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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 <stdio.h>
16#include <ctype.h>
17#include <string.h>
18#include "modpost.h"
19#include "../../include/generated/autoconf.h"
20#include "../../include/linux/license.h"
21
22/* Some toolchains use a `_' prefix for all user symbols. */
23#ifdef CONFIG_SYMBOL_PREFIX
24#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
25#else
26#define MODULE_SYMBOL_PREFIX ""
27#endif
28
29
30/* Are we using CONFIG_MODVERSIONS? */
31int modversions = 0;
32/* Warn about undefined symbols? (do so if we have vmlinux) */
33int have_vmlinux = 0;
34/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
35static int all_versions = 0;
36/* If we are modposting external module set to 1 */
37static int external_module = 0;
38/* Warn about section mismatch in vmlinux if set to 1 */
39static int vmlinux_section_warnings = 1;
40/* Only warn about unresolved symbols */
41static int warn_unresolved = 0;
42/* How a symbol is exported */
43static int sec_mismatch_count = 0;
44static int sec_mismatch_verbose = 1;
45
46enum export {
47 export_plain, export_unused, export_gpl,
48 export_unused_gpl, export_gpl_future, export_unknown
49};
50
51#define PRINTF __attribute__ ((format (printf, 1, 2)))
52
53PRINTF void fatal(const char *fmt, ...)
54{
55 va_list arglist;
56
57 fprintf(stderr, "FATAL: ");
58
59 va_start(arglist, fmt);
60 vfprintf(stderr, fmt, arglist);
61 va_end(arglist);
62
63 exit(1);
64}
65
66PRINTF void warn(const char *fmt, ...)
67{
68 va_list arglist;
69
70 fprintf(stderr, "WARNING: ");
71
72 va_start(arglist, fmt);
73 vfprintf(stderr, fmt, arglist);
74 va_end(arglist);
75}
76
77PRINTF void merror(const char *fmt, ...)
78{
79 va_list arglist;
80
81 fprintf(stderr, "ERROR: ");
82
83 va_start(arglist, fmt);
84 vfprintf(stderr, fmt, arglist);
85 va_end(arglist);
86}
87
88static int is_vmlinux(const char *modname)
89{
90 const char *myname;
91
92 myname = strrchr(modname, '/');
93 if (myname)
94 myname++;
95 else
96 myname = modname;
97
98 return (strcmp(myname, "vmlinux") == 0) ||
99 (strcmp(myname, "vmlinux.o") == 0);
100}
101
102void *do_nofail(void *ptr, const char *expr)
103{
104 if (!ptr)
105 fatal("modpost: Memory allocation failure: %s.\n", expr);
106
107 return ptr;
108}
109
110/* A list of all modules we processed */
111static struct module *modules;
112
113static struct module *find_module(char *modname)
114{
115 struct module *mod;
116
117 for (mod = modules; mod; mod = mod->next)
118 if (strcmp(mod->name, modname) == 0)
119 break;
120 return mod;
121}
122
123static struct module *new_module(char *modname)
124{
125 struct module *mod;
126 char *p, *s;
127
128 mod = NOFAIL(malloc(sizeof(*mod)));
129 memset(mod, 0, sizeof(*mod));
130 p = NOFAIL(strdup(modname));
131
132 /* strip trailing .o */
133 s = strrchr(p, '.');
134 if (s != NULL)
135 if (strcmp(s, ".o") == 0) {
136 *s = '\0';
137 mod->is_dot_o = 1;
138 }
139
140 /* add to list */
141 mod->name = p;
142 mod->gpl_compatible = -1;
143 mod->next = modules;
144 modules = mod;
145
146 return mod;
147}
148
149/* A hash of all exported symbols,
150 * struct symbol is also used for lists of unresolved symbols */
151
152#define SYMBOL_HASH_SIZE 1024
153
154struct symbol {
155 struct symbol *next;
156 struct module *module;
157 unsigned int crc;
158 int crc_valid;
159 unsigned int weak:1;
160 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
161 unsigned int kernel:1; /* 1 if symbol is from kernel
162 * (only for external modules) **/
163 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
164 enum export export; /* Type of export */
165 char name[0];
166};
167
168static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
169
170/* This is based on the hash agorithm from gdbm, via tdb */
171static inline unsigned int tdb_hash(const char *name)
172{
173 unsigned value; /* Used to compute the hash value. */
174 unsigned i; /* Used to cycle through random values. */
175
176 /* Set the initial value from the key size. */
177 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
178 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
179
180 return (1103515243 * value + 12345);
181}
182
183/**
184 * Allocate a new symbols for use in the hash of exported symbols or
185 * the list of unresolved symbols per module
186 **/
187static struct symbol *alloc_symbol(const char *name, unsigned int weak,
188 struct symbol *next)
189{
190 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
191
192 memset(s, 0, sizeof(*s));
193 strcpy(s->name, name);
194 s->weak = weak;
195 s->next = next;
196 return s;
197}
198
199/* For the hash of exported symbols */
200static struct symbol *new_symbol(const char *name, struct module *module,
201 enum export export)
202{
203 unsigned int hash;
204 struct symbol *new;
205
206 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
207 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
208 new->module = module;
209 new->export = export;
210 return new;
211}
212
213static struct symbol *find_symbol(const char *name)
214{
215 struct symbol *s;
216
217 /* For our purposes, .foo matches foo. PPC64 needs this. */
218 if (name[0] == '.')
219 name++;
220
221 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
222 if (strcmp(s->name, name) == 0)
223 return s;
224 }
225 return NULL;
226}
227
228static struct {
229 const char *str;
230 enum export export;
231} export_list[] = {
232 { .str = "EXPORT_SYMBOL", .export = export_plain },
233 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
234 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
235 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
236 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
237 { .str = "(unknown)", .export = export_unknown },
238};
239
240
241static const char *export_str(enum export ex)
242{
243 return export_list[ex].str;
244}
245
246static enum export export_no(const char *s)
247{
248 int i;
249
250 if (!s)
251 return export_unknown;
252 for (i = 0; export_list[i].export != export_unknown; i++) {
253 if (strcmp(export_list[i].str, s) == 0)
254 return export_list[i].export;
255 }
256 return export_unknown;
257}
258
259static const char *sec_name(struct elf_info *elf, int secindex);
260
261#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
262
263static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
264{
265 const char *secname = sec_name(elf, sec);
266
267 if (strstarts(secname, "___ksymtab+"))
268 return export_plain;
269 else if (strstarts(secname, "___ksymtab_unused+"))
270 return export_unused;
271 else if (strstarts(secname, "___ksymtab_gpl+"))
272 return export_gpl;
273 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
274 return export_unused_gpl;
275 else if (strstarts(secname, "___ksymtab_gpl_future+"))
276 return export_gpl_future;
277 else
278 return export_unknown;
279}
280
281static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
282{
283 if (sec == elf->export_sec)
284 return export_plain;
285 else if (sec == elf->export_unused_sec)
286 return export_unused;
287 else if (sec == elf->export_gpl_sec)
288 return export_gpl;
289 else if (sec == elf->export_unused_gpl_sec)
290 return export_unused_gpl;
291 else if (sec == elf->export_gpl_future_sec)
292 return export_gpl_future;
293 else
294 return export_unknown;
295}
296
297/**
298 * Add an exported symbol - it may have already been added without a
299 * CRC, in this case just update the CRC
300 **/
301static struct symbol *sym_add_exported(const char *name, struct module *mod,
302 enum export export)
303{
304 struct symbol *s = find_symbol(name);
305
306 if (!s) {
307 s = new_symbol(name, mod, export);
308 } else {
309 if (!s->preloaded) {
310 warn("%s: '%s' exported twice. Previous export "
311 "was in %s%s\n", mod->name, name,
312 s->module->name,
313 is_vmlinux(s->module->name) ?"":".ko");
314 } else {
315 /* In case Modules.symvers was out of date */
316 s->module = mod;
317 }
318 }
319 s->preloaded = 0;
320 s->vmlinux = is_vmlinux(mod->name);
321 s->kernel = 0;
322 s->export = export;
323 return s;
324}
325
326static void sym_update_crc(const char *name, struct module *mod,
327 unsigned int crc, enum export export)
328{
329 struct symbol *s = find_symbol(name);
330
331 if (!s)
332 s = new_symbol(name, mod, export);
333 s->crc = crc;
334 s->crc_valid = 1;
335}
336
337void *grab_file(const char *filename, unsigned long *size)
338{
339 struct stat st;
340 void *map = MAP_FAILED;
341 int fd;
342
343 fd = open(filename, O_RDONLY);
344 if (fd < 0)
345 return NULL;
346 if (fstat(fd, &st))
347 goto failed;
348
349 *size = st.st_size;
350 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
351
352failed:
353 close(fd);
354 if (map == MAP_FAILED)
355 return NULL;
356 return map;
357}
358
359/**
360 * Return a copy of the next line in a mmap'ed file.
361 * spaces in the beginning of the line is trimmed away.
362 * Return a pointer to a static buffer.
363 **/
364char *get_next_line(unsigned long *pos, void *file, unsigned long size)
365{
366 static char line[4096];
367 int skip = 1;
368 size_t len = 0;
369 signed char *p = (signed char *)file + *pos;
370 char *s = line;
371
372 for (; *pos < size ; (*pos)++) {
373 if (skip && isspace(*p)) {
374 p++;
375 continue;
376 }
377 skip = 0;
378 if (*p != '\n' && (*pos < size)) {
379 len++;
380 *s++ = *p++;
381 if (len > 4095)
382 break; /* Too long, stop */
383 } else {
384 /* End of string */
385 *s = '\0';
386 return line;
387 }
388 }
389 /* End of buffer */
390 return NULL;
391}
392
393void release_file(void *file, unsigned long size)
394{
395 munmap(file, size);
396}
397
398static int parse_elf(struct elf_info *info, const char *filename)
399{
400 unsigned int i;
401 Elf_Ehdr *hdr;
402 Elf_Shdr *sechdrs;
403 Elf_Sym *sym;
404 const char *secstrings;
405 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
406
407 hdr = grab_file(filename, &info->size);
408 if (!hdr) {
409 perror(filename);
410 exit(1);
411 }
412 info->hdr = hdr;
413 if (info->size < sizeof(*hdr)) {
414 /* file too small, assume this is an empty .o file */
415 return 0;
416 }
417 /* Is this a valid ELF file? */
418 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
419 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
420 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
421 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
422 /* Not an ELF file - silently ignore it */
423 return 0;
424 }
425 /* Fix endianness in ELF header */
426 hdr->e_type = TO_NATIVE(hdr->e_type);
427 hdr->e_machine = TO_NATIVE(hdr->e_machine);
428 hdr->e_version = TO_NATIVE(hdr->e_version);
429 hdr->e_entry = TO_NATIVE(hdr->e_entry);
430 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
431 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
432 hdr->e_flags = TO_NATIVE(hdr->e_flags);
433 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
434 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
435 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
436 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
437 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
438 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
439 sechdrs = (void *)hdr + hdr->e_shoff;
440 info->sechdrs = sechdrs;
441
442 /* Check if file offset is correct */
443 if (hdr->e_shoff > info->size) {
444 fatal("section header offset=%lu in file '%s' is bigger than "
445 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
446 filename, info->size);
447 return 0;
448 }
449
450 if (hdr->e_shnum == SHN_UNDEF) {
451 /*
452 * There are more than 64k sections,
453 * read count from .sh_size.
454 */
455 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
456 }
457 else {
458 info->num_sections = hdr->e_shnum;
459 }
460 if (hdr->e_shstrndx == SHN_XINDEX) {
461 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
462 }
463 else {
464 info->secindex_strings = hdr->e_shstrndx;
465 }
466
467 /* Fix endianness in section headers */
468 for (i = 0; i < info->num_sections; i++) {
469 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
470 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
471 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
472 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
473 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
474 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
475 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
476 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
477 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
478 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
479 }
480 /* Find symbol table. */
481 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
482 for (i = 1; i < info->num_sections; i++) {
483 const char *secname;
484 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
485
486 if (!nobits && sechdrs[i].sh_offset > info->size) {
487 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
488 "sizeof(*hrd)=%zu\n", filename,
489 (unsigned long)sechdrs[i].sh_offset,
490 sizeof(*hdr));
491 return 0;
492 }
493 secname = secstrings + sechdrs[i].sh_name;
494 if (strcmp(secname, ".modinfo") == 0) {
495 if (nobits)
496 fatal("%s has NOBITS .modinfo\n", filename);
497 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
498 info->modinfo_len = sechdrs[i].sh_size;
499 } else if (strcmp(secname, "__ksymtab") == 0)
500 info->export_sec = i;
501 else if (strcmp(secname, "__ksymtab_unused") == 0)
502 info->export_unused_sec = i;
503 else if (strcmp(secname, "__ksymtab_gpl") == 0)
504 info->export_gpl_sec = i;
505 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
506 info->export_unused_gpl_sec = i;
507 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
508 info->export_gpl_future_sec = i;
509
510 if (sechdrs[i].sh_type == SHT_SYMTAB) {
511 unsigned int sh_link_idx;
512 symtab_idx = i;
513 info->symtab_start = (void *)hdr +
514 sechdrs[i].sh_offset;
515 info->symtab_stop = (void *)hdr +
516 sechdrs[i].sh_offset + sechdrs[i].sh_size;
517 sh_link_idx = sechdrs[i].sh_link;
518 info->strtab = (void *)hdr +
519 sechdrs[sh_link_idx].sh_offset;
520 }
521
522 /* 32bit section no. table? ("more than 64k sections") */
523 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
524 symtab_shndx_idx = i;
525 info->symtab_shndx_start = (void *)hdr +
526 sechdrs[i].sh_offset;
527 info->symtab_shndx_stop = (void *)hdr +
528 sechdrs[i].sh_offset + sechdrs[i].sh_size;
529 }
530 }
531 if (!info->symtab_start)
532 fatal("%s has no symtab?\n", filename);
533
534 /* Fix endianness in symbols */
535 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
536 sym->st_shndx = TO_NATIVE(sym->st_shndx);
537 sym->st_name = TO_NATIVE(sym->st_name);
538 sym->st_value = TO_NATIVE(sym->st_value);
539 sym->st_size = TO_NATIVE(sym->st_size);
540 }
541
542 if (symtab_shndx_idx != ~0U) {
543 Elf32_Word *p;
544 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
545 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
546 filename, sechdrs[symtab_shndx_idx].sh_link,
547 symtab_idx);
548 /* Fix endianness */
549 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
550 p++)
551 *p = TO_NATIVE(*p);
552 }
553
554 return 1;
555}
556
557static void parse_elf_finish(struct elf_info *info)
558{
559 release_file(info->hdr, info->size);
560}
561
562static int ignore_undef_symbol(struct elf_info *info, const char *symname)
563{
564 /* ignore __this_module, it will be resolved shortly */
565 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
566 return 1;
567 /* ignore global offset table */
568 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
569 return 1;
570 if (info->hdr->e_machine == EM_PPC)
571 /* Special register function linked on all modules during final link of .ko */
572 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
573 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
574 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
575 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
576 return 1;
577 if (info->hdr->e_machine == EM_PPC64)
578 /* Special register function linked on all modules during final link of .ko */
579 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
580 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
581 return 1;
582 /* Do not ignore this symbol */
583 return 0;
584}
585
586#define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
587#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
588
589static void handle_modversions(struct module *mod, struct elf_info *info,
590 Elf_Sym *sym, const char *symname)
591{
592 unsigned int crc;
593 enum export export;
594
595 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
596 strncmp(symname, "__ksymtab", 9) == 0)
597 export = export_from_secname(info, get_secindex(info, sym));
598 else
599 export = export_from_sec(info, get_secindex(info, sym));
600
601 switch (sym->st_shndx) {
602 case SHN_COMMON:
603 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
604 break;
605 case SHN_ABS:
606 /* CRC'd symbol */
607 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
608 crc = (unsigned int) sym->st_value;
609 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
610 export);
611 }
612 break;
613 case SHN_UNDEF:
614 /* undefined symbol */
615 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
616 ELF_ST_BIND(sym->st_info) != STB_WEAK)
617 break;
618 if (ignore_undef_symbol(info, symname))
619 break;
620/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
621#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
622/* add compatibility with older glibc */
623#ifndef STT_SPARC_REGISTER
624#define STT_SPARC_REGISTER STT_REGISTER
625#endif
626 if (info->hdr->e_machine == EM_SPARC ||
627 info->hdr->e_machine == EM_SPARCV9) {
628 /* Ignore register directives. */
629 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
630 break;
631 if (symname[0] == '.') {
632 char *munged = strdup(symname);
633 munged[0] = '_';
634 munged[1] = toupper(munged[1]);
635 symname = munged;
636 }
637 }
638#endif
639
640 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
641 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
642 mod->unres =
643 alloc_symbol(symname +
644 strlen(MODULE_SYMBOL_PREFIX),
645 ELF_ST_BIND(sym->st_info) == STB_WEAK,
646 mod->unres);
647 }
648 break;
649 default:
650 /* All exported symbols */
651 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
652 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
653 export);
654 }
655 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
656 mod->has_init = 1;
657 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
658 mod->has_cleanup = 1;
659 break;
660 }
661}
662
663/**
664 * Parse tag=value strings from .modinfo section
665 **/
666static char *next_string(char *string, unsigned long *secsize)
667{
668 /* Skip non-zero chars */
669 while (string[0]) {
670 string++;
671 if ((*secsize)-- <= 1)
672 return NULL;
673 }
674
675 /* Skip any zero padding. */
676 while (!string[0]) {
677 string++;
678 if ((*secsize)-- <= 1)
679 return NULL;
680 }
681 return string;
682}
683
684static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
685 const char *tag, char *info)
686{
687 char *p;
688 unsigned int taglen = strlen(tag);
689 unsigned long size = modinfo_len;
690
691 if (info) {
692 size -= info - (char *)modinfo;
693 modinfo = next_string(info, &size);
694 }
695
696 for (p = modinfo; p; p = next_string(p, &size)) {
697 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
698 return p + taglen + 1;
699 }
700 return NULL;
701}
702
703static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
704 const char *tag)
705
706{
707 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
708}
709
710/**
711 * Test if string s ends in string sub
712 * return 0 if match
713 **/
714static int strrcmp(const char *s, const char *sub)
715{
716 int slen, sublen;
717
718 if (!s || !sub)
719 return 1;
720
721 slen = strlen(s);
722 sublen = strlen(sub);
723
724 if ((slen == 0) || (sublen == 0))
725 return 1;
726
727 if (sublen > slen)
728 return 1;
729
730 return memcmp(s + slen - sublen, sub, sublen);
731}
732
733static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
734{
735 if (sym)
736 return elf->strtab + sym->st_name;
737 else
738 return "(unknown)";
739}
740
741static const char *sec_name(struct elf_info *elf, int secindex)
742{
743 Elf_Shdr *sechdrs = elf->sechdrs;
744 return (void *)elf->hdr +
745 elf->sechdrs[elf->secindex_strings].sh_offset +
746 sechdrs[secindex].sh_name;
747}
748
749static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
750{
751 return (void *)elf->hdr +
752 elf->sechdrs[elf->secindex_strings].sh_offset +
753 sechdr->sh_name;
754}
755
756/* if sym is empty or point to a string
757 * like ".[0-9]+" then return 1.
758 * This is the optional prefix added by ld to some sections
759 */
760static int number_prefix(const char *sym)
761{
762 if (*sym++ == '\0')
763 return 1;
764 if (*sym != '.')
765 return 0;
766 do {
767 char c = *sym++;
768 if (c < '0' || c > '9')
769 return 0;
770 } while (*sym);
771 return 1;
772}
773
774/* The pattern is an array of simple patterns.
775 * "foo" will match an exact string equal to "foo"
776 * "*foo" will match a string that ends with "foo"
777 * "foo*" will match a string that begins with "foo"
778 * "foo$" will match a string equal to "foo" or "foo.1"
779 * where the '1' can be any number including several digits.
780 * The $ syntax is for sections where ld append a dot number
781 * to make section name unique.
782 */
783static int match(const char *sym, const char * const pat[])
784{
785 const char *p;
786 while (*pat) {
787 p = *pat++;
788 const char *endp = p + strlen(p) - 1;
789
790 /* "*foo" */
791 if (*p == '*') {
792 if (strrcmp(sym, p + 1) == 0)
793 return 1;
794 }
795 /* "foo*" */
796 else if (*endp == '*') {
797 if (strncmp(sym, p, strlen(p) - 1) == 0)
798 return 1;
799 }
800 /* "foo$" */
801 else if (*endp == '$') {
802 if (strncmp(sym, p, strlen(p) - 1) == 0) {
803 if (number_prefix(sym + strlen(p) - 1))
804 return 1;
805 }
806 }
807 /* no wildcards */
808 else {
809 if (strcmp(p, sym) == 0)
810 return 1;
811 }
812 }
813 /* no match */
814 return 0;
815}
816
817/* sections that we do not want to do full section mismatch check on */
818static const char *section_white_list[] =
819{
820 ".comment*",
821 ".debug*",
822 ".zdebug*", /* Compressed debug sections. */
823 ".GCC-command-line", /* mn10300 */
824 ".mdebug*", /* alpha, score, mips etc. */
825 ".pdr", /* alpha, score, mips etc. */
826 ".stab*",
827 ".note*",
828 ".got*",
829 ".toc*",
830 NULL
831};
832
833/*
834 * This is used to find sections missing the SHF_ALLOC flag.
835 * The cause of this is often a section specified in assembler
836 * without "ax" / "aw".
837 */
838static void check_section(const char *modname, struct elf_info *elf,
839 Elf_Shdr *sechdr)
840{
841 const char *sec = sech_name(elf, sechdr);
842
843 if (sechdr->sh_type == SHT_PROGBITS &&
844 !(sechdr->sh_flags & SHF_ALLOC) &&
845 !match(sec, section_white_list)) {
846 warn("%s (%s): unexpected non-allocatable section.\n"
847 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
848 "Note that for example <linux/init.h> contains\n"
849 "section definitions for use in .S files.\n\n",
850 modname, sec);
851 }
852}
853
854
855
856#define ALL_INIT_DATA_SECTIONS \
857 ".init.setup$", ".init.rodata$", \
858 ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$", \
859 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
860#define ALL_EXIT_DATA_SECTIONS \
861 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
862
863#define ALL_INIT_TEXT_SECTIONS \
864 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
865#define ALL_EXIT_TEXT_SECTIONS \
866 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
867
868#define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
869 MEM_INIT_SECTIONS
870#define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
871 MEM_EXIT_SECTIONS
872
873#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
874#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
875
876#define DATA_SECTIONS ".data$", ".data.rel$"
877#define TEXT_SECTIONS ".text$"
878
879#define INIT_SECTIONS ".init.*"
880#define DEV_INIT_SECTIONS ".devinit.*"
881#define CPU_INIT_SECTIONS ".cpuinit.*"
882#define MEM_INIT_SECTIONS ".meminit.*"
883
884#define EXIT_SECTIONS ".exit.*"
885#define DEV_EXIT_SECTIONS ".devexit.*"
886#define CPU_EXIT_SECTIONS ".cpuexit.*"
887#define MEM_EXIT_SECTIONS ".memexit.*"
888
889/* init data sections */
890static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
891
892/* all init sections */
893static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
894
895/* All init and exit sections (code + data) */
896static const char *init_exit_sections[] =
897 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
898
899/* data section */
900static const char *data_sections[] = { DATA_SECTIONS, NULL };
901
902
903/* symbols in .data that may refer to init/exit sections */
904#define DEFAULT_SYMBOL_WHITE_LIST \
905 "*driver", \
906 "*_template", /* scsi uses *_template a lot */ \
907 "*_timer", /* arm uses ops structures named _timer a lot */ \
908 "*_sht", /* scsi also used *_sht to some extent */ \
909 "*_ops", \
910 "*_probe", \
911 "*_probe_one", \
912 "*_console"
913
914static const char *head_sections[] = { ".head.text*", NULL };
915static const char *linker_symbols[] =
916 { "__init_begin", "_sinittext", "_einittext", NULL };
917
918enum mismatch {
919 TEXT_TO_ANY_INIT,
920 DATA_TO_ANY_INIT,
921 TEXT_TO_ANY_EXIT,
922 DATA_TO_ANY_EXIT,
923 XXXINIT_TO_SOME_INIT,
924 XXXEXIT_TO_SOME_EXIT,
925 ANY_INIT_TO_ANY_EXIT,
926 ANY_EXIT_TO_ANY_INIT,
927 EXPORT_TO_INIT_EXIT,
928};
929
930struct sectioncheck {
931 const char *fromsec[20];
932 const char *tosec[20];
933 enum mismatch mismatch;
934 const char *symbol_white_list[20];
935};
936
937const struct sectioncheck sectioncheck[] = {
938/* Do not reference init/exit code/data from
939 * normal code and data
940 */
941{
942 .fromsec = { TEXT_SECTIONS, NULL },
943 .tosec = { ALL_INIT_SECTIONS, NULL },
944 .mismatch = TEXT_TO_ANY_INIT,
945 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
946},
947{
948 .fromsec = { DATA_SECTIONS, NULL },
949 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
950 .mismatch = DATA_TO_ANY_INIT,
951 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
952},
953{
954 .fromsec = { DATA_SECTIONS, NULL },
955 .tosec = { INIT_SECTIONS, NULL },
956 .mismatch = DATA_TO_ANY_INIT,
957 .symbol_white_list = {
958 "*_template", "*_timer", "*_sht", "*_ops",
959 "*_probe", "*_probe_one", "*_console", NULL
960 },
961},
962{
963 .fromsec = { TEXT_SECTIONS, NULL },
964 .tosec = { ALL_EXIT_SECTIONS, NULL },
965 .mismatch = TEXT_TO_ANY_EXIT,
966 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
967},
968{
969 .fromsec = { DATA_SECTIONS, NULL },
970 .tosec = { ALL_EXIT_SECTIONS, NULL },
971 .mismatch = DATA_TO_ANY_EXIT,
972 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
973},
974/* Do not reference init code/data from devinit/cpuinit/meminit code/data */
975{
976 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
977 .tosec = { INIT_SECTIONS, NULL },
978 .mismatch = XXXINIT_TO_SOME_INIT,
979 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
980},
981/* Do not reference cpuinit code/data from meminit code/data */
982{
983 .fromsec = { MEM_INIT_SECTIONS, NULL },
984 .tosec = { CPU_INIT_SECTIONS, NULL },
985 .mismatch = XXXINIT_TO_SOME_INIT,
986 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
987},
988/* Do not reference meminit code/data from cpuinit code/data */
989{
990 .fromsec = { CPU_INIT_SECTIONS, NULL },
991 .tosec = { MEM_INIT_SECTIONS, NULL },
992 .mismatch = XXXINIT_TO_SOME_INIT,
993 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
994},
995/* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
996{
997 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
998 .tosec = { EXIT_SECTIONS, NULL },
999 .mismatch = XXXEXIT_TO_SOME_EXIT,
1000 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1001},
1002/* Do not reference cpuexit code/data from memexit code/data */
1003{
1004 .fromsec = { MEM_EXIT_SECTIONS, NULL },
1005 .tosec = { CPU_EXIT_SECTIONS, NULL },
1006 .mismatch = XXXEXIT_TO_SOME_EXIT,
1007 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1008},
1009/* Do not reference memexit code/data from cpuexit code/data */
1010{
1011 .fromsec = { CPU_EXIT_SECTIONS, NULL },
1012 .tosec = { MEM_EXIT_SECTIONS, NULL },
1013 .mismatch = XXXEXIT_TO_SOME_EXIT,
1014 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1015},
1016/* Do not use exit code/data from init code */
1017{
1018 .fromsec = { ALL_INIT_SECTIONS, NULL },
1019 .tosec = { ALL_EXIT_SECTIONS, NULL },
1020 .mismatch = ANY_INIT_TO_ANY_EXIT,
1021 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1022},
1023/* Do not use init code/data from exit code */
1024{
1025 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1026 .tosec = { ALL_INIT_SECTIONS, NULL },
1027 .mismatch = ANY_EXIT_TO_ANY_INIT,
1028 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1029},
1030/* Do not export init/exit functions or data */
1031{
1032 .fromsec = { "__ksymtab*", NULL },
1033 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1034 .mismatch = EXPORT_TO_INIT_EXIT,
1035 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1036}
1037};
1038
1039static const struct sectioncheck *section_mismatch(
1040 const char *fromsec, const char *tosec)
1041{
1042 int i;
1043 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1044 const struct sectioncheck *check = §ioncheck[0];
1045
1046 for (i = 0; i < elems; i++) {
1047 if (match(fromsec, check->fromsec) &&
1048 match(tosec, check->tosec))
1049 return check;
1050 check++;
1051 }
1052 return NULL;
1053}
1054
1055/**
1056 * Whitelist to allow certain references to pass with no warning.
1057 *
1058 * Pattern 1:
1059 * If a module parameter is declared __initdata and permissions=0
1060 * then this is legal despite the warning generated.
1061 * We cannot see value of permissions here, so just ignore
1062 * this pattern.
1063 * The pattern is identified by:
1064 * tosec = .init.data
1065 * fromsec = .data*
1066 * atsym =__param*
1067 *
1068 * Pattern 1a:
1069 * module_param_call() ops can refer to __init set function if permissions=0
1070 * The pattern is identified by:
1071 * tosec = .init.text
1072 * fromsec = .data*
1073 * atsym = __param_ops_*
1074 *
1075 * Pattern 2:
1076 * Many drivers utilise a *driver container with references to
1077 * add, remove, probe functions etc.
1078 * These functions may often be marked __devinit and we do not want to
1079 * warn here.
1080 * the pattern is identified by:
1081 * tosec = init or exit section
1082 * fromsec = data section
1083 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1084 * *probe_one, *_console, *_timer
1085 *
1086 * Pattern 3:
1087 * Whitelist all references from .head.text to any init section
1088 *
1089 * Pattern 4:
1090 * Some symbols belong to init section but still it is ok to reference
1091 * these from non-init sections as these symbols don't have any memory
1092 * allocated for them and symbol address and value are same. So even
1093 * if init section is freed, its ok to reference those symbols.
1094 * For ex. symbols marking the init section boundaries.
1095 * This pattern is identified by
1096 * refsymname = __init_begin, _sinittext, _einittext
1097 *
1098 **/
1099static int secref_whitelist(const struct sectioncheck *mismatch,
1100 const char *fromsec, const char *fromsym,
1101 const char *tosec, const char *tosym)
1102{
1103 /* Check for pattern 1 */
1104 if (match(tosec, init_data_sections) &&
1105 match(fromsec, data_sections) &&
1106 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1107 return 0;
1108
1109 /* Check for pattern 1a */
1110 if (strcmp(tosec, ".init.text") == 0 &&
1111 match(fromsec, data_sections) &&
1112 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1113 return 0;
1114
1115 /* Check for pattern 2 */
1116 if (match(tosec, init_exit_sections) &&
1117 match(fromsec, data_sections) &&
1118 match(fromsym, mismatch->symbol_white_list))
1119 return 0;
1120
1121 /* Check for pattern 3 */
1122 if (match(fromsec, head_sections) &&
1123 match(tosec, init_sections))
1124 return 0;
1125
1126 /* Check for pattern 4 */
1127 if (match(tosym, linker_symbols))
1128 return 0;
1129
1130 return 1;
1131}
1132
1133/**
1134 * Find symbol based on relocation record info.
1135 * In some cases the symbol supplied is a valid symbol so
1136 * return refsym. If st_name != 0 we assume this is a valid symbol.
1137 * In other cases the symbol needs to be looked up in the symbol table
1138 * based on section and address.
1139 * **/
1140static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1141 Elf_Sym *relsym)
1142{
1143 Elf_Sym *sym;
1144 Elf_Sym *near = NULL;
1145 Elf64_Sword distance = 20;
1146 Elf64_Sword d;
1147 unsigned int relsym_secindex;
1148
1149 if (relsym->st_name != 0)
1150 return relsym;
1151
1152 relsym_secindex = get_secindex(elf, relsym);
1153 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1154 if (get_secindex(elf, sym) != relsym_secindex)
1155 continue;
1156 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1157 continue;
1158 if (sym->st_value == addr)
1159 return sym;
1160 /* Find a symbol nearby - addr are maybe negative */
1161 d = sym->st_value - addr;
1162 if (d < 0)
1163 d = addr - sym->st_value;
1164 if (d < distance) {
1165 distance = d;
1166 near = sym;
1167 }
1168 }
1169 /* We need a close match */
1170 if (distance < 20)
1171 return near;
1172 else
1173 return NULL;
1174}
1175
1176static inline int is_arm_mapping_symbol(const char *str)
1177{
1178 return str[0] == '$' && strchr("atd", str[1])
1179 && (str[2] == '\0' || str[2] == '.');
1180}
1181
1182/*
1183 * If there's no name there, ignore it; likewise, ignore it if it's
1184 * one of the magic symbols emitted used by current ARM tools.
1185 *
1186 * Otherwise if find_symbols_between() returns those symbols, they'll
1187 * fail the whitelist tests and cause lots of false alarms ... fixable
1188 * only by merging __exit and __init sections into __text, bloating
1189 * the kernel (which is especially evil on embedded platforms).
1190 */
1191static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1192{
1193 const char *name = elf->strtab + sym->st_name;
1194
1195 if (!name || !strlen(name))
1196 return 0;
1197 return !is_arm_mapping_symbol(name);
1198}
1199
1200/*
1201 * Find symbols before or equal addr and after addr - in the section sec.
1202 * If we find two symbols with equal offset prefer one with a valid name.
1203 * The ELF format may have a better way to detect what type of symbol
1204 * it is, but this works for now.
1205 **/
1206static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1207 const char *sec)
1208{
1209 Elf_Sym *sym;
1210 Elf_Sym *near = NULL;
1211 Elf_Addr distance = ~0;
1212
1213 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1214 const char *symsec;
1215
1216 if (is_shndx_special(sym->st_shndx))
1217 continue;
1218 symsec = sec_name(elf, get_secindex(elf, sym));
1219 if (strcmp(symsec, sec) != 0)
1220 continue;
1221 if (!is_valid_name(elf, sym))
1222 continue;
1223 if (sym->st_value <= addr) {
1224 if ((addr - sym->st_value) < distance) {
1225 distance = addr - sym->st_value;
1226 near = sym;
1227 } else if ((addr - sym->st_value) == distance) {
1228 near = sym;
1229 }
1230 }
1231 }
1232 return near;
1233}
1234
1235/*
1236 * Convert a section name to the function/data attribute
1237 * .init.text => __init
1238 * .cpuinit.data => __cpudata
1239 * .memexitconst => __memconst
1240 * etc.
1241 *
1242 * The memory of returned value has been allocated on a heap. The user of this
1243 * method should free it after usage.
1244*/
1245static char *sec2annotation(const char *s)
1246{
1247 if (match(s, init_exit_sections)) {
1248 char *p = malloc(20);
1249 char *r = p;
1250
1251 *p++ = '_';
1252 *p++ = '_';
1253 if (*s == '.')
1254 s++;
1255 while (*s && *s != '.')
1256 *p++ = *s++;
1257 *p = '\0';
1258 if (*s == '.')
1259 s++;
1260 if (strstr(s, "rodata") != NULL)
1261 strcat(p, "const ");
1262 else if (strstr(s, "data") != NULL)
1263 strcat(p, "data ");
1264 else
1265 strcat(p, " ");
1266 return r;
1267 } else {
1268 return strdup("");
1269 }
1270}
1271
1272static int is_function(Elf_Sym *sym)
1273{
1274 if (sym)
1275 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1276 else
1277 return -1;
1278}
1279
1280static void print_section_list(const char * const list[20])
1281{
1282 const char *const *s = list;
1283
1284 while (*s) {
1285 fprintf(stderr, "%s", *s);
1286 s++;
1287 if (*s)
1288 fprintf(stderr, ", ");
1289 }
1290 fprintf(stderr, "\n");
1291}
1292
1293/*
1294 * Print a warning about a section mismatch.
1295 * Try to find symbols near it so user can find it.
1296 * Check whitelist before warning - it may be a false positive.
1297 */
1298static void report_sec_mismatch(const char *modname,
1299 const struct sectioncheck *mismatch,
1300 const char *fromsec,
1301 unsigned long long fromaddr,
1302 const char *fromsym,
1303 int from_is_func,
1304 const char *tosec, const char *tosym,
1305 int to_is_func)
1306{
1307 const char *from, *from_p;
1308 const char *to, *to_p;
1309 char *prl_from;
1310 char *prl_to;
1311
1312 switch (from_is_func) {
1313 case 0: from = "variable"; from_p = ""; break;
1314 case 1: from = "function"; from_p = "()"; break;
1315 default: from = "(unknown reference)"; from_p = ""; break;
1316 }
1317 switch (to_is_func) {
1318 case 0: to = "variable"; to_p = ""; break;
1319 case 1: to = "function"; to_p = "()"; break;
1320 default: to = "(unknown reference)"; to_p = ""; break;
1321 }
1322
1323 sec_mismatch_count++;
1324 if (!sec_mismatch_verbose)
1325 return;
1326
1327 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1328 "to the %s %s:%s%s\n",
1329 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1330 tosym, to_p);
1331
1332 switch (mismatch->mismatch) {
1333 case TEXT_TO_ANY_INIT:
1334 prl_from = sec2annotation(fromsec);
1335 prl_to = sec2annotation(tosec);
1336 fprintf(stderr,
1337 "The function %s%s() references\n"
1338 "the %s %s%s%s.\n"
1339 "This is often because %s lacks a %s\n"
1340 "annotation or the annotation of %s is wrong.\n",
1341 prl_from, fromsym,
1342 to, prl_to, tosym, to_p,
1343 fromsym, prl_to, tosym);
1344 free(prl_from);
1345 free(prl_to);
1346 break;
1347 case DATA_TO_ANY_INIT: {
1348 prl_to = sec2annotation(tosec);
1349 fprintf(stderr,
1350 "The variable %s references\n"
1351 "the %s %s%s%s\n"
1352 "If the reference is valid then annotate the\n"
1353 "variable with __init* or __refdata (see linux/init.h) "
1354 "or name the variable:\n",
1355 fromsym, to, prl_to, tosym, to_p);
1356 print_section_list(mismatch->symbol_white_list);
1357 free(prl_to);
1358 break;
1359 }
1360 case TEXT_TO_ANY_EXIT:
1361 prl_to = sec2annotation(tosec);
1362 fprintf(stderr,
1363 "The function %s() references a %s in an exit section.\n"
1364 "Often the %s %s%s has valid usage outside the exit section\n"
1365 "and the fix is to remove the %sannotation of %s.\n",
1366 fromsym, to, to, tosym, to_p, prl_to, tosym);
1367 free(prl_to);
1368 break;
1369 case DATA_TO_ANY_EXIT: {
1370 prl_to = sec2annotation(tosec);
1371 fprintf(stderr,
1372 "The variable %s references\n"
1373 "the %s %s%s%s\n"
1374 "If the reference is valid then annotate the\n"
1375 "variable with __exit* (see linux/init.h) or "
1376 "name the variable:\n",
1377 fromsym, to, prl_to, tosym, to_p);
1378 print_section_list(mismatch->symbol_white_list);
1379 free(prl_to);
1380 break;
1381 }
1382 case XXXINIT_TO_SOME_INIT:
1383 case XXXEXIT_TO_SOME_EXIT:
1384 prl_from = sec2annotation(fromsec);
1385 prl_to = sec2annotation(tosec);
1386 fprintf(stderr,
1387 "The %s %s%s%s references\n"
1388 "a %s %s%s%s.\n"
1389 "If %s is only used by %s then\n"
1390 "annotate %s with a matching annotation.\n",
1391 from, prl_from, fromsym, from_p,
1392 to, prl_to, tosym, to_p,
1393 tosym, fromsym, tosym);
1394 free(prl_from);
1395 free(prl_to);
1396 break;
1397 case ANY_INIT_TO_ANY_EXIT:
1398 prl_from = sec2annotation(fromsec);
1399 prl_to = sec2annotation(tosec);
1400 fprintf(stderr,
1401 "The %s %s%s%s references\n"
1402 "a %s %s%s%s.\n"
1403 "This is often seen when error handling "
1404 "in the init function\n"
1405 "uses functionality in the exit path.\n"
1406 "The fix is often to remove the %sannotation of\n"
1407 "%s%s so it may be used outside an exit section.\n",
1408 from, prl_from, fromsym, from_p,
1409 to, prl_to, tosym, to_p,
1410 prl_to, tosym, to_p);
1411 free(prl_from);
1412 free(prl_to);
1413 break;
1414 case ANY_EXIT_TO_ANY_INIT:
1415 prl_from = sec2annotation(fromsec);
1416 prl_to = sec2annotation(tosec);
1417 fprintf(stderr,
1418 "The %s %s%s%s references\n"
1419 "a %s %s%s%s.\n"
1420 "This is often seen when error handling "
1421 "in the exit function\n"
1422 "uses functionality in the init path.\n"
1423 "The fix is often to remove the %sannotation of\n"
1424 "%s%s so it may be used outside an init section.\n",
1425 from, prl_from, fromsym, from_p,
1426 to, prl_to, tosym, to_p,
1427 prl_to, tosym, to_p);
1428 free(prl_from);
1429 free(prl_to);
1430 break;
1431 case EXPORT_TO_INIT_EXIT:
1432 prl_to = sec2annotation(tosec);
1433 fprintf(stderr,
1434 "The symbol %s is exported and annotated %s\n"
1435 "Fix this by removing the %sannotation of %s "
1436 "or drop the export.\n",
1437 tosym, prl_to, prl_to, tosym);
1438 free(prl_to);
1439 break;
1440 }
1441 fprintf(stderr, "\n");
1442}
1443
1444static void check_section_mismatch(const char *modname, struct elf_info *elf,
1445 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1446{
1447 const char *tosec;
1448 const struct sectioncheck *mismatch;
1449
1450 tosec = sec_name(elf, get_secindex(elf, sym));
1451 mismatch = section_mismatch(fromsec, tosec);
1452 if (mismatch) {
1453 Elf_Sym *to;
1454 Elf_Sym *from;
1455 const char *tosym;
1456 const char *fromsym;
1457
1458 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1459 fromsym = sym_name(elf, from);
1460 to = find_elf_symbol(elf, r->r_addend, sym);
1461 tosym = sym_name(elf, to);
1462
1463 /* check whitelist - we may ignore it */
1464 if (secref_whitelist(mismatch,
1465 fromsec, fromsym, tosec, tosym)) {
1466 report_sec_mismatch(modname, mismatch,
1467 fromsec, r->r_offset, fromsym,
1468 is_function(from), tosec, tosym,
1469 is_function(to));
1470 }
1471 }
1472}
1473
1474static unsigned int *reloc_location(struct elf_info *elf,
1475 Elf_Shdr *sechdr, Elf_Rela *r)
1476{
1477 Elf_Shdr *sechdrs = elf->sechdrs;
1478 int section = sechdr->sh_info;
1479
1480 return (void *)elf->hdr + sechdrs[section].sh_offset +
1481 r->r_offset;
1482}
1483
1484static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1485{
1486 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1487 unsigned int *location = reloc_location(elf, sechdr, r);
1488
1489 switch (r_typ) {
1490 case R_386_32:
1491 r->r_addend = TO_NATIVE(*location);
1492 break;
1493 case R_386_PC32:
1494 r->r_addend = TO_NATIVE(*location) + 4;
1495 /* For CONFIG_RELOCATABLE=y */
1496 if (elf->hdr->e_type == ET_EXEC)
1497 r->r_addend += r->r_offset;
1498 break;
1499 }
1500 return 0;
1501}
1502
1503#ifndef R_ARM_CALL
1504#define R_ARM_CALL 28
1505#endif
1506#ifndef R_ARM_JUMP24
1507#define R_ARM_JUMP24 29
1508#endif
1509
1510static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1511{
1512 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1513
1514 switch (r_typ) {
1515 case R_ARM_ABS32:
1516 /* From ARM ABI: (S + A) | T */
1517 r->r_addend = (int)(long)
1518 (elf->symtab_start + ELF_R_SYM(r->r_info));
1519 break;
1520 case R_ARM_PC24:
1521 case R_ARM_CALL:
1522 case R_ARM_JUMP24:
1523 /* From ARM ABI: ((S + A) | T) - P */
1524 r->r_addend = (int)(long)(elf->hdr +
1525 sechdr->sh_offset +
1526 (r->r_offset - sechdr->sh_addr));
1527 break;
1528 default:
1529 return 1;
1530 }
1531 return 0;
1532}
1533
1534static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1535{
1536 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1537 unsigned int *location = reloc_location(elf, sechdr, r);
1538 unsigned int inst;
1539
1540 if (r_typ == R_MIPS_HI16)
1541 return 1; /* skip this */
1542 inst = TO_NATIVE(*location);
1543 switch (r_typ) {
1544 case R_MIPS_LO16:
1545 r->r_addend = inst & 0xffff;
1546 break;
1547 case R_MIPS_26:
1548 r->r_addend = (inst & 0x03ffffff) << 2;
1549 break;
1550 case R_MIPS_32:
1551 r->r_addend = inst;
1552 break;
1553 }
1554 return 0;
1555}
1556
1557static void section_rela(const char *modname, struct elf_info *elf,
1558 Elf_Shdr *sechdr)
1559{
1560 Elf_Sym *sym;
1561 Elf_Rela *rela;
1562 Elf_Rela r;
1563 unsigned int r_sym;
1564 const char *fromsec;
1565
1566 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1567 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1568
1569 fromsec = sech_name(elf, sechdr);
1570 fromsec += strlen(".rela");
1571 /* if from section (name) is know good then skip it */
1572 if (match(fromsec, section_white_list))
1573 return;
1574
1575 for (rela = start; rela < stop; rela++) {
1576 r.r_offset = TO_NATIVE(rela->r_offset);
1577#if KERNEL_ELFCLASS == ELFCLASS64
1578 if (elf->hdr->e_machine == EM_MIPS) {
1579 unsigned int r_typ;
1580 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1581 r_sym = TO_NATIVE(r_sym);
1582 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1583 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1584 } else {
1585 r.r_info = TO_NATIVE(rela->r_info);
1586 r_sym = ELF_R_SYM(r.r_info);
1587 }
1588#else
1589 r.r_info = TO_NATIVE(rela->r_info);
1590 r_sym = ELF_R_SYM(r.r_info);
1591#endif
1592 r.r_addend = TO_NATIVE(rela->r_addend);
1593 sym = elf->symtab_start + r_sym;
1594 /* Skip special sections */
1595 if (is_shndx_special(sym->st_shndx))
1596 continue;
1597 check_section_mismatch(modname, elf, &r, sym, fromsec);
1598 }
1599}
1600
1601static void section_rel(const char *modname, struct elf_info *elf,
1602 Elf_Shdr *sechdr)
1603{
1604 Elf_Sym *sym;
1605 Elf_Rel *rel;
1606 Elf_Rela r;
1607 unsigned int r_sym;
1608 const char *fromsec;
1609
1610 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1611 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1612
1613 fromsec = sech_name(elf, sechdr);
1614 fromsec += strlen(".rel");
1615 /* if from section (name) is know good then skip it */
1616 if (match(fromsec, section_white_list))
1617 return;
1618
1619 for (rel = start; rel < stop; rel++) {
1620 r.r_offset = TO_NATIVE(rel->r_offset);
1621#if KERNEL_ELFCLASS == ELFCLASS64
1622 if (elf->hdr->e_machine == EM_MIPS) {
1623 unsigned int r_typ;
1624 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1625 r_sym = TO_NATIVE(r_sym);
1626 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1627 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1628 } else {
1629 r.r_info = TO_NATIVE(rel->r_info);
1630 r_sym = ELF_R_SYM(r.r_info);
1631 }
1632#else
1633 r.r_info = TO_NATIVE(rel->r_info);
1634 r_sym = ELF_R_SYM(r.r_info);
1635#endif
1636 r.r_addend = 0;
1637 switch (elf->hdr->e_machine) {
1638 case EM_386:
1639 if (addend_386_rel(elf, sechdr, &r))
1640 continue;
1641 break;
1642 case EM_ARM:
1643 if (addend_arm_rel(elf, sechdr, &r))
1644 continue;
1645 break;
1646 case EM_MIPS:
1647 if (addend_mips_rel(elf, sechdr, &r))
1648 continue;
1649 break;
1650 }
1651 sym = elf->symtab_start + r_sym;
1652 /* Skip special sections */
1653 if (is_shndx_special(sym->st_shndx))
1654 continue;
1655 check_section_mismatch(modname, elf, &r, sym, fromsec);
1656 }
1657}
1658
1659/**
1660 * A module includes a number of sections that are discarded
1661 * either when loaded or when used as built-in.
