Commit a03849e7 authored Feb 27, 2017 by Oleksandr Tyshchenko Committed by Will Deacon Mar 10, 2017

iommu/io-pgtable-arm-v7s: Check for leaf entry before dereferencing it



Do a check for already installed leaf entry at the current level before
dereferencing it in order to avoid walking the page table down with
wrong pointer to the next level.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent ed46e66c

drivers/iommu/io-pgtable-arm-v7s.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -422,8 +422,12 @@ static int __arm_v7s_map(struct arm_v7s_io_pgtable *data, unsigned long iova,
		pte \|= ARM_V7S_ATTR_NS_TABLE;

		__arm_v7s_set_pte(ptep, pte, 1, cfg);
		} else {
		} else if (ARM_V7S_PTE_IS_TABLE(pte, lvl)) {
		cptep = iopte_deref(pte, lvl);
		} else {
		/* We require an unmap first */
		WARN_ON(!selftest_running);
		return -EEXIST;
		}

		/* Rinse, repeat */

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