drm/i915: Reject unknown syncobj flags

We have to reject unknown flags for uAPI considerations, and also
because the curent implementation limits their i915 storage space
to two bits.

v2: (Chris Wilson)
 * Fix fail in ABI check.
 * Added unknown flags and BUILD_BUG_ON.

v3:
 * Use ARCH_KMALLOC_MINALIGN instead of alignof. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <[email protected]>
Fixes: cf6e7bac6357 ("drm/i915: Add support for drm syncobjs")
Cc: Jason Ekstrand <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: David Airlie <[email protected]>
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Chris Wilson <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit ebcaa1ff8b59097805d548fe7a676f194625c033)
Signed-off-by: Rodrigo Vivi <[email protected]>

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 4ac454ae54d73068ef3b79b673ad0c7c0e4e00cc..83876a1c8d98b86037d50f6f007af7fa722c2652 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -2094,6 +2094,11 @@ get_fence_array(struct drm_i915_gem_execbuffer2 *args,
                        goto err;
                }
 
+               if (fence.flags & __I915_EXEC_FENCE_UNKNOWN_FLAGS) {
+                       err = -EINVAL;
+                       goto err;
+               }
+
                syncobj = drm_syncobj_find(file, fence.handle);
                if (!syncobj) {
                        DRM_DEBUG("Invalid syncobj handle provided\n");
@@ -2101,6 +2106,9 @@ get_fence_array(struct drm_i915_gem_execbuffer2 *args,
                        goto err;
                }
 
+               BUILD_BUG_ON(~(ARCH_KMALLOC_MINALIGN - 1) &
+                            ~__I915_EXEC_FENCE_UNKNOWN_FLAGS);
+
                fences[n] = ptr_pack_bits(syncobj, fence.flags, 2);
        }
 

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 6598fb76d2c27741d2c916f914b70c5f472911f9..9816590d3ad24b0d7037eb65f9b84c3c571c9b53 100644 (file)
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -829,6 +829,7 @@ struct drm_i915_gem_exec_fence {
 
 #define I915_EXEC_FENCE_WAIT            (1<<0)
 #define I915_EXEC_FENCE_SIGNAL          (1<<1)
+#define __I915_EXEC_FENCE_UNKNOWN_FLAGS (-(I915_EXEC_FENCE_SIGNAL << 1))
        __u32 flags;
 };