1/* 2 * sortextable.h 3 * 4 * Copyright 2011 - 2012 Cavium, Inc. 5 * 6 * Some of this code was taken out of recordmcount.h written by: 7 * 8 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved. 9 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc. 10 * 11 * 12 * Licensed under the GNU General Public License, version 2 (GPLv2). 13 */ 14 15#undef extable_ent_size 16#undef compare_extable 17#undef do_func 18#undef Elf_Addr 19#undef Elf_Ehdr 20#undef Elf_Shdr 21#undef Elf_Rel 22#undef Elf_Rela 23#undef Elf_Sym 24#undef ELF_R_SYM 25#undef Elf_r_sym 26#undef ELF_R_INFO 27#undef Elf_r_info 28#undef ELF_ST_BIND 29#undef ELF_ST_TYPE 30#undef fn_ELF_R_SYM 31#undef fn_ELF_R_INFO 32#undef uint_t 33#undef _r 34#undef _w 35 36#ifdef SORTEXTABLE_64 37# define extable_ent_size 16 38# define compare_extable compare_extable_64 39# define do_func do64 40# define Elf_Addr Elf64_Addr 41# define Elf_Ehdr Elf64_Ehdr 42# define Elf_Shdr Elf64_Shdr 43# define Elf_Rel Elf64_Rel 44# define Elf_Rela Elf64_Rela 45# define Elf_Sym Elf64_Sym 46# define ELF_R_SYM ELF64_R_SYM 47# define Elf_r_sym Elf64_r_sym 48# define ELF_R_INFO ELF64_R_INFO 49# define Elf_r_info Elf64_r_info 50# define ELF_ST_BIND ELF64_ST_BIND 51# define ELF_ST_TYPE ELF64_ST_TYPE 52# define fn_ELF_R_SYM fn_ELF64_R_SYM 53# define fn_ELF_R_INFO fn_ELF64_R_INFO 54# define uint_t uint64_t 55# define _r r8 56# define _w w8 57#else 58# define extable_ent_size 8 59# define compare_extable compare_extable_32 60# define do_func do32 61# define Elf_Addr Elf32_Addr 62# define Elf_Ehdr Elf32_Ehdr 63# define Elf_Shdr Elf32_Shdr 64# define Elf_Rel Elf32_Rel 65# define Elf_Rela Elf32_Rela 66# define Elf_Sym Elf32_Sym 67# define ELF_R_SYM ELF32_R_SYM 68# define Elf_r_sym Elf32_r_sym 69# define ELF_R_INFO ELF32_R_INFO 70# define Elf_r_info Elf32_r_info 71# define ELF_ST_BIND ELF32_ST_BIND 72# define ELF_ST_TYPE ELF32_ST_TYPE 73# define fn_ELF_R_SYM fn_ELF32_R_SYM 74# define fn_ELF_R_INFO fn_ELF32_R_INFO 75# define uint_t uint32_t 76# define _r r 77# define _w w 78#endif 79 80static int compare_extable(const void *a, const void *b) 81{ 82 Elf_Addr av = _r(a); 83 Elf_Addr bv = _r(b); 84 85 if (av < bv) 86 return -1; 87 if (av > bv) 88 return 1; 89 return 0; 90} 91 92static void 93do_func(Elf_Ehdr *ehdr, char const *const fname, table_sort_t custom_sort) 94{ 95 Elf_Shdr *shdr; 96 Elf_Shdr *shstrtab_sec; 97 Elf_Shdr *strtab_sec = NULL; 98 Elf_Shdr *symtab_sec = NULL; 99 Elf_Shdr *extab_sec = NULL; 100 Elf_Sym *sym; 101 const Elf_Sym *symtab; 102 Elf32_Word *symtab_shndx_start = NULL; 103 Elf_Sym *sort_needed_sym; 104 Elf_Shdr *sort_needed_sec; 105 Elf_Rel *relocs = NULL; 106 int relocs_size = 0; 107 uint32_t *sort_done_location; 108 const char *secstrtab; 109 const char *strtab; 110 char *extab_image; 111 int extab_index = 0; 112 int i; 113 int idx; 114 unsigned int num_sections; 115 unsigned int secindex_strings; 116 117 shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff)); 118 119 num_sections = r2(&ehdr->e_shnum); 120 if (num_sections == SHN_UNDEF) 121 num_sections = _r(&shdr[0].sh_size); 122 123 secindex_strings = r2(&ehdr->e_shstrndx); 124 if (secindex_strings == SHN_XINDEX) 125 secindex_strings = r(&shdr[0].sh_link); 126 127 shstrtab_sec = shdr + secindex_strings; 128 secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset); 129 for (i = 0; i < num_sections; i++) { 130 idx = r(&shdr[i].sh_name); 131 if (strcmp(secstrtab + idx, "__ex_table") == 0) { 132 extab_sec = shdr + i; 133 extab_index = i; 134 } 135 if ((r(&shdr[i].sh_type) == SHT_REL || 136 r(&shdr[i].sh_type) == SHT_RELA) && 137 r(&shdr[i].sh_info) == extab_index) { 138 relocs = (void *)ehdr + _r(&shdr[i].sh_offset); 139 relocs_size = _r(&shdr[i].sh_size); 140 } 141 if (strcmp(secstrtab + idx, ".symtab") == 0) 142 symtab_sec = shdr + i; 143 if (strcmp(secstrtab + idx, ".strtab") == 0) 144 strtab_sec = shdr + i; 145 if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX) 146 symtab_shndx_start = (Elf32_Word *)( 147 (const char *)ehdr + _r(&shdr[i].sh_offset)); 148 } 149 if (strtab_sec == NULL) { 150 fprintf(stderr, "no .strtab in file: %s\n", fname); 151 fail_file(); 152 } 153 if (symtab_sec == NULL) { 154 fprintf(stderr, "no .symtab in file: %s\n", fname); 155 fail_file(); 156 } 157 symtab = (const Elf_Sym *)((const char *)ehdr + 158 _r(&symtab_sec->sh_offset)); 159 if (extab_sec == NULL) { 160 fprintf(stderr, "no __ex_table in file: %s\n", fname); 161 fail_file(); 162 } 163 strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset); 164 165 extab_image = (void *)ehdr + _r(&extab_sec->sh_offset); 166 167 if (custom_sort) { 168 custom_sort(extab_image, _r(&extab_sec->sh_size)); 169 } else { 170 int num_entries = _r(&extab_sec->sh_size) / extable_ent_size; 171 qsort(extab_image, num_entries, 172 extable_ent_size, compare_extable); 173 } 174 /* If there were relocations, we no longer need them. */ 175 if (relocs) 176 memset(relocs, 0, relocs_size); 177 178 /* find main_extable_sort_needed */ 179 sort_needed_sym = NULL; 180 for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) { 181 sym = (void *)ehdr + _r(&symtab_sec->sh_offset); 182 sym += i; 183 if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT) 184 continue; 185 idx = r(&sym->st_name); 186 if (strcmp(strtab + idx, "main_extable_sort_needed") == 0) { 187 sort_needed_sym = sym; 188 break; 189 } 190 } 191 if (sort_needed_sym == NULL) { 192 fprintf(stderr, 193 "no main_extable_sort_needed symbol in file: %s\n", 194 fname); 195 fail_file(); 196 } 197 sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx), 198 sort_needed_sym - symtab, 199 symtab_shndx_start)]; 200 sort_done_location = (void *)ehdr + 201 _r(&sort_needed_sec->sh_offset) + 202 _r(&sort_needed_sym->st_value) - 203 _r(&sort_needed_sec->sh_addr); 204 205#if 0 206 printf("sort done marker at %lx\n", 207 (unsigned long)((char *)sort_done_location - (char *)ehdr)); 208#endif 209 /* We sorted it, clear the flag. */ 210 w(0, sort_done_location); 211} 212