n"
+
+        # Put descriptive text into a container (HTML <div>) to help set
+        # function prototypes apart
+        self.lineprefix = "  "
+
+        if args.parameterlist:
+            self.data += ".. container:: kernelindent\n\n"
+            self.data += f"{self.lineprefix}**Parameters**\n\n"
+
+        for parameter in args.parameterlist:
+            parameter_name = KernRe(r'\[.*').sub('', parameter)
+            dtype = args.parametertypes.get(parameter, "")
+
+            if dtype:
+                self.data += f"{self.lineprefix}``{dtype}``\n"
+            else:
+                self.data += f"{self.lineprefix}``{parameter}``\n"
+
+            self.print_lineno(args.parameterdesc_start_lines.get(parameter_name, 0))
+
+            self.lineprefix = "    "
+            if parameter_name in args.parameterdescs and \
+               args.parameterdescs[parameter_name] != KernelDoc.undescribed:
+
+                self.output_highlight(args.parameterdescs[parameter_name])
+                self.data += "\n"
+            else:
+                self.data += f"{self.lineprefix}*undescribed*\n\n"
+            self.lineprefix = "  "
+
+        self.out_section(args)
+        self.lineprefix = oldprefix
+
+    def out_enum(self, fname, name, args):
+
+        oldprefix = self.lineprefix
+        ln = args.declaration_start_line
+
+        self.data += f"\n\n.. c:enum:: {name}\n\n"
+
+        self.print_lineno(ln)
+        self.lineprefix = "  "
+        self.output_highlight(args.get('purpose', ''))
+        self.data += "\n"
+
+        self.data += ".. container:: kernelindent\n\n"
+        outer = self.lineprefix + "  "
+        self.lineprefix = outer + "  "
+        self.data += f"{outer}**Constants**\n\n"
+
+        for parameter in args.parameterlist:
+            self.data += f"{outer}``{parameter}``\n"
+
+            if args.parameterdescs.get(parameter, '') != KernelDoc.undescribed:
+                self.output_highlight(args.parameterdescs[parameter])
+            else:
+                self.data += f"{self.lineprefix}*undescribed*\n\n"
+            self.data += "\n"
+
+        self.lineprefix = oldprefix
+        self.out_section(args)
+
+    def out_var(self, fname, name, args):
+        oldprefix = self.lineprefix
+        ln = args.declaration_start_line
+        full_proto = args.other_stuff.get("full_proto")
+        if not full_proto:
+            raise KeyError(f"Can't find full proto for {name} variable")
+
+        self.lineprefix = "  "
+
+        self.data += f"\n\n.. c:macro:: {name}\n\n{self.lineprefix}``{full_proto}``\n\n"
+
+        self.print_lineno(ln)
+        self.output_highlight(args.get('purpose', ''))
+        self.data += "\n"
+
+        if args.other_stuff["default_val"]:
+            self.data += f'{self.lineprefix}**Initialization**\n\n'
+            self.output_highlight(f'default: ``{args.other_stuff["default_val"]}``')
+
+        self.out_section(args)
+
+    def out_typedef(self, fname, name, args):
+
+        oldprefix = self.lineprefix
+        ln = args.declaration_start_line
+
+        self.data += f"\n\n.. c:type:: {name}\n\n"
+
+        self.print_lineno(ln)
+        self.lineprefix = "   "
+
+        self.output_highlight(args.get('purpose', ''))
+
+        self.data += "\n"
+
+        self.lineprefix = oldprefix
+        self.out_section(args)
+
+    def out_struct(self, fname, name, args):
+
+        purpose = args.get('purpose', "")
+        declaration = args.get('definition', "")
+        dtype = args.type
+        ln = args.declaration_start_line
+
+        self.data += f"\n\n.. c:{dtype}:: {name}\n\n"
+
+        self.print_lineno(ln)
+
+        oldprefix = self.lineprefix
+        self.lineprefix += "  "
+
+        self.output_highlight(purpose)
+        self.data += "\n"
+
+        self.data += ".. container:: kernelindent\n\n"
+        self.data += f"{self.lineprefix}**Definition**::\n\n"
+
+        self.lineprefix = self.lineprefix + "  "
+
+        declaration = declaration.replace("\t", self.lineprefix)
+
+        self.data += f"{self.lineprefix}{dtype} {name}" + ' {' + "\n"
+        self.data += f"{declaration}{self.lineprefix}" + "};\n\n"
+
+        self.lineprefix = "  "
+        self.data += f"{self.lineprefix}**Members**\n\n"
+        for parameter in args.parameterlist:
+            if not parameter or parameter.startswith("#"):
+                continue
+
+            parameter_name = parameter.split("[", maxsplit=1)[0]
+
+            if args.parameterdescs.get(parameter_name) == KernelDoc.undescribed:
+                continue
+
+            self.print_lineno(args.parameterdesc_start_lines.get(parameter_name, 0))
+
+            self.data += f"{self.lineprefix}``{parameter}``\n"
+
+            self.lineprefix = "    "
+            self.output_highlight(args.parameterdescs[parameter_name])
+            self.lineprefix = "  "
+
+            self.data += "\n"
+
+        self.data += "\n"
+
+        self.lineprefix = oldprefix
+        self.out_section(args)
+
+
+class ManFormat(OutputFormat):
+    """
+    Consts and functions used by man pages output.
+
+    This class has one mandatory parameter and some optional ones, which
+    are needed to define the title header contents:
+
+    ``modulename``
+        Defines the module name to be used at the troff ``.TH`` output.
+
+        This argument is optional. If not specified, it will be filled
+        with the directory which contains the documented file.
+
+    ``section``
+        Usually a numeric value from 0 to 9, but man pages also accept
+        some strings like "p".
+
+        Defauls to ``9``
+
+    ``manual``
+        Defaults to ``Kernel API Manual``.
+
+    The above controls the output of the corresponding fields on troff
+    title headers, which will be filled like this::
+
+        .TH "{name}" {section} "{date}" "{modulename}" "{manual}"
+
+    where ``name``` will match the API symbol name, and ``date`` will be
+    either the date where the Kernel was compiled or the current date
+    """
+
+    highlights = (
+        (type_constant, r"\1"),
+        (type_constant2, r"\1"),
+        (type_func, r"\\fB\1\\fP"),
+        (type_enum, r"\\fI\1\\fP"),
+        (type_struct, r"\\fI\1\\fP"),
+        (type_typedef, r"\\fI\1\\fP"),
+        (type_union, r"\\fI\1\\fP"),
+        (type_param, r"\\fI\1\\fP"),
+        (type_param_ref, r"\\fI\1\2\\fP"),
+        (type_member, r"\\fI\1\2\3\\fP"),
+        (type_fallback, r"\\fI\1\\fP")
+    )
+    blankline = ""
+
+    #: Allowed timestamp formats.
+    date_formats = [
+        "%a %b %d %H:%M:%S %Z %Y",
+        "%a %b %d %H:%M:%S %Y",
+        "%Y-%m-%d",
+        "%b %d %Y",
+        "%B %d %Y",
+        "%m %d %Y",
+    ]
+
+    def modulename(self, args):
+        if self._modulename:
+            return self._modulename
+
+        return os.path.dirname(args.fname)
+
+    def emit_th(self, name, args):
+        """Emit a title header line."""
+        title = name.strip()
+        module = self.modulename(args)
+
+        self.data += f'.TH "{title}" {self.section} "{self.date}" '
+        self.data += f'"{module}" "{self.manual}"\n'
+
+    def __init__(self, modulename=None, section="9", manual="Kernel API Manual"):
+        """
+        Creates class variables.
+
+        Not really mandatory, but it is a good coding style and makes
+        pylint happy.
+        """
+
+        super().__init__()
+
+        self._modulename = modulename
+        self.section = section
+        self.manual = manual
+
+        self.symbols = []
+
+        dt = None
+        tstamp = os.environ.get("KBUILD_BUILD_TIMESTAMP")
+        if tstamp:
+            for fmt in self.date_formats:
+                try:
+                    dt = datetime.strptime(tstamp, fmt)
+                    break
+                except ValueError:
+                    pass
+
+        if not dt:
+            dt = datetime.now()
+
+        self.date = dt.strftime("%B %Y")
+
+    def arg_name(self, args, name):
+        """
+        Return the name that will be used for the man page.
+
+        As we may have the same name on different namespaces,
+        prepend the data type for all types except functions and typedefs.
+
+        The doc section is special: it uses the modulename.
+        """
+
+        dtype = args.type
+
+        if dtype == "doc":
+            return name
+#            return os.path.basename(self.modulename(args))
+
+        if dtype in ["function", "typedef"]:
+            return name
+
+        return f"{dtype} {name}"
+
+    def set_symbols(self, symbols):
+        """
+        Get a list of all symbols from kernel_doc.
+
+        Man pages will uses it to add a SEE ALSO section with other
+        symbols at the same file.
+        """
+        self.symbols = symbols
+
+    def out_tail(self, fname, name, args):
+        """Adds a tail for all man pages."""
+
+        # SEE ALSO section
+        self.data += f'.SH "SEE ALSO"' + "\n.PP\n"
+        self.data += (f"Kernel file \\fB{args.fname}\\fR\n")
+        if len(self.symbols) >= 2:
+            cur_name = self.arg_name(args, name)
+
+            related = []
+            for arg in self.symbols:
+                out_name = self.arg_name(arg, arg.name)
+
+                if cur_name == out_name:
+                    continue
+
+                related.append(f"\\fB{out_name}\\fR(9)")
+
+            self.data += ",\n".join(related) + "\n"
+
+        # TODO: does it make sense to add other sections? Maybe
+        # REPORTING ISSUES? LICENSE?
+
+    def msg(self, fname, name, args):
+        """
+        Handles a single entry from kernel-doc parser.
+
+        Add a tail at the end of man pages output.
+        """
+        super().msg(fname, name, args)
+        self.out_tail(fname, name, args)
+
+        return self.data
+
+    def emit_table(self, colspec_row, rows):
+
+        if not rows:
+            return ""
+
+        out = ""
+        colspec = "\t".join(["l"] * len(rows[0]))
+
+        out += "\n.TS\n"
+        out += "box;\n"
+        out += f"{colspec}.\n"
+
+        if colspec_row:
+            out_row = []
+
+            for text in colspec_row:
+                out_row.append(f"\\fB{text}\\fP")
+
+            out += "\t".join(out_row) + "\n_\n"
+
+        for r in rows:
+            out += "\t".join(r) + "\n"
+
+        out += ".TE\n"
+
+        return out
+
+    def grid_table(self, lines, start):
+        """
+        Ancillary function to help handling a grid table inside the text.
+        """
+
+        i = start + 1
+        rows = []
+        colspec_row = None
+
+        while i < len(lines):
+            line = lines[i]
+
+            if KernRe(r"^\s*\|.*\|\s*$").match(line):
+                parts = []
+
+                for p in line.strip('|').split('|'):
+                    parts.append(p.strip())
+
+                rows.append(parts)
+
+            elif KernRe(r'^\+\=[\+\=]+\+\s*$').match(line):
+                if rows and rows[0]:
+                    if not colspec_row:
+                        colspec_row = [""] * len(rows[0])
+
+                    for j in range(0, len(rows[0])):
+                        content = []
+                        for row in rows:
+                            content.append(row[j])
+
+                        colspec_row[j] = " ".join(content)
+
+                    rows = []
+
+            elif KernRe(r"^\s*\+[-+]+\+.*$").match(line):
+                pass
+
+            else:
+                break
+
+            i += 1
+
+        return i, self.emit_table(colspec_row, rows)
+
+    def simple_table(self, lines, start):
+        """
+        Ancillary function to help handling a simple table inside the text.
+        """
+
+        i = start
+        rows = []
+        colspec_row = None
+
+        pos = []
+        for m in KernRe(r'\=+').finditer(lines[i]):
+            pos.append((m.start(), m.end() - 1))
+
+        i += 1
+        while i < len(lines):
+            line = lines[i]
+
+            if KernRe(r"^\s*[\=]+[ \t\=]+$").match(line):
+                i += 1
+                break
+
+            elif KernRe(r'^[\s=]+$').match(line):
+                if rows and rows[0]:
+                    if not colspec_row:
+                        colspec_row = [""] * len(rows[0])
+
+                    for j in range(0, len(rows[0])):
+                        content = []
+                        for row in rows:
+                            content.append(row[j])
+
+                        colspec_row[j] = " ".join(content)
+
+                    rows = []
+
+            else:
+                row = [""] * len(pos)
+
+                for j in range(0, len(pos)):
+                    start, end = pos[j]
+
+                    row[j] = line[start:end].strip()
+
+                rows.append(row)
+
+            i += 1
+
+        return i, self.emit_table(colspec_row, rows)
+
+    def code_block(self, lines, start):
+        """
+        Ensure that code blocks won't be messed up at the output.
+
+        By default, troff join lines at the same paragraph. Disable it,
+        on code blocks.
+        """
+
+        line = lines[start]
+
+        if "code-block" in line:
+            out = "\n.nf\n"
+        elif line.startswith("..") and line.endswith("::"):
+            #
+            # Handle note, warning, error, ... markups
+            #
+            line = line[2:-1].strip().upper()
+            out = f"\n.nf\n\\fB{line}\\fP\n"
+        elif line.endswith("::"):
+            out = line[:-1]
+            out += "\n.nf\n"
+        else:
+            # Just in case. Should never happen in practice
+            out = "\n.nf\n"
+
+        i = start + 1
+        ident = None
+
+        while i < len(lines):
+            line = lines[i]
+
+            m = KernRe(r"\S").match(line)
+            if not m:
+                out += line + "\n"
+                i += 1
+                continue
+
+            pos = m.start()
+            if not ident:
+                if pos > 0:
+                    ident = pos
+                else:
+                    out += "\n.fi\n"
+                    if i > start + 1:
+                        return i - 1, out
+                    else:
+                        # Just in case. Should never happen in practice
+                        return i, out
+
+            if pos >= ident:
+                out += line + "\n"
+                i += 1
+                continue
+
+            break
+
+        out += "\n.fi\n"
+        return i, out
+
+    def output_highlight(self, block):
+        """
+        Outputs a C symbol that may require being highlighted with
+        self.highlights variable using troff syntax.
+        """
+
+        contents = self.highlight_block(block)
+
+        if isinstance(contents, list):
+            contents = "\n".join(contents)
+
+        lines = contents.strip("\n").split("\n")
+        i = 0
+
+        while i < len(lines):
+            org_line = lines[i]
+
+            line = KernRe(r"^\s*").sub("", org_line)
+
+            if line:
+                if KernRe(r"^\+\-[-+]+\+.*$").match(line):
+                    i, text = self.grid_table(lines, i)
+                    self.data += text
+                    continue
+
+                if KernRe(r"^\=+[ \t]\=[ \t\=]+$").match(line):
+                    i, text = self.simple_table(lines, i)
+                    self.data += text
+                    continue
+
+                if line.endswith("::") or KernRe(r"\.\.\s+code-block.*::").match(line):
+                    i, text = self.code_block(lines, i)
+                    self.data += text
+                    continue
+
+                if line[0] == ".":
+                    self.data += "\\&" + line + "\n"
+                    i += 1
+                    continue
+
+                #
+                # Handle lists
+                #
+                line = KernRe(r'^[-*]\s+').sub(r'.IP \[bu]\n', line)
+                line = KernRe(r'^(\d+|a-z)[\.\)]\s+').sub(r'.IP \1\n', line)
+            else:
+                line = ".PP\n"
+
+            i += 1
+
+            self.data += line + "\n"
+
+    def out_doc(self, fname, name, args):
+        if not self.check_doc(name, args):
+            return
+
+        out_name = self.arg_name(args, name)
+
+        self.emit_th(out_name, args)
+
+        for section, text in args.sections.items():
+            self.data += f'.SH "{section}"' + "\n"
+            self.output_highlight(text)
+
+    def out_function(self, fname, name, args):
+
+        out_name = self.arg_name(args, name)
+
+        self.emit_th(out_name, args)
+
+        self.data += ".SH NAME\n"
+        self.data += f"{name} \\- {args['purpose']}\n"
+
+        self.data += ".SH SYNOPSIS\n"
+        if args.get('functiontype', ''):
+            self.data += f'.B "{args["functiontype"]}" {name}' + "\n"
+        else:
+            self.data += f'.B "{name}' + "\n"
+
+        count = 0
+        parenth = "("
+        post = ","
+
+        for parameter in args.parameterlist:
+            if count == len(args.parameterlist) - 1:
+                post = ");"
+
+            dtype = args.parametertypes.get(parameter, "")
+            if function_pointer.match(dtype):
+                # Pointer-to-function
+                self.data += f'".BI "{parenth}{function_pointer.group(1)}" " ") ({function_pointer.group(2)}){post}"' + "\n"
+            else:
+                dtype = KernRe(r'([^\*])$').sub(r'\1 ', dtype)
+
+                self.data += f'.BI "{parenth}{dtype}"  "{post}"' + "\n"
+            count += 1
+            parenth = ""
+
+        if args.parameterlist:
+            self.data += ".SH ARGUMENTS\n"
+
+        for parameter in args.parameterlist:
+            parameter_name = re.sub(r'\[.*', '', parameter)
+
+            self.data += f'.IP "{parameter}" 12' + "\n"
+            self.output_highlight(args.parameterdescs.get(parameter_name, ""))
+
+        for section, text in args.sections.items():
+            self.data += f'.SH "{section.upper()}"' + "\n"
+            self.output_highlight(text)
+
+    def out_enum(self, fname, name, args):
+        out_name = self.arg_name(args, name)
+
+        self.emit_th(out_name, args)
+
+        self.data += ".SH NAME\n"
+        self.data += f"enum {name} \\- {args['purpose']}\n"
+
+        self.data += ".SH SYNOPSIS\n"
+        self.data += f"enum {name}" + " {\n"
+
+        count = 0
+        for parameter in args.parameterlist:
+            self.data += f'.br\n.BI "    {parameter}"' + "\n"
+            if count == len(args.parameterlist) - 1:
+                self.data += "\n};\n"
+            else:
+                self.data += ", \n.br\n"
+
+            count += 1
+
+        self.data += ".SH Constants\n"
+
+        for parameter in args.parameterlist:
+            parameter_name = KernRe(r'\[.*').sub('', parameter)
+            self.data += f'.IP "{parameter}" 12' + "\n"
+            self.output_highlight(args.parameterdescs.get(parameter_name, ""))
+
+        for section, text in args.sections.items():
+            self.data += f'.SH "{section}"' + "\n"
+            self.output_highlight(text)
+
+    def out_var(self, fname, name, args):
+        out_name = self.arg_name(args, name)
+        full_proto = args.other_stuff["full_proto"]
+
+        self.emit_th(out_name, args)
+
+        self.data += ".SH NAME\n"
+        self.data += f"{name} \\- {args['purpose']}\n"
+
+        self.data += ".SH SYNOPSIS\n"
+        self.data += f"{full_proto}\n"
+
+        if args.other_stuff["default_val"]:
+            self.data += f'.SH "Initialization"' + "\n"
+            self.output_highlight(f'default: {args.other_stuff["default_val"]}')
+
+        for section, text in args.sections.items():
+            self.data += f'.SH "{section}"' + "\n"
+            self.output_highlight(text)
+
+    def out_typedef(self, fname, name, args):
+        module = self.modulename(args)
+        purpose = args.get('purpose')
+        out_name = self.arg_name(args, name)
+
+        self.emit_th(out_name, args)
+
+        self.data += ".SH NAME\n"
+        self.data += f"typedef {name} \\- {purpose}\n"
+
+        for section, text in args.sections.items():
+            self.data += f'.SH "{section}"' + "\n"
+            self.output_highlight(text)
+
+    def out_struct(self, fname, name, args):
+        module = self.modulename(args)
+        purpose = args.get('purpose')
+        definition = args.get('definition')
+        out_name = self.arg_name(args, name)
+
+        self.emit_th(out_name, args)
+
+        self.data += ".SH NAME\n"
+        self.data += f"{args.type} {name} \\- {purpose}\n"
+
+        # Replace tabs with two spaces and handle newlines
+        declaration = definition.replace("\t", "  ")
+        declaration = KernRe(r"\n").sub('"\n.br\n.BI "', declaration)
+
+        self.data += ".SH SYNOPSIS\n"
+        self.data += f"{args.type} {name} " + "{" + "\n.br\n"
+        self.data += f'.BI "{declaration}\n' + "};\n.br\n\n"
+
+        self.data += ".SH Members\n"
+        for parameter in args.parameterlist:
+            if parameter.startswith("#"):
+                continue
+
+            parameter_name = re.sub(r"\[.*", "", parameter)
+
+            if args.parameterdescs.get(parameter_name) == KernelDoc.undescribed:
+                continue
+
+            self.data += f'.IP "{parameter}" 12' + "\n"
+            self.output_highlight(args.parameterdescs.get(parameter_name))
+
+        for section, text in args.sections.items():
+            self.data += f'.SH "{section}"' + "\n"
+            self.output_highlight(text)
diff --git a/tools/lib/python/kdoc/kdoc_parser.py b/tools/lib/python/kdoc/kdoc_parser.py
new file mode 100644
index 000000000..d9ad1ddc8
--- /dev/null
+++ b/tools/lib/python/kdoc/kdoc_parser.py
@@ -0,0 +1,1779 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+#
+# pylint: disable=C0301,C0302,R0904,R0912,R0913,R0914,R0915,R0917,R1702
+
+"""
+Classes and functions related to reading a C language source or header FILE
+and extract embedded documentation comments from it.
+"""
+
+import sys
+import re
+import difflib
+from pprint import pformat
+
+from kdoc.c_lex import CTokenizer, tokenizer_set_log
+from kdoc.kdoc_re import KernRe
+from kdoc.kdoc_item import KdocItem
+
+#
+# Regular expressions used to parse kernel-doc markups at KernelDoc class.
+#
+# Let's declare them in lowercase outside any class to make it easier to
+# convert from the Perl script.
+#
+# As those are evaluated at the beginning, no need to cache them
+#
+
+# Allow whitespace at end of comment start.
+doc_start = KernRe(r'^/\*\*\s*$', cache=False)
+
+doc_end = KernRe(r'\*/', cache=False)
+doc_com = KernRe(r'\s*\*\s*', cache=False)
+doc_com_body = KernRe(r'\s*\* ?', cache=False)
+doc_decl = doc_com + KernRe(r'(\w+)', cache=False)
+
+# @params and a strictly limited set of supported section names
+# Specifically:
+#   Match @word:
+#         @...:
+#         @{section-name}:
+# while trying to not match literal block starts like "example::"
+#
+known_section_names = 'description|context|returns?|notes?|examples?'
+known_sections = KernRe(known_section_names, flags = re.I)
+doc_sect = doc_com + \
+    KernRe(r'\s*(@[.\w]+|@\.\.\.|' + known_section_names + r')\s*:([^:].*)?$',
+           flags=re.I, cache=False)
+
+doc_content = doc_com_body + KernRe(r'(.*)', cache=False)
+doc_inline_start = KernRe(r'^\s*/\*\*\s*$', cache=False)
+doc_inline_sect = KernRe(r'\s*\*\s*(@\s*[\w][\w\.]*\s*):(.*)', cache=False)
+doc_inline_end = KernRe(r'^\s*\*/\s*$', cache=False)
+doc_inline_oneline = KernRe(r'^\s*/\*\*\s*(@\s*[\w][\w\.]*\s*):\s*(.*)\s*\*/\s*$', cache=False)
+
+export_symbol = KernRe(r'^\s*EXPORT_SYMBOL(_GPL)?\s*\(\s*(\w+)\s*\)\s*', cache=False)
+export_symbol_ns = KernRe(r'^\s*EXPORT_SYMBOL_NS(_GPL)?\s*\(\s*(\w+)\s*,\s*"\S+"\)\s*', cache=False)
+
+type_param = KernRe(r"@(\w*((\.\w+)|(->\w+))*(\.\.\.)?)", cache=False)
+
+#
+# Tests for the beginning of a kerneldoc block in its various forms.
+#
+doc_block = doc_com + KernRe(r'DOC:\s*(.*)?', cache=False)
+doc_begin_data = KernRe(r"^\s*\*?\s*(struct|union|enum|typedef|var)\b\s*(\w*)", cache = False)
+doc_begin_func = KernRe(str(doc_com) +			# initial " * '
+                        r"(?:\w+\s*\*\s*)?" + 		# type (not captured)
+                        r'(?:define\s+)?' + 		# possible "define" (not captured)
+                        r'(\w+)\s*(?:\(\w*\))?\s*' +	# name and optional "(...)"
+                        r'(?:[-:].*)?$',		# description (not captured)
+                        cache = False)
+
+#
+# Ancillary functions
+#
+
+multi_space = KernRe(r'\s\s+')
+def trim_whitespace(s):
+    """
+    A little helper to get rid of excess white space.
+    """
+    return multi_space.sub(' ', s.strip())
+
+def trim_private_members(text):
+    """
+    Remove ``struct``/``enum`` members that have been marked "private".
+    """
+
+    tokens = CTokenizer(text)
+    return str(tokens)
+
+class state:
+    """
+    States used by the parser's state machine.
+    """
+
+    # Parser states
+    NORMAL        = 0        #: Normal code.
+    NAME          = 1        #: Looking for function name.
+    DECLARATION   = 2        #: We have seen a declaration which might not be done.
+    BODY          = 3        #: The body of the comment.
+    SPECIAL_SECTION = 4      #: Doc section ending with a blank line.
+    PROTO         = 5        #: Scanning prototype.
+    DOCBLOCK      = 6        #: Documentation block.
+    INLINE_NAME   = 7        #: Gathering doc outside main block.
+    INLINE_TEXT   = 8	     #: Reading the body of inline docs.
+
+    #: Names for each parser state.
+    name = [
+        "NORMAL",
+        "NAME",
+        "DECLARATION",
+        "BODY",
+        "SPECIAL_SECTION",
+        "PROTO",
+        "DOCBLOCK",
+        "INLINE_NAME",
+        "INLINE_TEXT",
+    ]
+
+
+SECTION_DEFAULT = "Description"  #: Default section.
+
+class KernelEntry:
+    """
+    Encapsulates a Kernel documentation entry.
+    """
+
+    def __init__(self, config, fname, ln):
+        self.config = config
+        self.fname = fname
+
+        self._contents = []
+        self.prototype = ""
+
+        self.warnings = []
+
+        self.parameterlist = []
+        self.parameterdescs = {}
+        self.parametertypes = {}
+        self.parameterdesc_start_lines = {}
+
+        self.sections_start_lines = {}
+        self.sections = {}
+
+        self.anon_struct_union = False
+
+        self.leading_space = None
+
+        self.fname = fname
+
+        # State flags
+        self.brcount = 0
+        self.declaration_start_line = ln + 1
+
+    #
+    # Management of section contents
+    #
+    def add_text(self, text):
+        """Add a new text to the entry contents list."""
+        self._contents.append(text)
+
+    def contents(self):
+        """Returns a string with all content texts that were added."""
+        return '\n'.join(self._contents) + '\n'
+
+    # TODO: rename to emit_message after removal of kernel-doc.pl
+    def emit_msg(self, ln, msg, *, warning=True):
+        """Emit a message."""
+
+        log_msg = f"{self.fname}:{ln} {msg}"
+
+        if not warning:
+            self.config.log.info(log_msg)
+            return
+
+        # Delegate warning output to output logic, as this way it
+        # will report warnings/info only for symbols that are output
+
+        self.warnings.append(log_msg)
+        return
+
+    def begin_section(self, line_no, title = SECTION_DEFAULT, dump = False):
+        """
+        Begin a new section.
+        """
+        if dump:
+            self.dump_section(start_new = True)
+        self.section = title
+        self.new_start_line = line_no
+
+    def dump_section(self, start_new=True):
+        """
+        Dumps section contents to arrays/hashes intended for that purpose.
+        """
+        #
+        # If we have accumulated no contents in the default ("description")
+        # section, don't bother.
+        #
+        if self.section == SECTION_DEFAULT and not self._contents:
+            return
+        name = self.section
+        contents = self.contents()
+
+        if type_param.match(name):
+            name = type_param.group(1)
+
+            self.parameterdescs[name] = contents
+            self.parameterdesc_start_lines[name] = self.new_start_line
+
+            self.new_start_line = 0
+
+        else:
+            if name in self.sections and self.sections[name] != "":
+                # Only warn on user-specified duplicate section names
+                if name != SECTION_DEFAULT:
+                    self.emit_msg(self.new_start_line,
+                                  f"duplicate section name '{name}'")
+                # Treat as a new paragraph - add a blank line
+                self.sections[name] += '\n' + contents
+            else:
+                self.sections[name] = contents
+                self.sections_start_lines[name] = self.new_start_line
+                self.new_start_line = 0
+
+#        self.config.log.debug("Section: %s : %s", name, pformat(vars(self)))
+
+        if start_new:
+            self.section = SECTION_DEFAULT
+            self._contents = []
+
+python_warning = False
+
+class KernelDoc:
+    """
+    Read a C language source or header FILE and extract embedded
+    documentation comments.
+    """
+
+    #: Name of context section.
+    section_context = "Context"
+
+    #: Name of return section.
+    section_return = "Return"
+
+    #: String to write when a parameter is not described.
+    undescribed = "-- undescribed --"
+
+    def __init__(self, config, fname, xforms, store_src=False):
+        """Initialize internal variables"""
+
+        self.fname = fname
+        self.config = config
+        self.xforms = xforms
+        self.store_src = store_src
+
+        tokenizer_set_log(self.config.log, f"{self.fname}: CMatch: ")
+
+        # Initial state for the state machines
+        self.state = state.NORMAL
+
+        # Store entry currently being processed
+        self.entry = None
+
+        # Place all potential outputs into an array
+        self.entries = []
+
+        #
+        # We need Python 3.7 for its "dicts remember the insertion
+        # order" guarantee
+        #
+        global python_warning
+        if (not python_warning and
+            sys.version_info.major == 3 and sys.version_info.minor < 7):
+
+            self.emit_msg(0,
+                          'Python 3.7 or later is required for correct results')
+            python_warning = True
+
+    def emit_msg(self, ln, msg, *, warning=True):
+        """Emit a message"""
+
+        if self.entry:
+            self.entry.emit_msg(ln, msg, warning=warning)
+            return
+
+        log_msg = f"{self.fname}:{ln} {msg}"
+
+        if warning:
+            self.config.log.warning(log_msg)
+        else:
+            self.config.log.info(log_msg)
+
+    def dump_section(self, start_new=True):
+        """
+        Dump section contents to arrays/hashes intended for that purpose.
+        """
+
+        if self.entry:
+            self.entry.dump_section(start_new)
+
+    # TODO: rename it to store_declaration after removal of kernel-doc.pl
+    def output_declaration(self, dtype, name, **args):
+        """
+        Store the entry into an entry array.
+
+        The actual output and output filters will be handled elsewhere.
+        """
+
+        item = KdocItem(name, self.fname, dtype,
+                        self.entry.declaration_start_line, **args)
+        item.warnings = self.entry.warnings
+
+        # Drop empty sections
+        # TODO: improve empty sections logic to emit warnings
+        sections = self.entry.sections
+        for section in ["Description", "Return"]:
+            if section in sections and not sections[section].rstrip():
+                del sections[section]
+        item.set_sections(sections, self.entry.sections_start_lines)
+        item.set_params(self.entry.parameterlist, self.entry.parameterdescs,
+                        self.entry.parametertypes,
+                        self.entry.parameterdesc_start_lines)
+        self.entries.append(item)
+
+        self.config.log.debug("Output: %s:%s = %s", dtype, name, pformat(args))
+
+    def emit_unused_warnings(self):
+        """
+        When the parser fails to produce a valid entry, it places some
+        warnings under `entry.warnings` that will be discarded when resetting
+        the state.
+
+        Ensure that those warnings are not lost.
+
+        .. note::
+
+              Because we are calling `config.warning()` here, those
+              warnings are not filtered by the `-W` parameters: they will all
+              be produced even when `-Wreturn`, `-Wshort-desc`, and/or
+              `-Wcontents-before-sections` are used.
+
+              Allowing those warnings to be filtered is complex, because it
+              would require storing them in a buffer and then filtering them
+              during the output step of the code, depending on the
+              selected symbols.
+        """
+        if self.entry and self.entry not in self.entries:
+            for log_msg in self.entry.warnings:
+                self.config.warning(log_msg)
+
+    def reset_state(self, ln):
+        """
+        Ancillary routine to create a new entry. It initializes all
+        variables used by the state machine.
+        """
+
+        self.emit_unused_warnings()
+
+        self.entry = KernelEntry(self.config, self.fname, ln)
+
+        # State flags
+        self.state = state.NORMAL
+
+    def push_parameter(self, ln, decl_type, param, dtype,
+                       org_arg, declaration_name):
+        """
+        Store parameters and their descriptions at self.entry.
+        """
+
+        if self.entry.anon_struct_union and dtype == "" and param == "}":
+            return  # Ignore the ending }; from anonymous struct/union
+
+        self.entry.anon_struct_union = False
+
+        param = KernRe(r'[\[\)].*').sub('', param, count=1)
+
+        #
+        # Look at various "anonymous type" cases.
+        #
+        if dtype == '':
+            if param.endswith("..."):
+                named_variadic = len(param) > 3
+                if named_variadic: # there is a name provided, use that
+                    #
+                    # If the user documented the parameter using the
+                    # ``@name...:`` form, the description is stored in
+                    # parameterdescs under the unstripped key.  Migrate
+                    # it to the stripped key so the user's text is not
+                    # silently dropped during output, and so the new
+                    # excess-parameter check in check_sections() does
+                    # not flag the unstripped key as orphaned.
+                    #
+                    orig = self.entry.parameterdescs.pop(param, None)
+                    param = param[:-3]
+                    if orig is not None and \
+                       not self.entry.parameterdescs.get(param):
+                        self.entry.parameterdescs[param] = orig
+                if not self.entry.parameterdescs.get(param):
+                    #
+                    # For a named variadic (e.g. ``args...``), emit the
+                    # standard "not described" warning before auto-filling
+                    # so a missing or mistyped ``@<name>:`` doc tag does
+                    # not go undetected.  The bare ``...`` form has no
+                    # natural name for the user to document and so always
+                    # gets the auto-generated text.
+                    #
+                    if named_variadic and decl_type == 'function':
+                        self.emit_msg(ln,
+                                      f"function parameter '{param}' "
+                                      f"not described in "
+                                      f"'{declaration_name}'")
+                    self.entry.parameterdescs[param] = "variable arguments"
+
+            elif (not param) or param == "void":
+                param = "void"
+                self.entry.parameterdescs[param] = "no arguments"
+
+            elif param in ["struct", "union"]:
+                # Handle unnamed (anonymous) union or struct
+                dtype = param
+                param = "{unnamed_" + param + "}"
+                self.entry.parameterdescs[param] = "anonymous\n"
+                self.entry.anon_struct_union = True
+
+        # Warn if parameter has no description
+        # (but ignore ones starting with # as these are not parameters
+        # but inline preprocessor statements)
+        if param not in self.entry.parameterdescs and not param.startswith("#"):
+            self.entry.parameterdescs[param] = self.undescribed
+
+            if "." not in param:
+                if decl_type == 'function':
+                    dname = f"{decl_type} parameter"
+                else:
+                    dname = f"{decl_type} member"
+
+                self.emit_msg(ln,
+                              f"{dname} '{param}' not described in '{declaration_name}'")
+
+        # Strip spaces from param so that it is one continuous string on
+        # parameterlist. This fixes a problem where check_sections()
+        # cannot find a parameter like "addr[6 + 2]" because it actually
+        # appears as "addr[6", "+", "2]" on the parameter list.
+        # However, it's better to maintain the param string unchanged for
+        # output, so just weaken the string compare in check_sections()
+        # to ignore "[blah" in a parameter string.
+
+        self.entry.parameterlist.append(param)
+        org_arg = KernRe(r'\s\s+').sub(' ', org_arg)
+        self.entry.parametertypes[param] = org_arg
+
+
+    def create_parameter_list(self, ln, decl_type, args,
+                              splitter, declaration_name):
+        """
+        Creates a list of parameters, storing them at self.entry.
+        """
+
+        # temporarily replace all commas inside function pointer definition
+        arg_expr = KernRe(r'(\([^\),]+),')
+        while arg_expr.search(args):
+            args = arg_expr.sub(r"\1#", args)
+
+        for arg in args.split(splitter):
+            # Ignore argument attributes
+            arg = KernRe(r'\sPOS0?\s').sub(' ', arg)
+
+            # Replace '[at_least ' with '[static '.  This allows sphinx to parse
+            # array parameter declarations like 'char A[at_least 4]', where
+            # 'at_least' is #defined to 'static' by the kernel headers.
+            arg = arg.replace('[at_least ', '[static ')
+
+            # Strip leading/trailing spaces
+            arg = arg.strip()
+            arg = KernRe(r'\s+').sub(' ', arg, count=1)
+
+            if arg.startswith('#'):
+                # Treat preprocessor directive as a typeless variable just to fill
+                # corresponding data structures "correctly". Catch it later in
+                # output_* subs.
+
+                # Treat preprocessor directive as a typeless variable
+                self.push_parameter(ln, decl_type, arg, "",
+                                    "", declaration_name)
+            #
+            # The pointer-to-function case.
+            #
+            elif KernRe(r'\(.+\)\s*\(').search(arg):
+                arg = arg.replace('#', ',')
+                r = KernRe(r'[^\(]+\(\*?\s*'  # Everything up to "(*"
+                           r'([\w\[\].]*)'    # Capture the name and possible [array]
+                           r'\s*\)')	      # Make sure the trailing ")" is there
+                if r.match(arg):
+                    param = r.group(1)
+                else:
+                    self.emit_msg(ln, f"Invalid param: {arg}")
+                    param = arg
+                dtype = arg.replace(param, '')
+                self.push_parameter(ln, decl_type, param, dtype, arg, declaration_name)
+            #
+            # The array-of-pointers case.  Dig the parameter name out from the middle
+            # of the declaration.
+            #
+            elif KernRe(r'\(.+\)\s*\[').search(arg):
+                r = KernRe(r'[^\(]+\(\s*\*\s*'		# Up to "(" and maybe "*"
+                           r'([\w.]*?)'			# The actual pointer name
+                           r'\s*(\[\s*\w+\s*\]\s*)*\)') # The [array portion]
+                if r.match(arg):
+                    param = r.group(1)
+                else:
+                    self.emit_msg(ln, f"Invalid param: {arg}")
+                    param = arg
+                dtype = arg.replace(param, '')
+                self.push_parameter(ln, decl_type, param, dtype, arg, declaration_name)
+            elif arg:
+                #
+                # Clean up extraneous spaces and split the string at commas; the first
+                # element of the resulting list will also include the type information.
+                #
+                arg = KernRe(r'\s*:\s*').sub(":", arg)
+                arg = KernRe(r'\s*\[').sub('[', arg)
+                args = KernRe(r'\s*,\s*').split(arg)
+                args[0] = re.sub(r'(\*+)\s*', r' \1', args[0])
+                #
+                # args[0] has a string of "type a".  If "a" includes an [array]
+                # declaration, we want to not be fooled by any white space inside
+                # the brackets, so detect and handle that case specially.
+                #
+                r = KernRe(r'^([^[\]]*\s+)(.*)$')
+                if r.match(args[0]):
+                    args[0] = r.group(2)
+                    dtype = r.group(1)
+                else:
+                    # No space in args[0]; this seems wrong but preserves previous behavior
+                    dtype = ''
+
+                bitfield_re = KernRe(r'(.*?):(\w+)')
+                for param in args:
+                    #
+                    # For pointers, shift the star(s) from the variable name to the
+                    # type declaration.
+                    #
+                    r = KernRe(r'^(\*+)\s*(.*)')
+                    if r.match(param):
+                        self.push_parameter(ln, decl_type, r.group(2),
+                                            f"{dtype} {r.group(1)}",
+                                            arg, declaration_name)
+                    #
+                    # Perform a similar shift for bitfields.
+                    #
+                    elif bitfield_re.search(param):
+                        if dtype != "":  # Skip unnamed bit-fields
+                            self.push_parameter(ln, decl_type, bitfield_re.group(1),
+                                                f"{dtype}:{bitfield_re.group(2)}",
+                                                arg, declaration_name)
+                    else:
+                        self.push_parameter(ln, decl_type, param, dtype,
+                                            arg, declaration_name)
+
+    def get_suggestions_hint(self, decl_name, possible_names):
+        # For decl name 'flags' or 'flgas', suggests 'substruct.flags'
+        submember_exact = []
+        submember_substrings = []
+        submember_suggestions = []
+        for possible_name in possible_names:
+            parts = possible_name.strip().split('.')
+            if len(parts) < 2:
+                continue
+
+            final_part = parts[-1]
+            if decl_name == final_part:
+                submember_exact.append(possible_name)
+            elif decl_name in final_part:
+                submember_substrings.append(possible_name)
+            elif difflib.get_close_matches(decl_name, [final_part]):
+                submember_suggestions.append(possible_name)
+
+        # For decl name 'flgas', suggests 'flags'
+        full_suggestions = difflib.get_close_matches(decl_name, possible_names)
+
+        # For decl name 'member', suggests 'longer_member'
+        full_substrings = [name for name in possible_names if decl_name in name]
+
+        ordered_lists = [
+            submember_exact,
+            submember_substrings,
+            submember_suggestions,
+            full_suggestions,
+            full_substrings,
+        ]
+
+        # Deduplicate but maintain order from most to least likely:
+        unique_suggestions = {}
+        for suggestion_list in ordered_lists:
+            for suggestion in suggestion_list:
+                unique_suggestions[suggestion] = None
+
+        suggestions = list(unique_suggestions.keys())
+        if not suggestions:
+            return ""
+
+        joined_suggestions = "', '".join(suggestions)
+        return f"(did you mean one of: '{joined_suggestions}')"
+
+    def check_sections(self, ln, decl_name, decl_type):
+        """
+        Check for errors inside sections, emitting warnings if not found
+        parameters are described.
+        """
+        for section in self.entry.sections:
+            if section not in self.entry.parameterlist and \
+               not known_sections.search(section):
+                hint = self.get_suggestions_hint(section, self.entry.parameterlist)
+                if decl_type == 'function':
+                    dname = f"{decl_type} parameter"
+                else:
+                    dname = f"{decl_type} member"
+                self.emit_msg(ln,
+                              f"Excess {dname} '{section}' description in '{decl_name}' {hint}".strip())
+
+        #
+        # Check that documented parameter names (from doc comments, including
+        # inline ``/** @member: */`` tags) actually match real members in
+        # the declaration.  This catches mismatched or stale kernel-doc
+        # member tags that don't correspond to any actual struct/union
+        # member or function parameter.
+        #
+        for param_name, desc in self.entry.parameterdescs.items():
+            # Skip auto-generated entries from push_parameter()
+            if desc == self.undescribed:
+                continue
+            if desc in ("no arguments", "anonymous\n", "variable arguments"):
+                continue
+            if param_name.startswith("{unnamed_"):
+                continue
+            if param_name in self.entry.parameterlist:
+                continue
+
+            hint = self.get_suggestions_hint(param_name, self.entry.parameterlist)
+            if decl_type == 'function':
+                dname = f"{decl_type} parameter"
+            else:
+                dname = f"{decl_type} member"
+            self.emit_msg(ln,
+                          f"Excess {dname} '{param_name}' description in '{decl_name}' {hint}".strip())
+
+    def check_return_section(self, ln, declaration_name, return_type):
+        """
+        If the function doesn't return void, warns about the lack of a
+        return description.
+        """
+
+        if not self.config.wreturn:
+            return
+
+        # Ignore an empty return type (It's a macro)
+        # Ignore functions with a "void" return type (but not "void *")
+        if not return_type or KernRe(r'void\s*\w*\s*$').search(return_type):
+            return
+
+        if not self.entry.sections.get("Return", None):
+            self.emit_msg(ln,
+                          f"No description found for return value of '{declaration_name}'")
+
+    def split_struct_proto(self, proto):
+        """
+        Split apart a structure prototype; returns (struct|union, name,
+        members) or ``None``.
+        """
+
+        type_pattern = r'(struct|union)'
+        qualifiers = [
+            "__attribute__",
+            "__packed",
+            "__aligned",
+            "____cacheline_aligned_in_smp",
+            "____cacheline_aligned",
+        ]
+        definition_body = r'\{(.*)\}\s*' + "(?:" + '|'.join(qualifiers) + ")?"
+
+        r = KernRe(type_pattern + r'\s+(\w+)\s*' + definition_body)
+        if r.search(proto):
+            return (r.group(1), r.group(2), r.group(3))
+        else:
+            r = KernRe(r'typedef\s+' + type_pattern + r'\s*' + definition_body + r'\s*(\w+)\s*;')
+            if r.search(proto):
+                return (r.group(1), r.group(3), r.group(2))
+        return None
+
+    def rewrite_struct_members(self, members):
+        """
+        Process ``struct``/``union`` members from the most deeply nested
+        outward.
+
+        Rewrite the members of a ``struct`` or ``union`` for easier formatting
+        later on. Among other things, this function will turn a member like::
+
+          struct { inner_members; } foo;
+
+        into::
+
+          struct foo; inner_members;
+        """
+
+        #
+        # The trick is in the ``^{`` below - it prevents a match of an outer
+        # ``struct``/``union`` until the inner one has been munged
+        # (removing the ``{`` in the process).
+        #
+        struct_members = KernRe(r'(struct|union)'   # 0: declaration type
+                                r'([^\{\};]+)' 	    # 1: possible name
+                                r'(\{)'
+                                r'([^\{\}]*)'       # 3: Contents of declaration
+                                r'(\})'
+                                r'([^\{\};]*)(;)')  # 5: Remaining stuff after declaration
+        tuples = struct_members.findall(members)
+        while tuples:
+            for t in tuples:
+                newmember = ""
+                oldmember = "".join(t) # Reconstruct the original formatting
+                dtype, name, lbr, content, rbr, rest, semi = t
+                #
+                # Pass through each field name, normalizing the form and formatting.
+                #
+                for s_id in rest.split(','):
+                    s_id = s_id.strip()
+                    newmember += f"{dtype} {s_id}; "
+                    #
+                    # Remove bitfield/array/pointer info, getting the bare name.
+                    #
+                    s_id = KernRe(r'[:\[].*').sub('', s_id)
+                    s_id = KernRe(r'^\s*\**(\S+)\s*').sub(r'\1', s_id)
+                    #
+                    # Pass through the members of this inner structure/union.
+                    #
+                    for arg in content.split(';'):
+                        arg = arg.strip()
+                        #
+                        # Look for (type)(*name)(args) - pointer to function
+                        #
+                        r = KernRe(r'^([^\(]+\(\*?\s*)([\w.]*)(\s*\).*)')
+                        if r.match(arg):
+                            dtype, name, extra = r.group(1), r.group(2), r.group(3)
+                            # Pointer-to-function
+                            if not s_id:
+                                # Anonymous struct/union
+                                newmember += f"{dtype}{name}{extra}; "
+                            else:
+                                newmember += f"{dtype}{s_id}.{name}{extra}; "
+                        #
+                        # Otherwise a non-function member.
+                        #
+                        else:
+                            #
+                            # Remove bitmap and array portions and spaces around commas
+                            #
+                            arg = KernRe(r':\s*\d+\s*').sub('', arg)
+                            arg = KernRe(r'\[.*\]').sub('', arg)
+                            arg = KernRe(r'\s*,\s*').sub(',', arg)
+                            #
+                            # Look for a normal decl - "type name[,name...]"
+                            #
+                            r = KernRe(r'(.*)\s+([\S+,]+)')
+                            if r.search(arg):
+                                for name in r.group(2).split(','):
+                                    name = KernRe(r'^\s*\**(\S+)\s*').sub(r'\1', name)
+                                    if not s_id:
+                                        # Anonymous struct/union
+                                        newmember += f"{r.group(1)} {name}; "
+                                    else:
+                                        newmember += f"{r.group(1)} {s_id}.{name}; "
+                            else:
+                                newmember += f"{arg}; "
+                #
+                # At the end of the s_id loop, replace the original declaration with
+                # the munged version.
+                #
+                members = members.replace(oldmember, newmember)
+            #
+            # End of the tuple loop - search again and see if there are outer members
+            # that now turn up.
+            #
+            tuples = struct_members.findall(members)
+        return members
+
+    def format_struct_decl(self, declaration):
+        """
+        Format the ``struct`` declaration into a standard form for inclusion
+        in the resulting docs.
+        """
+
+        #
+        # Insert newlines, get rid of extra spaces.
+        #
+        declaration = KernRe(r'([\{;])').sub(r'\1\n', declaration)
+        declaration = KernRe(r'\}\s+;').sub('};', declaration)
+        #
+        # Format inline enums with each member on its own line.
+        #
+        r = KernRe(r'(enum\s+\{[^\}]+),([^\n])')
+        while r.search(declaration):
+            declaration = r.sub(r'\1,\n\2', declaration)
+        #
+        # Now go through and supply the right number of tabs
+        # for each line.
+        #
+        def_args = declaration.split('\n')
+        level = 1
+        declaration = ""
+        for clause in def_args:
+            clause = KernRe(r'\s+').sub(' ', clause.strip(), count=1)
+            if clause:
+                if '}' in clause and level > 1:
+                    level -= 1
+                if not clause.startswith('#'):
+                    declaration += "\t" * level
+                declaration += "\t" + clause + "\n"
+                if "{" in clause and "}" not in clause:
+                    level += 1
+        return declaration
+
+
+    def dump_struct(self, ln, proto, source):
+        """
+        Store an entry for a ``struct`` or ``union``
+        """
+        #
+        # Do the basic parse to get the pieces of the declaration.
+        #
+        source = source
+        proto = trim_private_members(proto)
+        struct_parts = self.split_struct_proto(proto)
+        if not struct_parts:
+            self.emit_msg(ln, f"{proto} error: Cannot parse struct or union!")
+            return
+        decl_type, declaration_name, members = struct_parts
+
+        if self.entry.identifier != declaration_name:
+            self.emit_msg(ln, f"expecting prototype for {decl_type} {self.entry.identifier}. "
+                          f"Prototype was for {decl_type} {declaration_name} instead")
+            return
+        #
+        # Go through the list of members applying all of our transformations.
+        #
+        members = self.xforms.apply("struct", members)
+
+        #
+        # Deal with embedded struct and union members, and drop enums entirely.
+        #
+        declaration = members
+        members = self.rewrite_struct_members(members)
+        members = re.sub(r'(\{[^\{\}]*\})', '', members)
+        #
+        # Output the result and we are done.
+        #
+        self.create_parameter_list(ln, decl_type, members, ';',
+                                   declaration_name)
+        self.check_sections(ln, declaration_name, decl_type)
+        self.output_declaration(decl_type, declaration_name,
+                                source=source,
+                                definition=self.format_struct_decl(declaration),
+                                purpose=self.entry.declaration_purpose)
+
+    def dump_enum(self, ln, proto, source):
+        """
+        Store an ``enum`` inside self.entries array.
+        """
+        #
+        # Strip preprocessor directives.  Note that this depends on the
+        # trailing semicolon we added in process_proto_type().
+        #
+        source = source
+        proto = trim_private_members(proto)
+        proto = KernRe(r'#\s*((define|ifdef|if)\s+|endif)[^;]*;', flags=re.S).sub('', proto)
+        #
+        # Parse out the name and members of the enum.  Typedef form first.
+        #
+        r = KernRe(r'typedef\s+enum\s*\{(.*)\}\s*(\w*)\s*;')
+        if r.search(proto):
+            declaration_name = r.group(2)
+            members = r.group(1)
+        #
+        # Failing that, look for a straight enum
+        #
+        else:
+            r = KernRe(r'enum\s+(\w*)\s*\{(.*)\}')
+            if r.match(proto):
+                declaration_name = r.group(1)
+                members = r.group(2)
+        #
+        # OK, this isn't going to work.
+        #
+            else:
+                self.emit_msg(ln, f"{proto}: error: Cannot parse enum!")
+                return
+        #
+        # Make sure we found what we were expecting.
+        #
+        if self.entry.identifier != declaration_name:
+            if self.entry.identifier == "":
+                self.emit_msg(ln,
+                              f"{proto}: wrong kernel-doc identifier on prototype")
+            else:
+                self.emit_msg(ln,
+                              f"expecting prototype for enum {self.entry.identifier}. "
+                              f"Prototype was for enum {declaration_name} instead")
+            return
+
+        if not declaration_name:
+            declaration_name = "(anonymous)"
+        #
+        # Parse out the name of each enum member, and verify that we
+        # have a description for it.
+        #
+        member_set = set()
+        members = KernRe(r'\([^;)]*\)').sub('', members)
+        for arg in members.split(','):
+            arg = KernRe(r'^\s*(\w+).*').sub(r'\1', arg)
+            if not arg.strip():
+                continue
+
+            self.entry.parameterlist.append(arg)
+            if arg not in self.entry.parameterdescs:
+                self.entry.parameterdescs[arg] = self.undescribed
+                self.emit_msg(ln,
+                              f"Enum value '{arg}' not described in enum '{declaration_name}'")
+            member_set.add(arg)
+        #
+        # Ensure that every described member actually exists in the enum.
+        #
+        for k in self.entry.parameterdescs:
+            if k not in member_set:
+                self.emit_msg(ln,
+                              f"Excess enum value '@{k}' description in '{declaration_name}'")
+
+        self.output_declaration('enum', declaration_name,
+                                source=source,
+                                purpose=self.entry.declaration_purpose)
+
+    def dump_var(self, ln, proto, source):
+        """
+        Store variables that are part of kAPI.
+        """
+        VAR_ATTRIBS = [
+            "extern",
+            "const",
+        ]
+        OPTIONAL_VAR_ATTR = r"^(?:\b(?:" +"|".join(VAR_ATTRIBS) +r")\b\s*)*"
+
+        #
+        # Store the full prototype before modifying it
+        #
+        source = source
+        full_proto = proto
+        declaration_name = None
+
+        #
+        # Handle macro definitions
+        #
+        macro_prefixes = [
+            KernRe(r"DEFINE_[\w_]+\s*\(([\w_]+)\)"),
+        ]
+
+        for r in macro_prefixes:
+            match = r.search(proto)
+            if match:
+                declaration_name = match.group(1)
+                break
+
+        #
+        # Drop comments and macros to have a pure C prototype
+        #
+        if not declaration_name:
+            proto = self.xforms.apply("var", proto)
+
+        proto = proto.rstrip()
+
+        #
+        # Variable name is at the end of the declaration
+        #
+
+        default_val = None
+
+        r= KernRe(OPTIONAL_VAR_ATTR + r"\s*[\w_\s]*\s+(?:\*+)?([\w_]+)\s*[\d\]\[]*\s*(=.*)?")
+        if r.match(proto):
+            if not declaration_name:
+                declaration_name = r.group(1)
+
+            default_val = r.group(2)
+        else:
+            r= KernRe(OPTIONAL_VAR_ATTR + r"(?:[\w_\s]*)?\s+(?:\*+)?(?:[\w_]+)\s*[\d\]\[]*\s*(=.*)?")
+
+            if r.match(proto):
+                default_val = r.group(1)
+        if not declaration_name:
+           self.emit_msg(ln,f"{proto}: can't parse variable")
+           return
+
+        if default_val:
+            default_val = default_val.lstrip("=").strip()
+
+        self.output_declaration("var", declaration_name,
+                                source=source,
+                                full_proto=full_proto,
+                                default_val=default_val,
+                                purpose=self.entry.declaration_purpose)
+
+    def dump_declaration(self, ln, prototype, source):
+        """
+        Store a data declaration inside self.entries array.
+        """
+
+        if self.entry.decl_type == "enum":
+            self.dump_enum(ln, prototype, source)
+        elif self.entry.decl_type == "typedef":
+            self.dump_typedef(ln, prototype, source)
+        elif self.entry.decl_type in ["union", "struct"]:
+            self.dump_struct(ln, prototype, source)
+        elif self.entry.decl_type == "var":
+            self.dump_var(ln, prototype, source)
+        else:
+            # This would be a bug
+            self.emit_message(ln, f'Unknown declaration type: {self.entry.decl_type}')
+
+    def dump_function(self, ln, prototype, source):
+        """
+        Store a function or function macro inside self.entries array.
+        """
+
+        source = source
+        found = func_macro = False
+        return_type = ''
+        decl_type = 'function'
+
+        #
+        # If we have a macro, remove the "#define" at the front.
+        #
+        new_proto = KernRe(r"^#\s*define\s+").sub("", prototype)
+        if new_proto != prototype:
+            prototype = new_proto
+            #
+            # Dispense with the simple "#define A B" case here; the key
+            # is the space after the name of the symbol being defined.
+            # NOTE that the seemingly misnamed "func_macro" indicates a
+            # macro *without* arguments.
+            #
+            r = KernRe(r'^(\w+)\s+')
+            if r.search(prototype):
+                return_type = ''
+                declaration_name = r.group(1)
+                func_macro = True
+                found = True
+        else:
+            #
+            # Apply the initial transformations.
+            #
+            prototype = self.xforms.apply("func", prototype)
+
+        # Yes, this truly is vile.  We are looking for:
+        # 1. Return type (may be nothing if we're looking at a macro)
+        # 2. Function name
+        # 3. Function parameters.
+        #
+        # All the while we have to watch out for function pointer parameters
+        # (which IIRC is what the two sections are for), C types (these
+        # regexps don't even start to express all the possibilities), and
+        # so on.
+        #
+        # If you mess with these regexps, it's a good idea to check that
+        # the following functions' documentation still comes out right:
+        # - parport_register_device (function pointer parameters)
+        # - atomic_set (macro)
+        # - pci_match_device, __copy_to_user (long return type)
+
+        name = r'\w+'
+        type1 = r'(?:[\w\s]+)?'
+        type2 = r'(?:[\w\s]+\*+)+'
+        #
+        # Attempt to match first on (args) with no internal parentheses; this
+        # lets us easily filter out __acquires() and other post-args stuff.  If
+        # that fails, just grab the rest of the line to the last closing
+        # parenthesis.
+        #
+        proto_args = r'\(([^\(]*|.*)\)'
+        #
+        # (Except for the simple macro case) attempt to split up the prototype
+        # in the various ways we understand.
+        #
+        if not found:
+            patterns = [
+                rf'^()({name})\s*{proto_args}',
+                rf'^({type1})\s+({name})\s*{proto_args}',
+                rf'^({type2})\s*({name})\s*{proto_args}',
+            ]
+
+            for p in patterns:
+                r = KernRe(p)
+                if r.match(prototype):
+                    return_type = r.group(1)
+                    declaration_name = r.group(2)
+                    args = r.group(3)
+                    self.create_parameter_list(ln, decl_type, args, ',',
+                                               declaration_name)
+                    found = True
+                    break
+        #
+        # Parsing done; make sure that things are as we expect.
+        #
+        if not found:
+            self.emit_msg(ln,
+                          f"cannot understand function prototype: '{prototype}'")
+            return
+        if self.entry.identifier != declaration_name:
+            self.emit_msg(ln, f"expecting prototype for {self.entry.identifier}(). "
+                          f"Prototype was for {declaration_name}() instead")
+            return
+        self.check_sections(ln, declaration_name, "function")
+        self.check_return_section(ln, declaration_name, return_type)
+        #
+        # Store the result.
+        #
+        self.output_declaration(decl_type, declaration_name,
+                                source=source,
+                                typedef=('typedef' in return_type),
+                                functiontype=return_type,
+                                purpose=self.entry.declaration_purpose,
+                                func_macro=func_macro)
+
+
+    def dump_typedef(self, ln, proto, source):
+        """
+        Store a ``typedef`` inside self.entries array.
+        """
+        #
+        # We start by looking for function typedefs.
+        #
+        typedef_type = r'typedef((?:\s+[\w*]+\b){0,7}\s+(?:\w+\b|\*+))\s*'
+        typedef_ident = r'\*?\s*(\w\S+)\s*'
+        typedef_args = r'\s*\((.*)\);'
+
+        source = source
+
+        typedef1 = KernRe(typedef_type + r'\(' + typedef_ident + r'\)' + typedef_args)
+        typedef2 = KernRe(typedef_type + typedef_ident + typedef_args)
+
+        # Parse function typedef prototypes
+        for r in [typedef1, typedef2]:
+            if not r.match(proto):
+                continue
+
+            return_type = r.group(1).strip()
+            declaration_name = r.group(2)
+            args = r.group(3)
+
+            if self.entry.identifier != declaration_name:
+                self.emit_msg(ln,
+                              f"expecting prototype for typedef {self.entry.identifier}. Prototype was for typedef {declaration_name} instead")
+                return
+
+            self.create_parameter_list(ln, 'function', args, ',', declaration_name)
+
+            self.output_declaration('function', declaration_name,
+                                    source=source,
+                                    typedef=True,
+                                    functiontype=return_type,
+                                    purpose=self.entry.declaration_purpose)
+            return
+        #
+        # Not a function, try to parse a simple typedef.
+        #
+        r = KernRe(r'typedef.*\s+(\w+)\s*;')
+        if r.match(proto):
+            declaration_name = r.group(1)
+
+            if self.entry.identifier != declaration_name:
+                self.emit_msg(ln,
+                              f"expecting prototype for typedef {self.entry.identifier}. Prototype was for typedef {declaration_name} instead")
+                return
+
+            self.output_declaration('typedef', declaration_name,
+                                    source=source,
+                                    purpose=self.entry.declaration_purpose)
+            return
+
+        self.emit_msg(ln, "error: Cannot parse typedef!")
+
+    @staticmethod
+    def process_export(function_set, line):
+        """
+        process ``EXPORT_SYMBOL*`` tags
+
+        This method doesn't use any variable from the class, so declare it
+        with a staticmethod decorator.
+        """
+
+        # We support documenting some exported symbols with different
+        # names.  A horrible hack.
+        suffixes = [ '_noprof' ]
+
+        # Note: it accepts only one EXPORT_SYMBOL* per line, as having
+        # multiple export lines would violate Kernel coding style.
+
+        if export_symbol.search(line):
+            symbol = export_symbol.group(2)
+        elif export_symbol_ns.search(line):
+            symbol = export_symbol_ns.group(2)
+        else:
+            return False
+        #
+        # Found an export, trim out any special suffixes
+        #
+        for suffix in suffixes:
+            # Be backward compatible with Python < 3.9
+            if symbol.endswith(suffix):
+                symbol = symbol[:-len(suffix)]
+        function_set.add(symbol)
+        return True
+
+    def process_normal(self, ln, line, source):
+        """
+        STATE_NORMAL: looking for the ``/**`` to begin everything.
+        """
+
+        if not doc_start.match(line):
+            return
+
+        # start a new entry
+        self.reset_state(ln)
+
+        # next line is always the function name
+        self.state = state.NAME
+
+    def process_name(self, ln, line, source):
+        """
+        STATE_NAME: Looking for the "name - description" line
+        """
+        #
+        # Check for a DOC: block and handle them specially.
+        #
+        if doc_block.search(line):
+
+            if not doc_block.group(1):
+                self.entry.begin_section(ln, "Introduction")
+            else:
+                self.entry.begin_section(ln, doc_block.group(1))
+
+            self.entry.identifier = self.entry.section
+            self.state = state.DOCBLOCK
+        #
+        # Otherwise we're looking for a normal kerneldoc declaration line.
+        #
+        elif doc_decl.search(line):
+            self.entry.identifier = doc_decl.group(1)
+
+            # Test for data declaration
+            if doc_begin_data.search(line):
+                self.entry.decl_type = doc_begin_data.group(1)
+                self.entry.identifier = doc_begin_data.group(2)
+            #
+            # Look for a function description
+            #
+            elif doc_begin_func.search(line):
+                self.entry.identifier = doc_begin_func.group(1)
+                self.entry.decl_type = "function"
+            #
+            # We struck out.
+            #
+            else:
+                self.emit_msg(ln,
+                              f"This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst\n{line}")
+                self.state = state.NORMAL
+                return
+            #
+            # OK, set up for a new kerneldoc entry.
+            #
+            self.state = state.BODY
+            self.entry.identifier = self.entry.identifier.strip(" ")
+            # if there's no @param blocks need to set up default section here
+            self.entry.begin_section(ln + 1)
+            #
+            # Find the description portion, which *should* be there but
+            # isn't always.
+            # (We should be able to capture this from the previous parsing - someday)
+            #
+            r = KernRe("[-:](.*)")
+            if r.search(line):
+                self.entry.declaration_purpose = trim_whitespace(r.group(1))
+                self.state = state.DECLARATION
+            else:
+                self.entry.declaration_purpose = ""
+
+            if not self.entry.declaration_purpose and self.config.wshort_desc:
+                self.emit_msg(ln,
+                              f"missing initial short description on line:\n{line}")
+
+            if not self.entry.identifier and self.entry.decl_type != "enum":
+                self.emit_msg(ln,
+                              f"wrong kernel-doc identifier on line:\n{line}")
+                self.state = state.NORMAL
+
+            if self.config.verbose:
+                self.emit_msg(ln,
+                              f"Scanning doc for {self.entry.decl_type} {self.entry.identifier}",
+                                  warning=False)
+        #
+        # Failed to find an identifier. Emit a warning
+        #
+        else:
+            self.emit_msg(ln, f"Cannot find identifier on line:\n{line}")
+
+    def is_new_section(self, ln, line):
+        """
+        Helper function to determine if a new section is being started.
+        """
+        if doc_sect.search(line):
+            self.state = state.BODY
+            #
+            # Pick out the name of our new section, tweaking it if need be.
+            #
+            newsection = doc_sect.group(1)
+            if newsection.lower() == 'description':
+                newsection = 'Description'
+            elif newsection.lower() == 'context':
+                newsection = 'Context'
+                self.state = state.SPECIAL_SECTION
+            elif newsection.lower() in ["@return", "@returns",
+                                        "return", "returns"]:
+                newsection = "Return"
+                self.state = state.SPECIAL_SECTION
+            elif newsection[0] == '@':
+                self.state = state.SPECIAL_SECTION
+            #
+            # Initialize the contents, and get the new section going.
+            #
+            newcontents = doc_sect.group(2)
+            if not newcontents:
+                newcontents = ""
+            self.dump_section()
+            self.entry.begin_section(ln, newsection)
+            self.entry.leading_space = None
+
+            self.entry.add_text(newcontents.lstrip())
+            return True
+        return False
+
+    def is_comment_end(self, ln, line):
+        """
+        Helper function to detect (and effect) the end of a kerneldoc comment.
+        """
+        if doc_end.search(line):
+            self.dump_section()
+
+            # Look for doc_com + <text> + doc_end:
+            r = KernRe(r'\s*\*\s*[a-zA-Z_0-9:.]+\*/')
+            if r.match(line):
+                self.emit_msg(ln, f"suspicious ending line: {line}")
+
+            self.entry.prototype = ""
+            self.entry.new_start_line = ln + 1
+
+            self.state = state.PROTO
+            return True
+        return False
+
+
+    def process_decl(self, ln, line, source):
+        """
+        STATE_DECLARATION: We've seen the beginning of a declaration.
+        """
+        if self.is_new_section(ln, line) or self.is_comment_end(ln, line):
+            return
+        #
+        # Look for anything with the " * " line beginning.
+        #
+        if doc_content.search(line):
+            cont = doc_content.group(1)
+            #
+            # A blank line means that we have moved out of the declaration
+            # part of the comment (without any "special section" parameter
+            # descriptions).
+            #
+            if cont == "":
+                self.state = state.BODY
+            #
+            # Otherwise we have more of the declaration section to soak up.
+            #
+            else:
+                self.entry.declaration_purpose = \
+                    trim_whitespace(self.entry.declaration_purpose + ' ' + cont)
+        else:
+            # Unknown line, ignore
+            self.emit_msg(ln, f"bad line: {line}")
+
+
+    def process_special(self, ln, line, source):
+        """
+        STATE_SPECIAL_SECTION: a section ending with a blank line.
+        """
+        #
+        # If we have hit a blank line (only the " * " marker), then this
+        # section is done.
+        #
+        if KernRe(r"\s*\*\s*$").match(line):
+            self.entry.begin_section(ln, dump = True)
+            self.state = state.BODY
+            return
+        #
+        # Not a blank line, look for the other ways to end the section.
+        #
+        if self.is_new_section(ln, line) or self.is_comment_end(ln, line):
+            return
+        #
+        # OK, we should have a continuation of the text for this section.
+        #
+        if doc_content.search(line):
+            cont = doc_content.group(1)
+            #
+            # If the lines of text after the first in a special section have
+            # leading white space, we need to trim it out or Sphinx will get
+            # confused.  For the second line (the None case), see what we
+            # find there and remember it.
+            #
+            if self.entry.leading_space is None:
+                r = KernRe(r'^(\s+)')
+                if r.match(cont):
+                    self.entry.leading_space = len(r.group(1))
+                else:
+                    self.entry.leading_space = 0
+            #
+            # Otherwise, before trimming any leading chars, be *sure*
+            # that they are white space.  We should maybe warn if this
+            # isn't the case.
+            #
+            for i in range(0, self.entry.leading_space):
+                if cont[i] != " ":
+                    self.entry.leading_space = i
+                    break
+            #
+            # Add the trimmed result to the section and we're done.
+            #
+            self.entry.add_text(cont[self.entry.leading_space:])
+        else:
+            # Unknown line, ignore
+            self.emit_msg(ln, f"bad line: {line}")
+
+    def process_body(self, ln, line, source):
+        """
+        STATE_BODY: the bulk of a kerneldoc comment.
+        """
+        if self.is_new_section(ln, line) or self.is_comment_end(ln, line):
+            return
+
+        if doc_content.search(line):
+            cont = doc_content.group(1)
+            self.entry.add_text(cont)
+        else:
+            # Unknown line, ignore
+            self.emit_msg(ln, f"bad line: {line}")
+
+    def process_inline_name(self, ln, line, source):
+        """STATE_INLINE_NAME: beginning of docbook comments within a prototype."""
+
+        if doc_inline_sect.search(line):
+            self.entry.begin_section(ln, doc_inline_sect.group(1))
+            self.entry.add_text(doc_inline_sect.group(2).lstrip())
+            self.state = state.INLINE_TEXT
+        elif doc_inline_end.search(line):
+            self.dump_section()
+            self.state = state.PROTO
+        elif doc_content.search(line):
+            self.emit_msg(ln, f"Incorrect use of kernel-doc format: {line}")
+            self.state = state.PROTO
+
+            #
+            # Don't let it add partial comments at the code, as breaks the
+            # logic meant to remove comments from prototypes.
+            #
+            self.process_proto_type(ln, "/**\n" + line, source)
+        # else ... ??
+
+    def process_inline_text(self, ln, line, source):
+        """STATE_INLINE_TEXT: docbook comments within a prototype."""
+
+        if doc_inline_end.search(line):
+            self.dump_section()
+            self.state = state.PROTO
+        elif doc_content.search(line):
+            self.entry.add_text(doc_content.group(1))
+        # else ... ??
+
+    def syscall_munge(self, ln, proto):         # pylint: disable=W0613
+        """
+        Handle syscall definitions.
+        """
+
+        is_void = False
+
+        # Strip newlines/CR's
+        proto = re.sub(r'[\r\n]+', ' ', proto)
+
+        # Check if it's a SYSCALL_DEFINE0
+        if 'SYSCALL_DEFINE0' in proto:
+            is_void = True
+
+        # Replace SYSCALL_DEFINE with correct return type & function name
+        proto = KernRe(r'SYSCALL_DEFINE.*\(').sub('long sys_', proto)
+
+        r = KernRe(r'long\s+(sys_.*?),')
+        if r.search(proto):
+            proto = KernRe(',').sub('(', proto, count=1)
+        elif is_void:
+            proto = KernRe(r'\)').sub('(void)', proto, count=1)
+
+        # Now delete all of the odd-numbered commas in the proto
+        # so that argument types & names don't have a comma between them
+        count = 0
+        length = len(proto)
+
+        if is_void:
+            length = 0  # skip the loop if is_void
+
+        for ix in range(length):
+            if proto[ix] == ',':
+                count += 1
+                if count % 2 == 1:
+                    proto = proto[:ix] + ' ' + proto[ix + 1:]
+
+        return proto
+
+    def tracepoint_munge(self, ln, proto):
+        """
+        Handle tracepoint definitions.
+        """
+
+        tracepointname = None
+        tracepointargs = None
+
+        # Match tracepoint name based on different patterns
+        r = KernRe(r'TRACE_EVENT\((.*?),')
+        if r.search(proto):
+            tracepointname = r.group(1)
+
+        r = KernRe(r'DEFINE_SINGLE_EVENT\((.*?),')
+        if r.search(proto):
+            tracepointname = r.group(1)
+
+        r = KernRe(r'DEFINE_EVENT\((.*?),(.*?),')
+        if r.search(proto):
+            tracepointname = r.group(2)
+
+        if tracepointname:
+            tracepointname = tracepointname.lstrip()
+
+        r = KernRe(r'TP_PROTO\((.*?)\)')
+        if r.search(proto):
+            tracepointargs = r.group(1)
+
+        if not tracepointname or not tracepointargs:
+            self.emit_msg(ln,
+                          f"Unrecognized tracepoint format:\n{proto}\n")
+        else:
+            proto = f"static inline void trace_{tracepointname}({tracepointargs})"
+            self.entry.identifier = f"trace_{self.entry.identifier}"
+
+        return proto
+
+    def process_proto_function(self, ln, line, source):
+        """Ancillary routine to process a function prototype."""
+
+        # strip C99-style comments to end of line
+        line = KernRe(r"//.*$", re.S).sub('', line)
+        #
+        # Soak up the line's worth of prototype text, stopping at { or ; if present.
+        #
+        if KernRe(r'\s*#\s*define').match(line):
+            self.entry.prototype = line
+        elif not line.startswith('#'):   # skip other preprocessor stuff
+            r = KernRe(r'([^\{]*)')
+            if r.match(line):
+                self.entry.prototype += r.group(1) + " "
+        #
+        # If we now have the whole prototype, clean it up and declare victory.
+        #
+        if '{' in line or ';' in line or KernRe(r'\s*#\s*define').match(line):
+            # strip comments and surrounding spaces
+            self.entry.prototype = KernRe(r'/\*.*\*/').sub('', self.entry.prototype).strip()
+            #
+            # Handle self.entry.prototypes for function pointers like:
+            #       int (*pcs_config)(struct foo)
+            # by turning it into
+            #	    int pcs_config(struct foo)
+            #
+            r = KernRe(r'^(\S+\s+)\(\s*\*(\S+)\)')
+            self.entry.prototype = r.sub(r'\1\2', self.entry.prototype)
+            #
+            # Handle special declaration syntaxes
+            #
+            if 'SYSCALL_DEFINE' in self.entry.prototype:
+                self.entry.prototype = self.syscall_munge(ln,
+                                                          self.entry.prototype)
+            else:
+                r = KernRe(r'TRACE_EVENT|DEFINE_EVENT|DEFINE_SINGLE_EVENT')
+                if r.search(self.entry.prototype):
+                    self.entry.prototype = self.tracepoint_munge(ln,
+                                                                 self.entry.prototype)
+            #
+            # ... and we're done
+            #
+            self.dump_function(ln, self.entry.prototype, source)
+            self.reset_state(ln)
+
+    def process_proto_type(self, ln, line, source):
+        """
+        Ancillary routine to process a type.
+        """
+
+        # Strip C99-style comments and surrounding whitespace
+        line = KernRe(r"//.*$", re.S).sub('', line).strip()
+        if not line:
+            return # nothing to see here
+
+        # To distinguish preprocessor directive from regular declaration later.
+        if line.startswith('#'):
+            line += ";"
+        #
+        # Split the declaration on any of { } or ;, and accumulate pieces
+        # until we hit a semicolon while not inside {brackets}
+        #
+        r = KernRe(r'(.*?)([{};])')
+        for chunk in r.split(line):
+            if chunk:  # Ignore empty matches
+                self.entry.prototype += chunk
+                #
+                # This cries out for a match statement ... someday after we can
+                # drop Python 3.9 ...
+                #
+                if chunk == '{':
+                    self.entry.brcount += 1
+                elif chunk == '}':
+                    self.entry.brcount -= 1
+                elif chunk == ';' and self.entry.brcount <= 0:
+                    self.dump_declaration(ln, self.entry.prototype, source)
+                    self.reset_state(ln)
+                    return
+        #
+        # We hit the end of the line while still in the declaration; put
+        # in a space to represent the newline.
+        #
+        self.entry.prototype += ' '
+
+    def process_proto(self, ln, line, source):
+        """STATE_PROTO: reading a function/whatever prototype."""
+
+        if doc_inline_oneline.search(line):
+            self.entry.begin_section(ln, doc_inline_oneline.group(1))
+            self.entry.add_text(doc_inline_oneline.group(2))
+            self.dump_section()
+
+        elif doc_inline_start.search(line):
+            self.state = state.INLINE_NAME
+
+        elif self.entry.decl_type == 'function':
+            self.process_proto_function(ln, line, source)
+
+        else:
+            self.process_proto_type(ln, line, source)
+
+    def process_docblock(self, ln, line, source):
+        """STATE_DOCBLOCK: within a ``DOC:`` block."""
+
+        if doc_end.search(line):
+            self.dump_section()
+            self.output_declaration("doc", self.entry.identifier,
+                                    source=source)
+            self.reset_state(ln)
+
+        elif doc_content.search(line):
+            self.entry.add_text(doc_content.group(1))
+
+    def parse_export(self):
+        """
+        Parses ``EXPORT_SYMBOL*`` macros from a single Kernel source file.
+        """
+
+        export_table = set()
+
+        try:
+            with open(self.fname, "r", encoding="utf8",
+                      errors="backslashreplace") as fp:
+
+                for line in fp:
+                    self.process_export(export_table, line)
+
+        except IOError:
+            return None
+
+        return export_table
+
+    #: The state/action table telling us which function to invoke in each state.
+    state_actions = {
+        state.NORMAL:			process_normal,
+        state.NAME:			process_name,
+        state.BODY:			process_body,
+        state.DECLARATION:		process_decl,
+        state.SPECIAL_SECTION:		process_special,
+        state.INLINE_NAME:		process_inline_name,
+        state.INLINE_TEXT:		process_inline_text,
+        state.PROTO:			process_proto,
+        state.DOCBLOCK:			process_docblock,
+        }
+
+    def parse_kdoc(self):
+        """
+        Open and process each line of a C source file.
+        The parsing is controlled via a state machine, and the line is passed
+        to a different process function depending on the state. The process
+        function may update the state as needed.
+
+        Besides parsing kernel-doc tags, it also parses export symbols.
