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nsaccess.c revision 1.17
      1 /*******************************************************************************
      2  *
      3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
      4  *
      5  ******************************************************************************/
      6 
      7 /*
      8  * Copyright (C) 2000 - 2019, Intel Corp.
      9  * All rights reserved.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions, and the following disclaimer,
     16  *    without modification.
     17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
     18  *    substantially similar to the "NO WARRANTY" disclaimer below
     19  *    ("Disclaimer") and any redistribution must be conditioned upon
     20  *    including a substantially similar Disclaimer requirement for further
     21  *    binary redistribution.
     22  * 3. Neither the names of the above-listed copyright holders nor the names
     23  *    of any contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * Alternatively, this software may be distributed under the terms of the
     27  * GNU General Public License ("GPL") version 2 as published by the Free
     28  * Software Foundation.
     29  *
     30  * NO WARRANTY
     31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
     34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     41  * POSSIBILITY OF SUCH DAMAGES.
     42  */
     43 
     44 #include "acpi.h"
     45 #include "accommon.h"
     46 #include "amlcode.h"
     47 #include "acnamesp.h"
     48 #include "acdispat.h"
     49 
     50 #ifdef ACPI_ASL_COMPILER
     51     #include "acdisasm.h"
     52 #endif
     53 
     54 #define _COMPONENT          ACPI_NAMESPACE
     55         ACPI_MODULE_NAME    ("nsaccess")
     56 
     57 
     58 /*******************************************************************************
     59  *
     60  * FUNCTION:    AcpiNsRootInitialize
     61  *
     62  * PARAMETERS:  None
     63  *
     64  * RETURN:      Status
     65  *
     66  * DESCRIPTION: Allocate and initialize the default root named objects
     67  *
     68  * MUTEX:       Locks namespace for entire execution
     69  *
     70  ******************************************************************************/
     71 
     72 ACPI_STATUS
     73 AcpiNsRootInitialize (
     74     void)
     75 {
     76     ACPI_STATUS                 Status;
     77     const ACPI_PREDEFINED_NAMES *InitVal = NULL;
     78     ACPI_NAMESPACE_NODE         *NewNode;
     79     ACPI_OPERAND_OBJECT         *ObjDesc;
     80     ACPI_STRING                 Val = NULL;
     81 
     82 
     83     ACPI_FUNCTION_TRACE (NsRootInitialize);
     84 
     85 
     86     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
     87     if (ACPI_FAILURE (Status))
     88     {
     89         return_ACPI_STATUS (Status);
     90     }
     91 
     92     /*
     93      * The global root ptr is initially NULL, so a non-NULL value indicates
     94      * that AcpiNsRootInitialize() has already been called; just return.
     95      */
     96     if (AcpiGbl_RootNode)
     97     {
     98         Status = AE_OK;
     99         goto UnlockAndExit;
    100     }
    101 
    102     /*
    103      * Tell the rest of the subsystem that the root is initialized
    104      * (This is OK because the namespace is locked)
    105      */
    106     AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
    107 
    108     /* Enter the pre-defined names in the name table */
    109 
    110     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
    111         "Entering predefined entries into namespace\n"));
    112 
    113     for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
    114     {
    115         /* _OSI is optional for now, will be permanent later */
    116 
    117         if (!strcmp (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
    118         {
    119             continue;
    120         }
    121 
    122         Status = AcpiNsLookup (NULL, ACPI_CAST_PTR (char, InitVal->Name),
    123             InitVal->Type, ACPI_IMODE_LOAD_PASS2, ACPI_NS_NO_UPSEARCH,
    124             NULL, &NewNode);
    125         if (ACPI_FAILURE (Status))
    126         {
    127             ACPI_EXCEPTION ((AE_INFO, Status,
    128                 "Could not create predefined name %s",
    129                 InitVal->Name));
    130             continue;
    131         }
    132 
    133         /*
    134          * Name entered successfully. If entry in PreDefinedNames[] specifies
    135          * an initial value, create the initial value.
    136          */
    137         if (InitVal->Val)
    138         {
    139             Status = AcpiOsPredefinedOverride (InitVal, &Val);
    140             if (ACPI_FAILURE (Status))
    141             {
    142                 ACPI_ERROR ((AE_INFO,
    143                     "Could not override predefined %s",
    144                     InitVal->Name));
    145             }
    146 
    147             if (!Val)
    148             {
    149                 Val = __UNCONST(InitVal->Val);
    150             }
    151 
    152             /*
    153              * Entry requests an initial value, allocate a
    154              * descriptor for it.
    155              */
    156             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
    157             if (!ObjDesc)
    158             {
    159                 Status = AE_NO_MEMORY;
    160                 goto UnlockAndExit;
    161             }
    162 
    163             /*
    164              * Convert value string from table entry to
    165              * internal representation. Only types actually
    166              * used for initial values are implemented here.
    167              */
    168             switch (InitVal->Type)
    169             {
    170             case ACPI_TYPE_METHOD:
    171 
    172                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
    173                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
    174 
    175 #if defined (ACPI_ASL_COMPILER)
    176 
    177                 /* Save the parameter count for the iASL compiler */
    178 
    179                 NewNode->Value = ObjDesc->Method.ParamCount;
    180 #else
    181                 /* Mark this as a very SPECIAL method */
    182 
    183                 ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
    184                 ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
    185 #endif
    186                 break;
    187 
    188             case ACPI_TYPE_INTEGER:
    189 
    190                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
    191                 break;
    192 
    193             case ACPI_TYPE_STRING:
    194 
    195                 /* Build an object around the static string */
    196 
    197                 ObjDesc->String.Length = (UINT32) strlen (Val);
    198                 ObjDesc->String.Pointer = Val;
    199                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
    200                 break;
    201 
    202             case ACPI_TYPE_MUTEX:
    203 
    204                 ObjDesc->Mutex.Node = NewNode;
    205                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
    206 
    207                 /* Create a mutex */
    208 
    209                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
    210                 if (ACPI_FAILURE (Status))
    211                 {
    212                     AcpiUtRemoveReference (ObjDesc);
    213                     goto UnlockAndExit;
    214                 }
    215 
    216                 /* Special case for ACPI Global Lock */
    217 
    218                 if (strcmp (InitVal->Name, "_GL_") == 0)
    219                 {
    220                     AcpiGbl_GlobalLockMutex = ObjDesc;
    221 
    222                     /* Create additional counting semaphore for global lock */
    223 
    224                     Status = AcpiOsCreateSemaphore (
    225                         1, 0, &AcpiGbl_GlobalLockSemaphore);
    226                     if (ACPI_FAILURE (Status))
    227                     {
    228                         AcpiUtRemoveReference (ObjDesc);
    229                         goto UnlockAndExit;
    230                     }
    231                 }
    232                 break;
    233 
    234             default:
    235 
    236                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
    237                     InitVal->Type));
    238                 AcpiUtRemoveReference (ObjDesc);
    239                 ObjDesc = NULL;
    240                 continue;
    241             }
    242 
    243             /* Store pointer to value descriptor in the Node */
    244 
    245             Status = AcpiNsAttachObject (NewNode, ObjDesc,
    246                 ObjDesc->Common.Type);
    247 
    248             /* Remove local reference to the object */
    249 
    250             AcpiUtRemoveReference (ObjDesc);
    251         }
    252     }
    253 
    254 
    255 UnlockAndExit:
    256     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
    257 
    258     /* Save a handle to "_GPE", it is always present */
    259 
    260     if (ACPI_SUCCESS (Status))
    261     {
    262         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
    263             &AcpiGbl_FadtGpeDevice);
    264     }
    265 
    266     return_ACPI_STATUS (Status);
    267 }
    268 
    269 
    270 /*******************************************************************************
    271  *
    272  * FUNCTION:    AcpiNsLookup
    273  *
    274  * PARAMETERS:  ScopeInfo       - Current scope info block
    275  *              Pathname        - Search pathname, in internal format
    276  *                                (as represented in the AML stream)
    277  *              Type            - Type associated with name
    278  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
    279  *              Flags           - Flags describing the search restrictions
    280  *              WalkState       - Current state of the walk
    281  *              ReturnNode      - Where the Node is placed (if found
    282  *                                or created successfully)
    283  *
    284  * RETURN:      Status
    285  *
    286  * DESCRIPTION: Find or enter the passed name in the name space.
    287  *              Log an error if name not found in Exec mode.
    288  *
    289  * MUTEX:       Assumes namespace is locked.
    290  *
    291  ******************************************************************************/
    292 
    293 ACPI_STATUS
    294 AcpiNsLookup (
    295     ACPI_GENERIC_STATE      *ScopeInfo,
    296     char                    *Pathname,
    297     ACPI_OBJECT_TYPE        Type,
    298     ACPI_INTERPRETER_MODE   InterpreterMode,
    299     UINT32                  Flags,
    300     ACPI_WALK_STATE         *WalkState,
    301     ACPI_NAMESPACE_NODE     **ReturnNode)
    302 {
    303     ACPI_STATUS             Status;
    304     char                    *Path = Pathname;
    305     char                    *ExternalPath;
    306     ACPI_NAMESPACE_NODE     *PrefixNode;
    307     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
    308     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
    309     UINT32                  NumSegments;
    310     UINT32                  NumCarats;
    311     ACPI_NAME               SimpleName;
    312     ACPI_OBJECT_TYPE        TypeToCheckFor;
    313     ACPI_OBJECT_TYPE        ThisSearchType;
    314     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
    315     UINT32                  LocalFlags;
    316     ACPI_INTERPRETER_MODE   LocalInterpreterMode;
    317 
    318 
    319     ACPI_FUNCTION_TRACE (NsLookup);
    320 
    321 
    322     if (!ReturnNode)
    323     {
    324         return_ACPI_STATUS (AE_BAD_PARAMETER);
    325     }
    326 
    327     LocalFlags = Flags &
    328         ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
    329           ACPI_NS_SEARCH_PARENT);
    330     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
    331     AcpiGbl_NsLookupCount++;
    332 
    333     if (!AcpiGbl_RootNode)
    334     {
    335         return_ACPI_STATUS (AE_NO_NAMESPACE);
    336     }
    337 
    338     /* Get the prefix scope. A null scope means use the root scope */
    339 
    340     if ((!ScopeInfo) ||
    341         (!ScopeInfo->Scope.Node))
    342     {
    343         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    344             "Null scope prefix, using root node (%p)\n",
    345             AcpiGbl_RootNode));
    346 
    347         PrefixNode = AcpiGbl_RootNode;
    348     }
    349     else
    350     {
    351         PrefixNode = ScopeInfo->Scope.Node;
    352         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
    353         {
    354             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
    355                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
    356             return_ACPI_STATUS (AE_AML_INTERNAL);
    357         }
    358 
    359         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
    360         {
    361             /*
    362              * This node might not be a actual "scope" node (such as a
    363              * Device/Method, etc.)  It could be a Package or other object
    364              * node. Backup up the tree to find the containing scope node.
    365              */
    366             while (!AcpiNsOpensScope (PrefixNode->Type) &&
    367                     PrefixNode->Type != ACPI_TYPE_ANY)
    368             {
    369                 PrefixNode = PrefixNode->Parent;
    370             }
    371         }
    372     }
    373 
    374     /* Save type. TBD: may be no longer necessary */
    375 
    376     TypeToCheckFor = Type;
    377 
    378     /*
    379      * Begin examination of the actual pathname
    380      */
    381     if (!Pathname)
    382     {
    383         /* A Null NamePath is allowed and refers to the root */
    384 
    385         NumSegments = 0;
    386         ThisNode = AcpiGbl_RootNode;
    387         Path = __UNCONST("");
    388 
    389         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    390             "Null Pathname (Zero segments), Flags=%X\n", Flags));
    391     }
    392     else
    393     {
    394         /*
    395          * Name pointer is valid (and must be in internal name format)
    396          *
    397          * Check for scope prefixes:
    398          *
    399          * As represented in the AML stream, a namepath consists of an
    400          * optional scope prefix followed by a name segment part.
    401          *
    402          * If present, the scope prefix is either a Root Prefix (in
    403          * which case the name is fully qualified), or one or more
    404          * Parent Prefixes (in which case the name's scope is relative
    405          * to the current scope).
    406          */
    407         if (*Path == (UINT8) AML_ROOT_PREFIX)
    408         {
    409             /* Pathname is fully qualified, start from the root */
    410 
    411             ThisNode = AcpiGbl_RootNode;
    412             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
    413 
    414             /* Point to name segment part */
    415 
    416             Path++;
    417 
    418             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    419                 "Path is absolute from root [%p]\n", ThisNode));
    420         }
    421         else
    422         {
    423             /* Pathname is relative to current scope, start there */
    424 
    425             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    426                 "Searching relative to prefix scope [%4.4s] (%p)\n",
    427                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
    428 
    429             /*
    430              * Handle multiple Parent Prefixes (carat) by just getting
    431              * the parent node for each prefix instance.
    432              */
    433             ThisNode = PrefixNode;
    434             NumCarats = 0;
    435             while (*Path == (UINT8) AML_PARENT_PREFIX)
    436             {
    437                 /* Name is fully qualified, no search rules apply */
    438 
    439                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
    440 
    441                 /*
    442                  * Point past this prefix to the name segment
    443                  * part or the next Parent Prefix
    444                  */
    445                 Path++;
    446 
    447                 /* Backup to the parent node */
    448 
    449                 NumCarats++;
    450                 ThisNode = ThisNode->Parent;
    451                 if (!ThisNode)
    452                 {
    453                     /*
    454                      * Current scope has no parent scope. Externalize
    455                      * the internal path for error message.
    456                      */
    457                     Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, Pathname,
    458                         NULL, &ExternalPath);
    459                     if (ACPI_SUCCESS (Status))
    460                     {
    461                         ACPI_ERROR ((AE_INFO,
    462                             "%s: Path has too many parent prefixes (^)",
    463                             ExternalPath));
    464 
    465                         ACPI_FREE (ExternalPath);
    466                     }
    467 
    468                     return_ACPI_STATUS (AE_NOT_FOUND);
    469                 }
    470             }
    471 
    472             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
    473             {
    474                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    475                     "Search scope is [%4.4s], path has %u carat(s)\n",
    476                     AcpiUtGetNodeName (ThisNode), NumCarats));
    477             }
    478         }
    479 
    480         /*
    481          * Determine the number of ACPI name segments in this pathname.
    482          *
    483          * The segment part consists of either:
    484          *  - A Null name segment (0)
    485          *  - A DualNamePrefix followed by two 4-byte name segments
    486          *  - A MultiNamePrefix followed by a byte indicating the
    487          *      number of segments and the segments themselves.
    488          *  - A single 4-byte name segment
    489          *
    490          * Examine the name prefix opcode, if any, to determine the number of
    491          * segments.
    492          */
    493         switch (*Path)
    494         {
    495         case 0:
    496             /*
    497              * Null name after a root or parent prefixes. We already
    498              * have the correct target node and there are no name segments.
    499              */
    500             NumSegments  = 0;
    501             Type = ThisNode->Type;
    502 
    503             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    504                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
    505                 Flags));
    506             break;
    507 
    508         case AML_DUAL_NAME_PREFIX:
    509 
    510             /* More than one NameSeg, search rules do not apply */
    511 
    512             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
    513 
    514             /* Two segments, point to first name segment */
    515 
    516             NumSegments = 2;
    517             Path++;
    518 
    519             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    520                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
    521             break;
    522 
    523         case AML_MULTI_NAME_PREFIX:
    524 
    525             /* More than one NameSeg, search rules do not apply */
    526 
    527             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
    528 
    529             /* Extract segment count, point to first name segment */
    530 
    531             Path++;
    532             NumSegments = (UINT32) (UINT8) *Path;
    533             Path++;
    534 
    535             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    536                 "Multi Pathname (%u Segments, Flags=%X)\n",
    537                 NumSegments, Flags));
    538             break;
    539 
    540         default:
    541             /*
    542              * Not a Null name, no Dual or Multi prefix, hence there is
    543              * only one name segment and Pathname is already pointing to it.
    544              */
    545             NumSegments = 1;
    546 
    547             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    548                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
    549             break;
    550         }
    551 
    552         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
    553     }
    554 
    555 
    556     /*
    557      * Search namespace for each segment of the name. Loop through and
    558      * verify (or add to the namespace) each name segment.
    559      *
    560      * The object type is significant only at the last name
    561      * segment. (We don't care about the types along the path, only
    562      * the type of the final target object.)
    563      */
    564     ThisSearchType = ACPI_TYPE_ANY;
    565     CurrentNode = ThisNode;
    566 
    567     while (NumSegments && CurrentNode)
    568     {
    569         NumSegments--;
    570         if (!NumSegments)
    571         {
    572             /* This is the last segment, enable typechecking */
    573 
    574             ThisSearchType = Type;
    575 
    576             /*
    577              * Only allow automatic parent search (search rules) if the caller
    578              * requested it AND we have a single, non-fully-qualified NameSeg
    579              */
    580             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
    581                 (Flags & ACPI_NS_SEARCH_PARENT))
    582             {
    583                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
    584             }
    585 
    586             /* Set error flag according to caller */
    587 
    588             if (Flags & ACPI_NS_ERROR_IF_FOUND)
    589             {
    590                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
    591             }
    592 
    593             /* Set override flag according to caller */
    594 
    595             if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
    596             {
    597                 LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
    598             }
    599         }
    600 
    601         /* Handle opcodes that create a new NameSeg via a full NamePath */
    602 
    603         LocalInterpreterMode = InterpreterMode;
    604         if ((Flags & ACPI_NS_PREFIX_MUST_EXIST) && (NumSegments > 0))
    605         {
    606             /* Every element of the path must exist (except for the final NameSeg) */
    607 
    608             LocalInterpreterMode = ACPI_IMODE_EXECUTE;
    609         }
    610 
    611         /* Extract one ACPI name from the front of the pathname */
    612 
    613         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
    614 
    615         /* Try to find the single (4 character) ACPI name */
    616 
    617         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
    618             LocalInterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
    619         if (ACPI_FAILURE (Status))
    620         {
    621             if (Status == AE_NOT_FOUND)
    622             {
    623 #if !defined ACPI_ASL_COMPILER /* Note: iASL reports this error by itself, not needed here */
    624                 if (Flags & ACPI_NS_PREFIX_MUST_EXIST)
    625                 {
    626                     AcpiOsPrintf (ACPI_MSG_BIOS_ERROR
    627                         "Object does not exist: %4.4s\n", &SimpleName);
    628                 }
    629 #endif
    630                 /* Name not found in ACPI namespace */
    631 
    632                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    633                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
    634                     (char *) &SimpleName, (char *) &CurrentNode->Name,
    635                     CurrentNode));
    636             }
    637 
    638 #ifdef ACPI_EXEC_APP
    639             if ((Status == AE_ALREADY_EXISTS) &&
    640                 (ThisNode->Flags & ANOBJ_NODE_EARLY_INIT))
    641             {
    642                 ThisNode->Flags &= ~ANOBJ_NODE_EARLY_INIT;
    643                 Status = AE_OK;
    644             }
    645 #endif
    646 
    647 #ifdef ACPI_ASL_COMPILER
    648             /*
    649              * If this ACPI name already exists within the namespace as an
    650              * external declaration, then mark the external as a conflicting
    651              * declaration and proceed to process the current node as if it did
    652              * not exist in the namespace. If this node is not processed as
    653              * normal, then it could cause improper namespace resolution
    654              * by failing to open a new scope.
    655              */
    656             if (AcpiGbl_DisasmFlag &&
    657                 (Status == AE_ALREADY_EXISTS) &&
    658                 ((ThisNode->Flags & ANOBJ_IS_EXTERNAL) ||
    659                     (WalkState && WalkState->Opcode == AML_EXTERNAL_OP)))
    660             {
    661                 ThisNode->Flags &= ~ANOBJ_IS_EXTERNAL;
    662                 ThisNode->Type = (UINT8)ThisSearchType;
    663                 if (WalkState->Opcode != AML_EXTERNAL_OP)
    664                 {
    665                     AcpiDmMarkExternalConflict (ThisNode);
    666                 }
    667                 break;
    668             }
    669 #endif
    670 
    671             *ReturnNode = ThisNode;
    672             return_ACPI_STATUS (Status);
    673         }
    674 
    675         /* More segments to follow? */
    676 
    677         if (NumSegments > 0)
    678         {
    679             /*
    680              * If we have an alias to an object that opens a scope (such as a
    681              * device or processor), we need to dereference the alias here so
    682              * that we can access any children of the original node (via the
    683              * remaining segments).
    684              */
    685             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
    686             {
    687                 if (!ThisNode->Object)
    688                 {
    689                     return_ACPI_STATUS (AE_NOT_EXIST);
    690                 }
    691 
    692                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
    693                         ThisNode->Object)->Type))
    694                 {
    695                     ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
    696                 }
    697             }
    698         }
    699 
    700         /* Special handling for the last segment (NumSegments == 0) */
    701 
    702         else
    703         {
    704             /*
    705              * Sanity typecheck of the target object:
    706              *
    707              * If 1) This is the last segment (NumSegments == 0)
    708              *    2) And we are looking for a specific type
    709              *       (Not checking for TYPE_ANY)
    710              *    3) Which is not an alias
    711              *    4) Which is not a local type (TYPE_SCOPE)
    712              *    5) And the type of target object is known (not TYPE_ANY)
    713              *    6) And target object does not match what we are looking for
    714              *
    715              * Then we have a type mismatch. Just warn and ignore it.
    716              */
    717             if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
    718                 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
    719                 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
    720                 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
    721                 (ThisNode->Type != ACPI_TYPE_ANY)                   &&
    722                 (ThisNode->Type != TypeToCheckFor))
    723             {
    724                 /* Complain about a type mismatch */
    725 
    726                 ACPI_WARNING ((AE_INFO,
    727                     "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
    728                     ACPI_CAST_PTR (char, &SimpleName),
    729                     AcpiUtGetTypeName (ThisNode->Type),
    730                     AcpiUtGetTypeName (TypeToCheckFor)));
    731             }
    732 
    733             /*
    734              * If this is the last name segment and we are not looking for a
    735              * specific type, but the type of found object is known, use that
    736              * type to (later) see if it opens a scope.
    737              */
    738             if (Type == ACPI_TYPE_ANY)
    739             {
    740                 Type = ThisNode->Type;
    741             }
    742         }
    743 
    744         /* Point to next name segment and make this node current */
    745 
    746         Path += ACPI_NAMESEG_SIZE;
    747         CurrentNode = ThisNode;
    748     }
    749 
    750     /* Always check if we need to open a new scope */
    751 
    752     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
    753     {
    754         /*
    755          * If entry is a type which opens a scope, push the new scope on the
    756          * scope stack.
    757          */
    758         if (AcpiNsOpensScope (Type))
    759         {
    760             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
    761             if (ACPI_FAILURE (Status))
    762             {
    763                 return_ACPI_STATUS (Status);
    764             }
    765         }
    766     }
    767 
    768 #ifdef ACPI_EXEC_APP
    769     if (Flags & ACPI_NS_EARLY_INIT)
    770     {
    771         ThisNode->Flags |= ANOBJ_NODE_EARLY_INIT;
    772     }
    773 #endif
    774 
    775     *ReturnNode = ThisNode;
    776     return_ACPI_STATUS (AE_OK);
    777 }
    778