xref: /linux/scripts/mod/modpost.c (revision 29c52907334a8e50ba1ee5fbaa53407dec28d876)
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 
31 #define MODULE_NS_PREFIX "module:"
32 
33 static bool module_enabled;
34 /* Are we using CONFIG_MODVERSIONS? */
35 static bool modversions;
36 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
37 static bool all_versions;
38 /* Is CONFIG_BASIC_MODVERSIONS set? */
39 static bool basic_modversions;
40 /* Is CONFIG_EXTENDED_MODVERSIONS set? */
41 static bool extended_modversions;
42 /* If we are modposting external module set to 1 */
43 static bool external_module;
44 /* Only warn about unresolved symbols */
45 static bool warn_unresolved;
46 
47 static int sec_mismatch_count;
48 static bool sec_mismatch_warn_only = true;
49 /* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
50 static bool trim_unused_exports;
51 
52 /* ignore missing files */
53 static bool ignore_missing_files;
54 /* If set to 1, only warn (instead of error) about missing ns imports */
55 static bool allow_missing_ns_imports;
56 
57 static bool error_occurred;
58 
59 static bool extra_warn __attribute__((unused));
60 
61 bool target_is_big_endian;
62 bool host_is_big_endian;
63 
64 /*
65  * Cut off the warnings when there are too many. This typically occurs when
66  * vmlinux is missing. ('make modules' without building vmlinux.)
67  */
68 #define MAX_UNRESOLVED_REPORTS	10
69 static unsigned int nr_unresolved;
70 
71 /* In kernel, this size is defined in linux/module.h;
72  * here we use Elf_Addr instead of long for covering cross-compile
73  */
74 
75 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
76 
77 void modpost_log(bool is_error, const char *fmt, ...)
78 {
79 	va_list arglist;
80 
81 	if (is_error) {
82 		fprintf(stderr, "ERROR: ");
83 		error_occurred = true;
84 	} else {
85 		fprintf(stderr, "WARNING: ");
86 	}
87 
88 	fprintf(stderr, "modpost: ");
89 
90 	va_start(arglist, fmt);
91 	vfprintf(stderr, fmt, arglist);
92 	va_end(arglist);
93 }
94 
95 static inline bool strends(const char *str, const char *postfix)
96 {
97 	if (strlen(str) < strlen(postfix))
98 		return false;
99 
100 	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
101 }
102 
103 /**
104  * get_basename - return the last part of a pathname.
105  *
106  * @path: path to extract the filename from.
107  */
108 const char *get_basename(const char *path)
109 {
110 	const char *tail = strrchr(path, '/');
111 
112 	return tail ? tail + 1 : path;
113 }
114 
115 char *read_text_file(const char *filename)
116 {
117 	struct stat st;
118 	size_t nbytes;
119 	int fd;
120 	char *buf;
121 
122 	fd = open(filename, O_RDONLY);
123 	if (fd < 0) {
124 		perror(filename);
125 		exit(1);
126 	}
127 
128 	if (fstat(fd, &st) < 0) {
129 		perror(filename);
130 		exit(1);
131 	}
132 
133 	buf = xmalloc(st.st_size + 1);
134 
135 	nbytes = st.st_size;
136 
137 	while (nbytes) {
138 		ssize_t bytes_read;
139 
140 		bytes_read = read(fd, buf, nbytes);
141 		if (bytes_read < 0) {
142 			perror(filename);
143 			exit(1);
144 		}
145 
146 		nbytes -= bytes_read;
147 	}
148 	buf[st.st_size] = '\0';
149 
150 	close(fd);
151 
152 	return buf;
153 }
154 
155 char *get_line(char **stringp)
156 {
157 	char *orig = *stringp, *next;
158 
159 	/* do not return the unwanted extra line at EOF */
160 	if (!orig || *orig == '\0')
161 		return NULL;
162 
163 	/* don't use strsep here, it is not available everywhere */
164 	next = strchr(orig, '\n');
165 	if (next)
166 		*next++ = '\0';
167 
168 	*stringp = next;
169 
170 	return orig;
171 }
172 
173 /* A list of all modules we processed */
174 LIST_HEAD(modules);
175 
176 static struct module *find_module(const char *filename, const char *modname)
177 {
178 	struct module *mod;
179 
180 	list_for_each_entry(mod, &modules, list) {
181 		if (!strcmp(mod->dump_file, filename) &&
182 		    !strcmp(mod->name, modname))
183 			return mod;
184 	}
185 	return NULL;
186 }
187 
188 static struct module *new_module(const char *name, size_t namelen)
189 {
190 	struct module *mod;
191 
192 	mod = xmalloc(sizeof(*mod) + namelen + 1);
193 	memset(mod, 0, sizeof(*mod));
194 
195 	INIT_LIST_HEAD(&mod->exported_symbols);
196 	INIT_LIST_HEAD(&mod->unresolved_symbols);
197 	INIT_LIST_HEAD(&mod->missing_namespaces);
198 	INIT_LIST_HEAD(&mod->imported_namespaces);
199 	INIT_LIST_HEAD(&mod->aliases);
200 
201 	memcpy(mod->name, name, namelen);
202 	mod->name[namelen] = '\0';
203 	mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
204 
205 	/*
206 	 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
207 	 * is missing, do not check the use for EXPORT_SYMBOL_GPL() because
208 	 * modpost will exit with an error anyway.
209 	 */
210 	mod->is_gpl_compatible = true;
211 
212 	list_add_tail(&mod->list, &modules);
213 
214 	return mod;
215 }
216 
217 struct symbol {
218 	struct hlist_node hnode;/* link to hash table */
219 	struct list_head list;	/* link to module::exported_symbols or module::unresolved_symbols */
220 	struct module *module;
221 	char *namespace;
222 	unsigned int crc;
223 	bool crc_valid;
224 	bool weak;
225 	bool is_func;
226 	bool is_gpl_only;	/* exported by EXPORT_SYMBOL_GPL */
227 	bool used;		/* there exists a user of this symbol */
228 	char name[];
229 };
230 
231 static HASHTABLE_DEFINE(symbol_hashtable, 1U << 10);
232 
233 /**
234  * Allocate a new symbols for use in the hash of exported symbols or
235  * the list of unresolved symbols per module
236  **/
237 static struct symbol *alloc_symbol(const char *name)
238 {
239 	struct symbol *s = xmalloc(sizeof(*s) + strlen(name) + 1);
240 
241 	memset(s, 0, sizeof(*s));
242 	strcpy(s->name, name);
243 
244 	return s;
245 }
246 
247 static uint8_t get_symbol_flags(const struct symbol *sym)
248 {
249 	return sym->is_gpl_only ? KSYM_FLAG_GPL_ONLY : 0;
250 }
251 
252 /* For the hash of exported symbols */
253 static void hash_add_symbol(struct symbol *sym)
254 {
255 	hash_add(symbol_hashtable, &sym->hnode, hash_str(sym->name));
256 }
257 
258 static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
259 {
260 	struct symbol *sym;
261 
262 	sym = alloc_symbol(name);
263 	sym->weak = weak;
264 
265 	list_add_tail(&sym->list, &mod->unresolved_symbols);
266 }
267 
268 static struct symbol *sym_find_with_module(const char *name, struct module *mod)
269 {
270 	struct symbol *s;
271 
272 	/* For our purposes, .foo matches foo.  PPC64 needs this. */
273 	if (name[0] == '.')
274 		name++;
275 
276 	hash_for_each_possible(symbol_hashtable, s, hnode, hash_str(name)) {
277 		if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
278 			return s;
279 	}
280 	return NULL;
281 }
282 
283 static struct symbol *find_symbol(const char *name)
284 {
285 	return sym_find_with_module(name, NULL);
286 }
287 
288 struct namespace_list {
289 	struct list_head list;
290 	char namespace[];
291 };
292 
293 static bool contains_namespace(struct list_head *head, const char *namespace)
294 {
295 	struct namespace_list *list;
296 
297 	/*
298 	 * The default namespace is null string "", which is always implicitly
299 	 * contained.
300 	 */
301 	if (!namespace[0])
302 		return true;
303 
304 	list_for_each_entry(list, head, list) {
305 		if (!strcmp(list->namespace, namespace))
306 			return true;
307 	}
308 
309 	return false;
310 }
311 
312 static void add_namespace(struct list_head *head, const char *namespace)
313 {
314 	struct namespace_list *ns_entry;
315 
316 	if (!contains_namespace(head, namespace)) {
317 		ns_entry = xmalloc(sizeof(*ns_entry) + strlen(namespace) + 1);
318 		strcpy(ns_entry->namespace, namespace);
319 		list_add_tail(&ns_entry->list, head);
320 	}
321 }
322 
323 static void *sym_get_data_by_offset(const struct elf_info *info,
324 				    unsigned int secindex, unsigned long offset)
325 {
326 	Elf_Shdr *sechdr = &info->sechdrs[secindex];
327 
328 	return (void *)info->hdr + sechdr->sh_offset + offset;
329 }
330 
331 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
332 {
333 	return sym_get_data_by_offset(info, get_secindex(info, sym),
334 				      sym->st_value);
335 }
336 
337 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
338 {
339 	return sym_get_data_by_offset(info, info->secindex_strings,
340 				      sechdr->sh_name);
341 }
342 
343 static const char *sec_name(const struct elf_info *info, unsigned int secindex)
344 {
345 	/*
346 	 * If sym->st_shndx is a special section index, there is no
347 	 * corresponding section header.
348 	 * Return "" if the index is out of range of info->sechdrs[] array.