+        """
+
+        prev = ""
+        prev_ln = None
+        export_table = set()
+        self.state = state.NORMAL
+        source = ""
+
+        try:
+            with open(self.fname, "r", encoding="utf8",
+                      errors="backslashreplace") as fp:
+                for ln, line in enumerate(fp):
+
+                    line = line.expandtabs().strip("\n")
+
+                    # Group continuation lines on prototypes
+                    if self.state == state.PROTO:
+                        if line.endswith("\\"):
+                            prev += line.rstrip("\\")
+                            if not prev_ln:
+                                prev_ln = ln
+                            continue
+
+                        if prev:
+                            ln = prev_ln
+                            line = prev + line
+                            prev = ""
+                            prev_ln = None
+
+                    self.config.log.debug("%d %s: %s",
+                                          ln, state.name[self.state],
+                                          line)
+
+                    if self.store_src:
+                        if source and self.state == state.NORMAL:
+                            source = ""
+                        elif self.state != state.NORMAL:
+                            source += line + "\n"
+
+                    # This is an optimization over the original script.
+                    # There, when export_file was used for the same file,
+                    # it was read twice. Here, we use the already-existing
+                    # loop to parse exported symbols as well.
+                    #
+                    if (self.state != state.NORMAL) or \
+                       not self.process_export(export_table, line):
+                        prev_state = self.state
+                        # Hand this line to the appropriate state handler
+                        self.state_actions[self.state](self, ln, line, source)
+                        if prev_state == state.NORMAL and self.state != state.NORMAL:
+                            source += line + "\n"
+
+            self.emit_unused_warnings()
+
+        except OSError:
+            self.config.log.error(f"Error: Cannot open file {self.fname}")
+
+        return export_table, self.entries
diff --git a/tools/lib/python/kdoc/kdoc_re.py b/tools/lib/python/kdoc/kdoc_re.py
new file mode 100644
index 000000000..28292efe2
--- /dev/null
+++ b/tools/lib/python/kdoc/kdoc_re.py
@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025: Mauro Carvalho Chehab <mchehab@kernel.org>.
+
+"""
+Regular expression ancillary classes.
+
+Those help caching regular expressions and do matching for kernel-doc.
+"""
+
+import re
+
+# Local cache for regular expressions
+re_cache = {}
+
+
+class KernRe:
+    """
+    Helper class to simplify regex declaration and usage.
+
+    It calls re.compile for a given pattern. It also allows adding
+    regular expressions and define sub at class init time.
+
+    Regular expressions can be cached via an argument, helping to speedup
+    searches.
+    """
+
+    def _add_regex(self, string, flags):
+        """
+        Adds a new regex or reuses it from the cache.
+        """
+        self.regex = re_cache.get(string, None)
+        if not self.regex:
+            self.regex = re.compile(string, flags=flags)
+            if self.cache:
+                re_cache[string] = self.regex
+
+    def __init__(self, string, cache=True, flags=0):
+        """
+        Compile a regular expression and initialize internal vars.
+        """
+
+        self.cache = cache
+        self.last_match = None
+
+        self._add_regex(string, flags)
+
+    def __str__(self):
+        """
+        Return the regular expression pattern.
+        """
+        return self.regex.pattern
+
+    def __repr__(self):
+        """
+        Returns a displayable version of the class init.
+        """
+
+        flag_map = {
+            re.IGNORECASE: "re.I",
+            re.MULTILINE: "re.M",
+            re.DOTALL: "re.S",
+            re.VERBOSE: "re.X",
+        }
+
+        flags = []
+        for flag, name in flag_map.items():
+            if self.regex.flags & flag:
+                flags.append(name)
+
+        flags_name = " | ".join(flags)
+
+        max_len = 60
+        pattern = ""
+        for pos in range(0, len(self.regex.pattern), max_len):
+            pattern += '"' + self.regex.pattern[pos:max_len + pos] + '" '
+
+        if flags_name:
+            return f'KernRe({pattern}, {flags_name})'
+        else:
+            return f'KernRe({pattern})'
+
+    def __add__(self, other):
+        """
+        Allows adding two regular expressions into one.
+        """
+
+        return KernRe(str(self) + str(other), cache=self.cache or other.cache,
+                  flags=self.regex.flags | other.regex.flags)
+
+    def match(self, string):
+        """
+        Handles a re.match storing its results.
+        """
+
+        self.last_match = self.regex.match(string)
+        return self.last_match
+
+    def search(self, string):
+        """
+        Handles a re.search storing its results.
+        """
+
+        self.last_match = self.regex.search(string)
+        return self.last_match
+
+    def finditer(self,  string):
+        """
+        Alias to re.finditer.
+        """
+
+        return self.regex.finditer(string)
+
+    def findall(self, string):
+        """
+        Alias to re.findall.
+        """
+
+        return self.regex.findall(string)
+
+    def split(self, string):
+        """
+        Alias to re.split.
+        """
+
+        return self.regex.split(string)
+
+    def sub(self, sub, string, count=0):
+        """
+        Alias to re.sub.
+        """
+
+        return self.regex.sub(sub, string, count=count)
+
+    def group(self, num):
+        """
+        Returns the group results of the last match.
+        """
+
+        return self.last_match.group(num)
+
+    def groups(self):
+        """
+        Returns the group results of the last match
+        """
+
+        return self.last_match.groups()
diff --git a/tools/lib/python/kdoc/kdoc_yaml_file.py b/tools/lib/python/kdoc/kdoc_yaml_file.py
new file mode 100644
index 000000000..0be020d50
--- /dev/null
+++ b/tools/lib/python/kdoc/kdoc_yaml_file.py
@@ -0,0 +1,178 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2026: Mauro Carvalho Chehab <mchehab@kernel.org>.
+
+import os
+
+from kdoc.kdoc_output import ManFormat, RestFormat
+
+
+class KDocTestFile():
+    """
+    Handles the logic needed to store kernel‑doc output inside a YAML file.
+     Useful for unit tests and regression tests.
+    """
+
+    def __init__(self, config, yaml_file, yaml_content):
+        #
+        # Bail out early if yaml is not available
+        #
+        try:
+            import yaml
+        except ImportError:
+            sys.exit("Warning: yaml package not available. Aborting it.")
+
+        self.config = config
+        self.test_file = os.path.expanduser(yaml_file)
+        self.yaml_content = yaml_content
+        self.test_names = set()
+
+        self.tests = []
+
+        out_dir = os.path.dirname(self.test_file)
+        if out_dir and not os.path.isdir(out_dir):
+            sys.exit(f"Directory {out_dir} doesn't exist.")
+
+        self.out_style = []
+
+        if "man" in self.yaml_content:
+            out_style = ManFormat()
+            out_style.set_config(self.config)
+
+            self.out_style.append(out_style)
+
+        if "rst" in self.yaml_content:
+            out_style = RestFormat()
+            out_style.set_config(self.config)
+
+            self.out_style.append(out_style)
+
+    def set_filter(self, export, internal, symbol, nosymbol,
+                   function_table, enable_lineno, no_doc_sections):
+        """
+        Set filters at the output classes.
+        """
+        for out_style in self.out_style:
+            out_style.set_filter(export, internal, symbol,
+                                 nosymbol, function_table,
+                                 enable_lineno, no_doc_sections)
+
+    @staticmethod
+    def get_kdoc_item(arg, start_line=1):
+
+        d = vars(arg)
+
+        declaration_start_line = d.get("declaration_start_line")
+        if not declaration_start_line:
+            return d
+
+        d["declaration_start_line"] = start_line
+
+        parameterdesc_start_lines = d.get("parameterdesc_start_lines")
+        if parameterdesc_start_lines:
+            for key in parameterdesc_start_lines:
+                ln = parameterdesc_start_lines[key]
+                ln += start_line - declaration_start_line
+
+                parameterdesc_start_lines[key] = ln
+
+        sections_start_lines = d.get("sections_start_lines")
+        if sections_start_lines:
+            for key in sections_start_lines:
+                ln = sections_start_lines[key]
+                ln += start_line - declaration_start_line
+
+                sections_start_lines[key] = ln
+
+        return d
+
+    def output_symbols(self, fname, symbols):
+        """
+        Store source, symbols and output strings at self.tests.
+        """
+
+        #
+        # KdocItem needs to be converted into dicts
+        #
+        kdoc_item = []
+        expected = []
+
+        #
+        # Source code didn't produce any symbol
+        #
+        if not symbols:
+            return
+
+        expected_dict = {}
+        start_line=1
+
+        for arg in symbols:
+            source = arg.get("source", "")
+
+            if arg and "KdocItem" in self.yaml_content:
+                msg = self.get_kdoc_item(arg)
+
+                other_stuff = msg.get("other_stuff", {})
+                if "source" in other_stuff:
+                    del other_stuff["source"]
+
+                expected_dict["kdoc_item"] = msg
+
+            base_name = arg.name
+            if not base_name:
+                base_name = fname
+            base_name = base_name.lower().replace(".", "_").replace("/", "_")
+
+
+            # Don't add duplicated names
+            i = 0
+            name = base_name
+            while name in self.test_names:
+                i += 1
+                name = f"{base_name}_{i:03d}"
+
+            self.test_names.add(name)
+
+            for out_style in self.out_style:
+                if isinstance(out_style, ManFormat):
+                    key = "man"
+                else:
+                    key = "rst"
+
+                expected_dict[key]= out_style.output_symbols(fname, [arg]).strip()
+
+            test = {
+                "name": name,
+                "description": f"{fname} line {arg.declaration_start_line}",
+                "fname": fname,
+                "source": source,
+                "expected": [expected_dict]
+            }
+
+            self.tests.append(test)
+
+            expected_dict = {}
+
+    def write(self):
+        """
+        Output the content of self.tests to self.test_file.
+        """
+        import yaml
+
+        # Helper function to better handle multilines
+        def str_presenter(dumper, data):
+            if "\n" in data:
+                return dumper.represent_scalar("tag:yaml.org,2002:str", data, style="|")
+
+            return dumper.represent_scalar("tag:yaml.org,2002:str", data)
+
+        # Register the representer
+        yaml.add_representer(str, str_presenter)
+
+        data = {"tests": self.tests}
+
+        with open(self.test_file, "w", encoding="utf-8") as fp:
+            yaml.dump(data, fp,
+                      sort_keys=False, width=120, indent=2,
+                      default_flow_style=False, allow_unicode=True,
+                      explicit_start=False, explicit_end=False)
diff --git a/tools/lib/python/kdoc/latex_fonts.py b/tools/lib/python/kdoc/latex_fonts.py
new file mode 100755
index 000000000..1d04cbda1
--- /dev/null
+++ b/tools/lib/python/kdoc/latex_fonts.py
@@ -0,0 +1,184 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) Akira Yokosawa, 2024
+#
+# Ported to Python by (c) Mauro Carvalho Chehab, 2025
+
+"""
+Detect problematic Noto CJK variable fonts
+==========================================
+
+For ``make pdfdocs``, reports of build errors of translations.pdf started
+arriving early 2024 [1]_ [2]_.  It turned out that Fedora and openSUSE
+tumbleweed have started deploying variable-font [3]_ format of "Noto CJK"
+fonts [4]_ [5]_.  For PDF, a LaTeX package named xeCJK is used for CJK
+(Chinese, Japanese, Korean) pages.  xeCJK requires XeLaTeX/XeTeX, which
+does not (and likely never will) understand variable fonts for historical
+reasons.
+
+The build error happens even when both of variable- and non-variable-format
+fonts are found on the build system.  To make matters worse, Fedora enlists
+variable "Noto CJK" fonts in the requirements of langpacks-ja, -ko, -zh_CN,
+-zh_TW, etc.  Hence developers who have interest in CJK pages are more
+likely to encounter the build errors.
+
+This script is invoked from the error path of "make pdfdocs" and emits
+suggestions if variable-font files of "Noto CJK" fonts are in the list of
+fonts accessible from XeTeX.
+
+.. [1] https://lore.kernel.org/r/8734tqsrt7.fsf@meer.lwn.net/
+.. [2] https://lore.kernel.org/r/1708585803.600323099@f111.i.mail.ru/
+.. [3] https://en.wikipedia.org/wiki/Variable_font
+.. [4] https://fedoraproject.org/wiki/Changes/Noto_CJK_Variable_Fonts
+.. [5] https://build.opensuse.org/request/show/1157217
+
+Workarounds for building translations.pdf
+-----------------------------------------
+
+* Denylist "variable font" Noto CJK fonts.
+
+  - Create $HOME/deny-vf/fontconfig/fonts.conf from template below, with
+    tweaks if necessary.  Remove leading "".
+
+  - Path of fontconfig/fonts.conf can be overridden by setting an env
+    variable FONTS_CONF_DENY_VF.
+
+    * Template::
+
+        <?xml version="1.0"?>
+        <!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
+        <fontconfig>
+        <!--
+        Ignore variable-font glob (not to break xetex)
+        -->
+            <selectfont>
+                <rejectfont>
+                    <!--
+                        for Fedora
+                    -->
+                    <glob>/usr/share/fonts/google-noto-*-cjk-vf-fonts</glob>
+                    <!--
+                        for openSUSE tumbleweed
+                    -->
+                    <glob>/usr/share/fonts/truetype/Noto*CJK*-VF.otf</glob>
+                </rejectfont>
+            </selectfont>
+        </fontconfig>
+
+    The denylisting is activated for "make pdfdocs".
+
+* For skipping CJK pages in PDF
+
+  - Uninstall texlive-xecjk.
+    Denylisting is not needed in this case.
+
+* For printing CJK pages in PDF
+
+  - Need non-variable "Noto CJK" fonts.
+
+    * Fedora
+
+      - google-noto-sans-cjk-fonts
+      - google-noto-serif-cjk-fonts
+
+    * openSUSE tumbleweed
+
+      - Non-variable "Noto CJK" fonts are not available as distro packages
+        as of April, 2024.  Fetch a set of font files from upstream Noto
+        CJK Font released at:
+
+          https://github.com/notofonts/noto-cjk/tree/main/Sans#super-otc
+
+        and at:
+
+          https://github.com/notofonts/noto-cjk/tree/main/Serif#super-otc
+
+        then uncompress and deploy them.
+      - Remember to update fontconfig cache by running fc-cache.
+
+.. caution::
+    Uninstalling "variable font" packages can be dangerous.
+    They might be depended upon by other packages important for your work.
+    Denylisting should be less invasive, as it is effective only while
+    XeLaTeX runs in "make pdfdocs".
+"""
+
+import os
+import re
+import subprocess
+import textwrap
+import sys
+
+class LatexFontChecker:
+    """
+    Detect problems with CJK variable fonts that affect PDF builds for
+    translations.
+    """
+
+    def __init__(self, deny_vf=None):
+        if not deny_vf:
+            deny_vf = os.environ.get('FONTS_CONF_DENY_VF', "~/deny-vf")
+
+        self.environ = os.environ.copy()
+        self.environ['XDG_CONFIG_HOME'] = os.path.expanduser(deny_vf)
+
+        self.re_cjk = re.compile(r"([^:]+):\s*Noto\s+(Sans|Sans Mono|Serif) CJK")
+
+    def description(self):
+        """
+        Returns module description.
+        """
+        return __doc__
+
+    def get_noto_cjk_vf_fonts(self):
+        """
+        Get Noto CJK fonts.
+        """
+
+        cjk_fonts = set()
+        cmd = ["fc-list", ":", "file", "family", "variable"]
+        try:
+            result = subprocess.run(cmd,stdout=subprocess.PIPE,
+                                    stderr=subprocess.PIPE,
+                                    universal_newlines=True,
+                                    env=self.environ,
+                                    check=True)
+
+        except subprocess.CalledProcessError as exc:
+            sys.exit(f"Error running fc-list: {repr(exc)}")
+
+        for line in result.stdout.splitlines():
+            if 'variable=True' not in line:
+                continue
+
+            match = self.re_cjk.search(line)
+            if match:
+                cjk_fonts.add(match.group(1))
+
+        return sorted(cjk_fonts)
+
+    def check(self):
+        """
+        Check for problems with CJK fonts.
+        """
+
+        fonts = textwrap.indent("\n".join(self.get_noto_cjk_vf_fonts()), "    ")
+        if not fonts:
+            return None
+
+        rel_file = os.path.relpath(__file__, os.getcwd())
+
+        msg = "=" * 77 + "\n"
+        msg += 'XeTeX is confused by "variable font" files listed below:\n'
+        msg += fonts + "\n"
+        msg += textwrap.dedent(f"""
+                For CJK pages in PDF, they need to be hidden from XeTeX by denylisting.
+                Or, CJK pages can be skipped by uninstalling texlive-xecjk.
+
+                For more info on denylisting, other options, and variable font, run:
+
+                    tools/docs/check-variable-fonts.py -h
+            """)
+        msg += "=" * 77
+
+        return msg
diff --git a/tools/lib/python/kdoc/parse_data_structs.py b/tools/lib/python/kdoc/parse_data_structs.py
new file mode 100755
index 000000000..9941cd190
--- /dev/null
+++ b/tools/lib/python/kdoc/parse_data_structs.py
@@ -0,0 +1,498 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2016-2025 by Mauro Carvalho Chehab <mchehab@kernel.org>.
+# pylint: disable=R0912,R0915
+
+"""
+Parse a source file or header, creating ReStructured Text cross references.
+
+It accepts an optional file to change the default symbol reference or to
+suppress symbols from the output.
+
+It is capable of identifying ``define``, function, ``struct``, ``typedef``,
+``enum`` and ``enum`` symbols and create cross-references for all of them.
+It is also capable of distinguish #define used for specifying a Linux
+ioctl.
+
+The optional rules file contains a set of rules like::
+
+    ignore ioctl VIDIOC_ENUM_FMT
+    replace ioctl VIDIOC_DQBUF vidioc_qbuf
+    replace define V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ :c:type:`v4l2_event_motion_det`
+"""
+
+import os
+import re
+import sys
+
+
+class ParseDataStructs:
+    """
+    Creates an enriched version of a Kernel header file with cross-links
+    to each C data structure type.
+
+    It is meant to allow having a more comprehensive documentation, where
+    uAPI headers will create cross-reference links to the code.
+
+    It is capable of identifying ``define``, function, ``struct``, ``typedef``,
+    ``enum`` and ``enum`` symbols and create cross-references for all of them.
+    It is also capable of distinguish #define used for specifying a Linux
+    ioctl.
+
+    By default, it create rules for all symbols and defines, but it also
+    allows parsing an exception file. Such file contains a set of rules
+    using the syntax below:
+
+    1. Ignore rules::
+
+        ignore <type> <symbol>`
+
+    Removes the symbol from reference generation.
+
+    2. Replace rules::
+
+        replace <type> <old_symbol> <new_reference>
+
+       Replaces how old_symbol with a new reference. The new_reference can be:
+
+        - A simple symbol name;
+        - A full Sphinx reference.
+
+    3. Namespace rules::
+
+        namespace <namespace>
+
+       Sets C namespace to be used during cross-reference generation. Can
+       be overridden by replace rules.
+
+    On ignore and replace rules, ``<type>`` can be:
+        - ``ioctl``: for defines that end with ``_IO*``, e.g. ioctl definitions
+        - ``define``: for other defines
+        - ``symbol``: for symbols defined within enums;
+        - ``typedef``: for typedefs;
+        - ``enum``: for the name of a non-anonymous enum;
+        - ``struct``: for structs.
+
+    Examples::
+
+        ignore define __LINUX_MEDIA_H
+        ignore ioctl VIDIOC_ENUM_FMT
+        replace ioctl VIDIOC_DQBUF vidioc_qbuf
+        replace define V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ :c:type:`v4l2_event_motion_det`
+
+        namespace MC
+    """
+
+    #: Parser regex with multiple ways to capture enums.
+    RE_ENUMS = [
+        re.compile(r"^\s*enum\s+([\w_]+)\s*\{"),
+        re.compile(r"^\s*enum\s+([\w_]+)\s*$"),
+        re.compile(r"^\s*typedef\s*enum\s+([\w_]+)\s*\{"),
+        re.compile(r"^\s*typedef\s*enum\s+([\w_]+)\s*$"),
+    ]
+
+    #: Parser regex with multiple ways to capture structs.
+    RE_STRUCTS = [
+        re.compile(r"^\s*struct\s+([_\w][\w\d_]+)\s*\{"),
+        re.compile(r"^\s*struct\s+([_\w][\w\d_]+)$"),
+        re.compile(r"^\s*typedef\s*struct\s+([_\w][\w\d_]+)\s*\{"),
+        re.compile(r"^\s*typedef\s*struct\s+([_\w][\w\d_]+)$"),
+    ]
+
+    # NOTE: the original code was written a long time before Sphinx C
+    # domain to have multiple namespaces. To avoid to much turn at the
+    # existing hyperlinks, the code kept using "c:type" instead of the
+    # right types. To change that, we need to change the types not only
+    # here, but also at the uAPI media documentation.
+
+    #: Dictionary containing C type identifiers to be transformed.
+    DEF_SYMBOL_TYPES = {
+        "ioctl": {
+            "prefix": "\\ ",
+            "suffix": "\\ ",
+            "ref_type": ":ref",
+            "description": "IOCTL Commands",
+        },
+        "define": {
+            "prefix": "\\ ",
+            "suffix": "\\ ",
+            "ref_type": ":ref",
+            "description": "Macros and Definitions",
+        },
+        # We're calling each definition inside an enum as "symbol"
+        "symbol": {
+            "prefix": "\\ ",
+            "suffix": "\\ ",
+            "ref_type": ":ref",
+            "description": "Enumeration values",
+        },
+        "typedef": {
+            "prefix": "\\ ",
+            "suffix": "\\ ",
+            "ref_type": ":c:type",
+            "description": "Type Definitions",
+        },
+        # This is the description of the enum itself
+        "enum": {
+            "prefix": "\\ ",
+            "suffix": "\\ ",
+            "ref_type": ":c:type",
+            "description": "Enumerations",
+        },
+        "struct": {
+            "prefix": "\\ ",
+            "suffix": "\\ ",
+            "ref_type": ":c:type",
+            "description": "Structures",
+        },
+    }
+
+    def __init__(self, debug: bool = False):
+        """Initialize internal vars"""
+        self.debug = debug
+        self.data = ""
+
+        self.symbols = {}
+
+        self.namespace = None
+        self.ignore = []
+        self.replace = []
+
+        for symbol_type in self.DEF_SYMBOL_TYPES:
+            self.symbols[symbol_type] = {}
+
+    def read_exceptions(self, fname: str):
+        """
+        Read an optional exceptions file, used to override defaults.
+        """
+
+        if not fname:
+            return
+
+        name = os.path.basename(fname)
+
+        with open(fname, "r", encoding="utf-8", errors="backslashreplace") as f:
+            for ln, line in enumerate(f):
+                ln += 1
+                line = line.strip()
+                if not line or line.startswith("#"):
+                    continue
+
+                # ignore rules
+                match = re.match(r"^ignore\s+(\w+)\s+(\S+)", line)
+
+                if match:
+                    self.ignore.append((ln, match.group(1), match.group(2)))
+                    continue
+
+                # replace rules
+                match = re.match(r"^replace\s+(\S+)\s+(\S+)\s+(\S+)", line)
+                if match:
+                    self.replace.append((ln, match.group(1), match.group(2),
+                                         match.group(3)))
+                    continue
+
+                match = re.match(r"^namespace\s+(\S+)", line)
+                if match:
+                    self.namespace = match.group(1)
+                    continue
+
+                sys.exit(f"{name}:{ln}: invalid line: {line}")
+
+    def apply_exceptions(self):
+        """
+        Process exceptions file with rules to ignore or replace references.
+        """
+
+        # Handle ignore rules
+        for ln, c_type, symbol in self.ignore:
+            if c_type not in self.DEF_SYMBOL_TYPES:
+                sys.exit(f"{name}:{ln}: {c_type} is invalid")
+
+            d = self.symbols[c_type]
+            if symbol in d:
+                del d[symbol]
+
+        # Handle replace rules
+        for ln, c_type, old, new in self.replace:
+            if c_type not in self.DEF_SYMBOL_TYPES:
+                sys.exit(f"{name}:{ln}: {c_type} is invalid")
+
+            reftype = None
+
+            # Parse reference type when the type is specified
+
+            match = re.match(r"^\:c\:(\w+)\:\`(.+)\`", new)
+            if match:
+                reftype = f":c:{match.group(1)}"
+                new = match.group(2)
+            else:
+                match = re.search(r"(\:ref)\:\`(.+)\`", new)
+                if match:
+                    reftype = match.group(1)
+                    new = match.group(2)
+
+            # If the replacement rule doesn't have a type, get default
+            if not reftype:
+                reftype = self.DEF_SYMBOL_TYPES[c_type].get("ref_type")
+                if not reftype:
+                    reftype = self.DEF_SYMBOL_TYPES[c_type].get("real_type")
+
+            new_ref = f"{reftype}:`{old} <{new}>`"
+
+            # Change self.symbols to use the replacement rule
+            if old in self.symbols[c_type]:
+                (_, ln) = self.symbols[c_type][old]
+                self.symbols[c_type][old] = (new_ref, ln)
+            else:
+                print(f"{name}:{ln}: Warning: can't find {old} {c_type}")
+
+    def store_type(self, ln, symbol_type: str, symbol: str,
+                   ref_name: str = None, replace_underscores: bool = True):
+        """
+        Store a new symbol at self.symbols under symbol_type.
+
+        By default, underscores are replaced by ``-``.
+        """
+        defs = self.DEF_SYMBOL_TYPES[symbol_type]
+
+        prefix = defs.get("prefix", "")
+        suffix = defs.get("suffix", "")
+        ref_type = defs.get("ref_type")
+
+        # Determine ref_link based on symbol type
+        if ref_type or self.namespace:
+            if not ref_name:
+                ref_name = symbol.lower()
+
+            # c-type references don't support hash
+            if ref_type == ":ref" and replace_underscores:
+                ref_name = ref_name.replace("_", "-")
+
+            # C domain references may have namespaces
+            if ref_type.startswith(":c:"):
+                if self.namespace:
+                    ref_name = f"{self.namespace}.{ref_name}"
+
+            if ref_type:
+                ref_link = f"{ref_type}:`{symbol} <{ref_name}>`"
+            else:
+                ref_link = f"`{symbol} <{ref_name}>`"
+        else:
+            ref_link = symbol
+
+        self.symbols[symbol_type][symbol] = (f"{prefix}{ref_link}{suffix}", ln)
+
+    def store_line(self, line):
+        """
+        Store a line at self.data, properly indented.
+        """
+        line = "    " + line.expandtabs()
+        self.data += line.rstrip(" ")
+
+    def parse_file(self, file_in: str, exceptions: str = None):
+        """
+        Read a C source file and get identifiers.
+        """
+        self.data = ""
+        is_enum = False
+        is_comment = False
+        multiline = ""
+
+        self.read_exceptions(exceptions)
+
+        with open(file_in, "r",
+                  encoding="utf-8", errors="backslashreplace") as f:
+            for line_no, line in enumerate(f):
+                self.store_line(line)
+                line = line.strip("\n")
+
+                # Handle continuation lines
+                if line.endswith(r"\\"):
+                    multiline += line[-1]
+                    continue
+
+                if multiline:
+                    line = multiline + line
+                    multiline = ""
+
+                # Handle comments. They can be multilined
+                if not is_comment:
+                    if re.search(r"/\*.*", line):
+                        is_comment = True
+                    else:
+                        # Strip C99-style comments
+                        line = re.sub(r"(//.*)", "", line)
+
+                if is_comment:
+                    if re.search(r".*\*/", line):
+                        is_comment = False
+                    else:
+                        multiline = line
+                        continue
+
+                # At this point, line variable may be a multilined statement,
+                # if lines end with \ or if they have multi-line comments
+                # With that, it can safely remove the entire comments,
+                # and there's no need to use re.DOTALL for the logic below
+
+                line = re.sub(r"(/\*.*\*/)", "", line)
+                if not line.strip():
+                    continue
+
+                # It can be useful for debug purposes to print the file after
+                # having comments stripped and multi-lines grouped.
+                if self.debug > 1:
+                    print(f"line {line_no + 1}: {line}")
+
+                # Now the fun begins: parse each type and store it.
+
+                # We opted for a two parsing logic here due to:
+                # 1. it makes easier to debug issues not-parsed symbols;
+                # 2. we want symbol replacement at the entire content, not
+                #    just when the symbol is detected.
+
+                if is_enum:
+                    match = re.match(r"^\s*([_\w][\w\d_]+)\s*[\,=]?", line)
+                    if match:
+                        self.store_type(line_no, "symbol", match.group(1))
+                    if "}" in line:
+                        is_enum = False
+                    continue
+
+                match = re.match(r"^\s*#\s*define\s+([\w_]+)\s+_IO", line)
+                if match:
+                    self.store_type(line_no, "ioctl", match.group(1),
+                                    replace_underscores=False)
+                    continue
+
+                match = re.match(r"^\s*#\s*define\s+([\w_]+)(\s+|$)", line)
+                if match:
+                    self.store_type(line_no, "define", match.group(1))
+                    continue
+
+                match = re.match(r"^\s*typedef\s+([_\w][\w\d_]+)\s+(.*)\s+([_\w][\w\d_]+);",
+                                 line)
+                if match:
+                    name = match.group(2).strip()
+                    symbol = match.group(3)
+                    self.store_type(line_no, "typedef", symbol, ref_name=name)
+                    continue
+
+                for re_enum in self.RE_ENUMS:
+                    match = re_enum.match(line)
+                    if match:
+                        self.store_type(line_no, "enum", match.group(1))
+                        is_enum = True
+                        break
+
+                for re_struct in self.RE_STRUCTS:
+                    match = re_struct.match(line)
+                    if match:
+                        self.store_type(line_no, "struct", match.group(1))
+                        break
+
+        self.apply_exceptions()
+
+    def debug_print(self):
+        """
+        Print debug information containing the replacement rules per symbol.
+        To make easier to check, group them per type.
+        """
+        if not self.debug:
+            return
+
+        for c_type, refs in self.symbols.items():
+            if not refs:  # Skip empty dictionaries
+                continue
+
+            print(f"{c_type}:")
+
+            for symbol, (ref, ln) in sorted(refs.items()):
+                print(f"  #{ln:<5d} {symbol} -> {ref}")
+
+            print()
+
+    def gen_output(self):
+        """Write the formatted output to a file."""
+
+        # Avoid extra blank lines
+        text = re.sub(r"\s+$", "", self.data) + "\n"
+        text = re.sub(r"\n\s+\n", "\n\n", text)
+
+        # Escape Sphinx special characters
+        text = re.sub(r"([\_\`\*\<\>\&\\\\:\/\|\%\$\#\{\}\~\^])", r"\\\1", text)
+
+        # Source uAPI files may have special notes. Use bold font for them
+        text = re.sub(r"DEPRECATED", "**DEPRECATED**", text)
+
+        # Delimiters to catch the entire symbol after escaped
+        start_delim = r"([ \n\t\(=\*\@])"
+        end_delim = r"(\s|,|\\=|\\:|\;|\)|\}|\{)"
+
+        # Process all reference types
+        for ref_dict in self.symbols.values():
+            for symbol, (replacement, _) in ref_dict.items():
+                symbol = re.escape(re.sub(r"([\_\`\*\<\>\&\\\\:\/])", r"\\\1", symbol))
+                text = re.sub(fr'{start_delim}{symbol}{end_delim}',
+                              fr'\1{replacement}\2', text)
+
+        # Remove "\ " where not needed: before spaces and at the end of lines
+        text = re.sub(r"\\ ([\n ])", r"\1", text)
+        text = re.sub(r" \\ ", " ", text)
+
+        return text
+
+    def gen_toc(self):
+        """
+        Create a list of symbols to be part of a TOC contents table.
+        """
+        text = []
+
+        # Sort symbol types per description
+        symbol_descriptions = []
+        for k, v in self.DEF_SYMBOL_TYPES.items():
+            symbol_descriptions.append((v['description'], k))
+
+        symbol_descriptions.sort()
+
+        # Process each category
+        for description, c_type in symbol_descriptions:
+
+            refs = self.symbols[c_type]
+            if not refs:  # Skip empty categories
+                continue
+
+            text.append(f"{description}")
+            text.append("-" * len(description))
+            text.append("")
+
+            # Sort symbols alphabetically
+            for symbol, (ref, ln) in sorted(refs.items()):
+                text.append(f"- LINENO_{ln}: {ref}")
+
+            text.append("")  # Add empty line between categories
+
+        return "\n".join(text)
+
+    def write_output(self, file_in: str, file_out: str, toc: bool):
+        """
+        Write a ReST output file.
+        """
+
+        title = os.path.basename(file_in)
+
+        if toc:
+            text = self.gen_toc()
+        else:
+            text = self.gen_output()
+
+        with open(file_out, "w", encoding="utf-8", errors="backslashreplace") as f:
+            f.write(".. -*- coding: utf-8; mode: rst -*-\n\n")
+            f.write(f"{title}\n")
+            f.write("=" * len(title) + "\n\n")
+
+            if not toc:
+                f.write(".. parsed-literal::\n\n")
+
+            f.write(text)
diff --git a/tools/lib/python/kdoc/python_version.py b/tools/lib/python/kdoc/python_version.py
new file mode 100644
index 000000000..4ddb7ead5
--- /dev/null
+++ b/tools/lib/python/kdoc/python_version.py
@@ -0,0 +1,190 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2017-2025 Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
+
+"""
+Handle Python version check logic.
+
+Not all Python versions are supported by scripts. Yet, on some cases,
+like during documentation build, a newer version of python could be
+available.
+
+This class allows checking if the minimal requirements are followed.
+
+Better than that, PythonVersion.check_python() not only checks the minimal
+requirements, but it automatically switches to a the newest available
+Python version if present.
+
+"""
+
+import os
+import re
+import subprocess
+import shlex
+import sys
+
+from glob import glob
+from textwrap import indent
+
+class PythonVersion:
+    """
+    Ancillary methods that checks for missing dependencies for different
+    types of types, like binaries, python modules, rpm deps, etc.
+    """
+
+    def __init__(self, version):
+        """
+        Ïnitialize self.version tuple from a version string.
+        """
+        self.version = self.parse_version(version)
+
+    @staticmethod
+    def parse_version(version):
+        """
+        Convert a major.minor.patch version into a tuple.
+        """
+        return tuple(int(x) for x in version.split("."))
+
+    @staticmethod
+    def ver_str(version):
+        """
+        Returns a version tuple as major.minor.patch.
+        """
+        return ".".join([str(x) for x in version])
+
+    @staticmethod
+    def cmd_print(cmd, max_len=80):
+        """
+        Outputs a command line, repecting maximum width.
+        """
+
+        cmd_line = []
+
+        for w in cmd:
+            w = shlex.quote(w)
+
+            if cmd_line:
+                if not max_len or len(cmd_line[-1]) + len(w) < max_len:
+                    cmd_line[-1] += " " + w
+                    continue
+                else:
+                    cmd_line[-1] += " \\"
+                    cmd_line.append(w)
+            else:
+                cmd_line.append(w)
+
+        return "\n  ".join(cmd_line)
+
+    def __str__(self):
+        """
+        Return a version tuple as major.minor.patch from self.version.
+        """
+        return self.ver_str(self.version)
+
+    @staticmethod
+    def get_python_version(cmd):
+        """
+        Get python version from a Python binary. As we need to detect if
+        are out there newer python binaries, we can't rely on sys.release here.
+        """
+
+        kwargs = {}
+        if sys.version_info < (3, 7):
+            kwargs['universal_newlines'] = True
+        else:
+            kwargs['text'] = True
+
+        result = subprocess.run([cmd, "--version"],
+                                stdout = subprocess.PIPE,
+                                stderr = subprocess.PIPE,
+                                **kwargs, check=False)
+
+        version = result.stdout.strip()
+
+        match = re.search(r"(\d+\.\d+\.\d+)", version)
+        if match:
+            return PythonVersion.parse_version(match.group(1))
+
+        print(f"Can't parse version {version}")
+        return (0, 0, 0)
+
+    @staticmethod
+    def find_python(min_version):
+        """
+        Detect if are out there any python 3.xy version newer than the
+        current one.
+
+        Note: this routine is limited to up to 2 digits for python3. We
+        may need to update it one day, hopefully on a distant future.
+        """
+        patterns = [
+            "python3.[0-9][0-9]",
+            "python3.[0-9]",
+        ]
+
+        python_cmd = []
+
+        # Seek for a python binary newer than min_version
+        for path in os.getenv("PATH", "").split(":"):
+            for pattern in patterns:
+                for cmd in glob(os.path.join(path, pattern)):
+                    if os.path.isfile(cmd) and os.access(cmd, os.X_OK):
+                        version = PythonVersion.get_python_version(cmd)
+                        if version >= min_version:
+                            python_cmd.append((version, cmd))
+
+        return sorted(python_cmd, reverse=True)
+
+    @staticmethod
+    def check_python(min_version, show_alternatives=False, bail_out=False,
+                     success_on_error=False):
+        """
+        Check if the current python binary satisfies our minimal requirement
+        for Sphinx build. If not, re-run with a newer version if found.
+        """
+        cur_ver = sys.version_info[:3]
+        if cur_ver >= min_version:
+            ver = PythonVersion.ver_str(cur_ver)
+            return
+
+        python_ver = PythonVersion.ver_str(cur_ver)
+
+        available_versions = PythonVersion.find_python(min_version)
+        if not available_versions:
+            print(f"ERROR: Python version {python_ver} is not supported anymore\n")
+            print("       Can't find a new version. This script may fail")
+            return
+
+        script_path = os.path.abspath(sys.argv[0])
+
+        # Check possible alternatives
+        if available_versions:
+            new_python_cmd = available_versions[0][1]
+        else:
+            new_python_cmd = None
+
+        if show_alternatives and available_versions:
+            print("You could run, instead:")
+            for _, cmd in available_versions:
+                args = [cmd, script_path] + sys.argv[1:]
+
+                cmd_str = indent(PythonVersion.cmd_print(args), "  ")
+                print(f"{cmd_str}\n")
+
+        if bail_out:
+            msg = f"Python {python_ver} not supported. Bailing out"
+            if success_on_error:
+                print(msg, file=sys.stderr)
+                sys.exit(0)
+            else:
+                sys.exit(msg)
+
+        print(f"Python {python_ver} not supported. Changing to {new_python_cmd}")
+
+        # Restart script using the newer version
+        args = [new_python_cmd, script_path] + sys.argv[1:]
+
+        try:
+            os.execv(new_python_cmd, args)
+        except OSError as e:
+            sys.exit(f"Failed to restart with {new_python_cmd}: {e}")
diff --git a/tools/lib/python/kdoc/xforms_lists.py b/tools/lib/python/kdoc/xforms_lists.py
new file mode 100644
index 000000000..e3dda2fe8
--- /dev/null
+++ b/tools/lib/python/kdoc/xforms_lists.py
@@ -0,0 +1,160 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2026: Mauro Carvalho Chehab <mchehab@kernel.org>.
+
+import re
+
+from kdoc.kdoc_re import KernRe
+from kdoc.c_lex import CMatch, CTokenizer
+
+struct_args_pattern = r"([^,)]+)"
+
+
+class CTransforms:
+    """
+    Data class containing a long set of transformations to turn
+    structure member prefixes, and macro invocations and variables
+    into something we can parse and generate kdoc for.
+    """
+
+    #
+    # NOTE:
+    #      Due to performance reasons, place CMatch rules before KernRe,
+    #      as this avoids running the C parser every time.
+    #
+
+    #: Transforms for structs and unions.
+    struct_xforms = [
+        (CMatch("__attribute__"), ""),
+        (CMatch("__aligned"), ""),
+        (CMatch("__counted_by"), ""),
+        (CMatch("__counted_by_(le|be)"), ""),
+        (CMatch("__counted_by_ptr"), ""),
+        (CMatch("__guarded_by"), ""),
+        (CMatch("__pt_guarded_by"), ""),
+        (CMatch("__packed"), ""),
+        (CMatch("CRYPTO_MINALIGN_ATTR"), ""),
+        (CMatch("__private"), ""),
+        (CMatch("__rcu"), ""),
+        (CMatch("____cacheline_aligned_in_smp"), ""),
+        (CMatch("____cacheline_aligned"), ""),
+        (CMatch("__cacheline_group_(?:begin|end)"), ""),
+        (CMatch("__ETHTOOL_DECLARE_LINK_MODE_MASK"), r"DECLARE_BITMAP(\1, __ETHTOOL_LINK_MODE_MASK_NBITS)"),
+        (CMatch("DECLARE_PHY_INTERFACE_MASK",),r"DECLARE_BITMAP(\1, PHY_INTERFACE_MODE_MAX)"),
+        (CMatch("DECLARE_BITMAP"), r"unsigned long \1[BITS_TO_LONGS(\2)]"),
+        (CMatch("DECLARE_HASHTABLE"), r"unsigned long \1[1 << ((\2) - 1)]"),
+        (CMatch("DECLARE_KFIFO"), r"\2 *\1"),
+        (CMatch("DECLARE_KFIFO_PTR"), r"\2 *\1"),
+        (CMatch("(?:__)?DECLARE_FLEX_ARRAY"), r"\1 \2[]"),
+        (CMatch("DEFINE_DMA_UNMAP_ADDR"), r"dma_addr_t \1"),
+        (CMatch("DEFINE_DMA_UNMAP_LEN"), r"__u32 \1"),
+        (CMatch("VIRTIO_DECLARE_FEATURES"), r"union { u64 \1; u64 \1_array[VIRTIO_FEATURES_U64S]; }"),
+        (CMatch("__SYSFS_FUNCTION_ALTERNATIVE"), r"union { \1+ }"),
+        (CMatch("__attribute__"), ""),
+
+        #
+        # Macro __struct_group() creates an union with an anonymous
+        # and a non-anonymous struct, depending on the parameters. We only
+        # need one of those at kernel-doc, as we won't be documenting the same
+        # members twice.
+        #
+        (CMatch("struct_group"), r"struct { \2+ };"),
+        (CMatch("struct_group_attr"), r"struct { \3+ };"),
+        (CMatch("struct_group_tagged"), r"struct { \3+ };"),
+        (CMatch("__struct_group"), r"struct { \4+ };"),
+    ]
+
+    #: Transforms for function prototypes.
+    function_xforms = [
+        (CMatch("static"), ""),
+        (CMatch("extern"), ""),
+        (CMatch("asmlinkage"), ""),
+        (CMatch("inline"), ""),
+        (CMatch("__inline__"), ""),
+        (CMatch("__inline"), ""),
+        (CMatch("__always_inline"), ""),
+        (CMatch("noinline"), ""),
+        (CMatch("__FORTIFY_INLINE"), ""),
+        (CMatch("__init"), ""),
+        (CMatch("__init_or_module"), ""),
+        (CMatch("__exit"), ""),
+        (CMatch("__deprecated"), ""),
+        (CMatch("__flatten"), ""),
+        (CMatch("__meminit"), ""),
+        (CMatch("__must_check"), ""),
+        (CMatch("__weak"), ""),
+        (CMatch("__sched"), ""),
+        (CMatch("__always_unused"), ""),
+        (CMatch("__maybe_unused"), ""),
+        (CMatch("__printf"), ""),
+        (CMatch("__(?:re)?alloc_size"), ""),
+        (CMatch("__diagnose_as"), ""),
+        (CMatch("DECL_BUCKET_PARAMS"), r"\1, \2"),
+        (CMatch("DEFINE_IDTENTRY_IRQ"), r"static void \1(struct pt_regs *regs, u32 vector)"),
+        (CMatch("__cond_acquires"), ""),
+        (CMatch("__cond_releases"), ""),
+        (CMatch("__acquires"), ""),
+        (CMatch("__releases"), ""),
+        (CMatch("__must_hold"), ""),
+        (CMatch("__must_not_hold"), ""),
+        (CMatch("__must_hold_shared"), ""),
+        (CMatch("__cond_acquires_shared"), ""),
+        (CMatch("__acquires_shared"), ""),
+        (CMatch("__releases_shared"), ""),
+        (CMatch("__no_context_analysis"), ""),
+        (CMatch("__attribute_const__"), ""),
+        (CMatch("__attribute__"), ""),
+        (CMatch("STATIC_IFN_KUNIT"), ""),
+        (CMatch("INLINE_IFN_KUNIT"), ""),
+
+        #
+        # HACK: this is similar to process_export() hack. It is meant to
+        # drop _noproof from function name. See for instance:
+        # ahash_request_alloc kernel-doc declaration at include/crypto/hash.h.
+        #
+        (KernRe("_noprof"), ""),
+    ]
+
+    #: Transforms for variable prototypes.
+    var_xforms = [
+        (CMatch("__read_mostly"), ""),
+        (CMatch("__ro_after_init"), ""),
+        (CMatch("__guarded_by"), ""),
+        (CMatch("__pt_guarded_by"), ""),
+        (CMatch("LIST_HEAD"), r"struct list_head \1"),
+        (CMatch("DECLARE_PER_CPU"), r"\1 \2[PER_CPU]; }"),
+
+        (KernRe(r"(?://.*)$"), ""),
+        (KernRe(r"(?:/\*.*\*/)"), ""),
+        (KernRe(r";$"), ""),
+    ]
+
+    #: Transforms main dictionary used at apply_transforms().
+    xforms = {
+        "struct": struct_xforms,
+        "func": function_xforms,
+        "var": var_xforms,
+    }
+
+    def apply(self, xforms_type, source):
+        """
+        Apply a set of transforms to a block of source.
+
+        As tokenizer is used here, this function also remove comments
+        at the end.
+        """
+        if xforms_type not in self.xforms:
+            return source
+
+        if isinstance(source, str):
+            source = CTokenizer(source)
+
+        for search, subst in self.xforms[xforms_type]:
+            #
+            # KernRe only accept strings.
+            #
+            if isinstance(search, KernRe):
+                source = str(source)
+
+            source = search.sub(subst, source)
+        return str(source)
diff --git a/tools/lib/python/unittest_helper.py b/tools/lib/python/unittest_helper.py
new file mode 100755
index 000000000..f3cba5120
--- /dev/null
+++ b/tools/lib/python/unittest_helper.py
@@ -0,0 +1,363 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright(c) 2025-2026: Mauro Carvalho Chehab <mchehab@kernel.org>.
+#
+# pylint: disable=C0103,R0912,R0914,E1101
+
+"""
+Provides helper functions and classes execute python unit tests.
+
+Those help functions provide a nice colored output summary of each
+executed test and, when a test fails, it shows the different in diff
+format when running in verbose mode, like::
+
+    $ tools/unittests/nested_match.py -v
+    ...
+    Traceback (most recent call last):
+    File "/new_devel/docs/tools/unittests/nested_match.py", line 69, in test_count_limit
+        self.assertEqual(replaced, "bar(a); bar(b); foo(c)")
+        ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    AssertionError: 'bar(a) foo(b); foo(c)' != 'bar(a); bar(b); foo(c)'
+    - bar(a) foo(b); foo(c)
+    ?       ^^^^
+    + bar(a); bar(b); foo(c)
+    ?       ^^^^^
+    ...
+
+It also allows filtering what tests will be executed via ``-k`` parameter.
+
+Typical usage is to do::
+
+    from unittest_helper import run_unittest
+    ...
+
+    if __name__ == "__main__":
+        run_unittest(__file__)
+
+If passing arguments is needed, on a more complex scenario, it can be
+used like on this example::
+
+    from unittest_helper import TestUnits, run_unittest
+    ...
+    env = {'sudo': ""}
+    ...
+    if __name__ == "__main__":
+        runner = TestUnits()
+        base_parser = runner.parse_args()
+        base_parser.add_argument('--sudo', action='store_true',
+                                help='Enable tests requiring sudo privileges')
+
+        args = base_parser.parse_args()
+
+        # Update module-level flag
+        if args.sudo:
+            env['sudo'] = "1"
+
+        # Run tests with customized arguments
+        runner.run(__file__, parser=base_parser, args=args, env=env)
+"""
+
+import argparse
+import atexit
+import os
+import re
+import unittest
+import sys
+
+from unittest.mock import patch
+
+
+class Summary(unittest.TestResult):
+    """
+    Overrides ``unittest.TestResult`` class to provide a nice colored
+    summary. When in verbose mode, displays actual/expected difference in
+    unified diff format.
+    """
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        #: Dictionary to store organized test results.
+        self.test_results = {}
+
+        #: max length of the test names.
+        self.max_name_length = 0
+
+    def startTest(self, test):
+        super().startTest(test)
+        test_id = test.id()
+        parts = test_id.split(".")
+
+        # Extract module, class, and method names
+        if len(parts) >= 3:
+            module_name = parts[-3]
+        else:
+            module_name = ""
+        if len(parts) >= 2:
+            class_name = parts[-2]
+        else:
+            class_name = ""
+
+        method_name = parts[-1]
+
+        # Build the hierarchical structure
+        if module_name not in self.test_results:
+            self.test_results[module_name] = {}
+
+        if class_name not in self.test_results[module_name]:
+            self.test_results[module_name][class_name] = []
+
+        # Track maximum test name length for alignment
+        display_name = f"{method_name}:"
+
+        self.max_name_length = max(len(display_name), self.max_name_length)
+
+    def _record_test(self, test, status):
+        test_id = test.id()
+        parts = test_id.split(".")
+        if len(parts) >= 3:
+            module_name = parts[-3]
+        else:
+            module_name = ""
+        if len(parts) >= 2:
+            class_name = parts[-2]
+        else:
+            class_name = ""
+        method_name = parts[-1]
+        self.test_results[module_name][class_name].append((method_name, status))
+
+    def addSuccess(self, test):
+        super().addSuccess(test)
+        self._record_test(test, "OK")
+
+    def addFailure(self, test, err):
+        super().addFailure(test, err)
+        self._record_test(test, "FAIL")
+
+    def addError(self, test, err):
+        super().addError(test, err)
+        self._record_test(test, "ERROR")
+
+    def addSkip(self, test, reason):
+        super().addSkip(test, reason)
+        self._record_test(test, f"SKIP ({reason})")
+
+    def printResults(self, verbose):
+        """
+        Print results using colors if tty.
+        """
+        # Check for ANSI color support
+        use_color = sys.stdout.isatty()
+        COLORS = {
+            "OK":            "\033[32m",   # Green
+            "FAIL":          "\033[31m",   # Red
+            "SKIP":          "\033[1;33m", # Yellow
+            "PARTIAL":       "\033[33m",   # Orange
+            "EXPECTED_FAIL": "\033[36m",   # Cyan
+            "reset":         "\033[0m",    # Reset to default terminal color
+        }
+        if not use_color:
+            for c in COLORS:
+                COLORS[c] = ""
+
+        # Calculate maximum test name length
+        if not self.test_results:
+            return
+        try:
+            lengths = []
+            for module in self.test_results.values():
+                for tests in module.values():
+                    for test_name, _ in tests:
+                        lengths.append(len(test_name) + 1)  # +1 for colon
+            max_length = max(lengths) + 2  # Additional padding
+        except ValueError:
+            sys.exit("Test list is empty")
+
+        # Print results
+        for module_name, classes in self.test_results.items():
+            if verbose:
+                print(f"{module_name}:")
+            for class_name, tests in classes.items():
+                if verbose:
+                    print(f"    {class_name}:")
+                for test_name, status in tests:
+                    if not verbose and status in [ "OK", "EXPECTED_FAIL" ]:
+                        continue
+
+                    # Get base status without reason for SKIP
+                    if status.startswith("SKIP"):
+                        status_code = status.split()[0]
+                    else:
+                        status_code = status
+                    color = COLORS.get(status_code, "")
+                    print(
+                        f"        {test_name + ':':<{max_length}}{color}{status}{COLORS['reset']}"
+                    )
+            if verbose:
+                print()
+
+        # Print summary
+        print(f"\nRan {self.testsRun} tests", end="")
+        if hasattr(self, "timeTaken"):
+            print(f" in {self.timeTaken:.3f}s", end="")
+        print()
+
+        if not self.wasSuccessful():
+            print(f"\n{COLORS['FAIL']}FAILED (", end="")
+            failures = getattr(self, "failures", [])
+            errors = getattr(self, "errors", [])
+            if failures:
+                print(f"failures={len(failures)}", end="")
+            if errors:
+                if failures:
+                    print(", ", end="")
+                print(f"errors={len(errors)}", end="")
+            print(f"){COLORS['reset']}")
+
+
+def flatten_suite(suite):
+    """Flatten test suite hierarchy."""
+    tests = []
+    for item in suite:
+        if isinstance(item, unittest.TestSuite):
+            tests.extend(flatten_suite(item))
+        else:
+            tests.append(item)
+    return tests
+
+
+class TestUnits:
+    """
+    Helper class to set verbosity level.
+
+    This class discover test files, import its unittest classes and
+    executes the test on it.
+    """
+    def parse_args(self):
+        """Returns a parser for command line arguments."""
+        parser = argparse.ArgumentParser(description="Test runner with regex filtering")
+        parser.add_argument("-v", "--verbose", action="count", default=1)
+        parser.add_argument("-q", "--quiet", action="store_true")
+        parser.add_argument("-f", "--failfast", action="store_true")
+        parser.add_argument("-k", "--keyword",
+                            help="Regex pattern to filter test methods")
+        return parser
+
+    def run(self, caller_file=None, pattern=None,
+            suite=None, parser=None, args=None, env=None):
+        """
+        Execute all tests from the unity test file.
+
+        It contains several optional parameters:
+
+        ``caller_file``:
+            -  name of the file that contains test.
+
+               typical usage is to place __file__ at the caller test, e.g.::
+
+                    if __name__ == "__main__":
+                        TestUnits().run(__file__)
+
+        ``pattern``:
+            - optional pattern to match multiple file names. Defaults
+              to basename of ``caller_file``.
+
+        ``suite``:
+            - an unittest suite initialized by the caller using
+              ``unittest.TestLoader().discover()``.
+
+        ``parser``:
+            - an argparse parser. If not defined, this helper will create
+              one.
+
+        ``args``:
+            - an ``argparse.Namespace`` data filled by the caller.
+
+        ``env``:
+            - environment variables that will be passed to the test suite
+
+        At least ``caller_file`` or ``suite`` must be used, otherwise a
+        ``TypeError`` will be raised.
+        """
+        if not args:
+            if not parser:
+                parser = self.parse_args()
+            args = parser.parse_args()
+
+        if not caller_file and not suite:
+            raise TypeError("Either caller_file or suite is needed at TestUnits")
+
+        if args.quiet:
+            verbose = 0
+        else:
+            verbose = args.verbose
+
+        if not env:
+            env = os.environ.copy()
+
+        env["VERBOSE"] = f"{verbose}"
+
+        patcher = patch.dict(os.environ, env)
+        patcher.start()
+        # ensure it gets stopped after
+        atexit.register(patcher.stop)
+
+
+        if verbose >= 2:
+            unittest.TextTestRunner(verbosity=verbose).run = lambda suite: suite
+
+        # Load ONLY tests from the calling file
+        if not suite:
+            if not pattern:
+                pattern = caller_file
+
+            loader = unittest.TestLoader()
+            suite = loader.discover(start_dir=os.path.dirname(caller_file),
+                                    pattern=os.path.basename(caller_file))
+
+        # Flatten the suite for environment injection
+        tests_to_inject = flatten_suite(suite)
+
+        # Filter tests by method name if -k specified
+        if args.keyword:
+            try:
+                pattern = re.compile(args.keyword)
+                filtered_suite = unittest.TestSuite()
+                for test in tests_to_inject:  # Use the pre-flattened list
+                    method_name = test.id().split(".")[-1]
+                    if pattern.search(method_name):
+                        filtered_suite.addTest(test)
+                suite = filtered_suite
+            except re.error as e:
+                sys.stderr.write(f"Invalid regex pattern: {e}\n")
+                sys.exit(1)
+        else:
+            # Maintain original suite structure if no keyword filtering
+            suite = unittest.TestSuite(tests_to_inject)
+
+        if verbose >= 2:
+            resultclass = None
+        else:
+            resultclass = Summary
+
+        runner = unittest.TextTestRunner(verbosity=args.verbose,
+                                            resultclass=resultclass,
+                                            failfast=args.failfast)
+        result = runner.run(suite)
+        if resultclass:
+            result.printResults(verbose)
+
+        sys.exit(not result.wasSuccessful())
+
+
+def run_unittest(fname):
+    """
+    Basic usage of TestUnits class.
+
+    Use it when there's no need to pass any extra argument to the tests
+    with. The recommended way is to place this at the end of each
+    unittest module::
+
+        if __name__ == "__main__":
+            run_unittest(__file__)
+    """
+    TestUnits().run(fname)
diff --git a/tools/lib/rbtree.c b/tools/lib/rbtree.c
new file mode 100644
index 000000000..9e7307186
--- /dev/null
+++ b/tools/lib/rbtree.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+  Red Black Trees
+  (C) 1999  Andrea Arcangeli <andrea@suse.de>
+  (C) 2002  David Woodhouse <dwmw2@infradead.org>
+  (C) 2012  Michel Lespinasse <walken@google.com>
+
+
+  linux/lib/rbtree.c
+*/
+
+#include <linux/rbtree_augmented.h>
+#include <linux/export.h>
+
+/*
+ * red-black trees properties:  https://en.wikipedia.org/wiki/Rbtree
+ *
+ *  1) A node is either red or black
+ *  2) The root is black
+ *  3) All leaves (NULL) are black
+ *  4) Both children of every red node are black
+ *  5) Every simple path from root to leaves contains the same number
+ *     of black nodes.
+ *
+ *  4 and 5 give the O(log n) guarantee, since 4 implies you cannot have two
+ *  consecutive red nodes in a path and every red node is therefore followed by
+ *  a black. So if B is the number of black nodes on every simple path (as per
+ *  5), then the longest possible path due to 4 is 2B.
+ *
+ *  We shall indicate color with case, where black nodes are uppercase and red
+ *  nodes will be lowercase. Unknown color nodes shall be drawn as red within
+ *  parentheses and have some accompanying text comment.
+ */
+
+/*
+ * Notes on lockless lookups:
+ *
+ * All stores to the tree structure (rb_left and rb_right) must be done using
+ * WRITE_ONCE(). And we must not inadvertently cause (temporary) loops in the
+ * tree structure as seen in program order.
+ *
+ * These two requirements will allow lockless iteration of the tree -- not
+ * correct iteration mind you, tree rotations are not atomic so a lookup might
+ * miss entire subtrees.
+ *
+ * But they do guarantee that any such traversal will only see valid elements
+ * and that it will indeed complete -- does not get stuck in a loop.
+ *
+ * It also guarantees that if the lookup returns an element it is the 'correct'
+ * one. But not returning an element does _NOT_ mean it's not present.
+ *
+ * NOTE:
+ *
+ * Stores to __rb_parent_color are not important for simple lookups so those
+ * are left undone as of now. Nor did I check for loops involving parent
+ * pointers.
+ */
+
+static inline void rb_set_black(struct rb_node *rb)
+{
+	rb->__rb_parent_color += RB_BLACK;
+}
+
+static inline struct rb_node *rb_red_parent(struct rb_node *red)
+{
+	return (struct rb_node *)red->__rb_parent_color;
+}
+
+/*
+ * Helper function for rotations:
+ * - old's parent and color get assigned to new
+ * - old gets assigned new as a parent and 'color' as a color.
+ */
+static inline void
+__rb_rotate_set_parents(struct rb_node *old, struct rb_node *new,
+			struct rb_root *root, int color)
+{
+	struct rb_node *parent = rb_parent(old);
+	new->__rb_parent_color = old->__rb_parent_color;
+	rb_set_parent_color(old, new, color);
+	__rb_change_child(old, new, parent, root);
+}
+
+static __always_inline void
+__rb_insert(struct rb_node *node, struct rb_root *root,
+	    void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+{
+	struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
+
+	while (true) {
+		/*
+		 * Loop invariant: node is red.
+		 */
+		if (unlikely(!parent)) {
+			/*
+			 * The inserted node is root. Either this is the
+			 * first node, or we recursed at Case 1 below and
+			 * are no longer violating 4).
+			 */
+			rb_set_parent_color(node, NULL, RB_BLACK);
+			break;
+		}
+
+		/*
+		 * If there is a black parent, we are done.
+		 * Otherwise, take some corrective action as,
+		 * per 4), we don't want a red root or two
+		 * consecutive red nodes.
+		 */
+		if(rb_is_black(parent))
+			break;
+
+		gparent = rb_red_parent(parent);
+
+		tmp = gparent->rb_right;
+		if (parent != tmp) {	/* parent == gparent->rb_left */
+			if (tmp && rb_is_red(tmp)) {
+				/*
+				 * Case 1 - node's uncle is red (color flips).
+				 *
+				 *       G            g
+				 *      / \          / \
+				 *     p   u  -->   P   U
+				 *    /            /
+				 *   n            n
+				 *
+				 * However, since g's parent might be red, and
+				 * 4) does not allow this, we need to recurse
+				 * at g.
+				 */
+				rb_set_parent_color(tmp, gparent, RB_BLACK);
+				rb_set_parent_color(parent, gparent, RB_BLACK);
+				node = gparent;
+				parent = rb_parent(node);
+				rb_set_parent_color(node, parent, RB_RED);
+				continue;
+			}
+
+			tmp = parent->rb_right;
+			if (node == tmp) {
+				/*
+				 * Case 2 - node's uncle is black and node is
+				 * the parent's right child (left rotate at parent).
+				 *
+				 *      G             G
+				 *     / \           / \
+				 *    p   U  -->    n   U
+				 *     \           /
+				 *      n         p
+				 *
+				 * This still leaves us in violation of 4), the
+				 * continuation into Case 3 will fix that.
+				 */
+				tmp = node->rb_left;
+				WRITE_ONCE(parent->rb_right, tmp);
+				WRITE_ONCE(node->rb_left, parent);
+				if (tmp)
+					rb_set_parent_color(tmp, parent,
+							    RB_BLACK);
+				rb_set_parent_color(parent, node, RB_RED);
+				augment_rotate(parent, node);
+				parent = node;
+				tmp = node->rb_right;
+			}
+
+			/*
+			 * Case 3 - node's uncle is black and node is
+			 * the parent's left child (right rotate at gparent).
+			 *
+			 *        G           P
+			 *       / \         / \
+			 *      p   U  -->  n   g
+			 *     /                 \
+			 *    n                   U
+			 */
+			WRITE_ONCE(gparent->rb_left, tmp); /* == parent->rb_right */
+			WRITE_ONCE(parent->rb_right, gparent);
+			if (tmp)
+				rb_set_parent_color(tmp, gparent, RB_BLACK);
+			__rb_rotate_set_parents(gparent, parent, root, RB_RED);
+			augment_rotate(gparent, parent);
+			break;
+		} else {
+			tmp = gparent->rb_left;
+			if (tmp && rb_is_red(tmp)) {
+				/* Case 1 - color flips */
+				rb_set_parent_color(tmp, gparent, RB_BLACK);
+				rb_set_parent_color(parent, gparent, RB_BLACK);
+				node = gparent;
+				parent = rb_parent(node);
+				rb_set_parent_color(node, parent, RB_RED);
+				continue;
+			}
+
+			tmp = parent->rb_left;
+			if (node == tmp) {
+				/* Case 2 - right rotate at parent */
+				tmp = node->rb_right;
+				WRITE_ONCE(parent->rb_left, tmp);
+				WRITE_ONCE(node->rb_right, parent);
+				if (tmp)
+					rb_set_parent_color(tmp, parent,
+							    RB_BLACK);
+				rb_set_parent_color(parent, node, RB_RED);
+				augment_rotate(parent, node);
+				parent = node;
+				tmp = node->rb_left;
+			}
+
+			/* Case 3 - left rotate at gparent */
+			WRITE_ONCE(gparent->rb_right, tmp); /* == parent->rb_left */
+			WRITE_ONCE(parent->rb_left, gparent);
+			if (tmp)
+				rb_set_parent_color(tmp, gparent, RB_BLACK);
+			__rb_rotate_set_parents(gparent, parent, root, RB_RED);
+			augment_rotate(gparent, parent);
+			break;
+		}
+	}
+}
+
+/*
+ * Inline version for rb_erase() use - we want to be able to inline
+ * and eliminate the dummy_rotate callback there
+ */
+static __always_inline void
+____rb_erase_color(struct rb_node *parent, struct rb_root *root,
+	void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+{
+	struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
+
+	while (true) {
+		/*
+		 * Loop invariants:
+		 * - node is black (or NULL on first iteration)
+		 * - node is not the root (parent is not NULL)
+		 * - All leaf paths going through parent and node have a
+		 *   black node count that is 1 lower than other leaf paths.
+		 */
+		sibling = parent->rb_right;
+		if (node != sibling) {	/* node == parent->rb_left */
+			if (rb_is_red(sibling)) {
+				/*
+				 * Case 1 - left rotate at parent
+				 *
+				 *     P               S
+				 *    / \             / \
+				 *   N   s    -->    p   Sr
+				 *      / \         / \
+				 *     Sl  Sr      N   Sl
+				 */
+				tmp1 = sibling->rb_left;
+				WRITE_ONCE(parent->rb_right, tmp1);
+				WRITE_ONCE(sibling->rb_left, parent);
+				rb_set_parent_color(tmp1, parent, RB_BLACK);
+				__rb_rotate_set_parents(parent, sibling, root,
+							RB_RED);
+				augment_rotate(parent, sibling);
+				sibling = tmp1;
+			}
+			tmp1 = sibling->rb_right;
+			if (!tmp1 || rb_is_black(tmp1)) {
+				tmp2 = sibling->rb_left;
+				if (!tmp2 || rb_is_black(tmp2)) {
+					/*
+					 * Case 2 - sibling color flip
+					 * (p could be either color here)
+					 *
+					 *    (p)           (p)
+					 *    / \           / \
+					 *   N   S    -->  N   s
+					 *      / \           / \
+					 *     Sl  Sr        Sl  Sr
+					 *
+					 * This leaves us violating 5) which
+					 * can be fixed by flipping p to black
+					 * if it was red, or by recursing at p.
+					 * p is red when coming from Case 1.
+					 */
+					rb_set_parent_color(sibling, parent,
+							    RB_RED);
+					if (rb_is_red(parent))
+						rb_set_black(parent);
+					else {
+						node = parent;
+						parent = rb_parent(node);
+						if (parent)
+							continue;
+					}
+					break;
+				}
+				/*
+				 * Case 3 - right rotate at sibling
+				 * (p could be either color here)
+				 *
+				 *   (p)           (p)
+				 *   / \           / \
+				 *  N   S    -->  N   sl
+				 *     / \             \
+				 *    sl  Sr            S
+				 *                       \
+				 *                        Sr
+				 *
+				 * Note: p might be red, and then both
+				 * p and sl are red after rotation(which
+				 * breaks property 4). This is fixed in
+				 * Case 4 (in __rb_rotate_set_parents()
+				 *         which set sl the color of p
+				 *         and set p RB_BLACK)
+				 *
+				 *   (p)            (sl)
+				 *   / \            /  \
+				 *  N   sl   -->   P    S
+				 *       \        /      \
+				 *        S      N        Sr
+				 *         \
+				 *          Sr
+				 */
+				tmp1 = tmp2->rb_right;
+				WRITE_ONCE(sibling->rb_left, tmp1);
+				WRITE_ONCE(tmp2->rb_right, sibling);
+				WRITE_ONCE(parent->rb_right, tmp2);
+				if (tmp1)
+					rb_set_parent_color(tmp1, sibling,
+							    RB_BLACK);
+				augment_rotate(sibling, tmp2);
+				tmp1 = sibling;
+				sibling = tmp2;
+			}
+			/*
+			 * Case 4 - left rotate at parent + color flips
+			 * (p and sl could be either color here.
+			 *  After rotation, p becomes black, s acquires
+			 *  p's color, and sl keeps its color)
+			 *
+			 *      (p)             (s)
+			 *      / \             / \
+			 *     N   S     -->   P   Sr
+			 *        / \         / \
+			 *      (sl) sr      N  (sl)
+			 */
+			tmp2 = sibling->rb_left;
+			WRITE_ONCE(parent->rb_right, tmp2);
+			WRITE_ONCE(sibling->rb_left, parent);
+			rb_set_parent_color(tmp1, sibling, RB_BLACK);
+			if (tmp2)
+				rb_set_parent(tmp2, parent);
+			__rb_rotate_set_parents(parent, sibling, root,
+						RB_BLACK);
+			augment_rotate(parent, sibling);
+			break;
+		} else {
+			sibling = parent->rb_left;
+			if (rb_is_red(sibling)) {
+				/* Case 1 - right rotate at parent */
+				tmp1 = sibling->rb_right;
+				WRITE_ONCE(parent->rb_left, tmp1);
+				WRITE_ONCE(sibling->rb_right, parent);
+				rb_set_parent_color(tmp1, parent, RB_BLACK);
+				__rb_rotate_set_parents(parent, sibling, root,
+							RB_RED);
+				augment_rotate(parent, sibling);
+				sibling = tmp1;
+			}
+			tmp1 = sibling->rb_left;
+			if (!tmp1 || rb_is_black(tmp1)) {
+				tmp2 = sibling->rb_right;
+				if (!tmp2 || rb_is_black(tmp2)) {
+					/* Case 2 - sibling color flip */
+					rb_set_parent_color(sibling, parent,
+							    RB_RED);
+					if (rb_is_red(parent))
+						rb_set_black(parent);
+					else {
+						node = parent;
+						parent = rb_parent(node);
+						if (parent)
+							continue;
+					}
+					break;
+				}
+				/* Case 3 - left rotate at sibling */
+				tmp1 = tmp2->rb_left;
+				WRITE_ONCE(sibling->rb_right, tmp1);
+				WRITE_ONCE(tmp2->rb_left, sibling);
+				WRITE_ONCE(parent->rb_left, tmp2);
+				if (tmp1)
+					rb_set_parent_color(tmp1, sibling,
+							    RB_BLACK);
+				augment_rotate(sibling, tmp2);
+				tmp1 = sibling;
+				sibling = tmp2;
+			}
+			/* Case 4 - right rotate at parent + color flips */
+			tmp2 = sibling->rb_right;
+			WRITE_ONCE(parent->rb_left, tmp2);
+			WRITE_ONCE(sibling->rb_right, parent);
+			rb_set_parent_color(tmp1, sibling, RB_BLACK);
+			if (tmp2)
+				rb_set_parent(tmp2, parent);
+			__rb_rotate_set_parents(parent, sibling, root,
+						RB_BLACK);
+			augment_rotate(parent, sibling);
+			break;
+		}
+	}
+}
+
+/* Non-inline version for rb_erase_augmented() use */
+void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
+	void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+{
+	____rb_erase_color(parent, root, augment_rotate);
+}
+
+/*
+ * Non-augmented rbtree manipulation functions.
+ *
+ * We use dummy augmented callbacks here, and have the compiler optimize them
+ * out of the rb_insert_color() and rb_erase() function definitions.
+ */
+
+static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {}
+static inline void dummy_copy(struct rb_node *old, struct rb_node *new) {}
+static inline void dummy_rotate(struct rb_node *old, struct rb_node *new) {}
+
+static const struct rb_augment_callbacks dummy_callbacks = {
+	.propagate = dummy_propagate,
+	.copy = dummy_copy,
+	.rotate = dummy_rotate
+};
+
+void rb_insert_color(struct rb_node *node, struct rb_root *root)
+{
+	__rb_insert(node, root, dummy_rotate);
+}
+
+void rb_erase(struct rb_node *node, struct rb_root *root)
+{
+	struct rb_node *rebalance;
+	rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
+	if (rebalance)
+		____rb_erase_color(rebalance, root, dummy_rotate);
+}
+
+/*
+ * Augmented rbtree manipulation functions.
+ *
+ * This instantiates the same __always_inline functions as in the non-augmented
+ * case, but this time with user-defined callbacks.
+ */
+
+void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
+	void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
+{
+	__rb_insert(node, root, augment_rotate);
+}
+
+/*
+ * This function returns the first node (in sort order) of the tree.
+ */
+struct rb_node *rb_first(const struct rb_root *root)
+{
+	struct rb_node	*n;
+
+	n = root->rb_node;
+	if (!n)
+		return NULL;
+	while (n->rb_left)
+		n = n->rb_left;
+	return n;
+}
+
+struct rb_node *rb_last(const struct rb_root *root)
+{
+	struct rb_node	*n;
+
+	n = root->rb_node;
+	if (!n)
+		return NULL;
+	while (n->rb_right)
+		n = n->rb_right;
+	return n;
+}
+
+struct rb_node *rb_next(const struct rb_node *node)
+{
+	struct rb_node *parent;
+
+	if (RB_EMPTY_NODE(node))
+		return NULL;
+
+	/*
+	 * If we have a right-hand child, go down and then left as far
+	 * as we can.
+	 */
+	if (node->rb_right) {
+		node = node->rb_right;
+		while (node->rb_left)
+			node = node->rb_left;
+		return (struct rb_node *)node;
+	}
+
+	/*
+	 * No right-hand children. Everything down and left is smaller than us,
+	 * so any 'next' node must be in the general direction of our parent.
+	 * Go up the tree; any time the ancestor is a right-hand child of its
+	 * parent, keep going up. First time it's a left-hand child of its
+	 * parent, said parent is our 'next' node.
+	 */
+	while ((parent = rb_parent(node)) && node == parent->rb_right)
+		node = parent;
+
+	return parent;
+}
+
+struct rb_node *rb_prev(const struct rb_node *node)
+{
+	struct rb_node *parent;
+
+	if (RB_EMPTY_NODE(node))
+		return NULL;
+
+	/*
+	 * If we have a left-hand child, go down and then right as far
+	 * as we can.
+	 */
+	if (node->rb_left) {
+		node = node->rb_left;
+		while (node->rb_right)
+			node = node->rb_right;
+		return (struct rb_node *)node;
+	}
+
+	/*
+	 * No left-hand children. Go up till we find an ancestor which
+	 * is a right-hand child of its parent.
+	 */
+	while ((parent = rb_parent(node)) && node == parent->rb_left)
+		node = parent;
+
+	return parent;
+}
+
+void rb_replace_node(struct rb_node *victim, struct rb_node *new,
+		     struct rb_root *root)
+{
+	struct rb_node *parent = rb_parent(victim);
+
+	/* Copy the pointers/colour from the victim to the replacement */
+	*new = *victim;
+
+	/* Set the surrounding nodes to point to the replacement */
+	if (victim->rb_left)
+		rb_set_parent(victim->rb_left, new);
+	if (victim->rb_right)
+		rb_set_parent(victim->rb_right, new);
+	__rb_change_child(victim, new, parent, root);
+}
+
+static struct rb_node *rb_left_deepest_node(const struct rb_node *node)
+{
+	for (;;) {
+		if (node->rb_left)
+			node = node->rb_left;
+		else if (node->rb_right)
+			node = node->rb_right;
+		else
+			return (struct rb_node *)node;
+	}
+}
+
+struct rb_node *rb_next_postorder(const struct rb_node *node)
+{
+	const struct rb_node *parent;
+	if (!node)
+		return NULL;
+	parent = rb_parent(node);
+
+	/* If we're sitting on node, we've already seen our children */
+	if (parent && node == parent->rb_left && parent->rb_right) {
+		/* If we are the parent's left node, go to the parent's right
+		 * node then all the way down to the left */
+		return rb_left_deepest_node(parent->rb_right);
+	} else
+		/* Otherwise we are the parent's right node, and the parent
+		 * should be next */
+		return (struct rb_node *)parent;
+}
+
+struct rb_node *rb_first_postorder(const struct rb_root *root)
+{
+	if (!root->rb_node)
+		return NULL;
+
+	return rb_left_deepest_node(root->rb_node);
+}
diff --git a/tools/lib/slab.c b/tools/lib/slab.c
new file mode 100644
index 000000000..981a21404
--- /dev/null
+++ b/tools/lib/slab.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <string.h>
+
+#include <urcu/uatomic.h>
+#include <linux/slab.h>
+#include <malloc.h>
+#include <linux/gfp.h>
+
+int kmalloc_nr_allocated;
+int kmalloc_verbose;
+
+void *kmalloc(size_t size, gfp_t gfp)
+{
+	void *ret;
+
+	if (!(gfp & __GFP_DIRECT_RECLAIM))
+		return NULL;
+
+	ret = malloc(size);
+	uatomic_inc(&kmalloc_nr_allocated);
+	if (kmalloc_verbose)
+		printf("Allocating %p from malloc\n", ret);
+	if (gfp & __GFP_ZERO)
+		memset(ret, 0, size);
+	return ret;
+}
+
+void kfree(void *p)
+{
+	if (!p)
+		return;
+	uatomic_dec(&kmalloc_nr_allocated);
+	if (kmalloc_verbose)
+		printf("Freeing %p to malloc\n", p);
+	free(p);
+}
+
+void *kmalloc_array(size_t n, size_t size, gfp_t gfp)
+{
+	void *ret;
+
+	if (!(gfp & __GFP_DIRECT_RECLAIM))
+		return NULL;
+
+	ret = calloc(n, size);
+	uatomic_inc(&kmalloc_nr_allocated);
+	if (kmalloc_verbose)
+		printf("Allocating %p from calloc\n", ret);
+	if (gfp & __GFP_ZERO)
+		memset(ret, 0, n * size);
+	return ret;
+}
diff --git a/tools/lib/str_error_r.c b/tools/lib/str_error_r.c
new file mode 100644
index 000000000..6aad8308a
--- /dev/null
+++ b/tools/lib/str_error_r.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef _GNU_SOURCE
+#include <string.h>
+#include <stdio.h>
+#include <linux/string.h>
+
+/*
+ * The tools so far have been using the strerror_r() GNU variant, that returns
+ * a string, be it the buffer passed or something else.
+ *
+ * But that, besides being tricky in cases where we expect that the function
+ * using strerror_r() returns the error formatted in a provided buffer (we have
+ * to check if it returned something else and copy that instead), breaks the
+ * build on systems not using glibc, like Alpine Linux, where musl libc is
+ * used.
+ *
+ * So, introduce yet another wrapper, str_error_r(), that has the GNU
+ * interface, but uses the portable XSI variant of strerror_r(), so that users
+ * rest asured that the provided buffer is used and it is what is returned.
+ */
+char *str_error_r(int errnum, char *buf, size_t buflen)
+{
+	int err = strerror_r(errnum, buf, buflen);
+	if (err)
+		snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, [buf], %zd)=%d", errnum, buflen, err);
+	return buf;
+}
diff --git a/tools/lib/string.c b/tools/lib/string.c
new file mode 100644
index 000000000..3126d2cff
--- /dev/null
+++ b/tools/lib/string.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/tools/lib/string.c
+ *
+ *  Copied from linux/lib/string.c, where it is:
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  More specifically, the first copied function was strtobool, which
+ *  was introduced by:
+ *
+ *  d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")
+ *  Author: Jonathan Cameron <jic23@cam.ac.uk>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/compiler.h>
+
+/**
+ * memdup - duplicate region of memory
+ *
+ * @src: memory region to duplicate
+ * @len: memory region length
+ */
+void *memdup(const void *src, size_t len)
+{
+	void *p = malloc(len);
+
+	if (p)
+		memcpy(p, src, len);
+
+	return p;
+}
+
+/**
+ * strtobool - convert common user inputs into boolean values
+ * @s: input string
+ * @res: result
+ *
+ * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
+ * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
+ * pointed to by res is updated upon finding a match.
