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 */
845 * This is used to find sections missing the SHF_ALLOC flag.
846 * The cause of this is often a section specified in assembler
847 * without "ax" / "aw".
849 static void check_section(const char *modname, struct elf_info *elf,
852 const char *sec = sech_name(elf, sechdr);
854 if (sechdr->sh_type == SHT_PROGBITS &&
855 !(sechdr->sh_flags & SHF_ALLOC) &&
856 !match(sec, section_white_list)) {
857 warn("%s (%s): unexpected non-allocatable section.\n"
858 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
859 "Note that for example <linux/init.h> contains\n"
860 "section definitions for use in .S files.\n\n",
867 #define ALL_INIT_DATA_SECTIONS \
868 ".init.setup", ".init.rodata", ".meminit.rodata", \
869 ".init.data", ".meminit.data"
870 #define ALL_EXIT_DATA_SECTIONS \
871 ".exit.data", ".memexit.data"
873 #define ALL_INIT_TEXT_SECTIONS \
874 ".init.text", ".meminit.text"
875 #define ALL_EXIT_TEXT_SECTIONS \
876 ".exit.text", ".memexit.text"
878 #define ALL_PCI_INIT_SECTIONS \
879 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
880 ".pci_fixup_enable", ".pci_fixup_resume", \
881 ".pci_fixup_resume_early", ".pci_fixup_suspend"
883 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
884 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
886 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
887 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
889 #define DATA_SECTIONS ".data", ".data.rel"
890 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
892 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
893 ".fixup", ".entry.text", ".exception.text", ".text.*", \
896 #define INIT_SECTIONS ".init.*"
897 #define MEM_INIT_SECTIONS ".meminit.*"
899 #define EXIT_SECTIONS ".exit.*"
900 #define MEM_EXIT_SECTIONS ".memexit.*"
902 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
903 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
905 /* init data sections */
906 static const char *const init_data_sections[] =
907 { ALL_INIT_DATA_SECTIONS, NULL };
909 /* all init sections */
910 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
912 /* All init and exit sections (code + data) */
913 static const char *const init_exit_sections[] =
914 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
916 /* all text sections */
917 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
920 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
923 /* symbols in .data that may refer to init/exit sections */
924 #define DEFAULT_SYMBOL_WHITE_LIST \
926 "*_template", /* scsi uses *_template a lot */ \
927 "*_timer", /* arm uses ops structures named _timer a lot */ \
928 "*_sht", /* scsi also used *_sht to some extent */ \
934 static const char *const head_sections[] = { ".head.text*", NULL };
935 static const char *const linker_symbols[] =
936 { "__init_begin", "_sinittext", "_einittext", NULL };
937 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
944 XXXINIT_TO_SOME_INIT,
945 XXXEXIT_TO_SOME_EXIT,
946 ANY_INIT_TO_ANY_EXIT,
947 ANY_EXIT_TO_ANY_INIT,
953 * Describe how to match sections on different criterias:
955 * @fromsec: Array of sections to be matched.
957 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
958 * this array is forbidden (black-list). Can be empty.
960 * @good_tosec: Relocations applied to a section in @fromsec must be
961 * targetting sections in this array (white-list). Can be empty.
963 * @mismatch: Type of mismatch.
965 * @symbol_white_list: Do not match a relocation to a symbol in this list
966 * even if it is targetting a section in @bad_to_sec.
968 * @handler: Specific handler to call when a match is found. If NULL,
969 * default_mismatch_handler() will be called.
972 struct sectioncheck {
973 const char *fromsec[20];
974 const char *bad_tosec[20];
975 const char *good_tosec[20];
976 enum mismatch mismatch;
977 const char *symbol_white_list[20];
978 void (*handler)(const char *modname, struct elf_info *elf,
979 const struct sectioncheck* const mismatch,
980 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
984 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
985 const struct sectioncheck* const mismatch,
986 Elf_Rela *r, Elf_Sym *sym,
987 const char *fromsec);
989 static const struct sectioncheck sectioncheck[] = {
990 /* Do not reference init/exit code/data from
991 * normal code and data
994 .fromsec = { TEXT_SECTIONS, NULL },
995 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
996 .mismatch = TEXT_TO_ANY_INIT,
997 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1000 .fromsec = { DATA_SECTIONS, NULL },
1001 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1002 .mismatch = DATA_TO_ANY_INIT,
1003 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1006 .fromsec = { DATA_SECTIONS, NULL },
1007 .bad_tosec = { INIT_SECTIONS, NULL },
1008 .mismatch = DATA_TO_ANY_INIT,
1009 .symbol_white_list = {
1010 "*_template", "*_timer", "*_sht", "*_ops",
1011 "*_probe", "*_probe_one", "*_console", NULL
1015 .fromsec = { TEXT_SECTIONS, NULL },
1016 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1017 .mismatch = TEXT_TO_ANY_EXIT,
1018 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1021 .fromsec = { DATA_SECTIONS, NULL },
1022 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1023 .mismatch = DATA_TO_ANY_EXIT,
1024 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1026 /* Do not reference init code/data from meminit code/data */
1028 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1029 .bad_tosec = { INIT_SECTIONS, NULL },
1030 .mismatch = XXXINIT_TO_SOME_INIT,
1031 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1033 /* Do not reference exit code/data from memexit code/data */
1035 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1036 .bad_tosec = { EXIT_SECTIONS, NULL },
1037 .mismatch = XXXEXIT_TO_SOME_EXIT,
1038 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1040 /* Do not use exit code/data from init code */
1042 .fromsec = { ALL_INIT_SECTIONS, NULL },
1043 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1044 .mismatch = ANY_INIT_TO_ANY_EXIT,
1045 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1047 /* Do not use init code/data from exit code */
1049 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1050 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1051 .mismatch = ANY_EXIT_TO_ANY_INIT,
1052 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1055 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1056 .bad_tosec = { INIT_SECTIONS, NULL },
1057 .mismatch = ANY_INIT_TO_ANY_EXIT,
1058 .symbol_white_list = { NULL },
1060 /* Do not export init/exit functions or data */
1062 .fromsec = { "__ksymtab*", NULL },
1063 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1064 .mismatch = EXPORT_TO_INIT_EXIT,
1065 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1068 .fromsec = { "__ex_table", NULL },
1069 /* If you're adding any new black-listed sections in here, consider
1070 * adding a special 'printer' for them in scripts/check_extable.
