On Fri, Oct 25, 2019 at 11:51 AM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> When cross-compiling tests from x86 to s390, the resulting BPF objects
> fail to load due to endianness mismatch.
>
> Fix by using BPF-GCC endianness check for clang as well.
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/Makefile | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 11ff34e7311b..59b93a5667c8 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -131,10 +131,16 @@ $(shell $(1) -v -E - </dev/null 2>&1 \
> | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }')
> endef
>
> +# Determine target endianness.
> +IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \
> + grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
> +MENDIAN=$(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
> +
> CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
> BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) \
> -I. -I./include/uapi -I$(APIDIR) \
> - -I$(BPFDIR) -I$(abspath $(OUTPUT)/../usr/include)
> + -I$(BPFDIR) -I$(abspath $(OUTPUT)/../usr/include) \
> + $(MENDIAN)
minor nit: I'd put $(MENDIAN) next to -g and -D__TARGET_ARCH stuff and
keep a list of -Is at the end.
But besides that:
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
>
> CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) \
> -Wno-compare-distinct-pointer-types
> @@ -271,12 +277,8 @@ $(eval $(call DEFINE_TEST_RUNNER,test_progs,no_alu32))
>
> # Define test_progs BPF-GCC-flavored test runner.
> ifneq ($(BPF_GCC),)
> -IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - </dev/null | \
> - grep 'define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__')
> -MENDIAN=$(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
> -
> TRUNNER_BPF_BUILD_RULE := GCC_BPF_BUILD_RULE
> -TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(call get_sys_includes,gcc) $(MENDIAN)
> +TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(call get_sys_includes,gcc)
> TRUNNER_BPF_LDFLAGS :=
> $(eval $(call DEFINE_TEST_RUNNER,test_progs,bpf_gcc))
> endif
> --
> 2.23.0
>
