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 - 2025, 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
16ACPI_MODULE_NAME("exmutex")
17
18/* Local prototypes */
19static void
20acpi_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
35void 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
78static void
79acpi_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
125acpi_status
126acpi_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(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
190acpi_status
191acpi_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(timeout: (u16)time_desc->integer.value,
234 obj_desc,
235 thread_id: 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, thread: 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
283acpi_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
338acpi_status
339acpi_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
461void 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