From: Tor Vic torvic9@mailbox.org
commit 2398ce80152aae33b9501ef54452e09e8e8d4262 upstream.
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 torvic9@mailbox.org Reviewed-by: Nathan Chancellor nathan@kernel.org Tested-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/f2c018ee-5999-741e-58d4-e482d5246067@mailbox.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -192,8 +192,9 @@ 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