1/* Postprocess module symbol versions
   2 *
   3 * Copyright 2003       Kai Germaschewski
   4 * Copyright 2002-2004  Rusty Russell, IBM Corporation
   5 * Copyright 2006-2008  Sam Ravnborg
   6 * Based in part on module-init-tools/depmod.c,file2alias
   7 *
   8 * This software may be used and distributed according to the terms
   9 * of the GNU General Public License, incorporated herein by reference.
  10 *
  11 * Usage: modpost vmlinux module1.o module2.o ...
  12 */
  13
  14#define _GNU_SOURCE
  15#include <stdio.h>
  16#include <ctype.h>
  17#include <string.h>
  18#include "modpost.h"
  19#include "../../include/generated/autoconf.h"
  20#include "../../include/linux/license.h"
  21
  22/* Some toolchains use a `_' prefix for all user symbols. */
  23#ifdef CONFIG_SYMBOL_PREFIX
  24#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
  25#else
  26#define MODULE_SYMBOL_PREFIX ""
  27#endif
  28
  29
  30/* Are we using CONFIG_MODVERSIONS? */
  31int modversions = 0;
  32/* Warn about undefined symbols? (do so if we have vmlinux) */
  33int have_vmlinux = 0;
  34/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  35static int all_versions = 0;
  36/* If we are modposting external module set to 1 */
  37static int external_module = 0;
  38/* Warn about section mismatch in vmlinux if set to 1 */
  39static int vmlinux_section_warnings = 1;
  40/* Only warn about unresolved symbols */
  41static int warn_unresolved = 0;
  42/* How a symbol is exported */
  43static int sec_mismatch_count = 0;
  44static int sec_mismatch_verbose = 1;
  45
  46enum export {
  47	export_plain,      export_unused,     export_gpl,
  48	export_unused_gpl, export_gpl_future, export_unknown
  49};
  50
  51#define PRINTF __attribute__ ((format (printf, 1, 2)))
  52
  53PRINTF void fatal(const char *fmt, ...)
  54{
  55	va_list arglist;
  56
  57	fprintf(stderr, "FATAL: ");
  58
  59	va_start(arglist, fmt);
  60	vfprintf(stderr, fmt, arglist);
  61	va_end(arglist);
  62
  63	exit(1);
  64}
  65
  66PRINTF void warn(const char *fmt, ...)
  67{
  68	va_list arglist;
  69
  70	fprintf(stderr, "WARNING: ");
  71
  72	va_start(arglist, fmt);
  73	vfprintf(stderr, fmt, arglist);
  74	va_end(arglist);
  75}
  76
  77PRINTF void merror(const char *fmt, ...)
  78{
  79	va_list arglist;
  80
  81	fprintf(stderr, "ERROR: ");
  82
  83	va_start(arglist, fmt);
  84	vfprintf(stderr, fmt, arglist);
  85	va_end(arglist);
  86}
  87
  88static int is_vmlinux(const char *modname)
  89{
  90	const char *myname;
  91
  92	myname = strrchr(modname, '/');
  93	if (myname)
  94		myname++;
  95	else
  96		myname = modname;
  97
  98	return (strcmp(myname, "vmlinux") == 0) ||
  99	       (strcmp(myname, "vmlinux.o") == 0);
 100}
 101
 102void *do_nofail(void *ptr, const char *expr)
 103{
 104	if (!ptr)
 105		fatal("modpost: Memory allocation failure: %s.\n", expr);
 106
 107	return ptr;
 108}
 109
 110/* A list of all modules we processed */
 111static struct module *modules;
 112
 113static struct module *find_module(char *modname)
 114{
 115	struct module *mod;
 116
 117	for (mod = modules; mod; mod = mod->next)
 118		if (strcmp(mod->name, modname) == 0)
 119			break;
 120	return mod;
 121}
 122
 123static struct module *new_module(char *modname)
 124{
 125	struct module *mod;
 126	char *p, *s;
 127
 128	mod = NOFAIL(malloc(sizeof(*mod)));
 129	memset(mod, 0, sizeof(*mod));
 130	p = NOFAIL(strdup(modname));
 131
 132	/* strip trailing .o */
 133	s = strrchr(p, '.');
 134	if (s != NULL)
 135		if (strcmp(s, ".o") == 0) {
 136			*s = '\0';
 137			mod->is_dot_o = 1;
 138		}
 139
 140	/* add to list */
 141	mod->name = p;
 142	mod->gpl_compatible = -1;
 143	mod->next = modules;
 144	modules = mod;
 145
 146	return mod;
 147}
 148
 149/* A hash of all exported symbols,
 150 * struct symbol is also used for lists of unresolved symbols */
 151
 152#define SYMBOL_HASH_SIZE 1024
 153
 154struct symbol {
 155	struct symbol *next;
 156	struct module *module;
 157	unsigned int crc;
 158	int crc_valid;
 159	unsigned int weak:1;
 160	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 161	unsigned int kernel:1;     /* 1 if symbol is from kernel
 162				    *  (only for external modules) **/
 163	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
 164	enum export  export;       /* Type of export */
 165	char name[0];
 166};
 167
 168static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 169
 170/* This is based on the hash agorithm from gdbm, via tdb */
 171static inline unsigned int tdb_hash(const char *name)
 172{
 173	unsigned value;	/* Used to compute the hash value.  */
 174	unsigned   i;	/* Used to cycle through random values. */
 175
 176	/* Set the initial value from the key size. */
 177	for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 178		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 179
 180	return (1103515243 * value + 12345);
 181}
 182
 183/**
 184 * Allocate a new symbols for use in the hash of exported symbols or
 185 * the list of unresolved symbols per module
 186 **/
 187static struct symbol *alloc_symbol(const char *name, unsigned int weak,
 188				   struct symbol *next)
 189{
 190	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 191
 192	memset(s, 0, sizeof(*s));
 193	strcpy(s->name, name);
 194	s->weak = weak;
 195	s->next = next;
 196	return s;
 197}
 198
 199/* For the hash of exported symbols */
 200static struct symbol *new_symbol(const char *name, struct module *module,
 201				 enum export export)
 202{
 203	unsigned int hash;
 204	struct symbol *new;
 205
 206	hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
 207	new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
 208	new->module = module;
 209	new->export = export;
 210	return new;
 211}
 212
 213static struct symbol *find_symbol(const char *name)
 214{
 215	struct symbol *s;
 216
 217	/* For our purposes, .foo matches foo.  PPC64 needs this. */
 218	if (name[0] == '.')
 219		name++;
 220
 221	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 222		if (strcmp(s->name, name) == 0)
 223			return s;
 224	}
 225	return NULL;
 226}
 227
 228static struct {
 229	const char *str;
 230	enum export export;
 231} export_list[] = {
 232	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
 233	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 234	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 235	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 236	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 237	{ .str = "(unknown)",                .export = export_unknown },
 238};
 239
 240
 241static const char *export_str(enum export ex)
 242{
 243	return export_list[ex].str;
 244}
 245
 246static enum export export_no(const char *s)
 247{
 248	int i;
 249
 250	if (!s)
 251		return export_unknown;
 252	for (i = 0; export_list[i].export != export_unknown; i++) {
 253		if (strcmp(export_list[i].str, s) == 0)
 254			return export_list[i].export;
 255	}
 256	return export_unknown;
 257}
 258
 259static const char *sec_name(struct elf_info *elf, int secindex);
 260
 261#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 262
 263static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 264{
 265	const char *secname = sec_name(elf, sec);
 266
 267	if (strstarts(secname, "___ksymtab+"))
 268		return export_plain;
 269	else if (strstarts(secname, "___ksymtab_unused+"))
 270		return export_unused;
 271	else if (strstarts(secname, "___ksymtab_gpl+"))
 272		return export_gpl;
 273	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
 274		return export_unused_gpl;
 275	else if (strstarts(secname, "___ksymtab_gpl_future+"))
 276		return export_gpl_future;
 277	else
 278		return export_unknown;
 279}
 280
 281static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 282{
 283	if (sec == elf->export_sec)
 284		return export_plain;
 285	else if (sec == elf->export_unused_sec)
 286		return export_unused;
 287	else if (sec == elf->export_gpl_sec)
 288		return export_gpl;
 289	else if (sec == elf->export_unused_gpl_sec)
 290		return export_unused_gpl;
 291	else if (sec == elf->export_gpl_future_sec)
 292		return export_gpl_future;
 293	else
 294		return export_unknown;
 295}
 296
 297/**
 298 * Add an exported symbol - it may have already been added without a
 299 * CRC, in this case just update the CRC
 300 **/
 301static struct symbol *sym_add_exported(const char *name, struct module *mod,
 302				       enum export export)
 303{
 304	struct symbol *s = find_symbol(name);
 305
 306	if (!s) {
 307		s = new_symbol(name, mod, export);
 308	} else {
 309		if (!s->preloaded) {
 310			warn("%s: '%s' exported twice. Previous export "
 311			     "was in %s%s\n", mod->name, name,
 312			     s->module->name,
 313			     is_vmlinux(s->module->name) ?"":".ko");
 314		} else {
 315			/* In case Modules.symvers was out of date */
 316			s->module = mod;
 317		}
 318	}
 319	s->preloaded = 0;
 320	s->vmlinux   = is_vmlinux(mod->name);
 321	s->kernel    = 0;
 322	s->export    = export;
 323	return s;
 324}
 325
 326static void sym_update_crc(const char *name, struct module *mod,
 327			   unsigned int crc, enum export export)
 328{
 329	struct symbol *s = find_symbol(name);
 330
 331	if (!s)
 332		s = new_symbol(name, mod, export);
 333	s->crc = crc;
 334	s->crc_valid = 1;
 335}
 336
 337void *grab_file(const char *filename, unsigned long *size)
 338{
 339	struct stat st;
 340	void *map = MAP_FAILED;
 341	int fd;
 342
 343	fd = open(filename, O_RDONLY);
 344	if (fd < 0)
 345		return NULL;
 346	if (fstat(fd, &st))
 347		goto failed;
 348
 349	*size = st.st_size;
 350	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 351
 352failed:
 353	close(fd);
 
 354	if (map == MAP_FAILED)
 355		return NULL;
 356	return map;
 357}
 358
 359/**
 360  * Return a copy of the next line in a mmap'ed file.
 361  * spaces in the beginning of the line is trimmed away.
 362  * Return a pointer to a static buffer.
 363  **/
 364char *get_next_line(unsigned long *pos, void *file, unsigned long size)
 365{
 366	static char line[4096];
 367	int skip = 1;
 368	size_t len = 0;
 369	signed char *p = (signed char *)file + *pos;
 370	char *s = line;
 371
 372	for (; *pos < size ; (*pos)++) {
 373		if (skip && isspace(*p)) {
 374			p++;
 375			continue;
 376		}
 377		skip = 0;
 378		if (*p != '\n' && (*pos < size)) {
 379			len++;
 380			*s++ = *p++;
 381			if (len > 4095)
 382				break; /* Too long, stop */
 383		} else {
 384			/* End of string */
 385			*s = '\0';
 386			return line;
 387		}
 388	}
 389	/* End of buffer */
 390	return NULL;
 391}
 392
 393void release_file(void *file, unsigned long size)
 394{
 395	munmap(file, size);
 396}
 397
 398static int parse_elf(struct elf_info *info, const char *filename)
 399{
 400	unsigned int i;
 401	Elf_Ehdr *hdr;
 402	Elf_Shdr *sechdrs;
 403	Elf_Sym  *sym;
 404	const char *secstrings;
 405	unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 406
 407	hdr = grab_file(filename, &info->size);
 408	if (!hdr) {
 409		perror(filename);
 410		exit(1);
 411	}
 412	info->hdr = hdr;
 413	if (info->size < sizeof(*hdr)) {
 414		/* file too small, assume this is an empty .o file */
 415		return 0;
 416	}
 417	/* Is this a valid ELF file? */
 418	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 419	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 420	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 421	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 422		/* Not an ELF file - silently ignore it */
 423		return 0;
 424	}
 425	/* Fix endianness in ELF header */
 426	hdr->e_type      = TO_NATIVE(hdr->e_type);
 427	hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 428	hdr->e_version   = TO_NATIVE(hdr->e_version);
 429	hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 430	hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 431	hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 432	hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 433	hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 434	hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 435	hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 436	hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 437	hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 438	hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 439	sechdrs = (void *)hdr + hdr->e_shoff;
 440	info->sechdrs = sechdrs;
 441
 442	/* Check if file offset is correct */
 443	if (hdr->e_shoff > info->size) {
 444		fatal("section header offset=%lu in file '%s' is bigger than "
 445		      "filesize=%lu\n", (unsigned long)hdr->e_shoff,
 446		      filename, info->size);
 447		return 0;
 448	}
 449
 450	if (hdr->e_shnum == SHN_UNDEF) {
 451		/*
 452		 * There are more than 64k sections,
 453		 * read count from .sh_size.
 454		 */
 455		info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 456	}
 457	else {
 458		info->num_sections = hdr->e_shnum;
 459	}
 460	if (hdr->e_shstrndx == SHN_XINDEX) {
 461		info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
 462	}
 463	else {
 464		info->secindex_strings = hdr->e_shstrndx;
 465	}
 466
 467	/* Fix endianness in section headers */
 468	for (i = 0; i < info->num_sections; i++) {
 469		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 470		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 471		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 472		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 473		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 474		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 475		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 476		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 477		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 478		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 479	}
 480	/* Find symbol table. */
 481	secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 482	for (i = 1; i < info->num_sections; i++) {
 483		const char *secname;
 484		int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 485
 486		if (!nobits && sechdrs[i].sh_offset > info->size) {
 487			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
 488			      "sizeof(*hrd)=%zu\n", filename,
 489			      (unsigned long)sechdrs[i].sh_offset,
 490			      sizeof(*hdr));
 491			return 0;
 492		}
 493		secname = secstrings + sechdrs[i].sh_name;
 494		if (strcmp(secname, ".modinfo") == 0) {
 495			if (nobits)
 496				fatal("%s has NOBITS .modinfo\n", filename);
 497			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 498			info->modinfo_len = sechdrs[i].sh_size;
 499		} else if (strcmp(secname, "__ksymtab") == 0)
 500			info->export_sec = i;
 501		else if (strcmp(secname, "__ksymtab_unused") == 0)
 502			info->export_unused_sec = i;
 503		else if (strcmp(secname, "__ksymtab_gpl") == 0)
 504			info->export_gpl_sec = i;
 505		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 506			info->export_unused_gpl_sec = i;
 507		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
 508			info->export_gpl_future_sec = i;
 509
 510		if (sechdrs[i].sh_type == SHT_SYMTAB) {
 511			unsigned int sh_link_idx;
 512			symtab_idx = i;
 513			info->symtab_start = (void *)hdr +
 514			    sechdrs[i].sh_offset;
 515			info->symtab_stop  = (void *)hdr +
 516			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
 517			sh_link_idx = sechdrs[i].sh_link;
 518			info->strtab       = (void *)hdr +
 519			    sechdrs[sh_link_idx].sh_offset;
 520		}
 521
 522		/* 32bit section no. table? ("more than 64k sections") */
 523		if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 524			symtab_shndx_idx = i;
 525			info->symtab_shndx_start = (void *)hdr +
 526			    sechdrs[i].sh_offset;
 527			info->symtab_shndx_stop  = (void *)hdr +
 528			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
 529		}
 530	}
 531	if (!info->symtab_start)
 532		fatal("%s has no symtab?\n", filename);
 533
 534	/* Fix endianness in symbols */
 535	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 536		sym->st_shndx = TO_NATIVE(sym->st_shndx);
 537		sym->st_name  = TO_NATIVE(sym->st_name);
 538		sym->st_value = TO_NATIVE(sym->st_value);
 539		sym->st_size  = TO_NATIVE(sym->st_size);
 540	}
 541
 542	if (symtab_shndx_idx != ~0U) {
 543		Elf32_Word *p;
 544		if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
 545			fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 546			      filename, sechdrs[symtab_shndx_idx].sh_link,
 547			      symtab_idx);
 548		/* Fix endianness */
 549		for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 550		     p++)
 551			*p = TO_NATIVE(*p);
 552	}
 553
 554	return 1;
 555}
 556
 557static void parse_elf_finish(struct elf_info *info)
 558{
 559	release_file(info->hdr, info->size);
 560}
 561
 562static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 563{
 564	/* ignore __this_module, it will be resolved shortly */
 565	if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
 566		return 1;
 567	/* ignore global offset table */
 568	if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 569		return 1;
 570	if (info->hdr->e_machine == EM_PPC)
 571		/* Special register function linked on all modules during final link of .ko */
 572		if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
 573		    strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
 574		    strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
 575		    strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
 576			return 1;
 577	if (info->hdr->e_machine == EM_PPC64)
 578		/* Special register function linked on all modules during final link of .ko */
 579		if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
 580		    strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
 581			return 1;
 582	/* Do not ignore this symbol */
 583	return 0;
 584}
 585
 586#define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
 587#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
 588
 589static void handle_modversions(struct module *mod, struct elf_info *info,
 590			       Elf_Sym *sym, const char *symname)
 591{
 592	unsigned int crc;
 593	enum export export;
 594
 595	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
 596	    strncmp(symname, "__ksymtab", 9) == 0)
 597		export = export_from_secname(info, get_secindex(info, sym));
 598	else
 599		export = export_from_sec(info, get_secindex(info, sym));
 600
 601	switch (sym->st_shndx) {
 602	case SHN_COMMON:
 603		warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 604		break;
 605	case SHN_ABS:
 606		/* CRC'd symbol */
 607		if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
 608			crc = (unsigned int) sym->st_value;
 609			sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
 610					export);
 611		}
 612		break;
 613	case SHN_UNDEF:
 614		/* undefined symbol */
 615		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 616		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
 617			break;
 618		if (ignore_undef_symbol(info, symname))
 619			break;
 620/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
 621#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
 622/* add compatibility with older glibc */
 623#ifndef STT_SPARC_REGISTER
 624#define STT_SPARC_REGISTER STT_REGISTER
 625#endif
 626		if (info->hdr->e_machine == EM_SPARC ||
 627		    info->hdr->e_machine == EM_SPARCV9) {
 628			/* Ignore register directives. */
 629			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 630				break;
 631			if (symname[0] == '.') {
 632				char *munged = strdup(symname);
 633				munged[0] = '_';
 634				munged[1] = toupper(munged[1]);
 635				symname = munged;
 636			}
 637		}
 638#endif
 639
 640		if (memcmp(symname, MODULE_SYMBOL_PREFIX,
 641			   strlen(MODULE_SYMBOL_PREFIX)) == 0) {
 642			mod->unres =
 643			  alloc_symbol(symname +
 644			               strlen(MODULE_SYMBOL_PREFIX),
 645			               ELF_ST_BIND(sym->st_info) == STB_WEAK,
 646			               mod->unres);
 647		}
 648		break;
 649	default:
 650		/* All exported symbols */
 651		if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
 652			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
 653					export);
 654		}
 655		if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
 656			mod->has_init = 1;
 657		if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
 658			mod->has_cleanup = 1;
 659		break;
 660	}
 661}
 662
 663/**
 664 * Parse tag=value strings from .modinfo section
 665 **/
 666static char *next_string(char *string, unsigned long *secsize)
 667{
 668	/* Skip non-zero chars */
 669	while (string[0]) {
 670		string++;
 671		if ((*secsize)-- <= 1)
 672			return NULL;
 673	}
 674
 675	/* Skip any zero padding. */
 676	while (!string[0]) {
 677		string++;
 678		if ((*secsize)-- <= 1)
 679			return NULL;
 680	}
 681	return string;
 682}
 683
 684static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
 685			      const char *tag, char *info)
 686{
 687	char *p;
 688	unsigned int taglen = strlen(tag);
 689	unsigned long size = modinfo_len;
 690
 691	if (info) {
 692		size -= info - (char *)modinfo;
 693		modinfo = next_string(info, &size);
 694	}
 695
 696	for (p = modinfo; p; p = next_string(p, &size)) {
 697		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 698			return p + taglen + 1;
 699	}
 700	return NULL;
 701}
 702
 703static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
 704			 const char *tag)
 705
 706{
 707	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
 708}
 709
 710/**
 711 * Test if string s ends in string sub
 712 * return 0 if match
 713 **/
 714static int strrcmp(const char *s, const char *sub)
 715{
 716	int slen, sublen;
 717
 718	if (!s || !sub)
 719		return 1;
 720
 721	slen = strlen(s);
 722	sublen = strlen(sub);
 723
 724	if ((slen == 0) || (sublen == 0))
 725		return 1;
 726
 727	if (sublen > slen)
 728		return 1;
 729
 730	return memcmp(s + slen - sublen, sub, sublen);
 731}
 732
 733static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 734{
 735	if (sym)
 736		return elf->strtab + sym->st_name;
 737	else
 738		return "(unknown)";
 739}
 740
 741static const char *sec_name(struct elf_info *elf, int secindex)
 742{
 743	Elf_Shdr *sechdrs = elf->sechdrs;
 744	return (void *)elf->hdr +
 745		elf->sechdrs[elf->secindex_strings].sh_offset +
 746		sechdrs[secindex].sh_name;
 747}
 748
 749static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
 750{
 751	return (void *)elf->hdr +
 752		elf->sechdrs[elf->secindex_strings].sh_offset +
 753		sechdr->sh_name;
 754}
 755
 756/* if sym is empty or point to a string
 757 * like ".[0-9]+" then return 1.
 758 * This is the optional prefix added by ld to some sections
 759 */
 760static int number_prefix(const char *sym)
 761{
 762	if (*sym++ == '\0')
 763		return 1;
 764	if (*sym != '.')
 765		return 0;
 766	do {
 767		char c = *sym++;
 768		if (c < '0' || c > '9')
 769			return 0;
 770	} while (*sym);
 771	return 1;
 772}
 773
 774/* The pattern is an array of simple patterns.
 775 * "foo" will match an exact string equal to "foo"
 776 * "*foo" will match a string that ends with "foo"
 777 * "foo*" will match a string that begins with "foo"
 778 * "foo$" will match a string equal to "foo" or "foo.1"
 779 *   where the '1' can be any number including several digits.
 780 *   The $ syntax is for sections where ld append a dot number
 781 *   to make section name unique.
 782 */
 783static int match(const char *sym, const char * const pat[])
 784{
 785	const char *p;
 786	while (*pat) {
 787		p = *pat++;
 788		const char *endp = p + strlen(p) - 1;
 789
 790		/* "*foo" */
 791		if (*p == '*') {
 792			if (strrcmp(sym, p + 1) == 0)
 793				return 1;
 794		}
 795		/* "foo*" */
 796		else if (*endp == '*') {
 797			if (strncmp(sym, p, strlen(p) - 1) == 0)
 798				return 1;
 799		}
 800		/* "foo$" */
 801		else if (*endp == '$') {
 802			if (strncmp(sym, p, strlen(p) - 1) == 0) {
 803				if (number_prefix(sym + strlen(p) - 1))
 804					return 1;
 805			}
 806		}
 807		/* no wildcards */
 808		else {
 809			if (strcmp(p, sym) == 0)
 810				return 1;
 811		}
 812	}
 813	/* no match */
 814	return 0;
 815}
 816
 817/* sections that we do not want to do full section mismatch check on */
 818static const char *section_white_list[] =
 819{
 820	".comment*",
 821	".debug*",
 822	".zdebug*",		/* Compressed debug sections. */
 823	".GCC-command-line",	/* mn10300 */
 824	".mdebug*",        /* alpha, score, mips etc. */
 825	".pdr",            /* alpha, score, mips etc. */
 826	".stab*",
 827	".note*",
 828	".got*",
 829	".toc*",
 830	NULL
 831};
 832
 833/*
 834 * This is used to find sections missing the SHF_ALLOC flag.
 835 * The cause of this is often a section specified in assembler
 836 * without "ax" / "aw".
 837 */
 838static void check_section(const char *modname, struct elf_info *elf,
 839                          Elf_Shdr *sechdr)
 840{
 841	const char *sec = sech_name(elf, sechdr);
 842
 843	if (sechdr->sh_type == SHT_PROGBITS &&
 844	    !(sechdr->sh_flags & SHF_ALLOC) &&
 845	    !match(sec, section_white_list)) {
 846		warn("%s (%s): unexpected non-allocatable section.\n"
 847		     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 848		     "Note that for example <linux/init.h> contains\n"
 849		     "section definitions for use in .S files.\n\n",
 850		     modname, sec);
 851	}
 852}
 853
 854
 855
 856#define ALL_INIT_DATA_SECTIONS \
 857	".init.setup$", ".init.rodata$", \
 858	".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$", \
 859	".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
 860#define ALL_EXIT_DATA_SECTIONS \
 861	".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
 862
 863#define ALL_INIT_TEXT_SECTIONS \
 864	".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
 865#define ALL_EXIT_TEXT_SECTIONS \
 866	".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
 867
 868#define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
 869	MEM_INIT_SECTIONS
 870#define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
 871	MEM_EXIT_SECTIONS
 872
 873#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 874#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 875
 876#define DATA_SECTIONS ".data$", ".data.rel$"
 877#define TEXT_SECTIONS ".text$"
 878
 879#define INIT_SECTIONS      ".init.*"
 880#define DEV_INIT_SECTIONS  ".devinit.*"
 881#define CPU_INIT_SECTIONS  ".cpuinit.*"
 882#define MEM_INIT_SECTIONS  ".meminit.*"
 883
 884#define EXIT_SECTIONS      ".exit.*"
 885#define DEV_EXIT_SECTIONS  ".devexit.*"
 886#define CPU_EXIT_SECTIONS  ".cpuexit.*"
 887#define MEM_EXIT_SECTIONS  ".memexit.*"
 888
 889/* init data sections */
 890static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
 891
 892/* all init sections */
 893static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
 894
 895/* All init and exit sections (code + data) */
 896static const char *init_exit_sections[] =
 897	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 898
 899/* data section */
 900static const char *data_sections[] = { DATA_SECTIONS, NULL };
 901
 902
 903/* symbols in .data that may refer to init/exit sections */
 904#define DEFAULT_SYMBOL_WHITE_LIST					\
 905	"*driver",							\
 906	"*_template", /* scsi uses *_template a lot */			\
 907	"*_timer",    /* arm uses ops structures named _timer a lot */	\
 908	"*_sht",      /* scsi also used *_sht to some extent */		\
 909	"*_ops",							\
 910	"*_probe",							\
 911	"*_probe_one",							\
 912	"*_console"
 913
 914static const char *head_sections[] = { ".head.text*", NULL };
 915static const char *linker_symbols[] =
 916	{ "__init_begin", "_sinittext", "_einittext", NULL };
 917
 918enum mismatch {
 919	TEXT_TO_ANY_INIT,
 920	DATA_TO_ANY_INIT,
 921	TEXT_TO_ANY_EXIT,
 922	DATA_TO_ANY_EXIT,
 923	XXXINIT_TO_SOME_INIT,
 924	XXXEXIT_TO_SOME_EXIT,
 925	ANY_INIT_TO_ANY_EXIT,
 926	ANY_EXIT_TO_ANY_INIT,
 927	EXPORT_TO_INIT_EXIT,
 928};
 929
 930struct sectioncheck {
 931	const char *fromsec[20];
 932	const char *tosec[20];
 933	enum mismatch mismatch;
 934	const char *symbol_white_list[20];
 935};
 936
 937const struct sectioncheck sectioncheck[] = {
 938/* Do not reference init/exit code/data from
 939 * normal code and data
 940 */
 941{
 942	.fromsec = { TEXT_SECTIONS, NULL },
 943	.tosec   = { ALL_INIT_SECTIONS, NULL },
 944	.mismatch = TEXT_TO_ANY_INIT,
 945	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 946},
 947{
 948	.fromsec = { DATA_SECTIONS, NULL },
 949	.tosec   = { ALL_XXXINIT_SECTIONS, NULL },
 950	.mismatch = DATA_TO_ANY_INIT,
 951	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 952},
 953{
 954	.fromsec = { DATA_SECTIONS, NULL },
 955	.tosec   = { INIT_SECTIONS, NULL },
 956	.mismatch = DATA_TO_ANY_INIT,
 957	.symbol_white_list = {
 958		"*_template", "*_timer", "*_sht", "*_ops",
 959		"*_probe", "*_probe_one", "*_console", NULL
 960	},
 961},
 962{
 963	.fromsec = { TEXT_SECTIONS, NULL },
 964	.tosec   = { ALL_EXIT_SECTIONS, NULL },
 965	.mismatch = TEXT_TO_ANY_EXIT,
 966	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 967},
 968{
 969	.fromsec = { DATA_SECTIONS, NULL },
 970	.tosec   = { ALL_EXIT_SECTIONS, NULL },
 971	.mismatch = DATA_TO_ANY_EXIT,
 972	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 973},
 974/* Do not reference init code/data from devinit/cpuinit/meminit code/data */
 975{
 976	.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
 977	.tosec   = { INIT_SECTIONS, NULL },
 978	.mismatch = XXXINIT_TO_SOME_INIT,
 979	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 980},
 981/* Do not reference cpuinit code/data from meminit code/data */
 982{
 983	.fromsec = { MEM_INIT_SECTIONS, NULL },
 984	.tosec   = { CPU_INIT_SECTIONS, NULL },
 985	.mismatch = XXXINIT_TO_SOME_INIT,
 986	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 987},
 988/* Do not reference meminit code/data from cpuinit code/data */
 989{
 990	.fromsec = { CPU_INIT_SECTIONS, NULL },
 991	.tosec   = { MEM_INIT_SECTIONS, NULL },
 992	.mismatch = XXXINIT_TO_SOME_INIT,
 993	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 994},
 995/* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
 996{
 997	.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
 998	.tosec   = { EXIT_SECTIONS, NULL },
 999	.mismatch = XXXEXIT_TO_SOME_EXIT,
1000	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1001},
1002/* Do not reference cpuexit code/data from memexit code/data */
1003{
1004	.fromsec = { MEM_EXIT_SECTIONS, NULL },
1005	.tosec   = { CPU_EXIT_SECTIONS, NULL },
1006	.mismatch = XXXEXIT_TO_SOME_EXIT,
1007	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1008},
1009/* Do not reference memexit code/data from cpuexit code/data */
1010{
1011	.fromsec = { CPU_EXIT_SECTIONS, NULL },
1012	.tosec   = { MEM_EXIT_SECTIONS, NULL },
1013	.mismatch = XXXEXIT_TO_SOME_EXIT,
1014	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1015},
1016/* Do not use exit code/data from init code */
1017{
1018	.fromsec = { ALL_INIT_SECTIONS, NULL },
1019	.tosec   = { ALL_EXIT_SECTIONS, NULL },
1020	.mismatch = ANY_INIT_TO_ANY_EXIT,
1021	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1022},
1023/* Do not use init code/data from exit code */
1024{
1025	.fromsec = { ALL_EXIT_SECTIONS, NULL },
1026	.tosec   = { ALL_INIT_SECTIONS, NULL },
1027	.mismatch = ANY_EXIT_TO_ANY_INIT,
1028	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1029},
1030/* Do not export init/exit functions or data */
1031{
1032	.fromsec = { "__ksymtab*", NULL },
1033	.tosec   = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1034	.mismatch = EXPORT_TO_INIT_EXIT,
1035	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1036}
1037};
1038
1039static const struct sectioncheck *section_mismatch(
1040		const char *fromsec, const char *tosec)
1041{
1042	int i;
1043	int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1044	const struct sectioncheck *check = &sectioncheck[0];
1045
1046	for (i = 0; i < elems; i++) {
1047		if (match(fromsec, check->fromsec) &&
1048		    match(tosec, check->tosec))
1049			return check;
1050		check++;
1051	}
1052	return NULL;
1053}
1054
1055/**
1056 * Whitelist to allow certain references to pass with no warning.
1057 *
1058 * Pattern 1:
1059 *   If a module parameter is declared __initdata and permissions=0
1060 *   then this is legal despite the warning generated.
1061 *   We cannot see value of permissions here, so just ignore
1062 *   this pattern.
1063 *   The pattern is identified by:
1064 *   tosec   = .init.data
1065 *   fromsec = .data*
1066 *   atsym   =__param*
1067 *
1068 * Pattern 1a:
1069 *   module_param_call() ops can refer to __init set function if permissions=0
1070 *   The pattern is identified by:
1071 *   tosec   = .init.text
1072 *   fromsec = .data*
1073 *   atsym   = __param_ops_*
1074 *
1075 * Pattern 2:
1076 *   Many drivers utilise a *driver container with references to
1077 *   add, remove, probe functions etc.
1078 *   These functions may often be marked __devinit and we do not want to
1079 *   warn here.
1080 *   the pattern is identified by:
1081 *   tosec   = init or exit section
1082 *   fromsec = data section
1083 *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1084 *           *probe_one, *_console, *_timer
1085 *
1086 * Pattern 3:
1087 *   Whitelist all references from .head.text to any init section
1088 *
1089 * Pattern 4:
1090 *   Some symbols belong to init section but still it is ok to reference
1091 *   these from non-init sections as these symbols don't have any memory
1092 *   allocated for them and symbol address and value are same. So even
1093 *   if init section is freed, its ok to reference those symbols.
1094 *   For ex. symbols marking the init section boundaries.
1095 *   This pattern is identified by
1096 *   refsymname = __init_begin, _sinittext, _einittext
1097 *
1098 **/
1099static int secref_whitelist(const struct sectioncheck *mismatch,
1100			    const char *fromsec, const char *fromsym,
1101			    const char *tosec, const char *tosym)
1102{
1103	/* Check for pattern 1 */
1104	if (match(tosec, init_data_sections) &&
1105	    match(fromsec, data_sections) &&
1106	    (strncmp(fromsym, "__param", strlen("__param")) == 0))
1107		return 0;
1108
1109	/* Check for pattern 1a */
1110	if (strcmp(tosec, ".init.text") == 0 &&
1111	    match(fromsec, data_sections) &&
1112	    (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1113		return 0;
1114
1115	/* Check for pattern 2 */
1116	if (match(tosec, init_exit_sections) &&
1117	    match(fromsec, data_sections) &&
1118	    match(fromsym, mismatch->symbol_white_list))
1119		return 0;
1120
1121	/* Check for pattern 3 */
1122	if (match(fromsec, head_sections) &&
1123	    match(tosec, init_sections))
1124		return 0;
1125
1126	/* Check for pattern 4 */
1127	if (match(tosym, linker_symbols))
1128		return 0;
1129
1130	return 1;
1131}
1132
1133/**
1134 * Find symbol based on relocation record info.
1135 * In some cases the symbol supplied is a valid symbol so
1136 * return refsym. If st_name != 0 we assume this is a valid symbol.
1137 * In other cases the symbol needs to be looked up in the symbol table
1138 * based on section and address.
1139 *  **/
1140static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1141				Elf_Sym *relsym)
1142{
1143	Elf_Sym *sym;
1144	Elf_Sym *near = NULL;
1145	Elf64_Sword distance = 20;
1146	Elf64_Sword d;
1147	unsigned int relsym_secindex;
1148
1149	if (relsym->st_name != 0)
1150		return relsym;
1151
1152	relsym_secindex = get_secindex(elf, relsym);
1153	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1154		if (get_secindex(elf, sym) != relsym_secindex)
1155			continue;
1156		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1157			continue;
1158		if (sym->st_value == addr)
1159			return sym;
1160		/* Find a symbol nearby - addr are maybe negative */
1161		d = sym->st_value - addr;
1162		if (d < 0)
1163			d = addr - sym->st_value;
1164		if (d < distance) {
1165			distance = d;
1166			near = sym;
1167		}
1168	}
1169	/* We need a close match */
1170	if (distance < 20)
1171		return near;
1172	else
1173		return NULL;
1174}
1175
1176static inline int is_arm_mapping_symbol(const char *str)
1177{
1178	return str[0] == '$' && strchr("atd", str[1])
1179	       && (str[2] == '\0' || str[2] == '.');
1180}
1181
1182/*
1183 * If there's no name there, ignore it; likewise, ignore it if it's
1184 * one of the magic symbols emitted used by current ARM tools.
1185 *
1186 * Otherwise if find_symbols_between() returns those symbols, they'll
1187 * fail the whitelist tests and cause lots of false alarms ... fixable
1188 * only by merging __exit and __init sections into __text, bloating
1189 * the kernel (which is especially evil on embedded platforms).
1190 */
1191static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1192{
1193	const char *name = elf->strtab + sym->st_name;
1194
1195	if (!name || !strlen(name))
1196		return 0;
1197	return !is_arm_mapping_symbol(name);
1198}
1199
1200/*
1201 * Find symbols before or equal addr and after addr - in the section sec.
1202 * If we find two symbols with equal offset prefer one with a valid name.
1203 * The ELF format may have a better way to detect what type of symbol
1204 * it is, but this works for now.
1205 **/
1206static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1207				 const char *sec)
1208{
1209	Elf_Sym *sym;
1210	Elf_Sym *near = NULL;
1211	Elf_Addr distance = ~0;
1212
1213	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1214		const char *symsec;
1215
1216		if (is_shndx_special(sym->st_shndx))
1217			continue;
1218		symsec = sec_name(elf, get_secindex(elf, sym));
1219		if (strcmp(symsec, sec) != 0)
1220			continue;
1221		if (!is_valid_name(elf, sym))
1222			continue;
1223		if (sym->st_value <= addr) {
1224			if ((addr - sym->st_value) < distance) {
1225				distance = addr - sym->st_value;
1226				near = sym;
1227			} else if ((addr - sym->st_value) == distance) {
1228				near = sym;
1229			}
1230		}
1231	}
1232	return near;
1233}
1234
1235/*
1236 * Convert a section name to the function/data attribute
1237 * .init.text => __init
1238 * .cpuinit.data => __cpudata
1239 * .memexitconst => __memconst
1240 * etc.
1241 *
1242 * The memory of returned value has been allocated on a heap. The user of this
1243 * method should free it after usage.
1244*/
1245static char *sec2annotation(const char *s)
1246{
1247	if (match(s, init_exit_sections)) {
1248		char *p = malloc(20);
1249		char *r = p;
1250
1251		*p++ = '_';
1252		*p++ = '_';
1253		if (*s == '.')
1254			s++;
1255		while (*s && *s != '.')
1256			*p++ = *s++;
1257		*p = '\0';
1258		if (*s == '.')
1259			s++;
1260		if (strstr(s, "rodata") != NULL)
1261			strcat(p, "const ");
1262		else if (strstr(s, "data") != NULL)
1263			strcat(p, "data ");
1264		else
1265			strcat(p, " ");
1266		return r;
1267	} else {
1268		return strdup("");
1269	}
1270}
1271
1272static int is_function(Elf_Sym *sym)
1273{
1274	if (sym)
1275		return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1276	else
1277		return -1;
1278}
1279
1280static void print_section_list(const char * const list[20])
1281{
1282	const char *const *s = list;
1283
1284	while (*s) {
1285		fprintf(stderr, "%s", *s);
1286		s++;
1287		if (*s)
1288			fprintf(stderr, ", ");
1289	}
1290	fprintf(stderr, "\n");
1291}
1292
1293/*
1294 * Print a warning about a section mismatch.
1295 * Try to find symbols near it so user can find it.
1296 * Check whitelist before warning - it may be a false positive.
1297 */
1298static void report_sec_mismatch(const char *modname,
1299				const struct sectioncheck *mismatch,
1300                                const char *fromsec,
1301                                unsigned long long fromaddr,
1302                                const char *fromsym,
1303                                int from_is_func,
1304                                const char *tosec, const char *tosym,
1305                                int to_is_func)
1306{
1307	const char *from, *from_p;
1308	const char *to, *to_p;
1309	char *prl_from;
1310	char *prl_to;
1311
1312	switch (from_is_func) {
1313	case 0: from = "variable"; from_p = "";   break;
1314	case 1: from = "function"; from_p = "()"; break;
1315	default: from = "(unknown reference)"; from_p = ""; break;
1316	}
1317	switch (to_is_func) {
1318	case 0: to = "variable"; to_p = "";   break;
1319	case 1: to = "function"; to_p = "()"; break;
1320	default: to = "(unknown reference)"; to_p = ""; break;
1321	}
1322
1323	sec_mismatch_count++;
1324	if (!sec_mismatch_verbose)
1325		return;
1326
1327	warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1328	     "to the %s %s:%s%s\n",
1329	     modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1330	     tosym, to_p);
1331
1332	switch (mismatch->mismatch) {
1333	case TEXT_TO_ANY_INIT:
1334		prl_from = sec2annotation(fromsec);
1335		prl_to = sec2annotation(tosec);
1336		fprintf(stderr,
1337		"The function %s%s() references\n"
1338		"the %s %s%s%s.\n"
1339		"This is often because %s lacks a %s\n"
1340		"annotation or the annotation of %s is wrong.\n",
1341		prl_from, fromsym,
1342		to, prl_to, tosym, to_p,
1343		fromsym, prl_to, tosym);
1344		free(prl_from);
1345		free(prl_to);
1346		break;
1347	case DATA_TO_ANY_INIT: {
1348		prl_to = sec2annotation(tosec);
1349		fprintf(stderr,
1350		"The variable %s references\n"
1351		"the %s %s%s%s\n"
1352		"If the reference is valid then annotate the\n"
1353		"variable with __init* or __refdata (see linux/init.h) "
1354		"or name the variable:\n",
1355		fromsym, to, prl_to, tosym, to_p);
1356		print_section_list(mismatch->symbol_white_list);
1357		free(prl_to);
1358		break;
1359	}
1360	case TEXT_TO_ANY_EXIT:
1361		prl_to = sec2annotation(tosec);
1362		fprintf(stderr,
1363		"The function %s() references a %s in an exit section.\n"
1364		"Often the %s %s%s has valid usage outside the exit section\n"
1365		"and the fix is to remove the %sannotation of %s.\n",
1366		fromsym, to, to, tosym, to_p, prl_to, tosym);
1367		free(prl_to);
1368		break;
1369	case DATA_TO_ANY_EXIT: {
1370		prl_to = sec2annotation(tosec);
1371		fprintf(stderr,
1372		"The variable %s references\n"
1373		"the %s %s%s%s\n"
1374		"If the reference is valid then annotate the\n"
1375		"variable with __exit* (see linux/init.h) or "
1376		"name the variable:\n",
1377		fromsym, to, prl_to, tosym, to_p);
1378		print_section_list(mismatch->symbol_white_list);
1379		free(prl_to);
1380		break;
1381	}
1382	case XXXINIT_TO_SOME_INIT:
1383	case XXXEXIT_TO_SOME_EXIT:
1384		prl_from = sec2annotation(fromsec);
1385		prl_to = sec2annotation(tosec);
1386		fprintf(stderr,
1387		"The %s %s%s%s references\n"
1388		"a %s %s%s%s.\n"
1389		"If %s is only used by %s then\n"
1390		"annotate %s with a matching annotation.\n",
1391		from, prl_from, fromsym, from_p,
1392		to, prl_to, tosym, to_p,
1393		tosym, fromsym, tosym);
1394		free(prl_from);
1395		free(prl_to);
1396		break;
1397	case ANY_INIT_TO_ANY_EXIT:
1398		prl_from = sec2annotation(fromsec);
1399		prl_to = sec2annotation(tosec);
1400		fprintf(stderr,
1401		"The %s %s%s%s references\n"
1402		"a %s %s%s%s.\n"
1403		"This is often seen when error handling "
1404		"in the init function\n"
1405		"uses functionality in the exit path.\n"
1406		"The fix is often to remove the %sannotation of\n"
1407		"%s%s so it may be used outside an exit section.\n",
1408		from, prl_from, fromsym, from_p,
1409		to, prl_to, tosym, to_p,
1410		prl_to, tosym, to_p);
1411		free(prl_from);
1412		free(prl_to);
1413		break;
1414	case ANY_EXIT_TO_ANY_INIT:
1415		prl_from = sec2annotation(fromsec);
1416		prl_to = sec2annotation(tosec);
1417		fprintf(stderr,
1418		"The %s %s%s%s references\n"
1419		"a %s %s%s%s.\n"
1420		"This is often seen when error handling "
1421		"in the exit function\n"
1422		"uses functionality in the init path.\n"
1423		"The fix is often to remove the %sannotation of\n"
1424		"%s%s so it may be used outside an init section.\n",
1425		from, prl_from, fromsym, from_p,
1426		to, prl_to, tosym, to_p,
1427		prl_to, tosym, to_p);
1428		free(prl_from);
1429		free(prl_to);
1430		break;
1431	case EXPORT_TO_INIT_EXIT:
1432		prl_to = sec2annotation(tosec);
1433		fprintf(stderr,
1434		"The symbol %s is exported and annotated %s\n"
1435		"Fix this by removing the %sannotation of %s "
1436		"or drop the export.\n",
1437		tosym, prl_to, prl_to, tosym);
1438		free(prl_to);
1439		break;
1440	}
1441	fprintf(stderr, "\n");
1442}
1443
1444static void check_section_mismatch(const char *modname, struct elf_info *elf,
1445                                   Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1446{
1447	const char *tosec;
1448	const struct sectioncheck *mismatch;
1449
1450	tosec = sec_name(elf, get_secindex(elf, sym));
1451	mismatch = section_mismatch(fromsec, tosec);
1452	if (mismatch) {
1453		Elf_Sym *to;
1454		Elf_Sym *from;
1455		const char *tosym;
1456		const char *fromsym;
1457
1458		from = find_elf_symbol2(elf, r->r_offset, fromsec);
1459		fromsym = sym_name(elf, from);
1460		to = find_elf_symbol(elf, r->r_addend, sym);
1461		tosym = sym_name(elf, to);
1462
1463		/* check whitelist - we may ignore it */
1464		if (secref_whitelist(mismatch,
1465					fromsec, fromsym, tosec, tosym)) {
1466			report_sec_mismatch(modname, mismatch,
1467			   fromsec, r->r_offset, fromsym,
1468			   is_function(from), tosec, tosym,
1469			   is_function(to));
1470		}
1471	}
1472}
1473
1474static unsigned int *reloc_location(struct elf_info *elf,
1475				    Elf_Shdr *sechdr, Elf_Rela *r)
1476{
1477	Elf_Shdr *sechdrs = elf->sechdrs;
1478	int section = sechdr->sh_info;
1479
1480	return (void *)elf->hdr + sechdrs[section].sh_offset +
1481		r->r_offset;
1482}
1483
1484static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1485{
1486	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1487	unsigned int *location = reloc_location(elf, sechdr, r);
1488
1489	switch (r_typ) {
1490	case R_386_32:
1491		r->r_addend = TO_NATIVE(*location);
1492		break;
1493	case R_386_PC32:
1494		r->r_addend = TO_NATIVE(*location) + 4;
1495		/* For CONFIG_RELOCATABLE=y */
1496		if (elf->hdr->e_type == ET_EXEC)
1497			r->r_addend += r->r_offset;
1498		break;
1499	}
1500	return 0;
1501}
1502
1503#ifndef R_ARM_CALL
1504#define R_ARM_CALL	28
1505#endif
1506#ifndef R_ARM_JUMP24
1507#define R_ARM_JUMP24	29
1508#endif
1509
1510static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1511{
1512	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1513
1514	switch (r_typ) {
1515	case R_ARM_ABS32:
1516		/* From ARM ABI: (S + A) | T */
1517		r->r_addend = (int)(long)
1518		              (elf->symtab_start + ELF_R_SYM(r->r_info));
1519		break;
1520	case R_ARM_PC24:
1521	case R_ARM_CALL:
1522	case R_ARM_JUMP24:
1523		/* From ARM ABI: ((S + A) | T) - P */
1524		r->r_addend = (int)(long)(elf->hdr +
1525		              sechdr->sh_offset +
1526		              (r->r_offset - sechdr->sh_addr));
1527		break;
1528	default:
1529		return 1;
1530	}
1531	return 0;
1532}
1533
1534static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1535{
1536	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1537	unsigned int *location = reloc_location(elf, sechdr, r);
1538	unsigned int inst;
1539
1540	if (r_typ == R_MIPS_HI16)
1541		return 1;	/* skip this */
1542	inst = TO_NATIVE(*location);
1543	switch (r_typ) {
1544	case R_MIPS_LO16:
1545		r->r_addend = inst & 0xffff;
1546		break;
1547	case R_MIPS_26:
1548		r->r_addend = (inst & 0x03ffffff) << 2;
1549		break;
1550	case R_MIPS_32:
1551		r->r_addend = inst;
1552		break;
1553	}
1554	return 0;
1555}
1556
1557static void section_rela(const char *modname, struct elf_info *elf,
1558                         Elf_Shdr *sechdr)
1559{
1560	Elf_Sym  *sym;
1561	Elf_Rela *rela;
1562	Elf_Rela r;
1563	unsigned int r_sym;
1564	const char *fromsec;
1565
1566	Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1567	Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1568
1569	fromsec = sech_name(elf, sechdr);
1570	fromsec += strlen(".rela");
1571	/* if from section (name) is know good then skip it */
1572	if (match(fromsec, section_white_list))
1573		return;
1574
1575	for (rela = start; rela < stop; rela++) {
1576		r.r_offset = TO_NATIVE(rela->r_offset);
1577#if KERNEL_ELFCLASS == ELFCLASS64
1578		if (elf->hdr->e_machine == EM_MIPS) {
1579			unsigned int r_typ;
1580			r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1581			r_sym = TO_NATIVE(r_sym);
1582			r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1583			r.r_info = ELF64_R_INFO(r_sym, r_typ);
1584		} else {
1585			r.r_info = TO_NATIVE(rela->r_info);
1586			r_sym = ELF_R_SYM(r.r_info);
1587		}
1588#else
1589		r.r_info = TO_NATIVE(rela->r_info);
1590		r_sym = ELF_R_SYM(r.r_info);
1591#endif
1592		r.r_addend = TO_NATIVE(rela->r_addend);
1593		sym = elf->symtab_start + r_sym;
1594		/* Skip special sections */
1595		if (is_shndx_special(sym->st_shndx))
1596			continue;
1597		check_section_mismatch(modname, elf, &r, sym, fromsec);
1598	}
1599}
1600
1601static void section_rel(const char *modname, struct elf_info *elf,
1602                        Elf_Shdr *sechdr)
1603{
1604	Elf_Sym *sym;
1605	Elf_Rel *rel;
1606	Elf_Rela r;
1607	unsigned int r_sym;
1608	const char *fromsec;
1609
1610	Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1611	Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1612
1613	fromsec = sech_name(elf, sechdr);
1614	fromsec += strlen(".rel");
1615	/* if from section (name) is know good then skip it */
1616	if (match(fromsec, section_white_list))
1617		return;
1618
1619	for (rel = start; rel < stop; rel++) {
1620		r.r_offset = TO_NATIVE(rel->r_offset);
1621#if KERNEL_ELFCLASS == ELFCLASS64
1622		if (elf->hdr->e_machine == EM_MIPS) {
1623			unsigned int r_typ;
1624			r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1625			r_sym = TO_NATIVE(r_sym);
1626			r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1627			r.r_info = ELF64_R_INFO(r_sym, r_typ);
1628		} else {
1629			r.r_info = TO_NATIVE(rel->r_info);
1630			r_sym = ELF_R_SYM(r.r_info);
1631		}
1632#else
1633		r.r_info = TO_NATIVE(rel->r_info);
1634		r_sym = ELF_R_SYM(r.r_info);
1635#endif
1636		r.r_addend = 0;
1637		switch (elf->hdr->e_machine) {
1638		case EM_386:
1639			if (addend_386_rel(elf, sechdr, &r))
1640				continue;
1641			break;
1642		case EM_ARM:
1643			if (addend_arm_rel(elf, sechdr, &r))
1644				continue;
1645			break;
1646		case EM_MIPS:
1647			if (addend_mips_rel(elf, sechdr, &r))
1648				continue;
1649			break;
1650		}
1651		sym = elf->symtab_start + r_sym;
1652		/* Skip special sections */
1653		if (is_shndx_special(sym->st_shndx))
1654			continue;
1655		check_section_mismatch(modname, elf, &r, sym, fromsec);
1656	}
1657}
1658
1659/**
1660 * A module includes a number of sections that are discarded
1661 * either when loaded or when used as built-in.
