linux-kernel - [PATCH 5.8 143/177] drm/msm: Split the a5xx preemption record

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Message-Id: <20200915140700.512752244@linuxfoundation.org>
Date:   Tue, 15 Sep 2020 16:13:34 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...omium.org>
Subject: [PATCH 5.8 143/177] drm/msm: Split the a5xx preemption record

From: Jordan Crouse <jcrouse@...eaurora.org>

commit 34221545d2069dc947131f42392fd4cebabe1b39 upstream.

The main a5xx preemption record can be marked as privileged to
protect it from user access but the counters storage needs to be
remain unprivileged. Split the buffers and mark the critical memory
as privileged.

Cc: stable@...r.kernel.org
Signed-off-by: Jordan Crouse <jcrouse@...eaurora.org>
Signed-off-by: Rob Clark <robdclark@...omium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.h     |    1 +
 drivers/gpu/drm/msm/adreno/a5xx_preempt.c |   25 ++++++++++++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.h
@@ -31,6 +31,7 @@ struct a5xx_gpu {
 	struct msm_ringbuffer *next_ring;
 
 	struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
+	struct drm_gem_object *preempt_counters_bo[MSM_GPU_MAX_RINGS];
 	struct a5xx_preempt_record *preempt[MSM_GPU_MAX_RINGS];
 	uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
 
--- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
@@ -226,19 +226,31 @@ static int preempt_init_ring(struct a5xx
 	struct adreno_gpu *adreno_gpu = &a5xx_gpu->base;
 	struct msm_gpu *gpu = &adreno_gpu->base;
 	struct a5xx_preempt_record *ptr;
-	struct drm_gem_object *bo = NULL;
-	u64 iova = 0;
+	void *counters;
+	struct drm_gem_object *bo = NULL, *counters_bo = NULL;
+	u64 iova = 0, counters_iova = 0;
 
 	ptr = msm_gem_kernel_new(gpu->dev,
 		A5XX_PREEMPT_RECORD_SIZE + A5XX_PREEMPT_COUNTER_SIZE,
-		MSM_BO_UNCACHED, gpu->aspace, &bo, &iova);
+		MSM_BO_UNCACHED | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
 
 	if (IS_ERR(ptr))
 		return PTR_ERR(ptr);
 
+	/* The buffer to store counters needs to be unprivileged */
+	counters = msm_gem_kernel_new(gpu->dev,
+		A5XX_PREEMPT_COUNTER_SIZE,
+		MSM_BO_UNCACHED, gpu->aspace, &counters_bo, &counters_iova);
+	if (IS_ERR(counters)) {
+		msm_gem_kernel_put(bo, gpu->aspace, true);
+		return PTR_ERR(counters);
+	}
+
 	msm_gem_object_set_name(bo, "preempt");
+	msm_gem_object_set_name(counters_bo, "preempt_counters");
 
 	a5xx_gpu->preempt_bo[ring->id] = bo;
+	a5xx_gpu->preempt_counters_bo[ring->id] = counters_bo;
 	a5xx_gpu->preempt_iova[ring->id] = iova;
 	a5xx_gpu->preempt[ring->id] = ptr;
 
@@ -249,7 +261,7 @@ static int preempt_init_ring(struct a5xx
 	ptr->data = 0;
 	ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
 	ptr->rptr_addr = rbmemptr(ring, rptr);
-	ptr->counter = iova + A5XX_PREEMPT_RECORD_SIZE;
+	ptr->counter = counters_iova;
 
 	return 0;
 }
@@ -260,8 +272,11 @@ void a5xx_preempt_fini(struct msm_gpu *g
 	struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
 	int i;
 
-	for (i = 0; i < gpu->nr_rings; i++)
+	for (i = 0; i < gpu->nr_rings; i++) {
 		msm_gem_kernel_put(a5xx_gpu->preempt_bo[i], gpu->aspace, true);
+		msm_gem_kernel_put(a5xx_gpu->preempt_counters_bo[i],
+			gpu->aspace, true);
+	}
 }
 
 void a5xx_preempt_init(struct msm_gpu *gpu)