[PATCH] libbpf: Fix up generation of bpf_helper_defs.h

Arnaldo Carvalho de Melo
2019-11-26T15:10:55Z

Hi guys,

While merging perf/core with mainline I found the problem below for
which I'm adding this patch to my perf/core branch, that soon will go
Ingo's way, etc. Please let me know if you think this should be handled
some other way,

Thanks,

- Arnaldo

commit 94b2e22463f592d2161eb491ddb0b4659e2a91b4
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Tue Nov 26 11:46:08 2019 -0300

libbpf: Fix up generation of bpf_helper_defs.h

Building perf as a detached tarball, i.e. by using one of:

$ make help | grep perf
perf-tar-src-pkg - Build perf-5.4.0.tar source tarball
perf-targz-src-pkg - Build perf-5.4.0.tar.gz source tarball
perf-tarbz2-src-pkg - Build perf-5.4.0.tar.bz2 source tarball
perf-tarxz-src-pkg - Build perf-5.4.0.tar.xz source tarball
$

And then trying to build the resulting tarball, which is the first thing
that running:

$ make -C tools/perf build-test

does, ends up with these two problems:

make[3]: *** No rule to make target '/tmp/tmp.zq13cHILGB/perf-5.3.0/include/uapi/linux/bpf.h', needed by 'bpf_helper_defs.h'. Stop.
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [Makefile.perf:757: /tmp/tmp.zq13cHILGB/perf-5.3.0/tools/lib/bpf/libbpf.a] Error 2
make[2]: *** Waiting for unfinished jobs....

Because $(srcdir) points to the /tmp/tmp.zq13cHILGB/perf-5.3.0 directory
and we need '/tools/ after that variable, and after fixing this then we
get to another problem:

/bin/sh: /home/acme/git/perf/tools/scripts/bpf_helpers_doc.py: No such file or directory
make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 127
make[3]: *** Deleting file 'bpf_helper_defs.h'
LD /tmp/build/perf/libapi-in.o
make[2]: *** [Makefile.perf:778: /tmp/build/perf/libbpf.a] Error 2
make[2]: *** Waiting for unfinished jobs....

Because this requires something outside the tools/ directories that gets
collected into perf's detached tarballs, to fix it just add it to
tools/perf/MANIFEST, which this patch does, now it works for that case
and also for all these other cases after doing a:

$ make -C tools clean

On a kernel sources directory:

$ make -C tools/bpf/bpftool/
make: Entering directory '/home/acme/git/perf/tools/bpf/bpftool'

Auto-detecting system features:
... libbfd: [ on ]
... disassembler-four-args: [ on ]
... zlib: [ on ]

CC map_perf_ring.o
<SNIP>
CC disasm.o
make[1]: Entering directory '/home/acme/git/perf/tools/lib/bpf'

Auto-detecting system features:
... libelf: [ on ]
... bpf: [ on ]

MKDIR staticobjs/
CC staticobjs/libbpf.o
<SNIP>
LD staticobjs/libbpf-in.o
LINK libbpf.a
make[1]: Leaving directory '/home/acme/git/perf/tools/lib/bpf'
LINK bpftool
make: Leaving directory '/home/acme/git/perf/tools/bpf/bpftool'
$

$ make -C tools/perf
<SNIP>
Auto-detecting system features:
... dwarf: [ on ]
... dwarf_getlocations: [ on ]
... glibc: [ on ]
... gtk2: [ on ]
... libaudit: [ on ]
... libbfd: [ on ]
... libcap: [ on ]
... libelf: [ on ]
... libnuma: [ on ]
... numa_num_possible_cpus: [ on ]
... libperl: [ on ]
... libpython: [ on ]
... libcrypto: [ on ]
... libunwind: [ on ]
... libdw-dwarf-unwind: [ on ]
... zlib: [ on ]
... lzma: [ on ]
... get_cpuid: [ on ]
... bpf: [ on ]
... libaio: [ on ]
... libzstd: [ on ]
... disassembler-four-args: [ on ]

GEN common-cmds.h
CC exec-cmd.o
<SNIP>
CC util/pmu.o
CC util/pmu-flex.o
LD util/perf-in.o
LD perf-in.o
LINK perf
make: Leaving directory '/home/acme/git/perf/tools/perf'
$

$ make -C tools/lib/bpf
make: Entering directory '/home/acme/git/perf/tools/lib/bpf'

Auto-detecting system features:
... libelf: [ on ]
... bpf: [ on ]

HOSTCC fixdep.o
HOSTLD fixdep-in.o
LINK fixdep
Parsed description of 117 helper function(s)
MKDIR staticobjs/
CC staticobjs/libbpf.o
CC staticobjs/bpf.o
CC staticobjs/nlattr.o
CC staticobjs/btf.o
CC staticobjs/libbpf_errno.o
CC staticobjs/str_error.o
CC staticobjs/netlink.o
CC staticobjs/bpf_prog_linfo.o
CC staticobjs/libbpf_probes.o
CC staticobjs/xsk.o
CC staticobjs/hashmap.o
CC staticobjs/btf_dump.o
LD staticobjs/libbpf-in.o
LINK libbpf.a
MKDIR sharedobjs/
CC sharedobjs/libbpf.o
CC sharedobjs/bpf.o
CC sharedobjs/nlattr.o
CC sharedobjs/btf.o
CC sharedobjs/libbpf_errno.o
CC sharedobjs/str_error.o
CC sharedobjs/netlink.o
CC sharedobjs/bpf_prog_linfo.o
CC sharedobjs/libbpf_probes.o
CC sharedobjs/xsk.o
CC sharedobjs/hashmap.o
CC sharedobjs/btf_dump.o
LD sharedobjs/libbpf-in.o
LINK libbpf.so.0.0.6
GEN libbpf.pc
LINK test_libbpf
make: Leaving directory '/home/acme/git/perf/tools/lib/bpf'
$

Fixes: e01a75c15969 ("libbpf: Move bpf_{helpers, helper_defs, endian, tracing}.h into libbpf")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-4pnkg2vmdvq5u6eivc887wen@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 99425d0be6ff..8ec6bc4e5e46 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -180,9 +180,9 @@ $(BPF_IN_SHARED): force elfdep bpfdep bpf_helper_defs.h
$(BPF_IN_STATIC): force elfdep bpfdep bpf_helper_defs.h
$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR)

-bpf_helper_defs.h: $(srctree)/include/uapi/linux/bpf.h
+bpf_helper_defs.h: $(srctree)/tools/include/uapi/linux/bpf.h
$(Q)$(srctree)/scripts/bpf_helpers_doc.py --header \
- --file $(srctree)/include/uapi/linux/bpf.h > bpf_helper_defs.h
+ --file $(srctree)/tools/include/uapi/linux/bpf.h > bpf_helper_defs.h

$(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)

diff --git a/tools/perf/MANIFEST b/tools/perf/MANIFEST
index 70f1ff4e2eb4..4934edb5adfd 100644
--- a/tools/perf/MANIFEST
+++ b/tools/perf/MANIFEST
@@ -19,3 +19,4 @@ tools/lib/bitmap.c
tools/lib/str_error_r.c
tools/lib/vsprintf.c
tools/lib/zalloc.c
+scripts/bpf_helpers_doc.py