linux-kernel - [PATCH 5.5 141/189] drm/panfrost: Dont try to map on error faults

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Date:   Tue, 10 Mar 2020 13:39:38 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Steven Price <steven.price@....com>,
        Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>
Subject: [PATCH 5.5 141/189] drm/panfrost: Dont try to map on error faults

From: Tomeu Vizoso <tomeu.vizoso@...labora.com>

commit eb9d8ddbc107d02e489681f9dcbf93949e1a99a4 upstream.

If the exception type isn't a translation fault, don't try to map and
instead go straight to a terminal fault.

Otherwise, we can get flooded by kernel warnings and further faults.

Fixes: 187d2929206e ("drm/panfrost: Add support for GPU heap allocations")
Signed-off-by: Rob Herring <robh@...nel.org>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
Reviewed-by: Steven Price <steven.price@....com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200212202236.13095-1-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/panfrost/panfrost_mmu.c |   44 +++++++++++++-------------------
 1 file changed, 19 insertions(+), 25 deletions(-)

--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -601,33 +601,27 @@ static irqreturn_t panfrost_mmu_irq_hand
 		source_id = (fault_status >> 16);
 
 		/* Page fault only */
-		if ((status & mask) == BIT(i)) {
-			WARN_ON(exception_type < 0xC1 || exception_type > 0xC4);
-
+		ret = -1;
+		if ((status & mask) == BIT(i) && (exception_type & 0xF8) == 0xC0)
 			ret = panfrost_mmu_map_fault_addr(pfdev, i, addr);
-			if (!ret) {
-				mmu_write(pfdev, MMU_INT_CLEAR, BIT(i));
-				status &= ~mask;
-				continue;
-			}
-		}
 
-		/* terminal fault, print info about the fault */
-		dev_err(pfdev->dev,
-			"Unhandled Page fault in AS%d at VA 0x%016llX\n"
-			"Reason: %s\n"
-			"raw fault status: 0x%X\n"
-			"decoded fault status: %s\n"
-			"exception type 0x%X: %s\n"
-			"access type 0x%X: %s\n"
-			"source id 0x%X\n",
-			i, addr,
-			"TODO",
-			fault_status,
-			(fault_status & (1 << 10) ? "DECODER FAULT" : "SLAVE FAULT"),
-			exception_type, panfrost_exception_name(pfdev, exception_type),
-			access_type, access_type_name(pfdev, fault_status),
-			source_id);
+		if (ret)
+			/* terminal fault, print info about the fault */
+			dev_err(pfdev->dev,
+				"Unhandled Page fault in AS%d at VA 0x%016llX\n"
+				"Reason: %s\n"
+				"raw fault status: 0x%X\n"
+				"decoded fault status: %s\n"
+				"exception type 0x%X: %s\n"
+				"access type 0x%X: %s\n"
+				"source id 0x%X\n",
+				i, addr,
+				"TODO",
+				fault_status,
+				(fault_status & (1 << 10) ? "DECODER FAULT" : "SLAVE FAULT"),
+				exception_type, panfrost_exception_name(pfdev, exception_type),
+				access_type, access_type_name(pfdev, fault_status),
+				source_id);
 
 		mmu_write(pfdev, MMU_INT_CLEAR, mask);