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