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)
613 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
614 strncmp(symname, "__ksymtab", 9) == 0)
615 export = export_from_secname(info, get_secindex(info, sym));
617 export = export_from_sec(info, get_secindex(info, sym));
620 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
621 crc = (unsigned int) sym->st_value;
622 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
626 switch (sym->st_shndx) {
628 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
629 /* Should warn here, but modpost runs before the linker */
631 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
634 /* undefined symbol */
635 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
636 ELF_ST_BIND(sym->st_info) != STB_WEAK)
638 if (ignore_undef_symbol(info, symname))
640 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
641 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
642 /* add compatibility with older glibc */
643 #ifndef STT_SPARC_REGISTER
644 #define STT_SPARC_REGISTER STT_REGISTER
646 if (info->hdr->e_machine == EM_SPARC ||
647 info->hdr->e_machine == EM_SPARCV9) {
648 /* Ignore register directives. */
649 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
651 if (symname[0] == '.') {
652 char *munged = NOFAIL(strdup(symname));
654 munged[1] = toupper(munged[1]);
660 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
661 if (symname[0] != '_')
666 mod->unres = alloc_symbol(symname,
667 ELF_ST_BIND(sym->st_info) == STB_WEAK,
671 /* All exported symbols */
672 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
673 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
676 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
678 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
679 mod->has_cleanup = 1;
685 * Parse tag=value strings from .modinfo section
687 static char *next_string(char *string, unsigned long *secsize)
689 /* Skip non-zero chars */
692 if ((*secsize)-- <= 1)
696 /* Skip any zero padding. */
699 if ((*secsize)-- <= 1)
705 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
706 const char *tag, char *info)
709 unsigned int taglen = strlen(tag);
710 unsigned long size = modinfo_len;
713 size -= info - (char *)modinfo;
714 modinfo = next_string(info, &size);
717 for (p = modinfo; p; p = next_string(p, &size)) {
718 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
719 return p + taglen + 1;
724 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
728 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
732 * Test if string s ends in string sub
735 static int strrcmp(const char *s, const char *sub)
743 sublen = strlen(sub);
745 if ((slen == 0) || (sublen == 0))
751 return memcmp(s + slen - sublen, sub, sublen);
754 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
757 return elf->strtab + sym->st_name;
762 static const char *sec_name(struct elf_info *elf, int secindex)
764 Elf_Shdr *sechdrs = elf->sechdrs;
765 return (void *)elf->hdr +
766 elf->sechdrs[elf->secindex_strings].sh_offset +
767 sechdrs[secindex].sh_name;
770 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
772 return (void *)elf->hdr +
773 elf->sechdrs[elf->secindex_strings].sh_offset +
777 /* The pattern is an array of simple patterns.
778 * "foo" will match an exact string equal to "foo"
779 * "*foo" will match a string that ends with "foo"
780 * "foo*" will match a string that begins with "foo"
781 * "*foo*" will match a string that contains "foo"
783 static int match(const char *sym, const char * const pat[])
788 const char *endp = p + strlen(p) - 1;
791 if (*p == '*' && *endp == '*') {
792 char *here, *bare = strndup(p + 1, strlen(p) - 2);
794 here = strstr(sym, bare);
800 else if (*p == '*') {
801 if (strrcmp(sym, p + 1) == 0)
805 else if (*endp == '*') {
806 if (strncmp(sym, p, strlen(p) - 1) == 0)
811 if (strcmp(p, sym) == 0)
819 /* sections that we do not want to do full section mismatch check on */
820 static const char *const section_white_list[] =
824 ".cranges", /* sh64 */
825 ".zdebug*", /* Compressed debug sections. */
826 ".GCC-command-line", /* mn10300 */
827 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
828 ".mdebug*", /* alpha, score, mips etc. */
829 ".pdr", /* alpha, score, mips etc. */
834 ".xt.prop", /* xtensa */
835 ".xt.lit", /* xtensa */
836 ".arcextmap*", /* arc */
837 ".gnu.linkonce.arcext*", /* arc : modules */
838 ".cmem*", /* EZchip */
839 ".fmt_slot*", /* EZchip */
846 * This is used to find sections missing the SHF_ALLOC flag.
847 * The cause of this is often a section specified in assembler
848 * without "ax" / "aw".
850 static void check_section(const char *modname, struct elf_info *elf,
853 const char *sec = sech_name(elf, sechdr);
855 if (sechdr->sh_type == SHT_PROGBITS &&
856 !(sechdr->sh_flags & SHF_ALLOC) &&
857 !match(sec, section_white_list)) {
858 warn("%s (%s): unexpected non-allocatable section.\n"
859 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
860 "Note that for example <linux/init.h> contains\n"
861 "section definitions for use in .S files.\n\n",
868 #define ALL_INIT_DATA_SECTIONS \
869 ".init.setup", ".init.rodata", ".meminit.rodata", \
870 ".init.data", ".meminit.data"
871 #define ALL_EXIT_DATA_SECTIONS \
872 ".exit.data", ".memexit.data"
874 #define ALL_INIT_TEXT_SECTIONS \
875 ".init.text", ".meminit.text"
876 #define ALL_EXIT_TEXT_SECTIONS \
877 ".exit.text", ".memexit.text"
879 #define ALL_PCI_INIT_SECTIONS \
880 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
881 ".pci_fixup_enable", ".pci_fixup_resume", \
882 ".pci_fixup_resume_early", ".pci_fixup_suspend"
884 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
885 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
887 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
888 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
890 #define DATA_SECTIONS ".data", ".data.rel"
891 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
892 ".kprobes.text", ".cpuidle.text"
893 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
894 ".fixup", ".entry.text", ".exception.text", ".text.*", \
897 #define INIT_SECTIONS ".init.*"
898 #define MEM_INIT_SECTIONS ".meminit.*"
900 #define EXIT_SECTIONS ".exit.*"
901 #define MEM_EXIT_SECTIONS ".memexit.*"
903 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
904 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
906 /* init data sections */
907 static const char *const init_data_sections[] =
908 { ALL_INIT_DATA_SECTIONS, NULL };
910 /* all init sections */
911 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
913 /* All init and exit sections (code + data) */
914 static const char *const init_exit_sections[] =
915 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
917 /* all text sections */
918 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
921 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
924 /* symbols in .data that may refer to init/exit sections */
925 #define DEFAULT_SYMBOL_WHITE_LIST \
927 "*_template", /* scsi uses *_template a lot */ \
928 "*_timer", /* arm uses ops structures named _timer a lot */ \
929 "*_sht", /* scsi also used *_sht to some extent */ \
935 static const char *const head_sections[] = { ".head.text*", NULL };
936 static const char *const linker_symbols[] =
937 { "__init_begin", "_sinittext", "_einittext", NULL };
938 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
945 XXXINIT_TO_SOME_INIT,
946 XXXEXIT_TO_SOME_EXIT,
947 ANY_INIT_TO_ANY_EXIT,
948 ANY_EXIT_TO_ANY_INIT,
954 * Describe how to match sections on different criterias:
956 * @fromsec: Array of sections to be matched.
958 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
959 * this array is forbidden (black-list). Can be empty.
961 * @good_tosec: Relocations applied to a section in @fromsec must be
962 * targetting sections in this array (white-list). Can be empty.
964 * @mismatch: Type of mismatch.
966 * @symbol_white_list: Do not match a relocation to a symbol in this list
967 * even if it is targetting a section in @bad_to_sec.
969 * @handler: Specific handler to call when a match is found. If NULL,
970 * default_mismatch_handler() will be called.
973 struct sectioncheck {
974 const char *fromsec[20];
975 const char *bad_tosec[20];
976 const char *good_tosec[20];
977 enum mismatch mismatch;
978 const char *symbol_white_list[20];
979 void (*handler)(const char *modname, struct elf_info *elf,
980 const struct sectioncheck* const mismatch,
981 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
985 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
986 const struct sectioncheck* const mismatch,
987 Elf_Rela *r, Elf_Sym *sym,
988 const char *fromsec);
990 static const struct sectioncheck sectioncheck[] = {
991 /* Do not reference init/exit code/data from
992 * normal code and data
995 .fromsec = { TEXT_SECTIONS, NULL },
996 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
997 .mismatch = TEXT_TO_ANY_INIT,
998 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1001 .fromsec = { DATA_SECTIONS, NULL },
1002 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1003 .mismatch = DATA_TO_ANY_INIT,
1004 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1007 .fromsec = { DATA_SECTIONS, NULL },
1008 .bad_tosec = { INIT_SECTIONS, NULL },
1009 .mismatch = DATA_TO_ANY_INIT,
1010 .symbol_white_list = {
1011 "*_template", "*_timer", "*_sht", "*_ops",
1012 "*_probe", "*_probe_one", "*_console", NULL
1016 .fromsec = { TEXT_SECTIONS, NULL },
1017 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1018 .mismatch = TEXT_TO_ANY_EXIT,
1019 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1022 .fromsec = { DATA_SECTIONS, NULL },
1023 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1024 .mismatch = DATA_TO_ANY_EXIT,
1025 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1027 /* Do not reference init code/data from meminit code/data */
1029 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1030 .bad_tosec = { INIT_SECTIONS, NULL },
1031 .mismatch = XXXINIT_TO_SOME_INIT,
1032 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1034 /* Do not reference exit code/data from memexit code/data */
1036 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1037 .bad_tosec = { EXIT_SECTIONS, NULL },
1038 .mismatch = XXXEXIT_TO_SOME_EXIT,
1039 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1041 /* Do not use exit code/data from init code */
1043 .fromsec = { ALL_INIT_SECTIONS, NULL },
1044 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1045 .mismatch = ANY_INIT_TO_ANY_EXIT,
1046 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1048 /* Do not use init code/data from exit code */
1050 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1051 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1052 .mismatch = ANY_EXIT_TO_ANY_INIT,
1053 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1056 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1057 .bad_tosec = { INIT_SECTIONS, NULL },
1058 .mismatch = ANY_INIT_TO_ANY_EXIT,
1059 .symbol_white_list = { NULL },
1061 /* Do not export init/exit functions or data */
1063 .fromsec = { "__ksymtab*", NULL },
1064 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1065 .mismatch = EXPORT_TO_INIT_EXIT,
1066 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1069 .fromsec = { "__ex_table", NULL },
1070 /* If you're adding any new black-listed sections in here, consider
1071 * adding a special 'printer' for them in scripts/check_extable.
1073 .bad_tosec = { ".altinstr_replacement", NULL },
1074 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1075 .mismatch = EXTABLE_TO_NON_TEXT,
1076 .handler = extable_mismatch_handler,
1080 static const struct sectioncheck *section_mismatch(
1081 const char *fromsec, const char *tosec)
1084 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1085 const struct sectioncheck *check = §ioncheck[0];
1088 * The target section could be the SHT_NUL section when we're
1089 * handling relocations to un-resolved symbols, trying to match it
1090 * doesn't make much sense and causes build failures on parisc and
1091 * mn10300 architectures.
1096 for (i = 0; i < elems; i++) {
1097 if (match(fromsec, check->fromsec)) {
1098 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1100 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1109 * Whitelist to allow certain references to pass with no warning.
1112 * If a module parameter is declared __initdata and permissions=0
1113 * then this is legal despite the warning generated.
1114 * We cannot see value of permissions here, so just ignore
1116 * The pattern is identified by:
1117 * tosec = .init.data
1122 * module_param_call() ops can refer to __init set function if permissions=0
1123 * The pattern is identified by:
1124 * tosec = .init.text
1126 * atsym = __param_ops_*
1129 * Many drivers utilise a *driver container with references to
1130 * add, remove, probe functions etc.
1131 * the pattern is identified by:
1132 * tosec = init or exit section
1133 * fromsec = data section
1134 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1135 * *probe_one, *_console, *_timer
1138 * Whitelist all references from .head.text to any init section
1141 * Some symbols belong to init section but still it is ok to reference
1142 * these from non-init sections as these symbols don't have any memory
1143 * allocated for them and symbol address and value are same. So even
1144 * if init section is freed, its ok to reference those symbols.
1145 * For ex. symbols marking the init section boundaries.
1146 * This pattern is identified by
1147 * refsymname = __init_begin, _sinittext, _einittext
1150 * GCC may optimize static inlines when fed constant arg(s) resulting
1151 * in functions like cpumask_empty() -- generating an associated symbol
1152 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1153 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1154 * meaningless section warning. May need to add isra symbols too...
1155 * This pattern is identified by
1156 * tosec = init section
1157 * fromsec = text section
1158 * refsymname = *.constprop.*
1161 * Hide section mismatch warnings for ELF local symbols. The goal
1162 * is to eliminate false positive modpost warnings caused by
1163 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1164 * Autogenerated symbol names bypass modpost's "Pattern 2"
1165 * whitelisting, which relies on pattern-matching against symbol
1166 * names to work. (One situation where gcc can autogenerate ELF
1167 * local symbols is when "-fsection-anchors" is used.)
1169 static int secref_whitelist(const struct sectioncheck *mismatch,
1170 const char *fromsec, const char *fromsym,
1171 const char *tosec, const char *tosym)
1173 /* Check for pattern 1 */
1174 if (match(tosec, init_data_sections) &&
1175 match(fromsec, data_sections) &&
1176 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1179 /* Check for pattern 1a */
1180 if (strcmp(tosec, ".init.text") == 0 &&
1181 match(fromsec, data_sections) &&
1182 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1185 /* Check for pattern 2 */
1186 if (match(tosec, init_exit_sections) &&
1187 match(fromsec, data_sections) &&
1188 match(fromsym, mismatch->symbol_white_list))
1191 /* Check for pattern 3 */
1192 if (match(fromsec, head_sections) &&
1193 match(tosec, init_sections))
1196 /* Check for pattern 4 */
1197 if (match(tosym, linker_symbols))
1200 /* Check for pattern 5 */
1201 if (match(fromsec, text_sections) &&
1202 match(tosec, init_sections) &&
1203 match(fromsym, optim_symbols))
1206 /* Check for pattern 6 */
1207 if (strstarts(fromsym, ".L"))
1213 static inline int is_arm_mapping_symbol(const char *str)
1215 return str[0] == '$' && strchr("axtd", str[1])
1216 && (str[2] == '\0' || str[2] == '.');
1220 * If there's no name there, ignore it; likewise, ignore it if it's
1221 * one of the magic symbols emitted used by current ARM tools.
1223 * Otherwise if find_symbols_between() returns those symbols, they'll
1224 * fail the whitelist tests and cause lots of false alarms ... fixable
1225 * only by merging __exit and __init sections into __text, bloating
1226 * the kernel (which is especially evil on embedded platforms).
1228 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1230 const char *name = elf->strtab + sym->st_name;
1232 if (!name || !strlen(name))
1234 return !is_arm_mapping_symbol(name);
1238 * Find symbol based on relocation record info.
1239 * In some cases the symbol supplied is a valid symbol so
1240 * return refsym. If st_name != 0 we assume this is a valid symbol.
1241 * In other cases the symbol needs to be looked up in the symbol table
1242 * based on section and address.
1244 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1248 Elf_Sym *near = NULL;
1249 Elf64_Sword distance = 20;
1251 unsigned int relsym_secindex;
1253 if (relsym->st_name != 0)
1256 relsym_secindex = get_secindex(elf, relsym);
1257 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1258 if (get_secindex(elf, sym) != relsym_secindex)
1260 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1262 if (!is_valid_name(elf, sym))
1264 if (sym->st_value == addr)
1266 /* Find a symbol nearby - addr are maybe negative */
1267 d = sym->st_value - addr;
1269 d = addr - sym->st_value;
1275 /* We need a close match */
1283 * Find symbols before or equal addr and after addr - in the section sec.
1284 * If we find two symbols with equal offset prefer one with a valid name.
1285 * The ELF format may have a better way to detect what type of symbol
1286 * it is, but this works for now.
1288 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1292 Elf_Sym *near = NULL;
1293 Elf_Addr distance = ~0;
1295 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1298 if (is_shndx_special(sym->st_shndx))
1300 symsec = sec_name(elf, get_secindex(elf, sym));
1301 if (strcmp(symsec, sec) != 0)
1303 if (!is_valid_name(elf, sym))
1305 if (sym->st_value <= addr) {
1306 if ((addr - sym->st_value) < distance) {
1307 distance = addr - sym->st_value;
1309 } else if ((addr - sym->st_value) == distance) {
1318 * Convert a section name to the function/data attribute
1319 * .init.text => __init
1320 * .memexitconst => __memconst
1323 * The memory of returned value has been allocated on a heap. The user of this
1324 * method should free it after usage.
1326 static char *sec2annotation(const char *s)
1328 if (match(s, init_exit_sections)) {
1329 char *p = NOFAIL(malloc(20));
1336 while (*s && *s != '.')
1341 if (strstr(s, "rodata") != NULL)
1342 strcat(p, "const ");
1343 else if (strstr(s, "data") != NULL)
1349 return NOFAIL(strdup(""));
1353 static int is_function(Elf_Sym *sym)
1356 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1361 static void print_section_list(const char * const list[20])
1363 const char *const *s = list;
1366 fprintf(stderr, "%s", *s);
1369 fprintf(stderr, ", ");
1371 fprintf(stderr, "\n");
1374 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1377 case 0: *name = "variable"; *name_p = ""; break;
1378 case 1: *name = "function"; *name_p = "()"; break;
1379 default: *name = "(unknown reference)"; *name_p = ""; break;
1384 * Print a warning about a section mismatch.
1385 * Try to find symbols near it so user can find it.
1386 * Check whitelist before warning - it may be a false positive.
1388 static void report_sec_mismatch(const char *modname,
1389 const struct sectioncheck *mismatch,
1390 const char *fromsec,
1391 unsigned long long fromaddr,
1392 const char *fromsym,
1394 const char *tosec, const char *tosym,
1397 const char *from, *from_p;
1398 const char *to, *to_p;
1402 sec_mismatch_count++;
1403 if (!sec_mismatch_verbose)
1406 get_pretty_name(from_is_func, &from, &from_p);
1407 get_pretty_name(to_is_func, &to, &to_p);
1409 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1410 "to the %s %s:%s%s\n",
1411 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1414 switch (mismatch->mismatch) {
1415 case TEXT_TO_ANY_INIT:
1416 prl_from = sec2annotation(fromsec);
1417 prl_to = sec2annotation(tosec);
1419 "The function %s%s() references\n"
1421 "This is often because %s lacks a %s\n"
1422 "annotation or the annotation of %s is wrong.\n",
1424 to, prl_to, tosym, to_p,
1425 fromsym, prl_to, tosym);
1429 case DATA_TO_ANY_INIT: {
1430 prl_to = sec2annotation(tosec);
1432 "The variable %s references\n"
1434 "If the reference is valid then annotate the\n"
1435 "variable with __init* or __refdata (see linux/init.h) "
1436 "or name the variable:\n",
1437 fromsym, to, prl_to, tosym, to_p);
1438 print_section_list(mismatch->symbol_white_list);
1442 case TEXT_TO_ANY_EXIT:
1443 prl_to = sec2annotation(tosec);
1445 "The function %s() references a %s in an exit section.\n"
1446 "Often the %s %s%s has valid usage outside the exit section\n"
1447 "and the fix is to remove the %sannotation of %s.\n",
1448 fromsym, to, to, tosym, to_p, prl_to, tosym);
1451 case DATA_TO_ANY_EXIT: {
1452 prl_to = sec2annotation(tosec);
1454 "The variable %s references\n"
1456 "If the reference is valid then annotate the\n"
1457 "variable with __exit* (see linux/init.h) or "
1458 "name the variable:\n",
1459 fromsym, to, prl_to, tosym, to_p);
1460 print_section_list(mismatch->symbol_white_list);
1464 case XXXINIT_TO_SOME_INIT:
1465 case XXXEXIT_TO_SOME_EXIT:
1466 prl_from = sec2annotation(fromsec);
1467 prl_to = sec2annotation(tosec);
1469 "The %s %s%s%s references\n"
1471 "If %s is only used by %s then\n"
1472 "annotate %s with a matching annotation.\n",
1473 from, prl_from, fromsym, from_p,
1474 to, prl_to, tosym, to_p,
1475 tosym, fromsym, tosym);
1479 case ANY_INIT_TO_ANY_EXIT:
1480 prl_from = sec2annotation(fromsec);
1481 prl_to = sec2annotation(tosec);
1483 "The %s %s%s%s references\n"
1485 "This is often seen when error handling "
1486 "in the init function\n"
1487 "uses functionality in the exit path.\n"
1488 "The fix is often to remove the %sannotation of\n"
1489 "%s%s so it may be used outside an exit section.\n",
1490 from, prl_from, fromsym, from_p,
1491 to, prl_to, tosym, to_p,
1492 prl_to, tosym, to_p);
1496 case ANY_EXIT_TO_ANY_INIT:
1497 prl_from = sec2annotation(fromsec);
1498 prl_to = sec2annotation(tosec);
1500 "The %s %s%s%s references\n"
1502 "This is often seen when error handling "
1503 "in the exit function\n"
1504 "uses functionality in the init path.\n"
1505 "The fix is often to remove the %sannotation of\n"
1506 "%s%s so it may be used outside an init section.\n",
1507 from, prl_from, fromsym, from_p,
1508 to, prl_to, tosym, to_p,
1509 prl_to, tosym, to_p);
1513 case EXPORT_TO_INIT_EXIT:
1514 prl_to = sec2annotation(tosec);
1516 "The symbol %s is exported and annotated %s\n"
1517 "Fix this by removing the %sannotation of %s "
1518 "or drop the export.\n",
1519 tosym, prl_to, prl_to, tosym);
1522 case EXTABLE_TO_NON_TEXT:
1523 fatal("There's a special handler for this mismatch type, "
1524 "we should never get here.");
1527 fprintf(stderr, "\n");
1530 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1531 const struct sectioncheck* const mismatch,
1532 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1538 const char *fromsym;
1540 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1541 fromsym = sym_name(elf, from);
1543 if (!strncmp(fromsym, "reference___initcall",
1544 sizeof("reference___initcall")-1))
1547 tosec = sec_name(elf, get_secindex(elf, sym));
1548 to = find_elf_symbol(elf, r->r_addend, sym);
1549 tosym = sym_name(elf, to);
1551 /* check whitelist - we may ignore it */
1552 if (secref_whitelist(mismatch,
1553 fromsec, fromsym, tosec, tosym)) {
1554 report_sec_mismatch(modname, mismatch,
1555 fromsec, r->r_offset, fromsym,
1556 is_function(from), tosec, tosym,
1561 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1563 if (section_index > elf->num_sections)
1564 fatal("section_index is outside elf->num_sections!\n");
1566 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1570 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1571 * to know the sizeof(struct exception_table_entry) for the target architecture.
1573 static unsigned int extable_entry_size = 0;
1574 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1577 * If we're currently checking the second relocation within __ex_table,
1578 * that relocation offset tells us the offsetof(struct
1579 * exception_table_entry, fixup) which is equal to sizeof(struct
1580 * exception_table_entry) divided by two. We use that to our advantage
1581 * since there's no portable way to get that size as every architecture
1582 * seems to go with different sized types. Not pretty but better than
1583 * hard-coding the size for every architecture..
1585 if (!extable_entry_size)
1586 extable_entry_size = r->r_offset * 2;
1589 static inline bool is_extable_fault_address(Elf_Rela *r)
1592 * extable_entry_size is only discovered after we've handled the
1593 * _second_ relocation in __ex_table, so only abort when we're not
1594 * handling the first reloc and extable_entry_size is zero.
1596 if (r->r_offset && extable_entry_size == 0)
1597 fatal("extable_entry size hasn't been discovered!\n");
1599 return ((r->r_offset == 0) ||
1600 (r->r_offset % extable_entry_size == 0));
1603 #define is_second_extable_reloc(Start, Cur, Sec) \
1604 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1606 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1607 const struct sectioncheck* const mismatch,
1608 Elf_Rela* r, Elf_Sym* sym,
1609 const char* fromsec, const char* tosec)
1611 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1612 const char* fromsym_name = sym_name(elf, fromsym);
1613 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1614 const char* tosym_name = sym_name(elf, tosym);
1615 const char* from_pretty_name;
1616 const char* from_pretty_name_p;
1617 const char* to_pretty_name;
1618 const char* to_pretty_name_p;
1620 get_pretty_name(is_function(fromsym),
1621 &from_pretty_name, &from_pretty_name_p);
1622 get_pretty_name(is_function(tosym),
1623 &to_pretty_name, &to_pretty_name_p);
1625 warn("%s(%s+0x%lx): Section mismatch in reference"
1626 " from the %s %s%s to the %s %s:%s%s\n",
1627 modname, fromsec, (long)r->r_offset, from_pretty_name,
1628 fromsym_name, from_pretty_name_p,
1629 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1631 if (!match(tosec, mismatch->bad_tosec) &&
1632 is_executable_section(elf, get_secindex(elf, sym)))
1634 "The relocation at %s+0x%lx references\n"
1635 "section \"%s\" which is not in the list of\n"
1636 "authorized sections. If you're adding a new section\n"
1637 "and/or if this reference is valid, add \"%s\" to the\n"
1638 "list of authorized sections to jump to on fault.\n"
1639 "This can be achieved by adding \"%s\" to \n"
1640 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1641 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1644 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1645 const struct sectioncheck* const mismatch,
1646 Elf_Rela* r, Elf_Sym* sym,
1647 const char *fromsec)
1649 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1651 sec_mismatch_count++;
1653 if (sec_mismatch_verbose)
1654 report_extable_warnings(modname, elf, mismatch, r, sym,
1657 if (match(tosec, mismatch->bad_tosec))
1658 fatal("The relocation at %s+0x%lx references\n"
1659 "section \"%s\" which is black-listed.\n"
1660 "Something is seriously wrong and should be fixed.\n"
1661 "You might get more information about where this is\n"
1662 "coming from by using scripts/check_extable.sh %s\n",
1663 fromsec, (long)r->r_offset, tosec, modname);
1664 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1665 if (is_extable_fault_address(r))
1666 fatal("The relocation at %s+0x%lx references\n"
1667 "section \"%s\" which is not executable, IOW\n"
1668 "it is not possible for the kernel to fault\n"
1669 "at that address. Something is seriously wrong\n"
1670 "and should be fixed.\n",
1671 fromsec, (long)r->r_offset, tosec);
1673 fatal("The relocation at %s+0x%lx references\n"
1674 "section \"%s\" which is not executable, IOW\n"
1675 "the kernel will fault if it ever tries to\n"
1676 "jump to it. Something is seriously wrong\n"
1677 "and should be fixed.\n",
1678 fromsec, (long)r->r_offset, tosec);
1682 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1683 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1685 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1686 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1689 if (mismatch->handler)
1690 mismatch->handler(modname, elf, mismatch,
1693 default_mismatch_handler(modname, elf, mismatch,
1698 static unsigned int *reloc_location(struct elf_info *elf,
1699 Elf_Shdr *sechdr, Elf_Rela *r)
1701 Elf_Shdr *sechdrs = elf->sechdrs;
1702 int section = sechdr->sh_info;
1704 return (void *)elf->hdr + sechdrs[section].sh_offset +
1708 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1710 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1711 unsigned int *location = reloc_location(elf, sechdr, r);
1715 r->r_addend = TO_NATIVE(*location);
1718 r->r_addend = TO_NATIVE(*location) + 4;
1719 /* For CONFIG_RELOCATABLE=y */
1720 if (elf->hdr->e_type == ET_EXEC)
1721 r->r_addend += r->r_offset;
1728 #define R_ARM_CALL 28
1730 #ifndef R_ARM_JUMP24
1731 #define R_ARM_JUMP24 29
1734 #ifndef R_ARM_THM_CALL
1735 #define R_ARM_THM_CALL 10
1737 #ifndef R_ARM_THM_JUMP24
1738 #define R_ARM_THM_JUMP24 30
1740 #ifndef R_ARM_THM_JUMP19
1741 #define R_ARM_THM_JUMP19 51
1744 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1746 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1750 /* From ARM ABI: (S + A) | T */
1751 r->r_addend = (int)(long)
1752 (elf->symtab_start + ELF_R_SYM(r->r_info));
1757 case R_ARM_THM_CALL:
1758 case R_ARM_THM_JUMP24:
1759 case R_ARM_THM_JUMP19:
1760 /* From ARM ABI: ((S + A) | T) - P */
1761 r->r_addend = (int)(long)(elf->hdr +
1763 (r->r_offset - sechdr->sh_addr));
1771 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1773 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1774 unsigned int *location = reloc_location(elf, sechdr, r);
1777 if (r_typ == R_MIPS_HI16)
1778 return 1; /* skip this */
1779 inst = TO_NATIVE(*location);
1782 r->r_addend = inst & 0xffff;
1785 r->r_addend = (inst & 0x03ffffff) << 2;
1794 static void section_rela(const char *modname, struct elf_info *elf,
1801 const char *fromsec;
1803 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1804 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1806 fromsec = sech_name(elf, sechdr);
1807 fromsec += strlen(".rela");
1808 /* if from section (name) is know good then skip it */
1809 if (match(fromsec, section_white_list))
1812 for (rela = start; rela < stop; rela++) {
1813 r.r_offset = TO_NATIVE(rela->r_offset);
1814 #if KERNEL_ELFCLASS == ELFCLASS64
1815 if (elf->hdr->e_machine == EM_MIPS) {
1817 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1818 r_sym = TO_NATIVE(r_sym);
1819 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1820 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1822 r.r_info = TO_NATIVE(rela->r_info);
1823 r_sym = ELF_R_SYM(r.r_info);
1826 r.r_info = TO_NATIVE(rela->r_info);
1827 r_sym = ELF_R_SYM(r.r_info);
1829 r.r_addend = TO_NATIVE(rela->r_addend);
1830 sym = elf->symtab_start + r_sym;
1831 /* Skip special sections */
1832 if (is_shndx_special(sym->st_shndx))
1834 if (is_second_extable_reloc(start, rela, fromsec))
1835 find_extable_entry_size(fromsec, &r);
1836 check_section_mismatch(modname, elf, &r, sym, fromsec);
1840 static void section_rel(const char *modname, struct elf_info *elf,
1847 const char *fromsec;
1849 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1850 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1852 fromsec = sech_name(elf, sechdr);
1853 fromsec += strlen(".rel");
1854 /* if from section (name) is know good then skip it */
1855 if (match(fromsec, section_white_list))
1858 for (rel = start; rel < stop; rel++) {
1859 r.r_offset = TO_NATIVE(rel->r_offset);
1860 #if KERNEL_ELFCLASS == ELFCLASS64
1861 if (elf->hdr->e_machine == EM_MIPS) {
1863 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1864 r_sym = TO_NATIVE(r_sym);
1865 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1866 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1868 r.r_info = TO_NATIVE(rel->r_info);
1869 r_sym = ELF_R_SYM(r.r_info);
1872 r.r_info = TO_NATIVE(rel->r_info);
1873 r_sym = ELF_R_SYM(r.r_info);
1876 switch (elf->hdr->e_machine) {
1878 if (addend_386_rel(elf, sechdr, &r))
1882 if (addend_arm_rel(elf, sechdr, &r))
1886 if (addend_mips_rel(elf, sechdr, &r))
1890 sym = elf->symtab_start + r_sym;
1891 /* Skip special sections */
1892 if (is_shndx_special(sym->st_shndx))
1894 if (is_second_extable_reloc(start, rel, fromsec))
1895 find_extable_entry_size(fromsec, &r);
1896 check_section_mismatch(modname, elf, &r, sym, fromsec);
1901 * A module includes a number of sections that are discarded
1902 * either when loaded or when used as built-in.
1903 * For loaded modules all functions marked __init and all data
1904 * marked __initdata will be discarded when the module has been initialized.
1905 * Likewise for modules used built-in the sections marked __exit
1906 * are discarded because __exit marked function are supposed to be called
1907 * only when a module is unloaded which never happens for built-in modules.
1908 * The check_sec_ref() function traverses all relocation records
1909 * to find all references to a section that reference a section that will
1910 * be discarded and warns about it.
1912 static void check_sec_ref(struct module *mod, const char *modname,
1913 struct elf_info *elf)
1916 Elf_Shdr *sechdrs = elf->sechdrs;
1918 /* Walk through all sections */
1919 for (i = 0; i < elf->num_sections; i++) {
1920 check_section(modname, elf, &elf->sechdrs[i]);
1921 /* We want to process only relocation sections and not .init */
1922 if (sechdrs[i].sh_type == SHT_RELA)
1923 section_rela(modname, elf, &elf->sechdrs[i]);
1924 else if (sechdrs[i].sh_type == SHT_REL)
1925 section_rel(modname, elf, &elf->sechdrs[i]);
1929 static char *remove_dot(char *s)
1931 size_t n = strcspn(s, ".");
1934 size_t m = strspn(s + n + 1, "0123456789");
1935 if (m && (s[n + m] == '.' || s[n + m] == 0))
1941 static void read_symbols(char *modname)
1943 const char *symname;
1947 struct elf_info info = { };
1950 if (!parse_elf(&info, modname))
1953 mod = new_module(modname);
1955 /* When there's no vmlinux, don't print warnings about
1956 * unresolved symbols (since there'll be too many ;) */
1957 if (is_vmlinux(modname)) {
1962 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1963 if (info.modinfo && !license && !is_vmlinux(modname))
1964 warn("modpost: missing MODULE_LICENSE() in %s\n"
1965 "see include/linux/module.h for "
1966 "more information\n", modname);
1968 if (license_is_gpl_compatible(license))
1969 mod->gpl_compatible = 1;
1971 mod->gpl_compatible = 0;
1974 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1975 "license", license);
1978 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1979 symname = remove_dot(info.strtab + sym->st_name);
1981 handle_modversions(mod, &info, sym, symname);
1982 handle_moddevtable(mod, &info, sym, symname);
1984 if (!is_vmlinux(modname) ||
1985 (is_vmlinux(modname) && vmlinux_section_warnings))
1986 check_sec_ref(mod, modname, &info);
1988 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1990 maybe_frob_rcs_version(modname, version, info.modinfo,
1991 version - (char *)info.hdr);
1992 if (version || (all_versions && !is_vmlinux(modname)))
1993 get_src_version(modname, mod->srcversion,
1994 sizeof(mod->srcversion)-1);
1996 parse_elf_finish(&info);
1998 /* Our trick to get versioning for module struct etc. - it's
1999 * never passed as an argument to an exported function, so
2000 * the automatic versioning doesn't pick it up, but it's really
2001 * important anyhow */
2003 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2006 static void read_symbols_from_files(const char *filename)
2009 char fname[PATH_MAX];
2011 if (strcmp(filename, "-") != 0) {
2012 in = fopen(filename, "r");
2014 fatal("Can't open filenames file %s: %m", filename);
2017 while (fgets(fname, PATH_MAX, in) != NULL) {
2018 if (strends(fname, "\n"))
2019 fname[strlen(fname)-1] = '\0';
2020 read_symbols(fname);
2029 /* We first write the generated file into memory using the
2030 * following helper, then compare to the file on disk and
2031 * only update the later if anything changed */
2033 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2034 const char *fmt, ...)
2041 len = vsnprintf(tmp, SZ, fmt, ap);
2042 buf_write(buf, tmp, len);
2046 void buf_write(struct buffer *buf, const char *s, int len)
2048 if (buf->size - buf->pos < len) {
2049 buf->size += len + SZ;
2050 buf->p = NOFAIL(realloc(buf->p, buf->size));
2052 strncpy(buf->p + buf->pos, s, len);
2056 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2058 const char *e = is_vmlinux(m) ?"":".ko";
2062 fatal("modpost: GPL-incompatible module %s%s "
2063 "uses GPL-only symbol '%s'\n", m, e, s);
2065 case export_unused_gpl:
2066 fatal("modpost: GPL-incompatible module %s%s "
2067 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2069 case export_gpl_future:
2070 warn("modpost: GPL-incompatible module %s%s "
2071 "uses future GPL-only symbol '%s'\n", m, e, s);
2075 case export_unknown:
2081 static void check_for_unused(enum export exp, const char *m, const char *s)
2083 const char *e = is_vmlinux(m) ?"":".ko";
2087 case export_unused_gpl:
2088 warn("modpost: module %s%s "
2089 "uses symbol '%s' marked UNUSED\n", m, e, s);
2097 static void check_exports(struct module *mod)
2099 struct symbol *s, *exp;
2101 for (s = mod->unres; s; s = s->next) {
2102 const char *basename;
2103 exp = find_symbol(s->name);
2104 if (!exp || exp->module == mod)
2106 basename = strrchr(mod->name, '/');
2110 basename = mod->name;
2111 if (!mod->gpl_compatible)
2112 check_for_gpl_usage(exp->export, basename, exp->name);
2113 check_for_unused(exp->export, basename, exp->name);
2118 * Header for the generated file
2120 static void add_header(struct buffer *b, struct module *mod)
2122 buf_printf(b, "#include <linux/module.h>\n");
2123 buf_printf(b, "#include <linux/vermagic.h>\n");
2124 buf_printf(b, "#include <linux/compiler.h>\n");
2125 buf_printf(b, "\n");
2126 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2127 buf_printf(b, "\n");
2128 buf_printf(b, "__visible struct module __this_module\n");
2129 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2130 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2132 buf_printf(b, "\t.init = init_module,\n");
2133 if (mod->has_cleanup)
2134 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2135 "\t.exit = cleanup_module,\n"
2137 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2138 buf_printf(b, "};\n");
2141 static void add_intree_flag(struct buffer *b, int is_intree)
2144 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2147 /* Cannot check for assembler */
2148 static void add_retpoline(struct buffer *b)
2150 buf_printf(b, "\n#ifdef RETPOLINE\n");
2151 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2152 buf_printf(b, "#endif\n");
2155 static void add_staging_flag(struct buffer *b, const char *name)
2157 static const char *staging_dir = "drivers/staging";
2159 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2160 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2163 /* In kernel, this size is defined in linux/module.h;
2164 * here we use Elf_Addr instead of long for covering cross-compile
2166 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2169 * Record CRCs for unresolved symbols
2171 static int add_versions(struct buffer *b, struct module *mod)
2173 struct symbol *s, *exp;
2176 for (s = mod->unres; s; s = s->next) {
2177 exp = find_symbol(s->name);
2178 if (!exp || exp->module == mod) {
2179 if (have_vmlinux && !s->weak) {
2180 if (warn_unresolved) {
2181 warn("\"%s\" [%s.ko] undefined!\n",
2182 s->name, mod->name);
2184 merror("\"%s\" [%s.ko] undefined!\n",
2185 s->name, mod->name);
2191 s->module = exp->module;
2192 s->crc_valid = exp->crc_valid;
2199 buf_printf(b, "\n");
2200 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2201 buf_printf(b, "__used\n");
2202 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2204 for (s = mod->unres; s; s = s->next) {
2207 if (!s->crc_valid) {
2208 warn("\"%s\" [%s.ko] has no CRC!\n",
2209 s->name, mod->name);
2212 if (strlen(s->name) >= MODULE_NAME_LEN) {
2213 merror("too long symbol \"%s\" [%s.ko]\n",
2214 s->name, mod->name);
2218 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2222 buf_printf(b, "};\n");
2227 static void add_depends(struct buffer *b, struct module *mod,
2228 struct module *modules)
2234 for (m = modules; m; m = m->next)
2235 m->seen = is_vmlinux(m->name);
2237 buf_printf(b, "\n");
2238 buf_printf(b, "static const char __module_depends[]\n");
2239 buf_printf(b, "__used\n");
2240 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2241 buf_printf(b, "\"depends=");
2242 for (s = mod->unres; s; s = s->next) {
2247 if (s->module->seen)
2250 s->module->seen = 1;
2251 p = strrchr(s->module->name, '/');
2255 p = s->module->name;
2256 buf_printf(b, "%s%s", first ? "" : ",", p);
2259 buf_printf(b, "\";\n");
2262 static void add_srcversion(struct buffer *b, struct module *mod)
2264 if (mod->srcversion[0]) {
2265 buf_printf(b, "\n");
2266 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2271 static void write_if_changed(struct buffer *b, const char *fname)
2277 file = fopen(fname, "r");
2281 if (fstat(fileno(file), &st) < 0)
2284 if (st.st_size != b->pos)
2287 tmp = NOFAIL(malloc(b->pos));
2288 if (fread(tmp, 1, b->pos, file) != b->pos)
2291 if (memcmp(tmp, b->p, b->pos) != 0)
2303 file = fopen(fname, "w");
2308 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2315 /* parse Module.symvers file. line format:
2316 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2318 static void read_dump(const char *fname, unsigned int kernel)
2320 unsigned long size, pos = 0;
2321 void *file = grab_file(fname, &size);
2325 /* No symbol versions, silently ignore */
2328 while ((line = get_next_line(&pos, file, size))) {
2329 char *symname, *modname, *d, *export, *end;
2334 if (!(symname = strchr(line, '\t')))
2337 if (!(modname = strchr(symname, '\t')))
2340 if ((export = strchr(modname, '\t')) != NULL)
2342 if (export && ((end = strchr(export, '\t')) != NULL))
2344 crc = strtoul(line, &d, 16);
2345 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2347 mod = find_module(modname);
2349 if (is_vmlinux(modname))
2351 mod = new_module(modname);
2354 s = sym_add_exported(symname, mod, export_no(export));
2357 sym_update_crc(symname, mod, crc, export_no(export));
2359 release_file(file, size);
2362 release_file(file, size);
2363 fatal("parse error in symbol dump file\n");
2366 /* For normal builds always dump all symbols.
2367 * For external modules only dump symbols
2368 * that are not read from kernel Module.symvers.
2370 static int dump_sym(struct symbol *sym)
2372 if (!external_module)
2374 if (sym->vmlinux || sym->kernel)
2379 static void write_dump(const char *fname)
2381 struct buffer buf = { };
2382 struct symbol *symbol;
2385 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2386 symbol = symbolhash[n];
2388 if (dump_sym(symbol))
2389 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2390 symbol->crc, symbol->name,
2391 symbol->module->name,
2392 export_str(symbol->export));
2393 symbol = symbol->next;
2396 write_if_changed(&buf, fname);
2399 struct ext_sym_list {
2400 struct ext_sym_list *next;
2404 int main(int argc, char **argv)
2407 struct buffer buf = { };
2408 char *kernel_read = NULL, *module_read = NULL;
2409 char *dump_write = NULL, *files_source = NULL;
2412 struct ext_sym_list *extsym_iter;
2413 struct ext_sym_list *extsym_start = NULL;
2415 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2418 kernel_read = optarg;
2421 module_read = optarg;
2422 external_module = 1;
2425 external_module = 1;
2427 NOFAIL(malloc(sizeof(*extsym_iter)));
2428 extsym_iter->next = extsym_start;
2429 extsym_iter->file = optarg;
2430 extsym_start = extsym_iter;
2436 ignore_missing_files = 1;
2439 dump_write = optarg;
2445 vmlinux_section_warnings = 0;
2448 sec_mismatch_verbose = 0;
2451 files_source = optarg;
2454 warn_unresolved = 1;
2457 sec_mismatch_fatal = 1;
2465 read_dump(kernel_read, 1);
2467 read_dump(module_read, 0);
2468 while (extsym_start) {
2469 read_dump(extsym_start->file, 0);
2470 extsym_iter = extsym_start->next;
2472 extsym_start = extsym_iter;
2475 while (optind < argc)
2476 read_symbols(argv[optind++]);
2479 read_symbols_from_files(files_source);
2481 for (mod = modules; mod; mod = mod->next) {
2489 for (mod = modules; mod; mod = mod->next) {
2490 char fname[PATH_MAX];
2497 add_header(&buf, mod);
2498 add_intree_flag(&buf, !external_module);
2499 add_retpoline(&buf);
2500 add_staging_flag(&buf, mod->name);
2501 err |= add_versions(&buf, mod);
2502 add_depends(&buf, mod, modules);
2503 add_moddevtable(&buf, mod);
2504 add_srcversion(&buf, mod);
2506 sprintf(fname, "%s.mod.c", mod->name);
2507 write_if_changed(&buf, fname);
2510 write_dump(dump_write);
2511 if (sec_mismatch_count) {
2512 if (!sec_mismatch_verbose) {
2513 warn("modpost: Found %d section mismatch(es).\n"
2514 "To see full details build your kernel with:\n"
2515 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2516 sec_mismatch_count);
2518 if (sec_mismatch_fatal) {
2519 fatal("modpost: Section mismatches detected.\n"
2520 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");