Merge branch 'master' of /repos/git/net-2.6
[linux-2.6] / 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 - 2008, 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         } else {
87                 thread->acquired_mutex_list = obj_desc->mutex.next;
88         }
89 }
90
91 /*******************************************************************************
92  *
93  * FUNCTION:    acpi_ex_link_mutex
94  *
95  * PARAMETERS:  obj_desc        - The mutex to be linked
96  *              Thread          - Current executing thread object
97  *
98  * RETURN:      None
99  *
100  * DESCRIPTION: Add a mutex to the "AcquiredMutex" list for this walk
101  *
102  ******************************************************************************/
103
104 static void
105 acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
106                    struct acpi_thread_state *thread)
107 {
108         union acpi_operand_object *list_head;
109
110         list_head = thread->acquired_mutex_list;
111
112         /* This object will be the first object in the list */
113
114         obj_desc->mutex.prev = NULL;
115         obj_desc->mutex.next = list_head;
116
117         /* Update old first object to point back to this object */
118
119         if (list_head) {
120                 list_head->mutex.prev = obj_desc;
121         }
122
123         /* Update list head */
124
125         thread->acquired_mutex_list = obj_desc;
126 }
127
128 /*******************************************************************************
129  *
130  * FUNCTION:    acpi_ex_acquire_mutex_object
131  *
132  * PARAMETERS:  time_desc           - Timeout in milliseconds
133  *              obj_desc            - Mutex object
134  *              Thread              - Current thread state
135  *
136  * RETURN:      Status
137  *
138  * DESCRIPTION: Acquire an AML mutex, low-level interface. Provides a common
139  *              path that supports multiple acquires by the same thread.
140  *
141  * MUTEX:       Interpreter must be locked
142  *
143  * NOTE: This interface is called from three places:
144  * 1) From acpi_ex_acquire_mutex, via an AML Acquire() operator
145  * 2) From acpi_ex_acquire_global_lock when an AML Field access requires the
146  *    global lock
147  * 3) From the external interface, acpi_acquire_global_lock
148  *
149  ******************************************************************************/
150
151 acpi_status
152 acpi_ex_acquire_mutex_object(u16 timeout,
153                              union acpi_operand_object *obj_desc,
154                              acpi_thread_id thread_id)
155 {
156         acpi_status status;
157
158         ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex_object, obj_desc);
159
160         if (!obj_desc) {
161                 return_ACPI_STATUS(AE_BAD_PARAMETER);
162         }
163
164         /* Support for multiple acquires by the owning thread */
165
166         if (obj_desc->mutex.thread_id == thread_id) {
167                 /*
168                  * The mutex is already owned by this thread, just increment the
169                  * acquisition depth
170                  */
171                 obj_desc->mutex.acquisition_depth++;
172                 return_ACPI_STATUS(AE_OK);
173         }
174
175         /* Acquire the mutex, wait if necessary. Special case for Global Lock */
176
177         if (obj_desc == acpi_gbl_global_lock_mutex) {
178                 status = acpi_ev_acquire_global_lock(timeout);
179         } else {
180                 status = acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex,
181                                                    timeout);
182         }
183
184         if (ACPI_FAILURE(status)) {
185
186                 /* Includes failure from a timeout on time_desc */
187
188                 return_ACPI_STATUS(status);
189         }
190
191         /* Acquired the mutex: update mutex object */
192
193         obj_desc->mutex.thread_id = thread_id;
194         obj_desc->mutex.acquisition_depth = 1;
195         obj_desc->mutex.original_sync_level = 0;
196         obj_desc->mutex.owner_thread = NULL;    /* Used only for AML Acquire() */
197
198         return_ACPI_STATUS(AE_OK);
199 }
200
201 /*******************************************************************************
202  *
203  * FUNCTION:    acpi_ex_acquire_mutex
204  *
205  * PARAMETERS:  time_desc           - Timeout integer
206  *              obj_desc            - Mutex object
207  *              walk_state          - Current method execution state
208  *
209  * RETURN:      Status
210  *
211  * DESCRIPTION: Acquire an AML mutex
212  *
213  ******************************************************************************/
214
215 acpi_status
216 acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
217                       union acpi_operand_object *obj_desc,
