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From: Robin Murphy <robin.murphy@arm.com>
To: will@kernel.org
Cc: iommu@lists.linux-foundation.org, jcrouse@codeaurora.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 03/10] iommu/io-pgtable-arm: Simplify bounds checks
Date: Fri, 25 Oct 2019 19:08:32 +0100	[thread overview]
Message-ID: <d99122bf95b9a28e53ab416f19b0ea7082c933cf.1572024120.git.robin.murphy@arm.com> (raw)
In-Reply-To: <cover.1572024119.git.robin.murphy@arm.com>

We're merely checking that the relevant upper bits of each address
are all zero, so there are cheaper ways to achieve that.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/io-pgtable-arm.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 2cef0f5335e4..a9dff0ecf0c3 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -491,8 +491,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 	if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
 		return -EINVAL;
 
-	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) ||
-		    paddr >= (1ULL << data->iop.cfg.oas)))
+	if (WARN_ON(iova >> data->iop.cfg.ias || paddr >> data->iop.cfg.oas))
 		return -ERANGE;
 
 	prot = arm_lpae_prot_to_pte(data, iommu_prot);
@@ -663,7 +662,7 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
 	if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
 		return 0;
 
-	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
+	if (WARN_ON(iova >> data->iop.cfg.ias))
 		return 0;
 
 	return __arm_lpae_unmap(data, gather, iova, size, lvl, ptep);
-- 
2.21.0.dirty


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  parent reply	other threads:[~2019-10-25 18:09 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-25 18:08 [PATCH v2 00/10] iommu/io-pgtable: Cleanup and prep for split tables Robin Murphy
2019-10-25 18:08 ` [PATCH v2 01/10] iommu/io-pgtable: Make selftest gubbins consistently __init Robin Murphy
2019-10-25 18:08 ` [PATCH v2 02/10] iommu/io-pgtable-arm: Rationalise size check Robin Murphy
2019-10-25 18:08 ` Robin Murphy [this message]
2019-10-25 18:08 ` [PATCH v2 04/10] iommu/io-pgtable-arm: Simplify start level lookup Robin Murphy
2019-10-25 18:08 ` [PATCH v2 05/10] iommu/io-pgtable-arm: Simplify PGD size handling Robin Murphy
2019-10-25 18:08 ` [PATCH v2 06/10] iommu/io-pgtable-arm: Simplify level indexing Robin Murphy
2019-11-04 18:17   ` Will Deacon
2019-11-04 18:36     ` Robin Murphy
2019-11-04 19:20       ` Will Deacon
2019-10-25 18:08 ` [PATCH v2 07/10] iommu/io-pgtable-arm: Rationalise MAIR handling Robin Murphy
2019-11-04 18:20   ` Will Deacon
2019-11-04 18:43     ` Robin Murphy
2019-11-04 19:20       ` Will Deacon
2019-11-04 19:57         ` Will Deacon
2019-10-25 18:08 ` [PATCH v2 08/10] iommu/io-pgtable-arm: Rationalise TTBRn handling Robin Murphy
2019-10-28 15:09   ` Steven Price
2019-10-28 18:51     ` Robin Murphy
2019-11-04 18:36       ` Will Deacon
2019-11-04 19:12         ` Robin Murphy
2019-11-22 22:40   ` Jordan Crouse
2019-10-25 18:08 ` [PATCH v2 09/10] iommu/io-pgtable-arm: Rationalise TCR handling Robin Murphy
2019-11-04 19:14   ` Will Deacon
2019-11-04 23:27     ` Jordan Crouse
2019-11-20 15:11       ` Will Deacon
2019-11-22 15:51         ` Robin Murphy
2019-11-25  7:58           ` Will Deacon
2019-11-22 22:03   ` Jordan Crouse
2019-10-25 18:08 ` [PATCH v2 10/10] iommu/io-pgtable-arm: Prepare for TTBR1 usage Robin Murphy
2019-11-04 23:40   ` Jordan Crouse
2019-11-20 19:18     ` Will Deacon
2019-11-22 22:03   ` Jordan Crouse
2019-11-04 19:22 ` [PATCH v2 00/10] iommu/io-pgtable: Cleanup and prep for split tables Will Deacon
2019-11-04 20:20   ` Will Deacon
2020-01-10 15:09     ` Will Deacon

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