drivers/acpi/acpica/nsaccess.c - kernel/bruno - Git at Google

 /*******************************************************************************
  *
  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
  *
  ******************************************************************************/

 /*
  * 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 <acpi/acpi.h>
 #include "accommon.h"
 #include "amlcode.h"
 #include "acnamesp.h"
 #include "acdispat.h"

 #define _COMPONENT          ACPI_NAMESPACE
 ACPI_MODULE_NAME("nsaccess")

 /*******************************************************************************
  *
  * FUNCTION:    acpi_ns_root_initialize
  *
  * PARAMETERS:  None
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Allocate and initialize the default root named objects
  *
  * MUTEX:       Locks namespace for entire execution
  *
  ******************************************************************************/
 acpi_status acpi_ns_root_initialize(void)
 {
 	acpi_status status;
 	const struct acpi_predefined_names *init_val = NULL;
 	struct acpi_namespace_node *new_node;
 	union acpi_operand_object *obj_desc;
 	acpi_string val = NULL;

 	ACPI_FUNCTION_TRACE(ns_root_initialize);

 	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 	if (ACPI_FAILURE(status)) {
 		return_ACPI_STATUS(status);
 	}

 	/*
 	 * The global root ptr is initially NULL, so a non-NULL value indicates
 	 * that acpi_ns_root_initialize() has already been called; just return.
 	 */
 	if (acpi_gbl_root_node) {
 		status = AE_OK;
 		goto unlock_and_exit;
 	}

 	/*
 	 * Tell the rest of the subsystem that the root is initialized
 	 * (This is OK because the namespace is locked)
 	 */
 	acpi_gbl_root_node = &acpi_gbl_root_node_struct;

 	/* Enter the pre-defined names in the name table */

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 			  "Entering predefined entries into namespace\n"));

 	for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {

 		/* _OSI is optional for now, will be permanent later */

 		if (!strcmp(init_val->name, "_OSI")
 		    && !acpi_gbl_create_osi_method) {
 			continue;
 		}

 		status = acpi_ns_lookup(NULL, init_val->name, init_val->type,
 					ACPI_IMODE_LOAD_PASS2,
 					ACPI_NS_NO_UPSEARCH, NULL, &new_node);
 		if (ACPI_FAILURE(status)) {
 			ACPI_EXCEPTION((AE_INFO, status,
 					"Could not create predefined name %s",
 					init_val->name));
 			continue;
 		}

 		/*
 		 * Name entered successfully. If entry in pre_defined_names[] specifies
 		 * an initial value, create the initial value.
 		 */
 		if (init_val->val) {
 			status = acpi_os_predefined_override(init_val, &val);
 			if (ACPI_FAILURE(status)) {
 				ACPI_ERROR((AE_INFO,
 					    "Could not override predefined %s",
 					    init_val->name));
 			}

 			if (!val) {
 				val = init_val->val;
 			}

 			/*
 			 * Entry requests an initial value, allocate a
 			 * descriptor for it.
 			 */
 			obj_desc =
 			    acpi_ut_create_internal_object(init_val->type);
 			if (!obj_desc) {
 				status = AE_NO_MEMORY;
 				goto unlock_and_exit;
 			}

 			/*
 			 * Convert value string from table entry to
 			 * internal representation. Only types actually
 			 * used for initial values are implemented here.
 			 */
 			switch (init_val->type) {
 			case ACPI_TYPE_METHOD:

 				obj_desc->method.param_count =
 				    (u8) ACPI_TO_INTEGER(val);
 				obj_desc->common.flags |= AOPOBJ_DATA_VALID;

 #if defined (ACPI_ASL_COMPILER)

 				/* Save the parameter count for the iASL compiler */

 				new_node->value = obj_desc->method.param_count;
 #else
 				/* Mark this as a very SPECIAL method */

 				obj_desc->method.info_flags =
 				    ACPI_METHOD_INTERNAL_ONLY;
 				obj_desc->method.dispatch.implementation =
 				    acpi_ut_osi_implementation;
 #endif
 				break;

 			case ACPI_TYPE_INTEGER:

 				obj_desc->integer.value = ACPI_TO_INTEGER(val);
 				break;

 			case ACPI_TYPE_STRING:

 				/* Build an object around the static string */

 				obj_desc->string.length = (u32)strlen(val);
 				obj_desc->string.pointer = val;
 				obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
 				break;

 			case ACPI_TYPE_MUTEX:

 				obj_desc->mutex.node = new_node;
 				obj_desc->mutex.sync_level =
 				    (u8) (ACPI_TO_INTEGER(val) - 1);

 				/* Create a mutex */

 				status =
 				    acpi_os_create_mutex(&obj_desc->mutex.
 							 os_mutex);
 				if (ACPI_FAILURE(status)) {
 					acpi_ut_remove_reference(obj_desc);
 					goto unlock_and_exit;
 				}

 				/* Special case for ACPI Global Lock */

 				if (strcmp(init_val->name, "_GL_") == 0) {
 					acpi_gbl_global_lock_mutex = obj_desc;

 					/* Create additional counting semaphore for global lock */

 					status =
 					    acpi_os_create_semaphore(1, 0,
 								     &acpi_gbl_global_lock_semaphore);
 					if (ACPI_FAILURE(status)) {
 						acpi_ut_remove_reference
 						    (obj_desc);
 						goto unlock_and_exit;
 					}
 				}
 				break;

 			default:

 				ACPI_ERROR((AE_INFO,
 					    "Unsupported initial type value 0x%X",
 					    init_val->type));
 				acpi_ut_remove_reference(obj_desc);
 				obj_desc = NULL;
 				continue;
 			}

 			/* Store pointer to value descriptor in the Node */

 			status = acpi_ns_attach_object(new_node, obj_desc,
 						       obj_desc->common.type);

 			/* Remove local reference to the object */

 			acpi_ut_remove_reference(obj_desc);
 		}
 	}

 unlock_and_exit:
 	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);

 	/* Save a handle to "_GPE", it is always present */

 	if (ACPI_SUCCESS(status)) {
 		status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
 					  &acpi_gbl_fadt_gpe_device);
 	}

 	return_ACPI_STATUS(status);
 }

 /*******************************************************************************
  *
  * FUNCTION:    acpi_ns_lookup
  *
  * PARAMETERS:  scope_info      - Current scope info block
  *              pathname        - Search pathname, in internal format
  *                                (as represented in the AML stream)
  *              type            - Type associated with name
  *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
  *              flags           - Flags describing the search restrictions
  *              walk_state      - Current state of the walk
  *              return_node     - Where the Node is placed (if found
  *                                or created successfully)
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Find or enter the passed name in the name space.
  *              Log an error if name not found in Exec mode.
  *
  * MUTEX:       Assumes namespace is locked.
  *
  ******************************************************************************/

 acpi_status
 acpi_ns_lookup(union acpi_generic_state *scope_info,
 	       char *pathname,
 	       acpi_object_type type,
 	       acpi_interpreter_mode interpreter_mode,
 	       u32 flags,
 	       struct acpi_walk_state *walk_state,
 	       struct acpi_namespace_node **return_node)
 {
 	acpi_status status;
 	char *path = pathname;
 	struct acpi_namespace_node *prefix_node;
 	struct acpi_namespace_node *current_node = NULL;
 	struct acpi_namespace_node *this_node = NULL;
 	u32 num_segments;
 	u32 num_carats;
 	acpi_name simple_name;
 	acpi_object_type type_to_check_for;
 	acpi_object_type this_search_type;
 	u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
 	u32 local_flags;

 	ACPI_FUNCTION_TRACE(ns_lookup);

 	if (!return_node) {
 		return_ACPI_STATUS(AE_BAD_PARAMETER);
 	}

 	local_flags = flags &
 	    ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
 	      ACPI_NS_SEARCH_PARENT);
 	*return_node = ACPI_ENTRY_NOT_FOUND;
 	acpi_gbl_ns_lookup_count++;

 	if (!acpi_gbl_root_node) {
 		return_ACPI_STATUS(AE_NO_NAMESPACE);
 	}

 	/* Get the prefix scope. A null scope means use the root scope */

 	if ((!scope_info) || (!scope_info->scope.node)) {
 		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 				  "Null scope prefix, using root node (%p)\n",
 				  acpi_gbl_root_node));

 		prefix_node = acpi_gbl_root_node;
 	} else {
 		prefix_node = scope_info->scope.node;
 		if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
 		    ACPI_DESC_TYPE_NAMED) {
 			ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
 				    prefix_node,
 				    acpi_ut_get_descriptor_name(prefix_node)));
 			return_ACPI_STATUS(AE_AML_INTERNAL);
 		}

 		if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
 			/*
 			 * This node might not be a actual "scope" node (such as a
 			 * Device/Method, etc.)  It could be a Package or other object
 			 * node. Backup up the tree to find the containing scope node.
 			 */
 			while (!acpi_ns_opens_scope(prefix_node->type) &&
 			       prefix_node->type != ACPI_TYPE_ANY) {
 				prefix_node = prefix_node->parent;
 			}
 		}
 	}

