err.no 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 }
  89
  90 /*******************************************************************************
  91  *
  92  * FUNCTION:    acpi_ex_link_mutex
  93  *
  94  * PARAMETERS:  obj_desc        - The mutex to be linked
  95  *              Thread          - Current executing thread object
  96  *
  97  * RETURN:      None
  98  *
  99  * DESCRIPTION: Add a mutex to the "AcquiredMutex" list for this walk
 100  *
 101  ******************************************************************************/
 102
 103 static void
 104 acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
 105                    struct acpi_thread_state *thread)
 106 {
 107         union acpi_operand_object *list_head;
 108
 109         list_head = thread->acquired_mutex_list;
 110
 111         /* This object will be the first object in the list */
 112
 113         obj_desc->mutex.prev = NULL;
 114         obj_desc->mutex.next = list_head;
 115
 116         /* Update old first object to point back to this object */
 117
 118         if (list_head) {
 119                 list_head->mutex.prev = obj_desc;
 120         }
 121
 122         /* Update list head */
 123
 124         thread->acquired_mutex_list = obj_desc;
 125 }
 126
 127 /*******************************************************************************
 128  *
 129  * FUNCTION:    acpi_ex_acquire_mutex
 130  *
 131  * PARAMETERS:  time_desc           - Timeout integer
 132  *              obj_desc            - Mutex object
 133  *              walk_state          - Current method execution state
 134  *
 135  * RETURN:      Status
 136  *
 137  * DESCRIPTION: Acquire an AML mutex
 138  *
 139  ******************************************************************************/
 140
 141 acpi_status
 142 acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
 143                       union acpi_operand_object *obj_desc,
 144                       struct acpi_walk_state *walk_state)
 145 {
 146         acpi_status status;
 147
 148         ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc);
 149
 150         if (!obj_desc) {
 151                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 152         }
 153
 154         /* Sanity check: we must have a valid thread ID */
 155
 156         if (!walk_state->thread) {
 157                 ACPI_ERROR((AE_INFO,
 158                             "Cannot acquire Mutex [%4.4s], null thread info",
 159                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 160                 return_ACPI_STATUS(AE_AML_INTERNAL);
 161         }
 162
 163         /*
 164          * Current Sync must be less than or equal to the sync level of the
 165          * mutex. This mechanism provides some deadlock prevention
 166          */
 167         if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
 168                 ACPI_ERROR((AE_INFO,
 169                             "Cannot acquire Mutex [%4.4s], current SyncLevel is too large (%d)",
 170                             acpi_ut_get_node_name(obj_desc->mutex.node),
 171                             walk_state->thread->current_sync_level));
 172                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 173         }
 174
 175         /* Support for multiple acquires by the owning thread */
 176
 177         if (obj_desc->mutex.owner_thread) {
 178                 if (obj_desc->mutex.owner_thread->thread_id ==
 179                     walk_state->thread->thread_id) {
 180                         /*
 181                          * The mutex is already owned by this thread, just increment the
 182                          * acquisition depth
 183                          */
 184                         obj_desc->mutex.acquisition_depth++;
 185                         return_ACPI_STATUS(AE_OK);
 186                 }
 187         }
 188
 189         /* Acquire the mutex, wait if necessary. Special case for Global Lock */
 190
 191         if (obj_desc->mutex.os_mutex == acpi_gbl_global_lock_mutex) {
 192                 status =
 193                     acpi_ev_acquire_global_lock((u16) time_desc->integer.value);
 194         } else {
 195                 status = acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex,
 196                                                    (u16) time_desc->integer.
 197                                                    value);
 198         }
 199
 200         if (ACPI_FAILURE(status)) {
 201
 202                 /* Includes failure from a timeout on time_desc */
 203
 204                 return_ACPI_STATUS(status);
 205         }
 206
 207         /* Have the mutex: update mutex and walk info and save the sync_level */
 208
 209         obj_desc->mutex.owner_thread = walk_state->thread;
 210         obj_desc->mutex.acquisition_depth = 1;
 211         obj_desc->mutex.original_sync_level =
 212             walk_state->thread->current_sync_level;
 213
 214         walk_state->thread->current_sync_level = obj_desc->mutex.sync_level;
 215
 216         /* Link the mutex to the current thread for force-unlock at method exit */
 217
 218         acpi_ex_link_mutex(obj_desc, walk_state->thread);
 219         return_ACPI_STATUS(AE_OK);
 220 }
 221
 222 /*******************************************************************************
 223  *
 224  * FUNCTION:    acpi_ex_release_mutex
 225  *
 226  * PARAMETERS:  obj_desc            - The object descriptor for this op
 227  *              walk_state          - Current method execution state
 228  *
 229  * RETURN:      Status
 230  *
 231  * DESCRIPTION: Release a previously acquired Mutex.
 232  *
 233  ******************************************************************************/
 234
 235 acpi_status
 236 acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
 237                       struct acpi_walk_state *walk_state)
 238 {
 239         acpi_status status = AE_OK;
 240
 241         ACPI_FUNCTION_TRACE(ex_release_mutex);
 242
 243         if (!obj_desc) {
 244                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 245         }
 246
 247         /* The mutex must have been previously acquired in order to release it */
 248
 249         if (!obj_desc->mutex.owner_thread) {
 250                 ACPI_ERROR((AE_INFO,
 251                             "Cannot release Mutex [%4.4s], not acquired",
 252                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 253                 return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
 254         }
 255
 256         /* Sanity check: we must have a valid thread ID */
 257
 258         if (!walk_state->thread) {
 259                 ACPI_ERROR((AE_INFO,
 260                             "Cannot release Mutex [%4.4s], null thread info",
 261                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 262                 return_ACPI_STATUS(AE_AML_INTERNAL);
 263         }
 264
 265         /*
 266          * The Mutex is owned, but this thread must be the owner.
 267          * Special case for Global Lock, any thread can release
 268          */
 269         if ((obj_desc->mutex.owner_thread->thread_id !=
 270              walk_state->thread->thread_id)
 271             && (obj_desc->mutex.os_mutex != acpi_gbl_global_lock_mutex)) {
 272                 ACPI_ERROR((AE_INFO,
 273                             "Thread %lX cannot release Mutex [%4.4s] acquired by thread %lX",
 274                             (unsigned long)walk_state->thread->thread_id,
 275                             acpi_ut_get_node_name(obj_desc->mutex.node),
 276                             (unsigned long)obj_desc->mutex.owner_thread->
 277                             thread_id));
 278                 return_ACPI_STATUS(AE_AML_NOT_OWNER);
 279         }
 280
 281         /*
 282          * The sync level of the mutex must be less than or equal to the current
 283          * sync level
 284          */
 285         if (obj_desc->mutex.sync_level > walk_state->thread->current_sync_level) {
 286                 ACPI_ERROR((AE_INFO,
 287                             "Cannot release Mutex [%4.4s], incorrect SyncLevel",
 288                             acpi_ut_get_node_name(obj_desc->mutex.node)));
 289                 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
 290         }
 291
 292         /* Match multiple Acquires with multiple Releases */
 293
 294         obj_desc->mutex.acquisition_depth--;
 295         if (obj_desc->mutex.acquisition_depth != 0) {
 296
 297                 /* Just decrement the depth and return */
 298
 299                 return_ACPI_STATUS(AE_OK);
 300         }
 301
 302         /* Unlink the mutex from the owner's list */
 303
 304         acpi_ex_unlink_mutex(obj_desc);
 305
 306         /* Release the mutex, special case for Global Lock */
 307
 308         if (obj_desc->mutex.os_mutex == acpi_gbl_global_lock_mutex) {
 309                 status = acpi_ev_release_global_lock();
 310         } else {
 311                 acpi_os_release_mutex(obj_desc->mutex.os_mutex);
 312         }
 313
 314         /* Update the mutex and restore sync_level */
 315
 316         obj_desc->mutex.owner_thread = NULL;
 317         walk_state->thread->current_sync_level =
 318             obj_desc->mutex.original_sync_level;
 319
 320         return_ACPI_STATUS(status);
 321 }
 322
 323 /*******************************************************************************
 324  *
 325  * FUNCTION:    acpi_ex_release_all_mutexes
 326  *
 327  * PARAMETERS:  Thread          - Current executing thread object
 328  *
 329  * RETURN:      Status
 330  *
 331  * DESCRIPTION: Release all mutexes held by this thread
 332  *
 333  * NOTE: This function is called as the thread is exiting the interpreter.
 334  * Mutexes are not released when an individual control method is exited, but
 335  * only when the parent thread actually exits the interpreter. This allows one
 336  * method to acquire a mutex, and a different method to release it, as long as
 337  * this is performed underneath a single parent control method.
 338  *
 339  ******************************************************************************/
 340
 341 void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
 342 {
 343         union acpi_operand_object *next = thread->acquired_mutex_list;
 344         union acpi_operand_object *obj_desc;
 345
 346         ACPI_FUNCTION_ENTRY();
 347
 348         /* Traverse the list of owned mutexes, releasing each one */
 349
 350         while (next) {
 351                 obj_desc = next;
 352                 next = obj_desc->mutex.next;
 353
 354                 obj_desc->mutex.prev = NULL;
 355                 obj_desc->mutex.next = NULL;
 356                 obj_desc->mutex.acquisition_depth = 0;
 357
 358                 /* Release the mutex, special case for Global Lock */
 359
 360                 if (obj_desc->mutex.os_mutex == acpi_gbl_global_lock_mutex) {
 361
 362                         /* Ignore errors */
 363
 364                         (void)acpi_ev_release_global_lock();
 365                 } else {
 366                         acpi_os_release_mutex(obj_desc->mutex.os_mutex);
 367                 }
 368
 369                 /* Mark mutex unowned */
 370
 371                 obj_desc->mutex.owner_thread = NULL;
 372
 373                 /* Update Thread sync_level (Last mutex is the important one) */
 374
 375                 thread->current_sync_level =
 376                     obj_desc->mutex.original_sync_level;
 377         }
 378 }