From: Nathan Chancellor natechancellor@gmail.com
commit 76d7fff22be3e4185ee5f9da2eecbd8188e76b2c upstream.
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 Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de [nc: Fix conflict due to lack of 99570c3da96a and 076f421da5d4 in 4.19] Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/mips/vdso/Makefile | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
--- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -10,12 +10,9 @@ ccflags-vdso := \ $(filter -march=%,$(KBUILD_CFLAGS)) \ $(filter -m%-float,$(KBUILD_CFLAGS)) \ $(filter -mno-loongson-%,$(KBUILD_CFLAGS)) \ + $(CLANG_FLAGS) \ -D__VDSO__
-ifeq ($(cc-name),clang) -ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS)) -endif - cflags-vdso := $(ccflags-vdso) \ $(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \ -O2 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \