Commit e633fc7a authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon

iommu/io-pgtable-arm-v7s: Fix attributes when splitting blocks

Due to the attribute bits being all over the place in the different
types of short-descriptor PTEs, when remapping an existing entry, e.g.
splitting a section into pages, we take the approach of decomposing
the PTE attributes back to the IOMMU API flags to start from scratch.

On inspection, though, the existing code seems to have got the read-only
bit backwards and ignored the XN bit. How embarrassing...

Fortunately the primary user so far, the Mediatek IOMMU, both never
splits blocks (because it only serves non-overlapping DMA API calls) and
also ignores permissions anyway, but let's put things right before any
future users trip up.

Cc: <stable@vger.kernel.org>
Fixes: e5fc9753 ("iommu/io-pgtable: Add ARMv7 short descriptor support")
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 694d0d0b
...@@ -286,12 +286,14 @@ static int arm_v7s_pte_to_prot(arm_v7s_iopte pte, int lvl) ...@@ -286,12 +286,14 @@ static int arm_v7s_pte_to_prot(arm_v7s_iopte pte, int lvl)
int prot = IOMMU_READ; int prot = IOMMU_READ;
arm_v7s_iopte attr = pte >> ARM_V7S_ATTR_SHIFT(lvl); arm_v7s_iopte attr = pte >> ARM_V7S_ATTR_SHIFT(lvl);
if (attr & ARM_V7S_PTE_AP_RDONLY) if (!(attr & ARM_V7S_PTE_AP_RDONLY))
prot |= IOMMU_WRITE; prot |= IOMMU_WRITE;
if ((attr & (ARM_V7S_TEX_MASK << ARM_V7S_TEX_SHIFT)) == 0) if ((attr & (ARM_V7S_TEX_MASK << ARM_V7S_TEX_SHIFT)) == 0)
prot |= IOMMU_MMIO; prot |= IOMMU_MMIO;
else if (pte & ARM_V7S_ATTR_C) else if (pte & ARM_V7S_ATTR_C)
prot |= IOMMU_CACHE; prot |= IOMMU_CACHE;
if (pte & ARM_V7S_ATTR_XN(lvl))
prot |= IOMMU_NOEXEC;
return prot; return prot;
} }
......
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