Merge branch 'v6v7' into devel
[linux/fpc-iii.git] / scripts / mod / modpost.c
blobe8fba959fffb4681f397857288c5aab4d159f895
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 ...
14 #define _GNU_SOURCE
15 #include <stdio.h>
16 #include <ctype.h>
17 #include <string.h>
18 #include "modpost.h"
19 #include "../../include/generated/autoconf.h"
20 #include "../../include/linux/license.h"
22 /* Some toolchains use a `_' prefix for all user symbols. */
23 #ifdef CONFIG_SYMBOL_PREFIX
24 #define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
25 #else
26 #define MODULE_SYMBOL_PREFIX ""
27 #endif
30 /* Are we using CONFIG_MODVERSIONS? */
31 int modversions = 0;
32 /* Warn about undefined symbols? (do so if we have vmlinux) */
33 int have_vmlinux = 0;
34 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
35 static int all_versions = 0;
36 /* If we are modposting external module set to 1 */
37 static int external_module = 0;
38 /* Warn about section mismatch in vmlinux if set to 1 */
39 static int vmlinux_section_warnings = 1;
40 /* Only warn about unresolved symbols */
41 static int warn_unresolved = 0;
42 /* How a symbol is exported */
43 static int sec_mismatch_count = 0;
44 static int sec_mismatch_verbose = 1;
46 enum export {
47 export_plain, export_unused, export_gpl,
48 export_unused_gpl, export_gpl_future, export_unknown
51 #define PRINTF __attribute__ ((format (printf, 1, 2)))
53 PRINTF void fatal(const char *fmt, ...)
55 va_list arglist;
57 fprintf(stderr, "FATAL: ");
59 va_start(arglist, fmt);
60 vfprintf(stderr, fmt, arglist);
61 va_end(arglist);
63 exit(1);
66 PRINTF void warn(const char *fmt, ...)
68 va_list arglist;
70 fprintf(stderr, "WARNING: ");
72 va_start(arglist, fmt);
73 vfprintf(stderr, fmt, arglist);
74 va_end(arglist);
77 PRINTF void merror(const char *fmt, ...)
79 va_list arglist;
81 fprintf(stderr, "ERROR: ");
83 va_start(arglist, fmt);
84 vfprintf(stderr, fmt, arglist);
85 va_end(arglist);
88 static int is_vmlinux(const char *modname)
90 const char *myname;
92 myname = strrchr(modname, '/');
93 if (myname)
94 myname++;
95 else
96 myname = modname;
98 return (strcmp(myname, "vmlinux") == 0) ||
99 (strcmp(myname, "vmlinux.o") == 0);
102 void *do_nofail(void *ptr, const char *expr)
104 if (!ptr)
105 fatal("modpost: Memory allocation failure: %s.\n", expr);
107 return ptr;
110 /* A list of all modules we processed */
111 static struct module *modules;
113 static struct module *find_module(char *modname)
115 struct module *mod;
117 for (mod = modules; mod; mod = mod->next)
118 if (strcmp(mod->name, modname) == 0)
119 break;
120 return mod;
123 static struct module *new_module(char *modname)
125 struct module *mod;
126 char *p, *s;
128 mod = NOFAIL(malloc(sizeof(*mod)));
129 memset(mod, 0, sizeof(*mod));
130 p = NOFAIL(strdup(modname));
132 /* strip trailing .o */
133 s = strrchr(p, '.');
134 if (s != NULL)
135 if (strcmp(s, ".o") == 0)
136 *s = '\0';
138 /* add to list */
139 mod->name = p;
140 mod->gpl_compatible = -1;
141 mod->next = modules;
142 modules = mod;
144 return mod;
147 /* A hash of all exported symbols,
148 * struct symbol is also used for lists of unresolved symbols */
150 #define SYMBOL_HASH_SIZE 1024
152 struct symbol {
153 struct symbol *next;
154 struct module *module;
155 unsigned int crc;
156 int crc_valid;
157 unsigned int weak:1;
158 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
159 unsigned int kernel:1; /* 1 if symbol is from kernel
160 * (only for external modules) **/
161 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
162 enum export export; /* Type of export */
163 char name[0];
166 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
168 /* This is based on the hash agorithm from gdbm, via tdb */
169 static inline unsigned int tdb_hash(const char *name)
171 unsigned value; /* Used to compute the hash value. */
172 unsigned i; /* Used to cycle through random values. */
174 /* Set the initial value from the key size. */
175 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
176 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
178 return (1103515243 * value + 12345);
182 * Allocate a new symbols for use in the hash of exported symbols or
183 * the list of unresolved symbols per module
185 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
186 struct symbol *next)
188 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
190 memset(s, 0, sizeof(*s));
191 strcpy(s->name, name);
192 s->weak = weak;
193 s->next = next;
194 return s;
197 /* For the hash of exported symbols */
198 static struct symbol *new_symbol(const char *name, struct module *module,
199 enum export export)
201 unsigned int hash;
202 struct symbol *new;
204 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
205 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
206 new->module = module;
207 new->export = export;
208 return new;
211 static struct symbol *find_symbol(const char *name)
213 struct symbol *s;
215 /* For our purposes, .foo matches foo. PPC64 needs this. */
216 if (name[0] == '.')
217 name++;
219 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
220 if (strcmp(s->name, name) == 0)
221 return s;
223 return NULL;
226 static struct {
227 const char *str;
228 enum export export;
229 } export_list[] = {
230 { .str = "EXPORT_SYMBOL", .export = export_plain },
231 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
232 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
233 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
234 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
235 { .str = "(unknown)", .export = export_unknown },
239 static const char *export_str(enum export ex)
241 return export_list[ex].str;
244 static enum export export_no(const char *s)
246 int i;
248 if (!s)
249 return export_unknown;
250 for (i = 0; export_list[i].export != export_unknown; i++) {
251 if (strcmp(export_list[i].str, s) == 0)
252 return export_list[i].export;
254 return export_unknown;
257 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
259 if (sec == elf->export_sec)
260 return export_plain;
261 else if (sec == elf->export_unused_sec)
262 return export_unused;
263 else if (sec == elf->export_gpl_sec)
264 return export_gpl;
265 else if (sec == elf->export_unused_gpl_sec)
266 return export_unused_gpl;
267 else if (sec == elf->export_gpl_future_sec)
268 return export_gpl_future;
269 else
270 return export_unknown;
274 * Add an exported symbol - it may have already been added without a
275 * CRC, in this case just update the CRC
277 static struct symbol *sym_add_exported(const char *name, struct module *mod,
278 enum export export)
280 struct symbol *s = find_symbol(name);
282 if (!s) {
283 s = new_symbol(name, mod, export);
284 } else {
285 if (!s->preloaded) {
286 warn("%s: '%s' exported twice. Previous export "
287 "was in %s%s\n", mod->name, name,
288 s->module->name,
289 is_vmlinux(s->module->name) ?"":".ko");
290 } else {
291 /* In case Modules.symvers was out of date */
292 s->module = mod;
295 s->preloaded = 0;
296 s->vmlinux = is_vmlinux(mod->name);
297 s->kernel = 0;
298 s->export = export;
299 return s;
302 static void sym_update_crc(const char *name, struct module *mod,
303 unsigned int crc, enum export export)
305 struct symbol *s = find_symbol(name);
307 if (!s)
308 s = new_symbol(name, mod, export);
309 s->crc = crc;
310 s->crc_valid = 1;
313 void *grab_file(const char *filename, unsigned long *size)
315 struct stat st;
316 void *map;
317 int fd;
319 fd = open(filename, O_RDONLY);
320 if (fd < 0 || fstat(fd, &st) != 0)
321 return NULL;
323 *size = st.st_size;
324 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
325 close(fd);
327 if (map == MAP_FAILED)
328 return NULL;
329 return map;
333 * Return a copy of the next line in a mmap'ed file.
334 * spaces in the beginning of the line is trimmed away.
335 * Return a pointer to a static buffer.
337 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
339 static char line[4096];
340 int skip = 1;
341 size_t len = 0;
342 signed char *p = (signed char *)file + *pos;
343 char *s = line;
345 for (; *pos < size ; (*pos)++) {
346 if (skip && isspace(*p)) {
347 p++;
348 continue;
350 skip = 0;
351 if (*p != '\n' && (*pos < size)) {
352 len++;
353 *s++ = *p++;
354 if (len > 4095)
355 break; /* Too long, stop */
356 } else {
357 /* End of string */
358 *s = '\0';
359 return line;
362 /* End of buffer */
363 return NULL;
366 void release_file(void *file, unsigned long size)
368 munmap(file, size);
371 static int parse_elf(struct elf_info *info, const char *filename)
373 unsigned int i;
374 Elf_Ehdr *hdr;
375 Elf_Shdr *sechdrs;
376 Elf_Sym *sym;
377 const char *secstrings;
378 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
380 hdr = grab_file(filename, &info->size);
381 if (!hdr) {
382 perror(filename);
383 exit(1);
385 info->hdr = hdr;
386 if (info->size < sizeof(*hdr)) {
387 /* file too small, assume this is an empty .o file */
388 return 0;
390 /* Is this a valid ELF file? */
391 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
392 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
393 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
394 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
395 /* Not an ELF file - silently ignore it */
396 return 0;
398 /* Fix endianness in ELF header */
399 hdr->e_type = TO_NATIVE(hdr->e_type);
400 hdr->e_machine = TO_NATIVE(hdr->e_machine);
401 hdr->e_version = TO_NATIVE(hdr->e_version);
402 hdr->e_entry = TO_NATIVE(hdr->e_entry);
403 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
404 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
405 hdr->e_flags = TO_NATIVE(hdr->e_flags);
406 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
407 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
408 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
409 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
410 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
411 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
412 sechdrs = (void *)hdr + hdr->e_shoff;
413 info->sechdrs = sechdrs;
415 /* Check if file offset is correct */
416 if (hdr->e_shoff > info->size) {
417 fatal("section header offset=%lu in file '%s' is bigger than "
418 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
419 filename, info->size);
420 return 0;
423 if (hdr->e_shnum == 0) {
425 * There are more than 64k sections,
426 * read count from .sh_size.
427 * note: it doesn't need shndx2secindex()
429 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
431 else {
432 info->num_sections = hdr->e_shnum;
434 if (hdr->e_shstrndx == SHN_XINDEX) {
435 info->secindex_strings =
436 shndx2secindex(TO_NATIVE(sechdrs[0].sh_link));
438 else {
439 info->secindex_strings = hdr->e_shstrndx;
442 /* Fix endianness in section headers */
443 for (i = 0; i < info->num_sections; i++) {
444 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
445 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
446 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
447 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
448 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
449 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
450 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
451 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
452 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
453 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
455 /* Find symbol table. */
456 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
457 for (i = 1; i < info->num_sections; i++) {
458 const char *secname;
459 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
461 if (!nobits && sechdrs[i].sh_offset > info->size) {
462 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
463 "sizeof(*hrd)=%zu\n", filename,
464 (unsigned long)sechdrs[i].sh_offset,
465 sizeof(*hdr));
466 return 0;
468 secname = secstrings + sechdrs[i].sh_name;
469 if (strcmp(secname, ".modinfo") == 0) {
470 if (nobits)
471 fatal("%s has NOBITS .modinfo\n", filename);
472 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
473 info->modinfo_len = sechdrs[i].sh_size;
474 } else if (strcmp(secname, "__ksymtab") == 0)
475 info->export_sec = i;
476 else if (strcmp(secname, "__ksymtab_unused") == 0)
477 info->export_unused_sec = i;
478 else if (strcmp(secname, "__ksymtab_gpl") == 0)
479 info->export_gpl_sec = i;
480 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
481 info->export_unused_gpl_sec = i;
482 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
483 info->export_gpl_future_sec = i;
485 if (sechdrs[i].sh_type == SHT_SYMTAB) {
486 unsigned int sh_link_idx;
487 symtab_idx = i;
488 info->symtab_start = (void *)hdr +
489 sechdrs[i].sh_offset;
490 info->symtab_stop = (void *)hdr +
491 sechdrs[i].sh_offset + sechdrs[i].sh_size;
492 sh_link_idx = shndx2secindex(sechdrs[i].sh_link);
493 info->strtab = (void *)hdr +
494 sechdrs[sh_link_idx].sh_offset;
497 /* 32bit section no. table? ("more than 64k sections") */
498 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
499 symtab_shndx_idx = i;
500 info->symtab_shndx_start = (void *)hdr +
501 sechdrs[i].sh_offset;
502 info->symtab_shndx_stop = (void *)hdr +
503 sechdrs[i].sh_offset + sechdrs[i].sh_size;
506 if (!info->symtab_start)
507 fatal("%s has no symtab?\n", filename);
509 /* Fix endianness in symbols */
510 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
511 sym->st_shndx = TO_NATIVE(sym->st_shndx);
512 sym->st_name = TO_NATIVE(sym->st_name);
513 sym->st_value = TO_NATIVE(sym->st_value);
514 sym->st_size = TO_NATIVE(sym->st_size);
517 if (symtab_shndx_idx != ~0U) {
518 Elf32_Word *p;
519 if (symtab_idx !=
520 shndx2secindex(sechdrs[symtab_shndx_idx].sh_link))
521 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
522 filename,
523 shndx2secindex(sechdrs[symtab_shndx_idx].sh_link),
524 symtab_idx);
525 /* Fix endianness */
526 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
527 p++)
528 *p = TO_NATIVE(*p);
531 return 1;
534 static void parse_elf_finish(struct elf_info *info)
536 release_file(info->hdr, info->size);
539 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
541 /* ignore __this_module, it will be resolved shortly */
542 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
543 return 1;
544 /* ignore global offset table */
545 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
546 return 1;
547 if (info->hdr->e_machine == EM_PPC)
548 /* Special register function linked on all modules during final link of .ko */
549 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
550 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
551 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
552 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
553 return 1;
554 if (info->hdr->e_machine == EM_PPC64)
555 /* Special register function linked on all modules during final link of .ko */
556 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
557 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
558 return 1;
559 /* Do not ignore this symbol */
560 return 0;
563 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
564 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
566 static void handle_modversions(struct module *mod, struct elf_info *info,
567 Elf_Sym *sym, const char *symname)
569 unsigned int crc;
570 enum export export = export_from_sec(info, get_secindex(info, sym));
572 switch (sym->st_shndx) {
573 case SHN_COMMON:
574 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
575 break;
576 case SHN_ABS:
577 /* CRC'd symbol */
578 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
579 crc = (unsigned int) sym->st_value;
580 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
581 export);
583 break;
584 case SHN_UNDEF:
585 /* undefined symbol */
586 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
587 ELF_ST_BIND(sym->st_info) != STB_WEAK)
588 break;
589 if (ignore_undef_symbol(info, symname))
590 break;
591 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
592 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
593 /* add compatibility with older glibc */
594 #ifndef STT_SPARC_REGISTER
595 #define STT_SPARC_REGISTER STT_REGISTER
596 #endif
597 if (info->hdr->e_machine == EM_SPARC ||
598 info->hdr->e_machine == EM_SPARCV9) {
599 /* Ignore register directives. */
600 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
601 break;
602 if (symname[0] == '.') {
603 char *munged = strdup(symname);
604 munged[0] = '_';
605 munged[1] = toupper(munged[1]);
606 symname = munged;
609 #endif
611 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
612 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
613 mod->unres =
614 alloc_symbol(symname +
615 strlen(MODULE_SYMBOL_PREFIX),
616 ELF_ST_BIND(sym->st_info) == STB_WEAK,
617 mod->unres);
619 break;
620 default:
621 /* All exported symbols */
622 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
623 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
624 export);
626 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
627 mod->has_init = 1;
628 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
629 mod->has_cleanup = 1;
630 break;
635 * Parse tag=value strings from .modinfo section
637 static char *next_string(char *string, unsigned long *secsize)
639 /* Skip non-zero chars */
640 while (string[0]) {
641 string++;
642 if ((*secsize)-- <= 1)
643 return NULL;
646 /* Skip any zero padding. */
647 while (!string[0]) {
648 string++;
649 if ((*secsize)-- <= 1)
650 return NULL;
652 return string;
655 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
656 const char *tag, char *info)
658 char *p;
659 unsigned int taglen = strlen(tag);
660 unsigned long size = modinfo_len;
662 if (info) {
663 size -= info - (char *)modinfo;
664 modinfo = next_string(info, &size);
667 for (p = modinfo; p; p = next_string(p, &size)) {
668 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
669 return p + taglen + 1;
671 return NULL;
674 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
675 const char *tag)
678 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
682 * Test if string s ends in string sub
683 * return 0 if match
685 static int strrcmp(const char *s, const char *sub)
687 int slen, sublen;
689 if (!s || !sub)
690 return 1;
692 slen = strlen(s);
693 sublen = strlen(sub);
695 if ((slen == 0) || (sublen == 0))
696 return 1;
698 if (sublen > slen)
699 return 1;
701 return memcmp(s + slen - sublen, sub, sublen);
704 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
706 if (sym)
707 return elf->strtab + sym->st_name;
708 else
709 return "(unknown)";
712 static const char *sec_name(struct elf_info *elf, int secindex)
714 Elf_Shdr *sechdrs = elf->sechdrs;
715 return (void *)elf->hdr +
716 elf->sechdrs[elf->secindex_strings].sh_offset +
717 sechdrs[secindex].sh_name;
720 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
722 return (void *)elf->hdr +
723 elf->sechdrs[elf->secindex_strings].sh_offset +
724 sechdr->sh_name;
727 /* if sym is empty or point to a string
728 * like ".[0-9]+" then return 1.
729 * This is the optional prefix added by ld to some sections
731 static int number_prefix(const char *sym)
733 if (*sym++ == '\0')
734 return 1;
735 if (*sym != '.')
736 return 0;
737 do {
738 char c = *sym++;
739 if (c < '0' || c > '9')
740 return 0;
741 } while (*sym);
742 return 1;
745 /* The pattern is an array of simple patterns.
746 * "foo" will match an exact string equal to "foo"
747 * "*foo" will match a string that ends with "foo"
748 * "foo*" will match a string that begins with "foo"
749 * "foo$" will match a string equal to "foo" or "foo.1"
750 * where the '1' can be any number including several digits.
751 * The $ syntax is for sections where ld append a dot number
752 * to make section name unique.
754 static int match(const char *sym, const char * const pat[])
756 const char *p;
757 while (*pat) {
758 p = *pat++;
759 const char *endp = p + strlen(p) - 1;
761 /* "*foo" */
762 if (*p == '*') {
763 if (strrcmp(sym, p + 1) == 0)
764 return 1;
766 /* "foo*" */
767 else if (*endp == '*') {
768 if (strncmp(sym, p, strlen(p) - 1) == 0)
769 return 1;
771 /* "foo$" */
772 else if (*endp == '$') {
773 if (strncmp(sym, p, strlen(p) - 1) == 0) {
774 if (number_prefix(sym + strlen(p) - 1))
775 return 1;
778 /* no wildcards */
779 else {
780 if (strcmp(p, sym) == 0)
781 return 1;
784 /* no match */
785 return 0;
788 /* sections that we do not want to do full section mismatch check on */
789 static const char *section_white_list[] =
791 ".comment*",
792 ".debug*",
793 ".zdebug*", /* Compressed debug sections. */
794 ".GCC-command-line", /* mn10300 */
795 ".mdebug*", /* alpha, score, mips etc. */
796 ".pdr", /* alpha, score, mips etc. */
797 ".stab*",
798 ".note*",
799 ".got*",
800 ".toc*",
801 NULL
805 * This is used to find sections missing the SHF_ALLOC flag.
806 * The cause of this is often a section specified in assembler
807 * without "ax" / "aw".
809 static void check_section(const char *modname, struct elf_info *elf,
810 Elf_Shdr *sechdr)
812 const char *sec = sech_name(elf, sechdr);
814 if (sechdr->sh_type == SHT_PROGBITS &&
815 !(sechdr->sh_flags & SHF_ALLOC) &&
816 !match(sec, section_white_list)) {
817 warn("%s (%s): unexpected non-allocatable section.\n"
818 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
819 "Note that for example <linux/init.h> contains\n"
820 "section definitions for use in .S files.\n\n",
821 modname, sec);
827 #define ALL_INIT_DATA_SECTIONS \
828 ".init.setup$", ".init.rodata$", \
829 ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$" \
830 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
831 #define ALL_EXIT_DATA_SECTIONS \
832 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
834 #define ALL_INIT_TEXT_SECTIONS \
835 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
836 #define ALL_EXIT_TEXT_SECTIONS \
837 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
839 #define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
840 MEM_INIT_SECTIONS
841 #define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
842 MEM_EXIT_SECTIONS
844 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
845 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
847 #define DATA_SECTIONS ".data$", ".data.rel$"
848 #define TEXT_SECTIONS ".text$"
850 #define INIT_SECTIONS ".init.*"
851 #define DEV_INIT_SECTIONS ".devinit.*"
852 #define CPU_INIT_SECTIONS ".cpuinit.*"
853 #define MEM_INIT_SECTIONS ".meminit.*"
855 #define EXIT_SECTIONS ".exit.*"
856 #define DEV_EXIT_SECTIONS ".devexit.*"
857 #define CPU_EXIT_SECTIONS ".cpuexit.*"
858 #define MEM_EXIT_SECTIONS ".memexit.*"
860 /* init data sections */
861 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
863 /* all init sections */
864 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
866 /* All init and exit sections (code + data) */
867 static const char *init_exit_sections[] =
868 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
870 /* data section */
871 static const char *data_sections[] = { DATA_SECTIONS, NULL };
874 /* symbols in .data that may refer to init/exit sections */
875 #define DEFAULT_SYMBOL_WHITE_LIST \
876 "*driver", \
877 "*_template", /* scsi uses *_template a lot */ \
878 "*_timer", /* arm uses ops structures named _timer a lot */ \
879 "*_sht", /* scsi also used *_sht to some extent */ \
880 "*_ops", \
881 "*_probe", \
882 "*_probe_one", \
883 "*_console"
885 static const char *head_sections[] = { ".head.text*", NULL };
886 static const char *linker_symbols[] =
887 { "__init_begin", "_sinittext", "_einittext", NULL };
889 enum mismatch {
890 TEXT_TO_ANY_INIT,
891 DATA_TO_ANY_INIT,
892 TEXT_TO_ANY_EXIT,
893 DATA_TO_ANY_EXIT,
