Patch "iommu/arm-smmu: Don't BUG() if we find aborting STEs with disable_bypass" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    iommu/arm-smmu: Don't BUG() if we find aborting STEs with disable_bypass

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iommu-arm-smmu-don-t-bug-if-we-find-aborting-stes-with-disable_bypass.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 5bc0a11664e17e9f9551983f5b660bd48b57483c Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Tue, 16 Aug 2016 14:29:16 +0100
Subject: iommu/arm-smmu: Don't BUG() if we find aborting STEs with disable_bypass

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 */
 		}


Patches currently in stable-queue which might be from will.deacon@arm.com are

queue-4.4/arm64-define-at_vector_size_arch-for-arch_dlinfo.patch
queue-4.4/iommu-arm-smmu-don-t-bug-if-we-find-aborting-stes-with-disable_bypass.patch
queue-4.4/iommu-arm-smmu-fix-cmdq-error-handling.patch