From: Masahiro Yamada <masahiroy@kernel.org> To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>, linux-arm-kernel@lists.infradead.org, Russell King <linux@armlinux.org.uk>, Masahiro Yamada <masahiroy@kernel.org>, Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Nicolas Schier <nicolas@fjasle.eu> Subject: [PATCH 4/7] modpost: refactor find_fromsym() and find_tosym() Date: Thu, 1 Jun 2023 21:09:58 +0900 [thread overview] Message-ID: <20230601121001.1071533-5-masahiroy@kernel.org> (raw) In-Reply-To: <20230601121001.1071533-1-masahiroy@kernel.org> find_fromsym() and find_tosym() are similar - both of them iterate in the .symtab section and return the nearest symbol. The difference between them is that find_tosym() allows a negative distance, but the distance must be less than 20. Factor out the common part into find_nearest_sym(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/mod/modpost.c | 95 ++++++++++++++++--------------------------- 1 file changed, 36 insertions(+), 59 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 5a5e802b160c..32d56efe3f3b 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1075,81 +1075,58 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) return !is_mapping_symbol(name); } -/** - * Find symbol based on relocation record info. - * In some cases the symbol supplied is a valid symbol so - * return refsym. If is_valid_name() == true, 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_tosym(struct elf_info *elf, Elf64_Sword addr, - Elf_Sym *relsym) +/* Look up the nearest symbol based on the section and the address */ +static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance) { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf64_Sword distance = 20; - Elf64_Sword d; - unsigned int relsym_secindex; - - if (is_valid_name(elf, relsym)) - return relsym; - - /* - * Strive to find a better symbol name, but the resulting name may not - * match the symbol referenced in the original code. - */ - 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_fromsym(struct elf_info *elf, Elf_Addr addr, - unsigned int secndx) -{ - Elf_Sym *sym; - Elf_Sym *near = NULL; - Elf_Addr distance = ~0; + Elf_Addr distance; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; - if (sym->st_value <= addr && addr - sym->st_value <= distance) { + + if (addr >= sym->st_value) distance = addr - sym->st_value; + else if (allow_negative) + distance = sym->st_value - addr; + else + continue; + + if (distance <= min_distance) { + min_distance = distance; near = sym; } + + if (min_distance == 0) + break; } return near; } +static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx) +{ + return find_nearest_sym(elf, addr, secndx, false, ~0); +} + +static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) +{ + /* If the supplied symbol has a valid name, return it */ + if (is_valid_name(elf, sym)) + return sym; + + /* + * Strive to find a better symbol name, but the resulting name may not + * match the symbol referenced in the original code. + */ + return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20); +} + static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { if (secndx > elf->num_sections) -- 2.39.2
WARNING: multiple messages have this Message-ID (diff)
From: Masahiro Yamada <masahiroy@kernel.org> To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>, linux-arm-kernel@lists.infradead.org, Russell King <linux@armlinux.org.uk>, Masahiro Yamada <masahiroy@kernel.org>, Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Nicolas Schier <nicolas@fjasle.eu> Subject: [PATCH 4/7] modpost: refactor find_fromsym() and find_tosym() Date: Thu, 1 Jun 2023 21:09:58 +0900 [thread overview] Message-ID: <20230601121001.1071533-5-masahiroy@kernel.org> (raw) In-Reply-To: <20230601121001.1071533-1-masahiroy@kernel.org> find_fromsym() and find_tosym() are similar - both of them iterate in the .symtab section and return the nearest symbol. The difference between them is that find_tosym() allows a negative distance, but the distance must be less than 20. Factor out the common part into find_nearest_sym(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/mod/modpost.c | 95 ++++++++++++++++--------------------------- 1 file changed, 36 insertions(+), 59 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 5a5e802b160c..32d56efe3f3b 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1075,81 +1075,58 @@ static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) return !is_mapping_symbol(name); } -/** - * Find symbol based on relocation record info. - * In some cases the symbol supplied is a valid symbol so - * return refsym. If is_valid_name() == true, 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_tosym(struct elf_info *elf, Elf64_Sword addr, - Elf_Sym *relsym) +/* Look up the nearest symbol based on the section and the address */ +static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance) { Elf_Sym *sym; Elf_Sym *near = NULL; - Elf64_Sword distance = 20; - Elf64_Sword d; - unsigned int relsym_secindex; - - if (is_valid_name(elf, relsym)) - return relsym; - - /* - * Strive to find a better symbol name, but the resulting name may not - * match the symbol referenced in the original code. - */ - 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_fromsym(struct elf_info *elf, Elf_Addr addr, - unsigned int secndx) -{ - Elf_Sym *sym; - Elf_Sym *near = NULL; - Elf_Addr distance = ~0; + Elf_Addr distance; for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { if (get_secindex(elf, sym) != secndx) continue; if (!is_valid_name(elf, sym)) continue; - if (sym->st_value <= addr && addr - sym->st_value <= distance) { + + if (addr >= sym->st_value) distance = addr - sym->st_value; + else if (allow_negative) + distance = sym->st_value - addr; + else + continue; + + if (distance <= min_distance) { + min_distance = distance; near = sym; } + + if (min_distance == 0) + break; } return near; } +static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx) +{ + return find_nearest_sym(elf, addr, secndx, false, ~0); +} + +static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) +{ + /* If the supplied symbol has a valid name, return it */ + if (is_valid_name(elf, sym)) + return sym; + + /* + * Strive to find a better symbol name, but the resulting name may not + * match the symbol referenced in the original code. + */ + return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20); +} + static bool is_executable_section(struct elf_info *elf, unsigned int secndx) { if (secndx > elf->num_sections) -- 2.39.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-06-01 12:11 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-06-01 12:09 [PATCH 0/7] modpost: fix section mismatch detection for ARM Masahiro Yamada 2023-06-01 12:09 ` Masahiro Yamada 2023-06-01 12:09 ` [PATCH 1/7] modpost: fix section mismatch message for R_ARM_ABS32 Masahiro Yamada 2023-06-01 12:09 ` Masahiro Yamada 2023-06-01 12:09 ` [PATCH 2/7] modpost: fix section mismatch message for R_ARM_{PC24,CALL,JUMP24} Masahiro Yamada 2023-06-01 12:09 ` Masahiro Yamada 2023-06-01 12:09 ` [PATCH 3/7] modpost: detect section mismatch for R_ARM_{MOVW_ABS_NC,MOVT_ABS} Masahiro Yamada 2023-06-01 12:09 ` Masahiro Yamada 2023-06-01 12:09 ` Masahiro Yamada [this message] 2023-06-01 12:09 ` [PATCH 4/7] modpost: refactor find_fromsym() and find_tosym() Masahiro Yamada 2023-06-01 12:09 ` [PATCH 5/7] modpost: detect section mismatch for R_ARM_THM_{MOVW_ABS_NC,MOVT_ABS} Masahiro Yamada 2023-06-01 12:09 ` Masahiro Yamada 2023-06-01 12:23 ` Ard Biesheuvel 2023-06-01 12:23 ` Ard Biesheuvel 2023-06-01 14:28 ` Masahiro Yamada 2023-06-01 14:28 ` Masahiro Yamada 2023-06-01 12:10 ` [PATCH 6/7] modpost: fix section_mismatch message for R_ARM_THM_{CALL,JUMP24,JUMP19} Masahiro Yamada 2023-06-01 12:10 ` Masahiro Yamada 2023-06-01 12:10 ` [PATCH 7/7] modpost: detect section mismatch for R_ARM_REL32 Masahiro Yamada 2023-06-01 12:10 ` Masahiro Yamada 2023-06-01 12:40 ` Ard Biesheuvel 2023-06-01 12:40 ` Ard Biesheuvel 2023-06-01 14:35 ` Masahiro Yamada 2023-06-01 14:35 ` Masahiro Yamada 2023-06-01 14:40 ` Ard Biesheuvel 2023-06-01 14:40 ` Ard Biesheuvel
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20230601121001.1071533-5-masahiroy@kernel.org \ --to=masahiroy@kernel.org \ --cc=ardb@kernel.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kbuild@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux@armlinux.org.uk \ --cc=nathan@kernel.org \ --cc=ndesaulniers@google.com \ --cc=nicolas@fjasle.eu \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.