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      1 /******************************************************************************
      2  *
      3  * Module Name: exresolv - AML Interpreter object resolution
      4  *
      5  *****************************************************************************/
      6 
      7 /******************************************************************************
      8  *
      9  * 1. Copyright Notice
     10  *
     11  * Some or all of this work - Copyright (c) 1999 - 2025, Intel Corp.
     12  * All rights reserved.
     13  *
     14  * 2. License
     15  *
     16  * 2.1. This is your license from Intel Corp. under its intellectual property
     17  * rights. You may have additional license terms from the party that provided
     18  * you this software, covering your right to use that party's intellectual
     19  * property rights.
     20  *
     21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
     22  * copy of the source code appearing in this file ("Covered Code") an
     23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
     24  * base code distributed originally by Intel ("Original Intel Code") to copy,
     25  * make derivatives, distribute, use and display any portion of the Covered
     26  * Code in any form, with the right to sublicense such rights; and
     27  *
     28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
     29  * license (with the right to sublicense), under only those claims of Intel
     30  * patents that are infringed by the Original Intel Code, to make, use, sell,
     31  * offer to sell, and import the Covered Code and derivative works thereof
     32  * solely to the minimum extent necessary to exercise the above copyright
     33  * license, and in no event shall the patent license extend to any additions
     34  * to or modifications of the Original Intel Code. No other license or right
     35  * is granted directly or by implication, estoppel or otherwise;
     36  *
     37  * The above copyright and patent license is granted only if the following
     38  * conditions are met:
     39  *
     40  * 3. Conditions
     41  *
     42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
     43  * Redistribution of source code of any substantial portion of the Covered
     44  * Code or modification with rights to further distribute source must include
     45  * the above Copyright Notice, the above License, this list of Conditions,
     46  * and the following Disclaimer and Export Compliance provision. In addition,
     47  * Licensee must cause all Covered Code to which Licensee contributes to
     48  * contain a file documenting the changes Licensee made to create that Covered
     49  * Code and the date of any change. Licensee must include in that file the
     50  * documentation of any changes made by any predecessor Licensee. Licensee
     51  * must include a prominent statement that the modification is derived,
     52  * directly or indirectly, from Original Intel Code.
     53  *
     54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
     55  * Redistribution of source code of any substantial portion of the Covered
     56  * Code or modification without rights to further distribute source must
     57  * include the following Disclaimer and Export Compliance provision in the
     58  * documentation and/or other materials provided with distribution. In
     59  * addition, Licensee may not authorize further sublicense of source of any
     60  * portion of the Covered Code, and must include terms to the effect that the
     61  * license from Licensee to its licensee is limited to the intellectual
     62  * property embodied in the software Licensee provides to its licensee, and
     63  * not to intellectual property embodied in modifications its licensee may
     64  * make.
     65  *
     66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
     67  * substantial portion of the Covered Code or modification must reproduce the
     68  * above Copyright Notice, and the following Disclaimer and Export Compliance
     69  * provision in the documentation and/or other materials provided with the
     70  * distribution.
     71  *
     72  * 3.4. Intel retains all right, title, and interest in and to the Original
     73  * Intel Code.
     74  *
     75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
     76  * Intel shall be used in advertising or otherwise to promote the sale, use or
     77  * other dealings in products derived from or relating to the Covered Code
     78  * without prior written authorization from Intel.
     79  *
     80  * 4. Disclaimer and Export Compliance
     81  *
     82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
     83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
     84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
     85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
     86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
     87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
     88  * PARTICULAR PURPOSE.
     89  *
     90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
     91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
     92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
     93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
     94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
     95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
     96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
     97  * LIMITED REMEDY.
     98  *
     99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
    100  * software or system incorporating such software without first obtaining any
    101  * required license or other approval from the U. S. Department of Commerce or
    102  * any other agency or department of the United States Government. In the
    103  * event Licensee exports any such software from the United States or
    104  * re-exports any such software from a foreign destination, Licensee shall
    105  * ensure that the distribution and export/re-export of the software is in
    106  * compliance with all laws, regulations, orders, or other restrictions of the
    107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
    108  * any of its subsidiaries will export/re-export any technical data, process,
    109  * software, or service, directly or indirectly, to any country for which the
    110  * United States government or any agency thereof requires an export license,
    111  * other governmental approval, or letter of assurance, without first obtaining
    112  * such license, approval or letter.
    113  *
    114  *****************************************************************************
    115  *
    116  * Alternatively, you may choose to be licensed under the terms of the
    117  * following license:
    118  *
    119  * Redistribution and use in source and binary forms, with or without
    120  * modification, are permitted provided that the following conditions
    121  * are met:
    122  * 1. Redistributions of source code must retain the above copyright
    123  *    notice, this list of conditions, and the following disclaimer,
    124  *    without modification.
    125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
    126  *    substantially similar to the "NO WARRANTY" disclaimer below
    127  *    ("Disclaimer") and any redistribution must be conditioned upon
    128  *    including a substantially similar Disclaimer requirement for further
    129  *    binary redistribution.
    130  * 3. Neither the names of the above-listed copyright holders nor the names
    131  *    of any contributors may be used to endorse or promote products derived
    132  *    from this software without specific prior written permission.
    133  *
    134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    145  *
    146  * Alternatively, you may choose to be licensed under the terms of the
    147  * GNU General Public License ("GPL") version 2 as published by the Free
    148  * Software Foundation.
    149  *
    150  *****************************************************************************/
    151 
    152 #include "acpi.h"
    153 #include "accommon.h"
    154 #include "amlcode.h"
    155 #include "acdispat.h"
    156 #include "acinterp.h"
    157 #include "acnamesp.h"
    158 
    159 
    160 #define _COMPONENT          ACPI_EXECUTER
    161         ACPI_MODULE_NAME    ("exresolv")
    162 
    163 /* Local prototypes */
    164 
    165 static ACPI_STATUS
    166 AcpiExResolveObjectToValue (
    167     ACPI_OPERAND_OBJECT     **StackPtr,
    168     ACPI_WALK_STATE         *WalkState);
    169 
    170 
    171 /*******************************************************************************
    172  *
    173  * FUNCTION:    AcpiExResolveToValue
    174  *
    175  * PARAMETERS:  **StackPtr          - Points to entry on ObjStack, which can
    176  *                                    be either an (ACPI_OPERAND_OBJECT *)
    177  *                                    or an ACPI_HANDLE.
    178  *              WalkState           - Current method state
    179  *
    180  * RETURN:      Status
    181  *
    182  * DESCRIPTION: Convert Reference objects to values
    183  *
    184  ******************************************************************************/
    185 
    186 ACPI_STATUS
    187 AcpiExResolveToValue (
    188     ACPI_OPERAND_OBJECT     **StackPtr,
    189     ACPI_WALK_STATE         *WalkState)
    190 {
    191     ACPI_STATUS             Status;
    192 
    193 
    194     ACPI_FUNCTION_TRACE_PTR (ExResolveToValue, StackPtr);
    195 
    196 
    197     if (!StackPtr || !*StackPtr)
    198     {
    199         ACPI_ERROR ((AE_INFO, "Internal - null pointer"));
    200         return_ACPI_STATUS (AE_AML_NO_OPERAND);
    201     }
    202 
    203     /*
    204      * The entity pointed to by the StackPtr can be either
    205      * 1) A valid ACPI_OPERAND_OBJECT, or
    206      * 2) A ACPI_NAMESPACE_NODE (NamedObj)
    207      */
    208     if (ACPI_GET_DESCRIPTOR_TYPE (*StackPtr) == ACPI_DESC_TYPE_OPERAND)
    209     {
    210         Status = AcpiExResolveObjectToValue (StackPtr, WalkState);
    211         if (ACPI_FAILURE (Status))
    212         {
    213             return_ACPI_STATUS (Status);
    214         }
    215 
    216         if (!*StackPtr)
    217         {
    218             ACPI_ERROR ((AE_INFO, "Internal - null pointer"));
    219             return_ACPI_STATUS (AE_AML_NO_OPERAND);
    220         }
    221     }
    222 
    223     /*
    224      * Object on the stack may have changed if AcpiExResolveObjectToValue()
    225      * was called (i.e., we can't use an _else_ here.)
    226      */
    227     if (ACPI_GET_DESCRIPTOR_TYPE (*StackPtr) == ACPI_DESC_TYPE_NAMED)
    228     {
    229         Status = AcpiExResolveNodeToValue (
    230             ACPI_CAST_INDIRECT_PTR (ACPI_NAMESPACE_NODE, StackPtr),
    231             WalkState);
    232         if (ACPI_FAILURE (Status))
    233         {
    234             return_ACPI_STATUS (Status);
    235         }
    236     }
    237 
    238     ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Resolved object %p\n", *StackPtr));
    239     return_ACPI_STATUS (AE_OK);
    240 }
    241 
    242 
    243 /*******************************************************************************
    244  *
    245  * FUNCTION:    AcpiExResolveObjectToValue
    246  *
    247  * PARAMETERS:  StackPtr        - Pointer to an internal object
    248  *              WalkState       - Current method state
    249  *
    250  * RETURN:      Status
    251  *
    252  * DESCRIPTION: Retrieve the value from an internal object. The Reference type
    253  *              uses the associated AML opcode to determine the value.
    254  *
    255  ******************************************************************************/
    256 
    257 static ACPI_STATUS
    258 AcpiExResolveObjectToValue (
    259     ACPI_OPERAND_OBJECT     **StackPtr,
    260     ACPI_WALK_STATE         *WalkState)
    261 {
    262     ACPI_STATUS             Status = AE_OK;
    263     ACPI_OPERAND_OBJECT     *StackDesc;
    264     ACPI_OPERAND_OBJECT     *ObjDesc = NULL;
    265     UINT8                   RefType;
    266 
    267 
    268     ACPI_FUNCTION_TRACE (ExResolveObjectToValue);
    269 
    270 
    271     StackDesc = *StackPtr;
    272 
    273     /* This is an object of type ACPI_OPERAND_OBJECT */
    274 
    275     switch (StackDesc->Common.Type)
    276     {
    277     case ACPI_TYPE_LOCAL_REFERENCE:
    278 
    279         RefType = StackDesc->Reference.Class;
    280 
    281         switch (RefType)
    282         {
    283         case ACPI_REFCLASS_LOCAL:
    284         case ACPI_REFCLASS_ARG:
    285             /*
    286              * Get the local from the method's state info
    287              * Note: this increments the local's object reference count
    288              */
    289             Status = AcpiDsMethodDataGetValue (RefType,
    290                 StackDesc->Reference.Value, WalkState, &ObjDesc);
    291             if (ACPI_FAILURE (Status))
    292             {
    293                 return_ACPI_STATUS (Status);
    294             }
    295 
    296             ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "[Arg/Local %X] ValueObj is %p\n",
    297                 StackDesc->Reference.Value, ObjDesc));
    298 
    299             /*
    300              * Now we can delete the original Reference Object and
    301              * replace it with the resolved value
    302              */
    303             AcpiUtRemoveReference (StackDesc);
    304             *StackPtr = ObjDesc;
    305             break;
    306 
    307         case ACPI_REFCLASS_INDEX:
    308 
    309             switch (StackDesc->Reference.TargetType)
    310             {
    311             case ACPI_TYPE_BUFFER_FIELD:
    312 
    313                 /* Just return - do not dereference */
    314                 break;
    315 
    316             case ACPI_TYPE_PACKAGE:
    317 
    318                 /* If method call or CopyObject - do not dereference */
    319 
    320                 if ((WalkState->Opcode == AML_INT_METHODCALL_OP) ||
    321                     (WalkState->Opcode == AML_COPY_OBJECT_OP))
    322                 {
    323                     break;
    324                 }
    325 
    326                 /* Otherwise, dereference the PackageIndex to a package element */
    327 
    328                 ObjDesc = *StackDesc->Reference.Where;
    329                 if (ObjDesc)
    330                 {
    331                     /*
    332                      * Valid object descriptor, copy pointer to return value
    333                      * (i.e., dereference the package index)
    334                      * Delete the ref object, increment the returned object
    335                      */
    336                     AcpiUtAddReference (ObjDesc);
    337                     *StackPtr = ObjDesc;
