Home | History | Annotate | Line # | Download | only in compiler
dtutils.c revision 1.19
      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_BUF18:
    333     case ACPI_DMT_BUF128:
    334     case ACPI_DMT_PCI_PATH:
    335     case ACPI_DMT_PMTT_VENDOR:
    336 
    337         Type = DT_FIELD_TYPE_BUFFER;
    338         break;
    339 
    340     case ACPI_DMT_GAS:
    341     case ACPI_DMT_HESTNTFY:
    342     case ACPI_DMT_IORTMEM:
    343 
    344         Type = DT_FIELD_TYPE_INLINE_SUBTABLE;
    345         break;
    346 
    347     case ACPI_DMT_UNICODE:
    348     case ACPI_DMT_WPBT_UNICODE:
    349 
    350         Type = DT_FIELD_TYPE_UNICODE;
    351         break;
    352 
    353     case ACPI_DMT_UUID:
    354 
    355         Type = DT_FIELD_TYPE_UUID;
    356         break;
    357 
    358     case ACPI_DMT_DEVICE_PATH:
    359 
    360         Type = DT_FIELD_TYPE_DEVICE_PATH;
    361         break;
    362 
    363     case ACPI_DMT_LABEL:
    364 
    365         Type = DT_FIELD_TYPE_LABEL;
    366         break;
    367 
    368     default:
    369 
    370         Type = DT_FIELD_TYPE_INTEGER;
    371         break;
    372     }
    373 
    374     return (Type);
    375 }
    376 
    377 
    378 /******************************************************************************
    379  *
    380  * FUNCTION:    DtGetBufferLength
    381  *
    382  * PARAMETERS:  Buffer              - List of integers,
    383  *                                    for example "10 3A 4F 2E"
    384  *
    385  * RETURN:      Count of integer
    386  *
    387  * DESCRIPTION: Get length of bytes needed to store the integers
    388  *
    389  *****************************************************************************/
    390 
    391 UINT32
    392 DtGetBufferLength (
    393     char                    *Buffer)
    394 {
    395     UINT32                  ByteLength = 0;
    396 
    397 
    398     while (*Buffer)
    399     {
    400         if (*Buffer == ' ')
    401         {
    402             ByteLength++;
    403 
    404             while (*Buffer == ' ')
    405             {
    406                 Buffer++;
    407             }
    408         }
    409 
    410         Buffer++;
    411     }
    412 
    413     return (++ByteLength);
    414 }
    415 
    416 
    417 /******************************************************************************
    418  *
    419  * FUNCTION:    DtGetFieldLength
    420  *
    421  * PARAMETERS:  Field               - Current field
    422  *              Info                - Data table info
    423  *
    424  * RETURN:      Field length
    425  *
    426  * DESCRIPTION: Get length of bytes needed to compile the field
    427  *
    428  * Note: This function must remain in sync with AcpiDmDumpTable.
    429  *
    430  *****************************************************************************/
    431 
    432 UINT32
    433 DtGetFieldLength (
    434     DT_FIELD                *Field,
    435     ACPI_DMTABLE_INFO       *Info)
    436 {
    437     UINT32                  ByteLength = 0;
    438     char                    *Value;
    439 
    440 
    441     /* Length is based upon the opcode for this field in the info table */
    442 
    443     switch (Info->Opcode)
    444     {
    445     case ACPI_DMT_FLAG0:
    446     case ACPI_DMT_FLAG1:
    447     case ACPI_DMT_FLAG2:
    448     case ACPI_DMT_FLAG3:
    449     case ACPI_DMT_FLAG4:
    450     case ACPI_DMT_FLAG5:
    451     case ACPI_DMT_FLAG6:
    452     case ACPI_DMT_FLAG7:
    453     case ACPI_DMT_FLAGS0:
    454     case ACPI_DMT_FLAGS1:
    455     case ACPI_DMT_FLAGS2:
    456     case ACPI_DMT_FLAGS4:
    457     case ACPI_DMT_FLAGS4_0:
    458     case ACPI_DMT_FLAGS4_4:
    459     case ACPI_DMT_FLAGS4_8:
    460     case ACPI_DMT_FLAGS4_12:
    461     case ACPI_DMT_FLAGS16_16:
    462     case ACPI_DMT_LABEL:
    463     case ACPI_DMT_EXTRA_TEXT:
    464 
    465         ByteLength = 0;
    466         break;
    467 
    468     case ACPI_DMT_UINT8:
    469     case ACPI_DMT_CHKSUM:
