1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 2 /****************************************************************************** 3 * 4 * Module Name: exmutex - ASL Mutex Acquire/Release functions 5 * 6 * Copyright (C) 2000 - 2021, Intel Corp. 7 * 8 *****************************************************************************/ 9 10 #include <acpi/acpi.h> 11 #include "accommon.h" 12 #include "acinterp.h" 13 #include "acevents.h" 14 15 #define _COMPONENT ACPI_EXECUTER 16 ACPI_MODULE_NAME("exmutex") 17 18 /* Local prototypes */ 19 static void 20 acpi_ex_link_mutex(union acpi_operand_object *obj_desc, 21 struct acpi_thread_state *thread); 22 23 /******************************************************************************* 24 * 25 * FUNCTION: acpi_ex_unlink_mutex 26 * 27 * PARAMETERS: obj_desc - The mutex to be unlinked 28 * 29 * RETURN: None 30 * 31 * DESCRIPTION: Remove a mutex from the "AcquiredMutex" list 32 * 33 ******************************************************************************/ 34 35 void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc) 36 { 37 struct acpi_thread_state *thread = obj_desc->mutex.owner_thread; 38 39 if (!thread) { 40 return; 41 } 42 43 /* Doubly linked list */ 44 45 if (obj_desc->mutex.next) { 46 (obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev; 47 } 48 49 if (obj_desc->mutex.prev) { 50 (obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next; 51 52 /* 53 * Migrate the previous sync level associated with this mutex to 54 * the previous mutex on the list so that it may be preserved. 55 * This handles the case where several mutexes have been acquired 56 * at the same level, but are not released in opposite order. 57 */ 58 (obj_desc->mutex.prev)->mutex.original_sync_level = 59 obj_desc->mutex.original_sync_level; 60 } else { 61 thread->acquired_mutex_list = obj_desc->mutex.next; 62 } 63 } 64 65 /******************************************************************************* 66 * 67 * FUNCTION: acpi_ex_link_mutex 68 * 69 * PARAMETERS: obj_desc - The mutex to be linked 70 * thread - Current executing thread object 71 * 72 * RETURN: None 73 * 74 * DESCRIPTION: Add a mutex to the "AcquiredMutex" list for this walk 75 * 76 ******************************************************************************/ 77 78 static void 79 acpi_ex_link_mutex(union acpi_operand_object *obj_desc, 80 struct acpi_thread_state *thread) 81 { 82 union acpi_operand_object *list_head; 83 84 list_head = thread->acquired_mutex_list; 85 86 /* This object will be the first object in the list */ 87 88 obj_desc->mutex.prev = NULL; 89 obj_desc->mutex.next = list_head; 90 91 /* Update old first object to point back to this object */ 92 93 if (list_head) { 94 list_head->mutex.prev = obj_desc; 95 } 96 97 /* Update list head */ 98 99 thread->acquired_mutex_list = obj_desc; 100 } 101 102 /******************************************************************************* 103 * 104 * FUNCTION: acpi_ex_acquire_mutex_object 105 * 106 * PARAMETERS: timeout - Timeout in milliseconds 107 * obj_desc - Mutex object 108 * thread_id - Current thread state 109 * 110 * RETURN: Status 111 * 112 * DESCRIPTION: Acquire an AML mutex, low-level interface. Provides a common 113 * path that supports multiple acquires by the same thread. 114 * 115 * MUTEX: Interpreter must be locked 116 * 117 * NOTE: This interface is called from three places: 118 * 1) From acpi_ex_acquire_mutex, via an AML Acquire() operator 119 * 2) From acpi_ex_acquire_global_lock when an AML Field access requires the 120 * global lock 121 * 3) From the external interface, acpi_acquire_global_lock 122 * 123 ******************************************************************************/ 124 125 acpi_status 126 acpi_ex_acquire_mutex_object(u16 timeout, 127 union acpi_operand_object *obj_desc, 128 acpi_thread_id thread_id) 129 { 130 acpi_status status; 131 132 ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex_object, obj_desc); 