drm/i915: Limit page allocations to lowmem (dma32) for i965

Broadwater and Crestline share a limitation that prevent it from
relocating general surface state above 4GiB. The only recourse we have
since any buffer object may be used as a relocation target is then to
limit all object allocations on 965g[m] to DMA32.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem.c

@@ -3263,6 +3263,7 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
 	struct address_space *mapping;
+	u32 mask;
 
 	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
 	if (obj == NULL)
@@ -3273,8 +3274,15 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 		return NULL;
 	}
 
+	mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
+	if (IS_CRESTLINE(dev) || IS_BROADWATER(dev)) {
+		/* 965gm cannot relocate objects above 4GiB. */
+		mask &= ~__GFP_HIGHMEM;
+		mask |= __GFP_DMA32;
+	}
+
 	mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping;
-	mapping_set_gfp_mask(mapping, GFP_HIGHUSER | __GFP_RECLAIMABLE);
+	mapping_set_gfp_mask(mapping, mask);
 
 	i915_gem_info_add_obj(dev_priv, size);