    338                 }
    339                 else
    340                 {
    341                     /*
    342                      * A NULL object descriptor means an uninitialized element of
    343                      * the package, can't dereference it
    344                      */
    345                     ACPI_ERROR ((AE_INFO,
    346                         "Attempt to dereference an Index to "
    347                         "NULL package element Idx=%p",
    348                         StackDesc));
    349                     Status = AE_AML_UNINITIALIZED_ELEMENT;
    350                 }
    351                 break;
    352 
    353             default:
    354 
    355                 /* Invalid reference object */
    356 
    357                 ACPI_ERROR ((AE_INFO,
    358                     "Unknown TargetType 0x%X in Index/Reference object %p",
    359                     StackDesc->Reference.TargetType, StackDesc));
    360                 Status = AE_AML_INTERNAL;
    361                 break;
    362             }
    363             break;
    364 
    365         case ACPI_REFCLASS_REFOF:
    366         case ACPI_REFCLASS_DEBUG:
    367         case ACPI_REFCLASS_TABLE:
    368 
    369             /* Just leave the object as-is, do not dereference */
    370 
    371             break;
    372 
    373         case ACPI_REFCLASS_NAME:   /* Reference to a named object */
    374 
    375             /* Dereference the name */
    376 
    377             if ((StackDesc->Reference.Node->Type == ACPI_TYPE_DEVICE) ||
    378                 (StackDesc->Reference.Node->Type == ACPI_TYPE_THERMAL))
    379             {
    380                 /* These node types do not have 'real' subobjects */
    381 
    382                 *StackPtr = (void *) StackDesc->Reference.Node;
    383             }
    384             else
    385             {
    386                 /* Get the object pointed to by the namespace node */
    387 
    388                 *StackPtr = (StackDesc->Reference.Node)->Object;
    389                 AcpiUtAddReference (*StackPtr);
    390             }
    391 
    392             AcpiUtRemoveReference (StackDesc);
    393             break;
    394 
    395         default:
    396 
    397             ACPI_ERROR ((AE_INFO,
    398                 "Unknown Reference type 0x%X in %p",
    399                 RefType, StackDesc));
    400             Status = AE_AML_INTERNAL;
    401             break;
    402         }
    403         break;
    404 
    405     case ACPI_TYPE_BUFFER:
    406 
    407         Status = AcpiDsGetBufferArguments (StackDesc);
    408         break;
    409 
    410     case ACPI_TYPE_PACKAGE:
    411 
    412         Status = AcpiDsGetPackageArguments (StackDesc);
    413         break;
    414 
    415     case ACPI_TYPE_BUFFER_FIELD:
    416     case ACPI_TYPE_LOCAL_REGION_FIELD:
    417     case ACPI_TYPE_LOCAL_BANK_FIELD:
    418     case ACPI_TYPE_LOCAL_INDEX_FIELD:
    419 
    420         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
    421             "FieldRead SourceDesc=%p Type=%X\n",
    422             StackDesc, StackDesc->Common.Type));
    423 
    424         Status = AcpiExReadDataFromField (WalkState, StackDesc, &ObjDesc);
    425 
    426         /* Remove a reference to the original operand, then override */
    427 
    428         AcpiUtRemoveReference (*StackPtr);
    429         *StackPtr = (void *) ObjDesc;
    430         break;
    431 
    432     default:
    433 
    434         break;
    435     }
    436 
    437     return_ACPI_STATUS (Status);
    438 }
    439 
    440 
    441 /*******************************************************************************
    442  *
    443  * FUNCTION:    AcpiExResolveMultiple
    444  *
    445  * PARAMETERS:  WalkState           - Current state (contains AML opcode)
    446  *              Operand             - Starting point for resolution
    447  *              ReturnType          - Where the object type is returned
    448  *              ReturnDesc          - Where the resolved object is returned
    449  *
    450  * RETURN:      Status
    451  *
    452  * DESCRIPTION: Return the base object and type. Traverse a reference list if
    453  *              necessary to get to the base object.
    454  *
    455  ******************************************************************************/
    456 
    457 ACPI_STATUS
    458 AcpiExResolveMultiple (
    459     ACPI_WALK_STATE         *WalkState,
    460     ACPI_OPERAND_OBJECT     *Operand,
    461     ACPI_OBJECT_TYPE        *ReturnType,
    462     ACPI_OPERAND_OBJECT     **ReturnDesc)
    463 {
    464     ACPI_OPERAND_OBJECT     *ObjDesc = ACPI_CAST_PTR (void, Operand);
    465     ACPI_NAMESPACE_NODE     *Node = ACPI_CAST_PTR (ACPI_NAMESPACE_NODE, Operand);
    466     ACPI_OBJECT_TYPE        Type;
    467     ACPI_STATUS             Status;
    468 
    469 
    470     ACPI_FUNCTION_TRACE (AcpiExResolveMultiple);
    471 
    472 
    473     /* Operand can be either a namespace node or an operand descriptor */
    474 
    475     switch (ACPI_GET_DESCRIPTOR_TYPE (ObjDesc))
    476     {
    477     case ACPI_DESC_TYPE_OPERAND:
    478 
    479         Type = ObjDesc->Common.Type;
    480         break;
    481 
    482     case ACPI_DESC_TYPE_NAMED:
    483 
    484         Type = ((ACPI_NAMESPACE_NODE *) ObjDesc)->Type;
    485         ObjDesc = AcpiNsGetAttachedObject (Node);
    486 
    487         /* If we had an Alias node, use the attached object for type info */
    488 
    489         if (Type == ACPI_TYPE_LOCAL_ALIAS)
    490         {
    491             Type = ((ACPI_NAMESPACE_NODE *) ObjDesc)->Type;
    492             ObjDesc = AcpiNsGetAttachedObject (
    493                 (ACPI_NAMESPACE_NODE *) ObjDesc);
    494         }
    495 
    496         switch (Type)
    497         {
    498         case ACPI_TYPE_DEVICE:
    499         case ACPI_TYPE_THERMAL:
    500 
    501             /* These types have no attached subobject */
    502             break;
    503 
    504         default:
    505 
    506             /* All other types require a subobject */
    507 
    508             if (!ObjDesc)
    509             {
    510                 ACPI_ERROR ((AE_INFO,
    511                     "[%4.4s] Node is unresolved or uninitialized",
    512                     AcpiUtGetNodeName (Node)));
    513                 return_ACPI_STATUS (AE_AML_UNINITIALIZED_NODE);
    514             }
    515             break;
    516         }
    517         break;
    518 
    519     default:
    520         return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
    521     }
    522 
    523     /* If type is anything other than a reference, we are done */
    524 
    525     if (Type != ACPI_TYPE_LOCAL_REFERENCE)
    526     {
    527         goto Exit;
    528     }
    529 
    530     /*
    531      * For reference objects created via the RefOf, Index, or Load/LoadTable
    532      * operators, we need to get to the base object (as per the ACPI
    533      * specification of the ObjectType and SizeOf operators). This means
    534      * traversing the list of possibly many nested references.
    535      */
    536     while (ObjDesc->Common.Type == ACPI_TYPE_LOCAL_REFERENCE)
    537     {
    538         switch (ObjDesc->Reference.Class)
    539         {
    540         case ACPI_REFCLASS_REFOF:
    541         case ACPI_REFCLASS_NAME:
    542 
    543             /* Dereference the reference pointer */
    544 
    545             if (ObjDesc->Reference.Class == ACPI_REFCLASS_REFOF)
    546             {
    547                 Node = ObjDesc->Reference.Object;
    548             }
    549             else /* AML_INT_NAMEPATH_OP */
    550             {
    551                 Node = ObjDesc->Reference.Node;
    552             }
    553 
    554             /* All "References" point to a NS node */
    555 
    556             if (ACPI_GET_DESCRIPTOR_TYPE (Node) != ACPI_DESC_TYPE_NAMED)
    557             {
    558                 ACPI_ERROR ((AE_INFO,
    559                     "Not a namespace node %p [%s]",
    560                     Node, AcpiUtGetDescriptorName (Node)));
    561                 return_ACPI_STATUS (AE_AML_INTERNAL);
    562             }
    563 
    564             /* Get the attached object */
    565 
    566             ObjDesc = AcpiNsGetAttachedObject (Node);
    567             if (!ObjDesc)
    568             {
    569                 /* No object, use the NS node type */
    570 
    571                 Type = AcpiNsGetType (Node);
    572                 goto Exit;
    573             }
    574 
    575             /* Check for circular references */
    576 
    577             if (ObjDesc == Operand)
    578             {
    579                 return_ACPI_STATUS (AE_AML_CIRCULAR_REFERENCE);
    580             }
    581             break;
    582 
    583         case ACPI_REFCLASS_INDEX:
    584 
    585             /* Get the type of this reference (index into another object) */
    586 
    587             Type = ObjDesc->Reference.TargetType;
    588             if (Type != ACPI_TYPE_PACKAGE)
    589             {
    590                 goto Exit;
    591             }
    592 
    593             /*
    594              * The main object is a package, we want to get the type
    595              * of the individual package element that is referenced by
    596              * the index.
    597              *
    598              * This could of course in turn be another reference object.
    599              */
    600             ObjDesc = *(ObjDesc->Reference.Where);
    601             if (!ObjDesc)
    602             {
    603                 /* NULL package elements are allowed */
    604 
    605                 Type = 0; /* Uninitialized */
    606                 goto Exit;
    607             }
    608             break;
    609 
    610         case ACPI_REFCLASS_TABLE:
    611 
    612             Type = ACPI_TYPE_DDB_HANDLE;
    613             goto Exit;
    614 
    615         case ACPI_REFCLASS_LOCAL:
    616         case ACPI_REFCLASS_ARG:
    617 
    618             if (ReturnDesc)
    619             {
    620                 Status = AcpiDsMethodDataGetValue (ObjDesc->Reference.Class,
    621                     ObjDesc->Reference.Value, WalkState, &ObjDesc);
    622                 if (ACPI_FAILURE (Status))
    623                 {
    624                     return_ACPI_STATUS (Status);
    625                 }
    626                 AcpiUtRemoveReference (ObjDesc);
    627             }
    628             else
    629             {
    630                 Status = AcpiDsMethodDataGetNode (ObjDesc->Reference.Class,
    631                     ObjDesc->Reference.Value, WalkState, &Node);
    632                 if (ACPI_FAILURE (Status))
    633                 {
    634                     return_ACPI_STATUS (Status);
    635                 }
    636 
    637                 ObjDesc = AcpiNsGetAttachedObject (Node);
    638                 if (!ObjDesc)
    639                 {
    640                     Type = ACPI_TYPE_ANY;
    641                     goto Exit;
    642                 }
    643             }
    644             break;
    645 
    646         case ACPI_REFCLASS_DEBUG:
    647 
    648             /* The Debug Object is of type "DebugObject" */
    649 
    650             Type = ACPI_TYPE_DEBUG_OBJECT;
    651             goto Exit;
    652 
    653         default:
    654 
    655             ACPI_ERROR ((AE_INFO,
    656                 "Unknown Reference Class 0x%2.2X",
    657                 ObjDesc->Reference.Class));
    658             return_ACPI_STATUS (AE_AML_INTERNAL);
    659         }
    660     }
    661 
    662     /*
    663      * Now we are guaranteed to have an object that has not been created
    664      * via the RefOf or Index operators.
    665      */
    666     Type = ObjDesc->Common.Type;
    667 
    668 
    669 Exit:
    670     /* Convert internal types to external types */
    671 
    672     switch (Type)
    673     {
    674     case ACPI_TYPE_LOCAL_REGION_FIELD:
    675     case ACPI_TYPE_LOCAL_BANK_FIELD:
    676     case ACPI_TYPE_LOCAL_INDEX_FIELD:
    677 
    678         Type = ACPI_TYPE_FIELD_UNIT;
    679         break;
    680 
    681     case ACPI_TYPE_LOCAL_SCOPE:
    682 
    683         /* Per ACPI Specification, Scope is untyped */
    684 
    685         Type = ACPI_TYPE_ANY;
    686         break;
    687 
    688     default:
    689 
    690         /* No change to Type required */
    691 
    692         break;
    693     }
    694 
    695     *ReturnType = Type;
    696     if (ReturnDesc)
    697     {
    698         *ReturnDesc = ObjDesc;
    699     }
    700     return_ACPI_STATUS (AE_OK);
    701 }
    702