1/******************************************************************************
2 *
3 * Module Name: exmutex - ASL Mutex Acquire/Release functions
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2015, Intel Corp.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions, and the following disclaimer,
16 *    without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 *    substantially similar to the "NO WARRANTY" disclaimer below
19 *    ("Disclaimer") and any redistribution must be conditioned upon
20 *    including a substantially similar Disclaimer requirement for further
21 *    binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 *    of any contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44#include <acpi/acpi.h>
45#include "accommon.h"
46#include "acinterp.h"
47#include "acevents.h"
48
49#define _COMPONENT          ACPI_EXECUTER
50ACPI_MODULE_NAME("exmutex")
51
52/* Local prototypes */
53static void
54acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
55		   struct acpi_thread_state *thread);
56
57/*******************************************************************************
58 *
59 * FUNCTION:    acpi_ex_unlink_mutex
60 *
61 * PARAMETERS:  obj_desc            - The mutex to be unlinked
62 *
63 * RETURN:      None
64 *
65 * DESCRIPTION: Remove a mutex from the "AcquiredMutex" list
66 *
67 ******************************************************************************/
68
69void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
70{
71	struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;
72
73	if (!thread) {
74		return;
75	}
76
77	/* Doubly linked list */
78
79	if (obj_desc->mutex.next) {
80		(obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
81	}
82
83	if (obj_desc->mutex.prev) {
84		(obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
85
86		/*
87		 * Migrate the previous sync level associated with this mutex to
88		 * the previous mutex on the list so that it may be preserved.
89		 * This handles the case where several mutexes have been acquired
90		 * at the same level, but are not released in opposite order.
91		 */
92		(obj_desc->mutex.prev)->mutex.original_sync_level =
93		    obj_desc->mutex.original_sync_level;
94	} else {
95		thread->acquired_mutex_list = obj_desc->mutex.next;
96	}
97}
98
99/*******************************************************************************
100 *
101 * FUNCTION:    acpi_ex_link_mutex
102 *
103 * PARAMETERS:  obj_desc            - The mutex to be linked
104 *              thread              - Current executing thread object
105 *
106 * RETURN:      None
107 *
108 * DESCRIPTION: Add a mutex to the "AcquiredMutex" list for this walk
109 *
110 ******************************************************************************/
111
112static void
113acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
114		   struct acpi_thread_state *thread)
115{
116	union acpi_operand_object *list_head;
117
118	list_head = thread->acquired_mutex_list;
119
120	/* This object will be the first object in the list */
121
122	obj_desc->mutex.prev = NULL;
123	obj_desc->mutex.next = list_head;
124
125	/* Update old first object to point back to this object */
126
127	if (list_head) {
128		list_head->mutex.prev = obj_desc;
129	}
130
131	/* Update list head */
132
133	thread->acquired_mutex_list = obj_desc;
134}
135
136/*******************************************************************************
137 *
138 * FUNCTION:    acpi_ex_acquire_mutex_object
139 *
140 * PARAMETERS:  timeout             - Timeout in milliseconds
141 *              obj_desc            - Mutex object
142 *              thread_id           - Current thread state
143 *
144 * RETURN:      Status
145 *
146 * DESCRIPTION: Acquire an AML mutex, low-level interface. Provides a common
147 *              path that supports multiple acquires by the same thread.
148 *
149 * MUTEX:       Interpreter must be locked
150 *
151 * NOTE: This interface is called from three places:
152 * 1) From acpi_ex_acquire_mutex, via an AML Acquire() operator
153 * 2) From acpi_ex_acquire_global_lock when an AML Field access requires the
154 *    global lock
155 * 3) From the external interface, acpi_acquire_global_lock
156 *
157 ******************************************************************************/
158
159acpi_status
160acpi_ex_acquire_mutex_object(u16 timeout,
161			     union acpi_operand_object *obj_desc,
162			     acpi_thread_id thread_id)
163{
164	acpi_status status;
165
166	ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex_object, obj_desc);
167
168	if (!obj_desc) {
169		return_ACPI_STATUS(AE_BAD_PARAMETER);
170	}
171
172	/* Support for multiple acquires by the owning thread */
173
174	if (obj_desc->mutex.thread_id == thread_id) {
175		/*
176		 * The mutex is already owned by this thread, just increment the
177		 * acquisition depth
178		 */
179		obj_desc->mutex.acquisition_depth++;
180		return_ACPI_STATUS(AE_OK);
181	}
182
183	/* Acquire the mutex, wait if necessary. Special case for Global Lock */
184
185	if (obj_desc == acpi_gbl_global_lock_mutex) {
186		status = acpi_ev_acquire_global_lock(timeout);
187	} else {
188		status = acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex,
189						   timeout);
190	}
191
192	if (ACPI_FAILURE(status)) {
193
194		/* Includes failure from a timeout on time_desc */
195
196		return_ACPI_STATUS(status);
197	}
198
199	/* Acquired the mutex: update mutex object */
200
201	obj_desc->mutex.thread_id = thread_id;
202	obj_desc->mutex.acquisition_depth = 1;
203	obj_desc->mutex.original_sync_level = 0;
204	obj_desc->mutex.owner_thread = NULL;	/* Used only for AML Acquire() */
205
206	return_ACPI_STATUS(AE_OK);
207}
208
209/*******************************************************************************
210 *
211 * FUNCTION:    acpi_ex_acquire_mutex
212 *
213 * PARAMETERS:  time_desc           - Timeout integer
214 *              obj_desc            - Mutex object
215 *              walk_state          - Current method execution state
216 *
217 * RETURN:      Status
218 *
219 * DESCRIPTION: Acquire an AML mutex
220 *
221 ******************************************************************************/
222
223acpi_status
224acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
225		      union acpi_operand_object *obj_desc,
226		      struct acpi_walk_state *walk_state)
227{
228	acpi_status status;
229
230	ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc);
231
232	if (!obj_desc) {
233		return_ACPI_STATUS(AE_BAD_PARAMETER);
234	}
235
236	/* Must have a valid thread state struct */
237
238	if (!walk_state->thread) {
239		ACPI_ERROR((AE_INFO,
240			    "Cannot acquire Mutex [%4.4s], null thread info",
241			    acpi_ut_get_node_name(obj_desc->mutex.node)));
242		return_ACPI_STATUS(AE_AML_INTERNAL);
243	}
244
245	/*
246	 * Current sync level must be less than or equal to the sync level of the
247	 * mutex. This mechanism provides some deadlock prevention
248	 */
249	if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
250		ACPI_ERROR((AE_INFO,
251			    "Cannot acquire Mutex [%4.4s], current SyncLevel is too large (%u)",
252			    acpi_ut_get_node_name(obj_desc->mutex.node),
253			    walk_state->thread->current_sync_level));
254		return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
255	}
256
257	status = acpi_ex_acquire_mutex_object((u16) time_desc->integer.value,
258					      obj_desc,
259					      walk_state->thread->thread_id);
260	if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) {
261
262		/* Save Thread object, original/current sync levels */
263
264		obj_desc->mutex.owner_thread = walk_state->thread;
265		obj_desc->mutex.original_sync_level =
266		    walk_state->thread->current_sync_level;
267		walk_state->thread->current_sync_level =
268		    obj_desc->mutex.sync_level;
269
270		/* Link the mutex to the current thread for force-unlock at method exit */
271
272		acpi_ex_link_mutex(obj_desc, walk_state->thread);
273	}
274
275	return_ACPI_STATUS(status);
276}
277
278/*******************************************************************************
279 *
280 * FUNCTION:    acpi_ex_release_mutex_object
281 *
282 * PARAMETERS:  obj_desc            - The object descriptor for this op
283 *
284 * RETURN:      Status
285 *
286 * DESCRIPTION: Release a previously acquired Mutex, low level interface.
287 *              Provides a common path that supports multiple releases (after
288 *              previous multiple acquires) by the same thread.
289 *
290 * MUTEX:       Interpreter must be locked
291 *
292 * NOTE: This interface is called from three places:
293 * 1) From acpi_ex_release_mutex, via an AML Acquire() operator
294 * 2) From acpi_ex_release_global_lock when an AML Field access requires the
295 *    global lock
296 * 3) From the external interface, acpi_release_global_lock
297 *
298 ******************************************************************************/
299
300acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc)
301{
302	acpi_status status = AE_OK;
303
304	ACPI_FUNCTION_TRACE(ex_release_mutex_object);
305
306	if (obj_desc->mutex.acquisition_depth == 0) {
307		return_ACPI_STATUS(AE_NOT_ACQUIRED);
308	}
309
310	/* Match multiple Acquires with multiple Releases */
311
312	obj_desc->mutex.acquisition_depth--;
313	if (obj_desc->mutex.acquisition_depth != 0) {
314
315		/* Just decrement the depth and return */
316
317		return_ACPI_STATUS(AE_OK);
318	}
319
320	if (obj_desc->mutex.owner_thread) {
321
322		/* Unlink the mutex from the owner's list */
323
324		acpi_ex_unlink_mutex(obj_desc);
325		obj_desc->mutex.owner_thread = NULL;
326	}
327
328	/* Release the mutex, special case for Global Lock */
329
330	if (obj_desc == acpi_gbl_global_lock_mutex) {
331		status = acpi_ev_release_global_lock();
332	} else {
333		acpi_os_release_mutex(obj_desc->mutex.os_mutex);
334	}
335
336	/* Clear mutex info */
337
338	obj_desc->mutex.thread_id = 0;
339	return_ACPI_STATUS(status);
340}
341
342/*******************************************************************************
343 *
344 * FUNCTION:    acpi_ex_release_mutex
345 *
346 * PARAMETERS:  obj_desc            - The object descriptor for this op
347 *              walk_state          - Current method execution state
348 *
349 * RETURN:      Status
350 *
351 * DESCRIPTION: Release a previously acquired Mutex.
352 *
353 ******************************************************************************/
354
355acpi_status
356acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
357		      struct acpi_walk_state *walk_state)
358{
359	acpi_status status = AE_OK;
360	u8 previous_sync_level;
361	struct acpi_thread_state *owner_thread;
362
363	ACPI_FUNCTION_TRACE(ex_release_mutex);
364
365	if (!obj_desc) {
366		return_ACPI_STATUS(AE_BAD_PARAMETER);
367	}
368
369	owner_thread = obj_desc->mutex.owner_thread;
370
371	/* The mutex must have been previously acquired in order to release it */
372
373	if (!owner_thread) {
374		ACPI_ERROR((AE_INFO,
375			    "Cannot release Mutex [%4.4s], not acquired",
376			    acpi_ut_get_node_name(obj_desc->mutex.node)));
377		return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
378	}
379
380	/* Must have a valid thread ID */
381
382	if (!walk_state->thread) {
383		ACPI_ERROR((AE_INFO,
384			    "Cannot release Mutex [%4.4s], null thread info",
385			    acpi_ut_get_node_name(obj_desc->mutex.node)));
386		return_ACPI_STATUS(AE_AML_INTERNAL);
387	}
388
389	/*
390	 * The Mutex is owned, but this thread must be the owner.
391	 * Special case for Global Lock, any thread can release
392	 */
393	if ((owner_thread->thread_id != walk_state->thread->thread_id) &&
394	    (obj_desc != acpi_gbl_global_lock_mutex)) {
395		ACPI_ERROR((AE_INFO,
396			    "Thread %u cannot release Mutex [%4.4s] acquired by thread %u",
397			    (u32)walk_state->thread->thread_id,
398			    acpi_ut_get_node_name(obj_desc->mutex.node),
399			    (u32)owner_thread->thread_id));
400		return_ACPI_STATUS(AE_AML_NOT_OWNER);
401	}
402
403	/*
404	 * The sync level of the mutex must be equal to the current sync level. In
405	 * other words, the current level means that at least one mutex at that
406	 * level is currently being held. Attempting to release a mutex of a
407	 * different level can only mean that the mutex ordering rule is being
408	 * violated. This behavior is clarified in ACPI 4.0 specification.
409	 */
410	if (obj_desc->mutex.sync_level != owner_thread->current_sync_level) {
411		ACPI_ERROR((AE_INFO,
412			    "Cannot release Mutex [%4.4s], SyncLevel mismatch: mutex %u current %u",
413			    acpi_ut_get_node_name(obj_desc->mutex.node),
414			    obj_desc->mutex.sync_level,
415			    walk_state->thread->current_sync_level));
416		return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
417	}
418
419	/*
420	 * Get the previous sync_level from the head of the acquired mutex list.
421	 * This handles the case where several mutexes at the same level have been
422	 * acquired, but are not released in reverse order.
423	 */
424	previous_sync_level =
425	    owner_thread->acquired_mutex_list->mutex.original_sync_level;
426
427	status = acpi_ex_release_mutex_object(obj_desc);
428	if (ACPI_FAILURE(status)) {
429		return_ACPI_STATUS(status);
430	}
431
432	if (obj_desc->mutex.acquisition_depth == 0) {
433
434		/* Restore the previous sync_level */
435
436		owner_thread->current_sync_level = previous_sync_level;
437	}
438
439	return_ACPI_STATUS(status);
440}
441
442/*******************************************************************************
443 *
444 * FUNCTION:    acpi_ex_release_all_mutexes
445 *
446 * PARAMETERS:  thread              - Current executing thread object
447 *
448 * RETURN:      Status
449 *
450 * DESCRIPTION: Release all mutexes held by this thread
451 *
452 * NOTE: This function is called as the thread is exiting the interpreter.
453 * Mutexes are not released when an individual control method is exited, but
454 * only when the parent thread actually exits the interpreter. This allows one
455 * method to acquire a mutex, and a different method to release it, as long as
456 * this is performed underneath a single parent control method.
457 *
458 ******************************************************************************/
459
460void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
461{
462	union acpi_operand_object *next = thread->acquired_mutex_list;
463	union acpi_operand_object *obj_desc;
464
465	ACPI_FUNCTION_NAME(ex_release_all_mutexes);
466
467	/* Traverse the list of owned mutexes, releasing each one */
468
469	while (next) {
470		obj_desc = next;
471		next = obj_desc->mutex.next;
472
473		obj_desc->mutex.prev = NULL;
474		obj_desc->mutex.next = NULL;
475		obj_desc->mutex.acquisition_depth = 0;
476
477		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
478				  "Force-releasing held mutex: %p\n",
479				  obj_desc));
480
481		/* Release the mutex, special case for Global Lock */
482
483		if (obj_desc == acpi_gbl_global_lock_mutex) {
484
485			/* Ignore errors */
486
487			(void)acpi_ev_release_global_lock();
488		} else {
489			acpi_os_release_mutex(obj_desc->mutex.os_mutex);
490		}
491
492		/* Mark mutex unowned */
493
494		obj_desc->mutex.owner_thread = NULL;
495		obj_desc->mutex.thread_id = 0;
496
497		/* Update Thread sync_level (Last mutex is the important one) */
498
499		thread->current_sync_level =
500		    obj_desc->mutex.original_sync_level;
501	}
502}
503