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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/generated/autoconf.h"
23#include "../../include/linux/license.h"
24#include "../../include/linux/export.h"
25
26/* Are we using CONFIG_MODVERSIONS? */
27static int modversions = 0;
28/* Warn about undefined symbols? (do so if we have vmlinux) */
29static int have_vmlinux = 0;
30/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
31static int all_versions = 0;
32/* If we are modposting external module set to 1 */
33static int external_module = 0;
34/* Warn about section mismatch in vmlinux if set to 1 */
35static int vmlinux_section_warnings = 1;
36/* Only warn about unresolved symbols */
37static int warn_unresolved = 0;
38/* How a symbol is exported */
39static int sec_mismatch_count = 0;
40static int sec_mismatch_verbose = 1;
41static int sec_mismatch_fatal = 0;
42/* ignore missing files */
43static int ignore_missing_files;
44
45enum export {
46 export_plain, export_unused, export_gpl,
47 export_unused_gpl, export_gpl_future, export_unknown
48};
49
50/* In kernel, this size is defined in linux/module.h;
51 * here we use Elf_Addr instead of long for covering cross-compile
52 */
53
54#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
55
56#define PRINTF __attribute__ ((format (printf, 1, 2)))
57
58PRINTF void fatal(const char *fmt, ...)
59{
60 va_list arglist;
61
62 fprintf(stderr, "FATAL: ");
63
64 va_start(arglist, fmt);
65 vfprintf(stderr, fmt, arglist);
66 va_end(arglist);
67
68 exit(1);
69}
70
71PRINTF void warn(const char *fmt, ...)
72{
73 va_list arglist;
74
75 fprintf(stderr, "WARNING: ");
76
77 va_start(arglist, fmt);
78 vfprintf(stderr, fmt, arglist);
79 va_end(arglist);
80}
81
82PRINTF void merror(const char *fmt, ...)
83{
84 va_list arglist;
85
86 fprintf(stderr, "ERROR: ");
87
88 va_start(arglist, fmt);
89 vfprintf(stderr, fmt, arglist);
90 va_end(arglist);
91}
92
93static inline bool strends(const char *str, const char *postfix)
94{
95 if (strlen(str) < strlen(postfix))
96 return false;
97
98 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
99}
100
101static int is_vmlinux(const char *modname)
102{
103 const char *myname;
104
105 myname = strrchr(modname, '/');
106 if (myname)
107 myname++;
108 else
109 myname = modname;
110
111 return (strcmp(myname, "vmlinux") == 0) ||
112 (strcmp(myname, "vmlinux.o") == 0);
113}
114
115void *do_nofail(void *ptr, const char *expr)
116{
117 if (!ptr)
118 fatal("modpost: Memory allocation failure: %s.\n", expr);
119
120 return ptr;
121}
122
123/* A list of all modules we processed */
124static struct module *modules;
125
126static struct module *find_module(char *modname)
127{
128 struct module *mod;
129
130 for (mod = modules; mod; mod = mod->next)
131 if (strcmp(mod->name, modname) == 0)
132 break;
133 return mod;
134}
135
136static struct module *new_module(const char *modname)
137{
138 struct module *mod;
139 char *p;
140
141 mod = NOFAIL(malloc(sizeof(*mod)));
142 memset(mod, 0, sizeof(*mod));
143 p = NOFAIL(strdup(modname));
144
145 /* strip trailing .o */
146 if (strends(p, ".o")) {
147 p[strlen(p) - 2] = '\0';
148 mod->is_dot_o = 1;
149 }
150
151 /* add to list */
152 mod->name = p;
153 mod->gpl_compatible = -1;
154 mod->next = modules;
155 modules = mod;
156
157 return mod;
158}
159
160/* A hash of all exported symbols,
161 * struct symbol is also used for lists of unresolved symbols */
162
163#define SYMBOL_HASH_SIZE 1024
164
165struct symbol {
166 struct symbol *next;
167 struct module *module;
168 unsigned int crc;
169 int crc_valid;
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 enum export export; /* Type of export */
176 char name[0];
177};
178
179static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
180
181/* This is based on the hash agorithm from gdbm, via tdb */
182static inline unsigned int tdb_hash(const char *name)
183{
184 unsigned value; /* Used to compute the hash value. */
185 unsigned i; /* Used to cycle through random values. */
186
187 /* Set the initial value from the key size. */
188 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
189 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
190
191 return (1103515243 * value + 12345);
192}
193
194/**
195 * Allocate a new symbols for use in the hash of exported symbols or
196 * the list of unresolved symbols per module
197 **/
198static struct symbol *alloc_symbol(const char *name, unsigned int weak,
199 struct symbol *next)
200{
201 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
202
203 memset(s, 0, sizeof(*s));
204 strcpy(s->name, name);
205 s->weak = weak;
206 s->next = next;
207 return s;
208}
209
210/* For the hash of exported symbols */
211static struct symbol *new_symbol(const char *name, struct module *module,
212 enum export export)
213{
214 unsigned int hash;
215 struct symbol *new;
216
217 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
218 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
219 new->module = module;
220 new->export = export;
221 return new;
222}
223
224static struct symbol *find_symbol(const char *name)
225{
226 struct symbol *s;
227
228 /* For our purposes, .foo matches foo. PPC64 needs this. */
229 if (name[0] == '.')
230 name++;
231
232 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
233 if (strcmp(s->name, name) == 0)
234 return s;
235 }
236 return NULL;
237}
238
239static const struct {
240 const char *str;
241 enum export export;
242} export_list[] = {
243 { .str = "EXPORT_SYMBOL", .export = export_plain },
244 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
245 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
246 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
247 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
248 { .str = "(unknown)", .export = export_unknown },
249};
250
251
252static const char *export_str(enum export ex)
253{
254 return export_list[ex].str;
255}
256
257static enum export export_no(const char *s)
258{
259 int i;
260
261 if (!s)
262 return export_unknown;
263 for (i = 0; export_list[i].export != export_unknown; i++) {
264 if (strcmp(export_list[i].str, s) == 0)
265 return export_list[i].export;
266 }
267 return export_unknown;
268}
269
270static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
271{
272 return (void *)elf->hdr +
273 elf->sechdrs[elf->secindex_strings].sh_offset +
274 sechdr->sh_name;
275}
276
277static const char *sec_name(struct elf_info *elf, int secindex)
278{
279 return sech_name(elf, &elf->sechdrs[secindex]);
280}
281
282#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
283
284static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
285{
286 const char *secname = sec_name(elf, sec);
287
288 if (strstarts(secname, "___ksymtab+"))
289 return export_plain;
290 else if (strstarts(secname, "___ksymtab_unused+"))
291 return export_unused;
292 else if (strstarts(secname, "___ksymtab_gpl+"))
293 return export_gpl;
294 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
295 return export_unused_gpl;
296 else if (strstarts(secname, "___ksymtab_gpl_future+"))
297 return export_gpl_future;
298 else
299 return export_unknown;
300}
301
302static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
303{
304 if (sec == elf->export_sec)
305 return export_plain;
306 else if (sec == elf->export_unused_sec)
307 return export_unused;
308 else if (sec == elf->export_gpl_sec)
309 return export_gpl;
310 else if (sec == elf->export_unused_gpl_sec)
311 return export_unused_gpl;
312 else if (sec == elf->export_gpl_future_sec)
313 return export_gpl_future;
314 else
315 return export_unknown;
316}
317
318/**
319 * Add an exported symbol - it may have already been added without a
320 * CRC, in this case just update the CRC
321 **/
322static struct symbol *sym_add_exported(const char *name, struct module *mod,
323 enum export export)
324{
325 struct symbol *s = find_symbol(name);
326
327 if (!s) {
328 s = new_symbol(name, mod, export);
329 } else {
330 if (!s->preloaded) {
331 warn("%s: '%s' exported twice. Previous export "
332 "was in %s%s\n", mod->name, name,
333 s->module->name,
334 is_vmlinux(s->module->name) ?"":".ko");
335 } else {
336 /* In case Module.symvers was out of date */
337 s->module = mod;
338 }
339 }
340 s->preloaded = 0;
341 s->vmlinux = is_vmlinux(mod->name);
342 s->kernel = 0;
343 s->export = export;
344 return s;
345}
346
347static void sym_update_crc(const char *name, struct module *mod,
348 unsigned int crc, enum export export)
349{
350 struct symbol *s = find_symbol(name);
351
352 if (!s) {
353 s = new_symbol(name, mod, export);
354 /* Don't complain when we find it later. */
355 s->preloaded = 1;
356 }
357 s->crc = crc;
358 s->crc_valid = 1;
359}
360
361void *grab_file(const char *filename, unsigned long *size)
362{
363 struct stat st;
364 void *map = MAP_FAILED;
365 int fd;
366
367 fd = open(filename, O_RDONLY);
368 if (fd < 0)
369 return NULL;
370 if (fstat(fd, &st))
371 goto failed;
372
373 *size = st.st_size;
374 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
375
376failed:
377 close(fd);
378 if (map == MAP_FAILED)
379 return NULL;
380 return map;
381}
382
383/**
384 * Return a copy of the next line in a mmap'ed file.
385 * spaces in the beginning of the line is trimmed away.
386 * Return a pointer to a static buffer.
387 **/
388char *get_next_line(unsigned long *pos, void *file, unsigned long size)
389{
390 static char line[4096];
391 int skip = 1;
392 size_t len = 0;
393 signed char *p = (signed char *)file + *pos;
394 char *s = line;
395
396 for (; *pos < size ; (*pos)++) {
397 if (skip && isspace(*p)) {
398 p++;
399 continue;
400 }
401 skip = 0;
402 if (*p != '\n' && (*pos < size)) {
403 len++;
404 *s++ = *p++;
405 if (len > 4095)
406 break; /* Too long, stop */
407 } else {
408 /* End of string */
409 *s = '\0';
410 return line;
411 }
412 }
413 /* End of buffer */
414 return NULL;
415}
416
417void release_file(void *file, unsigned long size)
418{
419 munmap(file, size);
420}
421
422static int parse_elf(struct elf_info *info, const char *filename)
423{
424 unsigned int i;
425 Elf_Ehdr *hdr;
426 Elf_Shdr *sechdrs;
427 Elf_Sym *sym;
428 const char *secstrings;
429 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
430
431 hdr = grab_file(filename, &info->size);
432 if (!hdr) {
433 if (ignore_missing_files) {
434 fprintf(stderr, "%s: %s (ignored)\n", filename,
435 strerror(errno));
436 return 0;
437 }
438 perror(filename);
439 exit(1);
440 }
441 info->hdr = hdr;
442 if (info->size < sizeof(*hdr)) {
443 /* file too small, assume this is an empty .o file */
444 return 0;
445 }
446 /* Is this a valid ELF file? */
447 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
448 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
449 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
450 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
451 /* Not an ELF file - silently ignore it */
452 return 0;
453 }
454 /* Fix endianness in ELF header */
455 hdr->e_type = TO_NATIVE(hdr->e_type);
456 hdr->e_machine = TO_NATIVE(hdr->e_machine);
457 hdr->e_version = TO_NATIVE(hdr->e_version);
458 hdr->e_entry = TO_NATIVE(hdr->e_entry);
459 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
460 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
461 hdr->e_flags = TO_NATIVE(hdr->e_flags);
462 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
463 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
464 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
465 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
466 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
467 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
468 sechdrs = (void *)hdr + hdr->e_shoff;
469 info->sechdrs = sechdrs;
470
471 /* Check if file offset is correct */
472 if (hdr->e_shoff > info->size) {
473 fatal("section header offset=%lu in file '%s' is bigger than "
474 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
475 filename, info->size);
476 return 0;
477 }
478
479 if (hdr->e_shnum == SHN_UNDEF) {
480 /*
481 * There are more than 64k sections,
482 * read count from .sh_size.
483 */
484 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
485 }
486 else {
487 info->num_sections = hdr->e_shnum;
488 }
489 if (hdr->e_shstrndx == SHN_XINDEX) {
490 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
491 }
492 else {
493 info->secindex_strings = hdr->e_shstrndx;
494 }
495
496 /* Fix endianness in section headers */
497 for (i = 0; i < info->num_sections; i++) {
498 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
499 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
500 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
501 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
502 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
503 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
504 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
505 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
506 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
507 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
508 }
509 /* Find symbol table. */
510 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
511 for (i = 1; i < info->num_sections; i++) {
512 const char *secname;
513 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
514
515 if (!nobits && sechdrs[i].sh_offset > info->size) {
516 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
517 "sizeof(*hrd)=%zu\n", filename,
518 (unsigned long)sechdrs[i].sh_offset,
519 sizeof(*hdr));
520 return 0;
521 }
522 secname = secstrings + sechdrs[i].sh_name;
523 if (strcmp(secname, ".modinfo") == 0) {
524 if (nobits)
525 fatal("%s has NOBITS .modinfo\n", filename);
526 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
527 info->modinfo_len = sechdrs[i].sh_size;
528 } else if (strcmp(secname, "__ksymtab") == 0)
529 info->export_sec = i;
530 else if (strcmp(secname, "__ksymtab_unused") == 0)
531 info->export_unused_sec = i;
532 else if (strcmp(secname, "__ksymtab_gpl") == 0)
533 info->export_gpl_sec = i;
534 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
535 info->export_unused_gpl_sec = i;
536 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
537 info->export_gpl_future_sec = i;
538
539 if (sechdrs[i].sh_type == SHT_SYMTAB) {
540 unsigned int sh_link_idx;
541 symtab_idx = i;
542 info->symtab_start = (void *)hdr +
543 sechdrs[i].sh_offset;
544 info->symtab_stop = (void *)hdr +
545 sechdrs[i].sh_offset + sechdrs[i].sh_size;
546 sh_link_idx = sechdrs[i].sh_link;
547 info->strtab = (void *)hdr +
548 sechdrs[sh_link_idx].sh_offset;
549 }
550
551 /* 32bit section no. table? ("more than 64k sections") */
552 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
553 symtab_shndx_idx = i;
554 info->symtab_shndx_start = (void *)hdr +
555 sechdrs[i].sh_offset;
556 info->symtab_shndx_stop = (void *)hdr +
557 sechdrs[i].sh_offset + sechdrs[i].sh_size;
558 }
559 }
560 if (!info->symtab_start)
561 fatal("%s has no symtab?\n", filename);
562
563 /* Fix endianness in symbols */
564 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
565 sym->st_shndx = TO_NATIVE(sym->st_shndx);
566 sym->st_name = TO_NATIVE(sym->st_name);
567 sym->st_value = TO_NATIVE(sym->st_value);
568 sym->st_size = TO_NATIVE(sym->st_size);
569 }
570
571 if (symtab_shndx_idx != ~0U) {
572 Elf32_Word *p;
573 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
574 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
575 filename, sechdrs[symtab_shndx_idx].sh_link,
576 symtab_idx);
577 /* Fix endianness */
578 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
579 p++)
580 *p = TO_NATIVE(*p);
581 }
582
583 return 1;
584}
585
586static void parse_elf_finish(struct elf_info *info)
587{
588 release_file(info->hdr, info->size);
589}
590
591static int ignore_undef_symbol(struct elf_info *info, const char *symname)
592{
593 /* ignore __this_module, it will be resolved shortly */
594 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
595 return 1;
596 /* ignore global offset table */
597 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
598 return 1;
599 if (info->hdr->e_machine == EM_PPC)
600 /* Special register function linked on all modules during final link of .ko */
601 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
602 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
603 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
604 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
605 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
606 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
607 return 1;
608 if (info->hdr->e_machine == EM_PPC64)
609 /* Special register function linked on all modules during final link of .ko */
610 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
611 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
612 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
613 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
614 strcmp(symname, ".TOC.") == 0)
615 return 1;
616 /* Do not ignore this symbol */
617 return 0;
618}
619
620#define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
621#define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
622
623static void handle_modversions(struct module *mod, struct elf_info *info,
624 Elf_Sym *sym, const char *symname)
625{
626 unsigned int crc;
627 enum export export;
628 bool is_crc = false;
629
630 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
631 strncmp(symname, "__ksymtab", 9) == 0)
632 export = export_from_secname(info, get_secindex(info, sym));
633 else
634 export = export_from_sec(info, get_secindex(info, sym));
635
636 /* CRC'd symbol */
637 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
638 is_crc = true;
639 crc = (unsigned int) sym->st_value;
640 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
641 unsigned int *crcp;
642
643 /* symbol points to the CRC in the ELF object */
644 crcp = (void *)info->hdr + sym->st_value +
645 info->sechdrs[sym->st_shndx].sh_offset -
646 (info->hdr->e_type != ET_REL ?
647 info->sechdrs[sym->st_shndx].sh_addr : 0);
648 crc = *crcp;
649 }
650 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
651 export);
652 }
653
654 switch (sym->st_shndx) {
655 case SHN_COMMON:
656 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
657 /* Should warn here, but modpost runs before the linker */
658 } else
659 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
660 break;
661 case SHN_UNDEF:
662 /* undefined symbol */
663 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
664 ELF_ST_BIND(sym->st_info) != STB_WEAK)
665 break;
666 if (ignore_undef_symbol(info, symname))
667 break;
668/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
669#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
670/* add compatibility with older glibc */
671#ifndef STT_SPARC_REGISTER
672#define STT_SPARC_REGISTER STT_REGISTER
673#endif
674 if (info->hdr->e_machine == EM_SPARC ||
675 info->hdr->e_machine == EM_SPARCV9) {
676 /* Ignore register directives. */
677 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
678 break;
679 if (symname[0] == '.') {
680 char *munged = strdup(symname);
681 munged[0] = '_';
682 munged[1] = toupper(munged[1]);
683 symname = munged;
684 }
685 }
686#endif
687
688#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
689 if (symname[0] != '_')
690 break;
691 else
692 symname++;
693#endif
694 if (is_crc) {
695 const char *e = is_vmlinux(mod->name) ?"":".ko";
696 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
697 }
698 mod->unres = alloc_symbol(symname,
699 ELF_ST_BIND(sym->st_info) == STB_WEAK,
700 mod->unres);
701 break;
702 default:
703 /* All exported symbols */
704 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
705 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
706 export);
707 }
708 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
709 mod->has_init = 1;
710 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
711 mod->has_cleanup = 1;
712 break;
713 }
714}
715
716/**
717 * Parse tag=value strings from .modinfo section
718 **/
719static char *next_string(char *string, unsigned long *secsize)
720{
721 /* Skip non-zero chars */
722 while (string[0]) {
723 string++;
724 if ((*secsize)-- <= 1)
725 return NULL;
726 }
727
728 /* Skip any zero padding. */
729 while (!string[0]) {
730 string++;
731 if ((*secsize)-- <= 1)
732 return NULL;
733 }
734 return string;
735}
736
737static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
738 const char *tag, char *info)
739{
740 char *p;
741 unsigned int taglen = strlen(tag);
742 unsigned long size = modinfo_len;
743
744 if (info) {
745 size -= info - (char *)modinfo;
746 modinfo = next_string(info, &size);
747 }
748
749 for (p = modinfo; p; p = next_string(p, &size)) {
750 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
751 return p + taglen + 1;
752 }
753 return NULL;
754}
755
756static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
757 const char *tag)
758
759{
760 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
761}
762
763/**
764 * Test if string s ends in string sub
765 * return 0 if match
766 **/
767static int strrcmp(const char *s, const char *sub)
768{
769 int slen, sublen;
770
771 if (!s || !sub)
772 return 1;
773
774 slen = strlen(s);
775 sublen = strlen(sub);
776
777 if ((slen == 0) || (sublen == 0))
778 return 1;
779
780 if (sublen > slen)
781 return 1;
782
783 return memcmp(s + slen - sublen, sub, sublen);
784}
785
786static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
787{
788 if (sym)
789 return elf->strtab + sym->st_name;
790 else
791 return "(unknown)";
792}
793
794/* The pattern is an array of simple patterns.
795 * "foo" will match an exact string equal to "foo"
796 * "*foo" will match a string that ends with "foo"
797 * "foo*" will match a string that begins with "foo"
798 * "*foo*" will match a string that contains "foo"
799 */
800static int match(const char *sym, const char * const pat[])
801{
802 const char *p;
803 while (*pat) {
804 p = *pat++;
805 const char *endp = p + strlen(p) - 1;
806
807 /* "*foo*" */
808 if (*p == '*' && *endp == '*') {
809 char *here, *bare = strndup(p + 1, strlen(p) - 2);
810
811 here = strstr(sym, bare);
812 free(bare);
813 if (here != NULL)
814 return 1;
815 }
816 /* "*foo" */
817 else if (*p == '*') {
818 if (strrcmp(sym, p + 1) == 0)
819 return 1;
820 }
821 /* "foo*" */
822 else if (*endp == '*') {
823 if (strncmp(sym, p, strlen(p) - 1) == 0)
824 return 1;
825 }
826 /* no wildcards */
827 else {
828 if (strcmp(p, sym) == 0)
829 return 1;
830 }
831 }
832 /* no match */
833 return 0;
834}
835
836/* sections that we do not want to do full section mismatch check on */
837static const char *const section_white_list[] =
838{
839 ".comment*",
840 ".debug*",
841 ".cranges", /* sh64 */
842 ".zdebug*", /* Compressed debug sections. */
843 ".GCC.command.line", /* record-gcc-switches */
844 ".mdebug*", /* alpha, score, mips etc. */
845 ".pdr", /* alpha, score, mips etc. */
846 ".stab*",
847 ".note*",
848 ".got*",
849 ".toc*",
850 ".xt.prop", /* xtensa */
851 ".xt.lit", /* xtensa */
852 ".arcextmap*", /* arc */
853 ".gnu.linkonce.arcext*", /* arc : modules */
854 ".cmem*", /* EZchip */
855 ".fmt_slot*", /* EZchip */
856 ".gnu.lto*",
857 ".discard.*",
858 NULL
859};
860
861/*
862 * This is used to find sections missing the SHF_ALLOC flag.
863 * The cause of this is often a section specified in assembler
864 * without "ax" / "aw".
865 */
866static void check_section(const char *modname, struct elf_info *elf,
867 Elf_Shdr *sechdr)
868{
869 const char *sec = sech_name(elf, sechdr);
870
871 if (sechdr->sh_type == SHT_PROGBITS &&
872 !(sechdr->sh_flags & SHF_ALLOC) &&
873 !match(sec, section_white_list)) {
874 warn("%s (%s): unexpected non-allocatable section.\n"
875 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
876 "Note that for example <linux/init.h> contains\n"
877 "section definitions for use in .S files.\n\n",
878 modname, sec);
879 }
880}
881
882
883
884#define ALL_INIT_DATA_SECTIONS \
885 ".init.setup", ".init.rodata", ".meminit.rodata", \
886 ".init.data", ".meminit.data"
887#define ALL_EXIT_DATA_SECTIONS \
888 ".exit.data", ".memexit.data"
889
890#define ALL_INIT_TEXT_SECTIONS \
891 ".init.text", ".meminit.text"
892#define ALL_EXIT_TEXT_SECTIONS \
893 ".exit.text", ".memexit.text"
894
895#define ALL_PCI_INIT_SECTIONS \
896 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
897 ".pci_fixup_enable", ".pci_fixup_resume", \
898 ".pci_fixup_resume_early", ".pci_fixup_suspend"
899
900#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
901#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
902
903#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
904#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
905
906#define DATA_SECTIONS ".data", ".data.rel"
907#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
908 ".kprobes.text", ".cpuidle.text"
909#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
910 ".fixup", ".entry.text", ".exception.text", ".text.*", \
911 ".coldtext"
912
913#define INIT_SECTIONS ".init.*"
914#define MEM_INIT_SECTIONS ".meminit.*"
915
916#define EXIT_SECTIONS ".exit.*"
917#define MEM_EXIT_SECTIONS ".memexit.*"
918
919#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
920 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
921
922/* init data sections */
923static const char *const init_data_sections[] =
924 { ALL_INIT_DATA_SECTIONS, NULL };
925
926/* all init sections */
927static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
928
929/* All init and exit sections (code + data) */
930static const char *const init_exit_sections[] =
931 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
932
933/* all text sections */
934static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
935
936/* data section */
937static const char *const data_sections[] = { DATA_SECTIONS, NULL };
938
939
940/* symbols in .data that may refer to init/exit sections */
941#define DEFAULT_SYMBOL_WHITE_LIST \
942 "*driver", \
943 "*_template", /* scsi uses *_template a lot */ \
944 "*_timer", /* arm uses ops structures named _timer a lot */ \
945 "*_sht", /* scsi also used *_sht to some extent */ \
946 "*_ops", \
947 "*_probe", \
948 "*_probe_one", \
949 "*_console"
950
951static const char *const head_sections[] = { ".head.text*", NULL };
952static const char *const linker_symbols[] =
953 { "__init_begin", "_sinittext", "_einittext", NULL };
954static const char *const optim_symbols[] = { "*.constprop.*", NULL };
955
956enum mismatch {
957 TEXT_TO_ANY_INIT,
958 DATA_TO_ANY_INIT,
959 TEXT_TO_ANY_EXIT,
960 DATA_TO_ANY_EXIT,
961 XXXINIT_TO_SOME_INIT,
962 XXXEXIT_TO_SOME_EXIT,
963 ANY_INIT_TO_ANY_EXIT,
964 ANY_EXIT_TO_ANY_INIT,
965 EXPORT_TO_INIT_EXIT,
966 EXTABLE_TO_NON_TEXT,
967};
968
969/**
970 * Describe how to match sections on different criterias:
971 *
972 * @fromsec: Array of sections to be matched.
973 *
974 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
975 * this array is forbidden (black-list). Can be empty.
976 *
977 * @good_tosec: Relocations applied to a section in @fromsec must be
978 * targetting sections in this array (white-list). Can be empty.
979 *
980 * @mismatch: Type of mismatch.
981 *
982 * @symbol_white_list: Do not match a relocation to a symbol in this list
983 * even if it is targetting a section in @bad_to_sec.
984 *
985 * @handler: Specific handler to call when a match is found. If NULL,
986 * default_mismatch_handler() will be called.
987 *
988 */
989struct sectioncheck {
990 const char *fromsec[20];
991 const char *bad_tosec[20];
992 const char *good_tosec[20];
993 enum mismatch mismatch;
994 const char *symbol_white_list[20];
995 void (*handler)(const char *modname, struct elf_info *elf,
996 const struct sectioncheck* const mismatch,
997 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
998
999};
1000
1001static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1002 const struct sectioncheck* const mismatch,
1003 Elf_Rela *r, Elf_Sym *sym,
1004 const char *fromsec);
1005
1006static const struct sectioncheck sectioncheck[] = {
1007/* Do not reference init/exit code/data from
1008 * normal code and data
1009 */
1010{
1011 .fromsec = { TEXT_SECTIONS, NULL },
1012 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1013 .mismatch = TEXT_TO_ANY_INIT,
1014 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1015},
1016{
1017 .fromsec = { DATA_SECTIONS, NULL },
1018 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1019 .mismatch = DATA_TO_ANY_INIT,
1020 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1021},
1022{
1023 .fromsec = { DATA_SECTIONS, NULL },
1024 .bad_tosec = { INIT_SECTIONS, NULL },
1025 .mismatch = DATA_TO_ANY_INIT,
1026 .symbol_white_list = {
1027 "*_template", "*_timer", "*_sht", "*_ops",
1028 "*_probe", "*_probe_one", "*_console", NULL
1029 },
1030},
1031{
1032 .fromsec = { TEXT_SECTIONS, NULL },
1033 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1034 .mismatch = TEXT_TO_ANY_EXIT,
1035 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1036},
1037{
1038 .fromsec = { DATA_SECTIONS, NULL },
1039 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1040 .mismatch = DATA_TO_ANY_EXIT,
1041 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1042},
1043/* Do not reference init code/data from meminit code/data */
1044{
1045 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1046 .bad_tosec = { INIT_SECTIONS, NULL },
1047 .mismatch = XXXINIT_TO_SOME_INIT,
1048 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1049},
1050/* Do not reference exit code/data from memexit code/data */
1051{
1052 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1053 .bad_tosec = { EXIT_SECTIONS, NULL },
1054 .mismatch = XXXEXIT_TO_SOME_EXIT,
1055 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1056},
1057/* Do not use exit code/data from init code */
1058{
1059 .fromsec = { ALL_INIT_SECTIONS, NULL },
1060 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1061 .mismatch = ANY_INIT_TO_ANY_EXIT,
1062 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1063},
1064/* Do not use init code/data from exit code */
1065{
1066 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1067 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1068 .mismatch = ANY_EXIT_TO_ANY_INIT,
1069 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1070},
1071{
1072 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1073 .bad_tosec = { INIT_SECTIONS, NULL },
1074 .mismatch = ANY_INIT_TO_ANY_EXIT,
1075 .symbol_white_list = { NULL },
1076},
1077/* Do not export init/exit functions or data */
1078{
1079 .fromsec = { "__ksymtab*", NULL },
1080 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1081 .mismatch = EXPORT_TO_INIT_EXIT,
1082 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1083},
1084{
1085 .fromsec = { "__ex_table", NULL },
1086 /* If you're adding any new black-listed sections in here, consider
1087 * adding a special 'printer' for them in scripts/check_extable.
1088 */
1089 .bad_tosec = { ".altinstr_replacement", NULL },
1090 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1091 .mismatch = EXTABLE_TO_NON_TEXT,
1092 .handler = extable_mismatch_handler,
1093}
1094};
1095
1096static const struct sectioncheck *section_mismatch(
1097 const char *fromsec, const char *tosec)
1098{
1099 int i;
1100 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1101 const struct sectioncheck *check = §ioncheck[0];
1102
1103 /*
1104 * The target section could be the SHT_NUL section when we're
1105 * handling relocations to un-resolved symbols, trying to match it
1106 * doesn't make much sense and causes build failures on parisc
1107 * architectures.
1108 */
1109 if (*tosec == '\0')
1110 return NULL;
1111
1112 for (i = 0; i < elems; i++) {
1113 if (match(fromsec, check->fromsec)) {
1114 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1115 return check;
1116 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1117 return check;
1118 }
1119 check++;
1120 }
1121 return NULL;
1122}
1123
1124/**
1125 * Whitelist to allow certain references to pass with no warning.
1126 *
1127 * Pattern 1:
1128 * If a module parameter is declared __initdata and permissions=0
1129 * then this is legal despite the warning generated.
1130 * We cannot see value of permissions here, so just ignore
1131 * this pattern.
1132 * The pattern is identified by:
1133 * tosec = .init.data
1134 * fromsec = .data*
1135 * atsym =__param*
1136 *
1137 * Pattern 1a:
1138 * module_param_call() ops can refer to __init set function if permissions=0
1139 * The pattern is identified by:
1140 * tosec = .init.text
1141 * fromsec = .data*
1142 * atsym = __param_ops_*
1143 *
1144 * Pattern 2:
1145 * Many drivers utilise a *driver container with references to
1146 * add, remove, probe functions etc.
1147 * the pattern is identified by:
1148 * tosec = init or exit section
1149 * fromsec = data section
1150 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1151 * *probe_one, *_console, *_timer
1152 *
1153 * Pattern 3:
1154 * Whitelist all references from .head.text to any init section
1155 *
1156 * Pattern 4:
1157 * Some symbols belong to init section but still it is ok to reference
1158 * these from non-init sections as these symbols don't have any memory
1159 * allocated for them and symbol address and value are same. So even
1160 * if init section is freed, its ok to reference those symbols.
1161 * For ex. symbols marking the init section boundaries.
1162 * This pattern is identified by
1163 * refsymname = __init_begin, _sinittext, _einittext
1164 *
1165 * Pattern 5:
1166 * GCC may optimize static inlines when fed constant arg(s) resulting
1167 * in functions like cpumask_empty() -- generating an associated symbol
1168 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1169 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1170 * meaningless section warning. May need to add isra symbols too...
1171 * This pattern is identified by
1172 * tosec = init section
1173 * fromsec = text section
1174 * refsymname = *.constprop.*
1175 *
1176 **/
1177static int secref_whitelist(const struct sectioncheck *mismatch,
1178 const char *fromsec, const char *fromsym,
1179 const char *tosec, const char *tosym)
1180{
1181 /* Check for pattern 1 */
1182 if (match(tosec, init_data_sections) &&
1183 match(fromsec, data_sections) &&
1184 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1185 return 0;
1186
1187 /* Check for pattern 1a */
1188 if (strcmp(tosec, ".init.text") == 0 &&
1189 match(fromsec, data_sections) &&
1190 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1191 return 0;
1192
1193 /* Check for pattern 2 */
1194 if (match(tosec, init_exit_sections) &&
1195 match(fromsec, data_sections) &&
1196 match(fromsym, mismatch->symbol_white_list))
1197 return 0;
1198
1199 /* Check for pattern 3 */
1200 if (match(fromsec, head_sections) &&
1201 match(tosec, init_sections))
1202 return 0;
1203
1204 /* Check for pattern 4 */
1205 if (match(tosym, linker_symbols))
1206 return 0;
1207
1208 /* Check for pattern 5 */
1209 if (match(fromsec, text_sections) &&
1210 match(tosec, init_sections) &&
1211 match(fromsym, optim_symbols))
1212 return 0;
1213
1214 return 1;
1215}
1216
1217/**
1218 * Find symbol based on relocation record info.
1219 * In some cases the symbol supplied is a valid symbol so
1220 * return refsym. If st_name != 0 we assume this is a valid symbol.
1221 * In other cases the symbol needs to be looked up in the symbol table
1222 * based on section and address.
1223 * **/
1224static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1225 Elf_Sym *relsym)
1226{
1227 Elf_Sym *sym;
1228 Elf_Sym *near = NULL;
1229 Elf64_Sword distance = 20;
1230 Elf64_Sword d;
1231 unsigned int relsym_secindex;
1232
1233 if (relsym->st_name != 0)
1234 return relsym;
1235
1236 relsym_secindex = get_secindex(elf, relsym);
1237 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1238 if (get_secindex(elf, sym) != relsym_secindex)
1239 continue;
1240 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1241 continue;
1242 if (sym->st_value == addr)
1243 return sym;
1244 /* Find a symbol nearby - addr are maybe negative */
1245 d = sym->st_value - addr;
1246 if (d < 0)
1247 d = addr - sym->st_value;
1248 if (d < distance) {
1249 distance = d;
1250 near = sym;
1251 }
1252 }
1253 /* We need a close match */
1254 if (distance < 20)
1255 return near;
1256 else
1257 return NULL;
1258}
1259
1260static inline int is_arm_mapping_symbol(const char *str)
1261{
1262 return str[0] == '$' && strchr("axtd", str[1])
1263 && (str[2] == '\0' || str[2] == '.');
1264}
1265
1266/*
1267 * If there's no name there, ignore it; likewise, ignore it if it's
1268 * one of the magic symbols emitted used by current ARM tools.
1269 *
1270 * Otherwise if find_symbols_between() returns those symbols, they'll
1271 * fail the whitelist tests and cause lots of false alarms ... fixable
1272 * only by merging __exit and __init sections into __text, bloating
1273 * the kernel (which is especially evil on embedded platforms).
1274 */
1275static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1276{
1277 const char *name = elf->strtab + sym->st_name;
1278
1279 if (!name || !strlen(name))
1280 return 0;
1281 return !is_arm_mapping_symbol(name);
1282}
1283
1284/*
1285 * Find symbols before or equal addr and after addr - in the section sec.
1286 * If we find two symbols with equal offset prefer one with a valid name.
1287 * The ELF format may have a better way to detect what type of symbol
1288 * it is, but this works for now.
1289 **/
1290static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1291 const char *sec)
1292{
1293 Elf_Sym *sym;
1294 Elf_Sym *near = NULL;
1295 Elf_Addr distance = ~0;
1296
1297 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1298 const char *symsec;
1299
1300 if (is_shndx_special(sym->st_shndx))
1301 continue;
1302 symsec = sec_name(elf, get_secindex(elf, sym));
1303 if (strcmp(symsec, sec) != 0)
1304 continue;
1305 if (!is_valid_name(elf, sym))
1306 continue;
1307 if (sym->st_value <= addr) {
1308 if ((addr - sym->st_value) < distance) {
1309 distance = addr - sym->st_value;
1310 near = sym;
1311 } else if ((addr - sym->st_value) == distance) {
1312 near = sym;
1313 }
1314 }
1315 }
1316 return near;
1317}
1318
1319/*
1320 * Convert a section name to the function/data attribute
1321 * .init.text => __init
1322 * .memexitconst => __memconst
1323 * etc.
1324 *
1325 * The memory of returned value has been allocated on a heap. The user of this
1326 * method should free it after usage.
1327*/
1328static char *sec2annotation(const char *s)
1329{
1330 if (match(s, init_exit_sections)) {
1331 char *p = malloc(20);
1332 char *r = p;
1333
1334 *p++ = '_';
1335 *p++ = '_';
1336 if (*s == '.')
1337 s++;
1338 while (*s && *s != '.')
1339 *p++ = *s++;
1340 *p = '\0';
1341 if (*s == '.')
1342 s++;
1343 if (strstr(s, "rodata") != NULL)
1344 strcat(p, "const ");
1345 else if (strstr(s, "data") != NULL)
1346 strcat(p, "data ");
1347 else
1348 strcat(p, " ");
1349 return r;
1350 } else {
1351 return strdup("");
1352 }
1353}
1354
1355static int is_function(Elf_Sym *sym)
1356{
1357 if (sym)
1358 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1359 else
1360 return -1;
1361}
1362
1363static void print_section_list(const char * const list[20])
1364{
1365 const char *const *s = list;
1366
1367 while (*s) {
1368 fprintf(stderr, "%s", *s);
1369 s++;
1370 if (*s)
1371 fprintf(stderr, ", ");
1372 }
1373 fprintf(stderr, "\n");
1374}
1375
1376static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1377{
1378 switch (is_func) {
1379 case 0: *name = "variable"; *name_p = ""; break;
1380 case 1: *name = "function"; *name_p = "()"; break;
1381 default: *name = "(unknown reference)"; *name_p = ""; break;
1382 }
1383}
1384
1385/*
1386 * Print a warning about a section mismatch.
1387 * Try to find symbols near it so user can find it.
1388 * Check whitelist before warning - it may be a false positive.
1389 */
1390static void report_sec_mismatch(const char *modname,
1391 const struct sectioncheck *mismatch,
1392 const char *fromsec,
1393 unsigned long long fromaddr,
1394 const char *fromsym,
1395 int from_is_func,
1396 const char *tosec, const char *tosym,
1397 int to_is_func)
1398{
1399 const char *from, *from_p;
1400 const char *to, *to_p;
1401 char *prl_from;
1402 char *prl_to;
1403
1404 sec_mismatch_count++;
1405 if (!sec_mismatch_verbose)
1406 return;
1407
1408 get_pretty_name(from_is_func, &from, &from_p);
1409 get_pretty_name(to_is_func, &to, &to_p);
1410
1411 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1412 "to the %s %s:%s%s\n",
1413 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1414 tosym, to_p);
1415
1416 switch (mismatch->mismatch) {
1417 case TEXT_TO_ANY_INIT:
1418 prl_from = sec2annotation(fromsec);
1419 prl_to = sec2annotation(tosec);
1420 fprintf(stderr,
1421 "The function %s%s() references\n"
1422 "the %s %s%s%s.\n"
1423 "This is often because %s lacks a %s\n"
1424 "annotation or the annotation of %s is wrong.\n",
1425 prl_from, fromsym,
1426 to, prl_to, tosym, to_p,
1427 fromsym, prl_to, tosym);
1428 free(prl_from);
1429 free(prl_to);
1430 break;
1431 case DATA_TO_ANY_INIT: {
1432 prl_to = sec2annotation(tosec);
1433 fprintf(stderr,
1434 "The variable %s references\n"
1435 "the %s %s%s%s\n"
1436 "If the reference is valid then annotate the\n"
1437 "variable with __init* or __refdata (see linux/init.h) "
1438 "or name the variable:\n",
1439 fromsym, to, prl_to, tosym, to_p);
1440 print_section_list(mismatch->symbol_white_list);
1441 free(prl_to);
1442 break;
1443 }
1444 case TEXT_TO_ANY_EXIT:
1445 prl_to = sec2annotation(tosec);
1446 fprintf(stderr,
1447 "The function %s() references a %s in an exit section.\n"
1448 "Often the %s %s%s has valid usage outside the exit section\n"
1449 "and the fix is to remove the %sannotation of %s.\n",
1450 fromsym, to, to, tosym, to_p, prl_to, tosym);
1451 free(prl_to);
1452 break;
1453 case DATA_TO_ANY_EXIT: {
1454 prl_to = sec2annotation(tosec);
1455 fprintf(stderr,
1456 "The variable %s references\n"
1457 "the %s %s%s%s\n"
1458 "If the reference is valid then annotate the\n"
1459 "variable with __exit* (see linux/init.h) or "
1460 "name the variable:\n",
1461 fromsym, to, prl_to, tosym, to_p);
1462 print_section_list(mismatch->symbol_white_list);
1463 free(prl_to);
1464 break;
1465 }
1466 case XXXINIT_TO_SOME_INIT:
1467 case XXXEXIT_TO_SOME_EXIT:
1468 prl_from = sec2annotation(fromsec);
1469 prl_to = sec2annotation(tosec);
1470 fprintf(stderr,
1471 "The %s %s%s%s references\n"
1472 "a %s %s%s%s.\n"
1473 "If %s is only used by %s then\n"
1474 "annotate %s with a matching annotation.\n",
1475 from, prl_from, fromsym, from_p,
1476 to, prl_to, tosym, to_p,
1477 tosym, fromsym, tosym);
1478 free(prl_from);
1479 free(prl_to);
1480 break;
1481 case ANY_INIT_TO_ANY_EXIT:
1482 prl_from = sec2annotation(fromsec);
1483 prl_to = sec2annotation(tosec);
1484 fprintf(stderr,
1485 "The %s %s%s%s references\n"
1486 "a %s %s%s%s.\n"
1487 "This is often seen when error handling "
1488 "in the init function\n"
1489 "uses functionality in the exit path.\n"
1490 "The fix is often to remove the %sannotation of\n"
1491 "%s%s so it may be used outside an exit section.\n",
1492 from, prl_from, fromsym, from_p,
1493 to, prl_to, tosym, to_p,
1494 prl_to, tosym, to_p);
1495 free(prl_from);
1496 free(prl_to);
1497 break;
1498 case ANY_EXIT_TO_ANY_INIT:
1499 prl_from = sec2annotation(fromsec);
1500 prl_to = sec2annotation(tosec);
1501 fprintf(stderr,
1502 "The %s %s%s%s references\n"
1503 "a %s %s%s%s.\n"
1504 "This is often seen when error handling "
1505 "in the exit function\n"
1506 "uses functionality in the init path.\n"
1507 "The fix is often to remove the %sannotation of\n"
1508 "%s%s so it may be used outside an init section.\n",
1509 from, prl_from, fromsym, from_p,
1510 to, prl_to, tosym, to_p,
1511 prl_to, tosym, to_p);
1512 free(prl_from);
1513 free(prl_to);
1514 break;
1515 case EXPORT_TO_INIT_EXIT:
1516 prl_to = sec2annotation(tosec);
1517 fprintf(stderr,
1518 "The symbol %s is exported and annotated %s\n"
1519 "Fix this by removing the %sannotation of %s "
1520 "or drop the export.\n",
1521 tosym, prl_to, prl_to, tosym);
1522 free(prl_to);
1523 break;
1524 case EXTABLE_TO_NON_TEXT:
1525 fatal("There's a special handler for this mismatch type, "
1526 "we should never get here.");
1527 break;
1528 }
1529 fprintf(stderr, "\n");
1530}
1531
1532static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1533 const struct sectioncheck* const mismatch,
1534 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1535{
1536 const char *tosec;
1537 Elf_Sym *to;
1538 Elf_Sym *from;
1539 const char *tosym;
1540 const char *fromsym;
1541
1542 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1543 fromsym = sym_name(elf, from);
1544
1545 if (!strncmp(fromsym, "reference___initcall",
1546 sizeof("reference___initcall")-1))
1547 return;
1548
1549 tosec = sec_name(elf, get_secindex(elf, sym));
1550 to = find_elf_symbol(elf, r->r_addend, sym);
1551 tosym = sym_name(elf, to);
1552
1553 /* check whitelist - we may ignore it */
1554 if (secref_whitelist(mismatch,
1555 fromsec, fromsym, tosec, tosym)) {
1556 report_sec_mismatch(modname, mismatch,
1557 fromsec, r->r_offset, fromsym,
1558 is_function(from), tosec, tosym,
1559 is_function(to));
1560 }
1561}
1562
1563static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1564{
1565 if (section_index > elf->num_sections)
1566 fatal("section_index is outside elf->num_sections!\n");
1567
1568 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1569}
1570
1571/*
1572 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1573 * to know the sizeof(struct exception_table_entry) for the target architecture.
1574 */
1575static unsigned int extable_entry_size = 0;
1576static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1577{
1578 /*
1579 * If we're currently checking the second relocation within __ex_table,
1580 * that relocation offset tells us the offsetof(struct
1581 * exception_table_entry, fixup) which is equal to sizeof(struct
1582 * exception_table_entry) divided by two. We use that to our advantage
1583 * since there's no portable way to get that size as every architecture
1584 * seems to go with different sized types. Not pretty but better than
1585 * hard-coding the size for every architecture..
1586 */
1587 if (!extable_entry_size)
1588 extable_entry_size = r->r_offset * 2;
1589}
1590
1591static inline bool is_extable_fault_address(Elf_Rela *r)
1592{
1593 /*
1594 * extable_entry_size is only discovered after we've handled the
1595 * _second_ relocation in __ex_table, so only abort when we're not
1596 * handling the first reloc and extable_entry_size is zero.
1597 */
1598 if (r->r_offset && extable_entry_size == 0)
1599 fatal("extable_entry size hasn't been discovered!\n");
1600
1601 return ((r->r_offset == 0) ||
1602 (r->r_offset % extable_entry_size == 0));
1603}
1604
1605#define is_second_extable_reloc(Start, Cur, Sec) \
1606 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1607
1608static void report_extable_warnings(const char* modname, struct elf_info* elf,
1609 const struct sectioncheck* const mismatch,
1610 Elf_Rela* r, Elf_Sym* sym,
1611 const char* fromsec, const char* tosec)
1612{
1613 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1614 const char* fromsym_name = sym_name(elf, fromsym);
1615 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1616 const char* tosym_name = sym_name(elf, tosym);
1617 const char* from_pretty_name;
1618 const char* from_pretty_name_p;
1619 const char* to_pretty_name;
1620 const char* to_pretty_name_p;
1621
1622 get_pretty_name(is_function(fromsym),
1623 &from_pretty_name, &from_pretty_name_p);
1624 get_pretty_name(is_function(tosym),
1625 &to_pretty_name, &to_pretty_name_p);
1626
1627 warn("%s(%s+0x%lx): Section mismatch in reference"
1628 " from the %s %s%s to the %s %s:%s%s\n",
1629 modname, fromsec, (long)r->r_offset, from_pretty_name,
1630 fromsym_name, from_pretty_name_p,
1631 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1632
1633 if (!match(tosec, mismatch->bad_tosec) &&
1634 is_executable_section(elf, get_secindex(elf, sym)))
1635 fprintf(stderr,
1636 "The relocation at %s+0x%lx references\n"
1637 "section \"%s\" which is not in the list of\n"
1638 "authorized sections. If you're adding a new section\n"
1639 "and/or if this reference is valid, add \"%s\" to the\n"
1640 "list of authorized sections to jump to on fault.\n"
1641 "This can be achieved by adding \"%s\" to \n"
1642 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1643 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1644}
1645
1646static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1647 const struct sectioncheck* const mismatch,
1648 Elf_Rela* r, Elf_Sym* sym,
1649 const char *fromsec)
1650{
1651 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1652
1653 sec_mismatch_count++;
1654
1655 if (sec_mismatch_verbose)
1656 report_extable_warnings(modname, elf, mismatch, r, sym,
1657 fromsec, tosec);
1658
1659 if (match(tosec, mismatch->bad_tosec))
1660 fatal("The relocation at %s+0x%lx references\n"
1661 "section \"%s\" which is black-listed.\n"
1662 "Something is seriously wrong and should be fixed.\n"
1663 "You might get more information about where this is\n"
1664 "coming from by using scripts/check_extable.sh %s\n",
1665 fromsec, (long)r->r_offset, tosec, modname);
1666 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1667 if (is_extable_fault_address(r))
1668 fatal("The relocation at %s+0x%lx references\n"
1669 "section \"%s\" which is not executable, IOW\n"
1670 "it is not possible for the kernel to fault\n"
1671 "at that address. Something is seriously wrong\n"
1672 "and should be fixed.\n",
1673 fromsec, (long)r->r_offset, tosec);
1674 else
1675 fatal("The relocation at %s+0x%lx references\n"
1676 "section \"%s\" which is not executable, IOW\n"
1677 "the kernel will fault if it ever tries to\n"
1678 "jump to it. Something is seriously wrong\n"
1679 "and should be fixed.\n",
1680 fromsec, (long)r->r_offset, tosec);
1681 }
1682}
1683
1684static void check_section_mismatch(const char *modname, struct elf_info *elf,
1685 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1686{
1687 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1688 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1689
1690 if (mismatch) {
1691 if (mismatch->handler)
1692 mismatch->handler(modname, elf, mismatch,
1693 r, sym, fromsec);
1694 else
1695 default_mismatch_handler(modname, elf, mismatch,
1696 r, sym, fromsec);
1697 }
1698}
1699
1700static unsigned int *reloc_location(struct elf_info *elf,
1701 Elf_Shdr *sechdr, Elf_Rela *r)
1702{
1703 Elf_Shdr *sechdrs = elf->sechdrs;
1704 int section = sechdr->sh_info;
1705
1706 return (void *)elf->hdr + sechdrs[section].sh_offset +
1707 r->r_offset;
1708}
1709
1710static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1711{
1712 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1713 unsigned int *location = reloc_location(elf, sechdr, r);
1714
1715 switch (r_typ) {
1716 case R_386_32:
1717 r->r_addend = TO_NATIVE(*location);
1718 break;
1719 case R_386_PC32:
1720 r->r_addend = TO_NATIVE(*location) + 4;
1721 /* For CONFIG_RELOCATABLE=y */
1722 if (elf->hdr->e_type == ET_EXEC)
1723 r->r_addend += r->r_offset;
1724 break;
1725 }
1726 return 0;
1727}
1728
1729#ifndef R_ARM_CALL
1730#define R_ARM_CALL 28
1731#endif
1732#ifndef R_ARM_JUMP24
1733#define R_ARM_JUMP24 29
1734#endif
1735
1736#ifndef R_ARM_THM_CALL
1737#define R_ARM_THM_CALL 10
1738#endif
1739#ifndef R_ARM_THM_JUMP24
1740#define R_ARM_THM_JUMP24 30
1741#endif
1742#ifndef R_ARM_THM_JUMP19
1743#define R_ARM_THM_JUMP19 51
1744#endif
1745
1746static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1747{
1748 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1749
1750 switch (r_typ) {
1751 case R_ARM_ABS32:
1752 /* From ARM ABI: (S + A) | T */
1753 r->r_addend = (int)(long)
1754 (elf->symtab_start + ELF_R_SYM(r->r_info));
1755 break;
1756 case R_ARM_PC24:
1757 case R_ARM_CALL:
1758 case R_ARM_JUMP24:
1759 case R_ARM_THM_CALL:
1760 case R_ARM_THM_JUMP24:
1761 case R_ARM_THM_JUMP19:
1762 /* From ARM ABI: ((S + A) | T) - P */
1763 r->r_addend = (int)(long)(elf->hdr +
1764 sechdr->sh_offset +
1765 (r->r_offset - sechdr->sh_addr));
1766 break;
1767 default:
1768 return 1;
1769 }
1770 return 0;
1771}
1772
1773static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1774{
1775 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1776 unsigned int *location = reloc_location(elf, sechdr, r);
1777 unsigned int inst;
1778
1779 if (r_typ == R_MIPS_HI16)
1780 return 1; /* skip this */
1781 inst = TO_NATIVE(*location);
1782 switch (r_typ) {
1783 case R_MIPS_LO16:
1784 r->r_addend = inst & 0xffff;
1785 break;
1786 case R_MIPS_26:
1787 r->r_addend = (inst & 0x03ffffff) << 2;
1788 break;
1789 case R_MIPS_32:
1790 r->r_addend = inst;
1791 break;
1792 }
1793 return 0;
1794}
1795
1796static void section_rela(const char *modname, struct elf_info *elf,
1797 Elf_Shdr *sechdr)
1798{
1799 Elf_Sym *sym;
1800 Elf_Rela *rela;
1801 Elf_Rela r;
1802 unsigned int r_sym;
1803 const char *fromsec;
1804
1805 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1806 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1807
1808 fromsec = sech_name(elf, sechdr);
1809 fromsec += strlen(".rela");
1810 /* if from section (name) is know good then skip it */
1811 if (match(fromsec, section_white_list))
1812 return;
1813
1814 for (rela = start; rela < stop; rela++) {
1815 r.r_offset = TO_NATIVE(rela->r_offset);
1816#if KERNEL_ELFCLASS == ELFCLASS64
1817 if (elf->hdr->e_machine == EM_MIPS) {
1818 unsigned int r_typ;
1819 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1820 r_sym = TO_NATIVE(r_sym);
1821 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1822 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1823 } else {
1824 r.r_info = TO_NATIVE(rela->r_info);
1825 r_sym = ELF_R_SYM(r.r_info);
1826 }
1827#else
1828 r.r_info = TO_NATIVE(rela->r_info);
1829 r_sym = ELF_R_SYM(r.r_info);
1830#endif
1831 r.r_addend = TO_NATIVE(rela->r_addend);
1832 sym = elf->symtab_start + r_sym;
1833 /* Skip special sections */
1834 if (is_shndx_special(sym->st_shndx))
1835 continue;
1836 if (is_second_extable_reloc(start, rela, fromsec))
1837 find_extable_entry_size(fromsec, &r);
1838 check_section_mismatch(modname, elf, &r, sym, fromsec);
1839 }
1840}
1841
1842static void section_rel(const char *modname, struct elf_info *elf,
1843 Elf_Shdr *sechdr)
1844{
1845 Elf_Sym *sym;
1846 Elf_Rel *rel;
1847 Elf_Rela r;
1848 unsigned int r_sym;
1849 const char *fromsec;
1850
1851 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1852 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1853
1854 fromsec = sech_name(elf, sechdr);
1855 fromsec += strlen(".rel");
1856 /* if from section (name) is know good then skip it */
1857 if (match(fromsec, section_white_list))
1858 return;
1859
1860 for (rel = start; rel < stop; rel++) {
1861 r.r_offset = TO_NATIVE(rel->r_offset);
1862#if KERNEL_ELFCLASS == ELFCLASS64
1863 if (elf->hdr->e_machine == EM_MIPS) {
1864 unsigned int r_typ;
1865 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1866 r_sym = TO_NATIVE(r_sym);
1867 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1868 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1869 } else {
1870 r.r_info = TO_NATIVE(rel->r_info);
1871 r_sym = ELF_R_SYM(r.r_info);
1872 }
1873#else
1874 r.r_info = TO_NATIVE(rel->r_info);
1875 r_sym = ELF_R_SYM(r.r_info);
1876#endif
1877 r.r_addend = 0;
1878 switch (elf->hdr->e_machine) {
1879 case EM_386:
1880 if (addend_386_rel(elf, sechdr, &r))
1881 continue;
1882 break;
1883 case EM_ARM:
1884 if (addend_arm_rel(elf, sechdr, &r))
1885 continue;
1886 break;
1887 case EM_MIPS:
1888 if (addend_mips_rel(elf, sechdr, &r))
1889 continue;
1890 break;
1891 }
1892 sym = elf->symtab_start + r_sym;
1893 /* Skip special sections */
1894 if (is_shndx_special(sym->st_shndx))
1895 continue;
1896 if (is_second_extable_reloc(start, rel, fromsec))
1897 find_extable_entry_size(fromsec, &r);
1898 check_section_mismatch(modname, elf, &r, sym, fromsec);
1899 }
1900}
1901
1902/**
1903 * A module includes a number of sections that are discarded
1904 * either when loaded or when used as built-in.
1905 * For loaded modules all functions marked __init and all data
1906 * marked __initdata will be discarded when the module has been initialized.
1907 * Likewise for modules used built-in the sections marked __exit
1908 * are discarded because __exit marked function are supposed to be called
1909 * only when a module is unloaded which never happens for built-in modules.
1910 * The check_sec_ref() function traverses all relocation records
1911 * to find all references to a section that reference a section that will
1912 * be discarded and warns about it.
1913 **/
1914static void check_sec_ref(struct module *mod, const char *modname,
1915 struct elf_info *elf)
1916{
1917 int i;
1918 Elf_Shdr *sechdrs = elf->sechdrs;
1919
1920 /* Walk through all sections */
1921 for (i = 0; i < elf->num_sections; i++) {
1922 check_section(modname, elf, &elf->sechdrs[i]);
1923 /* We want to process only relocation sections and not .init */
1924 if (sechdrs[i].sh_type == SHT_RELA)
1925 section_rela(modname, elf, &elf->sechdrs[i]);
1926 else if (sechdrs[i].sh_type == SHT_REL)
1927 section_rel(modname, elf, &elf->sechdrs[i]);
1928 }
1929}
1930
1931static char *remove_dot(char *s)
1932{
1933 size_t n = strcspn(s, ".");
1934
1935 if (n && s[n]) {
1936 size_t m = strspn(s + n + 1, "0123456789");
1937 if (m && (s[n + m] == '.' || s[n + m] == 0))
1938 s[n] = 0;
1939 }
1940 return s;
1941}
1942
1943static void read_symbols(char *modname)
1944{
1945 const char *symname;
1946 char *version;
1947 char *license;
1948 struct module *mod;
1949 struct elf_info info = { };
1950 Elf_Sym *sym;
1951
1952 if (!parse_elf(&info, modname))
1953 return;
1954
1955 mod = new_module(modname);
1956
1957 /* When there's no vmlinux, don't print warnings about
1958 * unresolved symbols (since there'll be too many ;) */
1959 if (is_vmlinux(modname)) {
1960 have_vmlinux = 1;
1961 mod->skip = 1;
1962 }
1963
1964 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1965 if (!license && !is_vmlinux(modname))
1966 warn("modpost: missing MODULE_LICENSE() in %s\n"
1967 "see include/linux/module.h for "
1968 "more information\n", modname);
1969 while (license) {
1970 if (license_is_gpl_compatible(license))
1971 mod->gpl_compatible = 1;
1972 else {
1973 mod->gpl_compatible = 0;
1974 break;
1975 }
1976 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1977 "license", license);
1978 }
1979
1980 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1981 symname = remove_dot(info.strtab + sym->st_name);
1982
1983 handle_modversions(mod, &info, sym, symname);
1984 handle_moddevtable(mod, &info, sym, symname);
1985 }
1986 if (!is_vmlinux(modname) ||
1987 (is_vmlinux(modname) && vmlinux_section_warnings))
1988 check_sec_ref(mod, modname, &info);
1989
1990 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1991 if (version)
1992 maybe_frob_rcs_version(modname, version, info.modinfo,
1993 version - (char *)info.hdr);
1994 if (version || (all_versions && !is_vmlinux(modname)))
1995 get_src_version(modname, mod->srcversion,
1996 sizeof(mod->srcversion)-1);
1997
1998 parse_elf_finish(&info);
1999
2000 /* Our trick to get versioning for module struct etc. - it's
2001 * never passed as an argument to an exported function, so
2002 * the automatic versioning doesn't pick it up, but it's really
2003 * important anyhow */
2004 if (modversions)
2005 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2006}
2007
2008static void read_symbols_from_files(const char *filename)
2009{
2010 FILE *in = stdin;
2011 char fname[PATH_MAX];
2012
2013 if (strcmp(filename, "-") != 0) {
2014 in = fopen(filename, "r");
2015 if (!in)
2016 fatal("Can't open filenames file %s: %m", filename);
2017 }
2018
2019 while (fgets(fname, PATH_MAX, in) != NULL) {
2020 if (strends(fname, "\n"))
2021 fname[strlen(fname)-1] = '\0';
2022 read_symbols(fname);
2023 }
2024
2025 if (in != stdin)
2026 fclose(in);
2027}
2028
2029#define SZ 500
2030
2031/* We first write the generated file into memory using the
2032 * following helper, then compare to the file on disk and
2033 * only update the later if anything changed */
2034
2035void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2036 const char *fmt, ...)
2037{
2038 char tmp[SZ];
2039 int len;
2040 va_list ap;
2041
2042 va_start(ap, fmt);
2043 len = vsnprintf(tmp, SZ, fmt, ap);
2044 buf_write(buf, tmp, len);
2045 va_end(ap);
2046}
2047
2048void buf_write(struct buffer *buf, const char *s, int len)
2049{
2050 if (buf->size - buf->pos < len) {
2051 buf->size += len + SZ;
2052 buf->p = realloc(buf->p, buf->size);
2053 }
2054 strncpy(buf->p + buf->pos, s, len);
2055 buf->pos += len;
2056}
2057
2058static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2059{
2060 const char *e = is_vmlinux(m) ?"":".ko";
2061
2062 switch (exp) {
2063 case export_gpl:
2064 fatal("modpost: GPL-incompatible module %s%s "
2065 "uses GPL-only symbol '%s'\n", m, e, s);
2066 break;
2067 case export_unused_gpl:
2068 fatal("modpost: GPL-incompatible module %s%s "
2069 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2070 break;
2071 case export_gpl_future:
2072 warn("modpost: GPL-incompatible module %s%s "
2073 "uses future GPL-only symbol '%s'\n", m, e, s);
2074 break;
2075 case export_plain:
2076 case export_unused:
2077 case export_unknown:
2078 /* ignore */
2079 break;
2080 }
2081}
2082
2083static void check_for_unused(enum export exp, const char *m, const char *s)
2084{
2085 const char *e = is_vmlinux(m) ?"":".ko";
2086
2087 switch (exp) {
2088 case export_unused:
2089 case export_unused_gpl:
2090 warn("modpost: module %s%s "
2091 "uses symbol '%s' marked UNUSED\n", m, e, s);
2092 break;
2093 default:
2094 /* ignore */
2095 break;
2096 }
2097}
2098
2099static void check_exports(struct module *mod)
2100{
2101 struct symbol *s, *exp;
2102
2103 for (s = mod->unres; s; s = s->next) {
2104 const char *basename;
2105 exp = find_symbol(s->name);
2106 if (!exp || exp->module == mod)
2107 continue;
2108 basename = strrchr(mod->name, '/');
2109 if (basename)
2110 basename++;
2111 else
2112 basename = mod->name;
2113 if (!mod->gpl_compatible)
2114 check_for_gpl_usage(exp->export, basename, exp->name);
2115 check_for_unused(exp->export, basename, exp->name);
2116 }
2117}
2118
2119static int check_modname_len(struct module *mod)
2120{
2121 const char *mod_name;
2122
2123 mod_name = strrchr(mod->name, '/');
2124 if (mod_name == NULL)
2125 mod_name = mod->name;
2126 else
2127 mod_name++;
2128 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2129 merror("module name is too long [%s.ko]\n", mod->name);
2130 return 1;
2131 }
2132
2133 return 0;
2134}
2135
2136/**
2137 * Header for the generated file
2138 **/
2139static void add_header(struct buffer *b, struct module *mod)
2140{
2141 buf_printf(b, "#include <linux/module.h>\n");
2142 buf_printf(b, "#include <linux/vermagic.h>\n");
2143 buf_printf(b, "#include <linux/compiler.h>\n");
2144 buf_printf(b, "\n");
2145 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2146 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2147 buf_printf(b, "\n");
2148 buf_printf(b, "__visible struct module __this_module\n");
2149 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2150 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2151 if (mod->has_init)
2152 buf_printf(b, "\t.init = init_module,\n");
2153 if (mod->has_cleanup)
2154 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2155 "\t.exit = cleanup_module,\n"
2156 "#endif\n");
2157 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2158 buf_printf(b, "};\n");
2159}
2160
2161static void add_intree_flag(struct buffer *b, int is_intree)
2162{
2163 if (is_intree)
2164 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2165}
2166
2167/* Cannot check for assembler */
2168static void add_retpoline(struct buffer *b)
2169{
2170 buf_printf(b, "\n#ifdef RETPOLINE\n");
2171 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2172 buf_printf(b, "#endif\n");
2173}
2174
2175static void add_staging_flag(struct buffer *b, const char *name)
2176{
2177 static const char *staging_dir = "drivers/staging";
2178
2179 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2180 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2181}
2182
2183/**
2184 * Record CRCs for unresolved symbols
2185 **/
2186static int add_versions(struct buffer *b, struct module *mod)
2187{
2188 struct symbol *s, *exp;
2189 int err = 0;
2190
2191 for (s = mod->unres; s; s = s->next) {
2192 exp = find_symbol(s->name);
2193 if (!exp || exp->module == mod) {
2194 if (have_vmlinux && !s->weak) {
2195 if (warn_unresolved) {
2196 warn("\"%s\" [%s.ko] undefined!\n",
2197 s->name, mod->name);
2198 } else {
2199 merror("\"%s\" [%s.ko] undefined!\n",
2200 s->name, mod->name);
2201 err = 1;
2202 }
2203 }
2204 continue;
2205 }
2206 s->module = exp->module;
2207 s->crc_valid = exp->crc_valid;
2208 s->crc = exp->crc;
2209 }
2210
2211 if (!modversions)
2212 return err;
2213
2214 buf_printf(b, "\n");
2215 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2216 buf_printf(b, "__used\n");
2217 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2218
2219 for (s = mod->unres; s; s = s->next) {
2220 if (!s->module)
2221 continue;
2222 if (!s->crc_valid) {
2223 warn("\"%s\" [%s.ko] has no CRC!\n",
2224 s->name, mod->name);
2225 continue;
2226 }
2227 if (strlen(s->name) >= MODULE_NAME_LEN) {
2228 merror("too long symbol \"%s\" [%s.ko]\n",
2229 s->name, mod->name);
2230 err = 1;
2231 break;
2232 }
2233 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2234 s->crc, s->name);
2235 }
2236
2237 buf_printf(b, "};\n");
2238
2239 return err;
2240}
2241
2242static void add_depends(struct buffer *b, struct module *mod,
2243 struct module *modules)
2244{
2245 struct symbol *s;
2246 struct module *m;
2247 int first = 1;
2248
2249 for (m = modules; m; m = m->next)
2250 m->seen = is_vmlinux(m->name);
2251
2252 buf_printf(b, "\n");
2253 buf_printf(b, "static const char __module_depends[]\n");
2254 buf_printf(b, "__used\n");
2255 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2256 buf_printf(b, "\"depends=");
2257 for (s = mod->unres; s; s = s->next) {
2258 const char *p;
2259 if (!s->module)
2260 continue;
2261
2262 if (s->module->seen)
2263 continue;
2264
2265 s->module->seen = 1;
2266 p = strrchr(s->module->name, '/');
2267 if (p)
2268 p++;
2269 else
2270 p = s->module->name;
2271 buf_printf(b, "%s%s", first ? "" : ",", p);
2272 first = 0;
2273 }
2274 buf_printf(b, "\";\n");
2275}
2276
2277static void add_srcversion(struct buffer *b, struct module *mod)
2278{
2279 if (mod->srcversion[0]) {
2280 buf_printf(b, "\n");
2281 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2282 mod->srcversion);
2283 }
2284}
2285
2286static void write_if_changed(struct buffer *b, const char *fname)
2287{
2288 char *tmp;
2289 FILE *file;
2290 struct stat st;
2291
2292 file = fopen(fname, "r");
2293 if (!file)
2294 goto write;
2295
2296 if (fstat(fileno(file), &st) < 0)
2297 goto close_write;
2298
2299 if (st.st_size != b->pos)
2300 goto close_write;
2301
2302 tmp = NOFAIL(malloc(b->pos));
2303 if (fread(tmp, 1, b->pos, file) != b->pos)
2304 goto free_write;
2305
2306 if (memcmp(tmp, b->p, b->pos) != 0)
2307 goto free_write;
2308
2309 free(tmp);
2310 fclose(file);
2311 return;
2312
2313 free_write:
2314 free(tmp);
2315 close_write:
2316 fclose(file);
2317 write:
2318 file = fopen(fname, "w");
2319 if (!file) {
2320 perror(fname);
2321 exit(1);
2322 }
2323 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2324 perror(fname);
2325 exit(1);
2326 }
2327 fclose(file);
2328}
2329
2330/* parse Module.symvers file. line format:
2331 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2332 **/
2333static void read_dump(const char *fname, unsigned int kernel)
2334{
2335 unsigned long size, pos = 0;
2336 void *file = grab_file(fname, &size);
2337 char *line;
2338
2339 if (!file)
2340 /* No symbol versions, silently ignore */
2341 return;
2342
2343 while ((line = get_next_line(&pos, file, size))) {
2344 char *symname, *modname, *d, *export, *end;
2345 unsigned int crc;
2346 struct module *mod;
2347 struct symbol *s;
2348
2349 if (!(symname = strchr(line, '\t')))
2350 goto fail;
2351 *symname++ = '\0';
2352 if (!(modname = strchr(symname, '\t')))
2353 goto fail;
2354 *modname++ = '\0';
2355 if ((export = strchr(modname, '\t')) != NULL)
2356 *export++ = '\0';
2357 if (export && ((end = strchr(export, '\t')) != NULL))
2358 *end = '\0';
2359 crc = strtoul(line, &d, 16);
2360 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2361 goto fail;
2362 mod = find_module(modname);
2363 if (!mod) {
2364 if (is_vmlinux(modname))
2365 have_vmlinux = 1;
2366 mod = new_module(modname);
2367 mod->skip = 1;
2368 }
2369 s = sym_add_exported(symname, mod, export_no(export));
2370 s->kernel = kernel;
2371 s->preloaded = 1;
2372 sym_update_crc(symname, mod, crc, export_no(export));
2373 }
2374 release_file(file, size);
2375 return;
2376fail:
2377 release_file(file, size);
2378 fatal("parse error in symbol dump file\n");
2379}
2380
2381/* For normal builds always dump all symbols.
2382 * For external modules only dump symbols
2383 * that are not read from kernel Module.symvers.
2384 **/
2385static int dump_sym(struct symbol *sym)
2386{
2387 if (!external_module)
2388 return 1;
2389 if (sym->vmlinux || sym->kernel)
2390 return 0;
2391 return 1;
2392}
2393
2394static void write_dump(const char *fname)
2395{
2396 struct buffer buf = { };
2397 struct symbol *symbol;
2398 int n;
2399
2400 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2401 symbol = symbolhash[n];
2402 while (symbol) {
2403 if (dump_sym(symbol))
2404 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2405 symbol->crc, symbol->name,
2406 symbol->module->name,
2407 export_str(symbol->export));
2408 symbol = symbol->next;
2409 }
2410 }
2411 write_if_changed(&buf, fname);
2412 free(buf.p);
2413}
2414
2415struct ext_sym_list {
2416 struct ext_sym_list *next;
2417 const char *file;
2418};
2419
2420int main(int argc, char **argv)
2421{
2422 struct module *mod;
2423 struct buffer buf = { };
2424 char *kernel_read = NULL, *module_read = NULL;
2425 char *dump_write = NULL, *files_source = NULL;
2426 int opt;
2427 int err;
2428 struct ext_sym_list *extsym_iter;
2429 struct ext_sym_list *extsym_start = NULL;
2430
2431 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2432 switch (opt) {
2433 case 'i':
2434 kernel_read = optarg;
2435 break;
2436 case 'I':
2437 module_read = optarg;
2438 external_module = 1;
2439 break;
2440 case 'e':
2441 external_module = 1;
2442 extsym_iter =
2443 NOFAIL(malloc(sizeof(*extsym_iter)));
2444 extsym_iter->next = extsym_start;
2445 extsym_iter->file = optarg;
2446 extsym_start = extsym_iter;
2447 break;
2448 case 'm':
2449 modversions = 1;
2450 break;
2451 case 'n':
2452 ignore_missing_files = 1;
2453 break;
2454 case 'o':
2455 dump_write = optarg;
2456 break;
2457 case 'a':
2458 all_versions = 1;
2459 break;
2460 case 's':
2461 vmlinux_section_warnings = 0;
2462 break;
2463 case 'S':
2464 sec_mismatch_verbose = 0;
2465 break;
2466 case 'T':
2467 files_source = optarg;
2468 break;
2469 case 'w':
2470 warn_unresolved = 1;
2471 break;
2472 case 'E':
2473 sec_mismatch_fatal = 1;
2474 break;
2475 default:
2476 exit(1);
2477 }
2478 }
2479
2480 if (kernel_read)
2481 read_dump(kernel_read, 1);
2482 if (module_read)
2483 read_dump(module_read, 0);
2484 while (extsym_start) {
2485 read_dump(extsym_start->file, 0);
2486 extsym_iter = extsym_start->next;
2487 free(extsym_start);
2488 extsym_start = extsym_iter;
2489 }
2490
2491 while (optind < argc)
2492 read_symbols(argv[optind++]);
2493
2494 if (files_source)
2495 read_symbols_from_files(files_source);
2496
2497 for (mod = modules; mod; mod = mod->next) {
2498 if (mod->skip)
2499 continue;
2500 check_exports(mod);
2501 }
2502
2503 err = 0;
2504
2505 for (mod = modules; mod; mod = mod->next) {
2506 char fname[PATH_MAX];
2507
2508 if (mod->skip)
2509 continue;
2510
2511 buf.pos = 0;
2512
2513 err |= check_modname_len(mod);
2514 add_header(&buf, mod);
2515 add_intree_flag(&buf, !external_module);
2516 add_retpoline(&buf);
2517 add_staging_flag(&buf, mod->name);
2518 err |= add_versions(&buf, mod);
2519 add_depends(&buf, mod, modules);
2520 add_moddevtable(&buf, mod);
2521 add_srcversion(&buf, mod);
2522
2523 sprintf(fname, "%s.mod.c", mod->name);
2524 write_if_changed(&buf, fname);
2525 }
2526 if (dump_write)
2527 write_dump(dump_write);
2528 if (sec_mismatch_count) {
2529 if (!sec_mismatch_verbose) {
2530 warn("modpost: Found %d section mismatch(es).\n"
2531 "To see full details build your kernel with:\n"
2532 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2533 sec_mismatch_count);
2534 }
2535 if (sec_mismatch_fatal) {
2536 fatal("modpost: Section mismatches detected.\n"
2537 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2538 }
2539 }
2540 free(buf.p);
2541
2542 return err;
2543}
1/* Postprocess module symbol versions
2 *
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006-2008 Sam Ravnborg
6 * Based in part on module-init-tools/depmod.c,file2alias
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * Usage: modpost vmlinux module1.o module2.o ...
12 */
13
14#define _GNU_SOURCE
15#include <elf.h>
16#include <fnmatch.h>
17#include <stdio.h>
18#include <ctype.h>
19#include <string.h>
20#include <limits.h>
21#include <stdbool.h>
22#include <errno.h>
23
24#include <hash.h>
25#include <hashtable.h>
26#include <list.h>
27#include <xalloc.h>
28#include "modpost.h"
29#include "../../include/linux/license.h"
30
31static bool module_enabled;
32/* Are we using CONFIG_MODVERSIONS? */
33static bool modversions;
34/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
35static bool all_versions;
36/* If we are modposting external module set to 1 */
37static bool external_module;
38/* Only warn about unresolved symbols */
39static bool warn_unresolved;
40
41static int sec_mismatch_count;
42static bool sec_mismatch_warn_only = true;
43/* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
44static bool trim_unused_exports;
45
46/* ignore missing files */
47static bool ignore_missing_files;
48/* If set to 1, only warn (instead of error) about missing ns imports */
49static bool allow_missing_ns_imports;
50
51static bool error_occurred;
52
53static bool extra_warn;
54
55bool target_is_big_endian;
56bool host_is_big_endian;
57
58/*
59 * Cut off the warnings when there are too many. This typically occurs when
60 * vmlinux is missing. ('make modules' without building vmlinux.)
61 */
62#define MAX_UNRESOLVED_REPORTS 10
63static unsigned int nr_unresolved;
64
65/* In kernel, this size is defined in linux/module.h;
66 * here we use Elf_Addr instead of long for covering cross-compile
67 */
68
69#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
70
71void modpost_log(bool is_error, const char *fmt, ...)
72{
73 va_list arglist;
74
75 if (is_error) {
76 fprintf(stderr, "ERROR: ");
77 error_occurred = true;
78 } else {
79 fprintf(stderr, "WARNING: ");
80 }
81
82 fprintf(stderr, "modpost: ");
83
84 va_start(arglist, fmt);
85 vfprintf(stderr, fmt, arglist);
86 va_end(arglist);
87}
88
89static inline bool strends(const char *str, const char *postfix)
90{
91 if (strlen(str) < strlen(postfix))
92 return false;
93
94 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
95}
96
97char *read_text_file(const char *filename)
98{
99 struct stat st;
100 size_t nbytes;
101 int fd;
102 char *buf;
103
104 fd = open(filename, O_RDONLY);
105 if (fd < 0) {
106 perror(filename);
107 exit(1);
108 }
109
110 if (fstat(fd, &st) < 0) {
111 perror(filename);
112 exit(1);
113 }
114
115 buf = xmalloc(st.st_size + 1);
116
117 nbytes = st.st_size;
118
119 while (nbytes) {
120 ssize_t bytes_read;
121
122 bytes_read = read(fd, buf, nbytes);
123 if (bytes_read < 0) {
124 perror(filename);
125 exit(1);
126 }
127
128 nbytes -= bytes_read;
129 }
130 buf[st.st_size] = '\0';
131
132 close(fd);
133
134 return buf;
135}
136
137char *get_line(char **stringp)
138{
139 char *orig = *stringp, *next;
140
141 /* do not return the unwanted extra line at EOF */
142 if (!orig || *orig == '\0')
143 return NULL;
144
145 /* don't use strsep here, it is not available everywhere */
146 next = strchr(orig, '\n');
147 if (next)
148 *next++ = '\0';
149
150 *stringp = next;
151
152 return orig;
153}
154
155/* A list of all modules we processed */
156LIST_HEAD(modules);
157
158static struct module *find_module(const char *filename, const char *modname)
159{
160 struct module *mod;
161
162 list_for_each_entry(mod, &modules, list) {
163 if (!strcmp(mod->dump_file, filename) &&
164 !strcmp(mod->name, modname))
165 return mod;
166 }
167 return NULL;
168}
169
170static struct module *new_module(const char *name, size_t namelen)
171{
172 struct module *mod;
173
174 mod = xmalloc(sizeof(*mod) + namelen + 1);
175 memset(mod, 0, sizeof(*mod));
176
177 INIT_LIST_HEAD(&mod->exported_symbols);
178 INIT_LIST_HEAD(&mod->unresolved_symbols);
179 INIT_LIST_HEAD(&mod->missing_namespaces);
180 INIT_LIST_HEAD(&mod->imported_namespaces);
181 INIT_LIST_HEAD(&mod->aliases);
182
183 memcpy(mod->name, name, namelen);
184 mod->name[namelen] = '\0';
185 mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
186
187 /*
188 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
189 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
190 * modpost will exit wiht error anyway.
191 */
192 mod->is_gpl_compatible = true;
193
194 list_add_tail(&mod->list, &modules);
195
196 return mod;
197}
198
199struct symbol {
200 struct hlist_node hnode;/* link to hash table */
201 struct list_head list; /* link to module::exported_symbols or module::unresolved_symbols */
202 struct module *module;
203 char *namespace;
204 unsigned int crc;
205 bool crc_valid;
206 bool weak;
207 bool is_func;
208 bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */
209 bool used; /* there exists a user of this symbol */
210 char name[];
211};
212
213static HASHTABLE_DEFINE(symbol_hashtable, 1U << 10);
214
215/**
216 * Allocate a new symbols for use in the hash of exported symbols or
217 * the list of unresolved symbols per module
218 **/
219static struct symbol *alloc_symbol(const char *name)
220{
221 struct symbol *s = xmalloc(sizeof(*s) + strlen(name) + 1);
222
223 memset(s, 0, sizeof(*s));
224 strcpy(s->name, name);
225
226 return s;
227}
228
229/* For the hash of exported symbols */
230static void hash_add_symbol(struct symbol *sym)
231{
232 hash_add(symbol_hashtable, &sym->hnode, hash_str(sym->name));
233}
234
235static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
236{
237 struct symbol *sym;
238
239 sym = alloc_symbol(name);
240 sym->weak = weak;
241
242 list_add_tail(&sym->list, &mod->unresolved_symbols);
243}
244
245static struct symbol *sym_find_with_module(const char *name, struct module *mod)
246{
247 struct symbol *s;
248
249 /* For our purposes, .foo matches foo. PPC64 needs this. */
250 if (name[0] == '.')
251 name++;
252
253 hash_for_each_possible(symbol_hashtable, s, hnode, hash_str(name)) {
254 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
255 return s;
256 }
257 return NULL;
258}
259
260static struct symbol *find_symbol(const char *name)
261{
262 return sym_find_with_module(name, NULL);
263}
264
265struct namespace_list {
266 struct list_head list;
267 char namespace[];
268};
269
270static bool contains_namespace(struct list_head *head, const char *namespace)
271{
272 struct namespace_list *list;
273
274 /*
275 * The default namespace is null string "", which is always implicitly
276 * contained.
277 */
278 if (!namespace[0])
279 return true;
280
281 list_for_each_entry(list, head, list) {
282 if (!strcmp(list->namespace, namespace))
283 return true;
284 }
285
286 return false;
287}
288
289static void add_namespace(struct list_head *head, const char *namespace)
290{
291 struct namespace_list *ns_entry;
292
293 if (!contains_namespace(head, namespace)) {
294 ns_entry = xmalloc(sizeof(*ns_entry) + strlen(namespace) + 1);
295 strcpy(ns_entry->namespace, namespace);
296 list_add_tail(&ns_entry->list, head);
297 }
298}
299
300static void *sym_get_data_by_offset(const struct elf_info *info,
301 unsigned int secindex, unsigned long offset)
302{
303 Elf_Shdr *sechdr = &info->sechdrs[secindex];
304
305 return (void *)info->hdr + sechdr->sh_offset + offset;
306}
307
308void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
309{
310 return sym_get_data_by_offset(info, get_secindex(info, sym),
311 sym->st_value);
312}
313
314static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
315{
316 return sym_get_data_by_offset(info, info->secindex_strings,
317 sechdr->sh_name);
318}
319
320static const char *sec_name(const struct elf_info *info, unsigned int secindex)
321{
322 /*
323 * If sym->st_shndx is a special section index, there is no
324 * corresponding section header.
325 * Return "" if the index is out of range of info->sechdrs[] array.
326 */
327 if (secindex >= info->num_sections)
328 return "";
329
330 return sech_name(info, &info->sechdrs[secindex]);
331}
332
333static struct symbol *sym_add_exported(const char *name, struct module *mod,
334 bool gpl_only, const char *namespace)
335{
336 struct symbol *s = find_symbol(name);
337
338 if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
339 error("%s: '%s' exported twice. Previous export was in %s%s\n",
340 mod->name, name, s->module->name,
341 s->module->is_vmlinux ? "" : ".ko");
342 }
343
344 s = alloc_symbol(name);
345 s->module = mod;
346 s->is_gpl_only = gpl_only;
347 s->namespace = xstrdup(namespace);
348 list_add_tail(&s->list, &mod->exported_symbols);
349 hash_add_symbol(s);
350
351 return s;
352}
353
354static void sym_set_crc(struct symbol *sym, unsigned int crc)
355{
356 sym->crc = crc;
357 sym->crc_valid = true;
358}
359
360static void *grab_file(const char *filename, size_t *size)
361{
362 struct stat st;
363 void *map = MAP_FAILED;
364 int fd;
365
366 fd = open(filename, O_RDONLY);
367 if (fd < 0)
368 return NULL;
369 if (fstat(fd, &st))
370 goto failed;
371
372 *size = st.st_size;
373 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
374
375failed:
376 close(fd);
377 if (map == MAP_FAILED)
378 return NULL;
379 return map;
380}
381
382static void release_file(void *file, size_t size)
383{
384 munmap(file, size);
385}
386
387static int parse_elf(struct elf_info *info, const char *filename)
388{
389 unsigned int i;
390 Elf_Ehdr *hdr;
391 Elf_Shdr *sechdrs;
392 Elf_Sym *sym;
393 const char *secstrings;
394 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
395
396 hdr = grab_file(filename, &info->size);
397 if (!hdr) {
398 if (ignore_missing_files) {
399 fprintf(stderr, "%s: %s (ignored)\n", filename,
400 strerror(errno));
401 return 0;
402 }
403 perror(filename);
404 exit(1);
405 }
406 info->hdr = hdr;
407 if (info->size < sizeof(*hdr)) {
408 /* file too small, assume this is an empty .o file */
409 return 0;
410 }
411 /* Is this a valid ELF file? */
412 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
413 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
414 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
415 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
416 /* Not an ELF file - silently ignore it */
417 return 0;
418 }
419
420 switch (hdr->e_ident[EI_DATA]) {
421 case ELFDATA2LSB:
422 target_is_big_endian = false;
423 break;
424 case ELFDATA2MSB:
425 target_is_big_endian = true;
426 break;
427 default:
428 fatal("target endian is unknown\n");
429 }
430
431 /* Fix endianness in ELF header */
432 hdr->e_type = TO_NATIVE(hdr->e_type);
433 hdr->e_machine = TO_NATIVE(hdr->e_machine);
434 hdr->e_version = TO_NATIVE(hdr->e_version);
435 hdr->e_entry = TO_NATIVE(hdr->e_entry);
436 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
437 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
438 hdr->e_flags = TO_NATIVE(hdr->e_flags);
439 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
440 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
441 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
442 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
443 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
444 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
445 sechdrs = (void *)hdr + hdr->e_shoff;
446 info->sechdrs = sechdrs;
447
448 /* modpost only works for relocatable objects */
449 if (hdr->e_type != ET_REL)
450 fatal("%s: not relocatable object.", filename);
451
452 /* Check if file offset is correct */
453 if (hdr->e_shoff > info->size)
454 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
455 (unsigned long)hdr->e_shoff, filename, info->size);
456
457 if (hdr->e_shnum == SHN_UNDEF) {
458 /*
459 * There are more than 64k sections,
460 * read count from .sh_size.
461 */
462 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
463 }
464 else {
465 info->num_sections = hdr->e_shnum;
466 }
467 if (hdr->e_shstrndx == SHN_XINDEX) {
468 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
469 }
470 else {
471 info->secindex_strings = hdr->e_shstrndx;
472 }
473
474 /* Fix endianness in section headers */
475 for (i = 0; i < info->num_sections; i++) {
476 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
477 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
478 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
479 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
480 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
481 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
482 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
483 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
484 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
485 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
486 }
487 /* Find symbol table. */
488 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
489 for (i = 1; i < info->num_sections; i++) {
490 const char *secname;
491 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
492
493 if (!nobits && sechdrs[i].sh_offset > info->size)
494 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
495 filename, (unsigned long)sechdrs[i].sh_offset,
496 sizeof(*hdr));
497
498 secname = secstrings + sechdrs[i].sh_name;
499 if (strcmp(secname, ".modinfo") == 0) {
500 if (nobits)
501 fatal("%s has NOBITS .modinfo\n", filename);
502 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
503 info->modinfo_len = sechdrs[i].sh_size;
504 } else if (!strcmp(secname, ".export_symbol")) {
505 info->export_symbol_secndx = i;
506 }
507
508 if (sechdrs[i].sh_type == SHT_SYMTAB) {
509 unsigned int sh_link_idx;
510 symtab_idx = i;
511 info->symtab_start = (void *)hdr +
512 sechdrs[i].sh_offset;
513 info->symtab_stop = (void *)hdr +
514 sechdrs[i].sh_offset + sechdrs[i].sh_size;
515 sh_link_idx = sechdrs[i].sh_link;
516 info->strtab = (void *)hdr +
517 sechdrs[sh_link_idx].sh_offset;
518 }
519
520 /* 32bit section no. table? ("more than 64k sections") */
521 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
522 symtab_shndx_idx = i;
523 info->symtab_shndx_start = (void *)hdr +
524 sechdrs[i].sh_offset;
525 info->symtab_shndx_stop = (void *)hdr +
526 sechdrs[i].sh_offset + sechdrs[i].sh_size;
527 }
528 }
529 if (!info->symtab_start)
530 fatal("%s has no symtab?\n", filename);
531
532 /* Fix endianness in symbols */
533 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
534 sym->st_shndx = TO_NATIVE(sym->st_shndx);
535 sym->st_name = TO_NATIVE(sym->st_name);
536 sym->st_value = TO_NATIVE(sym->st_value);
537 sym->st_size = TO_NATIVE(sym->st_size);
538 }
539
540 if (symtab_shndx_idx != ~0U) {
541 Elf32_Word *p;
542 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
543 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
544 filename, sechdrs[symtab_shndx_idx].sh_link,
545 symtab_idx);
546 /* Fix endianness */
547 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
548 p++)
549 *p = TO_NATIVE(*p);
550 }
551
552 symsearch_init(info);
553
554 return 1;
555}
556
557static void parse_elf_finish(struct elf_info *info)
558{
559 symsearch_finish(info);
560 release_file(info->hdr, info->size);
561}
562
563static int ignore_undef_symbol(struct elf_info *info, const char *symname)
564{
565 /* ignore __this_module, it will be resolved shortly */
566 if (strcmp(symname, "__this_module") == 0)
567 return 1;
568 /* ignore global offset table */
569 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
570 return 1;
571 if (info->hdr->e_machine == EM_PPC)
572 /* Special register function linked on all modules during final link of .ko */
573 if (strstarts(symname, "_restgpr_") ||
574 strstarts(symname, "_savegpr_") ||
575 strstarts(symname, "_rest32gpr_") ||
576 strstarts(symname, "_save32gpr_") ||
577 strstarts(symname, "_restvr_") ||
578 strstarts(symname, "_savevr_"))
579 return 1;
580 if (info->hdr->e_machine == EM_PPC64)
581 /* Special register function linked on all modules during final link of .ko */
582 if (strstarts(symname, "_restgpr0_") ||
583 strstarts(symname, "_savegpr0_") ||
584 strstarts(symname, "_restvr_") ||
585 strstarts(symname, "_savevr_") ||
586 strcmp(symname, ".TOC.") == 0)
587 return 1;
588 /* Do not ignore this symbol */
589 return 0;
590}
591
592static void handle_symbol(struct module *mod, struct elf_info *info,
593 const Elf_Sym *sym, const char *symname)
594{
595 switch (sym->st_shndx) {
596 case SHN_COMMON:
597 if (strstarts(symname, "__gnu_lto_")) {
598 /* Should warn here, but modpost runs before the linker */
599 } else
600 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
601 break;
602 case SHN_UNDEF:
603 /* undefined symbol */
604 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
605 ELF_ST_BIND(sym->st_info) != STB_WEAK)
606 break;
607 if (ignore_undef_symbol(info, symname))
608 break;
609 if (info->hdr->e_machine == EM_SPARC ||
610 info->hdr->e_machine == EM_SPARCV9) {
611 /* Ignore register directives. */
612 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
613 break;
614 if (symname[0] == '.') {
615 char *munged = xstrdup(symname);
616 munged[0] = '_';
617 munged[1] = toupper(munged[1]);
618 symname = munged;
619 }
620 }
621
622 sym_add_unresolved(symname, mod,
623 ELF_ST_BIND(sym->st_info) == STB_WEAK);
624 break;
625 default:
626 if (strcmp(symname, "init_module") == 0)
627 mod->has_init = true;
628 if (strcmp(symname, "cleanup_module") == 0)
629 mod->has_cleanup = true;
630 break;
631 }
632}
633
634/**
635 * Parse tag=value strings from .modinfo section
636 **/
637static char *next_string(char *string, unsigned long *secsize)
638{
639 /* Skip non-zero chars */
640 while (string[0]) {
641 string++;
642 if ((*secsize)-- <= 1)
643 return NULL;
644 }
645
646 /* Skip any zero padding. */
647 while (!string[0]) {
648 string++;
649 if ((*secsize)-- <= 1)
650 return NULL;
651 }
652 return string;
653}
654
655static char *get_next_modinfo(struct elf_info *info, const char *tag,
656 char *prev)
657{
658 char *p;
659 unsigned int taglen = strlen(tag);
660 char *modinfo = info->modinfo;
661 unsigned long size = info->modinfo_len;
662
663 if (prev) {
664 size -= prev - modinfo;
665 modinfo = next_string(prev, &size);
666 }
667
668 for (p = modinfo; p; p = next_string(p, &size)) {
669 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
670 return p + taglen + 1;
671 }
672 return NULL;
673}
674
675static char *get_modinfo(struct elf_info *info, const char *tag)
676
677{
678 return get_next_modinfo(info, tag, NULL);
679}
680
681static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
682{
683 return sym ? elf->strtab + sym->st_name : "";
684}
685
686/*
687 * Check whether the 'string' argument matches one of the 'patterns',
688 * an array of shell wildcard patterns (glob).
689 *
690 * Return true is there is a match.
691 */
692static bool match(const char *string, const char *const patterns[])
693{
694 const char *pattern;
695
696 while ((pattern = *patterns++)) {
697 if (!fnmatch(pattern, string, 0))
698 return true;
699 }
700
701 return false;
702}
703
704/* useful to pass patterns to match() directly */
705#define PATTERNS(...) \
706 ({ \
707 static const char *const patterns[] = {__VA_ARGS__, NULL}; \
708 patterns; \
709 })
710
711/* sections that we do not want to do full section mismatch check on */
712static const char *const section_white_list[] =
713{
714 ".comment*",
715 ".debug*",
716 ".zdebug*", /* Compressed debug sections. */
717 ".GCC.command.line", /* record-gcc-switches */
718 ".mdebug*", /* alpha, score, mips etc. */
719 ".pdr", /* alpha, score, mips etc. */
720 ".stab*",
721 ".note*",
722 ".got*",
723 ".toc*",
724 ".xt.prop", /* xtensa */
725 ".xt.lit", /* xtensa */
726 ".arcextmap*", /* arc */
727 ".gnu.linkonce.arcext*", /* arc : modules */
728 ".cmem*", /* EZchip */
729 ".fmt_slot*", /* EZchip */
730 ".gnu.lto*",
731 ".discard.*",
732 ".llvm.call-graph-profile", /* call graph */
733 NULL
734};
735
736/*
737 * This is used to find sections missing the SHF_ALLOC flag.
738 * The cause of this is often a section specified in assembler
739 * without "ax" / "aw".
740 */
741static void check_section(const char *modname, struct elf_info *elf,
742 Elf_Shdr *sechdr)
743{
744 const char *sec = sech_name(elf, sechdr);
745
746 if (sechdr->sh_type == SHT_PROGBITS &&
747 !(sechdr->sh_flags & SHF_ALLOC) &&
748 !match(sec, section_white_list)) {
749 warn("%s (%s): unexpected non-allocatable section.\n"
750 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
751 "Note that for example <linux/init.h> contains\n"
752 "section definitions for use in .S files.\n\n",
753 modname, sec);
754 }
755}
756
757
758
759#define ALL_INIT_DATA_SECTIONS \
760 ".init.setup", ".init.rodata", ".init.data"
761
762#define ALL_PCI_INIT_SECTIONS \
763 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
764 ".pci_fixup_enable", ".pci_fixup_resume", \
765 ".pci_fixup_resume_early", ".pci_fixup_suspend"
766
767#define ALL_INIT_SECTIONS ".init.*"
768#define ALL_EXIT_SECTIONS ".exit.*"
769
770#define DATA_SECTIONS ".data", ".data.rel"
771#define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
772 ".kprobes.text", ".cpuidle.text", ".noinstr.text", \
773 ".ltext", ".ltext.*"
774#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
775 ".fixup", ".entry.text", ".exception.text", \
776 ".coldtext", ".softirqentry.text", ".irqentry.text"
777
778#define ALL_TEXT_SECTIONS ".init.text", ".exit.text", \
779 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
780
781enum mismatch {
782 TEXTDATA_TO_ANY_INIT_EXIT,
783 XXXINIT_TO_SOME_INIT,
784 ANY_INIT_TO_ANY_EXIT,
785 ANY_EXIT_TO_ANY_INIT,
786 EXTABLE_TO_NON_TEXT,
787};
788
789/**
790 * Describe how to match sections on different criteria:
791 *
792 * @fromsec: Array of sections to be matched.
793 *
794 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
795 * this array is forbidden (black-list). Can be empty.
796 *
797 * @good_tosec: Relocations applied to a section in @fromsec must be
798 * targeting sections in this array (white-list). Can be empty.
799 *
800 * @mismatch: Type of mismatch.
801 */
802struct sectioncheck {
803 const char *fromsec[20];
804 const char *bad_tosec[20];
805 const char *good_tosec[20];
806 enum mismatch mismatch;
807};
808
809static const struct sectioncheck sectioncheck[] = {
810/* Do not reference init/exit code/data from
811 * normal code and data
812 */
813{
814 .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
815 .bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
816 .mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
817},
818/* Do not use exit code/data from init code */
819{
820 .fromsec = { ALL_INIT_SECTIONS, NULL },
821 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
822 .mismatch = ANY_INIT_TO_ANY_EXIT,
823},
824/* Do not use init code/data from exit code */
825{
826 .fromsec = { ALL_EXIT_SECTIONS, NULL },
827 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
828 .mismatch = ANY_EXIT_TO_ANY_INIT,
829},
830{
831 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
832 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
833 .mismatch = ANY_INIT_TO_ANY_EXIT,
834},
835{
836 .fromsec = { "__ex_table", NULL },
837 /* If you're adding any new black-listed sections in here, consider
838 * adding a special 'printer' for them in scripts/check_extable.
839 */
840 .bad_tosec = { ".altinstr_replacement", NULL },
841 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
842 .mismatch = EXTABLE_TO_NON_TEXT,
843}
844};
845
846static const struct sectioncheck *section_mismatch(
847 const char *fromsec, const char *tosec)
848{
849 int i;
850
851 /*
852 * The target section could be the SHT_NUL section when we're
853 * handling relocations to un-resolved symbols, trying to match it
854 * doesn't make much sense and causes build failures on parisc
855 * architectures.
856 */
857 if (*tosec == '\0')
858 return NULL;
859
860 for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
861 const struct sectioncheck *check = §ioncheck[i];
862
863 if (match(fromsec, check->fromsec)) {
864 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
865 return check;
866 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
867 return check;
868 }
869 }
870 return NULL;
871}
872
873/**
874 * Whitelist to allow certain references to pass with no warning.
875 *
876 * Pattern 1:
877 * If a module parameter is declared __initdata and permissions=0
878 * then this is legal despite the warning generated.
879 * We cannot see value of permissions here, so just ignore
880 * this pattern.
881 * The pattern is identified by:
882 * tosec = .init.data
883 * fromsec = .data*
884 * atsym =__param*
885 *
886 * Pattern 1a:
887 * module_param_call() ops can refer to __init set function if permissions=0
888 * The pattern is identified by:
889 * tosec = .init.text
890 * fromsec = .data*
891 * atsym = __param_ops_*
892 *
893 * Pattern 3:
894 * Whitelist all references from .head.text to any init section
895 *
896 * Pattern 4:
897 * Some symbols belong to init section but still it is ok to reference
898 * these from non-init sections as these symbols don't have any memory
899 * allocated for them and symbol address and value are same. So even
900 * if init section is freed, its ok to reference those symbols.
901 * For ex. symbols marking the init section boundaries.
902 * This pattern is identified by
903 * refsymname = __init_begin, _sinittext, _einittext
904 *
905 * Pattern 5:
906 * GCC may optimize static inlines when fed constant arg(s) resulting
907 * in functions like cpumask_empty() -- generating an associated symbol
908 * cpumask_empty.constprop.3 that appears in the audit. If the const that
909 * is passed in comes from __init, like say nmi_ipi_mask, we get a
910 * meaningless section warning. May need to add isra symbols too...
911 * This pattern is identified by
912 * tosec = init section
913 * fromsec = text section
914 * refsymname = *.constprop.*
915 *
916 **/
917static int secref_whitelist(const char *fromsec, const char *fromsym,
918 const char *tosec, const char *tosym)
919{
920 /* Check for pattern 1 */
921 if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
922 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
923 strstarts(fromsym, "__param"))
924 return 0;
925
926 /* Check for pattern 1a */
927 if (strcmp(tosec, ".init.text") == 0 &&
928 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
929 strstarts(fromsym, "__param_ops_"))
930 return 0;
931
932 /* symbols in data sections that may refer to any init/exit sections */
933 if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
934 match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
935 match(fromsym, PATTERNS("*_ops", "*_probe", "*_console")))
936 return 0;
937
938 /* Check for pattern 3 */
939 if (strstarts(fromsec, ".head.text") &&
940 match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
941 return 0;
942
943 /* Check for pattern 4 */
944 if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
945 return 0;
946
947 /* Check for pattern 5 */
948 if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
949 match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
950 match(fromsym, PATTERNS("*.constprop.*")))
951 return 0;
952
953 return 1;
954}
955
956static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
957 unsigned int secndx)
958{
959 return symsearch_find_nearest(elf, addr, secndx, false, ~0);
960}
961
962static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
963{
964 Elf_Sym *new_sym;
965
966 /* If the supplied symbol has a valid name, return it */
967 if (is_valid_name(elf, sym))
968 return sym;
969
970 /*
971 * Strive to find a better symbol name, but the resulting name may not
972 * match the symbol referenced in the original code.
973 */
974 new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
975 true, 20);
976 return new_sym ? new_sym : sym;
977}
978
979static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
980{
981 if (secndx >= elf->num_sections)
982 return false;
983
984 return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
985}
986
987static void default_mismatch_handler(const char *modname, struct elf_info *elf,
988 const struct sectioncheck* const mismatch,
989 Elf_Sym *tsym,
990 unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
991 const char *tosec, Elf_Addr taddr)
992{
993 Elf_Sym *from;
994 const char *tosym;
995 const char *fromsym;
996 char taddr_str[16];
997
998 from = find_fromsym(elf, faddr, fsecndx);
999 fromsym = sym_name(elf, from);
1000
1001 tsym = find_tosym(elf, taddr, tsym);
1002 tosym = sym_name(elf, tsym);
1003
1004 /* check whitelist - we may ignore it */
1005 if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1006 return;
1007
1008 sec_mismatch_count++;
1009
1010 if (!tosym[0])
1011 snprintf(taddr_str, sizeof(taddr_str), "0x%x", (unsigned int)taddr);
1012
1013 /*
1014 * The format for the reference source: <symbol_name>+<offset> or <address>
1015 * The format for the reference destination: <symbol_name> or <address>
1016 */
1017 warn("%s: section mismatch in reference: %s%s0x%x (section: %s) -> %s (section: %s)\n",
1018 modname, fromsym, fromsym[0] ? "+" : "",
1019 (unsigned int)(faddr - (fromsym[0] ? from->st_value : 0)),
1020 fromsec, tosym[0] ? tosym : taddr_str, tosec);
1021
1022 if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1023 if (match(tosec, mismatch->bad_tosec))
1024 fatal("The relocation at %s+0x%lx references\n"
1025 "section \"%s\" which is black-listed.\n"
1026 "Something is seriously wrong and should be fixed.\n"
1027 "You might get more information about where this is\n"
1028 "coming from by using scripts/check_extable.sh %s\n",
1029 fromsec, (long)faddr, tosec, modname);
1030 else if (is_executable_section(elf, get_secindex(elf, tsym)))
1031 warn("The relocation at %s+0x%lx references\n"
1032 "section \"%s\" which is not in the list of\n"
1033 "authorized sections. If you're adding a new section\n"
1034 "and/or if this reference is valid, add \"%s\" to the\n"
1035 "list of authorized sections to jump to on fault.\n"
1036 "This can be achieved by adding \"%s\" to\n"
1037 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1038 fromsec, (long)faddr, tosec, tosec, tosec);
1039 else
1040 error("%s+0x%lx references non-executable section '%s'\n",
1041 fromsec, (long)faddr, tosec);
1042 }
1043}
1044
1045static void check_export_symbol(struct module *mod, struct elf_info *elf,
1046 Elf_Addr faddr, const char *secname,
1047 Elf_Sym *sym)
1048{
1049 static const char *prefix = "__export_symbol_";
1050 const char *label_name, *name, *data;
1051 Elf_Sym *label;
1052 struct symbol *s;
1053 bool is_gpl;
1054
1055 label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1056 label_name = sym_name(elf, label);
1057
1058 if (!strstarts(label_name, prefix)) {
1059 error("%s: .export_symbol section contains strange symbol '%s'\n",
1060 mod->name, label_name);
1061 return;
1062 }
1063
1064 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1065 ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1066 error("%s: local symbol '%s' was exported\n", mod->name,
1067 label_name + strlen(prefix));
1068 return;
1069 }
1070
1071 name = sym_name(elf, sym);
1072 if (strcmp(label_name + strlen(prefix), name)) {
1073 error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1074 mod->name, name);
1075 return;
1076 }
1077
1078 data = sym_get_data(elf, label); /* license */
1079 if (!strcmp(data, "GPL")) {
1080 is_gpl = true;
1081 } else if (!strcmp(data, "")) {
1082 is_gpl = false;
1083 } else {
1084 error("%s: unknown license '%s' was specified for '%s'\n",
1085 mod->name, data, name);
1086 return;
1087 }
1088
1089 data += strlen(data) + 1; /* namespace */
1090 s = sym_add_exported(name, mod, is_gpl, data);
1091
1092 /*
1093 * We need to be aware whether we are exporting a function or
1094 * a data on some architectures.
1095 */
1096 s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1097
1098 /*
1099 * For parisc64, symbols prefixed $$ from the library have the symbol type
1100 * STT_LOPROC. They should be handled as functions too.
1101 */
1102 if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
1103 elf->hdr->e_machine == EM_PARISC &&
1104 ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
1105 s->is_func = true;
1106
1107 if (match(secname, PATTERNS(ALL_INIT_SECTIONS)))
1108 warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1109 mod->name, name);
1110 else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS)))
1111 warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1112 mod->name, name);
1113}
1114
1115static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1116 Elf_Sym *sym,
1117 unsigned int fsecndx, const char *fromsec,
1118 Elf_Addr faddr, Elf_Addr taddr)
1119{
1120 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1121 const struct sectioncheck *mismatch;
1122
1123 if (module_enabled && elf->export_symbol_secndx == fsecndx) {
1124 check_export_symbol(mod, elf, faddr, tosec, sym);
1125 return;
1126 }
1127
1128 mismatch = section_mismatch(fromsec, tosec);
1129 if (!mismatch)
1130 return;
1131
1132 default_mismatch_handler(mod->name, elf, mismatch, sym,
1133 fsecndx, fromsec, faddr,
1134 tosec, taddr);
1135}
1136
1137static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
1138{
1139 switch (r_type) {
1140 case R_386_32:
1141 return get_unaligned_native(location);
1142 case R_386_PC32:
1143 return get_unaligned_native(location) + 4;
1144 }
1145
1146 return (Elf_Addr)(-1);
1147}
1148
1149static int32_t sign_extend32(int32_t value, int index)
1150{
1151 uint8_t shift = 31 - index;
1152
1153 return (int32_t)(value << shift) >> shift;
1154}
1155
1156static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
1157{
1158 uint32_t inst, upper, lower, sign, j1, j2;
1159 int32_t offset;
1160
1161 switch (r_type) {
1162 case R_ARM_ABS32:
1163 case R_ARM_REL32:
1164 inst = get_unaligned_native((uint32_t *)loc);
1165 return inst + sym->st_value;
1166 case R_ARM_MOVW_ABS_NC:
1167 case R_ARM_MOVT_ABS:
1168 inst = get_unaligned_native((uint32_t *)loc);
1169 offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1170 15);
1171 return offset + sym->st_value;
1172 case R_ARM_PC24:
1173 case R_ARM_CALL:
1174 case R_ARM_JUMP24:
1175 inst = get_unaligned_native((uint32_t *)loc);
1176 offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1177 return offset + sym->st_value + 8;
1178 case R_ARM_THM_MOVW_ABS_NC:
1179 case R_ARM_THM_MOVT_ABS:
1180 upper = get_unaligned_native((uint16_t *)loc);
1181 lower = get_unaligned_native((uint16_t *)loc + 1);
1182 offset = sign_extend32(((upper & 0x000f) << 12) |
1183 ((upper & 0x0400) << 1) |
1184 ((lower & 0x7000) >> 4) |
1185 (lower & 0x00ff),
1186 15);
1187 return offset + sym->st_value;
1188 case R_ARM_THM_JUMP19:
1189 /*
1190 * Encoding T3:
1191 * S = upper[10]
1192 * imm6 = upper[5:0]
1193 * J1 = lower[13]
1194 * J2 = lower[11]
1195 * imm11 = lower[10:0]
1196 * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1197 */
1198 upper = get_unaligned_native((uint16_t *)loc);
1199 lower = get_unaligned_native((uint16_t *)loc + 1);
1200
1201 sign = (upper >> 10) & 1;
1202 j1 = (lower >> 13) & 1;
1203 j2 = (lower >> 11) & 1;
1204 offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1205 ((upper & 0x03f) << 12) |
1206 ((lower & 0x07ff) << 1),
1207 20);
1208 return offset + sym->st_value + 4;
1209 case R_ARM_THM_PC22:
1210 case R_ARM_THM_JUMP24:
1211 /*
1212 * Encoding T4:
1213 * S = upper[10]
1214 * imm10 = upper[9:0]
1215 * J1 = lower[13]
1216 * J2 = lower[11]
1217 * imm11 = lower[10:0]
1218 * I1 = NOT(J1 XOR S)
1219 * I2 = NOT(J2 XOR S)
1220 * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1221 */
1222 upper = get_unaligned_native((uint16_t *)loc);
1223 lower = get_unaligned_native((uint16_t *)loc + 1);
1224
1225 sign = (upper >> 10) & 1;
1226 j1 = (lower >> 13) & 1;
1227 j2 = (lower >> 11) & 1;
1228 offset = sign_extend32((sign << 24) |
1229 ((~(j1 ^ sign) & 1) << 23) |
1230 ((~(j2 ^ sign) & 1) << 22) |
1231 ((upper & 0x03ff) << 12) |
1232 ((lower & 0x07ff) << 1),
1233 24);
1234 return offset + sym->st_value + 4;
1235 }
1236
1237 return (Elf_Addr)(-1);
1238}
1239
1240static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
1241{
1242 uint32_t inst;
1243
1244 inst = get_unaligned_native(location);
1245 switch (r_type) {
1246 case R_MIPS_LO16:
1247 return inst & 0xffff;
1248 case R_MIPS_26:
1249 return (inst & 0x03ffffff) << 2;
1250 case R_MIPS_32:
1251 return inst;
1252 }
1253 return (Elf_Addr)(-1);
1254}
1255
1256#ifndef EM_RISCV
1257#define EM_RISCV 243
1258#endif
1259
1260#ifndef R_RISCV_SUB32
1261#define R_RISCV_SUB32 39
1262#endif
1263
1264#ifndef EM_LOONGARCH
1265#define EM_LOONGARCH 258
1266#endif
1267
1268#ifndef R_LARCH_SUB32
1269#define R_LARCH_SUB32 55
1270#endif
1271
1272#ifndef R_LARCH_RELAX
1273#define R_LARCH_RELAX 100
1274#endif
1275
1276#ifndef R_LARCH_ALIGN
1277#define R_LARCH_ALIGN 102
1278#endif
1279
1280static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
1281 unsigned int *r_type, unsigned int *r_sym)
1282{
1283 typedef struct {
1284 Elf64_Word r_sym; /* Symbol index */
1285 unsigned char r_ssym; /* Special symbol for 2nd relocation */
1286 unsigned char r_type3; /* 3rd relocation type */
1287 unsigned char r_type2; /* 2nd relocation type */
1288 unsigned char r_type; /* 1st relocation type */
1289 } Elf64_Mips_R_Info;
1290
1291 bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
1292
1293 if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
1294 Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
1295
1296 *r_type = mips64_r_info->r_type;
1297 *r_sym = TO_NATIVE(mips64_r_info->r_sym);
1298 return;
1299 }
1300
1301 if (is_64bit)
1302 r_info = TO_NATIVE((Elf64_Xword)r_info);
1303 else
1304 r_info = TO_NATIVE((Elf32_Word)r_info);
1305
1306 *r_type = ELF_R_TYPE(r_info);
1307 *r_sym = ELF_R_SYM(r_info);
1308}
1309
1310static void section_rela(struct module *mod, struct elf_info *elf,
1311 unsigned int fsecndx, const char *fromsec,
1312 const Elf_Rela *start, const Elf_Rela *stop)
1313{
1314 const Elf_Rela *rela;
1315
1316 for (rela = start; rela < stop; rela++) {
1317 Elf_Sym *tsym;
1318 Elf_Addr taddr, r_offset;
1319 unsigned int r_type, r_sym;
1320
1321 r_offset = TO_NATIVE(rela->r_offset);
1322 get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
1323
1324 tsym = elf->symtab_start + r_sym;
1325 taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
1326
1327 switch (elf->hdr->e_machine) {
1328 case EM_RISCV:
1329 if (!strcmp("__ex_table", fromsec) &&
1330 r_type == R_RISCV_SUB32)
1331 continue;
1332 break;
1333 case EM_LOONGARCH:
1334 switch (r_type) {
1335 case R_LARCH_SUB32:
1336 if (!strcmp("__ex_table", fromsec))
1337 continue;
1338 break;
1339 case R_LARCH_RELAX:
1340 case R_LARCH_ALIGN:
1341 /* These relocs do not refer to symbols */
1342 continue;
1343 }
1344 break;
1345 }
1346
1347 check_section_mismatch(mod, elf, tsym,
1348 fsecndx, fromsec, r_offset, taddr);
1349 }
1350}
1351
1352static void section_rel(struct module *mod, struct elf_info *elf,
1353 unsigned int fsecndx, const char *fromsec,
1354 const Elf_Rel *start, const Elf_Rel *stop)
1355{
1356 const Elf_Rel *rel;
1357
1358 for (rel = start; rel < stop; rel++) {
1359 Elf_Sym *tsym;
1360 Elf_Addr taddr, r_offset;
1361 unsigned int r_type, r_sym;
1362 void *loc;
1363
1364 r_offset = TO_NATIVE(rel->r_offset);
1365 get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
1366
1367 loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
1368 tsym = elf->symtab_start + r_sym;
1369
1370 switch (elf->hdr->e_machine) {
1371 case EM_386:
1372 taddr = addend_386_rel(loc, r_type);
1373 break;
1374 case EM_ARM:
1375 taddr = addend_arm_rel(loc, tsym, r_type);
1376 break;
1377 case EM_MIPS:
1378 taddr = addend_mips_rel(loc, r_type);
1379 break;
1380 default:
1381 fatal("Please add code to calculate addend for this architecture\n");
1382 }
1383
1384 check_section_mismatch(mod, elf, tsym,
1385 fsecndx, fromsec, r_offset, taddr);
1386 }
1387}
1388
1389/**
1390 * A module includes a number of sections that are discarded
1391 * either when loaded or when used as built-in.
1392 * For loaded modules all functions marked __init and all data
1393 * marked __initdata will be discarded when the module has been initialized.
1394 * Likewise for modules used built-in the sections marked __exit
1395 * are discarded because __exit marked function are supposed to be called
1396 * only when a module is unloaded which never happens for built-in modules.
1397 * The check_sec_ref() function traverses all relocation records
1398 * to find all references to a section that reference a section that will
1399 * be discarded and warns about it.
1400 **/
1401static void check_sec_ref(struct module *mod, struct elf_info *elf)
1402{
1403 int i;
1404
1405 /* Walk through all sections */
1406 for (i = 0; i < elf->num_sections; i++) {
1407 Elf_Shdr *sechdr = &elf->sechdrs[i];
1408
1409 check_section(mod->name, elf, sechdr);
1410 /* We want to process only relocation sections and not .init */
1411 if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) {
1412 /* section to which the relocation applies */
1413 unsigned int secndx = sechdr->sh_info;
1414 const char *secname = sec_name(elf, secndx);
1415 const void *start, *stop;
1416
1417 /* If the section is known good, skip it */
1418 if (match(secname, section_white_list))
1419 continue;
1420
1421 start = sym_get_data_by_offset(elf, i, 0);
1422 stop = start + sechdr->sh_size;
1423
1424 if (sechdr->sh_type == SHT_RELA)
1425 section_rela(mod, elf, secndx, secname,
1426 start, stop);
1427 else
1428 section_rel(mod, elf, secndx, secname,
1429 start, stop);
1430 }
1431 }
1432}
1433
1434static char *remove_dot(char *s)
1435{
1436 size_t n = strcspn(s, ".");
1437
1438 if (n && s[n]) {
1439 size_t m = strspn(s + n + 1, "0123456789");
1440 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1441 s[n] = 0;
1442 }
1443 return s;
1444}
1445
1446/*
1447 * The CRCs are recorded in .*.cmd files in the form of:
1448 * #SYMVER <name> <crc>
1449 */
1450static void extract_crcs_for_object(const char *object, struct module *mod)
1451{
1452 char cmd_file[PATH_MAX];
1453 char *buf, *p;
1454 const char *base;
1455 int dirlen, ret;
1456
1457 base = strrchr(object, '/');
1458 if (base) {
1459 base++;
1460 dirlen = base - object;
1461 } else {
1462 dirlen = 0;
1463 base = object;
1464 }
1465
1466 ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
1467 dirlen, object, base);
1468 if (ret >= sizeof(cmd_file)) {
1469 error("%s: too long path was truncated\n", cmd_file);
1470 return;
1471 }
1472
1473 buf = read_text_file(cmd_file);
1474 p = buf;
1475
1476 while ((p = strstr(p, "\n#SYMVER "))) {
1477 char *name;
1478 size_t namelen;
1479 unsigned int crc;
1480 struct symbol *sym;
1481
1482 name = p + strlen("\n#SYMVER ");
1483
1484 p = strchr(name, ' ');
1485 if (!p)
1486 break;
1487
1488 namelen = p - name;
1489 p++;
1490
1491 if (!isdigit(*p))
1492 continue; /* skip this line */
1493
1494 crc = strtoul(p, &p, 0);
1495 if (*p != '\n')
1496 continue; /* skip this line */
1497
1498 name[namelen] = '\0';
1499
1500 /*
1501 * sym_find_with_module() may return NULL here.
1502 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1503 * Since commit e1327a127703, genksyms calculates CRCs of all
1504 * symbols, including trimmed ones. Ignore orphan CRCs.
1505 */
1506 sym = sym_find_with_module(name, mod);
1507 if (sym)
1508 sym_set_crc(sym, crc);
1509 }
1510
1511 free(buf);
1512}
1513
1514/*
1515 * The symbol versions (CRC) are recorded in the .*.cmd files.
1516 * Parse them to retrieve CRCs for the current module.
1517 */
1518static void mod_set_crcs(struct module *mod)
1519{
1520 char objlist[PATH_MAX];
1521 char *buf, *p, *obj;
1522 int ret;
1523
1524 if (mod->is_vmlinux) {
1525 strcpy(objlist, ".vmlinux.objs");
1526 } else {
1527 /* objects for a module are listed in the *.mod file. */
1528 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1529 if (ret >= sizeof(objlist)) {
1530 error("%s: too long path was truncated\n", objlist);
1531 return;
1532 }
1533 }
1534
1535 buf = read_text_file(objlist);
1536 p = buf;
1537
1538 while ((obj = strsep(&p, "\n")) && obj[0])
1539 extract_crcs_for_object(obj, mod);
1540
1541 free(buf);
1542}
1543
1544static void read_symbols(const char *modname)
1545{
1546 const char *symname;
1547 char *version;
1548 char *license;
1549 char *namespace;
1550 struct module *mod;
1551 struct elf_info info = { };
1552 Elf_Sym *sym;
1553
1554 if (!parse_elf(&info, modname))
1555 return;
1556
1557 if (!strends(modname, ".o")) {
1558 error("%s: filename must be suffixed with .o\n", modname);
1559 return;
1560 }
1561
1562 /* strip trailing .o */
1563 mod = new_module(modname, strlen(modname) - strlen(".o"));
1564
1565 if (!mod->is_vmlinux) {
1566 license = get_modinfo(&info, "license");
1567 if (!license)
1568 error("missing MODULE_LICENSE() in %s\n", modname);
1569 while (license) {
1570 if (!license_is_gpl_compatible(license)) {
1571 mod->is_gpl_compatible = false;
1572 break;
1573 }
1574 license = get_next_modinfo(&info, "license", license);
1575 }
1576
1577 namespace = get_modinfo(&info, "import_ns");
1578 while (namespace) {
1579 add_namespace(&mod->imported_namespaces, namespace);
1580 namespace = get_next_modinfo(&info, "import_ns",
1581 namespace);
1582 }
1583
1584 if (extra_warn && !get_modinfo(&info, "description"))
1585 warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1586 }
1587
1588 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1589 symname = remove_dot(info.strtab + sym->st_name);
1590
1591 handle_symbol(mod, &info, sym, symname);
1592 handle_moddevtable(mod, &info, sym, symname);
1593 }
1594
1595 check_sec_ref(mod, &info);
1596
1597 if (!mod->is_vmlinux) {
1598 version = get_modinfo(&info, "version");
1599 if (version || all_versions)
1600 get_src_version(mod->name, mod->srcversion,
1601 sizeof(mod->srcversion) - 1);
1602 }
1603
1604 parse_elf_finish(&info);
1605
1606 if (modversions) {
1607 /*
1608 * Our trick to get versioning for module struct etc. - it's
1609 * never passed as an argument to an exported function, so
1610 * the automatic versioning doesn't pick it up, but it's really
1611 * important anyhow.
1612 */
1613 sym_add_unresolved("module_layout", mod, false);
1614
1615 mod_set_crcs(mod);
1616 }
1617}
1618
1619static void read_symbols_from_files(const char *filename)
1620{
1621 FILE *in = stdin;
1622 char fname[PATH_MAX];
1623
1624 in = fopen(filename, "r");
1625 if (!in)
1626 fatal("Can't open filenames file %s: %m", filename);
1627
1628 while (fgets(fname, PATH_MAX, in) != NULL) {
1629 if (strends(fname, "\n"))
1630 fname[strlen(fname)-1] = '\0';
1631 read_symbols(fname);
1632 }
1633
1634 fclose(in);
1635}
1636
1637#define SZ 500
1638
1639/* We first write the generated file into memory using the
1640 * following helper, then compare to the file on disk and
1641 * only update the later if anything changed */
1642
1643void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1644 const char *fmt, ...)
1645{
1646 char tmp[SZ];
1647 int len;
1648 va_list ap;
1649
1650 va_start(ap, fmt);
1651 len = vsnprintf(tmp, SZ, fmt, ap);
1652 buf_write(buf, tmp, len);
1653 va_end(ap);
1654}
1655
1656void buf_write(struct buffer *buf, const char *s, int len)
1657{
1658 if (buf->size - buf->pos < len) {
1659 buf->size += len + SZ;
1660 buf->p = xrealloc(buf->p, buf->size);
1661 }
1662 strncpy(buf->p + buf->pos, s, len);
1663 buf->pos += len;
1664}
1665
1666static void check_exports(struct module *mod)
1667{
1668 struct symbol *s, *exp;
1669
1670 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1671 const char *basename;
1672 exp = find_symbol(s->name);
1673 if (!exp) {
1674 if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1675 modpost_log(!warn_unresolved,
1676 "\"%s\" [%s.ko] undefined!\n",
1677 s->name, mod->name);
1678 continue;
1679 }
1680 if (exp->module == mod) {
1681 error("\"%s\" [%s.ko] was exported without definition\n",
1682 s->name, mod->name);
1683 continue;
1684 }
1685
1686 exp->used = true;
1687 s->module = exp->module;
1688 s->crc_valid = exp->crc_valid;
1689 s->crc = exp->crc;
1690
1691 basename = strrchr(mod->name, '/');
1692 if (basename)
1693 basename++;
1694 else
1695 basename = mod->name;
1696
1697 if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1698 modpost_log(!allow_missing_ns_imports,
1699 "module %s uses symbol %s from namespace %s, but does not import it.\n",
1700 basename, exp->name, exp->namespace);
1701 add_namespace(&mod->missing_namespaces, exp->namespace);
1702 }
1703
1704 if (!mod->is_gpl_compatible && exp->is_gpl_only)
1705 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1706 basename, exp->name);
1707 }
1708}
1709
1710static void handle_white_list_exports(const char *white_list)
1711{
1712 char *buf, *p, *name;
1713
1714 buf = read_text_file(white_list);
1715 p = buf;
1716
1717 while ((name = strsep(&p, "\n"))) {
1718 struct symbol *sym = find_symbol(name);
1719
1720 if (sym)
1721 sym->used = true;
1722 }
1723
1724 free(buf);
1725}
1726
1727static void check_modname_len(struct module *mod)
1728{
1729 const char *mod_name;
1730
1731 mod_name = strrchr(mod->name, '/');
1732 if (mod_name == NULL)
1733 mod_name = mod->name;
1734 else
1735 mod_name++;
1736 if (strlen(mod_name) >= MODULE_NAME_LEN)
1737 error("module name is too long [%s.ko]\n", mod->name);
1738}
1739
1740/**
1741 * Header for the generated file
1742 **/
1743static void add_header(struct buffer *b, struct module *mod)
1744{
1745 buf_printf(b, "#include <linux/module.h>\n");
1746 buf_printf(b, "#include <linux/export-internal.h>\n");
1747 buf_printf(b, "#include <linux/compiler.h>\n");
1748 buf_printf(b, "\n");
1749 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1750 buf_printf(b, "\n");
1751 buf_printf(b, "__visible struct module __this_module\n");
1752 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1753 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1754 if (mod->has_init)
1755 buf_printf(b, "\t.init = init_module,\n");
1756 if (mod->has_cleanup)
1757 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1758 "\t.exit = cleanup_module,\n"
1759 "#endif\n");
1760 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1761 buf_printf(b, "};\n");
1762
1763 if (!external_module)
1764 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1765
1766 if (strstarts(mod->name, "drivers/staging"))
1767 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1768
1769 if (strstarts(mod->name, "tools/testing"))
1770 buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1771}
1772
1773static void add_exported_symbols(struct buffer *buf, struct module *mod)
1774{
1775 struct symbol *sym;
1776
1777 /* generate struct for exported symbols */
1778 buf_printf(buf, "\n");
1779 list_for_each_entry(sym, &mod->exported_symbols, list) {
1780 if (trim_unused_exports && !sym->used)
1781 continue;
1782
1783 buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1784 sym->is_func ? "FUNC" : "DATA", sym->name,
1785 sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1786 }
1787
1788 if (!modversions)
1789 return;
1790
1791 /* record CRCs for exported symbols */
1792 buf_printf(buf, "\n");
1793 list_for_each_entry(sym, &mod->exported_symbols, list) {
1794 if (trim_unused_exports && !sym->used)
1795 continue;
1796
1797 if (!sym->crc_valid)
1798 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1799 "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1800 sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1801 sym->name);
1802
1803 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1804 sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1805 }
1806}
1807
1808/**
1809 * Record CRCs for unresolved symbols
1810 **/
1811static void add_versions(struct buffer *b, struct module *mod)
1812{
1813 struct symbol *s;
1814
1815 if (!modversions)
1816 return;
1817
1818 buf_printf(b, "\n");
1819 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1820 buf_printf(b, "__used __section(\"__versions\") = {\n");
1821
1822 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1823 if (!s->module)
1824 continue;
1825 if (!s->crc_valid) {
1826 warn("\"%s\" [%s.ko] has no CRC!\n",
1827 s->name, mod->name);
1828 continue;
1829 }
1830 if (strlen(s->name) >= MODULE_NAME_LEN) {
1831 error("too long symbol \"%s\" [%s.ko]\n",
1832 s->name, mod->name);
1833 break;
1834 }
1835 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
1836 s->crc, s->name);
1837 }
1838
1839 buf_printf(b, "};\n");
1840}
1841
1842static void add_depends(struct buffer *b, struct module *mod)
1843{
1844 struct symbol *s;
1845 int first = 1;
1846
1847 /* Clear ->seen flag of modules that own symbols needed by this. */
1848 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1849 if (s->module)
1850 s->module->seen = s->module->is_vmlinux;
1851 }
1852
1853 buf_printf(b, "\n");
1854 buf_printf(b, "MODULE_INFO(depends, \"");
1855 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1856 const char *p;
1857 if (!s->module)
1858 continue;
1859
1860 if (s->module->seen)
1861 continue;
1862
1863 s->module->seen = true;
1864 p = strrchr(s->module->name, '/');
1865 if (p)
1866 p++;
1867 else
1868 p = s->module->name;
1869 buf_printf(b, "%s%s", first ? "" : ",", p);
1870 first = 0;
1871 }
1872 buf_printf(b, "\");\n");
1873}
1874
1875static void add_srcversion(struct buffer *b, struct module *mod)
1876{
1877 if (mod->srcversion[0]) {
1878 buf_printf(b, "\n");
1879 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1880 mod->srcversion);
1881 }
1882}
1883
1884static void write_buf(struct buffer *b, const char *fname)
1885{
1886 FILE *file;
1887
1888 if (error_occurred)
1889 return;
1890
1891 file = fopen(fname, "w");
1892 if (!file) {
1893 perror(fname);
1894 exit(1);
1895 }
1896 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1897 perror(fname);
1898 exit(1);
1899 }
1900 if (fclose(file) != 0) {
1901 perror(fname);
1902 exit(1);
1903 }
1904}
1905
1906static void write_if_changed(struct buffer *b, const char *fname)
1907{
1908 char *tmp;
1909 FILE *file;
1910 struct stat st;
1911
1912 file = fopen(fname, "r");
1913 if (!file)
1914 goto write;
1915
1916 if (fstat(fileno(file), &st) < 0)
1917 goto close_write;
1918
1919 if (st.st_size != b->pos)
1920 goto close_write;
1921
1922 tmp = xmalloc(b->pos);
1923 if (fread(tmp, 1, b->pos, file) != b->pos)
1924 goto free_write;
1925
1926 if (memcmp(tmp, b->p, b->pos) != 0)
1927 goto free_write;
1928
1929 free(tmp);
1930 fclose(file);
1931 return;
1932
1933 free_write:
1934 free(tmp);
1935 close_write:
1936 fclose(file);
1937 write:
1938 write_buf(b, fname);
1939}
1940
1941static void write_vmlinux_export_c_file(struct module *mod)
1942{
1943 struct buffer buf = { };
1944
1945 buf_printf(&buf,
1946 "#include <linux/export-internal.h>\n");
1947
1948 add_exported_symbols(&buf, mod);
1949 write_if_changed(&buf, ".vmlinux.export.c");
1950 free(buf.p);
1951}
1952
1953/* do sanity checks, and generate *.mod.c file */
1954static void write_mod_c_file(struct module *mod)
1955{
1956 struct buffer buf = { };
1957 struct module_alias *alias, *next;
1958 char fname[PATH_MAX];
1959 int ret;
1960
1961 add_header(&buf, mod);
1962 add_exported_symbols(&buf, mod);
1963 add_versions(&buf, mod);
1964 add_depends(&buf, mod);
1965
1966 buf_printf(&buf, "\n");
1967 list_for_each_entry_safe(alias, next, &mod->aliases, node) {
1968 buf_printf(&buf, "MODULE_ALIAS(\"%s\");\n", alias->str);
1969 list_del(&alias->node);
1970 free(alias);
1971 }
1972
1973 add_srcversion(&buf, mod);
1974
1975 ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
1976 if (ret >= sizeof(fname)) {
1977 error("%s: too long path was truncated\n", fname);
1978 goto free;
1979 }
1980
1981 write_if_changed(&buf, fname);
1982
1983free:
1984 free(buf.p);
1985}
1986
1987/* parse Module.symvers file. line format:
1988 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
1989 **/
1990static void read_dump(const char *fname)
1991{
1992 char *buf, *pos, *line;
1993
1994 buf = read_text_file(fname);
1995 if (!buf)
1996 /* No symbol versions, silently ignore */
1997 return;
1998
1999 pos = buf;
2000
2001 while ((line = get_line(&pos))) {
2002 char *symname, *namespace, *modname, *d, *export;
2003 unsigned int crc;
2004 struct module *mod;
2005 struct symbol *s;
2006 bool gpl_only;
2007
2008 if (!(symname = strchr(line, '\t')))
2009 goto fail;
2010 *symname++ = '\0';
2011 if (!(modname = strchr(symname, '\t')))
2012 goto fail;
2013 *modname++ = '\0';
2014 if (!(export = strchr(modname, '\t')))
2015 goto fail;
2016 *export++ = '\0';
2017 if (!(namespace = strchr(export, '\t')))
2018 goto fail;
2019 *namespace++ = '\0';
2020
2021 crc = strtoul(line, &d, 16);
2022 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2023 goto fail;
2024
2025 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2026 gpl_only = true;
2027 } else if (!strcmp(export, "EXPORT_SYMBOL")) {
2028 gpl_only = false;
2029 } else {
2030 error("%s: unknown license %s. skip", symname, export);
2031 continue;
2032 }
2033
2034 mod = find_module(fname, modname);
2035 if (!mod) {
2036 mod = new_module(modname, strlen(modname));
2037 mod->dump_file = fname;
2038 }
2039 s = sym_add_exported(symname, mod, gpl_only, namespace);
2040 sym_set_crc(s, crc);
2041 }
2042 free(buf);
2043 return;
2044fail:
2045 free(buf);
2046 fatal("parse error in symbol dump file\n");
2047}
2048
2049static void write_dump(const char *fname)
2050{
2051 struct buffer buf = { };
2052 struct module *mod;
2053 struct symbol *sym;
2054
2055 list_for_each_entry(mod, &modules, list) {
2056 if (mod->dump_file)
2057 continue;
2058 list_for_each_entry(sym, &mod->exported_symbols, list) {
2059 if (trim_unused_exports && !sym->used)
2060 continue;
2061
2062 buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2063 sym->crc, sym->name, mod->name,
2064 sym->is_gpl_only ? "_GPL" : "",
2065 sym->namespace);
2066 }
2067 }
2068 write_buf(&buf, fname);
2069 free(buf.p);
2070}
2071
2072static void write_namespace_deps_files(const char *fname)
2073{
2074 struct module *mod;
2075 struct namespace_list *ns;
2076 struct buffer ns_deps_buf = {};
2077
2078 list_for_each_entry(mod, &modules, list) {
2079
2080 if (mod->dump_file || list_empty(&mod->missing_namespaces))
2081 continue;
2082
2083 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2084
2085 list_for_each_entry(ns, &mod->missing_namespaces, list)
2086 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2087
2088 buf_printf(&ns_deps_buf, "\n");
2089 }
2090
2091 write_if_changed(&ns_deps_buf, fname);
2092 free(ns_deps_buf.p);
2093}
2094
2095struct dump_list {
2096 struct list_head list;
2097 const char *file;
2098};
2099
2100static void check_host_endian(void)
2101{
2102 static const union {
2103 short s;
2104 char c[2];
2105 } endian_test = { .c = {0x01, 0x02} };
2106
2107 switch (endian_test.s) {
2108 case 0x0102:
2109 host_is_big_endian = true;
2110 break;
2111 case 0x0201:
2112 host_is_big_endian = false;
2113 break;
2114 default:
2115 fatal("Unknown host endian\n");
2116 }
2117}
2118
2119int main(int argc, char **argv)
2120{
2121 struct module *mod;
2122 char *missing_namespace_deps = NULL;
2123 char *unused_exports_white_list = NULL;
2124 char *dump_write = NULL, *files_source = NULL;
2125 int opt;
2126 LIST_HEAD(dump_lists);
2127 struct dump_list *dl, *dl2;
2128
2129 while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
2130 switch (opt) {
2131 case 'e':
2132 external_module = true;
2133 break;
2134 case 'i':
2135 dl = xmalloc(sizeof(*dl));
2136 dl->file = optarg;
2137 list_add_tail(&dl->list, &dump_lists);
2138 break;
2139 case 'M':
2140 module_enabled = true;
2141 break;
2142 case 'm':
2143 modversions = true;
2144 break;
2145 case 'n':
2146 ignore_missing_files = true;
2147 break;
2148 case 'o':
2149 dump_write = optarg;
2150 break;
2151 case 'a':
2152 all_versions = true;
2153 break;
2154 case 'T':
2155 files_source = optarg;
2156 break;
2157 case 't':
2158 trim_unused_exports = true;
2159 break;
2160 case 'u':
2161 unused_exports_white_list = optarg;
2162 break;
2163 case 'W':
2164 extra_warn = true;
2165 break;
2166 case 'w':
2167 warn_unresolved = true;
2168 break;
2169 case 'E':
2170 sec_mismatch_warn_only = false;
2171 break;
2172 case 'N':
2173 allow_missing_ns_imports = true;
2174 break;
2175 case 'd':
2176 missing_namespace_deps = optarg;
2177 break;
2178 default:
2179 exit(1);
2180 }
2181 }
2182
2183 check_host_endian();
2184
2185 list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2186 read_dump(dl->file);
2187 list_del(&dl->list);
2188 free(dl);
2189 }
2190
2191 while (optind < argc)
2192 read_symbols(argv[optind++]);
2193
2194 if (files_source)
2195 read_symbols_from_files(files_source);
2196
2197 list_for_each_entry(mod, &modules, list) {
2198 if (mod->dump_file || mod->is_vmlinux)
2199 continue;
2200
2201 check_modname_len(mod);
2202 check_exports(mod);
2203 }
2204
2205 if (unused_exports_white_list)
2206 handle_white_list_exports(unused_exports_white_list);
2207
2208 list_for_each_entry(mod, &modules, list) {
2209 if (mod->dump_file)
2210 continue;
2211
2212 if (mod->is_vmlinux)
2213 write_vmlinux_export_c_file(mod);
2214 else
2215 write_mod_c_file(mod);
2216 }
2217
2218 if (missing_namespace_deps)
2219 write_namespace_deps_files(missing_namespace_deps);
2220
2221 if (dump_write)
2222 write_dump(dump_write);
2223 if (sec_mismatch_count && !sec_mismatch_warn_only)
2224 error("Section mismatches detected.\n"
2225 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2226
2227 if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2228 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2229 nr_unresolved - MAX_UNRESOLVED_REPORTS);
2230
2231 return error_occurred ? 1 : 0;
2232}