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 ...
19 #include "../../include/generated/autoconf.h"
20 #include "../../include/linux/license.h"
22 /* Some toolchains use a `_' prefix for all user symbols. */
23 #ifdef CONFIG_SYMBOL_PREFIX
24 #define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
26 #define MODULE_SYMBOL_PREFIX ""
30 /* Are we using CONFIG_MODVERSIONS? */
31 static int modversions = 0;
32 /* Warn about undefined symbols? (do so if we have vmlinux) */
33 static int have_vmlinux = 0;
34 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
35 static int all_versions = 0;
36 /* If we are modposting external module set to 1 */
37 static int external_module = 0;
38 /* Warn about section mismatch in vmlinux if set to 1 */
39 static int vmlinux_section_warnings = 1;
40 /* Only warn about unresolved symbols */
41 static int warn_unresolved = 0;
42 /* How a symbol is exported */
43 static int sec_mismatch_count = 0;
44 static int sec_mismatch_verbose = 1;
47 export_plain, export_unused, export_gpl,
48 export_unused_gpl, export_gpl_future, export_unknown
51 #define PRINTF __attribute__ ((format (printf, 1, 2)))
53 PRINTF void fatal(const char *fmt, ...)
57 fprintf(stderr, "FATAL: ");
59 va_start(arglist, fmt);
60 vfprintf(stderr, fmt, arglist);
66 PRINTF void warn(const char *fmt, ...)
70 fprintf(stderr, "WARNING: ");
72 va_start(arglist, fmt);
73 vfprintf(stderr, fmt, arglist);
77 PRINTF void merror(const char *fmt, ...)
81 fprintf(stderr, "ERROR: ");
83 va_start(arglist, fmt);
84 vfprintf(stderr, fmt, arglist);
88 static int is_vmlinux(const char *modname)
92 myname = strrchr(modname, '/');
98 return (strcmp(myname, "vmlinux") == 0) ||
99 (strcmp(myname, "vmlinux.o") == 0);
102 void *do_nofail(void *ptr, const char *expr)
105 fatal("modpost: Memory allocation failure: %s.\n", expr);
110 /* A list of all modules we processed */
111 static struct module *modules;
113 static struct module *find_module(char *modname)
117 for (mod = modules; mod; mod = mod->next)
118 if (strcmp(mod->name, modname) == 0)
123 static struct module *new_module(char *modname)
128 mod = NOFAIL(malloc(sizeof(*mod)));
129 memset(mod, 0, sizeof(*mod));
130 p = NOFAIL(strdup(modname));
132 /* strip trailing .o */
135 if (strcmp(s, ".o") == 0) {
142 mod->gpl_compatible = -1;
149 /* A hash of all exported symbols,
150 * struct symbol is also used for lists of unresolved symbols */
152 #define SYMBOL_HASH_SIZE 1024
156 struct module *module;
160 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
161 unsigned int kernel:1; /* 1 if symbol is from kernel
162 * (only for external modules) **/
163 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
164 enum export export; /* Type of export */
168 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
170 /* This is based on the hash agorithm from gdbm, via tdb */
171 static inline unsigned int tdb_hash(const char *name)
173 unsigned value; /* Used to compute the hash value. */
174 unsigned i; /* Used to cycle through random values. */
176 /* Set the initial value from the key size. */
177 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
178 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
180 return (1103515243 * value + 12345);
184 * Allocate a new symbols for use in the hash of exported symbols or
185 * the list of unresolved symbols per module
187 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
190 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
192 memset(s, 0, sizeof(*s));
193 strcpy(s->name, name);
199 /* For the hash of exported symbols */
200 static struct symbol *new_symbol(const char *name, struct module *module,
206 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
207 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
208 new->module = module;
209 new->export = export;
213 static struct symbol *find_symbol(const char *name)
217 /* For our purposes, .foo matches foo. PPC64 needs this. */
221 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
222 if (strcmp(s->name, name) == 0)
228 static const struct {
232 { .str = "EXPORT_SYMBOL", .export = export_plain },
233 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
234 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
235 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
236 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
237 { .str = "(unknown)", .export = export_unknown },
241 static const char *export_str(enum export ex)
243 return export_list[ex].str;
246 static enum export export_no(const char *s)
251 return export_unknown;
252 for (i = 0; export_list[i].export != export_unknown; i++) {
253 if (strcmp(export_list[i].str, s) == 0)
254 return export_list[i].export;
256 return export_unknown;
259 static const char *sec_name(struct elf_info *elf, int secindex);
261 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
263 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
265 const char *secname = sec_name(elf, sec);
267 if (strstarts(secname, "___ksymtab+"))
269 else if (strstarts(secname, "___ksymtab_unused+"))
270 return export_unused;
271 else if (strstarts(secname, "___ksymtab_gpl+"))
273 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
274 return export_unused_gpl;
275 else if (strstarts(secname, "___ksymtab_gpl_future+"))
276 return export_gpl_future;
278 return export_unknown;
281 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
283 if (sec == elf->export_sec)
285 else if (sec == elf->export_unused_sec)
286 return export_unused;
287 else if (sec == elf->export_gpl_sec)
289 else if (sec == elf->export_unused_gpl_sec)
290 return export_unused_gpl;
291 else if (sec == elf->export_gpl_future_sec)
292 return export_gpl_future;
294 return export_unknown;
298 * Add an exported symbol - it may have already been added without a
299 * CRC, in this case just update the CRC
301 static struct symbol *sym_add_exported(const char *name, struct module *mod,
304 struct symbol *s = find_symbol(name);
307 s = new_symbol(name, mod, export);
310 warn("%s: '%s' exported twice. Previous export "
311 "was in %s%s\n", mod->name, name,
313 is_vmlinux(s->module->name) ?"":".ko");
315 /* In case Modules.symvers was out of date */
320 s->vmlinux = is_vmlinux(mod->name);
326 static void sym_update_crc(const char *name, struct module *mod,
327 unsigned int crc, enum export export)
329 struct symbol *s = find_symbol(name);
332 s = new_symbol(name, mod, export);
337 void *grab_file(const char *filename, unsigned long *size)
343 fd = open(filename, O_RDONLY);
344 if (fd < 0 || fstat(fd, &st) != 0)
348 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
351 if (map == MAP_FAILED)
357 * Return a copy of the next line in a mmap'ed file.
358 * spaces in the beginning of the line is trimmed away.
359 * Return a pointer to a static buffer.
361 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
363 static char line[4096];
366 signed char *p = (signed char *)file + *pos;
369 for (; *pos < size ; (*pos)++) {
370 if (skip && isspace(*p)) {
375 if (*p != '\n' && (*pos < size)) {
379 break; /* Too long, stop */
390 void release_file(void *file, unsigned long size)
395 static int parse_elf(struct elf_info *info, const char *filename)
401 const char *secstrings;
402 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
404 hdr = grab_file(filename, &info->size);
410 if (info->size < sizeof(*hdr)) {
411 /* file too small, assume this is an empty .o file */
414 /* Is this a valid ELF file? */
415 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
416 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
417 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
418 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
419 /* Not an ELF file - silently ignore it */
422 /* Fix endianness in ELF header */
423 hdr->e_type = TO_NATIVE(hdr->e_type);
424 hdr->e_machine = TO_NATIVE(hdr->e_machine);
425 hdr->e_version = TO_NATIVE(hdr->e_version);
426 hdr->e_entry = TO_NATIVE(hdr->e_entry);
427 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
428 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
429 hdr->e_flags = TO_NATIVE(hdr->e_flags);
430 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
431 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
432 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
433 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
434 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
435 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
436 sechdrs = (void *)hdr + hdr->e_shoff;
437 info->sechdrs = sechdrs;
439 /* Check if file offset is correct */
440 if (hdr->e_shoff > info->size) {
441 fatal("section header offset=%lu in file '%s' is bigger than "
442 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
443 filename, info->size);
447 if (hdr->e_shnum == SHN_UNDEF) {
449 * There are more than 64k sections,
450 * read count from .sh_size.
452 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
455 info->num_sections = hdr->e_shnum;
457 if (hdr->e_shstrndx == SHN_XINDEX) {
458 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
461 info->secindex_strings = hdr->e_shstrndx;
464 /* Fix endianness in section headers */
465 for (i = 0; i < info->num_sections; i++) {
466 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
467 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
468 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
469 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
470 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
471 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
472 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
473 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
474 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
475 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
477 /* Find symbol table. */
478 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
479 for (i = 1; i < info->num_sections; i++) {
481 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
483 if (!nobits && sechdrs[i].sh_offset > info->size) {
484 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
485 "sizeof(*hrd)=%zu\n", filename,
486 (unsigned long)sechdrs[i].sh_offset,
490 secname = secstrings + sechdrs[i].sh_name;
491 if (strcmp(secname, ".modinfo") == 0) {
493 fatal("%s has NOBITS .modinfo\n", filename);
494 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
495 info->modinfo_len = sechdrs[i].sh_size;
496 } else if (strcmp(secname, "__ksymtab") == 0)
497 info->export_sec = i;
498 else if (strcmp(secname, "__ksymtab_unused") == 0)
499 info->export_unused_sec = i;
500 else if (strcmp(secname, "__ksymtab_gpl") == 0)
501 info->export_gpl_sec = i;
502 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
503 info->export_unused_gpl_sec = i;
504 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
505 info->export_gpl_future_sec = i;
507 if (sechdrs[i].sh_type == SHT_SYMTAB) {
508 unsigned int sh_link_idx;
510 info->symtab_start = (void *)hdr +
511 sechdrs[i].sh_offset;
512 info->symtab_stop = (void *)hdr +
513 sechdrs[i].sh_offset + sechdrs[i].sh_size;
514 sh_link_idx = sechdrs[i].sh_link;
515 info->strtab = (void *)hdr +
516 sechdrs[sh_link_idx].sh_offset;
519 /* 32bit section no. table? ("more than 64k sections") */
520 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
521 symtab_shndx_idx = i;
522 info->symtab_shndx_start = (void *)hdr +
523 sechdrs[i].sh_offset;
524 info->symtab_shndx_stop = (void *)hdr +
525 sechdrs[i].sh_offset + sechdrs[i].sh_size;
528 if (!info->symtab_start)
529 fatal("%s has no symtab?\n", filename);
531 /* Fix endianness in symbols */
532 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
533 sym->st_shndx = TO_NATIVE(sym->st_shndx);
534 sym->st_name = TO_NATIVE(sym->st_name);
535 sym->st_value = TO_NATIVE(sym->st_value);
536 sym->st_size = TO_NATIVE(sym->st_size);
539 if (symtab_shndx_idx != ~0U) {
541 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
542 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
543 filename, sechdrs[symtab_shndx_idx].sh_link,
546 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
554 static void parse_elf_finish(struct elf_info *info)
556 release_file(info->hdr, info->size);
559 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
561 /* ignore __this_module, it will be resolved shortly */
562 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
564 /* ignore global offset table */
565 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
567 if (info->hdr->e_machine == EM_PPC)
568 /* Special register function linked on all modules during final link of .ko */
569 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
570 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
571 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
572 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
573 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
574 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
576 if (info->hdr->e_machine == EM_PPC64)
577 /* Special register function linked on all modules during final link of .ko */
578 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
579 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
580 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
581 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
583 /* Do not ignore this symbol */
587 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
588 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
590 static void handle_modversions(struct module *mod, struct elf_info *info,
591 Elf_Sym *sym, const char *symname)
596 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
597 strncmp(symname, "__ksymtab", 9) == 0)
598 export = export_from_secname(info, get_secindex(info, sym));
600 export = export_from_sec(info, get_secindex(info, sym));
602 switch (sym->st_shndx) {
604 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
608 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
609 crc = (unsigned int) sym->st_value;
610 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
615 /* undefined symbol */
616 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
617 ELF_ST_BIND(sym->st_info) != STB_WEAK)
619 if (ignore_undef_symbol(info, symname))
621 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
622 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
623 /* add compatibility with older glibc */
624 #ifndef STT_SPARC_REGISTER
625 #define STT_SPARC_REGISTER STT_REGISTER
627 if (info->hdr->e_machine == EM_SPARC ||
628 info->hdr->e_machine == EM_SPARCV9) {
629 /* Ignore register directives. */
630 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
632 if (symname[0] == '.') {
633 char *munged = strdup(symname);
635 munged[1] = toupper(munged[1]);
641 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
642 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
644 alloc_symbol(symname +
645 strlen(MODULE_SYMBOL_PREFIX),
646 ELF_ST_BIND(sym->st_info) == STB_WEAK,
651 /* All exported symbols */
652 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
653 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
656 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
658 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
659 mod->has_cleanup = 1;
665 * Parse tag=value strings from .modinfo section
667 static char *next_string(char *string, unsigned long *secsize)
669 /* Skip non-zero chars */
672 if ((*secsize)-- <= 1)
676 /* Skip any zero padding. */
679 if ((*secsize)-- <= 1)
685 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
686 const char *tag, char *info)
689 unsigned int taglen = strlen(tag);
690 unsigned long size = modinfo_len;
693 size -= info - (char *)modinfo;
694 modinfo = next_string(info, &size);
697 for (p = modinfo; p; p = next_string(p, &size)) {
698 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
699 return p + taglen + 1;
704 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
708 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
712 * Test if string s ends in string sub
715 static int strrcmp(const char *s, const char *sub)
723 sublen = strlen(sub);
725 if ((slen == 0) || (sublen == 0))
731 return memcmp(s + slen - sublen, sub, sublen);
734 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
737 return elf->strtab + sym->st_name;
742 static const char *sec_name(struct elf_info *elf, int secindex)
744 Elf_Shdr *sechdrs = elf->sechdrs;
745 return (void *)elf->hdr +
746 elf->sechdrs[elf->secindex_strings].sh_offset +
747 sechdrs[secindex].sh_name;
750 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
752 return (void *)elf->hdr +
753 elf->sechdrs[elf->secindex_strings].sh_offset +
757 /* if sym is empty or point to a string
758 * like ".[0-9]+" then return 1.
759 * This is the optional prefix added by ld to some sections
761 static int number_prefix(const char *sym)
769 if (c < '0' || c > '9')
775 /* The pattern is an array of simple patterns.
776 * "foo" will match an exact string equal to "foo"
777 * "*foo" will match a string that ends with "foo"
778 * "foo*" will match a string that begins with "foo"
779 * "foo$" will match a string equal to "foo" or "foo.1"
780 * where the '1' can be any number including several digits.
781 * The $ syntax is for sections where ld append a dot number
782 * to make section name unique.
784 static int match(const char *sym, const char * const pat[])
789 const char *endp = p + strlen(p) - 1;
793 if (strrcmp(sym, p + 1) == 0)
797 else if (*endp == '*') {
798 if (strncmp(sym, p, strlen(p) - 1) == 0)
802 else if (*endp == '$') {
803 if (strncmp(sym, p, strlen(p) - 1) == 0) {
804 if (number_prefix(sym + strlen(p) - 1))
810 if (strcmp(p, sym) == 0)
818 /* sections that we do not want to do full section mismatch check on */
819 static const char *const section_white_list[] =
823 ".zdebug*", /* Compressed debug sections. */
824 ".GCC-command-line", /* mn10300 */
825 ".mdebug*", /* alpha, score, mips etc. */
826 ".pdr", /* alpha, score, mips etc. */
835 * This is used to find sections missing the SHF_ALLOC flag.
836 * The cause of this is often a section specified in assembler
837 * without "ax" / "aw".
839 static void check_section(const char *modname, struct elf_info *elf,
842 const char *sec = sech_name(elf, sechdr);
844 if (sechdr->sh_type == SHT_PROGBITS &&
845 !(sechdr->sh_flags & SHF_ALLOC) &&
846 !match(sec, section_white_list)) {
847 warn("%s (%s): unexpected non-allocatable section.\n"
848 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
849 "Note that for example <linux/init.h> contains\n"
850 "section definitions for use in .S files.\n\n",
857 #define ALL_INIT_DATA_SECTIONS \
858 ".init.setup$", ".init.rodata$", \
859 ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$", \
860 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
861 #define ALL_EXIT_DATA_SECTIONS \
862 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
864 #define ALL_INIT_TEXT_SECTIONS \
865 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
866 #define ALL_EXIT_TEXT_SECTIONS \
867 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
869 #define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
871 #define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
874 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
875 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
877 #define DATA_SECTIONS ".data$", ".data.rel$"
878 #define TEXT_SECTIONS ".text$"
879 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
880 ".fixup", ".entry.text"
882 #define INIT_SECTIONS ".init.*"
883 #define DEV_INIT_SECTIONS ".devinit.*"
884 #define CPU_INIT_SECTIONS ".cpuinit.*"
885 #define MEM_INIT_SECTIONS ".meminit.*"
887 #define EXIT_SECTIONS ".exit.*"
888 #define DEV_EXIT_SECTIONS ".devexit.*"
889 #define CPU_EXIT_SECTIONS ".cpuexit.*"
890 #define MEM_EXIT_SECTIONS ".memexit.*"
892 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
893 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
895 /* init data sections */
896 static const char *const init_data_sections[] =
897 { ALL_INIT_DATA_SECTIONS, NULL };
899 /* all init sections */
900 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
902 /* All init and exit sections (code + data) */
903 static const char *const init_exit_sections[] =
904 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
906 /* all text sections */
907 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
910 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
913 /* symbols in .data that may refer to init/exit sections */
914 #define DEFAULT_SYMBOL_WHITE_LIST \
916 "*_template", /* scsi uses *_template a lot */ \
917 "*_timer", /* arm uses ops structures named _timer a lot */ \
918 "*_sht", /* scsi also used *_sht to some extent */ \
