diff options
| author | Kishon Vijay Abraham I <kishon@ti.com> | 2020-04-06 10:58:36 +0530 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-04-08 20:52:24 +0200 |
| commit | cdcda0d1f8f4ab84efe7cd9921c98364398aefd7 (patch) | |
| tree | 6e1d686f922eb225bac1ba2f89d8363598eee906 /kernel/dma/direct.c | |
| parent | f5e94d10e4c468357019e5c28d48499f677b284f (diff) | |
| download | lwn-cdcda0d1f8f4ab84efe7cd9921c98364398aefd7.tar.gz lwn-cdcda0d1f8f4ab84efe7cd9921c98364398aefd7.zip | |
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/direct.c')
| -rw-r--r-- | kernel/dma/direct.c | 3 |
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; } |