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utmutex.c

/*******************************************************************************
 *
 * Module Name: utmutex - local mutex support
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2007, R. Byron Moore
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>

#define _COMPONENT          ACPI_UTILITIES
ACPI_MODULE_NAME("utmutex")

/* Local prototypes */
static acpi_status acpi_ut_create_mutex(acpi_mutex_handle mutex_id);

static acpi_status acpi_ut_delete_mutex(acpi_mutex_handle mutex_id);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_mutex_initialize
 *
 * PARAMETERS:  None.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create the system mutex objects.
 *
 ******************************************************************************/

acpi_status acpi_ut_mutex_initialize(void)
{
      u32 i;
      acpi_status status;

      ACPI_FUNCTION_TRACE(ut_mutex_initialize);

      /*
       * Create each of the predefined mutex objects
       */
      for (i = 0; i < ACPI_NUM_MUTEX; i++) {
            status = acpi_ut_create_mutex(i);
            if (ACPI_FAILURE(status)) {
                  return_ACPI_STATUS(status);
            }
      }

      /* Create the spinlocks for use at interrupt level */

      spin_lock_init(acpi_gbl_gpe_lock);
      spin_lock_init(acpi_gbl_hardware_lock);

      return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_mutex_terminate
 *
 * PARAMETERS:  None.
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Delete all of the system mutex objects.
 *
 ******************************************************************************/

void acpi_ut_mutex_terminate(void)
{
      u32 i;

      ACPI_FUNCTION_TRACE(ut_mutex_terminate);

      /*
       * Delete each predefined mutex object
       */
      for (i = 0; i < ACPI_NUM_MUTEX; i++) {
            (void)acpi_ut_delete_mutex(i);
      }

      /* Delete the spinlocks */

      acpi_os_delete_lock(acpi_gbl_gpe_lock);
      acpi_os_delete_lock(acpi_gbl_hardware_lock);
      return_VOID;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_create_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be created
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a mutex object.
 *
 ******************************************************************************/

static acpi_status acpi_ut_create_mutex(acpi_mutex_handle mutex_id)
{
      acpi_status status = AE_OK;

      ACPI_FUNCTION_TRACE_U32(ut_create_mutex, mutex_id);

      if (mutex_id > ACPI_MAX_MUTEX) {
            return_ACPI_STATUS(AE_BAD_PARAMETER);
      }

      if (!acpi_gbl_mutex_info[mutex_id].mutex) {
            status =
                acpi_os_create_mutex(&acpi_gbl_mutex_info[mutex_id].mutex);
            acpi_gbl_mutex_info[mutex_id].thread_id =
                ACPI_MUTEX_NOT_ACQUIRED;
            acpi_gbl_mutex_info[mutex_id].use_count = 0;
      }

      return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_delete_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be deleted
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Delete a mutex object.
 *
 ******************************************************************************/

static acpi_status acpi_ut_delete_mutex(acpi_mutex_handle mutex_id)
{

      ACPI_FUNCTION_TRACE_U32(ut_delete_mutex, mutex_id);

      if (mutex_id > ACPI_MAX_MUTEX) {
            return_ACPI_STATUS(AE_BAD_PARAMETER);
      }

      acpi_os_delete_mutex(acpi_gbl_mutex_info[mutex_id].mutex);

      acpi_gbl_mutex_info[mutex_id].mutex = NULL;
      acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;

      return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_acquire_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be acquired
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Acquire a mutex object.
 *
 ******************************************************************************/

acpi_status acpi_ut_acquire_mutex(acpi_mutex_handle mutex_id)
{
      acpi_status status;
      acpi_thread_id this_thread_id;

      ACPI_FUNCTION_NAME(ut_acquire_mutex);

      if (mutex_id > ACPI_MAX_MUTEX) {
            return (AE_BAD_PARAMETER);
      }

      this_thread_id = acpi_os_get_thread_id();

#ifdef ACPI_MUTEX_DEBUG
      {
            u32 i;
            /*
             * Mutex debug code, for internal debugging only.
             *
             * Deadlock prevention.  Check if this thread owns any mutexes of value
             * greater than or equal to this one.  If so, the thread has violated
             * the mutex ordering rule.  This indicates a coding error somewhere in
             * the ACPI subsystem code.
             */
            for (i = mutex_id; i < ACPI_MAX_MUTEX; i++) {
                  if (acpi_gbl_mutex_info[i].thread_id == this_thread_id) {
                        if (i == mutex_id) {
                              ACPI_ERROR((AE_INFO,
                                        "Mutex [%s] already acquired by this thread [%X]",
                                        acpi_ut_get_mutex_name
                                        (mutex_id),
                                        this_thread_id));

                              return (AE_ALREADY_ACQUIRED);
                        }

                        ACPI_ERROR((AE_INFO,
                                  "Invalid acquire order: Thread %X owns [%s], wants [%s]",
                                  this_thread_id,
                                  acpi_ut_get_mutex_name(i),
                                  acpi_ut_get_mutex_name(mutex_id)));

                        return (AE_ACQUIRE_DEADLOCK);
                  }
            }
      }
#endif

      ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
                    "Thread %lX attempting to acquire Mutex [%s]\n",
                    (unsigned long)this_thread_id,
                    acpi_ut_get_mutex_name(mutex_id)));

      status = acpi_os_acquire_mutex(acpi_gbl_mutex_info[mutex_id].mutex,
                               ACPI_WAIT_FOREVER);
      if (ACPI_SUCCESS(status)) {
            ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
                          "Thread %lX acquired Mutex [%s]\n",
                          (unsigned long)this_thread_id,
                          acpi_ut_get_mutex_name(mutex_id)));

            acpi_gbl_mutex_info[mutex_id].use_count++;
            acpi_gbl_mutex_info[mutex_id].thread_id = this_thread_id;
      } else {
            ACPI_EXCEPTION((AE_INFO, status,
                        "Thread %lX could not acquire Mutex [%X]",
                        (unsigned long)this_thread_id, mutex_id));
      }

      return (status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_release_mutex
 *
 * PARAMETERS:  mutex_iD        - ID of the mutex to be released
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Release a mutex object.
 *
 ******************************************************************************/

acpi_status acpi_ut_release_mutex(acpi_mutex_handle mutex_id)
{
      acpi_thread_id this_thread_id;

      ACPI_FUNCTION_NAME(ut_release_mutex);

      this_thread_id = acpi_os_get_thread_id();
      ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
                    "Thread %lX releasing Mutex [%s]\n",
                    (unsigned long)this_thread_id,
                    acpi_ut_get_mutex_name(mutex_id)));

      if (mutex_id > ACPI_MAX_MUTEX) {
            return (AE_BAD_PARAMETER);
      }

      /*
       * Mutex must be acquired in order to release it!
       */
      if (acpi_gbl_mutex_info[mutex_id].thread_id == ACPI_MUTEX_NOT_ACQUIRED) {
            ACPI_ERROR((AE_INFO,
                      "Mutex [%X] is not acquired, cannot release",
                      mutex_id));

            return (AE_NOT_ACQUIRED);
      }
#ifdef ACPI_MUTEX_DEBUG
      {
            u32 i;
            /*
             * Mutex debug code, for internal debugging only.
             *
             * Deadlock prevention.  Check if this thread owns any mutexes of value
             * greater than this one.  If so, the thread has violated the mutex
             * ordering rule.  This indicates a coding error somewhere in
             * the ACPI subsystem code.
             */
            for (i = mutex_id; i < ACPI_MAX_MUTEX; i++) {
                  if (acpi_gbl_mutex_info[i].thread_id == this_thread_id) {
                        if (i == mutex_id) {
                              continue;
                        }

                        ACPI_ERROR((AE_INFO,
                                  "Invalid release order: owns [%s], releasing [%s]",
                                  acpi_ut_get_mutex_name(i),
                                  acpi_ut_get_mutex_name(mutex_id)));

                        return (AE_RELEASE_DEADLOCK);
                  }
            }
      }
#endif

      /* Mark unlocked FIRST */

      acpi_gbl_mutex_info[mutex_id].thread_id = ACPI_MUTEX_NOT_ACQUIRED;

      acpi_os_release_mutex(acpi_gbl_mutex_info[mutex_id].mutex);
      return (AE_OK);
}

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