133 134 if (!obj_desc) { 135 return_ACPI_STATUS(AE_BAD_PARAMETER); 136 } 137 138 /* Support for multiple acquires by the owning thread */ 139 140 if (obj_desc->mutex.thread_id == thread_id) { 141 /* 142 * The mutex is already owned by this thread, just increment the 143 * acquisition depth 144 */ 145 obj_desc->mutex.acquisition_depth++; 146 return_ACPI_STATUS(AE_OK); 147 } 148 149 /* Acquire the mutex, wait if necessary. Special case for Global Lock */ 150 151 if (obj_desc == acpi_gbl_global_lock_mutex) { 152 status = acpi_ev_acquire_global_lock(timeout); 153 } else { 154 status = 155 acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex, 156 timeout); 157 } 158 159 if (ACPI_FAILURE(status)) { 160 161 /* Includes failure from a timeout on time_desc */ 162 163 return_ACPI_STATUS(status); 164 } 165 166 /* Acquired the mutex: update mutex object */ 167 168 obj_desc->mutex.thread_id = thread_id; 169 obj_desc->mutex.acquisition_depth = 1; 170 obj_desc->mutex.original_sync_level = 0; 171 obj_desc->mutex.owner_thread = NULL; /* Used only for AML Acquire() */ 172 173 return_ACPI_STATUS(AE_OK); 174 } 175 176 /******************************************************************************* 177 * 178 * FUNCTION: acpi_ex_acquire_mutex 179 * 180 * PARAMETERS: time_desc - Timeout integer 181 * obj_desc - Mutex object 182 * walk_state - Current method execution state 183 * 184 * RETURN: Status 185 * 186 * DESCRIPTION: Acquire an AML mutex 187 * 188 ******************************************************************************/ 189 190 acpi_status 191 acpi_ex_acquire_mutex(union acpi_operand_object *time_desc, 192 union acpi_operand_object *obj_desc, 193 struct acpi_walk_state *walk_state) 194 { 195 acpi_status status; 196 197 ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc); 198 199 if (!obj_desc) { 200 return_ACPI_STATUS(AE_BAD_PARAMETER); 201 } 202 203 /* Must have a valid thread state struct */ 204 205 if (!walk_state->thread) { 206 ACPI_ERROR((AE_INFO, 207 "Cannot acquire Mutex [%4.4s], null thread info", 208 acpi_ut_get_node_name(obj_desc->mutex.node))); 209 return_ACPI_STATUS(AE_AML_INTERNAL); 210 } 211 212 /* 213 * Current sync level must be less than or equal to the sync level 214 * of the mutex. This mechanism provides some deadlock prevention. 215 */ 216 if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) { 217 ACPI_ERROR((AE_INFO, 218 "Cannot acquire Mutex [%4.4s], " 219 "current SyncLevel is too large (%u)", 220 acpi_ut_get_node_name(obj_desc->mutex.node), 221 walk_state->thread->current_sync_level)); 222 return_ACPI_STATUS(AE_AML_MUTEX_ORDER); 223 } 224 225 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, 226 "Acquiring: Mutex SyncLevel %u, Thread SyncLevel %u, " 227 "Depth %u TID %p\n", 228 obj_desc->mutex.sync_level, 229 walk_state->thread->current_sync_level, 230 obj_desc->mutex.acquisition_depth, 231 walk_state->thread)); 232 233 status = acpi_ex_acquire_mutex_object((u16)time_desc->integer.value, 234 obj_desc, 235 walk_state->thread->thread_id); 236 237 if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) { 238 239 /* Save Thread object, original/current sync levels */ 240 241 obj_desc->mutex.owner_thread = walk_state->thread; 242 obj_desc->mutex.original_sync_level = 243 walk_state->thread->current_sync_level; 244 walk_state->thread->current_sync_level = 245 obj_desc->mutex.sync_level; 246 247 /* Link the mutex to the current thread for force-unlock at method exit */ 248 249 acpi_ex_link_mutex(obj_desc, walk_state->thread); 250 } 251 252 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, 253 "Acquired: Mutex SyncLevel %u, Thread SyncLevel %u, Depth %u\n", 254 obj_desc->mutex.sync_level, 255 walk_state->thread->current_sync_level, 256 obj_desc->mutex.acquisition_depth)); 257 258 return_ACPI_STATUS(status); 259 } 260 261 /******************************************************************************* 262 * 263 * FUNCTION: acpi_ex_release_mutex_object 264 * 265 * PARAMETERS: obj_desc - The object descriptor for this op 266 * 267 * RETURN: Status 268 * 269 * DESCRIPTION: Release a previously acquired Mutex, low level interface. 