projects/linux·blob v5.12-rc5 · refs

2614 lines · 66.8 KiB

1/* Postprocess module symbol versions
2 *
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
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * Usage: modpost vmlinux module1.o module2.o ...
12 */
13
14#define _GNU_SOURCE
15#include <elf.h>
16#include <stdio.h>
17#include <ctype.h>
18#include <string.h>
19#include <limits.h>
20#include <errno.h>
21#include "modpost.h"
22#include "../../include/linux/license.h"
23
24/* Are we using CONFIG_MODVERSIONS? */
25static int modversions = 0;
26/* Warn about undefined symbols? (do so if we have vmlinux) */
27static int have_vmlinux = 0;
28/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
29static int all_versions = 0;
30/* If we are modposting external module set to 1 */
31static int external_module = 0;
32/* Only warn about unresolved symbols */
33static int warn_unresolved = 0;
34/* How a symbol is exported */
35static int sec_mismatch_count = 0;
36static int sec_mismatch_warn_only = true;
37/* ignore missing files */
38static int ignore_missing_files;
39/* If set to 1, only warn (instead of error) about missing ns imports */
40static int allow_missing_ns_imports;
41
42static bool error_occurred;
43
44enum export {
45 export_plain,
46 export_gpl,
47 export_unknown
48};
49
50/* In kernel, this size is defined in linux/module.h;
51 * here we use Elf_Addr instead of long for covering cross-compile
52 */
53
54#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
55
56void __attribute__((format(printf, 2, 3)))
57modpost_log(enum loglevel loglevel, const char *fmt, ...)
58{
59 va_list arglist;
60
61 switch (loglevel) {
62 case LOG_WARN:
63 fprintf(stderr, "WARNING: ");
64 break;
65 case LOG_ERROR:
66 fprintf(stderr, "ERROR: ");
67 break;
68 case LOG_FATAL:
69 fprintf(stderr, "FATAL: ");
70 break;
71 default: /* invalid loglevel, ignore */
72 break;
73 }
74
75 fprintf(stderr, "modpost: ");
76
77 va_start(arglist, fmt);
78 vfprintf(stderr, fmt, arglist);
79 va_end(arglist);
80
81 if (loglevel == LOG_FATAL)
82 exit(1);
83 if (loglevel == LOG_ERROR)
84 error_occurred = true;
85}
86
87void *do_nofail(void *ptr, const char *expr)
88{
89 if (!ptr)
90 fatal("Memory allocation failure: %s.\n", expr);
91
92 return ptr;
93}
94
95char *read_text_file(const char *filename)
96{
97 struct stat st;
98 size_t nbytes;
99 int fd;
100 char *buf;
101
102 fd = open(filename, O_RDONLY);
103 if (fd < 0) {
104 perror(filename);
105 exit(1);
106 }
107
108 if (fstat(fd, &st) < 0) {
109 perror(filename);
110 exit(1);
111 }
112
113 buf = NOFAIL(malloc(st.st_size + 1));
114
115 nbytes = st.st_size;
116
117 while (nbytes) {
118 ssize_t bytes_read;
119
120 bytes_read = read(fd, buf, nbytes);
121 if (bytes_read < 0) {
122 perror(filename);
123 exit(1);
124 }
125
126 nbytes -= bytes_read;
127 }
128 buf[st.st_size] = '\0';
129
130 close(fd);
131
132 return buf;
133}
134
135char *get_line(char **stringp)
136{
137 char *orig = *stringp, *next;
138
139 /* do not return the unwanted extra line at EOF */
140 if (!orig || *orig == '\0')
141 return NULL;
142
143 /* don't use strsep here, it is not available everywhere */
144 next = strchr(orig, '\n');
145 if (next)
146 *next++ = '\0';
147
148 *stringp = next;
149
150 return orig;
151}
152
153/* A list of all modules we processed */
154static struct module *modules;
155
156static struct module *find_module(const char *modname)
157{
158 struct module *mod;
159
160 for (mod = modules; mod; mod = mod->next)
161 if (strcmp(mod->name, modname) == 0)
162 break;
163 return mod;
164}
165
166static struct module *new_module(const char *modname)
167{
168 struct module *mod;
169
170 mod = NOFAIL(malloc(sizeof(*mod) + strlen(modname) + 1));
171 memset(mod, 0, sizeof(*mod));
172
173 /* add to list */
174 strcpy(mod->name, modname);
175 mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0);
176 mod->gpl_compatible = -1;
177 mod->next = modules;
178 modules = mod;
179
180 if (mod->is_vmlinux)
181 have_vmlinux = 1;
182
183 return mod;
184}
185
186/* A hash of all exported symbols,
187 * struct symbol is also used for lists of unresolved symbols */
188
189#define SYMBOL_HASH_SIZE 1024
190
191struct symbol {
192 struct symbol *next;
193 struct module *module;
194 unsigned int crc;
195 int crc_valid;
196 char *namespace;
197 unsigned int weak:1;
198 unsigned int is_static:1; /* 1 if symbol is not global */
199 enum export export; /* Type of export */
200 char name[];
201};
202
203static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
204
205/* This is based on the hash agorithm from gdbm, via tdb */
206static inline unsigned int tdb_hash(const char *name)
207{
208 unsigned value; /* Used to compute the hash value. */
209 unsigned i; /* Used to cycle through random values. */
210
211 /* Set the initial value from the key size. */
212 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
213 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
214
215 return (1103515243 * value + 12345);
216}
217
218/**
219 * Allocate a new symbols for use in the hash of exported symbols or
220 * the list of unresolved symbols per module
221 **/
222static struct symbol *alloc_symbol(const char *name, unsigned int weak,
223 struct symbol *next)
224{
225 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
226
227 memset(s, 0, sizeof(*s));
228 strcpy(s->name, name);
229 s->weak = weak;
230 s->next = next;
231 s->is_static = 1;
232 return s;
233}
234
235/* For the hash of exported symbols */
236static struct symbol *new_symbol(const char *name, struct module *module,
237 enum export export)
238{
239 unsigned int hash;
240
241 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
242 symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
243
244 return symbolhash[hash];
245}
246
247static struct symbol *find_symbol(const char *name)
248{
249 struct symbol *s;
250
251 /* For our purposes, .foo matches foo. PPC64 needs this. */
252 if (name[0] == '.')
253 name++;
254
255 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
256 if (strcmp(s->name, name) == 0)
257 return s;
258 }
259 return NULL;
260}
261
262static bool contains_namespace(struct namespace_list *list,
263 const char *namespace)
264{
265 for (; list; list = list->next)
266 if (!strcmp(list->namespace, namespace))
267 return true;
268
269 return false;
270}
271
272static void add_namespace(struct namespace_list **list, const char *namespace)
273{
274 struct namespace_list *ns_entry;
275
276 if (!contains_namespace(*list, namespace)) {
277 ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
278 strlen(namespace) + 1));
279 strcpy(ns_entry->namespace, namespace);
280 ns_entry->next = *list;
281 *list = ns_entry;
282 }
283}
284
285static bool module_imports_namespace(struct module *module,
286 const char *namespace)
287{
288 return contains_namespace(module->imported_namespaces, namespace);
289}
290
291static const struct {
292 const char *str;
293 enum export export;
294} export_list[] = {
295 { .str = "EXPORT_SYMBOL", .export = export_plain },
296 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
297 { .str = "(unknown)", .export = export_unknown },
298};
299
300
301static const char *export_str(enum export ex)
302{
303 return export_list[ex].str;
304}
305
306static enum export export_no(const char *s)
307{
308 int i;
309
310 if (!s)
311 return export_unknown;
312 for (i = 0; export_list[i].export != export_unknown; i++) {
313 if (strcmp(export_list[i].str, s) == 0)
314 return export_list[i].export;
315 }
316 return export_unknown;
317}
318
319static void *sym_get_data_by_offset(const struct elf_info *info,
320 unsigned int secindex, unsigned long offset)
321{
322 Elf_Shdr *sechdr = &info->sechdrs[secindex];
323
324 if (info->hdr->e_type != ET_REL)
325 offset -= sechdr->sh_addr;
326
327 return (void *)info->hdr + sechdr->sh_offset + offset;
328}
329
330static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
331{
332 return sym_get_data_by_offset(info, get_secindex(info, sym),
333 sym->st_value);
334}
335
336static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
337{
338 return sym_get_data_by_offset(info, info->secindex_strings,
339 sechdr->sh_name);
340}
341
342static const char *sec_name(const struct elf_info *info, int secindex)
343{
344 return sech_name(info, &info->sechdrs[secindex]);
345}
346
347#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
348
349static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
350{
351 const char *secname = sec_name(elf, sec);
352
353 if (strstarts(secname, "___ksymtab+"))
354 return export_plain;
355 else if (strstarts(secname, "___ksymtab_gpl+"))
356 return export_gpl;
357 else
358 return export_unknown;
359}
360
361static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
362{
363 if (sec == elf->export_sec)
364 return export_plain;
365 else if (sec == elf->export_gpl_sec)
366 return export_gpl;
367 else
368 return export_unknown;
369}
370
371static const char *namespace_from_kstrtabns(const struct elf_info *info,
372 const Elf_Sym *sym)
373{
374 const char *value = sym_get_data(info, sym);
375 return value[0] ? value : NULL;
376}
377
378static void sym_update_namespace(const char *symname, const char *namespace)
379{
380 struct symbol *s = find_symbol(symname);
381
382 /*
383 * That symbol should have been created earlier and thus this is
384 * actually an assertion.
385 */
386 if (!s) {
387 error("Could not update namespace(%s) for symbol %s\n",
388 namespace, symname);
389 return;
390 }
391
392 free(s->namespace);
393 s->namespace =
394 namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
395}
396
397/**
398 * Add an exported symbol - it may have already been added without a
399 * CRC, in this case just update the CRC
400 **/
401static struct symbol *sym_add_exported(const char *name, struct module *mod,
402 enum export export)
403{
404 struct symbol *s = find_symbol(name);
405
406 if (!s) {
407 s = new_symbol(name, mod, export);
408 } else if (!external_module || s->module->is_vmlinux ||
409 s->module == mod) {
410 warn("%s: '%s' exported twice. Previous export was in %s%s\n",
411 mod->name, name, s->module->name,
412 s->module->is_vmlinux ? "" : ".ko");
413 return s;
414 }
415
416 s->module = mod;
417 s->export = export;
418 return s;
419}
420
421static void sym_set_crc(const char *name, unsigned int crc)
422{
423 struct symbol *s = find_symbol(name);
424
425 /*
426 * Ignore stand-alone __crc_*, which might be auto-generated symbols
427 * such as __*_veneer in ARM ELF.
428 */
429 if (!s)
430 return;
431
432 s->crc = crc;
433 s->crc_valid = 1;
434}
435
436static void *grab_file(const char *filename, size_t *size)
437{
438 struct stat st;
439 void *map = MAP_FAILED;
440 int fd;
441
442 fd = open(filename, O_RDONLY);
443 if (fd < 0)
444 return NULL;
445 if (fstat(fd, &st))
446 goto failed;
447
448 *size = st.st_size;
449 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
450
451failed:
452 close(fd);
453 if (map == MAP_FAILED)
454 return NULL;
455 return map;
456}
457
458static void release_file(void *file, size_t size)
459{
460 munmap(file, size);
461}
462
463static int parse_elf(struct elf_info *info, const char *filename)
464{
465 unsigned int i;
466 Elf_Ehdr *hdr;
467 Elf_Shdr *sechdrs;
468 Elf_Sym *sym;
469 const char *secstrings;
470 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
471
472 hdr = grab_file(filename, &info->size);
473 if (!hdr) {
474 if (ignore_missing_files) {
475 fprintf(stderr, "%s: %s (ignored)\n", filename,
476 strerror(errno));
477 return 0;
478 }
479 perror(filename);
480 exit(1);
481 }
482 info->hdr = hdr;
483 if (info->size < sizeof(*hdr)) {
484 /* file too small, assume this is an empty .o file */
485 return 0;
486 }
487 /* Is this a valid ELF file? */
488 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
489 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
490 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
491 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
492 /* Not an ELF file - silently ignore it */
493 return 0;
494 }
495 /* Fix endianness in ELF header */
496 hdr->e_type = TO_NATIVE(hdr->e_type);
497 hdr->e_machine = TO_NATIVE(hdr->e_machine);
498 hdr->e_version = TO_NATIVE(hdr->e_version);
499 hdr->e_entry = TO_NATIVE(hdr->e_entry);
500 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
501 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
502 hdr->e_flags = TO_NATIVE(hdr->e_flags);
503 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
504 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
505 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
506 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
507 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
508 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
509 sechdrs = (void *)hdr + hdr->e_shoff;
510 info->sechdrs = sechdrs;
511
512 /* Check if file offset is correct */
513 if (hdr->e_shoff > info->size) {
514 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
515 (unsigned long)hdr->e_shoff, filename, info->size);
516 return 0;
517 }
518
519 if (hdr->e_shnum == SHN_UNDEF) {
520 /*
521 * There are more than 64k sections,
522 * read count from .sh_size.
523 */
524 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
525 }
526 else {
527 info->num_sections = hdr->e_shnum;
528 }
529 if (hdr->e_shstrndx == SHN_XINDEX) {
530 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
531 }
532 else {
533 info->secindex_strings = hdr->e_shstrndx;
534 }
535
536 /* Fix endianness in section headers */
537 for (i = 0; i < info->num_sections; i++) {
538 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
539 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
540 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
541 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
542 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
543 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
544 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
545 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
546 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
547 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
548 }
549 /* Find symbol table. */
550 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
551 for (i = 1; i < info->num_sections; i++) {
552 const char *secname;
553 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
554
555 if (!nobits && sechdrs[i].sh_offset > info->size) {
556 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
557 "sizeof(*hrd)=%zu\n", filename,
558 (unsigned long)sechdrs[i].sh_offset,
559 sizeof(*hdr));
560 return 0;
561 }
562 secname = secstrings + sechdrs[i].sh_name;
563 if (strcmp(secname, ".modinfo") == 0) {
564 if (nobits)
565 fatal("%s has NOBITS .modinfo\n", filename);
566 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
567 info->modinfo_len = sechdrs[i].sh_size;
568 } else if (strcmp(secname, "__ksymtab") == 0)
569 info->export_sec = i;
570 else if (strcmp(secname, "__ksymtab_gpl") == 0)
571 info->export_gpl_sec = i;
572
573 if (sechdrs[i].sh_type == SHT_SYMTAB) {
574 unsigned int sh_link_idx;
575 symtab_idx = i;
576 info->symtab_start = (void *)hdr +
577 sechdrs[i].sh_offset;
578 info->symtab_stop = (void *)hdr +
579 sechdrs[i].sh_offset + sechdrs[i].sh_size;
580 sh_link_idx = sechdrs[i].sh_link;
581 info->strtab = (void *)hdr +
582 sechdrs[sh_link_idx].sh_offset;
583 }
584
585 /* 32bit section no. table? ("more than 64k sections") */
586 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
587 symtab_shndx_idx = i;
588 info->symtab_shndx_start = (void *)hdr +
589 sechdrs[i].sh_offset;
590 info->symtab_shndx_stop = (void *)hdr +
591 sechdrs[i].sh_offset + sechdrs[i].sh_size;
592 }
593 }
594 if (!info->symtab_start)
595 fatal("%s has no symtab?\n", filename);
596
597 /* Fix endianness in symbols */
598 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
599 sym->st_shndx = TO_NATIVE(sym->st_shndx);
600 sym->st_name = TO_NATIVE(sym->st_name);
601 sym->st_value = TO_NATIVE(sym->st_value);
602 sym->st_size = TO_NATIVE(sym->st_size);
603 }
604
605 if (symtab_shndx_idx != ~0U) {
606 Elf32_Word *p;
607 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
608 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
609 filename, sechdrs[symtab_shndx_idx].sh_link,
610 symtab_idx);
611 /* Fix endianness */
612 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
613 p++)
614 *p = TO_NATIVE(*p);
615 }
616
617 return 1;
618}
619
620static void parse_elf_finish(struct elf_info *info)
621{
622 release_file(info->hdr, info->size);
623}
624
625static int ignore_undef_symbol(struct elf_info *info, const char *symname)
626{
627 /* ignore __this_module, it will be resolved shortly */
628 if (strcmp(symname, "__this_module") == 0)
629 return 1;
630 /* ignore global offset table */
631 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
632 return 1;
633 if (info->hdr->e_machine == EM_PPC)
634 /* Special register function linked on all modules during final link of .ko */
635 if (strstarts(symname, "_restgpr_") ||
636 strstarts(symname, "_savegpr_") ||
637 strstarts(symname, "_rest32gpr_") ||
638 strstarts(symname, "_save32gpr_") ||
639 strstarts(symname, "_restvr_") ||
640 strstarts(symname, "_savevr_"))
641 return 1;
642 if (info->hdr->e_machine == EM_PPC64)
643 /* Special register function linked on all modules during final link of .ko */
644 if (strstarts(symname, "_restgpr0_") ||
645 strstarts(symname, "_savegpr0_") ||
646 strstarts(symname, "_restvr_") ||
647 strstarts(symname, "_savevr_") ||
648 strcmp(symname, ".TOC.") == 0)
649 return 1;
650 /* Do not ignore this symbol */
651 return 0;
652}
653
654static void handle_modversion(const struct module *mod,
655 const struct elf_info *info,
656 const Elf_Sym *sym, const char *symname)
657{
658 unsigned int crc;
659
660 if (sym->st_shndx == SHN_UNDEF) {
661 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
662 symname, mod->name, mod->is_vmlinux ? "" : ".ko");
663 return;
664 }
665
666 if (sym->st_shndx == SHN_ABS) {
667 crc = sym->st_value;
668 } else {
669 unsigned int *crcp;
670
671 /* symbol points to the CRC in the ELF object */
672 crcp = sym_get_data(info, sym);
673 crc = TO_NATIVE(*crcp);
674 }
675 sym_set_crc(symname, crc);
676}
677
678static void handle_symbol(struct module *mod, struct elf_info *info,
679 const Elf_Sym *sym, const char *symname)
680{
681 enum export export;
682 const char *name;
683
684 if (strstarts(symname, "__ksymtab"))
685 export = export_from_secname(info, get_secindex(info, sym));
686 else
687 export = export_from_sec(info, get_secindex(info, sym));
688
689 switch (sym->st_shndx) {
690 case SHN_COMMON:
691 if (strstarts(symname, "__gnu_lto_")) {
692 /* Should warn here, but modpost runs before the linker */
693 } else
694 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
695 break;
696 case SHN_UNDEF:
697 /* undefined symbol */
698 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
699 ELF_ST_BIND(sym->st_info) != STB_WEAK)
700 break;
701 if (ignore_undef_symbol(info, symname))
702 break;
703 if (info->hdr->e_machine == EM_SPARC ||
704 info->hdr->e_machine == EM_SPARCV9) {
705 /* Ignore register directives. */
706 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
707 break;
708 if (symname[0] == '.') {
709 char *munged = NOFAIL(strdup(symname));
710 munged[0] = '_';
711 munged[1] = toupper(munged[1]);
712 symname = munged;
713 }
714 }
715
716 mod->unres = alloc_symbol(symname,
717 ELF_ST_BIND(sym->st_info) == STB_WEAK,
718 mod->unres);
719 break;
720 default:
721 /* All exported symbols */
722 if (strstarts(symname, "__ksymtab_")) {
723 name = symname + strlen("__ksymtab_");
724 sym_add_exported(name, mod, export);
725 }
726 if (strcmp(symname, "init_module") == 0)
727 mod->has_init = 1;
728 if (strcmp(symname, "cleanup_module") == 0)
729 mod->has_cleanup = 1;
730 break;
731 }
732}
733
734/**
735 * Parse tag=value strings from .modinfo section
736 **/
737static char *next_string(char *string, unsigned long *secsize)
738{
739 /* Skip non-zero chars */
740 while (string[0]) {
741 string++;
742 if ((*secsize)-- <= 1)
743 return NULL;
744 }
745
746 /* Skip any zero padding. */
747 while (!string[0]) {
748 string++;
749 if ((*secsize)-- <= 1)
750 return NULL;
751 }
752 return string;
753}
754
755static char *get_next_modinfo(struct elf_info *info, const char *tag,
756 char *prev)
757{
758 char *p;
759 unsigned int taglen = strlen(tag);
760 char *modinfo = info->modinfo;
761 unsigned long size = info->modinfo_len;
762
763 if (prev) {
764 size -= prev - modinfo;
765 modinfo = next_string(prev, &size);
766 }
767
768 for (p = modinfo; p; p = next_string(p, &size)) {
769 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
770 return p + taglen + 1;
771 }
772 return NULL;
773}
774
775static char *get_modinfo(struct elf_info *info, const char *tag)
776
777{
778 return get_next_modinfo(info, tag, NULL);
779}
780
781/**
782 * Test if string s ends in string sub
783 * return 0 if match
784 **/
785static int strrcmp(const char *s, const char *sub)
786{
787 int slen, sublen;
788
789 if (!s || !sub)
790 return 1;
791
792 slen = strlen(s);
793 sublen = strlen(sub);
794
795 if ((slen == 0) || (sublen == 0))
796 return 1;
797
798 if (sublen > slen)
799 return 1;
800
801 return memcmp(s + slen - sublen, sub, sublen);
802}
803
804static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
805{
806 if (sym)
807 return elf->strtab + sym->st_name;
808 else
809 return "(unknown)";
810}
811
812/* The pattern is an array of simple patterns.
813 * "foo" will match an exact string equal to "foo"
814 * "*foo" will match a string that ends with "foo"
815 * "foo*" will match a string that begins with "foo"
816 * "*foo*" will match a string that contains "foo"
817 */
818static int match(const char *sym, const char * const pat[])
819{
820 const char *p;
821 while (*pat) {
822 p = *pat++;
823 const char *endp = p + strlen(p) - 1;
824
825 /* "*foo*" */
826 if (*p == '*' && *endp == '*') {
827 char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
828 char *here = strstr(sym, bare);
829
830 free(bare);
831 if (here != NULL)
832 return 1;
833 }
834 /* "*foo" */
835 else if (*p == '*') {
836 if (strrcmp(sym, p + 1) == 0)
837 return 1;
838 }
839 /* "foo*" */
840 else if (*endp == '*') {
841 if (strncmp(sym, p, strlen(p) - 1) == 0)
842 return 1;
843 }
844 /* no wildcards */
845 else {
846 if (strcmp(p, sym) == 0)
847 return 1;
848 }
849 }
850 /* no match */
851 return 0;
852}
853
854/* sections that we do not want to do full section mismatch check on */
855static const char *const section_white_list[] =
856{
857 ".comment*",
858 ".debug*",
859 ".cranges", /* sh64 */
860 ".zdebug*", /* Compressed debug sections. */
861 ".GCC.command.line", /* record-gcc-switches */
862 ".mdebug*", /* alpha, score, mips etc. */
863 ".pdr", /* alpha, score, mips etc. */
864 ".stab*",
865 ".note*",
866 ".got*",
867 ".toc*",
868 ".xt.prop", /* xtensa */
869 ".xt.lit", /* xtensa */
870 ".arcextmap*", /* arc */
871 ".gnu.linkonce.arcext*", /* arc : modules */
872 ".cmem*", /* EZchip */
873 ".fmt_slot*", /* EZchip */
874 ".gnu.lto*",
875 ".discard.*",
876 NULL
877};
878
879/*
880 * This is used to find sections missing the SHF_ALLOC flag.
881 * The cause of this is often a section specified in assembler
882 * without "ax" / "aw".
883 */
884static void check_section(const char *modname, struct elf_info *elf,
885 Elf_Shdr *sechdr)
886{
887 const char *sec = sech_name(elf, sechdr);
888
889 if (sechdr->sh_type == SHT_PROGBITS &&
890 !(sechdr->sh_flags & SHF_ALLOC) &&
891 !match(sec, section_white_list)) {
892 warn("%s (%s): unexpected non-allocatable section.\n"
893 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
894 "Note that for example <linux/init.h> contains\n"
895 "section definitions for use in .S files.\n\n",
896 modname, sec);
897 }
898}
899
900
901
902#define ALL_INIT_DATA_SECTIONS \
903 ".init.setup", ".init.rodata", ".meminit.rodata", \
904 ".init.data", ".meminit.data"
905#define ALL_EXIT_DATA_SECTIONS \
906 ".exit.data", ".memexit.data"
907
908#define ALL_INIT_TEXT_SECTIONS \
909 ".init.text", ".meminit.text"
910#define ALL_EXIT_TEXT_SECTIONS \
911 ".exit.text", ".memexit.text"
912
913#define ALL_PCI_INIT_SECTIONS \
914 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
915 ".pci_fixup_enable", ".pci_fixup_resume", \
916 ".pci_fixup_resume_early", ".pci_fixup_suspend"
917
918#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
919#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
920
921#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
922#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
923
924#define DATA_SECTIONS ".data", ".data.rel"
925#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
926 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
927#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
928 ".fixup", ".entry.text", ".exception.text", ".text.*", \
929 ".coldtext"
930
931#define INIT_SECTIONS ".init.*"
932#define MEM_INIT_SECTIONS ".meminit.*"
933
934#define EXIT_SECTIONS ".exit.*"
935#define MEM_EXIT_SECTIONS ".memexit.*"
936
937#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
938 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
939
940/* init data sections */
941static const char *const init_data_sections[] =
942 { ALL_INIT_DATA_SECTIONS, NULL };
943
944/* all init sections */
945static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
946
947/* All init and exit sections (code + data) */
948static const char *const init_exit_sections[] =
949 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
950
951/* all text sections */
952static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
953
954/* data section */
955static const char *const data_sections[] = { DATA_SECTIONS, NULL };
956
957
958/* symbols in .data that may refer to init/exit sections */
959#define DEFAULT_SYMBOL_WHITE_LIST \
960 "*driver", \
961 "*_template", /* scsi uses *_template a lot */ \
962 "*_timer", /* arm uses ops structures named _timer a lot */ \
963 "*_sht", /* scsi also used *_sht to some extent */ \
964 "*_ops", \
965 "*_probe", \
966 "*_probe_one", \
967 "*_console"
968
969static const char *const head_sections[] = { ".head.text*", NULL };
970static const char *const linker_symbols[] =
971 { "__init_begin", "_sinittext", "_einittext", NULL };
972static const char *const optim_symbols[] = { "*.constprop.*", NULL };
973
974enum mismatch {
975 TEXT_TO_ANY_INIT,
976 DATA_TO_ANY_INIT,
977 TEXT_TO_ANY_EXIT,
978 DATA_TO_ANY_EXIT,
979 XXXINIT_TO_SOME_INIT,
980 XXXEXIT_TO_SOME_EXIT,
981 ANY_INIT_TO_ANY_EXIT,
982 ANY_EXIT_TO_ANY_INIT,
983 EXPORT_TO_INIT_EXIT,
984 EXTABLE_TO_NON_TEXT,
985};
986
987/**
988 * Describe how to match sections on different criterias:
989 *
990 * @fromsec: Array of sections to be matched.
991 *
992 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
993 * this array is forbidden (black-list). Can be empty.
994 *
995 * @good_tosec: Relocations applied to a section in @fromsec must be
996 * targetting sections in this array (white-list). Can be empty.
997 *
998 * @mismatch: Type of mismatch.
999 *
1000 * @symbol_white_list: Do not match a relocation to a symbol in this list
1001 * even if it is targetting a section in @bad_to_sec.
1002 *
1003 * @handler: Specific handler to call when a match is found. If NULL,
1004 * default_mismatch_handler() will be called.
1005 *
1006 */
1007struct sectioncheck {
1008 const char *fromsec[20];
1009 const char *bad_tosec[20];
1010 const char *good_tosec[20];
1011 enum mismatch mismatch;
1012 const char *symbol_white_list[20];
1013 void (*handler)(const char *modname, struct elf_info *elf,
1014 const struct sectioncheck* const mismatch,
1015 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1016
1017};
1018
1019static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1020 const struct sectioncheck* const mismatch,
1021 Elf_Rela *r, Elf_Sym *sym,
1022 const char *fromsec);
1023
1024static const struct sectioncheck sectioncheck[] = {
1025/* Do not reference init/exit code/data from
1026 * normal code and data
1027 */
1028{
1029 .fromsec = { TEXT_SECTIONS, NULL },
1030 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1031 .mismatch = TEXT_TO_ANY_INIT,
1032 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1033},
1034{
1035 .fromsec = { DATA_SECTIONS, NULL },
1036 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1037 .mismatch = DATA_TO_ANY_INIT,
1038 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1039},
1040{
1041 .fromsec = { DATA_SECTIONS, NULL },
1042 .bad_tosec = { INIT_SECTIONS, NULL },
1043 .mismatch = DATA_TO_ANY_INIT,
1044 .symbol_white_list = {
1045 "*_template", "*_timer", "*_sht", "*_ops",
1046 "*_probe", "*_probe_one", "*_console", NULL
1047 },
1048},
1049{
1050 .fromsec = { TEXT_SECTIONS, NULL },
1051 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1052 .mismatch = TEXT_TO_ANY_EXIT,
1053 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1054},
1055{
1056 .fromsec = { DATA_SECTIONS, NULL },
1057 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1058 .mismatch = DATA_TO_ANY_EXIT,
1059 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1060},
1061/* Do not reference init code/data from meminit code/data */
1062{
1063 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1064 .bad_tosec = { INIT_SECTIONS, NULL },
1065 .mismatch = XXXINIT_TO_SOME_INIT,
1066 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1067},
1068/* Do not reference exit code/data from memexit code/data */
1069{
1070 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1071 .bad_tosec = { EXIT_SECTIONS, NULL },
1072 .mismatch = XXXEXIT_TO_SOME_EXIT,
1073 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1074},
1075/* Do not use exit code/data from init code */
1076{
1077 .fromsec = { ALL_INIT_SECTIONS, NULL },
1078 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1079 .mismatch = ANY_INIT_TO_ANY_EXIT,
1080 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1081},
1082/* Do not use init code/data from exit code */
1083{
1084 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1085 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1086 .mismatch = ANY_EXIT_TO_ANY_INIT,
1087 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1088},
1089{
1090 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1091 .bad_tosec = { INIT_SECTIONS, NULL },
1092 .mismatch = ANY_INIT_TO_ANY_EXIT,
1093 .symbol_white_list = { NULL },
1094},
1095/* Do not export init/exit functions or data */
1096{
1097 .fromsec = { "__ksymtab*", NULL },
1098 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1099 .mismatch = EXPORT_TO_INIT_EXIT,
1100 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1101},
1102{
1103 .fromsec = { "__ex_table", NULL },
1104 /* If you're adding any new black-listed sections in here, consider
1105 * adding a special 'printer' for them in scripts/check_extable.
1106 */
1107 .bad_tosec = { ".altinstr_replacement", NULL },
1108 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1109 .mismatch = EXTABLE_TO_NON_TEXT,
1110 .handler = extable_mismatch_handler,
1111}
1112};
1113
1114static const struct sectioncheck *section_mismatch(
1115 const char *fromsec, const char *tosec)
1116{
1117 int i;
1118 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1119 const struct sectioncheck *check = &sectioncheck[0];
1120
1121 /*
1122 * The target section could be the SHT_NUL section when we're
1123 * handling relocations to un-resolved symbols, trying to match it
1124 * doesn't make much sense and causes build failures on parisc
1125 * architectures.
1126 */
1127 if (*tosec == '\0')
1128 return NULL;
1129
1130 for (i = 0; i < elems; i++) {
1131 if (match(fromsec, check->fromsec)) {
1132 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1133 return check;
1134 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1135 return check;
1136 }
1137 check++;
1138 }
1139 return NULL;
1140}
1141
1142/**
1143 * Whitelist to allow certain references to pass with no warning.
1144 *
1145 * Pattern 1:
1146 * If a module parameter is declared __initdata and permissions=0
1147 * then this is legal despite the warning generated.
1148 * We cannot see value of permissions here, so just ignore
1149 * this pattern.
1150 * The pattern is identified by:
1151 * tosec = .init.data
1152 * fromsec = .data*
1153 * atsym =__param*
1154 *
1155 * Pattern 1a:
1156 * module_param_call() ops can refer to __init set function if permissions=0
1157 * The pattern is identified by:
1158 * tosec = .init.text
1159 * fromsec = .data*
1160 * atsym = __param_ops_*
1161 *
1162 * Pattern 2:
1163 * Many drivers utilise a *driver container with references to
1164 * add, remove, probe functions etc.
1165 * the pattern is identified by:
1166 * tosec = init or exit section
1167 * fromsec = data section
1168 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1169 * *probe_one, *_console, *_timer
1170 *
1171 * Pattern 3:
1172 * Whitelist all references from .head.text to any init section
1173 *
1174 * Pattern 4:
1175 * Some symbols belong to init section but still it is ok to reference
1176 * these from non-init sections as these symbols don't have any memory
1177 * allocated for them and symbol address and value are same. So even
1178 * if init section is freed, its ok to reference those symbols.
1179 * For ex. symbols marking the init section boundaries.
1180 * This pattern is identified by
1181 * refsymname = __init_begin, _sinittext, _einittext
1182 *
1183 * Pattern 5:
1184 * GCC may optimize static inlines when fed constant arg(s) resulting
1185 * in functions like cpumask_empty() -- generating an associated symbol
1186 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1187 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1188 * meaningless section warning. May need to add isra symbols too...
1189 * This pattern is identified by
1190 * tosec = init section
1191 * fromsec = text section
1192 * refsymname = *.constprop.*
1193 *
1194 * Pattern 6:
1195 * Hide section mismatch warnings for ELF local symbols. The goal
1196 * is to eliminate false positive modpost warnings caused by
1197 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1198 * Autogenerated symbol names bypass modpost's "Pattern 2"
1199 * whitelisting, which relies on pattern-matching against symbol
1200 * names to work. (One situation where gcc can autogenerate ELF
1201 * local symbols is when "-fsection-anchors" is used.)
1202 **/
1203static int secref_whitelist(const struct sectioncheck *mismatch,
1204 const char *fromsec, const char *fromsym,
1205 const char *tosec, const char *tosym)
1206{
1207 /* Check for pattern 1 */
1208 if (match(tosec, init_data_sections) &&
1209 match(fromsec, data_sections) &&
1210 strstarts(fromsym, "__param"))
1211 return 0;
1212
1213 /* Check for pattern 1a */
1214 if (strcmp(tosec, ".init.text") == 0 &&
1215 match(fromsec, data_sections) &&
1216 strstarts(fromsym, "__param_ops_"))
1217 return 0;
1218
1219 /* Check for pattern 2 */
1220 if (match(tosec, init_exit_sections) &&
1221 match(fromsec, data_sections) &&
1222 match(fromsym, mismatch->symbol_white_list))
1223 return 0;
1224
1225 /* Check for pattern 3 */
1226 if (match(fromsec, head_sections) &&
1227 match(tosec, init_sections))
1228 return 0;
1229
1230 /* Check for pattern 4 */
1231 if (match(tosym, linker_symbols))
1232 return 0;
1233
1234 /* Check for pattern 5 */
1235 if (match(fromsec, text_sections) &&
1236 match(tosec, init_sections) &&
1237 match(fromsym, optim_symbols))
1238 return 0;
1239
1240 /* Check for pattern 6 */
1241 if (strstarts(fromsym, ".L"))
1242 return 0;
1243
1244 return 1;
1245}
1246
1247static inline int is_arm_mapping_symbol(const char *str)
1248{
1249 return str[0] == '$' && strchr("axtd", str[1])
1250 && (str[2] == '\0' || str[2] == '.');
1251}
1252
1253/*
1254 * If there's no name there, ignore it; likewise, ignore it if it's
1255 * one of the magic symbols emitted used by current ARM tools.
1256 *
1257 * Otherwise if find_symbols_between() returns those symbols, they'll
1258 * fail the whitelist tests and cause lots of false alarms ... fixable
1259 * only by merging __exit and __init sections into __text, bloating
1260 * the kernel (which is especially evil on embedded platforms).
1261 */
1262static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1263{
1264 const char *name = elf->strtab + sym->st_name;
1265
1266 if (!name || !strlen(name))
1267 return 0;
1268 return !is_arm_mapping_symbol(name);
1269}
1270
1271/**
1272 * Find symbol based on relocation record info.
1273 * In some cases the symbol supplied is a valid symbol so
1274 * return refsym. If st_name != 0 we assume this is a valid symbol.
1275 * In other cases the symbol needs to be looked up in the symbol table
1276 * based on section and address.
1277 * **/
1278static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1279 Elf_Sym *relsym)
1280{
1281 Elf_Sym *sym;
1282 Elf_Sym *near = NULL;
1283 Elf64_Sword distance = 20;
1284 Elf64_Sword d;
1285 unsigned int relsym_secindex;
1286
1287 if (relsym->st_name != 0)
1288 return relsym;
1289
1290 relsym_secindex = get_secindex(elf, relsym);
1291 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1292 if (get_secindex(elf, sym) != relsym_secindex)
1293 continue;
1294 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1295 continue;
1296 if (!is_valid_name(elf, sym))
1297 continue;
1298 if (sym->st_value == addr)
1299 return sym;
1300 /* Find a symbol nearby - addr are maybe negative */
1301 d = sym->st_value - addr;
1302 if (d < 0)
1303 d = addr - sym->st_value;
1304 if (d < distance) {
1305 distance = d;
1306 near = sym;
1307 }
1308 }
1309 /* We need a close match */
1310 if (distance < 20)
1311 return near;
1312 else
1313 return NULL;
1314}
1315
1316/*
1317 * Find symbols before or equal addr and after addr - in the section sec.
1318 * If we find two symbols with equal offset prefer one with a valid name.
1319 * The ELF format may have a better way to detect what type of symbol
1320 * it is, but this works for now.
1321 **/
1322static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1323 const char *sec)
1324{
1325 Elf_Sym *sym;
1326 Elf_Sym *near = NULL;
1327 Elf_Addr distance = ~0;
1328
1329 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1330 const char *symsec;
1331
1332 if (is_shndx_special(sym->st_shndx))
1333 continue;
1334 symsec = sec_name(elf, get_secindex(elf, sym));
1335 if (strcmp(symsec, sec) != 0)
1336 continue;
1337 if (!is_valid_name(elf, sym))
1338 continue;
1339 if (sym->st_value <= addr) {
1340 if ((addr - sym->st_value) < distance) {
1341 distance = addr - sym->st_value;
1342 near = sym;
1343 } else if ((addr - sym->st_value) == distance) {
1344 near = sym;
1345 }
1346 }
1347 }
1348 return near;
1349}
1350
1351/*
1352 * Convert a section name to the function/data attribute
1353 * .init.text => __init
1354 * .memexitconst => __memconst
1355 * etc.
1356 *
1357 * The memory of returned value has been allocated on a heap. The user of this
1358 * method should free it after usage.
1359*/
1360static char *sec2annotation(const char *s)
1361{
1362 if (match(s, init_exit_sections)) {
1363 char *p = NOFAIL(malloc(20));
1364 char *r = p;
1365
1366 *p++ = '_';
1367 *p++ = '_';
1368 if (*s == '.')
1369 s++;
1370 while (*s && *s != '.')
1371 *p++ = *s++;
1372 *p = '\0';
1373 if (*s == '.')
1374 s++;
1375 if (strstr(s, "rodata") != NULL)
1376 strcat(p, "const ");
1377 else if (strstr(s, "data") != NULL)
1378 strcat(p, "data ");
1379 else
1380 strcat(p, " ");
1381 return r;
1382 } else {
1383 return NOFAIL(strdup(""));
1384 }
1385}
1386
1387static int is_function(Elf_Sym *sym)
1388{
1389 if (sym)
1390 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1391 else
1392 return -1;
1393}
1394
1395static void print_section_list(const char * const list[20])
1396{
1397 const char *const *s = list;
1398
1399 while (*s) {
1400 fprintf(stderr, "%s", *s);
1401 s++;
1402 if (*s)
1403 fprintf(stderr, ", ");
1404 }
1405 fprintf(stderr, "\n");
1406}
1407
1408static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1409{
1410 switch (is_func) {
1411 case 0: *name = "variable"; *name_p = ""; break;
1412 case 1: *name = "function"; *name_p = "()"; break;
1413 default: *name = "(unknown reference)"; *name_p = ""; break;
1414 }
1415}
1416
1417/*
1418 * Print a warning about a section mismatch.
1419 * Try to find symbols near it so user can find it.
1420 * Check whitelist before warning - it may be a false positive.
1421 */
1422static void report_sec_mismatch(const char *modname,
1423 const struct sectioncheck *mismatch,
1424 const char *fromsec,
1425 unsigned long long fromaddr,
1426 const char *fromsym,
1427 int from_is_func,
1428 const char *tosec, const char *tosym,
1429 int to_is_func)
1430{
1431 const char *from, *from_p;
1432 const char *to, *to_p;
1433 char *prl_from;
1434 char *prl_to;
1435
1436 sec_mismatch_count++;
1437
1438 get_pretty_name(from_is_func, &from, &from_p);
1439 get_pretty_name(to_is_func, &to, &to_p);
1440
1441 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1442 "to the %s %s:%s%s\n",
1443 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1444 tosym, to_p);
1445
1446 switch (mismatch->mismatch) {
1447 case TEXT_TO_ANY_INIT:
1448 prl_from = sec2annotation(fromsec);
1449 prl_to = sec2annotation(tosec);
1450 fprintf(stderr,
1451 "The function %s%s() references\n"
1452 "the %s %s%s%s.\n"
1453 "This is often because %s lacks a %s\n"
1454 "annotation or the annotation of %s is wrong.\n",
1455 prl_from, fromsym,
1456 to, prl_to, tosym, to_p,
1457 fromsym, prl_to, tosym);
1458 free(prl_from);
1459 free(prl_to);
1460 break;
1461 case DATA_TO_ANY_INIT: {
1462 prl_to = sec2annotation(tosec);
1463 fprintf(stderr,
1464 "The variable %s references\n"
1465 "the %s %s%s%s\n"
1466 "If the reference is valid then annotate the\n"
1467 "variable with __init* or __refdata (see linux/init.h) "
1468 "or name the variable:\n",
1469 fromsym, to, prl_to, tosym, to_p);
1470 print_section_list(mismatch->symbol_white_list);
1471 free(prl_to);
1472 break;
1473 }
1474 case TEXT_TO_ANY_EXIT:
1475 prl_to = sec2annotation(tosec);
1476 fprintf(stderr,
1477 "The function %s() references a %s in an exit section.\n"
1478 "Often the %s %s%s has valid usage outside the exit section\n"
1479 "and the fix is to remove the %sannotation of %s.\n",
1480 fromsym, to, to, tosym, to_p, prl_to, tosym);
1481 free(prl_to);
1482 break;
1483 case DATA_TO_ANY_EXIT: {
1484 prl_to = sec2annotation(tosec);
1485 fprintf(stderr,
1486 "The variable %s references\n"
1487 "the %s %s%s%s\n"
1488 "If the reference is valid then annotate the\n"
1489 "variable with __exit* (see linux/init.h) or "
1490 "name the variable:\n",
1491 fromsym, to, prl_to, tosym, to_p);
1492 print_section_list(mismatch->symbol_white_list);
1493 free(prl_to);
1494 break;
1495 }
1496 case XXXINIT_TO_SOME_INIT:
1497 case XXXEXIT_TO_SOME_EXIT:
1498 prl_from = sec2annotation(fromsec);
1499 prl_to = sec2annotation(tosec);
1500 fprintf(stderr,
1501 "The %s %s%s%s references\n"
1502 "a %s %s%s%s.\n"
1503 "If %s is only used by %s then\n"
1504 "annotate %s with a matching annotation.\n",
1505 from, prl_from, fromsym, from_p,
1506 to, prl_to, tosym, to_p,
1507 tosym, fromsym, tosym);
1508 free(prl_from);
1509 free(prl_to);
1510 break;
1511 case ANY_INIT_TO_ANY_EXIT:
1512 prl_from = sec2annotation(fromsec);
1513 prl_to = sec2annotation(tosec);
1514 fprintf(stderr,
1515 "The %s %s%s%s references\n"
1516 "a %s %s%s%s.\n"
1517 "This is often seen when error handling "
1518 "in the init function\n"
1519 "uses functionality in the exit path.\n"
1520 "The fix is often to remove the %sannotation of\n"
1521 "%s%s so it may be used outside an exit section.\n",
1522 from, prl_from, fromsym, from_p,
1523 to, prl_to, tosym, to_p,
1524 prl_to, tosym, to_p);
1525 free(prl_from);
1526 free(prl_to);
1527 break;
1528 case ANY_EXIT_TO_ANY_INIT:
1529 prl_from = sec2annotation(fromsec);
1530 prl_to = sec2annotation(tosec);
1531 fprintf(stderr,
1532 "The %s %s%s%s references\n"
1533 "a %s %s%s%s.\n"
1534 "This is often seen when error handling "
1535 "in the exit function\n"
1536 "uses functionality in the init path.\n"
1537 "The fix is often to remove the %sannotation of\n"
1538 "%s%s so it may be used outside an init section.\n",
1539 from, prl_from, fromsym, from_p,
1540 to, prl_to, tosym, to_p,
1541 prl_to, tosym, to_p);
1542 free(prl_from);
1543 free(prl_to);
1544 break;
1545 case EXPORT_TO_INIT_EXIT:
1546 prl_to = sec2annotation(tosec);
1547 fprintf(stderr,
1548 "The symbol %s is exported and annotated %s\n"
1549 "Fix this by removing the %sannotation of %s "
1550 "or drop the export.\n",
1551 tosym, prl_to, prl_to, tosym);
1552 free(prl_to);
1553 break;
1554 case EXTABLE_TO_NON_TEXT:
1555 fatal("There's a special handler for this mismatch type, "
1556 "we should never get here.");
1557 break;
1558 }
1559 fprintf(stderr, "\n");
1560}
1561
1562static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1563 const struct sectioncheck* const mismatch,
1564 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1565{
1566 const char *tosec;
1567 Elf_Sym *to;
1568 Elf_Sym *from;
1569 const char *tosym;
1570 const char *fromsym;
1571
1572 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1573 fromsym = sym_name(elf, from);
1574
1575 if (strstarts(fromsym, "reference___initcall"))
1576 return;
1577
1578 tosec = sec_name(elf, get_secindex(elf, sym));
1579 to = find_elf_symbol(elf, r->r_addend, sym);
1580 tosym = sym_name(elf, to);
1581
1582 /* check whitelist - we may ignore it */
1583 if (secref_whitelist(mismatch,
1584 fromsec, fromsym, tosec, tosym)) {
1585 report_sec_mismatch(modname, mismatch,
1586 fromsec, r->r_offset, fromsym,
1587 is_function(from), tosec, tosym,
1588 is_function(to));
1589 }
1590}
1591
1592static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1593{
1594 if (section_index > elf->num_sections)
1595 fatal("section_index is outside elf->num_sections!\n");
1596
1597 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1598}
1599
1600/*
1601 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1602 * to know the sizeof(struct exception_table_entry) for the target architecture.
1603 */
1604static unsigned int extable_entry_size = 0;
1605static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1606{
1607 /*
1608 * If we're currently checking the second relocation within __ex_table,
1609 * that relocation offset tells us the offsetof(struct
1610 * exception_table_entry, fixup) which is equal to sizeof(struct
1611 * exception_table_entry) divided by two. We use that to our advantage
1612 * since there's no portable way to get that size as every architecture
1613 * seems to go with different sized types. Not pretty but better than
1614 * hard-coding the size for every architecture..
1615 */
1616 if (!extable_entry_size)
1617 extable_entry_size = r->r_offset * 2;
1618}
1619
1620static inline bool is_extable_fault_address(Elf_Rela *r)
1621{
1622 /*
1623 * extable_entry_size is only discovered after we've handled the
1624 * _second_ relocation in __ex_table, so only abort when we're not
1625 * handling the first reloc and extable_entry_size is zero.
1626 */
1627 if (r->r_offset && extable_entry_size == 0)
1628 fatal("extable_entry size hasn't been discovered!\n");
1629
1630 return ((r->r_offset == 0) ||
1631 (r->r_offset % extable_entry_size == 0));
1632}
1633
1634#define is_second_extable_reloc(Start, Cur, Sec) \
1635 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1636
1637static void report_extable_warnings(const char* modname, struct elf_info* elf,
1638 const struct sectioncheck* const mismatch,
1639 Elf_Rela* r, Elf_Sym* sym,
1640 const char* fromsec, const char* tosec)
1641{
1642 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1643 const char* fromsym_name = sym_name(elf, fromsym);
1644 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1645 const char* tosym_name = sym_name(elf, tosym);
1646 const char* from_pretty_name;
1647 const char* from_pretty_name_p;
1648 const char* to_pretty_name;
1649 const char* to_pretty_name_p;
1650
1651 get_pretty_name(is_function(fromsym),
1652 &from_pretty_name, &from_pretty_name_p);
1653 get_pretty_name(is_function(tosym),
1654 &to_pretty_name, &to_pretty_name_p);
1655
1656 warn("%s(%s+0x%lx): Section mismatch in reference"
1657 " from the %s %s%s to the %s %s:%s%s\n",
1658 modname, fromsec, (long)r->r_offset, from_pretty_name,
1659 fromsym_name, from_pretty_name_p,
1660 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1661
1662 if (!match(tosec, mismatch->bad_tosec) &&
1663 is_executable_section(elf, get_secindex(elf, sym)))
1664 fprintf(stderr,
1665 "The relocation at %s+0x%lx references\n"
1666 "section \"%s\" which is not in the list of\n"
1667 "authorized sections. If you're adding a new section\n"
1668 "and/or if this reference is valid, add \"%s\" to the\n"
1669 "list of authorized sections to jump to on fault.\n"
1670 "This can be achieved by adding \"%s\" to \n"
1671 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1672 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1673}
1674
1675static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1676 const struct sectioncheck* const mismatch,
1677 Elf_Rela* r, Elf_Sym* sym,
1678 const char *fromsec)
1679{
1680 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1681
1682 sec_mismatch_count++;
1683
1684 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
1685
1686 if (match(tosec, mismatch->bad_tosec))
1687 fatal("The relocation at %s+0x%lx references\n"
1688 "section \"%s\" which is black-listed.\n"
1689 "Something is seriously wrong and should be fixed.\n"
1690 "You might get more information about where this is\n"
1691 "coming from by using scripts/check_extable.sh %s\n",
1692 fromsec, (long)r->r_offset, tosec, modname);
1693 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1694 if (is_extable_fault_address(r))
1695 fatal("The relocation at %s+0x%lx references\n"
1696 "section \"%s\" which is not executable, IOW\n"
1697 "it is not possible for the kernel to fault\n"
1698 "at that address. Something is seriously wrong\n"
1699 "and should be fixed.\n",
1700 fromsec, (long)r->r_offset, tosec);
1701 else
1702 fatal("The relocation at %s+0x%lx references\n"
1703 "section \"%s\" which is not executable, IOW\n"
1704 "the kernel will fault if it ever tries to\n"
1705 "jump to it. Something is seriously wrong\n"
1706 "and should be fixed.\n",
1707 fromsec, (long)r->r_offset, tosec);
1708 }
1709}
1710
1711static void check_section_mismatch(const char *modname, struct elf_info *elf,
1712 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1713{
1714 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1715 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1716
1717 if (mismatch) {
1718 if (mismatch->handler)
1719 mismatch->handler(modname, elf, mismatch,
1720 r, sym, fromsec);
1721 else
1722 default_mismatch_handler(modname, elf, mismatch,
1723 r, sym, fromsec);
1724 }
1725}
1726
1727static unsigned int *reloc_location(struct elf_info *elf,
1728 Elf_Shdr *sechdr, Elf_Rela *r)
1729{
1730 return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset);
1731}
1732
1733static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1734{
1735 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1736 unsigned int *location = reloc_location(elf, sechdr, r);
1737
1738 switch (r_typ) {
1739 case R_386_32:
1740 r->r_addend = TO_NATIVE(*location);
1741 break;
1742 case R_386_PC32:
1743 r->r_addend = TO_NATIVE(*location) + 4;
1744 /* For CONFIG_RELOCATABLE=y */
1745 if (elf->hdr->e_type == ET_EXEC)
1746 r->r_addend += r->r_offset;
1747 break;
1748 }
1749 return 0;
1750}
1751
1752#ifndef R_ARM_CALL
1753#define R_ARM_CALL 28
1754#endif
1755#ifndef R_ARM_JUMP24
1756#define R_ARM_JUMP24 29
1757#endif
1758
1759#ifndef R_ARM_THM_CALL
1760#define R_ARM_THM_CALL 10
1761#endif
1762#ifndef R_ARM_THM_JUMP24
1763#define R_ARM_THM_JUMP24 30
1764#endif
1765#ifndef R_ARM_THM_JUMP19
1766#define R_ARM_THM_JUMP19 51
1767#endif
1768
1769static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1770{
1771 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1772
1773 switch (r_typ) {
1774 case R_ARM_ABS32:
1775 /* From ARM ABI: (S + A) | T */
1776 r->r_addend = (int)(long)
1777 (elf->symtab_start + ELF_R_SYM(r->r_info));
1778 break;
1779 case R_ARM_PC24:
1780 case R_ARM_CALL:
1781 case R_ARM_JUMP24:
1782 case R_ARM_THM_CALL:
1783 case R_ARM_THM_JUMP24:
1784 case R_ARM_THM_JUMP19:
1785 /* From ARM ABI: ((S + A) | T) - P */
1786 r->r_addend = (int)(long)(elf->hdr +
1787 sechdr->sh_offset +
1788 (r->r_offset - sechdr->sh_addr));
1789 break;
1790 default:
1791 return 1;
1792 }
1793 return 0;
1794}
1795
1796static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1797{
1798 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1799 unsigned int *location = reloc_location(elf, sechdr, r);
1800 unsigned int inst;
1801
1802 if (r_typ == R_MIPS_HI16)
1803 return 1; /* skip this */
1804 inst = TO_NATIVE(*location);
1805 switch (r_typ) {
1806 case R_MIPS_LO16:
1807 r->r_addend = inst & 0xffff;
1808 break;
1809 case R_MIPS_26:
1810 r->r_addend = (inst & 0x03ffffff) << 2;
1811 break;
1812 case R_MIPS_32:
1813 r->r_addend = inst;
1814 break;
1815 }
1816 return 0;
1817}
1818
1819static void section_rela(const char *modname, struct elf_info *elf,
1820 Elf_Shdr *sechdr)
1821{
1822 Elf_Sym *sym;
1823 Elf_Rela *rela;
1824 Elf_Rela r;
1825 unsigned int r_sym;
1826 const char *fromsec;
1827
1828 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1829 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1830
1831 fromsec = sech_name(elf, sechdr);
1832 fromsec += strlen(".rela");
1833 /* if from section (name) is know good then skip it */
1834 if (match(fromsec, section_white_list))
1835 return;
1836
1837 for (rela = start; rela < stop; rela++) {
1838 r.r_offset = TO_NATIVE(rela->r_offset);
1839#if KERNEL_ELFCLASS == ELFCLASS64
1840 if (elf->hdr->e_machine == EM_MIPS) {
1841 unsigned int r_typ;
1842 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1843 r_sym = TO_NATIVE(r_sym);
1844 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1845 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1846 } else {
1847 r.r_info = TO_NATIVE(rela->r_info);
1848 r_sym = ELF_R_SYM(r.r_info);
1849 }
1850#else
1851 r.r_info = TO_NATIVE(rela->r_info);
1852 r_sym = ELF_R_SYM(r.r_info);
1853#endif
1854 r.r_addend = TO_NATIVE(rela->r_addend);
1855 sym = elf->symtab_start + r_sym;
1856 /* Skip special sections */
1857 if (is_shndx_special(sym->st_shndx))
1858 continue;
1859 if (is_second_extable_reloc(start, rela, fromsec))
1860 find_extable_entry_size(fromsec, &r);
1861 check_section_mismatch(modname, elf, &r, sym, fromsec);
1862 }
1863}
1864
1865static void section_rel(const char *modname, struct elf_info *elf,
1866 Elf_Shdr *sechdr)
1867{
1868 Elf_Sym *sym;
1869 Elf_Rel *rel;
1870 Elf_Rela r;
1871 unsigned int r_sym;
1872 const char *fromsec;
1873
1874 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1875 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1876
1877 fromsec = sech_name(elf, sechdr);
1878 fromsec += strlen(".rel");
1879 /* if from section (name) is know good then skip it */
1880 if (match(fromsec, section_white_list))
1881 return;
1882
1883 for (rel = start; rel < stop; rel++) {
1884 r.r_offset = TO_NATIVE(rel->r_offset);
1885#if KERNEL_ELFCLASS == ELFCLASS64
1886 if (elf->hdr->e_machine == EM_MIPS) {
1887 unsigned int r_typ;
1888 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1889 r_sym = TO_NATIVE(r_sym);
1890 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1891 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1892 } else {
1893 r.r_info = TO_NATIVE(rel->r_info);
1894 r_sym = ELF_R_SYM(r.r_info);
1895 }
1896#else
1897 r.r_info = TO_NATIVE(rel->r_info);
1898 r_sym = ELF_R_SYM(r.r_info);
1899#endif
1900 r.r_addend = 0;
1901 switch (elf->hdr->e_machine) {
1902 case EM_386:
1903 if (addend_386_rel(elf, sechdr, &r))
1904 continue;
1905 break;
1906 case EM_ARM:
1907 if (addend_arm_rel(elf, sechdr, &r))
1908 continue;
1909 break;
1910 case EM_MIPS:
1911 if (addend_mips_rel(elf, sechdr, &r))
1912 continue;
1913 break;
1914 }
1915 sym = elf->symtab_start + r_sym;
1916 /* Skip special sections */
1917 if (is_shndx_special(sym->st_shndx))
1918 continue;
1919 if (is_second_extable_reloc(start, rel, fromsec))
1920 find_extable_entry_size(fromsec, &r);
1921 check_section_mismatch(modname, elf, &r, sym, fromsec);
1922 }
1923}
1924
1925/**
1926 * A module includes a number of sections that are discarded
1927 * either when loaded or when used as built-in.
1928 * For loaded modules all functions marked __init and all data
1929 * marked __initdata will be discarded when the module has been initialized.
1930 * Likewise for modules used built-in the sections marked __exit
1931 * are discarded because __exit marked function are supposed to be called
1932 * only when a module is unloaded which never happens for built-in modules.
1933 * The check_sec_ref() function traverses all relocation records
1934 * to find all references to a section that reference a section that will
1935 * be discarded and warns about it.
1936 **/
1937static void check_sec_ref(struct module *mod, const char *modname,
1938 struct elf_info *elf)
1939{
1940 int i;
1941 Elf_Shdr *sechdrs = elf->sechdrs;
1942
1943 /* Walk through all sections */
1944 for (i = 0; i < elf->num_sections; i++) {
1945 check_section(modname, elf, &elf->sechdrs[i]);
1946 /* We want to process only relocation sections and not .init */
1947 if (sechdrs[i].sh_type == SHT_RELA)
1948 section_rela(modname, elf, &elf->sechdrs[i]);
1949 else if (sechdrs[i].sh_type == SHT_REL)
1950 section_rel(modname, elf, &elf->sechdrs[i]);
1951 }
1952}
1953
1954static char *remove_dot(char *s)
1955{
1956 size_t n = strcspn(s, ".");
1957
1958 if (n && s[n]) {
1959 size_t m = strspn(s + n + 1, "0123456789");
1960 if (m && (s[n + m] == '.' || s[n + m] == 0))
1961 s[n] = 0;
1962
1963 /* strip trailing .lto */
1964 if (strends(s, ".lto"))
1965 s[strlen(s) - 4] = '\0';
1966 }
1967 return s;
1968}
1969
1970static void read_symbols(const char *modname)
1971{
1972 const char *symname;
1973 char *version;
1974 char *license;
1975 char *namespace;
1976 struct module *mod;
1977 struct elf_info info = { };
1978 Elf_Sym *sym;
1979
1980 if (!parse_elf(&info, modname))
1981 return;
1982
1983 {
1984 char *tmp;
1985
1986 /* strip trailing .o */
1987 tmp = NOFAIL(strdup(modname));
1988 tmp[strlen(tmp) - 2] = '\0';
1989 /* strip trailing .lto */
1990 if (strends(tmp, ".lto"))
1991 tmp[strlen(tmp) - 4] = '\0';
1992 mod = new_module(tmp);
1993 free(tmp);
1994 }
1995
1996 if (!mod->is_vmlinux) {
1997 license = get_modinfo(&info, "license");
1998 if (!license)
1999 error("missing MODULE_LICENSE() in %s\n", modname);
2000 while (license) {
2001 if (license_is_gpl_compatible(license))
2002 mod->gpl_compatible = 1;
2003 else {
2004 mod->gpl_compatible = 0;
2005 break;
2006 }
2007 license = get_next_modinfo(&info, "license", license);
2008 }
2009
2010 namespace = get_modinfo(&info, "import_ns");
2011 while (namespace) {
2012 add_namespace(&mod->imported_namespaces, namespace);
2013 namespace = get_next_modinfo(&info, "import_ns",
2014 namespace);
2015 }
2016 }
2017
2018 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2019 symname = remove_dot(info.strtab + sym->st_name);
2020
2021 handle_symbol(mod, &info, sym, symname);
2022 handle_moddevtable(mod, &info, sym, symname);
2023 }
2024
2025 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2026 symname = remove_dot(info.strtab + sym->st_name);
2027
2028 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
2029 if (strstarts(symname, "__kstrtabns_"))
2030 sym_update_namespace(symname + strlen("__kstrtabns_"),
2031 namespace_from_kstrtabns(&info,
2032 sym));
2033
2034 if (strstarts(symname, "__crc_"))
2035 handle_modversion(mod, &info, sym,
2036 symname + strlen("__crc_"));
2037 }
2038
2039 // check for static EXPORT_SYMBOL_* functions && global vars
2040 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2041 unsigned char bind = ELF_ST_BIND(sym->st_info);
2042
2043 if (bind == STB_GLOBAL || bind == STB_WEAK) {
2044 struct symbol *s =
2045 find_symbol(remove_dot(info.strtab +
2046 sym->st_name));
2047
2048 if (s)
2049 s->is_static = 0;
2050 }
2051 }
2052
2053 check_sec_ref(mod, modname, &info);
2054
2055 if (!mod->is_vmlinux) {
2056 version = get_modinfo(&info, "version");
2057 if (version || all_versions)
2058 get_src_version(modname, mod->srcversion,
2059 sizeof(mod->srcversion) - 1);
2060 }
2061
2062 parse_elf_finish(&info);
2063
2064 /* Our trick to get versioning for module struct etc. - it's
2065 * never passed as an argument to an exported function, so
2066 * the automatic versioning doesn't pick it up, but it's really
2067 * important anyhow */
2068 if (modversions)
2069 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2070}
2071
2072static void read_symbols_from_files(const char *filename)
2073{
2074 FILE *in = stdin;
2075 char fname[PATH_MAX];
2076
2077 if (strcmp(filename, "-") != 0) {
2078 in = fopen(filename, "r");
2079 if (!in)
2080 fatal("Can't open filenames file %s: %m", filename);
2081 }
2082
2083 while (fgets(fname, PATH_MAX, in) != NULL) {
2084 if (strends(fname, "\n"))
2085 fname[strlen(fname)-1] = '\0';
2086 read_symbols(fname);
2087 }
2088
2089 if (in != stdin)
2090 fclose(in);
2091}
2092
2093#define SZ 500
2094
2095/* We first write the generated file into memory using the
2096 * following helper, then compare to the file on disk and
2097 * only update the later if anything changed */
2098
2099void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2100 const char *fmt, ...)
2101{
2102 char tmp[SZ];
2103 int len;
2104 va_list ap;
2105
2106 va_start(ap, fmt);
2107 len = vsnprintf(tmp, SZ, fmt, ap);
2108 buf_write(buf, tmp, len);
2109 va_end(ap);
2110}
2111
2112void buf_write(struct buffer *buf, const char *s, int len)
2113{
2114 if (buf->size - buf->pos < len) {
2115 buf->size += len + SZ;
2116 buf->p = NOFAIL(realloc(buf->p, buf->size));
2117 }
2118 strncpy(buf->p + buf->pos, s, len);
2119 buf->pos += len;
2120}
2121
2122static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2123{
2124 switch (exp) {
2125 case export_gpl:
2126 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
2127 m, s);
2128 break;
2129 case export_plain:
2130 case export_unknown:
2131 /* ignore */
2132 break;
2133 }
2134}
2135
2136static void check_exports(struct module *mod)
2137{
2138 struct symbol *s, *exp;
2139
2140 for (s = mod->unres; s; s = s->next) {
2141 const char *basename;
2142 exp = find_symbol(s->name);
2143 if (!exp || exp->module == mod) {
2144 if (have_vmlinux && !s->weak)
2145 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
2146 "\"%s\" [%s.ko] undefined!\n",
2147 s->name, mod->name);
2148 continue;
2149 }
2150 basename = strrchr(mod->name, '/');
2151 if (basename)
2152 basename++;
2153 else
2154 basename = mod->name;
2155
2156 if (exp->namespace &&
2157 !module_imports_namespace(mod, exp->namespace)) {
2158 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
2159 "module %s uses symbol %s from namespace %s, but does not import it.\n",
2160 basename, exp->name, exp->namespace);
2161 add_namespace(&mod->missing_namespaces, exp->namespace);
2162 }
2163
2164 if (!mod->gpl_compatible)
2165 check_for_gpl_usage(exp->export, basename, exp->name);
2166 }
2167}
2168
2169static void check_modname_len(struct module *mod)
2170{
2171 const char *mod_name;
2172
2173 mod_name = strrchr(mod->name, '/');
2174 if (mod_name == NULL)
2175 mod_name = mod->name;
2176 else
2177 mod_name++;
2178 if (strlen(mod_name) >= MODULE_NAME_LEN)
2179 error("module name is too long [%s.ko]\n", mod->name);
2180}
2181
2182/**
2183 * Header for the generated file
2184 **/
2185static void add_header(struct buffer *b, struct module *mod)
2186{
2187 buf_printf(b, "#include <linux/module.h>\n");
2188 /*
2189 * Include build-salt.h after module.h in order to
2190 * inherit the definitions.
2191 */
2192 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
2193 buf_printf(b, "#include <linux/build-salt.h>\n");
2194 buf_printf(b, "#include <linux/vermagic.h>\n");
2195 buf_printf(b, "#include <linux/compiler.h>\n");
2196 buf_printf(b, "\n");
2197 buf_printf(b, "BUILD_SALT;\n");
2198 buf_printf(b, "\n");
2199 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2200 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2201 buf_printf(b, "\n");
2202 buf_printf(b, "__visible struct module __this_module\n");
2203 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
2204 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2205 if (mod->has_init)
2206 buf_printf(b, "\t.init = init_module,\n");
2207 if (mod->has_cleanup)
2208 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2209 "\t.exit = cleanup_module,\n"
2210 "#endif\n");
2211 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2212 buf_printf(b, "};\n");
2213}
2214
2215static void add_intree_flag(struct buffer *b, int is_intree)
2216{
2217 if (is_intree)
2218 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2219}
2220
2221/* Cannot check for assembler */
2222static void add_retpoline(struct buffer *b)
2223{
2224 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2225 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2226 buf_printf(b, "#endif\n");
2227}
2228
2229static void add_staging_flag(struct buffer *b, const char *name)
2230{
2231 if (strstarts(name, "drivers/staging"))
2232 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2233}
2234
2235/**
2236 * Record CRCs for unresolved symbols
2237 **/
2238static void add_versions(struct buffer *b, struct module *mod)
2239{
2240 struct symbol *s, *exp;
2241
2242 for (s = mod->unres; s; s = s->next) {
2243 exp = find_symbol(s->name);
2244 if (!exp || exp->module == mod)
2245 continue;
2246 s->module = exp->module;
2247 s->crc_valid = exp->crc_valid;
2248 s->crc = exp->crc;
2249 }
2250
2251 if (!modversions)
2252 return;
2253
2254 buf_printf(b, "\n");
2255 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2256 buf_printf(b, "__used __section(\"__versions\") = {\n");
2257
2258 for (s = mod->unres; s; s = s->next) {
2259 if (!s->module)
2260 continue;
2261 if (!s->crc_valid) {
2262 warn("\"%s\" [%s.ko] has no CRC!\n",
2263 s->name, mod->name);
2264 continue;
2265 }
2266 if (strlen(s->name) >= MODULE_NAME_LEN) {
2267 error("too long symbol \"%s\" [%s.ko]\n",
2268 s->name, mod->name);
2269 break;
2270 }
2271 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2272 s->crc, s->name);
2273 }
2274
2275 buf_printf(b, "};\n");
2276}
2277
2278static void add_depends(struct buffer *b, struct module *mod)
2279{
2280 struct symbol *s;
2281 int first = 1;
2282
2283 /* Clear ->seen flag of modules that own symbols needed by this. */
2284 for (s = mod->unres; s; s = s->next)
2285 if (s->module)
2286 s->module->seen = s->module->is_vmlinux;
2287
2288 buf_printf(b, "\n");
2289 buf_printf(b, "MODULE_INFO(depends, \"");
2290 for (s = mod->unres; s; s = s->next) {
2291 const char *p;
2292 if (!s->module)
2293 continue;
2294
2295 if (s->module->seen)
2296 continue;
2297
2298 s->module->seen = 1;
2299 p = strrchr(s->module->name, '/');
2300 if (p)
2301 p++;
2302 else
2303 p = s->module->name;
2304 buf_printf(b, "%s%s", first ? "" : ",", p);
2305 first = 0;
2306 }
2307 buf_printf(b, "\");\n");
2308}
2309
2310static void add_srcversion(struct buffer *b, struct module *mod)
2311{
2312 if (mod->srcversion[0]) {
2313 buf_printf(b, "\n");
2314 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2315 mod->srcversion);
2316 }
2317}
2318
2319static void write_buf(struct buffer *b, const char *fname)
2320{
2321 FILE *file;
2322
2323 file = fopen(fname, "w");
2324 if (!file) {
2325 perror(fname);
2326 exit(1);
2327 }
2328 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2329 perror(fname);
2330 exit(1);
2331 }
2332 if (fclose(file) != 0) {
2333 perror(fname);
2334 exit(1);
2335 }
2336}
2337
2338static void write_if_changed(struct buffer *b, const char *fname)
2339{
2340 char *tmp;
2341 FILE *file;
2342 struct stat st;
2343
2344 file = fopen(fname, "r");
2345 if (!file)
2346 goto write;
2347
2348 if (fstat(fileno(file), &st) < 0)
2349 goto close_write;
2350
2351 if (st.st_size != b->pos)
2352 goto close_write;
2353
2354 tmp = NOFAIL(malloc(b->pos));
2355 if (fread(tmp, 1, b->pos, file) != b->pos)
2356 goto free_write;
2357
2358 if (memcmp(tmp, b->p, b->pos) != 0)
2359 goto free_write;
2360
2361 free(tmp);
2362 fclose(file);
2363 return;
2364
2365 free_write:
2366 free(tmp);
2367 close_write:
2368 fclose(file);
2369 write:
2370 write_buf(b, fname);
2371}
2372
2373/* parse Module.symvers file. line format:
2374 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2375 **/
2376static void read_dump(const char *fname)
2377{
2378 char *buf, *pos, *line;
2379
2380 buf = read_text_file(fname);
2381 if (!buf)
2382 /* No symbol versions, silently ignore */
2383 return;
2384
2385 pos = buf;
2386
2387 while ((line = get_line(&pos))) {
2388 char *symname, *namespace, *modname, *d, *export;
2389 unsigned int crc;
2390 struct module *mod;
2391 struct symbol *s;
2392
2393 if (!(symname = strchr(line, '\t')))
2394 goto fail;
2395 *symname++ = '\0';
2396 if (!(modname = strchr(symname, '\t')))
2397 goto fail;
2398 *modname++ = '\0';
2399 if (!(export = strchr(modname, '\t')))
2400 goto fail;
2401 *export++ = '\0';
2402 if (!(namespace = strchr(export, '\t')))
2403 goto fail;
2404 *namespace++ = '\0';
2405
2406 crc = strtoul(line, &d, 16);
2407 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2408 goto fail;
2409 mod = find_module(modname);
2410 if (!mod) {
2411 mod = new_module(modname);
2412 mod->from_dump = 1;
2413 }
2414 s = sym_add_exported(symname, mod, export_no(export));
2415 s->is_static = 0;
2416 sym_set_crc(symname, crc);
2417 sym_update_namespace(symname, namespace);
2418 }
2419 free(buf);
2420 return;
2421fail:
2422 free(buf);
2423 fatal("parse error in symbol dump file\n");
2424}
2425
2426/* For normal builds always dump all symbols.
2427 * For external modules only dump symbols
2428 * that are not read from kernel Module.symvers.
2429 **/
2430static int dump_sym(struct symbol *sym)
2431{
2432 if (!external_module)
2433 return 1;
2434 if (sym->module->from_dump)
2435 return 0;
2436 return 1;
2437}
2438
2439static void write_dump(const char *fname)
2440{
2441 struct buffer buf = { };
2442 struct symbol *symbol;
2443 const char *namespace;
2444 int n;
2445
2446 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2447 symbol = symbolhash[n];
2448 while (symbol) {
2449 if (dump_sym(symbol)) {
2450 namespace = symbol->namespace;
2451 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
2452 symbol->crc, symbol->name,
2453 symbol->module->name,
2454 export_str(symbol->export),
2455 namespace ? namespace : "");
2456 }
2457 symbol = symbol->next;
2458 }
2459 }
2460 write_buf(&buf, fname);
2461 free(buf.p);
2462}
2463
2464static void write_namespace_deps_files(const char *fname)
2465{
2466 struct module *mod;
2467 struct namespace_list *ns;
2468 struct buffer ns_deps_buf = {};
2469
2470 for (mod = modules; mod; mod = mod->next) {
2471
2472 if (mod->from_dump || !mod->missing_namespaces)
2473 continue;
2474
2475 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2476
2477 for (ns = mod->missing_namespaces; ns; ns = ns->next)
2478 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2479
2480 buf_printf(&ns_deps_buf, "\n");
2481 }
2482
2483 write_if_changed(&ns_deps_buf, fname);
2484 free(ns_deps_buf.p);
2485}
2486
2487struct dump_list {
2488 struct dump_list *next;
2489 const char *file;
2490};
2491
2492int main(int argc, char **argv)
2493{
2494 struct module *mod;
2495 struct buffer buf = { };
2496 char *missing_namespace_deps = NULL;
2497 char *dump_write = NULL, *files_source = NULL;
2498 int opt;
2499 int n;
2500 struct dump_list *dump_read_start = NULL;
2501 struct dump_list **dump_read_iter = &dump_read_start;
2502
2503 while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) {
2504 switch (opt) {
2505 case 'e':
2506 external_module = 1;
2507 break;
2508 case 'i':
2509 *dump_read_iter =
2510 NOFAIL(calloc(1, sizeof(**dump_read_iter)));
2511 (*dump_read_iter)->file = optarg;
2512 dump_read_iter = &(*dump_read_iter)->next;
2513 break;
2514 case 'm':
2515 modversions = 1;
2516 break;
2517 case 'n':
2518 ignore_missing_files = 1;
2519 break;
2520 case 'o':
2521 dump_write = optarg;
2522 break;
2523 case 'a':
2524 all_versions = 1;
2525 break;
2526 case 'T':
2527 files_source = optarg;
2528 break;
2529 case 'w':
2530 warn_unresolved = 1;
2531 break;
2532 case 'E':
2533 sec_mismatch_warn_only = false;
2534 break;
2535 case 'N':
2536 allow_missing_ns_imports = 1;
2537 break;
2538 case 'd':
2539 missing_namespace_deps = optarg;
2540 break;
2541 default:
2542 exit(1);
2543 }
2544 }
2545
2546 while (dump_read_start) {
2547 struct dump_list *tmp;
2548
2549 read_dump(dump_read_start->file);
2550 tmp = dump_read_start->next;
2551 free(dump_read_start);
2552 dump_read_start = tmp;
2553 }
2554
2555 while (optind < argc)
2556 read_symbols(argv[optind++]);
2557
2558 if (files_source)
2559 read_symbols_from_files(files_source);
2560
2561 /*
2562 * When there's no vmlinux, don't print warnings about
2563 * unresolved symbols (since there'll be too many ;)
2564 */
2565 if (!have_vmlinux)
2566 warn("Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped.\n");
2567
2568 for (mod = modules; mod; mod = mod->next) {
2569 char fname[PATH_MAX];
2570
2571 if (mod->is_vmlinux || mod->from_dump)
2572 continue;
2573
2574 buf.pos = 0;
2575
2576 check_modname_len(mod);
2577 check_exports(mod);
2578
2579 add_header(&buf, mod);
2580 add_intree_flag(&buf, !external_module);
2581 add_retpoline(&buf);
2582 add_staging_flag(&buf, mod->name);
2583 add_versions(&buf, mod);
2584 add_depends(&buf, mod);
2585 add_moddevtable(&buf, mod);
2586 add_srcversion(&buf, mod);
2587
2588 sprintf(fname, "%s.mod.c", mod->name);
2589 write_if_changed(&buf, fname);
2590 }
2591
2592 if (missing_namespace_deps)
2593 write_namespace_deps_files(missing_namespace_deps);
2594
2595 if (dump_write)
2596 write_dump(dump_write);
2597 if (sec_mismatch_count && !sec_mismatch_warn_only)
2598 error("Section mismatches detected.\n"
2599 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2600 for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
2601 struct symbol *s;
2602
2603 for (s = symbolhash[n]; s; s = s->next) {
2604 if (s->is_static)
2605 error("\"%s\" [%s] is a static %s\n",
2606 s->name, s->module->name,
2607 export_str(s->export));
2608 }
2609 }
2610
2611 free(buf.p);
2612
2613 return error_occurred ? 1 : 0;
2614}