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perf build: Stop using __weak bpf_object__next_program() to handle older libbpf versions

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By adding a feature test for bpf_object__next_program() 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_program.make.output
  test-libbpf-bpf_object__next_program.c: In function ‘main’:
  test-libbpf-bpf_object__next_program.c:6:9: error: implicit declaration of function ‘bpf_object__next_program’; did you mean ‘bpf_object__unpin_programs’? [-Werror=implicit-function-declaration]
      6 |         bpf_object__next_program(NULL /* obj */, NULL /* prev */);
        |         ^~~~~~~~~~~~~~~~~~~~~~~~
        |         bpf_object__unpin_programs
  cc1: all warnings being treated as errors
  $
  $ objdump -dS /tmp/build/perf/perf | grep '<bpf_object__next_program>:' -A20
  00000000005b2dc0 <bpf_object__next_program>:
  {
    5b2dc0:	55                   	push   %rbp
    5b2dc1:	48 89 e5             	mov    %rsp,%rbp
    5b2dc4:	48 83 ec 10          	sub    $0x10,%rsp
    5b2dc8:	64 48 8b 04 25 28 00 	mov    %fs:0x28,%rax
    5b2dcf:	00 00
    5b2dd1:	48 89 45 f8          	mov    %rax,-0x8(%rbp)
    5b2dd5:	31 c0                	xor    %eax,%eax
	  return bpf_program__next(prev, obj);
    5b2dd7:	48 8b 45 f8          	mov    -0x8(%rbp),%rax
    5b2ddb:	64 48 2b 04 25 28 00 	sub    %fs:0x28,%rax
    5b2de2:	00 00
    5b2de4:	75 0f                	jne    5b2df5 <bpf_object__next_program+0x35>
  }
    5b2de6:	c9                   	leave
    5b2de7:	49 89 f8             	mov    %rdi,%r8
    5b2dea:	48 89 f7             	mov    %rsi,%rdi
	  return bpf_program__next(prev, obj);
    5b2ded:	4c 89 c6             	mov    %r8,%rsi
    5b2df0:	e9 3b b4 e5 ff       	jmp    40e230 <bpf_program__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>
This commit is contained in:
Jiri Olsa 2022-05-24 13:09:42 +02:00 committed by Arnaldo Carvalho de Melo
parent 5c83eff381
commit 8916d72554
5 changed files with 21 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
tools/build/Makefile.feature
View File

@ -100,6 +100,7 @@ FEATURE_TESTS_EXTRA := \
libbpf \
libbpf-btf__load_from_kernel_by_id \
libbpf-bpf_prog_load \
libbpf-bpf_object__next_program \
libpfm4 \
libdebuginfod \
clang-bpf-co-re

4
tools/build/feature/Makefile
View File

@ -59,6 +59,7 @@ FILES= \
test-libbpf.bin \
test-libbpf-btf__load_from_kernel_by_id.bin \
test-libbpf-bpf_prog_load.bin \
test-libbpf-bpf_object__next_program.bin \
test-get_cpuid.bin \
test-sdt.bin \
test-cxx.bin \
@ -295,6 +296,9 @@ $(OUTPUT)test-libbpf-btf__load_from_kernel_by_id.bin:
$(OUTPUT)test-libbpf-bpf_prog_load.bin:
$(BUILD) -lbpf
$(OUTPUT)test-libbpf-bpf_object__next_program.bin:
$(BUILD) -lbpf
$(OUTPUT)test-sdt.bin:
$(BUILD)

8
tools/build/feature/test-libbpf-bpf_object__next_program.c Normal file
View File

@ -0,0 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
#include <bpf/libbpf.h>
int main(void)
{
bpf_object__next_program(NULL /* obj */, NULL /* prev */);
return 0;
}

5
tools/perf/Makefile.config
View File

@ -577,12 +577,17 @@ ifndef NO_LIBELF
ifeq ($(feature-libbpf-bpf_prog_load), 1)
CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD
endif
$(call feature_check,libbpf-bpf_object__next_program)
ifeq ($(feature-libbpf-bpf_object__next_program), 1)
CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
endif
else
dummy := $(error Error: No libbpf devel library found, please install libbpf-devel);
endif
else
CFLAGS += -DHAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD
CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
endif
endif

4
tools/perf/util/bpf-event.c
View File

@ -50,7 +50,8 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
}
#endif
struct bpf_program * __weak
#ifndef HAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
struct bpf_program *
bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev)
{
#pragma GCC diagnostic push
@ -58,6 +59,7 @@ bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev)
return bpf_program__next(prev, obj);
#pragma GCC diagnostic pop
}
#endif
struct bpf_map * __weak
bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev)