Re: [PATCH v3] samples/bpf: Fix build out of source tree

Anh Tuan Phan <tuananhlfc@xxxxxxxxx> · Tue, 1 Aug 2023 22:56:44 +0700

On 01/08/2023 00:17, Stanislav Fomichev wrote:
On Sun, Jul 30, 2023 at 6:18 AM Anh Tuan Phan <tuananhlfc@xxxxxxxxx> 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

Still doesn't apply cleanly, most likely due to commit bbaf1ff06af4
("bpf: Replace deprecated -target with --target= for Clang").
Please rebase and repost. Also add [PATCH bpf-next v4] tag.


I rebased the commit from bpf tree so it's the reason for your failed 
applied. Have rebased from bpf-next tree and sent a "PATCH bpf-next v4" 
patch.

Thank you!


Signed-off-by: Anh Tuan Phan <tuananhlfc@xxxxxxxxx>
---
Changes from v1:
- Unconditionally add "-I $(objtree)/$(obj)" to _tprogc_flags and drop unnecessary part
Reference:
- v1: https://lore.kernel.org/all/67bec6a9-af59-d6f9-2630-17280479a1f7@xxxxxxxxx/
- v2: https://lore.kernel.org/all/2ba1c076-f5bf-432f-50c1-72c845403167@xxxxxxxxx/
---
  samples/bpf/Makefile        | 10 +++++-----
  samples/bpf/Makefile.target |  9 +--------
  2 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 615f24ebc49c..cfc960b3713a 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$(src)/../../tools/include/uapi \
+                    -I$(srctree)/tools/include \
+                    -I$(srctree)/tools/include/uapi \
                      -I$(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..d2fab959652e 100644
--- a/samples/bpf/Makefile.target
+++ b/samples/bpf/Makefile.target
@@ -38,14 +38,7 @@ tprog-cobjs  := $(addprefix $(obj)/,$(tprog-cobjs))
  # Handle options to gcc. Support building with separate output directory

  _tprogc_flags   = $(TPROGS_CFLAGS) \
-                 $(TPROGCFLAGS_$(basetarget).o)
-
-# $(objtree)/$(obj) for including generated headers from checkin source files
-ifeq ($(KBUILD_EXTMOD),)
-ifdef building_out_of_srctree
-_tprogc_flags   += -I $(objtree)/$(obj)
-endif
-endif
+                 -I $(objtree)/$(obj)

  tprogc_flags    = -Wp,-MD,$(depfile) $(_tprogc_flags)

--
2.34.1








