xref: /netbsd-src/sys/external/bsd/acpica/dist/compiler/aslxref.c (revision 42b9e898991e23b560315a9b1da6a36a39d4351b)
1 /******************************************************************************
2  *
3  * Module Name: aslxref - Namespace cross-reference
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2020, 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 "aslcompiler.h"
45 #include "aslcompiler.y.h"
46 #include "acparser.h"
47 #include "amlcode.h"
48 #include "acnamesp.h"
49 #include "acdispat.h"
50 
51 
52 #define _COMPONENT          ACPI_COMPILER
53         ACPI_MODULE_NAME    ("aslxref")
54 
55 /* Local prototypes */
56 
57 static ACPI_STATUS
58 XfNamespaceLocateBegin (
59     ACPI_PARSE_OBJECT       *Op,
60     UINT32                  Level,
61     void                    *Context);
62 
63 static ACPI_STATUS
64 XfNamespaceLocateEnd (
65     ACPI_PARSE_OBJECT       *Op,
66     UINT32                  Level,
67     void                    *Context);
68 
69 static BOOLEAN
70 XfValidateCrossReference (
71     ACPI_PARSE_OBJECT       *Op,
72     const ACPI_OPCODE_INFO  *OpInfo,
73     ACPI_NAMESPACE_NODE     *Node);
74 
75 static BOOLEAN
76 XfObjectExists (
77     char                    *Name);
78 
79 static ACPI_STATUS
80 XfCompareOneNamespaceObject (
81     ACPI_HANDLE             ObjHandle,
82     UINT32                  Level,
83     void                    *Context,
84     void                    **ReturnValue);
85 
86 static void
87 XfCheckFieldRange (
88     ACPI_PARSE_OBJECT       *Op,
89     UINT32                  RegionBitLength,
90     UINT32                  FieldBitOffset,
91     UINT32                  FieldBitLength,
92     UINT32                  AccessBitWidth);
93 
94 static BOOLEAN
95 XfFindCondRefOfName (
96     ACPI_NAMESPACE_NODE     *Node,
97     ACPI_PARSE_OBJECT       *Op);
98 
99 static BOOLEAN
100 XfRefIsGuardedByIfCondRefOf (
101     ACPI_NAMESPACE_NODE     *Node,
102     ACPI_PARSE_OBJECT       *Op);
103 
104 
105 /*******************************************************************************
106  *
107  * FUNCTION:    XfCrossReferenceNamespace
108  *
109  * PARAMETERS:  None
110  *
111  * RETURN:      Status
112  *
113  * DESCRIPTION: Perform a cross reference check of the parse tree against the
114  *              namespace. Every named referenced within the parse tree
115  *              should be get resolved with a namespace lookup. If not, the
116  *              original reference in the ASL code is invalid -- i.e., refers
117  *              to a non-existent object.
118  *
119  * NOTE:  The ASL "External" operator causes the name to be inserted into the
120  *        namespace so that references to the external name will be resolved
121  *        correctly here.
122  *
123  ******************************************************************************/
124 
125 ACPI_STATUS
126 XfCrossReferenceNamespace (
127     void)
128 {
129     ACPI_WALK_STATE         *WalkState;
130 
131 
132     /*
133      * Create a new walk state for use when looking up names
134      * within the namespace (Passed as context to the callbacks)
135      */
136     WalkState = AcpiDsCreateWalkState (0, NULL, NULL, NULL);
137     if (!WalkState)
138     {
139         return (AE_NO_MEMORY);
140     }
141 
142     /* Walk the entire parse tree */
143 
144     TrWalkParseTree (AslGbl_ParseTreeRoot, ASL_WALK_VISIT_TWICE,
145         XfNamespaceLocateBegin, XfNamespaceLocateEnd, WalkState);
146 
147     ACPI_FREE (WalkState);
148     return (AE_OK);
149 }
150 
151 
152 /*******************************************************************************
153  *
154  * FUNCTION:    XfObjectExists
155  *
156  * PARAMETERS:  Name            - 4 char ACPI name
157  *
158  * RETURN:      TRUE if name exists in namespace
159  *
160  * DESCRIPTION: Walk the namespace to find an object
161  *
162  ******************************************************************************/
163 
164 static BOOLEAN
165 XfObjectExists (
166     char                    *Name)
167 {
168     ACPI_STATUS             Status;
169 
170 
171     /* Walk entire namespace from the supplied root */
172 
173     Status = AcpiNsWalkNamespace (ACPI_TYPE_ANY, ACPI_ROOT_OBJECT,
174         ACPI_UINT32_MAX, FALSE, XfCompareOneNamespaceObject, NULL,
175         Name, NULL);
176     if (Status == AE_CTRL_TRUE)
177     {
178         /* At least one instance of the name was found */
179 
180         return (TRUE);
181     }
182 
183     return (FALSE);
184 }
185 
186 
187 /*******************************************************************************
188  *
189  * FUNCTION:    XfCompareOneNamespaceObject
190  *
191  * PARAMETERS:  ACPI_WALK_CALLBACK
192  *
193  * RETURN:      Status
194  *
195  * DESCRIPTION: Compare name of one object.
196  *
197  ******************************************************************************/
198 
199 static ACPI_STATUS
200 XfCompareOneNamespaceObject (
201     ACPI_HANDLE             ObjHandle,
202     UINT32                  Level,
203     void                    *Context,
204     void                    **ReturnValue)
205 {
206     ACPI_NAMESPACE_NODE     *Node = (ACPI_NAMESPACE_NODE *) ObjHandle;
207 
208 
209     /* Simply check the name */
210 
211     if (*((UINT32 *) (Context)) == Node->Name.Integer)
212     {
213         /* Abort walk if we found one instance */
214 
215         return (AE_CTRL_TRUE);
216     }
217 
218     return (AE_OK);
219 }
220 
221 
222 /*******************************************************************************
223  *
224  * FUNCTION:    XfCheckFieldRange
225  *
226  * PARAMETERS:  RegionBitLength     - Length of entire parent region
227  *              FieldBitOffset      - Start of the field unit (within region)
228  *              FieldBitLength      - Entire length of field unit
229  *              AccessBitWidth      - Access width of the field unit
230  *
231  * RETURN:      None
232  *
233  * DESCRIPTION: Check one field unit to make sure it fits in the parent
234  *              op region.
235  *
236  * Note: AccessBitWidth must be either 8,16,32, or 64
237  *
238  ******************************************************************************/
239 
240 static void
241 XfCheckFieldRange (
242     ACPI_PARSE_OBJECT       *Op,
243     UINT32                  RegionBitLength,
244     UINT32                  FieldBitOffset,
245     UINT32                  FieldBitLength,
246     UINT32                  AccessBitWidth)
247 {
248     UINT32                  FieldEndBitOffset;
249 
250 
251     /*
252      * Check each field unit against the region size. The entire
253      * field unit (start offset plus length) must fit within the
254      * region.
255      */
256     FieldEndBitOffset = FieldBitOffset + FieldBitLength;
257 
258     if (FieldEndBitOffset > RegionBitLength)
259     {
260         /* Field definition itself is beyond the end-of-region */
261 
262         AslError (ASL_ERROR, ASL_MSG_FIELD_UNIT_OFFSET, Op, NULL);
263         return;
264     }
265 
266     /*
267      * Now check that the field plus AccessWidth doesn't go beyond
268      * the end-of-region. Assumes AccessBitWidth is a power of 2
269      */
270     FieldEndBitOffset = ACPI_ROUND_UP (FieldEndBitOffset, AccessBitWidth);
271 
272     if (FieldEndBitOffset > RegionBitLength)
273     {
274         /* Field definition combined with the access is beyond EOR */
275 
276         AslError (ASL_ERROR, ASL_MSG_FIELD_UNIT_ACCESS_WIDTH, Op, NULL);
277     }
278 }
279 
280 
281 /*******************************************************************************
282  *
283  * FUNCTION:    XfNamespaceLocateBegin
284  *
285  * PARAMETERS:  ASL_WALK_CALLBACK
286  *
287  * RETURN:      Status
288  *
289  * DESCRIPTION: Descending callback used during cross-reference. For named
290  *              object references, attempt to locate the name in the
291  *              namespace.
292  *
293  * NOTE: ASL references to named fields within resource descriptors are
294  *       resolved to integer values here. Therefore, this step is an
295  *       important part of the code generation. We don't know that the
296  *       name refers to a resource descriptor until now.
297  *
298  ******************************************************************************/
299 
300 static ACPI_STATUS
301 XfNamespaceLocateBegin (
302     ACPI_PARSE_OBJECT       *Op,
303     UINT32                  Level,
304     void                    *Context)
305 {
306     ACPI_WALK_STATE         *WalkState = (ACPI_WALK_STATE *) Context;
307     ACPI_NAMESPACE_NODE     *Node;
308     ACPI_STATUS             Status;
309     ACPI_OBJECT_TYPE        ObjectType;
310     char                    *Path;
311     UINT8                   PassedArgs;
312     ACPI_PARSE_OBJECT       *NextOp;
313     ACPI_PARSE_OBJECT       *OwningOp;
314     ACPI_PARSE_OBJECT       *SpaceIdOp;
315     UINT32                  MinimumLength;
316     UINT32                  Offset;
317     UINT32                  FieldBitLength;
318     UINT32                  TagBitLength;
319     UINT8                   Message = 0;
320     const ACPI_OPCODE_INFO  *OpInfo;
321     UINT32                  Flags;
322     ASL_METHOD_LOCAL        *MethodLocals = NULL;
323     ASL_METHOD_LOCAL        *MethodArgs = NULL;
324     int                     RegisterNumber;
325     UINT32                  i;
326     ACPI_NAMESPACE_NODE     *DeclarationParentMethod;
327     ACPI_PARSE_OBJECT       *ReferenceParentMethod;
328 
329 
330     ACPI_FUNCTION_TRACE_PTR (XfNamespaceLocateBegin, Op);
331 
332 
333     if ((Op->Asl.AmlOpcode == AML_METHOD_OP) && Op->Asl.Node)
334     {
335         Node = Op->Asl.Node;
336 
337         /* Support for method LocalX/ArgX analysis */
338 
339         if (!Node->MethodLocals)
340         {
341             /* Create local/arg info blocks */
342 
343             MethodLocals = UtLocalCalloc (
344                 sizeof (ASL_METHOD_LOCAL) * ACPI_METHOD_NUM_LOCALS);
345             Node->MethodLocals = MethodLocals;
346 
347             MethodArgs = UtLocalCalloc (
348                 sizeof (ASL_METHOD_LOCAL) * ACPI_METHOD_NUM_ARGS);
349             Node->MethodArgs = MethodArgs;
350 
351             /*
352              * Get the method argument count
353              * First, get the name node
354              */
355             NextOp = Op->Asl.Child;
356 
357             /* Get the NumArguments node */
358 
359             NextOp = NextOp->Asl.Next;
360             Node->ArgCount = (UINT8)
361                 (((UINT8) NextOp->Asl.Value.Integer) & 0x07);
362 
363             /* We will track all possible ArgXs */
364 
365             for (i = 0; i < ACPI_METHOD_NUM_ARGS; i++)
366             {
367                 if (i < Node->ArgCount)
368                 {
369                     /* Real Args are always "initialized" */
370 
371                     MethodArgs[i].Flags = ASL_ARG_INITIALIZED;
372                 }
373                 else
374                 {
375                     /* Other ArgXs can be used as locals */
376 
377                     MethodArgs[i].Flags = ASL_ARG_IS_LOCAL;
378                 }
379 
380                 MethodArgs[i].Op = Op;
381             }
382         }
383     }
384 
385     /*
386      * If this node is the actual declaration of a name
387      * [such as the XXXX name in "Method (XXXX)"],
388      * we are not interested in it here. We only care about names that are
389      * references to other objects within the namespace and the parent objects
390      * of name declarations
391      */
392     if (Op->Asl.CompileFlags & OP_IS_NAME_DECLARATION)
393     {
394         return_ACPI_STATUS (AE_OK);
395     }
396 
397     OpInfo = AcpiPsGetOpcodeInfo (Op->Asl.AmlOpcode);
398 
399     /* Check method LocalX variables */
400 
401     if (OpInfo->Type == AML_TYPE_LOCAL_VARIABLE)
402     {
403         /* Find parent method Op */
404 
405         NextOp = UtGetParentMethodOp (Op);
406         if (!NextOp)
407         {
408             return_ACPI_STATUS (AE_OK);
409         }
410 
411         /* Get method node */
412 
413         Node = NextOp->Asl.Node;
414 
415         RegisterNumber = Op->Asl.AmlOpcode & 0x0007; /* 0x60 through 0x67 */
416         MethodLocals = Node->MethodLocals;
417 
418         if (Op->Asl.CompileFlags & OP_IS_TARGET)
419         {
420             /* Local is being initialized */
421 
422             MethodLocals[RegisterNumber].Flags |= ASL_LOCAL_INITIALIZED;
423             MethodLocals[RegisterNumber].Op = Op;
424 
425             return_ACPI_STATUS (AE_OK);
426         }
427 
428         /* Mark this Local as referenced */
429 
430         MethodLocals[RegisterNumber].Flags |= ASL_LOCAL_REFERENCED;
431         MethodLocals[RegisterNumber].Op = Op;
432 
433         return_ACPI_STATUS (AE_OK);
434     }
435 
436     /* Check method ArgX variables */
437 
438     if (OpInfo->Type == AML_TYPE_METHOD_ARGUMENT)
439     {
440         /* Find parent method Op */
441 
442         NextOp = UtGetParentMethodOp (Op);
443         if (!NextOp)
444         {
445             return_ACPI_STATUS (AE_OK);
446         }
447 
448         /* Get method node */
449 
450         Node = NextOp->Asl.Node;
451 
452         /* Get Arg # */
453 
454         RegisterNumber = Op->Asl.AmlOpcode - AML_ARG0; /* 0x68 through 0x6F */
455         MethodArgs = Node->MethodArgs;
456 
457         /* Mark this Arg as referenced */
458 
459         MethodArgs[RegisterNumber].Flags |= ASL_ARG_REFERENCED;
460         MethodArgs[RegisterNumber].Op = Op;
461 
462         if (Op->Asl.CompileFlags & OP_IS_TARGET)
463         {
464             /* Arg is being initialized */
465 
466             MethodArgs[RegisterNumber].Flags |= ASL_ARG_INITIALIZED;
467         }
468 
469         return_ACPI_STATUS (AE_OK);
470     }
471 
472     /*
473      * After method ArgX and LocalX, we are only interested in opcodes
474      * that have an associated name
475      */
476     if ((!(OpInfo->Flags & AML_NAMED)) &&
477         (!(OpInfo->Flags & AML_CREATE)) &&
478         (Op->Asl.ParseOpcode != PARSEOP_NAMESTRING) &&
479         (Op->Asl.ParseOpcode != PARSEOP_NAMESEG)    &&
480         (Op->Asl.ParseOpcode != PARSEOP_METHODCALL) &&
481         (Op->Asl.ParseOpcode != PARSEOP_EXTERNAL))
482     {
483         return_ACPI_STATUS (AE_OK);
484     }
485 
486     /*
487      * We must enable the "search-to-root" for single NameSegs, but
488      * we have to be very careful about opening up scopes
489      */
490     Flags = ACPI_NS_SEARCH_PARENT;
491     if ((Op->Asl.ParseOpcode == PARSEOP_NAMESTRING) ||
492         (Op->Asl.ParseOpcode == PARSEOP_NAMESEG)    ||
493         (Op->Asl.ParseOpcode == PARSEOP_METHODCALL) ||
494         (Op->Asl.ParseOpcode == PARSEOP_EXTERNAL)   ||
495         (Op->Asl.ParseOpcode == PARSEOP_CONDREFOF))
496     {
497         /*
498          * These are name references, do not push the scope stack
499          * for them.
500          */
501         Flags |= ACPI_NS_DONT_OPEN_SCOPE;
502     }
503 
504     /* Get the NamePath from the appropriate place */
505 
506     if (OpInfo->Flags & AML_NAMED)
507     {
508         /* For nearly all NAMED operators, the name reference is the first child */
509 
510         Path = Op->Asl.Child->Asl.Value.String;
511         if (Op->Asl.AmlOpcode == AML_ALIAS_OP)
512         {
513             /*
514              * ALIAS is the only oddball opcode, the name declaration
515              * (alias name) is the second operand
516              */
517             Path = Op->Asl.Child->Asl.Next->Asl.Value.String;
518         }
519     }
520     else if (OpInfo->Flags & AML_CREATE)
521     {
522         /* Name must appear as the last parameter */
523 
524         NextOp = Op->Asl.Child;
525         while (!(NextOp->Asl.CompileFlags & OP_IS_NAME_DECLARATION))
526         {
527             NextOp = NextOp->Asl.Next;
528         }
529 
530         Path = NextOp->Asl.Value.String;
531     }
532     else
533     {
534         Path = Op->Asl.Value.String;
535     }
536 
537     ObjectType = AslMapNamedOpcodeToDataType (Op->Asl.AmlOpcode);
538     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
539         "Type=%s\n", AcpiUtGetTypeName (ObjectType)));
540 
541     /*
542      * Lookup the name in the namespace. Name must exist at this point, or it
543      * is an invalid reference.
544      *
545      * The namespace is also used as a lookup table for references to resource
546      * descriptors and the fields within them.
547      */
548     AslGbl_NsLookupCount++;
549 
550     Status = AcpiNsLookup (WalkState->ScopeInfo, Path, ObjectType,
551         ACPI_IMODE_EXECUTE, Flags, WalkState, &Node);
552     if (ACPI_FAILURE (Status))
553     {
554         if (Status == AE_NOT_FOUND)
555         {
556             /*
557              * We didn't find the name reference by path -- we can qualify this
558              * a little better before we print an error message
559              */
560 
561             if ((Op->Asl.Parent) &&
562                 (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_CONDREFOF))
563             {
564                 /*
565                  * One special case: CondRefOf operator - if the name doesn't
566                  * exist at this point, it means that there's no actual or
567                  * external declaration. If the name is not found, just ignore
568                  * it, the point of the operator is to determine if the name
569                  * exists at runtime. We wanted to see if this named object
570                  * exists to facilitate analysis to allow protected usage of
571                  * undeclared externals.
572                  */
573                 return_ACPI_STATUS (AE_OK);
574             }
575             else if (strlen (Path) == ACPI_NAMESEG_SIZE)
576             {
577                 /* A simple, one-segment ACPI name */
578 
579                 if (XfObjectExists (Path))
580                 {
581                     /*
582                      * There exists such a name, but we couldn't get to it
583                      * from this scope
584                      */
585                     AslError (ASL_ERROR, ASL_MSG_NOT_REACHABLE, Op,
586                         Op->Asl.ExternalName);
587                 }
588                 else
589                 {
590                     /* The name doesn't exist, period */
591 
592                     AslError (ASL_ERROR, ASL_MSG_NOT_EXIST,
593                         Op, Op->Asl.ExternalName);
594                 }
595             }
596             else
597             {
598                 /* The NamePath contains multiple NameSegs */
599 
600                 if ((OpInfo->Flags & AML_CREATE) ||
601                     (OpInfo->ObjectType == ACPI_TYPE_LOCAL_ALIAS))
602                 {
603                     /*
604                      * The new name is the last parameter. For the
605                      * CreateXXXXField and Alias operators
606                      */
607                     NextOp = Op->Asl.Child;
608                     while (!(NextOp->Asl.CompileFlags & OP_IS_NAME_DECLARATION))
609                     {
610                         NextOp = NextOp->Asl.Next;
611                     }
612 
613                     AslError (ASL_ERROR, ASL_MSG_PREFIX_NOT_EXIST, NextOp,
614                         NextOp->Asl.ExternalName);
615                 }
616                 else if (OpInfo->Flags & AML_NAMED)
617                 {
618                     /* The new name is the first parameter */
619 
620                     AslError (ASL_ERROR, ASL_MSG_PREFIX_NOT_EXIST, Op,
621                         Op->Asl.ExternalName);
622                 }
623                 else if (Path[0] == AML_ROOT_PREFIX)
624                 {
625                     /* Full namepath from root, the object does not exist */
626 
627                     AslError (ASL_ERROR, ASL_MSG_NOT_EXIST, Op,
628                         Op->Asl.ExternalName);
629                 }
630                 else
631                 {
632                     /*
633                      * Generic "not found" error. Cannot determine whether it
634                      * doesn't exist or just can't be reached. However, we
635                      * can differentiate between a NameSeg vs. NamePath.
636                      */
637                     if (strlen (Op->Asl.ExternalName) == ACPI_NAMESEG_SIZE)
638                     {
639                         AslError (ASL_ERROR, ASL_MSG_NOT_FOUND, Op,
640                             Op->Asl.ExternalName);
641                     }
642                     else
643                     {
644                         AslError (ASL_ERROR, ASL_MSG_NAMEPATH_NOT_EXIST, Op,
645                             Op->Asl.ExternalName);
646                     }
647                 }
648             }
649 
650             Status = AE_OK;
651         }
652 
653         return_ACPI_STATUS (Status);
654     }
655 
656     /* Check for an attempt to access an object in another method */
657 
658     if (!XfValidateCrossReference (Op, OpInfo, Node))
659     {
660         AslError (ASL_ERROR, ASL_MSG_TEMPORARY_OBJECT, Op,
661             Op->Asl.ExternalName);
662         return_ACPI_STATUS (Status);
663     }
664 
665    /* Object was found above, check for an illegal forward reference */
666 
667     if (Op->Asl.CompileFlags & OP_NOT_FOUND_DURING_LOAD)
668     {
669         /*
670          * During the load phase, this Op was flagged as a possible
671          * illegal forward reference. In other words, Op is a name path or
672          * name segment that refers to a named object declared after the
673          * reference. In this scinario, Node refers to the actual declaration
674          * and Op is a parse node that references the named object.
675          *
676          * Note:
677          *
678          * Object references inside of control methods are allowed to
679          * refer to objects declared outside of control methods.
680          *
681          * If the declaration and reference are both contained inside of the
682          * same method or outside of any method, this is a forward reference
683          * and should be reported as a compiler error.
684          */
685         DeclarationParentMethod = UtGetParentMethodNode (Node);
686         ReferenceParentMethod = UtGetParentMethodOp (Op);
687 
688         /* case 1: declaration and reference are both outside of method */
689 
690         if (!ReferenceParentMethod && !DeclarationParentMethod)
691         {
692             AslError (ASL_ERROR, ASL_MSG_ILLEGAL_FORWARD_REF, Op,
693                 Op->Asl.ExternalName);
694         }
695 
696         /* case 2: declaration and reference are both inside of the same method */
697 
698         else if (ReferenceParentMethod && DeclarationParentMethod &&
699             ReferenceParentMethod == DeclarationParentMethod->Op)
700         {
701              AslError (ASL_ERROR, ASL_MSG_ILLEGAL_FORWARD_REF, Op,
702                 Op->Asl.ExternalName);
703         }
704     }
705 
706     /* Check for a reference vs. name declaration */
707 
708     if (!(OpInfo->Flags & AML_NAMED) &&
709         !(OpInfo->Flags & AML_CREATE))
710     {
711         /* This node has been referenced, mark it for reference check */
712 
713         Node->Flags |= ANOBJ_IS_REFERENCED;
714     }
715 
716     /* Attempt to optimize the NamePath */
717 
718     OptOptimizeNamePath (Op, OpInfo->Flags, WalkState, Path, Node);
719 
720     /*
721      * 1) Dereference an alias (A name reference that is an alias)
722      *    Aliases are not nested, the alias always points to the final object
723      */
724     if ((Op->Asl.ParseOpcode != PARSEOP_ALIAS) &&
725         (Node->Type == ACPI_TYPE_LOCAL_ALIAS))
726     {
727         /* This node points back to the original PARSEOP_ALIAS */
728 
729         NextOp = Node->Op;
730 
731         /* The first child is the alias target op */
732 
733         NextOp = NextOp->Asl.Child;
734 
735         /* That in turn points back to original target alias node */
736 
737         if (NextOp->Asl.Node)
738         {
739             Node = NextOp->Asl.Node;
740         }
741 
742         /* Else - forward reference to alias, will be resolved later */
743     }
744 
745     /* 2) Check for a reference to a resource descriptor */
746 
747     if ((Node->Type == ACPI_TYPE_LOCAL_RESOURCE_FIELD) ||
748         (Node->Type == ACPI_TYPE_LOCAL_RESOURCE))
749     {
750         /*
751          * This was a reference to a field within a resource descriptor.
752          * Extract the associated field offset (either a bit or byte
753          * offset depending on the field type) and change the named
754          * reference into an integer for AML code generation
755          */
756         Offset = Node->Value;
757         TagBitLength = Node->Length;
758 
759         /*
760          * If a field is being created, generate the length (in bits) of
761          * the field. Note: Opcodes other than CreateXxxField and Index
762          * can come through here. For other opcodes, we just need to
763          * convert the resource tag reference to an integer offset.
764          */
765         switch (Op->Asl.Parent->Asl.AmlOpcode)
766         {
767         case AML_CREATE_FIELD_OP: /* Variable "Length" field, in bits */
768             /*
769              * We know the length operand is an integer constant because
770              * we know that it contains a reference to a resource
771              * descriptor tag.
772              */
773             FieldBitLength = (UINT32) Op->Asl.Next->Asl.Value.Integer;
774             break;
775 
776         case AML_CREATE_BIT_FIELD_OP:
777 
778             FieldBitLength = 1;
779             break;
780 
781         case AML_CREATE_BYTE_FIELD_OP:
782         case AML_INDEX_OP:
783 
784             FieldBitLength = 8;
785             break;
786 
787         case AML_CREATE_WORD_FIELD_OP:
788 
789             FieldBitLength = 16;
790             break;
791 
792         case AML_CREATE_DWORD_FIELD_OP:
793 
794             FieldBitLength = 32;
795             break;
796 
797         case AML_CREATE_QWORD_FIELD_OP:
798 
799             FieldBitLength = 64;
800             break;
801 
802         default:
803 
804             FieldBitLength = 0;
805             break;
806         }
807 
808         /* Check the field length against the length of the resource tag */
809 
810         if (FieldBitLength)
811         {
812             if (TagBitLength < FieldBitLength)
813             {
814                 Message = ASL_MSG_TAG_SMALLER;
815             }
816             else if (TagBitLength > FieldBitLength)
817             {
818                 Message = ASL_MSG_TAG_LARGER;
819             }
820 
821             if (Message)
822             {
823                 snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer),
824                     "Size mismatch, Tag: %u bit%s, Field: %u bit%s",
825                     TagBitLength, (TagBitLength > 1) ? "s" : "",
826                     FieldBitLength, (FieldBitLength > 1) ? "s" : "");
827 
828                 AslError (ASL_WARNING, Message, Op, AslGbl_MsgBuffer);
829             }
830         }
831 
832         /* Convert the BitOffset to a ByteOffset for certain opcodes */
833 
834         switch (Op->Asl.Parent->Asl.AmlOpcode)
835         {
836         case AML_CREATE_BYTE_FIELD_OP:
837         case AML_CREATE_WORD_FIELD_OP:
838         case AML_CREATE_DWORD_FIELD_OP:
839         case AML_CREATE_QWORD_FIELD_OP:
840         case AML_INDEX_OP:
841 
842             Offset = ACPI_DIV_8 (Offset);
843             break;
844 
845         default:
846 
847             break;
848         }
849 
850         /* Now convert this node to an integer whose value is the field offset */
851 
852         Op->Asl.AmlLength = 0;
853         Op->Asl.ParseOpcode = PARSEOP_INTEGER;
854         Op->Asl.Value.Integer = (UINT64) Offset;
855         Op->Asl.CompileFlags |= OP_IS_RESOURCE_FIELD;
856 
857         OpcGenerateAmlOpcode (Op);
858     }
859 
860     /* 3) Check for a method invocation */
861 
862     else if ((((Op->Asl.ParseOpcode == PARSEOP_NAMESTRING) || (Op->Asl.ParseOpcode == PARSEOP_NAMESEG)) &&
863                 (Node->Type == ACPI_TYPE_METHOD) &&
864                 (Op->Asl.Parent) &&
865                 (Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_METHOD))   ||
866 
867                 (Op->Asl.ParseOpcode == PARSEOP_METHODCALL))
868     {
869         /*
870          * A reference to a method within one of these opcodes is not an
871          * invocation of the method, it is simply a reference to the method.
872          *
873          * September 2016: Removed DeRefOf from this list
874          */
875         if ((Op->Asl.Parent) &&
876             ((Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_REFOF)     ||
877             (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_PACKAGE)    ||
878             (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_VAR_PACKAGE)||
879             (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_OBJECTTYPE)))
880         {
881             return_ACPI_STATUS (AE_OK);
882         }
883 
884         /*
885          * There are two types of method invocation:
886          * 1) Invocation with arguments -- the parser recognizes this
887          *    as a METHODCALL.
888          * 2) Invocation with no arguments --the parser cannot determine that
889          *    this is a method invocation, therefore we have to figure it out
890          *    here.
891          */
892         if (Node->Type != ACPI_TYPE_METHOD)
893         {
894             snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "%s is a %s",
895                 Op->Asl.ExternalName, AcpiUtGetTypeName (Node->Type));
896 
897             AslError (ASL_ERROR, ASL_MSG_NOT_METHOD, Op, AslGbl_MsgBuffer);
898             return_ACPI_STATUS (AE_OK);
899         }
900 
901         /* Save the method node in the caller's op */
902 
903         Op->Asl.Node = Node;
904         if (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_CONDREFOF)
905         {
906             return_ACPI_STATUS (AE_OK);
907         }
908 
909         /*
910          * This is a method invocation, with or without arguments.
911          * Count the number of arguments, each appears as a child
912          * under the parent node
913          */
914         Op->Asl.ParseOpcode = PARSEOP_METHODCALL;
915         UtSetParseOpName (Op);
916 
917         PassedArgs = 0;
918         NextOp = Op->Asl.Child;
919 
920         while (NextOp)
921         {
922             PassedArgs++;
923             NextOp = NextOp->Asl.Next;
924         }
925 
926         if (Node->Value != ASL_EXTERNAL_METHOD_UNKNOWN_PARAMS &&
927             Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_EXTERNAL)
928         {
929             /*
930              * Check the parsed arguments with the number expected by the
931              * method declaration itself
932              */
933             if (PassedArgs != Node->Value)
934             {
935                 if (Node->Flags & ANOBJ_IS_EXTERNAL)
936                 {
937                     snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer),
938                         "according to previous use, %s requires %u",
939                         Op->Asl.ExternalName, Node->Value);
940                 }
941                 else
942                 {
943                     snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer),
944 			"%s requires %u", Op->Asl.ExternalName,
945                         Node->Value);
946                 }
947 
948                 if (PassedArgs < Node->Value)
949                 {
950                     AslError (ASL_ERROR, ASL_MSG_ARG_COUNT_LO, Op, AslGbl_MsgBuffer);
951                 }
952                 else
953                 {
954                     AslError (ASL_ERROR, ASL_MSG_ARG_COUNT_HI, Op, AslGbl_MsgBuffer);
955                 }
956             }
957         }
958 
959         /*
960          * At this point, a method call to an external method has been
961          * detected. As of 11/19/2019, iASL does not support parameter counts
962          * for methods declared as external. Therefore, save the parameter
963          * count of the first method call and use this count check other
964          * method calls to ensure that the methods are being called with the
965          * same amount of parameters.
966          */
967         else if (Node->Type == ACPI_TYPE_METHOD &&
968             (Node->Flags & ANOBJ_IS_EXTERNAL) &&
969             Node->Value == ASL_EXTERNAL_METHOD_UNKNOWN_PARAMS &&
970             Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_EXTERNAL)
971         {
972             Node->Value = PassedArgs;
973         }
974     }
975 
976     /* 4) Check for an ASL Field definition */
977 
978     else if ((Op->Asl.Parent) &&
979             ((Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_FIELD)     ||
980              (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_BANKFIELD)))
981     {
982         /*
983          * Offset checking for fields. If the parent operation region has a
984          * constant length (known at compile time), we can check fields
985          * defined in that region against the region length. This will catch
986          * fields and field units that cannot possibly fit within the region.
987          *
988          * Note: Index fields do not directly reference an operation region,
989          * thus they are not included in this check.
990          */
991         if (Op == Op->Asl.Parent->Asl.Child)
992         {
993             /*
994              * This is the first child of the field node, which is
995              * the name of the region. Get the parse node for the
996              * region -- which contains the length of the region.
997              */
998             OwningOp = Node->Op;
999             Op->Asl.Parent->Asl.ExtraValue =
1000                 ACPI_MUL_8 ((UINT32) OwningOp->Asl.Value.Integer);
1001 
1002             /* Examine the field access width */
1003 
1004             switch ((UINT8) Op->Asl.Parent->Asl.Value.Integer)
1005             {
1006             case AML_FIELD_ACCESS_ANY:
1007             case AML_FIELD_ACCESS_BYTE:
1008             case AML_FIELD_ACCESS_BUFFER:
1009             default:
1010 
1011                 MinimumLength = 1;
1012                 break;
1013 
1014             case AML_FIELD_ACCESS_WORD:
1015 
1016                 MinimumLength = 2;
1017                 break;
1018 
1019             case AML_FIELD_ACCESS_DWORD:
1020 
1021                 MinimumLength = 4;
1022                 break;
1023 
1024             case AML_FIELD_ACCESS_QWORD:
1025 
1026                 MinimumLength = 8;
1027                 break;
1028             }
1029 
1030             /*
1031              * Is the region at least as big as the access width?
1032              * Note: DataTableRegions have 0 length
1033              */
1034             if (((UINT32) OwningOp->Asl.Value.Integer) &&
1035                 ((UINT32) OwningOp->Asl.Value.Integer < MinimumLength))
1036             {
1037                 AslError (ASL_ERROR, ASL_MSG_FIELD_ACCESS_WIDTH, Op, NULL);
1038             }
1039 
1040             /*
1041              * Check EC/CMOS/SMBUS fields to make sure that the correct
1042              * access type is used (BYTE for EC/CMOS, BUFFER for SMBUS)
1043              */
1044             SpaceIdOp = OwningOp->Asl.Child->Asl.Next;
1045             switch ((UINT32) SpaceIdOp->Asl.Value.Integer)
1046             {
1047             case ACPI_ADR_SPACE_EC:
1048             case ACPI_ADR_SPACE_CMOS:
1049             case ACPI_ADR_SPACE_GPIO:
1050 
1051                 if ((UINT8) Op->Asl.Parent->Asl.Value.Integer !=
1052                     AML_FIELD_ACCESS_BYTE)
1053                 {
1054                     AslError (ASL_ERROR, ASL_MSG_REGION_BYTE_ACCESS, Op, NULL);
1055                 }
1056                 break;
1057 
1058             case ACPI_ADR_SPACE_SMBUS:
1059             case ACPI_ADR_SPACE_IPMI:
1060             case ACPI_ADR_SPACE_GSBUS:
1061 
1062                 if ((UINT8) Op->Asl.Parent->Asl.Value.Integer !=
1063                     AML_FIELD_ACCESS_BUFFER)
1064                 {
1065                     AslError (ASL_ERROR, ASL_MSG_REGION_BUFFER_ACCESS, Op, NULL);
1066                 }
1067                 break;
1068 
1069             default:
1070 
1071                 /* Nothing to do for other address spaces */
1072 
1073                 break;
1074             }
1075         }
1076         else
1077         {
1078             /*
1079              * This is one element of the field list. Check to make sure
1080              * that it does not go beyond the end of the parent operation region.
1081              *
1082              * In the code below:
1083              *    Op->Asl.Parent->Asl.ExtraValue      - Region Length (bits)
1084              *    Op->Asl.ExtraValue                  - Field start offset (bits)
1085              *    Op->Asl.Child->Asl.Value.Integer32  - Field length (bits)
1086              *    Op->Asl.Child->Asl.ExtraValue       - Field access width (bits)
1087              */
1088             if (Op->Asl.Parent->Asl.ExtraValue && Op->Asl.Child)
1089             {
1090                 XfCheckFieldRange (Op,
1091                     Op->Asl.Parent->Asl.ExtraValue,
1092                     Op->Asl.ExtraValue,
1093                     (UINT32) Op->Asl.Child->Asl.Value.Integer,
1094                     Op->Asl.Child->Asl.ExtraValue);
1095             }
1096         }
1097     }
1098 
1099     /*
1100      * 5) Check for external resolution
1101      *
1102      * By this point, everything should be loaded in the namespace. If a
1103      * namespace lookup results in a namespace node that is an external, it
1104      * means that this named object was not defined in the input ASL. This
1105      * causes issues because there are plenty of incidents where developers
1106      * use the external keyword to suppress compiler errors about undefined
1107      * objects. Note: this only applies when compiling multiple definition
1108      * blocks.
1109      *
1110      * Do not check for external resolution in the following cases:
1111      *
1112      * case 1) External (ABCD)
1113      *
1114      *         This declares ABCD as an external so there is no requirement for
1115      *         ABCD to be loaded in the namespace when analyzing the actual
1116      *         External() statement.
1117      *
1118      * case 2) CondRefOf (ABCD)
1119      *
1120      *         This operator will query the ACPI namespace on the existence of
1121      *         ABCD. If ABCD does not exist, this operator will return a 0
1122      *         without incurring AML runtime errors. Therefore, ABCD is allowed
1123      *         to not exist when analyzing the CondRefOf operator.
1124      *
1125      * case 3) External (ABCD)
1126      *         if (CondRefOf (ABCD))
1127      *         {
1128      *             Store (0, ABCD)
1129      *         }
1130      *
1131      *         In this case, ABCD is accessed only if it exists due to the if
1132      *         statement so there is no need to flag the ABCD nested in the
1133      *         store operator.
1134      */
1135     if (AslGbl_ParseTreeRoot->Asl.Child && AslGbl_ParseTreeRoot->Asl.Child->Asl.Next &&
1136         (Node->Flags & ANOBJ_IS_EXTERNAL) &&
1137         Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_EXTERNAL &&
1138         Op->Asl.ParseOpcode != PARSEOP_EXTERNAL &&
1139         Op->Asl.Parent->Asl.ParseOpcode != PARSEOP_CONDREFOF &&
1140         !XfRefIsGuardedByIfCondRefOf (Node, Op))
1141     {
1142         AslError (ASL_ERROR, ASL_MSG_UNDEFINED_EXTERNAL, Op, NULL);
1143     }
1144 
1145     /* 5) Check for a connection object */
1146 #if 0
1147     else if (Op->Asl.Parent->Asl.ParseOpcode == PARSEOP_CONNECTION)
1148     {
1149         return_ACPI_STATUS (Status);
1150     }
1151 #endif
1152 
1153     Op->Asl.Node = Node;
1154     return_ACPI_STATUS (Status);
1155 }
1156 
1157 
1158 /*******************************************************************************
1159  *
1160  * FUNCTION:    XfRefIsGuardedByIfCondRefOf
1161  *
1162  * PARAMETERS:  Node        - Named object reference node
1163  *              Op          - Named object reference parse node
1164  *
1165  * RETURN:      BOOLEAN
1166  *
1167  * DESCRIPTION: returns true if Op checked inside if (CondRefOf (...))
1168  *              refers to Node.
1169  *
1170  ******************************************************************************/
1171 
1172 static BOOLEAN
1173 XfRefIsGuardedByIfCondRefOf (
1174     ACPI_NAMESPACE_NODE     *Node,
1175     ACPI_PARSE_OBJECT       *Op)
1176 {
1177     ACPI_PARSE_OBJECT       *Parent = Op->Asl.Parent;
1178 
1179 
1180     while (Parent)
1181     {
1182         if (Parent->Asl.ParseOpcode == PARSEOP_IF &&
1183             XfFindCondRefOfName (Node, Parent->Asl.Child))
1184         {
1185             return (TRUE);
1186         }
1187 
1188         Parent = Parent->Asl.Parent;
1189     }
1190 
1191     return (FALSE);
1192 }
1193 
1194 
1195 /*******************************************************************************
1196  *
1197  * FUNCTION:    XfRefIsGuardedByIfCondRefOf
1198  *
1199  * PARAMETERS:  Node        - Named object reference node
1200  *              Op          - Named object reference parse node
1201  *
1202  * RETURN:      BOOLEAN
1203  *
1204  * DESCRIPTION: returns true if Op checked inside if (CondRefOf (...))
1205  *              refers to Node.
1206  *
1207  ******************************************************************************/
1208 
1209 static BOOLEAN
1210 XfFindCondRefOfName (
1211     ACPI_NAMESPACE_NODE     *Node,
1212     ACPI_PARSE_OBJECT       *Op)
1213 {
1214     BOOLEAN                 CondRefOfFound = FALSE;
1215 
1216 
1217     if (!Op)
1218     {
1219         return (FALSE);
1220     }
1221 
1222     switch (Op->Asl.ParseOpcode)
1223     {
1224     case PARSEOP_CONDREFOF:
1225 
1226         return (Op->Asl.Child->Common.Node == Node);
1227         break;
1228 
1229     case PARSEOP_LAND:
1230 
1231         CondRefOfFound = XfFindCondRefOfName (Node, Op->Asl.Child);
1232         if (CondRefOfFound)
1233         {
1234             return (TRUE);
1235         }
1236 
1237         return (XfFindCondRefOfName (Node, Op->Asl.Child->Asl.Next));
1238         break;
1239 
1240     default:
1241 
1242         return (FALSE);
1243         break;
1244     }
1245 }
1246 
1247 
1248 /*******************************************************************************
1249  *
1250  * FUNCTION:    XfNamespaceLocateEnd
1251  *
1252  * PARAMETERS:  ASL_WALK_CALLBACK
1253  *
1254  * RETURN:      Status
1255  *
1256  * DESCRIPTION: Ascending callback used during cross reference. We only
1257  *              need to worry about scope management here.
