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 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 struct ttm_base_object * 311 ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint64_t key); 312 313 /** 314 * ttm_base_object_noref_release - release a base object pointer looked up 315 * without reference 316 * 317 * Releases a base object pointer looked up with ttm_base_object_noref_lookup(). 318 */ 319 static inline void ttm_base_object_noref_release(void) 320 { 321 __acquire(RCU); 322 rcu_read_unlock(); 323 } 324 #endif 325