[PATCH 1/2] accel/ethosu: reject NPU_OP_RESIZE commands from userspace

[Muhammad Bilal <meatuni001@gmail.com>]

NPU_OP_RESIZE is a U85-only command that the driver does not yet
implement. The existing WARN_ON(1) placeholder fires unconditionally
whenever userspace submits this command via DRM_IOCTL_ETHOSU_GEM_CREATE,
causing unbounded kernel log spam.

If panic_on_warn is set the kernel panics, giving any unprivileged user
with access to the DRM device a trivial denial-of-service primitive.

Replace the WARN_ON(1) with an explicit -EINVAL return so the ioctl
rejects the command before it reaches hardware.

Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
---
 drivers/accel/ethosu/ethosu_gem.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/accel/ethosu/ethosu_gem.c b/drivers/accel/ethosu/ethosu_gem.c
index 80d4bc21c28f..043541407a8f 100644
--- a/drivers/accel/ethosu/ethosu_gem.c
+++ b/drivers/accel/ethosu/ethosu_gem.c
@@ -433,8 +433,7 @@ static int ethosu_gem_cmdstream_copy_and_validate(struct drm_device *ddev,
 				return ret;
 			break;
 		case NPU_OP_RESIZE: // U85 only
-			WARN_ON(1); // TODO
-			break;
+			return -EINVAL;
 		case NPU_SET_KERNEL_WIDTH_M1:
 			st.ifm.width = param;
 			break;
-- 
2.53.0