gpu: nvgpu: cde: Map backing store as read-only

The cde shader will only read data from the global compbit backing
store. Map it as read-only to enforce this.

Change-Id: If5be44b8daedd5e7fdee650a6e76befa7bdecfd6
Signed-off-by: Lauri Peltonen <lpeltonen@nvidia.com>
Reviewed-on: http://git-master/r/486679

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/cde_gk20a.c b/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
index 57707f54..24e2a778 100644
--- a/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
@@ -795,7 +795,7 @@ int gk20a_cde_load(struct gk20a_cde_ctx *cde_ctx)
         /* map backing store to gpu virtual space */
         vaddr = gk20a_gmmu_map(ch->vm, &gr->compbit_store.sgt,
                                g->gr.compbit_store.size, 0,
-                               gk20a_mem_flag_none);
+                               gk20a_mem_flag_read_only);
 
         if (!vaddr) {
                 gk20a_warn(&cde_ctx->pdev->dev, "cde: cannot map compression bit backing store");