diff options
| author | Nicolas Saenz Julienne | 2019-11-07 16:06:44 +0100 |
|---|---|---|
| committer | Christoph Hellwig | 2019-11-11 10:52:18 +0100 |
| commit | b12d66278dd627cbe1ea7c000aa4715aaf8830c8 (patch) | |
| tree | 6ed0eb01fd50f5035d8808ba9fee7c2e85960506 | |
| parent | 5e76f564572b85735de4b75a5e73b514be2562be (diff) | |
dma-direct: check for overflows on 32 bit DMA addresses
As seen on the new Raspberry Pi 4 and sta2x11's DMA implementation it is
possible for a device configured with 32 bit DMA addresses and a partial
DMA mapping located at the end of the address space to overflow. It
happens when a higher physical address, not DMAable, is translated to
it's DMA counterpart.
For example the Raspberry Pi 4, configurable up to 4 GB of memory, has
an interconnect capable of addressing the lower 1 GB of physical memory
with a DMA offset of 0xc0000000. It transpires that, any attempt to
translate physical addresses higher than the first GB will result in an
overflow which dma_capable() can't detect as it only checks for
addresses bigger then the maximum allowed DMA address.
Fix this by verifying in dma_capable() if the DMA address range provided
is at any point lower than the minimum possible DMA address on the bus.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | include/linux/dma-direct.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index bcd953fb1f5a..6db863c3eb93 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -3,8 +3,11 @@ #define _LINUX_DMA_DIRECT_H 1 #include <linux/dma-mapping.h> +#include <linux/memblock.h> /* for min_low_pfn */ #include <linux/mem_encrypt.h> +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr); + #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA #include <asm/dma-direct.h> #else @@ -24,11 +27,16 @@ static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr) static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) { + dma_addr_t end = addr + size - 1; + if (!dev->dma_mask) return false; - return addr + size - 1 <= - min_not_zero(*dev->dma_mask, dev->bus_dma_mask); + if (!IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) && + min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn))) + return false; + + return end <= min_not_zero(*dev->dma_mask, dev->bus_dma_mask); } #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */ |