linux-stable/scripts/sorttable.h
Shile Zhang 57fa189942 scripts/sorttable: Implement build-time ORC unwind table sorting
The ORC unwinder has two tables: .orc_unwind_ip and .orc_unwind, which
need to be sorted for binary search. Previously this sorting was done
during bootup.

Sort them at build time to speed up booting.

Add the ORC tables sorting in a parallel build process to speed up the build.

[ mingo: Rewrote the changelog and fixed some comments. ]

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-7-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-13 10:47:58 +01:00

380 lines
9.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* sorttable.h
*
* Added ORC unwind tables sort support and other updates:
* Copyright (C) 1999-2019 Alibaba Group Holding Limited. by:
* Shile Zhang <shile.zhang@linux.alibaba.com>
*
* Copyright 2011 - 2012 Cavium, Inc.
*
* Some of code was taken out of arch/x86/kernel/unwind_orc.c, written by:
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*
* Some of this code was taken out of recordmcount.h written by:
*
* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
*/
#undef extable_ent_size
#undef compare_extable
#undef do_sort
#undef Elf_Addr
#undef Elf_Ehdr
#undef Elf_Shdr
#undef Elf_Rel
#undef Elf_Rela
#undef Elf_Sym
#undef ELF_R_SYM
#undef Elf_r_sym
#undef ELF_R_INFO
#undef Elf_r_info
#undef ELF_ST_BIND
#undef ELF_ST_TYPE
#undef fn_ELF_R_SYM
#undef fn_ELF_R_INFO
#undef uint_t
#undef _r
#undef _w
#ifdef SORTTABLE_64
# define extable_ent_size 16
# define compare_extable compare_extable_64
# define do_sort do_sort_64
# define Elf_Addr Elf64_Addr
# define Elf_Ehdr Elf64_Ehdr
# define Elf_Shdr Elf64_Shdr
# define Elf_Rel Elf64_Rel
# define Elf_Rela Elf64_Rela
# define Elf_Sym Elf64_Sym
# define ELF_R_SYM ELF64_R_SYM
# define Elf_r_sym Elf64_r_sym
# define ELF_R_INFO ELF64_R_INFO
# define Elf_r_info Elf64_r_info
# define ELF_ST_BIND ELF64_ST_BIND
# define ELF_ST_TYPE ELF64_ST_TYPE
# 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
# define compare_extable compare_extable_32
# define do_sort do_sort_32
# define Elf_Addr Elf32_Addr
# define Elf_Ehdr Elf32_Ehdr
# define Elf_Shdr Elf32_Shdr
# define Elf_Rel Elf32_Rel
# define Elf_Rela Elf32_Rela
# define Elf_Sym Elf32_Sym
# define ELF_R_SYM ELF32_R_SYM
# define Elf_r_sym Elf32_r_sym
# define ELF_R_INFO ELF32_R_INFO
# define Elf_r_info Elf32_r_info
# define ELF_ST_BIND ELF32_ST_BIND
# define ELF_ST_TYPE ELF32_ST_TYPE
# 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
#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
/* ORC unwinder only support X86_64 */
#include <errno.h>
#include <pthread.h>
#include <asm/orc_types.h>
#define ERRSTR_MAXSZ 256
char g_err[ERRSTR_MAXSZ];
int *g_orc_ip_table;
struct orc_entry *g_orc_table;
pthread_t orc_sort_thread;
static inline unsigned long orc_ip(const int *ip)
{
return (unsigned long)ip + *ip;
}
static int orc_sort_cmp(const void *_a, const void *_b)
{
struct orc_entry *orc_a;
const int *a = g_orc_ip_table + *(int *)_a;
const int *b = g_orc_ip_table + *(int *)_b;
unsigned long a_val = orc_ip(a);
unsigned long b_val = orc_ip(b);
if (a_val > b_val)
return 1;
if (a_val < b_val)
return -1;
/*
* The "weak" section terminator entries need to always be on the left
* to ensure the lookup code skips them in favor of real entries.
* These terminator entries exist to handle any gaps created by
* whitelisted .o files which didn't get objtool generation.
*/
orc_a = g_orc_table + (a - g_orc_ip_table);
return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
}
static void *sort_orctable(void *arg)
{
int i;
int *idxs = NULL;
int *tmp_orc_ip_table = NULL;
struct orc_entry *tmp_orc_table = NULL;
unsigned int *orc_ip_size = (unsigned int *)arg;
unsigned int num_entries = *orc_ip_size / sizeof(int);
unsigned int orc_size = num_entries * sizeof(struct orc_entry);
idxs = (int *)malloc(*orc_ip_size);
if (!idxs) {
snprintf(g_err, ERRSTR_MAXSZ, "malloc idxs: %s",
strerror(errno));
pthread_exit(g_err);
}
tmp_orc_ip_table = (int *)malloc(*orc_ip_size);
if (!tmp_orc_ip_table) {
snprintf(g_err, ERRSTR_MAXSZ, "malloc tmp_orc_ip_table: %s",
strerror(errno));
pthread_exit(g_err);
}
tmp_orc_table = (struct orc_entry *)malloc(orc_size);
if (!tmp_orc_table) {
snprintf(g_err, ERRSTR_MAXSZ, "malloc tmp_orc_table: %s",
strerror(errno));
pthread_exit(g_err);
}
/* initialize indices array, convert ip_table to absolute address */
for (i = 0; i < num_entries; i++) {
idxs[i] = i;
tmp_orc_ip_table[i] = g_orc_ip_table[i] + i * sizeof(int);
}
memcpy(tmp_orc_table, g_orc_table, orc_size);
qsort(idxs, num_entries, sizeof(int), orc_sort_cmp);
for (i = 0; i < num_entries; i++) {
if (idxs[i] == i)
continue;
/* convert back to relative address */
g_orc_ip_table[i] = tmp_orc_ip_table[idxs[i]] - i * sizeof(int);
g_orc_table[i] = tmp_orc_table[idxs[i]];
}
free(idxs);
free(tmp_orc_ip_table);
free(tmp_orc_table);
pthread_exit(NULL);
}
#endif
static int compare_extable(const void *a, const void *b)
{
Elf_Addr av = _r(a);
Elf_Addr bv = _r(b);
if (av < bv)
return -1;
if (av > bv)
return 1;
return 0;
}
static int do_sort(Elf_Ehdr *ehdr,
char const *const fname,
table_sort_t custom_sort)
{
int rc = -1;
Elf_Shdr *s, *shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
Elf_Shdr *strtab_sec = NULL;
Elf_Shdr *symtab_sec = NULL;
Elf_Shdr *extab_sec = NULL;
Elf_Sym *sym;
const Elf_Sym *symtab;
Elf32_Word *symtab_shndx = NULL;
Elf_Sym *sort_needed_sym = NULL;
Elf_Shdr *sort_needed_sec;
Elf_Rel *relocs = NULL;
int relocs_size = 0;
uint32_t *sort_needed_loc;
const char *secstrings;
const char *strtab;
char *extab_image;
int extab_index = 0;
int i;
int idx;
unsigned int shnum;
unsigned int shstrndx;
#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
unsigned int orc_ip_size = 0;
unsigned int orc_size = 0;
unsigned int orc_num_entries = 0;
#endif
shstrndx = r2(&ehdr->e_shstrndx);
if (shstrndx == SHN_XINDEX)
shstrndx = r(&shdr[0].sh_link);
secstrings = (const char *)ehdr + _r(&shdr[shstrndx].sh_offset);
shnum = r2(&ehdr->e_shnum);
if (shnum == SHN_UNDEF)
shnum = _r(&shdr[0].sh_size);
for (i = 0, s = shdr; s < shdr + shnum; i++, s++) {
idx = r(&s->sh_name);
if (!strcmp(secstrings + idx, "__ex_table")) {