349 	 */
350 	if (secindex >= info->num_sections)
351 		return "";
352 
353 	return sech_name(info, &info->sechdrs[secindex]);
354 }
355 
356 static struct symbol *sym_add_exported(const char *name, struct module *mod,
357 				       bool gpl_only, const char *namespace)
358 {
359 	struct symbol *s = find_symbol(name);
360 
361 	if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
362 		error("%s: '%s' exported twice. Previous export was in %s%s\n",
363 		      mod->name, name, s->module->name,
364 		      s->module->is_vmlinux ? "" : ".ko");
365 	}
366 
367 	s = alloc_symbol(name);
368 	s->module = mod;
369 	s->is_gpl_only = gpl_only;
370 	s->namespace = xstrdup(namespace);
371 	list_add_tail(&s->list, &mod->exported_symbols);
372 	hash_add_symbol(s);
373 
374 	return s;
375 }
376 
377 static void sym_set_crc(struct symbol *sym, unsigned int crc)
378 {
379 	sym->crc = crc;
380 	sym->crc_valid = true;
381 }
382 
383 static void *grab_file(const char *filename, size_t *size)
384 {
385 	struct stat st;
386 	void *map = MAP_FAILED;
387 	int fd;
388 
389 	fd = open(filename, O_RDONLY);
390 	if (fd < 0)
391 		return NULL;
392 	if (fstat(fd, &st))
393 		goto failed;
394 
395 	*size = st.st_size;
396 	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
397 
398 failed:
399 	close(fd);
400 	if (map == MAP_FAILED)
401 		return NULL;
402 	return map;
403 }
404 
405 static void release_file(void *file, size_t size)
406 {
407 	munmap(file, size);
408 }
409 
410 static int parse_elf(struct elf_info *info, const char *filename)
411 {
412 	unsigned int i;
413 	Elf_Ehdr *hdr;
414 	Elf_Shdr *sechdrs;
415 	Elf_Sym  *sym;
416 	const char *secstrings;
417 	unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
418 
419 	hdr = grab_file(filename, &info->size);
420 	if (!hdr) {
421 		if (ignore_missing_files) {
422 			fprintf(stderr, "%s: %s (ignored)\n", filename,
423 				strerror(errno));
424 			return 0;
425 		}
426 		perror(filename);
427 		exit(1);
428 	}
429 	info->hdr = hdr;
430 	if (info->size < sizeof(*hdr)) {
431 		/* file too small, assume this is an empty .o file */
432 		return 0;
433 	}
434 	/* Is this a valid ELF file? */
435 	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
436 	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
437 	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
438 	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
439 		/* Not an ELF file - silently ignore it */
440 		return 0;
441 	}
442 
443 	switch (hdr->e_ident[EI_DATA]) {
444 	case ELFDATA2LSB:
445 		target_is_big_endian = false;
446 		break;
447 	case ELFDATA2MSB:
448 		target_is_big_endian = true;
449 		break;
450 	default:
451 		fatal("target endian is unknown\n");
452 	}
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 	/* modpost only works for relocatable objects */
472 	if (hdr->e_type != ET_REL)
473 		fatal("%s: not relocatable object.", filename);
474 
475 	/* Check if file offset is correct */
476 	if (hdr->e_shoff > info->size)
477 		fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
478 		      (unsigned long)hdr->e_shoff, filename, info->size);
479 
480 	if (hdr->e_shnum == SHN_UNDEF) {
481 		/*
482 		 * There are more than 64k sections,
483 		 * read count from .sh_size.
484 		 */
485 		info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
486 	}
487 	else {
488 		info->num_sections = hdr->e_shnum;
489 	}
490 	if (hdr->e_shstrndx == SHN_XINDEX) {
491 		info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
492 	}
493 	else {
494 		info->secindex_strings = hdr->e_shstrndx;
495 	}
496 
497 	/* Fix endianness in section headers */
498 	for (i = 0; i < info->num_sections; i++) {
499 		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
500 		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
501 		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
502 		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
503 		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
504 		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
505 		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
506 		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
507 		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
508 		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
509 	}
510 	/* Find symbol table. */
511 	secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
512 	for (i = 1; i < info->num_sections; i++) {
513 		const char *secname;
514 		int nobits = sechdrs[i].sh_type == SHT_NOBITS;
515 
516 		if (!nobits && sechdrs[i].sh_offset > info->size)
517 			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
518 			      filename, (unsigned long)sechdrs[i].sh_offset,
519 			      sizeof(*hdr));
520 
521 		secname = secstrings + sechdrs[i].sh_name;
522 		if (strcmp(secname, ".modinfo") == 0) {
523 			if (nobits)
524 				fatal("%s has NOBITS .modinfo\n", filename);
525 			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
526 			info->modinfo_len = sechdrs[i].sh_size;
527 		} else if (!strcmp(secname, ".export_symbol")) {
528 			info->export_symbol_secndx = i;
529 		} else if (!strcmp(secname, ".no_trim_symbol")) {
530 			info->no_trim_symbol = (void *)hdr + sechdrs[i].sh_offset;
531 			info->no_trim_symbol_len = sechdrs[i].sh_size;
532 		}
533 
534 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
535 			unsigned int sh_link_idx;
536 			symtab_idx = i;
537 			info->symtab_start = (void *)hdr +
538 			    sechdrs[i].sh_offset;
539 			info->symtab_stop  = (void *)hdr +
540 			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
541 			sh_link_idx = sechdrs[i].sh_link;
542 			info->strtab       = (void *)hdr +
543 			    sechdrs[sh_link_idx].sh_offset;
544 		}
545 
546 		/* 32bit section no. table? ("more than 64k sections") */
547 		if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
548 			symtab_shndx_idx = i;
549 			info->symtab_shndx_start = (void *)hdr +
550 			    sechdrs[i].sh_offset;
551 			info->symtab_shndx_stop  = (void *)hdr +
552 			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
553 		}
554 	}
555 	if (!info->symtab_start)
556 		fatal("%s has no symtab?\n", filename);
557 
558 	/* Fix endianness in symbols */
559 	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
560 		sym->st_shndx = TO_NATIVE(sym->st_shndx);
561 		sym->st_name  = TO_NATIVE(sym->st_name);
562 		sym->st_value = TO_NATIVE(sym->st_value);
563 		sym->st_size  = TO_NATIVE(sym->st_size);
564 	}
565 
566 	if (symtab_shndx_idx != ~0U) {
567 		Elf32_Word *p;
568 		if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
569 			fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
570 			      filename, sechdrs[symtab_shndx_idx].sh_link,
571 			      symtab_idx);
572 		/* Fix endianness */
573 		for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
574 		     p++)
575 			*p = TO_NATIVE(*p);
576 	}
577 
578 	symsearch_init(info);
579 
580 	return 1;
581 }
582 
583 static void parse_elf_finish(struct elf_info *info)
584 {
585 	symsearch_finish(info);
586 	release_file(info->hdr, info->size);
587 }
588 
589 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
590 {
591 	/* ignore __this_module, it will be resolved shortly */
592 	if (strcmp(symname, "__this_module") == 0)
593 		return 1;
594 	/* ignore global offset table */
595 	if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
596 		return 1;
597 	if (info->hdr->e_machine == EM_PPC)
598 		/* Special register function linked on all modules during final link of .ko */
599 		if (strstarts(symname, "_restgpr_") ||
600 		    strstarts(symname, "_savegpr_") ||
601 		    strstarts(symname, "_rest32gpr_") ||
602 		    strstarts(symname, "_save32gpr_") ||
603 		    strstarts(symname, "_restvr_") ||
604 		    strstarts(symname, "_savevr_"))
605 			return 1;
606 	if (info->hdr->e_machine == EM_PPC64)
607 		/* Special register function linked on all modules during final link of .ko */
608 		if (strstarts(symname, "_restgpr0_") ||
609 		    strstarts(symname, "_savegpr0_") ||
610 		    strstarts(symname, "_restgpr1_") ||
611 		    strstarts(symname, "_savegpr1_") ||
612 		    strstarts(symname, "_restfpr_") ||
613 		    strstarts(symname, "_savefpr_") ||
614 		    strstarts(symname, "_restvr_") ||
615 		    strstarts(symname, "_savevr_") ||
616 		    strcmp(symname, ".TOC.") == 0)
617 			return 1;
618 
619 	/* ignore linker-created section bounds variables */
620 	if (strstarts(symname, "__start_") || strstarts(symname, "__stop_"))
621 		return 1;
622 
623 	/* Do not ignore this symbol */
624 	return 0;
625 }
626 
627 static void handle_symbol(struct module *mod, struct elf_info *info,
628 			  const Elf_Sym *sym, const char *symname)
629 {
630 	switch (sym->st_shndx) {
631 	case SHN_COMMON:
632 		if (strstarts(symname, "__gnu_lto_")) {
633 			/* Should warn here, but modpost runs before the linker */
634 		} else
635 			warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
636 		break;
637 	case SHN_UNDEF:
638 		/* undefined symbol */
639 		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
640 		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
641 			break;
642 		if (ignore_undef_symbol(info, symname))
643 			break;
644 		if (info->hdr->e_machine == EM_SPARC ||
645 		    info->hdr->e_machine == EM_SPARCV9) {
646 			/* Ignore register directives. */
647 			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
648 				break;
649 			if (symname[0] == '.') {
650 				char *munged = xstrdup(symname);
651 				munged[0] = '_';
652 				munged[1] = toupper(munged[1]);
653 				symname = munged;
654 			}
655 		}
656 
657 		sym_add_unresolved(symname, mod,
658 				   ELF_ST_BIND(sym->st_info) == STB_WEAK);
659 		break;
660 	default:
661 		if (strcmp(symname, "init_module") == 0)
662 			mod->has_init = true;
663 		if (strcmp(symname, "cleanup_module") == 0)
664 			mod->has_cleanup = true;
665 		break;
666 	}
667 }
668 
669 /**
670  * Parse tag=value strings from .modinfo section
671  **/
672 static char *next_string(char *string, unsigned long *secsize)
673 {
674 	/* Skip non-zero chars */
675 	while (string[0]) {
676 		string++;
677 		if ((*secsize)-- <= 1)
678 			return NULL;
679 	}
680 
681 	/* Skip any zero padding. */
682 	while (!string[0]) {
683 		string++;
684 		if ((*secsize)-- <= 1)
685 			return NULL;
686 	}
687 	return string;
688 }
689 
690 static char *get_next_modinfo(struct elf_info *info, const char *tag,
691 			      char *prev)
692 {
693 	char *p;
694 	unsigned int taglen = strlen(tag);
695 	char *modinfo = info->modinfo;
696 	unsigned long size = info->modinfo_len;
697 
698 	if (prev) {
699 		size -= prev - modinfo;
700 		modinfo = next_string(prev, &size);
701 	}
702 
703 	for (p = modinfo; p; p = next_string(p, &size)) {
704 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
705 			return p + taglen + 1;
706 	}
707 	return NULL;
708 }
709 
710 static char *get_modinfo(struct elf_info *info, const char *tag)
711 
712 {
713 	return get_next_modinfo(info, tag, NULL);
714 }
715 
716 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
717 {
718 	return sym ? elf->strtab + sym->st_name : "";
719 }
720 
721 /*
722  * Check whether the 'string' argument matches one of the 'patterns',
723  * an array of shell wildcard patterns (glob).
724  *
725  * Return true is there is a match.
726  */
727 static bool match(const char *string, const char *const patterns[])
728 {
729 	const char *pattern;
730 
731 	while ((pattern = *patterns++)) {
732 		if (!fnmatch(pattern, string, 0))
733 			return true;
734 	}
735 
736 	return false;
737 }
738 
739 /* useful to pass patterns to match() directly */
740 #define PATTERNS(...) \
741 	({ \
742 		static const char *const patterns[] = {__VA_ARGS__, NULL}; \
743 		patterns; \
744 	})
745 
746 /* sections that we do not want to do full section mismatch check on */
747 static const char *const section_white_list[] =
748 {
749 	".comment*",
750 	".debug*",
751 	".zdebug*",		/* Compressed debug sections. */
752 	".GCC.command.line",	/* record-gcc-switches */
753 	".mdebug*",        /* alpha, score, mips etc. */
754 	".pdr",            /* alpha, score, mips etc. */
755 	".stab*",
756 	".note*",
757 	".got*",
758 	".toc*",
759 	".xt.prop",				 /* xtensa */
760 	".xt.lit",         /* xtensa */
761 	".arcextmap*",			/* arc */
762 	".gnu.linkonce.arcext*",	/* arc : modules */
763 	".cmem*",			/* EZchip */
764 	".fmt_slot*",			/* EZchip */
765 	".gnu.lto*",
766 	".discard.*",
767 	".llvm.call-graph-profile",	/* call graph */
768 	"__llvm_covfun",
769 	"__llvm_covmap",
770 	NULL
771 };
772 
773 /*
774  * This is used to find sections missing the SHF_ALLOC flag.
775  * The cause of this is often a section specified in assembler
776  * without "ax" / "aw".
777  */
778 static void check_section(const char *modname, struct elf_info *elf,
779 			  Elf_Shdr *sechdr)
780 {
781 	const char *sec = sech_name(elf, sechdr);
782 
783 	if (sechdr->sh_type == SHT_PROGBITS &&
784 	    !(sechdr->sh_flags & SHF_ALLOC) &&
785 	    !match(sec, section_white_list)) {
786 		warn("%s (%s): unexpected non-allocatable section.\n"
787 		     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
788 		     "Note that for example <linux/init.h> contains\n"
789 		     "section definitions for use in .S files.\n\n",
790 		     modname, sec);
791 	}
792 }
793 
794 
795 
796 #define ALL_INIT_DATA_SECTIONS \
797 	".init.setup", ".init.rodata", ".init.data"
798 
799 #define ALL_PCI_INIT_SECTIONS	\
800 	".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
801 	".pci_fixup_enable", ".pci_fixup_resume", \
802 	".pci_fixup_resume_early", ".pci_fixup_suspend"
803 
804 #define ALL_INIT_SECTIONS ".init.*"
805 #define ALL_EXIT_SECTIONS ".exit.*"
806 
807 #define DATA_SECTIONS ".data", ".data.rel"
808 #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
809 		".kprobes.text", ".cpuidle.text", ".noinstr.text", \
810 		".ltext", ".ltext.*"
811 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
812 		".fixup", ".entry.text", ".exception.text", \
813 		".coldtext", ".softirqentry.text", ".irqentry.text"
814 
815 #define ALL_TEXT_SECTIONS  ".init.text", ".exit.text", \
816 		TEXT_SECTIONS, OTHER_TEXT_SECTIONS
817 
818 enum mismatch {
819 	TEXTDATA_TO_ANY_INIT_EXIT,
820 	XXXINIT_TO_SOME_INIT,
821 	ANY_INIT_TO_ANY_EXIT,
822 	ANY_EXIT_TO_ANY_INIT,
823 	EXTABLE_TO_NON_TEXT,
824 };
825 
826 /**
827  * Describe how to match sections on different criteria:
828  *
829  * @fromsec: Array of sections to be matched.
830  *
831  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
832  * this array is forbidden (black-list).  Can be empty.
833  *
834  * @good_tosec: Relocations applied to a section in @fromsec must be
835  * targeting sections in this array (white-list).  Can be empty.
836  *
837  * @mismatch: Type of mismatch.
838  */
839 struct sectioncheck {
840 	const char *fromsec[20];
841 	const char *bad_tosec[20];
842 	const char *good_tosec[20];
843 	enum mismatch mismatch;
844 };
845 
846 static const struct sectioncheck sectioncheck[] = {
847 /* Do not reference init/exit code/data from
848  * normal code and data
849  */
850 {
851 	.fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
852 	.bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
853 	.mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
854 },
855 /* Do not use exit code/data from init code */
856 {
857 	.fromsec = { ALL_INIT_SECTIONS, NULL },
858 	.bad_tosec = { ALL_EXIT_SECTIONS, NULL },
859 	.mismatch = ANY_INIT_TO_ANY_EXIT,
860 },
861 /* Do not use init code/data from exit code */
862 {
863 	.fromsec = { ALL_EXIT_SECTIONS, NULL },
864 	.bad_tosec = { ALL_INIT_SECTIONS, NULL },
865 	.mismatch = ANY_EXIT_TO_ANY_INIT,
866 },
867 {
868 	.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
869 	.bad_tosec = { ALL_INIT_SECTIONS, NULL },
870 	.mismatch = ANY_INIT_TO_ANY_EXIT,
871 },
872 {
873 	.fromsec = { "__ex_table", NULL },
874 	/* If you're adding any new black-listed sections in here, consider
875 	 * adding a special 'printer' for them in scripts/check_extable.
876 	 */
877 	.bad_tosec = { ".altinstr_replacement", NULL },
878 	.good_tosec = {ALL_TEXT_SECTIONS , NULL},
879 	.mismatch = EXTABLE_TO_NON_TEXT,
880 }
881 };
882 
883 static const struct sectioncheck *section_mismatch(
884 		const char *fromsec, const char *tosec)
885 {
886 	int i;
887 
888 	/*
889 	 * The target section could be the SHT_NUL section when we're
890 	 * handling relocations to un-resolved symbols, trying to match it
891 	 * doesn't make much sense and causes build failures on parisc
892 	 * architectures.
893 	 */
894 	if (*tosec == '\0')
895 		return NULL;
896 
897 	for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
898 		const struct sectioncheck *check = &sectioncheck[i];
899 
900 		if (match(fromsec, check->fromsec)) {
901 			if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
902 				return check;
903 			if (check->good_tosec[0] && !match(tosec, check->good_tosec))
904 				return check;
905 		}
906 	}
907 	return NULL;
908 }
909 
910 /**
911  * Whitelist to allow certain references to pass with no warning.
912  *
913  * Pattern 1:
914  *   If a module parameter is declared __initdata and permissions=0
915  *   then this is legal despite the warning generated.
916  *   We cannot see value of permissions here, so just ignore
917  *   this pattern.
918  *   The pattern is identified by:
919  *   tosec   = .init.data
920  *   fromsec = .data*
921  *   atsym   =__param*
922  *
923  * Pattern 1a:
924  *   module_param_call() ops can refer to __init set function if permissions=0
925  *   The pattern is identified by:
926  *   tosec   = .init.text
927  *   fromsec = .data*
928  *   atsym   = __param_ops_*
929  *
930  * Pattern 3:
931  *   Whitelist all references from .head.text to any init section
932  *
933  * Pattern 4:
934  *   Some symbols belong to init section but still it is ok to reference
935  *   these from non-init sections as these symbols don't have any memory
936  *   allocated for them and symbol address and value are same. So even
937  *   if init section is freed, its ok to reference those symbols.
938  *   For ex. symbols marking the init section boundaries.
939  *   This pattern is identified by
940  *   refsymname = __init_begin, _sinittext, _einittext
941  *
942  * Pattern 5:
943  *   GCC may optimize static inlines when fed constant arg(s) resulting
944  *   in functions like cpumask_empty() -- generating an associated symbol
945  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
946  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
947  *   meaningless section warning.  May need to add isra symbols too...
