From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f44.google.com ([209.85.215.44]:35592 "EHLO mail-lf0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933881AbcDMN3U (ORCPT ); Wed, 13 Apr 2016 09:29:20 -0400 Received: by mail-lf0-f44.google.com with SMTP id c126so69670446lfb.2 for ; Wed, 13 Apr 2016 06:29:19 -0700 (PDT) Date: Wed, 13 Apr 2016 15:29:17 +0200 From: Niklas =?iso-8859-1?Q?S=F6derlund?= Subject: Re: [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource Message-ID: <20160413132916.GC19650@bigcity.dyn.berto.se> References: <1457404974-1800-1-git-send-email-niklas.soderlund+renesas@ragnatech.se> <20160311125846.GF1111@bigcity.dyn.berto.se> <20160315082254.GE9136@infradead.org> <3286525.zPAGiD4Xk2@avalon> <20160321152601.GA11674@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160321152601.GA11674@infradead.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Christoph Hellwig Cc: Laurent Pinchart , Dan Williams , Vinod Koul , linux-renesas-soc@vger.kernel.org, "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "dmaengine@vger.kernel.org" , iommu@lists.linux-foundation.org, robin.murphy@arm.com, geert+renesas@glider.be, Linus Walleij , Arnd Bergmann , linux-arch@vger.kernel.org Message-ID: <20160413132917.PiK2qCAMd4vsveSGKioKVKtqvzX6GJSiaUWjJs3Fh-A@z> Hi Christoph, On 2016-03-21 08:26:01 -0700, Christoph Hellwig wrote: > On Thu, Mar 17, 2016 at 01:33:51PM +0200, Laurent Pinchart wrote: > > The good news is that, given that no code uses this new API at the moment, > > there isn't much to audit. The patch series implements the resource mapping > > for arch/arm only, and makes use of it in the rcar-dmac driver only. Would you > > like anything audited else than the arch/arm dma mapping implementation, the > > rcar-dmac driver and the code that then deals with the dma addresses (I'm > > thinking about the IOMMU subsystem and the ipmmu-vmsa driver in particular) ? > > Yes, it would be good to do an audit of all the ARM dma_ops as well > as generic code like drivers/base/dma-*.c, lib/dma-debug.c and > include/linux/dma-*.h I have now done an audit to the best of my abilities, thanks to Laurent for pointing me in the right direction. And from what I can tell we are good. * drivers/dma/sh/rcar-dmac.c Once the phys_addr_t is mapped to a dma_addr_t using dma_map_resource() it is only used to check that the transfere do not cross 4GB boundaries and then only directly written to HW registers. * drivers/iommu/iommu.c - iommu_map() Check that it's align to min page size or return -EINVAL then calls domain->ops->map() * drivers/iommu/ipmmu-vmsa.c - ipmmu_map() No logic only calls domain->ops->map() * drivers/iommu/io-pgtable-arm.c - arm_lpae_map() No logic only calls __arm_lpae_map() - __arm_lpae_map() No logic only calls arm_lpae_init_pte() - arm_lpae_init_pte() Used to get a pte: pte |= pfn_to_iopte(paddr >> data->pg_shift, data); * drivers/iommu/io-pgtable-arm-v7s.c - arm_v7s_map() No logic only calls __arm_v7s_map() - __arm_v7s_map() No logic only calls arm_v7s_init_pte() - arm_v7s_init_pte Used to get a pte: pte |= paddr & ARM_V7S_LVL_MASK(lvl); * ARM dma-mapping - dma_unmap_* Only valid unmap is dma_unmap_resource() all others are an invalid use case. - dma_sync_single_* Invalid use case, memmory that is mapped is device memmory - dma_common_mmap() and dma_mmap_attrs() Invalid use case - dma_common_get_sgtable() and dma_get_sgtable_attrs() Invalid use case, only for dma_alloc_* allocated memory, - dma_mapping_error() OK -- Regards, Niklas Söderlund