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",    /* record-gcc-switches */
 844         ".mdebug*",        /* alpha, score, mips etc. */
 845         ".pdr",            /* alpha, score, mips etc. */
 846         ".stab*",
 847         ".note*",
 848         ".got*",
 849         ".toc*",
 850         ".xt.prop",                              /* xtensa */
 851         ".xt.lit",         /* xtensa */
 852         ".arcextmap*",                  /* arc */
 853         ".gnu.linkonce.arcext*",        /* arc : modules */
 854         ".cmem*",                       /* EZchip */
 855         ".fmt_slot*",                   /* EZchip */
 856         ".gnu.lto*",
 857         ".discard.*",
 858         NULL
 859 };
 860
 861 /*
 862  * This is used to find sections missing the SHF_ALLOC flag.
 863  * The cause of this is often a section specified in assembler
 864  * without "ax" / "aw".
 865  */
 866 static void check_section(const char *modname, struct elf_info *elf,
 867                           Elf_Shdr *sechdr)
 868 {
 869         const char *sec = sech_name(elf, sechdr);
 870
 871         if (sechdr->sh_type == SHT_PROGBITS &&
 872             !(sechdr->sh_flags & SHF_ALLOC) &&
 873             !match(sec, section_white_list)) {
 874                 warn("%s (%s): unexpected non-allocatable section.\n"
 875                      "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 876                      "Note that for example <linux/init.h> contains\n"
 877                      "section definitions for use in .S files.\n\n",
 878                      modname, sec);
 879         }
 880 }
 881
 882
 883
 884 #define ALL_INIT_DATA_SECTIONS \
 885         ".init.setup", ".init.rodata", ".meminit.rodata", \
 886         ".init.data", ".meminit.data"
 887 #define ALL_EXIT_DATA_SECTIONS \
 888         ".exit.data", ".memexit.data"
 889
 890 #define ALL_INIT_TEXT_SECTIONS \
 891         ".init.text", ".meminit.text"
 892 #define ALL_EXIT_TEXT_SECTIONS \
 893         ".exit.text", ".memexit.text"
 894
 895 #define ALL_PCI_INIT_SECTIONS   \
 896         ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
 897         ".pci_fixup_enable", ".pci_fixup_resume", \
 898         ".pci_fixup_resume_early", ".pci_fixup_suspend"
 899
 900 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
 901 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
 902
 903 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 904 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 905
 906 #define DATA_SECTIONS ".data", ".data.rel"
 907 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
 908                 ".kprobes.text", ".cpuidle.text"
 909 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
 910                 ".fixup", ".entry.text", ".exception.text", ".text.*", \
 911                 ".coldtext"
 912
 913 #define INIT_SECTIONS      ".init.*"
 914 #define MEM_INIT_SECTIONS  ".meminit.*"
 915
 916 #define EXIT_SECTIONS      ".exit.*"
 917 #define MEM_EXIT_SECTIONS  ".memexit.*"
 918
 919 #define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
 920                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
 921
 922 /* init data sections */
 923 static const char *const init_data_sections[] =
 924         { ALL_INIT_DATA_SECTIONS, NULL };
 925
 926 /* all init sections */
 927 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
 928
 929 /* All init and exit sections (code + data) */
 930 static const char *const init_exit_sections[] =
 931         {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 932
 933 /* all text sections */
 934 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
 935
 936 /* data section */
 937 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
 938
 939
 940 /* symbols in .data that may refer to init/exit sections */
 941 #define DEFAULT_SYMBOL_WHITE_LIST                                       \
 942         "*driver",                                                      \
 943         "*_template", /* scsi uses *_template a lot */                  \
 944         "*_timer",    /* arm uses ops structures named _timer a lot */  \
 945         "*_sht",      /* scsi also used *_sht to some extent */         \
 946         "*_ops",                                                        \
 947         "*_probe",                                                      \
 948         "*_probe_one",                                                  \
 949         "*_console"
 950
 951 static const char *const head_sections[] = { ".head.text*", NULL };
 952 static const char *const linker_symbols[] =
 953         { "__init_begin", "_sinittext", "_einittext", NULL };
 954 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
 955
 956 enum mismatch {
 957         TEXT_TO_ANY_INIT,
 958         DATA_TO_ANY_INIT,
 959         TEXT_TO_ANY_EXIT,
 960         DATA_TO_ANY_EXIT,
 961         XXXINIT_TO_SOME_INIT,
 962         XXXEXIT_TO_SOME_EXIT,
 963         ANY_INIT_TO_ANY_EXIT,
 964         ANY_EXIT_TO_ANY_INIT,
 965         EXPORT_TO_INIT_EXIT,
 966         EXTABLE_TO_NON_TEXT,
 967 };
 968
 969 /**
 970  * Describe how to match sections on different criterias:
 971  *
 972  * @fromsec: Array of sections to be matched.
 973  *
 974  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 975  * this array is forbidden (black-list).  Can be empty.
 976  *
 977  * @good_tosec: Relocations applied to a section in @fromsec must be
 978  * targetting sections in this array (white-list).  Can be empty.
 979  *
 980  * @mismatch: Type of mismatch.
 981  *
 982  * @symbol_white_list: Do not match a relocation to a symbol in this list
 983  * even if it is targetting a section in @bad_to_sec.
 984  *
 985  * @handler: Specific handler to call when a match is found.  If NULL,
 986  * default_mismatch_handler() will be called.
 987  *
 988  */
 989 struct sectioncheck {
 990         const char *fromsec[20];
 991         const char *bad_tosec[20];
 992         const char *good_tosec[20];
 993         enum mismatch mismatch;
 994         const char *symbol_white_list[20];
 995         void (*handler)(const char *modname, struct elf_info *elf,
 996                         const struct sectioncheck* const mismatch,
 997                         Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
 998
 999 };
1000
1001 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1002                                      const struct sectioncheck* const mismatch,
1003                                      Elf_Rela *r, Elf_Sym *sym,
1004                                      const char *fromsec);
1005
1006 static const struct sectioncheck sectioncheck[] = {
1007 /* Do not reference init/exit code/data from
1008  * normal code and data
1009  */
1010 {
1011         .fromsec = { TEXT_SECTIONS, NULL },
1012         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1013         .mismatch = TEXT_TO_ANY_INIT,
1014         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1015 },
1016 {
1017         .fromsec = { DATA_SECTIONS, NULL },
1018         .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1019         .mismatch = DATA_TO_ANY_INIT,
1020         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1021 },
1022 {
1023         .fromsec = { DATA_SECTIONS, NULL },
1024         .bad_tosec = { INIT_SECTIONS, NULL },
1025         .mismatch = DATA_TO_ANY_INIT,
1026         .symbol_white_list = {
1027                 "*_template", "*_timer", "*_sht", "*_ops",
1028                 "*_probe", "*_probe_one", "*_console", NULL
1029         },
1030 },
1031 {
1032         .fromsec = { TEXT_SECTIONS, NULL },
1033         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1034         .mismatch = TEXT_TO_ANY_EXIT,
1035         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1036 },
1037 {
1038         .fromsec = { DATA_SECTIONS, NULL },
1039         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1040         .mismatch = DATA_TO_ANY_EXIT,
1041         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1042 },
1043 /* Do not reference init code/data from meminit code/data */
1044 {
1045         .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1046         .bad_tosec = { INIT_SECTIONS, NULL },
1047         .mismatch = XXXINIT_TO_SOME_INIT,
1048         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1049 },
1050 /* Do not reference exit code/data from memexit code/data */
1051 {
1052         .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1053         .bad_tosec = { EXIT_SECTIONS, NULL },
1054         .mismatch = XXXEXIT_TO_SOME_EXIT,
1055         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1056 },
1057 /* Do not use exit code/data from init code */
1058 {
1059         .fromsec = { ALL_INIT_SECTIONS, NULL },
1060         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1061         .mismatch = ANY_INIT_TO_ANY_EXIT,
1062         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1063 },
1064 /* Do not use init code/data from exit code */
1065 {
1066         .fromsec = { ALL_EXIT_SECTIONS, NULL },
1067         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1068         .mismatch = ANY_EXIT_TO_ANY_INIT,
1069         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1070 },
1071 {
1072         .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1073         .bad_tosec = { INIT_SECTIONS, NULL },
1074         .mismatch = ANY_INIT_TO_ANY_EXIT,
1075         .symbol_white_list = { NULL },
1076 },
1077 /* Do not export init/exit functions or data */
1078 {
1079         .fromsec = { "__ksymtab*", NULL },
1080         .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1081         .mismatch = EXPORT_TO_INIT_EXIT,
1082         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1083 },
1084 {
1085         .fromsec = { "__ex_table", NULL },
1086         /* If you're adding any new black-listed sections in here, consider
1087          * adding a special 'printer' for them in scripts/check_extable.
1088          */
1089         .bad_tosec = { ".altinstr_replacement", NULL },
1090         .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1091         .mismatch = EXTABLE_TO_NON_TEXT,
1092         .handler = extable_mismatch_handler,
1093 }
1094 };
1095
1096 static const struct sectioncheck *section_mismatch(
1097                 const char *fromsec, const char *tosec)
1098 {
1099         int i;
1100         int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1101         const struct sectioncheck *check = &sectioncheck[0];
1102
1103         /*
1104          * The target section could be the SHT_NUL section when we're
1105          * handling relocations to un-resolved symbols, trying to match it
1106          * doesn't make much sense and causes build failures on parisc
1107          * architectures.
1108          */
1109         if (*tosec == '\0')
1110                 return NULL;
1111
1112         for (i = 0; i < elems; i++) {
1113                 if (match(fromsec, check->fromsec)) {
1114                         if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1115                                 return check;
1116                         if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1117                                 return check;
1118                 }
1119                 check++;
1120         }
1121         return NULL;
1122 }
1123
1124 /**
1125  * Whitelist to allow certain references to pass with no warning.
1126  *
1127  * Pattern 1:
1128  *   If a module parameter is declared __initdata and permissions=0
1129  *   then this is legal despite the warning generated.
1130  *   We cannot see value of permissions here, so just ignore
1131  *   this pattern.
1132  *   The pattern is identified by:
1133  *   tosec   = .init.data
1134  *   fromsec = .data*
1135  *   atsym   =__param*
1136  *
1137  * Pattern 1a:
1138  *   module_param_call() ops can refer to __init set function if permissions=0
1139  *   The pattern is identified by:
1140  *   tosec   = .init.text
1141  *   fromsec = .data*
1142  *   atsym   = __param_ops_*
1143  *
1144  * Pattern 2:
1145  *   Many drivers utilise a *driver container with references to
1146  *   add, remove, probe functions etc.
1147  *   the pattern is identified by:
1148  *   tosec   = init or exit section
1149  *   fromsec = data section
1150  *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1151  *           *probe_one, *_console, *_timer
1152  *
1153  * Pattern 3:
1154  *   Whitelist all references from .head.text to any init section
1155  *
1156  * Pattern 4:
1157  *   Some symbols belong to init section but still it is ok to reference
1158  *   these from non-init sections as these symbols don't have any memory
1159  *   allocated for them and symbol address and value are same. So even
1160  *   if init section is freed, its ok to reference those symbols.
1161  *   For ex. symbols marking the init section boundaries.
1162  *   This pattern is identified by
1163  *   refsymname = __init_begin, _sinittext, _einittext
1164  *
1165  * Pattern 5:
1166  *   GCC may optimize static inlines when fed constant arg(s) resulting
1167  *   in functions like cpumask_empty() -- generating an associated symbol
1168  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
1169  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
1170  *   meaningless section warning.  May need to add isra symbols too...
1171  *   This pattern is identified by
1172  *   tosec   = init section
1173  *   fromsec = text section
1174  *   refsymname = *.constprop.*
1175  *
1176  **/
1177 static int secref_whitelist(const struct sectioncheck *mismatch,
1178                             const char *fromsec, const char *fromsym,
1179                             const char *tosec, const char *tosym)
1180 {
1181         /* Check for pattern 1 */
1182         if (match(tosec, init_data_sections) &&
1183             match(fromsec, data_sections) &&
1184             (strncmp(fromsym, "__param", strlen("__param")) == 0))
1185                 return 0;
1186
1187         /* Check for pattern 1a */
1188         if (strcmp(tosec, ".init.text") == 0 &&
1189             match(fromsec, data_sections) &&
1190             (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1191                 return 0;
1192
1193         /* Check for pattern 2 */
1194         if (match(tosec, init_exit_sections) &&
1195             match(fromsec, data_sections) &&
1196             match(fromsym, mismatch->symbol_white_list))
1197                 return 0;
1198
1199         /* Check for pattern 3 */
1200         if (match(fromsec, head_sections) &&
1201             match(tosec, init_sections))
1202                 return 0;
1203
1204         /* Check for pattern 4 */
1205         if (match(tosym, linker_symbols))
1206                 return 0;
1207
1208         /* Check for pattern 5 */
1209         if (match(fromsec, text_sections) &&
1210             match(tosec, init_sections) &&
1211             match(fromsym, optim_symbols))
1212                 return 0;
1213
1214         return 1;
1215 }
1216
1217 /**
1218  * Find symbol based on relocation record info.
1219  * In some cases the symbol supplied is a valid symbol so
1220  * return refsym. If st_name != 0 we assume this is a valid symbol.
1221  * In other cases the symbol needs to be looked up in the symbol table
1222  * based on section and address.
1223  *  **/
1224 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1225                                 Elf_Sym *relsym)
1226 {
1227         Elf_Sym *sym;
1228         Elf_Sym *near = NULL;
1229         Elf64_Sword distance = 20;
1230         Elf64_Sword d;
1231         unsigned int relsym_secindex;
1232
1233         if (relsym->st_name != 0)
1234                 return relsym;
1235
1236         relsym_secindex = get_secindex(elf, relsym);
1237         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1238                 if (get_secindex(elf, sym) != relsym_secindex)
1239                         continue;
1240                 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1241                         continue;
1242                 if (sym->st_value == addr)
1243                         return sym;
1244                 /* Find a symbol nearby - addr are maybe negative */
1245                 d = sym->st_value - addr;
1246                 if (d < 0)
1247                         d = addr - sym->st_value;
1248                 if (d < distance) {
1249                         distance = d;
1250                         near = sym;
1251                 }
1252         }
1253         /* We need a close match */
1254         if (distance < 20)
1255                 return near;
1256         else
1257                 return NULL;
1258 }
1259
1260 static inline int is_arm_mapping_symbol(const char *str)
1261 {
1262         return str[0] == '$' && strchr("axtd", str[1])
1263                && (str[2] == '\0' || str[2] == '.');
1264 }
1265
1266 /*
1267  * If there's no name there, ignore it; likewise, ignore it if it's
1268  * one of the magic symbols emitted used by current ARM tools.
