linux/scripts/mod/modpost.c
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   1/* Postprocess module symbol versions
   2 *
   3 * Copyright 2003       Kai Germaschewski
   4 * Copyright 2002-2004  Rusty Russell, IBM Corporation
   5 * Copyright 2006-2008  Sam Ravnborg
   6 * Based in part on module-init-tools/depmod.c,file2alias
   7 *
   8 * This software may be used and distributed according to the terms
   9 * of the GNU General Public License, incorporated herein by reference.
  10 *
  11 * Usage: modpost vmlinux module1.o module2.o ...
  12 */
  13
  14#define _GNU_SOURCE
  15#include <stdio.h>
  16#include <ctype.h>
  17#include <string.h>
  18#include "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
 138        /* add to list */
 139        mod->name = p;
 140        mod->gpl_compatible = -1;
 141        mod->next = modules;
 142        modules = mod;
 143
 144        return mod;
 145}
 146
 147/* A hash of all exported symbols,
 148 * struct symbol is also used for lists of unresolved symbols */
 149
 150#define SYMBOL_HASH_SIZE 1024
 151
 152struct symbol {
 153        struct symbol *next;
 154        struct module *module;
 155        unsigned int crc;
 156        int crc_valid;
 157        unsigned int weak:1;
 158        unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 159        unsigned int kernel:1;     /* 1 if symbol is from kernel
 160                                    *  (only for external modules) **/
 161        unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
 162        enum export  export;       /* Type of export */
 163        char name[0];
 164};
 165
 166static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 167
 168/* This is based on the hash agorithm from gdbm, via tdb */
 169static inline unsigned int tdb_hash(const char *name)
 170{
 171        unsigned value; /* Used to compute the hash value.  */
 172        unsigned   i;   /* Used to cycle through random values. */
 173
 174        /* Set the initial value from the key size. */
 175        for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 176                value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 177
 178        return (1103515243 * value + 12345);
 179}
 180
 181/**
 182 * Allocate a new symbols for use in the hash of exported symbols or
 183 * the list of unresolved symbols per module
 184 **/
 185static struct symbol *alloc_symbol(const char *name, unsigned int weak,
 186                                   struct symbol *next)
 187{
 188        struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 189
 190        memset(s, 0, sizeof(*s));
 191        strcpy(s->name, name);
 192        s->weak = weak;
 193        s->next = next;
 194        return s;
 195}
 196
 197/* For the hash of exported symbols */
 198static struct symbol *new_symbol(const char *name, struct module *module,
 199                                 enum export export)
 200{
 201        unsigned int hash;
 202        struct symbol *new;
 203
 204        hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
 205        new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
 206        new->module = module;
 207        new->export = export;
 208        return new;
 209}
 210
 211static struct symbol *find_symbol(const char *name)
 212{
 213        struct symbol *s;
 214
 215        /* For our purposes, .foo matches foo.  PPC64 needs this. */
 216        if (name[0] == '.')
 217                name++;
 218
 219        for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 220                if (strcmp(s->name, name) == 0)
 221                        return s;
 222        }
 223        return NULL;
 224}
 225
 226static struct {
 227        const char *str;
 228        enum export export;
 229} export_list[] = {
 230        { .str = "EXPORT_SYMBOL",            .export = export_plain },
 231        { .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 232        { .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 233        { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 234        { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 235        { .str = "(unknown)",                .export = export_unknown },
 236};
 237
 238
 239static const char *export_str(enum export ex)
 240{
 241        return export_list[ex].str;
 242}
 243
 244static enum export export_no(const char *s)
 245{
 246        int i;
 247
 248        if (!s)
 249                return export_unknown;
 250        for (i = 0; export_list[i].export != export_unknown; i++) {
 251                if (strcmp(export_list[i].str, s) == 0)
 252                        return export_list[i].export;
 253        }
 254        return export_unknown;
 255}
 256
 257static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 258{
 259        if (sec == elf->export_sec)
 260                return export_plain;
 261        else if (sec == elf->export_unused_sec)
 262                return export_unused;
 263        else if (sec == elf->export_gpl_sec)
 264                return export_gpl;
 265        else if (sec == elf->export_unused_gpl_sec)
 266                return export_unused_gpl;
 267        else if (sec == elf->export_gpl_future_sec)
 268                return export_gpl_future;
 269        else
 270                return export_unknown;
 271}
 272
 273/**
 274 * Add an exported symbol - it may have already been added without a
 275 * CRC, in this case just update the CRC
 276 **/
 277static struct symbol *sym_add_exported(const char *name, struct module *mod,
 278                                       enum export export)
 279{
 280        struct symbol *s = find_symbol(name);
 281
 282        if (!s) {
 283                s = new_symbol(name, mod, export);
 284        } else {
 285                if (!s->preloaded) {
 286                        warn("%s: '%s' exported twice. Previous export "
 287                             "was in %s%s\n", mod->name, name,
 288                             s->module->name,
 289                             is_vmlinux(s->module->name) ?"":".ko");
 290                } else {
 291                        /* In case Modules.symvers was out of date */
 292                        s->module = mod;
 293                }
 294        }
 295        s->preloaded = 0;
 296        s->vmlinux   = is_vmlinux(mod->name);
 297        s->kernel    = 0;
 298        s->export    = export;
 299        return s;
 300}
 301
 302static void sym_update_crc(const char *name, struct module *mod,
 303                           unsigned int crc, enum export export)
 304{
 305        struct symbol *s = find_symbol(name);
 306
 307        if (!s)
 308                s = new_symbol(name, mod, export);
 309        s->crc = crc;
 310        s->crc_valid = 1;
 311}
 312
 313void *grab_file(const char *filename, unsigned long *size)
 314{
 315        struct stat st;
 316        void *map;
 317        int fd;
 318
 319        fd = open(filename, O_RDONLY);
 320        if (fd < 0 || fstat(fd, &st) != 0)
 321                return NULL;
 322
 323        *size = st.st_size;
 324        map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 325        close(fd);
 326
 327        if (map == MAP_FAILED)
 328                return NULL;
 329        return map;
 330}
 331
 332/**
 333  * Return a copy of the next line in a mmap'ed file.
 334  * spaces in the beginning of the line is trimmed away.
 335  * Return a pointer to a static buffer.
 336  **/
 337char *get_next_line(unsigned long *pos, void *file, unsigned long size)
 338{
 339        static char line[4096];
 340        int skip = 1;
 341        size_t len = 0;
 342        signed char *p = (signed char *)file + *pos;
 343        char *s = line;
 344
 345        for (; *pos < size ; (*pos)++) {
 346                if (skip && isspace(*p)) {
 347                        p++;
 348                        continue;
 349                }
 350                skip = 0;
 351                if (*p != '\n' && (*pos < size)) {
 352                        len++;
 353                        *s++ = *p++;
 354                        if (len > 4095)
 355                                break; /* Too long, stop */
 356                } else {
 357                        /* End of string */
 358                        *s = '\0';
 359                        return line;
 360                }
 361        }
 362        /* End of buffer */
 363        return NULL;
 364}
 365
 366void release_file(void *file, unsigned long size)
 367{
 368        munmap(file, size);
 369}
 370
 371static int parse_elf(struct elf_info *info, const char *filename)
 372{
 373        unsigned int i;
 374        Elf_Ehdr *hdr;
 375        Elf_Shdr *sechdrs;
 376        Elf_Sym  *sym;
 377        const char *secstrings;
 378        unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 379
 380        hdr = grab_file(filename, &info->size);
 381        if (!hdr) {
 382                perror(filename);
 383                exit(1);
 384        }
 385        info->hdr = hdr;
 386        if (info->size < sizeof(*hdr)) {
 387                /* file too small, assume this is an empty .o file */
 388                return 0;
 389        }
 390        /* Is this a valid ELF file? */
 391        if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 392            (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 393            (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 394            (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 395                /* Not an ELF file - silently ignore it */
 396                return 0;
 397        }
 398        /* Fix endianness in ELF header */
 399        hdr->e_type      = TO_NATIVE(hdr->e_type);
 400        hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 401        hdr->e_version   = TO_NATIVE(hdr->e_version);
 402        hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 403        hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 404        hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 405        hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 406        hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 407        hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 408        hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 409        hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 410        hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 411        hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 412        sechdrs = (void *)hdr + hdr->e_shoff;
 413        info->sechdrs = sechdrs;
 414
 415        /* Check if file offset is correct */
 416        if (hdr->e_shoff > info->size) {
 417                fatal("section header offset=%lu in file '%s' is bigger than "
 418                      "filesize=%lu\n", (unsigned long)hdr->e_shoff,
 419                      filename, info->size);
 420                return 0;
 421        }
 422
 423        if (hdr->e_shnum == 0) {
 424                /*
 425                 * There are more than 64k sections,
 426                 * read count from .sh_size.
 427                 * note: it doesn't need shndx2secindex()
 428                 */
 429                info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 430        }
 431        else {
 432                info->num_sections = hdr->e_shnum;
 433        }
 434        if (hdr->e_shstrndx == SHN_XINDEX) {
 435                info->secindex_strings =
 436                    shndx2secindex(TO_NATIVE(sechdrs[0].sh_link));
 437        }
 438        else {
 439                info->secindex_strings = hdr->e_shstrndx;
 440        }
 441
 442        /* Fix endianness in section headers */
 443        for (i = 0; i < info->num_sections; i++) {
 444                sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 445                sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 446                sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 447                sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 448                sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 449                sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 450                sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 451                sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 452                sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 453                sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 454        }
 455        /* Find symbol table. */
 456        secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 457        for (i = 1; i < info->num_sections; i++) {
 458                const char *secname;
 459                int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 460
 461                if (!nobits && sechdrs[i].sh_offset > info->size) {
 462                        fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
 463                              "sizeof(*hrd)=%zu\n", filename,
 464                              (unsigned long)sechdrs[i].sh_offset,
 465                              sizeof(*hdr));
 466                        return 0;
 467                }
 468                secname = secstrings + sechdrs[i].sh_name;
 469                if (strcmp(secname, ".modinfo") == 0) {
 470                        if (nobits)
 471                                fatal("%s has NOBITS .modinfo\n", filename);
 472                        info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 473                        info->modinfo_len = sechdrs[i].sh_size;
 474                } else if (strcmp(secname, "__ksymtab") == 0)
 475                        info->export_sec = i;
 476                else if (strcmp(secname, "__ksymtab_unused") == 0)
 477                        info->export_unused_sec = i;
 478                else if (strcmp(secname, "__ksymtab_gpl") == 0)
 479                        info->export_gpl_sec = i;
 480                else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 481                        info->export_unused_gpl_sec = i;
 482                else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
 483                        info->export_gpl_future_sec = i;
 484
 485                if (sechdrs[i].sh_type == SHT_SYMTAB) {
 486                        unsigned int sh_link_idx;
 487                        symtab_idx = i;
 488                        info->symtab_start = (void *)hdr +
 489                            sechdrs[i].sh_offset;
 490                        info->symtab_stop  = (void *)hdr +
 491                            sechdrs[i].sh_offset + sechdrs[i].sh_size;
 492                        sh_link_idx = shndx2secindex(sechdrs[i].sh_link);
 493                        info->strtab       = (void *)hdr +
 494                            sechdrs[sh_link_idx].sh_offset;
 495                }
 496
 497                /* 32bit section no. table? ("more than 64k sections") */
 498                if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 499                        symtab_shndx_idx = i;
 500                        info->symtab_shndx_start = (void *)hdr +
 501                            sechdrs[i].sh_offset;
 502                        info->symtab_shndx_stop  = (void *)hdr +
 503                            sechdrs[i].sh_offset + sechdrs[i].sh_size;
 504                }
 505        }
 506        if (!info->symtab_start)
 507                fatal("%s has no symtab?\n", filename);
 508
 509        /* Fix endianness in symbols */
 510        for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 511                sym->st_shndx = TO_NATIVE(sym->st_shndx);
 512                sym->st_name  = TO_NATIVE(sym->st_name);
 513                sym->st_value = TO_NATIVE(sym->st_value);
 514                sym->st_size  = TO_NATIVE(sym->st_size);
 515        }
 516
 517        if (symtab_shndx_idx != ~0U) {
 518                Elf32_Word *p;
 519                if (symtab_idx !=
 520                    shndx2secindex(sechdrs[symtab_shndx_idx].sh_link))
 521                        fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 522                              filename,
 523                              shndx2secindex(sechdrs[symtab_shndx_idx].sh_link),
 524                              symtab_idx);
 525                /* Fix endianness */
 526                for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 527                     p++)
 528                        *p = TO_NATIVE(*p);
 529        }
 530
 531        return 1;
 532}
 533
 534static void parse_elf_finish(struct elf_info *info)
 535{
 536        release_file(info->hdr, info->size);
 537}
 538
 539static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 540{
 541        /* ignore __this_module, it will be resolved shortly */
 542        if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
 543                return 1;
 544        /* ignore global offset table */
 545        if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 546                return 1;
 547        if (info->hdr->e_machine == EM_PPC)
 548                /* Special register function linked on all modules during final link of .ko */
 549                if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
 550                    strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
 551                    strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
 552                    strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
 553                        return 1;
 554        if (info->hdr->e_machine == EM_PPC64)
 555                /* Special register function linked on all modules during final link of .ko */
 556                if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
 557                    strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
 558                        return 1;
 559        /* Do not ignore this symbol */
 560        return 0;
 561}
 562
 563#define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
 564#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
 565
 566static void handle_modversions(struct module *mod, struct elf_info *info,
 567                               Elf_Sym *sym, const char *symname)
 568{
 569        unsigned int crc;
 570        enum export export = export_from_sec(info, get_secindex(info, sym));
 571
 572        switch (sym->st_shndx) {
 573        case SHN_COMMON:
 574                warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 575                break;
 576        case SHN_ABS:
 577                /* CRC'd symbol */
 578                if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
 579                        crc = (unsigned int) sym->st_value;
 580                        sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
 581                                        export);
 582                }
 583                break;
 584        case SHN_UNDEF:
 585                /* undefined symbol */
 586                if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 587                    ELF_ST_BIND(sym->st_info) != STB_WEAK)
 588                        break;
 589                if (ignore_undef_symbol(info, symname))
 590                        break;
 591/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
 592#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
 593/* add compatibility with older glibc */
 594#ifndef STT_SPARC_REGISTER
 595#define STT_SPARC_REGISTER STT_REGISTER
 596#endif
 597                if (info->hdr->e_machine == EM_SPARC ||
 598                    info->hdr->e_machine == EM_SPARCV9) {
 599                        /* Ignore register directives. */
 600                        if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 601                                break;
 602                        if (symname[0] == '.') {
 603                                char *munged = strdup(symname);
 604                                munged[0] = '_';
 605                                munged[1] = toupper(munged[1]);
 606                                symname = munged;
 607                        }
 608                }
 609#endif
 610
 611                if (memcmp(symname, MODULE_SYMBOL_PREFIX,
 612                           strlen(MODULE_SYMBOL_PREFIX)) == 0) {
 613                        mod->unres =
 614                          alloc_symbol(symname +
 615                                       strlen(MODULE_SYMBOL_PREFIX),
 616                                       ELF_ST_BIND(sym->st_info) == STB_WEAK,
 617                                       mod->unres);
 618                }
 619                break;
 620        default:
 621                /* All exported symbols */
 622                if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
 623                        sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
 624                                        export);
 625                }
 626                if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
 627                        mod->has_init = 1;
 628                if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
 629                        mod->has_cleanup = 1;
 630                break;
 631        }
 632}
 633
 634/**
 635 * Parse tag=value strings from .modinfo section
 636 **/
 637static char *next_string(char *string, unsigned long *secsize)
 638{
 639        /* Skip non-zero chars */
 640        while (string[0]) {
 641                string++;
 642                if ((*secsize)-- <= 1)
 643                        return NULL;
 644        }
 645
 646        /* Skip any zero padding. */
 647        while (!string[0]) {
 648                string++;
 649                if ((*secsize)-- <= 1)
 650                        return NULL;
 651        }
 652        return string;
 653}
 654
 655static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
 656                              const char *tag, char *info)
 657{
 658        char *p;
 659        unsigned int taglen = strlen(tag);
 660        unsigned long size = modinfo_len;
 661
 662        if (info) {
 663                size -= info - (char *)modinfo;
 664                modinfo = next_string(info, &size);
 665        }
 666
 667        for (p = modinfo; p; p = next_string(p, &size)) {
 668                if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 669                        return p + taglen + 1;
 670        }
 671        return NULL;
 672}
 673
 674static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
 675                         const char *tag)
 676
 677{
 678        return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
 679}
 680
 681/**
 682 * Test if string s ends in string sub
 683 * return 0 if match
 684 **/
 685static int strrcmp(const char *s, const char *sub)
 686{
 687        int slen, sublen;
 688
 689        if (!s || !sub)
 690                return 1;
 691
 692        slen = strlen(s);
 693        sublen = strlen(sub);
 694
 695        if ((slen == 0) || (sublen == 0))
 696                return 1;
 697
 698        if (sublen > slen)
 699                return 1;
 700
 701        return memcmp(s + slen - sublen, sub, sublen);
 702}
 703
 704static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 705{
 706        if (sym)
 707                return elf->strtab + sym->st_name;
 708        else
 709                return "(unknown)";
 710}
 711
 712static const char *sec_name(struct elf_info *elf, int secindex)
 713{
 714        Elf_Shdr *sechdrs = elf->sechdrs;
 715        return (void *)elf->hdr +
 716                elf->sechdrs[elf->secindex_strings].sh_offset +
 717                sechdrs[secindex].sh_name;
 718}
 719
 720static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
 721{
 722        return (void *)elf->hdr +
 723                elf->sechdrs[elf->secindex_strings].sh_offset +
 724                sechdr->sh_name;
 725}
 726
 727/* if sym is empty or point to a string
 728 * like ".[0-9]+" then return 1.
 729 * This is the optional prefix added by ld to some sections
 730 */
 731static int number_prefix(const char *sym)
 732{
 733        if (*sym++ == '\0')
 734                return 1;
 735        if (*sym != '.')
 736                return 0;
 737        do {
 738                char c = *sym++;
 739                if (c < '0' || c > '9')
 740                        return 0;
 741        } while (*sym);
 742        return 1;
 743}
 744
 745/* The pattern is an array of simple patterns.
 746 * "foo" will match an exact string equal to "foo"
 747 * "*foo" will match a string that ends with "foo"
 748 * "foo*" will match a string that begins with "foo"
 749 * "foo$" will match a string equal to "foo" or "foo.1"
 750 *   where the '1' can be any number including several digits.
 751 *   The $ syntax is for sections where ld append a dot number
 752 *   to make section name unique.
 753 */
 754static int match(const char *sym, const char * const pat[])
 755{
 756        const char *p;
 757        while (*pat) {
 758                p = *pat++;
 759                const char *endp = p + strlen(p) - 1;
 760
 761                /* "*foo" */
 762                if (*p == '*') {
 763                        if (strrcmp(sym, p + 1) == 0)
 764                                return 1;
 765                }
 766                /* "foo*" */
 767                else if (*endp == '*') {
 768                        if (strncmp(sym, p, strlen(p) - 1) == 0)
 769                                return 1;
 770                }
 771                /* "foo$" */
 772                else if (*endp == '$') {
 773                        if (strncmp(sym, p, strlen(p) - 1) == 0) {
 774                                if (number_prefix(sym + strlen(p) - 1))
 775                                        return 1;
 776                        }
 777                }
 778                /* no wildcards */
 779                else {
 780                        if (strcmp(p, sym) == 0)
 781                                return 1;
 782                }
 783        }
 784        /* no match */
 785        return 0;
 786}
 787
 788/* sections that we do not want to do full section mismatch check on */
 789static const char *section_white_list[] =
 790{
 791        ".comment*",
 792        ".debug*",
 793        ".zdebug*",             /* Compressed debug sections. */
 794        ".GCC-command-line",    /* mn10300 */
 795        ".mdebug*",        /* alpha, score, mips etc. */
 796        ".pdr",            /* alpha, score, mips etc. */
 797        ".stab*",
 798        ".note*",
 799        ".got*",
 800        ".toc*",
 801        NULL
 802};
 803
 804/*
 805 * This is used to find sections missing the SHF_ALLOC flag.
 806 * The cause of this is often a section specified in assembler
 807 * without "ax" / "aw".
 808 */
 809static void check_section(const char *modname, struct elf_info *elf,
 810                          Elf_Shdr *sechdr)
 811{
 812        const char *sec = sech_name(elf, sechdr);
 813
 814        if (sechdr->sh_type == SHT_PROGBITS &&
 815            !(sechdr->sh_flags & SHF_ALLOC) &&
 816            !match(sec, section_white_list)) {
 817                warn("%s (%s): unexpected non-allocatable section.\n"
 818                     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 819                     "Note that for example <linux/init.h> contains\n"
 820                     "section definitions for use in .S files.\n\n",
 821                     modname, sec);
 822        }
 823}
 824
 825
 826
 827#define ALL_INIT_DATA_SECTIONS \
 828        ".init.setup$", ".init.rodata$", \
 829        ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$" \
 830        ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
 831#define ALL_EXIT_DATA_SECTIONS \
 832        ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
 833
 834#define ALL_INIT_TEXT_SECTIONS \
 835        ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
 836#define ALL_EXIT_TEXT_SECTIONS \
 837        ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
 838
 839#define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
 840        MEM_INIT_SECTIONS
 841#define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
 842        MEM_EXIT_SECTIONS
 843
 844#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 845#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 846
 847#define DATA_SECTIONS ".data$", ".data.rel$"
 848#define TEXT_SECTIONS ".text$"
 849
 850#define INIT_SECTIONS      ".init.*"
 851#define DEV_INIT_SECTIONS  ".devinit.*"
 852#define CPU_INIT_SECTIONS  ".cpuinit.*"
 853#define MEM_INIT_SECTIONS  ".meminit.*"
 854
 855#define EXIT_SECTIONS      ".exit.*"
 856#define DEV_EXIT_SECTIONS  ".devexit.*"
 857#define CPU_EXIT_SECTIONS  ".cpuexit.*"
 858#define MEM_EXIT_SECTIONS  ".memexit.*"
 859
 860/* init data sections */
 861static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
 862
 863/* all init sections */
 864static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
 865
 866/* All init and exit sections (code + data) */
 867static const char *init_exit_sections[] =
 868        {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 869
 870/* data section */
 871static const char *data_sections[] = { DATA_SECTIONS, NULL };
 872
 873
 874/* symbols in .data that may refer to init/exit sections */
 875#define DEFAULT_SYMBOL_WHITE_LIST                                       \
 876        "*driver",                                                      \
 877        "*_template", /* scsi uses *_template a lot */                  \
 878        "*_timer",    /* arm uses ops structures named _timer a lot */  \
 879        "*_sht",      /* scsi also used *_sht to some extent */         \
 880        "*_ops",                                                        \
 881        "*_probe",                                                      \
 882        "*_probe_one",                                                  \
 883        "*_console"
 884
 885static const char *head_sections[] = { ".head.text*", NULL };
 886static const char *linker_symbols[] =
 887        { "__init_begin", "_sinittext", "_einittext", NULL };
 888
 889enum mismatch {
 890        TEXT_TO_ANY_INIT,
 891        DATA_TO_ANY_INIT,
 892        TEXT_TO_ANY_EXIT,
 893        DATA_TO_ANY_EXIT,
 894        XXXINIT_TO_SOME_INIT,
 895        XXXEXIT_TO_SOME_EXIT,
 896        ANY_INIT_TO_ANY_EXIT,
 897        ANY_EXIT_TO_ANY_INIT,
 898        EXPORT_TO_INIT_EXIT,
 899};
 900
 901struct sectioncheck {
 902        const char *fromsec[20];
 903        const char *tosec[20];
 904        enum mismatch mismatch;
 905        const char *symbol_white_list[20];
 906};
 907
 908const struct sectioncheck sectioncheck[] = {
 909/* Do not reference init/exit code/data from
 910 * normal code and data
 911 */
 912{
 913        .fromsec = { TEXT_SECTIONS, NULL },
 914        .tosec   = { ALL_INIT_SECTIONS, NULL },
 915        .mismatch = TEXT_TO_ANY_INIT,
 916        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 917},
 918{
 919        .fromsec = { DATA_SECTIONS, NULL },
 920        .tosec   = { ALL_XXXINIT_SECTIONS, NULL },
 921        .mismatch = DATA_TO_ANY_INIT,
 922        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 923},
 924{
 925        .fromsec = { DATA_SECTIONS, NULL },
 926        .tosec   = { INIT_SECTIONS, NULL },
 927        .mismatch = DATA_TO_ANY_INIT,
 928        .symbol_white_list = {
 929                "*_template", "*_timer", "*_sht", "*_ops",
 930                "*_probe", "*_probe_one", "*_console", NULL
 931        },
 932},
 933{
 934        .fromsec = { TEXT_SECTIONS, NULL },
 935        .tosec   = { ALL_EXIT_SECTIONS, NULL },
 936        .mismatch = TEXT_TO_ANY_EXIT,
 937        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 938},
 939{
 940        .fromsec = { DATA_SECTIONS, NULL },
 941        .tosec   = { ALL_EXIT_SECTIONS, NULL },
 942        .mismatch = DATA_TO_ANY_EXIT,
 943        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 944},
 945/* Do not reference init code/data from devinit/cpuinit/meminit code/data */
 946{
 947        .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
 948        .tosec   = { INIT_SECTIONS, NULL },
 949        .mismatch = XXXINIT_TO_SOME_INIT,
 950        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 951},
 952/* Do not reference cpuinit code/data from meminit code/data */
 953{
 954        .fromsec = { MEM_INIT_SECTIONS, NULL },
 955        .tosec   = { CPU_INIT_SECTIONS, NULL },
 956        .mismatch = XXXINIT_TO_SOME_INIT,
 957        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 958},
 959/* Do not reference meminit code/data from cpuinit code/data */
 960{
 961        .fromsec = { CPU_INIT_SECTIONS, NULL },
 962        .tosec   = { MEM_INIT_SECTIONS, NULL },
 963        .mismatch = XXXINIT_TO_SOME_INIT,
 964        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 965},
 966/* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
 967{
 968        .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
 969        .tosec   = { EXIT_SECTIONS, NULL },
 970        .mismatch = XXXEXIT_TO_SOME_EXIT,
 971        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 972},
 973/* Do not reference cpuexit code/data from memexit code/data */
 974{
 975        .fromsec = { MEM_EXIT_SECTIONS, NULL },
 976        .tosec   = { CPU_EXIT_SECTIONS, NULL },
 977        .mismatch = XXXEXIT_TO_SOME_EXIT,
 978        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 979},
 980/* Do not reference memexit code/data from cpuexit code/data */
 981{
 982        .fromsec = { CPU_EXIT_SECTIONS, NULL },
 983        .tosec   = { MEM_EXIT_SECTIONS, NULL },
 984        .mismatch = XXXEXIT_TO_SOME_EXIT,
 985        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 986},
 987/* Do not use exit code/data from init code */
 988{
 989        .fromsec = { ALL_INIT_SECTIONS, NULL },
 990        .tosec   = { ALL_EXIT_SECTIONS, NULL },
 991        .mismatch = ANY_INIT_TO_ANY_EXIT,
 992        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
 993},
 994/* Do not use init code/data from exit code */
 995{
 996        .fromsec = { ALL_EXIT_SECTIONS, NULL },
 997        .tosec   = { ALL_INIT_SECTIONS, NULL },
 998        .mismatch = ANY_EXIT_TO_ANY_INIT,
 999        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1000},
1001/* Do not export init/exit functions or data */
1002{
1003        .fromsec = { "__ksymtab*", NULL },
1004        .tosec   = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1005        .mismatch = EXPORT_TO_INIT_EXIT,
1006        .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1007}
1008};
1009
1010static const struct sectioncheck *section_mismatch(
1011                const char *fromsec, const char *tosec)
1012{
1013        int i;
1014        int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1015        const struct sectioncheck *check = &sectioncheck[0];
1016
1017        for (i = 0; i < elems; i++) {
1018                if (match(fromsec, check->fromsec) &&
1019                    match(tosec, check->tosec))
1020                        return check;
1021                check++;
1022        }
1023        return NULL;
1024}
1025
1026/**
1027 * Whitelist to allow certain references to pass with no warning.
1028 *
1029 * Pattern 1:
1030 *   If a module parameter is declared __initdata and permissions=0
1031 *   then this is legal despite the warning generated.
1032 *   We cannot see value of permissions here, so just ignore
1033 *   this pattern.
1034 *   The pattern is identified by:
1035 *   tosec   = .init.data
1036 *   fromsec = .data*
1037 *   atsym   =__param*
1038 *
1039 * Pattern 1a:
1040 *   module_param_call() ops can refer to __init set function if permissions=0
1041 *   The pattern is identified by:
1042 *   tosec   = .init.text
1043 *   fromsec = .data*
1044 *   atsym   = __param_ops_*
1045 *
1046 * Pattern 2:
1047 *   Many drivers utilise a *driver container with references to
1048 *   add, remove, probe functions etc.
1049 *   These functions may often be marked __devinit and we do not want to
1050 *   warn here.
1051 *   the pattern is identified by:
1052 *   tosec   = init or exit section
1053 *   fromsec = data section
1054 *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1055 *           *probe_one, *_console, *_timer
1056 *
1057 * Pattern 3:
1058 *   Whitelist all references from .head.text to any init section
1059 *
1060 * Pattern 4:
1061 *   Some symbols belong to init section but still it is ok to reference
1062 *   these from non-init sections as these symbols don't have any memory
1063 *   allocated for them and symbol address and value are same. So even
1064 *   if init section is freed, its ok to reference those symbols.
1065 *   For ex. symbols marking the init section boundaries.
1066 *   This pattern is identified by
1067 *   refsymname = __init_begin, _sinittext, _einittext
1068 *
1069 **/
1070static int secref_whitelist(const struct sectioncheck *mismatch,
1071                            const char *fromsec, const char *fromsym,
1072                            const char *tosec, const char *tosym)
1073{
1074        /* Check for pattern 1 */
1075        if (match(tosec, init_data_sections) &&
1076            match(fromsec, data_sections) &&
1077            (strncmp(fromsym, "__param", strlen("__param")) == 0))
1078                return 0;
1079
1080        /* Check for pattern 1a */
1081        if (strcmp(tosec, ".init.text") == 0 &&
1082            match(fromsec, data_sections) &&
1083            (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1084                return 0;
1085
1086        /* Check for pattern 2 */
1087        if (match(tosec, init_exit_sections) &&
1088            match(fromsec, data_sections) &&
1089            match(fromsym, mismatch->symbol_white_list))
1090                return 0;
1091
1092        /* Check for pattern 3 */
1093        if (match(fromsec, head_sections) &&
1094            match(tosec, init_sections))
1095                return 0;
1096
1097        /* Check for pattern 4 */
1098        if (match(tosym, linker_symbols))
1099                return 0;
1100
1101        return 1;
1102}
1103
1104/**
1105 * Find symbol based on relocation record info.
1106 * In some cases the symbol supplied is a valid symbol so
1107 * return refsym. If st_name != 0 we assume this is a valid symbol.
1108 * In other cases the symbol needs to be looked up in the symbol table
1109 * based on section and address.
1110 *  **/
1111static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1112                                Elf_Sym *relsym)
1113{
1114        Elf_Sym *sym;
1115        Elf_Sym *near = NULL;
1116        Elf64_Sword distance = 20;
1117        Elf64_Sword d;
1118        unsigned int relsym_secindex;
1119
1120        if (relsym->st_name != 0)
1121                return relsym;
1122
1123        relsym_secindex = get_secindex(elf, relsym);
1124        for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1125                if (get_secindex(elf, sym) != relsym_secindex)
1126                        continue;
1127                if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1128                        continue;
1129                if (sym->st_value == addr)
1130                        return sym;
1131                /* Find a symbol nearby - addr are maybe negative */
1132                d = sym->st_value - addr;
1133                if (d < 0)
1134                        d = addr - sym->st_value;
1135                if (d < distance) {
1136                        distance = d;
1137                        near = sym;
1138                }
1139        }
1140        /* We need a close match */
1141        if (distance < 20)
1142                return near;
1143        else
1144                return NULL;
1145}
1146
1147static inline int is_arm_mapping_symbol(const char *str)
1148{
1149        return str[0] == '$' && strchr("atd", str[1])
1150               && (str[2] == '\0' || str[2] == '.');
1151}
1152
1153/*
1154 * If there's no name there, ignore it; likewise, ignore it if it's
1155 * one of the magic symbols emitted used by current ARM tools.
1156 *
1157 * Otherwise if find_symbols_between() returns those symbols, they'll
1158 * fail the whitelist tests and cause lots of false alarms ... fixable
1159 * only by merging __exit and __init sections into __text, bloating
1160 * the kernel (which is especially evil on embedded platforms).
1161 */
1162static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1163{
1164        const char *name = elf->strtab + sym->st_name;
1165
1166        if (!name || !strlen(name))
1167                return 0;
1168        return !is_arm_mapping_symbol(name);
1169}
1170
1171/*
1172 * Find symbols before or equal addr and after addr - in the section sec.
1173 * If we find two symbols with equal offset prefer one with a valid name.
1174 * The ELF format may have a better way to detect what type of symbol
1175 * it is, but this works for now.
1176 **/
1177static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1178                                 const char *sec)
1179{
1180        Elf_Sym *sym;
1181        Elf_Sym *near = NULL;
1182        Elf_Addr distance = ~0;
1183
1184        for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1185                const char *symsec;
1186
1187                if (is_shndx_special(sym->st_shndx))
1188                        continue;
1189                symsec = sec_name(elf, get_secindex(elf, sym));
1190                if (strcmp(symsec, sec) != 0)
1191                        continue;
1192                if (!is_valid_name(elf, sym))
1193                        continue;
1194                if (sym->st_value <= addr) {
1195                        if ((addr - sym->st_value) < distance) {
1196                                distance = addr - sym->st_value;
1197                                near = sym;
1198                        } else if ((addr - sym->st_value) == distance) {
1199                                near = sym;
1200                        }
1201                }
1202        }
1203        return near;
1204}
1205
1206/*
1207 * Convert a section name to the function/data attribute
1208 * .init.text => __init
1209 * .cpuinit.data => __cpudata
1210 * .memexitconst => __memconst
1211 * etc.
1212 *
1213 * The memory of returned value has been allocated on a heap. The user of this
1214 * method should free it after usage.
1215*/
1216static char *sec2annotation(const char *s)
1217{
1218        if (match(s, init_exit_sections)) {
1219                char *p = malloc(20);
1220                char *r = p;
1221
1222                *p++ = '_';
1223                *p++ = '_';
1224                if (*s == '.')
1225                        s++;
1226                while (*s && *s != '.')
1227                        *p++ = *s++;
1228                *p = '\0';
1229                if (*s == '.')
1230                        s++;
1231                if (strstr(s, "rodata") != NULL)
1232                        strcat(p, "const ");
1233                else if (strstr(s, "data") != NULL)
1234                        strcat(p, "data ");
1235                else
1236                        strcat(p, " ");
1237                return r;
1238        } else {
1239                return strdup("");
1240        }
1241}
1242
1243static int is_function(Elf_Sym *sym)
1244{
1245        if (sym)
1246                return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1247        else
1248                return -1;
1249}
1250
1251static void print_section_list(const char * const list[20])
1252{
1253        const char *const *s = list;
1254
1255        while (*s) {
1256                fprintf(stderr, "%s", *s);
1257                s++;
1258                if (*s)
1259                        fprintf(stderr, ", ");
1260        }
1261        fprintf(stderr, "\n");
1262}
1263
1264/*
1265 * Print a warning about a section mismatch.
1266 * Try to find symbols near it so user can find it.
1267 * Check whitelist before warning - it may be a false positive.
1268 */
1269static void report_sec_mismatch(const char *modname,
1270                                const struct sectioncheck *mismatch,
1271                                const char *fromsec,
1272                                unsigned long long fromaddr,
1273                                const char *fromsym,
1274                                int from_is_func,
1275                                const char *tosec, const char *tosym,
1276                                int to_is_func)
1277{
1278        const char *from, *from_p;
1279        const char *to, *to_p;
1280        char *prl_from;
1281        char *prl_to;
1282
1283        switch (from_is_func) {
1284        case 0: from = "variable"; from_p = "";   break;
1285        case 1: from = "function"; from_p = "()"; break;
1286        default: from = "(unknown reference)"; from_p = ""; break;
1287        }
1288        switch (to_is_func) {
1289        case 0: to = "variable"; to_p = "";   break;
1290        case 1: to = "function"; to_p = "()"; break;
1291        default: to = "(unknown reference)"; to_p = ""; break;
1292        }
1293
1294        sec_mismatch_count++;
1295        if (!sec_mismatch_verbose)
1296                return;
1297
1298        warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1299             "to the %s %s:%s%s\n",
1300             modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1301             tosym, to_p);
1302
1303        switch (mismatch->mismatch) {
1304        case TEXT_TO_ANY_INIT:
1305                prl_from = sec2annotation(fromsec);
1306                prl_to = sec2annotation(tosec);
1307                fprintf(stderr,
1308                "The function %s%s() references\n"
1309                "the %s %s%s%s.\n"
1310                "This is often because %s lacks a %s\n"
1311                "annotation or the annotation of %s is wrong.\n",
1312                prl_from, fromsym,
1313                to, prl_to, tosym, to_p,
1314                fromsym, prl_to, tosym);
1315                free(prl_from);
1316                free(prl_to);
1317                break;
1318        case DATA_TO_ANY_INIT: {
1319                prl_to = sec2annotation(tosec);
1320                fprintf(stderr,
1321                "The variable %s references\n"
1322                "the %s %s%s%s\n"
1323                "If the reference is valid then annotate the\n"
1324                "variable with __init* or __refdata (see linux/init.h) "
1325                "or name the variable:\n",
1326                fromsym, to, prl_to, tosym, to_p);
1327                print_section_list(mismatch->symbol_white_list);
1328                free(prl_to);
1329                break;
1330        }
1331        case TEXT_TO_ANY_EXIT:
1332                prl_to = sec2annotation(tosec);
1333                fprintf(stderr,
1334                "The function %s() references a %s in an exit section.\n"
1335                "Often the %s %s%s has valid usage outside the exit section\n"
1336                "and the fix is to remove the %sannotation of %s.\n",
1337                fromsym, to, to, tosym, to_p, prl_to, tosym);
1338                free(prl_to);
1339                break;
1340        case DATA_TO_ANY_EXIT: {
1341                prl_to = sec2annotation(tosec);
1342                fprintf(stderr,
1343                "The variable %s references\n"
1344                "the %s %s%s%s\n"
1345                "If the reference is valid then annotate the\n"
1346                "variable with __exit* (see linux/init.h) or "
1347                "name the variable:\n",
1348                fromsym, to, prl_to, tosym, to_p);
1349                print_section_list(mismatch->symbol_white_list);
1350                free(prl_to);
1351                break;
1352        }
1353        case XXXINIT_TO_SOME_INIT:
1354        case XXXEXIT_TO_SOME_EXIT:
1355                prl_from = sec2annotation(fromsec);
1356                prl_to = sec2annotation(tosec);
1357                fprintf(stderr,
1358                "The %s %s%s%s references\n"
1359                "a %s %s%s%s.\n"
1360                "If %s is only used by %s then\n"
1361                "annotate %s with a matching annotation.\n",
1362                from, prl_from, fromsym, from_p,
1363                to, prl_to, tosym, to_p,
1364                tosym, fromsym, tosym);
1365                free(prl_from);
1366                free(prl_to);
1367                break;
1368        case ANY_INIT_TO_ANY_EXIT:
1369                prl_from = sec2annotation(fromsec);
1370                prl_to = sec2annotation(tosec);
1371                fprintf(stderr,
1372                "The %s %s%s%s references\n"
1373                "a %s %s%s%s.\n"
1374                "This is often seen when error handling "
1375                "in the init function\n"
1376                "uses functionality in the exit path.\n"
1377                "The fix is often to remove the %sannotation of\n"
1378                "%s%s so it may be used outside an exit section.\n",
1379                from, prl_from, fromsym, from_p,
1380                to, prl_to, tosym, to_p,
1381                prl_to, tosym, to_p);
1382                free(prl_from);
1383                free(prl_to);
1384                break;
1385        case ANY_EXIT_TO_ANY_INIT:
1386                prl_from = sec2annotation(fromsec);
1387                prl_to = sec2annotation(tosec);
1388                fprintf(stderr,
1389                "The %s %s%s%s references\n"
1390                "a %s %s%s%s.\n"
1391                "This is often seen when error handling "
1392                "in the exit function\n"
1393                "uses functionality in the init path.\n"
1394                "The fix is often to remove the %sannotation of\n"
1395                "%s%s so it may be used outside an init section.\n",
1396                from, prl_from, fromsym, from_p,
1397                to, prl_to, tosym, to_p,
1398                prl_to, tosym, to_p);
1399                free(prl_from);
1400                free(prl_to);
1401                break;
1402        case EXPORT_TO_INIT_EXIT:
1403                prl_to = sec2annotation(tosec);
1404                fprintf(stderr,
1405                "The symbol %s is exported and annotated %s\n"
1406                "Fix this by removing the %sannotation of %s "
1407                "or drop the export.\n",
1408                tosym, prl_to, prl_to, tosym);
1409                free(prl_to);
1410                break;
1411        }
1412        fprintf(stderr, "\n");
1413}
1414
1415static void check_section_mismatch(const char *modname, struct elf_info *elf,
1416                                   Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1417{
1418        const char *tosec;
1419        const struct sectioncheck *mismatch;
1420
1421        tosec = sec_name(elf, get_secindex(elf, sym));
1422        mismatch = section_mismatch(fromsec, tosec);
1423        if (mismatch) {
1424                Elf_Sym *to;
1425                Elf_Sym *from;
1426                const char *tosym;
1427                const char *fromsym;
1428
1429                from = find_elf_symbol2(elf, r->r_offset, fromsec);
1430                fromsym = sym_name(elf, from);
1431                to = find_elf_symbol(elf, r->r_addend, sym);
1432                tosym = sym_name(elf, to);
1433
1434                /* check whitelist - we may ignore it */
1435                if (secref_whitelist(mismatch,
1436                                        fromsec, fromsym, tosec, tosym)) {
1437                        report_sec_mismatch(modname, mismatch,
1438                           fromsec, r->r_offset, fromsym,
1439                           is_function(from), tosec, tosym,
1440                           is_function(to));
1441                }
1442        }
1443}
1444
1445static unsigned int *reloc_location(struct elf_info *elf,
1446                                    Elf_Shdr *sechdr, Elf_Rela *r)
1447{
1448        Elf_Shdr *sechdrs = elf->sechdrs;
1449        int section = shndx2secindex(sechdr->sh_info);
1450
1451        return (void *)elf->hdr + sechdrs[section].sh_offset +
1452                r->r_offset;
1453}
1454
1455static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1456{
1457        unsigned int r_typ = ELF_R_TYPE(r->r_info);
1458        unsigned int *location = reloc_location(elf, sechdr, r);
1459
1460        switch (r_typ) {
1461        case R_386_32:
1462                r->r_addend = TO_NATIVE(*location);
1463                break;
1464        case R_386_PC32:
1465                r->r_addend = TO_NATIVE(*location) + 4;
1466                /* For CONFIG_RELOCATABLE=y */
1467                if (elf->hdr->e_type == ET_EXEC)
1468                        r->r_addend += r->r_offset;
1469                break;
1470        }
1471        return 0;
1472}
1473
1474static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1475{
1476        unsigned int r_typ = ELF_R_TYPE(r->r_info);
1477
1478        switch (r_typ) {
1479        case R_ARM_ABS32:
1480                /* From ARM ABI: (S + A) | T */
1481                r->r_addend = (int)(long)
1482                              (elf->symtab_start + ELF_R_SYM(r->r_info));
1483                break;
1484        case R_ARM_PC24:
1485                /* From ARM ABI: ((S + A) | T) - P */
1486                r->r_addend = (int)(long)(elf->hdr +
1487                              sechdr->sh_offset +
1488                              (r->r_offset - sechdr->sh_addr));
1489                break;
1490        default:
1491                return 1;
1492        }
1493        return 0;
1494}
1495
1496static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1497{
1498        unsigned int r_typ = ELF_R_TYPE(r->r_info);
1499        unsigned int *location = reloc_location(elf, sechdr, r);
1500        unsigned int inst;
1501
1502        if (r_typ == R_MIPS_HI16)
1503                return 1;       /* skip this */
1504        inst = TO_NATIVE(*location);
1505        switch (r_typ) {
1506        case R_MIPS_LO16:
1507                r->r_addend = inst & 0xffff;
1508                break;
1509        case R_MIPS_26:
1510                r->r_addend = (inst & 0x03ffffff) << 2;
1511                break;
1512        case R_MIPS_32:
1513                r->r_addend = inst;
1514                break;
1515        }
1516        return 0;
1517}
1518
1519static void section_rela(const char *modname, struct elf_info *elf,
1520                         Elf_Shdr *sechdr)
1521{
1522        Elf_Sym  *sym;
1523        Elf_Rela *rela;
1524        Elf_Rela r;
1525        unsigned int r_sym;
1526        const char *fromsec;
1527
1528        Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1529        Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1530
1531        fromsec = sech_name(elf, sechdr);
1532        fromsec += strlen(".rela");
1533        /* if from section (name) is know good then skip it */
1534        if (match(fromsec, section_white_list))
1535                return;
1536
1537        for (rela = start; rela < stop; rela++) {
1538                r.r_offset = TO_NATIVE(rela->r_offset);
1539#if KERNEL_ELFCLASS == ELFCLASS64
1540                if (elf->hdr->e_machine == EM_MIPS) {
1541                        unsigned int r_typ;
1542                        r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1543                        r_sym = TO_NATIVE(r_sym);
1544                        r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1545                        r.r_info = ELF64_R_INFO(r_sym, r_typ);
1546                } else {
1547                        r.r_info = TO_NATIVE(rela->r_info);
1548                        r_sym = ELF_R_SYM(r.r_info);
1549                }
1550#else
1551                r.r_info = TO_NATIVE(rela->r_info);
1552                r_sym = ELF_R_SYM(r.r_info);
1553#endif
1554                r.r_addend = TO_NATIVE(rela->r_addend);
1555                sym = elf->symtab_start + r_sym;
1556                /* Skip special sections */
1557                if (is_shndx_special(sym->st_shndx))
1558                        continue;
1559                check_section_mismatch(modname, elf, &r, sym, fromsec);
1560        }
1561}
1562
1563static void section_rel(const char *modname, struct elf_info *elf,
1564                        Elf_Shdr *sechdr)
1565{
1566        Elf_Sym *sym;
1567        Elf_Rel *rel;
1568        Elf_Rela r;
1569        unsigned int r_sym;
1570        const char *fromsec;
1571
1572        Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1573        Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1574
1575        fromsec = sech_name(elf, sechdr);
1576        fromsec += strlen(".rel");
1577        /* if from section (name) is know good then skip it */
1578        if (match(fromsec, section_white_list))
1579                return;
1580
1581        for (rel = start; rel < stop; rel++) {
1582                r.r_offset = TO_NATIVE(rel->r_offset);
1583#if KERNEL_ELFCLASS == ELFCLASS64
1584                if (elf->hdr->e_machine == EM_MIPS) {
1585                        unsigned int r_typ;
1586                        r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1587                        r_sym = TO_NATIVE(r_sym);
1588                        r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1589                        r.r_info = ELF64_R_INFO(r_sym, r_typ);
1590                } else {
1591                        r.r_info = TO_NATIVE(rel->r_info);
1592                        r_sym = ELF_R_SYM(r.r_info);
1593                }
1594#else
1595                r.r_info = TO_NATIVE(rel->r_info);
1596                r_sym = ELF_R_SYM(r.r_info);
1597#endif
1598                r.r_addend = 0;
1599                switch (elf->hdr->e_machine) {
1600                case EM_386:
1601                        if (addend_386_rel(elf, sechdr, &r))
1602                                continue;
1603                        break;
1604                case EM_ARM:
1605                        if (addend_arm_rel(elf, sechdr, &r))
1606                                continue;
1607                        break;
1608                case EM_MIPS:
1609                        if (addend_mips_rel(elf, sechdr, &r))
1610                                continue;
1611                        break;
1612                }
1613                sym = elf->symtab_start + r_sym;
1614                /* Skip special sections */
1615                if (is_shndx_special(sym->st_shndx))
1616                        continue;
1617                check_section_mismatch(modname, elf, &r, sym, fromsec);
1618        }
1619}
1620
1621/**
1622 * A module includes a number of sections that are discarded
1623 * either when loaded or when used as built-in.
1624 * For loaded modules all functions marked __init and all data
1625 * marked __initdata will be discarded when the module has been initialized.
1626 * Likewise for modules used built-in the sections marked __exit
1627 * are discarded because __exit marked function are supposed to be called
1628 * only when a module is unloaded which never happens for built-in modules.
1629 * The check_sec_ref() function traverses all relocation records
1630 * to find all references to a section that reference a section that will
1631 * be discarded and warns about it.
1632 **/
1633static void check_sec_ref(struct module *mod, const char *modname,
1634                          struct elf_info *elf)
1635{
1636        int i;
1637        Elf_Shdr *sechdrs = elf->sechdrs;
1638
1639        /* Walk through all sections */
1640        for (i = 0; i < elf->num_sections; i++) {
1641                check_section(modname, elf, &elf->sechdrs[i]);
1642                /* We want to process only relocation sections and not .init */
1643                if (sechdrs[i].sh_type == SHT_RELA)
1644                        section_rela(modname, elf, &elf->sechdrs[i]);
1645                else if (sechdrs[i].sh_type == SHT_REL)
1646                        section_rel(modname, elf, &elf->sechdrs[i]);
1647        }
1648}
1649
1650static void read_symbols(char *modname)
1651{
1652        const char *symname;
1653        char *version;
1654        char *license;
1655        struct module *mod;
1656        struct elf_info info = { };
1657        Elf_Sym *sym;
1658
1659        if (!parse_elf(&info, modname))
1660                return;
1661
1662        mod = new_module(modname);
1663
1664        /* When there's no vmlinux, don't print warnings about
1665         * unresolved symbols (since there'll be too many ;) */
1666        if (is_vmlinux(modname)) {
1667                have_vmlinux = 1;
1668                mod->skip = 1;
1669        }
1670
1671        license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1672        if (info.modinfo && !license && !is_vmlinux(modname))
1673                warn("modpost: missing MODULE_LICENSE() in %s\n"
1674                     "see include/linux/module.h for "
1675                     "more information\n", modname);
1676        while (license) {
1677                if (license_is_gpl_compatible(license))
1678                        mod->gpl_compatible = 1;
1679                else {
1680                        mod->gpl_compatible = 0;
1681                        break;
1682                }
1683                license = get_next_modinfo(info.modinfo, info.modinfo_len,
1684                                           "license", license);
1685        }
1686
1687        for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1688                symname = info.strtab + sym->st_name;
1689
1690                handle_modversions(mod, &info, sym, symname);
1691                handle_moddevtable(mod, &info, sym, symname);
1692        }
1693        if (!is_vmlinux(modname) ||
1694             (is_vmlinux(modname) && vmlinux_section_warnings))
1695                check_sec_ref(mod, modname, &info);
1696
1697        version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1698        if (version)
1699                maybe_frob_rcs_version(modname, version, info.modinfo,
1700                                       version - (char *)info.hdr);
1701        if (version || (all_versions && !is_vmlinux(modname)))
1702                get_src_version(modname, mod->srcversion,
1703                                sizeof(mod->srcversion)-1);
1704
1705        parse_elf_finish(&info);
1706
1707        /* Our trick to get versioning for module struct etc. - it's
1708         * never passed as an argument to an exported function, so
1709         * the automatic versioning doesn't pick it up, but it's really
1710         * important anyhow */
1711        if (modversions)
1712                mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1713}
1714
1715#define SZ 500
1716
1717/* We first write the generated file into memory using the
1718 * following helper, then compare to the file on disk and
1719 * only update the later if anything changed */
1720
1721void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1722                                                      const char *fmt, ...)
1723{
1724        char tmp[SZ];
1725        int len;
1726        va_list ap;
1727
1728        va_start(ap, fmt);
1729        len = vsnprintf(tmp, SZ, fmt, ap);
1730        buf_write(buf, tmp, len);
1731        va_end(ap);
1732}
1733
1734void buf_write(struct buffer *buf, const char *s, int len)
1735{
1736        if (buf->size - buf->pos < len) {
1737                buf->size += len + SZ;
1738                buf->p = realloc(buf->p, buf->size);
1739        }
1740        strncpy(buf->p + buf->pos, s, len);
1741        buf->pos += len;
1742}
1743
1744static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1745{
1746        const char *e = is_vmlinux(m) ?"":".ko";
1747
1748        switch (exp) {
1749        case export_gpl:
1750                fatal("modpost: GPL-incompatible module %s%s "
1751                      "uses GPL-only symbol '%s'\n", m, e, s);
1752                break;
1753        case export_unused_gpl:
1754                fatal("modpost: GPL-incompatible module %s%s "
1755                      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1756                break;
1757        case export_gpl_future:
1758                warn("modpost: GPL-incompatible module %s%s "
1759                      "uses future GPL-only symbol '%s'\n", m, e, s);
1760                break;
1761        case export_plain:
1762        case export_unused:
1763        case export_unknown:
1764                /* ignore */
1765                break;
1766        }
1767}
1768
1769static void check_for_unused(enum export exp, const char *m, const char *s)
1770{
1771        const char *e = is_vmlinux(m) ?"":".ko";
1772
1773        switch (exp) {
1774        case export_unused:
1775        case export_unused_gpl:
1776                warn("modpost: module %s%s "
1777                      "uses symbol '%s' marked UNUSED\n", m, e, s);
1778                break;
1779        default:
1780                /* ignore */
1781                break;
1782        }
1783}
1784
1785static void check_exports(struct module *mod)
1786{
1787        struct symbol *s, *exp;
1788
1789        for (s = mod->unres; s; s = s->next) {
1790                const char *basename;
1791                exp = find_symbol(s->name);
1792                if (!exp || exp->module == mod)
1793                        continue;
1794                basename = strrchr(mod->name, '/');
1795                if (basename)
1796                        basename++;
1797                else
1798                        basename = mod->name;
1799                if (!mod->gpl_compatible)
1800                        check_for_gpl_usage(exp->export, basename, exp->name);
1801                check_for_unused(exp->export, basename, exp->name);
1802        }
1803}
1804
1805/**
1806 * Header for the generated file
1807 **/
1808static void add_header(struct buffer *b, struct module *mod)
1809{
1810        buf_printf(b, "#include <linux/module.h>\n");
1811        buf_printf(b, "#include <linux/vermagic.h>\n");
1812        buf_printf(b, "#include <linux/compiler.h>\n");
1813        buf_printf(b, "\n");
1814        buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1815        buf_printf(b, "\n");
1816        buf_printf(b, "struct module __this_module\n");
1817        buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1818        buf_printf(b, " .name = KBUILD_MODNAME,\n");
1819        if (mod->has_init)
1820                buf_printf(b, " .init = init_module,\n");
1821        if (mod->has_cleanup)
1822                buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1823                              " .exit = cleanup_module,\n"
1824                              "#endif\n");
1825        buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1826        buf_printf(b, "};\n");
1827}
1828
1829static void add_staging_flag(struct buffer *b, const char *name)
1830{
1831        static const char *staging_dir = "drivers/staging";
1832
1833        if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1834                buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1835}
1836
1837/**
1838 * Record CRCs for unresolved symbols
1839 **/
1840static int add_versions(struct buffer *b, struct module *mod)
1841{
1842        struct symbol *s, *exp;
1843        int err = 0;
1844
1845        for (s = mod->unres; s; s = s->next) {
1846                exp = find_symbol(s->name);
1847                if (!exp || exp->module == mod) {
1848                        if (have_vmlinux && !s->weak) {
1849                                if (warn_unresolved) {
1850                                        warn("\"%s\" [%s.ko] undefined!\n",
1851                                             s->name, mod->name);
1852                                } else {
1853                                        merror("\"%s\" [%s.ko] undefined!\n",
1854                                                  s->name, mod->name);
1855                                        err = 1;
1856                                }
1857                        }
1858                        continue;
1859                }
1860                s->module = exp->module;
1861                s->crc_valid = exp->crc_valid;
1862                s->crc = exp->crc;
1863        }
1864
1865        if (!modversions)
1866                return err;
1867
1868        buf_printf(b, "\n");
1869        buf_printf(b, "static const struct modversion_info ____versions[]\n");
1870        buf_printf(b, "__used\n");
1871        buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1872
1873        for (s = mod->unres; s; s = s->next) {
1874                if (!s->module)
1875                        continue;
1876                if (!s->crc_valid) {
1877                        warn("\"%s\" [%s.ko] has no CRC!\n",
1878                                s->name, mod->name);
