git.oblomov.eu Git - linux-2.6/blob - drivers/acpi/utilities/utmutex.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: utmutex - local mutex support
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2006, R. Byron Moore
   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
  46 #define _COMPONENT          ACPI_UTILITIES
  47 ACPI_MODULE_NAME("utmutex")
  48
  49 /* Local prototypes */
  50 static acpi_status acpi_ut_create_mutex(acpi_mutex_handle mutex_id);
  51
  52 static acpi_status acpi_ut_delete_mutex(acpi_mutex_handle mutex_id);
  53
  54 /*******************************************************************************
  55  *
  56  * FUNCTION:    acpi_ut_mutex_initialize
  57  *
  58  * PARAMETERS:  None.
  59  *
  60  * RETURN:      Status
  61  *
  62  * DESCRIPTION: Create the system mutex objects.
  63  *
  64  ******************************************************************************/
  65
  66 acpi_status acpi_ut_mutex_initialize(void)
  67 {
  68         u32 i;
  69         acpi_status status;
  70
  71         ACPI_FUNCTION_TRACE("ut_mutex_initialize");
  72
  73         /*
  74          * Create each of the predefined mutex objects
  75          */
  76         for (i = 0; i < NUM_MUTEX; i++) {
  77                 status = acpi_ut_create_mutex(i);
  78                 if (ACPI_FAILURE(status)) {
  79                         return_ACPI_STATUS(status);
  80                 }
  81         }
  82
  83         status = acpi_os_create_lock(&acpi_gbl_gpe_lock);
  84         return_ACPI_STATUS(status);
  85 }
  86
  87 /*******************************************************************************
  88  *
  89  * FUNCTION:    acpi_ut_mutex_terminate
  90  *
  91  * PARAMETERS:  None.
  92  *
  93  * RETURN:      None.
  94  *
  95  * DESCRIPTION: Delete all of the system mutex objects.
  96  *
  97  ******************************************************************************/
  98
  99 void acpi_ut_mutex_terminate(void)
 100 {
 101         u32 i;
 102
 103         ACPI_FUNCTION_TRACE("ut_mutex_terminate");
 104
 105         /*
 106          * Delete each predefined mutex object
 107          */
 108         for (i = 0; i < NUM_MUTEX; i++) {
 109                 (void)acpi_ut_delete_mutex(i);
 110         }
 111
 112         acpi_os_delete_lock(acpi_gbl_gpe_lock);
 113         return_VOID;
 114 }
 115
 116 /*******************************************************************************
 117  *
 118  * FUNCTION:    acpi_ut_create_mutex
 119  *
 120  * PARAMETERS:  mutex_iD        - ID of the mutex to be created
 121  *
 122  * RETURN:      Status
 123  *
 124  * DESCRIPTION: Create a mutex object.
 125  *
 126  ******************************************************************************/
 127
 128 static acpi_status acpi_ut_create_mutex(acpi_mutex_handle mutex_id)
 129 {
 130         acpi_status status = AE_OK;
 131
 132         ACPI_FUNCTION_TRACE_U32("ut_create_mutex", mutex_id);
 133
 134         if (mutex_id > MAX_MUTEX) {
 135                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 136         }
 137
 138         if (!acpi_gbl_mutex_info[mutex_id].mutex) {
 139                 status = acpi_os_create_semaphore(1, 1,
 140                                                   &acpi_gbl_mutex_info
 141                                                   [mutex_id].mutex);
 142                 acpi_gbl_mutex_info[mutex_id].thread_id =
 143                     ACPI_MUTEX_NOT_ACQUIRED;
 144                 acpi_gbl_mutex_info[mutex_id].use_count = 0;
 145         }
 146
 147         return_ACPI_STATUS(status);
 148 }
 149
 150 /*******************************************************************************
 151  *
 152  * FUNCTION:    acpi_ut_delete_mutex
 153  *
 154  * PARAMETERS:  mutex_iD        - ID of the mutex to be deleted
 155  *
 156  * RETURN:      Status
 157  *
 158  * DESCRIPTION: Delete a mutex object.
 159  *
 160  ******************************************************************************/
 161
 162 static acpi_status acpi_ut_delete_mutex(acpi_mutex_handle mutex_id)
 163 {
 164         acpi_status status;
 165
 166         ACPI_FUNCTION_TRACE_U32("ut_delete_mutex", mutex_id);
 167
 168         if (mutex_id > MAX_MUTEX) {
 169                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 170         }
 171
 172         status = acpi_os_delete_semaphore(acpi_gbl_mutex_info[mutex_id].mutex);
 173
 174         acpi_gbl_mutex_info[mutex_id].mutex = NULL;
 175         acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;
 176
 177         return_ACPI_STATUS(status);
 178 }
 179
 180 /*******************************************************************************
 181  *
 182  * FUNCTION:    acpi_ut_acquire_mutex
 183  *
 184  * PARAMETERS:  mutex_iD        - ID of the mutex to be acquired
 185  *
 186  * RETURN:      Status
 187  *
 188  * DESCRIPTION: Acquire a mutex object.
 189  *
 190  ******************************************************************************/
 191
 192 acpi_status acpi_ut_acquire_mutex(acpi_mutex_handle mutex_id)
 193 {
 194         acpi_status status;
 195         u32 this_thread_id;
 196
 197         ACPI_FUNCTION_NAME("ut_acquire_mutex");
 198
 199         if (mutex_id > MAX_MUTEX) {
 200                 return (AE_BAD_PARAMETER);
 201         }
 202
 203         this_thread_id = acpi_os_get_thread_id();
 204
 205 #ifdef ACPI_MUTEX_DEBUG
 206         {
 207                 u32 i;
 208                 /*
 209                  * Mutex debug code, for internal debugging only.
 210                  *
 211                  * Deadlock prevention.  Check if this thread owns any mutexes of value
 212                  * greater than or equal to this one.  If so, the thread has violated
 213                  * the mutex ordering rule.  This indicates a coding error somewhere in
 214                  * the ACPI subsystem code.
 215                  */
 216                 for (i = mutex_id; i < MAX_MUTEX; i++) {
 217                         if (acpi_gbl_mutex_info[i].thread_id == this_thread_id) {
 218                                 if (i == mutex_id) {
 219                                         ACPI_ERROR((AE_INFO,
 220                                                     "Mutex [%s] already acquired by this thread [%X]",
 221                                                     acpi_ut_get_mutex_name
 222                                                     (mutex_id),
 223                                                     this_thread_id));
 224
 225                                         return (AE_ALREADY_ACQUIRED);
 226                                 }
 227
 228                                 ACPI_ERROR((AE_INFO,
 229                                             "Invalid acquire order: Thread %X owns [%s], wants [%s]",
 230                                             this_thread_id,
 231                                             acpi_ut_get_mutex_name(i),
 232                                             acpi_ut_get_mutex_name(mutex_id)));
 233
 234                                 return (AE_ACQUIRE_DEADLOCK);
 235                         }
 236                 }
 237         }
 238 #endif
 239
 240         ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
 241                           "Thread %X attempting to acquire Mutex [%s]\n",
 242                           this_thread_id, acpi_ut_get_mutex_name(mutex_id)));
 243
 244         status = acpi_os_wait_semaphore(acpi_gbl_mutex_info[mutex_id].mutex,
 245                                         1, ACPI_WAIT_FOREVER);
 246         if (ACPI_SUCCESS(status)) {
 247                 ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
 248                                   "Thread %X acquired Mutex [%s]\n",
 249                                   this_thread_id,
 250                                   acpi_ut_get_mutex_name(mutex_id)));
 251
 252                 acpi_gbl_mutex_info[mutex_id].use_count++;
 253                 acpi_gbl_mutex_info[mutex_id].thread_id = this_thread_id;
 254         } else {
 255                 ACPI_EXCEPTION((AE_INFO, status,
 256                                 "Thread %X could not acquire Mutex [%X]",
 257                                 this_thread_id, mutex_id));
 258         }
 259
 260         return (status);
 261 }
 262
 263 /*******************************************************************************
 264  *
 265  * FUNCTION:    acpi_ut_release_mutex
 266  *
 267  * PARAMETERS:  mutex_iD        - ID of the mutex to be released
 268  *
 269  * RETURN:      Status
 270  *
 271  * DESCRIPTION: Release a mutex object.
 272  *
 273  ******************************************************************************/
 274
 275 acpi_status acpi_ut_release_mutex(acpi_mutex_handle mutex_id)
 276 {
 277         acpi_status status;
 278         u32 this_thread_id;
 279
 280         ACPI_FUNCTION_NAME("ut_release_mutex");
 281
 282         this_thread_id = acpi_os_get_thread_id();
 283         ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
 284                           "Thread %X releasing Mutex [%s]\n", this_thread_id,
 285                           acpi_ut_get_mutex_name(mutex_id)));
 286
 287         if (mutex_id > MAX_MUTEX) {
 288                 return (AE_BAD_PARAMETER);
 289         }
 290
 291         /*
 292          * Mutex must be acquired in order to release it!
 293          */
 294         if (acpi_gbl_mutex_info[mutex_id].thread_id == ACPI_MUTEX_NOT_ACQUIRED) {
 295                 ACPI_ERROR((AE_INFO,
 296                             "Mutex [%X] is not acquired, cannot release",
 297                             mutex_id));
 298
 299                 return (AE_NOT_ACQUIRED);
 300         }
 301 #ifdef ACPI_MUTEX_DEBUG
 302         {
 303                 u32 i;
 304                 /*
 305                  * Mutex debug code, for internal debugging only.
 306                  *
 307                  * Deadlock prevention.  Check if this thread owns any mutexes of value
 308                  * greater than this one.  If so, the thread has violated the mutex
 309                  * ordering rule.  This indicates a coding error somewhere in
 310                  * the ACPI subsystem code.
 311                  */
 312                 for (i = mutex_id; i < MAX_MUTEX; i++) {
 313                         if (acpi_gbl_mutex_info[i].thread_id == this_thread_id) {
 314                                 if (i == mutex_id) {
 315                                         continue;
 316                                 }
 317
 318                                 ACPI_ERROR((AE_INFO,
 319                                             "Invalid release order: owns [%s], releasing [%s]",
 320                                             acpi_ut_get_mutex_name(i),
 321                                             acpi_ut_get_mutex_name(mutex_id)));
 322
 323                                 return (AE_RELEASE_DEADLOCK);
 324                         }
 325                 }
 326         }
 327 #endif
 328
 329         /* Mark unlocked FIRST */
 330
 331         acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;
 332
 333         status =
 334             acpi_os_signal_semaphore(acpi_gbl_mutex_info[mutex_id].mutex, 1);
 335
 336         if (ACPI_FAILURE(status)) {
 337                 ACPI_EXCEPTION((AE_INFO, status,
 338                                 "Thread %X could not release Mutex [%X]",
 339                                 this_thread_id, mutex_id));
 340         } else {
 341                 ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
 342                                   "Thread %X released Mutex [%s]\n",
 343                                   this_thread_id,
 344                                   acpi_ut_get_mutex_name(mutex_id)));
 345         }
 346
 347         return (status);
 348 }