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authorOleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>2017-02-27 13:30:25 +0100
committerWill Deacon <will.deacon@arm.com>2017-03-10 19:23:34 +0100
commited46e66cc1b3d684042f92dfa2ab15ee917b4cac (patch)
treea0307607cdfb450cabc1494fd2bc9945d967bdb3 /drivers/iommu/io-pgtable-arm.c
parentLinux 4.11-rc1 (diff)
downloadlinux-ed46e66cc1b3d684042f92dfa2ab15ee917b4cac.tar.xz
linux-ed46e66cc1b3d684042f92dfa2ab15ee917b4cac.zip
iommu/io-pgtable-arm: 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>
Diffstat (limited to 'drivers/iommu/io-pgtable-arm.c')
-rw-r--r--drivers/iommu/io-pgtable-arm.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index feacc54bec68..f9bc6ebb8140 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -335,8 +335,12 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS)
pte |= ARM_LPAE_PTE_NSTABLE;
__arm_lpae_set_pte(ptep, pte, cfg);
- } else {
+ } else if (!iopte_leaf(pte, lvl)) {
cptep = iopte_deref(pte, data);
+ } else {
+ /* We require an unmap first */
+ WARN_ON(!selftest_running);
+ return -EEXIST;
}
/* Rinse, repeat */