Linaro-mm-sig January 2013

linaro-mm-sig@lists.linaro.org

30 participants
13 discussions

[PATCH v2] arm: dma mapping: export arm iommu functions

by Prathyush K

This patch adds EXPORT_SYMBOL_GPL calls to the three arm iommu functions - arm_iommu_create_mapping, arm_iommu_free_mapping and arm_iommu_attach_device. These three functions are arm specific wrapper functions for creating/freeing/using an iommu mapping and they are called by various drivers. If any of these drivers need to be built as dynamic modules, these functions need to be exported. Changelog v2: using EXPORT_SYMBOL_GPL as suggested by Marek. Signed-off-by: Prathyush K <prathyush.k(a)samsung.com> --- arch/arm/mm/dma-mapping.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 6b2fb87..226ebcf 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1797,6 +1797,7 @@ err2: err: return ERR_PTR(err); } +EXPORT_SYMBOL_GPL(arm_iommu_create_mapping); static void release_iommu_mapping(struct kref *kref) { @@ -1813,6 +1814,7 @@ void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping) if (mapping) kref_put(&mapping->kref, release_iommu_mapping); } +EXPORT_SYMBOL_GPL(arm_iommu_release_mapping); /** * arm_iommu_attach_device @@ -1841,5 +1843,6 @@ int arm_iommu_attach_device(struct device *dev, pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev)); return 0; } +EXPORT_SYMBOL_GPL(arm_iommu_attach_device); #endif -- 1.8.0

12 years, 3 months

[RFC] ARM: DMA-Mapping: add a new attribute to clear buffer

by daeinki＠gmail.com

From: Inki Dae <inki.dae(a)samsung.com> This patch adds a new attribute, DMA_ATTR_SKIP_BUFFER_CLEAR to skip buffer clearing. The buffer clearing also flushes CPU cache so this operation has performance deterioration a little bit. With this patch, allocated buffer region is cleared as default. So if you want to skip the buffer clearing, just set this attribute. But this flag should be used carefully because this use might get access to some vulnerable content such as security data. So with this patch, we make sure that all pages will be somehow cleared before exposing to userspace. For example, let's say that the security data had been stored in some memory and freed without clearing it. And then malicious process allocated the region though some buffer allocator such as gem and ion without clearing it, and requested blit operation with cleared another buffer though gpu or other drivers. At this time, the malicious process could access the security data. Signed-off-by: Inki Dae <inki.dae(a)samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park(a)samsung.com> --- arch/arm/mm/dma-mapping.c | 6 ++++-- include/linux/dma-attrs.h | 1 + 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 6b2fb87..fbe9dff 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1058,7 +1058,8 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, if (!page) goto error; - __dma_clear_buffer(page, size); + if (!dma_get_attr(DMA_ATTR_SKIP_BUFFER_CLEAR, attrs)) + __dma_clear_buffer(page, size); for (i = 0; i < count; i++) pages[i] = page + i; @@ -1082,7 +1083,8 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, pages[i + j] = pages[i] + j; } - __dma_clear_buffer(pages[i], PAGE_SIZE << order); + if (!dma_get_attr(DMA_ATTR_SKIP_BUFFER_CLEAR, attrs)) + __dma_clear_buffer(pages[i], PAGE_SIZE << order); i += 1 << order; count -= 1 << order; } diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index c8e1831..2592c05 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -18,6 +18,7 @@ enum dma_attr { DMA_ATTR_NO_KERNEL_MAPPING, DMA_ATTR_SKIP_CPU_SYNC, DMA_ATTR_FORCE_CONTIGUOUS, + DMA_ATTR_SKIP_BUFFER_CLEAR, DMA_ATTR_MAX, }; -- 1.7.4.1

12 years, 3 months

[PATCH] arm: dma mapping: export arm iommu functions

by Prathyush K

This patch adds EXPORT_SYMBOL calls to the three arm iommu functions - arm_iommu_create_mapping, arm_iommu_free_mapping and arm_iommu_attach_device. These functions can now be called from dynamic modules. Signed-off-by: Prathyush K <prathyush.k(a)samsung.com> --- arch/arm/mm/dma-mapping.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 6b2fb87..c0f0f43 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1797,6 +1797,7 @@ err2: err: return ERR_PTR(err); } +EXPORT_SYMBOL(arm_iommu_create_mapping); static void release_iommu_mapping(struct kref *kref) { @@ -1813,6 +1814,7 @@ void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping) if (mapping) kref_put(&mapping->kref, release_iommu_mapping); } +EXPORT_SYMBOL(arm_iommu_release_mapping); /** * arm_iommu_attach_device @@ -1841,5 +1843,6 @@ int arm_iommu_attach_device(struct device *dev, pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev)); return 0; } +EXPORT_SYMBOL(arm_iommu_attach_device); #endif -- 1.8.0

12 years, 3 months

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Linaro-mm-sig January 2013