[PATCH 3/7] drm/amd/display: Avoid using unvalidated tiling_flags and tmz_surface in prepare_planes

[Rodrigo Siqueira]

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>

On 07/30, Nicholas Kazlauskas wrote:
> [Why]
> We're racing with userspace as the flags could potentially change
> from when we acquired and validated them in commit_check.
> 
> [How]
> We unfortunately can't drop this function in its entirety from
> prepare_planes since we don't know the afb->address at commit_check
> time yet.
> 
> So instead of querying new tiling_flags and tmz_surface use the ones
> from the plane_state directly.
> 
> While we're at it, also update the force_disable_dcc option based
> on the state from atomic check.
> 
> Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
> Cc: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> ---
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 36 ++++++++++---------
>  1 file changed, 19 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index bf1881bd492c..f78c09c9585e 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -5794,14 +5794,8 @@ static int dm_plane_helper_prepare_fb(struct drm_plane *plane,
>  	struct list_head list;
>  	struct ttm_validate_buffer tv;
>  	struct ww_acquire_ctx ticket;
> -	uint64_t tiling_flags;
>  	uint32_t domain;
>  	int r;
> -	bool tmz_surface = false;
> -	bool force_disable_dcc = false;
> -
> -	dm_plane_state_old = to_dm_plane_state(plane->state);
> -	dm_plane_state_new = to_dm_plane_state(new_state);
>  
>  	if (!new_state->fb) {
>  		DRM_DEBUG_DRIVER("No FB bound\n");
> @@ -5845,27 +5839,35 @@ static int dm_plane_helper_prepare_fb(struct drm_plane *plane,
>  		return r;
>  	}
>  
> -	amdgpu_bo_get_tiling_flags(rbo, &tiling_flags);
> -
> -	tmz_surface = amdgpu_bo_encrypted(rbo);
> -
>  	ttm_eu_backoff_reservation(&ticket, &list);
>  
>  	afb->address = amdgpu_bo_gpu_offset(rbo);
>  
>  	amdgpu_bo_ref(rbo);
>  
> +	/**
> +	 * We don't do surface updates on planes that have been newly created,
> +	 * but we also don't have the afb->address during atomic check.
> +	 *
> +	 * Fill in buffer attributes depending on the address here, but only on
> +	 * newly created planes since they're not being used by DC yet and this
> +	 * won't modify global state.
> +	 */
> +	dm_plane_state_old = to_dm_plane_state(plane->state);
> +	dm_plane_state_new = to_dm_plane_state(new_state);
> +
>  	if (dm_plane_state_new->dc_state &&
> -			dm_plane_state_old->dc_state != dm_plane_state_new->dc_state) {
> -		struct dc_plane_state *plane_state = dm_plane_state_new->dc_state;
> +	    dm_plane_state_old->dc_state != dm_plane_state_new->dc_state) {
> +		struct dc_plane_state *plane_state =
> +			dm_plane_state_new->dc_state;
> +		bool force_disable_dcc = !plane_state->dcc.enable;
>  
> -		force_disable_dcc = adev->asic_type == CHIP_RAVEN && adev->in_suspend;
>  		fill_plane_buffer_attributes(
>  			adev, afb, plane_state->format, plane_state->rotation,
> -			tiling_flags, &plane_state->tiling_info,
> -			&plane_state->plane_size, &plane_state->dcc,
> -			&plane_state->address, tmz_surface,
> -			force_disable_dcc);
> +			dm_plane_state_new->tiling_flags,
> +			&plane_state->tiling_info, &plane_state->plane_size,
> +			&plane_state->dcc, &plane_state->address,
> +			dm_plane_state_new->tmz_surface, force_disable_dcc);
>  	}
>  
>  	return 0;
> -- 
> 2.25.1
> 

-- 
Rodrigo Siqueira
https://siqueira.tech
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