1879                        continue;
1880                }
1881                buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1882        }
1883
1884        buf_printf(b, "};\n");
1885
1886        return err;
1887}
1888
1889static void add_depends(struct buffer *b, struct module *mod,
1890                        struct module *modules)
1891{
1892        struct symbol *s;
1893        struct module *m;
1894        int first = 1;
1895
1896        for (m = modules; m; m = m->next)
1897                m->seen = is_vmlinux(m->name);
1898
1899        buf_printf(b, "\n");
1900        buf_printf(b, "static const char __module_depends[]\n");
1901        buf_printf(b, "__used\n");
1902        buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1903        buf_printf(b, "\"depends=");
1904        for (s = mod->unres; s; s = s->next) {
1905                const char *p;
1906                if (!s->module)
1907                        continue;
1908
1909                if (s->module->seen)
1910                        continue;
1911
1912                s->module->seen = 1;
1913                p = strrchr(s->module->name, '/');
1914                if (p)
1915                        p++;
1916                else
1917                        p = s->module->name;
1918                buf_printf(b, "%s%s", first ? "" : ",", p);
1919                first = 0;
1920        }
1921        buf_printf(b, "\";\n");
1922}
1923
1924static void add_srcversion(struct buffer *b, struct module *mod)
1925{
1926        if (mod->srcversion[0]) {
1927                buf_printf(b, "\n");
1928                buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1929                           mod->srcversion);
1930        }
1931}
1932
1933static void write_if_changed(struct buffer *b, const char *fname)
1934{
1935        char *tmp;
1936        FILE *file;
1937        struct stat st;
1938
1939        file = fopen(fname, "r");
1940        if (!file)
1941                goto write;
1942
1943        if (fstat(fileno(file), &st) < 0)
1944                goto close_write;
1945
1946        if (st.st_size != b->pos)
1947                goto close_write;
1948
1949        tmp = NOFAIL(malloc(b->pos));
1950        if (fread(tmp, 1, b->pos, file) != b->pos)
1951                goto free_write;
1952
1953        if (memcmp(tmp, b->p, b->pos) != 0)
1954                goto free_write;
1955
1956        free(tmp);
1957        fclose(file);
1958        return;
1959
1960 free_write:
1961        free(tmp);
1962 close_write:
1963        fclose(file);
1964 write:
1965        file = fopen(fname, "w");
1966        if (!file) {
1967                perror(fname);
1968                exit(1);
1969        }
1970        if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1971                perror(fname);
1972                exit(1);
1973        }
1974        fclose(file);
1975}
1976
1977/* parse Module.symvers file. line format:
1978 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1979 **/
1980static void read_dump(const char *fname, unsigned int kernel)
1981{
1982        unsigned long size, pos = 0;
1983        void *file = grab_file(fname, &size);
1984        char *line;
1985
1986        if (!file)
1987                /* No symbol versions, silently ignore */
1988                return;
1989
1990        while ((line = get_next_line(&pos, file, size))) {
1991                char *symname, *modname, *d, *export, *end;
1992                unsigned int crc;
1993                struct module *mod;
1994                struct symbol *s;
1995
1996                if (!(symname = strchr(line, '\t')))
1997                        goto fail;
1998                *symname++ = '\0';
1999                if (!(modname = strchr(symname, '\t')))
2000                        goto fail;
2001                *modname++ = '\0';
2002                if ((export = strchr(modname, '\t')) != NULL)
2003                        *export++ = '\0';
2004                if (export && ((end = strchr(export, '\t')) != NULL))
2005                        *end = '\0';
2006                crc = strtoul(line, &d, 16);
2007                if (*symname == '\0' || *modname == '\0' || *d != '\0')
2008                        goto fail;
2009                mod = find_module(modname);
2010                if (!mod) {
2011                        if (is_vmlinux(modname))
2012                                have_vmlinux = 1;
2013                        mod = new_module(modname);
2014                        mod->skip = 1;
2015                }
2016                s = sym_add_exported(symname, mod, export_no(export));
2017                s->kernel    = kernel;
2018                s->preloaded = 1;
2019                sym_update_crc(symname, mod, crc, export_no(export));
2020        }
2021        return;
2022fail:
2023        fatal("parse error in symbol dump file\n");
2024}
2025
2026/* For normal builds always dump all symbols.
2027 * For external modules only dump symbols
2028 * that are not read from kernel Module.symvers.
2029 **/
2030static int dump_sym(struct symbol *sym)
2031{
2032        if (!external_module)
2033                return 1;
2034        if (sym->vmlinux || sym->kernel)
2035                return 0;
2036        return 1;
2037}
2038
2039static void write_dump(const char *fname)
2040{
2041        struct buffer buf = { };
2042        struct symbol *symbol;
2043        int n;
2044
2045        for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2046                symbol = symbolhash[n];
2047                while (symbol) {
2048                        if (dump_sym(symbol))
2049                                buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2050                                        symbol->crc, symbol->name,
2051                                        symbol->module->name,
2052                                        export_str(symbol->export));
2053                        symbol = symbol->next;
2054                }
2055        }
2056        write_if_changed(&buf, fname);
2057}
2058
2059struct ext_sym_list {
2060        struct ext_sym_list *next;
2061        const char *file;
2062};
2063
2064int main(int argc, char **argv)
2065{
2066        struct module *mod;
2067        struct buffer buf = { };
2068        char *kernel_read = NULL, *module_read = NULL;
2069        char *dump_write = NULL;
2070        int opt;
2071        int err;
2072        struct ext_sym_list *extsym_iter;
2073        struct ext_sym_list *extsym_start = NULL;
2074
2075        while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2076                switch (opt) {
2077                case 'i':
2078                        kernel_read = optarg;
2079                        break;
2080                case 'I':
2081                        module_read = optarg;
2082                        external_module = 1;
2083                        break;
2084                case 'c':
2085                        cross_build = 1;
2086                        break;
2087                case 'e':
2088                        external_module = 1;
2089                        extsym_iter =
2090                           NOFAIL(malloc(sizeof(*extsym_iter)));
2091                        extsym_iter->next = extsym_start;
2092                        extsym_iter->file = optarg;
2093                        extsym_start = extsym_iter;
2094                        break;
2095                case 'm':
2096                        modversions = 1;
2097                        break;
2098                case 'o':
2099                        dump_write = optarg;
2100                        break;
2101                case 'a':
2102                        all_versions = 1;
2103                        break;
2104                case 's':
2105                        vmlinux_section_warnings = 0;
2106                        break;
2107                case 'S':
2108                        sec_mismatch_verbose = 0;
2109                        break;
2110                case 'w':
2111                        warn_unresolved = 1;
2112                        break;
2113                default:
2114                        exit(1);
2115                }
2116        }
2117
2118        if (kernel_read)
2119                read_dump(kernel_read, 1);
2120        if (module_read)
2121                read_dump(module_read, 0);
2122        while (extsym_start) {
2123                read_dump(extsym_start->file, 0);
2124                extsym_iter = extsym_start->next;
2125                free(extsym_start);
2126                extsym_start = extsym_iter;
2127        }
2128
2129        while (optind < argc)
2130                read_symbols(argv[optind++]);
2131
2132        for (mod = modules; mod; mod = mod->next) {
2133                if (mod->skip)
2134                        continue;
2135                check_exports(mod);
2136        }
2137
2138        err = 0;
2139
2140        for (mod = modules; mod; mod = mod->next) {
2141                char fname[strlen(mod->name) + 10];
2142
2143                if (mod->skip)
2144                        continue;
2145
2146                buf.pos = 0;
2147
2148                add_header(&buf, mod);
2149                add_staging_flag(&buf, mod->name);
2150                err |= add_versions(&buf, mod);
2151                add_depends(&buf, mod, modules);
2152                add_moddevtable(&buf, mod);
2153                add_srcversion(&buf, mod);
2154
2155                sprintf(fname, "%s.mod.c", mod->name);
2156                write_if_changed(&buf, fname);
2157        }
2158
2159        if (dump_write)
2160                write_dump(dump_write);
2161        if (sec_mismatch_count && !sec_mismatch_verbose)
2162                warn("modpost: Found %d section mismatch(es).\n"
2163                     "To see full details build your kernel with:\n"
2164                     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2165                     sec_mismatch_count);
2166
2167        return err;
2168}
2169