summaryrefslogtreecommitdiffstats
path: root/include/drm/drm_vma_manager.h
blob: 4f8c35206f7cd7802539e1bb6490e5516e6103f4 (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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
#ifndef __DRM_VMA_MANAGER_H__
#define __DRM_VMA_MANAGER_H__

/*
 * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include <drm/drm_mm.h>
#include <linux/mm.h>
#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/types.h>

/* We make up offsets for buffer objects so we can recognize them at
 * mmap time. pgoff in mmap is an unsigned long, so we need to make sure
 * that the faked up offset will fit
 */
#if BITS_PER_LONG == 64
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 256)
#else
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
#endif

struct drm_file;

struct drm_vma_offset_file {
	struct rb_node vm_rb;
	struct drm_file *vm_tag;
	unsigned long vm_count;
};

struct drm_vma_offset_node {
	rwlock_t vm_lock;
	struct drm_mm_node vm_node;
	struct rb_root vm_files;
	void *driver_private;
};

struct drm_vma_offset_manager {
	rwlock_t vm_lock;
	struct drm_mm vm_addr_space_mm;
};

void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
				 unsigned long page_offset, unsigned long size);
void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);

struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
							   unsigned long start,
							   unsigned long pages);
int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
		       struct drm_vma_offset_node *node, unsigned long pages);
void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
			   struct drm_vma_offset_node *node);

int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag);
void drm_vma_node_revoke(struct drm_vma_offset_node *node,
			 struct drm_file *tag);
bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
			     struct drm_file *tag);

/**
 * drm_vma_offset_exact_lookup_locked() - Look up node by exact address
 * @mgr: Manager object
 * @start: Start address (page-based, not byte-based)
 * @pages: Size of object (page-based)
 *
 * Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node.
 * It only returns the exact object with the given start address.
 *
 * RETURNS:
 * Node at exact start address @start.
 */
static inline struct drm_vma_offset_node *
drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr,
				   unsigned long start,
				   unsigned long pages)
{
	struct drm_vma_offset_node *node;

	node = drm_vma_offset_lookup_locked(mgr, start, pages);
	return (node && node->vm_node.start == start) ? node : NULL;
}

/**
 * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
 * @mgr: Manager object
 *
 * Lock VMA manager for extended lookups. Only locked VMA function calls
 * are allowed while holding this lock. All other contexts are blocked from VMA
 * until the lock is released via drm_vma_offset_unlock_lookup().
 *
 * Use this if you need to take a reference to the objects returned by
 * drm_vma_offset_lookup_locked() before releasing this lock again.
 *
 * This lock must not be used for anything else than extended lookups. You must
 * not call any other VMA helpers while holding this lock.
 *
 * Note: You're in atomic-context while holding this lock!
 */
static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
{
	read_lock(&mgr->vm_lock);
}

/**
 * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
 * @mgr: Manager object
 *
 * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
 */
static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
{
	read_unlock(&mgr->vm_lock);
}

/**
 * drm_vma_node_reset() - Initialize or reset node object
 * @node: Node to initialize or reset
 *
 * Reset a node to its initial state. This must be called before using it with
 * any VMA offset manager.
 *
 * This must not be called on an already allocated node, or you will leak
 * memory.
 */
static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
{
	memset(node, 0, sizeof(*node));
	node->vm_files = RB_ROOT;
	rwlock_init(&node->vm_lock);
}

/**
 * drm_vma_node_start() - Return start address for page-based addressing
 * @node: Node to inspect
 *
 * Return the start address of the given node. This can be used as offset into
 * the linear VM space that is provided by the VMA offset manager. Note that
 * this can only be used for page-based addressing. If you need a proper offset
 * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
 * drm_vma_node_offset_addr() helper instead.
 *
 * RETURNS:
 * Start address of @node for page-based addressing. 0 if the node does not
 * have an offset allocated.
 */
static inline unsigned long drm_vma_node_start(const struct drm_vma_offset_node *node)
{
	return node->vm_node.start;
}

/**
 * drm_vma_node_size() - Return size (page-based)
 * @node: Node to inspect
 *
 * Return the size as number of pages for the given node. This is the same size
 * that was passed to drm_vma_offset_add(). If no offset is allocated for the
 * node, this is 0.
 *
 * RETURNS:
 * Size of @node as number of pages. 0 if the node does not have an offset
 * allocated.
 */
static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
{
	return node->vm_node.size;
}

/**
 * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
 * @node: Linked offset node
 *
 * Same as drm_vma_node_start() but returns the address as a valid offset that
 * can be used for user-space mappings during mmap().
 * This must not be called on unlinked nodes.
 *
 * RETURNS:
 * Offset of @node for byte-based addressing. 0 if the node does not have an
 * object allocated.
 */
static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
{
	return ((__u64)node->vm_node.start) << PAGE_SHIFT;
}

/**
 * drm_vma_node_unmap() - Unmap offset node
 * @node: Offset node
 * @file_mapping: Address space to unmap @node from
 *
 * Unmap all userspace mappings for a given offset node. The mappings must be
 * associated with the @file_mapping address-space. If no offset exists
 * nothing is done.
 *
 * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
 * is not called on this node concurrently.
 */
static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
				      struct address_space *file_mapping)
{
	if (drm_mm_node_allocated(&node->vm_node))
		unmap_mapping_range(file_mapping,
				    drm_vma_node_offset_addr(node),
				    drm_vma_node_size(node) << PAGE_SHIFT, 1);
}

/**
 * drm_vma_node_verify_access() - Access verification helper for TTM
 * @node: Offset node
 * @tag: Tag of file to check
 *
 * This checks whether @tag is granted access to @node. It is the same as
 * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
 * verify_access() callbacks.
 *
 * RETURNS:
 * 0 if access is granted, -EACCES otherwise.
 */
static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
					     struct drm_file *tag)
{
	return drm_vma_node_is_allowed(node, tag) ? 0 : -EACCES;
}

#endif /* __DRM_VMA_MANAGER_H__ */