From: Nathan Chancellor nathan@kernel.org
[ Upstream commit 58d746c119dfa28e72fc35aacaf3d2a3ac625cd0 ]
When cross compiling x86 on an ARM machine with clang, there are several errors along the lines of:
arch/x86/include/asm/page_64.h:52:7: error: invalid output constraint '=D' in asm
This happens because the x86 flags in the EFI stub are not derived from KBUILD_CFLAGS like the other architectures are and the clang flags that set the target architecture ('--target=') and the path to the GNU cross tools ('--prefix=') are not present, meaning that the host architecture is targeted.
These flags are available as $(CLANG_FLAGS) from the main Makefile so add them to the cflags for x86 so that cross compiling works as expected.
Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Acked-by: Ard Biesheuvel ardb@kernel.org Link: https://lkml.kernel.org/r/20210326000435.4785-4-nathan@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/efi/libstub/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index c23466e05e60..d0537573501e 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -13,7 +13,8 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \ -Wno-pointer-sign \ $(call cc-disable-warning, address-of-packed-member) \ $(call cc-disable-warning, gnu) \ - -fno-asynchronous-unwind-tables + -fno-asynchronous-unwind-tables \ + $(CLANG_FLAGS)
# arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly # disable the stackleak plugin