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/******************************************************************************

 *

 * Module Name: exmutex - ASL Mutex Acquire/Release functions

 *

 *****************************************************************************/

/*

 * Copyright (C) 2000 - 2015, Intel Corp.

 * 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 

#include "accommon.h"

#include "acinterp.h"

#include "acevents.h"

#define _COMPONENT          ACPI_EXECUTER

ACPI_MODULE_NAME("exmutex")

/* Local prototypes */

static void

acpi_ex_link_mutex(union acpi_operand_object *obj_desc,

		   struct acpi_thread_state *thread);

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_unlink_mutex

 *

 * PARAMETERS:  obj_desc            - The mutex to be unlinked

 *

 * RETURN:      None

 *

 * DESCRIPTION: Remove a mutex from the "AcquiredMutex" list

 *

 ******************************************************************************/

void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)

{

	struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;

	if (!thread) {

		return;

	}

	/* Doubly linked list */

	if (obj_desc->mutex.next) {

		(obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;

	}

	if (obj_desc->mutex.prev) {

		(obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;

		/*

		 * Migrate the previous sync level associated with this mutex to

		 * the previous mutex on the list so that it may be preserved.

		 * This handles the case where several mutexes have been acquired

		 * at the same level, but are not released in opposite order.

		 */

		(obj_desc->mutex.prev)->mutex.original_sync_level =

		    obj_desc->mutex.original_sync_level;

	} else {

		thread->acquired_mutex_list = obj_desc->mutex.next;

	}

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_link_mutex

 *

 * PARAMETERS:  obj_desc            - The mutex to be linked

 *              thread              - Current executing thread object

 *

 * RETURN:      None

 *

 * DESCRIPTION: Add a mutex to the "AcquiredMutex" list for this walk

 *

 ******************************************************************************/

static void

acpi_ex_link_mutex(union acpi_operand_object *obj_desc,

		   struct acpi_thread_state *thread)

{

	union acpi_operand_object *list_head;

	list_head = thread->acquired_mutex_list;

	/* This object will be the first object in the list */

	obj_desc->mutex.prev = NULL;

	obj_desc->mutex.next = list_head;

	/* Update old first object to point back to this object */

	if (list_head) {

		list_head->mutex.prev = obj_desc;

	}

	/* Update list head */

	thread->acquired_mutex_list = obj_desc;

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_acquire_mutex_object

 *

 * PARAMETERS:  timeout             - Timeout in milliseconds

 *              obj_desc            - Mutex object

 *              thread_id           - Current thread state

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Acquire an AML mutex, low-level interface. Provides a common

 *              path that supports multiple acquires by the same thread.

 *

 * MUTEX:       Interpreter must be locked

 *

 * NOTE: This interface is called from three places:

 * 1) From acpi_ex_acquire_mutex, via an AML Acquire() operator

 * 2) From acpi_ex_acquire_global_lock when an AML Field access requires the

 *    global lock

 * 3) From the external interface, acpi_acquire_global_lock

 *

 ******************************************************************************/

acpi_status

acpi_ex_acquire_mutex_object(u16 timeout,

			     union acpi_operand_object *obj_desc,

			     acpi_thread_id thread_id)

{

	acpi_status status;

	ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex_object, obj_desc);

	if (!obj_desc) {

		return_ACPI_STATUS(AE_BAD_PARAMETER);

	}

	/* Support for multiple acquires by the owning thread */

	if (obj_desc->mutex.thread_id == thread_id) {

		/*

		 * The mutex is already owned by this thread, just increment the

		 * acquisition depth

		 */

		obj_desc->mutex.acquisition_depth++;

		return_ACPI_STATUS(AE_OK);

	}

	/* Acquire the mutex, wait if necessary. Special case for Global Lock */

	if (obj_desc == acpi_gbl_global_lock_mutex) {

		status = acpi_ev_acquire_global_lock(timeout);

	} else {

		status = acpi_ex_system_wait_mutex(obj_desc->mutex.os_mutex,

						   timeout);

	}

	if (ACPI_FAILURE(status)) {

		/* Includes failure from a timeout on time_desc */

		return_ACPI_STATUS(status);

	}

	/* Acquired the mutex: update mutex object */

	obj_desc->mutex.thread_id = thread_id;

	obj_desc->mutex.acquisition_depth = 1;

	obj_desc->mutex.original_sync_level = 0;

	obj_desc->mutex.owner_thread = NULL;	/* Used only for AML Acquire() */

	return_ACPI_STATUS(AE_OK);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_acquire_mutex

 *

 * PARAMETERS:  time_desc           - Timeout integer

 *              obj_desc            - Mutex object

 *              walk_state          - Current method execution state

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Acquire an AML mutex

 *

 ******************************************************************************/

acpi_status

acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,

		      union acpi_operand_object *obj_desc,

		      struct acpi_walk_state *walk_state)

{

	acpi_status status;

	ACPI_FUNCTION_TRACE_PTR(ex_acquire_mutex, obj_desc);

	if (!obj_desc) {

		return_ACPI_STATUS(AE_BAD_PARAMETER);

	}

	/* Must have a valid thread state struct */

	if (!walk_state->thread) {

		ACPI_ERROR((AE_INFO,

			    "Cannot acquire Mutex [%4.4s], null thread info",

			    acpi_ut_get_node_name(obj_desc->mutex.node)));

		return_ACPI_STATUS(AE_AML_INTERNAL);

	}

	/*

	 * Current sync level must be less than or equal to the sync level of the

	 * mutex. This mechanism provides some deadlock prevention

	 */

	if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {

		ACPI_ERROR((AE_INFO,

			    "Cannot acquire Mutex [%4.4s], current SyncLevel is too large (%u)",

			    acpi_ut_get_node_name(obj_desc->mutex.node),

			    walk_state->thread->current_sync_level));

		return_ACPI_STATUS(AE_AML_MUTEX_ORDER);

	}

	status = acpi_ex_acquire_mutex_object((u16) time_desc->integer.value,

					      obj_desc,

					      walk_state->thread->thread_id);

	if (ACPI_SUCCESS(status) && obj_desc->mutex.acquisition_depth == 1) {

		/* Save Thread object, original/current sync levels */

		obj_desc->mutex.owner_thread = walk_state->thread;

		obj_desc->mutex.original_sync_level =

		    walk_state->thread->current_sync_level;

		walk_state->thread->current_sync_level =

		    obj_desc->mutex.sync_level;

		/* Link the mutex to the current thread for force-unlock at method exit */

		acpi_ex_link_mutex(obj_desc, walk_state->thread);

	}

	return_ACPI_STATUS(status);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_release_mutex_object

 *

 * PARAMETERS:  obj_desc            - The object descriptor for this op

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Release a previously acquired Mutex, low level interface.

 *              Provides a common path that supports multiple releases (after

 *              previous multiple acquires) by the same thread.

 *

 * MUTEX:       Interpreter must be locked

 *

 * NOTE: This interface is called from three places:

 * 1) From acpi_ex_release_mutex, via an AML Acquire() operator

 * 2) From acpi_ex_release_global_lock when an AML Field access requires the

 *    global lock

 * 3) From the external interface, acpi_release_global_lock

 *

 ******************************************************************************/

acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc)

{

	acpi_status status = AE_OK;

	ACPI_FUNCTION_TRACE(ex_release_mutex_object);

	if (obj_desc->mutex.acquisition_depth == 0) {

		return_ACPI_STATUS(AE_NOT_ACQUIRED);

	}

	/* Match multiple Acquires with multiple Releases */

	obj_desc->mutex.acquisition_depth--;

	if (obj_desc->mutex.acquisition_depth != 0) {

		/* Just decrement the depth and return */

		return_ACPI_STATUS(AE_OK);

	}

	if (obj_desc->mutex.owner_thread) {

		/* Unlink the mutex from the owner's list */

		acpi_ex_unlink_mutex(obj_desc);

		obj_desc->mutex.owner_thread = NULL;

	}

	/* Release the mutex, special case for Global Lock */

	if (obj_desc == acpi_gbl_global_lock_mutex) {

		status = acpi_ev_release_global_lock();

	} else {

		acpi_os_release_mutex(obj_desc->mutex.os_mutex);

	}

	/* Clear mutex info */

	obj_desc->mutex.thread_id = 0;

	return_ACPI_STATUS(status);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_release_mutex

 *

 * PARAMETERS:  obj_desc            - The object descriptor for this op

 *              walk_state          - Current method execution state

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Release a previously acquired Mutex.

 *

 ******************************************************************************/

acpi_status

acpi_ex_release_mutex(union acpi_operand_object *obj_desc,

		      struct acpi_walk_state *walk_state)

{

	acpi_status status = AE_OK;

	u8 previous_sync_level;

	struct acpi_thread_state *owner_thread;

	ACPI_FUNCTION_TRACE(ex_release_mutex);

	if (!obj_desc) {

		return_ACPI_STATUS(AE_BAD_PARAMETER);

	}

	owner_thread = obj_desc->mutex.owner_thread;

	/* The mutex must have been previously acquired in order to release it */

	if (!owner_thread) {

		ACPI_ERROR((AE_INFO,

			    "Cannot release Mutex [%4.4s], not acquired",

			    acpi_ut_get_node_name(obj_desc->mutex.node)));

		return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);

	}

	/* Must have a valid thread ID */

	if (!walk_state->thread) {

		ACPI_ERROR((AE_INFO,

			    "Cannot release Mutex [%4.4s], null thread info",

			    acpi_ut_get_node_name(obj_desc->mutex.node)));

		return_ACPI_STATUS(AE_AML_INTERNAL);

	}

	/*

	 * The Mutex is owned, but this thread must be the owner.

	 * Special case for Global Lock, any thread can release

	 */

	if ((owner_thread->thread_id != walk_state->thread->thread_id) &&

	    (obj_desc != acpi_gbl_global_lock_mutex)) {

		ACPI_ERROR((AE_INFO,

			    "Thread %u cannot release Mutex [%4.4s] acquired by thread %u",

			    (u32)walk_state->thread->thread_id,

			    acpi_ut_get_node_name(obj_desc->mutex.node),

			    (u32)owner_thread->thread_id));

		return_ACPI_STATUS(AE_AML_NOT_OWNER);

	}

	/*

	 * The sync level of the mutex must be equal to the current sync level. In

	 * other words, the current level means that at least one mutex at that

	 * level is currently being held. Attempting to release a mutex of a

	 * different level can only mean that the mutex ordering rule is being

	 * violated. This behavior is clarified in ACPI 4.0 specification.

	 */

	if (obj_desc->mutex.sync_level != owner_thread->current_sync_level) {

		ACPI_ERROR((AE_INFO,

			    "Cannot release Mutex [%4.4s], SyncLevel mismatch: mutex %u current %u",

			    acpi_ut_get_node_name(obj_desc->mutex.node),

			    obj_desc->mutex.sync_level,

			    walk_state->thread->current_sync_level));

		return_ACPI_STATUS(AE_AML_MUTEX_ORDER);

	}

	/*

	 * Get the previous sync_level from the head of the acquired mutex list.

	 * This handles the case where several mutexes at the same level have been

	 * acquired, but are not released in reverse order.

	 */

	previous_sync_level =

	    owner_thread->acquired_mutex_list->mutex.original_sync_level;

	status = acpi_ex_release_mutex_object(obj_desc);

	if (ACPI_FAILURE(status)) {

		return_ACPI_STATUS(status);

	}

	if (obj_desc->mutex.acquisition_depth == 0) {

		/* Restore the previous sync_level */

		owner_thread->current_sync_level = previous_sync_level;

	}

	return_ACPI_STATUS(status);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_ex_release_all_mutexes

 *

 * PARAMETERS:  thread              - Current executing thread object

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Release all mutexes held by this thread

 *

 * NOTE: This function is called as the thread is exiting the interpreter.

 * Mutexes are not released when an individual control method is exited, but

 * only when the parent thread actually exits the interpreter. This allows one

 * method to acquire a mutex, and a different method to release it, as long as

 * this is performed underneath a single parent control method.

 *

 ******************************************************************************/

void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)

{

	union acpi_operand_object *next = thread->acquired_mutex_list;

	union acpi_operand_object *obj_desc;

	ACPI_FUNCTION_NAME(ex_release_all_mutexes);

	/* Traverse the list of owned mutexes, releasing each one */

	while (next) {

		obj_desc = next;

		next = obj_desc->mutex.next;

		obj_desc->mutex.prev = NULL;

		obj_desc->mutex.next = NULL;

		obj_desc->mutex.acquisition_depth = 0;

		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,

				  "Force-releasing held mutex: %p\n",

				  obj_desc));

		/* Release the mutex, special case for Global Lock */

		if (obj_desc == acpi_gbl_global_lock_mutex) {

			/* Ignore errors */

			(void)acpi_ev_release_global_lock();

		} else {

			acpi_os_release_mutex(obj_desc->mutex.os_mutex);

		}

		/* Mark mutex unowned */

		obj_desc->mutex.owner_thread = NULL;

		obj_desc->mutex.thread_id = 0;

		/* Update Thread sync_level (Last mutex is the important one) */

		thread->current_sync_level =

		    obj_desc->mutex.original_sync_level;

	}

}