[PATCH 5.10 72/79] swiotlb: avoid potential left shift overflow

Greg Kroah-Hartman
2022-09-13T14:56:28Z

From: Chao Gao <chao.gao@intel.com>

[ Upstream commit 3f0461613ebcdc8c4073e235053d06d5aa58750f ]

The second operand passed to slot_addr() is declared as int or unsigned int
in all call sites. The left-shift to get the offset of a slot can overflow
if swiotlb size is larger than 4G.

Convert the macro to an inline function and declare the second argument as
phys_addr_t to avoid the potential overflow.

Fixes: 26a7e094783d ("swiotlb: refactor swiotlb_tbl_map_single")
Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/dma/swiotlb.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 274587a57717f..4a9831d01f0ea 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -452,7 +452,10 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
}
}

-#define slot_addr(start, idx) ((start) + ((idx) << IO_TLB_SHIFT))
+static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx)
+{
+ return start + (idx << IO_TLB_SHIFT);
+}

/*
* Return the offset into a iotlb slot required to keep the device happy.
--
2.35.1