kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS

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>
This commit is contained in:
Masahiro Yamada 2023-04-09 23:53:57 +09:00
parent cff6e7f50b
commit feb843a469
1 changed files with 1 additions and 2 deletions

View File

@ -34,6 +34,5 @@ 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