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 #include <ctype.h> 15 #include "modpost.h" 16 #include "../../include/linux/license.h" 17 18 /* Are we using CONFIG_MODVERSIONS? */ 19 int modversions = 0; 20 /* Warn about undefined symbols? (do so if we have vmlinux) */ 21 int have_vmlinux = 0; 22 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ 23 static int all_versions = 0; 24 /* If we are modposting external module set to 1 */ 25 static int external_module = 0; 26 /* Warn about section mismatch in vmlinux if set to 1 */ 27 static int vmlinux_section_warnings = 1; 28 /* Only warn about unresolved symbols */ 29 static int warn_unresolved = 0; 30 /* How a symbol is exported */ 31 static int sec_mismatch_count = 0; 32 static int sec_mismatch_verbose = 1; 33 34 enum export { 35 export_plain, export_unused, export_gpl, 36 export_unused_gpl, export_gpl_future, export_unknown 37 }; 38 39 #define PRINTF __attribute__ ((format (printf, 1, 2))) 40 41 PRINTF void fatal(const char *fmt, ...) 42 { 43 va_list arglist; 44 45 fprintf(stderr, "FATAL: "); 46 47 va_start(arglist, fmt); 48 vfprintf(stderr, fmt, arglist); 49 va_end(arglist); 50 51 exit(1); 52 } 53 54 PRINTF void warn(const char *fmt, ...) 55 { 56 va_list arglist; 57 58 fprintf(stderr, "WARNING: "); 59 60 va_start(arglist, fmt); 61 vfprintf(stderr, fmt, arglist); 62 va_end(arglist); 63 } 64 65 PRINTF void merror(const char *fmt, ...) 66 { 67 va_list arglist; 68 69 fprintf(stderr, "ERROR: "); 70 71 va_start(arglist, fmt); 72 vfprintf(stderr, fmt, arglist); 73 va_end(arglist); 74 } 75 76 static int is_vmlinux(const char *modname) 77 { 78 const char *myname; 79 80 myname = strrchr(modname, '/'); 81 if (myname) 82 myname++; 83 else 84 myname = modname; 85 86 return (strcmp(myname, "vmlinux") == 0) || 87 (strcmp(myname, "vmlinux.o") == 0); 88 } 89 90 void *do_nofail(void *ptr, const char *expr) 91 { 92 if (!ptr) 93 fatal("modpost: Memory allocation failure: %s.\n", expr); 94 95 return ptr; 96 } 97 98 /* A list of all modules we processed */ 99 static struct module *modules; 100 101 static struct module *find_module(char *modname) 102 { 103 struct module *mod; 104 105 for (mod = modules; mod; mod = mod->next) 106 if (strcmp(mod->name, modname) == 0) 107 break; 108 return mod; 109 } 110 111 static struct module *new_module(char *modname) 112 { 113 struct module *mod; 114 char *p, *s; 115 116 mod = NOFAIL(malloc(sizeof(*mod))); 117 memset(mod, 0, sizeof(*mod)); 118 p = NOFAIL(strdup(modname)); 119 120 /* strip trailing .o */ 121 s = strrchr(p, '.'); 122 if (s != NULL) 123 if (strcmp(s, ".o") == 0) 124 *s = '\0'; 125 126 /* add to list */ 127 mod->name = p; 128 mod->gpl_compatible = -1; 129 mod->next = modules; 130 modules = mod; 131 132 return mod; 133 } 134 135 /* A hash of all exported symbols, 136 * struct symbol is also used for lists of unresolved symbols */ 137 138 #define SYMBOL_HASH_SIZE 1024 139 140 struct symbol { 141 struct symbol *next; 142 struct module *module; 143 unsigned int crc; 144 int crc_valid; 145 unsigned int weak:1; 146 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ 147 unsigned int kernel:1; /* 1 if symbol is from kernel 148 * (only for external modules) **/ 149 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */ 150 enum export export; /* Type of export */ 151 char name[0]; 152 }; 153 154 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 155 156 /* This is based on the hash agorithm from gdbm, via tdb */ 157 static inline unsigned int tdb_hash(const char *name) 158 { 159 unsigned value; /* Used to compute the hash value. */ 160 unsigned i; /* Used to cycle through random values. */ 161 162 /* Set the initial value from the key size. */ 163 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++) 164 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 165 166 return (1103515243 * value + 12345); 167 } 168 169 /** 170 * Allocate a new symbols for use in the hash of exported symbols or 171 * the list of unresolved symbols per module 172 **/ 173 static struct symbol *alloc_symbol(const char *name, unsigned int weak, 174 struct symbol *next) 175 { 176 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 177 178 memset(s, 0, sizeof(*s)); 179 strcpy(s->name, name); 180 s->weak = weak; 181 s->next = next; 182 return s; 183 } 184 185 /* For the hash of exported symbols */ 186 static struct symbol *new_symbol(const char *name, struct module *module, 187 enum export export) 188 { 189 unsigned int hash; 190 struct symbol *new; 191 192 hash = tdb_hash(name) % SYMBOL_HASH_SIZE; 193 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); 194 new->module = module; 195 new->export = export; 196 return new; 197 } 198 199 static struct symbol *find_symbol(const char *name) 200 { 201 struct symbol *s; 202 203 /* For our purposes, .foo matches foo. PPC64 needs this. */ 204 if (name[0] == '.') 205 name++; 206 207 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) { 208 if (strcmp(s->name, name) == 0) 209 return s; 210 } 211 return NULL; 212 } 213 214 static struct { 215 const char *str; 216 enum export export; 217 } export_list[] = { 218 { .str = "EXPORT_SYMBOL", .export = export_plain }, 219 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused }, 220 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl }, 221 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl }, 222 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future }, 223 { .str = "(unknown)", .export = export_unknown }, 224 }; 225 226 227 static const char *export_str(enum export ex) 228 { 229 return export_list[ex].str; 230 } 231 232 static enum export export_no(const char *s) 233 { 234 int i; 235 236 if (!s) 237 return export_unknown; 238 for (i = 0; export_list[i].export != export_unknown; i++) { 239 if (strcmp(export_list[i].str, s) == 0) 240 return export_list[i].export; 241 } 242 return export_unknown; 243 } 244 245 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec) 246 { 247 if (sec == elf->export_sec) 248 return export_plain; 249 else if (sec == elf->export_unused_sec) 250 return export_unused; 251 else if (sec == elf->export_gpl_sec) 252 return export_gpl; 253 else if (sec == elf->export_unused_gpl_sec) 254 return export_unused_gpl; 255 else if (sec == elf->export_gpl_future_sec) 256 return export_gpl_future; 257 else 258 return export_unknown; 259 } 260 261 /** 262 * Add an exported symbol - it may have already been added without a 263 * CRC, in this case just update the CRC 264 **/ 265 static struct symbol *sym_add_exported(const char *name, struct module *mod, 266 enum export export) 267 { 268 struct symbol *s = find_symbol(name); 269 270 if (!s) { 271 s = new_symbol(name, mod, export); 272 } else { 273 if (!s->preloaded) { 274 warn("%s: '%s' exported twice. Previous export " 275 "was in %s%s\n", mod->name, name, 276 s->module->name, 277 is_vmlinux(s->module->name) ?"":".ko"); 278 } else { 279 /* In case Modules.symvers was out of date */ 280 s->module = mod; 281 } 282 } 283 s->preloaded = 0; 284 s->vmlinux = is_vmlinux(mod->name); 285 s->kernel = 0; 286 s->export = export; 287 return s; 288 } 289 290 static void sym_update_crc(const char *name, struct module *mod, 291 unsigned int crc, enum export export) 292 { 293 struct symbol *s = find_symbol(name); 294 295 if (!s) 296 s = new_symbol(name, mod, export); 297 s->crc = crc; 298 s->crc_valid = 1; 299 } 300 301 void *grab_file(const char *filename, unsigned long *size) 302 { 303 struct stat st; 304 void *map; 305 int fd; 306 307 fd = open(filename, O_RDONLY); 308 if (fd < 0 || fstat(fd, &st) != 0) 309 return NULL; 310 311 *size = st.st_size; 312 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 313 close(fd); 314 315 if (map == MAP_FAILED) 316 return NULL; 317 return map; 318 } 319 320 /** 321 * Return a copy of the next line in a mmap'ed file. 322 * spaces in the beginning of the line is trimmed away. 323 * Return a pointer to a static buffer. 324 **/ 325 char *get_next_line(unsigned long *pos, void *file, unsigned long size) 326 { 327 static char line[4096]; 328 int skip = 1; 329 size_t len = 0; 330 signed char *p = (signed char *)file + *pos; 331 char *s = line; 332 333 for (; *pos < size ; (*pos)++) { 334 if (skip && isspace(*p)) { 335 p++; 336 continue; 337 } 338 skip = 0; 339 if (*p != '\n' && (*pos < size)) { 340 len++; 341 *s++ = *p++; 342 if (len > 4095) 343 break; /* Too long, stop */ 344 } else { 345 /* End of string */ 346 *s = '\0'; 347 return line; 348 } 349 } 350 /* End of buffer */ 351 return NULL; 352 } 353 354 void release_file(void *file, unsigned long size) 355 { 356 munmap(file, size); 357 } 358 359 static int parse_elf(struct elf_info *info, const char *filename) 360 { 361 unsigned int i; 362 Elf_Ehdr *hdr; 363 Elf_Shdr *sechdrs; 364 Elf_Sym *sym; 365 366 hdr = grab_file(filename, &info->size); 367 if (!hdr) { 368 perror(filename); 369 exit(1); 370 } 371 info->hdr = hdr; 372 if (info->size < sizeof(*hdr)) { 373 /* file too small, assume this is an empty .o file */ 374 return 0; 375 } 376 /* Is this a valid ELF file? */ 377 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) || 378 (hdr->e_ident[EI_MAG1] != ELFMAG1) || 379 (hdr->e_ident[EI_MAG2] != ELFMAG2) || 380 (hdr->e_ident[EI_MAG3] != ELFMAG3)) { 381 /* Not an ELF file - silently ignore it */ 382 return 0; 383 } 384 /* Fix endianness in ELF header */ 385 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 386 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 387 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 388 hdr->e_machine = TO_NATIVE(hdr->e_machine); 389 hdr->e_type = TO_NATIVE(hdr->e_type); 390 sechdrs = (void *)hdr + hdr->e_shoff; 391 info->sechdrs = sechdrs; 392 393 /* Check if file offset is correct */ 394 if (hdr->e_shoff > info->size) { 395 fatal("section header offset=%lu in file '%s' is bigger than " 396 "filesize=%lu\n", (unsigned long)hdr->e_shoff, 397 filename, info->size); 398 return 0; 399 } 400 401 /* Fix endianness in section headers */ 402 for (i = 0; i < hdr->e_shnum; i++) { 403 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 404 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 405 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 406 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 407 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 408 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info); 409 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); 410 } 411 /* Find symbol table. */ 412 for (i = 1; i < hdr->e_shnum; i++) { 413 const char *secstrings 414 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 415 const char *secname; 416 417 if (sechdrs[i].sh_offset > info->size) { 418 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > " 419 "sizeof(*hrd)=%zu\n", filename, 420 (unsigned long)sechdrs[i].sh_offset, 421 sizeof(*hdr)); 422 return 0; 423 } 424 secname = secstrings + sechdrs[i].sh_name; 425 if (strcmp(secname, ".modinfo") == 0) { 426 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 427 info->modinfo_len = sechdrs[i].sh_size; 428 } else if (strcmp(secname, "__ksymtab") == 0) 429 info->export_sec = i; 430 else if (strcmp(secname, "__ksymtab_unused") == 0) 431 info->export_unused_sec = i; 432 else if (strcmp(secname, "__ksymtab_gpl") == 0) 433 info->export_gpl_sec = i; 434 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0) 435 info->export_unused_gpl_sec = i; 436 else if (strcmp(secname, "__ksymtab_gpl_future") == 0) 437 info->export_gpl_future_sec = i; 438 439 if (sechdrs[i].sh_type != SHT_SYMTAB) 440 continue; 441 442 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; 443 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset 444 + sechdrs[i].sh_size; 445 info->strtab = (void *)hdr + 446 sechdrs[sechdrs[i].sh_link].sh_offset; 447 } 448 if (!info->symtab_start) 449 fatal("%s has no symtab?\n", filename); 450 451 /* Fix endianness in symbols */ 452 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 453 sym->st_shndx = TO_NATIVE(sym->st_shndx); 454 sym->st_name = TO_NATIVE(sym->st_name); 455 sym->st_value = TO_NATIVE(sym->st_value); 456 sym->st_size = TO_NATIVE(sym->st_size); 457 } 458 return 1; 459 } 460 461 static void parse_elf_finish(struct elf_info *info) 462 { 463 release_file(info->hdr, info->size); 464 } 465 466 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_" 467 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_" 468 469 static void handle_modversions(struct module *mod, struct elf_info *info, 470 Elf_Sym *sym, const char *symname) 471 { 472 unsigned int crc; 473 enum export export = export_from_sec(info, sym->st_shndx); 474 475 switch (sym->st_shndx) { 476 case SHN_COMMON: 477 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 478 break; 479 case SHN_ABS: 480 /* CRC'd symbol */ 481 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) { 482 crc = (unsigned int) sym->st_value; 483 sym_update_crc(symname + strlen(CRC_PFX), mod, crc, 484 export); 485 } 486 break; 487 case SHN_UNDEF: 488 /* undefined symbol */ 489 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 490 ELF_ST_BIND(sym->st_info) != STB_WEAK) 491 break; 492 /* ignore global offset table */ 493 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 494 break; 495 /* ignore __this_module, it will be resolved shortly */ 496 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0) 497 break; 498 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ 499 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) 500 /* add compatibility with older glibc */ 501 #ifndef STT_SPARC_REGISTER 502 #define STT_SPARC_REGISTER STT_REGISTER 503 #endif 504 if (info->hdr->e_machine == EM_SPARC || 505 info->hdr->e_machine == EM_SPARCV9) { 506 /* Ignore register directives. */ 507 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 508 break; 509 if (symname[0] == '.') { 510 char *munged = strdup(symname); 511 munged[0] = '_'; 512 munged[1] = toupper(munged[1]); 513 symname = munged; 514 } 515 } 516 #endif 517 518 if (memcmp(symname, MODULE_SYMBOL_PREFIX, 519 strlen(MODULE_SYMBOL_PREFIX)) == 0) { 520 mod->unres = 521 alloc_symbol(symname + 522 strlen(MODULE_SYMBOL_PREFIX), 523 ELF_ST_BIND(sym->st_info) == STB_WEAK, 524 mod->unres); 525 } 526 break; 527 default: 528 /* All exported symbols */ 529 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) { 530 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod, 531 export); 532 } 533 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0) 534 mod->has_init = 1; 535 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0) 536 mod->has_cleanup = 1; 537 break; 538 } 539 } 540 541 /** 542 * Parse tag=value strings from .modinfo section 543 **/ 544 static char *next_string(char *string, unsigned long *secsize) 545 { 546 /* Skip non-zero chars */ 547 while (string[0]) { 548 string++; 549 if ((*secsize)-- <= 1) 550 return NULL; 551 } 552 553 /* Skip any zero padding. */ 554 while (!string[0]) { 555 string++; 556 if ((*secsize)-- <= 1) 557 return NULL; 558 } 559 return string; 560 } 561 562 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len, 563 const char *tag, char *info) 564 { 565 char *p; 566 unsigned int taglen = strlen(tag); 567 unsigned long size = modinfo_len; 568 569 if (info) { 570 size -= info - (char *)modinfo; 571 modinfo = next_string(info, &size); 572 } 573 574 for (p = modinfo; p; p = next_string(p, &size)) { 575 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 576 return p + taglen + 1; 577 } 578 return NULL; 579 } 580 581 static char *get_modinfo(void *modinfo, unsigned long modinfo_len, 582 const char *tag) 583 584 { 585 return get_next_modinfo(modinfo, modinfo_len, tag, NULL); 586 } 587 588 /** 589 * Test if string s ends in string sub 590 * return 0 if match 591 **/ 592 static int strrcmp(const char *s, const char *sub) 593 { 594 int slen, sublen; 595 596 if (!s || !sub) 597 return 1; 598 599 slen = strlen(s); 600 sublen = strlen(sub); 601 602 if ((slen == 0) || (sublen == 0)) 603 return 1; 604 605 if (sublen > slen) 606 return 1; 607 608 return memcmp(s + slen - sublen, sub, sublen); 609 } 610 611 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) 612 { 613 if (sym) 614 return elf->strtab + sym->st_name; 615 else 616 return "(unknown)"; 617 } 618 619 static const char *sec_name(struct elf_info *elf, int shndx) 620 { 621 Elf_Shdr *sechdrs = elf->sechdrs; 622 return (void *)elf->hdr + 623 elf->sechdrs[elf->hdr->e_shstrndx].sh_offset + 624 sechdrs[shndx].sh_name; 625 } 626 627 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr) 628 { 629 return (void *)elf->hdr + 630 elf->sechdrs[elf->hdr->e_shstrndx].sh_offset + 631 sechdr->sh_name; 632 } 633 634 /* if sym is empty or point to a string 635 * like ".[0-9]+" then return 1. 636 * This is the optional prefix added by ld to some sections 637 */ 638 static int number_prefix(const char *sym) 639 { 640 if (*sym++ == '\0') 641 return 1; 642 if (*sym != '.') 643 return 0; 644 do { 645 char c = *sym++; 646 if (c < '0' || c > '9') 647 return 0; 648 } while (*sym); 649 return 1; 650 } 651 652 /* The pattern is an array of simple patterns. 653 * "foo" will match an exact string equal to "foo" 654 * "*foo" will match a string that ends with "foo" 655 * "foo*" will match a string that begins with "foo" 656 * "foo$" will match a string equal to "foo" or "foo.1" 657 * where the '1' can be any number including several digits. 658 * The $ syntax is for sections where ld append a dot number 659 * to make section name unique. 660 */ 661 int match(const char *sym, const char * const pat[]) 662 { 663 const char *p; 664 while (*pat) { 665 p = *pat++; 666 const char *endp = p + strlen(p) - 1; 667 668 /* "*foo" */ 669 if (*p == '*') { 670 if (strrcmp(sym, p + 1) == 0) 671 return 1; 672 } 673 /* "foo*" */ 674 else if (*endp == '*') { 675 if (strncmp(sym, p, strlen(p) - 1) == 0) 676 return 1; 677 } 678 /* "foo$" */ 679 else if (*endp == '$') { 680 if (strncmp(sym, p, strlen(p) - 1) == 0) { 681 if (number_prefix(sym + strlen(p) - 1)) 682 return 1; 683 } 684 } 685 /* no wildcards */ 686 else { 687 if (strcmp(p, sym) == 0) 688 return 1; 689 } 690 } 691 /* no match */ 692 return 0; 693 } 694 695 /* sections that we do not want to do full section mismatch check on */ 696 static const char *section_white_list[] = 697 { ".debug*", ".stab*", ".note*", ".got*", ".toc*", NULL }; 698 699 /* 700 * Is this section one we do not want to check? 701 * This is often debug sections. 702 * If we are going to check this section then 703 * test if section name ends with a dot and a number. 704 * This is used to find sections where the linker have 705 * appended a dot-number to make the name unique. 706 * The cause of this is often a section specified in assembler 707 * without "ax" / "aw" and the same section used in .c 708 * code where gcc add these. 709 */ 710 static int check_section(const char *modname, const char *sec) 711 { 712 const char *e = sec + strlen(sec) - 1; 713 if (match(sec, section_white_list)) 714 return 1; 715 716 if (*e && isdigit(*e)) { 717 /* consume all digits */ 718 while (*e && e != sec && isdigit(*e)) 719 e--; 720 if (*e == '.') { 721 warn("%s (%s): unexpected section name.\n" 722 "The (.[number]+) following section name are " 723 "ld generated and not expected.\n" 724 "Did you forget to use \"ax\"/\"aw\" " 725 "in a .S file?\n" 726 "Note that for example <linux/init.h> contains\n" 727 "section definitions for use in .S files.\n\n", 728 modname, sec); 729 } 730 } 731 return 0; 732 } 733 734 735 736 #define ALL_INIT_DATA_SECTIONS \ 737 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$" 738 #define ALL_EXIT_DATA_SECTIONS \ 739 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$" 740 741 #define ALL_INIT_TEXT_SECTIONS \ 742 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$" 743 #define ALL_EXIT_TEXT_SECTIONS \ 744 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$" 745 746 #define ALL_INIT_SECTIONS ALL_INIT_DATA_SECTIONS, ALL_INIT_TEXT_SECTIONS 747 #define ALL_EXIT_SECTIONS ALL_EXIT_DATA_SECTIONS, ALL_EXIT_TEXT_SECTIONS 748 749 #define DATA_SECTIONS ".data$", ".data.rel$" 750 #define TEXT_SECTIONS ".text$" 751 752 #define INIT_SECTIONS ".init.data$", ".init.text$" 753 #define DEV_INIT_SECTIONS ".devinit.data$", ".devinit.text$" 754 #define CPU_INIT_SECTIONS ".cpuinit.data$", ".cpuinit.text$" 755 #define MEM_INIT_SECTIONS ".meminit.data$", ".meminit.text$" 756 757 #define EXIT_SECTIONS ".exit.data$", ".exit.text$" 758 #define DEV_EXIT_SECTIONS ".devexit.data$", ".devexit.text$" 759 #define CPU_EXIT_SECTIONS ".cpuexit.data$", ".cpuexit.text$" 760 #define MEM_EXIT_SECTIONS ".memexit.data$", ".memexit.text$" 761 762 /* init data sections */ 763 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL }; 764 765 /* all init sections */ 766 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL }; 767 768 /* All init and exit sections (code + data) */ 769 static const char *init_exit_sections[] = 770 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }; 771 772 /* data section */ 773 static const char *data_sections[] = { DATA_SECTIONS, NULL }; 774 775 /* sections that may refer to an init/exit section with no warning */ 776 static const char *initref_sections[] = 777 { 778 ".text.init.refok*", 779 ".exit.text.refok*", 780 ".data.init.refok*", 781 NULL 782 }; 783 784 785 /* symbols in .data that may refer to init/exit sections */ 786 static const char *symbol_white_list[] = 787 { 788 "*driver", 789 "*_template", /* scsi uses *_template a lot */ 790 "*_timer", /* arm uses ops structures named _timer a lot */ 791 "*_sht", /* scsi also used *_sht to some extent */ 792 "*_ops", 793 "*_probe", 794 "*_probe_one", 795 "*_console", 796 NULL 797 }; 798 799 static const char *head_sections[] = { ".head.text*", NULL }; 800 static const char *linker_symbols[] = 801 { "__init_begin", "_sinittext", "_einittext", NULL }; 802 803 enum mismatch { 804 NO_MISMATCH, 805 TEXT_TO_INIT, 806 DATA_TO_INIT, 807 TEXT_TO_EXIT, 808 DATA_TO_EXIT, 809 XXXINIT_TO_INIT, 810 XXXEXIT_TO_EXIT, 811 INIT_TO_EXIT, 812 EXIT_TO_INIT, 813 EXPORT_TO_INIT_EXIT, 814 }; 815 816 struct sectioncheck { 817 const char *fromsec[20]; 818 const char *tosec[20]; 819 enum mismatch mismatch; 820 }; 821 822 const struct sectioncheck sectioncheck[] = { 823 /* Do not reference init/exit code/data from 824 * normal code and data 825 */ 826 { 827 .fromsec = { TEXT_SECTIONS, NULL }, 828 .tosec = { ALL_INIT_SECTIONS, NULL }, 829 .mismatch = TEXT_TO_INIT, 830 }, 831 { 832 .fromsec = { DATA_SECTIONS, NULL }, 833 .tosec = { ALL_INIT_SECTIONS, NULL }, 834 .mismatch = DATA_TO_INIT, 835 }, 836 { 837 .fromsec = { TEXT_SECTIONS, NULL }, 838 .tosec = { ALL_EXIT_SECTIONS, NULL }, 839 .mismatch = TEXT_TO_EXIT, 840 }, 841 { 842 .fromsec = { DATA_SECTIONS, NULL }, 843 .tosec = { ALL_EXIT_SECTIONS, NULL }, 844 .mismatch = DATA_TO_EXIT, 845 }, 846 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */ 847 { 848 .fromsec = { DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, MEM_INIT_SECTIONS, NULL }, 849 .tosec = { INIT_SECTIONS, NULL }, 850 .mismatch = XXXINIT_TO_INIT, 851 }, 852 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */ 853 { 854 .fromsec = { DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, MEM_EXIT_SECTIONS, NULL }, 855 .tosec = { EXIT_SECTIONS, NULL }, 856 .mismatch = XXXEXIT_TO_EXIT, 857 }, 858 /* Do not use exit code/data from init code */ 859 { 860 .fromsec = { ALL_INIT_SECTIONS, NULL }, 861 .tosec = { ALL_EXIT_SECTIONS, NULL }, 862 .mismatch = INIT_TO_EXIT, 863 }, 864 /* Do not use init code/data from exit code */ 865 { 866 .fromsec = { ALL_EXIT_SECTIONS, NULL }, 867 .tosec = { ALL_INIT_SECTIONS, NULL }, 868 .mismatch = EXIT_TO_INIT, 869 }, 870 /* Do not export init/exit functions or data */ 871 { 872 .fromsec = { "__ksymtab*", NULL }, 873 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, 874 .mismatch = EXPORT_TO_INIT_EXIT 875 } 876 }; 877 878 static int section_mismatch(const char *fromsec, const char *tosec) 879 { 880 int i; 881 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck); 882 const struct sectioncheck *check = §ioncheck[0]; 883 884 for (i = 0; i < elems; i++) { 885 if (match(fromsec, check->fromsec) && 886 match(tosec, check->tosec)) 887 return check->mismatch; 888 check++; 889 } 890 return NO_MISMATCH; 891 } 892 893 /** 894 * Whitelist to allow certain references to pass with no warning. 895 * 896 * Pattern 0: 897 * Do not warn if funtion/data are marked with __init_refok/__initdata_refok. 898 * The pattern is identified by: 899 * fromsec = .text.init.refok* | .data.init.refok* 900 * 901 * Pattern 1: 902 * If a module parameter is declared __initdata and permissions=0 903 * then this is legal despite the warning generated. 904 * We cannot see value of permissions here, so just ignore 905 * this pattern. 906 * The pattern is identified by: 907 * tosec = .init.data 908 * fromsec = .data* 909 * atsym =__param* 910 * 911 * Pattern 2: 912 * Many drivers utilise a *driver container with references to 913 * add, remove, probe functions etc. 914 * These functions may often be marked __init and we do not want to 915 * warn here. 916 * the pattern is identified by: 917 * tosec = init or exit section 918 * fromsec = data section 919 * atsym = *driver, *_template, *_sht, *_ops, *_probe, 920 * *probe_one, *_console, *_timer 921 * 922 * Pattern 3: 923 * Whitelist all refereces from .text.head to .init.data 924 * Whitelist all refereces from .text.head to .init.text 925 * 926 * Pattern 4: 927 * Some symbols belong to init section but still it is ok to reference 928 * these from non-init sections as these symbols don't have any memory 929 * allocated for them and symbol address and value are same. So even 930 * if init section is freed, its ok to reference those symbols. 931 * For ex. symbols marking the init section boundaries. 932 * This pattern is identified by 933 * refsymname = __init_begin, _sinittext, _einittext 934 * 935 **/ 936 static int secref_whitelist(const char *fromsec, const char *fromsym, 937 const char *tosec, const char *tosym) 938 { 939 /* Check for pattern 0 */ 940 if (match(fromsec, initref_sections)) 941 return 0; 942 943 /* Check for pattern 1 */ 944 if (match(tosec, init_data_sections) && 945 match(fromsec, data_sections) && 946 (strncmp(fromsym, "__param", strlen("__param")) == 0)) 947 return 0; 948 949 /* Check for pattern 2 */ 950 if (match(tosec, init_exit_sections) && 951 match(fromsec, data_sections) && 952 match(fromsym, symbol_white_list)) 953 return 0; 954 955 /* Check for pattern 3 */ 956 if (match(fromsec, head_sections) && 957 match(tosec, init_sections)) 958 return 0; 959 960 /* Check for pattern 4 */ 961 if (match(tosym, linker_symbols)) 962 return 0; 963 964 return 1; 965 } 966 967 /** 968 * Find symbol based on relocation record info. 969 * In some cases the symbol supplied is a valid symbol so 970 * return refsym. If st_name != 0 we assume this is a valid symbol. 971 * In other cases the symbol needs to be looked up in the symbol table 972 * based on section and address. 973 * **/ 974 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, 975 Elf_Sym *relsym) 976 { 977 Elf_Sym *sym; 978 Elf_Sym *near = NULL; 979 Elf64_Sword distance = 20; 980 Elf64_Sword d; 981 982 if (relsym->st_name != 0) 983 return relsym; 984 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 985 if (sym->st_shndx != relsym->st_shndx) 986 continue; 987 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) 988 continue; 989 if (sym->st_value == addr) 990 return sym; 991 /* Find a symbol nearby - addr are maybe negative */ 992 d = sym->st_value - addr; 993 if (d < 0) 994 d = addr - sym->st_value; 995 if (d < distance) { 996 distance = d; 997 near = sym; 998 } 999 } 1000 /* We need a close match */ 1001 if (distance < 20) 1002 return near; 1003 else 1004 return NULL; 1005 } 1006 1007 static inline int is_arm_mapping_symbol(const char *str) 1008 { 1009 return str[0] == '$' && strchr("atd", str[1]) 1010 && (str[2] == '\0' || str[2] == '.'); 1011 } 1012 1013 /* 1014 * If there's no name there, ignore it; likewise, ignore it if it's 1015 * one of the magic symbols emitted used by current ARM tools. 1016 * 1017 * Otherwise if find_symbols_between() returns those symbols, they'll 1018 * fail the whitelist tests and cause lots of false alarms ... fixable 1019 * only by merging __exit and __init sections into __text, bloating 1020 * the kernel (which is especially evil on embedded platforms). 1021 */ 1022 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) 1023 { 1024 const char *name = elf->strtab + sym->st_name; 1025 1026 if (!name || !strlen(name)) 1027 return 0; 1028 return !is_arm_mapping_symbol(name); 1029 } 1030 1031 /* 1032 * Find symbols before or equal addr and after addr - in the section sec. 1033 * If we find two symbols with equal offset prefer one with a valid name. 1034 * The ELF format may have a better way to detect what type of symbol 1035 * it is, but this works for now. 1036 **/ 1037 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, 1038 const char *sec) 1039 { 1040 Elf_Sym *sym; 1041 Elf_Sym *near = NULL; 1042 Elf_Addr distance = ~0; 1043 1044 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1045 const char *symsec; 1046 1047 if (sym->st_shndx >= SHN_LORESERVE) 1048 continue; 1049 symsec = sec_name(elf, sym->st_shndx); 1050 if (strcmp(symsec, sec) != 0) 1051 continue; 1052 if (!is_valid_name(elf, sym)) 1053 continue; 1054 if (sym->st_value <= addr) { 1055 if ((addr - sym->st_value) < distance) { 1056 distance = addr - sym->st_value; 1057 near = sym; 1058 } else if ((addr - sym->st_value) == distance) { 1059 near = sym; 1060 } 1061 } 1062 } 1063 return near; 1064 } 1065 1066 /* 1067 * Convert a section name to the function/data attribute 1068 * .init.text => __init 1069 * .cpuinit.data => __cpudata 1070 * .memexitconst => __memconst 1071 * etc. 1072 */ 1073 static char *sec2annotation(const char *s) 1074 { 1075 if (match(s, init_exit_sections)) { 1076 char *p = malloc(20); 1077 char *r = p; 1078 1079 *p++ = '_'; 1080 *p++ = '_'; 1081 if (*s == '.') 1082 s++; 1083 while (*s && *s != '.') 1084 *p++ = *s++; 1085 *p = '\0'; 1086 if (*s == '.') 1087 s++; 1088 if (strstr(s, "rodata") != NULL) 1089 strcat(p, "const "); 1090 else if (strstr(s, "data") != NULL) 1091 strcat(p, "data "); 1092 else 1093 strcat(p, " "); 1094 return r; /* we leak her but we do not care */ 1095 } else { 1096 return ""; 1097 } 1098 } 1099 1100 static int is_function(Elf_Sym *sym) 1101 { 1102 if (sym) 1103 return ELF_ST_TYPE(sym->st_info) == STT_FUNC; 1104 else 1105 return -1; 1106 } 1107 1108 /* 1109 * Print a warning about a section mismatch. 1110 * Try to find symbols near it so user can find it. 1111 * Check whitelist before warning - it may be a false positive. 1112 */ 1113 static void report_sec_mismatch(const char *modname, enum mismatch mismatch, 1114 const char *fromsec, 1115 unsigned long long fromaddr, 1116 const char *fromsym, 1117 int from_is_func, 1118 const char *tosec, const char *tosym, 1119 int to_is_func) 1120 { 1121 const char *from, *from_p; 1122 const char *to, *to_p; 1123 1124 switch (from_is_func) { 1125 case 0: from = "variable"; from_p = ""; break; 1126 case 1: from = "function"; from_p = "()"; break; 1127 default: from = "(unknown reference)"; from_p = ""; break; 1128 } 1129 switch (to_is_func) { 1130 case 0: to = "variable"; to_p = ""; break; 1131 case 1: to = "function"; to_p = "()"; break; 1132 default: to = "(unknown reference)"; to_p = ""; break; 1133 } 1134 1135 sec_mismatch_count++; 1136 if (!sec_mismatch_verbose) 1137 return; 1138 1139 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " 1140 "to the %s %s:%s%s\n", 1141 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, 1142 tosym, to_p); 1143 1144 switch (mismatch) { 1145 case TEXT_TO_INIT: 1146 fprintf(stderr, 1147 "The function %s%s() references\n" 1148 "the %s %s%s%s.\n" 1149 "This is often because %s lacks a %s\n" 1150 "annotation or the annotation of %s is wrong.\n", 1151 sec2annotation(fromsec), fromsym, 1152 to, sec2annotation(tosec), tosym, to_p, 1153 fromsym, sec2annotation(tosec), tosym); 1154 break; 1155 case DATA_TO_INIT: { 1156 const char **s = symbol_white_list; 1157 fprintf(stderr, 1158 "The variable %s references\n" 1159 "the %s %s%s%s\n" 1160 "If the reference is valid then annotate the\n" 1161 "variable with __init* (see linux/init.h) " 1162 "or name the variable:\n", 1163 fromsym, to, sec2annotation(tosec), tosym, to_p); 1164 while (*s) 1165 fprintf(stderr, "%s, ", *s++); 1166 fprintf(stderr, "\n"); 1167 break; 1168 } 1169 case TEXT_TO_EXIT: 1170 fprintf(stderr, 1171 "The function %s() references a %s in an exit section.\n" 1172 "Often the %s %s%s has valid usage outside the exit section\n" 1173 "and the fix is to remove the %sannotation of %s.\n", 1174 fromsym, to, to, tosym, to_p, sec2annotation(tosec), tosym); 1175 break; 1176 case DATA_TO_EXIT: { 1177 const char **s = symbol_white_list; 1178 fprintf(stderr, 1179 "The variable %s references\n" 1180 "the %s %s%s%s\n" 1181 "If the reference is valid then annotate the\n" 1182 "variable with __exit* (see linux/init.h) or " 1183 "name the variable:\n", 1184 fromsym, to, sec2annotation(tosec), tosym, to_p); 1185 while (*s) 1186 fprintf(stderr, "%s, ", *s++); 1187 fprintf(stderr, "\n"); 1188 break; 1189 } 1190 case XXXINIT_TO_INIT: 1191 case XXXEXIT_TO_EXIT: 1192 fprintf(stderr, 1193 "The %s %s%s%s references\n" 1194 "a %s %s%s%s.\n" 1195 "If %s is only used by %s then\n" 1196 "annotate %s with a matching annotation.\n", 1197 from, sec2annotation(fromsec), fromsym, from_p, 1198 to, sec2annotation(tosec), tosym, to_p, 1199 fromsym, tosym, fromsym); 1200 break; 1201 case INIT_TO_EXIT: 1202 fprintf(stderr, 1203 "The %s %s%s%s references\n" 1204 "a %s %s%s%s.\n" 1205 "This is often seen when error handling " 1206 "in the init function\n" 1207 "uses functionality in the exit path.\n" 1208 "The fix is often to remove the %sannotation of\n" 1209 "%s%s so it may be used outside an exit section.