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/linux/license.h"
24 /* Are we using CONFIG_MODVERSIONS? */
25 static int modversions = 0;
26 /* Warn about undefined symbols? (do so if we have vmlinux) */
27 static int have_vmlinux = 0;
28 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
29 static int all_versions = 0;
30 /* If we are modposting external module set to 1 */
31 static int external_module = 0;
32 /* Warn about section mismatch in vmlinux if set to 1 */
33 static int vmlinux_section_warnings = 1;
34 /* Only warn about unresolved symbols */
35 static int warn_unresolved = 0;
36 /* How a symbol is exported */
37 static int sec_mismatch_count = 0;
38 static int sec_mismatch_verbose = 1;
39 static int sec_mismatch_fatal = 0;
40 /* ignore missing files */
41 static int ignore_missing_files;
44 export_plain, export_unused, export_gpl,
45 export_unused_gpl, export_gpl_future, export_unknown
48 /* In kernel, this size is defined in linux/module.h;
49 * here we use Elf_Addr instead of long for covering cross-compile
52 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
54 #define PRINTF __attribute__ ((format (printf, 1, 2)))
56 PRINTF void fatal(const char *fmt, ...)
60 fprintf(stderr, "FATAL: ");
62 va_start(arglist, fmt);
63 vfprintf(stderr, fmt, arglist);
69 PRINTF void warn(const char *fmt, ...)
73 fprintf(stderr, "WARNING: ");
75 va_start(arglist, fmt);
76 vfprintf(stderr, fmt, arglist);
80 PRINTF void merror(const char *fmt, ...)
84 fprintf(stderr, "ERROR: ");
86 va_start(arglist, fmt);
87 vfprintf(stderr, fmt, arglist);
91 static inline bool strends(const char *str, const char *postfix)
93 if (strlen(str) < strlen(postfix))
96 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
99 static int is_vmlinux(const char *modname)
103 myname = strrchr(modname, '/');
109 return (strcmp(myname, "vmlinux") == 0) ||
110 (strcmp(myname, "vmlinux.o") == 0);
113 void *do_nofail(void *ptr, const char *expr)
116 fatal("modpost: Memory allocation failure: %s.\n", expr);
121 /* A list of all modules we processed */
122 static struct module *modules;
124 static struct module *find_module(const char *modname)
128 for (mod = modules; mod; mod = mod->next)
129 if (strcmp(mod->name, modname) == 0)
134 static struct module *new_module(const char *modname)
139 mod = NOFAIL(malloc(sizeof(*mod)));
140 memset(mod, 0, sizeof(*mod));
141 p = NOFAIL(strdup(modname));
143 /* strip trailing .o */
144 if (strends(p, ".o")) {
145 p[strlen(p) - 2] = '\0';
151 mod->gpl_compatible = -1;
158 /* A hash of all exported symbols,
159 * struct symbol is also used for lists of unresolved symbols */
161 #define SYMBOL_HASH_SIZE 1024
165 struct module *module;
169 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
170 unsigned int kernel:1; /* 1 if symbol is from kernel
171 * (only for external modules) **/
172 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
173 enum export export; /* Type of export */
177 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
179 /* This is based on the hash agorithm from gdbm, via tdb */
180 static inline unsigned int tdb_hash(const char *name)
182 unsigned value; /* Used to compute the hash value. */
183 unsigned i; /* Used to cycle through random values. */
185 /* Set the initial value from the key size. */
186 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
187 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
189 return (1103515243 * value + 12345);
193 * Allocate a new symbols for use in the hash of exported symbols or
194 * the list of unresolved symbols per module
196 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
199 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
201 memset(s, 0, sizeof(*s));
202 strcpy(s->name, name);
208 /* For the hash of exported symbols */
209 static struct symbol *new_symbol(const char *name, struct module *module,
215 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
216 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
217 new->module = module;
218 new->export = export;
222 static struct symbol *find_symbol(const char *name)
226 /* For our purposes, .foo matches foo. PPC64 needs this. */
230 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
231 if (strcmp(s->name, name) == 0)
237 static const struct {
241 { .str = "EXPORT_SYMBOL", .export = export_plain },
242 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
243 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
244 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
245 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
246 { .str = "(unknown)", .export = export_unknown },
250 static const char *export_str(enum export ex)
252 return export_list[ex].str;
255 static enum export export_no(const char *s)
260 return export_unknown;
261 for (i = 0; export_list[i].export != export_unknown; i++) {
262 if (strcmp(export_list[i].str, s) == 0)
263 return export_list[i].export;
265 return export_unknown;
268 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
270 return (void *)elf->hdr +
271 elf->sechdrs[elf->secindex_strings].sh_offset +
275 static const char *sec_name(struct elf_info *elf, int secindex)
277 return sech_name(elf, &elf->sechdrs[secindex]);
280 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
282 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
284 const char *secname = sec_name(elf, sec);
286 if (strstarts(secname, "___ksymtab+"))
288 else if (strstarts(secname, "___ksymtab_unused+"))
289 return export_unused;
290 else if (strstarts(secname, "___ksymtab_gpl+"))
292 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
293 return export_unused_gpl;
294 else if (strstarts(secname, "___ksymtab_gpl_future+"))
295 return export_gpl_future;
297 return export_unknown;
300 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
302 if (sec == elf->export_sec)
304 else if (sec == elf->export_unused_sec)
305 return export_unused;
306 else if (sec == elf->export_gpl_sec)
308 else if (sec == elf->export_unused_gpl_sec)
309 return export_unused_gpl;
310 else if (sec == elf->export_gpl_future_sec)
311 return export_gpl_future;
313 return export_unknown;
317 * Add an exported symbol - it may have already been added without a
318 * CRC, in this case just update the CRC
320 static struct symbol *sym_add_exported(const char *name, struct module *mod,
323 struct symbol *s = find_symbol(name);
326 s = new_symbol(name, mod, export);
329 warn("%s: '%s' exported twice. Previous export "
330 "was in %s%s\n", mod->name, name,
332 is_vmlinux(s->module->name) ?"":".ko");
334 /* In case Module.symvers was out of date */
339 s->vmlinux = is_vmlinux(mod->name);
345 static void sym_update_crc(const char *name, struct module *mod,
346 unsigned int crc, enum export export)
348 struct symbol *s = find_symbol(name);
351 s = new_symbol(name, mod, export);
352 /* Don't complain when we find it later. */
359 void *grab_file(const char *filename, unsigned long *size)
362 void *map = MAP_FAILED;
365 fd = open(filename, O_RDONLY);
372 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
376 if (map == MAP_FAILED)
382 * Return a copy of the next line in a mmap'ed file.
383 * spaces in the beginning of the line is trimmed away.
384 * Return a pointer to a static buffer.
