From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758569AbbA0PU3 (ORCPT ); Tue, 27 Jan 2015 10:20:29 -0500 Received: from comal.ext.ti.com ([198.47.26.152]:42350 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737AbbA0PU0 (ORCPT ); Tue, 27 Jan 2015 10:20:26 -0500 Message-ID: <54C7AC9B.1040308@ti.com> Date: Tue, 27 Jan 2015 10:19:55 -0500 From: Murali Karicheri User-Agent: Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Catalin Marinas CC: Robin Murphy , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "devicetree@vger.kernel.org" , "iommu@lists.linux-foundation.org" Subject: Re: [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <1422052359-12384-7-git-send-email-m-karicheri2@ti.com> <54C772A0.2000203@arm.com> <20150127113416.GB3226@e104818-lin.cambridge.arm.com> In-Reply-To: <20150127113416.GB3226@e104818-lin.cambridge.arm.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/27/2015 06:34 AM, Catalin Marinas wrote: > On Tue, Jan 27, 2015 at 11:12:32AM +0000, Robin Murphy wrote: >> On 23/01/15 22:32, Murali Karicheri wrote: >>> Limit the dma_mask to minimum of dma_mask and dma_base + size - 1. >>> >>> Also arm_iommu_create_mapping() has size parameter of size_t and >>> arm_setup_iommu_dma_ops() can take a value higher than that. So >>> limit the size to SIZE_MAX. >>> >>> Signed-off-by: Murali Karicheri >>> --- >>> arch/arm/mm/dma-mapping.c | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c >>> index 7864797..a1f9030 100644 >>> --- a/arch/arm/mm/dma-mapping.c >>> +++ b/arch/arm/mm/dma-mapping.c >>> @@ -2004,6 +2004,13 @@ static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size, >>> if (!iommu) >>> return false; >>> >>> + /* >>> + * currently arm_iommu_create_mapping() takes a max of size_t >>> + * for size param. So check this limit for now. >>> + */ >>> + if (size> SIZE_MAX) >>> + return false; >>> + >>> mapping = arm_iommu_create_mapping(dev->bus, dma_base, size); >>> if (IS_ERR(mapping)) { >>> pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n", >>> @@ -2053,6 +2060,9 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, >>> { >>> struct dma_map_ops *dma_ops; >>> >>> + /* limit dma_mask to the lower of the two values */ >>> + *dev->dma_mask = min((*dev->dma_mask), (dma_base + size - 1)); >>> + >> >> Is there any reason not to do this in of_dma_configure? It seems like >> something everyone could benefit from - I'd cooked up a dodgy workaround >> for the same issue in my arm64 IOMMU code, but handling it generically >> in common code would be much nicer. Ok Will move this to of_dma_configure(). Murali > > I agree. I started something here: > > http://article.gmane.org/gmane.linux.kernel/1835096 > > but I don't remember to have got to a clear conclusion. > -- Murali Karicheri Linux Kernel, Texas Instruments