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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 76E70C46460 for ; Wed, 15 Aug 2018 09:39:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26443216C1 for ; Wed, 15 Aug 2018 09:39:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 26443216C1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728993AbeHOMad (ORCPT ); Wed, 15 Aug 2018 08:30:33 -0400 Received: from foss.arm.com ([217.140.101.70]:53170 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728668AbeHOMad (ORCPT ); Wed, 15 Aug 2018 08:30:33 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D481E18A; Wed, 15 Aug 2018 02:39:06 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A57323F5BD; Wed, 15 Aug 2018 02:39:06 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 8C7571AE0DBE; Wed, 15 Aug 2018 10:39:13 +0100 (BST) Date: Wed, 15 Aug 2018 10:39:13 +0100 From: Will Deacon To: Mathieu Poirier Cc: Kim Phillips , Peter Zijlstra , Arnaldo Carvalho de Melo , Ingo Molnar , Thomas Gleixner , Alexander Shishkin , schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, Mark Rutland , Jiri Olsa , Namhyung Kim , Adrian Hunter , ast@kernel.org, Greg KH , "H. Peter Anvin" , suzuki.poulosi@arm.com, linux-s390@vger.kernel.org, Linux Kernel Mailing List , linux-arm-kernel Subject: Re: [PATCH v3 0/7] perf: Add ioctl for PMU driver configuration Message-ID: <20180815093912.GE2427@arm.com> References: <1531950487-24554-1-git-send-email-mathieu.poirier@linaro.org> <20180813124642.3d49c082a95fc294d926016e@arm.com> <20180814120910.ed225bbc462c58b09e5d68de@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 14, 2018 at 01:42:27PM -0600, Mathieu Poirier wrote: > On Tue, 14 Aug 2018 at 11:09, Kim Phillips wrote: > > The other thing that's going on here is that I'm becoming numb to the > > loathsome "failed to mmap with 12 (Cannot allocate memory)" being > > returned no matter what the error is/was. E.g., an error that would > > indicate a sense of non-implementation would be much better > > appreciated than presumably what the above is doing, i.e., returning > > -ENOMEM. That, backed up with specific details in the form of human > > readable text in dmesg would be *most* welcome. > > As part of the refactoring of the code to support CPU-wide scenarios I > intend to emit better diagnostic messages from the driver. Modifying > rb_alloc_aux() to propagate the error message generated by the > architecture specific PMUs doesn't look hard either and I _may_ get to > it as part of this work. For the record, I will continue to oppose PMU drivers that dump diagnostics about user-controlled input into dmesg, but the coresight drivers are yours so it's up to you and I won't get in the way! Will