Commit 5e53e5c7 authored by Björn Töpel's avatar Björn Töpel Committed by Alexei Starovoitov
Browse files

selftests/bpf: Cross-compile bpftool 



When the BPF selftests are cross-compiled, only the a host version of
bpftool is built. This version of bpftool is used on the host-side to
generate various intermediates, e.g., skeletons.

The test runners are also using bpftool, so the Makefile will symlink
bpftool from the selftest/bpf root, where the test runners will look
the tool:

  | $(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/bootstrap/bpftool \
  |    $(OUTPUT)/$(if $2,$2/)bpftool

There are two problems for cross-compilation builds:

 1. There is no native (cross-compilation target) of bpftool
 2. The bootstrap/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 the native/non-bootstrap version.

Acked-by: default avatarQuentin Monnet <quentin@isovalent.com>
Signed-off-by: default avatarBjörn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230214161253.183458-1-bjorn@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 213aacb8

tools/testing/selftests/bpf/Makefile

+26 −4
Original line number Diff line number Diff line
@@ -157,7 +157,8 @@ $(notdir $(TEST_GEN_PROGS) \ 


# 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      \

	       $(BUILD_DIR)/bpftool $(HOST_BUILD_DIR)/bpftool		\

	       $(HOST_BUILD_DIR)/resolve_btfids				\

	       $(RUNQSLOWER_OUTPUT) $(INCLUDE_DIR))

$(MAKE_DIRS):

	$(call msg,MKDIR,,$@)
@@ -207,6 +208,14 @@ $(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	       \
@@ -218,7 +227,7 @@ $(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL) $(RUNQSLOWER_OUTPUT) 
		    EXTRA_LDFLAGS='$(SAN_LDFLAGS)' &&			       \

		    cp $(RUNQSLOWER_OUTPUT)runqslower $@



TEST_GEN_PROGS_EXTENDED += $(DEFAULT_BPFTOOL)

TEST_GEN_PROGS_EXTENDED += $(TRUNNER_BPFTOOL)



$(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): $(BPFOBJ)
@@ -256,6 +265,18 @@ $(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:
@@ -521,11 +542,12 @@ 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 \

		   $(OUTPUT)/$(if $2,$2/)bpftool



endef