1269  *
1270  * Otherwise if find_symbols_between() returns those symbols, they'll
1271  * fail the whitelist tests and cause lots of false alarms ... fixable
1272  * only by merging __exit and __init sections into __text, bloating
1273  * the kernel (which is especially evil on embedded platforms).
1274  */
1275 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1276 {
1277         const char *name = elf->strtab + sym->st_name;
1278
1279         if (!name || !strlen(name))
1280                 return 0;
1281         return !is_arm_mapping_symbol(name);
1282 }
1283
1284 /*
1285  * Find symbols before or equal addr and after addr - in the section sec.
1286  * If we find two symbols with equal offset prefer one with a valid name.
1287  * The ELF format may have a better way to detect what type of symbol
1288  * it is, but this works for now.
1289  **/
1290 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1291                                  const char *sec)
1292 {
1293         Elf_Sym *sym;
1294         Elf_Sym *near = NULL;
1295         Elf_Addr distance = ~0;
1296
1297         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1298                 const char *symsec;
1299
1300                 if (is_shndx_special(sym->st_shndx))
1301                         continue;
1302                 symsec = sec_name(elf, get_secindex(elf, sym));
1303                 if (strcmp(symsec, sec) != 0)
1304                         continue;
1305                 if (!is_valid_name(elf, sym))
1306                         continue;
1307                 if (sym->st_value <= addr) {
1308                         if ((addr - sym->st_value) < distance) {
1309                                 distance = addr - sym->st_value;
1310                                 near = sym;
1311                         } else if ((addr - sym->st_value) == distance) {
1312                                 near = sym;
1313                         }
1314                 }
1315         }
1316         return near;
1317 }
1318
1319 /*
1320  * Convert a section name to the function/data attribute
1321  * .init.text => __init
1322  * .memexitconst => __memconst
1323  * etc.
1324  *
1325  * The memory of returned value has been allocated on a heap. The user of this
1326  * method should free it after usage.
1327 */
1328 static char *sec2annotation(const char *s)
1329 {
1330         if (match(s, init_exit_sections)) {
1331                 char *p = malloc(20);
1332                 char *r = p;
1333
1334                 *p++ = '_';
1335                 *p++ = '_';
1336                 if (*s == '.')
1337                         s++;
1338                 while (*s && *s != '.')
1339                         *p++ = *s++;
1340                 *p = '\0';
1341                 if (*s == '.')
1342                         s++;
1343                 if (strstr(s, "rodata") != NULL)
1344                         strcat(p, "const ");
1345                 else if (strstr(s, "data") != NULL)
1346                         strcat(p, "data ");
1347                 else
1348                         strcat(p, " ");
1349                 return r;
1350         } else {
1351                 return strdup("");
1352         }
1353 }
1354
1355 static int is_function(Elf_Sym *sym)
1356 {
1357         if (sym)
1358                 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1359         else
1360                 return -1;
1361 }
1362
1363 static void print_section_list(const char * const list[20])
1364 {
1365         const char *const *s = list;
1366
1367         while (*s) {
1368                 fprintf(stderr, "%s", *s);
1369                 s++;
1370                 if (*s)
1371                         fprintf(stderr, ", ");
1372         }
1373         fprintf(stderr, "\n");
1374 }
1375
1376 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1377 {
1378         switch (is_func) {
1379         case 0: *name = "variable"; *name_p = ""; break;
1380         case 1: *name = "function"; *name_p = "()"; break;
1381         default: *name = "(unknown reference)"; *name_p = ""; break;
1382         }
1383 }
1384
1385 /*
1386  * Print a warning about a section mismatch.
1387  * Try to find symbols near it so user can find it.
1388  * Check whitelist before warning - it may be a false positive.
1389  */
1390 static void report_sec_mismatch(const char *modname,
1391                                 const struct sectioncheck *mismatch,
1392                                 const char *fromsec,
1393                                 unsigned long long fromaddr,
1394                                 const char *fromsym,
1395                                 int from_is_func,
1396                                 const char *tosec, const char *tosym,
1397                                 int to_is_func)
1398 {
1399         const char *from, *from_p;
1400         const char *to, *to_p;
1401         char *prl_from;
1402         char *prl_to;
1403
1404         sec_mismatch_count++;
1405         if (!sec_mismatch_verbose)
1406                 return;
1407
1408         get_pretty_name(from_is_func, &from, &from_p);
1409         get_pretty_name(to_is_func, &to, &to_p);
1410
1411         warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1412              "to the %s %s:%s%s\n",
1413              modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1414              tosym, to_p);
1415
1416         switch (mismatch->mismatch) {
1417         case TEXT_TO_ANY_INIT:
1418                 prl_from = sec2annotation(fromsec);
1419                 prl_to = sec2annotation(tosec);
1420                 fprintf(stderr,
1421                 "The function %s%s() references\n"
1422                 "the %s %s%s%s.\n"
1423                 "This is often because %s lacks a %s\n"
1424                 "annotation or the annotation of %s is wrong.\n",
1425                 prl_from, fromsym,
1426                 to, prl_to, tosym, to_p,
1427                 fromsym, prl_to, tosym);
1428                 free(prl_from);
1429                 free(prl_to);
1430                 break;
1431         case DATA_TO_ANY_INIT: {
1432                 prl_to = sec2annotation(tosec);
1433                 fprintf(stderr,
1434                 "The variable %s references\n"
1435                 "the %s %s%s%s\n"
1436                 "If the reference is valid then annotate the\n"
1437                 "variable with __init* or __refdata (see linux/init.h) "
1438                 "or name the variable:\n",
1439                 fromsym, to, prl_to, tosym, to_p);
1440                 print_section_list(mismatch->symbol_white_list);
1441                 free(prl_to);
1442                 break;
1443         }
1444         case TEXT_TO_ANY_EXIT:
1445                 prl_to = sec2annotation(tosec);
1446                 fprintf(stderr,
1447                 "The function %s() references a %s in an exit section.\n"
1448                 "Often the %s %s%s has valid usage outside the exit section\n"
1449                 "and the fix is to remove the %sannotation of %s.\n",
1450                 fromsym, to, to, tosym, to_p, prl_to, tosym);
1451                 free(prl_to);
1452                 break;
1453         case DATA_TO_ANY_EXIT: {
1454                 prl_to = sec2annotation(tosec);
1455                 fprintf(stderr,
1456                 "The variable %s references\n"
1457                 "the %s %s%s%s\n"
1458                 "If the reference is valid then annotate the\n"
1459                 "variable with __exit* (see linux/init.h) or "
1460                 "name the variable:\n",
1461                 fromsym, to, prl_to, tosym, to_p);
1462                 print_section_list(mismatch->symbol_white_list);
1463                 free(prl_to);
1464                 break;
1465         }
1466         case XXXINIT_TO_SOME_INIT:
1467         case XXXEXIT_TO_SOME_EXIT:
1468                 prl_from = sec2annotation(fromsec);
1469                 prl_to = sec2annotation(tosec);
1470                 fprintf(stderr,
1471                 "The %s %s%s%s references\n"
1472                 "a %s %s%s%s.\n"
1473                 "If %s is only used by %s then\n"
1474                 "annotate %s with a matching annotation.\n",
1475                 from, prl_from, fromsym, from_p,
1476                 to, prl_to, tosym, to_p,
1477                 tosym, fromsym, tosym);
1478                 free(prl_from);
1479                 free(prl_to);
1480                 break;
1481         case ANY_INIT_TO_ANY_EXIT:
1482                 prl_from = sec2annotation(fromsec);
1483                 prl_to = sec2annotation(tosec);
1484                 fprintf(stderr,
1485                 "The %s %s%s%s references\n"
1486                 "a %s %s%s%s.\n"
1487                 "This is often seen when error handling "
1488                 "in the init function\n"
1489                 "uses functionality in the exit path.\n"
1490                 "The fix is often to remove the %sannotation of\n"
