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 ...
16 #include "../../include/linux/license.h"
18 /* Are we using CONFIG_MODVERSIONS? */
20 /* Warn about undefined symbols? (do so if we have vmlinux) */
22 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
23 static int all_versions = 0;
24 /* If we are modposting external module set to 1 */
25 static int external_module = 0;
26 /* Warn about section mismatch in vmlinux if set to 1 */
27 static int vmlinux_section_warnings = 1;
28 /* Only warn about unresolved symbols */
29 static int warn_unresolved = 0;
30 /* How a symbol is exported */
32 export_plain, export_unused, export_gpl,
33 export_unused_gpl, export_gpl_future, export_unknown
36 #define PRINTF __attribute__ ((format (printf, 1, 2)))
38 PRINTF void fatal(const char *fmt, ...)
42 fprintf(stderr, "FATAL: ");
44 va_start(arglist, fmt);
45 vfprintf(stderr, fmt, arglist);
51 PRINTF void warn(const char *fmt, ...)
55 fprintf(stderr, "WARNING: ");
57 va_start(arglist, fmt);
58 vfprintf(stderr, fmt, arglist);
62 PRINTF void merror(const char *fmt, ...)
66 fprintf(stderr, "ERROR: ");
68 va_start(arglist, fmt);
69 vfprintf(stderr, fmt, arglist);
73 static int is_vmlinux(const char *modname)
77 myname = strrchr(modname, '/');
83 return (strcmp(myname, "vmlinux") == 0) ||
84 (strcmp(myname, "vmlinux.o") == 0);
87 void *do_nofail(void *ptr, const char *expr)
90 fatal("modpost: Memory allocation failure: %s.\n", expr);
95 /* A list of all modules we processed */
96 static struct module *modules;
98 static struct module *find_module(char *modname)
102 for (mod = modules; mod; mod = mod->next)
103 if (strcmp(mod->name, modname) == 0)
108 static struct module *new_module(char *modname)
113 mod = NOFAIL(malloc(sizeof(*mod)));
114 memset(mod, 0, sizeof(*mod));
115 p = NOFAIL(strdup(modname));
117 /* strip trailing .o */
120 if (strcmp(s, ".o") == 0)
125 mod->gpl_compatible = -1;
132 /* A hash of all exported symbols,
133 * struct symbol is also used for lists of unresolved symbols */
135 #define SYMBOL_HASH_SIZE 1024
139 struct module *module;
143 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
144 unsigned int kernel:1; /* 1 if symbol is from kernel
145 * (only for external modules) **/
146 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
147 enum export export; /* Type of export */
151 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
153 /* This is based on the hash agorithm from gdbm, via tdb */
154 static inline unsigned int tdb_hash(const char *name)
156 unsigned value; /* Used to compute the hash value. */
157 unsigned i; /* Used to cycle through random values. */
159 /* Set the initial value from the key size. */
160 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
161 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
163 return (1103515243 * value + 12345);
167 * Allocate a new symbols for use in the hash of exported symbols or
168 * the list of unresolved symbols per module
170 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
173 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
175 memset(s, 0, sizeof(*s));
176 strcpy(s->name, name);
182 /* For the hash of exported symbols */
183 static struct symbol *new_symbol(const char *name, struct module *module,
189 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
190 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
191 new->module = module;
192 new->export = export;
196 static struct symbol *find_symbol(const char *name)
200 /* For our purposes, .foo matches foo. PPC64 needs this. */
204 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
205 if (strcmp(s->name, name) == 0)
215 { .str = "EXPORT_SYMBOL", .export = export_plain },
216 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
217 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
218 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
219 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
220 { .str = "(unknown)", .export = export_unknown },
224 static const char *export_str(enum export ex)
226 return export_list[ex].str;
229 static enum export export_no(const char *s)
234 return export_unknown;
235 for (i = 0; export_list[i].export != export_unknown; i++) {
236 if (strcmp(export_list[i].str, s) == 0)
237 return export_list[i].export;
239 return export_unknown;
242 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
244 if (sec == elf->export_sec)
246 else if (sec == elf->export_unused_sec)
247 return export_unused;
248 else if (sec == elf->export_gpl_sec)
250 else if (sec == elf->export_unused_gpl_sec)
251 return export_unused_gpl;
252 else if (sec == elf->export_gpl_future_sec)
253 return export_gpl_future;
255 return export_unknown;
259 * Add an exported symbol - it may have already been added without a
260 * CRC, in this case just update the CRC
262 static struct symbol *sym_add_exported(const char *name, struct module *mod,
265 struct symbol *s = find_symbol(name);
268 s = new_symbol(name, mod, export);
271 warn("%s: '%s' exported twice. Previous export "
272 "was in %s%s\n", mod->name, name,
274 is_vmlinux(s->module->name) ?"":".ko");
276 /* In case Modules.symvers was out of date */
281 s->vmlinux = is_vmlinux(mod->name);
287 static void sym_update_crc(const char *name, struct module *mod,
288 unsigned int crc, enum export export)
290 struct symbol *s = find_symbol(name);
293 s = new_symbol(name, mod, export);
298 void *grab_file(const char *filename, unsigned long *size)
304 fd = open(filename, O_RDONLY);
305 if (fd < 0 || fstat(fd, &st) != 0)
309 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
312 if (map == MAP_FAILED)
318 * Return a copy of the next line in a mmap'ed file.
319 * spaces in the beginning of the line is trimmed away.
320 * Return a pointer to a static buffer.
322 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
324 static char line[4096];
327 signed char *p = (signed char *)file + *pos;
330 for (; *pos < size ; (*pos)++) {
331 if (skip && isspace(*p)) {
336 if (*p != '\n' && (*pos < size)) {
340 break; /* Too long, stop */
351 void release_file(void *file, unsigned long size)
356 static int parse_elf(struct elf_info *info, const char *filename)
363 hdr = grab_file(filename, &info->size);
369 if (info->size < sizeof(*hdr)) {
370 /* file too small, assume this is an empty .o file */
373 /* Is this a valid ELF file? */
374 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
375 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
376 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
377 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
378 /* Not an ELF file - silently ignore it */
381 /* Fix endianness in ELF header */
382 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
383 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
384 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
385 hdr->e_machine = TO_NATIVE(hdr->e_machine);
386 hdr->e_type = TO_NATIVE(hdr->e_type);
387 sechdrs = (void *)hdr + hdr->e_shoff;
388 info->sechdrs = sechdrs;
390 /* Check if file offset is correct */
391 if (hdr->e_shoff > info->size) {
392 fatal("section header offset=%lu in file '%s' is bigger than "
393 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
394 filename, info->size);
398 /* Fix endianness in section headers */
399 for (i = 0; i < hdr->e_shnum; i++) {
400 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
401 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
402 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
403 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
404 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
405 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
406 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
408 /* Find symbol table. */
409 for (i = 1; i < hdr->e_shnum; i++) {
410 const char *secstrings
411 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
414 if (sechdrs[i].sh_offset > info->size) {
415 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
416 "sizeof(*hrd)=%zu\n", filename,
417 (unsigned long)sechdrs[i].sh_offset,
421 secname = secstrings + sechdrs[i].sh_name;
422 if (strcmp(secname, ".modinfo") == 0) {
423 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
424 info->modinfo_len = sechdrs[i].sh_size;
425 } else if (strcmp(secname, "__ksymtab") == 0)
426 info->export_sec = i;
427 else if (strcmp(secname, "__ksymtab_unused") == 0)
428 info->export_unused_sec = i;
429 else if (strcmp(secname, "__ksymtab_gpl") == 0)
430 info->export_gpl_sec = i;
431 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
432 info->export_unused_gpl_sec = i;
433 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
434 info->export_gpl_future_sec = i;
436 if (sechdrs[i].sh_type != SHT_SYMTAB)
439 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
440 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
441 + sechdrs[i].sh_size;
442 info->strtab = (void *)hdr +
443 sechdrs[sechdrs[i].sh_link].sh_offset;
445 if (!info->symtab_start)
446 fatal("%s has no symtab?\n", filename);
448 /* Fix endianness in symbols */
449 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
450 sym->st_shndx = TO_NATIVE(sym->st_shndx);
451 sym->st_name = TO_NATIVE(sym->st_name);
452 sym->st_value = TO_NATIVE(sym->st_value);
453 sym->st_size = TO_NATIVE(sym->st_size);
458 static void parse_elf_finish(struct elf_info *info)
460 release_file(info->hdr, info->size);
463 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
464 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
466 static void handle_modversions(struct module *mod, struct elf_info *info,
467 Elf_Sym *sym, const char *symname)
470 enum export export = export_from_sec(info, sym->st_shndx);
472 switch (sym->st_shndx) {
474 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
478 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
479 crc = (unsigned int) sym->st_value;
480 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
485 /* undefined symbol */
486 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
487 ELF_ST_BIND(sym->st_info) != STB_WEAK)
489 /* ignore global offset table */
490 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
492 /* ignore __this_module, it will be resolved shortly */
493 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
495 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
496 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
497 /* add compatibility with older glibc */
498 #ifndef STT_SPARC_REGISTER
499 #define STT_SPARC_REGISTER STT_REGISTER
501 if (info->hdr->e_machine == EM_SPARC ||
502 info->hdr->e_machine == EM_SPARCV9) {
503 /* Ignore register directives. */
504 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
506 if (symname[0] == '.') {
507 char *munged = strdup(symname);
509 munged[1] = toupper(munged[1]);
515 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
516 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
518 alloc_symbol(symname +
519 strlen(MODULE_SYMBOL_PREFIX),
520 ELF_ST_BIND(sym->st_info) == STB_WEAK,
525 /* All exported symbols */
526 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
527 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
530 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
532 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
533 mod->has_cleanup = 1;
539 * Parse tag=value strings from .modinfo section
541 static char *next_string(char *string, unsigned long *secsize)
543 /* Skip non-zero chars */
546 if ((*secsize)-- <= 1)
550 /* Skip any zero padding. */
553 if ((*secsize)-- <= 1)
559 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
560 const char *tag, char *info)
563 unsigned int taglen = strlen(tag);
564 unsigned long size = modinfo_len;
567 size -= info - (char *)modinfo;
568 modinfo = next_string(info, &size);
571 for (p = modinfo; p; p = next_string(p, &size)) {
572 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
573 return p + taglen + 1;
578 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
582 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
586 * Test if string s ends in string sub
589 static int strrcmp(const char *s, const char *sub)
597 sublen = strlen(sub);
599 if ((slen == 0) || (sublen == 0))
605 return memcmp(s + slen - sublen, sub, sublen);
609 * Functions used only during module init is marked __init and is stored in
610 * a .init.text section. Likewise data is marked __initdata and stored in
611 * a .init.data section.
612 * If this section is one of these sections return 1
613 * See include/linux/init.h for the details
615 static int init_section(const char *name)
617 if (strcmp(name, ".init") == 0)
619 if (strncmp(name, ".init.", strlen(".init.")) == 0)
625 * Functions used only during module exit is marked __exit and is stored in
626 * a .exit.text section. Likewise data is marked __exitdata and stored in
627 * a .exit.data section.
628 * If this section is one of these sections return 1
629 * See include/linux/init.h for the details
631 static int exit_section(const char *name)
633 if (strcmp(name, ".exit.text") == 0)
635 if (strcmp(name, ".exit.data") == 0)
642 * Data sections are named like this:
643 * .data | .data.rel | .data.rel.*
644 * Return 1 if the specified section is a data section
646 static int data_section(const char *name)
648 if ((strcmp(name, ".data") == 0) ||
649 (strcmp(name, ".data.rel") == 0) ||
650 (strncmp(name, ".data.rel.", strlen(".data.rel.")) == 0))
657 * Whitelist to allow certain references to pass with no warning.
660 * Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
661 * The pattern is identified by:
662 * fromsec = .text.init.refok* | .data.init.refok*
665 * If a module parameter is declared __initdata and permissions=0
666 * then this is legal despite the warning generated.
667 * We cannot see value of permissions here, so just ignore
669 * The pattern is identified by:
675 * Many drivers utilise a *driver container with references to
676 * add, remove, probe functions etc.
677 * These functions may often be marked __init and we do not want to
679 * the pattern is identified by:
680 * tosec = init or exit section
681 * fromsec = data section
682 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
683 * *probe_one, *_console, *_timer
686 * Whitelist all refereces from .text.head to .init.data
687 * Whitelist all refereces from .text.head to .init.text
690 * Some symbols belong to init section but still it is ok to reference
691 * these from non-init sections as these symbols don't have any memory
692 * allocated for them and symbol address and value are same. So even
693 * if init section is freed, its ok to reference those symbols.
694 * For ex. symbols marking the init section boundaries.
695 * This pattern is identified by
696 * refsymname = __init_begin, _sinittext, _einittext
699 * Xtensa uses literal sections for constants that are accessed PC-relative.
700 * Literal sections may safely reference their text sections.
701 * (Note that the name for the literal section omits any trailing '.text')
702 * tosec = <section>[.text]
703 * fromsec = <section>.literal
705 static int secref_whitelist(const char *modname, const char *tosec,
706 const char *fromsec, const char *atsym,
707 const char *refsymname)
711 const char *pat2sym[] = {
713 "_template", /* scsi uses *_template a lot */
714 "_timer", /* arm uses ops structures named _timer a lot */
715 "_sht", /* scsi also used *_sht to some extent */
723 const char *pat3refsym[] = {
730 /* Check for pattern 0 */
731 if ((strncmp(fromsec, ".text.init.refok", strlen(".text.init.refok")) == 0) ||
732 (strncmp(fromsec, ".exit.text.refok", strlen(".exit.text.refok")) == 0) ||
733 (strncmp(fromsec, ".data.init.refok", strlen(".data.init.refok")) == 0))
736 /* Check for pattern 1 */
737 if ((strcmp(tosec, ".init.data") == 0) &&
738 (strncmp(fromsec, ".data", strlen(".data")) == 0) &&
739 (strncmp(atsym, "__param", strlen("__param")) == 0))
742 /* Check for pattern 2 */
743 if ((init_section(tosec) || exit_section(tosec))
744 && data_section(fromsec))
745 for (s = pat2sym; *s; s++)
746 if (strrcmp(atsym, *s) == 0)
749 /* Check for pattern 3 */
750 if ((strcmp(fromsec, ".text.head") == 0) &&
751 ((strcmp(tosec, ".init.data") == 0) ||
752 (strcmp(tosec, ".init.text") == 0)))
755 /* Check for pattern 4 */
756 for (s = pat3refsym; *s; s++)
757 if (strcmp(refsymname, *s) == 0)
760 /* Check for pattern 5 */
761 if (strrcmp(tosec, ".text") == 0)
762 len = strlen(tosec) - strlen(".text");
765 if ((strncmp(tosec, fromsec, len) == 0) && (strlen(fromsec) > len) &&
766 (strcmp(fromsec + len, ".literal") == 0))
773 * Find symbol based on relocation record info.
774 * In some cases the symbol supplied is a valid symbol so
775 * return refsym. If st_name != 0 we assume this is a valid symbol.
776 * In other cases the symbol needs to be looked up in the symbol table
777 * based on section and address.
779 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
783 Elf_Sym *near = NULL;
784 Elf64_Sword distance = 20;
787 if (relsym->st_name != 0)
789 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
790 if (sym->st_shndx != relsym->st_shndx)
792 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
794 if (sym->st_value == addr)
796 /* Find a symbol nearby - addr are maybe negative */
797 d = sym->st_value - addr;
799 d = addr - sym->st_value;
805 /* We need a close match */
812 static inline int is_arm_mapping_symbol(const char *str)
814 return str[0] == '$' && strchr("atd", str[1])
815 && (str[2] == '\0' || str[2] == '.');
819 * If there's no name there, ignore it; likewise, ignore it if it's
820 * one of the magic symbols emitted used by current ARM tools.
822 * Otherwise if find_symbols_between() returns those symbols, they'll
823 * fail the whitelist tests and cause lots of false alarms ... fixable
824 * only by merging __exit and __init sections into __text, bloating
825 * the kernel (which is especially evil on embedded platforms).
827 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
829 const char *name = elf->strtab + sym->st_name;
831 if (!name || !strlen(name))
833 return !is_arm_mapping_symbol(name);
837 * Find symbols before or equal addr and after addr - in the section sec.
838 * If we find two symbols with equal offset prefer one with a valid name.
839 * The ELF format may have a better way to detect what type of symbol
840 * it is, but this works for now.
842 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
844 Elf_Sym **before, Elf_Sym **after)
847 Elf_Ehdr *hdr = elf->hdr;
848 Elf_Addr beforediff = ~0;
849 Elf_Addr afterdiff = ~0;
850 const char *secstrings = (void *)hdr +
851 elf->sechdrs[hdr->e_shstrndx].sh_offset;
856 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
859 if (sym->st_shndx >= SHN_LORESERVE)
861 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
862 if (strcmp(symsec, sec) != 0)
864 if (!is_valid_name(elf, sym))
866 if (sym->st_value <= addr) {
867 if ((addr - sym->st_value) < beforediff) {
868 beforediff = addr - sym->st_value;
870 } else if ((addr - sym->st_value) == beforediff) {
874 if ((sym->st_value - addr) < afterdiff) {
875 afterdiff = sym->st_value - addr;
877 } else if ((sym->st_value - addr) == afterdiff)
884 * Print a warning about a section mismatch.
885 * Try to find symbols near it so user can find it.
886 * Check whitelist before warning - it may be a false positive.
888 static void warn_sec_mismatch(const char *modname, const char *fromsec,
889 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
891 const char *refsymname = "";
892 Elf_Sym *before, *after;
894 Elf_Ehdr *hdr = elf->hdr;
895 Elf_Shdr *sechdrs = elf->sechdrs;
896 const char *secstrings = (void *)hdr +
897 sechdrs[hdr->e_shstrndx].sh_offset;
898 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
900 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
902 refsym = find_elf_symbol(elf, r.r_addend, sym);
903 if (refsym && strlen(elf->strtab + refsym->st_name))
904 refsymname = elf->strtab + refsym->st_name;
906 /* check whitelist - we may ignore it */
907 if (secref_whitelist(modname, secname, fromsec,
908 before ? elf->strtab + before->st_name : "",
912 if (before && after) {
913 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
914 "(between '%s' and '%s')\n",
915 modname, fromsec, (unsigned long long)r.r_offset,
917 elf->strtab + before->st_name,
918 elf->strtab + after->st_name);
920 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
922 modname, fromsec, (unsigned long long)r.r_offset,
924 elf->strtab + before->st_name);
926 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
927 "before '%s' (at offset -0x%llx)\n",
928 modname, fromsec, (unsigned long long)r.r_offset,
930 elf->strtab + after->st_name,
931 (unsigned long long)r.r_offset);
933 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
934 modname, fromsec, (unsigned long long)r.r_offset,
935 secname, refsymname);
939 static unsigned int *reloc_location(struct elf_info *elf,
940 Elf_Shdr *sechdr, Elf_Rela *r)
942 Elf_Shdr *sechdrs = elf->sechdrs;
943 int section = sechdr->sh_info;
945 return (void *)elf->hdr + sechdrs[section].sh_offset +
946 (r->r_offset - sechdrs[section].sh_addr);
949 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
951 unsigned int r_typ = ELF_R_TYPE(r->r_info);
952 unsigned int *location = reloc_location(elf, sechdr, r);
956 r->r_addend = TO_NATIVE(*location);
959 r->r_addend = TO_NATIVE(*location) + 4;
960 /* For CONFIG_RELOCATABLE=y */
961 if (elf->hdr->e_type == ET_EXEC)
962 r->r_addend += r->r_offset;
968 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
970 unsigned int r_typ = ELF_R_TYPE(r->r_info);
974 /* From ARM ABI: (S + A) | T */
975 r->r_addend = (int)(long)
976 (elf->symtab_start + ELF_R_SYM(r->r_info));
979 /* From ARM ABI: ((S + A) | T) - P */
980 r->r_addend = (int)(long)(elf->hdr +
982 (r->r_offset - sechdr->sh_addr));
990 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
992 unsigned int r_typ = ELF_R_TYPE(r->r_info);
993 unsigned int *location = reloc_location(elf, sechdr, r);
996 if (r_typ == R_MIPS_HI16)
997 return 1; /* skip this */
998 inst = TO_NATIVE(*location);
1001 r->r_addend = inst & 0xffff;
1004 r->r_addend = (inst & 0x03ffffff) << 2;
1013 static void section_rela(const char *modname, struct elf_info *elf,
1014 Elf_Shdr *sechdr, int section(const char *),
1015 int section_ref_ok(const char *))
1021 const char *fromsec;
1024 Elf_Ehdr *hdr = elf->hdr;
1025 Elf_Rela *start = (void *)hdr + sechdr->sh_offset;
1026 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1028 const char *secstrings = (void *)hdr +
1029 elf->sechdrs[hdr->e_shstrndx].sh_offset;
1031 fromsec = secstrings + sechdr->sh_name;
1032 fromsec += strlen(".rela");
1033 /* if from section (name) is know good then skip it */
1034 if (section_ref_ok(fromsec))
1037 for (rela = start; rela < stop; rela++) {
1038 r.r_offset = TO_NATIVE(rela->r_offset);
1039 #if KERNEL_ELFCLASS == ELFCLASS64
1040 if (hdr->e_machine == EM_MIPS) {
1042 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1043 r_sym = TO_NATIVE(r_sym);
1044 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1045 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1047 r.r_info = TO_NATIVE(rela->r_info);
1048 r_sym = ELF_R_SYM(r.r_info);
1051 r.r_info = TO_NATIVE(rela->r_info);
1052 r_sym = ELF_R_SYM(r.r_info);
1054 r.r_addend = TO_NATIVE(rela->r_addend);
1055 sym = elf->symtab_start + r_sym;
1056 /* Skip special sections */
1057 if (sym->st_shndx >= SHN_LORESERVE)
1060 tosec = secstrings +
1061 elf->sechdrs[sym->st_shndx].sh_name;
1063 warn_sec_mismatch(modname, fromsec, elf, sym, r);
1067 static void section_rel(const char *modname, struct elf_info *elf,
1068 Elf_Shdr *sechdr, int section(const char *),
1069 int section_ref_ok(const char *))
1075 const char *fromsec;
1078 Elf_Ehdr *hdr = elf->hdr;
1079 Elf_Rel *start = (void *)hdr + sechdr->sh_offset;
1080 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1082 const char *secstrings = (void *)hdr +
1083 elf->sechdrs[hdr->e_shstrndx].sh_offset;
1085 fromsec = secstrings + sechdr->sh_name;
1086 fromsec += strlen(".rel");
1087 /* if from section (name) is know good then skip it */
1088 if (section_ref_ok(fromsec))
1091 for (rel = start; rel < stop; rel++) {
1092 r.r_offset = TO_NATIVE(rel->r_offset);
1093 #if KERNEL_ELFCLASS == ELFCLASS64
1094 if (hdr->e_machine == EM_MIPS) {
1096 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1097 r_sym = TO_NATIVE(r_sym);
1098 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1099 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1101 r.r_info = TO_NATIVE(rel->r_info);
1102 r_sym = ELF_R_SYM(r.r_info);
1105 r.r_info = TO_NATIVE(rel->r_info);
1106 r_sym = ELF_R_SYM(r.r_info);
1109 switch (hdr->e_machine) {
1111 if (addend_386_rel(elf, sechdr, &r))
1115 if (addend_arm_rel(elf, sechdr, &r))
1119 if (addend_mips_rel(elf, sechdr, &r))
1123 sym = elf->symtab_start + r_sym;
1124 /* Skip special sections */
1125 if (sym->st_shndx >= SHN_LORESERVE)
1128 tosec = secstrings +
1129 elf->sechdrs[sym->st_shndx].sh_name;
1131 warn_sec_mismatch(modname, fromsec, elf, sym, r);
1136 * A module includes a number of sections that are discarded
1137 * either when loaded or when used as built-in.
1138 * For loaded modules all functions marked __init and all data
1139 * marked __initdata will be discarded when the module has been intialized.
1140 * Likewise for modules used built-in the sections marked __exit
1141 * are discarded because __exit marked function are supposed to be called
1142 * only when a moduel is unloaded which never happes for built-in modules.
1143 * The check_sec_ref() function traverses all relocation records
1144 * to find all references to a section that reference a section that will
1145 * be discarded and warns about it.
1147 static void check_sec_ref(struct module *mod, const char *modname,
1148 struct elf_info *elf,
1149 int section(const char *),
1150 int section_ref_ok(const char *))
1153 Elf_Ehdr *hdr = elf->hdr;
1154 Elf_Shdr *sechdrs = elf->sechdrs;
1156 /* Walk through all sections */
1157 for (i = 0; i < hdr->e_shnum; i++) {
1158 /* We want to process only relocation sections and not .init */
1159 if (sechdrs[i].sh_type == SHT_RELA)
1160 section_rela(modname, elf, &elf->sechdrs[i],
1161 section, section_ref_ok);
1162 else if (sechdrs[i].sh_type == SHT_REL)
1163 section_rel(modname, elf, &elf->sechdrs[i],
1164 section, section_ref_ok);
1169 * Identify sections from which references to either a
1170 * .init or a .exit section is OK.
1172 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1173 * For our future {in}sanity, add a comment that this is the ppc .opd
1174 * section, not the ia64 .opd section.
1175 * ia64 .opd should not point to discarded sections.
1176 * [.rodata] like for .init.text we ignore .rodata references -same reason
1178 static int initexit_section_ref_ok(const char *name)
1181 /* Absolute section names */
1182 const char *namelist1[] = {
1183 "__bug_table", /* used by powerpc for BUG() */
1186 ".cranges", /* used by sh64 */
1188 ".machvec", /* ia64 + powerpc uses these */
1190 ".opd", /* See comment [OPD] */
1192 ".parainstructions",
1194 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1198 ".xt.prop", /* xtensa informational section */
1199 ".xt.lit", /* xtensa informational section */
1202 /* Start of section names */
1203 const char *namelist2[] = {
1206 ".note", /* ignore ELF notes - may contain anything */
1207 ".got", /* powerpc - global offset table */
1208 ".toc", /* powerpc - table of contents */
1211 /* part of section name */
1212 const char *namelist3 [] = {
1213 ".unwind", /* Sample: IA_64.unwind.exit.text */
1217 for (s = namelist1; *s; s++)
1218 if (strcmp(*s, name) == 0)
1220 for (s = namelist2; *s; s++)
1221 if (strncmp(*s, name, strlen(*s)) == 0)
1223 for (s = namelist3; *s; s++)
1224 if (strstr(name, *s) != NULL)
1231 * Identify sections from which references to a .init section is OK.
1233 * Unfortunately references to read only data that referenced .init
1234 * sections had to be excluded. Almost all of these are false
1235 * positives, they are created by gcc. The downside of excluding rodata
1236 * is that there really are some user references from rodata to
1237 * init code, e.g. drivers/video/vgacon.c:
1239 * const struct consw vga_con = {
1240 * con_startup: vgacon_startup,
1242 * where vgacon_startup is __init. If you want to wade through the false
1243 * positives, take out the check for rodata.
1245 static int init_section_ref_ok(const char *name)
1248 /* Absolute section names */
1249 const char *namelist1[] = {
1250 "__dbe_table", /* MIPS generate these */
1251 "__ftr_fixup", /* powerpc cpu feature fixup */
1252 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1254 ".data.rel.ro", /* used by parisc64 */
1259 /* Start of section names */
1260 const char *namelist2[] = {
1267 if (initexit_section_ref_ok(name))
1270 for (s = namelist1; *s; s++)
1271 if (strcmp(*s, name) == 0)
1273 for (s = namelist2; *s; s++)
1274 if (strncmp(*s, name, strlen(*s)) == 0)
1277 /* If section name ends with ".init" we allow references
1278 * as is the case with .initcallN.init, .early_param.init,
1281 if (strrcmp(name, ".init") == 0)
1287 * Identify sections from which references to a .exit section is OK.
1289 static int exit_section_ref_ok(const char *name)
1292 /* Absolute section names */
1293 const char *namelist1[] = {
1301 if (initexit_section_ref_ok(name))
1304 for (s = namelist1; *s; s++)
1305 if (strcmp(*s, name) == 0)
1310 static void read_symbols(char *modname)
1312 const char *symname;
1316 struct elf_info info = { };
1319 if (!parse_elf(&info, modname))
1322 mod = new_module(modname);
1324 /* When there's no vmlinux, don't print warnings about
1325 * unresolved symbols (since there'll be too many ;) */
1326 if (is_vmlinux(modname)) {
1331 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1333 if (license_is_gpl_compatible(license))
1334 mod->gpl_compatible = 1;
1336 mod->gpl_compatible = 0;
1339 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1340 "license", license);
1343 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1344 symname = info.strtab + sym->st_name;
1346 handle_modversions(mod, &info, sym, symname);
1347 handle_moddevtable(mod, &info, sym, symname);
1349 if (!is_vmlinux(modname) ||
1350 (is_vmlinux(modname) && vmlinux_section_warnings)) {
1351 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1352 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1355 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1357 maybe_frob_rcs_version(modname, version, info.modinfo,
1358 version - (char *)info.hdr);
1359 if (version || (all_versions && !is_vmlinux(modname)))
1360 get_src_version(modname, mod->srcversion,
1361 sizeof(mod->srcversion)-1);
1363 parse_elf_finish(&info);
1365 /* Our trick to get versioning for struct_module - it's
1366 * never passed as an argument to an exported function, so
1367 * the automatic versioning doesn't pick it up, but it's really
1368 * important anyhow */
1370 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1375 /* We first write the generated file into memory using the
1376 * following helper, then compare to the file on disk and
1377 * only update the later if anything changed */
1379 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1380 const char *fmt, ...)
1387 len = vsnprintf(tmp, SZ, fmt, ap);
1388 buf_write(buf, tmp, len);
1392 void buf_write(struct buffer *buf, const char *s, int len)
1394 if (buf->size - buf->pos < len) {
1395 buf->size += len + SZ;
1396 buf->p = realloc(buf->p, buf->size);
1398 strncpy(buf->p + buf->pos, s, len);
1402 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1404 const char *e = is_vmlinux(m) ?"":".ko";
1408 fatal("modpost: GPL-incompatible module %s%s "
1409 "uses GPL-only symbol '%s'\n", m, e, s);
1411 case export_unused_gpl:
1412 fatal("modpost: GPL-incompatible module %s%s "
1413 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1415 case export_gpl_future:
1416 warn("modpost: GPL-incompatible module %s%s "
1417 "uses future GPL-only symbol '%s'\n", m, e, s);
1421 case export_unknown:
1427 static void check_for_unused(enum export exp, const char *m, const char *s)
1429 const char *e = is_vmlinux(m) ?"":".ko";
1433 case export_unused_gpl:
1434 warn("modpost: module %s%s "
1435 "uses symbol '%s' marked UNUSED\n", m, e, s);
1443 static void check_exports(struct module *mod)
1445 struct symbol *s, *exp;
1447 for (s = mod->unres; s; s = s->next) {
1448 const char *basename;
1449 exp = find_symbol(s->name);
1450 if (!exp || exp->module == mod)
1452 basename = strrchr(mod->name, '/');
1456 basename = mod->name;
1457 if (!mod->gpl_compatible)
1458 check_for_gpl_usage(exp->export, basename, exp->name);
1459 check_for_unused(exp->export, basename, exp->name);
1464 * Header for the generated file
1466 static void add_header(struct buffer *b, struct module *mod)
1468 buf_printf(b, "#include <linux/module.h>\n");
1469 buf_printf(b, "#include <linux/vermagic.h>\n");
1470 buf_printf(b, "#include <linux/compiler.h>\n");
1471 buf_printf(b, "\n");
1472 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1473 buf_printf(b, "\n");
1474 buf_printf(b, "struct module __this_module\n");
1475 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1476 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1478 buf_printf(b, " .init = init_module,\n");
1479 if (mod->has_cleanup)
1480 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1481 " .exit = cleanup_module,\n"
1483 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1484 buf_printf(b, "};\n");
1488 * Record CRCs for unresolved symbols
1490 static int add_versions(struct buffer *b, struct module *mod)
1492 struct symbol *s, *exp;
1495 for (s = mod->unres; s; s = s->next) {
1496 exp = find_symbol(s->name);
