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? */
32 /* Warn about undefined symbols? (do so if we have vmlinux) */
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)
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)
340 void *map = MAP_FAILED;
343 fd = open(filename, O_RDONLY);
350 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
354 if (map == MAP_FAILED)
360 * Return a copy of the next line in a mmap'ed file.
361 * spaces in the beginning of the line is trimmed away.
362 * Return a pointer to a static buffer.
364 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
366 static char line[4096];
369 signed char *p = (signed char *)file + *pos;
372 for (; *pos < size ; (*pos)++) {
373 if (skip && isspace(*p)) {
378 if (*p != '\n' && (*pos < size)) {
382 break; /* Too long, stop */
393 void release_file(void *file, unsigned long size)
398 static int parse_elf(struct elf_info *info, const char *filename)
404 const char *secstrings;
405 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
407 hdr = grab_file(filename, &info->size);
413 if (info->size < sizeof(*hdr)) {
414 /* file too small, assume this is an empty .o file */
417 /* Is this a valid ELF file? */
418 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
419 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
420 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
421 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
422 /* Not an ELF file - silently ignore it */
425 /* Fix endianness in ELF header */
426 hdr->e_type = TO_NATIVE(hdr->e_type);
427 hdr->e_machine = TO_NATIVE(hdr->e_machine);
428 hdr->e_version = TO_NATIVE(hdr->e_version);
429 hdr->e_entry = TO_NATIVE(hdr->e_entry);
430 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
431 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
432 hdr->e_flags = TO_NATIVE(hdr->e_flags);
433 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
434 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
435 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
436 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
437 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
438 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
439 sechdrs = (void *)hdr + hdr->e_shoff;
440 info->sechdrs = sechdrs;
442 /* Check if file offset is correct */
443 if (hdr->e_shoff > info->size) {
444 fatal("section header offset=%lu in file '%s' is bigger than "
445 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
446 filename, info->size);
450 if (hdr->e_shnum == SHN_UNDEF) {
452 * There are more than 64k sections,
453 * read count from .sh_size.
455 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
458 info->num_sections = hdr->e_shnum;
460 if (hdr->e_shstrndx == SHN_XINDEX) {
461 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
464 info->secindex_strings = hdr->e_shstrndx;
467 /* Fix endianness in section headers */
468 for (i = 0; i < info->num_sections; i++) {
469 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
470 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
471 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
472 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
473 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
474 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
475 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
476 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
477 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
478 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
480 /* Find symbol table. */
481 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
482 for (i = 1; i < info->num_sections; i++) {
484 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
486 if (!nobits && sechdrs[i].sh_offset > info->size) {
487 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
488 "sizeof(*hrd)=%zu\n", filename,
489 (unsigned long)sechdrs[i].sh_offset,
493 secname = secstrings + sechdrs[i].sh_name;
494 if (strcmp(secname, ".modinfo") == 0) {
496 fatal("%s has NOBITS .modinfo\n", filename);
497 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
498 info->modinfo_len = sechdrs[i].sh_size;
499 } else if (strcmp(secname, "__ksymtab") == 0)
500 info->export_sec = i;
501 else if (strcmp(secname, "__ksymtab_unused") == 0)
502 info->export_unused_sec = i;
503 else if (strcmp(secname, "__ksymtab_gpl") == 0)
504 info->export_gpl_sec = i;
505 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
506 info->export_unused_gpl_sec = i;
507 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
508 info->export_gpl_future_sec = i;
510 if (sechdrs[i].sh_type == SHT_SYMTAB) {
511 unsigned int sh_link_idx;
513 info->symtab_start = (void *)hdr +
514 sechdrs[i].sh_offset;
515 info->symtab_stop = (void *)hdr +
516 sechdrs[i].sh_offset + sechdrs[i].sh_size;
517 sh_link_idx = sechdrs[i].sh_link;
518 info->strtab = (void *)hdr +
519 sechdrs[sh_link_idx].sh_offset;
522 /* 32bit section no. table? ("more than 64k sections") */
523 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
524 symtab_shndx_idx = i;
525 info->symtab_shndx_start = (void *)hdr +
526 sechdrs[i].sh_offset;
527 info->symtab_shndx_stop = (void *)hdr +
528 sechdrs[i].sh_offset + sechdrs[i].sh_size;
531 if (!info->symtab_start)
532 fatal("%s has no symtab?\n", filename);
534 /* Fix endianness in symbols */
535 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
536 sym->st_shndx = TO_NATIVE(sym->st_shndx);
537 sym->st_name = TO_NATIVE(sym->st_name);
538 sym->st_value = TO_NATIVE(sym->st_value);
539 sym->st_size = TO_NATIVE(sym->st_size);
542 if (symtab_shndx_idx != ~0U) {
544 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
545 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
546 filename, sechdrs[symtab_shndx_idx].sh_link,
549 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
557 static void parse_elf_finish(struct elf_info *info)
