/* Postprocess module symbol versions * * Copyright 2003 Kai Germaschewski * Copyright 2002-2004 Rusty Russell, IBM Corporation * Copyright 2006 Sam Ravnborg * Based in part on module-init-tools/depmod.c,file2alias * * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * * Usage: modpost vmlinux module1.o module2.o ... */ #include #include "modpost.h" #include "../../include/linux/license.h" /* Are we using CONFIG_MODVERSIONS? */ int modversions = 0; /* Warn about undefined symbols? (do so if we have vmlinux) */ int have_vmlinux = 0; /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ static int all_versions = 0; /* If we are modposting external module set to 1 */ static int external_module = 0; /* Warn about section mismatch in vmlinux if set to 1 */ static int vmlinux_section_warnings = 1; /* Only warn about unresolved symbols */ static int warn_unresolved = 0; /* How a symbol is exported */ enum export { export_plain, export_unused, export_gpl, export_unused_gpl, export_gpl_future, export_unknown }; void fatal(const char *fmt, ...) { va_list arglist; fprintf(stderr, "FATAL: "); va_start(arglist, fmt); vfprintf(stderr, fmt, arglist); va_end(arglist); exit(1); } void warn(const char *fmt, ...) { va_list arglist; fprintf(stderr, "WARNING: "); va_start(arglist, fmt); vfprintf(stderr, fmt, arglist); va_end(arglist); } void merror(const char *fmt, ...) { va_list arglist; fprintf(stderr, "ERROR: "); va_start(arglist, fmt); vfprintf(stderr, fmt, arglist); va_end(arglist); } static int is_vmlinux(const char *modname) { const char *myname; if ((myname = strrchr(modname, '/'))) myname++; else myname = modname; return (strcmp(myname, "vmlinux") == 0) || (strcmp(myname, "vmlinux.o") == 0); } void *do_nofail(void *ptr, const char *expr) { if (!ptr) { fatal("modpost: Memory allocation failure: %s.\n", expr); } return ptr; } /* A list of all modules we processed */ static struct module *modules; static struct module *find_module(char *modname) { struct module *mod; for (mod = modules; mod; mod = mod->next) if (strcmp(mod->name, modname) == 0) break; return mod; } static struct module *new_module(char *modname) { struct module *mod; char *p, *s; mod = NOFAIL(malloc(sizeof(*mod))); memset(mod, 0, sizeof(*mod)); p = NOFAIL(strdup(modname)); /* strip trailing .o */ if ((s = strrchr(p, '.')) != NULL) if (strcmp(s, ".o") == 0) *s = '\0'; /* add to list */ mod->name = p; mod->gpl_compatible = -1; mod->next = modules; modules = mod; return mod; } /* A hash of all exported symbols, * struct symbol is also used for lists of unresolved symbols */ #define SYMBOL_HASH_SIZE 1024 struct symbol { struct symbol *next; struct module *module; unsigned int crc; int crc_valid; unsigned int weak:1; unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ unsigned int kernel:1; /* 1 if symbol is from kernel * (only for external modules) **/ unsigned int preloaded:1; /* 1 if symbol from Module.symvers */ enum export export; /* Type of export */ char name[0]; }; static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; /* This is based on the hash agorithm from gdbm, via tdb */ static inline unsigned int tdb_hash(const char *name) { unsigned value; /* Used to compute the hash value. */ unsigned i; /* Used to cycle through random values. */ /* Set the initial value from the key size. */ for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++) value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); return (1103515243 * value + 12345); } /** * Allocate a new symbols for use in the hash of exported symbols or * the list of unresolved symbols per module **/ static struct symbol *alloc_symbol(const char *name, unsigned int weak, struct symbol *next) { struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); memset(s, 0, sizeof(*s)); strcpy(s->name, name); s->weak = weak; s->next = next; return s; } /* For the hash of exported symbols */ static struct symbol *new_symbol(const char *name, struct module *module, enum export export) { unsigned int hash; struct symbol *new; hash = tdb_hash(name) % SYMBOL_HASH_SIZE; new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); new->module = module; new->export = export; return new; } static struct symbol *find_symbol(const char *name) { struct symbol *s; /* For our purposes, .foo matches foo. PPC64 needs this. */ if (name[0] == '.') name++; for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) { if (strcmp(s->name, name) == 0) return s; } return NULL; } static struct { const char *str; enum export export; } export_list[] = { { .str = "EXPORT_SYMBOL", .export = export_plain }, { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused }, { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl }, { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl }, { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future }, { .str = "(unknown)", .export = export_unknown }, }; static const char *export_str(enum export ex) { return export_list[ex].str; } static enum export export_no(const char * s) { int i; if (!s) return export_unknown; for (i = 0; export_list[i].export != export_unknown; i++) { if (strcmp(export_list[i].str, s) == 0) return export_list[i].export; } return export_unknown; } static enum export export_from_sec(struct elf_info *elf, Elf_Section sec) { if (sec == elf->export_sec) return export_plain; else if (sec == elf->export_unused_sec) return export_unused; else if (sec == elf->export_gpl_sec) return export_gpl; else if (sec == elf->export_unused_gpl_sec) return export_unused_gpl; else if (sec == elf->export_gpl_future_sec) return export_gpl_future; else return export_unknown; } /** * Add an exported symbol - it may have already been added without a * CRC, in this case just update the CRC **/ static struct symbol *sym_add_exported(const char *name, struct module *mod, enum export export) { struct symbol *s = find_symbol(name); if (!s) { s = new_symbol(name, mod, export); } else { if (!s->preloaded) { warn("%s: '%s' exported twice. Previous export " "was in %s%s\n", mod->name, name, s->module->name, is_vmlinux(s->module->name) ?"":".ko"); } } s->preloaded = 0; s->vmlinux = is_vmlinux(mod->name); s->kernel = 0; s->export = export; return s; } static void sym_update_crc(const char *name, struct module *mod, unsigned int crc, enum export export) { struct symbol *s = find_symbol(name); if (!s) s = new_symbol(name, mod, export); s->crc = crc; s->crc_valid = 1; } void *grab_file(const char *filename, unsigned long *size) { struct stat st; void *map; int fd; fd = open(filename, O_RDONLY); if (fd < 0 || fstat(fd, &st) != 0) return NULL; *size = st.st_size; map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); close(fd); if (map == MAP_FAILED) return NULL; return map; } /** * Return a copy of the next line in a mmap'ed file. * spaces in the beginning of the line is trimmed away. * Return a pointer to a static buffer. **/ char* get_next_line(unsigned long *pos, void *file, unsigned long size) { static char line[4096]; int skip = 1; size_t len = 0; signed char *p = (signed char *)file + *pos; char *s = line; for (; *pos < size ; (*pos)++) { if (skip && isspace(*p)) { p++; continue; } skip = 0; if (*p != '\n' && (*pos < size)) { len++; *s++ = *p++; if (len > 4095) break; /* Too long, stop */ } else { /* End of string */ *s = '\0'; return line; } } /* End of buffer */ return NULL; } void release_file(void *file, unsigned long size) { munmap(file, size); } static int parse_elf(struct elf_info *info, const char *filename) { unsigned int i; Elf_Ehdr *hdr; Elf_Shdr *sechdrs; Elf_Sym *sym; hdr = grab_file(filename, &info->size); if (!hdr) { perror(filename); exit(1); } info->hdr = hdr; if (info->size < sizeof(*hdr)) { /* file too small, assume this is an empty .o file */ return 0; } /* Is this a valid ELF file? */ if ((hdr->e_ident[EI_MAG0] != ELFMAG0) || (hdr->e_ident[EI_MAG1] != ELFMAG1) || (hdr->e_ident[EI_MAG2] != ELFMAG2) || (hdr->e_ident[EI_MAG3] != ELFMAG3)) { /* Not an ELF file - silently ignore it */ return 0; } /* Fix endianness in ELF header */ hdr->e_shoff = TO_NATIVE(hdr->e_shoff); hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); hdr->e_shnum = TO_NATIVE(hdr->e_shnum); hdr->e_machine = TO_NATIVE(hdr->e_machine); hdr->e_type = TO_NATIVE(hdr->e_type); sechdrs = (void *)hdr + hdr->e_shoff; info->sechdrs = sechdrs; /* Fix endianness in section headers */ for (i = 0; i < hdr->e_shnum; i++) { sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info); sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); } /* Find symbol table. */ for (i = 1; i < hdr->e_shnum; i++) { const char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; const char *secname; if (sechdrs[i].sh_offset > info->size) { fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr)); return 0; } secname = secstrings + sechdrs[i].sh_name; if (strcmp(secname, ".modinfo") == 0) { info->modinfo = (void *)hdr + sechdrs[i].sh_offset; info->modinfo_len = sechdrs[i].sh_size; } else if (strcmp(secname, "__ksymtab") == 0) info->export_sec = i; else if (strcmp(secname, "__ksymtab_unused") == 0) info->export_unused_sec = i; else if (strcmp(secname, "__ksymtab_gpl") == 0) info->export_gpl_sec = i; else if (strcmp(secname, "__ksymtab_unused_gpl") == 0) info->export_unused_gpl_sec = i; else if (strcmp(secname, "__ksymtab_gpl_future") == 0) info->export_gpl_future_sec = i; if (sechdrs[i].sh_type != SHT_SYMTAB) continue; info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset + sechdrs[i].sh_size; info->strtab = (void *)hdr + sechdrs[sechdrs[i].sh_link].sh_offset; } if (!info->symtab_start) { fatal("%s has no symtab?\n", filename); } /* Fix endianness in symbols */ for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { sym->st_shndx = TO_NATIVE(sym->st_shndx); sym->st_name = TO_NATIVE(sym->st_name); sym->st_value = TO_NATIVE(sym->st_value); sym->st_size = TO_NATIVE(sym->st_size); } return 1; } static void parse_elf_finish(struct elf_info *info) { release_file(info->hdr, info->size); } #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_" #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_" static void handle_modversions(struct module *mod, struct elf_info *info, Elf_Sym *sym, const char *symname) { unsigned int crc; enum export export = export_from_sec(info, sym->st_shndx); switch (sym->st_shndx) { case SHN_COMMON: warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); break; case SHN_ABS: /* CRC'd symbol */ if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) { crc = (unsigned int) sym->st_value; sym_update_crc(symname + strlen(CRC_PFX), mod, crc, export); } break; case SHN_UNDEF: /* undefined symbol */ if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && ELF_ST_BIND(sym->st_info) != STB_WEAK) break; /* ignore global offset table */ if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) break; /* ignore __this_module, it will be resolved shortly */ if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0) break; /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) /* add compatibility with older glibc */ #ifndef STT_SPARC_REGISTER #define STT_SPARC_REGISTER STT_REGISTER #endif if (info->hdr->e_machine == EM_SPARC || info->hdr->e_machine == EM_SPARCV9) { /* Ignore register directives. */ if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) break; if (symname[0] == '.') { char *munged = strdup(symname); munged[0] = '_'; munged[1] = toupper(munged[1]); symname = munged; } } #endif if (memcmp(symname, MODULE_SYMBOL_PREFIX, strlen(MODULE_SYMBOL_PREFIX)) == 0) mod->unres = alloc_symbol(symname + strlen(MODULE_SYMBOL_PREFIX), ELF_ST_BIND(sym->st_info) == STB_WEAK, mod->unres); break; default: /* All exported symbols */ if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) { sym_add_exported(symname + strlen(KSYMTAB_PFX), mod, export); } if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0) mod->has_init = 1; if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0) mod->has_cleanup = 1; break; } } /** * Parse tag=value strings from .modinfo section **/ static char *next_string(char *string, unsigned long *secsize) { /* Skip non-zero chars */ while (string[0]) { string++; if ((*secsize)-- <= 1) return NULL; } /* Skip any zero padding. */ while (!string[0]) { string++; if ((*secsize)-- <= 1) return NULL; } return string; } static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len, const char *tag, char *info) { char *p; unsigned int taglen = strlen(tag); unsigned long size = modinfo_len; if (info) { size -= info - (char *)modinfo; modinfo = next_string(info, &size); } for (p = modinfo; p; p = next_string(p, &size)) { if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') return p + taglen + 1; } return NULL; } static char *get_modinfo(void *modinfo, unsigned long modinfo_len, const char *tag) { return get_next_modinfo(modinfo, modinfo_len, tag, NULL); } /** * Test if string s ends in string sub * return 0 if match **/ static int strrcmp(const char *s, const char *sub) { int slen, sublen; if (!s || !sub) return 1; slen = strlen(s); sublen = strlen(sub); if ((slen == 0) || (sublen == 0)) return 1; if (sublen > slen) return 1; return memcmp(s + slen - sublen, sub, sublen); } /* * Functions used only during module init is marked __init and is stored in * a .init.text section. Likewise data is marked __initdata and stored in * a .init.data section. * If this section is one of these sections return 1 * See include/linux/init.h for the details */ static int init_section(const char *name) { if (strcmp(name, ".init") == 0) return 1; if (strncmp(name, ".init.", strlen(".init.")) == 0) return 1; return 0; } /* * Functions used only during module exit is marked __exit and is stored in * a .exit.text section. Likewise data is marked __exitdata and stored in * a .exit.data section. * If this section is one of these sections return 1 * See include/linux/init.h for the details **/ static int exit_section(const char *name) { if (strcmp(name, ".exit.text") == 0) return 1; if (strcmp(name, ".exit.data") == 0) return 1; return 0; } /* * Data sections are named like this: * .data | .data.rel | .data.rel.* * Return 1 if the specified section is a data section */ static int data_section(const char *name) { if ((strcmp(name, ".data") == 0) || (strcmp(name, ".data.rel") == 0) || (strncmp(name, ".data.rel.", strlen(".data.rel.")) == 0)) return 1; else return 0; } /** * Whitelist to allow certain references to pass with no warning. * * Pattern 0: * Do not warn if funtion/data are marked with __init_refok/__initdata_refok. * The pattern is identified by: * fromsec = .text.init.refok* | .data.init.refok* * * Pattern 1: * If a module parameter is declared __initdata and permissions=0 * then this is legal despite the warning generated. * We cannot see value of permissions here, so just ignore * this pattern. * The pattern is identified by: * tosec = .init.data * fromsec = .data* * atsym =__param* * * Pattern 2: * Many drivers utilise a *driver container with references to * add, remove, probe functions etc. * These functions may often be marked __init and we do not want to * warn here. * the pattern is identified by: * tosec = init or exit section * fromsec = data section * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console, *_timer * * Pattern 3: * Whitelist all refereces from .text.head to .init.data * Whitelist all refereces from .text.head to .init.text * * Pattern 4: * Some symbols belong to init section but still it is ok to reference * these from non-init sections as these symbols don't have any memory * allocated for them and symbol address and value are same. So even * if init section is freed, its ok to reference those symbols. * For ex. symbols marking the init section boundaries. * This pattern is identified by * refsymname = __init_begin, _sinittext, _einittext * * Pattern 5: * Xtensa uses literal sections for constants that are accessed PC-relative. * Literal sections may safely reference their text sections. * (Note that the name for the literal section omits any trailing '.text') * tosec =
[.text] * fromsec =
.literal **/ static int secref_whitelist(const char *modname, const char *tosec, const char *fromsec, const char *atsym, const char *refsymname) { int len; const char **s; const char *pat2sym[] = { "driver", "_template", /* scsi uses *_template a lot */ "_timer", /* arm uses ops structures named _timer a lot */ "_sht", /* scsi also used *_sht to some extent */ "_ops", "_probe", "_probe_one", "_console", NULL }; const char *pat3refsym[] = { "__init_begin", "_sinittext", "_einittext", NULL }; /* Check for pattern 0 */ if ((strncmp(fromsec, ".text.init.refok", strlen(".text.init.refok")) == 0) || (strncmp(fromsec, ".data.init.refok", strlen(".data.init.refok")) == 0)) return 1; /* Check for pattern 1 */ if ((strcmp(tosec, ".init.data") == 0) && (strncmp(fromsec, ".data", strlen(".data")) == 0) && (strncmp(atsym, "__param", strlen("__param")) == 0)) return 1; /* Check for pattern 2 */ if ((init_section(tosec) || exit_section(tosec)) && data_section(fromsec)) for (s = pat2sym; *s; s++) if (strrcmp(atsym, *s) == 0) return 1; /* Check for pattern 3 */ if ((strcmp(fromsec, ".text.head") == 0) && ((strcmp(tosec, ".init.data") == 0) || (strcmp(tosec, ".init.text") == 0))) return 1; /* Check for pattern 4 */ for (s = pat3refsym; *s; s++) if (strcmp(refsymname, *s) == 0) return 1; /* Check for pattern 5 */ if (strrcmp(tosec, ".text") == 0) len = strlen(tosec) - strlen(".text"); else len = strlen(tosec); if ((strncmp(tosec, fromsec, len) == 0) && (strlen(fromsec) > len) && (strcmp(fromsec + len, ".literal") == 0)) return 1; return 0; } /** * Find symbol based on relocation record info. * In some cases the symbol supplied is a valid symbol so * return refsym. If st_name != 0 we assume this is a valid symbol. * In other cases the symbol needs to be looked up in the symbol table * based on section and address. * **/ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr, Elf_Sym *relsym) { Elf_Sym *sym; if (relsym->st_name != 0) return relsym; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (sym->st_shndx != relsym->st_shndx) continue; if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) continue; if (sym->st_value == addr) return sym; } return NULL; } static inline int is_arm_mapping_symbol(const char *str) { return str[0] == '$' && strchr("atd", str[1]) && (str[2] == '\0' || str[2] == '.'); } /* * If there's no name there, ignore it; likewise, ignore it if it's * one of the magic symbols emitted used by current ARM tools. * * Otherwise if find_symbols_between() returns those symbols, they'll * fail the whitelist tests and cause lots of false alarms ... fixable * only by merging __exit and __init sections into __text, bloating * the kernel (which is especially evil on embedded platforms). */ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) { const char *name = elf->strtab + sym->st_name; if (!name || !strlen(name)) return 0; return !is_arm_mapping_symbol(name); } /* * Find symbols before or equal addr and after addr - in the section sec. * If we find two symbols with equal offset prefer one with a valid name. * The ELF format may have a better way to detect what type of symbol * it is, but this works for now. **/ static void find_symbols_between(struct elf_info *elf, Elf_Addr addr, const char *sec, Elf_Sym **before, Elf_Sym **after) { Elf_Sym *sym; Elf_Ehdr *hdr = elf->hdr; Elf_Addr beforediff = ~0; Elf_Addr afterdiff = ~0; const char *secstrings = (void *)hdr + elf->sechdrs[hdr->e_shstrndx].sh_offset; *before = NULL; *after = NULL; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { const char *symsec; if (sym->st_shndx >= SHN_LORESERVE) continue; symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name; if (strcmp(symsec, sec) != 0) continue; if (!is_valid_name(elf, sym)) continue; if (sym->st_value <= addr) { if ((addr - sym->st_value) < beforediff) { beforediff = addr - sym->st_value; *before = sym; } else if ((addr - sym->st_value) == beforediff) { *before = sym; } } else { if ((sym->st_value - addr) < afterdiff) { afterdiff = sym->st_value - addr; *after = sym; } else if ((sym->st_value - addr) == afterdiff) { *after = sym; } } } } /** * Print a warning about a section mismatch. * Try to find symbols near it so user can find it. * Check whitelist before warning - it may be a false positive. **/ static void warn_sec_mismatch(const char *modname, const char *fromsec, struct elf_info *elf, Elf_Sym *sym, Elf_Rela r) { const char *refsymname = ""; Elf_Sym *before, *after; Elf_Sym *refsym; Elf_Ehdr *hdr = elf->hdr; Elf_Shdr *sechdrs = elf->sechdrs; const char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name; find_symbols_between(elf, r.r_offset, fromsec, &before, &after); refsym = find_elf_symbol(elf, r.r_addend, sym); if (refsym && strlen(elf->strtab + refsym->st_name)) refsymname = elf->strtab + refsym->st_name; /* check whitelist - we may ignore it */ if (secref_whitelist(modname, secname, fromsec, before ? elf->strtab + before->st_name : "", refsymname)) return; if (before && after) { warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s " "(between '%s' and '%s')\n", modname, fromsec, (unsigned long long)r.r_offset, secname, refsymname, elf->strtab + before->st_name, elf->strtab + after->st_name); } else if (before) { warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s " "(after '%s')\n", modname, fromsec, (unsigned long long)r.r_offset, secname, refsymname, elf->strtab + before->st_name); } else if (after) { warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s " "before '%s' (at offset -0x%llx)\n", modname, fromsec, (unsigned long long)r.r_offset, secname, refsymname, elf->strtab + after->st_name); } else { warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n", modname, fromsec, (unsigned long long)r.r_offset, secname, refsymname); } } static unsigned int *reloc_location(struct elf_info *elf, int rsection, Elf_Rela *r) { Elf_Shdr *sechdrs = elf->sechdrs; int section = sechdrs[rsection].sh_info; return (void *)elf->hdr + sechdrs[section].sh_offset + (r->r_offset - sechdrs[section].sh_addr); } static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); unsigned int *location = reloc_location(elf, rsection, r); switch (r_typ) { case R_386_32: r->r_addend = TO_NATIVE(*location); break; case R_386_PC32: r->r_addend = TO_NATIVE(*location) + 4; /* For CONFIG_RELOCATABLE=y */ if (elf->hdr->e_type == ET_EXEC) r->r_addend += r->r_offset; break; } return 0; } static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); switch (r_typ) { case R_ARM_ABS32: /* From ARM ABI: (S + A) | T */ r->r_addend = (int)(long)(elf->symtab_start + ELF_R_SYM(r->r_info)); break; case R_ARM_PC24: /* From ARM ABI: ((S + A) | T) - P */ r->r_addend = (int)(long)(elf->hdr + elf->sechdrs[rsection].sh_offset + (r->r_offset - elf->sechdrs[rsection].sh_addr)); break; default: return 1; } return 0; } static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); unsigned int *location = reloc_location(elf, rsection, r); unsigned int inst; if (r_typ == R_MIPS_HI16) return 1; /* skip this */ inst = TO_NATIVE(*location); switch (r_typ) { case R_MIPS_LO16: r->r_addend = inst & 0xffff; break; case R_MIPS_26: r->r_addend = (inst & 0x03ffffff) << 2; break; case R_MIPS_32: r->r_addend = inst; break; } return 0; } /** * A module includes a number of sections that are discarded * either when loaded or when used as built-in. * For loaded modules all functions marked __init and all data * marked __initdata will be discarded when the module has been intialized. * Likewise for modules used built-in the sections marked __exit * are discarded because __exit marked function are supposed to be called * only when a moduel is unloaded which never happes for built-in modules. * The check_sec_ref() function traverses all relocation records * to find all references to a section that reference a section that will * be discarded and warns about it. **/ static void check_sec_ref(struct module *mod, const char *modname, struct elf_info *elf, int section(const char*), int section_ref_ok(const char *)) { int i; Elf_Sym *sym; Elf_Ehdr *hdr = elf->hdr; Elf_Shdr *sechdrs = elf->sechdrs; const char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; /* Walk through all sections */ for (i = 0; i < hdr->e_shnum; i++) { const char *name = secstrings + sechdrs[i].sh_name; const char *secname; Elf_Rela r; unsigned int r_sym; /* We want to process only relocation sections and not .init */ if (sechdrs[i].sh_type == SHT_RELA) { Elf_Rela *rela; Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset; Elf_Rela *stop = (void*)start + sechdrs[i].sh_size; name += strlen(".rela"); if (section_ref_ok(name)) continue; for (rela = start; rela < stop; rela++) { r.r_offset = TO_NATIVE(rela->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (hdr->e_machine == EM_MIPS) { unsigned int r_typ; r_sym = ELF64_MIPS_R_SYM(rela->r_info); r_sym = TO_NATIVE(r_sym); r_typ = ELF64_MIPS_R_TYPE(rela->r_info); r.r_info = ELF64_R_INFO(r_sym, r_typ); } else { r.r_info = TO_NATIVE(rela->r_info); r_sym = ELF_R_SYM(r.r_info); } #else r.r_info = TO_NATIVE(rela->r_info); r_sym = ELF_R_SYM(r.r_info); #endif r.r_addend = TO_NATIVE(rela->r_addend); sym = elf->symtab_start + r_sym; /* Skip special sections */ if (sym->st_shndx >= SHN_LORESERVE) continue; secname = secstrings + sechdrs[sym->st_shndx].sh_name; if (section(secname)) warn_sec_mismatch(modname, name, elf, sym, r); } } else if (sechdrs[i].sh_type == SHT_REL) { Elf_Rel *rel; Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset; Elf_Rel *stop = (void*)start + sechdrs[i].sh_size; name += strlen(".rel"); if (section_ref_ok(name)) continue; for (rel = start; rel < stop; rel++) { r.r_offset = TO_NATIVE(rel->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (hdr->e_machine == EM_MIPS) { unsigned int r_typ; r_sym = ELF64_MIPS_R_SYM(rel->r_info); r_sym = TO_NATIVE(r_sym); r_typ = ELF64_MIPS_R_TYPE(rel->r_info); r.r_info = ELF64_R_INFO(r_sym, r_typ); } else { r.r_info = TO_NATIVE(rel->r_info); r_sym = ELF_R_SYM(r.r_info); } #else r.r_info = TO_NATIVE(rel->r_info); r_sym = ELF_R_SYM(r.r_info); #endif r.r_addend = 0; switch (hdr->e_machine) { case EM_386: if (addend_386_rel(elf, i, &r)) continue; break; case EM_ARM: if(addend_arm_rel(elf, i, &r)) continue; break; case EM_MIPS: if (addend_mips_rel(elf, i, &r)) continue; break; } sym = elf->symtab_start + r_sym; /* Skip special sections */ if (sym->st_shndx >= SHN_LORESERVE) continue; secname = secstrings + sechdrs[sym->st_shndx].sh_name; if (section(secname)) warn_sec_mismatch(modname, name, elf, sym, r); } } } } /* * Identify sections from which references to either a * .init or a .exit section is OK. * * [OPD] Keith Ownes commented: * For our future {in}sanity, add a comment that this is the ppc .opd * section, not the ia64 .opd section. * ia64 .opd should not point to discarded sections. * [.rodata] like for .init.text we ignore .rodata references -same reason */ static int initexit_section_ref_ok(const char *name) { const char **s; /* Absolute section names */ const char *namelist1[] = { "__bug_table", /* used by powerpc for BUG() */ "__ex_table", ".altinstructions", ".cranges", /* used by sh64 */ ".fixup", ".machvec", /* ia64 + powerpc uses these */ ".machine.desc", ".opd", /* See comment [OPD] */ "__dbe_table", ".parainstructions", ".pdr", ".plt", /* seen on ARCH=um build on x86_64. Harmless */ ".smp_locks", ".stab", ".m68k_fixup", ".xt.prop", /* xtensa informational section */ ".xt.lit", /* xtensa informational section */ NULL }; /* Start of section names */ const char *namelist2[] = { ".debug", ".eh_frame", ".note", /* ignore ELF notes - may contain anything */ ".got", /* powerpc - global offset table */ ".toc", /* powerpc - table of contents */ NULL }; /* part of section name */ const char *namelist3 [] = { ".unwind", /* Sample: IA_64.unwind.exit.text */ NULL }; for (s = namelist1; *s; s++) if (strcmp(*s, name) == 0) return 1; for (s = namelist2; *s; s++) if (strncmp(*s, name, strlen(*s)) == 0) return 1; for (s = namelist3; *s; s++) if (strstr(name, *s) != NULL) return 1; return 0; } /* * Identify sections from which references to a .init section is OK. * * Unfortunately references to read only data that referenced .init * sections had to be excluded. Almost all of these are false * positives, they are created by gcc. The downside of excluding rodata * is that there really are some user references from rodata to * init code, e.g. drivers/video/vgacon.c: * * const struct consw vga_con = { * con_startup: vgacon_startup, * * where vgacon_startup is __init. If you want to wade through the false * positives, take out the check for rodata. */ static int init_section_ref_ok(const char *name) { const char **s; /* Absolute section names */ const char *namelist1[] = { "__dbe_table", /* MIPS generate these */ "__ftr_fixup", /* powerpc cpu feature fixup */ "__fw_ftr_fixup", /* powerpc firmware feature fixup */ "__param", ".data.rel.ro", /* used by parisc64 */ ".init", ".text.lock", NULL }; /* Start of section names */ const char *namelist2[] = { ".init.", ".pci_fixup", ".rodata", NULL }; if (initexit_section_ref_ok(name)) return 1; for (s = namelist1; *s; s++) if (strcmp(*s, name) == 0) return 1; for (s = namelist2; *s; s++) if (strncmp(*s, name, strlen(*s)) == 0) return 1; /* If section name ends with ".init" we allow references * as is the case with .initcallN.init, .early_param.init, .taglist.init etc */ if (strrcmp(name, ".init") == 0) return 1; return 0; } /* * Identify sections from which references to a .exit section is OK. */ static int exit_section_ref_ok(const char *name) { const char **s; /* Absolute section names */ const char *namelist1[] = { ".exit.data", ".exit.text", ".exitcall.exit", ".rodata", NULL }; if (initexit_section_ref_ok(name)) return 1; for (s = namelist1; *s; s++) if (strcmp(*s, name) == 0) return 1; return 0; } static void read_symbols(char *modname) { const char *symname; char *version; char *license; struct module *mod; struct elf_info info = { }; Elf_Sym *sym; if (!parse_elf(&info, modname)) return; mod = new_module(modname); /* When there's no vmlinux, don't print warnings about * unresolved symbols (since there'll be too many ;) */ if (is_vmlinux(modname)) { have_vmlinux = 1; mod->skip = 1; } license = get_modinfo(info.modinfo, info.modinfo_len, "license"); while (license) { if (license_is_gpl_compatible(license)) mod->gpl_compatible = 1; else { mod->gpl_compatible = 0; break; } license = get_next_modinfo(info.modinfo, info.modinfo_len, "license", license); } for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { symname = info.strtab + sym->st_name; handle_modversions(mod, &info, sym, symname); handle_moddevtable(mod, &info, sym, symname); } if (is_vmlinux(modname) && vmlinux_section_warnings) { check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok); check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok); } version = get_modinfo(info.modinfo, info.modinfo_len, "version"); if (version) maybe_frob_rcs_version(modname, version, info.modinfo, version - (char *)info.hdr); if (version || (all_versions && !is_vmlinux(modname))) get_src_version(modname, mod->srcversion, sizeof(mod->srcversion)-1); parse_elf_finish(&info); /* Our trick to get versioning for struct_module - it's * never passed as an argument to an exported function, so * the automatic versioning doesn't pick it up, but it's really * important anyhow */ if (modversions) mod->unres = alloc_symbol("struct_module", 0, mod->unres); } #define SZ 500 /* We first write the generated file into memory using the * following helper, then compare to the file on disk and * only update the later if anything changed */ void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, const char *fmt, ...) { char tmp[SZ]; int len; va_list ap; va_start(ap, fmt); len = vsnprintf(tmp, SZ, fmt, ap); buf_write(buf, tmp, len); va_end(ap); } void buf_write(struct buffer *buf, const char *s, int len) { if (buf->size - buf->pos < len) { buf->size += len + SZ; buf->p = realloc(buf->p, buf->size); } strncpy(buf->p + buf->pos, s, len); buf->pos += len; } static void check_for_gpl_usage(enum export exp, const char *m, const char *s) { const char *e = is_vmlinux(m) ?"":".ko"; switch (exp) { case export_gpl: fatal("modpost: GPL-incompatible module %s%s " "uses GPL-only symbol '%s'\n", m, e, s); break; case export_unused_gpl: fatal("modpost: GPL-incompatible module %s%s " "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s); break; case export_gpl_future: warn("modpost: GPL-incompatible module %s%s " "uses future GPL-only symbol '%s'\n", m, e, s); break; case export_plain: case export_unused: case export_unknown: /* ignore */ break; } } static void check_for_unused(enum export exp, const char* m, const char* s) { const char *e = is_vmlinux(m) ?"":".ko"; switch (exp) { case export_unused: case export_unused_gpl: warn("modpost: module %s%s " "uses symbol '%s' marked UNUSED\n", m, e, s); break; default: /* ignore */ break; } } static void check_exports(struct module *mod) { struct symbol *s, *exp; for (s = mod->unres; s; s = s->next) { const char *basename; exp = find_symbol(s->name); if (!exp || exp->module == mod) continue; basename = strrchr(mod->name, '/'); if (basename) basename++; else basename = mod->name; if (!mod->gpl_compatible) check_for_gpl_usage(exp->export, basename, exp->name); check_for_unused(exp->export, basename, exp->name); } } /** * Header for the generated file **/ static void add_header(struct buffer *b, struct module *mod) { buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "\n"); buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); buf_printf(b, "\n"); buf_printf(b, "struct module __this_module\n"); buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); buf_printf(b, " .name = KBUILD_MODNAME,\n"); if (mod->has_init) buf_printf(b, " .init = init_module,\n"); if (mod->has_cleanup) buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" " .exit = cleanup_module,\n" "#endif\n"); buf_printf(b, " .arch = MODULE_ARCH_INIT,\n"); buf_printf(b, "};\n"); } /** * Record CRCs for unresolved symbols **/ static int add_versions(struct buffer *b, struct module *mod) { struct symbol *s, *exp; int err = 0; for (s = mod->unres; s; s = s->next) { exp = find_symbol(s->name); if (!exp || exp->module == mod) { if (have_vmlinux && !s->weak) { if (warn_unresolved) { warn("\"%s\" [%s.ko] undefined!\n", s->name, mod->name); } else { merror("\"%s\" [%s.ko] undefined!\n", s->name, mod->name); err = 1; } } continue; } s->module = exp->module; s->crc_valid = exp->crc_valid; s->crc = exp->crc; } if (!modversions) return err; buf_printf(b, "\n"); buf_printf(b, "static const struct modversion_info ____versions[]\n"); buf_printf(b, "__attribute_used__\n"); buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); for (s = mod->unres; s; s = s->next) { if (!s->module) { continue; } if (!s->crc_valid) { warn("\"%s\" [%s.ko] has no CRC!\n", s->name, mod->name); continue; } buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); } buf_printf(b, "};\n"); return err; } static void add_depends(struct buffer *b, struct module *mod, struct module *modules) { struct symbol *s; struct module *m; int first = 1; for (m = modules; m; m = m->next) { m->seen = is_vmlinux(m->name); } buf_printf(b, "\n"); buf_printf(b, "static const char __module_depends[]\n"); buf_printf(b, "__attribute_used__\n"); buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); buf_printf(b, "\"depends="); for (s = mod->unres; s; s = s->next) { const char *p; if (!s->module) continue; if (s->module->seen) continue; s->module->seen = 1; if ((p = strrchr(s->module->name, '/')) != NULL) p++; else p = s->module->name; buf_printf(b, "%s%s", first ? "" : ",", p); first = 0; } buf_printf(b, "\";\n"); } static void add_srcversion(struct buffer *b, struct module *mod) { if (mod->srcversion[0]) { buf_printf(b, "\n"); buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", mod->srcversion); } } static void write_if_changed(struct buffer *b, const char *fname) { char *tmp; FILE *file; struct stat st; file = fopen(fname, "r"); if (!file) goto write; if (fstat(fileno(file), &st) < 0) goto close_write; if (st.st_size != b->pos) goto close_write; tmp = NOFAIL(malloc(b->pos)); if (fread(tmp, 1, b->pos, file) != b->pos) goto free_write; if (memcmp(tmp, b->p, b->pos) != 0) goto free_write; free(tmp); fclose(file); return; free_write: free(tmp); close_write: fclose(file); write: file = fopen(fname, "w"); if (!file) { perror(fname); exit(1); } if (fwrite(b->p, 1, b->pos, file) != b->pos) { perror(fname); exit(1); } fclose(file); } /* parse Module.symvers file. line format: * 0x12345678symbolmodule[[export]something] **/ static void read_dump(const char *fname, unsigned int kernel) { unsigned long size, pos = 0; void *file = grab_file(fname, &size); char *line; if (!file) /* No symbol versions, silently ignore */ return; while ((line = get_next_line(&pos, file, size))) { char *symname, *modname, *d, *export, *end; unsigned int crc; struct module *mod; struct symbol *s; if (!(symname = strchr(line, '\t'))) goto fail; *symname++ = '\0'; if (!(modname = strchr(symname, '\t'))) goto fail; *modname++ = '\0'; if ((export = strchr(modname, '\t')) != NULL) *export++ = '\0'; if (export && ((end = strchr(export, '\t')) != NULL)) *end = '\0'; crc = strtoul(line, &d, 16); if (*symname == '\0' || *modname == '\0' || *d != '\0') goto fail; if (!(mod = find_module(modname))) { if (is_vmlinux(modname)) { have_vmlinux = 1; } mod = new_module(NOFAIL(strdup(modname))); mod->skip = 1; } s = sym_add_exported(symname, mod, export_no(export)); s->kernel = kernel; s->preloaded = 1; sym_update_crc(symname, mod, crc, export_no(export)); } return; fail: fatal("parse error in symbol dump file\n"); } /* For normal builds always dump all symbols. * For external modules only dump symbols * that are not read from kernel Module.symvers. **/ static int dump_sym(struct symbol *sym) { if (!external_module) return 1; if (sym->vmlinux || sym->kernel) return 0; return 1; } static void write_dump(const char *fname) { struct buffer buf = { }; struct symbol *symbol; int n; for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { symbol = symbolhash[n]; while (symbol) { if (dump_sym(symbol)) buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", symbol->crc, symbol->name, symbol->module->name, export_str(symbol->export)); symbol = symbol->next; } } write_if_changed(&buf, fname); } int main(int argc, char **argv) { struct module *mod; struct buffer buf = { }; char fname[SZ]; char *kernel_read = NULL, *module_read = NULL; char *dump_write = NULL; int opt; int err; while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) { switch(opt) { case 'i': kernel_read = optarg; break; case 'I': module_read = optarg; external_module = 1; break; case 'm': modversions = 1; break; case 'o': dump_write = optarg; break; case 'a': all_versions = 1; break; case 's': vmlinux_section_warnings = 0; break; case 'w': warn_unresolved = 1; break; default: exit(1); } } if (kernel_read) read_dump(kernel_read, 1); if (module_read) read_dump(module_read, 0); while (optind < argc) { read_symbols(argv[optind++]); } for (mod = modules; mod; mod = mod->next) { if (mod->skip) continue; check_exports(mod); } err = 0; for (mod = modules; mod; mod = mod->next) { if (mod->skip) continue; buf.pos = 0; add_header(&buf, mod); err |= add_versions(&buf, mod); add_depends(&buf, mod, modules); add_moddevtable(&buf, mod); add_srcversion(&buf, mod); sprintf(fname, "%s.mod.c", mod->name); write_if_changed(&buf, fname); } if (dump_write) write_dump(dump_write); return err; }