\n", 1210 from, sec2annotation(fromsec), fromsym, from_p, 1211 to, sec2annotation(tosec), tosym, to_p, 1212 sec2annotation(tosec), tosym, to_p); 1213 break; 1214 case EXIT_TO_INIT: 1215 fprintf(stderr, 1216 "The %s %s%s%s references\n" 1217 "a %s %s%s%s.\n" 1218 "This is often seen when error handling " 1219 "in the exit function\n" 1220 "uses functionality in the init path.\n" 1221 "The fix is often to remove the %sannotation of\n" 1222 "%s%s so it may be used outside an init section.\n", 1223 from, sec2annotation(fromsec), fromsym, from_p, 1224 to, sec2annotation(tosec), tosym, to_p, 1225 sec2annotation(tosec), tosym, to_p); 1226 break; 1227 case EXPORT_TO_INIT_EXIT: 1228 fprintf(stderr, 1229 "The symbol %s is exported and annotated %s\n" 1230 "Fix this by removing the %sannotation of %s " 1231 "or drop the export.\n", 1232 tosym, sec2annotation(tosec), sec2annotation(tosec), tosym); 1233 case NO_MISMATCH: 1234 /* To get warnings on missing members */ 1235 break; 1236 } 1237 fprintf(stderr, "\n"); 1238 } 1239 1240 static void check_section_mismatch(const char *modname, struct elf_info *elf, 1241 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1242 { 1243 const char *tosec; 1244 enum mismatch mismatch; 1245 1246 tosec = sec_name(elf, sym->st_shndx); 1247 mismatch = section_mismatch(fromsec, tosec); 1248 if (mismatch != NO_MISMATCH) { 1249 Elf_Sym *to; 1250 Elf_Sym *from; 1251 const char *tosym; 1252 const char *fromsym; 1253 1254 from = find_elf_symbol2(elf, r->r_offset, fromsec); 1255 fromsym = sym_name(elf, from); 1256 to = find_elf_symbol(elf, r->r_addend, sym); 1257 tosym = sym_name(elf, to); 1258 1259 /* check whitelist - we may ignore it */ 1260 if (secref_whitelist(fromsec, fromsym, tosec, tosym)) { 1261 report_sec_mismatch(modname, mismatch, 1262 fromsec, r->r_offset, fromsym, 1263 is_function(from), tosec, tosym, 1264 is_function(to)); 1265 } 1266 } 1267 } 1268 1269 static unsigned int *reloc_location(struct elf_info *elf, 1270 Elf_Shdr *sechdr, Elf_Rela *r) 1271 { 1272 Elf_Shdr *sechdrs = elf->sechdrs; 1273 int section = sechdr->sh_info; 1274 1275 return (void *)elf->hdr + sechdrs[section].sh_offset + 1276 (r->r_offset - sechdrs[section].sh_addr); 1277 } 1278 1279 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1280 { 1281 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1282 unsigned int *location = reloc_location(elf, sechdr, r); 1283 1284 switch (r_typ) { 1285 case R_386_32: 1286 r->r_addend = TO_NATIVE(*location); 1287 break; 1288 case R_386_PC32: 1289 r->r_addend = TO_NATIVE(*location) + 4; 1290 /* For CONFIG_RELOCATABLE=y */ 1291 if (elf->hdr->e_type == ET_EXEC) 1292 r->r_addend += r->r_offset; 1293 break; 1294 } 1295 return 0; 1296 } 1297 1298 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1299 { 1300 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1301 1302 switch (r_typ) { 1303 case R_ARM_ABS32: 1304 /* From ARM ABI: (S + A) | T */ 1305 r->r_addend = (int)(long) 1306 (elf->symtab_start + ELF_R_SYM(r->r_info)); 1307 break; 1308 case R_ARM_PC24: 1309 /* From ARM ABI: ((S + A) | T) - P */ 1310 r->r_addend = (int)(long)(elf->hdr + 1311 sechdr->sh_offset + 1312 (r->r_offset - sechdr->sh_addr)); 1313 break; 1314 default: 1315 return 1; 1316 } 1317 return 0; 1318 } 1319 1320 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1321 { 1322 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1323 unsigned int *location = reloc_location(elf, sechdr, r); 1324 unsigned int inst; 1325 1326 if (r_typ == R_MIPS_HI16) 1327 return 1; /* skip this */ 1328 inst = TO_NATIVE(*location); 1329 switch (r_typ) { 1330 case R_MIPS_LO16: 1331 r->r_addend = inst & 0xffff; 1332 break; 1333 case R_MIPS_26: 1334 r->r_addend = (inst & 0x03ffffff) << 2; 1335 break; 1336 case R_MIPS_32: 1337 r->r_addend = inst; 1338 break; 1339 } 1340 return 0; 1341 } 1342 1343 static void section_rela(const char *modname, struct elf_info *elf, 1344 Elf_Shdr *sechdr) 1345 { 1346 Elf_Sym *sym; 1347 Elf_Rela *rela; 1348 Elf_Rela r; 1349 unsigned int r_sym; 1350 const char *fromsec; 1351 1352 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; 1353 Elf_Rela *stop = (void *)start + sechdr->sh_size; 1354 1355 fromsec = sech_name(elf, sechdr); 1356 fromsec += strlen(".rela"); 1357 /* if from section (name) is know good then skip it */ 1358 if (check_section(modname, fromsec)) 1359 return; 1360 1361 for (rela = start; rela < stop; rela++) { 1362 r.r_offset = TO_NATIVE(rela->r_offset); 1363 #if KERNEL_ELFCLASS == ELFCLASS64 1364 if (elf->hdr->e_machine == EM_MIPS) { 1365 unsigned int r_typ; 1366 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 1367 r_sym = TO_NATIVE(r_sym); 1368 r_typ = ELF64_MIPS_R_TYPE(rela->r_info); 1369 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1370 } else { 1371 r.r_info = TO_NATIVE(rela->r_info); 1372 r_sym = ELF_R_SYM(r.r_info); 1373 } 1374 #else 1375 r.r_info = TO_NATIVE(rela->r_info); 1376 r_sym = ELF_R_SYM(r.r_info); 1377 #endif 1378 r.r_addend = TO_NATIVE(rela->r_addend); 1379 sym = elf->symtab_start + r_sym; 1380 /* Skip special sections */ 1381 if (sym->st_shndx >= SHN_LORESERVE) 1382 continue; 1383 check_section_mismatch(modname, elf, &r, sym, fromsec); 1384 } 1385 } 1386 1387 static void section_rel(const char *modname, struct elf_info *elf, 1388 Elf_Shdr *sechdr) 1389 { 1390 Elf_Sym *sym; 1391 Elf_Rel *rel; 1392 Elf_Rela r; 1393 unsigned int r_sym; 1394 const char *fromsec; 1395 1396 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; 1397 Elf_Rel *stop = (void *)start + sechdr->sh_size; 1398 1399 fromsec = sech_name(elf, sechdr); 1400 fromsec += strlen(".rel"); 1401 /* if from section (name) is know good then skip it */ 1402 if (check_section(modname, fromsec)) 1403 return; 1404 1405 for (rel = start; rel < stop; rel++) { 1406 r.r_offset = TO_NATIVE(rel->r_offset); 1407 #if KERNEL_ELFCLASS == ELFCLASS64 1408 if (elf->hdr->e_machine == EM_MIPS) { 1409 unsigned int r_typ; 1410 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 1411 r_sym = TO_NATIVE(r_sym); 1412 r_typ = ELF64_MIPS_R_TYPE(rel->r_info); 1413 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1414 } else { 1415 r.r_info = TO_NATIVE(rel->r_info); 1416 r_sym = ELF_R_SYM(r.r_info); 1417 } 1418 #else 1419 r.r_info = TO_NATIVE(rel->r_info); 1420 r_sym = ELF_R_SYM(r.r_info); 1421 #endif 1422 r.r_addend = 0; 1423 switch (elf->hdr->e_machine) { 1424 case EM_386: 1425 if (addend_386_rel(elf, sechdr, &r)) 1426 continue; 1427 break; 1428 case EM_ARM: 1429 if (addend_arm_rel(elf, sechdr, &r)) 1430 continue; 1431 break; 1432 case EM_MIPS: 1433 if (addend_mips_rel(elf, sechdr, &r)) 1434 continue; 1435 break; 1436 } 1437 sym = elf->symtab_start + r_sym; 1438 /* Skip special sections */ 1439 if (sym->st_shndx >= SHN_LORESERVE) 1440 continue; 1441 check_section_mismatch(modname, elf, &r, sym, fromsec); 1442 } 1443 } 1444 1445 /** 1446 * A module includes a number of sections that are discarded 1447 * either when loaded or when used as built-in. 1448 * For loaded modules all functions marked __init and all data 1449 * marked __initdata will be discarded when the module has been intialized. 