From df76e0038370d364d4b2154fa7ddbbccc29f629f Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 26 May 2022 11:48:58 -0300 Subject: perf build: Stop using __weak bpf_map_create() 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_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 babf0bb978e3c9fc (torvalds/master) Merge tag 'xfs-5.19-for-linus' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux e375780b631a5fc2 Merge tag 'fsnotify_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 8b728edc5be16179 Merge tag 'fs_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 3f306ea2e18568f6 Merge tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping fbe86daca0ba878b Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi $ Coping with: $ git log --oneline -2 d16495a982324f75 d16495a982324f75 libbpf: remove bpf_create_map*() APIs e2371b1632b1c61c 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 ':' -A20 000000000058b290 : { 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 } 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 Cc: Heiko Carstens Cc: Ian Rogers Cc: Ilya Leoshkevich Cc: Jiri Olsa Cc: Song Liu Cc: Sumanth Korikkar Cc: Sven Schnelle Cc: Thomas Richter Cc: Vasily Gorbik Link: http://lore.kernel.org/linux-perf-users/Yo+XvQNKL4K5khl2@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/build/feature/Makefile | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'tools/build/feature/Makefile') diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile index 5b31a6d063d7..7c2a17e23c30 100644 --- a/tools/build/feature/Makefile +++ b/tools/build/feature/Makefile @@ -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_map_create.bin \ test-libbpf-bpf_object__next_program.bin \ test-libbpf-bpf_object__next_map.bin \ test-libbpf-btf__raw_data.bin \ @@ -298,6 +299,9 @@ $(OUTPUT)test-libbpf-btf__load_from_kernel_by_id.bin: $(OUTPUT)test-libbpf-bpf_prog_load.bin: $(BUILD) -lbpf +$(OUTPUT)test-libbpf-bpf_map_create.bin: + $(BUILD) -lbpf + $(OUTPUT)test-libbpf-bpf_object__next_program.bin: $(BUILD) -lbpf -- cgit v1.2.3-59-g8ed1b