On Wed, Jul 20, 2022 at 05:32 PM +02, Jakub Sitnicki wrote: [...] >> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile >> index 8ad7a733a505..e08e8e34e793 100644 >> --- a/tools/testing/selftests/bpf/Makefile >> +++ b/tools/testing/selftests/bpf/Makefile >> @@ -172,13 +172,15 @@ $(OUTPUT)/%:%.c >> # do not fail. Static builds leave urandom_read relying on system-wide shared libraries. >> $(OUTPUT)/liburandom_read.so: urandom_read_lib1.c urandom_read_lib2.c >> $(call msg,LIB,,$@) >> - $(Q)$(CC) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $^ $(LDLIBS) -fPIC -shared -o $@ >> + $(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $^ $(LDLIBS) \ >> + -fuse-ld=lld -Wl,-znoseparate-code -fPIC -shared -o $@ >> >> $(OUTPUT)/urandom_read: urandom_read.c urandom_read_aux.c $(OUTPUT)/liburandom_read.so >> $(call msg,BINARY,,$@) >> - $(Q)$(CC) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter %.c,$^) \ >> - liburandom_read.so $(LDLIBS) \ >> - -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ >> + $(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter %.c,$^) \ >> + liburandom_read.so $(LDLIBS) \ >> + -fuse-ld=lld -Wl,-znoseparate-code \ >> + -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ > > [...] > > Not sure if this was considered - adding a dependency on Clang for the > target platform makes cross-compiling bpf selftests much harder than it > was. > > Maybe we could use $(CLANG) only when not cross-compiling, and execute > $(CC) like before otherwise? OTOH, there seems to be nothing Clang specific about the build recipe. We just want t use LLVM lld. GCC accepts -fuse-ld as well (bfd vs lld). Perhaps we could partially revert to something as below? It "fixes" the cross-compilation build of bpf selftests for arm64 for me. WDYT? --8<-- diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 8d59ec7f4c2d..541e2b0de27a 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -170,24 +170,24 @@ $(OUTPUT)/%:%.c # LLVM's ld.lld doesn't support all the architectures, so use it only on x86 ifeq ($(SRCARCH),x86) -LLD := lld +ALT_LD := lld else -LLD := ld +ALT_LD := bfd endif # Filter out -static for liburandom_read.so and its dependent targets so that static builds # do not fail. Static builds leave urandom_read relying on system-wide shared libraries. $(OUTPUT)/liburandom_read.so: urandom_read_lib1.c urandom_read_lib2.c $(call msg,LIB,,$@) - $(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $^ $(LDLIBS) \ - -fuse-ld=$(LLD) -Wl,-znoseparate-code -fPIC -shared -o $@ + $(Q)$(CC) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $^ $(LDLIBS) \ + -fuse-ld=$(ALT_LD) -Wl,-znoseparate-code -fPIC -shared -o $@ $(OUTPUT)/urandom_read: urandom_read.c urandom_read_aux.c $(OUTPUT)/liburandom_read.so $(call msg,BINARY,,$@) - $(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter %.c,$^) \ - liburandom_read.so $(LDLIBS) \ - -fuse-ld=$(LLD) -Wl,-znoseparate-code \ - -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ + $(Q)$(CC) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter %.c,$^) \ + liburandom_read.so $(LDLIBS) \ + -fuse-ld=$(ALT_LD) -Wl,-znoseparate-code \ + -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ $(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(wildcard bpf_testmod/Makefile bpf_testmod/*.[ch]) $(call msg,MOD,,$@)
