arch/x86/tools/relocs.c

   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 static unsigned long reloc16_count, reloc16_idx;
  21 static unsigned long *relocs16;
  22
  23 struct section {
  24         Elf32_Shdr     shdr;
  25         struct section *link;
  26         Elf32_Sym      *symtab;
  27         Elf32_Rel      *reltab;
  28         char           *strtab;
  29 };
  30 static struct section *secs;
  31
  32 enum symtype {
  33         S_ABS,
  34         S_REL,
  35         S_SEG,
  36         S_LIN,
  37         S_NSYMTYPES
  38 };
  39
  40 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  41 /*
  42  * Following symbols have been audited. There values are constant and do
  43  * not change if bzImage is loaded at a different physical address than
  44  * the address for which it has been compiled. Don't warn user about
  45  * absolute relocations present w.r.t these symbols.
  46  */
  47         [S_ABS] =
  48         "^(xen_irq_disable_direct_reloc$|"
  49         "xen_save_fl_direct_reloc$|"
  50         "VDSO|"
  51         "__crc_)",
  52
  53 /*
  54  * These symbols are known to be relative, even if the linker marks them
  55  * as absolute (typically defined outside any section in the linker script.)
  56  */
  57         [S_REL] =
  58         "^_end$",
  59 };
  60
  61
  62 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  63 /*
  64  * These are 16-bit segment symbols when compiling 16-bit code.
  65  */
  66         [S_SEG] =
  67         "^real_mode_seg$",
  68
  69 /*
  70  * These are offsets belonging to segments, as opposed to linear addresses,
  71  * when compiling 16-bit code.
  72  */
  73         [S_LIN] =
  74         "^pa_",
  75 };
  76
  77 static const char * const *sym_regex;
  78
  79 static regex_t sym_regex_c[S_NSYMTYPES];
  80 static int is_reloc(enum symtype type, const char *sym_name)
  81 {
  82         return sym_regex[type] &&
  83                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
  84 }
  85
  86 static void regex_init(int use_real_mode)
  87 {
  88         char errbuf[128];
  89         int err;
  90         int i;
  91
  92         if (use_real_mode)
  93                 sym_regex = sym_regex_realmode;
  94         else
  95                 sym_regex = sym_regex_kernel;
  96
  97         for (i = 0; i < S_NSYMTYPES; i++) {
  98                 if (!sym_regex[i])
  99                         continue;
 100
 101                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 102                               REG_EXTENDED|REG_NOSUB);
 103
 104                 if (err) {
 105                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 106                         die("%s", errbuf);
 107                 }
 108         }
 109 }
 110
 111 static void die(char *fmt, ...)
 112 {
 113         va_list ap;
 114         va_start(ap, fmt);
 115         vfprintf(stderr, fmt, ap);
 116         va_end(ap);
 117         exit(1);
 118 }
 119
 120 static const char *sym_type(unsigned type)
 121 {
 122         static const char *type_name[] = {
 123 #define SYM_TYPE(X) [X] = #X
 124                 SYM_TYPE(STT_NOTYPE),
 125                 SYM_TYPE(STT_OBJECT),
 126                 SYM_TYPE(STT_FUNC),
 127                 SYM_TYPE(STT_SECTION),
 128                 SYM_TYPE(STT_FILE),
 129                 SYM_TYPE(STT_COMMON),
 130                 SYM_TYPE(STT_TLS),
 131 #undef SYM_TYPE
 132         };
 133         const char *name = "unknown sym type name";
 134         if (type < ARRAY_SIZE(type_name)) {
 135                 name = type_name[type];
 136         }
 137         return name;
 138 }
 139
 140 static const char *sym_bind(unsigned bind)
 141 {
 142         static const char *bind_name[] = {
 143 #define SYM_BIND(X) [X] = #X
 144                 SYM_BIND(STB_LOCAL),
 145                 SYM_BIND(STB_GLOBAL),
 146                 SYM_BIND(STB_WEAK),
 147 #undef SYM_BIND
 148         };
 149         const char *name = "unknown sym bind name";
 150         if (bind < ARRAY_SIZE(bind_name)) {
 151                 name = bind_name[bind];
 152         }
 153         return name;
 154 }
 155
 156 static const char *sym_visibility(unsigned visibility)
 157 {
 158         static const char *visibility_name[] = {
 159 #define SYM_VISIBILITY(X) [X] = #X
 160                 SYM_VISIBILITY(STV_DEFAULT),
 161                 SYM_VISIBILITY(STV_INTERNAL),
 162                 SYM_VISIBILITY(STV_HIDDEN),
 163                 SYM_VISIBILITY(STV_PROTECTED),
 164 #undef SYM_VISIBILITY
 165         };
 166         const char *name = "unknown sym visibility name";
 167         if (visibility < ARRAY_SIZE(visibility_name)) {
 168                 name = visibility_name[visibility];
 169         }
 170         return name;
 171 }
 172
 173 static const char *rel_type(unsigned type)
 174 {
 175         static const char *type_name[] = {
 176 #define REL_TYPE(X) [X] = #X
 177                 REL_TYPE(R_386_NONE),
 178                 REL_TYPE(R_386_32),
 179                 REL_TYPE(R_386_PC32),
 180                 REL_TYPE(R_386_GOT32),
 181                 REL_TYPE(R_386_PLT32),
 182                 REL_TYPE(R_386_COPY),
 183                 REL_TYPE(R_386_GLOB_DAT),
 184                 REL_TYPE(R_386_JMP_SLOT),
 185                 REL_TYPE(R_386_RELATIVE),
 186                 REL_TYPE(R_386_GOTOFF),
 187                 REL_TYPE(R_386_GOTPC),
 188                 REL_TYPE(R_386_8),
 189                 REL_TYPE(R_386_PC8),
 190                 REL_TYPE(R_386_16),
 191                 REL_TYPE(R_386_PC16),
 192 #undef REL_TYPE
 193         };
 194         const char *name = "unknown type rel type name";
 195         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 196                 name = type_name[type];
 197         }
 198         return name;
 199 }
 200
 201 static const char *sec_name(unsigned shndx)
 202 {
 203         const char *sec_strtab;
 204         const char *name;
 205         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 206         name = "<noname>";
 207         if (shndx < ehdr.e_shnum) {
 208                 name = sec_strtab + secs[shndx].shdr.sh_name;
 209         }
 210         else if (shndx == SHN_ABS) {
 211                 name = "ABSOLUTE";
 212         }
 213         else if (shndx == SHN_COMMON) {
 214                 name = "COMMON";
 215         }
 216         return name;
 217 }
 218
 219 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 220 {
 221         const char *name;
 222         name = "<noname>";
 223         if (sym->st_name) {
 224                 name = sym_strtab + sym->st_name;
 225         }
 226         else {
 227                 name = sec_name(sym->st_shndx);
 228         }
 229         return name;
 230 }
 231
 232
 233
 234 #if BYTE_ORDER == LITTLE_ENDIAN
 235 #define le16_to_cpu(val) (val)
 236 #define le32_to_cpu(val) (val)
 237 #endif
 238 #if BYTE_ORDER == BIG_ENDIAN
 239 #define le16_to_cpu(val) bswap_16(val)
 240 #define le32_to_cpu(val) bswap_32(val)
 241 #endif
 242
 243 static uint16_t elf16_to_cpu(uint16_t val)
 244 {
 245         return le16_to_cpu(val);
 246 }
 247
 248 static uint32_t elf32_to_cpu(uint32_t val)
 249 {
 250         return le32_to_cpu(val);
 251 }
 252
 253 static void read_ehdr(FILE *fp)
 254 {
 255         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 256                 die("Cannot read ELF header: %s\n",
 257                         strerror(errno));
 258         }
 259         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 260                 die("No ELF magic\n");
 261         }
 262         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 263                 die("Not a 32 bit executable\n");
 264         }
 265         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 266                 die("Not a LSB ELF executable\n");
 267         }
 268         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 269                 die("Unknown ELF version\n");
 270         }
 271         /* Convert the fields to native endian */
 272         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 273         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 274         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 275         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 276         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 277         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 278         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 279         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 280         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 281         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 282         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 283         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 284         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 285
 286         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 287                 die("Unsupported ELF header type\n");
 288         }
 289         if (ehdr.e_machine != EM_386) {
 290                 die("Not for x86\n");
 291         }
 292         if (ehdr.e_version != EV_CURRENT) {
 293                 die("Unknown ELF version\n");
 294         }
 295         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 296                 die("Bad Elf header size\n");
 297         }
 298         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 299                 die("Bad program header entry\n");
 300         }
 301         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 302                 die("Bad section header entry\n");
 303         }
 304         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 305                 die("String table index out of bounds\n");
 306         }
 307 }
 308
 309 static void read_shdrs(FILE *fp)
 310 {
 311         int i;
 312         Elf32_Shdr shdr;
 313
 314         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 315         if (!secs) {
 316                 die("Unable to allocate %d section headers\n",
 317                     ehdr.e_shnum);
 318         }
 319         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 320                 die("Seek to %d failed: %s\n",
 321                         ehdr.e_shoff, strerror(errno));
 322         }
 323         for (i = 0; i < ehdr.e_shnum; i++) {
 324                 struct section *sec = &secs[i];
 325                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 326                         die("Cannot read ELF section headers %d/%d: %s\n",
 327                             i, ehdr.e_shnum, strerror(errno));
 328                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 329                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 330                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 331                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 332                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 333                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 334                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 335                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 336                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 337                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 338                 if (sec->shdr.sh_link < ehdr.e_shnum)
 339                         sec->link = &secs[sec->shdr.sh_link];
 340         }
 341
 342 }
 343
 344 static void read_strtabs(FILE *fp)
 345 {
 346         int i;
 347         for (i = 0; i < ehdr.e_shnum; i++) {
 348                 struct section *sec = &secs[i];
 349                 if (sec->shdr.sh_type != SHT_STRTAB) {
 350                         continue;
 351                 }
 352                 sec->strtab = malloc(sec->shdr.sh_size);
 353                 if (!sec->strtab) {
 354                         die("malloc of %d bytes for strtab failed\n",
 355                                 sec->shdr.sh_size);
 356                 }
 357                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 358                         die("Seek to %d failed: %s\n",
 359                                 sec->shdr.sh_offset, strerror(errno));
 360                 }
 361                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 362                     != sec->shdr.sh_size) {
 363                         die("Cannot read symbol table: %s\n",
 364                                 strerror(errno));
 365                 }
 366         }
 367 }
 368
 369 static void read_symtabs(FILE *fp)
 370 {
 371         int i,j;
 372         for (i = 0; i < ehdr.e_shnum; i++) {
 373                 struct section *sec = &secs[i];
 374                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 375                         continue;
 376                 }
 377                 sec->symtab = malloc(sec->shdr.sh_size);
 378                 if (!sec->symtab) {
 379                         die("malloc of %d bytes for symtab failed\n",
 380                                 sec->shdr.sh_size);
 381                 }
 382                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 383                         die("Seek to %d failed: %s\n",
 384                                 sec->shdr.sh_offset, strerror(errno));
 385                 }
 386                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 387                     != sec->shdr.sh_size) {
 388                         die("Cannot read symbol table: %s\n",
 389                                 strerror(errno));
 390                 }
 391                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 392                         Elf32_Sym *sym = &sec->symtab[j];
 393                         sym->st_name  = elf32_to_cpu(sym->st_name);
 394                         sym->st_value = elf32_to_cpu(sym->st_value);
 395                         sym->st_size  = elf32_to_cpu(sym->st_size);
 396                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 397                 }
 398         }
 399 }
 400
 401
 402 static void read_relocs(FILE *fp)
 403 {
 404         int i,j;
 405         for (i = 0; i < ehdr.e_shnum; i++) {
 406                 struct section *sec = &secs[i];
 407                 if (sec->shdr.sh_type != SHT_REL) {
 408                         continue;
 409                 }
 410                 sec->reltab = malloc(sec->shdr.sh_size);
 411                 if (!sec->reltab) {
 412                         die("malloc of %d bytes for relocs failed\n",
 413                                 sec->shdr.sh_size);
 414                 }
 415                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 416                         die("Seek to %d failed: %s\n",
 417                                 sec->shdr.sh_offset, strerror(errno));
 418                 }
 419                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 420                     != sec->shdr.sh_size) {
 421                         die("Cannot read symbol table: %s\n",
 422                                 strerror(errno));
 423                 }
 424                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 425                         Elf32_Rel *rel = &sec->reltab[j];
 426                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 427                         rel->r_info   = elf32_to_cpu(rel->r_info);
 428                 }
 429         }
 430 }
 431
 432
 433 static void print_absolute_symbols(void)
 434 {
 435         int i;
 436         printf("Absolute symbols\n");
 437         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 438         for (i = 0; i < ehdr.e_shnum; i++) {
 439                 struct section *sec = &secs[i];
 440                 char *sym_strtab;
 441                 int j;
 442
 443                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 444                         continue;
 445                 }
 446                 sym_strtab = sec->link->strtab;
 447                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 448                         Elf32_Sym *sym;
 449                         const char *name;
 450                         sym = &sec->symtab[j];
 451                         name = sym_name(sym_strtab, sym);
 452                         if (sym->st_shndx != SHN_ABS) {
 453                                 continue;
 454                         }
