From mboxrd@z Thu Jan 1 00:00:00 1970 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 71A4ECCA47C for ; Mon, 13 Jun 2022 10:03:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232008AbiFMKDE (ORCPT ); Mon, 13 Jun 2022 06:03:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241453AbiFMKCc (ORCPT ); Mon, 13 Jun 2022 06:02:32 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6628226CF; Mon, 13 Jun 2022 03:02:29 -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 AE1C91042; Mon, 13 Jun 2022 03:02:29 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.38.134]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 421013F66F; Mon, 13 Jun 2022 03:02:22 -0700 (PDT) From: Anshuman Khandual To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, peterz@infradead.org, acme@kernel.org, mark.rutland@arm.com, will@kernel.org Cc: Anshuman Khandual , Catalin Marinas , James Clark , Rob Herring , Marc Zyngier , Ingo Molnar , linux-perf-users@vger.kernel.org Subject: [PATCH 8/8] arm64/perf: Enable branch stack sampling Date: Mon, 13 Jun 2022 15:31:19 +0530 Message-Id: <20220613100119.684673-9-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220613100119.684673-1-anshuman.khandual@arm.com> References: <20220613100119.684673-1-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org Now that all the required pieces are already in place, just enable the perf branch stack sampling support on arm64 platform, by removing the gate which blocks it in armpmu_event_init(). Cc: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Anshuman Khandual --- drivers/perf/arm_pmu.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 52a903d26702..efbc6db42b35 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -537,9 +537,35 @@ static int armpmu_event_init(struct perf_event *event) !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus)) return -ENOENT; - /* does not support taken branch sampling */ - if (has_branch_stack(event)) - return -EOPNOTSUPP; + if (has_branch_stack(event)) { + /* + * BRBE support is absent. Select CONFIG_ARM_BRBE_PMU + * in the config, before branch stack sampling events + * can be requested. + */ + if (!IS_ENABLED(CONFIG_ARM_BRBE_PMU)) { + pr_warn_once("BRBE is disabled, select CONFIG_ARM_BRBE_PMU\n"); + return -EOPNOTSUPP; + } + + if (event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_KERNEL) { + if (!perfmon_capable()) { + pr_warn_once("does not have permission for kernel branch filter\n"); + return -EPERM; + } + } + + /* + * Branch stack sampling event can not be supported in + * case either the required driver itself is absent or + * BRBE buffer, is not supported. Besides checking for + * the callback prevents a crash in case it's absent. + */ + if (!armpmu->brbe_supported || !armpmu->brbe_supported(event)) { + pr_warn_once("BRBE is not supported\n"); + return -EOPNOTSUPP; + } + } if (armpmu->map_event(event) == -ENOENT) return -ENOENT; -- 2.25.1