Release 4.7 drivers/acpi/acpica/dsmethod.c
  
  
/******************************************************************************
 *
 * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
 *
 *****************************************************************************/
/*
 * Copyright (C) 2000 - 2016, 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 "acdispat.h"
#include "acinterp.h"
#include "acnamesp.h"
#include "acparser.h"
#include "amlcode.h"
#include "acdebug.h"
#define _COMPONENT          ACPI_DISPATCHER
ACPI_MODULE_NAME("dsmethod")
/* Local prototypes */
static acpi_status
acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
			     union acpi_parse_object **out_op);
static acpi_status
acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);
/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_auto_serialize_method
 *
 * PARAMETERS:  node                        - Namespace Node of the method
 *              obj_desc                    - Method object attached to node
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse a control method AML to scan for control methods that
 *              need serialization due to the creation of named objects.
 *
 * NOTE: It is a bit of overkill to mark all such methods serialized, since
 * there is only a problem if the method actually blocks during execution.
 * A blocking operation is, for example, a Sleep() operation, or any access
 * to an operation region. However, it is probably not possible to easily
 * detect whether a method will block or not, so we simply mark all suspicious
 * methods as serialized.
 *
 * NOTE2: This code is essentially a generic routine for parsing a single
 * control method.
 *
 ******************************************************************************/
acpi_status
acpi_ds_auto_serialize_method(struct acpi_namespace_node *node,
			      union acpi_operand_object *obj_desc)
{
	acpi_status status;
	union acpi_parse_object *op = NULL;
	struct acpi_walk_state *walk_state;
	ACPI_FUNCTION_TRACE_PTR(ds_auto_serialize_method, node);
	ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
			  "Method auto-serialization parse [%4.4s] %p\n",
			  acpi_ut_get_node_name(node), node));
	/* Create/Init a root op for the method parse tree */
	op = acpi_ps_alloc_op(AML_METHOD_OP, obj_desc->method.aml_start);
	if (!op) {
		return_ACPI_STATUS(AE_NO_MEMORY);
	}
	acpi_ps_set_name(op, node->name.integer);
	op->common.node = node;
	/* Create and initialize a new walk state */
	walk_state =
	    acpi_ds_create_walk_state(node->owner_id, NULL, NULL, NULL);
	if (!walk_state) {
		acpi_ps_free_op(op);
		return_ACPI_STATUS(AE_NO_MEMORY);
	}
	status = acpi_ds_init_aml_walk(walk_state, op, node,
				       obj_desc->method.aml_start,
				       obj_desc->method.aml_length, NULL, 0);
	if (ACPI_FAILURE(status)) {
		acpi_ds_delete_walk_state(walk_state);
		acpi_ps_free_op(op);
		return_ACPI_STATUS(status);
	}
	walk_state->descending_callback = acpi_ds_detect_named_opcodes;
	/* Parse the method, scan for creation of named objects */
	status = acpi_ps_parse_aml(walk_state);
	acpi_ps_delete_parse_tree(op);
	return_ACPI_STATUS(status);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 190 | 92.23% | 1 | 33.33% | 
| lv zheng | lv zheng | 16 | 7.77% | 2 | 66.67% | 
 | Total | 206 | 100.00% | 3 | 100.00% | 
/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_detect_named_opcodes
 *
 * PARAMETERS:  walk_state      - Current state of the parse tree walk
 *              out_op          - Unused, required for parser interface
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Descending callback used during the loading of ACPI tables.
 *              Currently used to detect methods that must be marked serialized
 *              in order to avoid problems with the creation of named objects.
 *
 ******************************************************************************/
static acpi_status
acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
			     union acpi_parse_object **out_op)
{
	ACPI_FUNCTION_NAME(acpi_ds_detect_named_opcodes);
	/* We are only interested in opcodes that create a new name */
	if (!
	    (walk_state->op_info->
	     flags & (AML_NAMED | AML_CREATE | AML_FIELD))) {
		return (AE_OK);
	}
	/*
         * At this point, we know we have a Named object opcode.
         * Mark the method as serialized. Later code will create a mutex for
         * this method to enforce serialization.
         *
         * Note, ACPI_METHOD_IGNORE_SYNC_LEVEL flag means that we will ignore the
         * Sync Level mechanism for this method, even though it is now serialized.
         * Otherwise, there can be conflicts with existing ASL code that actually
         * uses sync levels.
         */
	walk_state->method_desc->method.sync_level = 0;
	walk_state->method_desc->method.info_flags |=
	    (ACPI_METHOD_SERIALIZED | ACPI_METHOD_IGNORE_SYNC_LEVEL);
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			  "Method serialized [%4.4s] %p - [%s] (%4.4X)\n",
			  walk_state->method_node->name.ascii,
			  walk_state->method_node, walk_state->op_info->name,
			  walk_state->opcode));
	/* Abort the parse, no need to examine this method any further */
	return (AE_CTRL_TERMINATE);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 104 | 93.69% | 2 | 66.67% | 
| lv zheng | lv zheng | 7 | 6.31% | 1 | 33.33% | 
 | Total | 111 | 100.00% | 3 | 100.00% | 
/*******************************************************************************
 *
 * 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 debugger 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)
{
	u32 aml_offset;
	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.
                 */
		aml_offset = (u32)ACPI_PTR_DIFF(walk_state->aml,
						walk_state->parser_state.
						aml_start);
		status = acpi_gbl_exception_handler(status,
						    walk_state->method_node ?
						    walk_state->method_node->
						    name.integer : 0,
						    walk_state->opcode,
						    aml_offset, NULL);
		acpi_ex_enter_interpreter();
	}
	acpi_ds_clear_implicit_return(walk_state);
	if (ACPI_FAILURE(status)) {
		acpi_ds_dump_method_stack(status, walk_state, walk_state->op);
		/* Display method locals/args if debugger is present */
#ifdef ACPI_DEBUGGER
		acpi_db_dump_method_info(status, walk_state);
#endif
	}
	return (status);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 106 | 73.10% | 1 | 20.00% | 
| lv zheng | lv zheng | 34 | 23.45% | 3 | 60.00% | 
| lin ming | lin ming | 5 | 3.45% | 1 | 20.00% | 
 | Total | 145 | 100.00% | 5 | 100.00% | 
/*******************************************************************************
 *
 * 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)) {
		acpi_ut_delete_object_desc(mutex_desc);
		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);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 96 | 95.05% | 2 | 66.67% | 
| tim gardner | tim gardner | 5 | 4.95% | 1 | 33.33% | 
 | Total | 101 | 100.00% | 3 | 100.00% | 
/*******************************************************************************
 *
 * 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);
	}
	acpi_ex_start_trace_method(method_node, obj_desc, walk_state);
	/* 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.info_flags & ACPI_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.
                 *
                 * If the method was auto-serialized, we just ignore the sync level
                 * mechanism, because auto-serialization of methods can interfere
                 * with ASL code that actually uses sync levels.
                 *
                 * Top-level method invocation has no walk state at this point
                 */
		if (walk_state &&
		    (!(obj_desc->method.
		       info_flags & ACPI_METHOD_IGNORE_SYNC_LEVEL))
		    && (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 (%u)",
				    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;
				/*
                                 * Update the current sync_level only if this is not an auto-
                                 * serialized method. In the auto case, we have to ignore
                                 * the sync level for the method mutex (created for the
                                 * auto-serialization) because we have no idea of what the
                                 * sync level should be. Therefore, just ignore it.
                                 */
				if (!(obj_desc->method.info_flags &
				      ACPI_METHOD_IGNORE_SYNC_LEVEL)) {
					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;
				obj_desc->method.mutex->mutex.thread_id =
				    acpi_os_get_thread_id();
			}
		}
		/* 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++;
	acpi_method_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);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 299 | 65.43% | 9 | 36.00% | 
| pre-git | pre-git | 43 | 9.41% | 1 | 4.00% | 
| len brown | len brown | 30 | 6.56% | 2 | 8.00% | 
| linus torvalds | linus torvalds | 28 | 6.13% | 3 | 12.00% | 
| david box | david box | 16 | 3.50% | 1 | 4.00% | 
| prarit bhargava | prarit bhargava | 13 | 2.84% | 1 | 4.00% | 
| andy grover | andy grover | 13 | 2.84% | 3 | 12.00% | 
| lv zheng | lv zheng | 12 | 2.63% | 3 | 12.00% | 
| lin ming | lin ming | 2 | 0.44% | 1 | 4.00% | 
| alexey starikovskiy | alexey starikovskiy | 1 | 0.22% | 1 | 4.00% | 
 | Total | 457 | 100.00% | 25 | 100.00% | 
/*******************************************************************************
 *
 * 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\n",
			  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) {
		status = AE_NO_MEMORY;
		goto cleanup;
	}
	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\n",
			  method_node->name.ascii, next_walk_state));
	/* Invoke an internal method if necessary */
	if (obj_desc->method.info_flags & ACPI_METHOD_INTERNAL_ONLY) {
		status =
		    obj_desc->method.dispatch.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);
	acpi_ds_delete_walk_state(next_walk_state);
	return_ACPI_STATUS(status);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| pre-git | pre-git | 162 | 41.97% | 2 | 9.09% | 
| linus torvalds | linus torvalds | 95 | 24.61% | 3 | 13.64% | 
| robert moore | robert moore | 58 | 15.03% | 7 | 31.82% | 
| len brown | len brown | 43 | 11.14% | 3 | 13.64% | 
| andy grover | andy grover | 10 | 2.59% | 3 | 13.64% | 
| valery podrezov | valery podrezov | 9 | 2.33% | 1 | 4.55% | 
| jesper juhl | jesper juhl | 5 | 1.30% | 1 | 4.55% | 
| lin ming | lin ming | 4 | 1.04% | 2 | 9.09% | 
 | Total | 386 | 100.00% | 22 | 100.00% | 
/*******************************************************************************
 *
 * 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\n",
			  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\n",
			  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);
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| len brown | len brown | 59 | 36.65% | 2 | 16.67% | 
| pre-git | pre-git | 55 | 34.16% | 3 | 25.00% | 
| robert moore | robert moore | 24 | 14.91% | 3 | 25.00% | 
| linus torvalds | linus torvalds | 20 | 12.42% | 2 | 16.67% | 
| andy grover | andy grover | 3 | 1.86% | 2 | 16.67% | 
 | Total | 161 | 100.00% | 12 | 100.00% | 
/*******************************************************************************
 *
 * 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 = 0;
			}
		}
		/*
                 * Delete any namespace objects created anywhere within the
                 * namespace by the execution of this method. Unless:
                 * 1) This method is a module-level executable code method, in which
                 *    case we want make the objects permanent.
                 * 2) There are other threads executing the method, in which case we
                 *    will wait until the last thread has completed.
                 */
		if (!(method_desc->method.info_flags & ACPI_METHOD_MODULE_LEVEL)
		    && (method_desc->method.thread_count == 1)) {
			/* Delete any direct children of (created by) this method */
			acpi_ns_delete_namespace_subtree(walk_state->
							 method_node);
			/*
                         * Delete any objects that were created by this method
                         * elsewhere in the namespace (if any were created).
                         * Use of the ACPI_METHOD_MODIFIED_NAMESPACE optimizes the
                         * deletion such that we don't have to perform an entire
                         * namespace walk for every control method execution.
                         */
			if (method_desc->method.
			    info_flags & ACPI_METHOD_MODIFIED_NAMESPACE) {
				acpi_ns_delete_namespace_by_owner(method_desc->
								  method.
								  owner_id);
				method_desc->method.info_flags &=
				    ~ACPI_METHOD_MODIFIED_NAMESPACE;
			}
		}
	}
	/* 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, %u threads remaining\n",
				  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 marking the method as serialized.
                 */
		if (method_desc->method.
		    info_flags & ACPI_METHOD_SERIALIZED_PENDING) {
			if (walk_state) {
				ACPI_INFO(("Marking method %4.4s as Serialized "
					   "because of AE_ALREADY_EXISTS error",
					   walk_state->method_node->name.
					   ascii));
			}
			/*
                         * Method tried to create an object twice and was marked as
                         * "pending serialized". The probable cause is that the method
                         * cannot handle reentrancy.
                         *
                         * The method was created as not_serialized, but it tried to create
                         * a named object and then blocked, causing the second thread
                         * entrance to begin and then fail. Workaround this problem by
                         * marking the method permanently as Serialized when the last
                         * thread exits here.
                         */
			method_desc->method.info_flags &=
			    ~ACPI_METHOD_SERIALIZED_PENDING;
			method_desc->method.info_flags |=
			    (ACPI_METHOD_SERIALIZED |
			     ACPI_METHOD_IGNORE_SYNC_LEVEL);
			method_desc->method.sync_level = 0;
		}
		/* No more threads, we can free the owner_id */
		if (!
		    (method_desc->method.
		     info_flags & ACPI_METHOD_MODULE_LEVEL)) {
			acpi_ut_release_owner_id(&method_desc->method.owner_id);
		}
	}
	acpi_ex_stop_trace_method((struct acpi_namespace_node *)method_desc->
				  method.node, method_desc, walk_state);
	return_VOID;
}
Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 134 | 37.22% | 10 | 43.48% | 
| lin ming | lin ming | 98 | 27.22% | 3 | 13.04% | 
| pre-git | pre-git | 38 | 10.56% | 2 | 8.70% | 
| len brown | len brown | 30 | 8.33% | 1 | 4.35% | 
| alexey starikovskiy | alexey starikovskiy | 18 | 5.00% | 1 | 4.35% | 
| lv zheng | lv zheng | 18 | 5.00% | 2 | 8.70% | 
| andy grover | andy grover | 18 | 5.00% | 3 | 13.04% | 
| linus torvalds | linus torvalds | 6 | 1.67% | 1 | 4.35% | 
 | Total | 360 | 100.00% | 23 | 100.00% | 
Overall Contributors
 | Person | Tokens | Prop | Commits | CommitProp | 
| robert moore | robert moore | 1054 | 52.81% | 23 | 36.51% | 
| pre-git | pre-git | 312 | 15.63% | 3 | 4.76% | 
| len brown | len brown | 166 | 8.32% | 8 | 12.70% | 
| linus torvalds | linus torvalds | 150 | 7.52% | 3 | 4.76% | 
| lin ming | lin ming | 109 | 5.46% | 5 | 7.94% | 
| lv zheng | lv zheng | 91 | 4.56% | 9 | 14.29% | 
| andy grover | andy grover | 46 | 2.30% | 4 | 6.35% | 
| alexey starikovskiy | alexey starikovskiy | 19 | 0.95% | 2 | 3.17% | 
| david box | david box | 16 | 0.80% | 1 | 1.59% | 
| prarit bhargava | prarit bhargava | 13 | 0.65% | 1 | 1.59% | 
| valery podrezov | valery podrezov | 9 | 0.45% | 1 | 1.59% | 
| tim gardner | tim gardner | 5 | 0.25% | 1 | 1.59% | 
| jesper juhl | jesper juhl | 5 | 0.25% | 1 | 1.59% | 
| patrick mochel | patrick mochel | 1 | 0.05% | 1 | 1.59% | 
 | Total | 1996 | 100.00% | 63 | 100.00% | 
  
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