From f1bdebbb67bd21d7c5dfc42f313f2f54002440b8 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 19 Oct 2022 08:44:17 -0400 Subject: perf bpf: Fix build with libbpf 0.7.0 by checking if bpf_program__set_insns() is available During the transition to libbpf 1.0 some functions that perf used were deprecated and finally removed from libbpf, so bpf_program__set_insns() was introduced for perf to continue to use its bpf loader. But when build with LIBBPF_DYNAMIC=1 we now need to check if that function is available so that perf can build with older libbpf versions, even if the end result is emitting a warning to the user that the use of the perf BPF loader requires a newer libbpf, since bpf_program__set_insns() touches libbpf objects internal state. This affects only 'perf trace' when using bpf C code or pre-compiled bytecode as an event. Noticed on RHEL9, that has libbpf 0.7.0, where bpf_program__set_insns() isn't available. Signed-off-by: Arnaldo Carvalho de Melo --- tools/build/Makefile.feature | 1 + tools/build/feature/Makefile | 4 ++++ .../build/feature/test-libbpf-bpf_program__set_insns.c | 8 ++++++++ tools/perf/Makefile.config | 5 +++++ tools/perf/util/bpf-loader.c | 18 ++++++++++++++++++ 5 files changed, 36 insertions(+) create mode 100644 tools/build/feature/test-libbpf-bpf_program__set_insns.c (limited to 'tools') diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature index 57619f240b56..38f8851bd7cb 100644 --- a/tools/build/Makefile.feature +++ b/tools/build/Makefile.feature @@ -103,6 +103,7 @@ FEATURE_TESTS_EXTRA := \ libbpf-bpf_prog_load \ libbpf-bpf_object__next_program \ libbpf-bpf_object__next_map \ + libbpf-bpf_program__set_insns \ libbpf-bpf_create_map \ libpfm4 \ libdebuginfod \ diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile index 04b07ff88234..690fe97be190 100644 --- a/tools/build/feature/Makefile +++ b/tools/build/feature/Makefile @@ -63,6 +63,7 @@ FILES= \ test-libbpf-bpf_map_create.bin \ test-libbpf-bpf_object__next_program.bin \ test-libbpf-bpf_object__next_map.bin \ + test-libbpf-bpf_program__set_insns.bin \ test-libbpf-btf__raw_data.bin \ test-get_cpuid.bin \ test-sdt.bin \ @@ -316,6 +317,9 @@ $(OUTPUT)test-libbpf-bpf_object__next_program.bin: $(OUTPUT)test-libbpf-bpf_object__next_map.bin: $(BUILD) -lbpf +$(OUTPUT)test-libbpf-bpf_program__set_insns.bin: + $(BUILD) -lbpf + $(OUTPUT)test-libbpf-btf__raw_data.bin: $(BUILD) -lbpf diff --git a/tools/build/feature/test-libbpf-bpf_program__set_insns.c b/tools/build/feature/test-libbpf-bpf_program__set_insns.c new file mode 100644 index 000000000000..f3b7f18c8f49 --- /dev/null +++ b/tools/build/feature/test-libbpf-bpf_program__set_insns.c @@ -0,0 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +int main(void) +{ + bpf_program__set_insns(NULL /* prog */, NULL /* new_insns */, 0 /* new_insn_cnt */); + return 0; +} diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config index 6fd4b1384b97..898226ea8cad 100644 --- a/tools/perf/Makefile.config +++ b/tools/perf/Makefile.config @@ -588,6 +588,10 @@ ifndef NO_LIBELF ifeq ($(feature-libbpf-bpf_object__next_map), 1) CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP endif + $(call feature_check,libbpf-bpf_program__set_insns) + ifeq ($(feature-libbpf-bpf_program__set_insns), 1) + CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS + endif $(call feature_check,libbpf-btf__raw_data) ifeq ($(feature-libbpf-btf__raw_data), 1) CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA @@ -604,6 +608,7 @@ ifndef NO_LIBELF CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP + CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA CFLAGS += -DHAVE_LIBBPF_BPF_MAP_CREATE endif diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index d657594894cf..f4adeccdbbcb 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -36,6 +36,24 @@ #include +#ifndef HAVE_LIBBPF_BPF_PROGRAM__SET_INSNS +int bpf_program__set_insns(struct bpf_program *prog __maybe_unused, + struct bpf_insn *new_insns __maybe_unused, size_t new_insn_cnt __maybe_unused) +{ + pr_err("%s: not support, update libbpf\n", __func__); + return -ENOTSUP; +} + +int libbpf_register_prog_handler(const char *sec __maybe_unused, + enum bpf_prog_type prog_type __maybe_unused, + enum bpf_attach_type exp_attach_type __maybe_unused, + const struct libbpf_prog_handler_opts *opts __maybe_unused) +{ + pr_err("%s: not support, update libbpf\n", __func__); + return -ENOTSUP; +} +#endif + /* temporarily disable libbpf deprecation warnings */ #pragma GCC diagnostic ignored "-Wdeprecated-declarations" -- cgit v1.2.3-59-g8ed1b