559 release_file(info->hdr, info->size);
562 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
564 /* ignore __this_module, it will be resolved shortly */
565 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
567 /* ignore global offset table */
568 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
570 if (info->hdr->e_machine == EM_PPC)
571 /* Special register function linked on all modules during final link of .ko */
572 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
573 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
574 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
575 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
577 if (info->hdr->e_machine == EM_PPC64)
578 /* Special register function linked on all modules during final link of .ko */
579 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
580 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
582 /* Do not ignore this symbol */
586 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
587 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
589 static void handle_modversions(struct module *mod, struct elf_info *info,
590 Elf_Sym *sym, const char *symname)
595 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
596 strncmp(symname, "__ksymtab", 9) == 0)
597 export = export_from_secname(info, get_secindex(info, sym));
599 export = export_from_sec(info, get_secindex(info, sym));
601 switch (sym->st_shndx) {
603 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
607 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
608 crc = (unsigned int) sym->st_value;
609 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
614 /* undefined symbol */
615 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
616 ELF_ST_BIND(sym->st_info) != STB_WEAK)
618 if (ignore_undef_symbol(info, symname))
620 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
621 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
622 /* add compatibility with older glibc */
623 #ifndef STT_SPARC_REGISTER
624 #define STT_SPARC_REGISTER STT_REGISTER
626 if (info->hdr->e_machine == EM_SPARC ||
627 info->hdr->e_machine == EM_SPARCV9) {
628 /* Ignore register directives. */
629 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
631 if (symname[0] == '.') {
632 char *munged = strdup(symname);
634 munged[1] = toupper(munged[1]);
640 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
641 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
643 alloc_symbol(symname +
644 strlen(MODULE_SYMBOL_PREFIX),
645 ELF_ST_BIND(sym->st_info) == STB_WEAK,
650 /* All exported symbols */
651 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
652 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
655 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
657 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
658 mod->has_cleanup = 1;
664 * Parse tag=value strings from .modinfo section
666 static char *next_string(char *string, unsigned long *secsize)
668 /* Skip non-zero chars */
671 if ((*secsize)-- <= 1)
675 /* Skip any zero padding. */
678 if ((*secsize)-- <= 1)
684 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
685 const char *tag, char *info)
688 unsigned int taglen = strlen(tag);
689 unsigned long size = modinfo_len;
692 size -= info - (char *)modinfo;
693 modinfo = next_string(info, &size);
696 for (p = modinfo; p; p = next_string(p, &size)) {
697 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
698 return p + taglen + 1;
703 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
707 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
711 * Test if string s ends in string sub
714 static int strrcmp(const char *s, const char *sub)
722 sublen = strlen(sub);
724 if ((slen == 0) || (sublen == 0))
730 return memcmp(s + slen - sublen, sub, sublen);
733 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
736 return elf->strtab + sym->st_name;
741 static const char *sec_name(struct elf_info *elf, int secindex)
743 Elf_Shdr *sechdrs = elf->sechdrs;
744 return (void *)elf->hdr +
745 elf->sechdrs[elf->secindex_strings].sh_offset +
746 sechdrs[secindex].sh_name;
749 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
751 return (void *)elf->hdr +
752 elf->sechdrs[elf->secindex_strings].sh_offset +
756 /* if sym is empty or point to a string
757 * like ".[0-9]+" then return 1.
758 * This is the optional prefix added by ld to some sections
760 static int number_prefix(const char *sym)
768 if (c < '0' || c > '9')
774 /* The pattern is an array of simple patterns.
775 * "foo" will match an exact string equal to "foo"
776 * "*foo" will match a string that ends with "foo"
777 * "foo*" will match a string that begins with "foo"
778 * "foo$" will match a string equal to "foo" or "foo.1"
779 * where the '1' can be any number including several digits.
780 * The $ syntax is for sections where ld append a dot number
781 * to make section name unique.
783 static int match(const char *sym, const char * const pat[])
788 const char *endp = p + strlen(p) - 1;
792 if (strrcmp(sym, p + 1) == 0)
796 else if (*endp == '*') {
797 if (strncmp(sym, p, strlen(p) - 1) == 0)
801 else if (*endp == '$') {
802 if (strncmp(sym, p, strlen(p) - 1) == 0) {
803 if (number_prefix(sym + strlen(p) - 1))
809 if (strcmp(p, sym) == 0)
817 /* sections that we do not want to do full section mismatch check on */
818 static const char *section_white_list[] =
822 ".zdebug*", /* Compressed debug sections. */
823 ".GCC-command-line", /* mn10300 */
824 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
825 ".mdebug*", /* alpha, score, mips etc. */
826 ".pdr", /* alpha, score, mips etc. */
831 ".xt.prop", /* xtensa */
832 ".xt.lit", /* xtensa */
837 * This is used to find sections missing the SHF_ALLOC flag.
838 * The cause of this is often a section specified in assembler
839 * without "ax" / "aw".
