linux-kernel - [PATCH] iommu: qcom: wire up fault handler

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Message-Id: <20171025152543.1202-1-robdclark@gmail.com>
Date:   Wed, 25 Oct 2017 11:25:34 -0400
From:   Rob Clark <robdclark@...il.com>
To:     iommu@...ts.linux-foundation.org
Cc:     linux-arm-msm@...r.kernel.org, Rob Clark <robdclark@...il.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org
Subject: [PATCH] iommu: qcom: wire up fault handler

This is quite useful for debugging.  Currently, always TERMINATE the
translation when the fault handler returns (since this is all we need
for debugging drivers).  But I expect the SVM work should eventually
let us do something more clever.

Signed-off-by: Rob Clark <robdclark@...il.com>
---
 drivers/iommu/qcom_iommu.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
index c8a587d034b0..3c6866d94e64 100644
--- a/drivers/iommu/qcom_iommu.c
+++ b/drivers/iommu/qcom_iommu.c
@@ -66,6 +66,7 @@ struct qcom_iommu_ctx {
 	void __iomem		*base;
 	bool			 secure_init;
 	u8			 asid;      /* asid and ctx bank # are 1:1 */
+	struct iommu_domain	*domain;
 };
 
 struct qcom_iommu_domain {
@@ -194,12 +195,15 @@ static irqreturn_t qcom_iommu_fault(int irq, void *dev)
 	fsynr = iommu_readl(ctx, ARM_SMMU_CB_FSYNR0);
 	iova = iommu_readq(ctx, ARM_SMMU_CB_FAR);
 
-	dev_err_ratelimited(ctx->dev,
-			    "Unhandled context fault: fsr=0x%x, "
-			    "iova=0x%016llx, fsynr=0x%x, cb=%d\n",
-			    fsr, iova, fsynr, ctx->asid);
+	if (!report_iommu_fault(ctx->domain, ctx->dev, iova, 0)) {
+		dev_err_ratelimited(ctx->dev,
+				    "Unhandled context fault: fsr=0x%x, "
+				    "iova=0x%016llx, fsynr=0x%x, cb=%d\n",
+				    fsr, iova, fsynr, ctx->asid);
+	}
 
 	iommu_writel(ctx, ARM_SMMU_CB_FSR, fsr);
+	iommu_writel(ctx, ARM_SMMU_CB_RESUME, RESUME_TERMINATE);
 
 	return IRQ_HANDLED;
 }
@@ -280,6 +284,8 @@ static int qcom_iommu_init_domain(struct iommu_domain *domain,
 			reg |= SCTLR_E;
 
 		iommu_writel(ctx, ARM_SMMU_CB_SCTLR, reg);
+
+		ctx->domain = domain;
 	}
 
 	mutex_unlock(&qcom_domain->init_mutex);
@@ -395,6 +401,8 @@ static void qcom_iommu_detach_dev(struct iommu_domain *domain, struct device *de
 
 		/* Disable the context bank: */
 		iommu_writel(ctx, ARM_SMMU_CB_SCTLR, 0);
+
+		ctx->domain = NULL;
 	}
 	pm_runtime_put_sync(qcom_iommu->dev);
 
-- 
2.13.6