@@ -1,21 +1,36 @@
# SPDX-License-Identifier: GPL-2.0
LIBBPF_SRCS = $(srctree)/tools/lib/bpf/
-LIBBPF_A = $(obj)/libbpf.a
-LIBBPF_OUT = $(abspath $(obj))
+LIBBPF_OUT = $(abspath $(obj))/libbpf
+LIBBPF_A = $(LIBBPF_OUT)/libbpf.a
+LIBBPF_DESTDIR = $(LIBBPF_OUT)
+LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
# Although not in use by libbpf's Makefile, set $(O) so that the "dummy" test
# in tools/scripts/Makefile.include always succeeds when building the kernel
# with $(O) pointing to a relative path, as in "make O=build bindeb-pkg".
-$(LIBBPF_A):
- $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
+$(LIBBPF_A): | $(LIBBPF_OUT) $(LIBBPF_INCLUDE)
+ $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ \
+ DESTDIR=$(LIBBPF_DESTDIR) prefix= \
+ $(LIBBPF_OUT)/libbpf.a install_headers
+
+libbpf-hdrs: $(LIBBPF_A)
+
+.PHONY: libbpf-hdrs
+
+$(LIBBPF_OUT) $(LIBBPF_INCLUDE):
+ $(call msg,MKDIR,$@)
+ $(Q)mkdir -p $@
userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
- -I $(srctree)/tools/lib/ -Wno-unused-result
+ -I $(LIBBPF_INCLUDE) -Wno-unused-result
userprogs := bpf_preload_umd
clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/
+clean-files += $(LIBBPF_OUT) $(LIBBPF_DESTDIR)
+
+$(obj)/iterators/iterators.o: libbpf-hdrs
bpf_preload_umd-objs := iterators/iterators.o
bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz
API headers from libbpf should not be accessed directly from the library's source directory. Instead, they should be exported with "make install_headers". Let's make sure that bpf/preload/Makefile installs the headers properly when building. Note that we declare an additional dependency for iterators/iterators.o: having $(LIBBPF_A) as a dependency to "$(obj)/bpf_preload_umd" is not sufficient, as it makes it required only at the linking step. But we need libbpf to be compiled, and in particular its headers to be exported, before we attempt to compile iterators.o. The issue would not occur before this commit, because libbpf's headers were not exported and were always available under tools/lib/bpf. Signed-off-by: Quentin Monnet <quentin@isovalent.com> --- kernel/bpf/preload/Makefile | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)