extab_sec = s;
extab_index = i;
}
if (!strcmp(secstrings + idx, ".symtab"))
symtab_sec = s;
if (!strcmp(secstrings + idx, ".strtab"))
strtab_sec = s;
if ((r(&s->sh_type) == SHT_REL ||
r(&s->sh_type) == SHT_RELA) &&
r(&s->sh_info) == extab_index) {
relocs = (void *)ehdr + _r(&s->sh_offset);
relocs_size = _r(&s->sh_size);
}
if (r(&s->sh_type) == SHT_SYMTAB_SHNDX)
symtab_shndx = (Elf32_Word *)((const char *)ehdr +
_r(&s->sh_offset));
#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
/* locate the ORC unwind tables */
if (!strcmp(secstrings + idx, ".orc_unwind_ip")) {
orc_ip_size = s->sh_size;
g_orc_ip_table = (int *)((void *)ehdr +
s->sh_offset);
}
if (!strcmp(secstrings + idx, ".orc_unwind")) {
orc_size = s->sh_size;
g_orc_table = (struct orc_entry *)((void *)ehdr +
s->sh_offset);
}
#endif
} /* for loop */
#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
if (!g_orc_ip_table || !g_orc_table) {
fprintf(stderr,
"incomplete ORC unwind tables in file: %s\n", fname);
goto out;
}
orc_num_entries = orc_ip_size / sizeof(int);
if (orc_ip_size % sizeof(int) != 0 ||
orc_size % sizeof(struct orc_entry) != 0 ||
orc_num_entries != orc_size / sizeof(struct orc_entry)) {
fprintf(stderr,
"inconsistent ORC unwind table entries in file: %s\n",
fname);
goto out;
}
/* create thread to sort ORC unwind tables concurrently */
if (pthread_create(&orc_sort_thread, NULL,
sort_orctable, &orc_ip_size)) {
fprintf(stderr,
"pthread_create orc_sort_thread failed '%s': %s\n",
strerror(errno), fname);
goto out;
}
#endif
if (!extab_sec) {
fprintf(stderr, "no __ex_table in file: %s\n", fname);
goto out;
}
if (!symtab_sec) {
fprintf(stderr, "no .symtab in file: %s\n", fname);
goto out;
}
if (!strtab_sec) {
fprintf(stderr, "no .strtab in file: %s\n", fname);
goto out;
}
extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
symtab = (const Elf_Sym *)((const char *)ehdr +
_r(&symtab_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 the flag main_extable_sort_needed */
for (sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
sym < sym + _r(&symtab_sec->sh_size) / sizeof(Elf_Sym);
sym++) {
if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
continue;
if (!strcmp(strtab + r(&sym->st_name),
"main_extable_sort_needed")) {
sort_needed_sym = sym;
break;
}
}
if (!sort_needed_sym) {
fprintf(stderr,
"no main_extable_sort_needed symbol in file: %s\n",
fname);
goto out;
}
sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
sort_needed_sym - symtab,
symtab_shndx)];
sort_needed_loc = (void *)ehdr +
_r(&sort_needed_sec->sh_offset) +
_r(&sort_needed_sym->st_value) -
_r(&sort_needed_sec->sh_addr);
/* extable has been sorted, clear the flag */
w(0, sort_needed_loc);
rc = 0;
out:
#if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
if (orc_sort_thread) {
void *retval = NULL;
/* wait for ORC tables sort done */
rc = pthread_join(orc_sort_thread, &retval);
if (rc)
fprintf(stderr,
"pthread_join failed '%s': %s\n",
strerror(errno), fname);
else if (retval) {
rc = -1;
fprintf(stderr,
"failed to sort ORC tables '%s': %s\n",
(char *)retval, fname);
}
}
#endif
return rc;
}