Commit d59a1683 authored by David Daney's avatar David Daney Committed by H. Peter Anvin

scripts/sortextable: Handle relative entries, and other cleanups

x86 is now using relative rather than absolute addresses in its
exception table, so we add a sorter for these.  If there are
relocations on the __ex_table section, they are redundant and probably
incorrect after the sort, so they are zeroed out leaving them valid
and consistent.

Also use the unaligned safe accessors from tools/{be,le}_byteshift.h
Signed-off-by: default avatarDavid Daney <david.daney@cavium.com>
Link: http://lkml.kernel.org/r/1335291795-26693-2-git-send-email-ddaney.cavm@gmail.comSigned-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 70627654
......@@ -15,6 +15,8 @@ hostprogs-$(CONFIG_IKCONFIG) += bin2c
hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount
hostprogs-$(CONFIG_BUILDTIME_EXTABLE_SORT) += sortextable
HOSTCFLAGS_sortextable.o = -I$(srctree)/tools/include
always := $(hostprogs-y) $(hostprogs-m)
# The following hostprogs-y programs are only build on demand
......
/*
* sortextable.c: Sort the kernel's exception table
*
* Copyright 2011 Cavium, Inc.
* Copyright 2011 - 2012 Cavium, Inc.
*
* Based on code taken from recortmcount.c which is:
*
......@@ -28,6 +28,9 @@
#include <string.h>
#include <unistd.h>
#include <tools/be_byteshift.h>
#include <tools/le_byteshift.h>
static int fd_map; /* File descriptor for file being modified. */
static int mmap_failed; /* Boolean flag. */
static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
......@@ -94,109 +97,157 @@ static void *mmap_file(char const *fname)
return addr;
}
/* w8rev, w8nat, ...: Handle endianness. */
static uint64_t w8rev(uint64_t const x)
static uint64_t r8be(const uint64_t *x)
{
return ((0xff & (x >> (0 * 8))) << (7 * 8))
| ((0xff & (x >> (1 * 8))) << (6 * 8))
| ((0xff & (x >> (2 * 8))) << (5 * 8))
| ((0xff & (x >> (3 * 8))) << (4 * 8))
| ((0xff & (x >> (4 * 8))) << (3 * 8))
| ((0xff & (x >> (5 * 8))) << (2 * 8))
| ((0xff & (x >> (6 * 8))) << (1 * 8))
| ((0xff & (x >> (7 * 8))) << (0 * 8));
return get_unaligned_be64(x);
}
static uint32_t w4rev(uint32_t const x)
static uint32_t rbe(const uint32_t *x)
{
return ((0xff & (x >> (0 * 8))) << (3 * 8))
| ((0xff & (x >> (1 * 8))) << (2 * 8))
| ((0xff & (x >> (2 * 8))) << (1 * 8))
| ((0xff & (x >> (3 * 8))) << (0 * 8));
return get_unaligned_be32(x);
}
static uint32_t w2rev(uint16_t const x)
static uint16_t r2be(const uint16_t *x)
{
return ((0xff & (x >> (0 * 8))) << (1 * 8))
| ((0xff & (x >> (1 * 8))) << (0 * 8));
return get_unaligned_be16(x);
}
static uint64_t w8nat(uint64_t const x)
static uint64_t r8le(const uint64_t *x)
{
return x;
return get_unaligned_le64(x);
}
static uint32_t w4nat(uint32_t const x)
static uint32_t rle(const uint32_t *x)
{
return get_unaligned_le32(x);
}
static uint16_t r2le(const uint16_t *x)
{
return x;
return get_unaligned_le16(x);
}
static uint32_t w2nat(uint16_t const x)
static void w8be(uint64_t val, uint64_t *x)
{
put_unaligned_be64(val, x);
}
static void wbe(uint32_t val, uint32_t *x)
{
put_unaligned_be32(val, x);
}
static void w2be(uint16_t val, uint16_t *x)
{
put_unaligned_be16(val, x);
}
static void w8le(uint64_t val, uint64_t *x)
{
put_unaligned_le64(val, x);
}
static void wle(uint32_t val, uint32_t *x)
{
put_unaligned_le32(val, x);
}
static void w2le(uint16_t val, uint16_t *x)
{
return x;
put_unaligned_le16(val, x);
}
static uint64_t (*w8)(uint64_t);
static uint32_t (*w)(uint32_t);
static uint32_t (*w2)(uint16_t);
static uint64_t (*r8)(const uint64_t *);
static uint32_t (*r)(const uint32_t *);
static uint16_t (*r2)(const uint16_t *);
static void (*w8)(uint64_t, uint64_t *);
static void (*w)(uint32_t, uint32_t *);
static void (*w2)(uint16_t, uint16_t *);
typedef void (*table_sort_t)(char *, int);
/* 32 bit and 64 bit are very similar */
#include "sortextable.h"
#define SORTEXTABLE_64
#include "sortextable.h"
static int compare_x86_table(const void *a, const void *b)
{
int32_t av = (int32_t)r(a);
int32_t bv = (int32_t)r(b);
if (av < bv)
return -1;
if (av > bv)
return 1;
return 0;
}
static void sort_x86_table(char *extab_image, int image_size)
{
int i;
/*
* Do the same thing the runtime sort does, first normalize to
* being relative to the start of the section.
*/
i = 0;
while (i < image_size) {
uint32_t *loc = (uint32_t *)(extab_image + i);
w(r(loc) + i, loc);
i += 4;
}
qsort(extab_image, image_size / 8, 8, compare_x86_table);
/* Now denormalize. */
i = 0;
while (i < image_size) {
uint32_t *loc = (uint32_t *)(extab_image + i);
w(r(loc) - i, loc);
i += 4;
}
}
static void
do_file(char const *const fname)
{
Elf32_Ehdr *const ehdr = mmap_file(fname);
table_sort_t custom_sort;
Elf32_Ehdr *ehdr = mmap_file(fname);
ehdr_curr = ehdr;
w = w4nat;
w2 = w2nat;
w8 = w8nat;
switch (ehdr->e_ident[EI_DATA]) {
static unsigned int const endian = 1;
default:
fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
ehdr->e_ident[EI_DATA], fname);
fail_file();
break;
case ELFDATA2LSB:
if (*(unsigned char const *)&endian != 1) {
/* main() is big endian, file.o is little endian. */
w = w4rev;
w2 = w2rev;
w8 = w8rev;
}
r = rle;
r2 = r2le;
r8 = r8le;
w = wle;
w2 = w2le;
w8 = w8le;
break;
case ELFDATA2MSB:
if (*(unsigned char const *)&endian != 0) {
/* main() is little endian, file.o is big endian. */
w = w4rev;
w2 = w2rev;
w8 = w8rev;
}
r = rbe;
r2 = r2be;
r8 = r8be;
w = wbe;
w2 = w2be;
w8 = w8be;
break;
} /* end switch */
if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
|| w2(ehdr->e_type) != ET_EXEC
|| r2(&ehdr->e_type) != ET_EXEC
|| ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname);
fail_file();
}
switch (w2(ehdr->e_machine)) {
custom_sort = NULL;
switch (r2(&ehdr->e_machine)) {
default:
fprintf(stderr, "unrecognized e_machine %d %s\n",
w2(ehdr->e_machine), fname);
r2(&ehdr->e_machine), fname);
fail_file();
break;
case EM_386:
case EM_MIPS:
case EM_X86_64:
custom_sort = sort_x86_table;
break;
case EM_MIPS:
break;
} /* end switch */
......@@ -207,23 +258,23 @@ do_file(char const *const fname)
fail_file();
break;
case ELFCLASS32:
if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
|| w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
|| r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
fprintf(stderr,
"unrecognized ET_EXEC file: %s\n", fname);
fail_file();
}
do32(ehdr, fname);
do32(ehdr, fname, custom_sort);
break;
case ELFCLASS64: {
Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
|| w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
|| r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
fprintf(stderr,
"unrecognized ET_EXEC file: %s\n", fname);
fail_file();
}
do64(ghdr, fname);
do64(ghdr, fname, custom_sort);
break;
}
} /* end switch */
......
/*
* sortextable.h
*
* Copyright 2011 Cavium, Inc.
* Copyright 2011 - 2012 Cavium, Inc.
