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 #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         "^(__init_(begin|end)|"
  60         "__x86_cpu_dev_(start|end)|"
  61         "(__parainstructions|__alt_instructions)(|_end)|"
  62         "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
  63         "_end)$"
  64 };
  65
  66
  67 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  68 /*
  69  * These are 16-bit segment symbols when compiling 16-bit code.
  70  */
  71         [S_SEG] =
  72         "^real_mode_seg$",
  73
  74 /*
  75  * These are offsets belonging to segments, as opposed to linear addresses,
  76  * when compiling 16-bit code.
  77  */
  78         [S_LIN] =
  79         "^pa_",
  80 };
  81
  82 static const char * const *sym_regex;
  83
  84 static regex_t sym_regex_c[S_NSYMTYPES];
  85 static int is_reloc(enum symtype type, const char *sym_name)
  86 {
  87         return sym_regex[type] &&
  88                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
  89 }
  90
  91 static void regex_init(int use_real_mode)
  92 {
  93         char errbuf[128];
  94         int err;
  95         int i;
  96
  97         if (use_real_mode)
  98                 sym_regex = sym_regex_realmode;
  99         else
 100                 sym_regex = sym_regex_kernel;
 101
 102         for (i = 0; i < S_NSYMTYPES; i++) {
 103                 if (!sym_regex[i])
 104                         continue;
 105
 106                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 107                               REG_EXTENDED|REG_NOSUB);
 108
 109                 if (err) {
 110                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 111                         die("%s", errbuf);
 112                 }
 113         }
 114 }
 115
 116 static void die(char *fmt, ...)
 117 {
 118         va_list ap;
 119         va_start(ap, fmt);
 120         vfprintf(stderr, fmt, ap);
 121         va_end(ap);
 122         exit(1);
 123 }
 124
 125 static const char *sym_type(unsigned type)
 126 {
 127         static const char *type_name[] = {
 128 #define SYM_TYPE(X) [X] = #X
 129                 SYM_TYPE(STT_NOTYPE),
 130                 SYM_TYPE(STT_OBJECT),
 131                 SYM_TYPE(STT_FUNC),
 132                 SYM_TYPE(STT_SECTION),
 133                 SYM_TYPE(STT_FILE),
 134                 SYM_TYPE(STT_COMMON),
 135                 SYM_TYPE(STT_TLS),
 136 #undef SYM_TYPE
 137         };
 138         const char *name = "unknown sym type name";
 139         if (type < ARRAY_SIZE(type_name)) {
 140                 name = type_name[type];
 141         }
 142         return name;
 143 }
 144
 145 static const char *sym_bind(unsigned bind)
 146 {
 147         static const char *bind_name[] = {
 148 #define SYM_BIND(X) [X] = #X
 149                 SYM_BIND(STB_LOCAL),
 150                 SYM_BIND(STB_GLOBAL),
 151                 SYM_BIND(STB_WEAK),
 152 #undef SYM_BIND
 153         };
 154         const char *name = "unknown sym bind name";
 155         if (bind < ARRAY_SIZE(bind_name)) {
 156                 name = bind_name[bind];
 157         }
 158         return name;
 159 }
 160
 161 static const char *sym_visibility(unsigned visibility)
 162 {
 163         static const char *visibility_name[] = {
 164 #define SYM_VISIBILITY(X) [X] = #X
 165                 SYM_VISIBILITY(STV_DEFAULT),
 166                 SYM_VISIBILITY(STV_INTERNAL),
 167                 SYM_VISIBILITY(STV_HIDDEN),
 168                 SYM_VISIBILITY(STV_PROTECTED),
 169 #undef SYM_VISIBILITY
 170         };
 171         const char *name = "unknown sym visibility name";
 172         if (visibility < ARRAY_SIZE(visibility_name)) {
 173                 name = visibility_name[visibility];
 174         }
 175         return name;
 176 }
 177
 178 static const char *rel_type(unsigned type)
 179 {
 180         static const char *type_name[] = {
 181 #define REL_TYPE(X) [X] = #X
 182                 REL_TYPE(R_386_NONE),
 183                 REL_TYPE(R_386_32),
 184                 REL_TYPE(R_386_PC32),
 185                 REL_TYPE(R_386_GOT32),
 186                 REL_TYPE(R_386_PLT32),
 187                 REL_TYPE(R_386_COPY),
 188                 REL_TYPE(R_386_GLOB_DAT),
 189                 REL_TYPE(R_386_JMP_SLOT),
 190                 REL_TYPE(R_386_RELATIVE),
 191                 REL_TYPE(R_386_GOTOFF),
 192                 REL_TYPE(R_386_GOTPC),
 193                 REL_TYPE(R_386_8),
 194                 REL_TYPE(R_386_PC8),
 195                 REL_TYPE(R_386_16),
 196                 REL_TYPE(R_386_PC16),
 197 #undef REL_TYPE
 198         };
 199         const char *name = "unknown type rel type name";
 200         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 201                 name = type_name[type];
 202         }
 203         return name;
 204 }
 205
 206 static const char *sec_name(unsigned shndx)
 207 {
 208         const char *sec_strtab;
 209         const char *name;
 210         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 211         name = "<noname>";
 212         if (shndx < ehdr.e_shnum) {
 213                 name = sec_strtab + secs[shndx].shdr.sh_name;
 214         }
 215         else if (shndx == SHN_ABS) {
