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AJvYcCUMd6oU1+HV0JsMKpuZKD00DOdCm1SoDADF2GIBeJUSn9Bo6RXVNXYDQwyAhowtoMSqv2CoKNT3gE+s3x0=@vger.kernel.org X-Gm-Message-State: AOJu0YwsLxH3IpA5h0Kpo+L1QUIQkAh3B3u7yKub6bEkVAUqAjYugwbE cNTQdXkDBF3LU32i5mFQniJwoieqsCvi7sl7wPz8V1urr4qSI39epSKfJDUSlC6t15LrS7bqgGs +C0dNrvZU1Hq9eCatQQbxZA== X-Google-Smtp-Source: AGHT+IFkwzICCuJKoG3Txs4Pq6B8e3LNe8LcJQkOsHb3DYNAAlEc1BVX4L6i630fVFk+wQLTy/GH043sJlsKauzy X-Received: from pfbfc3.prod.google.com ([2002:a05:6a00:2e03:b0:747:bd3b:4b63]) (user=blakejones job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:549d:b0:1f5:769a:a4be with SMTP id adf61e73a8af0-21ee263f9b4mr1776658637.36.1749166787399; Thu, 05 Jun 2025 16:39:47 -0700 (PDT) Date: Thu, 5 Jun 2025 16:39:31 -0700 In-Reply-To: <20250605233934.1881839-1-blakejones@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250605233934.1881839-1-blakejones@google.com> X-Mailer: git-send-email 2.50.0.rc0.604.gd4ff7b7c86-goog Message-ID: <20250605233934.1881839-2-blakejones@google.com> Subject: [PATCH v2 1/4] perf: detect support for libbpf's emit_strings option From: Blake Jones To: Arnaldo Carvalho de Melo , Namhyung Kim , Ian Rogers , Jiri Olsa , Peter Zijlstra , Ingo Molnar Cc: Mark Rutland , Alexander Shishkin , Adrian Hunter , Kan Liang , Steven Rostedt , Tomas Glozar , James Clark , Leo Yan , Guilherme Amadio , Yang Jihong , Charlie Jenkins , Chun-Tse Shao , Aditya Gupta , Athira Rajeev , Zhongqiu Han , Andi Kleen , Dmitry Vyukov , Yujie Liu , Graham Woodward , Yicong Yang , Ben Gainey , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, Blake Jones Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This creates a config option that detects libbpf's ability to display character arrays as strings, which was just added to the BPF tree (https://git.kernel.org/bpf/bpf-next/c/87c9c79a02b4). To test this change, I built perf (from later in this patch set) with: - static libbpf (default, using source from kernel tree) - dynamic libbpf (LIBBPF_DYNAMIC=3D1 LIBBPF_INCLUDE=3D/usr/local/include) For both the static and dynamic versions, I used headers with and without the ".emit_strings" option. I verified that of the four resulting binaries, the two with ".emit_strings" would successfully record BPF_METADATA events, and the two without wouldn't. All four binaries would successfully display BPF_METADATA events, because the relevant bit of libbpf code is only used during "perf record". Signed-off-by: Blake Jones --- tools/build/Makefile.feature | 1 + tools/build/feature/Makefile | 4 ++++ tools/build/feature/test-libbpf-strings.c | 10 ++++++++++ tools/perf/Documentation/perf-check.txt | 1 + tools/perf/Makefile.config | 12 ++++++++++++ tools/perf/builtin-check.c | 1 + 6 files changed, 29 insertions(+) create mode 100644 tools/build/feature/test-libbpf-strings.c diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature index 57bd995ce6af..541ea3cc53e9 100644 --- a/tools/build/Makefile.feature +++ b/tools/build/Makefile.feature @@ -126,6 +126,7 @@ FEATURE_TESTS_EXTRA :=3D \ llvm \ clang \ libbpf \ + libbpf-strings \ libbpf-btf__load_from_kernel_by_id \ libbpf-bpf_prog_load \ libbpf-bpf_object__next_program \ diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile index b8b5fb183dd4..327bb501fd2b 100644 --- a/tools/build/feature/Makefile +++ b/tools/build/feature/Makefile @@ -59,6 +59,7 @@ FILES=3D \ test-lzma.bin \ test-bpf.bin \ test-libbpf.bin \ + test-libbpf-strings.bin \ test-get_cpuid.bin \ test-sdt.bin \ test-cxx.bin \ @@ -360,6 +361,9 @@ $(OUTPUT)test-libbpf-bpf_program__set_insns.bin: $(OUTPUT)test-libbpf-btf__raw_data.bin: $(BUILD) -lbpf =20 +$(OUTPUT)test-libbpf-strings.bin: + $(BUILD) + $(OUTPUT)test-sdt.bin: $(BUILD) =20 diff --git a/tools/build/feature/test-libbpf-strings.c b/tools/build/featur= e/test-libbpf-strings.c new file mode 100644 index 000000000000..83e6c45f5c85 --- /dev/null +++ b/tools/build/feature/test-libbpf-strings.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +int main(void) +{ + struct btf_dump_type_data_opts opts; + + opts.emit_strings =3D 0; + return opts.emit_strings; +} diff --git a/tools/perf/Documentation/perf-check.txt b/tools/perf/Documenta= tion/perf-check.txt index a764a4629220..799982d8d868 100644 --- a/tools/perf/Documentation/perf-check.txt +++ b/tools/perf/Documentation/perf-check.txt @@ -52,6 +52,7 @@ feature:: dwarf-unwind / HAVE_DWARF_UNWIND_SUPPORT auxtrace / HAVE_AUXTRACE_SUPPORT libbfd / HAVE_LIBBFD_SUPPORT + libbpf-strings / HAVE_LIBBPF_STRINGS_SUPPORT libcapstone / HAVE_LIBCAPSTONE_SUPPORT libcrypto / HAVE_LIBCRYPTO_SUPPORT libdw-dwarf-unwind / HAVE_LIBDW_SUPPORT diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config index d1ea7bf44964..647ade45e4e5 100644 --- a/tools/perf/Makefile.config +++ b/tools/perf/Makefile.config @@ -595,8 +595,20 @@ ifndef NO_LIBELF LIBBPF_STATIC :=3D 1 $(call detected,CONFIG_LIBBPF) CFLAGS +=3D -DHAVE_LIBBPF_SUPPORT + ifneq ($(OUTPUT),) + LIBBPF_INCLUDE =3D $(abspath $(OUTPUT))/libbpf/include + else + LIBBPF_INCLUDE =3D $(CURDIR)/libbpf/include + endif endif endif + + FEATURE_CHECK_CFLAGS-libbpf-strings=3D"-I$(LIBBPF_INCLUDE)" + $(call feature_check,libbpf-strings) + ifeq ($(feature-libbpf-strings), 1) + $(call detected,CONFIG_LIBBPF_STRINGS) + CFLAGS +=3D -DHAVE_LIBBPF_STRINGS_SUPPORT + endif endif endif # NO_LIBBPF endif # NO_LIBELF diff --git a/tools/perf/builtin-check.c b/tools/perf/builtin-check.c index 9a509cb3bb9a..f4827f0ddb47 100644 --- a/tools/perf/builtin-check.c +++ b/tools/perf/builtin-check.c @@ -43,6 +43,7 @@ struct feature_status supported_features[] =3D { FEATURE_STATUS("dwarf-unwind", HAVE_DWARF_UNWIND_SUPPORT), FEATURE_STATUS("auxtrace", HAVE_AUXTRACE_SUPPORT), FEATURE_STATUS_TIP("libbfd", HAVE_LIBBFD_SUPPORT, "Deprecated, license in= compatibility, use BUILD_NONDISTRO=3D1 and install binutils-dev[el]"), + FEATURE_STATUS("libbpf-strings", HAVE_LIBBPF_STRINGS_SUPPORT), FEATURE_STATUS("libcapstone", HAVE_LIBCAPSTONE_SUPPORT), FEATURE_STATUS("libcrypto", HAVE_LIBCRYPTO_SUPPORT), FEATURE_STATUS("libdw-dwarf-unwind", HAVE_LIBDW_SUPPORT), --=20 2.50.0.rc0.604.gd4ff7b7c86-goog