scripts/x86-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 #include <tools/le_byteshift.h>
  14
  15 static void die(char *fmt, ...);
  16
  17 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  18 static Elf32_Ehdr ehdr;
  19 static unsigned long reloc_count, reloc_idx;
  20 static unsigned long *relocs;
  21 static unsigned long reloc16_count, reloc16_idx;
  22 static unsigned long *relocs16;
  23
  24 struct section {
  25         Elf32_Shdr     shdr;
  26         struct section *link;
  27         Elf32_Sym      *symtab;
  28         Elf32_Rel      *reltab;
  29         char           *strtab;
  30 };
  31 static struct section *secs;
  32
  33 enum symtype {
  34         S_ABS,
  35         S_REL,
  36         S_SEG,
  37         S_LIN,
  38         S_NSYMTYPES
  39 };
  40
  41 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  42 /*
  43  * Following symbols have been audited. There values are constant and do
  44  * not change if bzImage is loaded at a different physical address than
  45  * the address for which it has been compiled. Don't warn user about
  46  * absolute relocations present w.r.t these symbols.
  47  */
  48         [S_ABS] =
  49         "^(xen_irq_disable_direct_reloc$|"
  50         "xen_save_fl_direct_reloc$|"
  51         "VDSO|"
  52         "__crc_)",
  53
  54 /*
  55  * These symbols are known to be relative, even if the linker marks them
  56  * as absolute (typically defined outside any section in the linker script.)
  57  */
  58         [S_REL] =
  59         "^_end$",
  60 };
  61
  62
  63 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  64 /*
  65  * These symbols are known to be relative, even if the linker marks them
  66  * as absolute (typically defined outside any section in the linker script.)
  67  */
  68         [S_REL] =
  69         "^pa_",
  70
  71 /*
  72  * These are 16-bit segment symbols when compiling 16-bit code.
  73  */
  74         [S_SEG] =
  75         "^real_mode_seg$",
  76
  77 /*
  78  * These are offsets belonging to segments, as opposed to linear addresses,
  79  * when compiling 16-bit code.
  80  */
  81         [S_LIN] =
  82         "^pa_",
  83 };
  84
  85 static const char * const *sym_regex;
  86
  87 static regex_t sym_regex_c[S_NSYMTYPES];
  88 static int is_reloc(enum symtype type, const char *sym_name)
  89 {
  90         return sym_regex[type] &&
  91                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
  92 }
  93
  94 static void regex_init(int use_real_mode)
  95 {
  96         char errbuf[128];
  97         int err;
  98         int i;
  99
 100         if (use_real_mode)
 101                 sym_regex = sym_regex_realmode;
 102         else
 103                 sym_regex = sym_regex_kernel;
 104
 105         for (i = 0; i < S_NSYMTYPES; i++) {
 106                 if (!sym_regex[i])
 107                         continue;
 108
 109                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 110                               REG_EXTENDED|REG_NOSUB);
 111
 112                 if (err) {
 113                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 114                         die("%s", errbuf);
 115                 }
 116         }
 117 }
 118
 119 static void die(char *fmt, ...)
 120 {
 121         va_list ap;
 122         va_start(ap, fmt);
 123         vfprintf(stderr, fmt, ap);
 124         va_end(ap);
 125         exit(1);
 126 }
 127
 128 static const char *sym_type(unsigned type)
 129 {
 130         static const char *type_name[] = {
 131 #define SYM_TYPE(X) [X] = #X
 132                 SYM_TYPE(STT_NOTYPE),
 133                 SYM_TYPE(STT_OBJECT),
 134                 SYM_TYPE(STT_FUNC),
 135                 SYM_TYPE(STT_SECTION),
 136                 SYM_TYPE(STT_FILE),
 137                 SYM_TYPE(STT_COMMON),
 138                 SYM_TYPE(STT_TLS),
 139 #undef SYM_TYPE
 140         };
 141         const char *name = "unknown sym type name";
 142         if (type < ARRAY_SIZE(type_name)) {
 143                 name = type_name[type];
 144         }
 145         return name;
 146 }
 147
 148 static const char *sym_bind(unsigned bind)
 149 {
 150         static const char *bind_name[] = {
 151 #define SYM_BIND(X) [X] = #X
 152                 SYM_BIND(STB_LOCAL),
 153                 SYM_BIND(STB_GLOBAL),
 154                 SYM_BIND(STB_WEAK),
 155 #undef SYM_BIND
 156         };
 157         const char *name = "unknown sym bind name";
 158         if (bind < ARRAY_SIZE(bind_name)) {
 159                 name = bind_name[bind];
 160         }
 161         return name;
 162 }
 163
 164 static const char *sym_visibility(unsigned visibility)
 165 {
 166         static const char *visibility_name[] = {
 167 #define SYM_VISIBILITY(X) [X] = #X
 168                 SYM_VISIBILITY(STV_DEFAULT),
 169                 SYM_VISIBILITY(STV_INTERNAL),
 170                 SYM_VISIBILITY(STV_HIDDEN),
 171                 SYM_VISIBILITY(STV_PROTECTED),
 172 #undef SYM_VISIBILITY
 173         };
 174         const char *name = "unknown sym visibility name";
 175         if (visibility < ARRAY_SIZE(visibility_name)) {
 176                 name = visibility_name[visibility];
 177         }
 178         return name;
 179 }
 180
 181 static const char *rel_type(unsigned type)
 182 {
 183         static const char *type_name[] = {
 184 #define REL_TYPE(X) [X] = #X
 185                 REL_TYPE(R_386_NONE),
 186                 REL_TYPE(R_386_32),
 187                 REL_TYPE(R_386_PC32),
 188                 REL_TYPE(R_386_GOT32),
 189                 REL_TYPE(R_386_PLT32),
 190                 REL_TYPE(R_386_COPY),
 191                 REL_TYPE(R_386_GLOB_DAT),
 192                 REL_TYPE(R_386_JMP_SLOT),
 193                 REL_TYPE(R_386_RELATIVE),
 194                 REL_TYPE(R_386_GOTOFF),
 195                 REL_TYPE(R_386_GOTPC),
 196                 REL_TYPE(R_386_8),
 197                 REL_TYPE(R_386_PC8),
 198                 REL_TYPE(R_386_16),
 199                 REL_TYPE(R_386_PC16),
 200 #undef REL_TYPE
 201         };
 202         const char *name = "unknown type rel type name";
 203         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 204                 name = type_name[type];
 205         }
 206         return name;
 207 }
 208
 209 static const char *sec_name(unsigned shndx)
 210 {
 211         const char *sec_strtab;
 212         const char *name;
 213         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 214         name = "<noname>";
 215         if (shndx < ehdr.e_shnum) {
 216                 name = sec_strtab + secs[shndx].shdr.sh_name;
 217         }
 218         else if (shndx == SHN_ABS) {
 219                 name = "ABSOLUTE";
 220         }
 221         else if (shndx == SHN_COMMON) {
 222                 name = "COMMON";
 223         }
 224         return name;
 225 }
 226
 227 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 228 {
 229         const char *name;
 230         name = "<noname>";
 231         if (sym->st_name) {
 232                 name = sym_strtab + sym->st_name;
 233         }
 234         else {
 235                 name = sec_name(sym->st_shndx);
 236         }
 237         return name;
 238 }
 239
 240
 241
 242 #if BYTE_ORDER == LITTLE_ENDIAN
 243 #define le16_to_cpu(val) (val)
 244 #define le32_to_cpu(val) (val)
 245 #endif
 246 #if BYTE_ORDER == BIG_ENDIAN
 247 #define le16_to_cpu(val) bswap_16(val)
 248 #define le32_to_cpu(val) bswap_32(val)
 249 #endif
 250
 251 static uint16_t elf16_to_cpu(uint16_t val)
 252 {
 253         return le16_to_cpu(val);
 254 }
 255
 256 static uint32_t elf32_to_cpu(uint32_t val)
 257 {
 258         return le32_to_cpu(val);
 259 }
 260
 261 static void read_ehdr(FILE *fp)
 262 {
 263         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 264                 die("Cannot read ELF header: %s\n",
 265                         strerror(errno));
 266         }
 267         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 268                 die("No ELF magic\n");
 269         }
 270         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 271                 die("Not a 32 bit executable\n");
 272         }
 273         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 274                 die("Not a LSB ELF executable\n");
 275         }
 276         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 277                 die("Unknown ELF version\n");
 278         }
 279         /* Convert the fields to native endian */
 280         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 281         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 282         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 283         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 284         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 285         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 286         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 287         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 288         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 289         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 290         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 291         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 292         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 293
 294         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 295                 die("Unsupported ELF header type\n");
 296         }
 297         if (ehdr.e_machine != EM_386) {
 298                 die("Not for x86\n");
 299         }
 300         if (ehdr.e_version != EV_CURRENT) {
 301                 die("Unknown ELF version\n");
 302         }
 303         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 304                 die("Bad Elf header size\n");
 305         }
 306         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 307                 die("Bad program header entry\n");
 308         }
 309         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 310                 die("Bad section header entry\n");
 311         }
 312         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 313                 die("String table index out of bounds\n");
 314         }
 315 }
 316
 317 static void read_shdrs(FILE *fp)
 318 {
 319         int i;
 320         Elf32_Shdr shdr;
 321
 322         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 323         if (!secs) {
 324                 die("Unable to allocate %d section headers\n",
 325                     ehdr.e_shnum);
 326         }
 327         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 328                 die("Seek to %d failed: %s\n",
 329                         ehdr.e_shoff, strerror(errno));
 330         }
 331         for (i = 0; i < ehdr.e_shnum; i++) {
 332                 struct section *sec = &secs[i];
 333                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 334                         die("Cannot read ELF section headers %d/%d: %s\n",
 335                             i, ehdr.e_shnum, strerror(errno));
 336                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 337                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 338                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 339                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 340                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 341                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 342                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 343                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 344                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 345                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 346                 if (sec->shdr.sh_link < ehdr.e_shnum)
 347                         sec->link = &secs[sec->shdr.sh_link];
 348         }
 349
 350 }
 351
 352 static void read_strtabs(FILE *fp)
 353 {
 354         int i;
 355         for (i = 0; i < ehdr.e_shnum; i++) {
 356                 struct section *sec = &secs[i];
 357                 if (sec->shdr.sh_type != SHT_STRTAB) {
 358                         continue;
 359                 }
 360                 sec->strtab = malloc(sec->shdr.sh_size);
 361                 if (!sec->strtab) {
 362                         die("malloc of %d bytes for strtab failed\n",
 363                                 sec->shdr.sh_size);
 364                 }
 365                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 366                         die("Seek to %d failed: %s\n",
 367                                 sec->shdr.sh_offset, strerror(errno));
 368                 }
 369                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 370                     != sec->shdr.sh_size) {
 371                         die("Cannot read symbol table: %s\n",
 372                                 strerror(errno));
 373                 }
 374         }
 375 }
 376
 377 static void read_symtabs(FILE *fp)
 378 {
 379         int i,j;
 380         for (i = 0; i < ehdr.e_shnum; i++) {
 381                 struct section *sec = &secs[i];
 382                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 383                         continue;
 384                 }
 385                 sec->symtab = malloc(sec->shdr.sh_size);
 386                 if (!sec->symtab) {
 387                         die("malloc of %d bytes for symtab failed\n",
 388                                 sec->shdr.sh_size);
 389                 }
 390                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 391                         die("Seek to %d failed: %s\n",
 392                                 sec->shdr.sh_offset, strerror(errno));
 393                 }
 394                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 395                     != sec->shdr.sh_size) {
 396                         die("Cannot read symbol table: %s\n",
 397                                 strerror(errno));
 398                 }
 399                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 400                         Elf32_Sym *sym = &sec->symtab[j];
 401                         sym->st_name  = elf32_to_cpu(sym->st_name);
 402                         sym->st_value = elf32_to_cpu(sym->st_value);
 403                         sym->st_size  = elf32_to_cpu(sym->st_size);
 404                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 405                 }
 406         }
 407 }
 408
 409
 410 static void read_relocs(FILE *fp)
 411 {
 412         int i,j;
 413         for (i = 0; i < ehdr.e_shnum; i++) {
 414                 struct section *sec = &secs[i];
 415                 if (sec->shdr.sh_type != SHT_REL) {
 416                         continue;
 417                 }
 418                 sec->reltab = malloc(sec->shdr.sh_size);
 419                 if (!sec->reltab) {
 420                         die("malloc of %d bytes for relocs failed\n",
 421                                 sec->shdr.sh_size);
 422                 }
 423                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 424                         die("Seek to %d failed: %s\n",
 425                                 sec->shdr.sh_offset, strerror(errno));
 426                 }
 427                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 428                     != sec->shdr.sh_size) {
 429                         die("Cannot read symbol table: %s\n",
 430                                 strerror(errno));
 431                 }
 432                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 433                         Elf32_Rel *rel = &sec->reltab[j];
 434                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 435                         rel->r_info   = elf32_to_cpu(rel->r_info);
 436                 }
 437         }
 438 }
 439
 440
 441 static void print_absolute_symbols(void)
 442 {
 443         int i;
 444         printf("Absolute symbols\n");
 445         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 446         for (i = 0; i < ehdr.e_shnum; i++) {
 447                 struct section *sec = &secs[i];
 448                 char *sym_strtab;
 449                 int j;
 450
 451                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 452                         continue;
 453                 }
 454                 sym_strtab = sec->link->strtab;
 455                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 456                         Elf32_Sym *sym;
 457                         const char *name;
 458                         sym = &sec->symtab[j];
 459                         name = sym_name(sym_strtab, sym);
 460                         if (sym->st_shndx != SHN_ABS) {
 461                                 continue;
 462                         }
 463                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 464                                 j, sym->st_value, sym->st_size,
 465                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 466                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 467                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 468                                 name);
 469                 }
 470         }
 471         printf("\n");
 472 }
 473
 474 static void print_absolute_relocs(void)
 475 {
 476         int i, printed = 0;
 477
 478         for (i = 0; i < ehdr.e_shnum; i++) {
 479                 struct section *sec = &secs[i];
 480                 struct section *sec_applies, *sec_symtab;
 481                 char *sym_strtab;
 482                 Elf32_Sym *sh_symtab;
 483                 int j;
 484                 if (sec->shdr.sh_type != SHT_REL) {
 485                         continue;
 486                 }
 487                 sec_symtab  = sec->link;
 488                 sec_applies = &secs[sec->shdr.sh_info];
 489                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 490                         continue;
 491                 }
 492                 sh_symtab  = sec_symtab->symtab;
 493                 sym_strtab = sec_symtab->link->strtab;
 494                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 495                         Elf32_Rel *rel;
 496                         Elf32_Sym *sym;
 497                         const char *name;
 498                         rel = &sec->reltab[j];
 499                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 500                         name = sym_name(sym_strtab, sym);
 501                         if (sym->st_shndx != SHN_ABS) {
 502                                 continue;
 503                         }
 504
 505                         /* Absolute symbols are not relocated if bzImage is
 506                          * loaded at a non-compiled address. Display a warning
 507                          * to user at compile time about the absolute
 508                          * relocations present.
 509                          *
 510                          * User need to audit the code to make sure
 511                          * some symbols which should have been section
 512                          * relative have not become absolute because of some
 513                          * linker optimization or wrong programming usage.
 514                          *
 515                          * Before warning check if this absolute symbol
 516                          * relocation is harmless.
 517                          */
 518                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 519                                 continue;
 520
 521                         if (!printed) {
 522                                 printf("WARNING: Absolute relocations"
 523                                         " present\n");
 524                                 printf("Offset     Info     Type     Sym.Value "
 525                                         "Sym.Name\n");
 526                                 printed = 1;
 527                         }
 528
 529                         printf("%08x %08x %10s %08x  %s\n",
 530                                 rel->r_offset,
 531                                 rel->r_info,
 532                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 533                                 sym->st_value,
 534                                 name);
 535                 }
 536         }
 537
 538         if (printed)
 539                 printf("\n");
 540 }
 541
 542 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 543                         int use_real_mode)
 544 {
 545         int i;
 546         /* Walk through the relocations */
 547         for (i = 0; i < ehdr.e_shnum; i++) {
 548                 char *sym_strtab;
 549                 Elf32_Sym *sh_symtab;
 550                 struct section *sec_applies, *sec_symtab;
 551                 int j;
 552                 struct section *sec = &secs[i];
 553
 554                 if (sec->shdr.sh_type != SHT_REL) {
 555                         continue;
 556                 }
 557                 sec_symtab  = sec->link;
 558                 sec_applies = &secs[sec->shdr.sh_info];
 559                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 560                         continue;
 561                 }
 562                 sh_symtab = sec_symtab->symtab;
 563                 sym_strtab = sec_symtab->link->strtab;
 564                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 565                         Elf32_Rel *rel;
 566                         Elf32_Sym *sym;
 567                         unsigned r_type;
 568                         const char *symname;
 569                         rel = &sec->reltab[j];
 570                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 571                         r_type = ELF32_R_TYPE(rel->r_info);
 572
 573                         switch (r_type) {
 574                         case R_386_NONE:
 575                         case R_386_PC32:
 576                         case R_386_PC16:
 577                         case R_386_PC8:
 578                                 /*
 579                                  * NONE can be ignored and and PC relative
 580                                  * relocations don't need to be adjusted.
 581                                  */
 582                                 break;
 583
 584                         case R_386_16:
 585                                 symname = sym_name(sym_strtab, sym);
 586                                 if (!use_real_mode)
 587                                         goto bad;
 588                                 if (sym->st_shndx == SHN_ABS) {
 589                                         if (is_reloc(S_ABS, symname))
 590                                                 break;
 591                                         else if (!is_reloc(S_SEG, symname))
 592                                                 goto bad;
 593                                 } else {
 594                                         if (is_reloc(S_LIN, symname))
 595                                                 goto bad;
 596                                         else
 597                                                 break;
 598                                 }
 599                                 visit(rel, sym);
 600                                 break;
 601
 602                         case R_386_32:
 603                                 symname = sym_name(sym_strtab, sym);
 604                                 if (sym->st_shndx == SHN_ABS) {
 605                                         if (is_reloc(S_ABS, symname))
 606                                                 break;
 607                                         else if (!is_reloc(S_REL, symname))
 608                                                 goto bad;
 609                                 } else {
 610                                         if (use_real_mode &&
 611                                             !is_reloc(S_LIN, symname))
 612                                                 break;
 613                                 }
 614                                 visit(rel, sym);
 615                                 break;
 616                         default:
 617                                 die("Unsupported relocation type: %s (%d)\n",
 618                                     rel_type(r_type), r_type);
 619                                 break;
 620                         bad:
 621                                 symname = sym_name(sym_strtab, sym);
 622                                 die("Invalid %s relocation: %s\n",
 623                                     rel_type(r_type), symname);
 624                         }
 625                 }
 626         }
 627 }
 628
 629 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 630 {
 631         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 632                 reloc16_count++;
 633         else
 634                 reloc_count++;
 635 }
 636
 637 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 638 {
 639         /* Remember the address that needs to be adjusted. */
 640         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 641                 relocs16[reloc16_idx++] = rel->r_offset;
 642         else
 643                 relocs[reloc_idx++] = rel->r_offset;
 644 }
 645
 646 static int cmp_relocs(const void *va, const void *vb)
 647 {
 648         const unsigned long *a, *b;
 649         a = va; b = vb;
 650         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 651 }
 652
 653 static int write32(unsigned int v, FILE *f)
 654 {
 655         unsigned char buf[4];
 656
 657         put_unaligned_le32(v, buf);
 658         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 659 }
 660
 661 static void emit_relocs(int as_text, int use_real_mode)
 662 {
 663         int i;
 664         /* Count how many relocations I have and allocate space for them. */
 665         reloc_count = 0;
 666         walk_relocs(count_reloc, use_real_mode);
 667         relocs = malloc(reloc_count * sizeof(relocs[0]));
 668         if (!relocs) {
 669                 die("malloc of %d entries for relocs failed\n",
 670                         reloc_count);
 671         }
 672
 673         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 674         if (!relocs16) {
 675                 die("malloc of %d entries for relocs16 failed\n",
 676                         reloc16_count);
 677         }
 678         /* Collect up the relocations */
 679         reloc_idx = 0;
 680         walk_relocs(collect_reloc, use_real_mode);
 681
 682         if (reloc16_count && !use_real_mode)
 683                 die("Segment relocations found but --realmode not specified\n");
 684
 685         /* Order the relocations for more efficient processing */
 686         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 687         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 688
 689         /* Print the relocations */
 690         if (as_text) {
 691                 /* Print the relocations in a form suitable that
 692                  * gas will like.
 693                  */
 694                 printf(".section \".data.reloc\",\"a\"\n");
 695                 printf(".balign 4\n");
 696                 if (use_real_mode) {
 697                         printf("\t.long %lu\n", reloc16_count);
 698                         for (i = 0; i < reloc16_count; i++)
 699                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 700                         printf("\t.long %lu\n", reloc_count);
 701                         for (i = 0; i < reloc_count; i++) {
 702                                 printf("\t.long 0x%08lx\n", relocs[i]);
 703                         }
 704                 } else {
 705                         /* Print a stop */
 706                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 707                         for (i = 0; i < reloc_count; i++) {
 708                                 printf("\t.long 0x%08lx\n", relocs[i]);
 709                         }
 710                 }
 711
 712                 printf("\n");
 713         }
 714         else {
 715                 if (use_real_mode) {
 716                         write32(reloc16_count, stdout);
 717                         for (i = 0; i < reloc16_count; i++)
 718                                 write32(relocs16[i], stdout);
 719                         write32(reloc_count, stdout);
 720
 721                         /* Now print each relocation */
 722                         for (i = 0; i < reloc_count; i++)
 723                                 write32(relocs[i], stdout);
 724                 } else {
 725                         /* Print a stop */
 726                         write32(0, stdout);
 727
 728                         /* Now print each relocation */
 729                         for (i = 0; i < reloc_count; i++) {
 730                                 write32(relocs[i], stdout);
 731                         }
 732                 }
 733         }
 734 }
 735
 736 static void usage(void)
 737 {
 738         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 739 }
 740
 741 int main(int argc, char **argv)
 742 {
 743         int show_absolute_syms, show_absolute_relocs;
 744         int as_text, use_real_mode;
 745         const char *fname;
 746         FILE *fp;
 747         int i;
 748
 749         show_absolute_syms = 0;
 750         show_absolute_relocs = 0;
 751         as_text = 0;
 752         use_real_mode = 0;
 753         fname = NULL;
 754         for (i = 1; i < argc; i++) {
 755                 char *arg = argv[i];
 756                 if (*arg == '-') {
 757                         if (strcmp(arg, "--abs-syms") == 0) {
 758                                 show_absolute_syms = 1;
 759                                 continue;
 760                         }
 761                         if (strcmp(arg, "--abs-relocs") == 0) {
 762                                 show_absolute_relocs = 1;
 763                                 continue;
 764                         }
 765                         if (strcmp(arg, "--text") == 0) {
 766                                 as_text = 1;
 767                                 continue;
 768                         }
 769                         if (strcmp(arg, "--realmode") == 0) {
 770                                 use_real_mode = 1;
 771                                 continue;
 772                         }
 773                 }
 774                 else if (!fname) {
 775                         fname = arg;
 776                         continue;
 777                 }
 778                 usage();
 779         }
 780         if (!fname) {
 781                 usage();
 782         }
 783         regex_init(use_real_mode);
 784         fp = fopen(fname, "r");
 785         if (!fp) {
 786                 die("Cannot open %s: %s\n",
 787                         fname, strerror(errno));
 788         }
 789         read_ehdr(fp);
 790         read_shdrs(fp);
 791         read_strtabs(fp);
 792         read_symtabs(fp);
 793         read_relocs(fp);
 794         if (show_absolute_syms) {
 795                 print_absolute_symbols();
 796                 return 0;
 797         }
 798         if (show_absolute_relocs) {
 799                 print_absolute_relocs();
 800                 return 0;
 801         }
 802         emit_relocs(as_text, use_real_mode);
 803         return 0;
 804 }