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 ...
22 #include "../../include/generated/autoconf.h"
23 #include "../../include/linux/license.h"
24 #include "../../include/linux/export.h"
26 /* Are we using CONFIG_MODVERSIONS? */
27 static int modversions = 0;
28 /* Warn about undefined symbols? (do so if we have vmlinux) */
29 static int have_vmlinux = 0;
30 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
31 static int all_versions = 0;
32 /* If we are modposting external module set to 1 */
33 static int external_module = 0;
34 /* Warn about section mismatch in vmlinux if set to 1 */
35 static int vmlinux_section_warnings = 1;
36 /* Only warn about unresolved symbols */
37 static int warn_unresolved = 0;
38 /* How a symbol is exported */
39 static int sec_mismatch_count = 0;
40 static int sec_mismatch_verbose = 1;
41 static int sec_mismatch_fatal = 0;
42 /* ignore missing files */
43 static int ignore_missing_files;
46 export_plain, export_unused, export_gpl,
47 export_unused_gpl, export_gpl_future, export_unknown
50 #define PRINTF __attribute__ ((format (printf, 1, 2)))
52 PRINTF void fatal(const char *fmt, ...)
56 fprintf(stderr, "FATAL: ");
58 va_start(arglist, fmt);
59 vfprintf(stderr, fmt, arglist);
65 PRINTF void warn(const char *fmt, ...)
69 fprintf(stderr, "WARNING: ");
71 va_start(arglist, fmt);
72 vfprintf(stderr, fmt, arglist);
76 PRINTF void merror(const char *fmt, ...)
80 fprintf(stderr, "ERROR: ");
82 va_start(arglist, fmt);
83 vfprintf(stderr, fmt, arglist);
87 static inline bool strends(const char *str, const char *postfix)
89 if (strlen(str) < strlen(postfix))
92 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
95 static int is_vmlinux(const char *modname)
99 myname = strrchr(modname, '/');
105 return (strcmp(myname, "vmlinux") == 0) ||
106 (strcmp(myname, "vmlinux.o") == 0);
109 void *do_nofail(void *ptr, const char *expr)
112 fatal("modpost: Memory allocation failure: %s.\n", expr);
117 /* A list of all modules we processed */
118 static struct module *modules;
120 static struct module *find_module(char *modname)
124 for (mod = modules; mod; mod = mod->next)
125 if (strcmp(mod->name, modname) == 0)
130 static struct module *new_module(const char *modname)
135 mod = NOFAIL(malloc(sizeof(*mod)));
136 memset(mod, 0, sizeof(*mod));
137 p = NOFAIL(strdup(modname));
139 /* strip trailing .o */
140 if (strends(p, ".o")) {
141 p[strlen(p) - 2] = '\0';
147 mod->gpl_compatible = -1;
154 /* A hash of all exported symbols,
155 * struct symbol is also used for lists of unresolved symbols */
157 #define SYMBOL_HASH_SIZE 1024
161 struct module *module;
165 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
166 unsigned int kernel:1; /* 1 if symbol is from kernel
167 * (only for external modules) **/
168 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
169 enum export export; /* Type of export */
173 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
175 /* This is based on the hash agorithm from gdbm, via tdb */
176 static inline unsigned int tdb_hash(const char *name)
178 unsigned value; /* Used to compute the hash value. */
179 unsigned i; /* Used to cycle through random values. */
181 /* Set the initial value from the key size. */
182 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
183 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
185 return (1103515243 * value + 12345);
189 * Allocate a new symbols for use in the hash of exported symbols or
190 * the list of unresolved symbols per module
192 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
195 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
197 memset(s, 0, sizeof(*s));
198 strcpy(s->name, name);
204 /* For the hash of exported symbols */
205 static struct symbol *new_symbol(const char *name, struct module *module,
211 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
212 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
213 new->module = module;
214 new->export = export;
218 static struct symbol *find_symbol(const char *name)
222 /* For our purposes, .foo matches foo. PPC64 needs this. */
226 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
227 if (strcmp(s->name, name) == 0)
233 static const struct {
237 { .str = "EXPORT_SYMBOL", .export = export_plain },
238 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
239 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
240 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
241 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
242 { .str = "(unknown)", .export = export_unknown },
246 static const char *export_str(enum export ex)
248 return export_list[ex].str;
251 static enum export export_no(const char *s)
256 return export_unknown;
257 for (i = 0; export_list[i].export != export_unknown; i++) {
258 if (strcmp(export_list[i].str, s) == 0)
259 return export_list[i].export;
261 return export_unknown;
264 static const char *sec_name(struct elf_info *elf, int secindex);
266 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
268 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
270 const char *secname = sec_name(elf, sec);
272 if (strstarts(secname, "___ksymtab+"))
274 else if (strstarts(secname, "___ksymtab_unused+"))
275 return export_unused;
276 else if (strstarts(secname, "___ksymtab_gpl+"))
278 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
279 return export_unused_gpl;
280 else if (strstarts(secname, "___ksymtab_gpl_future+"))
281 return export_gpl_future;
283 return export_unknown;
286 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
288 if (sec == elf->export_sec)
290 else if (sec == elf->export_unused_sec)
291 return export_unused;
292 else if (sec == elf->export_gpl_sec)
294 else if (sec == elf->export_unused_gpl_sec)
295 return export_unused_gpl;
296 else if (sec == elf->export_gpl_future_sec)
297 return export_gpl_future;
299 return export_unknown;
303 * Add an exported symbol - it may have already been added without a
304 * CRC, in this case just update the CRC
306 static struct symbol *sym_add_exported(const char *name, struct module *mod,
309 struct symbol *s = find_symbol(name);
312 s = new_symbol(name, mod, export);
315 warn("%s: '%s' exported twice. Previous export "
316 "was in %s%s\n", mod->name, name,
318 is_vmlinux(s->module->name) ?"":".ko");
320 /* In case Module.symvers was out of date */
325 s->vmlinux = is_vmlinux(mod->name);
331 static void sym_update_crc(const char *name, struct module *mod,
332 unsigned int crc, enum export export)
334 struct symbol *s = find_symbol(name);
337 s = new_symbol(name, mod, export);
338 /* Don't complain when we find it later. */
345 void *grab_file(const char *filename, unsigned long *size)
348 void *map = MAP_FAILED;
351 fd = open(filename, O_RDONLY);
358 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
362 if (map == MAP_FAILED)
368 * Return a copy of the next line in a mmap'ed file.
369 * spaces in the beginning of the line is trimmed away.
370 * Return a pointer to a static buffer.
372 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
374 static char line[4096];
377 signed char *p = (signed char *)file + *pos;
380 for (; *pos < size ; (*pos)++) {
381 if (skip && isspace(*p)) {
386 if (*p != '\n' && (*pos < size)) {
390 break; /* Too long, stop */
401 void release_file(void *file, unsigned long size)
406 static int parse_elf(struct elf_info *info, const char *filename)
412 const char *secstrings;
413 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
415 hdr = grab_file(filename, &info->size);
417 if (ignore_missing_files) {
418 fprintf(stderr, "%s: %s (ignored)\n", filename,
426 if (info->size < sizeof(*hdr)) {
427 /* file too small, assume this is an empty .o file */
430 /* Is this a valid ELF file? */
431 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
432 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
433 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
434 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
435 /* Not an ELF file - silently ignore it */
438 /* Fix endianness in ELF header */
439 hdr->e_type = TO_NATIVE(hdr->e_type);
440 hdr->e_machine = TO_NATIVE(hdr->e_machine);
441 hdr->e_version = TO_NATIVE(hdr->e_version);
442 hdr->e_entry = TO_NATIVE(hdr->e_entry);
443 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
444 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
445 hdr->e_flags = TO_NATIVE(hdr->e_flags);
446 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
447 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
448 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
449 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
450 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
451 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
452 sechdrs = (void *)hdr + hdr->e_shoff;
453 info->sechdrs = sechdrs;
455 /* Check if file offset is correct */
456 if (hdr->e_shoff > info->size) {
457 fatal("section header offset=%lu in file '%s' is bigger than "
458 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
459 filename, info->size);
463 if (hdr->e_shnum == SHN_UNDEF) {
465 * There are more than 64k sections,
466 * read count from .sh_size.
468 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
471 info->num_sections = hdr->e_shnum;
473 if (hdr->e_shstrndx == SHN_XINDEX) {
474 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
477 info->secindex_strings = hdr->e_shstrndx;
480 /* Fix endianness in section headers */
481 for (i = 0; i < info->num_sections; i++) {
482 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
483 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
484 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
485 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
486 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
487 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
488 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
489 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
490 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
491 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
493 /* Find symbol table. */
494 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
495 for (i = 1; i < info->num_sections; i++) {
497 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
499 if (!nobits && sechdrs[i].sh_offset > info->size) {
500 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
501 "sizeof(*hrd)=%zu\n", filename,
502 (unsigned long)sechdrs[i].sh_offset,
506 secname = secstrings + sechdrs[i].sh_name;
507 if (strcmp(secname, ".modinfo") == 0) {
509 fatal("%s has NOBITS .modinfo\n", filename);
510 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
511 info->modinfo_len = sechdrs[i].sh_size;
512 } else if (strcmp(secname, "__ksymtab") == 0)
513 info->export_sec = i;
514 else if (strcmp(secname, "__ksymtab_unused") == 0)
515 info->export_unused_sec = i;
516 else if (strcmp(secname, "__ksymtab_gpl") == 0)
517 info->export_gpl_sec = i;
518 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
519 info->export_unused_gpl_sec = i;
520 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
521 info->export_gpl_future_sec = i;
523 if (sechdrs[i].sh_type == SHT_SYMTAB) {
524 unsigned int sh_link_idx;
526 info->symtab_start = (void *)hdr +
527 sechdrs[i].sh_offset;
528 info->symtab_stop = (void *)hdr +
529 sechdrs[i].sh_offset + sechdrs[i].sh_size;
530 sh_link_idx = sechdrs[i].sh_link;
531 info->strtab = (void *)hdr +
532 sechdrs[sh_link_idx].sh_offset;
535 /* 32bit section no. table? ("more than 64k sections") */
536 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
537 symtab_shndx_idx = i;
538 info->symtab_shndx_start = (void *)hdr +
539 sechdrs[i].sh_offset;
540 info->symtab_shndx_stop = (void *)hdr +
541 sechdrs[i].sh_offset + sechdrs[i].sh_size;
544 if (!info->symtab_start)
545 fatal("%s has no symtab?\n", filename);
547 /* Fix endianness in symbols */
548 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
549 sym->st_shndx = TO_NATIVE(sym->st_shndx);
550 sym->st_name = TO_NATIVE(sym->st_name);
551 sym->st_value = TO_NATIVE(sym->st_value);
552 sym->st_size = TO_NATIVE(sym->st_size);
555 if (symtab_shndx_idx != ~0U) {
557 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
558 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
559 filename, sechdrs[symtab_shndx_idx].sh_link,
562 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
570 static void parse_elf_finish(struct elf_info *info)
572 release_file(info->hdr, info->size);
575 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
577 /* ignore __this_module, it will be resolved shortly */
578 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
580 /* ignore global offset table */
581 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
583 if (info->hdr->e_machine == EM_PPC)
584 /* Special register function linked on all modules during final link of .ko */
585 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
586 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
587 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
588 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
589 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
590 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
592 if (info->hdr->e_machine == EM_PPC64)
593 /* Special register function linked on all modules during final link of .ko */
594 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
595 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
596 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
597 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
598 strcmp(symname, ".TOC.") == 0)
600 /* Do not ignore this symbol */
604 #define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
605 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
607 static void handle_modversions(struct module *mod, struct elf_info *info,
608 Elf_Sym *sym, const char *symname)
614 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
615 strncmp(symname, "__ksymtab", 9) == 0)
616 export = export_from_secname(info, get_secindex(info, sym));
618 export = export_from_sec(info, get_secindex(info, sym));
621 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
623 crc = (unsigned int) sym->st_value;
624 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
627 /* symbol points to the CRC in the ELF object */
628 crcp = (void *)info->hdr + sym->st_value +
629 info->sechdrs[sym->st_shndx].sh_offset -
630 (info->hdr->e_type != ET_REL ?
631 info->sechdrs[sym->st_shndx].sh_addr : 0);
634 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
638 switch (sym->st_shndx) {
640 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
641 /* Should warn here, but modpost runs before the linker */
643 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
646 /* undefined symbol */
647 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
648 ELF_ST_BIND(sym->st_info) != STB_WEAK)
650 if (ignore_undef_symbol(info, symname))
652 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
653 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
654 /* add compatibility with older glibc */
655 #ifndef STT_SPARC_REGISTER
656 #define STT_SPARC_REGISTER STT_REGISTER
658 if (info->hdr->e_machine == EM_SPARC ||
659 info->hdr->e_machine == EM_SPARCV9) {
660 /* Ignore register directives. */
661 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
663 if (symname[0] == '.') {
664 char *munged = strdup(symname);
666 munged[1] = toupper(munged[1]);
672 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
673 if (symname[0] != '_')
679 const char *e = is_vmlinux(mod->name) ?"":".ko";
680 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
682 mod->unres = alloc_symbol(symname,
683 ELF_ST_BIND(sym->st_info) == STB_WEAK,
687 /* All exported symbols */
688 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
689 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
692 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
694 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
695 mod->has_cleanup = 1;
701 * Parse tag=value strings from .modinfo section
703 static char *next_string(char *string, unsigned long *secsize)
705 /* Skip non-zero chars */
708 if ((*secsize)-- <= 1)
712 /* Skip any zero padding. */
715 if ((*secsize)-- <= 1)
721 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
722 const char *tag, char *info)
725 unsigned int taglen = strlen(tag);
726 unsigned long size = modinfo_len;
729 size -= info - (char *)modinfo;
730 modinfo = next_string(info, &size);
733 for (p = modinfo; p; p = next_string(p, &size)) {
734 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
735 return p + taglen + 1;
740 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
744 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
748 * Test if string s ends in string sub
751 static int strrcmp(const char *s, const char *sub)
759 sublen = strlen(sub);
761 if ((slen == 0) || (sublen == 0))
767 return memcmp(s + slen - sublen, sub, sublen);
770 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
773 return elf->strtab + sym->st_name;
778 static const char *sec_name(struct elf_info *elf, int secindex)
780 Elf_Shdr *sechdrs = elf->sechdrs;
781 return (void *)elf->hdr +
782 elf->sechdrs[elf->secindex_strings].sh_offset +
783 sechdrs[secindex].sh_name;
786 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
788 return (void *)elf->hdr +
789 elf->sechdrs[elf->secindex_strings].sh_offset +
793 /* The pattern is an array of simple patterns.
794 * "foo" will match an exact string equal to "foo"
795 * "*foo" will match a string that ends with "foo"
796 * "foo*" will match a string that begins with "foo"
797 * "*foo*" will match a string that contains "foo"
799 static int match(const char *sym, const char * const pat[])
804 const char *endp = p + strlen(p) - 1;
807 if (*p == '*' && *endp == '*') {
808 char *here, *bare = strndup(p + 1, strlen(p) - 2);
810 here = strstr(sym, bare);
816 else if (*p == '*') {
817 if (strrcmp(sym, p + 1) == 0)
821 else if (*endp == '*') {
822 if (strncmp(sym, p, strlen(p) - 1) == 0)
827 if (strcmp(p, sym) == 0)
835 /* sections that we do not want to do full section mismatch check on */
836 static const char *const section_white_list[] =
840 ".cranges", /* sh64 */
841 ".zdebug*", /* Compressed debug sections. */
842 ".GCC-command-line", /* mn10300 */
843 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
844 ".mdebug*", /* alpha, score, mips etc. */
845 ".pdr", /* alpha, score, mips etc. */
850 ".xt.prop", /* xtensa */
851 ".xt.lit", /* xtensa */
852 ".arcextmap*", /* arc */
853 ".gnu.linkonce.arcext*", /* arc : modules */
854 ".cmem*", /* EZchip */
855 ".fmt_slot*", /* EZchip */
861 * This is used to find sections missing the SHF_ALLOC flag.
862 * The cause of this is often a section specified in assembler
863 * without "ax" / "aw".
865 static void check_section(const char *modname, struct elf_info *elf,
868 const char *sec = sech_name(elf, sechdr);
870 if (sechdr->sh_type == SHT_PROGBITS &&
871 !(sechdr->sh_flags & SHF_ALLOC) &&
872 !match(sec, section_white_list)) {
873 warn("%s (%s): unexpected non-allocatable section.\n"
874 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
875 "Note that for example <linux/init.h> contains\n"
876 "section definitions for use in .S files.\n\n",
883 #define ALL_INIT_DATA_SECTIONS \
884 ".init.setup", ".init.rodata", ".meminit.rodata", \
885 ".init.data", ".meminit.data"
886 #define ALL_EXIT_DATA_SECTIONS \
887 ".exit.data", ".memexit.data"
889 #define ALL_INIT_TEXT_SECTIONS \
890 ".init.text", ".meminit.text"
891 #define ALL_EXIT_TEXT_SECTIONS \
892 ".exit.text", ".memexit.text"
894 #define ALL_PCI_INIT_SECTIONS \
895 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
896 ".pci_fixup_enable", ".pci_fixup_resume", \
897 ".pci_fixup_resume_early", ".pci_fixup_suspend"
899 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
900 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
902 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
903 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
905 #define DATA_SECTIONS ".data", ".data.rel"
906 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
907 ".kprobes.text", ".cpuidle.text"
908 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
909 ".fixup", ".entry.text", ".exception.text", ".text.*", \
912 #define INIT_SECTIONS ".init.*"
913 #define MEM_INIT_SECTIONS ".meminit.*"
915 #define EXIT_SECTIONS ".exit.*"
916 #define MEM_EXIT_SECTIONS ".memexit.*"
918 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
919 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
921 /* init data sections */
922 static const char *const init_data_sections[] =
923 { ALL_INIT_DATA_SECTIONS, NULL };
925 /* all init sections */
926 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
928 /* All init and exit sections (code + data) */
929 static const char *const init_exit_sections[] =
930 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
932 /* all text sections */
933 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
936 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
939 /* symbols in .data that may refer to init/exit sections */
940 #define DEFAULT_SYMBOL_WHITE_LIST \
942 "*_template", /* scsi uses *_template a lot */ \
943 "*_timer", /* arm uses ops structures named _timer a lot */ \
944 "*_sht", /* scsi also used *_sht to some extent */ \
950 static const char *const head_sections[] = { ".head.text*", NULL };
951 static const char *const linker_symbols[] =
952 { "__init_begin", "_sinittext", "_einittext", NULL };
953 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
960 XXXINIT_TO_SOME_INIT,
961 XXXEXIT_TO_SOME_EXIT,
962 ANY_INIT_TO_ANY_EXIT,
963 ANY_EXIT_TO_ANY_INIT,
969 * Describe how to match sections on different criterias:
971 * @fromsec: Array of sections to be matched.
973 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
974 * this array is forbidden (black-list). Can be empty.
976 * @good_tosec: Relocations applied to a section in @fromsec must be
977 * targetting sections in this array (white-list). Can be empty.
979 * @mismatch: Type of mismatch.
981 * @symbol_white_list: Do not match a relocation to a symbol in this list
982 * even if it is targetting a section in @bad_to_sec.
984 * @handler: Specific handler to call when a match is found. If NULL,
985 * default_mismatch_handler() will be called.
988 struct sectioncheck {
989 const char *fromsec[20];
990 const char *bad_tosec[20];
991 const char *good_tosec[20];
992 enum mismatch mismatch;
993 const char *symbol_white_list[20];
994 void (*handler)(const char *modname, struct elf_info *elf,
995 const struct sectioncheck* const mismatch,
996 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1000 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1001 const struct sectioncheck* const mismatch,
1002 Elf_Rela *r, Elf_Sym *sym,
1003 const char *fromsec);
1005 static const struct sectioncheck sectioncheck[] = {
1006 /* Do not reference init/exit code/data from
1007 * normal code and data
1010 .fromsec = { TEXT_SECTIONS, NULL },
1011 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1012 .mismatch = TEXT_TO_ANY_INIT,
1013 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1016 .fromsec = { DATA_SECTIONS, NULL },
1017 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1018 .mismatch = DATA_TO_ANY_INIT,
1019 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1022 .fromsec = { DATA_SECTIONS, NULL },
1023 .bad_tosec = { INIT_SECTIONS, NULL },
1024 .mismatch = DATA_TO_ANY_INIT,
1025 .symbol_white_list = {
1026 "*_template", "*_timer", "*_sht", "*_ops",
1027 "*_probe", "*_probe_one", "*_console", NULL
1031 .fromsec = { TEXT_SECTIONS, NULL },
1032 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1033 .mismatch = TEXT_TO_ANY_EXIT,
1034 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1037 .fromsec = { DATA_SECTIONS, NULL },
1038 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1039 .mismatch = DATA_TO_ANY_EXIT,
1040 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1042 /* Do not reference init code/data from meminit code/data */
1044 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1045 .bad_tosec = { INIT_SECTIONS, NULL },
1046 .mismatch = XXXINIT_TO_SOME_INIT,
1047 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1049 /* Do not reference exit code/data from memexit code/data */
1051 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1052 .bad_tosec = { EXIT_SECTIONS, NULL },
1053 .mismatch = XXXEXIT_TO_SOME_EXIT,
1054 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1056 /* Do not use exit code/data from init code */
1058 .fromsec = { ALL_INIT_SECTIONS, NULL },
1059 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1060 .mismatch = ANY_INIT_TO_ANY_EXIT,
1061 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1063 /* Do not use init code/data from exit code */
1065 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1066 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1067 .mismatch = ANY_EXIT_TO_ANY_INIT,
1068 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1071 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1072 .bad_tosec = { INIT_SECTIONS, NULL },
1073 .mismatch = ANY_INIT_TO_ANY_EXIT,
1074 .symbol_white_list = { NULL },
1076 /* Do not export init/exit functions or data */
1078 .fromsec = { "__ksymtab*", NULL },
1079 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1080 .mismatch = EXPORT_TO_INIT_EXIT,
1081 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1084 .fromsec = { "__ex_table", NULL },
1085 /* If you're adding any new black-listed sections in here, consider
1086 * adding a special 'printer' for them in scripts/check_extable.
1088 .bad_tosec = { ".altinstr_replacement", NULL },
1089 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1090 .mismatch = EXTABLE_TO_NON_TEXT,
1091 .handler = extable_mismatch_handler,
1095 static const struct sectioncheck *section_mismatch(
1096 const char *fromsec, const char *tosec)
1099 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1100 const struct sectioncheck *check = §ioncheck[0];
1103 * The target section could be the SHT_NUL section when we're
1104 * handling relocations to un-resolved symbols, trying to match it
1105 * doesn't make much sense and causes build failures on parisc and
1106 * mn10300 architectures.
1111 for (i = 0; i < elems; i++) {
1112 if (match(fromsec, check->fromsec)) {
1113 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1115 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1124 * Whitelist to allow certain references to pass with no warning.
1127 * If a module parameter is declared __initdata and permissions=0
1128 * then this is legal despite the warning generated.
1129 * We cannot see value of permissions here, so just ignore
1131 * The pattern is identified by:
1132 * tosec = .init.data
1137 * module_param_call() ops can refer to __init set function if permissions=0
1138 * The pattern is identified by:
1139 * tosec = .init.text
1141 * atsym = __param_ops_*
1144 * Many drivers utilise a *driver container with references to
1145 * add, remove, probe functions etc.
1146 * the pattern is identified by:
1147 * tosec = init or exit section
1148 * fromsec = data section
1149 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1150 * *probe_one, *_console, *_timer
1153 * Whitelist all references from .head.text to any init section
1156 * Some symbols belong to init section but still it is ok to reference
1157 * these from non-init sections as these symbols don't have any memory
1158 * allocated for them and symbol address and value are same. So even
1159 * if init section is freed, its ok to reference those symbols.
1160 * For ex. symbols marking the init section boundaries.
1161 * This pattern is identified by
1162 * refsymname = __init_begin, _sinittext, _einittext
1165 * GCC may optimize static inlines when fed constant arg(s) resulting
1166 * in functions like cpumask_empty() -- generating an associated symbol
1167 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1168 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1169 * meaningless section warning. May need to add isra symbols too...
1170 * This pattern is identified by
1171 * tosec = init section
1172 * fromsec = text section
1173 * refsymname = *.constprop.*
1176 static int secref_whitelist(const struct sectioncheck *mismatch,
1177 const char *fromsec, const char *fromsym,
1178 const char *tosec, const char *tosym)
1180 /* Check for pattern 1 */
1181 if (match(tosec, init_data_sections) &&
1182 match(fromsec, data_sections) &&
1183 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1186 /* Check for pattern 1a */
1187 if (strcmp(tosec, ".init.text") == 0 &&
1188 match(fromsec, data_sections) &&
1189 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1192 /* Check for pattern 2 */
1193 if (match(tosec, init_exit_sections) &&
1194 match(fromsec, data_sections) &&
1195 match(fromsym, mismatch->symbol_white_list))
1198 /* Check for pattern 3 */
1199 if (match(fromsec, head_sections) &&
1200 match(tosec, init_sections))
1203 /* Check for pattern 4 */
1204 if (match(tosym, linker_symbols))
1207 /* Check for pattern 5 */
1208 if (match(fromsec, text_sections) &&
1209 match(tosec, init_sections) &&
1210 match(fromsym, optim_symbols))
1217 * Find symbol based on relocation record info.
1218 * In some cases the symbol supplied is a valid symbol so
1219 * return refsym. If st_name != 0 we assume this is a valid symbol.
1220 * In other cases the symbol needs to be looked up in the symbol table
1221 * based on section and address.
1223 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1227 Elf_Sym *near = NULL;
1228 Elf64_Sword distance = 20;
1230 unsigned int relsym_secindex;
1232 if (relsym->st_name != 0)
1235 relsym_secindex = get_secindex(elf, relsym);
1236 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1237 if (get_secindex(elf, sym) != relsym_secindex)
1239 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1241 if (sym->st_value == addr)
1243 /* Find a symbol nearby - addr are maybe negative */
1244 d = sym->st_value - addr;
1246 d = addr - sym->st_value;
1252 /* We need a close match */
1259 static inline int is_arm_mapping_symbol(const char *str)
1261 return str[0] == '$' && strchr("axtd", str[1])
1262 && (str[2] == '\0' || str[2] == '.');
1266 * If there's no name there, ignore it; likewise, ignore it if it's
1267 * one of the magic symbols emitted used by current ARM tools.
1269 * Otherwise if find_symbols_between() returns those symbols, they'll
1270 * fail the whitelist tests and cause lots of false alarms ... fixable
1271 * only by merging __exit and __init sections into __text, bloating
1272 * the kernel (which is especially evil on embedded platforms).
1274 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1276 const char *name = elf->strtab + sym->st_name;
1278 if (!name || !strlen(name))
1280 return !is_arm_mapping_symbol(name);
1284 * Find symbols before or equal addr and after addr - in the section sec.
1285 * If we find two symbols with equal offset prefer one with a valid name.
1286 * The ELF format may have a better way to detect what type of symbol
1287 * it is, but this works for now.
1289 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1293 Elf_Sym *near = NULL;
1294 Elf_Addr distance = ~0;
1296 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1299 if (is_shndx_special(sym->st_shndx))
1301 symsec = sec_name(elf, get_secindex(elf, sym));
1302 if (strcmp(symsec, sec) != 0)
1304 if (!is_valid_name(elf, sym))
1306 if (sym->st_value <= addr) {
1307 if ((addr - sym->st_value) < distance) {
1308 distance = addr - sym->st_value;
1310 } else if ((addr - sym->st_value) == distance) {
1319 * Convert a section name to the function/data attribute
1320 * .init.text => __init
1321 * .memexitconst => __memconst
1324 * The memory of returned value has been allocated on a heap. The user of this
1325 * method should free it after usage.
1327 static char *sec2annotation(const char *s)
1329 if (match(s, init_exit_sections)) {
1330 char *p = malloc(20);
1337 while (*s && *s != '.')
1342 if (strstr(s, "rodata") != NULL)
1343 strcat(p, "const ");
1344 else if (strstr(s, "data") != NULL)
1354 static int is_function(Elf_Sym *sym)
1357 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1362 static void print_section_list(const char * const list[20])
1364 const char *const *s = list;
1367 fprintf(stderr, "%s", *s);
1370 fprintf(stderr, ", ");
1372 fprintf(stderr, "\n");
1375 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1378 case 0: *name = "variable"; *name_p = ""; break;
1379 case 1: *name = "function"; *name_p = "()"; break;
1380 default: *name = "(unknown reference)"; *name_p = ""; break;
1385 * Print a warning about a section mismatch.
1386 * Try to find symbols near it so user can find it.
1387 * Check whitelist before warning - it may be a false positive.
1389 static void report_sec_mismatch(const char *modname,
1390 const struct sectioncheck *mismatch,
1391 const char *fromsec,
1392 unsigned long long fromaddr,
1393 const char *fromsym,
1395 const char *tosec, const char *tosym,
1398 const char *from, *from_p;
1399 const char *to, *to_p;
1403 sec_mismatch_count++;
1404 if (!sec_mismatch_verbose)
1407 get_pretty_name(from_is_func, &from, &from_p);
1408 get_pretty_name(to_is_func, &to, &to_p);
1410 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1411 "to the %s %s:%s%s\n",
1412 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1415 switch (mismatch->mismatch) {
1416 case TEXT_TO_ANY_INIT:
1417 prl_from = sec2annotation(fromsec);
1418 prl_to = sec2annotation(tosec);
1420 "The function %s%s() references\n"
1422 "This is often because %s lacks a %s\n"
1423 "annotation or the annotation of %s is wrong.\n",
1425 to, prl_to, tosym, to_p,
1426 fromsym, prl_to, tosym);
1430 case DATA_TO_ANY_INIT: {
1431 prl_to = sec2annotation(tosec);
1433 "The variable %s references\n"
1435 "If the reference is valid then annotate the\n"
1436 "variable with __init* or __refdata (see linux/init.h) "
1437 "or name the variable:\n",
1438 fromsym, to, prl_to, tosym, to_p);
1439 print_section_list(mismatch->symbol_white_list);
1443 case TEXT_TO_ANY_EXIT:
1444 prl_to = sec2annotation(tosec);
1446 "The function %s() references a %s in an exit section.\n"
1447 "Often the %s %s%s has valid usage outside the exit section\n"
1448 "and the fix is to remove the %sannotation of %s.\n",
1449 fromsym, to, to, tosym, to_p, prl_to, tosym);
1452 case DATA_TO_ANY_EXIT: {
1453 prl_to = sec2annotation(tosec);
1455 "The variable %s references\n"
1457 "If the reference is valid then annotate the\n"
1458 "variable with __exit* (see linux/init.h) or "
1459 "name the variable:\n",
1460 fromsym, to, prl_to, tosym, to_p);
1461 print_section_list(mismatch->symbol_white_list);
1465 case XXXINIT_TO_SOME_INIT:
1466 case XXXEXIT_TO_SOME_EXIT:
1467 prl_from = sec2annotation(fromsec);
1468 prl_to = sec2annotation(tosec);
1470 "The %s %s%s%s references\n"
1472 "If %s is only used by %s then\n"
1473 "annotate %s with a matching annotation.\n",
1474 from, prl_from, fromsym, from_p,
1475 to, prl_to, tosym, to_p,
1476 tosym, fromsym, tosym);
1480 case ANY_INIT_TO_ANY_EXIT:
1481 prl_from = sec2annotation(fromsec);
1482 prl_to = sec2annotation(tosec);
1484 "The %s %s%s%s references\n"
1486 "This is often seen when error handling "
1487 "in the init function\n"
1488 "uses functionality in the exit path.\n"
1489 "The fix is often to remove the %sannotation of\n"
1490 "%s%s so it may be used outside an exit section.\n",
1491 from, prl_from, fromsym, from_p,
1492 to, prl_to, tosym, to_p,
1493 prl_to, tosym, to_p);
1497 case ANY_EXIT_TO_ANY_INIT:
1498 prl_from = sec2annotation(fromsec);
1499 prl_to = sec2annotation(tosec);
1501 "The %s %s%s%s references\n"
1503 "This is often seen when error handling "
1504 "in the exit function\n"
1505 "uses functionality in the init path.\n"
1506 "The fix is often to remove the %sannotation of\n"
1507 "%s%s so it may be used outside an init section.\n",
1508 from, prl_from, fromsym, from_p,
1509 to, prl_to, tosym, to_p,
1510 prl_to, tosym, to_p);
1514 case EXPORT_TO_INIT_EXIT:
1515 prl_to = sec2annotation(tosec);
1517 "The symbol %s is exported and annotated %s\n"
1518 "Fix this by removing the %sannotation of %s "
1519 "or drop the export.\n",
1520 tosym, prl_to, prl_to, tosym);
1523 case EXTABLE_TO_NON_TEXT:
1524 fatal("There's a special handler for this mismatch type, "
1525 "we should never get here.");
1528 fprintf(stderr, "\n");
1531 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1532 const struct sectioncheck* const mismatch,
1533 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1539 const char *fromsym;
1541 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1542 fromsym = sym_name(elf, from);
1544 if (!strncmp(fromsym, "reference___initcall",
1545 sizeof("reference___initcall")-1))
1548 tosec = sec_name(elf, get_secindex(elf, sym));
1549 to = find_elf_symbol(elf, r->r_addend, sym);
1550 tosym = sym_name(elf, to);
1552 /* check whitelist - we may ignore it */
1553 if (secref_whitelist(mismatch,
1554 fromsec, fromsym, tosec, tosym)) {
1555 report_sec_mismatch(modname, mismatch,
1556 fromsec, r->r_offset, fromsym,
1557 is_function(from), tosec, tosym,
1562 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1564 if (section_index > elf->num_sections)
1565 fatal("section_index is outside elf->num_sections!\n");
1567 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1571 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1572 * to know the sizeof(struct exception_table_entry) for the target architecture.
1574 static unsigned int extable_entry_size = 0;
1575 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1578 * If we're currently checking the second relocation within __ex_table,
1579 * that relocation offset tells us the offsetof(struct
1580 * exception_table_entry, fixup) which is equal to sizeof(struct
1581 * exception_table_entry) divided by two. We use that to our advantage
1582 * since there's no portable way to get that size as every architecture
1583 * seems to go with different sized types. Not pretty but better than
1584 * hard-coding the size for every architecture..
1586 if (!extable_entry_size)
1587 extable_entry_size = r->r_offset * 2;
1590 static inline bool is_extable_fault_address(Elf_Rela *r)
1593 * extable_entry_size is only discovered after we've handled the
1594 * _second_ relocation in __ex_table, so only abort when we're not
1595 * handling the first reloc and extable_entry_size is zero.
1597 if (r->r_offset && extable_entry_size == 0)
1598 fatal("extable_entry size hasn't been discovered!\n");
1600 return ((r->r_offset == 0) ||
1601 (r->r_offset % extable_entry_size == 0));
1604 #define is_second_extable_reloc(Start, Cur, Sec) \
1605 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1607 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1608 const struct sectioncheck* const mismatch,
1609 Elf_Rela* r, Elf_Sym* sym,
1610 const char* fromsec, const char* tosec)
1612 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1613 const char* fromsym_name = sym_name(elf, fromsym);
1614 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1615 const char* tosym_name = sym_name(elf, tosym);
1616 const char* from_pretty_name;
1617 const char* from_pretty_name_p;
1618 const char* to_pretty_name;
1619 const char* to_pretty_name_p;
1621 get_pretty_name(is_function(fromsym),
1622 &from_pretty_name, &from_pretty_name_p);
1623 get_pretty_name(is_function(tosym),
1624 &to_pretty_name, &to_pretty_name_p);
1626 warn("%s(%s+0x%lx): Section mismatch in reference"
1627 " from the %s %s%s to the %s %s:%s%s\n",
1628 modname, fromsec, (long)r->r_offset, from_pretty_name,
1629 fromsym_name, from_pretty_name_p,
1630 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1632 if (!match(tosec, mismatch->bad_tosec) &&
1633 is_executable_section(elf, get_secindex(elf, sym)))
1635 "The relocation at %s+0x%lx references\n"
1636 "section \"%s\" which is not in the list of\n"
1637 "authorized sections. If you're adding a new section\n"
1638 "and/or if this reference is valid, add \"%s\" to the\n"
1639 "list of authorized sections to jump to on fault.\n"
1640 "This can be achieved by adding \"%s\" to \n"
1641 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1642 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1645 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1646 const struct sectioncheck* const mismatch,
1647 Elf_Rela* r, Elf_Sym* sym,
1648 const char *fromsec)
1650 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1652 sec_mismatch_count++;
1654 if (sec_mismatch_verbose)
1655 report_extable_warnings(modname, elf, mismatch, r, sym,
1658 if (match(tosec, mismatch->bad_tosec))
1659 fatal("The relocation at %s+0x%lx references\n"
1660 "section \"%s\" which is black-listed.\n"
1661 "Something is seriously wrong and should be fixed.\n"
1662 "You might get more information about where this is\n"
1663 "coming from by using scripts/check_extable.sh %s\n",
1664 fromsec, (long)r->r_offset, tosec, modname);
1665 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1666 if (is_extable_fault_address(r))
1667 fatal("The relocation at %s+0x%lx references\n"
1668 "section \"%s\" which is not executable, IOW\n"
1669 "it is not possible for the kernel to fault\n"
1670 "at that address. Something is seriously wrong\n"
1671 "and should be fixed.\n",
1672 fromsec, (long)r->r_offset, tosec);
1674 fatal("The relocation at %s+0x%lx references\n"
1675 "section \"%s\" which is not executable, IOW\n"
1676 "the kernel will fault if it ever tries to\n"
1677 "jump to it. Something is seriously wrong\n"
1678 "and should be fixed.\n",
1679 fromsec, (long)r->r_offset, tosec);
1683 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1684 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1686 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1687 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1690 if (mismatch->handler)
1691 mismatch->handler(modname, elf, mismatch,
1694 default_mismatch_handler(modname, elf, mismatch,
1699 static unsigned int *reloc_location(struct elf_info *elf,
1700 Elf_Shdr *sechdr, Elf_Rela *r)
1702 Elf_Shdr *sechdrs = elf->sechdrs;
1703 int section = sechdr->sh_info;
1705 return (void *)elf->hdr + sechdrs[section].sh_offset +
1709 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1711 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1712 unsigned int *location = reloc_location(elf, sechdr, r);
1716 r->r_addend = TO_NATIVE(*location);
1719 r->r_addend = TO_NATIVE(*location) + 4;
1720 /* For CONFIG_RELOCATABLE=y */
1721 if (elf->hdr->e_type == ET_EXEC)
1722 r->r_addend += r->r_offset;
1729 #define R_ARM_CALL 28
1731 #ifndef R_ARM_JUMP24
1732 #define R_ARM_JUMP24 29
1735 #ifndef R_ARM_THM_CALL
1736 #define R_ARM_THM_CALL 10
1738 #ifndef R_ARM_THM_JUMP24
1739 #define R_ARM_THM_JUMP24 30
1741 #ifndef R_ARM_THM_JUMP19
1742 #define R_ARM_THM_JUMP19 51
1745 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1747 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1751 /* From ARM ABI: (S + A) | T */
1752 r->r_addend = (int)(long)
1753 (elf->symtab_start + ELF_R_SYM(r->r_info));
1758 case R_ARM_THM_CALL:
1759 case R_ARM_THM_JUMP24:
1760 case R_ARM_THM_JUMP19:
1761 /* From ARM ABI: ((S + A) | T) - P */
1762 r->r_addend = (int)(long)(elf->hdr +
1764 (r->r_offset - sechdr->sh_addr));
1772 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1774 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1775 unsigned int *location = reloc_location(elf, sechdr, r);
1778 if (r_typ == R_MIPS_HI16)
1779 return 1; /* skip this */
1780 inst = TO_NATIVE(*location);
1783 r->r_addend = inst & 0xffff;
1786 r->r_addend = (inst & 0x03ffffff) << 2;
1795 static void section_rela(const char *modname, struct elf_info *elf,
1802 const char *fromsec;
1804 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1805 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1807 fromsec = sech_name(elf, sechdr);
1808 fromsec += strlen(".rela");
1809 /* if from section (name) is know good then skip it */
1810 if (match(fromsec, section_white_list))
1813 for (rela = start; rela < stop; rela++) {
1814 r.r_offset = TO_NATIVE(rela->r_offset);
1815 #if KERNEL_ELFCLASS == ELFCLASS64
1816 if (elf->hdr->e_machine == EM_MIPS) {
1818 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1819 r_sym = TO_NATIVE(r_sym);
1820 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1821 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1823 r.r_info = TO_NATIVE(rela->r_info);
1824 r_sym = ELF_R_SYM(r.r_info);
1827 r.r_info = TO_NATIVE(rela->r_info);
1828 r_sym = ELF_R_SYM(r.r_info);
1830 r.r_addend = TO_NATIVE(rela->r_addend);
1831 sym = elf->symtab_start + r_sym;
1832 /* Skip special sections */
1833 if (is_shndx_special(sym->st_shndx))
1835 if (is_second_extable_reloc(start, rela, fromsec))
1836 find_extable_entry_size(fromsec, &r);
1837 check_section_mismatch(modname, elf, &r, sym, fromsec);
1841 static void section_rel(const char *modname, struct elf_info *elf,
1848 const char *fromsec;
1850 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1851 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1853 fromsec = sech_name(elf, sechdr);
1854 fromsec += strlen(".rel");
1855 /* if from section (name) is know good then skip it */
1856 if (match(fromsec, section_white_list))
1859 for (rel = start; rel < stop; rel++) {
1860 r.r_offset = TO_NATIVE(rel->r_offset);
1861 #if KERNEL_ELFCLASS == ELFCLASS64
1862 if (elf->hdr->e_machine == EM_MIPS) {
1864 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1865 r_sym = TO_NATIVE(r_sym);
1866 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1867 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1869 r.r_info = TO_NATIVE(rel->r_info);
1870 r_sym = ELF_R_SYM(r.r_info);
1873 r.r_info = TO_NATIVE(rel->r_info);
1874 r_sym = ELF_R_SYM(r.r_info);
1877 switch (elf->hdr->e_machine) {
1879 if (addend_386_rel(elf, sechdr, &r))
1883 if (addend_arm_rel(elf, sechdr, &r))
1887 if (addend_mips_rel(elf, sechdr, &r))
1891 sym = elf->symtab_start + r_sym;
1892 /* Skip special sections */
1893 if (is_shndx_special(sym->st_shndx))
1895 if (is_second_extable_reloc(start, rel, fromsec))
1896 find_extable_entry_size(fromsec, &r);
1897 check_section_mismatch(modname, elf, &r, sym, fromsec);
1902 * A module includes a number of sections that are discarded
1903 * either when loaded or when used as built-in.
1904 * For loaded modules all functions marked __init and all data
1905 * marked __initdata will be discarded when the module has been initialized.
1906 * Likewise for modules used built-in the sections marked __exit
1907 * are discarded because __exit marked function are supposed to be called
1908 * only when a module is unloaded which never happens for built-in modules.
1909 * The check_sec_ref() function traverses all relocation records
1910 * to find all references to a section that reference a section that will
1911 * be discarded and warns about it.
1913 static void check_sec_ref(struct module *mod, const char *modname,
1914 struct elf_info *elf)
1917 Elf_Shdr *sechdrs = elf->sechdrs;
1919 /* Walk through all sections */
1920 for (i = 0; i < elf->num_sections; i++) {
1921 check_section(modname, elf, &elf->sechdrs[i]);
1922 /* We want to process only relocation sections and not .init */
1923 if (sechdrs[i].sh_type == SHT_RELA)
1924 section_rela(modname, elf, &elf->sechdrs[i]);
1925 else if (sechdrs[i].sh_type == SHT_REL)
1926 section_rel(modname, elf, &elf->sechdrs[i]);
1930 static char *remove_dot(char *s)
1932 size_t n = strcspn(s, ".");
1935 size_t m = strspn(s + n + 1, "0123456789");
1936 if (m && (s[n + m] == '.' || s[n + m] == 0))
1942 static void read_symbols(char *modname)
1944 const char *symname;
1948 struct elf_info info = { };
1951 if (!parse_elf(&info, modname))
1954 mod = new_module(modname);
1956 /* When there's no vmlinux, don't print warnings about
1957 * unresolved symbols (since there'll be too many ;) */
1958 if (is_vmlinux(modname)) {
1963 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1964 if (info.modinfo && !license && !is_vmlinux(modname))
1965 warn("modpost: missing MODULE_LICENSE() in %s\n"
1966 "see include/linux/module.h for "
1967 "more information\n", modname);
1969 if (license_is_gpl_compatible(license))
1970 mod->gpl_compatible = 1;
1972 mod->gpl_compatible = 0;
1975 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1976 "license", license);
1979 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1980 symname = remove_dot(info.strtab + sym->st_name);
1982 handle_modversions(mod, &info, sym, symname);
1983 handle_moddevtable(mod, &info, sym, symname);
1985 if (!is_vmlinux(modname) ||
1986 (is_vmlinux(modname) && vmlinux_section_warnings))
1987 check_sec_ref(mod, modname, &info);
1989 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1991 maybe_frob_rcs_version(modname, version, info.modinfo,
1992 version - (char *)info.hdr);
1993 if (version || (all_versions && !is_vmlinux(modname)))
1994 get_src_version(modname, mod->srcversion,
1995 sizeof(mod->srcversion)-1);
1997 parse_elf_finish(&info);
1999 /* Our trick to get versioning for module struct etc. - it's
2000 * never passed as an argument to an exported function, so
2001 * the automatic versioning doesn't pick it up, but it's really
2002 * important anyhow */
2004 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2007 static void read_symbols_from_files(const char *filename)
2010 char fname[PATH_MAX];
2012 if (strcmp(filename, "-") != 0) {
2013 in = fopen(filename, "r");
2015 fatal("Can't open filenames file %s: %m", filename);
2018 while (fgets(fname, PATH_MAX, in) != NULL) {
2019 if (strends(fname, "\n"))
2020 fname[strlen(fname)-1] = '\0';
2021 read_symbols(fname);
2030 /* We first write the generated file into memory using the
2031 * following helper, then compare to the file on disk and
2032 * only update the later if anything changed */
2034 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2035 const char *fmt, ...)
2042 len = vsnprintf(tmp, SZ, fmt, ap);
2043 buf_write(buf, tmp, len);
2047 void buf_write(struct buffer *buf, const char *s, int len)
2049 if (buf->size - buf->pos < len) {
2050 buf->size += len + SZ;
2051 buf->p = realloc(buf->p, buf->size);
2053 strncpy(buf->p + buf->pos, s, len);
2057 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2059 const char *e = is_vmlinux(m) ?"":".ko";
2063 fatal("modpost: GPL-incompatible module %s%s "
2064 "uses GPL-only symbol '%s'\n", m, e, s);
2066 case export_unused_gpl:
2067 fatal("modpost: GPL-incompatible module %s%s "
2068 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2070 case export_gpl_future:
2071 warn("modpost: GPL-incompatible module %s%s "
2072 "uses future GPL-only symbol '%s'\n", m, e, s);
2076 case export_unknown:
2082 static void check_for_unused(enum export exp, const char *m, const char *s)
2084 const char *e = is_vmlinux(m) ?"":".ko";
2088 case export_unused_gpl:
2089 warn("modpost: module %s%s "
2090 "uses symbol '%s' marked UNUSED\n", m, e, s);
2098 static void check_exports(struct module *mod)
2100 struct symbol *s, *exp;
2102 for (s = mod->unres; s; s = s->next) {
2103 const char *basename;
2104 exp = find_symbol(s->name);
2105 if (!exp || exp->module == mod)
2107 basename = strrchr(mod->name, '/');
2111 basename = mod->name;
2112 if (!mod->gpl_compatible)
2113 check_for_gpl_usage(exp->export, basename, exp->name);
2114 check_for_unused(exp->export, basename, exp->name);
2119 * Header for the generated file
2121 static void add_header(struct buffer *b, struct module *mod)
2123 buf_printf(b, "#include <linux/module.h>\n");
2124 buf_printf(b, "#include <linux/vermagic.h>\n");
2125 buf_printf(b, "#include <linux/compiler.h>\n");
2126 buf_printf(b, "\n");
2127 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2128 buf_printf(b, "\n");
2129 buf_printf(b, "__visible struct module __this_module\n");
2130 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2131 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2133 buf_printf(b, "\t.init = init_module,\n");
2134 if (mod->has_cleanup)
2135 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2136 "\t.exit = cleanup_module,\n"
2138 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2139 buf_printf(b, "};\n");
2142 static void add_intree_flag(struct buffer *b, int is_intree)
2145 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2148 static void add_staging_flag(struct buffer *b, const char *name)
2150 static const char *staging_dir = "drivers/staging";
2152 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2153 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2156 /* In kernel, this size is defined in linux/module.h;
2157 * here we use Elf_Addr instead of long for covering cross-compile
2159 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2162 * Record CRCs for unresolved symbols
2164 static int add_versions(struct buffer *b, struct module *mod)
2166 struct symbol *s, *exp;
2169 for (s = mod->unres; s; s = s->next) {
2170 exp = find_symbol(s->name);
2171 if (!exp || exp->module == mod) {
2172 if (have_vmlinux && !s->weak) {
2173 if (warn_unresolved) {
2174 warn("\"%s\" [%s.ko] undefined!\n",
2175 s->name, mod->name);
2177 merror("\"%s\" [%s.ko] undefined!\n",
2178 s->name, mod->name);
2184 s->module = exp->module;
2185 s->crc_valid = exp->crc_valid;
2192 buf_printf(b, "\n");
2193 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2194 buf_printf(b, "__used\n");
2195 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2197 for (s = mod->unres; s; s = s->next) {
2200 if (!s->crc_valid) {
2201 warn("\"%s\" [%s.ko] has no CRC!\n",
2202 s->name, mod->name);
2205 if (strlen(s->name) >= MODULE_NAME_LEN) {
2206 merror("too long symbol \"%s\" [%s.ko]\n",
2207 s->name, mod->name);
2211 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2215 buf_printf(b, "};\n");
2220 static void add_depends(struct buffer *b, struct module *mod,
2221 struct module *modules)
2227 for (m = modules; m; m = m->next)
2228 m->seen = is_vmlinux(m->name);
2230 buf_printf(b, "\n");
2231 buf_printf(b, "static const char __module_depends[]\n");
2232 buf_printf(b, "__used\n");
2233 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2234 buf_printf(b, "\"depends=");
2235 for (s = mod->unres; s; s = s->next) {
2240 if (s->module->seen)
2243 s->module->seen = 1;
2244 p = strrchr(s->module->name, '/');
2248 p = s->module->name;
2249 buf_printf(b, "%s%s", first ? "" : ",", p);
2252 buf_printf(b, "\";\n");
2255 static void add_srcversion(struct buffer *b, struct module *mod)
2257 if (mod->srcversion[0]) {
2258 buf_printf(b, "\n");
2259 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2264 static void write_if_changed(struct buffer *b, const char *fname)
2270 file = fopen(fname, "r");
2274 if (fstat(fileno(file), &st) < 0)
2277 if (st.st_size != b->pos)
2280 tmp = NOFAIL(malloc(b->pos));
2281 if (fread(tmp, 1, b->pos, file) != b->pos)
2284 if (memcmp(tmp, b->p, b->pos) != 0)
2296 file = fopen(fname, "w");
2301 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2308 /* parse Module.symvers file. line format:
2309 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2311 static void read_dump(const char *fname, unsigned int kernel)
2313 unsigned long size, pos = 0;
2314 void *file = grab_file(fname, &size);
2318 /* No symbol versions, silently ignore */
2321 while ((line = get_next_line(&pos, file, size))) {
2322 char *symname, *modname, *d, *export, *end;
2327 if (!(symname = strchr(line, '\t')))
2330 if (!(modname = strchr(symname, '\t')))
2333 if ((export = strchr(modname, '\t')) != NULL)
2335 if (export && ((end = strchr(export, '\t')) != NULL))
2337 crc = strtoul(line, &d, 16);
2338 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2340 mod = find_module(modname);
2342 if (is_vmlinux(modname))
2344 mod = new_module(modname);
2347 s = sym_add_exported(symname, mod, export_no(export));
2350 sym_update_crc(symname, mod, crc, export_no(export));
2352 release_file(file, size);
2355 release_file(file, size);
2356 fatal("parse error in symbol dump file\n");
2359 /* For normal builds always dump all symbols.
2360 * For external modules only dump symbols
2361 * that are not read from kernel Module.symvers.
2363 static int dump_sym(struct symbol *sym)
2365 if (!external_module)
2367 if (sym->vmlinux || sym->kernel)
2372 static void write_dump(const char *fname)
2374 struct buffer buf = { };
2375 struct symbol *symbol;
2378 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2379 symbol = symbolhash[n];
2381 if (dump_sym(symbol))
2382 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2383 symbol->crc, symbol->name,
2384 symbol->module->name,
2385 export_str(symbol->export));
2386 symbol = symbol->next;
2389 write_if_changed(&buf, fname);
2393 struct ext_sym_list {
2394 struct ext_sym_list *next;
2398 int main(int argc, char **argv)
2401 struct buffer buf = { };
2402 char *kernel_read = NULL, *module_read = NULL;
2403 char *dump_write = NULL, *files_source = NULL;
2406 struct ext_sym_list *extsym_iter;
2407 struct ext_sym_list *extsym_start = NULL;
2409 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2412 kernel_read = optarg;
2415 module_read = optarg;
2416 external_module = 1;
2419 external_module = 1;
2421 NOFAIL(malloc(sizeof(*extsym_iter)));
2422 extsym_iter->next = extsym_start;
2423 extsym_iter->file = optarg;
2424 extsym_start = extsym_iter;
2430 ignore_missing_files = 1;
2433 dump_write = optarg;
2439 vmlinux_section_warnings = 0;
2442 sec_mismatch_verbose = 0;
2445 files_source = optarg;
2448 warn_unresolved = 1;
2451 sec_mismatch_fatal = 1;
2459 read_dump(kernel_read, 1);
2461 read_dump(module_read, 0);
2462 while (extsym_start) {
2463 read_dump(extsym_start->file, 0);
2464 extsym_iter = extsym_start->next;
2466 extsym_start = extsym_iter;
2469 while (optind < argc)
2470 read_symbols(argv[optind++]);
2473 read_symbols_from_files(files_source);
2475 for (mod = modules; mod; mod = mod->next) {
2483 for (mod = modules; mod; mod = mod->next) {
2484 char fname[PATH_MAX];
2491 add_header(&buf, mod);
2492 add_intree_flag(&buf, !external_module);
2493 add_staging_flag(&buf, mod->name);
2494 err |= add_versions(&buf, mod);
2495 add_depends(&buf, mod, modules);
2496 add_moddevtable(&buf, mod);
2497 add_srcversion(&buf, mod);
2499 sprintf(fname, "%s.mod.c", mod->name);
2500 write_if_changed(&buf, fname);
2503 write_dump(dump_write);
2504 if (sec_mismatch_count) {
2505 if (!sec_mismatch_verbose) {
2506 warn("modpost: Found %d section mismatch(es).\n"
2507 "To see full details build your kernel with:\n"
2508 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2509 sec_mismatch_count);
2511 if (sec_mismatch_fatal) {
2512 fatal("modpost: Section mismatches detected.\n"
2513 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");