WSL2-Linux-Kernel/tools/build/feature
Arnaldo Carvalho de Melo df76e00383 perf build: Stop using __weak bpf_map_create() to handle older libbpf versions
By adding a feature test for bpf_map_create() and providing a fallback if
it isn't present in older versions of libbpf.

This also fixes the build with torvalds/master at this point:

  $ git log --oneline -5 torvalds/master
  babf0bb978 (torvalds/master) Merge tag 'xfs-5.19-for-linus' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
  e375780b63 Merge tag 'fsnotify_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
  8b728edc5b Merge tag 'fs_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
  3f306ea2e1 Merge tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping
  fbe86daca0 Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
  $

Coping with:

  $ git log --oneline -2 d16495a982
  d16495a982 libbpf: remove bpf_create_map*() APIs
  e2371b1632 libbpf: start 1.0 development cycle
  $

As the __weak function fails to build as it calls the now removed
bpf_create_map() API.

Testing:

  $ rpm -q libbpf-devel
  libbpf-devel-0.4.0-2.fc35.x86_64
  $
  $ make -C tools/perf BUILD_BPF_SKEL=1 LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
  $ cat /tmp/build/perf/feature/test-libbpf-bpf_map_create.make.output
  test-libbpf-bpf_map_create.c: In function ‘main’:
  test-libbpf-bpf_map_create.c:6:16: error: implicit declaration of function ‘bpf_map_create’; did you mean ‘bpf_map_freeze’? [-Werror=implicit-function-declaration]
      6 |         return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
        |                ^~~~~~~~~~~~~~
        |                bpf_map_freeze
  test-libbpf-bpf_map_create.c:6:87: error: expected expression before ‘,’ token
      6 |         return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
        |                                                                                       ^
  cc1: all warnings being treated as errors
  $
  $ objdump -dS /tmp/build/perf/perf | grep '<bpf_map_create>:' -A20
  000000000058b290 <bpf_map_create>:
  {
    58b290:	55                   	push   %rbp
    58b291:	48 89 e5             	mov    %rsp,%rbp
    58b294:	48 83 ec 10          	sub    $0x10,%rsp
    58b298:	64 48 8b 04 25 28 00 	mov    %fs:0x28,%rax
    58b29f:	00 00
    58b2a1:	48 89 45 f8          	mov    %rax,-0x8(%rbp)
    58b2a5:	31 c0                	xor    %eax,%eax
  	return bpf_create_map(map_type, key_size, value_size, max_entries, 0);
    58b2a7:	48 8b 45 f8          	mov    -0x8(%rbp),%rax
    58b2ab:	64 48 2b 04 25 28 00 	sub    %fs:0x28,%rax
    58b2b2:	00 00
    58b2b4:	75 10                	jne    58b2c6 <bpf_map_create+0x36>
  }
    58b2b6:	c9                   	leave
    58b2b7:	89 d6                	mov    %edx,%esi
    58b2b9:	89 ca                	mov    %ecx,%edx
    58b2bb:	44 89 c1             	mov    %r8d,%ecx
  	return bpf_create_map(map_type, key_size, value_size, max_entries, 0);
    58b2be:	45 31 c0             	xor    %r8d,%r8d
  $

Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lore.kernel.org/linux-perf-users/Yo+XvQNKL4K5khl2@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-05-26 12:36:56 -03:00
..
.gitignore
Makefile perf build: Stop using __weak bpf_map_create() to handle older libbpf versions 2022-05-26 12:36:56 -03:00
test-all.c tools build: Remove needless libpython-version feature check that breaks test-all fast path 2021-12-06 21:57:53 -03:00
test-backtrace.c
test-bionic.c
test-bpf.c bpf, mips: Fix build errors about __NR_bpf undeclared 2021-11-26 22:11:25 +01:00
test-clang-bpf-co-re.c
test-clang.cpp
test-compile.c
test-cplus-demangle.c
test-cxx.cpp
test-disassembler-four-args.c
test-dwarf.c
test-dwarf_getlocations.c
test-eventfd.c
test-file-handle.c
test-fortify-source.c
test-get_cpuid.c
test-get_current_dir_name.c
test-gettid.c
test-glibc.c
test-gtk2-infobar.c
test-gtk2.c
test-hello.c
test-jvmti-cmlr.c
test-jvmti.c
test-libaio.c
test-libaudit.c
test-libbabeltrace.c
test-libbfd-buildid.c
test-libbfd.c
test-libbpf-bpf_map_create.c perf build: Stop using __weak bpf_map_create() to handle older libbpf versions 2022-05-26 12:36:56 -03:00
test-libbpf-bpf_object__next_map.c perf build: Stop using __weak bpf_object__next_map() to handle older libbpf versions 2022-05-26 11:02:02 -03:00
test-libbpf-bpf_object__next_program.c perf build: Stop using __weak bpf_object__next_program() to handle older libbpf versions 2022-05-26 11:02:02 -03:00
test-libbpf-bpf_prog_load.c perf build: Stop using __weak bpf_prog_load() to handle older libbpf versions 2022-05-26 11:02:02 -03:00
test-libbpf-btf__load_from_kernel_by_id.c perf build: Fix btf__load_from_kernel_by_id() feature check 2022-05-26 11:02:02 -03:00
test-libbpf-btf__raw_data.c perf build: Stop using __weak btf__raw_data() to handle older libbpf versions 2022-05-26 11:02:02 -03:00
test-libbpf.c
test-libcap.c
test-libcrypto.c
test-libdebuginfod.c
test-libdw-dwarf-unwind.c
test-libelf-gelf_getnote.c
test-libelf-getphdrnum.c
test-libelf-getshdrstrndx.c
test-libelf.c
test-libnuma.c
test-libopencsd.c perf cs-etm: Update OpenCSD decoder for ETE 2021-09-03 08:16:00 -03:00
test-libperl.c
test-libpfm4.c
test-libpython.c
test-libslang-include-subdir.c
test-libslang.c
test-libtraceevent.c
test-libtracefs.c perf tools: Enable libtracefs dynamic linking 2021-09-28 16:08:37 -03:00
test-libunwind-aarch64.c
test-libunwind-arm.c
test-libunwind-debug-frame-aarch64.c
test-libunwind-debug-frame-arm.c
test-libunwind-debug-frame.c
test-libunwind-x86.c
test-libunwind-x86_64.c
test-libunwind.c
test-libzstd.c
test-llvm-version.cpp
test-llvm.cpp
test-lzma.c
test-numa_num_possible_cpus.c
test-pthread-attr-setaffinity-np.c
test-pthread-barrier.c
test-reallocarray.c
test-sched_getcpu.c
test-sdt.c
test-setns.c
test-stackprotector-all.c
test-timerfd.c
test-zlib.c