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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 <stdio.h>
16#include <ctype.h>
17#include <string.h>
18#include <limits.h>
19#include <stdbool.h>
20#include <errno.h>
21#include "modpost.h"
22#include "../../include/linux/license.h"
23
24/* Are we using CONFIG_MODVERSIONS? */
25static int modversions = 0;
26/* Warn about undefined symbols? (do so if we have vmlinux) */
27static int have_vmlinux = 0;
28/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
29static int all_versions = 0;
30/* If we are modposting external module set to 1 */
31static int external_module = 0;
32/* Warn about section mismatch in vmlinux if set to 1 */
33static int vmlinux_section_warnings = 1;
34/* Only warn about unresolved symbols */
35static int warn_unresolved = 0;
36/* How a symbol is exported */
37static int sec_mismatch_count = 0;
38static int sec_mismatch_fatal = 0;
39/* ignore missing files */
40static int ignore_missing_files;
41/* write namespace dependencies */
42static int write_namespace_deps;
43
44enum export {
45 export_plain, export_unused, export_gpl,
46 export_unused_gpl, export_gpl_future, export_unknown
47};
48
49/* In kernel, this size is defined in linux/module.h;
50 * here we use Elf_Addr instead of long for covering cross-compile
51 */
52
53#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
54
55#define PRINTF __attribute__ ((format (printf, 1, 2)))
56
57PRINTF void fatal(const char *fmt, ...)
58{
59 va_list arglist;
60
61 fprintf(stderr, "FATAL: ");
62
63 va_start(arglist, fmt);
64 vfprintf(stderr, fmt, arglist);
65 va_end(arglist);
66
67 exit(1);
68}
69
70PRINTF void warn(const char *fmt, ...)
71{
72 va_list arglist;
73
74 fprintf(stderr, "WARNING: ");
75
76 va_start(arglist, fmt);
77 vfprintf(stderr, fmt, arglist);
78 va_end(arglist);
79}
80
81PRINTF void merror(const char *fmt, ...)
82{
83 va_list arglist;
84
85 fprintf(stderr, "ERROR: ");
86
87 va_start(arglist, fmt);
88 vfprintf(stderr, fmt, arglist);
89 va_end(arglist);
90}
91
92static inline bool strends(const char *str, const char *postfix)
93{
94 if (strlen(str) < strlen(postfix))
95 return false;
96
97 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
98}
99
100static int is_vmlinux(const char *modname)
101{
102 const char *myname;
103
104 myname = strrchr(modname, '/');
105 if (myname)
106 myname++;
107 else
108 myname = modname;
109
110 return (strcmp(myname, "vmlinux") == 0) ||
111 (strcmp(myname, "vmlinux.o") == 0);
112}
113
114void *do_nofail(void *ptr, const char *expr)
115{
116 if (!ptr)
117 fatal("modpost: Memory allocation failure: %s.\n", expr);
118
119 return ptr;
120}
121
122/* A list of all modules we processed */
123static struct module *modules;
124
125static struct module *find_module(const char *modname)
126{
127 struct module *mod;
128
129 for (mod = modules; mod; mod = mod->next)
130 if (strcmp(mod->name, modname) == 0)
131 break;
132 return mod;
133}
134
135static struct module *new_module(const char *modname)
136{
137 struct module *mod;
138 char *p;
139
140 mod = NOFAIL(malloc(sizeof(*mod)));
141 memset(mod, 0, sizeof(*mod));
142 p = NOFAIL(strdup(modname));
143
144 /* strip trailing .o */
145 if (strends(p, ".o")) {
146 p[strlen(p) - 2] = '\0';
147 mod->is_dot_o = 1;
148 }
149
150 /* add to list */
151 mod->name = p;
152 mod->gpl_compatible = -1;
153 mod->next = modules;
154 modules = mod;
155
156 return mod;
157}
158
159/* A hash of all exported symbols,
160 * struct symbol is also used for lists of unresolved symbols */
161
162#define SYMBOL_HASH_SIZE 1024
163
164struct symbol {
165 struct symbol *next;
166 struct module *module;
167 unsigned int crc;
168 int crc_valid;
169 char *namespace;
170 unsigned int weak:1;
171 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
172 unsigned int kernel:1; /* 1 if symbol is from kernel
173 * (only for external modules) **/
174 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
175 unsigned int is_static:1; /* 1 if symbol is not global */
176 enum export export; /* Type of export */
177 char name[0];
178};
179
180static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
181
182/* This is based on the hash agorithm from gdbm, via tdb */
183static inline unsigned int tdb_hash(const char *name)
184{
185 unsigned value; /* Used to compute the hash value. */
186 unsigned i; /* Used to cycle through random values. */
187
188 /* Set the initial value from the key size. */
189 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
190 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
191
192 return (1103515243 * value + 12345);
193}
194
195/**
196 * Allocate a new symbols for use in the hash of exported symbols or
197 * the list of unresolved symbols per module
198 **/
199static struct symbol *alloc_symbol(const char *name, unsigned int weak,
200 struct symbol *next)
201{
202 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
203
204 memset(s, 0, sizeof(*s));
205 strcpy(s->name, name);
206 s->weak = weak;
207 s->next = next;
208 s->is_static = 1;
209 return s;
210}
211
212/* For the hash of exported symbols */
213static struct symbol *new_symbol(const char *name, struct module *module,
214 enum export export)
215{
216 unsigned int hash;
217 struct symbol *new;
218
219 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
220 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
221 new->module = module;
222 new->export = export;
223 return new;
224}
225
226static struct symbol *find_symbol(const char *name)
227{
228 struct symbol *s;
229
230 /* For our purposes, .foo matches foo. PPC64 needs this. */
231 if (name[0] == '.')
232 name++;
233
234 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
235 if (strcmp(s->name, name) == 0)
236 return s;
237 }
238 return NULL;
239}
240
241static bool contains_namespace(struct namespace_list *list,
242 const char *namespace)
243{
244 struct namespace_list *ns_entry;
245
246 for (ns_entry = list; ns_entry != NULL; ns_entry = ns_entry->next)
247 if (strcmp(ns_entry->namespace, namespace) == 0)
248 return true;
249
250 return false;
251}
252
253static void add_namespace(struct namespace_list **list, const char *namespace)
254{
255 struct namespace_list *ns_entry;
256
257 if (!contains_namespace(*list, namespace)) {
258 ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
259 strlen(namespace) + 1));
260 strcpy(ns_entry->namespace, namespace);
261 ns_entry->next = *list;
262 *list = ns_entry;
263 }
264}
265
266static bool module_imports_namespace(struct module *module,
267 const char *namespace)
268{
269 return contains_namespace(module->imported_namespaces, namespace);
270}
271
272static const struct {
273 const char *str;
274 enum export export;
275} export_list[] = {
276 { .str = "EXPORT_SYMBOL", .export = export_plain },
277 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
278 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
279 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
280 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
281 { .str = "(unknown)", .export = export_unknown },
282};
283
284
285static const char *export_str(enum export ex)
286{
287 return export_list[ex].str;
288}
289
290static enum export export_no(const char *s)
291{
292 int i;
293
294 if (!s)
295 return export_unknown;
296 for (i = 0; export_list[i].export != export_unknown; i++) {
297 if (strcmp(export_list[i].str, s) == 0)
298 return export_list[i].export;
299 }
300 return export_unknown;
301}
302
303static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
304{
305 return (void *)elf->hdr +
306 elf->sechdrs[elf->secindex_strings].sh_offset +
307 sechdr->sh_name;
308}
309
310static const char *sec_name(struct elf_info *elf, int secindex)
311{
312 return sech_name(elf, &elf->sechdrs[secindex]);
313}
314
315#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
316
317static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
318{
319 const char *secname = sec_name(elf, sec);
320
321 if (strstarts(secname, "___ksymtab+"))
322 return export_plain;
323 else if (strstarts(secname, "___ksymtab_unused+"))
324 return export_unused;
325 else if (strstarts(secname, "___ksymtab_gpl+"))
326 return export_gpl;
327 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
328 return export_unused_gpl;
329 else if (strstarts(secname, "___ksymtab_gpl_future+"))
330 return export_gpl_future;
331 else
332 return export_unknown;
333}
334
335static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
336{
337 if (sec == elf->export_sec)
338 return export_plain;
339 else if (sec == elf->export_unused_sec)
340 return export_unused;
341 else if (sec == elf->export_gpl_sec)
342 return export_gpl;
343 else if (sec == elf->export_unused_gpl_sec)
344 return export_unused_gpl;
345 else if (sec == elf->export_gpl_future_sec)
346 return export_gpl_future;
347 else
348 return export_unknown;
349}
350
351static const char *namespace_from_kstrtabns(struct elf_info *info,
352 Elf_Sym *kstrtabns)
353{
354 char *value = info->ksymtab_strings + kstrtabns->st_value;
355 return value[0] ? value : NULL;
356}
357
358static void sym_update_namespace(const char *symname, const char *namespace)
359{
360 struct symbol *s = find_symbol(symname);
361
362 /*
363 * That symbol should have been created earlier and thus this is
364 * actually an assertion.
365 */
366 if (!s) {
367 merror("Could not update namespace(%s) for symbol %s\n",
368 namespace, symname);
369 return;
370 }
371
372 free(s->namespace);
373 s->namespace =
374 namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
375}
376
377/**
378 * Add an exported symbol - it may have already been added without a
379 * CRC, in this case just update the CRC
380 **/
381static struct symbol *sym_add_exported(const char *name, struct module *mod,
382 enum export export)
383{
384 struct symbol *s = find_symbol(name);
385
386 if (!s) {
387 s = new_symbol(name, mod, export);
388 } else {
389 if (!s->preloaded) {
390 warn("%s: '%s' exported twice. Previous export was in %s%s\n",
391 mod->name, name, s->module->name,
392 is_vmlinux(s->module->name) ? "" : ".ko");
393 } else {
394 /* In case Module.symvers was out of date */
395 s->module = mod;
396 }
397 }
398 s->preloaded = 0;
399 s->vmlinux = is_vmlinux(mod->name);
400 s->kernel = 0;
401 s->export = export;
402 return s;
403}
404
405static void sym_update_crc(const char *name, struct module *mod,
406 unsigned int crc, enum export export)
407{
408 struct symbol *s = find_symbol(name);
409
410 if (!s) {
411 s = new_symbol(name, mod, export);
412 /* Don't complain when we find it later. */
413 s->preloaded = 1;
414 }
415 s->crc = crc;
416 s->crc_valid = 1;
417}
418
419void *grab_file(const char *filename, unsigned long *size)
420{
421 struct stat st;
422 void *map = MAP_FAILED;
423 int fd;
424
425 fd = open(filename, O_RDONLY);
426 if (fd < 0)
427 return NULL;
428 if (fstat(fd, &st))
429 goto failed;
430
431 *size = st.st_size;
432 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
433
434failed:
435 close(fd);
436 if (map == MAP_FAILED)
437 return NULL;
438 return map;
439}
440
441/**
442 * Return a copy of the next line in a mmap'ed file.
443 * spaces in the beginning of the line is trimmed away.
444 * Return a pointer to a static buffer.
445 **/
446char *get_next_line(unsigned long *pos, void *file, unsigned long size)
447{
448 static char line[4096];
449 int skip = 1;
450 size_t len = 0;
451 signed char *p = (signed char *)file + *pos;
452 char *s = line;
453
454 for (; *pos < size ; (*pos)++) {
455 if (skip && isspace(*p)) {
456 p++;
457 continue;
458 }
459 skip = 0;
460 if (*p != '\n' && (*pos < size)) {
461 len++;
462 *s++ = *p++;
463 if (len > 4095)
464 break; /* Too long, stop */
465 } else {
466 /* End of string */
467 *s = '\0';
468 return line;
469 }
470 }
471 /* End of buffer */
472 return NULL;
473}
474
475void release_file(void *file, unsigned long size)
476{
477 munmap(file, size);
478}
479
480static int parse_elf(struct elf_info *info, const char *filename)
481{
482 unsigned int i;
483 Elf_Ehdr *hdr;
484 Elf_Shdr *sechdrs;
485 Elf_Sym *sym;
486 const char *secstrings;
487 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
488
489 hdr = grab_file(filename, &info->size);
490 if (!hdr) {
491 if (ignore_missing_files) {
492 fprintf(stderr, "%s: %s (ignored)\n", filename,
493 strerror(errno));
494 return 0;
495 }
496 perror(filename);
497 exit(1);
498 }
499 info->hdr = hdr;
500 if (info->size < sizeof(*hdr)) {
501 /* file too small, assume this is an empty .o file */
502 return 0;
503 }
504 /* Is this a valid ELF file? */
505 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
506 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
507 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
508 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
509 /* Not an ELF file - silently ignore it */
510 return 0;
511 }
512 /* Fix endianness in ELF header */
513 hdr->e_type = TO_NATIVE(hdr->e_type);
514 hdr->e_machine = TO_NATIVE(hdr->e_machine);
515 hdr->e_version = TO_NATIVE(hdr->e_version);
516 hdr->e_entry = TO_NATIVE(hdr->e_entry);
517 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
518 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
519 hdr->e_flags = TO_NATIVE(hdr->e_flags);
520 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
521 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
522 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
523 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
524 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
525 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
526 sechdrs = (void *)hdr + hdr->e_shoff;
527 info->sechdrs = sechdrs;
528
529 /* Check if file offset is correct */
530 if (hdr->e_shoff > info->size) {
531 fatal("section header offset=%lu in file '%s' is bigger than "
532 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
533 filename, info->size);
534 return 0;
535 }
536
537 if (hdr->e_shnum == SHN_UNDEF) {
538 /*
539 * There are more than 64k sections,
540 * read count from .sh_size.
541 */
542 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
543 }
544 else {
545 info->num_sections = hdr->e_shnum;
546 }
547 if (hdr->e_shstrndx == SHN_XINDEX) {
548 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
549 }
550 else {
551 info->secindex_strings = hdr->e_shstrndx;
552 }
553
554 /* Fix endianness in section headers */
555 for (i = 0; i < info->num_sections; i++) {
556 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
557 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
558 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
559 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
560 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
561 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
562 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
563 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
564 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
565 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
566 }
567 /* Find symbol table. */
568 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
569 for (i = 1; i < info->num_sections; i++) {
570 const char *secname;
571 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
572
573 if (!nobits && sechdrs[i].sh_offset > info->size) {
574 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
575 "sizeof(*hrd)=%zu\n", filename,
576 (unsigned long)sechdrs[i].sh_offset,
577 sizeof(*hdr));
578 return 0;
579 }
580 secname = secstrings + sechdrs[i].sh_name;
581 if (strcmp(secname, ".modinfo") == 0) {
582 if (nobits)
583 fatal("%s has NOBITS .modinfo\n", filename);
584 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
585 info->modinfo_len = sechdrs[i].sh_size;
586 } else if (strcmp(secname, "__ksymtab") == 0)
587 info->export_sec = i;
588 else if (strcmp(secname, "__ksymtab_unused") == 0)
589 info->export_unused_sec = i;
590 else if (strcmp(secname, "__ksymtab_gpl") == 0)
591 info->export_gpl_sec = i;
592 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
593 info->export_unused_gpl_sec = i;
594 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
595 info->export_gpl_future_sec = i;
596 else if (strcmp(secname, "__ksymtab_strings") == 0)
597 info->ksymtab_strings = (void *)hdr +
598 sechdrs[i].sh_offset -
599 sechdrs[i].sh_addr;
600
601 if (sechdrs[i].sh_type == SHT_SYMTAB) {
602 unsigned int sh_link_idx;
603 symtab_idx = i;
604 info->symtab_start = (void *)hdr +
605 sechdrs[i].sh_offset;
606 info->symtab_stop = (void *)hdr +
607 sechdrs[i].sh_offset + sechdrs[i].sh_size;
608 sh_link_idx = sechdrs[i].sh_link;
609 info->strtab = (void *)hdr +
610 sechdrs[sh_link_idx].sh_offset;
611 }
612
613 /* 32bit section no. table? ("more than 64k sections") */
614 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
615 symtab_shndx_idx = i;
616 info->symtab_shndx_start = (void *)hdr +
617 sechdrs[i].sh_offset;
618 info->symtab_shndx_stop = (void *)hdr +
619 sechdrs[i].sh_offset + sechdrs[i].sh_size;
620 }
621 }
622 if (!info->symtab_start)
623 fatal("%s has no symtab?\n", filename);
624
625 /* Fix endianness in symbols */
626 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
627 sym->st_shndx = TO_NATIVE(sym->st_shndx);
628 sym->st_name = TO_NATIVE(sym->st_name);
629 sym->st_value = TO_NATIVE(sym->st_value);
630 sym->st_size = TO_NATIVE(sym->st_size);
631 }
632
633 if (symtab_shndx_idx != ~0U) {
634 Elf32_Word *p;
635 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
636 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
637 filename, sechdrs[symtab_shndx_idx].sh_link,
638 symtab_idx);
639 /* Fix endianness */
640 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
641 p++)
642 *p = TO_NATIVE(*p);
643 }
644
645 return 1;
646}
647
648static void parse_elf_finish(struct elf_info *info)
649{
650 release_file(info->hdr, info->size);
651}
652
653static int ignore_undef_symbol(struct elf_info *info, const char *symname)
654{
655 /* ignore __this_module, it will be resolved shortly */
656 if (strcmp(symname, "__this_module") == 0)
657 return 1;
658 /* ignore global offset table */
659 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
660 return 1;
661 if (info->hdr->e_machine == EM_PPC)
662 /* Special register function linked on all modules during final link of .ko */
663 if (strstarts(symname, "_restgpr_") ||
664 strstarts(symname, "_savegpr_") ||
665 strstarts(symname, "_rest32gpr_") ||
666 strstarts(symname, "_save32gpr_") ||
667 strstarts(symname, "_restvr_") ||
668 strstarts(symname, "_savevr_"))
669 return 1;
670 if (info->hdr->e_machine == EM_PPC64)
671 /* Special register function linked on all modules during final link of .ko */
672 if (strstarts(symname, "_restgpr0_") ||
673 strstarts(symname, "_savegpr0_") ||
674 strstarts(symname, "_restvr_") ||
675 strstarts(symname, "_savevr_") ||
676 strcmp(symname, ".TOC.") == 0)
677 return 1;
678 /* Do not ignore this symbol */
679 return 0;
680}
681
682static void handle_modversions(struct module *mod, struct elf_info *info,
683 Elf_Sym *sym, const char *symname)
684{
685 unsigned int crc;
686 enum export export;
687 bool is_crc = false;
688 const char *name;
689
690 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
691 strstarts(symname, "__ksymtab"))
692 export = export_from_secname(info, get_secindex(info, sym));
693 else
694 export = export_from_sec(info, get_secindex(info, sym));
695
696 /* CRC'd symbol */
697 if (strstarts(symname, "__crc_")) {
698 is_crc = true;
699 crc = (unsigned int) sym->st_value;
700 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
701 unsigned int *crcp;
702
703 /* symbol points to the CRC in the ELF object */
704 crcp = (void *)info->hdr + sym->st_value +
705 info->sechdrs[sym->st_shndx].sh_offset -
706 (info->hdr->e_type != ET_REL ?
707 info->sechdrs[sym->st_shndx].sh_addr : 0);
708 crc = TO_NATIVE(*crcp);
709 }
710 sym_update_crc(symname + strlen("__crc_"), mod, crc,
711 export);
712 }
713
714 switch (sym->st_shndx) {
715 case SHN_COMMON:
716 if (strstarts(symname, "__gnu_lto_")) {
717 /* Should warn here, but modpost runs before the linker */
718 } else
719 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
720 break;
721 case SHN_UNDEF:
722 /* undefined symbol */
723 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
724 ELF_ST_BIND(sym->st_info) != STB_WEAK)
725 break;
726 if (ignore_undef_symbol(info, symname))
727 break;
728/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
729#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
730/* add compatibility with older glibc */
731#ifndef STT_SPARC_REGISTER
732#define STT_SPARC_REGISTER STT_REGISTER
733#endif
734 if (info->hdr->e_machine == EM_SPARC ||
735 info->hdr->e_machine == EM_SPARCV9) {
736 /* Ignore register directives. */
737 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
738 break;
739 if (symname[0] == '.') {
740 char *munged = NOFAIL(strdup(symname));
741 munged[0] = '_';
742 munged[1] = toupper(munged[1]);
743 symname = munged;
744 }
745 }
746#endif
747
748 if (is_crc) {
749 const char *e = is_vmlinux(mod->name) ?"":".ko";
750 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
751 symname + strlen("__crc_"), mod->name, e);
752 }
753 mod->unres = alloc_symbol(symname,
754 ELF_ST_BIND(sym->st_info) == STB_WEAK,
755 mod->unres);
756 break;
757 default:
758 /* All exported symbols */
759 if (strstarts(symname, "__ksymtab_")) {
760 name = symname + strlen("__ksymtab_");
761 sym_add_exported(name, mod, export);
762 }
763 if (strcmp(symname, "init_module") == 0)
764 mod->has_init = 1;
765 if (strcmp(symname, "cleanup_module") == 0)
766 mod->has_cleanup = 1;
767 break;
768 }
769}
770
771/**
772 * Parse tag=value strings from .modinfo section
773 **/
774static char *next_string(char *string, unsigned long *secsize)
775{
776 /* Skip non-zero chars */
777 while (string[0]) {
778 string++;
779 if ((*secsize)-- <= 1)
780 return NULL;
781 }
782
783 /* Skip any zero padding. */
784 while (!string[0]) {
785 string++;
786 if ((*secsize)-- <= 1)
787 return NULL;
788 }
789 return string;
790}
791
792static char *get_next_modinfo(struct elf_info *info, const char *tag,
793 char *prev)
794{
795 char *p;
796 unsigned int taglen = strlen(tag);
797 char *modinfo = info->modinfo;
798 unsigned long size = info->modinfo_len;
799
800 if (prev) {
801 size -= prev - modinfo;
802 modinfo = next_string(prev, &size);
803 }
804
805 for (p = modinfo; p; p = next_string(p, &size)) {
806 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
807 return p + taglen + 1;
808 }
809 return NULL;
810}
811
812static char *get_modinfo(struct elf_info *info, const char *tag)
813
814{
815 return get_next_modinfo(info, tag, NULL);
816}
817
818/**
819 * Test if string s ends in string sub
820 * return 0 if match
821 **/
822static int strrcmp(const char *s, const char *sub)
823{
824 int slen, sublen;
825
826 if (!s || !sub)
827 return 1;
828
829 slen = strlen(s);
830 sublen = strlen(sub);
831
832 if ((slen == 0) || (sublen == 0))
833 return 1;
834
835 if (sublen > slen)
836 return 1;
837
838 return memcmp(s + slen - sublen, sub, sublen);
839}
840
841static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
842{
843 if (sym)
844 return elf->strtab + sym->st_name;
845 else
846 return "(unknown)";
847}
848
849/* The pattern is an array of simple patterns.
850 * "foo" will match an exact string equal to "foo"
851 * "*foo" will match a string that ends with "foo"
852 * "foo*" will match a string that begins with "foo"
853 * "*foo*" will match a string that contains "foo"
854 */
855static int match(const char *sym, const char * const pat[])
856{
857 const char *p;
858 while (*pat) {
859 p = *pat++;
860 const char *endp = p + strlen(p) - 1;
861
862 /* "*foo*" */
863 if (*p == '*' && *endp == '*') {
864 char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
865 char *here = strstr(sym, bare);
866
867 free(bare);
868 if (here != NULL)
869 return 1;
870 }
871 /* "*foo" */
872 else if (*p == '*') {
873 if (strrcmp(sym, p + 1) == 0)
874 return 1;
875 }
876 /* "foo*" */
877 else if (*endp == '*') {
878 if (strncmp(sym, p, strlen(p) - 1) == 0)
879 return 1;
880 }
881 /* no wildcards */
882 else {
883 if (strcmp(p, sym) == 0)
884 return 1;
885 }
886 }
887 /* no match */
888 return 0;
889}
890
891/* sections that we do not want to do full section mismatch check on */
892static const char *const section_white_list[] =
893{
894 ".comment*",
895 ".debug*",
896 ".cranges", /* sh64 */
897 ".zdebug*", /* Compressed debug sections. */
898 ".GCC.command.line", /* record-gcc-switches */
899 ".mdebug*", /* alpha, score, mips etc. */
900 ".pdr", /* alpha, score, mips etc. */
901 ".stab*",
902 ".note*",
903 ".got*",
904 ".toc*",
905 ".xt.prop", /* xtensa */
906 ".xt.lit", /* xtensa */
907 ".arcextmap*", /* arc */
908 ".gnu.linkonce.arcext*", /* arc : modules */
909 ".cmem*", /* EZchip */
910 ".fmt_slot*", /* EZchip */
911 ".gnu.lto*",
912 ".discard.*",
913 NULL
914};
915
916/*
917 * This is used to find sections missing the SHF_ALLOC flag.
918 * The cause of this is often a section specified in assembler
919 * without "ax" / "aw".
920 */
921static void check_section(const char *modname, struct elf_info *elf,
922 Elf_Shdr *sechdr)
923{
924 const char *sec = sech_name(elf, sechdr);
925
926 if (sechdr->sh_type == SHT_PROGBITS &&
927 !(sechdr->sh_flags & SHF_ALLOC) &&
928 !match(sec, section_white_list)) {
929 warn("%s (%s): unexpected non-allocatable section.\n"
930 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
931 "Note that for example <linux/init.h> contains\n"
932 "section definitions for use in .S files.\n\n",
933 modname, sec);
934 }
935}
936
937
938
939#define ALL_INIT_DATA_SECTIONS \
940 ".init.setup", ".init.rodata", ".meminit.rodata", \
941 ".init.data", ".meminit.data"
942#define ALL_EXIT_DATA_SECTIONS \
943 ".exit.data", ".memexit.data"
944
945#define ALL_INIT_TEXT_SECTIONS \
946 ".init.text", ".meminit.text"
947#define ALL_EXIT_TEXT_SECTIONS \
948 ".exit.text", ".memexit.text"
949
950#define ALL_PCI_INIT_SECTIONS \
951 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
952 ".pci_fixup_enable", ".pci_fixup_resume", \
953 ".pci_fixup_resume_early", ".pci_fixup_suspend"
954
955#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
956#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
957
958#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
959#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
960
961#define DATA_SECTIONS ".data", ".data.rel"
962#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
963 ".kprobes.text", ".cpuidle.text"
964#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
965 ".fixup", ".entry.text", ".exception.text", ".text.*", \
966 ".coldtext"
967
968#define INIT_SECTIONS ".init.*"
969#define MEM_INIT_SECTIONS ".meminit.*"
970
971#define EXIT_SECTIONS ".exit.*"
972#define MEM_EXIT_SECTIONS ".memexit.*"
973
974#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
975 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
976
977/* init data sections */
978static const char *const init_data_sections[] =
979 { ALL_INIT_DATA_SECTIONS, NULL };
980
981/* all init sections */
982static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
983
984/* All init and exit sections (code + data) */
985static const char *const init_exit_sections[] =
986 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
987
988/* all text sections */
989static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
990
991/* data section */
992static const char *const data_sections[] = { DATA_SECTIONS, NULL };
993
994
995/* symbols in .data that may refer to init/exit sections */
996#define DEFAULT_SYMBOL_WHITE_LIST \
997 "*driver", \
998 "*_template", /* scsi uses *_template a lot */ \
999 "*_timer", /* arm uses ops structures named _timer a lot */ \
1000 "*_sht", /* scsi also used *_sht to some extent */ \
1001 "*_ops", \
1002 "*_probe", \
1003 "*_probe_one", \
1004 "*_console"
1005
1006static const char *const head_sections[] = { ".head.text*", NULL };
1007static const char *const linker_symbols[] =
1008 { "__init_begin", "_sinittext", "_einittext", NULL };
1009static const char *const optim_symbols[] = { "*.constprop.*", NULL };
1010
1011enum mismatch {
1012 TEXT_TO_ANY_INIT,
1013 DATA_TO_ANY_INIT,
1014 TEXT_TO_ANY_EXIT,
1015 DATA_TO_ANY_EXIT,
1016 XXXINIT_TO_SOME_INIT,
1017 XXXEXIT_TO_SOME_EXIT,
1018 ANY_INIT_TO_ANY_EXIT,
1019 ANY_EXIT_TO_ANY_INIT,
1020 EXPORT_TO_INIT_EXIT,
1021 EXTABLE_TO_NON_TEXT,
1022};
1023
1024/**
1025 * Describe how to match sections on different criterias:
1026 *
1027 * @fromsec: Array of sections to be matched.
1028 *
1029 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
1030 * this array is forbidden (black-list). Can be empty.
1031 *
1032 * @good_tosec: Relocations applied to a section in @fromsec must be
1033 * targetting sections in this array (white-list). Can be empty.
1034 *
1035 * @mismatch: Type of mismatch.
1036 *
1037 * @symbol_white_list: Do not match a relocation to a symbol in this list
1038 * even if it is targetting a section in @bad_to_sec.
1039 *
1040 * @handler: Specific handler to call when a match is found. If NULL,
1041 * default_mismatch_handler() will be called.