894 XXXINIT_TO_SOME_INIT,
895 XXXEXIT_TO_SOME_EXIT,
896 ANY_INIT_TO_ANY_EXIT,
897 ANY_EXIT_TO_ANY_INIT,
898 EXPORT_TO_INIT_EXIT,
901 struct sectioncheck {
902 const char *fromsec[20];
903 const char *tosec[20];
904 enum mismatch mismatch;
905 const char *symbol_white_list[20];
908 const struct sectioncheck sectioncheck[] = {
909 /* Do not reference init/exit code/data from
910 * normal code and data
913 .fromsec = { TEXT_SECTIONS, NULL },
914 .tosec = { ALL_INIT_SECTIONS, NULL },
915 .mismatch = TEXT_TO_ANY_INIT,
916 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
919 .fromsec = { DATA_SECTIONS, NULL },
920 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
921 .mismatch = DATA_TO_ANY_INIT,
922 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
925 .fromsec = { DATA_SECTIONS, NULL },
926 .tosec = { INIT_SECTIONS, NULL },
927 .mismatch = DATA_TO_ANY_INIT,
928 .symbol_white_list = {
929 "*_template", "*_timer", "*_sht", "*_ops",
930 "*_probe", "*_probe_one", "*_console", NULL
934 .fromsec = { TEXT_SECTIONS, NULL },
935 .tosec = { ALL_EXIT_SECTIONS, NULL },
936 .mismatch = TEXT_TO_ANY_EXIT,
937 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
940 .fromsec = { DATA_SECTIONS, NULL },
941 .tosec = { ALL_EXIT_SECTIONS, NULL },
942 .mismatch = DATA_TO_ANY_EXIT,
943 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
945 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */
947 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
948 .tosec = { INIT_SECTIONS, NULL },
949 .mismatch = XXXINIT_TO_SOME_INIT,
950 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
952 /* Do not reference cpuinit code/data from meminit code/data */
954 .fromsec = { MEM_INIT_SECTIONS, NULL },
955 .tosec = { CPU_INIT_SECTIONS, NULL },
956 .mismatch = XXXINIT_TO_SOME_INIT,
957 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
959 /* Do not reference meminit code/data from cpuinit code/data */
961 .fromsec = { CPU_INIT_SECTIONS, NULL },
962 .tosec = { MEM_INIT_SECTIONS, NULL },
963 .mismatch = XXXINIT_TO_SOME_INIT,
964 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
966 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
968 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
969 .tosec = { EXIT_SECTIONS, NULL },
970 .mismatch = XXXEXIT_TO_SOME_EXIT,
971 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
973 /* Do not reference cpuexit code/data from memexit code/data */
975 .fromsec = { MEM_EXIT_SECTIONS, NULL },
976 .tosec = { CPU_EXIT_SECTIONS, NULL },
977 .mismatch = XXXEXIT_TO_SOME_EXIT,
978 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
980 /* Do not reference memexit code/data from cpuexit code/data */
982 .fromsec = { CPU_EXIT_SECTIONS, NULL },
983 .tosec = { MEM_EXIT_SECTIONS, NULL },
984 .mismatch = XXXEXIT_TO_SOME_EXIT,
985 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
987 /* Do not use exit code/data from init code */
989 .fromsec = { ALL_INIT_SECTIONS, NULL },
990 .tosec = { ALL_EXIT_SECTIONS, NULL },
991 .mismatch = ANY_INIT_TO_ANY_EXIT,
992 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
994 /* Do not use init code/data from exit code */
996 .fromsec = { ALL_EXIT_SECTIONS, NULL },
997 .tosec = { ALL_INIT_SECTIONS, NULL },
998 .mismatch = ANY_EXIT_TO_ANY_INIT,
999 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1001 /* Do not export init/exit functions or data */
1003 .fromsec = { "__ksymtab*", NULL },
1004 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1005 .mismatch = EXPORT_TO_INIT_EXIT,
1006 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1010 static const struct sectioncheck *section_mismatch(
1011 const char *fromsec, const char *tosec)
1013 int i;
1014 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1015 const struct sectioncheck *check = &sectioncheck[0];
1017 for (i = 0; i < elems; i++) {
1018 if (match(fromsec, check->fromsec) &&
1019 match(tosec, check->tosec))
1020 return check;
1021 check++;
1023 return NULL;
1027 * Whitelist to allow certain references to pass with no warning.
1029 * Pattern 1:
1030 * If a module parameter is declared __initdata and permissions=0
1031 * then this is legal despite the warning generated.
1032 * We cannot see value of permissions here, so just ignore
1033 * this pattern.
1034 * The pattern is identified by:
1035 * tosec = .init.data
1036 * fromsec = .data*
1037 * atsym =__param*
1039 * Pattern 1a:
1040 * module_param_call() ops can refer to __init set function if permissions=0
1041 * The pattern is identified by:
1042 * tosec = .init.text
1043 * fromsec = .data*
1044 * atsym = __param_ops_*
1046 * Pattern 2:
1047 * Many drivers utilise a *driver container with references to
1048 * add, remove, probe functions etc.
1049 * These functions may often be marked __devinit and we do not want to
1050 * warn here.
1051 * the pattern is identified by:
1052 * tosec = init or exit section
1053 * fromsec = data section
1054 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1055 * *probe_one, *_console, *_timer
1057 * Pattern 3:
1058 * Whitelist all references from .head.text to any init section
1060 * Pattern 4:
1061 * Some symbols belong to init section but still it is ok to reference
1062 * these from non-init sections as these symbols don't have any memory
1063 * allocated for them and symbol address and value are same. So even
1064 * if init section is freed, its ok to reference those symbols.
1065 * For ex. symbols marking the init section boundaries.
1066 * This pattern is identified by
1067 * refsymname = __init_begin, _sinittext, _einittext
1070 static int secref_whitelist(const struct sectioncheck *mismatch,
1071 const char *fromsec, const char *fromsym,
1072 const char *tosec, const char *tosym)
1074 /* Check for pattern 1 */
1075 if (match(tosec, init_data_sections) &&
1076 match(fromsec, data_sections) &&
1077 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1078 return 0;
1080 /* Check for pattern 1a */
1081 if (strcmp(tosec, ".init.text") == 0 &&
1082 match(fromsec, data_sections) &&
1083 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1084 return 0;
1086 /* Check for pattern 2 */
1087 if (match(tosec, init_exit_sections) &&
1088 match(fromsec, data_sections) &&
1089 match(fromsym, mismatch->symbol_white_list))
1090 return 0;
1092 /* Check for pattern 3 */
1093 if (match(fromsec, head_sections) &&
1094 match(tosec, init_sections))
1095 return 0;
1097 /* Check for pattern 4 */
1098 if (match(tosym, linker_symbols))
1099 return 0;
1101 return 1;
1105 * Find symbol based on relocation record info.
1106 * In some cases the symbol supplied is a valid symbol so
1107 * return refsym. If st_name != 0 we assume this is a valid symbol.
1108 * In other cases the symbol needs to be looked up in the symbol table
1109 * based on section and address.
1110 * **/
1111 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1112 Elf_Sym *relsym)
1114 Elf_Sym *sym;
1115 Elf_Sym *near = NULL;
1116 Elf64_Sword distance = 20;
1117 Elf64_Sword d;
1118 unsigned int relsym_secindex;
1120 if (relsym->st_name != 0)
1121 return relsym;
1123 relsym_secindex = get_secindex(elf, relsym);
1124 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1125 if (get_secindex(elf, sym) != relsym_secindex)
1126 continue;
1127 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1128 continue;
1129 if (sym->st_value == addr)
1130 return sym;
1131 /* Find a symbol nearby - addr are maybe negative */
1132 d = sym->st_value - addr;
1133 if (d < 0)
1134 d = addr - sym->st_value;
1135 if (d < distance) {
1136 distance = d;
1137 near = sym;
1140 /* We need a close match */
1141 if (distance < 20)
1142 return near;
1143 else
1144 return NULL;
1147 static inline int is_arm_mapping_symbol(const char *str)
1149 return str[0] == '$' && strchr("atd", str[1])
1150 && (str[2] == '\0' || str[2] == '.');
1154 * If there's no name there, ignore it; likewise, ignore it if it's
1155 * one of the magic symbols emitted used by current ARM tools.
1157 * Otherwise if find_symbols_between() returns those symbols, they'll
1158 * fail the whitelist tests and cause lots of false alarms ... fixable
1159 * only by merging __exit and __init sections into __text, bloating
1160 * the kernel (which is especially evil on embedded platforms).
1162 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1164 const char *name = elf->strtab + sym->st_name;
1166 if (!name || !strlen(name))
1167 return 0;
1168 return !is_arm_mapping_symbol(name);
1172 * Find symbols before or equal addr and after addr - in the section sec.
1173 * If we find two symbols with equal offset prefer one with a valid name.
1174 * The ELF format may have a better way to detect what type of symbol
1175 * it is, but this works for now.
1177 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1178 const char *sec)
1180 Elf_Sym *sym;
1181 Elf_Sym *near = NULL;
1182 Elf_Addr distance = ~0;
1184 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1185 const char *symsec;
1187 if (is_shndx_special(sym->st_shndx))
1188 continue;
1189 symsec = sec_name(elf, get_secindex(elf, sym));
1190 if (strcmp(symsec, sec) != 0)
1191 continue;
1192 if (!is_valid_name(elf, sym))
1193 continue;
1194 if (sym->st_value <= addr) {
1195 if ((addr - sym->st_value) < distance) {
1196 distance = addr - sym->st_value;
1197 near = sym;
1198 } else if ((addr - sym->st_value) == distance) {
1199 near = sym;
1203 return near;
1207 * Convert a section name to the function/data attribute
1208 * .init.text => __init
1209 * .cpuinit.data => __cpudata
1210 * .memexitconst => __memconst
1211 * etc.
1213 * The memory of returned value has been allocated on a heap. The user of this
1214 * method should free it after usage.
1216 static char *sec2annotation(const char *s)
1218 if (match(s, init_exit_sections)) {
1219 char *p = malloc(20);
1220 char *r = p;
1222 *p++ = '_';
1223 *p++ = '_';
1224 if (*s == '.')
1225 s++;
1226 while (*s && *s != '.')
1227 *p++ = *s++;
1228 *p = '\0';
1229 if (*s == '.')
1230 s++;
1231 if (strstr(s, "rodata") != NULL)
1232 strcat(p, "const ");
1233 else if (strstr(s, "data") != NULL)
1234 strcat(p, "data ");
1235 else
1236 strcat(p, " ");
1237 return r;
1238 } else {
1239 return strdup("");
1243 static int is_function(Elf_Sym *sym)
1245 if (sym)
1246 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1247 else
1248 return -1;
1252 * Print a warning about a section mismatch.
1253 * Try to find symbols near it so user can find it.
1254 * Check whitelist before warning - it may be a false positive.
1256 static void report_sec_mismatch(const char *modname,
1257 const struct sectioncheck *mismatch,
1258 const char *fromsec,
1259 unsigned long long fromaddr,
1260 const char *fromsym,
1261 int from_is_func,
1262 const char *tosec, const char *tosym,
1263 int to_is_func)
1265 const char *from, *from_p;
1266 const char *to, *to_p;
1267 char *prl_from;
1268 char *prl_to;
1270 switch (from_is_func) {
1271 case 0: from = "variable"; from_p = ""; break;
1272 case 1: from = "function"; from_p = "()"; break;
1273 default: from = "(unknown reference)"; from_p = ""; break;
1275 switch (to_is_func) {
1276 case 0: to = "variable"; to_p = ""; break;
1277 case 1: to = "function"; to_p = "()"; break;
1278 default: to = "(unknown reference)"; to_p = ""; break;
1281 sec_mismatch_count++;
1282 if (!sec_mismatch_verbose)
1283 return;
1285 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1286 "to the %s %s:%s%s\n",
1287 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1288 tosym, to_p);
1290 switch (mismatch->mismatch) {
1291 case TEXT_TO_ANY_INIT:
1292 prl_from = sec2annotation(fromsec);
1293 prl_to = sec2annotation(tosec);
1294 fprintf(stderr,
1295 "The function %s%s() references\n"
1296 "the %s %s%s%s.\n"
1297 "This is often because %s lacks a %s\n"
1298 "annotation or the annotation of %s is wrong.\n",
1299 prl_from, fromsym,
1300 to, prl_to, tosym, to_p,
1301 fromsym, prl_to, tosym);
1302 free(prl_from);
1303 free(prl_to);
1304 break;
1305 case DATA_TO_ANY_INIT: {
1306 prl_to = sec2annotation(tosec);
1307 const char *const *s = mismatch->symbol_white_list;
1308 fprintf(stderr,
1309 "The variable %s references\n"
1310 "the %s %s%s%s\n"
1311 "If the reference is valid then annotate the\n"
1312 "variable with __init* or __refdata (see linux/init.h) "
1313 "or name the variable:\n",
1314 fromsym, to, prl_to, tosym, to_p);
1315 while (*s)
1316 fprintf(stderr, "%s, ", *s++);
1317 fprintf(stderr, "\n");
1318 free(prl_to);
1319 break;
1321 case TEXT_TO_ANY_EXIT:
1322 prl_to = sec2annotation(tosec);
1323 fprintf(stderr,
1324 "The function %s() references a %s in an exit section.\n"
1325 "Often the %s %s%s has valid usage outside the exit section\n"
1326 "and the fix is to remove the %sannotation of %s.\n",
1327 fromsym, to, to, tosym, to_p, prl_to, tosym);
1328 free(prl_to);
1329 break;
1330 case DATA_TO_ANY_EXIT: {
1331 prl_to = sec2annotation(tosec);
1332 const char *const *s = mismatch->symbol_white_list;
1333 fprintf(stderr,
1334 "The variable %s references\n"
1335 "the %s %s%s%s\n"
1336 "If the reference is valid then annotate the\n"
1337 "variable with __exit* (see linux/init.h) or "
1338 "name the variable:\n",
1339 fromsym, to, prl_to, tosym, to_p);
1340 while (*s)
1341 fprintf(stderr, "%s, ", *s++);
1342 fprintf(stderr, "\n");
1343 free(prl_to);
1344 break;
1346 case XXXINIT_TO_SOME_INIT:
1347 case XXXEXIT_TO_SOME_EXIT:
1348 prl_from = sec2annotation(fromsec);
1349 prl_to = sec2annotation(tosec);
1350 fprintf(stderr,
1351 "The %s %s%s%s references\n"
1352 "a %s %s%s%s.\n"
1353 "If %s is only used by %s then\n"
1354 "annotate %s with a matching annotation.\n",
1355 from, prl_from, fromsym, from_p,
1356 to, prl_to, tosym, to_p,
1357 tosym, fromsym, tosym);
1358 free(prl_from);
1359 free(prl_to);
1360 break;
1361 case ANY_INIT_TO_ANY_EXIT:
1362 prl_from = sec2annotation(fromsec);
1363 prl_to = sec2annotation(tosec);
1364 fprintf(stderr,
1365 "The %s %s%s%s references\n"
1366 "a %s %s%s%s.\n"
1367 "This is often seen when error handling "
1368 "in the init function\n"
1369 "uses functionality in the exit path.\n"
1370 "The fix is often to remove the %sannotation of\n"
1371 "%s%s so it may be used outside an exit section.\n",
1372 from, prl_from, fromsym, from_p,
1373 to, prl_to, tosym, to_p,
1374 prl_to, tosym, to_p);
1375 free(prl_from);
1376 free(prl_to);
1377 break;
1378 case ANY_EXIT_TO_ANY_INIT:
1379 prl_from = sec2annotation(fromsec);
1380 prl_to = sec2annotation(tosec);
1381 fprintf(stderr,
1382 "The %s %s%s%s references\n"
1383 "a %s %s%s%s.\n"
1384 "This is often seen when error handling "
1385 "in the exit function\n"
1386 "uses functionality in the init path.\n"
1387 "The fix is often to remove the %sannotation of\n"
1388 "%s%s so it may be used outside an init section.\n",
1389 from, prl_from, fromsym, from_p,
1390 to, prl_to, tosym, to_p,
1391 prl_to, tosym, to_p);
1392 free(prl_from);
1393 free(prl_to);
1394 break;
1395 case EXPORT_TO_INIT_EXIT:
1396 prl_to = sec2annotation(tosec);
1397 fprintf(stderr,
1398 "The symbol %s is exported and annotated %s\n"
1399 "Fix this by removing the %sannotation of %s "
1400 "or drop the export.\n",
1401 tosym, prl_to, prl_to, tosym);
1402 free(prl_to);
1403 break;
1405 fprintf(stderr, "\n");
1408 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1409 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1411 const char *tosec;
1412 const struct sectioncheck *mismatch;
1414 tosec = sec_name(elf, get_secindex(elf, sym));
1415 mismatch = section_mismatch(fromsec, tosec);
1416 if (mismatch) {
1417 Elf_Sym *to;
1418 Elf_Sym *from;
1419 const char *tosym;
1420 const char *fromsym;
1422 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1423 fromsym = sym_name(elf, from);
1424 to = find_elf_symbol(elf, r->r_addend, sym);
1425 tosym = sym_name(elf, to);
1427 /* check whitelist - we may ignore it */
1428 if (secref_whitelist(mismatch,
1429 fromsec, fromsym, tosec, tosym)) {
1430 report_sec_mismatch(modname, mismatch,
1431 fromsec, r->r_offset, fromsym,
1432 is_function(from), tosec, tosym,
1433 is_function(to));
1438 static unsigned int *reloc_location(struct elf_info *elf,
1439 Elf_Shdr *sechdr, Elf_Rela *r)
1441 Elf_Shdr *sechdrs = elf->sechdrs;
1442 int section = shndx2secindex(sechdr->sh_info);
1444 return (void *)elf->hdr + sechdrs[section].sh_offset +
1445 r->r_offset;
1448 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1450 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1451 unsigned int *location = reloc_location(elf, sechdr, r);
1453 switch (r_typ) {
1454 case R_386_32:
1455 r->r_addend = TO_NATIVE(*location);
1456 break;
1457 case R_386_PC32:
1458 r->r_addend = TO_NATIVE(*location) + 4;
1459 /* For CONFIG_RELOCATABLE=y */
1460 if (elf->hdr->e_type == ET_EXEC)
1461 r->r_addend += r->r_offset;
1462 break;
1464 return 0;
1467 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1469 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1471 switch (r_typ) {
1472 case R_ARM_ABS32:
1473 /* From ARM ABI: (S + A) | T */
1474 r->r_addend = (int)(long)
1475 (elf->symtab_start + ELF_R_SYM(r->r_info));
1476 break;
1477 case R_ARM_PC24:
1478 /* From ARM ABI: ((S + A) | T) - P */
1479 r->r_addend = (int)(long)(elf->hdr +
1480 sechdr->sh_offset +
1481 (r->r_offset - sechdr->sh_addr));
1482 break;
1483 default:
1484 return 1;
1486 return 0;
1489 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1491 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1492 unsigned int *location = reloc_location(elf, sechdr, r);
1493 unsigned int inst;
1495 if (r_typ == R_MIPS_HI16)
1496 return 1; /* skip this */
1497 inst = TO_NATIVE(*location);
1498 switch (r_typ) {
1499 case R_MIPS_LO16:
1500 r->r_addend = inst & 0xffff;
1501 break;
1502 case R_MIPS_26:
1503 r->r_addend = (inst & 0x03ffffff) << 2;
1504 break;
1505 case R_MIPS_32:
1506 r->r_addend = inst;
1507 break;
1509 return 0;
1512 static void section_rela(const char *modname, struct elf_info *elf,
1513 Elf_Shdr *sechdr)
1515 Elf_Sym *sym;
1516 Elf_Rela *rela;
1517 Elf_Rela r;
1518 unsigned int r_sym;
1519 const char *fromsec;
1521 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1522 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1524 fromsec = sech_name(elf, sechdr);
1525 fromsec += strlen(".rela");
1526 /* if from section (name) is know good then skip it */
1527 if (match(fromsec, section_white_list))
1528 return;
1530 for (rela = start; rela < stop; rela++) {
1531 r.r_offset = TO_NATIVE(rela->r_offset);
1532 #if KERNEL_ELFCLASS == ELFCLASS64
1533 if (elf->hdr->e_machine == EM_MIPS) {
1534 unsigned int r_typ;
1535 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1536 r_sym = TO_NATIVE(r_sym);
1537 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1538 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1539 } else {
1540 r.r_info = TO_NATIVE(rela->r_info);
1541 r_sym = ELF_R_SYM(r.r_info);
1543 #else
1544 r.r_info = TO_NATIVE(rela->r_info);
1545 r_sym = ELF_R_SYM(r.r_info);
1546 #endif
1547 r.r_addend = TO_NATIVE(rela->r_addend);
1548 sym = elf->symtab_start + r_sym;
1549 /* Skip special sections */
1550 if (is_shndx_special(sym->st_shndx))
1551 continue;
1552 check_section_mismatch(modname, elf, &r, sym, fromsec);
1556 static void section_rel(const char *modname, struct elf_info *elf,
1557 Elf_Shdr *sechdr)
1559 Elf_Sym *sym;
1560 Elf_Rel *rel;
1561 Elf_Rela r;
1562 unsigned int r_sym;
1563 const char *fromsec;
1565 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1566 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1568 fromsec = sech_name(elf, sechdr);
1569 fromsec += strlen(".rel");
1570 /* if from section (name) is know good then skip it */
1571 if (match(fromsec, section_white_list))
1572 return;
1574 for (rel = start; rel < stop; rel++) {
1575 r.r_offset = TO_NATIVE(rel->r_offset);
1576 #if KERNEL_ELFCLASS == ELFCLASS64
1577 if (elf->hdr->e_machine == EM_MIPS) {
1578 unsigned int r_typ;
1579 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1580 r_sym = TO_NATIVE(r_sym);
1581 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1582 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1583 } else {
1584 r.r_info = TO_NATIVE(rel->r_info);
1585 r_sym = ELF_R_SYM(r.r_info);
1587 #else
1588 r.r_info = TO_NATIVE(rel->r_info);
1589 r_sym = ELF_R_SYM(r.r_info);
1590 #endif
1591 r.r_addend = 0;
1592 switch (elf->hdr->e_machine) {
1593 case EM_386:
1594 if (addend_386_rel(elf, sechdr, &r))
1595 continue;
1596 break;
1597 case EM_ARM:
1598 if (addend_arm_rel(elf, sechdr, &r))
1599 continue;
1600 break;
1601 case EM_MIPS:
1602 if (addend_mips_rel(elf, sechdr, &r))
1603 continue;
1604 break;
1606 sym = elf->symtab_start + r_sym;
1607 /* Skip special sections */
1608 if (is_shndx_special(sym->st_shndx))
1609 continue;
1610 check_section_mismatch(modname, elf, &r, sym, fromsec);
1615 * A module includes a number of sections that are discarded
1616 * either when loaded or when used as built-in.
1617 * For loaded modules all functions marked __init and all data
1618 * marked __initdata will be discarded when the module has been initialized.
1619 * Likewise for modules used built-in the sections marked __exit
1620 * are discarded because __exit marked function are supposed to be called
1621 * only when a module is unloaded which never happens for built-in modules.
1622 * The check_sec_ref() function traverses all relocation records
1623 * to find all references to a section that reference a section that will
1624 * be discarded and warns about it.
1626 static void check_sec_ref(struct module *mod, const char *modname,
1627 struct elf_info *elf)
1629 int i;
1630 Elf_Shdr *sechdrs = elf->sechdrs;
1632 /* Walk through all sections */
1633 for (i = 0; i < elf->num_sections; i++) {
1634 check_section(modname, elf, &elf->sechdrs[i]);
1635 /* We want to process only relocation sections and not .init */
1636 if (sechdrs[i].sh_type == SHT_RELA)
1637 section_rela(modname, elf, &elf->sechdrs[i]);
1638 else if (sechdrs[i].sh_type == SHT_REL)
1639 section_rel(modname, elf, &elf->sechdrs[i]);
1643 static void read_symbols(char *modname)
1645 const char *symname;
1646 char *version;
1647 char *license;
1648 struct module *mod;
1649 struct elf_info info = { };
1650 Elf_Sym *sym;
1652 if (!parse_elf(&info, modname))
1653 return;
1655 mod = new_module(modname);
1657 /* When there's no vmlinux, don't print warnings about
1658 * unresolved symbols (since there'll be too many ;) */
1659 if (is_vmlinux(modname)) {
1660 have_vmlinux = 1;
1661 mod->skip = 1;
1664 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1665 if (info.modinfo && !license && !is_vmlinux(modname))
1666 warn("modpost: missing MODULE_LICENSE() in %s\n"
1667 "see include/linux/module.h for "
1668 "more information\n", modname);
1669 while (license) {
1670 if (license_is_gpl_compatible(license))
1671 mod->gpl_compatible = 1;
1672 else {
1673 mod->gpl_compatible = 0;
1674 break;
1676 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1677 "license", license);
1680 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1681 symname = info.strtab + sym->st_name;
1683 handle_modversions(mod, &info, sym, symname);
1684 handle_moddevtable(mod, &info, sym, symname);
1686 if (!is_vmlinux(modname) ||
1687 (is_vmlinux(modname) && vmlinux_section_warnings))
1688 check_sec_ref(mod, modname, &info);
1690 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1691 if (version)
1692 maybe_frob_rcs_version(modname, version, info.modinfo,
1693 version - (char *)info.hdr);
1694 if (version || (all_versions && !is_vmlinux(modname)))
1695 get_src_version(modname, mod->srcversion,
1696 sizeof(mod->srcversion)-1);
1698 parse_elf_finish(&info);
1700 /* Our trick to get versioning for module struct etc. - it's
1701 * never passed as an argument to an exported function, so
1702 * the automatic versioning doesn't pick it up, but it's really
1703 * important anyhow */
1704 if (modversions)
1705 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1708 #define SZ 500
1710 /* We first write the generated file into memory using the
1711 * following helper, then compare to the file on disk and
1712 * only update the later if anything changed */
1714 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1715 const char *fmt, ...)
1717 char tmp[SZ];
1718 int len;
1719 va_list ap;
1721 va_start(ap, fmt);
1722 len = vsnprintf(tmp, SZ, fmt, ap);
1723 buf_write(buf, tmp, len);
1724 va_end(ap);
1727 void buf_write(struct buffer *buf, const char *s, int len)
1729 if (buf->size - buf->pos < len) {
1730 buf->size += len + SZ;
1731 buf->p = realloc(buf->p, buf->size);
1733 strncpy(buf->p + buf->pos, s, len);
1734 buf->pos += len;
1737 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1739 const char *e = is_vmlinux(m) ?"":".ko";
1741 switch (exp) {
1742 case export_gpl:
1743 fatal("modpost: GPL-incompatible module %s%s "
1744 "uses GPL-only symbol '%s'\n", m, e, s);
1745 break;
1746 case export_unused_gpl:
1747 fatal("modpost: GPL-incompatible module %s%s "
1748 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1749 break;
1750 case export_gpl_future:
1751 warn("modpost: GPL-incompatible module %s%s "
1752 "uses future GPL-only symbol '%s'\n", m, e, s);
1753 break;
1754 case export_plain:
1755 case export_unused:
1756 case export_unknown:
1757 /* ignore */
1758 break;
1762 static void check_for_unused(enum export exp, const char *m, const char *s)
1764 const char *e = is_vmlinux(m) ?"":".ko";
1766 switch (exp) {
1767 case export_unused:
1768 case export_unused_gpl:
1769 warn("modpost: module %s%s "
1770 "uses symbol '%s' marked UNUSED\n", m, e, s);
1771 break;
1772 default:
1773 /* ignore */
1774 break;
1778 static void check_exports(struct module *mod)
1780 struct symbol *s, *exp;
1782 for (s = mod->unres; s; s = s->next) {
1783 const char *basename;
1784 exp = find_symbol(s->name);
1785 if (!exp || exp->module == mod)
1786 continue;
1787 basename = strrchr(mod->name, '/');
1788 if (basename)
1789 basename++;
1790 else
1791 basename = mod->name;
1792 if (!mod->gpl_compatible)
1793 check_for_gpl_usage(exp->export, basename, exp->name);
1794 check_for_unused(exp->export, basename, exp->name);
1799 * Header for the generated file
1801 static void add_header(struct buffer *b, struct module *mod)
1803 buf_printf(b, "#include <linux/module.h>\n");
1804 buf_printf(b, "#include <linux/vermagic.h>\n");
1805 buf_printf(b, "#include <linux/compiler.h>\n");
1806 buf_printf(b, "\n");
1807 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1808 buf_printf(b, "\n");
1809 buf_printf(b, "struct module __this_module\n");
1810 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1811 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1812 if (mod->has_init)
1813 buf_printf(b, " .init = init_module,\n");
1814 if (mod->has_cleanup)
1815 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1816 " .exit = cleanup_module,\n"
1817 "#endif\n");
1818 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1819 buf_printf(b, "};\n");
1822 static void add_staging_flag(struct buffer *b, const char *name)
1824 static const char *staging_dir = "drivers/staging";
1826 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1827 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1831 * Record CRCs for unresolved symbols
1833 static int add_versions(struct buffer *b, struct module *mod)
1835 struct symbol *s, *exp;
1836 int err = 0;
1838 for (s = mod->unres; s; s = s->next) {
1839 exp = find_symbol(s->name);
1840 if (!exp || exp->module == mod) {
1841 if (have_vmlinux && !s->weak) {
1842 if (warn_unresolved) {
1843 warn("\"%s\" [%s.ko] undefined!\n",
1844 s->name, mod->name);
1845 } else {
1846 merror("\"%s\" [%s.ko] undefined!\n",
1847 s->name, mod->name);
1848 err = 1;
1851 continue;
1853 s->module = exp->module;
1854 s->crc_valid = exp->crc_valid;
