Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 2077 insertions, 0 deletions

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
new file mode 100644
index 000000000..42bfe30a3
--- /dev/null
+++ b/tools/perf/util/dso.c
@@ -0,0 +1,2077 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/bug.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/zalloc.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#ifdef HAVE_LIBBPF_SUPPORT
+#include <bpf/libbpf.h>
+#include "bpf-event.h"
+#include "bpf-utils.h"
+#endif
+#include "compress.h"
+#include "env.h"
+#include "namespaces.h"
+#include "path.h"
+#include "map.h"
+#include "symbol.h"
+#include "srcline.h"
+#include "dso.h"
+#include "dsos.h"
+#include "machine.h"
+#include "auxtrace.h"
+#include "util.h" /* O_CLOEXEC for older systems */
+#include "debug.h"
+#include "string2.h"
+#include "vdso.h"
+#include "annotate-data.h"
+#include "libdw.h"
+
+static const char * const debuglink_paths[] = {
+	"%.0s%s",
+	"%s/%s",
+	"%s/.debug/%s",
+	"/usr/lib/debug%s/%s"
+};
+
+void dso__set_nsinfo(struct dso *dso, struct nsinfo *nsi)
+{
+	nsinfo__put(RC_CHK_ACCESS(dso)->nsinfo);
+	RC_CHK_ACCESS(dso)->nsinfo = nsi;
+}
+
+char dso__symtab_origin(const struct dso *dso)
+{
+	static const char origin[] = {
+		[DSO_BINARY_TYPE__KALLSYMS]			= 'k',
+		[DSO_BINARY_TYPE__VMLINUX]			= 'v',
+		[DSO_BINARY_TYPE__JAVA_JIT]			= 'j',
+		[DSO_BINARY_TYPE__DEBUGLINK]			= 'l',
+		[DSO_BINARY_TYPE__BUILD_ID_CACHE]		= 'B',
+		[DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO]	= 'D',
+		[DSO_BINARY_TYPE__FEDORA_DEBUGINFO]		= 'f',
+		[DSO_BINARY_TYPE__UBUNTU_DEBUGINFO]		= 'u',
+		[DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO]	= 'x',
+		[DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO]	= 'o',
+		[DSO_BINARY_TYPE__BUILDID_DEBUGINFO]		= 'b',
+		[DSO_BINARY_TYPE__SYSTEM_PATH_DSO]		= 'd',
+		[DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE]		= 'K',
+		[DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP]	= 'm',
+		[DSO_BINARY_TYPE__GUEST_KALLSYMS]		= 'g',
+		[DSO_BINARY_TYPE__GUEST_KMODULE]		= 'G',
+		[DSO_BINARY_TYPE__GUEST_KMODULE_COMP]		= 'M',
+		[DSO_BINARY_TYPE__GUEST_VMLINUX]		= 'V',
+		[DSO_BINARY_TYPE__GNU_DEBUGDATA]		= 'n',
+	};
+
+	if (dso == NULL || dso__symtab_type(dso) == DSO_BINARY_TYPE__NOT_FOUND)
+		return '!';
+	return origin[dso__symtab_type(dso)];
+}
+
+bool dso__is_object_file(const struct dso *dso)
+{
+	switch (dso__binary_type(dso)) {
+	case DSO_BINARY_TYPE__KALLSYMS:
+	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
+	case DSO_BINARY_TYPE__JAVA_JIT:
+	case DSO_BINARY_TYPE__BPF_PROG_INFO:
+	case DSO_BINARY_TYPE__BPF_IMAGE:
+	case DSO_BINARY_TYPE__OOL:
+		return false;
+	case DSO_BINARY_TYPE__VMLINUX:
+	case DSO_BINARY_TYPE__GUEST_VMLINUX:
+	case DSO_BINARY_TYPE__DEBUGLINK:
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
+	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
+	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
+	case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
+	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
+	case DSO_BINARY_TYPE__GNU_DEBUGDATA:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
+	case DSO_BINARY_TYPE__GUEST_KMODULE:
+	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
+	case DSO_BINARY_TYPE__KCORE:
+	case DSO_BINARY_TYPE__GUEST_KCORE:
+	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
+	case DSO_BINARY_TYPE__NOT_FOUND:
+	default:
+		return true;
+	}
+}
+
+int dso__read_binary_type_filename(const struct dso *dso,
+				   enum dso_binary_type type,
+				   const char *root_dir, char *filename, size_t size)
+{
+	char build_id_hex[SBUILD_ID_SIZE];
+	int ret = 0;
+	size_t len;
+
+	switch (type) {
+	case DSO_BINARY_TYPE__DEBUGLINK:
+	{
+		const char *last_slash;
+		char dso_dir[PATH_MAX];
+		char symfile[PATH_MAX];
+		unsigned int i;
+
+		len = __symbol__join_symfs(filename, size, dso__long_name(dso));
+		last_slash = filename + len;
+		while (last_slash != filename && *last_slash != '/')
+			last_slash--;
+
+		strncpy(dso_dir, filename, last_slash - filename);
+		dso_dir[last_slash-filename] = '\0';
+
+		if (!is_regular_file(filename)) {
+			ret = -1;
+			break;
+		}
+
+		ret = filename__read_debuglink(filename, symfile, PATH_MAX);
+		if (ret)
+			break;
+
+		/* Check predefined locations where debug file might reside */
+		ret = -1;
+		for (i = 0; i < ARRAY_SIZE(debuglink_paths); i++) {
+			snprintf(filename, size,
+					debuglink_paths[i], dso_dir, symfile);
+			if (is_regular_file(filename)) {
+				ret = 0;
+				break;
+			}
+		}
+
+		break;
+	}
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
+		if (dso__build_id_filename(dso, filename, size, false) == NULL)
+			ret = -1;
+		break;
+
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
+		if (dso__build_id_filename(dso, filename, size, true) == NULL)
+			ret = -1;
+		break;
+
+	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
+		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+		snprintf(filename + len, size - len, "%s.debug", dso__long_name(dso));
+		break;
+
+	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
+		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+		snprintf(filename + len, size - len, "%s", dso__long_name(dso));
+		break;
+
+	case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
+		/*
+		 * Ubuntu can mixup /usr/lib with /lib, putting debuginfo in
+		 * /usr/lib/debug/lib when it is expected to be in
+		 * /usr/lib/debug/usr/lib
+		 */
+		if (strlen(dso__long_name(dso)) < 9 ||
+		    strncmp(dso__long_name(dso), "/usr/lib/", 9)) {
+			ret = -1;
+			break;
+		}
+		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+		snprintf(filename + len, size - len, "%s", dso__long_name(dso) + 4);
+		break;
+
+	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
+	{
+		const char *last_slash;
+		size_t dir_size;
+
+		last_slash = dso__long_name(dso) + dso__long_name_len(dso);
+		while (last_slash != dso__long_name(dso) && *last_slash != '/')
+			last_slash--;
+
+		len = __symbol__join_symfs(filename, size, "");
+		dir_size = last_slash - dso__long_name(dso) + 2;
+		if (dir_size > (size - len)) {
+			ret = -1;
+			break;
+		}
+		len += scnprintf(filename + len, dir_size, "%s",  dso__long_name(dso));
+		len += scnprintf(filename + len , size - len, ".debug%s",
+								last_slash);
+		break;
+	}
+
+	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
+		if (!dso__has_build_id(dso)) {
+			ret = -1;
+			break;
+		}
+
+		build_id__snprintf(dso__bid(dso), build_id_hex, sizeof(build_id_hex));
+		len = __symbol__join_symfs(filename, size, "/usr/lib/debug/.build-id/");
+		snprintf(filename + len, size - len, "%.2s/%s.debug",
+			 build_id_hex, build_id_hex + 2);
+		break;
+
+	case DSO_BINARY_TYPE__VMLINUX:
+	case DSO_BINARY_TYPE__GUEST_VMLINUX:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
+	case DSO_BINARY_TYPE__GNU_DEBUGDATA:
+		__symbol__join_symfs(filename, size, dso__long_name(dso));
+		break;
+
+	case DSO_BINARY_TYPE__GUEST_KMODULE:
+	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
+		path__join3(filename, size, symbol_conf.symfs,
+			    root_dir, dso__long_name(dso));
+		break;
+
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
+		__symbol__join_symfs(filename, size, dso__long_name(dso));
+		break;
+
+	case DSO_BINARY_TYPE__KCORE:
+	case DSO_BINARY_TYPE__GUEST_KCORE:
+		snprintf(filename, size, "%s", dso__long_name(dso));
+		break;
+
+	default:
+	case DSO_BINARY_TYPE__KALLSYMS:
+	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
+	case DSO_BINARY_TYPE__JAVA_JIT:
+	case DSO_BINARY_TYPE__BPF_PROG_INFO:
+	case DSO_BINARY_TYPE__BPF_IMAGE:
+	case DSO_BINARY_TYPE__OOL:
+	case DSO_BINARY_TYPE__NOT_FOUND:
+		ret = -1;
+		break;
+	}
+
+	return ret;
+}
+
+enum {
+	COMP_ID__NONE = 0,
+};
+
+static const struct {
+	const char *fmt;
+	int (*decompress)(const char *input, int output);
+	bool (*is_compressed)(const char *input);
+} compressions[] = {
+	[COMP_ID__NONE] = { .fmt = NULL, },
+#ifdef HAVE_ZLIB_SUPPORT
+	{ "gz", gzip_decompress_to_file, gzip_is_compressed },
+#endif
+#ifdef HAVE_LZMA_SUPPORT
+	{ "xz", lzma_decompress_to_file, lzma_is_compressed },
+#endif
+	{ NULL, NULL, NULL },
+};
+
+static int is_supported_compression(const char *ext)
+{
+	unsigned i;
+
+	for (i = 1; compressions[i].fmt; i++) {
+		if (!strcmp(ext, compressions[i].fmt))
+			return i;
+	}
+	return COMP_ID__NONE;
+}
+
+bool is_kernel_module(const char *pathname, int cpumode)
+{
+	struct kmod_path m;
+	int mode = cpumode & PERF_RECORD_MISC_CPUMODE_MASK;
+
+	WARN_ONCE(mode != cpumode,
+		  "Internal error: passing unmasked cpumode (%x) to is_kernel_module",
+		  cpumode);
+
+	switch (mode) {
+	case PERF_RECORD_MISC_USER:
+	case PERF_RECORD_MISC_HYPERVISOR:
+	case PERF_RECORD_MISC_GUEST_USER:
+		return false;
+	/* Treat PERF_RECORD_MISC_CPUMODE_UNKNOWN as kernel */
+	default:
+		if (kmod_path__parse(&m, pathname)) {
+			pr_err("Failed to check whether %s is a kernel module or not. Assume it is.",
+					pathname);
+			return true;
+		}
+	}
+
+	return m.kmod;
+}
+
+bool dso__needs_decompress(struct dso *dso)
+{
+	return dso__symtab_type(dso) == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP ||
+		dso__symtab_type(dso) == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;
+}
+
+int filename__decompress(const char *name, char *pathname,
+			 size_t len, int comp, int *err)
+{
+	char tmpbuf[] = KMOD_DECOMP_NAME;
+	int fd = -1;
+
+	/*
+	 * We have proper compression id for DSO and yet the file
+	 * behind the 'name' can still be plain uncompressed object.
+	 *
+	 * The reason is behind the logic we open the DSO object files,
+	 * when we try all possible 'debug' objects until we find the
+	 * data. So even if the DSO is represented by 'krava.xz' module,
+	 * we can end up here opening ~/.debug/....23432432/debug' file
+	 * which is not compressed.
+	 *
+	 * To keep this transparent, we detect this and return the file
+	 * descriptor to the uncompressed file.
+	 */
+	if (!compressions[comp].is_compressed(name)) {
+		fd = open(name, O_RDONLY | O_CLOEXEC);
+		if (fd < 0)
+			*err = errno;
+		if (pathname && len > 0)
+			pathname[0] = '\0';
+		return fd;
+	}
+
+	fd = mkostemp(tmpbuf, O_CLOEXEC);
+	if (fd < 0) {
+		*err = errno;
+		return -1;
+	}
+
+	if (compressions[comp].decompress(name, fd)) {
+		*err = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
+		close(fd);
+		fd = -1;
+	}
+
+	if (!pathname || (fd < 0))
+		unlink(tmpbuf);
+
+	if (pathname && (fd >= 0))
+		strlcpy(pathname, tmpbuf, len);
+
+	return fd;
+}
+
+static int decompress_kmodule(struct dso *dso, const char *name,
+			      char *pathname, size_t len)
+{
+	if (!dso__needs_decompress(dso))
+		return -1;
+
+	if (dso__comp(dso) == COMP_ID__NONE)
+		return -1;
+
+	return filename__decompress(name, pathname, len, dso__comp(dso), dso__load_errno(dso));
+}
+
+int dso__decompress_kmodule_fd(struct dso *dso, const char *name)
+{
+	return decompress_kmodule(dso, name, NULL, 0);
+}
+
+int dso__decompress_kmodule_path(struct dso *dso, const char *name,
+				 char *pathname, size_t len)
+{
+	int fd = decompress_kmodule(dso, name, pathname, len);
+
+	/* decompress_kmodule() returns -1 on failure, don't close(-1) */
+	if (fd >= 0)
+		close(fd);
+	return fd >= 0 ? 0 : -1;
+}
+
+/*
+ * Parses kernel module specified in @path and updates
+ * @m argument like:
+ *
+ *    @comp - true if @path contains supported compression suffix,
+ *            false otherwise
+ *    @kmod - true if @path contains '.ko' suffix in right position,
+ *            false otherwise
+ *    @name - if (@alloc_name && @kmod) is true, it contains strdup-ed base name
+ *            of the kernel module without suffixes, otherwise strudup-ed
+ *            base name of @path
+ *    @ext  - if (@alloc_ext && @comp) is true, it contains strdup-ed string
+ *            the compression suffix
+ *
+ * Returns 0 if there's no strdup error, -ENOMEM otherwise.
+ */
+int __kmod_path__parse(struct kmod_path *m, const char *path,
+		       bool alloc_name)
+{
+	const char *name = strrchr(path, '/');
+	const char *ext  = strrchr(path, '.');
+	bool is_simple_name = false;
+
+	memset(m, 0x0, sizeof(*m));
+	name = name ? name + 1 : path;
+
+	/*
+	 * '.' is also a valid character for module name. For example:
+	 * [aaa.bbb] is a valid module name. '[' should have higher
+	 * priority than '.ko' suffix.
+	 *
+	 * The kernel names are from machine__mmap_name. Such
+	 * name should belong to kernel itself, not kernel module.
+	 */
+	if (name[0] == '[') {
+		is_simple_name = true;
+		if ((strncmp(name, "[kernel.kallsyms]", 17) == 0) ||
+		    (strncmp(name, "[guest.kernel.kallsyms", 22) == 0) ||
+		    (strncmp(name, "[vdso]", 6) == 0) ||
+		    (strncmp(name, "[vdso32]", 8) == 0) ||
+		    (strncmp(name, "[vdsox32]", 9) == 0) ||
+		    (strncmp(name, "[vsyscall]", 10) == 0)) {
+			m->kmod = false;
+
+		} else
+			m->kmod = true;
+	}
+
+	/* No extension, just return name. */
+	if ((ext == NULL) || is_simple_name) {
+		if (alloc_name) {
+			m->name = strdup(name);
+			return m->name ? 0 : -ENOMEM;
+		}
+		return 0;
+	}
+
+	m->comp = is_supported_compression(ext + 1);
+	if (m->comp > COMP_ID__NONE)
+		ext -= 3;
+
+	/* Check .ko extension only if there's enough name left. */
+	if (ext > name)
+		m->kmod = !strncmp(ext, ".ko", 3);
+
+	if (alloc_name) {
+		if (m->kmod) {
+			if (asprintf(&m->name, "[%.*s]", (int) (ext - name), name) == -1)
+				return -ENOMEM;
+		} else {
+			if (asprintf(&m->name, "%s", name) == -1)
+				return -ENOMEM;
+		}
+
+		strreplace(m->name, '-', '_');
+	}
+
+	return 0;
+}
+
+void dso__set_module_info(struct dso *dso, struct kmod_path *m,
+			  struct machine *machine)
+{
+	if (machine__is_host(machine))
+		dso__set_symtab_type(dso, DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE);
+	else
+		dso__set_symtab_type(dso, DSO_BINARY_TYPE__GUEST_KMODULE);
+
+	/* _KMODULE_COMP should be next to _KMODULE */
+	if (m->kmod && m->comp) {
+		dso__set_symtab_type(dso, dso__symtab_type(dso) + 1);
+		dso__set_comp(dso, m->comp);
+	}
+
+	dso__set_is_kmod(dso);
+	dso__set_short_name(dso, strdup(m->name), true);
+}
+
+/*
+ * Global list of open DSOs and the counter.
+ */
+struct mutex _dso__data_open_lock;
+static LIST_HEAD(dso__data_open);
+static long dso__data_open_cnt GUARDED_BY(_dso__data_open_lock);
+
+static void dso__data_open_lock_init(void)
+{
+	mutex_init(&_dso__data_open_lock);
+}
+
+static struct mutex *dso__data_open_lock(void) LOCK_RETURNED(_dso__data_open_lock)
+{
+	static pthread_once_t data_open_lock_once = PTHREAD_ONCE_INIT;
+
+	pthread_once(&data_open_lock_once, dso__data_open_lock_init);
+
+	return &_dso__data_open_lock;
+}
+
+static void dso__list_add(struct dso *dso) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	list_add_tail(&dso__data(dso)->open_entry, &dso__data_open);
+#ifdef REFCNT_CHECKING
+	dso__data(dso)->dso = dso__get(dso);
+#endif
+	/* Assume the dso is part of dsos, hence the optional reference count above. */
+	assert(dso__dsos(dso));
+	dso__data_open_cnt++;
+}
+
+static void dso__list_del(struct dso *dso) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	list_del_init(&dso__data(dso)->open_entry);
+#ifdef REFCNT_CHECKING
+	mutex_unlock(dso__data_open_lock());
+	dso__put(dso__data(dso)->dso);
+	mutex_lock(dso__data_open_lock());
+#endif
+	WARN_ONCE(dso__data_open_cnt <= 0,
+		  "DSO data fd counter out of bounds.");
+	dso__data_open_cnt--;
+}
+
+static void close_first_dso(void);
+
+static int do_open(char *name) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	do {
+		int fd = open(name, O_RDONLY|O_CLOEXEC);
+
+		if (fd >= 0)
+			return fd;
+
+		pr_debug("dso open failed: %m\n");
+		if (!dso__data_open_cnt || errno != EMFILE)
+			break;
+
+		close_first_dso();
+	} while (1);
+
+	return -1;
+}
+
+char *dso__filename_with_chroot(const struct dso *dso, const char *filename)
+{
+	return filename_with_chroot(nsinfo__pid(dso__nsinfo_const(dso)), filename);
+}
+
+static char *dso__get_filename(struct dso *dso, const char *root_dir,
+			       bool *decomp)
+{
+	char *name = malloc(PATH_MAX);
+
+	*decomp = false;
+
+	if (name == NULL)
+		return NULL;
+
+	if (dso__read_binary_type_filename(dso, dso__binary_type(dso),
+					    root_dir, name, PATH_MAX))
+		goto out;
+
+	if (!is_regular_file(name)) {
+		struct stat st;
+		char *new_name;
+
+		/*
+		 * errno only reflects the failure reason when stat() itself
+		 * failed: a successful stat() on a non-regular file (e.g. a
+		 * directory) leaves a stale errno, which a previous failed
+		 * iteration of the try_to_open_dso() fallback loop may have
+		 * set to ENOENT.
+		 */
+		if (stat(name, &st) == 0 || errno != ENOENT ||
+		    dso__nsinfo(dso) == NULL)
+			goto out;
+
+		new_name = dso__filename_with_chroot(dso, name);
+		if (!new_name)
+			goto out;
+
+		free(name);
+		name = new_name;
+	}
+
+	if (dso__needs_decompress(dso)) {
+		char newpath[KMOD_DECOMP_LEN];
+		size_t len = sizeof(newpath);
+
+		if (dso__decompress_kmodule_path(dso, name, newpath, len) < 0) {
+			/*
+			 * Use a standard errno value, not the negative custom
+			 * DSO_LOAD_ERRNO stored in dso__load_errno(dso):
+			 * __open_dso() computes fd = -errno, so a negative
+			 * errno produces a positive fd that looks valid.
+			 */
+			errno = EIO;
+			goto out;
+		}
+
+		/* empty pathname means file wasn't actually compressed */
+		if (newpath[0] != '\0') {
+			char *tmp = strdup(newpath);
+
+			if (!tmp) {
+				unlink(newpath);
+				goto out;
+			}
+			free(name);
+			name = tmp;
+			*decomp = true;
+		}
+	}
+	return name;
+
+out:
+	free(name);
+	return NULL;
+}
+
+static int __open_dso(struct dso *dso, struct machine *machine)
+	EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	int fd = -EINVAL;
+	char *name;
+	bool decomp = false;
+
+	mutex_lock(dso__lock(dso));
+
+	name = dso__get_filename(dso, machine ? machine->root_dir : "", &decomp);
+	if (name) {
+		fd = do_open(name);
+	} else {
+		if (errno == 0)
+			errno = ENOENT;
+		fd = -errno;
+	}
+
+	if (decomp)
+		unlink(name);
+
+	mutex_unlock(dso__lock(dso));
+	free(name);
+	return fd;
+}
+
+static void check_data_close(void);
+
+/**
+ * dso_close - Open DSO data file
+ * @dso: dso object
+ *
+ * Open @dso's data file descriptor and updates
+ * list/count of open DSO objects.
+ */
+static int open_dso(struct dso *dso, struct machine *machine)
+	EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	int fd;
+	struct nscookie nsc;
+
+	if (dso__binary_type(dso) != DSO_BINARY_TYPE__BUILD_ID_CACHE) {
+		mutex_lock(dso__lock(dso));
+		nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+		mutex_unlock(dso__lock(dso));
+	}
+	fd = __open_dso(dso, machine);
+	if (dso__binary_type(dso) != DSO_BINARY_TYPE__BUILD_ID_CACHE)
+		nsinfo__mountns_exit(&nsc);
+
+	if (fd >= 0) {
+		dso__list_add(dso);
+		/*
+		 * Check if we crossed the allowed number
+		 * of opened DSOs and close one if needed.
+		 */
+		check_data_close();
+	}
+
+	return fd;
+}
+
+static void close_data_fd(struct dso *dso) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	if (dso__data(dso)->fd >= 0) {
+		close(dso__data(dso)->fd);
+		dso__data(dso)->fd = -1;
+		dso__data(dso)->file_size = 0;
+		dso__list_del(dso);
+	}
+}
+
+/**
+ * dso_close - Close DSO data file
+ * @dso: dso object
+ *
+ * Close @dso's data file descriptor and updates
+ * list/count of open DSO objects.
+ */
+static void close_dso(struct dso *dso) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	close_data_fd(dso);
+}
+
+static void close_first_dso(void) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	struct dso_data *dso_data;
+	struct dso *dso;
+
+	dso_data = list_first_entry(&dso__data_open, struct dso_data, open_entry);
+#ifdef REFCNT_CHECKING
+	dso = dso_data->dso;
+#else
+	dso = container_of(dso_data, struct dso, data);
+#endif
+	close_dso(dso);
+}
+
+static rlim_t get_fd_limit(void)
+{
+	struct rlimit l;
+	rlim_t limit = 0;
+
+	/* Allow half of the current open fd limit. */
+	if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
+		if (l.rlim_cur == RLIM_INFINITY)
+			limit = l.rlim_cur;
+		else
+			limit = l.rlim_cur / 2;
+	} else {
+		pr_err("failed to get fd limit\n");
+		limit = 1;
+	}
+
+	return limit;
+}
+
+static rlim_t fd_limit;
+
+/*
+ * Used only by tests/dso-data.c to reset the environment
+ * for tests. I dont expect we should change this during
+ * standard runtime.
+ */
+void reset_fd_limit(void)
+{
+	fd_limit = 0;
+}
+
+static bool may_cache_fd(void) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	if (!fd_limit)
+		fd_limit = get_fd_limit();
+
+	if (fd_limit == RLIM_INFINITY)
+		return true;
+
+	return fd_limit > (rlim_t) dso__data_open_cnt;
+}
+
+/*
+ * Check and close LRU dso if we crossed allowed limit
+ * for opened dso file descriptors. The limit is half
+ * of the RLIMIT_NOFILE files opened.
+*/
+static void check_data_close(void) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	bool cache_fd = may_cache_fd();
+
+	if (!cache_fd)
+		close_first_dso();
+}
+
+/**
+ * dso__data_close - Close DSO data file
+ * @dso: dso object
+ *
+ * External interface to close @dso's data file descriptor.
+ */
+void dso__data_close(struct dso *dso)
+{
+	mutex_lock(dso__data_open_lock());
+	close_dso(dso);
+	mutex_unlock(dso__data_open_lock());
+}
+
+static void try_to_open_dso(struct dso *dso, struct machine *machine)
+	EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	enum dso_binary_type binary_type_data[] = {
+		DSO_BINARY_TYPE__BUILD_ID_CACHE,
+		DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
+		DSO_BINARY_TYPE__NOT_FOUND,
+	};
+	int i = 0;
+	struct dso_data *dso_data = dso__data(dso);
+
+	if (dso_data->fd >= 0)
+		return;
+
+	if (dso__binary_type(dso) != DSO_BINARY_TYPE__NOT_FOUND) {
+		dso_data->fd = open_dso(dso, machine);
+		goto out;
+	}
+
+	do {
+		dso__set_binary_type(dso, binary_type_data[i++]);
+
+		dso_data->fd = open_dso(dso, machine);
+		if (dso_data->fd >= 0)
+			goto out;
+
+	} while (dso__binary_type(dso) != DSO_BINARY_TYPE__NOT_FOUND);
+out:
+	if (dso_data->fd >= 0)
+		dso_data->status = DSO_DATA_STATUS_OK;
+	else
+		dso_data->status = DSO_DATA_STATUS_ERROR;
+}
+
+/**
+ * dso__data_get_fd - Get dso's data file descriptor
+ * @dso: dso object
+ * @machine: machine object
+ *
+ * External interface to find dso's file, open it and
+ * returns file descriptor.  It should be paired with
+ * dso__data_put_fd() if it returns non-negative value.
+ */
+bool dso__data_get_fd(struct dso *dso, struct machine *machine, int *fd)
+{
+	*fd = -1;
+	if (dso__data(dso)->status == DSO_DATA_STATUS_ERROR)
+		return false;
+
+	mutex_lock(dso__data_open_lock());
+
+	try_to_open_dso(dso, machine);
+
+	*fd = dso__data(dso)->fd;
+	if (*fd >= 0)
+		return true;
+
+	mutex_unlock(dso__data_open_lock());
+	return false;
+}
+
+void dso__data_put_fd(struct dso *dso __maybe_unused)
+{
+	mutex_unlock(dso__data_open_lock());
+}
+
+bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by)
+{
+	u32 flag = 1 << by;
+
+	if (dso__data(dso)->status_seen & flag)
+		return true;
+
+	dso__data(dso)->status_seen |= flag;
+
+	return false;
+}
+
+#ifdef HAVE_LIBBPF_SUPPORT
+static ssize_t bpf_read(struct dso *dso, u64 offset, char *data)
+{
+	struct bpf_prog_info_node *node;
+	ssize_t size = DSO__DATA_CACHE_SIZE;
+	struct dso_bpf_prog *dso_bpf_prog = dso__bpf_prog(dso);
+	u64 len;
+	u8 *buf;
+
+	node = perf_env__find_bpf_prog_info(dso_bpf_prog->env, dso_bpf_prog->id);
+	if (!node || !node->info_linear) {
+		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
+		return -1;
+	}
+
+	/* jited_prog_insns is only valid if bpil_offs_to_addr() converted it */
+	if (!(node->info_linear->arrays & (1UL << PERF_BPIL_JITED_INSNS))) {
+		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
+		return -1;
+	}
+
+	len = node->info_linear->info.jited_prog_len;
+	buf = (u8 *)(uintptr_t)node->info_linear->info.jited_prog_insns;
+
+	if (offset >= len)
+		return -1;
+
+	size = (ssize_t)min(len - offset, (u64)size);
+	memcpy(data, buf + offset, size);
+	return size;
+}
+
+static int bpf_size(struct dso *dso)
+{
+	struct bpf_prog_info_node *node;
+	struct dso_bpf_prog *dso_bpf_prog = dso__bpf_prog(dso);
+
+	node = perf_env__find_bpf_prog_info(dso_bpf_prog->env, dso_bpf_prog->id);
+	if (!node || !node->info_linear) {
+		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
+		return -1;
+	}
+
+	dso__data(dso)->file_size = node->info_linear->info.jited_prog_len;
+	return 0;
+}
+#endif // HAVE_LIBBPF_SUPPORT
+
+static void
+dso_cache__free(struct dso *dso)
+{
+	struct rb_root *root = &dso__data(dso)->cache;
+	struct rb_node *next = rb_first(root);
+
+	mutex_lock(dso__lock(dso));
+	while (next) {
+		struct dso_cache *cache;
+
+		cache = rb_entry(next, struct dso_cache, rb_node);
+		next = rb_next(&cache->rb_node);
+		rb_erase(&cache->rb_node, root);
+		free(cache);
+	}
+	mutex_unlock(dso__lock(dso));
+}
+
+static struct dso_cache *__dso_cache__find(struct dso *dso, u64 offset)
+{
+	const struct rb_root *root = &dso__data(dso)->cache;
+	struct rb_node * const *p = &root->rb_node;
+	const struct rb_node *parent = NULL;
+	struct dso_cache *cache;
+
+	while (*p != NULL) {
+		u64 end;
+
+		parent = *p;
+		cache = rb_entry(parent, struct dso_cache, rb_node);
+		end = cache->offset + DSO__DATA_CACHE_SIZE;
+
+		if (offset < cache->offset)
+			p = &(*p)->rb_left;
+		else if (offset >= end)
+			p = &(*p)->rb_right;
+		else
+			return cache;
+	}
+
+	return NULL;
+}
+
+static struct dso_cache *
+dso_cache__insert(struct dso *dso, struct dso_cache *new)
+{
+	struct rb_root *root = &dso__data(dso)->cache;
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct dso_cache *cache;
+	u64 offset = new->offset;
+
+	mutex_lock(dso__lock(dso));
+	while (*p != NULL) {
+		u64 end;
+
+		parent = *p;
+		cache = rb_entry(parent, struct dso_cache, rb_node);
+		end = cache->offset + DSO__DATA_CACHE_SIZE;
+
+		if (offset < cache->offset)
+			p = &(*p)->rb_left;
+		else if (offset >= end)
+			p = &(*p)->rb_right;
+		else
+			goto out;
+	}
+
+	rb_link_node(&new->rb_node, parent, p);
+	rb_insert_color(&new->rb_node, root);
+
+	cache = NULL;
+out:
+	mutex_unlock(dso__lock(dso));
+	return cache;
+}
+
+static ssize_t dso_cache__memcpy(struct dso_cache *cache, u64 offset, u8 *data,
+				 u64 size, bool out)
+{
+	u64 cache_offset = offset - cache->offset;
+	u64 cache_size;
+
+	/*
+	 * The RB tree matches using DSO__DATA_CACHE_SIZE, but a short
+	 * pread may leave cache->size smaller.  For a regular file a
+	 * short pread only happens at end-of-file, so an offset past
+	 * the valid data is EOF: return 0, matching what a direct
+	 * pread() at that offset would return, and cached_io() then
+	 * stops its read loop.
+	 */
+	if (cache_offset >= cache->size)
+		return 0;
+
+	cache_size = min(cache->size - cache_offset, size);
+
+	if (out)
+		memcpy(data, cache->data + cache_offset, cache_size);
+	else
+		memcpy(cache->data + cache_offset, data, cache_size);
+	return cache_size;
+}
+
+static ssize_t file_read(struct dso *dso, struct machine *machine,
+			 u64 offset, char *data)
+{
+	ssize_t ret;
+
+	mutex_lock(dso__data_open_lock());
+
+	/*
+	 * dso__data(dso)->fd might be closed if other thread opened another
+	 * file (dso) due to open file limit (RLIMIT_NOFILE).
+	 */
+	try_to_open_dso(dso, machine);
+
+	if (dso__data(dso)->fd < 0) {
+		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
+		ret = dso__data(dso)->fd;
+		goto out;
+	}
+
+	ret = pread(dso__data(dso)->fd, data, DSO__DATA_CACHE_SIZE, offset);
+out:
+	mutex_unlock(dso__data_open_lock());
+	return ret;
+}
+
+static struct dso_cache *dso_cache__populate(struct dso *dso,
+					     struct machine *machine,
+					     u64 offset, ssize_t *ret)
+{
+	u64 cache_offset = offset & DSO__DATA_CACHE_MASK;
+	struct dso_cache *cache;
+	struct dso_cache *old;
+
+	cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);
+	if (!cache) {
+		*ret = -ENOMEM;
+		return NULL;
+	}
+#ifdef HAVE_LIBBPF_SUPPORT
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO)
+		*ret = bpf_read(dso, cache_offset, cache->data);
+	else
+#endif
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__OOL)
+		*ret = DSO__DATA_CACHE_SIZE;
+	else
+		*ret = file_read(dso, machine, cache_offset, cache->data);
+
+	if (*ret <= 0) {
+		free(cache);
+		return NULL;
+	}
+
+	cache->offset = cache_offset;
+	cache->size   = *ret;
+
+	old = dso_cache__insert(dso, cache);
+	if (old) {
+		/* we lose the race */
+		free(cache);
+		cache = old;
+	}
+
+	return cache;
+}
+
+static struct dso_cache *dso_cache__find(struct dso *dso,
+					 struct machine *machine,
+					 u64 offset,
+					 ssize_t *ret)
+{
+	struct dso_cache *cache = __dso_cache__find(dso, offset);
+
+	return cache ? cache : dso_cache__populate(dso, machine, offset, ret);
+}
+
+static ssize_t dso_cache_io(struct dso *dso, struct machine *machine,
+			    u64 offset, u8 *data, ssize_t size, bool out)
+{
+	struct dso_cache *cache;
+	ssize_t ret = 0;
+
+	cache = dso_cache__find(dso, machine, offset, &ret);
+	if (!cache)
+		return ret;
+
+	return dso_cache__memcpy(cache, offset, data, size, out);
+}
+
+/*
+ * Reads and caches dso data DSO__DATA_CACHE_SIZE size chunks
+ * in the rb_tree. Any read to already cached data is served
+ * by cached data. Writes update the cache only, not the backing file.
+ */
+static ssize_t cached_io(struct dso *dso, struct machine *machine,
+			 u64 offset, u8 *data, ssize_t size, bool out)
+{
+	ssize_t r = 0;
+	u8 *p = data;
+
+	do {
+		ssize_t ret;
+
+		ret = dso_cache_io(dso, machine, offset, p, size, out);
+		if (ret < 0)
+			return ret;
+
+		/* Reached EOF, return what we have. */
+		if (!ret)
+			break;
+
+		BUG_ON(ret > size);
+
+		r      += ret;
+		p      += ret;
+		offset += ret;
+		size   -= ret;
+
+	} while (size);
+
+	return r;
+}
+
+static int file_size(struct dso *dso, struct machine *machine)
+{
+	int ret = 0;
+	struct stat st;
+
+	mutex_lock(dso__data_open_lock());
+
+	/*
+	 * dso__data(dso)->fd might be closed if other thread opened another
+	 * file (dso) due to open file limit (RLIMIT_NOFILE).
+	 */
+	try_to_open_dso(dso, machine);
+
+	if (dso__data(dso)->fd < 0) {
+		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
+		ret = dso__data(dso)->fd;
+		goto out;
+	}
+
+	if (fstat(dso__data(dso)->fd, &st) < 0) {
+		ret = -errno;
+		pr_err("dso cache fstat failed: %m\n");
+		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
+		goto out;
+	}
+	dso__data(dso)->file_size = st.st_size;
+
+out:
+	mutex_unlock(dso__data_open_lock());
+	return ret;
+}
+
+int dso__data_file_size(struct dso *dso, struct machine *machine)
+{
+	if (dso__data(dso)->file_size)
+		return 0;
+
+	if (dso__data(dso)->status == DSO_DATA_STATUS_ERROR)
+		return -1;
+#ifdef HAVE_LIBBPF_SUPPORT
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO)
+		return bpf_size(dso);
+#endif
+	return file_size(dso, machine);
+}
+
+/**
+ * dso__data_size - Return dso data size
+ * @dso: dso object
+ * @machine: machine object
+ *
+ * Return: dso data size
+ */
+off_t dso__data_size(struct dso *dso, struct machine *machine)
+{
+	if (dso__data_file_size(dso, machine))
+		return -1;
+
+	/* For now just estimate dso data size is close to file size */
+	return dso__data(dso)->file_size;
+}
+
+static ssize_t data_read_write_offset(struct dso *dso, struct machine *machine,
+				      u64 offset, u8 *data, ssize_t size,
+				      bool out)
+{
+	if (dso__data_file_size(dso, machine))
+		return -1;
+
+	/* Check the offset sanity. */
+	if (offset > dso__data(dso)->file_size)
+		return -1;
+
+	if (offset + size < offset)
+		return -1;
+
+	return cached_io(dso, machine, offset, data, size, out);
+}
+
+/**
+ * dso__data_read_offset - Read data from dso file offset
+ * @dso: dso object
+ * @machine: machine object
+ * @offset: file offset
+ * @data: buffer to store data
+ * @size: size of the @data buffer
+ *
+ * External interface to read data from dso file offset. Open
+ * dso data file and use cached_read to get the data.
+ */
+ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
+			      u64 offset, u8 *data, ssize_t size)
+{
+	if (dso__data(dso)->status == DSO_DATA_STATUS_ERROR)
+		return -1;
+
+	return data_read_write_offset(dso, machine, offset, data, size, true);
+}
+
+static enum dso_swap_type dso_swap_type__from_elf_data(unsigned char eidata)
+{
+	static const unsigned int endian = 1;
+
+	switch (eidata) {
+	case ELFDATA2LSB:
+		/* We are big endian, DSO is little endian. */
+		return (*(unsigned char const *)&endian != 1) ? DSO_SWAP__YES : DSO_SWAP__NO;
+	case ELFDATA2MSB:
+		/* We are little endian, DSO is big endian. */
+		return (*(unsigned char const *)&endian != 0) ? DSO_SWAP__YES : DSO_SWAP__NO;
+	default:
+		return DSO_SWAP__UNSET;
+	}
+}
+
+/* Reads e_machine from fd, optionally caching data in dso. */
+uint16_t dso__read_e_machine_endian(struct dso *optional_dso, int fd, uint32_t *e_flags,
+				    bool *is_big_endian)
+{
+	uint16_t e_machine = EM_NONE;
+	unsigned char e_ident[EI_NIDENT];
+	enum dso_swap_type swap_type;
+	bool need_e_flags;
+
+	if (e_flags)
+		*e_flags = 0;
+
+	{
+		_Static_assert(offsetof(Elf32_Ehdr, e_ident) == 0, "Unexpected offset");
+		_Static_assert(offsetof(Elf64_Ehdr, e_ident) == 0, "Unexpected offset");
+	}
+	if (pread(fd, &e_ident, sizeof(e_ident), 0) != sizeof(e_ident))
+		return EM_NONE; // Read failed.
+
+	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0)
+		return EM_NONE; // Not an ELF file.
+
+	if (e_ident[EI_CLASS] == ELFCLASSNONE || e_ident[EI_CLASS] >= ELFCLASSNUM)
+		return EM_NONE; // Bad ELF class (32 or 64-bit objects).
+
+	if (e_ident[EI_VERSION] != EV_CURRENT)
+		return EM_NONE; // Bad ELF version.
+
+	swap_type = dso_swap_type__from_elf_data(e_ident[EI_DATA]);
+	if (swap_type == DSO_SWAP__UNSET)
+		return EM_NONE; // Bad ELF data encoding.
+
+	if (is_big_endian)
+		*is_big_endian = (e_ident[EI_DATA] == ELFDATA2MSB);
+
+	/* Cache the need for swapping. */
+	if (optional_dso) {
+		assert(dso__needs_swap(optional_dso) == DSO_SWAP__UNSET ||
+		       dso__needs_swap(optional_dso) == swap_type);
+		dso__set_needs_swap(optional_dso, swap_type);
+	}
+
+	{
+		_Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, "Unexpected offset");
+		_Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, "Unexpected offset");
+	}
+	if (pread(fd, &e_machine, sizeof(e_machine), 18) != sizeof(e_machine))
+		return EM_NONE; // e_machine read failed.
+
+	e_machine = DSO_SWAP_TYPE__SWAP(swap_type, uint16_t, e_machine);
+	if (e_machine >= EM_NUM)
+		return EM_NONE; // Bad ELF machine number.
+
+#ifdef NDEBUG
+	/* In production code the e_flags are only needed on CSKY. */
+	need_e_flags = e_flags && e_machine == EM_CSKY;
+#else
+	/* Debug code will always read the e_flags. */
+	need_e_flags = e_flags != NULL;
+#endif
+	if (need_e_flags) {
+		off_t offset = e_ident[EI_CLASS] == ELFCLASS32
+			? offsetof(Elf32_Ehdr, e_flags)
+			: offsetof(Elf64_Ehdr, e_flags);
+
+		if (pread(fd, e_flags, sizeof(*e_flags), offset) != sizeof(*e_flags)) {
+			*e_flags = 0;
+			return EM_NONE; // e_flags read failed.
+		}
+	}
+	return e_machine;
+}
+
+uint16_t dso__e_machine_endian(struct dso *dso, struct machine *machine, uint32_t *e_flags,
+			       bool *is_big_endian)
+{
+	uint16_t e_machine = EM_NONE;
+	int fd;
+
+	switch (dso__binary_type(dso)) {
+	case DSO_BINARY_TYPE__KALLSYMS:
+	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
+	case DSO_BINARY_TYPE__VMLINUX:
+	case DSO_BINARY_TYPE__GUEST_VMLINUX:
+	case DSO_BINARY_TYPE__GUEST_KMODULE:
+	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
+	case DSO_BINARY_TYPE__KCORE:
+	case DSO_BINARY_TYPE__GUEST_KCORE:
+	case DSO_BINARY_TYPE__BPF_PROG_INFO:
+	case DSO_BINARY_TYPE__BPF_IMAGE:
+	case DSO_BINARY_TYPE__OOL:
+	case DSO_BINARY_TYPE__JAVA_JIT:
+		if (is_big_endian) {
+			*is_big_endian = perf_arch_is_big_endian(
+				machine && machine->env ? perf_env__arch(machine->env) : NULL);
+		}
+		return perf_env__e_machine(machine ? machine->env : NULL, e_flags);
+	case DSO_BINARY_TYPE__DEBUGLINK:
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
+	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
+	case DSO_BINARY_TYPE__GNU_DEBUGDATA:
+	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
+	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
+	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
+	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
+	case DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO:
+	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
+		break;
+	case DSO_BINARY_TYPE__NOT_FOUND:
+	default:
+		if (e_flags)
+			*e_flags = 0;
+		return EM_NONE;
+	}
+
+	mutex_lock(dso__data_open_lock());
+
+	/*
+	 * dso__data(dso)->fd might be closed if other thread opened another
+	 * file (dso) due to open file limit (RLIMIT_NOFILE).
+	 */
+	try_to_open_dso(dso, machine);
+	fd = dso__data(dso)->fd;
+	if (fd >= 0)
+		e_machine = dso__read_e_machine_endian(dso, fd, e_flags, is_big_endian);
+	else if (e_flags)
+		*e_flags = 0;
+
+	mutex_unlock(dso__data_open_lock());
+	return e_machine;
+}
+
+/**
+ * dso__data_read_addr - Read data from dso address
+ * @dso: dso object
+ * @machine: machine object
+ * @add: virtual memory address
+ * @data: buffer to store data
+ * @size: size of the @data buffer
+ *
+ * External interface to read data from dso address.
+ */
+ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
+			    struct machine *machine, u64 addr,
+			    u8 *data, ssize_t size)
+{
+	u64 offset = map__map_ip(map, addr);
+
+	return dso__data_read_offset(dso, machine, offset, data, size);
+}
+
+/**
+ * dso__data_write_cache_offs - Write data to dso data cache at file offset
+ * @dso: dso object
+ * @machine: machine object
+ * @offset: file offset
+ * @data: buffer to write
+ * @size: size of the @data buffer
+ *
+ * Write into the dso file data cache, but do not change the file itself.
+ */
+ssize_t dso__data_write_cache_offs(struct dso *dso, struct machine *machine,
+				   u64 offset, const u8 *data_in, ssize_t size)
+{
+	u8 *data = (u8 *)data_in; /* cast away const to use same fns for r/w */
+
+	if (dso__data(dso)->status == DSO_DATA_STATUS_ERROR)
+		return -1;
+
+	return data_read_write_offset(dso, machine, offset, data, size, false);
+}
+
+/**
+ * dso__data_write_cache_addr - Write data to dso data cache at dso address
+ * @dso: dso object
+ * @machine: machine object
+ * @add: virtual memory address
+ * @data: buffer to write
+ * @size: size of the @data buffer
+ *
+ * External interface to write into the dso file data cache, but do not change
+ * the file itself.
+ */
+ssize_t dso__data_write_cache_addr(struct dso *dso, struct map *map,
+				   struct machine *machine, u64 addr,
+				   const u8 *data, ssize_t size)
+{
+	u64 offset = map__map_ip(map, addr);
+
+	return dso__data_write_cache_offs(dso, machine, offset, data, size);
+}
+
+struct map *dso__new_map(const char *name)
+{
+	struct map *map = NULL;
+	struct dso *dso = dso__new(name);
+
+	if (dso) {
+		map = map__new2(0, dso);
+		dso__put(dso);
+	}
+
+	return map;
+}
+
+struct dso *machine__findnew_kernel(struct machine *machine, const char *name,
+				    const char *short_name, int dso_type)
+{
+	/*
+	 * The kernel dso could be created by build_id processing.
+	 */
+	struct dso *dso = machine__findnew_dso(machine, name);
+
+	/*
+	 * We need to run this in all cases, since during the build_id
+	 * processing we had no idea this was the kernel dso.
+	 */
+	if (dso != NULL) {
+		dso__set_short_name(dso, short_name, false);
+		dso__set_kernel(dso, dso_type);
+	}
+
+	return dso;
+}
+
+static void __dso__set_long_name_id(struct dso *dso, const char *name, bool name_allocated)
+{
+	if (dso__long_name_allocated(dso))
+		free((char *)dso__long_name(dso));
+
+	RC_CHK_ACCESS(dso)->long_name = name;
+	RC_CHK_ACCESS(dso)->long_name_len = strlen(name);
+	dso__set_long_name_allocated(dso, name_allocated);
+}
+
+static void dso__set_long_name_id(struct dso *dso, const char *name, bool name_allocated)
+{
+	struct dsos *dsos = dso__dsos(dso);
+
+	if (name == NULL)
+		return;
+
+	if (dsos) {
+		/*
+		 * Need to avoid re-sorting the dsos breaking by non-atomically
+		 * renaming the dso.
+		 */
+		down_write(&dsos->lock);
+		__dso__set_long_name_id(dso, name, name_allocated);
+		dsos->sorted = false;
+		up_write(&dsos->lock);
+	} else {
+		__dso__set_long_name_id(dso, name, name_allocated);
+	}
+}
+
+static int __dso_id__cmp(const struct dso_id *a, const struct dso_id *b)
+{
+	if (a->mmap2_valid && b->mmap2_valid) {
+		if (a->maj > b->maj) return -1;
+		if (a->maj < b->maj) return 1;
+
+		if (a->min > b->min) return -1;
+		if (a->min < b->min) return 1;
+
+		if (a->ino > b->ino) return -1;
+		if (a->ino < b->ino) return 1;
+	}
+	if (a->mmap2_ino_generation_valid && b->mmap2_ino_generation_valid) {
+		if (a->ino_generation > b->ino_generation) return -1;
+		if (a->ino_generation < b->ino_generation) return 1;
+	}
+	if (build_id__is_defined(&a->build_id) && build_id__is_defined(&b->build_id)) {
+		if (a->build_id.size != b->build_id.size)
+			return a->build_id.size < b->build_id.size ? -1 : 1;
+		return memcmp(a->build_id.data, b->build_id.data, a->build_id.size);
+	}
+	return 0;
+}
+
+const struct dso_id dso_id_empty = {
+	{
+		.maj = 0,
+		.min = 0,
+		.ino = 0,
+		.ino_generation = 0,
+	},
+	.mmap2_valid = false,
+	.mmap2_ino_generation_valid = false,
+	{
+		.size = 0,
+	}
+};
+
+void __dso__improve_id(struct dso *dso, const struct dso_id *id)
+{
+	struct dsos *dsos = dso__dsos(dso);
+	struct dso_id *dso_id = dso__id(dso);
+	bool changed = false;
+
+	/* dsos write lock held by caller. */
+
+	if (id->mmap2_valid && !dso_id->mmap2_valid) {
+		dso_id->maj = id->maj;
+		dso_id->min = id->min;
+		dso_id->ino = id->ino;
+		dso_id->mmap2_valid = true;
+		changed = true;
+	}
+	if (id->mmap2_ino_generation_valid && !dso_id->mmap2_ino_generation_valid) {
+		dso_id->ino_generation = id->ino_generation;
+		dso_id->mmap2_ino_generation_valid = true;
+		changed = true;
+	}
+	if (build_id__is_defined(&id->build_id) && !build_id__is_defined(&dso_id->build_id)) {
+		dso_id->build_id = id->build_id;
+		changed = true;
+	}
+	if (changed && dsos)
+		dsos->sorted = false;
+}
+
+int dso_id__cmp(const struct dso_id *a, const struct dso_id *b)
+{
+	if (a == &dso_id_empty || b == &dso_id_empty) {
+		/* There is no valid data to compare so the comparison always returns identical. */
+		return 0;
+	}
+
+	return __dso_id__cmp(a, b);
+}
+
+int dso__cmp_id(struct dso *a, struct dso *b)
+{
+	return __dso_id__cmp(dso__id(a), dso__id(b));
+}
+
+void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
+{
+	dso__set_long_name_id(dso, name, name_allocated);
+}
+
+static void __dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
+{
+	if (dso__short_name_allocated(dso))
+		free((char *)dso__short_name(dso));
+
+	RC_CHK_ACCESS(dso)->short_name		  = name;
+	RC_CHK_ACCESS(dso)->short_name_len	  = strlen(name);
+	dso__set_short_name_allocated(dso, name_allocated);
+}
+
+void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
+{
+	struct dsos *dsos = dso__dsos(dso);
+
+	if (name == NULL)
+		return;
+
+	if (dsos) {
+		/*
+		 * Need to avoid re-sorting the dsos breaking by non-atomically
+		 * renaming the dso.
+		 */
+		down_write(&dsos->lock);
+		__dso__set_short_name(dso, name, name_allocated);
+		dsos->sorted = false;
+		up_write(&dsos->lock);
+	} else {
+		__dso__set_short_name(dso, name, name_allocated);
+	}
+}
+
+int dso__name_len(const struct dso *dso)
+{
+	if (!dso)
+		return strlen("[unknown]");
+	if (verbose > 0)
+		return dso__long_name_len(dso);
+
+	return dso__short_name_len(dso);
+}
+
+bool dso__loaded(const struct dso *dso)
+{
+	return RC_CHK_ACCESS(dso)->loaded;
+}
+
+bool dso__sorted_by_name(const struct dso *dso)
+{
+	return RC_CHK_ACCESS(dso)->sorted_by_name;
+}
+
+void dso__set_sorted_by_name(struct dso *dso)
+{
+	RC_CHK_ACCESS(dso)->sorted_by_name = true;
+}
+
+struct dso *dso__new_id(const char *name, const struct dso_id *id)
+{
+	RC_STRUCT(dso) *dso = zalloc(sizeof(*dso) + strlen(name) + 1);
+	struct dso *res;
+	struct dso_data *data;
+
+	if (!dso)
+		return NULL;
+
+	if (ADD_RC_CHK(res, dso)) {
+		strcpy(dso->name, name);
+		if (id)
+			dso->id = *id;
+		dso__set_long_name_id(res, dso->name, false);
+		dso__set_short_name(res, dso->name, false);
+		dso->symbols = RB_ROOT_CACHED;
+		dso->symbol_names = NULL;
+		dso->symbol_names_len = 0;
+		dso->inlined_nodes = RB_ROOT_CACHED;
+		dso->srclines = RB_ROOT_CACHED;
+		dso->data_types = RB_ROOT;
+		dso->global_vars = RB_ROOT;
+		dso->data.fd = -1;
+		dso->data.status = DSO_DATA_STATUS_UNKNOWN;
+		dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND;
+		dso->binary_type = DSO_BINARY_TYPE__NOT_FOUND;
+		dso->is_64_bit = (sizeof(void *) == 8);
+		dso->loaded = 0;
+		dso->rel = 0;
+		dso->sorted_by_name = 0;
+		dso->has_srcline = 1;
+		dso->a2l_fails = 1;
+		dso->kernel = DSO_SPACE__USER;
+		dso->is_kmod = 0;
+		dso->needs_swap = DSO_SWAP__UNSET;
+		dso->comp = COMP_ID__NONE;
+		mutex_init(&dso->lock);
+		refcount_set(&dso->refcnt, 1);
+		data = &dso->data;
+		data->cache = RB_ROOT;
+		data->fd = -1;
+		data->status = DSO_DATA_STATUS_UNKNOWN;
+		INIT_LIST_HEAD(&data->open_entry);
+#ifdef REFCNT_CHECKING
+		data->dso = NULL; /* Set when on the open_entry list. */
+#endif
+	}
+	return res;
+}
+
+struct dso *dso__new(const char *name)
+{
+	return dso__new_id(name, NULL);
+}
+
+void dso__delete(struct dso *dso)
+{
+	if (dso__dsos(dso))
+		pr_err("DSO %s is still in rbtree when being deleted!\n", dso__long_name(dso));
+
+	/* free inlines first, as they reference symbols */
+	inlines__tree_delete(&RC_CHK_ACCESS(dso)->inlined_nodes);
+	srcline__tree_delete(&RC_CHK_ACCESS(dso)->srclines);
+	symbols__delete(&RC_CHK_ACCESS(dso)->symbols);
+	RC_CHK_ACCESS(dso)->symbol_names_len = 0;
+	zfree(&RC_CHK_ACCESS(dso)->symbol_names);
+	annotated_data_type__tree_delete(dso__data_types(dso));
+	global_var_type__tree_delete(dso__global_vars(dso));
+
+	if (RC_CHK_ACCESS(dso)->short_name_allocated) {
+		zfree((char **)&RC_CHK_ACCESS(dso)->short_name);
+		RC_CHK_ACCESS(dso)->short_name_allocated = false;
+	}
+
+	if (RC_CHK_ACCESS(dso)->long_name_allocated) {
+		zfree((char **)&RC_CHK_ACCESS(dso)->long_name);
+		RC_CHK_ACCESS(dso)->long_name_allocated = false;
+	}
+
+	dso__data_close(dso);
+	auxtrace_cache__free(RC_CHK_ACCESS(dso)->auxtrace_cache);
+	dso_cache__free(dso);
+	dso__free_a2l(dso);
+	dso__free_libdw(dso);
+	dso__free_symsrc_filename(dso);
+	nsinfo__zput(RC_CHK_ACCESS(dso)->nsinfo);
+	mutex_destroy(dso__lock(dso));
+	RC_CHK_FREE(dso);
+}
+
+struct dso *dso__get(struct dso *dso)
+{
+	struct dso *result;
+
+	if (RC_CHK_GET(result, dso))
+		refcount_inc(&RC_CHK_ACCESS(dso)->refcnt);
+
+	return result;
+}
+
+void dso__put(struct dso *dso)
+{
+#ifdef REFCNT_CHECKING
+	if (dso && dso__data(dso) && refcount_read(&RC_CHK_ACCESS(dso)->refcnt) == 2)
+		dso__data_close(dso);
+#endif
+	if (dso && refcount_dec_and_test(&RC_CHK_ACCESS(dso)->refcnt))
+		dso__delete(dso);
+	else
+		RC_CHK_PUT(dso);
+}
+
+int dso__swap_init(struct dso *dso, unsigned char eidata)
+{
+	enum dso_swap_type type = dso_swap_type__from_elf_data(eidata);
+
+	dso__set_needs_swap(dso, type);
+	if (type == DSO_SWAP__UNSET) {
+		pr_err("unrecognized DSO data encoding %d\n", eidata);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+void dso__set_build_id(struct dso *dso, const struct build_id *bid)
+{
+	dso__id(dso)->build_id = *bid;
+}
+
+bool dso__build_id_equal(const struct dso *dso, const struct build_id *bid)
+{
+	const struct build_id *dso_bid = dso__bid(dso);
+
+	if (dso_bid->size > bid->size && dso_bid->size == BUILD_ID_SIZE) {
+		/*
+		 * For the backward compatibility, it allows a build-id has
+		 * trailing zeros.
+		 */
+		return !memcmp(dso_bid->data, bid->data, bid->size) &&
+			!memchr_inv(&dso_bid->data[bid->size], 0,
+				    dso_bid->size - bid->size);
+	}
+
+	return dso_bid->size == bid->size &&
+	       memcmp(dso_bid->data, bid->data, dso_bid->size) == 0;
+}
+
+void dso__read_running_kernel_build_id(struct dso *dso, struct machine *machine)
+{
+	char path[PATH_MAX];
+	struct build_id bid = { .size = 0, };
+
+	if (machine__is_default_guest(machine))
+		return;
+	snprintf(path, sizeof(path), "%s/sys/kernel/notes", machine->root_dir);
+	sysfs__read_build_id(path, &bid);
+	dso__set_build_id(dso, &bid);
+}
+
+int dso__kernel_module_get_build_id(struct dso *dso,
+				    const char *root_dir)
+{
+	char filename[PATH_MAX];
+	struct build_id bid = { .size = 0, };
+	/*
+	 * kernel module short names are of the form "[module]" and
+	 * we need just "module" here.
+	 */
+	const char *name = dso__short_name(dso) + 1;
+
+	snprintf(filename, sizeof(filename),
+		 "%s/sys/module/%.*s/notes/.note.gnu.build-id",
+		 root_dir, (int)strlen(name) - 1, name);
+
+	sysfs__read_build_id(filename, &bid);
+	dso__set_build_id(dso, &bid);
+	return 0;
+}
+
+static size_t dso__fprintf_buildid(struct dso *dso, FILE *fp)
+{
+	char sbuild_id[SBUILD_ID_SIZE];
+
+	build_id__snprintf(dso__bid(dso), sbuild_id, sizeof(sbuild_id));
+	return fprintf(fp, "%s", sbuild_id);
+}
+
+size_t dso__fprintf(struct dso *dso, FILE *fp)
+{
+	struct rb_node *nd;
+	size_t ret = fprintf(fp, "dso: %s (", dso__short_name(dso));
+
+	if (dso__short_name(dso) != dso__long_name(dso))
+		ret += fprintf(fp, "%s, ", dso__long_name(dso));
+	ret += fprintf(fp, "%sloaded, ", dso__loaded(dso) ? "" : "NOT ");
+	ret += dso__fprintf_buildid(dso, fp);
+	ret += fprintf(fp, ")\n");
+	for (nd = rb_first_cached(dso__symbols(dso)); nd; nd = rb_next(nd)) {
+		struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
+		ret += symbol__fprintf(pos, fp);
+	}
+
+	return ret;
+}
+
+enum dso_type dso__type(struct dso *dso, struct machine *machine)
+{
+	int fd = -1;
+	enum dso_type type = DSO__TYPE_UNKNOWN;
+
+	if (dso__data_get_fd(dso, machine, &fd)) {
+		type = dso__type_fd(fd);
+		dso__data_put_fd(dso);
+	}
+
+	return type;
+}
+
+int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
+{
+	int idx, errnum = *dso__load_errno(dso);
+	/*
+	 * This must have a same ordering as the enum dso_load_errno.
+	 */
+	static const char *dso_load__error_str[] = {
+	"Internal tools/perf/ library error",
+	"Invalid ELF file",
+	"Can not read build id",
+	"Mismatching build id",
+	"Decompression failure",
+	};
+
+	BUG_ON(buflen == 0);
+
+	if (errnum >= 0) {
+		errno = errnum;
+		scnprintf(buf, buflen, "%m");
+
+		return 0;
+	}
+
+	if (errnum <  __DSO_LOAD_ERRNO__START || errnum >= __DSO_LOAD_ERRNO__END)
+		return -1;
+
+	idx = errnum - __DSO_LOAD_ERRNO__START;
+	scnprintf(buf, buflen, "%s", dso_load__error_str[idx]);
+	return 0;
+}
+
+bool perf_pid_map_tid(const char *dso_name, int *tid)
+{
+	return sscanf(dso_name, "/tmp/perf-%d.map", tid) == 1;
+}
+
+bool is_perf_pid_map_name(const char *dso_name)
+{
+	int tid;
+
+	return perf_pid_map_tid(dso_name, &tid);
+}
+
+struct find_file_offset_data {
+	u64 ip;
+	u64 offset;
+};
+
+/* This will be called for each PHDR in an ELF binary */
+static int find_file_offset(u64 start, u64 len, u64 pgoff, void *arg)
+{
+	struct find_file_offset_data *data = arg;
+
+	if (start <= data->ip && data->ip < start + len) {
+		data->offset = pgoff + data->ip - start;
+		return 1;
+	}
+	return 0;
+}
+
+static const u8 *__dso__read_symbol(struct dso *dso, const char *symfs_filename,
+				    u64 start, size_t len,
+				    u8 **out_buf, u64 *out_buf_len, bool *is_64bit)
+{
+	struct nscookie nsc;
+	int fd;
+	ssize_t count;
+	struct find_file_offset_data data = {
+		.ip = start,
+	};
+	u8 *code_buf = NULL;
+	int saved_errno;
+
+	nsinfo__mountns_enter(dso__nsinfo(dso), &nsc);
+	fd = open(symfs_filename, O_RDONLY | O_CLOEXEC);
+	saved_errno = errno;
+	nsinfo__mountns_exit(&nsc);
+	if (fd < 0) {
+		errno = saved_errno;
+		return NULL;
+	}
+	if (file__read_maps(fd, /*exe=*/true, find_file_offset, &data, is_64bit) <= 0) {
+		close(fd);
+		errno = ENOENT;
+		return NULL;
+	}
+	code_buf = malloc(len);
+	if (code_buf == NULL) {
+		close(fd);
+		errno = ENOMEM;
+		return NULL;
+	}
+	count = pread(fd, code_buf, len, data.offset);
+	saved_errno = errno;
+	close(fd);
+	if ((u64)count != len) {
+		free(code_buf);
+		errno = saved_errno;
+		return NULL;
+	}
+	*out_buf = code_buf;
+	*out_buf_len = len;
+	return code_buf;
+}
+
+/*
+ * Read a symbol into memory for disassembly by a library like capstone of
+ * libLLVM. If memory is allocated out_buf holds it.
+ */
+const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename,
+			   const struct map *map, const struct symbol *sym,
+			   u8 **out_buf, u64 *out_buf_len, bool *is_64bit)
+{
+	u64 start = map__rip_2objdump(map, sym->start);
+	u64 end = map__rip_2objdump(map, sym->end);
+	size_t len = end - start;
+
+	*out_buf = NULL;
+	*out_buf_len = 0;
+	*is_64bit = false;
+
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_IMAGE) {
+		/*
+		 * Note, there is fallback BPF image disassembly in the objdump
+		 * version but it currently does nothing.
+		 */
+		errno = EOPNOTSUPP;
+		return NULL;
+	}
+	if (dso__binary_type(dso) == DSO_BINARY_TYPE__BPF_PROG_INFO) {
+#ifdef HAVE_LIBBPF_SUPPORT
+		struct bpf_prog_info_node *info_node;
+		struct perf_bpil *info_linear;
+
+		*is_64bit = sizeof(void *) == sizeof(u64);
+		info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env,
+							 dso__bpf_prog(dso)->id);
+		if (!info_node) {
+			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+			return NULL;
+		}
+		info_linear = info_node->info_linear;
+		if (!(info_linear->arrays & (1UL << PERF_BPIL_JITED_INSNS))) {
+			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+			return NULL;
+		}
+		if (len > info_linear->info.jited_prog_len) {
+			pr_debug("BPF symbol length %zu exceeds jited_prog_len %u\n",
+				 len, info_linear->info.jited_prog_len);
+			errno = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+			return NULL;
+		}
+		*out_buf_len = len;
+		return (const u8 *)(uintptr_t)(info_linear->info.jited_prog_insns);
+#else
+		pr_debug("No BPF program disassembly support\n");
+		errno = EOPNOTSUPP;
+		return NULL;
+#endif
+	}
+	return __dso__read_symbol(dso, symfs_filename, start, len,
+				  out_buf, out_buf_len, is_64bit);
+}
+
+struct debuginfo *dso__debuginfo(struct dso *dso)
+{
+	char *name;
+	bool decomp = false;
+	struct debuginfo *dinfo = NULL;
+
+	mutex_lock(dso__lock(dso));
+
+	name = dso__get_filename(dso, "", &decomp);
+	if (name)
+		dinfo = debuginfo__new(name);
+
+	if (decomp)
+		unlink(name);
+
+	mutex_unlock(dso__lock(dso));
+	free(name);
+	return dinfo;
+}