releases/4.3.5/iommu-arm-smmu-fix-error-checking-for-asid-and-vmid-allocation.patch

From c0733a2cf30c1e7923b6ad4f8df67941502923de Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Tue, 13 Oct 2015 17:51:14 +0100
Subject: iommu/arm-smmu: Fix error checking for ASID and VMID allocation

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

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@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iommu/arm-smmu-v3.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1427,7 +1427,7 @@ static int arm_smmu_domain_finalise_s1(s
 				       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;
 
@@ -1439,10 +1439,11 @@ static int arm_smmu_domain_finalise_s1(s
 					 &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];
@@ -1456,7 +1457,7 @@ 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;
 
@@ -1464,7 +1465,7 @@ static int arm_smmu_domain_finalise_s2(s
 	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;