xref: /freebsd/sys/contrib/dev/acpica/components/namespace/nsaccess.c (revision c36e54bb328697af1e6113812caecbd3bac89fe0)
1 /*******************************************************************************
2  *
3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2015, 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 <contrib/dev/acpica/include/acpi.h>
45 #include <contrib/dev/acpica/include/accommon.h>
46 #include <contrib/dev/acpica/include/amlcode.h>
47 #include <contrib/dev/acpica/include/acnamesp.h>
48 #include <contrib/dev/acpica/include/acdispat.h>
49 
50 
51 #define _COMPONENT          ACPI_NAMESPACE
52         ACPI_MODULE_NAME    ("nsaccess")
53 
54 
55 /*******************************************************************************
56  *
57  * FUNCTION:    AcpiNsRootInitialize
58  *
59  * PARAMETERS:  None
60  *
61  * RETURN:      Status
62  *
63  * DESCRIPTION: Allocate and initialize the default root named objects
64  *
65  * MUTEX:       Locks namespace for entire execution
66  *
67  ******************************************************************************/
68 
69 ACPI_STATUS
70 AcpiNsRootInitialize (
71     void)
72 {
73     ACPI_STATUS                 Status;
74     const ACPI_PREDEFINED_NAMES *InitVal = NULL;
75     ACPI_NAMESPACE_NODE         *NewNode;
76     ACPI_OPERAND_OBJECT         *ObjDesc;
77     ACPI_STRING                 Val = NULL;
78 
79 
80     ACPI_FUNCTION_TRACE (NsRootInitialize);
81 
82 
83     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
84     if (ACPI_FAILURE (Status))
85     {
86         return_ACPI_STATUS (Status);
87     }
88 
89     /*
90      * The global root ptr is initially NULL, so a non-NULL value indicates
91      * that AcpiNsRootInitialize() has already been called; just return.
92      */
93     if (AcpiGbl_RootNode)
94     {
95         Status = AE_OK;
96         goto UnlockAndExit;
97     }
98 
99     /*
100      * Tell the rest of the subsystem that the root is initialized
101      * (This is OK because the namespace is locked)
102      */
103     AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
104 
105     /* Enter the pre-defined names in the name table */
106 
107     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
108         "Entering predefined entries into namespace\n"));
109 
110     for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
111     {
112         /* _OSI is optional for now, will be permanent later */
113 
114         if (!strcmp (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
115         {
116             continue;
117         }
118 
119         Status = AcpiNsLookup (NULL, InitVal->Name, InitVal->Type,
120                         ACPI_IMODE_LOAD_PASS2, ACPI_NS_NO_UPSEARCH,
121                         NULL, &NewNode);
122         if (ACPI_FAILURE (Status))
123         {
124             ACPI_EXCEPTION ((AE_INFO, Status,
125                 "Could not create predefined name %s",
126                 InitVal->Name));
127             continue;
128         }
129 
130         /*
131          * Name entered successfully. If entry in PreDefinedNames[] specifies
132          * an initial value, create the initial value.
133          */
134         if (InitVal->Val)
135         {
136             Status = AcpiOsPredefinedOverride (InitVal, &Val);
137             if (ACPI_FAILURE (Status))
138             {
139                 ACPI_ERROR ((AE_INFO,
140                     "Could not override predefined %s",
141                     InitVal->Name));
142             }
143 
144             if (!Val)
145             {
146                 Val = InitVal->Val;
147             }
148 
149             /*
150              * Entry requests an initial value, allocate a
151              * descriptor for it.
152              */
153             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
154             if (!ObjDesc)
155             {
156                 Status = AE_NO_MEMORY;
157                 goto UnlockAndExit;
158             }
159 
160             /*
161              * Convert value string from table entry to
162              * internal representation. Only types actually
163              * used for initial values are implemented here.
164              */
165             switch (InitVal->Type)
166             {
167             case ACPI_TYPE_METHOD:
168 
169                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
170                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
171 
172 #if defined (ACPI_ASL_COMPILER)
173 
174                 /* Save the parameter count for the iASL compiler */
175 
176                 NewNode->Value = ObjDesc->Method.ParamCount;
177 #else
178                 /* Mark this as a very SPECIAL method */
179 
180                 ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
181                 ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
182 #endif
183                 break;
184 
185             case ACPI_TYPE_INTEGER:
186 
187                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
188                 break;
189 
190             case ACPI_TYPE_STRING:
191 
192                 /* Build an object around the static string */
193 
194                 ObjDesc->String.Length = (UINT32) strlen (Val);
195                 ObjDesc->String.Pointer = Val;
196                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
197                 break;
198 
199             case ACPI_TYPE_MUTEX:
200 
201                 ObjDesc->Mutex.Node = NewNode;
202                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
203 
204                 /* Create a mutex */
205 
206                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
207                 if (ACPI_FAILURE (Status))
208                 {
209                     AcpiUtRemoveReference (ObjDesc);
210                     goto UnlockAndExit;
211                 }
212 
213                 /* Special case for ACPI Global Lock */
214 
215                 if (strcmp (InitVal->Name, "_GL_") == 0)
216                 {
217                     AcpiGbl_GlobalLockMutex = ObjDesc;
218 
219                     /* Create additional counting semaphore for global lock */
220 
221                     Status = AcpiOsCreateSemaphore (
222                                 1, 0, &AcpiGbl_GlobalLockSemaphore);
223                     if (ACPI_FAILURE (Status))
224                     {
225                         AcpiUtRemoveReference (ObjDesc);
226                         goto UnlockAndExit;
227                     }
228                 }
229                 break;
230 
231             default:
232 
233                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
234                     InitVal->Type));
235                 AcpiUtRemoveReference (ObjDesc);
236                 ObjDesc = NULL;
237                 continue;
238             }
239 
240             /* Store pointer to value descriptor in the Node */
241 
242             Status = AcpiNsAttachObject (NewNode, ObjDesc,
243                         ObjDesc->Common.Type);
244 
245             /* Remove local reference to the object */
246 
247             AcpiUtRemoveReference (ObjDesc);
248         }
249     }
250 
251 
252 UnlockAndExit:
253     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
254 
255     /* Save a handle to "_GPE", it is always present */
256 
257     if (ACPI_SUCCESS (Status))
258     {
259         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
260                     &AcpiGbl_FadtGpeDevice);
261     }
262 
263     return_ACPI_STATUS (Status);
264 }
265 
266 
267 /*******************************************************************************
268  *
269  * FUNCTION:    AcpiNsLookup
270  *
271  * PARAMETERS:  ScopeInfo       - Current scope info block
272  *              Pathname        - Search pathname, in internal format
273  *                                (as represented in the AML stream)
274  *              Type            - Type associated with name
275  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
276  *              Flags           - Flags describing the search restrictions
277  *              WalkState       - Current state of the walk
278  *              ReturnNode      - Where the Node is placed (if found
279  *                                or created successfully)
280  *
281  * RETURN:      Status
282  *
283  * DESCRIPTION: Find or enter the passed name in the name space.
284  *              Log an error if name not found in Exec mode.
285  *
286  * MUTEX:       Assumes namespace is locked.
287  *
288  ******************************************************************************/
289 
290 ACPI_STATUS
291 AcpiNsLookup (
292     ACPI_GENERIC_STATE      *ScopeInfo,
293     char                    *Pathname,
294     ACPI_OBJECT_TYPE        Type,
295     ACPI_INTERPRETER_MODE   InterpreterMode,
296     UINT32                  Flags,
297     ACPI_WALK_STATE         *WalkState,
298     ACPI_NAMESPACE_NODE     **ReturnNode)
299 {
300     ACPI_STATUS             Status;
301     char                    *Path = Pathname;
302     ACPI_NAMESPACE_NODE     *PrefixNode;
303     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
304     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
305     UINT32                  NumSegments;
306     UINT32                  NumCarats;
307     ACPI_NAME               SimpleName;
308     ACPI_OBJECT_TYPE        TypeToCheckFor;
309     ACPI_OBJECT_TYPE        ThisSearchType;
310     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
311     UINT32                  LocalFlags;
312 
313 
314     ACPI_FUNCTION_TRACE (NsLookup);
315 
316 
317     if (!ReturnNode)
318     {
319         return_ACPI_STATUS (AE_BAD_PARAMETER);
320     }
321 
322     LocalFlags = Flags &
323         ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
324           ACPI_NS_SEARCH_PARENT);
325     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
326     AcpiGbl_NsLookupCount++;
327 
328     if (!AcpiGbl_RootNode)
329     {
330         return_ACPI_STATUS (AE_NO_NAMESPACE);
331     }
332 
333     /* Get the prefix scope. A null scope means use the root scope */
334 
335     if ((!ScopeInfo) ||
336         (!ScopeInfo->Scope.Node))
337     {
338         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
339             "Null scope prefix, using root node (%p)\n",
340             AcpiGbl_RootNode));
341 
342         PrefixNode = AcpiGbl_RootNode;
343     }
344     else
345     {
346         PrefixNode = ScopeInfo->Scope.Node;
347         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
348         {
349             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
350                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
351             return_ACPI_STATUS (AE_AML_INTERNAL);
352         }
353 
354         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
355         {
356             /*
357              * This node might not be a actual "scope" node (such as a
358              * Device/Method, etc.)  It could be a Package or other object
359              * node. Backup up the tree to find the containing scope node.
360              */
361             while (!AcpiNsOpensScope (PrefixNode->Type) &&
362                     PrefixNode->Type != ACPI_TYPE_ANY)
363             {
364                 PrefixNode = PrefixNode->Parent;
365             }
366         }
367     }
368 
369     /* Save type. TBD: may be no longer necessary */
370 
371     TypeToCheckFor = Type;
372 
373     /*
374      * Begin examination of the actual pathname
375      */
376     if (!Pathname)
377     {
378         /* A Null NamePath is allowed and refers to the root */
379 
380         NumSegments = 0;
381         ThisNode = AcpiGbl_RootNode;
382         Path = "";
383 
384         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
385             "Null Pathname (Zero segments), Flags=%X\n", Flags));
386     }
387     else
388     {
389         /*
390          * Name pointer is valid (and must be in internal name format)
391          *
392          * Check for scope prefixes:
393          *
394          * As represented in the AML stream, a namepath consists of an
395          * optional scope prefix followed by a name segment part.
396          *
397          * If present, the scope prefix is either a Root Prefix (in
398          * which case the name is fully qualified), or one or more
399          * Parent Prefixes (in which case the name's scope is relative
400          * to the current scope).
401          */
402         if (*Path == (UINT8) AML_ROOT_PREFIX)
403         {
404             /* Pathname is fully qualified, start from the root */
405 
406             ThisNode = AcpiGbl_RootNode;
407             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
408 
409             /* Point to name segment part */
410 
411             Path++;
412 
413             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
414                 "Path is absolute from root [%p]\n", ThisNode));
415         }
416         else
417         {
418             /* Pathname is relative to current scope, start there */
419 
420             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
421                 "Searching relative to prefix scope [%4.4s] (%p)\n",
422                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
423 
424             /*
425              * Handle multiple Parent Prefixes (carat) by just getting
426              * the parent node for each prefix instance.
427              */
428             ThisNode = PrefixNode;
429             NumCarats = 0;
430             while (*Path == (UINT8) AML_PARENT_PREFIX)
431             {
432                 /* Name is fully qualified, no search rules apply */
433 
434                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
435 
436                 /*
437                  * Point past this prefix to the name segment
438                  * part or the next Parent Prefix
439                  */
440                 Path++;
441 
442                 /* Backup to the parent node */
443 
444                 NumCarats++;
445                 ThisNode = ThisNode->Parent;
446                 if (!ThisNode)
447                 {
448                     /* Current scope has no parent scope */
449 
450                     ACPI_ERROR ((AE_INFO,
451                         "%s: Path has too many parent prefixes (^) "
452                         "- reached beyond root node", Pathname));
453                     return_ACPI_STATUS (AE_NOT_FOUND);
454                 }
455             }
456 
457             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
458             {
459                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
460                     "Search scope is [%4.4s], path has %u carat(s)\n",
461                     AcpiUtGetNodeName (ThisNode), NumCarats));
462             }
463         }
464 
465         /*
466          * Determine the number of ACPI name segments in this pathname.
467          *
468          * The segment part consists of either:
469          *  - A Null name segment (0)
470          *  - A DualNamePrefix followed by two 4-byte name segments
471          *  - A MultiNamePrefix followed by a byte indicating the
472          *      number of segments and the segments themselves.
473          *  - A single 4-byte name segment
474          *
475          * Examine the name prefix opcode, if any, to determine the number of
476          * segments.
477          */
478         switch (*Path)
479         {
480         case 0:
481             /*
482              * Null name after a root or parent prefixes. We already
483              * have the correct target node and there are no name segments.
484              */
485             NumSegments  = 0;
486             Type = ThisNode->Type;
487 
488             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
489                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
490                 Flags));
491             break;
492 
493         case AML_DUAL_NAME_PREFIX:
494 
495             /* More than one NameSeg, search rules do not apply */
496 
497             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
498 
499             /* Two segments, point to first name segment */
500 
501             NumSegments = 2;
502             Path++;
503 
504             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
505                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
506             break;
507 
508         case AML_MULTI_NAME_PREFIX_OP:
509 
510             /* More than one NameSeg, search rules do not apply */
511 
512             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
513 
514             /* Extract segment count, point to first name segment */
515 
516             Path++;
517             NumSegments = (UINT32) (UINT8) *Path;
518             Path++;
519 
520             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
521                 "Multi Pathname (%u Segments, Flags=%X)\n",
522                 NumSegments, Flags));
523             break;
524 
525         default:
526             /*
527              * Not a Null name, no Dual or Multi prefix, hence there is
528              * only one name segment and Pathname is already pointing to it.
