samples: bpf: fix build after move to compiling full libbpf.a (787360f8) · Commits · 戴 / test

There are many ways users may compile samples, some of them got broken by commit ("samples: bpf: compile and link against full libbpf"). Improve path resolution and make libbpf building a dependency of source files to force its build. Samples should now again build with any of: cd samples/bpf; make make samples/bpf/ make -C samples/bpf cd samples/bpf; make O=builddir make samples/bpf/ O=builddir make -C samples/bpf O=builddir export KBUILD_OUTPUT=builddir make samples/bpf/ make -C samples/bpf Fixes: ("samples: bpf: compile and link against full libbpf") Reported-by:

Björn Töpel <bjorn.topel@gmail.com> Signed-off-by:

Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by:

Alexei Starovoitov <ast@kernel.org>

samples/bpf/Makefile

+12 −5

Original line number	Diff line number	Diff line
		# SPDX-License-Identifier: GPL-2.0

		BPF_SAMPLES_PATH ?= $(abspath $(srctree)/$(src))
		TOOLS_PATH := $(BPF_SAMPLES_PATH)/../../tools

		# List of programs to build
		hostprogs-y := test_lru_dist
		hostprogs-y += sock_example
		@@ -49,7 +53,8 @@ hostprogs-y += xdpsock
		hostprogs-y += xdp_fwd

		# Libbpf dependencies
		LIBBPF := ../../tools/lib/bpf/libbpf.a
		LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a

		CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o
		TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o

		@@ -233,15 +238,16 @@ CLANG_ARCH_ARGS = -target $(ARCH)
		endif

		# Trick to allow make to be run from this directory
		all: $(LIBBPF)
		$(MAKE) -C ../../ $(CURDIR)/
		all:
		$(MAKE) -C ../../ $(CURDIR)/ BPF_SAMPLES_PATH=$(CURDIR)

		clean:
		$(MAKE) -C ../../ M=$(CURDIR) clean
		@rm -f *~

		$(LIBBPF): FORCE
		$(MAKE) -C $(dir $@)
		# 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=

		$(obj)/syscall_nrs.s: $(src)/syscall_nrs.c
		$(call if_changed_dep,cc_s_c)
		@@ -272,7 +278,8 @@ verify_target_bpf: verify_cmds
		exit 2; \
		else true; fi

		$(src)/*.c: verify_target_bpf
		$(BPF_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
		$(src)/*.c: verify_target_bpf $(LIBBPF)

		$(obj)/tracex5_kern.o: $(obj)/syscall_nrs.h

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