386 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
388 static char line[4096];
391 signed char *p = (signed char *)file + *pos;
394 for (; *pos < size ; (*pos)++) {
395 if (skip && isspace(*p)) {
400 if (*p != '\n' && (*pos < size)) {
404 break; /* Too long, stop */
415 void release_file(void *file, unsigned long size)
420 static int parse_elf(struct elf_info *info, const char *filename)
426 const char *secstrings;
427 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
429 hdr = grab_file(filename, &info->size);
431 if (ignore_missing_files) {
432 fprintf(stderr, "%s: %s (ignored)\n", filename,
440 if (info->size < sizeof(*hdr)) {
441 /* file too small, assume this is an empty .o file */
444 /* Is this a valid ELF file? */
445 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
446 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
447 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
448 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
449 /* Not an ELF file - silently ignore it */
452 /* Fix endianness in ELF header */
453 hdr->e_type = TO_NATIVE(hdr->e_type);
454 hdr->e_machine = TO_NATIVE(hdr->e_machine);
455 hdr->e_version = TO_NATIVE(hdr->e_version);
456 hdr->e_entry = TO_NATIVE(hdr->e_entry);
457 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
458 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
459 hdr->e_flags = TO_NATIVE(hdr->e_flags);
460 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
461 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
462 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
463 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
464 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
465 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
466 sechdrs = (void *)hdr + hdr->e_shoff;
467 info->sechdrs = sechdrs;
469 /* Check if file offset is correct */
470 if (hdr->e_shoff > info->size) {
471 fatal("section header offset=%lu in file '%s' is bigger than "
472 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
473 filename, info->size);
477 if (hdr->e_shnum == SHN_UNDEF) {
479 * There are more than 64k sections,
480 * read count from .sh_size.
482 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
485 info->num_sections = hdr->e_shnum;
487 if (hdr->e_shstrndx == SHN_XINDEX) {
488 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
491 info->secindex_strings = hdr->e_shstrndx;
494 /* Fix endianness in section headers */
495 for (i = 0; i < info->num_sections; i++) {
496 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
497 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
498 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
499 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
500 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
501 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
502 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
503 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
504 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
505 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
507 /* Find symbol table. */
508 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
509 for (i = 1; i < info->num_sections; i++) {
511 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
513 if (!nobits && sechdrs[i].sh_offset > info->size) {
514 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
515 "sizeof(*hrd)=%zu\n", filename,
516 (unsigned long)sechdrs[i].sh_offset,
520 secname = secstrings + sechdrs[i].sh_name;
521 if (strcmp(secname, ".modinfo") == 0) {
523 fatal("%s has NOBITS .modinfo\n", filename);
524 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
525 info->modinfo_len = sechdrs[i].sh_size;
526 } else if (strcmp(secname, "__ksymtab") == 0)
527 info->export_sec = i;
528 else if (strcmp(secname, "__ksymtab_unused") == 0)
529 info->export_unused_sec = i;
530 else if (strcmp(secname, "__ksymtab_gpl") == 0)
531 info->export_gpl_sec = i;
532 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
533 info->export_unused_gpl_sec = i;
534 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
535 info->export_gpl_future_sec = i;
537 if (sechdrs[i].sh_type == SHT_SYMTAB) {
538 unsigned int sh_link_idx;
540 info->symtab_start = (void *)hdr +
541 sechdrs[i].sh_offset;
542 info->symtab_stop = (void *)hdr +
543 sechdrs[i].sh_offset + sechdrs[i].sh_size;
544 sh_link_idx = sechdrs[i].sh_link;
545 info->strtab = (void *)hdr +
546 sechdrs[sh_link_idx].sh_offset;
549 /* 32bit section no. table? ("more than 64k sections") */
550 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
551 symtab_shndx_idx = i;
552 info->symtab_shndx_start = (void *)hdr +
553 sechdrs[i].sh_offset;
554 info->symtab_shndx_stop = (void *)hdr +
555 sechdrs[i].sh_offset + sechdrs[i].sh_size;
558 if (!info->symtab_start)
559 fatal("%s has no symtab?\n", filename);
561 /* Fix endianness in symbols */
562 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
563 sym->st_shndx = TO_NATIVE(sym->st_shndx);
564 sym->st_name = TO_NATIVE(sym->st_name);
565 sym->st_value = TO_NATIVE(sym->st_value);
566 sym->st_size = TO_NATIVE(sym->st_size);
569 if (symtab_shndx_idx != ~0U) {
571 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
572 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
573 filename, sechdrs[symtab_shndx_idx].sh_link,
576 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
584 static void parse_elf_finish(struct elf_info *info)
586 release_file(info->hdr, info->size);
589 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
591 /* ignore __this_module, it will be resolved shortly */
592 if (strcmp(symname, "__this_module") == 0)
594 /* ignore global offset table */
595 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
597 if (info->hdr->e_machine == EM_PPC)
598 /* Special register function linked on all modules during final link of .ko */
599 if (strstarts(symname, "_restgpr_") ||
600 strstarts(symname, "_savegpr_") ||
601 strstarts(symname, "_rest32gpr_") ||
602 strstarts(symname, "_save32gpr_") ||
603 strstarts(symname, "_restvr_") ||
604 strstarts(symname, "_savevr_"))
606 if (info->hdr->e_machine == EM_PPC64)
607 /* Special register function linked on all modules during final link of .ko */
608 if (strstarts(symname, "_restgpr0_") ||
609 strstarts(symname, "_savegpr0_") ||
610 strstarts(symname, "_restvr_") ||
611 strstarts(symname, "_savevr_") ||
612 strcmp(symname, ".TOC.") == 0)
614 /* Do not ignore this symbol */
618 static void handle_modversions(struct module *mod, struct elf_info *info,
619 Elf_Sym *sym, const char *symname)
625 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
626 strstarts(symname, "__ksymtab"))
627 export = export_from_secname(info, get_secindex(info, sym));
629 export = export_from_sec(info, get_secindex(info, sym));
632 if (strstarts(symname, "__crc_")) {
634 crc = (unsigned int) sym->st_value;
635 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
638 /* symbol points to the CRC in the ELF object */
639 crcp = (void *)info->hdr + sym->st_value +
640 info->sechdrs[sym->st_shndx].sh_offset -
641 (info->hdr->e_type != ET_REL ?
642 info->sechdrs[sym->st_shndx].sh_addr : 0);
643 crc = TO_NATIVE(*crcp);
645 sym_update_crc(symname + strlen("__crc_"), mod, crc,
649 switch (sym->st_shndx) {
651 if (strstarts(symname, "__gnu_lto_")) {
652 /* Should warn here, but modpost runs before the linker */
654 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
657 /* undefined symbol */
658 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
659 ELF_ST_BIND(sym->st_info) != STB_WEAK)
661 if (ignore_undef_symbol(info, symname))
663 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
664 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
665 /* add compatibility with older glibc */
666 #ifndef STT_SPARC_REGISTER
667 #define STT_SPARC_REGISTER STT_REGISTER
669 if (info->hdr->e_machine == EM_SPARC ||
670 info->hdr->e_machine == EM_SPARCV9) {
671 /* Ignore register directives. */
672 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
674 if (symname[0] == '.') {
675 char *munged = NOFAIL(strdup(symname));
677 munged[1] = toupper(munged[1]);
684 const char *e = is_vmlinux(mod->name) ?"":".ko";
685 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
686 symname + strlen("__crc_"), mod->name, e);
688 mod->unres = alloc_symbol(symname,
689 ELF_ST_BIND(sym->st_info) == STB_WEAK,
693 /* All exported symbols */
694 if (strstarts(symname, "__ksymtab_")) {
695 sym_add_exported(symname + strlen("__ksymtab_"), mod,
698 if (strcmp(symname, "init_module") == 0)
700 if (strcmp(symname, "cleanup_module") == 0)
701 mod->has_cleanup = 1;
707 * Parse tag=value strings from .modinfo section
709 static char *next_string(char *string, unsigned long *secsize)
711 /* Skip non-zero chars */
714 if ((*secsize)-- <= 1)
718 /* Skip any zero padding. */
721 if ((*secsize)-- <= 1)
727 static char *get_next_modinfo(struct elf_info *info, const char *tag,
731 unsigned int taglen = strlen(tag);
732 char *modinfo = info->modinfo;
733 unsigned long size = info->modinfo_len;
736 size -= prev - modinfo;
737 modinfo = next_string(prev, &size);
740 for (p = modinfo; p; p = next_string(p, &size)) {
741 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
742 return p + taglen + 1;
747 static char *get_modinfo(struct elf_info *info, const char *tag)
750 return get_next_modinfo(info, tag, NULL);
754 * Test if string s ends in string sub
757 static int strrcmp(const char *s, const char *sub)
765 sublen = strlen(sub);
767 if ((slen == 0) || (sublen == 0))
773 return memcmp(s + slen - sublen, sub, sublen);
776 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
779 return elf->strtab + sym->st_name;
784 /* The pattern is an array of simple patterns.
785 * "foo" will match an exact string equal to "foo"
786 * "*foo" will match a string that ends with "foo"
787 * "foo*" will match a string that begins with "foo"
788 * "*foo*" will match a string that contains "foo"
790 static int match(const char *sym, const char * const pat[])
795 const char *endp = p + strlen(p) - 1;
798 if (*p == '*' && *endp == '*') {
799 char *here, *bare = strndup(p + 1, strlen(p) - 2);
801 here = strstr(sym, bare);
807 else if (*p == '*') {
808 if (strrcmp(sym, p + 1) == 0)
812 else if (*endp == '*') {
813 if (strncmp(sym, p, strlen(p) - 1) == 0)
818 if (strcmp(p, sym) == 0)
826 /* sections that we do not want to do full section mismatch check on */
827 static const char *const section_white_list[] =
831 ".cranges", /* sh64 */
832 ".zdebug*", /* Compressed debug sections. */
833 ".GCC.command.line", /* record-gcc-switches */
834 ".mdebug*", /* alpha, score, mips etc. */
835 ".pdr", /* alpha, score, mips etc. */
840 ".xt.prop", /* xtensa */
841 ".xt.lit", /* xtensa */
842 ".arcextmap*", /* arc */
843 ".gnu.linkonce.arcext*", /* arc : modules */
844 ".cmem*", /* EZchip */
845 ".fmt_slot*", /* EZchip */
852 * This is used to find sections missing the SHF_ALLOC flag.
853 * The cause of this is often a section specified in assembler
854 * without "ax" / "aw".
856 static void check_section(const char *modname, struct elf_info *elf,
859 const char *sec = sech_name(elf, sechdr);
861 if (sechdr->sh_type == SHT_PROGBITS &&
862 !(sechdr->sh_flags & SHF_ALLOC) &&
863 !match(sec, section_white_list)) {
864 warn("%s (%s): unexpected non-allocatable section.\n"
865 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
866 "Note that for example <linux/init.h> contains\n"
867 "section definitions for use in .S files.\n\n",
874 #define ALL_INIT_DATA_SECTIONS \
875 ".init.setup", ".init.rodata", ".meminit.rodata", \
876 ".init.data", ".meminit.data"
877 #define ALL_EXIT_DATA_SECTIONS \
878 ".exit.data", ".memexit.data"
880 #define ALL_INIT_TEXT_SECTIONS \
881 ".init.text", ".meminit.text"
882 #define ALL_EXIT_TEXT_SECTIONS \
883 ".exit.text", ".memexit.text"
885 #define ALL_PCI_INIT_SECTIONS \
886 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
887 ".pci_fixup_enable", ".pci_fixup_resume", \
888 ".pci_fixup_resume_early", ".pci_fixup_suspend"
890 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
891 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
893 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
894 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
896 #define DATA_SECTIONS ".data", ".data.rel"
897 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
898 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
899 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
900 ".fixup", ".entry.text", ".exception.text", ".text.*", \
903 #define INIT_SECTIONS ".init.*"
904 #define MEM_INIT_SECTIONS ".meminit.*"
906 #define EXIT_SECTIONS ".exit.*"
907 #define MEM_EXIT_SECTIONS ".memexit.*"
909 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
910 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
912 /* init data sections */
913 static const char *const init_data_sections[] =
914 { ALL_INIT_DATA_SECTIONS, NULL };
916 /* all init sections */
917 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
919 /* All init and exit sections (code + data) */
920 static const char *const init_exit_sections[] =
921 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
923 /* all text sections */
924 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
927 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
930 /* symbols in .data that may refer to init/exit sections */
931 #define DEFAULT_SYMBOL_WHITE_LIST \
933 "*_template", /* scsi uses *_template a lot */ \
934 "*_timer", /* arm uses ops structures named _timer a lot */ \
935 "*_sht", /* scsi also used *_sht to some extent */ \
941 static const char *const head_sections[] = { ".head.text*", NULL };
942 static const char *const linker_symbols[] =
943 { "__init_begin", "_sinittext", "_einittext", NULL };
944 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
951 XXXINIT_TO_SOME_INIT,
952 XXXEXIT_TO_SOME_EXIT,
953 ANY_INIT_TO_ANY_EXIT,
954 ANY_EXIT_TO_ANY_INIT,
960 * Describe how to match sections on different criterias:
962 * @fromsec: Array of sections to be matched.
964 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
965 * this array is forbidden (black-list). Can be empty.
967 * @good_tosec: Relocations applied to a section in @fromsec must be
968 * targetting sections in this array (white-list). Can be empty.
970 * @mismatch: Type of mismatch.
972 * @symbol_white_list: Do not match a relocation to a symbol in this list
973 * even if it is targetting a section in @bad_to_sec.
975 * @handler: Specific handler to call when a match is found. If NULL,
976 * default_mismatch_handler() will be called.
979 struct sectioncheck {
980 const char *fromsec[20];
981 const char *bad_tosec[20];
982 const char *good_tosec[20];
983 enum mismatch mismatch;
984 const char *symbol_white_list[20];
985 void (*handler)(const char *modname, struct elf_info *elf,
986 const struct sectioncheck* const mismatch,
987 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
991 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
992 const struct sectioncheck* const mismatch,
993 Elf_Rela *r, Elf_Sym *sym,
994 const char *fromsec);
996 static const struct sectioncheck sectioncheck[] = {
997 /* Do not reference init/exit code/data from
998 * normal code and data
1001 .fromsec = { TEXT_SECTIONS, NULL },
1002 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1003 .mismatch = TEXT_TO_ANY_INIT,
1004 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1007 .fromsec = { DATA_SECTIONS, NULL },
1008 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1009 .mismatch = DATA_TO_ANY_INIT,
1010 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1013 .fromsec = { DATA_SECTIONS, NULL },
1014 .bad_tosec = { INIT_SECTIONS, NULL },
1015 .mismatch = DATA_TO_ANY_INIT,
1016 .symbol_white_list = {
1017 "*_template", "*_timer", "*_sht", "*_ops",
1018 "*_probe", "*_probe_one", "*_console", NULL
1022 .fromsec = { TEXT_SECTIONS, NULL },
1023 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1024 .mismatch = TEXT_TO_ANY_EXIT,
1025 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1028 .fromsec = { DATA_SECTIONS, NULL },
1029 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1030 .mismatch = DATA_TO_ANY_EXIT,
1031 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1033 /* Do not reference init code/data from meminit code/data */
1035 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1036 .bad_tosec = { INIT_SECTIONS, NULL },
1037 .mismatch = XXXINIT_TO_SOME_INIT,
1038 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1040 /* Do not reference exit code/data from memexit code/data */
1042 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1043 .bad_tosec = { EXIT_SECTIONS, NULL },
1044 .mismatch = XXXEXIT_TO_SOME_EXIT,
1045 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1047 /* Do not use exit code/data from init code */
1049 .fromsec = { ALL_INIT_SECTIONS, NULL },
1050 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1051 .mismatch = ANY_INIT_TO_ANY_EXIT,
1052 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1054 /* Do not use init code/data from exit code */
1056 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1057 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1058 .mismatch = ANY_EXIT_TO_ANY_INIT,
1059 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1062 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1063 .bad_tosec = { INIT_SECTIONS, NULL },
1064 .mismatch = ANY_INIT_TO_ANY_EXIT,
1065 .symbol_white_list = { NULL },
1067 /* Do not export init/exit functions or data */
1069 .fromsec = { "___ksymtab*", NULL },
1070 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1071 .mismatch = EXPORT_TO_INIT_EXIT,
1072 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1075 .fromsec = { "__ex_table", NULL },
1076 /* If you're adding any new black-listed sections in here, consider
1077 * adding a special 'printer' for them in scripts/check_extable.
1079 .bad_tosec = { ".altinstr_replacement", NULL },
1080 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1081 .mismatch = EXTABLE_TO_NON_TEXT,
1082 .handler = extable_mismatch_handler,
1086 static const struct sectioncheck *section_mismatch(
1087 const char *fromsec, const char *tosec)
1090 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1091 const struct sectioncheck *check = §ioncheck[0];
1094 * The target section could be the SHT_NUL section when we're
1095 * handling relocations to un-resolved symbols, trying to match it
1096 * doesn't make much sense and causes build failures on parisc
1102 for (i = 0; i < elems; i++) {
1103 if (match(fromsec, check->fromsec)) {
1104 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1106 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1115 * Whitelist to allow certain references to pass with no warning.
1118 * If a module parameter is declared __initdata and permissions=0
1119 * then this is legal despite the warning generated.
1120 * We cannot see value of permissions here, so just ignore
1122 * The pattern is identified by:
1123 * tosec = .init.data
1128 * module_param_call() ops can refer to __init set function if permissions=0
1129 * The pattern is identified by:
1130 * tosec = .init.text
1132 * atsym = __param_ops_*
1135 * Many drivers utilise a *driver container with references to
1136 * add, remove, probe functions etc.
1137 * the pattern is identified by:
1138 * tosec = init or exit section
1139 * fromsec = data section
1140 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1141 * *probe_one, *_console, *_timer
1144 * Whitelist all references from .head.text to any init section
1147 * Some symbols belong to init section but still it is ok to reference
1148 * these from non-init sections as these symbols don't have any memory
1149 * allocated for them and symbol address and value are same. So even
1150 * if init section is freed, its ok to reference those symbols.
1151 * For ex. symbols marking the init section boundaries.
1152 * This pattern is identified by
1153 * refsymname = __init_begin, _sinittext, _einittext
1156 * GCC may optimize static inlines when fed constant arg(s) resulting
1157 * in functions like cpumask_empty() -- generating an associated symbol
1158 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1159 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1160 * meaningless section warning. May need to add isra symbols too...
1161 * This pattern is identified by
1162 * tosec = init section
1163 * fromsec = text section
1164 * refsymname = *.constprop.*
1167 * Hide section mismatch warnings for ELF local symbols. The goal
1168 * is to eliminate false positive modpost warnings caused by
1169 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1170 * Autogenerated symbol names bypass modpost's "Pattern 2"
1171 * whitelisting, which relies on pattern-matching against symbol
1172 * names to work. (One situation where gcc can autogenerate ELF
1173 * local symbols is when "-fsection-anchors" is used.)
1175 static int secref_whitelist(const struct sectioncheck *mismatch,
1176 const char *fromsec, const char *fromsym,
1177 const char *tosec, const char *tosym)
1179 /* Check for pattern 1 */
1180 if (match(tosec, init_data_sections) &&
1181 match(fromsec, data_sections) &&
1182 strstarts(fromsym, "__param"))
1185 /* Check for pattern 1a */
1186 if (strcmp(tosec, ".init.text") == 0 &&
1187 match(fromsec, data_sections) &&
1188 strstarts(fromsym, "__param_ops_"))
1191 /* Check for pattern 2 */
1192 if (match(tosec, init_exit_sections) &&
1193 match(fromsec, data_sections) &&
1194 match(fromsym, mismatch->symbol_white_list))
1197 /* Check for pattern 3 */
1198 if (match(fromsec, head_sections) &&
1199 match(tosec, init_sections))
1202 /* Check for pattern 4 */
1203 if (match(tosym, linker_symbols))
1206 /* Check for pattern 5 */
1207 if (match(fromsec, text_sections) &&
1208 match(tosec, init_sections) &&
1209 match(fromsym, optim_symbols))
1212 /* Check for pattern 6 */
1213 if (strstarts(fromsym, ".L"))
1219 static inline int is_arm_mapping_symbol(const char *str)
1221 return str[0] == '$' &&
1222 (str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x')
1223 && (str[2] == '\0' || str[2] == '.');
1227 * If there's no name there, ignore it; likewise, ignore it if it's
1228 * one of the magic symbols emitted used by current ARM tools.
1230 * Otherwise if find_symbols_between() returns those symbols, they'll
1231 * fail the whitelist tests and cause lots of false alarms ... fixable
1232 * only by merging __exit and __init sections into __text, bloating
1233 * the kernel (which is especially evil on embedded platforms).
1235 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1237 const char *name = elf->strtab + sym->st_name;
1239 if (!name || !strlen(name))
1241 return !is_arm_mapping_symbol(name);
1245 * Find symbol based on relocation record info.
1246 * In some cases the symbol supplied is a valid symbol so
1247 * return refsym. If st_name != 0 we assume this is a valid symbol.
1248 * In other cases the symbol needs to be looked up in the symbol table
1249 * based on section and address.
1251 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1255 Elf_Sym *near = NULL;
1256 Elf64_Sword distance = 20;
1258 unsigned int relsym_secindex;
1260 if (relsym->st_name != 0)
1263 relsym_secindex = get_secindex(elf, relsym);
1264 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1265 if (get_secindex(elf, sym) != relsym_secindex)
1267 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1269 if (!is_valid_name(elf, sym))
1271 if (sym->st_value == addr)
1273 /* Find a symbol nearby - addr are maybe negative */
1274 d = sym->st_value - addr;
1276 d = addr - sym->st_value;
1282 /* We need a close match */
1290 * Find symbols before or equal addr and after addr - in the section sec.
1291 * If we find two symbols with equal offset prefer one with a valid name.
1292 * The ELF format may have a better way to detect what type of symbol
1293 * it is, but this works for now.
1295 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1299 Elf_Sym *near = NULL;
1300 Elf_Addr distance = ~0;
1302 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1305 if (is_shndx_special(sym->st_shndx))
1307 symsec = sec_name(elf, get_secindex(elf, sym));
1308 if (strcmp(symsec, sec) != 0)
1310 if (!is_valid_name(elf, sym))
1312 if (sym->st_value <= addr) {
1313 if ((addr - sym->st_value) < distance) {
1314 distance = addr - sym->st_value;
1316 } else if ((addr - sym->st_value) == distance) {
1325 * Convert a section name to the function/data attribute
1326 * .init.text => __init
1327 * .memexitconst => __memconst
1330 * The memory of returned value has been allocated on a heap. The user of this
1331 * method should free it after usage.
1333 static char *sec2annotation(const char *s)
1335 if (match(s, init_exit_sections)) {
1336 char *p = NOFAIL(malloc(20));
1343 while (*s && *s != '.')
1348 if (strstr(s, "rodata") != NULL)
1349 strcat(p, "const ");
1350 else if (strstr(s, "data") != NULL)
1356 return NOFAIL(strdup(""));
1360 static int is_function(Elf_Sym *sym)
1363 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1368 static void print_section_list(const char * const list[20])
1370 const char *const *s = list;
1373 fprintf(stderr, "%s", *s);
1376 fprintf(stderr, ", ");
1378 fprintf(stderr, "\n");
1381 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1384 case 0: *name = "variable"; *name_p = ""; break;
1385 case 1: *name = "function"; *name_p = "()"; break;
1386 default: *name = "(unknown reference)"; *name_p = ""; break;
1391 * Print a warning about a section mismatch.
1392 * Try to find symbols near it so user can find it.
1393 * Check whitelist before warning - it may be a false positive.
1395 static void report_sec_mismatch(const char *modname,
1396 const struct sectioncheck *mismatch,
1397 const char *fromsec,
1398 unsigned long long fromaddr,
1399 const char *fromsym,
1401 const char *tosec, const char *tosym,
1404 const char *from, *from_p;
1405 const char *to, *to_p;
1409 sec_mismatch_count++;
1410 if (!sec_mismatch_verbose)
1413 get_pretty_name(from_is_func, &from, &from_p);
1414 get_pretty_name(to_is_func, &to, &to_p);
1416 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1417 "to the %s %s:%s%s\n",
1418 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1421 switch (mismatch->mismatch) {
1422 case TEXT_TO_ANY_INIT:
1423 prl_from = sec2annotation(fromsec);
1424 prl_to = sec2annotation(tosec);
1426 "The function %s%s() references\n"
1428 "This is often because %s lacks a %s\n"
1429 "annotation or the annotation of %s is wrong.\n",
1431 to, prl_to, tosym, to_p,
1432 fromsym, prl_to, tosym);
1436 case DATA_TO_ANY_INIT: {
1437 prl_to = sec2annotation(tosec);
1439 "The variable %s references\n"
1441 "If the reference is valid then annotate the\n"
1442 "variable with __init* or __refdata (see linux/init.h) "
1443 "or name the variable:\n",
1444 fromsym, to, prl_to, tosym, to_p);
1445 print_section_list(mismatch->symbol_white_list);
1449 case TEXT_TO_ANY_EXIT:
1450 prl_to = sec2annotation(tosec);
1452 "The function %s() references a %s in an exit section.\n"
1453 "Often the %s %s%s has valid usage outside the exit section\n"
1454 "and the fix is to remove the %sannotation of %s.\n",
1455 fromsym, to, to, tosym, to_p, prl_to, tosym);
1458 case DATA_TO_ANY_EXIT: {
1459 prl_to = sec2annotation(tosec);
1461 "The variable %s references\n"
1463 "If the reference is valid then annotate the\n"
1464 "variable with __exit* (see linux/init.h) or "
1465 "name the variable:\n",
1466 fromsym, to, prl_to, tosym, to_p);
1467 print_section_list(mismatch->symbol_white_list);
1471 case XXXINIT_TO_SOME_INIT:
1472 case XXXEXIT_TO_SOME_EXIT:
1473 prl_from = sec2annotation(fromsec);
1474 prl_to = sec2annotation(tosec);
1476 "The %s %s%s%s references\n"
1478 "If %s is only used by %s then\n"
1479 "annotate %s with a matching annotation.\n",
1480 from, prl_from, fromsym, from_p,
1481 to, prl_to, tosym, to_p,
1482 tosym, fromsym, tosym);
1486 case ANY_INIT_TO_ANY_EXIT:
1487 prl_from = sec2annotation(fromsec);
1488 prl_to = sec2annotation(tosec);
1490 "The %s %s%s%s references\n"
1492 "This is often seen when error handling "
1493 "in the init function\n"
1494 "uses functionality in the exit path.\n"
1495 "The fix is often to remove the %sannotation of\n"
1496 "%s%s so it may be used outside an exit section.\n",
1497 from, prl_from, fromsym, from_p,
1498 to, prl_to, tosym, to_p,
1499 prl_to, tosym, to_p);
1503 case ANY_EXIT_TO_ANY_INIT:
1504 prl_from = sec2annotation(fromsec);
1505 prl_to = sec2annotation(tosec);
1507 "The %s %s%s%s references\n"
1509 "This is often seen when error handling "
1510 "in the exit function\n"
1511 "uses functionality in the init path.\n"
1512 "The fix is often to remove the %sannotation of\n"
1513 "%s%s so it may be used outside an init section.\n",
1514 from, prl_from, fromsym, from_p,
1515 to, prl_to, tosym, to_p,
1516 prl_to, tosym, to_p);
1520 case EXPORT_TO_INIT_EXIT:
1521 prl_to = sec2annotation(tosec);
1523 "The symbol %s is exported and annotated %s\n"
1524 "Fix this by removing the %sannotation of %s "
1525 "or drop the export.\n",
1526 tosym, prl_to, prl_to, tosym);
1529 case EXTABLE_TO_NON_TEXT:
1530 fatal("There's a special handler for this mismatch type, "
1531 "we should never get here.");
1534 fprintf(stderr, "\n");
1537 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1538 const struct sectioncheck* const mismatch,
1539 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1545 const char *fromsym;
1547 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1548 fromsym = sym_name(elf, from);
1550 if (strstarts(fromsym, "reference___initcall"))
1553 tosec = sec_name(elf, get_secindex(elf, sym));
1554 to = find_elf_symbol(elf, r->r_addend, sym);
1555 tosym = sym_name(elf, to);
1557 /* check whitelist - we may ignore it */
1558 if (secref_whitelist(mismatch,
1559 fromsec, fromsym, tosec, tosym)) {
1560 report_sec_mismatch(modname, mismatch,
1561 fromsec, r->r_offset, fromsym,
1562 is_function(from), tosec, tosym,
1567 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1569 if (section_index > elf->num_sections)
1570 fatal("section_index is outside elf->num_sections!\n");
1572 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1576 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1577 * to know the sizeof(struct exception_table_entry) for the target architecture.
1579 static unsigned int extable_entry_size = 0;
1580 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1583 * If we're currently checking the second relocation within __ex_table,
1584 * that relocation offset tells us the offsetof(struct
1585 * exception_table_entry, fixup) which is equal to sizeof(struct
1586 * exception_table_entry) divided by two. We use that to our advantage
1587 * since there's no portable way to get that size as every architecture
1588 * seems to go with different sized types. Not pretty but better than
1589 * hard-coding the size for every architecture..
