scripts/mod/modpost.c

   1 /* Postprocess module symbol versions
   2  *
   3  * Copyright 2003       Kai Germaschewski
   4  * Copyright 2002-2004  Rusty Russell, IBM Corporation
   5  * Copyright 2006-2008  Sam Ravnborg
   6  * Based in part on module-init-tools/depmod.c,file2alias
   7  *
   8  * This software may be used and distributed according to the terms
   9  * of the GNU General Public License, incorporated herein by reference.
  10  *
  11  * Usage: modpost vmlinux module1.o module2.o ...
  12  */
  13
  14 #define _GNU_SOURCE
  15 #include <stdio.h>
  16 #include <ctype.h>
  17 #include <string.h>
  18 #include <limits.h>
  19 #include <stdbool.h>
  20 #include <errno.h>
  21 #include "modpost.h"
  22 #include "../../include/generated/autoconf.h"
  23 #include "../../include/linux/license.h"
  24 #include "../../include/linux/export.h"
  25
  26 /* Are we using CONFIG_MODVERSIONS? */
  27 static int modversions = 0;
  28 /* Warn about undefined symbols? (do so if we have vmlinux) */
  29 static int have_vmlinux = 0;
  30 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  31 static int all_versions = 0;
  32 /* If we are modposting external module set to 1 */
  33 static int external_module = 0;
  34 /* Warn about section mismatch in vmlinux if set to 1 */
  35 static int vmlinux_section_warnings = 1;
  36 /* Only warn about unresolved symbols */
  37 static int warn_unresolved = 0;
  38 /* How a symbol is exported */
  39 static int sec_mismatch_count = 0;
  40 static int sec_mismatch_verbose = 1;
  41 static int sec_mismatch_fatal = 0;
  42 /* ignore missing files */
  43 static int ignore_missing_files;
  44
  45 enum export {
  46         export_plain,      export_unused,     export_gpl,
  47         export_unused_gpl, export_gpl_future, export_unknown
  48 };
  49
  50 /* In kernel, this size is defined in linux/module.h;
  51  * here we use Elf_Addr instead of long for covering cross-compile
  52  */
  53
  54 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
  55
  56 #define PRINTF __attribute__ ((format (printf, 1, 2)))
  57
  58 PRINTF void fatal(const char *fmt, ...)
  59 {
  60         va_list arglist;
  61
  62         fprintf(stderr, "FATAL: ");
  63
  64         va_start(arglist, fmt);
  65         vfprintf(stderr, fmt, arglist);
  66         va_end(arglist);
  67
  68         exit(1);
  69 }
  70
  71 PRINTF void warn(const char *fmt, ...)
  72 {
  73         va_list arglist;
  74
  75         fprintf(stderr, "WARNING: ");
  76
  77         va_start(arglist, fmt);
  78         vfprintf(stderr, fmt, arglist);
  79         va_end(arglist);
  80 }
  81
  82 PRINTF void merror(const char *fmt, ...)
  83 {
  84         va_list arglist;
  85
  86         fprintf(stderr, "ERROR: ");
  87
  88         va_start(arglist, fmt);
  89         vfprintf(stderr, fmt, arglist);
  90         va_end(arglist);
  91 }
  92
  93 static inline bool strends(const char *str, const char *postfix)
  94 {
  95         if (strlen(str) < strlen(postfix))
  96                 return false;
  97
  98         return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
  99 }
 100
 101 static int is_vmlinux(const char *modname)
 102 {
 103         const char *myname;
 104
 105         myname = strrchr(modname, '/');
 106         if (myname)
 107                 myname++;
 108         else
 109                 myname = modname;
 110
 111         return (strcmp(myname, "vmlinux") == 0) ||
 112                (strcmp(myname, "vmlinux.o") == 0);
 113 }
 114
 115 void *do_nofail(void *ptr, const char *expr)
 116 {
 117         if (!ptr)
 118                 fatal("modpost: Memory allocation failure: %s.\n", expr);
 119
 120         return ptr;
 121 }
 122
 123 /* A list of all modules we processed */
 124 static struct module *modules;
 125
 126 static struct module *find_module(char *modname)
 127 {
 128         struct module *mod;
 129
 130         for (mod = modules; mod; mod = mod->next)
 131                 if (strcmp(mod->name, modname) == 0)
 132                         break;
 133         return mod;
 134 }
 135
 136 static struct module *new_module(const char *modname)
 137 {
 138         struct module *mod;
 139         char *p;
 140
 141         mod = NOFAIL(malloc(sizeof(*mod)));
 142         memset(mod, 0, sizeof(*mod));
 143         p = NOFAIL(strdup(modname));
 144
 145         /* strip trailing .o */
 146         if (strends(p, ".o")) {
 147                 p[strlen(p) - 2] = '\0';
 148                 mod->is_dot_o = 1;
 149         }
 150
 151         /* add to list */
 152         mod->name = p;
 153         mod->gpl_compatible = -1;
 154         mod->next = modules;
 155         modules = mod;
 156
 157         return mod;
 158 }
 159
 160 /* A hash of all exported symbols,
 161  * struct symbol is also used for lists of unresolved symbols */
 162
 163 #define SYMBOL_HASH_SIZE 1024
 164
 165 struct symbol {
 166         struct symbol *next;
 167         struct module *module;
 168         unsigned int crc;
 169         int crc_valid;
 170         unsigned int weak:1;
 171         unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 172         unsigned int kernel:1;     /* 1 if symbol is from kernel
 173                                     *  (only for external modules) **/
 174         unsigned int preloaded:1;  /* 1 if symbol from Module.symvers, or crc */
 175         enum export  export;       /* Type of export */
 176         char name[0];
 177 };
 178
 179 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 180
 181 /* This is based on the hash agorithm from gdbm, via tdb */
 182 static inline unsigned int tdb_hash(const char *name)
 183 {
 184         unsigned value; /* Used to compute the hash value.  */
 185         unsigned   i;   /* Used to cycle through random values. */
 186
 187         /* Set the initial value from the key size. */
 188         for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 189                 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 190
 191         return (1103515243 * value + 12345);
 192 }
 193
 194 /**
 195  * Allocate a new symbols for use in the hash of exported symbols or
 196  * the list of unresolved symbols per module
 197  **/
 198 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
 199                                    struct symbol *next)
 200 {
 201         struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 202
 203         memset(s, 0, sizeof(*s));
 204         strcpy(s->name, name);
 205         s->weak = weak;
 206         s->next = next;
 207         return s;
 208 }
 209
 210 /* For the hash of exported symbols */
 211 static struct symbol *new_symbol(const char *name, struct module *module,
 212                                  enum export export)
 213 {
 214         unsigned int hash;
 215         struct symbol *new;
 216
 217         hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
 218         new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
 219         new->module = module;
 220         new->export = export;
 221         return new;
 222 }
 223
 224 static struct symbol *find_symbol(const char *name)
 225 {
 226         struct symbol *s;
 227
 228         /* For our purposes, .foo matches foo.  PPC64 needs this. */
 229         if (name[0] == '.')
 230                 name++;
 231
 232         for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 233                 if (strcmp(s->name, name) == 0)
 234                         return s;
 235         }
 236         return NULL;
 237 }
 238
 239 static const struct {
 240         const char *str;
 241         enum export export;
 242 } export_list[] = {
 243         { .str = "EXPORT_SYMBOL",            .export = export_plain },
 244         { .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 245         { .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 246         { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 247         { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 248         { .str = "(unknown)",                .export = export_unknown },
 249 };
 250
 251
 252 static const char *export_str(enum export ex)
 253 {
 254         return export_list[ex].str;
 255 }
 256
 257 static enum export export_no(const char *s)
 258 {
 259         int i;
 260
 261         if (!s)
 262                 return export_unknown;
 263         for (i = 0; export_list[i].export != export_unknown; i++) {
 264                 if (strcmp(export_list[i].str, s) == 0)
 265                         return export_list[i].export;
 266         }
 267         return export_unknown;
 268 }
 269
 270 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
 271 {
 272         return (void *)elf->hdr +
 273                 elf->sechdrs[elf->secindex_strings].sh_offset +
 274                 sechdr->sh_name;
 275 }
 276
 277 static const char *sec_name(struct elf_info *elf, int secindex)
 278 {
 279         return sech_name(elf, &elf->sechdrs[secindex]);
 280 }
 281
 282 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 283
 284 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 285 {
 286         const char *secname = sec_name(elf, sec);
 287
 288         if (strstarts(secname, "___ksymtab+"))
 289                 return export_plain;
 290         else if (strstarts(secname, "___ksymtab_unused+"))
 291                 return export_unused;
 292         else if (strstarts(secname, "___ksymtab_gpl+"))
 293                 return export_gpl;
 294         else if (strstarts(secname, "___ksymtab_unused_gpl+"))
 295                 return export_unused_gpl;
 296         else if (strstarts(secname, "___ksymtab_gpl_future+"))
 297                 return export_gpl_future;
 298         else
 299                 return export_unknown;
 300 }
 301
 302 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 303 {
 304         if (sec == elf->export_sec)
 305                 return export_plain;
 306         else if (sec == elf->export_unused_sec)
 307                 return export_unused;
 308         else if (sec == elf->export_gpl_sec)
 309                 return export_gpl;
 310         else if (sec == elf->export_unused_gpl_sec)
 311                 return export_unused_gpl;
 312         else if (sec == elf->export_gpl_future_sec)
 313                 return export_gpl_future;
 314         else
 315                 return export_unknown;
 316 }
 317
 318 /**
 319  * Add an exported symbol - it may have already been added without a
 320  * CRC, in this case just update the CRC
 321  **/
 322 static struct symbol *sym_add_exported(const char *name, struct module *mod,
 323                                        enum export export)
 324 {
 325         struct symbol *s = find_symbol(name);
 326
 327         if (!s) {
 328                 s = new_symbol(name, mod, export);
 329         } else {
 330                 if (!s->preloaded) {
 331                         warn("%s: '%s' exported twice. Previous export "
 332                              "was in %s%s\n", mod->name, name,
 333                              s->module->name,
 334                              is_vmlinux(s->module->name) ?"":".ko");
 335                 } else {
 336                         /* In case Module.symvers was out of date */
 337                         s->module = mod;
 338                 }
 339         }
 340         s->preloaded = 0;
 341         s->vmlinux   = is_vmlinux(mod->name);
 342         s->kernel    = 0;
 343         s->export    = export;
 344         return s;
 345 }
 346
 347 static void sym_update_crc(const char *name, struct module *mod,
 348                            unsigned int crc, enum export export)
 349 {
 350         struct symbol *s = find_symbol(name);
 351
 352         if (!s) {
 353                 s = new_symbol(name, mod, export);
 354                 /* Don't complain when we find it later. */
 355                 s->preloaded = 1;
 356         }
 357         s->crc = crc;
 358         s->crc_valid = 1;
 359 }
 360
 361 void *grab_file(const char *filename, unsigned long *size)
 362 {
 363         struct stat st;
 364         void *map = MAP_FAILED;
 365         int fd;
 366
 367         fd = open(filename, O_RDONLY);
 368         if (fd < 0)
 369                 return NULL;
 370         if (fstat(fd, &st))
 371                 goto failed;
 372
 373         *size = st.st_size;
 374         map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 375
 376 failed:
 377         close(fd);
 378         if (map == MAP_FAILED)
 379                 return NULL;
 380         return map;
 381 }
 382
 383 /**
 384   * Return a copy of the next line in a mmap'ed file.
 385   * spaces in the beginning of the line is trimmed away.
 386   * Return a pointer to a static buffer.
 387   **/
 388 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
 389 {
 390         static char line[4096];
 391         int skip = 1;
 392         size_t len = 0;
 393         signed char *p = (signed char *)file + *pos;
 394         char *s = line;
 395
 396         for (; *pos < size ; (*pos)++) {
 397                 if (skip && isspace(*p)) {
 398                         p++;
 399                         continue;
 400                 }
 401                 skip = 0;
 402                 if (*p != '\n' && (*pos < size)) {
 403                         len++;
 404                         *s++ = *p++;
 405                         if (len > 4095)
 406                                 break; /* Too long, stop */
 407                 } else {
 408                         /* End of string */
 409                         *s = '\0';
 410                         return line;
 411                 }
 412         }
 413         /* End of buffer */
 414         return NULL;
 415 }
 416
 417 void release_file(void *file, unsigned long size)
 418 {
 419         munmap(file, size);
 420 }
 421
 422 static int parse_elf(struct elf_info *info, const char *filename)
 423 {
 424         unsigned int i;
 425         Elf_Ehdr *hdr;
 426         Elf_Shdr *sechdrs;
 427         Elf_Sym  *sym;
 428         const char *secstrings;
 429         unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 430
 431         hdr = grab_file(filename, &info->size);
 432         if (!hdr) {
 433                 if (ignore_missing_files) {
 434                         fprintf(stderr, "%s: %s (ignored)\n", filename,
 435                                 strerror(errno));
 436                         return 0;
 437                 }
 438                 perror(filename);
 439                 exit(1);
 440         }
 441         info->hdr = hdr;
 442         if (info->size < sizeof(*hdr)) {
 443                 /* file too small, assume this is an empty .o file */
 444                 return 0;
 445         }
 446         /* Is this a valid ELF file? */
 447         if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 448             (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 449             (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 450             (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 451                 /* Not an ELF file - silently ignore it */
 452                 return 0;
 453         }
 454         /* Fix endianness in ELF header */
 455         hdr->e_type      = TO_NATIVE(hdr->e_type);
 456         hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 457         hdr->e_version   = TO_NATIVE(hdr->e_version);
 458         hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 459         hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 460         hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 461         hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 462         hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 463         hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 464         hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 465         hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 466         hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 467         hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 468         sechdrs = (void *)hdr + hdr->e_shoff;
 469         info->sechdrs = sechdrs;
 470
 471         /* Check if file offset is correct */
 472         if (hdr->e_shoff > info->size) {
 473                 fatal("section header offset=%lu in file '%s' is bigger than "
 474                       "filesize=%lu\n", (unsigned long)hdr->e_shoff,
 475                       filename, info->size);
 476                 return 0;
 477         }
 478
 479         if (hdr->e_shnum == SHN_UNDEF) {
 480                 /*
 481                  * There are more than 64k sections,
 482                  * read count from .sh_size.
 483                  */
 484                 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 485         }
 486         else {
 487                 info->num_sections = hdr->e_shnum;
 488         }
 489         if (hdr->e_shstrndx == SHN_XINDEX) {
 490                 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
 491         }
 492         else {
 493                 info->secindex_strings = hdr->e_shstrndx;
 494         }
 495
 496         /* Fix endianness in section headers */
 497         for (i = 0; i < info->num_sections; i++) {
 498                 sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 499                 sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 500                 sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 501                 sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 502                 sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 503                 sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 504                 sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 505                 sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 506                 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 507                 sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 508         }
 509         /* Find symbol table. */
 510         secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 511         for (i = 1; i < info->num_sections; i++) {
 512                 const char *secname;
 513                 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 514
 515                 if (!nobits && sechdrs[i].sh_offset > info->size) {
 516                         fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
 517                               "sizeof(*hrd)=%zu\n", filename,
 518                               (unsigned long)sechdrs[i].sh_offset,
 519                               sizeof(*hdr));
 520                         return 0;
 521                 }
 522                 secname = secstrings + sechdrs[i].sh_name;
 523                 if (strcmp(secname, ".modinfo") == 0) {
 524                         if (nobits)
 525                                 fatal("%s has NOBITS .modinfo\n", filename);
 526                         info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 527                         info->modinfo_len = sechdrs[i].sh_size;
 528                 } else if (strcmp(secname, "__ksymtab") == 0)
 529                         info->export_sec = i;
 530                 else if (strcmp(secname, "__ksymtab_unused") == 0)
 531                         info->export_unused_sec = i;
 532                 else if (strcmp(secname, "__ksymtab_gpl") == 0)
 533                         info->export_gpl_sec = i;
 534                 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 535                         info->export_unused_gpl_sec = i;
 536                 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
 537                         info->export_gpl_future_sec = i;
 538
 539                 if (sechdrs[i].sh_type == SHT_SYMTAB) {
 540                         unsigned int sh_link_idx;
 541                         symtab_idx = i;
 542                         info->symtab_start = (void *)hdr +
 543                             sechdrs[i].sh_offset;
 544                         info->symtab_stop  = (void *)hdr +
 545                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 546                         sh_link_idx = sechdrs[i].sh_link;
 547                         info->strtab       = (void *)hdr +
 548                             sechdrs[sh_link_idx].sh_offset;
 549                 }
 550
 551                 /* 32bit section no. table? ("more than 64k sections") */
 552                 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 553                         symtab_shndx_idx = i;
 554                         info->symtab_shndx_start = (void *)hdr +
 555                             sechdrs[i].sh_offset;
 556                         info->symtab_shndx_stop  = (void *)hdr +
 557                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 558                 }
 559         }
 560         if (!info->symtab_start)
 561                 fatal("%s has no symtab?\n", filename);
 562
 563         /* Fix endianness in symbols */
 564         for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 565                 sym->st_shndx = TO_NATIVE(sym->st_shndx);
 566                 sym->st_name  = TO_NATIVE(sym->st_name);
 567                 sym->st_value = TO_NATIVE(sym->st_value);
 568                 sym->st_size  = TO_NATIVE(sym->st_size);
 569         }
 570
 571         if (symtab_shndx_idx != ~0U) {
 572                 Elf32_Word *p;
 573                 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
 574                         fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 575                               filename, sechdrs[symtab_shndx_idx].sh_link,
 576                               symtab_idx);
 577                 /* Fix endianness */
 578                 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 579                      p++)
 580                         *p = TO_NATIVE(*p);
 581         }
 582
 583         return 1;
 584 }
 585
 586 static void parse_elf_finish(struct elf_info *info)
 587 {
 588         release_file(info->hdr, info->size);
 589 }
 590
 591 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 592 {
 593         /* ignore __this_module, it will be resolved shortly */
 594         if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
 595                 return 1;
 596         /* ignore global offset table */
 597         if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 598                 return 1;
 599         if (info->hdr->e_machine == EM_PPC)
 600                 /* Special register function linked on all modules during final link of .ko */
 601                 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
 602                     strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
 603                     strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
 604                     strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
 605                     strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
 606                     strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
 607                         return 1;
 608         if (info->hdr->e_machine == EM_PPC64)
 609                 /* Special register function linked on all modules during final link of .ko */
 610                 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
 611                     strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
 612                     strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
 613                     strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
 614                     strcmp(symname, ".TOC.") == 0)
 615                         return 1;
 616         /* Do not ignore this symbol */
 617         return 0;
 618 }
 619
 620 #define CRC_PFX     VMLINUX_SYMBOL_STR(__crc_)
 621 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
 622
 623 static void handle_modversions(struct module *mod, struct elf_info *info,
 624                                Elf_Sym *sym, const char *symname)
 625 {
 626         unsigned int crc;
 627         enum export export;
 628         bool is_crc = false;
 629
 630         if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
 631             strncmp(symname, "__ksymtab", 9) == 0)
 632                 export = export_from_secname(info, get_secindex(info, sym));
 633         else
 634                 export = export_from_sec(info, get_secindex(info, sym));
 635
 636         /* CRC'd symbol */
 637         if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
 638                 is_crc = true;
 639                 crc = (unsigned int) sym->st_value;
 640                 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
 641                         unsigned int *crcp;
 642
 643                         /* symbol points to the CRC in the ELF object */
 644                         crcp = (void *)info->hdr + sym->st_value +
 645                                info->sechdrs[sym->st_shndx].sh_offset -
 646                                (info->hdr->e_type != ET_REL ?
