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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 - 2020, 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 : 56 : void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
36 : : {
37 : 56 : struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;
38 : :
39 [ + - ]: 56 : if (!thread) {
40 : : return;
41 : : }
42 : :
43 : : /* Doubly linked list */
44 : :
45 [ - + ]: 56 : if (obj_desc->mutex.next) {
46 : 0 : (obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
47 : : }
48 : :
49 [ - + ]: 56 : if (obj_desc->mutex.prev) {
50 : 0 : (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 : 0 : (obj_desc->mutex.prev)->mutex.original_sync_level =
59 : 0 : obj_desc->mutex.original_sync_level;
60 : : } else {
61 : 56 : 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 : 280 : acpi_ex_acquire_mutex_object(u16 timeout,
127 : : union acpi_operand_object *obj_desc,
128 : : acpi_thread_id thread_id)
129 : : {
130 : 280 : acpi_status status;
131 : :
132 : 280 : ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex_object, obj_desc);
133 : :
134 [ + - ]: 280 : if (!obj_desc) {
135 : : return_ACPI_STATUS(AE_BAD_PARAMETER);
136 : : }
137 : :
138 : : /* Support for multiple acquires by the owning thread */
139 : :
140 [ - + ]: 280 : 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 : 0 : obj_desc->mutex.acquisition_depth++;
146 : 0 : return_ACPI_STATUS(AE_OK);
147 : : }
148 : :
149 : : /* Acquire the mutex, wait if necessary. Special case for Global Lock */
150 : :
151 [ + + ]: 280 : if (obj_desc == acpi_gbl_global_lock_mutex) {
152 : 224 : status = acpi_ev_acquire_global_lock(timeout);
153 : : } else {
154 : 56 : status =
155 : 56 : acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex,
156 : : timeout);
157 : : }
158 : :
159 [ + - ]: 280 : 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 : 280 : obj_desc->mutex.thread_id = thread_id;
169 : 280 : obj_desc->mutex.acquisition_depth = 1;
170 : 280 : obj_desc->mutex.original_sync_level = 0;
171 : 280 : obj_desc->mutex.owner_thread = NULL; /* Used only for AML Acquire() */
172 : :
173 : 280 : 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 : 56 : 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 : 56 : acpi_status status;
196 : :
197 : 56 : ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc);
198 : :
199 [ + - ]: 56 : if (!obj_desc) {
200 : : return_ACPI_STATUS(AE_BAD_PARAMETER);
201 : : }
202 : :
203 : : /* Must have a valid thread state struct */
204 : :
205 [ - + ]: 56 : if (!walk_state->thread) {
206 : 0 : ACPI_ERROR((AE_INFO,
207 : : "Cannot acquire Mutex [%4.4s], null thread info",
208 : : acpi_ut_get_node_name(obj_desc->mutex.node)));
209 : 0 : 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 [ - + ]: 56 : if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
217 : 0 : 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 : 0 : 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 : 56 : walk_state->thread));
232 : :
233 : 56 : status = acpi_ex_acquire_mutex_object((u16)time_desc->integer.value,
234 : : obj_desc,
235 : : walk_state->thread->thread_id);
236 : :
237 [ + - + - ]: 56 : if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) {
238 : :
239 : : /* Save Thread object, original/current sync levels */
240 : :
241 : 56 : obj_desc->mutex.owner_thread = walk_state->thread;
242 : 56 : obj_desc->mutex.original_sync_level =
243 : 56 : walk_state->thread->current_sync_level;
244 : 56 : walk_state->thread->current_sync_level =
245 : 56 : obj_desc->mutex.sync_level;
246 : :
247 : : /* Link the mutex to the current thread for force-unlock at method exit */
248 : :
249 : 56 : 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 : 280 : acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc)
284 : : {
285 : 280 : acpi_status status = AE_OK;
286 : :
287 : 280 : ACPI_FUNCTION_TRACE(ex_release_mutex_object);
288 : :
289 [ + - ]: 280 : 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 : 280 : obj_desc->mutex.acquisition_depth--;
296 [ + - ]: 280 : 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 [ + + ]: 280 : if (obj_desc->mutex.owner_thread) {
304 : :
305 : : /* Unlink the mutex from the owner's list */
306 : :
307 : 56 : acpi_ex_unlink_mutex(obj_desc);
308 : 56 : obj_desc->mutex.owner_thread = NULL;
309 : : }
310 : :
311 : : /* Release the mutex, special case for Global Lock */
312 : :
313 [ + + ]: 280 : if (obj_desc == acpi_gbl_global_lock_mutex) {
314 : 224 : status = acpi_ev_release_global_lock();
315 : : } else {
316 : 56 : acpi_os_release_mutex(obj_desc->mutex.os_mutex);
317 : : }
318 : :
319 : : /* Clear mutex info */
320 : :
321 : 280 : obj_desc->mutex.thread_id = 0;
322 : 280 : 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 : 56 : acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
340 : : struct acpi_walk_state *walk_state)
341 : : {
342 : 56 : u8 previous_sync_level;
343 : 56 : struct acpi_thread_state *owner_thread;
344 : 56 : acpi_status status = AE_OK;
345 : :
346 : 56 : ACPI_FUNCTION_TRACE(ex_release_mutex);
347 : :
348 [ + - ]: 56 : if (!obj_desc) {
349 : : return_ACPI_STATUS(AE_BAD_PARAMETER);
350 : : }
351 : :
352 : 56 : owner_thread = obj_desc->mutex.owner_thread;
353 : :
354 : : /* The mutex must have been previously acquired in order to release it */
355 : :
356 [ - + ]: 56 : if (!owner_thread) {
357 : 0 : ACPI_ERROR((AE_INFO,
358 : : "Cannot release Mutex [%4.4s], not acquired",
359 : : acpi_ut_get_node_name(obj_desc->mutex.node)));
360 : 0 : return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
361 : : }
362 : :
363 : : /* Must have a valid thread ID */
364 : :
365 [ - + ]: 56 : if (!walk_state->thread) {
366 : 0 : ACPI_ERROR((AE_INFO,
367 : : "Cannot release Mutex [%4.4s], null thread info",
368 : : acpi_ut_get_node_name(obj_desc->mutex.node)));
369 : 0 : 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 [ - + ]: 56 : if ((owner_thread->thread_id != walk_state->thread->thread_id) &&
377 [ # # ]: 0 : (obj_desc != acpi_gbl_global_lock_mutex)) {
378 : 0 : 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 : 0 : 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 [ - + ]: 56 : if (obj_desc->mutex.sync_level != owner_thread->current_sync_level) {
394 : 0 : 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 : 0 : 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 : 56 : previous_sync_level =
409 : 56 : 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 : 56 : walk_state->thread));
419 : :
420 : 56 : status = acpi_ex_release_mutex_object(obj_desc);
421 [ + - ]: 56 : if (ACPI_FAILURE(status)) {
422 : : return_ACPI_STATUS(status);
423 : : }
424 : :
425 [ + - ]: 56 : if (obj_desc->mutex.acquisition_depth == 0) {
426 : :
427 : : /* Restore the previous sync_level */
428 : :
429 : 56 : 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 : 4175 : void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
462 : : {
463 : 4175 : union acpi_operand_object *next = thread->acquired_mutex_list;
464 : 4175 : union acpi_operand_object *obj_desc;
465 : :
466 : 4175 : ACPI_FUNCTION_TRACE(ex_release_all_mutexes);
467 : :
468 : : /* Traverse the list of owned mutexes, releasing each one */
469 : :
470 [ - + ]: 4175 : while (next) {
471 : 0 : 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 : 0 : obj_desc->mutex.acquisition_depth));
477 : :
478 : : /* Release the mutex, special case for Global Lock */
479 : :
480 [ # # ]: 0 : if (obj_desc == acpi_gbl_global_lock_mutex) {
481 : :
482 : : /* Ignore errors */
483 : :
484 : 0 : (void)acpi_ev_release_global_lock();
485 : : } else {
486 : 0 : acpi_os_release_mutex(obj_desc->mutex.os_mutex);
487 : : }
488 : :
489 : : /* Update Thread sync_level (Last mutex is the important one) */
490 : :
491 : 0 : thread->current_sync_level =
492 : 0 : obj_desc->mutex.original_sync_level;
493 : :
494 : : /* Mark mutex unowned */
495 : :
496 : 0 : next = obj_desc->mutex.next;
497 : :
498 : 0 : obj_desc->mutex.prev = NULL;
499 : 0 : obj_desc->mutex.next = NULL;
500 : 0 : obj_desc->mutex.acquisition_depth = 0;
501 : 0 : obj_desc->mutex.owner_thread = NULL;
502 : 0 : obj_desc->mutex.thread_id = 0;
503 : : }
504 : :
505 : 4175 : return_VOID;
506 : : }
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