From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size Date: Tue, 27 Jan 2015 11:12:32 +0000 Message-ID: <54C772A0.2000203@arm.com> References: <1422052359-12384-1-git-send-email-m-karicheri2@ti.com> <1422052359-12384-7-git-send-email-m-karicheri2@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <1422052359-12384-7-git-send-email-m-karicheri2-l0cyMroinI0@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Murali Karicheri , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" List-Id: devicetree@vger.kernel.org Hi Murali, 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. Robin. > dev->archdata.dma_coherent = coherent; > if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu)) > dma_ops = arm_get_iommu_dma_map_ops(coherent); > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html