diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-07-01 19:24:31 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-07-01 19:24:31 +0300 |
commit | ad2885979ea6657fa8d3da51a301ec0e998ad8e7 (patch) | |
tree | 5cd569c8fa06995febbc6cd748283f9172814e60 /scripts/mod/modpost.c | |
parent | e3c2b10d6f15640407bef3098accf10faa4ecf1b (diff) | |
parent | f5983dab0ead92dc2690d147f0604a0badcac6a8 (diff) | |
download | linux-ad2885979ea6657fa8d3da51a301ec0e998ad8e7.tar.xz |
Merge tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Remove the deprecated rule to build *.dtbo from *.dts
- Refactor section mismatch detection in modpost
- Fix bogus ARM section mismatch detections
- Fix error of 'make gtags' with O= option
- Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error
with the latest LLVM version
- Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed
- Ignore more compiler-generated symbols for kallsyms
- Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles
- Enable more kernel-doc warnings with W=2
- Refactor <linux/export.h> by generating KSYMTAB data by modpost
- Deprecate <asm/export.h> and <asm-generic/export.h>
- Remove the EXPORT_DATA_SYMBOL macro
- Move the check for static EXPORT_SYMBOL back to modpost, which makes
the build faster
- Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm
- Warn missing MODULE_DESCRIPTION when building modules with W=1
- Make 'make clean' robust against too long argument error
- Exclude more objects from GCOV to fix CFI failures with GCOV
- Allow 'make modules_install' to install modules.builtin and
modules.builtin.modinfo even when CONFIG_MODULES is disabled
- Include modules.builtin and modules.builtin.modinfo in the
linux-image Debian package even when CONFIG_MODULES is disabled
- Revive "Entering directory" logging for the latest Make version
* tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (72 commits)
modpost: define more R_ARM_* for old distributions
kbuild: revive "Entering directory" for Make >= 4.4.1
kbuild: set correct abs_srctree and abs_objtree for package builds
scripts/mksysmap: Ignore prefixed KCFI symbols
kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb
kbuild: builddeb: always make modules_install, to install modules.builtin*
modpost: continue even with unknown relocation type
modpost: factor out Elf_Sym pointer calculation to section_rel()
modpost: factor out inst location calculation to section_rel()
kbuild: Disable GCOV for *.mod.o
kbuild: Fix CFI failures with GCOV
kbuild: make clean rule robust against too long argument error
script: modpost: emit a warning when the description is missing
kbuild: make modules_install copy modules.builtin(.modinfo)
linux/export.h: rename 'sec' argument to 'license'
modpost: show offset from symbol for section mismatch warnings
modpost: merge two similar section mismatch warnings
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion
modpost: use null string instead of NULL pointer for default namespace
modpost: squash sym_update_namespace() into sym_add_exported()
...
Diffstat (limited to 'scripts/mod/modpost.c')
-rw-r--r-- | scripts/mod/modpost.c | 785 |
1 files changed, 372 insertions, 413 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index c12150f96b88..b29b29707f10 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -35,6 +35,9 @@ 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 */ @@ -42,6 +45,8 @@ 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.) @@ -215,7 +220,9 @@ struct symbol { 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[]; }; @@ -297,6 +304,13 @@ 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; @@ -352,26 +366,8 @@ static const char *sec_name(const struct elf_info *info, unsigned int secindex) #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) -static void sym_update_namespace(const char *symname, const char *namespace) -{ - struct symbol *s = find_symbol(symname); - - /* - * That symbol should have been created earlier and thus this is - * actually an assertion. - */ - if (!s) { - error("Could not update namespace(%s) for symbol %s\n", - namespace, symname); - return; - } - - free(s->namespace); - s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; -} - static struct symbol *sym_add_exported(const char *name, struct module *mod, - bool gpl_only) + bool gpl_only, const char *namespace) { struct symbol *s = find_symbol(name); @@ -384,6 +380,7 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, 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); @@ -531,6 +528,8 @@ static int parse_elf(struct elf_info *info, const char *filename) 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) { @@ -653,18 +652,6 @@ static void handle_symbol(struct module *mod, struct elf_info *info, ELF_ST_BIND(sym->st_info) == STB_WEAK); break; default: - /* All exported symbols */ - if (strstarts(symname, "__ksymtab_")) { - const char *name, *secname; - - name = symname + strlen("__ksymtab_"); - secname = sec_name(info, get_secindex(info, sym)); - - if (strstarts(secname, "___ksymtab_gpl+")) - sym_add_exported(name, mod, true); - else if (strstarts(secname, "___ksymtab+")) - sym_add_exported(name, mod, false); - } if (strcmp(symname, "init_module") == 0) mod->has_init = true; if (strcmp(symname, "cleanup_module") == 0) @@ -838,34 +825,14 @@ static void check_section(const char *modname, struct elf_info *elf, #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ TEXT_SECTIONS, OTHER_TEXT_SECTIONS -/* init data sections */ -static const char *const init_data_sections[] = - { ALL_INIT_DATA_SECTIONS, NULL }; - -/* all init sections */ -static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; - -/* all text sections */ -static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; - -/* data section */ -static const char *const data_sections[] = { DATA_SECTIONS, NULL }; - -static const char *const head_sections[] = { ".head.text*", NULL }; -static const char *const linker_symbols[] = - { "__init_begin", "_sinittext", "_einittext", NULL }; -static const char *const optim_symbols[] = { "*.constprop.*", NULL }; - enum mismatch { TEXT_TO_ANY_INIT, DATA_TO_ANY_INIT, - TEXT_TO_ANY_EXIT, - DATA_TO_ANY_EXIT, + TEXTDATA_TO_ANY_EXIT, XXXINIT_TO_SOME_INIT, XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, - EXPORT_TO_INIT_EXIT, EXTABLE_TO_NON_TEXT, }; @@ -881,27 +848,14 @@ enum mismatch { * targeting sections in this array (white-list). Can be empty. * * @mismatch: Type of mismatch. - * - * @handler: Specific handler to call when a match is found. If NULL, - * default_mismatch_handler() will be called. - * */ struct sectioncheck { const char *fromsec[20]; const char *bad_tosec[20]; const char *good_tosec[20]; enum mismatch mismatch; - void (*handler)(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec); - }; -static void extable_mismatch_handler(const char *modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela *r, Elf_Sym *sym, - const char *fromsec); - static const struct sectioncheck sectioncheck[] = { /* Do not reference init/exit code/data from * normal code and data @@ -913,23 +867,13 @@ static const struct sectioncheck sectioncheck[] = { }, { .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_INIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { INIT_SECTIONS, NULL }, + .bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL }, .mismatch = DATA_TO_ANY_INIT, }, { - .fromsec = { TEXT_SECTIONS, NULL }, - .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = TEXT_TO_ANY_EXIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, + .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL }, .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_EXIT, + .mismatch = TEXTDATA_TO_ANY_EXIT, }, /* Do not reference init code/data from meminit code/data */ { @@ -960,12 +904,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, }, -/* Do not export init/exit functions or data */ -{ - .fromsec = { "___ksymtab*", NULL }, - .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, - .mismatch = EXPORT_TO_INIT_EXIT, -}, { .fromsec = { "__ex_table", NULL }, /* If you're adding any new black-listed sections in here, consider @@ -974,7 +912,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { ".altinstr_replacement", NULL }, .good_tosec = {ALL_TEXT_SECTIONS , NULL}, .mismatch = EXTABLE_TO_NON_TEXT, - .handler = extable_mismatch_handler, } }; @@ -1048,28 +985,19 @@ static const struct sectioncheck *section_mismatch( * fromsec = text section * refsymname = *.constprop.