/* Postprocess module symbol versions * * Copyright 2003 Kai Germaschewski * Copyright 2002-2004 Rusty Russell, IBM Corporation * Copyright 2006-2008 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 ... */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include "modpost.h" #include "../../include/linux/license.h" static bool module_enabled; /* Are we using CONFIG_MODVERSIONS? */ static bool modversions; /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ static bool all_versions; /* If we are modposting external module set to 1 */ static bool external_module; /* Only warn about unresolved symbols */ static bool warn_unresolved; static int sec_mismatch_count; static bool sec_mismatch_warn_only = true; /* Trim EXPORT_SYMBOLs that are unused by in-tree modules */ static bool trim_unused_exports; /* ignore missing files */ static bool ignore_missing_files; /* If set to 1, only warn (instead of error) about missing ns imports */ static bool allow_missing_ns_imports; static bool error_occurred; static bool extra_warn; /* * Cut off the warnings when there are too many. This typically occurs when * vmlinux is missing. ('make modules' without building vmlinux.) */ #define MAX_UNRESOLVED_REPORTS 10 static unsigned int nr_unresolved; /* In kernel, this size is defined in linux/module.h; * here we use Elf_Addr instead of long for covering cross-compile */ #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr)) void modpost_log(enum loglevel loglevel, const char *fmt, ...) { va_list arglist; switch (loglevel) { case LOG_WARN: fprintf(stderr, "WARNING: "); break; case LOG_ERROR: fprintf(stderr, "ERROR: "); error_occurred = true; break; default: /* invalid loglevel, ignore */ break; } fprintf(stderr, "modpost: "); va_start(arglist, fmt); vfprintf(stderr, fmt, arglist); va_end(arglist); } static inline bool strends(const char *str, const char *postfix) { if (strlen(str) < strlen(postfix)) return false; return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; } void *do_nofail(void *ptr, const char *expr) { if (!ptr) fatal("Memory allocation failure: %s.\n", expr); return ptr; } char *read_text_file(const char *filename) { struct stat st; size_t nbytes; int fd; char *buf; fd = open(filename, O_RDONLY); if (fd < 0) { perror(filename); exit(1); } if (fstat(fd, &st) < 0) { perror(filename); exit(1); } buf = NOFAIL(malloc(st.st_size + 1)); nbytes = st.st_size; while (nbytes) { ssize_t bytes_read; bytes_read = read(fd, buf, nbytes); if (bytes_read < 0) { perror(filename); exit(1); } nbytes -= bytes_read; } buf[st.st_size] = '\0'; close(fd); return buf; } char *get_line(char **stringp) { char *orig = *stringp, *next; /* do not return the unwanted extra line at EOF */ if (!orig || *orig == '\0') return NULL; /* don't use strsep here, it is not available everywhere */ next = strchr(orig, '\n'); if (next) *next++ = '\0'; *stringp = next; return orig; } /* A list of all modules we processed */ LIST_HEAD(modules); static struct module *find_module(const char *modname) { struct module *mod; list_for_each_entry(mod, &modules, list) { if (strcmp(mod->name, modname) == 0) return mod; } return NULL; } static struct module *new_module(const char *name, size_t namelen) { struct module *mod; mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1)); memset(mod, 0, sizeof(*mod)); INIT_LIST_HEAD(&mod->exported_symbols); INIT_LIST_HEAD(&mod->unresolved_symbols); INIT_LIST_HEAD(&mod->missing_namespaces); INIT_LIST_HEAD(&mod->imported_namespaces); memcpy(mod->name, name, namelen); mod->name[namelen] = '\0'; mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0); /* * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE() * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue * modpost will exit wiht error anyway. */ mod->is_gpl_compatible = true; list_add_tail(&mod->list, &modules); 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 list_head list; /* link to module::exported_symbols or module::unresolved_symbols */ struct module *module; char *namespace; unsigned int crc; bool crc_valid; bool weak; bool is_func; bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ bool used; /* there exists a user of this symbol */ char name[]; }; static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; /* This is based on the hash algorithm 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) { struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); memset(s, 0, sizeof(*s)); strcpy(s->name, name); return s; } /* For the hash of exported symbols */ static void hash_add_symbol(struct symbol *sym) { unsigned int hash; hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE; sym->next = symbolhash[hash]; symbolhash[hash] = sym; } static void sym_add_unresolved(const char *name, struct module *mod, bool weak) { struct symbol *sym; sym = alloc_symbol(name); sym->weak = weak; list_add_tail(&sym->list, &mod->unresolved_symbols); } static struct symbol *sym_find_with_module(const char *name, struct module *mod) { 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 && (!mod || s->module == mod)) return s; } return NULL; } static struct symbol *find_symbol(const char *name) { return sym_find_with_module(name, NULL); } struct namespace_list { struct list_head list; char namespace[]; }; static bool contains_namespace(struct list_head *head, const char *namespace) { struct namespace_list *list; /* * The default namespace is null string "", which is always implicitly * contained. */ if (!namespace[0]) return true; list_for_each_entry(list, head, list) { if (!strcmp(list->namespace, namespace)) return true; } return false; } static void add_namespace(struct list_head *head, const char *namespace) { struct namespace_list *ns_entry; if (!contains_namespace(head, namespace)) { ns_entry = NOFAIL(malloc(sizeof(*ns_entry) + strlen(namespace) + 1)); strcpy(ns_entry->namespace, namespace); list_add_tail(&ns_entry->list, head); } } static void *sym_get_data_by_offset(const struct elf_info *info, unsigned int secindex, unsigned long offset) { Elf_Shdr *sechdr = &info->sechdrs[secindex]; return (void *)info->hdr + sechdr->sh_offset + offset; } void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym) { return sym_get_data_by_offset(info, get_secindex(info, sym), sym->st_value); } static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr) { return sym_get_data_by_offset(info, info->secindex_strings, sechdr->sh_name); } static const char *sec_name(const struct elf_info *info, unsigned int secindex) { /* * If sym->st_shndx is a special section index, there is no * corresponding section header. * Return "" if the index is out of range of info->sechdrs[] array. */ if (secindex >= info->num_sections) return ""; return sech_name(info, &info->sechdrs[secindex]); } #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) static struct symbol *sym_add_exported(const char *name, struct module *mod, bool gpl_only, const char *namespace) { struct symbol *s = find_symbol(name); if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) { error("%s: '%s' exported twice. Previous export was in %s%s\n", mod->name, name, s->module->name, s->module->is_vmlinux ? "" : ".ko"); } s = alloc_symbol(name); s->module = mod; s->is_gpl_only = gpl_only; s->namespace = NOFAIL(strdup(namespace)); list_add_tail(&s->list, &mod->exported_symbols); hash_add_symbol(s); return s; } static void sym_set_crc(struct symbol *sym, unsigned int crc) { sym->crc = crc; sym->crc_valid = true; } static void *grab_file(const char *filename, size_t *size) { struct stat st; void *map = MAP_FAILED; int fd; fd = open(filename, O_RDONLY); if (fd < 0) return NULL; if (fstat(fd, &st)) goto failed; *size = st.st_size; map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); failed: close(fd); if (map == MAP_FAILED) return NULL; return map; } static void release_file(void *file, size_t 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; const char *secstrings; unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U; hdr = grab_file(filename, &info->size); if (!hdr) { if (ignore_missing_files) { fprintf(stderr, "%s: %s (ignored)\n", filename, strerror(errno)); return 0; } 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_type = TO_NATIVE(hdr->e_type); hdr->e_machine = TO_NATIVE(hdr->e_machine); hdr->e_version = TO_NATIVE(hdr->e_version); hdr->e_entry = TO_NATIVE(hdr->e_entry); hdr->e_phoff = TO_NATIVE(hdr->e_phoff); hdr->e_shoff = TO_NATIVE(hdr->e_shoff); hdr->e_flags = TO_NATIVE(hdr->e_flags); hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize); hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize); hdr->e_phnum = TO_NATIVE(hdr->e_phnum); hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize); hdr->e_shnum = TO_NATIVE(hdr->e_shnum); hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); sechdrs = (void *)hdr + hdr->e_shoff; info->sechdrs = sechdrs; /* modpost only works for relocatable objects */ if (hdr->e_type != ET_REL) fatal("%s: not relocatable object.", filename); /* Check if file offset is correct */ if (hdr->e_shoff > info->size) fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n", (unsigned long)hdr->e_shoff, filename, info->size); if (hdr->e_shnum == SHN_UNDEF) { /* * There are more than 64k sections, * read count from .sh_size. */ info->num_sections = TO_NATIVE(sechdrs[0].sh_size); } else { info->num_sections = hdr->e_shnum; } if (hdr->e_shstrndx == SHN_XINDEX) { info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link); } else { info->secindex_strings = hdr->e_shstrndx; } /* Fix endianness in section headers */ for (i = 0; i < info->num_sections; i++) { sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags); sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); 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_info = TO_NATIVE(sechdrs[i].sh_info); sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign); sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize); } /* Find symbol table. */ secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset; for (i = 1; i < info->num_sections; i++) { const char *secname; int nobits = sechdrs[i].sh_type == SHT_NOBITS; if (!nobits && sechdrs[i].sh_offset > info->size) fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n", filename, (unsigned long)sechdrs[i].sh_offset, sizeof(*hdr)); secname = secstrings + sechdrs[i].sh_name; if (strcmp(secname, ".modinfo") == 0) { if (nobits) fatal("%s has NOBITS .modinfo\n", filename); info->modinfo = (void *)hdr + sechdrs[i].sh_offset; info->modinfo_len = sechdrs[i].sh_size; } else if (!strcmp(secname, ".export_symbol")) { info->export_symbol_secndx = i; } if (sechdrs[i].sh_type == SHT_SYMTAB) { unsigned int sh_link_idx; symtab_idx = i; info->symtab_start = (void *)hdr + sechdrs[i].sh_offset; info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset + sechdrs[i].sh_size; sh_link_idx = sechdrs[i].sh_link; info->strtab = (void *)hdr + sechdrs[sh_link_idx].sh_offset; } /* 32bit section no. table? ("more than 64k sections") */ if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) { symtab_shndx_idx = i; info->symtab_shndx_start = (void *)hdr + sechdrs[i].sh_offset; info->symtab_shndx_stop = (void *)hdr + sechdrs[i].sh_offset + sechdrs[i].sh_size; } } 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); } if (symtab_shndx_idx != ~0U) { Elf32_Word *p; if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link) fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n", filename, sechdrs[symtab_shndx_idx].sh_link, symtab_idx); /* Fix endianness */ for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop; p++) *p = TO_NATIVE(*p); } symsearch_init(info); return 1; } static void parse_elf_finish(struct elf_info *info) { symsearch_finish(info); release_file(info->hdr, info->size); } static int ignore_undef_symbol(struct elf_info *info, const char *symname) { /* ignore __this_module, it will be resolved shortly */ if (strcmp(symname, "__this_module") == 0) return 1; /* ignore global offset table */ if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) return 1; if (info->hdr->e_machine == EM_PPC) /* Special register function linked on all modules during