[PATCH bpf-next v2 5/9] bpf: preload: install libbpf headers when building
flat view
STALE1829d
From: Quentin Monnet <hidden>
Date: 2021-10-01 11:13:33
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Revision v2 of 4 in this series.
Revisions (4)
- v1 [diff vs current]
- v2 current
- v3 [diff vs current]
- v4 [diff vs current]
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 <redacted> --- kernel/bpf/preload/Makefile | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
index 1951332dd15f..e6a94278b935 100644
--- a/kernel/bpf/preload/Makefile
+++ b/kernel/bpf/preload/Makefile@@ -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
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2.30.2