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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A5941C77B7A for ; Tue, 6 Jun 2023 04:48:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5h+NvYZ5N5fSaCZaiOcdkttJ4gc2igm0jSNepFq5mU4=; b=QiJoYFSuigCfdi XTnaNwYNBvsuxcC2ooq1e/4KKF3/BxVVFbI/th1u97q5IMlDR7oVCnXn+HjWpzTs5qsxpefvjHl4C as4wIli7tUypNx33K4cztM1+N5Ix38kikJAfAsVP8Tw7oewbvHXonbL7edrR+xVHNXO2SmZMo3bGM CkCt7yrCLHUWIENGuFQkq5Y5iPm8uTeiHzCbj0HBjgjfuIu6E9OIwd89EJ/Ppa62wyfoKlwKTubQI HegVLuGKJJ5TAtVIvV8XazHaalG/npX+kn61nzyf16cCNuSByESaxzTkd2eJ+CSe6Z8JJMtY05Ak3 Kclz/O3zxvERrAfrq+7Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q6Oba-000ASH-1q; Tue, 06 Jun 2023 04:47:38 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q6ObX-000ARG-27 for linux-arm-kernel@lists.infradead.org; Tue, 06 Jun 2023 04:47:37 +0000 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 899ABAB6; Mon, 5 Jun 2023 21:48:17 -0700 (PDT) Received: from [10.163.44.58] (unknown [10.163.44.58]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AD7093F587; Mon, 5 Jun 2023 21:47:24 -0700 (PDT) Message-ID: <1a8965ed-1210-2350-1c97-aebc27d005b7@arm.com> Date: Tue, 6 Jun 2023 10:17:20 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH V11 03/10] arm64/perf: Add branch stack support in struct arm_pmu Content-Language: en-US To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, Mark Brown , James Clark , Rob Herring , Marc Zyngier , Suzuki Poulose , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org References: <20230531040428.501523-1-anshuman.khandual@arm.com> <20230531040428.501523-4-anshuman.khandual@arm.com> From: Anshuman Khandual In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230605_214735_786181_40743276 X-CRM114-Status: GOOD ( 23.75 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 6/5/23 13:28, Mark Rutland wrote: > On Wed, May 31, 2023 at 09:34:21AM +0530, Anshuman Khandual wrote: >> This updates 'struct arm_pmu' for branch stack sampling support later. This >> adds a new 'features' element in the structure to track supported features, >> and another 'private' element to encapsulate implementation attributes on a >> given 'struct arm_pmu'. These updates here will help in tracking any branch >> stack sampling support, which is being added later. This also adds a helper >> arm_pmu_branch_stack_supported(). >> >> This also enables perf branch stack sampling event on all 'struct arm pmu', >> supporting the feature but after removing the current gate that blocks such >> events unconditionally in armpmu_event_init(). Instead a quick probe can be >> initiated via arm_pmu_branch_stack_supported() to ascertain the support. >> >> Cc: Catalin Marinas >> Cc: Will Deacon >> Cc: Mark Rutland >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> Tested-by: James Clark >> Signed-off-by: Anshuman Khandual >> --- >> drivers/perf/arm_pmu.c | 3 +-- >> include/linux/perf/arm_pmu.h | 12 +++++++++++- >> 2 files changed, 12 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c >> index aada47e3b126..d4a4f2bd89a5 100644 >> --- a/drivers/perf/arm_pmu.c >> +++ b/drivers/perf/arm_pmu.c >> @@ -510,8 +510,7 @@ 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)) >> + if (has_branch_stack(event) && !arm_pmu_branch_stack_supported(armpmu)) >> return -EOPNOTSUPP; >> >> return __hw_perf_event_init(event); >> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h >> index f7fbd162ca4c..0da745eaf426 100644 >> --- a/include/linux/perf/arm_pmu.h >> +++ b/include/linux/perf/arm_pmu.h >> @@ -102,7 +102,9 @@ struct arm_pmu { >> int (*map_event)(struct perf_event *event); >> void (*sched_task)(struct perf_event_pmu_context *pmu_ctx, bool sched_in); >> int num_events; >> - bool secure_access; /* 32-bit ARM only */ >> + unsigned int secure_access : 1, /* 32-bit ARM only */ >> + has_branch_stack: 1, /* 64-bit ARM only */ >> + reserved : 30; >> #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 >> DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); >> #define ARMV8_PMUV3_EXT_COMMON_EVENT_BASE 0x4000 >> @@ -118,8 +120,16 @@ struct arm_pmu { >> >> /* Only to be used by ACPI probing code */ >> unsigned long acpi_cpuid; >> + >> + /* Implementation specific attributes */ >> + void *private; >> }; >> >> +static inline bool arm_pmu_branch_stack_supported(struct arm_pmu *armpmu) >> +{ >> + return armpmu->has_branch_stack; >> +} > > Since this is a trivial test, and we already access the 'secure_access' field > directly, I'd prefer we removed this helper and directly accessesed > arm_pmu::has_branch_stack, e.g. with the logic in armpmu_event_init() being: > > if (has_branch_stack(event) && !armpmu->has_branch_stack) > return -EOPNOTSUPP; Sure, will drop the helper and change as suggested in all the call sites. > > With that: > > Acked-by: Mark Rutland > > Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel