xref: /freebsd/sys/contrib/dev/acpica/components/namespace/nsaccess.c (revision 722b16673c40aedf280895f2f2f676bb494518d7)
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 - 2023, 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
AcpiNsRootInitialize(void)181 AcpiNsRootInitialize (
182     void)
183 {
184     ACPI_STATUS                 Status;
185     const ACPI_PREDEFINED_NAMES *InitVal = NULL;
186     ACPI_NAMESPACE_NODE         *NewNode;
187     ACPI_NAMESPACE_NODE         *PrevNode = NULL;
188     ACPI_OPERAND_OBJECT         *ObjDesc;
189     ACPI_STRING                 Val = NULL;
190 
191 
192     ACPI_FUNCTION_TRACE (NsRootInitialize);
193 
194 
195     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
196     if (ACPI_FAILURE (Status))
197     {
198         return_ACPI_STATUS (Status);
199     }
200 
201     /*
202      * The global root ptr is initially NULL, so a non-NULL value indicates
203      * that AcpiNsRootInitialize() has already been called; just return.
204      */
205     if (AcpiGbl_RootNode)
206     {
207         Status = AE_OK;
208         goto UnlockAndExit;
209     }
210 
211     /*
212      * Tell the rest of the subsystem that the root is initialized
213      * (This is OK because the namespace is locked)
214      */
215     AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
216 
217     /* Enter the predefined names in the name table */
218 
219     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
220         "Entering predefined entries into namespace\n"));
221 
222     /*
223      * Create the initial (default) namespace.
224      * This namespace looks like something similar to this:
225      *
226      *   ACPI Namespace (from Namespace Root):
227      *    0  _GPE Scope        00203160 00
228      *    0  _PR_ Scope        002031D0 00
229      *    0  _SB_ Device       00203240 00 Notify Object: 0020ADD8
230      *    0  _SI_ Scope        002032B0 00
231      *    0  _TZ_ Device       00203320 00
232      *    0  _REV Integer      00203390 00 = 0000000000000002
233      *    0  _OS_ String       00203488 00 Len 14 "Microsoft Windows NT"
234      *    0  _GL_ Mutex        00203580 00 Object 002035F0
235      *    0  _OSI Method       00203678 00 Args 1 Len 0000 Aml 00000000
236      */
237     for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
238     {
239         Status = AE_OK;
240 
241         /* _OSI is optional for now, will be permanent later */
242 
243         if (!strcmp (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
244         {
245             continue;
246         }
247 
248         /*
249          * Create, init, and link the new predefined name
250          * Note: No need to use AcpiNsLookup here because all the
251          * predefined names are at the root level. It is much easier to
252          * just create and link the new node(s) here.
253          */
254         NewNode = AcpiNsCreateNode (*ACPI_CAST_PTR (UINT32, InitVal->Name));
255         if (!NewNode)
256         {
257             Status = AE_NO_MEMORY;
258             goto UnlockAndExit;
259         }
260 
261         NewNode->DescriptorType = ACPI_DESC_TYPE_NAMED;
262         NewNode->Type = InitVal->Type;
263 
264         if (!PrevNode)
265         {
266             AcpiGbl_RootNodeStruct.Child = NewNode;
267         }
268         else
269         {
270             PrevNode->Peer = NewNode;
271         }
272 
273         NewNode->Parent = &AcpiGbl_RootNodeStruct;
274         PrevNode = NewNode;
275 
276         /*
277          * Name entered successfully. If entry in PreDefinedNames[] specifies
278          * an initial value, create the initial value.
279          */
280         if (InitVal->Val)
281         {
282             Status = AcpiOsPredefinedOverride (InitVal, &Val);
283             if (ACPI_FAILURE (Status))
284             {
285                 ACPI_ERROR ((AE_INFO,
286                     "Could not override predefined %s",
287                     InitVal->Name));
288             }
289 
290             if (!Val)
291             {
292                 Val = InitVal->Val;
293             }
294 
295             /*
296              * Entry requests an initial value, allocate a
297              * descriptor for it.
298              */
299             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
300             if (!ObjDesc)
301             {
302                 Status = AE_NO_MEMORY;
303                 goto UnlockAndExit;
304             }
305 
306             /*
307              * Convert value string from table entry to
308              * internal representation. Only types actually
309              * used for initial values are implemented here.
310              */
311             switch (InitVal->Type)
312             {
313             case ACPI_TYPE_METHOD:
314 
315                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
316                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
317 
318 #if defined (ACPI_ASL_COMPILER)
319 
320                 /* Save the parameter count for the iASL compiler */
321 
322                 NewNode->Value = ObjDesc->Method.ParamCount;
323 #else
324                 /* Mark this as a very SPECIAL method (_OSI) */
325 
326                 ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
327                 ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
328 #endif
329                 break;
330 
331             case ACPI_TYPE_INTEGER:
332 
333                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
334                 break;
335 
336             case ACPI_TYPE_STRING:
337 
338                 /* Build an object around the static string */
339 
340                 ObjDesc->String.Length = (UINT32) strlen (Val);
341                 ObjDesc->String.Pointer = Val;
342                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
343                 break;
344 
345             case ACPI_TYPE_MUTEX:
346 
347                 ObjDesc->Mutex.Node = NewNode;
348                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
349 
350                 /* Create a mutex */
351 
352                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
353                 if (ACPI_FAILURE (Status))
354                 {
355                     AcpiUtRemoveReference (ObjDesc);
356                     goto UnlockAndExit;
357                 }
358 
359                 /* Special case for ACPI Global Lock */
360 
361                 if (strcmp (InitVal->Name, "_GL_") == 0)
362                 {
363                     AcpiGbl_GlobalLockMutex = ObjDesc;
364 
365                     /* Create additional counting semaphore for global lock */
366 
367                     Status = AcpiOsCreateSemaphore (
368                         1, 0, &AcpiGbl_GlobalLockSemaphore);
369                     if (ACPI_FAILURE (Status))
370                     {
371                         AcpiUtRemoveReference (ObjDesc);
372                         goto UnlockAndExit;
373                     }
374                 }
375                 break;
376 
377             default:
378 
379                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
380                     InitVal->Type));
381                 AcpiUtRemoveReference (ObjDesc);
382                 ObjDesc = NULL;
383                 continue;
384             }
385 
386             /* Store pointer to value descriptor in the Node */
387 
388             Status = AcpiNsAttachObject (NewNode, ObjDesc,
389                 ObjDesc->Common.Type);
390 
391             /* Remove local reference to the object */
392 
393             AcpiUtRemoveReference (ObjDesc);
394         }
395     }
396 
397 UnlockAndExit:
398     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
399 
400     /* Save a handle to "_GPE", it is always present */
401 
402     if (ACPI_SUCCESS (Status))
403     {
404         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
405             &AcpiGbl_FadtGpeDevice);
406     }
407 
408     return_ACPI_STATUS (Status);
409 }
410 
411 
412 /*******************************************************************************
413  *
414  * FUNCTION:    AcpiNsLookup
415  *
416  * PARAMETERS:  ScopeInfo       - Current scope info block
417  *              Pathname        - Search pathname, in internal format
418  *                                (as represented in the AML stream)
419  *              Type            - Type associated with name
420  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
421  *              Flags           - Flags describing the search restrictions
422  *              WalkState       - Current state of the walk
423  *              ReturnNode      - Where the Node is placed (if found
424  *                                or created successfully)
425  *
426  * RETURN:      Status
427  *
428  * DESCRIPTION: Find or enter the passed name in the name space.
429  *              Log an error if name not found in Exec mode.
430  *
431  * MUTEX:       Assumes namespace is locked.
432  *
433  ******************************************************************************/
434 
435 ACPI_STATUS
AcpiNsLookup(ACPI_GENERIC_STATE * ScopeInfo,char * Pathname,ACPI_OBJECT_TYPE Type,ACPI_INTERPRETER_MODE InterpreterMode,UINT32 Flags,ACPI_WALK_STATE * WalkState,ACPI_NAMESPACE_NODE ** ReturnNode)436 AcpiNsLookup (
437     ACPI_GENERIC_STATE      *ScopeInfo,
438     char                    *Pathname,
439     ACPI_OBJECT_TYPE        Type,
440     ACPI_INTERPRETER_MODE   InterpreterMode,
441     UINT32                  Flags,
442     ACPI_WALK_STATE         *WalkState,
443     ACPI_NAMESPACE_NODE     **ReturnNode)
444 {
445     ACPI_STATUS             Status;
446     char                    *Path = Pathname;
447     char                    *ExternalPath;
448     ACPI_NAMESPACE_NODE     *PrefixNode;
449     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
450     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
451     UINT32                  NumSegments;
452     UINT32                  NumCarats;
453     ACPI_NAME               SimpleName;
454     ACPI_OBJECT_TYPE        TypeToCheckFor;
455     ACPI_OBJECT_TYPE        ThisSearchType;
456     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
457     UINT32                  LocalFlags;
458     ACPI_INTERPRETER_MODE   LocalInterpreterMode;
459 
460 
461     ACPI_FUNCTION_TRACE (NsLookup);
462 
463 
464     if (!ReturnNode)
465     {
466         return_ACPI_STATUS (AE_BAD_PARAMETER);
467     }
468 
469     LocalFlags = Flags &
470         ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
471           ACPI_NS_SEARCH_PARENT);
472     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
473     AcpiGbl_NsLookupCount++;
474 
475     if (!AcpiGbl_RootNode)
476     {
477         return_ACPI_STATUS (AE_NO_NAMESPACE);
478     }
479 
480     /* Get the prefix scope. A null scope means use the root scope */
481 
482     if ((!ScopeInfo) ||
483         (!ScopeInfo->Scope.Node))
484     {
485         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
486             "Null scope prefix, using root node (%p)\n",
487             AcpiGbl_RootNode));
488 
489         PrefixNode = AcpiGbl_RootNode;
490     }
491     else
492     {
493         PrefixNode = ScopeInfo->Scope.Node;
494         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
495         {
496             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
497                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
498             return_ACPI_STATUS (AE_AML_INTERNAL);
499         }
500 
501         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
502         {
503             /*
504              * This node might not be a actual "scope" node (such as a
505              * Device/Method, etc.)  It could be a Package or other object
506              * node. Backup up the tree to find the containing scope node.
507              */
508             while (!AcpiNsOpensScope (PrefixNode->Type) &&
509                     PrefixNode->Type != ACPI_TYPE_ANY)
510             {
511                 PrefixNode = PrefixNode->Parent;
512             }
513         }
514     }
515 
516     /* Save type. TBD: may be no longer necessary */
517 
518     TypeToCheckFor = Type;
519 
520     /*
521      * Begin examination of the actual pathname
522      */
523     if (!Pathname)
524     {
525         /* A Null NamePath is allowed and refers to the root */
526 
527         NumSegments = 0;
528         ThisNode = AcpiGbl_RootNode;
529         Path = "";
530 
531         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
532             "Null Pathname (Zero segments), Flags=%X\n", Flags));
533     }
534     else
535     {
536         /*
537          * Name pointer is valid (and must be in internal name format)
538          *
539          * Check for scope prefixes:
540          *
541          * As represented in the AML stream, a namepath consists of an
542          * optional scope prefix followed by a name segment part.
543          *
544          * If present, the scope prefix is either a Root Prefix (in
545          * which case the name is fully qualified), or one or more
546          * Parent Prefixes (in which case the name's scope is relative
547          * to the current scope).
548          */
549         if (*Path == (UINT8) AML_ROOT_PREFIX)
550         {
551             /* Pathname is fully qualified, start from the root */
552 
553             ThisNode = AcpiGbl_RootNode;
554             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
555 
556             /* Point to name segment part */
557 
558             Path++;
559 
560             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
561                 "Path is absolute from root [%p]\n", ThisNode));
562         }
563         else
564         {
565             /* Pathname is relative to current scope, start there */
566 
567             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
568                 "Searching relative to prefix scope [%4.4s] (%p)\n",
569                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
570 
571             /*
572              * Handle multiple Parent Prefixes (carat) by just getting
573              * the parent node for each prefix instance.
574              */
575             ThisNode = PrefixNode;
576             NumCarats = 0;
577             while (*Path == (UINT8) AML_PARENT_PREFIX)
578             {
579                 /* Name is fully qualified, no search rules apply */
580 
581                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
582 
583                 /*
584                  * Point past this prefix to the name segment
585                  * part or the next Parent Prefix
586                  */
587                 Path++;
588 
589                 /* Backup to the parent node */
590 
591                 NumCarats++;
592                 ThisNode = ThisNode->Parent;
593                 if (!ThisNode)
594                 {
595                     /*
596                      * Current scope has no parent scope. Externalize
597                      * the internal path for error message.
598                      */
599                     Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, Pathname,
600                         NULL, &ExternalPath);
601                     if (ACPI_SUCCESS (Status))
602                     {
603                         ACPI_ERROR ((AE_INFO,
604                             "%s: Path has too many parent prefixes (^)",
605                             ExternalPath));
606 
607                         ACPI_FREE (ExternalPath);
608                     }
609 
610                     return_ACPI_STATUS (AE_NOT_FOUND);
611                 }
612             }
613 
614             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
615             {
616                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
617                     "Search scope is [%4.4s], path has %u carat(s)\n",
618                     AcpiUtGetNodeName (ThisNode), NumCarats));
619             }
620         }
621 
622         /*
623          * Determine the number of ACPI name segments in this pathname.
624          *
625          * The segment part consists of either:
626          *  - A Null name segment (0)
627          *  - A DualNamePrefix followed by two 4-byte name segments
628          *  - A MultiNamePrefix followed by a byte indicating the
629          *      number of segments and the segments themselves.
630          *  - A single 4-byte name segment
631          *
632          * Examine the name prefix opcode, if any, to determine the number of
633          * segments.
634          */
635         switch (*Path)
636         {
637         case 0:
638             /*
639              * Null name after a root or parent prefixes. We already
640              * have the correct target node and there are no name segments.
641              */
642             NumSegments  = 0;
643             Type = ThisNode->Type;
644 
645             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
646                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
647                 Flags));
648             break;
649 
650         case AML_DUAL_NAME_PREFIX:
651 
652             /* More than one NameSeg, search rules do not apply */
653 
654             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
655 
656             /* Two segments, point to first name segment */
657 
658             NumSegments = 2;
659             Path++;
660 
661             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
662                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
663             break;
664 
665         case AML_MULTI_NAME_PREFIX:
666 
667             /* More than one NameSeg, search rules do not apply */
668 
669             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
670 
671             /* Extract segment count, point to first name segment */
672 
673             Path++;
674             NumSegments = (UINT32) (UINT8) *Path;
675             Path++;
676 
677             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
678                 "Multi Pathname (%u Segments, Flags=%X)\n",
679                 NumSegments, Flags));
680             break;
681 
682         default:
683             /*
684              * Not a Null name, no Dual or Multi prefix, hence there is
685              * only one name segment and Pathname is already pointing to it.
686              */
687             NumSegments = 1;
688 
689             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
690                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
691             break;
692         }
693 
694         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
695     }
696 
697 
698     /*
699      * Search namespace for each segment of the name. Loop through and
700      * verify (or add to the namespace) each name segment.
701      *
702      * The object type is significant only at the last name
703      * segment. (We don't care about the types along the path, only
704      * the type of the final target object.)
705      */
706     ThisSearchType = ACPI_TYPE_ANY;
707     CurrentNode = ThisNode;
708 
709     while (NumSegments && CurrentNode)
710     {
711         NumSegments--;
712         if (!NumSegments)
713         {
714             /* This is the last segment, enable typechecking */
715 
716             ThisSearchType = Type;
717 
718             /*
719              * Only allow automatic parent search (search rules) if the caller
720              * requested it AND we have a single, non-fully-qualified NameSeg
721              */
722             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
723                 (Flags & ACPI_NS_SEARCH_PARENT))
724             {
725                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
726             }
727 
728             /* Set error flag according to caller */
729 
730             if (Flags & ACPI_NS_ERROR_IF_FOUND)
731             {
732                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
733             }
734 
735             /* Set override flag according to caller */
736 
737             if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
738             {
739                 LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
740             }
741         }
742 
743         /* Handle opcodes that create a new NameSeg via a full NamePath */
744 
745         LocalInterpreterMode = InterpreterMode;
746         if ((Flags & ACPI_NS_PREFIX_MUST_EXIST) && (NumSegments > 0))
747         {
748             /* Every element of the path must exist (except for the final NameSeg) */
749 
750             LocalInterpreterMode = ACPI_IMODE_EXECUTE;
751         }
752 
753         /* Extract one ACPI name from the front of the pathname */
754 
755         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
756 
757         /* Try to find the single (4 character) ACPI name */
758 
759         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
760             LocalInterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
761         if (ACPI_FAILURE (Status))
762         {
763             if (Status == AE_NOT_FOUND)
764             {
765 #if !defined ACPI_ASL_COMPILER /* Note: iASL reports this error by itself, not needed here */
766                 if (Flags & ACPI_NS_PREFIX_MUST_EXIST)
767                 {
768                     AcpiOsPrintf (ACPI_MSG_BIOS_ERROR
769                         "Object does not exist: %4.4s\n", (char *) &SimpleName);
770                 }
771 #endif
772                 /* Name not found in ACPI namespace */
773 
774                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
775                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
776                     (char *) &SimpleName, (char *) &CurrentNode->Name,
777                     CurrentNode));
778             }
779 
780 #ifdef ACPI_EXEC_APP
781             if ((Status == AE_ALREADY_EXISTS) &&
782                 (ThisNode->Flags & ANOBJ_NODE_EARLY_INIT))
783             {
784                 ThisNode->Flags &= ~ANOBJ_NODE_EARLY_INIT;
785                 Status = AE_OK;
786             }
787 #endif
788 
789 #ifdef ACPI_ASL_COMPILER
790             /*
791              * If this ACPI name already exists within the namespace as an
792              * external declaration, then mark the external as a conflicting
793              * declaration and proceed to process the current node as if it did
794              * not exist in the namespace. If this node is not processed as
795              * normal, then it could cause improper namespace resolution
796              * by failing to open a new scope.