 	/* Save type. TBD: may be no longer necessary */

 	type_to_check_for = type;

 	/*
 	 * Begin examination of the actual pathname
 	 */
 	if (!pathname) {

 		/* A Null name_path is allowed and refers to the root */

 		num_segments = 0;
 		this_node = acpi_gbl_root_node;
 		path = "";

 		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 				  "Null Pathname (Zero segments), Flags=%X\n",
 				  flags));
 	} else {
 		/*
 		 * Name pointer is valid (and must be in internal name format)
 		 *
 		 * Check for scope prefixes:
 		 *
 		 * As represented in the AML stream, a namepath consists of an
 		 * optional scope prefix followed by a name segment part.
 		 *
 		 * If present, the scope prefix is either a Root Prefix (in
 		 * which case the name is fully qualified), or one or more
 		 * Parent Prefixes (in which case the name's scope is relative
 		 * to the current scope).
 		 */
 		if (*path == (u8) AML_ROOT_PREFIX) {

 			/* Pathname is fully qualified, start from the root */

 			this_node = acpi_gbl_root_node;
 			search_parent_flag = ACPI_NS_NO_UPSEARCH;

 			/* Point to name segment part */

 			path++;

 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 					  "Path is absolute from root [%p]\n",
 					  this_node));
 		} else {
 			/* Pathname is relative to current scope, start there */

 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 					  "Searching relative to prefix scope [%4.4s] (%p)\n",
 					  acpi_ut_get_node_name(prefix_node),
 					  prefix_node));

 			/*
 			 * Handle multiple Parent Prefixes (carat) by just getting
 			 * the parent node for each prefix instance.
 			 */
 			this_node = prefix_node;
 			num_carats = 0;
 			while (*path == (u8) AML_PARENT_PREFIX) {

 				/* Name is fully qualified, no search rules apply */

 				search_parent_flag = ACPI_NS_NO_UPSEARCH;

 				/*
 				 * Point past this prefix to the name segment
 				 * part or the next Parent Prefix
 				 */
 				path++;

 				/* Backup to the parent node */

 				num_carats++;
 				this_node = this_node->parent;
 				if (!this_node) {

 					/* Current scope has no parent scope */

 					ACPI_ERROR((AE_INFO,
 						    "%s: Path has too many parent prefixes (^) "
 						    "- reached beyond root node",
 						    pathname));
 					return_ACPI_STATUS(AE_NOT_FOUND);
 				}
 			}

 			if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
 				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 						  "Search scope is [%4.4s], path has %u carat(s)\n",
 						  acpi_ut_get_node_name
 						  (this_node), num_carats));
 			}
 		}

 		/*
 		 * Determine the number of ACPI name segments in this pathname.
 		 *
 		 * The segment part consists of either:
 		 *  - A Null name segment (0)
 		 *  - A dual_name_prefix followed by two 4-byte name segments
 		 *  - A multi_name_prefix followed by a byte indicating the
 		 *      number of segments and the segments themselves.
 		 *  - A single 4-byte name segment
 		 *
 		 * Examine the name prefix opcode, if any, to determine the number of
 		 * segments.
 		 */
 		switch (*path) {
 		case 0:
 			/*
 			 * Null name after a root or parent prefixes. We already
 			 * have the correct target node and there are no name segments.
 			 */
 			num_segments = 0;
 			type = this_node->type;

 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 					  "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 					  flags));
 			break;

 		case AML_DUAL_NAME_PREFIX:

 			/* More than one name_seg, search rules do not apply */

 			search_parent_flag = ACPI_NS_NO_UPSEARCH;

 			/* Two segments, point to first name segment */

 			num_segments = 2;
 			path++;

 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 					  "Dual Pathname (2 segments, Flags=%X)\n",
 					  flags));
 			break;

 		case AML_MULTI_NAME_PREFIX_OP:

 			/* More than one name_seg, search rules do not apply */

 			search_parent_flag = ACPI_NS_NO_UPSEARCH;

 			/* Extract segment count, point to first name segment */

 			path++;
 			num_segments = (u32) (u8) * path;
 			path++;

 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 					  "Multi Pathname (%u Segments, Flags=%X)\n",
 					  num_segments, flags));
 			break;

 		default:
 			/*
 			 * Not a Null name, no Dual or Multi prefix, hence there is
 			 * only one name segment and Pathname is already pointing to it.
 			 */
 			num_segments = 1;

 			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 					  "Simple Pathname (1 segment, Flags=%X)\n",
 					  flags));
 			break;
 		}

 		ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
 	}

 	/*
 	 * Search namespace for each segment of the name. Loop through and
 	 * verify (or add to the namespace) each name segment.
 	 *
 	 * The object type is significant only at the last name
 	 * segment. (We don't care about the types along the path, only
 	 * the type of the final target object.)
 	 */
 	this_search_type = ACPI_TYPE_ANY;
 	current_node = this_node;
 	while (num_segments && current_node) {
 		num_segments--;
 		if (!num_segments) {

 			/* This is the last segment, enable typechecking */

 			this_search_type = type;

 			/*
 			 * Only allow automatic parent search (search rules) if the caller
 			 * requested it AND we have a single, non-fully-qualified name_seg
 			 */
 			if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
 			    (flags & ACPI_NS_SEARCH_PARENT)) {
 				local_flags |= ACPI_NS_SEARCH_PARENT;
 			}

 			/* Set error flag according to caller */

 			if (flags & ACPI_NS_ERROR_IF_FOUND) {
 				local_flags |= ACPI_NS_ERROR_IF_FOUND;
 			}

 			/* Set override flag according to caller */

 			if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 				local_flags |= ACPI_NS_OVERRIDE_IF_FOUND;
 			}
 		}

 		/* Extract one ACPI name from the front of the pathname */

 		ACPI_MOVE_32_TO_32(&simple_name, path);

 		/* Try to find the single (4 character) ACPI name */

 		status =
 		    acpi_ns_search_and_enter(simple_name, walk_state,
 					     current_node, interpreter_mode,
 					     this_search_type, local_flags,
 					     &this_node);
 		if (ACPI_FAILURE(status)) {
 			if (status == AE_NOT_FOUND) {

 				/* Name not found in ACPI namespace */

 				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 						  "Name [%4.4s] not found in scope [%4.4s] %p\n",
 						  (char *)&simple_name,
 						  (char *)&current_node->name,
 						  current_node));
 			}

 			*return_node = this_node;
 			return_ACPI_STATUS(status);
 		}

 		/* More segments to follow? */

 		if (num_segments > 0) {
 			/*
 			 * If we have an alias to an object that opens a scope (such as a
 			 * device or processor), we need to dereference the alias here so
 			 * that we can access any children of the original node (via the
 			 * remaining segments).
 			 */
 			if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
 				if (!this_node->object) {
 					return_ACPI_STATUS(AE_NOT_EXIST);
 				}

 				if (acpi_ns_opens_scope
 				    (((struct acpi_namespace_node *)
 				      this_node->object)->type)) {
 					this_node =
 					    (struct acpi_namespace_node *)
 					    this_node->object;
 				}
 			}
 		}

 		/* Special handling for the last segment (num_segments == 0) */

 		else {
 			/*
 			 * Sanity typecheck of the target object:
 			 *
 			 * If 1) This is the last segment (num_segments == 0)
 			 *    2) And we are looking for a specific type
 			 *       (Not checking for TYPE_ANY)
 			 *    3) Which is not an alias
 			 *    4) Which is not a local type (TYPE_SCOPE)
 			 *    5) And the type of target object is known (not TYPE_ANY)
 			 *    6) And target object does not match what we are looking for
 			 *
 			 * Then we have a type mismatch. Just warn and ignore it.
 			 */
 			if ((type_to_check_for != ACPI_TYPE_ANY) &&
 			    (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
 			    (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
 			    && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
 			    && (this_node->type != ACPI_TYPE_ANY)
 			    && (this_node->type != type_to_check_for)) {

 				/* Complain about a type mismatch */

 				ACPI_WARNING((AE_INFO,
 					      "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
 					      ACPI_CAST_PTR(char, &simple_name),
 					      acpi_ut_get_type_name(this_node->
 								    type),
 					      acpi_ut_get_type_name
 					      (type_to_check_for)));
 			}

 			/*
 			 * If this is the last name segment and we are not looking for a
 			 * specific type, but the type of found object is known, use that
 			 * type to (later) see if it opens a scope.
 			 */
 			if (type == ACPI_TYPE_ANY) {
 				type = this_node->type;
 			}
 		}

 		/* Point to next name segment and make this node current */

 		path += ACPI_NAME_SIZE;
 		current_node = this_node;
 	}

 	/* Always check if we need to open a new scope */

 	if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
 		/*
 		 * If entry is a type which opens a scope, push the new scope on the
 		 * scope stack.
 		 */
 		if (acpi_ns_opens_scope(type)) {
 			status =
 			    acpi_ds_scope_stack_push(this_node, type,
 						     walk_state);
 			if (ACPI_FAILURE(status)) {
 				return_ACPI_STATUS(status);
 			}
 		}
 	}

 	*return_node = this_node;
 	return_ACPI_STATUS(AE_OK);
 }
	/*******************************************************************************
	*
	* Module Name: nsaccess - Top-level functions for accessing ACPI namespace
	*
	******************************************************************************/

	/*
	* 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 <acpi/acpi.h>
	#include "accommon.h"
	#include "amlcode.h"
	#include "acnamesp.h"
	#include "acdispat.h"

	#define _COMPONENT ACPI_NAMESPACE
	ACPI_MODULE_NAME("nsaccess")

	/*******************************************************************************
	*
	* FUNCTION: acpi_ns_root_initialize
	*
	* PARAMETERS: None
	*
	* RETURN: Status
	*
	* DESCRIPTION: Allocate and initialize the default root named objects
	*
	* MUTEX: Locks namespace for entire execution
	*
	******************************************************************************/
	acpi_status acpi_ns_root_initialize(void)
	{
	acpi_status status;
	const struct acpi_predefined_names *init_val = NULL;
	struct acpi_namespace_node *new_node;
	union acpi_operand_object *obj_desc;
	acpi_string val = NULL;

	ACPI_FUNCTION_TRACE(ns_root_initialize);

	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
	if (ACPI_FAILURE(status)) {
	return_ACPI_STATUS(status);
	}

	/*
	* The global root ptr is initially NULL, so a non-NULL value indicates
	* that acpi_ns_root_initialize() has already been called; just return.
	*/
	if (acpi_gbl_root_node) {
	status = AE_OK;
	goto unlock_and_exit;
	}

	/*
	* Tell the rest of the subsystem that the root is initialized
	* (This is OK because the namespace is locked)
	*/
	acpi_gbl_root_node = &acpi_gbl_root_node_struct;

	/* Enter the pre-defined names in the name table */

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"Entering predefined entries into namespace\n"));

	for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {

	/* _OSI is optional for now, will be permanent later */

	if (!strcmp(init_val->name, "_OSI")
	&& !acpi_gbl_create_osi_method) {
	continue;
	}

	status = acpi_ns_lookup(NULL, init_val->name, init_val->type,
	ACPI_IMODE_LOAD_PASS2,
	ACPI_NS_NO_UPSEARCH, NULL, &new_node);
	if (ACPI_FAILURE(status)) {
	ACPI_EXCEPTION((AE_INFO, status,
	"Could not create predefined name %s",
	init_val->name));
	continue;
	}

	/*
	* Name entered successfully. If entry in pre_defined_names[] specifies
	* an initial value, create the initial value.
	*/
	if (init_val->val) {
	status = acpi_os_predefined_override(init_val, &val);
	if (ACPI_FAILURE(status)) {
	ACPI_ERROR((AE_INFO,
	"Could not override predefined %s",
	init_val->name));
	}

	if (!val) {
	val = init_val->val;
	}

	/*
	* Entry requests an initial value, allocate a
	* descriptor for it.
	*/
	obj_desc =
	acpi_ut_create_internal_object(init_val->type);
	if (!obj_desc) {
	status = AE_NO_MEMORY;
	goto unlock_and_exit;
	}

	/*
	* Convert value string from table entry to
	* internal representation. Only types actually
	* used for initial values are implemented here.
	*/
	switch (init_val->type) {
	case ACPI_TYPE_METHOD:

	obj_desc->method.param_count =
	(u8) ACPI_TO_INTEGER(val);
	obj_desc->common.flags \|= AOPOBJ_DATA_VALID;

	#if defined (ACPI_ASL_COMPILER)

	/* Save the parameter count for the iASL compiler */

	new_node->value = obj_desc->method.param_count;
	#else
	/* Mark this as a very SPECIAL method */

	obj_desc->method.info_flags =
	ACPI_METHOD_INTERNAL_ONLY;
	obj_desc->method.dispatch.implementation =
	acpi_ut_osi_implementation;
	#endif
	break;

	case ACPI_TYPE_INTEGER:

	obj_desc->integer.value = ACPI_TO_INTEGER(val);
	break;

	case ACPI_TYPE_STRING:

