arm64: lse: remove -fcall-used-x0 flag

x0 is not callee-saved in the PCS. So there is no need to specify
-fcall-used-x0.

Clang doesn't currently support -fcall-used flags. This patch will help
building the kernel with clang.

Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Tri Vo <trong@android.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
index f28f91f..69ff988 100644 (file)
--- a/arch/arm64/lib/Makefile
+++ b/arch/arm64/lib/Makefile
@@ -12,7 +12,7 @@ lib-y         := clear_user.o delay.o copy_from_user.o                \
 # when supported by the CPU. Result and argument registers are handled
 # correctly, based on the function prototype.
 lib-$(CONFIG_ARM64_LSE_ATOMICS) += atomic_ll_sc.o
-CFLAGS_atomic_ll_sc.o  := -fcall-used-x0 -ffixed-x1 -ffixed-x2         \
+CFLAGS_atomic_ll_sc.o  := -ffixed-x1 -ffixed-x2                        \
                   -ffixed-x3 -ffixed-x4 -ffixed-x5 -ffixed-x6          \
                   -ffixed-x7 -fcall-saved-x8 -fcall-saved-x9           \
                   -fcall-saved-x10 -fcall-saved-x11 -fcall-saved-x12   \