From: Vasily Gorbik <gor@xxxxxxxxxxxxx> [ Upstream commit 253b3c4b2920e07ce9e2b18800b9b65245e2fafa ] clang 10 introduces -mpacked-stack compiler option implementation. At the same time currently it does not support a combination of -mpacked-stack and -mbackchain. This leads to the following build error: clang: error: unsupported option '-mpacked-stack with -mbackchain' for target 's390x-ibm-linux' If/when clang adds support for a combination of -mpacked-stack and -mbackchain it would also require -msoft-float (like gcc does). According to Ulrich Weigand "stack slot assigned to the kernel backchain overlaps the stack slot assigned to the FPR varargs (both are required to be placed immediately after the saved r15 slot if present)." Extend -mpacked-stack compiler option support check to include all 3 options -mpacked-stack -mbackchain -msoft-float which must present to support -mpacked-stack with -mbackchain. Acked-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/s390/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/Makefile b/arch/s390/Makefile index e6c2e8925fefa..4bccde36cb161 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -63,7 +63,7 @@ cflags-y += -Wa,-I$(srctree)/arch/$(ARCH)/include # cflags-$(CONFIG_FRAME_POINTER) += -fno-optimize-sibling-calls -ifeq ($(call cc-option-yn,-mpacked-stack),y) +ifeq ($(call cc-option-yn,-mpacked-stack -mbackchain -msoft-float),y) cflags-$(CONFIG_PACK_STACK) += -mpacked-stack -D__PACK_STACK aflags-$(CONFIG_PACK_STACK) += -D__PACK_STACK endif -- 2.20.1
