2023-02-10 09:43 UTC+0100 ~ Björn Töpel <bjorn@xxxxxxxxxx> > From: Björn Töpel <bjorn@xxxxxxxxxxxx> > > When the BPF selftests are cross-compiled, only the a host version of > bpftool is built. This version of bpftool is used to generate various > intermediates, e.g., skeletons. > > The test runners are also using bpftool. The Makefile will symlink > bpftool from the selftest/bpf root, where the test runners will look > for the tool: > > | ... > | $(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/bootstrap/bpftool \ > | $(OUTPUT)/$(if $2,$2/)bpftool > > There are two issues for cross-compilation builds: > > 1. There is no native (cross-compilation target) build of bpftool > 2. The bootstrap variant of bpftool is never cross-compiled (by > design) > > Make sure that a native/cross-compiled version of bpftool is built, > and if CROSS_COMPILE is set, symlink to the native/non-bootstrap > version. > > Signed-off-by: Björn Töpel <bjorn@xxxxxxxxxxxx> > --- > tools/testing/selftests/bpf/Makefile | 28 +++++++++++++++++++++++++--- > 1 file changed, 25 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile > index b2eb3201b85a..b706750f71e2 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -157,8 +157,9 @@ $(notdir $(TEST_GEN_PROGS) \ > $(TEST_CUSTOM_PROGS)): %: $(OUTPUT)/% ; > > # sort removes libbpf duplicates when not cross-building > -MAKE_DIRS := $(sort $(BUILD_DIR)/libbpf $(HOST_BUILD_DIR)/libbpf \ > - $(HOST_BUILD_DIR)/bpftool $(HOST_BUILD_DIR)/resolve_btfids \ > +MAKE_DIRS := $(sort $(BUILD_DIR)/libbpf $(HOST_BUILD_DIR)/libbpf \ > + $(BUILD_DIR)/bpftool $(HOST_BUILD_DIR)/bpftool \ > + $(HOST_BUILD_DIR)/resolve_btfids \ > $(RUNQSLOWER_OUTPUT) $(INCLUDE_DIR)) > $(MAKE_DIRS): > $(call msg,MKDIR,,$@) > @@ -208,6 +209,14 @@ $(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(wildcard bpf_testmod/Makefile bpf_tes > $(Q)cp bpf_testmod/bpf_testmod.ko $@ > > DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool > +ifneq ($(CROSS_COMPILE),) > +CROSS_BPFTOOL := $(SCRATCH_DIR)/sbin/bpftool > +TRUNNER_BPFTOOL := $(CROSS_BPFTOOL) > +USE_BOOTSTRAP := "" > +else > +TRUNNER_BPFTOOL := $(DEFAULT_BPFTOOL) > +USE_BOOTSTRAP := "bootstrap" > +endif > > $(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL) $(RUNQSLOWER_OUTPUT) > $(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/runqslower \ > @@ -255,6 +264,18 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ > LIBBPF_DESTDIR=$(HOST_SCRATCH_DIR)/ \ > prefix= DESTDIR=$(HOST_SCRATCH_DIR)/ install-bin > > +ifneq ($(CROSS_COMPILE),) > +$(CROSS_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ > + $(BPFOBJ) | $(BUILD_DIR)/bpftool > + $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \ > + ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) \ > + EXTRA_CFLAGS='-g -O0' \ > + OUTPUT=$(BUILD_DIR)/bpftool/ \ > + LIBBPF_OUTPUT=$(BUILD_DIR)/libbpf/ \ > + LIBBPF_DESTDIR=$(SCRATCH_DIR)/ \ > + prefix= DESTDIR=$(SCRATCH_DIR)/ install-bin > +endif > + > all: docs > > docs: > @@ -518,11 +539,12 @@ endif > $(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS) \ > $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ) \ > $(RESOLVE_BTFIDS) \ > + $(TRUNNER_BPFTOOL) \ > | $(TRUNNER_BINARY)-extras > $$(call msg,BINARY,,$$@) > $(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) -o $$@ > $(Q)$(RESOLVE_BTFIDS) --btf $(TRUNNER_OUTPUT)/btf_data.bpf.o $$@ > - $(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/bootstrap/bpftool \ > + $(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/$(USE_BOOTSTRAP)/bpftool \ Nit: You'll have a double slash in this path when USE_BOOSTRAP is empty (.../tools/build/bpftool//bpftool), but it probably doesn't matter much. > $(OUTPUT)/$(if $2,$2/)bpftool > > endef > > base-commit: 06744f24696e1e7598412c3df61a538b57ebec22 The changes look good to me, thanks! Acked-by: Quentin Monnet <quentin@xxxxxxxxxxxxx> Jean-Philippe, I know you do some cross-compiling with bpftool, how does this look from your side?
