From 3f7a3318a7c60947e27be372950840a5eab976d0 Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Thu, 7 Oct 2021 20:44:35 +0100 Subject: [PATCH] samples/bpf: Install libbpf headers when building 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. Add a dependency on libbpf's headers for the $(TRACE_HELPERS). 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 Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211007194438.34443-10-quentin@isovalent.com --- samples/bpf/Makefile | 40 ++++++++++++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 10 deletions(-) diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index a5783749ec15..8c5311d77680 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -61,7 +61,11 @@ 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 = $(LIBBPF_OUTPUT)/libbpf.a CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o @@ -200,7 +204,7 @@ TPROGS_CFLAGS += -Wstrict-prototypes TPROGS_CFLAGS += -I$(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 @@ -270,16 +274,27 @@ all: clean: $(MAKE) -C ../../ M=$(CURDIR) clean @find $(CURDIR) -type f -name '*~' -delete + @$(RM) -r $(CURDIR)/libbpf $(CURDIR)/bpftool -$(LIBBPF): FORCE +$(LIBBPF): FORCE | $(LIBBPF_OUTPUT) # 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): $(LIBBPF) $(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) $(BPFTOOL_OUTPUT): + $(call msg,MKDIR,$@) + $(Q)mkdir -p $@ $(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE $(call filechk,offsets,__SYSCALL_NRS_H__) @@ -311,6 +326,11 @@ verify_target_bpf: verify_cmds $(BPF_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF) $(src)/*.c: verify_target_bpf $(LIBBPF) +libbpf_hdrs: $(LIBBPF) +$(obj)/$(TRACE_HELPERS): | libbpf_hdrs + +.PHONY: libbpf_hdrs + $(obj)/xdp_redirect_cpu_user.o: $(obj)/xdp_redirect_cpu.skel.h $(obj)/xdp_redirect_map_multi_user.o: $(obj)/xdp_redirect_map_multi.skel.h $(obj)/xdp_redirect_map_user.o: $(obj)/xdp_redirect_map.skel.h @@ -369,7 +389,7 @@ $(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 \ @@ -406,7 +426,7 @@ $(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 \ -- 2.11.0