final link of .ko */ if (strstarts(symname, "_restgpr_") || strstarts(symname, "_savegpr_") || strstarts(symname, "_rest32gpr_") || strstarts(symname, "_save32gpr_") || strstarts(symname, "_restvr_") || strstarts(symname, "_savevr_")) return 1; if (info->hdr->e_machine == EM_PPC64) /* Special register function linked on all modules during final link of .ko */ if (strstarts(symname, "_restgpr0_") || strstarts(symname, "_savegpr0_") || strstarts(symname, "_restvr_") || strstarts(symname, "_savevr_") || strcmp(symname, ".TOC.") == 0) return 1; if (info->hdr->e_machine == EM_S390) /* Expoline thunks are linked on all kernel modules during final link of .ko */ if (strstarts(symname, "__s390_indirect_jump_r")) return 1; /* Do not ignore this symbol */ return 0; } static void handle_symbol(struct module *mod, struct elf_info *info, const Elf_Sym *sym, const char *symname) { switch (sym->st_shndx) { case SHN_COMMON: if (strstarts(symname, "__gnu_lto_")) { /* Should warn here, but modpost runs before the linker */ } else warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); break; case SHN_UNDEF: /* undefined symbol */ if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && ELF_ST_BIND(sym->st_info) != STB_WEAK) break; if (ignore_undef_symbol(info, symname)) break; 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 = NOFAIL(strdup(symname)); munged[0] = '_'; munged[1] = toupper(munged[1]); symname = munged; } } sym_add_unresolved(symname, mod, ELF_ST_BIND(sym->st_info) == STB_WEAK); break; default: if (strcmp(symname, "init_module") == 0) mod->has_init = true; if (strcmp(symname, "cleanup_module") == 0) mod->has_cleanup = true; 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(struct elf_info *info, const char *tag, char *prev) { char *p; unsigned int taglen = strlen(tag); char *modinfo = info->modinfo; unsigned long size = info->modinfo_len; if (prev) { size -= prev - modinfo; modinfo = next_string(prev, &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(struct elf_info *info, const char *tag) { return get_next_modinfo(info, tag, NULL); } static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) { if (sym) return elf->strtab + sym->st_name; else return "(unknown)"; } /* * Check whether the 'string' argument matches one of the 'patterns', * an array of shell wildcard patterns (glob). * * Return true is there is a match. */ static bool match(const char *string, const char *const patterns[]) { const char *pattern; while ((pattern = *patterns++)) { if (!fnmatch(pattern, string, 0)) return true; } return false; } /* useful to pass patterns to match() directly */ #define PATTERNS(...) \ ({ \ static const char *const patterns[] = {__VA_ARGS__, NULL}; \ patterns; \ }) /* sections that we do not want to do full section mismatch check on */ static const char *const section_white_list[] = { ".comment*", ".debug*", ".zdebug*", /* Compressed debug sections. */ ".GCC.command.line", /* record-gcc-switches */ ".mdebug*", /* alpha, score, mips etc. */ ".pdr", /* alpha, score, mips etc. */ ".stab*", ".note*", ".got*", ".toc*", ".xt.prop", /* xtensa */ ".xt.lit", /* xtensa */ ".arcextmap*", /* arc */ ".gnu.linkonce.arcext*", /* arc : modules */ ".cmem*", /* EZchip */ ".fmt_slot*", /* EZchip */ ".gnu.lto*", ".discard.*", ".llvm.call-graph-profile", /* call graph */ NULL }; /* * This is used to find sections missing the SHF_ALLOC flag. * The cause of this is often a section specified in assembler * without "ax" / "aw". */ static void check_section(const char *modname, struct elf_info *elf, Elf_Shdr *sechdr) { const char *sec = sech_name(elf, sechdr); if (sechdr->sh_type == SHT_PROGBITS && !(sechdr->sh_flags & SHF_ALLOC) && !match(sec, section_white_list)) { warn("%s (%s): unexpected non-allocatable section.\n" "Did you forget to use \"ax\"/\"aw\" in a .S file?\n" "Note that for example contains\n" "section definitions for use in .S files.\n\n", modname, sec); } } #define ALL_INIT_DATA_SECTIONS \ ".init.setup", ".init.rodata", ".meminit.rodata", \ ".init.data", ".meminit.data" #define ALL_PCI_INIT_SECTIONS \ ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \ ".pci_fixup_enable", ".pci_fixup_resume", \ ".pci_fixup_resume_early", ".pci_fixup_suspend" #define ALL_XXXINIT_SECTIONS ".meminit.*" #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS #define ALL_EXIT_SECTIONS ".exit.*" #define DATA_SECTIONS ".data", ".data.rel" #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \ ".kprobes.text", ".cpuidle.text", ".noinstr.text", \ ".ltext", ".ltext.*" #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ ".fixup", ".entry.text", ".exception.text", \ ".coldtext", ".softirqentry.text" #define INIT_SECTIONS ".init.*" #define ALL_TEXT_SECTIONS ".init.text", ".meminit.text", ".exit.text", \ TEXT_SECTIONS, OTHER_TEXT_SECTIONS enum mismatch { TEXTDATA_TO_ANY_INIT_EXIT, XXXINIT_TO_SOME_INIT, ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, EXTABLE_TO_NON_TEXT, }; /** * Describe how to match sections on different criteria: * * @fromsec: Array of sections to be matched. * * @bad_tosec: Relocations applied to a section in @fromsec to a section in * this array is forbidden (black-list). Can be empty. * * @good_tosec: Relocations applied to a section in @fromsec must be * targeting sections in this array (white-list). Can be empty. * * @mismatch: Type of mismatch. */ struct sectioncheck { const char *fromsec[20]; const char *bad_tosec[20]; const char *good_tosec[20]; enum mismatch mismatch; }; static const struct sectioncheck sectioncheck[] = { /* Do not reference init/exit code/data from * normal code and data */ { .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL }, .bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }, .mismatch = TEXTDATA_TO_ANY_INIT_EXIT, }, /* Do not reference init code/data from meminit code/data */ { .fromsec = { ALL_XXXINIT_SECTIONS, NULL }, .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = XXXINIT_TO_SOME_INIT, }, /* Do not use exit code/data from init code */ { .fromsec = { ALL_INIT_SECTIONS, NULL }, .