xref: /netbsd-src/sys/external/bsd/acpica/dist/compiler/dtutils.c (revision 987b04d624d6d5e25e3e80d683a4ebe80fe47dcf)
1 /******************************************************************************
2  *
3  * Module Name: dtutils.c - Utility routines for the data table compiler
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2023, 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 MERCHANTABILITY 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 "actables.h"
46 
47 #define _COMPONENT          DT_COMPILER
48         ACPI_MODULE_NAME    ("dtutils")
49 
50 /* Local prototypes */
51 
52 static void
53 DtSum (
54     DT_SUBTABLE             *Subtable,
55     void                    *Context,
56     void                    *ReturnValue);
57 
58 
59 /******************************************************************************
60  *
61  * FUNCTION:    DtError
62  *
63  * PARAMETERS:  Level               - Seriousness (Warning/error, etc.)
64  *              MessageId           - Index into global message buffer
65  *              Op                  - Parse node where error happened
66  *              ExtraMessage        - additional error message
67  *
68  * RETURN:      None
69  *
70  * DESCRIPTION: Common error interface for data table compiler
71  *
72  *****************************************************************************/
73 
74 void
75 DtError (
76     UINT8                   Level,
77     UINT16                  MessageId,
78     DT_FIELD                *FieldObject,
79     char                    *ExtraMessage)
80 {
81     UINT32                  Line = 0;
82 
83 
84     /* Field object could be NULL */
85 
86     if (FieldObject)
87     {
88         Line = FieldObject->Line;
89     }
90 
91     /* Check if user wants to ignore this exception */
92 
93     if (AslIsExceptionIgnored (AslGbl_Files[ASL_FILE_INPUT].Filename,
94         Line, Level, MessageId))
95     {
96         return;
97     }
98 
99     if (FieldObject)
100     {
101         AslCommonError (Level, MessageId,
102             FieldObject->Line,
103             FieldObject->Line,
104             FieldObject->ByteOffset,
105             FieldObject->Column,
106             AslGbl_Files[ASL_FILE_INPUT].Filename, ExtraMessage);
107     }
108     else
109     {
110         AslCommonError (Level, MessageId, 0,
111             0, 0, 0, 0, ExtraMessage);
112     }
113 }
114 
115 
116 /******************************************************************************
117  *
118  * FUNCTION:    DtNameError
119  *
120  * PARAMETERS:  Level               - Seriousness (Warning/error, etc.)
121  *              MessageId           - Index into global message buffer
122  *              Op                  - Parse node where error happened
123  *              ExtraMessage        - additional error message
124  *
125  * RETURN:      None
126  *
127  * DESCRIPTION: Error interface for named objects
128  *
129  *****************************************************************************/
130 
131 void
132 DtNameError (
133     UINT8                   Level,
134     UINT16                  MessageId,
135     DT_FIELD                *FieldObject,
136     char                    *ExtraMessage)
137 {
138 
139     switch (Level)
140     {
141     case ASL_WARNING2:
142     case ASL_WARNING3:
143 
144         if (AslGbl_WarningLevel < Level)
145         {
146             return;
147         }
148         break;
149 
150     default:
151 
152         break;
153     }
154 
155     if (FieldObject)
156     {
157         AslCommonError (Level, MessageId,
158             FieldObject->Line,
159             FieldObject->Line,
160             FieldObject->ByteOffset,
161             FieldObject->NameColumn,
162             AslGbl_Files[ASL_FILE_INPUT].Filename, ExtraMessage);
163     }
164     else
165     {
166         AslCommonError (Level, MessageId, 0,
167             0, 0, 0, 0, ExtraMessage);
168     }
169 }
170 
171 
172 /*******************************************************************************
173  *
174  * FUNCTION:    DtFatal
175  *
176  * PARAMETERS:  None
177  *
178  * RETURN:      None
179  *
180  * DESCRIPTION: Dump the error log and abort the compiler. Used for serious
181  *              compile or I/O errors
182  *
183  ******************************************************************************/
184 
185 void
186 DtFatal (
187     UINT16                  MessageId,
188     DT_FIELD                *FieldObject,
189     char                    *ExtraMessage)
190 {
191 
192     DtError (ASL_ERROR, MessageId, FieldObject, ExtraMessage);
193 
194 /*
195  * TBD: remove this entire function, DtFatal
196  *
197  * We cannot abort the compiler on error, because we may be compiling a
198  * list of files. We must move on to the next file.