1662 * For loaded modules all functions marked __init and all data
1663 * marked __initdata will be discarded when the module has been initialized.
1664 * Likewise for modules used built-in the sections marked __exit
1665 * are discarded because __exit marked function are supposed to be called
1666 * only when a module is unloaded which never happens for built-in modules.
1667 * The check_sec_ref() function traverses all relocation records
1668 * to find all references to a section that reference a section that will
1669 * be discarded and warns about it.
1670 **/
1671static void check_sec_ref(struct module *mod, const char *modname,
1672                          struct elf_info *elf)
1673{
1674	int i;
1675	Elf_Shdr *sechdrs = elf->sechdrs;
1676
1677	/* Walk through all sections */
1678	for (i = 0; i < elf->num_sections; i++) {
1679		check_section(modname, elf, &elf->sechdrs[i]);
1680		/* We want to process only relocation sections and not .init */
1681		if (sechdrs[i].sh_type == SHT_RELA)
1682			section_rela(modname, elf, &elf->sechdrs[i]);
1683		else if (sechdrs[i].sh_type == SHT_REL)
1684			section_rel(modname, elf, &elf->sechdrs[i]);
1685	}
1686}
1687
1688static void read_symbols(char *modname)
1689{
1690	const char *symname;
1691	char *version;
1692	char *license;
1693	struct module *mod;
1694	struct elf_info info = { };
1695	Elf_Sym *sym;
1696
1697	if (!parse_elf(&info, modname))
1698		return;
1699
1700	mod = new_module(modname);
1701
1702	/* When there's no vmlinux, don't print warnings about
1703	 * unresolved symbols (since there'll be too many ;) */
1704	if (is_vmlinux(modname)) {
1705		have_vmlinux = 1;
1706		mod->skip = 1;
1707	}
1708
1709	license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1710	if (info.modinfo && !license && !is_vmlinux(modname))
1711		warn("modpost: missing MODULE_LICENSE() in %s\n"
1712		     "see include/linux/module.h for "
1713		     "more information\n", modname);
1714	while (license) {
1715		if (license_is_gpl_compatible(license))
1716			mod->gpl_compatible = 1;
1717		else {
1718			mod->gpl_compatible = 0;
1719			break;
1720		}
1721		license = get_next_modinfo(info.modinfo, info.modinfo_len,
1722					   "license", license);
1723	}
1724
1725	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1726		symname = info.strtab + sym->st_name;
1727
1728		handle_modversions(mod, &info, sym, symname);
1729		handle_moddevtable(mod, &info, sym, symname);
1730	}
1731	if (!is_vmlinux(modname) ||
1732	     (is_vmlinux(modname) && vmlinux_section_warnings))
1733		check_sec_ref(mod, modname, &info);
1734
1735	version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1736	if (version)
1737		maybe_frob_rcs_version(modname, version, info.modinfo,
1738				       version - (char *)info.hdr);
1739	if (version || (all_versions && !is_vmlinux(modname)))
1740		get_src_version(modname, mod->srcversion,
1741				sizeof(mod->srcversion)-1);
1742
1743	parse_elf_finish(&info);
1744
1745	/* Our trick to get versioning for module struct etc. - it's
1746	 * never passed as an argument to an exported function, so
1747	 * the automatic versioning doesn't pick it up, but it's really
1748	 * important anyhow */
1749	if (modversions)
1750		mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1751}
1752
1753#define SZ 500
1754
1755/* We first write the generated file into memory using the
1756 * following helper, then compare to the file on disk and
1757 * only update the later if anything changed */
1758
1759void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1760						      const char *fmt, ...)
1761{
1762	char tmp[SZ];
1763	int len;
1764	va_list ap;
1765
1766	va_start(ap, fmt);
1767	len = vsnprintf(tmp, SZ, fmt, ap);
1768	buf_write(buf, tmp, len);
1769	va_end(ap);
1770}
1771
1772void buf_write(struct buffer *buf, const char *s, int len)
1773{
1774	if (buf->size - buf->pos < len) {
1775		buf->size += len + SZ;
1776		buf->p = realloc(buf->p, buf->size);
1777	}
1778	strncpy(buf->p + buf->pos, s, len);
1779	buf->pos += len;
1780}
1781
1782static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1783{
1784	const char *e = is_vmlinux(m) ?"":".ko";
1785
1786	switch (exp) {
1787	case export_gpl:
1788		fatal("modpost: GPL-incompatible module %s%s "
1789		      "uses GPL-only symbol '%s'\n", m, e, s);
1790		break;
1791	case export_unused_gpl:
1792		fatal("modpost: GPL-incompatible module %s%s "
1793		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1794		break;
1795	case export_gpl_future:
1796		warn("modpost: GPL-incompatible module %s%s "
1797		      "uses future GPL-only symbol '%s'\n", m, e, s);
1798		break;
1799	case export_plain:
1800	case export_unused:
1801	case export_unknown:
1802		/* ignore */
1803		break;
1804	}
1805}
1806
1807static void check_for_unused(enum export exp, const char *m, const char *s)
1808{
1809	const char *e = is_vmlinux(m) ?"":".ko";
1810
1811	switch (exp) {
1812	case export_unused:
1813	case export_unused_gpl:
1814		warn("modpost: module %s%s "
1815		      "uses symbol '%s' marked UNUSED\n", m, e, s);
1816		break;
1817	default:
1818		/* ignore */
1819		break;
1820	}
1821}
1822
1823static void check_exports(struct module *mod)
1824{
1825	struct symbol *s, *exp;
1826
1827	for (s = mod->unres; s; s = s->next) {
1828		const char *basename;
1829		exp = find_symbol(s->name);
1830		if (!exp || exp->module == mod)
1831			continue;
1832		basename = strrchr(mod->name, '/');
1833		if (basename)
1834			basename++;
1835		else
1836			basename = mod->name;
1837		if (!mod->gpl_compatible)
1838			check_for_gpl_usage(exp->export, basename, exp->name);
1839		check_for_unused(exp->export, basename, exp->name);
1840	}
1841}
1842
1843/**
1844 * Header for the generated file
1845 **/
1846static void add_header(struct buffer *b, struct module *mod)
1847{
1848	buf_printf(b, "#include <linux/module.h>\n");
1849	buf_printf(b, "#include <linux/vermagic.h>\n");
1850	buf_printf(b, "#include <linux/compiler.h>\n");
1851	buf_printf(b, "\n");
1852	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1853	buf_printf(b, "\n");
1854	buf_printf(b, "struct module __this_module\n");
1855	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1856	buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1857	if (mod->has_init)
1858		buf_printf(b, "\t.init = init_module,\n");
1859	if (mod->has_cleanup)
1860		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1861			      "\t.exit = cleanup_module,\n"
1862			      "#endif\n");
1863	buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1864	buf_printf(b, "};\n");
1865}
1866
1867static void add_intree_flag(struct buffer *b, int is_intree)
1868{
1869	if (is_intree)
1870		buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1871}
1872
1873static void add_staging_flag(struct buffer *b, const char *name)
1874{
1875	static const char *staging_dir = "drivers/staging";
1876
1877	if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1878		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1879}
1880
1881/**
1882 * Record CRCs for unresolved symbols
1883 **/
1884static int add_versions(struct buffer *b, struct module *mod)
1885{
1886	struct symbol *s, *exp;
1887	int err = 0;
1888
1889	for (s = mod->unres; s; s = s->next) {
1890		exp = find_symbol(s->name);
1891		if (!exp || exp->module == mod) {
1892			if (have_vmlinux && !s->weak) {
1893				if (warn_unresolved) {
1894					warn("\"%s\" [%s.ko] undefined!\n",
1895					     s->name, mod->name);
1896				} else {
1897					merror("\"%s\" [%s.ko] undefined!\n",
1898					          s->name, mod->name);
1899					err = 1;
1900				}
1901			}
1902			continue;
1903		}
1904		s->module = exp->module;
1905		s->crc_valid = exp->crc_valid;
1906		s->crc = exp->crc;
1907	}
1908
1909	if (!modversions)
1910		return err;
1911
1912	buf_printf(b, "\n");
1913	buf_printf(b, "static const struct modversion_info ____versions[]\n");
1914	buf_printf(b, "__used\n");
1915	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1916
1917	for (s = mod->unres; s; s = s->next) {
1918		if (!s->module)
1919			continue;
1920		if (!s->crc_valid) {
1921			warn("\"%s\" [%s.ko] has no CRC!\n",
1922				s->name, mod->name);
1923			continue;
1924		}
1925		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1926	}
1927
1928	buf_printf(b, "};\n");
1929
1930	return err;
1931}
1932
1933static void add_depends(struct buffer *b, struct module *mod,
1934			struct module *modules)
1935{
1936	struct symbol *s;
1937	struct module *m;
1938	int first = 1;
1939
1940	for (m = modules; m; m = m->next)
1941		m->seen = is_vmlinux(m->name);
1942
1943	buf_printf(b, "\n");
1944	buf_printf(b, "static const char __module_depends[]\n");
1945	buf_printf(b, "__used\n");
1946	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1947	buf_printf(b, "\"depends=");
1948	for (s = mod->unres; s; s = s->next) {
1949		const char *p;
1950		if (!s->module)
1951			continue;
1952
1953		if (s->module->seen)
1954			continue;
1955
1956		s->module->seen = 1;
1957		p = strrchr(s->module->name, '/');
1958		if (p)
1959			p++;
1960		else
1961			p = s->module->name;
1962		buf_printf(b, "%s%s", first ? "" : ",", p);
1963		first = 0;
1964	}
1965	buf_printf(b, "\";\n");
1966}
1967
1968static void add_srcversion(struct buffer *b, struct module *mod)
1969{
1970	if (mod->srcversion[0]) {
1971		buf_printf(b, "\n");
1972		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1973			   mod->srcversion);
1974	}
1975}
1976
1977static void write_if_changed(struct buffer *b, const char *fname)
1978{
1979	char *tmp;
1980	FILE *file;
1981	struct stat st;
1982
1983	file = fopen(fname, "r");
1984	if (!file)
1985		goto write;
1986
1987	if (fstat(fileno(file), &st) < 0)
1988		goto close_write;
1989
1990	if (st.st_size != b->pos)
1991		goto close_write;
1992
1993	tmp = NOFAIL(malloc(b->pos));
1994	if (fread(tmp, 1, b->pos, file) != b->pos)
1995		goto free_write;
1996
1997	if (memcmp(tmp, b->p, b->pos) != 0)
1998		goto free_write;
1999
2000	free(tmp);
2001	fclose(file);
2002	return;
2003
2004 free_write:
2005	free(tmp);
2006 close_write:
2007	fclose(file);
2008 write:
2009	file = fopen(fname, "w");
2010	if (!file) {
2011		perror(fname);
2012		exit(1);
2013	}
2014	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2015		perror(fname);
2016		exit(1);
2017	}
2018	fclose(file);
2019}
2020
2021/* parse Module.symvers file. line format:
2022 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2023 **/
2024static void read_dump(const char *fname, unsigned int kernel)
2025{
2026	unsigned long size, pos = 0;
2027	void *file = grab_file(fname, &size);
2028	char *line;
2029
2030	if (!file)
2031		/* No symbol versions, silently ignore */
2032		return;
2033
2034	while ((line = get_next_line(&pos, file, size))) {
2035		char *symname, *modname, *d, *export, *end;
2036		unsigned int crc;
2037		struct module *mod;
2038		struct symbol *s;
2039
2040		if (!(symname = strchr(line, '\t')))
2041			goto fail;
2042		*symname++ = '\0';
2043		if (!(modname = strchr(symname, '\t')))
2044			goto fail;
2045		*modname++ = '\0';
2046		if ((export = strchr(modname, '\t')) != NULL)
2047			*export++ = '\0';
2048		if (export && ((end = strchr(export, '\t')) != NULL))
2049			*end = '\0';
2050		crc = strtoul(line, &d, 16);
2051		if (*symname == '\0' || *modname == '\0' || *d != '\0')
2052			goto fail;
2053		mod = find_module(modname);
2054		if (!mod) {
2055			if (is_vmlinux(modname))
2056				have_vmlinux = 1;
2057			mod = new_module(modname);
2058			mod->skip = 1;
2059		}
2060		s = sym_add_exported(symname, mod, export_no(export));
2061		s->kernel    = kernel;
2062		s->preloaded = 1;
2063		sym_update_crc(symname, mod, crc, export_no(export));
2064	}
2065	return;
2066fail:
2067	fatal("parse error in symbol dump file\n");
2068}
2069
2070/* For normal builds always dump all symbols.
2071 * For external modules only dump symbols
2072 * that are not read from kernel Module.symvers.
2073 **/
2074static int dump_sym(struct symbol *sym)
2075{
2076	if (!external_module)
2077		return 1;
2078	if (sym->vmlinux || sym->kernel)
2079		return 0;
2080	return 1;
2081}
2082
2083static void write_dump(const char *fname)
2084{
2085	struct buffer buf = { };
2086	struct symbol *symbol;
2087	int n;
2088
2089	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2090		symbol = symbolhash[n];
2091		while (symbol) {
2092			if (dump_sym(symbol))
2093				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2094					symbol->crc, symbol->name,
2095					symbol->module->name,
2096					export_str(symbol->export));
2097			symbol = symbol->next;
2098		}
2099	}
2100	write_if_changed(&buf, fname);
2101}
2102
2103struct ext_sym_list {
2104	struct ext_sym_list *next;
2105	const char *file;
2106};
2107
2108int main(int argc, char **argv)
2109{
2110	struct module *mod;
2111	struct buffer buf = { };
2112	char *kernel_read = NULL, *module_read = NULL;
2113	char *dump_write = NULL;
2114	int opt;
2115	int err;
2116	struct ext_sym_list *extsym_iter;
2117	struct ext_sym_list *extsym_start = NULL;
2118
2119	while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2120		switch (opt) {
2121		case 'i':
2122			kernel_read = optarg;
2123			break;
2124		case 'I':
2125			module_read = optarg;
2126			external_module = 1;
2127			break;
2128		case 'c':
2129			cross_build = 1;
2130			break;
2131		case 'e':
2132			external_module = 1;
2133			extsym_iter =
2134			   NOFAIL(malloc(sizeof(*extsym_iter)));
2135			extsym_iter->next = extsym_start;
2136			extsym_iter->file = optarg;
2137			extsym_start = extsym_iter;
2138			break;
2139		case 'm':
2140			modversions = 1;
2141			break;
2142		case 'o':
2143			dump_write = optarg;
2144			break;
2145		case 'a':
2146			all_versions = 1;
2147			break;
2148		case 's':
2149			vmlinux_section_warnings = 0;
2150			break;
2151		case 'S':
2152			sec_mismatch_verbose = 0;
2153			break;
2154		case 'w':
2155			warn_unresolved = 1;
2156			break;
2157		default:
2158			exit(1);
2159		}
2160	}
2161
2162	if (kernel_read)
2163		read_dump(kernel_read, 1);
2164	if (module_read)
2165		read_dump(module_read, 0);
2166	while (extsym_start) {
2167		read_dump(extsym_start->file, 0);
2168		extsym_iter = extsym_start->next;
2169		free(extsym_start);
2170		extsym_start = extsym_iter;
2171	}
2172
2173	while (optind < argc)
2174		read_symbols(argv[optind++]);
2175
2176	for (mod = modules; mod; mod = mod->next) {
2177		if (mod->skip)
2178			continue;
2179		check_exports(mod);
2180	}
2181
2182	err = 0;
2183
2184	for (mod = modules; mod; mod = mod->next) {
2185		char fname[strlen(mod->name) + 10];
2186
2187		if (mod->skip)
2188			continue;
2189
2190		buf.pos = 0;
2191
2192		add_header(&buf, mod);
2193		add_intree_flag(&buf, !external_module);
2194		add_staging_flag(&buf, mod->name);
2195		err |= add_versions(&buf, mod);
2196		add_depends(&buf, mod, modules);
2197		add_moddevtable(&buf, mod);
2198		add_srcversion(&buf, mod);
2199
2200		sprintf(fname, "%s.mod.c", mod->name);
2201		write_if_changed(&buf, fname);
2202	}
2203
2204	if (dump_write)
2205		write_dump(dump_write);
2206	if (sec_mismatch_count && !sec_mismatch_verbose)
2207		warn("modpost: Found %d section mismatch(es).\n"
2208		     "To see full details build your kernel with:\n"
2209		     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2210		     sec_mismatch_count);
2211
2212	return err;
2213}