From patchwork Wed May 11 16:45:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846481 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EED7C433F5 for ; Wed, 11 May 2022 16:50:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241439AbiEKQuC (ORCPT ); Wed, 11 May 2022 12:50:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345098AbiEKQt5 (ORCPT ); Wed, 11 May 2022 12:49:57 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82BC795DE7; Wed, 11 May 2022 09:49:48 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWbu031975; Thu, 12 May 2022 01:47:34 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWbu031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287654; bh=Ny/f8Cu0+NLDcW52IfYAsg1OMd0z3nWmReT0kJbf6as=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ydw5y1kY1EZVnz64D+61N55M54VgwG1CXDXGA8qPqLHArs4b/rte/pkUN6rsM4GzX 6Ukz4I9u2wvM+XtU7/MPAP+V/QJBLbwFuVog7mHxEWOR5BU1n4kJMGgvVK3/z+lsBk ZNSTpFjVUzeW9LWKsOsa/OB/PzcKKV+W9crxRerOffLPqiCbrTeXgO9HsuSYVHPV9B LHKzipTz8BYUZbW8C/64fZCkKvnUVQxAsocrbK/sK8S5Q4cLllH0wJgQ6289rX5Y/b cTZYa8oT2yje+bQFw/Oj1BhUjqZKKsDMtl6XVHy1mkvKVAmgtVOuQkIyPYc8Q+pe7T jRZUZbsXHS7cg== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 01/12] modpost: split the section mismatch checks into section-check.c Date: Thu, 12 May 2022 01:45:03 +0900 Message-Id: <20220511164514.2741934-2-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: modpost.c is too big, and the half of the code is for section checks. Split it. Also, move some related typedefs and macros from modpost.h to section-check.c Copy Sam's Copyright there. Commit b39927cf4cc5 ("kbuild: check for section mismatch during modpost stage") is the initial work for the section checks. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- Changes in v5: - Fix the build error (spotted by Nathan) - Do not do codying style changes (Suggested by Nick) - Copy Sam's copyright to the new file Changes in v4: - New patch scripts/mod/Makefile | 4 +- scripts/mod/modpost.c | 1202 +--------------------------------- scripts/mod/modpost.h | 34 +- scripts/mod/section-check.c | 1222 +++++++++++++++++++++++++++++++++++ 4 files changed, 1241 insertions(+), 1221 deletions(-) create mode 100644 scripts/mod/section-check.c diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile index c9e38ad937fd..6e548eb6317d 100644 --- a/scripts/mod/Makefile +++ b/scripts/mod/Makefile @@ -5,7 +5,7 @@ CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO) hostprogs-always-y += modpost mk_elfconfig always-y += empty.o -modpost-objs := modpost.o file2alias.o sumversion.o +modpost-objs := modpost.o section-check.o file2alias.o sumversion.o devicetable-offsets-file := devicetable-offsets.h @@ -16,7 +16,7 @@ targets += $(devicetable-offsets-file) devicetable-offsets.s # dependencies on generated files need to be listed explicitly -$(obj)/modpost.o $(obj)/file2alias.o $(obj)/sumversion.o: $(obj)/elfconfig.h +$(addprefix $(obj)/, $(modpost-objs)): $(obj)/elfconfig.h $(obj)/file2alias.o: $(obj)/$(devicetable-offsets-file) quiet_cmd_elfconfig = MKELF $@ diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index a78b75f0eeb0..e7e2c70a98f5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -31,7 +31,7 @@ static bool external_module; /* Only warn about unresolved symbols */ static bool warn_unresolved; -static int sec_mismatch_count; +int sec_mismatch_count; static bool sec_mismatch_warn_only = true; /* ignore missing files */ static bool ignore_missing_files; @@ -310,8 +310,8 @@ static void add_namespace(struct list_head *head, const char *namespace) } } -static void *sym_get_data_by_offset(const struct elf_info *info, - unsigned int secindex, unsigned long offset) +void *sym_get_data_by_offset(const struct elf_info *info, + unsigned int secindex, unsigned long offset) { Elf_Shdr *sechdr = &info->sechdrs[secindex]; @@ -327,19 +327,17 @@ static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym) sym->st_value); } -static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr) +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, int secindex) +const char *sec_name(const struct elf_info *info, int secindex) { return sech_name(info, &info->sechdrs[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); @@ -741,1196 +739,6 @@ static char *get_modinfo(struct elf_info *info, const char *tag) return get_next_modinfo(info, tag, NULL); } -/** - * Test if string s ends in string sub - * return 0 if match - **/ -static int strrcmp(const char *s, const char *sub) -{ - int slen, sublen; - - if (!s || !sub) - return 1; - - slen = strlen(s); - sublen = strlen(sub); - - if ((slen == 0) || (sublen == 0)) - return 1; - - if (sublen > slen) - return 1; - - return memcmp(s + slen - sublen, sub, sublen); -} - -static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) -{ - if (sym) - return elf->strtab + sym->st_name; - else - return "(unknown)"; -} - -/* The pattern is an array of simple patterns. - * "foo" will match an exact string equal to "foo" - * "*foo" will match a string that ends with "foo" - * "foo*" will match a string that begins with "foo" - * "*foo*" will match a string that contains "foo" - */ -static int match(const char *sym, const char * const pat[]) -{ - const char *p; - while (*pat) { - const char *endp; - - p = *pat++; - endp = p + strlen(p) - 1; - - /* "*foo*" */ - if (*p == '*' && *endp == '*') { - char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2)); - char *here = strstr(sym, bare); - - free(bare); - if (here != NULL) - return 1; - } - /* "*foo" */ - else if (*p == '*') { - if (strrcmp(sym, p + 1) == 0) - return 1; - } - /* "foo*" */ - else if (*endp == '*') { - if (strncmp(sym, p, strlen(p) - 1) == 0) - return 1; - } - /* no wildcards */ - else { - if (strcmp(p, sym) == 0) - return 1; - } - } - /* no match */ - return 0; -} - -/* sections that we do not want to do full section mismatch check on */ -static const char *const section_white_list[] = -{ - ".comment*", - ".debug*", - ".cranges", /* sh64 */ - ".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.*", - 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_EXIT_DATA_SECTIONS \ - ".exit.data", ".memexit.data" - -#define ALL_INIT_TEXT_SECTIONS \ - ".init.text", ".meminit.text" -#define ALL_EXIT_TEXT_SECTIONS \ - ".exit.text", ".memexit.text" - -#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 MEM_INIT_SECTIONS -#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS - -#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS -#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS - -#define DATA_SECTIONS ".data", ".data.rel" -#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ - ".kprobes.text", ".cpuidle.text", ".noinstr.text" -#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ - ".fixup", ".entry.text", ".exception.text", ".text.*", \ - ".coldtext", ".softirqentry.text" - -#define INIT_SECTIONS ".init.*" -#define MEM_INIT_SECTIONS ".meminit.*" - -#define EXIT_SECTIONS ".exit.*" -#define MEM_EXIT_SECTIONS ".memexit.*" - -#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 init and exit sections (code + data) */ -static const char *const init_exit_sections[] = - {ALL_INIT_SECTIONS, ALL_EXIT_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 }; - - -/* symbols in .data that may refer to init/exit sections */ -#define DEFAULT_SYMBOL_WHITE_LIST \ - "*driver", \ - "*_template", /* scsi uses *_template a lot */ \ - "*_timer", /* arm uses ops structures named _timer a lot */ \ - "*_sht", /* scsi also used *_sht to some extent */ \ - "*_ops", \ - "*_probe", \ - "*_probe_one", \ - "*_console" - -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, - 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, -}; - -/** - * 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. - * - * @symbol_white_list: Do not match a relocation to a symbol in this list - * even if it is targeting a section in @bad_to_sec. - * - * @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; - const char *symbol_white_list[20]; - 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 - */ -{ - .fromsec = { TEXT_SECTIONS, NULL }, - .bad_tosec = { ALL_INIT_SECTIONS, NULL }, - .mismatch = TEXT_TO_ANY_INIT, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_INIT, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { INIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_INIT, - .symbol_white_list = { - "*_template", "*_timer", "*_sht", "*_ops", - "*_probe", "*_probe_one", "*_console", NULL - }, -}, -{ - .fromsec = { TEXT_SECTIONS, NULL }, - .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = TEXT_TO_ANY_EXIT, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_EXIT, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -/* 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, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -/* Do not reference exit code/data from memexit code/data */ -{ - .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, - .bad_tosec = { EXIT_SECTIONS, NULL }, - .mismatch = XXXEXIT_TO_SOME_EXIT, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -/* 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, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -/* 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, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -{ - .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, - .bad_tosec = { INIT_SECTIONS, NULL }, - .mismatch = ANY_INIT_TO_ANY_EXIT, - .symbol_white_list = { NULL }, -}, -/* Do not export init/exit functions or data */ -{ - .fromsec = { "__ksymtab*", NULL }, - .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, - .mismatch = EXPORT_TO_INIT_EXIT, - .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, -}, -{ - .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, - .handler = extable_mismatch_handler, -} -}; - -static const struct sectioncheck *section_mismatch( - const char *fromsec, const char *tosec) -{ - int i; - int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck); - const struct sectioncheck *check = §ioncheck[0]; - - /* - * 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 < elems; 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; - } - 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 2: - * Many drivers utilise a *driver container with references to - * add, remove, probe functions etc. - * the pattern is identified by: - * tosec = init or exit section - * fromsec = data section - * atsym = *driver, *_template, *_sht, *_ops, *_probe, - * *probe_one, *_console, *_timer - * - * Pattern 3: - * Whitelist all 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.* - * - * 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, - const char *tosec, const char *tosym) -{ - /* Check for pattern 1 */ - if (match(tosec, init_data_sections) && - match(fromsec, data_sections) && - strstarts(fromsym, "__param")) - return 0; - - /* Check for pattern 1a */ - if (strcmp(tosec, ".init.text") == 0 && - match(fromsec, data_sections) && - strstarts(fromsym, "__param_ops_")) - return 0; - - /* Check for pattern 2 */ - if (match(tosec, init_exit_sections) && - match(fromsec, data_sections) && - match(fromsym, mismatch->symbol_white_list)) - return 0; - - /* Check for pattern 3 */ - if (match(fromsec, head_sections) && - match(tosec, init_sections)) - return 0; - - /* Check for pattern 4 */ - if (match(tosym, linker_symbols)) - 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")) - return 0; - - return 1; -} - -static inline int is_arm_mapping_symbol(const char *str) -{ - return str[0] == '$' && strchr("axtd", str[1]) - && (str[2] == '\0' || str[2] == '.'); -} - -/* - * If there's no name there, ignore it; likewise, ignore it if it's - * one of the magic symbols emitted used by current ARM tools. - * - * Otherwise if find_symbols_between() returns those symbols, they'll - * fail the whitelist tests and cause lots of false alarms ... fixable - * only by merging __exit and __init sections into __text, bloating - * the kernel (which is especially evil on embedded platforms). - */ -static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) -{ - const char *name = elf->strtab + sym->st_name; - - if (!name || !strlen(name)) - return 0; - return !is_arm_mapping_symbol(name); -} - -/** - * Find 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) -{ - 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; - - 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) - 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; - - for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - const char *symsec; - - 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)) - continue; - if (sym->st_value <= addr) { - if ((addr - sym->st_value) < distance) { - distance = addr - sym->st_value; - near = sym; - } else if ((addr - sym->st_value) == distance) { - near = sym; - } - } - } - return near; -} - -/* - * Convert a section name to the function/data attribute - * .init.text => __init - * .memexitconst => __memconst - * etc. - * - * The memory of returned value has been allocated on a heap. The user of this - * method should free it after usage. -*/ -static char *sec2annotation(const char *s) -{ - if (match(s, init_exit_sections)) { - char *p = NOFAIL(malloc(20)); - char *r = p; - - *p++ = '_'; - *p++ = '_'; - if (*s == '.') - s++; - while (*s && *s != '.') - *p++ = *s++; - *p = '\0'; - if (*s == '.') - s++; - if (strstr(s, "rodata") != NULL) - strcat(p, "const "); - else if (strstr(s, "data") != NULL) - strcat(p, "data "); - else - strcat(p, " "); - return r; - } else { - return NOFAIL(strdup("")); - } -} - -static int is_function(Elf_Sym *sym) -{ - if (sym) - return ELF_ST_TYPE(sym->st_info) == STT_FUNC; - else - return -1; -} - -static void print_section_list(const char * const list[20]) -{ - const char *const *s = list; - - while (*s) { - fprintf(stderr, "%s", *s); - s++; - if (*s) - fprintf(stderr, ", "); - } - fprintf(stderr, "\n"); -} - -static inline void get_pretty_name(int is_func, const char** name, const char** name_p) -{ - switch (is_func) { - case 0: *name = "variable"; *name_p = ""; break; - case 1: *name = "function"; *name_p = "()"; break; - default: *name = "(unknown reference)"; *name_p = ""; break; - } -} - -/* - * 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, - unsigned long long fromaddr, - const char *fromsym, - int from_is_func, - const char *tosec, const char *tosym, - int to_is_func) -{ - const char *from, *from_p; - const char *to, *to_p; - char *prl_from; - char *prl_to; - - sec_mismatch_count++; - - get_pretty_name(from_is_func, &from, &from_p); - get_pretty_name(to_is_func, &to, &to_p); - - warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " - "to the %s %s:%s%s\n", - modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, - tosym, to_p); - - switch (mismatch->mismatch) { - case TEXT_TO_ANY_INIT: - prl_from = sec2annotation(fromsec); - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The function %s%s() references\n" - "the %s %s%s%s.\n" - "This is often because %s lacks a %s\n" - "annotation or the annotation of %s is wrong.\n", - prl_from, fromsym, - to, prl_to, tosym, to_p, - fromsym, prl_to, tosym); - free(prl_from); - free(prl_to); - break; - case DATA_TO_ANY_INIT: { - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The variable %s references\n" - "the %s %s%s%s\n" - "If the reference is valid then annotate the\n" - "variable with __init* or __refdata (see linux/init.h) " - "or name the variable:\n", - fromsym, to, prl_to, tosym, to_p); - print_section_list(mismatch->symbol_white_list); - free(prl_to); - break; - } - case TEXT_TO_ANY_EXIT: - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The function %s() references a %s in an exit section.\n" - "Often the %s %s%s has valid usage outside the exit section\n" - "and the fix is to remove the %sannotation of %s.\n", - fromsym, to, to, tosym, to_p, prl_to, tosym); - free(prl_to); - break; - case DATA_TO_ANY_EXIT: { - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The variable %s references\n" - "the %s %s%s%s\n" - "If the reference is valid then annotate the\n" - "variable with __exit* (see linux/init.h) or " - "name the variable:\n", - fromsym, to, prl_to, tosym, to_p); - print_section_list(mismatch->symbol_white_list); - free(prl_to); - break; - } - case XXXINIT_TO_SOME_INIT: - case XXXEXIT_TO_SOME_EXIT: - prl_from = sec2annotation(fromsec); - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The %s %s%s%s references\n" - "a %s %s%s%s.\n" - "If %s is only used by %s then\n" - "annotate %s with a matching annotation.\n", - from, prl_from, fromsym, from_p, - to, prl_to, tosym, to_p, - tosym, fromsym, tosym); - free(prl_from); - free(prl_to); - break; - case ANY_INIT_TO_ANY_EXIT: - prl_from = sec2annotation(fromsec); - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The %s %s%s%s references\n" - "a %s %s%s%s.\n" - "This is often seen when error handling " - "in the init function\n" - "uses functionality in the exit path.\n" - "The fix is often to remove the %sannotation of\n" - "%s%s so it may be used outside an exit section.\n", - from, prl_from, fromsym, from_p, - to, prl_to, tosym, to_p, - prl_to, tosym, to_p); - free(prl_from); - free(prl_to); - break; - case ANY_EXIT_TO_ANY_INIT: - prl_from = sec2annotation(fromsec); - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The %s %s%s%s references\n" - "a %s %s%s%s.\n" - "This is often seen when error handling " - "in the exit function\n" - "uses functionality in the init path.\n" - "The fix is often to remove the %sannotation of\n" - "%s%s so it may be used outside an init section.\n", - from, prl_from, fromsym, from_p, - to, prl_to, tosym, to_p, - prl_to, tosym, to_p); - free(prl_from); - free(prl_to); - break; - case EXPORT_TO_INIT_EXIT: - prl_to = sec2annotation(tosec); - fprintf(stderr, - "The symbol %s is exported and annotated %s\n" - "Fix this by removing the %sannotation of %s " - "or drop the export.\n", - tosym, prl_to, prl_to, tosym); - free(prl_to); - break; - case EXTABLE_TO_NON_TEXT: - fatal("There's a special handler for this mismatch type, " - "we should never get here."); - break; - } - fprintf(stderr, "\n"); -} - -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) -{ - const char *tosec; - Elf_Sym *to; - Elf_Sym *from; - const char *tosym; - const char *fromsym; - - from = find_elf_symbol2(elf, r->r_offset, fromsec); - fromsym = sym_name(elf, from); - - if (strstarts(fromsym, "reference___initcall")) - return; - - tosec = sec_name(elf, get_secindex(elf, sym)); - to = find_elf_symbol(elf, r->r_addend, sym); - tosym = sym_name(elf, to); - - /* check whitelist - we may ignore it */ - if (secref_whitelist(mismatch, - fromsec, fromsym, tosec, tosym)) { - report_sec_mismatch(modname, mismatch, - fromsec, r->r_offset, fromsym, - is_function(from), tosec, tosym, - is_function(to)); - } -} - -static int is_executable_section(struct elf_info* elf, unsigned int section_index) -{ - if (section_index > elf->num_sections) - fatal("section_index is outside elf->num_sections!\n"); - - return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); -} - -/* - * 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; -} - -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)); - - sec_mismatch_count++; - - 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); - } -} - -static void check_section_mismatch(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) -{ - const char *tosec = sec_name(elf, get_secindex(elf, sym)); - const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); - - if (mismatch) { - if (mismatch->handler) - mismatch->handler(modname, elf, mismatch, - r, sym, fromsec); - else - default_mismatch_handler(modname, elf, mismatch, - r, sym, fromsec); - } -} - -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); -} - -static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, 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: - r->r_addend = TO_NATIVE(*location); - break; - case R_386_PC32: - r->r_addend = TO_NATIVE(*location) + 4; - /* For CONFIG_RELOCATABLE=y */ - if (elf->hdr->e_type == ET_EXEC) - r->r_addend += r->r_offset; - break; - } - return 0; -} - -#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_THM_JUMP19 -#define R_ARM_THM_JUMP19 51 -#endif - -static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) -{ - unsigned int r_typ = ELF_R_TYPE(r->r_info); - - switch (r_typ) { - case R_ARM_ABS32: - /* From ARM ABI: (S + A) | T */ - r->r_addend = (int)(long) - (elf->symtab_start + ELF_R_SYM(r->r_info)); - break; - case R_ARM_PC24: - case R_ARM_CALL: - case R_ARM_JUMP24: - 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)); - break; - default: - return 1; - } - return 0; -} - -static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) -{ - unsigned int r_typ = ELF_R_TYPE(r->r_info); - unsigned int *location = reloc_location(elf, sechdr, r); - unsigned int inst; - - if (r_typ == R_MIPS_HI16) - return 1; /* skip this */ - inst = TO_NATIVE(*location); - switch (r_typ) { - case R_MIPS_LO16: - r->r_addend = inst & 0xffff; - break; - case R_MIPS_26: - r->r_addend = (inst & 0x03ffffff) << 2; - break; - case R_MIPS_32: - r->r_addend = inst; - break; - } - return 0; -} - -#ifndef EM_RISCV -#define EM_RISCV 243 -#endif - -#ifndef R_RISCV_SUB32 -#define R_RISCV_SUB32 39 -#endif - -static void section_rela(const char *modname, struct elf_info *elf, - Elf_Shdr *sechdr) -{ - Elf_Sym *sym; - Elf_Rela *rela; - Elf_Rela r; - unsigned int r_sym; - const char *fromsec; - - Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; - Elf_Rela *stop = (void *)start + sechdr->sh_size; - - fromsec = sech_name(elf, sechdr); - fromsec += strlen(".rela"); - /* if from section (name) is know good then skip it */ - if (match(fromsec, section_white_list)) - return; - - for (rela = start; rela < stop; rela++) { - r.r_offset = TO_NATIVE(rela->r_offset); -#if KERNEL_ELFCLASS == ELFCLASS64 - if (elf->hdr->e_machine == EM_MIPS) { - unsigned int r_typ; - r_sym = ELF64_MIPS_R_SYM(rela->r_info); - r_sym = TO_NATIVE(r_sym); - r_typ = ELF64_MIPS_R_TYPE(rela->r_info); - r.r_info = ELF64_R_INFO(r_sym, r_typ); - } else { - r.r_info = TO_NATIVE(rela->r_info); - r_sym = ELF_R_SYM(r.r_info); - } -#else - r.r_info = TO_NATIVE(rela->r_info); - r_sym = ELF_R_SYM(r.r_info); -#endif - r.r_addend = TO_NATIVE(rela->r_addend); - switch (elf->hdr->e_machine) { - case EM_RISCV: - if (!strcmp("__ex_table", fromsec) && - ELF_R_TYPE(r.r_info) == R_RISCV_SUB32) - 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); - } -} - -static void section_rel(const char *modname, struct elf_info *elf, - Elf_Shdr *sechdr) -{ - Elf_Sym *sym; - Elf_Rel *rel; - Elf_Rela r; - unsigned int r_sym; - const char *fromsec; - - Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; - Elf_Rel *stop = (void *)start + sechdr->sh_size; - - fromsec = sech_name(elf, sechdr); - fromsec += strlen(".rel"); - /* if from section (name) is know good then skip it */ - if (match(fromsec, section_white_list)) - return; - - for (rel = start; rel < stop; rel++) { - r.r_offset = TO_NATIVE(rel->r_offset); -#if KERNEL_ELFCLASS == ELFCLASS64 - if (elf->hdr->e_machine == EM_MIPS) { - unsigned int r_typ; - r_sym = ELF64_MIPS_R_SYM(rel->r_info); - r_sym = TO_NATIVE(r_sym); - r_typ = ELF64_MIPS_R_TYPE(rel->r_info); - r.r_info = ELF64_R_INFO(r_sym, r_typ); - } else { - r.r_info = TO_NATIVE(rel->r_info); - r_sym = ELF_R_SYM(r.r_info); - } -#else - r.r_info = TO_NATIVE(rel->r_info); - r_sym = ELF_R_SYM(r.r_info); -#endif - r.r_addend = 0; - switch (elf->hdr->e_machine) { - case EM_386: - if (addend_386_rel(elf, sechdr, &r)) - continue; - break; - case EM_ARM: - if (addend_arm_rel(elf, sechdr, &r)) - continue; - break; - case EM_MIPS: - if (addend_mips_rel(elf, sechdr, &r)) - 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, rel, fromsec)) - find_extable_entry_size(fromsec, &r); - check_section_mismatch(modname, elf, &r, sym, fromsec); - } -} - -/** - * 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, const char *modname, - 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]); - /* We want to process only relocation sections and not .init */ - if (sechdrs[i].sh_type == SHT_RELA) - section_rela(modname, elf, &elf->sechdrs[i]); - else if (sechdrs[i].sh_type == SHT_REL) - section_rel(modname, elf, &elf->sechdrs[i]); - } -} - static char *remove_dot(char *s) { size_t n = strcspn(s, "."); diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index d9daeff07b83..ffa4512e992f 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -52,28 +52,6 @@ #define ELF_R_TYPE ELF64_R_TYPE #endif -/* The 64-bit MIPS ELF ABI uses an unusual reloc format. */ -typedef struct -{ - Elf32_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_type1; /* 1st relocation type */ -} _Elf64_Mips_R_Info; - -typedef union -{ - Elf64_Xword r_info_number; - _Elf64_Mips_R_Info r_info_fields; -} _Elf64_Mips_R_Info_union; - -#define ELF64_MIPS_R_SYM(i) \ - ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_sym) - -#define ELF64_MIPS_R_TYPE(i) \ - ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_type1) - #if KERNEL_ELFDATA != HOST_ELFDATA static inline void __endian(const void *src, void *dest, unsigned int size) @@ -96,6 +74,7 @@ static inline void __endian(const void *src, void *dest, unsigned int size) #endif +#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) #define NOFAIL(ptr) do_nofail((ptr), #ptr) void *do_nofail(void *ptr, const char *expr); @@ -173,6 +152,10 @@ static inline unsigned int get_secindex(const struct elf_info *info, return info->symtab_shndx_start[sym - info->symtab_start]; } +/* section-check.c */ +void check_sec_ref(struct module *mod, const char *modname, + struct elf_info *elf); + /* file2alias.c */ void handle_moddevtable(struct module *mod, struct elf_info *info, Elf_Sym *sym, const char *symname); @@ -182,6 +165,13 @@ void add_moddevtable(struct buffer *buf, struct module *mod); void get_src_version(const char *modname, char sum[], unsigned sumlen); /* from modpost.c */ +extern int sec_mismatch_count; + +void *sym_get_data_by_offset(const struct elf_info *info, + unsigned int secindex, unsigned long offset); +const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr); +const char *sec_name(const struct elf_info *info, int secindex); + char *read_text_file(const char *filename); char *get_line(char **stringp); diff --git a/scripts/mod/section-check.c b/scripts/mod/section-check.c new file mode 100644 index 000000000000..c7467fe9af74 --- /dev/null +++ b/scripts/mod/section-check.c @@ -0,0 +1,1222 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2006-2008 Sam Ravnborg + */ + +#include +#include +#include + +#include "modpost.h" + +/* The 64-bit MIPS ELF ABI uses an unusual reloc format. */ +typedef struct +{ + Elf32_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_type1; /* 1st relocation type */ +} _Elf64_Mips_R_Info; + +typedef union +{ + Elf64_Xword r_info_number; + _Elf64_Mips_R_Info r_info_fields; +} _Elf64_Mips_R_Info_union; + +#define ELF64_MIPS_R_SYM(i) \ + ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_sym) + +#define ELF64_MIPS_R_TYPE(i) \ + ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_type1) + +/** + * Test if string s ends in string sub + * return 0 if match + **/ +static int strrcmp(const char *s, const char *sub) +{ + int slen, sublen; + + if (!s || !sub) + return 1; + + slen = strlen(s); + sublen = strlen(sub); + + if ((slen == 0) || (sublen == 0)) + return 1; + + if (sublen > slen) + return 1; + + return memcmp(s + slen - sublen, sub, sublen); +} + +static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) +{ + if (sym) + return elf->strtab + sym->st_name; + else + return "(unknown)"; +} + +/* The pattern is an array of simple patterns. + * "foo" will match an exact string equal to "foo" + * "*foo" will match a string that ends with "foo" + * "foo*" will match a string that begins with "foo" + * "*foo*" will match a string that contains "foo" + */ +static int match(const char *sym, const char * const pat[]) +{ + const char *p; + while (*pat) { + const char *endp; + + p = *pat++; + endp = p + strlen(p) - 1; + + /* "*foo*" */ + if (*p == '*' && *endp == '*') { + char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2)); + char *here = strstr(sym, bare); + + free(bare); + if (here != NULL) + return 1; + } + /* "*foo" */ + else if (*p == '*') { + if (strrcmp(sym, p + 1) == 0) + return 1; + } + /* "foo*" */ + else if (*endp == '*') { + if (strncmp(sym, p, strlen(p) - 1) == 0) + return 1; + } + /* no wildcards */ + else { + if (strcmp(p, sym) == 0) + return 1; + } + } + /* no match */ + return 0; +} + +/* sections that we do not want to do full section mismatch check on */ +static const char *const section_white_list[] = +{ + ".comment*", + ".debug*", + ".cranges", /* sh64 */ + ".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.*", + 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_EXIT_DATA_SECTIONS \ + ".exit.data", ".memexit.data" + +#define ALL_INIT_TEXT_SECTIONS \ + ".init.text", ".meminit.text" +#define ALL_EXIT_TEXT_SECTIONS \ + ".exit.text", ".memexit.text" + +#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 MEM_INIT_SECTIONS +#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS + +#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS +#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS + +#define DATA_SECTIONS ".data", ".data.rel" +#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ + ".kprobes.text", ".cpuidle.text", ".noinstr.text" +#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ + ".fixup", ".entry.text", ".exception.text", ".text.*", \ + ".coldtext", ".softirqentry.text" + +#define INIT_SECTIONS ".init.*" +#define MEM_INIT_SECTIONS ".meminit.*" + +#define EXIT_SECTIONS ".exit.*" +#define MEM_EXIT_SECTIONS ".memexit.*" + +#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 init and exit sections (code + data) */ +static const char *const init_exit_sections[] = + {ALL_INIT_SECTIONS, ALL_EXIT_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 }; + + +/* symbols in .data that may refer to init/exit sections */ +#define DEFAULT_SYMBOL_WHITE_LIST \ + "*driver", \ + "*_template", /* scsi uses *_template a lot */ \ + "*_timer", /* arm uses ops structures named _timer a lot */ \ + "*_sht", /* scsi also used *_sht to some extent */ \ + "*_ops", \ + "*_probe", \ + "*_probe_one", \ + "*_console" + +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, + 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, +}; + +/** + * 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. + * + * @symbol_white_list: Do not match a relocation to a symbol in this list + * even if it is targeting a section in @bad_to_sec. + * + * @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; + const char *symbol_white_list[20]; + 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 + */ +{ + .fromsec = { TEXT_SECTIONS, NULL }, + .bad_tosec = { ALL_INIT_SECTIONS, NULL }, + .mismatch = TEXT_TO_ANY_INIT, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +{ + .fromsec = { DATA_SECTIONS, NULL }, + .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, + .mismatch = DATA_TO_ANY_INIT, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +{ + .fromsec = { DATA_SECTIONS, NULL }, + .bad_tosec = { INIT_SECTIONS, NULL }, + .mismatch = DATA_TO_ANY_INIT, + .symbol_white_list = { + "*_template", "*_timer", "*_sht", "*_ops", + "*_probe", "*_probe_one", "*_console", NULL + }, +}, +{ + .fromsec = { TEXT_SECTIONS, NULL }, + .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, + .mismatch = TEXT_TO_ANY_EXIT, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +{ + .fromsec = { DATA_SECTIONS, NULL }, + .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, + .mismatch = DATA_TO_ANY_EXIT, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +/* 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, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +/* Do not reference exit code/data from memexit code/data */ +{ + .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, + .bad_tosec = { EXIT_SECTIONS, NULL }, + .mismatch = XXXEXIT_TO_SOME_EXIT, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +/* 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, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +/* 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, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +{ + .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, + .bad_tosec = { INIT_SECTIONS, NULL }, + .mismatch = ANY_INIT_TO_ANY_EXIT, + .symbol_white_list = { NULL }, +}, +/* Do not export init/exit functions or data */ +{ + .fromsec = { "__ksymtab*", NULL }, + .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, + .mismatch = EXPORT_TO_INIT_EXIT, + .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +{ + .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, + .handler = extable_mismatch_handler, +} +}; + +static const struct sectioncheck *section_mismatch( + const char *fromsec, const char *tosec) +{ + int i; + int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck); + const struct sectioncheck *check = §ioncheck[0]; + + /* + * 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 < elems; 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; + } + 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 2: + * Many drivers utilise a *driver container with references to + * add, remove, probe functions etc. + * the pattern is identified by: + * tosec = init or exit section + * fromsec = data section + * atsym = *driver, *_template, *_sht, *_ops, *_probe, + * *probe_one, *_console, *_timer + * + * Pattern 3: + * Whitelist all 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.* + * + * 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, + const char *tosec, const char *tosym) +{ + /* Check for pattern 1 */ + if (match(tosec, init_data_sections) && + match(fromsec, data_sections) && + strstarts(fromsym, "__param")) + return 0; + + /* Check for pattern 1a */ + if (strcmp(tosec, ".init.text") == 0 && + match(fromsec, data_sections) && + strstarts(fromsym, "__param_ops_")) + return 0; + + /* Check for pattern 2 */ + if (match(tosec, init_exit_sections) && + match(fromsec, data_sections) && + match(fromsym, mismatch->symbol_white_list)) + return 0; + + /* Check for pattern 3 */ + if (match(fromsec, head_sections) && + match(tosec, init_sections)) + return 0; + + /* Check for pattern 4 */ + if (match(tosym, linker_symbols)) + 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")) + return 0; + + return 1; +} + +static inline int is_arm_mapping_symbol(const char *str) +{ + return str[0] == '$' && strchr("axtd", str[1]) + && (str[2] == '\0' || str[2] == '.'); +} + +/* + * If there's no name there, ignore it; likewise, ignore it if it's + * one of the magic symbols emitted used by current ARM tools. + * + * Otherwise if find_symbols_between() returns those symbols, they'll + * fail the whitelist tests and cause lots of false alarms ... fixable + * only by merging __exit and __init sections into __text, bloating + * the kernel (which is especially evil on embedded platforms). + */ +static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) +{ + const char *name = elf->strtab + sym->st_name; + + if (!name || !strlen(name)) + return 0; + return !is_arm_mapping_symbol(name); +} + +/** + * Find 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) +{ + 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; + + 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) + 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; + + for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { + const char *symsec; + + 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)) + continue; + if (sym->st_value <= addr) { + if ((addr - sym->st_value) < distance) { + distance = addr - sym->st_value; + near = sym; + } else if ((addr - sym->st_value) == distance) { + near = sym; + } + } + } + return near; +} + +/* + * Convert a section name to the function/data attribute + * .init.text => __init + * .memexitconst => __memconst + * etc. + * + * The memory of returned value has been allocated on a heap. The user of this + * method should free it after usage. +*/ +static char *sec2annotation(const char *s) +{ + if (match(s, init_exit_sections)) { + char *p = NOFAIL(malloc(20)); + char *r = p; + + *p++ = '_'; + *p++ = '_'; + if (*s == '.') + s++; + while (*s && *s != '.') + *p++ = *s++; + *p = '\0'; + if (*s == '.') + s++; + if (strstr(s, "rodata") != NULL) + strcat(p, "const "); + else if (strstr(s, "data") != NULL) + strcat(p, "data "); + else + strcat(p, " "); + return r; + } else { + return NOFAIL(strdup("")); + } +} + +static int is_function(Elf_Sym *sym) +{ + if (sym) + return ELF_ST_TYPE(sym->st_info) == STT_FUNC; + else + return -1; +} + +static void print_section_list(const char * const list[20]) +{ + const char *const *s = list; + + while (*s) { + fprintf(stderr, "%s", *s); + s++; + if (*s) + fprintf(stderr, ", "); + } + fprintf(stderr, "\n"); +} + +static inline void get_pretty_name(int is_func, const char** name, const char** name_p) +{ + switch (is_func) { + case 0: *name = "variable"; *name_p = ""; break; + case 1: *name = "function"; *name_p = "()"; break; + default: *name = "(unknown reference)"; *name_p = ""; break; + } +} + +/* + * 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, + unsigned long long fromaddr, + const char *fromsym, + int from_is_func, + const char *tosec, const char *tosym, + int to_is_func) +{ + const char *from, *from_p; + const char *to, *to_p; + char *prl_from; + char *prl_to; + + sec_mismatch_count++; + + get_pretty_name(from_is_func, &from, &from_p); + get_pretty_name(to_is_func, &to, &to_p); + + warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " + "to the %s %s:%s%s\n", + modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, + tosym, to_p); + + switch (mismatch->mismatch) { + case TEXT_TO_ANY_INIT: + prl_from = sec2annotation(fromsec); + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The function %s%s() references\n" + "the %s %s%s%s.\n" + "This is often because %s lacks a %s\n" + "annotation or the annotation of %s is wrong.\n", + prl_from, fromsym, + to, prl_to, tosym, to_p, + fromsym, prl_to, tosym); + free(prl_from); + free(prl_to); + break; + case DATA_TO_ANY_INIT: { + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The variable %s references\n" + "the %s %s%s%s\n" + "If the reference is valid then annotate the\n" + "variable with __init* or __refdata (see linux/init.h) " + "or name the variable:\n", + fromsym, to, prl_to, tosym, to_p); + print_section_list(mismatch->symbol_white_list); + free(prl_to); + break; + } + case TEXT_TO_ANY_EXIT: + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The function %s() references a %s in an exit section.\n" + "Often the %s %s%s has valid usage outside the exit section\n" + "and the fix is to remove the %sannotation of %s.\n", + fromsym, to, to, tosym, to_p, prl_to, tosym); + free(prl_to); + break; + case DATA_TO_ANY_EXIT: { + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The variable %s references\n" + "the %s %s%s%s\n" + "If the reference is valid then annotate the\n" + "variable with __exit* (see linux/init.h) or " + "name the variable:\n", + fromsym, to, prl_to, tosym, to_p); + print_section_list(mismatch->symbol_white_list); + free(prl_to); + break; + } + case XXXINIT_TO_SOME_INIT: + case XXXEXIT_TO_SOME_EXIT: + prl_from = sec2annotation(fromsec); + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The %s %s%s%s references\n" + "a %s %s%s%s.\n" + "If %s is only used by %s then\n" + "annotate %s with a matching annotation.\n", + from, prl_from, fromsym, from_p, + to, prl_to, tosym, to_p, + tosym, fromsym, tosym); + free(prl_from); + free(prl_to); + break; + case ANY_INIT_TO_ANY_EXIT: + prl_from = sec2annotation(fromsec); + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The %s %s%s%s references\n" + "a %s %s%s%s.\n" + "This is often seen when error handling " + "in the init function\n" + "uses functionality in the exit path.\n" + "The fix is often to remove the %sannotation of\n" + "%s%s so it may be used outside an exit section.\n", + from, prl_from, fromsym, from_p, + to, prl_to, tosym, to_p, + prl_to, tosym, to_p); + free(prl_from); + free(prl_to); + break; + case ANY_EXIT_TO_ANY_INIT: + prl_from = sec2annotation(fromsec); + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The %s %s%s%s references\n" + "a %s %s%s%s.\n" + "This is often seen when error handling " + "in the exit function\n" + "uses functionality in the init path.\n" + "The fix is often to remove the %sannotation of\n" + "%s%s so it may be used outside an init section.\n", + from, prl_from, fromsym, from_p, + to, prl_to, tosym, to_p, + prl_to, tosym, to_p); + free(prl_from); + free(prl_to); + break; + case EXPORT_TO_INIT_EXIT: + prl_to = sec2annotation(tosec); + fprintf(stderr, + "The symbol %s is exported and annotated %s\n" + "Fix this by removing the %sannotation of %s " + "or drop the export.\n", + tosym, prl_to, prl_to, tosym); + free(prl_to); + break; + case EXTABLE_TO_NON_TEXT: + fatal("There's a special handler for this mismatch type, " + "we should never get here."); + break; + } + fprintf(stderr, "\n"); +} + +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) +{ + const char *tosec; + Elf_Sym *to; + Elf_Sym *from; + const char *tosym; + const char *fromsym; + + from = find_elf_symbol2(elf, r->r_offset, fromsec); + fromsym = sym_name(elf, from); + + if (strstarts(fromsym, "reference___initcall")) + return; + + tosec = sec_name(elf, get_secindex(elf, sym)); + to = find_elf_symbol(elf, r->r_addend, sym); + tosym = sym_name(elf, to); + + /* check whitelist - we may ignore it */ + if (secref_whitelist(mismatch, + fromsec, fromsym, tosec, tosym)) { + report_sec_mismatch(modname, mismatch, + fromsec, r->r_offset, fromsym, + is_function(from), tosec, tosym, + is_function(to)); + } +} + +static int is_executable_section(struct elf_info* elf, unsigned int section_index) +{ + if (section_index > elf->num_sections) + fatal("section_index is outside elf->num_sections!\n"); + + return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); +} + +/* + * 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; +} + +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)); + + sec_mismatch_count++; + + 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); + } +} + +static void check_section_mismatch(const char *modname, struct elf_info *elf, + Elf_Rela *r, Elf_Sym *sym, const char *fromsec) +{ + const char *tosec = sec_name(elf, get_secindex(elf, sym)); + const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); + + if (mismatch) { + if (mismatch->handler) + mismatch->handler(modname, elf, mismatch, + r, sym, fromsec); + else + default_mismatch_handler(modname, elf, mismatch, + r, sym, fromsec); + } +} + +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); +} + +static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, 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: + r->r_addend = TO_NATIVE(*location); + break; + case R_386_PC32: + r->r_addend = TO_NATIVE(*location) + 4; + /* For CONFIG_RELOCATABLE=y */ + if (elf->hdr->e_type == ET_EXEC) + r->r_addend += r->r_offset; + break; + } + return 0; +} + +#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_THM_JUMP19 +#define R_ARM_THM_JUMP19 51 +#endif + +static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +{ + unsigned int r_typ = ELF_R_TYPE(r->r_info); + + switch (r_typ) { + case R_ARM_ABS32: + /* From ARM ABI: (S + A) | T */ + r->r_addend = (int)(long) + (elf->symtab_start + ELF_R_SYM(r->r_info)); + break; + case R_ARM_PC24: + case R_ARM_CALL: + case R_ARM_JUMP24: + 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)); + break; + default: + return 1; + } + return 0; +} + +static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) +{ + unsigned int r_typ = ELF_R_TYPE(r->r_info); + unsigned int *location = reloc_location(elf, sechdr, r); + unsigned int inst; + + if (r_typ == R_MIPS_HI16) + return 1; /* skip this */ + inst = TO_NATIVE(*location); + switch (r_typ) { + case R_MIPS_LO16: + r->r_addend = inst & 0xffff; + break; + case R_MIPS_26: + r->r_addend = (inst & 0x03ffffff) << 2; + break; + case R_MIPS_32: + r->r_addend = inst; + break; + } + return 0; +} + +#ifndef EM_RISCV +#define EM_RISCV 243 +#endif + +#ifndef R_RISCV_SUB32 +#define R_RISCV_SUB32 39 +#endif + +static void section_rela(const char *modname, struct elf_info *elf, + Elf_Shdr *sechdr) +{ + Elf_Sym *sym; + Elf_Rela *rela; + Elf_Rela r; + unsigned int r_sym; + const char *fromsec; + + Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; + Elf_Rela *stop = (void *)start + sechdr->sh_size; + + fromsec = sech_name(elf, sechdr); + fromsec += strlen(".rela"); + /* if from section (name) is know good then skip it */ + if (match(fromsec, section_white_list)) + return; + + for (rela = start; rela < stop; rela++) { + r.r_offset = TO_NATIVE(rela->r_offset); +#if KERNEL_ELFCLASS == ELFCLASS64 + if (elf->hdr->e_machine == EM_MIPS) { + unsigned int r_typ; + r_sym = ELF64_MIPS_R_SYM(rela->r_info); + r_sym = TO_NATIVE(r_sym); + r_typ = ELF64_MIPS_R_TYPE(rela->r_info); + r.r_info = ELF64_R_INFO(r_sym, r_typ); + } else { + r.r_info = TO_NATIVE(rela->r_info); + r_sym = ELF_R_SYM(r.r_info); + } +#else + r.r_info = TO_NATIVE(rela->r_info); + r_sym = ELF_R_SYM(r.r_info); +#endif + r.r_addend = TO_NATIVE(rela->r_addend); + switch (elf->hdr->e_machine) { + case EM_RISCV: + if (!strcmp("__ex_table", fromsec) && + ELF_R_TYPE(r.r_info) == R_RISCV_SUB32) + 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); + } +} + +static void section_rel(const char *modname, struct elf_info *elf, + Elf_Shdr *sechdr) +{ + Elf_Sym *sym; + Elf_Rel *rel; + Elf_Rela r; + unsigned int r_sym; + const char *fromsec; + + Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; + Elf_Rel *stop = (void *)start + sechdr->sh_size; + + fromsec = sech_name(elf, sechdr); + fromsec += strlen(".rel"); + /* if from section (name) is know good then skip it */ + if (match(fromsec, section_white_list)) + return; + + for (rel = start; rel < stop; rel++) { + r.r_offset = TO_NATIVE(rel->r_offset); +#if KERNEL_ELFCLASS == ELFCLASS64 + if (elf->hdr->e_machine == EM_MIPS) { + unsigned int r_typ; + r_sym = ELF64_MIPS_R_SYM(rel->r_info); + r_sym = TO_NATIVE(r_sym); + r_typ = ELF64_MIPS_R_TYPE(rel->r_info); + r.r_info = ELF64_R_INFO(r_sym, r_typ); + } else { + r.r_info = TO_NATIVE(rel->r_info); + r_sym = ELF_R_SYM(r.r_info); + } +#else + r.r_info = TO_NATIVE(rel->r_info); + r_sym = ELF_R_SYM(r.r_info); +#endif + r.r_addend = 0; + switch (elf->hdr->e_machine) { + case EM_386: + if (addend_386_rel(elf, sechdr, &r)) + continue; + break; + case EM_ARM: + if (addend_arm_rel(elf, sechdr, &r)) + continue; + break; + case EM_MIPS: + if (addend_mips_rel(elf, sechdr, &r)) + 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, rel, fromsec)) + find_extable_entry_size(fromsec, &r); + check_section_mismatch(modname, elf, &r, sym, fromsec); + } +} + +/** + * 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. + **/ +void check_sec_ref(struct module *mod, const char *modname, + 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]); + /* We want to process only relocation sections and not .init */ + if (sechdrs[i].sh_type == SHT_RELA) + section_rela(modname, elf, &elf->sechdrs[i]); + else if (sechdrs[i].sh_type == SHT_REL) + section_rel(modname, elf, &elf->sechdrs[i]); + } +} From patchwork Wed May 11 16:45:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846476 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E858C433FE for ; Wed, 11 May 2022 16:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243630AbiEKQts (ORCPT ); Wed, 11 May 2022 12:49:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345031AbiEKQtq (ORCPT ); Wed, 11 May 2022 12:49:46 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5911C95DE8; Wed, 11 May 2022 09:49:42 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWbv031975; Thu, 12 May 2022 01:47:35 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWbv031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287655; bh=nPFeNb7zcOn5IuqqOUBw3aAC983zUVDbQ5TFg7R+mlQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gkESwt0tgX74oapFqHSCwWI/Bk8Ad4YZ8SrAbF7yZTsg2uxWwzhaWocVBJyzR0cnk 0K/qmOJdf1rNWwm3+EJQgBN7lGD+/6KmK6ukb613+nVKaNI20dpP2i/pC0oei1N8lW nYcbSUfk0eUbIhd6kmm1elHieqjRN8kXKOn1E2408ZMc+BLwrqRCYOqh/tZLiRC+gk /QasUWfa/8wjt0WSJZv8yk3rEk2IwA7c6zZCKPe7Iwso0wrfwuzjhDpsmggvTA0bXF 0ofYM6whQAGxcha+sJpZZ+XVltmAPe+wJyQuvYnK9krcypZso6n2TCvfol7/h+YrpJ m7fjJTaJN6h1g== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 02/12] modpost: add sym_find_with_module() helper Date: Thu, 12 May 2022 01:45:04 +0900 Message-Id: <20220511164514.2741934-3-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: find_symbol() returns the first symbol found in the hash table. This table is global, so it may return a symbol from an unexpected module. There is a case where we want to search for a symbol with a given name in a specified module. Add sym_find_with_module(), which receives the module pointer as the second argument. It is equivalent to find_module() if NULL is passed as the module pointer. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor --- (no changes since v4) Changes in v4: - Only takes the new helper from https://patchwork.kernel.org/project/linux-kbuild/patch/20220505072244.1155033-2-masahiroy@kernel.org/ Changes in v2: - Rename the new func to sym_find_with_module() scripts/mod/modpost.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index e7e2c70a98f5..fc5db1f73cf1 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -266,7 +266,7 @@ static void sym_add_unresolved(const char *name, struct module *mod, bool weak) list_add_tail(&sym->list, &mod->unresolved_symbols); } -static struct symbol *find_symbol(const char *name) +static struct symbol *sym_find_with_module(const char *name, struct module *mod) { struct symbol *s; @@ -275,12 +275,17 @@ static struct symbol *find_symbol(const char *name) name++; for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) { - if (strcmp(s->name, name) == 0) + 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[]; From patchwork Wed May 11 16:45:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846477 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2C6DC4167B for ; Wed, 11 May 2022 16:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345058AbiEKQtt (ORCPT ); Wed, 11 May 2022 12:49:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345037AbiEKQtr (ORCPT ); Wed, 11 May 2022 12:49:47 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58F6195DE7; Wed, 11 May 2022 09:49:43 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWbw031975; Thu, 12 May 2022 01:47:36 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWbw031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287656; bh=K2QFhIzFr8Ryt23lgpW/N278Pugm1HvnJajATX6+Xpc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZBSxRbjmxaVnmMhoVGQQTb1fZLsI8N8BqgzAEedwFpVRKqKykRASjt0d2bouv3fGH jsasg0nUJRjDgA0GmpMUz2CZJCmNFV3ZuGLJmWUUfV1YWg4aSFWudA7XMnTr8WO7r0 MmXqmUeNM3GkELT57OLZsWOXnfcomBqvROGfuommqmSMNJkQz1cMt/90x066W/+1xS w1oudaP7Oq8AeFWDwJQbxemfKri53yH6MEDSH4jEgGdGcaEy8P0XHycr4DdgSPLw+0 AzB6KjdWnZlofvSzNFj0JRxT1G34qG3KantZ42E345FNn4ouZK2B1xB9/wtx0b6T69 Wq7rPhgw7kz9A== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 03/12] modpost: extract symbol versions from *.cmd files Date: Thu, 12 May 2022 01:45:05 +0900 Message-Id: <20220511164514.2741934-4-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: Currently, CONFIG_MODVERSIONS needs extra link to embed the symbol versions into ELF objects. Then, modpost extracts the version CRCs from them. The following figures show how it currently works, and how I am trying to change it. Current implementation ====================== |----------| embed CRC -------------------------->| final | $(CC) $(LD) / |---------| | link for | -----> *.o -------> *.o -->| modpost | | vmlinux | / / | |-- *.mod.c -->| or | / genksyms / |---------| | module | *.c ------> *.symversions |----------| Genksyms outputs the calculated CRCs in the form of linker script (*.symversions), which is used by $(LD) to update the object. If CONFIG_LTO_CLANG=y, the build process is much more complex. Embedding the CRCs is postponed until the LLVM bitcode is converted into ELF, creating another intermediate *.prelink.o. However, this complexity is unneeded. There is no reason why we must embed version CRCs in objects so early. There is final link stage for vmlinux (scripts/link-vmlinux.sh) and modules (scripts/Makefile.modfinal). We can link CRCs at the very last moment. New implementation ================== |----------| --------------------------------------->| final | $(CC) / |---------| | link for | -----> *.o ---->| | | vmlinux | / | modpost |--- .vmlinux.export.c -->| or | / genksyms | |--- *.mod.c ------------>| module | *.c ------> *.cmd -->|---------| |----------| Pass the symbol versions to modpost as separate text data, which are available in *.cmd files. This commit changes modpost to extract CRCs from *.cmd files instead of from ELF objects. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor Reviewed-by: Sami Tolvanen --- (no changes since v2) Changes in v2: - Simplify the implementation (parse .cmd files after ELF) scripts/mod/modpost.c | 177 ++++++++++++++++++++++++++++++------------ 1 file changed, 129 insertions(+), 48 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index fc5db1f73cf1..e0f9c02d9f83 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -381,19 +381,10 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, return s; } -static void sym_set_crc(const char *name, unsigned int crc) +static void sym_set_crc(struct symbol *sym, unsigned int crc) { - struct symbol *s = find_symbol(name); - - /* - * Ignore stand-alone __crc_*, which might be auto-generated symbols - * such as __*_veneer in ARM ELF. - */ - if (!s) - return; - - s->crc = crc; - s->crc_valid = true; + sym->crc = crc; + sym->crc_valid = true; } static void *grab_file(const char *filename, size_t *size) @@ -616,33 +607,6 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname) return 0; } -static void handle_modversion(const struct module *mod, - const struct elf_info *info, - const Elf_Sym *sym, const char *symname) -{ - unsigned int crc; - - if (sym->st_shndx == SHN_UNDEF) { - warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n" - "Is \"%s\" prototyped in ?\n", - symname, mod->name, mod->is_vmlinux ? "" : ".ko", - symname); - - return; - } - - if (sym->st_shndx == SHN_ABS) { - crc = sym->st_value; - } else { - unsigned int *crcp; - - /* symbol points to the CRC in the ELF object */ - crcp = sym_get_data(info, sym); - crc = TO_NATIVE(*crcp); - } - sym_set_crc(symname, crc); -} - static void handle_symbol(struct module *mod, struct elf_info *info, const Elf_Sym *sym, const char *symname) { @@ -760,6 +724,102 @@ static char *remove_dot(char *s) 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 = strtol(p, &p, 0); + if (*p != '\n') + continue; /* skip this line */ + + name[namelen] = '\0'; + + sym = sym_find_with_module(name, mod); + if (!sym) { + warn("Skip the version for unexported symbol \"%s\" [%s%s]\n", + name, mod->name, mod->is_vmlinux ? "" : ".ko"); + continue; + } + 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; @@ -820,9 +880,6 @@ static void read_symbols(const char *modname) if (strstarts(symname, "__kstrtabns_")) sym_update_namespace(symname + strlen("__kstrtabns_"), sym_get_data(&info, sym)); - if (strstarts(symname, "__crc_")) - handle_modversion(mod, &info, sym, - symname + strlen("__crc_")); } // check for static EXPORT_SYMBOL_* functions && global vars @@ -850,12 +907,17 @@ static void read_symbols(const char *modname) parse_elf_finish(&info); - /* 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 */ - if (modversions) + 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) @@ -1012,6 +1074,23 @@ static void add_header(struct buffer *b, struct module *mod) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); } +static void check_symversions(struct module *mod) +{ + struct symbol *sym; + + if (!modversions) + return; + + list_for_each_entry(sym, &mod->exported_symbols, list) { + 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); + } + } +} + /** * Record CRCs for unresolved symbols **/ @@ -1227,7 +1306,7 @@ static void read_dump(const char *fname) } s = sym_add_exported(symname, mod, gpl_only); s->is_static = false; - sym_set_crc(symname, crc); + sym_set_crc(s, crc); sym_update_namespace(symname, namespace); } free(buf); @@ -1353,6 +1432,8 @@ int main(int argc, char **argv) if (mod->from_dump) continue; + check_symversions(mod); + if (!mod->is_vmlinux) write_mod_c_file(mod); } From patchwork Wed May 11 16:45:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846480 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 686DEC433F5 for ; Wed, 11 May 2022 16:49:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345088AbiEKQt5 (ORCPT ); Wed, 11 May 2022 12:49:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345046AbiEKQtr (ORCPT ); Wed, 11 May 2022 12:49:47 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C98195DE5; Wed, 11 May 2022 09:49:42 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWbx031975; Thu, 12 May 2022 01:47:37 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWbx031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287657; bh=L3A2vshoUb4rY96va7UNPCkPEL3XgJK/EEqG9km6m0E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2VBl9YjaBqvL+tBQWOk33HbYhdGvMl6yDs8SlvDRQfW42XzZMnKy8vkcb68KxaGuG GWE8RroexYUfMqjgXG4Q9t/aVWBLL6SKOYLJ25sEC4/sAJvmJtboG1ToI1m3N0JRAX Pr8KemoFB5TZzAKwG6umDMqqFgn7Pt5D90tAHy0YM0BTZnr/bf5iCEfc5emKR7IILv o6j5EcPEyugtx3ebLYLH/avRgkNsPcjJ8WfbcbtIO1MbDL3ev5JFbLBdu4mhQ2raof NviBLSdOVsNX1idP4HgrTL2haROiUeruSQ375AJCMNzulJcPSQTt4QsiaEBZY9h7sq 1n+AbYeQ2E3Vg== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 04/12] kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS Date: Thu, 12 May 2022 01:45:06 +0900 Message-Id: <20220511164514.2741934-5-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: include/{linux,asm-generic}/export.h defines a weak symbol, __crc_* as a placeholder. Genksyms writes the version CRCs into the linker script, which will be used for filling the __crc_* symbols. The linker script format depends on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset to the reference of CRC. It is time to get rid of this complexity. Now that modpost parses text files (.*.cmd) to collect all the CRCs, it can generate C code that will be linked to the vmlinux or modules. Generate a new C file, .vmlinux.export.c, which contains the CRCs of symbols exported by vmlinux. It is compiled and linked to vmlinux in scripts/link-vmlinux.sh. Put the CRCs of symbols exported by modules into the existing *.mod.c files. No additional build step is needed for modules. As before, *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal. No linker magic is used here. The new C implementation works in the same way, whether CONFIG_RELOCATABLE is enabled or not. CONFIG_MODULE_REL_CRCS is no longer needed. Previously, Kbuild invoked additional $(LD) to update the CRCs in objects, but this step is unneeded too. Signed-off-by: Masahiro Yamada Tested-by: Nathan Chancellor Tested-by: Nicolas Schier Reviewed-by: Nicolas Schier --- Changes in v5: - Fix the build error when CONFIG_DEBUG_INFO_BTF=y (reported by Nathan) - Clean up arch/m68k/include/asm/export.h (Nick) - Keep gen_symversions (and will be removed by a later patch) Changes in v4: - Rename .vmlinux-symver.c to .vmlinux.export.c because I notice this approach is useful for further cleanups, not only for modversioning but also for overall EXPORT_SYMBOL. Changes in v3: - New patch arch/m68k/include/asm/Kbuild | 1 + arch/m68k/include/asm/export.h | 2 -- arch/powerpc/Kconfig | 1 - arch/s390/Kconfig | 1 - arch/um/Kconfig | 1 - include/asm-generic/export.h | 22 ++++++++-------------- include/linux/export-internal.h | 16 ++++++++++++++++ include/linux/export.h | 30 ++++++++---------------------- init/Kconfig | 4 ---- kernel/module.c | 10 +--------- scripts/Makefile.build | 27 ++++----------------------- scripts/genksyms/genksyms.c | 18 ++++-------------- scripts/link-vmlinux.sh | 14 +++++++++++++- scripts/mod/modpost.c | 28 ++++++++++++++++++++++++---- 14 files changed, 79 insertions(+), 96 deletions(-) delete mode 100644 arch/m68k/include/asm/export.h create mode 100644 include/linux/export-internal.h diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild index 0dbf9c5c6fae..1b720299deb1 100644 --- a/arch/m68k/include/asm/Kbuild +++ b/arch/m68k/include/asm/Kbuild @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 generated-y += syscall_table.h +generic-y += export.h generic-y += extable.h generic-y += kvm_para.h generic-y += mcs_spinlock.h diff --git a/arch/m68k/include/asm/export.h b/arch/m68k/include/asm/export.h deleted file mode 100644 index b53008b67ce1..000000000000 --- a/arch/m68k/include/asm/export.h +++ /dev/null @@ -1,2 +0,0 @@ -#define KCRC_ALIGN 2 -#include diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 174edabb74fa..a4e8dd889e29 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -566,7 +566,6 @@ config RELOCATABLE bool "Build a relocatable kernel" depends on PPC64 || (FLATMEM && (44x || FSL_BOOKE)) select NONSTATIC_KERNEL - select MODULE_REL_CRCS if MODVERSIONS help This builds a kernel image that is capable of running at the location the kernel is loaded at. For ppc32, there is no any diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 77b5a03de13a..aa5848004c76 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -567,7 +567,6 @@ endchoice config RELOCATABLE bool "Build a relocatable kernel" - select MODULE_REL_CRCS if MODVERSIONS default y help This builds a kernel image that retains relocation information diff --git a/arch/um/Kconfig b/arch/um/Kconfig index 4d398b80aea8..e8983d098e73 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -106,7 +106,6 @@ config LD_SCRIPT_DYN bool default y depends on !LD_SCRIPT_STATIC - select MODULE_REL_CRCS if MODVERSIONS config LD_SCRIPT_DYN_RPATH bool "set rpath in the binary" if EXPERT diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 07a36a874dca..5e4b1f2369d2 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -2,6 +2,14 @@ #ifndef __ASM_GENERIC_EXPORT_H #define __ASM_GENERIC_EXPORT_H +/* + * This comment block is used by fixdep. Please do not remove. + * + * When CONFIG_MODVERSIONS is changed from n to y, all source files having + * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a + * side effect of the *.o build rule. + */ + #ifndef KSYM_FUNC #define KSYM_FUNC(x) x #endif @@ -12,9 +20,6 @@ #else #define KSYM_ALIGN 4 #endif -#ifndef KCRC_ALIGN -#define KCRC_ALIGN 4 -#endif .macro __put, val, name #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS @@ -43,17 +48,6 @@ __ksymtab_\name: __kstrtab_\name: .asciz "\name" .previous -#ifdef CONFIG_MODVERSIONS - .section ___kcrctab\sec+\name,"a" - .balign KCRC_ALIGN -#if defined(CONFIG_MODULE_REL_CRCS) - .long __crc_\name - . -#else - .long __crc_\name -#endif - .weak __crc_\name - .previous -#endif #endif .endm diff --git a/include/linux/export-internal.h b/include/linux/export-internal.h new file mode 100644 index 000000000000..77175d561058 --- /dev/null +++ b/include/linux/export-internal.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Please do not include this explicitly. + * This is used by C files generated by modpost. + */ + +#ifndef __LINUX_EXPORT_INTERNAL_H__ +#define __LINUX_EXPORT_INTERNAL_H__ + +#include +#include + +#define SYMBOL_CRC(sym, crc, sec) \ + u32 __section("___kcrctab" sec "+" #sym) __crc_##sym = crc + +#endif /* __LINUX_EXPORT_INTERNAL_H__ */ diff --git a/include/linux/export.h b/include/linux/export.h index 27d848712b90..565c5ffcb26f 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -11,6 +11,14 @@ * hackers place grumpy comments in header files. */ +/* + * This comment block is used by fixdep. Please do not remove. + * + * When CONFIG_MODVERSIONS is changed from n to y, all source files having + * EXPORT_SYMBOL variants must be re-compiled because genksyms is run as a + * side effect of the *.o build rule. + */ + #ifndef __ASSEMBLY__ #ifdef MODULE extern struct module __this_module; @@ -19,26 +27,6 @@ extern struct module __this_module; #define THIS_MODULE ((struct module *)0) #endif -#ifdef CONFIG_MODVERSIONS -/* Mark the CRC weak since genksyms apparently decides not to - * generate a checksums for some symbols */ -#if defined(CONFIG_MODULE_REL_CRCS) -#define __CRC_SYMBOL(sym, sec) \ - asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ - " .weak __crc_" #sym " \n" \ - " .long __crc_" #sym " - . \n" \ - " .previous \n") -#else -#define __CRC_SYMBOL(sym, sec) \ - asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \ - " .weak __crc_" #sym " \n" \ - " .long __crc_" #sym " \n" \ - " .previous \n") -#endif -#else -#define __CRC_SYMBOL(sym, sec) -#endif - #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS #include /* @@ -85,7 +73,6 @@ struct kernel_symbol { /* * For every exported symbol, do the following: * - * - If applicable, place a CRC entry in the __kcrctab section. * - Put the name of the symbol and namespace (empty string "" for none) in * __ksymtab_strings. * - Place a struct kernel_symbol entry in the __ksymtab section. @@ -98,7 +85,6 @@ struct kernel_symbol { extern typeof(sym) sym; \ extern const char __kstrtab_##sym[]; \ extern const char __kstrtabns_##sym[]; \ - __CRC_SYMBOL(sym, sec); \ asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \ "__kstrtab_" #sym ": \n" \ " .asciz \"" #sym "\" \n" \ diff --git a/init/Kconfig b/init/Kconfig index ddcbefe535e9..f5b14318dfcb 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2136,10 +2136,6 @@ config ASM_MODVERSIONS assembly. This can be enabled only when the target architecture supports it. -config MODULE_REL_CRCS - bool - depends on MODVERSIONS - config MODULE_SRCVERSION_ALL bool "Source checksum for all modules" help diff --git a/kernel/module.c b/kernel/module.c index 6cea788fd965..c9e2342da28e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1231,11 +1231,6 @@ static int try_to_force_load(struct module *mod, const char *reason) #ifdef CONFIG_MODVERSIONS -static u32 resolve_rel_crc(const s32 *crc) -{ - return *(u32 *)((void *)crc + *crc); -} - static int check_version(const struct load_info *info, const char *symname, struct module *mod, @@ -1264,10 +1259,7 @@ static int check_version(const struct load_info *info, if (strcmp(versions[i].name, symname) != 0) continue; - if (IS_ENABLED(CONFIG_MODULE_REL_CRCS)) - crcval = resolve_rel_crc(crc); - else - crcval = *crc; + crcval = *crc; if (versions[i].crc == crcval) return 1; pr_debug("Found checksum %X vs module %lX\n", diff --git a/scripts/Makefile.build b/scripts/Makefile.build index a1023868775f..ddd9080fc028 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -128,7 +128,6 @@ $(obj)/%.i: $(src)/%.c FORCE genksyms = scripts/genksyms/genksyms \ $(if $(1), -T $(2)) \ - $(if $(CONFIG_MODULE_REL_CRCS), -R) \ $(if $(KBUILD_PRESERVE), -p) \ -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) @@ -162,19 +161,11 @@ ifdef CONFIG_MODVERSIONS # o if .o doesn't contain a __ksymtab version, i.e. does # not export symbols, it's done. # o otherwise, we calculate symbol versions using the good old -# genksyms on the preprocessed source and postprocess them in a way -# that they are usable as a linker script -# o generate .tmp_.o from .o using the linker to -# replace the unresolved symbols __crc_exported_symbol with -# the actual value of the checksum generated by genksyms -# o remove .tmp_.o to .o +# genksyms on the preprocessed source and dump them into the .cmd file. +# o modpost will extract versions from that file and create *.c files that will +# be compiled and linked to the kernel and/or modules. -# Generate .o.symversions files for each .o with exported symbols, and link these -# to the kernel and/or modules at the end. - -genksyms_format_rel_crc := [^_]*__crc_\([^ ]*\) = \.; LONG(\([^)]*\)).* -genksyms_format_normal := __crc_\(.*\) = \(.*\); -genksyms_format := $(if $(CONFIG_MODULE_REL_CRCS),$(genksyms_format_rel_crc),$(genksyms_format_normal)) +genksyms_format := __crc_\(.*\) = \(.*\); gen_symversions = \ if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ @@ -188,12 +179,6 @@ gen_symversions = \ cmd_gen_symversions_c = $(call gen_symversions,c) -cmd_modversions = \ - if [ -r $@.symversions ]; then \ - $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \ - -T $@.symversions; \ - mv -f $(@D)/.tmp_$(@F) $@; \ - fi endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT @@ -273,7 +258,6 @@ define rule_cc_o_c $(call cmd,checkdoc) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_c) - $(if $(CONFIG_LTO_CLANG),,$(call cmd,modversions)) $(call cmd,record_mcount) endef @@ -282,7 +266,6 @@ define rule_as_o_S $(call cmd,gen_ksymdeps) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) - $(call cmd,modversions) endef # Built-in and composite module parts @@ -296,8 +279,6 @@ ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) quiet_cmd_cc_prelink_modules = LD [M] $@ cmd_cc_prelink_modules = \ $(LD) $(ld_flags) -r -o $@ \ - $(shell [ -s $(@:.prelink.o=.o.symversions) ] && \ - echo -T $(@:.prelink.o=.o.symversions)) \ --whole-archive $(filter-out FORCE,$^) \ $(cmd_objtool) diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c index 4827c5abe5b7..67b23cc0df0f 100644 --- a/scripts/genksyms/genksyms.c +++ b/scripts/genksyms/genksyms.c @@ -33,7 +33,7 @@ char *cur_filename; int in_source_file; static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types, - flag_preserve, flag_warnings, flag_rel_crcs; + flag_preserve, flag_warnings; static int errors; static int nsyms; @@ -680,11 +680,7 @@ void export_symbol(const char *name) if (flag_dump_defs) fputs(">\n", debugfile); - /* Used as a linker script. */ - printf(!flag_rel_crcs ? "__crc_%s = 0x%08lx;\n" : - "SECTIONS { .rodata : ALIGN(4) { " - "__crc_%s = .; LONG(0x%08lx); } }\n", - name, crc); + printf("__crc_%s = 0x%08lx;\n", name, crc); } } @@ -733,7 +729,6 @@ static void genksyms_usage(void) " -q, --quiet Disable warnings (default)\n" " -h, --help Print this message\n" " -V, --version Print the release version\n" - " -R, --relative-crc Emit section relative symbol CRCs\n" #else /* __GNU_LIBRARY__ */ " -s Select symbol prefix\n" " -d Increment the debug level (repeatable)\n" @@ -745,7 +740,6 @@ static void genksyms_usage(void) " -q Disable warnings (default)\n" " -h Print this message\n" " -V Print the release version\n" - " -R Emit section relative symbol CRCs\n" #endif /* __GNU_LIBRARY__ */ , stderr); } @@ -766,14 +760,13 @@ int main(int argc, char **argv) {"preserve", 0, 0, 'p'}, {"version", 0, 0, 'V'}, {"help", 0, 0, 'h'}, - {"relative-crc", 0, 0, 'R'}, {0, 0, 0, 0} }; - while ((o = getopt_long(argc, argv, "s:dwqVDr:T:phR", + while ((o = getopt_long(argc, argv, "s:dwqVDr:T:ph", &long_opts[0], NULL)) != EOF) #else /* __GNU_LIBRARY__ */ - while ((o = getopt(argc, argv, "s:dwqVDr:T:phR")) != EOF) + while ((o = getopt(argc, argv, "s:dwqVDr:T:ph")) != EOF) #endif /* __GNU_LIBRARY__ */ switch (o) { case 'd': @@ -813,9 +806,6 @@ int main(int argc, char **argv) case 'h': genksyms_usage(); return 0; - case 'R': - flag_rel_crcs = 1; - break; default: genksyms_usage(); return 1; diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index eceb3ee7ec06..7313cbd755df 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -90,7 +90,6 @@ modpost_link() if is_enabled CONFIG_MODVERSIONS; then gen_symversions - lds="${lds} -T .tmp_symversions.lds" fi # This might take a while, so indicate that we're doing @@ -183,6 +182,10 @@ vmlinux_link() libs="${KBUILD_VMLINUX_LIBS}" fi + if is_enabled CONFIG_MODULES; then + objs="${objs} .vmlinux.export.o" + fi + if [ "${SRCARCH}" = "um" ]; then wl=-Wl, ld="${CC}" @@ -312,6 +315,7 @@ cleanup() rm -f vmlinux.o rm -f .vmlinux.d rm -f .vmlinux.objs + rm -f .vmlinux.export.c } # Use "make V=1" to debug this script @@ -363,6 +367,14 @@ info GEN modules.builtin tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' | tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin +if is_enabled CONFIG_MODULES; then + info CC .vmlinux.export.c + ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} \ + ${KBUILD_CPPFLAGS} ${KBUILD_CFLAGS} \ + ${KBUILD_CFLAGS_KERNEL} ${CFLAGS_KERNEL} \ + -c -o .vmlinux.export.o .vmlinux.export.c +fi + btf_vmlinux_bin_o="" if is_enabled CONFIG_DEBUG_INFO_BTF; then btf_vmlinux_bin_o=.btf.vmlinux.bin.o diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index e0f9c02d9f83..6b47a8723389 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1040,6 +1040,7 @@ static void add_header(struct buffer *b, struct module *mod) 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"); @@ -1074,20 +1075,26 @@ static void add_header(struct buffer *b, struct module *mod) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); } -static void check_symversions(struct module *mod) +static void add_exported_symbols(struct buffer *buf, struct module *mod) { struct symbol *sym; if (!modversions) return; + /* record CRCs for exported symbols */ + buf_printf(buf, "\n"); list_for_each_entry(sym, &mod->exported_symbols, list) { 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); + continue; } + + buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n", + sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : ""); } } @@ -1224,6 +1231,18 @@ static void write_if_changed(struct buffer *b, const char *fname) 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) { @@ -1235,6 +1254,7 @@ static void write_mod_c_file(struct module *mod) check_exports(mod); add_header(&buf, mod); + add_exported_symbols(&buf, mod); add_versions(&buf, mod); add_depends(&buf, mod); add_moddevtable(&buf, mod); @@ -1432,9 +1452,9 @@ int main(int argc, char **argv) if (mod->from_dump) continue; - check_symversions(mod); - - if (!mod->is_vmlinux) + if (mod->is_vmlinux) + write_vmlinux_export_c_file(mod); + else write_mod_c_file(mod); } From patchwork Wed May 11 16:45:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846479 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D8D0C38A06 for ; Wed, 11 May 2022 16:49:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345064AbiEKQtu (ORCPT ); Wed, 11 May 2022 12:49:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345038AbiEKQtr (ORCPT ); Wed, 11 May 2022 12:49:47 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5936395DE9; Wed, 11 May 2022 09:49:42 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc0031975; Thu, 12 May 2022 01:47:37 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc0031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287658; bh=cga2j3/RnX95UXo6+4HyPv/WWKGxfQZ0xpYK4BVs9G8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GdvD1dXtHHjlc81z6WeX1zZzwaMcqZHFeFqOQLIbP0Gqz0Cn/Q9Q4yURc9g4PlXs4 HimDPcY35Lre7OznD7JTvCHNbJGvJKQCwvxzy0Le8GkxqQaG7oeedg2GxCfwn57754 SikCqgASO1nzN94iVAI2CZaGiaU78q2Xn8QTWyHM8DNOkHRDMi6bcHueuhuMu3gIUN 31TtNTA1QAlZvf/8H7VE7dq4ymlUy0+Vwnwrw1m3F4WmjQSWvIOu7NMolHY5hrBtq2 6N9o2Pwlgw4XwWlVedDtUCmx2AliUCsiCJ1vuVkVW7x+mWMiOL7OK+K9pCoIDunCiU mlzjMcBgavDGQ== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 05/12] kbuild: stop merging *.symversions Date: Thu, 12 May 2022 01:45:07 +0900 Message-Id: <20220511164514.2741934-6-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: Now modpost reads symbol versions from .*.cmd files. The merged *.symversions are no longer needed. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor --- (no changes since v1) scripts/Makefile.build | 21 ++------------------- scripts/link-vmlinux.sh | 19 ------------------- 2 files changed, 2 insertions(+), 38 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index ddd9080fc028..dff9220135c4 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -390,17 +390,6 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler $(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; -# combine symversions for later processing -ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) - cmd_update_lto_symversions = \ - rm -f $@.symversions \ - $(foreach n, $(filter-out FORCE,$^), \ - $(if $(shell test -s $(n).symversions && echo y), \ - ; cat $(n).symversions >> $@.symversions)) -else - cmd_update_lto_symversions = echo >/dev/null -endif - # # Rule to compile a set of .o files into one .a file (without symbol table) # @@ -408,11 +397,8 @@ endif quiet_cmd_ar_builtin = AR $@ cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) -quiet_cmd_ar_and_symver = AR $@ - cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin) - $(obj)/built-in.a: $(real-obj-y) FORCE - $(call if_changed,ar_and_symver) + $(call if_changed,ar_builtin) # # Rule to create modules.order file @@ -432,16 +418,13 @@ $(obj)/modules.order: $(obj-m) FORCE # # Rule to compile a set of .o files into one .a file (with symbol table) # -quiet_cmd_ar_lib = AR $@ - cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar) $(obj)/lib.a: $(lib-y) FORCE - $(call if_changed,ar_lib) + $(call if_changed,ar) ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) quiet_cmd_link_multi-m = AR [M] $@ cmd_link_multi-m = \ - $(cmd_update_lto_symversions); \ rm -f $@; \ $(AR) cDPrsT $@ @$(patsubst %.o,%.mod,$@) else diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 7313cbd755df..47e5336d0c75 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -56,20 +56,6 @@ gen_initcalls() > .tmp_initcalls.lds } -# If CONFIG_LTO_CLANG is selected, collect generated symbol versions into -# .tmp_symversions.lds -gen_symversions() -{ - info GEN .tmp_symversions.lds - rm -f .tmp_symversions.lds - - for o in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do - if [ -f ${o}.symversions ]; then - cat ${o}.symversions >> .tmp_symversions.lds - fi - done -} - # Link of vmlinux.o used for section mismatch analysis # ${1} output file modpost_link() @@ -88,10 +74,6 @@ modpost_link() gen_initcalls lds="-T .tmp_initcalls.lds" - if is_enabled CONFIG_MODVERSIONS; then - gen_symversions - fi - # This might take a while, so indicate that we're doing # an LTO link info LTO ${1} @@ -307,7 +289,6 @@ cleanup() rm -f .btf.* rm -f .tmp_System.map rm -f .tmp_initcalls.lds - rm -f .tmp_symversions.lds rm -f .tmp_vmlinux* rm -f System.map rm -f vmlinux From patchwork Wed May 11 16:45:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846470 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBF03C433EF for ; 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b=WheXMU9GEV/CluE33iXAr7vz1iDk23lqH+YQaVG5VXYoGJV9VsQYDXFzswjBLUAPw mFs/FP6orbudynGzEF6DhFFyDAdUC4HkeOnVG6lCTUjuhzXhU0njrV4QrBq33rgDtZ 4y495WbU1FyN5dtYcOcD3wpTnSZTVW4fehiycOakd9fMA5/NAKOqga6Jyu29QKEQX4 F26o2NUEU1PlHoNpfXJDOIIJlCD2cQ2K34+5d3UToBEffOgK9NdCrhjG+XthkVpjSX j7hF5BsKjpC2Ha5XTE3MWL25pO+MNhAdEAV2Qg8iNoQXn+wnuBf4rBi6Uj5Py9YAUr Bl6quKoN+q4mA== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 06/12] genksyms: adjust the output format to modpost Date: Thu, 12 May 2022 01:45:08 +0900 Message-Id: <20220511164514.2741934-7-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: Make genksyms output symbol versions in the format modpost expects, so the 'sed' is unneeded. This commit makes *.symversions completely unneeded. I will keep *.symversions in .gitignore and 'make clean' for a while. Otherwise, 'git status' might be surprising. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor --- (no changes since v2) Changes in v2: - New patch scripts/Makefile.build | 6 ------ scripts/genksyms/genksyms.c | 2 +- 2 files changed, 1 insertion(+), 7 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index dff9220135c4..461998a2ad2b 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -165,16 +165,10 @@ ifdef CONFIG_MODVERSIONS # o modpost will extract versions from that file and create *.c files that will # be compiled and linked to the kernel and/or modules. -genksyms_format := __crc_\(.*\) = \(.*\); - gen_symversions = \ if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ - > $@.symversions; \ - sed -n 's/$(genksyms_format)/$(pound)SYMVER \1 \2/p' $@.symversions \ >> $(dot-target).cmd; \ - else \ - rm -f $@.symversions; \ fi cmd_gen_symversions_c = $(call gen_symversions,c) diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c index 67b23cc0df0f..f5dfdb9d80e9 100644 --- a/scripts/genksyms/genksyms.c +++ b/scripts/genksyms/genksyms.c @@ -680,7 +680,7 @@ void export_symbol(const char *name) if (flag_dump_defs) fputs(">\n", debugfile); - printf("__crc_%s = 0x%08lx;\n", name, crc); + printf("#SYMVER %s 0x%08lx\n", name, crc); } } From patchwork Wed May 11 16:45:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846472 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6F77C433F5 for ; Wed, 11 May 2022 16:49:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344983AbiEKQto (ORCPT ); Wed, 11 May 2022 12:49:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235083AbiEKQtm (ORCPT ); Wed, 11 May 2022 12:49:42 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC2B295DD9; Wed, 11 May 2022 09:49:40 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc2031975; Thu, 12 May 2022 01:47:39 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc2031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287660; bh=VYUdovbg04B1I3Qun6PzI9TK8mfwFQze5k3BA9jGnGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JsORAX5Qgso+eYGERjdufONMEUXA4EAsZn9cse4dvEb6eyIxshcJtLD4N03zxqnYa B49TU6NCNfAcv9/LgDXCilVYJV7JEUI0CtY/h32RjXG0gJqnOecDjOoYtddlyO8De2 iR4V0A6jxEQGmYrO4fzCfhdWj8x6jRNPFxS9Uq67FAYyoAklPq85nH9Vx7QxAIWlEK dxjj1n4qtRt59O7WgVuTZE9Wqf8+C9XE6LclY7iez9dLjuawvmVgss0ak6mkesfjxC YIzhJ+Y5xg4foyQ8WzrWTYJz7FvIowvAaL6m/SwIofwB1onMweAEI1V4il1fwRQgKC PG0h0xmGz0T+A== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 07/12] kbuild: do not create *.prelink.o for Clang LTO or IBT Date: Thu, 12 May 2022 01:45:09 +0900 Message-Id: <20220511164514.2741934-8-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: When CONFIG_LTO_CLANG=y, additional intermediate *.prelink.o is created for each module. Also, objtool is postponed until LLVM IR is converted to ELF. CONFIG_X86_KERNEL_IBT works in a similar way to postpone objtool until objects are merged together. This commit stops generating *.prelink.o, so the build flow will look similar with/without LTO. The following figures show how the LTO build currently works, and how this commit is changing it. Current build flow ================== [1] single-object module $(LD) $(CC) +objtool $(LD) foo.c --------------------> foo.o -----> foo.prelink.o -----> foo.ko (LLVM IR) (ELF) | | foo.mod.o --/ [2] multi-object module $(LD) $(CC) $(AR) +objtool $(LD) foo1.c -----> foo1.o -----> foo.o -----> foo.prelink.o -----> foo.ko | (archive) (ELF) | foo2.c -----> foo2.o --/ | (LLVM IR) foo.mod.o --/ One confusion is foo.o in multi-object module is an archive despite of its suffix. New build flow ============== [1] single-object module Since there is only one object, there is no need to keep the LLVM IR. Use $(CC)+$(LD) to generate an ELF object in one build rule. When LTO is disabled, $(LD) is unneeded because $(CC) produces an ELF object. $(CC)+$(LD)+objtool $(LD) foo.c ----------------------------> foo.o ---------> foo.ko (ELF) | | foo.mod.o --/ [2] multi-object module Previously, $(AR) was used to combine LLVM bitcode into an archive, but there was no technical reason to do so. Use $(LD) to merge them into a single ELF object. $(LD) $(CC) +objtool $(LD) foo1.c ---------> foo1.o ---------> foo.o ---------> foo.ko | (ELF) | foo2.c ---------> foo2.o ----/ | (LLVM IR) foo.mod.o --/ Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor Reviewed-by: Sami Tolvanen --- (no changes since v2) Changes in v2: - replace the chain of $(if ...) with $(and ) scripts/Kbuild.include | 4 +++ scripts/Makefile.build | 58 ++++++++++++--------------------------- scripts/Makefile.lib | 7 ----- scripts/Makefile.modfinal | 5 ++-- scripts/Makefile.modpost | 9 ++---- scripts/mod/modpost.c | 7 ----- 6 files changed, 25 insertions(+), 65 deletions(-) diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 3514c2149e9d..455a0a6ce12d 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -15,6 +15,10 @@ pound := \# # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o dot-target = $(dir $@).