841 static void check_section(const char *modname, struct elf_info *elf,
844 const char *sec = sech_name(elf, sechdr);
846 if (sechdr->sh_type == SHT_PROGBITS &&
847 !(sechdr->sh_flags & SHF_ALLOC) &&
848 !match(sec, section_white_list)) {
849 warn("%s (%s): unexpected non-allocatable section.\n"
850 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
851 "Note that for example <linux/init.h> contains\n"
852 "section definitions for use in .S files.\n\n",
859 #define ALL_INIT_DATA_SECTIONS \
860 ".init.setup$", ".init.rodata$", \
861 ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$", \
862 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
863 #define ALL_EXIT_DATA_SECTIONS \
864 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
866 #define ALL_INIT_TEXT_SECTIONS \
867 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
868 #define ALL_EXIT_TEXT_SECTIONS \
869 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
871 #define ALL_PCI_INIT_SECTIONS \
872 ".pci_fixup_early$", ".pci_fixup_header$", ".pci_fixup_final$", \
873 ".pci_fixup_enable$", ".pci_fixup_resume$", \
874 ".pci_fixup_resume_early$", ".pci_fixup_suspend$"
876 #define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
878 #define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
881 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
882 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
884 #define DATA_SECTIONS ".data$", ".data.rel$"
885 #define TEXT_SECTIONS ".text$"
887 #define INIT_SECTIONS ".init.*"
888 #define DEV_INIT_SECTIONS ".devinit.*"
889 #define CPU_INIT_SECTIONS ".cpuinit.*"
890 #define MEM_INIT_SECTIONS ".meminit.*"
892 #define EXIT_SECTIONS ".exit.*"
893 #define DEV_EXIT_SECTIONS ".devexit.*"
894 #define CPU_EXIT_SECTIONS ".cpuexit.*"
895 #define MEM_EXIT_SECTIONS ".memexit.*"
897 /* init data sections */
898 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
900 /* all init sections */
901 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
903 /* All init and exit sections (code + data) */
904 static const char *init_exit_sections[] =
905 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
908 static const char *data_sections[] = { DATA_SECTIONS, NULL };
911 /* symbols in .data that may refer to init/exit sections */
912 #define DEFAULT_SYMBOL_WHITE_LIST \
914 "*_template", /* scsi uses *_template a lot */ \
915 "*_timer", /* arm uses ops structures named _timer a lot */ \
916 "*_sht", /* scsi also used *_sht to some extent */ \
922 static const char *head_sections[] = { ".head.text*", NULL };
923 static const char *linker_symbols[] =
924 { "__init_begin", "_sinittext", "_einittext", NULL };
931 XXXINIT_TO_SOME_INIT,
932 XXXEXIT_TO_SOME_EXIT,
933 ANY_INIT_TO_ANY_EXIT,
934 ANY_EXIT_TO_ANY_INIT,
938 struct sectioncheck {
939 const char *fromsec[20];
940 const char *tosec[20];
941 enum mismatch mismatch;
942 const char *symbol_white_list[20];
945 const struct sectioncheck sectioncheck[] = {
946 /* Do not reference init/exit code/data from
947 * normal code and data
950 .fromsec = { TEXT_SECTIONS, NULL },
951 .tosec = { ALL_INIT_SECTIONS, NULL },
952 .mismatch = TEXT_TO_ANY_INIT,
953 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
956 .fromsec = { DATA_SECTIONS, NULL },
957 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
958 .mismatch = DATA_TO_ANY_INIT,
959 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
962 .fromsec = { DATA_SECTIONS, NULL },
963 .tosec = { INIT_SECTIONS, NULL },
964 .mismatch = DATA_TO_ANY_INIT,
965 .symbol_white_list = {
966 "*_template", "*_timer", "*_sht", "*_ops",
967 "*_probe", "*_probe_one", "*_console", NULL
971 .fromsec = { TEXT_SECTIONS, NULL },
972 .tosec = { ALL_EXIT_SECTIONS, NULL },
973 .mismatch = TEXT_TO_ANY_EXIT,
974 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
977 .fromsec = { DATA_SECTIONS, NULL },
978 .tosec = { ALL_EXIT_SECTIONS, NULL },
979 .mismatch = DATA_TO_ANY_EXIT,
980 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
982 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */
984 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
985 .tosec = { INIT_SECTIONS, NULL },
986 .mismatch = XXXINIT_TO_SOME_INIT,
987 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
989 /* Do not reference cpuinit code/data from meminit code/data */
991 .fromsec = { MEM_INIT_SECTIONS, NULL },
992 .tosec = { CPU_INIT_SECTIONS, NULL },
993 .mismatch = XXXINIT_TO_SOME_INIT,
994 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
996 /* Do not reference meminit code/data from cpuinit code/data */
998 .fromsec = { CPU_INIT_SECTIONS, NULL },
999 .tosec = { MEM_INIT_SECTIONS, NULL },
1000 .mismatch = XXXINIT_TO_SOME_INIT,
1001 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1003 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
1005 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1006 .tosec = { EXIT_SECTIONS, NULL },
1007 .mismatch = XXXEXIT_TO_SOME_EXIT,
1008 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1010 /* Do not reference cpuexit code/data from memexit code/data */
1012 .fromsec = { MEM_EXIT_SECTIONS, NULL },
1013 .tosec = { CPU_EXIT_SECTIONS, NULL },
1014 .mismatch = XXXEXIT_TO_SOME_EXIT,
1015 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1017 /* Do not reference memexit code/data from cpuexit code/data */
1019 .fromsec = { CPU_EXIT_SECTIONS, NULL },
1020 .tosec = { MEM_EXIT_SECTIONS, NULL },
1021 .mismatch = XXXEXIT_TO_SOME_EXIT,
1022 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1024 /* Do not use exit code/data from init code */
1026 .fromsec = { ALL_INIT_SECTIONS, NULL },
1027 .tosec = { ALL_EXIT_SECTIONS, NULL },
1028 .mismatch = ANY_INIT_TO_ANY_EXIT,
1029 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1031 /* Do not use init code/data from exit code */
1033 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1034 .tosec = { ALL_INIT_SECTIONS, NULL },
1035 .mismatch = ANY_EXIT_TO_ANY_INIT,
1036 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1039 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1040 .tosec = { INIT_SECTIONS, NULL },
1041 .mismatch = ANY_INIT_TO_ANY_EXIT,
1042 .symbol_white_list = { NULL },
1044 /* Do not export init/exit functions or data */
1046 .fromsec = { "__ksymtab*", NULL },
1047 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1048 .mismatch = EXPORT_TO_INIT_EXIT,
1049 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1053 static const struct sectioncheck *section_mismatch(
1054 const char *fromsec, const char *tosec)
1057 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1058 const struct sectioncheck *check = §ioncheck[0];
1060 for (i = 0; i < elems; i++) {
1061 if (match(fromsec, check->fromsec) &&
1062 match(tosec, check->tosec))
1070 * Whitelist to allow certain references to pass with no warning.
1073 * If a module parameter is declared __initdata and permissions=0
1074 * then this is legal despite the warning generated.
1075 * We cannot see value of permissions here, so just ignore
1077 * The pattern is identified by:
1078 * tosec = .init.data
1083 * module_param_call() ops can refer to __init set function if permissions=0
1084 * The pattern is identified by:
1085 * tosec = .init.text
1087 * atsym = __param_ops_*
1090 * Many drivers utilise a *driver container with references to
1091 * add, remove, probe functions etc.
1092 * These functions may often be marked __devinit and we do not want to
1094 * the pattern is identified by:
1095 * tosec = init or exit section
1096 * fromsec = data section
1097 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1098 * *probe_one, *_console, *_timer
1101 * Whitelist all references from .head.text to any init section
1104 * Some symbols belong to init section but still it is ok to reference
1105 * these from non-init sections as these symbols don't have any memory
1106 * allocated for them and symbol address and value are same. So even
1107 * if init section is freed, its ok to reference those symbols.
1108 * For ex. symbols marking the init section boundaries.
1109 * This pattern is identified by
1110 * refsymname = __init_begin, _sinittext, _einittext
1113 static int secref_whitelist(const struct sectioncheck *mismatch,
1114 const char *fromsec, const char *fromsym,
1115 const char *tosec, const char *tosym)
1117 /* Check for pattern 1 */
1118 if (match(tosec, init_data_sections) &&
1119 match(fromsec, data_sections) &&
1120 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1123 /* Check for pattern 1a */
1124 if (strcmp(tosec, ".init.text") == 0 &&
1125 match(fromsec, data_sections) &&
1126 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1129 /* Check for pattern 2 */
1130 if (match(tosec, init_exit_sections) &&
1131 match(fromsec, data_sections) &&
1132 match(fromsym, mismatch->symbol_white_list))
1135 /* Check for pattern 3 */
1136 if (match(fromsec, head_sections) &&
1137 match(tosec, init_sections))
1140 /* Check for pattern 4 */
1141 if (match(tosym, linker_symbols))
1148 * Find symbol based on relocation record info.
1149 * In some cases the symbol supplied is a valid symbol so
1150 * return refsym. If st_name != 0 we assume this is a valid symbol.
1151 * In other cases the symbol needs to be looked up in the symbol table
1152 * based on section and address.
1154 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1158 Elf_Sym *near = NULL;
1159 Elf64_Sword distance = 20;
1161 unsigned int relsym_secindex;
1163 if (relsym->st_name != 0)
1166 relsym_secindex = get_secindex(elf, relsym);
1167 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1168 if (get_secindex(elf, sym) != relsym_secindex)
1170 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1172 if (sym->st_value == addr)
1174 /* Find a symbol nearby - addr are maybe negative */
1175 d = sym->st_value - addr;
1177 d = addr - sym->st_value;
1183 /* We need a close match */
1190 static inline int is_arm_mapping_symbol(const char *str)
1192 return str[0] == '$' && strchr("atd", str[1])
1193 && (str[2] == '\0' || str[2] == '.');
1197 * If there's no name there, ignore it; likewise, ignore it if it's
1198 * one of the magic symbols emitted used by current ARM tools.
1200 * Otherwise if find_symbols_between() returns those symbols, they'll
1201 * fail the whitelist tests and cause lots of false alarms ... fixable
1202 * only by merging __exit and __init sections into __text, bloating
1203 * the kernel (which is especially evil on embedded platforms).
1205 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1207 const char *name = elf->strtab + sym->st_name;
1209 if (!name || !strlen(name))
1211 return !is_arm_mapping_symbol(name);
1215 * Find symbols before or equal addr and after addr - in the section sec.
1216 * If we find two symbols with equal offset prefer one with a valid name.
1217 * The ELF format may have a better way to detect what type of symbol
1218 * it is, but this works for now.
1220 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1224 Elf_Sym *near = NULL;
1225 Elf_Addr distance = ~0;
1227 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1230 if (is_shndx_special(sym->st_shndx))
1232 symsec = sec_name(elf, get_secindex(elf, sym));
1233 if (strcmp(symsec, sec) != 0)
1235 if (!is_valid_name(elf, sym))
1237 if (sym->st_value <= addr) {
1238 if ((addr - sym->st_value) < distance) {
1239 distance = addr - sym->st_value;
1241 } else if ((addr - sym->st_value) == distance) {
1250 * Convert a section name to the function/data attribute
1251 * .init.text => __init
1252 * .cpuinit.data => __cpudata
1253 * .memexitconst => __memconst
1256 * The memory of returned value has been allocated on a heap. The user of this
1257 * method should free it after usage.
1259 static char *sec2annotation(const char *s)
1261 if (match(s, init_exit_sections)) {
1262 char *p = malloc(20);
1269 while (*s && *s != '.')
1274 if (strstr(s, "rodata") != NULL)
1275 strcat(p, "const ");
1276 else if (strstr(s, "data") != NULL)
1286 static int is_function(Elf_Sym *sym)
1289 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1294 static void print_section_list(const char * const list[20])
1296 const char *const *s = list;
1299 fprintf(stderr, "%s", *s);
1302 fprintf(stderr, ", ");
1304 fprintf(stderr, "\n");
1308 * Print a warning about a section mismatch.
1309 * Try to find symbols near it so user can find it.
1310 * Check whitelist before warning - it may be a false positive.
1312 static void report_sec_mismatch(const char *modname,
1313 const struct sectioncheck *mismatch,
1314 const char *fromsec,
1315 unsigned long long fromaddr,
1316 const char *fromsym,
1318 const char *tosec, const char *tosym,
1321 const char *from, *from_p;
1322 const char *to, *to_p;
1326 switch (from_is_func) {
1327 case 0: from = "variable"; from_p = ""; break;
1328 case 1: from = "function"; from_p = "()"; break;
1329 default: from = "(unknown reference)"; from_p = ""; break;
1331 switch (to_is_func) {
1332 case 0: to = "variable"; to_p = ""; break;
1333 case 1: to = "function"; to_p = "()"; break;
1334 default: to = "(unknown reference)"; to_p = ""; break;
1337 sec_mismatch_count++;
1338 if (!sec_mismatch_verbose)
1341 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1342 "to the %s %s:%s%s\n",
1343 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1346 switch (mismatch->mismatch) {
1347 case TEXT_TO_ANY_INIT:
1348 prl_from = sec2annotation(fromsec);
1349 prl_to = sec2annotation(tosec);
1351 "The function %s%s() references\n"
1353 "This is often because %s lacks a %s\n"
1354 "annotation or the annotation of %s is wrong.\n",
1356 to, prl_to, tosym, to_p,
1357 fromsym, prl_to, tosym);
1361 case DATA_TO_ANY_INIT: {
1362 prl_to = sec2annotation(tosec);
1364 "The variable %s references\n"
1366 "If the reference is valid then annotate the\n"
1367 "variable with __init* or __refdata (see linux/init.h) "
1368 "or name the variable:\n",
1369 fromsym, to, prl_to, tosym, to_p);
1370 print_section_list(mismatch->symbol_white_list);
1374 case TEXT_TO_ANY_EXIT:
1375 prl_to = sec2annotation(tosec);
1377 "The function %s() references a %s in an exit section.\n"
1378 "Often the %s %s%s has valid usage outside the exit section\n"
1379 "and the fix is to remove the %sannotation of %s.\n",
1380 fromsym, to, to, tosym, to_p, prl_to, tosym);
1383 case DATA_TO_ANY_EXIT: {
1384 prl_to = sec2annotation(tosec);
1386 "The variable %s references\n"
1388 "If the reference is valid then annotate the\n"
1389 "variable with __exit* (see linux/init.h) or "
1390 "name the variable:\n",
1391 fromsym, to, prl_to, tosym, to_p);
1392 print_section_list(mismatch->symbol_white_list);
1396 case XXXINIT_TO_SOME_INIT:
1397 case XXXEXIT_TO_SOME_EXIT:
1398 prl_from = sec2annotation(fromsec);
1399 prl_to = sec2annotation(tosec);
1401 "The %s %s%s%s references\n"
1403 "If %s is only used by %s then\n"
1404 "annotate %s with a matching annotation.\n",
1405 from, prl_from, fromsym, from_p,
1406 to, prl_to, tosym, to_p,
1407 tosym, fromsym, tosym);
1411 case ANY_INIT_TO_ANY_EXIT:
1412 prl_from = sec2annotation(fromsec);
1413 prl_to = sec2annotation(tosec);
1415 "The %s %s%s%s references\n"
1417 "This is often seen when error handling "
1418 "in the init function\n"
1419 "uses functionality in the exit path.\n"
1420 "The fix is often to remove the %sannotation of\n"
1421 "%s%s so it may be used outside an exit section.\n",
1422 from, prl_from, fromsym, from_p,
1423 to, prl_to, tosym, to_p,
1424 prl_to, tosym, to_p);
1428 case ANY_EXIT_TO_ANY_INIT:
1429 prl_from = sec2annotation(fromsec);
1430 prl_to = sec2annotation(tosec);
1432 "The %s %s%s%s references\n"
1434 "This is often seen when error handling "
1435 "in the exit function\n"
1436 "uses functionality in the init path.\n"
1437 "The fix is often to remove the %sannotation of\n"
1438 "%s%s so it may be used outside an init section.\n",
1439 from, prl_from, fromsym, from_p,
1440 to, prl_to, tosym, to_p,
1441 prl_to, tosym, to_p);
1445 case EXPORT_TO_INIT_EXIT:
1446 prl_to = sec2annotation(tosec);
1448 "The symbol %s is exported and annotated %s\n"
1449 "Fix this by removing the %sannotation of %s "
1450 "or drop the export.\n",
1451 tosym, prl_to, prl_to, tosym);
1455 fprintf(stderr, "\n");
1458 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1459 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1462 const struct sectioncheck *mismatch;
1464 tosec = sec_name(elf, get_secindex(elf, sym));
1465 mismatch = section_mismatch(fromsec, tosec);
1470 const char *fromsym;
1472 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1473 fromsym = sym_name(elf, from);
1474 to = find_elf_symbol(elf, r->r_addend, sym);
1475 tosym = sym_name(elf, to);
1477 /* check whitelist - we may ignore it */
1478 if (secref_whitelist(mismatch,
1479 fromsec, fromsym, tosec, tosym)) {
1480 report_sec_mismatch(modname, mismatch,
1481 fromsec, r->r_offset, fromsym,
1482 is_function(from), tosec, tosym,
1488 static unsigned int *reloc_location(struct elf_info *elf,
1489 Elf_Shdr *sechdr, Elf_Rela *r)
1491 Elf_Shdr *sechdrs = elf->sechdrs;
1492 int section = sechdr->sh_info;
1494 return (void *)elf->hdr + sechdrs[section].sh_offset +
1498 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1500 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1501 unsigned int *location = reloc_location(elf, sechdr, r);
1505 r->r_addend = TO_NATIVE(*location);
1508 r->r_addend = TO_NATIVE(*location) + 4;
1509 /* For CONFIG_RELOCATABLE=y */
1510 if (elf->hdr->e_type == ET_EXEC)
1511 r->r_addend += r->r_offset;
1518 #define R_ARM_CALL 28
1520 #ifndef R_ARM_JUMP24
1521 #define R_ARM_JUMP24 29
1524 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1526 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1530 /* From ARM ABI: (S + A) | T */
1531 r->r_addend = (int)(long)
1532 (elf->symtab_start + ELF_R_SYM(r->r_info));
1537 /* From ARM ABI: ((S + A) | T) - P */
1538 r->r_addend = (int)(long)(elf->hdr +
1540 (r->r_offset - sechdr->sh_addr));
1548 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1550 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1551 unsigned int *location = reloc_location(elf, sechdr, r);
1554 if (r_typ == R_MIPS_HI16)
1555 return 1; /* skip this */
1556 inst = TO_NATIVE(*location);
1559 r->r_addend = inst & 0xffff;
1562 r->r_addend = (inst & 0x03ffffff) << 2;
1571 static void section_rela(const char *modname, struct elf_info *elf,
1578 const char *fromsec;
1580 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1581 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1583 fromsec = sech_name(elf, sechdr);
1584 fromsec += strlen(".rela");
1585 /* if from section (name) is know good then skip it */
1586 if (match(fromsec, section_white_list))
1589 for (rela = start; rela < stop; rela++) {
1590 r.r_offset = TO_NATIVE(rela->r_offset);
1591 #if KERNEL_ELFCLASS == ELFCLASS64
1592 if (elf->hdr->e_machine == EM_MIPS) {
1594 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1595 r_sym = TO_NATIVE(r_sym);
1596 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1597 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1599 r.r_info = TO_NATIVE(rela->r_info);
1600 r_sym = ELF_R_SYM(r.r_info);
1603 r.r_info = TO_NATIVE(rela->r_info);
1604 r_sym = ELF_R_SYM(r.r_info);
1606 r.r_addend = TO_NATIVE(rela->r_addend);
1607 sym = elf->symtab_start + r_sym;
1608 /* Skip special sections */
1609 if (is_shndx_special(sym->st_shndx))
1611 check_section_mismatch(modname, elf, &r, sym, fromsec);
1615 static void section_rel(const char *modname, struct elf_info *elf,
1622 const char *fromsec;
1624 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1625 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1627 fromsec = sech_name(elf, sechdr);
1628 fromsec += strlen(".rel");
1629 /* if from section (name) is know good then skip it */
1630 if (match(fromsec, section_white_list))
1633 for (rel = start; rel < stop; rel++) {
1634 r.r_offset = TO_NATIVE(rel->r_offset);
1635 #if KERNEL_ELFCLASS == ELFCLASS64
1636 if (elf->hdr->e_machine == EM_MIPS) {
1638 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1639 r_sym = TO_NATIVE(r_sym);
1640 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1641 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1643 r.r_info = TO_NATIVE(rel->r_info);
1644 r_sym = ELF_R_SYM(r.r_info);
1647 r.r_info = TO_NATIVE(rel->r_info);
1648 r_sym = ELF_R_SYM(r.r_info);
1651 switch (elf->hdr->e_machine) {
1653 if (addend_386_rel(elf, sechdr, &r))
1657 if (addend_arm_rel(elf, sechdr, &r))
1661 if (addend_mips_rel(elf, sechdr, &r))
1665 sym = elf->symtab_start + r_sym;
1666 /* Skip special sections */
1667 if (is_shndx_special(sym->st_shndx))
1669 check_section_mismatch(modname, elf, &r, sym, fromsec);
1674 * A module includes a number of sections that are discarded
1675 * either when loaded or when used as built-in.
1676 * For loaded modules all functions marked __init and all data
1677 * marked __initdata will be discarded when the module has been initialized.
1678 * Likewise for modules used built-in the sections marked __exit
1679 * are discarded because __exit marked function are supposed to be called
1680 * only when a module is unloaded which never happens for built-in modules.
1681 * The check_sec_ref() function traverses all relocation records
1682 * to find all references to a section that reference a section that will
1683 * be discarded and warns about it.
1685 static void check_sec_ref(struct module *mod, const char *modname,
1686 struct elf_info *elf)
1689 Elf_Shdr *sechdrs = elf->sechdrs;
1691 /* Walk through all sections */
1692 for (i = 0; i < elf->num_sections; i++) {
1693 check_section(modname, elf, &elf->sechdrs[i]);
1694 /* We want to process only relocation sections and not .init */
1695 if (sechdrs[i].sh_type == SHT_RELA)
1696 section_rela(modname, elf, &elf->sechdrs[i]);
1697 else if (sechdrs[i].sh_type == SHT_REL)
1698 section_rel(modname, elf, &elf->sechdrs[i]);
1702 static void read_symbols(char *modname)
1704 const char *symname;
1708 struct elf_info info = { };
1711 if (!parse_elf(&info, modname))
1714 mod = new_module(modname);
1716 /* When there's no vmlinux, don't print warnings about
1717 * unresolved symbols (since there'll be too many ;) */
1718 if (is_vmlinux(modname)) {
1723 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1724 if (info.modinfo && !license && !is_vmlinux(modname))
1725 warn("modpost: missing MODULE_LICENSE() in %s\n"
1726 "see include/linux/module.h for "
1727 "more information\n", modname);
1729 if (license_is_gpl_compatible(license))
1730 mod->gpl_compatible = 1;
1732 mod->gpl_compatible = 0;
1735 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1736 "license", license);
1739 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1740 symname = info.strtab + sym->st_name;
1742 handle_modversions(mod, &info, sym, symname);
1743 handle_moddevtable(mod, &info, sym, symname);
1745 if (!is_vmlinux(modname) ||
1746 (is_vmlinux(modname) && vmlinux_section_warnings))
1747 check_sec_ref(mod, modname, &info);
1749 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1751 maybe_frob_rcs_version(modname, version, info.modinfo,
1752 version - (char *)info.hdr);
1753 if (version || (all_versions && !is_vmlinux(modname)))
1754 get_src_version(modname, mod->srcversion,
1755 sizeof(mod->srcversion)-1);
1757 parse_elf_finish(&info);
1759 /* Our trick to get versioning for module struct etc. - it's
1760 * never passed as an argument to an exported function, so
1761 * the automatic versioning doesn't pick it up, but it's really
1762 * important anyhow */
1764 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1769 /* We first write the generated file into memory using the
1770 * following helper, then compare to the file on disk and
1771 * only update the later if anything changed */
1773 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1774 const char *fmt, ...)
1781 len = vsnprintf(tmp, SZ, fmt, ap);
1782 buf_write(buf, tmp, len);
1786 void buf_write(struct buffer *buf, const char *s, int len)
1788 if (buf->size - buf->pos < len) {
1789 buf->size += len + SZ;
1790 buf->p = realloc(buf->p, buf->size);
1792 strncpy(buf->p + buf->pos, s, len);
1796 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1798 const char *e = is_vmlinux(m) ?"":".ko";
1802 fatal("modpost: GPL-incompatible module %s%s "
1803 "uses GPL-only symbol '%s'\n", m, e, s);
1805 case export_unused_gpl:
1806 fatal("modpost: GPL-incompatible module %s%s "
1807 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1809 case export_gpl_future:
1810 warn("modpost: GPL-incompatible module %s%s "
1811 "uses future GPL-only symbol '%s'\n", m, e, s);
1815 case export_unknown:
1821 static void check_for_unused(enum export exp, const char *m, const char *s)
1823 const char *e = is_vmlinux(m) ?"":".ko";
1827 case export_unused_gpl:
1828 warn("modpost: module %s%s "
1829 "uses symbol '%s' marked UNUSED\n", m, e, s);
1837 static void check_exports(struct module *mod)
1839 struct symbol *s, *exp;
1841 for (s = mod->unres; s; s = s->next) {
1842 const char *basename;
1843 exp = find_symbol(s->name);
1844 if (!exp || exp->module == mod)
1846 basename = strrchr(mod->name, '/');
1850 basename = mod->name;
1851 if (!mod->gpl_compatible)
1852 check_for_gpl_usage(exp->export, basename, exp->name);
1853 check_for_unused(exp->export, basename, exp->name);
1858 * Header for the generated file
1860 static void add_header(struct buffer *b, struct module *mod)
1862 buf_printf(b, "#include <linux/module.h>\n");
1863 buf_printf(b, "#include <linux/vermagic.h>\n");
1864 buf_printf(b, "#include <linux/compiler.h>\n");
1865 buf_printf(b, "\n");
1866 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1867 buf_printf(b, "\n");
1868 buf_printf(b, "struct module __this_module\n");
1869 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1870 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1872 buf_printf(b, "\t.init = init_module,\n");
1873 if (mod->has_cleanup)
1874 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1875 "\t.exit = cleanup_module,\n"
1877 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1878 buf_printf(b, "};\n");
1881 static void add_intree_flag(struct buffer *b, int is_intree)
1884 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1887 static void add_staging_flag(struct buffer *b, const char *name)
1889 static const char *staging_dir = "drivers/staging";
1891 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1892 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1896 * Record CRCs for unresolved symbols
1898 static int add_versions(struct buffer *b, struct module *mod)
1900 struct symbol *s, *exp;
1903 for (s = mod->unres; s; s = s->next) {
1904 exp = find_symbol(s->name);
1905 if (!exp || exp->module == mod) {
1906 if (have_vmlinux && !s->weak) {
1907 if (warn_unresolved) {
1908 warn("\"%s\" [%s.ko] undefined!\n",
1909 s->name, mod->name);
1911 merror("\"%s\" [%s.ko] undefined!\n",
1912 s->name, mod->name);
1918 s->module = exp->module;
1919 s->crc_valid = exp->crc_valid;
1926 buf_printf(b, "\n");
1927 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1928 buf_printf(b, "__used\n");
1929 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1931 for (s = mod->unres; s; s = s->next) {
1934 if (!s->crc_valid) {
1935 warn("\"%s\" [%s.ko] has no CRC!\n",
1936 s->name, mod->name);
1939 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1942 buf_printf(b, "};\n");
1947 static void add_depends(struct buffer *b, struct module *mod,
1948 struct module *modules)
1954 for (m = modules; m; m = m->next)
1955 m->seen = is_vmlinux(m->name);
1957 buf_printf(b, "\n");
1958 buf_printf(b, "static const char __module_depends[]\n");
1959 buf_printf(b, "__used\n");
1960 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1961 buf_printf(b, "\"depends=");
1962 for (s = mod->unres; s; s = s->next) {
1967 if (s->module->seen)
1970 s->module->seen = 1;
1971 p = strrchr(s->module->name, '/');
1975 p = s->module->name;
1976 buf_printf(b, "%s%s", first ? "" : ",", p);
1979 buf_printf(b, "\";\n");
1982 static void add_srcversion(struct buffer *b, struct module *mod)
1984 if (mod->srcversion[0]) {
1985 buf_printf(b, "\n");
1986 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1991 static void write_if_changed(struct buffer *b, const char *fname)
1997 file = fopen(fname, "r");
2001 if (fstat(fileno(file), &st) < 0)
2004 if (st.st_size != b->pos)
2007 tmp = NOFAIL(malloc(b->pos));
2008 if (fread(tmp, 1, b->pos, file) != b->pos)
2011 if (memcmp(tmp, b->p, b->pos) != 0)
2023 file = fopen(fname, "w");
2028 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2035 /* parse Module.symvers file. line format:
2036 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2038 static void read_dump(const char *fname, unsigned int kernel)
2040 unsigned long size, pos = 0;
2041 void *file = grab_file(fname, &size);
2045 /* No symbol versions, silently ignore */
2048 while ((line = get_next_line(&pos, file, size))) {
2049 char *symname, *modname, *d, *export, *end;
2054 if (!(symname = strchr(line, '\t')))
2057 if (!(modname = strchr(symname, '\t')))
2060 if ((export = strchr(modname, '\t')) != NULL)
2062 if (export && ((end = strchr(export, '\t')) != NULL))
2064 crc = strtoul(line, &d, 16);
2065 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2067 mod = find_module(modname);
2069 if (is_vmlinux(modname))
2071 mod = new_module(modname);
2074 s = sym_add_exported(symname, mod, export_no(export));
2077 sym_update_crc(symname, mod, crc, export_no(export));
2081 fatal("parse error in symbol dump file\n");
2084 /* For normal builds always dump all symbols.
2085 * For external modules only dump symbols
2086 * that are not read from kernel Module.symvers.
2088 static int dump_sym(struct symbol *sym)
2090 if (!external_module)
2092 if (sym->vmlinux || sym->kernel)
2097 static void write_dump(const char *fname)
2099 struct buffer buf = { };
2100 struct symbol *symbol;
2103 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2104 symbol = symbolhash[n];
2106 if (dump_sym(symbol))
2107 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2108 symbol->crc, symbol->name,
2109 symbol->module->name,
2110 export_str(symbol->export));
2111 symbol = symbol->next;
2114 write_if_changed(&buf, fname);
2117 struct ext_sym_list {
2118 struct ext_sym_list *next;
2122 int main(int argc, char **argv)
2125 struct buffer buf = { };
2126 char *kernel_read = NULL, *module_read = NULL;
2127 char *dump_write = NULL;
2130 struct ext_sym_list *extsym_iter;
2131 struct ext_sym_list *extsym_start = NULL;
2133 while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2136 kernel_read = optarg;
2139 module_read = optarg;
2140 external_module = 1;
2146 external_module = 1;
2148 NOFAIL(malloc(sizeof(*extsym_iter)));
2149 extsym_iter->next = extsym_start;
2150 extsym_iter->file = optarg;
2151 extsym_start = extsym_iter;
2157 dump_write = optarg;
2163 vmlinux_section_warnings = 0;
2166 sec_mismatch_verbose = 0;
2169 warn_unresolved = 1;
2177 read_dump(kernel_read, 1);
2179 read_dump(module_read, 0);
2180 while (extsym_start) {
2181 read_dump(extsym_start->file, 0);
2182 extsym_iter = extsym_start->next;
2184 extsym_start = extsym_iter;
2187 while (optind < argc)
2188 read_symbols(argv[optind++]);
2190 for (mod = modules; mod; mod = mod->next) {
2198 for (mod = modules; mod; mod = mod->next) {
2199 char fname[strlen(mod->name) + 10];
2206 add_header(&buf, mod);
2207 add_intree_flag(&buf, !external_module);
2208 add_staging_flag(&buf, mod->name);
2209 err |= add_versions(&buf, mod);
2210 add_depends(&buf, mod, modules);
2211 add_moddevtable(&buf, mod);
2212 add_srcversion(&buf, mod);
2214 sprintf(fname, "%s.mod.c", mod->name);
2215 write_if_changed(&buf, fname);
2219 write_dump(dump_write);
2220 if (sec_mismatch_count && !sec_mismatch_verbose)
2221 warn("modpost: Found %d section mismatch(es).\n"
2222 "To see full details build your kernel with:\n"
2223 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2224 sec_mismatch_count);