948  *   This pattern is identified by
949  *   tosec   = init section
950  *   fromsec = text section
951  *   refsymname = *.constprop.*
952  *
953  **/
954 static int secref_whitelist(const char *fromsec, const char *fromsym,
955 			    const char *tosec, const char *tosym)
956 {
957 	/* Check for pattern 1 */
958 	if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
959 	    match(fromsec, PATTERNS(DATA_SECTIONS)) &&
960 	    strstarts(fromsym, "__param"))
961 		return 0;
962 
963 	/* Check for pattern 1a */
964 	if (strcmp(tosec, ".init.text") == 0 &&
965 	    match(fromsec, PATTERNS(DATA_SECTIONS)) &&
966 	    strstarts(fromsym, "__param_ops_"))
967 		return 0;
968 
969 	/* symbols in data sections that may refer to any init/exit sections */
970 	if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
971 	    match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
972 	    match(fromsym, PATTERNS("*_ops", "*_console")))
973 		return 0;
974 
975 	/* Check for pattern 3 */
976 	if (strstarts(fromsec, ".head.text") &&
977 	    match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
978 		return 0;
979 
980 	/* Check for pattern 4 */
981 	if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
982 		return 0;
983 
984 	/* Check for pattern 5 */
985 	if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
986 	    match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
987 	    match(fromsym, PATTERNS("*.constprop.*")))
988 		return 0;
989 
990 	return 1;
991 }
992 
993 static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
994 			     unsigned int secndx)
995 {
996 	return symsearch_find_nearest(elf, addr, secndx, false, ~0);
997 }
998 
999 static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
1000 {
1001 	Elf_Sym *new_sym;
1002 
1003 	/* If the supplied symbol has a valid name, return it */
1004 	if (is_valid_name(elf, sym))
1005 		return sym;
1006 
1007 	/*
1008 	 * Strive to find a better symbol name, but the resulting name may not
1009 	 * match the symbol referenced in the original code.
1010 	 */
1011 	new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
1012 					 true, 20);
1013 	return new_sym ? new_sym : sym;
1014 }
1015 
1016 static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
1017 {
1018 	if (secndx >= elf->num_sections)
1019 		return false;
1020 
1021 	return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
1022 }
1023 
1024 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1025 				     const struct sectioncheck* const mismatch,
1026 				     Elf_Sym *tsym,
1027 				     unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
1028 				     const char *tosec, Elf_Addr taddr)
1029 {
1030 	Elf_Sym *from;
1031 	const char *tosym;
1032 	const char *fromsym;
1033 	char taddr_str[16];
1034 
1035 	from = find_fromsym(elf, faddr, fsecndx);
1036 	fromsym = sym_name(elf, from);
1037 
1038 	tsym = find_tosym(elf, taddr, tsym);
1039 	tosym = sym_name(elf, tsym);
1040 
1041 	/* check whitelist - we may ignore it */
1042 	if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1043 		return;
1044 
1045 	sec_mismatch_count++;
1046 
1047 	if (!tosym[0])
1048 		snprintf(taddr_str, sizeof(taddr_str), "0x%x", (unsigned int)taddr);
1049 
1050 	/*
1051 	 * The format for the reference source:      <symbol_name>+<offset> or <address>
1052 	 * The format for the reference destination: <symbol_name>          or <address>
1053 	 */
1054 	warn("%s: section mismatch in reference: %s%s0x%x (section: %s) -> %s (section: %s)\n",
1055 	     modname, fromsym, fromsym[0] ? "+" : "",
1056 	     (unsigned int)(faddr - (fromsym[0] ? from->st_value : 0)),
1057 	     fromsec, tosym[0] ? tosym : taddr_str, tosec);
1058 
1059 	if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1060 		if (match(tosec, mismatch->bad_tosec))
1061 			fatal("The relocation at %s+0x%lx references\n"
1062 			      "section \"%s\" which is black-listed.\n"
1063 			      "Something is seriously wrong and should be fixed.\n"
1064 			      "You might get more information about where this is\n"
1065 			      "coming from by using scripts/check_extable.sh %s\n",
1066 			      fromsec, (long)faddr, tosec, modname);
1067 		else if (is_executable_section(elf, get_secindex(elf, tsym)))
1068 			warn("The relocation at %s+0x%lx references\n"
1069 			     "section \"%s\" which is not in the list of\n"
1070 			     "authorized sections.  If you're adding a new section\n"
1071 			     "and/or if this reference is valid, add \"%s\" to the\n"
1072 			     "list of authorized sections to jump to on fault.\n"
1073 			     "This can be achieved by adding \"%s\" to\n"
1074 			     "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1075 			     fromsec, (long)faddr, tosec, tosec, tosec);
1076 		else
1077 			error("%s+0x%lx references non-executable section '%s'\n",
1078 			      fromsec, (long)faddr, tosec);
1079 	}
1080 }
1081 
1082 static void check_export_symbol(struct module *mod, struct elf_info *elf,
1083 				Elf_Addr faddr, const char *secname,
1084 				Elf_Sym *sym)
1085 {
1086 	static const char *prefix = "__export_symbol_";
1087 	const char *label_name, *name, *data;
1088 	Elf_Sym *label;
1089 	struct symbol *s;
1090 	bool is_gpl;
1091 
1092 	label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1093 	label_name = sym_name(elf, label);
1094 
1095 	if (!strstarts(label_name, prefix)) {
1096 		error("%s: .export_symbol section contains strange symbol '%s'\n",
1097 		      mod->name, label_name);
1098 		return;
1099 	}
1100 
1101 	if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1102 	    ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1103 		error("%s: local symbol '%s' was exported\n", mod->name,
1104 		      label_name + strlen(prefix));
1105 		return;
1106 	}
1107 
1108 	name = sym_name(elf, sym);
1109 	if (strcmp(label_name + strlen(prefix), name)) {
1110 		error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1111 		      mod->name, name);
1112 		return;
1113 	}
1114 
1115 	data = sym_get_data(elf, label);	/* license */
1116 	if (!strcmp(data, "GPL")) {
1117 		is_gpl = true;
1118 	} else if (!strcmp(data, "")) {
1119 		is_gpl = false;
1120 	} else {
1121 		error("%s: unknown license '%s' was specified for '%s'\n",
1122 		      mod->name, data, name);
1123 		return;
1124 	}
1125 
1126 	data += strlen(data) + 1;	/* namespace */
1127 	s = sym_add_exported(name, mod, is_gpl, data);
1128 
1129 	/*
1130 	 * We need to be aware whether we are exporting a function or
1131 	 * a data on some architectures.
1132 	 */
1133 	s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1134 
1135 	/*
1136 	 * For parisc64, symbols prefixed $$ from the library have the symbol type
1137 	 * STT_LOPROC. They should be handled as functions too.
1138 	 */
1139 	if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
1140 	    elf->hdr->e_machine == EM_PARISC &&
1141 	    ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
1142 		s->is_func = true;
1143 
1144 	if (match(secname, PATTERNS(ALL_INIT_SECTIONS)))
1145 		warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1146 		     mod->name, name);
1147 	else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS)))
1148 		warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1149 		     mod->name, name);
1150 }
1151 
1152 static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1153 				   Elf_Sym *sym,
1154 				   unsigned int fsecndx, const char *fromsec,
1155 				   Elf_Addr faddr, Elf_Addr taddr)
1156 {
1157 	const char *tosec = sec_name(elf, get_secindex(elf, sym));
1158 	const struct sectioncheck *mismatch;
1159 
1160 	if (module_enabled && elf->export_symbol_secndx == fsecndx) {
1161 		check_export_symbol(mod, elf, faddr, tosec, sym);
1162 		return;
1163 	}
1164 
1165 	mismatch = section_mismatch(fromsec, tosec);
1166 	if (!mismatch)
1167 		return;
1168 
1169 	default_mismatch_handler(mod->name, elf, mismatch, sym,
1170 				 fsecndx, fromsec, faddr,
1171 				 tosec, taddr);
1172 }
1173 
1174 static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
1175 {
1176 	switch (r_type) {
1177 	case R_386_32:
1178 		return get_unaligned_native(location);
1179 	case R_386_PC32:
1180 		return get_unaligned_native(location) + 4;
1181 	}
1182 
1183 	return (Elf_Addr)(-1);
1184 }
1185 
1186 static int32_t sign_extend32(int32_t value, int index)
1187 {
1188 	uint8_t shift = 31 - index;
1189 
1190 	return (int32_t)(value << shift) >> shift;
1191 }
1192 
1193 static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
1194 {
1195 	uint32_t inst, upper, lower, sign, j1, j2;
1196 	int32_t offset;
1197 
1198 	switch (r_type) {
1199 	case R_ARM_ABS32:
1200 	case R_ARM_REL32:
1201 		inst = get_unaligned_native((uint32_t *)loc);
1202 		return inst + sym->st_value;
1203 	case R_ARM_MOVW_ABS_NC:
1204 	case R_ARM_MOVT_ABS:
1205 		inst = get_unaligned_native((uint32_t *)loc);
1206 		offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1207 				       15);
1208 		return offset + sym->st_value;
1209 	case R_ARM_PC24:
1210 	case R_ARM_CALL:
1211 	case R_ARM_JUMP24:
1212 		inst = get_unaligned_native((uint32_t *)loc);
1213 		offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1214 		return offset + sym->st_value + 8;
1215 	case R_ARM_THM_MOVW_ABS_NC:
1216 	case R_ARM_THM_MOVT_ABS:
1217 		upper = get_unaligned_native((uint16_t *)loc);
1218 		lower = get_unaligned_native((uint16_t *)loc + 1);
1219 		offset = sign_extend32(((upper & 0x000f) << 12) |
1220 				       ((upper & 0x0400) << 1) |
1221 				       ((lower & 0x7000) >> 4) |
1222 				       (lower & 0x00ff),
1223 				       15);
1224 		return offset + sym->st_value;
1225 	case R_ARM_THM_JUMP19:
1226 		/*
1227 		 * Encoding T3:
1228 		 * S     = upper[10]
1229 		 * imm6  = upper[5:0]
1230 		 * J1    = lower[13]
1231 		 * J2    = lower[11]
1232 		 * imm11 = lower[10:0]
1233 		 * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1234 		 */
1235 		upper = get_unaligned_native((uint16_t *)loc);
1236 		lower = get_unaligned_native((uint16_t *)loc + 1);
1237 
1238 		sign = (upper >> 10) & 1;
1239 		j1 = (lower >> 13) & 1;
1240 		j2 = (lower >> 11) & 1;
1241 		offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1242 				       ((upper & 0x03f) << 12) |
1243 				       ((lower & 0x07ff) << 1),
1244 				       20);
1245 		return offset + sym->st_value + 4;
1246 	case R_ARM_THM_PC22:
1247 	case R_ARM_THM_JUMP24:
1248 		/*
1249 		 * Encoding T4:
1250 		 * S     = upper[10]
1251 		 * imm10 = upper[9:0]
1252 		 * J1    = lower[13]
1253 		 * J2    = lower[11]
1254 		 * imm11 = lower[10:0]
1255 		 * I1    = NOT(J1 XOR S)
1256 		 * I2    = NOT(J2 XOR S)
1257 		 * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1258 		 */
1259 		upper = get_unaligned_native((uint16_t *)loc);
1260 		lower = get_unaligned_native((uint16_t *)loc + 1);
1261 
1262 		sign = (upper >> 10) & 1;
1263 		j1 = (lower >> 13) & 1;
1264 		j2 = (lower >> 11) & 1;
1265 		offset = sign_extend32((sign << 24) |
1266 				       ((~(j1 ^ sign) & 1) << 23) |
1267 				       ((~(j2 ^ sign) & 1) << 22) |
1268 				       ((upper & 0x03ff) << 12) |
1269 				       ((lower & 0x07ff) << 1),
1270 				       24);
1271 		return offset + sym->st_value + 4;
1272 	}
1273 
1274 	return (Elf_Addr)(-1);
1275 }
1276 
1277 static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
1278 {
1279 	uint32_t inst;
1280 
1281 	inst = get_unaligned_native(location);
1282 	switch (r_type) {
1283 	case R_MIPS_LO16:
1284 		return inst & 0xffff;
1285 	case R_MIPS_26:
1286 		return (inst & 0x03ffffff) << 2;
1287 	case R_MIPS_32:
1288 		return inst;
1289 	}
1290 	return (Elf_Addr)(-1);
1291 }
1292 
1293 #ifndef EM_RISCV
1294 #define EM_RISCV		243
1295 #endif
1296 
1297 #ifndef R_RISCV_SUB32
1298 #define R_RISCV_SUB32		39
1299 #endif
1300 
1301 #ifndef EM_LOONGARCH
1302 #define EM_LOONGARCH		258
1303 #endif
1304 
1305 #ifndef R_LARCH_SUB32
1306 #define R_LARCH_SUB32		55
1307 #endif
1308 
1309 #ifndef R_LARCH_RELAX
1310 #define R_LARCH_RELAX		100
1311 #endif
1312 
1313 #ifndef R_LARCH_ALIGN
1314 #define R_LARCH_ALIGN		102
1315 #endif
1316 
1317 static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
1318 				 unsigned int *r_type, unsigned int *r_sym)
1319 {
1320 	typedef struct {
1321 		Elf64_Word    r_sym;	/* Symbol index */
1322 		unsigned char r_ssym;	/* Special symbol for 2nd relocation */
1323 		unsigned char r_type3;	/* 3rd relocation type */
1324 		unsigned char r_type2;	/* 2nd relocation type */
1325 		unsigned char r_type;	/* 1st relocation type */
1326 	} Elf64_Mips_R_Info;
1327 
1328 	bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
1329 
1330 	if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
1331 		Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
1332 
1333 		*r_type = mips64_r_info->r_type;
1334 		*r_sym = TO_NATIVE(mips64_r_info->r_sym);
1335 		return;
1336 	}
1337 
1338 	if (is_64bit)
1339 		r_info = TO_NATIVE((Elf64_Xword)r_info);
1340 	else
1341 		r_info = TO_NATIVE((Elf32_Word)r_info);
1342 
1343 	*r_type = ELF_R_TYPE(r_info);
1344 	*r_sym = ELF_R_SYM(r_info);
1345 }
1346 
1347 static void section_rela(struct module *mod, struct elf_info *elf,
1348 			 unsigned int fsecndx, const char *fromsec,
1349 			 const Elf_Rela *start, const Elf_Rela *stop)
1350 {
1351 	const Elf_Rela *rela;
1352 
1353 	for (rela = start; rela < stop; rela++) {
1354 		Elf_Sym *tsym;
1355 		Elf_Addr taddr, r_offset;
1356 		unsigned int r_type, r_sym;
1357 
1358 		r_offset = TO_NATIVE(rela->r_offset);
1359 		get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
1360 
1361 		tsym = elf->symtab_start + r_sym;
1362 		taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
1363 
1364 		switch (elf->hdr->e_machine) {
1365 		case EM_RISCV:
1366 			if (!strcmp("__ex_table", fromsec) &&
1367 			    r_type == R_RISCV_SUB32)
1368 				continue;
1369 			break;
1370 		case EM_LOONGARCH:
1371 			switch (r_type) {
1372 			case R_LARCH_SUB32:
1373 				if (!strcmp("__ex_table", fromsec))
1374 					continue;
1375 				break;
1376 			case R_LARCH_RELAX:
1377 			case R_LARCH_ALIGN:
1378 				/* These relocs do not refer to symbols */
1379 				continue;
1380 			}
1381 			break;
1382 		}
1383 
1384 		check_section_mismatch(mod, elf, tsym,
1385 				       fsecndx, fromsec, r_offset, taddr);
1386 	}
1387 }
1388 
1389 static void section_rel(struct module *mod, struct elf_info *elf,
1390 			unsigned int fsecndx, const char *fromsec,
1391 			const Elf_Rel *start, const Elf_Rel *stop)
1392 {
1393 	const Elf_Rel *rel;
1394 
1395 	for (rel = start; rel < stop; rel++) {
1396 		Elf_Sym *tsym;
1397 		Elf_Addr taddr, r_offset;
1398 		unsigned int r_type, r_sym;
1399 		void *loc;
1400 
1401 		r_offset = TO_NATIVE(rel->r_offset);
1402 		get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
1403 
1404 		loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
1405 		tsym = elf->symtab_start + r_sym;
1406 
1407 		switch (elf->hdr->e_machine) {
1408 		case EM_386:
1409 			taddr = addend_386_rel(loc, r_type);
1410 			break;
1411 		case EM_ARM:
1412 			taddr = addend_arm_rel(loc, tsym, r_type);
1413 			break;
1414 		case EM_MIPS:
1415 			taddr = addend_mips_rel(loc, r_type);
1416 			break;
1417 		default:
1418 			fatal("Please add code to calculate addend for this architecture\n");
1419 		}
1420 
1421 		check_section_mismatch(mod, elf, tsym,
1422 				       fsecndx, fromsec, r_offset, taddr);
1423 	}
1424 }
1425 
1426 /**
1427  * A module includes a number of sections that are discarded
1428  * either when loaded or when used as built-in.
1429  * For loaded modules all functions marked __init and all data
1430  * marked __initdata will be discarded when the module has been initialized.
1431  * Likewise for modules used built-in the sections marked __exit
1432  * are discarded because __exit marked function are supposed to be called
1433  * only when a module is unloaded which never happens for built-in modules.
1434  * The check_sec_ref() function traverses all relocation records
1435  * to find all references to a section that reference a section that will
1436  * be discarded and warns about it.
1437  **/
1438 static void check_sec_ref(struct module *mod, struct elf_info *elf)
1439 {
1440 	int i;
1441 
1442 	/* Walk through all sections */
1443 	for (i = 0; i < elf->num_sections; i++) {
1444 		Elf_Shdr *sechdr = &elf->sechdrs[i];
1445 
1446 		check_section(mod->name, elf, sechdr);
1447 		/* We want to process only relocation sections and not .init */
1448 		if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) {
1449 			/* section to which the relocation applies */
1450 			unsigned int secndx = sechdr->sh_info;
1451 			const char *secname = sec_name(elf, secndx);
1452 			const void *start, *stop;
1453 
1454 			/* If the section is known good, skip it */
1455 			if (match(secname, section_white_list))
1456 				continue;
1457 
1458 			start = sym_get_data_by_offset(elf, i, 0);
1459 			stop = start + sechdr->sh_size;
1460 
1461 			if (sechdr->sh_type == SHT_RELA)
1462 				section_rela(mod, elf, secndx, secname,
1463 					     start, stop);
1464 			else
1465 				section_rel(mod, elf, secndx, secname,
1466 					    start, stop);
1467 		}
1468 	}
1469 }
1470 
1471 static char *remove_dot(char *s)
1472 {
1473 	size_t n = strcspn(s, ".");
1474 
1475 	if (n && s[n]) {
1476 		size_t m = strspn(s + n + 1, "0123456789");
1477 		if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1478 			s[n] = 0;
1479 	}
1480 	return s;
1481 }
1482 
1483 /*
1484  * The CRCs are recorded in .*.cmd files in the form of:
1485  * #SYMVER <name> <crc>
1486  */
1487 static void extract_crcs_for_object(const char *object, struct module *mod)
1488 {
1489 	char cmd_file[PATH_MAX];
1490 	char *buf, *p;
1491 	const char *base;
1492 	int dirlen, baselen_without_suffix, ret;
1493 
1494 	base = get_basename(object);
1495 	dirlen = base - object;
1496 
1497 	baselen_without_suffix = strlen(object) - dirlen - strlen(".o");
1498 
1499 	/*
1500 	 * When CONFIG_LTO_CLANG_THIN_DIST=y, the ELF is *.thinlto-native.o
1501 	 * but the symbol CRCs are recorded in *.o.cmd file.
