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authorKishon Vijay Abraham I <kishon@ti.com>2020-04-06 08:28:36 +0300
committerChristoph Hellwig <hch@lst.de>2020-04-08 21:52:24 +0300
commitcdcda0d1f8f4ab84efe7cd9921c98364398aefd7 (patch)
tree6e1d686f922eb225bac1ba2f89d8363598eee906 /kernel/dma
parentf5e94d10e4c468357019e5c28d48499f677b284f (diff)
downloadlinux-cdcda0d1f8f4ab84efe7cd9921c98364398aefd7.tar.xz
dma-direct: fix data truncation in dma_direct_get_required_mask()
The upper 32-bit physical address gets truncated inadvertently when dma_direct_get_required_mask() invokes phys_to_dma_direct(). This results in dma_addressing_limited() return incorrect value when used in platforms with LPAE enabled. Fix it here by explicitly type casting 'max_pfn' to phys_addr_t in order to prevent overflow of intermediate value while evaluating '(max_pfn - 1) << PAGE_SHIFT'. Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma')
-rw-r--r--kernel/dma/direct.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index a8560052a915..8f4bbdaf965e 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -39,7 +39,8 @@ static inline struct page *dma_direct_to_page(struct device *dev,
u64 dma_direct_get_required_mask(struct device *dev)
{
- u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT);
+ phys_addr_t phys = (phys_addr_t)(max_pfn - 1) << PAGE_SHIFT;
+ u64 max_dma = phys_to_dma_direct(dev, phys);
return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
}