Jiri Olsa
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739c9180cf
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perf build: Stop using __weak bpf_object__next_map() to handle older libbpf versions
By adding a feature test for bpf_object__next_map() and providing a fallback if
it isn't present in older versions of libbpf.
Committer testing:
$ rpm -q libbpf-devel
libbpf-devel-0.4.0-2.fc35.x86_64
$ make -C tools/perf LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
$ cat /tmp/build/perf/feature/test-libbpf-bpf_object__next_map.make.output
test-libbpf-bpf_object__next_map.c: In function ‘main’:
test-libbpf-bpf_object__next_map.c:6:9: error: implicit declaration of function ‘bpf_object__next_map’; did you mean ‘bpf_object__next’? [-Werror=implicit-function-declaration]
6 | bpf_object__next_map(NULL /* obj */, NULL /* prev */);
| ^~~~~~~~~~~~~~~~~~~~
| bpf_object__next
cc1: all warnings being treated as errors
$
$ objdump -dS /tmp/build/perf/perf | grep '<bpf_object__next_map>:' -A20
00000000005b2e00 <bpf_object__next_map>:
{
5b2e00: 55 push %rbp
5b2e01: 48 89 e5 mov %rsp,%rbp
5b2e04: 48 83 ec 10 sub $0x10,%rsp
5b2e08: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax
5b2e0f: 00 00
5b2e11: 48 89 45 f8 mov %rax,-0x8(%rbp)
5b2e15: 31 c0 xor %eax,%eax
return bpf_map__next(prev, obj);
5b2e17: 48 8b 45 f8 mov -0x8(%rbp),%rax
5b2e1b: 64 48 2b 04 25 28 00 sub %fs:0x28,%rax
5b2e22: 00 00
5b2e24: 75 0f jne 5b2e35 <bpf_object__next_map+0x35>
}
5b2e26: c9 leave
5b2e27: 49 89 f8 mov %rdi,%r8
5b2e2a: 48 89 f7 mov %rsi,%rdi
return bpf_map__next(prev, obj);
5b2e2d: 4c 89 c6 mov %r8,%rsi
5b2e30: e9 cb b1 e5 ff jmp 40e000 <bpf_map__next@plt>
$
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.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/YozLKby7ITEtchC9@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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2022-05-26 11:02:02 -03:00 |