1 /* Postprocess module symbol versions
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
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
11 * Usage: modpost vmlinux module1.o module2.o ...
22 #include "../../include/linux/license.h"
24 /* Are we using CONFIG_MODVERSIONS? */
25 static int modversions = 0;
26 /* Warn about undefined symbols? (do so if we have vmlinux) */
27 static int have_vmlinux = 0;
28 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
29 static int all_versions = 0;
30 /* If we are modposting external module set to 1 */
31 static int external_module = 0;
32 /* Warn about section mismatch in vmlinux if set to 1 */
33 static int vmlinux_section_warnings = 1;
34 /* Only warn about unresolved symbols */
35 static int warn_unresolved = 0;
36 /* How a symbol is exported */
37 static int sec_mismatch_count = 0;
38 static int sec_mismatch_verbose = 1;
39 static int sec_mismatch_fatal = 0;
40 /* ignore missing files */
41 static int ignore_missing_files;
44 export_plain, export_unused, export_gpl,
45 export_unused_gpl, export_gpl_future, export_unknown
48 /* In kernel, this size is defined in linux/module.h;
49 * here we use Elf_Addr instead of long for covering cross-compile
52 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
54 #define PRINTF __attribute__ ((format (printf, 1, 2)))
56 PRINTF void fatal(const char *fmt, ...)
60 fprintf(stderr, "FATAL: ");
62 va_start(arglist, fmt);
63 vfprintf(stderr, fmt, arglist);
69 PRINTF void warn(const char *fmt, ...)
73 fprintf(stderr, "WARNING: ");
75 va_start(arglist, fmt);
76 vfprintf(stderr, fmt, arglist);
80 PRINTF void merror(const char *fmt, ...)
84 fprintf(stderr, "ERROR: ");
86 va_start(arglist, fmt);
87 vfprintf(stderr, fmt, arglist);
91 static inline bool strends(const char *str, const char *postfix)
93 if (strlen(str) < strlen(postfix))
96 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
99 static int is_vmlinux(const char *modname)
103 myname = strrchr(modname, '/');
109 return (strcmp(myname, "vmlinux") == 0) ||
110 (strcmp(myname, "vmlinux.o") == 0);
113 void *do_nofail(void *ptr, const char *expr)
116 fatal("modpost: Memory allocation failure: %s.\n", expr);
121 /* A list of all modules we processed */
122 static struct module *modules;
124 static struct module *find_module(const char *modname)
128 for (mod = modules; mod; mod = mod->next)
129 if (strcmp(mod->name, modname) == 0)
134 static struct module *new_module(const char *modname)
139 mod = NOFAIL(malloc(sizeof(*mod)));
140 memset(mod, 0, sizeof(*mod));
141 p = NOFAIL(strdup(modname));
143 /* strip trailing .o */
144 if (strends(p, ".o")) {
145 p[strlen(p) - 2] = '\0';
151 mod->gpl_compatible = -1;
158 /* A hash of all exported symbols,
159 * struct symbol is also used for lists of unresolved symbols */
161 #define SYMBOL_HASH_SIZE 1024
165 struct module *module;
169 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
170 unsigned int kernel:1; /* 1 if symbol is from kernel
171 * (only for external modules) **/
172 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
173 enum export export; /* Type of export */
177 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
179 /* This is based on the hash agorithm from gdbm, via tdb */
180 static inline unsigned int tdb_hash(const char *name)
182 unsigned value; /* Used to compute the hash value. */
183 unsigned i; /* Used to cycle through random values. */
185 /* Set the initial value from the key size. */
186 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
187 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
189 return (1103515243 * value + 12345);
193 * Allocate a new symbols for use in the hash of exported symbols or
194 * the list of unresolved symbols per module
196 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
199 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
201 memset(s, 0, sizeof(*s));
202 strcpy(s->name, name);
208 /* For the hash of exported symbols */
209 static struct symbol *new_symbol(const char *name, struct module *module,
215 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
216 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
217 new->module = module;
218 new->export = export;
222 static struct symbol *find_symbol(const char *name)
226 /* For our purposes, .foo matches foo. PPC64 needs this. */
230 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
231 if (strcmp(s->name, name) == 0)
237 static const struct {
241 { .str = "EXPORT_SYMBOL", .export = export_plain },
242 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
243 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
244 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
245 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
246 { .str = "(unknown)", .export = export_unknown },
250 static const char *export_str(enum export ex)
252 return export_list[ex].str;
255 static enum export export_no(const char *s)
260 return export_unknown;
261 for (i = 0; export_list[i].export != export_unknown; i++) {
262 if (strcmp(export_list[i].str, s) == 0)
263 return export_list[i].export;
265 return export_unknown;
268 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
270 return (void *)elf->hdr +
271 elf->sechdrs[elf->secindex_strings].sh_offset +
275 static const char *sec_name(struct elf_info *elf, int secindex)
277 return sech_name(elf, &elf->sechdrs[secindex]);
280 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
282 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
284 const char *secname = sec_name(elf, sec);
286 if (strstarts(secname, "___ksymtab+"))
288 else if (strstarts(secname, "___ksymtab_unused+"))
289 return export_unused;
290 else if (strstarts(secname, "___ksymtab_gpl+"))
292 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
293 return export_unused_gpl;
294 else if (strstarts(secname, "___ksymtab_gpl_future+"))
295 return export_gpl_future;
297 return export_unknown;
300 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
302 if (sec == elf->export_sec)
304 else if (sec == elf->export_unused_sec)
305 return export_unused;
306 else if (sec == elf->export_gpl_sec)
308 else if (sec == elf->export_unused_gpl_sec)
309 return export_unused_gpl;
310 else if (sec == elf->export_gpl_future_sec)
311 return export_gpl_future;
313 return export_unknown;
317 * Add an exported symbol - it may have already been added without a
318 * CRC, in this case just update the CRC
320 static struct symbol *sym_add_exported(const char *name, struct module *mod,
323 struct symbol *s = find_symbol(name);
326 s = new_symbol(name, mod, export);
329 warn("%s: '%s' exported twice. Previous export "
330 "was in %s%s\n", mod->name, name,
332 is_vmlinux(s->module->name) ?"":".ko");
334 /* In case Module.symvers was out of date */
339 s->vmlinux = is_vmlinux(mod->name);
345 static void sym_update_crc(const char *name, struct module *mod,
346 unsigned int crc, enum export export)
348 struct symbol *s = find_symbol(name);
351 s = new_symbol(name, mod, export);
352 /* Don't complain when we find it later. */
359 void *grab_file(const char *filename, unsigned long *size)
362 void *map = MAP_FAILED;
365 fd = open(filename, O_RDONLY);
372 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
376 if (map == MAP_FAILED)
382 * Return a copy of the next line in a mmap'ed file.
383 * spaces in the beginning of the line is trimmed away.
384 * Return a pointer to a static buffer.
386 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
388 static char line[4096];
391 signed char *p = (signed char *)file + *pos;
394 for (; *pos < size ; (*pos)++) {
395 if (skip && isspace(*p)) {
400 if (*p != '\n' && (*pos < size)) {
404 break; /* Too long, stop */
415 void release_file(void *file, unsigned long size)
420 static int parse_elf(struct elf_info *info, const char *filename)
426 const char *secstrings;
427 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
429 hdr = grab_file(filename, &info->size);
431 if (ignore_missing_files) {
432 fprintf(stderr, "%s: %s (ignored)\n", filename,
440 if (info->size < sizeof(*hdr)) {
441 /* file too small, assume this is an empty .o file */
444 /* Is this a valid ELF file? */
445 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
446 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
447 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
448 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
449 /* Not an ELF file - silently ignore it */
452 /* Fix endianness in ELF header */
453 hdr->e_type = TO_NATIVE(hdr->e_type);
454 hdr->e_machine = TO_NATIVE(hdr->e_machine);
455 hdr->e_version = TO_NATIVE(hdr->e_version);
456 hdr->e_entry = TO_NATIVE(hdr->e_entry);
457 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
458 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
459 hdr->e_flags = TO_NATIVE(hdr->e_flags);
460 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
461 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
462 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
463 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
464 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
465 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
466 sechdrs = (void *)hdr + hdr->e_shoff;
467 info->sechdrs = sechdrs;
469 /* Check if file offset is correct */
470 if (hdr->e_shoff > info->size) {
471 fatal("section header offset=%lu in file '%s' is bigger than "
472 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
473 filename, info->size);
477 if (hdr->e_shnum == SHN_UNDEF) {
479 * There are more than 64k sections,
480 * read count from .sh_size.
482 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
485 info->num_sections = hdr->e_shnum;
487 if (hdr->e_shstrndx == SHN_XINDEX) {
488 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
491 info->secindex_strings = hdr->e_shstrndx;
494 /* Fix endianness in section headers */
495 for (i = 0; i < info->num_sections; i++) {
496 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
497 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
498 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
499 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
500 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
501 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
502 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
503 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
504 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
505 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
507 /* Find symbol table. */
508 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
509 for (i = 1; i < info->num_sections; i++) {
511 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
513 if (!nobits && sechdrs[i].sh_offset > info->size) {
514 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
515 "sizeof(*hrd)=%zu\n", filename,
516 (unsigned long)sechdrs[i].sh_offset,
520 secname = secstrings + sechdrs[i].sh_name;
521 if (strcmp(secname, ".modinfo") == 0) {
523 fatal("%s has NOBITS .modinfo\n", filename);
524 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
525 info->modinfo_len = sechdrs[i].sh_size;
526 } else if (strcmp(secname, "__ksymtab") == 0)
527 info->export_sec = i;
528 else if (strcmp(secname, "__ksymtab_unused") == 0)
529 info->export_unused_sec = i;
530 else if (strcmp(secname, "__ksymtab_gpl") == 0)
531 info->export_gpl_sec = i;
532 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
533 info->export_unused_gpl_sec = i;
534 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
535 info->export_gpl_future_sec = i;
537 if (sechdrs[i].sh_type == SHT_SYMTAB) {
538 unsigned int sh_link_idx;
540 info->symtab_start = (void *)hdr +
541 sechdrs[i].sh_offset;
542 info->symtab_stop = (void *)hdr +
543 sechdrs[i].sh_offset + sechdrs[i].sh_size;
544 sh_link_idx = sechdrs[i].sh_link;
545 info->strtab = (void *)hdr +
546 sechdrs[sh_link_idx].sh_offset;
549 /* 32bit section no. table? ("more than 64k sections") */
550 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
551 symtab_shndx_idx = i;
552 info->symtab_shndx_start = (void *)hdr +
553 sechdrs[i].sh_offset;
554 info->symtab_shndx_stop = (void *)hdr +
555 sechdrs[i].sh_offset + sechdrs[i].sh_size;
558 if (!info->symtab_start)
559 fatal("%s has no symtab?\n", filename);
561 /* Fix endianness in symbols */
562 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
563 sym->st_shndx = TO_NATIVE(sym->st_shndx);
564 sym->st_name = TO_NATIVE(sym->st_name);
565 sym->st_value = TO_NATIVE(sym->st_value);
566 sym->st_size = TO_NATIVE(sym->st_size);
569 if (symtab_shndx_idx != ~0U) {
571 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
572 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
573 filename, sechdrs[symtab_shndx_idx].sh_link,
576 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
584 static void parse_elf_finish(struct elf_info *info)
586 release_file(info->hdr, info->size);
589 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
591 /* ignore __this_module, it will be resolved shortly */
592 if (strcmp(symname, "__this_module") == 0)
594 /* ignore global offset table */
595 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
597 if (info->hdr->e_machine == EM_PPC)
598 /* Special register function linked on all modules during final link of .ko */
599 if (strstarts(symname, "_restgpr_") ||
600 strstarts(symname, "_savegpr_") ||
601 strstarts(symname, "_rest32gpr_") ||
602 strstarts(symname, "_save32gpr_") ||
603 strstarts(symname, "_restvr_") ||
604 strstarts(symname, "_savevr_"))
606 if (info->hdr->e_machine == EM_PPC64)
607 /* Special register function linked on all modules during final link of .ko */
608 if (strstarts(symname, "_restgpr0_") ||
609 strstarts(symname, "_savegpr0_") ||
610 strstarts(symname, "_restvr_") ||
611 strstarts(symname, "_savevr_") ||
612 strcmp(symname, ".TOC.") == 0)
614 /* Do not ignore this symbol */
618 static void handle_modversions(struct module *mod, struct elf_info *info,
619 Elf_Sym *sym, const char *symname)
625 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
626 strstarts(symname, "__ksymtab"))
627 export = export_from_secname(info, get_secindex(info, sym));
629 export = export_from_sec(info, get_secindex(info, sym));
632 if (strstarts(symname, "__crc_")) {
634 crc = (unsigned int) sym->st_value;
635 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
638 /* symbol points to the CRC in the ELF object */
639 crcp = (void *)info->hdr + sym->st_value +
640 info->sechdrs[sym->st_shndx].sh_offset -
641 (info->hdr->e_type != ET_REL ?
642 info->sechdrs[sym->st_shndx].sh_addr : 0);
645 sym_update_crc(symname + strlen("__crc_"), mod, crc,
649 switch (sym->st_shndx) {
651 if (strstarts(symname, "__gnu_lto_")) {
652 /* Should warn here, but modpost runs before the linker */
654 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
657 /* undefined symbol */
658 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
659 ELF_ST_BIND(sym->st_info) != STB_WEAK)
661 if (ignore_undef_symbol(info, symname))
663 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
664 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
665 /* add compatibility with older glibc */
666 #ifndef STT_SPARC_REGISTER
667 #define STT_SPARC_REGISTER STT_REGISTER
669 if (info->hdr->e_machine == EM_SPARC ||
670 info->hdr->e_machine == EM_SPARCV9) {
671 /* Ignore register directives. */
672 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
674 if (symname[0] == '.') {
675 char *munged = NOFAIL(strdup(symname));
677 munged[1] = toupper(munged[1]);
684 const char *e = is_vmlinux(mod->name) ?"":".ko";
685 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
686 symname + strlen("__crc_"), mod->name, e);
688 mod->unres = alloc_symbol(symname,
689 ELF_ST_BIND(sym->st_info) == STB_WEAK,
693 /* All exported symbols */
694 if (strstarts(symname, "__ksymtab_")) {
695 sym_add_exported(symname + strlen("__ksymtab_"), mod,
698 if (strcmp(symname, "init_module") == 0)
700 if (strcmp(symname, "cleanup_module") == 0)
701 mod->has_cleanup = 1;
707 * Parse tag=value strings from .modinfo section
709 static char *next_string(char *string, unsigned long *secsize)
711 /* Skip non-zero chars */
714 if ((*secsize)-- <= 1)
718 /* Skip any zero padding. */
721 if ((*secsize)-- <= 1)
727 static char *get_next_modinfo(struct elf_info *info, const char *tag,
731 unsigned int taglen = strlen(tag);
732 char *modinfo = info->modinfo;
733 unsigned long size = info->modinfo_len;
736 size -= prev - modinfo;
737 modinfo = next_string(prev, &size);
740 for (p = modinfo; p; p = next_string(p, &size)) {
741 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
742 return p + taglen + 1;
747 static char *get_modinfo(struct elf_info *info, const char *tag)
750 return get_next_modinfo(info, tag, NULL);
754 * Test if string s ends in string sub
757 static int strrcmp(const char *s, const char *sub)
765 sublen = strlen(sub);
767 if ((slen == 0) || (sublen == 0))
773 return memcmp(s + slen - sublen, sub, sublen);
776 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
779 return elf->strtab + sym->st_name;
784 /* The pattern is an array of simple patterns.
785 * "foo" will match an exact string equal to "foo"
786 * "*foo" will match a string that ends with "foo"
787 * "foo*" will match a string that begins with "foo"
788 * "*foo*" will match a string that contains "foo"
790 static int match(const char *sym, const char * const pat[])
795 const char *endp = p + strlen(p) - 1;
798 if (*p == '*' && *endp == '*') {
799 char *here, *bare = strndup(p + 1, strlen(p) - 2);
801 here = strstr(sym, bare);
807 else if (*p == '*') {
808 if (strrcmp(sym, p + 1) == 0)
812 else if (*endp == '*') {
813 if (strncmp(sym, p, strlen(p) - 1) == 0)
818 if (strcmp(p, sym) == 0)
826 /* sections that we do not want to do full section mismatch check on */
827 static const char *const section_white_list[] =
831 ".cranges", /* sh64 */
832 ".zdebug*", /* Compressed debug sections. */
833 ".GCC.command.line", /* record-gcc-switches */
834 ".mdebug*", /* alpha, score, mips etc. */
835 ".pdr", /* alpha, score, mips etc. */
840 ".xt.prop", /* xtensa */
841 ".xt.lit", /* xtensa */
842 ".arcextmap*", /* arc */
843 ".gnu.linkonce.arcext*", /* arc : modules */
844 ".cmem*", /* EZchip */
845 ".fmt_slot*", /* EZchip */
852 * This is used to find sections missing the SHF_ALLOC flag.
853 * The cause of this is often a section specified in assembler
854 * without "ax" / "aw".
856 static void check_section(const char *modname, struct elf_info *elf,
859 const char *sec = sech_name(elf, sechdr);
861 if (sechdr->sh_type == SHT_PROGBITS &&
862 !(sechdr->sh_flags & SHF_ALLOC) &&
863 !match(sec, section_white_list)) {
864 warn("%s (%s): unexpected non-allocatable section.\n"
865 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
866 "Note that for example <linux/init.h> contains\n"
867 "section definitions for use in .S files.\n\n",
874 #define ALL_INIT_DATA_SECTIONS \
875 ".init.setup", ".init.rodata", ".meminit.rodata", \
876 ".init.data", ".meminit.data"
877 #define ALL_EXIT_DATA_SECTIONS \
878 ".exit.data", ".memexit.data"
880 #define ALL_INIT_TEXT_SECTIONS \
881 ".init.text", ".meminit.text"
882 #define ALL_EXIT_TEXT_SECTIONS \
883 ".exit.text", ".memexit.text"
885 #define ALL_PCI_INIT_SECTIONS \
886 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
887 ".pci_fixup_enable", ".pci_fixup_resume", \
888 ".pci_fixup_resume_early", ".pci_fixup_suspend"
890 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
891 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
893 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
894 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
896 #define DATA_SECTIONS ".data", ".data.rel"
897 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
898 ".kprobes.text", ".cpuidle.text"
899 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
900 ".fixup", ".entry.text", ".exception.text", ".text.*", \
903 #define INIT_SECTIONS ".init.*"
904 #define MEM_INIT_SECTIONS ".meminit.*"
906 #define EXIT_SECTIONS ".exit.*"
907 #define MEM_EXIT_SECTIONS ".memexit.*"
909 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
910 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
912 /* init data sections */
913 static const char *const init_data_sections[] =
914 { ALL_INIT_DATA_SECTIONS, NULL };
916 /* all init sections */
917 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
919 /* All init and exit sections (code + data) */
920 static const char *const init_exit_sections[] =
921 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
923 /* all text sections */
924 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
927 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
930 /* symbols in .data that may refer to init/exit sections */
931 #define DEFAULT_SYMBOL_WHITE_LIST \
933 "*_template", /* scsi uses *_template a lot */ \
934 "*_timer", /* arm uses ops structures named _timer a lot */ \
935 "*_sht", /* scsi also used *_sht to some extent */ \
941 static const char *const head_sections[] = { ".head.text*", NULL };
942 static const char *const linker_symbols[] =
943 { "__init_begin", "_sinittext", "_einittext", NULL };
944 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
951 XXXINIT_TO_SOME_INIT,
952 XXXEXIT_TO_SOME_EXIT,
953 ANY_INIT_TO_ANY_EXIT,
954 ANY_EXIT_TO_ANY_INIT,
960 * Describe how to match sections on different criterias:
962 * @fromsec: Array of sections to be matched.
964 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
965 * this array is forbidden (black-list). Can be empty.
967 * @good_tosec: Relocations applied to a section in @fromsec must be
968 * targetting sections in this array (white-list). Can be empty.
970 * @mismatch: Type of mismatch.
972 * @symbol_white_list: Do not match a relocation to a symbol in this list
973 * even if it is targetting a section in @bad_to_sec.
975 * @handler: Specific handler to call when a match is found. If NULL,
976 * default_mismatch_handler() will be called.
979 struct sectioncheck {
980 const char *fromsec[20];
981 const char *bad_tosec[20];
982 const char *good_tosec[20];
983 enum mismatch mismatch;
984 const char *symbol_white_list[20];
985 void (*handler)(const char *modname, struct elf_info *elf,
986 const struct sectioncheck* const mismatch,
987 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
991 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
992 const struct sectioncheck* const mismatch,
993 Elf_Rela *r, Elf_Sym *sym,
994 const char *fromsec);
996 static const struct sectioncheck sectioncheck[] = {
997 /* Do not reference init/exit code/data from
998 * normal code and data
1001 .fromsec = { TEXT_SECTIONS, NULL },
1002 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1003 .mismatch = TEXT_TO_ANY_INIT,
1004 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1007 .fromsec = { DATA_SECTIONS, NULL },
1008 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1009 .mismatch = DATA_TO_ANY_INIT,
1010 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1013 .fromsec = { DATA_SECTIONS, NULL },
1014 .bad_tosec = { INIT_SECTIONS, NULL },
1015 .mismatch = DATA_TO_ANY_INIT,
1016 .symbol_white_list = {
1017 "*_template", "*_timer", "*_sht", "*_ops",
1018 "*_probe", "*_probe_one", "*_console", NULL
1022 .fromsec = { TEXT_SECTIONS, NULL },
1023 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1024 .mismatch = TEXT_TO_ANY_EXIT,
1025 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1028 .fromsec = { DATA_SECTIONS, NULL },
1029 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1030 .mismatch = DATA_TO_ANY_EXIT,
1031 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1033 /* Do not reference init code/data from meminit code/data */
1035 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1036 .bad_tosec = { INIT_SECTIONS, NULL },
1037 .mismatch = XXXINIT_TO_SOME_INIT,
1038 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1040 /* Do not reference exit code/data from memexit code/data */
1042 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1043 .bad_tosec = { EXIT_SECTIONS, NULL },
1044 .mismatch = XXXEXIT_TO_SOME_EXIT,
1045 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1047 /* Do not use exit code/data from init code */
1049 .fromsec = { ALL_INIT_SECTIONS, NULL },
1050 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1051 .mismatch = ANY_INIT_TO_ANY_EXIT,
1052 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1054 /* Do not use init code/data from exit code */
1056 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1057 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1058 .mismatch = ANY_EXIT_TO_ANY_INIT,
1059 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1062 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1063 .bad_tosec = { INIT_SECTIONS, NULL },
1064 .mismatch = ANY_INIT_TO_ANY_EXIT,
1065 .symbol_white_list = { NULL },
1067 /* Do not export init/exit functions or data */
1069 .fromsec = { "__ksymtab*", NULL },
1070 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1071 .mismatch = EXPORT_TO_INIT_EXIT,
1072 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1075 .fromsec = { "__ex_table", NULL },
1076 /* If you're adding any new black-listed sections in here, consider
1077 * adding a special 'printer' for them in scripts/check_extable.
1079 .bad_tosec = { ".altinstr_replacement", NULL },
1080 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1081 .mismatch = EXTABLE_TO_NON_TEXT,
1082 .handler = extable_mismatch_handler,
1086 static const struct sectioncheck *section_mismatch(
1087 const char *fromsec, const char *tosec)
1090 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1091 const struct sectioncheck *check = §ioncheck[0];
1094 * The target section could be the SHT_NUL section when we're
1095 * handling relocations to un-resolved symbols, trying to match it
1096 * doesn't make much sense and causes build failures on parisc
1102 for (i = 0; i < elems; i++) {
1103 if (match(fromsec, check->fromsec)) {
1104 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1106 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1115 * Whitelist to allow certain references to pass with no warning.
1118 * If a module parameter is declared __initdata and permissions=0
1119 * then this is legal despite the warning generated.
1120 * We cannot see value of permissions here, so just ignore
1122 * The pattern is identified by:
1123 * tosec = .init.data
1128 * module_param_call() ops can refer to __init set function if permissions=0
1129 * The pattern is identified by:
1130 * tosec = .init.text
1132 * atsym = __param_ops_*
1135 * Many drivers utilise a *driver container with references to
1136 * add, remove, probe functions etc.
1137 * the pattern is identified by:
1138 * tosec = init or exit section
1139 * fromsec = data section
1140 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1141 * *probe_one, *_console, *_timer
1144 * Whitelist all references from .head.text to any init section
1147 * Some symbols belong to init section but still it is ok to reference
1148 * these from non-init sections as these symbols don't have any memory
1149 * allocated for them and symbol address and value are same. So even
1150 * if init section is freed, its ok to reference those symbols.
1151 * For ex. symbols marking the init section boundaries.
1152 * This pattern is identified by
1153 * refsymname = __init_begin, _sinittext, _einittext
1156 * GCC may optimize static inlines when fed constant arg(s) resulting
1157 * in functions like cpumask_empty() -- generating an associated symbol
1158 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1159 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1160 * meaningless section warning. May need to add isra symbols too...
1161 * This pattern is identified by
1162 * tosec = init section
1163 * fromsec = text section
1164 * refsymname = *.constprop.*
1167 static int secref_whitelist(const struct sectioncheck *mismatch,
1168 const char *fromsec, const char *fromsym,
1169 const char *tosec, const char *tosym)
1171 /* Check for pattern 1 */
1172 if (match(tosec, init_data_sections) &&
1173 match(fromsec, data_sections) &&
1174 strstarts(fromsym, "__param"))
1177 /* Check for pattern 1a */
1178 if (strcmp(tosec, ".init.text") == 0 &&
1179 match(fromsec, data_sections) &&
1180 strstarts(fromsym, "__param_ops_"))
1183 /* Check for pattern 2 */
1184 if (match(tosec, init_exit_sections) &&
1185 match(fromsec, data_sections) &&
1186 match(fromsym, mismatch->symbol_white_list))
1189 /* Check for pattern 3 */
1190 if (match(fromsec, head_sections) &&
1191 match(tosec, init_sections))
1194 /* Check for pattern 4 */
1195 if (match(tosym, linker_symbols))
1198 /* Check for pattern 5 */
1199 if (match(fromsec, text_sections) &&
1200 match(tosec, init_sections) &&
1201 match(fromsym, optim_symbols))
1208 * Find symbol based on relocation record info.
1209 * In some cases the symbol supplied is a valid symbol so
1210 * return refsym. If st_name != 0 we assume this is a valid symbol.
1211 * In other cases the symbol needs to be looked up in the symbol table
1212 * based on section and address.
1214 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1218 Elf_Sym *near = NULL;
1219 Elf64_Sword distance = 20;
1221 unsigned int relsym_secindex;
1223 if (relsym->st_name != 0)
1226 relsym_secindex = get_secindex(elf, relsym);
1227 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1228 if (get_secindex(elf, sym) != relsym_secindex)
1230 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1232 if (sym->st_value == addr)
1234 /* Find a symbol nearby - addr are maybe negative */
1235 d = sym->st_value - addr;
1237 d = addr - sym->st_value;
1243 /* We need a close match */
1250 static inline int is_arm_mapping_symbol(const char *str)
1252 return str[0] == '$' && strchr("axtd", str[1])
1253 && (str[2] == '\0' || str[2] == '.');
1257 * If there's no name there, ignore it; likewise, ignore it if it's
1258 * one of the magic symbols emitted used by current ARM tools.
1260 * Otherwise if find_symbols_between() returns those symbols, they'll
1261 * fail the whitelist tests and cause lots of false alarms ... fixable
1262 * only by merging __exit and __init sections into __text, bloating
1263 * the kernel (which is especially evil on embedded platforms).
1265 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1267 const char *name = elf->strtab + sym->st_name;
1269 if (!name || !strlen(name))
1271 return !is_arm_mapping_symbol(name);
1275 * Find symbols before or equal addr and after addr - in the section sec.
1276 * If we find two symbols with equal offset prefer one with a valid name.
1277 * The ELF format may have a better way to detect what type of symbol
1278 * it is, but this works for now.
1280 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1284 Elf_Sym *near = NULL;
1285 Elf_Addr distance = ~0;
1287 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1290 if (is_shndx_special(sym->st_shndx))
1292 symsec = sec_name(elf, get_secindex(elf, sym));
1293 if (strcmp(symsec, sec) != 0)
1295 if (!is_valid_name(elf, sym))
1297 if (sym->st_value <= addr) {
1298 if ((addr - sym->st_value) < distance) {
1299 distance = addr - sym->st_value;
1301 } else if ((addr - sym->st_value) == distance) {
1310 * Convert a section name to the function/data attribute
1311 * .init.text => __init
1312 * .memexitconst => __memconst
1315 * The memory of returned value has been allocated on a heap. The user of this
1316 * method should free it after usage.