$(notdir $@) +### +# Name of target with a '.tmp_' as filename prefix. foo/bar.o => foo/.tmp_bar.o +tmp-target = $(dir $@).tmp_$(notdir $@) + ### # The temporary file to save gcc -MMD generated dependencies must not # contain a comma diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 461998a2ad2b..838ea5e83174 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -88,10 +88,6 @@ endif targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \ $(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) -ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) -targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m))) -endif - ifdef need-modorder targets-for-modules += $(obj)/modules.order endif @@ -152,8 +148,16 @@ $(obj)/%.ll: $(src)/%.c FORCE # The C file is compiled and updated dependency information is generated. # (See cmd_cc_o_c + relevant part of rule_cc_o_c) +is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) + +ifdef CONFIG_LTO_CLANG +cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) +endif + quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ - cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< $(cmd_objtool) + cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \ + $(cmd_ld_single_m) \ + $(cmd_objtool) ifdef CONFIG_MODVERSIONS # When module versioning is enabled the following steps are executed: @@ -224,21 +228,16 @@ cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(o endif # CONFIG_STACK_VALIDATION -ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) - -# Skip objtool for LLVM bitcode -$(obj)/%.o: objtool-enabled := - -else # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file -$(obj)/%.o: objtool-enabled = $(if $(filter-out y%, \ - $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) +is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) -endif +delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT)) + +$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) ifdef CONFIG_TRIM_UNUSED_KSYMS cmd_gen_ksymdeps = \ @@ -267,24 +266,6 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) -ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) -# Module .o files may contain LLVM bitcode, compile them into native code -# before ELF processing -quiet_cmd_cc_prelink_modules = LD [M] $@ - cmd_cc_prelink_modules = \ - $(LD) $(ld_flags) -r -o $@ \ - --whole-archive $(filter-out FORCE,$^) \ - $(cmd_objtool) - -# objtool was skipped for LLVM bitcode, run it now that we have compiled -# modules into native code -$(obj)/%.prelink.o: objtool-enabled = y -$(obj)/%.prelink.o: part-of-module := y - -$(obj)/%.prelink.o: $(obj)/%.o FORCE - $(call if_changed,cc_prelink_modules) -endif - cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ @@ -294,7 +275,7 @@ $(obj)/%.mod: FORCE # List module undefined symbols cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@ -$(obj)/%.usyms: $(obj)/%$(mod-prelink-ext).o FORCE +$(obj)/%.usyms: $(obj)/%.o FORCE $(call if_changed,undefined_syms) quiet_cmd_cc_lst_c = MKLST $@ @@ -416,16 +397,11 @@ $(obj)/modules.order: $(obj-m) FORCE $(obj)/lib.a: $(lib-y) FORCE $(call if_changed,ar) -ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) -quiet_cmd_link_multi-m = AR [M] $@ -cmd_link_multi-m = \ - rm -f $@; \ - $(AR) cDPrsT $@ @$(patsubst %.o,%.mod,$@) -else quiet_cmd_link_multi-m = LD [M] $@ - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) -endif + cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool) +$(multi-obj-m): objtool-enabled := $(delay-objtool) +$(multi-obj-m): part-of-module := y $(multi-obj-m): %.o: %.mod FORCE $(call if_changed,link_multi-m) $(call multi_depend, $(multi-obj-m), .o, -objs -y -m) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 0453a1904646..f75138385449 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -225,13 +225,6 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \ $(addprefix -I,$(DTC_INCLUDE)) \ -undef -D__DTS__ -ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),) -# With CONFIG_LTO_CLANG, .o files in modules might be LLVM bitcode, so we -# need to run LTO to compile them into native code (.lto.o) before further -# processing. -mod-prelink-ext := .prelink -endif - # Useful for describing the dependency of composite objects # Usage: # $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add) diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 7f39599e9fae..35100e981f4a 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -9,7 +9,7 @@ __modfinal: include include/config/auto.conf include $(srctree)/scripts/Kbuild.include -# for c_flags and mod-prelink-ext +# for c_flags include $(srctree)/scripts/Makefile.lib # find all modules listed in modules.order @@ -54,9 +54,8 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \ $(cmd); \ printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:) - # Re-generate module BTFs if either module's .ko or vmlinux changed -$(modules): %.ko: %$(mod-prelink-ext).o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE +$(modules): %.ko: %.o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE +$(call if_changed_except,ld_ko_o,vmlinux) ifdef CONFIG_DEBUG_INFO_BTF_MODULES +$(if $(newer-prereqs),$(call cmd,btf_ko)) diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 48585c4d04ad..f2ce411acd59 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -41,9 +41,6 @@ __modpost: include include/config/auto.conf include $(srctree)/scripts/Kbuild.include -# for mod-prelink-ext -include $(srctree)/scripts/Makefile.lib - MODPOST = scripts/mod/modpost \ $(if $(CONFIG_MODVERSIONS),-m) \ $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ @@ -118,8 +115,6 @@ $(input-symdump): @echo >&2 ' Modules may not have dependencies or modversions.' @echo >&2 ' You may get many unresolved symbol warnings.' -modules := $(sort $(shell cat $(MODORDER))) - # KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),) MODPOST += -w @@ -128,9 +123,9 @@ endif # Read out modules.order to pass in modpost. # Otherwise, allmodconfig would fail with "Argument list too long". quiet_cmd_modpost = MODPOST $@ - cmd_modpost = sed 's/\.ko$$/$(mod-prelink-ext)\.o/' $< | $(MODPOST) -T - + cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T - -$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(mod-prelink-ext).o) FORCE +$(output-symdump): $(MODORDER) $(input-symdump) FORCE $(call if_changed,modpost) targets += $(output-symdump) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 6b47a8723389..18f4d4a5a0ee 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -716,10 +716,6 @@ static char *remove_dot(char *s) size_t m = strspn(s + n + 1, "0123456789"); if (m && (s[n + m] == '.' || s[n + m] == 0)) s[n] = 0; - - /* strip trailing .prelink */ - if (strends(s, ".prelink")) - s[strlen(s) - 8] = '\0'; } return s; } @@ -839,9 +835,6 @@ static void read_symbols(const char *modname) /* strip trailing .o */ tmp = NOFAIL(strdup(modname)); tmp[strlen(tmp) - 2] = '\0'; - /* strip trailing .prelink */ - if (strends(tmp, ".prelink")) - tmp[strlen(tmp) - 8] = '\0'; mod = new_module(tmp); free(tmp); } From patchwork Wed May 11 16:45:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846478 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 152BFC46467 for ; Wed, 11 May 2022 16:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345045AbiEKQts (ORCPT ); Wed, 11 May 2022 12:49:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345030AbiEKQtq (ORCPT ); Wed, 11 May 2022 12:49:46 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27DC695DDE; Wed, 11 May 2022 09:49:41 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc3031975; Thu, 12 May 2022 01:47:40 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc3031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287661; bh=JATy8zCouz8u3lhW7zZYODfMQ0k0TkdVWlfxnhpO/F4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hYZAunszaDmkR8soaFwivCZyB2gcI024RUh21imB4CWfb+Bwmx9tNQsKAgM209tzg 7XAR5QNmNGgNjvjqAO9yEH6re6eojuiCM7gS95ilXpcaGZZLla3i3cJv/lwt0AedOx RD9/4GTHJJZZHkB2EXrX49SKZcLONqBMXpZ5Uoip4MiviB2VnYI8pRGOxgU38O8T81 1IvpXi9zryrV5qzpWLF5nNDX2Zn+bXRAjfw+GWax93rqp4qm0hBl1tOyp2herg3Yma P/iuI3Zg65TFJz6xr888OucWIL2PaFUUnGRXJr50UPEXoK14xZRJ2pnyU3Sm5cuNln xNUiQuRvcJkiA== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 08/12] kbuild: check static EXPORT_SYMBOL* by script instead of modpost Date: Thu, 12 May 2022 01:45:10 +0900 Message-Id: <20220511164514.2741934-9-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: The 'static' specifier and EXPORT_SYMBOL() are an odd combination. Commit 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions") tried to detect it, but this check has false negatives. Here is the sample code. Makefile: obj-y += foo1.o foo2.o foo1.c: #include static void foo(void) {} EXPORT_SYMBOL(foo); foo2.c: void foo(void) {} foo1.c exports the static symbol 'foo', but modpost cannot catch it because it is fooled by foo2.c, which has a global symbol with the same name. s->is_static is cleared if a global symbol with the same name is found somewhere, but EXPORT_SYMBOL() and the global symbol do not necessarily belong to the same compilation unit. This check should be done per compilation unit, but I do not know how to do it in modpost. modpost runs against vmlinux.o or modules, which merges multiple objects, then forgets their origin. It is true modpost gets access to the lists of all the member objects (.vmlinux.objs and *.mod), but modpost cannot parse individual objects because they may not be ELF but LLVM IR when CONFIG_LTO_CLANG=y. Add a simple bash script to parse the output from ${NM}. This works for CONFIG_LTO_CLANG=y because llvm-nm can dump symbols of LLVM IR files. Revert 15bfc2348d54. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- Changes in v5: - Add more comments in the script Changes in v4: - New patch scripts/Makefile.build | 4 +++ scripts/check-local-export | 64 ++++++++++++++++++++++++++++++++++++++ scripts/mod/modpost.c | 28 +---------------- 3 files changed, 69 insertions(+), 27 deletions(-) create mode 100755 scripts/check-local-export diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 838ea5e83174..c2a173b3fd60 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -244,9 +244,12 @@ cmd_gen_ksymdeps = \ $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd endif +cmd_check_local_export = $(srctree)/scripts/check-local-export $@ + define rule_cc_o_c $(call cmd_and_fixdep,cc_o_c) $(call cmd,gen_ksymdeps) + $(call cmd,check_local_export) $(call cmd,checksrc) $(call cmd,checkdoc) $(call cmd,gen_objtooldep) @@ -257,6 +260,7 @@ endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) $(call cmd,gen_ksymdeps) + $(call cmd,check_local_export) $(call cmd,gen_objtooldep) $(call cmd,gen_symversions_S) endef diff --git a/scripts/check-local-export b/scripts/check-local-export new file mode 100755 index 000000000000..829e0591c0be --- /dev/null +++ b/scripts/check-local-export @@ -0,0 +1,64 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-only +# +# Copyright (C) 2022 Masahiro Yamada +# +# Exit with error if a local exported symbol is found. +# EXPORT_SYMBOL should be used for global symbols. + +set -e + +declare -A symbol_types +declare -a export_symbols + +exit_code=0 + +while read value type name +do + # Exceptional case for Clang LTO. + # llvm-nm outputs this: + # "---------------- t" + # Skip this line because the name is empty. + if [[ ${value} = -* && -z ${name} ]]; then + continue + fi + + # For undefined symbols, the first field (value) is empty. + # The outout looks like this: + # " U _printk" + # Shift the fields. + if [[ -z ${name} ]]; then + name=${type} + type=${value} + fi + + # save (name, type) in the associative array + symbol_types[${name}]=${type} + + # append the exported symbol to the array + if [[ ${name} == __ksymtab_* ]]; then + export_symbols+=(${name#__ksymtab_}) + fi + + # If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) + # shows 'no symbols' diagnostic (but exits with 0). It is harmless and + # hidden by '2>/dev/null'. However, it suppresses real error messages + # as well. Add a hand-crafted error message here. + # + # Use -q instead of 2>/dev/null when we upgrade the minimum version of + # binutils to 2.37, llvm to 13.0.0. +done < <(${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; false; } ) + +# Catch error in the process substitution +wait $! + +for name in "${export_symbols[@]}" +do + # nm(3) says "If lowercase, the symbol is usually local" + if [[ ${symbol_types[$name]} =~ [a-z] ]]; then + echo "$@: error: local symbol '${name}' was exported" >&2 + exit_code=1 + fi +done + +exit ${exit_code} diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 18f4d4a5a0ee..50dbd2e9939c 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -212,7 +212,6 @@ struct symbol { unsigned int crc; bool crc_valid; bool weak; - bool is_static; /* true if symbol is not global */ bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */ char name[]; }; @@ -242,7 +241,7 @@ static struct symbol *alloc_symbol(const char *name) memset(s, 0, sizeof(*s)); strcpy(s->name, name); - s->is_static = true; + return s; } @@ -875,20 +874,6 @@ static void read_symbols(const char *modname) sym_get_data(&info, sym)); } - // check for static EXPORT_SYMBOL_* functions && global vars - for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { - unsigned char bind = ELF_ST_BIND(sym->st_info); - - if (bind == STB_GLOBAL || bind == STB_WEAK) { - struct symbol *s = - find_symbol(remove_dot(info.strtab + - sym->st_name)); - - if (s) - s->is_static = false; - } - } - check_sec_ref(mod, modname, &info); if (!mod->is_vmlinux) { @@ -1318,7 +1303,6 @@ static void read_dump(const char *fname) mod->from_dump = true; } s = sym_add_exported(symname, mod, gpl_only); - s->is_static = false; sym_set_crc(s, crc); sym_update_namespace(symname, namespace); } @@ -1383,7 +1367,6 @@ int main(int argc, char **argv) char *missing_namespace_deps = NULL; char *dump_write = NULL, *files_source = NULL; int opt; - int n; LIST_HEAD(dump_lists); struct dump_list *dl, *dl2; @@ -1459,15 +1442,6 @@ int main(int argc, char **argv) if (sec_mismatch_count && !sec_mismatch_warn_only) error("Section mismatches detected.\n" "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); - for (n = 0; n < SYMBOL_HASH_SIZE; n++) { - struct symbol *s; - - for (s = symbolhash[n]; s; s = s->next) { - if (s->is_static) - error("\"%s\" [%s] is a static EXPORT_SYMBOL\n", - s->name, s->module->name); - } - } if (nr_unresolved > MAX_UNRESOLVED_REPORTS) warn("suppressed %u unresolved symbol warnings because there were too many)\n", From patchwork Wed May 11 16:45:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846475 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 615D8C388F3 for ; Wed, 11 May 2022 16:49:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345043AbiEKQtr (ORCPT ); Wed, 11 May 2022 12:49:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345026AbiEKQtq (ORCPT ); Wed, 11 May 2022 12:49:46 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A06195DD9; Wed, 11 May 2022 09:49:41 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc4031975; Thu, 12 May 2022 01:47:41 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc4031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287662; bh=tcr+72ZYpbdDhhd7b5O3qNkSWb92WQKtLNqtDxevyAs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1xN57X9s6ScLJ/Z2hb1pNWWGLy1nt5xrcw/SRTDzpwMQbvnE8A08WHb1tRL2DBKCO +pXkDzpxbY81fwxbG0a4ZZkdXAogExaeNGygVj8OuLcQNuJ7AiRunzbNiBtIc7spg1 8+kVanlYtmiRWoi0IcsTtPqIxwux0W9L6x/FwUyQ60BvJ379AzCT3xh3/e9TxPIp5S Pc8nBrjlOMjG0duMJdm6spy738mTTr+f+FFcKcDaOyjaayqqqYRWWVZ0bHOrh9LfyX sMYGko/4vxzWoqMu0AiEUGkSvhzF7286ufk7BC0AMXMVPovVKTcm1HkwUoJrVQMncw 9gXlUynDCRMKg== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 09/12] kbuild: make built-in.a rule robust against too long argument error Date: Thu, 12 May 2022 01:45:11 +0900 Message-Id: <20220511164514.2741934-10-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: Kbuild runs at the top of objtree instead of changing the working directory to subdirectories. I think this design is nice overall but some commands have a scalability issue. The build command of built-in.a is one of them whose length scales with: O(D * N) Here, D is the length of the directory path (i.e. $(obj)/ prefix), N is the number of objects in the Makefile, O() is the big O notation. The deeper directory the Makefile directory is located, the more easily it will hit the too long argument error. We can make it better. Trim the $(obj)/ by Make's builtin function, and restore it by a shell command (sed). With this, the command length scales with: O(D + N) In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as builtin (CONFIG_DRM_I915=y) and compare drivers/gpu/drm/i915/.built-in.a.cmd with/without this commit. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor --- (no changes since v2) Changes in v2: - New patch scripts/Makefile.build | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index c2a173b3fd60..8f1a355df7aa 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -374,7 +374,10 @@ $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; # quiet_cmd_ar_builtin = AR $@ - cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) + cmd_ar_builtin = rm -f $@; \ + echo $(patsubst $(obj)/%,%,$(real-prereqs)) | \ + sed -E 's:([^ ]+):$(obj)/\1:g' | \ + xargs $(AR) cDPrST $@ $(obj)/built-in.a: $(real-obj-y) FORCE $(call if_changed,ar_builtin) From patchwork Wed May 11 16:45:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846473 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67014C43219 for ; Wed, 11 May 2022 16:49:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345018AbiEKQtp (ORCPT ); Wed, 11 May 2022 12:49:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233496AbiEKQtm (ORCPT ); Wed, 11 May 2022 12:49:42 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AAF9A93982; Wed, 11 May 2022 09:49:40 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc5031975; Thu, 12 May 2022 01:47:42 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc5031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287663; bh=OcOEuS6jEbLubdZRYm9mI6nzM08ugGxo0tuefY4hIgE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jXi1gJPHIE2xagfeR2MNcfLTDFlg9D5O9cnkBMlaoyva8Do8oJfp6T+S9S4xs+LXI mbrFTqdzrHF0wP0OVeZc1gHvb856yx+ZfDsW6UnXoSwnaZLi6xTmLkkNem16UBBP7G Mv9n97/BoZmFifFt7YxrYZJQzzWpLiqvfELN1kUyI23LFUQWDtOBBq+cP+7B+29kaS heJui4xv66QP7cK5llyJUm9hDLvTD/WnVJAdHb5C1xVoNZfo0IQHttkWQBZvPgU0k4 LhNu07C+jWfwR7Z1xyAiP00Tzt2EkDe7UTV97+1Ytkg7hTmnpbuDpNBg7j27PDMu7c tiqDnu6ifEqMQ== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada Subject: [PATCH v5 10/12] kbuild: make *.mod rule robust against too long argument error Date: Thu, 12 May 2022 01:45:12 +0900 Message-Id: <20220511164514.2741934-11-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: Like built-in.a, the command length of the *.mod rule scales with the depth of the directory times the number of objects in the Makefile. Add $(obj)/ by the shell command (awk) instead of by Make's builtin function. In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as a module (CONFIG_DRM_I915=m) and compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. The issue is more critical for external modules because the M= path can be very long as Jeff Johnson reported before [1]. [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/ Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor --- (no changes since v2) Changes in v2: - New patch scripts/Makefile.build | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 8f1a355df7aa..f546b5f1f33f 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -270,8 +270,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) -cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ - $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ +cmd_mod = echo $(call real-search, $*.o, .o, -objs -y -m) | \ + $(AWK) -v RS='( |\n)' '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ $(obj)/%.mod: FORCE $(call if_changed,mod) From patchwork Wed May 11 16:45:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846474 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB065C433EF for ; Wed, 11 May 2022 16:49:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345035AbiEKQtr (ORCPT ); Wed, 11 May 2022 12:49:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235800AbiEKQtq (ORCPT ); Wed, 11 May 2022 12:49:46 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A36F95DDB; Wed, 11 May 2022 09:49:41 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc6031975; Thu, 12 May 2022 01:47:43 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc6031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287664; bh=PfsqhsCBk5DMJKQrgxjPrt4cR290nXSjW4ewrtsP89A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KGPJJDyaNocbo6ncNt90Q/OY7ihHW9tXr3BUWHXD4rjMD3KkrdCuYQZTTVomseqSK +XTfWkakm1H4RwK0EbAITtDKkiiAWjT8O/6BZqBXHN/rVs4Q1szUu/FPRyrbwrrzV0 eh/ATsHp2W7mHqysKrYp5SE61AiXtfsPnEra23WGRjfzpMzlwUP6MYeY1NoYNI4utk pZV5zT4e++CpCbsBFhvg07OMQ1FdS0zgT72+Ne+un4xKMRHYZBz2fyEsurC8zCVL1j 4THxnWfD6Pa3WElSRT+CekpOBnMwVZMMCbvzWIiwwQJLolqwlbnXUralfrpajp7JYT YrzXYa2EGODug== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada , Kees Cook Subject: [PATCH v5 11/12] kbuild: add cmd_and_savecmd macro Date: Thu, 12 May 2022 01:45:13 +0900 Message-Id: <20220511164514.2741934-12-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: Separate out the command execution part of if_changed, as we did for if_changed_dep. This allows us to reuse it in if_changed_rule. define rule_foo $(call cmd_and_savecmd,foo) $(call cmd,bar) endef Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Reviewed-by: Nicolas Schier --- (no changes since v4) Changes in v4: - New. Resent of my previous submission. https://lore.kernel.org/all/20210831074004.3195284-10-masahiroy@kernel.org/ scripts/Kbuild.include | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 455a0a6ce12d..ece44b735061 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -142,9 +142,11 @@ check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing) if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE) # Execute command if command has changed or prerequisite(s) are updated. -if_changed = $(if $(if-changed-cond), \ +if_changed = $(if $(if-changed-cond),$(cmd_and_savecmd),@:) + +cmd_and_savecmd = \ $(cmd); \ - printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:) + printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd # Execute the command and also postprocess generated .d dependencies file. if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:) From patchwork Wed May 11 16:45:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 12846482 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C844C433F5 for ; Wed, 11 May 2022 16:51:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231909AbiEKQvR (ORCPT ); Wed, 11 May 2022 12:51:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345101AbiEKQuh (ORCPT ); Wed, 11 May 2022 12:50:37 -0400 Received: from conuserg-08.nifty.com (conuserg-08.nifty.com [210.131.2.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FB56980B0; Wed, 11 May 2022 09:50:04 -0700 (PDT) Received: from grover.jp (133-32-177-133.west.xps.vectant.ne.jp [133.32.177.133]) (authenticated) by conuserg-08.nifty.com with ESMTP id 24BGlWc7031975; Thu, 12 May 2022 01:47:44 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-08.nifty.com 24BGlWc7031975 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1652287665; bh=lwhcZwty1WSqzMwcqIa4FpY71JgLgetW2nQZRkklH+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vbl4SEiYvvF37f1IoBEjasxAsVDVSQV8iEM8Mi1h0FEwr6nbrD3P3UYOZTcXB+dwW P4z9VJ4VCWJvC1cJ1pmve8jsN9WLx+eVX79Xl6TrT24LXAougV9Awt53/UrOSkZd43 X5EErlnVqv3GL29CA/j+CRK/e3buKnMpnmqT6knIllg7DKJ7KcmM/wga5P7pkHiye6 7Ntd8KWojBuvIyoY6awGSQNZfD7l35B6l5NF8xgdOhRDKMrTfKY1D5UlWG6fqVCJ0C yVqCAChqiTv/BoII/V6PNLSr8f0DT6kA6jxx/hAq260ykEre9DLp5hGZYDAkUG3GK/ a6HnJhQ6XrVqA== X-Nifty-SrcIP: [133.32.177.133] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Peter Zijlstra , linux-modules@vger.kernel.org, llvm@lists.linux.dev, Ard Biesheuvel , Sami Tolvanen , Masahiro Yamada , Kees Cook , Josh Poimboeuf Subject: [PATCH v5 12/12] kbuild: rebuild multi-object modules when objtool is updated Date: Thu, 12 May 2022 01:45:14 +0900 Message-Id: <20220511164514.2741934-13-masahiroy@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220511164514.2741934-1-masahiroy@kernel.org> References: <20220511164514.2741934-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: When CONFIG_LTO_CLANG or CONFIG_X86_KERNEL_IBT is enabled, objtool for multi-object modules is postponed until the objects are linked together. Make sure to re-run objtool and re-link multi-object modules when objtool is updated. Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Acked-by: Josh Poimboeuf Reviewed-by: Nicolas Schier --- (no changes since v4) Changes in v4: - New Resent of my previous submission https://lore.kernel.org/linux-kbuild/20210831074004.3195284-11-masahiroy@kernel.org/ scripts/Makefile.build | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index f546b5f1f33f..4e6902e099e8 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -404,13 +404,18 @@ $(obj)/modules.order: $(obj-m) FORCE $(obj)/lib.a: $(lib-y) FORCE $(call if_changed,ar) -quiet_cmd_link_multi-m = LD [M] $@ - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool) +quiet_cmd_ld_multi_m = LD [M] $@ + cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool) + +define rule_ld_multi_m + $(call cmd_and_savecmd,ld_multi_m) + $(call cmd,gen_objtooldep) +endef $(multi-obj-m): objtool-enabled := $(delay-objtool) $(multi-obj-m): part-of-module := y $(multi-obj-m): %.o: %.mod FORCE - $(call if_changed,link_multi-m) + $(call if_changed_rule,ld_multi_m) $(call multi_depend, $(multi-obj-m), .o, -objs -y -m) targets := $(filter-out $(PHONY), $(targets))