1 /* Postprocess module symbol versions
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006 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 /* Only warn about unresolved symbols */
27 static int warn_unresolved = 0;
28 /* How a symbol is exported */
30 export_plain, export_unused, export_gpl,
31 export_unused_gpl, export_gpl_future, export_unknown
34 void fatal(const char *fmt, ...)
38 fprintf(stderr, "FATAL: ");
40 va_start(arglist, fmt);
41 vfprintf(stderr, fmt, arglist);
47 void warn(const char *fmt, ...)
51 fprintf(stderr, "WARNING: ");
53 va_start(arglist, fmt);
54 vfprintf(stderr, fmt, arglist);
58 void merror(const char *fmt, ...)
62 fprintf(stderr, "ERROR: ");
64 va_start(arglist, fmt);
65 vfprintf(stderr, fmt, arglist);
69 static int is_vmlinux(const char *modname)
73 if ((myname = strrchr(modname, '/')))
78 return strcmp(myname, "vmlinux") == 0;
81 void *do_nofail(void *ptr, const char *expr)
84 fatal("modpost: Memory allocation failure: %s.\n", expr);
89 /* A list of all modules we processed */
91 static struct module *modules;
93 static struct module *find_module(char *modname)
97 for (mod = modules; mod; mod = mod->next)
98 if (strcmp(mod->name, modname) == 0)
103 static struct module *new_module(char *modname)
108 mod = NOFAIL(malloc(sizeof(*mod)));
109 memset(mod, 0, sizeof(*mod));
110 p = NOFAIL(strdup(modname));
112 /* strip trailing .o */
113 if ((s = strrchr(p, '.')) != NULL)
114 if (strcmp(s, ".o") == 0)
119 mod->gpl_compatible = -1;
126 /* A hash of all exported symbols,
127 * struct symbol is also used for lists of unresolved symbols */
129 #define SYMBOL_HASH_SIZE 1024
133 struct module *module;
137 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
138 unsigned int kernel:1; /* 1 if symbol is from kernel
139 * (only for external modules) **/
140 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
141 enum export export; /* Type of export */
145 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
147 /* This is based on the hash agorithm from gdbm, via tdb */
148 static inline unsigned int tdb_hash(const char *name)
150 unsigned value; /* Used to compute the hash value. */
151 unsigned i; /* Used to cycle through random values. */
153 /* Set the initial value from the key size. */
154 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
155 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
157 return (1103515243 * value + 12345);
161 * Allocate a new symbols for use in the hash of exported symbols or
162 * the list of unresolved symbols per module
164 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
167 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
169 memset(s, 0, sizeof(*s));
170 strcpy(s->name, name);
176 /* For the hash of exported symbols */
177 static struct symbol *new_symbol(const char *name, struct module *module,
183 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
184 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
185 new->module = module;
186 new->export = export;
190 static struct symbol *find_symbol(const char *name)
194 /* For our purposes, .foo matches foo. PPC64 needs this. */
198 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
199 if (strcmp(s->name, name) == 0)
209 { .str = "EXPORT_SYMBOL", .export = export_plain },
210 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
211 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
212 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
213 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
214 { .str = "(unknown)", .export = export_unknown },
218 static const char *export_str(enum export ex)
220 return export_list[ex].str;
223 static enum export export_no(const char * s)
227 return export_unknown;
228 for (i = 0; export_list[i].export != export_unknown; i++) {
229 if (strcmp(export_list[i].str, s) == 0)
230 return export_list[i].export;
232 return export_unknown;
235 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
237 if (sec == elf->export_sec)
239 else if (sec == elf->export_unused_sec)
240 return export_unused;
241 else if (sec == elf->export_gpl_sec)
243 else if (sec == elf->export_unused_gpl_sec)
244 return export_unused_gpl;
245 else if (sec == elf->export_gpl_future_sec)
246 return export_gpl_future;
248 return export_unknown;
252 * Add an exported symbol - it may have already been added without a
253 * CRC, in this case just update the CRC
255 static struct symbol *sym_add_exported(const char *name, struct module *mod,
258 struct symbol *s = find_symbol(name);
261 s = new_symbol(name, mod, export);
264 warn("%s: '%s' exported twice. Previous export "
265 "was in %s%s\n", mod->name, name,
267 is_vmlinux(s->module->name) ?"":".ko");
271 s->vmlinux = is_vmlinux(mod->name);
277 static void sym_update_crc(const char *name, struct module *mod,
278 unsigned int crc, enum export export)
280 struct symbol *s = find_symbol(name);
283 s = new_symbol(name, mod, export);
288 void *grab_file(const char *filename, unsigned long *size)
294 fd = open(filename, O_RDONLY);
295 if (fd < 0 || fstat(fd, &st) != 0)
299 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
302 if (map == MAP_FAILED)
308 * Return a copy of the next line in a mmap'ed file.
309 * spaces in the beginning of the line is trimmed away.
310 * Return a pointer to a static buffer.
312 char* get_next_line(unsigned long *pos, void *file, unsigned long size)
314 static char line[4096];
317 signed char *p = (signed char *)file + *pos;
320 for (; *pos < size ; (*pos)++)
322 if (skip && isspace(*p)) {
327 if (*p != '\n' && (*pos < size)) {
331 break; /* Too long, stop */
342 void release_file(void *file, unsigned long size)
347 static int parse_elf(struct elf_info *info, const char *filename)
354 hdr = grab_file(filename, &info->size);
360 if (info->size < sizeof(*hdr)) {
361 /* file too small, assume this is an empty .o file */
364 /* Is this a valid ELF file? */
365 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
366 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
367 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
368 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
369 /* Not an ELF file - silently ignore it */
372 /* Fix endianness in ELF header */
373 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
374 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
375 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
376 hdr->e_machine = TO_NATIVE(hdr->e_machine);
377 sechdrs = (void *)hdr + hdr->e_shoff;
378 info->sechdrs = sechdrs;
380 /* Fix endianness in section headers */
381 for (i = 0; i < hdr->e_shnum; i++) {
382 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
383 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
384 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
385 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
386 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
387 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
389 /* Find symbol table. */
390 for (i = 1; i < hdr->e_shnum; i++) {
391 const char *secstrings
392 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
395 if (sechdrs[i].sh_offset > info->size) {
396 fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
399 secname = secstrings + sechdrs[i].sh_name;
400 if (strcmp(secname, ".modinfo") == 0) {
401 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
402 info->modinfo_len = sechdrs[i].sh_size;
403 } else if (strcmp(secname, "__ksymtab") == 0)
404 info->export_sec = i;
405 else if (strcmp(secname, "__ksymtab_unused") == 0)
406 info->export_unused_sec = i;
407 else if (strcmp(secname, "__ksymtab_gpl") == 0)
408 info->export_gpl_sec = i;
409 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
410 info->export_unused_gpl_sec = i;
411 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
412 info->export_gpl_future_sec = i;
414 if (sechdrs[i].sh_type != SHT_SYMTAB)
417 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
418 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
419 + sechdrs[i].sh_size;
420 info->strtab = (void *)hdr +
421 sechdrs[sechdrs[i].sh_link].sh_offset;
423 if (!info->symtab_start) {
424 fatal("%s has no symtab?\n", filename);
426 /* Fix endianness in symbols */
427 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
428 sym->st_shndx = TO_NATIVE(sym->st_shndx);
429 sym->st_name = TO_NATIVE(sym->st_name);
430 sym->st_value = TO_NATIVE(sym->st_value);
431 sym->st_size = TO_NATIVE(sym->st_size);
436 static void parse_elf_finish(struct elf_info *info)
438 release_file(info->hdr, info->size);
441 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
442 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
444 static void handle_modversions(struct module *mod, struct elf_info *info,
445 Elf_Sym *sym, const char *symname)
448 enum export export = export_from_sec(info, sym->st_shndx);
450 switch (sym->st_shndx) {
452 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
456 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
457 crc = (unsigned int) sym->st_value;
458 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
463 /* undefined symbol */
464 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
465 ELF_ST_BIND(sym->st_info) != STB_WEAK)
467 /* ignore global offset table */
468 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
470 /* ignore __this_module, it will be resolved shortly */
471 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
473 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
474 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
475 /* add compatibility with older glibc */
476 #ifndef STT_SPARC_REGISTER
477 #define STT_SPARC_REGISTER STT_REGISTER
479 if (info->hdr->e_machine == EM_SPARC ||
480 info->hdr->e_machine == EM_SPARCV9) {
481 /* Ignore register directives. */
482 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
484 if (symname[0] == '.') {
485 char *munged = strdup(symname);
487 munged[1] = toupper(munged[1]);
493 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
494 strlen(MODULE_SYMBOL_PREFIX)) == 0)
495 mod->unres = alloc_symbol(symname +
496 strlen(MODULE_SYMBOL_PREFIX),
497 ELF_ST_BIND(sym->st_info) == STB_WEAK,
501 /* All exported symbols */
502 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
503 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
506 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
508 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
509 mod->has_cleanup = 1;
515 * Parse tag=value strings from .modinfo section
517 static char *next_string(char *string, unsigned long *secsize)
519 /* Skip non-zero chars */
522 if ((*secsize)-- <= 1)
526 /* Skip any zero padding. */
529 if ((*secsize)-- <= 1)
535 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
536 const char *tag, char *info)
539 unsigned int taglen = strlen(tag);
540 unsigned long size = modinfo_len;
543 size -= info - (char *)modinfo;
544 modinfo = next_string(info, &size);
547 for (p = modinfo; p; p = next_string(p, &size)) {
548 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
549 return p + taglen + 1;
554 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
558 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
562 * Test if string s ends in string sub
565 static int strrcmp(const char *s, const char *sub)
573 sublen = strlen(sub);
575 if ((slen == 0) || (sublen == 0))
581 return memcmp(s + slen - sublen, sub, sublen);
585 * Whitelist to allow certain references to pass with no warning.
588 * Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
589 * The pattern is identified by:
590 * fromsec = .text.init.refok | .data.init.refok
593 * If a module parameter is declared __initdata and permissions=0
594 * then this is legal despite the warning generated.
595 * We cannot see value of permissions here, so just ignore
597 * The pattern is identified by:
603 * Many drivers utilise a *driver container with references to
604 * add, remove, probe functions etc.
605 * These functions may often be marked __init and we do not want to
607 * the pattern is identified by:
608 * tosec = .init.text | .exit.text | .init.data
610 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
613 * Whitelist all references from .pci_fixup* section to .init.text
614 * This is part of the PCI init when built-in
617 * Whitelist all refereces from .text.head to .init.data
618 * Whitelist all refereces from .text.head to .init.text
621 * Some symbols belong to init section but still it is ok to reference
622 * these from non-init sections as these symbols don't have any memory
623 * allocated for them and symbol address and value are same. So even
624 * if init section is freed, its ok to reference those symbols.
625 * For ex. symbols marking the init section boundaries.
626 * This pattern is identified by
627 * refsymname = __init_begin, _sinittext, _einittext
630 * During the early init phase we have references from .init.text to
631 * .text we have an intended section mismatch - do not warn about it.
632 * See kernel_init() in init/main.c
635 * atsym = kernel_init
638 * Logos used in drivers/video/logo reside in __initdata but the
639 * funtion that references them are EXPORT_SYMBOL() so cannot be
640 * marker __init. So we whitelist them here.
647 * Symbols contained in .paravirtprobe may safely reference .init.text.
650 * fromsec = .paravirtprobe
653 * Some of functions are common code between boot time and hotplug
654 * time. The bootmem allocater is called only boot time in its
655 * functions. So it's ok to reference.
659 * ia64 has machvec table for each platform and
660 * powerpc has a machine desc table for each platform.
661 * It is mixture of function pointers of .init.text and .text.
662 * fromsec = .machvec | .machine.desc
664 static int secref_whitelist(const char *modname, const char *tosec,
665 const char *fromsec, const char *atsym,
666 const char *refsymname)
670 const char *pat2sym[] = {
672 "_template", /* scsi uses *_template a lot */
673 "_sht", /* scsi also used *_sht to some extent */
682 const char *pat3refsym[] = {
689 const char *pat4sym[] = {
690 "sparse_index_alloc",
691 "zone_wait_table_init",
695 /* Check for pattern 0 */
696 if ((strcmp(fromsec, ".text.init.refok") == 0) ||
697 (strcmp(fromsec, ".data.init.refok") == 0))
700 /* Check for pattern 1 */
701 if (strcmp(tosec, ".init.data") != 0)
703 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
705 if (strncmp(atsym, "__param", strlen("__param")) != 0)
711 /* Check for pattern 2 */
712 if ((strcmp(tosec, ".init.text") != 0) &&
713 (strcmp(tosec, ".exit.text") != 0) &&
714 (strcmp(tosec, ".init.data") != 0))
716 if (strcmp(fromsec, ".data") != 0)
719 for (s = pat2sym; *s; s++)
720 if (strrcmp(atsym, *s) == 0)
725 /* Check for pattern 3 */
726 if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
727 (strcmp(tosec, ".init.text") == 0))
730 /* Check for pattern 4 */
731 if ((strcmp(fromsec, ".text.head") == 0) &&
732 ((strcmp(tosec, ".init.data") == 0) ||
733 (strcmp(tosec, ".init.text") == 0)))
736 /* Check for pattern 5 */
737 for (s = pat3refsym; *s; s++)
738 if (strcmp(refsymname, *s) == 0)
741 /* Check for pattern 6 */
742 if ((strcmp(tosec, ".init.text") == 0) &&
743 (strcmp(fromsec, ".text") == 0) &&
744 (strcmp(refsymname, "kernel_init") == 0))
747 /* Check for pattern 7 */
748 if ((strcmp(tosec, ".init.data") == 0) &&
749 (strncmp(fromsec, ".text", strlen(".text")) == 0) &&
750 (strncmp(refsymname, "logo_", strlen("logo_")) == 0))
753 /* Check for pattern 8 */
754 if ((strcmp(tosec, ".init.text") == 0) &&
755 (strcmp(fromsec, ".paravirtprobe") == 0))
758 /* Check for pattern 9 */
759 if ((strcmp(tosec, ".init.text") == 0) &&
760 (strcmp(fromsec, ".text") == 0))
761 for (s = pat4sym; *s; s++)
762 if (strcmp(atsym, *s) == 0)
765 /* Check for pattern 10 */
766 if ((strcmp(fromsec, ".machvec") == 0) ||
767 (strcmp(fromsec, ".machine.desc") == 0))
774 * Find symbol based on relocation record info.
