[RFC 1/1] SWDEV476969 - dm: Fail dm_atomic_check if cursor overlay is required at MAX_SURFACES

[Zaeem Mohamed]

[why]
Prevent index-out-of-bounds due to requiring cursor overlay when
plane_count is MAX_SURFACES.

[how]
Bounds check on plane_count when requiring overlay cursor.

Co-developed-by: Melissa Wen <m...@igalia.com>
Signed-off-by: Zaeem Mohamed <zaeem.moha...@amd.com>
---
 amdgpu_dm/amdgpu_dm.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/amdgpu_dm/amdgpu_dm.c b/amdgpu_dm/amdgpu_dm.c
index df83e7b42b..c2595efb74 100644
--- a/amdgpu_dm/amdgpu_dm.c
+++ b/amdgpu_dm/amdgpu_dm.c
@@ -11676,6 +11676,12 @@ static int amdgpu_dm_atomic_check(struct drm_device 
*dev,
                 * need to be added for DC to not disable a plane by mistake
                 */
                if (dm_new_crtc_state->cursor_mode == DM_CURSOR_OVERLAY_MODE) {
+                       if(dc->current_state->stream_status->plane_count >= 
MAX_SURFACES){
+                               drm_dbg_driver(crtc->dev,
+                                      "Can't enable cursor plane with %d 
planes\n", MAX_SURFACES);
+                               ret = -EINVAL;
+                               goto fail;
+                       }
                        ret = drm_atomic_add_affected_planes(state, crtc);
                        if (ret)
                                goto fail;
@@ -11769,8 +11775,16 @@ static int amdgpu_dm_atomic_check(struct drm_device 
*dev,
 
                /* Overlay cusor not subject to native cursor restrictions */
                dm_new_crtc_state = to_dm_crtc_state(new_crtc_state);
-               if (dm_new_crtc_state->cursor_mode == DM_CURSOR_OVERLAY_MODE)
+               if (dm_new_crtc_state->cursor_mode == DM_CURSOR_OVERLAY_MODE){
+                       if(dc->current_state->stream_status->plane_count > 
MAX_SURFACES){
+                               drm_dbg_driver(crtc->dev,
+                                      "Can't enable cursor plane with %d 
planes\n", MAX_SURFACES);
+                               ret = -EINVAL;
+                               goto fail;
+                       }
+                       
                        continue;
+               }
 
                /* Check if rotation or scaling is enabled on DCN401 */
                if ((drm_plane_mask(crtc->cursor) & new_crtc_state->plane_mask) 
&&
-- 
2.34.1