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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/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
27static int all_versions = 0;
28/* If we are modposting external module set to 1 */
29static int external_module = 0;
30/* Only warn about unresolved symbols */
31static int warn_unresolved = 0;
32/* How a symbol is exported */
33static int sec_mismatch_count = 0;
34static int sec_mismatch_warn_only = true;
35/* ignore missing files */
36static int ignore_missing_files;
37/* If set to 1, only warn (instead of error) about missing ns imports */
38static int allow_missing_ns_imports;
39
40static bool error_occurred;
41
42/*
43 * Cut off the warnings when there are too many. This typically occurs when
44 * vmlinux is missing. ('make modules' without building vmlinux.)
45 */
46#define MAX_UNRESOLVED_REPORTS 10
47static unsigned int nr_unresolved;
48
49enum export {
50 export_plain,
51 export_gpl,
52 export_unknown
53};
54
55/* In kernel, this size is defined in linux/module.h;
56 * here we use Elf_Addr instead of long for covering cross-compile
57 */
58
59#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
60
61void __attribute__((format(printf, 2, 3)))
62modpost_log(enum loglevel loglevel, const char *fmt, ...)
63{
64 va_list arglist;
65
66 switch (loglevel) {
67 case LOG_WARN:
68 fprintf(stderr, "WARNING: ");
69 break;
70 case LOG_ERROR:
71 fprintf(stderr, "ERROR: ");
72 break;
73 case LOG_FATAL:
74 fprintf(stderr, "FATAL: ");
75 break;
76 default: /* invalid loglevel, ignore */
77 break;
78 }
79
80 fprintf(stderr, "modpost: ");
81
82 va_start(arglist, fmt);
83 vfprintf(stderr, fmt, arglist);
84 va_end(arglist);
85
86 if (loglevel == LOG_FATAL)
87 exit(1);
88 if (loglevel == LOG_ERROR)
89 error_occurred = true;
90}
91
92void *do_nofail(void *ptr, const char *expr)
93{
94 if (!ptr)
95 fatal("Memory allocation failure: %s.\n", expr);
96
97 return ptr;
98}
99
100char *read_text_file(const char *filename)
101{
102 struct stat st;
103 size_t nbytes;
104 int fd;
105 char *buf;
106
107 fd = open(filename, O_RDONLY);
108 if (fd < 0) {
109 perror(filename);
110 exit(1);
111 }
112
113 if (fstat(fd, &st) < 0) {
114 perror(filename);
115 exit(1);
116 }
117
118 buf = NOFAIL(malloc(st.st_size + 1));
119
120 nbytes = st.st_size;
121
122 while (nbytes) {
123 ssize_t bytes_read;
124
125 bytes_read = read(fd, buf, nbytes);
126 if (bytes_read < 0) {
127 perror(filename);
128 exit(1);
129 }
130
131 nbytes -= bytes_read;
132 }
133 buf[st.st_size] = '\0';
134
135 close(fd);
136
137 return buf;
138}
139
140char *get_line(char **stringp)
141{
142 char *orig = *stringp, *next;
143
144 /* do not return the unwanted extra line at EOF */
145 if (!orig || *orig == '\0')
146 return NULL;
147
148 /* don't use strsep here, it is not available everywhere */
149 next = strchr(orig, '\n');
150 if (next)
151 *next++ = '\0';
152
153 *stringp = next;
154
155 return orig;
156}
157
158/* A list of all modules we processed */
159static struct module *modules;
160
161static struct module *find_module(const char *modname)
162{
163 struct module *mod;
164
165 for (mod = modules; mod; mod = mod->next)
166 if (strcmp(mod->name, modname) == 0)
167 break;
168 return mod;
169}
170
171static struct module *new_module(const char *modname)
172{
173 struct module *mod;
174
175 mod = NOFAIL(malloc(sizeof(*mod) + strlen(modname) + 1));
176 memset(mod, 0, sizeof(*mod));
177
178 /* add to list */
179 strcpy(mod->name, modname);
180 mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0);
181 mod->gpl_compatible = -1;
182 mod->next = modules;
183 modules = mod;
184
185 return mod;
186}
187
188/* A hash of all exported symbols,
189 * struct symbol is also used for lists of unresolved symbols */
190
191#define SYMBOL_HASH_SIZE 1024
192
193struct symbol {
194 struct symbol *next;
195 struct module *module;
196 unsigned int crc;
197 int crc_valid;
198 char *namespace;
199 unsigned int weak:1;
200 unsigned int is_static:1; /* 1 if symbol is not global */
201 enum export export; /* Type of export */
202 char name[];
203};
204
205static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
206
207/* This is based on the hash algorithm from gdbm, via tdb */
208static inline unsigned int tdb_hash(const char *name)
209{
210 unsigned value; /* Used to compute the hash value. */
211 unsigned i; /* Used to cycle through random values. */
212
213 /* Set the initial value from the key size. */
214 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
215 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
216
217 return (1103515243 * value + 12345);
218}
219
220/**
221 * Allocate a new symbols for use in the hash of exported symbols or
222 * the list of unresolved symbols per module
223 **/
224static struct symbol *alloc_symbol(const char *name, unsigned int weak,
225 struct symbol *next)
226{
227 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
228
229 memset(s, 0, sizeof(*s));
230 strcpy(s->name, name);
231 s->weak = weak;
232 s->next = next;
233 s->is_static = 1;
234 return s;
235}
236
237/* For the hash of exported symbols */
238static struct symbol *new_symbol(const char *name, struct module *module,
239 enum export export)
240{
241 unsigned int hash;
242
243 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
244 symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
245
246 return symbolhash[hash];
247}
248
249static struct symbol *find_symbol(const char *name)
250{
251 struct symbol *s;
252
253 /* For our purposes, .foo matches foo. PPC64 needs this. */
254 if (name[0] == '.')
255 name++;
256
257 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
258 if (strcmp(s->name, name) == 0)
259 return s;
260 }
261 return NULL;
262}
263
264static bool contains_namespace(struct namespace_list *list,
265 const char *namespace)
266{
267 for (; list; list = list->next)
268 if (!strcmp(list->namespace, namespace))
269 return true;
270
271 return false;
272}
273
274static void add_namespace(struct namespace_list **list, const char *namespace)
275{
276 struct namespace_list *ns_entry;
277
278 if (!contains_namespace(*list, namespace)) {
279 ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
280 strlen(namespace) + 1));
281 strcpy(ns_entry->namespace, namespace);
282 ns_entry->next = *list;
283 *list = ns_entry;
284 }
285}
286
287static bool module_imports_namespace(struct module *module,
288 const char *namespace)
289{
290 return contains_namespace(module->imported_namespaces, namespace);
291}
292
293static const struct {
294 const char *str;
295 enum export export;
296} export_list[] = {
297 { .str = "EXPORT_SYMBOL", .export = export_plain },
298 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
299 { .str = "(unknown)", .export = export_unknown },
300};
301
302
303static const char *export_str(enum export ex)
304{
305 return export_list[ex].str;
306}
307
308static enum export export_no(const char *s)
309{
310 int i;
311
312 if (!s)
313 return export_unknown;
314 for (i = 0; export_list[i].export != export_unknown; i++) {
315 if (strcmp(export_list[i].str, s) == 0)
316 return export_list[i].export;
317 }
318 return export_unknown;
319}
320
321static void *sym_get_data_by_offset(const struct elf_info *info,
322 unsigned int secindex, unsigned long offset)
323{
324 Elf_Shdr *sechdr = &info->sechdrs[secindex];
325
326 if (info->hdr->e_type != ET_REL)
327 offset -= sechdr->sh_addr;
328
329 return (void *)info->hdr + sechdr->sh_offset + offset;
330}
331
332static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
333{
334 return sym_get_data_by_offset(info, get_secindex(info, sym),
335 sym->st_value);
336}
337
338static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
339{
340 return sym_get_data_by_offset(info, info->secindex_strings,
341 sechdr->sh_name);
342}
343
344static const char *sec_name(const struct elf_info *info, int secindex)
345{
346 return sech_name(info, &info->sechdrs[secindex]);
347}
348
349#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
350
351static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
352{
353 const char *secname = sec_name(elf, sec);
354
355 if (strstarts(secname, "___ksymtab+"))
356 return export_plain;
357 else if (strstarts(secname, "___ksymtab_gpl+"))
358 return export_gpl;
359 else
360 return export_unknown;
361}
362
363static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
364{
365 if (sec == elf->export_sec)
366 return export_plain;
367 else if (sec == elf->export_gpl_sec)
368 return export_gpl;
369 else
370 return export_unknown;
371}
372
373static const char *namespace_from_kstrtabns(const struct elf_info *info,
374 const Elf_Sym *sym)
375{
376 const char *value = sym_get_data(info, sym);
377 return value[0] ? value : NULL;
378}
379
380static void sym_update_namespace(const char *symname, const char *namespace)
381{
382 struct symbol *s = find_symbol(symname);
383
384 /*
385 * That symbol should have been created earlier and thus this is
386 * actually an assertion.
387 */
388 if (!s) {
389 error("Could not update namespace(%s) for symbol %s\n",
390 namespace, symname);
391 return;
392 }
393
394 free(s->namespace);
395 s->namespace =
396 namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
397}
398
399/**
400 * Add an exported symbol - it may have already been added without a
401 * CRC, in this case just update the CRC
402 **/
403static struct symbol *sym_add_exported(const char *name, struct module *mod,
404 enum export export)
405{
406 struct symbol *s = find_symbol(name);
407
408 if (!s) {
409 s = new_symbol(name, mod, export);
410 } else if (!external_module || s->module->is_vmlinux ||
411 s->module == mod) {
412 warn("%s: '%s' exported twice. Previous export was in %s%s\n",
413 mod->name, name, s->module->name,
414 s->module->is_vmlinux ? "" : ".ko");
415 return s;
416 }
417
418 s->module = mod;
419 s->export = export;
420 return s;
421}
422
423static void sym_set_crc(const char *name, unsigned int crc)
424{
425 struct symbol *s = find_symbol(name);
426
427 /*
428 * Ignore stand-alone __crc_*, which might be auto-generated symbols
429 * such as __*_veneer in ARM ELF.
430 */
431 if (!s)
432 return;
433
434 s->crc = crc;
435 s->crc_valid = 1;
436}
437
438static void *grab_file(const char *filename, size_t *size)
439{
440 struct stat st;
441 void *map = MAP_FAILED;
442 int fd;
443
444 fd = open(filename, O_RDONLY);
445 if (fd < 0)
446 return NULL;
447 if (fstat(fd, &st))
448 goto failed;
449
450 *size = st.st_size;
451 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
452
453failed:
454 close(fd);
455 if (map == MAP_FAILED)
456 return NULL;
457 return map;
458}
459
460static void release_file(void *file, size_t size)
461{
462 munmap(file, size);
463}
464
465static int parse_elf(struct elf_info *info, const char *filename)
466{
467 unsigned int i;
468 Elf_Ehdr *hdr;
469 Elf_Shdr *sechdrs;
470 Elf_Sym *sym;
471 const char *secstrings;
472 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
473
474 hdr = grab_file(filename, &info->size);
475 if (!hdr) {
476 if (ignore_missing_files) {
477 fprintf(stderr, "%s: %s (ignored)\n", filename,
478 strerror(errno));
479 return 0;
480 }
481 perror(filename);
482 exit(1);
483 }
484 info->hdr = hdr;
485 if (info->size < sizeof(*hdr)) {
486 /* file too small, assume this is an empty .o file */
487 return 0;
488 }
489 /* Is this a valid ELF file? */
490 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
491 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
492 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
493 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
494 /* Not an ELF file - silently ignore it */
495 return 0;
496 }
497 /* Fix endianness in ELF header */
498 hdr->e_type = TO_NATIVE(hdr->e_type);
499 hdr->e_machine = TO_NATIVE(hdr->e_machine);
500 hdr->e_version = TO_NATIVE(hdr->e_version);
501 hdr->e_entry = TO_NATIVE(hdr->e_entry);
502 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
503 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
504 hdr->e_flags = TO_NATIVE(hdr->e_flags);
505 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
506 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
507 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
508 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
509 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
510 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
511 sechdrs = (void *)hdr + hdr->e_shoff;
512 info->sechdrs = sechdrs;
513
514 /* Check if file offset is correct */
515 if (hdr->e_shoff > info->size) {
516 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
517 (unsigned long)hdr->e_shoff, filename, info->size);
518 return 0;
519 }
520
521 if (hdr->e_shnum == SHN_UNDEF) {
522 /*
523 * There are more than 64k sections,
524 * read count from .sh_size.
525 */
526 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
527 }
528 else {
529 info->num_sections = hdr->e_shnum;
530 }
531 if (hdr->e_shstrndx == SHN_XINDEX) {
532 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
533 }
534 else {
535 info->secindex_strings = hdr->e_shstrndx;
536 }
537
538 /* Fix endianness in section headers */
539 for (i = 0; i < info->num_sections; i++) {
540 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
541 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
542 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
543 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
544 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
545 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
546 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
547 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
548 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
549 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
550 }
551 /* Find symbol table. */
552 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
553 for (i = 1; i < info->num_sections; i++) {
554 const char *secname;
555 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
556
557 if (!nobits && sechdrs[i].sh_offset > info->size) {
558 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
559 "sizeof(*hrd)=%zu\n", filename,
560 (unsigned long)sechdrs[i].sh_offset,
561 sizeof(*hdr));
562 return 0;
563 }
564 secname = secstrings + sechdrs[i].sh_name;
565 if (strcmp(secname, ".modinfo") == 0) {
566 if (nobits)
567 fatal("%s has NOBITS .modinfo\n", filename);
568 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
569 info->modinfo_len = sechdrs[i].sh_size;
570 } else if (strcmp(secname, "__ksymtab") == 0)
571 info->export_sec = i;
572 else if (strcmp(secname, "__ksymtab_gpl") == 0)
573 info->export_gpl_sec = i;
574
575 if (sechdrs[i].sh_type == SHT_SYMTAB) {
576 unsigned int sh_link_idx;
577 symtab_idx = i;
578 info->symtab_start = (void *)hdr +
579 sechdrs[i].sh_offset;
580 info->symtab_stop = (void *)hdr +
581 sechdrs[i].sh_offset + sechdrs[i].sh_size;
582 sh_link_idx = sechdrs[i].sh_link;
583 info->strtab = (void *)hdr +
584 sechdrs[sh_link_idx].sh_offset;
585 }
586
587 /* 32bit section no. table? ("more than 64k sections") */
588 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
589 symtab_shndx_idx = i;
590 info->symtab_shndx_start = (void *)hdr +
591 sechdrs[i].sh_offset;
592 info->symtab_shndx_stop = (void *)hdr +
593 sechdrs[i].sh_offset + sechdrs[i].sh_size;
594 }
595 }
596 if (!info->symtab_start)
597 fatal("%s has no symtab?\n", filename);
598
599 /* Fix endianness in symbols */
600 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
601 sym->st_shndx = TO_NATIVE(sym->st_shndx);
602 sym->st_name = TO_NATIVE(sym->st_name);
603 sym->st_value = TO_NATIVE(sym->st_value);
604 sym->st_size = TO_NATIVE(sym->st_size);
605 }
606
607 if (symtab_shndx_idx != ~0U) {
608 Elf32_Word *p;
609 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
610 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
611 filename, sechdrs[symtab_shndx_idx].sh_link,
612 symtab_idx);
613 /* Fix endianness */
614 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
615 p++)
616 *p = TO_NATIVE(*p);
617 }
618
619 return 1;
620}
621
622static void parse_elf_finish(struct elf_info *info)
623{
624 release_file(info->hdr, info->size);
625}
626
627static int ignore_undef_symbol(struct elf_info *info, const char *symname)
628{
629 /* ignore __this_module, it will be resolved shortly */
630 if (strcmp(symname, "__this_module") == 0)
631 return 1;
632 /* ignore global offset table */
633 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
634 return 1;
635 if (info->hdr->e_machine == EM_PPC)
636 /* Special register function linked on all modules during final link of .ko */
637 if (strstarts(symname, "_restgpr_") ||
638 strstarts(symname, "_savegpr_") ||
639 strstarts(symname, "_rest32gpr_") ||
640 strstarts(symname, "_save32gpr_") ||
641 strstarts(symname, "_restvr_") ||
642 strstarts(symname, "_savevr_"))
643 return 1;
644 if (info->hdr->e_machine == EM_PPC64)
645 /* Special register function linked on all modules during final link of .ko */
646 if (strstarts(symname, "_restgpr0_") ||
647 strstarts(symname, "_savegpr0_") ||
648 strstarts(symname, "_restvr_") ||
649 strstarts(symname, "_savevr_") ||
650 strcmp(symname, ".TOC.") == 0)
651 return 1;
652 /* Do not ignore this symbol */
653 return 0;
654}
655
656static void handle_modversion(const struct module *mod,
657 const struct elf_info *info,
658 const Elf_Sym *sym, const char *symname)
659{
660 unsigned int crc;
661
662 if (sym->st_shndx == SHN_UNDEF) {
663 warn("EXPORT symbol \"%s\" [%s%s] version ...\n"
664 "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
665 symname, mod->name, mod->is_vmlinux ? "" : ".ko",
666 symname);
667
668 return;
669 }
670
671 if (sym->st_shndx == SHN_ABS) {
672 crc = sym->st_value;
673 } else {
674 unsigned int *crcp;
675
676 /* symbol points to the CRC in the ELF object */
677 crcp = sym_get_data(info, sym);
678 crc = TO_NATIVE(*crcp);
679 }
680 sym_set_crc(symname, crc);
681}
682
683static void handle_symbol(struct module *mod, struct elf_info *info,
684 const Elf_Sym *sym, const char *symname)
685{
686 enum export export;
687 const char *name;
688
689 if (strstarts(symname, "__ksymtab"))
690 export = export_from_secname(info, get_secindex(info, sym));
691 else
692 export = export_from_sec(info, get_secindex(info, sym));
693
694 switch (sym->st_shndx) {
695 case SHN_COMMON:
696 if (strstarts(symname, "__gnu_lto_")) {
697 /* Should warn here, but modpost runs before the linker */
698 } else
699 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
700 break;
701 case SHN_UNDEF:
702 /* undefined symbol */
703 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
704 ELF_ST_BIND(sym->st_info) != STB_WEAK)
705 break;
706 if (ignore_undef_symbol(info, symname))
707 break;
708 if (info->hdr->e_machine == EM_SPARC ||
709 info->hdr->e_machine == EM_SPARCV9) {
710 /* Ignore register directives. */
711 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
712 break;
713 if (symname[0] == '.') {
714 char *munged = NOFAIL(strdup(symname));
715 munged[0] = '_';
716 munged[1] = toupper(munged[1]);
717 symname = munged;
718 }
719 }
720
721 mod->unres = alloc_symbol(symname,
722 ELF_ST_BIND(sym->st_info) == STB_WEAK,
723 mod->unres);
724 break;
725 default:
726 /* All exported symbols */
727 if (strstarts(symname, "__ksymtab_")) {
728 name = symname + strlen("__ksymtab_");
729 sym_add_exported(name, mod, export);
730 }
731 if (strcmp(symname, "init_module") == 0)
732 mod->has_init = 1;
733 if (strcmp(symname, "cleanup_module") == 0)
734 mod->has_cleanup = 1;
735 break;
736 }
737}
738
739/**
740 * Parse tag=value strings from .modinfo section
741 **/
742static char *next_string(char *string, unsigned long *secsize)
743{
744 /* Skip non-zero chars */
745 while (string[0]) {
746 string++;
747 if ((*secsize)-- <= 1)
748 return NULL;
749 }
750
751 /* Skip any zero padding. */
752 while (!string[0]) {
753 string++;
754 if ((*secsize)-- <= 1)
755 return NULL;
756 }
757 return string;
758}
759
760static char *get_next_modinfo(struct elf_info *info, const char *tag,
761 char *prev)
762{
763 char *p;
764 unsigned int taglen = strlen(tag);
765 char *modinfo = info->modinfo;
766 unsigned long size = info->modinfo_len;
767
768 if (prev) {
769 size -= prev - modinfo;
770 modinfo = next_string(prev, &size);
771 }
772
773 for (p = modinfo; p; p = next_string(p, &size)) {
774 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
775 return p + taglen + 1;
776 }
777 return NULL;
778}
779
780static char *get_modinfo(struct elf_info *info, const char *tag)
781
782{
783 return get_next_modinfo(info, tag, NULL);
784}
785
786/**
787 * Test if string s ends in string sub
788 * return 0 if match
789 **/
790static int strrcmp(const char *s, const char *sub)
791{
792 int slen, sublen;
793
794 if (!s || !sub)
795 return 1;
796
797 slen = strlen(s);
798 sublen = strlen(sub);
799
800 if ((slen == 0) || (sublen == 0))
801 return 1;
802
803 if (sublen > slen)
804 return 1;
805
806 return memcmp(s + slen - sublen, sub, sublen);
807}
808
809static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
810{
811 if (sym)
812 return elf->strtab + sym->st_name;
813 else
814 return "(unknown)";
815}
816
817/* The pattern is an array of simple patterns.
818 * "foo" will match an exact string equal to "foo"
819 * "*foo" will match a string that ends with "foo"
820 * "foo*" will match a string that begins with "foo"
821 * "*foo*" will match a string that contains "foo"
822 */
823static int match(const char *sym, const char * const pat[])
824{
825 const char *p;
826 while (*pat) {
827 p = *pat++;
828 const char *endp = p + strlen(p) - 1;
829
830 /* "*foo*" */
831 if (*p == '*' && *endp == '*') {
832 char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
833 char *here = strstr(sym, bare);
834
835 free(bare);
836 if (here != NULL)
837 return 1;
838 }
839 /* "*foo" */
840 else if (*p == '*') {
841 if (strrcmp(sym, p + 1) == 0)
842 return 1;
843 }
844 /* "foo*" */
845 else if (*endp == '*') {
846 if (strncmp(sym, p, strlen(p) - 1) == 0)
847 return 1;
848 }
849 /* no wildcards */
850 else {
851 if (strcmp(p, sym) == 0)
852 return 1;
853 }
854 }
855 /* no match */
856 return 0;
857}
858
859/* sections that we do not want to do full section mismatch check on */
860static const char *const section_white_list[] =
861{
862 ".comment*",
863 ".debug*",
864 ".cranges", /* sh64 */
865 ".zdebug*", /* Compressed debug sections. */
866 ".GCC.command.line", /* record-gcc-switches */
867 ".mdebug*", /* alpha, score, mips etc. */
868 ".pdr", /* alpha, score, mips etc. */
869 ".stab*",
870 ".note*",
871 ".got*",
872 ".toc*",
873 ".xt.prop", /* xtensa */
874 ".xt.lit", /* xtensa */
875 ".arcextmap*", /* arc */
876 ".gnu.linkonce.arcext*", /* arc : modules */
877 ".cmem*", /* EZchip */
878 ".fmt_slot*", /* EZchip */
879 ".gnu.lto*",
880 ".discard.*",
881 NULL
882};
883
884/*
885 * This is used to find sections missing the SHF_ALLOC flag.
886 * The cause of this is often a section specified in assembler
887 * without "ax" / "aw".
888 */
889static void check_section(const char *modname, struct elf_info *elf,
890 Elf_Shdr *sechdr)
891{
892 const char *sec = sech_name(elf, sechdr);
893
894 if (sechdr->sh_type == SHT_PROGBITS &&
895 !(sechdr->sh_flags & SHF_ALLOC) &&
896 !match(sec, section_white_list)) {
897 warn("%s (%s): unexpected non-allocatable section.\n"
898 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
899 "Note that for example <linux/init.h> contains\n"
900 "section definitions for use in .S files.\n\n",
901 modname, sec);
902 }
903}
904
905
906
907#define ALL_INIT_DATA_SECTIONS \
908 ".init.setup", ".init.rodata", ".meminit.rodata", \
909 ".init.data", ".meminit.data"
910#define ALL_EXIT_DATA_SECTIONS \
911 ".exit.data", ".memexit.data"
912
913#define ALL_INIT_TEXT_SECTIONS \
914 ".init.text", ".meminit.text"
915#define ALL_EXIT_TEXT_SECTIONS \
916 ".exit.text", ".memexit.text"
917
918#define ALL_PCI_INIT_SECTIONS \
919 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
920 ".pci_fixup_enable", ".pci_fixup_resume", \
921 ".pci_fixup_resume_early", ".pci_fixup_suspend"
922
923#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
924#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
925
926#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
927#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
928
929#define DATA_SECTIONS ".data", ".data.rel"
930#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
931 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
932#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
933 ".fixup", ".entry.text", ".exception.text", ".text.*", \
934 ".coldtext"
935
936#define INIT_SECTIONS ".init.*"
937#define MEM_INIT_SECTIONS ".meminit.*"
938
939#define EXIT_SECTIONS ".exit.*"
940#define MEM_EXIT_SECTIONS ".memexit.*"
941
942#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
943 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
944
945/* init data sections */
946static const char *const init_data_sections[] =
947 { ALL_INIT_DATA_SECTIONS, NULL };
948
949/* all init sections */
950static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
951
952/* All init and exit sections (code + data) */
953static const char *const init_exit_sections[] =
954 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
955
956/* all text sections */
957static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
958
959/* data section */
960static const char *const data_sections[] = { DATA_SECTIONS, NULL };
961
962
963/* symbols in .data that may refer to init/exit sections */
964#define DEFAULT_SYMBOL_WHITE_LIST \
965 "*driver", \
966 "*_template", /* scsi uses *_template a lot */ \
967 "*_timer", /* arm uses ops structures named _timer a lot */ \
968 "*_sht", /* scsi also used *_sht to some extent */ \
969 "*_ops", \
970 "*_probe", \
971 "*_probe_one", \
972 "*_console"
973
974static const char *const head_sections[] = { ".head.text*", NULL };
975static const char *const linker_symbols[] =
976 { "__init_begin", "_sinittext", "_einittext", NULL };
977static const char *const optim_symbols[] = { "*.constprop.*", NULL };
978
979enum mismatch {
980 TEXT_TO_ANY_INIT,
981 DATA_TO_ANY_INIT,
982 TEXT_TO_ANY_EXIT,
983 DATA_TO_ANY_EXIT,
984 XXXINIT_TO_SOME_INIT,
985 XXXEXIT_TO_SOME_EXIT,
986 ANY_INIT_TO_ANY_EXIT,
987 ANY_EXIT_TO_ANY_INIT,
988 EXPORT_TO_INIT_EXIT,
989 EXTABLE_TO_NON_TEXT,
990};
991
992/**
993 * Describe how to match sections on different criteria:
994 *
995 * @fromsec: Array of sections to be matched.
996 *
997 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
998 * this array is forbidden (black-list). Can be empty.
999 *
1000 * @good_tosec: Relocations applied to a section in @fromsec must be
1001 * targeting sections in this array (white-list). Can be empty.
1002 *
1003 * @mismatch: Type of mismatch.
1004 *
1005 * @symbol_white_list: Do not match a relocation to a symbol in this list
1006 * even if it is targeting a section in @bad_to_sec.
1007 *
1008 * @handler: Specific handler to call when a match is found. If NULL,
1009 * default_mismatch_handler() will be called.
1010 *
1011 */
1012struct sectioncheck {
1013 const char *fromsec[20];
1014 const char *bad_tosec[20];
1015 const char *good_tosec[20];
1016 enum mismatch mismatch;
1017 const char *symbol_white_list[20];
1018 void (*handler)(const char *modname, struct elf_info *elf,
1019 const struct sectioncheck* const mismatch,
1020 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1021
1022};
1023
1024static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1025 const struct sectioncheck* const mismatch,
1026 Elf_Rela *r, Elf_Sym *sym,
1027 const char *fromsec);
1028
1029static const struct sectioncheck sectioncheck[] = {
1030/* Do not reference init/exit code/data from
1031 * normal code and data
1032 */
1033{
1034 .fromsec = { TEXT_SECTIONS, NULL },
1035 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1036 .mismatch = TEXT_TO_ANY_INIT,
1037 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1038},
1039{
1040 .fromsec = { DATA_SECTIONS, NULL },
1041 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1042 .mismatch = DATA_TO_ANY_INIT,
1043 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1044},
1045{
1046 .fromsec = { DATA_SECTIONS, NULL },
1047 .bad_tosec = { INIT_SECTIONS, NULL },
1048 .mismatch = DATA_TO_ANY_INIT,
1049 .symbol_white_list = {
1050 "*_template", "*_timer", "*_sht", "*_ops",
1051 "*_probe", "*_probe_one", "*_console", NULL
1052 },
1053},
1054{
1055 .fromsec = { TEXT_SECTIONS, NULL },
1056 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1057 .mismatch = TEXT_TO_ANY_EXIT,
1058 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1059},
1060{
1061 .fromsec = { DATA_SECTIONS, NULL },
1062 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1063 .mismatch = DATA_TO_ANY_EXIT,
1064 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1065},
1066/* Do not reference init code/data from meminit code/data */
1067{
1068 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1069 .bad_tosec = { INIT_SECTIONS, NULL },
1070 .mismatch = XXXINIT_TO_SOME_INIT,
1071 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1072},
1073/* Do not reference exit code/data from memexit code/data */
1074{
1075 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1076 .bad_tosec = { EXIT_SECTIONS, NULL },
1077 .mismatch = XXXEXIT_TO_SOME_EXIT,
1078 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1079},
1080/* Do not use exit code/data from init code */
1081{
1082 .fromsec = { ALL_INIT_SECTIONS, NULL },
1083 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1084 .mismatch = ANY_INIT_TO_ANY_EXIT,
1085 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1086},
1087/* Do not use init code/data from exit code */
1088{
1089 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1090 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1091 .mismatch = ANY_EXIT_TO_ANY_INIT,
1092 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1093},
1094{
1095 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1096 .bad_tosec = { INIT_SECTIONS, NULL },
1097 .mismatch = ANY_INIT_TO_ANY_EXIT,
1098 .symbol_white_list = { NULL },
1099},
1100/* Do not export init/exit functions or data */
1101{
1102 .fromsec = { "__ksymtab*", NULL },
1103 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1104 .mismatch = EXPORT_TO_INIT_EXIT,
1105 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1106},
1107{
1108 .fromsec = { "__ex_table", NULL },
1109 /* If you're adding any new black-listed sections in here, consider
1110 * adding a special 'printer' for them in scripts/check_extable.
1111 */
1112 .bad_tosec = { ".altinstr_replacement", NULL },
1113 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1114 .mismatch = EXTABLE_TO_NON_TEXT,
1115 .handler = extable_mismatch_handler,
1116}
1117};
1118
1119static const struct sectioncheck *section_mismatch(
1120 const char *fromsec, const char *tosec)
1121{
1122 int i;
1123 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1124 const struct sectioncheck *check = §ioncheck[0];
1125
1126 /*
1127 * The target section could be the SHT_NUL section when we're
1128 * handling relocations to un-resolved symbols, trying to match it
1129 * doesn't make much sense and causes build failures on parisc
1130 * architectures.
1131 */
1132 if (*tosec == '\0')
1133 return NULL;
1134
1135 for (i = 0; i < elems; i++) {
1136 if (match(fromsec, check->fromsec)) {
1137 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1138 return check;
1139 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1140 return check;
1141 }
1142 check++;
1143 }
1144 return NULL;
1145}
1146
1147/**
1148 * Whitelist to allow certain references to pass with no warning.
1149 *
1150 * Pattern 1:
1151 * If a module parameter is declared __initdata and permissions=0
1152 * then this is legal despite the warning generated.
1153 * We cannot see value of permissions here, so just ignore
1154 * this pattern.
1155 * The pattern is identified by:
1156 * tosec = .init.data
1157 * fromsec = .data*
1158 * atsym =__param*
1159 *
1160 * Pattern 1a:
1161 * module_param_call() ops can refer to __init set function if permissions=0
1162 * The pattern is identified by:
1163 * tosec = .init.text
1164 * fromsec = .data*
1165 * atsym = __param_ops_*
1166 *
1167 * Pattern 2:
1168 * Many drivers utilise a *driver container with references to
1169 * add, remove, probe functions etc.
1170 * the pattern is identified by:
1171 * tosec = init or exit section
1172 * fromsec = data section
1173 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1174 * *probe_one, *_console, *_timer
1175 *
1176 * Pattern 3:
1177 * Whitelist all references from .head.text to any init section
1178 *
1179 * Pattern 4:
1180 * Some symbols belong to init section but still it is ok to reference
1181 * these from non-init sections as these symbols don't have any memory
1182 * allocated for them and symbol address and value are same. So even
1183 * if init section is freed, its ok to reference those symbols.
1184 * For ex. symbols marking the init section boundaries.
1185 * This pattern is identified by
1186 * refsymname = __init_begin, _sinittext, _einittext
1187 *
1188 * Pattern 5:
1189 * GCC may optimize static inlines when fed constant arg(s) resulting
1190 * in functions like cpumask_empty() -- generating an associated symbol
1191 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1192 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1193 * meaningless section warning. May need to add isra symbols too...
1194 * This pattern is identified by
1195 * tosec = init section
1196 * fromsec = text section
1197 * refsymname = *.constprop.*
1198 *
1199 * Pattern 6:
1200 * Hide section mismatch warnings for ELF local symbols. The goal
1201 * is to eliminate false positive modpost warnings caused by
1202 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1203 * Autogenerated symbol names bypass modpost's "Pattern 2"
1204 * whitelisting, which relies on pattern-matching against symbol
1205 * names to work. (One situation where gcc can autogenerate ELF
1206 * local symbols is when "-fsection-anchors" is used.)
1207 **/
1208static int secref_whitelist(const struct sectioncheck *mismatch,
1209 const char *fromsec, const char *fromsym,
1210 const char *tosec, const char *tosym)
1211{
1212 /* Check for pattern 1 */
1213 if (match(tosec, init_data_sections) &&
1214 match(fromsec, data_sections) &&
1215 strstarts(fromsym, "__param"))
1216 return 0;
1217
1218 /* Check for pattern 1a */
1219 if (strcmp(tosec, ".init.text") == 0 &&
1220 match(fromsec, data_sections) &&
1221 strstarts(fromsym, "__param_ops_"))
1222 return 0;
1223
1224 /* Check for pattern 2 */
1225 if (match(tosec, init_exit_sections) &&
1226 match(fromsec, data_sections) &&
1227 match(fromsym, mismatch->symbol_white_list))
1228 return 0;
1229
1230 /* Check for pattern 3 */
1231 if (match(fromsec, head_sections) &&
1232 match(tosec, init_sections))
1233 return 0;
1234
1235 /* Check for pattern 4 */
1236 if (match(tosym, linker_symbols))
1237 return 0;
1238
1239 /* Check for pattern 5 */
1240 if (match(fromsec, text_sections) &&
1241 match(tosec, init_sections) &&
1242 match(fromsym, optim_symbols))
1243 return 0;
1244
1245 /* Check for pattern 6 */
1246 if (strstarts(fromsym, ".L"))
1247 return 0;
1248
1249 return 1;
1250}
1251
1252static inline int is_arm_mapping_symbol(const char *str)
1253{
1254 return str[0] == '$' && strchr("axtd", str[1])
1255 && (str[2] == '\0' || str[2] == '.');
1256}
1257
1258/*
1259 * If there's no name there, ignore it; likewise, ignore it if it's
1260 * one of the magic symbols emitted used by current ARM tools.
1261 *
1262 * Otherwise if find_symbols_between() returns those symbols, they'll
1263 * fail the whitelist tests and cause lots of false alarms ... fixable
1264 * only by merging __exit and __init sections into __text, bloating
1265 * the kernel (which is especially evil on embedded platforms).
1266 */
1267static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1268{
1269 const char *name = elf->strtab + sym->st_name;
1270
1271 if (!name || !strlen(name))
1272 return 0;
1273 return !is_arm_mapping_symbol(name);
1274}
1275
1276/**
1277 * Find symbol based on relocation record info.
1278 * In some cases the symbol supplied is a valid symbol so
1279 * return refsym. If st_name != 0 we assume this is a valid symbol.
1280 * In other cases the symbol needs to be looked up in the symbol table
1281 * based on section and address.
1282 * **/
1283static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1284 Elf_Sym *relsym)
1285{
1286 Elf_Sym *sym;
1287 Elf_Sym *near = NULL;
1288 Elf64_Sword distance = 20;
1289 Elf64_Sword d;
1290 unsigned int relsym_secindex;
1291
1292 if (relsym->st_name != 0)
1293 return relsym;
1294
1295 relsym_secindex = get_secindex(elf, relsym);
1296 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1297 if (get_secindex(elf, sym) != relsym_secindex)
1298 continue;
1299 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1300 continue;
1301 if (!is_valid_name(elf, sym))
1302 continue;
1303 if (sym->st_value == addr)
1304 return sym;
1305 /* Find a symbol nearby - addr are maybe negative */
1306 d = sym->st_value - addr;
1307 if (d < 0)
1308 d = addr - sym->st_value;
1309 if (d < distance) {
1310 distance = d;
1311 near = sym;
1312 }
1313 }
1314 /* We need a close match */
1315 if (distance < 20)
1316 return near;
1317 else
1318 return NULL;
1319}
1320
1321/*
1322 * Find symbols before or equal addr and after addr - in the section sec.
1323 * If we find two symbols with equal offset prefer one with a valid name.
1324 * The ELF format may have a better way to detect what type of symbol
1325 * it is, but this works for now.
1326 **/
1327static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1328 const char *sec)
1329{
1330 Elf_Sym *sym;
1331 Elf_Sym *near = NULL;
1332 Elf_Addr distance = ~0;
1333
1334 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1335 const char *symsec;
1336
1337 if (is_shndx_special(sym->st_shndx))
1338 continue;
1339 symsec = sec_name(elf, get_secindex(elf, sym));
1340 if (strcmp(symsec, sec) != 0)
1341 continue;
1342 if (!is_valid_name(elf, sym))
1343 continue;
1344 if (sym->st_value <= addr) {
1345 if ((addr - sym->st_value) < distance) {
1346 distance = addr - sym->st_value;
1347 near = sym;
1348 } else if ((addr - sym->st_value) == distance) {
1349 near = sym;
1350 }
1351 }
1352 }
1353 return near;
1354}
1355
1356/*
1357 * Convert a section name to the function/data attribute
1358 * .init.text => __init
1359 * .memexitconst => __memconst
1360 * etc.
1361 *
1362 * The memory of returned value has been allocated on a heap. The user of this
1363 * method should free it after usage.
1364*/
1365static char *sec2annotation(const char *s)
1366{
1367 if (match(s, init_exit_sections)) {
1368 char *p = NOFAIL(malloc(20));
1369 char *r = p;
1370
1371 *p++ = '_';
1372 *p++ = '_';
1373 if (*s == '.')
1374 s++;
1375 while (*s && *s != '.')
1376 *p++ = *s++;
1377 *p = '\0';
1378 if (*s == '.')
1379 s++;
1380 if (strstr(s, "rodata") != NULL)
1381 strcat(p, "const ");
1382 else if (strstr(s, "data") != NULL)
1383 strcat(p, "data ");
1384 else
1385 strcat(p, " ");
1386 return r;
1387 } else {
1388 return NOFAIL(strdup(""));
1389 }
1390}
1391
1392static int is_function(Elf_Sym *sym)
1393{
1394 if (sym)
1395 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1396 else
1397 return -1;
1398}
1399
1400static void print_section_list(const char * const list[20])
1401{
1402 const char *const *s = list;
1403
1404 while (*s) {
1405 fprintf(stderr, "%s", *s);
1406 s++;
1407 if (*s)
1408 fprintf(stderr, ", ");
1409 }
1410 fprintf(stderr, "\n");
1411}
1412
1413static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1414{
1415 switch (is_func) {
1416 case 0: *name = "variable"; *name_p = ""; break;
1417 case 1: *name = "function"; *name_p = "()"; break;
1418 default: *name = "(unknown reference)"; *name_p = ""; break;
1419 }
1420}
1421
1422/*
1423 * Print a warning about a section mismatch.
1424 * Try to find symbols near it so user can find it.
1425 * Check whitelist before warning - it may be a false positive.
1426 */
1427static void report_sec_mismatch(const char *modname,
1428 const struct sectioncheck *mismatch,
1429 const char *fromsec,
1430 unsigned long long fromaddr,
1431 const char *fromsym,
1432 int from_is_func,
1433 const char *tosec, const char *tosym,
1434 int to_is_func)
1435{
1436 const char *from, *from_p;
1437 const char *to, *to_p;
1438 char *prl_from;
1439 char *prl_to;
1440
1441 sec_mismatch_count++;
1442
1443 get_pretty_name(from_is_func, &from, &from_p);
1444 get_pretty_name(to_is_func, &to, &to_p);
1445
1446 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1447 "to the %s %s:%s%s\n",
1448 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1449 tosym, to_p);
1450
1451 switch (mismatch->mismatch) {
1452 case TEXT_TO_ANY_INIT:
1453 prl_from = sec2annotation(fromsec);
1454 prl_to = sec2annotation(tosec);
1455 fprintf(stderr,
1456 "The function %s%s() references\n"
1457 "the %s %s%s%s.\n"
1458 "This is often because %s lacks a %s\n"
1459 "annotation or the annotation of %s is wrong.\n",
1460 prl_from, fromsym,
1461 to, prl_to, tosym, to_p,
1462 fromsym, prl_to, tosym);
1463 free(prl_from);
1464 free(prl_to);
1465 break;
1466 case DATA_TO_ANY_INIT: {
1467 prl_to = sec2annotation(tosec);
1468 fprintf(stderr,
1469 "The variable %s references\n"
1470 "the %s %s%s%s\n"
1471 "If the reference is valid then annotate the\n"
1472 "variable with __init* or __refdata (see linux/init.h) "
1473 "or name the variable:\n",
1474 fromsym, to, prl_to, tosym, to_p);
1475 print_section_list(mismatch->symbol_white_list);
1476 free(prl_to);
1477 break;
1478 }
1479 case TEXT_TO_ANY_EXIT:
1480 prl_to = sec2annotation(tosec);
1481 fprintf(stderr,
1482 "The function %s() references a %s in an exit section.\n"
1483 "Often the %s %s%s has valid usage outside the exit section\n"
1484 "and the fix is to remove the %sannotation of %s.\n",
1485 fromsym, to, to, tosym, to_p, prl_to, tosym);
1486 free(prl_to);
1487 break;
1488 case DATA_TO_ANY_EXIT: {
1489 prl_to = sec2annotation(tosec);
1490 fprintf(stderr,
1491 "The variable %s references\n"
1492 "the %s %s%s%s\n"
1493 "If the reference is valid then annotate the\n"
1494 "variable with __exit* (see linux/init.h) or "
1495 "name the variable:\n",
1496 fromsym, to, prl_to, tosym, to_p);
1497 print_section_list(mismatch->symbol_white_list);
1498 free(prl_to);
1499 break;
1500 }
1501 case XXXINIT_TO_SOME_INIT:
1502 case XXXEXIT_TO_SOME_EXIT:
1503 prl_from = sec2annotation(fromsec);
1504 prl_to = sec2annotation(tosec);
1505 fprintf(stderr,
1506 "The %s %s%s%s references\n"
1507 "a %s %s%s%s.\n"
1508 "If %s is only used by %s then\n"
1509 "annotate %s with a matching annotation.\n",
1510 from, prl_from, fromsym, from_p,
1511 to, prl_to, tosym, to_p,
1512 tosym, fromsym, tosym);
1513 free(prl_from);
1514 free(prl_to);
1515 break;
1516 case ANY_INIT_TO_ANY_EXIT:
1517 prl_from = sec2annotation(fromsec);
1518 prl_to = sec2annotation(tosec);
1519 fprintf(stderr,
1520 "The %s %s%s%s references\n"
1521 "a %s %s%s%s.\n"
1522 "This is often seen when error handling "
1523 "in the init function\n"
1524 "uses functionality in the exit path.\n"
1525 "The fix is often to remove the %sannotation of\n"
1526 "%s%s so it may be used outside an exit section.\n",
1527 from, prl_from, fromsym, from_p,
1528 to, prl_to, tosym, to_p,
1529 prl_to, tosym, to_p);
1530 free(prl_from);
1531 free(prl_to);
1532 break;
1533 case ANY_EXIT_TO_ANY_INIT:
1534 prl_from = sec2annotation(fromsec);
1535 prl_to = sec2annotation(tosec);
1536 fprintf(stderr,
1537 "The %s %s%s%s references\n"
1538 "a %s %s%s%s.\n"
1539 "This is often seen when error handling "
1540 "in the exit function\n"
1541 "uses functionality in the init path.\n"
1542 "The fix is often to remove the %sannotation of\n"
1543 "%s%s so it may be used outside an init section.\n",
1544 from, prl_from, fromsym, from_p,
1545 to, prl_to, tosym, to_p,
1546 prl_to, tosym, to_p);
1547 free(prl_from);
1548 free(prl_to);
1549 break;
1550 case EXPORT_TO_INIT_EXIT:
1551 prl_to = sec2annotation(tosec);
1552 fprintf(stderr,
1553 "The symbol %s is exported and annotated %s\n"
1554 "Fix this by removing the %sannotation of %s "
1555 "or drop the export.\n",
1556 tosym, prl_to, prl_to, tosym);
1557 free(prl_to);
1558 break;
1559 case EXTABLE_TO_NON_TEXT:
1560 fatal("There's a special handler for this mismatch type, "
1561 "we should never get here.");
1562 break;
1563 }
1564 fprintf(stderr, "\n");
1565}
1566
1567static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1568 const struct sectioncheck* const mismatch,
1569 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1570{
1571 const char *tosec;
1572 Elf_Sym *to;
1573 Elf_Sym *from;
1574 const char *tosym;
1575 const char *fromsym;
1576
1577 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1578 fromsym = sym_name(elf, from);
1579
1580 if (strstarts(fromsym, "reference___initcall"))
1581 return;
1582
1583 tosec = sec_name(elf, get_secindex(elf, sym));
1584 to = find_elf_symbol(elf, r->r_addend, sym);
1585 tosym = sym_name(elf, to);
1586
1587 /* check whitelist - we may ignore it */
1588 if (secref_whitelist(mismatch,
1589 fromsec, fromsym, tosec, tosym)) {
1590 report_sec_mismatch(modname, mismatch,
1591 fromsec, r->r_offset, fromsym,
1592 is_function(from), tosec, tosym,
1593 is_function(to));
1594 }
1595}
1596
1597static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1598{
1599 if (section_index > elf->num_sections)
1600 fatal("section_index is outside elf->num_sections!\n");
1601
1602 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1603}
1604
1605/*
1606 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1607 * to know the sizeof(struct exception_table_entry) for the target architecture.
1608 */
1609static unsigned int extable_entry_size = 0;
1610static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1611{
1612 /*
1613 * If we're currently checking the second relocation within __ex_table,
1614 * that relocation offset tells us the offsetof(struct
1615 * exception_table_entry, fixup) which is equal to sizeof(struct
1616 * exception_table_entry) divided by two. We use that to our advantage
1617 * since there's no portable way to get that size as every architecture
1618 * seems to go with different sized types. Not pretty but better than
1619 * hard-coding the size for every architecture..
1620 */
1621 if (!extable_entry_size)
1622 extable_entry_size = r->r_offset * 2;
1623}
1624
1625static inline bool is_extable_fault_address(Elf_Rela *r)
1626{
1627 /*
1628 * extable_entry_size is only discovered after we've handled the
1629 * _second_ relocation in __ex_table, so only abort when we're not
1630 * handling the first reloc and extable_entry_size is zero.
1631 */
1632 if (r->r_offset && extable_entry_size == 0)
1633 fatal("extable_entry size hasn't been discovered!\n");
1634
1635 return ((r->r_offset == 0) ||
1636 (r->r_offset % extable_entry_size == 0));
1637}
1638
1639#define is_second_extable_reloc(Start, Cur, Sec) \
1640 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1641
1642static void report_extable_warnings(const char* modname, struct elf_info* elf,
1643 const struct sectioncheck* const mismatch,
1644 Elf_Rela* r, Elf_Sym* sym,
1645 const char* fromsec, const char* tosec)
1646{
1647 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1648 const char* fromsym_name = sym_name(elf, fromsym);
1649 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1650 const char* tosym_name = sym_name(elf, tosym);
1651 const char* from_pretty_name;
1652 const char* from_pretty_name_p;
1653 const char* to_pretty_name;
1654 const char* to_pretty_name_p;
1655
1656 get_pretty_name(is_function(fromsym),
1657 &from_pretty_name, &from_pretty_name_p);
1658 get_pretty_name(is_function(tosym),
1659 &to_pretty_name, &to_pretty_name_p);
1660
1661 warn("%s(%s+0x%lx): Section mismatch in reference"
1662 " from the %s %s%s to the %s %s:%s%s\n",
1663 modname, fromsec, (long)r->r_offset, from_pretty_name,
1664 fromsym_name, from_pretty_name_p,
1665 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1666
1667 if (!match(tosec, mismatch->bad_tosec) &&
1668 is_executable_section(elf, get_secindex(elf, sym)))
1669 fprintf(stderr,
1670 "The relocation at %s+0x%lx references\n"
1671 "section \"%s\" which is not in the list of\n"
1672 "authorized sections. If you're adding a new section\n"
1673 "and/or if this reference is valid, add \"%s\" to the\n"
1674 "list of authorized sections to jump to on fault.\n"
1675 "This can be achieved by adding \"%s\" to \n"
1676 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1677 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1678}
1679
1680static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1681 const struct sectioncheck* const mismatch,
1682 Elf_Rela* r, Elf_Sym* sym,
1683 const char *fromsec)
1684{
1685 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1686
1687 sec_mismatch_count++;
1688
1689 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
1690
1691 if (match(tosec, mismatch->bad_tosec))
1692 fatal("The relocation at %s+0x%lx references\n"
1693 "section \"%s\" which is black-listed.\n"
1694 "Something is seriously wrong and should be fixed.\n"
1695 "You might get more information about where this is\n"
1696 "coming from by using scripts/check_extable.sh %s\n",
1697 fromsec, (long)r->r_offset, tosec, modname);
1698 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1699 if (is_extable_fault_address(r))
1700 fatal("The relocation at %s+0x%lx references\n"
1701 "section \"%s\" which is not executable, IOW\n"
1702 "it is not possible for the kernel to fault\n"
1703 "at that address. Something is seriously wrong\n"
1704 "and should be fixed.\n",
1705 fromsec, (long)r->r_offset, tosec);
1706 else
1707 fatal("The relocation at %s+0x%lx references\n"
1708 "section \"%s\" which is not executable, IOW\n"
1709 "the kernel will fault if it ever tries to\n"
1710 "jump to it. Something is seriously wrong\n"
1711 "and should be fixed.\n",
1712 fromsec, (long)r->r_offset, tosec);
1713 }
1714}
1715
1716static void check_section_mismatch(const char *modname, struct elf_info *elf,
1717 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1718{
1719 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1720 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1721
1722 if (mismatch) {
1723 if (mismatch->handler)
1724 mismatch->handler(modname, elf, mismatch,
1725 r, sym, fromsec);
1726 else
1727 default_mismatch_handler(modname, elf, mismatch,
1728 r, sym, fromsec);
1729 }
1730}
1731
1732static unsigned int *reloc_location(struct elf_info *elf,
1733 Elf_Shdr *sechdr, Elf_Rela *r)
1734{
1735 return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset);
1736}
1737
1738static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1739{
1740 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1741 unsigned int *location = reloc_location(elf, sechdr, r);
1742
1743 switch (r_typ) {
1744 case R_386_32:
1745 r->r_addend = TO_NATIVE(*location);
1746 break;
1747 case R_386_PC32:
1748 r->r_addend = TO_NATIVE(*location) + 4;
1749 /* For CONFIG_RELOCATABLE=y */
1750 if (elf->hdr->e_type == ET_EXEC)
1751 r->r_addend += r->r_offset;
1752 break;
1753 }
1754 return 0;
1755}
1756
1757#ifndef R_ARM_CALL
1758#define R_ARM_CALL 28
1759#endif
1760#ifndef R_ARM_JUMP24
1761#define R_ARM_JUMP24 29
1762#endif
1763
1764#ifndef R_ARM_THM_CALL
1765#define R_ARM_THM_CALL 10
1766#endif
1767#ifndef R_ARM_THM_JUMP24
1768#define R_ARM_THM_JUMP24 30
1769#endif
1770#ifndef R_ARM_THM_JUMP19
1771#define R_ARM_THM_JUMP19 51
1772#endif
1773
1774static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1775{
1776 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1777
1778 switch (r_typ) {
1779 case R_ARM_ABS32:
1780 /* From ARM ABI: (S + A) | T */
1781 r->r_addend = (int)(long)
1782 (elf->symtab_start + ELF_R_SYM(r->r_info));
1783 break;
1784 case R_ARM_PC24:
1785 case R_ARM_CALL:
1786 case R_ARM_JUMP24:
1787 case R_ARM_THM_CALL:
1788 case R_ARM_THM_JUMP24:
1789 case R_ARM_THM_JUMP19:
1790 /* From ARM ABI: ((S + A) | T) - P */
1791 r->r_addend = (int)(long)(elf->hdr +
1792 sechdr->sh_offset +
1793 (r->r_offset - sechdr->sh_addr));
1794 break;
1795 default:
1796 return 1;
1797 }
1798 return 0;
1799}
1800
1801static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1802{
1803 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1804 unsigned int *location = reloc_location(elf, sechdr, r);
1805 unsigned int inst;
1806
1807 if (r_typ == R_MIPS_HI16)
1808 return 1; /* skip this */
1809 inst = TO_NATIVE(*location);
1810 switch (r_typ) {
1811 case R_MIPS_LO16:
1812 r->r_addend = inst & 0xffff;
1813 break;
1814 case R_MIPS_26:
1815 r->r_addend = (inst & 0x03ffffff) << 2;
1816 break;
1817 case R_MIPS_32:
1818 r->r_addend = inst;
1819 break;
1820 }
1821 return 0;
1822}
1823
1824static void section_rela(const char *modname, struct elf_info *elf,
1825 Elf_Shdr *sechdr)
1826{
1827 Elf_Sym *sym;
1828 Elf_Rela *rela;
1829 Elf_Rela r;
1830 unsigned int r_sym;
1831 const char *fromsec;
1832
1833 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1834 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1835
1836 fromsec = sech_name(elf, sechdr);
1837 fromsec += strlen(".rela");
1838 /* if from section (name) is know good then skip it */
1839 if (match(fromsec, section_white_list))
1840 return;
1841
1842 for (rela = start; rela < stop; rela++) {
1843 r.r_offset = TO_NATIVE(rela->r_offset);
1844#if KERNEL_ELFCLASS == ELFCLASS64
1845 if (elf->hdr->e_machine == EM_MIPS) {
1846 unsigned int r_typ;
1847 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1848 r_sym = TO_NATIVE(r_sym);
1849 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1850 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1851 } else {
1852 r.r_info = TO_NATIVE(rela->r_info);
1853 r_sym = ELF_R_SYM(r.r_info);
1854 }
1855#else
1856 r.r_info = TO_NATIVE(rela->r_info);
1857 r_sym = ELF_R_SYM(r.r_info);
1858#endif
1859 r.r_addend = TO_NATIVE(rela->r_addend);
1860 sym = elf->symtab_start + r_sym;
1861 /* Skip special sections */
1862 if (is_shndx_special(sym->st_shndx))
1863 continue;
1864 if (is_second_extable_reloc(start, rela, fromsec))
1865 find_extable_entry_size(fromsec, &r);
1866 check_section_mismatch(modname, elf, &r, sym, fromsec);
1867 }
1868}
1869
1870static void section_rel(const char *modname, struct elf_info *elf,
1871 Elf_Shdr *sechdr)
1872{
1873 Elf_Sym *sym;
1874 Elf_Rel *rel;
1875 Elf_Rela r;
1876 unsigned int r_sym;
1877 const char *fromsec;
1878
1879 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1880 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1881
1882 fromsec = sech_name(elf, sechdr);
1883 fromsec += strlen(".rel");
1884 /* if from section (name) is know good then skip it */
1885 if (match(fromsec, section_white_list))
1886 return;
1887
1888 for (rel = start; rel < stop; rel++) {
1889 r.r_offset = TO_NATIVE(rel->r_offset);
1890#if KERNEL_ELFCLASS == ELFCLASS64
1891 if (elf->hdr->e_machine == EM_MIPS) {
1892 unsigned int r_typ;
1893 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1894 r_sym = TO_NATIVE(r_sym);
1895 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1896 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1897 } else {
1898 r.r_info = TO_NATIVE(rel->r_info);
1899 r_sym = ELF_R_SYM(r.r_info);
1900 }
1901#else
1902 r.r_info = TO_NATIVE(rel->r_info);
1903 r_sym = ELF_R_SYM(r.r_info);
1904#endif
1905 r.r_addend = 0;
1906 switch (elf->hdr->e_machine) {
1907 case EM_386:
1908 if (addend_386_rel(elf, sechdr, &r))
1909 continue;
1910 break;
1911 case EM_ARM:
1912 if (addend_arm_rel(elf, sechdr, &r))
1913 continue;
1914 break;
1915 case EM_MIPS:
1916 if (addend_mips_rel(elf, sechdr, &r))
1917 continue;
1918 break;
1919 }
1920 sym = elf->symtab_start + r_sym;
1921 /* Skip special sections */
1922 if (is_shndx_special(sym->st_shndx))
1923 continue;
1924 if (is_second_extable_reloc(start, rel, fromsec))
1925 find_extable_entry_size(fromsec, &r);
1926 check_section_mismatch(modname, elf, &r, sym, fromsec);
1927 }
1928}
1929
1930/**
1931 * A module includes a number of sections that are discarded
1932 * either when loaded or when used as built-in.
1933 * For loaded modules all functions marked __init and all data
1934 * marked __initdata will be discarded when the module has been initialized.
1935 * Likewise for modules used built-in the sections marked __exit
1936 * are discarded because __exit marked function are supposed to be called
1937 * only when a module is unloaded which never happens for built-in modules.
1938 * The check_sec_ref() function traverses all relocation records
1939 * to find all references to a section that reference a section that will
1940 * be discarded and warns about it.
1941 **/
1942static void check_sec_ref(struct module *mod, const char *modname,
1943 struct elf_info *elf)
1944{
1945 int i;
1946 Elf_Shdr *sechdrs = elf->sechdrs;
1947
1948 /* Walk through all sections */
1949 for (i = 0; i < elf->num_sections; i++) {
1950 check_section(modname, elf, &elf->sechdrs[i]);
1951 /* We want to process only relocation sections and not .init */
1952 if (sechdrs[i].sh_type == SHT_RELA)
1953 section_rela(modname, elf, &elf->sechdrs[i]);
1954 else if (sechdrs[i].sh_type == SHT_REL)
1955 section_rel(modname, elf, &elf->sechdrs[i]);
1956 }
1957}
1958
1959static char *remove_dot(char *s)
1960{
1961 size_t n = strcspn(s, ".");
1962
1963 if (n && s[n]) {
1964 size_t m = strspn(s + n + 1, "0123456789");
1965 if (m && (s[n + m] == '.' || s[n + m] == 0))
1966 s[n] = 0;
1967
1968 /* strip trailing .lto */
1969 if (strends(s, ".lto"))
1970 s[strlen(s) - 4] = '\0';
1971 }
1972 return s;
1973}
1974
1975static void read_symbols(const char *modname)
1976{
1977 const char *symname;
1978 char *version;
1979 char *license;
1980 char *namespace;
1981 struct module *mod;
1982 struct elf_info info = { };
1983 Elf_Sym *sym;
1984
1985 if (!parse_elf(&info, modname))
1986 return;
1987
1988 {
1989 char *tmp;
1990
1991 /* strip trailing .o */
1992 tmp = NOFAIL(strdup(modname));
1993 tmp[strlen(tmp) - 2] = '\0';
1994 /* strip trailing .lto */
1995 if (strends(tmp, ".lto"))
1996 tmp[strlen(tmp) - 4] = '\0';
1997 mod = new_module(tmp);
1998 free(tmp);
1999 }
2000
2001 if (!mod->is_vmlinux) {
2002 license = get_modinfo(&info, "license");
2003 if (!license)
2004 error("missing MODULE_LICENSE() in %s\n", modname);
2005 while (license) {
2006 if (license_is_gpl_compatible(license))
2007 mod->gpl_compatible = 1;
2008 else {
2009 mod->gpl_compatible = 0;
2010 break;
2011 }
2012 license = get_next_modinfo(&info, "license", license);
2013 }
2014
2015 namespace = get_modinfo(&info, "import_ns");
2016 while (namespace) {
2017 add_namespace(&mod->imported_namespaces, namespace);
2018 namespace = get_next_modinfo(&info, "import_ns",
2019 namespace);
2020 }
2021 }
2022
2023 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2024 symname = remove_dot(info.strtab + sym->st_name);
2025
2026 handle_symbol(mod, &info, sym, symname);
2027 handle_moddevtable(mod, &info, sym, symname);
2028 }
2029
2030 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2031 symname = remove_dot(info.strtab + sym->st_name);
2032
2033 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
2034 if (strstarts(symname, "__kstrtabns_"))
2035 sym_update_namespace(symname + strlen("__kstrtabns_"),
2036 namespace_from_kstrtabns(&info,
2037 sym));
2038
2039 if (strstarts(symname, "__crc_"))
2040 handle_modversion(mod, &info, sym,
2041 symname + strlen("__crc_"));
2042 }
2043
2044 // check for static EXPORT_SYMBOL_* functions && global vars
2045 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2046 unsigned char bind = ELF_ST_BIND(sym->st_info);
2047
2048 if (bind == STB_GLOBAL || bind == STB_WEAK) {
2049 struct symbol *s =
2050 find_symbol(remove_dot(info.strtab +
2051 sym->st_name));
2052
2053 if (s)
2054 s->is_static = 0;
2055 }
2056 }
2057
2058 check_sec_ref(mod, modname, &info);
2059
2060 if (!mod->is_vmlinux) {
2061 version = get_modinfo(&info, "version");
2062 if (version || all_versions)
2063 get_src_version(modname, mod->srcversion,
2064 sizeof(mod->srcversion) - 1);
2065 }
2066
2067 parse_elf_finish(&info);
2068
2069 /* Our trick to get versioning for module struct etc. - it's
2070 * never passed as an argument to an exported function, so
2071 * the automatic versioning doesn't pick it up, but it's really
2072 * important anyhow */
2073 if (modversions)
2074 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2075}
2076
2077static void read_symbols_from_files(const char *filename)
2078{
2079 FILE *in = stdin;
2080 char fname[PATH_MAX];
2081
2082 if (strcmp(filename, "-") != 0) {
2083 in = fopen(filename, "r");
2084 if (!in)
2085 fatal("Can't open filenames file %s: %m", filename);
2086 }
2087
2088 while (fgets(fname, PATH_MAX, in) != NULL) {
2089 if (strends(fname, "\n"))
2090 fname[strlen(fname)-1] = '\0';
2091 read_symbols(fname);
2092 }
2093
2094 if (in != stdin)
2095 fclose(in);
2096}
2097
2098#define SZ 500
2099
2100/* We first write the generated file into memory using the
2101 * following helper, then compare to the file on disk and
2102 * only update the later if anything changed */
2103
2104void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2105 const char *fmt, ...)
2106{
2107 char tmp[SZ];
2108 int len;
2109 va_list ap;
2110
2111 va_start(ap, fmt);
2112 len = vsnprintf(tmp, SZ, fmt, ap);
2113 buf_write(buf, tmp, len);
2114 va_end(ap);
2115}
2116
2117void buf_write(struct buffer *buf, const char *s, int len)
2118{
2119 if (buf->size - buf->pos < len) {
2120 buf->size += len + SZ;
2121 buf->p = NOFAIL(realloc(buf->p, buf->size));
2122 }
2123 strncpy(buf->p + buf->pos, s, len);
2124 buf->pos += len;
2125}
2126
2127static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2128{
2129 switch (exp) {
2130 case export_gpl:
2131 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
2132 m, s);
2133 break;
2134 case export_plain:
2135 case export_unknown:
2136 /* ignore */
2137 break;
2138 }
2139}
2140
2141static void check_exports(struct module *mod)
2142{
2143 struct symbol *s, *exp;
2144
2145 for (s = mod->unres; s; s = s->next) {
2146 const char *basename;
2147 exp = find_symbol(s->name);
2148 if (!exp || exp->module == mod) {
2149 if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
2150 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
2151 "\"%s\" [%s.ko] undefined!\n",
2152 s->name, mod->name);
2153 continue;
2154 }
2155 basename = strrchr(mod->name, '/');
2156 if (basename)
2157 basename++;
2158 else
2159 basename = mod->name;
2160
2161 if (exp->namespace &&
2162 !module_imports_namespace(mod, exp->namespace)) {
2163 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
2164 "module %s uses symbol %s from namespace %s, but does not import it.\n",
2165 basename, exp->name, exp->namespace);
2166 add_namespace(&mod->missing_namespaces, exp->namespace);
2167 }
2168
2169 if (!mod->gpl_compatible)
2170 check_for_gpl_usage(exp->export, basename, exp->name);
2171 }
2172}
2173
2174static void check_modname_len(struct module *mod)
2175{
2176 const char *mod_name;
2177
2178 mod_name = strrchr(mod->name, '/');
2179 if (mod_name == NULL)
2180 mod_name = mod->name;
2181 else
2182 mod_name++;
2183 if (strlen(mod_name) >= MODULE_NAME_LEN)
2184 error("module name is too long [%s.ko]\n", mod->name);
2185}
2186
2187/**
2188 * Header for the generated file
2189 **/
2190static void add_header(struct buffer *b, struct module *mod)
2191{
2192 buf_printf(b, "#include <linux/module.h>\n");
2193 /*
2194 * Include build-salt.h after module.h in order to
2195 * inherit the definitions.
2196 */
2197 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
2198 buf_printf(b, "#include <linux/build-salt.h>\n");
2199 buf_printf(b, "#include <linux/elfnote-lto.h>\n");
2200 buf_printf(b, "#include <linux/vermagic.h>\n");
2201 buf_printf(b, "#include <linux/compiler.h>\n");
2202 buf_printf(b, "\n");
2203 buf_printf(b, "BUILD_SALT;\n");
2204 buf_printf(b, "BUILD_LTO_INFO;\n");
2205 buf_printf(b, "\n");
2206 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2207 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2208 buf_printf(b, "\n");
2209 buf_printf(b, "__visible struct module __this_module\n");
2210 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
2211 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2212 if (mod->has_init)
2213 buf_printf(b, "\t.init = init_module,\n");
2214 if (mod->has_cleanup)
2215 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2216 "\t.exit = cleanup_module,\n"
2217 "#endif\n");
2218 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2219 buf_printf(b, "};\n");
2220}
2221
2222static void add_intree_flag(struct buffer *b, int is_intree)
2223{
2224 if (is_intree)
2225 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2226}
2227
2228/* Cannot check for assembler */
2229static void add_retpoline(struct buffer *b)
2230{
2231 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2232 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2233 buf_printf(b, "#endif\n");
2234}
2235
2236static void add_staging_flag(struct buffer *b, const char *name)
2237{
2238 if (strstarts(name, "drivers/staging"))
2239 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2240}
2241
2242/**
2243 * Record CRCs for unresolved symbols
2244 **/
2245static void add_versions(struct buffer *b, struct module *mod)
2246{
2247 struct symbol *s, *exp;
2248
2249 for (s = mod->unres; s; s = s->next) {
2250 exp = find_symbol(s->name);
2251 if (!exp || exp->module == mod)
2252 continue;
2253 s->module = exp->module;
2254 s->crc_valid = exp->crc_valid;
2255 s->crc = exp->crc;
2256 }
2257
2258 if (!modversions)
2259 return;
2260
2261 buf_printf(b, "\n");
2262 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2263 buf_printf(b, "__used __section(\"__versions\") = {\n");
2264
2265 for (s = mod->unres; s; s = s->next) {
2266 if (!s->module)
2267 continue;
2268 if (!s->crc_valid) {
2269 warn("\"%s\" [%s.ko] has no CRC!\n",
2270 s->name, mod->name);
2271 continue;
2272 }
2273 if (strlen(s->name) >= MODULE_NAME_LEN) {
2274 error("too long symbol \"%s\" [%s.ko]\n",
2275 s->name, mod->name);
2276 break;
2277 }
2278 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2279 s->crc, s->name);
2280 }
2281
2282 buf_printf(b, "};\n");
2283}
2284
2285static void add_depends(struct buffer *b, struct module *mod)
2286{
2287 struct symbol *s;
2288 int first = 1;
2289
2290 /* Clear ->seen flag of modules that own symbols needed by this. */
2291 for (s = mod->unres; s; s = s->next)
2292 if (s->module)
2293 s->module->seen = s->module->is_vmlinux;
2294
2295 buf_printf(b, "\n");
2296 buf_printf(b, "MODULE_INFO(depends, \"");
2297 for (s = mod->unres; s; s = s->next) {
2298 const char *p;
2299 if (!s->module)
2300 continue;
2301
2302 if (s->module->seen)
2303 continue;
2304
2305 s->module->seen = 1;
2306 p = strrchr(s->module->name, '/');
2307 if (p)
2308 p++;
2309 else
2310 p = s->module->name;
2311 buf_printf(b, "%s%s", first ? "" : ",", p);
2312 first = 0;
2313 }
2314 buf_printf(b, "\");\n");
2315}
2316
2317static void add_srcversion(struct buffer *b, struct module *mod)
2318{
2319 if (mod->srcversion[0]) {
2320 buf_printf(b, "\n");
2321 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2322 mod->srcversion);
2323 }
2324}
2325
2326static void write_buf(struct buffer *b, const char *fname)
2327{
2328 FILE *file;
2329
2330 file = fopen(fname, "w");
2331 if (!file) {
2332 perror(fname);
2333 exit(1);
2334 }
2335 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2336 perror(fname);
2337 exit(1);
2338 }
2339 if (fclose(file) != 0) {
2340 perror(fname);
2341 exit(1);
2342 }
2343}
2344
2345static void write_if_changed(struct buffer *b, const char *fname)
2346{
2347 char *tmp;
2348 FILE *file;
2349 struct stat st;
2350
2351 file = fopen(fname, "r");
2352 if (!file)
2353 goto write;
2354
2355 if (fstat(fileno(file), &st) < 0)
2356 goto close_write;
2357
2358 if (st.st_size != b->pos)
2359 goto close_write;
2360
2361 tmp = NOFAIL(malloc(b->pos));
2362 if (fread(tmp, 1, b->pos, file) != b->pos)
2363 goto free_write;
2364
2365 if (memcmp(tmp, b->p, b->pos) != 0)
2366 goto free_write;
2367
2368 free(tmp);
2369 fclose(file);
2370 return;
2371
2372 free_write:
2373 free(tmp);
2374 close_write:
2375 fclose(file);
2376 write:
2377 write_buf(b, fname);
2378}
2379
2380/* parse Module.symvers file. line format:
2381 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2382 **/
2383static void read_dump(const char *fname)
2384{
2385 char *buf, *pos, *line;
2386
2387 buf = read_text_file(fname);
2388 if (!buf)
2389 /* No symbol versions, silently ignore */
2390 return;
2391
2392 pos = buf;
2393
2394 while ((line = get_line(&pos))) {
2395 char *symname, *namespace, *modname, *d, *export;
2396 unsigned int crc;
2397 struct module *mod;
2398 struct symbol *s;
2399
2400 if (!(symname = strchr(line, '\t')))
2401 goto fail;
2402 *symname++ = '\0';
2403 if (!(modname = strchr(symname, '\t')))
2404 goto fail;
2405 *modname++ = '\0';
2406 if (!(export = strchr(modname, '\t')))
2407 goto fail;
2408 *export++ = '\0';
2409 if (!(namespace = strchr(export, '\t')))
2410 goto fail;
2411 *namespace++ = '\0';
2412
2413 crc = strtoul(line, &d, 16);
2414 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2415 goto fail;
2416 mod = find_module(modname);
2417 if (!mod) {
2418 mod = new_module(modname);
2419 mod->from_dump = 1;
2420 }
2421 s = sym_add_exported(symname, mod, export_no(export));
2422 s->is_static = 0;
2423 sym_set_crc(symname, crc);
2424 sym_update_namespace(symname, namespace);
2425 }
2426 free(buf);
2427 return;
2428fail:
2429 free(buf);
2430 fatal("parse error in symbol dump file\n");
2431}
2432
2433static void write_dump(const char *fname)
2434{
2435 struct buffer buf = { };
2436 struct symbol *symbol;
2437 const char *namespace;
2438 int n;
2439
2440 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2441 symbol = symbolhash[n];
2442 while (symbol) {
2443 if (!symbol->module->from_dump) {
2444 namespace = symbol->namespace;
2445 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
2446 symbol->crc, symbol->name,
2447 symbol->module->name,
2448 export_str(symbol->export),
2449 namespace ? namespace : "");
2450 }
2451 symbol = symbol->next;
2452 }
2453 }
2454 write_buf(&buf, fname);
2455 free(buf.p);
2456}
2457
2458static void write_namespace_deps_files(const char *fname)
2459{
2460 struct module *mod;
2461 struct namespace_list *ns;
2462 struct buffer ns_deps_buf = {};
2463
2464 for (mod = modules; mod; mod = mod->next) {
2465
2466 if (mod->from_dump || !mod->missing_namespaces)
2467 continue;
2468
2469 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2470
2471 for (ns = mod->missing_namespaces; ns; ns = ns->next)
2472 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2473
2474 buf_printf(&ns_deps_buf, "\n");
2475 }
2476
2477 write_if_changed(&ns_deps_buf, fname);
2478 free(ns_deps_buf.p);
2479}
2480
2481struct dump_list {
2482 struct dump_list *next;
2483 const char *file;
2484};
2485
2486int main(int argc, char **argv)
2487{
2488 struct module *mod;
2489 struct buffer buf = { };