529              */
530             NumSegments = 1;
531 
532             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
533                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
534             break;
535         }
536 
537         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
538     }
539 
540 
541     /*
542      * Search namespace for each segment of the name. Loop through and
543      * verify (or add to the namespace) each name segment.
544      *
545      * The object type is significant only at the last name
546      * segment. (We don't care about the types along the path, only
547      * the type of the final target object.)
548      */
549     ThisSearchType = ACPI_TYPE_ANY;
550     CurrentNode = ThisNode;
551     while (NumSegments && CurrentNode)
552     {
553         NumSegments--;
554         if (!NumSegments)
555         {
556             /* This is the last segment, enable typechecking */
557 
558             ThisSearchType = Type;
559 
560             /*
561              * Only allow automatic parent search (search rules) if the caller
562              * requested it AND we have a single, non-fully-qualified NameSeg
563              */
564             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
565                 (Flags & ACPI_NS_SEARCH_PARENT))
566             {
567                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
568             }
569 
570             /* Set error flag according to caller */
571 
572             if (Flags & ACPI_NS_ERROR_IF_FOUND)
573             {
574                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
575             }
576 
577             /* Set override flag according to caller */
578 
579             if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
580             {
581                 LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
582             }
583         }
584 
585         /* Extract one ACPI name from the front of the pathname */
586 
587         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
588 
589         /* Try to find the single (4 character) ACPI name */
590 
591         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
592                     InterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
593         if (ACPI_FAILURE (Status))
594         {
595             if (Status == AE_NOT_FOUND)
596             {
597                 /* Name not found in ACPI namespace */
598 
599                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
600                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
601                     (char *) &SimpleName, (char *) &CurrentNode->Name,
602                     CurrentNode));
603             }
604 
605             *ReturnNode = ThisNode;
606             return_ACPI_STATUS (Status);
607         }
608 
609         /* More segments to follow? */
610 
611         if (NumSegments > 0)
612         {
613             /*
614              * If we have an alias to an object that opens a scope (such as a
615              * device or processor), we need to dereference the alias here so
616              * that we can access any children of the original node (via the
617              * remaining segments).
618              */
619             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
620             {
621                 if (!ThisNode->Object)
622                 {
623                     return_ACPI_STATUS (AE_NOT_EXIST);
624                 }
625 
626                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
627                         ThisNode->Object)->Type))
628                 {
629                     ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
630                 }
631             }
632         }
633 
634         /* Special handling for the last segment (NumSegments == 0) */
635 
636         else
637         {
638             /*
639              * Sanity typecheck of the target object:
640              *
641              * If 1) This is the last segment (NumSegments == 0)
642              *    2) And we are looking for a specific type
643              *       (Not checking for TYPE_ANY)
644              *    3) Which is not an alias
645              *    4) Which is not a local type (TYPE_SCOPE)
646              *    5) And the type of target object is known (not TYPE_ANY)
647              *    6) And target object does not match what we are looking for
648              *
649              * Then we have a type mismatch. Just warn and ignore it.
650              */
651             if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
652                 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
653                 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
654                 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
655                 (ThisNode->Type != ACPI_TYPE_ANY)                   &&
656                 (ThisNode->Type != TypeToCheckFor))
657             {
658                 /* Complain about a type mismatch */
659 
660                 ACPI_WARNING ((AE_INFO,
661                     "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
662                     ACPI_CAST_PTR (char, &SimpleName),
663                     AcpiUtGetTypeName (ThisNode->Type),
664                     AcpiUtGetTypeName (TypeToCheckFor)));
665             }
666 
667             /*
668              * If this is the last name segment and we are not looking for a
669              * specific type, but the type of found object is known, use that
670              * type to (later) see if it opens a scope.
671              */
672             if (Type == ACPI_TYPE_ANY)
673             {
674                 Type = ThisNode->Type;
675             }
676         }
677 
678         /* Point to next name segment and make this node current */
679 
680         Path += ACPI_NAME_SIZE;
681         CurrentNode = ThisNode;
682     }
683 
684     /* Always check if we need to open a new scope */
685 
686     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
687     {
688         /*
689          * If entry is a type which opens a scope, push the new scope on the
690          * scope stack.
691          */
692         if (AcpiNsOpensScope (Type))
693         {
694             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
695             if (ACPI_FAILURE (Status))
696             {
697                 return_ACPI_STATUS (Status);
698             }
699         }
700     }
701 
702     *ReturnNode = ThisNode;
703     return_ACPI_STATUS (AE_OK);
704 }
705