    470     case ACPI_DMT_SPACEID:
    471     case ACPI_DMT_ACCWIDTH:
    472     case ACPI_DMT_CEDT:
    473     case ACPI_DMT_IVRS:
    474     case ACPI_DMT_IVRS_DE:
    475     case ACPI_DMT_GTDT:
    476     case ACPI_DMT_MADT:
    477     case ACPI_DMT_NHLT1:
    478     case ACPI_DMT_NHLT1a:
    479     case ACPI_DMT_NHLT1b:
    480     case ACPI_DMT_NHLT1c:
    481     case ACPI_DMT_NHLT1d:
    482     case ACPI_DMT_NHLT1f:
    483     case ACPI_DMT_PCCT:
    484     case ACPI_DMT_PMTT:
    485     case ACPI_DMT_PPTT:
    486     case ACPI_DMT_RGRT:
    487     case ACPI_DMT_SDEV:
    488     case ACPI_DMT_SRAT:
    489     case ACPI_DMT_AEST:
    490     case ACPI_DMT_AEST_RES:
    491     case ACPI_DMT_AEST_XFACE:
    492     case ACPI_DMT_AEST_XRUPT:
    493     case ACPI_DMT_ASF:
    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_UINT16:
    507     case ACPI_DMT_DMAR:
    508     case ACPI_DMT_HEST:
    509     case ACPI_DMT_HMAT:
    510     case ACPI_DMT_NFIT:
    511     case ACPI_DMT_NHLT1e:
    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_BUF128:
    644 
    645         ByteLength = 128;
    646         break;
    647 
    648     case ACPI_DMT_UNICODE:
    649     case ACPI_DMT_WPBT_UNICODE:
    650 
    651         Value = DtGetFieldValue (Field);
    652 
    653         /* TBD: error if Value is NULL? (as below?) */
    654 
    655         ByteLength = (strlen (Value) + 1) * sizeof (UINT16);
    656         break;
    657 
    658     default:
    659 
    660         DtFatal (ASL_MSG_COMPILER_INTERNAL, Field, "Invalid table opcode");
    661         return (0);
    662     }
    663 
    664     return (ByteLength);
    665 }
    666 
    667 
    668 /******************************************************************************
    669  *
    670  * FUNCTION:    DtSum
    671  *
    672  * PARAMETERS:  DT_WALK_CALLBACK:
    673  *              Subtable            - Subtable
    674  *              Context             - Unused
    675  *              ReturnValue         - Store the checksum of subtable
    676  *
    677  * RETURN:      Status
    678  *
    679  * DESCRIPTION: Get the checksum of subtable
    680  *
    681  *****************************************************************************/
    682 
    683 static void
    684 DtSum (
    685     DT_SUBTABLE             *Subtable,
    686     void                    *Context,
    687     void                    *ReturnValue)
    688 {
    689     UINT8                   Checksum;
    690     UINT8                   *Sum = ReturnValue;
    691 
    692 
    693     Checksum = AcpiTbChecksum (Subtable->Buffer, Subtable->Length);
    694     *Sum = (UINT8) (*Sum + Checksum);
    695 }
    696 
    697 
    698 /******************************************************************************
    699  *
    700  * FUNCTION:    DtSetTableChecksum
    701  *
    702  * PARAMETERS:  ChecksumPointer     - Where to return the checksum
    703  *
    704  * RETURN:      None
    705  *
    706  * DESCRIPTION: Set checksum of the whole data table into the checksum field
    707  *
    708  *****************************************************************************/
    709 
    710 void
    711 DtSetTableChecksum (
    712     UINT8                   *ChecksumPointer)
    713 {
    714     UINT8                   Checksum = 0;
    715     UINT8                   OldSum;
    716 
    717 
    718     DtWalkTableTree (AslGbl_RootTable, DtSum, NULL, &Checksum);
    719 
    720     OldSum = *ChecksumPointer;
    721     Checksum = (UINT8) (Checksum - OldSum);
    722 
    723     /* Compute the final checksum */
    724 
    725     Checksum = (UINT8) (0 - Checksum);
    726     *ChecksumPointer = Checksum;
    727 }
    728 
    729 
    730 /******************************************************************************
    731  *
    732  * FUNCTION:    DtSetTableLength
    733  *
    734  * PARAMETERS:  None
    735  *
    736  * RETURN:      None
    737  *
    738  * DESCRIPTION: Walk the subtables and set all the length fields
    739  *
