On Fri, 2020-10-23 at 12:17 +0100, Will Deacon wrote:

On Wed, Sep 30, 2020 at 03:06:31PM +0800, Yong Wu wrote:

quoted

Use the ias for the valid iova checking in arm_v7s_unmap. This is a
preparing patch for supporting iova 34bit for MediaTek.
BTW, change the ias/oas checking format in arm_v7s_map.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/io-pgtable-arm-v7s.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index a688f22cbe3b..4c9d8dccfc5a 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c

@@ -526,8 +526,7 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
 	if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
 		return 0;
 
-	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;

As discussed when reviewing these for Android, please leave this code as-is.

quoted

 
 	ret = __arm_v7s_map(data, iova, paddr, size, prot, 1, data->pgd, gfp);

@@ -717,7 +716,7 @@ static size_t arm_v7s_unmap(struct io_pgtable_ops *ops, unsigned long iova,
 {
 	struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
 
-	if (WARN_ON(upper_32_bits(iova)))
+	if (WARN_ON(iova >> data->iop.cfg.ias))
 		return 0;

And avoid the UB here for 32-bit machines by comparing with 1ULL <<
iop.cfg.ias instead.

Thanks. I will fix it in next version.

Thanks,

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel