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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 24943C433ED for ; Wed, 28 Apr 2021 10:06:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3A4461026 for ; Wed, 28 Apr 2021 10:06:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239070AbhD1KHE (ORCPT ); Wed, 28 Apr 2021 06:07:04 -0400 Received: from foss.arm.com ([217.140.110.172]:38790 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238456AbhD1KHD (ORCPT ); Wed, 28 Apr 2021 06:07:03 -0400 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 557241FB; Wed, 28 Apr 2021 03:06:18 -0700 (PDT) Received: from [10.57.61.101] (unknown [10.57.61.101]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A06CD3F70D; Wed, 28 Apr 2021 03:06:16 -0700 (PDT) Subject: Re: DMA mapping fill dma_address to 0 To: Corentin Labbe , hch@lst.de, m.szyprowski@samsung.com, iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org References: From: Robin Murphy Message-ID: <6ce3614e-af79-2a36-de83-6cbb4d9fe9a4@arm.com> Date: Wed, 28 Apr 2021 11:06:10 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: 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 2021-04-28 09:42, Corentin Labbe wrote: > Hello > > I work on the crypto offloader driver of cortina/gemini SL3516 SoC. > I test it by filling a LUKS2 partition. > I got a reproductible problem when handling skcipher requests. > I use dma_map_sg() and when iterating other the result, sg_dma_address(sg) return 0. > But sg_dma_len(sg) is still correct (4096 in my case). > > Below is a simplified view of my code: > nr_sgs = dma_map_sg(ce->dev, areq->src, sg_nents(areq->src), DMA_TO_DEVICE); > (nr_sgs = 1 in my case) > sg = areq->src; > if (!sg_dma_address(sg)) > FAIL What is this check supposed to be for in the first place? 0 is a valid DMA address, because it's also a valid physical address, and I recall RAM at PA 0 on Hikey 960 flushing out some bugs in the past when we tried to use 0 for DMA_MAPPING_ERROR. All the Gemini DTs appear to show RAM starting at PA 0 too, so I'd have to guess that it's simply the case that your DMA buffer happened to end up using that particular page. Robin. > I have digged to find what do dma_map_sg() and I have added some debug. > sg_page(sg) return c7efb000 for example so sg_page() works. > But it seems the problem is that page_to_phys(sg_page(sg)) return 0. > > This problem does not appear immediatly, luksOpen and subsequent fsck always work. > But it appears fast after, when mouting or rsync files in it. > > I have added CONFIG_DEBUG_SG, CONFIG_DMA_API_DEBUG, CONFIG_DMA_API_DEBUG_SG but they didnt bringed any more hints. > Only "DMA-API: cacheline tracking ENOMEM, dma-debug disabled" appears but always with some "time" between my problem and its display. > So I am not sure it is related. > > Regards > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu >