Regardless of swiotlb setting, the restricted DMA pool is preferred if available.
The restricted DMA pools provide a basic level of protection against the DMA overwriting buffer contents at unexpected times. However, to protect against general data leakage and system memory corruption, the system needs to provide a way to lock down the memory access, e.g., MPU.
Note that is_dev_swiotlb_force doesn't check if swiotlb_force == SWIOTLB_FORCE. Otherwise the memory allocation behavior with default swiotlb will be changed by the following patche ("dma-direct: Allocate memory from restricted DMA pool if available").
Signed-off-by: Claire Chang tientzu@chromium.org --- include/linux/swiotlb.h | 13 +++++++++++++ kernel/dma/direct.h | 3 ++- kernel/dma/swiotlb.c | 8 ++++---- 3 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index c530c976d18b..0c5a18d9cf89 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -120,6 +120,15 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr) return mem && paddr >= mem->start && paddr < mem->end; }
+static inline bool is_dev_swiotlb_force(struct device *dev) +{ +#ifdef CONFIG_DMA_RESTRICTED_POOL + if (dev->dma_io_tlb_mem) + return true; +#endif /* CONFIG_DMA_RESTRICTED_POOL */ + return false; +} + void __init swiotlb_exit(void); unsigned int swiotlb_max_segment(void); size_t swiotlb_max_mapping_size(struct device *dev); @@ -131,6 +140,10 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr) { return false; } +static inline bool is_dev_swiotlb_force(struct device *dev) +{ + return false; +} static inline void swiotlb_exit(void) { } diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index 13e9e7158d94..f94813674e23 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -87,7 +87,8 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys);
- if (unlikely(swiotlb_force == SWIOTLB_FORCE)) + if (unlikely(swiotlb_force == SWIOTLB_FORCE) || + is_dev_swiotlb_force(dev)) return swiotlb_map(dev, phys, size, dir, attrs);
if (unlikely(!dma_capable(dev, dma_addr, size, true))) { diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 1d221343f1c8..96ff36d8ec53 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -344,7 +344,7 @@ void __init swiotlb_exit(void) static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir) { - struct io_tlb_mem *mem = io_tlb_default_mem; + struct io_tlb_mem *mem = get_io_tlb_mem(dev); int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT; phys_addr_t orig_addr = mem->slots[index].orig_addr; size_t alloc_size = mem->slots[index].alloc_size; @@ -426,7 +426,7 @@ static unsigned int wrap_index(struct io_tlb_mem *mem, unsigned int index) static int find_slots(struct device *dev, phys_addr_t orig_addr, size_t alloc_size) { - struct io_tlb_mem *mem = io_tlb_default_mem; + struct io_tlb_mem *mem = get_io_tlb_mem(dev); unsigned long boundary_mask = dma_get_seg_boundary(dev); dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(dev, mem->start) & boundary_mask; @@ -503,7 +503,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, size_t mapping_size, size_t alloc_size, enum dma_data_direction dir, unsigned long attrs) { - struct io_tlb_mem *mem = io_tlb_default_mem; + struct io_tlb_mem *mem = get_io_tlb_mem(dev); unsigned int offset = swiotlb_align_offset(dev, orig_addr); unsigned int i; int index; @@ -554,7 +554,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, size_t mapping_size, enum dma_data_direction dir, unsigned long attrs) { - struct io_tlb_mem *mem = io_tlb_default_mem; + struct io_tlb_mem *mem = get_io_tlb_mem(hwdev); unsigned long flags; unsigned int offset = swiotlb_align_offset(hwdev, tlb_addr); int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;