On Fri, 15 Jan 2021 at 20:26, Nathan Chancellor natechancellor@gmail.com wrote:
Commit ee67855ecd9d ("MIPS: vdso: Allow clang's --target flag in VDSO cflags") allowed the '--target=' flag from the main Makefile to filter through to the vDSO. However, it did not bring any of the other clang specific flags for controlling the integrated assembler and the GNU tools locations (--prefix=, --gcc-toolchain=, and -no-integrated-as). Without these, we will get a warning (visible with tinyconfig):
arch/mips/vdso/elf.S:14:1: warning: DWARF2 only supports one section per compilation unit .pushsection .note.Linux, "a",@note ; .balign 4 ; .long 2f - 1f ; .long 4484f - 3f ; .long 0 ; 1:.asciz "Linux" ; 2:.balign 4 ; 3: ^ arch/mips/vdso/elf.S:34:2: warning: DWARF2 only supports one section per compilation unit .section .mips_abiflags, "a" ^
All of these flags are bundled up under CLANG_FLAGS in the main Makefile and exported so that they can be added to Makefiles that set their own CFLAGS. Use this value instead of filtering out '--target=' so there is no warning and all of the tools are properly used.
Cc: stable@vger.kernel.org Fixes: ee67855ecd9d ("MIPS: vdso: Allow clang's --target flag in VDSO cflags") Link: https://github.com/ClangBuiltLinux/linux/issues/1256 Reported-by: Anders Roxell anders.roxell@linaro.org Signed-off-by: Nathan Chancellor natechancellor@gmail.com
Tested-by: Anders Roxell anders.roxell@linaro.org
Cheers, Anders
arch/mips/vdso/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 5810cc12bc1d..2131d3fd7333 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -16,16 +16,13 @@ ccflags-vdso := \ $(filter -march=%,$(KBUILD_CFLAGS)) \ $(filter -m%-float,$(KBUILD_CFLAGS)) \ $(filter -mno-loongson-%,$(KBUILD_CFLAGS)) \
$(CLANG_FLAGS) \ -D__VDSO__ifndef CONFIG_64BIT ccflags-vdso += -DBUILD_VDSO32 endif
-ifdef CONFIG_CC_IS_CLANG -ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS)) -endif
# # The -fno-jump-tables flag only prevents the compiler from generating # jump tables but does not prevent the compiler from emitting absolute
base-commit: 7b490a8ab0f2d3ab8d838a4ff22ae86edafd34a1
2.30.0