[PATCH 4.4 056/113] iommu/arm-smmu: Dont BUG() if we find aborting STEs with disable_bypass

Greg Kroah-Hartman
2016-09-05T17:14:22Z

From: Will Deacon <will.deacon@arm.com>

commit 5bc0a11664e17e9f9551983f5b660bd48b57483c upstream.

The disable_bypass cmdline option changes the SMMUv3 driver to put down
faulting stream table entries by default, as opposed to bypassing
transactions from unconfigured devices.

In this mode of operation, it is entirely expected to see aborting
entries in the stream table if and when we come to installing a valid
translation, so don't trigger a BUG() as a result of misdiagnosing these
entries as stream table corruption.

Fixes: 48ec83bcbcf5 ("iommu/arm-smmu: Add initial driver support for ARM SMMUv3 devices")
Tested-by: Robin Murphy <robin.murphy@arm.com>
Reported-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/iommu/arm-smmu-v3.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1025,6 +1025,9 @@ static void arm_smmu_write_strtab_ent(st
case STRTAB_STE_0_CFG_S2_TRANS:
ste_live = true;
break;
+ case STRTAB_STE_0_CFG_ABORT:
+ if (disable_bypass)
+ break;
default:
BUG(); /* STE corruption */
}