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 X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D3FFC33CB1 for ; Fri, 17 Jan 2020 14:01:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 608772082F for ; Fri, 17 Jan 2020 14:01:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Etpm59pt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727580AbgAQOBz (ORCPT ); Fri, 17 Jan 2020 09:01:55 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:56268 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726587AbgAQOBz (ORCPT ); Fri, 17 Jan 2020 09:01:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=02vkEi6lxtA4lK33CdPk2WH+RGmnoTDnMl1bMs6Ix1Q=; b=Etpm59ptObPl8hzigJ5gTmz4i N1k1IkhLmFxME0A420uBwmIflzr6GqaIIQmyBceL2+f+HwUYZCZ9l0OW5hnzkWc2fuYH+3noLxILV PrO1zKzaLvU8YcjLeRWatAvlIIkO/zGZmJ2SfZKGb2BB8zTTndZDCYZiKaiDwN1CwfQbY6DuoR4bP Cq6i4wBDhW5IgHYTB4dZ6AUF/0NbY7d7yiKjRwUSeBcplkKiGK6/d8cyxcDqfw6LJs/IiYI2AARZB 3iywZx0NyV28zDaT6jJGXMfV7jhbrW2bnyUTIdenvKZKb501xgPQ7m9o3YmWliy+oug0ajwPVaLgN KU1nqfBPg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1isSC2-0008MG-2C; Fri, 17 Jan 2020 14:01:46 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 66B1E300F4B; Fri, 17 Jan 2020 15:00:06 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 948602020D8FC; Fri, 17 Jan 2020 15:01:43 +0100 (CET) Date: Fri, 17 Jan 2020 15:01:43 +0100 From: Peter Zijlstra To: Will Deacon Cc: James Clark , linux-arm-kernel@lists.infradead.org, nd@arm.com, Mark Rutland , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Tan Xiaojun , Al Grant , Namhyung Kim , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] Return EINVAL when precise_ip perf events are requested on Arm Message-ID: <20200117140143.GD14879@hirez.programming.kicks-ass.net> References: <20200115105855.13395-1-james.clark@arm.com> <20200115105855.13395-2-james.clark@arm.com> <20200117123920.GB8199@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200117123920.GB8199@willie-the-truck> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 17, 2020 at 12:39:21PM +0000, Will Deacon wrote: > Perhaps a better way would be to expose something under sysfs, a bit like > the caps directory for the SPE PMU, which identifies the fields of the attr > structure that the driver does not ignore. I think doing this as an Arm-PMU > specific thing initially would be fine, but it would be even better to have > something where a driver can tell perf core about the parts it responds to > and have this stuff populated automatically. The current design makes it > inevitable that PMU drivers will have issues like the one you point out in > the cover letter. > > Thoughts? We have PERF_PMU_CAP_ flags we could extend to that purpose.