drivers/bus/acpi/acpica/namespace/nsaccess.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2018, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include "acpi.h"
  45 #include "accommon.h"
  46 #include "amlcode.h"
  47 #include "acnamesp.h"
  48 #include "acdispat.h"
  49
  50 #ifdef ACPI_ASL_COMPILER
  51     #include "acdisasm.h"
  52 #endif
  53
  54 #define _COMPONENT          ACPI_NAMESPACE
  55         ACPI_MODULE_NAME    ("nsaccess")
  56
  57
  58 /*******************************************************************************
  59  *
  60  * FUNCTION:    AcpiNsRootInitialize
  61  *
  62  * PARAMETERS:  None
  63  *
  64  * RETURN:      Status
  65  *
  66  * DESCRIPTION: Allocate and initialize the default root named objects
  67  *
  68  * MUTEX:       Locks namespace for entire execution
  69  *
  70  ******************************************************************************/
  71
  72 ACPI_STATUS
  73 AcpiNsRootInitialize (
  74     void)
  75 {
  76     ACPI_STATUS                 Status;
  77     const ACPI_PREDEFINED_NAMES *InitVal = NULL;
  78     ACPI_NAMESPACE_NODE         *NewNode;
  79     ACPI_OPERAND_OBJECT         *ObjDesc;
  80     ACPI_STRING                 Val = NULL;
  81
  82
  83     ACPI_FUNCTION_TRACE (NsRootInitialize);
  84
  85
  86     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
  87     if (ACPI_FAILURE (Status))
  88     {
  89         return_ACPI_STATUS (Status);
  90     }
  91
  92     /*
  93      * The global root ptr is initially NULL, so a non-NULL value indicates
  94      * that AcpiNsRootInitialize() has already been called; just return.
  95      */
  96     if (AcpiGbl_RootNode)
  97     {
  98         Status = AE_OK;
  99         goto UnlockAndExit;
 100     }
 101
 102     /*
 103      * Tell the rest of the subsystem that the root is initialized
 104      * (This is OK because the namespace is locked)
 105      */
 106     AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
 107
 108     /* Enter the pre-defined names in the name table */
 109
 110     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
 111         "Entering predefined entries into namespace\n"));
 112
 113     for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
 114     {
 115         /* _OSI is optional for now, will be permanent later */
 116
 117         if (!strcmp (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
 118         {
 119             continue;
 120         }
 121
 122         Status = AcpiNsLookup (NULL, ACPI_CAST_PTR (char, InitVal->Name),
 123             InitVal->Type, ACPI_IMODE_LOAD_PASS2, ACPI_NS_NO_UPSEARCH,
 124             NULL, &NewNode);
 125         if (ACPI_FAILURE (Status))
 126         {
 127             ACPI_EXCEPTION ((AE_INFO, Status,
 128                 "Could not create predefined name %s",
 129                 InitVal->Name));
 130             continue;
 131         }
 132
 133         /*
 134          * Name entered successfully. If entry in PreDefinedNames[] specifies
 135          * an initial value, create the initial value.
 136          */
 137         if (InitVal->Val)
 138         {
 139             Status = AcpiOsPredefinedOverride (InitVal, &Val);
 140             if (ACPI_FAILURE (Status))
 141             {
 142                 ACPI_ERROR ((AE_INFO,
 143                     "Could not override predefined %s",
 144                     InitVal->Name));
 145             }
 146
 147             if (!Val)
 148             {
 149                 Val = InitVal->Val;
 150             }
 151
 152             /*
 153              * Entry requests an initial value, allocate a
 154              * descriptor for it.
 155              */
 156             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
 157             if (!ObjDesc)
 158             {
 159                 Status = AE_NO_MEMORY;
 160                 goto UnlockAndExit;
 161             }
 162
 163             /*
 164              * Convert value string from table entry to
 165              * internal representation. Only types actually
 166              * used for initial values are implemented here.
 167              */
 168             switch (InitVal->Type)
 169             {
 170             case ACPI_TYPE_METHOD:
 171
 172                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
 173                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
 174
 175 #if defined (ACPI_ASL_COMPILER)
 176
 177                 /* Save the parameter count for the iASL compiler */
 178
 179                 NewNode->Value = ObjDesc->Method.ParamCount;
 180 #else
 181                 /* Mark this as a very SPECIAL method */
 182
 183                 ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
 184                 ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
 185 #endif
 186                 break;
 187
 188             case ACPI_TYPE_INTEGER:
 189
 190                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
 191                 break;
 192
 193             case ACPI_TYPE_STRING:
 194
 195                 /* Build an object around the static string */
 196
 197                 ObjDesc->String.Length = (UINT32) strlen (Val);
 198                 ObjDesc->String.Pointer = Val;
 199                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
 200                 break;
 201
 202             case ACPI_TYPE_MUTEX:
 203
 204                 ObjDesc->Mutex.Node = NewNode;
 205                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
 206
 207                 /* Create a mutex */
 208
 209                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
 210                 if (ACPI_FAILURE (Status))
 211                 {
 212                     AcpiUtRemoveReference (ObjDesc);
 213                     goto UnlockAndExit;
 214                 }
 215
 216                 /* Special case for ACPI Global Lock */
 217
 218                 if (strcmp (InitVal->Name, "_GL_") == 0)
 219                 {
 220                     AcpiGbl_GlobalLockMutex = ObjDesc;
 221
 222                     /* Create additional counting semaphore for global lock */
 223
 224                     Status = AcpiOsCreateSemaphore (
 225                         1, 0, &AcpiGbl_GlobalLockSemaphore);
 226                     if (ACPI_FAILURE (Status))
 227                     {
 228                         AcpiUtRemoveReference (ObjDesc);
 229                         goto UnlockAndExit;
 230                     }
 231                 }
 232                 break;
 233
 234             default:
 235
 236                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
 237                     InitVal->Type));
 238                 AcpiUtRemoveReference (ObjDesc);
 239                 ObjDesc = NULL;
 240                 continue;
 241             }
 242
 243             /* Store pointer to value descriptor in the Node */
 244
 245             Status = AcpiNsAttachObject (NewNode, ObjDesc,
 246                 ObjDesc->Common.Type);
 247
 248             /* Remove local reference to the object */
 249
 250             AcpiUtRemoveReference (ObjDesc);
 251         }
 252     }
 253
 254
 255 UnlockAndExit:
 256     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
 257
 258     /* Save a handle to "_GPE", it is always present */
 259
 260     if (ACPI_SUCCESS (Status))
 261     {
 262         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
 263             &AcpiGbl_FadtGpeDevice);
 264     }
 265
 266     return_ACPI_STATUS (Status);
 267 }
 268
 269
 270 /*******************************************************************************
 271  *
 272  * FUNCTION:    AcpiNsLookup
 273  *
 274  * PARAMETERS:  ScopeInfo       - Current scope info block
 275  *              Pathname        - Search pathname, in internal format
 276  *                                (as represented in the AML stream)
 277  *              Type            - Type associated with name
 278  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
 279  *              Flags           - Flags describing the search restrictions
 280  *              WalkState       - Current state of the walk
 281  *              ReturnNode      - Where the Node is placed (if found
 282  *                                or created successfully)
 283  *
 284  * RETURN:      Status
 285  *
 286  * DESCRIPTION: Find or enter the passed name in the name space.
 287  *              Log an error if name not found in Exec mode.
 288  *
 289  * MUTEX:       Assumes namespace is locked.