924 static const char *const head_sections[] = { ".head.text*", NULL };
925 static const char *const linker_symbols[] =
926 { "__init_begin", "_sinittext", "_einittext", NULL };
927 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
934 XXXINIT_TO_SOME_INIT,
935 XXXEXIT_TO_SOME_EXIT,
936 ANY_INIT_TO_ANY_EXIT,
937 ANY_EXIT_TO_ANY_INIT,
941 struct sectioncheck {
942 const char *fromsec[20];
943 const char *tosec[20];
944 enum mismatch mismatch;
945 const char *symbol_white_list[20];
948 static const struct sectioncheck sectioncheck[] = {
949 /* Do not reference init/exit code/data from
950 * normal code and data
953 .fromsec = { TEXT_SECTIONS, NULL },
954 .tosec = { ALL_INIT_SECTIONS, NULL },
955 .mismatch = TEXT_TO_ANY_INIT,
956 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
959 .fromsec = { DATA_SECTIONS, NULL },
960 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
961 .mismatch = DATA_TO_ANY_INIT,
962 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
965 .fromsec = { DATA_SECTIONS, NULL },
966 .tosec = { INIT_SECTIONS, NULL },
967 .mismatch = DATA_TO_ANY_INIT,
968 .symbol_white_list = {
969 "*_template", "*_timer", "*_sht", "*_ops",
970 "*_probe", "*_probe_one", "*_console", NULL
974 .fromsec = { TEXT_SECTIONS, NULL },
975 .tosec = { ALL_EXIT_SECTIONS, NULL },
976 .mismatch = TEXT_TO_ANY_EXIT,
977 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
980 .fromsec = { DATA_SECTIONS, NULL },
981 .tosec = { ALL_EXIT_SECTIONS, NULL },
982 .mismatch = DATA_TO_ANY_EXIT,
983 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
985 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */
987 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
988 .tosec = { INIT_SECTIONS, NULL },
989 .mismatch = XXXINIT_TO_SOME_INIT,
990 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
992 /* Do not reference cpuinit code/data from meminit code/data */
994 .fromsec = { MEM_INIT_SECTIONS, NULL },
995 .tosec = { CPU_INIT_SECTIONS, NULL },
996 .mismatch = XXXINIT_TO_SOME_INIT,
997 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
999 /* Do not reference meminit code/data from cpuinit code/data */
1001 .fromsec = { CPU_INIT_SECTIONS, NULL },
1002 .tosec = { MEM_INIT_SECTIONS, NULL },
1003 .mismatch = XXXINIT_TO_SOME_INIT,
1004 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1006 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
1008 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1009 .tosec = { EXIT_SECTIONS, NULL },
1010 .mismatch = XXXEXIT_TO_SOME_EXIT,
1011 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1013 /* Do not reference cpuexit code/data from memexit code/data */
1015 .fromsec = { MEM_EXIT_SECTIONS, NULL },
1016 .tosec = { CPU_EXIT_SECTIONS, NULL },
1017 .mismatch = XXXEXIT_TO_SOME_EXIT,
1018 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1020 /* Do not reference memexit code/data from cpuexit code/data */
1022 .fromsec = { CPU_EXIT_SECTIONS, NULL },
1023 .tosec = { MEM_EXIT_SECTIONS, NULL },
1024 .mismatch = XXXEXIT_TO_SOME_EXIT,
1025 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1027 /* Do not use exit code/data from init code */
1029 .fromsec = { ALL_INIT_SECTIONS, NULL },
1030 .tosec = { ALL_EXIT_SECTIONS, NULL },
1031 .mismatch = ANY_INIT_TO_ANY_EXIT,
1032 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1034 /* Do not use init code/data from exit code */
1036 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1037 .tosec = { ALL_INIT_SECTIONS, NULL },
1038 .mismatch = ANY_EXIT_TO_ANY_INIT,
1039 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1041 /* Do not export init/exit functions or data */
1043 .fromsec = { "__ksymtab*", NULL },
1044 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1045 .mismatch = EXPORT_TO_INIT_EXIT,
1046 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1050 static const struct sectioncheck *section_mismatch(
1051 const char *fromsec, const char *tosec)
1054 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1055 const struct sectioncheck *check = §ioncheck[0];
1057 for (i = 0; i < elems; i++) {
1058 if (match(fromsec, check->fromsec) &&
1059 match(tosec, check->tosec))
1067 * Whitelist to allow certain references to pass with no warning.
1070 * If a module parameter is declared __initdata and permissions=0
1071 * then this is legal despite the warning generated.
1072 * We cannot see value of permissions here, so just ignore
1074 * The pattern is identified by:
1075 * tosec = .init.data
1080 * module_param_call() ops can refer to __init set function if permissions=0
1081 * The pattern is identified by:
1082 * tosec = .init.text
1084 * atsym = __param_ops_*
1087 * Many drivers utilise a *driver container with references to
1088 * add, remove, probe functions etc.
1089 * These functions may often be marked __devinit and we do not want to
1091 * the pattern is identified by:
1092 * tosec = init or exit section
1093 * fromsec = data section
1094 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1095 * *probe_one, *_console, *_timer
1098 * Whitelist all references from .head.text to any init section
1101 * Some symbols belong to init section but still it is ok to reference
1102 * these from non-init sections as these symbols don't have any memory
1103 * allocated for them and symbol address and value are same. So even
1104 * if init section is freed, its ok to reference those symbols.
1105 * For ex. symbols marking the init section boundaries.
1106 * This pattern is identified by
1107 * refsymname = __init_begin, _sinittext, _einittext
1110 * GCC may optimize static inlines when fed constant arg(s) resulting
1111 * in functions like cpumask_empty() -- generating an associated symbol
1112 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1113 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1114 * meaningless section warning. May need to add isra symbols too...
1115 * This pattern is identified by
1116 * tosec = init section
1117 * fromsec = text section
1118 * refsymname = *.constprop.*
1121 static int secref_whitelist(const struct sectioncheck *mismatch,
1122 const char *fromsec, const char *fromsym,
1123 const char *tosec, const char *tosym)
1125 /* Check for pattern 1 */
1126 if (match(tosec, init_data_sections) &&
1127 match(fromsec, data_sections) &&
1128 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1131 /* Check for pattern 1a */
1132 if (strcmp(tosec, ".init.text") == 0 &&
1133 match(fromsec, data_sections) &&
1134 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1137 /* Check for pattern 2 */
1138 if (match(tosec, init_exit_sections) &&
1139 match(fromsec, data_sections) &&
1140 match(fromsym, mismatch->symbol_white_list))
1143 /* Check for pattern 3 */
1144 if (match(fromsec, head_sections) &&
1145 match(tosec, init_sections))
1148 /* Check for pattern 4 */
1149 if (match(tosym, linker_symbols))
1152 /* Check for pattern 5 */
1153 if (match(fromsec, text_sections) &&
1154 match(tosec, init_sections) &&
1155 match(fromsym, optim_symbols))
1162 * Find symbol based on relocation record info.
1163 * In some cases the symbol supplied is a valid symbol so
1164 * return refsym. If st_name != 0 we assume this is a valid symbol.
1165 * In other cases the symbol needs to be looked up in the symbol table
1166 * based on section and address.
1168 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1172 Elf_Sym *near = NULL;
1173 Elf64_Sword distance = 20;
1175 unsigned int relsym_secindex;
1177 if (relsym->st_name != 0)
1180 relsym_secindex = get_secindex(elf, relsym);
1181 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1182 if (get_secindex(elf, sym) != relsym_secindex)
1184 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1186 if (sym->st_value == addr)
1188 /* Find a symbol nearby - addr are maybe negative */
1189 d = sym->st_value - addr;
1191 d = addr - sym->st_value;
1197 /* We need a close match */
1204 static inline int is_arm_mapping_symbol(const char *str)
1206 return str[0] == '$' && strchr("atd", str[1])
1207 && (str[2] == '\0' || str[2] == '.');
1211 * If there's no name there, ignore it; likewise, ignore it if it's
1212 * one of the magic symbols emitted used by current ARM tools.
1214 * Otherwise if find_symbols_between() returns those symbols, they'll
1215 * fail the whitelist tests and cause lots of false alarms ... fixable
1216 * only by merging __exit and __init sections into __text, bloating
1217 * the kernel (which is especially evil on embedded platforms).
1219 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1221 const char *name = elf->strtab + sym->st_name;
1223 if (!name || !strlen(name))
1225 return !is_arm_mapping_symbol(name);
1229 * Find symbols before or equal addr and after addr - in the section sec.
1230 * If we find two symbols with equal offset prefer one with a valid name.
1231 * The ELF format may have a better way to detect what type of symbol
1232 * it is, but this works for now.
1234 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1238 Elf_Sym *near = NULL;
1239 Elf_Addr distance = ~0;
1241 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1244 if (is_shndx_special(sym->st_shndx))
1246 symsec = sec_name(elf, get_secindex(elf, sym));
1247 if (strcmp(symsec, sec) != 0)
1249 if (!is_valid_name(elf, sym))
1251 if (sym->st_value <= addr) {
1252 if ((addr - sym->st_value) < distance) {
1253 distance = addr - sym->st_value;
1255 } else if ((addr - sym->st_value) == distance) {
1264 * Convert a section name to the function/data attribute
1265 * .init.text => __init
1266 * .cpuinit.data => __cpudata
1267 * .memexitconst => __memconst
1270 * The memory of returned value has been allocated on a heap. The user of this
1271 * method should free it after usage.
1273 static char *sec2annotation(const char *s)
1275 if (match(s, init_exit_sections)) {
1276 char *p = malloc(20);
1283 while (*s && *s != '.')
1288 if (strstr(s, "rodata") != NULL)
1289 strcat(p, "const ");
1290 else if (strstr(s, "data") != NULL)
1300 static int is_function(Elf_Sym *sym)
1303 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1308 static void print_section_list(const char * const list[20])
1310 const char *const *s = list;
1313 fprintf(stderr, "%s", *s);
1316 fprintf(stderr, ", ");
1318 fprintf(stderr, "\n");
1322 * Print a warning about a section mismatch.
1323 * Try to find symbols near it so user can find it.
1324 * Check whitelist before warning - it may be a false positive.
1326 static void report_sec_mismatch(const char *modname,
1327 const struct sectioncheck *mismatch,
1328 const char *fromsec,
1329 unsigned long long fromaddr,
1330 const char *fromsym,
1332 const char *tosec, const char *tosym,
1335 const char *from, *from_p;
1336 const char *to, *to_p;
1340 switch (from_is_func) {
1341 case 0: from = "variable"; from_p = ""; break;
1342 case 1: from = "function"; from_p = "()"; break;
1343 default: from = "(unknown reference)"; from_p = ""; break;
1345 switch (to_is_func) {
1346 case 0: to = "variable"; to_p = ""; break;
1347 case 1: to = "function"; to_p = "()"; break;
1348 default: to = "(unknown reference)"; to_p = ""; break;
1351 sec_mismatch_count++;
1352 if (!sec_mismatch_verbose)
1355 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1356 "to the %s %s:%s%s\n",
1357 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1360 switch (mismatch->mismatch) {
1361 case TEXT_TO_ANY_INIT:
1362 prl_from = sec2annotation(fromsec);
1363 prl_to = sec2annotation(tosec);
1365 "The function %s%s() references\n"
1367 "This is often because %s lacks a %s\n"
1368 "annotation or the annotation of %s is wrong.\n",
1370 to, prl_to, tosym, to_p,
1371 fromsym, prl_to, tosym);
1375 case DATA_TO_ANY_INIT: {
1376 prl_to = sec2annotation(tosec);
1378 "The variable %s references\n"
1380 "If the reference is valid then annotate the\n"
1381 "variable with __init* or __refdata (see linux/init.h) "
1382 "or name the variable:\n",
1383 fromsym, to, prl_to, tosym, to_p);
1384 print_section_list(mismatch->symbol_white_list);
1388 case TEXT_TO_ANY_EXIT:
1389 prl_to = sec2annotation(tosec);
1391 "The function %s() references a %s in an exit section.\n"
1392 "Often the %s %s%s has valid usage outside the exit section\n"
1393 "and the fix is to remove the %sannotation of %s.\n",
1394 fromsym, to, to, tosym, to_p, prl_to, tosym);
1397 case DATA_TO_ANY_EXIT: {
1398 prl_to = sec2annotation(tosec);
1400 "The variable %s references\n"
1402 "If the reference is valid then annotate the\n"
1403 "variable with __exit* (see linux/init.h) or "
1404 "name the variable:\n",
1405 fromsym, to, prl_to, tosym, to_p);
1406 print_section_list(mismatch->symbol_white_list);
1410 case XXXINIT_TO_SOME_INIT:
1411 case XXXEXIT_TO_SOME_EXIT:
1412 prl_from = sec2annotation(fromsec);
1413 prl_to = sec2annotation(tosec);
1415 "The %s %s%s%s references\n"
1417 "If %s is only used by %s then\n"
1418 "annotate %s with a matching annotation.\n",
1419 from, prl_from, fromsym, from_p,
1420 to, prl_to, tosym, to_p,
1421 tosym, fromsym, tosym);
1425 case ANY_INIT_TO_ANY_EXIT:
1426 prl_from = sec2annotation(fromsec);
1427 prl_to = sec2annotation(tosec);
1429 "The %s %s%s%s references\n"
1431 "This is often seen when error handling "
1432 "in the init function\n"
1433 "uses functionality in the exit path.\n"
1434 "The fix is often to remove the %sannotation of\n"
1435 "%s%s so it may be used outside an exit section.\n",
1436 from, prl_from, fromsym, from_p,
1437 to, prl_to, tosym, to_p,
1438 prl_to, tosym, to_p);
1442 case ANY_EXIT_TO_ANY_INIT:
1443 prl_from = sec2annotation(fromsec);
1444 prl_to = sec2annotation(tosec);
1446 "The %s %s%s%s references\n"
1448 "This is often seen when error handling "
1449 "in the exit function\n"
1450 "uses functionality in the init path.\n"
1451 "The fix is often to remove the %sannotation of\n"
1452 "%s%s so it may be used outside an init section.\n",
1453 from, prl_from, fromsym, from_p,
1454 to, prl_to, tosym, to_p,
1455 prl_to, tosym, to_p);
1459 case EXPORT_TO_INIT_EXIT:
1460 prl_to = sec2annotation(tosec);
1462 "The symbol %s is exported and annotated %s\n"
1463 "Fix this by removing the %sannotation of %s "
1464 "or drop the export.\n",
1465 tosym, prl_to, prl_to, tosym);
1469 fprintf(stderr, "\n");
1472 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1473 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1476 const struct sectioncheck *mismatch;
1478 tosec = sec_name(elf, get_secindex(elf, sym));
1479 mismatch = section_mismatch(fromsec, tosec);
1484 const char *fromsym;
1486 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1487 fromsym = sym_name(elf, from);
1488 to = find_elf_symbol(elf, r->r_addend, sym);
1489 tosym = sym_name(elf, to);
1491 /* check whitelist - we may ignore it */
1492 if (secref_whitelist(mismatch,
1493 fromsec, fromsym, tosec, tosym)) {
1494 report_sec_mismatch(modname, mismatch,
1495 fromsec, r->r_offset, fromsym,
1496 is_function(from), tosec, tosym,
1502 static unsigned int *reloc_location(struct elf_info *elf,
1503 Elf_Shdr *sechdr, Elf_Rela *r)
1505 Elf_Shdr *sechdrs = elf->sechdrs;
1506 int section = sechdr->sh_info;
1508 return (void *)elf->hdr + sechdrs[section].sh_offset +
1512 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1514 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1515 unsigned int *location = reloc_location(elf, sechdr, r);
1519 r->r_addend = TO_NATIVE(*location);
1522 r->r_addend = TO_NATIVE(*location) + 4;
1523 /* For CONFIG_RELOCATABLE=y */
1524 if (elf->hdr->e_type == ET_EXEC)
1525 r->r_addend += r->r_offset;
1531 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1533 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1537 /* From ARM ABI: (S + A) | T */
1538 r->r_addend = (int)(long)
1539 (elf->symtab_start + ELF_R_SYM(r->r_info));
1542 /* From ARM ABI: ((S + A) | T) - P */
1543 r->r_addend = (int)(long)(elf->hdr +
1545 (r->r_offset - sechdr->sh_addr));
1553 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1555 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1556 unsigned int *location = reloc_location(elf, sechdr, r);
1559 if (r_typ == R_MIPS_HI16)
1560 return 1; /* skip this */
1561 inst = TO_NATIVE(*location);
1564 r->r_addend = inst & 0xffff;
1567 r->r_addend = (inst & 0x03ffffff) << 2;
1576 static void section_rela(const char *modname, struct elf_info *elf,
1583 const char *fromsec;
1585 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1586 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1588 fromsec = sech_name(elf, sechdr);
1589 fromsec += strlen(".rela");
1590 /* if from section (name) is know good then skip it */
1591 if (match(fromsec, section_white_list))
1594 for (rela = start; rela < stop; rela++) {
1595 r.r_offset = TO_NATIVE(rela->r_offset);
1596 #if KERNEL_ELFCLASS == ELFCLASS64
1597 if (elf->hdr->e_machine == EM_MIPS) {
1599 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1600 r_sym = TO_NATIVE(r_sym);
1601 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1602 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1604 r.r_info = TO_NATIVE(rela->r_info);
1605 r_sym = ELF_R_SYM(r.r_info);
1608 r.r_info = TO_NATIVE(rela->r_info);
1609 r_sym = ELF_R_SYM(r.r_info);
1611 r.r_addend = TO_NATIVE(rela->r_addend);
1612 sym = elf->symtab_start + r_sym;
1613 /* Skip special sections */
1614 if (is_shndx_special(sym->st_shndx))
1616 check_section_mismatch(modname, elf, &r, sym, fromsec);
1620 static void section_rel(const char *modname, struct elf_info *elf,
1627 const char *fromsec;
1629 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1630 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1632 fromsec = sech_name(elf, sechdr);
1633 fromsec += strlen(".rel");
1634 /* if from section (name) is know good then skip it */
1635 if (match(fromsec, section_white_list))
1638 for (rel = start; rel < stop; rel++) {
1639 r.r_offset = TO_NATIVE(rel->r_offset);
1640 #if KERNEL_ELFCLASS == ELFCLASS64
1641 if (elf->hdr->e_machine == EM_MIPS) {
1643 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1644 r_sym = TO_NATIVE(r_sym);
1645 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1646 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1648 r.r_info = TO_NATIVE(rel->r_info);
1649 r_sym = ELF_R_SYM(r.r_info);
1652 r.r_info = TO_NATIVE(rel->r_info);
1653 r_sym = ELF_R_SYM(r.r_info);
1656 switch (elf->hdr->e_machine) {
1658 if (addend_386_rel(elf, sechdr, &r))
1662 if (addend_arm_rel(elf, sechdr, &r))
1666 if (addend_mips_rel(elf, sechdr, &r))
1670 sym = elf->symtab_start + r_sym;
1671 /* Skip special sections */
1672 if (is_shndx_special(sym->st_shndx))
1674 check_section_mismatch(modname, elf, &r, sym, fromsec);
1679 * A module includes a number of sections that are discarded
1680 * either when loaded or when used as built-in.
