diff mbox series

[v2,03/10] iommu/io-pgtable-arm: Simplify bounds checks

Message ID d99122bf95b9a28e53ab416f19b0ea7082c933cf.1572024120.git.robin.murphy@arm.com (mailing list archive)
State New, archived
Headers show
Series iommu/io-pgtable: Cleanup and prep for split tables | expand

Commit Message

Robin Murphy Oct. 25, 2019, 6:08 p.m. UTC 
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 mbox series

Patch

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);