[2/3] x86/boot: Add $(CLANG_FLAGS) to compressed KBUILD_CFLAGS
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Message ID 20210326000435.4785-3-nathan@kernel.org
State Accepted
Commit d5cbd80e302dfea59726c44c56ab7957f822409f
Headers show
  • Fix cross compiling x86 with clang
Related show

Commit Message

Nathan Chancellor March 26, 2021, 12:04 a.m. UTC
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>
 arch/x86/boot/compressed/Makefile | 1 +
 1 file changed, 1 insertion(+)

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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
 # sev-es.c indirectly inludes inat-table.h which is generated during
 # compilation and stored in $(objtree). Add the directory to the includes so