[4.2.y-ckt stable] Patch "iommu/arm-smmu: Fix error checking for ASID and VMID allocation" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    iommu/arm-smmu: Fix error checking for ASID and VMID allocation

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 80403e976034e999a627b047f0936cb99ccbec2a Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon at arm.com>
Date: Tue, 13 Oct 2015 17:51:14 +0100
Subject: iommu/arm-smmu: Fix error checking for ASID and VMID allocation

commit c0733a2cf30c1e7923b6ad4f8df67941502923de upstream.

The bitmap allocator returns an int, which is one of the standard
negative values on failure. Rather than assigning this straight to a
u16 (like we do for the ASID and VMID callers), which means that we
won't detect failure correctly, use an int for the purposes of error
checking.

Signed-off-by: Will Deacon <will.deacon at arm.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/iommu/arm-smmu-v3.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index da902ba..97d376a 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1445,7 +1445,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
 	int ret;
-	u16 asid;
+	int asid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;

@@ -1457,10 +1457,11 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 					 &cfg->cdptr_dma, GFP_KERNEL);
 	if (!cfg->cdptr) {
 		dev_warn(smmu->dev, "failed to allocate context descriptor\n");
+		ret = -ENOMEM;
 		goto out_free_asid;
 	}

-	cfg->cd.asid	= asid;
+	cfg->cd.asid	= (u16)asid;
 	cfg->cd.ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
 	cfg->cd.tcr	= pgtbl_cfg->arm_lpae_s1_cfg.tcr;
 	cfg->cd.mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair[0];
@@ -1474,7 +1475,7 @@ out_free_asid:
 static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
-	u16 vmid;
+	int vmid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;

@@ -1482,7 +1483,7 @@ static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
 	if (IS_ERR_VALUE(vmid))
 		return vmid;

-	cfg->vmid	= vmid;
+	cfg->vmid	= (u16)vmid;
 	cfg->vttbr	= pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
 	cfg->vtcr	= pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
 	return 0;
--
1.9.1