[PATCH 2/2] arm64/dma-mapping: validate dma_masks against IORT defined limits
Some drivers set the dma_mask of client devices based solely on values read from capability registers which may not account for platform specific bus address width limitations. Fortunately, the ACPI IORT table provides a way to report the effective number of address bits a device can use to access memory. This information, when present, is used to supplement the checks already being done in dma_supported() to avoid setting overly generous dma_masks. Signed-off-by: Nate Watterson--- arch/arm64/mm/dma-mapping.c | 20 +++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index e040827..467fd23 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -19,6 +19,7 @@ #include #include +#include #include #include #include @@ -347,6 +348,12 @@ static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt, static int __swiotlb_dma_supported(struct device *hwdev, u64 mask) { + int dma_limit; + + dma_limit = iort_get_memory_address_limit(hwdev); + if (dma_limit >= 0 && DMA_BIT_MASK(dma_limit) < mask) + return 0; + if (swiotlb) return swiotlb_dma_supported(hwdev, mask); return 1; @@ -784,6 +791,17 @@ static void __iommu_unmap_sg_attrs(struct device *dev, iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs); } +static int __iommu_dma_supported(struct device *hwdev, u64 mask) +{ + int dma_limit; + + dma_limit = iort_get_memory_address_limit(hwdev); + if (dma_limit >= 0 && DMA_BIT_MASK(dma_limit) < mask) + return 0; + + return iommu_dma_supported(hwdev, mask); +} + static struct dma_map_ops iommu_dma_ops = { .alloc = __iommu_alloc_attrs, .free = __iommu_free_attrs, @@ -799,7 +817,7 @@ static void __iommu_unmap_sg_attrs(struct device *dev, .sync_sg_for_device = __iommu_sync_sg_for_device, .map_resource = iommu_dma_map_resource, .unmap_resource = iommu_dma_unmap_resource, - .dma_supported = iommu_dma_supported, + .dma_supported = __iommu_dma_supported, .mapping_error = iommu_dma_mapping_error, }; -- Qualcomm Datacenter Technologies, Inc. on behalf of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
[PATCH 2/2] arm64/dma-mapping: validate dma_masks against IORT defined limits
Some drivers set the dma_mask of client devices based solely on values read from capability registers which may not account for platform specific bus address width limitations. Fortunately, the ACPI IORT table provides a way to report the effective number of address bits a device can use to access memory. This information, when present, is used to supplement the checks already being done in dma_supported() to avoid setting overly generous dma_masks. Signed-off-by: Nate Watterson --- arch/arm64/mm/dma-mapping.c | 20 +++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index e040827..467fd23 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -19,6 +19,7 @@ #include #include +#include #include #include #include @@ -347,6 +348,12 @@ static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt, static int __swiotlb_dma_supported(struct device *hwdev, u64 mask) { + int dma_limit; + + dma_limit = iort_get_memory_address_limit(hwdev); + if (dma_limit >= 0 && DMA_BIT_MASK(dma_limit) < mask) + return 0; + if (swiotlb) return swiotlb_dma_supported(hwdev, mask); return 1; @@ -784,6 +791,17 @@ static void __iommu_unmap_sg_attrs(struct device *dev, iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs); } +static int __iommu_dma_supported(struct device *hwdev, u64 mask) +{ + int dma_limit; + + dma_limit = iort_get_memory_address_limit(hwdev); + if (dma_limit >= 0 && DMA_BIT_MASK(dma_limit) < mask) + return 0; + + return iommu_dma_supported(hwdev, mask); +} + static struct dma_map_ops iommu_dma_ops = { .alloc = __iommu_alloc_attrs, .free = __iommu_free_attrs, @@ -799,7 +817,7 @@ static void __iommu_unmap_sg_attrs(struct device *dev, .sync_sg_for_device = __iommu_sync_sg_for_device, .map_resource = iommu_dma_map_resource, .unmap_resource = iommu_dma_unmap_resource, - .dma_supported = iommu_dma_supported, + .dma_supported = __iommu_dma_supported, .mapping_error = iommu_dma_mapping_error, }; -- Qualcomm Datacenter Technologies, Inc. on behalf of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.