* * - * Pattern 6: - * Hide section mismatch warnings for ELF local symbols. The goal - * is to eliminate false positive modpost warnings caused by - * compiler-generated ELF local symbol names such as ".LANCHOR1". - * Autogenerated symbol names bypass modpost's "Pattern 2" - * whitelisting, which relies on pattern-matching against symbol - * names to work. (One situation where gcc can autogenerate ELF - * local symbols is when "-fsection-anchors" is used.) **/ -static int secref_whitelist(const struct sectioncheck *mismatch, - const char *fromsec, const char *fromsym, +static int secref_whitelist(const char *fromsec, const char *fromsym, const char *tosec, const char *tosym) { /* Check for pattern 1 */ - if (match(tosec, init_data_sections) && - match(fromsec, data_sections) && + 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, data_sections) && + match(fromsec, PATTERNS(DATA_SECTIONS)) && strstarts(fromsym, "__param_ops_")) return 0; @@ -1092,22 +1020,18 @@ static int secref_whitelist(const struct sectioncheck *mismatch, return 0; /* Check for pattern 3 */ - if (match(fromsec, head_sections) && - match(tosec, init_sections)) + if (strstarts(fromsec, ".head.text") && + match(tosec, PATTERNS(ALL_INIT_SECTIONS))) return 0; /* Check for pattern 4 */ - if (match(tosym, linker_symbols)) + if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext"))) return 0; /* Check for pattern 5 */ - if (match(fromsec, text_sections) && - match(tosec, init_sections) && - match(fromsym, optim_symbols)) - return 0; - - /* Check for pattern 6 */ - if (strstarts(fromsym, ".L")) + if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) && + match(tosec, PATTERNS(ALL_INIT_SECTIONS)) && + match(fromsym, PATTERNS("*.constprop.*"))) return 0; return 1; @@ -1131,303 +1055,210 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) return !is_mapping_symbol(name); } -/** - * 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, Elf64_Sword addr, - Elf_Sym *relsym) +/* Look up the nearest symbol based on the section and the address */ +static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance) { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf64_Sword distance = 20; - Elf64_Sword d; - unsigned int relsym_secindex; - - if (relsym->st_name != 0) - return relsym; + Elf_Addr sym_addr, distance; + bool is_arm = (elf->hdr->e_machine == EM_ARM); - relsym_secindex = get_secindex(elf, relsym); for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - if (get_secindex(elf, sym) != relsym_secindex) - continue; - if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) + if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; - if (sym->st_value == addr) - return sym; - /* Find a symbol nearby - addr are maybe negative */ - d = sym->st_value - addr; - if (d < 0) - d = addr - sym->st_value; - if (d < distance) { - distance = d; - near = sym; - } - } - /* We need a close match */ - if (distance < 20) - return near; - else - return NULL; -} -/* - * 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 Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, - const char *sec) -{ - Elf_Sym *sym; - Elf_Sym *near = NULL; - Elf_Addr distance = ~0; + sym_addr = sym->st_value; - for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - const char *symsec; + /* + * For ARM Thumb instruction, the bit 0 of st_value is set + * if the symbol is STT_FUNC type. Mask it to get the address. + */ + if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC) + sym_addr &= ~1; - if (is_shndx_special(sym->st_shndx)) - continue; - symsec = sec_name(elf, get_secindex(elf, sym)); - if (strcmp(symsec, sec) != 0) - continue; - if (!is_valid_name(elf, sym)) + if (addr >= sym_addr) + distance = addr - sym_addr; + else if (allow_negative) + distance = sym_addr - addr; + else continue; - if (sym->st_value <= addr && addr - sym->st_value <= distance) { - distance = addr - sym->st_value; + + if (distance <= min_distance) { + min_distance = distance; near = sym; } + + if (min_distance == 0) + break; } return near; } -static int is_function(Elf_Sym *sym) +static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx) { - if (sym) - return ELF_ST_TYPE(sym->st_info) == STT_FUNC; - else - return -1; + return find_nearest_sym(elf, addr, secndx, false, ~0); } -static inline void get_pretty_name(int is_func, const char** name, const char** name_p) +static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) { - switch (is_func) { - case 0: *name = "variable"; *name_p = ""; break; - case 1: *name = "function"; *name_p = "()"; break; - default: *name = "(unknown reference)"; *name_p = ""; break; - } + /* 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. + */ + return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20); } -/* - * 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 report_sec_mismatch(const char *modname, - const struct sectioncheck *mismatch, - const char *fromsec, - const char *fromsym, - const char *tosec, const char *tosym) +static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { - sec_mismatch_count++; + if (secndx >= elf->num_sections) + return false; - switch (mismatch->mismatch) { - case TEXT_TO_ANY_INIT: - case DATA_TO_ANY_INIT: - case TEXT_TO_ANY_EXIT: - case DATA_TO_ANY_EXIT: - case XXXINIT_TO_SOME_INIT: - case XXXEXIT_TO_SOME_EXIT: - case ANY_INIT_TO_ANY_EXIT: - case ANY_EXIT_TO_ANY_INIT: - warn("%s: section mismatch in reference: %s (section: %s) -> %s (section: %s)\n", - modname, fromsym, fromsec, tosym, tosec); - break; - case EXPORT_TO_INIT_EXIT: - warn("%s: EXPORT_SYMBOL used for init/exit symbol: %s (section: %s)\n", - modname, tosym, tosec); - break; - case EXTABLE_TO_NON_TEXT: - fatal("There's a special handler for this mismatch type, we should never get here.\n"); - break; - } + 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_Rela *r, Elf_Sym *sym, const char *fromsec) + Elf_Sym *tsym, + unsigned int fsecndx, const char *fromsec, Elf_Addr faddr, + const char *tosec, Elf_Addr taddr) { - const char *tosec; - Elf_Sym *to; Elf_Sym *from; const char *tosym; const char *fromsym; - from = find_elf_symbol2(elf, r->r_offset, fromsec); + from = find_fromsym(elf, faddr, fsecndx); fromsym = sym_name(elf, from); - tosec = sec_name(elf, get_secindex(elf, sym)); - to = find_elf_symbol(elf, r->r_addend, sym); - tosym = sym_name(elf, to); + tsym = find_tosym(elf, taddr, tsym); + tosym = sym_name(elf, tsym); /* check whitelist - we may ignore it */ - if (secref_whitelist(mismatch, - fromsec, fromsym, tosec, tosym)) { - report_sec_mismatch(modname, mismatch, - fromsec, fromsym, tosec, tosym); + 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->st_value), 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 int is_executable_section(struct elf_info* elf, unsigned int section_index) +static void check_export_symbol(struct module *mod, struct elf_info *elf, + Elf_Addr faddr, const char *secname, + Elf_Sym *sym) { - if (section_index > elf->num_sections) - fatal("section_index is outside elf->num_sections!\n"); + static const char *prefix = "__export_symbol_"; + const char *label_name, *name, *data; + Elf_Sym *label; + struct symbol *s; + bool is_gpl; - return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); -} + label = find_fromsym(elf, faddr, elf->export_symbol_secndx); + label_name = sym_name(elf, label); -/* - * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() - * to know the sizeof(struct exception_table_entry) for the target architecture. - */ -static unsigned int extable_entry_size = 0; -static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) -{ - /* - * If we're currently checking the second relocation within __ex_table, - * that relocation offset tells us the offsetof(struct - * exception_table_entry, fixup) which is equal to sizeof(struct - * exception_table_entry) divided by two. We use that to our advantage - * since there's no portable way to get that size as every architecture - * seems to go with different sized types. Not pretty but better than - * hard-coding the size for every architecture.. - */ - if (!extable_entry_size) - extable_entry_size = r->r_offset * 2; -} + if (!strstarts(label_name, prefix)) { + error("%s: .export_symbol section contains strange symbol '%s'\n", + mod->name, label_name); + return; + } -static inline bool is_extable_fault_address(Elf_Rela *r) -{ - /* - * extable_entry_size is only discovered after we've handled the - * _second_ relocation in __ex_table, so only abort when we're not - * handling the first reloc and extable_entry_size is zero. - */ - if (r->r_offset && extable_entry_size == 0) - fatal("extable_entry size hasn't been discovered!\n"); - - return ((r->r_offset == 0) || - (r->r_offset % extable_entry_size == 0)); -} - -#define is_second_extable_reloc(Start, Cur, Sec) \ - (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) - -static void report_extable_warnings(const char* modname, struct elf_info* elf, - const struct sectioncheck* const mismatch, - Elf_Rela* r, Elf_Sym* sym, - const char* fromsec, const char* tosec) -{ - Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); - const char* fromsym_name = sym_name(elf, fromsym); - Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); - const char* tosym_name = sym_name(elf, tosym); - const char* from_pretty_name; - const char* from_pretty_name_p; - const char* to_pretty_name; - const char* to_pretty_name_p; - - get_pretty_name(is_function(fromsym), - &from_pretty_name, &from_pretty_name_p); - get_pretty_name(is_function(tosym), - &to_pretty_name, &to_pretty_name_p); - - warn("%s(%s+0x%lx): Section mismatch in reference from the %s %s%s to the %s %s:%s%s\n", - modname, fromsec, (long)r->r_offset, from_pretty_name, - fromsym_name, from_pretty_name_p, - to_pretty_name, tosec, tosym_name, to_pretty_name_p); - - if (!match(tosec, mismatch->bad_tosec) && - is_executable_section(elf, get_secindex(elf, sym))) - fprintf(stderr, - "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)r->r_offset, tosec, tosec, tosec); -} - -static void extable_mismatch_handler(const char* modname, struct elf_info *elf, - const struct sectioncheck* const mismatch, - Elf_Rela* r, Elf_Sym* sym, - const char *fromsec) -{ - const char* tosec = sec_name(elf, get_secindex(elf, sym)); + 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; + } - sec_mismatch_count++; + 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; + } - report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec); - - 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)r->r_offset, tosec, modname); - else if (!is_executable_section(elf, get_secindex(elf, sym))) { - if (is_extable_fault_address(r)) - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not executable, IOW\n" - "it is not possible for the kernel to fault\n" - "at that address. Something is seriously wrong\n" - "and should be fixed.\n", - fromsec, (long)r->r_offset, tosec); - else - fatal("The relocation at %s+0x%lx references\n" - "section \"%s\" which is not executable, IOW\n" - "the kernel will fault if it ever tries to\n" - "jump to it. Something is seriously wrong\n" - "and should be fixed.\n", - fromsec, (long)r->r_offset, tosec); + 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); + + if (match(secname, PATTERNS(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(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(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) +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 = section_mismatch(fromsec, tosec); + const struct sectioncheck *mismatch; - if (mismatch) { - if (mismatch->handler) - mismatch->handler(modname, elf, mismatch, - r, sym, fromsec); - else - default_mismatch_handler(modname, elf, mismatch, - r, sym, fromsec); + if (elf->export_symbol_secndx == fsecndx) { + check_export_symbol(mod, elf, faddr, tosec, sym); + return; } -} -static unsigned int *reloc_location(struct elf_info *elf, - Elf_Shdr *sechdr, Elf_Rela *r) -{ - return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset); + mismatch = section_mismatch(fromsec, tosec); + if (!mismatch) + return; + + default_mismatch_handler(mod->name, elf, mismatch, sym, + fsecndx, fromsec, faddr, + tosec, taddr); } -static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_386_rel(uint32_t *location, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); switch (r_typ) { case R_386_32: @@ -1436,6 +1267,8 @@ static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) case R_386_PC32: r->r_addend = TO_NATIVE(*location) + 4; break; + default: + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1453,45 +1286,131 @@ static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #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 int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int32_t sign_extend32(int32_t value, int index) +{ + uint8_t shift = 31 - index; + + return (int32_t)(value << shift) >> shift; +} + +static int addend_arm_rel(void *loc, Elf_Sym *sym, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); + uint32_t inst, upper, lower, sign, j1, j2; + int32_t offset; 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)); + case R_ARM_REL32: + inst = TO_NATIVE(*(uint32_t *)loc); + r->r_addend = inst + sym->st_value; + break; + 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); + r->r_addend = offset + sym->st_value; break; 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); + r->r_addend = offset + sym->st_value + 8; + break; + 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); + r->r_addend = offset + sym->st_value; + break; + 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); + r->r_addend = offset + sym->st_value + 4; + break; case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: - case R_ARM_THM_JUMP19: - /* From ARM ABI: ((S + A) | T) - P */ - r->r_addend = (int)(long)(elf->hdr + - sechdr->sh_offset + - (r->r_offset - sechdr->sh_addr)); + /* + * 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); + r->r_addend = offset + sym->st_value + 4; break; default: - return 1; + r->r_addend = (Elf_Addr)(-1); } return 0; } -static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +static int addend_mips_rel(uint32_t *location, Elf_Rela *r) { unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); - unsigned int inst; + uint32_t inst; - if (r_typ == R_MIPS_HI16) - return 1; /* skip this */ inst = TO_NATIVE(*location); switch (r_typ) { case R_MIPS_LO16: @@ -1503,6 +1422,8 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) case R_MIPS_32: r->r_addend = inst; break; + default: + r->r_addend = (Elf_Addr)(-1); } return 0; } @@ -1523,19 +1444,17 @@ static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) #define R_LARCH_SUB32 55 #endif -static void section_rela(const char *modname, struct elf_info *elf, +static void section_rela(struct module *mod, struct elf_info *elf, Elf_Shdr *sechdr) { - Elf_Sym *sym; Elf_Rela *rela; Elf_Rela r; unsigned int r_sym; - const char *fromsec; - + unsigned int fsecndx = sechdr->sh_info; + const char *fromsec = sec_name(elf, fsecndx); Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; Elf_Rela *stop = (void *)start + sechdr->sh_size; - fromsec = sec_name(elf, sechdr->sh_info); /* if from section (name) is know good then skip it */ if (match(fromsec, section_white_list)) return; @@ -1570,34 +1489,31 @@ static void section_rela(const char *modname, struct elf_info *elf, continue; break; } - sym = elf->symtab_start + r_sym; - /* Skip special sections */ - if (is_shndx_special(sym->st_shndx)) - continue; - if (is_second_extable_reloc(start, rela, fromsec)) - find_extable_entry_size(fromsec, &r); - check_section_mismatch(modname, elf, &r, sym, fromsec); + + check_section_mismatch(mod, elf, elf->symtab_start + r_sym, + fsecndx, fromsec, r.r_offset, r.r_addend); } } -static void section_rel(const char *modname, struct elf_info *elf, +static void section_rel(struct module *mod, struct elf_info *elf, Elf_Shdr *sechdr) { - Elf_Sym *sym; Elf_Rel *rel; Elf_Rela r; unsigned int r_sym; - const char *fromsec; - + unsigned int fsecndx = sechdr->sh_info; + const char *fromsec = sec_name(elf, fsecndx); Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; Elf_Rel *stop = (void *)start + sechdr->sh_size; - fromsec = sec_name(elf, sechdr->sh_info); /* if from section (name) is know good then skip it */ if (match(fromsec, section_white_list)) return; for (rel = start; rel < stop; rel++) { + Elf_Sym *tsym; + void *loc; + r.r_offset = TO_NATIVE(rel->r_offset); #if KERNEL_ELFCLASS == ELFCLASS64 if (elf->hdr->e_machine == EM_MIPS) { @@ -1615,27 +1531,26 @@ static void section_rel(const char *modname, struct elf_info *elf, r_sym = ELF_R_SYM(r.r_info); #endif r.r_addend = 0; + + loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset); + tsym = elf->symtab_start + r_sym; + switch (elf->hdr->e_machine) { case EM_386: - if (addend_386_rel(elf, sechdr, &r)) - continue; + addend_386_rel(loc, &r); break; case EM_ARM: - if (addend_arm_rel(elf, sechdr, &r)) - continue; + addend_arm_rel(loc, tsym, &r); break; case EM_MIPS: - if (addend_mips_rel(elf, sechdr, &r)) - continue; + addend_mips_rel(loc, &r); break; + default: + fatal("Please add code to calculate addend for this architecture\n"); } - sym = elf->symtab_start + r_sym; - /* Skip special sections */ - if (is_shndx_special(sym->st_shndx)) - continue; - if (is_second_extable_reloc(start, rel, fromsec)) - find_extable_entry_size(fromsec, &r); - check_section_mismatch(modname, elf, &r, sym, fromsec); + + check_section_mismatch(mod, elf, tsym, + fsecndx, fromsec, r.r_offset, r.r_addend); } } @@ -1651,19 +1566,19 @@ static void section_rel(const char *modname, struct elf_info *elf, * to find all references to a section that reference a section that will * be discarded and warns about it. **/ -static void check_sec_ref(const char *modname, struct elf_info *elf) +static void check_sec_ref(struct module *mod, struct elf_info *elf) { int i; Elf_Shdr *sechdrs = elf->sechdrs; /* Walk through all sections */ for (i = 0; i < elf->num_sections; i++) { - check_section(modname, elf, &elf->sechdrs[i]); + check_section(mod->name, elf, &elf->sechdrs[i]); /* We want to process only relocation sections and not .init */ if (sechdrs[i].sh_type == SHT_RELA) - section_rela(modname, elf, &elf->sechdrs[i]); + section_rela(mod, elf, &elf->sechdrs[i]); else if (sechdrs[i].sh_type == SHT_REL) - section_rel(modname, elf, &elf->sechdrs[i]); + section_rel(mod, elf, &elf->sechdrs[i]); } } @@ -1818,6 +1733,8 @@ static void read_symbols(const char *modname) } } + 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); @@ -1825,16 +1742,7 @@ static void read_symbols(const char *modname) handle_moddevtable(mod, &info, sym, symname); } - for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { - symname = remove_dot(info.strtab + sym->st_name); - - /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */ - if (strstarts(symname, "__kstrtabns_")) - sym_update_namespace(symname + strlen("__kstrtabns_"), - sym_get_data(&info, sym)); - } - - check_sec_ref(modname, &info); + check_sec_ref(mod, &info); if (!mod->is_vmlinux) { version = get_modinfo(&info, "version"); @@ -1925,6 +1833,7 @@ static void check_exports(struct module *mod) continue; } + exp->used = true; s->module = exp->module; s->crc_valid = exp->crc_valid; s->crc = exp->crc; @@ -1935,8 +1844,7 @@ static void check_exports(struct module *mod) else basename = mod->name; - if (exp->namespace && - !contains_namespace(&mod->imported_namespaces, exp->namespace)) { + 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); @@ -1949,6 +1857,23 @@ static void check_exports(struct module *mod) } } +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; @@ -2022,12 +1947,26 @@ 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 <asm/asm-prototypes.h>?\n", @@ -2191,9 +2130,6 @@ static void write_mod_c_file(struct module *mod) char fname[PATH_MAX]; int ret; - check_modname_len(mod); - check_exports(mod); - add_header(&buf, mod); add_exported_symbols(&buf, mod); add_versions(&buf, mod); @@ -2265,9 +2201,8 @@ static void read_dump(const char *fname) mod = new_module(modname, strlen(modname)); mod->from_dump = true; } - s = sym_add_exported(symname, mod, gpl_only); + s = sym_add_exported(symname, mod, gpl_only, namespace); sym_set_crc(s, crc); - sym_update_namespace(symname, namespace); } free(buf); return; @@ -2286,10 +2221,13 @@ static void write_dump(const char *fname) 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 ?: ""); + sym->namespace); } } write_buf(&buf, fname); @@ -2328,12 +2266,13 @@ 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:mnT:o:awENd:")) != -1) { + while ((opt = getopt(argc, argv, "ei:mnT:to:au:WwENd:")) != -1) { switch (opt) { case 'e': external_module = true; @@ -2358,6 +2297,15 @@ int main(int argc, char **argv) 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; @@ -2388,6 +2336,17 @@ int main(int argc, char **argv) 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; |