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