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From:   Jordan Crouse <jcrouse@codeaurora.org>
To:     linux-arm-msm@vger.kernel.org
Cc:     Robin Murphy <robin.murphy@arm.com>, Will Deacon <will@kernel.org>,
        iommu@lists.linux-foundation.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joerg Roedel <joro@8bytes.org>,
        Krishna Reddy <vdumpa@nvidia.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH v1 1/3] iommu/arm-smmu: Add support for driver IOMMU fault handlers
Date:   Mon,  9 Nov 2020 15:23:17 -0700
Message-Id: <20201109222319.2630557-2-jcrouse@codeaurora.org>
In-Reply-To: <20201109222319.2630557-1-jcrouse@codeaurora.org>
References: <20201109222319.2630557-1-jcrouse@codeaurora.org>
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Call report_iommu_fault() to allow upper-level drivers to register their
own fault handlers.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

 drivers/iommu/arm/arm-smmu/arm-smmu.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 0f28a8614da3..7fd18bbda8f5 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -427,6 +427,7 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	int idx = smmu_domain->cfg.cbndx;
+	int ret;
 
 	fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
 	if (!(fsr & ARM_SMMU_FSR_FAULT))
@@ -436,11 +437,20 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 	iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR);
 	cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx));
 
-	dev_err_ratelimited(smmu->dev,
-	"Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
+	ret = report_iommu_fault(domain, dev, iova,
+		fsynr & ARM_SMMU_FSYNR0_WNR ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ);
+
+	if (ret == -ENOSYS)
+		dev_err_ratelimited(smmu->dev,
+		"Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
 			    fsr, iova, fsynr, cbfrsynra, idx);
 
-	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr);
+	/*
+	 * If the iommu fault returns an error (except -ENOSYS) then assume that
+	 * they will handle resuming on their own
+	 */
+	if (!ret || ret == -ENOSYS)
+		arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr);
 	return IRQ_HANDLED;
 }
 
-- 
2.25.1