1258  *
1259  ******************************************************************************/
1260 
1261 static ACPI_STATUS
1262 XfNamespaceLocateEnd (
1263     ACPI_PARSE_OBJECT       *Op,
1264     UINT32                  Level,
1265     void                    *Context)
1266 {
1267     ACPI_WALK_STATE         *WalkState = (ACPI_WALK_STATE *) Context;
1268     const ACPI_OPCODE_INFO  *OpInfo;
1269 
1270 
1271     ACPI_FUNCTION_TRACE (XfNamespaceLocateEnd);
1272 
1273 
1274     /* We are only interested in opcodes that have an associated name */
1275 
1276     OpInfo = AcpiPsGetOpcodeInfo (Op->Asl.AmlOpcode);
1277     if (!(OpInfo->Flags & AML_NAMED))
1278     {
1279         return_ACPI_STATUS (AE_OK);
1280     }
1281 
1282     /* Not interested in name references, we did not open a scope for them */
1283 
1284     if ((Op->Asl.ParseOpcode == PARSEOP_NAMESTRING) ||
1285         (Op->Asl.ParseOpcode == PARSEOP_NAMESEG)    ||
1286         (Op->Asl.ParseOpcode == PARSEOP_METHODCALL) ||
1287         (Op->Asl.ParseOpcode == PARSEOP_EXTERNAL))
1288     {
1289         return_ACPI_STATUS (AE_OK);
1290     }
1291 
1292     /* Pop the scope stack if necessary */
1293 
1294     if (AcpiNsOpensScope (AslMapNamedOpcodeToDataType (Op->Asl.AmlOpcode)))
1295     {
1296 
1297         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
1298             "%s: Popping scope for Op %p\n",
1299             AcpiUtGetTypeName (OpInfo->ObjectType), Op));
1300 
1301         (void) AcpiDsScopeStackPop (WalkState);
1302     }
1303 
1304     return_ACPI_STATUS (AE_OK);
1305 }
1306 
1307 
1308 /*******************************************************************************
1309  *
1310  * FUNCTION:    XfValidateCrossReference
1311  *
1312  * PARAMETERS:  Op                      - Parse Op that references the object
1313  *              OpInfo                  - Parse Op info struct
1314  *              Node                    - Node for the referenced object
1315  *
1316  * RETURN:      TRUE if the reference is legal, FALSE otherwise
1317  *
1318  * DESCRIPTION: Determine if a reference to another object is allowed.
1319  *
1320  * EXAMPLE:
1321  *      Method (A) {Name (INT1, 1)}     Declaration of object INT1
1322  *      Method (B) (Store (2, \A.INT1)} Illegal reference to object INT1
1323  *                                      (INT1 is temporary, valid only during
1324  *                                      execution of A)
1325  *
1326  * NOTES:
1327  *      A null pointer returned by either UtGetParentMethodOp or
1328  *      UtGetParentMethodNode indicates that the parameter object is not
1329  *      within a control method.
1330  *
1331  *      Five cases are handled: Case(Op, Node)
1332  *      1) Case(0,0): Op is not within a method, Node is not    --> OK
1333  *      2) Case(0,1): Op is not within a method, but Node is    --> Illegal
1334  *      3) Case(1,0): Op is within a method, Node is not        --> OK
1335  *      4) Case(1,1): Both are within the same method           --> OK
1336  *      5) Case(1,1): Both are in methods, but not same method  --> Illegal
1337  *
1338  ******************************************************************************/
1339 
1340 static BOOLEAN
1341 XfValidateCrossReference (
1342     ACPI_PARSE_OBJECT       *Op,
1343     const ACPI_OPCODE_INFO  *OpInfo,
1344     ACPI_NAMESPACE_NODE     *Node)
1345 {
1346     ACPI_PARSE_OBJECT       *ReferencingMethodOp;
1347     ACPI_NAMESPACE_NODE     *ReferencedMethodNode;
1348 
1349 
1350     /* Ignore actual named (and related) object declarations */
1351 
1352     if (OpInfo->Flags & (AML_NAMED | AML_CREATE | AML_DEFER | AML_HAS_ARGS))
1353     {
1354         return (TRUE);
1355     }
1356 
1357     /*
1358      * 1) Search upwards in parse tree for owner of the referencing object
1359      * 2) Search upwards in namespace to find the owner of the referenced object
1360      */
1361     ReferencingMethodOp = UtGetParentMethodOp (Op);
1362     ReferencedMethodNode = UtGetParentMethodNode (Node);
1363 
1364     if (!ReferencingMethodOp && !ReferencedMethodNode)
1365     {
1366         /*
1367          * 1) Case (0,0): Both Op and Node are not within methods
1368          * --> OK
1369          */
1370         return (TRUE);
1371     }
1372 
1373     if (!ReferencingMethodOp && ReferencedMethodNode)
1374     {
1375         /*
1376          * 2) Case (0,1): Op is not in a method, but Node is within a
1377          * method --> illegal
1378          */
1379         return (FALSE);
1380     }
1381     else if (ReferencingMethodOp && !ReferencedMethodNode)
1382     {
1383         /*
1384          * 3) Case (1,0): Op is within a method, but Node is not
1385          * --> OK
1386          */
1387         return (TRUE);
1388     }
1389     else if (ReferencingMethodOp->Asl.Node == ReferencedMethodNode)
1390     {
1391         /*
1392          * 4) Case (1,1): Both Op and Node are within the same method
1393          * --> OK
1394          */
1395         return (TRUE);
1396     }
1397     else
1398     {
1399         /*
1400          * 5) Case (1,1), Op and Node are in different methods
1401          * --> Illegal
1402          */
1403         return (FALSE);
1404     }
1405 }
1406