From: Masahiro Yamada masahiroy@kernel.org
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 $(CLANG_FLAGS) to KBUILD_CPPFLAGS, so that all *.c, *.S, *.lds.S will be processed with the proper target triple.
[Note] After the patch submission, we got an actual problem that needs this commit. (CBL issue 1859)
Link: https://github.com/ClangBuiltLinux/linux/issues/1859 Reported-by: Tom Rini trini@konsulko.com Signed-off-by: Masahiro Yamada masahiroy@kernel.org Reviewed-by: Nathan Chancellor nathan@kernel.org Tested-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Nathan Chancellor nathan@kernel.org --- Makefile | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/Makefile b/Makefile index f65e282f4a3f..16a23aaaa547 100644 --- a/Makefile +++ b/Makefile @@ -568,8 +568,7 @@ ifneq ($(LLVM_IAS),1) CLANG_FLAGS += -no-integrated-as endif CLANG_FLAGS += -Werror=unknown-warning-option -KBUILD_CFLAGS += $(CLANG_FLAGS) -KBUILD_AFLAGS += $(CLANG_FLAGS) +KBUILD_CPPFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS endif