 216                 name = "ABSOLUTE";
 217         }
 218         else if (shndx == SHN_COMMON) {
 219                 name = "COMMON";
 220         }
 221         return name;
 222 }
 223
 224 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 225 {
 226         const char *name;
 227         name = "<noname>";
 228         if (sym->st_name) {
 229                 name = sym_strtab + sym->st_name;
 230         }
 231         else {
 232                 name = sec_name(sym->st_shndx);
 233         }
 234         return name;
 235 }
 236
 237
 238
 239 #if BYTE_ORDER == LITTLE_ENDIAN
 240 #define le16_to_cpu(val) (val)
 241 #define le32_to_cpu(val) (val)
 242 #endif
 243 #if BYTE_ORDER == BIG_ENDIAN
 244 #define le16_to_cpu(val) bswap_16(val)
 245 #define le32_to_cpu(val) bswap_32(val)
 246 #endif
 247
 248 static uint16_t elf16_to_cpu(uint16_t val)
 249 {
 250         return le16_to_cpu(val);
 251 }
 252
 253 static uint32_t elf32_to_cpu(uint32_t val)
 254 {
 255         return le32_to_cpu(val);
 256 }
 257
 258 static void read_ehdr(FILE *fp)
 259 {
 260         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 261                 die("Cannot read ELF header: %s\n",
 262                         strerror(errno));
 263         }
 264         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 265                 die("No ELF magic\n");
 266         }
 267         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 268                 die("Not a 32 bit executable\n");
 269         }
 270         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 271                 die("Not a LSB ELF executable\n");
 272         }
 273         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 274                 die("Unknown ELF version\n");
 275         }
 276         /* Convert the fields to native endian */
 277         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 278         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 279         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 280         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 281         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 282         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 283         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 284         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 285         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 286         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 287         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 288         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 289         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 290
 291         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 292                 die("Unsupported ELF header type\n");
 293         }
 294         if (ehdr.e_machine != EM_386) {
 295                 die("Not for x86\n");
 296         }
 297         if (ehdr.e_version != EV_CURRENT) {
 298                 die("Unknown ELF version\n");
 299         }
 300         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 301                 die("Bad Elf header size\n");
 302         }
 303         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 304                 die("Bad program header entry\n");
 305         }
 306         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 307                 die("Bad section header entry\n");
 308         }
 309         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 310                 die("String table index out of bounds\n");
 311         }
 312 }
 313
 314 static void read_shdrs(FILE *fp)
 315 {
 316         int i;
 317         Elf32_Shdr shdr;
 318
 319         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 320         if (!secs) {
 321                 die("Unable to allocate %d section headers\n",
 322                     ehdr.e_shnum);
 323         }
 324         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 325                 die("Seek to %d failed: %s\n",
 326                         ehdr.e_shoff, strerror(errno));
 327         }
 328         for (i = 0; i < ehdr.e_shnum; i++) {
 329                 struct section *sec = &secs[i];
 330                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 331                         die("Cannot read ELF section headers %d/%d: %s\n",
 332                             i, ehdr.e_shnum, strerror(errno));
 333                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 334                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 335                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 336                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 337                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 338                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 339                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 340                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 341                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 342                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 343                 if (sec->shdr.sh_link < ehdr.e_shnum)
 344                         sec->link = &secs[sec->shdr.sh_link];
 345         }
 346
 347 }
 348
 349 static void read_strtabs(FILE *fp)
 350 {
 351         int i;
 352         for (i = 0; i < ehdr.e_shnum; i++) {
 353                 struct section *sec = &secs[i];
 354                 if (sec->shdr.sh_type != SHT_STRTAB) {
 355                         continue;
 356                 }
 357                 sec->strtab = malloc(sec->shdr.sh_size);
 358                 if (!sec->strtab) {
 359                         die("malloc of %d bytes for strtab failed\n",
 360                                 sec->shdr.sh_size);
 361                 }
 362                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 363                         die("Seek to %d failed: %s\n",
 364                                 sec->shdr.sh_offset, strerror(errno));
 365                 }
 366                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 367                     != sec->shdr.sh_size) {
 368                         die("Cannot read symbol table: %s\n",
 369                                 strerror(errno));
 370                 }
 371         }
 372 }
 373
 374 static void read_symtabs(FILE *fp)
 375 {
 376         int i,j;
 377         for (i = 0; i < ehdr.e_shnum; i++) {
 378                 struct section *sec = &secs[i];
 379                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 380                         continue;
 381                 }
 382                 sec->symtab = malloc(sec->shdr.sh_size);
 383                 if (!sec->symtab) {
 384                         die("malloc of %d bytes for symtab failed\n",
 385                                 sec->shdr.sh_size);
 386                 }
 387                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 388                         die("Seek to %d failed: %s\n",
 389                                 sec->shdr.sh_offset, strerror(errno));
 390                 }
 391                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 392                     != sec->shdr.sh_size) {
 393                         die("Cannot read symbol table: %s\n",
 394                                 strerror(errno));
 395                 }
 396                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 397                         Elf32_Sym *sym = &sec->symtab[j];
 398                         sym->st_name  = elf32_to_cpu(sym->st_name);
 399                         sym->st_value = elf32_to_cpu(sym->st_value);
 400                         sym->st_size  = elf32_to_cpu(sym->st_size);
 401                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 402                 }
 403         }
 404 }
 405
 406
 407 static void read_relocs(FILE *fp)
 408 {
 409         int i,j;
 410         for (i = 0; i < ehdr.e_shnum; i++) {
 411                 struct section *sec = &secs[i];
 412                 if (sec->shdr.sh_type != SHT_REL) {
 413                         continue;
 414                 }
 415                 sec->reltab = malloc(sec->shdr.sh_size);
 416                 if (!sec->reltab) {
 417                         die("malloc of %d bytes for relocs failed\n",
 418                                 sec->shdr.sh_size);
 419                 }
 420                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 421                         die("Seek to %d failed: %s\n",
 422                                 sec->shdr.sh_offset, strerror(errno));
 423                 }
 424                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 425                     != sec->shdr.sh_size) {
 426                         die("Cannot read symbol table: %s\n",
 427                                 strerror(errno));
 428                 }
 429                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 430                         Elf32_Rel *rel = &sec->reltab[j];
 431                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 432                         rel->r_info   = elf32_to_cpu(rel->r_info);
 433                 }
 434         }
 435 }
 436
 437
 438 static void print_absolute_symbols(void)
 439 {
 440         int i;
 441         printf("Absolute symbols\n");
 442         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 443         for (i = 0; i < ehdr.e_shnum; i++) {
 444                 struct section *sec = &secs[i];
 445                 char *sym_strtab;
 446                 int j;
 447
 448                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 449                         continue;
 450                 }
 451                 sym_strtab = sec->link->strtab;
 452                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 453                         Elf32_Sym *sym;
 454                         const char *name;
 455                         sym = &sec->symtab[j];
 456                         name = sym_name(sym_strtab, sym);
 457                         if (sym->st_shndx != SHN_ABS) {
 458                                 continue;
 459                         }
 460                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 461                                 j, sym->st_value, sym->st_size,
 462                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 463                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 464                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 465                                 name);
 466                 }
 467         }
 468         printf("\n");
 469 }
 470
 471 static void print_absolute_relocs(void)
 472 {
 473         int i, printed = 0;
 474
 475         for (i = 0; i < ehdr.e_shnum; i++) {
 476                 struct section *sec = &secs[i];
 477                 struct section *sec_applies, *sec_symtab;
 478                 char *sym_strtab;
 479                 Elf32_Sym *sh_symtab;
 480                 int j;
 481                 if (sec->shdr.sh_type != SHT_REL) {
 482                         continue;
 483                 }
 484                 sec_symtab  = sec->link;
 485                 sec_applies = &secs[sec->shdr.sh_info];
 486                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 487                         continue;
 488                 }
 489                 sh_symtab  = sec_symtab->symtab;
 490                 sym_strtab = sec_symtab->link->strtab;
 491                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 492                         Elf32_Rel *rel;
 493                         Elf32_Sym *sym;
 494                         const char *name;
 495                         rel = &sec->reltab[j];
 496                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 497                         name = sym_name(sym_strtab, sym);
 498                         if (sym->st_shndx != SHN_ABS) {
 499                                 continue;
 500                         }
 501
 502                         /* Absolute symbols are not relocated if bzImage is
 503                          * loaded at a non-compiled address. Display a warning
 504                          * to user at compile time about the absolute
 505                          * relocations present.
 506                          *
 507                          * User need to audit the code to make sure
 508                          * some symbols which should have been section
 509                          * relative have not become absolute because of some
 510                          * linker optimization or wrong programming usage.
 511                          *
 512                          * Before warning check if this absolute symbol
 513                          * relocation is harmless.
 514                          */
 515                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 516                                 continue;
 517
 518                         if (!printed) {
 519                                 printf("WARNING: Absolute relocations"
 520                                         " present\n");
 521                                 printf("Offset     Info     Type     Sym.Value "
 522                                         "Sym.Name\n");
 523                                 printed = 1;
 524                         }
 525
 526                         printf("%08x %08x %10s %08x  %s\n",
 527                                 rel->r_offset,
 528                                 rel->r_info,
 529                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 530                                 sym->st_value,
 531                                 name);
 532                 }
 533         }
 534
 535         if (printed)
 536                 printf("\n");
 537 }
 538
 539 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 540                         int use_real_mode)
 541 {
 542         int i;
 543         /* Walk through the relocations */
 544         for (i = 0; i < ehdr.e_shnum; i++) {
 545                 char *sym_strtab;
 546                 Elf32_Sym *sh_symtab;
 547                 struct section *sec_applies, *sec_symtab;
 548                 int j;
 549                 struct section *sec = &secs[i];
 550
 551                 if (sec->shdr.sh_type != SHT_REL) {
 552                         continue;
 553                 }
 554                 sec_symtab  = sec->link;
 555                 sec_applies = &secs[sec->shdr.sh_info];
 556                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 557                         continue;
 558                 }
 559                 sh_symtab = sec_symtab->symtab;
 560                 sym_strtab = sec_symtab->link->strtab;
 561                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 562                         Elf32_Rel *rel;
 563                         Elf32_Sym *sym;
 564                         unsigned r_type;
 565                         const char *symname;
 566                         rel = &sec->reltab[j];
 567                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 568                         r_type = ELF32_R_TYPE(rel->r_info);
 569
 570                         switch (r_type) {
 571                         case R_386_NONE:
 572                         case R_386_PC32:
 573                         case R_386_PC16:
 574                         case R_386_PC8:
 575                                 /*
 576                                  * NONE can be ignored and and PC relative
 577                                  * relocations don't need to be adjusted.
 578                                  */
 579                                 break;
 580
 581                         case R_386_16:
 582                                 symname = sym_name(sym_strtab, sym);
 583                                 if (!use_real_mode)
 584                                         goto bad;
 585                                 if (sym->st_shndx == SHN_ABS) {
 586                                         if (is_reloc(S_ABS, symname))
 587                                                 break;
 588                                         else if (!is_reloc(S_SEG, symname))
 589                                                 goto bad;
 590                                 } else {
 591                                         if (is_reloc(S_LIN, symname))
 592                                                 goto bad;
 593                                         else
 594                                                 break;
 595                                 }
 596                                 visit(rel, sym);
 597                                 break;
 598
 599                         case R_386_32:
 600                                 symname = sym_name(sym_strtab, sym);
 601                                 if (sym->st_shndx == SHN_ABS) {
 602                                         if (is_reloc(S_ABS, symname))
 603                                                 break;
 604                                         else if (!is_reloc(S_REL, symname))
 605                                                 goto bad;
 606                                 } else {
 607                                         if (use_real_mode &&
 608                                             !is_reloc(S_LIN, symname))
 609                                                 break;
 610                                 }
 611                                 visit(rel, sym);
 612                                 break;
 613                         default:
 614                                 die("Unsupported relocation type: %s (%d)\n",
 615                                     rel_type(r_type), r_type);
 616                                 break;
 617                         bad:
 618                                 symname = sym_name(sym_strtab, sym);
 619                                 die("Invalid %s relocation: %s\n",
 620                                     rel_type(r_type), symname);
 621                         }
 622                 }
 623         }
 624 }
 625
 626 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 627 {
 628         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 629                 reloc16_count++;
 630         else
 631                 reloc_count++;
 632 }
 633
 634 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 635 {
 636         /* Remember the address that needs to be adjusted. */
 637         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 638                 relocs16[reloc16_idx++] = rel->r_offset;
 639         else
 640                 relocs[reloc_idx++] = rel->r_offset;
 641 }
 642
 643 static int cmp_relocs(const void *va, const void *vb)
 644 {
 645         const unsigned long *a, *b;
 646         a = va; b = vb;
 647         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 648 }
 649
 650 static int write32(unsigned int v, FILE *f)
 651 {
 652         unsigned char buf[4];
 653
 654         put_unaligned_le32(v, buf);
 655         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 656 }
 657
 658 static void emit_relocs(int as_text, int use_real_mode)
 659 {
 660         int i;
 661         /* Count how many relocations I have and allocate space for them. */
 662         reloc_count = 0;
 663         walk_relocs(count_reloc, use_real_mode);
 664         relocs = malloc(reloc_count * sizeof(relocs[0]));
 665         if (!relocs) {
 666                 die("malloc of %d entries for relocs failed\n",
 667                         reloc_count);
 668         }
 669
 670         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 671         if (!relocs16) {
 672                 die("malloc of %d entries for relocs16 failed\n",
 673                         reloc16_count);
 674         }
 675         /* Collect up the relocations */
 676         reloc_idx = 0;
 677         walk_relocs(collect_reloc, use_real_mode);
 678
 679         if (reloc16_count && !use_real_mode)
 680                 die("Segment relocations found but --realmode not specified\n");
 681
 682         /* Order the relocations for more efficient processing */
 683         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 684         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 685
 686         /* Print the relocations */
 687         if (as_text) {
 688                 /* Print the relocations in a form suitable that
 689                  * gas will like.
 690                  */
 691                 printf(".section \".data.reloc\",\"a\"\n");
 692                 printf(".balign 4\n");
 693                 if (use_real_mode) {
 694                         printf("\t.long %lu\n", reloc16_count);
 695                         for (i = 0; i < reloc16_count; i++)
 696                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 697                         printf("\t.long %lu\n", reloc_count);
 698                         for (i = 0; i < reloc_count; i++) {
 699                                 printf("\t.long 0x%08lx\n", relocs[i]);
 700                         }
 701                 } else {
 702                         /* Print a stop */
 703                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 704                         for (i = 0; i < reloc_count; i++) {
 705                                 printf("\t.long 0x%08lx\n", relocs[i]);
 706                         }
 707                 }
 708
 709                 printf("\n");
 710         }
 711         else {
 712                 if (use_real_mode) {
 713                         write32(reloc16_count, stdout);
 714                         for (i = 0; i < reloc16_count; i++)
 715                                 write32(relocs16[i], stdout);
 716                         write32(reloc_count, stdout);
 717
 718                         /* Now print each relocation */
 719                         for (i = 0; i < reloc_count; i++)
 720                                 write32(relocs[i], stdout);
 721                 } else {
 722                         /* Print a stop */
 723                         write32(0, stdout);
 724
 725                         /* Now print each relocation */
 726                         for (i = 0; i < reloc_count; i++) {
 727                                 write32(relocs[i], stdout);
 728                         }
 729                 }
 730         }
 731 }
 732
 733 static void usage(void)
 734 {
 735         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 736 }
 737
 738 int main(int argc, char **argv)
 739 {
 740         int show_absolute_syms, show_absolute_relocs;
 741         int as_text, use_real_mode;
 742         const char *fname;
 743         FILE *fp;
 744         int i;
 745
 746         show_absolute_syms = 0;
 747         show_absolute_relocs = 0;
 748         as_text = 0;
 749         use_real_mode = 0;
 750         fname = NULL;
 751         for (i = 1; i < argc; i++) {
 752                 char *arg = argv[i];
 753                 if (*arg == '-') {
 754                         if (strcmp(arg, "--abs-syms") == 0) {
 755                                 show_absolute_syms = 1;
 756                                 continue;
 757                         }
 758                         if (strcmp(arg, "--abs-relocs") == 0) {
 759                                 show_absolute_relocs = 1;
 760                                 continue;
 761                         }
 762                         if (strcmp(arg, "--text") == 0) {
 763                                 as_text = 1;
 764                                 continue;
 765                         }
 766                         if (strcmp(arg, "--realmode") == 0) {
 767                                 use_real_mode = 1;
 768                                 continue;
 769                         }
 770                 }
 771                 else if (!fname) {
 772                         fname = arg;
 773                         continue;
 774                 }
 775                 usage();
 776         }
 777         if (!fname) {
 778                 usage();
 779         }
 780         regex_init(use_real_mode);
 781         fp = fopen(fname, "r");
 782         if (!fp) {
 783                 die("Cannot open %s: %s\n",
 784                         fname, strerror(errno));
 785         }
 786         read_ehdr(fp);
 787         read_shdrs(fp);
 788         read_strtabs(fp);
 789         read_symtabs(fp);
 790         read_relocs(fp);
 791         if (show_absolute_syms) {
 792                 print_absolute_symbols();
 793                 return 0;
 794         }
 795         if (show_absolute_relocs) {
 796                 print_absolute_relocs();
 797                 return 0;
 798         }
 799         emit_relocs(as_text, use_real_mode);
 800         return 0;
 801 }