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

 *

 * Module Name: dswload - Dispatcher namespace load callbacks

 *

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

/*

 * Copyright (C) 2000 - 2018, 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 "aslcompiler.h"

#include "amlcode.h"

#include "acdispat.h"

#include "acnamesp.h"

#include "acparser.h"

#include "aslcompiler.y.h"

#define _COMPONENT          ACPI_COMPILER

        ACPI_MODULE_NAME    ("aslload")

/* Local prototypes */

static ACPI_STATUS

LdLoadFieldElements (

    ACPI_PARSE_OBJECT       *Op,

    ACPI_WALK_STATE         *WalkState);

static ACPI_STATUS

LdLoadResourceElements (

    ACPI_PARSE_OBJECT       *Op,

    ACPI_WALK_STATE         *WalkState);

static ACPI_STATUS

LdNamespace1Begin (

    ACPI_PARSE_OBJECT       *Op,

    UINT32                  Level,

    void                    *Context);

static ACPI_STATUS

LdNamespace2Begin (

    ACPI_PARSE_OBJECT       *Op,

    UINT32                  Level,

    void                    *Context);

static ACPI_STATUS

LdCommonNamespaceEnd (

    ACPI_PARSE_OBJECT       *Op,

    UINT32                  Level,

    void                    *Context);

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

 *

 * FUNCTION:    LdLoadNamespace

 *

 * PARAMETERS:  RootOp      - Root of the parse tree

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Perform a walk of the parse tree that in turn loads all of the

 *              named ASL/AML objects into the namespace. The namespace is

 *              constructed in order to resolve named references and references

 *              to named fields within resource templates/descriptors.

 *

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

ACPI_STATUS

LdLoadNamespace (

    ACPI_PARSE_OBJECT       *RootOp)

{

    ACPI_WALK_STATE         *WalkState;

    /* Create a new walk state */

    WalkState = AcpiDsCreateWalkState (0, NULL, NULL, NULL);

    if (!WalkState)

    {

        return (AE_NO_MEMORY);

    }

    /* Walk the entire parse tree, first pass */

    TrWalkParseTree (RootOp, ASL_WALK_VISIT_TWICE, LdNamespace1Begin,

        LdCommonNamespaceEnd, WalkState);

    /* Second pass to handle forward references */

    TrWalkParseTree (RootOp, ASL_WALK_VISIT_TWICE, LdNamespace2Begin,

        LdCommonNamespaceEnd, WalkState);

    /* Dump the namespace if debug is enabled */

    if (AcpiDbgLevel & ACPI_LV_TABLES)

    {

        AcpiNsDumpTables (ACPI_NS_ALL, ACPI_UINT32_MAX);

    }

    ACPI_FREE (WalkState);

    return (AE_OK);

}

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

 *

 * FUNCTION:    LdLoadFieldElements

 *

 * PARAMETERS:  Op              - Parent node (Field)

 *              WalkState       - Current walk state

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Enter the named elements of the field (children of the parent)

 *              into the namespace.

 *

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

static ACPI_STATUS

LdLoadFieldElements (

    ACPI_PARSE_OBJECT       *Op,

    ACPI_WALK_STATE         *WalkState)

{

    ACPI_PARSE_OBJECT       *Child = NULL;

    ACPI_NAMESPACE_NODE     *Node;

    ACPI_STATUS             Status;

    /* Get the first named field element */

    switch (Op->Asl.AmlOpcode)

    {

    case AML_BANK_FIELD_OP:

        Child = UtGetArg (Op, 6);

        break;

    case AML_INDEX_FIELD_OP:

        Child = UtGetArg (Op, 5);

        break;

    case AML_FIELD_OP:

        Child = UtGetArg (Op, 4);

        break;

    default:

        /* No other opcodes should arrive here */

        return (AE_BAD_PARAMETER);

    }

    /* Enter all elements into the namespace */

    while (Child)

    {

        switch (Child->Asl.AmlOpcode)

        {

        case AML_INT_RESERVEDFIELD_OP:

        case AML_INT_ACCESSFIELD_OP:

        case AML_INT_CONNECTION_OP:

            break;

        default:

            Status = AcpiNsLookup (WalkState->ScopeInfo,

                Child->Asl.Value.String,

                ACPI_TYPE_LOCAL_REGION_FIELD,

                ACPI_IMODE_LOAD_PASS1,

                ACPI_NS_NO_UPSEARCH | ACPI_NS_DONT_OPEN_SCOPE |

                    ACPI_NS_ERROR_IF_FOUND, NULL, &Node);

            if (ACPI_FAILURE (Status))

            {

                if (Status != AE_ALREADY_EXISTS)

                {

                    AslError (ASL_ERROR, ASL_MSG_CORE_EXCEPTION, Child,

                        Child->Asl.Value.String);

                    return (Status);

                }

                else if (Status == AE_ALREADY_EXISTS &&

                    (Node->Flags & ANOBJ_IS_EXTERNAL))

                {

                    Node->Type = (UINT8) ACPI_TYPE_LOCAL_REGION_FIELD;

                }

                else

                {

                    /*

                     * The name already exists in this scope

                     * But continue processing the elements

                     */

                    AslDualParseOpError (ASL_WARNING, ASL_MSG_EXTERN_COLLISION, Child,

                        Child->Asl.Value.String, ASL_MSG_EXTERN_FOUND_HERE, Node->Op,

                        Node->Op->Asl.ExternalName);

                }

            }

            else

            {

                Child->Asl.Node = Node;

                Node->Op = Child;

            }

            break;

        }

        Child = Child->Asl.Next;

    }

    return (AE_OK);

}

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

 *

 * FUNCTION:    LdLoadResourceElements

 *

 * PARAMETERS:  Op              - Parent node (Resource Descriptor)

 *              WalkState       - Current walk state

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Enter the named elements of the resource descriptor (children

 *              of the parent) into the namespace.

 *

 * NOTE: In the real AML namespace, these named elements never exist. But

 *       we simply use the namespace here as a symbol table so we can look

 *       them up as they are referenced.

 *

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

static ACPI_STATUS

LdLoadResourceElements (

    ACPI_PARSE_OBJECT       *Op,

    ACPI_WALK_STATE         *WalkState)

{

    ACPI_PARSE_OBJECT       *InitializerOp = NULL;

    ACPI_NAMESPACE_NODE     *Node;

    ACPI_STATUS             Status;

    /*

     * Enter the resource name into the namespace. Name must not already exist.

     * This opens a scope, so later field names are guaranteed to be new/unique.

     */

    Status = AcpiNsLookup (WalkState->ScopeInfo, Op->Asl.Namepath,

        ACPI_TYPE_LOCAL_RESOURCE, ACPI_IMODE_LOAD_PASS1,

        ACPI_NS_NO_UPSEARCH | ACPI_NS_ERROR_IF_FOUND,

        WalkState, &Node);

    if (ACPI_FAILURE (Status))

    {

        if (Status == AE_ALREADY_EXISTS)

        {

            /* Actual node causing the error was saved in ParentMethod */

            AslDualParseOpError (ASL_ERROR, ASL_MSG_NAME_EXISTS,

                (ACPI_PARSE_OBJECT *) Op->Asl.ParentMethod,

                Op->Asl.Namepath, ASL_MSG_FOUND_HERE, Node->Op,

                Node->Op->Asl.ExternalName);

            return (AE_OK);

        }

        return (Status);

    }

    Node->Value = (UINT32) Op->Asl.Value.Integer;

    Node->Op = Op;

    Op->Asl.Node = Node;

    /*

     * Now enter the predefined fields, for easy lookup when referenced

     * by the source ASL

     */

    InitializerOp = ASL_GET_CHILD_NODE (Op);

    while (InitializerOp)

    {

        if (InitializerOp->Asl.ExternalName)

        {

            Status = AcpiNsLookup (WalkState->ScopeInfo,

                InitializerOp->Asl.ExternalName,

                ACPI_TYPE_LOCAL_RESOURCE_FIELD,

                ACPI_IMODE_LOAD_PASS1,

                ACPI_NS_NO_UPSEARCH | ACPI_NS_DONT_OPEN_SCOPE,

                NULL, &Node);

            if (ACPI_FAILURE (Status))

            {

                return (Status);

            }

            /*

             * Store the field offset and length in the namespace node

             * so it can be used when the field is referenced

             */

            Node->Value = InitializerOp->Asl.Value.Tag.BitOffset;

            Node->Length = InitializerOp->Asl.Value.Tag.BitLength;

            InitializerOp->Asl.Node = Node;

            Node->Op = InitializerOp;

        }

        InitializerOp = ASL_GET_PEER_NODE (InitializerOp);

    }

    return (AE_OK);

}

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

 *

 * FUNCTION:    LdNamespace1Begin

 *

 * PARAMETERS:  ASL_WALK_CALLBACK

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Descending callback used during the parse tree walk. If this

 *              is a named AML opcode, enter into the namespace

 *

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

static ACPI_STATUS

LdNamespace1Begin (

    ACPI_PARSE_OBJECT       *Op,

    UINT32                  Level,

    void                    *Context)

{

    ACPI_WALK_STATE         *WalkState = (ACPI_WALK_STATE *) Context;

    ACPI_NAMESPACE_NODE     *Node;

    ACPI_PARSE_OBJECT       *MethodOp;

    ACPI_STATUS             Status;

    ACPI_OBJECT_TYPE        ObjectType;

    ACPI_OBJECT_TYPE        ActualObjectType = ACPI_TYPE_ANY;

    char                    *Path;

    UINT32                  Flags = ACPI_NS_NO_UPSEARCH;

    ACPI_PARSE_OBJECT       *Arg;

    UINT32                  i;

    BOOLEAN                 ForceNewScope = FALSE;

    const ACPI_OPCODE_INFO  *OpInfo;

    ACPI_PARSE_OBJECT       *ParentOp;

    ACPI_FUNCTION_NAME (LdNamespace1Begin);

    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Op %p [%s]\n",

        Op, Op->Asl.ParseOpName));

    /*

     * We are only interested in opcodes that have an associated name

     * (or multiple names)

     */

    switch (Op->Asl.AmlOpcode)

    {

    case AML_BANK_FIELD_OP:

    case AML_INDEX_FIELD_OP:

    case AML_FIELD_OP:

        Status = LdLoadFieldElements (Op, WalkState);

        return (Status);

    case AML_INT_CONNECTION_OP:

        if (Op->Asl.Child->Asl.AmlOpcode != AML_INT_NAMEPATH_OP)

        {

            break;

        }

        Arg = Op->Asl.Child;

        Status = AcpiNsLookup (WalkState->ScopeInfo, Arg->Asl.ExternalName,

            ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE, ACPI_NS_SEARCH_PARENT,

            WalkState, &Node);

        if (ACPI_FAILURE (Status))

        {

            break;

        }

        if (Node->Type == ACPI_TYPE_BUFFER)

        {

            Arg->Asl.Node = Node;

            Arg = Node->Op->Asl.Child;  /* Get namepath */

            Arg = Arg->Asl.Next;        /* Get actual buffer */

            Arg = Arg->Asl.Child;       /* Buffer length */

            Arg = Arg->Asl.Next;        /* RAW_DATA buffer */

        }

        break;

    default:

        /* All other opcodes go below */

        break;

    }

    /* Check if this object has already been installed in the namespace */

    if (Op->Asl.Node)

    {

        return (AE_OK);

    }

    /* Check for a possible illegal forward reference */

    if ((Op->Asl.ParseOpcode == PARSEOP_NAMESEG) ||

        (Op->Asl.ParseOpcode == PARSEOP_NAMESTRING))

    {

        /*

         * Op->Asl.Namepath will be NULL for these opcodes.

         * These opcodes are guaranteed to have a parent.

         * Examine the parent opcode.

         */

        Status = AE_OK;

        ParentOp = Op->Asl.Parent;

        OpInfo = AcpiPsGetOpcodeInfo (ParentOp->Asl.AmlOpcode);

        /*

         * Exclude all operators that actually declare a new name:

         *      Name (ABCD, 1) -> Ignore (AML_CLASS_NAMED_OBJECT)

         * We only want references to named objects:

         *      Store (2, WXYZ) -> Attempt to resolve the name

         */

        if (OpInfo->Class == AML_CLASS_NAMED_OBJECT)

        {

            return (AE_OK);

        }

        /*

         * Check if the referenced object exists at this point during

         * the load:

         * 1) If it exists, then this cannot be a forward reference.

         * 2) If it does not exist, it could be a forward reference or

         * it truly does not exist (and no external declaration).

         */

        Status = AcpiNsLookup (WalkState->ScopeInfo,

            Op->Asl.Value.Name, ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,

            ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,

            WalkState, &Node);

        if (Status == AE_NOT_FOUND)

        {

            /*

             * This is either a foward reference or the object truly

             * does not exist. The two cases can only be differentiated

             * during the cross-reference stage later. Mark the Op/Name

             * as not-found for now to indicate the need for further

             * processing.

             *

             * Special case: Allow forward references from elements of

             * Package objects. This provides compatibility with other

             * ACPI implementations. To correctly implement this, the

             * ACPICA table load defers package resolution until the entire

             * namespace has been loaded.

             */

            if ((ParentOp->Asl.ParseOpcode != PARSEOP_PACKAGE) &&

                (ParentOp->Asl.ParseOpcode != PARSEOP_VAR_PACKAGE))

            {

                Op->Asl.CompileFlags |= OP_NOT_FOUND_DURING_LOAD;

            }

            return (AE_OK);

        }

        return (Status);

    }

    Path = Op->Asl.Namepath;

    if (!Path)

    {

        return (AE_OK);

    }

    /* Map the raw opcode into an internal object type */

    switch (Op->Asl.ParseOpcode)

    {

    case PARSEOP_NAME:

        Arg = Op->Asl.Child;  /* Get the NameSeg/NameString node */

        Arg = Arg->Asl.Next;  /* First peer is the object to be associated with the name */

        /*

         * If this name refers to a ResourceTemplate, we will need to open

         * a new scope so that the resource subfield names can be entered into

         * the namespace underneath this name

         */

        if (Op->Asl.CompileFlags & OP_IS_RESOURCE_DESC)

        {

            ForceNewScope = TRUE;

        }

        /* Get the data type associated with the named object, not the name itself */

        /* Log2 loop to convert from Btype (binary) to Etype (encoded) */

        ObjectType = 1;

        for (i = 1; i < Arg->Asl.AcpiBtype; i *= 2)

        {

            ObjectType++;

        }

        break;

    case PARSEOP_EXTERNAL:

        /*

         * "External" simply enters a name and type into the namespace.

         * We must be careful to not open a new scope, however, no matter

         * what type the external name refers to (e.g., a method)

         *

         * first child is name, next child is ObjectType

         */

        ActualObjectType = (UINT8) Op->Asl.Child->Asl.Next->Asl.Value.Integer;

        ObjectType = ACPI_TYPE_ANY;

        /*

         * We will mark every new node along the path as "External". This

         * allows some or all of the nodes to be created later in the ASL

         * code. Handles cases like this:

         *

         *   External (\_SB_.PCI0.ABCD, IntObj)

         *   Scope (_SB_)

         *   {

         *       Device (PCI0)

         *       {

         *       }

         *   }

         *   Method (X)

         *   {

         *       Store (\_SB_.PCI0.ABCD, Local0)

         *   }

         */

        Flags |= ACPI_NS_EXTERNAL;

        break;

    case PARSEOP_DEFAULT_ARG:

        if (Op->Asl.CompileFlags == OP_IS_RESOURCE_DESC)

        {

            Status = LdLoadResourceElements (Op, WalkState);

            return_ACPI_STATUS (Status);

        }

        ObjectType = AslMapNamedOpcodeToDataType (Op->Asl.AmlOpcode);

        break;

    case PARSEOP_SCOPE:

        /*

         * The name referenced by Scope(Name) must already exist at this point.

         * In other words, forward references for Scope() are not supported.

         * The only real reason for this is that the MS interpreter cannot

         * handle this case. Perhaps someday this case can go away.

         */

        Status = AcpiNsLookup (WalkState->ScopeInfo, Path, ACPI_TYPE_ANY,

            ACPI_IMODE_EXECUTE, ACPI_NS_SEARCH_PARENT,

            WalkState, &(Node));

        if (ACPI_FAILURE (Status))

        {

            if (Status == AE_NOT_FOUND)

            {

                /* The name was not found, go ahead and create it */

                Status = AcpiNsLookup (WalkState->ScopeInfo, Path,

                    ACPI_TYPE_LOCAL_SCOPE,

                    ACPI_IMODE_LOAD_PASS1, Flags,

                    WalkState, &(Node));

                if (ACPI_FAILURE (Status))

                {

                    return_ACPI_STATUS (Status);

                }

                /*

                 * However, this is an error -- primarily because the MS

                 * interpreter can't handle a forward reference from the

                 * Scope() operator.

                 */

                AslError (ASL_ERROR, ASL_MSG_NOT_FOUND, Op,

                    Op->Asl.ExternalName);

                AslError (ASL_ERROR, ASL_MSG_SCOPE_FWD_REF, Op,

                    Op->Asl.ExternalName);

                goto FinishNode;

            }

            AslCoreSubsystemError (Op, Status,

                "Failure from namespace lookup", FALSE);

            return_ACPI_STATUS (Status);

        }

        else /* Status AE_OK */

        {

            /*

             * Do not allow references to external scopes from the DSDT.

             * This is because the DSDT is always loaded first, and the

             * external reference cannot be resolved -- causing a runtime

             * error because Scope() must be resolved immediately.

             * 10/2015.

             */

            if ((Node->Flags & ANOBJ_IS_EXTERNAL) &&

                (ACPI_COMPARE_NAME (Gbl_TableSignature, "DSDT")))

            {

                /* However, allowed if the reference is within a method */

                MethodOp = Op->Asl.Parent;

                while (MethodOp &&

                      (MethodOp->Asl.ParseOpcode != PARSEOP_METHOD))

                {

                    MethodOp = MethodOp->Asl.Parent;

                }

                if (!MethodOp)

                {

                    /* Not in a control method, error */

                    AslError (ASL_ERROR, ASL_MSG_CROSS_TABLE_SCOPE, Op, NULL);

                }

            }

        }

        /* We found a node with this name, now check the type */

        switch (Node->Type)

        {

        case ACPI_TYPE_LOCAL_SCOPE:

        case ACPI_TYPE_DEVICE:

        case ACPI_TYPE_POWER:

        case ACPI_TYPE_PROCESSOR:

        case ACPI_TYPE_THERMAL:

            /* These are acceptable types - they all open a new scope */

            break;

        case ACPI_TYPE_INTEGER:

        case ACPI_TYPE_STRING:

        case ACPI_TYPE_BUFFER:

            /*

             * These types we will allow, but we will change the type.

             * This enables some existing code of the form:

             *

             *  Name (DEB, 0)

             *  Scope (DEB) { ... }

             *

             * Which is used to workaround the fact that the MS interpreter

             * does not allow Scope() forward references.

             */

            sprintf (MsgBuffer, "%s [%s], changing type to [Scope]",

                Op->Asl.ExternalName, AcpiUtGetTypeName (Node->Type));

            AslError (ASL_REMARK, ASL_MSG_SCOPE_TYPE, Op, MsgBuffer);

            /* Switch the type to scope, open the new scope */

            Node->Type = ACPI_TYPE_LOCAL_SCOPE;

            Status = AcpiDsScopeStackPush (Node, ACPI_TYPE_LOCAL_SCOPE,

                WalkState);

            if (ACPI_FAILURE (Status))

            {

                return_ACPI_STATUS (Status);

            }

            break;

        default:

            /* All other types are an error */

            sprintf (MsgBuffer, "%s [%s]", Op->Asl.ExternalName,

                AcpiUtGetTypeName (Node->Type));

            AslError (ASL_ERROR, ASL_MSG_SCOPE_TYPE, Op, MsgBuffer);

            /*

             * However, switch the type to be an actual scope so

             * that compilation can continue without generating a whole

             * cascade of additional errors. Open the new scope.

             */

            Node->Type = ACPI_TYPE_LOCAL_SCOPE;

            Status = AcpiDsScopeStackPush (Node, ACPI_TYPE_LOCAL_SCOPE,

                WalkState);

            if (ACPI_FAILURE (Status))

            {

                return_ACPI_STATUS (Status);

            }

            break;

        }

        Status = AE_OK;

        goto FinishNode;

    default:

        ObjectType = AslMapNamedOpcodeToDataType (Op->Asl.AmlOpcode);

        break;

    }

    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Loading name: %s, (%s)\n",

        Op->Asl.ExternalName, AcpiUtGetTypeName (ObjectType)));

    /* The name must not already exist */

    Flags |= ACPI_NS_ERROR_IF_FOUND;

    /*

     * Enter the named type into the internal namespace. We enter the name

     * as we go downward in the parse tree. Any necessary subobjects that

     * involve arguments to the opcode must be created as we go back up the

     * parse tree later.

     */

    Status = AcpiNsLookup (WalkState->ScopeInfo, Path, ObjectType,

        ACPI_IMODE_LOAD_PASS1, Flags, WalkState, &Node);

    if (ACPI_FAILURE (Status))

    {

        if (Status == AE_ALREADY_EXISTS)

        {

            /* The name already exists in this scope */

            if (Node->Type == ACPI_TYPE_LOCAL_SCOPE)

            {

                /* Allow multiple references to the same scope */

                Node->Type = (UINT8) ObjectType;

                Status = AE_OK;

            }

            else if ((Node->Flags & ANOBJ_IS_EXTERNAL) &&

                     (Op->Asl.ParseOpcode != PARSEOP_EXTERNAL))

            {

                /*

                 * Allow one create on an object or segment that was

                 * previously declared External

                 */

                Node->Flags &= ~ANOBJ_IS_EXTERNAL;

                Node->Type = (UINT8) ObjectType;

                /* Just retyped a node, probably will need to open a scope */

                if (AcpiNsOpensScope (ObjectType))

                {

                    Status = AcpiDsScopeStackPush (Node, ObjectType, WalkState);

                    if (ACPI_FAILURE (Status))

                    {

                        return_ACPI_STATUS (Status);

                    }

                }

                Status = AE_OK;

            }

            else if (!(Node->Flags & ANOBJ_IS_EXTERNAL) &&

                     (Op->Asl.ParseOpcode == PARSEOP_EXTERNAL))

            {

                /*

                 * Allow externals in same scope as the definition of the

                 * actual object. Similar to C. Allows multiple definition

                 * blocks that refer to each other in the same file.

                 */

                Status = AE_OK;

            }

            else if ((Node->Flags & ANOBJ_IS_EXTERNAL) &&

                     (Op->Asl.ParseOpcode == PARSEOP_EXTERNAL) &&

                     (ObjectType == ACPI_TYPE_ANY))

            {

                /* Allow update of externals of unknown type. */

                if (AcpiNsOpensScope (ActualObjectType))

                {

                    Node->Type = (UINT8) ActualObjectType;

                    Status = AE_OK;

                }

                else

                {

                    sprintf (MsgBuffer, "%s [%s]", Op->Asl.ExternalName,

                        AcpiUtGetTypeName (Node->Type));

                    AslError (ASL_ERROR, ASL_MSG_SCOPE_TYPE, Op, MsgBuffer);

                    return_ACPI_STATUS (AE_OK);

                }

            }

            else

            {

                /* Valid error, object already exists */

                AslDualParseOpError (ASL_ERROR, ASL_MSG_NAME_EXISTS, Op,

                    Op->Asl.ExternalName, ASL_MSG_FOUND_HERE, Node->Op,

                    Node->Op->Asl.ExternalName);

                return_ACPI_STATUS (AE_OK);

            }

        }

        else

        {

            AslCoreSubsystemError (Op, Status,

                "Failure from namespace lookup", FALSE);

            return_ACPI_STATUS (Status);

        }

    }

    if (ForceNewScope)

    {

        Status = AcpiDsScopeStackPush (Node, ObjectType, WalkState);

        if (ACPI_FAILURE (Status))

        {

            return_ACPI_STATUS (Status);

        }

    }

FinishNode:

    /*

     * Point the parse node to the new namespace node, and point

     * the Node back to the original Parse node

     */

    Op->Asl.Node = Node;

    Node->Op = Op;

    /* Set the actual data type if appropriate (EXTERNAL term only) */

    if (ActualObjectType != ACPI_TYPE_ANY)

    {

        Node->Type = (UINT8) ActualObjectType;

        Node->Value = ASL_EXTERNAL_METHOD;

    }

    if (Op->Asl.ParseOpcode == PARSEOP_METHOD)

    {

        /*

         * Get the method argument count from "Extra" and save

         * it in the namespace node

         */

        Node->Value = (UINT32) Op->Asl.Extra;

    }

    return_ACPI_STATUS (Status);

}

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

 *

 * FUNCTION:    LdNamespace2Begin

 *

 * PARAMETERS:  ASL_WALK_CALLBACK

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Descending callback used during the pass 2 parse tree walk.

 *              Second pass resolves some forward references.

 *

 * Notes:

 * Currently only needs to handle the Alias operator.

 * Could be used to allow forward references from the Scope() operator, but

 * the MS interpreter does not allow this, so this compiler does not either.

 *

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

static ACPI_STATUS

LdNamespace2Begin (

    ACPI_PARSE_OBJECT       *Op,

    UINT32                  Level,

    void                    *Context)

{

    ACPI_WALK_STATE         *WalkState = (ACPI_WALK_STATE *) Context;