 290  *
 291  ******************************************************************************/
 292
 293 ACPI_STATUS
 294 AcpiNsLookup (
 295     ACPI_GENERIC_STATE      *ScopeInfo,
 296     char                    *Pathname,
 297     ACPI_OBJECT_TYPE        Type,
 298     ACPI_INTERPRETER_MODE   InterpreterMode,
 299     UINT32                  Flags,
 300     ACPI_WALK_STATE         *WalkState,
 301     ACPI_NAMESPACE_NODE     **ReturnNode)
 302 {
 303     ACPI_STATUS             Status;
 304     char                    *Path = Pathname;
 305     char                    *ExternalPath;
 306     ACPI_NAMESPACE_NODE     *PrefixNode;
 307     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
 308     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
 309     UINT32                  NumSegments;
 310     UINT32                  NumCarats;
 311     ACPI_NAME               SimpleName;
 312     ACPI_OBJECT_TYPE        TypeToCheckFor;
 313     ACPI_OBJECT_TYPE        ThisSearchType;
 314     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
 315     UINT32                  LocalFlags;
 316
 317
 318     ACPI_FUNCTION_TRACE (NsLookup);
 319
 320
 321     if (!ReturnNode)
 322     {
 323         return_ACPI_STATUS (AE_BAD_PARAMETER);
 324     }
 325
 326     LocalFlags = Flags &
 327         ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
 328           ACPI_NS_SEARCH_PARENT);
 329     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
 330     AcpiGbl_NsLookupCount++;
 331
 332     if (!AcpiGbl_RootNode)
 333     {
 334         return_ACPI_STATUS (AE_NO_NAMESPACE);
 335     }
 336
 337     /* Get the prefix scope. A null scope means use the root scope */
 338
 339     if ((!ScopeInfo) ||
 340         (!ScopeInfo->Scope.Node))
 341     {
 342         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 343             "Null scope prefix, using root node (%p)\n",
 344             AcpiGbl_RootNode));
 345
 346         PrefixNode = AcpiGbl_RootNode;
 347     }
 348     else
 349     {
 350         PrefixNode = ScopeInfo->Scope.Node;
 351         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
 352         {
 353             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
 354                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
 355             return_ACPI_STATUS (AE_AML_INTERNAL);
 356         }
 357
 358         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
 359         {
 360             /*
 361              * This node might not be a actual "scope" node (such as a
 362              * Device/Method, etc.)  It could be a Package or other object
 363              * node. Backup up the tree to find the containing scope node.
 364              */
 365             while (!AcpiNsOpensScope (PrefixNode->Type) &&
 366                     PrefixNode->Type != ACPI_TYPE_ANY)
 367             {
 368                 PrefixNode = PrefixNode->Parent;
 369             }
 370         }
 371     }
 372
 373     /* Save type. TBD: may be no longer necessary */
 374
 375     TypeToCheckFor = Type;
 376
 377     /*
 378      * Begin examination of the actual pathname
 379      */
 380     if (!Pathname)
 381     {
 382         /* A Null NamePath is allowed and refers to the root */
 383
 384         NumSegments = 0;
 385         ThisNode = AcpiGbl_RootNode;
 386         Path = "";
 387
 388         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 389             "Null Pathname (Zero segments), Flags=%X\n", Flags));
 390     }
 391     else
 392     {
 393         /*
 394          * Name pointer is valid (and must be in internal name format)
 395          *
 396          * Check for scope prefixes:
 397          *
 398          * As represented in the AML stream, a namepath consists of an
 399          * optional scope prefix followed by a name segment part.
 400          *
 401          * If present, the scope prefix is either a Root Prefix (in
 402          * which case the name is fully qualified), or one or more
 403          * Parent Prefixes (in which case the name's scope is relative
 404          * to the current scope).
 405          */
 406         if (*Path == (UINT8) AML_ROOT_PREFIX)
 407         {
 408             /* Pathname is fully qualified, start from the root */
 409
 410             ThisNode = AcpiGbl_RootNode;
 411             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
 412
 413             /* Point to name segment part */
 414
 415             Path++;
 416
 417             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 418                 "Path is absolute from root [%p]\n", ThisNode));
 419         }
 420         else
 421         {
 422             /* Pathname is relative to current scope, start there */
 423
 424             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 425                 "Searching relative to prefix scope [%4.4s] (%p)\n",
 426                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
 427
 428             /*
 429              * Handle multiple Parent Prefixes (carat) by just getting
 430              * the parent node for each prefix instance.
 431              */
 432             ThisNode = PrefixNode;
 433             NumCarats = 0;
 434             while (*Path == (UINT8) AML_PARENT_PREFIX)
 435             {
 436                 /* Name is fully qualified, no search rules apply */
 437
 438                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
 439
 440                 /*
 441                  * Point past this prefix to the name segment
 442                  * part or the next Parent Prefix
 443                  */
 444                 Path++;
 445
 446                 /* Backup to the parent node */
 447
 448                 NumCarats++;
 449                 ThisNode = ThisNode->Parent;
 450                 if (!ThisNode)
 451                 {
 452                     /*
 453                      * Current scope has no parent scope. Externalize
 454                      * the internal path for error message.
 455                      */
 456                     Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, Pathname,
 457                         NULL, &ExternalPath);
 458                     if (ACPI_SUCCESS (Status))
 459                     {
 460                         ACPI_ERROR ((AE_INFO,
 461                             "%s: Path has too many parent prefixes (^)",
 462                             ExternalPath));
 463
 464                         ACPI_FREE (ExternalPath);
 465                     }
 466
 467                     return_ACPI_STATUS (AE_NOT_FOUND);
 468                 }
 469             }
 470
 471             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
 472             {
 473                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 474                     "Search scope is [%4.4s], path has %u carat(s)\n",
 475                     AcpiUtGetNodeName (ThisNode), NumCarats));
 476             }
 477         }
 478
 479         /*
 480          * Determine the number of ACPI name segments in this pathname.
 481          *
 482          * The segment part consists of either:
 483          *  - A Null name segment (0)
 484          *  - A DualNamePrefix followed by two 4-byte name segments
 485          *  - A MultiNamePrefix followed by a byte indicating the
 486          *      number of segments and the segments themselves.
 487          *  - A single 4-byte name segment
 488          *
 489          * Examine the name prefix opcode, if any, to determine the number of
 490          * segments.
 491          */
 492         switch (*Path)
 493         {
 494         case 0:
 495             /*
 496              * Null name after a root or parent prefixes. We already
 497              * have the correct target node and there are no name segments.
 498              */
 499             NumSegments  = 0;
 500             Type = ThisNode->Type;
 501
 502             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 503                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
 504                 Flags));
 505             break;
 506
 507         case AML_DUAL_NAME_PREFIX:
 508
 509             /* More than one NameSeg, search rules do not apply */
 510
 511             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
 512
 513             /* Two segments, point to first name segment */
 514
 515             NumSegments = 2;
 516             Path++;
 517
 518             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 519                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
 520             break;
 521
 522         case AML_MULTI_NAME_PREFIX:
 523
 524             /* More than one NameSeg, search rules do not apply */
 525
 526             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
 527
 528             /* Extract segment count, point to first name segment */
 529
 530             Path++;
 531             NumSegments = (UINT32) (UINT8) *Path;
 532             Path++;
 533
 534             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 535                 "Multi Pathname (%u Segments, Flags=%X)\n",
 536                 NumSegments, Flags));
 537             break;
 538
 539         default:
 540             /*
 541              * Not a Null name, no Dual or Multi prefix, hence there is
 542              * only one name segment and Pathname is already pointing to it.
 543              */
 544             NumSegments = 1;
 545
 546             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 547                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
 548             break;
 549         }
 550
 551         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
 552     }
 553
 554
 555     /*
 556      * Search namespace for each segment of the name. Loop through and
 557      * verify (or add to the namespace) each name segment.
 558      *
 559      * The object type is significant only at the last name
 560      * segment. (We don't care about the types along the path, only
 561      * the type of the final target object.)
 562      */
 563     ThisSearchType = ACPI_TYPE_ANY;
 564     CurrentNode = ThisNode;
 565     while (NumSegments && CurrentNode)
 566     {
 567         NumSegments--;
 568         if (!NumSegments)
 569         {
 570             /* This is the last segment, enable typechecking */
 571
 572             ThisSearchType = Type;
 573
 574             /*
 575              * Only allow automatic parent search (search rules) if the caller
 576              * requested it AND we have a single, non-fully-qualified NameSeg
 577              */
 578             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
 579                 (Flags & ACPI_NS_SEARCH_PARENT))
 580             {
 581                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
 582             }
 583
 584             /* Set error flag according to caller */
 585
 586             if (Flags & ACPI_NS_ERROR_IF_FOUND)
 587             {
 588                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
 589             }
 590
 591             /* Set override flag according to caller */
 592
 593             if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
 594             {
 595                 LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
 596             }
 597         }
 598
 599         /* Extract one ACPI name from the front of the pathname */
 600
 601         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
 602
 603         /* Try to find the single (4 character) ACPI name */
 604
 605         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
 606             InterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
 607         if (ACPI_FAILURE (Status))
 608         {
 609             if (Status == AE_NOT_FOUND)
 610             {
 611                 /* Name not found in ACPI namespace */
 612
 613                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
 614                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
 615                     (char *) &SimpleName, (char *) &CurrentNode->Name,
 616                     CurrentNode));
 617             }
 618
 619 #ifdef ACPI_EXEC_APP
 620             if ((Status == AE_ALREADY_EXISTS) &&
 621                 (ThisNode->Flags & ANOBJ_NODE_EARLY_INIT))
 622             {
 623                 ThisNode->Flags &= ~ANOBJ_NODE_EARLY_INIT;
 624                 Status = AE_OK;
 625             }
 626 #endif
 627
 628 #ifdef ACPI_ASL_COMPILER
 629             /*
 630              * If this ACPI name already exists within the namespace as an
 631              * external declaration, then mark the external as a conflicting
 632              * declaration and proceed to process the current node as if it did
 633              * not exist in the namespace. If this node is not processed as
 634              * normal, then it could cause improper namespace resolution
 635              * by failing to open a new scope.
 636              */
 637             if (AcpiGbl_DisasmFlag &&
 638                 (Status == AE_ALREADY_EXISTS) &&
 639                 ((ThisNode->Flags & ANOBJ_IS_EXTERNAL) ||
 640                     (WalkState && WalkState->Opcode == AML_EXTERNAL_OP)))
 641             {
 642                 ThisNode->Flags &= ~ANOBJ_IS_EXTERNAL;
 643                 ThisNode->Type = (UINT8)ThisSearchType;
 644                 if (WalkState->Opcode != AML_EXTERNAL_OP)
 645                 {
 646                     AcpiDmMarkExternalConflict (ThisNode);
 647                 }
 648                 break;
 649             }
 650 #endif
 651
 652             *ReturnNode = ThisNode;
 653             return_ACPI_STATUS (Status);
 654         }
 655
 656         /* More segments to follow? */
 657
 658         if (NumSegments > 0)
 659         {
 660             /*
 661              * If we have an alias to an object that opens a scope (such as a
 662              * device or processor), we need to dereference the alias here so
 663              * that we can access any children of the original node (via the
 664              * remaining segments).
 665              */
 666             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
 667             {
 668                 if (!ThisNode->Object)
 669                 {
 670                     return_ACPI_STATUS (AE_NOT_EXIST);
 671                 }
 672
 673                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
 674                         ThisNode->Object)->Type))
 675                 {
 676                     ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
 677                 }
 678             }
 679         }
 680
 681         /* Special handling for the last segment (NumSegments == 0) */
 682
 683         else
 684         {
 685             /*
 686              * Sanity typecheck of the target object:
 687              *
 688              * If 1) This is the last segment (NumSegments == 0)
 689              *    2) And we are looking for a specific type
 690              *       (Not checking for TYPE_ANY)
 691              *    3) Which is not an alias
 692              *    4) Which is not a local type (TYPE_SCOPE)
 693              *    5) And the type of target object is known (not TYPE_ANY)
 694              *    6) And target object does not match what we are looking for
 695              *
 696              * Then we have a type mismatch. Just warn and ignore it.
 697              */
 698             if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
 699                 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
 700                 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
 701                 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
 702                 (ThisNode->Type != ACPI_TYPE_ANY)                   &&
 703                 (ThisNode->Type != TypeToCheckFor))
 704             {
 705                 /* Complain about a type mismatch */
 706
 707                 ACPI_WARNING ((AE_INFO,
 708                     "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
 709                     ACPI_CAST_PTR (char, &SimpleName),
 710                     AcpiUtGetTypeName (ThisNode->Type),
 711                     AcpiUtGetTypeName (TypeToCheckFor)));
 712             }
 713
 714             /*
 715              * If this is the last name segment and we are not looking for a
 716              * specific type, but the type of found object is known, use that
 717              * type to (later) see if it opens a scope.
 718              */
 719             if (Type == ACPI_TYPE_ANY)
 720             {
 721                 Type = ThisNode->Type;
 722             }
 723         }
 724
 725         /* Point to next name segment and make this node current */
 726
 727         Path += ACPI_NAME_SIZE;
 728         CurrentNode = ThisNode;
 729     }
 730
 731     /* Always check if we need to open a new scope */
 732
 733     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
 734     {
 735         /*
 736          * If entry is a type which opens a scope, push the new scope on the
 737          * scope stack.
 738          */
 739         if (AcpiNsOpensScope (Type))
 740         {
 741             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
 742             if (ACPI_FAILURE (Status))
 743             {
 744                 return_ACPI_STATUS (Status);
 745             }
 746         }
 747     }
 748
 749 #ifdef ACPI_EXEC_APP
 750     if (Flags & ACPI_NS_EARLY_INIT)
 751     {
 752         ThisNode->Flags |= ANOBJ_NODE_EARLY_INIT;
 753     }
 754 #endif
 755
 756     *ReturnNode = ThisNode;
 757     return_ACPI_STATUS (AE_OK);
 758 }