1591 if (!extable_entry_size)
1592 extable_entry_size = r->r_offset * 2;
1595 static inline bool is_extable_fault_address(Elf_Rela *r)
1598 * extable_entry_size is only discovered after we've handled the
1599 * _second_ relocation in __ex_table, so only abort when we're not
1600 * handling the first reloc and extable_entry_size is zero.
1602 if (r->r_offset && extable_entry_size == 0)
1603 fatal("extable_entry size hasn't been discovered!\n");
1605 return ((r->r_offset == 0) ||
1606 (r->r_offset % extable_entry_size == 0));
1609 #define is_second_extable_reloc(Start, Cur, Sec) \
1610 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1612 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1613 const struct sectioncheck* const mismatch,
1614 Elf_Rela* r, Elf_Sym* sym,
1615 const char* fromsec, const char* tosec)
1617 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1618 const char* fromsym_name = sym_name(elf, fromsym);
1619 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1620 const char* tosym_name = sym_name(elf, tosym);
1621 const char* from_pretty_name;
1622 const char* from_pretty_name_p;
1623 const char* to_pretty_name;
1624 const char* to_pretty_name_p;
1626 get_pretty_name(is_function(fromsym),
1627 &from_pretty_name, &from_pretty_name_p);
1628 get_pretty_name(is_function(tosym),
1629 &to_pretty_name, &to_pretty_name_p);
1631 warn("%s(%s+0x%lx): Section mismatch in reference"
1632 " from the %s %s%s to the %s %s:%s%s\n",
1633 modname, fromsec, (long)r->r_offset, from_pretty_name,
1634 fromsym_name, from_pretty_name_p,
1635 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1637 if (!match(tosec, mismatch->bad_tosec) &&
1638 is_executable_section(elf, get_secindex(elf, sym)))
1640 "The relocation at %s+0x%lx references\n"
1641 "section \"%s\" which is not in the list of\n"
1642 "authorized sections. If you're adding a new section\n"
1643 "and/or if this reference is valid, add \"%s\" to the\n"
1644 "list of authorized sections to jump to on fault.\n"
1645 "This can be achieved by adding \"%s\" to \n"
1646 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1647 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1650 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1651 const struct sectioncheck* const mismatch,
1652 Elf_Rela* r, Elf_Sym* sym,
1653 const char *fromsec)
1655 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1657 sec_mismatch_count++;
1659 if (sec_mismatch_verbose)
1660 report_extable_warnings(modname, elf, mismatch, r, sym,
1663 if (match(tosec, mismatch->bad_tosec))
1664 fatal("The relocation at %s+0x%lx references\n"
1665 "section \"%s\" which is black-listed.\n"
1666 "Something is seriously wrong and should be fixed.\n"
1667 "You might get more information about where this is\n"
1668 "coming from by using scripts/check_extable.sh %s\n",
1669 fromsec, (long)r->r_offset, tosec, modname);
1670 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1671 if (is_extable_fault_address(r))
1672 fatal("The relocation at %s+0x%lx references\n"
1673 "section \"%s\" which is not executable, IOW\n"
1674 "it is not possible for the kernel to fault\n"
1675 "at that address. Something is seriously wrong\n"
1676 "and should be fixed.\n",
1677 fromsec, (long)r->r_offset, tosec);
1679 fatal("The relocation at %s+0x%lx references\n"
1680 "section \"%s\" which is not executable, IOW\n"
1681 "the kernel will fault if it ever tries to\n"
1682 "jump to it. Something is seriously wrong\n"
1683 "and should be fixed.\n",
1684 fromsec, (long)r->r_offset, tosec);
1688 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1689 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1691 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1692 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1695 if (mismatch->handler)
1696 mismatch->handler(modname, elf, mismatch,
1699 default_mismatch_handler(modname, elf, mismatch,
1704 static unsigned int *reloc_location(struct elf_info *elf,
1705 Elf_Shdr *sechdr, Elf_Rela *r)
1707 Elf_Shdr *sechdrs = elf->sechdrs;
1708 int section = sechdr->sh_info;
1710 return (void *)elf->hdr + sechdrs[section].sh_offset +
1714 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1716 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1717 unsigned int *location = reloc_location(elf, sechdr, r);
1721 r->r_addend = TO_NATIVE(*location);
1724 r->r_addend = TO_NATIVE(*location) + 4;
1725 /* For CONFIG_RELOCATABLE=y */
1726 if (elf->hdr->e_type == ET_EXEC)
1727 r->r_addend += r->r_offset;
1734 #define R_ARM_CALL 28
1736 #ifndef R_ARM_JUMP24
1737 #define R_ARM_JUMP24 29
1740 #ifndef R_ARM_THM_CALL
1741 #define R_ARM_THM_CALL 10
1743 #ifndef R_ARM_THM_JUMP24
1744 #define R_ARM_THM_JUMP24 30
1746 #ifndef R_ARM_THM_JUMP19
1747 #define R_ARM_THM_JUMP19 51
1750 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1752 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1756 /* From ARM ABI: (S + A) | T */
1757 r->r_addend = (int)(long)
1758 (elf->symtab_start + ELF_R_SYM(r->r_info));
1763 case R_ARM_THM_CALL:
1764 case R_ARM_THM_JUMP24:
1765 case R_ARM_THM_JUMP19:
1766 /* From ARM ABI: ((S + A) | T) - P */
1767 r->r_addend = (int)(long)(elf->hdr +
1769 (r->r_offset - sechdr->sh_addr));
1777 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1779 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1780 unsigned int *location = reloc_location(elf, sechdr, r);
1783 if (r_typ == R_MIPS_HI16)
1784 return 1; /* skip this */
1785 inst = TO_NATIVE(*location);
1788 r->r_addend = inst & 0xffff;
1791 r->r_addend = (inst & 0x03ffffff) << 2;
1800 static void section_rela(const char *modname, struct elf_info *elf,
1807 const char *fromsec;
1809 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1810 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1812 fromsec = sech_name(elf, sechdr);
1813 fromsec += strlen(".rela");
1814 /* if from section (name) is know good then skip it */
1815 if (match(fromsec, section_white_list))
1818 for (rela = start; rela < stop; rela++) {
1819 r.r_offset = TO_NATIVE(rela->r_offset);
1820 #if KERNEL_ELFCLASS == ELFCLASS64
1821 if (elf->hdr->e_machine == EM_MIPS) {
1823 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1824 r_sym = TO_NATIVE(r_sym);
1825 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1826 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1828 r.r_info = TO_NATIVE(rela->r_info);
1829 r_sym = ELF_R_SYM(r.r_info);
1832 r.r_info = TO_NATIVE(rela->r_info);
1833 r_sym = ELF_R_SYM(r.r_info);
1835 r.r_addend = TO_NATIVE(rela->r_addend);
1836 sym = elf->symtab_start + r_sym;
1837 /* Skip special sections */
1838 if (is_shndx_special(sym->st_shndx))
1840 if (is_second_extable_reloc(start, rela, fromsec))
1841 find_extable_entry_size(fromsec, &r);
1842 check_section_mismatch(modname, elf, &r, sym, fromsec);
1846 static void section_rel(const char *modname, struct elf_info *elf,
1853 const char *fromsec;
1855 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1856 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1858 fromsec = sech_name(elf, sechdr);
1859 fromsec += strlen(".rel");
1860 /* if from section (name) is know good then skip it */
1861 if (match(fromsec, section_white_list))
1864 for (rel = start; rel < stop; rel++) {
1865 r.r_offset = TO_NATIVE(rel->r_offset);
1866 #if KERNEL_ELFCLASS == ELFCLASS64
1867 if (elf->hdr->e_machine == EM_MIPS) {
1869 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1870 r_sym = TO_NATIVE(r_sym);
1871 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1872 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1874 r.r_info = TO_NATIVE(rel->r_info);
1875 r_sym = ELF_R_SYM(r.r_info);
1878 r.r_info = TO_NATIVE(rel->r_info);
1879 r_sym = ELF_R_SYM(r.r_info);
1882 switch (elf->hdr->e_machine) {
1884 if (addend_386_rel(elf, sechdr, &r))
1888 if (addend_arm_rel(elf, sechdr, &r))
1892 if (addend_mips_rel(elf, sechdr, &r))
1896 sym = elf->symtab_start + r_sym;
1897 /* Skip special sections */
1898 if (is_shndx_special(sym->st_shndx))
1900 if (is_second_extable_reloc(start, rel, fromsec))
1901 find_extable_entry_size(fromsec, &r);
1902 check_section_mismatch(modname, elf, &r, sym, fromsec);
1907 * A module includes a number of sections that are discarded
1908 * either when loaded or when used as built-in.
1909 * For loaded modules all functions marked __init and all data
1910 * marked __initdata will be discarded when the module has been initialized.
1911 * Likewise for modules used built-in the sections marked __exit
1912 * are discarded because __exit marked function are supposed to be called
1913 * only when a module is unloaded which never happens for built-in modules.
1914 * The check_sec_ref() function traverses all relocation records
1915 * to find all references to a section that reference a section that will
1916 * be discarded and warns about it.
1918 static void check_sec_ref(struct module *mod, const char *modname,
1919 struct elf_info *elf)
1922 Elf_Shdr *sechdrs = elf->sechdrs;
1924 /* Walk through all sections */
1925 for (i = 0; i < elf->num_sections; i++) {
1926 check_section(modname, elf, &elf->sechdrs[i]);
1927 /* We want to process only relocation sections and not .init */
1928 if (sechdrs[i].sh_type == SHT_RELA)
1929 section_rela(modname, elf, &elf->sechdrs[i]);
1930 else if (sechdrs[i].sh_type == SHT_REL)
1931 section_rel(modname, elf, &elf->sechdrs[i]);
1935 static char *remove_dot(char *s)
1937 size_t n = strcspn(s, ".");
1940 size_t m = strspn(s + n + 1, "0123456789");
1941 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1947 static void read_symbols(const char *modname)
1949 const char *symname;
1953 struct elf_info info = { };
1956 if (!parse_elf(&info, modname))
1959 mod = new_module(modname);
1961 /* When there's no vmlinux, don't print warnings about
1962 * unresolved symbols (since there'll be too many ;) */
1963 if (is_vmlinux(modname)) {
1968 license = get_modinfo(&info, "license");
1969 if (!license && !is_vmlinux(modname))
1970 warn("modpost: missing MODULE_LICENSE() in %s\n"
1971 "see include/linux/module.h for "
1972 "more information\n", modname);
1974 if (license_is_gpl_compatible(license))
1975 mod->gpl_compatible = 1;
1977 mod->gpl_compatible = 0;
1980 license = get_next_modinfo(&info, "license", license);
1983 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1984 symname = remove_dot(info.strtab + sym->st_name);
1986 handle_modversions(mod, &info, sym, symname);
1987 handle_moddevtable(mod, &info, sym, symname);
1989 if (!is_vmlinux(modname) || vmlinux_section_warnings)
1990 check_sec_ref(mod, modname, &info);
1992 version = get_modinfo(&info, "version");
1994 maybe_frob_rcs_version(modname, version, info.modinfo,
1995 version - (char *)info.hdr);
1996 if (version || (all_versions && !is_vmlinux(modname)))
1997 get_src_version(modname, mod->srcversion,
1998 sizeof(mod->srcversion)-1);
2000 parse_elf_finish(&info);
2002 /* Our trick to get versioning for module struct etc. - it's
2003 * never passed as an argument to an exported function, so
2004 * the automatic versioning doesn't pick it up, but it's really
2005 * important anyhow */
2007 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2010 static void read_symbols_from_files(const char *filename)
2013 char fname[PATH_MAX];
2015 if (strcmp(filename, "-") != 0) {
2016 in = fopen(filename, "r");
2018 fatal("Can't open filenames file %s: %m", filename);
2021 while (fgets(fname, PATH_MAX, in) != NULL) {
2022 if (strends(fname, "\n"))
2023 fname[strlen(fname)-1] = '\0';
2024 read_symbols(fname);
2033 /* We first write the generated file into memory using the
2034 * following helper, then compare to the file on disk and
2035 * only update the later if anything changed */
2037 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2038 const char *fmt, ...)
2045 len = vsnprintf(tmp, SZ, fmt, ap);
2046 buf_write(buf, tmp, len);
2050 void buf_write(struct buffer *buf, const char *s, int len)
2052 if (buf->size - buf->pos < len) {
2053 buf->size += len + SZ;
2054 buf->p = NOFAIL(realloc(buf->p, buf->size));
2056 strncpy(buf->p + buf->pos, s, len);
2060 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2062 const char *e = is_vmlinux(m) ?"":".ko";
2066 fatal("modpost: GPL-incompatible module %s%s "
2067 "uses GPL-only symbol '%s'\n", m, e, s);
2069 case export_unused_gpl:
2070 fatal("modpost: GPL-incompatible module %s%s "
2071 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2073 case export_gpl_future:
2074 warn("modpost: GPL-incompatible module %s%s "
2075 "uses future GPL-only symbol '%s'\n", m, e, s);
2079 case export_unknown:
2085 static void check_for_unused(enum export exp, const char *m, const char *s)
2087 const char *e = is_vmlinux(m) ?"":".ko";
2091 case export_unused_gpl:
2092 warn("modpost: module %s%s "
2093 "uses symbol '%s' marked UNUSED\n", m, e, s);
2101 static void check_exports(struct module *mod)
2103 struct symbol *s, *exp;
2105 for (s = mod->unres; s; s = s->next) {
2106 const char *basename;
2107 exp = find_symbol(s->name);
2108 if (!exp || exp->module == mod)
2110 basename = strrchr(mod->name, '/');
2114 basename = mod->name;
2115 if (!mod->gpl_compatible)
2116 check_for_gpl_usage(exp->export, basename, exp->name);
2117 check_for_unused(exp->export, basename, exp->name);
2121 static int check_modname_len(struct module *mod)
2123 const char *mod_name;
2125 mod_name = strrchr(mod->name, '/');
2126 if (mod_name == NULL)
2127 mod_name = mod->name;
2130 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2131 merror("module name is too long [%s.ko]\n", mod->name);
2139 * Header for the generated file
2141 static void add_header(struct buffer *b, struct module *mod)
2143 buf_printf(b, "#include <linux/build-salt.h>\n");
2144 buf_printf(b, "#include <linux/module.h>\n");
2145 buf_printf(b, "#include <linux/vermagic.h>\n");
2146 buf_printf(b, "#include <linux/compiler.h>\n");
2147 buf_printf(b, "\n");
2148 buf_printf(b, "BUILD_SALT;\n");
2149 buf_printf(b, "\n");
2150 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2151 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2152 buf_printf(b, "\n");
2153 buf_printf(b, "__visible struct module __this_module\n");
2154 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2155 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2157 buf_printf(b, "\t.init = init_module,\n");
2158 if (mod->has_cleanup)
2159 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2160 "\t.exit = cleanup_module,\n"
2162 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2163 buf_printf(b, "};\n");
2166 static void add_intree_flag(struct buffer *b, int is_intree)
2169 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2172 /* Cannot check for assembler */
2173 static void add_retpoline(struct buffer *b)
2175 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2176 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2177 buf_printf(b, "#endif\n");
2180 static void add_staging_flag(struct buffer *b, const char *name)
2182 if (strstarts(name, "drivers/staging"))
2183 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2187 * Record CRCs for unresolved symbols
2189 static int add_versions(struct buffer *b, struct module *mod)
2191 struct symbol *s, *exp;
2194 for (s = mod->unres; s; s = s->next) {
2195 exp = find_symbol(s->name);
2196 if (!exp || exp->module == mod) {
2197 if (have_vmlinux && !s->weak) {
2198 if (warn_unresolved) {
2199 warn("\"%s\" [%s.ko] undefined!\n",
2200 s->name, mod->name);
2202 merror("\"%s\" [%s.ko] undefined!\n",
2203 s->name, mod->name);
2209 s->module = exp->module;
2210 s->crc_valid = exp->crc_valid;
2217 buf_printf(b, "\n");
2218 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2219 buf_printf(b, "__used\n");
2220 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2222 for (s = mod->unres; s; s = s->next) {
2225 if (!s->crc_valid) {
2226 warn("\"%s\" [%s.ko] has no CRC!\n",
2227 s->name, mod->name);
2230 if (strlen(s->name) >= MODULE_NAME_LEN) {
2231 merror("too long symbol \"%s\" [%s.ko]\n",
2232 s->name, mod->name);
2236 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2240 buf_printf(b, "};\n");
2245 static void add_depends(struct buffer *b, struct module *mod,
2246 struct module *modules)
2252 for (m = modules; m; m = m->next)
2253 m->seen = is_vmlinux(m->name);
2255 buf_printf(b, "\n");
2256 buf_printf(b, "static const char __module_depends[]\n");
2257 buf_printf(b, "__used\n");
2258 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2259 buf_printf(b, "\"depends=");
2260 for (s = mod->unres; s; s = s->next) {
2265 if (s->module->seen)
2268 s->module->seen = 1;
2269 p = strrchr(s->module->name, '/');
2273 p = s->module->name;
2274 buf_printf(b, "%s%s", first ? "" : ",", p);
2277 buf_printf(b, "\";\n");
2280 static void add_srcversion(struct buffer *b, struct module *mod)
2282 if (mod->srcversion[0]) {
2283 buf_printf(b, "\n");
2284 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2289 static void write_if_changed(struct buffer *b, const char *fname)
2295 file = fopen(fname, "r");
2299 if (fstat(fileno(file), &st) < 0)
2302 if (st.st_size != b->pos)
2305 tmp = NOFAIL(malloc(b->pos));
2306 if (fread(tmp, 1, b->pos, file) != b->pos)
2309 if (memcmp(tmp, b->p, b->pos) != 0)
2321 file = fopen(fname, "w");
2326 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2333 /* parse Module.symvers file. line format:
2334 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2336 static void read_dump(const char *fname, unsigned int kernel)
2338 unsigned long size, pos = 0;
2339 void *file = grab_file(fname, &size);
2343 /* No symbol versions, silently ignore */
2346 while ((line = get_next_line(&pos, file, size))) {
2347 char *symname, *modname, *d, *export, *end;
2352 if (!(symname = strchr(line, '\t')))
2355 if (!(modname = strchr(symname, '\t')))
2358 if ((export = strchr(modname, '\t')) != NULL)
2360 if (export && ((end = strchr(export, '\t')) != NULL))
2362 crc = strtoul(line, &d, 16);
2363 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2365 mod = find_module(modname);
2367 if (is_vmlinux(modname))
2369 mod = new_module(modname);
2372 s = sym_add_exported(symname, mod, export_no(export));
2375 sym_update_crc(symname, mod, crc, export_no(export));
2377 release_file(file, size);
2380 release_file(file, size);
2381 fatal("parse error in symbol dump file\n");
2384 /* For normal builds always dump all symbols.
2385 * For external modules only dump symbols
2386 * that are not read from kernel Module.symvers.
2388 static int dump_sym(struct symbol *sym)
2390 if (!external_module)
2392 if (sym->vmlinux || sym->kernel)
2397 static void write_dump(const char *fname)
2399 struct buffer buf = { };
2400 struct symbol *symbol;
2403 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2404 symbol = symbolhash[n];
2406 if (dump_sym(symbol))
2407 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2408 symbol->crc, symbol->name,
2409 symbol->module->name,
2410 export_str(symbol->export));
2411 symbol = symbol->next;
2414 write_if_changed(&buf, fname);
2418 struct ext_sym_list {
2419 struct ext_sym_list *next;
2423 int main(int argc, char **argv)
2426 struct buffer buf = { };
2427 char *kernel_read = NULL, *module_read = NULL;
2428 char *dump_write = NULL, *files_source = NULL;
2431 struct ext_sym_list *extsym_iter;
2432 struct ext_sym_list *extsym_start = NULL;
2434 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2437 kernel_read = optarg;
2440 module_read = optarg;
2441 external_module = 1;
2444 external_module = 1;
2446 NOFAIL(malloc(sizeof(*extsym_iter)));
2447 extsym_iter->next = extsym_start;
2448 extsym_iter->file = optarg;
2449 extsym_start = extsym_iter;
2455 ignore_missing_files = 1;
2458 dump_write = optarg;
2464 vmlinux_section_warnings = 0;
2467 sec_mismatch_verbose = 0;
2470 files_source = optarg;
2473 warn_unresolved = 1;
2476 sec_mismatch_fatal = 1;
2484 read_dump(kernel_read, 1);
2486 read_dump(module_read, 0);
2487 while (extsym_start) {
2488 read_dump(extsym_start->file, 0);
2489 extsym_iter = extsym_start->next;
2491 extsym_start = extsym_iter;
2494 while (optind < argc)
2495 read_symbols(argv[optind++]);
2498 read_symbols_from_files(files_source);
2500 for (mod = modules; mod; mod = mod->next) {
2508 for (mod = modules; mod; mod = mod->next) {
2509 char fname[PATH_MAX];
2516 err |= check_modname_len(mod);
2517 add_header(&buf, mod);
2518 add_intree_flag(&buf, !external_module);
2519 add_retpoline(&buf);
2520 add_staging_flag(&buf, mod->name);
2521 err |= add_versions(&buf, mod);
2522 add_depends(&buf, mod, modules);
2523 add_moddevtable(&buf, mod);
2524 add_srcversion(&buf, mod);
2526 sprintf(fname, "%s.mod.c", mod->name);
2527 write_if_changed(&buf, fname);
2530 write_dump(dump_write);
2531 if (sec_mismatch_count) {
2532 if (!sec_mismatch_verbose) {
2533 warn("modpost: Found %d section mismatch(es).\n"
2534 "To see full details build your kernel with:\n"
2535 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2536 sec_mismatch_count);
2538 if (sec_mismatch_fatal) {
2539 fatal("modpost: Section mismatches detected.\n"
2540 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");