1042 *
1043 */
1044struct sectioncheck {
1045 const char *fromsec[20];
1046 const char *bad_tosec[20];
1047 const char *good_tosec[20];
1048 enum mismatch mismatch;
1049 const char *symbol_white_list[20];
1050 void (*handler)(const char *modname, struct elf_info *elf,
1051 const struct sectioncheck* const mismatch,
1052 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1053
1054};
1055
1056static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1057 const struct sectioncheck* const mismatch,
1058 Elf_Rela *r, Elf_Sym *sym,
1059 const char *fromsec);
1060
1061static const struct sectioncheck sectioncheck[] = {
1062/* Do not reference init/exit code/data from
1063 * normal code and data
1064 */
1065{
1066 .fromsec = { TEXT_SECTIONS, NULL },
1067 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1068 .mismatch = TEXT_TO_ANY_INIT,
1069 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1070},
1071{
1072 .fromsec = { DATA_SECTIONS, NULL },
1073 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1074 .mismatch = DATA_TO_ANY_INIT,
1075 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1076},
1077{
1078 .fromsec = { DATA_SECTIONS, NULL },
1079 .bad_tosec = { INIT_SECTIONS, NULL },
1080 .mismatch = DATA_TO_ANY_INIT,
1081 .symbol_white_list = {
1082 "*_template", "*_timer", "*_sht", "*_ops",
1083 "*_probe", "*_probe_one", "*_console", NULL
1084 },
1085},
1086{
1087 .fromsec = { TEXT_SECTIONS, NULL },
1088 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1089 .mismatch = TEXT_TO_ANY_EXIT,
1090 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1091},
1092{
1093 .fromsec = { DATA_SECTIONS, NULL },
1094 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1095 .mismatch = DATA_TO_ANY_EXIT,
1096 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1097},
1098/* Do not reference init code/data from meminit code/data */
1099{
1100 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1101 .bad_tosec = { INIT_SECTIONS, NULL },
1102 .mismatch = XXXINIT_TO_SOME_INIT,
1103 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1104},
1105/* Do not reference exit code/data from memexit code/data */
1106{
1107 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1108 .bad_tosec = { EXIT_SECTIONS, NULL },
1109 .mismatch = XXXEXIT_TO_SOME_EXIT,
1110 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1111},
1112/* Do not use exit code/data from init code */
1113{
1114 .fromsec = { ALL_INIT_SECTIONS, NULL },
1115 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1116 .mismatch = ANY_INIT_TO_ANY_EXIT,
1117 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1118},
1119/* Do not use init code/data from exit code */
1120{
1121 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1122 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1123 .mismatch = ANY_EXIT_TO_ANY_INIT,
1124 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1125},
1126{
1127 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1128 .bad_tosec = { INIT_SECTIONS, NULL },
1129 .mismatch = ANY_INIT_TO_ANY_EXIT,
1130 .symbol_white_list = { NULL },
1131},
1132/* Do not export init/exit functions or data */
1133{
1134 .fromsec = { "__ksymtab*", NULL },
1135 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1136 .mismatch = EXPORT_TO_INIT_EXIT,
1137 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1138},
1139{
1140 .fromsec = { "__ex_table", NULL },
1141 /* If you're adding any new black-listed sections in here, consider
1142 * adding a special 'printer' for them in scripts/check_extable.
1143 */
1144 .bad_tosec = { ".altinstr_replacement", NULL },
1145 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1146 .mismatch = EXTABLE_TO_NON_TEXT,
1147 .handler = extable_mismatch_handler,
1148}
1149};
1150
1151static const struct sectioncheck *section_mismatch(
1152 const char *fromsec, const char *tosec)
1153{
1154 int i;
1155 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1156 const struct sectioncheck *check = §ioncheck[0];
1157
1158 /*
1159 * The target section could be the SHT_NUL section when we're
1160 * handling relocations to un-resolved symbols, trying to match it
1161 * doesn't make much sense and causes build failures on parisc
1162 * architectures.
1163 */
1164 if (*tosec == '\0')
1165 return NULL;
1166
1167 for (i = 0; i < elems; i++) {
1168 if (match(fromsec, check->fromsec)) {
1169 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1170 return check;
1171 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1172 return check;
1173 }
1174 check++;
1175 }
1176 return NULL;
1177}
1178
1179/**
1180 * Whitelist to allow certain references to pass with no warning.
1181 *
1182 * Pattern 1:
1183 * If a module parameter is declared __initdata and permissions=0
1184 * then this is legal despite the warning generated.
1185 * We cannot see value of permissions here, so just ignore
1186 * this pattern.
1187 * The pattern is identified by:
1188 * tosec = .init.data
1189 * fromsec = .data*
1190 * atsym =__param*
1191 *
1192 * Pattern 1a:
1193 * module_param_call() ops can refer to __init set function if permissions=0
1194 * The pattern is identified by:
1195 * tosec = .init.text
1196 * fromsec = .data*
1197 * atsym = __param_ops_*
1198 *
1199 * Pattern 2:
1200 * Many drivers utilise a *driver container with references to
1201 * add, remove, probe functions etc.
1202 * the pattern is identified by:
1203 * tosec = init or exit section
1204 * fromsec = data section
1205 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1206 * *probe_one, *_console, *_timer
1207 *
1208 * Pattern 3:
1209 * Whitelist all references from .head.text to any init section
1210 *
1211 * Pattern 4:
1212 * Some symbols belong to init section but still it is ok to reference
1213 * these from non-init sections as these symbols don't have any memory
1214 * allocated for them and symbol address and value are same. So even
1215 * if init section is freed, its ok to reference those symbols.
1216 * For ex. symbols marking the init section boundaries.
1217 * This pattern is identified by
1218 * refsymname = __init_begin, _sinittext, _einittext
1219 *
1220 * Pattern 5:
1221 * GCC may optimize static inlines when fed constant arg(s) resulting
1222 * in functions like cpumask_empty() -- generating an associated symbol
1223 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1224 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1225 * meaningless section warning. May need to add isra symbols too...
1226 * This pattern is identified by
1227 * tosec = init section
1228 * fromsec = text section
1229 * refsymname = *.constprop.*
1230 *
1231 * Pattern 6:
1232 * Hide section mismatch warnings for ELF local symbols. The goal
1233 * is to eliminate false positive modpost warnings caused by
1234 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1235 * Autogenerated symbol names bypass modpost's "Pattern 2"
1236 * whitelisting, which relies on pattern-matching against symbol
1237 * names to work. (One situation where gcc can autogenerate ELF
1238 * local symbols is when "-fsection-anchors" is used.)
1239 **/
1240static int secref_whitelist(const struct sectioncheck *mismatch,
1241 const char *fromsec, const char *fromsym,
1242 const char *tosec, const char *tosym)
1243{
1244 /* Check for pattern 1 */
1245 if (match(tosec, init_data_sections) &&
1246 match(fromsec, data_sections) &&
1247 strstarts(fromsym, "__param"))
1248 return 0;
1249
1250 /* Check for pattern 1a */
1251 if (strcmp(tosec, ".init.text") == 0 &&
1252 match(fromsec, data_sections) &&
1253 strstarts(fromsym, "__param_ops_"))
1254 return 0;
1255
1256 /* Check for pattern 2 */
1257 if (match(tosec, init_exit_sections) &&
1258 match(fromsec, data_sections) &&
1259 match(fromsym, mismatch->symbol_white_list))
1260 return 0;
1261
1262 /* Check for pattern 3 */
1263 if (match(fromsec, head_sections) &&
1264 match(tosec, init_sections))
1265 return 0;
1266
1267 /* Check for pattern 4 */
1268 if (match(tosym, linker_symbols))
1269 return 0;
1270
1271 /* Check for pattern 5 */
1272 if (match(fromsec, text_sections) &&
1273 match(tosec, init_sections) &&
1274 match(fromsym, optim_symbols))
1275 return 0;
1276
1277 /* Check for pattern 6 */
1278 if (strstarts(fromsym, ".L"))
1279 return 0;
1280
1281 return 1;
1282}
1283
1284static inline int is_arm_mapping_symbol(const char *str)
1285{
1286 return str[0] == '$' && strchr("axtd", str[1])
1287 && (str[2] == '\0' || str[2] == '.');
1288}
1289
1290/*
1291 * If there's no name there, ignore it; likewise, ignore it if it's
1292 * one of the magic symbols emitted used by current ARM tools.
1293 *
1294 * Otherwise if find_symbols_between() returns those symbols, they'll
1295 * fail the whitelist tests and cause lots of false alarms ... fixable
1296 * only by merging __exit and __init sections into __text, bloating
1297 * the kernel (which is especially evil on embedded platforms).
1298 */
1299static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1300{
1301 const char *name = elf->strtab + sym->st_name;
1302
1303 if (!name || !strlen(name))
1304 return 0;
1305 return !is_arm_mapping_symbol(name);
1306}
1307
1308/**
1309 * Find symbol based on relocation record info.
1310 * In some cases the symbol supplied is a valid symbol so
1311 * return refsym. If st_name != 0 we assume this is a valid symbol.
1312 * In other cases the symbol needs to be looked up in the symbol table
1313 * based on section and address.
1314 * **/
1315static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1316 Elf_Sym *relsym)
1317{
1318 Elf_Sym *sym;
1319 Elf_Sym *near = NULL;
1320 Elf64_Sword distance = 20;
1321 Elf64_Sword d;
1322 unsigned int relsym_secindex;
1323
1324 if (relsym->st_name != 0)
1325 return relsym;
1326
1327 relsym_secindex = get_secindex(elf, relsym);
1328 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1329 if (get_secindex(elf, sym) != relsym_secindex)
1330 continue;
1331 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1332 continue;
1333 if (!is_valid_name(elf, sym))
1334 continue;
1335 if (sym->st_value == addr)
1336 return sym;
1337 /* Find a symbol nearby - addr are maybe negative */
1338 d = sym->st_value - addr;
1339 if (d < 0)
1340 d = addr - sym->st_value;
1341 if (d < distance) {
1342 distance = d;
1343 near = sym;
1344 }
1345 }
1346 /* We need a close match */
1347 if (distance < 20)
1348 return near;
1349 else
1350 return NULL;
1351}
1352
1353/*
1354 * Find symbols before or equal addr and after addr - in the section sec.
1355 * If we find two symbols with equal offset prefer one with a valid name.
1356 * The ELF format may have a better way to detect what type of symbol
1357 * it is, but this works for now.
1358 **/
1359static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1360 const char *sec)
1361{
1362 Elf_Sym *sym;
1363 Elf_Sym *near = NULL;
1364 Elf_Addr distance = ~0;
1365
1366 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1367 const char *symsec;
1368
1369 if (is_shndx_special(sym->st_shndx))
1370 continue;
1371 symsec = sec_name(elf, get_secindex(elf, sym));
1372 if (strcmp(symsec, sec) != 0)
1373 continue;
1374 if (!is_valid_name(elf, sym))
1375 continue;
1376 if (sym->st_value <= addr) {
1377 if ((addr - sym->st_value) < distance) {
1378 distance = addr - sym->st_value;
1379 near = sym;
1380 } else if ((addr - sym->st_value) == distance) {
1381 near = sym;
1382 }
1383 }
1384 }
1385 return near;
1386}
1387
1388/*
1389 * Convert a section name to the function/data attribute
1390 * .init.text => __init
1391 * .memexitconst => __memconst
1392 * etc.
1393 *
1394 * The memory of returned value has been allocated on a heap. The user of this
1395 * method should free it after usage.
1396*/
1397static char *sec2annotation(const char *s)
1398{
1399 if (match(s, init_exit_sections)) {
1400 char *p = NOFAIL(malloc(20));
1401 char *r = p;
1402
1403 *p++ = '_';
1404 *p++ = '_';
1405 if (*s == '.')
1406 s++;
1407 while (*s && *s != '.')
1408 *p++ = *s++;
1409 *p = '\0';
1410 if (*s == '.')
