From: Tor Vic Date: Thu, 10 Jun 2021 20:58:06 +0000 (+0000) Subject: x86, lto: Pass -stack-alignment only on LLD < 13.0.0 X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2398ce80152a;p=linux.git x86, lto: Pass -stack-alignment only on LLD < 13.0.0 Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1], leading to the following error message when building a LTO kernel with Clang-13 and LLD-13: ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument '-stack-alignment=8'. Try 'ld.lld --help' ld.lld: Did you mean '--stackrealign=8'? It also appears that the '-code-model' flag is not necessary anymore starting with LLVM-9 [2]. Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0. These flags were necessary because these flags were not encoded in the IR properly, so the link would restart optimizations without them. Now there are properly encoded in the IR, and these flags exposing implementation details are no longer necessary. [1] https://reviews.llvm.org/D103048 [2] https://reviews.llvm.org/D52322 Cc: stable@vger.kernel.org Link: https://github.com/ClangBuiltLinux/linux/issues/1377 Signed-off-by: Tor Vic Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/f2c018ee-5999-741e-58d4-e482d5246067@mailbox.org --- diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 307529417021a..cb5e8d39cac15 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -200,8 +200,9 @@ endif KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) ifdef CONFIG_LTO_CLANG -KBUILD_LDFLAGS += -plugin-opt=-code-model=kernel \ - -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) +ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0) +KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) +endif endif ifdef CONFIG_X86_NEED_RELOCS