From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758902AbdEVMc5 (ORCPT ); Mon, 22 May 2017 08:32:57 -0400 Received: from foss.arm.com ([217.140.101.70]:36364 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752479AbdEVMcy (ORCPT ); Mon, 22 May 2017 08:32:54 -0400 Date: Mon, 22 May 2017 07:32:49 -0500 From: Kim Phillips To: Will Deacon , , , , , , , , Cc: , , , Subject: Re: [PATCH v3 4/5] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Message-Id: <20170522073249.d95a6d7050d24e99261ceae6@arm.com> In-Reply-To: <1495128273-13941-5-git-send-email-will.deacon@arm.com> References: <1495128273-13941-1-git-send-email-will.deacon@arm.com> <1495128273-13941-5-git-send-email-will.deacon@arm.com> Organization: ARM X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 18 May 2017 18:24:32 +0100 Will Deacon wrote: > +/* Perf callbacks */ > +static int arm_spe_pmu_event_init(struct perf_event *event) > +{ > + u64 reg; > + struct perf_event_attr *attr = &event->attr; > + struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); > + > + /* This is, of course, deeply driver-specific */ > + if (attr->type != event->pmu->type) > + return -ENOENT; > + > + if (event->cpu >= 0 && > + !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus)) > + return -ENOENT; > + > + if (arm_spe_event_to_pmsevfr(event) & PMSEVFR_EL1_RES0) > + return -EOPNOTSUPP; > + > + if (event->hw.sample_period < spe_pmu->min_period || > + event->hw.sample_period & PMSIRR_EL1_IVAL_MASK) > + return -EOPNOTSUPP; > + > + if (attr->exclude_idle) > + return -EOPNOTSUPP; > + > + /* > + * Feedback-directed frequency throttling doesn't work when we > + * have a buffer of samples. We'd need to manually count the > + * samples in the buffer when it fills up and adjust the event > + * count to reflect that. Instead, force the user to specify a > + * sample period instead. > + */ > + if (attr->freq) > + return -EINVAL; > + > + reg = arm_spe_event_to_pmsfcr(event); > + if ((reg & BIT(PMSFCR_EL1_FE_SHIFT)) && > + !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT)) > + return -EOPNOTSUPP; > + > + if ((reg & BIT(PMSFCR_EL1_FT_SHIFT)) && > + !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP)) > + return -EOPNOTSUPP; > + > + if ((reg & BIT(PMSFCR_EL1_FL_SHIFT)) && > + !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT)) > + return -EOPNOTSUPP; I've consistently brought up lack of proper user error messaging in all previous submissions of this driver: Jan. 10 2017 (first RFC): https://www.spinics.net/lists/arm-kernel/msg553322.html Jan. 13 (second RFC): https://patchwork.kernel.org/patch/9515967/ [I just went ahead and re-read https://lkml.org/lkml/2015/8/26/661 and still think it's not a reason to not do this] 30 Jan 2017 (first PATCH series): https://www.spinics.net/lists/arm-kernel/msg559232.html 6 apr 2017 (PATCH v2 series): https://lkml.org/lkml/2017/4/6/790 AFAICT, my comments hold, yet the driver still gets resubmitted without them being addressed. How do we get out of this loop? Kim