2490 char *missing_namespace_deps = NULL;
2491 char *dump_write = NULL, *files_source = NULL;
2492 int opt;
2493 int n;
2494 struct dump_list *dump_read_start = NULL;
2495 struct dump_list **dump_read_iter = &dump_read_start;
2496
2497 while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) {
2498 switch (opt) {
2499 case 'e':
2500 external_module = 1;
2501 break;
2502 case 'i':
2503 *dump_read_iter =
2504 NOFAIL(calloc(1, sizeof(**dump_read_iter)));
2505 (*dump_read_iter)->file = optarg;
2506 dump_read_iter = &(*dump_read_iter)->next;
2507 break;
2508 case 'm':
2509 modversions = 1;
2510 break;
2511 case 'n':
2512 ignore_missing_files = 1;
2513 break;
2514 case 'o':
2515 dump_write = optarg;
2516 break;
2517 case 'a':
2518 all_versions = 1;
2519 break;
2520 case 'T':
2521 files_source = optarg;
2522 break;
2523 case 'w':
2524 warn_unresolved = 1;
2525 break;
2526 case 'E':
2527 sec_mismatch_warn_only = false;
2528 break;
2529 case 'N':
2530 allow_missing_ns_imports = 1;
2531 break;
2532 case 'd':
2533 missing_namespace_deps = optarg;
2534 break;
2535 default:
2536 exit(1);
2537 }
2538 }
2539
2540 while (dump_read_start) {
2541 struct dump_list *tmp;
2542
2543 read_dump(dump_read_start->file);
2544 tmp = dump_read_start->next;
2545 free(dump_read_start);
2546 dump_read_start = tmp;
2547 }
2548
2549 while (optind < argc)
2550 read_symbols(argv[optind++]);
2551
2552 if (files_source)
2553 read_symbols_from_files(files_source);
2554
2555 for (mod = modules; mod; mod = mod->next) {
2556 char fname[PATH_MAX];
2557
2558 if (mod->is_vmlinux || mod->from_dump)
2559 continue;
2560
2561 buf.pos = 0;
2562
2563 check_modname_len(mod);
2564 check_exports(mod);
2565
2566 add_header(&buf, mod);
2567 add_intree_flag(&buf, !external_module);
2568 add_retpoline(&buf);
2569 add_staging_flag(&buf, mod->name);
2570 add_versions(&buf, mod);
2571 add_depends(&buf, mod);
2572 add_moddevtable(&buf, mod);
2573 add_srcversion(&buf, mod);
2574
2575 sprintf(fname, "%s.mod.c", mod->name);
2576 write_if_changed(&buf, fname);
2577 }
2578
2579 if (missing_namespace_deps)
2580 write_namespace_deps_files(missing_namespace_deps);
2581
2582 if (dump_write)
2583 write_dump(dump_write);
2584 if (sec_mismatch_count && !sec_mismatch_warn_only)
2585 error("Section mismatches detected.\n"
2586 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2587 for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
2588 struct symbol *s;
2589
2590 for (s = symbolhash[n]; s; s = s->next) {
2591 if (s->is_static)
2592 error("\"%s\" [%s] is a static %s\n",
2593 s->name, s->module->name,
2594 export_str(s->export));
2595 }
2596 }
2597
2598 if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2599 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2600 nr_unresolved - MAX_UNRESOLVED_REPORTS);
2601
2602 free(buf.p);
2603
2604 return error_occurred ? 1 : 0;
2605}
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 <fnmatch.h>
17#include <stdio.h>
18#include <ctype.h>
19#include <string.h>
20#include <limits.h>
21#include <stdbool.h>
22#include <errno.h>
23#include "modpost.h"
24#include "../../include/linux/license.h"
25
26static bool module_enabled;
27/* Are we using CONFIG_MODVERSIONS? */
28static bool modversions;
29/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
30static bool all_versions;
31/* If we are modposting external module set to 1 */
32static bool external_module;
33/* Only warn about unresolved symbols */
34static bool warn_unresolved;
35
36static int sec_mismatch_count;
37static bool sec_mismatch_warn_only = true;
38/* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
39static bool trim_unused_exports;
40
41/* ignore missing files */
42static bool ignore_missing_files;
43/* If set to 1, only warn (instead of error) about missing ns imports */
44static bool allow_missing_ns_imports;
45
46static bool error_occurred;
47
48static bool extra_warn;
49
50/*
51 * Cut off the warnings when there are too many. This typically occurs when
52 * vmlinux is missing. ('make modules' without building vmlinux.)
53 */
54#define MAX_UNRESOLVED_REPORTS 10
55static unsigned int nr_unresolved;
56
57/* In kernel, this size is defined in linux/module.h;
58 * here we use Elf_Addr instead of long for covering cross-compile
59 */
60
61#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
62
63void modpost_log(enum loglevel loglevel, const char *fmt, ...)
64{
65 va_list arglist;
66
67 switch (loglevel) {
68 case LOG_WARN:
69 fprintf(stderr, "WARNING: ");
70 break;
71 case LOG_ERROR:
72 fprintf(stderr, "ERROR: ");
73 error_occurred = true;
74 break;
75 default: /* invalid loglevel, ignore */
76 break;
77 }
78
79 fprintf(stderr, "modpost: ");
80
81 va_start(arglist, fmt);
82 vfprintf(stderr, fmt, arglist);
83 va_end(arglist);
84}
85
86static inline bool strends(const char *str, const char *postfix)
87{
88 if (strlen(str) < strlen(postfix))
89 return false;
90
91 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
92}
93
94void *do_nofail(void *ptr, const char *expr)
95{
96 if (!ptr)
97 fatal("Memory allocation failure: %s.\n", expr);
98
99 return ptr;
100}
101
102char *read_text_file(const char *filename)
103{
104 struct stat st;
105 size_t nbytes;
106 int fd;
107 char *buf;
108
109 fd = open(filename, O_RDONLY);
110 if (fd < 0) {
111 perror(filename);
112 exit(1);
113 }
114
115 if (fstat(fd, &st) < 0) {
116 perror(filename);
117 exit(1);
118 }
119
120 buf = NOFAIL(malloc(st.st_size + 1));
121
122 nbytes = st.st_size;
123
124 while (nbytes) {
125 ssize_t bytes_read;
126
127 bytes_read = read(fd, buf, nbytes);
128 if (bytes_read < 0) {
129 perror(filename);
130 exit(1);
131 }
132
133 nbytes -= bytes_read;
134 }
135 buf[st.st_size] = '\0';
136
137 close(fd);
138
139 return buf;
140}
141
142char *get_line(char **stringp)
143{
144 char *orig = *stringp, *next;
145
146 /* do not return the unwanted extra line at EOF */
147 if (!orig || *orig == '\0')
148 return NULL;
149
150 /* don't use strsep here, it is not available everywhere */
151 next = strchr(orig, '\n');
152 if (next)
153 *next++ = '\0';
154
155 *stringp = next;
156
157 return orig;
158}
159
160/* A list of all modules we processed */
161LIST_HEAD(modules);
162
163static struct module *find_module(const char *modname)
164{
165 struct module *mod;
166
167 list_for_each_entry(mod, &modules, list) {
168 if (strcmp(mod->name, modname) == 0)
169 return mod;
170 }
171 return NULL;
172}
173
174static struct module *new_module(const char *name, size_t namelen)
175{
176 struct module *mod;
177
178 mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
179 memset(mod, 0, sizeof(*mod));
180
181 INIT_LIST_HEAD(&mod->exported_symbols);
182 INIT_LIST_HEAD(&mod->unresolved_symbols);
183 INIT_LIST_HEAD(&mod->missing_namespaces);
184 INIT_LIST_HEAD(&mod->imported_namespaces);
185
186 memcpy(mod->name, name, namelen);
187 mod->name[namelen] = '\0';
188 mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
189
190 /*
191 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
192 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
193 * modpost will exit wiht error anyway.
194 */
195 mod->is_gpl_compatible = true;
196
197 list_add_tail(&mod->list, &modules);
198
199 return mod;
200}
201
202/* A hash of all exported symbols,
203 * struct symbol is also used for lists of unresolved symbols */
204
205#define SYMBOL_HASH_SIZE 1024
206
207struct symbol {
208 struct symbol *next;
209 struct list_head list; /* link to module::exported_symbols or module::unresolved_symbols */
210 struct module *module;
211 char *namespace;
212 unsigned int crc;
213 bool crc_valid;
214 bool weak;
215 bool is_func;
216 bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */
217 bool used; /* there exists a user of this symbol */
218 char name[];
219};
220
221static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
222
223/* This is based on the hash algorithm from gdbm, via tdb */
224static inline unsigned int tdb_hash(const char *name)
225{
226 unsigned value; /* Used to compute the hash value. */
227 unsigned i; /* Used to cycle through random values. */
228
229 /* Set the initial value from the key size. */
230 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
231 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
232
233 return (1103515243 * value + 12345);
234}
235
236/**
237 * Allocate a new symbols for use in the hash of exported symbols or
238 * the list of unresolved symbols per module
239 **/
240static struct symbol *alloc_symbol(const char *name)
241{
242 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
243
244 memset(s, 0, sizeof(*s));
245 strcpy(s->name, name);
246
247 return s;
248}
249
250/* For the hash of exported symbols */
251static void hash_add_symbol(struct symbol *sym)
252{
253 unsigned int hash;
254
255 hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE;
256 sym->next = symbolhash[hash];
257 symbolhash[hash] = sym;
258}
259
260static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
261{
262 struct symbol *sym;
263
264 sym = alloc_symbol(name);
265 sym->weak = weak;
266
267 list_add_tail(&sym->list, &mod->unresolved_symbols);
268}
269
270static struct symbol *sym_find_with_module(const char *name, struct module *mod)
271{
272 struct symbol *s;
273
274 /* For our purposes, .foo matches foo. PPC64 needs this. */
275 if (name[0] == '.')
276 name++;
277
278 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
279 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
280 return s;
281 }
282 return NULL;
283}
284
285static struct symbol *find_symbol(const char *name)
286{
287 return sym_find_with_module(name, NULL);
288}
289
290struct namespace_list {
291 struct list_head list;
292 char namespace[];
293};
294
295static bool contains_namespace(struct list_head *head, const char *namespace)
296{
297 struct namespace_list *list;
298
299 /*
300 * The default namespace is null string "", which is always implicitly
301 * contained.
302 */
303 if (!namespace[0])
304 return true;
305
306 list_for_each_entry(list, head, list) {
307 if (!strcmp(list->namespace, namespace))
308 return true;
309 }
310
311 return false;
312}
313
314static void add_namespace(struct list_head *head, const char *namespace)
315{
316 struct namespace_list *ns_entry;
317
318 if (!contains_namespace(head, namespace)) {
319 ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
320 strlen(namespace) + 1));
321 strcpy(ns_entry->namespace, namespace);
322 list_add_tail(&ns_entry->list, head);
323 }
324}
325
326static void *sym_get_data_by_offset(const struct elf_info *info,
327 unsigned int secindex, unsigned long offset)
328{
329 Elf_Shdr *sechdr = &info->sechdrs[secindex];
330
331 return (void *)info->hdr + sechdr->sh_offset + offset;
332}
333
334void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
335{
336 return sym_get_data_by_offset(info, get_secindex(info, sym),
337 sym->st_value);
338}
339
340static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
341{
342 return sym_get_data_by_offset(info, info->secindex_strings,
343 sechdr->sh_name);
344}
345
346static const char *sec_name(const struct elf_info *info, unsigned int secindex)
347{
348 /*
349 * If sym->st_shndx is a special section index, there is no
350 * corresponding section header.
351 * Return "" if the index is out of range of info->sechdrs[] array.
352 */
353 if (secindex >= info->num_sections)
354 return "";
355
356 return sech_name(info, &info->sechdrs[secindex]);
357}
358
359#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
360
361static struct symbol *sym_add_exported(const char *name, struct module *mod,
362 bool gpl_only, const char *namespace)
363{
364 struct symbol *s = find_symbol(name);
365
366 if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
367 error("%s: '%s' exported twice. Previous export was in %s%s\n",
368 mod->name, name, s->module->name,
369 s->module->is_vmlinux ? "" : ".ko");
370 }
371
372 s = alloc_symbol(name);
373 s->module = mod;
374 s->is_gpl_only = gpl_only;
375 s->namespace = NOFAIL(strdup(namespace));
376 list_add_tail(&s->list, &mod->exported_symbols);
377 hash_add_symbol(s);
378
379 return s;
380}
381
382static void sym_set_crc(struct symbol *sym, unsigned int crc)
383{
384 sym->crc = crc;
385 sym->crc_valid = true;
386}
387
388static void *grab_file(const char *filename, size_t *size)
389{
390 struct stat st;
391 void *map = MAP_FAILED;
392 int fd;
393
394 fd = open(filename, O_RDONLY);
395 if (fd < 0)
396 return NULL;
397 if (fstat(fd, &st))
398 goto failed;
399
400 *size = st.st_size;
401 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
402
403failed:
404 close(fd);
405 if (map == MAP_FAILED)
406 return NULL;
407 return map;
408}
409
410static void release_file(void *file, size_t size)
411{
412 munmap(file, size);
413}
414
415static int parse_elf(struct elf_info *info, const char *filename)
416{
417 unsigned int i;
418 Elf_Ehdr *hdr;
419 Elf_Shdr *sechdrs;
420 Elf_Sym *sym;
421 const char *secstrings;
422 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
423
424 hdr = grab_file(filename, &info->size);
425 if (!hdr) {
426 if (ignore_missing_files) {
427 fprintf(stderr, "%s: %s (ignored)\n", filename,
428 strerror(errno));
429 return 0;
430 }
431 perror(filename);
432 exit(1);
433 }
434 info->hdr = hdr;
435 if (info->size < sizeof(*hdr)) {
436 /* file too small, assume this is an empty .o file */
437 return 0;
438 }
439 /* Is this a valid ELF file? */
440 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
441 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
442 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
443 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
444 /* Not an ELF file - silently ignore it */
445 return 0;
446 }
447 /* Fix endianness in ELF header */
448 hdr->e_type = TO_NATIVE(hdr->e_type);
449 hdr->e_machine = TO_NATIVE(hdr->e_machine);
450 hdr->e_version = TO_NATIVE(hdr->e_version);
451 hdr->e_entry = TO_NATIVE(hdr->e_entry);
452 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
453 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
454 hdr->e_flags = TO_NATIVE(hdr->e_flags);
455 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
456 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
457 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
458 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
459 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
460 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
461 sechdrs = (void *)hdr + hdr->e_shoff;
462 info->sechdrs = sechdrs;
463
464 /* modpost only works for relocatable objects */
465 if (hdr->e_type != ET_REL)
466 fatal("%s: not relocatable object.", filename);
467
468 /* Check if file offset is correct */
469 if (hdr->e_shoff > info->size)
470 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
471 (unsigned long)hdr->e_shoff, filename, info->size);
472
473 if (hdr->e_shnum == SHN_UNDEF) {
474 /*
475 * There are more than 64k sections,
476 * read count from .sh_size.
477 */
478 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
479 }
480 else {
481 info->num_sections = hdr->e_shnum;
482 }
483 if (hdr->e_shstrndx == SHN_XINDEX) {
484 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
485 }
486 else {
487 info->secindex_strings = hdr->e_shstrndx;
488 }
489
490 /* Fix endianness in section headers */
491 for (i = 0; i < info->num_sections; i++) {
492 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
493 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
494 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
495 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
496 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
497 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
498 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
499 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
500 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
501 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
502 }
503 /* Find symbol table. */
504 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
505 for (i = 1; i < info->num_sections; i++) {
506 const char *secname;
507 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
508
509 if (!nobits && sechdrs[i].sh_offset > info->size)
510 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
511 filename, (unsigned long)sechdrs[i].sh_offset,
512 sizeof(*hdr));
513
514 secname = secstrings + sechdrs[i].sh_name;
515 if (strcmp(secname, ".modinfo") == 0) {
516 if (nobits)
517 fatal("%s has NOBITS .modinfo\n", filename);
518 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
519 info->modinfo_len = sechdrs[i].sh_size;
520 } else if (!strcmp(secname, ".export_symbol")) {
521 info->export_symbol_secndx = i;
522 }
523
524 if (sechdrs[i].sh_type == SHT_SYMTAB) {
525 unsigned int sh_link_idx;
526 symtab_idx = i;
527 info->symtab_start = (void *)hdr +
528 sechdrs[i].sh_offset;
529 info->symtab_stop = (void *)hdr +
530 sechdrs[i].sh_offset + sechdrs[i].sh_size;
531 sh_link_idx = sechdrs[i].sh_link;
532 info->strtab = (void *)hdr +
533 sechdrs[sh_link_idx].sh_offset;
534 }
535
536 /* 32bit section no. table? ("more than 64k sections") */
537 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
538 symtab_shndx_idx = i;
539 info->symtab_shndx_start = (void *)hdr +
540 sechdrs[i].sh_offset;
541 info->symtab_shndx_stop = (void *)hdr +
542 sechdrs[i].sh_offset + sechdrs[i].sh_size;
543 }
544 }
545 if (!info->symtab_start)
546 fatal("%s has no symtab?\n", filename);
547
548 /* Fix endianness in symbols */
549 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
550 sym->st_shndx = TO_NATIVE(sym->st_shndx);
551 sym->st_name = TO_NATIVE(sym->st_name);
552 sym->st_value = TO_NATIVE(sym->st_value);
553 sym->st_size = TO_NATIVE(sym->st_size);
554 }
555
556 if (symtab_shndx_idx != ~0U) {
557 Elf32_Word *p;
558 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
559 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
560 filename, sechdrs[symtab_shndx_idx].sh_link,
561 symtab_idx);
562 /* Fix endianness */
563 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
564 p++)
565 *p = TO_NATIVE(*p);
566 }
567
568 symsearch_init(info);
569
570 return 1;
571}
572
573static void parse_elf_finish(struct elf_info *info)
574{
575 symsearch_finish(info);
576 release_file(info->hdr, info->size);
577}
578
579static int ignore_undef_symbol(struct elf_info *info, const char *symname)
580{
581 /* ignore __this_module, it will be resolved shortly */
582 if (strcmp(symname, "__this_module") == 0)
583 return 1;
584 /* ignore global offset table */
585 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
586 return 1;
587 if (info->hdr->e_machine == EM_PPC)
588 /* Special register function linked on all modules during final link of .ko */
589 if (strstarts(symname, "_restgpr_") ||
590 strstarts(symname, "_savegpr_") ||
591 strstarts(symname, "_rest32gpr_") ||
592 strstarts(symname, "_save32gpr_") ||
593 strstarts(symname, "_restvr_") ||
594 strstarts(symname, "_savevr_"))
595 return 1;
596 if (info->hdr->e_machine == EM_PPC64)
597 /* Special register function linked on all modules during final link of .ko */
598 if (strstarts(symname, "_restgpr0_") ||
599 strstarts(symname, "_savegpr0_") ||
600 strstarts(symname, "_restvr_") ||
601 strstarts(symname, "_savevr_") ||
602 strcmp(symname, ".TOC.") == 0)
603 return 1;
604
605 if (info->hdr->e_machine == EM_S390)
606 /* Expoline thunks are linked on all kernel modules during final link of .ko */
607 if (strstarts(symname, "__s390_indirect_jump_r"))
608 return 1;
609 /* Do not ignore this symbol */
610 return 0;
611}
612
613static void handle_symbol(struct module *mod, struct elf_info *info,
614 const Elf_Sym *sym, const char *symname)
615{
616 switch (sym->st_shndx) {
617 case SHN_COMMON:
618 if (strstarts(symname, "__gnu_lto_")) {
619 /* Should warn here, but modpost runs before the linker */
620 } else
621 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
622 break;
623 case SHN_UNDEF:
624 /* undefined symbol */
625 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
626 ELF_ST_BIND(sym->st_info) != STB_WEAK)
627 break;
628 if (ignore_undef_symbol(info, symname))
629 break;
630 if (info->hdr->e_machine == EM_SPARC ||
631 info->hdr->e_machine == EM_SPARCV9) {
632 /* Ignore register directives. */
633 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
634 break;
635 if (symname[0] == '.') {
636 char *munged = NOFAIL(strdup(symname));
637 munged[0] = '_';
638 munged[1] = toupper(munged[1]);
639 symname = munged;
640 }
641 }
642
643 sym_add_unresolved(symname, mod,
644 ELF_ST_BIND(sym->st_info) == STB_WEAK);
645 break;
646 default:
647 if (strcmp(symname, "init_module") == 0)
648 mod->has_init = true;
649 if (strcmp(symname, "cleanup_module") == 0)
650 mod->has_cleanup = true;
651 break;
652 }
653}
654
655/**
656 * Parse tag=value strings from .modinfo section
657 **/
658static char *next_string(char *string, unsigned long *secsize)
659{
660 /* Skip non-zero chars */
661 while (string[0]) {
662 string++;
663 if ((*secsize)-- <= 1)
664 return NULL;
665 }
666
667 /* Skip any zero padding. */
668 while (!string[0]) {
669 string++;
670 if ((*secsize)-- <= 1)
671 return NULL;
672 }
673 return string;
674}
675
676static char *get_next_modinfo(struct elf_info *info, const char *tag,
677 char *prev)
678{
679 char *p;
680 unsigned int taglen = strlen(tag);
681 char *modinfo = info->modinfo;
682 unsigned long size = info->modinfo_len;
683
684 if (prev) {
685 size -= prev - modinfo;
686 modinfo = next_string(prev, &size);
687 }
688
689 for (p = modinfo; p; p = next_string(p, &size)) {
690 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
691 return p + taglen + 1;
692 }
693 return NULL;
694}
695
696static char *get_modinfo(struct elf_info *info, const char *tag)
697
698{
699 return get_next_modinfo(info, tag, NULL);
700}
701
702static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
703{
704 if (sym)
705 return elf->strtab + sym->st_name;
706 else
707 return "(unknown)";
708}
709
710/*
711 * Check whether the 'string' argument matches one of the 'patterns',
712 * an array of shell wildcard patterns (glob).
713 *
714 * Return true is there is a match.
715 */
716static bool match(const char *string, const char *const patterns[])
717{
718 const char *pattern;
719
720 while ((pattern = *patterns++)) {
721 if (!fnmatch(pattern, string, 0))
722 return true;
723 }
724
725 return false;
726}
727
728/* useful to pass patterns to match() directly */
729#define PATTERNS(...) \
730 ({ \
731 static const char *const patterns[] = {__VA_ARGS__, NULL}; \
732 patterns; \
733 })
734
735/* sections that we do not want to do full section mismatch check on */
736static const char *const section_white_list[] =
737{
738 ".comment*",
739 ".debug*",
740 ".zdebug*", /* Compressed debug sections. */
741 ".GCC.command.line", /* record-gcc-switches */
742 ".mdebug*", /* alpha, score, mips etc. */
743 ".pdr", /* alpha, score, mips etc. */
744 ".stab*",
745 ".note*",
746 ".got*",
747 ".toc*",
748 ".xt.prop", /* xtensa */
749 ".xt.lit", /* xtensa */
750 ".arcextmap*", /* arc */
751 ".gnu.linkonce.arcext*", /* arc : modules */
752 ".cmem*", /* EZchip */
753 ".fmt_slot*", /* EZchip */
754 ".gnu.lto*",
755 ".discard.*",
756 ".llvm.call-graph-profile", /* call graph */
757 NULL
758};
759
760/*
761 * This is used to find sections missing the SHF_ALLOC flag.
762 * The cause of this is often a section specified in assembler
763 * without "ax" / "aw".
764 */
765static void check_section(const char *modname, struct elf_info *elf,
766 Elf_Shdr *sechdr)
767{
768 const char *sec = sech_name(elf, sechdr);
769
770 if (sechdr->sh_type == SHT_PROGBITS &&
771 !(sechdr->sh_flags & SHF_ALLOC) &&
772 !match(sec, section_white_list)) {
773 warn("%s (%s): unexpected non-allocatable section.\n"
774 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
775 "Note that for example <linux/init.h> contains\n"
776 "section definitions for use in .S files.\n\n",
777 modname, sec);
778 }
779}
780
781
782
783#define ALL_INIT_DATA_SECTIONS \
784 ".init.setup", ".init.rodata", ".meminit.rodata", \
785 ".init.data", ".meminit.data"
786
787#define ALL_PCI_INIT_SECTIONS \
788 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
789 ".pci_fixup_enable", ".pci_fixup_resume", \
790 ".pci_fixup_resume_early", ".pci_fixup_suspend"
791
792#define ALL_XXXINIT_SECTIONS ".meminit.*"
793
794#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
795#define ALL_EXIT_SECTIONS ".exit.*"
796
797#define DATA_SECTIONS ".data", ".data.rel"
798#define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
799 ".kprobes.text", ".cpuidle.text", ".noinstr.text", \
800 ".ltext", ".ltext.*"
801#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
802 ".fixup", ".entry.text", ".exception.text", \
803 ".coldtext", ".softirqentry.text"
804
805#define INIT_SECTIONS ".init.*"
806
807#define ALL_TEXT_SECTIONS ".init.text", ".meminit.text", ".exit.text", \
808 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
809
810enum mismatch {
811 TEXTDATA_TO_ANY_INIT_EXIT,
812 XXXINIT_TO_SOME_INIT,
813 ANY_INIT_TO_ANY_EXIT,
814 ANY_EXIT_TO_ANY_INIT,
815 EXTABLE_TO_NON_TEXT,
816};
817
818/**
819 * Describe how to match sections on different criteria:
820 *
821 * @fromsec: Array of sections to be matched.
822 *
823 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
824 * this array is forbidden (black-list). Can be empty.
825 *
826 * @good_tosec: Relocations applied to a section in @fromsec must be
827 * targeting sections in this array (white-list). Can be empty.
828 *
829 * @mismatch: Type of mismatch.
830 */
831struct sectioncheck {
832 const char *fromsec[20];
833 const char *bad_tosec[20];
834 const char *good_tosec[20];
835 enum mismatch mismatch;
836};
837
838static const struct sectioncheck sectioncheck[] = {
839/* Do not reference init/exit code/data from
840 * normal code and data
841 */
842{
843 .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
844 .bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
845 .mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
846},
847/* Do not reference init code/data from meminit code/data */
848{
849 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
850 .bad_tosec = { INIT_SECTIONS, NULL },
851 .mismatch = XXXINIT_TO_SOME_INIT,
852},
853/* Do not use exit code/data from init code */
854{
855 .fromsec = { ALL_INIT_SECTIONS, NULL },
856 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
857 .mismatch = ANY_INIT_TO_ANY_EXIT,
858},
859/* Do not use init code/data from exit code */
860{
861 .fromsec = { ALL_EXIT_SECTIONS, NULL },
862 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
863 .mismatch = ANY_EXIT_TO_ANY_INIT,
864},
865{
866 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
867 .bad_tosec = { INIT_SECTIONS, NULL },
868 .mismatch = ANY_INIT_TO_ANY_EXIT,
869},
870{
871 .fromsec = { "__ex_table", NULL },
872 /* If you're adding any new black-listed sections in here, consider
873 * adding a special 'printer' for them in scripts/check_extable.
874 */
875 .bad_tosec = { ".altinstr_replacement", NULL },
876 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
877 .mismatch = EXTABLE_TO_NON_TEXT,
878}
879};
880
881static const struct sectioncheck *section_mismatch(
882 const char *fromsec, const char *tosec)
883{
884 int i;
885
886 /*
887 * The target section could be the SHT_NUL section when we're
888 * handling relocations to un-resolved symbols, trying to match it
889 * doesn't make much sense and causes build failures on parisc
890 * architectures.
891 */
892 if (*tosec == '\0')
893 return NULL;
894
895 for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
896 const struct sectioncheck *check = §ioncheck[i];
897
898 if (match(fromsec, check->fromsec)) {
899 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
900 return check;
901 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
902 return check;
903 }
904 }
905 return NULL;
906}
907
908/**
909 * Whitelist to allow certain references to pass with no warning.
910 *
911 * Pattern 1:
912 * If a module parameter is declared __initdata and permissions=0
913 * then this is legal despite the warning generated.
914 * We cannot see value of permissions here, so just ignore
915 * this pattern.
916 * The pattern is identified by:
917 * tosec = .init.data
918 * fromsec = .data*
919 * atsym =__param*
920 *
921 * Pattern 1a:
922 * module_param_call() ops can refer to __init set function if permissions=0
923 * The pattern is identified by:
924 * tosec = .init.text
925 * fromsec = .data*
926 * atsym = __param_ops_*
927 *
928 * Pattern 3:
929 * Whitelist all references from .head.text to any init section
930 *
931 * Pattern 4:
932 * Some symbols belong to init section but still it is ok to reference
933 * these from non-init sections as these symbols don't have any memory
934 * allocated for them and symbol address and value are same. So even
935 * if init section is freed, its ok to reference those symbols.
936 * For ex. symbols marking the init section boundaries.
937 * This pattern is identified by
938 * refsymname = __init_begin, _sinittext, _einittext
939 *
940 * Pattern 5:
941 * GCC may optimize static inlines when fed constant arg(s) resulting
942 * in functions like cpumask_empty() -- generating an associated symbol
943 * cpumask_empty.constprop.3 that appears in the audit. If the const that
944 * is passed in comes from __init, like say nmi_ipi_mask, we get a
945 * meaningless section warning. May need to add isra symbols too...
946 * This pattern is identified by
947 * tosec = init section
948 * fromsec = text section
949 * refsymname = *.constprop.*
950 *
951 **/
952static int secref_whitelist(const char *fromsec, const char *fromsym,
953 const char *tosec, const char *tosym)
954{
955 /* Check for pattern 1 */
956 if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
957 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
958 strstarts(fromsym, "__param"))
959 return 0;
960
961 /* Check for pattern 1a */
962 if (strcmp(tosec, ".init.text") == 0 &&
963 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
964 strstarts(fromsym, "__param_ops_"))
965 return 0;
966
967 /* symbols in data sections that may refer to any init/exit sections */
968 if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
969 match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
970 match(fromsym, PATTERNS("*_ops", "*_probe", "*_console")))
971 return 0;
972
973 /*
974 * symbols in data sections must not refer to .exit.*, but there are
975 * quite a few offenders, so hide these unless for W=1 builds until
976 * these are fixed.
977 */
978 if (!extra_warn &&
979 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
980 match(tosec, PATTERNS(ALL_EXIT_SECTIONS)) &&
981 match(fromsym, PATTERNS("*driver")))
982 return 0;
983
984 /* Check for pattern 3 */
985 if (strstarts(fromsec, ".head.text") &&
986 match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
987 return 0;
988
989 /* Check for pattern 4 */
990 if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
991 return 0;
992
993 /* Check for pattern 5 */
994 if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
995 match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
996 match(fromsym, PATTERNS("*.constprop.*")))
997 return 0;
998
999 return 1;
1000}
1001
1002static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
1003 unsigned int secndx)
1004{
1005 return symsearch_find_nearest(elf, addr, secndx, false, ~0);
1006}
1007
1008static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
1009{
1010 Elf_Sym *new_sym;
1011
1012 /* If the supplied symbol has a valid name, return it */
1013 if (is_valid_name(elf, sym))
1014 return sym;
1015
1016 /*
1017 * Strive to find a better symbol name, but the resulting name may not
1018 * match the symbol referenced in the original code.
1019 */
1020 new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
1021 true, 20);
1022 return new_sym ? new_sym : sym;
1023}
1024
1025static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
1026{
1027 if (secndx >= elf->num_sections)
1028 return false;
1029
1030 return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
1031}
1032
1033static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1034 const struct sectioncheck* const mismatch,
1035 Elf_Sym *tsym,
1036 unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
1037 const char *tosec, Elf_Addr taddr)
1038{
1039 Elf_Sym *from;
1040 const char *tosym;
1041 const char *fromsym;
1042
1043 from = find_fromsym(elf, faddr, fsecndx);
1044 fromsym = sym_name(elf, from);
1045
1046 tsym = find_tosym(elf, taddr, tsym);
1047 tosym = sym_name(elf, tsym);
1048
1049 /* check whitelist - we may ignore it */
1050 if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1051 return;
1052
1053 sec_mismatch_count++;
1054
1055 warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
1056 modname, fromsym,
1057 (unsigned int)(faddr - (from ? from->st_value : 0)),
1058 fromsec, tosym, tosec);
1059
1060 if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1061 if (match(tosec, mismatch->bad_tosec))
1062 fatal("The relocation at %s+0x%lx references\n"
1063 "section \"%s\" which is black-listed.\n"
1064 "Something is seriously wrong and should be fixed.\n"
1065 "You might get more information about where this is\n"
1066 "coming from by using scripts/check_extable.sh %s\n",
1067 fromsec, (long)faddr, tosec, modname);
1068 else if (is_executable_section(elf, get_secindex(elf, tsym)))
1069 warn("The relocation at %s+0x%lx references\n"
1070 "section \"%s\" which is not in the list of\n"
1071 "authorized sections. If you're adding a new section\n"
1072 "and/or if this reference is valid, add \"%s\" to the\n"
1073 "list of authorized sections to jump to on fault.\n"
1074 "This can be achieved by adding \"%s\" to\n"
1075 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1076 fromsec, (long)faddr, tosec, tosec, tosec);
1077 else
1078 error("%s+0x%lx references non-executable section '%s'\n",
1079 fromsec, (long)faddr, tosec);
1080 }
1081}
1082
1083static void check_export_symbol(struct module *mod, struct elf_info *elf,
1084 Elf_Addr faddr, const char *secname,
1085 Elf_Sym *sym)
1086{
1087 static const char *prefix = "__export_symbol_";
1088 const char *label_name, *name, *data;
1089 Elf_Sym *label;
1090 struct symbol *s;
1091 bool is_gpl;
1092
1093 label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1094 label_name = sym_name(elf, label);
1095
1096 if (!strstarts(label_name, prefix)) {
1097 error("%s: .export_symbol section contains strange symbol '%s'\n",
1098 mod->name, label_name);
1099 return;
1100 }
1101
1102 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1103 ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1104 error("%s: local symbol '%s' was exported\n", mod->name,
1105 label_name + strlen(prefix));
1106 return;
1107 }
1108
1109 name = sym_name(elf, sym);
1110 if (strcmp(label_name + strlen(prefix), name)) {
1111 error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1112 mod->name, name);
1113 return;
1114 }
1115
1116 data = sym_get_data(elf, label); /* license */
1117 if (!strcmp(data, "GPL")) {
1118 is_gpl = true;
1119 } else if (!strcmp(data, "")) {
1120 is_gpl = false;
1121 } else {
1122 error("%s: unknown license '%s' was specified for '%s'\n",
1123 mod->name, data, name);
1124 return;
1125 }
1126
1127 data += strlen(data) + 1; /* namespace */
1128 s = sym_add_exported(name, mod, is_gpl, data);
1129
1130 /*
1131 * We need to be aware whether we are exporting a function or
1132 * a data on some architectures.
1133 */
1134 s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1135
1136 /*
1137 * For parisc64, symbols prefixed $$ from the library have the symbol type
1138 * STT_LOPROC. They should be handled as functions too.
1139 */
1140 if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
1141 elf->hdr->e_machine == EM_PARISC &&
1142 ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
1143 s->is_func = true;
1144
1145 if (match(secname, PATTERNS(ALL_INIT_SECTIONS)))
1146 warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1147 mod->name, name);
1148 else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS)))
1149 warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1150 mod->name, name);
1151}
1152
1153static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1154 Elf_Sym *sym,
1155 unsigned int fsecndx, const char *fromsec,
1156 Elf_Addr faddr, Elf_Addr taddr)
1157{
1158 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1159 const struct sectioncheck *mismatch;
1160
1161 if (module_enabled && elf->export_symbol_secndx == fsecndx) {
1162 check_export_symbol(mod, elf, faddr, tosec, sym);
1163 return;
1164 }
1165
1166 mismatch = section_mismatch(fromsec, tosec);
1167 if (!mismatch)
1168 return;
1169
1170 default_mismatch_handler(mod->name, elf, mismatch, sym,
1171 fsecndx, fromsec, faddr,
1172 tosec, taddr);
1173}
1174
1175static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
1176{
1177 switch (r_type) {
1178 case R_386_32:
1179 return TO_NATIVE(*location);
1180 case R_386_PC32:
1181 return TO_NATIVE(*location) + 4;
1182 }
1183
1184 return (Elf_Addr)(-1);
1185}
1186
1187#ifndef R_ARM_CALL
1188#define R_ARM_CALL 28
1189#endif
1190#ifndef R_ARM_JUMP24
1191#define R_ARM_JUMP24 29
1192#endif
1193
1194#ifndef R_ARM_THM_CALL
1195#define R_ARM_THM_CALL 10
1196#endif
1197#ifndef R_ARM_THM_JUMP24
1198#define R_ARM_THM_JUMP24 30
1199#endif
1200
1201#ifndef R_ARM_MOVW_ABS_NC
1202#define R_ARM_MOVW_ABS_NC 43
1203#endif
1204
1205#ifndef R_ARM_MOVT_ABS
1206#define R_ARM_MOVT_ABS 44
1207#endif
1208
1209#ifndef R_ARM_THM_MOVW_ABS_NC
1210#define R_ARM_THM_MOVW_ABS_NC 47
1211#endif
1212
1213#ifndef R_ARM_THM_MOVT_ABS
1214#define R_ARM_THM_MOVT_ABS 48
1215#endif
1216
1217#ifndef R_ARM_THM_JUMP19
1218#define R_ARM_THM_JUMP19 51
1219#endif
1220
1221static int32_t sign_extend32(int32_t value, int index)
1222{
1223 uint8_t shift = 31 - index;
1224
1225 return (int32_t)(value << shift) >> shift;
1226}
1227
1228static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
1229{
1230 uint32_t inst, upper, lower, sign, j1, j2;
1231 int32_t offset;
1232
1233 switch (r_type) {
1234 case R_ARM_ABS32:
1235 case R_ARM_REL32:
1236 inst = TO_NATIVE(*(uint32_t *)loc);
1237 return inst + sym->st_value;
1238 case R_ARM_MOVW_ABS_NC:
1239 case R_ARM_MOVT_ABS:
1240 inst = TO_NATIVE(*(uint32_t *)loc);
1241 offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1242 15);
1243 return offset + sym->st_value;
1244 case R_ARM_PC24:
1245 case R_ARM_CALL:
1246 case R_ARM_JUMP24:
1247 inst = TO_NATIVE(*(uint32_t *)loc);
1248 offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1249 return offset + sym->st_value + 8;
1250 case R_ARM_THM_MOVW_ABS_NC:
1251 case R_ARM_THM_MOVT_ABS:
1252 upper = TO_NATIVE(*(uint16_t *)loc);
1253 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1254 offset = sign_extend32(((upper & 0x000f) << 12) |
1255 ((upper & 0x0400) << 1) |
1256 ((lower & 0x7000) >> 4) |
1257 (lower & 0x00ff),
1258 15);
1259 return offset + sym->st_value;
1260 case R_ARM_THM_JUMP19:
1261 /*
1262 * Encoding T3:
1263 * S = upper[10]
1264 * imm6 = upper[5:0]
1265 * J1 = lower[13]
1266 * J2 = lower[11]
1267 * imm11 = lower[10:0]
1268 * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1269 */
1270 upper = TO_NATIVE(*(uint16_t *)loc);
1271 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1272
1273 sign = (upper >> 10) & 1;
1274 j1 = (lower >> 13) & 1;
1275 j2 = (lower >> 11) & 1;
1276 offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1277 ((upper & 0x03f) << 12) |
1278 ((lower & 0x07ff) << 1),
1279 20);
1280 return offset + sym->st_value + 4;
1281 case R_ARM_THM_CALL:
1282 case R_ARM_THM_JUMP24:
1283 /*
1284 * Encoding T4:
1285 * S = upper[10]
1286 * imm10 = upper[9:0]
1287 * J1 = lower[13]
1288 * J2 = lower[11]
1289 * imm11 = lower[10:0]
1290 * I1 = NOT(J1 XOR S)
1291 * I2 = NOT(J2 XOR S)
1292 * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1293 */
1294 upper = TO_NATIVE(*(uint16_t *)loc);
1295 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1296
1297 sign = (upper >> 10) & 1;
1298 j1 = (lower >> 13) & 1;
1299 j2 = (lower >> 11) & 1;
1300 offset = sign_extend32((sign << 24) |
1301 ((~(j1 ^ sign) & 1) << 23) |
1302 ((~(j2 ^ sign) & 1) << 22) |
1303 ((upper & 0x03ff) << 12) |
1304 ((lower & 0x07ff) << 1),
1305 24);
1306 return offset + sym->st_value + 4;
1307 }
1308
1309 return (Elf_Addr)(-1);
1310}
1311
1312static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
1313{
1314 uint32_t inst;
1315
1316 inst = TO_NATIVE(*location);
1317 switch (r_type) {
1318 case R_MIPS_LO16:
1319 return inst & 0xffff;
1320 case R_MIPS_26:
1321 return (inst & 0x03ffffff) << 2;
1322 case R_MIPS_32:
1323 return inst;
1324 }
1325 return (Elf_Addr)(-1);
1326}
1327
1328#ifndef EM_RISCV
1329#define EM_RISCV 243
1330#endif
1331
1332#ifndef R_RISCV_SUB32
1333#define R_RISCV_SUB32 39
1334#endif
1335
1336#ifndef EM_LOONGARCH
1337#define EM_LOONGARCH 258
1338#endif
1339
1340#ifndef R_LARCH_SUB32
1341#define R_LARCH_SUB32 55
1342#endif
1343
1344#ifndef R_LARCH_RELAX
1345#define R_LARCH_RELAX 100
1346#endif
1347
1348#ifndef R_LARCH_ALIGN
1349#define R_LARCH_ALIGN 102
1350#endif
1351
1352static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
1353 unsigned int *r_type, unsigned int *r_sym)
1354{
1355 typedef struct {
1356 Elf64_Word r_sym; /* Symbol index */
1357 unsigned char r_ssym; /* Special symbol for 2nd relocation */
1358 unsigned char r_type3; /* 3rd relocation type */
1359 unsigned char r_type2; /* 2nd relocation type */
1360 unsigned char r_type; /* 1st relocation type */
1361 } Elf64_Mips_R_Info;
1362
1363 bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
1364
1365 if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
1366 Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
1367
1368 *r_type = mips64_r_info->r_type;
1369 *r_sym = TO_NATIVE(mips64_r_info->r_sym);
1370 return;
1371 }
1372
1373 if (is_64bit)
1374 r_info = TO_NATIVE((Elf64_Xword)r_info);
1375 else
1376 r_info = TO_NATIVE((Elf32_Word)r_info);
1377
1378 *r_type = ELF_R_TYPE(r_info);
1379 *r_sym = ELF_R_SYM(r_info);
1380}
1381
1382static void section_rela(struct module *mod, struct elf_info *elf,
1383 unsigned int fsecndx, const char *fromsec,
1384 const Elf_Rela *start, const Elf_Rela *stop)
1385{
1386 const Elf_Rela *rela;
1387
1388 for (rela = start; rela < stop; rela++) {
1389 Elf_Sym *tsym;
1390 Elf_Addr taddr, r_offset;
1391 unsigned int r_type, r_sym;
1392
1393 r_offset = TO_NATIVE(rela->r_offset);
1394 get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
1395
1396 tsym = elf->symtab_start + r_sym;
1397 taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
1398
1399 switch (elf->hdr->e_machine) {
1400 case EM_RISCV:
1401 if (!strcmp("__ex_table", fromsec) &&
1402 r_type == R_RISCV_SUB32)
1403 continue;
1404 break;
1405 case EM_LOONGARCH:
1406 switch (r_type) {
1407 case R_LARCH_SUB32:
1408 if (!strcmp("__ex_table", fromsec))
1409 continue;
1410 break;
1411 case R_LARCH_RELAX:
1412 case R_LARCH_ALIGN:
1413 /* These relocs do not refer to symbols */
1414 continue;
1415 }
1416 break;
1417 }
1418
1419 check_section_mismatch(mod, elf, tsym,
1420 fsecndx, fromsec, r_offset, taddr);
1421 }
1422}
1423
1424static void section_rel(struct module *mod, struct elf_info *elf,
1425 unsigned int fsecndx, const char *fromsec,
1426 const Elf_Rel *start, const Elf_Rel *stop)
1427{
1428 const Elf_Rel *rel;
1429
1430 for (rel = start; rel < stop; rel++) {
1431 Elf_Sym *tsym;
1432 Elf_Addr taddr, r_offset;
1433 unsigned int r_type, r_sym;
1434 void *loc;
1435
1436 r_offset = TO_NATIVE(rel->r_offset);
1437 get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
1438
1439 loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
1440 tsym = elf->symtab_start + r_sym;
1441
1442 switch (elf->hdr->e_machine) {
1443 case EM_386:
1444 taddr = addend_386_rel(loc, r_type);
1445 break;
1446 case EM_ARM:
1447 taddr = addend_arm_rel(loc, tsym, r_type);
1448 break;
1449 case EM_MIPS:
1450 taddr = addend_mips_rel(loc, r_type);
1451 break;
1452 default:
1453 fatal("Please add code to calculate addend for this architecture\n");
1454 }
1455
1456 check_section_mismatch(mod, elf, tsym,
1457 fsecndx, fromsec, r_offset, taddr);
1458 }
1459}
1460
1461/**
1462 * A module includes a number of sections that are discarded
1463 * either when loaded or when used as built-in.
1464 * For loaded modules all functions marked __init and all data
1465 * marked __initdata will be discarded when the module has been initialized.
1466 * Likewise for modules used built-in the sections marked __exit
1467 * are discarded because __exit marked function are supposed to be called
1468 * only when a module is unloaded which never happens for built-in modules.
1469 * The check_sec_ref() function traverses all relocation records
1470 * to find all references to a section that reference a section that will
1471 * be discarded and warns about it.
1472 **/
1473static void check_sec_ref(struct module *mod, struct elf_info *elf)
1474{
1475 int i;
1476
1477 /* Walk through all sections */
1478 for (i = 0; i < elf->num_sections; i++) {
1479 Elf_Shdr *sechdr = &elf->sechdrs[i];
1480
1481 check_section(mod->name, elf, sechdr);
1482 /* We want to process only relocation sections and not .init */
1483 if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) {
1484 /* section to which the relocation applies */
1485 unsigned int secndx = sechdr->sh_info;
1486 const char *secname = sec_name(elf, secndx);
1487 const void *start, *stop;
1488
1489 /* If the section is known good, skip it */
1490 if (match(secname, section_white_list))
1491 continue;
1492
1493 start = sym_get_data_by_offset(elf, i, 0);
1494 stop = start + sechdr->sh_size;
1495
1496 if (sechdr->sh_type == SHT_RELA)
1497 section_rela(mod, elf, secndx, secname,
1498 start, stop);
1499 else
1500 section_rel(mod, elf, secndx, secname,
1501 start, stop);
1502 }
1503 }
1504}
1505
1506static char *remove_dot(char *s)
1507{
1508 size_t n = strcspn(s, ".");
1509
1510 if (n && s[n]) {
1511 size_t m = strspn(s + n + 1, "0123456789");
1512 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1513 s[n] = 0;
1514 }
1515 return s;
1516}
1517
1518/*
1519 * The CRCs are recorded in .*.cmd files in the form of:
1520 * #SYMVER <name> <crc>
1521 */
1522static void extract_crcs_for_object(const char *object, struct module *mod)
1523{
1524 char cmd_file[PATH_MAX];
1525 char *buf, *p;
1526 const char *base;
1527 int dirlen, ret;
1528
1529 base = strrchr(object, '/');
1530 if (base) {
1531 base++;
1532 dirlen = base - object;
1533 } else {
1534 dirlen = 0;
1535 base = object;
1536 }
1537
1538 ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
1539 dirlen, object, base);
1540 if (ret >= sizeof(cmd_file)) {
1541 error("%s: too long path was truncated\n", cmd_file);
1542 return;
1543 }
1544
1545 buf = read_text_file(cmd_file);
1546 p = buf;
1547
1548 while ((p = strstr(p, "\n#SYMVER "))) {
1549 char *name;
1550 size_t namelen;
1551 unsigned int crc;
1552 struct symbol *sym;
1553
1554 name = p + strlen("\n#SYMVER ");
1555
1556 p = strchr(name, ' ');
1557 if (!p)
1558 break;
1559
1560 namelen = p - name;
1561 p++;
1562
1563 if (!isdigit(*p))
1564 continue; /* skip this line */
1565
1566 crc = strtoul(p, &p, 0);
1567 if (*p != '\n')
1568 continue; /* skip this line */
1569
1570 name[namelen] = '\0';
1571
1572 /*
1573 * sym_find_with_module() may return NULL here.
1574 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1575 * Since commit e1327a127703, genksyms calculates CRCs of all
1576 * symbols, including trimmed ones. Ignore orphan CRCs.
1577 */
1578 sym = sym_find_with_module(name, mod);
1579 if (sym)
1580 sym_set_crc(sym, crc);
1581 }
1582
1583 free(buf);
1584}
1585
1586/*
1587 * The symbol versions (CRC) are recorded in the .*.cmd files.
1588 * Parse them to retrieve CRCs for the current module.
1589 */
1590static void mod_set_crcs(struct module *mod)
1591{
1592 char objlist[PATH_MAX];
1593 char *buf, *p, *obj;
1594 int ret;
1595
1596 if (mod->is_vmlinux) {
1597 strcpy(objlist, ".vmlinux.objs");
1598 } else {
1599 /* objects for a module are listed in the *.mod file. */
1600 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1601 if (ret >= sizeof(objlist)) {
1602 error("%s: too long path was truncated\n", objlist);
1603 return;
1604 }
1605 }
1606
1607 buf = read_text_file(objlist);
1608 p = buf;
1609
1610 while ((obj = strsep(&p, "\n")) && obj[0])
1611 extract_crcs_for_object(obj, mod);
1612
1613 free(buf);
1614}
1615
1616static void read_symbols(const char *modname)
1617{
1618 const char *symname;
1619 char *version;
1620 char *license;
1621 char *namespace;
1622 struct module *mod;
1623 struct elf_info info = { };
1624 Elf_Sym *sym;
1625
1626 if (!parse_elf(&info, modname))
1627 return;
1628
1629 if (!strends(modname, ".o")) {
1630 error("%s: filename must be suffixed with .o\n", modname);
1631 return;
1632 }
1633
1634 /* strip trailing .o */
1635 mod = new_module(modname, strlen(modname) - strlen(".o"));
1636
1637 if (!mod->is_vmlinux) {
1638 license = get_modinfo(&info, "license");
1639 if (!license)
1640 error("missing MODULE_LICENSE() in %s\n", modname);
1641 while (license) {
1642 if (!license_is_gpl_compatible(license)) {
1643 mod->is_gpl_compatible = false;
1644 break;
1645 }
1646 license = get_next_modinfo(&info, "license", license);
1647 }
1648
1649 namespace = get_modinfo(&info, "import_ns");
1650 while (namespace) {
1651 add_namespace(&mod->imported_namespaces, namespace);
1652 namespace = get_next_modinfo(&info, "import_ns",
1653 namespace);
1654 }
1655 }
1656
1657 if (extra_warn && !get_modinfo(&info, "description"))
1658 warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1659 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1660 symname = remove_dot(info.strtab + sym->st_name);
1661
1662 handle_symbol(mod, &info, sym, symname);
1663 handle_moddevtable(mod, &info, sym, symname);
1664 }
1665
1666 check_sec_ref(mod, &info);
1667
1668 if (!mod->is_vmlinux) {
1669 version = get_modinfo(&info, "version");
1670 if (version || all_versions)
1671 get_src_version(mod->name, mod->srcversion,
1672 sizeof(mod->srcversion) - 1);
1673 }
1674
1675 parse_elf_finish(&info);
1676
1677 if (modversions) {
1678 /*
1679 * Our trick to get versioning for module struct etc. - it's
1680 * never passed as an argument to an exported function, so
1681 * the automatic versioning doesn't pick it up, but it's really
1682 * important anyhow.
1683 */
1684 sym_add_unresolved("module_layout", mod, false);
1685
1686 mod_set_crcs(mod);
1687 }
1688}
1689
1690static void read_symbols_from_files(const char *filename)
1691{
1692 FILE *in = stdin;
1693 char fname[PATH_MAX];
1694
1695 in = fopen(filename, "r");
1696 if (!in)
1697 fatal("Can't open filenames file %s: %m", filename);
1698
1699 while (fgets(fname, PATH_MAX, in) != NULL) {
1700 if (strends(fname, "\n"))
1701 fname[strlen(fname)-1] = '\0';
1702 read_symbols(fname);
1703 }
1704
1705 fclose(in);
1706}
1707
1708#define SZ 500
1709
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 */
1713
1714void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1715 const char *fmt, ...)
1716{
1717 char tmp[SZ];
1718 int len;
1719 va_list ap;
1720
1721 va_start(ap, fmt);
1722 len = vsnprintf(tmp, SZ, fmt, ap);
1723 buf_write(buf, tmp, len);
1724 va_end(ap);
1725}
1726
1727void buf_write(struct buffer *buf, const char *s, int len)
1728{
1729 if (buf->size - buf->pos < len) {
1730 buf->size += len + SZ;
1731 buf->p = NOFAIL(realloc(buf->p, buf->size));
1732 }
1733 strncpy(buf->p + buf->pos, s, len);
1734 buf->pos += len;
1735}
1736
1737static void check_exports(struct module *mod)
1738{
1739 struct symbol *s, *exp;
1740
1741 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1742 const char *basename;
1743 exp = find_symbol(s->name);
1744 if (!exp) {
1745 if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1746 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
1747 "\"%s\" [%s.ko] undefined!\n",
1748 s->name, mod->name);
1749 continue;
1750 }
1751 if (exp->module == mod) {
1752 error("\"%s\" [%s.ko] was exported without definition\n",
1753 s->name, mod->name);
1754 continue;
1755 }
1756
1757 exp->used = true;
1758 s->module = exp->module;
1759 s->crc_valid = exp->crc_valid;
1760 s->crc = exp->crc;
1761
1762 basename = strrchr(mod->name, '/');
1763 if (basename)
1764 basename++;
1765 else
1766 basename = mod->name;
1767
1768 if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1769 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
1770 "module %s uses symbol %s from namespace %s, but does not import it.\n",
1771 basename, exp->name, exp->namespace);
1772 add_namespace(&mod->missing_namespaces, exp->namespace);
1773 }
1774
1775 if (!mod->is_gpl_compatible && exp->is_gpl_only)
1776 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1777 basename, exp->name);
1778 }
1779}
1780
1781static void handle_white_list_exports(const char *white_list)
1782{
1783 char *buf, *p, *name;
1784
1785 buf = read_text_file(white_list);
1786 p = buf;
1787
1788 while ((name = strsep(&p, "\n"))) {
1789 struct symbol *sym = find_symbol(name);
1790
1791 if (sym)
1792 sym->used = true;
1793 }
1794
1795 free(buf);
1796}
1797
1798static void check_modname_len(struct module *mod)
1799{
1800 const char *mod_name;
1801
1802 mod_name = strrchr(mod->name, '/');
1803 if (mod_name == NULL)
1804 mod_name = mod->name;
1805 else
1806 mod_name++;
1807 if (strlen(mod_name) >= MODULE_NAME_LEN)
1808 error("module name is too long [%s.ko]\n", mod->name);
1809}
1810
1811/**
1812 * Header for the generated file
1813 **/
1814static void add_header(struct buffer *b, struct module *mod)
1815{
1816 buf_printf(b, "#include <linux/module.h>\n");
1817 /*
1818 * Include build-salt.h after module.h in order to
1819 * inherit the definitions.
1820 */
1821 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
1822 buf_printf(b, "#include <linux/build-salt.h>\n");
1823 buf_printf(b, "#include <linux/elfnote-lto.h>\n");
1824 buf_printf(b, "#include <linux/export-internal.h>\n");
1825 buf_printf(b, "#include <linux/vermagic.h>\n");
1826 buf_printf(b, "#include <linux/compiler.h>\n");
1827 buf_printf(b, "\n");
1828 buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n");
1829 buf_printf(b, "#include <asm/orc_header.h>\n");
1830 buf_printf(b, "ORC_HEADER;\n");
1831 buf_printf(b, "#endif\n");
1832 buf_printf(b, "\n");
1833 buf_printf(b, "BUILD_SALT;\n");
1834 buf_printf(b, "BUILD_LTO_INFO;\n");
1835 buf_printf(b, "\n");
1836 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1837 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1838 buf_printf(b, "\n");
1839 buf_printf(b, "__visible struct module __this_module\n");
1840 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1841 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1842 if (mod->has_init)
1843 buf_printf(b, "\t.init = init_module,\n");
1844 if (mod->has_cleanup)
1845 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1846 "\t.exit = cleanup_module,\n"
1847 "#endif\n");
1848 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1849 buf_printf(b, "};\n");
1850
1851 if (!external_module)
1852 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1853
1854 buf_printf(b,
1855 "\n"
1856 "#ifdef CONFIG_MITIGATION_RETPOLINE\n"
1857 "MODULE_INFO(retpoline, \"Y\");\n"
1858 "#endif\n");
1859
1860 if (strstarts(mod->name, "drivers/staging"))
1861 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1862
1863 if (strstarts(mod->name, "tools/testing"))
1864 buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1865}
1866
1867static void add_exported_symbols(struct buffer *buf, struct module *mod)
1868{
1869 struct symbol *sym;
1870
1871 /* generate struct for exported symbols */
1872 buf_printf(buf, "\n");
1873 list_for_each_entry(sym, &mod->exported_symbols, list) {
1874 if (trim_unused_exports && !sym->used)
1875 continue;
1876
1877 buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1878 sym->is_func ? "FUNC" : "DATA", sym->name,
1879 sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1880 }
1881
1882 if (!modversions)
1883 return;
1884
1885 /* record CRCs for exported symbols */
1886 buf_printf(buf, "\n");
1887 list_for_each_entry(sym, &mod->exported_symbols, list) {
1888 if (trim_unused_exports && !sym->used)
1889 continue;
1890
1891 if (!sym->crc_valid)
1892 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1893 "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1894 sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1895 sym->name);
1896
1897 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1898 sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1899 }
1900}
1901
1902/**
1903 * Record CRCs for unresolved symbols
1904 **/
1905static void add_versions(struct buffer *b, struct module *mod)
1906{
1907 struct symbol *s;
1908
1909 if (!modversions)
1910 return;
1911
1912 buf_printf(b, "\n");
1913 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1914 buf_printf(b, "__used __section(\"__versions\") = {\n");
1915
1916 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1917 if (!s->module)
1918 continue;
1919 if (!s->crc_valid) {
1920 warn("\"%s\" [%s.ko] has no CRC!\n",
1921 s->name, mod->name);
1922 continue;
1923 }
1924 if (strlen(s->name) >= MODULE_NAME_LEN) {
1925 error("too long symbol \"%s\" [%s.ko]\n",
1926 s->name, mod->name);
1927 break;
1928 }
1929 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
1930 s->crc, s->name);
1931 }
1932
1933 buf_printf(b, "};\n");
1934}
1935
1936static void add_depends(struct buffer *b, struct module *mod)
1937{
1938 struct symbol *s;
1939 int first = 1;
1940
1941 /* Clear ->seen flag of modules that own symbols needed by this. */
1942 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1943 if (s->module)
1944 s->module->seen = s->module->is_vmlinux;
1945 }
1946
1947 buf_printf(b, "\n");
1948 buf_printf(b, "MODULE_INFO(depends, \"");
1949 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1950 const char *p;
1951 if (!s->module)
1952 continue;
1953
1954 if (s->module->seen)
1955 continue;
1956
1957 s->module->seen = true;
1958 p = strrchr(s->module->name, '/');
1959 if (p)
1960 p++;
1961 else
1962 p = s->module->name;
1963 buf_printf(b, "%s%s", first ? "" : ",", p);
1964 first = 0;
1965 }
1966 buf_printf(b, "\");\n");
1967}
1968
1969static void add_srcversion(struct buffer *b, struct module *mod)
1970{
1971 if (mod->srcversion[0]) {
1972 buf_printf(b, "\n");
1973 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1974 mod->srcversion);
1975 }
1976}
1977
1978static void write_buf(struct buffer *b, const char *fname)
1979{
1980 FILE *file;
1981
1982 if (error_occurred)
1983 return;
1984
1985 file = fopen(fname, "w");
1986 if (!file) {
1987 perror(fname);
1988 exit(1);
1989 }
1990 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1991 perror(fname);
1992 exit(1);
1993 }
1994 if (fclose(file) != 0) {
1995 perror(fname);
1996 exit(1);
1997 }
1998}
1999
2000static void write_if_changed(struct buffer *b, const char *fname)
2001{
2002 char *tmp;
2003 FILE *file;
2004 struct stat st;
2005
2006 file = fopen(fname, "r");
2007 if (!file)
2008 goto write;
2009
2010 if (fstat(fileno(file), &st) < 0)
2011 goto close_write;
2012
2013 if (st.st_size != b->pos)
2014 goto close_write;
2015
2016 tmp = NOFAIL(malloc(b->pos));
2017 if (fread(tmp, 1, b->pos, file) != b->pos)
2018 goto free_write;
2019
2020 if (memcmp(tmp, b->p, b->pos) != 0)
2021 goto free_write;
2022
2023 free(tmp);
2024 fclose(file);
2025 return;
2026
2027 free_write:
2028 free(tmp);
2029 close_write:
2030 fclose(file);
2031 write:
2032 write_buf(b, fname);
2033}
2034
2035static void write_vmlinux_export_c_file(struct module *mod)
2036{
2037 struct buffer buf = { };
2038
2039 buf_printf(&buf,
2040 "#include <linux/export-internal.h>\n");
2041
2042 add_exported_symbols(&buf, mod);
2043 write_if_changed(&buf, ".vmlinux.export.c");
2044 free(buf.p);
2045}
2046
2047/* do sanity checks, and generate *.mod.c file */
2048static void write_mod_c_file(struct module *mod)
2049{
2050 struct buffer buf = { };
2051 char fname[PATH_MAX];
2052 int ret;
2053
2054 add_header(&buf, mod);
2055 add_exported_symbols(&buf, mod);
2056 add_versions(&buf, mod);
2057 add_depends(&buf, mod);
2058 add_moddevtable(&buf, mod);
2059 add_srcversion(&buf, mod);
2060
2061 ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
2062 if (ret >= sizeof(fname)) {
2063 error("%s: too long path was truncated\n", fname);
2064 goto free;
2065 }
2066
2067 write_if_changed(&buf, fname);
2068
2069free:
2070 free(buf.p);
2071}
2072
2073/* parse Module.symvers file. line format:
2074 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2075 **/
2076static void read_dump(const char *fname)
2077{
2078 char *buf, *pos, *line;
2079
2080 buf = read_text_file(fname);
2081 if (!buf)
2082 /* No symbol versions, silently ignore */
2083 return;
2084
2085 pos = buf;
2086
2087 while ((line = get_line(&pos))) {
2088 char *symname, *namespace, *modname, *d, *export;
2089 unsigned int crc;
2090 struct module *mod;
2091 struct symbol *s;
2092 bool gpl_only;
2093
2094 if (!(symname = strchr(line, '\t')))
2095 goto fail;
2096 *symname++ = '\0';
2097 if (!(modname = strchr(symname, '\t')))
2098 goto fail;
2099 *modname++ = '\0';
2100 if (!(export = strchr(modname, '\t')))
2101 goto fail;
2102 *export++ = '\0';
2103 if (!(namespace = strchr(export, '\t')))
2104 goto fail;
2105 *namespace++ = '\0';
2106
2107 crc = strtoul(line, &d, 16);
2108 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2109 goto fail;
2110
2111 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2112 gpl_only = true;
2113 } else if (!strcmp(export, "EXPORT_SYMBOL")) {
2114 gpl_only = false;
2115 } else {
2116 error("%s: unknown license %s. skip", symname, export);
2117 continue;
2118 }
2119
2120 mod = find_module(modname);
2121 if (!mod) {
2122 mod = new_module(modname, strlen(modname));
2123 mod->from_dump = true;
2124 }
2125 s = sym_add_exported(symname, mod, gpl_only, namespace);
2126 sym_set_crc(s, crc);
2127 }
2128 free(buf);
2129 return;
2130fail:
2131 free(buf);
2132 fatal("parse error in symbol dump file\n");
2133}
2134
2135static void write_dump(const char *fname)
2136{
2137 struct buffer buf = { };
2138 struct module *mod;
2139 struct symbol *sym;
2140
2141 list_for_each_entry(mod, &modules, list) {
2142 if (mod->from_dump)
2143 continue;
2144 list_for_each_entry(sym, &mod->exported_symbols, list) {
2145 if (trim_unused_exports && !sym->used)
2146 continue;
2147
2148 buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2149 sym->crc, sym->name, mod->name,
2150 sym->is_gpl_only ? "_GPL" : "",
2151 sym->namespace);
2152 }
2153 }
2154 write_buf(&buf, fname);
2155 free(buf.p);
2156}
2157
2158static void write_namespace_deps_files(const char *fname)
2159{
2160 struct module *mod;
2161 struct namespace_list *ns;
2162 struct buffer ns_deps_buf = {};
2163
2164 list_for_each_entry(mod, &modules, list) {
2165
2166 if (mod->from_dump || list_empty(&mod->missing_namespaces))
2167 continue;
2168
2169 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2170
2171 list_for_each_entry(ns, &mod->missing_namespaces, list)
2172 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2173
2174 buf_printf(&ns_deps_buf, "\n");
2175 }
2176
2177 write_if_changed(&ns_deps_buf, fname);
2178 free(ns_deps_buf.p);
2179}
2180
2181struct dump_list {
2182 struct list_head list;
2183 const char *file;
2184};
2185
2186int main(int argc, char **argv)
2187{
2188 struct module *mod;
2189 char *missing_namespace_deps = NULL;
2190 char *unused_exports_white_list = NULL;
2191 char *dump_write = NULL, *files_source = NULL;
2192 int opt;
2193 LIST_HEAD(dump_lists);
2194 struct dump_list *dl, *dl2;
2195
2196 while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
2197 switch (opt) {
2198 case 'e':
2199 external_module = true;
2200 break;
2201 case 'i':
2202 dl = NOFAIL(malloc(sizeof(*dl)));
2203 dl->file = optarg;
2204 list_add_tail(&dl->list, &dump_lists);
2205 break;
2206 case 'M':
2207 module_enabled = true;
2208 break;
2209 case 'm':
2210 modversions = true;
2211 break;
2212 case 'n':
2213 ignore_missing_files = true;
2214 break;
2215 case 'o':
2216 dump_write = optarg;
2217 break;
2218 case 'a':
2219 all_versions = true;
2220 break;
2221 case 'T':
2222 files_source = optarg;
2223 break;
2224 case 't':
2225 trim_unused_exports = true;
2226 break;
2227 case 'u':
2228 unused_exports_white_list = optarg;
2229 break;
2230 case 'W':
2231 extra_warn = true;
2232 break;
2233 case 'w':
2234 warn_unresolved = true;
2235 break;
2236 case 'E':
2237 sec_mismatch_warn_only = false;
2238 break;
2239 case 'N':
2240 allow_missing_ns_imports = true;
2241 break;
2242 case 'd':
2243 missing_namespace_deps = optarg;
2244 break;
2245 default:
2246 exit(1);
2247 }
2248 }
2249
2250 list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2251 read_dump(dl->file);
2252 list_del(&dl->list);
2253 free(dl);
2254 }
2255
2256 while (optind < argc)
2257 read_symbols(argv[optind++]);
2258
2259 if (files_source)
2260 read_symbols_from_files(files_source);
2261
2262 list_for_each_entry(mod, &modules, list) {
2263 if (mod->from_dump || mod->is_vmlinux)
2264 continue;
2265
2266 check_modname_len(mod);
2267 check_exports(mod);
2268 }
2269
2270 if (unused_exports_white_list)
2271 handle_white_list_exports(unused_exports_white_list);
2272
2273 list_for_each_entry(mod, &modules, list) {
2274 if (mod->from_dump)
2275 continue;
2276
2277 if (mod->is_vmlinux)
2278 write_vmlinux_export_c_file(mod);
2279 else
2280 write_mod_c_file(mod);
2281 }
2282
2283 if (missing_namespace_deps)
2284 write_namespace_deps_files(missing_namespace_deps);
2285
2286 if (dump_write)
2287 write_dump(dump_write);
2288 if (sec_mismatch_count && !sec_mismatch_warn_only)
2289 error("Section mismatches detected.\n"
2290 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2291
2292 if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2293 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2294 nr_unresolved - MAX_UNRESOLVED_REPORTS);
2295
2296 return error_occurred ? 1 : 0;
2297}