xref: /freebsd/sys/contrib/dev/acpica/components/namespace/nsaccess.c (revision ea825d02749f382c3f7e17f28247f20a48733eab)
1 /*******************************************************************************
2  *
3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
4  *
5  ******************************************************************************/
6 
7 /******************************************************************************
8  *
9  * 1. Copyright Notice
10  *
11  * Some or all of this work - Copyright (c) 1999 - 2017, 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 <contrib/dev/acpica/include/acpi.h>
153 #include <contrib/dev/acpica/include/accommon.h>
154 #include <contrib/dev/acpica/include/amlcode.h>
155 #include <contrib/dev/acpica/include/acnamesp.h>
156 #include <contrib/dev/acpica/include/acdispat.h>
157 
158 #ifdef ACPI_ASL_COMPILER
159     #include <contrib/dev/acpica/include/acdisasm.h>
160 #endif
161 
162 #define _COMPONENT          ACPI_NAMESPACE
163         ACPI_MODULE_NAME    ("nsaccess")
164 
165 
166 /*******************************************************************************
167  *
168  * FUNCTION:    AcpiNsRootInitialize
169  *
170  * PARAMETERS:  None
171  *
172  * RETURN:      Status
173  *
174  * DESCRIPTION: Allocate and initialize the default root named objects
175  *
176  * MUTEX:       Locks namespace for entire execution
177  *
178  ******************************************************************************/
179 
180 ACPI_STATUS
181 AcpiNsRootInitialize (
182     void)
183 {
184     ACPI_STATUS                 Status;
185     const ACPI_PREDEFINED_NAMES *InitVal = NULL;
186     ACPI_NAMESPACE_NODE         *NewNode;
187     ACPI_OPERAND_OBJECT         *ObjDesc;
188     ACPI_STRING                 Val = NULL;
189 
190 
191     ACPI_FUNCTION_TRACE (NsRootInitialize);
192 
193 
194     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
195     if (ACPI_FAILURE (Status))
196     {
197         return_ACPI_STATUS (Status);
198     }
199 
200     /*
201      * The global root ptr is initially NULL, so a non-NULL value indicates
202      * that AcpiNsRootInitialize() has already been called; just return.
203      */
204     if (AcpiGbl_RootNode)
205     {
206         Status = AE_OK;
207         goto UnlockAndExit;
208     }
209 
210     /*
211      * Tell the rest of the subsystem that the root is initialized
212      * (This is OK because the namespace is locked)
213      */
214     AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
215 
216     /* Enter the pre-defined names in the name table */
217 
218     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
219         "Entering predefined entries into namespace\n"));
220 
221     for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
222     {
223         /* _OSI is optional for now, will be permanent later */
224 
225         if (!strcmp (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
226         {
227             continue;
228         }
229 
230         Status = AcpiNsLookup (NULL, ACPI_CAST_PTR (char, InitVal->Name),
231             InitVal->Type, ACPI_IMODE_LOAD_PASS2, ACPI_NS_NO_UPSEARCH,
232             NULL, &NewNode);
233         if (ACPI_FAILURE (Status))
234         {
235             ACPI_EXCEPTION ((AE_INFO, Status,
236                 "Could not create predefined name %s",
237                 InitVal->Name));
238             continue;
239         }
240 
241         /*
242          * Name entered successfully. If entry in PreDefinedNames[] specifies
243          * an initial value, create the initial value.
244          */
245         if (InitVal->Val)
246         {
247             Status = AcpiOsPredefinedOverride (InitVal, &Val);
248             if (ACPI_FAILURE (Status))
249             {
250                 ACPI_ERROR ((AE_INFO,
251                     "Could not override predefined %s",
252                     InitVal->Name));
253             }
254 
255             if (!Val)
256             {
257                 Val = InitVal->Val;
258             }
259 
260             /*
261              * Entry requests an initial value, allocate a
262              * descriptor for it.
263              */
264             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
265             if (!ObjDesc)
266             {
267                 Status = AE_NO_MEMORY;
268                 goto UnlockAndExit;
269             }
270 
271             /*
272              * Convert value string from table entry to
273              * internal representation. Only types actually
274              * used for initial values are implemented here.
275              */
276             switch (InitVal->Type)
277             {
278             case ACPI_TYPE_METHOD:
279 
280                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
281                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
282 
283 #if defined (ACPI_ASL_COMPILER)
284 
285                 /* Save the parameter count for the iASL compiler */
286 
287                 NewNode->Value = ObjDesc->Method.ParamCount;
288 #else
289                 /* Mark this as a very SPECIAL method */
290 
291                 ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
292                 ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
293 #endif
294                 break;
295 
296             case ACPI_TYPE_INTEGER:
297 
298                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
299                 break;
300 
301             case ACPI_TYPE_STRING:
302 
303                 /* Build an object around the static string */
304 
305                 ObjDesc->String.Length = (UINT32) strlen (Val);
306                 ObjDesc->String.Pointer = Val;
307                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
308                 break;
309 
310             case ACPI_TYPE_MUTEX:
311 
312                 ObjDesc->Mutex.Node = NewNode;
313                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
314 
315                 /* Create a mutex */
316 
317                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
318                 if (ACPI_FAILURE (Status))
319                 {
320                     AcpiUtRemoveReference (ObjDesc);
321                     goto UnlockAndExit;
322                 }
323 
324                 /* Special case for ACPI Global Lock */
325 
326                 if (strcmp (InitVal->Name, "_GL_") == 0)
327                 {
328                     AcpiGbl_GlobalLockMutex = ObjDesc;
329 
330                     /* Create additional counting semaphore for global lock */
331 
332                     Status = AcpiOsCreateSemaphore (
333                         1, 0, &AcpiGbl_GlobalLockSemaphore);
334                     if (ACPI_FAILURE (Status))
335                     {
336                         AcpiUtRemoveReference (ObjDesc);
337                         goto UnlockAndExit;
338                     }
339                 }
340                 break;
341 
342             default:
343 
344                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
345                     InitVal->Type));
346                 AcpiUtRemoveReference (ObjDesc);
347                 ObjDesc = NULL;
348                 continue;
349             }
350 
351             /* Store pointer to value descriptor in the Node */
352 
353             Status = AcpiNsAttachObject (NewNode, ObjDesc,
354                 ObjDesc->Common.Type);
355 
356             /* Remove local reference to the object */
357 
358             AcpiUtRemoveReference (ObjDesc);
359         }
360     }
361 
362 
363 UnlockAndExit:
364     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
365 
366     /* Save a handle to "_GPE", it is always present */
367 
368     if (ACPI_SUCCESS (Status))
369     {
370         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
371             &AcpiGbl_FadtGpeDevice);
372     }
373 
374     return_ACPI_STATUS (Status);
375 }
376 
377 
378 /*******************************************************************************
379  *
380  * FUNCTION:    AcpiNsLookup
381  *
382  * PARAMETERS:  ScopeInfo       - Current scope info block
383  *              Pathname        - Search pathname, in internal format
384  *                                (as represented in the AML stream)
385  *              Type            - Type associated with name
386  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
387  *              Flags           - Flags describing the search restrictions
388  *              WalkState       - Current state of the walk
389  *              ReturnNode      - Where the Node is placed (if found
390  *                                or created successfully)
391  *
392  * RETURN:      Status
393  *
394  * DESCRIPTION: Find or enter the passed name in the name space.
395  *              Log an error if name not found in Exec mode.
396  *
397  * MUTEX:       Assumes namespace is locked.
398  *
399  ******************************************************************************/
400 
401 ACPI_STATUS
402 AcpiNsLookup (
403     ACPI_GENERIC_STATE      *ScopeInfo,
404     char                    *Pathname,
405     ACPI_OBJECT_TYPE        Type,
406     ACPI_INTERPRETER_MODE   InterpreterMode,
407     UINT32                  Flags,
408     ACPI_WALK_STATE         *WalkState,
409     ACPI_NAMESPACE_NODE     **ReturnNode)
410 {
411     ACPI_STATUS             Status;
412     char                    *Path = Pathname;
413     char                    *ExternalPath;
414     ACPI_NAMESPACE_NODE     *PrefixNode;
415     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
416     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
417     UINT32                  NumSegments;
418     UINT32                  NumCarats;
419     ACPI_NAME               SimpleName;
420     ACPI_OBJECT_TYPE        TypeToCheckFor;
421     ACPI_OBJECT_TYPE        ThisSearchType;
422     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
423     UINT32                  LocalFlags;
424 
425 
426     ACPI_FUNCTION_TRACE (NsLookup);
427 
428 
429     if (!ReturnNode)
430     {
431         return_ACPI_STATUS (AE_BAD_PARAMETER);
432     }
433 
434     LocalFlags = Flags &
435         ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
436           ACPI_NS_SEARCH_PARENT);
437     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
438     AcpiGbl_NsLookupCount++;
439 
440     if (!AcpiGbl_RootNode)
441     {
442         return_ACPI_STATUS (AE_NO_NAMESPACE);
443     }
444 
445     /* Get the prefix scope. A null scope means use the root scope */
446 
447     if ((!ScopeInfo) ||
448         (!ScopeInfo->Scope.Node))
449     {
450         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
451             "Null scope prefix, using root node (%p)\n",
452             AcpiGbl_RootNode));
453 
454         PrefixNode = AcpiGbl_RootNode;
455     }
456     else
457     {
458         PrefixNode = ScopeInfo->Scope.Node;
459         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
460         {
461             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
462                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
463             return_ACPI_STATUS (AE_AML_INTERNAL);
464         }
465 
466         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
467         {
468             /*
469              * This node might not be a actual "scope" node (such as a
470              * Device/Method, etc.)  It could be a Package or other object
471              * node. Backup up the tree to find the containing scope node.
472              */
473             while (!AcpiNsOpensScope (PrefixNode->Type) &&
474                     PrefixNode->Type != ACPI_TYPE_ANY)
475             {
476                 PrefixNode = PrefixNode->Parent;
477             }
478         }
479     }
480 
481     /* Save type. TBD: may be no longer necessary */
482 
483     TypeToCheckFor = Type;
484 
485     /*
486      * Begin examination of the actual pathname
487      */
488     if (!Pathname)
489     {
490         /* A Null NamePath is allowed and refers to the root */
491 
492         NumSegments = 0;
493         ThisNode = AcpiGbl_RootNode;
494         Path = "";
495 
496         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
497             "Null Pathname (Zero segments), Flags=%X\n", Flags));
498     }
499     else
500     {
501         /*
502          * Name pointer is valid (and must be in internal name format)
503          *
504          * Check for scope prefixes:
505          *
506          * As represented in the AML stream, a namepath consists of an
507          * optional scope prefix followed by a name segment part.
508          *
509          * If present, the scope prefix is either a Root Prefix (in
510          * which case the name is fully qualified), or one or more
511          * Parent Prefixes (in which case the name's scope is relative
512          * to the current scope).
513          */
514         if (*Path == (UINT8) AML_ROOT_PREFIX)
515         {
516             /* Pathname is fully qualified, start from the root */
517 
518             ThisNode = AcpiGbl_RootNode;
519             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
520 
521             /* Point to name segment part */
522 
523             Path++;
524 
525             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
526                 "Path is absolute from root [%p]\n", ThisNode));
527         }
528         else
529         {
530             /* Pathname is relative to current scope, start there */
531 
532             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
533                 "Searching relative to prefix scope [%4.4s] (%p)\n",
534                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
535 
536             /*
537              * Handle multiple Parent Prefixes (carat) by just getting
538              * the parent node for each prefix instance.
539              */
540             ThisNode = PrefixNode;
541             NumCarats = 0;
542             while (*Path == (UINT8) AML_PARENT_PREFIX)
543             {
544                 /* Name is fully qualified, no search rules apply */
545 
546                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
547 
548                 /*
549                  * Point past this prefix to the name segment
550                  * part or the next Parent Prefix
551                  */
552                 Path++;
553 
554                 /* Backup to the parent node */
555 
556                 NumCarats++;
557                 ThisNode = ThisNode->Parent;
558                 if (!ThisNode)
559                 {
560                     /*
561                      * Current scope has no parent scope. Externalize
562                      * the internal path for error message.
563                      */
564                     Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, Pathname,
565                         NULL, &ExternalPath);
566                     if (ACPI_SUCCESS (Status))
567                     {
568                         ACPI_ERROR ((AE_INFO,
569                             "%s: Path has too many parent prefixes (^)",
570                             ExternalPath));
571 
572                         ACPI_FREE (ExternalPath);
573                     }
574 
575                     return_ACPI_STATUS (AE_NOT_FOUND);
576                 }
577             }
578 
579             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
580             {
581                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
582                     "Search scope is [%4.4s], path has %u carat(s)\n",
583                     AcpiUtGetNodeName (ThisNode), NumCarats));
584             }
585         }
586 
587         /*
588          * Determine the number of ACPI name segments in this pathname.
589          *
590          * The segment part consists of either:
591          *  - A Null name segment (0)
592          *  - A DualNamePrefix followed by two 4-byte name segments
593          *  - A MultiNamePrefix followed by a byte indicating the
594          *      number of segments and the segments themselves.
595          *  - A single 4-byte name segment
596          *
597          * Examine the name prefix opcode, if any, to determine the number of
598          * segments.
599          */
600         switch (*Path)
601         {
602         case 0:
603             /*
604              * Null name after a root or parent prefixes. We already
605              * have the correct target node and there are no name segments.
606              */
607             NumSegments  = 0;
608             Type = ThisNode->Type;
609 
610             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
611                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
612                 Flags));
613             break;
614 
615         case AML_DUAL_NAME_PREFIX:
616 
617             /* More than one NameSeg, search rules do not apply */
618 
619             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
620 
621             /* Two segments, point to first name segment */
622 
623             NumSegments = 2;
624             Path++;
625 
626             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
627                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
628             break;
629 
630         case AML_MULTI_NAME_PREFIX:
631 
632             /* More than one NameSeg, search rules do not apply */
633 
634             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
635 
636             /* Extract segment count, point to first name segment */
637 
638             Path++;
639             NumSegments = (UINT32) (UINT8) *Path;
640             Path++;
641 
642             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
643                 "Multi Pathname (%u Segments, Flags=%X)\n",
644                 NumSegments, Flags));
645             break;
646 
647         default:
648             /*
649              * Not a Null name, no Dual or Multi prefix, hence there is
650              * only one name segment and Pathname is already pointing to it.
651              */
652             NumSegments = 1;
653 
654             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
655                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
656             break;
657         }
658 
659         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
660     }
661 
662 
663     /*
664      * Search namespace for each segment of the name. Loop through and
665      * verify (or add to the namespace) each name segment.
666      *
667      * The object type is significant only at the last name
668      * segment. (We don't care about the types along the path, only
669      * the type of the final target object.)
670      */
671     ThisSearchType = ACPI_TYPE_ANY;
672     CurrentNode = ThisNode;
673     while (NumSegments && CurrentNode)
674     {
675         NumSegments--;
676         if (!NumSegments)
677         {
678             /* This is the last segment, enable typechecking */
679 
680             ThisSearchType = Type;
681 
682             /*
683              * Only allow automatic parent search (search rules) if the caller
684              * requested it AND we have a single, non-fully-qualified NameSeg
685              */
686             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
687                 (Flags & ACPI_NS_SEARCH_PARENT))
688             {
689                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
690             }
691 
692             /* Set error flag according to caller */
693 
694             if (Flags & ACPI_NS_ERROR_IF_FOUND)
695             {
696                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
697             }
698 
699             /* Set override flag according to caller */
700 
701             if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
702             {
703                 LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
704             }
705         }
706 
707         /* Extract one ACPI name from the front of the pathname */
708 
709         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
710 
711         /* Try to find the single (4 character) ACPI name */
712 
713         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
714             InterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
715         if (ACPI_FAILURE (Status))
716         {
717             if (Status == AE_NOT_FOUND)
718             {
719                 /* Name not found in ACPI namespace */
720 
721                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
722                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
723                     (char *) &SimpleName, (char *) &CurrentNode->Name,
724                     CurrentNode));
725             }
726 
727 #ifdef ACPI_ASL_COMPILER
728             /*
729              * If this ACPI name already exists within the namespace as an
730              * external declaration, then mark the external as a conflicting
731              * declaration and proceed to process the current node as if it did
732              * not exist in the namespace. If this node is not processed as
733              * normal, then it could cause improper namespace resolution
734              * by failing to open a new scope.
735              */
736             if (AcpiGbl_DisasmFlag &&
737                 (Status == AE_ALREADY_EXISTS) &&
738                 ((ThisNode->Flags & ANOBJ_IS_EXTERNAL) ||
739                     (WalkState && WalkState->Opcode == AML_EXTERNAL_OP)))
740             {
741                 ThisNode->Flags &= ~ANOBJ_IS_EXTERNAL;
742                 ThisNode->Type = (UINT8)ThisSearchType;
743                 if (WalkState->Opcode != AML_EXTERNAL_OP)
744                 {
745                     AcpiDmMarkExternalConflict (ThisNode);
746                 }
747                 break;
748             }
749 #endif
750 
751             *ReturnNode = ThisNode;
752             return_ACPI_STATUS (Status);
753         }
754 
755         /* More segments to follow? */
756 
757         if (NumSegments > 0)
758         {
759             /*
760              * If we have an alias to an object that opens a scope (such as a
761              * device or processor), we need to dereference the alias here so
762              * that we can access any children of the original node (via the
763              * remaining segments).
764              */
765             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
766             {
767                 if (!ThisNode->Object)
768                 {
769                     return_ACPI_STATUS (AE_NOT_EXIST);
770                 }
771 
772                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
773                         ThisNode->Object)->Type))
774                 {
775                     ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
776                 }
777             }
778         }
779 
780         /* Special handling for the last segment (NumSegments == 0) */
781 
782         else
783         {
784 #ifdef ACPI_ASL_COMPILER
785             if (!AcpiGbl_DisasmFlag && (ThisNode->Flags & ANOBJ_IS_EXTERNAL))
786             {
787                 ThisNode->Flags &= ~IMPLICIT_EXTERNAL;
788             }
789 #endif
790 
791             /*
792              * Sanity typecheck of the target object:
793              *
794              * If 1) This is the last segment (NumSegments == 0)
795              *    2) And we are looking for a specific type
796              *       (Not checking for TYPE_ANY)
797              *    3) Which is not an alias
798              *    4) Which is not a local type (TYPE_SCOPE)
799              *    5) And the type of target object is known (not TYPE_ANY)
800              *    6) And target object does not match what we are looking for
801              *
802              * Then we have a type mismatch. Just warn and ignore it.
803              */
804             if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
805                 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
806                 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
807                 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
808                 (ThisNode->Type != ACPI_TYPE_ANY)                   &&
809                 (ThisNode->Type != TypeToCheckFor))
810             {
811                 /* Complain about a type mismatch */
812 
813                 ACPI_WARNING ((AE_INFO,
814                     "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
815                     ACPI_CAST_PTR (char, &SimpleName),
816                     AcpiUtGetTypeName (ThisNode->Type),
817                     AcpiUtGetTypeName (TypeToCheckFor)));
818             }
819 
820             /*
821              * If this is the last name segment and we are not looking for a
822              * specific type, but the type of found object is known, use that
823              * type to (later) see if it opens a scope.
824              */
825             if (Type == ACPI_TYPE_ANY)
826             {
827                 Type = ThisNode->Type;
828             }
829         }
830 
831         /* Point to next name segment and make this node current */
832 
833         Path += ACPI_NAME_SIZE;
834         CurrentNode = ThisNode;
835     }
836 
837     /* Always check if we need to open a new scope */
838 
839     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
840     {
841         /*
842          * If entry is a type which opens a scope, push the new scope on the
843          * scope stack.
844          */
845         if (AcpiNsOpensScope (Type))
846         {
847             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
848             if (ACPI_FAILURE (Status))
849             {
850                 return_ACPI_STATUS (Status);
851             }
852         }
853     }
854 
855     *ReturnNode = ThisNode;
856     return_ACPI_STATUS (AE_OK);
857 }
858