/******************************************************************************
   *
   * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
   *
   *****************************************************************************/
  
  /*

   * Copyright (C) 2000 - 2008, 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 <acpi/acpi.h>

  #include "accommon.h"
  #include "amlcode.h"
  #include "acdispat.h"
  #include "acinterp.h"
  #include "acnamesp.h"

  #ifdef	ACPI_DISASSEMBLER

  #include <acpi/acdisasm.h>

  #endif

  #define _COMPONENT          ACPI_DISPATCHER

  ACPI_MODULE_NAME("dsmethod")

  /* Local prototypes */
  static acpi_status
  acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);

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

   * FUNCTION:    acpi_ds_method_error
   *
   * PARAMETERS:  Status          - Execution status
   *              walk_state      - Current state
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Called on method error. Invoke the global exception handler if
   *              present, dump the method data if the disassembler is configured
   *
   *              Note: Allows the exception handler to change the status code
   *
   ******************************************************************************/

  acpi_status
  acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
  {
  	ACPI_FUNCTION_ENTRY();
  
  	/* Ignore AE_OK and control exception codes */
  
  	if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
  		return (status);
  	}
  
  	/* Invoke the global exception handler */
  
  	if (acpi_gbl_exception_handler) {

  		/* Exit the interpreter, allow handler to execute methods */
  
  		acpi_ex_exit_interpreter();
  
  		/*
  		 * Handler can map the exception code to anything it wants, including
  		 * AE_OK, in which case the executing method will not be aborted.
  		 */
  		status = acpi_gbl_exception_handler(status,
  						    walk_state->method_node ?
  						    walk_state->method_node->
  						    name.integer : 0,
  						    walk_state->opcode,
  						    walk_state->aml_offset,
  						    NULL);

  		acpi_ex_enter_interpreter();

  	}

  
  	acpi_ds_clear_implicit_return(walk_state);

  #ifdef ACPI_DISASSEMBLER
  	if (ACPI_FAILURE(status)) {

  		/* Display method locals/args if disassembler is present */
  
  		acpi_dm_dump_method_info(status, walk_state, walk_state->op);
  	}
  #endif
  
  	return (status);
  }
  
  /*******************************************************************************
   *

   * FUNCTION:    acpi_ds_create_method_mutex
   *
   * PARAMETERS:  obj_desc            - The method object
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Create a mutex object for a serialized control method
   *
   ******************************************************************************/
  
  static acpi_status
  acpi_ds_create_method_mutex(union acpi_operand_object *method_desc)
  {
  	union acpi_operand_object *mutex_desc;
  	acpi_status status;

  	ACPI_FUNCTION_TRACE(ds_create_method_mutex);

  
  	/* Create the new mutex object */
  
  	mutex_desc = acpi_ut_create_internal_object(ACPI_TYPE_MUTEX);
  	if (!mutex_desc) {
  		return_ACPI_STATUS(AE_NO_MEMORY);
  	}
  
  	/* Create the actual OS Mutex */
  
  	status = acpi_os_create_mutex(&mutex_desc->mutex.os_mutex);
  	if (ACPI_FAILURE(status)) {
  		return_ACPI_STATUS(status);
  	}
  
  	mutex_desc->mutex.sync_level = method_desc->method.sync_level;
  	method_desc->method.mutex = mutex_desc;
  	return_ACPI_STATUS(AE_OK);
  }
  
  /*******************************************************************************
   *

   * FUNCTION:    acpi_ds_begin_method_execution
   *
   * PARAMETERS:  method_node         - Node of the method
   *              obj_desc            - The method object

   *              walk_state          - current state, NULL if not yet executing
   *                                    a method.

   *
   * RETURN:      Status
   *
   * DESCRIPTION: Prepare a method for execution.  Parses the method if necessary,
   *              increments the thread count, and waits at the method semaphore
   *              for clearance to execute.
   *
   ******************************************************************************/

  acpi_status

  acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
  			       union acpi_operand_object *obj_desc,
  			       struct acpi_walk_state *walk_state)

  {

  	acpi_status status = AE_OK;

  	ACPI_FUNCTION_TRACE_PTR(ds_begin_method_execution, method_node);

  
  	if (!method_node) {

  		return_ACPI_STATUS(AE_NULL_ENTRY);

  	}

  	/* Prevent wraparound of thread count */
  
  	if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {

  		ACPI_ERROR((AE_INFO,
  			    "Method reached maximum reentrancy limit (255)"));

  		return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
  	}

  	/*

  	 * If this method is serialized, we need to acquire the method mutex.

  	 */

  	if (obj_desc->method.method_flags & AML_METHOD_SERIALIZED) {

  		/*

  		 * Create a mutex for the method if it is defined to be Serialized
  		 * and a mutex has not already been created. We defer the mutex creation
  		 * until a method is actually executed, to minimize the object count

  		 */

  		if (!obj_desc->method.mutex) {
  			status = acpi_ds_create_method_mutex(obj_desc);
  			if (ACPI_FAILURE(status)) {
  				return_ACPI_STATUS(status);

  			}
  		}
  
  		/*

  		 * The current_sync_level (per-thread) must be less than or equal to
  		 * the sync level of the method. This mechanism provides some
  		 * deadlock prevention
  		 *
  		 * Top-level method invocation has no walk state at this point

  		 */

  		if (walk_state &&
  		    (walk_state->thread->current_sync_level >
  		     obj_desc->method.mutex->mutex.sync_level)) {
  			ACPI_ERROR((AE_INFO,
  				    "Cannot acquire Mutex for method [%4.4s], current SyncLevel is too large (%d)",
  				    acpi_ut_get_node_name(method_node),
  				    walk_state->thread->current_sync_level));
  
  			return_ACPI_STATUS(AE_AML_MUTEX_ORDER);

  		}

  
  		/*
  		 * Obtain the method mutex if necessary. Do not acquire mutex for a
  		 * recursive call.
  		 */

  		if (!walk_state ||

  		    !obj_desc->method.mutex->mutex.thread_id ||
  		    (walk_state->thread->thread_id !=
  		     obj_desc->method.mutex->mutex.thread_id)) {

  			/*
  			 * Acquire the method mutex. This releases the interpreter if we
  			 * block (and reacquires it before it returns)
  			 */
  			status =
  			    acpi_ex_system_wait_mutex(obj_desc->method.mutex->
  						      mutex.os_mutex,
  						      ACPI_WAIT_FOREVER);
  			if (ACPI_FAILURE(status)) {
  				return_ACPI_STATUS(status);
  			}
  
  			/* Update the mutex and walk info and save the original sync_level */
  
  			if (walk_state) {
  				obj_desc->method.mutex->mutex.
  				    original_sync_level =
  				    walk_state->thread->current_sync_level;

  				obj_desc->method.mutex->mutex.thread_id =
  				    walk_state->thread->thread_id;

  				walk_state->thread->current_sync_level =
  				    obj_desc->method.sync_level;
  			} else {
  				obj_desc->method.mutex->mutex.
  				    original_sync_level =
  				    obj_desc->method.mutex->mutex.sync_level;
  			}
  		}
  
  		/* Always increase acquisition depth */
  
  		obj_desc->method.mutex->mutex.acquisition_depth++;

  	}
  
  	/*

  	 * Allocate an Owner ID for this method, only if this is the first thread
  	 * to begin concurrent execution. We only need one owner_id, even if the
  	 * method is invoked recursively.
  	 */
  	if (!obj_desc->method.owner_id) {
  		status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
  		if (ACPI_FAILURE(status)) {

  			goto cleanup;

  		}
  	}
  
  	/*

  	 * Increment the method parse tree thread count since it has been
  	 * reentered one more time (even if it is the same thread)
  	 */
  	obj_desc->method.thread_count++;

  	return_ACPI_STATUS(status);

  
        cleanup:

  	/* On error, must release the method mutex (if present) */

  	if (obj_desc->method.mutex) {
  		acpi_os_release_mutex(obj_desc->method.mutex->mutex.os_mutex);

  	}
  	return_ACPI_STATUS(status);

  }

  /*******************************************************************************
   *
   * FUNCTION:    acpi_ds_call_control_method
   *
   * PARAMETERS:  Thread              - Info for this thread
   *              this_walk_state     - Current walk state
   *              Op                  - Current Op to be walked
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Transfer execution to a called control method
   *
   ******************************************************************************/
  
  acpi_status

  acpi_ds_call_control_method(struct acpi_thread_state *thread,
  			    struct acpi_walk_state *this_walk_state,
  			    union acpi_parse_object *op)

  {

  	acpi_status status;
  	struct acpi_namespace_node *method_node;
  	struct acpi_walk_state *next_walk_state = NULL;
  	union acpi_operand_object *obj_desc;

  	struct acpi_evaluate_info *info;

  	u32 i;

  	ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);

  	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,

  			  "Calling method %p, currentstate=%p
  ",

  			  this_walk_state->prev_op, this_walk_state));

  
  	/*
  	 * Get the namespace entry for the control method we are about to call
  	 */
  	method_node = this_walk_state->method_call_node;
  	if (!method_node) {

  		return_ACPI_STATUS(AE_NULL_ENTRY);

  	}

  	obj_desc = acpi_ns_get_attached_object(method_node);

  	if (!obj_desc) {

  		return_ACPI_STATUS(AE_NULL_OBJECT);

  	}

  	/* Init for new method, possibly wait on method mutex */

  	status = acpi_ds_begin_method_execution(method_node, obj_desc,

  						this_walk_state);

  	if (ACPI_FAILURE(status)) {

  		return_ACPI_STATUS(status);

  	}

  	/* Begin method parse/execution. Create a new walk state */

  	next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
  						    NULL, obj_desc, thread);

  	if (!next_walk_state) {
  		status = AE_NO_MEMORY;
  		goto cleanup;
  	}

  	/*
  	 * The resolved arguments were put on the previous walk state's operand

  	 * stack. Operands on the previous walk state stack always
  	 * start at index 0. Also, null terminate the list of arguments

  	 */

  	this_walk_state->operands[this_walk_state->num_operands] = NULL;

  	/*
  	 * Allocate and initialize the evaluation information block
  	 * TBD: this is somewhat inefficient, should change interface to
  	 * ds_init_aml_walk. For now, keeps this struct off the CPU stack
  	 */
  	info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
  	if (!info) {
  		return_ACPI_STATUS(AE_NO_MEMORY);
  	}
  
  	info->parameters = &this_walk_state->operands[0];

  	status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
  				       obj_desc->method.aml_start,

  				       obj_desc->method.aml_length, info,
  				       ACPI_IMODE_EXECUTE);

  
  	ACPI_FREE(info);

  	if (ACPI_FAILURE(status)) {

  		goto cleanup;
  	}
  
  	/*
  	 * Delete the operands on the previous walkstate operand stack
  	 * (they were copied to new objects)
  	 */
  	for (i = 0; i < obj_desc->method.param_count; i++) {

  		acpi_ut_remove_reference(this_walk_state->operands[i]);
  		this_walk_state->operands[i] = NULL;

  	}
  
  	/* Clear the operand stack */
  
  	this_walk_state->num_operands = 0;

  	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,

  			  "**** Begin nested execution of [%4.4s] **** WalkState=%p
  ",
  			  method_node->name.ascii, next_walk_state));

  	/* Invoke an internal method if necessary */

  	if (obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY) {

  		status = obj_desc->method.extra.implementation(next_walk_state);

  		if (status == AE_OK) {
  			status = AE_CTRL_TERMINATE;
  		}

  	}

  	return_ACPI_STATUS(status);

  
        cleanup:

  	/* On error, we must terminate the method properly */

  	acpi_ds_terminate_control_method(obj_desc, next_walk_state);
  	if (next_walk_state) {
  		acpi_ds_delete_walk_state(next_walk_state);
  	}

  	return_ACPI_STATUS(status);

  }

  /*******************************************************************************
   *
   * FUNCTION:    acpi_ds_restart_control_method
   *
   * PARAMETERS:  walk_state          - State for preempted method (caller)
   *              return_desc         - Return value from the called method
   *
   * RETURN:      Status
   *
   * DESCRIPTION: Restart a method that was preempted by another (nested) method
   *              invocation.  Handle the return value (if any) from the callee.
   *
   ******************************************************************************/
  
  acpi_status

  acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
  			       union acpi_operand_object *return_desc)

  {

  	acpi_status status;

  	int same_as_implicit_return;

  	ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);

  	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,

  			  "****Restart [%4.4s] Op %p ReturnValueFromCallee %p
  ",

  			  acpi_ut_get_node_name(walk_state->method_node),

  			  walk_state->method_call_op, return_desc));

  	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,

  			  "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p
  ",

  			  walk_state->return_used,
  			  walk_state->results, walk_state));

  
  	/* Did the called method return a value? */
  
  	if (return_desc) {

  		/* Is the implicit return object the same as the return desc? */
  
  		same_as_implicit_return =
  		    (walk_state->implicit_return_obj == return_desc);

  		/* Are we actually going to use the return value? */
  
  		if (walk_state->return_used) {

  			/* Save the return value from the previous method */

  			status = acpi_ds_result_push(return_desc, walk_state);
  			if (ACPI_FAILURE(status)) {
  				acpi_ut_remove_reference(return_desc);
  				return_ACPI_STATUS(status);

  			}
  
  			/*
  			 * Save as THIS method's return value in case it is returned
  			 * immediately to yet another method
  			 */
  			walk_state->return_desc = return_desc;
  		}
  
  		/*

  		 * The following code is the optional support for the so-called
  		 * "implicit return". Some AML code assumes that the last value of the
  		 * method is "implicitly" returned to the caller, in the absence of an
  		 * explicit return value.
  		 *
  		 * Just save the last result of the method as the return value.
  		 *

  		 * NOTE: this is optional because the ASL language does not actually
  		 * support this behavior.
  		 */

  		else if (!acpi_ds_do_implicit_return

  			 (return_desc, walk_state, FALSE)
  			 || same_as_implicit_return) {

  			/*
  			 * Delete the return value if it will not be used by the

  			 * calling method or remove one reference if the explicit return
  			 * is the same as the implicit return value.

  			 */

  			acpi_ut_remove_reference(return_desc);

  		}
  	}

  	return_ACPI_STATUS(AE_OK);

  }

  /*******************************************************************************
   *
   * FUNCTION:    acpi_ds_terminate_control_method
   *

   * PARAMETERS:  method_desc         - Method object
   *              walk_state          - State associated with the method

   *

   * RETURN:      None

   *
   * DESCRIPTION: Terminate a control method.  Delete everything that the method
   *              created, delete all locals and arguments, and delete the parse
   *              tree if requested.
   *

   * MUTEX:       Interpreter is locked
   *

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

  void
  acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
  				 struct acpi_walk_state *walk_state)

  {

  	ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);

  	/* method_desc is required, walk_state is optional */

  	if (!method_desc) {

  		return_VOID;

  	}

  	if (walk_state) {

  		/* Delete all arguments and locals */
  
  		acpi_ds_method_data_delete_all(walk_state);

  		/*
  		 * If method is serialized, release the mutex and restore the
  		 * current sync level for this thread
  		 */
  		if (method_desc->method.mutex) {

  			/* Acquisition Depth handles recursive calls */

  			method_desc->method.mutex->mutex.acquisition_depth--;
  			if (!method_desc->method.mutex->mutex.acquisition_depth) {
  				walk_state->thread->current_sync_level =
  				    method_desc->method.mutex->mutex.
  				    original_sync_level;

  				acpi_os_release_mutex(method_desc->method.
  						      mutex->mutex.os_mutex);

  				method_desc->method.mutex->mutex.thread_id = NULL;

  			}

  		}

  		/*

  		 * Delete any namespace objects created anywhere within the
  		 * namespace by the execution of this method. Unless this method
  		 * is a module-level executable code method, in which case we
  		 * want make the objects permanent.

  		 */

  		if (!(method_desc->method.flags & AOPOBJ_MODULE_LEVEL)) {
  			acpi_ns_delete_namespace_by_owner(method_desc->method.
  							  owner_id);
  		}

  	}

  	/* Decrement the thread count on the method */
  
  	if (method_desc->method.thread_count) {
  		method_desc->method.thread_count--;
  	} else {
  		ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
  	}

  
  	/* Are there any other threads currently executing this method? */

  	if (method_desc->method.thread_count) {

  		/*
  		 * Additional threads. Do not release the owner_id in this case,
  		 * we immediately reuse it for the next thread executing this method
  		 */

  		ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,

  				  "*** Completed execution of one thread, %d threads remaining
  ",

  				  method_desc->method.thread_count));

  	} else {
  		/* This is the only executing thread for this method */

  		/*
  		 * Support to dynamically change a method from not_serialized to

  		 * Serialized if it appears that the method is incorrectly written and

  		 * does not support multiple thread execution. The best example of this
  		 * is if such a method creates namespace objects and blocks. A second

  		 * thread will fail with an AE_ALREADY_EXISTS exception
  		 *
  		 * This code is here because we must wait until the last thread exits
  		 * before creating the synchronization semaphore.
  		 */

  		if ((method_desc->method.method_flags & AML_METHOD_SERIALIZED)
  		    && (!method_desc->method.mutex)) {

  			(void)acpi_ds_create_method_mutex(method_desc);

  		}

  		/* No more threads, we can free the owner_id */

  		if (!(method_desc->method.flags & AOPOBJ_MODULE_LEVEL)) {
  			acpi_ut_release_owner_id(&method_desc->method.owner_id);
  		}

  	}

  	return_VOID;

  }