From 739c9180cfa487cc92e2721e224564e4672c578e Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 24 May 2022 13:13:17 +0200 Subject: perf build: Stop using __weak bpf_object__next_map() to handle older libbpf versions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 ':' -A20 00000000005b2e00 : { 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 } 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 $ Signed-off-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Heiko Carstens Cc: Ian Rogers Cc: Ilya Leoshkevich Cc: Sumanth Korikkar Cc: Sven Schnelle Cc: Thomas Richter Cc: Vasily Gorbik Link: http://lore.kernel.org/linux-perf-users/YozLKby7ITEtchC9@krava Signed-off-by: Arnaldo Carvalho de Melo --- tools/build/Makefile.feature | 1 + tools/build/feature/Makefile | 4 ++++ tools/build/feature/test-libbpf-bpf_object__next_map.c | 8 ++++++++ 3 files changed, 13 insertions(+) create mode 100644 tools/build/feature/test-libbpf-bpf_object__next_map.c (limited to 'tools/build') diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature index 64f8cfa6c9af..34cf2bff72ca 100644 --- a/tools/build/Makefile.feature +++ b/tools/build/Makefile.feature @@ -101,6 +101,7 @@ FEATURE_TESTS_EXTRA := \ libbpf-btf__load_from_kernel_by_id \ libbpf-bpf_prog_load \ libbpf-bpf_object__next_program \ + libbpf-bpf_object__next_map \ libpfm4 \ libdebuginfod \ clang-bpf-co-re diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile index 6eb829704cb9..aecb6a28a770 100644 --- a/tools/build/feature/Makefile +++ b/tools/build/feature/Makefile @@ -60,6 +60,7 @@ FILES= \ test-libbpf-btf__load_from_kernel_by_id.bin \ test-libbpf-bpf_prog_load.bin \ test-libbpf-bpf_object__next_program.bin \ + test-libbpf-bpf_object__next_map.bin \ test-get_cpuid.bin \ test-sdt.bin \ test-cxx.bin \ @@ -299,6 +300,9 @@ $(OUTPUT)test-libbpf-bpf_prog_load.bin: $(OUTPUT)test-libbpf-bpf_object__next_program.bin: $(BUILD) -lbpf +$(OUTPUT)test-libbpf-bpf_object__next_map.bin: + $(BUILD) -lbpf + $(OUTPUT)test-sdt.bin: $(BUILD) diff --git a/tools/build/feature/test-libbpf-bpf_object__next_map.c b/tools/build/feature/test-libbpf-bpf_object__next_map.c new file mode 100644 index 000000000000..64adb519e97e --- /dev/null +++ b/tools/build/feature/test-libbpf-bpf_object__next_map.c @@ -0,0 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +int main(void) +{ + bpf_object__next_map(NULL /* obj */, NULL /* prev */); + return 0; +} -- cgit v1.2.3