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

Alexei Starovoitov
2019-11-26T16:54:10Z

On Tue, Nov 26, 2019 at 7:10 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> 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

fwiw. this bit looks good. Makes sense to do regardless.

> $(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

This one I don't understand. I couldn't find any piece that uses this file.
Some out of tree usage?