Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
[sfrench/cifs-2.6.git] / drivers / acpi / acpica / exmutex.c
1
2 /******************************************************************************
3  *
4  * Module Name: exmutex - ASL Mutex Acquire/Release functions
5  *
6  *****************************************************************************/
7
8 /*
9  * Copyright (C) 2000 - 2010, Intel Corp.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44
45 #include <acpi/acpi.h>
46 #include "accommon.h"
47 #include "acinterp.h"
48 #include "acevents.h"
49
50 #define _COMPONENT          ACPI_EXECUTER
51 ACPI_MODULE_NAME("exmutex")
52
53 /* Local prototypes */
54 static void
55 acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
56                    struct acpi_thread_state *thread);
57
58 /*******************************************************************************
59  *
60  * FUNCTION:    acpi_ex_unlink_mutex
61  *
62  * PARAMETERS:  obj_desc            - The mutex to be unlinked
63  *
64  * RETURN:      None
65  *
66  * DESCRIPTION: Remove a mutex from the "AcquiredMutex" list
67  *
68  ******************************************************************************/
69
70 void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
71 {
72         struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;
73
74         if (!thread) {
75                 return;
76         }
77
78         /* Doubly linked list */
79
80         if (obj_desc->mutex.next) {
81                 (obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
82         }
83
84         if (obj_desc->mutex.prev) {
85                 (obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
86
87                 /*
88                  * Migrate the previous sync level associated with this mutex to the
89                  * previous mutex on the list so that it may be preserved. This handles
90                  * the case where several mutexes have been acquired at the same level,
91                  * but are not released in opposite order.
92                  */
93                 (obj_desc->mutex.prev)->mutex.original_sync_level =
94                     obj_desc->mutex.original_sync_level;
95         } else {
96                 thread->acquired_mutex_list = obj_desc->mutex.next;
97         }
98 }
99
100 /*******************************************************************************
101  *
102  * FUNCTION:    acpi_ex_link_mutex
103  *
104  * PARAMETERS:  obj_desc        - The mutex to be linked
105  *              Thread          - Current executing thread object
106  *
107  * RETURN:      None
108  *
109  * DESCRIPTION: Add a mutex to the "AcquiredMutex" list for this walk
110  *
111  ******************************************************************************/
112
113 static void
114 acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
115                    struct acpi_thread_state *thread)
116 {
117         union acpi_operand_object *list_head;
118
119         list_head = thread->acquired_mutex_list;
120
121         /* This object will be the first object in the list */
122
123         obj_desc->mutex.prev = NULL;
124         obj_desc->mutex.next = list_head;
125
126         /* Update old first object to point back to this object */
127
128         if (list_head) {
129                 list_head->mutex.prev = obj_desc;
130         }
131
132         /* Update list head */
133
134         thread->acquired_mutex_list = obj_desc;
135 }
136
137 /*******************************************************************************
138  *
139  * FUNCTION:    acpi_ex_acquire_mutex_object
140  *
141  * PARAMETERS:  time_desc           - Timeout in milliseconds
142  *              obj_desc            - Mutex object
143  *              Thread              - Current thread state
144  *
145  * RETURN:      Status
146  *
147  * DESCRIPTION: Acquire an AML mutex, low-level interface. Provides a common
148  *              path that supports multiple acquires by the same thread.
149  *
150  * MUTEX:       Interpreter must be locked
151  *
152  * NOTE: This interface is called from three places:
153  * 1) From acpi_ex_acquire_mutex, via an AML Acquire() operator
154  * 2) From acpi_ex_acquire_global_lock when an AML Field access requires the
155  *    global lock
156  * 3) From the external interface, acpi_acquire_global_lock
157  *
158  ******************************************************************************/
159
160 acpi_status
161 acpi_ex_acquire_mutex_object(u16 timeout,
162                              union acpi_operand_object *obj_desc,
163                              acpi_thread_id thread_id)
164 {
165         acpi_status status;
166
167         ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex_object, obj_desc);
168
169         if (!obj_desc) {
170                 return_ACPI_STATUS(AE_BAD_PARAMETER);
171         }
172
173         /* Support for multiple acquires by the owning thread */
174
175         if (obj_desc->mutex.thread_id == thread_id) {
176                 /*
177                  * The mutex is already owned by this thread, just increment the
178                  * acquisition depth
179                  */
180                 obj_desc->mutex.acquisition_depth++;
181                 return_ACPI_STATUS(AE_OK);
182         }
183
184         /* Acquire the mutex, wait if necessary. Special case for Global Lock */
185
186         if (obj_desc == acpi_gbl_global_lock_mutex) {
187                 status = acpi_ev_acquire_global_lock(timeout);
188         } else {
189                 status = acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex,
190                                                    timeout);
191         }
192
193         if (ACPI_FAILURE(status)) {
194
195                 /* Includes failure from a timeout on time_desc */
196
197                 return_ACPI_STATUS(status);
198         }
199
200         /* Acquired the mutex: update mutex object */
201
202         obj_desc->mutex.thread_id = thread_id;
203         obj_desc->mutex.acquisition_depth = 1;
204         obj_desc->mutex.original_sync_level = 0;
205         obj_desc->mutex.owner_thread = NULL;    /* Used only for AML Acquire() */
206
207         return_ACPI_STATUS(AE_OK);
208 }
209
210 /*******************************************************************************
211  *
212  * FUNCTION:    acpi_ex_acquire_mutex
213  *
214  * PARAMETERS:  time_desc           - Timeout integer
215  *              obj_desc            - Mutex object
216  *              walk_state          - Current method execution state
217  *
218  * RETURN:      Status
219  *
220  * DESCRIPTION: Acquire an AML mutex
221  *
222  ******************************************************************************/
223
224 acpi_status
225 acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
226                       union acpi_operand_object *obj_desc,
227                       struct acpi_walk_state *walk_state)
228 {
229         acpi_status status;
230
231         ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc);
232
233         if (!obj_desc) {
234                 return_ACPI_STATUS(AE_BAD_PARAMETER);
235         }
236
237         /* Must have a valid thread ID */
238
239         if (!walk_state->thread) {
240                 ACPI_ERROR((AE_INFO,
241                             "Cannot acquire Mutex [%4.4s], null thread info",
242                             acpi_ut_get_node_name(obj_desc->mutex.node)));
243                 return_ACPI_STATUS(AE_AML_INTERNAL);
244         }
245
246         /*
247          * Current sync level must be less than or equal to the sync level of the
248          * mutex. This mechanism provides some deadlock prevention
249          */
250         if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
251                 ACPI_ERROR((AE_INFO,
252                             "Cannot acquire Mutex [%4.4s], current SyncLevel is too large (%d)",
253                             acpi_ut_get_node_name(obj_desc->mutex.node),
254                             walk_state->thread->current_sync_level));
255                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
256         }
257
258         status = acpi_ex_acquire_mutex_object((u16) time_desc->integer.value,
259                                               obj_desc,
260                                               walk_state->thread->thread_id);
261         if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) {
262
263                 /* Save Thread object, original/current sync levels */
264
265                 obj_desc->mutex.owner_thread = walk_state->thread;
266                 obj_desc->mutex.original_sync_level =
267                     walk_state->thread->current_sync_level;
268                 walk_state->thread->current_sync_level =
269                     obj_desc->mutex.sync_level;
270
271                 /* Link the mutex to the current thread for force-unlock at method exit */
272
273                 acpi_ex_link_mutex(obj_desc, walk_state->thread);
274         }
275
276         return_ACPI_STATUS(status);
277 }
278
279 /*******************************************************************************
280  *
281  * FUNCTION:    acpi_ex_release_mutex_object
282  *
283  * PARAMETERS:  obj_desc            - The object descriptor for this op
284  *
285  * RETURN:      Status
286  *
287  * DESCRIPTION: Release a previously acquired Mutex, low level interface.
288  *              Provides a common path that supports multiple releases (after
289  *              previous multiple acquires) by the same thread.
290  *
291  * MUTEX:       Interpreter must be locked
292  *
293  * NOTE: This interface is called from three places:
294  * 1) From acpi_ex_release_mutex, via an AML Acquire() operator
295  * 2) From acpi_ex_release_global_lock when an AML Field access requires the
296  *    global lock
297  * 3) From the external interface, acpi_release_global_lock
298  *
299  ******************************************************************************/
300
301 acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc)
302 {
303         acpi_status status = AE_OK;
304
305         ACPI_FUNCTION_TRACE(ex_release_mutex_object);
306
307         if (obj_desc->mutex.acquisition_depth == 0) {
308                 return (AE_NOT_ACQUIRED);
309         }
310
311         /* Match multiple Acquires with multiple Releases */
312
313         obj_desc->mutex.acquisition_depth--;
314         if (obj_desc->mutex.acquisition_depth != 0) {
315
316                 /* Just decrement the depth and return */
317
318                 return_ACPI_STATUS(AE_OK);
319         }
320
321         if (obj_desc->mutex.owner_thread) {
322
323                 /* Unlink the mutex from the owner's list */
324
325                 acpi_ex_unlink_mutex(obj_desc);
326                 obj_desc->mutex.owner_thread = NULL;
327         }
328
329         /* Release the mutex, special case for Global Lock */
330
331         if (obj_desc == acpi_gbl_global_lock_mutex) {
332                 status = acpi_ev_release_global_lock();
333         } else {
334                 acpi_os_release_mutex(obj_desc->mutex.os_mutex);
335         }
336
337         /* Clear mutex info */
338
339         obj_desc->mutex.thread_id = NULL;
340         return_ACPI_STATUS(status);
341 }
342
343 /*******************************************************************************
344  *
345  * FUNCTION:    acpi_ex_release_mutex
346  *
347  * PARAMETERS:  obj_desc            - The object descriptor for this op
348  *              walk_state          - Current method execution state
349  *
350  * RETURN:      Status
351  *
352  * DESCRIPTION: Release a previously acquired Mutex.
353  *
354  ******************************************************************************/
355
356 acpi_status
357 acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
358                       struct acpi_walk_state *walk_state)
359 {
360         acpi_status status = AE_OK;
361         u8 previous_sync_level;
362
363         ACPI_FUNCTION_TRACE(ex_release_mutex);
364
365         if (!obj_desc) {
366                 return_ACPI_STATUS(AE_BAD_PARAMETER);
367         }
368
369         /* The mutex must have been previously acquired in order to release it */
370
371         if (!obj_desc->mutex.owner_thread) {
372                 ACPI_ERROR((AE_INFO,
373                             "Cannot release Mutex [%4.4s], not acquired",
374                             acpi_ut_get_node_name(obj_desc->mutex.node)));
375                 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
376         }
377
378         /* Must have a valid thread. */
379         if (!walk_state->thread) {
380                 ACPI_ERROR((AE_INFO,
381                             "Cannot release Mutex [%4.4s], null thread info",
382                             acpi_ut_get_node_name(obj_desc->mutex.node)));
383                 return_ACPI_STATUS(AE_AML_INTERNAL);
384         }
385
386         /*
387          * The Mutex is owned, but this thread must be the owner.
388          * Special case for Global Lock, any thread can release
389          */
390         if ((obj_desc->mutex.owner_thread->thread_id !=
391              walk_state->thread->thread_id)
392             && (obj_desc != acpi_gbl_global_lock_mutex)) {
393                 ACPI_ERROR((AE_INFO,
394                             "Thread %p cannot release Mutex [%4.4s] acquired by thread %p",
395                             ACPI_CAST_PTR(void, walk_state->thread->thread_id),
396                             acpi_ut_get_node_name(obj_desc->mutex.node),
397                             ACPI_CAST_PTR(void,
398                                           obj_desc->mutex.owner_thread->
399                                           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 !=
411             walk_state->thread->current_sync_level) {
412                 ACPI_ERROR((AE_INFO,
413                             "Cannot release Mutex [%4.4s], SyncLevel mismatch: mutex %d current %d",
414                             acpi_ut_get_node_name(obj_desc->mutex.node),
415                             obj_desc->mutex.sync_level,
416                             walk_state->thread->current_sync_level));
417                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
418         }
419
420         /*
421          * Get the previous sync_level from the head of the acquired mutex list.
422          * This handles the case where several mutexes at the same level have been
423          * acquired, but are not released in reverse order.
424          */
425         previous_sync_level =
426             walk_state->thread->acquired_mutex_list->mutex.original_sync_level;
427
428         status = acpi_ex_release_mutex_object(obj_desc);
429         if (ACPI_FAILURE(status)) {
430                 return_ACPI_STATUS(status);
431         }
432
433         if (obj_desc->mutex.acquisition_depth == 0) {
434
435                 /* Restore the previous sync_level */
436
437                 walk_state->thread->current_sync_level = previous_sync_level;
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
460 void 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_ENTRY();
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                 /* Release the mutex, special case for Global Lock */
478
479                 if (obj_desc == acpi_gbl_global_lock_mutex) {
480
481                         /* Ignore errors */
482
483                         (void)acpi_ev_release_global_lock();
484                 } else {
485                         acpi_os_release_mutex(obj_desc->mutex.os_mutex);
486                 }
487
488                 /* Mark mutex unowned */
489
490                 obj_desc->mutex.owner_thread = NULL;
491                 obj_desc->mutex.thread_id = NULL;
492
493                 /* Update Thread sync_level (Last mutex is the important one) */
494
495                 thread->current_sync_level =
496                     obj_desc->mutex.original_sync_level;
497         }
498 }