1318 static char *sec2annotation(const char *s)
1320 if (match(s, init_exit_sections)) {
1321 char *p = NOFAIL(malloc(20));
1328 while (*s && *s != '.')
1333 if (strstr(s, "rodata") != NULL)
1334 strcat(p, "const ");
1335 else if (strstr(s, "data") != NULL)
1341 return NOFAIL(strdup(""));
1345 static int is_function(Elf_Sym *sym)
1348 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1353 static void print_section_list(const char * const list[20])
1355 const char *const *s = list;
1358 fprintf(stderr, "%s", *s);
1361 fprintf(stderr, ", ");
1363 fprintf(stderr, "\n");
1366 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1369 case 0: *name = "variable"; *name_p = ""; break;
1370 case 1: *name = "function"; *name_p = "()"; break;
1371 default: *name = "(unknown reference)"; *name_p = ""; break;
1376 * Print a warning about a section mismatch.
1377 * Try to find symbols near it so user can find it.
1378 * Check whitelist before warning - it may be a false positive.
1380 static void report_sec_mismatch(const char *modname,
1381 const struct sectioncheck *mismatch,
1382 const char *fromsec,
1383 unsigned long long fromaddr,
1384 const char *fromsym,
1386 const char *tosec, const char *tosym,
1389 const char *from, *from_p;
1390 const char *to, *to_p;
1394 sec_mismatch_count++;
1395 if (!sec_mismatch_verbose)
1398 get_pretty_name(from_is_func, &from, &from_p);
1399 get_pretty_name(to_is_func, &to, &to_p);
1401 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1402 "to the %s %s:%s%s\n",
1403 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1406 switch (mismatch->mismatch) {
1407 case TEXT_TO_ANY_INIT:
1408 prl_from = sec2annotation(fromsec);
1409 prl_to = sec2annotation(tosec);
1411 "The function %s%s() references\n"
1413 "This is often because %s lacks a %s\n"
1414 "annotation or the annotation of %s is wrong.\n",
1416 to, prl_to, tosym, to_p,
1417 fromsym, prl_to, tosym);
1421 case DATA_TO_ANY_INIT: {
1422 prl_to = sec2annotation(tosec);
1424 "The variable %s references\n"
1426 "If the reference is valid then annotate the\n"
1427 "variable with __init* or __refdata (see linux/init.h) "
1428 "or name the variable:\n",
1429 fromsym, to, prl_to, tosym, to_p);
1430 print_section_list(mismatch->symbol_white_list);
1434 case TEXT_TO_ANY_EXIT:
1435 prl_to = sec2annotation(tosec);
1437 "The function %s() references a %s in an exit section.\n"
1438 "Often the %s %s%s has valid usage outside the exit section\n"
1439 "and the fix is to remove the %sannotation of %s.\n",
1440 fromsym, to, to, tosym, to_p, prl_to, tosym);
1443 case DATA_TO_ANY_EXIT: {
1444 prl_to = sec2annotation(tosec);
1446 "The variable %s references\n"
1448 "If the reference is valid then annotate the\n"
1449 "variable with __exit* (see linux/init.h) or "
1450 "name the variable:\n",
1451 fromsym, to, prl_to, tosym, to_p);
1452 print_section_list(mismatch->symbol_white_list);
1456 case XXXINIT_TO_SOME_INIT:
1457 case XXXEXIT_TO_SOME_EXIT:
1458 prl_from = sec2annotation(fromsec);
1459 prl_to = sec2annotation(tosec);
1461 "The %s %s%s%s references\n"
1463 "If %s is only used by %s then\n"
1464 "annotate %s with a matching annotation.\n",
1465 from, prl_from, fromsym, from_p,
1466 to, prl_to, tosym, to_p,
1467 tosym, fromsym, tosym);
1471 case ANY_INIT_TO_ANY_EXIT:
1472 prl_from = sec2annotation(fromsec);
1473 prl_to = sec2annotation(tosec);
1475 "The %s %s%s%s references\n"
1477 "This is often seen when error handling "
1478 "in the init function\n"
1479 "uses functionality in the exit path.\n"
1480 "The fix is often to remove the %sannotation of\n"
1481 "%s%s so it may be used outside an exit section.\n",
1482 from, prl_from, fromsym, from_p,
1483 to, prl_to, tosym, to_p,
1484 prl_to, tosym, to_p);
1488 case ANY_EXIT_TO_ANY_INIT:
1489 prl_from = sec2annotation(fromsec);
1490 prl_to = sec2annotation(tosec);
1492 "The %s %s%s%s references\n"
1494 "This is often seen when error handling "
1495 "in the exit function\n"
1496 "uses functionality in the init path.\n"
1497 "The fix is often to remove the %sannotation of\n"
1498 "%s%s so it may be used outside an init section.\n",
1499 from, prl_from, fromsym, from_p,
1500 to, prl_to, tosym, to_p,
1501 prl_to, tosym, to_p);
1505 case EXPORT_TO_INIT_EXIT:
1506 prl_to = sec2annotation(tosec);
1508 "The symbol %s is exported and annotated %s\n"
1509 "Fix this by removing the %sannotation of %s "
1510 "or drop the export.\n",
1511 tosym, prl_to, prl_to, tosym);
1514 case EXTABLE_TO_NON_TEXT:
1515 fatal("There's a special handler for this mismatch type, "
1516 "we should never get here.");
1519 fprintf(stderr, "\n");
1522 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1523 const struct sectioncheck* const mismatch,
1524 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1530 const char *fromsym;
1532 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1533 fromsym = sym_name(elf, from);
1535 if (strstarts(fromsym, "reference___initcall"))
1538 tosec = sec_name(elf, get_secindex(elf, sym));
1539 to = find_elf_symbol(elf, r->r_addend, sym);
1540 tosym = sym_name(elf, to);
1542 /* check whitelist - we may ignore it */
1543 if (secref_whitelist(mismatch,
1544 fromsec, fromsym, tosec, tosym)) {
1545 report_sec_mismatch(modname, mismatch,
1546 fromsec, r->r_offset, fromsym,
1547 is_function(from), tosec, tosym,
1552 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1554 if (section_index > elf->num_sections)
1555 fatal("section_index is outside elf->num_sections!\n");
1557 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1561 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1562 * to know the sizeof(struct exception_table_entry) for the target architecture.
1564 static unsigned int extable_entry_size = 0;
1565 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1568 * If we're currently checking the second relocation within __ex_table,
1569 * that relocation offset tells us the offsetof(struct
1570 * exception_table_entry, fixup) which is equal to sizeof(struct
1571 * exception_table_entry) divided by two. We use that to our advantage
1572 * since there's no portable way to get that size as every architecture
1573 * seems to go with different sized types. Not pretty but better than
1574 * hard-coding the size for every architecture..
1576 if (!extable_entry_size)
1577 extable_entry_size = r->r_offset * 2;
1580 static inline bool is_extable_fault_address(Elf_Rela *r)
1583 * extable_entry_size is only discovered after we've handled the
1584 * _second_ relocation in __ex_table, so only abort when we're not
1585 * handling the first reloc and extable_entry_size is zero.
1587 if (r->r_offset && extable_entry_size == 0)
1588 fatal("extable_entry size hasn't been discovered!\n");
1590 return ((r->r_offset == 0) ||
1591 (r->r_offset % extable_entry_size == 0));
1594 #define is_second_extable_reloc(Start, Cur, Sec) \
1595 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1597 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1598 const struct sectioncheck* const mismatch,
1599 Elf_Rela* r, Elf_Sym* sym,
1600 const char* fromsec, const char* tosec)
1602 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1603 const char* fromsym_name = sym_name(elf, fromsym);
1604 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1605 const char* tosym_name = sym_name(elf, tosym);
1606 const char* from_pretty_name;
1607 const char* from_pretty_name_p;
1608 const char* to_pretty_name;
1609 const char* to_pretty_name_p;
1611 get_pretty_name(is_function(fromsym),
1612 &from_pretty_name, &from_pretty_name_p);
1613 get_pretty_name(is_function(tosym),
1614 &to_pretty_name, &to_pretty_name_p);
1616 warn("%s(%s+0x%lx): Section mismatch in reference"
1617 " from the %s %s%s to the %s %s:%s%s\n",
1618 modname, fromsec, (long)r->r_offset, from_pretty_name,
1619 fromsym_name, from_pretty_name_p,
1620 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1622 if (!match(tosec, mismatch->bad_tosec) &&
1623 is_executable_section(elf, get_secindex(elf, sym)))
1625 "The relocation at %s+0x%lx references\n"
1626 "section \"%s\" which is not in the list of\n"
1627 "authorized sections. If you're adding a new section\n"
1628 "and/or if this reference is valid, add \"%s\" to the\n"
1629 "list of authorized sections to jump to on fault.\n"
1630 "This can be achieved by adding \"%s\" to \n"
1631 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1632 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1635 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1636 const struct sectioncheck* const mismatch,
1637 Elf_Rela* r, Elf_Sym* sym,
1638 const char *fromsec)
1640 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1642 sec_mismatch_count++;
1644 if (sec_mismatch_verbose)
1645 report_extable_warnings(modname, elf, mismatch, r, sym,
1648 if (match(tosec, mismatch->bad_tosec))
1649 fatal("The relocation at %s+0x%lx references\n"
1650 "section \"%s\" which is black-listed.\n"
1651 "Something is seriously wrong and should be fixed.\n"
1652 "You might get more information about where this is\n"
1653 "coming from by using scripts/check_extable.sh %s\n",
1654 fromsec, (long)r->r_offset, tosec, modname);
1655 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1656 if (is_extable_fault_address(r))
1657 fatal("The relocation at %s+0x%lx references\n"
1658 "section \"%s\" which is not executable, IOW\n"
1659 "it is not possible for the kernel to fault\n"
1660 "at that address. Something is seriously wrong\n"
1661 "and should be fixed.\n",
1662 fromsec, (long)r->r_offset, tosec);
1664 fatal("The relocation at %s+0x%lx references\n"
1665 "section \"%s\" which is not executable, IOW\n"
1666 "the kernel will fault if it ever tries to\n"
1667 "jump to it. Something is seriously wrong\n"
1668 "and should be fixed.\n",
1669 fromsec, (long)r->r_offset, tosec);
1673 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1674 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1676 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1677 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1680 if (mismatch->handler)
1681 mismatch->handler(modname, elf, mismatch,
1684 default_mismatch_handler(modname, elf, mismatch,
1689 static unsigned int *reloc_location(struct elf_info *elf,
1690 Elf_Shdr *sechdr, Elf_Rela *r)
1692 Elf_Shdr *sechdrs = elf->sechdrs;
1693 int section = sechdr->sh_info;
1695 return (void *)elf->hdr + sechdrs[section].sh_offset +
1699 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1701 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1702 unsigned int *location = reloc_location(elf, sechdr, r);
1706 r->r_addend = TO_NATIVE(*location);
1709 r->r_addend = TO_NATIVE(*location) + 4;
1710 /* For CONFIG_RELOCATABLE=y */
1711 if (elf->hdr->e_type == ET_EXEC)
1712 r->r_addend += r->r_offset;
1719 #define R_ARM_CALL 28
1721 #ifndef R_ARM_JUMP24
1722 #define R_ARM_JUMP24 29
1725 #ifndef R_ARM_THM_CALL
1726 #define R_ARM_THM_CALL 10
1728 #ifndef R_ARM_THM_JUMP24
1729 #define R_ARM_THM_JUMP24 30
1731 #ifndef R_ARM_THM_JUMP19
1732 #define R_ARM_THM_JUMP19 51
1735 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1737 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1741 /* From ARM ABI: (S + A) | T */
1742 r->r_addend = (int)(long)
1743 (elf->symtab_start + ELF_R_SYM(r->r_info));
1748 case R_ARM_THM_CALL:
1749 case R_ARM_THM_JUMP24:
1750 case R_ARM_THM_JUMP19:
1751 /* From ARM ABI: ((S + A) | T) - P */
1752 r->r_addend = (int)(long)(elf->hdr +
1754 (r->r_offset - sechdr->sh_addr));
1762 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1764 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1765 unsigned int *location = reloc_location(elf, sechdr, r);
1768 if (r_typ == R_MIPS_HI16)
1769 return 1; /* skip this */
1770 inst = TO_NATIVE(*location);
1773 r->r_addend = inst & 0xffff;
1776 r->r_addend = (inst & 0x03ffffff) << 2;
1785 static void section_rela(const char *modname, struct elf_info *elf,
1792 const char *fromsec;
1794 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1795 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1797 fromsec = sech_name(elf, sechdr);
1798 fromsec += strlen(".rela");
1799 /* if from section (name) is know good then skip it */
1800 if (match(fromsec, section_white_list))
1803 for (rela = start; rela < stop; rela++) {
1804 r.r_offset = TO_NATIVE(rela->r_offset);
1805 #if KERNEL_ELFCLASS == ELFCLASS64
1806 if (elf->hdr->e_machine == EM_MIPS) {
1808 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1809 r_sym = TO_NATIVE(r_sym);
1810 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1811 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1813 r.r_info = TO_NATIVE(rela->r_info);
1814 r_sym = ELF_R_SYM(r.r_info);
1817 r.r_info = TO_NATIVE(rela->r_info);
1818 r_sym = ELF_R_SYM(r.r_info);
1820 r.r_addend = TO_NATIVE(rela->r_addend);
1821 sym = elf->symtab_start + r_sym;
1822 /* Skip special sections */
1823 if (is_shndx_special(sym->st_shndx))
1825 if (is_second_extable_reloc(start, rela, fromsec))
1826 find_extable_entry_size(fromsec, &r);
1827 check_section_mismatch(modname, elf, &r, sym, fromsec);
1831 static void section_rel(const char *modname, struct elf_info *elf,
1838 const char *fromsec;
1840 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1841 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1843 fromsec = sech_name(elf, sechdr);
1844 fromsec += strlen(".rel");
1845 /* if from section (name) is know good then skip it */
1846 if (match(fromsec, section_white_list))
1849 for (rel = start; rel < stop; rel++) {
1850 r.r_offset = TO_NATIVE(rel->r_offset);
1851 #if KERNEL_ELFCLASS == ELFCLASS64
1852 if (elf->hdr->e_machine == EM_MIPS) {
1854 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1855 r_sym = TO_NATIVE(r_sym);
1856 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1857 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1859 r.r_info = TO_NATIVE(rel->r_info);
1860 r_sym = ELF_R_SYM(r.r_info);
1863 r.r_info = TO_NATIVE(rel->r_info);
1864 r_sym = ELF_R_SYM(r.r_info);
1867 switch (elf->hdr->e_machine) {
1869 if (addend_386_rel(elf, sechdr, &r))
1873 if (addend_arm_rel(elf, sechdr, &r))
1877 if (addend_mips_rel(elf, sechdr, &r))
1881 sym = elf->symtab_start + r_sym;
1882 /* Skip special sections */
1883 if (is_shndx_special(sym->st_shndx))
1885 if (is_second_extable_reloc(start, rel, fromsec))
1886 find_extable_entry_size(fromsec, &r);
1887 check_section_mismatch(modname, elf, &r, sym, fromsec);
1892 * A module includes a number of sections that are discarded
1893 * either when loaded or when used as built-in.
1894 * For loaded modules all functions marked __init and all data
1895 * marked __initdata will be discarded when the module has been initialized.
1896 * Likewise for modules used built-in the sections marked __exit
1897 * are discarded because __exit marked function are supposed to be called
1898 * only when a module is unloaded which never happens for built-in modules.
1899 * The check_sec_ref() function traverses all relocation records
1900 * to find all references to a section that reference a section that will
1901 * be discarded and warns about it.
1903 static void check_sec_ref(struct module *mod, const char *modname,
1904 struct elf_info *elf)
1907 Elf_Shdr *sechdrs = elf->sechdrs;
1909 /* Walk through all sections */
1910 for (i = 0; i < elf->num_sections; i++) {
1911 check_section(modname, elf, &elf->sechdrs[i]);
1912 /* We want to process only relocation sections and not .init */
1913 if (sechdrs[i].sh_type == SHT_RELA)
1914 section_rela(modname, elf, &elf->sechdrs[i]);
1915 else if (sechdrs[i].sh_type == SHT_REL)
1916 section_rel(modname, elf, &elf->sechdrs[i]);
1920 static char *remove_dot(char *s)
1922 size_t n = strcspn(s, ".");
1925 size_t m = strspn(s + n + 1, "0123456789");
1926 if (m && (s[n + m] == '.' || s[n + m] == 0))
1932 static void read_symbols(const char *modname)
1934 const char *symname;
1938 struct elf_info info = { };
1941 if (!parse_elf(&info, modname))
1944 mod = new_module(modname);
1946 /* When there's no vmlinux, don't print warnings about
1947 * unresolved symbols (since there'll be too many ;) */
1948 if (is_vmlinux(modname)) {
1953 license = get_modinfo(&info, "license");
1954 if (!license && !is_vmlinux(modname))
1955 warn("modpost: missing MODULE_LICENSE() in %s\n"
1956 "see include/linux/module.h for "
1957 "more information\n", modname);
1959 if (license_is_gpl_compatible(license))
1960 mod->gpl_compatible = 1;
1962 mod->gpl_compatible = 0;
1965 license = get_next_modinfo(&info, "license", license);
1968 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1969 symname = remove_dot(info.strtab + sym->st_name);
1971 handle_modversions(mod, &info, sym, symname);
1972 handle_moddevtable(mod, &info, sym, symname);
1974 if (!is_vmlinux(modname) || vmlinux_section_warnings)
1975 check_sec_ref(mod, modname, &info);
1977 version = get_modinfo(&info, "version");
1979 maybe_frob_rcs_version(modname, version, info.modinfo,
1980 version - (char *)info.hdr);
1981 if (version || (all_versions && !is_vmlinux(modname)))
1982 get_src_version(modname, mod->srcversion,
1983 sizeof(mod->srcversion)-1);
1985 parse_elf_finish(&info);
1987 /* Our trick to get versioning for module struct etc. - it's
1988 * never passed as an argument to an exported function, so
1989 * the automatic versioning doesn't pick it up, but it's really
1990 * important anyhow */
1992 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1995 static void read_symbols_from_files(const char *filename)
1998 char fname[PATH_MAX];
2000 if (strcmp(filename, "-") != 0) {
2001 in = fopen(filename, "r");
2003 fatal("Can't open filenames file %s: %m", filename);
2006 while (fgets(fname, PATH_MAX, in) != NULL) {
2007 if (strends(fname, "\n"))
2008 fname[strlen(fname)-1] = '\0';
2009 read_symbols(fname);
2018 /* We first write the generated file into memory using the
2019 * following helper, then compare to the file on disk and
2020 * only update the later if anything changed */
2022 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2023 const char *fmt, ...)
2030 len = vsnprintf(tmp, SZ, fmt, ap);
2031 buf_write(buf, tmp, len);
2035 void buf_write(struct buffer *buf, const char *s, int len)
2037 if (buf->size - buf->pos < len) {
2038 buf->size += len + SZ;
2039 buf->p = NOFAIL(realloc(buf->p, buf->size));
2041 strncpy(buf->p + buf->pos, s, len);
2045 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2047 const char *e = is_vmlinux(m) ?"":".ko";
2051 fatal("modpost: GPL-incompatible module %s%s "
2052 "uses GPL-only symbol '%s'\n", m, e, s);
2054 case export_unused_gpl:
2055 fatal("modpost: GPL-incompatible module %s%s "
2056 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2058 case export_gpl_future:
2059 warn("modpost: GPL-incompatible module %s%s "
2060 "uses future GPL-only symbol '%s'\n", m, e, s);
2064 case export_unknown:
2070 static void check_for_unused(enum export exp, const char *m, const char *s)
2072 const char *e = is_vmlinux(m) ?"":".ko";
2076 case export_unused_gpl:
2077 warn("modpost: module %s%s "
2078 "uses symbol '%s' marked UNUSED\n", m, e, s);
2086 static void check_exports(struct module *mod)
2088 struct symbol *s, *exp;
2090 for (s = mod->unres; s; s = s->next) {
2091 const char *basename;
2092 exp = find_symbol(s->name);
2093 if (!exp || exp->module == mod)
2095 basename = strrchr(mod->name, '/');
2099 basename = mod->name;
2100 if (!mod->gpl_compatible)
2101 check_for_gpl_usage(exp->export, basename, exp->name);
2102 check_for_unused(exp->export, basename, exp->name);
2106 static int check_modname_len(struct module *mod)
2108 const char *mod_name;
2110 mod_name = strrchr(mod->name, '/');
2111 if (mod_name == NULL)
2112 mod_name = mod->name;
2115 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2116 merror("module name is too long [%s.ko]\n", mod->name);
2124 * Header for the generated file
2126 static void add_header(struct buffer *b, struct module *mod)
2128 buf_printf(b, "#include <linux/build-salt.h>\n");
2129 buf_printf(b, "#include <linux/module.h>\n");
2130 buf_printf(b, "#include <linux/vermagic.h>\n");
2131 buf_printf(b, "#include <linux/compiler.h>\n");
2132 buf_printf(b, "\n");
2133 buf_printf(b, "BUILD_SALT;\n");
2134 buf_printf(b, "\n");
2135 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2136 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2137 buf_printf(b, "\n");
2138 buf_printf(b, "__visible struct module __this_module\n");
2139 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2140 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2142 buf_printf(b, "\t.init = init_module,\n");
2143 if (mod->has_cleanup)
2144 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2145 "\t.exit = cleanup_module,\n"
2147 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2148 buf_printf(b, "};\n");
2151 static void add_intree_flag(struct buffer *b, int is_intree)
2154 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2157 /* Cannot check for assembler */
2158 static void add_retpoline(struct buffer *b)
2160 buf_printf(b, "\n#ifdef RETPOLINE\n");
2161 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2162 buf_printf(b, "#endif\n");
2165 static void add_staging_flag(struct buffer *b, const char *name)
2167 if (strstarts(name, "drivers/staging"))
2168 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2172 * Record CRCs for unresolved symbols
2174 static int add_versions(struct buffer *b, struct module *mod)
2176 struct symbol *s, *exp;
2179 for (s = mod->unres; s; s = s->next) {
2180 exp = find_symbol(s->name);
2181 if (!exp || exp->module == mod) {
2182 if (have_vmlinux && !s->weak) {
2183 if (warn_unresolved) {
2184 warn("\"%s\" [%s.ko] undefined!\n",
2185 s->name, mod->name);
2187 merror("\"%s\" [%s.ko] undefined!\n",
2188 s->name, mod->name);
2194 s->module = exp->module;
2195 s->crc_valid = exp->crc_valid;
2202 buf_printf(b, "\n");
2203 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2204 buf_printf(b, "__used\n");
2205 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2207 for (s = mod->unres; s; s = s->next) {
2210 if (!s->crc_valid) {
2211 warn("\"%s\" [%s.ko] has no CRC!\n",
2212 s->name, mod->name);
2215 if (strlen(s->name) >= MODULE_NAME_LEN) {
2216 merror("too long symbol \"%s\" [%s.ko]\n",
2217 s->name, mod->name);
2221 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2225 buf_printf(b, "};\n");
2230 static void add_depends(struct buffer *b, struct module *mod,
2231 struct module *modules)
2237 for (m = modules; m; m = m->next)
2238 m->seen = is_vmlinux(m->name);
2240 buf_printf(b, "\n");
2241 buf_printf(b, "static const char __module_depends[]\n");
2242 buf_printf(b, "__used\n");
2243 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2244 buf_printf(b, "\"depends=");
2245 for (s = mod->unres; s; s = s->next) {
2250 if (s->module->seen)
2253 s->module->seen = 1;
2254 p = strrchr(s->module->name, '/');
2258 p = s->module->name;
2259 buf_printf(b, "%s%s", first ? "" : ",", p);
2262 buf_printf(b, "\";\n");
2265 static void add_srcversion(struct buffer *b, struct module *mod)
2267 if (mod->srcversion[0]) {
2268 buf_printf(b, "\n");
2269 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2274 static void write_if_changed(struct buffer *b, const char *fname)
2280 file = fopen(fname, "r");
2284 if (fstat(fileno(file), &st) < 0)
2287 if (st.st_size != b->pos)
2290 tmp = NOFAIL(malloc(b->pos));
2291 if (fread(tmp, 1, b->pos, file) != b->pos)
2294 if (memcmp(tmp, b->p, b->pos) != 0)
2306 file = fopen(fname, "w");
2311 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2318 /* parse Module.symvers file. line format:
2319 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2321 static void read_dump(const char *fname, unsigned int kernel)
2323 unsigned long size, pos = 0;
2324 void *file = grab_file(fname, &size);
2328 /* No symbol versions, silently ignore */
2331 while ((line = get_next_line(&pos, file, size))) {
2332 char *symname, *modname, *d, *export, *end;
2337 if (!(symname = strchr(line, '\t')))
2340 if (!(modname = strchr(symname, '\t')))
2343 if ((export = strchr(modname, '\t')) != NULL)
2345 if (export && ((end = strchr(export, '\t')) != NULL))
2347 crc = strtoul(line, &d, 16);
2348 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2350 mod = find_module(modname);
2352 if (is_vmlinux(modname))
2354 mod = new_module(modname);
2357 s = sym_add_exported(symname, mod, export_no(export));
2360 sym_update_crc(symname, mod, crc, export_no(export));
2362 release_file(file, size);
2365 release_file(file, size);
2366 fatal("parse error in symbol dump file\n");
2369 /* For normal builds always dump all symbols.
2370 * For external modules only dump symbols
2371 * that are not read from kernel Module.symvers.
2373 static int dump_sym(struct symbol *sym)
2375 if (!external_module)
2377 if (sym->vmlinux || sym->kernel)
2382 static void write_dump(const char *fname)
2384 struct buffer buf = { };
2385 struct symbol *symbol;
2388 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2389 symbol = symbolhash[n];
2391 if (dump_sym(symbol))
2392 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2393 symbol->crc, symbol->name,
2394 symbol->module->name,
2395 export_str(symbol->export));
2396 symbol = symbol->next;
2399 write_if_changed(&buf, fname);
2403 struct ext_sym_list {
2404 struct ext_sym_list *next;
2408 int main(int argc, char **argv)
2411 struct buffer buf = { };
2412 char *kernel_read = NULL, *module_read = NULL;
2413 char *dump_write = NULL, *files_source = NULL;
2416 struct ext_sym_list *extsym_iter;
2417 struct ext_sym_list *extsym_start = NULL;
2419 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2422 kernel_read = optarg;
2425 module_read = optarg;
2426 external_module = 1;
2429 external_module = 1;
2431 NOFAIL(malloc(sizeof(*extsym_iter)));
2432 extsym_iter->next = extsym_start;
2433 extsym_iter->file = optarg;
2434 extsym_start = extsym_iter;
2440 ignore_missing_files = 1;
2443 dump_write = optarg;
2449 vmlinux_section_warnings = 0;
2452 sec_mismatch_verbose = 0;
2455 files_source = optarg;
2458 warn_unresolved = 1;
2461 sec_mismatch_fatal = 1;
2469 read_dump(kernel_read, 1);
2471 read_dump(module_read, 0);
2472 while (extsym_start) {
2473 read_dump(extsym_start->file, 0);
2474 extsym_iter = extsym_start->next;
2476 extsym_start = extsym_iter;
2479 while (optind < argc)
2480 read_symbols(argv[optind++]);
2483 read_symbols_from_files(files_source);
2485 for (mod = modules; mod; mod = mod->next) {
2493 for (mod = modules; mod; mod = mod->next) {
2494 char fname[PATH_MAX];
2501 err |= check_modname_len(mod);
2502 add_header(&buf, mod);
2503 add_intree_flag(&buf, !external_module);
2504 add_retpoline(&buf);
2505 add_staging_flag(&buf, mod->name);
2506 err |= add_versions(&buf, mod);
2507 add_depends(&buf, mod, modules);
2508 add_moddevtable(&buf, mod);
2509 add_srcversion(&buf, mod);
2511 sprintf(fname, "%s.mod.c", mod->name);
2512 write_if_changed(&buf, fname);
2515 write_dump(dump_write);
2516 if (sec_mismatch_count) {
2517 if (!sec_mismatch_verbose) {
2518 warn("modpost: Found %d section mismatch(es).\n"
2519 "To see full details build your kernel with:\n"
2520 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2521 sec_mismatch_count);
2523 if (sec_mismatch_fatal) {
2524 fatal("modpost: Section mismatches detected.\n"
2525 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");