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 ...
21 #include "../../include/generated/autoconf.h"
22 #include "../../include/linux/license.h"
23 #include "../../include/linux/export.h"
25 /* Are we using CONFIG_MODVERSIONS? */
27 /* Warn about undefined symbols? (do so if we have vmlinux) */
29 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
30 static int all_versions = 0;
31 /* If we are modposting external module set to 1 */
32 static int external_module = 0;
33 /* Warn about section mismatch in vmlinux if set to 1 */
34 static int vmlinux_section_warnings = 1;
35 /* Only warn about unresolved symbols */
36 static int warn_unresolved = 0;
37 /* How a symbol is exported */
38 static int sec_mismatch_count = 0;
39 static int sec_mismatch_verbose = 1;
42 export_plain, export_unused, export_gpl,
43 export_unused_gpl, export_gpl_future, export_unknown
46 #define PRINTF __attribute__ ((format (printf, 1, 2)))
48 PRINTF void fatal(const char *fmt, ...)
52 fprintf(stderr, "FATAL: ");
54 va_start(arglist, fmt);
55 vfprintf(stderr, fmt, arglist);
61 PRINTF void warn(const char *fmt, ...)
65 fprintf(stderr, "WARNING: ");
67 va_start(arglist, fmt);
68 vfprintf(stderr, fmt, arglist);
72 PRINTF void merror(const char *fmt, ...)
76 fprintf(stderr, "ERROR: ");
78 va_start(arglist, fmt);
79 vfprintf(stderr, fmt, arglist);
83 static inline bool strends(const char *str, const char *postfix)
85 if (strlen(str) < strlen(postfix))
88 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
91 static int is_vmlinux(const char *modname)
95 myname = strrchr(modname, '/');
101 return (strcmp(myname, "vmlinux") == 0) ||
102 (strcmp(myname, "vmlinux.o") == 0);
105 void *do_nofail(void *ptr, const char *expr)
108 fatal("modpost: Memory allocation failure: %s.\n", expr);
113 /* A list of all modules we processed */
114 static struct module *modules;
116 static struct module *find_module(char *modname)
120 for (mod = modules; mod; mod = mod->next)
121 if (strcmp(mod->name, modname) == 0)
126 static struct module *new_module(const char *modname)
131 mod = NOFAIL(malloc(sizeof(*mod)));
132 memset(mod, 0, sizeof(*mod));
133 p = NOFAIL(strdup(modname));
135 /* strip trailing .o */
136 if (strends(p, ".o")) {
137 p[strlen(p) - 2] = '\0';
143 mod->gpl_compatible = -1;
150 /* A hash of all exported symbols,
151 * struct symbol is also used for lists of unresolved symbols */
153 #define SYMBOL_HASH_SIZE 1024
157 struct module *module;
161 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
162 unsigned int kernel:1; /* 1 if symbol is from kernel
163 * (only for external modules) **/
164 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
165 enum export export; /* Type of export */
169 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
171 /* This is based on the hash agorithm from gdbm, via tdb */
172 static inline unsigned int tdb_hash(const char *name)
174 unsigned value; /* Used to compute the hash value. */
175 unsigned i; /* Used to cycle through random values. */
177 /* Set the initial value from the key size. */
178 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
179 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
181 return (1103515243 * value + 12345);
185 * Allocate a new symbols for use in the hash of exported symbols or
186 * the list of unresolved symbols per module
188 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
191 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
193 memset(s, 0, sizeof(*s));
194 strcpy(s->name, name);
200 /* For the hash of exported symbols */
201 static struct symbol *new_symbol(const char *name, struct module *module,
207 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
208 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
209 new->module = module;
210 new->export = export;
214 static struct symbol *find_symbol(const char *name)
218 /* For our purposes, .foo matches foo. PPC64 needs this. */
222 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
223 if (strcmp(s->name, name) == 0)
233 { .str = "EXPORT_SYMBOL", .export = export_plain },
234 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
235 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
236 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
237 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
238 { .str = "(unknown)", .export = export_unknown },
242 static const char *export_str(enum export ex)
244 return export_list[ex].str;
247 static enum export export_no(const char *s)
252 return export_unknown;
253 for (i = 0; export_list[i].export != export_unknown; i++) {
254 if (strcmp(export_list[i].str, s) == 0)
255 return export_list[i].export;
257 return export_unknown;
260 static const char *sec_name(struct elf_info *elf, int secindex);
262 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
264 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
266 const char *secname = sec_name(elf, sec);
268 if (strstarts(secname, "___ksymtab+"))
270 else if (strstarts(secname, "___ksymtab_unused+"))
271 return export_unused;
272 else if (strstarts(secname, "___ksymtab_gpl+"))
274 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
275 return export_unused_gpl;
276 else if (strstarts(secname, "___ksymtab_gpl_future+"))
277 return export_gpl_future;
279 return export_unknown;
282 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
284 if (sec == elf->export_sec)
286 else if (sec == elf->export_unused_sec)
287 return export_unused;
288 else if (sec == elf->export_gpl_sec)
290 else if (sec == elf->export_unused_gpl_sec)
291 return export_unused_gpl;
292 else if (sec == elf->export_gpl_future_sec)
293 return export_gpl_future;
295 return export_unknown;
299 * Add an exported symbol - it may have already been added without a
300 * CRC, in this case just update the CRC
302 static struct symbol *sym_add_exported(const char *name, struct module *mod,
305 struct symbol *s = find_symbol(name);
308 s = new_symbol(name, mod, export);
311 warn("%s: '%s' exported twice. Previous export "
312 "was in %s%s\n", mod->name, name,
314 is_vmlinux(s->module->name) ?"":".ko");
316 /* In case Modules.symvers was out of date */
321 s->vmlinux = is_vmlinux(mod->name);
327 static void sym_update_crc(const char *name, struct module *mod,
328 unsigned int crc, enum export export)
330 struct symbol *s = find_symbol(name);
333 s = new_symbol(name, mod, export);
338 void *grab_file(const char *filename, unsigned long *size)
341 void *map = MAP_FAILED;
344 fd = open(filename, O_RDONLY);
351 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
355 if (map == MAP_FAILED)
361 * Return a copy of the next line in a mmap'ed file.
362 * spaces in the beginning of the line is trimmed away.
363 * Return a pointer to a static buffer.
365 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
367 static char line[4096];
370 signed char *p = (signed char *)file + *pos;
373 for (; *pos < size ; (*pos)++) {
374 if (skip && isspace(*p)) {
379 if (*p != '\n' && (*pos < size)) {
383 break; /* Too long, stop */
394 void release_file(void *file, unsigned long size)
399 static int parse_elf(struct elf_info *info, const char *filename)
405 const char *secstrings;
406 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
408 hdr = grab_file(filename, &info->size);
414 if (info->size < sizeof(*hdr)) {
415 /* file too small, assume this is an empty .o file */
418 /* Is this a valid ELF file? */
419 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
420 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
421 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
422 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
423 /* Not an ELF file - silently ignore it */
426 /* Fix endianness in ELF header */
427 hdr->e_type = TO_NATIVE(hdr->e_type);
428 hdr->e_machine = TO_NATIVE(hdr->e_machine);
429 hdr->e_version = TO_NATIVE(hdr->e_version);
430 hdr->e_entry = TO_NATIVE(hdr->e_entry);
431 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
432 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
433 hdr->e_flags = TO_NATIVE(hdr->e_flags);
434 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
435 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
436 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
437 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
438 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
439 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
440 sechdrs = (void *)hdr + hdr->e_shoff;
441 info->sechdrs = sechdrs;
443 /* Check if file offset is correct */
444 if (hdr->e_shoff > info->size) {
445 fatal("section header offset=%lu in file '%s' is bigger than "
446 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
447 filename, info->size);
451 if (hdr->e_shnum == SHN_UNDEF) {
453 * There are more than 64k sections,
454 * read count from .sh_size.
456 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
459 info->num_sections = hdr->e_shnum;
461 if (hdr->e_shstrndx == SHN_XINDEX) {
462 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
465 info->secindex_strings = hdr->e_shstrndx;
468 /* Fix endianness in section headers */
469 for (i = 0; i < info->num_sections; i++) {
470 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
471 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
472 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
473 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
474 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
475 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
476 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
477 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
478 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
479 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
481 /* Find symbol table. */
482 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
483 for (i = 1; i < info->num_sections; i++) {
485 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
487 if (!nobits && sechdrs[i].sh_offset > info->size) {
488 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
489 "sizeof(*hrd)=%zu\n", filename,
490 (unsigned long)sechdrs[i].sh_offset,
494 secname = secstrings + sechdrs[i].sh_name;
495 if (strcmp(secname, ".modinfo") == 0) {
497 fatal("%s has NOBITS .modinfo\n", filename);
498 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
499 info->modinfo_len = sechdrs[i].sh_size;
500 } else if (strcmp(secname, "__ksymtab") == 0)
501 info->export_sec = i;
502 else if (strcmp(secname, "__ksymtab_unused") == 0)
503 info->export_unused_sec = i;
504 else if (strcmp(secname, "__ksymtab_gpl") == 0)
505 info->export_gpl_sec = i;
506 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
507 info->export_unused_gpl_sec = i;
508 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
509 info->export_gpl_future_sec = i;
511 if (sechdrs[i].sh_type == SHT_SYMTAB) {
512 unsigned int sh_link_idx;
514 info->symtab_start = (void *)hdr +
515 sechdrs[i].sh_offset;
516 info->symtab_stop = (void *)hdr +
517 sechdrs[i].sh_offset + sechdrs[i].sh_size;
518 sh_link_idx = sechdrs[i].sh_link;
519 info->strtab = (void *)hdr +
520 sechdrs[sh_link_idx].sh_offset;
523 /* 32bit section no. table? ("more than 64k sections") */
524 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
525 symtab_shndx_idx = i;
526 info->symtab_shndx_start = (void *)hdr +
527 sechdrs[i].sh_offset;
528 info->symtab_shndx_stop = (void *)hdr +
529 sechdrs[i].sh_offset + sechdrs[i].sh_size;
532 if (!info->symtab_start)
533 fatal("%s has no symtab?\n", filename);
535 /* Fix endianness in symbols */
536 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
537 sym->st_shndx = TO_NATIVE(sym->st_shndx);
538 sym->st_name = TO_NATIVE(sym->st_name);
539 sym->st_value = TO_NATIVE(sym->st_value);
540 sym->st_size = TO_NATIVE(sym->st_size);
543 if (symtab_shndx_idx != ~0U) {
545 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
546 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
547 filename, sechdrs[symtab_shndx_idx].sh_link,
550 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
558 static void parse_elf_finish(struct elf_info *info)
560 release_file(info->hdr, info->size);
563 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
565 /* ignore __this_module, it will be resolved shortly */
566 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
568 /* ignore global offset table */
569 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
571 if (info->hdr->e_machine == EM_PPC)
572 /* Special register function linked on all modules during final link of .ko */
573 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
574 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
575 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
576 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
577 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
578 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
580 if (info->hdr->e_machine == EM_PPC64)
581 /* Special register function linked on all modules during final link of .ko */
582 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
583 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
584 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
585 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
587 /* Do not ignore this symbol */
591 #define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
592 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
594 static void handle_modversions(struct module *mod, struct elf_info *info,
595 Elf_Sym *sym, const char *symname)
600 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
601 strncmp(symname, "__ksymtab", 9) == 0)
602 export = export_from_secname(info, get_secindex(info, sym));
604 export = export_from_sec(info, get_secindex(info, sym));
606 switch (sym->st_shndx) {
608 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
612 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
613 crc = (unsigned int) sym->st_value;
614 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
619 /* undefined symbol */
620 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
621 ELF_ST_BIND(sym->st_info) != STB_WEAK)
623 if (ignore_undef_symbol(info, symname))
625 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
626 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
627 /* add compatibility with older glibc */
628 #ifndef STT_SPARC_REGISTER
629 #define STT_SPARC_REGISTER STT_REGISTER
631 if (info->hdr->e_machine == EM_SPARC ||
632 info->hdr->e_machine == EM_SPARCV9) {
633 /* Ignore register directives. */
634 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
636 if (symname[0] == '.') {
637 char *munged = strdup(symname);
639 munged[1] = toupper(munged[1]);
645 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
646 if (symname[0] != '_')
651 mod->unres = alloc_symbol(symname,
652 ELF_ST_BIND(sym->st_info) == STB_WEAK,
656 /* All exported symbols */
657 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
658 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
661 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
663 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
664 mod->has_cleanup = 1;
670 * Parse tag=value strings from .modinfo section
672 static char *next_string(char *string, unsigned long *secsize)
674 /* Skip non-zero chars */
677 if ((*secsize)-- <= 1)
681 /* Skip any zero padding. */
684 if ((*secsize)-- <= 1)
690 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
691 const char *tag, char *info)
694 unsigned int taglen = strlen(tag);
695 unsigned long size = modinfo_len;
698 size -= info - (char *)modinfo;
699 modinfo = next_string(info, &size);
702 for (p = modinfo; p; p = next_string(p, &size)) {
703 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
704 return p + taglen + 1;
709 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
713 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
717 * Test if string s ends in string sub
720 static int strrcmp(const char *s, const char *sub)
728 sublen = strlen(sub);
730 if ((slen == 0) || (sublen == 0))
736 return memcmp(s + slen - sublen, sub, sublen);
739 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
742 return elf->strtab + sym->st_name;
747 static const char *sec_name(struct elf_info *elf, int secindex)
749 Elf_Shdr *sechdrs = elf->sechdrs;
750 return (void *)elf->hdr +
751 elf->sechdrs[elf->secindex_strings].sh_offset +
752 sechdrs[secindex].sh_name;
755 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
757 return (void *)elf->hdr +
758 elf->sechdrs[elf->secindex_strings].sh_offset +
762 /* if sym is empty or point to a string
763 * like ".[0-9]+" then return 1.
764 * This is the optional prefix added by ld to some sections
766 static int number_prefix(const char *sym)
774 if (c < '0' || c > '9')
780 /* The pattern is an array of simple patterns.
781 * "foo" will match an exact string equal to "foo"
782 * "*foo" will match a string that ends with "foo"
783 * "foo*" will match a string that begins with "foo"
784 * "foo$" will match a string equal to "foo" or "foo.1"
785 * where the '1' can be any number including several digits.
786 * The $ syntax is for sections where ld append a dot number
787 * to make section name unique.
789 static int match(const char *sym, const char * const pat[])
794 const char *endp = p + strlen(p) - 1;
798 if (strrcmp(sym, p + 1) == 0)
802 else if (*endp == '*') {
803 if (strncmp(sym, p, strlen(p) - 1) == 0)
807 else if (*endp == '$') {
808 if (strncmp(sym, p, strlen(p) - 1) == 0) {
809 if (number_prefix(sym + strlen(p) - 1))
815 if (strcmp(p, sym) == 0)
823 /* sections that we do not want to do full section mismatch check on */
824 static const char *section_white_list[] =
828 ".zdebug*", /* Compressed debug sections. */
829 ".GCC-command-line", /* mn10300 */
830 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
831 ".mdebug*", /* alpha, score, mips etc. */
832 ".pdr", /* alpha, score, mips etc. */
837 ".xt.prop", /* xtensa */
838 ".xt.lit", /* xtensa */
839 ".arcextmap*", /* arc */
840 ".gnu.linkonce.arcext*", /* arc : modules */
845 * This is used to find sections missing the SHF_ALLOC flag.
846 * The cause of this is often a section specified in assembler
847 * without "ax" / "aw".
849 static void check_section(const char *modname, struct elf_info *elf,
852 const char *sec = sech_name(elf, sechdr);
854 if (sechdr->sh_type == SHT_PROGBITS &&
855 !(sechdr->sh_flags & SHF_ALLOC) &&
856 !match(sec, section_white_list)) {
857 warn("%s (%s): unexpected non-allocatable section.\n"
858 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
859 "Note that for example <linux/init.h> contains\n"
860 "section definitions for use in .S files.\n\n",
867 #define ALL_INIT_DATA_SECTIONS \
868 ".init.setup$", ".init.rodata$", \
869 ".cpuinit.rodata$", ".meminit.rodata$", \
870 ".init.data$", ".cpuinit.data$", ".meminit.data$"
871 #define ALL_EXIT_DATA_SECTIONS \
872 ".exit.data$", ".cpuexit.data$", ".memexit.data$"
874 #define ALL_INIT_TEXT_SECTIONS \
875 ".init.text$", ".cpuinit.text$", ".meminit.text$"
876 #define ALL_EXIT_TEXT_SECTIONS \
877 ".exit.text$", ".cpuexit.text$", ".memexit.text$"
879 #define ALL_PCI_INIT_SECTIONS \
880 ".pci_fixup_early$", ".pci_fixup_header$", ".pci_fixup_final$", \
881 ".pci_fixup_enable$", ".pci_fixup_resume$", \
882 ".pci_fixup_resume_early$", ".pci_fixup_suspend$"
884 #define ALL_XXXINIT_SECTIONS CPU_INIT_SECTIONS, MEM_INIT_SECTIONS
885 #define ALL_XXXEXIT_SECTIONS CPU_EXIT_SECTIONS, MEM_EXIT_SECTIONS
887 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
888 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
890 #define DATA_SECTIONS ".data$", ".data.rel$"
891 #define TEXT_SECTIONS ".text$"
893 #define INIT_SECTIONS ".init.*"
894 #define CPU_INIT_SECTIONS ".cpuinit.*"
895 #define MEM_INIT_SECTIONS ".meminit.*"
897 #define EXIT_SECTIONS ".exit.*"
898 #define CPU_EXIT_SECTIONS ".cpuexit.*"
899 #define MEM_EXIT_SECTIONS ".memexit.*"
901 /* init data sections */
902 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
904 /* all init sections */
905 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
907 /* All init and exit sections (code + data) */
908 static const char *init_exit_sections[] =
909 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
912 static const char *data_sections[] = { DATA_SECTIONS, NULL };
915 /* symbols in .data that may refer to init/exit sections */
916 #define DEFAULT_SYMBOL_WHITE_LIST \
918 "*_template", /* scsi uses *_template a lot */ \
919 "*_timer", /* arm uses ops structures named _timer a lot */ \
920 "*_sht", /* scsi also used *_sht to some extent */ \
926 static const char *head_sections[] = { ".head.text*", NULL };
927 static const char *linker_symbols[] =
928 { "__init_begin", "_sinittext", "_einittext", NULL };
935 XXXINIT_TO_SOME_INIT,
936 XXXEXIT_TO_SOME_EXIT,
937 ANY_INIT_TO_ANY_EXIT,
938 ANY_EXIT_TO_ANY_INIT,
942 struct sectioncheck {
943 const char *fromsec[20];
944 const char *tosec[20];
945 enum mismatch mismatch;
946 const char *symbol_white_list[20];
949 const struct sectioncheck sectioncheck[] = {
950 /* Do not reference init/exit code/data from
951 * normal code and data
954 .fromsec = { TEXT_SECTIONS, NULL },
955 .tosec = { ALL_INIT_SECTIONS, NULL },
956 .mismatch = TEXT_TO_ANY_INIT,
957 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
960 .fromsec = { DATA_SECTIONS, NULL },
961 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
962 .mismatch = DATA_TO_ANY_INIT,
963 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
966 .fromsec = { DATA_SECTIONS, NULL },
967 .tosec = { INIT_SECTIONS, NULL },
968 .mismatch = DATA_TO_ANY_INIT,
969 .symbol_white_list = {
970 "*_template", "*_timer", "*_sht", "*_ops",
971 "*_probe", "*_probe_one", "*_console", NULL
975 .fromsec = { TEXT_SECTIONS, NULL },
976 .tosec = { ALL_EXIT_SECTIONS, NULL },
977 .mismatch = TEXT_TO_ANY_EXIT,
978 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
981 .fromsec = { DATA_SECTIONS, NULL },
982 .tosec = { ALL_EXIT_SECTIONS, NULL },
983 .mismatch = DATA_TO_ANY_EXIT,
984 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
986 /* Do not reference init code/data from cpuinit/meminit code/data */
988 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
989 .tosec = { INIT_SECTIONS, NULL },
990 .mismatch = XXXINIT_TO_SOME_INIT,
991 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
993 /* Do not reference cpuinit code/data from meminit code/data */
995 .fromsec = { MEM_INIT_SECTIONS, NULL },
996 .tosec = { CPU_INIT_SECTIONS, NULL },
997 .mismatch = XXXINIT_TO_SOME_INIT,
998 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1000 /* Do not reference meminit code/data from cpuinit code/data */
1002 .fromsec = { CPU_INIT_SECTIONS, NULL },
1003 .tosec = { MEM_INIT_SECTIONS, NULL },
1004 .mismatch = XXXINIT_TO_SOME_INIT,
1005 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1007 /* Do not reference exit code/data from cpuexit/memexit code/data */
1009 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1010 .tosec = { EXIT_SECTIONS, NULL },
1011 .mismatch = XXXEXIT_TO_SOME_EXIT,
1012 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1014 /* Do not reference cpuexit code/data from memexit code/data */
1016 .fromsec = { MEM_EXIT_SECTIONS, NULL },
1017 .tosec = { CPU_EXIT_SECTIONS, NULL },
1018 .mismatch = XXXEXIT_TO_SOME_EXIT,
1019 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1021 /* Do not reference memexit code/data from cpuexit code/data */
1023 .fromsec = { CPU_EXIT_SECTIONS, NULL },
1024 .tosec = { MEM_EXIT_SECTIONS, NULL },
1025 .mismatch = XXXEXIT_TO_SOME_EXIT,
1026 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1028 /* Do not use exit code/data from init code */
1030 .fromsec = { ALL_INIT_SECTIONS, NULL },
1031 .tosec = { ALL_EXIT_SECTIONS, NULL },
1032 .mismatch = ANY_INIT_TO_ANY_EXIT,
1033 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1035 /* Do not use init code/data from exit code */
1037 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1038 .tosec = { ALL_INIT_SECTIONS, NULL },
1039 .mismatch = ANY_EXIT_TO_ANY_INIT,
1040 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1043 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1044 .tosec = { INIT_SECTIONS, NULL },
1045 .mismatch = ANY_INIT_TO_ANY_EXIT,
1046 .symbol_white_list = { NULL },
1048 /* Do not export init/exit functions or data */
1050 .fromsec = { "__ksymtab*", NULL },
1051 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1052 .mismatch = EXPORT_TO_INIT_EXIT,
1053 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1057 static const struct sectioncheck *section_mismatch(
1058 const char *fromsec, const char *tosec)
1061 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1062 const struct sectioncheck *check = §ioncheck[0];
1064 for (i = 0; i < elems; i++) {
1065 if (match(fromsec, check->fromsec) &&
1066 match(tosec, check->tosec))
1074 * Whitelist to allow certain references to pass with no warning.
1077 * If a module parameter is declared __initdata and permissions=0
1078 * then this is legal despite the warning generated.
1079 * We cannot see value of permissions here, so just ignore
1081 * The pattern is identified by:
1082 * tosec = .init.data
1087 * module_param_call() ops can refer to __init set function if permissions=0
1088 * The pattern is identified by:
1089 * tosec = .init.text
1091 * atsym = __param_ops_*
1094 * Many drivers utilise a *driver container with references to
1095 * add, remove, probe functions etc.
1096 * These functions may often be marked __cpuinit and we do not want to
1098 * the pattern is identified by:
1099 * tosec = init or exit section
1100 * fromsec = data section
1101 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1102 * *probe_one, *_console, *_timer
1105 * Whitelist all references from .head.text to any init section
1108 * Some symbols belong to init section but still it is ok to reference
1109 * these from non-init sections as these symbols don't have any memory
1110 * allocated for them and symbol address and value are same. So even
1111 * if init section is freed, its ok to reference those symbols.
1112 * For ex. symbols marking the init section boundaries.
1113 * This pattern is identified by
1114 * refsymname = __init_begin, _sinittext, _einittext
1117 static int secref_whitelist(const struct sectioncheck *mismatch,
1118 const char *fromsec, const char *fromsym,
1119 const char *tosec, const char *tosym)
1121 /* Check for pattern 1 */
1122 if (match(tosec, init_data_sections) &&
1123 match(fromsec, data_sections) &&
1124 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1127 /* Check for pattern 1a */
1128 if (strcmp(tosec, ".init.text") == 0 &&
1129 match(fromsec, data_sections) &&
1130 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1133 /* Check for pattern 2 */
1134 if (match(tosec, init_exit_sections) &&
1135 match(fromsec, data_sections) &&
1136 match(fromsym, mismatch->symbol_white_list))
1139 /* Check for pattern 3 */
1140 if (match(fromsec, head_sections) &&
1141 match(tosec, init_sections))
1144 /* Check for pattern 4 */
1145 if (match(tosym, linker_symbols))
1152 * Find symbol based on relocation record info.
1153 * In some cases the symbol supplied is a valid symbol so
1154 * return refsym. If st_name != 0 we assume this is a valid symbol.
1155 * In other cases the symbol needs to be looked up in the symbol table
1156 * based on section and address.
1158 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1162 Elf_Sym *near = NULL;
1163 Elf64_Sword distance = 20;
1165 unsigned int relsym_secindex;
1167 if (relsym->st_name != 0)
1170 relsym_secindex = get_secindex(elf, relsym);
1171 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1172 if (get_secindex(elf, sym) != relsym_secindex)
1174 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1176 if (sym->st_value == addr)
1178 /* Find a symbol nearby - addr are maybe negative */
1179 d = sym->st_value - addr;
1181 d = addr - sym->st_value;
1187 /* We need a close match */
1194 static inline int is_arm_mapping_symbol(const char *str)
1196 return str[0] == '$' && strchr("atd", str[1])
1197 && (str[2] == '\0' || str[2] == '.');
1201 * If there's no name there, ignore it; likewise, ignore it if it's
1202 * one of the magic symbols emitted used by current ARM tools.
1204 * Otherwise if find_symbols_between() returns those symbols, they'll
1205 * fail the whitelist tests and cause lots of false alarms ... fixable
1206 * only by merging __exit and __init sections into __text, bloating
1207 * the kernel (which is especially evil on embedded platforms).
1209 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1211 const char *name = elf->strtab + sym->st_name;
1213 if (!name || !strlen(name))
1215 return !is_arm_mapping_symbol(name);
1219 * Find symbols before or equal addr and after addr - in the section sec.
1220 * If we find two symbols with equal offset prefer one with a valid name.
1221 * The ELF format may have a better way to detect what type of symbol
1222 * it is, but this works for now.
1224 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1228 Elf_Sym *near = NULL;
1229 Elf_Addr distance = ~0;
1231 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1234 if (is_shndx_special(sym->st_shndx))
1236 symsec = sec_name(elf, get_secindex(elf, sym));
1237 if (strcmp(symsec, sec) != 0)
1239 if (!is_valid_name(elf, sym))
1241 if (sym->st_value <= addr) {
1242 if ((addr - sym->st_value) < distance) {
1243 distance = addr - sym->st_value;
1245 } else if ((addr - sym->st_value) == distance) {
1254 * Convert a section name to the function/data attribute
1255 * .init.text => __init
1256 * .cpuinit.data => __cpudata
1257 * .memexitconst => __memconst
1260 * The memory of returned value has been allocated on a heap. The user of this
1261 * method should free it after usage.
1263 static char *sec2annotation(const char *s)
1265 if (match(s, init_exit_sections)) {
1266 char *p = malloc(20);
1273 while (*s && *s != '.')
1278 if (strstr(s, "rodata") != NULL)
1279 strcat(p, "const ");
1280 else if (strstr(s, "data") != NULL)
1290 static int is_function(Elf_Sym *sym)
1293 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1298 static void print_section_list(const char * const list[20])
1300 const char *const *s = list;
1303 fprintf(stderr, "%s", *s);
1306 fprintf(stderr, ", ");
1308 fprintf(stderr, "\n");
1312 * Print a warning about a section mismatch.
1313 * Try to find symbols near it so user can find it.
1314 * Check whitelist before warning - it may be a false positive.
1316 static void report_sec_mismatch(const char *modname,
1317 const struct sectioncheck *mismatch,
1318 const char *fromsec,
1319 unsigned long long fromaddr,
1320 const char *fromsym,
1322 const char *tosec, const char *tosym,
1325 const char *from, *from_p;
1326 const char *to, *to_p;
1330 switch (from_is_func) {
1331 case 0: from = "variable"; from_p = ""; break;
1332 case 1: from = "function"; from_p = "()"; break;
1333 default: from = "(unknown reference)"; from_p = ""; break;
1335 switch (to_is_func) {
1336 case 0: to = "variable"; to_p = ""; break;
1337 case 1: to = "function"; to_p = "()"; break;
1338 default: to = "(unknown reference)"; to_p = ""; break;
1341 sec_mismatch_count++;
1342 if (!sec_mismatch_verbose)
1345 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1346 "to the %s %s:%s%s\n",
1347 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1350 switch (mismatch->mismatch) {
1351 case TEXT_TO_ANY_INIT:
1352 prl_from = sec2annotation(fromsec);
1353 prl_to = sec2annotation(tosec);
1355 "The function %s%s() references\n"
1357 "This is often because %s lacks a %s\n"
1358 "annotation or the annotation of %s is wrong.\n",
1360 to, prl_to, tosym, to_p,
1361 fromsym, prl_to, tosym);
1365 case DATA_TO_ANY_INIT: {
1366 prl_to = sec2annotation(tosec);
1368 "The variable %s references\n"
1370 "If the reference is valid then annotate the\n"
1371 "variable with __init* or __refdata (see linux/init.h) "
1372 "or name the variable:\n",
1373 fromsym, to, prl_to, tosym, to_p);
1374 print_section_list(mismatch->symbol_white_list);
1378 case TEXT_TO_ANY_EXIT:
1379 prl_to = sec2annotation(tosec);
1381 "The function %s() references a %s in an exit section.\n"
1382 "Often the %s %s%s has valid usage outside the exit section\n"
1383 "and the fix is to remove the %sannotation of %s.\n",
1384 fromsym, to, to, tosym, to_p, prl_to, tosym);
1387 case DATA_TO_ANY_EXIT: {
1388 prl_to = sec2annotation(tosec);
1390 "The variable %s references\n"
1392 "If the reference is valid then annotate the\n"
1393 "variable with __exit* (see linux/init.h) or "
1394 "name the variable:\n",
1395 fromsym, to, prl_to, tosym, to_p);
1396 print_section_list(mismatch->symbol_white_list);
1400 case XXXINIT_TO_SOME_INIT:
1401 case XXXEXIT_TO_SOME_EXIT:
1402 prl_from = sec2annotation(fromsec);
1403 prl_to = sec2annotation(tosec);
1405 "The %s %s%s%s references\n"
1407 "If %s is only used by %s then\n"
1408 "annotate %s with a matching annotation.\n",
1409 from, prl_from, fromsym, from_p,
1410 to, prl_to, tosym, to_p,
1411 tosym, fromsym, tosym);
1415 case ANY_INIT_TO_ANY_EXIT:
1416 prl_from = sec2annotation(fromsec);
1417 prl_to = sec2annotation(tosec);
1419 "The %s %s%s%s references\n"
1421 "This is often seen when error handling "
1422 "in the init function\n"
1423 "uses functionality in the exit path.\n"
1424 "The fix is often to remove the %sannotation of\n"
1425 "%s%s so it may be used outside an exit section.\n",
1426 from, prl_from, fromsym, from_p,
1427 to, prl_to, tosym, to_p,
1428 prl_to, tosym, to_p);
1432 case ANY_EXIT_TO_ANY_INIT:
1433 prl_from = sec2annotation(fromsec);
1434 prl_to = sec2annotation(tosec);
1436 "The %s %s%s%s references\n"
1438 "This is often seen when error handling "
1439 "in the exit function\n"
1440 "uses functionality in the init path.\n"
1441 "The fix is often to remove the %sannotation of\n"
1442 "%s%s so it may be used outside an init section.\n",
1443 from, prl_from, fromsym, from_p,
1444 to, prl_to, tosym, to_p,
1445 prl_to, tosym, to_p);
1449 case EXPORT_TO_INIT_EXIT:
1450 prl_to = sec2annotation(tosec);
1452 "The symbol %s is exported and annotated %s\n"
1453 "Fix this by removing the %sannotation of %s "
1454 "or drop the export.\n",
1455 tosym, prl_to, prl_to, tosym);
1459 fprintf(stderr, "\n");
1462 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1463 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1466 const struct sectioncheck *mismatch;
1468 tosec = sec_name(elf, get_secindex(elf, sym));
1469 mismatch = section_mismatch(fromsec, tosec);
1474 const char *fromsym;
1476 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1477 fromsym = sym_name(elf, from);
1478 to = find_elf_symbol(elf, r->r_addend, sym);
1479 tosym = sym_name(elf, to);
1481 /* check whitelist - we may ignore it */
1482 if (secref_whitelist(mismatch,
1483 fromsec, fromsym, tosec, tosym)) {
1484 report_sec_mismatch(modname, mismatch,
1485 fromsec, r->r_offset, fromsym,
1486 is_function(from), tosec, tosym,
1492 static unsigned int *reloc_location(struct elf_info *elf,
1493 Elf_Shdr *sechdr, Elf_Rela *r)
1495 Elf_Shdr *sechdrs = elf->sechdrs;
1496 int section = sechdr->sh_info;
1498 return (void *)elf->hdr + sechdrs[section].sh_offset +
1502 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1504 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1505 unsigned int *location = reloc_location(elf, sechdr, r);
1509 r->r_addend = TO_NATIVE(*location);
1512 r->r_addend = TO_NATIVE(*location) + 4;
1513 /* For CONFIG_RELOCATABLE=y */
1514 if (elf->hdr->e_type == ET_EXEC)
1515 r->r_addend += r->r_offset;
1522 #define R_ARM_CALL 28
1524 #ifndef R_ARM_JUMP24
1525 #define R_ARM_JUMP24 29
1528 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1530 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1534 /* From ARM ABI: (S + A) | T */
1535 r->r_addend = (int)(long)
1536 (elf->symtab_start + ELF_R_SYM(r->r_info));
1541 /* From ARM ABI: ((S + A) | T) - P */
1542 r->r_addend = (int)(long)(elf->hdr +
1544 (r->r_offset - sechdr->sh_addr));
1552 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1554 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1555 unsigned int *location = reloc_location(elf, sechdr, r);
1558 if (r_typ == R_MIPS_HI16)
1559 return 1; /* skip this */
1560 inst = TO_NATIVE(*location);
1563 r->r_addend = inst & 0xffff;
1566 r->r_addend = (inst & 0x03ffffff) << 2;
1575 static void section_rela(const char *modname, struct elf_info *elf,
1582 const char *fromsec;
1584 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1585 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1587 fromsec = sech_name(elf, sechdr);
1588 fromsec += strlen(".rela");
1589 /* if from section (name) is know good then skip it */
1590 if (match(fromsec, section_white_list))
1593 for (rela = start; rela < stop; rela++) {
1594 r.r_offset = TO_NATIVE(rela->r_offset);
1595 #if KERNEL_ELFCLASS == ELFCLASS64
1596 if (elf->hdr->e_machine == EM_MIPS) {
1598 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1599 r_sym = TO_NATIVE(r_sym);
1600 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1601 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1603 r.r_info = TO_NATIVE(rela->r_info);
1604 r_sym = ELF_R_SYM(r.r_info);
1607 r.r_info = TO_NATIVE(rela->r_info);
1608 r_sym = ELF_R_SYM(r.r_info);
1610 r.r_addend = TO_NATIVE(rela->r_addend);
1611 sym = elf->symtab_start + r_sym;
1612 /* Skip special sections */
1613 if (is_shndx_special(sym->st_shndx))
1615 check_section_mismatch(modname, elf, &r, sym, fromsec);
1619 static void section_rel(const char *modname, struct elf_info *elf,
1626 const char *fromsec;
1628 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1629 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1631 fromsec = sech_name(elf, sechdr);
1632 fromsec += strlen(".rel");
1633 /* if from section (name) is know good then skip it */
1634 if (match(fromsec, section_white_list))
1637 for (rel = start; rel < stop; rel++) {
1638 r.r_offset = TO_NATIVE(rel->r_offset);
1639 #if KERNEL_ELFCLASS == ELFCLASS64
1640 if (elf->hdr->e_machine == EM_MIPS) {
1642 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1643 r_sym = TO_NATIVE(r_sym);
1644 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1645 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1647 r.r_info = TO_NATIVE(rel->r_info);
1648 r_sym = ELF_R_SYM(r.r_info);
1651 r.r_info = TO_NATIVE(rel->r_info);
1652 r_sym = ELF_R_SYM(r.r_info);
1655 switch (elf->hdr->e_machine) {
1657 if (addend_386_rel(elf, sechdr, &r))
1661 if (addend_arm_rel(elf, sechdr, &r))
1665 if (addend_mips_rel(elf, sechdr, &r))
1669 sym = elf->symtab_start + r_sym;
1670 /* Skip special sections */
1671 if (is_shndx_special(sym->st_shndx))
1673 check_section_mismatch(modname, elf, &r, sym, fromsec);
1678 * A module includes a number of sections that are discarded
1679 * either when loaded or when used as built-in.
1680 * For loaded modules all functions marked __init and all data
1681 * marked __initdata will be discarded when the module has been initialized.
1682 * Likewise for modules used built-in the sections marked __exit
1683 * are discarded because __exit marked function are supposed to be called
1684 * only when a module is unloaded which never happens for built-in modules.
1685 * The check_sec_ref() function traverses all relocation records
1686 * to find all references to a section that reference a section that will
1687 * be discarded and warns about it.
1689 static void check_sec_ref(struct module *mod, const char *modname,
1690 struct elf_info *elf)
1693 Elf_Shdr *sechdrs = elf->sechdrs;
1695 /* Walk through all sections */
1696 for (i = 0; i < elf->num_sections; i++) {
1697 check_section(modname, elf, &elf->sechdrs[i]);
1698 /* We want to process only relocation sections and not .init */
1699 if (sechdrs[i].sh_type == SHT_RELA)
1700 section_rela(modname, elf, &elf->sechdrs[i]);
1701 else if (sechdrs[i].sh_type == SHT_REL)
1702 section_rel(modname, elf, &elf->sechdrs[i]);
1706 static void read_symbols(char *modname)
1708 const char *symname;
1712 struct elf_info info = { };
1715 if (!parse_elf(&info, modname))
1718 mod = new_module(modname);
1720 /* When there's no vmlinux, don't print warnings about
1721 * unresolved symbols (since there'll be too many ;) */
1722 if (is_vmlinux(modname)) {
1727 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1728 if (info.modinfo && !license && !is_vmlinux(modname))
1729 warn("modpost: missing MODULE_LICENSE() in %s\n"
1730 "see include/linux/module.h for "
1731 "more information\n", modname);
1733 if (license_is_gpl_compatible(license))
1734 mod->gpl_compatible = 1;
1736 mod->gpl_compatible = 0;
1739 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1740 "license", license);
1743 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1744 symname = info.strtab + sym->st_name;
1746 handle_modversions(mod, &info, sym, symname);
1747 handle_moddevtable(mod, &info, sym, symname);
1749 if (!is_vmlinux(modname) ||
1750 (is_vmlinux(modname) && vmlinux_section_warnings))
1751 check_sec_ref(mod, modname, &info);
1753 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1755 maybe_frob_rcs_version(modname, version, info.modinfo,
1756 version - (char *)info.hdr);
1757 if (version || (all_versions && !is_vmlinux(modname)))
1758 get_src_version(modname, mod->srcversion,
1759 sizeof(mod->srcversion)-1);
1761 parse_elf_finish(&info);
1763 /* Our trick to get versioning for module struct etc. - it's
1764 * never passed as an argument to an exported function, so
1765 * the automatic versioning doesn't pick it up, but it's really
1766 * important anyhow */
1768 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1771 static void read_symbols_from_files(const char *filename)
1774 char fname[PATH_MAX];
1776 if (strcmp(filename, "-") != 0) {
1777 in = fopen(filename, "r");
1779 fatal("Can't open filenames file %s: %m", filename);
1782 while (fgets(fname, PATH_MAX, in) != NULL) {
1783 if (strends(fname, "\n"))
1784 fname[strlen(fname)-1] = '\0';
1785 read_symbols(fname);
1794 /* We first write the generated file into memory using the
1795 * following helper, then compare to the file on disk and
1796 * only update the later if anything changed */
1798 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1799 const char *fmt, ...)
1806 len = vsnprintf(tmp, SZ, fmt, ap);
1807 buf_write(buf, tmp, len);
1811 void buf_write(struct buffer *buf, const char *s, int len)
1813 if (buf->size - buf->pos < len) {
1814 buf->size += len + SZ;
1815 buf->p = realloc(buf->p, buf->size);
1817 strncpy(buf->p + buf->pos, s, len);
1821 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1823 const char *e = is_vmlinux(m) ?"":".ko";
1827 fatal("modpost: GPL-incompatible module %s%s "
1828 "uses GPL-only symbol '%s'\n", m, e, s);
1830 case export_unused_gpl:
1831 fatal("modpost: GPL-incompatible module %s%s "
1832 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1834 case export_gpl_future:
1835 warn("modpost: GPL-incompatible module %s%s "
1836 "uses future GPL-only symbol '%s'\n", m, e, s);
1840 case export_unknown:
1846 static void check_for_unused(enum export exp, const char *m, const char *s)
1848 const char *e = is_vmlinux(m) ?"":".ko";
1852 case export_unused_gpl:
1853 warn("modpost: module %s%s "
1854 "uses symbol '%s' marked UNUSED\n", m, e, s);
1862 static void check_exports(struct module *mod)
1864 struct symbol *s, *exp;
1866 for (s = mod->unres; s; s = s->next) {
1867 const char *basename;
1868 exp = find_symbol(s->name);
1869 if (!exp || exp->module == mod)
1871 basename = strrchr(mod->name, '/');
1875 basename = mod->name;
1876 if (!mod->gpl_compatible)
1877 check_for_gpl_usage(exp->export, basename, exp->name);
1878 check_for_unused(exp->export, basename, exp->name);
1883 * Header for the generated file
1885 static void add_header(struct buffer *b, struct module *mod)
1887 buf_printf(b, "#include <linux/module.h>\n");
1888 buf_printf(b, "#include <linux/vermagic.h>\n");
1889 buf_printf(b, "#include <linux/compiler.h>\n");
1890 buf_printf(b, "\n");
1891 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1892 buf_printf(b, "\n");
1893 buf_printf(b, "struct module __this_module\n");
1894 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1895 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1897 buf_printf(b, "\t.init = init_module,\n");
1898 if (mod->has_cleanup)
1899 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1900 "\t.exit = cleanup_module,\n"
1902 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1903 buf_printf(b, "};\n");
1906 static void add_intree_flag(struct buffer *b, int is_intree)
1909 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1912 static void add_staging_flag(struct buffer *b, const char *name)
1914 static const char *staging_dir = "drivers/staging";
1916 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1917 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1921 * Record CRCs for unresolved symbols
1923 static int add_versions(struct buffer *b, struct module *mod)
1925 struct symbol *s, *exp;
1928 for (s = mod->unres; s; s = s->next) {
1929 exp = find_symbol(s->name);
1930 if (!exp || exp->module == mod) {
1931 if (have_vmlinux && !s->weak) {
1932 if (warn_unresolved) {
1933 warn("\"%s\" [%s.ko] undefined!\n",
1934 s->name, mod->name);
1936 merror("\"%s\" [%s.ko] undefined!\n",
1937 s->name, mod->name);
1943 s->module = exp->module;
1944 s->crc_valid = exp->crc_valid;
1951 buf_printf(b, "\n");
1952 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1953 buf_printf(b, "__used\n");
1954 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1956 for (s = mod->unres; s; s = s->next) {
1959 if (!s->crc_valid) {
1960 warn("\"%s\" [%s.ko] has no CRC!\n",
1961 s->name, mod->name);
1964 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
1968 buf_printf(b, "};\n");
1973 static void add_depends(struct buffer *b, struct module *mod,
1974 struct module *modules)
1980 for (m = modules; m; m = m->next)
1981 m->seen = is_vmlinux(m->name);
1983 buf_printf(b, "\n");
1984 buf_printf(b, "static const char __module_depends[]\n");
1985 buf_printf(b, "__used\n");
1986 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1987 buf_printf(b, "\"depends=");
1988 for (s = mod->unres; s; s = s->next) {
1993 if (s->module->seen)
1996 s->module->seen = 1;
1997 p = strrchr(s->module->name, '/');
2001 p = s->module->name;
2002 buf_printf(b, "%s%s", first ? "" : ",", p);
2005 buf_printf(b, "\";\n");
2008 static void add_srcversion(struct buffer *b, struct module *mod)
2010 if (mod->srcversion[0]) {
2011 buf_printf(b, "\n");
2012 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2017 static void write_if_changed(struct buffer *b, const char *fname)
2023 file = fopen(fname, "r");
2027 if (fstat(fileno(file), &st) < 0)
2030 if (st.st_size != b->pos)
2033 tmp = NOFAIL(malloc(b->pos));
2034 if (fread(tmp, 1, b->pos, file) != b->pos)
2037 if (memcmp(tmp, b->p, b->pos) != 0)
2049 file = fopen(fname, "w");
2054 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2061 /* parse Module.symvers file. line format:
2062 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2064 static void read_dump(const char *fname, unsigned int kernel)
2066 unsigned long size, pos = 0;
2067 void *file = grab_file(fname, &size);
2071 /* No symbol versions, silently ignore */
2074 while ((line = get_next_line(&pos, file, size))) {
2075 char *symname, *modname, *d, *export, *end;
2080 if (!(symname = strchr(line, '\t')))
2083 if (!(modname = strchr(symname, '\t')))
2086 if ((export = strchr(modname, '\t')) != NULL)
2088 if (export && ((end = strchr(export, '\t')) != NULL))
2090 crc = strtoul(line, &d, 16);
2091 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2093 mod = find_module(modname);
2095 if (is_vmlinux(modname))
2097 mod = new_module(modname);
2100 s = sym_add_exported(symname, mod, export_no(export));
2103 sym_update_crc(symname, mod, crc, export_no(export));
2107 fatal("parse error in symbol dump file\n");
2110 /* For normal builds always dump all symbols.
2111 * For external modules only dump symbols
2112 * that are not read from kernel Module.symvers.
2114 static int dump_sym(struct symbol *sym)
2116 if (!external_module)
2118 if (sym->vmlinux || sym->kernel)
2123 static void write_dump(const char *fname)
2125 struct buffer buf = { };
2126 struct symbol *symbol;
2129 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2130 symbol = symbolhash[n];
2132 if (dump_sym(symbol))
2133 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2134 symbol->crc, symbol->name,
2135 symbol->module->name,
2136 export_str(symbol->export));
2137 symbol = symbol->next;
2140 write_if_changed(&buf, fname);
2143 struct ext_sym_list {
2144 struct ext_sym_list *next;
2148 int main(int argc, char **argv)
2151 struct buffer buf = { };
2152 char *kernel_read = NULL, *module_read = NULL;
2153 char *dump_write = NULL, *files_source = NULL;
2156 struct ext_sym_list *extsym_iter;
2157 struct ext_sym_list *extsym_start = NULL;
2159 while ((opt = getopt(argc, argv, "i:I:e:msST:o:awM:K:")) != -1) {
2162 kernel_read = optarg;
2165 module_read = optarg;
2166 external_module = 1;
2169 external_module = 1;
2171 NOFAIL(malloc(sizeof(*extsym_iter)));
2172 extsym_iter->next = extsym_start;
2173 extsym_iter->file = optarg;
2174 extsym_start = extsym_iter;
2180 dump_write = optarg;
2186 vmlinux_section_warnings = 0;
2189 sec_mismatch_verbose = 0;
2192 files_source = optarg;
2195 warn_unresolved = 1;
2203 read_dump(kernel_read, 1);
2205 read_dump(module_read, 0);
2206 while (extsym_start) {
2207 read_dump(extsym_start->file, 0);
2208 extsym_iter = extsym_start->next;
2210 extsym_start = extsym_iter;
2213 while (optind < argc)
2214 read_symbols(argv[optind++]);
2217 read_symbols_from_files(files_source);
2219 for (mod = modules; mod; mod = mod->next) {
2227 for (mod = modules; mod; mod = mod->next) {
2228 char fname[strlen(mod->name) + 10];
2235 add_header(&buf, mod);
2236 add_intree_flag(&buf, !external_module);
2237 add_staging_flag(&buf, mod->name);
2238 err |= add_versions(&buf, mod);
2239 add_depends(&buf, mod, modules);
2240 add_moddevtable(&buf, mod);
2241 add_srcversion(&buf, mod);
2243 sprintf(fname, "%s.mod.c", mod->name);
2244 write_if_changed(&buf, fname);
2248 write_dump(dump_write);
2249 if (sec_mismatch_count && !sec_mismatch_verbose)
2250 warn("modpost: Found %d section mismatch(es).\n"
2251 "To see full details build your kernel with:\n"
2252 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2253 sec_mismatch_count);