218                       struct acpi_walk_state *walk_state)
219 {
220         acpi_status status;
221
222         ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc);
223
224         if (!obj_desc) {
225                 return_ACPI_STATUS(AE_BAD_PARAMETER);
226         }
227
228         /* Must have a valid thread ID */
229
230         if (!walk_state->thread) {
231                 ACPI_ERROR((AE_INFO,
232                             "Cannot acquire Mutex [%4.4s], null thread info",
233                             acpi_ut_get_node_name(obj_desc->mutex.node)));
234                 return_ACPI_STATUS(AE_AML_INTERNAL);
235         }
236
237         /*
238          * Current sync level must be less than or equal to the sync level of the
239          * mutex. This mechanism provides some deadlock prevention
240          */
241         if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
242                 ACPI_ERROR((AE_INFO,
243                             "Cannot acquire Mutex [%4.4s], current SyncLevel is too large (%d)",
244                             acpi_ut_get_node_name(obj_desc->mutex.node),
245                             walk_state->thread->current_sync_level));
246                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
247         }
248
249         status = acpi_ex_acquire_mutex_object((u16) time_desc->integer.value,
250                                               obj_desc,
251                                               walk_state->thread->thread_id);
252         if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) {
253
254                 /* Save Thread object, original/current sync levels */
255
256                 obj_desc->mutex.owner_thread = walk_state->thread;
257                 obj_desc->mutex.original_sync_level =
258                     walk_state->thread->current_sync_level;
259                 walk_state->thread->current_sync_level =
260                     obj_desc->mutex.sync_level;
261
262                 /* Link the mutex to the current thread for force-unlock at method exit */
263
264                 acpi_ex_link_mutex(obj_desc, walk_state->thread);
265         }
266
267         return_ACPI_STATUS(status);
268 }
269
270 /*******************************************************************************
271  *
272  * FUNCTION:    acpi_ex_release_mutex_object
273  *
274  * PARAMETERS:  obj_desc            - The object descriptor for this op
275  *
276  * RETURN:      Status
277  *
278  * DESCRIPTION: Release a previously acquired Mutex, low level interface.
279  *              Provides a common path that supports multiple releases (after
280  *              previous multiple acquires) by the same thread.
281  *
282  * MUTEX:       Interpreter must be locked
283  *
284  * NOTE: This interface is called from three places:
285  * 1) From acpi_ex_release_mutex, via an AML Acquire() operator
286  * 2) From acpi_ex_release_global_lock when an AML Field access requires the
287  *    global lock
288  * 3) From the external interface, acpi_release_global_lock
289  *
290  ******************************************************************************/
291
292 acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc)
293 {
294         acpi_status status = AE_OK;
295
296         ACPI_FUNCTION_TRACE(ex_release_mutex_object);
297
298         if (obj_desc->mutex.acquisition_depth == 0) {
299                 return (AE_NOT_ACQUIRED);
300         }
301
302         /* Match multiple Acquires with multiple Releases */
303
304         obj_desc->mutex.acquisition_depth--;
305         if (obj_desc->mutex.acquisition_depth != 0) {
306
307                 /* Just decrement the depth and return */
308
309                 return_ACPI_STATUS(AE_OK);
310         }
311
312         if (obj_desc->mutex.owner_thread) {
313
314                 /* Unlink the mutex from the owner's list */
315
316                 acpi_ex_unlink_mutex(obj_desc);
317                 obj_desc->mutex.owner_thread = NULL;
318         }
319
320         /* Release the mutex, special case for Global Lock */
321
322         if (obj_desc == acpi_gbl_global_lock_mutex) {
323                 status = acpi_ev_release_global_lock();
324         } else {
325                 acpi_os_release_mutex(obj_desc->mutex.os_mutex);
326         }
327
328         /* Clear mutex info */
329
330         obj_desc->mutex.thread_id = NULL;
331         return_ACPI_STATUS(status);
332 }
333
334 /*******************************************************************************
335  *
336  * FUNCTION:    acpi_ex_release_mutex
337  *
338  * PARAMETERS:  obj_desc            - The object descriptor for this op
339  *              walk_state          - Current method execution state
340  *
341  * RETURN:      Status
342  *
343  * DESCRIPTION: Release a previously acquired Mutex.
344  *
345  ******************************************************************************/
346
347 acpi_status
348 acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
349                       struct acpi_walk_state *walk_state)
350 {
351         acpi_status status = AE_OK;
352
353         ACPI_FUNCTION_TRACE(ex_release_mutex);
354
355         if (!obj_desc) {
356                 return_ACPI_STATUS(AE_BAD_PARAMETER);
357         }
358
359         /* The mutex must have been previously acquired in order to release it */
360
361         if (!obj_desc->mutex.owner_thread) {
362                 ACPI_ERROR((AE_INFO,
363                             "Cannot release Mutex [%4.4s], not acquired",
364                             acpi_ut_get_node_name(obj_desc->mutex.node)));
365                 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
366         }
367
368         /*
369          * The Mutex is owned, but this thread must be the owner.
370          * Special case for Global Lock, any thread can release
371          */
372         if ((obj_desc->mutex.owner_thread->thread_id !=
373              walk_state->thread->thread_id)
374             && (obj_desc != acpi_gbl_global_lock_mutex)) {
375                 ACPI_ERROR((AE_INFO,
376                             "Thread %lX cannot release Mutex [%4.4s] acquired by thread %lX",
377                             (unsigned long)walk_state->thread->thread_id,
378                             acpi_ut_get_node_name(obj_desc->mutex.node),
379                             (unsigned long)obj_desc->mutex.owner_thread->
380                             thread_id));
381                 return_ACPI_STATUS(AE_AML_NOT_OWNER);
382         }
383
384         /* Must have a valid thread ID */
385
386         if (!walk_state->thread) {
387                 ACPI_ERROR((AE_INFO,
388                             "Cannot release Mutex [%4.4s], null thread info",
389                             acpi_ut_get_node_name(obj_desc->mutex.node)));
390                 return_ACPI_STATUS(AE_AML_INTERNAL);
391         }
392
393         /*
394          * The sync level of the mutex must be less than or equal to the current
395          * sync level
396          */
397         if (obj_desc->mutex.sync_level > walk_state->thread->current_sync_level) {
398                 ACPI_ERROR((AE_INFO,
399                             "Cannot release Mutex [%4.4s], SyncLevel mismatch: mutex %d current %d",
400                             acpi_ut_get_node_name(obj_desc->mutex.node),
401                             obj_desc->mutex.sync_level,
402                             walk_state->thread->current_sync_level));
403                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
404         }
405
406         status = acpi_ex_release_mutex_object(obj_desc);
407
408         if (obj_desc->mutex.acquisition_depth == 0) {
409
410                 /* Restore the original sync_level */
411
412                 walk_state->thread->current_sync_level =
413                     obj_desc->mutex.original_sync_level;
414         }
415         return_ACPI_STATUS(status);
416 }
417
418 /*******************************************************************************
419  *
420  * FUNCTION:    acpi_ex_release_all_mutexes
421  *
422  * PARAMETERS:  Thread          - Current executing thread object
423  *
424  * RETURN:      Status
425  *
426  * DESCRIPTION: Release all mutexes held by this thread
427  *
428  * NOTE: This function is called as the thread is exiting the interpreter.
429  * Mutexes are not released when an individual control method is exited, but
430  * only when the parent thread actually exits the interpreter. This allows one
431  * method to acquire a mutex, and a different method to release it, as long as
432  * this is performed underneath a single parent control method.
433  *
434  ******************************************************************************/
435
436 void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
437 {
438         union acpi_operand_object *next = thread->acquired_mutex_list;
439         union acpi_operand_object *obj_desc;
440
441         ACPI_FUNCTION_ENTRY();
442
443         /* Traverse the list of owned mutexes, releasing each one */
444
445         while (next) {
446                 obj_desc = next;
447                 next = obj_desc->mutex.next;
448
449                 obj_desc->mutex.prev = NULL;
450                 obj_desc->mutex.next = NULL;
451                 obj_desc->mutex.acquisition_depth = 0;
452
453                 /* Release the mutex, special case for Global Lock */
454
455                 if (obj_desc == acpi_gbl_global_lock_mutex) {
456
457                         /* Ignore errors */
458
459                         (void)acpi_ev_release_global_lock();
460                 } else {
461                         acpi_os_release_mutex(obj_desc->mutex.os_mutex);
462                 }
463
464                 /* Mark mutex unowned */
465
466                 obj_desc->mutex.owner_thread = NULL;
467                 obj_desc->mutex.thread_id = NULL;
468
469                 /* Update Thread sync_level (Last mutex is the important one) */
470
471                 thread->current_sync_level =
472                     obj_desc->mutex.original_sync_level;
473         }
474 }