1 /* $NetBSD: drm_gem_vm.c,v 1.15 2022/07/06 01:12:45 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 1.15 2022/07/06 01:12:45 riastradh Exp $");
34
35 #include <sys/types.h>
36 #include <sys/file.h>
37 #include <sys/mman.h>
38
39 #include <uvm/uvm_extern.h>
40
41 #include <drm/drm_drv.h>
42 #include <drm/drm_gem.h>
43 #include <drm/drm_legacy.h>
44 #include <drm/drm_vma_manager.h>
45
46 static int drm_gem_mmap_object_locked(struct drm_device *, off_t, size_t,
47 int, struct uvm_object **, voff_t *, struct file *);
48
49 void
drm_gem_pager_reference(struct uvm_object * uobj)50 drm_gem_pager_reference(struct uvm_object *uobj)
51 {
52 struct drm_gem_object *const obj = container_of(uobj,
53 struct drm_gem_object, gemo_uvmobj);
54
55 drm_gem_object_get(obj);
56 }
57
58 void
drm_gem_pager_detach(struct uvm_object * uobj)59 drm_gem_pager_detach(struct uvm_object *uobj)
60 {
61 struct drm_gem_object *const obj = container_of(uobj,
62 struct drm_gem_object, gemo_uvmobj);
63
64 drm_gem_object_put_unlocked(obj);
65 }
66
67 int
drm_gem_or_legacy_mmap_object(struct drm_device * dev,off_t byte_offset,size_t nbytes,int prot,struct uvm_object ** uobjp,voff_t * uoffsetp,struct file * file)68 drm_gem_or_legacy_mmap_object(struct drm_device *dev, off_t byte_offset,
69 size_t nbytes, int prot, struct uvm_object **uobjp, voff_t *uoffsetp,
70 struct file *file)
71 {
72 int ret;
73
74 KASSERT(nbytes > 0);
75
76 ret = drm_gem_mmap_object(dev, byte_offset, nbytes, prot, uobjp,
77 uoffsetp, file);
78 if (ret)
79 return ret;
80 if (*uobjp != NULL)
81 return 0;
82
83 return drm_legacy_mmap_object(dev, byte_offset, nbytes, prot, uobjp,
84 uoffsetp, file);
85 }
86
87 int
drm_gem_mmap_object(struct drm_device * dev,off_t byte_offset,size_t nbytes,int prot,struct uvm_object ** uobjp,voff_t * uoffsetp,struct file * file)88 drm_gem_mmap_object(struct drm_device *dev, off_t byte_offset, size_t nbytes,
89 int prot, struct uvm_object **uobjp, voff_t *uoffsetp, struct file *file)
90 {
91 int ret;
92
93 KASSERT(nbytes > 0);
94
95 mutex_lock(&dev->struct_mutex);
96 ret = drm_gem_mmap_object_locked(dev, byte_offset, nbytes, prot,
97 uobjp, uoffsetp, file);
98 mutex_unlock(&dev->struct_mutex);
99
100 return ret;
101 }
102
103 static int
drm_gem_mmap_object_locked(struct drm_device * dev,off_t byte_offset,size_t nbytes,int prot __unused,struct uvm_object ** uobjp,voff_t * uoffsetp,struct file * fp)104 drm_gem_mmap_object_locked(struct drm_device *dev, off_t byte_offset,
105 size_t nbytes, int prot __unused, struct uvm_object **uobjp,
106 voff_t *uoffsetp, struct file *fp)
107 {
108 struct drm_file *file = fp->f_data;
109 const unsigned long startpage = (byte_offset >> PAGE_SHIFT);
110 const unsigned long npages = (nbytes >> PAGE_SHIFT);
111
112 KASSERT(mutex_is_locked(&dev->struct_mutex));
113 KASSERT(drm_core_check_feature(dev, DRIVER_GEM));
114 KASSERT(dev->driver->gem_uvm_ops != NULL);
115 KASSERT(prot == (prot & (PROT_READ | PROT_WRITE)));
116 KASSERT(0 <= byte_offset);
117 KASSERT(byte_offset == (byte_offset & ~(PAGE_SIZE-1)));
118 KASSERT(nbytes == (npages << PAGE_SHIFT));
119
120 struct drm_vma_offset_node *const node =
121 drm_vma_offset_exact_lookup(dev->vma_offset_manager, startpage,
122 npages);
123 if (node == NULL) {
124 /* Fall back to vanilla device mappings. */
125 *uobjp = NULL;
126 *uoffsetp = (voff_t)-1;
127 return 0;
128 }
129
130 if (!drm_vma_node_is_allowed(node, file))
131 return -EACCES;
132
133 struct drm_gem_object *const obj = container_of(node,
134 struct drm_gem_object, vma_node);
135 KASSERT(obj->dev == dev);
136
137 /* Success! */
138 drm_gem_object_get(obj);
139 *uobjp = &obj->gemo_uvmobj;
140 *uoffsetp = 0;
141 return 0;
142 }
143