From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754980AbcGKPHF (ORCPT ); Mon, 11 Jul 2016 11:07:05 -0400 Received: from foss.arm.com ([217.140.101.70]:53580 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753898AbcGKPHD (ORCPT ); Mon, 11 Jul 2016 11:07:03 -0400 Subject: Re: [PATCH v2 5/6] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED_EXECUTABLE To: Mitchel Humpherys , iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Will Deacon , Marek Szyprowski References: <20160709020919.6760-1-mitchelh@codeaurora.org> <20160709020919.6760-6-mitchelh@codeaurora.org> Cc: Jordan Crouse , Jeremy Gebben , Patrick Daly , Pratik Patel From: Robin Murphy Message-ID: <5783B60E.3050907@arm.com> Date: Mon, 11 Jul 2016 16:06:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <20160709020919.6760-6-mitchelh@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/07/16 03:09, Mitchel Humpherys wrote: > The newly added DMA_ATTR_PRIVILEGED_EXECUTABLE is useful for creating > mappings that are executable by privileged DMA engines. Implement it in > dma-iommu.c so that the ARM64 DMA IOMMU mapper can make use of it. > > Signed-off-by: Mitchel Humpherys > --- > arch/arm64/mm/dma-mapping.c | 6 +++--- > drivers/iommu/dma-iommu.c | 15 +++++++++++---- > include/linux/dma-iommu.h | 3 ++- > 3 files changed, 16 insertions(+), 8 deletions(-) > > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c > index c566ec83719f..44f676268df6 100644 > --- a/arch/arm64/mm/dma-mapping.c > +++ b/arch/arm64/mm/dma-mapping.c > @@ -543,7 +543,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size, > struct dma_attrs *attrs) > { > bool coherent = is_device_dma_coherent(dev); > - int ioprot = dma_direction_to_prot(DMA_BIDIRECTIONAL, coherent); > + int ioprot = dma_direction_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); > size_t iosize = size; > void *addr; > > @@ -697,7 +697,7 @@ static dma_addr_t __iommu_map_page(struct device *dev, struct page *page, > struct dma_attrs *attrs) > { > bool coherent = is_device_dma_coherent(dev); > - int prot = dma_direction_to_prot(dir, coherent); > + int prot = dma_direction_to_prot(dir, coherent, attrs); > dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot); > > if (!iommu_dma_mapping_error(dev, dev_addr) && > @@ -755,7 +755,7 @@ static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl, > __iommu_sync_sg_for_device(dev, sgl, nelems, dir); > > return iommu_dma_map_sg(dev, sgl, nelems, > - dma_direction_to_prot(dir, coherent)); > + dma_direction_to_prot(dir, coherent, attrs)); > } > > static void __iommu_unmap_sg_attrs(struct device *dev, > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index ea5a9ebf0f78..ccc6219da228 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -132,23 +132,30 @@ EXPORT_SYMBOL(iommu_dma_init_domain); > * dma_direction_to_prot - Translate DMA API directions to IOMMU API page flags Privilege really isn't a direction :( If we're going to cram more into this function it really wants renaming and redocumenting. > * @dir: Direction of DMA transfer > * @coherent: Is the DMA master cache-coherent? > + * @attrs: DMA attributes for the mapping > * > * Return: corresponding IOMMU API page protection flags > */ > -int dma_direction_to_prot(enum dma_data_direction dir, bool coherent) > +int dma_direction_to_prot(enum dma_data_direction dir, bool coherent, > + struct dma_attrs *attrs) > { > int prot = coherent ? IOMMU_CACHE : 0; > > switch (dir) { > case DMA_BIDIRECTIONAL: > - return prot | IOMMU_READ | IOMMU_WRITE; > + prot |= IOMMU_READ | IOMMU_WRITE; > case DMA_TO_DEVICE: > - return prot | IOMMU_READ; > + prot |= IOMMU_READ; > case DMA_FROM_DEVICE: > - return prot | IOMMU_WRITE; > + prot |= IOMMU_WRITE; > default: > return 0; > } > + if (dma_get_attr(DMA_ATTR_PRIVILEGED_EXECUTABLE, attrs)) { > + prot &= ~IOMMU_WRITE; Hey, we didn't say anything anywhere about anything being privileged read-only! Frankly, I think this is going to create more problems that it solves. Implementing IOMMU_PRIV as simply unprivileged no-access should be sufficient. Robin. > + prot |= IOMMU_PRIV; > + } > + return prot; > } > > static struct iova *__alloc_iova(struct iova_domain *iovad, size_t size, > diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h > index 8443bbb5c071..d5a37e58d29b 100644 > --- a/include/linux/dma-iommu.h > +++ b/include/linux/dma-iommu.h > @@ -32,7 +32,8 @@ void iommu_put_dma_cookie(struct iommu_domain *domain); > int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size); > > /* General helpers for DMA-API <-> IOMMU-API interaction */ > -int dma_direction_to_prot(enum dma_data_direction dir, bool coherent); > +int dma_direction_to_prot(enum dma_data_direction dir, bool coherent, > + struct dma_attrs *attrs); > > /* > * These implement the bulk of the relevant DMA mapping callbacks, but require >