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 - 2006, 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
  48 #define _COMPONENT          ACPI_EXECUTER
  49 ACPI_MODULE_NAME("exmutex")
  50
  51 /* Local prototypes */
  52 static void
  53 acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
  54                    struct acpi_thread_state *thread);
  55
  56 /*******************************************************************************
  57  *
  58  * FUNCTION:    acpi_ex_unlink_mutex
  59  *
  60  * PARAMETERS:  obj_desc            - The mutex to be unlinked
  61  *
  62  * RETURN:      None
  63  *
  64  * DESCRIPTION: Remove a mutex from the "acquired_mutex" list
  65  *
  66  ******************************************************************************/
  67
  68 void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
  69 {
  70         struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;
  71
  72         if (!thread) {
  73                 return;
  74         }
  75
  76         /* Doubly linked list */
  77
  78         if (obj_desc->mutex.next) {
  79                 (obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
  80         }
  81
  82         if (obj_desc->mutex.prev) {
  83                 (obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
  84         } else {
  85                 thread->acquired_mutex_list = obj_desc->mutex.next;
  86         }
  87 }
  88
  89 /*******************************************************************************
  90  *
  91  * FUNCTION:    acpi_ex_link_mutex
  92  *
  93  * PARAMETERS:  obj_desc        - The mutex to be linked
  94  *              Thread          - Current executing thread object
  95  *
  96  * RETURN:      None
  97  *
  98  * DESCRIPTION: Add a mutex to the "acquired_mutex" list for this walk
  99  *
 100  ******************************************************************************/
 101
 102 static void
 103 acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
 104                    struct acpi_thread_state *thread)
 105 {
 106         union acpi_operand_object *list_head;
 107
 108         list_head = thread->acquired_mutex_list;
 109
 110         /* This object will be the first object in the list */
 111
 112         obj_desc->mutex.prev = NULL;
 113         obj_desc->mutex.next = list_head;
 114
 115         /* Update old first object to point back to this object */
 116
 117         if (list_head) {
 118                 list_head->mutex.prev = obj_desc;
 119         }
 120
 121         /* Update list head */
 122
 123         thread->acquired_mutex_list = obj_desc;
 124 }
 125
 126 /*******************************************************************************
 127  *
 128  * FUNCTION:    acpi_ex_acquire_mutex
 129  *
 130  * PARAMETERS:  time_desc           - Timeout integer
 131  *              obj_desc            - Mutex object
 132  *              walk_state          - Current method execution state
 133  *
 134  * RETURN:      Status
 135  *
 136  * DESCRIPTION: Acquire an AML mutex
 137  *
 138  ******************************************************************************/
 139
 140 acpi_status
 141 acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
 142                       union acpi_operand_object *obj_desc,
 143                       struct acpi_walk_state *walk_state)
 144 {
 145         acpi_status status;
 146
 147         ACPI_FUNCTION_TRACE_PTR("ex_acquire_mutex", obj_desc);
 148
 149         if (!obj_desc) {
 150                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 151         }
 152
 153         /* Sanity check -- we must have a valid thread ID */
 154
 155         if (!walk_state->thread) {
 156                 ACPI_ERROR((AE_INFO,
 157                             "Cannot acquire Mutex [%4.4s], null thread info",
 158                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 159                 return_ACPI_STATUS(AE_AML_INTERNAL);
 160         }
 161
 162         /*
 163          * Current Sync must be less than or equal to the sync level of the
 164          * mutex.  This mechanism provides some deadlock prevention
 165          */
 166         if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
 167                 ACPI_ERROR((AE_INFO,
 168                             "Cannot acquire Mutex [%4.4s], incorrect sync_level",
 169                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 170                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 171         }
 172
 173         /* Support for multiple acquires by the owning thread */
 174
 175         if (obj_desc->mutex.owner_thread) {
 176                 /* Special case for Global Lock, allow all threads */
 177
 178                 if ((obj_desc->mutex.owner_thread->thread_id ==
 179                      walk_state->thread->thread_id) ||
 180                     (obj_desc->mutex.semaphore ==
 181                      acpi_gbl_global_lock_semaphore)) {
 182                         /*
 183                          * The mutex is already owned by this thread,
 184                          * just increment the acquisition depth
 185                          */
 186                         obj_desc->mutex.acquisition_depth++;
 187                         return_ACPI_STATUS(AE_OK);
 188                 }
 189         }
 190
 191         /* Acquire the mutex, wait if necessary */
 192
 193         status = acpi_ex_system_acquire_mutex(time_desc, obj_desc);
 194         if (ACPI_FAILURE(status)) {
 195                 /* Includes failure from a timeout on time_desc */
 196
 197                 return_ACPI_STATUS(status);
 198         }
 199
 200         /* Have the mutex: update mutex and walk info and save the sync_level */
 201
 202         obj_desc->mutex.owner_thread = walk_state->thread;
 203         obj_desc->mutex.acquisition_depth = 1;
 204         obj_desc->mutex.original_sync_level =
 205             walk_state->thread->current_sync_level;
 206
 207         walk_state->thread->current_sync_level = obj_desc->mutex.sync_level;
 208
 209         /* Link the mutex to the current thread for force-unlock at method exit */
 210
 211         acpi_ex_link_mutex(obj_desc, walk_state->thread);
 212
 213         return_ACPI_STATUS(AE_OK);
 214 }
 215
 216 /*******************************************************************************
 217  *
 218  * FUNCTION:    acpi_ex_release_mutex
 219  *
 220  * PARAMETERS:  obj_desc            - The object descriptor for this op
 221  *              walk_state          - Current method execution state
 222  *
 223  * RETURN:      Status
 224  *
 225  * DESCRIPTION: Release a previously acquired Mutex.
 226  *
 227  ******************************************************************************/
 228
 229 acpi_status
 230 acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 231                       struct acpi_walk_state *walk_state)
 232 {
 233         acpi_status status;
 234
 235         ACPI_FUNCTION_TRACE("ex_release_mutex");
 236
 237         if (!obj_desc) {
 238                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 239         }
 240
 241         /* The mutex must have been previously acquired in order to release it */
 242
 243         if (!obj_desc->mutex.owner_thread) {
 244                 ACPI_ERROR((AE_INFO,
 245                             "Cannot release Mutex [%4.4s], not acquired",
 246                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 247                 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
 248         }
 249
 250         /* Sanity check -- we must have a valid thread ID */
 251
 252         if (!walk_state->thread) {
 253                 ACPI_ERROR((AE_INFO,
 254                             "Cannot release Mutex [%4.4s], null thread info",
 255                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 256                 return_ACPI_STATUS(AE_AML_INTERNAL);
 257         }
 258
 259         /*
 260          * The Mutex is owned, but this thread must be the owner.
 261          * Special case for Global Lock, any thread can release
 262          */
 263         if ((obj_desc->mutex.owner_thread->thread_id !=
 264              walk_state->thread->thread_id)
 265             && (obj_desc->mutex.semaphore != acpi_gbl_global_lock_semaphore)) {
 266                 ACPI_ERROR((AE_INFO,
 267                             "Thread %X cannot release Mutex [%4.4s] acquired by thread %X",
 268                             walk_state->thread->thread_id,
 269                             acpi_ut_get_node_name(obj_desc->mutex.node),
 270                             obj_desc->mutex.owner_thread->thread_id));
 271                 return_ACPI_STATUS(AE_AML_NOT_OWNER);
 272         }
 273
 274         /*
 275          * The sync level of the mutex must be less than or
 276          * equal to the current sync level
 277          */
 278         if (obj_desc->mutex.sync_level > walk_state->thread->current_sync_level) {
 279                 ACPI_ERROR((AE_INFO,
 280                             "Cannot release Mutex [%4.4s], incorrect sync_level",
 281                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 282                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 283         }
 284
 285         /* Match multiple Acquires with multiple Releases */
 286
 287         obj_desc->mutex.acquisition_depth--;
 288         if (obj_desc->mutex.acquisition_depth != 0) {
 289                 /* Just decrement the depth and return */
 290
 291                 return_ACPI_STATUS(AE_OK);
 292         }
 293
 294         /* Unlink the mutex from the owner's list */
 295
 296         acpi_ex_unlink_mutex(obj_desc);
 297
 298         /* Release the mutex */
 299
 300         status = acpi_ex_system_release_mutex(obj_desc);
 301
 302         /* Update the mutex and walk state, restore sync_level before acquire */
 303
 304         obj_desc->mutex.owner_thread = NULL;
 305         walk_state->thread->current_sync_level =
 306             obj_desc->mutex.original_sync_level;
 307
 308         return_ACPI_STATUS(status);
 309 }
 310
 311 /*******************************************************************************
 312  *
 313  * FUNCTION:    acpi_ex_release_all_mutexes
 314  *
 315  * PARAMETERS:  Thread          - Current executing thread object
 316  *
 317  * RETURN:      Status
 318  *
 319  * DESCRIPTION: Release all mutexes held by this thread
 320  *
 321  ******************************************************************************/
 322
 323 void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
 324 {
 325         union acpi_operand_object *next = thread->acquired_mutex_list;
 326         union acpi_operand_object *this;
 327         acpi_status status;
 328
 329         ACPI_FUNCTION_ENTRY();
 330
 331         /* Traverse the list of owned mutexes, releasing each one */
 332
 333         while (next) {
 334                 this = next;
 335                 next = this->mutex.next;
 336
 337                 this->mutex.acquisition_depth = 1;
 338                 this->mutex.prev = NULL;
 339                 this->mutex.next = NULL;
 340
 341                 /* Release the mutex */
 342
 343                 status = acpi_ex_system_release_mutex(this);
 344                 if (ACPI_FAILURE(status)) {
 345                         continue;
 346                 }
 347
 348                 /* Mark mutex unowned */
 349
 350                 this->mutex.owner_thread = NULL;
 351
 352                 /* Update Thread sync_level (Last mutex is the important one) */
 353
 354                 thread->current_sync_level = this->mutex.original_sync_level;
 355         }
 356 }