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

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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>
This commit is contained in:
Oleksandr Tyshchenko 2017-02-27 14:30:26 +02:00 committed by Will Deacon
parent ed46e66cc1
commit a03849e721
1 changed files with 5 additions and 1 deletions
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6
drivers/iommu/io-pgtable-arm-v7s.c
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@ -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 */