From: Masahiro Yamada <masahiroy@xxxxxxxxxx>
commit feb843a469fb0ab00d2d23cfb9bcc379791011bb upstream.
When preprocessing arch/*/kernel/vmlinux.lds.S, the target triple is
not passed to $(CPP) because we add it only to KBUILD_{C,A}FLAGS.
As a result, the linker script is preprocessed with predefined macros
for the build host instead of the target.
Assuming you use an x86 build machine, compare the following:
$ clang -dM -E -x c /dev/null
$ clang -dM -E -x c /dev/null -target aarch64-linux-gnu
There is no actual problem presumably because our linker scripts do not
rely on such predefined macros, but it is better to define correct ones.
Move $(CLANG_FLAGS) to KBUILD_CPPFLAGS, so that all *.c, *.S, *.lds.S
will be processed with the proper target triple.
[Note]
After the patch submission, we got an actual problem that needs this
commit. (CBL issue 1859)
Link: https://github.com/ClangBuiltLinux/linux/issues/1859
Reported-by: Tom Rini <trini@xxxxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
scripts/Makefile.clang | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/scripts/Makefile.clang
+++ b/scripts/Makefile.clang
@@ -34,6 +34,5 @@ CLANG_FLAGS += -Werror=unknown-warning-o
CLANG_FLAGS += -Werror=ignored-optimization-argument
CLANG_FLAGS += -Werror=option-ignored
CLANG_FLAGS += -Werror=unused-command-line-argument
-KBUILD_CFLAGS += $(CLANG_FLAGS)
-KBUILD_AFLAGS += $(CLANG_FLAGS)
+KBUILD_CPPFLAGS += $(CLANG_FLAGS)
export CLANG_FLAGS