 455                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 456                                 j, sym->st_value, sym->st_size,
 457                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 458                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 459                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 460                                 name);
 461                 }
 462         }
 463         printf("\n");
 464 }
 465
 466 static void print_absolute_relocs(void)
 467 {
 468         int i, printed = 0;
 469
 470         for (i = 0; i < ehdr.e_shnum; i++) {
 471                 struct section *sec = &secs[i];
 472                 struct section *sec_applies, *sec_symtab;
 473                 char *sym_strtab;
 474                 Elf32_Sym *sh_symtab;
 475                 int j;
 476                 if (sec->shdr.sh_type != SHT_REL) {
 477                         continue;
 478                 }
 479                 sec_symtab  = sec->link;
 480                 sec_applies = &secs[sec->shdr.sh_info];
 481                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 482                         continue;
 483                 }
 484                 sh_symtab  = sec_symtab->symtab;
 485                 sym_strtab = sec_symtab->link->strtab;
 486                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 487                         Elf32_Rel *rel;
 488                         Elf32_Sym *sym;
 489                         const char *name;
 490                         rel = &sec->reltab[j];
 491                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 492                         name = sym_name(sym_strtab, sym);
 493                         if (sym->st_shndx != SHN_ABS) {
 494                                 continue;
 495                         }
 496
 497                         /* Absolute symbols are not relocated if bzImage is
 498                          * loaded at a non-compiled address. Display a warning
 499                          * to user at compile time about the absolute
 500                          * relocations present.
 501                          *
 502                          * User need to audit the code to make sure
 503                          * some symbols which should have been section
 504                          * relative have not become absolute because of some
 505                          * linker optimization or wrong programming usage.
 506                          *
 507                          * Before warning check if this absolute symbol
 508                          * relocation is harmless.
 509                          */
 510                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 511                                 continue;
 512
 513                         if (!printed) {
 514                                 printf("WARNING: Absolute relocations"
 515                                         " present\n");
 516                                 printf("Offset     Info     Type     Sym.Value "
 517                                         "Sym.Name\n");
 518                                 printed = 1;
 519                         }
 520
 521                         printf("%08x %08x %10s %08x  %s\n",
 522                                 rel->r_offset,
 523                                 rel->r_info,
 524                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 525                                 sym->st_value,
 526                                 name);
 527                 }
 528         }
 529
 530         if (printed)
 531                 printf("\n");
 532 }
 533
 534 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 535                         int use_real_mode)
 536 {
 537         int i;
 538         /* Walk through the relocations */
 539         for (i = 0; i < ehdr.e_shnum; i++) {
 540                 char *sym_strtab;
 541                 Elf32_Sym *sh_symtab;
 542                 struct section *sec_applies, *sec_symtab;
 543                 int j;
 544                 struct section *sec = &secs[i];
 545
 546                 if (sec->shdr.sh_type != SHT_REL) {
 547                         continue;
 548                 }
 549                 sec_symtab  = sec->link;
 550                 sec_applies = &secs[sec->shdr.sh_info];
 551                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 552                         continue;
 553                 }
 554                 sh_symtab = sec_symtab->symtab;
 555                 sym_strtab = sec_symtab->link->strtab;
 556                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 557                         Elf32_Rel *rel;
 558                         Elf32_Sym *sym;
 559                         unsigned r_type;
 560                         const char *symname;
 561                         rel = &sec->reltab[j];
 562                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 563                         r_type = ELF32_R_TYPE(rel->r_info);
 564
 565                         switch (r_type) {
 566                         case R_386_NONE:
 567                         case R_386_PC32:
 568                         case R_386_PC16:
 569                         case R_386_PC8:
 570                                 /*
 571                                  * NONE can be ignored and and PC relative
 572                                  * relocations don't need to be adjusted.
 573                                  */
 574                                 break;
 575
 576                         case R_386_16:
 577                                 symname = sym_name(sym_strtab, sym);
 578                                 if (!use_real_mode)
 579                                         goto bad;
 580                                 if (sym->st_shndx == SHN_ABS) {
 581                                         if (is_reloc(S_ABS, symname))
 582                                                 break;
 583                                         else if (!is_reloc(S_SEG, symname))
 584                                                 goto bad;
 585                                 } else {
 586                                         if (is_reloc(S_LIN, symname))
 587                                                 goto bad;
 588                                         else
 589                                                 break;
 590                                 }
 591                                 visit(rel, sym);
 592                                 break;
 593
 594                         case R_386_32:
 595                                 symname = sym_name(sym_strtab, sym);
 596                                 if (sym->st_shndx == SHN_ABS) {
 597                                         if (is_reloc(S_ABS, symname))
 598                                                 break;
 599                                         else if (!is_reloc(S_REL, symname))
 600                                                 goto bad;
 601                                 } else {
 602                                         if (use_real_mode &&
 603                                             !is_reloc(S_LIN, symname))
 604                                                 break;
 605                                 }
 606                                 visit(rel, sym);
 607                                 break;
 608                         default:
 609                                 die("Unsupported relocation type: %s (%d)\n",
 610                                     rel_type(r_type), r_type);
 611                                 break;
 612                         bad:
 613                                 symname = sym_name(sym_strtab, sym);
 614                                 die("Invalid %s relocation: %s\n",
 615                                     rel_type(r_type), symname);
 616                         }
 617                 }
 618         }
 619 }
 620
 621 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 622 {
 623         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 624                 reloc16_count++;
 625         else
 626                 reloc_count++;
 627 }
 628
 629 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 630 {
 631         /* Remember the address that needs to be adjusted. */
 632         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 633                 relocs16[reloc16_idx++] = rel->r_offset;
 634         else
 635                 relocs[reloc_idx++] = rel->r_offset;
 636 }
 637
 638 static int cmp_relocs(const void *va, const void *vb)
 639 {
 640         const unsigned long *a, *b;
 641         a = va; b = vb;
 642         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 643 }
 644
 645 static int write32(unsigned int v, FILE *f)
 646 {
 647         unsigned char buf[4];
 648
 649         buf[0] = (v >>  0) & 0xff;
 650         buf[1] = (v >>  8) & 0xff;
 651         buf[2] = (v >> 16) & 0xff;
 652         buf[3] = (v >> 24) & 0xff;
 653         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 654 }
 655
 656 static void emit_relocs(int as_text, int use_real_mode)
 657 {
 658         int i;
 659         /* Count how many relocations I have and allocate space for them. */
 660         reloc_count = 0;
 661         walk_relocs(count_reloc, use_real_mode);
 662         relocs = malloc(reloc_count * sizeof(relocs[0]));
 663         if (!relocs) {
 664                 die("malloc of %d entries for relocs failed\n",
 665                         reloc_count);
 666         }
 667
 668         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 669         if (!relocs16) {
 670                 die("malloc of %d entries for relocs16 failed\n",
 671                         reloc16_count);
 672         }
 673         /* Collect up the relocations */
 674         reloc_idx = 0;
 675         walk_relocs(collect_reloc, use_real_mode);
 676
 677         if (reloc16_count && !use_real_mode)
 678                 die("Segment relocations found but --realmode not specified\n");
 679
 680         /* Order the relocations for more efficient processing */
 681         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 682         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 683
 684         /* Print the relocations */
 685         if (as_text) {
 686                 /* Print the relocations in a form suitable that
 687                  * gas will like.
 688                  */
 689                 printf(".section \".data.reloc\",\"a\"\n");
 690                 printf(".balign 4\n");
 691                 if (use_real_mode) {
 692                         printf("\t.long %lu\n", reloc16_count);
 693                         for (i = 0; i < reloc16_count; i++)
 694                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 695                         printf("\t.long %lu\n", reloc_count);
 696                         for (i = 0; i < reloc_count; i++) {
 697                                 printf("\t.long 0x%08lx\n", relocs[i]);
 698                         }
 699                 } else {
 700                         /* Print a stop */
 701                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 702                         for (i = 0; i < reloc_count; i++) {
 703                                 printf("\t.long 0x%08lx\n", relocs[i]);
 704                         }
 705                 }
 706
 707                 printf("\n");
 708         }
 709         else {
 710                 if (use_real_mode) {
 711                         write32(reloc16_count, stdout);
 712                         for (i = 0; i < reloc16_count; i++)
 713                                 write32(relocs16[i], stdout);
 714                         write32(reloc_count, stdout);
 715
 716                         /* Now print each relocation */
 717                         for (i = 0; i < reloc_count; i++)
 718                                 write32(relocs[i], stdout);
 719                 } else {
 720                         /* Print a stop */
 721                         write32(0, stdout);
 722
 723                         /* Now print each relocation */
 724                         for (i = 0; i < reloc_count; i++) {
 725                                 write32(relocs[i], stdout);
 726                         }
 727                 }
 728         }
 729 }
 730
 731 static void usage(void)
 732 {
 733         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 734 }
 735
 736 int main(int argc, char **argv)
 737 {
 738         int show_absolute_syms, show_absolute_relocs;
 739         int as_text, use_real_mode;
 740         const char *fname;
 741         FILE *fp;
 742         int i;
 743
 744         show_absolute_syms = 0;
 745         show_absolute_relocs = 0;
 746         as_text = 0;
 747         use_real_mode = 0;
 748         fname = NULL;
 749         for (i = 1; i < argc; i++) {
 750                 char *arg = argv[i];
 751                 if (*arg == '-') {
 752                         if (strcmp(arg, "--abs-syms") == 0) {
 753                                 show_absolute_syms = 1;
 754                                 continue;
 755                         }
 756                         if (strcmp(arg, "--abs-relocs") == 0) {
 757                                 show_absolute_relocs = 1;
 758                                 continue;
 759                         }
 760                         if (strcmp(arg, "--text") == 0) {
 761                                 as_text = 1;
 762                                 continue;
 763                         }
 764                         if (strcmp(arg, "--realmode") == 0) {
 765                                 use_real_mode = 1;
 766                                 continue;
 767                         }
 768                 }
 769                 else if (!fname) {
 770                         fname = arg;
 771                         continue;
 772                 }
 773                 usage();
 774         }
 775         if (!fname) {
 776                 usage();
 777         }
 778         regex_init(use_real_mode);
 779         fp = fopen(fname, "r");
 780         if (!fp) {
 781                 die("Cannot open %s: %s\n",
 782                         fname, strerror(errno));
 783         }
 784         read_ehdr(fp);
 785         read_shdrs(fp);
 786         read_strtabs(fp);
 787         read_symtabs(fp);
 788         read_relocs(fp);
 789         if (show_absolute_syms) {
 790                 print_absolute_symbols();
 791                 return 0;
 792         }
 793         if (show_absolute_relocs) {
 794                 print_absolute_relocs();
 795                 return 0;
 796         }
 797         emit_relocs(as_text, use_real_mode);
 798         return 0;
 799 }