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);
608 /* if sym is empty or point to a string
609 * like ".[0-9]+" then return 1.
610 * This is the optional prefix added by ld to some sections
612 static int number_prefix(const char *sym)
620 if (c < '0' || c > '9')
626 /* The pattern is an array of simple patterns.
627 * "foo" will match an exact string equal to "foo"
628 * "*foo" will match a string that ends with "foo"
629 * "foo*" will match a string that begins with "foo"
630 * "foo$" will match a string equal to "foo" or "foo.1"
631 * where the '1' can be any number including several digits.
632 * The $ syntax is for sections where ld append a dot number
633 * to make section name unique.
635 int match(const char *sym, const char * const pat[])
640 const char *endp = p + strlen(p) - 1;
644 if (strrcmp(sym, p + 1) == 0)
648 else if (*endp == '*') {
649 if (strncmp(sym, p, strlen(p) - 1) == 0)
653 else if (*endp == '$') {
654 if (strncmp(sym, p, strlen(p) - 1) == 0) {
655 if (number_prefix(sym + strlen(p) - 1))
661 if (strcmp(p, sym) == 0)
669 /* sections that we do not want to do full section mismatch check on */
670 static const char *section_white_list[] =
671 { ".debug*", ".stab*", ".note*", ".got*", ".toc*", NULL };
673 #define ALL_INIT_DATA_SECTIONS \
674 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
675 #define ALL_EXIT_DATA_SECTIONS \
676 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
678 #define ALL_INIT_TEXT_SECTIONS \
679 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
680 #define ALL_EXIT_TEXT_SECTIONS \
681 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
683 #define ALL_INIT_SECTIONS ALL_INIT_DATA_SECTIONS, ALL_INIT_TEXT_SECTIONS
684 #define ALL_EXIT_SECTIONS ALL_EXIT_DATA_SECTIONS, ALL_EXIT_TEXT_SECTIONS
686 #define DATA_SECTIONS ".data$", ".data.rel$"
687 #define TEXT_SECTIONS ".text$"
689 #define INIT_SECTIONS ".init.data$", ".init.text$"
690 #define DEV_INIT_SECTIONS ".devinit.data$", ".devinit.text$"
691 #define CPU_INIT_SECTIONS ".cpuinit.data$", ".cpuinit.text$"
692 #define MEM_INIT_SECTIONS ".meminit.data$", ".meminit.text$"
694 #define EXIT_SECTIONS ".exit.data$", ".exit.text$"
695 #define DEV_EXIT_SECTIONS ".devexit.data$", ".devexit.text$"
696 #define CPU_EXIT_SECTIONS ".cpuexit.data$", ".cpuexit.text$"
697 #define MEM_EXIT_SECTIONS ".memexit.data$", ".memexit.text$"
699 /* init data sections */
700 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
702 /* all init sections */
703 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
705 /* All init and exit sections (code + data) */
706 static const char *init_exit_sections[] =
707 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
710 static const char *data_sections[] = { DATA_SECTIONS, NULL };
712 /* sections that may refer to an init/exit section with no warning */
713 static const char *initref_sections[] =
722 /* symbols in .data that may refer to init/exit sections */
723 static const char *symbol_white_list[] =
726 "*_template", /* scsi uses *_template a lot */
727 "*_timer", /* arm uses ops structures named _timer a lot */
728 "*_sht", /* scsi also used *_sht to some extent */
736 static const char *head_sections[] = { ".head.text*", NULL };
737 static const char *linker_symbols[] =
738 { "__init_begin", "_sinittext", "_einittext", NULL };
740 struct sectioncheck {
741 const char *fromsec[20];
742 const char *tosec[20];
745 const struct sectioncheck sectioncheck[] = {
746 /* Do not reference init/exit code/data from
747 * normal code and data
750 .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
751 .tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }
753 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */
755 .fromsec = { DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, MEM_INIT_SECTIONS, NULL },
756 .tosec = { INIT_SECTIONS, NULL }
758 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
760 .fromsec = { DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, MEM_EXIT_SECTIONS, NULL },
761 .tosec = { EXIT_SECTIONS, NULL }
763 /* Do not use exit code/data from init code */
765 .fromsec = { ALL_INIT_SECTIONS, NULL },
766 .tosec = { ALL_EXIT_SECTIONS, NULL },
768 /* Do not use init code/data from exit code */
770 .fromsec = { ALL_EXIT_SECTIONS, NULL },
771 .tosec = { ALL_INIT_SECTIONS, NULL }
773 /* Do not export init/exit functions or data */
775 .fromsec = { "__ksymtab*", NULL },
776 .tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }
780 static int section_mismatch(const char *fromsec, const char *tosec)
783 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
784 const struct sectioncheck *check = §ioncheck[0];
786 for (i = 0; i < elems; i++) {
787 if (match(fromsec, check->fromsec) &&
788 match(tosec, check->tosec))
797 * Whitelist to allow certain references to pass with no warning.
800 * Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
801 * The pattern is identified by:
802 * fromsec = .text.init.refok* | .data.init.refok*
805 * If a module parameter is declared __initdata and permissions=0
806 * then this is legal despite the warning generated.
807 * We cannot see value of permissions here, so just ignore
809 * The pattern is identified by:
815 * Many drivers utilise a *driver container with references to
816 * add, remove, probe functions etc.
817 * These functions may often be marked __init and we do not want to
819 * the pattern is identified by:
820 * tosec = init or exit section
821 * fromsec = data section
822 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
823 * *probe_one, *_console, *_timer
826 * Whitelist all refereces from .text.head to .init.data
827 * Whitelist all refereces from .text.head to .init.text
830 * Some symbols belong to init section but still it is ok to reference
831 * these from non-init sections as these symbols don't have any memory
832 * allocated for them and symbol address and value are same. So even
833 * if init section is freed, its ok to reference those symbols.
834 * For ex. symbols marking the init section boundaries.
835 * This pattern is identified by
836 * refsymname = __init_begin, _sinittext, _einittext
839 static int secref_whitelist(const char *modname, const char *tosec,
840 const char *fromsec, const char *atsym,
841 const char *refsymname)
843 /* Check for pattern 0 */
844 if (match(fromsec, initref_sections))
847 /* Check for pattern 1 */
848 if (match(tosec, init_data_sections) &&
849 match(fromsec, data_sections) &&
850 (strncmp(atsym, "__param", strlen("__param")) == 0))
853 /* Check for pattern 2 */
854 if (match(tosec, init_exit_sections) &&
855 match(fromsec, data_sections) &&
856 match(atsym, symbol_white_list))
859 /* Check for pattern 3 */
860 if (match(fromsec, head_sections) &&
861 match(tosec, init_sections))
864 /* Check for pattern 4 */
865 if (match(refsymname, linker_symbols))
872 * Find symbol based on relocation record info.
873 * In some cases the symbol supplied is a valid symbol so
874 * return refsym. If st_name != 0 we assume this is a valid symbol.
875 * In other cases the symbol needs to be looked up in the symbol table
876 * based on section and address.
878 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
882 Elf_Sym *near = NULL;
883 Elf64_Sword distance = 20;
886 if (relsym->st_name != 0)
888 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
889 if (sym->st_shndx != relsym->st_shndx)
891 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
893 if (sym->st_value == addr)
895 /* Find a symbol nearby - addr are maybe negative */
896 d = sym->st_value - addr;
898 d = addr - sym->st_value;
904 /* We need a close match */
911 static inline int is_arm_mapping_symbol(const char *str)
913 return str[0] == '$' && strchr("atd", str[1])
914 && (str[2] == '\0' || str[2] == '.');
918 * If there's no name there, ignore it; likewise, ignore it if it's
919 * one of the magic symbols emitted used by current ARM tools.
921 * Otherwise if find_symbols_between() returns those symbols, they'll
922 * fail the whitelist tests and cause lots of false alarms ... fixable
923 * only by merging __exit and __init sections into __text, bloating
924 * the kernel (which is especially evil on embedded platforms).
926 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
928 const char *name = elf->strtab + sym->st_name;
930 if (!name || !strlen(name))
932 return !is_arm_mapping_symbol(name);
936 * Find symbols before or equal addr and after addr - in the section sec.
937 * If we find two symbols with equal offset prefer one with a valid name.
938 * The ELF format may have a better way to detect what type of symbol
939 * it is, but this works for now.
941 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
943 Elf_Sym **before, Elf_Sym **after)
946 Elf_Ehdr *hdr = elf->hdr;
947 Elf_Addr beforediff = ~0;
948 Elf_Addr afterdiff = ~0;
949 const char *secstrings = (void *)hdr +
950 elf->sechdrs[hdr->e_shstrndx].sh_offset;
955 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
958 if (sym->st_shndx >= SHN_LORESERVE)
960 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
961 if (strcmp(symsec, sec) != 0)
963 if (!is_valid_name(elf, sym))
965 if (sym->st_value <= addr) {
966 if ((addr - sym->st_value) < beforediff) {
967 beforediff = addr - sym->st_value;
969 } else if ((addr - sym->st_value) == beforediff) {
973 if ((sym->st_value - addr) < afterdiff) {
974 afterdiff = sym->st_value - addr;
976 } else if ((sym->st_value - addr) == afterdiff)
983 * Print a warning about a section mismatch.
984 * Try to find symbols near it so user can find it.
985 * Check whitelist before warning - it may be a false positive.
987 static void warn_sec_mismatch(const char *modname, const char *fromsec,
988 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
990 const char *refsymname = "";
991 Elf_Sym *before, *after;
993 Elf_Ehdr *hdr = elf->hdr;
994 Elf_Shdr *sechdrs = elf->sechdrs;
995 const char *secstrings = (void *)hdr +
996 sechdrs[hdr->e_shstrndx].sh_offset;
997 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
999 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
1001 refsym = find_elf_symbol(elf, r.r_addend, sym);
1002 if (refsym && strlen(elf->strtab + refsym->st_name))
1003 refsymname = elf->strtab + refsym->st_name;
1005 /* check whitelist - we may ignore it */
1006 if (secref_whitelist(modname, secname, fromsec,
1007 before ? elf->strtab + before->st_name : "",
1011 if (before && after) {
1012 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
1013 "(between '%s' and '%s')\n",
1014 modname, fromsec, (unsigned long long)r.r_offset,
1015 secname, refsymname,
1016 elf->strtab + before->st_name,
1017 elf->strtab + after->st_name);
1018 } else if (before) {
1019 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
1021 modname, fromsec, (unsigned long long)r.r_offset,
1022 secname, refsymname,
1023 elf->strtab + before->st_name);
1025 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
1026 "before '%s' (at offset -0x%llx)\n",
1027 modname, fromsec, (unsigned long long)r.r_offset,
1028 secname, refsymname,
1029 elf->strtab + after->st_name,
1030 (unsigned long long)r.r_offset);
1032 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
1033 modname, fromsec, (unsigned long long)r.r_offset,
1034 secname, refsymname);
1038 static unsigned int *reloc_location(struct elf_info *elf,
1039 Elf_Shdr *sechdr, Elf_Rela *r)
1041 Elf_Shdr *sechdrs = elf->sechdrs;
1042 int section = sechdr->sh_info;
1044 return (void *)elf->hdr + sechdrs[section].sh_offset +
1045 (r->r_offset - sechdrs[section].sh_addr);
1048 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1050 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1051 unsigned int *location = reloc_location(elf, sechdr, r);
1055 r->r_addend = TO_NATIVE(*location);
1058 r->r_addend = TO_NATIVE(*location) + 4;
1059 /* For CONFIG_RELOCATABLE=y */
1060 if (elf->hdr->e_type == ET_EXEC)
1061 r->r_addend += r->r_offset;
1067 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1069 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1073 /* From ARM ABI: (S + A) | T */
1074 r->r_addend = (int)(long)
1075 (elf->symtab_start + ELF_R_SYM(r->r_info));
1078 /* From ARM ABI: ((S + A) | T) - P */
1079 r->r_addend = (int)(long)(elf->hdr +
1081 (r->r_offset - sechdr->sh_addr));
1089 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1091 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1092 unsigned int *location = reloc_location(elf, sechdr, r);
1095 if (r_typ == R_MIPS_HI16)
1096 return 1; /* skip this */
1097 inst = TO_NATIVE(*location);
1100 r->r_addend = inst & 0xffff;
1103 r->r_addend = (inst & 0x03ffffff) << 2;
1112 static void section_rela(const char *modname, struct elf_info *elf,
1119 const char *fromsec;
1122 Elf_Ehdr *hdr = elf->hdr;
1123 Elf_Rela *start = (void *)hdr + sechdr->sh_offset;
1124 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1126 const char *secstrings = (void *)hdr +
1127 elf->sechdrs[hdr->e_shstrndx].sh_offset;
1129 fromsec = secstrings + sechdr->sh_name;
1130 fromsec += strlen(".rela");
1131 /* if from section (name) is know good then skip it */
1132 if (match(fromsec, section_white_list))
1135 for (rela = start; rela < stop; rela++) {
1136 r.r_offset = TO_NATIVE(rela->r_offset);
1137 #if KERNEL_ELFCLASS == ELFCLASS64
1138 if (hdr->e_machine == EM_MIPS) {
1140 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1141 r_sym = TO_NATIVE(r_sym);
1142 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1143 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1145 r.r_info = TO_NATIVE(rela->r_info);
1146 r_sym = ELF_R_SYM(r.r_info);
1149 r.r_info = TO_NATIVE(rela->r_info);
1150 r_sym = ELF_R_SYM(r.r_info);
1152 r.r_addend = TO_NATIVE(rela->r_addend);
1153 sym = elf->symtab_start + r_sym;
1154 /* Skip special sections */
1155 if (sym->st_shndx >= SHN_LORESERVE)
1158 tosec = secstrings +
1159 elf->sechdrs[sym->st_shndx].sh_name;
1160 if (section_mismatch(fromsec, tosec))
1161 warn_sec_mismatch(modname, fromsec, elf, sym, r);
1165 static void section_rel(const char *modname, struct elf_info *elf,
1172 const char *fromsec;
1175 Elf_Ehdr *hdr = elf->hdr;
1176 Elf_Rel *start = (void *)hdr + sechdr->sh_offset;
1177 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1179 const char *secstrings = (void *)hdr +
1180 elf->sechdrs[hdr->e_shstrndx].sh_offset;
1182 fromsec = secstrings + sechdr->sh_name;
1183 fromsec += strlen(".rel");
1184 /* if from section (name) is know good then skip it */
1185 if (match(fromsec, section_white_list))
1188 for (rel = start; rel < stop; rel++) {
1189 r.r_offset = TO_NATIVE(rel->r_offset);
1190 #if KERNEL_ELFCLASS == ELFCLASS64
1191 if (hdr->e_machine == EM_MIPS) {
1193 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1194 r_sym = TO_NATIVE(r_sym);
1195 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1196 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1198 r.r_info = TO_NATIVE(rel->r_info);
1199 r_sym = ELF_R_SYM(r.r_info);
1202 r.r_info = TO_NATIVE(rel->r_info);
1203 r_sym = ELF_R_SYM(r.r_info);
1206 switch (hdr->e_machine) {
1208 if (addend_386_rel(elf, sechdr, &r))
1212 if (addend_arm_rel(elf, sechdr, &r))
1216 if (addend_mips_rel(elf, sechdr, &r))
1220 sym = elf->symtab_start + r_sym;
1221 /* Skip special sections */
1222 if (sym->st_shndx >= SHN_LORESERVE)
1225 tosec = secstrings +
1226 elf->sechdrs[sym->st_shndx].sh_name;
1227 if (section_mismatch(fromsec, tosec))
1228 warn_sec_mismatch(modname, fromsec, elf, sym, r);
1233 * A module includes a number of sections that are discarded
1234 * either when loaded or when used as built-in.
1235 * For loaded modules all functions marked __init and all data
1236 * marked __initdata will be discarded when the module has been intialized.
1237 * Likewise for modules used built-in the sections marked __exit
1238 * are discarded because __exit marked function are supposed to be called
1239 * only when a moduel is unloaded which never happes for built-in modules.
1240 * The check_sec_ref() function traverses all relocation records
1241 * to find all references to a section that reference a section that will
1242 * be discarded and warns about it.
1244 static void check_sec_ref(struct module *mod, const char *modname,
1245 struct elf_info *elf)
1248 Elf_Ehdr *hdr = elf->hdr;
1249 Elf_Shdr *sechdrs = elf->sechdrs;
1251 /* Walk through all sections */
1252 for (i = 0; i < hdr->e_shnum; i++) {
1253 /* We want to process only relocation sections and not .init */
1254 if (sechdrs[i].sh_type == SHT_RELA)
1255 section_rela(modname, elf, &elf->sechdrs[i]);
1256 else if (sechdrs[i].sh_type == SHT_REL)
1257 section_rel(modname, elf, &elf->sechdrs[i]);
1261 static void read_symbols(char *modname)
1263 const char *symname;
1267 struct elf_info info = { };
1270 if (!parse_elf(&info, modname))
1273 mod = new_module(modname);
1275 /* When there's no vmlinux, don't print warnings about
1276 * unresolved symbols (since there'll be too many ;) */
1277 if (is_vmlinux(modname)) {
1282 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1284 if (license_is_gpl_compatible(license))
1285 mod->gpl_compatible = 1;
1287 mod->gpl_compatible = 0;
1290 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1291 "license", license);
1294 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1295 symname = info.strtab + sym->st_name;
1297 handle_modversions(mod, &info, sym, symname);
1298 handle_moddevtable(mod, &info, sym, symname);
1300 if (!is_vmlinux(modname) ||
1301 (is_vmlinux(modname) && vmlinux_section_warnings))
1302 check_sec_ref(mod, modname, &info);
1304 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1306 maybe_frob_rcs_version(modname, version, info.modinfo,
1307 version - (char *)info.hdr);
1308 if (version || (all_versions && !is_vmlinux(modname)))
1309 get_src_version(modname, mod->srcversion,
1310 sizeof(mod->srcversion)-1);
1312 parse_elf_finish(&info);
1314 /* Our trick to get versioning for struct_module - it's
1315 * never passed as an argument to an exported function, so
1316 * the automatic versioning doesn't pick it up, but it's really
1317 * important anyhow */
1319 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1324 /* We first write the generated file into memory using the
1325 * following helper, then compare to the file on disk and
1326 * only update the later if anything changed */
1328 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1329 const char *fmt, ...)
1336 len = vsnprintf(tmp, SZ, fmt, ap);
1337 buf_write(buf, tmp, len);
1341 void buf_write(struct buffer *buf, const char *s, int len)
1343 if (buf->size - buf->pos < len) {
1344 buf->size += len + SZ;
1345 buf->p = realloc(buf->p, buf->size);
1347 strncpy(buf->p + buf->pos, s, len);
1351 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1353 const char *e = is_vmlinux(m) ?"":".ko";
1357 fatal("modpost: GPL-incompatible module %s%s "
1358 "uses GPL-only symbol '%s'\n", m, e, s);
1360 case export_unused_gpl:
1361 fatal("modpost: GPL-incompatible module %s%s "
1362 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1364 case export_gpl_future:
1365 warn("modpost: GPL-incompatible module %s%s "
1366 "uses future GPL-only symbol '%s'\n", m, e, s);
1370 case export_unknown:
1376 static void check_for_unused(enum export exp, const char *m, const char *s)
1378 const char *e = is_vmlinux(m) ?"":".ko";
1382 case export_unused_gpl:
1383 warn("modpost: module %s%s "
1384 "uses symbol '%s' marked UNUSED\n", m, e, s);
1392 static void check_exports(struct module *mod)
1394 struct symbol *s, *exp;
1396 for (s = mod->unres; s; s = s->next) {
1397 const char *basename;
1398 exp = find_symbol(s->name);
1399 if (!exp || exp->module == mod)
1401 basename = strrchr(mod->name, '/');
1405 basename = mod->name;
1406 if (!mod->gpl_compatible)
1407 check_for_gpl_usage(exp->export, basename, exp->name);
1408 check_for_unused(exp->export, basename, exp->name);
1413 * Header for the generated file
1415 static void add_header(struct buffer *b, struct module *mod)
1417 buf_printf(b, "#include <linux/module.h>\n");
1418 buf_printf(b, "#include <linux/vermagic.h>\n");
1419 buf_printf(b, "#include <linux/compiler.h>\n");
1420 buf_printf(b, "\n");
1421 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1422 buf_printf(b, "\n");
1423 buf_printf(b, "struct module __this_module\n");
1424 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1425 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1427 buf_printf(b, " .init = init_module,\n");
1428 if (mod->has_cleanup)
1429 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1430 " .exit = cleanup_module,\n"
1432 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1433 buf_printf(b, "};\n");
1437 * Record CRCs for unresolved symbols
1439 static int add_versions(struct buffer *b, struct module *mod)
1441 struct symbol *s, *exp;
1444 for (s = mod->unres; s; s = s->next) {
1445 exp = find_symbol(s->name);
1446 if (!exp || exp->module == mod) {
1447 if (have_vmlinux && !s->weak) {
1448 if (warn_unresolved) {
1449 warn("\"%s\" [%s.ko] undefined!\n",
1450 s->name, mod->name);
1452 merror("\"%s\" [%s.ko] undefined!\n",
1453 s->name, mod->name);
1459 s->module = exp->module;
1460 s->crc_valid = exp->crc_valid;
1467 buf_printf(b, "\n");
1468 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1469 buf_printf(b, "__attribute_used__\n");
1470 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1472 for (s = mod->unres; s; s = s->next) {
1475 if (!s->crc_valid) {
1476 warn("\"%s\" [%s.ko] has no CRC!\n",
1477 s->name, mod->name);
1480 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1483 buf_printf(b, "};\n");
1488 static void add_depends(struct buffer *b, struct module *mod,
1489 struct module *modules)
1495 for (m = modules; m; m = m->next)
1496 m->seen = is_vmlinux(m->name);
1498 buf_printf(b, "\n");
1499 buf_printf(b, "static const char __module_depends[]\n");
1500 buf_printf(b, "__attribute_used__\n");
1501 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1502 buf_printf(b, "\"depends=");
1503 for (s = mod->unres; s; s = s->next) {
1508 if (s->module->seen)
1511 s->module->seen = 1;
1512 p = strrchr(s->module->name, '/');
1516 p = s->module->name;
1517 buf_printf(b, "%s%s", first ? "" : ",", p);
1520 buf_printf(b, "\";\n");
1523 static void add_srcversion(struct buffer *b, struct module *mod)
1525 if (mod->srcversion[0]) {
1526 buf_printf(b, "\n");
1527 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1532 static void write_if_changed(struct buffer *b, const char *fname)
1538 file = fopen(fname, "r");
1542 if (fstat(fileno(file), &st) < 0)
1545 if (st.st_size != b->pos)
1548 tmp = NOFAIL(malloc(b->pos));
1549 if (fread(tmp, 1, b->pos, file) != b->pos)
1552 if (memcmp(tmp, b->p, b->pos) != 0)
1564 file = fopen(fname, "w");
1569 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1576 /* parse Module.symvers file. line format:
1577 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1579 static void read_dump(const char *fname, unsigned int kernel)
1581 unsigned long size, pos = 0;
1582 void *file = grab_file(fname, &size);
1586 /* No symbol versions, silently ignore */
1589 while ((line = get_next_line(&pos, file, size))) {
1590 char *symname, *modname, *d, *export, *end;
1595 if (!(symname = strchr(line, '\t')))
1598 if (!(modname = strchr(symname, '\t')))
1601 if ((export = strchr(modname, '\t')) != NULL)
1603 if (export && ((end = strchr(export, '\t')) != NULL))
1605 crc = strtoul(line, &d, 16);
1606 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1608 mod = find_module(modname);
1610 if (is_vmlinux(modname))
1612 mod = new_module(NOFAIL(strdup(modname)));
1615 s = sym_add_exported(symname, mod, export_no(export));
1618 sym_update_crc(symname, mod, crc, export_no(export));
1622 fatal("parse error in symbol dump file\n");
1625 /* For normal builds always dump all symbols.
1626 * For external modules only dump symbols
1627 * that are not read from kernel Module.symvers.
1629 static int dump_sym(struct symbol *sym)
1631 if (!external_module)
1633 if (sym->vmlinux || sym->kernel)
1638 static void write_dump(const char *fname)
1640 struct buffer buf = { };
1641 struct symbol *symbol;
1644 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1645 symbol = symbolhash[n];
1647 if (dump_sym(symbol))
1648 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1649 symbol->crc, symbol->name,
1650 symbol->module->name,
1651 export_str(symbol->export));
1652 symbol = symbol->next;
1655 write_if_changed(&buf, fname);
1658 int main(int argc, char **argv)
1661 struct buffer buf = { };
1662 char *kernel_read = NULL, *module_read = NULL;
1663 char *dump_write = NULL;
1667 while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) {
1670 kernel_read = optarg;
1673 module_read = optarg;
1674 external_module = 1;
1680 dump_write = optarg;
1686 vmlinux_section_warnings = 0;
1689 warn_unresolved = 1;
1697 read_dump(kernel_read, 1);
1699 read_dump(module_read, 0);
1701 while (optind < argc)
1702 read_symbols(argv[optind++]);
1704 for (mod = modules; mod; mod = mod->next) {
1712 for (mod = modules; mod; mod = mod->next) {
1713 char fname[strlen(mod->name) + 10];
1720 add_header(&buf, mod);
1721 err |= add_versions(&buf, mod);
1722 add_depends(&buf, mod, modules);
1723 add_moddevtable(&buf, mod);
1724 add_srcversion(&buf, mod);
1726 sprintf(fname, "%s.mod.c", mod->name);
1727 write_if_changed(&buf, fname);
1731 write_dump(dump_write);