From nobody Fri Dec 19 21:10:51 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FEC6EDEC79 for ; Wed, 13 Sep 2023 15:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229658AbjIMPeh (ORCPT ); Wed, 13 Sep 2023 11:34:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229586AbjIMPef (ORCPT ); Wed, 13 Sep 2023 11:34:35 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E2A02E5; Wed, 13 Sep 2023 08:34:30 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D70191FB; Wed, 13 Sep 2023 08:35:07 -0700 (PDT) Received: from localhost.localdomain (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 1DBAF3F5A1; Wed, 13 Sep 2023 08:34:25 -0700 (PDT) From: James Clark To: linux-perf-users@vger.kernel.org, irogers@google.com, acme@kernel.org Cc: James Clark , John Garry , Will Deacon , Mike Leach , Leo Yan , Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Adrian Hunter , Kan Liang , Haixin Yu , Jing Zhang , Eduard Zingerman , Ravi Bangoria , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/3] perf pmu: Move pmu__find_core_pmu() to pmus.c Date: Wed, 13 Sep 2023 16:33:48 +0100 Message-Id: <20230913153355.138331-2-james.clark@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230913153355.138331-1-james.clark@arm.com> References: <20230913153355.138331-1-james.clark@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" pmu__find_core_pmu() more logically belongs in pmus.c because it iterates over all PMUs, so move it to pmus.c At the same time rename it to perf_pmus__find_core_pmu() to match the naming convention in this file. list_prepare_entry() can't be used in perf_pmus__scan_core() anymore now that it's called from the same compilation unit. This is with -O2 (specifically -O1 -ftree-vrp -finline-functions -finline-small-functions) which allow the bounds of the array access to be determined at compile time. list_prepare_entry() subtracts the offset of the 'list' member in struct perf_pmu from &core_pmus, which isn't a struct perf_pmu. The compiler sees that pmu results in &core_pmus - 8 and refuses to compile. At runtime this works because list_for_each_entry_continue() always adds the offset back again before dereferencing ->next, but it's technically undefined behavior. With -fsanitize=3Dundefined an additional warning is generated. Using list_first_entry_or_null() to get the first entry here avoids doing &core_pmus - 8 but has the same result and fixes both the compile warning and the undefined behavior warning. There are other uses of list_prepare_entry() in pmus.c, but the compiler doesn't seem to be able to see that they can also be called with &core_pmus, so I won't change any at this time. Signed-off-by: James Clark Reviewed-by: Ian Rogers Reviewed-by: John Garry --- tools/perf/arch/arm64/util/pmu.c | 6 +++--- tools/perf/tests/expr.c | 2 +- tools/perf/util/expr.c | 2 +- tools/perf/util/pmu.c | 17 ----------------- tools/perf/util/pmu.h | 2 +- tools/perf/util/pmus.c | 20 +++++++++++++++++++- 6 files changed, 25 insertions(+), 24 deletions(-) diff --git a/tools/perf/arch/arm64/util/pmu.c b/tools/perf/arch/arm64/util/= pmu.c index 615084eb88d8..3d9330feebd2 100644 --- a/tools/perf/arch/arm64/util/pmu.c +++ b/tools/perf/arch/arm64/util/pmu.c @@ -10,7 +10,7 @@ =20 const struct pmu_metrics_table *pmu_metrics_table__find(void) { - struct perf_pmu *pmu =3D pmu__find_core_pmu(); + struct perf_pmu *pmu =3D perf_pmus__find_core_pmu(); =20 if (pmu) return perf_pmu__find_metrics_table(pmu); @@ -20,7 +20,7 @@ const struct pmu_metrics_table *pmu_metrics_table__find(v= oid) =20 const struct pmu_events_table *pmu_events_table__find(void) { - struct perf_pmu *pmu =3D pmu__find_core_pmu(); + struct perf_pmu *pmu =3D perf_pmus__find_core_pmu(); =20 if (pmu) return perf_pmu__find_events_table(pmu); @@ -32,7 +32,7 @@ double perf_pmu__cpu_slots_per_cycle(void) { char path[PATH_MAX]; unsigned long long slots =3D 0; - struct perf_pmu *pmu =3D pmu__find_core_pmu(); + struct perf_pmu *pmu =3D perf_pmus__find_core_pmu(); =20 if (pmu) { perf_pmu__pathname_scnprintf(path, sizeof(path), diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c index 78544092ef0c..e3aa9d4fcf3a 100644 --- a/tools/perf/tests/expr.c +++ b/tools/perf/tests/expr.c @@ -76,7 +76,7 @@ static int test__expr(struct test_suite *t __maybe_unused= , int subtest __maybe_u struct expr_parse_ctx *ctx; bool is_intel =3D false; char strcmp_cpuid_buf[256]; - struct perf_pmu *pmu =3D pmu__find_core_pmu(); + struct perf_pmu *pmu =3D perf_pmus__find_core_pmu(); char *cpuid =3D perf_pmu__getcpuid(pmu); char *escaped_cpuid1, *escaped_cpuid2; =20 diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c index 4488f306de78..7be23b3ac082 100644 --- a/tools/perf/util/expr.c +++ b/tools/perf/util/expr.c @@ -509,7 +509,7 @@ double expr__strcmp_cpuid_str(const struct expr_parse_c= tx *ctx __maybe_unused, bool compute_ids __maybe_unused, const char *test_id) { double ret; - struct perf_pmu *pmu =3D pmu__find_core_pmu(); + struct perf_pmu *pmu =3D perf_pmus__find_core_pmu(); char *cpuid =3D perf_pmu__getcpuid(pmu); =20 if (!cpuid) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index e2159854ab26..f50a5636633f 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -2050,20 +2050,3 @@ void perf_pmu__delete(struct perf_pmu *pmu) zfree(&pmu->id); free(pmu); } - -struct perf_pmu *pmu__find_core_pmu(void) -{ - struct perf_pmu *pmu =3D NULL; - - while ((pmu =3D perf_pmus__scan_core(pmu))) { - /* - * The cpumap should cover all CPUs. Otherwise, some CPUs may - * not support some events or have different event IDs. - */ - if (RC_CHK_ACCESS(pmu->cpus)->nr !=3D cpu__max_cpu().cpu) - return NULL; - - return pmu; - } - return NULL; -} diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index bd5d804a6736..d7b46085642d 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -264,6 +264,6 @@ int perf_pmu__pathname_fd(int dirfd, const char *pmu_na= me, const char *filename, struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const= char *lookup_name); struct perf_pmu *perf_pmu__create_placeholder_core_pmu(struct list_head *c= ore_pmus); void perf_pmu__delete(struct perf_pmu *pmu); -struct perf_pmu *pmu__find_core_pmu(void); +struct perf_pmu *perf_pmus__find_core_pmu(void); =20 #endif /* __PMU_H */ diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c index 6631367c756f..cec869cbe163 100644 --- a/tools/perf/util/pmus.c +++ b/tools/perf/util/pmus.c @@ -10,6 +10,7 @@ #include #include #include +#include "cpumap.h" #include "debug.h" #include "evsel.h" #include "pmus.h" @@ -268,7 +269,7 @@ struct perf_pmu *perf_pmus__scan_core(struct perf_pmu *= pmu) { if (!pmu) { pmu_read_sysfs(/*core_only=3D*/true); - pmu =3D list_prepare_entry(pmu, &core_pmus, list); + return list_first_entry_or_null(&core_pmus, typeof(*pmu), list); } list_for_each_entry_continue(pmu, &core_pmus, list) return pmu; @@ -592,3 +593,20 @@ struct perf_pmu *evsel__find_pmu(const struct evsel *e= vsel) } return pmu; } + +struct perf_pmu *perf_pmus__find_core_pmu(void) +{ + struct perf_pmu *pmu =3D NULL; + + while ((pmu =3D perf_pmus__scan_core(pmu))) { + /* + * The cpumap should cover all CPUs. Otherwise, some CPUs may + * not support some events or have different event IDs. + */ + if (RC_CHK_ACCESS(pmu->cpus)->nr !=3D cpu__max_cpu().cpu) + return NULL; + + return pmu; + } + return NULL; +} --=20 2.34.1