git.oblomov.eu Git - linux-2.6/blob - drivers/acpi/executer/exmutex.c

   1
   2 /******************************************************************************
   3  *
   4  * Module Name: exmutex - ASL Mutex Acquire/Release functions
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2007, R. Byron Moore
  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 <acpi/acinterp.h>
  47 #include <acpi/acevents.h>
  48
  49 #define _COMPONENT          ACPI_EXECUTER
  50 ACPI_MODULE_NAME("exmutex")
  51
  52 /* Local prototypes */
  53 static void
  54 acpi_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
  69 void 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         } else {
  86                 thread->acquired_mutex_list = obj_desc->mutex.next;
  87         }
  88         return;
  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         /* No obj_desc->Mutex.owner_thread for Global Lock */
 303
 304         /*
 305          * Mutex to be released must be at the head of acquired list to prevent
 306          * deadlock. (The head of the list is the last mutex acquired.)
 307          */
 308         if (obj_desc->mutex.owner_thread &&
 309             (obj_desc != obj_desc->mutex.owner_thread->acquired_mutex_list)) {
 310                 return (AE_AML_MUTEX_ORDER);
 311         }
 312
 313         /* Match multiple Acquires with multiple Releases */
 314
 315         obj_desc->mutex.acquisition_depth--;
 316         if (obj_desc->mutex.acquisition_depth != 0) {
 317
 318                 /* Just decrement the depth and return */
 319
 320                 return_ACPI_STATUS(AE_OK);
 321         }
 322
 323         if (obj_desc->mutex.owner_thread) {
 324
 325                 /* Unlink the mutex from the owner's list */
 326
 327                 acpi_ex_unlink_mutex(obj_desc);
 328                 obj_desc->mutex.owner_thread = NULL;
 329         }
 330
 331         /* Release the mutex, special case for Global Lock */
 332
 333         if (obj_desc == acpi_gbl_global_lock_mutex) {
 334                 status = acpi_ev_release_global_lock();
 335         } else {
 336                 acpi_os_release_mutex(obj_desc->mutex.os_mutex);
 337         }
 338
 339         /* Clear mutex info */
 340
 341         obj_desc->mutex.thread_id = 0;
 342         return_ACPI_STATUS(status);
 343 }
 344
 345 /*******************************************************************************
 346  *
 347  * FUNCTION:    acpi_ex_release_mutex
 348  *
 349  * PARAMETERS:  obj_desc            - The object descriptor for this op
 350  *              walk_state          - Current method execution state
 351  *
 352  * RETURN:      Status
 353  *
 354  * DESCRIPTION: Release a previously acquired Mutex.
 355  *
 356  ******************************************************************************/
 357
 358 acpi_status
 359 acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 360                       struct acpi_walk_state *walk_state)
 361 {
 362         acpi_status status = AE_OK;
 363
 364         ACPI_FUNCTION_TRACE(ex_release_mutex);
 365
 366         if (!obj_desc) {
 367                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 368         }
 369
 370         /* The mutex must have been previously acquired in order to release it */
 371
 372         if (!obj_desc->mutex.owner_thread) {
 373                 ACPI_ERROR((AE_INFO,
 374                             "Cannot release Mutex [%4.4s], not acquired",
 375                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 376                 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
 377         }
 378
 379         /*
 380          * The Mutex is owned, but this thread must be the owner.
 381          * Special case for Global Lock, any thread can release
 382          */
 383         if ((obj_desc->mutex.owner_thread->thread_id !=
 384              walk_state->thread->thread_id)
 385             && (obj_desc != acpi_gbl_global_lock_mutex)) {
 386                 ACPI_ERROR((AE_INFO,
 387                             "Thread %lX cannot release Mutex [%4.4s] acquired by thread %lX",
 388                             (unsigned long)walk_state->thread->thread_id,
 389                             acpi_ut_get_node_name(obj_desc->mutex.node),
 390                             (unsigned long)obj_desc->mutex.owner_thread->
 391                             thread_id));
 392                 return_ACPI_STATUS(AE_AML_NOT_OWNER);
 393         }
 394
 395         /* Must have a valid thread ID */
 396
 397         if (!walk_state->thread) {
 398                 ACPI_ERROR((AE_INFO,
 399                             "Cannot release Mutex [%4.4s], null thread info",
 400                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 401                 return_ACPI_STATUS(AE_AML_INTERNAL);
 402         }
 403
 404         /*
 405          * The sync level of the mutex must be less than or equal to the current
 406          * sync level
 407          */
 408         if (obj_desc->mutex.sync_level > walk_state->thread->current_sync_level) {
 409                 ACPI_ERROR((AE_INFO,
 410                             "Cannot release Mutex [%4.4s], SyncLevel mismatch: mutex %d current %d",
 411                             acpi_ut_get_node_name(obj_desc->mutex.node),
 412                             obj_desc->mutex.sync_level,
 413                             walk_state->thread->current_sync_level));
 414                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 415         }
 416
 417         status = acpi_ex_release_mutex_object(obj_desc);
 418         if (ACPI_FAILURE(status)) {
 419                 return_ACPI_STATUS(status);
 420         }
 421
 422         if (obj_desc->mutex.acquisition_depth == 0) {
 423
 424                 /* Restore the original sync_level */
 425
 426                 walk_state->thread->current_sync_level =
 427                     obj_desc->mutex.original_sync_level;
 428         }
 429
 430         return_ACPI_STATUS(status);
 431 }
 432
 433 /*******************************************************************************
 434  *
 435  * FUNCTION:    acpi_ex_release_all_mutexes
 436  *
 437  * PARAMETERS:  Thread          - Current executing thread object
 438  *
 439  * RETURN:      Status
 440  *
 441  * DESCRIPTION: Release all mutexes held by this thread
 442  *
 443  * NOTE: This function is called as the thread is exiting the interpreter.
 444  * Mutexes are not released when an individual control method is exited, but
 445  * only when the parent thread actually exits the interpreter. This allows one
 446  * method to acquire a mutex, and a different method to release it, as long as
 447  * this is performed underneath a single parent control method.
 448  *
 449  ******************************************************************************/
 450
 451 void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
 452 {
 453         union acpi_operand_object *next = thread->acquired_mutex_list;
 454         union acpi_operand_object *obj_desc;
 455
 456         ACPI_FUNCTION_ENTRY();
 457
 458         /* Traverse the list of owned mutexes, releasing each one */
 459
 460         while (next) {
 461                 obj_desc = next;
 462                 next = obj_desc->mutex.next;
 463
 464                 obj_desc->mutex.prev = NULL;
 465                 obj_desc->mutex.next = NULL;
 466                 obj_desc->mutex.acquisition_depth = 0;
 467
 468                 /* Release the mutex, special case for Global Lock */
 469
 470                 if (obj_desc == acpi_gbl_global_lock_mutex) {
 471
 472                         /* Ignore errors */
 473
 474                         (void)acpi_ev_release_global_lock();
 475                 } else {
 476                         acpi_os_release_mutex(obj_desc->mutex.os_mutex);
 477                 }
 478
 479                 /* Mark mutex unowned */
 480
 481                 obj_desc->mutex.owner_thread = NULL;
 482                 obj_desc->mutex.thread_id = 0;
 483
 484                 /* Update Thread sync_level (Last mutex is the important one) */
 485
 486                 thread->current_sync_level =
 487                     obj_desc->mutex.original_sync_level;
 488         }
 489 }