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 212ABC63684 for ; Wed, 26 Jan 2022 17:07:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243557AbiAZRH2 (ORCPT ); Wed, 26 Jan 2022 12:07:28 -0500 Received: from mail-oi1-f172.google.com ([209.85.167.172]:37677 "EHLO mail-oi1-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243359AbiAZRH0 (ORCPT ); Wed, 26 Jan 2022 12:07:26 -0500 Received: by mail-oi1-f172.google.com with SMTP id u129so813795oib.4; Wed, 26 Jan 2022 09:07:26 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=XnY1SI54q5HvUc3L+SPY6gdKVBD2B5KcgxIbNLuymQc=; b=EtAqh8OUOU+F6gq3+ZaafcOZpzlj9NKDfPYzdCwNnYvl4d0D7OaGcM10qW04gorc0y UV0elecKwob/zh503fLbJ7jRCdvD2hS5Z7lsi93fnZx+i+HUJuYNbzzoVEAApNrZiLqr lCsPUm4W/rnH55HeHekiY0a3pa2IwwR9jQds0JkIv64vFohpxKIDzdTTaljepeddTMFZ 1eXBgmknuCZatxn45bpo8ObPeVwDnJi56RgsBHYRW9gxStUD6+YZzWqE24/NTDtQNYzY zPjiLvHLYwNnnOIsHZ9ZePU1kgdl4G75FFkYVpowZZw74d0PT8dAW4H+oysKWNs199vY 4Plg== X-Gm-Message-State: AOAM531ApvEWPb2Ix0nqJtavt/n+TFQbOcez/lE9yW2uOZy8uYgi0IMO Ixxj38CBLY8EdsJdWJzq6w== X-Google-Smtp-Source: ABdhPJxQUgzqmtQRKb4Zwd3FAlDFBkluj9T157unv63xB3jC4dyW8GP67AmuT7J4/rhyBEr02/rERQ== X-Received: by 2002:a05:6808:152b:: with SMTP id u43mr4797879oiw.1.1643216846291; Wed, 26 Jan 2022 09:07:26 -0800 (PST) Received: from robh.at.kernel.org (66-90-148-213.dyn.grandenetworks.net. [66.90.148.213]) by smtp.gmail.com with ESMTPSA id s18sm489244oie.0.2022.01.26.09.07.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Jan 2022 09:07:25 -0800 (PST) Received: (nullmailer pid 978817 invoked by uid 1000); Wed, 26 Jan 2022 17:07:24 -0000 Date: Wed, 26 Jan 2022 11:07:24 -0600 From: Rob Herring To: Anshuman Khandual Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Mark Rutland , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org Subject: Re: [RFC V1 06/11] arm64/perf: Drive BRBE from perf event states Message-ID: References: <1642998653-21377-1-git-send-email-anshuman.khandual@arm.com> <1642998653-21377-7-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1642998653-21377-7-git-send-email-anshuman.khandual@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 24, 2022 at 10:00:48AM +0530, Anshuman Khandual wrote: > Branch stack sampling rides along the normal perf event and all the branch > records get captured during the PMU interrupt. This just changes perf event > handling on the arm64 platform to accommodate required BRBE operations that > will enable branch stack sampling support. > > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Arnaldo Carvalho de Melo > Cc: Mark Rutland > Cc: Will Deacon > Cc: Catalin Marinas > Cc: linux-perf-users@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-arm-kernel@lists.infradead.org > Signed-off-by: Anshuman Khandual > --- > arch/arm64/kernel/perf_event.c | 6 +++++ > drivers/perf/arm_pmu.c | 40 ++++++++++++++++++++++++++++++++++ > 2 files changed, 46 insertions(+) > > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c > index f6a47036b0b4..11c82c8f2eec 100644 > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -864,6 +864,12 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) > if (!armpmu_event_set_period(event)) > continue; > > + if (has_branch_stack(event)) { > + cpu_pmu->brbe_read(cpuc, event); Is has_branch_stack() guaranteed to be false on arm32? If not, this will be a NULL function ptr. To add to my other comments, this patch is where I would add brbe_read(), etc. to arm_pmu. Rob