1502 	 */
1503 	if (strends(object, ".thinlto-native.o"))
1504 		baselen_without_suffix -= strlen(".thinlto-native");
1505 
1506 	ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%.*s.o.cmd",
1507 		       dirlen, object, baselen_without_suffix, base);
1508 	if (ret >= sizeof(cmd_file)) {
1509 		error("%s: too long path was truncated\n", cmd_file);
1510 		return;
1511 	}
1512 
1513 	buf = read_text_file(cmd_file);
1514 	p = buf;
1515 
1516 	while ((p = strstr(p, "\n#SYMVER "))) {
1517 		char *name;
1518 		size_t namelen;
1519 		unsigned int crc;
1520 		struct symbol *sym;
1521 
1522 		name = p + strlen("\n#SYMVER ");
1523 
1524 		p = strchr(name, ' ');
1525 		if (!p)
1526 			break;
1527 
1528 		namelen = p - name;
1529 		p++;
1530 
1531 		if (!isdigit(*p))
1532 			continue;	/* skip this line */
1533 
1534 		crc = strtoul(p, &p, 0);
1535 		if (*p != '\n')
1536 			continue;	/* skip this line */
1537 
1538 		name[namelen] = '\0';
1539 
1540 		/*
1541 		 * sym_find_with_module() may return NULL here.
1542 		 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1543 		 * Since commit e1327a127703, genksyms calculates CRCs of all
1544 		 * symbols, including trimmed ones. Ignore orphan CRCs.
1545 		 */
1546 		sym = sym_find_with_module(name, mod);
1547 		if (sym)
1548 			sym_set_crc(sym, crc);
1549 	}
1550 
1551 	free(buf);
1552 }
1553 
1554 /*
1555  * The symbol versions (CRC) are recorded in the .*.cmd files.
1556  * Parse them to retrieve CRCs for the current module.
1557  */
1558 static void mod_set_crcs(struct module *mod)
1559 {
1560 	char objlist[PATH_MAX];
1561 	char *buf, *p, *obj;
1562 	int ret;
1563 
1564 	if (mod->is_vmlinux) {
1565 		strcpy(objlist, ".vmlinux.objs");
1566 	} else {
1567 		/* objects for a module are listed in the *.mod file. */
1568 		ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1569 		if (ret >= sizeof(objlist)) {
1570 			error("%s: too long path was truncated\n", objlist);
1571 			return;
1572 		}
1573 	}
1574 
1575 	buf = read_text_file(objlist);
1576 	p = buf;
1577 
1578 	while ((obj = strsep(&p, "\n")) && obj[0])
1579 		extract_crcs_for_object(obj, mod);
1580 
1581 	free(buf);
1582 }
1583 
1584 static void read_symbols(const char *modname)
1585 {
1586 	const char *symname;
1587 	char *version;
1588 	char *license;
1589 	char *namespace;
1590 	struct module *mod;
1591 	struct elf_info info = { };
1592 	Elf_Sym *sym;
1593 
1594 	if (!parse_elf(&info, modname))
1595 		return;
1596 
1597 	if (!strends(modname, ".o")) {
1598 		error("%s: filename must be suffixed with .o\n", modname);
1599 		return;
1600 	}
1601 
1602 	/* strip trailing .o */
1603 	mod = new_module(modname, strlen(modname) - strlen(".o"));
1604 
1605 	/* save .no_trim_symbol section for later use */
1606 	if (info.no_trim_symbol_len) {
1607 		mod->no_trim_symbol = xmalloc(info.no_trim_symbol_len);
1608 		memcpy(mod->no_trim_symbol, info.no_trim_symbol,
1609 		       info.no_trim_symbol_len);
1610 		mod->no_trim_symbol_len = info.no_trim_symbol_len;
1611 	}
1612 
1613 	if (!mod->is_vmlinux) {
1614 		license = get_modinfo(&info, "license");
1615 		if (!license)
1616 			error("missing MODULE_LICENSE() in %s\n", modname);
1617 		while (license) {
1618 			if (!license_is_gpl_compatible(license)) {
1619 				mod->is_gpl_compatible = false;
1620 				break;
1621 			}
1622 			license = get_next_modinfo(&info, "license", license);
1623 		}
1624 
1625 		for (namespace = get_modinfo(&info, "import_ns");
1626 		     namespace;
1627 		     namespace = get_next_modinfo(&info, "import_ns", namespace)) {
1628 			if (strstarts(namespace, MODULE_NS_PREFIX))
1629 				error("%s: explicitly importing namespace \"%s\" is not allowed.\n",
1630 				      mod->name, namespace);
1631 
1632 			add_namespace(&mod->imported_namespaces, namespace);
1633 		}
1634 
1635 		if (!get_modinfo(&info, "description"))
1636 			warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1637 	}
1638 
1639 	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1640 		symname = remove_dot(info.strtab + sym->st_name);
1641 
1642 		handle_symbol(mod, &info, sym, symname);
1643 		handle_moddevtable(mod, &info, sym, symname);
1644 	}
1645 
1646 	check_sec_ref(mod, &info);
1647 
1648 	if (!mod->is_vmlinux) {
1649 		version = get_modinfo(&info, "version");
1650 		if (version || all_versions)
1651 			get_src_version(mod->name, mod->srcversion,
1652 					sizeof(mod->srcversion) - 1);
1653 	}
1654 
1655 	parse_elf_finish(&info);
1656 
1657 	if (modversions) {
1658 		/*
1659 		 * Our trick to get versioning for module struct etc. - it's
1660 		 * never passed as an argument to an exported function, so
1661 		 * the automatic versioning doesn't pick it up, but it's really
1662 		 * important anyhow.
1663 		 */
1664 		sym_add_unresolved("module_layout", mod, false);
1665 
1666 		mod_set_crcs(mod);
1667 	}
1668 }
1669 
1670 static void read_symbols_from_files(const char *filename)
1671 {
1672 	FILE *in = stdin;
1673 	char fname[PATH_MAX];
1674 
1675 	in = fopen(filename, "r");
1676 	if (!in)
1677 		fatal("Can't open filenames file %s: %m", filename);
1678 
1679 	while (fgets(fname, PATH_MAX, in) != NULL) {
1680 		if (strends(fname, "\n"))
1681 			fname[strlen(fname)-1] = '\0';
1682 		read_symbols(fname);
1683 	}
1684 
1685 	fclose(in);
1686 }
1687 
1688 #define SZ 500
1689 
1690 /* We first write the generated file into memory using the
1691  * following helper, then compare to the file on disk and
1692  * only update the later if anything changed */
1693 
1694 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1695 						      const char *fmt, ...)
1696 {
1697 	char tmp[SZ];
1698 	int len;
1699 	va_list ap;
1700 
1701 	va_start(ap, fmt);
1702 	len = vsnprintf(tmp, SZ, fmt, ap);
1703 	va_end(ap);
1704 
1705 	if (len < 0) {
1706 		perror("vsnprintf failed");
1707 		exit(1);
1708 	}
1709 	if (len >= SZ)
1710 		fatal("buf_printf output truncated for string %s: %d bytes needed, %d available\n",
1711 		      tmp, len + 1, SZ);
1712 
1713 	buf_write(buf, tmp, len);
1714 }
1715 
1716 void buf_write(struct buffer *buf, const char *s, int len)
1717 {
1718 	if (buf->size - buf->pos < len) {
1719 		buf->size += len + SZ;
1720 		buf->p = xrealloc(buf->p, buf->size);
1721 	}
1722 	strncpy(buf->p + buf->pos, s, len);
1723 	buf->pos += len;
1724 }
1725 
1726 /**
1727  * verify_module_namespace() - does @modname have access to this symbol's @namespace
1728  * @namespace: export symbol namespace
1729  * @modname: module name
1730  *
1731  * If @namespace is prefixed with "module:" to indicate it is a module namespace
1732  * then test if @modname matches any of the comma separated patterns.
1733  *
1734  * The patterns only support tail-glob.
1735  */
1736 static bool verify_module_namespace(const char *namespace, const char *modname)
1737 {
1738 	size_t len, modlen = strlen(modname);
1739 	const char *prefix = "module:";
1740 	const char *sep;
1741 	bool glob;
1742 
1743 	if (!strstarts(namespace, prefix))
1744 		return false;
1745 
1746 	for (namespace += strlen(prefix); *namespace; namespace = sep) {
1747 		sep = strchrnul(namespace, ',');
1748 		len = sep - namespace;
1749 
1750 		glob = false;
1751 		if (sep[-1] == '*') {
1752 			len--;
1753 			glob = true;
1754 		}
1755 
1756 		if (*sep)
1757 			sep++;
1758 
1759 		if (strncmp(namespace, modname, len) == 0 && (glob || len == modlen))
1760 			return true;
1761 	}
1762 
1763 	return false;
1764 }
1765 
1766 static void check_exports(struct module *mod)
1767 {
1768 	struct symbol *s, *exp;
1769 
1770 	list_for_each_entry(s, &mod->unresolved_symbols, list) {
1771 		const char *basename;
1772 		exp = find_symbol(s->name);
1773 		if (!exp) {
1774 			if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1775 				modpost_log(!warn_unresolved,
1776 					    "\"%s\" [%s.ko] undefined!\n",
1777 					    s->name, mod->name);
1778 			continue;
1779 		}
1780 		if (exp->module == mod) {
1781 			error("\"%s\" [%s.ko] was exported without definition\n",
1782 			      s->name, mod->name);
1783 			continue;
1784 		}
1785 
1786 		exp->used = true;
1787 		s->module = exp->module;
1788 		s->crc_valid = exp->crc_valid;
1789 		s->crc = exp->crc;
1790 
1791 		basename = get_basename(mod->name);
1792 
1793 		if (!verify_module_namespace(exp->namespace, basename) &&
1794 		    !contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1795 			modpost_log(!allow_missing_ns_imports,
1796 				    "module %s uses symbol %s from namespace %s, but does not import it.\n",
1797 				    basename, exp->name, exp->namespace);
1798 			add_namespace(&mod->missing_namespaces, exp->namespace);
1799 		}
1800 
1801 		if (!mod->is_gpl_compatible && exp->is_gpl_only)
1802 			error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1803 			      basename, exp->name);
1804 	}
1805 }
1806 
1807 static void handle_white_list_exports(const char *white_list)
1808 {
1809 	char *buf, *p, *name;
1810 
1811 	buf = read_text_file(white_list);
1812 	p = buf;
1813 
1814 	while ((name = strsep(&p, "\n"))) {
1815 		struct symbol *sym = find_symbol(name);
1816 
1817 		if (sym)
1818 			sym->used = true;
1819 	}
1820 
1821 	free(buf);
1822 }
1823 
1824 /*
1825  * Keep symbols recorded in the .no_trim_symbol section. This is necessary to
1826  * prevent CONFIG_TRIM_UNUSED_KSYMS from dropping EXPORT_SYMBOL because
1827  * symbol_get() relies on the symbol being present in the ksymtab for lookups.
1828  */
1829 static void keep_no_trim_symbols(struct module *mod)
1830 {
1831 	unsigned long size = mod->no_trim_symbol_len;
1832 
1833 	for (char *s = mod->no_trim_symbol; s; s = next_string(s , &size)) {
1834 		struct symbol *sym;
1835 
1836 		/*
1837 		 * If find_symbol() returns NULL, this symbol is not provided
1838 		 * by any module, and symbol_get() will fail.
1839 		 */
1840 		sym = find_symbol(s);
1841 		if (sym)
1842 			sym->used = true;
1843 	}
1844 }
1845 
1846 static void check_modname_len(struct module *mod)
1847 {
1848 	const char *mod_name;
1849 
1850 	mod_name = get_basename(mod->name);
1851 
1852 	if (strlen(mod_name) >= MODULE_NAME_LEN)
1853 		error("module name is too long [%s.ko]\n", mod->name);
1854 }
1855 
1856 /**
1857  * Header for the generated file
1858  **/
1859 static void add_header(struct buffer *b, struct module *mod)
1860 {
1861 	buf_printf(b, "#include <linux/module.h>\n");
1862 	buf_printf(b, "#include <linux/export-internal.h>\n");
1863 	buf_printf(b, "#include <linux/compiler.h>\n");
1864 	buf_printf(b, "\n");
1865 	buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1866 	buf_printf(b, "\n");
1867 	buf_printf(b, "__visible struct module __this_module\n");
1868 	buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1869 	buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1870 	if (mod->has_init)
1871 		buf_printf(b, "\t.init = init_module,\n");
1872 	if (mod->has_cleanup)
1873 		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1874 			      "\t.exit = cleanup_module,\n"
1875 			      "#endif\n");
1876 	buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1877 	buf_printf(b, "};\n");
1878 
1879 	if (!external_module)
1880 		buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1881 
1882 	if (strstarts(mod->name, "drivers/staging"))
1883 		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1884 
1885 	if (strstarts(mod->name, "tools/testing"))
1886 		buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1887 }
1888 
1889 static void add_exported_symbols(struct buffer *buf, struct module *mod)
1890 {
1891 	struct symbol *sym;
1892 
1893 	/* generate struct for exported symbols */
1894 	buf_printf(buf, "\n");
1895 	list_for_each_entry(sym, &mod->exported_symbols, list) {
1896 		if (trim_unused_exports && !sym->used)
1897 			continue;
1898 
1899 		buf_printf(buf, "KSYMTAB_%s(%s, \"%s\");\n",
1900 			   sym->is_func ? "FUNC" : "DATA", sym->name,
1901 			   sym->namespace);
1902 
1903 		buf_printf(buf, "SYMBOL_FLAGS(%s, 0x%02x);\n",
1904 			   sym->name, get_symbol_flags(sym));
1905 	}
1906 
1907 	if (!modversions)
1908 		return;
1909 
1910 	/* record CRCs for exported symbols */
1911 	buf_printf(buf, "\n");
1912 	list_for_each_entry(sym, &mod->exported_symbols, list) {
1913 		if (trim_unused_exports && !sym->used)
1914 			continue;
1915 
1916 		if (!sym->crc_valid)
1917 			warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1918 			     "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1919 			     sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1920 			     sym->name);
1921 
1922 		buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x);\n",
1923 			   sym->name, sym->crc);
1924 	}
1925 }
1926 
1927 /**
1928  * Record CRCs for unresolved symbols, supporting long names
1929  */
1930 static void add_extended_versions(struct buffer *b, struct module *mod)
1931 {
1932 	struct symbol *s;
1933 
1934 	if (!extended_modversions)
1935 		return;
1936 
1937 	buf_printf(b, "\n");
1938 	buf_printf(b, "static const u32 ____version_ext_crcs[]\n");
1939 	buf_printf(b, "__used __section(\"__version_ext_crcs\") = {\n");
1940 	list_for_each_entry(s, &mod->unresolved_symbols, list) {
1941 		if (!s->module)
1942 			continue;
1943 		if (!s->crc_valid) {
1944 			warn("\"%s\" [%s.ko] has no CRC!\n",
1945 				s->name, mod->name);
1946 			continue;
1947 		}
1948 		buf_printf(b, "\t0x%08x,\n", s->crc);
1949 	}
1950 	buf_printf(b, "};\n");
1951 
1952 	buf_printf(b, "static const char ____version_ext_names[]\n");
1953 	buf_printf(b, "__used __section(\"__version_ext_names\") =\n");
1954 	list_for_each_entry(s, &mod->unresolved_symbols, list) {
1955 		if (!s->module)
1956 			continue;
1957 		if (!s->crc_valid)
1958 			/*
1959 			 * We already warned on this when producing the crc
1960 			 * table.
1961 			 * We need to skip its name too, as the indexes in
1962 			 * both tables need to align.
1963 			 */
1964 			continue;
1965 		buf_printf(b, "\t\"%s\\0\"\n", s->name);
1966 	}
1967 	buf_printf(b, ";\n");
1968 }
1969 
1970 /**
1971  * Record CRCs for unresolved symbols
1972  **/
1973 static void add_versions(struct buffer *b, struct module *mod)
1974 {
1975 	struct symbol *s;
1976 
1977 	if (!basic_modversions)
1978 		return;
1979 
1980 	buf_printf(b, "\n");
1981 	buf_printf(b, "static const struct modversion_info ____versions[]\n");
1982 	buf_printf(b, "__used __section(\"__versions\") = {\n");
1983 
1984 	list_for_each_entry(s, &mod->unresolved_symbols, list) {
1985 		if (!s->module)
1986 			continue;
1987 		if (!s->crc_valid) {
1988 			warn("\"%s\" [%s.ko] has no CRC!\n",
1989 				s->name, mod->name);
1990 			continue;
1991 		}
1992 		if (strlen(s->name) >= MODULE_NAME_LEN) {
1993 			if (extended_modversions) {
1994 				/* this symbol will only be in the extended info */
1995 				continue;
1996 			} else {
1997 				error("too long symbol \"%s\" [%s.ko]\n",
1998 				      s->name, mod->name);
1999 				break;
2000 			}
2001 		}
2002 		buf_printf(b, "\t{ 0x%08x, \"%s\" },\n",
2003 			   s->crc, s->name);
2004 	}
2005 
2006 	buf_printf(b, "};\n");
2007 }
2008 
2009 static void add_depends(struct buffer *b, struct module *mod)
2010 {
2011 	struct symbol *s;
2012 	int first = 1;
2013 
2014 	/* Clear ->seen flag of modules that own symbols needed by this. */
2015 	list_for_each_entry(s, &mod->unresolved_symbols, list) {
2016 		if (s->module)
2017 			s->module->seen = s->module->is_vmlinux;
2018 	}
2019 
2020 	buf_printf(b, "\n");
2021 	buf_printf(b, "MODULE_INFO(depends, \"");
2022 	list_for_each_entry(s, &mod->unresolved_symbols, list) {
2023 		const char *p;
2024 		if (!s->module)
2025 			continue;
2026 
2027 		if (s->module->seen)
2028 			continue;
2029 
2030 		s->module->seen = true;
2031 		p = get_basename(s->module->name);
2032 		buf_printf(b, "%s%s", first ? "" : ",", p);
2033 		first = 0;
2034 	}
2035 	buf_printf(b, "\");\n");
2036 }
2037 
2038 static void add_srcversion(struct buffer *b, struct module *mod)
2039 {
2040 	if (mod->srcversion[0]) {
2041 		buf_printf(b, "\n");
2042 		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2043 			   mod->srcversion);
2044 	}
2045 }
2046 
2047 static void write_buf(struct buffer *b, const char *fname)
2048 {
2049 	FILE *file;
2050 
2051 	if (error_occurred)
2052 		return;
2053 
2054 	file = fopen(fname, "w");
2055 	if (!file) {
2056 		perror(fname);
2057 		exit(1);
2058 	}
2059 	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2060 		perror(fname);
2061 		exit(1);
2062 	}
2063 	if (fclose(file) != 0) {
2064 		perror(fname);
2065 		exit(1);
2066 	}
2067 }
2068 
2069 static void write_if_changed(struct buffer *b, const char *fname)
2070 {
2071 	char *tmp;
2072 	FILE *file;
2073 	struct stat st;
2074 
2075 	file = fopen(fname, "r");
2076 	if (!file)
2077 		goto write;
2078 
2079 	if (fstat(fileno(file), &st) < 0)
2080 		goto close_write;
2081 
2082 	if (st.st_size != b->pos)
2083 		goto close_write;
2084 
2085 	tmp = xmalloc(b->pos);
2086 	if (fread(tmp, 1, b->pos, file) != b->pos)
2087 		goto free_write;
2088 
2089 	if (memcmp(tmp, b->p, b->pos) != 0)
2090 		goto free_write;
2091 
2092 	free(tmp);
2093 	fclose(file);
2094 	return;
2095 
2096  free_write:
2097 	free(tmp);
2098  close_write:
2099 	fclose(file);
2100  write:
2101 	write_buf(b, fname);
2102 }
2103 
2104 static void write_vmlinux_export_c_file(struct module *mod)
2105 {
2106 	struct buffer buf = { };
2107 	struct module_alias *alias, *next;
2108 
2109 	buf_printf(&buf,
2110 		   "#include <linux/export-internal.h>\n");
2111 
2112 	add_exported_symbols(&buf, mod);
2113 
2114 	buf_printf(&buf,
2115 		   "#include <linux/module.h>\n"
2116 		   "#undef __MODULE_INFO_PREFIX\n"
2117 		   "#define __MODULE_INFO_PREFIX\n");
2118 
2119 	list_for_each_entry_safe(alias, next, &mod->aliases, node) {
2120 		buf_printf(&buf, "MODULE_INFO(%s.alias, \"%s\");\n",
2121 			   alias->builtin_modname, alias->str);
2122 		list_del(&alias->node);
2123 		free(alias->builtin_modname);
2124 		free(alias);
2125 	}
2126 
2127 	write_if_changed(&buf, ".vmlinux.export.c");
2128 	free(buf.p);
2129 }
2130 
2131 /* do sanity checks, and generate *.mod.c file */
2132 static void write_mod_c_file(struct module *mod)
2133 {
2134 	struct buffer buf = { };
2135 	struct module_alias *alias, *next;
2136 	char fname[PATH_MAX];
2137 	int ret;
2138 
2139 	add_header(&buf, mod);
2140 	add_exported_symbols(&buf, mod);
2141 	add_versions(&buf, mod);
2142 	add_extended_versions(&buf, mod);
2143 	add_depends(&buf, mod);
2144 
2145 	buf_printf(&buf, "\n");
2146 	list_for_each_entry_safe(alias, next, &mod->aliases, node) {
2147 		buf_printf(&buf, "MODULE_ALIAS(\"%s\");\n", alias->str);
2148 		list_del(&alias->node);
2149 		free(alias);
2150 	}
2151 
2152 	add_srcversion(&buf, mod);
2153 
2154 	ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
2155 	if (ret >= sizeof(fname)) {
2156 		error("%s: too long path was truncated\n", fname);
2157 		goto free;
2158 	}
2159 
2160 	write_if_changed(&buf, fname);
2161 
2162 free:
2163 	free(buf.p);
2164 }
2165 
2166 /* parse Module.symvers file. line format:
2167  * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2168  **/
2169 static void read_dump(const char *fname)
2170 {
2171 	char *buf, *pos, *line;
2172 
2173 	buf = read_text_file(fname);
2174 	if (!buf)
2175 		/* No symbol versions, silently ignore */
2176 		return;
2177 
2178 	pos = buf;
2179 
2180 	while ((line = get_line(&pos))) {
2181 		char *symname, *namespace, *modname, *d, *export;
2182 		unsigned int crc;
2183 		struct module *mod;
2184 		struct symbol *s;
2185 		bool gpl_only;
2186 
2187 		if (!(symname = strchr(line, '\t')))
2188 			goto fail;
2189 		*symname++ = '\0';
2190 		if (!(modname = strchr(symname, '\t')))
2191 			goto fail;
2192 		*modname++ = '\0';
2193 		if (!(export = strchr(modname, '\t')))
2194 			goto fail;
2195 		*export++ = '\0';
2196 		if (!(namespace = strchr(export, '\t')))
2197 			goto fail;
2198 		*namespace++ = '\0';
2199 
2200 		crc = strtoul(line, &d, 16);
2201 		if (*symname == '\0' || *modname == '\0' || *d != '\0')
2202 			goto fail;
2203 
2204 		if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2205 			gpl_only = true;
2206 		} else if (!strcmp(export, "EXPORT_SYMBOL")) {
2207 			gpl_only = false;
2208 		} else {
2209 			error("%s: unknown license %s. skip", symname, export);
2210 			continue;
2211 		}
2212 
2213 		mod = find_module(fname, modname);
2214 		if (!mod) {
2215 			mod = new_module(modname, strlen(modname));
2216 			mod->dump_file = fname;
2217 		}
2218 		s = sym_add_exported(symname, mod, gpl_only, namespace);
2219 		sym_set_crc(s, crc);
2220 	}
2221 	free(buf);
2222 	return;
2223 fail:
2224 	free(buf);
2225 	fatal("parse error in symbol dump file\n");
2226 }
2227 
2228 static void write_dump(const char *fname)
2229 {
2230 	struct buffer buf = { };
2231 	struct module *mod;
2232 	struct symbol *sym;
2233 
2234 	list_for_each_entry(mod, &modules, list) {
2235 		if (mod->dump_file)
2236 			continue;
2237 		list_for_each_entry(sym, &mod->exported_symbols, list) {
2238 			if (trim_unused_exports && !sym->used)
2239 				continue;
2240 
2241 			buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2242 				   sym->crc, sym->name, mod->name,
2243 				   sym->is_gpl_only ? "_GPL" : "",
2244 				   sym->namespace);
2245 		}
2246 	}
2247 	write_buf(&buf, fname);
2248 	free(buf.p);
2249 }
2250 
2251 static void write_namespace_deps_files(const char *fname)
2252 {
2253 	struct module *mod;
2254 	struct namespace_list *ns;
2255 	struct buffer ns_deps_buf = {};
2256 
2257 	list_for_each_entry(mod, &modules, list) {
2258 
2259 		if (mod->dump_file || list_empty(&mod->missing_namespaces))
2260 			continue;
2261 
2262 		buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2263 
2264 		list_for_each_entry(ns, &mod->missing_namespaces, list)
2265 			buf_printf(&ns_deps_buf, " %s", ns->namespace);
2266 
2267 		buf_printf(&ns_deps_buf, "\n");
2268 	}
2269 
2270 	write_if_changed(&ns_deps_buf, fname);
2271 	free(ns_deps_buf.p);
2272 }
2273 
2274 struct dump_list {
2275 	struct list_head list;
2276 	const char *file;
2277 };
2278 
2279 static void check_host_endian(void)
2280 {
2281 	static const union {
2282 		short s;
2283 		char c[2];
2284 	} endian_test = { .c = {0x01, 0x02} };
2285 
2286 	switch (endian_test.s) {
2287 	case 0x0102:
2288 		host_is_big_endian = true;
2289 		break;
2290 	case 0x0201:
2291 		host_is_big_endian = false;
2292 		break;
2293 	default:
2294 		fatal("Unknown host endian\n");
2295 	}
2296 }
2297 
2298 int main(int argc, char **argv)
2299 {
2300 	struct module *mod;
2301 	char *missing_namespace_deps = NULL;
2302 	char *unused_exports_white_list = NULL;
2303 	char *dump_write = NULL, *files_source = NULL;
2304 	int opt;
2305 	LIST_HEAD(dump_lists);
2306 	struct dump_list *dl, *dl2;
2307 
2308 	while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:xb")) != -1) {
2309 		switch (opt) {
2310 		case 'e':
2311 			external_module = true;
2312 			break;
2313 		case 'i':
2314 			dl = xmalloc(sizeof(*dl));
2315 			dl->file = optarg;
2316 			list_add_tail(&dl->list, &dump_lists);
2317 			break;
2318 		case 'M':
2319 			module_enabled = true;
2320 			break;
2321 		case 'm':
2322 			modversions = true;
2323 			break;
2324 		case 'n':
2325 			ignore_missing_files = true;
2326 			break;
2327 		case 'o':
2328 			dump_write = optarg;
2329 			break;
2330 		case 'a':
2331 			all_versions = true;
2332 			break;
2333 		case 'T':
2334 			files_source = optarg;
2335 			break;
2336 		case 't':
2337 			trim_unused_exports = true;
2338 			break;
2339 		case 'u':
2340 			unused_exports_white_list = optarg;
2341 			break;
2342 		case 'W':
2343 			extra_warn = true;
2344 			break;
2345 		case 'w':
2346 			warn_unresolved = true;
2347 			break;
2348 		case 'E':
2349 			sec_mismatch_warn_only = false;
2350 			break;
2351 		case 'N':
2352 			allow_missing_ns_imports = true;
2353 			break;
2354 		case 'd':
2355 			missing_namespace_deps = optarg;
2356 			break;
2357 		case 'b':
2358 			basic_modversions = true;
2359 			break;
2360 		case 'x':
2361 			extended_modversions = true;
2362 			break;
2363 		default:
2364 			exit(1);
2365 		}
2366 	}
2367 
2368 	check_host_endian();
2369 
2370 	list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2371 		read_dump(dl->file);
2372 		list_del(&dl->list);
2373 		free(dl);
2374 	}
2375 
2376 	while (optind < argc)
2377 		read_symbols(argv[optind++]);
2378 
2379 	if (files_source)
2380 		read_symbols_from_files(files_source);
2381 
2382 	list_for_each_entry(mod, &modules, list) {
2383 		keep_no_trim_symbols(mod);
2384 
2385 		if (mod->dump_file || mod->is_vmlinux)
2386 			continue;
2387 
2388 		check_modname_len(mod);
2389 		check_exports(mod);
2390 	}
2391 
2392 	if (unused_exports_white_list)
2393 		handle_white_list_exports(unused_exports_white_list);
2394 
2395 	list_for_each_entry(mod, &modules, list) {
2396 		if (mod->dump_file)
2397 			continue;
2398 
2399 		if (mod->is_vmlinux)
2400 			write_vmlinux_export_c_file(mod);
2401 		else
2402 			write_mod_c_file(mod);
2403 	}
2404 
2405 	if (missing_namespace_deps)
2406 		write_namespace_deps_files(missing_namespace_deps);
2407 
2408 	if (dump_write)
2409 		write_dump(dump_write);
2410 	if (sec_mismatch_count && !sec_mismatch_warn_only)
2411 		error("Section mismatches detected.\n"
2412 		      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2413 
2414 	if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2415 		warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2416 		     nr_unresolved - MAX_UNRESOLVED_REPORTS);
2417 
2418 	return error_occurred ? 1 : 0;
2419 }
2420