1491                 "%s%s so it may be used outside an exit section.\n",
1492                 from, prl_from, fromsym, from_p,
1493                 to, prl_to, tosym, to_p,
1494                 prl_to, tosym, to_p);
1495                 free(prl_from);
1496                 free(prl_to);
1497                 break;
1498         case ANY_EXIT_TO_ANY_INIT:
1499                 prl_from = sec2annotation(fromsec);
1500                 prl_to = sec2annotation(tosec);
1501                 fprintf(stderr,
1502                 "The %s %s%s%s references\n"
1503                 "a %s %s%s%s.\n"
1504                 "This is often seen when error handling "
1505                 "in the exit function\n"
1506                 "uses functionality in the init path.\n"
1507                 "The fix is often to remove the %sannotation of\n"
1508                 "%s%s so it may be used outside an init section.\n",
1509                 from, prl_from, fromsym, from_p,
1510                 to, prl_to, tosym, to_p,
1511                 prl_to, tosym, to_p);
1512                 free(prl_from);
1513                 free(prl_to);
1514                 break;
1515         case EXPORT_TO_INIT_EXIT:
1516                 prl_to = sec2annotation(tosec);
1517                 fprintf(stderr,
1518                 "The symbol %s is exported and annotated %s\n"
1519                 "Fix this by removing the %sannotation of %s "
1520                 "or drop the export.\n",
1521                 tosym, prl_to, prl_to, tosym);
1522                 free(prl_to);
1523                 break;
1524         case EXTABLE_TO_NON_TEXT:
1525                 fatal("There's a special handler for this mismatch type, "
1526                       "we should never get here.");
1527                 break;
1528         }
1529         fprintf(stderr, "\n");
1530 }
1531
1532 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1533                                      const struct sectioncheck* const mismatch,
1534                                      Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1535 {
1536         const char *tosec;
1537         Elf_Sym *to;
1538         Elf_Sym *from;
1539         const char *tosym;
1540         const char *fromsym;
1541
1542         from = find_elf_symbol2(elf, r->r_offset, fromsec);
1543         fromsym = sym_name(elf, from);
1544
1545         if (!strncmp(fromsym, "reference___initcall",
1546                      sizeof("reference___initcall")-1))
1547                 return;
1548
1549         tosec = sec_name(elf, get_secindex(elf, sym));
1550         to = find_elf_symbol(elf, r->r_addend, sym);
1551         tosym = sym_name(elf, to);
1552
1553         /* check whitelist - we may ignore it */
1554         if (secref_whitelist(mismatch,
1555                              fromsec, fromsym, tosec, tosym)) {
1556                 report_sec_mismatch(modname, mismatch,
1557                                     fromsec, r->r_offset, fromsym,
1558                                     is_function(from), tosec, tosym,
1559                                     is_function(to));
1560         }
1561 }
1562
1563 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1564 {
1565         if (section_index > elf->num_sections)
1566                 fatal("section_index is outside elf->num_sections!\n");
1567
1568         return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1569 }
1570
1571 /*
1572  * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1573  * to know the sizeof(struct exception_table_entry) for the target architecture.
1574  */
1575 static unsigned int extable_entry_size = 0;
1576 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1577 {
1578         /*
1579          * If we're currently checking the second relocation within __ex_table,
1580          * that relocation offset tells us the offsetof(struct
1581          * exception_table_entry, fixup) which is equal to sizeof(struct
1582          * exception_table_entry) divided by two.  We use that to our advantage
1583          * since there's no portable way to get that size as every architecture
1584          * seems to go with different sized types.  Not pretty but better than
1585          * hard-coding the size for every architecture..
1586          */
1587         if (!extable_entry_size)
1588                 extable_entry_size = r->r_offset * 2;
1589 }
1590
1591 static inline bool is_extable_fault_address(Elf_Rela *r)
1592 {
1593         /*
1594          * extable_entry_size is only discovered after we've handled the
1595          * _second_ relocation in __ex_table, so only abort when we're not
1596          * handling the first reloc and extable_entry_size is zero.
1597          */
1598         if (r->r_offset && extable_entry_size == 0)
1599                 fatal("extable_entry size hasn't been discovered!\n");
1600
1601         return ((r->r_offset == 0) ||
1602                 (r->r_offset % extable_entry_size == 0));
1603 }
1604
1605 #define is_second_extable_reloc(Start, Cur, Sec)                        \
1606         (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1607
1608 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1609                                     const struct sectioncheck* const mismatch,
1610                                     Elf_Rela* r, Elf_Sym* sym,
1611                                     const char* fromsec, const char* tosec)
1612 {
1613         Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1614         const char* fromsym_name = sym_name(elf, fromsym);
1615         Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1616         const char* tosym_name = sym_name(elf, tosym);
1617         const char* from_pretty_name;
1618         const char* from_pretty_name_p;
1619         const char* to_pretty_name;
1620         const char* to_pretty_name_p;
1621
1622         get_pretty_name(is_function(fromsym),
1623                         &from_pretty_name, &from_pretty_name_p);
1624         get_pretty_name(is_function(tosym),
1625                         &to_pretty_name, &to_pretty_name_p);
1626
1627         warn("%s(%s+0x%lx): Section mismatch in reference"
1628              " from the %s %s%s to the %s %s:%s%s\n",
1629              modname, fromsec, (long)r->r_offset, from_pretty_name,
1630              fromsym_name, from_pretty_name_p,
1631              to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1632
1633         if (!match(tosec, mismatch->bad_tosec) &&
1634             is_executable_section(elf, get_secindex(elf, sym)))
1635                 fprintf(stderr,
1636                         "The relocation at %s+0x%lx references\n"
1637                         "section \"%s\" which is not in the list of\n"
1638                         "authorized sections.  If you're adding a new section\n"
1639                         "and/or if this reference is valid, add \"%s\" to the\n"
1640                         "list of authorized sections to jump to on fault.\n"
1641                         "This can be achieved by adding \"%s\" to \n"
1642                         "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1643                         fromsec, (long)r->r_offset, tosec, tosec, tosec);
1644 }
1645
1646 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1647                                      const struct sectioncheck* const mismatch,
1648                                      Elf_Rela* r, Elf_Sym* sym,
1649                                      const char *fromsec)
1650 {
1651         const char* tosec = sec_name(elf, get_secindex(elf, sym));
1652
1653         sec_mismatch_count++;
1654
1655         if (sec_mismatch_verbose)
1656                 report_extable_warnings(modname, elf, mismatch, r, sym,
1657                                         fromsec, tosec);
1658
1659         if (match(tosec, mismatch->bad_tosec))
1660                 fatal("The relocation at %s+0x%lx references\n"
1661                       "section \"%s\" which is black-listed.\n"
1662                       "Something is seriously wrong and should be fixed.\n"
1663                       "You might get more information about where this is\n"
1664                       "coming from by using scripts/check_extable.sh %s\n",
1665                       fromsec, (long)r->r_offset, tosec, modname);
1666         else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1667                 if (is_extable_fault_address(r))
1668                         fatal("The relocation at %s+0x%lx references\n"
1669                               "section \"%s\" which is not executable, IOW\n"
1670                               "it is not possible for the kernel to fault\n"
1671                               "at that address.  Something is seriously wrong\n"
1672                               "and should be fixed.\n",
1673                               fromsec, (long)r->r_offset, tosec);
1674                 else
1675                         fatal("The relocation at %s+0x%lx references\n"
1676                               "section \"%s\" which is not executable, IOW\n"
1677                               "the kernel will fault if it ever tries to\n"
1678                               "jump to it.  Something is seriously wrong\n"
1679                               "and should be fixed.\n",
1680                               fromsec, (long)r->r_offset, tosec);
1681         }
1682 }
1683
1684 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1685                                    Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1686 {
1687         const char *tosec = sec_name(elf, get_secindex(elf, sym));
1688         const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1689
1690         if (mismatch) {
1691                 if (mismatch->handler)
1692                         mismatch->handler(modname, elf,  mismatch,
1693                                           r, sym, fromsec);
1694                 else
1695                         default_mismatch_handler(modname, elf, mismatch,
1696                                                  r, sym, fromsec);
1697         }
1698 }
1699
1700 static unsigned int *reloc_location(struct elf_info *elf,
1701                                     Elf_Shdr *sechdr, Elf_Rela *r)
1702 {
1703         Elf_Shdr *sechdrs = elf->sechdrs;
1704         int section = sechdr->sh_info;
1705
1706         return (void *)elf->hdr + sechdrs[section].sh_offset +
1707                 r->r_offset;
1708 }
1709
1710 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1711 {
1712         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1713         unsigned int *location = reloc_location(elf, sechdr, r);
1714
1715         switch (r_typ) {
1716         case R_386_32:
1717                 r->r_addend = TO_NATIVE(*location);
1718                 break;
1719         case R_386_PC32:
1720                 r->r_addend = TO_NATIVE(*location) + 4;
1721                 /* For CONFIG_RELOCATABLE=y */
1722                 if (elf->hdr->e_type == ET_EXEC)
1723                         r->r_addend += r->r_offset;
1724                 break;
1725         }
1726         return 0;
1727 }
1728
1729 #ifndef R_ARM_CALL
1730 #define R_ARM_CALL      28
1731 #endif
1732 #ifndef R_ARM_JUMP24
1733 #define R_ARM_JUMP24    29
1734 #endif
1735
1736 #ifndef R_ARM_THM_CALL
1737 #define R_ARM_THM_CALL          10
1738 #endif
1739 #ifndef R_ARM_THM_JUMP24
1740 #define R_ARM_THM_JUMP24        30
1741 #endif
1742 #ifndef R_ARM_THM_JUMP19
1743 #define R_ARM_THM_JUMP19        51
1744 #endif
1745
1746 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1747 {
1748         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1749
1750         switch (r_typ) {
1751         case R_ARM_ABS32:
1752                 /* From ARM ABI: (S + A) | T */
1753                 r->r_addend = (int)(long)
1754                               (elf->symtab_start + ELF_R_SYM(r->r_info));
1755                 break;
1756         case R_ARM_PC24:
1757         case R_ARM_CALL:
1758         case R_ARM_JUMP24:
1759         case R_ARM_THM_CALL:
1760         case R_ARM_THM_JUMP24:
1761         case R_ARM_THM_JUMP19:
1762                 /* From ARM ABI: ((S + A) | T) - P */
1763                 r->r_addend = (int)(long)(elf->hdr +
1764                               sechdr->sh_offset +
1765                               (r->r_offset - sechdr->sh_addr));
1766                 break;
1767         default:
1768                 return 1;
1769         }
1770         return 0;
1771 }
1772
1773 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1774 {
1775         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1776         unsigned int *location = reloc_location(elf, sechdr, r);
1777         unsigned int inst;
1778
1779         if (r_typ == R_MIPS_HI16)
1780                 return 1;       /* skip this */
1781         inst = TO_NATIVE(*location);
1782         switch (r_typ) {
1783         case R_MIPS_LO16:
1784                 r->r_addend = inst & 0xffff;
1785                 break;
1786         case R_MIPS_26:
1787                 r->r_addend = (inst & 0x03ffffff) << 2;
1788                 break;
1789         case R_MIPS_32:
1790                 r->r_addend = inst;
1791                 break;
1792         }
1793         return 0;
1794 }
1795
1796 static void section_rela(const char *modname, struct elf_info *elf,
1797                          Elf_Shdr *sechdr)
1798 {
1799         Elf_Sym  *sym;
1800         Elf_Rela *rela;
1801         Elf_Rela r;
1802         unsigned int r_sym;
1803         const char *fromsec;
1804
1805         Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1806         Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1807
1808         fromsec = sech_name(elf, sechdr);
1809         fromsec += strlen(".rela");
1810         /* if from section (name) is know good then skip it */
1811         if (match(fromsec, section_white_list))
1812                 return;
1813
1814         for (rela = start; rela < stop; rela++) {
1815                 r.r_offset = TO_NATIVE(rela->r_offset);
1816 #if KERNEL_ELFCLASS == ELFCLASS64
1817                 if (elf->hdr->e_machine == EM_MIPS) {
1818                         unsigned int r_typ;
1819                         r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1820                         r_sym = TO_NATIVE(r_sym);
1821                         r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1822                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1823                 } else {
1824                         r.r_info = TO_NATIVE(rela->r_info);
1825                         r_sym = ELF_R_SYM(r.r_info);
1826                 }
1827 #else
1828                 r.r_info = TO_NATIVE(rela->r_info);
1829                 r_sym = ELF_R_SYM(r.r_info);
1830 #endif
1831                 r.r_addend = TO_NATIVE(rela->r_addend);
1832                 sym = elf->symtab_start + r_sym;
1833                 /* Skip special sections */
1834                 if (is_shndx_special(sym->st_shndx))
1835                         continue;
1836                 if (is_second_extable_reloc(start, rela, fromsec))
1837                         find_extable_entry_size(fromsec, &r);
1838                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1839         }
1840 }
1841
1842 static void section_rel(const char *modname, struct elf_info *elf,
1843                         Elf_Shdr *sechdr)
1844 {
1845         Elf_Sym *sym;
1846         Elf_Rel *rel;
1847         Elf_Rela r;
1848         unsigned int r_sym;
1849         const char *fromsec;
1850
1851         Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1852         Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1853
1854         fromsec = sech_name(elf, sechdr);
1855         fromsec += strlen(".rel");
1856         /* if from section (name) is know good then skip it */
1857         if (match(fromsec, section_white_list))
1858                 return;
1859
1860         for (rel = start; rel < stop; rel++) {
1861                 r.r_offset = TO_NATIVE(rel->r_offset);
1862 #if KERNEL_ELFCLASS == ELFCLASS64
1863                 if (elf->hdr->e_machine == EM_MIPS) {
1864                         unsigned int r_typ;
1865                         r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1866                         r_sym = TO_NATIVE(r_sym);
1867                         r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1868                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1869                 } else {
1870                         r.r_info = TO_NATIVE(rel->r_info);
1871                         r_sym = ELF_R_SYM(r.r_info);
1872                 }
1873 #else
1874                 r.r_info = TO_NATIVE(rel->r_info);
1875                 r_sym = ELF_R_SYM(r.r_info);
1876 #endif
1877                 r.r_addend = 0;
1878                 switch (elf->hdr->e_machine) {
1879                 case EM_386:
1880                         if (addend_386_rel(elf, sechdr, &r))
1881                                 continue;
1882                         break;
1883                 case EM_ARM:
1884                         if (addend_arm_rel(elf, sechdr, &r))
1885                                 continue;
1886                         break;
1887                 case EM_MIPS:
1888                         if (addend_mips_rel(elf, sechdr, &r))
1889                                 continue;
1890                         break;
1891                 }
1892                 sym = elf->symtab_start + r_sym;
1893                 /* Skip special sections */
1894                 if (is_shndx_special(sym->st_shndx))
1895                         continue;
1896                 if (is_second_extable_reloc(start, rel, fromsec))
1897                         find_extable_entry_size(fromsec, &r);
1898                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1899         }
1900 }
1901
1902 /**
1903  * A module includes a number of sections that are discarded
1904  * either when loaded or when used as built-in.
1905  * For loaded modules all functions marked __init and all data
1906  * marked __initdata will be discarded when the module has been initialized.
1907  * Likewise for modules used built-in the sections marked __exit
1908  * are discarded because __exit marked function are supposed to be called
1909  * only when a module is unloaded which never happens for built-in modules.
1910  * The check_sec_ref() function traverses all relocation records
1911  * to find all references to a section that reference a section that will
1912  * be discarded and warns about it.
1913  **/
1914 static void check_sec_ref(struct module *mod, const char *modname,
1915                           struct elf_info *elf)
1916 {
1917         int i;
1918         Elf_Shdr *sechdrs = elf->sechdrs;
1919
1920         /* Walk through all sections */
1921         for (i = 0; i < elf->num_sections; i++) {
1922                 check_section(modname, elf, &elf->sechdrs[i]);
1923                 /* We want to process only relocation sections and not .init */
1924                 if (sechdrs[i].sh_type == SHT_RELA)
1925                         section_rela(modname, elf, &elf->sechdrs[i]);
1926                 else if (sechdrs[i].sh_type == SHT_REL)
1927                         section_rel(modname, elf, &elf->sechdrs[i]);
1928         }
1929 }
1930
1931 static char *remove_dot(char *s)
1932 {
1933         size_t n = strcspn(s, ".");
1934
1935         if (n && s[n]) {
1936                 size_t m = strspn(s + n + 1, "0123456789");
1937                 if (m && (s[n + m] == '.' || s[n + m] == 0))
1938                         s[n] = 0;
1939         }
1940         return s;
1941 }
1942
1943 static void read_symbols(char *modname)
1944 {
1945         const char *symname;
1946         char *version;
1947         char *license;
1948         struct module *mod;
1949         struct elf_info info = { };
1950         Elf_Sym *sym;
1951
1952         if (!parse_elf(&info, modname))
1953                 return;
1954
1955         mod = new_module(modname);
1956
1957         /* When there's no vmlinux, don't print warnings about
1958          * unresolved symbols (since there'll be too many ;) */
1959         if (is_vmlinux(modname)) {
1960                 have_vmlinux = 1;
1961                 mod->skip = 1;
1962         }
1963
1964         license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1965         if (!license && !is_vmlinux(modname))
1966                 warn("modpost: missing MODULE_LICENSE() in %s\n"
1967                      "see include/linux/module.h for "
1968                      "more information\n", modname);
1969         while (license) {
1970                 if (license_is_gpl_compatible(license))
1971                         mod->gpl_compatible = 1;
1972                 else {
1973                         mod->gpl_compatible = 0;
1974                         break;
1975                 }
1976                 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1977                                            "license", license);
1978         }
1979
1980         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1981                 symname = remove_dot(info.strtab + sym->st_name);
1982
1983                 handle_modversions(mod, &info, sym, symname);
1984                 handle_moddevtable(mod, &info, sym, symname);
1985         }
1986         if (!is_vmlinux(modname) ||
1987              (is_vmlinux(modname) && vmlinux_section_warnings))
1988                 check_sec_ref(mod, modname, &info);
1989
1990         version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1991         if (version)
1992                 maybe_frob_rcs_version(modname, version, info.modinfo,
1993                                        version - (char *)info.hdr);
1994         if (version || (all_versions && !is_vmlinux(modname)))
1995                 get_src_version(modname, mod->srcversion,
1996                                 sizeof(mod->srcversion)-1);
1997
1998         parse_elf_finish(&info);
1999
2000         /* Our trick to get versioning for module struct etc. - it's
2001          * never passed as an argument to an exported function, so
2002          * the automatic versioning doesn't pick it up, but it's really
2003          * important anyhow */
2004         if (modversions)
2005                 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2006 }
2007
2008 static void read_symbols_from_files(const char *filename)
2009 {
2010         FILE *in = stdin;
2011         char fname[PATH_MAX];
2012
2013         if (strcmp(filename, "-") != 0) {
2014                 in = fopen(filename, "r");
2015                 if (!in)
2016                         fatal("Can't open filenames file %s: %m", filename);
2017         }
2018
2019         while (fgets(fname, PATH_MAX, in) != NULL) {
2020                 if (strends(fname, "\n"))
2021                         fname[strlen(fname)-1] = '\0';
2022                 read_symbols(fname);
2023         }
2024
2025         if (in != stdin)
2026                 fclose(in);
2027 }
2028
2029 #define SZ 500
2030
2031 /* We first write the generated file into memory using the
2032  * following helper, then compare to the file on disk and
2033  * only update the later if anything changed */
2034
2035 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2036                                                       const char *fmt, ...)
2037 {
2038         char tmp[SZ];
2039         int len;
2040         va_list ap;
2041
2042         va_start(ap, fmt);
2043         len = vsnprintf(tmp, SZ, fmt, ap);
2044         buf_write(buf, tmp, len);
2045         va_end(ap);
2046 }
2047
2048 void buf_write(struct buffer *buf, const char *s, int len)
2049 {
2050         if (buf->size - buf->pos < len) {
2051                 buf->size += len + SZ;
2052                 buf->p = realloc(buf->p, buf->size);
2053         }
2054         strncpy(buf->p + buf->pos, s, len);
2055         buf->pos += len;
2056 }
2057
2058 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2059 {
2060         const char *e = is_vmlinux(m) ?"":".ko";
2061
2062         switch (exp) {
2063         case export_gpl:
2064                 fatal("modpost: GPL-incompatible module %s%s "
2065                       "uses GPL-only symbol '%s'\n", m, e, s);
2066                 break;
2067         case export_unused_gpl:
2068                 fatal("modpost: GPL-incompatible module %s%s "
2069                       "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2070                 break;
2071         case export_gpl_future:
2072                 warn("modpost: GPL-incompatible module %s%s "
2073                       "uses future GPL-only symbol '%s'\n", m, e, s);
2074                 break;
2075         case export_plain:
2076         case export_unused:
2077         case export_unknown:
2078                 /* ignore */
2079                 break;
2080         }
2081 }
2082
2083 static void check_for_unused(enum export exp, const char *m, const char *s)
2084 {
2085         const char *e = is_vmlinux(m) ?"":".ko";
2086
2087         switch (exp) {
2088         case export_unused:
2089         case export_unused_gpl:
2090                 warn("modpost: module %s%s "
2091                       "uses symbol '%s' marked UNUSED\n", m, e, s);
2092                 break;
2093         default:
2094                 /* ignore */
2095                 break;
2096         }
2097 }
2098
2099 static void check_exports(struct module *mod)
2100 {
2101         struct symbol *s, *exp;
2102
2103         for (s = mod->unres; s; s = s->next) {
2104                 const char *basename;
2105                 exp = find_symbol(s->name);
2106                 if (!exp || exp->module == mod)
2107                         continue;
2108                 basename = strrchr(mod->name, '/');
2109                 if (basename)
2110                         basename++;
2111                 else
2112                         basename = mod->name;
2113                 if (!mod->gpl_compatible)
2114                         check_for_gpl_usage(exp->export, basename, exp->name);
2115                 check_for_unused(exp->export, basename, exp->name);
2116         }
2117 }
2118
2119 static int check_modname_len(struct module *mod)
2120 {
2121         const char *mod_name;
2122
2123         mod_name = strrchr(mod->name, '/');
2124         if (mod_name == NULL)
2125                 mod_name = mod->name;
2126         else
2127                 mod_name++;
2128         if (strlen(mod_name) >= MODULE_NAME_LEN) {
2129                 merror("module name is too long [%s.ko]\n", mod->name);
2130                 return 1;
2131         }
2132
2133         return 0;
2134 }
2135
2136 /**
2137  * Header for the generated file
2138  **/
2139 static void add_header(struct buffer *b, struct module *mod)
2140 {
2141         buf_printf(b, "#include <linux/module.h>\n");
2142         buf_printf(b, "#include <linux/vermagic.h>\n");
2143         buf_printf(b, "#include <linux/compiler.h>\n");
2144         buf_printf(b, "\n");
2145         buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2146         buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2147         buf_printf(b, "\n");
2148         buf_printf(b, "__visible struct module __this_module\n");
2149         buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2150         buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2151         if (mod->has_init)
2152                 buf_printf(b, "\t.init = init_module,\n");
2153         if (mod->has_cleanup)
2154                 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2155                               "\t.exit = cleanup_module,\n"
2156                               "#endif\n");
2157         buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2158         buf_printf(b, "};\n");
2159 }
2160
2161 static void add_intree_flag(struct buffer *b, int is_intree)
2162 {
2163         if (is_intree)
2164                 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2165 }
2166
2167 /* Cannot check for assembler */
2168 static void add_retpoline(struct buffer *b)
2169 {
2170         buf_printf(b, "\n#ifdef RETPOLINE\n");
2171         buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2172         buf_printf(b, "#endif\n");
2173 }
2174
2175 static void add_staging_flag(struct buffer *b, const char *name)
2176 {
2177         static const char *staging_dir = "drivers/staging";
2178
2179         if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2180                 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2181 }
2182
2183 /**
2184  * Record CRCs for unresolved symbols
2185  **/
2186 static int add_versions(struct buffer *b, struct module *mod)
2187 {
2188         struct symbol *s, *exp;
2189         int err = 0;
2190
2191         for (s = mod->unres; s; s = s->next) {
2192                 exp = find_symbol(s->name);
2193                 if (!exp || exp->module == mod) {
2194                         if (have_vmlinux && !s->weak) {
2195                                 if (warn_unresolved) {
2196                                         warn("\"%s\" [%s.ko] undefined!\n",
2197                                              s->name, mod->name);
2198                                 } else {
2199                                         merror("\"%s\" [%s.ko] undefined!\n",
2200                                                s->name, mod->name);
2201                                         err = 1;
2202                                 }
2203                         }
2204                         continue;
2205                 }
2206                 s->module = exp->module;
2207                 s->crc_valid = exp->crc_valid;
2208                 s->crc = exp->crc;
2209         }
2210
2211         if (!modversions)
2212                 return err;
2213
2214         buf_printf(b, "\n");
2215         buf_printf(b, "static const struct modversion_info ____versions[]\n");
2216         buf_printf(b, "__used\n");
2217         buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2218
2219         for (s = mod->unres; s; s = s->next) {
2220                 if (!s->module)
2221                         continue;
2222                 if (!s->crc_valid) {
2223                         warn("\"%s\" [%s.ko] has no CRC!\n",
2224                                 s->name, mod->name);
2225                         continue;
2226                 }
2227                 if (strlen(s->name) >= MODULE_NAME_LEN) {
2228                         merror("too long symbol \"%s\" [%s.ko]\n",
2229                                s->name, mod->name);
2230                         err = 1;
2231                         break;
2232                 }
2233                 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2234                            s->crc, s->name);
2235         }
2236
2237         buf_printf(b, "};\n");
2238
2239         return err;
2240 }
2241
2242 static void add_depends(struct buffer *b, struct module *mod,
2243                         struct module *modules)
2244 {
2245         struct symbol *s;
2246         struct module *m;
2247         int first = 1;
2248
2249         for (m = modules; m; m = m->next)
2250                 m->seen = is_vmlinux(m->name);
2251
2252         buf_printf(b, "\n");
2253         buf_printf(b, "static const char __module_depends[]\n");
2254         buf_printf(b, "__used\n");
2255         buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2256         buf_printf(b, "\"depends=");
2257         for (s = mod->unres; s; s = s->next) {
2258                 const char *p;
2259                 if (!s->module)
2260                         continue;
2261
2262                 if (s->module->seen)
2263                         continue;
2264
2265                 s->module->seen = 1;
2266                 p = strrchr(s->module->name, '/');
2267                 if (p)
2268                         p++;
2269                 else
2270                         p = s->module->name;
2271                 buf_printf(b, "%s%s", first ? "" : ",", p);
2272                 first = 0;
2273         }
2274         buf_printf(b, "\";\n");
2275 }
2276
2277 static void add_srcversion(struct buffer *b, struct module *mod)
2278 {
2279         if (mod->srcversion[0]) {
2280                 buf_printf(b, "\n");
2281                 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2282                            mod->srcversion);
2283         }
2284 }
2285
2286 static void write_if_changed(struct buffer *b, const char *fname)
2287 {
2288         char *tmp;
2289         FILE *file;
2290         struct stat st;
2291
2292         file = fopen(fname, "r");
2293         if (!file)
2294                 goto write;
2295
2296         if (fstat(fileno(file), &st) < 0)
2297                 goto close_write;
2298
2299         if (st.st_size != b->pos)
2300                 goto close_write;
2301
2302         tmp = NOFAIL(malloc(b->pos));
2303         if (fread(tmp, 1, b->pos, file) != b->pos)
2304                 goto free_write;
2305
2306         if (memcmp(tmp, b->p, b->pos) != 0)
2307                 goto free_write;
2308
2309         free(tmp);
2310         fclose(file);
2311         return;
2312
2313  free_write:
2314         free(tmp);
2315  close_write:
2316         fclose(file);
2317  write:
2318         file = fopen(fname, "w");
2319         if (!file) {
2320                 perror(fname);
2321                 exit(1);
2322         }
2323         if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2324                 perror(fname);
2325                 exit(1);
2326         }
2327         fclose(file);
2328 }
2329
2330 /* parse Module.symvers file. line format:
2331  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2332  **/
2333 static void read_dump(const char *fname, unsigned int kernel)
2334 {
2335         unsigned long size, pos = 0;
2336         void *file = grab_file(fname, &size);
2337         char *line;
2338
2339         if (!file)
2340                 /* No symbol versions, silently ignore */
2341                 return;
2342
2343         while ((line = get_next_line(&pos, file, size))) {
2344                 char *symname, *modname, *d, *export, *end;
2345                 unsigned int crc;
2346                 struct module *mod;
2347                 struct symbol *s;
2348
2349                 if (!(symname = strchr(line, '\t')))
2350                         goto fail;
2351                 *symname++ = '\0';
2352                 if (!(modname = strchr(symname, '\t')))
2353                         goto fail;
2354                 *modname++ = '\0';
2355                 if ((export = strchr(modname, '\t')) != NULL)
2356                         *export++ = '\0';
2357                 if (export && ((end = strchr(export, '\t')) != NULL))
2358                         *end = '\0';
2359                 crc = strtoul(line, &d, 16);
2360                 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2361                         goto fail;
2362                 mod = find_module(modname);
2363                 if (!mod) {
2364                         if (is_vmlinux(modname))
2365                                 have_vmlinux = 1;
2366                         mod = new_module(modname);
2367                         mod->skip = 1;
2368                 }
2369                 s = sym_add_exported(symname, mod, export_no(export));
2370                 s->kernel    = kernel;
2371                 s->preloaded = 1;
2372                 sym_update_crc(symname, mod, crc, export_no(export));
2373         }
2374         release_file(file, size);
2375         return;
2376 fail:
2377         release_file(file, size);
2378         fatal("parse error in symbol dump file\n");
2379 }
2380
2381 /* For normal builds always dump all symbols.
2382  * For external modules only dump symbols
2383  * that are not read from kernel Module.symvers.
2384  **/
2385 static int dump_sym(struct symbol *sym)
2386 {
2387         if (!external_module)
2388                 return 1;
2389         if (sym->vmlinux || sym->kernel)
2390                 return 0;
2391         return 1;
2392 }
2393
2394 static void write_dump(const char *fname)
2395 {
2396         struct buffer buf = { };
2397         struct symbol *symbol;
2398         int n;
2399
2400         for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2401                 symbol = symbolhash[n];
2402                 while (symbol) {
2403                         if (dump_sym(symbol))
2404                                 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2405                                         symbol->crc, symbol->name,
2406                                         symbol->module->name,
2407                                         export_str(symbol->export));
2408                         symbol = symbol->next;
2409                 }
2410         }
2411         write_if_changed(&buf, fname);
2412         free(buf.p);
2413 }
2414
2415 struct ext_sym_list {
2416         struct ext_sym_list *next;
2417         const char *file;
2418 };
2419
2420 int main(int argc, char **argv)
2421 {
2422         struct module *mod;
2423         struct buffer buf = { };
2424         char *kernel_read = NULL, *module_read = NULL;
2425         char *dump_write = NULL, *files_source = NULL;
2426         int opt;
2427         int err;
2428         struct ext_sym_list *extsym_iter;
2429         struct ext_sym_list *extsym_start = NULL;
2430
2431         while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2432                 switch (opt) {
2433                 case 'i':
2434                         kernel_read = optarg;
2435                         break;
2436                 case 'I':
2437                         module_read = optarg;
2438                         external_module = 1;
2439                         break;
2440                 case 'e':
2441                         external_module = 1;
2442                         extsym_iter =
2443                            NOFAIL(malloc(sizeof(*extsym_iter)));
2444                         extsym_iter->next = extsym_start;
2445                         extsym_iter->file = optarg;
2446                         extsym_start = extsym_iter;
2447                         break;
2448                 case 'm':
2449                         modversions = 1;
2450                         break;
2451                 case 'n':
2452                         ignore_missing_files = 1;
2453                         break;
2454                 case 'o':
2455                         dump_write = optarg;
2456                         break;
2457                 case 'a':
2458                         all_versions = 1;
2459                         break;
2460                 case 's':
2461                         vmlinux_section_warnings = 0;
2462                         break;
2463                 case 'S':
2464                         sec_mismatch_verbose = 0;
2465                         break;
2466                 case 'T':
2467                         files_source = optarg;
2468                         break;
2469                 case 'w':
2470                         warn_unresolved = 1;
2471                         break;
2472                 case 'E':
2473                         sec_mismatch_fatal = 1;
2474                         break;
2475                 default:
2476                         exit(1);
2477                 }
2478         }
2479
2480         if (kernel_read)
2481                 read_dump(kernel_read, 1);
2482         if (module_read)
2483                 read_dump(module_read, 0);
2484         while (extsym_start) {
2485                 read_dump(extsym_start->file, 0);
2486                 extsym_iter = extsym_start->next;
2487                 free(extsym_start);
2488                 extsym_start = extsym_iter;
2489         }
2490
2491         while (optind < argc)
2492                 read_symbols(argv[optind++]);
2493
2494         if (files_source)
2495                 read_symbols_from_files(files_source);
2496
2497         for (mod = modules; mod; mod = mod->next) {
2498                 if (mod->skip)
2499                         continue;
2500                 check_exports(mod);
2501         }
2502
2503         err = 0;
2504
2505         for (mod = modules; mod; mod = mod->next) {
2506                 char fname[PATH_MAX];
2507
2508                 if (mod->skip)
2509                         continue;
2510
2511                 buf.pos = 0;
2512
2513                 err |= check_modname_len(mod);
2514                 add_header(&buf, mod);
2515                 add_intree_flag(&buf, !external_module);
2516                 add_retpoline(&buf);
2517                 add_staging_flag(&buf, mod->name);
2518                 err |= add_versions(&buf, mod);
2519                 add_depends(&buf, mod, modules);
2520                 add_moddevtable(&buf, mod);
2521                 add_srcversion(&buf, mod);
2522
2523                 sprintf(fname, "%s.mod.c", mod->name);
2524                 write_if_changed(&buf, fname);
2525         }
2526         if (dump_write)
2527                 write_dump(dump_write);
2528         if (sec_mismatch_count) {
2529                 if (!sec_mismatch_verbose) {
2530                         warn("modpost: Found %d section mismatch(es).\n"
2531                              "To see full details build your kernel with:\n"
2532                              "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2533                              sec_mismatch_count);
2534                 }
2535                 if (sec_mismatch_fatal) {
2536                         fatal("modpost: Section mismatches detected.\n"
2537                               "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2538                 }
2539         }
2540         free(buf.p);
2541
2542         return err;
2543 }