From: Nathan Chancellor nathan@kernel.org
[ Upstream commit d5cbd80e302dfea59726c44c56ab7957f822409f ]
When cross compiling x86 on an ARM machine with clang, there are several errors along the lines of:
arch/x86/include/asm/string_64.h:27:10: error: invalid output constraint '=&c' in asm
This happens because the compressed boot Makefile reassigns KBUILD_CFLAGS and drops the clang flags that set the target architecture ('--target=') and the path to the GNU cross tools ('--prefix='), meaning that the host architecture is targeted.
These flags are available as $(CLANG_FLAGS) from the main Makefile so add them to the compressed boot folder's KBUILD_CFLAGS 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/20210326000435.4785-3-nathan@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/boot/compressed/Makefile | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index e0bc3988c3fa..6e5522aebbbd 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -46,6 +46,7 @@ KBUILD_CFLAGS += -D__DISABLE_EXPORTS # Disable relocation relaxation in case the link is not PIE. KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no) KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h +KBUILD_CFLAGS += $(CLANG_FLAGS)
# sev-es.c indirectly inludes inat-table.h which is generated during # compilation and stored in $(objtree). Add the directory to the includes so