1/* $NetBSD: drm_gem_vm.c,v 1.6 2015/03/09 01:29:40 riastradh Exp $ */
2
3/*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: drm_gem_vm.c,v 1.6 2015/03/09 01:29:40 riastradh Exp $");
34
35#include <sys/types.h>
36
37#include <uvm/uvm_extern.h>
38
39#include <drm/drmP.h>
40#include <drm/drm_vma_manager.h>
41
42static int drm_gem_mmap_object_locked(struct drm_device *, off_t, size_t,
43 int, struct uvm_object **, voff_t *, struct file *);
44
45void
46drm_gem_pager_reference(struct uvm_object *uobj)
47{
48 struct drm_gem_object *const obj = container_of(uobj,
49 struct drm_gem_object, gemo_uvmobj);
50
51 drm_gem_object_reference(obj);
52}
53
54void
55drm_gem_pager_detach(struct uvm_object *uobj)
56{
57 struct drm_gem_object *const obj = container_of(uobj,
58 struct drm_gem_object, gemo_uvmobj);
59
60 drm_gem_object_unreference_unlocked(obj);
61}
62
63int
64drm_gem_or_legacy_mmap_object(struct drm_device *dev, off_t byte_offset,
65 size_t nbytes, int prot, struct uvm_object **uobjp, voff_t *uoffsetp,
66 struct file *file)
67{
68 int ret;
69
70 ret = drm_gem_mmap_object(dev, byte_offset, nbytes, prot, uobjp,
71 uoffsetp, file);
72 if (ret)
73 return ret;
74 if (*uobjp != NULL)
75 return 0;
76
77 return drm_mmap_object(dev, byte_offset, nbytes, prot, uobjp,
78 uoffsetp, file);
79}
80
81int
82drm_gem_mmap_object(struct drm_device *dev, off_t byte_offset, size_t nbytes,
83 int prot, struct uvm_object **uobjp, voff_t *uoffsetp, struct file *file)
84{
85 int ret;
86
87 mutex_lock(&dev->struct_mutex);
88 ret = drm_gem_mmap_object_locked(dev, byte_offset, nbytes, prot,
89 uobjp, uoffsetp, file);
90 mutex_unlock(&dev->struct_mutex);
91
92 return ret;
93}
94
95static int
96drm_gem_mmap_object_locked(struct drm_device *dev, off_t byte_offset,
97 size_t nbytes, int prot __unused, struct uvm_object **uobjp,
98 voff_t *uoffsetp, struct file *file)
99{
100 const unsigned long startpage = (byte_offset >> PAGE_SHIFT);
101 const unsigned long npages = (nbytes >> PAGE_SHIFT);
102
103 KASSERT(mutex_is_locked(&dev->struct_mutex));
104 KASSERT(drm_core_check_feature(dev, DRIVER_GEM));
105 KASSERT(dev->driver->gem_uvm_ops != NULL);
106 KASSERT(prot == (prot & (PROT_READ | PROT_WRITE)));
107 KASSERT(0 <= byte_offset);
108 KASSERT(byte_offset == (byte_offset & ~(PAGE_SIZE-1)));
109 KASSERT(nbytes == (npages << PAGE_SHIFT));
110
111 struct drm_vma_offset_node *const node =
112 drm_vma_offset_exact_lookup(dev->vma_offset_manager, startpage,
113 npages);
114 if (node == NULL) {
115 /* Fall back to vanilla device mappings. */
116 *uobjp = NULL;
117 *uoffsetp = (voff_t)-1;
118 return 0;
119 }
120
121 if (!drm_vma_node_is_allowed(node, file))
122 return -EACCES;
123
124 struct drm_gem_object *const obj = container_of(node,
125 struct drm_gem_object, vma_node);
126 KASSERT(obj->dev == dev);
127
128 /* Success! */
129 drm_gem_object_reference(obj);
130 *uobjp = &obj->gemo_uvmobj;
131 *uoffsetp = 0;
132 return 0;
133}
134