diff options
| -rw-r--r-- | scripts/.gitignore | 1 | ||||
| -rw-r--r-- | scripts/Makefile | 1 | ||||
| -rw-r--r-- | scripts/sortextable.c | 271 | ||||
| -rw-r--r-- | scripts/sortextable.h | 168 |
4 files changed, 441 insertions, 0 deletions
diff --git a/scripts/.gitignore b/scripts/.gitignore index 105b21f08185..65f362d931b5 100644 --- a/scripts/.gitignore +++ b/scripts/.gitignore @@ -9,3 +9,4 @@ unifdef ihex2fw recordmcount docproc +sortextable diff --git a/scripts/Makefile b/scripts/Makefile index df7678febf27..43e19b9fc641 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -13,6 +13,7 @@ hostprogs-$(CONFIG_LOGO) += pnmtologo hostprogs-$(CONFIG_VT) += conmakehash hostprogs-$(CONFIG_IKCONFIG) += bin2c hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount +hostprogs-$(CONFIG_BUILDTIME_EXTABLE_SORT) += sortextable always := $(hostprogs-y) $(hostprogs-m) diff --git a/scripts/sortextable.c b/scripts/sortextable.c new file mode 100644 index 000000000000..f51f1d43da63 --- /dev/null +++ b/scripts/sortextable.c @@ -0,0 +1,271 @@ +/* + * sortextable.c: Sort the kernel's exception table + * + * Copyright 2011 Cavium, Inc. + * + * Based on code taken from recortmcount.c which is: + * + * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved. + * Licensed under the GNU General Public License, version 2 (GPLv2). + * + * Restructured to fit Linux format, as well as other updates: + * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc. + */ + +/* + * Strategy: alter the vmlinux file in-place. + */ + +#include <sys/types.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <getopt.h> +#include <elf.h> +#include <fcntl.h> +#include <setjmp.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.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 */ +static struct stat sb; /* Remember .st_size, etc. */ +static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */ + +/* setjmp() return values */ +enum { + SJ_SETJMP = 0, /* hardwired first return */ + SJ_FAIL, + SJ_SUCCEED +}; + +/* Per-file resource cleanup when multiple files. */ +static void +cleanup(void) +{ + if (!mmap_failed) + munmap(ehdr_curr, sb.st_size); + close(fd_map); +} + +static void __attribute__((noreturn)) +fail_file(void) +{ + cleanup(); + longjmp(jmpenv, SJ_FAIL); +} + +static void __attribute__((noreturn)) +succeed_file(void) +{ + cleanup(); + longjmp(jmpenv, SJ_SUCCEED); +} + + +/* + * Get the whole file as a programming convenience in order to avoid + * malloc+lseek+read+free of many pieces. If successful, then mmap + * avoids copying unused pieces; else just read the whole file. + * Open for both read and write. + */ +static void *mmap_file(char const *fname) +{ + void *addr; + + fd_map = open(fname, O_RDWR); + if (fd_map < 0 || fstat(fd_map, &sb) < 0) { + perror(fname); + fail_file(); + } + if (!S_ISREG(sb.st_mode)) { + fprintf(stderr, "not a regular file: %s\n", fname); + fail_file(); + } + addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, + fd_map, 0); + if (addr == MAP_FAILED) { + mmap_failed = 1; + fprintf(stderr, "Could not mmap file: %s\n", fname); + fail_file(); + } + return addr; +} + +/* w8rev, w8nat, ...: Handle endianness. */ + +static uint64_t w8rev(uint64_t const 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)); +} + +static uint32_t w4rev(uint32_t const 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)); +} + +static uint32_t w2rev(uint16_t const x) +{ + return ((0xff & (x >> (0 * 8))) << (1 * 8)) + | ((0xff & (x >> (1 * 8))) << (0 * 8)); +} + +static uint64_t w8nat(uint64_t const x) +{ + return x; +} + +static uint32_t w4nat(uint32_t const x) +{ + return x; +} + +static uint32_t w2nat(uint16_t const x) +{ + return x; +} + +static uint64_t (*w8)(uint64_t); +static uint32_t (*w)(uint32_t); +static uint32_t (*w2)(uint16_t); + + +/* 32 bit and 64 bit are very similar */ +#include "sortextable.h" +#define SORTEXTABLE_64 +#include "sortextable.h" + + +static void +do_file(char const *const fname) +{ + Elf32_Ehdr *const 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; + } + break; + case ELFDATA2MSB: + if (*(unsigned char const *)&endian != 0) { + /* main() is little endian, file.o is big endian. */ + w = w4rev; + w2 = w2rev; + w8 = w8rev; + } + break; + } /* end switch */ + if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 + || w2(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)) { + default: + fprintf(stderr, "unrecognized e_machine %d %s\n", + w2(ehdr->e_machine), fname); + fail_file(); + break; + case EM_386: + case EM_MIPS: + case EM_X86_64: + break; + } /* end switch */ + + switch (ehdr->e_ident[EI_CLASS]) { + default: + fprintf(stderr, "unrecognized ELF class %d %s\n", + ehdr->e_ident[EI_CLASS], fname); + fail_file(); + break; + case ELFCLASS32: + if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr) + || w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { + fprintf(stderr, + "unrecognized ET_EXEC file: %s\n", fname); + fail_file(); + } + do32(ehdr, fname); + 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)) { + fprintf(stderr, + "unrecognized ET_EXEC file: %s\n", fname); + fail_file(); + } + do64(ghdr, fname); + break; + } + } /* end switch */ + + cleanup(); +} + +int +main(int argc, char *argv[]) +{ + int n_error = 0; /* gcc-4.3.0 false positive complaint */ + int i; + + if (argc < 2) { + fprintf(stderr, "usage: sortextable vmlinux...\n"); + return 0; + } + + /* Process each file in turn, allowing deep failure. */ + for (i = 1; i < argc; i++) { + char *file = argv[i]; + int const sjval = setjmp(jmpenv); + + switch (sjval) { + default: + fprintf(stderr, "internal error: %s\n", file); + exit(1); + break; + case SJ_SETJMP: /* normal sequence */ + /* Avoid problems if early cleanup() */ + fd_map = -1; + ehdr_curr = NULL; + mmap_failed = 1; + do_file(file); + break; + case SJ_FAIL: /* error in do_file or below */ + ++n_error; + break; + case SJ_SUCCEED: /* premature success */ + /* do nothing */ + break; + } /* end switch */ + } + return !!n_error; +} diff --git a/scripts/sortextable.h b/scripts/sortextable.h new file mode 100644 index 000000000000..bb6aaf166002 --- /dev/null +++ b/scripts/sortextable.h @@ -0,0 +1,168 @@ +/* + * sortextable.h + * + * Copyright 2011 Cavium, Inc. + * + * 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. + * + * + * Licensed under the GNU General Public License, version 2 (GPLv2). + */ + +#undef extable_ent_size +#undef compare_extable +#undef do_func +#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 _w + +#ifdef SORTEXTABLE_64 +# define extable_ent_size 16 +# define compare_extable compare_extable_64 +# define do_func do64 +# 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 _w w8 +#else +# define extable_ent_size 8 +# define compare_extable compare_extable_32 +# define do_func do32 +# 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 _w w +#endif + +static int compare_extable(const void *a, const void *b) +{ + const uint_t *aa = a; + const uint_t *bb = b; + + if (_w(*aa) < _w(*bb)) + return -1; + if (_w(*aa) > _w(*bb)) + return 1; + return 0; +} + +static void +do_func(Elf_Ehdr *const ehdr, char const *const fname) +{ + Elf_Shdr *shdr; + Elf_Shdr *shstrtab_sec; + Elf_Shdr *strtab_sec = NULL; + Elf_Shdr *symtab_sec = NULL; + Elf_Shdr *extab_sec = NULL; + Elf_Sym *sym; + Elf_Sym *sort_needed_sym; + Elf_Shdr *sort_needed_sec; + uint32_t *sort_done_location; + const char *secstrtab; + const char *strtab; + 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) + extab_sec = shdr + i; + if (strcmp(secstrtab + idx, ".symtab") == 0) + symtab_sec = shdr + i; + if (strcmp(secstrtab + idx, ".strtab") == 0) + strtab_sec = shdr + i; + } + if (strtab_sec == NULL) { + fprintf(stderr, "no .strtab in file: %s\n", fname); + fail_file(); + } + if (symtab_sec == NULL) { + fprintf(stderr, "no .symtab in file: %s\n", fname); + fail_file(); + } + if (extab_sec == NULL) { + fprintf(stderr, "no __ex_table in file: %s\n", fname); + fail_file(); + } + strtab = (const char *)ehdr + _w(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); + + /* 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); + sym += i; + if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT) + continue; + idx = w(sym->st_name); + if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) { + sort_needed_sym = sym; + break; + } + } + if (sort_needed_sym == NULL) { + fprintf(stderr, + "no main_extable_sort_needed symbol in file: %s\n", + fname); + fail_file(); + } + sort_needed_sec = &shdr[w2(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); + + 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))); + /* We sorted it, clear the flag. */ + *sort_done_location = 0; +} |