From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com> Do a check for already installed leaf entry at the current level before performing any actions when trying to map.
This check is already present in arm_v7s_init_pte(), i.e. before installing new leaf entry at the current level if conditions to do so are met (num_entries > 0). But, this might be insufficient in case when we have already installed block mapping at this level and it is not time to install new leaf entry (num_entries == 0). In that case we continue walking the page table down with wrong pointer to the next level. So, move check from arm_v7s_init_pte() to __arm_v7s_map() in order to avoid all cases. Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com> --- This patch does similar things as the patch I have pushed a week ago for long-descriptor format [1]. The reason why this patch is RFC is because I am not sure I did the right thing and I even didn't test it. [1] https://lists.linuxfoundation.org/pipermail/iommu/2017-February/020411.html --- --- drivers/iommu/io-pgtable-arm-v7s.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c index f50e51c..7f7594b 100644 --- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -364,10 +364,6 @@ static int arm_v7s_init_pte(struct arm_v7s_io_pgtable *data, if (WARN_ON(__arm_v7s_unmap(data, iova + i * sz, sz, lvl, tblp) != sz)) return -EINVAL; - } else if (ptep[i]) { - /* We require an unmap first */ - WARN_ON(!selftest_running); - return -EEXIST; } pte |= ARM_V7S_PTE_TYPE_PAGE; @@ -392,11 +388,20 @@ static int __arm_v7s_map(struct arm_v7s_io_pgtable *data, unsigned long iova, { struct io_pgtable_cfg *cfg = &data->iop.cfg; arm_v7s_iopte pte, *cptep; - int num_entries = size >> ARM_V7S_LVL_SHIFT(lvl); + int i = 0, num_entries = size >> ARM_V7S_LVL_SHIFT(lvl); /* Find our entry at the current level */ ptep += ARM_V7S_LVL_IDX(iova, lvl); + /* Check for already installed leaf entry */ + do { + if (ptep[i] && !ARM_V7S_PTE_IS_TABLE(ptep[i], lvl)) { + /* We require an unmap first */ + WARN_ON(!selftest_running); + return -EEXIST; + } + } while (++i < num_entries); + /* If we can install a leaf entry at this level, then do so */ if (num_entries) return arm_v7s_init_pte(data, iova, paddr, prot, -- 2.7.4 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
