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authorNicolas Saenz Julienne <nsaenzjulienne@suse.de>2019-11-07 16:06:44 +0100
committerChristoph Hellwig <hch@lst.de>2019-11-11 10:52:18 +0100
commitb12d66278dd627cbe1ea7c000aa4715aaf8830c8 (patch)
tree6ed0eb01fd50f5035d8808ba9fee7c2e85960506 /include/linux/dma-direct.h
parent5e76f564572b85735de4b75a5e73b514be2562be (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>
Diffstat (limited to 'include/linux/dma-direct.h')
-rw-r--r--include/linux/dma-direct.h12
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 */