199  */
200 #ifdef __OBSOLETE
201     CmCleanupAndExit ();
202     exit (1);
203 #endif
204 }
205 
206 
207 /*******************************************************************************
208  *
209  * FUNCTION:    DtDoConstant
210  *
211  * PARAMETERS:  String              - Only hex constants are supported,
212  *                                    regardless of whether the 0x prefix
213  *                                    is used
214  *
215  * RETURN:      Converted Integer
216  *
217  * DESCRIPTION: Convert a string to an integer, with overflow/error checking.
218  *
219  ******************************************************************************/
220 
221 UINT64
222 DtDoConstant (
223     char                    *String)
224 {
225     UINT64                  ConvertedInteger;
226 
227 
228     /*
229      * TBD: The ImplicitStrtoul64 function does not report overflow
230      * conditions. The input string is simply truncated. If it is
231      * desired to report overflow to the table compiler, this should
232      * somehow be added here. Note: integers that are prefixed with 0x
233      * or not are both hex integers.
234      */
235     ConvertedInteger = AcpiUtImplicitStrtoul64 (String);
236     return (ConvertedInteger);
237 }
238 
239 /******************************************************************************
240  *
241  * FUNCTION:    DtGetFieldValue
242  *
243  * PARAMETERS:  Field               - Current field list pointer
244  *
245  * RETURN:      Field value
246  *
247  * DESCRIPTION: Get field value
248  *
249  *****************************************************************************/
250 
251 char *
252 DtGetFieldValue (
253     DT_FIELD                *Field)
254 {
255     if (!Field)
256     {
257         return (NULL);
258     }
259 
260     return (Field->Value);
261 }
262 
263 
264 /******************************************************************************
265  *
266  * FUNCTION:    DtGetFieldType
267  *
268  * PARAMETERS:  Info                - Data table info
269  *
270  * RETURN:      Field type
271  *
272  * DESCRIPTION: Get field type
273  *
274  *****************************************************************************/
275 
276 UINT8
277 DtGetFieldType (
278     ACPI_DMTABLE_INFO       *Info)
279 {
280     UINT8                   Type;
281 
282 
283     /* DT_FLAG means that this is the start of a block of flag bits */
284     /* TBD - we can make these a separate opcode later */
285 
286     if (Info->Flags & DT_FLAG)
287     {
288         return (DT_FIELD_TYPE_FLAGS_INTEGER);
289     }
290 
291     /* Type is based upon the opcode for this field in the info table */
292 
293     switch (Info->Opcode)
294     {
295     case ACPI_DMT_FLAG0:
296     case ACPI_DMT_FLAG1:
297     case ACPI_DMT_FLAG2:
298     case ACPI_DMT_FLAG3:
299     case ACPI_DMT_FLAG4:
300     case ACPI_DMT_FLAG5:
301     case ACPI_DMT_FLAG6:
302     case ACPI_DMT_FLAG7:
303     case ACPI_DMT_FLAGS0:
304     case ACPI_DMT_FLAGS1:
305     case ACPI_DMT_FLAGS2:
306     case ACPI_DMT_FLAGS8_2:
307     case ACPI_DMT_FLAGS4:
308     case ACPI_DMT_FLAGS4_0:
309     case ACPI_DMT_FLAGS4_4:
310     case ACPI_DMT_FLAGS4_8:
311     case ACPI_DMT_FLAGS4_12:
312     case ACPI_DMT_FLAGS16_16:
313 
314         Type = DT_FIELD_TYPE_FLAG;
315         break;
316 
317     case ACPI_DMT_NAME4:
318     case ACPI_DMT_SIG:
319     case ACPI_DMT_NAME6:
320     case ACPI_DMT_NAME8:
321     case ACPI_DMT_STRING:
322     case ACPI_DMT_IVRS_UNTERMINATED_STRING:
323 
324         Type = DT_FIELD_TYPE_STRING;
325         break;
326 
327     case ACPI_DMT_BUFFER:
328     case ACPI_DMT_RAW_BUFFER:
329     case ACPI_DMT_BUF7:
330     case ACPI_DMT_BUF10:
331     case ACPI_DMT_BUF12:
332     case ACPI_DMT_BUF16:
333     case ACPI_DMT_BUF18:
334     case ACPI_DMT_BUF32:
335     case ACPI_DMT_BUF112:
336     case ACPI_DMT_BUF128:
337     case ACPI_DMT_PCI_PATH:
338     case ACPI_DMT_PMTT_VENDOR:
339 
340         Type = DT_FIELD_TYPE_BUFFER;
341         break;
342 
343     case ACPI_DMT_GAS:
344     case ACPI_DMT_HESTNTFY:
345     case ACPI_DMT_IORTMEM:
346 
347         Type = DT_FIELD_TYPE_INLINE_SUBTABLE;
348         break;
349 
350     case ACPI_DMT_UNICODE:
351     case ACPI_DMT_WPBT_UNICODE:
352 
353         Type = DT_FIELD_TYPE_UNICODE;
354         break;
355 
356     case ACPI_DMT_UUID:
357 
358         Type = DT_FIELD_TYPE_UUID;
359         break;
360 
361     case ACPI_DMT_DEVICE_PATH:
362 
363         Type = DT_FIELD_TYPE_DEVICE_PATH;
364         break;
365 
366     case ACPI_DMT_LABEL:
367 
368         Type = DT_FIELD_TYPE_LABEL;
369         break;
370 
371     default:
372 
373         Type = DT_FIELD_TYPE_INTEGER;
374         break;
375     }
376 
377     return (Type);
378 }
379 
380 
381 /******************************************************************************
382  *
383  * FUNCTION:    DtGetBufferLength
384  *
385  * PARAMETERS:  Buffer              - List of integers,
386  *                                    for example "10 3A 4F 2E"
387  *
388  * RETURN:      Count of integer
389  *
390  * DESCRIPTION: Get length of bytes needed to store the integers
391  *
392  *****************************************************************************/
393 
394 UINT32
395 DtGetBufferLength (
396     char                    *Buffer)
397 {
398     UINT32                  ByteLength = 0;
399 
400 
401     while (*Buffer)
402     {
403         if (*Buffer == ' ')
404         {
405             ByteLength++;
406 
407             while (*Buffer == ' ')
408             {
409                 Buffer++;
410             }
411         }
412 
413         Buffer++;
414     }
415 
416     return (++ByteLength);
417 }
418 
419 
420 /******************************************************************************
421  *
422  * FUNCTION:    DtGetFieldLength
423  *
424  * PARAMETERS:  Field               - Current field
425  *              Info                - Data table info
426  *
427  * RETURN:      Field length
428  *
429  * DESCRIPTION: Get length of bytes needed to compile the field
430  *
431  * Note: This function must remain in sync with AcpiDmDumpTable.
432  *
433  *****************************************************************************/
434 
435 UINT32
436 DtGetFieldLength (
437     DT_FIELD                *Field,
438     ACPI_DMTABLE_INFO       *Info)
439 {
440     UINT32                  ByteLength = 0;
441     char                    *Value;
442 
443 
444     /* Length is based upon the opcode for this field in the info table */
445 
446     switch (Info->Opcode)
447     {
448     case ACPI_DMT_FLAG0:
449     case ACPI_DMT_FLAG1:
450     case ACPI_DMT_FLAG2:
451     case ACPI_DMT_FLAG3:
452     case ACPI_DMT_FLAG4:
453     case ACPI_DMT_FLAG5:
454     case ACPI_DMT_FLAG6:
455     case ACPI_DMT_FLAG7:
456     case ACPI_DMT_FLAGS0:
457     case ACPI_DMT_FLAGS1:
458     case ACPI_DMT_FLAGS2:
459     case ACPI_DMT_FLAGS8_2:
460     case ACPI_DMT_FLAGS4:
461     case ACPI_DMT_FLAGS4_0:
462     case ACPI_DMT_FLAGS4_4:
463     case ACPI_DMT_FLAGS4_8:
464     case ACPI_DMT_FLAGS4_12:
465     case ACPI_DMT_FLAGS16_16:
466     case ACPI_DMT_LABEL:
467     case ACPI_DMT_EXTRA_TEXT:
468 
469         ByteLength = 0;
470         break;
471 
472     case ACPI_DMT_UINT8:
473     case ACPI_DMT_CHKSUM:
474     case ACPI_DMT_SPACEID:
475     case ACPI_DMT_ACCWIDTH:
476     case ACPI_DMT_CEDT:
477     case ACPI_DMT_IVRS:
478     case ACPI_DMT_IVRS_DE:
479     case ACPI_DMT_GTDT:
480     case ACPI_DMT_MADT:
481     case ACPI_DMT_MPAM_LOCATOR:
482     case ACPI_DMT_PCCT:
483     case ACPI_DMT_PMTT:
484     case ACPI_DMT_PPTT:
485     case ACPI_DMT_RGRT:
486     case ACPI_DMT_SDEV:
487     case ACPI_DMT_SRAT:
488     case ACPI_DMT_AEST:
489     case ACPI_DMT_AEST_RES:
490     case ACPI_DMT_AEST_XFACE:
491     case ACPI_DMT_AEST_XRUPT:
492     case ACPI_DMT_ASF:
493     case ACPI_DMT_CDAT:
494     case ACPI_DMT_HESTNTYP:
495     case ACPI_DMT_FADTPM:
496     case ACPI_DMT_EINJACT:
497     case ACPI_DMT_EINJINST:
498     case ACPI_DMT_ERSTACT:
499     case ACPI_DMT_ERSTINST:
500     case ACPI_DMT_DMAR_SCOPE:
501     case ACPI_DMT_VIOT:
502 
503         ByteLength = 1;
504         break;
505 
506     case ACPI_DMT_ASPT:
507     case ACPI_DMT_UINT16:
508     case ACPI_DMT_DMAR:
509     case ACPI_DMT_HEST:
510     case ACPI_DMT_HMAT:
511     case ACPI_DMT_NFIT:
512     case ACPI_DMT_PCI_PATH:
513     case ACPI_DMT_PHAT:
514 
515         ByteLength = 2;
516         break;
517 
518     case ACPI_DMT_UINT24:
519 
520         ByteLength = 3;
521         break;
522 
523     case ACPI_DMT_UINT32:
524     case ACPI_DMT_AEST_CACHE:
525     case ACPI_DMT_AEST_GIC:
526     case ACPI_DMT_NAME4:
527     case ACPI_DMT_SIG:
528     case ACPI_DMT_LPIT:
529     case ACPI_DMT_TPM2:
530 
531         ByteLength = 4;
532         break;
533 
534     case ACPI_DMT_UINT40:
535 
536         ByteLength = 5;
537         break;
538 
539     case ACPI_DMT_UINT48:
540     case ACPI_DMT_NAME6:
541 
542         ByteLength = 6;
543         break;
544 
545     case ACPI_DMT_UINT56:
546     case ACPI_DMT_BUF7:
547 
548         ByteLength = 7;
549         break;
550 
551     case ACPI_DMT_UINT64:
552     case ACPI_DMT_NAME8:
553 
554         ByteLength = 8;
555         break;
556 
557     case ACPI_DMT_STRING:
558 
559         Value = DtGetFieldValue (Field);
560         if (Value)
561         {
562             ByteLength = strlen (Value) + 1;
563         }
564         else
565         {   /* At this point, this is a fatal error */
566 
567             snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
568             DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
569             return (0);
570         }
571         break;
572 
573     case ACPI_DMT_IVRS_UNTERMINATED_STRING:
574 
575         Value = DtGetFieldValue (Field);
576         if (Value)
577         {
578             ByteLength = strlen (Value);
579         }
580         else
581         {   /* At this point, this is a fatal error */
582 
583             snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
584             DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
585             return (0);
586         }
587         break;
588 
589     case ACPI_DMT_GAS:
590 
591         ByteLength = sizeof (ACPI_GENERIC_ADDRESS);
592         break;
593 
594     case ACPI_DMT_HESTNTFY:
595 
596         ByteLength = sizeof (ACPI_HEST_NOTIFY);
597         break;
598 
599     case ACPI_DMT_IORTMEM:
600 
601         ByteLength = sizeof (ACPI_IORT_MEMORY_ACCESS);
602         break;
603 
604     case ACPI_DMT_BUFFER:
605     case ACPI_DMT_RAW_BUFFER:
606     case ACPI_DMT_PMTT_VENDOR:
607 
608         Value = DtGetFieldValue (Field);
609         if (Value)
610         {
611             ByteLength = DtGetBufferLength (Value);
612         }
613         else
614         {   /* At this point, this is a fatal error */
615 
616             snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
617             DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
618             return (0);
619         }
620         break;
621 
622     case ACPI_DMT_BUF10:
623 
624         ByteLength = 10;
625         break;
626 
627     case ACPI_DMT_BUF12:
628 
629         ByteLength = 12;
630         break;
631 
632     case ACPI_DMT_BUF16:
633     case ACPI_DMT_UUID:
634 
635         ByteLength = 16;
636         break;
637 
638     case ACPI_DMT_BUF18:
639 
640         ByteLength = 18;
641         break;
642 
643     case ACPI_DMT_BUF32:
644 
645         ByteLength = 32;
646         break;
647 
648     case ACPI_DMT_BUF112:
649 
650         ByteLength = 112;
651         break;
652 
653     case ACPI_DMT_BUF128:
654 
655         ByteLength = 128;
656         break;
657 
658     case ACPI_DMT_UNICODE:
659     case ACPI_DMT_WPBT_UNICODE:
660 
661         Value = DtGetFieldValue (Field);
662 
663         /* TBD: error if Value is NULL? (as below?) */
664 
665         ByteLength = (strlen (Value) + 1) * sizeof (UINT16);
666         break;
667 
668     default:
669 
670         DtFatal (ASL_MSG_COMPILER_INTERNAL, Field, "Invalid table opcode");
671         return (0);
672     }
673 
674     return (ByteLength);
675 }
676 
677 
678 /******************************************************************************
679  *
680  * FUNCTION:    DtSum
681  *
682  * PARAMETERS:  DT_WALK_CALLBACK:
683  *              Subtable            - Subtable
684  *              Context             - Unused
685  *              ReturnValue         - Store the checksum of subtable
686  *
687  * RETURN:      Status
688  *
689  * DESCRIPTION: Get the checksum of subtable
690  *
691  *****************************************************************************/
692 
693 static void
694 DtSum (
695     DT_SUBTABLE             *Subtable,
696     void                    *Context,
697     void                    *ReturnValue)
698 {
699     UINT8                   Checksum;
700     UINT8                   *Sum = ReturnValue;
701 
702 
703     Checksum = AcpiUtChecksum (Subtable->Buffer, Subtable->Length);
704     *Sum = (UINT8) (*Sum + Checksum);
705 }
706 
707 
708 /******************************************************************************
709  *
710  * FUNCTION:    DtSetTableChecksum
711  *
712  * PARAMETERS:  ChecksumPointer     - Where to return the checksum
713  *
714  * RETURN:      None
715  *
716  * DESCRIPTION: Set checksum of the whole data table into the checksum field
717  *
718  *****************************************************************************/
719 
720 void
721 DtSetTableChecksum (
722     UINT8                   *ChecksumPointer)
723 {
724     UINT8                   Checksum = 0;
725     UINT8                   OldSum;
726 
727 
728     DtWalkTableTree (AslGbl_RootTable, DtSum, NULL, &Checksum);
729 
730     OldSum = *ChecksumPointer;
731     Checksum = (UINT8) (Checksum - OldSum);
732 
733     /* Compute the final checksum */
734 
735     Checksum = (UINT8) (0 - Checksum);
736     *ChecksumPointer = Checksum;
737 }
738 
739 
740 /******************************************************************************
741  *
742  * FUNCTION:    DtSetTableLength
743  *
744  * PARAMETERS:  None
745  *
746  * RETURN:      None
747  *
748  * DESCRIPTION: Walk the subtables and set all the length fields
749  *
750  *****************************************************************************/
751 
752 void
753 DtSetTableLength (
754     void)
755 {
756     DT_SUBTABLE             *ParentTable;
757     DT_SUBTABLE             *ChildTable;
758 
759 
760     ParentTable = AslGbl_RootTable;
761     ChildTable = NULL;
762 
763     if (!ParentTable)
764     {
765         return;
766     }
767 
768     DtSetSubtableLength (ParentTable);
769 
770     while (1)
771     {
772         ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
773         if (ChildTable)
774         {
775             if (ChildTable->LengthField)
776             {
777                 DtSetSubtableLength (ChildTable);
778             }
779 
780             if (ChildTable->Child)
781             {
782                 ParentTable = ChildTable;
783                 ChildTable = NULL;
784             }
785             else
786             {
787                 ParentTable->TotalLength += ChildTable->TotalLength;
788                 if (ParentTable->LengthField)
789                 {
790                     DtSetSubtableLength (ParentTable);
791                 }
792             }
793         }
794         else
795         {
796             ChildTable = ParentTable;
797 
798             if (ChildTable == AslGbl_RootTable)
799             {
800                 break;
801             }
802 
803             ParentTable = DtGetParentSubtable (ParentTable);
804 
805             ParentTable->TotalLength += ChildTable->TotalLength;
806             if (ParentTable->LengthField)
807             {
808                 DtSetSubtableLength (ParentTable);
809             }
810         }
811     }
812 }
813 
814 
815 /******************************************************************************
816  *
817  * FUNCTION:    DtWalkTableTree
818  *
819  * PARAMETERS:  StartTable          - Subtable in the tree where walking begins
820  *              UserFunction        - Called during the walk
821  *              Context             - Passed to user function
822  *              ReturnValue         - The return value of UserFunction
823  *
824  * RETURN:      None
825  *
826  * DESCRIPTION: Performs a depth-first walk of the subtable tree
827  *
828  *****************************************************************************/
829 
830 void
831 DtWalkTableTree (
832     DT_SUBTABLE             *StartTable,
833     DT_WALK_CALLBACK        UserFunction,
834     void                    *Context,
835     void                    *ReturnValue)
836 {
837     DT_SUBTABLE             *ParentTable;
838     DT_SUBTABLE             *ChildTable;
839 
840 
841     ParentTable = StartTable;
842     ChildTable = NULL;
843 
844     if (!ParentTable)
845     {
846         return;
847     }
848 
849     UserFunction (ParentTable, Context, ReturnValue);
850 
851     while (1)
852     {
853         ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
854         if (ChildTable)
855         {
856             UserFunction (ChildTable, Context, ReturnValue);
857 
858             if (ChildTable->Child)
859             {
860                 ParentTable = ChildTable;
861                 ChildTable = NULL;
862             }
863         }
864         else
865         {
866             ChildTable = ParentTable;
867             if (ChildTable == AslGbl_RootTable)
868             {
869                 break;
870             }
871 
872             ParentTable = DtGetParentSubtable (ParentTable);
873 
874             if (ChildTable->Peer == StartTable)
875             {
876                 break;
877             }
878         }
879     }
880 }
881