775 * In some cases the symbol supplied is a valid symbol so
776 * return refsym. If st_name != 0 we assume this is a valid symbol.
777 * In other cases the symbol needs to be looked up in the symbol table
778 * based on section and address.
780 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
785 if (relsym->st_name != 0)
787 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
788 if (sym->st_shndx != relsym->st_shndx)
790 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
792 if (sym->st_value == addr)
798 static inline int is_arm_mapping_symbol(const char *str)
800 return str[0] == '$' && strchr("atd", str[1])
801 && (str[2] == '\0' || str[2] == '.');
805 * If there's no name there, ignore it; likewise, ignore it if it's
806 * one of the magic symbols emitted used by current ARM tools.
808 * Otherwise if find_symbols_between() returns those symbols, they'll
809 * fail the whitelist tests and cause lots of false alarms ... fixable
810 * only by merging __exit and __init sections into __text, bloating
811 * the kernel (which is especially evil on embedded platforms).
813 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
815 const char *name = elf->strtab + sym->st_name;
817 if (!name || !strlen(name))
819 return !is_arm_mapping_symbol(name);
823 * Find symbols before or equal addr and after addr - in the section sec.
824 * If we find two symbols with equal offset prefer one with a valid name.
825 * The ELF format may have a better way to detect what type of symbol
826 * it is, but this works for now.
828 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
830 Elf_Sym **before, Elf_Sym **after)
833 Elf_Ehdr *hdr = elf->hdr;
834 Elf_Addr beforediff = ~0;
835 Elf_Addr afterdiff = ~0;
836 const char *secstrings = (void *)hdr +
837 elf->sechdrs[hdr->e_shstrndx].sh_offset;
842 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
845 if (sym->st_shndx >= SHN_LORESERVE)
847 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
848 if (strcmp(symsec, sec) != 0)
850 if (!is_valid_name(elf, sym))
852 if (sym->st_value <= addr) {
853 if ((addr - sym->st_value) < beforediff) {
854 beforediff = addr - sym->st_value;
857 else if ((addr - sym->st_value) == beforediff) {
863 if ((sym->st_value - addr) < afterdiff) {
864 afterdiff = sym->st_value - addr;
867 else if ((sym->st_value - addr) == afterdiff) {
875 * Print a warning about a section mismatch.
876 * Try to find symbols near it so user can find it.
877 * Check whitelist before warning - it may be a false positive.
879 static void warn_sec_mismatch(const char *modname, const char *fromsec,
880 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
882 const char *refsymname = "";
883 Elf_Sym *before, *after;
885 Elf_Ehdr *hdr = elf->hdr;
886 Elf_Shdr *sechdrs = elf->sechdrs;
887 const char *secstrings = (void *)hdr +
888 sechdrs[hdr->e_shstrndx].sh_offset;
889 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
891 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
893 refsym = find_elf_symbol(elf, r.r_addend, sym);
894 if (refsym && strlen(elf->strtab + refsym->st_name))
895 refsymname = elf->strtab + refsym->st_name;
897 /* check whitelist - we may ignore it */
899 secref_whitelist(modname, secname, fromsec,
900 elf->strtab + before->st_name, refsymname))
903 /* fromsec whitelist - without a valid 'before'
904 * powerpc has a GOT table in .got2 section */
905 if (strcmp(fromsec, ".got2") == 0)
908 if (before && after) {
909 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
910 "(between '%s' and '%s')\n",
911 modname, fromsec, (unsigned long long)r.r_offset,
913 elf->strtab + before->st_name,
914 elf->strtab + after->st_name);
916 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
918 modname, fromsec, (unsigned long long)r.r_offset,
920 elf->strtab + before->st_name);
922 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
923 "before '%s' (at offset -0x%llx)\n",
924 modname, fromsec, (unsigned long long)r.r_offset,
926 elf->strtab + after->st_name);
928 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
929 modname, fromsec, (unsigned long long)r.r_offset,
930 secname, refsymname);
934 static void addend_386_rel(struct elf_info *elf, int section, Elf_Rela *r)
936 Elf_Shdr *sechdrs = elf->sechdrs;
938 unsigned int *location;
940 r_typ = ELF_R_TYPE(r->r_info);
941 location = (void *)elf->hdr +
942 sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;
945 r->r_addend = TO_NATIVE(*location);
948 r->r_addend = TO_NATIVE(*location) + 4;
953 static void addend_arm_rel(struct elf_info *elf, int section, Elf_Rela *r)
955 Elf_Shdr *sechdrs = elf->sechdrs;
957 unsigned int *location;
959 r_typ = ELF_R_TYPE(r->r_info);
960 location = (void *)elf->hdr +
961 sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;
964 r->r_addend = TO_NATIVE(*location);
967 r->r_addend = ((TO_NATIVE(*location) & 0x00ffffff) << 2) + 8;
972 static int addend_mips_rel(struct elf_info *elf, int section, Elf_Rela *r)
974 Elf_Shdr *sechdrs = elf->sechdrs;
976 unsigned int *location;
979 r_typ = ELF_R_TYPE(r->r_info);
980 if (r_typ == R_MIPS_HI16)
981 return 1; /* skip this */
982 location = (void *)elf->hdr +
983 sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;
984 inst = TO_NATIVE(*location);
987 r->r_addend = ((inst & 0xffff) ^ 0x8000) - 0x8000;
990 r->r_addend = (inst & 0x03ffffff) << 2;
997 * A module includes a number of sections that are discarded
998 * either when loaded or when used as built-in.
999 * For loaded modules all functions marked __init and all data
1000 * marked __initdata will be discarded when the module has been intialized.
1001 * Likewise for modules used built-in the sections marked __exit
1002 * are discarded because __exit marked function are supposed to be called
1003 * only when a moduel is unloaded which never happes for built-in modules.
1004 * The check_sec_ref() function traverses all relocation records
1005 * to find all references to a section that reference a section that will
1006 * be discarded and warns about it.
1008 static void check_sec_ref(struct module *mod, const char *modname,
1009 struct elf_info *elf,
1010 int section(const char*),
1011 int section_ref_ok(const char *))
1015 Elf_Ehdr *hdr = elf->hdr;
1016 Elf_Shdr *sechdrs = elf->sechdrs;
1017 const char *secstrings = (void *)hdr +
1018 sechdrs[hdr->e_shstrndx].sh_offset;
1020 /* Walk through all sections */
1021 for (i = 0; i < hdr->e_shnum; i++) {
1022 const char *name = secstrings + sechdrs[i].sh_name;
1023 const char *secname;
1026 /* We want to process only relocation sections and not .init */
1027 if (sechdrs[i].sh_type == SHT_RELA) {
1029 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
1030 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
1031 name += strlen(".rela");
1032 if (section_ref_ok(name))
1035 for (rela = start; rela < stop; rela++) {
1036 r.r_offset = TO_NATIVE(rela->r_offset);
1037 #if KERNEL_ELFCLASS == ELFCLASS64
1038 if (hdr->e_machine == EM_MIPS) {
1040 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1041 r_sym = TO_NATIVE(r_sym);
1042 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1043 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1045 r.r_info = TO_NATIVE(rela->r_info);
1046 r_sym = ELF_R_SYM(r.r_info);
1049 r.r_info = TO_NATIVE(rela->r_info);
1050 r_sym = ELF_R_SYM(r.r_info);
1052 r.r_addend = TO_NATIVE(rela->r_addend);
1053 sym = elf->symtab_start + r_sym;
1054 /* Skip special sections */
1055 if (sym->st_shndx >= SHN_LORESERVE)
1058 secname = secstrings +
1059 sechdrs[sym->st_shndx].sh_name;
1060 if (section(secname))
1061 warn_sec_mismatch(modname, name,
1064 } else if (sechdrs[i].sh_type == SHT_REL) {
1066 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
1067 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
1068 name += strlen(".rel");
1069 if (section_ref_ok(name))
1072 for (rel = start; rel < stop; rel++) {
1073 r.r_offset = TO_NATIVE(rel->r_offset);
1074 #if KERNEL_ELFCLASS == ELFCLASS64
1075 if (hdr->e_machine == EM_MIPS) {
1077 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1078 r_sym = TO_NATIVE(r_sym);
1079 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1080 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1082 r.r_info = TO_NATIVE(rel->r_info);
1083 r_sym = ELF_R_SYM(r.r_info);
1086 r.r_info = TO_NATIVE(rel->r_info);
1087 r_sym = ELF_R_SYM(r.r_info);
1090 if (hdr->e_machine == EM_386)
1091 addend_386_rel(elf, i, &r);
1092 else if (hdr->e_machine == EM_ARM)
1093 addend_arm_rel(elf, i, &r);
1094 else if (hdr->e_machine == EM_MIPS) {
1095 if (addend_mips_rel(elf, i, &r))
1098 sym = elf->symtab_start + r_sym;
1099 /* Skip special sections */
1100 if (sym->st_shndx >= SHN_LORESERVE)
1103 secname = secstrings +
1104 sechdrs[sym->st_shndx].sh_name;
1105 if (section(secname))
1106 warn_sec_mismatch(modname, name,
1114 * Functions used only during module init is marked __init and is stored in
1115 * a .init.text section. Likewise data is marked __initdata and stored in
1116 * a .init.data section.
1117 * If this section is one of these sections return 1
1118 * See include/linux/init.h for the details
1120 static int init_section(const char *name)
1122 if (strcmp(name, ".init") == 0)
1124 if (strncmp(name, ".init.", strlen(".init.")) == 0)
1130 * Identify sections from which references to a .init section is OK.
1132 * Unfortunately references to read only data that referenced .init
1133 * sections had to be excluded. Almost all of these are false
1134 * positives, they are created by gcc. The downside of excluding rodata
1135 * is that there really are some user references from rodata to
1136 * init code, e.g. drivers/video/vgacon.c:
1138 * const struct consw vga_con = {
1139 * con_startup: vgacon_startup,
1141 * where vgacon_startup is __init. If you want to wade through the false
1142 * positives, take out the check for rodata.
1144 static int init_section_ref_ok(const char *name)
1147 /* Absolute section names */
1148 const char *namelist1[] = {
1150 ".opd", /* see comment [OPD] at exit_section_ref_ok() */
1151 ".toc1", /* used by ppc64 */
1153 ".data.rel.ro", /* used by parisc64 */
1154 ".parainstructions",
1156 "__bug_table", /* used by powerpc for BUG() */
1157 ".pci_fixup_header",
1164 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1165 "__ftr_fixup", /* powerpc cpu feature fixup */
1166 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1169 /* Start of section names */
1170 const char *namelist2[] = {
1175 ".parainstructions",
1179 /* part of section name */
1180 const char *namelist3 [] = {
1181 ".unwind", /* sample: IA_64.unwind.init.text */
1185 for (s = namelist1; *s; s++)
1186 if (strcmp(*s, name) == 0)
1188 for (s = namelist2; *s; s++)
1189 if (strncmp(*s, name, strlen(*s)) == 0)
1191 for (s = namelist3; *s; s++)
1192 if (strstr(name, *s) != NULL)
1194 if (strrcmp(name, ".init") == 0)
1200 * Functions used only during module exit is marked __exit and is stored in
1201 * a .exit.text section. Likewise data is marked __exitdata and stored in
1202 * a .exit.data section.
1203 * If this section is one of these sections return 1
1204 * See include/linux/init.h for the details
1206 static int exit_section(const char *name)
1208 if (strcmp(name, ".exit.text") == 0)
1210 if (strcmp(name, ".exit.data") == 0)
1217 * Identify sections from which references to a .exit section is OK.
1219 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1220 * For our future {in}sanity, add a comment that this is the ppc .opd
1221 * section, not the ia64 .opd section.
1222 * ia64 .opd should not point to discarded sections.
