On 9/10/19 11:38 AM, Ivan Khoronzhuk wrote: > In case of LDFLAGS and EXTRA_CC/CXX flags there is no way to pass them > correctly to build command, for instance when --sysroot is used or > external libraries are used, like -lelf, wich can be absent in > toolchain. This is used for samples/bpf cross-compiling allowing to > get elf lib from sysroot. > > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> > --- > samples/bpf/Makefile | 8 +++++++- > tools/lib/bpf/Makefile | 11 ++++++++--- > 2 files changed, 15 insertions(+), 4 deletions(-) Could you separate this patch into two? One of libbpf and another for samples. The subject 'libbpf: ...' is not entirely accurate. > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile > index 79c9aa41832e..4edc5232cfc1 100644 > --- a/samples/bpf/Makefile > +++ b/samples/bpf/Makefile > @@ -186,6 +186,10 @@ ccflags-y += -I$(srctree)/tools/perf > ccflags-y += $(D_OPTIONS) > ccflags-y += -Wall > ccflags-y += -fomit-frame-pointer > + > +EXTRA_CXXFLAGS := $(ccflags-y) > + > +# options not valid for C++ > ccflags-y += -Wmissing-prototypes > ccflags-y += -Wstrict-prototypes > > @@ -252,7 +256,9 @@ clean: > > $(LIBBPF): FORCE > # Fix up variables inherited from Kbuild that tools/ build system won't like > - $(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O= > + $(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(PROGS_CFLAGS)" \ > + EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(PROGS_LDFLAGS) \ > + srctree=$(BPF_SAMPLES_PATH)/../../ O= > > $(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE > $(call filechk,offsets,__SYSCALL_NRS_H__) > diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile > index c6f94cffe06e..bccfa556ef4e 100644 > --- a/tools/lib/bpf/Makefile > +++ b/tools/lib/bpf/Makefile > @@ -94,6 +94,10 @@ else > CFLAGS := -g -Wall > endif > > +ifdef EXTRA_CXXFLAGS > + CXXFLAGS := $(EXTRA_CXXFLAGS) > +endif > + > ifeq ($(feature-libelf-mmap), 1) > override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT > endif > @@ -176,8 +180,9 @@ $(BPF_IN): force elfdep bpfdep > $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION) > > $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN) > - $(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \ > - -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@ > + $(QUIET_LINK)$(CC) $(LDFLAGS) \ > + --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \ > + -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@ > @ln -sf $(@F) $(OUTPUT)libbpf.so > @ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION) > > @@ -185,7 +190,7 @@ $(OUTPUT)libbpf.a: $(BPF_IN) > $(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^ > > $(OUTPUT)test_libbpf: test_libbpf.cpp $(OUTPUT)libbpf.a > - $(QUIET_LINK)$(CXX) $(INCLUDES) $^ -lelf -o $@ > + $(QUIET_LINK)$(CXX) $(CXXFLAGS) $(LDFLAGS) $(INCLUDES) $^ -lelf -o $@ > > $(OUTPUT)libbpf.pc: > $(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \ >
