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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	iommu@lists.linux-foundation.org, Christoph Hellwig <hch@lst.de>,
	Kishon Vijay Abraham I <kishon@ti.com>
Subject: [PATCH AUTOSEL 5.4 22/78] dma-direct: fix data truncation in dma_direct_get_required_mask()
Date: Sat, 18 Apr 2020 10:39:51 -0400	[thread overview]
Message-ID: <20200418144047.9013-22-sashal@kernel.org> (raw)
In-Reply-To: <20200418144047.9013-1-sashal@kernel.org>

From: Kishon Vijay Abraham I <kishon@ti.com>

[ Upstream commit cdcda0d1f8f4ab84efe7cd9921c98364398aefd7 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/dma/direct.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 867fd72cb2605..0a093a675b632 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -45,7 +45,8 @@ static inline dma_addr_t phys_to_dma_direct(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;
 }
-- 
2.20.1

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  parent reply	other threads:[~2020-04-18 14:41 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-18 14:39 [PATCH AUTOSEL 5.4 01/78] iommu/amd: Fix the configuration of GCR3 table root pointer Sasha Levin
2020-04-18 14:39 ` [PATCH AUTOSEL 5.4 05/78] iommu/vt-d: Fix page request descriptor size Sasha Levin
2020-04-18 14:39 ` [PATCH AUTOSEL 5.4 07/78] iommu/vt-d: Fix mm reference leak Sasha Levin
2020-04-18 14:39 ` Sasha Levin [this message]
2020-04-18 14:39 ` [PATCH AUTOSEL 5.4 23/78] dma-debug: fix displaying of dma allocation type Sasha Levin
2020-04-18 14:40 ` [PATCH AUTOSEL 5.4 42/78] iommu/virtio: Fix freeing of incomplete domains Sasha Levin
2020-04-18 14:40 ` [PATCH AUTOSEL 5.4 43/78] iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr() Sasha Levin

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