[PATCH] kbuild: add $(CLANG_CFLAGS) to KBUILD_CPPFLAGS

From: Masahiro Yamada
Date: Sun Apr 09 2023 - 10:54:11 EST


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 $(CFLAGS_CFLAGS) to KBUILD_CPPFLAGS, so that all *.c, *.S, *.lds.S
will be processed with the proper target triple.

Reported-by: Tom Rini <trini@xxxxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

scripts/Makefile.clang | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang
index 70b354fa1cb4..93ca059cc3b8 100644
--- a/scripts/Makefile.clang
+++ b/scripts/Makefile.clang
@@ -38,6 +38,5 @@ CLANG_FLAGS += -Werror=unknown-warning-option
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
--
2.37.2