diff options
| author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
|---|---|---|
| committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
| commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
| tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /arch/x86/boot | |
| parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) | |
Diffstat (limited to 'arch/x86/boot')
| -rw-r--r-- | arch/x86/boot/compressed/relocs.c | 682 |
1 files changed, 682 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c new file mode 100644 index 00000000000..89bbf4e4d05 --- /dev/null +++ b/arch/x86/boot/compressed/relocs.c | |||
| @@ -0,0 +1,682 @@ | |||
| 1 | #include <stdio.h> | ||
| 2 | #include <stdarg.h> | ||
| 3 | #include <stdlib.h> | ||
| 4 | #include <stdint.h> | ||
| 5 | #include <string.h> | ||
| 6 | #include <errno.h> | ||
| 7 | #include <unistd.h> | ||
| 8 | #include <elf.h> | ||
| 9 | #include <byteswap.h> | ||
| 10 | #define USE_BSD | ||
| 11 | #include <endian.h> | ||
| 12 | #include <regex.h> | ||
| 13 | |||
| 14 | static void die(char *fmt, ...); | ||
| 15 | |||
| 16 | #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) | ||
| 17 | static Elf32_Ehdr ehdr; | ||
| 18 | static unsigned long reloc_count, reloc_idx; | ||
| 19 | static unsigned long *relocs; | ||
| 20 | |||
| 21 | struct section { | ||
| 22 | Elf32_Shdr shdr; | ||
| 23 | struct section *link; | ||
| 24 | Elf32_Sym *symtab; | ||
| 25 | Elf32_Rel *reltab; | ||
| 26 | char *strtab; | ||
| 27 | }; | ||
| 28 | static struct section *secs; | ||
| 29 | |||
| 30 | /* | ||
| 31 | * Following symbols have been audited. There values are constant and do | ||
| 32 | * not change if bzImage is loaded at a different physical address than | ||
| 33 | * the address for which it has been compiled. Don't warn user about | ||
| 34 | * absolute relocations present w.r.t these symbols. | ||
| 35 | */ | ||
| 36 | static const char abs_sym_regex[] = | ||
| 37 | "^(xen_irq_disable_direct_reloc$|" | ||
| 38 | "xen_save_fl_direct_reloc$|" | ||
| 39 | "VDSO|" | ||
| 40 | "__crc_)"; | ||
| 41 | static regex_t abs_sym_regex_c; | ||
| 42 | static int is_abs_reloc(const char *sym_name) | ||
| 43 | { | ||
| 44 | return !regexec(&abs_sym_regex_c, sym_name, 0, NULL, 0); | ||
| 45 | } | ||
| 46 | |||
| 47 | /* | ||
| 48 | * These symbols are known to be relative, even if the linker marks them | ||
| 49 | * as absolute (typically defined outside any section in the linker script.) | ||
| 50 | */ | ||
| 51 | static const char rel_sym_regex[] = | ||
| 52 | "^_end$"; | ||
| 53 | static regex_t rel_sym_regex_c; | ||
| 54 | static int is_rel_reloc(const char *sym_name) | ||
| 55 | { | ||
| 56 | return !regexec(&rel_sym_regex_c, sym_name, 0, NULL, 0); | ||
| 57 | } | ||
| 58 | |||
| 59 | static void regex_init(void) | ||
| 60 | { | ||
| 61 | char errbuf[128]; | ||
| 62 | int err; | ||
| 63 | |||
| 64 | err = regcomp(&abs_sym_regex_c, abs_sym_regex, | ||
| 65 | REG_EXTENDED|REG_NOSUB); | ||
| 66 | if (err) { | ||
| 67 | regerror(err, &abs_sym_regex_c, errbuf, sizeof errbuf); | ||
| 68 | die("%s", errbuf); | ||
| 69 | } | ||
| 70 | |||
| 71 | err = regcomp(&rel_sym_regex_c, rel_sym_regex, | ||
| 72 | REG_EXTENDED|REG_NOSUB); | ||
| 73 | if (err) { | ||
| 74 | regerror(err, &rel_sym_regex_c, errbuf, sizeof errbuf); | ||
| 75 | die("%s", errbuf); | ||
| 76 | } | ||
| 77 | } | ||
| 78 | |||
| 79 | static void die(char *fmt, ...) | ||
| 80 | { | ||
| 81 | va_list ap; | ||
| 82 | va_start(ap, fmt); | ||
| 83 | vfprintf(stderr, fmt, ap); | ||
| 84 | va_end(ap); | ||
| 85 | exit(1); | ||
| 86 | } | ||
| 87 | |||
| 88 | static const char *sym_type(unsigned type) | ||
| 89 | { | ||
| 90 | static const char *type_name[] = { | ||
| 91 | #define SYM_TYPE(X) [X] = #X | ||
| 92 | SYM_TYPE(STT_NOTYPE), | ||
| 93 | SYM_TYPE(STT_OBJECT), | ||
| 94 | SYM_TYPE(STT_FUNC), | ||
| 95 | SYM_TYPE(STT_SECTION), | ||
| 96 | SYM_TYPE(STT_FILE), | ||
| 97 | SYM_TYPE(STT_COMMON), | ||
| 98 | SYM_TYPE(STT_TLS), | ||
| 99 | #undef SYM_TYPE | ||
| 100 | }; | ||
| 101 | const char *name = "unknown sym type name"; | ||
| 102 | if (type < ARRAY_SIZE(type_name)) { | ||
| 103 | name = type_name[type]; | ||
| 104 | } | ||
| 105 | return name; | ||
| 106 | } | ||
| 107 | |||
| 108 | static const char *sym_bind(unsigned bind) | ||
| 109 | { | ||
| 110 | static const char *bind_name[] = { | ||
| 111 | #define SYM_BIND(X) [X] = #X | ||
| 112 | SYM_BIND(STB_LOCAL), | ||
| 113 | SYM_BIND(STB_GLOBAL), | ||
| 114 | SYM_BIND(STB_WEAK), | ||
| 115 | #undef SYM_BIND | ||
| 116 | }; | ||
| 117 | const char *name = "unknown sym bind name"; | ||
| 118 | if (bind < ARRAY_SIZE(bind_name)) { | ||
| 119 | name = bind_name[bind]; | ||
| 120 | } | ||
| 121 | return name; | ||
| 122 | } | ||
| 123 | |||
| 124 | static const char *sym_visibility(unsigned visibility) | ||
| 125 | { | ||
| 126 | static const char *visibility_name[] = { | ||
| 127 | #define SYM_VISIBILITY(X) [X] = #X | ||
| 128 | SYM_VISIBILITY(STV_DEFAULT), | ||
| 129 | SYM_VISIBILITY(STV_INTERNAL), | ||
| 130 | SYM_VISIBILITY(STV_HIDDEN), | ||
| 131 | SYM_VISIBILITY(STV_PROTECTED), | ||
| 132 | #undef SYM_VISIBILITY | ||
| 133 | }; | ||
| 134 | const char *name = "unknown sym visibility name"; | ||
| 135 | if (visibility < ARRAY_SIZE(visibility_name)) { | ||
| 136 | name = visibility_name[visibility]; | ||
| 137 | } | ||
| 138 | return name; | ||
| 139 | } | ||
| 140 | |||
| 141 | static const char *rel_type(unsigned type) | ||
| 142 | { | ||
| 143 | static const char *type_name[] = { | ||
| 144 | #define REL_TYPE(X) [X] = #X | ||
| 145 | REL_TYPE(R_386_NONE), | ||
| 146 | REL_TYPE(R_386_32), | ||
| 147 | REL_TYPE(R_386_PC32), | ||
| 148 | REL_TYPE(R_386_GOT32), | ||
| 149 | REL_TYPE(R_386_PLT32), | ||
| 150 | REL_TYPE(R_386_COPY), | ||
| 151 | REL_TYPE(R_386_GLOB_DAT), | ||
| 152 | REL_TYPE(R_386_JMP_SLOT), | ||
| 153 | REL_TYPE(R_386_RELATIVE), | ||
| 154 | REL_TYPE(R_386_GOTOFF), | ||
| 155 | REL_TYPE(R_386_GOTPC), | ||
| 156 | #undef REL_TYPE | ||
| 157 | }; | ||
| 158 | const char *name = "unknown type rel type name"; | ||
| 159 | if (type < ARRAY_SIZE(type_name) && type_name[type]) { | ||
| 160 | name = type_name[type]; | ||
| 161 | } | ||
| 162 | return name; | ||
| 163 | } | ||
| 164 | |||
| 165 | static const char *sec_name(unsigned shndx) | ||
| 166 | { | ||
| 167 | const char *sec_strtab; | ||
| 168 | const char *name; | ||
| 169 | sec_strtab = secs[ehdr.e_shstrndx].strtab; | ||
| 170 | name = "<noname>"; | ||
| 171 | if (shndx < ehdr.e_shnum) { | ||
| 172 | name = sec_strtab + secs[shndx].shdr.sh_name; | ||
| 173 | } | ||
| 174 | else if (shndx == SHN_ABS) { | ||
| 175 | name = "ABSOLUTE"; | ||
| 176 | } | ||
| 177 | else if (shndx == SHN_COMMON) { | ||
| 178 | name = "COMMON"; | ||
| 179 | } | ||
| 180 | return name; | ||
| 181 | } | ||
| 182 | |||
| 183 | static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym) | ||
| 184 | { | ||
| 185 | const char *name; | ||
| 186 | name = "<noname>"; | ||
| 187 | if (sym->st_name) { | ||
| 188 | name = sym_strtab + sym->st_name; | ||
| 189 | } | ||
| 190 | else { | ||
| 191 | name = sec_name(secs[sym->st_shndx].shdr.sh_name); | ||
| 192 | } | ||
| 193 | return name; | ||
| 194 | } | ||
| 195 | |||
| 196 | |||
| 197 | |||
| 198 | #if BYTE_ORDER == LITTLE_ENDIAN | ||
| 199 | #define le16_to_cpu(val) (val) | ||
| 200 | #define le32_to_cpu(val) (val) | ||
| 201 | #endif | ||
| 202 | #if BYTE_ORDER == BIG_ENDIAN | ||
| 203 | #define le16_to_cpu(val) bswap_16(val) | ||
| 204 | #define le32_to_cpu(val) bswap_32(val) | ||
| 205 | #endif | ||
| 206 | |||
| 207 | static uint16_t elf16_to_cpu(uint16_t val) | ||
| 208 | { | ||
| 209 | return le16_to_cpu(val); | ||
| 210 | } | ||
| 211 | |||
| 212 | static uint32_t elf32_to_cpu(uint32_t val) | ||
| 213 | { | ||
| 214 | return le32_to_cpu(val); | ||
| 215 | } | ||
| 216 | |||
| 217 | static void read_ehdr(FILE *fp) | ||
| 218 | { | ||
| 219 | if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) { | ||
| 220 | die("Cannot read ELF header: %s\n", | ||
| 221 | strerror(errno)); | ||
| 222 | } | ||
| 223 | if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) { | ||
| 224 | die("No ELF magic\n"); | ||
| 225 | } | ||
| 226 | if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) { | ||
| 227 | die("Not a 32 bit executable\n"); | ||
| 228 | } | ||
| 229 | if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) { | ||
| 230 | die("Not a LSB ELF executable\n"); | ||
| 231 | } | ||
| 232 | if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) { | ||
| 233 | die("Unknown ELF version\n"); | ||
| 234 | } | ||
| 235 | /* Convert the fields to native endian */ | ||
| 236 | ehdr.e_type = elf16_to_cpu(ehdr.e_type); | ||
| 237 | ehdr.e_machine = elf16_to_cpu(ehdr.e_machine); | ||
| 238 | ehdr.e_version = elf32_to_cpu(ehdr.e_version); | ||
| 239 | ehdr.e_entry = elf32_to_cpu(ehdr.e_entry); | ||
| 240 | ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff); | ||
| 241 | ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff); | ||
| 242 | ehdr.e_flags = elf32_to_cpu(ehdr.e_flags); | ||
| 243 | ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize); | ||
| 244 | ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize); | ||
| 245 | ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum); | ||
| 246 | ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize); | ||
| 247 | ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum); | ||
| 248 | ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx); | ||
| 249 | |||
| 250 | if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) { | ||
| 251 | die("Unsupported ELF header type\n"); | ||
| 252 | } | ||
| 253 | if (ehdr.e_machine != EM_386) { | ||
| 254 | die("Not for x86\n"); | ||
| 255 | } | ||
| 256 | if (ehdr.e_version != EV_CURRENT) { | ||
| 257 | die("Unknown ELF version\n"); | ||
| 258 | } | ||
| 259 | if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) { | ||
| 260 | die("Bad Elf header size\n"); | ||
| 261 | } | ||
| 262 | if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) { | ||
| 263 | die("Bad program header entry\n"); | ||
| 264 | } | ||
| 265 | if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) { | ||
| 266 | die("Bad section header entry\n"); | ||
| 267 | } | ||
| 268 | if (ehdr.e_shstrndx >= ehdr.e_shnum) { | ||
| 269 | die("String table index out of bounds\n"); | ||
| 270 | } | ||
| 271 | } | ||
| 272 | |||
| 273 | static void read_shdrs(FILE *fp) | ||
| 274 | { | ||
| 275 | int i; | ||
| 276 | Elf32_Shdr shdr; | ||
| 277 | |||
| 278 | secs = calloc(ehdr.e_shnum, sizeof(struct section)); | ||
| 279 | if (!secs) { | ||
| 280 | die("Unable to allocate %d section headers\n", | ||
| 281 | ehdr.e_shnum); | ||
| 282 | } | ||
| 283 | if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) { | ||
| 284 | die("Seek to %d failed: %s\n", | ||
| 285 | ehdr.e_shoff, strerror(errno)); | ||
| 286 | } | ||
| 287 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 288 | struct section *sec = &secs[i]; | ||
| 289 | if (fread(&shdr, sizeof shdr, 1, fp) != 1) | ||
| 290 | die("Cannot read ELF section headers %d/%d: %s\n", | ||
| 291 | i, ehdr.e_shnum, strerror(errno)); | ||
| 292 | sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name); | ||
| 293 | sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type); | ||
| 294 | sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags); | ||
| 295 | sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr); | ||
| 296 | sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset); | ||
| 297 | sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size); | ||
| 298 | sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link); | ||
| 299 | sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info); | ||
| 300 | sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign); | ||
| 301 | sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize); | ||
| 302 | if (sec->shdr.sh_link < ehdr.e_shnum) | ||
| 303 | sec->link = &secs[sec->shdr.sh_link]; | ||
| 304 | } | ||
| 305 | |||
| 306 | } | ||
| 307 | |||
| 308 | static void read_strtabs(FILE *fp) | ||
| 309 | { | ||
| 310 | int i; | ||
| 311 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 312 | struct section *sec = &secs[i]; | ||
| 313 | if (sec->shdr.sh_type != SHT_STRTAB) { | ||
| 314 | continue; | ||
| 315 | } | ||
| 316 | sec->strtab = malloc(sec->shdr.sh_size); | ||
| 317 | if (!sec->strtab) { | ||
| 318 | die("malloc of %d bytes for strtab failed\n", | ||
| 319 | sec->shdr.sh_size); | ||
| 320 | } | ||
| 321 | if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { | ||
| 322 | die("Seek to %d failed: %s\n", | ||
| 323 | sec->shdr.sh_offset, strerror(errno)); | ||
| 324 | } | ||
| 325 | if (fread(sec->strtab, 1, sec->shdr.sh_size, fp) | ||
| 326 | != sec->shdr.sh_size) { | ||
| 327 | die("Cannot read symbol table: %s\n", | ||
| 328 | strerror(errno)); | ||
| 329 | } | ||
| 330 | } | ||
| 331 | } | ||
| 332 | |||
| 333 | static void read_symtabs(FILE *fp) | ||
| 334 | { | ||
| 335 | int i,j; | ||
| 336 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 337 | struct section *sec = &secs[i]; | ||
| 338 | if (sec->shdr.sh_type != SHT_SYMTAB) { | ||
| 339 | continue; | ||
| 340 | } | ||
| 341 | sec->symtab = malloc(sec->shdr.sh_size); | ||
| 342 | if (!sec->symtab) { | ||
| 343 | die("malloc of %d bytes for symtab failed\n", | ||
| 344 | sec->shdr.sh_size); | ||
| 345 | } | ||
| 346 | if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { | ||
| 347 | die("Seek to %d failed: %s\n", | ||
| 348 | sec->shdr.sh_offset, strerror(errno)); | ||
| 349 | } | ||
| 350 | if (fread(sec->symtab, 1, sec->shdr.sh_size, fp) | ||
| 351 | != sec->shdr.sh_size) { | ||
| 352 | die("Cannot read symbol table: %s\n", | ||
| 353 | strerror(errno)); | ||
| 354 | } | ||
| 355 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) { | ||
| 356 | Elf32_Sym *sym = &sec->symtab[j]; | ||
| 357 | sym->st_name = elf32_to_cpu(sym->st_name); | ||
| 358 | sym->st_value = elf32_to_cpu(sym->st_value); | ||
| 359 | sym->st_size = elf32_to_cpu(sym->st_size); | ||
| 360 | sym->st_shndx = elf16_to_cpu(sym->st_shndx); | ||
| 361 | } | ||
| 362 | } | ||
| 363 | } | ||
| 364 | |||
| 365 | |||
| 366 | static void read_relocs(FILE *fp) | ||
| 367 | { | ||
| 368 | int i,j; | ||
| 369 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 370 | struct section *sec = &secs[i]; | ||
| 371 | if (sec->shdr.sh_type != SHT_REL) { | ||
| 372 | continue; | ||
| 373 | } | ||
| 374 | sec->reltab = malloc(sec->shdr.sh_size); | ||
| 375 | if (!sec->reltab) { | ||
| 376 | die("malloc of %d bytes for relocs failed\n", | ||
| 377 | sec->shdr.sh_size); | ||
| 378 | } | ||
| 379 | if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) { | ||
| 380 | die("Seek to %d failed: %s\n", | ||
| 381 | sec->shdr.sh_offset, strerror(errno)); | ||
| 382 | } | ||
| 383 | if (fread(sec->reltab, 1, sec->shdr.sh_size, fp) | ||
| 384 | != sec->shdr.sh_size) { | ||
| 385 | die("Cannot read symbol table: %s\n", | ||
| 386 | strerror(errno)); | ||
| 387 | } | ||
| 388 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { | ||
| 389 | Elf32_Rel *rel = &sec->reltab[j]; | ||
| 390 | rel->r_offset = elf32_to_cpu(rel->r_offset); | ||
| 391 | rel->r_info = elf32_to_cpu(rel->r_info); | ||
| 392 | } | ||
| 393 | } | ||
| 394 | } | ||
| 395 | |||
| 396 | |||
| 397 | static void print_absolute_symbols(void) | ||
| 398 | { | ||
| 399 | int i; | ||
| 400 | printf("Absolute symbols\n"); | ||
| 401 | printf(" Num: Value Size Type Bind Visibility Name\n"); | ||
| 402 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 403 | struct section *sec = &secs[i]; | ||
| 404 | char *sym_strtab; | ||
| 405 | Elf32_Sym *sh_symtab; | ||
| 406 | int j; | ||
| 407 | |||
| 408 | if (sec->shdr.sh_type != SHT_SYMTAB) { | ||
| 409 | continue; | ||
| 410 | } | ||
| 411 | sh_symtab = sec->symtab; | ||
| 412 | sym_strtab = sec->link->strtab; | ||
| 413 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) { | ||
| 414 | Elf32_Sym *sym; | ||
| 415 | const char *name; | ||
| 416 | sym = &sec->symtab[j]; | ||
| 417 | name = sym_name(sym_strtab, sym); | ||
| 418 | if (sym->st_shndx != SHN_ABS) { | ||
| 419 | continue; | ||
| 420 | } | ||
| 421 | printf("%5d %08x %5d %10s %10s %12s %s\n", | ||
| 422 | j, sym->st_value, sym->st_size, | ||
| 423 | sym_type(ELF32_ST_TYPE(sym->st_info)), | ||
| 424 | sym_bind(ELF32_ST_BIND(sym->st_info)), | ||
| 425 | sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)), | ||
| 426 | name); | ||
| 427 | } | ||
| 428 | } | ||
| 429 | printf("\n"); | ||
| 430 | } | ||
| 431 | |||
| 432 | static void print_absolute_relocs(void) | ||
| 433 | { | ||
| 434 | int i, printed = 0; | ||
| 435 | |||
| 436 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 437 | struct section *sec = &secs[i]; | ||
| 438 | struct section *sec_applies, *sec_symtab; | ||
| 439 | char *sym_strtab; | ||
| 440 | Elf32_Sym *sh_symtab; | ||
| 441 | int j; | ||
| 442 | if (sec->shdr.sh_type != SHT_REL) { | ||
| 443 | continue; | ||
| 444 | } | ||
| 445 | sec_symtab = sec->link; | ||
| 446 | sec_applies = &secs[sec->shdr.sh_info]; | ||
| 447 | if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) { | ||
| 448 | continue; | ||
| 449 | } | ||
| 450 | sh_symtab = sec_symtab->symtab; | ||
| 451 | sym_strtab = sec_symtab->link->strtab; | ||
| 452 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { | ||
| 453 | Elf32_Rel *rel; | ||
| 454 | Elf32_Sym *sym; | ||
| 455 | const char *name; | ||
| 456 | rel = &sec->reltab[j]; | ||
| 457 | sym = &sh_symtab[ELF32_R_SYM(rel->r_info)]; | ||
| 458 | name = sym_name(sym_strtab, sym); | ||
| 459 | if (sym->st_shndx != SHN_ABS) { | ||
| 460 | continue; | ||
| 461 | } | ||
| 462 | |||
| 463 | /* Absolute symbols are not relocated if bzImage is | ||
| 464 | * loaded at a non-compiled address. Display a warning | ||
| 465 | * to user at compile time about the absolute | ||
| 466 | * relocations present. | ||
| 467 | * | ||
| 468 | * User need to audit the code to make sure | ||
| 469 | * some symbols which should have been section | ||
| 470 | * relative have not become absolute because of some | ||
| 471 | * linker optimization or wrong programming usage. | ||
| 472 | * | ||
| 473 | * Before warning check if this absolute symbol | ||
| 474 | * relocation is harmless. | ||
| 475 | */ | ||
| 476 | if (is_abs_reloc(name) || is_rel_reloc(name)) | ||
| 477 | continue; | ||
| 478 | |||
| 479 | if (!printed) { | ||
| 480 | printf("WARNING: Absolute relocations" | ||
| 481 | " present\n"); | ||
| 482 | printf("Offset Info Type Sym.Value " | ||
| 483 | "Sym.Name\n"); | ||
| 484 | printed = 1; | ||
| 485 | } | ||
| 486 | |||
| 487 | printf("%08x %08x %10s %08x %s\n", | ||
| 488 | rel->r_offset, | ||
| 489 | rel->r_info, | ||
| 490 | rel_type(ELF32_R_TYPE(rel->r_info)), | ||
| 491 | sym->st_value, | ||
| 492 | name); | ||
| 493 | } | ||
| 494 | } | ||
| 495 | |||
| 496 | if (printed) | ||
| 497 | printf("\n"); | ||
| 498 | } | ||
| 499 | |||
| 500 | static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym)) | ||
| 501 | { | ||
| 502 | int i; | ||
| 503 | /* Walk through the relocations */ | ||
| 504 | for (i = 0; i < ehdr.e_shnum; i++) { | ||
| 505 | char *sym_strtab; | ||
| 506 | Elf32_Sym *sh_symtab; | ||
| 507 | struct section *sec_applies, *sec_symtab; | ||
| 508 | int j; | ||
| 509 | struct section *sec = &secs[i]; | ||
| 510 | |||
| 511 | if (sec->shdr.sh_type != SHT_REL) { | ||
| 512 | continue; | ||
| 513 | } | ||
| 514 | sec_symtab = sec->link; | ||
| 515 | sec_applies = &secs[sec->shdr.sh_info]; | ||
| 516 | if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) { | ||
| 517 | continue; | ||
| 518 | } | ||
| 519 | sh_symtab = sec_symtab->symtab; | ||
| 520 | sym_strtab = sec_symtab->link->strtab; | ||
| 521 | for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) { | ||
| 522 | Elf32_Rel *rel; | ||
| 523 | Elf32_Sym *sym; | ||
| 524 | unsigned r_type; | ||
| 525 | rel = &sec->reltab[j]; | ||
| 526 | sym = &sh_symtab[ELF32_R_SYM(rel->r_info)]; | ||
| 527 | r_type = ELF32_R_TYPE(rel->r_info); | ||
| 528 | /* Don't visit relocations to absolute symbols */ | ||
| 529 | if (sym->st_shndx == SHN_ABS && | ||
| 530 | !is_rel_reloc(sym_name(sym_strtab, sym))) { | ||
| 531 | continue; | ||
| 532 | } | ||
| 533 | switch (r_type) { | ||
| 534 | case R_386_NONE: | ||
| 535 | case R_386_PC32: | ||
| 536 | /* | ||
| 537 | * NONE can be ignored and and PC relative | ||
| 538 | * relocations don't need to be adjusted. | ||
| 539 | */ | ||
| 540 | break; | ||
| 541 | case R_386_32: | ||
| 542 | /* Visit relocations that need to be adjusted */ | ||
| 543 | visit(rel, sym); | ||
| 544 | break; | ||
| 545 | default: | ||
| 546 | die("Unsupported relocation type: %s (%d)\n", | ||
| 547 | rel_type(r_type), r_type); | ||
| 548 | break; | ||
| 549 | } | ||
| 550 | } | ||
| 551 | } | ||
| 552 | } | ||
| 553 | |||
| 554 | static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym) | ||
| 555 | { | ||
| 556 | reloc_count += 1; | ||
| 557 | } | ||
| 558 | |||
| 559 | static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym) | ||
| 560 | { | ||
| 561 | /* Remember the address that needs to be adjusted. */ | ||
| 562 | relocs[reloc_idx++] = rel->r_offset; | ||
| 563 | } | ||
| 564 | |||
| 565 | static int cmp_relocs(const void *va, const void *vb) | ||
| 566 | { | ||
| 567 | const unsigned long *a, *b; | ||
| 568 | a = va; b = vb; | ||
| 569 | return (*a == *b)? 0 : (*a > *b)? 1 : -1; | ||
| 570 | } | ||
| 571 | |||
| 572 | static void emit_relocs(int as_text) | ||
| 573 | { | ||
| 574 | int i; | ||
| 575 | /* Count how many relocations I have and allocate space for them. */ | ||
| 576 | reloc_count = 0; | ||
| 577 | walk_relocs(count_reloc); | ||
| 578 | relocs = malloc(reloc_count * sizeof(relocs[0])); | ||
| 579 | if (!relocs) { | ||
| 580 | die("malloc of %d entries for relocs failed\n", | ||
| 581 | reloc_count); | ||
| 582 | } | ||
| 583 | /* Collect up the relocations */ | ||
| 584 | reloc_idx = 0; | ||
| 585 | walk_relocs(collect_reloc); | ||
| 586 | |||
| 587 | /* Order the relocations for more efficient processing */ | ||
| 588 | qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs); | ||
| 589 | |||
| 590 | /* Print the relocations */ | ||
| 591 | if (as_text) { | ||
| 592 | /* Print the relocations in a form suitable that | ||
| 593 | * gas will like. | ||
| 594 | */ | ||
| 595 | printf(".section \".data.reloc\",\"a\"\n"); | ||
| 596 | printf(".balign 4\n"); | ||
| 597 | for (i = 0; i < reloc_count; i++) { | ||
| 598 | printf("\t .long 0x%08lx\n", relocs[i]); | ||
| 599 | } | ||
| 600 | printf("\n"); | ||
| 601 | } | ||
| 602 | else { | ||
| 603 | unsigned char buf[4]; | ||
| 604 | /* Print a stop */ | ||
| 605 | fwrite("\0\0\0\0", 4, 1, stdout); | ||
| 606 | /* Now print each relocation */ | ||
| 607 | for (i = 0; i < reloc_count; i++) { | ||
| 608 | buf[0] = (relocs[i] >> 0) & 0xff; | ||
| 609 | buf[1] = (relocs[i] >> 8) & 0xff; | ||
| 610 | buf[2] = (relocs[i] >> 16) & 0xff; | ||
| 611 | buf[3] = (relocs[i] >> 24) & 0xff; | ||
| 612 | fwrite(buf, 4, 1, stdout); | ||
| 613 | } | ||
| 614 | } | ||
| 615 | } | ||
| 616 | |||
| 617 | static void usage(void) | ||
| 618 | { | ||
| 619 | die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n"); | ||
| 620 | } | ||
| 621 | |||
| 622 | int main(int argc, char **argv) | ||
| 623 | { | ||
| 624 | int show_absolute_syms, show_absolute_relocs; | ||
| 625 | int as_text; | ||
| 626 | const char *fname; | ||
| 627 | FILE *fp; | ||
| 628 | int i; | ||
| 629 | |||
| 630 | regex_init(); | ||
| 631 | |||
| 632 | show_absolute_syms = 0; | ||
| 633 | show_absolute_relocs = 0; | ||
| 634 | as_text = 0; | ||
| 635 | fname = NULL; | ||
| 636 | for (i = 1; i < argc; i++) { | ||
| 637 | char *arg = argv[i]; | ||
| 638 | if (*arg == '-') { | ||
| 639 | if (strcmp(argv[1], "--abs-syms") == 0) { | ||
| 640 | show_absolute_syms = 1; | ||
| 641 | continue; | ||
| 642 | } | ||
| 643 | |||
| 644 | if (strcmp(argv[1], "--abs-relocs") == 0) { | ||
| 645 | show_absolute_relocs = 1; | ||
| 646 | continue; | ||
| 647 | } | ||
| 648 | else if (strcmp(argv[1], "--text") == 0) { | ||
| 649 | as_text = 1; | ||
| 650 | continue; | ||
| 651 | } | ||
| 652 | } | ||
| 653 | else if (!fname) { | ||
| 654 | fname = arg; | ||
| 655 | continue; | ||
| 656 | } | ||
| 657 | usage(); | ||
| 658 | } | ||
| 659 | if (!fname) { | ||
| 660 | usage(); | ||
| 661 | } | ||
| 662 | fp = fopen(fname, "r"); | ||
| 663 | if (!fp) { | ||
| 664 | die("Cannot open %s: %s\n", | ||
| 665 | fname, strerror(errno)); | ||
| 666 | } | ||
| 667 | read_ehdr(fp); | ||
| 668 | read_shdrs(fp); | ||
| 669 | read_strtabs(fp); | ||
| 670 | read_symtabs(fp); | ||
| 671 | read_relocs(fp); | ||
| 672 | if (show_absolute_syms) { | ||
| 673 | print_absolute_symbols(); | ||
| 674 | return 0; | ||
| 675 | } | ||
| 676 | if (show_absolute_relocs) { | ||
| 677 | print_absolute_relocs(); | ||
| 678 | return 0; | ||
| 679 | } | ||
| 680 | emit_relocs(as_text); | ||
| 681 | return 0; | ||
| 682 | } | ||
