[PATCH 1/3] drm/i915: Reject unknown syncobj flags

[Chris Wilson]

Quoting Tvrtko Ursulin (2017-10-27 14:40:12)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> We have to reject unknown flags for uAPI considerations, and also
> because the curent implementation limits their i915 storage space
> to two bits.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Fixes: cf6e7bac6357 ("drm/i915: Add support for drm syncobjs")
> Cc: Jason Ekstrand <jason at jlekstrand.net>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: David Airlie <airlied at linux.ie>
> Cc: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org
> ---
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 3d7190764f10..3bc723ed6e2f 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -2100,6 +2100,11 @@ get_fence_array(struct drm_i915_gem_execbuffer2 *args,
>                         goto err;
>                 }
>  

Make the test explicit for the abi:

> +               if (fence.flags & ~((typeof(fence.flags))2)) {
s/2/3/!

if (fence.flags & ~(I915_EXEC_FENCE_WAIT | I915_EXEC_FENCE_SIGNAL)) {

> +                       err = -EINVAL;
> +                       goto err;
> +               }
> +

BUILD_BUG_ON((I915_EXEC_FENCE_WAIT | I915_EXEC_FENCE_SIGNAL)) & ~(alignof(void *)-1)) ?

#define I915_EXEC_FENCE_FLAGS ... ?
-Chris