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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 06B20C433E0 for ; Mon, 1 Feb 2021 12:09:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE24E64E2A for ; Mon, 1 Feb 2021 12:09:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231126AbhBAMJ2 (ORCPT ); Mon, 1 Feb 2021 07:09:28 -0500 Received: from foss.arm.com ([217.140.110.172]:58130 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229554AbhBAMJY (ORCPT ); Mon, 1 Feb 2021 07:09:24 -0500 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 2FF1DED1; Mon, 1 Feb 2021 04:08:38 -0800 (PST) Received: from [10.57.35.163] (unknown [10.57.35.163]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 54B853F718; Mon, 1 Feb 2021 04:08:36 -0800 (PST) Subject: Re: [PATCH v4 1/2] perf/smmuv3: Don't reserve the PMCG register spaces To: Zhen Lei , Will Deacon , Mark Rutland , Joerg Roedel , linux-arm-kernel , iommu , linux-kernel Cc: Jean-Philippe Brucker , Shameer Kolothum References: <20210130071414.1575-1-thunder.leizhen@huawei.com> <20210130071414.1575-2-thunder.leizhen@huawei.com> From: Robin Murphy Message-ID: <9904b39d-f328-14d6-b5d8-8b9e8a1437b6@arm.com> Date: Mon, 1 Feb 2021 12:08:35 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210130071414.1575-2-thunder.leizhen@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-01-30 07:14, Zhen Lei wrote: > According to the SMMUv3 specification: > Each PMCG counter group is represented by one 4KB page (Page 0) with one > optional additional 4KB page (Page 1), both of which are at IMPLEMENTATION > DEFINED base addresses. > > This means that the PMCG register spaces may be within the 64KB pages of > the SMMUv3 register space. When both the SMMU and PMCG drivers reserve > their own resources, a resource conflict occurs. > > To avoid this conflict, don't reserve the PMCG regions. I said my review on v3 stood either way, but for the avoidance of doubt, Reviewed-by: Robin Murphy I hadn't considered that a comment is a very good idea, in case the cleanup-script crew find this in future and try to "simplify" it :) Thanks, Robin. > Suggested-by: Robin Murphy > Signed-off-by: Zhen Lei > --- > drivers/perf/arm_smmuv3_pmu.c | 25 +++++++++++++++++++------ > 1 file changed, 19 insertions(+), 6 deletions(-) > > diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c > index 74474bb322c3f26..5e894f957c7b935 100644 > --- a/drivers/perf/arm_smmuv3_pmu.c > +++ b/drivers/perf/arm_smmuv3_pmu.c > @@ -793,17 +793,30 @@ static int smmu_pmu_probe(struct platform_device *pdev) > .capabilities = PERF_PMU_CAP_NO_EXCLUDE, > }; > > - smmu_pmu->reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res_0); > - if (IS_ERR(smmu_pmu->reg_base)) > - return PTR_ERR(smmu_pmu->reg_base); > + /* > + * The register spaces of the PMCG may be in the register space of > + * other devices. For example, SMMU. Therefore, the PMCG resources are > + * not reserved to avoid resource conflicts with other drivers. > + */ > + res_0 = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res_0) > + return ERR_PTR(-EINVAL); > + smmu_pmu->reg_base = devm_ioremap(dev, res_0->start, resource_size(res_0)); > + if (!smmu_pmu->reg_base) > + return ERR_PTR(-ENOMEM); > > cfgr = readl_relaxed(smmu_pmu->reg_base + SMMU_PMCG_CFGR); > > /* Determine if page 1 is present */ > if (cfgr & SMMU_PMCG_CFGR_RELOC_CTRS) { > - smmu_pmu->reloc_base = devm_platform_ioremap_resource(pdev, 1); > - if (IS_ERR(smmu_pmu->reloc_base)) > - return PTR_ERR(smmu_pmu->reloc_base); > + struct resource *res_1; > + > + res_1 = platform_get_resource(pdev, IORESOURCE_MEM, 1); > + if (!res_1) > + return ERR_PTR(-EINVAL); > + smmu_pmu->reloc_base = devm_ioremap(dev, res_1->start, resource_size(res_1)); > + if (!smmu_pmu->reloc_base) > + return ERR_PTR(-ENOMEM); > } else { > smmu_pmu->reloc_base = smmu_pmu->reg_base; > } >