1411 s++;
1412 if (strstr(s, "rodata") != NULL)
1413 strcat(p, "const ");
1414 else if (strstr(s, "data") != NULL)
1415 strcat(p, "data ");
1416 else
1417 strcat(p, " ");
1418 return r;
1419 } else {
1420 return NOFAIL(strdup(""));
1421 }
1422}
1423
1424static int is_function(Elf_Sym *sym)
1425{
1426 if (sym)
1427 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1428 else
1429 return -1;
1430}
1431
1432static void print_section_list(const char * const list[20])
1433{
1434 const char *const *s = list;
1435
1436 while (*s) {
1437 fprintf(stderr, "%s", *s);
1438 s++;
1439 if (*s)
1440 fprintf(stderr, ", ");
1441 }
1442 fprintf(stderr, "\n");
1443}
1444
1445static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1446{
1447 switch (is_func) {
1448 case 0: *name = "variable"; *name_p = ""; break;
1449 case 1: *name = "function"; *name_p = "()"; break;
1450 default: *name = "(unknown reference)"; *name_p = ""; break;
1451 }
1452}
1453
1454/*
1455 * Print a warning about a section mismatch.
1456 * Try to find symbols near it so user can find it.
1457 * Check whitelist before warning - it may be a false positive.
1458 */
1459static void report_sec_mismatch(const char *modname,
1460 const struct sectioncheck *mismatch,
1461 const char *fromsec,
1462 unsigned long long fromaddr,
1463 const char *fromsym,
1464 int from_is_func,
1465 const char *tosec, const char *tosym,
1466 int to_is_func)
1467{
1468 const char *from, *from_p;
1469 const char *to, *to_p;
1470 char *prl_from;
1471 char *prl_to;
1472
1473 sec_mismatch_count++;
1474
1475 get_pretty_name(from_is_func, &from, &from_p);
1476 get_pretty_name(to_is_func, &to, &to_p);
1477
1478 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1479 "to the %s %s:%s%s\n",
1480 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1481 tosym, to_p);
1482
1483 switch (mismatch->mismatch) {
1484 case TEXT_TO_ANY_INIT:
1485 prl_from = sec2annotation(fromsec);
1486 prl_to = sec2annotation(tosec);
1487 fprintf(stderr,
1488 "The function %s%s() references\n"
1489 "the %s %s%s%s.\n"
1490 "This is often because %s lacks a %s\n"
1491 "annotation or the annotation of %s is wrong.\n",
1492 prl_from, fromsym,
1493 to, prl_to, tosym, to_p,
1494 fromsym, prl_to, tosym);
1495 free(prl_from);
1496 free(prl_to);
1497 break;
1498 case DATA_TO_ANY_INIT: {
1499 prl_to = sec2annotation(tosec);
1500 fprintf(stderr,
1501 "The variable %s references\n"
1502 "the %s %s%s%s\n"
1503 "If the reference is valid then annotate the\n"
1504 "variable with __init* or __refdata (see linux/init.h) "
1505 "or name the variable:\n",
1506 fromsym, to, prl_to, tosym, to_p);
1507 print_section_list(mismatch->symbol_white_list);
1508 free(prl_to);
1509 break;
1510 }
1511 case TEXT_TO_ANY_EXIT:
1512 prl_to = sec2annotation(tosec);
1513 fprintf(stderr,
1514 "The function %s() references a %s in an exit section.\n"
1515 "Often the %s %s%s has valid usage outside the exit section\n"
1516 "and the fix is to remove the %sannotation of %s.\n",
1517 fromsym, to, to, tosym, to_p, prl_to, tosym);
1518 free(prl_to);
1519 break;
1520 case DATA_TO_ANY_EXIT: {
1521 prl_to = sec2annotation(tosec);
1522 fprintf(stderr,
1523 "The variable %s references\n"
1524 "the %s %s%s%s\n"
1525 "If the reference is valid then annotate the\n"
1526 "variable with __exit* (see linux/init.h) or "
1527 "name the variable:\n",
1528 fromsym, to, prl_to, tosym, to_p);
1529 print_section_list(mismatch->symbol_white_list);
1530 free(prl_to);
1531 break;
1532 }
1533 case XXXINIT_TO_SOME_INIT:
1534 case XXXEXIT_TO_SOME_EXIT:
1535 prl_from = sec2annotation(fromsec);
1536 prl_to = sec2annotation(tosec);
1537 fprintf(stderr,
1538 "The %s %s%s%s references\n"
1539 "a %s %s%s%s.\n"
1540 "If %s is only used by %s then\n"
1541 "annotate %s with a matching annotation.\n",
1542 from, prl_from, fromsym, from_p,
1543 to, prl_to, tosym, to_p,
1544 tosym, fromsym, tosym);
1545 free(prl_from);
1546 free(prl_to);
1547 break;
1548 case ANY_INIT_TO_ANY_EXIT:
1549 prl_from = sec2annotation(fromsec);
1550 prl_to = sec2annotation(tosec);
1551 fprintf(stderr,
1552 "The %s %s%s%s references\n"
1553 "a %s %s%s%s.\n"
1554 "This is often seen when error handling "
1555 "in the init function\n"
1556 "uses functionality in the exit path.\n"
1557 "The fix is often to remove the %sannotation of\n"
1558 "%s%s so it may be used outside an exit section.\n",
1559 from, prl_from, fromsym, from_p,
1560 to, prl_to, tosym, to_p,
1561 prl_to, tosym, to_p);
1562 free(prl_from);
1563 free(prl_to);
1564 break;
1565 case ANY_EXIT_TO_ANY_INIT:
1566 prl_from = sec2annotation(fromsec);
1567 prl_to = sec2annotation(tosec);
1568 fprintf(stderr,
1569 "The %s %s%s%s references\n"
1570 "a %s %s%s%s.\n"
1571 "This is often seen when error handling "
1572 "in the exit function\n"
1573 "uses functionality in the init path.\n"
1574 "The fix is often to remove the %sannotation of\n"
1575 "%s%s so it may be used outside an init section.\n",
1576 from, prl_from, fromsym, from_p,
1577 to, prl_to, tosym, to_p,
1578 prl_to, tosym, to_p);
1579 free(prl_from);
1580 free(prl_to);
1581 break;
1582 case EXPORT_TO_INIT_EXIT:
1583 prl_to = sec2annotation(tosec);
1584 fprintf(stderr,
1585 "The symbol %s is exported and annotated %s\n"
1586 "Fix this by removing the %sannotation of %s "
1587 "or drop the export.\n",
1588 tosym, prl_to, prl_to, tosym);
1589 free(prl_to);
1590 break;
1591 case EXTABLE_TO_NON_TEXT:
1592 fatal("There's a special handler for this mismatch type, "
1593 "we should never get here.");
1594 break;
1595 }
1596 fprintf(stderr, "\n");
1597}
1598
1599static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1600 const struct sectioncheck* const mismatch,
1601 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1602{
1603 const char *tosec;
1604 Elf_Sym *to;
1605 Elf_Sym *from;
1606 const char *tosym;
1607 const char *fromsym;
1608
1609 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1610 fromsym = sym_name(elf, from);
1611
1612 if (strstarts(fromsym, "reference___initcall"))
1613 return;
1614
1615 tosec = sec_name(elf, get_secindex(elf, sym));
1616 to = find_elf_symbol(elf, r->r_addend, sym);
1617 tosym = sym_name(elf, to);
1618
1619 /* check whitelist - we may ignore it */
1620 if (secref_whitelist(mismatch,
1621 fromsec, fromsym, tosec, tosym)) {
1622 report_sec_mismatch(modname, mismatch,
1623 fromsec, r->r_offset, fromsym,
1624 is_function(from), tosec, tosym,
1625 is_function(to));
1626 }
1627}
1628
1629static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1630{
1631 if (section_index > elf->num_sections)
1632 fatal("section_index is outside elf->num_sections!\n");
1633
1634 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1635}
1636
1637/*
1638 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1639 * to know the sizeof(struct exception_table_entry) for the target architecture.
1640 */
1641static unsigned int extable_entry_size = 0;
1642static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1643{
1644 /*
1645 * If we're currently checking the second relocation within __ex_table,
1646 * that relocation offset tells us the offsetof(struct
1647 * exception_table_entry, fixup) which is equal to sizeof(struct
1648 * exception_table_entry) divided by two. We use that to our advantage
1649 * since there's no portable way to get that size as every architecture
1650 * seems to go with different sized types. Not pretty but better than
1651 * hard-coding the size for every architecture..
1652 */
1653 if (!extable_entry_size)
1654 extable_entry_size = r->r_offset * 2;
1655}
1656
1657static inline bool is_extable_fault_address(Elf_Rela *r)
1658{
1659 /*
1660 * extable_entry_size is only discovered after we've handled the
1661 * _second_ relocation in __ex_table, so only abort when we're not
1662 * handling the first reloc and extable_entry_size is zero.
1663 */
1664 if (r->r_offset && extable_entry_size == 0)
1665 fatal("extable_entry size hasn't been discovered!\n");
1666
1667 return ((r->r_offset == 0) ||
1668 (r->r_offset % extable_entry_size == 0));
1669}
1670
1671#define is_second_extable_reloc(Start, Cur, Sec) \
1672 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1673
1674static void report_extable_warnings(const char* modname, struct elf_info* elf,
1675 const struct sectioncheck* const mismatch,
1676 Elf_Rela* r, Elf_Sym* sym,
1677 const char* fromsec, const char* tosec)
1678{
1679 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1680 const char* fromsym_name = sym_name(elf, fromsym);
1681 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1682 const char* tosym_name = sym_name(elf, tosym);
1683 const char* from_pretty_name;
1684 const char* from_pretty_name_p;
1685 const char* to_pretty_name;
1686 const char* to_pretty_name_p;
1687
1688 get_pretty_name(is_function(fromsym),
1689 &from_pretty_name, &from_pretty_name_p);
1690 get_pretty_name(is_function(tosym),
1691 &to_pretty_name, &to_pretty_name_p);
1692
1693 warn("%s(%s+0x%lx): Section mismatch in reference"
1694 " from the %s %s%s to the %s %s:%s%s\n",
1695 modname, fromsec, (long)r->r_offset, from_pretty_name,
1696 fromsym_name, from_pretty_name_p,
1697 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1698
1699 if (!match(tosec, mismatch->bad_tosec) &&
1700 is_executable_section(elf, get_secindex(elf, sym)))
1701 fprintf(stderr,
1702 "The relocation at %s+0x%lx references\n"
1703 "section \"%s\" which is not in the list of\n"
1704 "authorized sections. If you're adding a new section\n"
1705 "and/or if this reference is valid, add \"%s\" to the\n"
1706 "list of authorized sections to jump to on fault.\n"
1707 "This can be achieved by adding \"%s\" to \n"
1708 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1709 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1710}
1711
1712static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1713 const struct sectioncheck* const mismatch,
1714 Elf_Rela* r, Elf_Sym* sym,
1715 const char *fromsec)
1716{
1717 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1718
1719 sec_mismatch_count++;
1720
1721 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
1722
1723 if (match(tosec, mismatch->bad_tosec))
1724 fatal("The relocation at %s+0x%lx references\n"
1725 "section \"%s\" which is black-listed.\n"
1726 "Something is seriously wrong and should be fixed.\n"
1727 "You might get more information about where this is\n"
1728 "coming from by using scripts/check_extable.sh %s\n",
1729 fromsec, (long)r->r_offset, tosec, modname);
1730 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1731 if (is_extable_fault_address(r))
1732 fatal("The relocation at %s+0x%lx references\n"
1733 "section \"%s\" which is not executable, IOW\n"
1734 "it is not possible for the kernel to fault\n"
1735 "at that address. Something is seriously wrong\n"
1736 "and should be fixed.\n",
1737 fromsec, (long)r->r_offset, tosec);
1738 else
1739 fatal("The relocation at %s+0x%lx references\n"
1740 "section \"%s\" which is not executable, IOW\n"
1741 "the kernel will fault if it ever tries to\n"
1742 "jump to it. Something is seriously wrong\n"
1743 "and should be fixed.\n",
1744 fromsec, (long)r->r_offset, tosec);
1745 }
1746}
1747
1748static void check_section_mismatch(const char *modname, struct elf_info *elf,
1749 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1750{
1751 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1752 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1753
1754 if (mismatch) {
1755 if (mismatch->handler)
1756 mismatch->handler(modname, elf, mismatch,
1757 r, sym, fromsec);
1758 else
1759 default_mismatch_handler(modname, elf, mismatch,
1760 r, sym, fromsec);
1761 }
1762}
1763
1764static unsigned int *reloc_location(struct elf_info *elf,
1765 Elf_Shdr *sechdr, Elf_Rela *r)
1766{
1767 Elf_Shdr *sechdrs = elf->sechdrs;
1768 int section = sechdr->sh_info;
1769
1770 return (void *)elf->hdr + sechdrs[section].sh_offset +
1771 r->r_offset;
1772}
1773
1774static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1775{
1776 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1777 unsigned int *location = reloc_location(elf, sechdr, r);
1778
1779 switch (r_typ) {
1780 case R_386_32:
1781 r->r_addend = TO_NATIVE(*location);
1782 break;
1783 case R_386_PC32:
1784 r->r_addend = TO_NATIVE(*location) + 4;
1785 /* For CONFIG_RELOCATABLE=y */
1786 if (elf->hdr->e_type == ET_EXEC)
1787 r->r_addend += r->r_offset;
1788 break;
1789 }
1790 return 0;
1791}
1792
1793#ifndef R_ARM_CALL
1794#define R_ARM_CALL 28
1795#endif
1796#ifndef R_ARM_JUMP24
1797#define R_ARM_JUMP24 29
1798#endif
1799
1800#ifndef R_ARM_THM_CALL
1801#define R_ARM_THM_CALL 10
1802#endif
1803#ifndef R_ARM_THM_JUMP24
1804#define R_ARM_THM_JUMP24 30
1805#endif
1806#ifndef R_ARM_THM_JUMP19
1807#define R_ARM_THM_JUMP19 51
1808#endif
1809
1810static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1811{
1812 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1813
1814 switch (r_typ) {
1815 case R_ARM_ABS32:
1816 /* From ARM ABI: (S + A) | T */
1817 r->r_addend = (int)(long)
1818 (elf->symtab_start + ELF_R_SYM(r->r_info));
1819 break;
1820 case R_ARM_PC24:
1821 case R_ARM_CALL:
1822 case R_ARM_JUMP24:
1823 case R_ARM_THM_CALL:
1824 case R_ARM_THM_JUMP24:
1825 case R_ARM_THM_JUMP19:
1826 /* From ARM ABI: ((S + A) | T) - P */
1827 r->r_addend = (int)(long)(elf->hdr +
1828 sechdr->sh_offset +
1829 (r->r_offset - sechdr->sh_addr));
1830 break;
1831 default:
1832 return 1;
1833 }
1834 return 0;
1835}
1836
1837static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1838{
1839 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1840 unsigned int *location = reloc_location(elf, sechdr, r);
1841 unsigned int inst;
1842
1843 if (r_typ == R_MIPS_HI16)
1844 return 1; /* skip this */
1845 inst = TO_NATIVE(*location);
1846 switch (r_typ) {
1847 case R_MIPS_LO16:
1848 r->r_addend = inst & 0xffff;
1849 break;
1850 case R_MIPS_26:
1851 r->r_addend = (inst & 0x03ffffff) << 2;
1852 break;
1853 case R_MIPS_32:
1854 r->r_addend = inst;
1855 break;
1856 }
1857 return 0;
1858}
1859
1860static void section_rela(const char *modname, struct elf_info *elf,
1861 Elf_Shdr *sechdr)
1862{
1863 Elf_Sym *sym;
1864 Elf_Rela *rela;
1865 Elf_Rela r;
1866 unsigned int r_sym;
1867 const char *fromsec;
1868
1869 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1870 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1871
1872 fromsec = sech_name(elf, sechdr);
1873 fromsec += strlen(".rela");
1874 /* if from section (name) is know good then skip it */
1875 if (match(fromsec, section_white_list))
1876 return;
1877
1878 for (rela = start; rela < stop; rela++) {
1879 r.r_offset = TO_NATIVE(rela->r_offset);
1880#if KERNEL_ELFCLASS == ELFCLASS64
1881 if (elf->hdr->e_machine == EM_MIPS) {
1882 unsigned int r_typ;
1883 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1884 r_sym = TO_NATIVE(r_sym);
1885 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1886 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1887 } else {
1888 r.r_info = TO_NATIVE(rela->r_info);
1889 r_sym = ELF_R_SYM(r.r_info);
1890 }
1891#else
1892 r.r_info = TO_NATIVE(rela->r_info);
1893 r_sym = ELF_R_SYM(r.r_info);
1894#endif
1895 r.r_addend = TO_NATIVE(rela->r_addend);
1896 sym = elf->symtab_start + r_sym;
1897 /* Skip special sections */
1898 if (is_shndx_special(sym->st_shndx))
1899 continue;
1900 if (is_second_extable_reloc(start, rela, fromsec))
1901 find_extable_entry_size(fromsec, &r);
1902 check_section_mismatch(modname, elf, &r, sym, fromsec);
1903 }
1904}
1905
1906static void section_rel(const char *modname, struct elf_info *elf,
1907 Elf_Shdr *sechdr)
1908{
1909 Elf_Sym *sym;
1910 Elf_Rel *rel;
1911 Elf_Rela r;
1912 unsigned int r_sym;
1913 const char *fromsec;
1914
1915 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1916 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1917
1918 fromsec = sech_name(elf, sechdr);
1919 fromsec += strlen(".rel");
1920 /* if from section (name) is know good then skip it */
1921 if (match(fromsec, section_white_list))
1922 return;
1923
1924 for (rel = start; rel < stop; rel++) {
1925 r.r_offset = TO_NATIVE(rel->r_offset);
1926#if KERNEL_ELFCLASS == ELFCLASS64
1927 if (elf->hdr->e_machine == EM_MIPS) {
1928 unsigned int r_typ;
1929 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1930 r_sym = TO_NATIVE(r_sym);
1931 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1932 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1933 } else {
1934 r.r_info = TO_NATIVE(rel->r_info);
1935 r_sym = ELF_R_SYM(r.r_info);
1936 }
1937#else
1938 r.r_info = TO_NATIVE(rel->r_info);
1939 r_sym = ELF_R_SYM(r.r_info);
1940#endif
1941 r.r_addend = 0;
1942 switch (elf->hdr->e_machine) {
1943 case EM_386:
1944 if (addend_386_rel(elf, sechdr, &r))
1945 continue;
1946 break;
1947 case EM_ARM:
1948 if (addend_arm_rel(elf, sechdr, &r))
1949 continue;
1950 break;
1951 case EM_MIPS:
1952 if (addend_mips_rel(elf, sechdr, &r))
1953 continue;
1954 break;
1955 }
1956 sym = elf->symtab_start + r_sym;
1957 /* Skip special sections */
1958 if (is_shndx_special(sym->st_shndx))
1959 continue;
1960 if (is_second_extable_reloc(start, rel, fromsec))
1961 find_extable_entry_size(fromsec, &r);
1962 check_section_mismatch(modname, elf, &r, sym, fromsec);
1963 }
1964}
1965
1966/**
1967 * A module includes a number of sections that are discarded
1968 * either when loaded or when used as built-in.
1969 * For loaded modules all functions marked __init and all data
1970 * marked __initdata will be discarded when the module has been initialized.
1971 * Likewise for modules used built-in the sections marked __exit
1972 * are discarded because __exit marked function are supposed to be called
1973 * only when a module is unloaded which never happens for built-in modules.
1974 * The check_sec_ref() function traverses all relocation records
1975 * to find all references to a section that reference a section that will
1976 * be discarded and warns about it.
1977 **/
1978static void check_sec_ref(struct module *mod, const char *modname,
1979 struct elf_info *elf)
1980{
1981 int i;
1982 Elf_Shdr *sechdrs = elf->sechdrs;
1983
1984 /* Walk through all sections */
1985 for (i = 0; i < elf->num_sections; i++) {
1986 check_section(modname, elf, &elf->sechdrs[i]);
1987 /* We want to process only relocation sections and not .init */
1988 if (sechdrs[i].sh_type == SHT_RELA)
1989 section_rela(modname, elf, &elf->sechdrs[i]);
1990 else if (sechdrs[i].sh_type == SHT_REL)
1991 section_rel(modname, elf, &elf->sechdrs[i]);
1992 }
1993}
1994
1995static char *remove_dot(char *s)
1996{
1997 size_t n = strcspn(s, ".");
1998
1999 if (n && s[n]) {
2000 size_t m = strspn(s + n + 1, "0123456789");
2001 if (m && (s[n + m] == '.' || s[n + m] == 0))
2002 s[n] = 0;
2003 }
2004 return s;
2005}
2006
2007static void read_symbols(const char *modname)
2008{
2009 const char *symname;
2010 char *version;
2011 char *license;
2012 char *namespace;
2013 struct module *mod;
2014 struct elf_info info = { };
2015 Elf_Sym *sym;
2016
2017 if (!parse_elf(&info, modname))
2018 return;
2019
2020 mod = new_module(modname);
2021
2022 /* When there's no vmlinux, don't print warnings about
2023 * unresolved symbols (since there'll be too many ;) */
2024 if (is_vmlinux(modname)) {
2025 have_vmlinux = 1;
2026 mod->skip = 1;
2027 }
2028
2029 license = get_modinfo(&info, "license");
2030 if (!license && !is_vmlinux(modname))
2031 warn("modpost: missing MODULE_LICENSE() in %s\n"
2032 "see include/linux/module.h for "
2033 "more information\n", modname);
2034 while (license) {
2035 if (license_is_gpl_compatible(license))
2036 mod->gpl_compatible = 1;
2037 else {
2038 mod->gpl_compatible = 0;
2039 break;
2040 }
2041 license = get_next_modinfo(&info, "license", license);
2042 }
2043
2044 namespace = get_modinfo(&info, "import_ns");
2045 while (namespace) {
2046 add_namespace(&mod->imported_namespaces, namespace);
2047 namespace = get_next_modinfo(&info, "import_ns", namespace);
2048 }
2049
2050 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2051 symname = remove_dot(info.strtab + sym->st_name);
2052
2053 handle_modversions(mod, &info, sym, symname);
2054 handle_moddevtable(mod, &info, sym, symname);
2055 }
2056
2057 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
2058 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2059 symname = remove_dot(info.strtab + sym->st_name);
2060
2061 if (strstarts(symname, "__kstrtabns_"))
2062 sym_update_namespace(symname + strlen("__kstrtabns_"),
2063 namespace_from_kstrtabns(&info,
2064 sym));
2065 }
2066
2067 // check for static EXPORT_SYMBOL_* functions && global vars
2068 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2069 unsigned char bind = ELF_ST_BIND(sym->st_info);
2070
2071 if (bind == STB_GLOBAL || bind == STB_WEAK) {
2072 struct symbol *s =
2073 find_symbol(remove_dot(info.strtab +
2074 sym->st_name));
2075
2076 if (s)
2077 s->is_static = 0;
2078 }
2079 }
2080
2081 if (!is_vmlinux(modname) || vmlinux_section_warnings)
2082 check_sec_ref(mod, modname, &info);
2083
2084 version = get_modinfo(&info, "version");
2085 if (version)
2086 maybe_frob_rcs_version(modname, version, info.modinfo,
2087 version - (char *)info.hdr);
2088 if (version || (all_versions && !is_vmlinux(modname)))
2089 get_src_version(modname, mod->srcversion,
2090 sizeof(mod->srcversion)-1);
2091
2092 parse_elf_finish(&info);
2093
2094 /* Our trick to get versioning for module struct etc. - it's
2095 * never passed as an argument to an exported function, so
2096 * the automatic versioning doesn't pick it up, but it's really
2097 * important anyhow */
2098 if (modversions)
2099 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2100}
2101
2102static void read_symbols_from_files(const char *filename)
2103{
2104 FILE *in = stdin;
2105 char fname[PATH_MAX];
2106
2107 if (strcmp(filename, "-") != 0) {
2108 in = fopen(filename, "r");
2109 if (!in)
2110 fatal("Can't open filenames file %s: %m", filename);
2111 }
2112
2113 while (fgets(fname, PATH_MAX, in) != NULL) {
2114 if (strends(fname, "\n"))
2115 fname[strlen(fname)-1] = '\0';
2116 read_symbols(fname);
2117 }
2118
2119 if (in != stdin)
2120 fclose(in);
2121}
2122
2123#define SZ 500
2124
2125/* We first write the generated file into memory using the
2126 * following helper, then compare to the file on disk and
2127 * only update the later if anything changed */
2128
2129void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2130 const char *fmt, ...)
2131{
2132 char tmp[SZ];
2133 int len;
2134 va_list ap;
2135
2136 va_start(ap, fmt);
2137 len = vsnprintf(tmp, SZ, fmt, ap);
2138 buf_write(buf, tmp, len);
2139 va_end(ap);
2140}
2141
2142void buf_write(struct buffer *buf, const char *s, int len)
2143{
2144 if (buf->size - buf->pos < len) {
2145 buf->size += len + SZ;
2146 buf->p = NOFAIL(realloc(buf->p, buf->size));
2147 }
2148 strncpy(buf->p + buf->pos, s, len);
2149 buf->pos += len;
2150}
2151
2152static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2153{
2154 const char *e = is_vmlinux(m) ?"":".ko";
2155
2156 switch (exp) {
2157 case export_gpl:
2158 fatal("modpost: GPL-incompatible module %s%s "
2159 "uses GPL-only symbol '%s'\n", m, e, s);
2160 break;
2161 case export_unused_gpl:
2162 fatal("modpost: GPL-incompatible module %s%s "
2163 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2164 break;
2165 case export_gpl_future:
2166 warn("modpost: GPL-incompatible module %s%s "
2167 "uses future GPL-only symbol '%s'\n", m, e, s);
2168 break;
2169 case export_plain:
2170 case export_unused:
2171 case export_unknown:
2172 /* ignore */
2173 break;
2174 }
2175}
2176
2177static void check_for_unused(enum export exp, const char *m, const char *s)
2178{
2179 const char *e = is_vmlinux(m) ?"":".ko";
2180
2181 switch (exp) {
2182 case export_unused:
2183 case export_unused_gpl:
2184 warn("modpost: module %s%s "
2185 "uses symbol '%s' marked UNUSED\n", m, e, s);
2186 break;
2187 default:
2188 /* ignore */
2189 break;
2190 }
2191}
2192
2193static int check_exports(struct module *mod)
2194{
2195 struct symbol *s, *exp;
2196 int err = 0;
2197
2198 for (s = mod->unres; s; s = s->next) {
2199 const char *basename;
2200 exp = find_symbol(s->name);
2201 if (!exp || exp->module == mod) {
2202 if (have_vmlinux && !s->weak) {
2203 if (warn_unresolved) {
2204 warn("\"%s\" [%s.ko] undefined!\n",
2205 s->name, mod->name);
2206 } else {
2207 merror("\"%s\" [%s.ko] undefined!\n",
2208 s->name, mod->name);
2209 err = 1;
2210 }
2211 }
2212 continue;
2213 }
2214 basename = strrchr(mod->name, '/');
2215 if (basename)
2216 basename++;
2217 else
2218 basename = mod->name;
2219
2220 if (exp->namespace) {
2221 add_namespace(&mod->required_namespaces,
2222 exp->namespace);
2223
2224 if (!write_namespace_deps &&
2225 !module_imports_namespace(mod, exp->namespace)) {
2226 warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
2227 basename, exp->name, exp->namespace);
2228 }
2229 }
2230
2231 if (!mod->gpl_compatible)
2232 check_for_gpl_usage(exp->export, basename, exp->name);
2233 check_for_unused(exp->export, basename, exp->name);
2234 }
2235
2236 return err;
2237}
2238
2239static int check_modname_len(struct module *mod)
2240{
2241 const char *mod_name;
2242
2243 mod_name = strrchr(mod->name, '/');
2244 if (mod_name == NULL)
2245 mod_name = mod->name;
2246 else
2247 mod_name++;
2248 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2249 merror("module name is too long [%s.ko]\n", mod->name);
2250 return 1;
2251 }
2252
2253 return 0;
2254}
2255
2256/**
2257 * Header for the generated file
2258 **/
2259static void add_header(struct buffer *b, struct module *mod)
2260{
2261 buf_printf(b, "#include <linux/build-salt.h>\n");
2262 buf_printf(b, "#include <linux/module.h>\n");
2263 buf_printf(b, "#include <linux/vermagic.h>\n");
2264 buf_printf(b, "#include <linux/compiler.h>\n");
2265 buf_printf(b, "\n");
2266 buf_printf(b, "BUILD_SALT;\n");
2267 buf_printf(b, "\n");
2268 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2269 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2270 buf_printf(b, "\n");
2271 buf_printf(b, "__visible struct module __this_module\n");
2272 buf_printf(b, "__section(.gnu.linkonce.this_module) = {\n");
2273 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2274 if (mod->has_init)
2275 buf_printf(b, "\t.init = init_module,\n");
2276 if (mod->has_cleanup)
2277 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2278 "\t.exit = cleanup_module,\n"
2279 "#endif\n");
2280 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2281 buf_printf(b, "};\n");
2282}
2283
2284static void add_intree_flag(struct buffer *b, int is_intree)
2285{
2286 if (is_intree)
2287 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2288}
2289
2290/* Cannot check for assembler */
2291static void add_retpoline(struct buffer *b)
2292{
2293 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2294 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2295 buf_printf(b, "#endif\n");
2296}
2297
2298static void add_staging_flag(struct buffer *b, const char *name)
2299{
2300 if (strstarts(name, "drivers/staging"))
2301 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2302}
2303
2304/**
2305 * Record CRCs for unresolved symbols
2306 **/
2307static int add_versions(struct buffer *b, struct module *mod)
2308{
2309 struct symbol *s, *exp;
2310 int err = 0;
2311
2312 for (s = mod->unres; s; s = s->next) {
2313 exp = find_symbol(s->name);
2314 if (!exp || exp->module == mod)
2315 continue;
2316 s->module = exp->module;
2317 s->crc_valid = exp->crc_valid;
2318 s->crc = exp->crc;
2319 }
2320
2321 if (!modversions)
2322 return err;
2323
2324 buf_printf(b, "\n");
2325 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2326 buf_printf(b, "__used __section(__versions) = {\n");
2327
2328 for (s = mod->unres; s; s = s->next) {
2329 if (!s->module)
2330 continue;
2331 if (!s->crc_valid) {
2332 warn("\"%s\" [%s.ko] has no CRC!\n",
2333 s->name, mod->name);
2334 continue;
2335 }
2336 if (strlen(s->name) >= MODULE_NAME_LEN) {
2337 merror("too long symbol \"%s\" [%s.ko]\n",
2338 s->name, mod->name);
2339 err = 1;
2340 break;
2341 }
2342 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2343 s->crc, s->name);
2344 }
2345
2346 buf_printf(b, "};\n");
2347
2348 return err;
2349}
2350
2351static void add_depends(struct buffer *b, struct module *mod)
2352{
2353 struct symbol *s;
2354 int first = 1;
2355
2356 /* Clear ->seen flag of modules that own symbols needed by this. */
2357 for (s = mod->unres; s; s = s->next)
2358 if (s->module)
2359 s->module->seen = is_vmlinux(s->module->name);
2360
2361 buf_printf(b, "\n");
2362 buf_printf(b, "MODULE_INFO(depends, \"");
2363 for (s = mod->unres; s; s = s->next) {
2364 const char *p;
2365 if (!s->module)
2366 continue;
2367
2368 if (s->module->seen)
2369 continue;
2370
2371 s->module->seen = 1;
2372 p = strrchr(s->module->name, '/');
2373 if (p)
2374 p++;
2375 else
2376 p = s->module->name;
2377 buf_printf(b, "%s%s", first ? "" : ",", p);
2378 first = 0;
2379 }
2380 buf_printf(b, "\");\n");
2381}
2382
2383static void add_srcversion(struct buffer *b, struct module *mod)
2384{
2385 if (mod->srcversion[0]) {
2386 buf_printf(b, "\n");
2387 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2388 mod->srcversion);
2389 }
2390}
2391
2392static void write_if_changed(struct buffer *b, const char *fname)
2393{
2394 char *tmp;
2395 FILE *file;
2396 struct stat st;
2397
2398 file = fopen(fname, "r");
2399 if (!file)
2400 goto write;
2401
2402 if (fstat(fileno(file), &st) < 0)
2403 goto close_write;
2404
2405 if (st.st_size != b->pos)
2406 goto close_write;
2407
2408 tmp = NOFAIL(malloc(b->pos));
2409 if (fread(tmp, 1, b->pos, file) != b->pos)
2410 goto free_write;
2411
2412 if (memcmp(tmp, b->p, b->pos) != 0)
2413 goto free_write;
2414
2415 free(tmp);
2416 fclose(file);
2417 return;
2418
2419 free_write:
2420 free(tmp);
2421 close_write:
2422 fclose(file);
2423 write:
2424 file = fopen(fname, "w");
2425 if (!file) {
2426 perror(fname);
2427 exit(1);
2428 }
2429 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2430 perror(fname);
2431 exit(1);
2432 }
2433 fclose(file);
2434}
2435
2436/* parse Module.symvers file. line format:
2437 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2438 **/
2439static void read_dump(const char *fname, unsigned int kernel)
2440{
2441 unsigned long size, pos = 0;
2442 void *file = grab_file(fname, &size);
2443 char *line;
2444
2445 if (!file)
2446 /* No symbol versions, silently ignore */
2447 return;
2448
2449 while ((line = get_next_line(&pos, file, size))) {
2450 char *symname, *namespace, *modname, *d, *export, *end;
2451 unsigned int crc;
2452 struct module *mod;
2453 struct symbol *s;
2454
2455 if (!(symname = strchr(line, '\t')))
2456 goto fail;
2457 *symname++ = '\0';
2458 if (!(namespace = strchr(symname, '\t')))
2459 goto fail;
2460 *namespace++ = '\0';
2461 if (!(modname = strchr(namespace, '\t')))
2462 goto fail;
2463 *modname++ = '\0';
2464 if ((export = strchr(modname, '\t')) != NULL)
2465 *export++ = '\0';
2466 if (export && ((end = strchr(export, '\t')) != NULL))
2467 *end = '\0';
2468 crc = strtoul(line, &d, 16);
2469 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2470 goto fail;
2471 mod = find_module(modname);
2472 if (!mod) {
2473 if (is_vmlinux(modname))
2474 have_vmlinux = 1;
2475 mod = new_module(modname);
2476 mod->skip = 1;
2477 }
2478 s = sym_add_exported(symname, mod, export_no(export));
2479 s->kernel = kernel;
2480 s->preloaded = 1;
2481 s->is_static = 0;
2482 sym_update_crc(symname, mod, crc, export_no(export));
2483 sym_update_namespace(symname, namespace);
2484 }
2485 release_file(file, size);
2486 return;
2487fail:
2488 release_file(file, size);
2489 fatal("parse error in symbol dump file\n");
2490}
2491
2492/* For normal builds always dump all symbols.
2493 * For external modules only dump symbols
2494 * that are not read from kernel Module.symvers.
2495 **/
2496static int dump_sym(struct symbol *sym)
2497{
2498 if (!external_module)
2499 return 1;
2500 if (sym->vmlinux || sym->kernel)
2501 return 0;
2502 return 1;
2503}
2504
2505static void write_dump(const char *fname)
2506{
2507 struct buffer buf = { };
2508 struct symbol *symbol;
2509 const char *namespace;
2510 int n;
2511
2512 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2513 symbol = symbolhash[n];
2514 while (symbol) {
2515 if (dump_sym(symbol)) {
2516 namespace = symbol->namespace;
2517 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
2518 symbol->crc, symbol->name,
2519 namespace ? namespace : "",
2520 symbol->module->name,
2521 export_str(symbol->export));
2522 }
2523 symbol = symbol->next;
2524 }
2525 }
2526 write_if_changed(&buf, fname);
2527 free(buf.p);
2528}
2529
2530static void write_namespace_deps_files(void)
2531{
2532 struct module *mod;
2533 struct namespace_list *ns;
2534 struct buffer ns_deps_buf = {};
2535
2536 for (mod = modules; mod; mod = mod->next) {
2537 char fname[PATH_MAX];
2538
2539 if (mod->skip)
2540 continue;
2541
2542 ns_deps_buf.pos = 0;
2543
2544 for (ns = mod->required_namespaces; ns; ns = ns->next)
2545 buf_printf(&ns_deps_buf, "%s\n", ns->namespace);
2546
2547 if (ns_deps_buf.pos == 0)
2548 continue;
2549
2550 sprintf(fname, "%s.ns_deps", mod->name);
2551 write_if_changed(&ns_deps_buf, fname);
2552 }
2553}
2554
2555struct ext_sym_list {
2556 struct ext_sym_list *next;
2557 const char *file;
2558};
2559
2560int main(int argc, char **argv)
2561{
2562 struct module *mod;
2563 struct buffer buf = { };
2564 char *kernel_read = NULL, *module_read = NULL;
2565 char *dump_write = NULL, *files_source = NULL;
2566 int opt;
2567 int err;
2568 int n;
2569 struct ext_sym_list *extsym_iter;
2570 struct ext_sym_list *extsym_start = NULL;
2571
2572 while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awEd")) != -1) {
2573 switch (opt) {
2574 case 'i':
2575 kernel_read = optarg;
2576 break;
2577 case 'I':
2578 module_read = optarg;
2579 external_module = 1;
2580 break;
2581 case 'e':
2582 external_module = 1;
2583 extsym_iter =
2584 NOFAIL(malloc(sizeof(*extsym_iter)));
2585 extsym_iter->next = extsym_start;
2586 extsym_iter->file = optarg;
2587 extsym_start = extsym_iter;
2588 break;
2589 case 'm':
2590 modversions = 1;
2591 break;
2592 case 'n':
2593 ignore_missing_files = 1;
2594 break;
2595 case 'o':
2596 dump_write = optarg;
2597 break;
2598 case 'a':
2599 all_versions = 1;
2600 break;
2601 case 's':
2602 vmlinux_section_warnings = 0;
2603 break;
2604 case 'T':
2605 files_source = optarg;
2606 break;
2607 case 'w':
2608 warn_unresolved = 1;
2609 break;
2610 case 'E':
2611 sec_mismatch_fatal = 1;
2612 break;
2613 case 'd':
2614 write_namespace_deps = 1;
2615 break;
2616 default:
2617 exit(1);
2618 }
2619 }
2620
2621 if (kernel_read)
2622 read_dump(kernel_read, 1);
2623 if (module_read)
2624 read_dump(module_read, 0);
2625 while (extsym_start) {
2626 read_dump(extsym_start->file, 0);
2627 extsym_iter = extsym_start->next;
2628 free(extsym_start);
2629 extsym_start = extsym_iter;
2630 }
2631
2632 while (optind < argc)
2633 read_symbols(argv[optind++]);
2634
2635 if (files_source)
2636 read_symbols_from_files(files_source);
2637
2638 err = 0;
2639
2640 for (mod = modules; mod; mod = mod->next) {
2641 char fname[PATH_MAX];
2642
2643 if (mod->skip)
2644 continue;
2645
2646 buf.pos = 0;
2647
2648 err |= check_modname_len(mod);
2649 err |= check_exports(mod);
2650 if (write_namespace_deps)
2651 continue;
2652
2653 add_header(&buf, mod);
2654 add_intree_flag(&buf, !external_module);
2655 add_retpoline(&buf);
2656 add_staging_flag(&buf, mod->name);
2657 err |= add_versions(&buf, mod);
2658 add_depends(&buf, mod);
2659 add_moddevtable(&buf, mod);
2660 add_srcversion(&buf, mod);
2661
2662 sprintf(fname, "%s.mod.c", mod->name);
2663 write_if_changed(&buf, fname);
2664 }
2665
2666 if (write_namespace_deps) {
2667 write_namespace_deps_files();
2668 return 0;
2669 }
2670
2671 if (dump_write)
2672 write_dump(dump_write);
2673 if (sec_mismatch_count && sec_mismatch_fatal)
2674 fatal("modpost: Section mismatches detected.\n"
2675 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2676 for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
2677 struct symbol *s;
2678
2679 for (s = symbolhash[n]; s; s = s->next) {
2680 /*
2681 * Do not check "vmlinux". This avoids the same warnings
2682 * shown twice, and false-positives for ARCH=um.
2683 */
2684 if (is_vmlinux(s->module->name) && !s->module->is_dot_o)
2685 continue;
2686
2687 if (s->is_static)
2688 warn("\"%s\" [%s] is a static %s\n",
2689 s->name, s->module->name,
2690 export_str(s->export));
2691 }
2692 }
2693
2694 free(buf.p);
2695
2696 return err;
2697}
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}