From 2bc92c61c5417982e7b92ba628281f411d31013c Mon Sep 17 00:00:00 2001 From: Jack Brennen Date: Tue, 26 Sep 2023 08:40:44 -0400 Subject: modpost: Optimize symbol search from linear to binary search [ Upstream commit 4074532758c5c367d3fcb8d124150824a254659d ] Modify modpost to use binary search for converting addresses back into symbol references. Previously it used linear search. This change saves a few seconds of wall time for defconfig builds, but can save several minutes on allyesconfigs. Before: $ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error" $ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o 198.38user 1.27system 3:19.71elapsed After: $ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error" $ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o 11.91user 0.85system 0:12.78elapsed Signed-off-by: Jack Brennen Tested-by: Nick Desaulniers Signed-off-by: Masahiro Yamada Stable-dep-of: 1102f9f85bf6 ("modpost: do not make find_tosym() return NULL") Signed-off-by: Sasha Levin --- scripts/mod/modpost.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'scripts/mod/modpost.h') diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 5f94c2c9f2d9..6413f26fcb6b 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -10,6 +10,7 @@ #include #include #include +#include "../../include/linux/module_symbol.h" #include "list.h" #include "elfconfig.h" @@ -128,6 +129,8 @@ struct elf_info { * take shndx from symtab_shndx_start[N] instead */ Elf32_Word *symtab_shndx_start; Elf32_Word *symtab_shndx_stop; + + struct symsearch *symsearch; }; /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ @@ -154,6 +157,28 @@ static inline unsigned int get_secindex(const struct elf_info *info, return index; } +/* + * If there's no name there, ignore it; likewise, ignore it if it's + * one of the magic symbols emitted used by current tools. + * + * Internal symbols created by tools should be ignored by modpost. + */ +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_mapping_symbol(name); +} + +/* symsearch.c */ +void symsearch_init(struct elf_info *elf); +void symsearch_finish(struct elf_info *elf); +Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance); + /* file2alias.c */ void handle_moddevtable(struct module *mod, struct elf_info *info, Elf_Sym *sym, const char *symname); -- cgit v1.2.3