Adding one more discussion around your previous question that I missed. On 7/7/23 01:09, Stanislav Fomichev wrote: > On 07/06, Anh Tuan Phan wrote: >> This commit fixes a few compilation issues when building out of source >> tree. The command that I used to build samples/bpf: >> >> export KBUILD_OUTPUT=/tmp >> make V=1 M=samples/bpf >> >> The compilation failed since it tried to find the header files in the >> wrong places between output directory and source tree directory >> >> Signed-off-by: Anh Tuan Phan <tuananhlfc@xxxxxxxxx> >> --- >> samples/bpf/Makefile | 8 ++++---- >> samples/bpf/Makefile.target | 2 +- >> 2 files changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile >> index 615f24ebc49c..32469aaa82d5 100644 >> --- a/samples/bpf/Makefile >> +++ b/samples/bpf/Makefile >> @@ -341,10 +341,10 @@ $(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h >> # Override includes for xdp_sample_user.o because $(srctree)/usr/include in >> # TPROGS_CFLAGS causes conflicts >> XDP_SAMPLE_CFLAGS += -Wall -O2 \ >> - -I$(src)/../../tools/include \ >> + -I$(srctree)/tools/include \ > > [..] > >> -I$(src)/../../tools/include/uapi \ > > Does this $(src) need to be changed as well? > > >> -I$(LIBBPF_INCLUDE) \ >> - -I$(src)/../../tools/testing/selftests/bpf >> + -I$(srctree)/tools/testing/selftests/bpf >> >> $(obj)/$(XDP_SAMPLE): TPROGS_CFLAGS = $(XDP_SAMPLE_CFLAGS) >> $(obj)/$(XDP_SAMPLE): $(src)/xdp_sample_user.h $(src)/xdp_sample_shared.h >> @@ -393,7 +393,7 @@ $(obj)/xdp_router_ipv4.bpf.o: $(obj)/xdp_sample.bpf.o >> $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h >> $(src)/xdp_sample_shared.h >> @echo " CLANG-BPF " $@ >> $(Q)$(CLANG) -g -O2 -target bpf -D__TARGET_ARCH_$(SRCARCH) \ >> - -Wno-compare-distinct-pointer-types -I$(srctree)/include \ >> + -Wno-compare-distinct-pointer-types -I$(obj) -I$(srctree)/include \ >> -I$(srctree)/samples/bpf -I$(srctree)/tools/include \ >> -I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \ >> -c $(filter %.bpf.c,$^) -o $@ >> @@ -412,7 +412,7 @@ xdp_router_ipv4.skel.h-deps := xdp_router_ipv4.bpf.o >> xdp_sample.bpf.o >> >> LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach >> skel,$(LINKED_SKELS),$($(skel)-deps))) >> >> -BPF_SRCS_LINKED := $(notdir $(wildcard $(src)/*.bpf.c)) >> +BPF_SRCS_LINKED := $(notdir $(wildcard $(srctree)/$(src)/*.bpf.c)) >> BPF_OBJS_LINKED := $(patsubst %.bpf.c,$(obj)/%.bpf.o, $(BPF_SRCS_LINKED)) >> BPF_SKELS_LINKED := $(addprefix $(obj)/,$(LINKED_SKELS)) >> >> diff --git a/samples/bpf/Makefile.target b/samples/bpf/Makefile.target >> index 7621f55e2947..86a454cfb080 100644 >> --- a/samples/bpf/Makefile.target >> +++ b/samples/bpf/Makefile.target >> @@ -41,7 +41,7 @@ _tprogc_flags = $(TPROGS_CFLAGS) \ >> $(TPROGCFLAGS_$(basetarget).o) >> >> # $(objtree)/$(obj) for including generated headers from checkin source >> files > > [..] > >> -ifeq ($(KBUILD_EXTMOD),) >> +ifneq ($(KBUILD_EXTMOD),) > > This parts seems to be copy-pasted all over the place in its 'ifeq' > form. What is it doing and why is it needed? Sorry for missing this question. As I understand KBUILD_EXTMOD corresponding to external module. In my case, it's $M=samples/bpf. I don't really know why it's needed here. > >> ifdef building_out_of_srctree >> _tprogc_flags += -I $(objtree)/$(obj) >> endif >> -- >> 2.34.1
