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Commit 355a7018 authored by Thomas Hellstrom's avatar Thomas Hellstrom Committed by Dave Airlie
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drm/gem: Warn on illegal use of the dumb buffer interface v2 



It happens on occasion that developers of generic user-space applications
abuse the dumb buffer API to get hold of drm buffers that they can both
mmap() and use for GPU acceleration, using the assumptions that dumb buffers
and buffers available for GPU are
a) The same type and can be aribtrarily type-casted.
b) fully coherent.

This patch makes the most widely used drivers warn nicely when that happens,
the next step will be to fail.

v2: Move drmP.h changes to drm_gem.h. Fix Radeon dumb mmap breakage.

Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent cc5ac1ca

drivers/gpu/drm/i915/i915_drv.c

+1 −1
Original line number Diff line number Diff line
@@ -1593,7 +1593,7 @@ static struct drm_driver driver = { 
	.gem_prime_import = i915_gem_prime_import,



	.dumb_create = i915_gem_dumb_create,

	.dumb_map_offset = i915_gem_mmap_gtt,

	.dumb_map_offset = i915_gem_dumb_map_offset,

	.dumb_destroy = drm_gem_dumb_destroy,

	.ioctls = i915_ioctls,

	.fops = &i915_driver_fops,

drivers/gpu/drm/i915/i915_drv.h

+3 −2
Original line number Diff line number Diff line
@@ -2523,8 +2523,9 @@ void i915_vma_move_to_active(struct i915_vma *vma, 
int i915_gem_dumb_create(struct drm_file *file_priv,

			 struct drm_device *dev,

			 struct drm_mode_create_dumb *args);

int i915_gem_mmap_gtt(struct drm_file *file_priv, struct drm_device *dev,

		      uint32_t handle, uint64_t *offset);

int i915_gem_dumb_map_offset(struct drm_file *file_priv,

			     struct drm_device *dev, uint32_t handle,

			     uint64_t *offset);

/**

 * Returns true if seq1 is later than seq2.

 */

drivers/gpu/drm/i915/i915_gem.c

+23 −5
Original line number Diff line number Diff line
@@ -346,6 +346,7 @@ static int 
i915_gem_create(struct drm_file *file,

		struct drm_device *dev,

		uint64_t size,

		bool dumb,

		uint32_t *handle_p)

{

	struct drm_i915_gem_object *obj;
@@ -361,6 +362,7 @@ i915_gem_create(struct drm_file *file, 
	if (obj == NULL)

		return -ENOMEM;



	obj->base.dumb = dumb;

	ret = drm_gem_handle_create(file, &obj->base, &handle);

	/* drop reference from allocate - handle holds it now */

	drm_gem_object_unreference_unlocked(&obj->base);
@@ -380,7 +382,7 @@ i915_gem_dumb_create(struct drm_file *file, 
	args->pitch = ALIGN(args->width * DIV_ROUND_UP(args->bpp, 8), 64);

	args->size = args->pitch * args->height;

	return i915_gem_create(file, dev,

			       args->size, &args->handle);

			       args->size, true, &args->handle);

}



/**
@@ -393,7 +395,7 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data, 
	struct drm_i915_gem_create *args = data;



	return i915_gem_create(file, dev,

			       args->size, &args->handle);

			       args->size, false, &args->handle);

}



static inline int
@@ -1773,10 +1775,10 @@ static void i915_gem_object_free_mmap_offset(struct drm_i915_gem_object *obj) 
	drm_gem_free_mmap_offset(&obj->base);

}



int

static int

i915_gem_mmap_gtt(struct drm_file *file,

		  struct drm_device *dev,

		  uint32_t handle,

		  uint32_t handle, bool dumb,

		  uint64_t *offset)

{

	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1793,6 +1795,13 @@ i915_gem_mmap_gtt(struct drm_file *file, 
		goto unlock;

	}



	/*

	 * We don't allow dumb mmaps on objects created using another

	 * interface.

	 */

	WARN_ONCE(dumb && !(obj->base.dumb || obj->base.import_attach),

		  "Illegal dumb map of accelerated buffer.\n");



	if (obj->base.size > dev_priv->gtt.mappable_end) {

		ret = -E2BIG;

		goto out;
@@ -1817,6 +1826,15 @@ i915_gem_mmap_gtt(struct drm_file *file, 
	return ret;

}



int

i915_gem_dumb_map_offset(struct drm_file *file,

			 struct drm_device *dev,

			 uint32_t handle,

			 uint64_t *offset)

{

	return i915_gem_mmap_gtt(file, dev, handle, true, offset);

}



/**

 * i915_gem_mmap_gtt_ioctl - prepare an object for GTT mmap'ing

 * @dev: DRM device
@@ -1838,7 +1856,7 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data, 
{

	struct drm_i915_gem_mmap_gtt *args = data;



	return i915_gem_mmap_gtt(file, dev, args->handle, &args->offset);

	return i915_gem_mmap_gtt(file, dev, args->handle, false, &args->offset);

}



static inline int

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+3 −0
Original line number Diff line number Diff line
@@ -121,6 +121,9 @@ eb_lookup_vmas(struct eb_vmas *eb, 
			goto err;

		}



		WARN_ONCE(obj->base.dumb,

			  "GPU use of dumb buffer is illegal.\n");



		drm_gem_object_reference(&obj->base);

		list_add_tail(&obj->obj_exec_link, &objects);

	}

drivers/gpu/drm/nouveau/nouveau_display.c

+9 −0
Original line number Diff line number Diff line
@@ -871,6 +871,7 @@ nouveau_display_dumb_create(struct drm_file *file_priv, struct drm_device *dev, 
	if (ret)

		return ret;



	bo->gem.dumb = true;

	ret = drm_gem_handle_create(file_priv, &bo->gem, &args->handle);

	drm_gem_object_unreference_unlocked(&bo->gem);

	return ret;
@@ -886,6 +887,14 @@ nouveau_display_dumb_map_offset(struct drm_file *file_priv, 
	gem = drm_gem_object_lookup(dev, file_priv, handle);

	if (gem) {

		struct nouveau_bo *bo = nouveau_gem_object(gem);



		/*

		 * We don't allow dumb mmaps on objects created using another

		 * interface.

		 */

		WARN_ONCE(!(gem->dumb || gem->import_attach),

			  "Illegal dumb map of accelerated buffer.\n");



		*poffset = drm_vma_node_offset_addr(&bo->bo.vma_node);

		drm_gem_object_unreference_unlocked(gem);

		return 0;