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         "^(__init_(begin|end)|"
  59         "__x86_cpu_dev_(start|end)|"
  60         "(__parainstructions|__alt_instructions)(|_end)|"
  61         "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
  62         "_end)$"
  63 };
  64
  65
  66 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  67 /*
  68  * These are 16-bit segment symbols when compiling 16-bit code.
  69  */
  70         [S_SEG] =
  71         "^real_mode_seg$",
  72
  73 /*
  74  * These are offsets belonging to segments, as opposed to linear addresses,
  75  * when compiling 16-bit code.
  76  */
  77         [S_LIN] =
  78         "^pa_",
  79 };
  80
  81 static const char * const *sym_regex;
  82
  83 static regex_t sym_regex_c[S_NSYMTYPES];
  84 static int is_reloc(enum symtype type, const char *sym_name)
  85 {
  86         return sym_regex[type] &&
  87                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
  88 }
  89
  90 static void regex_init(int use_real_mode)
  91 {
  92         char errbuf[128];
  93         int err;
  94         int i;
  95
  96         if (use_real_mode)
  97                 sym_regex = sym_regex_realmode;
  98         else
  99                 sym_regex = sym_regex_kernel;
 100
 101         for (i = 0; i < S_NSYMTYPES; i++) {
 102                 if (!sym_regex[i])
 103                         continue;
 104
 105                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 106                               REG_EXTENDED|REG_NOSUB);
 107
 108                 if (err) {
 109                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 110                         die("%s", errbuf);
 111                 }
 112         }
 113 }
 114
 115 static void die(char *fmt, ...)
 116 {
 117         va_list ap;
 118         va_start(ap, fmt);
 119         vfprintf(stderr, fmt, ap);
 120         va_end(ap);
 121         exit(1);
 122 }
 123
 124 static const char *sym_type(unsigned type)
 125 {
 126         static const char *type_name[] = {
 127 #define SYM_TYPE(X) [X] = #X
 128                 SYM_TYPE(STT_NOTYPE),
 129                 SYM_TYPE(STT_OBJECT),
 130                 SYM_TYPE(STT_FUNC),
 131                 SYM_TYPE(STT_SECTION),
 132                 SYM_TYPE(STT_FILE),
 133                 SYM_TYPE(STT_COMMON),
 134                 SYM_TYPE(STT_TLS),
 135 #undef SYM_TYPE
 136         };
 137         const char *name = "unknown sym type name";
 138         if (type < ARRAY_SIZE(type_name)) {
 139                 name = type_name[type];
 140         }
 141         return name;
 142 }
 143
 144 static const char *sym_bind(unsigned bind)
 145 {
 146         static const char *bind_name[] = {
 147 #define SYM_BIND(X) [X] = #X
 148                 SYM_BIND(STB_LOCAL),
 149                 SYM_BIND(STB_GLOBAL),
 150                 SYM_BIND(STB_WEAK),
 151 #undef SYM_BIND
 152         };
 153         const char *name = "unknown sym bind name";
 154         if (bind < ARRAY_SIZE(bind_name)) {
 155                 name = bind_name[bind];
 156         }
 157         return name;
 158 }
 159
 160 static const char *sym_visibility(unsigned visibility)
 161 {
 162         static const char *visibility_name[] = {
 163 #define SYM_VISIBILITY(X) [X] = #X
 164                 SYM_VISIBILITY(STV_DEFAULT),
 165                 SYM_VISIBILITY(STV_INTERNAL),
 166                 SYM_VISIBILITY(STV_HIDDEN),
 167                 SYM_VISIBILITY(STV_PROTECTED),
 168 #undef SYM_VISIBILITY
 169         };
 170         const char *name = "unknown sym visibility name";
 171         if (visibility < ARRAY_SIZE(visibility_name)) {
 172                 name = visibility_name[visibility];
 173         }
 174         return name;
 175 }
 176
 177 static const char *rel_type(unsigned type)
 178 {
 179         static const char *type_name[] = {
 180 #define REL_TYPE(X) [X] = #X
 181                 REL_TYPE(R_386_NONE),
 182                 REL_TYPE(R_386_32),
 183                 REL_TYPE(R_386_PC32),
 184                 REL_TYPE(R_386_GOT32),
 185                 REL_TYPE(R_386_PLT32),
 186                 REL_TYPE(R_386_COPY),
 187                 REL_TYPE(R_386_GLOB_DAT),
 188                 REL_TYPE(R_386_JMP_SLOT),
 189                 REL_TYPE(R_386_RELATIVE),
 190                 REL_TYPE(R_386_GOTOFF),
 191                 REL_TYPE(R_386_GOTPC),
 192                 REL_TYPE(R_386_8),
 193                 REL_TYPE(R_386_PC8),
 194                 REL_TYPE(R_386_16),
 195                 REL_TYPE(R_386_PC16),
 196 #undef REL_TYPE
 197         };
 198         const char *name = "unknown type rel type name";
 199         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 200                 name = type_name[type];
 201         }
 202         return name;
 203 }
 204
 205 static const char *sec_name(unsigned shndx)
 206 {
 207         const char *sec_strtab;
 208         const char *name;
 209         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 210         name = "<noname>";
 211         if (shndx < ehdr.e_shnum) {
 212                 name = sec_strtab + secs[shndx].shdr.sh_name;
 213         }
 214         else if (shndx == SHN_ABS) {
 215                 name = "ABSOLUTE";
 216         }
 217         else if (shndx == SHN_COMMON) {
 218                 name = "COMMON";
 219         }
 220         return name;
 221 }
 222
 223 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 224 {
 225         const char *name;
 226         name = "<noname>";
 227         if (sym->st_name) {
 228                 name = sym_strtab + sym->st_name;
 229         }
 230         else {
 231                 name = sec_name(sym->st_shndx);
 232         }
 233         return name;
 234 }
 235
 236
 237
 238 #if BYTE_ORDER == LITTLE_ENDIAN
 239 #define le16_to_cpu(val) (val)
 240 #define le32_to_cpu(val) (val)
 241 #endif
 242 #if BYTE_ORDER == BIG_ENDIAN
 243 #define le16_to_cpu(val) bswap_16(val)
 244 #define le32_to_cpu(val) bswap_32(val)
 245 #endif
 246
 247 static uint16_t elf16_to_cpu(uint16_t val)
 248 {
 249         return le16_to_cpu(val);
 250 }
 251
 252 static uint32_t elf32_to_cpu(uint32_t val)
 253 {
 254         return le32_to_cpu(val);
 255 }
 256
 257 static void read_ehdr(FILE *fp)
 258 {
 259         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 260                 die("Cannot read ELF header: %s\n",
 261                         strerror(errno));
 262         }
 263         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 264                 die("No ELF magic\n");
 265         }
 266         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 267                 die("Not a 32 bit executable\n");
 268         }
 269         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 270                 die("Not a LSB ELF executable\n");
 271         }
 272         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 273                 die("Unknown ELF version\n");
 274         }
 275         /* Convert the fields to native endian */
 276         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 277         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 278         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 279         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 280         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 281         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 282         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 283         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 284         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 285         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 286         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 287         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 288         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 289
 290         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 291                 die("Unsupported ELF header type\n");
 292         }
 293         if (ehdr.e_machine != EM_386) {
 294                 die("Not for x86\n");
 295         }
 296         if (ehdr.e_version != EV_CURRENT) {
 297                 die("Unknown ELF version\n");
 298         }
 299         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 300                 die("Bad Elf header size\n");
 301         }
 302         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 303                 die("Bad program header entry\n");
 304         }
 305         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 306                 die("Bad section header entry\n");
 307         }
 308         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 309                 die("String table index out of bounds\n");
 310         }
 311 }
 312
 313 static void read_shdrs(FILE *fp)
 314 {
 315         int i;
 316         Elf32_Shdr shdr;
 317
 318         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 319         if (!secs) {
 320                 die("Unable to allocate %d section headers\n",
 321                     ehdr.e_shnum);
 322         }
 323         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 324                 die("Seek to %d failed: %s\n",
 325                         ehdr.e_shoff, strerror(errno));
 326         }
 327         for (i = 0; i < ehdr.e_shnum; i++) {
 328                 struct section *sec = &secs[i];
 329                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 330                         die("Cannot read ELF section headers %d/%d: %s\n",
 331                             i, ehdr.e_shnum, strerror(errno));
 332                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 333                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 334                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 335                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 336                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 337                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 338                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 339                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 340                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 341                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 342                 if (sec->shdr.sh_link < ehdr.e_shnum)
 343                         sec->link = &secs[sec->shdr.sh_link];
 344         }
 345
 346 }
 347
 348 static void read_strtabs(FILE *fp)
 349 {
 350         int i;
 351         for (i = 0; i < ehdr.e_shnum; i++) {
 352                 struct section *sec = &secs[i];
 353                 if (sec->shdr.sh_type != SHT_STRTAB) {
 354                         continue;
 355                 }
 356                 sec->strtab = malloc(sec->shdr.sh_size);
 357                 if (!sec->strtab) {
 358                         die("malloc of %d bytes for strtab failed\n",
 359                                 sec->shdr.sh_size);
 360                 }
 361                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 362                         die("Seek to %d failed: %s\n",
 363                                 sec->shdr.sh_offset, strerror(errno));
 364                 }
 365                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 366                     != sec->shdr.sh_size) {
 367                         die("Cannot read symbol table: %s\n",
 368                                 strerror(errno));
 369                 }
 370         }
 371 }
 372
 373 static void read_symtabs(FILE *fp)
 374 {
 375         int i,j;
 376         for (i = 0; i < ehdr.e_shnum; i++) {
 377                 struct section *sec = &secs[i];
 378                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 379                         continue;
 380                 }
 381                 sec->symtab = malloc(sec->shdr.sh_size);
 382                 if (!sec->symtab) {
 383                         die("malloc of %d bytes for symtab failed\n",
 384                                 sec->shdr.sh_size);
 385                 }
 386                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 387                         die("Seek to %d failed: %s\n",
 388                                 sec->shdr.sh_offset, strerror(errno));
 389                 }
 390                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 391                     != sec->shdr.sh_size) {
 392                         die("Cannot read symbol table: %s\n",
 393                                 strerror(errno));
 394                 }
 395                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 396                         Elf32_Sym *sym = &sec->symtab[j];
 397                         sym->st_name  = elf32_to_cpu(sym->st_name);
 398                         sym->st_value = elf32_to_cpu(sym->st_value);
 399                         sym->st_size  = elf32_to_cpu(sym->st_size);
 400                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 401                 }
 402         }
 403 }
 404
 405
 406 static void read_relocs(FILE *fp)
 407 {
 408         int i,j;
 409         for (i = 0; i < ehdr.e_shnum; i++) {
 410                 struct section *sec = &secs[i];
 411                 if (sec->shdr.sh_type != SHT_REL) {
 412                         continue;
 413                 }
 414                 sec->reltab = malloc(sec->shdr.sh_size);
 415                 if (!sec->reltab) {
 416                         die("malloc of %d bytes for relocs failed\n",
 417                                 sec->shdr.sh_size);
 418                 }
 419                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 420                         die("Seek to %d failed: %s\n",
 421                                 sec->shdr.sh_offset, strerror(errno));
 422                 }
 423                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 424                     != sec->shdr.sh_size) {
 425                         die("Cannot read symbol table: %s\n",
 426                                 strerror(errno));
 427                 }
 428                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 429                         Elf32_Rel *rel = &sec->reltab[j];
 430                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 431                         rel->r_info   = elf32_to_cpu(rel->r_info);
 432                 }
 433         }
 434 }
 435
 436
 437 static void print_absolute_symbols(void)
 438 {
 439         int i;
 440         printf("Absolute symbols\n");
 441         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 442         for (i = 0; i < ehdr.e_shnum; i++) {
 443                 struct section *sec = &secs[i];
 444                 char *sym_strtab;
 445                 int j;
 446
 447                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 448                         continue;
 449                 }
 450                 sym_strtab = sec->link->strtab;
 451                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 452                         Elf32_Sym *sym;
 453                         const char *name;
 454                         sym = &sec->symtab[j];
 455                         name = sym_name(sym_strtab, sym);
 456                         if (sym->st_shndx != SHN_ABS) {
 457                                 continue;
 458                         }
 459                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 460                                 j, sym->st_value, sym->st_size,
 461                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 462                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 463                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 464                                 name);
 465                 }
 466         }
 467         printf("\n");
 468 }
 469
 470 static void print_absolute_relocs(void)
 471 {
 472         int i, printed = 0;
 473
 474         for (i = 0; i < ehdr.e_shnum; i++) {
 475                 struct section *sec = &secs[i];
 476                 struct section *sec_applies, *sec_symtab;
 477                 char *sym_strtab;
 478                 Elf32_Sym *sh_symtab;
 479                 int j;
 480                 if (sec->shdr.sh_type != SHT_REL) {
 481                         continue;
 482                 }
 483                 sec_symtab  = sec->link;
 484                 sec_applies = &secs[sec->shdr.sh_info];
 485                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 486                         continue;
 487                 }
 488                 sh_symtab  = sec_symtab->symtab;
 489                 sym_strtab = sec_symtab->link->strtab;
 490                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 491                         Elf32_Rel *rel;
 492                         Elf32_Sym *sym;
 493                         const char *name;
 494                         rel = &sec->reltab[j];
 495                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 496                         name = sym_name(sym_strtab, sym);
 497                         if (sym->st_shndx != SHN_ABS) {
 498                                 continue;
 499                         }
 500
 501                         /* Absolute symbols are not relocated if bzImage is
 502                          * loaded at a non-compiled address. Display a warning
 503                          * to user at compile time about the absolute
 504                          * relocations present.
 505                          *
 506                          * User need to audit the code to make sure
 507                          * some symbols which should have been section
 508                          * relative have not become absolute because of some
 509                          * linker optimization or wrong programming usage.
 510                          *
 511                          * Before warning check if this absolute symbol
 512                          * relocation is harmless.
 513                          */
 514                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 515                                 continue;
 516
 517                         if (!printed) {
 518                                 printf("WARNING: Absolute relocations"
 519                                         " present\n");
 520                                 printf("Offset     Info     Type     Sym.Value "
 521                                         "Sym.Name\n");
 522                                 printed = 1;
 523                         }
 524
 525                         printf("%08x %08x %10s %08x  %s\n",
 526                                 rel->r_offset,
 527                                 rel->r_info,
 528                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 529                                 sym->st_value,
 530                                 name);
 531                 }
 532         }
 533
 534         if (printed)
 535                 printf("\n");
 536 }
 537
 538 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 539                         int use_real_mode)
 540 {
 541         int i;
 542         /* Walk through the relocations */
 543         for (i = 0; i < ehdr.e_shnum; i++) {
 544                 char *sym_strtab;
 545                 Elf32_Sym *sh_symtab;
 546                 struct section *sec_applies, *sec_symtab;
 547                 int j;
 548                 struct section *sec = &secs[i];
 549
 550                 if (sec->shdr.sh_type != SHT_REL) {
 551                         continue;
 552                 }
 553                 sec_symtab  = sec->link;
 554                 sec_applies = &secs[sec->shdr.sh_info];
 555                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 556                         continue;
 557                 }
 558                 sh_symtab = sec_symtab->symtab;
 559                 sym_strtab = sec_symtab->link->strtab;
 560                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 561                         Elf32_Rel *rel;
 562                         Elf32_Sym *sym;
 563                         unsigned r_type;
 564                         const char *symname;
 565                         int shn_abs;
 566
 567                         rel = &sec->reltab[j];
 568                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 569                         r_type = ELF32_R_TYPE(rel->r_info);
 570
 571                         shn_abs = sym->st_shndx == SHN_ABS;
 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 (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 (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 %s relocation: %s\n",
 623                                     shn_abs ? "absolute" : "relative",
 624                                     rel_type(r_type), symname);
 625                         }
 626                 }
 627         }
 628 }
 629
 630 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 631 {
 632         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 633                 reloc16_count++;
 634         else
 635                 reloc_count++;
 636 }
 637
 638 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 639 {
 640         /* Remember the address that needs to be adjusted. */
 641         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 642                 relocs16[reloc16_idx++] = rel->r_offset;
 643         else
 644                 relocs[reloc_idx++] = rel->r_offset;
 645 }
 646
 647 static int cmp_relocs(const void *va, const void *vb)
 648 {
 649         const unsigned long *a, *b;
 650         a = va; b = vb;
 651         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 652 }
 653
 654 static int write32(unsigned int v, FILE *f)
 655 {
 656         unsigned char buf[4];
 657
 658         buf[0] = (v >>  0) & 0xff;
 659         buf[1] = (v >>  8) & 0xff;
 660         buf[2] = (v >> 16) & 0xff;
 661         buf[3] = (v >> 24) & 0xff;
 662         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 663 }
 664
 665 static void emit_relocs(int as_text, int use_real_mode)
 666 {
 667         int i;
 668         /* Count how many relocations I have and allocate space for them. */
 669         reloc_count = 0;
 670         walk_relocs(count_reloc, use_real_mode);
 671         relocs = malloc(reloc_count * sizeof(relocs[0]));
 672         if (!relocs) {
 673                 die("malloc of %d entries for relocs failed\n",
 674                         reloc_count);
 675         }
 676
 677         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 678         if (!relocs16) {
 679                 die("malloc of %d entries for relocs16 failed\n",
 680                         reloc16_count);
 681         }
 682         /* Collect up the relocations */
 683         reloc_idx = 0;
 684         walk_relocs(collect_reloc, use_real_mode);
 685
 686         if (reloc16_count && !use_real_mode)
 687                 die("Segment relocations found but --realmode not specified\n");
 688
 689         /* Order the relocations for more efficient processing */
 690         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 691         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 692
 693         /* Print the relocations */
 694         if (as_text) {
 695                 /* Print the relocations in a form suitable that
 696                  * gas will like.
 697                  */
 698                 printf(".section \".data.reloc\",\"a\"\n");
 699                 printf(".balign 4\n");
 700                 if (use_real_mode) {
 701                         printf("\t.long %lu\n", reloc16_count);
 702                         for (i = 0; i < reloc16_count; i++)
 703                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 704                         printf("\t.long %lu\n", reloc_count);
 705                         for (i = 0; i < reloc_count; i++) {
 706                                 printf("\t.long 0x%08lx\n", relocs[i]);
 707                         }
 708                 } else {
 709                         /* Print a stop */
 710                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 711                         for (i = 0; i < reloc_count; i++) {
 712                                 printf("\t.long 0x%08lx\n", relocs[i]);
 713                         }
 714                 }
 715
 716                 printf("\n");
 717         }
 718         else {
 719                 if (use_real_mode) {
 720                         write32(reloc16_count, stdout);
 721                         for (i = 0; i < reloc16_count; i++)
 722                                 write32(relocs16[i], stdout);
 723                         write32(reloc_count, stdout);
 724
 725                         /* Now print each relocation */
 726                         for (i = 0; i < reloc_count; i++)
 727                                 write32(relocs[i], stdout);
 728                 } else {
 729                         /* Print a stop */
 730                         write32(0, stdout);
 731
 732                         /* Now print each relocation */
 733                         for (i = 0; i < reloc_count; i++) {
 734                                 write32(relocs[i], stdout);
 735                         }
 736                 }
 737         }
 738 }
 739
 740 static void usage(void)
 741 {
 742         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 743 }
 744
 745 int main(int argc, char **argv)
 746 {
 747         int show_absolute_syms, show_absolute_relocs;
 748         int as_text, use_real_mode;
 749         const char *fname;
 750         FILE *fp;
 751         int i;
 752
 753         show_absolute_syms = 0;
 754         show_absolute_relocs = 0;
 755         as_text = 0;
 756         use_real_mode = 0;
 757         fname = NULL;
 758         for (i = 1; i < argc; i++) {
 759                 char *arg = argv[i];
 760                 if (*arg == '-') {
 761                         if (strcmp(arg, "--abs-syms") == 0) {
 762                                 show_absolute_syms = 1;
 763                                 continue;
 764                         }
 765                         if (strcmp(arg, "--abs-relocs") == 0) {
 766                                 show_absolute_relocs = 1;
 767                                 continue;
 768                         }
 769                         if (strcmp(arg, "--text") == 0) {
 770                                 as_text = 1;
 771                                 continue;
 772                         }
 773                         if (strcmp(arg, "--realmode") == 0) {
 774                                 use_real_mode = 1;
 775                                 continue;
 776                         }
 777                 }
 778                 else if (!fname) {
 779                         fname = arg;
 780                         continue;
 781                 }
 782                 usage();
 783         }
 784         if (!fname) {
 785                 usage();
 786         }
 787         regex_init(use_real_mode);
 788         fp = fopen(fname, "r");
 789         if (!fp) {
 790                 die("Cannot open %s: %s\n",
 791                         fname, strerror(errno));
 792         }
 793         read_ehdr(fp);
 794         read_shdrs(fp);
 795         read_strtabs(fp);
 796         read_symtabs(fp);
 797         read_relocs(fp);
 798         if (show_absolute_syms) {
 799                 print_absolute_symbols();
 800                 return 0;
 801         }
 802         if (show_absolute_relocs) {
 803                 print_absolute_relocs();
 804                 return 0;
 805         }
 806         emit_relocs(as_text, use_real_mode);
 807         return 0;
 808 }