From fbe078d397b4d59232f05fde977d3b1e7d0c2028 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Fri, 11 Dec 2020 10:46:23 -0800 Subject: kbuild: lto: add a default list of used symbols With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a binary when the .mod files are generated, which means they don't yet contain references to certain symbols that will be present in the final binaries. This includes intrinsic functions, such as memcpy, memmove, and memset [1], and stack protector symbols [2]. This change adds a default symbol list to use with CONFIG_TRIM_UNUSED_KSYMS when Clang's LTO is used. [1] https://llvm.org/docs/LangRef.html#standard-c-c-library-intrinsics [2] https://llvm.org/docs/LangRef.html#llvm-stackprotector-intrinsic Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20201211184633.3213045-7-samitolvanen@google.com --- init/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index b77c60f8b963..5271138b8742 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2297,6 +2297,7 @@ config TRIM_UNUSED_KSYMS config UNUSED_KSYMS_WHITELIST string "Whitelist of symbols to keep in ksymtab" depends on TRIM_UNUSED_KSYMS + default "scripts/lto-used-symbollist.txt" if LTO_CLANG help By default, all unused exported symbols will be un-exported from the build when TRIM_UNUSED_KSYMS is selected. -- cgit v1.2.3-70-g09d2