1681 * For loaded modules all functions marked __init and all data
1682 * marked __initdata will be discarded when the module has been initialized.
1683 * Likewise for modules used built-in the sections marked __exit
1684 * are discarded because __exit marked function are supposed to be called
1685 * only when a module is unloaded which never happens for built-in modules.
1686 * The check_sec_ref() function traverses all relocation records
1687 * to find all references to a section that reference a section that will
1688 * be discarded and warns about it.
1690 static void check_sec_ref(struct module *mod, const char *modname,
1691 struct elf_info *elf)
1694 Elf_Shdr *sechdrs = elf->sechdrs;
1696 /* Walk through all sections */
1697 for (i = 0; i < elf->num_sections; i++) {
1698 check_section(modname, elf, &elf->sechdrs[i]);
1699 /* We want to process only relocation sections and not .init */
1700 if (sechdrs[i].sh_type == SHT_RELA)
1701 section_rela(modname, elf, &elf->sechdrs[i]);
1702 else if (sechdrs[i].sh_type == SHT_REL)
1703 section_rel(modname, elf, &elf->sechdrs[i]);
1707 static void read_symbols(char *modname)
1709 const char *symname;
1713 struct elf_info info = { };
1716 if (!parse_elf(&info, modname))
1719 mod = new_module(modname);
1721 /* When there's no vmlinux, don't print warnings about
1722 * unresolved symbols (since there'll be too many ;) */
1723 if (is_vmlinux(modname)) {
1728 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1729 if (info.modinfo && !license && !is_vmlinux(modname))
1730 warn("modpost: missing MODULE_LICENSE() in %s\n"
1731 "see include/linux/module.h for "
1732 "more information\n", modname);
1734 if (license_is_gpl_compatible(license))
1735 mod->gpl_compatible = 1;
1737 mod->gpl_compatible = 0;
1740 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1741 "license", license);
1744 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1745 symname = info.strtab + sym->st_name;
1747 handle_modversions(mod, &info, sym, symname);
1748 handle_moddevtable(mod, &info, sym, symname);
1750 if (!is_vmlinux(modname) ||
1751 (is_vmlinux(modname) && vmlinux_section_warnings))
1752 check_sec_ref(mod, modname, &info);
1754 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1756 maybe_frob_rcs_version(modname, version, info.modinfo,
1757 version - (char *)info.hdr);
1758 if (version || (all_versions && !is_vmlinux(modname)))
1759 get_src_version(modname, mod->srcversion,
1760 sizeof(mod->srcversion)-1);
1762 parse_elf_finish(&info);
1764 /* Our trick to get versioning for module struct etc. - it's
1765 * never passed as an argument to an exported function, so
1766 * the automatic versioning doesn't pick it up, but it's really
1767 * important anyhow */
1769 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1774 /* We first write the generated file into memory using the
1775 * following helper, then compare to the file on disk and
1776 * only update the later if anything changed */
1778 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1779 const char *fmt, ...)
1786 len = vsnprintf(tmp, SZ, fmt, ap);
1787 buf_write(buf, tmp, len);
1791 void buf_write(struct buffer *buf, const char *s, int len)
1793 if (buf->size - buf->pos < len) {
1794 buf->size += len + SZ;
1795 buf->p = realloc(buf->p, buf->size);
1797 strncpy(buf->p + buf->pos, s, len);
1801 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1803 const char *e = is_vmlinux(m) ?"":".ko";
1807 fatal("modpost: GPL-incompatible module %s%s "
1808 "uses GPL-only symbol '%s'\n", m, e, s);
1810 case export_unused_gpl:
1811 fatal("modpost: GPL-incompatible module %s%s "
1812 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1814 case export_gpl_future:
1815 warn("modpost: GPL-incompatible module %s%s "
1816 "uses future GPL-only symbol '%s'\n", m, e, s);
1820 case export_unknown:
1826 static void check_for_unused(enum export exp, const char *m, const char *s)
1828 const char *e = is_vmlinux(m) ?"":".ko";
1832 case export_unused_gpl:
1833 warn("modpost: module %s%s "
1834 "uses symbol '%s' marked UNUSED\n", m, e, s);
1842 static void check_exports(struct module *mod)
1844 struct symbol *s, *exp;
1846 for (s = mod->unres; s; s = s->next) {
1847 const char *basename;
1848 exp = find_symbol(s->name);
1849 if (!exp || exp->module == mod)
1851 basename = strrchr(mod->name, '/');
1855 basename = mod->name;
1856 if (!mod->gpl_compatible)
1857 check_for_gpl_usage(exp->export, basename, exp->name);
1858 check_for_unused(exp->export, basename, exp->name);
1863 * Header for the generated file
1865 static void add_header(struct buffer *b, struct module *mod)
1867 buf_printf(b, "#include <linux/module.h>\n");
1868 buf_printf(b, "#include <linux/vermagic.h>\n");
1869 buf_printf(b, "#include <linux/compiler.h>\n");
1870 buf_printf(b, "\n");
1871 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1872 buf_printf(b, "\n");
1873 buf_printf(b, "struct module __this_module\n");
1874 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1875 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1877 buf_printf(b, " .init = init_module,\n");
1878 if (mod->has_cleanup)
1879 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1880 " .exit = cleanup_module,\n"
1882 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1883 buf_printf(b, "};\n");
1886 static void add_intree_flag(struct buffer *b, int is_intree)
1889 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1892 static void add_staging_flag(struct buffer *b, const char *name)
1894 static const char *staging_dir = "drivers/staging";
