[PATCH] drm/kmb: Avoid warnings on impossible plane_id
Kees Cook
keescook at chromium.org
Wed Aug 25 18:18:07 UTC 2021
KMB_MAX_PLANES is defined as 1, yet kmb_plane_atomic_disable() had code
for writing beyond 1. It is gated by a WARN_ON() that would skip it,
though, but under some compiler versions, poor Dead Code Elimination
wasn't optimizing away the unused switch cases, leading to array bounds
warnings when building with -Warray-bounds:
drivers/gpu/drm/kmb/kmb_plane.c:135:20: warning: array subscript 3 is above array bounds of 'struct layer_status[1]' [-Warray-bounds]
drivers/gpu/drm/kmb/kmb_plane.c:132:20: warning: array subscript 2 is above array bounds of 'struct layer_status[1]' [-Warray-bounds]
drivers/gpu/drm/kmb/kmb_plane.c:129:20: warning: array subscript 1 is above array bounds of 'struct layer_status[1]' [-Warray-bounds]
Instead, just remove the switch statement entirely and adjust the index
type to match the struct "id" member.
Cc: Anitha Chrisanthus <anitha.chrisanthus at intel.com>
Cc: Edmund Dea <edmund.j.dea at intel.com>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: dri-devel at lists.freedesktop.org
Fixes: 7f7b96a8a0a1 ("drm/kmb: Add support for KeemBay Display")
Signed-off-by: Kees Cook <keescook at chromium.org>
---
drivers/gpu/drm/kmb/kmb_plane.c | 18 ++----------------
1 file changed, 2 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/kmb/kmb_plane.c b/drivers/gpu/drm/kmb/kmb_plane.c
index ecee6782612d..3d46e756f2fe 100644
--- a/drivers/gpu/drm/kmb/kmb_plane.c
+++ b/drivers/gpu/drm/kmb/kmb_plane.c
@@ -113,7 +113,7 @@ static void kmb_plane_atomic_disable(struct drm_plane *plane,
struct drm_atomic_state *state)
{
struct kmb_plane *kmb_plane = to_kmb_plane(plane);
- int plane_id = kmb_plane->id;
+ unsigned char plane_id = kmb_plane->id;
struct kmb_drm_private *kmb;
kmb = to_kmb(plane->dev);
@@ -121,21 +121,7 @@ static void kmb_plane_atomic_disable(struct drm_plane *plane,
if (WARN_ON(plane_id >= KMB_MAX_PLANES))
return;
- switch (plane_id) {
- case LAYER_0:
- kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL1_ENABLE;
- break;
- case LAYER_1:
- kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL2_ENABLE;
- break;
- case LAYER_2:
- kmb->plane_status[plane_id].ctrl = LCD_CTRL_GL1_ENABLE;
- break;
- case LAYER_3:
- kmb->plane_status[plane_id].ctrl = LCD_CTRL_GL2_ENABLE;
- break;
- }
-
+ kmb->plane_status[plane_id].ctrl = LCD_CTRL_VL1_ENABLE;
kmb->plane_status[plane_id].disable = true;
}
--
2.30.2
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