	/* Build an object around the static string */

	obj_desc->string.length = (u32)strlen(val);
	obj_desc->string.pointer = val;
	obj_desc->common.flags \|= AOPOBJ_STATIC_POINTER;
	break;

	case ACPI_TYPE_MUTEX:

	obj_desc->mutex.node = new_node;
	obj_desc->mutex.sync_level =
	(u8) (ACPI_TO_INTEGER(val) - 1);

	/* Create a mutex */

	status =
	acpi_os_create_mutex(&obj_desc->mutex.
	os_mutex);
	if (ACPI_FAILURE(status)) {
	acpi_ut_remove_reference(obj_desc);
	goto unlock_and_exit;
	}

	/* Special case for ACPI Global Lock */

	if (strcmp(init_val->name, "_GL_") == 0) {
	acpi_gbl_global_lock_mutex = obj_desc;

	/* Create additional counting semaphore for global lock */

	status =
	acpi_os_create_semaphore(1, 0,
	&acpi_gbl_global_lock_semaphore);
	if (ACPI_FAILURE(status)) {
	acpi_ut_remove_reference
	(obj_desc);
	goto unlock_and_exit;
	}
	}
	break;

	default:

	ACPI_ERROR((AE_INFO,
	"Unsupported initial type value 0x%X",
	init_val->type));
	acpi_ut_remove_reference(obj_desc);
	obj_desc = NULL;
	continue;
	}

	/* Store pointer to value descriptor in the Node */

	status = acpi_ns_attach_object(new_node, obj_desc,
	obj_desc->common.type);

	/* Remove local reference to the object */

	acpi_ut_remove_reference(obj_desc);
	}
	}

	unlock_and_exit:
	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);

	/* Save a handle to "_GPE", it is always present */

	if (ACPI_SUCCESS(status)) {
	status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
	&acpi_gbl_fadt_gpe_device);
	}

	return_ACPI_STATUS(status);
	}

	/*******************************************************************************
	*
	* FUNCTION: acpi_ns_lookup
	*
	* PARAMETERS: scope_info - Current scope info block
	* pathname - Search pathname, in internal format
	* (as represented in the AML stream)
	* type - Type associated with name
	* interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
	* flags - Flags describing the search restrictions
	* walk_state - Current state of the walk
	* return_node - Where the Node is placed (if found
	* or created successfully)
	*
	* RETURN: Status
	*
	* DESCRIPTION: Find or enter the passed name in the name space.
	* Log an error if name not found in Exec mode.
	*
	* MUTEX: Assumes namespace is locked.
	*
	******************************************************************************/

	acpi_status
	acpi_ns_lookup(union acpi_generic_state *scope_info,
	char *pathname,
	acpi_object_type type,
	acpi_interpreter_mode interpreter_mode,
	u32 flags,
	struct acpi_walk_state *walk_state,
	struct acpi_namespace_node **return_node)
	{
	acpi_status status;
	char *path = pathname;
	struct acpi_namespace_node *prefix_node;
	struct acpi_namespace_node *current_node = NULL;
	struct acpi_namespace_node *this_node = NULL;
	u32 num_segments;
	u32 num_carats;
	acpi_name simple_name;
	acpi_object_type type_to_check_for;
	acpi_object_type this_search_type;
	u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
	u32 local_flags;

	ACPI_FUNCTION_TRACE(ns_lookup);

	if (!return_node) {
	return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	local_flags = flags &
	~(ACPI_NS_ERROR_IF_FOUND \| ACPI_NS_OVERRIDE_IF_FOUND \|
	ACPI_NS_SEARCH_PARENT);
	*return_node = ACPI_ENTRY_NOT_FOUND;
	acpi_gbl_ns_lookup_count++;

	if (!acpi_gbl_root_node) {
	return_ACPI_STATUS(AE_NO_NAMESPACE);
	}

	/* Get the prefix scope. A null scope means use the root scope */

	if ((!scope_info) \|\| (!scope_info->scope.node)) {
	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Null scope prefix, using root node (%p)\n",
	acpi_gbl_root_node));

	prefix_node = acpi_gbl_root_node;
	} else {
	prefix_node = scope_info->scope.node;
	if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
	ACPI_DESC_TYPE_NAMED) {
	ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
	prefix_node,
	acpi_ut_get_descriptor_name(prefix_node)));
	return_ACPI_STATUS(AE_AML_INTERNAL);
	}

	if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
	/*
	* This node might not be a actual "scope" node (such as a
	* Device/Method, etc.) It could be a Package or other object
	* node. Backup up the tree to find the containing scope node.
	*/
	while (!acpi_ns_opens_scope(prefix_node->type) &&
	prefix_node->type != ACPI_TYPE_ANY) {
	prefix_node = prefix_node->parent;
	}
	}
	}

	/* Save type. TBD: may be no longer necessary */

	type_to_check_for = type;

	/*
	* Begin examination of the actual pathname
	*/
	if (!pathname) {

	/* A Null name_path is allowed and refers to the root */

	num_segments = 0;
	this_node = acpi_gbl_root_node;
	path = "";

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Null Pathname (Zero segments), Flags=%X\n",
	flags));
	} else {
	/*
	* Name pointer is valid (and must be in internal name format)
	*
	* Check for scope prefixes:
	*
	* As represented in the AML stream, a namepath consists of an
	* optional scope prefix followed by a name segment part.
	*
	* If present, the scope prefix is either a Root Prefix (in
	* which case the name is fully qualified), or one or more
	* Parent Prefixes (in which case the name's scope is relative
	* to the current scope).
	*/
	if (*path == (u8) AML_ROOT_PREFIX) {

	/* Pathname is fully qualified, start from the root */

	this_node = acpi_gbl_root_node;
	search_parent_flag = ACPI_NS_NO_UPSEARCH;

	/* Point to name segment part */

	path++;

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Path is absolute from root [%p]\n",
	this_node));
	} else {
	/* Pathname is relative to current scope, start there */

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Searching relative to prefix scope [%4.4s] (%p)\n",
	acpi_ut_get_node_name(prefix_node),
	prefix_node));

	/*
	* Handle multiple Parent Prefixes (carat) by just getting
	* the parent node for each prefix instance.
	*/
	this_node = prefix_node;
	num_carats = 0;
	while (*path == (u8) AML_PARENT_PREFIX) {

	/* Name is fully qualified, no search rules apply */

	search_parent_flag = ACPI_NS_NO_UPSEARCH;

	/*
	* Point past this prefix to the name segment
	* part or the next Parent Prefix
	*/
	path++;

	/* Backup to the parent node */

	num_carats++;
	this_node = this_node->parent;
	if (!this_node) {

	/* Current scope has no parent scope */

	ACPI_ERROR((AE_INFO,
	"%s: Path has too many parent prefixes (^) "
	"- reached beyond root node",
	pathname));
	return_ACPI_STATUS(AE_NOT_FOUND);
	}
	}

	if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Search scope is [%4.4s], path has %u carat(s)\n",
	acpi_ut_get_node_name
	(this_node), num_carats));
	}
	}

	/*
	* Determine the number of ACPI name segments in this pathname.
	*
	* The segment part consists of either:
	* - A Null name segment (0)
	* - A dual_name_prefix followed by two 4-byte name segments
	* - A multi_name_prefix followed by a byte indicating the
	* number of segments and the segments themselves.
	* - A single 4-byte name segment
	*
	* Examine the name prefix opcode, if any, to determine the number of
	* segments.
	*/
	switch (*path) {
	case 0:
	/*
	* Null name after a root or parent prefixes. We already
	* have the correct target node and there are no name segments.
	*/
	num_segments = 0;
	type = this_node->type;

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Prefix-only Pathname (Zero name segments), Flags=%X\n",
	flags));
	break;

	case AML_DUAL_NAME_PREFIX:

	/* More than one name_seg, search rules do not apply */

	search_parent_flag = ACPI_NS_NO_UPSEARCH;

	/* Two segments, point to first name segment */

	num_segments = 2;
	path++;

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Dual Pathname (2 segments, Flags=%X)\n",
	flags));
	break;

	case AML_MULTI_NAME_PREFIX_OP:

	/* More than one name_seg, search rules do not apply */

	search_parent_flag = ACPI_NS_NO_UPSEARCH;

	/* Extract segment count, point to first name segment */

	path++;
	num_segments = (u32) (u8) * path;
	path++;

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Multi Pathname (%u Segments, Flags=%X)\n",
	num_segments, flags));
	break;

	default:
	/*
	* Not a Null name, no Dual or Multi prefix, hence there is
	* only one name segment and Pathname is already pointing to it.
	*/
	num_segments = 1;

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Simple Pathname (1 segment, Flags=%X)\n",
	flags));
	break;
	}

	ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
	}

	/*
	* Search namespace for each segment of the name. Loop through and
	* verify (or add to the namespace) each name segment.
	*
	* The object type is significant only at the last name
	* segment. (We don't care about the types along the path, only
	* the type of the final target object.)
	*/
	this_search_type = ACPI_TYPE_ANY;
	current_node = this_node;
	while (num_segments && current_node) {
	num_segments--;
	if (!num_segments) {

	/* This is the last segment, enable typechecking */

	this_search_type = type;

	/*
	* Only allow automatic parent search (search rules) if the caller
	* requested it AND we have a single, non-fully-qualified name_seg
	*/
	if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
	(flags & ACPI_NS_SEARCH_PARENT)) {
	local_flags \|= ACPI_NS_SEARCH_PARENT;
	}

	/* Set error flag according to caller */

	if (flags & ACPI_NS_ERROR_IF_FOUND) {
	local_flags \|= ACPI_NS_ERROR_IF_FOUND;
	}

	/* Set override flag according to caller */

	if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
	local_flags \|= ACPI_NS_OVERRIDE_IF_FOUND;
	}
	}

	/* Extract one ACPI name from the front of the pathname */

	ACPI_MOVE_32_TO_32(&simple_name, path);

	/* Try to find the single (4 character) ACPI name */

	status =
	acpi_ns_search_and_enter(simple_name, walk_state,
	current_node, interpreter_mode,
	this_search_type, local_flags,
	&this_node);
	if (ACPI_FAILURE(status)) {
	if (status == AE_NOT_FOUND) {

	/* Name not found in ACPI namespace */

	ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
	"Name [%4.4s] not found in scope [%4.4s] %p\n",
	(char *)&simple_name,
	(char *)&current_node->name,
	current_node));
	}

	*return_node = this_node;
	return_ACPI_STATUS(status);
	}

	/* More segments to follow? */

	if (num_segments > 0) {
	/*
	* If we have an alias to an object that opens a scope (such as a
	* device or processor), we need to dereference the alias here so
	* that we can access any children of the original node (via the
	* remaining segments).
	*/
	if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
	if (!this_node->object) {
	return_ACPI_STATUS(AE_NOT_EXIST);
	}

	if (acpi_ns_opens_scope
	(((struct acpi_namespace_node *)
	this_node->object)->type)) {
	this_node =
	(struct acpi_namespace_node *)
	this_node->object;
	}
	}
	}

	/* Special handling for the last segment (num_segments == 0) */

	else {
	/*
	* Sanity typecheck of the target object:
	*
	* If 1) This is the last segment (num_segments == 0)
	* 2) And we are looking for a specific type
	* (Not checking for TYPE_ANY)
	* 3) Which is not an alias
	* 4) Which is not a local type (TYPE_SCOPE)
	* 5) And the type of target object is known (not TYPE_ANY)
	* 6) And target object does not match what we are looking for
	*
	* Then we have a type mismatch. Just warn and ignore it.
	*/
	if ((type_to_check_for != ACPI_TYPE_ANY) &&
	(type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
	(type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
	&& (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
	&& (this_node->type != ACPI_TYPE_ANY)
	&& (this_node->type != type_to_check_for)) {

	/* Complain about a type mismatch */

	ACPI_WARNING((AE_INFO,
	"NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
	ACPI_CAST_PTR(char, &simple_name),
	acpi_ut_get_type_name(this_node->
	type),
	acpi_ut_get_type_name
	(type_to_check_for)));
	}

	/*
	* If this is the last name segment and we are not looking for a
	* specific type, but the type of found object is known, use that
	* type to (later) see if it opens a scope.
	*/
	if (type == ACPI_TYPE_ANY) {
	type = this_node->type;
	}
	}

	/* Point to next name segment and make this node current */

	path += ACPI_NAME_SIZE;
	current_node = this_node;
	}

	/* Always check if we need to open a new scope */

	if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
	/*
	* If entry is a type which opens a scope, push the new scope on the
	* scope stack.
	*/
	if (acpi_ns_opens_scope(type)) {
	status =
	acpi_ds_scope_stack_push(this_node, type,
	walk_state);
	if (ACPI_FAILURE(status)) {
	return_ACPI_STATUS(status);
	}
	}
	}

	*return_node = this_node;
	return_ACPI_STATUS(AE_OK);
	}