From: Russell King Date: Mon, 27 Jul 2015 12:29:00 +0000 (+0100) Subject: iommu/tegra-smmu: Fix iova_to_phys() method X-Git-Tag: firefly_0821_release~176^2~1106^2^5^2~15 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9113785c3e918187b6b0c084c60e0344a2f1685c;p=firefly-linux-kernel-4.4.55.git iommu/tegra-smmu: Fix iova_to_phys() method iova_to_phys() has several problems: (a) iova_to_phys() is supposed to return 0 if there is no entry present for the iova. (b) if as_get_pte() fails, we oops the kernel by dereferencing a NULL pointer. Really, we should not even be trying to allocate a page table at all, but should only be returning the presence of the 2nd level page table. This will be fixed in a subsequent patch. Treat both of these conditions as "no mapping" conditions. Signed-off-by: Russell King Signed-off-by: Thierry Reding --- diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c index c1f2e521dc52..083354903a1a 100644 --- a/drivers/iommu/tegra-smmu.c +++ b/drivers/iommu/tegra-smmu.c @@ -592,6 +592,9 @@ static phys_addr_t tegra_smmu_iova_to_phys(struct iommu_domain *domain, u32 *pte; pte = as_get_pte(as, iova, &page); + if (!pte || !*pte) + return 0; + pfn = *pte & as->smmu->pfn_mask; return PFN_PHYS(pfn);