release/src-rt-6.x.4708/linux/linux-2.6.36/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
  89                  * the previous mutex on the list so that it may be preserved.
  90                  * This handles the case where several mutexes have been acquired
  91                  * at the same level, 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:  Timeout             - Timeout in milliseconds
 142  *              obj_desc            - Mutex object
 143  *              thread_id           - 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 state struct */
 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 (%u)",
 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         struct acpi_thread_state *owner_thread;
 363
 364         ACPI_FUNCTION_TRACE(ex_release_mutex);
 365
 366         if (!obj_desc) {
 367                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 368         }
 369
 370         owner_thread = obj_desc->mutex.owner_thread;
 371
 372         /* The mutex must have been previously acquired in order to release it */
 373
 374         if (!owner_thread) {
 375                 ACPI_ERROR((AE_INFO,
 376                             "Cannot release Mutex [%4.4s], not acquired",
 377                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 378                 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
 379         }
 380
 381         /* Must have a valid thread. */
 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 %p cannot release Mutex [%4.4s] acquired by thread %p",
 397                             ACPI_CAST_PTR(void, walk_state->thread->thread_id),
 398                             acpi_ut_get_node_name(obj_desc->mutex.node),
 399                             ACPI_CAST_PTR(void, 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
 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 }