summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/drm_dumb_buffers.c
blob: cd291b538f5aaebe1606d3849b9b89817666ff2b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/*
 * 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_crtc_internal.h"

/**
 * drm_mode_create_dumb_ioctl - create a dumb backing storage buffer
 * @dev: DRM device
 * @data: ioctl data
 * @file_priv: DRM file info
 *
 * This creates a new dumb buffer in the driver's backing storage manager (GEM,
 * TTM or something else entirely) and returns the resulting buffer handle. This
 * handle can then be wrapped up into a framebuffer modeset object.
 *
 * Note that userspace is not allowed to use such objects for render
 * acceleration - drivers must create their own private ioctls for such a use
 * case.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
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 */
	/* NOTE: DIV_ROUND_UP() can overflow */
	cpp = DIV_ROUND_UP(args->bpp, 8);
	if (!cpp || cpp > 0xffffffffU / args->width)
		return -EINVAL;
	stride = cpp * args->width;
	if (args->height > 0xffffffffU / 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;

	/* call driver ioctl to get mmap offset */
	if (!dev->driver->dumb_map_offset)
		return -ENOSYS;

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

/**
 * drm_mode_destroy_dumb_ioctl - destroy a dumb backing strage buffer
 * @dev: DRM device
 * @data: ioctl data
 * @file_priv: DRM file info
 *
 * This destroys the userspace handle for the given dumb backing storage buffer.
 * Since buffer objects must be reference counted in the kernel a buffer object
 * won't be immediately freed if a framebuffer modeset object still uses it.
 *
 * Called by the user via ioctl.
 *
 * Returns:
 * Zero on success, negative errno on failure.
 */
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_destroy)
		return -ENOSYS;

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