1223 * [.rodata] like for .init.text we ignore .rodata references -same reason
1225 static int exit_section_ref_ok(const char *name)
1228 /* Absolute section names */
1229 const char *namelist1[] = {
1234 ".opd", /* See comment [OPD] */
1235 ".toc1", /* used by ppc64 */
1238 "__bug_table", /* used by powerpc for BUG() */
1241 ".parainstructions",
1246 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1249 /* Start of section names */
1250 const char *namelist2[] = {
1254 /* part of section name */
1255 const char *namelist3 [] = {
1256 ".unwind", /* Sample: IA_64.unwind.exit.text */
1260 for (s = namelist1; *s; s++)
1261 if (strcmp(*s, name) == 0)
1263 for (s = namelist2; *s; s++)
1264 if (strncmp(*s, name, strlen(*s)) == 0)
1266 for (s = namelist3; *s; s++)
1267 if (strstr(name, *s) != NULL)
1272 static void read_symbols(char *modname)
1274 const char *symname;
1278 struct elf_info info = { };
1281 if (!parse_elf(&info, modname))
1284 mod = new_module(modname);
1286 /* When there's no vmlinux, don't print warnings about
1287 * unresolved symbols (since there'll be too many ;) */
1288 if (is_vmlinux(modname)) {
1293 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1295 if (license_is_gpl_compatible(license))
1296 mod->gpl_compatible = 1;
1298 mod->gpl_compatible = 0;
1301 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1302 "license", license);
1305 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1306 symname = info.strtab + sym->st_name;
1308 handle_modversions(mod, &info, sym, symname);
1309 handle_moddevtable(mod, &info, sym, symname);
1311 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1312 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1314 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1316 maybe_frob_rcs_version(modname, version, info.modinfo,
1317 version - (char *)info.hdr);
1318 if (version || (all_versions && !is_vmlinux(modname)))
1319 get_src_version(modname, mod->srcversion,
1320 sizeof(mod->srcversion)-1);
1322 parse_elf_finish(&info);
1324 /* Our trick to get versioning for struct_module - it's
1325 * never passed as an argument to an exported function, so
1326 * the automatic versioning doesn't pick it up, but it's really
1327 * important anyhow */
1329 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1334 /* We first write the generated file into memory using the
1335 * following helper, then compare to the file on disk and
1336 * only update the later if anything changed */
1338 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1339 const char *fmt, ...)
1346 len = vsnprintf(tmp, SZ, fmt, ap);
1347 buf_write(buf, tmp, len);
1351 void buf_write(struct buffer *buf, const char *s, int len)
1353 if (buf->size - buf->pos < len) {
1354 buf->size += len + SZ;
1355 buf->p = realloc(buf->p, buf->size);
1357 strncpy(buf->p + buf->pos, s, len);
1361 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1363 const char *e = is_vmlinux(m) ?"":".ko";
1367 fatal("modpost: GPL-incompatible module %s%s "
1368 "uses GPL-only symbol '%s'\n", m, e, s);
1370 case export_unused_gpl:
1371 fatal("modpost: GPL-incompatible module %s%s "
1372 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1374 case export_gpl_future:
1375 warn("modpost: GPL-incompatible module %s%s "
1376 "uses future GPL-only symbol '%s'\n", m, e, s);
1380 case export_unknown:
1386 static void check_for_unused(enum export exp, const char* m, const char* s)
1388 const char *e = is_vmlinux(m) ?"":".ko";
1392 case export_unused_gpl:
1393 warn("modpost: module %s%s "
1394 "uses symbol '%s' marked UNUSED\n", m, e, s);
1402 static void check_exports(struct module *mod)
1404 struct symbol *s, *exp;
1406 for (s = mod->unres; s; s = s->next) {
1407 const char *basename;
1408 exp = find_symbol(s->name);
1409 if (!exp || exp->module == mod)
1411 basename = strrchr(mod->name, '/');
1415 basename = mod->name;
1416 if (!mod->gpl_compatible)
1417 check_for_gpl_usage(exp->export, basename, exp->name);
1418 check_for_unused(exp->export, basename, exp->name);
1423 * Header for the generated file
1425 static void add_header(struct buffer *b, struct module *mod)
1427 buf_printf(b, "#include <linux/module.h>\n");
1428 buf_printf(b, "#include <linux/vermagic.h>\n");
1429 buf_printf(b, "#include <linux/compiler.h>\n");
1430 buf_printf(b, "\n");
1431 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1432 buf_printf(b, "\n");
1433 buf_printf(b, "struct module __this_module\n");
1434 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1435 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1437 buf_printf(b, " .init = init_module,\n");
1438 if (mod->has_cleanup)
1439 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1440 " .exit = cleanup_module,\n"
1442 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1443 buf_printf(b, "};\n");
1447 * Record CRCs for unresolved symbols
1449 static int add_versions(struct buffer *b, struct module *mod)
1451 struct symbol *s, *exp;
1454 for (s = mod->unres; s; s = s->next) {
1455 exp = find_symbol(s->name);
1456 if (!exp || exp->module == mod) {
1457 if (have_vmlinux && !s->weak) {
1458 if (warn_unresolved) {
1459 warn("\"%s\" [%s.ko] undefined!\n",
1460 s->name, mod->name);
1462 merror("\"%s\" [%s.ko] undefined!\n",
1463 s->name, mod->name);
1469 s->module = exp->module;
1470 s->crc_valid = exp->crc_valid;
1477 buf_printf(b, "\n");
1478 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1479 buf_printf(b, "__attribute_used__\n");
1480 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1482 for (s = mod->unres; s; s = s->next) {
1486 if (!s->crc_valid) {
1487 warn("\"%s\" [%s.ko] has no CRC!\n",
1488 s->name, mod->name);
1491 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1494 buf_printf(b, "};\n");
1499 static void add_depends(struct buffer *b, struct module *mod,
1500 struct module *modules)
1506 for (m = modules; m; m = m->next) {
1507 m->seen = is_vmlinux(m->name);
1510 buf_printf(b, "\n");
1511 buf_printf(b, "static const char __module_depends[]\n");
1512 buf_printf(b, "__attribute_used__\n");
1513 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1514 buf_printf(b, "\"depends=");
1515 for (s = mod->unres; s; s = s->next) {
1520 if (s->module->seen)
1523 s->module->seen = 1;
1524 if ((p = strrchr(s->module->name, '/')) != NULL)
1527 p = s->module->name;
1528 buf_printf(b, "%s%s", first ? "" : ",", p);
1531 buf_printf(b, "\";\n");
1534 static void add_srcversion(struct buffer *b, struct module *mod)
1536 if (mod->srcversion[0]) {
1537 buf_printf(b, "\n");
1538 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1543 static void write_if_changed(struct buffer *b, const char *fname)
1549 file = fopen(fname, "r");
1553 if (fstat(fileno(file), &st) < 0)
1556 if (st.st_size != b->pos)
1559 tmp = NOFAIL(malloc(b->pos));
1560 if (fread(tmp, 1, b->pos, file) != b->pos)
1563 if (memcmp(tmp, b->p, b->pos) != 0)
1575 file = fopen(fname, "w");
1580 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1587 /* parse Module.symvers file. line format:
1588 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1590 static void read_dump(const char *fname, unsigned int kernel)
1592 unsigned long size, pos = 0;
1593 void *file = grab_file(fname, &size);
1597 /* No symbol versions, silently ignore */
1600 while ((line = get_next_line(&pos, file, size))) {
1601 char *symname, *modname, *d, *export, *end;
1606 if (!(symname = strchr(line, '\t')))
1609 if (!(modname = strchr(symname, '\t')))
1612 if ((export = strchr(modname, '\t')) != NULL)
1614 if (export && ((end = strchr(export, '\t')) != NULL))
1616 crc = strtoul(line, &d, 16);
1617 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1620 if (!(mod = find_module(modname))) {
1621 if (is_vmlinux(modname)) {
1624 mod = new_module(NOFAIL(strdup(modname)));
1627 s = sym_add_exported(symname, mod, export_no(export));
1630 sym_update_crc(symname, mod, crc, export_no(export));
1634 fatal("parse error in symbol dump file\n");
1637 /* For normal builds always dump all symbols.
1638 * For external modules only dump symbols
1639 * that are not read from kernel Module.symvers.
1641 static int dump_sym(struct symbol *sym)
1643 if (!external_module)
1645 if (sym->vmlinux || sym->kernel)
1650 static void write_dump(const char *fname)
1652 struct buffer buf = { };
1653 struct symbol *symbol;
1656 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1657 symbol = symbolhash[n];
1659 if (dump_sym(symbol))
1660 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1661 symbol->crc, symbol->name,
1662 symbol->module->name,
1663 export_str(symbol->export));
1664 symbol = symbol->next;
1667 write_if_changed(&buf, fname);
1670 int main(int argc, char **argv)
1673 struct buffer buf = { };
1675 char *kernel_read = NULL, *module_read = NULL;
1676 char *dump_write = NULL;
1680 while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
1683 kernel_read = optarg;
1686 module_read = optarg;
1687 external_module = 1;
1693 dump_write = optarg;
1699 warn_unresolved = 1;
1707 read_dump(kernel_read, 1);
1709 read_dump(module_read, 0);
1711 while (optind < argc) {
1712 read_symbols(argv[optind++]);
1715 for (mod = modules; mod; mod = mod->next) {
1723 for (mod = modules; mod; mod = mod->next) {
1729 add_header(&buf, mod);
1730 err |= add_versions(&buf, mod);
1731 add_depends(&buf, mod, modules);
1732 add_moddevtable(&buf, mod);
1733 add_srcversion(&buf, mod);
1735 sprintf(fname, "%s.mod.c", mod->name);
1736 write_if_changed(&buf, fname);
1740 write_dump(dump_write);