1855 s->crc = exp->crc;
1858 if (!modversions)
1859 return err;
1861 buf_printf(b, "\n");
1862 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1863 buf_printf(b, "__used\n");
1864 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1866 for (s = mod->unres; s; s = s->next) {
1867 if (!s->module)
1868 continue;
1869 if (!s->crc_valid) {
1870 warn("\"%s\" [%s.ko] has no CRC!\n",
1871 s->name, mod->name);
1872 continue;
1874 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1877 buf_printf(b, "};\n");
1879 return err;
1882 static void add_depends(struct buffer *b, struct module *mod,
1883 struct module *modules)
1885 struct symbol *s;
1886 struct module *m;
1887 int first = 1;
1889 for (m = modules; m; m = m->next)
1890 m->seen = is_vmlinux(m->name);
1892 buf_printf(b, "\n");
1893 buf_printf(b, "static const char __module_depends[]\n");
1894 buf_printf(b, "__used\n");
1895 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1896 buf_printf(b, "\"depends=");
1897 for (s = mod->unres; s; s = s->next) {
1898 const char *p;
1899 if (!s->module)
1900 continue;
1902 if (s->module->seen)
1903 continue;
1905 s->module->seen = 1;
1906 p = strrchr(s->module->name, '/');
1907 if (p)
1908 p++;
1909 else
1910 p = s->module->name;
1911 buf_printf(b, "%s%s", first ? "" : ",", p);
1912 first = 0;
1914 buf_printf(b, "\";\n");
1917 static void add_srcversion(struct buffer *b, struct module *mod)
1919 if (mod->srcversion[0]) {
1920 buf_printf(b, "\n");
1921 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1922 mod->srcversion);
1926 static void write_if_changed(struct buffer *b, const char *fname)
1928 char *tmp;
1929 FILE *file;
1930 struct stat st;
1932 file = fopen(fname, "r");
1933 if (!file)
1934 goto write;
1936 if (fstat(fileno(file), &st) < 0)
1937 goto close_write;
1939 if (st.st_size != b->pos)
1940 goto close_write;
1942 tmp = NOFAIL(malloc(b->pos));
1943 if (fread(tmp, 1, b->pos, file) != b->pos)
1944 goto free_write;
1946 if (memcmp(tmp, b->p, b->pos) != 0)
1947 goto free_write;
1949 free(tmp);
1950 fclose(file);
1951 return;
1953 free_write:
1954 free(tmp);
1955 close_write:
1956 fclose(file);
1957 write:
1958 file = fopen(fname, "w");
1959 if (!file) {
1960 perror(fname);
1961 exit(1);
1963 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1964 perror(fname);
1965 exit(1);
1967 fclose(file);
1970 /* parse Module.symvers file. line format:
1971 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1973 static void read_dump(const char *fname, unsigned int kernel)
1975 unsigned long size, pos = 0;
1976 void *file = grab_file(fname, &size);
1977 char *line;
1979 if (!file)
1980 /* No symbol versions, silently ignore */
1981 return;
1983 while ((line = get_next_line(&pos, file, size))) {
1984 char *symname, *modname, *d, *export, *end;
1985 unsigned int crc;
1986 struct module *mod;
1987 struct symbol *s;
1989 if (!(symname = strchr(line, '\t')))
1990 goto fail;
1991 *symname++ = '\0';
1992 if (!(modname = strchr(symname, '\t')))
1993 goto fail;
1994 *modname++ = '\0';
1995 if ((export = strchr(modname, '\t')) != NULL)
1996 *export++ = '\0';
1997 if (export && ((end = strchr(export, '\t')) != NULL))
1998 *end = '\0';
1999 crc = strtoul(line, &d, 16);
2000 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2001 goto fail;
2002 mod = find_module(modname);
2003 if (!mod) {
2004 if (is_vmlinux(modname))
2005 have_vmlinux = 1;
2006 mod = new_module(modname);
2007 mod->skip = 1;
2009 s = sym_add_exported(symname, mod, export_no(export));
2010 s->kernel = kernel;
2011 s->preloaded = 1;
2012 sym_update_crc(symname, mod, crc, export_no(export));
2014 return;
2015 fail:
2016 fatal("parse error in symbol dump file\n");
2019 /* For normal builds always dump all symbols.
2020 * For external modules only dump symbols
2021 * that are not read from kernel Module.symvers.
2023 static int dump_sym(struct symbol *sym)
2025 if (!external_module)
2026 return 1;
2027 if (sym->vmlinux || sym->kernel)
2028 return 0;
2029 return 1;
2032 static void write_dump(const char *fname)
2034 struct buffer buf = { };
2035 struct symbol *symbol;
2036 int n;
2038 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2039 symbol = symbolhash[n];
2040 while (symbol) {
2041 if (dump_sym(symbol))
2042 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2043 symbol->crc, symbol->name,
2044 symbol->module->name,
2045 export_str(symbol->export));
2046 symbol = symbol->next;
2049 write_if_changed(&buf, fname);
2052 struct ext_sym_list {
2053 struct ext_sym_list *next;
2054 const char *file;
2057 int main(int argc, char **argv)
2059 struct module *mod;
2060 struct buffer buf = { };
2061 char *kernel_read = NULL, *module_read = NULL;
2062 char *dump_write = NULL;
2063 int opt;
2064 int err;
2065 struct ext_sym_list *extsym_iter;
2066 struct ext_sym_list *extsym_start = NULL;
2068 while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2069 switch (opt) {
2070 case 'i':
2071 kernel_read = optarg;
2072 break;
2073 case 'I':
2074 module_read = optarg;
2075 external_module = 1;
2076 break;
2077 case 'c':
2078 cross_build = 1;
2079 break;
2080 case 'e':
2081 external_module = 1;
2082 extsym_iter =
2083 NOFAIL(malloc(sizeof(*extsym_iter)));
2084 extsym_iter->next = extsym_start;
2085 extsym_iter->file = optarg;
2086 extsym_start = extsym_iter;
2087 break;
2088 case 'm':
2089 modversions = 1;
2090 break;
2091 case 'o':
2092 dump_write = optarg;
2093 break;
2094 case 'a':
2095 all_versions = 1;
2096 break;
2097 case 's':
2098 vmlinux_section_warnings = 0;
2099 break;
2100 case 'S':
2101 sec_mismatch_verbose = 0;
2102 break;
2103 case 'w':
2104 warn_unresolved = 1;
2105 break;
2106 default:
2107 exit(1);
2111 if (kernel_read)
2112 read_dump(kernel_read, 1);
2113 if (module_read)
2114 read_dump(module_read, 0);
2115 while (extsym_start) {
2116 read_dump(extsym_start->file, 0);
2117 extsym_iter = extsym_start->next;
2118 free(extsym_start);
2119 extsym_start = extsym_iter;
2122 while (optind < argc)
2123 read_symbols(argv[optind++]);
2125 for (mod = modules; mod; mod = mod->next) {
2126 if (mod->skip)
2127 continue;
2128 check_exports(mod);
2131 err = 0;
2133 for (mod = modules; mod; mod = mod->next) {
2134 char fname[strlen(mod->name) + 10];
2136 if (mod->skip)
2137 continue;
2139 buf.pos = 0;
2141 add_header(&buf, mod);
2142 add_staging_flag(&buf, mod->name);
2143 err |= add_versions(&buf, mod);
2144 add_depends(&buf, mod, modules);
2145 add_moddevtable(&buf, mod);
2146 add_srcversion(&buf, mod);
2148 sprintf(fname, "%s.mod.c", mod->name);
2149 write_if_changed(&buf, fname);
2152 if (dump_write)
2153 write_dump(dump_write);
2154 if (sec_mismatch_count && !sec_mismatch_verbose)
2155 warn("modpost: Found %d section mismatch(es).\n"
2156 "To see full details build your kernel with:\n"
2157 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2158 sec_mismatch_count);
2160 return err;