270 * Provides a common path that supports multiple releases (after 271 * previous multiple acquires) by the same thread. 272 * 273 * MUTEX: Interpreter must be locked 274 * 275 * NOTE: This interface is called from three places: 276 * 1) From acpi_ex_release_mutex, via an AML Acquire() operator 277 * 2) From acpi_ex_release_global_lock when an AML Field access requires the 278 * global lock 279 * 3) From the external interface, acpi_release_global_lock 280 * 281 ******************************************************************************/ 282 283 acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc) 284 { 285 acpi_status status = AE_OK; 286 287 ACPI_FUNCTION_TRACE(ex_release_mutex_object); 288 289 if (obj_desc->mutex.acquisition_depth == 0) { 290 return_ACPI_STATUS(AE_NOT_ACQUIRED); 291 } 292 293 /* Match multiple Acquires with multiple Releases */ 294 295 obj_desc->mutex.acquisition_depth--; 296 if (obj_desc->mutex.acquisition_depth != 0) { 297 298 /* Just decrement the depth and return */ 299 300 return_ACPI_STATUS(AE_OK); 301 } 302 303 if (obj_desc->mutex.owner_thread) { 304 305 /* Unlink the mutex from the owner's list */ 306 307 acpi_ex_unlink_mutex(obj_desc); 308 obj_desc->mutex.owner_thread = NULL; 309 } 310 311 /* Release the mutex, special case for Global Lock */ 312 313 if (obj_desc == acpi_gbl_global_lock_mutex) { 314 status = acpi_ev_release_global_lock(); 315 } else { 316 acpi_os_release_mutex(obj_desc->mutex.os_mutex); 317 } 318 319 /* Clear mutex info */ 320 321 obj_desc->mutex.thread_id = 0; 322 return_ACPI_STATUS(status); 323 } 324 325 /******************************************************************************* 326 * 327 * FUNCTION: acpi_ex_release_mutex 328 * 329 * PARAMETERS: obj_desc - The object descriptor for this op 330 * walk_state - Current method execution state 331 * 332 * RETURN: Status 333 * 334 * DESCRIPTION: Release a previously acquired Mutex. 335 * 336 ******************************************************************************/ 337 338 acpi_status 339 acpi_ex_release_mutex(union acpi_operand_object *obj_desc, 340 struct acpi_walk_state *walk_state) 341 { 342 u8 previous_sync_level; 343 struct acpi_thread_state *owner_thread; 344 acpi_status status = AE_OK; 345 346 ACPI_FUNCTION_TRACE(ex_release_mutex); 347 348 if (!obj_desc) { 349 return_ACPI_STATUS(AE_BAD_PARAMETER); 350 } 351 352 owner_thread = obj_desc->mutex.owner_thread; 353 354 /* The mutex must have been previously acquired in order to release it */ 355 356 if (!owner_thread) { 357 ACPI_ERROR((AE_INFO, 358 "Cannot release Mutex [%4.4s], not acquired", 359 acpi_ut_get_node_name(obj_desc->mutex.node))); 360 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED); 361 } 362 363 /* Must have a valid thread ID */ 364 365 if (!walk_state->thread) { 366 ACPI_ERROR((AE_INFO, 367 "Cannot release Mutex [%4.4s], null thread info", 368 acpi_ut_get_node_name(obj_desc->mutex.node))); 369 return_ACPI_STATUS(AE_AML_INTERNAL); 370 } 371 372 /* 373 * The Mutex is owned, but this thread must be the owner. 374 * Special case for Global Lock, any thread can release 375 */ 376 if ((owner_thread->thread_id != walk_state->thread->thread_id) && 377 (obj_desc != acpi_gbl_global_lock_mutex)) { 378 ACPI_ERROR((AE_INFO, 379 "Thread %u cannot release Mutex [%4.4s] acquired by thread %u", 380 (u32)walk_state->thread->thread_id, 381 acpi_ut_get_node_name(obj_desc->mutex.node), 382 (u32)owner_thread->thread_id)); 383 return_ACPI_STATUS(AE_AML_NOT_OWNER); 384 } 385 386 /* 387 * The sync level of the mutex must be equal to the current sync level. In 388 * other words, the current level means that at least one mutex at that 389 * level is currently being held. Attempting to release a mutex of a 390 * different level can only mean that the mutex ordering rule is being 391 * violated. This behavior is clarified in ACPI 4.0 specification. 392 */ 393 if (obj_desc->mutex.sync_level != owner_thread->current_sync_level) { 394 ACPI_ERROR((AE_INFO, 395 "Cannot release Mutex [%4.4s], SyncLevel mismatch: " 396 "mutex %u current %u", 397 acpi_ut_get_node_name(obj_desc->mutex.node), 398 obj_desc->mutex.sync_level, 399 walk_state->thread->current_sync_level)); 400 return_ACPI_STATUS(AE_AML_MUTEX_ORDER); 401 } 402 403 /* 404 * Get the previous sync_level from the head of the acquired mutex list. 405 * This handles the case where several mutexes at the same level have been 406 * acquired, but are not released in reverse order. 407 */ 408 previous_sync_level = 409 owner_thread->acquired_mutex_list->mutex.original_sync_level; 410 411 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, 412 "Releasing: Object SyncLevel %u, Thread SyncLevel %u, " 413 "Prev SyncLevel %u, Depth %u TID %p\n", 414 obj_desc->mutex.sync_level, 415 walk_state->thread->current_sync_level, 416 previous_sync_level, 417 obj_desc->mutex.acquisition_depth, 418 walk_state->thread)); 419 420 status = acpi_ex_release_mutex_object(obj_desc); 421 if (ACPI_FAILURE(status)) { 422 return_ACPI_STATUS(status); 423 } 424 425 if (obj_desc->mutex.acquisition_depth == 0) { 426 427 /* Restore the previous sync_level */ 428 429 owner_thread->current_sync_level = previous_sync_level; 430 } 431 432 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, 433 "Released: Object SyncLevel %u, Thread SyncLevel, %u, " 434 "Prev SyncLevel %u, Depth %u\n", 435 obj_desc->mutex.sync_level, 436 walk_state->thread->current_sync_level, 437 previous_sync_level, 438 obj_desc->mutex.acquisition_depth)); 439 440 return_ACPI_STATUS(status); 441 } 442 443 /******************************************************************************* 444 * 445 * FUNCTION: acpi_ex_release_all_mutexes 446 * 447 * PARAMETERS: thread - Current executing thread object 448 * 449 * RETURN: Status 450 * 451 * DESCRIPTION: Release all mutexes held by this thread 452 * 453 * NOTE: This function is called as the thread is exiting the interpreter. 454 * Mutexes are not released when an individual control method is exited, but 455 * only when the parent thread actually exits the interpreter. This allows one 456 * method to acquire a mutex, and a different method to release it, as long as 457 * this is performed underneath a single parent control method. 458 * 459 ******************************************************************************/ 460 461 void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread) 462 { 463 union acpi_operand_object *next = thread->acquired_mutex_list; 464 union acpi_operand_object *obj_desc; 465 466 ACPI_FUNCTION_TRACE(ex_release_all_mutexes); 467 468 /* Traverse the list of owned mutexes, releasing each one */ 469 470 while (next) { 471 obj_desc = next; 472 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, 473 "Mutex [%4.4s] force-release, SyncLevel %u Depth %u\n", 474 obj_desc->mutex.node->name.ascii, 475 obj_desc->mutex.sync_level, 476 obj_desc->mutex.acquisition_depth)); 477 478 /* Release the mutex, special case for Global Lock */ 479 480 if (obj_desc == acpi_gbl_global_lock_mutex) { 481 482 /* Ignore errors */ 483 484 (void)acpi_ev_release_global_lock(); 485 } else { 486 acpi_os_release_mutex(obj_desc->mutex.os_mutex); 487 } 488 489 /* Update Thread sync_level (Last mutex is the important one) */ 490 491 thread->current_sync_level = 492 obj_desc->mutex.original_sync_level; 493 494 /* Mark mutex unowned */ 495 496 next = obj_desc->mutex.next; 497 498 obj_desc->mutex.prev = NULL; 499 obj_desc->mutex.next = NULL; 500 obj_desc->mutex.acquisition_depth = 0; 501 obj_desc->mutex.owner_thread = NULL; 502 obj_desc->mutex.thread_id = 0; 503 } 504 505 return_VOID; 506 } 507