[PATCH v2 03/10] iommu/io-pgtable-arm: Simplify bounds checks
Robin Murphy
robin.murphy at arm.com
Fri Oct 25 18:08:32 UTC 2019
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 at 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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