[PATCH bpf-next v2 7/9] samples/bpf: install libbpf headers when building
From: Quentin Monnet <hidden>
Date: 2021-10-01 11:13:40
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
API headers from libbpf should not be accessed directly from the source
directory. Instead, they should be exported with "make install_headers".
Make sure that samples/bpf/Makefile installs the headers properly when
building.
The object compiled from and exported by libbpf are now placed into a
subdirectory of sample/bpf/ instead of remaining in tools/lib/bpf/. We
attempt to remove this directory on "make clean". However, the "clean"
target re-enters the samples/bpf/ directory from the root of the
repository ("$(MAKE) -C ../../ M=$(CURDIR) clean"), in such a way that
$(srctree) and $(src) are not defined, making it impossible to use
$(LIBBPF_OUTPUT) and $(LIBBPF_DESTDIR) in the recipe. So we only attempt
to clean $(CURDIR)/libbpf, which is the default value.
We also change the output directory for bpftool, to place the generated
objects under samples/bpf/bpftool/ instead of building in bpftool's
directory directly. Doing so, we make sure bpftool reuses the libbpf
library previously compiled and installed.
Signed-off-by: Quentin Monnet <redacted>
---
samples/bpf/Makefile | 36 ++++++++++++++++++++++++++----------
1 file changed, 26 insertions(+), 10 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 4dc20be5fb96..7de602c2c705 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile@@ -59,7 +59,11 @@ tprogs-y += xdp_redirect tprogs-y += xdp_monitor # Libbpf dependencies -LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a +LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf +LIBBPF_OUTPUT = $(abspath $(BPF_SAMPLES_PATH))/libbpf +LIBBPF_DESTDIR = $(LIBBPF_OUTPUT) +LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include +LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o
@@ -198,7 +202,7 @@ TPROGS_CFLAGS += -Wstrict-prototypes TPROGS_CFLAGS += -I$(objtree)/usr/include TPROGS_CFLAGS += -I$(srctree)/tools/testing/selftests/bpf/ -TPROGS_CFLAGS += -I$(srctree)/tools/lib/ +TPROGS_CFLAGS += -I$(LIBBPF_INCLUDE) TPROGS_CFLAGS += -I$(srctree)/tools/include TPROGS_CFLAGS += -I$(srctree)/tools/perf TPROGS_CFLAGS += -DHAVE_ATTR_TEST=0
@@ -268,16 +272,28 @@ all: clean: $(MAKE) -C ../../ M=$(CURDIR) clean @find $(CURDIR) -type f -name '*~' -delete + @/bin/rm -rf $(CURDIR)/libbpf $(CURDIR)/bpftool -$(LIBBPF): FORCE +$(LIBBPF): FORCE | $(LIBBPF_OUTPUT) $(LIBBPF_INCLUDE) # Fix up variables inherited from Kbuild that tools/ build system won't like - $(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \ - LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(BPF_SAMPLES_PATH)/../../ O= + $(MAKE) -C $(LIBBPF_SRC) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \ + LDFLAGS=$(TPROGS_LDFLAGS) srctree=$(BPF_SAMPLES_PATH)/../../ \ + O= OUTPUT=$(LIBBPF_OUTPUT)/ DESTDIR=$(LIBBPF_DESTDIR) prefix= \ + $@ install_headers BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool -BPFTOOL := $(BPFTOOLDIR)/bpftool -$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) - $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ +BPFTOOL_OUTPUT := $(abspath $(BPF_SAMPLES_PATH))/bpftool +BPFTOOL := $(BPFTOOL_OUTPUT)/bpftool +$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ + | $(BPFTOOL_OUTPUT) + $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ \ + OUTPUT=$(BPFTOOL_OUTPUT)/ \ + LIBBPF_OUTPUT=$(LIBBPF_OUTPUT) \ + LIBBPF_DESTDIR=$(LIBBPF_DESTDIR) + +$(LIBBPF_OUTPUT) $(LIBBPF_INCLUDE) $(BPFTOOL_OUTPUT): + $(call msg,MKDIR,$@) + $(Q)mkdir -p $@ $(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE $(call filechk,offsets,__SYSCALL_NRS_H__)
@@ -367,7 +383,7 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/x $(Q)$(CLANG) -g -O2 -target bpf -D__TARGET_ARCH_$(SRCARCH) \ -Wno-compare-distinct-pointer-types -I$(srctree)/include \ -I$(srctree)/samples/bpf -I$(srctree)/tools/include \ - -I$(srctree)/tools/lib $(CLANG_SYS_INCLUDES) \ + -I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES) \ -c $(filter %.bpf.c,$^) -o $@ LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect_map_multi.skel.h \
@@ -404,7 +420,7 @@ $(obj)/%.o: $(src)/%.c @echo " CLANG-bpf " $@ $(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS) \ -I$(obj) -I$(srctree)/tools/testing/selftests/bpf/ \ - -I$(srctree)/tools/lib/ \ + -I$(LIBBPF_INCLUDE) \ -D__KERNEL__ -D__BPF_TRACING__ -Wno-unused-value -Wno-pointer-sign \ -D__TARGET_ARCH_$(SRCARCH) -Wno-compare-distinct-pointer-types \ -Wno-gnu-variable-sized-type-not-at-end \
--
2.30.2