drm/amdgpu: Prevent race between late signaled fences and GPU reset.

Problem:
After we start handling timed out jobs we assume there fences won't be
signaled but we cannot be sure and sometimes they fire late. We need
to prevent concurrent accesses to fence array from
amdgpu_fence_driver_clear_job_fences during GPU reset and amdgpu_fence_process
from a late EOP interrupt.

Fix:
Before accessing fence array in GPU disable EOP interrupt and flush
all pending interrupt handlers for amdgpu device's interrupt line.

v2: Switch from irq_get/put to full enable/disable_irq for amdgpu

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index a9ae3beaa1d3..c1d04ea3c67f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -532,6 +532,24 @@ void amdgpu_fence_driver_hw_fini(struct amdgpu_device *adev)
 	}
 }
 
+/* Will either stop and flush handlers for amdgpu interrupt or reanble it */
+void amdgpu_fence_driver_isr_toggle(struct amdgpu_device *adev, bool stop)
+{
+	int i;
+
+	for (i = 0; i < AMDGPU_MAX_RINGS; i++) {
+		struct amdgpu_ring *ring = adev->rings[i];
+
+		if (!ring || !ring->fence_drv.initialized || !ring->fence_drv.irq_src)
+			continue;
+
+		if (stop)
+			disable_irq(adev->irq.irq);
+		else
+			enable_irq(adev->irq.irq);
+	}
+}
+
 void amdgpu_fence_driver_sw_fini(struct amdgpu_device *adev)
 {
 	unsigned int i, j;