1497 if (!exp || exp->module == mod) {
1498 if (have_vmlinux && !s->weak) {
1499 if (warn_unresolved) {
1500 warn("\"%s\" [%s.ko] undefined!\n",
1501 s->name, mod->name);
1503 merror("\"%s\" [%s.ko] undefined!\n",
1504 s->name, mod->name);
1510 s->module = exp->module;
1511 s->crc_valid = exp->crc_valid;
1518 buf_printf(b, "\n");
1519 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1520 buf_printf(b, "__attribute_used__\n");
1521 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1523 for (s = mod->unres; s; s = s->next) {
1526 if (!s->crc_valid) {
1527 warn("\"%s\" [%s.ko] has no CRC!\n",
1528 s->name, mod->name);
1531 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1534 buf_printf(b, "};\n");
1539 static void add_depends(struct buffer *b, struct module *mod,
1540 struct module *modules)
1546 for (m = modules; m; m = m->next)
1547 m->seen = is_vmlinux(m->name);
1549 buf_printf(b, "\n");
1550 buf_printf(b, "static const char __module_depends[]\n");
1551 buf_printf(b, "__attribute_used__\n");
1552 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1553 buf_printf(b, "\"depends=");
1554 for (s = mod->unres; s; s = s->next) {
1559 if (s->module->seen)
1562 s->module->seen = 1;
1563 p = strrchr(s->module->name, '/');
1567 p = s->module->name;
1568 buf_printf(b, "%s%s", first ? "" : ",", p);
1571 buf_printf(b, "\";\n");
1574 static void add_srcversion(struct buffer *b, struct module *mod)
1576 if (mod->srcversion[0]) {
1577 buf_printf(b, "\n");
1578 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1583 static void write_if_changed(struct buffer *b, const char *fname)
1589 file = fopen(fname, "r");
1593 if (fstat(fileno(file), &st) < 0)
1596 if (st.st_size != b->pos)
1599 tmp = NOFAIL(malloc(b->pos));
1600 if (fread(tmp, 1, b->pos, file) != b->pos)
1603 if (memcmp(tmp, b->p, b->pos) != 0)
1615 file = fopen(fname, "w");
1620 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1627 /* parse Module.symvers file. line format:
1628 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1630 static void read_dump(const char *fname, unsigned int kernel)
1632 unsigned long size, pos = 0;
1633 void *file = grab_file(fname, &size);
1637 /* No symbol versions, silently ignore */
1640 while ((line = get_next_line(&pos, file, size))) {
1641 char *symname, *modname, *d, *export, *end;
1646 if (!(symname = strchr(line, '\t')))
1649 if (!(modname = strchr(symname, '\t')))
1652 if ((export = strchr(modname, '\t')) != NULL)
1654 if (export && ((end = strchr(export, '\t')) != NULL))
1656 crc = strtoul(line, &d, 16);
1657 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1659 mod = find_module(modname);
1661 if (is_vmlinux(modname))
1663 mod = new_module(NOFAIL(strdup(modname)));
1666 s = sym_add_exported(symname, mod, export_no(export));
1669 sym_update_crc(symname, mod, crc, export_no(export));
1673 fatal("parse error in symbol dump file\n");
1676 /* For normal builds always dump all symbols.
1677 * For external modules only dump symbols
1678 * that are not read from kernel Module.symvers.
1680 static int dump_sym(struct symbol *sym)
1682 if (!external_module)
1684 if (sym->vmlinux || sym->kernel)
1689 static void write_dump(const char *fname)
1691 struct buffer buf = { };
1692 struct symbol *symbol;
1695 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1696 symbol = symbolhash[n];
1698 if (dump_sym(symbol))
1699 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1700 symbol->crc, symbol->name,
1701 symbol->module->name,
1702 export_str(symbol->export));
1703 symbol = symbol->next;
1706 write_if_changed(&buf, fname);
1709 int main(int argc, char **argv)
1712 struct buffer buf = { };
1713 char *kernel_read = NULL, *module_read = NULL;
1714 char *dump_write = NULL;
1718 while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) {
1721 kernel_read = optarg;
1724 module_read = optarg;
1725 external_module = 1;
1731 dump_write = optarg;
1737 vmlinux_section_warnings = 0;
1740 warn_unresolved = 1;
1748 read_dump(kernel_read, 1);
1750 read_dump(module_read, 0);
1752 while (optind < argc)
1753 read_symbols(argv[optind++]);
1755 for (mod = modules; mod; mod = mod->next) {
1763 for (mod = modules; mod; mod = mod->next) {
1764 char fname[strlen(mod->name) + 10];
1771 add_header(&buf, mod);
1772 err |= add_versions(&buf, mod);
1773 add_depends(&buf, mod, modules);
1774 add_moddevtable(&buf, mod);
1775 add_srcversion(&buf, mod);
1777 sprintf(fname, "%s.mod.c", mod->name);
1778 write_if_changed(&buf, fname);
1782 write_dump(dump_write);