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, }, /* Do not use init code/data from exit code */ { .fromsec = { ALL_EXIT_SECTIONS, NULL }, .bad_tosec = { ALL_INIT_SECTIONS, NULL }, .mismatch = ANY_EXIT_TO_ANY_INIT, }, { .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, }, { .fromsec = { "__ex_table", NULL }, /* If you're adding any new black-listed sections in here, consider * adding a special 'printer' for them in scripts/check_extable. */ .bad_tosec = { ".altinstr_replacement", NULL }, .good_tosec = {ALL_TEXT_SECTIONS , NULL}, .mismatch = EXTABLE_TO_NON_TEXT, } }; static const struct sectioncheck *section_mismatch( const char *fromsec, const char *tosec) { int i; /* * The target section could be the SHT_NUL section when we're * handling relocations to un-resolved symbols, trying to match it * doesn't make much sense and causes build failures on parisc * architectures. */ if (*tosec == '\0') return NULL; for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) { const struct sectioncheck *check = §ioncheck[i]; if (match(fromsec, check->fromsec)) { if (check->bad_tosec[0] && match(tosec, check->bad_tosec)) return check; if (check->good_tosec[0] && !match(tosec, check->good_tosec)) return check; } } return NULL; } /** * Whitelist to allow certain references to pass with no warning. * * 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 1a: * module_param_call() ops can refer to __init set function if permissions=0 * The pattern is identified by: * tosec = .init.text * fromsec = .data* * atsym = __param_ops_* * * Pattern 3: * Whitelist all references from .head.text to any init section * * 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: * GCC may optimize static inlines when fed constant arg(s) resulting * in functions like cpumask_empty() -- generating an associated symbol * cpumask_empty.constprop.3 that appears in the audit. If the const that * is passed in comes from __init, like say nmi_ipi_mask, we get a * meaningless section warning. May need to add isra symbols too... * This pattern is identified by * tosec = init section * fromsec = text section * refsymname = *.constprop.* * **/ static int secref_whitelist(const char *fromsec, const char *fromsym, const char *tosec, const char *tosym) { /* Check for pattern 1 */ if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) && match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param")) return 0; /* Check for pattern 1a */ if (strcmp(tosec, ".init.text") == 0 && match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param_ops_")) return 0; /* symbols in data sections that may refer to any init/exit sections */ if (match(fromsec, PATTERNS(DATA_SECTIONS)) && match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) && match(fromsym, PATTERNS("*_ops", "*_probe", "*_console"))) return 0; /* * symbols in data sections must not refer to .exit.*, but there are * quite a few offenders, so hide these unless for W=1 builds until * these are fixed. */ if (!extra_warn && match(fromsec, PATTERNS(DATA_SECTIONS)) && match(tosec, PATTERNS(ALL_EXIT_SECTIONS)) && match(fromsym, PATTERNS("*driver"))) return 0; /* Check for pattern 3 */ if (strstarts(fromsec, ".head.text") && match(tosec, PATTERNS(ALL_INIT_SECTIONS))) return 0; /* Check for pattern 4 */ if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext"))) return 0; /* Check for pattern 5 */ if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) && match(tosec, PATTERNS(ALL_INIT_SECTIONS)) && match(fromsym, PATTERNS("*.constprop.*"))) return 0; return 1; } static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, unsigned int secndx) { return symsearch_find_nearest(elf, addr, secndx, false, ~0); } static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) { Elf_Sym *new_sym; /* If the supplied symbol has a valid name, return it */ if (is_valid_name(elf, sym)) return sym; /* * Strive to find a better symbol name, but the resulting name may not * match the symbol referenced in the original code. */ new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym), true, 20); return new_sym ? new_sym : sym; } static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { if (secndx >= elf->num_sections) return false; return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0; } static void default_mismatch_handler(const char *modname, struct elf_info *elf, const struct sectioncheck* const mismatch, Elf_Sym *tsym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, const char *tosec, Elf_Addr taddr) { Elf_Sym *from; const char *tosym; const char *fromsym; from = find_fromsym(elf, faddr, fsecndx); fromsym = sym_name(elf, from); tsym = find_tosym(elf, taddr, tsym); tosym = sym_name(elf, tsym); /* check whitelist - we may ignore it */ if (!secref_whitelist(fromsec, fromsym, tosec, tosym)) return; sec_mismatch_count++; warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n", modname, fromsym, (unsigned int)(faddr - (from ? from->st_value : 0)), fromsec, tosym, tosec); if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) { if (match(tosec, mismatch->bad_tosec)) fatal("The relocation at %s+0x%lx references\n" "section \"%s\" which is black-listed.\n" "Something is seriously wrong and should be fixed.\n" "You might get more information about where this is\n" "coming from by using scripts/check_extable.sh %s\n", fromsec, (long)faddr, tosec, modname); else if (is_executable_section(elf, get_secindex(elf, tsym))) warn("The relocation at %s+0x%lx references\n" "section \"%s\" which is not in the list of\n" "authorized sections. If you're adding a new section\n" "and/or if this reference is valid, add \"%s\" to the\n" "list of authorized sections to jump to on fault.\n" "This can be achieved by adding \"%s\" to\n" "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", fromsec, (long)faddr, tosec, tosec, tosec); else error("%s+0x%lx references non-executable section '%s'\n", fromsec, (long)faddr, tosec); } } static void check_export_symbol(struct module *mod, struct elf_info *elf, Elf_Addr faddr, const char *secname, Elf_Sym *sym) { static const char *prefix = "__export_symbol_"; const char *label_name, *name, *data; Elf_Sym *label; struct symbol *s; bool is_gpl; label = find_fromsym(elf, faddr, elf->export_symbol_secndx); label_name = sym_name(elf, label); if (!strstarts(label_name, prefix)) { error("%s: .export_symbol section contains strange symbol '%s'\n", mod->name, label_name); return; } if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && ELF_ST_BIND(sym->st_info) != STB_WEAK) { error("%s: local symbol '%s' was exported\n", mod->name, label_name + strlen(prefix)); return; } name = sym_name(elf, sym); if (strcmp(label_name + strlen(prefix), name)) { error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n", mod->name, name); return; } data = sym_get_data(elf, label); /* license */ if (!strcmp(data, "GPL")) { is_gpl = true; } else if (!strcmp(data, "")) { is_gpl = false; } else { error("%s: unknown license '%s' was specified for '%s'\n", mod->name, data, name); return; } data += strlen(data) + 1; /* namespace */ s = sym_add_exported(name, mod, is_gpl, data); /* * We need to be aware whether we are exporting a function or * a data on some architectures. */ s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC); /* * For parisc64, symbols prefixed $$ from the library have the symbol type * STT_LOPROC. They should be handled as functions too. */ if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 && elf->hdr->e_machine == EM_PARISC && ELF_ST_TYPE(sym->st_info) == STT_LOPROC) s->is_func = true; if (match(secname, PATTERNS(ALL_INIT_SECTIONS))) warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", mod->name, name); else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS))) warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", mod->name, name); } static void check_section_mismatch(struct module *mod, struct elf_info *elf, Elf_Sym *sym, unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, Elf_Addr taddr) { const char *tosec = sec_name(elf, get_secindex(elf, sym)); const struct sectioncheck *mismatch; if (module_enabled && elf->export_symbol_secndx == fsecndx) { check_export_symbol(mod, elf, faddr, tosec, sym); return; } mismatch = section_mismatch(fromsec, tosec); if (!mismatch) return; default_mismatch_handler(mod->name, elf, mismatch, sym, fsecndx, fromsec, faddr, tosec, taddr); } static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type) { switch (r_type) { case R_386_32: return TO_NATIVE(*location); case R_386_PC32: return TO_NATIVE(*location) + 4; } return (Elf_Addr)(-1); } #ifndef R_ARM_CALL #define R_ARM_CALL 28 #endif #ifndef R_ARM_JUMP24 #define R_ARM_JUMP24 29 #endif #ifndef R_ARM_THM_CALL #define R_ARM_THM_CALL 10 #endif #ifndef R_ARM_THM_JUMP24 #define R_ARM_THM_JUMP24 30 #endif #ifndef R_ARM_MOVW_ABS_NC #define R_ARM_MOVW_ABS_NC 43 #endif #ifndef R_ARM_MOVT_ABS #define R_ARM_MOVT_ABS 44 #endif #ifndef R_ARM_THM_MOVW_ABS_NC #define R_ARM_THM_MOVW_ABS_NC 47 #endif #ifndef R_ARM_THM_MOVT_ABS #define R_ARM_THM_MOVT_ABS 48 #endif #ifndef R_ARM_THM_JUMP19 #define R_ARM_THM_JUMP19 51 #endif static int32_t sign_extend32(int32_t value, int index) { uint8_t shift = 31 - index; return (int32_t)(value << shift) >> shift; } static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type) { uint32_t inst, upper, lower, sign, j1, j2; int32_t offset; switch (r_type) { case R_ARM_ABS32: case R_ARM_REL32: inst = TO_NATIVE(*(uint32_t *)loc); return inst + sym->st_value; case R_ARM_MOVW_ABS_NC: case R_ARM_MOVT_ABS: inst = TO_NATIVE(*(uint32_t *)loc); offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff), 15); return offset + sym->st_value; case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: inst = TO_NATIVE(*(uint32_t *)loc); offset = sign_extend32((inst & 0x00ffffff) << 2, 25); return offset + sym->st_value + 8; case R_ARM_THM_MOVW_ABS_NC: case R_ARM_THM_MOVT_ABS: upper = TO_NATIVE(*(uint16_t *)loc); lower = TO_NATIVE(*((uint16_t *)loc + 1)); offset = sign_extend32(((upper & 0x000f) << 12) | ((upper & 0x0400) << 1) | ((lower & 0x7000) >> 4) | (lower & 0x00ff), 15); return offset + sym->st_value; case R_ARM_THM_JUMP19: /* * Encoding T3: * S = upper[10] * imm6 = upper[5:0] * J1 = lower[13] * J2 = lower[11] * imm11 = lower[10:0] * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0') */ upper = TO_NATIVE(*(uint16_t *)loc); lower = TO_NATIVE(*((uint16_t *)loc + 1)); sign = (upper >> 10) & 1; j1 = (lower >> 13) & 1; j2 = (lower >> 11) & 1; offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) | ((upper & 0x03f) << 12) | ((lower & 0x07ff) << 1), 20); return offset + sym->st_value + 4; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: /* * Encoding T4: * S = upper[10] * imm10 = upper[9:0] * J1 = lower[13] * J2 = lower[11] * imm11 = lower[10:0] * I1 = NOT(J1 XOR S) * I2 = NOT(J2 XOR S) * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0') */ upper = TO_NATIVE(*(uint16_t *)loc); lower = TO_NATIVE(*((uint16_t *)loc + 1)); sign = (upper >> 10) & 1; j1 = (lower >> 13) & 1; j2 = (lower >> 11) & 1; offset = sign_extend32((sign << 24) | ((~(j1 ^ sign) & 1) << 23) | ((~(j2 ^ sign) & 1) << 22) | ((upper & 0x03ff) << 12) | ((lower & 0x07ff) << 1), 24); return offset + sym->st_value + 4; } return (Elf_Addr)(-1); } static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type) { uint32_t inst; inst = TO_NATIVE(*location); switch (r_type) { case R_MIPS_LO16: return inst & 0xffff; case R_MIPS_26: return (inst & 0x03ffffff) << 2; case R_MIPS_32: return inst; } return (Elf_Addr)(-1); } #ifndef EM_RISCV #define EM_RISCV 243 #endif #ifndef R_RISCV_SUB32 #define R_RISCV_SUB32 39 #endif #ifndef EM_LOONGARCH #define EM_LOONGARCH 258 #endif #ifndef R_LARCH_SUB32 #define R_LARCH_SUB32 55 #endif #ifndef R_LARCH_RELAX #define R_LARCH_RELAX 100 #endif #ifndef R_LARCH_ALIGN #define R_LARCH_ALIGN 102 #endif static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info, unsigned int *r_type, unsigned int *r_sym) { typedef struct { Elf64_Word r_sym; /* Symbol index */ unsigned char r_ssym; /* Special symbol for 2nd relocation */ unsigned char r_type3; /* 3rd relocation type */ unsigned char r_type2; /* 2nd relocation type */ unsigned char r_type; /* 1st relocation type */ } Elf64_Mips_R_Info; bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64); if (elf->hdr->e_machine == EM_MIPS && is_64bit) { Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info; *r_type = mips64_r_info->r_type; *r_sym = TO_NATIVE(mips64_r_info->r_sym); return; } if (is_64bit) r_info = TO_NATIVE((Elf64_Xword)r_info); else r_info = TO_NATIVE((Elf32_Word)r_info); *r_type = ELF_R_TYPE(r_info); *r_sym = ELF_R_SYM(r_info); } static void section_rela(struct module *mod, struct elf_info *elf, unsigned int fsecndx, const char *fromsec, const Elf_Rela *start, const Elf_Rela *stop) { const Elf_Rela *rela; for (rela = start; rela < stop; rela++) { Elf_Sym *tsym; Elf_Addr taddr, r_offset; unsigned int r_type, r_sym; r_offset = TO_NATIVE(rela->r_offset); get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym); tsym = elf->symtab_start + r_sym; taddr = tsym->st_value + TO_NATIVE(rela->r_addend); switch (elf->hdr->e_machine) { case EM_RISCV: if (!strcmp("__ex_table", fromsec) && r_type == R_RISCV_SUB32) continue; break; case EM_LOONGARCH: switch (r_type) { case R_LARCH_SUB32: if (!strcmp("__ex_table", fromsec)) continue; break; case R_LARCH_RELAX: case R_LARCH_ALIGN: /* These relocs do not refer to symbols */ continue; } break; } check_section_mismatch(mod, elf, tsym, fsecndx, fromsec, r_offset, taddr); } } static void section_rel(struct module *mod, struct elf_info *elf, unsigned int fsecndx, const char *fromsec, const Elf_Rel *start, const Elf_Rel *stop) { const Elf_Rel *rel; for (rel = start; rel < stop; rel++) { Elf_Sym *tsym; Elf_Addr taddr, r_offset; unsigned int r_type, r_sym; void *loc; r_offset = TO_NATIVE(rel->r_offset); get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym); loc = sym_get_data_by_offset(elf, fsecndx, r_offset); tsym = elf->symtab_start + r_sym; switch (elf->hdr->e_machine) { case EM_386: taddr = addend_386_rel(loc, r_type); break; case EM_ARM: taddr = addend_arm_rel(loc, tsym, r_type); break; case EM_MIPS: taddr = addend_mips_rel(loc, r_type); break; default: fatal("Please add code to calculate addend for this architecture\n"); } check_section_mismatch(mod, elf, tsym, fsecndx, fromsec, r_offset, taddr); } } /** * 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 initialized. * Likewise for modules used built-in the sections marked __exit * are discarded because __exit marked function are supposed to be called * only when a module is unloaded which never happens 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, struct elf_info *elf) { int i; /* Walk through all sections */ for (i = 0; i < elf->num_sections; i++) { Elf_Shdr *sechdr = &elf->sechdrs[i]; check_section(mod->name, elf, sechdr); /* We want to process only relocation sections and not .init */ if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) { /* section to which the relocation applies */ unsigned int secndx = sechdr->sh_info; const char *secname = sec_name(elf, secndx); const void *start, *stop; /* If the section is known good, skip it */ if (match(secname, section_white_list)) continue; start = sym_get_data_by_offset(elf, i, 0); stop = start + sechdr->sh_size; if (sechdr->sh_type == SHT_RELA) section_rela(mod, elf, secndx, secname, start, stop); else section_rel(mod, elf, secndx, secname, start, stop); } } } static char *remove_dot(char *s) { size_t n = strcspn(s, "."); if (n && s[n]) { size_t m = strspn(s + n + 1, "0123456789"); if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0)) s[n] = 0; } return s; } /* * The CRCs are recorded in .*.cmd files in the form of: * #SYMVER */ static void extract_crcs_for_object(const char *object, struct module *mod) { char cmd_file[PATH_MAX]; char *buf, *p; const char *base; int dirlen, ret; base = strrchr(object, '/'); if (base) { base++; dirlen = base - object; } else { dirlen = 0; base = object; } ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd", dirlen, object, base); if (ret >= sizeof(cmd_file)) { error("%s: too long path was truncated\n", cmd_file); return; } buf = read_text_file(cmd_file); p = buf; while ((p = strstr(p, "\n#SYMVER "))) { char *name; size_t namelen; unsigned int crc; struct symbol *sym; name = p + strlen("\n#SYMVER "); p = strchr(name, ' '); if (!p) break; namelen = p - name; p++; if (!isdigit(*p)) continue; /* skip this line */ crc = strtoul(p, &p, 0); if (*p != '\n') continue; /* skip this line */ name[namelen] = '\0'; /* * sym_find_with_module() may return NULL here. * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y. * Since commit e1327a127703, genksyms calculates CRCs of all * symbols, including trimmed ones. Ignore orphan CRCs. */ sym = sym_find_with_module(name, mod); if (sym) sym_set_crc(sym, crc); } free(buf); } /* * The symbol versions (CRC) are recorded in the .*.cmd files. * Parse them to retrieve CRCs for the current module. */ static void mod_set_crcs(struct module *mod) { char objlist[PATH_MAX]; char *buf, *p, *obj; int ret; if (mod->is_vmlinux) { strcpy(objlist, ".vmlinux.objs"); } else { /* objects for a module are listed in the *.mod file. */ ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name); if (ret >= sizeof(objlist)) { error("%s: too long path was truncated\n", objlist); return; } } buf = read_text_file(objlist); p = buf; while ((obj = strsep(&p, "\n")) && obj[0]) extract_crcs_for_object(obj, mod); free(buf); } static void read_symbols(const char *modname) { const char *symname; char *version; char *license; char *namespace; struct module *mod; struct elf_info info = { }; Elf_Sym *sym; if (!parse_elf(&info, modname)) return; if (!strends(modname, ".o")) { error("%s: filename must be suffixed with .o\n", modname); return; } /* strip trailing .o */ mod = new_module(modname, strlen(modname) - strlen(".o")); if (!mod->is_vmlinux) { license = get_modinfo(&info, "license"); if (!license) error("missing MODULE_LICENSE() in %s\n", modname); while (license) { if (!license_is_gpl_compatible(license)) { mod->is_gpl_compatible = false; break; } license = get_next_modinfo(&info, "license", license); } namespace = get_modinfo(&info, "import_ns"); while (namespace) { add_namespace(&mod->imported_namespaces, namespace); namespace = get_next_modinfo(&info, "import_ns", namespace); } } if (extra_warn && !get_modinfo(&info, "description")) warn("missing MODULE_DESCRIPTION() in %s\n", modname); for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { symname = remove_dot(info.strtab + sym->st_name); handle_symbol(mod, &info, sym, symname); handle_moddevtable(mod, &info, sym, symname); } check_sec_ref(mod, &info); if (!mod->is_vmlinux) { version = get_modinfo(&info, "version"); if (version || all_versions) get_src_version(mod->name, mod->srcversion, sizeof(mod->srcversion) - 1); } parse_elf_finish(&info); if (modversions) { /* * Our trick to get versioning for module struct etc. - 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. */ sym_add_unresolved("module_layout", mod, false); mod_set_crcs(mod); } } static void read_symbols_from_files(const char *filename) { FILE *in = stdin; char fname[PATH_MAX]; in = fopen(filename, "r"); if (!in) fatal("Can't open filenames file %s: %m", filename); while (fgets(fname, PATH_MAX, in) != NULL) { if (strends(fname, "\n")) fname[strlen(fname)-1] = '\0'; read_symbols(fname); } fclose(in); } #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 = NOFAIL(realloc(buf->p, buf->size)); } strncpy(buf->p + buf->pos, s, len); buf->pos += len; } static void check_exports(struct module *mod) { struct symbol *s, *exp; list_for_each_entry(s, &mod->unresolved_symbols, list) { const char *basename; exp = find_symbol(s->name); if (!exp) { if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS) modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR, "\"%s\" [%s.ko] undefined!\n", s->name, mod->name); continue; } if (exp->module == mod) { error("\"%s\" [%s.ko] was exported without definition\n", s->name, mod->name); continue; } exp->used = true; s->module = exp->module; s->crc_valid = exp->crc_valid; s->crc = exp->crc; basename = strrchr(mod->name, '/'); if (basename) basename++; else basename = mod->name; if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) { modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR, "module %s uses symbol %s from namespace %s, but does not import it.\n", basename, exp->name, exp->namespace); add_namespace(&mod->missing_namespaces, exp->namespace); } if (!mod->is_gpl_compatible && exp->is_gpl_only) error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n", basename, exp->name); } } static void handle_white_list_exports(const char *white_list) { char *buf, *p, *name; buf = read_text_file(white_list); p = buf; while ((name = strsep(&p, "\n"))) { struct symbol *sym = find_symbol(name); if (sym) sym->used = true; } free(buf); } static void check_modname_len(struct module *mod) { const char *mod_name; mod_name = strrchr(mod->name, '/'); if (mod_name == NULL) mod_name = mod->name; else mod_name++; if (strlen(mod_name) >= MODULE_NAME_LEN) error("module name is too long [%s.ko]\n", mod->name); } /** * Header for the generated file **/ static void add_header(struct buffer *b, struct module *mod) { buf_printf(b, "#include \n"); /* * Include build-salt.h after module.h in order to * inherit the definitions. */ buf_printf(b, "#define INCLUDE_VERMAGIC\n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "\n"); buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n"); buf_printf(b, "#include \n"); buf_printf(b, "ORC_HEADER;\n"); buf_printf(b, "#endif\n"); buf_printf(b, "\n"); buf_printf(b, "BUILD_SALT;\n"); buf_printf(b, "BUILD_LTO_INFO;\n"); buf_printf(b, "\n"); buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n"); buf_printf(b, "\n"); buf_printf(b, "__visible struct module __this_module\n"); buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n"); buf_printf(b, "\t.name = KBUILD_MODNAME,\n"); if (mod->has_init) buf_printf(b, "\t.init = init_module,\n"); if (mod->has_cleanup) buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" "\t.exit = cleanup_module,\n" "#endif\n"); buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); buf_printf(b, "};\n"); if (!external_module) buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); buf_printf(b, "\n" "#ifdef CONFIG_MITIGATION_RETPOLINE\n" "MODULE_INFO(retpoline, \"Y\");\n" "#endif\n"); if (strstarts(mod->name, "drivers/staging")) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); if (strstarts(mod->name, "tools/testing")) buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n"); } static void add_exported_symbols(struct buffer *buf, struct module *mod) { struct symbol *sym; /* generate struct for exported symbols */ buf_printf(buf, "\n"); list_for_each_entry(sym, &mod->exported_symbols, list) { if (trim_unused_exports && !sym->used) continue; buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", sym->is_func ? "FUNC" : "DATA", sym->name, sym->is_gpl_only ? "_gpl" : "", sym->namespace); } if (!modversions) return; /* record CRCs for exported symbols */ buf_printf(buf, "\n"); list_for_each_entry(sym, &mod->exported_symbols, list) { if (trim_unused_exports && !sym->used) continue; if (!sym->crc_valid) warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n" "Is \"%s\" prototyped in ?\n", sym->name, mod->name, mod->is_vmlinux ? "" : ".ko", sym->name); buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n", sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : ""); } } /** * Record CRCs for unresolved symbols **/ static void add_versions(struct buffer *b, struct module *mod) { struct symbol *s; if (!modversions) return; buf_printf(b, "\n"); buf_printf(b, "static const struct modversion_info ____versions[]\n"); buf_printf(b, "__used __section(\"__versions\") = {\n"); list_for_each_entry(s, &mod->unresolved_symbols, list) { if (!s->module) continue; if (!s->crc_valid) { warn("\"%s\" [%s.ko] has no CRC!\n", s->name, mod->name); continue; } if (strlen(s->name) >= MODULE_NAME_LEN) { error("too long symbol \"%s\" [%s.ko]\n", s->name, mod->name); break; } buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); } buf_printf(b, "};\n"); } static void add_depends(struct buffer *b, struct module *mod) { struct symbol *s; int first = 1; /* Clear ->seen flag of modules that own symbols needed by this. */ list_for_each_entry(s, &mod->unresolved_symbols, list) { if (s->module) s->module->seen = s->module->is_vmlinux; } buf_printf(b, "\n"); buf_printf(b, "MODULE_INFO(depends, \""); list_for_each_entry(s, &mod->unresolved_symbols, list) { const char *p; if (!s->module) continue; if (s->module->seen) continue; s->module->seen = true; p = strrchr(s->module->name, '/'); if (p) 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_buf(struct buffer *b, const char *fname) { FILE *file; if (error_occurred) return; file = fopen(fname, "w"); if (!file) { perror(fname); exit(1); } if (fwrite(b->p, 1, b->pos, file) != b->pos) { perror(fname); exit(1); } if (fclose(file) != 0) { perror(fname); exit(1); } } 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: write_buf(b, fname); } static void write_vmlinux_export_c_file(struct module *mod) { struct buffer buf = { }; buf_printf(&buf, "#include \n"); add_exported_symbols(&buf, mod); write_if_changed(&buf, ".vmlinux.export.c"); free(buf.p); } /* do sanity checks, and generate *.mod.c file */ static void write_mod_c_file(struct module *mod) { struct buffer buf = { }; char fname[PATH_MAX]; int ret; add_header(&buf, mod); add_exported_symbols(&buf, mod); add_versions(&buf, mod); add_depends(&buf, mod); add_moddevtable(&buf, mod); add_srcversion(&buf, mod); ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name); if (ret >= sizeof(fname)) { error("%s: too long path was truncated\n", fname); goto free; } write_if_changed(&buf, fname); free: free(buf.p); } /* parse Module.symvers file. line format: * 0x12345678symbolmoduleexportnamespace **/ static void read_dump(const char *fname) { char *buf, *pos, *line; buf = read_text_file(fname); if (!buf) /* No symbol versions, silently ignore */ return; pos = buf; while ((line = get_line(&pos))) { char *symname, *namespace, *modname, *d, *export; unsigned int crc; struct module *mod; struct symbol *s; bool gpl_only; if (!(symname = strchr(line, '\t'))) goto fail; *symname++ = '\0'; if (!(modname = strchr(symname, '\t'))) goto fail; *modname++ = '\0'; if (!(export = strchr(modname, '\t'))) goto fail; *export++ = '\0'; if (!(namespace = strchr(export, '\t'))) goto fail; *namespace++ = '\0'; crc = strtoul(line, &d, 16); if (*symname == '\0' || *modname == '\0' || *d != '\0') goto fail; if (!strcmp(export, "EXPORT_SYMBOL_GPL")) { gpl_only = true; } else if (!strcmp(export, "EXPORT_SYMBOL")) { gpl_only = false; } else { error("%s: unknown license %s. skip", symname, export); continue; } mod = find_module(modname); if (!mod) { mod = new_module(modname, strlen(modname)); mod->from_dump = true; } s = sym_add_exported(symname, mod, gpl_only, namespace); sym_set_crc(s, crc); } free(buf); return; fail: free(buf); fatal("parse error in symbol dump file\n"); } static void write_dump(const char *fname) { struct buffer buf = { }; struct module *mod; struct symbol *sym; list_for_each_entry(mod, &modules, list) { if (mod->from_dump) continue; list_for_each_entry(sym, &mod->exported_symbols, list) { if (trim_unused_exports && !sym->used) continue; buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", sym->crc, sym->name, mod->name, sym->is_gpl_only ? "_GPL" : "", sym->namespace); } } write_buf(&buf, fname); free(buf.p); } static void write_namespace_deps_files(const char *fname) { struct module *mod; struct namespace_list *ns; struct buffer ns_deps_buf = {}; list_for_each_entry(mod, &modules, list) { if (mod->from_dump || list_empty(&mod->missing_namespaces)) continue; buf_printf(&ns_deps_buf, "%s.ko:", mod->name); list_for_each_entry(ns, &mod->missing_namespaces, list) buf_printf(&ns_deps_buf, " %s", ns->namespace); buf_printf(&ns_deps_buf, "\n"); } write_if_changed(&ns_deps_buf, fname); free(ns_deps_buf.p); } struct dump_list { struct list_head list; const char *file; }; int main(int argc, char **argv) { struct module *mod; char *missing_namespace_deps = NULL; char *unused_exports_white_list = NULL; char *dump_write = NULL, *files_source = NULL; int opt; LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) { switch (opt) { case 'e': external_module = true; break; case 'i': dl = NOFAIL(malloc(sizeof(*dl))); dl->file = optarg; list_add_tail(&dl->list, &dump_lists); break; case 'M': module_enabled = true; break; case 'm': modversions = true; break; case 'n': ignore_missing_files = true; break; case 'o': dump_write = optarg; break; case 'a': all_versions = true; break; case 'T': files_source = optarg; break; case 't': trim_unused_exports = true; break; case 'u': unused_exports_white_list = optarg; break; case 'W': extra_warn = true; break; case 'w': warn_unresolved = true; break; case 'E': sec_mismatch_warn_only = false; break; case 'N': allow_missing_ns_imports = true; break; case 'd': missing_namespace_deps = optarg; break; default: exit(1); } } list_for_each_entry_safe(dl, dl2, &dump_lists, list) { read_dump(dl->file); list_del(&dl->list); free(dl); } while (optind < argc) read_symbols(argv[optind++]); if (files_source) read_symbols_from_files(files_source); list_for_each_entry(mod, &modules, list) { if (mod->from_dump || mod->is_vmlinux) continue; check_modname_len(mod); check_exports(mod); } if (unused_exports_white_list) handle_white_list_exports(unused_exports_white_list); list_for_each_entry(mod, &modules, list) { if (mod->from_dump) continue; if (mod->is_vmlinux) write_vmlinux_export_c_file(mod); else write_mod_c_file(mod); } if (missing_namespace_deps) write_namespace_deps_files(missing_namespace_deps); if (dump_write) write_dump(dump_write); if (sec_mismatch_count && !sec_mismatch_warn_only) error("Section mismatches detected.\n" "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); if (nr_unresolved > MAX_UNRESOLVED_REPORTS) warn("suppressed %u unresolved symbol warnings because there were too many)\n", nr_unresolved - MAX_UNRESOLVED_REPORTS); return error_occurred ? 1 : 0; }