+ */
+int strtobool(const char *s, bool *res)
+{
+	if (!s)
+		return -EINVAL;
+
+	switch (s[0]) {
+	case 'y':
+	case 'Y':
+	case '1':
+		*res = true;
+		return 0;
+	case 'n':
+	case 'N':
+	case '0':
+		*res = false;
+		return 0;
+	case 'o':
+	case 'O':
+		switch (s[1]) {
+		case 'n':
+		case 'N':
+			*res = true;
+			return 0;
+		case 'f':
+		case 'F':
+			*res = false;
+			return 0;
+		default:
+			break;
+		}
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * strlcpy - Copy a C-string into a sized buffer
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @size: size of destination buffer
+ *
+ * Compatible with *BSD: the result is always a valid
+ * NUL-terminated string that fits in the buffer (unless,
+ * of course, the buffer size is zero). It does not pad
+ * out the result like strncpy() does.
+ *
+ * If libc has strlcpy() then that version will override this
+ * implementation:
+ */
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wignored-attributes"
+#endif
+size_t __weak strlcpy(char *dest, const char *src, size_t size)
+{
+	size_t ret = strlen(src);
+
+	if (size) {
+		size_t len = (ret >= size) ? size - 1 : ret;
+		memcpy(dest, src, len);
+		dest[len] = '\0';
+	}
+	return ret;
+}
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
+/**
+ * skip_spaces - Removes leading whitespace from @str.
+ * @str: The string to be stripped.
+ *
+ * Returns a pointer to the first non-whitespace character in @str.
+ */
+char *skip_spaces(const char *str)
+{
+	while (isspace(*str))
+		++str;
+	return (char *)str;
+}
+
+/**
+ * strim - Removes leading and trailing whitespace from @s.
+ * @s: The string to be stripped.
+ *
+ * Note that the first trailing whitespace is replaced with a %NUL-terminator
+ * in the given string @s. Returns a pointer to the first non-whitespace
+ * character in @s.
+ */
+char *strim(char *s)
+{
+	size_t size;
+	char *end;
+
+	size = strlen(s);
+	if (!size)
+		return s;
+
+	end = s + size - 1;
+	while (end >= s && isspace(*end))
+		end--;
+	*(end + 1) = '\0';
+
+	return skip_spaces(s);
+}
+
+/*
+ * remove_spaces - Removes whitespaces from @s
+ */
+void remove_spaces(char *s)
+{
+	char *d = s;
+
+	do {
+		while (*d == ' ')
+			++d;
+	} while ((*s++ = *d++));
+}
+
+/**
+ * strreplace - Replace all occurrences of character in string.
+ * @s: The string to operate on.
+ * @old: The character being replaced.
+ * @new: The character @old is replaced with.
+ *
+ * Returns pointer to the nul byte at the end of @s.
+ */
+char *strreplace(char *s, char old, char new)
+{
+	for (; *s; ++s)
+		if (*s == old)
+			*s = new;
+	return s;
+}
+
+static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
+{
+	while (bytes) {
+		if (*start != value)
+			return (void *)start;
+		start++;
+		bytes--;
+	}
+	return NULL;
+}
+
+/**
+ * memchr_inv - Find an unmatching character in an area of memory.
+ * @start: The memory area
+ * @c: Find a character other than c
+ * @bytes: The size of the area.
+ *
+ * returns the address of the first character other than @c, or %NULL
+ * if the whole buffer contains just @c.
+ */
+void *memchr_inv(const void *start, int c, size_t bytes)
+{
+	u8 value = c;
+	u64 value64;
+	unsigned int words, prefix;
+
+	if (bytes <= 16)
+		return check_bytes8(start, value, bytes);
+
+	value64 = value;
+	value64 |= value64 << 8;
+	value64 |= value64 << 16;
+	value64 |= value64 << 32;
+
+	prefix = (unsigned long)start % 8;
+	if (prefix) {
+		u8 *r;
+
+		prefix = 8 - prefix;
+		r = check_bytes8(start, value, prefix);
+		if (r)
+			return r;
+		start += prefix;
+		bytes -= prefix;
+	}
+
+	words = bytes / 8;
+
+	while (words) {
+		if (*(u64 *)start != value64)
+			return check_bytes8(start, value, 8);
+		start += 8;
+		words--;
+	}
+
+	return check_bytes8(start, value, bytes % 8);
+}
diff --git a/tools/lib/subcmd/Build b/tools/lib/subcmd/Build
new file mode 100644
index 000000000..ee3128878
--- /dev/null
+++ b/tools/lib/subcmd/Build
@@ -0,0 +1,7 @@
+libsubcmd-y += exec-cmd.o
+libsubcmd-y += help.o
+libsubcmd-y += pager.o
+libsubcmd-y += parse-options.o
+libsubcmd-y += run-command.o
+libsubcmd-y += sigchain.o
+libsubcmd-y += subcmd-config.o
diff --git a/tools/lib/subcmd/Makefile b/tools/lib/subcmd/Makefile
new file mode 100644
index 000000000..9f1ddcf05
--- /dev/null
+++ b/tools/lib/subcmd/Makefile
@@ -0,0 +1,116 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../../scripts/Makefile.include
+include ../../scripts/utilities.mak		# QUIET_CLEAN
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+RM = rm -f
+
+MAKEFLAGS += --no-print-directory
+
+INSTALL = install
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+LIBFILE = $(OUTPUT)libsubcmd.a
+
+CFLAGS := -ggdb3 -Wall -Wextra -std=gnu99 -fPIC
+
+ifeq ($(DEBUG),0)
+  ifeq ($(feature-fortify-source), 1)
+    CFLAGS += -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2
+  endif
+endif
+
+ifeq ($(DEBUG),1)
+  CFLAGS += -O0
+else
+  CFLAGS += -O3
+endif
+
+# Treat warnings as errors unless directed not to
+ifneq ($(WERROR),0)
+  CFLAGS += -Werror
+endif
+
+CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
+
+CFLAGS += -I$(srctree)/tools/include/
+
+CFLAGS += $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
+
+SUBCMD_IN := $(OUTPUT)libsubcmd-in.o
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?=
+libdir = $(prefix)/$(libdir_relative)
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+include $(srctree)/tools/build/Makefile.include
+
+all: fixdep $(LIBFILE)
+
+$(SUBCMD_IN): fixdep FORCE
+	@$(MAKE) $(build)=libsubcmd
+
+$(LIBFILE): $(SUBCMD_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(SUBCMD_IN)
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
+	fi
+endef
+
+define do_install
+	if [ ! -d '$2' ]; then             \
+		$(INSTALL) -d -m 755 '$2'; \
+	fi;                                             \
+	$(INSTALL) $1 $(if $3,-m $3,) '$2'
+endef
+
+install_lib: $(LIBFILE)
+	$(call QUIET_INSTALL, $(LIBFILE)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fpR $(LIBFILE) $(DESTDIR)$(libdir_SQ)
+
+HDRS := exec-cmd.h help.h pager.h parse-options.h run-command.h
+INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/subcmd
+INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))
+
+$(INSTALL_HDRS): $(INSTALL_HDRS_PFX)/%.h: %.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/,644)
+
+install_headers: $(INSTALL_HDRS)
+	$(call QUIET_INSTALL, libsubcmd_headers)
+
+install: install_lib install_headers
+
+clean:
+	$(call QUIET_CLEAN, libsubcmd) $(RM) $(LIBFILE); \
+	find $(or $(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+
+FORCE:
+
+.PHONY: clean FORCE
diff --git a/tools/lib/subcmd/exec-cmd.c b/tools/lib/subcmd/exec-cmd.c
new file mode 100644
index 000000000..7739b5217
--- /dev/null
+++ b/tools/lib/subcmd/exec-cmd.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "subcmd-util.h"
+#include "exec-cmd.h"
+#include "subcmd-config.h"
+
+#define MAX_ARGS	32
+#define PATH_MAX	4096
+
+static const char *argv_exec_path;
+static const char *argv0_path;
+
+void exec_cmd_init(const char *exec_name, const char *prefix,
+		   const char *exec_path, const char *exec_path_env)
+{
+	subcmd_config.exec_name		= exec_name;
+	subcmd_config.prefix		= prefix;
+	subcmd_config.exec_path		= exec_path;
+	subcmd_config.exec_path_env	= exec_path_env;
+
+	/* Setup environment variable for invoked shell script. */
+	setenv("PREFIX", prefix, 1);
+}
+
+#define is_dir_sep(c) ((c) == '/')
+
+static int is_absolute_path(const char *path)
+{
+	return path[0] == '/';
+}
+
+static const char *get_pwd_cwd(char *buf, size_t sz)
+{
+	char *pwd;
+	struct stat cwd_stat, pwd_stat;
+	if (getcwd(buf, sz) == NULL)
+		return NULL;
+	pwd = getenv("PWD");
+	if (pwd && strcmp(pwd, buf)) {
+		stat(buf, &cwd_stat);
+		if (!stat(pwd, &pwd_stat) &&
+		    pwd_stat.st_dev == cwd_stat.st_dev &&
+		    pwd_stat.st_ino == cwd_stat.st_ino) {
+			strlcpy(buf, pwd, sz);
+		}
+	}
+	return buf;
+}
+
+static const char *make_nonrelative_path(char *buf, size_t sz, const char *path)
+{
+	if (is_absolute_path(path)) {
+		if (strlcpy(buf, path, sz) >= sz)
+			die("Too long path: %.*s", 60, path);
+	} else {
+		const char *cwd = get_pwd_cwd(buf, sz);
+
+		if (!cwd)
+			die("Cannot determine the current working directory");
+
+		if (strlen(cwd) + strlen(path) + 2 >= sz)
+			die("Too long path: %.*s", 60, path);
+
+		strcat(buf, "/");
+		strcat(buf, path);
+	}
+	return buf;
+}
+
+char *system_path(const char *path)
+{
+	char *buf = NULL;
+
+	if (is_absolute_path(path))
+		return strdup(path);
+
+	astrcatf(&buf, "%s/%s", subcmd_config.prefix, path);
+
+	return buf;
+}
+
+const char *extract_argv0_path(const char *argv0)
+{
+	const char *slash;
+
+	if (!argv0 || !*argv0)
+		return NULL;
+	slash = argv0 + strlen(argv0);
+
+	while (argv0 <= slash && !is_dir_sep(*slash))
+		slash--;
+
+	if (slash >= argv0) {
+		argv0_path = strndup(argv0, slash - argv0);
+		return argv0_path ? slash + 1 : NULL;
+	}
+
+	return argv0;
+}
+
+void set_argv_exec_path(const char *exec_path)
+{
+	argv_exec_path = exec_path;
+	/*
+	 * Propagate this setting to external programs.
+	 */
+	setenv(subcmd_config.exec_path_env, exec_path, 1);
+}
+
+
+/* Returns the highest-priority location to look for subprograms. */
+char *get_argv_exec_path(void)
+{
+	char *env;
+
+	if (argv_exec_path)
+		return strdup(argv_exec_path);
+
+	env = getenv(subcmd_config.exec_path_env);
+	if (env && *env)
+		return strdup(env);
+
+	return system_path(subcmd_config.exec_path);
+}
+
+static void add_path(char **out, const char *path)
+{
+	if (path && *path) {
+		if (is_absolute_path(path))
+			astrcat(out, path);
+		else {
+			char buf[PATH_MAX];
+
+			astrcat(out, make_nonrelative_path(buf, sizeof(buf), path));
+		}
+
+		astrcat(out, ":");
+	}
+}
+
+void setup_path(void)
+{
+	const char *old_path = getenv("PATH");
+	char *new_path = NULL;
+	char *tmp = get_argv_exec_path();
+
+	add_path(&new_path, tmp);
+	add_path(&new_path, argv0_path);
+	free(tmp);
+
+	if (old_path)
+		astrcat(&new_path, old_path);
+	else
+		astrcat(&new_path, "/usr/local/bin:/usr/bin:/bin");
+
+	setenv("PATH", new_path, 1);
+
+	free(new_path);
+}
+
+static const char **prepare_exec_cmd(const char **argv)
+{
+	int argc;
+	const char **nargv;
+
+	for (argc = 0; argv[argc]; argc++)
+		; /* just counting */
+	nargv = malloc(sizeof(*nargv) * (argc + 2));
+
+	nargv[0] = subcmd_config.exec_name;
+	for (argc = 0; argv[argc]; argc++)
+		nargv[argc + 1] = argv[argc];
+	nargv[argc + 1] = NULL;
+	return nargv;
+}
+
+int execv_cmd(const char **argv) {
+	const char **nargv = prepare_exec_cmd(argv);
+
+	/* execvp() can only ever return if it fails */
+	execvp(subcmd_config.exec_name, (char **)nargv);
+
+	free(nargv);
+	return -1;
+}
+
+
+int execl_cmd(const char *cmd,...)
+{
+	int argc;
+	const char *argv[MAX_ARGS + 1];
+	const char *arg;
+	va_list param;
+
+	va_start(param, cmd);
+	argv[0] = cmd;
+	argc = 1;
+	while (argc < MAX_ARGS) {
+		arg = argv[argc++] = va_arg(param, char *);
+		if (!arg)
+			break;
+	}
+	va_end(param);
+	if (MAX_ARGS <= argc) {
+		fprintf(stderr, " Error: too many args to run %s\n", cmd);
+		return -1;
+	}
+
+	argv[argc] = NULL;
+	return execv_cmd(argv);
+}
diff --git a/tools/lib/subcmd/exec-cmd.h b/tools/lib/subcmd/exec-cmd.h
new file mode 100644
index 000000000..aba591b8d
--- /dev/null
+++ b/tools/lib/subcmd/exec-cmd.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_EXEC_CMD_H
+#define __SUBCMD_EXEC_CMD_H
+
+extern void exec_cmd_init(const char *exec_name, const char *prefix,
+			  const char *exec_path, const char *exec_path_env);
+
+extern void set_argv_exec_path(const char *exec_path);
+extern const char *extract_argv0_path(const char *path);
+extern void setup_path(void);
+extern int execv_cmd(const char **argv); /* NULL terminated */
+extern int execl_cmd(const char *cmd, ...);
+/* get_argv_exec_path and system_path return malloc'd string, caller must free it */
+extern char *get_argv_exec_path(void);
+extern char *system_path(const char *path);
+
+#endif /* __SUBCMD_EXEC_CMD_H */
diff --git a/tools/lib/subcmd/help.c b/tools/lib/subcmd/help.c
new file mode 100644
index 000000000..db94aa685
--- /dev/null
+++ b/tools/lib/subcmd/help.c
@@ -0,0 +1,301 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <linux/string.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <assert.h>
+#include "subcmd-util.h"
+#include "help.h"
+#include "exec-cmd.h"
+
+void add_cmdname(struct cmdnames *cmds, const char *name, size_t len)
+{
+	struct cmdname *ent = malloc(sizeof(*ent) + len + 1);
+	if (!ent)
+		return;
+
+	ent->len = len;
+	memcpy(ent->name, name, len);
+	ent->name[len] = 0;
+
+	ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
+	cmds->names[cmds->cnt++] = ent;
+}
+
+void clean_cmdnames(struct cmdnames *cmds)
+{
+	unsigned int i;
+
+	for (i = 0; i < cmds->cnt; ++i)
+		zfree(&cmds->names[i]);
+	zfree(&cmds->names);
+	cmds->cnt = 0;
+	cmds->alloc = 0;
+}
+
+int cmdname_compare(const void *a_, const void *b_)
+{
+	struct cmdname *a = *(struct cmdname **)a_;
+	struct cmdname *b = *(struct cmdname **)b_;
+	return strcmp(a->name, b->name);
+}
+
+void uniq(struct cmdnames *cmds)
+{
+	unsigned int i, j;
+
+	if (!cmds->cnt)
+		return;
+
+	for (i = 1; i < cmds->cnt; i++) {
+		if (!strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
+			zfree(&cmds->names[i - 1]);
+	}
+	for (i = 0, j = 0; i < cmds->cnt; i++) {
+		if (cmds->names[i]) {
+			if (i == j)
+				j++;
+			else
+				cmds->names[j++] = cmds->names[i];
+		}
+	}
+	cmds->cnt = j;
+	while (j < i)
+		cmds->names[j++] = NULL;
+}
+
+void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
+{
+	size_t ci, cj, ei;
+	int cmp;
+
+	if (!excludes->cnt)
+		return;
+
+	ci = cj = ei = 0;
+	while (ci < cmds->cnt && ei < excludes->cnt) {
+		cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
+		if (cmp < 0) {
+			if (ci == cj) {
+				ci++;
+				cj++;
+			} else {
+				cmds->names[cj++] = cmds->names[ci];
+				cmds->names[ci++] = NULL;
+			}
+		} else if (cmp == 0) {
+			zfree(&cmds->names[ci]);
+			ci++;
+			ei++;
+		} else if (cmp > 0) {
+			ei++;
+		}
+	}
+	while (ci < cmds->cnt) {
+		if (ci != cj) {
+			cmds->names[cj] = cmds->names[ci];
+			cmds->names[ci] = NULL;
+		}
+		ci++;
+		cj++;
+	}
+	for (ci = cj; ci < cmds->cnt; ci++)
+		assert(cmds->names[ci] == NULL);
+	cmds->cnt = cj;
+}
+
+static void get_term_dimensions(struct winsize *ws)
+{
+	char *s = getenv("LINES");
+
+	if (s != NULL) {
+		ws->ws_row = atoi(s);
+		s = getenv("COLUMNS");
+		if (s != NULL) {
+			ws->ws_col = atoi(s);
+			if (ws->ws_row && ws->ws_col)
+				return;
+		}
+	}
+#ifdef TIOCGWINSZ
+	if (ioctl(1, TIOCGWINSZ, ws) == 0 &&
+	    ws->ws_row && ws->ws_col)
+		return;
+#endif
+	ws->ws_row = 25;
+	ws->ws_col = 80;
+}
+
+static void pretty_print_string_list(struct cmdnames *cmds, int longest)
+{
+	int cols = 1, rows;
+	int space = longest + 1; /* min 1 SP between words */
+	struct winsize win;
+	int max_cols;
+	int i, j;
+
+	get_term_dimensions(&win);
+	max_cols = win.ws_col - 1; /* don't print *on* the edge */
+
+	if (space < max_cols)
+		cols = max_cols / space;
+	rows = (cmds->cnt + cols - 1) / cols;
+
+	for (i = 0; i < rows; i++) {
+		printf("  ");
+
+		for (j = 0; j < cols; j++) {
+			unsigned int n = j * rows + i;
+			unsigned int size = space;
+
+			if (n >= cmds->cnt)
+				break;
+			if (j == cols-1 || n + rows >= cmds->cnt)
+				size = 1;
+			printf("%-*s", size, cmds->names[n]->name);
+		}
+		putchar('\n');
+	}
+}
+
+static int is_executable(const char *name)
+{
+	struct stat st;
+
+	if (stat(name, &st) || /* stat, not lstat */
+	    !S_ISREG(st.st_mode))
+		return 0;
+
+	return st.st_mode & S_IXUSR;
+}
+
+static int has_extension(const char *filename, const char *ext)
+{
+	size_t len = strlen(filename);
+	size_t extlen = strlen(ext);
+
+	return len > extlen && !memcmp(filename + len - extlen, ext, extlen);
+}
+
+static void list_commands_in_dir(struct cmdnames *cmds,
+					 const char *path,
+					 const char *prefix)
+{
+	int prefix_len;
+	DIR *dir = opendir(path);
+	struct dirent *de;
+	char *buf = NULL;
+
+	if (!dir)
+		return;
+	if (!prefix)
+		prefix = "perf-";
+	prefix_len = strlen(prefix);
+
+	astrcatf(&buf, "%s/", path);
+
+	while ((de = readdir(dir)) != NULL) {
+		int entlen;
+
+		if (!strstarts(de->d_name, prefix))
+			continue;
+
+		astrcat(&buf, de->d_name);
+		if (!is_executable(buf))
+			continue;
+
+		entlen = strlen(de->d_name) - prefix_len;
+		if (has_extension(de->d_name, ".exe"))
+			entlen -= 4;
+
+		add_cmdname(cmds, de->d_name + prefix_len, entlen);
+	}
+	closedir(dir);
+	free(buf);
+}
+
+void load_command_list(const char *prefix,
+		struct cmdnames *main_cmds,
+		struct cmdnames *other_cmds)
+{
+	const char *env_path = getenv("PATH");
+	char *exec_path = get_argv_exec_path();
+
+	if (exec_path) {
+		list_commands_in_dir(main_cmds, exec_path, prefix);
+		qsort(main_cmds->names, main_cmds->cnt,
+		      sizeof(*main_cmds->names), cmdname_compare);
+		uniq(main_cmds);
+	}
+
+	if (env_path) {
+		char *paths, *path, *colon;
+		path = paths = strdup(env_path);
+		while (1) {
+			if ((colon = strchr(path, ':')))
+				*colon = 0;
+			if (!exec_path || strcmp(path, exec_path))
+				list_commands_in_dir(other_cmds, path, prefix);
+
+			if (!colon)
+				break;
+			path = colon + 1;
+		}
+		free(paths);
+
+		qsort(other_cmds->names, other_cmds->cnt,
+		      sizeof(*other_cmds->names), cmdname_compare);
+		uniq(other_cmds);
+	}
+	free(exec_path);
+	exclude_cmds(other_cmds, main_cmds);
+}
+
+void list_commands(const char *title, struct cmdnames *main_cmds,
+		   struct cmdnames *other_cmds)
+{
+	unsigned int i, longest = 0;
+
+	for (i = 0; i < main_cmds->cnt; i++)
+		if (longest < main_cmds->names[i]->len)
+			longest = main_cmds->names[i]->len;
+	for (i = 0; i < other_cmds->cnt; i++)
+		if (longest < other_cmds->names[i]->len)
+			longest = other_cmds->names[i]->len;
+
+	if (main_cmds->cnt) {
+		char *exec_path = get_argv_exec_path();
+		printf("available %s in '%s'\n", title, exec_path);
+		printf("----------------");
+		mput_char('-', strlen(title) + strlen(exec_path));
+		putchar('\n');
+		pretty_print_string_list(main_cmds, longest);
+		putchar('\n');
+		free(exec_path);
+	}
+
+	if (other_cmds->cnt) {
+		printf("%s available from elsewhere on your $PATH\n", title);
+		printf("---------------------------------------");
+		mput_char('-', strlen(title));
+		putchar('\n');
+		pretty_print_string_list(other_cmds, longest);
+		putchar('\n');
+	}
+}
+
+int is_in_cmdlist(struct cmdnames *c, const char *s)
+{
+	unsigned int i;
+
+	for (i = 0; i < c->cnt; i++)
+		if (!strcmp(s, c->names[i]->name))
+			return 1;
+	return 0;
+}
diff --git a/tools/lib/subcmd/help.h b/tools/lib/subcmd/help.h
new file mode 100644
index 000000000..355c066c8
--- /dev/null
+++ b/tools/lib/subcmd/help.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_HELP_H
+#define __SUBCMD_HELP_H
+
+#include <sys/types.h>
+#include <stdio.h>
+
+struct cmdnames {
+	size_t alloc;
+	size_t cnt;
+	struct cmdname {
+		size_t len; /* also used for similarity index in help.c */
+		char name[];
+	} **names;
+};
+
+static inline void mput_char(char c, unsigned int num)
+{
+	while(num--)
+		putchar(c);
+}
+
+void load_command_list(const char *prefix,
+		struct cmdnames *main_cmds,
+		struct cmdnames *other_cmds);
+void add_cmdname(struct cmdnames *cmds, const char *name, size_t len);
+void clean_cmdnames(struct cmdnames *cmds);
+int cmdname_compare(const void *a, const void *b);
+void uniq(struct cmdnames *cmds);
+/* Here we require that excludes is a sorted list. */
+void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes);
+int is_in_cmdlist(struct cmdnames *c, const char *s);
+void list_commands(const char *title, struct cmdnames *main_cmds,
+		   struct cmdnames *other_cmds);
+
+#endif /* __SUBCMD_HELP_H */
diff --git a/tools/lib/subcmd/pager.c b/tools/lib/subcmd/pager.c
new file mode 100644
index 000000000..e3d47b59b
--- /dev/null
+++ b/tools/lib/subcmd/pager.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <sys/select.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+#include "pager.h"
+#include "run-command.h"
+#include "sigchain.h"
+#include "subcmd-config.h"
+
+/*
+ * This is split up from the rest of git so that we can do
+ * something different on Windows.
+ */
+
+static int spawned_pager;
+static int pager_columns;
+
+void pager_init(const char *pager_env)
+{
+	subcmd_config.pager_env = pager_env;
+}
+
+static const char *forced_pager;
+
+void force_pager(const char *pager)
+{
+	forced_pager = pager;
+}
+
+static void pager_preexec(void)
+{
+	/*
+	 * Work around bug in "less" by not starting it until we
+	 * have real input
+	 */
+	fd_set in;
+	fd_set exception;
+
+	FD_ZERO(&in);
+	FD_ZERO(&exception);
+	FD_SET(0, &in);
+	FD_SET(0, &exception);
+	select(1, &in, NULL, &exception, NULL);
+
+	setenv("LESS", "FRSX", 0);
+}
+
+static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
+static struct child_process pager_process;
+
+static void wait_for_pager(void)
+{
+	fflush(stdout);
+	fflush(stderr);
+	/* signal EOF to pager */
+	close(1);
+	close(2);
+	finish_command(&pager_process);
+}
+
+static void wait_for_pager_signal(int signo)
+{
+	wait_for_pager();
+	sigchain_pop(signo);
+	raise(signo);
+}
+
+void setup_pager(void)
+{
+	const char *pager = getenv(subcmd_config.pager_env);
+	struct winsize sz;
+
+	if (forced_pager)
+		pager = forced_pager;
+	if (!isatty(1) && !forced_pager)
+		return;
+	if (ioctl(1, TIOCGWINSZ, &sz) == 0)
+		pager_columns = sz.ws_col;
+	if (!pager)
+		pager = getenv("PAGER");
+	if (!(pager || access("/usr/bin/pager", X_OK)))
+		pager = "/usr/bin/pager";
+	if (!(pager || access("/usr/bin/less", X_OK)))
+		pager = "/usr/bin/less";
+	if (!pager)
+		pager = "cat";
+	if (!*pager || !strcmp(pager, "cat"))
+		return;
+
+	spawned_pager = 1; /* means we are emitting to terminal */
+
+	/* spawn the pager */
+	pager_argv[2] = pager;
+	pager_process.argv = pager_argv;
+	pager_process.in = -1;
+	pager_process.preexec_cb = pager_preexec;
+
+	if (start_command(&pager_process))
+		return;
+
+	/* original process continues, but writes to the pipe */
+	dup2(pager_process.in, 1);
+	if (isatty(2))
+		dup2(pager_process.in, 2);
+	close(pager_process.in);
+
+	/* this makes sure that the parent terminates after the pager */
+	sigchain_push_common(wait_for_pager_signal);
+	atexit(wait_for_pager);
+}
+
+int pager_in_use(void)
+{
+	return spawned_pager;
+}
+
+int pager_get_columns(void)
+{
+	char *s;
+
+	s = getenv("COLUMNS");
+	if (s)
+		return atoi(s);
+
+	return (pager_columns ? pager_columns : 80) - 2;
+}
diff --git a/tools/lib/subcmd/pager.h b/tools/lib/subcmd/pager.h
new file mode 100644
index 000000000..a81896469
--- /dev/null
+++ b/tools/lib/subcmd/pager.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_PAGER_H
+#define __SUBCMD_PAGER_H
+
+extern void pager_init(const char *pager_env);
+
+extern void setup_pager(void);
+extern int pager_in_use(void);
+extern int pager_get_columns(void);
+extern void force_pager(const char *);
+
+#endif /* __SUBCMD_PAGER_H */
diff --git a/tools/lib/subcmd/parse-options.c b/tools/lib/subcmd/parse-options.c
new file mode 100644
index 000000000..e83200e9f
--- /dev/null
+++ b/tools/lib/subcmd/parse-options.c
@@ -0,0 +1,1090 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <ctype.h>
+#include "subcmd-util.h"
+#include "parse-options.h"
+#include "subcmd-config.h"
+#include "pager.h"
+
+#define OPT_SHORT 1
+#define OPT_UNSET 2
+
+char *error_buf;
+
+static int opterror(const struct option *opt, const char *reason, int flags)
+{
+	if (flags & OPT_SHORT)
+		fprintf(stderr, " Error: switch `%c' %s", opt->short_name, reason);
+	else if (flags & OPT_UNSET)
+		fprintf(stderr, " Error: option `no-%s' %s", opt->long_name, reason);
+	else
+		fprintf(stderr, " Error: option `%s' %s", opt->long_name, reason);
+
+	return -1;
+}
+
+static const char *skip_prefix(const char *str, const char *prefix)
+{
+	size_t len = strlen(prefix);
+	return strncmp(str, prefix, len) ? NULL : str + len;
+}
+
+static void optwarning(const struct option *opt, const char *reason, int flags)
+{
+	if (flags & OPT_SHORT)
+		fprintf(stderr, " Warning: switch `%c' %s", opt->short_name, reason);
+	else if (flags & OPT_UNSET)
+		fprintf(stderr, " Warning: option `no-%s' %s", opt->long_name, reason);
+	else
+		fprintf(stderr, " Warning: option `%s' %s", opt->long_name, reason);
+}
+
+static int get_arg(struct parse_opt_ctx_t *p, const struct option *opt,
+		   int flags, const char **arg)
+{
+	const char *res;
+
+	if (p->opt) {
+		res = p->opt;
+		p->opt = NULL;
+	} else if ((opt->flags & PARSE_OPT_LASTARG_DEFAULT) && (p->argc == 1 ||
+		    **(p->argv + 1) == '-')) {
+		res = (const char *)opt->defval;
+	} else if (p->argc > 1) {
+		p->argc--;
+		res = *++p->argv;
+	} else
+		return opterror(opt, "requires a value", flags);
+	if (arg)
+		*arg = res;
+	return 0;
+}
+
+static int get_value(struct parse_opt_ctx_t *p,
+		     const struct option *opt, int flags)
+{
+	const char *s, *arg = NULL;
+	const int unset = flags & OPT_UNSET;
+	int err;
+	bool force_defval = false;
+
+	if (unset && p->opt)
+		return opterror(opt, "takes no value", flags);
+	if (unset && (opt->flags & PARSE_OPT_NONEG))
+		return opterror(opt, "isn't available", flags);
+	if (opt->flags & PARSE_OPT_DISABLED)
+		return opterror(opt, "is not usable", flags);
+
+	if (opt->flags & PARSE_OPT_EXCLUSIVE) {
+		if (p->excl_opt && p->excl_opt != opt) {
+			char msg[128];
+
+			if (((flags & OPT_SHORT) && p->excl_opt->short_name) ||
+			    p->excl_opt->long_name == NULL) {
+				snprintf(msg, sizeof(msg), "cannot be used with switch `%c'",
+					 p->excl_opt->short_name);
+			} else {
+				snprintf(msg, sizeof(msg), "cannot be used with %s",
+					 p->excl_opt->long_name);
+			}
+			opterror(opt, msg, flags);
+			return -3;
+		}
+		p->excl_opt = opt;
+	}
+	if (!(flags & OPT_SHORT) && p->opt) {
+		switch (opt->type) {
+		case OPTION_CALLBACK:
+			if (!(opt->flags & PARSE_OPT_NOARG))
+				break;
+			/* FALLTHROUGH */
+		case OPTION_BOOLEAN:
+		case OPTION_INCR:
+		case OPTION_BIT:
+		case OPTION_SET_UINT:
+		case OPTION_SET_PTR:
+			return opterror(opt, "takes no value", flags);
+		case OPTION_END:
+		case OPTION_ARGUMENT:
+		case OPTION_GROUP:
+		case OPTION_STRING:
+		case OPTION_INTEGER:
+		case OPTION_UINTEGER:
+		case OPTION_LONG:
+		case OPTION_ULONG:
+		case OPTION_U64:
+		default:
+			break;
+		}
+	}
+
+	if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
+		if (!(p->flags & PARSE_OPT_OPTARG_ALLOW_NEXT)) {
+			/*
+			 * If the option has an optional argument, and the argument is not
+			 * provided in the option itself, do not attempt to get it from
+			 * the next argument, unless PARSE_OPT_OPTARG_ALLOW_NEXT is set.
+			 *
+			 * This prevents a non-option argument from being interpreted as an
+			 * optional argument of a preceding option, for example:
+			 *
+			 * $ cmd --opt val
+			 * -> is "val" argument of "--opt" or a separate non-option
+			 * argument?
+			 *
+			 * With PARSE_OPT_OPTARG_ALLOW_NEXT, "val" is interpreted as
+			 * the argument of "--opt", i.e. the same as "--opt=val".
+			 * Without PARSE_OPT_OPTARG_ALLOW_NEXT, --opt is interpreted
+			 * as having the default value, and "val" as a separate non-option
+			 * argument.
+			 *
+			 * PARSE_OPT_OPTARG_ALLOW_NEXT is useful for commands that take no
+			 * non-option arguments and want to allow more flexibility in
+			 * optional argument passing.
+			 */
+			force_defval = true;
+		}
+
+		if (p->argc <= 1 || p->argv[1][0] == '-') {
+			/*
+			 * If next argument is an option or does not exist,
+			 * use the default value.
+			 */
+			force_defval = true;
+		}
+	}
+
+	if (opt->flags & PARSE_OPT_NOBUILD) {
+		char reason[128];
+		bool noarg = false;
+
+		err = snprintf(reason, sizeof(reason),
+				opt->flags & PARSE_OPT_CANSKIP ?
+					"is being ignored because %s " :
+					"is not available because %s",
+				opt->build_opt);
+		reason[sizeof(reason) - 1] = '\0';
+
+		if (err < 0)
+			strncpy(reason, opt->flags & PARSE_OPT_CANSKIP ?
+					"is being ignored" :
+					"is not available",
+					sizeof(reason));
+
+		if (!(opt->flags & PARSE_OPT_CANSKIP))
+			return opterror(opt, reason, flags);
+
+		err = 0;
+		if (unset)
+			noarg = true;
+		if (opt->flags & PARSE_OPT_NOARG)
+			noarg = true;
+		if (force_defval)
+			noarg = true;
+
+		switch (opt->type) {
+		case OPTION_BOOLEAN:
+		case OPTION_INCR:
+		case OPTION_BIT:
+		case OPTION_SET_UINT:
+		case OPTION_SET_PTR:
+		case OPTION_END:
+		case OPTION_ARGUMENT:
+		case OPTION_GROUP:
+			noarg = true;
+			break;
+		case OPTION_CALLBACK:
+		case OPTION_STRING:
+		case OPTION_INTEGER:
+		case OPTION_UINTEGER:
+		case OPTION_LONG:
+		case OPTION_ULONG:
+		case OPTION_U64:
+		default:
+			break;
+		}
+
+		if (!noarg)
+			err = get_arg(p, opt, flags, NULL);
+		if (err)
+			return err;
+
+		optwarning(opt, reason, flags);
+		return 0;
+	}
+
+	switch (opt->type) {
+	case OPTION_BIT:
+		if (unset)
+			*(int *)opt->value &= ~opt->defval;
+		else
+			*(int *)opt->value |= opt->defval;
+		return 0;
+
+	case OPTION_BOOLEAN:
+		*(bool *)opt->value = unset ? false : true;
+		if (opt->set)
+			*(bool *)opt->set = true;
+		return 0;
+
+	case OPTION_INCR:
+		*(int *)opt->value = unset ? 0 : *(int *)opt->value + 1;
+		return 0;
+
+	case OPTION_SET_UINT:
+		*(unsigned int *)opt->value = unset ? 0 : opt->defval;
+		return 0;
+
+	case OPTION_SET_PTR:
+		*(void **)opt->value = unset ? NULL : (void *)opt->defval;
+		return 0;
+
+	case OPTION_STRING:
+		err = 0;
+		if (unset)
+			*(const char **)opt->value = NULL;
+		else if (force_defval)
+			*(const char **)opt->value = (const char *)opt->defval;
+		else
+			err = get_arg(p, opt, flags, (const char **)opt->value);
+
+		if (opt->set)
+			*(bool *)opt->set = true;
+
+		/* PARSE_OPT_NOEMPTY: Allow NULL but disallow empty string. */
+		if (opt->flags & PARSE_OPT_NOEMPTY) {
+			const char *val = *(const char **)opt->value;
+
+			if (!val)
+				return err;
+
+			/* Similar to unset if we are given an empty string. */
+			if (val[0] == '\0') {
+				*(const char **)opt->value = NULL;
+				return 0;
+			}
+		}
+
+		return err;
+
+	case OPTION_CALLBACK:
+		if (opt->set)
+			*(bool *)opt->set = true;
+
+		if (unset)
+			return (*opt->callback)(opt, NULL, 1) ? (-1) : 0;
+		if (opt->flags & PARSE_OPT_NOARG)
+			return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
+		if (force_defval)
+			return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
+		if (get_arg(p, opt, flags, &arg))
+			return -1;
+		return (*opt->callback)(opt, arg, 0) ? (-1) : 0;
+
+	case OPTION_INTEGER:
+		if (unset) {
+			*(int *)opt->value = 0;
+			return 0;
+		}
+		if (force_defval) {
+			*(int *)opt->value = opt->defval;
+			return 0;
+		}
+		if (get_arg(p, opt, flags, &arg))
+			return -1;
+		*(int *)opt->value = strtol(arg, (char **)&s, 10);
+		if (*s)
+			return opterror(opt, "expects a numerical value", flags);
+		return 0;
+
+	case OPTION_UINTEGER:
+		if (unset) {
+			*(unsigned int *)opt->value = 0;
+			return 0;
+		}
+		if (force_defval) {
+			*(unsigned int *)opt->value = opt->defval;
+			return 0;
+		}
+		if (get_arg(p, opt, flags, &arg))
+			return -1;
+		if (arg[0] == '-')
+			return opterror(opt, "expects an unsigned numerical value", flags);
+		*(unsigned int *)opt->value = strtol(arg, (char **)&s, 10);
+		if (*s)
+			return opterror(opt, "expects a numerical value", flags);
+		return 0;
+
+	case OPTION_LONG:
+		if (unset) {
+			*(long *)opt->value = 0;
+			return 0;
+		}
+		if (force_defval) {
+			*(long *)opt->value = opt->defval;
+			return 0;
+		}
+		if (get_arg(p, opt, flags, &arg))
+			return -1;
+		*(long *)opt->value = strtol(arg, (char **)&s, 10);
+		if (*s)
+			return opterror(opt, "expects a numerical value", flags);
+		return 0;
+
+	case OPTION_ULONG:
+		if (unset) {
+			*(unsigned long *)opt->value = 0;
+			return 0;
+		}
+		if (force_defval) {
+			*(unsigned long *)opt->value = opt->defval;
+			return 0;
+		}
+		if (get_arg(p, opt, flags, &arg))
+			return -1;
+		*(unsigned long *)opt->value = strtoul(arg, (char **)&s, 10);
+		if (*s)
+			return opterror(opt, "expects a numerical value", flags);
+		return 0;
+
+	case OPTION_U64:
+		if (unset) {
+			*(u64 *)opt->value = 0;
+			return 0;
+		}
+		if (force_defval) {
+			*(u64 *)opt->value = opt->defval;
+			return 0;
+		}
+		if (get_arg(p, opt, flags, &arg))
+			return -1;
+		if (arg[0] == '-')
+			return opterror(opt, "expects an unsigned numerical value", flags);
+		*(u64 *)opt->value = strtoull(arg, (char **)&s, 10);
+		if (*s)
+			return opterror(opt, "expects a numerical value", flags);
+		return 0;
+
+	case OPTION_END:
+	case OPTION_ARGUMENT:
+	case OPTION_GROUP:
+	default:
+		die("should not happen, someone must be hit on the forehead");
+	}
+}
+
+static int parse_short_opt(struct parse_opt_ctx_t *p, const struct option *options)
+{
+retry:
+	for (; options->type != OPTION_END; options++) {
+		if (options->short_name == *p->opt) {
+			p->opt = p->opt[1] ? p->opt + 1 : NULL;
+			return get_value(p, options, OPT_SHORT);
+		}
+	}
+
+	if (options->parent) {
+		options = options->parent;
+		goto retry;
+	}
+
+	return -2;
+}
+
+static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
+                          const struct option *options)
+{
+	const char *arg_end = strchr(arg, '=');
+	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
+	int abbrev_flags = 0, ambiguous_flags = 0;
+
+	if (!arg_end)
+		arg_end = arg + strlen(arg);
+
+retry:
+	for (; options->type != OPTION_END; options++) {
+		const char *rest;
+		int flags = 0;
+
+		if (!options->long_name)
+			continue;
+
+		rest = skip_prefix(arg, options->long_name);
+		if (options->type == OPTION_ARGUMENT) {
+			if (!rest)
+				continue;
+			if (*rest == '=')
+				return opterror(options, "takes no value", flags);
+			if (*rest)
+				continue;
+			p->out[p->cpidx++] = arg - 2;
+			return 0;
+		}
+		if (!rest) {
+			if (strstarts(options->long_name, "no-") &&
+			    !(options->flags & PARSE_OPT_NOAUTONEG)) {
+				/*
+				 * The long name itself starts with "no-", so
+				 * accept the option without "no-" so that users
+				 * do not have to enter "no-no-" to get the
+				 * negation.
+				 */
+				rest = skip_prefix(arg, options->long_name + 3);
+				if (rest) {
+					flags |= OPT_UNSET;
+					goto match;
+				}
+				/* Abbreviated case */
+				if (strstarts(options->long_name + 3, arg)) {
+					flags |= OPT_UNSET;
+					goto is_abbreviated;
+				}
+			}
+			/* abbreviated? */
+			if (!strncmp(options->long_name, arg, arg_end - arg)) {
+is_abbreviated:
+				if (abbrev_option) {
+					/*
+					 * If this is abbreviated, it is
+					 * ambiguous. So when there is no
+					 * exact match later, we need to
+					 * error out.
+					 */
+					ambiguous_option = abbrev_option;
+					ambiguous_flags = abbrev_flags;
+				}
+				if (!(flags & OPT_UNSET) && *arg_end)
+					p->opt = arg_end + 1;
+				abbrev_option = options;
+				abbrev_flags = flags;
+				continue;
+			}
+			/* negated and abbreviated very much? */
+			if (strstarts("no-", arg) && !(options->flags & PARSE_OPT_NOAUTONEG)) {
+				flags |= OPT_UNSET;
+				goto is_abbreviated;
+			}
+			/* negated? */
+			if (strncmp(arg, "no-", 3) || (options->flags & PARSE_OPT_NOAUTONEG))
+				continue;
+			flags |= OPT_UNSET;
+			rest = skip_prefix(arg + 3, options->long_name);
+			/* abbreviated and negated? */
+			if (!rest && strstarts(options->long_name, arg + 3))
+				goto is_abbreviated;
+			if (!rest)
+				continue;
+		}
+match:
+		if (*rest) {
+			if (*rest != '=')
+				continue;
+			p->opt = rest + 1;
+		}
+		return get_value(p, options, flags);
+	}
+
+	if (ambiguous_option) {
+		 fprintf(stderr,
+			 " Error: Ambiguous option: %s (could be --%s%s or --%s%s)\n",
+			 arg,
+			 (ambiguous_flags & OPT_UNSET) ?  "no-" : "",
+			 ambiguous_option->long_name,
+			 (abbrev_flags & OPT_UNSET) ?  "no-" : "",
+			 abbrev_option->long_name);
+		 return -1;
+	}
+	if (abbrev_option)
+		return get_value(p, abbrev_option, abbrev_flags);
+
+	if (options->parent) {
+		options = options->parent;
+		goto retry;
+	}
+
+	return -2;
+}
+
+static void check_typos(const char *arg, const struct option *options)
+{
+	if (strlen(arg) < 3)
+		return;
+
+	if (strstarts(arg, "no-")) {
+		fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)\n", arg);
+		exit(129);
+	}
+
+	for (; options->type != OPTION_END; options++) {
+		if (!options->long_name)
+			continue;
+		if (strstarts(options->long_name, arg)) {
+			fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)\n", arg);
+			exit(129);
+		}
+	}
+}
+
+static void parse_options_start(struct parse_opt_ctx_t *ctx,
+				int argc, const char **argv, int flags)
+{
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->argc = argc - 1;
+	ctx->argv = argv + 1;
+	ctx->out  = argv;
+	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
+	ctx->flags = flags;
+	if ((flags & PARSE_OPT_KEEP_UNKNOWN) &&
+	    (flags & PARSE_OPT_STOP_AT_NON_OPTION))
+		die("STOP_AT_NON_OPTION and KEEP_UNKNOWN don't go together");
+}
+
+static int usage_with_options_internal(const char * const *,
+				       const struct option *, int,
+				       struct parse_opt_ctx_t *);
+
+static int parse_options_step(struct parse_opt_ctx_t *ctx,
+			      const struct option *options,
+			      const char * const usagestr[])
+{
+	int internal_help = !(ctx->flags & PARSE_OPT_NO_INTERNAL_HELP);
+	int excl_short_opt = 1;
+	const char *arg;
+
+	/* we must reset ->opt, unknown short option leave it dangling */
+	ctx->opt = NULL;
+
+	for (; ctx->argc; ctx->argc--, ctx->argv++) {
+		arg = ctx->argv[0];
+		if (*arg != '-' || !arg[1]) {
+			if (ctx->flags & PARSE_OPT_STOP_AT_NON_OPTION)
+				break;
+			ctx->out[ctx->cpidx++] = ctx->argv[0];
+			continue;
+		}
+
+		if (arg[1] != '-') {
+			ctx->opt = ++arg;
+			if (internal_help && *ctx->opt == 'h') {
+				return usage_with_options_internal(usagestr, options, 0, ctx);
+			}
+			switch (parse_short_opt(ctx, options)) {
+			case -1:
+				return parse_options_usage(usagestr, options, arg, 1);
+			case -2:
+				goto unknown;
+			case -3:
+				goto exclusive;
+			default:
+				break;
+			}
+			if (ctx->opt)
+				check_typos(arg, options);
+			while (ctx->opt) {
+				if (internal_help && *ctx->opt == 'h')
+					return usage_with_options_internal(usagestr, options, 0, ctx);
+				arg = ctx->opt;
+				switch (parse_short_opt(ctx, options)) {
+				case -1:
+					return parse_options_usage(usagestr, options, arg, 1);
+				case -2:
+					/* fake a short option thing to hide the fact that we may have
+					 * started to parse aggregated stuff
+					 *
+					 * This is leaky, too bad.
+					 */
+					ctx->argv[0] = strdup(ctx->opt - 1);
+					*(char *)ctx->argv[0] = '-';
+					goto unknown;
+				case -3:
+					goto exclusive;
+				default:
+					break;
+				}
+			}
+			continue;
+		}
+
+		if (!arg[2]) { /* "--" */
+			if (!(ctx->flags & PARSE_OPT_KEEP_DASHDASH)) {
+				ctx->argc--;
+				ctx->argv++;
+			}
+			break;
+		}
+
+		arg += 2;
+		if (internal_help && !strcmp(arg, "help-all"))
+			return usage_with_options_internal(usagestr, options, 1, ctx);
+		if (internal_help && !strcmp(arg, "help"))
+			return usage_with_options_internal(usagestr, options, 0, ctx);
+		if (!strcmp(arg, "list-opts"))
+			return PARSE_OPT_LIST_OPTS;
+		if (!strcmp(arg, "list-cmds"))
+			return PARSE_OPT_LIST_SUBCMDS;
+		switch (parse_long_opt(ctx, arg, options)) {
+		case -1:
+			return parse_options_usage(usagestr, options, arg, 0);
+		case -2:
+			goto unknown;
+		case -3:
+			excl_short_opt = 0;
+			goto exclusive;
+		default:
+			break;
+		}
+		continue;
+unknown:
+		if (!(ctx->flags & PARSE_OPT_KEEP_UNKNOWN))
+			return PARSE_OPT_UNKNOWN;
+		ctx->out[ctx->cpidx++] = ctx->argv[0];
+		ctx->opt = NULL;
+	}
+	return PARSE_OPT_DONE;
+
+exclusive:
+	parse_options_usage(usagestr, options, arg, excl_short_opt);
+	if ((excl_short_opt && ctx->excl_opt->short_name) ||
+	    ctx->excl_opt->long_name == NULL) {
+		char opt = ctx->excl_opt->short_name;
+		parse_options_usage(NULL, options, &opt, 1);
+	} else {
+		parse_options_usage(NULL, options, ctx->excl_opt->long_name, 0);
+	}
+	return PARSE_OPT_HELP;
+}
+
+static int parse_options_end(struct parse_opt_ctx_t *ctx)
+{
+	memmove(ctx->out + ctx->cpidx, ctx->argv, ctx->argc * sizeof(*ctx->out));
+	ctx->out[ctx->cpidx + ctx->argc] = NULL;
+	return ctx->cpidx + ctx->argc;
+}
+
+int parse_options_subcommand(int argc, const char **argv, const struct option *options,
+			const char *const subcommands[], const char *usagestr[], int flags)
+{
+	struct parse_opt_ctx_t ctx;
+
+	/* build usage string if it's not provided */
+	if (subcommands && !usagestr[0]) {
+		char *buf = NULL;
+
+		astrcatf(&buf, "%s %s [<options>] {", subcmd_config.exec_name, argv[0]);
+
+		for (int i = 0; subcommands[i]; i++) {
+			if (i)
+				astrcat(&buf, "|");
+			astrcat(&buf, subcommands[i]);
+		}
+		astrcat(&buf, "}");
+
+		usagestr[0] = buf;
+	}
+
+	parse_options_start(&ctx, argc, argv, flags);
+	switch (parse_options_step(&ctx, options, usagestr)) {
+	case PARSE_OPT_HELP:
+		exit(129);
+	case PARSE_OPT_DONE:
+		break;
+	case PARSE_OPT_LIST_OPTS:
+		while (options->type != OPTION_END) {
+			if (options->long_name)
+				printf("--%s ", options->long_name);
+			options++;
+		}
+		putchar('\n');
+		exit(130);
+	case PARSE_OPT_LIST_SUBCMDS:
+		if (subcommands) {
+			for (int i = 0; subcommands[i]; i++)
+				printf("%s ", subcommands[i]);
+		}
+		putchar('\n');
+		exit(130);
+	default: /* PARSE_OPT_UNKNOWN */
+		if (ctx.argv[0][1] == '-')
+			astrcatf(&error_buf, "unknown option `%s'",
+				 ctx.argv[0] + 2);
+		else
+			astrcatf(&error_buf, "unknown switch `%c'", *ctx.opt);
+		usage_with_options(usagestr, options);
+	}
+
+	return parse_options_end(&ctx);
+}
+
+int parse_options(int argc, const char **argv, const struct option *options,
+		  const char * const usagestr[], int flags)
+{
+	return parse_options_subcommand(argc, argv, options, NULL,
+					(const char **) usagestr, flags);
+}
+
+#define USAGE_OPTS_WIDTH 24
+#define USAGE_GAP         2
+
+static void print_option_help(const struct option *opts, int full)
+{
+	size_t pos;
+	int pad;
+
+	if (opts->type == OPTION_GROUP) {
+		fputc('\n', stderr);
+		if (*opts->help)
+			fprintf(stderr, "%s\n", opts->help);
+		return;
+	}
+	if (!full && (opts->flags & PARSE_OPT_HIDDEN))
+		return;
+	if (opts->flags & PARSE_OPT_DISABLED)
+		return;
+
+	pos = fprintf(stderr, "    ");
+	if (opts->short_name)
+		pos += fprintf(stderr, "-%c", opts->short_name);
+	else
+		pos += fprintf(stderr, "    ");
+
+	if (opts->long_name && opts->short_name)
+		pos += fprintf(stderr, ", ");
+	if (opts->long_name)
+		pos += fprintf(stderr, "--%s", opts->long_name);
+
+	switch (opts->type) {
+	case OPTION_ARGUMENT:
+		break;
+	case OPTION_LONG:
+	case OPTION_ULONG:
+	case OPTION_U64:
+	case OPTION_INTEGER:
+	case OPTION_UINTEGER:
+		if (opts->flags & PARSE_OPT_OPTARG)
+			if (opts->long_name)
+				pos += fprintf(stderr, "[=<n>]");
+			else
+				pos += fprintf(stderr, "[<n>]");
+		else
+			pos += fprintf(stderr, " <n>");
+		break;
+	case OPTION_CALLBACK:
+		if (opts->flags & PARSE_OPT_NOARG)
+			break;
+		/* FALLTHROUGH */
+	case OPTION_STRING:
+		if (opts->argh) {
+			if (opts->flags & PARSE_OPT_OPTARG)
+				if (opts->long_name)
+					pos += fprintf(stderr, "[=<%s>]", opts->argh);
+				else
+					pos += fprintf(stderr, "[<%s>]", opts->argh);
+			else
+				pos += fprintf(stderr, " <%s>", opts->argh);
+		} else {
+			if (opts->flags & PARSE_OPT_OPTARG)
+				if (opts->long_name)
+					pos += fprintf(stderr, "[=...]");
+				else
+					pos += fprintf(stderr, "[...]");
+			else
+				pos += fprintf(stderr, " ...");
+		}
+		break;
+	default: /* OPTION_{BIT,BOOLEAN,SET_UINT,SET_PTR} */
+	case OPTION_END:
+	case OPTION_GROUP:
+	case OPTION_BIT:
+	case OPTION_BOOLEAN:
+	case OPTION_INCR:
+	case OPTION_SET_UINT:
+	case OPTION_SET_PTR:
+		break;
+	}
+
+	if (pos <= USAGE_OPTS_WIDTH)
+		pad = USAGE_OPTS_WIDTH - pos;
+	else {
+		fputc('\n', stderr);
+		pad = USAGE_OPTS_WIDTH;
+	}
+	fprintf(stderr, "%*s%s\n", pad + USAGE_GAP, "", opts->help);
+	if (opts->flags & PARSE_OPT_NOBUILD)
+		fprintf(stderr, "%*s(not built-in because %s)\n",
+			USAGE_OPTS_WIDTH + USAGE_GAP, "",
+			opts->build_opt);
+}
+
+static int option__cmp(const void *va, const void *vb)
+{
+	const struct option *a = va, *b = vb;
+	int sa = tolower(a->short_name), sb = tolower(b->short_name), ret;
+
+	if (sa == 0)
+		sa = 'z' + 1;
+	if (sb == 0)
+		sb = 'z' + 1;
+
+	ret = sa - sb;
+
+	if (ret == 0) {
+		const char *la = a->long_name ?: "",
+			   *lb = b->long_name ?: "";
+		ret = strcmp(la, lb);
+	}
+
+	return ret;
+}
+
+static struct option *options__order(const struct option *opts)
+{
+	int nr_opts = 0, nr_group = 0, nr_parent = 0, len;
+	const struct option *o = NULL, *p = opts;
+	struct option *opt, *ordered = NULL, *group;
+
+	/* flatten the options that have parents */
+	for (p = opts; p != NULL; p = o->parent) {
+		for (o = p; o->type != OPTION_END; o++)
+			++nr_opts;
+
+		/*
+		 * the length is given by the number of options plus a null
+		 * terminator for the last loop iteration.
+		 */
+		len = sizeof(*o) * (nr_opts + !o->parent);
+		group = realloc(ordered, len);
+		if (!group)
+			goto out;
+		ordered = group;
+		memcpy(&ordered[nr_parent], p, sizeof(*o) * (nr_opts - nr_parent));
+
+		nr_parent = nr_opts;
+	}
+	/* copy the last OPTION_END */
+	memcpy(&ordered[nr_opts], o, sizeof(*o));
+
+	/* sort each option group individually */
+	for (opt = group = ordered; opt->type != OPTION_END; opt++) {
+		if (opt->type == OPTION_GROUP) {
+			qsort(group, nr_group, sizeof(*opt), option__cmp);
+			group = opt + 1;
+			nr_group = 0;
+			continue;
+		}
+		nr_group++;
+	}
+	qsort(group, nr_group, sizeof(*opt), option__cmp);
+
+out:
+	return ordered;
+}
+
+static bool option__in_argv(const struct option *opt, const struct parse_opt_ctx_t *ctx)
+{
+	int i;
+
+	for (i = 1; i < ctx->argc; ++i) {
+		const char *arg = ctx->argv[i];
+
+		if (arg[0] != '-') {
+			if (arg[1] == '\0') {
+				if (arg[0] == opt->short_name)
+					return true;
+				continue;
+			}
+
+			if (opt->long_name && strcmp(opt->long_name, arg) == 0)
+				return true;
+
+			if (opt->help && strcasestr(opt->help, arg) != NULL)
+				return true;
+
+			continue;
+		}
+
+		if (arg[1] == opt->short_name ||
+		    (arg[1] == '-' && opt->long_name && strcmp(opt->long_name, arg + 2) == 0))
+			return true;
+	}
+
+	return false;
+}
+
+static int usage_with_options_internal(const char * const *usagestr,
+				       const struct option *opts, int full,
+				       struct parse_opt_ctx_t *ctx)
+{
+	struct option *ordered;
+
+	if (!usagestr)
+		return PARSE_OPT_HELP;
+
+	setup_pager();
+
+	if (error_buf) {
+		fprintf(stderr, "  Error: %s\n", error_buf);
+		zfree(&error_buf);
+	}
+
+	fprintf(stderr, "\n Usage: %s\n", *usagestr++);
+	while (*usagestr && **usagestr)
+		fprintf(stderr, "    or: %s\n", *usagestr++);
+	while (*usagestr) {
+		fprintf(stderr, "%s%s\n",
+				**usagestr ? "    " : "",
+				*usagestr);
+		usagestr++;
+	}
+
+	if (opts->type != OPTION_GROUP)
+		fputc('\n', stderr);
+
+	ordered = options__order(opts);
+	if (ordered)
+		opts = ordered;
+
+	for (  ; opts->type != OPTION_END; opts++) {
+		if (ctx && ctx->argc > 1 && !option__in_argv(opts, ctx))
+			continue;
+		print_option_help(opts, full);
+	}
+
+	fputc('\n', stderr);
+
+	free(ordered);
+
+	return PARSE_OPT_HELP;
+}
+
+void usage_with_options(const char * const *usagestr,
+			const struct option *opts)
+{
+	usage_with_options_internal(usagestr, opts, 0, NULL);
+	exit(129);
+}
+
+void usage_with_options_msg(const char * const *usagestr,
+			    const struct option *opts, const char *fmt, ...)
+{
+	va_list ap;
+	char *tmp = error_buf;
+
+	va_start(ap, fmt);
+	if (vasprintf(&error_buf, fmt, ap) == -1)
+		die("vasprintf failed");
+	va_end(ap);
+
+	free(tmp);
+
+	usage_with_options_internal(usagestr, opts, 0, NULL);
+	exit(129);
+}
+
+int parse_options_usage(const char * const *usagestr,
+			const struct option *opts,
+			const char *optstr, bool short_opt)
+{
+	if (!usagestr)
+		goto opt;
+
+	fprintf(stderr, "\n Usage: %s\n", *usagestr++);
+	while (*usagestr && **usagestr)
+		fprintf(stderr, "    or: %s\n", *usagestr++);
+	while (*usagestr) {
+		fprintf(stderr, "%s%s\n",
+				**usagestr ? "    " : "",
+				*usagestr);
+		usagestr++;
+	}
+	fputc('\n', stderr);
+
+opt:
+	for (  ; opts->type != OPTION_END; opts++) {
+		if (short_opt) {
+			if (opts->short_name == *optstr) {
+				print_option_help(opts, 0);
+				break;
+			}
+			continue;
+		}
+
+		if (opts->long_name == NULL)
+			continue;
+
+		if (strstarts(opts->long_name, optstr))
+			print_option_help(opts, 0);
+		if (strstarts("no-", optstr) &&
+		    strstarts(opts->long_name, optstr + 3) &&
+			!(opts->flags & PARSE_OPT_NOAUTONEG))
+			print_option_help(opts, 0);
+	}
+
+	return PARSE_OPT_HELP;
+}
+
+
+int parse_opt_verbosity_cb(const struct option *opt,
+			   const char *arg __maybe_unused,
+			   int unset)
+{
+	int *target = opt->value;
+
+	if (unset)
+		/* --no-quiet, --no-verbose */
+		*target = 0;
+	else if (opt->short_name == 'v') {
+		if (*target >= 0)
+			(*target)++;
+		else
+			*target = 1;
+	} else {
+		if (*target <= 0)
+			(*target)--;
+		else
+			*target = -1;
+	}
+	return 0;
+}
+
+static struct option *
+find_option(struct option *opts, int shortopt, const char *longopt)
+{
+	for (; opts->type != OPTION_END; opts++) {
+		if ((shortopt && opts->short_name == shortopt) ||
+		    (opts->long_name && longopt &&
+		     !strcmp(opts->long_name, longopt)))
+			return opts;
+	}
+	return NULL;
+}
+
+void set_option_flag(struct option *opts, int shortopt, const char *longopt,
+		     int flag)
+{
+	struct option *opt = find_option(opts, shortopt, longopt);
+
+	if (opt)
+		opt->flags |= flag;
+	return;
+}
+
+void set_option_nobuild(struct option *opts, int shortopt,
+			const char *longopt,
+			const char *build_opt,
+			bool can_skip)
+{
+	struct option *opt = find_option(opts, shortopt, longopt);
+
+	if (!opt)
+		return;
+
+	opt->flags |= PARSE_OPT_NOBUILD;
+	opt->flags |= can_skip ? PARSE_OPT_CANSKIP : 0;
+	opt->build_opt = build_opt;
+}
diff --git a/tools/lib/subcmd/parse-options.h b/tools/lib/subcmd/parse-options.h
new file mode 100644
index 000000000..38df5fd21
--- /dev/null
+++ b/tools/lib/subcmd/parse-options.h
@@ -0,0 +1,247 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_PARSE_OPTIONS_H
+#define __SUBCMD_PARSE_OPTIONS_H
+
+#include <linux/kernel.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+enum parse_opt_type {
+	/* special types */
+	OPTION_END,
+	OPTION_ARGUMENT,
+	OPTION_GROUP,
+	/* options with no arguments */
+	OPTION_BIT,
+	OPTION_BOOLEAN,
+	OPTION_INCR,
+	OPTION_SET_UINT,
+	OPTION_SET_PTR,
+	/* options with arguments (usually) */
+	OPTION_STRING,
+	OPTION_INTEGER,
+	OPTION_LONG,
+	OPTION_ULONG,
+	OPTION_CALLBACK,
+	OPTION_U64,
+	OPTION_UINTEGER,
+};
+
+enum parse_opt_flags {
+	PARSE_OPT_KEEP_DASHDASH = 1,
+	PARSE_OPT_STOP_AT_NON_OPTION = 2,
+	PARSE_OPT_KEEP_ARGV0 = 4,
+	PARSE_OPT_KEEP_UNKNOWN = 8,
+	PARSE_OPT_NO_INTERNAL_HELP = 16,
+	PARSE_OPT_OPTARG_ALLOW_NEXT = 32,
+};
+
+enum parse_opt_option_flags {
+	PARSE_OPT_OPTARG  = 1,
+	PARSE_OPT_NOARG   = 2,
+	PARSE_OPT_NONEG   = 4,
+	PARSE_OPT_HIDDEN  = 8,
+	PARSE_OPT_LASTARG_DEFAULT = 16,
+	PARSE_OPT_DISABLED = 32,
+	PARSE_OPT_EXCLUSIVE = 64,
+	PARSE_OPT_NOEMPTY  = 128,
+	PARSE_OPT_NOBUILD  = 256,
+	PARSE_OPT_CANSKIP  = 512,
+	PARSE_OPT_NOAUTONEG = 1024,
+};
+
+struct option;
+typedef int parse_opt_cb(const struct option *, const char *arg, int unset);
+
+/*
+ * `type`::
+ *   holds the type of the option, you must have an OPTION_END last in your
+ *   array.
+ *
+ * `short_name`::
+ *   the character to use as a short option name, '\0' if none.
+ *
+ * `long_name`::
+ *   the long option name, without the leading dashes, NULL if none.
+ *
+ * `value`::
+ *   stores pointers to the values to be filled.
+ *
+ * `argh`::
+ *   token to explain the kind of argument this option wants. Keep it
+ *   homogeneous across the repository.
+ *
+ * `help`::
+ *   the short help associated to what the option does.
+ *   Must never be NULL (except for OPTION_END).
+ *   OPTION_GROUP uses this pointer to store the group header.
+ *
+ * `flags`::
+ *   mask of parse_opt_option_flags.
+ *   PARSE_OPT_OPTARG: says that the argument is optional (not for BOOLEANs)
+ *   PARSE_OPT_NOARG: says that this option takes no argument, for CALLBACKs
+ *   PARSE_OPT_NONEG: says that this option cannot be negated
+ *   PARSE_OPT_HIDDEN this option is skipped in the default usage, showed in
+ *                    the long one.
+ *
+ * `callback`::
+ *   pointer to the callback to use for OPTION_CALLBACK.
+ *
+ * `defval`::
+ *   default value to fill (*->value) with for PARSE_OPT_OPTARG.
+ *   OPTION_{BIT,SET_UINT,SET_PTR} store the {mask,integer,pointer} to put in
+ *   the value when met.
+ *   CALLBACKS can use it like they want.
+ *
+ * `set`::
+ *   whether an option was set by the user
+ */
+struct option {
+	enum parse_opt_type type;
+	int short_name;
+	const char *long_name;
+	void *value;
+	const char *argh;
+	const char *help;
+	const char *build_opt;
+
+	int flags;
+	parse_opt_cb *callback;
+	intptr_t defval;
+	bool *set;
+	void *data;
+	const struct option *parent;
+};
+
+#define check_vtype(v, type) ( BUILD_BUG_ON_ZERO(!__builtin_types_compatible_p(typeof(v), type)) + v )
+
+#define OPT_END()                   { .type = OPTION_END }
+#define OPT_PARENT(p)               { .type = OPTION_END, .parent = (p) }
+#define OPT_ARGUMENT(l, h)          { .type = OPTION_ARGUMENT, .long_name = (l), .help = (h) }
+#define OPT_GROUP(h)                { .type = OPTION_GROUP, .help = (h) }
+#define OPT_BIT(s, l, v, h, b)      { .type = OPTION_BIT, .short_name = (s), .long_name = (l), .value = check_vtype(v, int *), .help = (h), .defval = (b) }
+#define OPT_BOOLEAN(s, l, v, h)     { .type = OPTION_BOOLEAN, .short_name = (s), .long_name = (l), .value = check_vtype(v, bool *), .help = (h) }
+#define OPT_BOOLEAN_FLAG(s, l, v, h, f)     { .type = OPTION_BOOLEAN, .short_name = (s), .long_name = (l), .value = check_vtype(v, bool *), .help = (h), .flags = (f) }
+#define OPT_BOOLEAN_SET(s, l, v, os, h) \
+	{ .type = OPTION_BOOLEAN, .short_name = (s), .long_name = (l), \
+	.value = check_vtype(v, bool *), .help = (h), \
+	.set = check_vtype(os, bool *)}
+#define OPT_INCR(s, l, v, h)        { .type = OPTION_INCR, .short_name = (s), .long_name = (l), .value = check_vtype(v, int *), .help = (h) }
+#define OPT_SET_UINT(s, l, v, h, i)  { .type = OPTION_SET_UINT, .short_name = (s), .long_name = (l), .value = check_vtype(v, unsigned int *), .help = (h), .defval = (i) }
+#define OPT_SET_PTR(s, l, v, h, p)  { .type = OPTION_SET_PTR, .short_name = (s), .long_name = (l), .value = (v), .help = (h), .defval = (p) }
+#define OPT_INTEGER(s, l, v, h)     { .type = OPTION_INTEGER, .short_name = (s), .long_name = (l), .value = check_vtype(v, int *), .help = (h) }
+#define OPT_UINTEGER(s, l, v, h)    { .type = OPTION_UINTEGER, .short_name = (s), .long_name = (l), .value = check_vtype(v, unsigned int *), .help = (h) }
+#define OPT_UINTEGER_OPTARG(s, l, v, d, h)    { .type = OPTION_UINTEGER, .short_name = (s), .long_name = (l), .value = check_vtype(v, unsigned int *), .help = (h), .flags = PARSE_OPT_OPTARG, .defval = (intptr_t)(d) }
+#define OPT_LONG(s, l, v, h)        { .type = OPTION_LONG, .short_name = (s), .long_name = (l), .value = check_vtype(v, long *), .help = (h) }
+#define OPT_ULONG(s, l, v, h)        { .type = OPTION_ULONG, .short_name = (s), .long_name = (l), .value = check_vtype(v, unsigned long *), .help = (h) }
+#define OPT_U64(s, l, v, h)         { .type = OPTION_U64, .short_name = (s), .long_name = (l), .value = check_vtype(v, u64 *), .help = (h) }
+#define OPT_STRING(s, l, v, a, h)   { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), .value = check_vtype(v, const char **), .argh = (a), .help = (h) }
+#define OPT_STRING_OPTARG(s, l, v, a, h, d) \
+	{ .type = OPTION_STRING,  .short_name = (s), .long_name = (l), \
+	  .value = check_vtype(v, const char **), .argh =(a), .help = (h), \
+	  .flags = PARSE_OPT_OPTARG, .defval = (intptr_t)(d) }
+#define OPT_STRING_OPTARG_SET(s, l, v, os, a, h, d) \
+	{ .type = OPTION_STRING, .short_name = (s), .long_name = (l), \
+	  .value = check_vtype(v, const char **), .argh = (a), .help = (h), \
+	  .flags = PARSE_OPT_OPTARG, .defval = (intptr_t)(d), \
+	  .set = check_vtype(os, bool *)}
+#define OPT_STRING_NOEMPTY(s, l, v, a, h)   { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), .value = check_vtype(v, const char **), .argh = (a), .help = (h), .flags = PARSE_OPT_NOEMPTY}
+#define OPT_DATE(s, l, v, h) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = "time", .help = (h), .callback = parse_opt_approxidate_cb }
+#define OPT_CALLBACK(s, l, v, a, h, f) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = (a), .help = (h), .callback = (f) }
+#define OPT_CALLBACK_FLAG(s, l, v, a, h, f, fl) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = (a), .help = (h), .callback = (f), .flags = (fl) }
+#define OPT_CALLBACK_SET(s, l, v, os, a, h, f) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = (a), .help = (h), .callback = (f), .set = check_vtype(os, bool *)}
+#define OPT_CALLBACK_NOOPT(s, l, v, a, h, f) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = (a), .help = (h), .callback = (f), .flags = PARSE_OPT_NOARG }
+#define OPT_CALLBACK_DEFAULT(s, l, v, a, h, f, d) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = (a), .help = (h), .callback = (f), .defval = (intptr_t)d, .flags = PARSE_OPT_LASTARG_DEFAULT }
+#define OPT_CALLBACK_DEFAULT_NOOPT(s, l, v, a, h, f, d) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),\
+	.value = (v), .arg = (a), .help = (h), .callback = (f), .defval = (intptr_t)d,\
+	.flags = PARSE_OPT_LASTARG_DEFAULT | PARSE_OPT_NOARG}
+#define OPT_CALLBACK_OPTARG(s, l, v, d, a, h, f) \
+	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), \
+	  .value = (v), .argh = (a), .help = (h), .callback = (f), \
+	  .flags = PARSE_OPT_OPTARG, .data = (d) }
+
+/* parse_options() will filter out the processed options and leave the
+ * non-option argments in argv[].
+ * Returns the number of arguments left in argv[].
+ *
+ * NOTE: parse_options() and parse_options_subcommand() may call exit() in the
+ * case of an error (or for 'special' options like --list-cmds or --list-opts).
+ */
+extern int parse_options(int argc, const char **argv,
+                         const struct option *options,
+                         const char * const usagestr[], int flags);
+
+extern int parse_options_subcommand(int argc, const char **argv,
+				const struct option *options,
+				const char *const subcommands[],
+				const char *usagestr[], int flags);
+
+extern __noreturn void usage_with_options(const char * const *usagestr,
+                                        const struct option *options);
+extern __noreturn __attribute__((format(printf,3,4)))
+void usage_with_options_msg(const char * const *usagestr,
+			    const struct option *options,
+			    const char *fmt, ...);
+
+/*----- incremantal advanced APIs -----*/
+
+enum {
+	PARSE_OPT_HELP = -1,
+	PARSE_OPT_DONE,
+	PARSE_OPT_LIST_OPTS,
+	PARSE_OPT_LIST_SUBCMDS,
+	PARSE_OPT_UNKNOWN,
+};
+
+/*
+ * It's okay for the caller to consume argv/argc in the usual way.
+ * Other fields of that structure are private to parse-options and should not
+ * be modified in any way.
+ */
+struct parse_opt_ctx_t {
+	const char **argv;
+	const char **out;
+	int argc, cpidx;
+	const char *opt;
+	const struct option *excl_opt;
+	int flags;
+};
+
+extern int parse_options_usage(const char * const *usagestr,
+			       const struct option *opts,
+			       const char *optstr,
+			       bool short_opt);
+
+
+/*----- some often used options -----*/
+extern int parse_opt_abbrev_cb(const struct option *, const char *, int);
+extern int parse_opt_approxidate_cb(const struct option *, const char *, int);
+extern int parse_opt_verbosity_cb(const struct option *, const char *, int);
+
+#define OPT__VERBOSE(var)  OPT_BOOLEAN('v', "verbose", (var), "be verbose")
+#define OPT__QUIET(var)    OPT_BOOLEAN('q', "quiet",   (var), "be quiet")
+#define OPT__VERBOSITY(var) \
+	{ OPTION_CALLBACK, 'v', "verbose", (var), NULL, "be more verbose", \
+	  PARSE_OPT_NOARG, &parse_opt_verbosity_cb, 0 }, \
+	{ OPTION_CALLBACK, 'q', "quiet", (var), NULL, "be more quiet", \
+	  PARSE_OPT_NOARG, &parse_opt_verbosity_cb, 0 }
+#define OPT__DRY_RUN(var)  OPT_BOOLEAN('n', "dry-run", (var), "dry run")
+#define OPT__ABBREV(var)  \
+	{ OPTION_CALLBACK, 0, "abbrev", (var), "n", \
+	  "use <n> digits to display SHA-1s", \
+	  PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
+
+extern const char *parse_options_fix_filename(const char *prefix, const char *file);
+
+void set_option_flag(struct option *opts, int sopt, const char *lopt, int flag);
+void set_option_nobuild(struct option *opts, int shortopt, const char *longopt,
+			const char *build_opt, bool can_skip);
+
+#endif /* __SUBCMD_PARSE_OPTIONS_H */
diff --git a/tools/lib/subcmd/run-command.c b/tools/lib/subcmd/run-command.c
new file mode 100644
index 000000000..bd21b8bfd
--- /dev/null
+++ b/tools/lib/subcmd/run-command.c
@@ -0,0 +1,358 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/compiler.h>
+#include <linux/string.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include "subcmd-util.h"
+#include "run-command.h"
+#include "exec-cmd.h"
+
+#define STRERR_BUFSIZE 128
+
+static inline void close_pair(int fd[2])
+{
+	close(fd[0]);
+	close(fd[1]);
+}
+
+static inline void dup_devnull(int to)
+{
+	int fd = open("/dev/null", O_RDWR);
+	dup2(fd, to);
+	close(fd);
+}
+
+int start_command(struct child_process *cmd)
+{
+	int need_in, need_out, need_err;
+	int fdin[2], fdout[2], fderr[2];
+	char sbuf[STRERR_BUFSIZE];
+
+	/*
+	 * In case of errors we must keep the promise to close FDs
+	 * that have been passed in via ->in and ->out.
+	 */
+
+	need_in = !cmd->no_stdin && cmd->in < 0;
+	if (need_in) {
+		if (pipe(fdin) < 0) {
+			if (cmd->out > 0)
+				close(cmd->out);
+			return -ERR_RUN_COMMAND_PIPE;
+		}
+		cmd->in = fdin[1];
+	}
+
+	need_out = !cmd->no_stdout
+		&& !cmd->stdout_to_stderr
+		&& cmd->out < 0;
+	if (need_out) {
+		if (pipe(fdout) < 0) {
+			if (need_in)
+				close_pair(fdin);
+			else if (cmd->in)
+				close(cmd->in);
+			return -ERR_RUN_COMMAND_PIPE;
+		}
+		cmd->out = fdout[0];
+	}
+
+	need_err = !cmd->no_stderr && cmd->err < 0;
+	if (need_err) {
+		if (pipe(fderr) < 0) {
+			if (need_in)
+				close_pair(fdin);
+			else if (cmd->in)
+				close(cmd->in);
+			if (need_out)
+				close_pair(fdout);
+			else if (cmd->out)
+				close(cmd->out);
+			return -ERR_RUN_COMMAND_PIPE;
+		}
+		cmd->err = fderr[0];
+	}
+
+	fflush(NULL);
+	cmd->pid = fork();
+	if (!cmd->pid) {
+		if (cmd->no_stdin)
+			dup_devnull(0);
+		else if (need_in) {
+			dup2(fdin[0], 0);
+			close_pair(fdin);
+		} else if (cmd->in) {
+			dup2(cmd->in, 0);
+			close(cmd->in);
+		}
+
+		if (cmd->no_stderr)
+			dup_devnull(2);
+		else if (need_err) {
+			dup2(fderr[1], 2);
+			close_pair(fderr);
+		}
+
+		if (cmd->no_stdout)
+			dup_devnull(1);
+		else if (cmd->stdout_to_stderr)
+			dup2(2, 1);
+		else if (need_out) {
+			dup2(fdout[1], 1);
+			close_pair(fdout);
+		} else if (cmd->out > 1) {
+			dup2(cmd->out, 1);
+			close(cmd->out);
+		}
+
+		if (cmd->dir && chdir(cmd->dir))
+			die("exec %s: cd to %s failed (%s)", cmd->argv[0],
+			    cmd->dir, str_error_r(errno, sbuf, sizeof(sbuf)));
+		if (cmd->env) {
+			for (; *cmd->env; cmd->env++) {
+				if (strchr(*cmd->env, '='))
+					putenv((char*)*cmd->env);
+				else
+					unsetenv(*cmd->env);
+			}
+		}
+		if (cmd->preexec_cb)
+			cmd->preexec_cb();
+		if (cmd->no_exec_cmd)
+			exit(cmd->no_exec_cmd(cmd));
+		if (cmd->exec_cmd) {
+			execv_cmd(cmd->argv);
+		} else {
+			execvp(cmd->argv[0], (char *const*) cmd->argv);
+		}
+		exit(127);
+	}
+
+	if (cmd->pid < 0) {
+		int err = errno;
+		if (need_in)
+			close_pair(fdin);
+		else if (cmd->in)
+			close(cmd->in);
+		if (need_out)
+			close_pair(fdout);
+		else if (cmd->out)
+			close(cmd->out);
+		if (need_err)
+			close_pair(fderr);
+		return err == ENOENT ?
+			-ERR_RUN_COMMAND_EXEC :
+			-ERR_RUN_COMMAND_FORK;
+	}
+
+	if (need_in)
+		close(fdin[0]);
+	else if (cmd->in)
+		close(cmd->in);
+
+	if (need_out)
+		close(fdout[1]);
+	else if (cmd->out)
+		close(cmd->out);
+
+	if (need_err)
+		close(fderr[1]);
+
+	return 0;
+}
+
+static int wait_or_whine(struct child_process *cmd, bool block)
+{
+	bool finished;
+	int result;
+
+	if (cmd->pid <= 0) {
+		cmd->finished = 1;
+		if (cmd->pid < 0 && cmd->finish_result == 0)
+			cmd->finish_result = -ERR_RUN_COMMAND_FORK;
+		return cmd->finish_result;
+	}
+
+	finished = cmd->finished;
+	result = cmd->finish_result;
+
+	while (!finished) {
+		int status, code;
+		pid_t waiting = waitpid(cmd->pid, &status, block ? 0 : WNOHANG);
+
+		if (!block && waiting == 0)
+			break;
+
+		if (waiting < 0 && errno == EINTR)
+			continue;
+
+		finished = true;
+		if (waiting < 0) {
+			char sbuf[STRERR_BUFSIZE];
+
+			fprintf(stderr, " Error: waitpid failed (%s)",
+				str_error_r(errno, sbuf, sizeof(sbuf)));
+			result = -ERR_RUN_COMMAND_WAITPID;
+		} else if (waiting != cmd->pid) {
+			result = -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
+		} else if (WIFSIGNALED(status)) {
+			result = -ERR_RUN_COMMAND_WAITPID_SIGNAL;
+		} else if (!WIFEXITED(status)) {
+			result = -ERR_RUN_COMMAND_WAITPID_NOEXIT;
+		} else {
+			code = WEXITSTATUS(status);
+			switch (code) {
+			case 127:
+				result = -ERR_RUN_COMMAND_EXEC;
+				break;
+			case 0:
+				result = 0;
+				break;
+			default:
+				result = -code;
+				break;
+			}
+		}
+	}
+	if (finished) {
+		cmd->finished = 1;
+		cmd->finish_result = result;
+	}
+	return result;
+}
+
+/*
+ * Conservative estimate of number of characaters needed to hold an a decoded
+ * integer, assume each 3 bits needs a character byte and plus a possible sign
+ * character.
+ */
+#ifndef is_signed_type
+#define is_signed_type(type) (((type)(-1)) < (type)1)
+#endif
+#define MAX_STRLEN_TYPE(type) (sizeof(type) * 8 / 3 + (is_signed_type(type) ? 1 : 0))
+
+int check_if_command_finished(struct child_process *cmd)
+{
+#ifdef __linux__
+	char filename[6 + MAX_STRLEN_TYPE(typeof(cmd->pid)) + 7 + 1];
+	char status_line[256];
+	FILE *status_file;
+#endif
+
+	if (cmd->finished)
+		return 1;
+	if (cmd->pid <= 0) {
+		cmd->finished = 1;
+		if (cmd->pid < 0 && cmd->finish_result == 0)
+			cmd->finish_result = -ERR_RUN_COMMAND_FORK;
+		return 1;
+	}
+
+#ifdef __linux__
+	/*
+	 * Check by reading /proc/<pid>/status as calling waitpid causes
+	 * stdout/stderr to be closed and data lost.
+	 */
+	sprintf(filename, "/proc/%u/status", cmd->pid);
+	status_file = fopen(filename, "r");
+	if (status_file == NULL) {
+		int status;
+		pid_t waiting;
+
+		/*
+		 * fopen() can fail with ENOENT if the process has been reaped.
+		 * It can also fail with EMFILE/ENFILE if RLIMIT_NOFILE is reached.
+		 * In those cases, use waitpid(..., WNOHANG) to robustly check
+		 * and reap the process if it has exited.
+		 */
+		if (errno == ENOENT)
+			return 1;
+
+		waiting = waitpid(cmd->pid, &status, WNOHANG);
+		if (waiting == cmd->pid) {
+			int result;
+			int code;
+
+			cmd->finished = 1;
+			if (WIFSIGNALED(status)) {
+				result = -ERR_RUN_COMMAND_WAITPID_SIGNAL;
+			} else if (!WIFEXITED(status)) {
+				result = -ERR_RUN_COMMAND_WAITPID_NOEXIT;
+			} else {
+				code = WEXITSTATUS(status);
+				switch (code) {
+				case 127:
+					result = -ERR_RUN_COMMAND_EXEC;
+					break;
+				case 0:
+					result = 0;
+					break;
+				default:
+					result = -code;
+					break;
+				}
+			}
+			cmd->finish_result = result;
+			return 1;
+		}
+		if (waiting < 0 && (errno == ECHILD || errno == ESRCH))
+			return 1;
+		return 0;
+	}
+	while (fgets(status_line, sizeof(status_line), status_file) != NULL) {
+		char *p;
+
+		if (strncmp(status_line, "State:", 6))
+			continue;
+
+		fclose(status_file);
+		p = status_line + 6;
+		while (isspace(*p))
+			p++;
+		return *p == 'Z' ? 1 : 0;
+	}
+	/* Read failed assume finish_command was called. */
+	fclose(status_file);
+	return 1;
+#else
+	wait_or_whine(cmd, /*block=*/false);
+	return cmd->finished;
+#endif
+}
+
+int finish_command(struct child_process *cmd)
+{
+	return wait_or_whine(cmd, /*block=*/true);
+}
+
+int run_command(struct child_process *cmd)
+{
+	int code = start_command(cmd);
+	if (code)
+		return code;
+	return finish_command(cmd);
+}
+
+static void prepare_run_command_v_opt(struct child_process *cmd,
+				      const char **argv,
+				      int opt)
+{
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->argv = argv;
+	cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
+	cmd->exec_cmd = opt & RUN_EXEC_CMD ? 1 : 0;
+	cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
+}
+
+int run_command_v_opt(const char **argv, int opt)
+{
+	struct child_process cmd;
+	prepare_run_command_v_opt(&cmd, argv, opt);
+	return run_command(&cmd);
+}
diff --git a/tools/lib/subcmd/run-command.h b/tools/lib/subcmd/run-command.h
new file mode 100644
index 000000000..b2d39de6e
--- /dev/null
+++ b/tools/lib/subcmd/run-command.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_RUN_COMMAND_H
+#define __SUBCMD_RUN_COMMAND_H
+
+#include <unistd.h>
+
+enum {
+	ERR_RUN_COMMAND_FORK = 10000,
+	ERR_RUN_COMMAND_EXEC,
+	ERR_RUN_COMMAND_PIPE,
+	ERR_RUN_COMMAND_WAITPID,
+	ERR_RUN_COMMAND_WAITPID_WRONG_PID,
+	ERR_RUN_COMMAND_WAITPID_SIGNAL,
+	ERR_RUN_COMMAND_WAITPID_NOEXIT,
+};
+#define IS_RUN_COMMAND_ERR(x) (-(x) >= ERR_RUN_COMMAND_FORK)
+
+struct child_process {
+	const char **argv;
+	pid_t pid;
+	/*
+	 * Using .in, .out, .err:
+	 * - Specify 0 for no redirections (child inherits stdin, stdout,
+	 *   stderr from parent).
+	 * - Specify -1 to have a pipe allocated as follows:
+	 *     .in: returns the writable pipe end; parent writes to it,
+	 *          the readable pipe end becomes child's stdin
+	 *     .out, .err: returns the readable pipe end; parent reads from
+	 *          it, the writable pipe end becomes child's stdout/stderr
+	 *   The caller of start_command() must close the returned FDs
+	 *   after it has completed reading from/writing to it!
+	 * - Specify > 0 to set a channel to a particular FD as follows:
+	 *     .in: a readable FD, becomes child's stdin
+	 *     .out: a writable FD, becomes child's stdout/stderr
+	 *     .err > 0 not supported
+	 *   The specified FD is closed by start_command(), even in case
+	 *   of errors!
+	 */
+	int in;
+	int out;
+	int err;
+	const char *dir;
+	const char *const *env;
+	int finish_result;
+	unsigned no_stdin:1;
+	unsigned no_stdout:1;
+	unsigned no_stderr:1;
+	unsigned exec_cmd:1; /* if this is to be external sub-command */
+	unsigned stdout_to_stderr:1;
+	unsigned finished:1;
+	void (*preexec_cb)(void);
+	 /* If set, call function in child rather than doing an exec. */
+	int (*no_exec_cmd)(struct child_process *process);
+};
+
+int start_command(struct child_process *);
+int check_if_command_finished(struct child_process *);
+int finish_command(struct child_process *);
+int run_command(struct child_process *);
+
+#define RUN_COMMAND_NO_STDIN 1
+#define RUN_EXEC_CMD	     2	/*If this is to be external sub-command */
+#define RUN_COMMAND_STDOUT_TO_STDERR 4
+int run_command_v_opt(const char **argv, int opt);
+
+#endif /* __SUBCMD_RUN_COMMAND_H */
diff --git a/tools/lib/subcmd/sigchain.c b/tools/lib/subcmd/sigchain.c
new file mode 100644
index 000000000..f0fe3dbef
--- /dev/null
+++ b/tools/lib/subcmd/sigchain.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <signal.h>
+#include "subcmd-util.h"
+#include "sigchain.h"
+
+#define SIGCHAIN_MAX_SIGNALS 32
+
+struct sigchain_signal {
+	sigchain_fun *old;
+	int n;
+	int alloc;
+};
+static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
+
+static void check_signum(int sig)
+{
+	if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
+		die("BUG: signal out of range: %d", sig);
+}
+
+static int sigchain_push(int sig, sigchain_fun f)
+{
+	struct sigchain_signal *s = signals + sig;
+	check_signum(sig);
+
+	ALLOC_GROW(s->old, s->n + 1, s->alloc);
+	s->old[s->n] = signal(sig, f);
+	if (s->old[s->n] == SIG_ERR)
+		return -1;
+	s->n++;
+	return 0;
+}
+
+int sigchain_pop(int sig)
+{
+	struct sigchain_signal *s = signals + sig;
+	check_signum(sig);
+	if (s->n < 1)
+		return 0;
+
+	if (signal(sig, s->old[s->n - 1]) == SIG_ERR)
+		return -1;
+	s->n--;
+	return 0;
+}
+
+void sigchain_push_common(sigchain_fun f)
+{
+	sigchain_push(SIGINT, f);
+	sigchain_push(SIGHUP, f);
+	sigchain_push(SIGTERM, f);
+	sigchain_push(SIGQUIT, f);
+	sigchain_push(SIGPIPE, f);
+}
diff --git a/tools/lib/subcmd/sigchain.h b/tools/lib/subcmd/sigchain.h
new file mode 100644
index 000000000..1ec663af4
--- /dev/null
+++ b/tools/lib/subcmd/sigchain.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_SIGCHAIN_H
+#define __SUBCMD_SIGCHAIN_H
+
+typedef void (*sigchain_fun)(int);
+
+int sigchain_pop(int sig);
+
+void sigchain_push_common(sigchain_fun f);
+
+#endif /* __SUBCMD_SIGCHAIN_H */
diff --git a/tools/lib/subcmd/subcmd-config.c b/tools/lib/subcmd/subcmd-config.c
new file mode 100644
index 000000000..84a7cf6c7
--- /dev/null
+++ b/tools/lib/subcmd/subcmd-config.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "subcmd-config.h"
+
+#define UNDEFINED "SUBCMD_HAS_NOT_BEEN_INITIALIZED"
+
+struct subcmd_config subcmd_config = {
+	.exec_name	= UNDEFINED,
+	.prefix		= UNDEFINED,
+	.exec_path	= UNDEFINED,
+	.exec_path_env	= UNDEFINED,
+	.pager_env	= UNDEFINED,
+};
diff --git a/tools/lib/subcmd/subcmd-config.h b/tools/lib/subcmd/subcmd-config.h
new file mode 100644
index 000000000..9024dc17d
--- /dev/null
+++ b/tools/lib/subcmd/subcmd-config.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_SUBCMD_CONFIG_H
+#define __PERF_SUBCMD_CONFIG_H
+
+struct subcmd_config {
+	const char *exec_name;
+	const char *prefix;
+	const char *exec_path;
+	const char *exec_path_env;
+	const char *pager_env;
+};
+
+extern struct subcmd_config subcmd_config;
+
+#endif /* __PERF_SUBCMD_CONFIG_H */
diff --git a/tools/lib/subcmd/subcmd-util.h b/tools/lib/subcmd/subcmd-util.h
new file mode 100644
index 000000000..c742b0881
--- /dev/null
+++ b/tools/lib/subcmd/subcmd-util.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SUBCMD_UTIL_H
+#define __SUBCMD_UTIL_H
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <linux/compiler.h>
+
+static inline void report(const char *prefix, const char *err, va_list params)
+{
+	char msg[1024];
+	vsnprintf(msg, sizeof(msg), err, params);
+	fprintf(stderr, " %s%s\n", prefix, msg);
+}
+
+static __noreturn inline void die(const char *err, ...)
+{
+	va_list params;
+
+	va_start(params, err);
+	report(" Fatal: ", err, params);
+	va_end(params);
+	exit(128);
+}
+
+#define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
+
+#define alloc_nr(x) (((x)+16)*3/2)
+
+/*
+ * Realloc the buffer pointed at by variable 'x' so that it can hold
+ * at least 'nr' entries; the number of entries currently allocated
+ * is 'alloc', using the standard growing factor alloc_nr() macro.
+ *
+ * DO NOT USE any expression with side-effect for 'x' or 'alloc'.
+ */
+#define ALLOC_GROW(x, nr, alloc) \
+	do { \
+		if ((nr) > alloc) { \
+			if (alloc_nr(alloc) < (nr)) \
+				alloc = (nr); \
+			else \
+				alloc = alloc_nr(alloc); \
+			x = xrealloc((x), alloc * sizeof(*(x))); \
+		} \
+	} while(0)
+
+static inline void *xrealloc(void *ptr, size_t size)
+{
+	void *ret = realloc(ptr, size);
+	if (!ret)
+		die("Out of memory, realloc failed");
+	return ret;
+}
+
+#define astrcatf(out, fmt, ...)						\
+({									\
+	char *tmp = *(out);						\
+	if (asprintf((out), "%s" fmt, tmp ?: "", ## __VA_ARGS__) == -1)	\
+		die("asprintf failed");					\
+	free(tmp);							\
+})
+
+static inline void astrcat(char **out, const char *add)
+{
+	char *tmp = *out;
+
+	if (asprintf(out, "%s%s", tmp ?: "", add) == -1)
+		die("asprintf failed");
+
+	free(tmp);
+}
+
+#endif /* __SUBCMD_UTIL_H */
diff --git a/tools/lib/symbol/Build b/tools/lib/symbol/Build
new file mode 100644
index 000000000..9b9a9c78d
--- /dev/null
+++ b/tools/lib/symbol/Build
@@ -0,0 +1 @@
+libsymbol-y += kallsyms.o
diff --git a/tools/lib/symbol/Makefile b/tools/lib/symbol/Makefile
new file mode 100644
index 000000000..d692abe8a
--- /dev/null
+++ b/tools/lib/symbol/Makefile
@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../../scripts/Makefile.include
+include ../../scripts/utilities.mak		# QUIET_CLEAN
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+MAKEFLAGS += --no-print-directory
+
+INSTALL = install
+
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+LIBFILE = $(OUTPUT)libsymbol.a
+
+CFLAGS := $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
+CFLAGS += -ggdb3 -Wall -Wextra -std=gnu11 -U_FORTIFY_SOURCE -fPIC
+
+ifeq ($(DEBUG),0)
+  CFLAGS += -O3
+endif
+
+ifeq ($(DEBUG),0)
+  CFLAGS += -D_FORTIFY_SOURCE
+endif
+
+# Treat warnings as errors unless directed not to
+ifneq ($(WERROR),0)
+  CFLAGS += -Werror
+endif
+
+CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
+
+CFLAGS += -I$(srctree)/tools/lib
+CFLAGS += -I$(srctree)/tools/include
+
+RM = rm -f
+
+SYMBOL_IN := $(OUTPUT)libsymbol-in.o
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?=
+libdir = $(prefix)/$(libdir_relative)
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+include $(srctree)/tools/build/Makefile.include
+include $(srctree)/tools/scripts/Makefile.include
+
+all: fixdep $(LIBFILE)
+
+$(SYMBOL_IN): FORCE
+	@$(MAKE) $(build)=libsymbol
+
+$(LIBFILE): $(SYMBOL_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(SYMBOL_IN)
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
+	fi
+endef
+
+define do_install
+	if [ ! -d '$2' ]; then             \
+		$(INSTALL) -d -m 755 '$2'; \
+	fi;                                \
+	$(INSTALL) $1 $(if $3,-m $3,) '$2'
+endef
+
+install_lib: $(LIBFILE)
+	$(call QUIET_INSTALL, $(LIBFILE)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fpR $(LIBFILE) $(DESTDIR)$(libdir_SQ)
+
+HDRS := kallsyms.h
+INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/symbol
+INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))
+
+$(INSTALL_HDRS): $(INSTALL_HDRS_PFX)/%.h: %.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/,644)
+
+install_headers: $(INSTALL_HDRS)
+	$(call QUIET_INSTALL, libsymbol_headers)
+
+install: install_lib install_headers
+
+clean:
+	$(call QUIET_CLEAN, libsymbol) $(RM) $(LIBFILE); \
+	find $(or $(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+
+FORCE:
+
+.PHONY: clean FORCE
diff --git a/tools/lib/symbol/kallsyms.c b/tools/lib/symbol/kallsyms.c
new file mode 100644
index 000000000..d64bd9cc8
--- /dev/null
+++ b/tools/lib/symbol/kallsyms.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "symbol/kallsyms.h"
+#include "api/io.h"
+#include <stdio.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+u8 kallsyms2elf_type(char type)
+{
+	type = tolower(type);
+	return (type == 't' || type == 'w') ? STT_FUNC : STT_OBJECT;
+}
+
+bool kallsyms__is_function(char symbol_type)
+{
+	symbol_type = toupper(symbol_type);
+	return symbol_type == 'T' || symbol_type == 'W';
+}
+
+static void read_to_eol(struct io *io)
+{
+	int ch;
+
+	for (;;) {
+		ch = io__get_char(io);
+		if (ch < 0 || ch == '\n')
+			return;
+	}
+}
+
+int kallsyms__parse(const char *filename, void *arg,
+		    int (*process_symbol)(void *arg, const char *name,
+					  char type, u64 start))
+{
+	struct io io;
+	char bf[BUFSIZ];
+	int err;
+
+	io.fd = open(filename, O_RDONLY, 0);
+
+	if (io.fd < 0)
+		return -1;
+
+	io__init(&io, io.fd, bf, sizeof(bf));
+
+	err = 0;
+	while (!io.eof) {
+		__u64 start;
+		int ch;
+		size_t i;
+		char symbol_type;
+		char symbol_name[KSYM_NAME_LEN + 1];
+
+		if (io__get_hex(&io, &start) != ' ') {
+			read_to_eol(&io);
+			continue;
+		}
+		symbol_type = io__get_char(&io);
+		if (io__get_char(&io) != ' ') {
+			read_to_eol(&io);
+			continue;
+		}
+		for (i = 0; i < KSYM_NAME_LEN; i++) {
+			ch = io__get_char(&io);
+			if (ch < 0 || ch == '\n')
+				break;
+			symbol_name[i]  = ch;
+		}
+		symbol_name[i]  = '\0';
+
+		if (i == KSYM_NAME_LEN)
+			read_to_eol(&io);
+
+		err = process_symbol(arg, symbol_name, symbol_type, start);
+		if (err)
+			break;
+	}
+
+	close(io.fd);
+	return err;
+}
diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h
new file mode 100644
index 000000000..542f9b059
--- /dev/null
+++ b/tools/lib/symbol/kallsyms.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TOOLS_KALLSYMS_H_
+#define __TOOLS_KALLSYMS_H_ 1
+
+#include <elf.h>
+#include <linux/ctype.h>
+#include <linux/types.h>
+
+#ifndef KSYM_NAME_LEN
+#define KSYM_NAME_LEN 512
+#endif
+
+static inline u8 kallsyms2elf_binding(char type)
+{
+	if (type == 'W')
+		return STB_WEAK;
+
+	return isupper(type) ? STB_GLOBAL : STB_LOCAL;
+}
+
+u8 kallsyms2elf_type(char type);
+
+bool kallsyms__is_function(char symbol_type);
+
+int kallsyms__parse(const char *filename, void *arg,
+		    int (*process_symbol)(void *arg, const char *name,
+					  char type, u64 start));
+
+#endif /* __TOOLS_KALLSYMS_H_ */
diff --git a/tools/lib/thermal/.gitignore b/tools/lib/thermal/.gitignore
new file mode 100644
index 000000000..5d2aeda80
--- /dev/null
+++ b/tools/lib/thermal/.gitignore
@@ -0,0 +1,2 @@
+libthermal.so*
+libthermal.pc
diff --git a/tools/lib/thermal/Build b/tools/lib/thermal/Build
new file mode 100644
index 000000000..4a892d9e2
--- /dev/null
+++ b/tools/lib/thermal/Build
@@ -0,0 +1,5 @@
+libthermal-y += commands.o
+libthermal-y += events.o
+libthermal-y += thermal_nl.o
+libthermal-y += sampling.o
+libthermal-y += thermal.o
diff --git a/tools/lib/thermal/Makefile b/tools/lib/thermal/Makefile
new file mode 100644
index 000000000..41aa7a324
--- /dev/null
+++ b/tools/lib/thermal/Makefile
@@ -0,0 +1,159 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+# Most of this file is copied from tools/lib/perf/Makefile
+
+LIBTHERMAL_VERSION = 0
+LIBTHERMAL_PATCHLEVEL = 0
+LIBTHERMAL_EXTRAVERSION = 1
+
+MAKEFLAGS += --no-print-directory
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+# $(info Determined 'srctree' to be $(srctree))
+endif
+
+INSTALL = install
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+include $(srctree)/tools/scripts/Makefile.include
+include $(srctree)/tools/scripts/Makefile.arch
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?=
+libdir = $(prefix)/$(libdir_relative)
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
+
+# Set compile option CFLAGS
+ifdef EXTRA_CFLAGS
+  CFLAGS := $(EXTRA_CFLAGS)
+else
+  CFLAGS := -g -Wall
+endif
+
+NL3_CFLAGS = $(shell pkg-config --cflags libnl-3.0 2>/dev/null)
+ifeq ($(NL3_CFLAGS),)
+NL3_CFLAGS = -I/usr/include/libnl3
+endif
+
+INCLUDES = \
+-I$(srctree)/tools/lib/thermal/include \
+-I$(srctree)/tools/lib/ \
+-I$(srctree)/tools/include \
+-I$(srctree)/tools/arch/$(SRCARCH)/include/ \
+-I$(srctree)/tools/arch/$(SRCARCH)/include/uapi \
+-I$(srctree)/tools/include/uapi
+
+# Append required CFLAGS
+override CFLAGS += $(EXTRA_WARNINGS)
+override CFLAGS += -Werror -Wall
+override CFLAGS += -fPIC
+override CFLAGS += $(NL3_CFLAGS)
+override CFLAGS += $(INCLUDES)
+override CFLAGS += -fvisibility=hidden
+override CFGLAS += -Wl,-L.
+override CFGLAS += -Wl,-lthermal
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+export DESTDIR DESTDIR_SQ
+
+include $(srctree)/tools/build/Makefile.include
+
+VERSION_SCRIPT := libthermal.map
+
+PATCHLEVEL    = $(LIBTHERMAL_PATCHLEVEL)
+EXTRAVERSION  = $(LIBTHERMAL_EXTRAVERSION)
+VERSION       = $(LIBTHERMAL_VERSION).$(LIBTHERMAL_PATCHLEVEL).$(LIBTHERMAL_EXTRAVERSION)
+
+LIBTHERMAL_SO := $(OUTPUT)libthermal.so.$(VERSION)
+LIBTHERMAL_A  := $(OUTPUT)libthermal.a
+LIBTHERMAL_IN := $(OUTPUT)libthermal-in.o
+LIBTHERMAL_PC := $(OUTPUT)libthermal.pc
+LIBTHERMAL_ALL := $(LIBTHERMAL_A) $(OUTPUT)libthermal.so*
+
+THERMAL_UAPI := include/uapi/linux/thermal.h
+
+$(THERMAL_UAPI): FORCE
+	ln -sf $(srctree)/$@ $(srctree)/tools/$@
+
+$(LIBTHERMAL_IN): FORCE
+	$(Q)$(MAKE) $(build)=libthermal
+
+$(LIBTHERMAL_A): $(LIBTHERMAL_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIBTHERMAL_IN)
+
+$(LIBTHERMAL_SO): $(LIBTHERMAL_IN)
+	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libthermal.so \
+                                    -Wl,--version-script=$(VERSION_SCRIPT) $^ -o $@
+	@ln -sf $(@F) $(OUTPUT)libthermal.so
+	@ln -sf $(@F) $(OUTPUT)libthermal.so.$(LIBTHERMAL_VERSION)
+
+
+libs: $(THERMAL_UAPI) $(LIBTHERMAL_A) $(LIBTHERMAL_SO) $(LIBTHERMAL_PC)
+
+all: fixdep
+	$(Q)$(MAKE) libs
+
+clean:
+	$(call QUIET_CLEAN, libthermal) $(RM) $(LIBTHERMAL_A) \
+                *.o *~ *.a *.so *.so.$(VERSION) *.so.$(LIBTHERMAL_VERSION) \
+                .*.d .*.cmd LIBTHERMAL-CFLAGS $(LIBTHERMAL_PC) \
+                $(srctree)/tools/$(THERMAL_UAPI)
+
+$(LIBTHERMAL_PC):
+	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
+		-e "s|@LIBDIR@|$(libdir_SQ)|" \
+		-e "s|@VERSION@|$(VERSION)|" \
+		< libthermal.pc.template > $@
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
+	fi
+endef
+
+define do_install
+	if [ ! -d '$(DESTDIR_SQ)$2' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2'; \
+	fi;                                             \
+	$(INSTALL) $1 $(if $3,-m $3,) '$(DESTDIR_SQ)$2'
+endef
+
+install_lib: libs
+	$(call QUIET_INSTALL, $(LIBTHERMAL_ALL)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fR --preserve=mode,timestamp $(LIBTHERMAL_ALL) $(DESTDIR)$(libdir_SQ)
+
+install_headers:
+	$(call QUIET_INSTALL, headers) \
+		$(call do_install,include/thermal.h,$(prefix)/include/thermal,644); \
+
+install_pkgconfig: $(LIBTHERMAL_PC)
+	$(call QUIET_INSTALL, $(LIBTHERMAL_PC)) \
+		$(call do_install,$(LIBTHERMAL_PC),$(libdir_SQ)/pkgconfig,644)
+
+install_doc:
+	$(Q)$(MAKE) -C Documentation install-man install-html install-examples
+
+install: install_lib install_headers install_pkgconfig
+
+FORCE:
+
+.PHONY: all install clean FORCE
diff --git a/tools/lib/thermal/commands.c b/tools/lib/thermal/commands.c
new file mode 100644
index 000000000..4998cec79
--- /dev/null
+++ b/tools/lib/thermal/commands.c
@@ -0,0 +1,511 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include <thermal.h>
+#include "thermal_nl.h"
+
+static struct nla_policy thermal_genl_policy[THERMAL_GENL_ATTR_MAX + 1] = {
+	/* Thermal zone */
+	[THERMAL_GENL_ATTR_TZ]                  = { .type = NLA_NESTED },
+	[THERMAL_GENL_ATTR_TZ_ID]               = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_TEMP]             = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_TRIP]             = { .type = NLA_NESTED },
+	[THERMAL_GENL_ATTR_TZ_TRIP_ID]          = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_TRIP_TEMP]        = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_TRIP_TYPE]        = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_TRIP_HYST]        = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_MODE]             = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_CDEV_WEIGHT]      = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_TZ_NAME]             = { .type = NLA_STRING },
+
+	/* Governor(s) */
+	[THERMAL_GENL_ATTR_TZ_GOV]              = { .type = NLA_NESTED },
+	[THERMAL_GENL_ATTR_TZ_GOV_NAME]         = { .type = NLA_STRING },
+
+	/* Cooling devices */
+	[THERMAL_GENL_ATTR_CDEV]                = { .type = NLA_NESTED },
+	[THERMAL_GENL_ATTR_CDEV_ID]             = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_CDEV_CUR_STATE]      = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_CDEV_MAX_STATE]      = { .type = NLA_U32 },
+	[THERMAL_GENL_ATTR_CDEV_NAME]           = { .type = NLA_STRING },
+
+        /* Thresholds */
+        [THERMAL_GENL_ATTR_THRESHOLD]      	= { .type = NLA_NESTED },
+        [THERMAL_GENL_ATTR_THRESHOLD_TEMP]      = { .type = NLA_U32 },
+        [THERMAL_GENL_ATTR_THRESHOLD_DIRECTION] = { .type = NLA_U32 },
+};
+
+static int parse_tz_get(struct genl_info *info, struct thermal_zone **tz)
+{
+	struct nlattr *attr;
+	struct thermal_zone *__tz = NULL;
+	size_t size = 0;
+	int rem;
+
+	nla_for_each_nested(attr, info->attrs[THERMAL_GENL_ATTR_TZ], rem) {
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_TZ_ID) {
+
+			size++;
+
+			__tz = realloc(__tz, sizeof(*__tz) * (size + 2));
+			if (!__tz)
+				return THERMAL_ERROR;
+
+			__tz[size - 1].id = nla_get_u32(attr);
+		}
+
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_TZ_NAME)
+			nla_strlcpy(__tz[size - 1].name, attr,
+				    THERMAL_NAME_LENGTH);
+	}
+
+	if (__tz)
+		__tz[size].id = -1;
+
+	*tz = __tz;
+
+	return THERMAL_SUCCESS;
+}
+
+static int parse_cdev_get(struct genl_info *info, struct thermal_cdev **cdev)
+{
+	struct nlattr *attr;
+	struct thermal_cdev *__cdev = NULL;
+	size_t size = 0;
+	int rem;
+
+	nla_for_each_nested(attr, info->attrs[THERMAL_GENL_ATTR_CDEV], rem) {
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_CDEV_ID) {
+
+			size++;
+
+			__cdev = realloc(__cdev, sizeof(*__cdev) * (size + 2));
+			if (!__cdev)
+				return THERMAL_ERROR;
+
+			__cdev[size - 1].id = nla_get_u32(attr);
+		}
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_CDEV_NAME) {
+			nla_strlcpy(__cdev[size - 1].name, attr,
+				    THERMAL_NAME_LENGTH);
+		}
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_CDEV_CUR_STATE)
+			__cdev[size - 1].cur_state = nla_get_u32(attr);
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_CDEV_MAX_STATE)
+			__cdev[size - 1].max_state = nla_get_u32(attr);
+	}
+
+	if (__cdev)
+		__cdev[size].id = -1;
+
+	*cdev = __cdev;
+
+	return THERMAL_SUCCESS;
+}
+
+static int parse_tz_get_trip(struct genl_info *info, struct thermal_zone *tz)
+{
+	struct nlattr *attr;
+	struct thermal_trip *__tt = NULL;
+	size_t size = 0;
+	int rem;
+
+	nla_for_each_nested(attr, info->attrs[THERMAL_GENL_ATTR_TZ_TRIP], rem) {
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_TZ_TRIP_ID) {
+
+			size++;
+
+			__tt = realloc(__tt, sizeof(*__tt) * (size + 2));
+			if (!__tt)
+				return THERMAL_ERROR;
+
+			__tt[size - 1].id = nla_get_u32(attr);
+		}
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_TZ_TRIP_TYPE)
+			__tt[size - 1].type = nla_get_u32(attr);
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_TZ_TRIP_TEMP)
+			__tt[size - 1].temp = nla_get_u32(attr);
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_TZ_TRIP_HYST)
+			__tt[size - 1].hyst = nla_get_u32(attr);
+	}
+
+	if (__tt)
+		__tt[size].id = -1;
+
+	tz->trip = __tt;
+
+	return THERMAL_SUCCESS;
+}
+
+static int parse_tz_get_temp(struct genl_info *info, struct thermal_zone *tz)
+{
+	int id = -1;
+
+	if (info->attrs[THERMAL_GENL_ATTR_TZ_ID])
+		id = nla_get_u32(info->attrs[THERMAL_GENL_ATTR_TZ_ID]);
+
+	if (tz->id != id)
+		return THERMAL_ERROR;
+
+	if (info->attrs[THERMAL_GENL_ATTR_TZ_TEMP])
+		tz->temp = nla_get_u32(info->attrs[THERMAL_GENL_ATTR_TZ_TEMP]);
+
+	return THERMAL_SUCCESS;
+}
+
+static int parse_tz_get_gov(struct genl_info *info, struct thermal_zone *tz)
+{
+	int id = -1;
+
+	if (info->attrs[THERMAL_GENL_ATTR_TZ_ID])
+		id = nla_get_u32(info->attrs[THERMAL_GENL_ATTR_TZ_ID]);
+
+	if (tz->id != id)
+		return THERMAL_ERROR;
+
+	if (info->attrs[THERMAL_GENL_ATTR_TZ_GOV_NAME]) {
+		nla_strlcpy(tz->governor,
+			    info->attrs[THERMAL_GENL_ATTR_TZ_GOV_NAME],
+			    THERMAL_NAME_LENGTH);
+	}
+
+	return THERMAL_SUCCESS;
+}
+
+static int parse_threshold_get(struct genl_info *info, struct thermal_zone *tz)
+{
+	struct nlattr *attr;
+	struct thermal_threshold *__tt = NULL;
+	size_t size = 0;
+	int rem;
+
+	/*
+	 * The size contains the size of the array and we want to
+	 * access the last element, size - 1.
+	 *
+	 * The variable size is initialized to zero but it will be
+	 * then incremented by the first if() statement. The message
+	 * attributes are ordered, so the first if() statement will be
+	 * always called before the second one. If it happens that is
+	 * not the case, then it is a kernel bug.
+	 */
+	nla_for_each_nested(attr, info->attrs[THERMAL_GENL_ATTR_THRESHOLD], rem) {
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_THRESHOLD_TEMP) {
+
+			size++;
+
+			__tt = realloc(__tt, sizeof(*__tt) * (size + 2));
+			if (!__tt)
+				return THERMAL_ERROR;
+
+			__tt[size - 1].temperature = nla_get_u32(attr);
+		}
+
+		if (nla_type(attr) == THERMAL_GENL_ATTR_THRESHOLD_DIRECTION)
+			__tt[size - 1].direction = nla_get_u32(attr);
+	}
+
+	if (__tt)
+		__tt[size].temperature = INT_MAX;
+
+	tz->thresholds = __tt;
+
+	return THERMAL_SUCCESS;
+}
+
+static int handle_netlink(struct nl_cache_ops *unused,
+			  struct genl_cmd *cmd,
+			  struct genl_info *info, void *arg)
+{
+	int ret;
+
+	switch (cmd->c_id) {
+
+	case THERMAL_GENL_CMD_TZ_GET_ID:
+		ret = parse_tz_get(info, arg);
+		break;
+
+	case THERMAL_GENL_CMD_CDEV_GET:
+		ret = parse_cdev_get(info, arg);
+		break;
+
+	case THERMAL_GENL_CMD_TZ_GET_TEMP:
+		ret = parse_tz_get_temp(info, arg);
+		break;
+
+	case THERMAL_GENL_CMD_TZ_GET_TRIP:
+		ret = parse_tz_get_trip(info, arg);
+		break;
+
+	case THERMAL_GENL_CMD_TZ_GET_GOV:
+		ret = parse_tz_get_gov(info, arg);
+		break;
+
+	case THERMAL_GENL_CMD_THRESHOLD_GET:
+		ret = parse_threshold_get(info, arg);
+		break;
+
+	default:
+		return THERMAL_ERROR;
+	}
+
+	return ret;
+}
+
+static struct genl_cmd thermal_cmds[] = {
+	{
+		.c_id		= THERMAL_GENL_CMD_TZ_GET_ID,
+		.c_name		= (char *)"List thermal zones",
+		.c_msg_parser	= handle_netlink,
+		.c_maxattr	= THERMAL_GENL_ATTR_MAX,
+		.c_attr_policy	= thermal_genl_policy,
+	},
+	{
+		.c_id		= THERMAL_GENL_CMD_TZ_GET_GOV,
+		.c_name		= (char *)"Get governor",
+		.c_msg_parser	= handle_netlink,
+		.c_maxattr	= THERMAL_GENL_ATTR_MAX,
+		.c_attr_policy	= thermal_genl_policy,
+	},
+	{
+		.c_id		= THERMAL_GENL_CMD_TZ_GET_TEMP,
+		.c_name		= (char *)"Get thermal zone temperature",
+		.c_msg_parser	= handle_netlink,
+		.c_maxattr	= THERMAL_GENL_ATTR_MAX,
+		.c_attr_policy	= thermal_genl_policy,
+	},
+	{
+		.c_id		= THERMAL_GENL_CMD_TZ_GET_TRIP,
+		.c_name		= (char *)"Get thermal zone trip points",
+		.c_msg_parser	= handle_netlink,
+		.c_maxattr	= THERMAL_GENL_ATTR_MAX,
+		.c_attr_policy	= thermal_genl_policy,
+	},
+	{
+		.c_id		= THERMAL_GENL_CMD_CDEV_GET,
+		.c_name		= (char *)"Get cooling devices",
+		.c_msg_parser	= handle_netlink,
+		.c_maxattr	= THERMAL_GENL_ATTR_MAX,
+		.c_attr_policy	= thermal_genl_policy,
+	},
+        {
+                .c_id           = THERMAL_GENL_CMD_THRESHOLD_GET,
+                .c_name         = (char *)"Get thresholds list",
+                .c_msg_parser   = handle_netlink,
+                .c_maxattr      = THERMAL_GENL_ATTR_MAX,
+                .c_attr_policy  = thermal_genl_policy,
+        },
+        {
+                .c_id           = THERMAL_GENL_CMD_THRESHOLD_ADD,
+                .c_name         = (char *)"Add a threshold",
+                .c_msg_parser   = handle_netlink,
+                .c_maxattr      = THERMAL_GENL_ATTR_MAX,
+                .c_attr_policy  = thermal_genl_policy,
+        },
+        {
+                .c_id           = THERMAL_GENL_CMD_THRESHOLD_DELETE,
+                .c_name         = (char *)"Delete a threshold",
+                .c_msg_parser   = handle_netlink,
+                .c_maxattr      = THERMAL_GENL_ATTR_MAX,
+                .c_attr_policy  = thermal_genl_policy,
+        },
+        {
+                .c_id           = THERMAL_GENL_CMD_THRESHOLD_FLUSH,
+                .c_name         = (char *)"Flush the thresholds",
+                .c_msg_parser   = handle_netlink,
+                .c_maxattr      = THERMAL_GENL_ATTR_MAX,
+                .c_attr_policy  = thermal_genl_policy,
+        },
+};
+
+static struct genl_ops thermal_cmd_ops = {
+	.o_name		= (char *)"thermal",
+	.o_cmds		= thermal_cmds,
+	.o_ncmds	= ARRAY_SIZE(thermal_cmds),
+};
+
+struct cmd_param {
+	int tz_id;
+	int temp;
+	int direction;
+};
+
+typedef int (*cmd_cb_t)(struct nl_msg *, struct cmd_param *);
+
+static int thermal_genl_tz_id_encode(struct nl_msg *msg, struct cmd_param *p)
+{
+	if (nla_put_u32(msg, THERMAL_GENL_ATTR_TZ_ID, p->tz_id))
+		return -1;
+
+	return 0;
+}
+
+static int thermal_genl_threshold_encode(struct nl_msg *msg, struct cmd_param *p)
+{
+	if (thermal_genl_tz_id_encode(msg, p))
+		return -1;
+
+	if (nla_put_u32(msg, THERMAL_GENL_ATTR_THRESHOLD_TEMP, p->temp))
+		return -1;
+
+	if (nla_put_u32(msg, THERMAL_GENL_ATTR_THRESHOLD_DIRECTION, p->direction))
+		return -1;
+
+	return 0;
+}
+
+static thermal_error_t thermal_genl_auto(struct thermal_handler *th, cmd_cb_t cmd_cb,
+					 struct cmd_param *param,
+					 int cmd, int flags, void *arg)
+{
+	thermal_error_t ret = THERMAL_ERROR;
+	struct nl_msg *msg;
+	void *hdr;
+
+	msg = nlmsg_alloc();
+	if (!msg)
+		return THERMAL_ERROR;
+
+	hdr = genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, thermal_cmd_ops.o_id,
+			  0, flags, cmd, THERMAL_GENL_VERSION);
+	if (!hdr)
+		goto out;
+
+	if (cmd_cb && cmd_cb(msg, param))
+		goto out;
+
+	if (nl_send_msg(th->sk_cmd, th->cb_cmd, msg, genl_handle_msg, arg))
+		goto out;
+
+	ret = THERMAL_SUCCESS;
+out:
+	nlmsg_free(msg);
+
+	return ret;
+}
+
+thermal_error_t thermal_cmd_get_tz(struct thermal_handler *th, struct thermal_zone **tz)
+{
+	return thermal_genl_auto(th, NULL, NULL, THERMAL_GENL_CMD_TZ_GET_ID,
+				 NLM_F_DUMP | NLM_F_ACK, tz);
+}
+
+thermal_error_t thermal_cmd_get_cdev(struct thermal_handler *th, struct thermal_cdev **tc)
+{
+	return thermal_genl_auto(th, NULL, NULL, THERMAL_GENL_CMD_CDEV_GET,
+				 NLM_F_DUMP | NLM_F_ACK, tc);
+}
+
+thermal_error_t thermal_cmd_get_trip(struct thermal_handler *th, struct thermal_zone *tz)
+{
+	struct cmd_param p = { .tz_id = tz->id };
+
+	return thermal_genl_auto(th, thermal_genl_tz_id_encode, &p,
+				 THERMAL_GENL_CMD_TZ_GET_TRIP, 0, tz);
+}
+
+thermal_error_t thermal_cmd_get_governor(struct thermal_handler *th, struct thermal_zone *tz)
+{
+	struct cmd_param p = { .tz_id = tz->id };
+
+	return thermal_genl_auto(th, thermal_genl_tz_id_encode, &p,
+				 THERMAL_GENL_CMD_TZ_GET_GOV, 0, tz);
+}
+
+thermal_error_t thermal_cmd_get_temp(struct thermal_handler *th, struct thermal_zone *tz)
+{
+	struct cmd_param p = { .tz_id = tz->id };
+
+	return thermal_genl_auto(th, thermal_genl_tz_id_encode, &p,
+				 THERMAL_GENL_CMD_TZ_GET_TEMP, 0, tz);
+}
+
+thermal_error_t thermal_cmd_threshold_get(struct thermal_handler *th,
+                                          struct thermal_zone *tz)
+{
+	struct cmd_param p = { .tz_id = tz->id };
+
+        return thermal_genl_auto(th, thermal_genl_tz_id_encode, &p,
+				 THERMAL_GENL_CMD_THRESHOLD_GET, 0, tz);
+}
+
+thermal_error_t thermal_cmd_threshold_add(struct thermal_handler *th,
+                                          struct thermal_zone *tz,
+                                          int temperature,
+                                          int direction)
+{
+	struct cmd_param p = { .tz_id = tz->id, .temp = temperature, .direction = direction };
+
+        return thermal_genl_auto(th, thermal_genl_threshold_encode, &p,
+				 THERMAL_GENL_CMD_THRESHOLD_ADD, 0, tz);
+}
+
+thermal_error_t thermal_cmd_threshold_delete(struct thermal_handler *th,
+                                             struct thermal_zone *tz,
+                                             int temperature,
+                                             int direction)
+{
+	struct cmd_param p = { .tz_id = tz->id, .temp = temperature, .direction = direction };
+
+        return thermal_genl_auto(th, thermal_genl_threshold_encode, &p,
+				 THERMAL_GENL_CMD_THRESHOLD_DELETE, 0, tz);
+}
+
+thermal_error_t thermal_cmd_threshold_flush(struct thermal_handler *th,
+                                            struct thermal_zone *tz)
+{
+	struct cmd_param p = { .tz_id = tz->id };
+
+        return thermal_genl_auto(th, thermal_genl_tz_id_encode, &p,
+				 THERMAL_GENL_CMD_THRESHOLD_FLUSH, 0, tz);
+}
+
+thermal_error_t thermal_cmd_exit(struct thermal_handler *th)
+{
+	if (genl_unregister_family(&thermal_cmd_ops))
+		return THERMAL_ERROR;
+
+	nl_thermal_disconnect(th->sk_cmd, th->cb_cmd);
+
+	return THERMAL_SUCCESS;
+}
+
+thermal_error_t thermal_cmd_init(struct thermal_handler *th)
+{
+	int ret;
+	int family;
+
+	if (nl_thermal_connect(&th->sk_cmd, &th->cb_cmd))
+		return THERMAL_ERROR;
+
+	ret = genl_register_family(&thermal_cmd_ops);
+	if (ret)
+		return THERMAL_ERROR;
+
+	ret = genl_ops_resolve(th->sk_cmd, &thermal_cmd_ops);
+	if (ret)
+		return THERMAL_ERROR;
+
+	family = genl_ctrl_resolve(th->sk_cmd, "nlctrl");
+	if (family != GENL_ID_CTRL)
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}
diff --git a/tools/lib/thermal/events.c b/tools/lib/thermal/events.c
new file mode 100644
index 000000000..bd851c869
--- /dev/null
+++ b/tools/lib/thermal/events.c
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#include <linux/netlink.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+
+#include <thermal.h>
+#include "thermal_nl.h"
+
+/*
+ * Optimization: fill this array to tell which event we do want to pay
+ * attention to. That happens at init time with the ops
+ * structure. Each ops will enable the event and the general handler
+ * will be able to discard the event if there is not ops associated
+ * with it.
+ */
+static int enabled_ops[__THERMAL_GENL_EVENT_MAX];
+
+static int handle_thermal_event(struct nl_msg *n, void *arg)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(n);
+	struct genlmsghdr *genlhdr = genlmsg_hdr(nlh);
+	struct nlattr *attrs[THERMAL_GENL_ATTR_MAX + 1];
+	struct thermal_handler_param *thp = arg;
+	struct thermal_events_ops *ops = &thp->th->ops->events;
+
+	genlmsg_parse(nlh, 0, attrs, THERMAL_GENL_ATTR_MAX, NULL);
+
+	arg = thp->arg;
+
+	/*
+	 * This is an event we don't care of, bail out.
+	 */
+	if (!enabled_ops[genlhdr->cmd])
+		return THERMAL_SUCCESS;
+
+	switch (genlhdr->cmd) {
+
+	case THERMAL_GENL_EVENT_TZ_CREATE:
+		return ops->tz_create(nla_get_string(attrs[THERMAL_GENL_ATTR_TZ_NAME]),
+				      nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_DELETE:
+		return ops->tz_delete(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_ENABLE:
+		return ops->tz_enable(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_DISABLE:
+		return ops->tz_disable(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_TRIP_CHANGE:
+		return ops->trip_change(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+					nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_ID]),
+					nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_TYPE]),
+					nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_TEMP]),
+					nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_HYST]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_TRIP_ADD:
+		return ops->trip_add(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_ID]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_TYPE]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_TEMP]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_HYST]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_TRIP_DELETE:
+		return ops->trip_delete(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+					nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_ID]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_TRIP_UP:
+		return ops->trip_high(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+				      nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_ID]),
+				      nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TEMP]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_TRIP_DOWN:
+		return ops->trip_low(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TRIP_ID]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TEMP]), arg);
+
+	case THERMAL_GENL_EVENT_CDEV_ADD:
+		return ops->cdev_add(nla_get_string(attrs[THERMAL_GENL_ATTR_CDEV_NAME]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_CDEV_ID]),
+				     nla_get_u32(attrs[THERMAL_GENL_ATTR_CDEV_MAX_STATE]), arg);
+
+	case THERMAL_GENL_EVENT_CDEV_DELETE:
+		return ops->cdev_delete(nla_get_u32(attrs[THERMAL_GENL_ATTR_CDEV_ID]), arg);
+
+	case THERMAL_GENL_EVENT_CDEV_STATE_UPDATE:
+		return ops->cdev_update(nla_get_u32(attrs[THERMAL_GENL_ATTR_CDEV_ID]),
+					nla_get_u32(attrs[THERMAL_GENL_ATTR_CDEV_CUR_STATE]), arg);
+
+	case THERMAL_GENL_EVENT_TZ_GOV_CHANGE:
+		return ops->gov_change(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+				       nla_get_string(attrs[THERMAL_GENL_ATTR_GOV_NAME]), arg);
+
+	case THERMAL_GENL_EVENT_THRESHOLD_ADD:
+		return ops->threshold_add(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+					  nla_get_u32(attrs[THERMAL_GENL_ATTR_THRESHOLD_TEMP]),
+					  nla_get_u32(attrs[THERMAL_GENL_ATTR_THRESHOLD_DIRECTION]), arg);
+
+	case THERMAL_GENL_EVENT_THRESHOLD_DELETE:
+		return ops->threshold_delete(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+					     nla_get_u32(attrs[THERMAL_GENL_ATTR_THRESHOLD_TEMP]),
+					     nla_get_u32(attrs[THERMAL_GENL_ATTR_THRESHOLD_DIRECTION]), arg);
+
+	case THERMAL_GENL_EVENT_THRESHOLD_FLUSH:
+		return ops->threshold_flush(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]), arg);
+
+	case THERMAL_GENL_EVENT_THRESHOLD_UP:
+		return ops->threshold_up(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+					 nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TEMP]),
+					 nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_PREV_TEMP]), arg);
+
+	case THERMAL_GENL_EVENT_THRESHOLD_DOWN:
+		return ops->threshold_down(nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+					   nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TEMP]),
+					   nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_PREV_TEMP]), arg);
+
+	default:
+		return -1;
+	}
+}
+
+static void thermal_events_ops_init(struct thermal_events_ops *ops)
+{
+	enabled_ops[THERMAL_GENL_EVENT_TZ_CREATE]		= !!ops->tz_create;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_DELETE]		= !!ops->tz_delete;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_DISABLE]		= !!ops->tz_disable;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_ENABLE]		= !!ops->tz_enable;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_TRIP_UP]		= !!ops->trip_high;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_TRIP_DOWN]		= !!ops->trip_low;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_TRIP_CHANGE]		= !!ops->trip_change;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_TRIP_ADD]		= !!ops->trip_add;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_TRIP_DELETE]		= !!ops->trip_delete;
+	enabled_ops[THERMAL_GENL_EVENT_CDEV_ADD]		= !!ops->cdev_add;
+	enabled_ops[THERMAL_GENL_EVENT_CDEV_DELETE]		= !!ops->cdev_delete;
+	enabled_ops[THERMAL_GENL_EVENT_CDEV_STATE_UPDATE] 	= !!ops->cdev_update;
+	enabled_ops[THERMAL_GENL_EVENT_TZ_GOV_CHANGE]		= !!ops->gov_change;
+	enabled_ops[THERMAL_GENL_EVENT_THRESHOLD_ADD]		= !!ops->threshold_add;
+	enabled_ops[THERMAL_GENL_EVENT_THRESHOLD_DELETE]	= !!ops->threshold_delete;
+	enabled_ops[THERMAL_GENL_EVENT_THRESHOLD_FLUSH]		= !!ops->threshold_flush;
+	enabled_ops[THERMAL_GENL_EVENT_THRESHOLD_UP]		= !!ops->threshold_up;
+	enabled_ops[THERMAL_GENL_EVENT_THRESHOLD_DOWN]		= !!ops->threshold_down;
+}
+
+thermal_error_t thermal_events_handle(struct thermal_handler *th, void *arg)
+{
+	struct thermal_handler_param thp = { .th = th, .arg = arg };
+
+	if (!th)
+		return THERMAL_ERROR;
+
+	if (nl_cb_set(th->cb_event, NL_CB_VALID, NL_CB_CUSTOM,
+		      handle_thermal_event, &thp))
+		return THERMAL_ERROR;
+
+	return nl_recvmsgs(th->sk_event, th->cb_event);
+}
+
+int thermal_events_fd(struct thermal_handler *th)
+{
+	if (!th)
+		return -1;
+
+	return nl_socket_get_fd(th->sk_event);
+}
+
+thermal_error_t thermal_events_exit(struct thermal_handler *th)
+{
+	if (nl_unsubscribe_thermal(th->sk_event, th->cb_event,
+				   THERMAL_GENL_EVENT_GROUP_NAME))
+		return THERMAL_ERROR;
+
+	nl_thermal_disconnect(th->sk_event, th->cb_event);
+
+	return THERMAL_SUCCESS;
+}
+
+thermal_error_t thermal_events_init(struct thermal_handler *th)
+{
+	thermal_events_ops_init(&th->ops->events);
+
+	if (nl_thermal_connect(&th->sk_event, &th->cb_event))
+		return THERMAL_ERROR;
+
+	if (nl_subscribe_thermal(th->sk_event, th->cb_event,
+				 THERMAL_GENL_EVENT_GROUP_NAME))
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}
diff --git a/tools/lib/thermal/include/thermal.h b/tools/lib/thermal/include/thermal.h
new file mode 100644
index 000000000..d9097271d
--- /dev/null
+++ b/tools/lib/thermal/include/thermal.h
@@ -0,0 +1,182 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/* Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org> */
+#ifndef __LIBTHERMAL_H
+#define __LIBTHERMAL_H
+
+#include <linux/thermal.h>
+#include <sys/types.h>
+
+#ifndef LIBTHERMAL_API
+#define LIBTHERMAL_API __attribute__((visibility("default")))
+#endif
+
+#ifndef THERMAL_THRESHOLD_WAY_UP
+#define THERMAL_THRESHOLD_WAY_UP 0x1
+#endif
+
+#ifndef THERMAL_THRESHOLD_WAY_DOWN
+#define THERMAL_THRESHOLD_WAY_DOWN 0x2
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct thermal_sampling_ops {
+	int (*tz_temp)(int tz_id, int temp, void *arg);
+};
+
+struct thermal_events_ops {
+	int (*tz_create)(const char *name, int tz_id, void *arg);
+	int (*tz_delete)(int tz_id, void *arg);
+	int (*tz_enable)(int tz_id, void *arg);
+	int (*tz_disable)(int tz_id, void *arg);
+	int (*trip_high)(int tz_id, int trip_id, int temp, void *arg);
+	int (*trip_low)(int tz_id, int trip_id, int temp, void *arg);
+	int (*trip_add)(int tz_id, int trip_id, int type, int temp, int hyst, void *arg);
+	int (*trip_change)(int tz_id, int trip_id, int type, int temp, int hyst, void *arg);
+	int (*trip_delete)(int tz_id, int trip_id, void *arg);
+	int (*cdev_add)(const char *name, int cdev_id, int max_state, void *arg);
+	int (*cdev_delete)(int cdev_id, void *arg);
+	int (*cdev_update)(int cdev_id, int cur_state, void *arg);
+	int (*gov_change)(int tz_id, const char *gov_name, void *arg);
+	int (*threshold_add)(int tz_id, int temperature, int direction, void *arg);
+	int (*threshold_delete)(int tz_id, int temperature, int direction, void *arg);
+	int (*threshold_flush)(int tz_id, void *arg);
+	int (*threshold_up)(int tz_id, int temp, int prev_temp, void *arg);
+	int (*threshold_down)(int tz_id, int temp, int prev_temp, void *arg);
+};
+
+struct thermal_ops {
+	struct thermal_sampling_ops sampling;
+	struct thermal_events_ops events;
+};
+
+struct thermal_trip {
+	int id;
+	int type;
+	int temp;
+	int hyst;
+};
+
+struct thermal_threshold {
+	int temperature;
+	int direction;
+};
+
+struct thermal_zone {
+	int id;
+	int temp;
+	char name[THERMAL_NAME_LENGTH];
+	char governor[THERMAL_NAME_LENGTH];
+	struct thermal_trip *trip;
+	struct thermal_threshold *thresholds;
+};
+
+struct thermal_cdev {
+	int id;
+	char name[THERMAL_NAME_LENGTH];
+	int max_state;
+	int min_state;
+	int cur_state;
+};
+
+typedef enum {
+	THERMAL_ERROR = -1,
+	THERMAL_SUCCESS = 0,
+} thermal_error_t;
+
+struct thermal_handler;
+
+typedef int (*cb_tz_t)(struct thermal_zone *, void *);
+
+typedef int (*cb_tt_t)(struct thermal_trip *, void *);
+
+typedef int (*cb_tc_t)(struct thermal_cdev *, void *);
+
+typedef int (*cb_th_t)(struct thermal_threshold *, void *);
+
+LIBTHERMAL_API int for_each_thermal_zone(struct thermal_zone *tz, cb_tz_t cb, void *arg);
+
+LIBTHERMAL_API int for_each_thermal_trip(struct thermal_trip *tt, cb_tt_t cb, void *arg);
+
+LIBTHERMAL_API int for_each_thermal_cdev(struct thermal_cdev *cdev, cb_tc_t cb, void *arg);
+
+LIBTHERMAL_API int for_each_thermal_threshold(struct thermal_threshold *th, cb_th_t cb, void *arg);
+
+LIBTHERMAL_API struct thermal_zone *thermal_zone_find_by_name(struct thermal_zone *tz,
+							      const char *name);
+
+LIBTHERMAL_API struct thermal_zone *thermal_zone_find_by_id(struct thermal_zone *tz, int id);
+
+LIBTHERMAL_API struct thermal_zone *thermal_zone_discover(struct thermal_handler *th);
+
+LIBTHERMAL_API struct thermal_handler *thermal_init(struct thermal_ops *ops);
+
+LIBTHERMAL_API void thermal_exit(struct thermal_handler *th);
+
+/*
+ * Netlink thermal events
+ */
+LIBTHERMAL_API thermal_error_t thermal_events_exit(struct thermal_handler *th);
+
+LIBTHERMAL_API thermal_error_t thermal_events_init(struct thermal_handler *th);
+
+LIBTHERMAL_API thermal_error_t thermal_events_handle(struct thermal_handler *th, void *arg);
+
+LIBTHERMAL_API int thermal_events_fd(struct thermal_handler *th);
+
+/*
+ * Netlink thermal commands
+ */
+LIBTHERMAL_API thermal_error_t thermal_cmd_exit(struct thermal_handler *th);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_init(struct thermal_handler *th);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_get_tz(struct thermal_handler *th,
+						  struct thermal_zone **tz);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_get_cdev(struct thermal_handler *th,
+						    struct thermal_cdev **tc);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_get_trip(struct thermal_handler *th,
+						    struct thermal_zone *tz);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_get_governor(struct thermal_handler *th,
+							struct thermal_zone *tz);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_get_temp(struct thermal_handler *th,
+						    struct thermal_zone *tz);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_threshold_get(struct thermal_handler *th,
+							 struct thermal_zone *tz);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_threshold_add(struct thermal_handler *th,
+                                                         struct thermal_zone *tz,
+                                                         int temperature,
+                                                         int direction);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_threshold_delete(struct thermal_handler *th,
+                                                            struct thermal_zone *tz,
+                                                            int temperature,
+                                                            int direction);
+
+LIBTHERMAL_API thermal_error_t thermal_cmd_threshold_flush(struct thermal_handler *th,
+                                                           struct thermal_zone *tz);
+
+/*
+ * Netlink thermal samples
+ */
+LIBTHERMAL_API thermal_error_t thermal_sampling_exit(struct thermal_handler *th);
+
+LIBTHERMAL_API thermal_error_t thermal_sampling_init(struct thermal_handler *th);
+
+LIBTHERMAL_API thermal_error_t thermal_sampling_handle(struct thermal_handler *th, void *arg);
+
+LIBTHERMAL_API int thermal_sampling_fd(struct thermal_handler *th);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LIBTHERMAL_H */
diff --git a/tools/lib/thermal/libthermal.map b/tools/lib/thermal/libthermal.map
new file mode 100644
index 000000000..1d3d0c04e
--- /dev/null
+++ b/tools/lib/thermal/libthermal.map
@@ -0,0 +1,33 @@
+LIBTHERMAL_0.0.1 {
+	global:
+		for_each_thermal_zone;
+		for_each_thermal_trip;
+		for_each_thermal_cdev;
+		for_each_thermal_threshold;
+		thermal_zone_find_by_name;
+		thermal_zone_find_by_id;
+		thermal_zone_discover;
+		thermal_init;
+		thermal_exit;
+		thermal_events_exit;
+		thermal_events_init;
+		thermal_events_handle;
+		thermal_events_fd;
+		thermal_cmd_exit;
+		thermal_cmd_init;
+		thermal_cmd_get_tz;
+		thermal_cmd_get_cdev;
+		thermal_cmd_get_trip;
+		thermal_cmd_get_governor;
+		thermal_cmd_get_temp;
+		thermal_cmd_threshold_get;
+		thermal_cmd_threshold_add;
+		thermal_cmd_threshold_delete;
+		thermal_cmd_threshold_flush;
+		thermal_sampling_exit;
+		thermal_sampling_init;
+		thermal_sampling_handle;
+		thermal_sampling_fd;
+local:
+		*;
+};
diff --git a/tools/lib/thermal/libthermal.pc.template b/tools/lib/thermal/libthermal.pc.template
new file mode 100644
index 000000000..3b8a24d0a
--- /dev/null
+++ b/tools/lib/thermal/libthermal.pc.template
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+prefix=@PREFIX@
+libdir=@LIBDIR@
+includedir=${prefix}/include
+
+Name: libthermal
+Description: thermal library
+Requires: libnl-3.0 libnl-genl-3.0
+Version: @VERSION@
+Libs: -L${libdir} -lnl-genl-3 -lnl-3 -lthermal
+Cflags: -I${includedir} -I${includedir}/libnl3
diff --git a/tools/lib/thermal/sampling.c b/tools/lib/thermal/sampling.c
new file mode 100644
index 000000000..f67c1f9ea
--- /dev/null
+++ b/tools/lib/thermal/sampling.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <thermal.h>
+#include "thermal_nl.h"
+
+static int handle_thermal_sample(struct nl_msg *n, void *arg)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(n);
+	struct genlmsghdr *genlhdr = genlmsg_hdr(nlh);
+	struct nlattr *attrs[THERMAL_GENL_ATTR_MAX + 1];
+	struct thermal_handler_param *thp = arg;
+	struct thermal_handler *th = thp->th;
+
+	arg = thp->arg;
+
+	genlmsg_parse(nlh, 0, attrs, THERMAL_GENL_ATTR_MAX, NULL);
+
+	switch (genlhdr->cmd) {
+
+	case THERMAL_GENL_SAMPLING_TEMP:
+		return th->ops->sampling.tz_temp(
+			nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_ID]),
+			nla_get_u32(attrs[THERMAL_GENL_ATTR_TZ_TEMP]), arg);
+	default:
+		return THERMAL_ERROR;
+	}
+}
+
+thermal_error_t thermal_sampling_handle(struct thermal_handler *th, void *arg)
+{
+	struct thermal_handler_param thp = { .th = th, .arg = arg };
+
+	if (!th)
+		return THERMAL_ERROR;
+
+	if (nl_cb_set(th->cb_sampling, NL_CB_VALID, NL_CB_CUSTOM,
+		      handle_thermal_sample, &thp))
+		return THERMAL_ERROR;
+
+	return nl_recvmsgs(th->sk_sampling, th->cb_sampling);
+}
+
+int thermal_sampling_fd(struct thermal_handler *th)
+{
+	if (!th)
+		return -1;
+
+	return nl_socket_get_fd(th->sk_sampling);
+}
+
+thermal_error_t thermal_sampling_exit(struct thermal_handler *th)
+{
+	if (nl_unsubscribe_thermal(th->sk_sampling, th->cb_sampling,
+				   THERMAL_GENL_SAMPLING_GROUP_NAME))
+		return THERMAL_ERROR;
+
+	nl_thermal_disconnect(th->sk_sampling, th->cb_sampling);
+
+	return THERMAL_SUCCESS;
+}
+
+thermal_error_t thermal_sampling_init(struct thermal_handler *th)
+{
+	if (nl_thermal_connect(&th->sk_sampling, &th->cb_sampling))
+		return THERMAL_ERROR;
+
+	if (nl_subscribe_thermal(th->sk_sampling, th->cb_sampling,
+				 THERMAL_GENL_SAMPLING_GROUP_NAME))
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}
diff --git a/tools/lib/thermal/thermal.c b/tools/lib/thermal/thermal.c
new file mode 100644
index 000000000..6f02e3539
--- /dev/null
+++ b/tools/lib/thermal/thermal.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#include <stdio.h>
+#include <limits.h>
+#include <thermal.h>
+
+#include "thermal_nl.h"
+
+int for_each_thermal_threshold(struct thermal_threshold *th, cb_th_t cb, void *arg)
+{
+	int i, ret = 0;
+
+	if (!th)
+		return 0;
+
+	for (i = 0; th[i].temperature != INT_MAX; i++)
+		ret |= cb(&th[i], arg);
+
+	return ret;
+}
+
+int for_each_thermal_cdev(struct thermal_cdev *cdev, cb_tc_t cb, void *arg)
+{
+	int i, ret = 0;
+
+	if (!cdev)
+		return 0;
+
+	for (i = 0; cdev[i].id != -1; i++)
+		ret |= cb(&cdev[i], arg);
+
+	return ret;
+}
+
+int for_each_thermal_trip(struct thermal_trip *tt, cb_tt_t cb, void *arg)
+{
+	int i, ret = 0;
+
+	if (!tt)
+		return 0;
+
+	for (i = 0; tt[i].id != -1; i++)
+		ret |= cb(&tt[i], arg);
+
+	return ret;
+}
+
+int for_each_thermal_zone(struct thermal_zone *tz, cb_tz_t cb, void *arg)
+{
+	int i, ret = 0;
+
+	if (!tz)
+		return 0;
+
+	for (i = 0; tz[i].id != -1; i++)
+		ret |= cb(&tz[i], arg);
+
+	return ret;
+}
+
+struct thermal_zone *thermal_zone_find_by_name(struct thermal_zone *tz,
+					       const char *name)
+{
+	int i;
+
+	if (!tz || !name)
+		return NULL;
+
+	for (i = 0; tz[i].id != -1; i++) {
+		if (!strcmp(tz[i].name, name))
+			return &tz[i];
+	}
+
+	return NULL;
+}
+
+struct thermal_zone *thermal_zone_find_by_id(struct thermal_zone *tz, int id)
+{
+	int i;
+
+	if (!tz || id < 0)
+		return NULL;
+
+	for (i = 0; tz[i].id != -1; i++) {
+		if (tz[i].id == id)
+			return &tz[i];
+	}
+
+	return NULL;
+}
+
+static int __thermal_zone_discover(struct thermal_zone *tz, void *th)
+{
+	if (thermal_cmd_get_trip(th, tz) < 0)
+		return -1;
+
+	if (thermal_cmd_threshold_get(th, tz))
+		return -1;
+
+	if (thermal_cmd_get_governor(th, tz))
+		return -1;
+
+	return 0;
+}
+
+struct thermal_zone *thermal_zone_discover(struct thermal_handler *th)
+{
+	struct thermal_zone *tz;
+
+	if (thermal_cmd_get_tz(th, &tz) < 0)
+		return NULL;
+
+	if (for_each_thermal_zone(tz, __thermal_zone_discover, th))
+		return NULL;
+
+	return tz;
+}
+
+void thermal_exit(struct thermal_handler *th)
+{
+	thermal_cmd_exit(th);
+	thermal_events_exit(th);
+	thermal_sampling_exit(th);
+
+	free(th);
+}
+
+struct thermal_handler *thermal_init(struct thermal_ops *ops)
+{
+	struct thermal_handler *th;
+
+	th = malloc(sizeof(*th));
+	if (!th)
+		return NULL;
+	th->ops = ops;
+
+	if (thermal_events_init(th))
+		goto out_free;
+
+	if (thermal_sampling_init(th))
+		goto out_free;
+
+	if (thermal_cmd_init(th))
+		goto out_free;
+
+	return th;
+
+out_free:
+	free(th);
+
+	return NULL;
+}
diff --git a/tools/lib/thermal/thermal_nl.c b/tools/lib/thermal/thermal_nl.c
new file mode 100644
index 000000000..b05cf9569
--- /dev/null
+++ b/tools/lib/thermal/thermal_nl.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <thermal.h>
+#include "thermal_nl.h"
+
+struct handler_args {
+	const char *group;
+	int id;
+};
+
+static __thread int err;
+static __thread int done;
+
+static int nl_seq_check_handler(struct nl_msg *msg, void *arg)
+{
+	return NL_OK;
+}
+
+static int nl_error_handler(struct sockaddr_nl *nla, struct nlmsgerr *nl_err,
+			    void *arg)
+{
+	int *ret = arg;
+
+	if (ret)
+		*ret = nl_err->error;
+
+	return NL_STOP;
+}
+
+static int nl_finish_handler(struct nl_msg *msg, void *arg)
+{
+	int *ret = arg;
+
+	if (ret)
+		*ret = 1;
+
+	return NL_OK;
+}
+
+static int nl_ack_handler(struct nl_msg *msg, void *arg)
+{
+	int *ret = arg;
+
+	if (ret)
+		*ret = 1;
+
+	return NL_OK;
+}
+
+int nl_send_msg(struct nl_sock *sock, struct nl_cb *cb, struct nl_msg *msg,
+		int (*rx_handler)(struct nl_msg *, void *), void *data)
+{
+	if (!rx_handler)
+		return THERMAL_ERROR;
+
+	err = nl_send_auto_complete(sock, msg);
+	if (err < 0)
+		return err;
+
+	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, rx_handler, data);
+
+	err = done = 0;
+
+	while (err == 0 && done == 0)
+		nl_recvmsgs(sock, cb);
+
+	return err;
+}
+
+static int nl_family_handler(struct nl_msg *msg, void *arg)
+{
+	struct handler_args *grp = arg;
+	struct nlattr *tb[CTRL_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	struct nlattr *mcgrp;
+	int rem_mcgrp;
+
+	nla_parse(tb, CTRL_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+		  genlmsg_attrlen(gnlh, 0), NULL);
+
+	if (!tb[CTRL_ATTR_MCAST_GROUPS])
+		return THERMAL_ERROR;
+
+	nla_for_each_nested(mcgrp, tb[CTRL_ATTR_MCAST_GROUPS], rem_mcgrp) {
+
+		struct nlattr *tb_mcgrp[CTRL_ATTR_MCAST_GRP_MAX + 1];
+
+		nla_parse(tb_mcgrp, CTRL_ATTR_MCAST_GRP_MAX,
+			  nla_data(mcgrp), nla_len(mcgrp), NULL);
+
+		if (!tb_mcgrp[CTRL_ATTR_MCAST_GRP_NAME] ||
+		    !tb_mcgrp[CTRL_ATTR_MCAST_GRP_ID])
+			continue;
+
+		if (strncmp(nla_data(tb_mcgrp[CTRL_ATTR_MCAST_GRP_NAME]),
+			    grp->group,
+			    nla_len(tb_mcgrp[CTRL_ATTR_MCAST_GRP_NAME])))
+			continue;
+
+		grp->id = nla_get_u32(tb_mcgrp[CTRL_ATTR_MCAST_GRP_ID]);
+
+		break;
+	}
+
+	return THERMAL_SUCCESS;
+}
+
+static int nl_get_multicast_id(struct nl_sock *sock, struct nl_cb *cb,
+			       const char *family, const char *group)
+{
+	struct nl_msg *msg;
+	int ret = 0, ctrlid;
+	struct handler_args grp = {
+		.group = group,
+		.id = -ENOENT,
+	};
+
+	msg = nlmsg_alloc();
+	if (!msg)
+		return THERMAL_ERROR;
+
+	ctrlid = genl_ctrl_resolve(sock, "nlctrl");
+
+	genlmsg_put(msg, 0, 0, ctrlid, 0, 0, CTRL_CMD_GETFAMILY, 0);
+
+	nla_put_string(msg, CTRL_ATTR_FAMILY_NAME, family);
+
+	ret = nl_send_msg(sock, cb, msg, nl_family_handler, &grp);
+	if (ret)
+		goto nla_put_failure;
+
+	ret = grp.id;
+
+nla_put_failure:
+	nlmsg_free(msg);
+	return ret;
+}
+
+int nl_thermal_connect(struct nl_sock **nl_sock, struct nl_cb **nl_cb)
+{
+	struct nl_cb *cb;
+	struct nl_sock *sock;
+
+	cb = nl_cb_alloc(NL_CB_DEFAULT);
+	if (!cb)
+		return THERMAL_ERROR;
+
+	sock = nl_socket_alloc();
+	if (!sock)
+		goto out_cb_free;
+
+	if (genl_connect(sock))
+		goto out_socket_free;
+
+	if (nl_cb_err(cb, NL_CB_CUSTOM, nl_error_handler, &err) ||
+	    nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, nl_finish_handler, &done) ||
+	    nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, nl_ack_handler, &done) ||
+	    nl_cb_set(cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, nl_seq_check_handler, &done))
+		return THERMAL_ERROR;
+
+	*nl_sock = sock;
+	*nl_cb = cb;
+
+	return THERMAL_SUCCESS;
+
+out_socket_free:
+	nl_socket_free(sock);
+out_cb_free:
+	nl_cb_put(cb);
+	return THERMAL_ERROR;
+}
+
+void nl_thermal_disconnect(struct nl_sock *nl_sock, struct nl_cb *nl_cb)
+{
+	nl_close(nl_sock);
+	nl_socket_free(nl_sock);
+	nl_cb_put(nl_cb);
+}
+
+int nl_unsubscribe_thermal(struct nl_sock *nl_sock, struct nl_cb *nl_cb,
+			   const char *group)
+{
+	int mcid;
+
+	mcid = nl_get_multicast_id(nl_sock, nl_cb, THERMAL_GENL_FAMILY_NAME,
+				   group);
+	if (mcid < 0)
+		return THERMAL_ERROR;
+
+	if (nl_socket_drop_membership(nl_sock, mcid))
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}
+
+int nl_subscribe_thermal(struct nl_sock *nl_sock, struct nl_cb *nl_cb,
+			 const char *group)
+{
+	int mcid;
+
+	mcid = nl_get_multicast_id(nl_sock, nl_cb, THERMAL_GENL_FAMILY_NAME,
+				   group);
+	if (mcid < 0)
+		return THERMAL_ERROR;
+
+	if (nl_socket_add_membership(nl_sock, mcid))
+		return THERMAL_ERROR;
+
+	return THERMAL_SUCCESS;
+}
diff --git a/tools/lib/thermal/thermal_nl.h b/tools/lib/thermal/thermal_nl.h
new file mode 100644
index 000000000..ddf635642
--- /dev/null
+++ b/tools/lib/thermal/thermal_nl.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/* Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org> */
+#ifndef __THERMAL_H
+#define __THERMAL_H
+
+#include <netlink/netlink.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/mngt.h>
+#include <netlink/genl/ctrl.h>
+
+struct thermal_handler {
+	int done;
+	int error;
+	struct thermal_ops *ops;
+	struct nl_msg *msg;
+	struct nl_sock *sk_event;
+	struct nl_sock *sk_sampling;
+	struct nl_sock *sk_cmd;
+	struct nl_cb *cb_cmd;
+	struct nl_cb *cb_event;
+	struct nl_cb *cb_sampling;
+};
+
+struct thermal_handler_param {
+	struct thermal_handler *th;
+	void *arg;
+};
+
+/*
+ * Low level netlink
+ */
+extern int nl_subscribe_thermal(struct nl_sock *nl_sock, struct nl_cb *nl_cb,
+				const char *group);
+
+extern int nl_unsubscribe_thermal(struct nl_sock *nl_sock, struct nl_cb *nl_cb,
+				  const char *group);
+
+extern int nl_thermal_connect(struct nl_sock **nl_sock, struct nl_cb **nl_cb);
+
+extern void nl_thermal_disconnect(struct nl_sock *nl_sock, struct nl_cb *nl_cb);
+
+extern int nl_send_msg(struct nl_sock *sock, struct nl_cb *nl_cb, struct nl_msg *msg,
+		       int (*rx_handler)(struct nl_msg *, void *),
+		       void *data);
+
+#endif /* __THERMAL_H */
diff --git a/tools/lib/vsprintf.c b/tools/lib/vsprintf.c
new file mode 100644
index 000000000..8780b4cda
--- /dev/null
+++ b/tools/lib/vsprintf.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <sys/types.h>
+#include <linux/kernel.h>
+#include <stdio.h>
+
+int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
+{
+       int i = vsnprintf(buf, size, fmt, args);
+       ssize_t ssize = size;
+
+       return (i >= ssize) ? (ssize - 1) : i;
+}
+
+int scnprintf(char * buf, size_t size, const char * fmt, ...)
+{
+       ssize_t ssize = size;
+       va_list args;
+       int i;
+
+       va_start(args, fmt);
+       i = vsnprintf(buf, size, fmt, args);
+       va_end(args);
+
+       return (i >= ssize) ? (ssize - 1) : i;
+}
+
+int scnprintf_pad(char * buf, size_t size, const char * fmt, ...)
+{
+	ssize_t ssize = size;
+	va_list args;
+	int i;
+
+	va_start(args, fmt);
+	i = vscnprintf(buf, size, fmt, args);
+	va_end(args);
+
+	if (i < (int) size) {
+		for (; i < (int) size; i++)
+			buf[i] = ' ';
+		buf[i] = 0x0;
+	}
+
+	return (i >= ssize) ? (ssize - 1) : i;
+}
diff --git a/tools/lib/zalloc.c b/tools/lib/zalloc.c
new file mode 100644
index 000000000..9c856d59f
--- /dev/null
+++ b/tools/lib/zalloc.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+#include <stdlib.h>
+#include <linux/zalloc.h>
+
+void *zalloc(size_t size)
+{
+	return calloc(1, size);
+}
+
+void __zfree(void **ptr)
+{
+	free(*ptr);
+	*ptr = NULL;
+}