diff options
Diffstat (limited to 'scripts/sortextable.c')
| -rw-r--r-- | scripts/sortextable.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/scripts/sortextable.c b/scripts/sortextable.c new file mode 100644 index 00000000000..f51f1d43da6 --- /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; +} |