[PATCH v2 5/6] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED_EXECUTABLE
From: robin.murphy@arm.com (Robin Murphy)
Date: 2016-07-11 15:07:05
Also in:
linux-iommu, lkml
On 09/07/16 03:09, Mitchel Humpherys wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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.
quoted hunk ↗ jump to hunk
+ 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