Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 828 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/dsmethod.c b/drivers/acpi/acpica/dsmethod.c
new file mode 100644
index 000000000..dd4deb678
--- /dev/null
+++ b/drivers/acpi/acpica/dsmethod.c
@@ -0,0 +1,828 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
+ *
+ * Copyright (C) 2000 - 2018, Intel Corp.
+ *
+ *****************************************************************************/
+
+#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);
+}
+
+/*******************************************************************************
+ *
+ * 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);
+}
+
+/*******************************************************************************
+ *
+ * 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_name name = 0;
+
+	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);
+
+		if (walk_state->method_node) {
+			name = walk_state->method_node->name.integer;
+		} else if (walk_state->deferred_node) {
+			name = walk_state->deferred_node->name.integer;
+		}
+
+		status = acpi_gbl_exception_handler(status, name,
+						    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);
+}
+
+/*******************************************************************************
+ *
+ * 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);
+}
+
+/*******************************************************************************
+ *
+ * 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);
+}
+
+/*******************************************************************************
+ *
+ * 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);
+}
+
+/*******************************************************************************
+ *
+ * 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);
+}
+
+/*******************************************************************************
+ *
+ * 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);
+
+		/*
+		 * 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 */
+
+			(void)acpi_ex_exit_interpreter();
+			acpi_ns_delete_namespace_subtree(walk_state->
+							 method_node);
+			(void)acpi_ex_enter_interpreter();
+
+			/*
+			 * 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) {
+				(void)acpi_ex_exit_interpreter();
+				acpi_ns_delete_namespace_by_owner(method_desc->
+								  method.
+								  owner_id);
+				(void)acpi_ex_enter_interpreter();
+				method_desc->method.info_flags &=
+				    ~ACPI_METHOD_MODIFIED_NAMESPACE;
+			}
+		}
+
+		/*
+		 * 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;
+			}
+		}
+	}
+
+	/* 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;
+}