1 /**************************************************************************
2 *
3 * Copyright (c) 2006-2022 VMware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27 /*
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29 */
30 /** @file ttm_object.h
31 *
32 * Base- and reference object implementation for the various
33 * ttm objects. Implements reference counting, minimal security checks
34 * and release on file close.
35 */
36
37 #ifndef _TTM_OBJECT_H_
38 #define _TTM_OBJECT_H_
39
40 #include <linux/dma-buf.h>
41 #include <linux/kref.h>
42 #include <linux/list.h>
43 #include <linux/rcupdate.h>
44
45 /**
46 * enum ttm_object_type
47 *
48 * One entry per ttm object type.
49 * Device-specific types should use the
50 * ttm_driver_typex types.
51 */
52
53 enum ttm_object_type {
54 ttm_fence_type,
55 ttm_lock_type,
56 ttm_prime_type,
57 ttm_driver_type0 = 256,
58 ttm_driver_type1,
59 ttm_driver_type2,
60 ttm_driver_type3,
61 ttm_driver_type4,
62 ttm_driver_type5
63 };
64
65 struct ttm_object_file;
66 struct ttm_object_device;
67
68 /**
69 * struct ttm_base_object
70 *
71 * @hash: hash entry for the per-device object hash.
72 * @type: derived type this object is base class for.
73 * @shareable: Other ttm_object_files can access this object.
74 *
75 * @tfile: Pointer to ttm_object_file of the creator.
76 * NULL if the object was not created by a user request.
77 * (kernel object).
78 *
79 * @refcount: Number of references to this object, not
80 * including the hash entry. A reference to a base object can
81 * only be held by a ref object.
82 *
83 * @refcount_release: A function to be called when there are
84 * no more references to this object. This function should
85 * destroy the object (or make sure destruction eventually happens),
86 * and when it is called, the object has
87 * already been taken out of the per-device hash. The parameter
88 * "base" should be set to NULL by the function.
89 *
90 * @ref_obj_release: A function to be called when a reference object
91 * with another ttm_ref_type than TTM_REF_USAGE is deleted.
92 * This function may, for example, release a lock held by a user-space
93 * process.
94 *
95 * This struct is intended to be used as a base struct for objects that
96 * are visible to user-space. It provides a global name, race-safe
97 * access and refcounting, minimal access control and hooks for unref actions.
98 */
99
100 struct ttm_base_object {
101 struct rcu_head rhead;
102 struct ttm_object_file *tfile;
103 struct kref refcount;
104 void (*refcount_release) (struct ttm_base_object **base);
105 u64 handle;
106 enum ttm_object_type object_type;
107 u32 shareable;
108 };
109
110
111 /**
112 * struct ttm_prime_object - Modified base object that is prime-aware
113 *
114 * @base: struct ttm_base_object that we derive from
115 * @mutex: Mutex protecting the @dma_buf member.
116 * @size: Size of the dma_buf associated with this object
117 * @real_type: Type of the underlying object. Needed since we're setting
118 * the value of @base::object_type to ttm_prime_type
119 * @dma_buf: Non ref-coutned pointer to a struct dma_buf created from this
120 * object.
121 * @refcount_release: The underlying object's release method. Needed since
122 * we set @base::refcount_release to our own release method.
123 */
124
125 struct ttm_prime_object {
126 struct ttm_base_object base;
127 struct mutex mutex;
128 size_t size;
129 enum ttm_object_type real_type;
130 struct dma_buf *dma_buf;
131 void (*refcount_release) (struct ttm_base_object **);
132 };
133
134 /**
135 * ttm_base_object_init
136 *
137 * @tfile: Pointer to a struct ttm_object_file.
138 * @base: The struct ttm_base_object to initialize.
139 * @shareable: This object is shareable with other applications.
140 * (different @tfile pointers.)
141 * @type: The object type.
142 * @refcount_release: See the struct ttm_base_object description.
143 * @ref_obj_release: See the struct ttm_base_object description.
144 *
145 * Initializes a struct ttm_base_object.
146 */
147
148 extern int ttm_base_object_init(struct ttm_object_file *tfile,
149 struct ttm_base_object *base,
150 bool shareable,
151 enum ttm_object_type type,
152 void (*refcount_release) (struct ttm_base_object
153 **));
154
155 /**
156 * ttm_base_object_lookup
157 *
158 * @tfile: Pointer to a struct ttm_object_file.
159 * @key: Hash key
160 *
161 * Looks up a struct ttm_base_object with the key @key.
162 */
163
164 extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
165 *tfile, uint64_t key);
166
167 /**
168 * ttm_base_object_lookup_for_ref
169 *
170 * @tdev: Pointer to a struct ttm_object_device.
171 * @key: Hash key
172 *
173 * Looks up a struct ttm_base_object with the key @key.
174 * This function should only be used when the struct tfile associated with the
175 * caller doesn't yet have a reference to the base object.
176 */
177
178 extern struct ttm_base_object *
179 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint64_t key);
180
181 /**
182 * ttm_base_object_unref
183 *
184 * @p_base: Pointer to a pointer referencing a struct ttm_base_object.
185 *
186 * Decrements the base object refcount and clears the pointer pointed to by
187 * p_base.
188 */
189
190 extern void ttm_base_object_unref(struct ttm_base_object **p_base);
191
192 /**
193 * ttm_ref_object_add.
194 *
195 * @tfile: A struct ttm_object_file representing the application owning the
196 * ref_object.
197 * @base: The base object to reference.
198 * @ref_type: The type of reference.
199 * @existed: Upon completion, indicates that an identical reference object
200 * already existed, and the refcount was upped on that object instead.
201 * @require_existed: Fail with -EPERM if an identical ref object didn't
202 * already exist.
203 *
204 * Checks that the base object is shareable and adds a ref object to it.
205 *
206 * Adding a ref object to a base object is basically like referencing the
207 * base object, but a user-space application holds the reference. When the
208 * file corresponding to @tfile is closed, all its reference objects are
209 * deleted. A reference object can have different types depending on what
210 * it's intended for. It can be refcounting to prevent object destruction,
211 * When user-space takes a lock, it can add a ref object to that lock to
212 * make sure the lock is released if the application dies. A ref object
213 * will hold a single reference on a base object.
214 */
215 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
216 struct ttm_base_object *base,
217 bool *existed,
218 bool require_existed);
219
220 /**
221 * ttm_ref_object_base_unref
222 *
223 * @key: Key representing the base object.
224 * @ref_type: Ref type of the ref object to be dereferenced.
225 *
226 * Unreference a ref object with type @ref_type
227 * on the base object identified by @key. If there are no duplicate
228 * references, the ref object will be destroyed and the base object
229 * will be unreferenced.
230 */
231 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
232 unsigned long key);
233
234 /**
235 * ttm_object_file_init - initialize a struct ttm_object file
236 *
237 * @tdev: A struct ttm_object device this file is initialized on.
238 *
239 * This is typically called by the file_ops::open function.
240 */
241
242 extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
243 *tdev);
244
245 /**
246 * ttm_object_file_release - release data held by a ttm_object_file
247 *
248 * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
249 * *p_tfile will be set to NULL by this function.
250 *
251 * Releases all data associated by a ttm_object_file.
252 * Typically called from file_ops::release. The caller must
253 * ensure that there are no concurrent users of tfile.
254 */
255
256 extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
257
258 /**
259 * ttm_object device init - initialize a struct ttm_object_device
260 *
261 * @ops: DMA buf ops for prime objects of this device.
262 *
263 * This function is typically called on device initialization to prepare
264 * data structures needed for ttm base and ref objects.
265 */
266
267 extern struct ttm_object_device *
268 ttm_object_device_init(const struct dma_buf_ops *ops);
269
270 /**
271 * ttm_object_device_release - release data held by a ttm_object_device
272 *
273 * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
274 * *p_tdev will be set to NULL by this function.
275 *
276 * Releases all data associated by a ttm_object_device.
277 * Typically called from driver::unload before the destruction of the
278 * device private data structure.
279 */
280
281 extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
282
283 #define ttm_base_object_kfree(__object, __base)\
284 kfree_rcu(__object, __base.rhead)
285
286 extern int ttm_prime_object_init(struct ttm_object_file *tfile,
287 size_t size,
288 struct ttm_prime_object *prime,
289 bool shareable,
290 enum ttm_object_type type,
291 void (*refcount_release)
292 (struct ttm_base_object **));
293
294 static inline enum ttm_object_type
ttm_base_object_type(struct ttm_base_object * base)295 ttm_base_object_type(struct ttm_base_object *base)
296 {
297 return (base->object_type == ttm_prime_type) ?
298 container_of(base, struct ttm_prime_object, base)->real_type :
299 base->object_type;
300 }
301 extern int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
302 int fd, u32 *handle);
303 extern int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
304 uint32_t handle, uint32_t flags,
305 int *prime_fd);
306
307 #define ttm_prime_object_kfree(__obj, __prime) \
308 kfree_rcu(__obj, __prime.base.rhead)
309
310 #endif
311