mirror of
https://github.com/torvalds/linux.git
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0de798584b
Switch to the generic extable search and sort routines which were introduced
with commit a272858 from Ard Biesheuvel. This saves quite some memory in the
vmlinux binary with the 64bit kernel.
Signed-off-by: Helge Deller <deller@gmx.de>
399 lines
8.3 KiB
C
399 lines
8.3 KiB
C
/*
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* sortextable.c: Sort the kernel's exception table
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*
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* Copyright 2011 - 2012 Cavium, Inc.
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*
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* Based on code taken from recortmcount.c which is:
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*
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* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
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* Licensed under the GNU General Public License, version 2 (GPLv2).
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*
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* Restructured to fit Linux format, as well as other updates:
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* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
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*/
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/*
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* Strategy: alter the vmlinux file in-place.
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*/
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <getopt.h>
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#include <elf.h>
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#include <fcntl.h>
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#include <setjmp.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <tools/be_byteshift.h>
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#include <tools/le_byteshift.h>
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#ifndef EM_ARCOMPACT
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#define EM_ARCOMPACT 93
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#endif
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#ifndef EM_XTENSA
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#define EM_XTENSA 94
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#endif
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#ifndef EM_AARCH64
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#define EM_AARCH64 183
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#endif
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#ifndef EM_MICROBLAZE
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#define EM_MICROBLAZE 189
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#endif
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#ifndef EM_ARCV2
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#define EM_ARCV2 195
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#endif
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static int fd_map; /* File descriptor for file being modified. */
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static int mmap_failed; /* Boolean flag. */
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static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
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static struct stat sb; /* Remember .st_size, etc. */
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static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
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/* setjmp() return values */
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enum {
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SJ_SETJMP = 0, /* hardwired first return */
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SJ_FAIL,
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SJ_SUCCEED
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};
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/* Per-file resource cleanup when multiple files. */
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static void
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cleanup(void)
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{
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if (!mmap_failed)
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munmap(ehdr_curr, sb.st_size);
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close(fd_map);
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}
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static void __attribute__((noreturn))
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fail_file(void)
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{
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cleanup();
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longjmp(jmpenv, SJ_FAIL);
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}
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/*
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* Get the whole file as a programming convenience in order to avoid
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* malloc+lseek+read+free of many pieces. If successful, then mmap
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* avoids copying unused pieces; else just read the whole file.
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* Open for both read and write.
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*/
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static void *mmap_file(char const *fname)
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{
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void *addr;
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fd_map = open(fname, O_RDWR);
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if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
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perror(fname);
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fail_file();
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}
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if (!S_ISREG(sb.st_mode)) {
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fprintf(stderr, "not a regular file: %s\n", fname);
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fail_file();
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}
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addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED,
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fd_map, 0);
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if (addr == MAP_FAILED) {
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mmap_failed = 1;
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fprintf(stderr, "Could not mmap file: %s\n", fname);
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fail_file();
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}
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return addr;
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}
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static uint64_t r8be(const uint64_t *x)
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{
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return get_unaligned_be64(x);
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}
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static uint32_t rbe(const uint32_t *x)
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{
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return get_unaligned_be32(x);
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}
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static uint16_t r2be(const uint16_t *x)
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{
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return get_unaligned_be16(x);
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}
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static uint64_t r8le(const uint64_t *x)
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{
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return get_unaligned_le64(x);
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}
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static uint32_t rle(const uint32_t *x)
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{
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return get_unaligned_le32(x);
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}
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static uint16_t r2le(const uint16_t *x)
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{
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return get_unaligned_le16(x);
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}
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static void w8be(uint64_t val, uint64_t *x)
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{
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put_unaligned_be64(val, x);
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}
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static void wbe(uint32_t val, uint32_t *x)
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{
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put_unaligned_be32(val, x);
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}
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static void w2be(uint16_t val, uint16_t *x)
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{
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put_unaligned_be16(val, x);
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}
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static void w8le(uint64_t val, uint64_t *x)
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{
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put_unaligned_le64(val, x);
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}
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static void wle(uint32_t val, uint32_t *x)
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{
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put_unaligned_le32(val, x);
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}
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static void w2le(uint16_t val, uint16_t *x)
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{
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put_unaligned_le16(val, x);
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}
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static uint64_t (*r8)(const uint64_t *);
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static uint32_t (*r)(const uint32_t *);
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static uint16_t (*r2)(const uint16_t *);
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static void (*w8)(uint64_t, uint64_t *);
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static void (*w)(uint32_t, uint32_t *);
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static void (*w2)(uint16_t, uint16_t *);
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typedef void (*table_sort_t)(char *, int);
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/*
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* Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
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* the way to -256..-1, to avoid conflicting with real section
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* indices.
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*/
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#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
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static inline int is_shndx_special(unsigned int i)
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{
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return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
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}
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/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
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static inline unsigned int get_secindex(unsigned int shndx,
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unsigned int sym_offs,
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const Elf32_Word *symtab_shndx_start)
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{
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if (is_shndx_special(shndx))
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return SPECIAL(shndx);
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if (shndx != SHN_XINDEX)
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return shndx;
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return r(&symtab_shndx_start[sym_offs]);
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}
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/* 32 bit and 64 bit are very similar */
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#include "sortextable.h"
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#define SORTEXTABLE_64
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#include "sortextable.h"
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static int compare_relative_table(const void *a, const void *b)
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{
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int32_t av = (int32_t)r(a);
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int32_t bv = (int32_t)r(b);
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if (av < bv)
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return -1;
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if (av > bv)
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return 1;
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return 0;
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}
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static void x86_sort_relative_table(char *extab_image, int image_size)
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{
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int i;
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i = 0;
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while (i < image_size) {
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uint32_t *loc = (uint32_t *)(extab_image + i);
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w(r(loc) + i, loc);
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w(r(loc + 1) + i + 4, loc + 1);
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w(r(loc + 2) + i + 8, loc + 2);
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i += sizeof(uint32_t) * 3;
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}
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qsort(extab_image, image_size / 12, 12, compare_relative_table);
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i = 0;
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while (i < image_size) {
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uint32_t *loc = (uint32_t *)(extab_image + i);
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w(r(loc) - i, loc);
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w(r(loc + 1) - (i + 4), loc + 1);
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w(r(loc + 2) - (i + 8), loc + 2);
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i += sizeof(uint32_t) * 3;
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}
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}
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static void sort_relative_table(char *extab_image, int image_size)
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{
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int i;
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/*
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* Do the same thing the runtime sort does, first normalize to
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* being relative to the start of the section.
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*/
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i = 0;
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while (i < image_size) {
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uint32_t *loc = (uint32_t *)(extab_image + i);
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w(r(loc) + i, loc);
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i += 4;
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}
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qsort(extab_image, image_size / 8, 8, compare_relative_table);
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/* Now denormalize. */
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i = 0;
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while (i < image_size) {
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uint32_t *loc = (uint32_t *)(extab_image + i);
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w(r(loc) - i, loc);
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i += 4;
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}
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}
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static void
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do_file(char const *const fname)
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{
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table_sort_t custom_sort;
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Elf32_Ehdr *ehdr = mmap_file(fname);
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ehdr_curr = ehdr;
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switch (ehdr->e_ident[EI_DATA]) {
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default:
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fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
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ehdr->e_ident[EI_DATA], fname);
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fail_file();
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break;
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case ELFDATA2LSB:
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r = rle;
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r2 = r2le;
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r8 = r8le;
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w = wle;
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w2 = w2le;
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w8 = w8le;
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break;
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case ELFDATA2MSB:
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r = rbe;
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r2 = r2be;
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r8 = r8be;
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w = wbe;
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w2 = w2be;
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w8 = w8be;
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break;
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} /* end switch */
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if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
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|| (r2(&ehdr->e_type) != ET_EXEC && r2(&ehdr->e_type) != ET_DYN)
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|| ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
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fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file %s\n", fname);
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fail_file();
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}
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custom_sort = NULL;
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switch (r2(&ehdr->e_machine)) {
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default:
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fprintf(stderr, "unrecognized e_machine %d %s\n",
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r2(&ehdr->e_machine), fname);
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fail_file();
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break;
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case EM_386:
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case EM_X86_64:
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custom_sort = x86_sort_relative_table;
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break;
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case EM_S390:
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case EM_AARCH64:
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case EM_PARISC:
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custom_sort = sort_relative_table;
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break;
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case EM_ARCOMPACT:
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case EM_ARCV2:
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case EM_ARM:
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case EM_MICROBLAZE:
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case EM_MIPS:
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case EM_XTENSA:
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break;
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} /* end switch */
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switch (ehdr->e_ident[EI_CLASS]) {
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default:
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fprintf(stderr, "unrecognized ELF class %d %s\n",
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ehdr->e_ident[EI_CLASS], fname);
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fail_file();
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break;
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case ELFCLASS32:
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if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
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|| r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
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fprintf(stderr,
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"unrecognized ET_EXEC/ET_DYN file: %s\n", fname);
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fail_file();
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}
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do32(ehdr, fname, custom_sort);
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break;
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case ELFCLASS64: {
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Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
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if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr)
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|| r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
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fprintf(stderr,
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"unrecognized ET_EXEC/ET_DYN file: %s\n", fname);
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fail_file();
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}
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do64(ghdr, fname, custom_sort);
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break;
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}
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} /* end switch */
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cleanup();
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}
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int
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main(int argc, char *argv[])
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{
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int n_error = 0; /* gcc-4.3.0 false positive complaint */
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int i;
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if (argc < 2) {
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fprintf(stderr, "usage: sortextable vmlinux...\n");
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return 0;
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}
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/* Process each file in turn, allowing deep failure. */
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for (i = 1; i < argc; i++) {
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char *file = argv[i];
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int const sjval = setjmp(jmpenv);
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switch (sjval) {
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default:
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fprintf(stderr, "internal error: %s\n", file);
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exit(1);
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break;
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case SJ_SETJMP: /* normal sequence */
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/* Avoid problems if early cleanup() */
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fd_map = -1;
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ehdr_curr = NULL;
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mmap_failed = 1;
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do_file(file);
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break;
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case SJ_FAIL: /* error in do_file or below */
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++n_error;
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break;
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case SJ_SUCCEED: /* premature success */
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/* do nothing */
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break;
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} /* end switch */
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}
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return !!n_error;
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}
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