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: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201110164310.2600671-4-jean-philippe@linaro.org
This commit is contained in:
Jean-Philippe Brucker 2020-11-10 17:43:07 +01:00 committed by Andrii Nakryiko
parent 9e8929fdbb
commit 8859b0da5a
1 changed files with 26 additions and 8 deletions

View File

@ -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/