 647                                 info->sechdrs[sym->st_shndx].sh_addr : 0);
 648                         crc = *crcp;
 649                 }
 650                 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
 651                                 export);
 652         }
 653
 654         switch (sym->st_shndx) {
 655         case SHN_COMMON:
 656                 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
 657                         /* Should warn here, but modpost runs before the linker */
 658                 } else
 659                         warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 660                 break;
 661         case SHN_UNDEF:
 662                 /* undefined symbol */
 663                 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 664                     ELF_ST_BIND(sym->st_info) != STB_WEAK)
 665                         break;
 666                 if (ignore_undef_symbol(info, symname))
 667                         break;
 668 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
 669 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
 670 /* add compatibility with older glibc */
 671 #ifndef STT_SPARC_REGISTER
 672 #define STT_SPARC_REGISTER STT_REGISTER
 673 #endif
 674                 if (info->hdr->e_machine == EM_SPARC ||
 675                     info->hdr->e_machine == EM_SPARCV9) {
 676                         /* Ignore register directives. */
 677                         if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 678                                 break;
 679                         if (symname[0] == '.') {
 680                                 char *munged = strdup(symname);
 681                                 munged[0] = '_';
 682                                 munged[1] = toupper(munged[1]);
 683                                 symname = munged;
 684                         }
 685                 }
 686 #endif
 687
 688 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
 689                 if (symname[0] != '_')
 690                         break;
 691                 else
 692                         symname++;
 693 #endif
 694                 if (is_crc) {
 695                         const char *e = is_vmlinux(mod->name) ?"":".ko";
 696                         warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
 697                 }
 698                 mod->unres = alloc_symbol(symname,
 699                                           ELF_ST_BIND(sym->st_info) == STB_WEAK,
 700                                           mod->unres);
 701                 break;
 702         default:
 703                 /* All exported symbols */
 704                 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
 705                         sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
 706                                         export);
 707                 }
 708                 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
 709                         mod->has_init = 1;
 710                 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
 711                         mod->has_cleanup = 1;
 712                 break;
 713         }
 714 }
 715
 716 /**
 717  * Parse tag=value strings from .modinfo section
 718  **/
 719 static char *next_string(char *string, unsigned long *secsize)
 720 {
 721         /* Skip non-zero chars */
 722         while (string[0]) {
 723                 string++;
 724                 if ((*secsize)-- <= 1)
 725                         return NULL;
 726         }
 727
 728         /* Skip any zero padding. */
 729         while (!string[0]) {
 730                 string++;
 731                 if ((*secsize)-- <= 1)
 732                         return NULL;
 733         }
 734         return string;
 735 }
 736
 737 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
 738                               const char *tag, char *info)
 739 {
 740         char *p;
 741         unsigned int taglen = strlen(tag);
 742         unsigned long size = modinfo_len;
 743
 744         if (info) {
 745                 size -= info - (char *)modinfo;
 746                 modinfo = next_string(info, &size);
 747         }
 748
 749         for (p = modinfo; p; p = next_string(p, &size)) {
 750                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 751                         return p + taglen + 1;
 752         }
 753         return NULL;
 754 }
 755
 756 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
 757                          const char *tag)
 758
 759 {
 760         return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
 761 }
 762
 763 /**
 764  * Test if string s ends in string sub
 765  * return 0 if match
 766  **/
 767 static int strrcmp(const char *s, const char *sub)
 768 {
 769         int slen, sublen;
 770
 771         if (!s || !sub)
 772                 return 1;
 773
 774         slen = strlen(s);
 775         sublen = strlen(sub);
 776
 777         if ((slen == 0) || (sublen == 0))
 778                 return 1;
 779
 780         if (sublen > slen)
 781                 return 1;
 782
 783         return memcmp(s + slen - sublen, sub, sublen);
 784 }
 785
 786 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 787 {
 788         if (sym)
 789                 return elf->strtab + sym->st_name;
 790         else
 791                 return "(unknown)";
 792 }
 793
 794 /* The pattern is an array of simple patterns.
 795  * "foo" will match an exact string equal to "foo"
 796  * "*foo" will match a string that ends with "foo"
 797  * "foo*" will match a string that begins with "foo"
 798  * "*foo*" will match a string that contains "foo"
 799  */
 800 static int match(const char *sym, const char * const pat[])
 801 {
 802         const char *p;
 803         while (*pat) {
 804                 p = *pat++;
 805                 const char *endp = p + strlen(p) - 1;
 806
 807                 /* "*foo*" */
 808                 if (*p == '*' && *endp == '*') {
 809                         char *here, *bare = strndup(p + 1, strlen(p) - 2);
 810
 811                         here = strstr(sym, bare);
 812                         free(bare);
 813                         if (here != NULL)
 814                                 return 1;
 815                 }
 816                 /* "*foo" */
 817                 else if (*p == '*') {
 818                         if (strrcmp(sym, p + 1) == 0)
 819                                 return 1;
 820                 }
 821                 /* "foo*" */
 822                 else if (*endp == '*') {
 823                         if (strncmp(sym, p, strlen(p) - 1) == 0)
 824                                 return 1;
 825                 }
 826                 /* no wildcards */
 827                 else {
 828                         if (strcmp(p, sym) == 0)
 829                                 return 1;
 830                 }
 831         }
 832         /* no match */
 833         return 0;
 834 }
 835
 836 /* sections that we do not want to do full section mismatch check on */
 837 static const char *const section_white_list[] =
 838 {
 839         ".comment*",
 840         ".debug*",
 841         ".cranges",             /* sh64 */
 842         ".zdebug*",             /* Compressed debug sections. */
 843         ".GCC-command-line",    /* mn10300 */
 844         ".GCC.command.line",    /* record-gcc-switches, non mn10300 */
 845         ".mdebug*",        /* alpha, score, mips etc. */
 846         ".pdr",            /* alpha, score, mips etc. */
 847         ".stab*",
 848         ".note*",
 849         ".got*",
 850         ".toc*",
 851         ".xt.prop",                              /* xtensa */
 852         ".xt.lit",         /* xtensa */
 853         ".arcextmap*",                  /* arc */
 854         ".gnu.linkonce.arcext*",        /* arc : modules */
 855         ".cmem*",                       /* EZchip */
 856         ".fmt_slot*",                   /* EZchip */
 857         ".gnu.lto*",
 858         ".discard.*",
 859         NULL
 860 };
 861
 862 /*
 863  * This is used to find sections missing the SHF_ALLOC flag.
 864  * The cause of this is often a section specified in assembler
 865  * without "ax" / "aw".
 866  */
 867 static void check_section(const char *modname, struct elf_info *elf,
 868                           Elf_Shdr *sechdr)
 869 {
 870         const char *sec = sech_name(elf, sechdr);
 871
 872         if (sechdr->sh_type == SHT_PROGBITS &&
 873             !(sechdr->sh_flags & SHF_ALLOC) &&
 874             !match(sec, section_white_list)) {
 875                 warn("%s (%s): unexpected non-allocatable section.\n"
 876                      "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 877                      "Note that for example <linux/init.h> contains\n"
 878                      "section definitions for use in .S files.\n\n",
 879                      modname, sec);
 880         }
 881 }
 882
 883
 884
 885 #define ALL_INIT_DATA_SECTIONS \
 886         ".init.setup", ".init.rodata", ".meminit.rodata", \
 887         ".init.data", ".meminit.data"
 888 #define ALL_EXIT_DATA_SECTIONS \
 889         ".exit.data", ".memexit.data"
 890
 891 #define ALL_INIT_TEXT_SECTIONS \
 892         ".init.text", ".meminit.text"
 893 #define ALL_EXIT_TEXT_SECTIONS \
 894         ".exit.text", ".memexit.text"
 895
 896 #define ALL_PCI_INIT_SECTIONS   \
 897         ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
 898         ".pci_fixup_enable", ".pci_fixup_resume", \
 899         ".pci_fixup_resume_early", ".pci_fixup_suspend"
 900
 901 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
 902 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
 903
 904 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 905 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 906
 907 #define DATA_SECTIONS ".data", ".data.rel"
 908 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
 909                 ".kprobes.text", ".cpuidle.text"
 910 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
 911                 ".fixup", ".entry.text", ".exception.text", ".text.*", \
 912                 ".coldtext"
 913
 914 #define INIT_SECTIONS      ".init.*"
 915 #define MEM_INIT_SECTIONS  ".meminit.*"
 916
 917 #define EXIT_SECTIONS      ".exit.*"
 918 #define MEM_EXIT_SECTIONS  ".memexit.*"
 919
 920 #define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
 921                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
 922
 923 /* init data sections */
 924 static const char *const init_data_sections[] =
 925         { ALL_INIT_DATA_SECTIONS, NULL };
 926
 927 /* all init sections */
 928 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
 929
 930 /* All init and exit sections (code + data) */
 931 static const char *const init_exit_sections[] =
 932         {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 933
 934 /* all text sections */
 935 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
 936
 937 /* data section */
 938 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
 939
 940
 941 /* symbols in .data that may refer to init/exit sections */
 942 #define DEFAULT_SYMBOL_WHITE_LIST                                       \
 943         "*driver",                                                      \
 944         "*_template", /* scsi uses *_template a lot */                  \
 945         "*_timer",    /* arm uses ops structures named _timer a lot */  \
 946         "*_sht",      /* scsi also used *_sht to some extent */         \
 947         "*_ops",                                                        \
 948         "*_probe",                                                      \
 949         "*_probe_one",                                                  \
 950         "*_console"
 951
 952 static const char *const head_sections[] = { ".head.text*", NULL };
 953 static const char *const linker_symbols[] =
 954         { "__init_begin", "_sinittext", "_einittext", NULL };
 955 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
 956
 957 enum mismatch {
 958         TEXT_TO_ANY_INIT,
 959         DATA_TO_ANY_INIT,
 960         TEXT_TO_ANY_EXIT,
 961         DATA_TO_ANY_EXIT,
 962         XXXINIT_TO_SOME_INIT,
 963         XXXEXIT_TO_SOME_EXIT,
 964         ANY_INIT_TO_ANY_EXIT,
 965         ANY_EXIT_TO_ANY_INIT,
 966         EXPORT_TO_INIT_EXIT,
 967         EXTABLE_TO_NON_TEXT,
 968 };
 969
 970 /**
 971  * Describe how to match sections on different criterias:
 972  *
 973  * @fromsec: Array of sections to be matched.
 974  *
 975  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 976  * this array is forbidden (black-list).  Can be empty.
 977  *
 978  * @good_tosec: Relocations applied to a section in @fromsec must be
 979  * targetting sections in this array (white-list).  Can be empty.
 980  *
 981  * @mismatch: Type of mismatch.
 982  *
 983  * @symbol_white_list: Do not match a relocation to a symbol in this list
 984  * even if it is targetting a section in @bad_to_sec.
 985  *
 986  * @handler: Specific handler to call when a match is found.  If NULL,
 987  * default_mismatch_handler() will be called.
 988  *
 989  */
 990 struct sectioncheck {
 991         const char *fromsec[20];
 992         const char *bad_tosec[20];
 993         const char *good_tosec[20];
 994         enum mismatch mismatch;
 995         const char *symbol_white_list[20];
 996         void (*handler)(const char *modname, struct elf_info *elf,
 997                         const struct sectioncheck* const mismatch,
 998                         Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
 999
1000 };
1001
1002 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1003                                      const struct sectioncheck* const mismatch,
1004                                      Elf_Rela *r, Elf_Sym *sym,
1005                                      const char *fromsec);
1006
1007 static const struct sectioncheck sectioncheck[] = {
1008 /* Do not reference init/exit code/data from
1009  * normal code and data
1010  */
1011 {
1012         .fromsec = { TEXT_SECTIONS, NULL },
1013         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1014         .mismatch = TEXT_TO_ANY_INIT,
1015         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1016 },
1017 {
1018         .fromsec = { DATA_SECTIONS, NULL },
1019         .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1020         .mismatch = DATA_TO_ANY_INIT,
1021         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1022 },
1023 {
1024         .fromsec = { DATA_SECTIONS, NULL },
1025         .bad_tosec = { INIT_SECTIONS, NULL },
1026         .mismatch = DATA_TO_ANY_INIT,
1027         .symbol_white_list = {
1028                 "*_template", "*_timer", "*_sht", "*_ops",
1029                 "*_probe", "*_probe_one", "*_console", NULL
1030         },
1031 },
1032 {
1033         .fromsec = { TEXT_SECTIONS, NULL },
1034         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1035         .mismatch = TEXT_TO_ANY_EXIT,
1036         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1037 },
1038 {
1039         .fromsec = { DATA_SECTIONS, NULL },
1040         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1041         .mismatch = DATA_TO_ANY_EXIT,
1042         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1043 },
1044 /* Do not reference init code/data from meminit code/data */
1045 {
1046         .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1047         .bad_tosec = { INIT_SECTIONS, NULL },
1048         .mismatch = XXXINIT_TO_SOME_INIT,
1049         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1050 },
1051 /* Do not reference exit code/data from memexit code/data */
1052 {
1053         .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1054         .bad_tosec = { EXIT_SECTIONS, NULL },
1055         .mismatch = XXXEXIT_TO_SOME_EXIT,
1056         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1057 },
1058 /* Do not use exit code/data from init code */
1059 {
1060         .fromsec = { ALL_INIT_SECTIONS, NULL },
1061         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1062         .mismatch = ANY_INIT_TO_ANY_EXIT,
1063         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1064 },
1065 /* Do not use init code/data from exit code */
1066 {
1067         .fromsec = { ALL_EXIT_SECTIONS, NULL },
1068         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1069         .mismatch = ANY_EXIT_TO_ANY_INIT,
1070         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1071 },
1072 {
1073         .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1074         .bad_tosec = { INIT_SECTIONS, NULL },
1075         .mismatch = ANY_INIT_TO_ANY_EXIT,
1076         .symbol_white_list = { NULL },
1077 },
1078 /* Do not export init/exit functions or data */
1079 {
1080         .fromsec = { "__ksymtab*", NULL },
1081         .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1082         .mismatch = EXPORT_TO_INIT_EXIT,
1083         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1084 },
1085 {
1086         .fromsec = { "__ex_table", NULL },
1087         /* If you're adding any new black-listed sections in here, consider
1088          * adding a special 'printer' for them in scripts/check_extable.
1089          */
1090         .bad_tosec = { ".altinstr_replacement", NULL },
1091         .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1092         .mismatch = EXTABLE_TO_NON_TEXT,
1093         .handler = extable_mismatch_handler,
1094 }
1095 };
1096
1097 static const struct sectioncheck *section_mismatch(
1098                 const char *fromsec, const char *tosec)
1099 {
1100         int i;
1101         int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1102         const struct sectioncheck *check = &sectioncheck[0];
1103
1104         /*
1105          * The target section could be the SHT_NUL section when we're
1106          * handling relocations to un-resolved symbols, trying to match it
1107          * doesn't make much sense and causes build failures on parisc and
1108          * mn10300 architectures.
1109          */
1110         if (*tosec == '\0')
1111                 return NULL;
1112
1113         for (i = 0; i < elems; i++) {
1114                 if (match(fromsec, check->fromsec)) {
1115                         if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1116                                 return check;
1117                         if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1118                                 return check;
1119                 }
1120                 check++;
1121         }
1122         return NULL;
1123 }
1124
1125 /**
1126  * Whitelist to allow certain references to pass with no warning.
1127  *
1128  * Pattern 1:
1129  *   If a module parameter is declared __initdata and permissions=0
1130  *   then this is legal despite the warning generated.
1131  *   We cannot see value of permissions here, so just ignore
1132  *   this pattern.
1133  *   The pattern is identified by:
1134  *   tosec   = .init.data
1135  *   fromsec = .data*
1136  *   atsym   =__param*
1137  *
1138  * Pattern 1a:
1139  *   module_param_call() ops can refer to __init set function if permissions=0
1140  *   The pattern is identified by:
1141  *   tosec   = .init.text
1142  *   fromsec = .data*
1143  *   atsym   = __param_ops_*
1144  *
1145  * Pattern 2:
1146  *   Many drivers utilise a *driver container with references to
1147  *   add, remove, probe functions etc.
1148  *   the pattern is identified by:
1149  *   tosec   = init or exit section
1150  *   fromsec = data section
1151  *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1152  *           *probe_one, *_console, *_timer
1153  *
1154  * Pattern 3:
1155  *   Whitelist all references from .head.text to any init section
1156  *
1157  * Pattern 4:
1158  *   Some symbols belong to init section but still it is ok to reference
1159  *   these from non-init sections as these symbols don't have any memory
1160  *   allocated for them and symbol address and value are same. So even
1161  *   if init section is freed, its ok to reference those symbols.
1162  *   For ex. symbols marking the init section boundaries.
1163  *   This pattern is identified by
1164  *   refsymname = __init_begin, _sinittext, _einittext
1165  *
1166  * Pattern 5:
1167  *   GCC may optimize static inlines when fed constant arg(s) resulting
1168  *   in functions like cpumask_empty() -- generating an associated symbol
1169  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
1170  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
1171  *   meaningless section warning.  May need to add isra symbols too...
1172  *   This pattern is identified by
1173  *   tosec   = init section
1174  *   fromsec = text section
1175  *   refsymname = *.constprop.*
1176  *
1177  **/
1178 static int secref_whitelist(const struct sectioncheck *mismatch,
1179                             const char *fromsec, const char *fromsym,
1180                             const char *tosec, const char *tosym)
1181 {
1182         /* Check for pattern 1 */
1183         if (match(tosec, init_data_sections) &&
1184             match(fromsec, data_sections) &&
1185             (strncmp(fromsym, "__param", strlen("__param")) == 0))
1186                 return 0;
1187
1188         /* Check for pattern 1a */
1189         if (strcmp(tosec, ".init.text") == 0 &&
1190             match(fromsec, data_sections) &&
1191             (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1192                 return 0;
1193
1194         /* Check for pattern 2 */
1195         if (match(tosec, init_exit_sections) &&
1196             match(fromsec, data_sections) &&
1197             match(fromsym, mismatch->symbol_white_list))
1198                 return 0;
1199
1200         /* Check for pattern 3 */
1201         if (match(fromsec, head_sections) &&
1202             match(tosec, init_sections))
1203                 return 0;
1204
1205         /* Check for pattern 4 */
1206         if (match(tosym, linker_symbols))
1207                 return 0;
1208
1209         /* Check for pattern 5 */
1210         if (match(fromsec, text_sections) &&
1211             match(tosec, init_sections) &&
1212             match(fromsym, optim_symbols))
1213                 return 0;
1214
1215         return 1;
1216 }
1217
1218 /**
1219  * Find symbol based on relocation record info.
1220  * In some cases the symbol supplied is a valid symbol so
1221  * return refsym. If st_name != 0 we assume this is a valid symbol.
1222  * In other cases the symbol needs to be looked up in the symbol table
1223  * based on section and address.
1224  *  **/
1225 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1226                                 Elf_Sym *relsym)
1227 {
1228         Elf_Sym *sym;
1229         Elf_Sym *near = NULL;
1230         Elf64_Sword distance = 20;
1231         Elf64_Sword d;
1232         unsigned int relsym_secindex;
1233
1234         if (relsym->st_name != 0)
1235                 return relsym;
1236
1237         relsym_secindex = get_secindex(elf, relsym);
1238         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1239                 if (get_secindex(elf, sym) != relsym_secindex)
1240                         continue;
1241                 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1242                         continue;
1243                 if (sym->st_value == addr)
1244                         return sym;
1245                 /* Find a symbol nearby - addr are maybe negative */
1246                 d = sym->st_value - addr;
1247                 if (d < 0)
1248                         d = addr - sym->st_value;
1249                 if (d < distance) {
1250                         distance = d;
1251                         near = sym;
1252                 }
1253         }
1254         /* We need a close match */
1255         if (distance < 20)
1256                 return near;
1257         else
1258                 return NULL;
1259 }
1260
1261 static inline int is_arm_mapping_symbol(const char *str)
1262 {
1263         return str[0] == '$' && strchr("axtd", str[1])
1264                && (str[2] == '\0' || str[2] == '.');
1265 }
1266
1267 /*
1268  * If there's no name there, ignore it; likewise, ignore it if it's
1269  * one of the magic symbols emitted used by current ARM tools.
1270  *
1271  * Otherwise if find_symbols_between() returns those symbols, they'll
1272  * fail the whitelist tests and cause lots of false alarms ... fixable
1273  * only by merging __exit and __init sections into __text, bloating
1274  * the kernel (which is especially evil on embedded platforms).
1275  */
1276 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1277 {
1278         const char *name = elf->strtab + sym->st_name;
1279
1280         if (!name || !strlen(name))
1281                 return 0;
1282         return !is_arm_mapping_symbol(name);
1283 }
1284
1285 /*
1286  * Find symbols before or equal addr and after addr - in the section sec.
1287  * If we find two symbols with equal offset prefer one with a valid name.
1288  * The ELF format may have a better way to detect what type of symbol
1289  * it is, but this works for now.
1290  **/
1291 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1292                                  const char *sec)
1293 {
1294         Elf_Sym *sym;
1295         Elf_Sym *near = NULL;
1296         Elf_Addr distance = ~0;
1297
1298         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1299                 const char *symsec;
1300
1301                 if (is_shndx_special(sym->st_shndx))
1302                         continue;
1303                 symsec = sec_name(elf, get_secindex(elf, sym));
1304                 if (strcmp(symsec, sec) != 0)
1305                         continue;
1306                 if (!is_valid_name(elf, sym))
1307                         continue;
1308                 if (sym->st_value <= addr) {
1309                         if ((addr - sym->st_value) < distance) {
1310                                 distance = addr - sym->st_value;
1311                                 near = sym;
1312                         } else if ((addr - sym->st_value) == distance) {
1313                                 near = sym;
1314                         }
1315                 }
1316         }
1317         return near;
1318 }
1319
1320 /*
1321  * Convert a section name to the function/data attribute
1322  * .init.text => __init
1323  * .memexitconst => __memconst
1324  * etc.
1325  *
1326  * The memory of returned value has been allocated on a heap. The user of this
1327  * method should free it after usage.
1328 */
1329 static char *sec2annotation(const char *s)
1330 {
1331         if (match(s, init_exit_sections)) {
1332                 char *p = malloc(20);
1333                 char *r = p;
1334
1335                 *p++ = '_';
1336                 *p++ = '_';
1337                 if (*s == '.')
1338                         s++;
1339                 while (*s && *s != '.')
1340                         *p++ = *s++;
1341                 *p = '\0';
1342                 if (*s == '.')
1343                         s++;
1344                 if (strstr(s, "rodata") != NULL)
1345                         strcat(p, "const ");
1346                 else if (strstr(s, "data") != NULL)
1347                         strcat(p, "data ");
1348                 else
1349                         strcat(p, " ");
1350                 return r;
1351         } else {
1352                 return strdup("");
1353         }
1354 }
1355
1356 static int is_function(Elf_Sym *sym)
1357 {
1358         if (sym)
1359                 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1360         else
1361                 return -1;
1362 }
1363
1364 static void print_section_list(const char * const list[20])
1365 {
1366         const char *const *s = list;
1367
1368         while (*s) {
1369                 fprintf(stderr, "%s", *s);
1370                 s++;
1371                 if (*s)
1372                         fprintf(stderr, ", ");
1373         }
1374         fprintf(stderr, "\n");
1375 }
1376
1377 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1378 {
1379         switch (is_func) {
1380         case 0: *name = "variable"; *name_p = ""; break;
1381         case 1: *name = "function"; *name_p = "()"; break;
1382         default: *name = "(unknown reference)"; *name_p = ""; break;
1383         }
1384 }
1385
1386 /*
1387  * Print a warning about a section mismatch.
1388  * Try to find symbols near it so user can find it.
1389  * Check whitelist before warning - it may be a false positive.
1390  */
1391 static void report_sec_mismatch(const char *modname,
1392                                 const struct sectioncheck *mismatch,
1393                                 const char *fromsec,
1394                                 unsigned long long fromaddr,
1395                                 const char *fromsym,
1396                                 int from_is_func,
1397                                 const char *tosec, const char *tosym,
1398                                 int to_is_func)
1399 {
1400         const char *from, *from_p;
1401         const char *to, *to_p;
1402         char *prl_from;
1403         char *prl_to;
1404
1405         sec_mismatch_count++;
1406         if (!sec_mismatch_verbose)
1407                 return;
1408
1409         get_pretty_name(from_is_func, &from, &from_p);
1410         get_pretty_name(to_is_func, &to, &to_p);
1411
1412         warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1413              "to the %s %s:%s%s\n",
1414              modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1415              tosym, to_p);
1416
1417         switch (mismatch->mismatch) {
1418         case TEXT_TO_ANY_INIT:
1419                 prl_from = sec2annotation(fromsec);
1420                 prl_to = sec2annotation(tosec);
1421                 fprintf(stderr,
1422                 "The function %s%s() references\n"
1423                 "the %s %s%s%s.\n"
1424                 "This is often because %s lacks a %s\n"
1425                 "annotation or the annotation of %s is wrong.\n",
1426                 prl_from, fromsym,
1427                 to, prl_to, tosym, to_p,
1428                 fromsym, prl_to, tosym);
1429                 free(prl_from);
1430                 free(prl_to);
1431                 break;
1432         case DATA_TO_ANY_INIT: {
1433                 prl_to = sec2annotation(tosec);
1434                 fprintf(stderr,
1435                 "The variable %s references\n"
1436                 "the %s %s%s%s\n"
1437                 "If the reference is valid then annotate the\n"
1438                 "variable with __init* or __refdata (see linux/init.h) "
1439                 "or name the variable:\n",
1440                 fromsym, to, prl_to, tosym, to_p);
1441                 print_section_list(mismatch->symbol_white_list);
1442                 free(prl_to);
1443                 break;
1444         }
1445         case TEXT_TO_ANY_EXIT:
1446                 prl_to = sec2annotation(tosec);
1447                 fprintf(stderr,
1448                 "The function %s() references a %s in an exit section.\n"
1449                 "Often the %s %s%s has valid usage outside the exit section\n"
1450                 "and the fix is to remove the %sannotation of %s.\n",
1451                 fromsym, to, to, tosym, to_p, prl_to, tosym);
1452                 free(prl_to);
1453                 break;
1454         case DATA_TO_ANY_EXIT: {
1455                 prl_to = sec2annotation(tosec);
1456                 fprintf(stderr,
1457                 "The variable %s references\n"
1458                 "the %s %s%s%s\n"
1459                 "If the reference is valid then annotate the\n"
1460                 "variable with __exit* (see linux/init.h) or "
1461                 "name the variable:\n",
1462                 fromsym, to, prl_to, tosym, to_p);
1463                 print_section_list(mismatch->symbol_white_list);
1464                 free(prl_to);
1465                 break;
1466         }
1467         case XXXINIT_TO_SOME_INIT:
1468         case XXXEXIT_TO_SOME_EXIT:
1469                 prl_from = sec2annotation(fromsec);
1470                 prl_to = sec2annotation(tosec);
1471                 fprintf(stderr,
1472                 "The %s %s%s%s references\n"
1473                 "a %s %s%s%s.\n"
1474                 "If %s is only used by %s then\n"
1475                 "annotate %s with a matching annotation.\n",
1476                 from, prl_from, fromsym, from_p,
1477                 to, prl_to, tosym, to_p,
1478                 tosym, fromsym, tosym);
1479                 free(prl_from);
1480                 free(prl_to);
1481                 break;
1482         case ANY_INIT_TO_ANY_EXIT:
1483                 prl_from = sec2annotation(fromsec);
1484                 prl_to = sec2annotation(tosec);
1485                 fprintf(stderr,
1486                 "The %s %s%s%s references\n"
1487                 "a %s %s%s%s.\n"
1488                 "This is often seen when error handling "
1489                 "in the init function\n"
1490                 "uses functionality in the exit path.\n"
1491                 "The fix is often to remove the %sannotation of\n"
1492                 "%s%s so it may be used outside an exit section.\n",
1493                 from, prl_from, fromsym, from_p,
1494                 to, prl_to, tosym, to_p,
1495                 prl_to, tosym, to_p);
1496                 free(prl_from);
1497                 free(prl_to);
1498                 break;
1499         case ANY_EXIT_TO_ANY_INIT:
1500                 prl_from = sec2annotation(fromsec);
1501                 prl_to = sec2annotation(tosec);
1502                 fprintf(stderr,
1503                 "The %s %s%s%s references\n"
1504                 "a %s %s%s%s.\n"
1505                 "This is often seen when error handling "
1506                 "in the exit function\n"
1507                 "uses functionality in the init path.\n"
1508                 "The fix is often to remove the %sannotation of\n"
1509                 "%s%s so it may be used outside an init section.\n",
1510                 from, prl_from, fromsym, from_p,
1511                 to, prl_to, tosym, to_p,
1512                 prl_to, tosym, to_p);
1513                 free(prl_from);
1514                 free(prl_to);
1515                 break;
1516         case EXPORT_TO_INIT_EXIT:
1517                 prl_to = sec2annotation(tosec);
1518                 fprintf(stderr,
1519                 "The symbol %s is exported and annotated %s\n"
1520                 "Fix this by removing the %sannotation of %s "
1521                 "or drop the export.\n",
1522                 tosym, prl_to, prl_to, tosym);
1523                 free(prl_to);
1524                 break;
1525         case EXTABLE_TO_NON_TEXT:
1526                 fatal("There's a special handler for this mismatch type, "
1527                       "we should never get here.");
1528                 break;
1529         }
1530         fprintf(stderr, "\n");
1531 }
1532
1533 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1534                                      const struct sectioncheck* const mismatch,
1535                                      Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1536 {
1537         const char *tosec;
1538         Elf_Sym *to;
1539         Elf_Sym *from;
1540         const char *tosym;
1541         const char *fromsym;
1542
1543         from = find_elf_symbol2(elf, r->r_offset, fromsec);
1544         fromsym = sym_name(elf, from);
1545
1546         if (!strncmp(fromsym, "reference___initcall",
1547                      sizeof("reference___initcall")-1))
1548                 return;
1549
1550         tosec = sec_name(elf, get_secindex(elf, sym));
1551         to = find_elf_symbol(elf, r->r_addend, sym);
1552         tosym = sym_name(elf, to);
1553
1554         /* check whitelist - we may ignore it */
1555         if (secref_whitelist(mismatch,
1556                              fromsec, fromsym, tosec, tosym)) {
1557                 report_sec_mismatch(modname, mismatch,
1558                                     fromsec, r->r_offset, fromsym,
1559                                     is_function(from), tosec, tosym,
1560                                     is_function(to));
1561         }
1562 }
1563
1564 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1565 {
1566         if (section_index > elf->num_sections)
1567                 fatal("section_index is outside elf->num_sections!\n");
1568
1569         return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1570 }
1571
1572 /*
1573  * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1574  * to know the sizeof(struct exception_table_entry) for the target architecture.
1575  */
1576 static unsigned int extable_entry_size = 0;
1577 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1578 {
1579         /*
1580          * If we're currently checking the second relocation within __ex_table,
1581          * that relocation offset tells us the offsetof(struct
1582          * exception_table_entry, fixup) which is equal to sizeof(struct
1583          * exception_table_entry) divided by two.  We use that to our advantage
1584          * since there's no portable way to get that size as every architecture
1585          * seems to go with different sized types.  Not pretty but better than
1586          * hard-coding the size for every architecture..
1587          */
1588         if (!extable_entry_size)
1589                 extable_entry_size = r->r_offset * 2;
1590 }
1591
1592 static inline bool is_extable_fault_address(Elf_Rela *r)
1593 {
1594         /*
1595          * extable_entry_size is only discovered after we've handled the
1596          * _second_ relocation in __ex_table, so only abort when we're not
1597          * handling the first reloc and extable_entry_size is zero.
1598          */
1599         if (r->r_offset && extable_entry_size == 0)
1600                 fatal("extable_entry size hasn't been discovered!\n");
1601
1602         return ((r->r_offset == 0) ||
1603                 (r->r_offset % extable_entry_size == 0));
1604 }
1605
1606 #define is_second_extable_reloc(Start, Cur, Sec)                        \
1607         (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1608
1609 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1610                                     const struct sectioncheck* const mismatch,
1611                                     Elf_Rela* r, Elf_Sym* sym,
1612                                     const char* fromsec, const char* tosec)
1613 {
1614         Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1615         const char* fromsym_name = sym_name(elf, fromsym);
1616         Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1617         const char* tosym_name = sym_name(elf, tosym);
1618         const char* from_pretty_name;
1619         const char* from_pretty_name_p;
1620         const char* to_pretty_name;
1621         const char* to_pretty_name_p;
1622
1623         get_pretty_name(is_function(fromsym),
1624                         &from_pretty_name, &from_pretty_name_p);
1625         get_pretty_name(is_function(tosym),
1626                         &to_pretty_name, &to_pretty_name_p);
1627
1628         warn("%s(%s+0x%lx): Section mismatch in reference"
1629              " from the %s %s%s to the %s %s:%s%s\n",
1630              modname, fromsec, (long)r->r_offset, from_pretty_name,
1631              fromsym_name, from_pretty_name_p,
1632              to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1633
1634         if (!match(tosec, mismatch->bad_tosec) &&
1635             is_executable_section(elf, get_secindex(elf, sym)))
1636                 fprintf(stderr,
1637                         "The relocation at %s+0x%lx references\n"
1638                         "section \"%s\" which is not in the list of\n"
1639                         "authorized sections.  If you're adding a new section\n"
1640                         "and/or if this reference is valid, add \"%s\" to the\n"
1641                         "list of authorized sections to jump to on fault.\n"
1642                         "This can be achieved by adding \"%s\" to \n"
1643                         "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1644                         fromsec, (long)r->r_offset, tosec, tosec, tosec);
1645 }
1646
1647 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1648                                      const struct sectioncheck* const mismatch,
1649                                      Elf_Rela* r, Elf_Sym* sym,
1650                                      const char *fromsec)
1651 {
1652         const char* tosec = sec_name(elf, get_secindex(elf, sym));
1653
1654         sec_mismatch_count++;
1655
1656         if (sec_mismatch_verbose)
1657                 report_extable_warnings(modname, elf, mismatch, r, sym,
1658                                         fromsec, tosec);
1659
1660         if (match(tosec, mismatch->bad_tosec))
1661                 fatal("The relocation at %s+0x%lx references\n"
1662                       "section \"%s\" which is black-listed.\n"
1663                       "Something is seriously wrong and should be fixed.\n"
1664                       "You might get more information about where this is\n"
1665                       "coming from by using scripts/check_extable.sh %s\n",
1666                       fromsec, (long)r->r_offset, tosec, modname);
1667         else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1668                 if (is_extable_fault_address(r))
1669                         fatal("The relocation at %s+0x%lx references\n"
1670                               "section \"%s\" which is not executable, IOW\n"
1671                               "it is not possible for the kernel to fault\n"
1672                               "at that address.  Something is seriously wrong\n"
1673                               "and should be fixed.\n",
1674                               fromsec, (long)r->r_offset, tosec);
1675                 else
1676                         fatal("The relocation at %s+0x%lx references\n"
1677                               "section \"%s\" which is not executable, IOW\n"
1678                               "the kernel will fault if it ever tries to\n"
1679                               "jump to it.  Something is seriously wrong\n"
1680                               "and should be fixed.\n",
1681                               fromsec, (long)r->r_offset, tosec);
1682         }
1683 }
1684
1685 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1686                                    Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1687 {
1688         const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1689         const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1690
1691         if (mismatch) {
1692                 if (mismatch->handler)
1693                         mismatch->handler(modname, elf,  mismatch,
1694                                           r, sym, fromsec);
1695                 else
1696                         default_mismatch_handler(modname, elf, mismatch,
1697                                                  r, sym, fromsec);
1698         }
1699 }
1700
1701 static unsigned int *reloc_location(struct elf_info *elf,
1702                                     Elf_Shdr *sechdr, Elf_Rela *r)
1703 {
1704         Elf_Shdr *sechdrs = elf->sechdrs;
1705         int section = sechdr->sh_info;
1706
1707         return (void *)elf->hdr + sechdrs[section].sh_offset +
1708                 r->r_offset;
1709 }
1710
1711 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1712 {
1713         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1714         unsigned int *location = reloc_location(elf, sechdr, r);
1715
1716         switch (r_typ) {
1717         case R_386_32:
1718                 r->r_addend = TO_NATIVE(*location);
1719                 break;
1720         case R_386_PC32:
1721                 r->r_addend = TO_NATIVE(*location) + 4;
1722                 /* For CONFIG_RELOCATABLE=y */
1723                 if (elf->hdr->e_type == ET_EXEC)
1724                         r->r_addend += r->r_offset;
1725                 break;
1726         }
1727         return 0;
1728 }
1729
1730 #ifndef R_ARM_CALL
1731 #define R_ARM_CALL      28
1732 #endif
1733 #ifndef R_ARM_JUMP24
1734 #define R_ARM_JUMP24    29
1735 #endif
1736
1737 #ifndef R_ARM_THM_CALL
1738 #define R_ARM_THM_CALL          10
1739 #endif
1740 #ifndef R_ARM_THM_JUMP24
1741 #define R_ARM_THM_JUMP24        30
1742 #endif
1743 #ifndef R_ARM_THM_JUMP19
1744 #define R_ARM_THM_JUMP19        51
1745 #endif
1746
1747 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1748 {
1749         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1750
1751         switch (r_typ) {
1752         case R_ARM_ABS32:
1753                 /* From ARM ABI: (S + A) | T */
1754                 r->r_addend = (int)(long)
1755                               (elf->symtab_start + ELF_R_SYM(r->r_info));
1756                 break;
1757         case R_ARM_PC24:
1758         case R_ARM_CALL:
1759         case R_ARM_JUMP24:
1760         case R_ARM_THM_CALL:
1761         case R_ARM_THM_JUMP24:
1762         case R_ARM_THM_JUMP19:
1763                 /* From ARM ABI: ((S + A) | T) - P */
1764                 r->r_addend = (int)(long)(elf->hdr +
1765                               sechdr->sh_offset +
1766                               (r->r_offset - sechdr->sh_addr));
1767                 break;
1768         default:
1769                 return 1;
1770         }
1771         return 0;
1772 }
1773
1774 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1775 {
1776         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1777         unsigned int *location = reloc_location(elf, sechdr, r);
1778         unsigned int inst;
1779
1780         if (r_typ == R_MIPS_HI16)
1781                 return 1;       /* skip this */
1782         inst = TO_NATIVE(*location);
1783         switch (r_typ) {
1784         case R_MIPS_LO16:
1785                 r->r_addend = inst & 0xffff;
1786                 break;
1787         case R_MIPS_26:
1788                 r->r_addend = (inst & 0x03ffffff) << 2;
1789                 break;
1790         case R_MIPS_32:
1791                 r->r_addend = inst;
1792                 break;
1793         }
1794         return 0;
1795 }
1796
1797 static void section_rela(const char *modname, struct elf_info *elf,
1798                          Elf_Shdr *sechdr)
1799 {
1800         Elf_Sym  *sym;
1801         Elf_Rela *rela;
1802         Elf_Rela r;
1803         unsigned int r_sym;
1804         const char *fromsec;
1805
1806         Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1807         Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1808
1809         fromsec = sech_name(elf, sechdr);
1810         fromsec += strlen(".rela");
1811         /* if from section (name) is know good then skip it */
1812         if (match(fromsec, section_white_list))
1813                 return;
1814
1815         for (rela = start; rela < stop; rela++) {
1816                 r.r_offset = TO_NATIVE(rela->r_offset);
1817 #if KERNEL_ELFCLASS == ELFCLASS64
1818                 if (elf->hdr->e_machine == EM_MIPS) {
1819                         unsigned int r_typ;
1820                         r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1821                         r_sym = TO_NATIVE(r_sym);
1822                         r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1823                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1824                 } else {
1825                         r.r_info = TO_NATIVE(rela->r_info);
1826                         r_sym = ELF_R_SYM(r.r_info);
1827                 }
1828 #else
1829                 r.r_info = TO_NATIVE(rela->r_info);
1830                 r_sym = ELF_R_SYM(r.r_info);
1831 #endif
1832                 r.r_addend = TO_NATIVE(rela->r_addend);
1833                 sym = elf->symtab_start + r_sym;
1834                 /* Skip special sections */
1835                 if (is_shndx_special(sym->st_shndx))
1836                         continue;
1837                 if (is_second_extable_reloc(start, rela, fromsec))
1838                         find_extable_entry_size(fromsec, &r);
1839                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1840         }
1841 }
1842
1843 static void section_rel(const char *modname, struct elf_info *elf,
1844                         Elf_Shdr *sechdr)
1845 {
1846         Elf_Sym *sym;
1847         Elf_Rel *rel;
1848         Elf_Rela r;
1849         unsigned int r_sym;
1850         const char *fromsec;
1851
1852         Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1853         Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1854
1855         fromsec = sech_name(elf, sechdr);
1856         fromsec += strlen(".rel");
1857         /* if from section (name) is know good then skip it */
1858         if (match(fromsec, section_white_list))
1859                 return;
1860
1861         for (rel = start; rel < stop; rel++) {
1862                 r.r_offset = TO_NATIVE(rel->r_offset);
1863 #if KERNEL_ELFCLASS == ELFCLASS64
1864                 if (elf->hdr->e_machine == EM_MIPS) {
1865                         unsigned int r_typ;
1866                         r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1867                         r_sym = TO_NATIVE(r_sym);
1868                         r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1869                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1870                 } else {
1871                         r.r_info = TO_NATIVE(rel->r_info);
1872                         r_sym = ELF_R_SYM(r.r_info);
1873                 }
1874 #else
1875                 r.r_info = TO_NATIVE(rel->r_info);
1876                 r_sym = ELF_R_SYM(r.r_info);
1877 #endif
1878                 r.r_addend = 0;
1879                 switch (elf->hdr->e_machine) {
1880                 case EM_386:
1881                         if (addend_386_rel(elf, sechdr, &r))
1882                                 continue;
1883                         break;
1884                 case EM_ARM:
1885                         if (addend_arm_rel(elf, sechdr, &r))
1886                                 continue;
1887                         break;
1888                 case EM_MIPS:
1889                         if (addend_mips_rel(elf, sechdr, &r))
1890                                 continue;
1891                         break;
1892                 }
1893                 sym = elf->symtab_start + r_sym;
1894                 /* Skip special sections */
1895                 if (is_shndx_special(sym->st_shndx))
1896                         continue;
1897                 if (is_second_extable_reloc(start, rel, fromsec))
1898                         find_extable_entry_size(fromsec, &r);
1899                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1900         }
1901 }
1902
1903 /**
1904  * A module includes a number of sections that are discarded
1905  * either when loaded or when used as built-in.
1906  * For loaded modules all functions marked __init and all data
1907  * marked __initdata will be discarded when the module has been initialized.
1908  * Likewise for modules used built-in the sections marked __exit
1909  * are discarded because __exit marked function are supposed to be called
1910  * only when a module is unloaded which never happens for built-in modules.
1911  * The check_sec_ref() function traverses all relocation records
1912  * to find all references to a section that reference a section that will
1913  * be discarded and warns about it.
1914  **/
1915 static void check_sec_ref(struct module *mod, const char *modname,
1916                           struct elf_info *elf)
1917 {
1918         int i;
1919         Elf_Shdr *sechdrs = elf->sechdrs;
1920
1921         /* Walk through all sections */
1922         for (i = 0; i < elf->num_sections; i++) {
1923                 check_section(modname, elf, &elf->sechdrs[i]);
1924                 /* We want to process only relocation sections and not .init */
1925                 if (sechdrs[i].sh_type == SHT_RELA)
1926                         section_rela(modname, elf, &elf->sechdrs[i]);
1927                 else if (sechdrs[i].sh_type == SHT_REL)
1928                         section_rel(modname, elf, &elf->sechdrs[i]);
1929         }
1930 }
1931
1932 static char *remove_dot(char *s)
1933 {
1934         size_t n = strcspn(s, ".");
1935
1936         if (n && s[n]) {
1937                 size_t m = strspn(s + n + 1, "0123456789");
1938                 if (m && (s[n + m] == '.' || s[n + m] == 0))
1939                         s[n] = 0;
1940         }
1941         return s;
1942 }
1943
1944 static void read_symbols(char *modname)
1945 {
1946         const char *symname;
1947         char *version;
1948         char *license;
1949         struct module *mod;
1950         struct elf_info info = { };
1951         Elf_Sym *sym;
1952
1953         if (!parse_elf(&info, modname))
1954                 return;
1955
1956         mod = new_module(modname);
1957
1958         /* When there's no vmlinux, don't print warnings about
1959          * unresolved symbols (since there'll be too many ;) */
1960         if (is_vmlinux(modname)) {
1961                 have_vmlinux = 1;
1962                 mod->skip = 1;
1963         }
1964
1965         license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1966         if (info.modinfo && !license && !is_vmlinux(modname))
1967                 warn("modpost: missing MODULE_LICENSE() in %s\n"
1968                      "see include/linux/module.h for "
1969                      "more information\n", modname);
1970         while (license) {
1971                 if (license_is_gpl_compatible(license))
1972                         mod->gpl_compatible = 1;
1973                 else {
1974                         mod->gpl_compatible = 0;
1975                         break;
1976                 }
1977                 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1978                                            "license", license);
1979         }
1980
1981         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1982                 symname = remove_dot(info.strtab + sym->st_name);
1983
1984                 handle_modversions(mod, &info, sym, symname);
1985                 handle_moddevtable(mod, &info, sym, symname);
1986         }
1987         if (!is_vmlinux(modname) ||
1988              (is_vmlinux(modname) && vmlinux_section_warnings))
1989                 check_sec_ref(mod, modname, &info);
1990
1991         version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1992         if (version)
1993                 maybe_frob_rcs_version(modname, version, info.modinfo,
1994                                        version - (char *)info.hdr);
1995         if (version || (all_versions && !is_vmlinux(modname)))
1996                 get_src_version(modname, mod->srcversion,
1997                                 sizeof(mod->srcversion)-1);
1998
1999         parse_elf_finish(&info);
2000
2001         /* Our trick to get versioning for module struct etc. - it's
2002          * never passed as an argument to an exported function, so
2003          * the automatic versioning doesn't pick it up, but it's really
2004          * important anyhow */
2005         if (modversions)
2006                 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2007 }
2008
2009 static void read_symbols_from_files(const char *filename)
2010 {
2011         FILE *in = stdin;
2012         char fname[PATH_MAX];
2013
2014         if (strcmp(filename, "-") != 0) {
2015                 in = fopen(filename, "r");
2016                 if (!in)
2017                         fatal("Can't open filenames file %s: %m", filename);
2018         }
2019
2020         while (fgets(fname, PATH_MAX, in) != NULL) {
2021                 if (strends(fname, "\n"))
2022                         fname[strlen(fname)-1] = '\0';
2023                 read_symbols(fname);
2024         }
2025
2026         if (in != stdin)
2027                 fclose(in);
2028 }
2029
2030 #define SZ 500
2031
2032 /* We first write the generated file into memory using the
2033  * following helper, then compare to the file on disk and
2034  * only update the later if anything changed */
2035
2036 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2037                                                       const char *fmt, ...)
2038 {
2039         char tmp[SZ];
2040         int len;
2041         va_list ap;
2042
2043         va_start(ap, fmt);
2044         len = vsnprintf(tmp, SZ, fmt, ap);
2045         buf_write(buf, tmp, len);
2046         va_end(ap);
2047 }
2048
2049 void buf_write(struct buffer *buf, const char *s, int len)
2050 {
2051         if (buf->size - buf->pos < len) {
2052                 buf->size += len + SZ;
2053                 buf->p = realloc(buf->p, buf->size);
2054         }
2055         strncpy(buf->p + buf->pos, s, len);
2056         buf->pos += len;
2057 }
2058
2059 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2060 {
2061         const char *e = is_vmlinux(m) ?"":".ko";
2062
2063         switch (exp) {
2064         case export_gpl:
2065                 fatal("modpost: GPL-incompatible module %s%s "
2066                       "uses GPL-only symbol '%s'\n", m, e, s);
2067                 break;
2068         case export_unused_gpl:
2069                 fatal("modpost: GPL-incompatible module %s%s "
2070                       "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2071                 break;
2072         case export_gpl_future:
2073                 warn("modpost: GPL-incompatible module %s%s "
2074                       "uses future GPL-only symbol '%s'\n", m, e, s);
2075                 break;
2076         case export_plain:
2077         case export_unused:
2078         case export_unknown:
2079                 /* ignore */
2080                 break;
2081         }
2082 }
2083
2084 static void check_for_unused(enum export exp, const char *m, const char *s)
2085 {
2086         const char *e = is_vmlinux(m) ?"":".ko";
2087
2088         switch (exp) {
2089         case export_unused:
2090         case export_unused_gpl:
2091                 warn("modpost: module %s%s "
2092                       "uses symbol '%s' marked UNUSED\n", m, e, s);
2093                 break;
2094         default:
2095                 /* ignore */
2096                 break;
2097         }
2098 }
2099
2100 static void check_exports(struct module *mod)
2101 {
2102         struct symbol *s, *exp;
2103
2104         for (s = mod->unres; s; s = s->next) {
2105                 const char *basename;
2106                 exp = find_symbol(s->name);
2107                 if (!exp || exp->module == mod)
2108                         continue;
2109                 basename = strrchr(mod->name, '/');
2110                 if (basename)
2111                         basename++;
2112                 else
2113                         basename = mod->name;
2114                 if (!mod->gpl_compatible)
2115                         check_for_gpl_usage(exp->export, basename, exp->name);
2116                 check_for_unused(exp->export, basename, exp->name);
2117         }
2118 }
2119
2120 static int check_modname_len(struct module *mod)
2121 {
2122         const char *mod_name;
2123
2124         mod_name = strrchr(mod->name, '/');
2125         if (mod_name == NULL)
2126                 mod_name = mod->name;
2127         else
2128                 mod_name++;
2129         if (strlen(mod_name) >= MODULE_NAME_LEN) {
2130                 merror("module name is too long [%s.ko]\n", mod->name);
2131                 return 1;
2132         }
2133
2134         return 0;
2135 }
2136
2137 /**
2138  * Header for the generated file
2139  **/
2140 static void add_header(struct buffer *b, struct module *mod)
2141 {
2142         buf_printf(b, "#include <linux/module.h>\n");
2143         buf_printf(b, "#include <linux/vermagic.h>\n");
2144         buf_printf(b, "#include <linux/compiler.h>\n");
2145         buf_printf(b, "\n");
2146         buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2147         buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2148         buf_printf(b, "\n");
2149         buf_printf(b, "__visible struct module __this_module\n");
2150         buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2151         buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2152         if (mod->has_init)
2153                 buf_printf(b, "\t.init = init_module,\n");
2154         if (mod->has_cleanup)
2155                 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2156                               "\t.exit = cleanup_module,\n"
2157                               "#endif\n");
2158         buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2159         buf_printf(b, "};\n");
2160 }
2161
2162 static void add_intree_flag(struct buffer *b, int is_intree)
2163 {
2164         if (is_intree)
2165                 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2166 }
2167
2168 static void add_staging_flag(struct buffer *b, const char *name)
2169 {
2170         static const char *staging_dir = "drivers/staging";
2171
2172         if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2173                 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2174 }
2175
2176 /**
2177  * Record CRCs for unresolved symbols
2178  **/
2179 static int add_versions(struct buffer *b, struct module *mod)
2180 {
2181         struct symbol *s, *exp;
2182         int err = 0;
2183
2184         for (s = mod->unres; s; s = s->next) {
2185                 exp = find_symbol(s->name);
2186                 if (!exp || exp->module == mod) {
2187                         if (have_vmlinux && !s->weak) {
2188                                 if (warn_unresolved) {
2189                                         warn("\"%s\" [%s.ko] undefined!\n",
2190                                              s->name, mod->name);
2191                                 } else {
2192                                         merror("\"%s\" [%s.ko] undefined!\n",
2193                                                s->name, mod->name);
2194                                         err = 1;
2195                                 }
2196                         }
2197                         continue;
2198                 }
2199                 s->module = exp->module;
2200                 s->crc_valid = exp->crc_valid;
2201                 s->crc = exp->crc;
2202         }
2203
2204         if (!modversions)
2205                 return err;
2206
2207         buf_printf(b, "\n");
2208         buf_printf(b, "static const struct modversion_info ____versions[]\n");
2209         buf_printf(b, "__used\n");
2210         buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2211
2212         for (s = mod->unres; s; s = s->next) {
2213                 if (!s->module)
2214                         continue;
2215                 if (!s->crc_valid) {
2216                         warn("\"%s\" [%s.ko] has no CRC!\n",
2217                                 s->name, mod->name);
2218                         continue;
2219                 }
2220                 if (strlen(s->name) >= MODULE_NAME_LEN) {
2221                         merror("too long symbol \"%s\" [%s.ko]\n",
2222                                s->name, mod->name);
2223                         err = 1;
2224                         break;
2225                 }
2226                 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2227                            s->crc, s->name);
2228         }
2229
2230         buf_printf(b, "};\n");
2231
2232         return err;
2233 }
2234
2235 static void add_depends(struct buffer *b, struct module *mod,
2236                         struct module *modules)
2237 {
2238         struct symbol *s;
2239         struct module *m;
2240         int first = 1;
2241
2242         for (m = modules; m; m = m->next)
2243                 m->seen = is_vmlinux(m->name);
2244
2245         buf_printf(b, "\n");
2246         buf_printf(b, "static const char __module_depends[]\n");
2247         buf_printf(b, "__used\n");
2248         buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2249         buf_printf(b, "\"depends=");
2250         for (s = mod->unres; s; s = s->next) {
2251                 const char *p;
2252                 if (!s->module)
2253                         continue;
2254
2255                 if (s->module->seen)
2256                         continue;
2257
2258                 s->module->seen = 1;
2259                 p = strrchr(s->module->name, '/');
2260                 if (p)
2261                         p++;
2262                 else
2263                         p = s->module->name;
2264                 buf_printf(b, "%s%s", first ? "" : ",", p);
2265                 first = 0;
2266         }
2267         buf_printf(b, "\";\n");
2268 }
2269
2270 static void add_srcversion(struct buffer *b, struct module *mod)
2271 {
2272         if (mod->srcversion[0]) {
2273                 buf_printf(b, "\n");
2274                 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2275                            mod->srcversion);
2276         }
2277 }
2278
2279 static void write_if_changed(struct buffer *b, const char *fname)
2280 {
2281         char *tmp;
2282         FILE *file;
2283         struct stat st;
2284
2285         file = fopen(fname, "r");
2286         if (!file)
2287                 goto write;
2288
2289         if (fstat(fileno(file), &st) < 0)
2290                 goto close_write;
2291
2292         if (st.st_size != b->pos)
2293                 goto close_write;
2294
2295         tmp = NOFAIL(malloc(b->pos));
2296         if (fread(tmp, 1, b->pos, file) != b->pos)
2297                 goto free_write;
2298
2299         if (memcmp(tmp, b->p, b->pos) != 0)
2300                 goto free_write;
2301
2302         free(tmp);
2303         fclose(file);
2304         return;
2305
2306  free_write:
2307         free(tmp);
2308  close_write:
2309         fclose(file);
2310  write:
2311         file = fopen(fname, "w");
2312         if (!file) {
2313                 perror(fname);
2314                 exit(1);
2315         }
2316         if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2317                 perror(fname);
2318                 exit(1);
2319         }
2320         fclose(file);
2321 }
2322
2323 /* parse Module.symvers file. line format:
2324  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2325  **/
2326 static void read_dump(const char *fname, unsigned int kernel)
2327 {
2328         unsigned long size, pos = 0;
2329         void *file = grab_file(fname, &size);
2330         char *line;
2331
2332         if (!file)
2333                 /* No symbol versions, silently ignore */
2334                 return;
2335
2336         while ((line = get_next_line(&pos, file, size))) {
2337                 char *symname, *modname, *d, *export, *end;
2338                 unsigned int crc;
2339                 struct module *mod;
2340                 struct symbol *s;
2341
2342                 if (!(symname = strchr(line, '\t')))
2343                         goto fail;
2344                 *symname++ = '\0';
2345                 if (!(modname = strchr(symname, '\t')))
2346                         goto fail;
2347                 *modname++ = '\0';
2348                 if ((export = strchr(modname, '\t')) != NULL)
2349                         *export++ = '\0';
2350                 if (export && ((end = strchr(export, '\t')) != NULL))
2351                         *end = '\0';
2352                 crc = strtoul(line, &d, 16);
2353                 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2354                         goto fail;
2355                 mod = find_module(modname);
2356                 if (!mod) {
2357                         if (is_vmlinux(modname))
2358                                 have_vmlinux = 1;
2359                         mod = new_module(modname);
2360                         mod->skip = 1;
2361                 }
2362                 s = sym_add_exported(symname, mod, export_no(export));
2363                 s->kernel    = kernel;
2364                 s->preloaded = 1;
2365                 sym_update_crc(symname, mod, crc, export_no(export));
2366         }
2367         release_file(file, size);
2368         return;
2369 fail:
2370         release_file(file, size);
2371         fatal("parse error in symbol dump file\n");
2372 }
2373
2374 /* For normal builds always dump all symbols.
2375  * For external modules only dump symbols
2376  * that are not read from kernel Module.symvers.
2377  **/
2378 static int dump_sym(struct symbol *sym)
2379 {
2380         if (!external_module)
2381                 return 1;
2382         if (sym->vmlinux || sym->kernel)
2383                 return 0;
2384         return 1;
2385 }
2386
2387 static void write_dump(const char *fname)
2388 {
2389         struct buffer buf = { };
2390         struct symbol *symbol;
2391         int n;
2392
2393         for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2394                 symbol = symbolhash[n];
2395                 while (symbol) {
2396                         if (dump_sym(symbol))
2397                                 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2398                                         symbol->crc, symbol->name,
2399                                         symbol->module->name,
2400                                         export_str(symbol->export));
2401                         symbol = symbol->next;
2402                 }
2403         }
2404         write_if_changed(&buf, fname);
2405         free(buf.p);
2406 }
2407
2408 struct ext_sym_list {
2409         struct ext_sym_list *next;
2410         const char *file;
2411 };
2412
2413 int main(int argc, char **argv)
2414 {
2415         struct module *mod;
2416         struct buffer buf = { };
2417         char *kernel_read = NULL, *module_read = NULL;
2418         char *dump_write = NULL, *files_source = NULL;
2419         int opt;
2420         int err;
2421         struct ext_sym_list *extsym_iter;
2422         struct ext_sym_list *extsym_start = NULL;
2423
2424         while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2425                 switch (opt) {
2426                 case 'i':
2427                         kernel_read = optarg;
2428                         break;
2429                 case 'I':
2430                         module_read = optarg;
2431                         external_module = 1;
2432                         break;
2433                 case 'e':
2434                         external_module = 1;
2435                         extsym_iter =
2436                            NOFAIL(malloc(sizeof(*extsym_iter)));
2437                         extsym_iter->next = extsym_start;
2438                         extsym_iter->file = optarg;
2439                         extsym_start = extsym_iter;
2440                         break;
2441                 case 'm':
2442                         modversions = 1;
2443                         break;
2444                 case 'n':
2445                         ignore_missing_files = 1;
2446                         break;
2447                 case 'o':
2448                         dump_write = optarg;
2449                         break;
2450                 case 'a':
2451                         all_versions = 1;
2452                         break;
2453                 case 's':
2454                         vmlinux_section_warnings = 0;
2455                         break;
2456                 case 'S':
2457                         sec_mismatch_verbose = 0;
2458                         break;
2459                 case 'T':
2460                         files_source = optarg;
2461                         break;
2462                 case 'w':
2463                         warn_unresolved = 1;
2464                         break;
2465                 case 'E':
2466                         sec_mismatch_fatal = 1;
2467                         break;
2468                 default:
2469                         exit(1);
2470                 }
2471         }
2472
2473         if (kernel_read)
2474                 read_dump(kernel_read, 1);
2475         if (module_read)
2476                 read_dump(module_read, 0);
2477         while (extsym_start) {
2478                 read_dump(extsym_start->file, 0);
2479                 extsym_iter = extsym_start->next;
2480                 free(extsym_start);
2481                 extsym_start = extsym_iter;
2482         }
2483
2484         while (optind < argc)
2485                 read_symbols(argv[optind++]);
2486
2487         if (files_source)
2488                 read_symbols_from_files(files_source);
2489
2490         for (mod = modules; mod; mod = mod->next) {
2491                 if (mod->skip)
2492                         continue;
2493                 check_exports(mod);
2494         }
2495
2496         err = 0;
2497
2498         for (mod = modules; mod; mod = mod->next) {
2499                 char fname[PATH_MAX];
2500
2501                 if (mod->skip)
2502                         continue;
2503
2504                 buf.pos = 0;
2505
2506                 err |= check_modname_len(mod);
2507                 add_header(&buf, mod);
2508                 add_intree_flag(&buf, !external_module);
2509                 add_staging_flag(&buf, mod->name);
2510                 err |= add_versions(&buf, mod);
2511                 add_depends(&buf, mod, modules);
2512                 add_moddevtable(&buf, mod);
2513                 add_srcversion(&buf, mod);
2514
2515                 sprintf(fname, "%s.mod.c", mod->name);
2516                 write_if_changed(&buf, fname);
2517         }
2518         if (dump_write)
2519                 write_dump(dump_write);
2520         if (sec_mismatch_count) {
2521                 if (!sec_mismatch_verbose) {
2522                         warn("modpost: Found %d section mismatch(es).\n"
2523                              "To see full details build your kernel with:\n"
2524                              "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2525                              sec_mismatch_count);
2526                 }
2527                 if (sec_mismatch_fatal) {
2528                         fatal("modpost: Section mismatches detected.\n"
2529                               "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2530                 }
2531         }
2532         free(buf.p);
2533
2534         return err;
2535 }