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 = 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 = "";
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_NAME_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