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 B49F3C6FA82 for ; Tue, 13 Sep 2022 11:38:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231602AbiIMLik (ORCPT ); Tue, 13 Sep 2022 07:38:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229782AbiIMLii (ORCPT ); Tue, 13 Sep 2022 07:38:38 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C4E082EF24; Tue, 13 Sep 2022 04:38:37 -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 EAAE81063; Tue, 13 Sep 2022 04:38:43 -0700 (PDT) Received: from [10.163.58.193] (unknown [10.163.58.193]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 731DB3F71A; Tue, 13 Sep 2022 04:38:33 -0700 (PDT) Message-ID: Date: Tue, 13 Sep 2022 17:08:30 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH V2 6/7] arm64/perf: Add BRBE driver Content-Language: en-US To: James Clark Cc: Rob Herring , Marc Zyngier , Ingo Molnar , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, peterz@infradead.org, acme@kernel.org, mark.rutland@arm.com, will@kernel.org, catalin.marinas@arm.com, German Gomez References: <20220908051046.465307-1-anshuman.khandual@arm.com> <20220908051046.465307-7-anshuman.khandual@arm.com> <740298c9-0cae-251d-97b4-d2724399ba40@arm.com> From: Anshuman Khandual In-Reply-To: <740298c9-0cae-251d-97b4-d2724399ba40@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/13/22 16:09, James Clark wrote: > > > On 08/09/2022 06:10, Anshuman Khandual wrote: >> This adds a BRBE driver which implements all the required helper functions >> for struct arm_pmu. Following functions are defined by this driver which >> will configure, enable, capture, reset and disable BRBE buffer HW as and >> when requested via perf branch stack sampling framework. >> >> - arm64_pmu_brbe_filter() >> - arm64_pmu_brbe_enable() >> - arm64_pmu_brbe_disable() >> - arm64_pmu_brbe_read() >> - arm64_pmu_brbe_probe() >> - arm64_pmu_brbe_reset() >> - arm64_pmu_brbe_supported() >> >> Cc: Peter Zijlstra >> Cc: Ingo Molnar >> Cc: Arnaldo Carvalho de Melo >> Cc: Mark Rutland >> Cc: Will Deacon >> Cc: Catalin Marinas >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-perf-users@vger.kernel.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual >> --- >> arch/arm64/kernel/perf_event.c | 8 +- >> drivers/perf/Kconfig | 11 + >> drivers/perf/Makefile | 1 + >> drivers/perf/arm_pmu_brbe.c | 448 +++++++++++++++++++++++++++++++++ >> drivers/perf/arm_pmu_brbe.h | 259 +++++++++++++++++++ >> include/linux/perf/arm_pmu.h | 20 ++ >> 6 files changed, 746 insertions(+), 1 deletion(-) >> create mode 100644 drivers/perf/arm_pmu_brbe.c >> create mode 100644 drivers/perf/arm_pmu_brbe.h >> > [...] >> + >> +static int brbe_fetch_perf_priv(u64 brbinf) >> +{ >> + int brbe_el = brbe_fetch_el(brbinf); >> + >> + switch (brbe_el) { >> + case BRBINF_EL_EL0: >> + return PERF_BR_PRIV_USER; >> + case BRBINF_EL_EL1: >> + return PERF_BR_PRIV_KERNEL; >> + case BRBINF_EL_EL2: >> + if (is_kernel_in_hyp_mode()) >> + return PERF_BR_PRIV_KERNEL; >> + return PERF_BR_PRIV_HV; >> + default: >> + pr_warn("unknown branch privilege captured\n"); >> + return -1; > > On V1 you said that you would change this to PERF_BR_PRIV_UNKNOWN, looks > like that was dropped. Unless it didn't work out? Seems like it just got dropped unintentionally. Yes, PERF_BR_PRIV_UNKNOWN can be returned here instead of "-1", similar to brbe_fetch_perf_type() which returns PERF_BR_UNKNOWN.