1662 * For loaded modules all functions marked __init and all data
1663 * marked __initdata will be discarded when the module has been initialized.
1664 * Likewise for modules used built-in the sections marked __exit
1665 * are discarded because __exit marked function are supposed to be called
1666 * only when a module is unloaded which never happens for built-in modules.
1667 * The check_sec_ref() function traverses all relocation records
1668 * to find all references to a section that reference a section that will
1669 * be discarded and warns about it.
1670 **/
1671static void check_sec_ref(struct module *mod, const char *modname,
1672 struct elf_info *elf)
1673{
1674 int i;
1675 Elf_Shdr *sechdrs = elf->sechdrs;
1676
1677 /* Walk through all sections */
1678 for (i = 0; i < elf->num_sections; i++) {
1679 check_section(modname, elf, &elf->sechdrs[i]);
1680 /* We want to process only relocation sections and not .init */
1681 if (sechdrs[i].sh_type == SHT_RELA)
1682 section_rela(modname, elf, &elf->sechdrs[i]);
1683 else if (sechdrs[i].sh_type == SHT_REL)
1684 section_rel(modname, elf, &elf->sechdrs[i]);
1685 }
1686}
1687
1688static void read_symbols(char *modname)
1689{
1690 const char *symname;
1691 char *version;
1692 char *license;
1693 struct module *mod;
1694 struct elf_info info = { };
1695 Elf_Sym *sym;
1696
1697 if (!parse_elf(&info, modname))
1698 return;
1699
1700 mod = new_module(modname);
1701
1702 /* When there's no vmlinux, don't print warnings about
1703 * unresolved symbols (since there'll be too many ;) */
1704 if (is_vmlinux(modname)) {
1705 have_vmlinux = 1;
1706 mod->skip = 1;
1707 }
1708
1709 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1710 if (info.modinfo && !license && !is_vmlinux(modname))
1711 warn("modpost: missing MODULE_LICENSE() in %s\n"
1712 "see include/linux/module.h for "
1713 "more information\n", modname);
1714 while (license) {
1715 if (license_is_gpl_compatible(license))
1716 mod->gpl_compatible = 1;
1717 else {
1718 mod->gpl_compatible = 0;
1719 break;
1720 }
1721 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1722 "license", license);
1723 }
1724
1725 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1726 symname = info.strtab + sym->st_name;
1727
1728 handle_modversions(mod, &info, sym, symname);
1729 handle_moddevtable(mod, &info, sym, symname);
1730 }
1731 if (!is_vmlinux(modname) ||
1732 (is_vmlinux(modname) && vmlinux_section_warnings))
1733 check_sec_ref(mod, modname, &info);
1734
1735 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1736 if (version)
1737 maybe_frob_rcs_version(modname, version, info.modinfo,
1738 version - (char *)info.hdr);
1739 if (version || (all_versions && !is_vmlinux(modname)))
1740 get_src_version(modname, mod->srcversion,
1741 sizeof(mod->srcversion)-1);
1742
1743 parse_elf_finish(&info);
1744
1745 /* Our trick to get versioning for module struct etc. - it's
1746 * never passed as an argument to an exported function, so
1747 * the automatic versioning doesn't pick it up, but it's really
1748 * important anyhow */
1749 if (modversions)
1750 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1751}
1752
1753#define SZ 500
1754
1755/* We first write the generated file into memory using the
1756 * following helper, then compare to the file on disk and
1757 * only update the later if anything changed */
1758
1759void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1760 const char *fmt, ...)
1761{
1762 char tmp[SZ];
1763 int len;
1764 va_list ap;
1765
1766 va_start(ap, fmt);
1767 len = vsnprintf(tmp, SZ, fmt, ap);
1768 buf_write(buf, tmp, len);
1769 va_end(ap);
1770}
1771
1772void buf_write(struct buffer *buf, const char *s, int len)
1773{
1774 if (buf->size - buf->pos < len) {
1775 buf->size += len + SZ;
1776 buf->p = realloc(buf->p, buf->size);
1777 }
1778 strncpy(buf->p + buf->pos, s, len);
1779 buf->pos += len;
1780}
1781
1782static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1783{
1784 const char *e = is_vmlinux(m) ?"":".ko";
1785
1786 switch (exp) {
1787 case export_gpl:
1788 fatal("modpost: GPL-incompatible module %s%s "
1789 "uses GPL-only symbol '%s'\n", m, e, s);
1790 break;
1791 case export_unused_gpl:
1792 fatal("modpost: GPL-incompatible module %s%s "
1793 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1794 break;
1795 case export_gpl_future:
1796 warn("modpost: GPL-incompatible module %s%s "
1797 "uses future GPL-only symbol '%s'\n", m, e, s);
1798 break;
1799 case export_plain:
1800 case export_unused:
1801 case export_unknown:
1802 /* ignore */
1803 break;
1804 }
1805}
1806
1807static void check_for_unused(enum export exp, const char *m, const char *s)
1808{
1809 const char *e = is_vmlinux(m) ?"":".ko";
1810
1811 switch (exp) {
1812 case export_unused:
1813 case export_unused_gpl:
1814 warn("modpost: module %s%s "
1815 "uses symbol '%s' marked UNUSED\n", m, e, s);
1816 break;
1817 default:
1818 /* ignore */
1819 break;
1820 }
1821}
1822
1823static void check_exports(struct module *mod)
1824{
1825 struct symbol *s, *exp;
1826
1827 for (s = mod->unres; s; s = s->next) {
1828 const char *basename;
1829 exp = find_symbol(s->name);
1830 if (!exp || exp->module == mod)
1831 continue;
1832 basename = strrchr(mod->name, '/');
1833 if (basename)
1834 basename++;
1835 else
1836 basename = mod->name;
1837 if (!mod->gpl_compatible)
1838 check_for_gpl_usage(exp->export, basename, exp->name);
1839 check_for_unused(exp->export, basename, exp->name);
1840 }
1841}
1842
1843/**
1844 * Header for the generated file
1845 **/
1846static void add_header(struct buffer *b, struct module *mod)
1847{
1848 buf_printf(b, "#include <linux/module.h>\n");
1849 buf_printf(b, "#include <linux/vermagic.h>\n");
1850 buf_printf(b, "#include <linux/compiler.h>\n");
1851 buf_printf(b, "\n");
1852 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1853 buf_printf(b, "\n");
1854 buf_printf(b, "struct module __this_module\n");
1855 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1856 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1857 if (mod->has_init)
1858 buf_printf(b, "\t.init = init_module,\n");
1859 if (mod->has_cleanup)
1860 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1861 "\t.exit = cleanup_module,\n"
1862 "#endif\n");
1863 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1864 buf_printf(b, "};\n");
1865}
1866
1867static void add_intree_flag(struct buffer *b, int is_intree)
1868{
1869 if (is_intree)
1870 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1871}
1872
1873static void add_staging_flag(struct buffer *b, const char *name)
1874{
1875 static const char *staging_dir = "drivers/staging";
1876
1877 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1878 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1879}
1880
1881/**
1882 * Record CRCs for unresolved symbols
1883 **/
1884static int add_versions(struct buffer *b, struct module *mod)
1885{
1886 struct symbol *s, *exp;
1887 int err = 0;
1888
1889 for (s = mod->unres; s; s = s->next) {
1890 exp = find_symbol(s->name);
1891 if (!exp || exp->module == mod) {
1892 if (have_vmlinux && !s->weak) {
1893 if (warn_unresolved) {
1894 warn("\"%s\" [%s.ko] undefined!\n",
1895 s->name, mod->name);
1896 } else {
1897 merror("\"%s\" [%s.ko] undefined!\n",
1898 s->name, mod->name);
1899 err = 1;
1900 }
1901 }
1902 continue;
1903 }
1904 s->module = exp->module;
1905 s->crc_valid = exp->crc_valid;
1906 s->crc = exp->crc;
1907 }
1908
1909 if (!modversions)
1910 return err;
1911
1912 buf_printf(b, "\n");
1913 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1914 buf_printf(b, "__used\n");
1915 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1916
1917 for (s = mod->unres; s; s = s->next) {
1918 if (!s->module)
1919 continue;
1920 if (!s->crc_valid) {
1921 warn("\"%s\" [%s.ko] has no CRC!\n",
1922 s->name, mod->name);
1923 continue;
1924 }
1925 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1926 }
1927
1928 buf_printf(b, "};\n");
1929
1930 return err;
1931}
1932
1933static void add_depends(struct buffer *b, struct module *mod,
1934 struct module *modules)
1935{
1936 struct symbol *s;
1937 struct module *m;
1938 int first = 1;
1939
1940 for (m = modules; m; m = m->next)
1941 m->seen = is_vmlinux(m->name);
1942
1943 buf_printf(b, "\n");
1944 buf_printf(b, "static const char __module_depends[]\n");
1945 buf_printf(b, "__used\n");
1946 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1947 buf_printf(b, "\"depends=");
1948 for (s = mod->unres; s; s = s->next) {
1949 const char *p;
1950 if (!s->module)
1951 continue;
1952
1953 if (s->module->seen)
1954 continue;
1955
1956 s->module->seen = 1;
1957 p = strrchr(s->module->name, '/');
1958 if (p)
1959 p++;
1960 else
1961 p = s->module->name;
1962 buf_printf(b, "%s%s", first ? "" : ",", p);
1963 first = 0;
1964 }
1965 buf_printf(b, "\";\n");
1966}
1967
1968static void add_srcversion(struct buffer *b, struct module *mod)
1969{
1970 if (mod->srcversion[0]) {
1971 buf_printf(b, "\n");
1972 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1973 mod->srcversion);
1974 }
1975}
1976
1977static void write_if_changed(struct buffer *b, const char *fname)
1978{
1979 char *tmp;
1980 FILE *file;
1981 struct stat st;
1982
1983 file = fopen(fname, "r");
1984 if (!file)
1985 goto write;
1986
1987 if (fstat(fileno(file), &st) < 0)
1988 goto close_write;
1989
1990 if (st.st_size != b->pos)
1991 goto close_write;
1992
1993 tmp = NOFAIL(malloc(b->pos));
1994 if (fread(tmp, 1, b->pos, file) != b->pos)
1995 goto free_write;
1996
1997 if (memcmp(tmp, b->p, b->pos) != 0)
1998 goto free_write;
1999
2000 free(tmp);
2001 fclose(file);
2002 return;
2003
2004 free_write:
2005 free(tmp);
2006 close_write:
2007 fclose(file);
2008 write:
2009 file = fopen(fname, "w");
2010 if (!file) {
2011 perror(fname);
2012 exit(1);
2013 }
2014 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2015 perror(fname);
2016 exit(1);
2017 }
2018 fclose(file);
2019}
2020
2021/* parse Module.symvers file. line format:
2022 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2023 **/
2024static void read_dump(const char *fname, unsigned int kernel)
2025{
2026 unsigned long size, pos = 0;
2027 void *file = grab_file(fname, &size);
2028 char *line;
2029
2030 if (!file)
2031 /* No symbol versions, silently ignore */
2032 return;
2033
2034 while ((line = get_next_line(&pos, file, size))) {
2035 char *symname, *modname, *d, *export, *end;
2036 unsigned int crc;
2037 struct module *mod;
2038 struct symbol *s;
2039
2040 if (!(symname = strchr(line, '\t')))
2041 goto fail;
2042 *symname++ = '\0';
2043 if (!(modname = strchr(symname, '\t')))
2044 goto fail;
2045 *modname++ = '\0';
2046 if ((export = strchr(modname, '\t')) != NULL)
2047 *export++ = '\0';
2048 if (export && ((end = strchr(export, '\t')) != NULL))
2049 *end = '\0';
2050 crc = strtoul(line, &d, 16);
2051 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2052 goto fail;
2053 mod = find_module(modname);
2054 if (!mod) {
2055 if (is_vmlinux(modname))
2056 have_vmlinux = 1;
2057 mod = new_module(modname);
2058 mod->skip = 1;
2059 }
2060 s = sym_add_exported(symname, mod, export_no(export));
2061 s->kernel = kernel;
2062 s->preloaded = 1;
2063 sym_update_crc(symname, mod, crc, export_no(export));
2064 }
2065 return;
2066fail:
2067 fatal("parse error in symbol dump file\n");
2068}
2069
2070/* For normal builds always dump all symbols.
2071 * For external modules only dump symbols
2072 * that are not read from kernel Module.symvers.
2073 **/
2074static int dump_sym(struct symbol *sym)
2075{
2076 if (!external_module)
2077 return 1;
2078 if (sym->vmlinux || sym->kernel)
2079 return 0;
2080 return 1;
2081}
2082
2083static void write_dump(const char *fname)
2084{
2085 struct buffer buf = { };
2086 struct symbol *symbol;
2087 int n;
2088
2089 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2090 symbol = symbolhash[n];
2091 while (symbol) {
2092 if (dump_sym(symbol))
2093 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2094 symbol->crc, symbol->name,
2095 symbol->module->name,
2096 export_str(symbol->export));
2097 symbol = symbol->next;
2098 }
2099 }
2100 write_if_changed(&buf, fname);
2101}
2102
2103struct ext_sym_list {
2104 struct ext_sym_list *next;
2105 const char *file;
2106};
2107
2108int main(int argc, char **argv)
2109{
2110 struct module *mod;
2111 struct buffer buf = { };
2112 char *kernel_read = NULL, *module_read = NULL;
2113 char *dump_write = NULL;
2114 int opt;
2115 int err;
2116 struct ext_sym_list *extsym_iter;
2117 struct ext_sym_list *extsym_start = NULL;
2118
2119 while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2120 switch (opt) {
2121 case 'i':
2122 kernel_read = optarg;
2123 break;
2124 case 'I':
2125 module_read = optarg;
2126 external_module = 1;
2127 break;
2128 case 'c':
2129 cross_build = 1;
2130 break;
2131 case 'e':
2132 external_module = 1;
2133 extsym_iter =
2134 NOFAIL(malloc(sizeof(*extsym_iter)));
2135 extsym_iter->next = extsym_start;
2136 extsym_iter->file = optarg;
2137 extsym_start = extsym_iter;
2138 break;
2139 case 'm':
2140 modversions = 1;
2141 break;
2142 case 'o':
2143 dump_write = optarg;
2144 break;
2145 case 'a':
2146 all_versions = 1;
2147 break;
2148 case 's':
2149 vmlinux_section_warnings = 0;
2150 break;
2151 case 'S':
2152 sec_mismatch_verbose = 0;
2153 break;
2154 case 'w':
2155 warn_unresolved = 1;
2156 break;
2157 default:
2158 exit(1);
2159 }
2160 }
2161
2162 if (kernel_read)
2163 read_dump(kernel_read, 1);
2164 if (module_read)
2165 read_dump(module_read, 0);
2166 while (extsym_start) {
2167 read_dump(extsym_start->file, 0);
2168 extsym_iter = extsym_start->next;
2169 free(extsym_start);
2170 extsym_start = extsym_iter;
2171 }
2172
2173 while (optind < argc)
2174 read_symbols(argv[optind++]);
2175
2176 for (mod = modules; mod; mod = mod->next) {
2177 if (mod->skip)
2178 continue;
2179 check_exports(mod);
2180 }
2181
2182 err = 0;
2183
2184 for (mod = modules; mod; mod = mod->next) {
2185 char fname[strlen(mod->name) + 10];
2186
2187 if (mod->skip)
2188 continue;
2189
2190 buf.pos = 0;
2191
2192 add_header(&buf, mod);
2193 add_intree_flag(&buf, !external_module);
2194 add_staging_flag(&buf, mod->name);
2195 err |= add_versions(&buf, mod);
2196 add_depends(&buf, mod, modules);
2197 add_moddevtable(&buf, mod);
2198 add_srcversion(&buf, mod);
2199
2200 sprintf(fname, "%s.mod.c", mod->name);
2201 write_if_changed(&buf, fname);
2202 }
2203
2204 if (dump_write)
2205 write_dump(dump_write);
2206 if (sec_mismatch_count && !sec_mismatch_verbose)
2207 warn("modpost: Found %d section mismatch(es).\n"
2208 "To see full details build your kernel with:\n"
2209 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2210 sec_mismatch_count);
2211
2212 return err;
2213}