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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will.deacon@arm.com>
Subject: [PATCH 4.19 290/361] iommu/arm-smmu: Ensure that page-table updates are visible before TLBI
Date:   Sun, 11 Nov 2018 14:20:37 -0800
Message-Id: <20181111221656.614720724@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

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

commit 7d321bd3542500caf125249f44dc37cb4e738013 upstream.

The IO-pgtable code relies on the driver TLB invalidation callbacks to
ensure that all page-table updates are visible to the IOMMU page-table
walker.

In the case that the page-table walker is cache-coherent, we cannot rely
on an implicit DSB from the DMA-mapping code, so we must ensure that we
execute a DSB in our tlb_add_flush() callback prior to triggering the
invalidation.

Cc: <stable@vger.kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Fixes: 2df7a25ce4a7 ("iommu/arm-smmu: Clean up DMA API usage")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iommu/arm-smmu.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -469,6 +469,9 @@ static void arm_smmu_tlb_inv_range_nosyn
 	bool stage1 = cfg->cbar != CBAR_TYPE_S2_TRANS;
 	void __iomem *reg = ARM_SMMU_CB(smmu_domain->smmu, cfg->cbndx);
 
+	if (smmu_domain->smmu->features & ARM_SMMU_FEAT_COHERENT_WALK)
+		wmb();
+
 	if (stage1) {
 		reg += leaf ? ARM_SMMU_CB_S1_TLBIVAL : ARM_SMMU_CB_S1_TLBIVA;
 
@@ -510,6 +513,9 @@ static void arm_smmu_tlb_inv_vmid_nosync
 	struct arm_smmu_domain *smmu_domain = cookie;
 	void __iomem *base = ARM_SMMU_GR0(smmu_domain->smmu);
 
+	if (smmu_domain->smmu->features & ARM_SMMU_FEAT_COHERENT_WALK)
+		wmb();
+
 	writel_relaxed(smmu_domain->cfg.vmid, base + ARM_SMMU_GR0_TLBIVMID);
 }