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 93463C4332F for ; Tue, 12 Apr 2022 12:34:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235678AbiDLMhI (ORCPT ); Tue, 12 Apr 2022 08:37:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351898AbiDLMgO (ORCPT ); Tue, 12 Apr 2022 08:36:14 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 48C2B13F81; Tue, 12 Apr 2022 04:55:42 -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 133121424; Tue, 12 Apr 2022 04:55:42 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.38.213]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B9AC33F70D; Tue, 12 Apr 2022 04:55:35 -0700 (PDT) From: Anshuman Khandual To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , Mark Rutland , James Clark , Rob Herring , Marc Zyngier , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org Subject: [RFC V2 8/8] arm64/perf: Enable branch stack sampling Date: Tue, 12 Apr 2022 17:24:55 +0530 Message-Id: <20220412115455.293119-9-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220412115455.293119-1-anshuman.khandual@arm.com> References: <20220412115455.293119-1-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 ab187a3bcdab..8b08811f662a 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -539,9 +539,35 @@ 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