1450 * Likewise for modules used built-in the sections marked __exit 1451 * are discarded because __exit marked function are supposed to be called 1452 * only when a moduel is unloaded which never happes for built-in modules. 1453 * The check_sec_ref() function traverses all relocation records 1454 * to find all references to a section that reference a section that will 1455 * be discarded and warns about it. 1456 **/ 1457 static void check_sec_ref(struct module *mod, const char *modname, 1458 struct elf_info *elf) 1459 { 1460 int i; 1461 Elf_Shdr *sechdrs = elf->sechdrs; 1462 1463 /* Walk through all sections */ 1464 for (i = 0; i < elf->hdr->e_shnum; i++) { 1465 /* We want to process only relocation sections and not .init */ 1466 if (sechdrs[i].sh_type == SHT_RELA) 1467 section_rela(modname, elf, &elf->sechdrs[i]); 1468 else if (sechdrs[i].sh_type == SHT_REL) 1469 section_rel(modname, elf, &elf->sechdrs[i]); 1470 } 1471 } 1472 1473 static void read_symbols(char *modname) 1474 { 1475 const char *symname; 1476 char *version; 1477 char *license; 1478 struct module *mod; 1479 struct elf_info info = { }; 1480 Elf_Sym *sym; 1481 1482 if (!parse_elf(&info, modname)) 1483 return; 1484 1485 mod = new_module(modname); 1486 1487 /* When there's no vmlinux, don't print warnings about 1488 * unresolved symbols (since there'll be too many ;) */ 1489 if (is_vmlinux(modname)) { 1490 have_vmlinux = 1; 1491 mod->skip = 1; 1492 } 1493 1494 license = get_modinfo(info.modinfo, info.modinfo_len, "license"); 1495 while (license) { 1496 if (license_is_gpl_compatible(license)) 1497 mod->gpl_compatible = 1; 1498 else { 1499 mod->gpl_compatible = 0; 1500 break; 1501 } 1502 license = get_next_modinfo(info.modinfo, info.modinfo_len, 1503 "license", license); 1504 } 1505 1506 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 1507 symname = info.strtab + sym->st_name; 1508 1509 handle_modversions(mod, &info, sym, symname); 1510 handle_moddevtable(mod, &info, sym, symname); 1511 } 1512 if (!is_vmlinux(modname) || 1513 (is_vmlinux(modname) && vmlinux_section_warnings)) 1514 check_sec_ref(mod, modname, &info); 1515 1516 version = get_modinfo(info.modinfo, info.modinfo_len, "version"); 1517 if (version) 1518 maybe_frob_rcs_version(modname, version, info.modinfo, 1519 version - (char *)info.hdr); 1520 if (version || (all_versions && !is_vmlinux(modname))) 1521 get_src_version(modname, mod->srcversion, 1522 sizeof(mod->srcversion)-1); 1523 1524 parse_elf_finish(&info); 1525 1526 /* Our trick to get versioning for struct_module - it's 1527 * never passed as an argument to an exported function, so 1528 * the automatic versioning doesn't pick it up, but it's really 1529 * important anyhow */ 1530 if (modversions) 1531 mod->unres = alloc_symbol("struct_module", 0, mod->unres); 1532 } 1533 1534 #define SZ 500 1535 1536 /* We first write the generated file into memory using the 1537 * following helper, then compare to the file on disk and 1538 * only update the later if anything changed */ 1539 1540 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 1541 const char *fmt, ...) 1542 { 1543 char tmp[SZ]; 1544 int len; 1545 va_list ap; 1546 1547 va_start(ap, fmt); 1548 len = vsnprintf(tmp, SZ, fmt, ap); 1549 buf_write(buf, tmp, len); 1550 va_end(ap); 1551 } 1552 1553 void buf_write(struct buffer *buf, const char *s, int len) 1554 { 1555 if (buf->size - buf->pos < len) { 1556 buf->size += len + SZ; 1557 buf->p = realloc(buf->p, buf->size); 1558 } 1559 strncpy(buf->p + buf->pos, s, len); 1560 buf->pos += len; 1561 } 1562 1563 static void check_for_gpl_usage(enum export exp, const char *m, const char *s) 1564 { 1565 const char *e = is_vmlinux(m) ?"":".ko"; 1566 1567 switch (exp) { 1568 case export_gpl: 1569 fatal("modpost: GPL-incompatible module %s%s " 1570 "uses GPL-only symbol '%s'\n", m, e, s); 1571 break; 1572 case export_unused_gpl: 1573 fatal("modpost: GPL-incompatible module %s%s " 1574 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s); 1575 break; 1576 case export_gpl_future: 1577 warn("modpost: GPL-incompatible module %s%s " 1578 "uses future GPL-only symbol '%s'\n", m, e, s); 1579 break; 1580 case export_plain: 1581 case export_unused: 1582 case export_unknown: 1583 /* ignore */ 1584 break; 1585 } 1586 } 1587 1588 static void check_for_unused(enum export exp, const char *m, const char *s) 1589 { 1590 const char *e = is_vmlinux(m) ?"":".ko"; 1591 1592 switch (exp) { 1593 case export_unused: 1594 case export_unused_gpl: 1595 warn("modpost: module %s%s " 1596 "uses symbol '%s' marked UNUSED\n", m, e, s); 1597 break; 1598 default: 1599 /* ignore */ 1600 break; 1601 } 1602 } 1603 1604 static void check_exports(struct module *mod) 1605 { 1606 struct symbol *s, *exp; 1607 1608 for (s = mod->unres; s; s = s->next) { 1609 const char *basename; 1610 exp = find_symbol(s->name); 1611 if (!exp || exp->module == mod) 1612 continue; 1613 basename = strrchr(mod->name, '/'); 1614 if (basename) 1615 basename++; 1616 else 1617 basename = mod->name; 1618 if (!mod->gpl_compatible) 1619 check_for_gpl_usage(exp->export, basename, exp->name); 1620 check_for_unused(exp->export, basename, exp->name); 1621 } 1622 } 1623 1624 /** 1625 * Header for the generated file 1626 **/ 1627 static void add_header(struct buffer *b, struct module *mod) 1628 { 1629 buf_printf(b, "#include <linux/module.h>\n"); 1630 buf_printf(b, "#include <linux/vermagic.h>\n"); 1631 buf_printf(b, "#include <linux/compiler.h>\n"); 1632 buf_printf(b, "\n"); 1633 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 1634 buf_printf(b, "\n"); 1635 buf_printf(b, "struct module __this_module\n"); 1636 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 1637 buf_printf(b, " .name = KBUILD_MODNAME,\n"); 1638 if (mod->has_init) 1639 buf_printf(b, " .init = init_module,\n"); 1640 if (mod->has_cleanup) 1641 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 1642 " .exit = cleanup_module,\n" 1643 "#endif\n"); 1644 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n"); 1645 buf_printf(b, "};\n"); 1646 } 1647 1648 /** 1649 * Record CRCs for unresolved symbols 1650 **/ 1651 static int add_versions(struct buffer *b, struct module *mod) 1652 { 1653 struct symbol *s, *exp; 1654 int err = 0; 1655 1656 for (s = mod->unres; s; s = s->next) { 1657 exp = find_symbol(s->name); 1658 if (!exp || exp->module == mod) { 1659 if (have_vmlinux && !s->weak) { 1660 if (warn_unresolved) { 1661 warn("\"%s\" [%s.ko] undefined!\n", 1662 s->name, mod->name); 1663 } else { 1664 merror("\"%s\" [%s.ko] undefined!\n", 1665 s->name, mod->name); 1666 err = 1; 1667 } 1668 } 1669 continue; 1670 } 1671 s->module = exp->module; 1672 s->crc_valid = exp->crc_valid; 1673 s->crc = exp->crc; 1674 } 1675 1676 if (!modversions) 1677 return err; 1678 1679 buf_printf(b, "\n"); 1680 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 1681 buf_printf(b, "__used\n"); 1682 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 1683 1684 for (s = mod->unres; s; s = s->next) { 1685 if (!s->module) 1686 continue; 1687 if (!s->crc_valid) { 1688 warn("\"%s\" [%s.ko] has no CRC!\n", 1689 s->name, mod->name); 1690 continue; 1691 } 1692 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); 1693 } 1694 1695 buf_printf(b, "};\n"); 1696 1697 return err; 1698 } 1699 1700 static void add_depends(struct buffer *b, struct module *mod, 1701 struct module *modules) 1702 { 1703 struct symbol *s; 1704 struct module *m; 1705 int first = 1; 1706 1707 for (m = modules; m; m = m->next) 1708 m->seen = is_vmlinux(m->name); 1709 1710 buf_printf(b, "\n"); 1711 buf_printf(b, "static const char __module_depends[]\n"); 1712 buf_printf(b, "__used\n"); 1713 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 1714 buf_printf(b, "\"depends="); 1715 for (s = mod->unres; s; s = s->next) { 1716 const char *p; 1717 if (!s->module) 1718 continue; 1719 1720 if (s->module->seen) 1721 continue; 1722 1723 s->module->seen = 1; 1724 p = strrchr(s->module->name, '/'); 1725 if (p) 1726 p++; 1727 else 1728 p = s->module->name; 1729 buf_printf(b, "%s%s", first ? "" : ",", p); 1730 first = 0; 1731 } 1732 buf_printf(b, "\";\n"); 1733 } 1734 1735 static void add_srcversion(struct buffer *b, struct module *mod) 1736 { 1737 if (mod->srcversion[0]) { 1738 buf_printf(b, "\n"); 1739 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 1740 mod->srcversion); 1741 } 1742 } 1743 1744 static void write_if_changed(struct buffer *b, const char *fname) 1745 { 1746 char *tmp; 1747 FILE *file; 1748 struct stat st; 1749 1750 file = fopen(fname, "r"); 1751 if (!file) 1752 goto write; 1753 1754 if (fstat(fileno(file), &st) < 0) 1755 goto close_write; 1756 1757 if (st.st_size != b->pos) 1758 goto close_write; 1759 1760 tmp = NOFAIL(malloc(b->pos)); 1761 if (fread(tmp, 1, b->pos, file) != b->pos) 1762 goto free_write; 1763 1764 if (memcmp(tmp, b->p, b->pos) != 0) 1765 goto free_write; 1766 1767 free(tmp); 1768 fclose(file); 1769 return; 1770 1771 free_write: 1772 free(tmp); 1773 close_write: 1774 fclose(file); 1775 write: 1776 file = fopen(fname, "w"); 1777 if (!file) { 1778 perror(fname); 1779 exit(1); 1780 } 1781 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 1782 perror(fname); 1783 exit(1); 1784 } 1785 fclose(file); 1786 } 1787 1788 /* parse Module.symvers file. line format: 1789 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something] 1790 **/ 1791 static void read_dump(const char *fname, unsigned int kernel) 1792 { 1793 unsigned long size, pos = 0; 1794 void *file = grab_file(fname, &size); 1795 char *line; 1796 1797 if (!file) 1798 /* No symbol versions, silently ignore */ 1799 return; 1800 1801 while ((line = get_next_line(&pos, file, size))) { 1802 char *symname, *modname, *d, *export, *end; 1803 unsigned int crc; 1804 struct module *mod; 1805 struct symbol *s; 1806 1807 if (!(symname = strchr(line, '\t'))) 1808 goto fail; 1809 *symname++ = '\0'; 1810 if (!(modname = strchr(symname, '\t'))) 1811 goto fail; 1812 *modname++ = '\0'; 1813 if ((export = strchr(modname, '\t')) != NULL) 1814 *export++ = '\0'; 1815 if (export && ((end = strchr(export, '\t')) != NULL)) 1816 *end = '\0'; 1817 crc = strtoul(line, &d, 16); 1818 if (*symname == '\0' || *modname == '\0' || *d != '\0') 1819 goto fail; 1820 mod = find_module(modname); 1821 if (!mod) { 1822 if (is_vmlinux(modname)) 1823 have_vmlinux = 1; 1824 mod = new_module(NOFAIL(strdup(modname))); 1825 mod->skip = 1; 1826 } 1827 s = sym_add_exported(symname, mod, export_no(export)); 1828 s->kernel = kernel; 1829 s->preloaded = 1; 1830 sym_update_crc(symname, mod, crc, export_no(export)); 1831 } 1832 return; 1833 fail: 1834 fatal("parse error in symbol dump file\n"); 1835 } 1836 1837 /* For normal builds always dump all symbols. 1838 * For external modules only dump symbols 1839 * that are not read from kernel Module.symvers. 1840 **/ 1841 static int dump_sym(struct symbol *sym) 1842 { 1843 if (!external_module) 1844 return 1; 1845 if (sym->vmlinux || sym->kernel) 1846 return 0; 1847 return 1; 1848 } 1849 1850 static void write_dump(const char *fname) 1851 { 1852 struct buffer buf = { }; 1853 struct symbol *symbol; 1854 int n; 1855 1856 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 1857 symbol = symbolhash[n]; 1858 while (symbol) { 1859 if (dump_sym(symbol)) 1860 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", 1861 symbol->crc, symbol->name, 1862 symbol->module->name, 1863 export_str(symbol->export)); 1864 symbol = symbol->next; 1865 } 1866 } 1867 write_if_changed(&buf, fname); 1868 } 1869 1870 int main(int argc, char **argv) 1871 { 1872 struct module *mod; 1873 struct buffer buf = { }; 1874 char *kernel_read = NULL, *module_read = NULL; 1875 char *dump_write = NULL; 1876 int opt; 1877 int err; 1878 1879 while ((opt = getopt(argc, argv, "i:I:msSo:aw")) != -1) { 1880 switch (opt) { 1881 case 'i': 1882 kernel_read = optarg; 1883 break; 1884 case 'I': 1885 module_read = optarg; 1886 external_module = 1; 1887 break; 1888 case 'm': 1889 modversions = 1; 1890 break; 1891 case 'o': 1892 dump_write = optarg; 1893 break; 1894 case 'a': 1895 all_versions = 1; 1896 break; 1897 case 's': 1898 vmlinux_section_warnings = 0; 1899 break; 1900 case 'S': 1901 sec_mismatch_verbose = 0; 1902 break; 1903 case 'w': 1904 warn_unresolved = 1; 1905 break; 1906 default: 1907 exit(1); 1908 } 1909 } 1910 1911 if (kernel_read) 1912 read_dump(kernel_read, 1); 1913 if (module_read) 1914 read_dump(module_read, 0); 1915 1916 while (optind < argc) 1917 read_symbols(argv[optind++]); 1918 1919 for (mod = modules; mod; mod = mod->next) { 1920 if (mod->skip) 1921 continue; 1922 check_exports(mod); 1923 } 1924 1925 err = 0; 1926 1927 for (mod = modules; mod; mod = mod->next) { 1928 char fname[strlen(mod->name) + 10]; 1929 1930 if (mod->skip) 1931 continue; 1932 1933 buf.pos = 0; 1934 1935 add_header(&buf, mod); 1936 err |= add_versions(&buf, mod); 1937 add_depends(&buf, mod, modules); 1938 add_moddevtable(&buf, mod); 1939 add_srcversion(&buf, mod); 1940 1941 sprintf(fname, "%s.mod.c", mod->name); 1942 write_if_changed(&buf, fname); 1943 } 1944 1945 if (dump_write) 1946 write_dump(dump_write); 1947 if (sec_mismatch_count && !sec_mismatch_verbose) 1948 warn("modpost: Found %d section mismatch(es).\n" 1949 "To see full details build your kernel with:\n" 1950 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n", 1951 sec_mismatch_count); 1952 1953 return err; 1954 } 1955