Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

9 files changed, 940 insertions, 0 deletions

diff --git a/arch/mips/vdso/.gitignore b/arch/mips/vdso/.gitignore
new file mode 100644
index 000000000..1f43f6dd8
--- /dev/null
+++ b/arch/mips/vdso/.gitignore
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+*.so*
+vdso-*image.c
+genvdso
+vdso*.lds
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
new file mode 100644
index 000000000..00d3ba2c4
--- /dev/null
+++ b/arch/mips/vdso/Makefile
@@ -0,0 +1,197 @@
+# SPDX-License-Identifier: GPL-2.0
+# Objects to go into the VDSO.
+
+# Include the generic Makefile to check the built vdso.
+include $(srctree)/lib/vdso/Makefile.include
+
+obj-vdso-y := elf.o sigreturn.o
+
+# Common compiler flags between ABIs.
+ccflags-vdso := \
+	$(filter -I%,$(KBUILD_CFLAGS)) \
+	$(filter -E%,$(KBUILD_CFLAGS)) \
+	$(filter -mmicromips,$(KBUILD_CFLAGS)) \
+	$(filter -march=%,$(KBUILD_CFLAGS)) \
+	$(filter -m%-float,$(KBUILD_CFLAGS)) \
+	$(filter -mno-loongson-%,$(KBUILD_CFLAGS)) \
+	$(CLANG_FLAGS) \
+	-D__VDSO__
+
+ifndef CONFIG_64BIT
+ccflags-vdso += -DBUILD_VDSO32
+endif
+
+#
+# The -fno-jump-tables flag only prevents the compiler from generating
+# jump tables but does not prevent the compiler from emitting absolute
+# offsets.
+cflags-vdso := $(ccflags-vdso) \
+	$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
+	$(filter -std=%,$(KBUILD_CFLAGS)) \
+	-O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
+	-mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \
+	-fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
+	$(call cc-option, -fno-asynchronous-unwind-tables)
+aflags-vdso := $(ccflags-vdso) \
+	-D__ASSEMBLY__ -Wa,-gdwarf-2
+
+ifneq ($(c-gettimeofday-y),)
+obj-vdso-y += vgettimeofday.o
+CFLAGS_vgettimeofday.o = -include $(c-gettimeofday-y)
+
+# config-n32-o32-env.c prepares the environment to build a 32bit vDSO
+# library on a 64bit kernel.
+# Note: Needs to be included before than the generic library.
+CFLAGS_vgettimeofday-o32.o = -include $(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
+CFLAGS_vgettimeofday-n32.o = -include $(src)/config-n32-o32-env.c -include $(c-gettimeofday-y)
+endif
+
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE)
+
+# VDSO linker flags.
+ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
+	$(filter -E%,$(KBUILD_CFLAGS)) -shared \
+	-G 0 --eh-frame-hdr --hash-style=sysv --build-id=sha1 -T
+
+CFLAGS_REMOVE_vdso.o = $(CC_FLAGS_FTRACE)
+
+# Check that we don't have PIC 'jalr t9' calls left
+quiet_cmd_vdso_mips_check = VDSOCHK $@
+      cmd_vdso_mips_check = if $(OBJDUMP) --disassemble $@ | grep -E -h "jalr.*t9" > /dev/null; \
+		       then (echo >&2 "$@: PIC 'jalr t9' calls are not supported"; \
+			     rm -f $@; /bin/false); fi
+
+#
+# Shared build commands.
+#
+
+quiet_cmd_vdsold_and_vdso_check = LD      $@
+      cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check); $(cmd_vdso_mips_check)
+
+quiet_cmd_vdsoas_o_S = AS      $@
+      cmd_vdsoas_o_S = $(CC) $(a_flags) -c -o $@ $<
+
+# Strip rule for the raw .so files
+$(obj)/%.so.raw: OBJCOPYFLAGS := -S
+$(obj)/%.so.raw: $(obj)/%.so.dbg.raw FORCE
+	$(call if_changed,objcopy)
+
+hostprogs := genvdso
+
+quiet_cmd_genvdso = GENVDSO $@
+define cmd_genvdso
+	$(foreach file,$(filter %.raw,$^),cp $(file) $(file:%.raw=%) &&) \
+	$(obj)/genvdso $(<:%.raw=%) $(<:%.dbg.raw=%) $@ $(VDSO_NAME)
+endef
+
+#
+# Build native VDSO.
+#
+
+native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
+
+targets += $(obj-vdso-y)
+targets += vdso.lds
+targets += vdso.so.dbg.raw vdso.so.raw
+targets += vdso.so.dbg vdso.so
+targets += vdso-image.c
+
+obj-vdso := $(obj-vdso-y:%.o=$(obj)/%.o)
+
+$(obj-vdso): KBUILD_CFLAGS := $(cflags-vdso) $(native-abi)
+$(obj-vdso): KBUILD_AFLAGS := $(aflags-vdso) $(native-abi)
+
+$(obj)/vdso.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) $(native-abi)
+
+$(obj)/vdso.so.dbg.raw: $(obj)/vdso.lds $(obj-vdso) FORCE
+	$(call if_changed,vdsold_and_vdso_check)
+
+$(obj)/vdso-image.c: $(obj)/vdso.so.dbg.raw $(obj)/vdso.so.raw \
+                     $(obj)/genvdso FORCE
+	$(call if_changed,genvdso)
+
+obj-y += vdso-image.o
+
+#
+# Build O32 VDSO.
+#
+
+# Define these outside the ifdef to ensure they are picked up by clean.
+targets += $(obj-vdso-y:%.o=%-o32.o)
+targets += vdso-o32.lds
+targets += vdso-o32.so.dbg.raw vdso-o32.so.raw
+targets += vdso-o32.so.dbg vdso-o32.so
+targets += vdso-o32-image.c
+
+ifdef CONFIG_MIPS32_O32
+
+obj-vdso-o32 := $(obj-vdso-y:%.o=$(obj)/%-o32.o)
+
+$(obj-vdso-o32): KBUILD_CFLAGS := $(cflags-vdso) -mabi=32
+$(obj-vdso-o32): KBUILD_AFLAGS := $(aflags-vdso) -mabi=32
+
+$(obj)/%-o32.o: $(src)/%.S FORCE
+	$(call if_changed_dep,vdsoas_o_S)
+
+$(obj)/%-o32.o: $(src)/%.c FORCE
+	$(call cmd,force_checksrc)
+	$(call if_changed_rule,cc_o_c)
+
+$(obj)/vdso-o32.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) -mabi=32
+$(obj)/vdso-o32.lds: $(src)/vdso.lds.S FORCE
+	$(call if_changed_dep,cpp_lds_S)
+
+$(obj)/vdso-o32.so.dbg.raw: $(obj)/vdso-o32.lds $(obj-vdso-o32) FORCE
+	$(call if_changed,vdsold_and_vdso_check)
+
+$(obj)/vdso-o32-image.c: VDSO_NAME := o32
+$(obj)/vdso-o32-image.c: $(obj)/vdso-o32.so.dbg.raw $(obj)/vdso-o32.so.raw \
+                         $(obj)/genvdso FORCE
+	$(call if_changed,genvdso)
+
+obj-y += vdso-o32-image.o
+
+endif
+
+#
+# Build N32 VDSO.
+#
+
+targets += $(obj-vdso-y:%.o=%-n32.o)
+targets += vdso-n32.lds
+targets += vdso-n32.so.dbg.raw vdso-n32.so.raw
+targets += vdso-n32.so.dbg vdso-n32.so
+targets += vdso-n32-image.c
+
+ifdef CONFIG_MIPS32_N32
+
+obj-vdso-n32 := $(obj-vdso-y:%.o=$(obj)/%-n32.o)
+
+$(obj-vdso-n32): KBUILD_CFLAGS := $(cflags-vdso) -mabi=n32
+$(obj-vdso-n32): KBUILD_AFLAGS := $(aflags-vdso) -mabi=n32
+
+$(obj)/%-n32.o: $(src)/%.S FORCE
+	$(call if_changed_dep,vdsoas_o_S)
+
+$(obj)/%-n32.o: $(src)/%.c FORCE
+	$(call cmd,force_checksrc)
+	$(call if_changed_rule,cc_o_c)
+
+$(obj)/vdso-n32.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) -mabi=n32
+$(obj)/vdso-n32.lds: $(src)/vdso.lds.S FORCE
+	$(call if_changed_dep,cpp_lds_S)
+
+$(obj)/vdso-n32.so.dbg.raw: $(obj)/vdso-n32.lds $(obj-vdso-n32) FORCE
+	$(call if_changed,vdsold_and_vdso_check)
+
+$(obj)/vdso-n32-image.c: VDSO_NAME := n32
+$(obj)/vdso-n32-image.c: $(obj)/vdso-n32.so.dbg.raw $(obj)/vdso-n32.so.raw \
+                         $(obj)/genvdso FORCE
+	$(call if_changed,genvdso)
+
+obj-y += vdso-n32-image.o
+
+endif
+
+# FIXME: Need install rule for debug.
+# Needs to deal with dependency for generation of dbg by cmd_genvdso...
diff --git a/arch/mips/vdso/config-n32-o32-env.c b/arch/mips/vdso/config-n32-o32-env.c
new file mode 100644
index 000000000..0011a632a
--- /dev/null
+++ b/arch/mips/vdso/config-n32-o32-env.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Configuration file for O32 and N32 binaries.
+ * Note: To be included before lib/vdso/gettimeofday.c
+ */
+#if defined(CONFIG_MIPS32_O32) || defined(CONFIG_MIPS32_N32)
+/*
+ * In case of a 32 bit VDSO for a 64 bit kernel fake a 32 bit kernel
+ * configuration.
+ */
+#undef CONFIG_64BIT
+
+#define BUILD_VDSO32
+#define CONFIG_32BIT 1
+#define CONFIG_GENERIC_ATOMIC64 1
+#define BUILD_VDSO32_64
+
+#endif
+
diff --git a/arch/mips/vdso/elf.S b/arch/mips/vdso/elf.S
new file mode 100644
index 000000000..821fcffe7
--- /dev/null
+++ b/arch/mips/vdso/elf.S
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+#include <asm/vdso/vdso.h>
+
+#include <asm/isa-rev.h>
+
+#include <linux/build-salt.h>
+#include <linux/elfnote.h>
+#include <linux/version.h>
+
+ELFNOTE_START(Linux, 0, "a")
+	.long LINUX_VERSION_CODE
+ELFNOTE_END
+
+BUILD_SALT
+
+/*
+ * The .MIPS.abiflags section must be defined with the FP ABI flags set
+ * to 'any' to be able to link with both old and new libraries.
+ * Newer toolchains are capable of automatically generating this, but we want
+ * to work with older toolchains as well. Therefore, we define the contents of
+ * this section here (under different names), and then genvdso will patch
+ * it to have the correct name and type.
+ *
+ * We base the .MIPS.abiflags section on preprocessor definitions rather than
+ * CONFIG_* because we need to match the particular ABI we are building the
+ * VDSO for.
+ *
+ * See https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking
+ * for the .MIPS.abiflags section description.
+ */
+
+	.section .mips_abiflags, "a"
+	.align 3
+__mips_abiflags:
+	.hword	0		/* version */
+	.byte	__mips		/* isa_level */
+
+	/* isa_rev */
+	.byte	MIPS_ISA_REV
+
+	/* gpr_size */
+#ifdef __mips64
+	.byte	2		/* AFL_REG_64 */
+#else
+	.byte	1		/* AFL_REG_32 */
+#endif
+
+	/* cpr1_size */
+#if (MIPS_ISA_REV >= 6) || defined(__mips64)
+	.byte	2		/* AFL_REG_64 */
+#else
+	.byte	1		/* AFL_REG_32 */
+#endif
+
+	.byte	0		/* cpr2_size (AFL_REG_NONE) */
+	.byte	0		/* fp_abi (Val_GNU_MIPS_ABI_FP_ANY) */
+	.word	0		/* isa_ext */
+	.word	0		/* ases */
+	.word	0		/* flags1 */
+	.word	0		/* flags2 */
diff --git a/arch/mips/vdso/genvdso.c b/arch/mips/vdso/genvdso.c
new file mode 100644
index 000000000..d47412ea6
--- /dev/null
+++ b/arch/mips/vdso/genvdso.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+/*
+ * This tool is used to generate the real VDSO images from the raw image. It
+ * first patches up the MIPS ABI flags and GNU attributes sections defined in
+ * elf.S to have the correct name and type. It then generates a C source file
+ * to be compiled into the kernel containing the VDSO image data and a
+ * mips_vdso_image struct for it, including symbol offsets extracted from the
+ * image.
+ *
+ * We need to be passed both a stripped and unstripped VDSO image. The stripped
+ * image is compiled into the kernel, but we must also patch up the unstripped
+ * image's ABI flags sections so that it can be installed and used for
+ * debugging.
+ */
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <byteswap.h>
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Define these in case the system elf.h is not new enough to have them. */
+#ifndef SHT_GNU_ATTRIBUTES
+# define SHT_GNU_ATTRIBUTES	0x6ffffff5
+#endif
+#ifndef SHT_MIPS_ABIFLAGS
+# define SHT_MIPS_ABIFLAGS	0x7000002a
+#endif
+
+enum {
+	ABI_O32 = (1 << 0),
+	ABI_N32 = (1 << 1),
+	ABI_N64 = (1 << 2),
+
+	ABI_ALL = ABI_O32 | ABI_N32 | ABI_N64,
+};
+
+/* Symbols the kernel requires offsets for. */
+static struct {
+	const char *name;
+	const char *offset_name;
+	unsigned int abis;
+} vdso_symbols[] = {
+	{ "__vdso_sigreturn", "off_sigreturn", ABI_O32 },
+	{ "__vdso_rt_sigreturn", "off_rt_sigreturn", ABI_ALL },
+	{}
+};
+
+static const char *program_name;
+static const char *vdso_name;
+static unsigned char elf_class;
+static unsigned int elf_abi;
+static bool need_swap;
+static FILE *out_file;
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define HOST_ORDER		ELFDATA2LSB
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define HOST_ORDER		ELFDATA2MSB
+#endif
+
+#define BUILD_SWAP(bits)						\
+	static uint##bits##_t swap_uint##bits(uint##bits##_t val)	\
+	{								\
+		return need_swap ? bswap_##bits(val) : val;		\
+	}
+
+BUILD_SWAP(16)
+BUILD_SWAP(32)
+BUILD_SWAP(64)
+
+#define __FUNC(name, bits) name##bits
+#define _FUNC(name, bits) __FUNC(name, bits)
+#define FUNC(name) _FUNC(name, ELF_BITS)
+
+#define __ELF(x, bits) Elf##bits##_##x
+#define _ELF(x, bits) __ELF(x, bits)
+#define ELF(x) _ELF(x, ELF_BITS)
+
+/*
+ * Include genvdso.h twice with ELF_BITS defined differently to get functions
+ * for both ELF32 and ELF64.
+ */
+
+#define ELF_BITS 64
+#include "genvdso.h"
+#undef ELF_BITS
+
+#define ELF_BITS 32
+#include "genvdso.h"
+#undef ELF_BITS
+
+static void *map_vdso(const char *path, size_t *_size)
+{
+	int fd;
+	struct stat stat;
+	void *addr;
+	const Elf32_Ehdr *ehdr;
+
+	fd = open(path, O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "%s: Failed to open '%s': %s\n", program_name,
+			path, strerror(errno));
+		return NULL;
+	}
+
+	if (fstat(fd, &stat) != 0) {
+		fprintf(stderr, "%s: Failed to stat '%s': %s\n", program_name,
+			path, strerror(errno));
+		close(fd);
+		return NULL;
+	}
+
+	addr = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
+		    0);
+	if (addr == MAP_FAILED) {
+		fprintf(stderr, "%s: Failed to map '%s': %s\n", program_name,
+			path, strerror(errno));
+		close(fd);
+		return NULL;
+	}
+
+	/* ELF32/64 header formats are the same for the bits we're checking. */
+	ehdr = addr;
+
+	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) {
+		fprintf(stderr, "%s: '%s' is not an ELF file\n", program_name,
+			path);
+		close(fd);
+		return NULL;
+	}
+
+	elf_class = ehdr->e_ident[EI_CLASS];
+	switch (elf_class) {
+	case ELFCLASS32:
+	case ELFCLASS64:
+		break;
+	default:
+		fprintf(stderr, "%s: '%s' has invalid ELF class\n",
+			program_name, path);
+		close(fd);
+		return NULL;
+	}
+
+	switch (ehdr->e_ident[EI_DATA]) {
+	case ELFDATA2LSB:
+	case ELFDATA2MSB:
+		need_swap = ehdr->e_ident[EI_DATA] != HOST_ORDER;
+		break;
+	default:
+		fprintf(stderr, "%s: '%s' has invalid ELF data order\n",
+			program_name, path);
+		close(fd);
+		return NULL;
+	}
+
+	if (swap_uint16(ehdr->e_machine) != EM_MIPS) {
+		fprintf(stderr,
+			"%s: '%s' has invalid ELF machine (expected EM_MIPS)\n",
+			program_name, path);
+		close(fd);
+		return NULL;
+	} else if (swap_uint16(ehdr->e_type) != ET_DYN) {
+		fprintf(stderr,
+			"%s: '%s' has invalid ELF type (expected ET_DYN)\n",
+			program_name, path);
+		close(fd);
+		return NULL;
+	}
+
+	*_size = stat.st_size;
+	close(fd);
+	return addr;
+}
+
+static bool patch_vdso(const char *path, void *vdso)
+{
+	if (elf_class == ELFCLASS64)
+		return patch_vdso64(path, vdso);
+	else
+		return patch_vdso32(path, vdso);
+}
+
+static bool get_symbols(const char *path, void *vdso)
+{
+	if (elf_class == ELFCLASS64)
+		return get_symbols64(path, vdso);
+	else
+		return get_symbols32(path, vdso);
+}
+
+int main(int argc, char **argv)
+{
+	const char *dbg_vdso_path, *vdso_path, *out_path;
+	void *dbg_vdso, *vdso;
+	size_t dbg_vdso_size, vdso_size, i;
+
+	program_name = argv[0];
+
+	if (argc < 4 || argc > 5) {
+		fprintf(stderr,
+			"Usage: %s <debug VDSO> <stripped VDSO> <output file> [<name>]\n",
+			program_name);
+		return EXIT_FAILURE;
+	}
+
+	dbg_vdso_path = argv[1];
+	vdso_path = argv[2];
+	out_path = argv[3];
+	vdso_name = (argc > 4) ? argv[4] : "";
+
+	dbg_vdso = map_vdso(dbg_vdso_path, &dbg_vdso_size);
+	if (!dbg_vdso)
+		return EXIT_FAILURE;
+
+	vdso = map_vdso(vdso_path, &vdso_size);
+	if (!vdso)
+		return EXIT_FAILURE;
+
+	/* Patch both the VDSOs' ABI flags sections. */
+	if (!patch_vdso(dbg_vdso_path, dbg_vdso))
+		return EXIT_FAILURE;
+	if (!patch_vdso(vdso_path, vdso))
+		return EXIT_FAILURE;
+
+	if (msync(dbg_vdso, dbg_vdso_size, MS_SYNC) != 0) {
+		fprintf(stderr, "%s: Failed to sync '%s': %s\n", program_name,
+			dbg_vdso_path, strerror(errno));
+		return EXIT_FAILURE;
+	} else if (msync(vdso, vdso_size, MS_SYNC) != 0) {
+		fprintf(stderr, "%s: Failed to sync '%s': %s\n", program_name,
+			vdso_path, strerror(errno));
+		return EXIT_FAILURE;
+	}
+
+	out_file = fopen(out_path, "w");
+	if (!out_file) {
+		fprintf(stderr, "%s: Failed to open '%s': %s\n", program_name,
+			out_path, strerror(errno));
+		return EXIT_FAILURE;
+	}
+
+	fprintf(out_file, "/* Automatically generated - do not edit */\n");
+	fprintf(out_file, "#include <linux/linkage.h>\n");
+	fprintf(out_file, "#include <linux/mm.h>\n");
+	fprintf(out_file, "#include <asm/vdso.h>\n");
+	fprintf(out_file, "static int vdso_mremap(\n");
+	fprintf(out_file, "	const struct vm_special_mapping *sm,\n");
+	fprintf(out_file, "	struct vm_area_struct *new_vma)\n");
+	fprintf(out_file, "{\n");
+	fprintf(out_file, "	current->mm->context.vdso =\n");
+	fprintf(out_file, "	(void *)(new_vma->vm_start);\n");
+	fprintf(out_file, "	return 0;\n");
+	fprintf(out_file, "}\n");
+
+	/* Write out the stripped VDSO data. */
+	fprintf(out_file,
+		"static unsigned char vdso_image_data[PAGE_ALIGN(%zu)] __page_aligned_data = {\n\t",
+		vdso_size);
+	for (i = 0; i < vdso_size; i++) {
+		if (!(i % 10))
+			fprintf(out_file, "\n\t");
+		fprintf(out_file, "0x%02x, ", ((unsigned char *)vdso)[i]);
+	}
+	fprintf(out_file, "\n};\n");
+
+	/* Preallocate a page array. */
+	fprintf(out_file,
+		"static struct page *vdso_pages[PAGE_ALIGN(%zu) / PAGE_SIZE];\n",
+		vdso_size);
+
+	fprintf(out_file, "struct mips_vdso_image vdso_image%s%s = {\n",
+		(vdso_name[0]) ? "_" : "", vdso_name);
+	fprintf(out_file, "\t.data = vdso_image_data,\n");
+	fprintf(out_file, "\t.size = PAGE_ALIGN(%zu),\n", vdso_size);
+	fprintf(out_file, "\t.mapping = {\n");
+	fprintf(out_file, "\t\t.name = \"[vdso]\",\n");
+	fprintf(out_file, "\t\t.pages = vdso_pages,\n");
+	fprintf(out_file, "\t\t.mremap = vdso_mremap,\n");
+	fprintf(out_file, "\t},\n");
+
+	/* Calculate and write symbol offsets to <output file> */
+	if (!get_symbols(dbg_vdso_path, dbg_vdso)) {
+		unlink(out_path);
+		fclose(out_file);
+		return EXIT_FAILURE;
+	}
+
+	fprintf(out_file, "};\n");
+	fclose(out_file);
+
+	return EXIT_SUCCESS;
+}
diff --git a/arch/mips/vdso/genvdso.h b/arch/mips/vdso/genvdso.h
new file mode 100644
index 000000000..9bfb87403
--- /dev/null
+++ b/arch/mips/vdso/genvdso.h
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+static inline bool FUNC(patch_vdso)(const char *path, void *vdso)
+{
+	const ELF(Ehdr) *ehdr = vdso;
+	void *shdrs;
+	ELF(Shdr) *shdr;
+	char *shstrtab, *name;
+	uint16_t sh_count, sh_entsize, i;
+
+	shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
+	sh_count = swap_uint16(ehdr->e_shnum);
+	sh_entsize = swap_uint16(ehdr->e_shentsize);
+
+	shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx));
+	shstrtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+
+	for (i = 0; i < sh_count; i++) {
+		shdr = shdrs + (i * sh_entsize);
+		name = shstrtab + swap_uint32(shdr->sh_name);
+
+		/*
+		 * Ensure there are no relocation sections - ld.so does not
+		 * relocate the VDSO so if there are relocations things will
+		 * break.
+		 */
+		switch (swap_uint32(shdr->sh_type)) {
+		case SHT_REL:
+		case SHT_RELA:
+			fprintf(stderr,
+				"%s: '%s' contains relocation sections\n",
+				program_name, path);
+			return false;
+		}
+
+		/* Check for existing sections. */
+		if (strcmp(name, ".MIPS.abiflags") == 0) {
+			fprintf(stderr,
+				"%s: '%s' already contains a '.MIPS.abiflags' section\n",
+				program_name, path);
+			return false;
+		}
+
+		if (strcmp(name, ".mips_abiflags") == 0) {
+			strcpy(name, ".MIPS.abiflags");
+			shdr->sh_type = swap_uint32(SHT_MIPS_ABIFLAGS);
+			shdr->sh_entsize = shdr->sh_size;
+		}
+	}
+
+	return true;
+}
+
+static inline bool FUNC(get_symbols)(const char *path, void *vdso)
+{
+	const ELF(Ehdr) *ehdr = vdso;
+	void *shdrs, *symtab;
+	ELF(Shdr) *shdr;
+	const ELF(Sym) *sym;
+	char *strtab, *name;
+	uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j;
+	uint64_t offset;
+	uint32_t flags;
+
+	shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff);
+	sh_count = swap_uint16(ehdr->e_shnum);
+	sh_entsize = swap_uint16(ehdr->e_shentsize);
+
+	for (i = 0; i < sh_count; i++) {
+		shdr = shdrs + (i * sh_entsize);
+
+		if (swap_uint32(shdr->sh_type) == SHT_SYMTAB)
+			break;
+	}
+
+	if (i == sh_count) {
+		fprintf(stderr, "%s: '%s' has no symbol table\n", program_name,
+			path);
+		return false;
+	}
+
+	/* Get flags */
+	flags = swap_uint32(ehdr->e_flags);
+	if (elf_class == ELFCLASS64)
+		elf_abi = ABI_N64;
+	else if (flags & EF_MIPS_ABI2)
+		elf_abi = ABI_N32;
+	else
+		elf_abi = ABI_O32;
+
+	/* Get symbol table. */
+	symtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+	st_entsize = FUNC(swap_uint)(shdr->sh_entsize);
+	st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize;
+
+	/* Get string table. */
+	shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize);
+	strtab = vdso + FUNC(swap_uint)(shdr->sh_offset);
+
+	/* Write offsets for symbols needed by the kernel. */
+	for (i = 0; vdso_symbols[i].name; i++) {
+		if (!(vdso_symbols[i].abis & elf_abi))
+			continue;
+
+		for (j = 0; j < st_count; j++) {
+			sym = symtab + (j * st_entsize);
+			name = strtab + swap_uint32(sym->st_name);
+
+			if (!strcmp(name, vdso_symbols[i].name)) {
+				offset = FUNC(swap_uint)(sym->st_value);
+
+				fprintf(out_file,
+					"\t.%s = 0x%" PRIx64 ",\n",
+					vdso_symbols[i].offset_name, offset);
+				break;
+			}
+		}
+
+		if (j == st_count) {
+			fprintf(stderr,
+				"%s: '%s' is missing required symbol '%s'\n",
+				program_name, path, vdso_symbols[i].name);
+			return false;
+		}
+	}
+
+	return true;
+}
diff --git a/arch/mips/vdso/sigreturn.S b/arch/mips/vdso/sigreturn.S
new file mode 100644
index 000000000..e5c0ab98a
--- /dev/null
+++ b/arch/mips/vdso/sigreturn.S
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+#include <asm/vdso/vdso.h>
+
+#include <uapi/asm/unistd.h>
+
+#include <asm/regdef.h>
+#include <asm/asm.h>
+
+	.section	.text
+	.cfi_sections	.debug_frame
+
+LEAF(__vdso_rt_sigreturn)
+	.cfi_signal_frame
+
+	li	v0, __NR_rt_sigreturn
+	syscall
+
+	END(__vdso_rt_sigreturn)
+
+#if _MIPS_SIM == _MIPS_SIM_ABI32
+
+LEAF(__vdso_sigreturn)
+	.cfi_signal_frame
+
+	li	v0, __NR_sigreturn
+	syscall
+
+	END(__vdso_sigreturn)
+
+#endif
diff --git a/arch/mips/vdso/vdso.lds.S b/arch/mips/vdso/vdso.lds.S
new file mode 100644
index 000000000..b11ee493c
--- /dev/null
+++ b/arch/mips/vdso/vdso.lds.S
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ */
+
+#include <asm/sgidefs.h>
+#include <asm/vdso/vdso.h>
+#include <vdso/datapage.h>
+
+#if _MIPS_SIM == _MIPS_SIM_ABI64
+OUTPUT_FORMAT("elf64-tradlittlemips", "elf64-tradbigmips", "elf64-tradlittlemips")
+#elif _MIPS_SIM == _MIPS_SIM_NABI32
+OUTPUT_FORMAT("elf32-ntradlittlemips", "elf32-ntradbigmips", "elf32-ntradlittlemips")
+#else
+OUTPUT_FORMAT("elf32-tradlittlemips", "elf32-tradbigmips", "elf32-tradlittlemips")
+#endif
+
+OUTPUT_ARCH(mips)
+
+SECTIONS
+{
+	VDSO_VVAR_SYMS
+
+	. = SIZEOF_HEADERS;
+
+	/*
+	 * In order to retain compatibility with older toolchains we provide the
+	 * ABI flags section ourself. Newer assemblers will automatically
+	 * generate .MIPS.abiflags sections so we discard such input sections,
+	 * and then manually define our own section here. genvdso will patch
+	 * this section to have the correct name/type.
+	 */
+	.mips_abiflags	: { *(.mips_abiflags) } 	:text :abiflags
+
+	.reginfo	: { *(.reginfo) }		:text :reginfo
+
+	.hash		: { *(.hash) }			:text
+	.gnu.hash	: { *(.gnu.hash) }
+	.dynsym		: { *(.dynsym) }
+	.dynstr		: { *(.dynstr) }
+	.gnu.version	: { *(.gnu.version) }
+	.gnu.version_d	: { *(.gnu.version_d) }
+	.gnu.version_r	: { *(.gnu.version_r) }
+
+	.note		: { *(.note.*) }		:text :note
+
+	.text		: { *(.text*) }			:text
+	PROVIDE (__etext = .);
+	PROVIDE (_etext = .);
+	PROVIDE (etext = .);
+
+	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text :eh_frame_hdr
+	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
+
+	.dynamic	: { *(.dynamic) }		:text :dynamic
+
+	.rodata		: { *(.rodata*) }		:text
+	.got		: { *(.got) }
+
+	_end = .;
+	PROVIDE(end = .);
+
+	/DISCARD/	: {
+		*(.MIPS.abiflags)
+		*(.gnu.attributes)
+		*(.note.GNU-stack)
+		*(.data .data.* .gnu.linkonce.d.* .sdata*)
+		*(.bss .sbss .dynbss .dynsbss)
+	}
+}
+
+PHDRS
+{
+	/*
+	 * Provide a PT_MIPS_ABIFLAGS header to assign the ABI flags section
+	 * to. We can specify the header type directly here so no modification
+	 * is needed later on.
+	 */
+	abiflags	0x70000003;
+
+	/*
+	 * The ABI flags header must exist directly after the PT_INTERP header,
+	 * so we must explicitly place the PT_MIPS_REGINFO header after it to
+	 * stop the linker putting one in at the start.
+	 */
+	reginfo		0x70000000;
+
+	text		PT_LOAD		FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
+	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
+	note		PT_NOTE		FLAGS(4);		/* PF_R */
+	eh_frame_hdr	PT_GNU_EH_FRAME;
+}
+
+VERSION
+{
+	LINUX_2.6 {
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+	global:
+#if _MIPS_SIM == _MIPS_SIM_ABI64 || defined(CONFIG_COMPAT_32BIT_TIME)
+		__vdso_clock_gettime;
+		__vdso_gettimeofday;
+		__vdso_clock_getres;
+#endif
+#if _MIPS_SIM != _MIPS_SIM_ABI64
+		__vdso_clock_gettime64;
+		__vdso_clock_getres_time64;
+#endif
+#endif
+	local: *;
+	};
+}
diff --git a/arch/mips/vdso/vgettimeofday.c b/arch/mips/vdso/vgettimeofday.c
new file mode 100644
index 000000000..a1fb06b89
--- /dev/null
+++ b/arch/mips/vdso/vgettimeofday.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MIPS64 and compat userspace implementations of gettimeofday()
+ * and similar.
+ *
+ * Copyright (C) 2015 Imagination Technologies
+ * Copyright (C) 2018 ARM Limited
+ *
+ */
+#include <linux/time.h>
+#include <linux/types.h>
+#include <vdso/gettime.h>
+
+#if _MIPS_SIM != _MIPS_SIM_ABI64
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+int __vdso_clock_gettime(clockid_t clock,
+			 struct old_timespec32 *ts)
+{
+	return __cvdso_clock_gettime32(clock, ts);
+}
+
+int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
+			struct timezone *tz)
+{
+	return __cvdso_gettimeofday(tv, tz);
+}
+
+int __vdso_clock_getres(clockid_t clock_id,
+			struct old_timespec32 *res)
+{
+	return __cvdso_clock_getres_time32(clock_id, res);
+}
+#endif /* CONFIG_COMPAT_32BIT_TIME */
+
+int __vdso_clock_gettime64(clockid_t clock,
+			   struct __kernel_timespec *ts)
+{
+	return __cvdso_clock_gettime(clock, ts);
+}
+
+int __vdso_clock_getres_time64(clockid_t clock, struct __kernel_timespec *ts)
+{
+	return __cvdso_clock_getres(clock, ts);
+}
+
+#else
+
+int __vdso_clock_gettime(clockid_t clock,
+			 struct __kernel_timespec *ts)
+{
+	return __cvdso_clock_gettime(clock, ts);
+}
+
+int __vdso_gettimeofday(struct __kernel_old_timeval *tv,
+			struct timezone *tz)
+{
+	return __cvdso_gettimeofday(tv, tz);
+}
+
+int __vdso_clock_getres(clockid_t clock_id,
+			struct __kernel_timespec *res)
+{
+	return __cvdso_clock_getres(clock_id, res);
+}
+
+#endif