From: Nathan Chancellor natechancellor@gmail.com
[ Upstream commit 72cf3b3df423c1bbd8fa1056fed009d3a260f8a9 ]
Clang does not support this option and errors out:
clang-11: error: unknown argument: '-mexplicit-relocs'
Clang does not appear to need this flag like GCC does because the jalr check that was added in commit 976c23af3ee5 ("mips: vdso: add build time check that no 'jalr t9' calls left") passes just fine with
$ make ARCH=mips CC=clang CROSS_COMPILE=mipsel-linux-gnu- malta_defconfig arch/mips/vdso/
even before commit d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code").
-mrelax-pic-calls has been supported since clang 9, which is the earliest version that could build a working MIPS kernel, and it is the default for clang so just leave it be.
Fixes: d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code") Link: https://github.com/ClangBuiltLinux/linux/issues/890 Signed-off-by: Nathan Chancellor natechancellor@gmail.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Tested-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Paul Burton paulburton@kernel.org Cc: Ralf Baechle ralf@linux-mips.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/mips/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 08c835d48520b..3dcfdee678fb9 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -29,7 +29,7 @@ endif cflags-vdso := $(ccflags-vdso) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ -O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \ - -mrelax-pic-calls -mexplicit-relocs \ + -mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \ -fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \ $(call cc-option, -fno-asynchronous-unwind-tables) \ $(call cc-option, -fno-stack-protector)