1896 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1897 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1901 * Record CRCs for unresolved symbols
1903 static int add_versions(struct buffer *b, struct module *mod)
1905 struct symbol *s, *exp;
1908 for (s = mod->unres; s; s = s->next) {
1909 exp = find_symbol(s->name);
1910 if (!exp || exp->module == mod) {
1911 if (have_vmlinux && !s->weak) {
1912 if (warn_unresolved) {
1913 warn("\"%s\" [%s.ko] undefined!\n",
1914 s->name, mod->name);
1916 merror("\"%s\" [%s.ko] undefined!\n",
1917 s->name, mod->name);
1923 s->module = exp->module;
1924 s->crc_valid = exp->crc_valid;
1931 buf_printf(b, "\n");
1932 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1933 buf_printf(b, "__used\n");
1934 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1936 for (s = mod->unres; s; s = s->next) {
1939 if (!s->crc_valid) {
1940 warn("\"%s\" [%s.ko] has no CRC!\n",
1941 s->name, mod->name);
1944 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1947 buf_printf(b, "};\n");
1952 static void add_depends(struct buffer *b, struct module *mod,
1953 struct module *modules)
1959 for (m = modules; m; m = m->next)
1960 m->seen = is_vmlinux(m->name);
1962 buf_printf(b, "\n");
1963 buf_printf(b, "static const char __module_depends[]\n");
1964 buf_printf(b, "__used\n");
1965 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1966 buf_printf(b, "\"depends=");
1967 for (s = mod->unres; s; s = s->next) {
1972 if (s->module->seen)
1975 s->module->seen = 1;
1976 p = strrchr(s->module->name, '/');
1980 p = s->module->name;
1981 buf_printf(b, "%s%s", first ? "" : ",", p);
1984 buf_printf(b, "\";\n");
1987 static void add_srcversion(struct buffer *b, struct module *mod)
1989 if (mod->srcversion[0]) {
1990 buf_printf(b, "\n");
1991 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1996 static void write_if_changed(struct buffer *b, const char *fname)
2002 file = fopen(fname, "r");
2006 if (fstat(fileno(file), &st) < 0)
2009 if (st.st_size != b->pos)
2012 tmp = NOFAIL(malloc(b->pos));
2013 if (fread(tmp, 1, b->pos, file) != b->pos)
2016 if (memcmp(tmp, b->p, b->pos) != 0)
2028 file = fopen(fname, "w");
2033 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2040 /* parse Module.symvers file. line format:
2041 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2043 static void read_dump(const char *fname, unsigned int kernel)
2045 unsigned long size, pos = 0;
2046 void *file = grab_file(fname, &size);
2050 /* No symbol versions, silently ignore */
2053 while ((line = get_next_line(&pos, file, size))) {
2054 char *symname, *modname, *d, *export, *end;
2059 if (!(symname = strchr(line, '\t')))
2062 if (!(modname = strchr(symname, '\t')))
2065 if ((export = strchr(modname, '\t')) != NULL)
2067 if (export && ((end = strchr(export, '\t')) != NULL))
2069 crc = strtoul(line, &d, 16);
2070 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2072 mod = find_module(modname);
2074 if (is_vmlinux(modname))
2076 mod = new_module(modname);
2079 s = sym_add_exported(symname, mod, export_no(export));
2082 sym_update_crc(symname, mod, crc, export_no(export));
2086 fatal("parse error in symbol dump file\n");
2089 /* For normal builds always dump all symbols.
2090 * For external modules only dump symbols
2091 * that are not read from kernel Module.symvers.
2093 static int dump_sym(struct symbol *sym)
2095 if (!external_module)
2097 if (sym->vmlinux || sym->kernel)
2102 static void write_dump(const char *fname)
2104 struct buffer buf = { };
2105 struct symbol *symbol;
2108 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2109 symbol = symbolhash[n];
2111 if (dump_sym(symbol))
2112 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2113 symbol->crc, symbol->name,
2114 symbol->module->name,
2115 export_str(symbol->export));
2116 symbol = symbol->next;
2119 write_if_changed(&buf, fname);
2122 struct ext_sym_list {
2123 struct ext_sym_list *next;
2127 int main(int argc, char **argv)
2130 struct buffer buf = { };
2131 char *kernel_read = NULL, *module_read = NULL;
2132 char *dump_write = NULL;
2135 struct ext_sym_list *extsym_iter;
2136 struct ext_sym_list *extsym_start = NULL;
2138 while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2141 kernel_read = optarg;
2144 module_read = optarg;
2145 external_module = 1;
2151 external_module = 1;
2153 NOFAIL(malloc(sizeof(*extsym_iter)));
2154 extsym_iter->next = extsym_start;
2155 extsym_iter->file = optarg;
2156 extsym_start = extsym_iter;
2162 dump_write = optarg;
2168 vmlinux_section_warnings = 0;
2171 sec_mismatch_verbose = 0;
2174 warn_unresolved = 1;
2182 read_dump(kernel_read, 1);
2184 read_dump(module_read, 0);
2185 while (extsym_start) {
2186 read_dump(extsym_start->file, 0);
2187 extsym_iter = extsym_start->next;
2189 extsym_start = extsym_iter;
2192 while (optind < argc)
2193 read_symbols(argv[optind++]);
2195 for (mod = modules; mod; mod = mod->next) {
2203 for (mod = modules; mod; mod = mod->next) {
2204 char fname[strlen(mod->name) + 10];
2211 add_header(&buf, mod);
2212 add_intree_flag(&buf, !external_module);
2213 add_staging_flag(&buf, mod->name);
2214 err |= add_versions(&buf, mod);
2215 add_depends(&buf, mod, modules);
2216 add_moddevtable(&buf, mod);
2217 add_srcversion(&buf, mod);
2219 sprintf(fname, "%s.mod.c", mod->name);
2220 write_if_changed(&buf, fname);
2224 write_dump(dump_write);
2225 if (sec_mismatch_count && !sec_mismatch_verbose)
2226 warn("modpost: Found %d section mismatch(es).\n"
2227 "To see full details build your kernel with:\n"
2228 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2229 sec_mismatch_count);