linux-kernel - [PATCH v4 4/7] iommu: Switch gather->end to the inclusive end

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Date:   Thu, 7 Jan 2021 20:29:06 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>
CC:     Matthias Brugger <matthias.bgg@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Tomasz Figa <tfiga@...gle.com>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <iommu@...ts.linux-foundation.org>, <yong.wu@...iatek.com>,
        <youlin.pei@...iatek.com>, Nicolas Boichat <drinkcat@...omium.org>,
        <anan.sun@...iatek.com>, <chao.hao@...iatek.com>,
        Greg Kroah-Hartman <gregkh@...gle.com>,
        <kernel-team@...roid.com>, Christoph Hellwig <hch@...radead.org>,
        David Laight <David.Laight@...LAB.COM>
Subject: [PATCH v4 4/7] iommu: Switch gather->end to the inclusive end

Currently gather->end is "unsigned long" which may be overflow in
arch32 in the corner case: 0xfff00000 + 0x100000(iova + size).
Although it doesn't affect the size(end - start), it affects the checking
"gather->end < end"

This patch changes this "end" to the real end address
(end = start + size - 1). Correspondingly, update the length to
"end - start + 1".

Fixes: a7d20dc19d9e ("iommu: Introduce struct iommu_iotlb_gather for batching TLB flushes")
Signed-off-by: Yong Wu <yong.wu@...iatek.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +-
 drivers/iommu/mtk_iommu.c                   | 2 +-
 drivers/iommu/tegra-gart.c                  | 2 +-
 include/linux/iommu.h                       | 4 ++--
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 8ca7415d785d..c70d6e79f534 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2280,7 +2280,7 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain,
 {
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 
-	arm_smmu_tlb_inv_range(gather->start, gather->end - gather->start,
+	arm_smmu_tlb_inv_range(gather->start, gather->end - gather->start + 1,
 			       gather->pgsize, true, smmu_domain);
 }
 
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index f579fc21971e..66a00a2cb445 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -443,7 +443,7 @@ static void mtk_iommu_iotlb_sync(struct iommu_domain *domain,
 				 struct iommu_iotlb_gather *gather)
 {
 	struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
-	size_t length = gather->end - gather->start;
+	size_t length = gather->end - gather->start + 1;
 
 	if (gather->start == ULONG_MAX)
 		return;
diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index 05e8e19b8269..6f130e51f072 100644
--- a/drivers/iommu/tegra-gart.c
+++ b/drivers/iommu/tegra-gart.c
@@ -270,7 +270,7 @@ static void gart_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
 static void gart_iommu_sync(struct iommu_domain *domain,
 			    struct iommu_iotlb_gather *gather)
 {
-	size_t length = gather->end - gather->start;
+	size_t length = gather->end - gather->start + 1;
 
 	gart_iommu_sync_map(domain, gather->start, length);
 }
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9ce0aa9e236b..ae8eddd4621b 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -170,7 +170,7 @@ enum iommu_dev_features {
  * struct iommu_iotlb_gather - Range information for a pending IOTLB flush
  *
  * @start: IOVA representing the start of the range to be flushed
- * @end: IOVA representing the end of the range to be flushed (exclusive)
+ * @end: IOVA representing the end of the range to be flushed (inclusive)
  * @pgsize: The interval at which to perform the flush
  *
  * This structure is intended to be updated by multiple calls to the
@@ -539,7 +539,7 @@ static inline void iommu_iotlb_gather_add_page(struct iommu_domain *domain,
 					       struct iommu_iotlb_gather *gather,
 					       unsigned long iova, size_t size)
 {
-	unsigned long start = iova, end = start + size;
+	unsigned long start = iova, end = start + size - 1;
 
 	/*
 	 * If the new page is disjoint from the current range or is mapped at
-- 
2.18.0