797              */
798             if (AcpiGbl_DisasmFlag &&
799                 (Status == AE_ALREADY_EXISTS) &&
800                 ((ThisNode->Flags & ANOBJ_IS_EXTERNAL) ||
801                     (WalkState && WalkState->Opcode == AML_EXTERNAL_OP)))
802             {
803                 ThisNode->Flags &= ~ANOBJ_IS_EXTERNAL;
804                 ThisNode->Type = (UINT8)ThisSearchType;
805                 if (WalkState->Opcode != AML_EXTERNAL_OP)
806                 {
807                     AcpiDmMarkExternalConflict (ThisNode);
808                 }
809                 break;
810             }
811 #endif
812 
813             *ReturnNode = ThisNode;
814             return_ACPI_STATUS (Status);
815         }
816 
817         /* More segments to follow? */
818 
819         if (NumSegments > 0)
820         {
821             /*
822              * If we have an alias to an object that opens a scope (such as a
823              * device or processor), we need to dereference the alias here so
824              * that we can access any children of the original node (via the
825              * remaining segments).
826              */
827             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
828             {
829                 if (!ThisNode->Object)
830                 {
831                     return_ACPI_STATUS (AE_NOT_EXIST);
832                 }
833 
834                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
835                         ThisNode->Object)->Type))
836                 {
837                     ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
838                 }
839             }
840         }
841 
842         /* Special handling for the last segment (NumSegments == 0) */
843 
844         else
845         {
846             /*
847              * Sanity typecheck of the target object:
848              *
849              * If 1) This is the last segment (NumSegments == 0)
850              *    2) And we are looking for a specific type
851              *       (Not checking for TYPE_ANY)
852              *    3) Which is not an alias
853              *    4) Which is not a local type (TYPE_SCOPE)
854              *    5) And the type of target object is known (not TYPE_ANY)
855              *    6) And target object does not match what we are looking for
856              *
857              * Then we have a type mismatch. Just warn and ignore it.
858              */
859             if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
860                 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
861                 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
862                 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
863                 (ThisNode->Type != ACPI_TYPE_ANY)                   &&
864                 (ThisNode->Type != TypeToCheckFor))
865             {
866                 /* Complain about a type mismatch */
867 
868                 ACPI_WARNING ((AE_INFO,
869                     "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
870                     ACPI_CAST_PTR (char, &SimpleName),
871                     AcpiUtGetTypeName (ThisNode->Type),
872                     AcpiUtGetTypeName (TypeToCheckFor)));
873             }
874 
875             /*
876              * If this is the last name segment and we are not looking for a
877              * specific type, but the type of found object is known, use that
878              * type to (later) see if it opens a scope.
879              */
880             if (Type == ACPI_TYPE_ANY)
881             {
882                 Type = ThisNode->Type;
883             }
884         }
885 
886         /* Point to next name segment and make this node current */
887 
888         Path += ACPI_NAMESEG_SIZE;
889         CurrentNode = ThisNode;
890     }
891 
892     /* Always check if we need to open a new scope */
893 
894     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
895     {
896         /*
897          * If entry is a type which opens a scope, push the new scope on the
898          * scope stack.
899          */
900         if (AcpiNsOpensScope (Type))
901         {
902             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
903             if (ACPI_FAILURE (Status))
904             {
905                 return_ACPI_STATUS (Status);
906             }
907         }
908     }
909 
910 #ifdef ACPI_EXEC_APP
911     if (Flags & ACPI_NS_EARLY_INIT)
912     {
913         ThisNode->Flags |= ANOBJ_NODE_EARLY_INIT;
914     }
915 #endif
916 
917     *ReturnNode = ThisNode;
918     return_ACPI_STATUS (AE_OK);
919 }
920