[mirror_ubuntu-bionic-kernel.git] / drivers / gpu / drm / drm_dumb_buffers.c

/*
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 * Copyright (c) 2008 Red Hat Inc.
 * Copyright (c) 2016 Intel Corporation
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <drm/drmP.h>
#include <drm/drm_gem.h>

#include "drm_crtc_internal.h"

/**
 * DOC: overview
 *
 * The KMS API doesn't standardize backing storage object creation and leaves it
 * to driver-specific ioctls. Furthermore actually creating a buffer object even
 * for GEM-based drivers is done through a driver-specific ioctl - GEM only has
 * a common userspace interface for sharing and destroying objects. While not an
 * issue for full-fledged graphics stacks that include device-specific userspace
 * components (in libdrm for instance), this limit makes DRM-based early boot
 * graphics unnecessarily complex.
 *
 * Dumb objects partly alleviate the problem by providing a standard API to
 * create dumb buffers suitable for scanout, which can then be used to create
 * KMS frame buffers.
 *
 * To support dumb objects drivers must implement the &drm_driver.dumb_create
 * operation. &drm_driver.dumb_destroy defaults to drm_gem_dumb_destroy() if
 * not set and &drm_driver.dumb_map_offset defaults to
 * drm_gem_dumb_map_offset(). See the callbacks for further details.
 *
 * Note that dumb objects may not be used for gpu acceleration, as has been
 * attempted on some ARM embedded platforms. Such drivers really must have
 * a hardware-specific ioctl to allocate suitable buffer objects.
 */

int drm_mode_create_dumb_ioctl(struct drm_device *dev,
			       void *data, struct drm_file *file_priv)
{
	struct drm_mode_create_dumb *args = data;
	u32 cpp, stride, size;

	if (!dev->driver->dumb_create)
		return -ENOSYS;
	if (!args->width || !args->height || !args->bpp)
		return -EINVAL;

	/* overflow checks for 32bit size calculations */
	if (args->bpp > U32_MAX - 8)
		return -EINVAL;
	cpp = DIV_ROUND_UP(args->bpp, 8);
	if (cpp > U32_MAX / args->width)
		return -EINVAL;
	stride = cpp * args->width;
	if (args->height > U32_MAX / stride)
		return -EINVAL;

	/* test for wrap-around */
	size = args->height * stride;
	if (PAGE_ALIGN(size) == 0)
		return -EINVAL;

	/*
	 * handle, pitch and size are output parameters. Zero them out to
	 * prevent drivers from accidentally using uninitialized data. Since
	 * not all existing userspace is clearing these fields properly we
	 * cannot reject IOCTL with garbage in them.
	 */
	args->handle = 0;
	args->pitch = 0;
	args->size = 0;

	return dev->driver->dumb_create(file_priv, dev, args);
}

/**
 * drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
 * @dev: DRM device
 * @data: ioctl data
 * @file_priv: DRM file info
 *
 * Allocate an offset in the drm device node's address space to be able to
 * memory map a dumb buffer.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
			     void *data, struct drm_file *file_priv)
{
	struct drm_mode_map_dumb *args = data;

	if (!dev->driver->dumb_create)
		return -ENOSYS;

	if (dev->driver->dumb_map_offset)
		return dev->driver->dumb_map_offset(file_priv, dev,
						    args->handle,
						    &args->offset);
	else
		return drm_gem_dumb_map_offset(file_priv, dev, args->handle,
					       &args->offset);
}

int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
				void *data, struct drm_file *file_priv)
{
	struct drm_mode_destroy_dumb *args = data;

	if (!dev->driver->dumb_create)
		return -ENOSYS;

	if (dev->driver->dumb_destroy)
		return dev->driver->dumb_destroy(file_priv, dev, args->handle);
	else
		return drm_gem_dumb_destroy(file_priv, dev, args->handle);
}
Commit	Line	Data
1a02ea43 DV	1	/*
	2	* Copyright (c) 2006-2008 Intel Corporation
	3	* Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
	4	* Copyright (c) 2008 Red Hat Inc.
	5	* Copyright (c) 2016 Intel Corporation
	6	*
	7	* Permission to use, copy, modify, distribute, and sell this software and its
	8	* documentation for any purpose is hereby granted without fee, provided that
	9	* the above copyright notice appear in all copies and that both that copyright
	10	* notice and this permission notice appear in supporting documentation, and
	11	* that the name of the copyright holders not be used in advertising or
	12	* publicity pertaining to distribution of the software without specific,
	13	* written prior permission. The copyright holders make no representations
	14	* about the suitability of this software for any purpose. It is provided "as
	15	* is" without express or implied warranty.
	16	*
	17	* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
	18	* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
	19	* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
	20	* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
	21	* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
	22	* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	23	* OF THIS SOFTWARE.
	24	*/
	25
	26	#include <drm/drmP.h>
0be8d63a	27	#include <drm/drm_gem.h>
1a02ea43 DV	28
	29	#include "drm_crtc_internal.h"
	30
	31	/**
4f93624e	32	* DOC: overview
1a02ea43	33	*
4f93624e DV	34	* The KMS API doesn't standardize backing storage object creation and leaves it
	35	* to driver-specific ioctls. Furthermore actually creating a buffer object even
	36	* for GEM-based drivers is done through a driver-specific ioctl - GEM only has
	37	* a common userspace interface for sharing and destroying objects. While not an
	38	* issue for full-fledged graphics stacks that include device-specific userspace
	39	* components (in libdrm for instance), this limit makes DRM-based early boot
	40	* graphics unnecessarily complex.
1a02ea43	41	*
4f93624e DV	42	* Dumb objects partly alleviate the problem by providing a standard API to
	43	* create dumb buffers suitable for scanout, which can then be used to create
	44	* KMS frame buffers.
1a02ea43	45	*
0be8d63a NT	46	* To support dumb objects drivers must implement the &drm_driver.dumb_create
	47	* operation. &drm_driver.dumb_destroy defaults to drm_gem_dumb_destroy() if
	48	* not set and &drm_driver.dumb_map_offset defaults to
	49	* drm_gem_dumb_map_offset(). See the callbacks for further details.
1a02ea43	50	*
4f93624e DV	51	* Note that dumb objects may not be used for gpu acceleration, as has been
	52	* attempted on some ARM embedded platforms. Such drivers really must have
	53	* a hardware-specific ioctl to allocate suitable buffer objects.
1a02ea43	54	*/
4f93624e	55
1a02ea43 DV	56	int drm_mode_create_dumb_ioctl(struct drm_device *dev,
	57	void data, struct drm_file file_priv)
	58	{
	59	struct drm_mode_create_dumb *args = data;
	60	u32 cpp, stride, size;
	61
	62	if (!dev->driver->dumb_create)
	63	return -ENOSYS;
	64	if (!args->width \|\| !args->height \|\| !args->bpp)
	65	return -EINVAL;
	66
	67	/* overflow checks for 32bit size calculations */
9cf62976 DC	68	if (args->bpp > U32_MAX - 8)
9cf62976 DC	69	return -EINVAL;
1a02ea43	70	cpp = DIV_ROUND_UP(args->bpp, 8);
9cf62976	71	if (cpp > U32_MAX / args->width)
1a02ea43 DV	72	return -EINVAL;
1a02ea43 DV	73	stride = cpp * args->width;
9cf62976	74	if (args->height > U32_MAX / stride)
1a02ea43 DV	75	return -EINVAL;
	76
	77	/* test for wrap-around */
	78	size = args->height * stride;
	79	if (PAGE_ALIGN(size) == 0)
	80	return -EINVAL;
	81
	82	/*
	83	* handle, pitch and size are output parameters. Zero them out to
	84	* prevent drivers from accidentally using uninitialized data. Since
	85	* not all existing userspace is clearing these fields properly we
	86	* cannot reject IOCTL with garbage in them.
	87	*/
	88	args->handle = 0;
	89	args->pitch = 0;
	90	args->size = 0;
	91
	92	return dev->driver->dumb_create(file_priv, dev, args);
	93	}
	94
	95	/**
	96	* drm_mode_mmap_dumb_ioctl - create an mmap offset for a dumb backing storage buffer
	97	* @dev: DRM device
	98	* @data: ioctl data
	99	* @file_priv: DRM file info
	100	*
	101	* Allocate an offset in the drm device node's address space to be able to
	102	* memory map a dumb buffer.
	103	*
	104	* Called by the user via ioctl.
	105	*
	106	* Returns:
	107	* Zero on success, negative errno on failure.
	108	*/
	109	int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
	110	void data, struct drm_file file_priv)
	111	{
	112	struct drm_mode_map_dumb *args = data;
	113
0be8d63a	114	if (!dev->driver->dumb_create)
1a02ea43 DV	115	return -ENOSYS;
1a02ea43 DV	116
0be8d63a NT	117	if (dev->driver->dumb_map_offset)
	118	return dev->driver->dumb_map_offset(file_priv, dev,
	119	args->handle,
	120	&args->offset);
	121	else
	122	return drm_gem_dumb_map_offset(file_priv, dev, args->handle,
	123	&args->offset);
1a02ea43 DV	124	}
1a02ea43 DV	125
1a02ea43 DV	126	int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
	127	void data, struct drm_file file_priv)
	128	{
	129	struct drm_mode_destroy_dumb *args = data;
	130
0be8d63a	131	if (!dev->driver->dumb_create)
1a02ea43 DV	132	return -ENOSYS;
1a02ea43 DV	133
0be8d63a NT	134	if (dev->driver->dumb_destroy)
	135	return dev->driver->dumb_destroy(file_priv, dev, args->handle);
	136	else
	137	return drm_gem_dumb_destroy(file_priv, dev, args->handle);
1a02ea43 DV	138	}
1a02ea43 DV	139