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dtutils.c revision 1.16.2.1
      1 /******************************************************************************
      2  *
      3  * Module Name: dtutils.c - Utility routines for the data table compiler
      4  *
      5  *****************************************************************************/
      6 
      7 /*
      8  * Copyright (C) 2000 - 2021, 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_FLAGS4:
    307     case ACPI_DMT_FLAGS4_0:
    308     case ACPI_DMT_FLAGS4_4:
    309     case ACPI_DMT_FLAGS4_8:
    310     case ACPI_DMT_FLAGS4_12:
    311     case ACPI_DMT_FLAGS16_16:
    312 
    313         Type = DT_FIELD_TYPE_FLAG;
    314         break;
    315 
    316     case ACPI_DMT_NAME4:
    317     case ACPI_DMT_SIG:
    318     case ACPI_DMT_NAME6:
    319     case ACPI_DMT_NAME8:
    320     case ACPI_DMT_STRING:
    321     case ACPI_DMT_IVRS_UNTERMINATED_STRING:
    322 
    323         Type = DT_FIELD_TYPE_STRING;
    324         break;
    325 
    326     case ACPI_DMT_BUFFER:
    327     case ACPI_DMT_RAW_BUFFER:
    328     case ACPI_DMT_BUF7:
    329     case ACPI_DMT_BUF10:
    330     case ACPI_DMT_BUF12:
    331     case ACPI_DMT_BUF16:
    332     case ACPI_DMT_BUF128:
    333     case ACPI_DMT_PCI_PATH:
    334     case ACPI_DMT_PMTT_VENDOR:
    335 
    336         Type = DT_FIELD_TYPE_BUFFER;
    337         break;
    338 
    339     case ACPI_DMT_GAS:
    340     case ACPI_DMT_HESTNTFY:
    341     case ACPI_DMT_IORTMEM:
    342 
    343         Type = DT_FIELD_TYPE_INLINE_SUBTABLE;
    344         break;
    345 
    346     case ACPI_DMT_UNICODE:
    347 
    348         Type = DT_FIELD_TYPE_UNICODE;
    349         break;
    350 
    351     case ACPI_DMT_UUID:
    352 
    353         Type = DT_FIELD_TYPE_UUID;
    354         break;
    355 
    356     case ACPI_DMT_DEVICE_PATH:
    357 
    358         Type = DT_FIELD_TYPE_DEVICE_PATH;
    359         break;
    360 
    361     case ACPI_DMT_LABEL:
    362 
    363         Type = DT_FIELD_TYPE_LABEL;
    364         break;
    365 
    366     default:
    367 
    368         Type = DT_FIELD_TYPE_INTEGER;
    369         break;
    370     }
    371 
    372     return (Type);
    373 }
    374 
    375 
    376 /******************************************************************************
    377  *
    378  * FUNCTION:    DtGetBufferLength
    379  *
    380  * PARAMETERS:  Buffer              - List of integers,
    381  *                                    for example "10 3A 4F 2E"
    382  *
    383  * RETURN:      Count of integer
    384  *
    385  * DESCRIPTION: Get length of bytes needed to store the integers
    386  *
    387  *****************************************************************************/
    388 
    389 UINT32
    390 DtGetBufferLength (
    391     char                    *Buffer)
    392 {
    393     UINT32                  ByteLength = 0;
    394 
    395 
    396     while (*Buffer)
    397     {
    398         if (*Buffer == ' ')
    399         {
    400             ByteLength++;
    401 
    402             while (*Buffer == ' ')
    403             {
    404                 Buffer++;
    405             }
    406         }
    407 
    408         Buffer++;
    409     }
    410 
    411     return (++ByteLength);
    412 }
    413 
    414 
    415 /******************************************************************************
    416  *
    417  * FUNCTION:    DtGetFieldLength
    418  *
    419  * PARAMETERS:  Field               - Current field
    420  *              Info                - Data table info
    421  *
    422  * RETURN:      Field length
    423  *
    424  * DESCRIPTION: Get length of bytes needed to compile the field
    425  *
    426  * Note: This function must remain in sync with AcpiDmDumpTable.
    427  *
    428  *****************************************************************************/
    429 
    430 UINT32
    431 DtGetFieldLength (
    432     DT_FIELD                *Field,
    433     ACPI_DMTABLE_INFO       *Info)
    434 {
    435     UINT32                  ByteLength = 0;
    436     char                    *Value;
    437 
    438 
    439     /* Length is based upon the opcode for this field in the info table */
    440 
    441     switch (Info->Opcode)
    442     {
    443     case ACPI_DMT_FLAG0:
    444     case ACPI_DMT_FLAG1:
    445     case ACPI_DMT_FLAG2:
    446     case ACPI_DMT_FLAG3:
    447     case ACPI_DMT_FLAG4:
    448     case ACPI_DMT_FLAG5:
    449     case ACPI_DMT_FLAG6:
    450     case ACPI_DMT_FLAG7:
    451     case ACPI_DMT_FLAGS0:
    452     case ACPI_DMT_FLAGS1:
    453     case ACPI_DMT_FLAGS2:
    454     case ACPI_DMT_FLAGS4:
    455     case ACPI_DMT_FLAGS4_0:
    456     case ACPI_DMT_FLAGS4_4:
    457     case ACPI_DMT_FLAGS4_8:
    458     case ACPI_DMT_FLAGS4_12:
    459     case ACPI_DMT_FLAGS16_16:
    460     case ACPI_DMT_LABEL:
    461     case ACPI_DMT_EXTRA_TEXT:
    462 
    463         ByteLength = 0;
    464         break;
    465 
    466     case ACPI_DMT_UINT8:
    467     case ACPI_DMT_CHKSUM:
    468     case ACPI_DMT_SPACEID:
    469     case ACPI_DMT_ACCWIDTH:
    470     case ACPI_DMT_CEDT:
    471     case ACPI_DMT_IVRS:
    472     case ACPI_DMT_IVRS_DE:
    473     case ACPI_DMT_GTDT:
    474     case ACPI_DMT_MADT:
    475     case ACPI_DMT_PCCT:
    476     case ACPI_DMT_PMTT:
    477     case ACPI_DMT_PPTT:
    478     case ACPI_DMT_RGRT:
    479     case ACPI_DMT_SDEV:
    480     case ACPI_DMT_SRAT:
    481     case ACPI_DMT_ASF:
    482     case ACPI_DMT_HESTNTYP:
    483     case ACPI_DMT_FADTPM:
    484     case ACPI_DMT_EINJACT:
    485     case ACPI_DMT_EINJINST:
    486     case ACPI_DMT_ERSTACT:
    487     case ACPI_DMT_ERSTINST:
    488     case ACPI_DMT_DMAR_SCOPE:
    489     case ACPI_DMT_VIOT:
    490 
    491         ByteLength = 1;
    492         break;
    493 
    494     case ACPI_DMT_UINT16:
    495     case ACPI_DMT_DMAR:
    496     case ACPI_DMT_HEST:
    497     case ACPI_DMT_HMAT:
    498     case ACPI_DMT_NFIT:
    499     case ACPI_DMT_PCI_PATH:
    500     case ACPI_DMT_PHAT:
    501 
    502         ByteLength = 2;
    503         break;
    504 
    505     case ACPI_DMT_UINT24:
    506 
    507         ByteLength = 3;
    508         break;
    509 
    510     case ACPI_DMT_UINT32:
    511     case ACPI_DMT_NAME4:
    512     case ACPI_DMT_SIG:
    513     case ACPI_DMT_LPIT:
    514     case ACPI_DMT_TPM2:
    515 
    516         ByteLength = 4;
    517         break;
    518 
    519     case ACPI_DMT_UINT40:
    520 
    521         ByteLength = 5;
    522         break;
    523 
    524     case ACPI_DMT_UINT48:
    525     case ACPI_DMT_NAME6:
    526 
    527         ByteLength = 6;
    528         break;
    529 
    530     case ACPI_DMT_UINT56:
    531     case ACPI_DMT_BUF7:
    532 
    533         ByteLength = 7;
    534         break;
    535 
    536     case ACPI_DMT_UINT64:
    537     case ACPI_DMT_NAME8:
    538 
    539         ByteLength = 8;
    540         break;
    541 
    542     case ACPI_DMT_STRING:
    543 
    544         Value = DtGetFieldValue (Field);
    545         if (Value)
    546         {
    547             ByteLength = strlen (Value) + 1;
    548         }
    549         else
    550         {   /* At this point, this is a fatal error */
    551 
    552             snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
    553             DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
    554             return (0);
    555         }
    556         break;
    557 
    558     case ACPI_DMT_IVRS_UNTERMINATED_STRING:
    559 
    560         Value = DtGetFieldValue (Field);
    561         if (Value)
    562         {
    563             ByteLength = strlen (Value);
    564         }
    565         else
    566         {   /* At this point, this is a fatal error */
    567 
    568             sprintf (AslGbl_MsgBuffer, "Expected \"%s\"", Info->Name);
    569             DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
    570             return (0);
    571         }
    572         break;
    573 
    574     case ACPI_DMT_GAS:
    575 
    576         ByteLength = sizeof (ACPI_GENERIC_ADDRESS);
    577         break;
    578 
    579     case ACPI_DMT_HESTNTFY:
    580 
    581         ByteLength = sizeof (ACPI_HEST_NOTIFY);
    582         break;
    583 
    584     case ACPI_DMT_IORTMEM:
    585 
    586         ByteLength = sizeof (ACPI_IORT_MEMORY_ACCESS);
    587         break;
    588 
    589     case ACPI_DMT_BUFFER:
    590     case ACPI_DMT_RAW_BUFFER:
    591     case ACPI_DMT_PMTT_VENDOR:
    592 
    593         Value = DtGetFieldValue (Field);
    594         if (Value)
    595         {
    596             ByteLength = DtGetBufferLength (Value);
    597         }
    598         else
    599         {   /* At this point, this is a fatal error */
    600 
    601             snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
    602             DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
    603             return (0);
    604         }
    605         break;
    606 
    607     case ACPI_DMT_BUF10:
    608 
    609         ByteLength = 10;
    610         break;
    611 
    612     case ACPI_DMT_BUF12:
    613 
    614         ByteLength = 12;
    615         break;
    616 
    617     case ACPI_DMT_BUF16:
    618     case ACPI_DMT_UUID:
    619 
    620         ByteLength = 16;
    621         break;
    622 
    623     case ACPI_DMT_BUF128:
    624 
    625         ByteLength = 128;
    626         break;
    627 
    628     case ACPI_DMT_UNICODE:
    629 
    630         Value = DtGetFieldValue (Field);
    631 
    632         /* TBD: error if Value is NULL? (as below?) */
    633 
    634         ByteLength = (strlen (Value) + 1) * sizeof(UINT16);
    635         break;
    636 
    637     default:
    638 
    639         DtFatal (ASL_MSG_COMPILER_INTERNAL, Field, "Invalid table opcode");
    640         return (0);
    641     }
    642 
    643     return (ByteLength);
    644 }
    645 
    646 
    647 /******************************************************************************
    648  *
    649  * FUNCTION:    DtSum
    650  *
    651  * PARAMETERS:  DT_WALK_CALLBACK:
    652  *              Subtable            - Subtable
    653  *              Context             - Unused
    654  *              ReturnValue         - Store the checksum of subtable
    655  *
    656  * RETURN:      Status
    657  *
    658  * DESCRIPTION: Get the checksum of subtable
    659  *
    660  *****************************************************************************/
    661 
    662 static void
    663 DtSum (
    664     DT_SUBTABLE             *Subtable,
    665     void                    *Context,
    666     void                    *ReturnValue)
    667 {
    668     UINT8                   Checksum;
    669     UINT8                   *Sum = ReturnValue;
    670 
    671 
    672     Checksum = AcpiTbChecksum (Subtable->Buffer, Subtable->Length);
    673     *Sum = (UINT8) (*Sum + Checksum);
    674 }
    675 
    676 
    677 /******************************************************************************
    678  *
    679  * FUNCTION:    DtSetTableChecksum
    680  *
    681  * PARAMETERS:  ChecksumPointer     - Where to return the checksum
    682  *
    683  * RETURN:      None
    684  *
    685  * DESCRIPTION: Set checksum of the whole data table into the checksum field
    686  *
    687  *****************************************************************************/
    688 
    689 void
    690 DtSetTableChecksum (
    691     UINT8                   *ChecksumPointer)
    692 {
    693     UINT8                   Checksum = 0;
    694     UINT8                   OldSum;
    695 
    696 
    697     DtWalkTableTree (AslGbl_RootTable, DtSum, NULL, &Checksum);
    698 
    699     OldSum = *ChecksumPointer;
    700     Checksum = (UINT8) (Checksum - OldSum);
    701 
    702     /* Compute the final checksum */
    703 
    704     Checksum = (UINT8) (0 - Checksum);
    705     *ChecksumPointer = Checksum;
    706 }
    707 
    708 
    709 /******************************************************************************
    710  *
    711  * FUNCTION:    DtSetTableLength
    712  *
    713  * PARAMETERS:  None
    714  *
    715  * RETURN:      None
    716  *
    717  * DESCRIPTION: Walk the subtables and set all the length fields
    718  *
    719  *****************************************************************************/
    720 
    721 void
    722 DtSetTableLength (
    723     void)
    724 {
    725     DT_SUBTABLE             *ParentTable;
    726     DT_SUBTABLE             *ChildTable;
    727 
    728 
    729     ParentTable = AslGbl_RootTable;
    730     ChildTable = NULL;
    731 
    732     if (!ParentTable)
    733     {
    734         return;
    735     }
    736 
    737     DtSetSubtableLength (ParentTable);
    738 
    739     while (1)
    740     {
    741         ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
    742         if (ChildTable)
    743         {
    744             if (ChildTable->LengthField)
    745             {
    746                 DtSetSubtableLength (ChildTable);
    747             }
    748 
    749             if (ChildTable->Child)
    750             {
    751                 ParentTable = ChildTable;
    752                 ChildTable = NULL;
    753             }
    754             else
    755             {
    756                 ParentTable->TotalLength += ChildTable->TotalLength;
    757                 if (ParentTable->LengthField)
    758                 {
    759                     DtSetSubtableLength (ParentTable);
    760                 }
    761             }
    762         }
    763         else
    764         {
    765             ChildTable = ParentTable;
    766 
    767             if (ChildTable == AslGbl_RootTable)
    768             {
    769                 break;
    770             }
    771 
    772             ParentTable = DtGetParentSubtable (ParentTable);
    773 
    774             ParentTable->TotalLength += ChildTable->TotalLength;
    775             if (ParentTable->LengthField)
    776             {
    777                 DtSetSubtableLength (ParentTable);
    778             }
    779         }
    780     }
    781 }
    782 
    783 
    784 /******************************************************************************
    785  *
    786  * FUNCTION:    DtWalkTableTree
    787  *
    788  * PARAMETERS:  StartTable          - Subtable in the tree where walking begins
    789  *              UserFunction        - Called during the walk
    790  *              Context             - Passed to user function
    791  *              ReturnValue         - The return value of UserFunction
    792  *
    793  * RETURN:      None
    794  *
    795  * DESCRIPTION: Performs a depth-first walk of the subtable tree
    796  *
    797  *****************************************************************************/
    798 
    799 void
    800 DtWalkTableTree (
    801     DT_SUBTABLE             *StartTable,
    802     DT_WALK_CALLBACK        UserFunction,
    803     void                    *Context,
    804     void                    *ReturnValue)
    805 {
    806     DT_SUBTABLE             *ParentTable;
    807     DT_SUBTABLE             *ChildTable;
    808 
    809 
    810     ParentTable = StartTable;
    811     ChildTable = NULL;
    812 
    813     if (!ParentTable)
    814     {
    815         return;
    816     }
    817 
    818     UserFunction (ParentTable, Context, ReturnValue);
    819 
    820     while (1)
    821     {
    822         ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
    823         if (ChildTable)
    824         {
    825             UserFunction (ChildTable, Context, ReturnValue);
    826 
    827             if (ChildTable->Child)
    828             {
    829                 ParentTable = ChildTable;
    830                 ChildTable = NULL;
    831             }
    832         }
    833         else
    834         {
    835             ChildTable = ParentTable;
    836             if (ChildTable == AslGbl_RootTable)
    837             {
    838                 break;
    839             }
    840 
    841             ParentTable = DtGetParentSubtable (ParentTable);
    842 
    843             if (ChildTable->Peer == StartTable)
    844             {
    845                 break;
    846             }
    847         }
    848     }
    849 }
    850