drivers/acpi/acpica/exmutex.c

   1 /******************************************************************************
   2  *
   3  * Module Name: exmutex - ASL Mutex Acquire/Release functions
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, 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
  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
  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
 112 static void
 113 acpi_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
 159 acpi_status
 160 acpi_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
 223 acpi_status
 224 acpi_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
 300 acpi_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
 355 acpi_status
 356 acpi_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
 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_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 }