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[73.25.156.94]) by smtp.gmail.com with ESMTPSA id q18sm3629863pfh.170.2021.09.30.11.20.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Sep 2021 11:20:32 -0700 (PDT) From: Rob Clark To: dri-devel@lists.freedesktop.org Cc: freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, Jordan Crouse , Rob Clark , Rob Clark , Sean Paul , David Airlie , Daniel Vetter , Akhil P Oommen , Jonathan Marek , Dmitry Baryshkov , Sharat Masetty , Douglas Anderson , Sai Prakash Ranjan , Yangtao Li , linux-kernel@vger.kernel.org (open list) Subject: [PATCH] drm/msm/a6xx: Track current ctx by seqno Date: Thu, 30 Sep 2021 11:25:02 -0700 Message-Id: <20210930182506.1236811-1-robdclark@gmail.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org From: Rob Clark In theory a context can be destroyed and a new one allocated at the same address, making the pointer comparision to detect when we don't need to update the current pagetables invalid. Instead assign a sequence number to each context on creation, and use this for the check. Fixes: 84c31ee16f90 ("drm/msm/a6xx: Add support for per-instance pagetables") Signed-off-by: Rob Clark --- drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 6 +++--- drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 11 ++++++++++- drivers/gpu/drm/msm/msm_drv.c | 3 +++ drivers/gpu/drm/msm/msm_drv.h | 1 + 4 files changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c index 5e1ae3df42ba..e0a8b2fd1ff0 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -106,7 +106,7 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu, u32 asid; u64 memptr = rbmemptr(ring, ttbr0); - if (ctx == a6xx_gpu->cur_ctx) + if (ctx->seqno == a6xx_gpu->cur_ctx_seqno) return; if (msm_iommu_pagetable_params(ctx->aspace->mmu, &ttbr, &asid)) @@ -139,7 +139,7 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu, OUT_PKT7(ring, CP_EVENT_WRITE, 1); OUT_RING(ring, 0x31); - a6xx_gpu->cur_ctx = ctx; + a6xx_gpu->cur_ctx_seqno = ctx->seqno; } static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit) @@ -1081,7 +1081,7 @@ static int hw_init(struct msm_gpu *gpu) /* Always come up on rb 0 */ a6xx_gpu->cur_ring = gpu->rb[0]; - a6xx_gpu->cur_ctx = NULL; + a6xx_gpu->cur_ctx_seqno = 0; /* Enable the SQE_to start the CP engine */ gpu_write(gpu, REG_A6XX_CP_SQE_CNTL, 1); diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h index 0bc2d062f54a..8e5527c881b1 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h @@ -19,7 +19,16 @@ struct a6xx_gpu { uint64_t sqe_iova; struct msm_ringbuffer *cur_ring; - struct msm_file_private *cur_ctx; + + /** + * cur_ctx_seqno: + * + * The ctx->seqno value of the context with current pgtables + * installed. Tracked by seqno rather than pointer value to + * avoid dangling pointers, and cases where a ctx can be freed + * and a new one created with the same address. + */ + int cur_ctx_seqno; struct a6xx_gmu gmu; diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 624078b3adf2..30c1efc3d8a0 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -711,6 +711,7 @@ static void load_gpu(struct drm_device *dev) static int context_init(struct drm_device *dev, struct drm_file *file) { + static atomic_t ident = ATOMIC_INIT(0); struct msm_drm_private *priv = dev->dev_private; struct msm_file_private *ctx; @@ -727,6 +728,8 @@ static int context_init(struct drm_device *dev, struct drm_file *file) ctx->aspace = msm_gpu_create_private_address_space(priv->gpu, current); file->driver_priv = ctx; + ctx->seqno = atomic_inc_return(&ident); + return 0; } diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h index de062450add4..8633d0059a3e 100644 --- a/drivers/gpu/drm/msm/msm_drv.h +++ b/drivers/gpu/drm/msm/msm_drv.h @@ -59,6 +59,7 @@ struct msm_file_private { int queueid; struct msm_gem_address_space *aspace; struct kref ref; + int seqno; }; enum msm_mdp_plane_property {