1072 .bad_tosec = { ".altinstr_replacement", NULL },
1073 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1074 .mismatch = EXTABLE_TO_NON_TEXT,
1075 .handler = extable_mismatch_handler,
1079 static const struct sectioncheck *section_mismatch(
1080 const char *fromsec, const char *tosec)
1083 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1084 const struct sectioncheck *check = §ioncheck[0];
1087 * The target section could be the SHT_NUL section when we're
1088 * handling relocations to un-resolved symbols, trying to match it
1089 * doesn't make much sense and causes build failures on parisc and
1090 * mn10300 architectures.
1095 for (i = 0; i < elems; i++) {
1096 if (match(fromsec, check->fromsec)) {
1097 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1099 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1108 * Whitelist to allow certain references to pass with no warning.
1111 * If a module parameter is declared __initdata and permissions=0
1112 * then this is legal despite the warning generated.
1113 * We cannot see value of permissions here, so just ignore
1115 * The pattern is identified by:
1116 * tosec = .init.data
1121 * module_param_call() ops can refer to __init set function if permissions=0
1122 * The pattern is identified by:
1123 * tosec = .init.text
1125 * atsym = __param_ops_*
1128 * Many drivers utilise a *driver container with references to
1129 * add, remove, probe functions etc.
1130 * the pattern is identified by:
1131 * tosec = init or exit section
1132 * fromsec = data section
1133 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1134 * *probe_one, *_console, *_timer
1137 * Whitelist all references from .head.text to any init section
1140 * Some symbols belong to init section but still it is ok to reference
1141 * these from non-init sections as these symbols don't have any memory
1142 * allocated for them and symbol address and value are same. So even
1143 * if init section is freed, its ok to reference those symbols.
1144 * For ex. symbols marking the init section boundaries.
1145 * This pattern is identified by
1146 * refsymname = __init_begin, _sinittext, _einittext
1149 * GCC may optimize static inlines when fed constant arg(s) resulting
1150 * in functions like cpumask_empty() -- generating an associated symbol
1151 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1152 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1153 * meaningless section warning. May need to add isra symbols too...
1154 * This pattern is identified by
1155 * tosec = init section
1156 * fromsec = text section
1157 * refsymname = *.constprop.*
1160 * Hide section mismatch warnings for ELF local symbols. The goal
1161 * is to eliminate false positive modpost warnings caused by
1162 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1163 * Autogenerated symbol names bypass modpost's "Pattern 2"
1164 * whitelisting, which relies on pattern-matching against symbol
1165 * names to work. (One situation where gcc can autogenerate ELF
1166 * local symbols is when "-fsection-anchors" is used.)
1168 static int secref_whitelist(const struct sectioncheck *mismatch,
1169 const char *fromsec, const char *fromsym,
1170 const char *tosec, const char *tosym)
1172 /* Check for pattern 1 */
1173 if (match(tosec, init_data_sections) &&
1174 match(fromsec, data_sections) &&
1175 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1178 /* Check for pattern 1a */
1179 if (strcmp(tosec, ".init.text") == 0 &&
1180 match(fromsec, data_sections) &&
1181 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1184 /* Check for pattern 2 */
1185 if (match(tosec, init_exit_sections) &&
1186 match(fromsec, data_sections) &&
1187 match(fromsym, mismatch->symbol_white_list))
1190 /* Check for pattern 3 */
1191 if (match(fromsec, head_sections) &&
1192 match(tosec, init_sections))
1195 /* Check for pattern 4 */
1196 if (match(tosym, linker_symbols))
1199 /* Check for pattern 5 */
1200 if (match(fromsec, text_sections) &&
1201 match(tosec, init_sections) &&
1202 match(fromsym, optim_symbols))
1205 /* Check for pattern 6 */
1206 if (strstarts(fromsym, ".L"))
1212 static inline int is_arm_mapping_symbol(const char *str)
1214 return str[0] == '$' && strchr("axtd", str[1])
1215 && (str[2] == '\0' || str[2] == '.');
1219 * If there's no name there, ignore it; likewise, ignore it if it's
1220 * one of the magic symbols emitted used by current ARM tools.
1222 * Otherwise if find_symbols_between() returns those symbols, they'll
1223 * fail the whitelist tests and cause lots of false alarms ... fixable
1224 * only by merging __exit and __init sections into __text, bloating
1225 * the kernel (which is especially evil on embedded platforms).
1227 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1229 const char *name = elf->strtab + sym->st_name;
1231 if (!name || !strlen(name))
1233 return !is_arm_mapping_symbol(name);
1237 * Find symbol based on relocation record info.
1238 * In some cases the symbol supplied is a valid symbol so
1239 * return refsym. If st_name != 0 we assume this is a valid symbol.
1240 * In other cases the symbol needs to be looked up in the symbol table
1241 * based on section and address.
1243 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1247 Elf_Sym *near = NULL;
1248 Elf64_Sword distance = 20;
1250 unsigned int relsym_secindex;
1252 if (relsym->st_name != 0)
1255 relsym_secindex = get_secindex(elf, relsym);
1256 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1257 if (get_secindex(elf, sym) != relsym_secindex)
1259 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1261 if (!is_valid_name(elf, sym))
1263 if (sym->st_value == addr)
1265 /* Find a symbol nearby - addr are maybe negative */
1266 d = sym->st_value - addr;
1268 d = addr - sym->st_value;
1274 /* We need a close match */
1282 * Find symbols before or equal addr and after addr - in the section sec.
1283 * If we find two symbols with equal offset prefer one with a valid name.
1284 * The ELF format may have a better way to detect what type of symbol
1285 * it is, but this works for now.
1287 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1291 Elf_Sym *near = NULL;
1292 Elf_Addr distance = ~0;
1294 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1297 if (is_shndx_special(sym->st_shndx))
1299 symsec = sec_name(elf, get_secindex(elf, sym));
1300 if (strcmp(symsec, sec) != 0)
1302 if (!is_valid_name(elf, sym))
1304 if (sym->st_value <= addr) {
1305 if ((addr - sym->st_value) < distance) {
1306 distance = addr - sym->st_value;
1308 } else if ((addr - sym->st_value) == distance) {
1317 * Convert a section name to the function/data attribute
1318 * .init.text => __init
1319 * .memexitconst => __memconst
1322 * The memory of returned value has been allocated on a heap. The user of this
1323 * method should free it after usage.
1325 static char *sec2annotation(const char *s)
1327 if (match(s, init_exit_sections)) {
1328 char *p = NOFAIL(malloc(20));
1335 while (*s && *s != '.')
1340 if (strstr(s, "rodata") != NULL)
1341 strcat(p, "const ");
1342 else if (strstr(s, "data") != NULL)
1348 return NOFAIL(strdup(""));
1352 static int is_function(Elf_Sym *sym)
1355 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1360 static void print_section_list(const char * const list[20])
1362 const char *const *s = list;
1365 fprintf(stderr, "%s", *s);
1368 fprintf(stderr, ", ");
1370 fprintf(stderr, "\n");
1373 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1376 case 0: *name = "variable"; *name_p = ""; break;
1377 case 1: *name = "function"; *name_p = "()"; break;
1378 default: *name = "(unknown reference)"; *name_p = ""; break;
1383 * Print a warning about a section mismatch.
1384 * Try to find symbols near it so user can find it.
1385 * Check whitelist before warning - it may be a false positive.
1387 static void report_sec_mismatch(const char *modname,
1388 const struct sectioncheck *mismatch,
1389 const char *fromsec,
1390 unsigned long long fromaddr,
1391 const char *fromsym,
1393 const char *tosec, const char *tosym,
1396 const char *from, *from_p;
1397 const char *to, *to_p;
1401 sec_mismatch_count++;
1402 if (!sec_mismatch_verbose)
1405 get_pretty_name(from_is_func, &from, &from_p);
1406 get_pretty_name(to_is_func, &to, &to_p);
1408 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1409 "to the %s %s:%s%s\n",
1410 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1413 switch (mismatch->mismatch) {
1414 case TEXT_TO_ANY_INIT:
1415 prl_from = sec2annotation(fromsec);
1416 prl_to = sec2annotation(tosec);
1418 "The function %s%s() references\n"
1420 "This is often because %s lacks a %s\n"
1421 "annotation or the annotation of %s is wrong.\n",
1423 to, prl_to, tosym, to_p,
1424 fromsym, prl_to, tosym);
1428 case DATA_TO_ANY_INIT: {
1429 prl_to = sec2annotation(tosec);
1431 "The variable %s references\n"
1433 "If the reference is valid then annotate the\n"
1434 "variable with __init* or __refdata (see linux/init.h) "
1435 "or name the variable:\n",
1436 fromsym, to, prl_to, tosym, to_p);
1437 print_section_list(mismatch->symbol_white_list);
1441 case TEXT_TO_ANY_EXIT:
1442 prl_to = sec2annotation(tosec);
1444 "The function %s() references a %s in an exit section.\n"
1445 "Often the %s %s%s has valid usage outside the exit section\n"
1446 "and the fix is to remove the %sannotation of %s.\n",
1447 fromsym, to, to, tosym, to_p, prl_to, tosym);
1450 case DATA_TO_ANY_EXIT: {
1451 prl_to = sec2annotation(tosec);
1453 "The variable %s references\n"
1455 "If the reference is valid then annotate the\n"
1456 "variable with __exit* (see linux/init.h) or "
1457 "name the variable:\n",
1458 fromsym, to, prl_to, tosym, to_p);
1459 print_section_list(mismatch->symbol_white_list);
1463 case XXXINIT_TO_SOME_INIT:
1464 case XXXEXIT_TO_SOME_EXIT:
1465 prl_from = sec2annotation(fromsec);
1466 prl_to = sec2annotation(tosec);
1468 "The %s %s%s%s references\n"
1470 "If %s is only used by %s then\n"
1471 "annotate %s with a matching annotation.\n",
1472 from, prl_from, fromsym, from_p,
1473 to, prl_to, tosym, to_p,
1474 tosym, fromsym, tosym);
1478 case ANY_INIT_TO_ANY_EXIT:
1479 prl_from = sec2annotation(fromsec);
1480 prl_to = sec2annotation(tosec);
1482 "The %s %s%s%s references\n"
1484 "This is often seen when error handling "
1485 "in the init function\n"
1486 "uses functionality in the exit path.\n"
1487 "The fix is often to remove the %sannotation of\n"
1488 "%s%s so it may be used outside an exit section.\n",
1489 from, prl_from, fromsym, from_p,
1490 to, prl_to, tosym, to_p,
1491 prl_to, tosym, to_p);
1495 case ANY_EXIT_TO_ANY_INIT:
1496 prl_from = sec2annotation(fromsec);
1497 prl_to = sec2annotation(tosec);
1499 "The %s %s%s%s references\n"
1501 "This is often seen when error handling "
1502 "in the exit function\n"
1503 "uses functionality in the init path.\n"
1504 "The fix is often to remove the %sannotation of\n"
1505 "%s%s so it may be used outside an init section.\n",
1506 from, prl_from, fromsym, from_p,
1507 to, prl_to, tosym, to_p,
1508 prl_to, tosym, to_p);
1512 case EXPORT_TO_INIT_EXIT:
1513 prl_to = sec2annotation(tosec);
1515 "The symbol %s is exported and annotated %s\n"
1516 "Fix this by removing the %sannotation of %s "
1517 "or drop the export.\n",
1518 tosym, prl_to, prl_to, tosym);
1521 case EXTABLE_TO_NON_TEXT:
1522 fatal("There's a special handler for this mismatch type, "
1523 "we should never get here.");
1526 fprintf(stderr, "\n");
1529 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1530 const struct sectioncheck* const mismatch,
1531 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1537 const char *fromsym;
1539 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1540 fromsym = sym_name(elf, from);
1542 if (!strncmp(fromsym, "reference___initcall",
1543 sizeof("reference___initcall")-1))
1546 tosec = sec_name(elf, get_secindex(elf, sym));
1547 to = find_elf_symbol(elf, r->r_addend, sym);
1548 tosym = sym_name(elf, to);
1550 /* check whitelist - we may ignore it */
1551 if (secref_whitelist(mismatch,
1552 fromsec, fromsym, tosec, tosym)) {
1553 report_sec_mismatch(modname, mismatch,
1554 fromsec, r->r_offset, fromsym,
1555 is_function(from), tosec, tosym,
1560 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1562 if (section_index > elf->num_sections)
1563 fatal("section_index is outside elf->num_sections!\n");
1565 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1569 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1570 * to know the sizeof(struct exception_table_entry) for the target architecture.
1572 static unsigned int extable_entry_size = 0;
1573 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1576 * If we're currently checking the second relocation within __ex_table,
1577 * that relocation offset tells us the offsetof(struct
1578 * exception_table_entry, fixup) which is equal to sizeof(struct
1579 * exception_table_entry) divided by two. We use that to our advantage
1580 * since there's no portable way to get that size as every architecture
1581 * seems to go with different sized types. Not pretty but better than
1582 * hard-coding the size for every architecture..
1584 if (!extable_entry_size)
1585 extable_entry_size = r->r_offset * 2;
1588 static inline bool is_extable_fault_address(Elf_Rela *r)
1591 * extable_entry_size is only discovered after we've handled the
1592 * _second_ relocation in __ex_table, so only abort when we're not
1593 * handling the first reloc and extable_entry_size is zero.
1595 if (r->r_offset && extable_entry_size == 0)
1596 fatal("extable_entry size hasn't been discovered!\n");
1598 return ((r->r_offset == 0) ||
1599 (r->r_offset % extable_entry_size == 0));
1602 #define is_second_extable_reloc(Start, Cur, Sec) \
1603 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1605 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1606 const struct sectioncheck* const mismatch,
1607 Elf_Rela* r, Elf_Sym* sym,
1608 const char* fromsec, const char* tosec)
1610 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1611 const char* fromsym_name = sym_name(elf, fromsym);
1612 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1613 const char* tosym_name = sym_name(elf, tosym);
1614 const char* from_pretty_name;
1615 const char* from_pretty_name_p;
1616 const char* to_pretty_name;
1617 const char* to_pretty_name_p;
1619 get_pretty_name(is_function(fromsym),
1620 &from_pretty_name, &from_pretty_name_p);
1621 get_pretty_name(is_function(tosym),
1622 &to_pretty_name, &to_pretty_name_p);
1624 warn("%s(%s+0x%lx): Section mismatch in reference"
1625 " from the %s %s%s to the %s %s:%s%s\n",
1626 modname, fromsec, (long)r->r_offset, from_pretty_name,
1627 fromsym_name, from_pretty_name_p,
1628 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1630 if (!match(tosec, mismatch->bad_tosec) &&
1631 is_executable_section(elf, get_secindex(elf, sym)))
1633 "The relocation at %s+0x%lx references\n"
1634 "section \"%s\" which is not in the list of\n"
1635 "authorized sections. If you're adding a new section\n"
1636 "and/or if this reference is valid, add \"%s\" to the\n"
1637 "list of authorized sections to jump to on fault.\n"
1638 "This can be achieved by adding \"%s\" to \n"
1639 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1640 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1643 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1644 const struct sectioncheck* const mismatch,
1645 Elf_Rela* r, Elf_Sym* sym,
1646 const char *fromsec)
1648 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1650 sec_mismatch_count++;
1652 if (sec_mismatch_verbose)
1653 report_extable_warnings(modname, elf, mismatch, r, sym,
1656 if (match(tosec, mismatch->bad_tosec))
1657 fatal("The relocation at %s+0x%lx references\n"
1658 "section \"%s\" which is black-listed.\n"
1659 "Something is seriously wrong and should be fixed.\n"
1660 "You might get more information about where this is\n"
1661 "coming from by using scripts/check_extable.sh %s\n",
1662 fromsec, (long)r->r_offset, tosec, modname);
1663 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1664 if (is_extable_fault_address(r))
1665 fatal("The relocation at %s+0x%lx references\n"
1666 "section \"%s\" which is not executable, IOW\n"
1667 "it is not possible for the kernel to fault\n"
1668 "at that address. Something is seriously wrong\n"
1669 "and should be fixed.\n",
1670 fromsec, (long)r->r_offset, tosec);
1672 fatal("The relocation at %s+0x%lx references\n"
1673 "section \"%s\" which is not executable, IOW\n"
1674 "the kernel will fault if it ever tries to\n"
1675 "jump to it. Something is seriously wrong\n"
1676 "and should be fixed.\n",
1677 fromsec, (long)r->r_offset, tosec);
1681 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1682 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1684 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1685 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1688 if (mismatch->handler)
1689 mismatch->handler(modname, elf, mismatch,
1692 default_mismatch_handler(modname, elf, mismatch,
1697 static unsigned int *reloc_location(struct elf_info *elf,
1698 Elf_Shdr *sechdr, Elf_Rela *r)
1700 Elf_Shdr *sechdrs = elf->sechdrs;
1701 int section = sechdr->sh_info;
1703 return (void *)elf->hdr + sechdrs[section].sh_offset +
1707 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1709 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1710 unsigned int *location = reloc_location(elf, sechdr, r);
1714 r->r_addend = TO_NATIVE(*location);
1717 r->r_addend = TO_NATIVE(*location) + 4;
1718 /* For CONFIG_RELOCATABLE=y */
1719 if (elf->hdr->e_type == ET_EXEC)
1720 r->r_addend += r->r_offset;
1727 #define R_ARM_CALL 28
1729 #ifndef R_ARM_JUMP24
1730 #define R_ARM_JUMP24 29
1733 #ifndef R_ARM_THM_CALL
1734 #define R_ARM_THM_CALL 10
1736 #ifndef R_ARM_THM_JUMP24
1737 #define R_ARM_THM_JUMP24 30
1739 #ifndef R_ARM_THM_JUMP19
1740 #define R_ARM_THM_JUMP19 51
1743 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1745 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1749 /* From ARM ABI: (S + A) | T */
1750 r->r_addend = (int)(long)
1751 (elf->symtab_start + ELF_R_SYM(r->r_info));
1756 case R_ARM_THM_CALL:
1757 case R_ARM_THM_JUMP24:
1758 case R_ARM_THM_JUMP19:
1759 /* From ARM ABI: ((S + A) | T) - P */
1760 r->r_addend = (int)(long)(elf->hdr +
1762 (r->r_offset - sechdr->sh_addr));
1770 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1772 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1773 unsigned int *location = reloc_location(elf, sechdr, r);
1776 if (r_typ == R_MIPS_HI16)
1777 return 1; /* skip this */
1778 inst = TO_NATIVE(*location);
1781 r->r_addend = inst & 0xffff;
1784 r->r_addend = (inst & 0x03ffffff) << 2;
1793 static void section_rela(const char *modname, struct elf_info *elf,
1800 const char *fromsec;
1802 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1803 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1805 fromsec = sech_name(elf, sechdr);
1806 fromsec += strlen(".rela");
1807 /* if from section (name) is know good then skip it */
1808 if (match(fromsec, section_white_list))
1811 for (rela = start; rela < stop; rela++) {
1812 r.r_offset = TO_NATIVE(rela->r_offset);
1813 #if KERNEL_ELFCLASS == ELFCLASS64
1814 if (elf->hdr->e_machine == EM_MIPS) {
1816 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1817 r_sym = TO_NATIVE(r_sym);
1818 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1819 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1821 r.r_info = TO_NATIVE(rela->r_info);
1822 r_sym = ELF_R_SYM(r.r_info);
1825 r.r_info = TO_NATIVE(rela->r_info);
1826 r_sym = ELF_R_SYM(r.r_info);
1828 r.r_addend = TO_NATIVE(rela->r_addend);
1829 sym = elf->symtab_start + r_sym;
1830 /* Skip special sections */
1831 if (is_shndx_special(sym->st_shndx))
1833 if (is_second_extable_reloc(start, rela, fromsec))
1834 find_extable_entry_size(fromsec, &r);
1835 check_section_mismatch(modname, elf, &r, sym, fromsec);
1839 static void section_rel(const char *modname, struct elf_info *elf,
1846 const char *fromsec;
1848 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1849 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1851 fromsec = sech_name(elf, sechdr);
1852 fromsec += strlen(".rel");
1853 /* if from section (name) is know good then skip it */
1854 if (match(fromsec, section_white_list))
1857 for (rel = start; rel < stop; rel++) {
1858 r.r_offset = TO_NATIVE(rel->r_offset);
1859 #if KERNEL_ELFCLASS == ELFCLASS64
1860 if (elf->hdr->e_machine == EM_MIPS) {
1862 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1863 r_sym = TO_NATIVE(r_sym);
1864 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1865 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1867 r.r_info = TO_NATIVE(rel->r_info);
1868 r_sym = ELF_R_SYM(r.r_info);
1871 r.r_info = TO_NATIVE(rel->r_info);
1872 r_sym = ELF_R_SYM(r.r_info);
1875 switch (elf->hdr->e_machine) {
1877 if (addend_386_rel(elf, sechdr, &r))
1881 if (addend_arm_rel(elf, sechdr, &r))
1885 if (addend_mips_rel(elf, sechdr, &r))
1889 sym = elf->symtab_start + r_sym;
1890 /* Skip special sections */
1891 if (is_shndx_special(sym->st_shndx))
1893 if (is_second_extable_reloc(start, rel, fromsec))
1894 find_extable_entry_size(fromsec, &r);
1895 check_section_mismatch(modname, elf, &r, sym, fromsec);
1900 * A module includes a number of sections that are discarded
1901 * either when loaded or when used as built-in.
1902 * For loaded modules all functions marked __init and all data
1903 * marked __initdata will be discarded when the module has been initialized.
1904 * Likewise for modules used built-in the sections marked __exit
1905 * are discarded because __exit marked function are supposed to be called
1906 * only when a module is unloaded which never happens for built-in modules.
1907 * The check_sec_ref() function traverses all relocation records
1908 * to find all references to a section that reference a section that will
1909 * be discarded and warns about it.
1911 static void check_sec_ref(struct module *mod, const char *modname,
1912 struct elf_info *elf)
1915 Elf_Shdr *sechdrs = elf->sechdrs;
1917 /* Walk through all sections */
1918 for (i = 0; i < elf->num_sections; i++) {
1919 check_section(modname, elf, &elf->sechdrs[i]);
1920 /* We want to process only relocation sections and not .init */
1921 if (sechdrs[i].sh_type == SHT_RELA)
1922 section_rela(modname, elf, &elf->sechdrs[i]);
1923 else if (sechdrs[i].sh_type == SHT_REL)
1924 section_rel(modname, elf, &elf->sechdrs[i]);
1928 static char *remove_dot(char *s)
1930 size_t n = strcspn(s, ".");
1933 size_t m = strspn(s + n + 1, "0123456789");
1934 if (m && (s[n + m] == '.' || s[n + m] == 0))
1940 static void read_symbols(char *modname)
1942 const char *symname;
1946 struct elf_info info = { };
1949 if (!parse_elf(&info, modname))
1952 mod = new_module(modname);
1954 /* When there's no vmlinux, don't print warnings about
1955 * unresolved symbols (since there'll be too many ;) */
1956 if (is_vmlinux(modname)) {
1961 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1962 if (info.modinfo && !license && !is_vmlinux(modname))
1963 warn("modpost: missing MODULE_LICENSE() in %s\n"
1964 "see include/linux/module.h for "
1965 "more information\n", modname);
1967 if (license_is_gpl_compatible(license))
1968 mod->gpl_compatible = 1;
1970 mod->gpl_compatible = 0;
1973 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1974 "license", license);
1977 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1978 symname = remove_dot(info.strtab + sym->st_name);
1980 handle_modversions(mod, &info, sym, symname);
1981 handle_moddevtable(mod, &info, sym, symname);
1983 if (!is_vmlinux(modname) ||
1984 (is_vmlinux(modname) && vmlinux_section_warnings))
1985 check_sec_ref(mod, modname, &info);
1987 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1989 maybe_frob_rcs_version(modname, version, info.modinfo,
1990 version - (char *)info.hdr);
1991 if (version || (all_versions && !is_vmlinux(modname)))
1992 get_src_version(modname, mod->srcversion,
1993 sizeof(mod->srcversion)-1);
1995 parse_elf_finish(&info);
1997 /* Our trick to get versioning for module struct etc. - it's
1998 * never passed as an argument to an exported function, so
1999 * the automatic versioning doesn't pick it up, but it's really
2000 * important anyhow */
2002 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2005 static void read_symbols_from_files(const char *filename)
2008 char fname[PATH_MAX];
2010 if (strcmp(filename, "-") != 0) {
2011 in = fopen(filename, "r");
2013 fatal("Can't open filenames file %s: %m", filename);
2016 while (fgets(fname, PATH_MAX, in) != NULL) {
2017 if (strends(fname, "\n"))
2018 fname[strlen(fname)-1] = '\0';
2019 read_symbols(fname);
2028 /* We first write the generated file into memory using the
2029 * following helper, then compare to the file on disk and
2030 * only update the later if anything changed */
2032 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2033 const char *fmt, ...)
2040 len = vsnprintf(tmp, SZ, fmt, ap);
2041 buf_write(buf, tmp, len);
2045 void buf_write(struct buffer *buf, const char *s, int len)
2047 if (buf->size - buf->pos < len) {
2048 buf->size += len + SZ;
2049 buf->p = NOFAIL(realloc(buf->p, buf->size));
2051 strncpy(buf->p + buf->pos, s, len);
2055 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2057 const char *e = is_vmlinux(m) ?"":".ko";
2061 fatal("modpost: GPL-incompatible module %s%s "
2062 "uses GPL-only symbol '%s'\n", m, e, s);
2064 case export_unused_gpl:
2065 fatal("modpost: GPL-incompatible module %s%s "
2066 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2068 case export_gpl_future:
2069 warn("modpost: GPL-incompatible module %s%s "
2070 "uses future GPL-only symbol '%s'\n", m, e, s);
2074 case export_unknown:
2080 static void check_for_unused(enum export exp, const char *m, const char *s)
2082 const char *e = is_vmlinux(m) ?"":".ko";
2086 case export_unused_gpl:
2087 warn("modpost: module %s%s "
2088 "uses symbol '%s' marked UNUSED\n", m, e, s);
2096 static void check_exports(struct module *mod)
2098 struct symbol *s, *exp;
2100 for (s = mod->unres; s; s = s->next) {
2101 const char *basename;
2102 exp = find_symbol(s->name);
2103 if (!exp || exp->module == mod)
2105 basename = strrchr(mod->name, '/');
2109 basename = mod->name;
2110 if (!mod->gpl_compatible)
2111 check_for_gpl_usage(exp->export, basename, exp->name);
2112 check_for_unused(exp->export, basename, exp->name);
2117 * Header for the generated file
2119 static void add_header(struct buffer *b, struct module *mod)
2121 buf_printf(b, "#include <linux/module.h>\n");
2122 buf_printf(b, "#include <linux/vermagic.h>\n");
2123 buf_printf(b, "#include <linux/compiler.h>\n");
2124 buf_printf(b, "\n");
2125 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2126 buf_printf(b, "\n");
2127 buf_printf(b, "__visible struct module __this_module\n");
2128 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2129 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2131 buf_printf(b, "\t.init = init_module,\n");
2132 if (mod->has_cleanup)
2133 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2134 "\t.exit = cleanup_module,\n"
2136 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2137 buf_printf(b, "};\n");
2140 static void add_intree_flag(struct buffer *b, int is_intree)
2143 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2146 /* Cannot check for assembler */
2147 static void add_retpoline(struct buffer *b)
2149 buf_printf(b, "\n#ifdef RETPOLINE\n");
2150 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2151 buf_printf(b, "#endif\n");
2154 static void add_staging_flag(struct buffer *b, const char *name)
2156 static const char *staging_dir = "drivers/staging";
2158 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2159 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2162 /* In kernel, this size is defined in linux/module.h;
2163 * here we use Elf_Addr instead of long for covering cross-compile
2165 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2168 * Record CRCs for unresolved symbols
2170 static int add_versions(struct buffer *b, struct module *mod)
2172 struct symbol *s, *exp;
2175 for (s = mod->unres; s; s = s->next) {
2176 exp = find_symbol(s->name);
2177 if (!exp || exp->module == mod) {
2178 if (have_vmlinux && !s->weak) {
2179 if (warn_unresolved) {
2180 warn("\"%s\" [%s.ko] undefined!\n",
2181 s->name, mod->name);
2183 merror("\"%s\" [%s.ko] undefined!\n",
2184 s->name, mod->name);
2190 s->module = exp->module;
2191 s->crc_valid = exp->crc_valid;
2198 buf_printf(b, "\n");
2199 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2200 buf_printf(b, "__used\n");
2201 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2203 for (s = mod->unres; s; s = s->next) {
2206 if (!s->crc_valid) {
2207 warn("\"%s\" [%s.ko] has no CRC!\n",
2208 s->name, mod->name);
2211 if (strlen(s->name) >= MODULE_NAME_LEN) {
2212 merror("too long symbol \"%s\" [%s.ko]\n",
2213 s->name, mod->name);
2217 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2221 buf_printf(b, "};\n");
2226 static void add_depends(struct buffer *b, struct module *mod,
2227 struct module *modules)
2233 for (m = modules; m; m = m->next)
2234 m->seen = is_vmlinux(m->name);
2236 buf_printf(b, "\n");
2237 buf_printf(b, "static const char __module_depends[]\n");
2238 buf_printf(b, "__used\n");
2239 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2240 buf_printf(b, "\"depends=");
2241 for (s = mod->unres; s; s = s->next) {
2246 if (s->module->seen)
2249 s->module->seen = 1;
2250 p = strrchr(s->module->name, '/');
2254 p = s->module->name;
2255 buf_printf(b, "%s%s", first ? "" : ",", p);
2258 buf_printf(b, "\";\n");
2261 static void add_srcversion(struct buffer *b, struct module *mod)
2263 if (mod->srcversion[0]) {
2264 buf_printf(b, "\n");
2265 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2270 static void write_if_changed(struct buffer *b, const char *fname)
2276 file = fopen(fname, "r");
2280 if (fstat(fileno(file), &st) < 0)
2283 if (st.st_size != b->pos)
2286 tmp = NOFAIL(malloc(b->pos));
2287 if (fread(tmp, 1, b->pos, file) != b->pos)
2290 if (memcmp(tmp, b->p, b->pos) != 0)
2302 file = fopen(fname, "w");
2307 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2314 /* parse Module.symvers file. line format:
2315 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2317 static void read_dump(const char *fname, unsigned int kernel)
2319 unsigned long size, pos = 0;
2320 void *file = grab_file(fname, &size);
2324 /* No symbol versions, silently ignore */
2327 while ((line = get_next_line(&pos, file, size))) {
2328 char *symname, *modname, *d, *export, *end;
2333 if (!(symname = strchr(line, '\t')))
2336 if (!(modname = strchr(symname, '\t')))
2339 if ((export = strchr(modname, '\t')) != NULL)
2341 if (export && ((end = strchr(export, '\t')) != NULL))
2343 crc = strtoul(line, &d, 16);
2344 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2346 mod = find_module(modname);
2348 if (is_vmlinux(modname))
2350 mod = new_module(modname);
2353 s = sym_add_exported(symname, mod, export_no(export));
2356 sym_update_crc(symname, mod, crc, export_no(export));
2358 release_file(file, size);
2361 release_file(file, size);
2362 fatal("parse error in symbol dump file\n");
2365 /* For normal builds always dump all symbols.
2366 * For external modules only dump symbols
2367 * that are not read from kernel Module.symvers.
2369 static int dump_sym(struct symbol *sym)
2371 if (!external_module)
2373 if (sym->vmlinux || sym->kernel)
2378 static void write_dump(const char *fname)
2380 struct buffer buf = { };
2381 struct symbol *symbol;
2384 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2385 symbol = symbolhash[n];
2387 if (dump_sym(symbol))
2388 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2389 symbol->crc, symbol->name,
2390 symbol->module->name,
2391 export_str(symbol->export));
2392 symbol = symbol->next;
2395 write_if_changed(&buf, fname);
2398 struct ext_sym_list {
2399 struct ext_sym_list *next;
2403 int main(int argc, char **argv)
2406 struct buffer buf = { };
2407 char *kernel_read = NULL, *module_read = NULL;
2408 char *dump_write = NULL, *files_source = NULL;
2411 struct ext_sym_list *extsym_iter;
2412 struct ext_sym_list *extsym_start = NULL;
2414 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2417 kernel_read = optarg;
2420 module_read = optarg;
2421 external_module = 1;
2424 external_module = 1;
2426 NOFAIL(malloc(sizeof(*extsym_iter)));
2427 extsym_iter->next = extsym_start;
2428 extsym_iter->file = optarg;
2429 extsym_start = extsym_iter;
2435 ignore_missing_files = 1;
2438 dump_write = optarg;
2444 vmlinux_section_warnings = 0;
2447 sec_mismatch_verbose = 0;
2450 files_source = optarg;
2453 warn_unresolved = 1;
2456 sec_mismatch_fatal = 1;
2464 read_dump(kernel_read, 1);
2466 read_dump(module_read, 0);
2467 while (extsym_start) {
2468 read_dump(extsym_start->file, 0);
2469 extsym_iter = extsym_start->next;
2471 extsym_start = extsym_iter;
2474 while (optind < argc)
2475 read_symbols(argv[optind++]);
2478 read_symbols_from_files(files_source);
2480 for (mod = modules; mod; mod = mod->next) {
2488 for (mod = modules; mod; mod = mod->next) {
2489 char fname[PATH_MAX];
2496 add_header(&buf, mod);
2497 add_intree_flag(&buf, !external_module);
2498 add_retpoline(&buf);
2499 add_staging_flag(&buf, mod->name);
2500 err |= add_versions(&buf, mod);
2501 add_depends(&buf, mod, modules);
2502 add_moddevtable(&buf, mod);
2503 add_srcversion(&buf, mod);
2505 sprintf(fname, "%s.mod.c", mod->name);
2506 write_if_changed(&buf, fname);
2509 write_dump(dump_write);
2510 if (sec_mismatch_count) {
2511 if (!sec_mismatch_verbose) {
2512 warn("modpost: Found %d section mismatch(es).\n"
2513 "To see full details build your kernel with:\n"
2514 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2515 sec_mismatch_count);
2517 if (sec_mismatch_fatal) {
2518 fatal("modpost: Section mismatches detected.\n"
2519 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");