    740  *****************************************************************************/
    741 
    742 void
    743 DtSetTableLength (
    744     void)
    745 {
    746     DT_SUBTABLE             *ParentTable;
    747     DT_SUBTABLE             *ChildTable;
    748 
    749 
    750     ParentTable = AslGbl_RootTable;
    751     ChildTable = NULL;
    752 
    753     if (!ParentTable)
    754     {
    755         return;
    756     }
    757 
    758     DtSetSubtableLength (ParentTable);
    759 
    760     while (1)
    761     {
    762         ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
    763         if (ChildTable)
    764         {
    765             if (ChildTable->LengthField)
    766             {
    767                 DtSetSubtableLength (ChildTable);
    768             }
    769 
    770             if (ChildTable->Child)
    771             {
    772                 ParentTable = ChildTable;
    773                 ChildTable = NULL;
    774             }
    775             else
    776             {
    777                 ParentTable->TotalLength += ChildTable->TotalLength;
    778                 if (ParentTable->LengthField)
    779                 {
    780                     DtSetSubtableLength (ParentTable);
    781                 }
    782             }
    783         }
    784         else
    785         {
    786             ChildTable = ParentTable;
    787 
    788             if (ChildTable == AslGbl_RootTable)
    789             {
    790                 break;
    791             }
    792 
    793             ParentTable = DtGetParentSubtable (ParentTable);
    794 
    795             ParentTable->TotalLength += ChildTable->TotalLength;
    796             if (ParentTable->LengthField)
    797             {
    798                 DtSetSubtableLength (ParentTable);
    799             }
    800         }
    801     }
    802 }
    803 
    804 
    805 /******************************************************************************
    806  *
    807  * FUNCTION:    DtWalkTableTree
    808  *
    809  * PARAMETERS:  StartTable          - Subtable in the tree where walking begins
    810  *              UserFunction        - Called during the walk
    811  *              Context             - Passed to user function
    812  *              ReturnValue         - The return value of UserFunction
    813  *
    814  * RETURN:      None
    815  *
    816  * DESCRIPTION: Performs a depth-first walk of the subtable tree
    817  *
    818  *****************************************************************************/
    819 
    820 void
    821 DtWalkTableTree (
    822     DT_SUBTABLE             *StartTable,
    823     DT_WALK_CALLBACK        UserFunction,
    824     void                    *Context,
    825     void                    *ReturnValue)
    826 {
    827     DT_SUBTABLE             *ParentTable;
    828     DT_SUBTABLE             *ChildTable;
    829 
    830 
    831     ParentTable = StartTable;
    832     ChildTable = NULL;
    833 
    834     if (!ParentTable)
    835     {
    836         return;
    837     }
    838 
    839     UserFunction (ParentTable, Context, ReturnValue);
    840 
    841     while (1)
    842     {
    843         ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
    844         if (ChildTable)
    845         {
    846             UserFunction (ChildTable, Context, ReturnValue);
    847 
    848             if (ChildTable->Child)
    849             {
    850                 ParentTable = ChildTable;
    851                 ChildTable = NULL;
    852             }
    853         }
    854         else
    855         {
    856             ChildTable = ParentTable;
    857             if (ChildTable == AslGbl_RootTable)
    858             {
    859                 break;
    860             }
    861 
    862             ParentTable = DtGetParentSubtable (ParentTable);
    863 
    864             if (ChildTable->Peer == StartTable)
    865             {
    866                 break;
    867             }
    868         }
    869     }
    870 }
    871