*
* Some of this code was taken out of recordmcount.h written by:
*
......@@ -30,6 +30,7 @@
#undef fn_ELF_R_SYM
#undef fn_ELF_R_INFO
#undef uint_t
#undef _r
#undef _w
#ifdef SORTEXTABLE_64
......@@ -51,6 +52,7 @@
# define fn_ELF_R_SYM fn_ELF64_R_SYM
# define fn_ELF_R_INFO fn_ELF64_R_INFO
# define uint_t uint64_t
# define _r r8
# define _w w8
#else
# define extable_ent_size 8
......@@ -71,23 +73,24 @@
# define fn_ELF_R_SYM fn_ELF32_R_SYM
# define fn_ELF_R_INFO fn_ELF32_R_INFO
# define uint_t uint32_t
# define _r r
# define _w w
#endif
static int compare_extable(const void *a, const void *b)
{
const uint_t *aa = a;
const uint_t *bb = b;
Elf_Addr av = _r(a);
Elf_Addr bv = _r(b);
if (_w(*aa) < _w(*bb))
if (av < bv)
return -1;
if (_w(*aa) > _w(*bb))
if (av > bv)
return 1;
return 0;
}
static void
do_func(Elf_Ehdr *const ehdr, char const *const fname)
do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort)
{
Elf_Shdr *shdr;
Elf_Shdr *shstrtab_sec;
......@@ -97,19 +100,31 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname)
Elf_Sym *sym;
Elf_Sym *sort_needed_sym;
Elf_Shdr *sort_needed_sec;
Elf_Rel *relocs = NULL;
int relocs_size;
uint32_t *sort_done_location;
const char *secstrtab;
const char *strtab;
char *extab_image;
int extab_index = 0;
int i;
int idx;
shdr = (Elf_Shdr *)((void *)ehdr + _w(ehdr->e_shoff));
shstrtab_sec = shdr + w2(ehdr->e_shstrndx);
secstrtab = (const char *)ehdr + _w(shstrtab_sec->sh_offset);
for (i = 0; i < w2(ehdr->e_shnum); i++) {
idx = w(shdr[i].sh_name);
if (strcmp(secstrtab + idx, "__ex_table") == 0)
shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
shstrtab_sec = shdr + r2(&ehdr->e_shstrndx);
secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
for (i = 0; i < r2(&ehdr->e_shnum); i++) {
idx = r(&shdr[i].sh_name);
if (strcmp(secstrtab + idx, "__ex_table") == 0) {
extab_sec = shdr + i;
extab_index = i;
}
if ((r(&shdr[i].sh_type) == SHT_REL ||
r(&shdr[i].sh_type) == SHT_RELA) &&
r(&shdr[i].sh_info) == extab_index) {
relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
relocs_size = _r(&shdr[i].sh_size);
}
if (strcmp(secstrtab + idx, ".symtab") == 0)
symtab_sec = shdr + i;
if (strcmp(secstrtab + idx, ".strtab") == 0)
......@@ -127,21 +142,29 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname)
fprintf(stderr, "no __ex_table in file: %s\n", fname);
fail_file();
}
strtab = (const char *)ehdr + _w(strtab_sec->sh_offset);
strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
/* Sort the table in place */
qsort((void *)ehdr + _w(extab_sec->sh_offset),
(_w(extab_sec->sh_size) / extable_ent_size),
extable_ent_size, compare_extable);
extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
if (custom_sort) {
custom_sort(extab_image, _r(&extab_sec->sh_size));
} else {
int num_entries = _r(&extab_sec->sh_size) / extable_ent_size;
qsort(extab_image, num_entries,
extable_ent_size, compare_extable);
}
/* If there were relocations, we no longer need them. */
if (relocs)
memset(relocs, 0, relocs_size);
/* find main_extable_sort_needed */
sort_needed_sym = NULL;
for (i = 0; i < _w(symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
sym = (void *)ehdr + _w(symtab_sec->sh_offset);
for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
sym += i;
if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
continue;
idx = w(sym->st_name);
idx = r(&sym->st_name);
if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) {
sort_needed_sym = sym;
break;
......@@ -153,16 +176,16 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname)
fname);
fail_file();
}
sort_needed_sec = &shdr[w2(sort_needed_sym->st_shndx)];
sort_needed_sec = &shdr[r2(&sort_needed_sym->st_shndx)];
sort_done_location = (void *)ehdr +
_w(sort_needed_sec->sh_offset) +
_w(sort_needed_sym->st_value) -
_w(sort_needed_sec->sh_addr);
_r(&sort_needed_sec->sh_offset) +
_r(&sort_needed_sym->st_value) -
_r(&sort_needed_sec->sh_addr);
#if 1
printf("sort done marker at %lx\n",
(unsigned long) (_w(sort_needed_sec->sh_offset) +
_w(sort_needed_sym->st_value) -
_w(sort_needed_sec->sh_addr)));
(unsigned long)((char *)sort_done_location - (char *)ehdr));
#endif
/* We sorted it, clear the flag. */
*sort_done_location = 0;
w(0, sort_done_location);
}
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