From: Robin Murphy <robin.murphy@arm.com>
Date: Fri, 25 Oct 2019 19:08:32 +0100
Subject: iommu/io-pgtable-arm: Simplify bounds checks
Git-commit: 67f3e53d2a37ab27b00610eb25724103055beafc
Patch-mainline: v5.5-rc1
References: bsc#1175713

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>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 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 abe794576e8f..5da3cbdb76f7 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);