xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

MIPS: Initial implementation of a VDSO

Browse Source 
Add an initial implementation of a proper (i.e. an ELF shared library)
VDSO. With this commit it does not export any symbols, it only replaces
the current signal return trampoline page. A later commit will add user
implementations of gettimeofday()/clock_gettime().

To support both new toolchains and old ones which don't generate ABI
flags section, we define its content manually and then use a tool
(genvdso) to patch up the section to have the correct name and type.
genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the
kernel, and generates a C file containing a "struct mips_vdso_image"
containing both the VDSO data and these offsets. This C file is
compiled into the kernel.

On 64-bit kernels we require a different VDSO for each supported ABI,
so we may build up to 3 different VDSOs. The VDSO to use is selected by
the mips_abi structure.

A kernel/user shared data page is created and mapped below the VDSO
image. This is currently empty, but will be used by the user time
function implementations which are added later.

[markos.chandras@imgtec.com:
- Add more comments
- Move abi detection in genvdso.h since it's the get_symbol function
that needs it.
- Add an R6 specific way to calculate the base address of VDSO in order
to avoid the branch instruction which affects performance.
- Do not patch .gnu.attributes since it's not needed for dynamic linking.
- Simplify Makefile a little bit.
- checkpatch fixes
- Restrict VDSO support for binutils < 2.25 for pre-R6
- Include atomic64.h for O32 variant on MIPS64]

Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11337/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Alex Smith
2015-10-21 09:54:38 +01:00
committed by Ralf Baechle
parent 22773aa9b9
commit ebb5e78cc6
19 changed files with 1113 additions and 123 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
arch/mips/vdso/.gitignore vendored Normal file
View File

@@ -0,0 +1,4 @@
*.so*
vdso-*image.c
genvdso
vdso*.lds

160
arch/mips/vdso/Makefile Normal file
View File

@@ -0,0 +1,160 @@
# Objects to go into the VDSO.
obj-vdso-y := elf.o gettimeofday.o sigreturn.o
# Common compiler flags between ABIs.
ccflags-vdso := \
$(filter -I%,$(KBUILD_CFLAGS)) \
$(filter -E%,$(KBUILD_CFLAGS)) \
$(filter -march=%,$(KBUILD_CFLAGS))
cflags-vdso := $(ccflags-vdso) \
$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
-O2 -g -fPIC -fno-common -fno-builtin -G 0 -DDISABLE_BRANCH_PROFILING \
$(call cc-option, -fno-stack-protector)
aflags-vdso := $(ccflags-vdso) \
$(filter -I%,$(KBUILD_CFLAGS)) \
$(filter -E%,$(KBUILD_CFLAGS)) \
-D__ASSEMBLY__ -Wa,-gdwarf-2
#
# For the pre-R6 code in arch/mips/vdso/vdso.h for locating
# the base address of VDSO, the linker will emit a R_MIPS_PC32
# relocation in binutils > 2.25 but it will fail with older versions
# because that relocation is not supported for that symbol. As a result
# of which we are forced to disable the VDSO symbols when building
# with < 2.25 binutils on pre-R6 kernels. For more references on why we
# can't use other methods to get the base address of VDSO please refer to
# the comments on that file.
#
ifndef CONFIG_CPU_MIPSR6
ifeq ($(call ld-ifversion, -gt, 22400000, y),)
$(warning MIPS VDSO requires binutils > 2.24)
obj-vdso-y := $(filter-out gettimeofday.o, $(obj-vdso-y))
ccflags-vdso += -DDISABLE_MIPS_VDSO
endif
endif
# VDSO linker flags.
VDSO_LDFLAGS := \
-Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 \
-nostdlib -shared \
$(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
$(call cc-ldoption, -Wl$(comma)--build-id)
GCOV_PROFILE := n
#
# Shared build commands.
#
quiet_cmd_vdsold = VDSO $@
cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \
-Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@
hostprogs-y := genvdso
quiet_cmd_genvdso = GENVDSO $@
define cmd_genvdso
cp $< $(<:%.dbg=%) && \
$(OBJCOPY) -S $< $(<:%.dbg=%) && \
$(obj)/genvdso $< $(<:%.dbg=%) $@ $(VDSO_NAME)
endef
#
# Build native VDSO.
#
native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
targets += $(obj-vdso-y)
targets += vdso.lds vdso.so.dbg vdso.so 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 := $(native-abi)
$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
$(call if_changed,vdsold)
$(obj)/vdso-image.c: $(obj)/vdso.so.dbg $(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 vdso-o32.so.dbg vdso-o32.so 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,as_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 := -mabi=32
$(obj)/vdso-o32.lds: $(src)/vdso.lds.S FORCE
$(call if_changed_dep,cpp_lds_S)
$(obj)/vdso-o32.so.dbg: $(obj)/vdso-o32.lds $(obj-vdso-o32) FORCE
$(call if_changed,vdsold)
$(obj)/vdso-o32-image.c: VDSO_NAME := o32
$(obj)/vdso-o32-image.c: $(obj)/vdso-o32.so.dbg $(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 vdso-n32.so.dbg vdso-n32.so 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,as_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 := -mabi=n32
$(obj)/vdso-n32.lds: $(src)/vdso.lds.S FORCE
$(call if_changed_dep,cpp_lds_S)
$(obj)/vdso-n32.so.dbg: $(obj)/vdso-n32.lds $(obj-vdso-n32) FORCE
$(call if_changed,vdsold)
$(obj)/vdso-n32-image.c: VDSO_NAME := n32
$(obj)/vdso-n32-image.c: $(obj)/vdso-n32.so.dbg $(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...

68
arch/mips/vdso/elf.S Normal file
View File

@@ -0,0 +1,68 @@
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include "vdso.h"
#include <linux/elfnote.h>
#include <linux/version.h>
ELFNOTE_START(Linux, 0, "a")
.long LINUX_VERSION_CODE
ELFNOTE_END
/*
* 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 */
#ifdef __mips_isa_rev
.byte __mips_isa_rev
#else
.byte 0
#endif
/* gpr_size */
#ifdef __mips64
.byte 2 /* AFL_REG_64 */
#else
.byte 1 /* AFL_REG_32 */
#endif
/* cpr1_size */
#if (defined(__mips_isa_rev) && __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 */

293
arch/mips/vdso/genvdso.c Normal file
View File

@@ -0,0 +1,293 @@
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
/*
* 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));
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));
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);
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);
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);
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);
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);
return NULL;
}
*_size = stat.st_size;
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");
/* Write out the stripped VDSO data. */
fprintf(out_file,
"static unsigned char vdso_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_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},\n");
/* Calculate and write symbol offsets to <output file> */
if (!get_symbols(dbg_vdso_path, dbg_vdso)) {
unlink(out_path);
return EXIT_FAILURE;
}
fprintf(out_file, "};\n");
return EXIT_SUCCESS;
}

187
arch/mips/vdso/genvdso.h Normal file
View File

@@ -0,0 +1,187 @@
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
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;
unsigned int local_gotno, symtabno, gotsym;
ELF(Dyn) *dyn = NULL;
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;
case SHT_DYNAMIC:
dyn = vdso + FUNC(swap_uint)(shdr->sh_offset);
break;
}
/* 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;
}
}
/*
* Ensure the GOT has no entries other than the standard 2, for the same
* reason we check that there's no relocation sections above.
* The standard two entries are:
* - Lazy resolver
* - Module pointer
*/
if (dyn) {
local_gotno = symtabno = gotsym = 0;
while (FUNC(swap_uint)(dyn->d_tag) != DT_NULL) {
switch (FUNC(swap_uint)(dyn->d_tag)) {
/*
* This member holds the number of local GOT entries.
*/
case DT_MIPS_LOCAL_GOTNO:
local_gotno = FUNC(swap_uint)(dyn->d_un.d_val);
break;
/*
* This member holds the number of entries in the
* .dynsym section.
*/
case DT_MIPS_SYMTABNO:
symtabno = FUNC(swap_uint)(dyn->d_un.d_val);
break;
/*
* This member holds the index of the first dynamic
* symbol table entry that corresponds to an entry in
* the GOT.
*/
case DT_MIPS_GOTSYM:
gotsym = FUNC(swap_uint)(dyn->d_un.d_val);
break;
}
dyn++;
}
if (local_gotno > 2 || symtabno - gotsym) {
fprintf(stderr,
"%s: '%s' contains unexpected GOT entries\n",
program_name, path);
return false;
}
}
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;
}

49
arch/mips/vdso/sigreturn.S Normal file
View File

@@ -0,0 +1,49 @@
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include "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_startproc
.frame sp, 0, ra
.mask 0x00000000, 0
.fmask 0x00000000, 0
.cfi_signal_frame
li v0, __NR_rt_sigreturn
syscall
.cfi_endproc
END(__vdso_rt_sigreturn)
#if _MIPS_SIM == _MIPS_SIM_ABI32
LEAF(__vdso_sigreturn)
.cfi_startproc
.frame sp, 0, ra
.mask 0x00000000, 0
.fmask 0x00000000, 0
.cfi_signal_frame
li v0, __NR_sigreturn
syscall
.cfi_endproc
END(__vdso_sigreturn)
#endif

80
arch/mips/vdso/vdso.h Normal file
View File

@@ -0,0 +1,80 @@
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <asm/sgidefs.h>
#if _MIPS_SIM != _MIPS_SIM_ABI64 && defined(CONFIG_64BIT)
/* Building 32-bit VDSO for the 64-bit kernel. Fake a 32-bit Kconfig. */
#undef CONFIG_64BIT
#define CONFIG_32BIT 1
#ifndef __ASSEMBLY__
#include <asm-generic/atomic64.h>
#endif
#endif
#ifndef __ASSEMBLY__
#include <asm/asm.h>
#include <asm/page.h>
#include <asm/vdso.h>
static inline unsigned long get_vdso_base(void)
{
unsigned long addr;
/*
* We can't use cpu_has_mips_r6 since it needs the cpu_data[]
* kernel symbol.
*/
#ifdef CONFIG_CPU_MIPSR6
/*
* lapc <symbol> is an alias to addiupc reg, <symbol> - .
*
* We can't use addiupc because there is no label-label
* support for the addiupc reloc
*/
__asm__("lapc %0, _start \n"
: "=r" (addr) : :);
#else
/*
* Get the base load address of the VDSO. We have to avoid generating
* relocations and references to the GOT because ld.so does not peform
* relocations on the VDSO. We use the current offset from the VDSO base
* and perform a PC-relative branch which gives the absolute address in
* ra, and take the difference. The assembler chokes on
* "li %0, _start - .", so embed the offset as a word and branch over
* it.
*
*/
__asm__(
" .set push \n"
" .set noreorder \n"
" bal 1f \n"
" nop \n"
" .word _start - . \n"
"1: lw %0, 0($31) \n"
" " STR(PTR_ADDU) " %0, $31, %0 \n"
" .set pop \n"
: "=r" (addr)
:
: "$31");
#endif /* CONFIG_CPU_MIPSR6 */
return addr;
}
static inline const union mips_vdso_data *get_vdso_data(void)
{
return (const union mips_vdso_data *)(get_vdso_base() - PAGE_SIZE);
}
#endif /* __ASSEMBLY__ */

100
arch/mips/vdso/vdso.lds.S Normal file
View File

@@ -0,0 +1,100 @@
/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <asm/sgidefs.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
{
PROVIDE(_start = .);
. = 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
_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 {
local: *;
};
}