Commit 8859b0da authored by Jean-Philippe Brucker's avatar Jean-Philippe Brucker Committed by Andrii Nakryiko
Browse files

tools/bpftool: Fix cross-build 



The bpftool build first creates an intermediate binary, executed on the
host, to generate skeletons required by the final build. When
cross-building bpftool for an architecture different from the host, the
intermediate binary should be built using the host compiler (gcc) and
the final bpftool using the cross compiler (e.g. aarch64-linux-gnu-gcc).

Generate the intermediate objects into the bootstrap/ directory using
the host toolchain.

Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201110164310.2600671-4-jean-philippe@linaro.org
parent 9e8929fd

tools/bpf/bpftool/Makefile

+26 −8
Original line number Diff line number Diff line
@@ -19,24 +19,37 @@ BPF_DIR = $(srctree)/tools/lib/bpf/ 
ifneq ($(OUTPUT),)

  LIBBPF_OUTPUT = $(OUTPUT)/libbpf/

  LIBBPF_PATH = $(LIBBPF_OUTPUT)

  BOOTSTRAP_OUTPUT = $(OUTPUT)/bootstrap/

else

  LIBBPF_OUTPUT =

  LIBBPF_PATH = $(BPF_DIR)

  BOOTSTRAP_OUTPUT = $(CURDIR)/bootstrap/

endif



LIBBPF = $(LIBBPF_PATH)libbpf.a

LIBBPF_BOOTSTRAP_OUTPUT = $(BOOTSTRAP_OUTPUT)libbpf/

LIBBPF_BOOTSTRAP = $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a



BPFTOOL_VERSION ?= $(shell make -rR --no-print-directory -sC ../../.. kernelversion)



$(LIBBPF_OUTPUT):

$(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT):

	$(QUIET_MKDIR)mkdir -p $@



$(LIBBPF): FORCE | $(LIBBPF_OUTPUT)

	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) $(LIBBPF_OUTPUT)libbpf.a



$(LIBBPF_BOOTSTRAP): FORCE | $(LIBBPF_BOOTSTRAP_OUTPUT)

	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \

		ARCH= CC=$(HOSTCC) LD=$(HOSTLD) $@



$(LIBBPF)-clean: $(LIBBPF_OUTPUT)

	$(call QUIET_CLEAN, libbpf)

	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) clean >/dev/null



$(LIBBPF_BOOTSTRAP)-clean: $(LIBBPF_BOOTSTRAP_OUTPUT)

	$(call QUIET_CLEAN, libbpf-bootstrap)

	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) clean >/dev/null



prefix ?= /usr/local

bash_compdir ?= /usr/share/bash-completion/completions
@@ -94,6 +107,7 @@ CFLAGS += -DCOMPAT_NEED_REALLOCARRAY 
endif



LIBS = $(LIBBPF) -lelf -lz

LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz

ifeq ($(feature-libcap), 1)

CFLAGS += -DUSE_LIBCAP

LIBS += -lcap
@@ -120,9 +134,9 @@ CFLAGS += -DHAVE_LIBBFD_SUPPORT 
SRCS += $(BFD_SRCS)

endif



BPFTOOL_BOOTSTRAP := $(if $(OUTPUT),$(OUTPUT)bpftool-bootstrap,./bpftool-bootstrap)

BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool



BOOTSTRAP_OBJS = $(addprefix $(OUTPUT),main.o common.o json_writer.o gen.o btf.o)

BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o)

OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o



VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
@@ -169,12 +183,16 @@ $(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c 


$(OUTPUT)feature.o: | zdep



$(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF)

	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(BOOTSTRAP_OBJS) $(LIBS)

$(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP)

	$(QUIET_LINK)$(HOSTCC) $(CFLAGS) $(LDFLAGS) -o $@ $(BOOTSTRAP_OBJS) \

		$(LIBS_BOOTSTRAP)



$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)

	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)



$(BOOTSTRAP_OUTPUT)%.o: %.c | $(BOOTSTRAP_OUTPUT)

	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<



$(OUTPUT)%.o: %.c

	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
@@ -182,11 +200,11 @@ feature-detect-clean: 
	$(call QUIET_CLEAN, feature-detect)

	$(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null



clean: $(LIBBPF)-clean feature-detect-clean

clean: $(LIBBPF)-clean $(LIBBPF_BOOTSTRAP)-clean feature-detect-clean

	$(call QUIET_CLEAN, bpftool)

	$(Q)$(RM) -- $(OUTPUT)bpftool $(OUTPUT)*.o $(OUTPUT)*.d

	$(Q)$(RM) -- $(BPFTOOL_BOOTSTRAP) $(OUTPUT)*.skel.h $(OUTPUT)vmlinux.h

	$(Q)$(RM) -r -- $(OUTPUT)libbpf/

	$(Q)$(RM) -- $(OUTPUT)*.skel.h $(OUTPUT)vmlinux.h

	$(Q)$(RM) -r -- $(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT)

	$(call QUIET_CLEAN, core-gen)

	$(Q)$(RM) -- $(OUTPUT)FEATURE-DUMP.bpftool

	$(Q)$(RM) -r -- $(OUTPUT)feature/

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