1/******************************************************************************
2 *
3 * Module Name: tbutils - ACPI Table utilities
4 *
5 *****************************************************************************/
6
7/******************************************************************************
8 *
9 * 1. Copyright Notice
10 *
11 * Some or all of this work - Copyright (c) 1999 - 2023, Intel Corp.
12 * All rights reserved.
13 *
14 * 2. License
15 *
16 * 2.1. This is your license from Intel Corp. under its intellectual property
17 * rights. You may have additional license terms from the party that provided
18 * you this software, covering your right to use that party's intellectual
19 * property rights.
20 *
21 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22 * copy of the source code appearing in this file ("Covered Code") an
23 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24 * base code distributed originally by Intel ("Original Intel Code") to copy,
25 * make derivatives, distribute, use and display any portion of the Covered
26 * Code in any form, with the right to sublicense such rights; and
27 *
28 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29 * license (with the right to sublicense), under only those claims of Intel
30 * patents that are infringed by the Original Intel Code, to make, use, sell,
31 * offer to sell, and import the Covered Code and derivative works thereof
32 * solely to the minimum extent necessary to exercise the above copyright
33 * license, and in no event shall the patent license extend to any additions
34 * to or modifications of the Original Intel Code. No other license or right
35 * is granted directly or by implication, estoppel or otherwise;
36 *
37 * The above copyright and patent license is granted only if the following
38 * conditions are met:
39 *
40 * 3. Conditions
41 *
42 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43 * Redistribution of source code of any substantial portion of the Covered
44 * Code or modification with rights to further distribute source must include
45 * the above Copyright Notice, the above License, this list of Conditions,
46 * and the following Disclaimer and Export Compliance provision. In addition,
47 * Licensee must cause all Covered Code to which Licensee contributes to
48 * contain a file documenting the changes Licensee made to create that Covered
49 * Code and the date of any change. Licensee must include in that file the
50 * documentation of any changes made by any predecessor Licensee. Licensee
51 * must include a prominent statement that the modification is derived,
52 * directly or indirectly, from Original Intel Code.
53 *
54 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55 * Redistribution of source code of any substantial portion of the Covered
56 * Code or modification without rights to further distribute source must
57 * include the following Disclaimer and Export Compliance provision in the
58 * documentation and/or other materials provided with distribution. In
59 * addition, Licensee may not authorize further sublicense of source of any
60 * portion of the Covered Code, and must include terms to the effect that the
61 * license from Licensee to its licensee is limited to the intellectual
62 * property embodied in the software Licensee provides to its licensee, and
63 * not to intellectual property embodied in modifications its licensee may
64 * make.
65 *
66 * 3.3. Redistribution of Executable. Redistribution in executable form of any
67 * substantial portion of the Covered Code or modification must reproduce the
68 * above Copyright Notice, and the following Disclaimer and Export Compliance
69 * provision in the documentation and/or other materials provided with the
70 * distribution.
71 *
72 * 3.4. Intel retains all right, title, and interest in and to the Original
73 * Intel Code.
74 *
75 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76 * Intel shall be used in advertising or otherwise to promote the sale, use or
77 * other dealings in products derived from or relating to the Covered Code
78 * without prior written authorization from Intel.
79 *
80 * 4. Disclaimer and Export Compliance
81 *
82 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
88 * PARTICULAR PURPOSE.
89 *
90 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
97 * LIMITED REMEDY.
98 *
99 * 4.3. Licensee shall not export, either directly or indirectly, any of this
100 * software or system incorporating such software without first obtaining any
101 * required license or other approval from the U. S. Department of Commerce or
102 * any other agency or department of the United States Government. In the
103 * event Licensee exports any such software from the United States or
104 * re-exports any such software from a foreign destination, Licensee shall
105 * ensure that the distribution and export/re-export of the software is in
106 * compliance with all laws, regulations, orders, or other restrictions of the
107 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108 * any of its subsidiaries will export/re-export any technical data, process,
109 * software, or service, directly or indirectly, to any country for which the
110 * United States government or any agency thereof requires an export license,
111 * other governmental approval, or letter of assurance, without first obtaining
112 * such license, approval or letter.
113 *
114 *****************************************************************************
115 *
116 * Alternatively, you may choose to be licensed under the terms of the
117 * following license:
118 *
119 * Redistribution and use in source and binary forms, with or without
120 * modification, are permitted provided that the following conditions
121 * are met:
122 * 1. Redistributions of source code must retain the above copyright
123 *    notice, this list of conditions, and the following disclaimer,
124 *    without modification.
125 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
126 *    substantially similar to the "NO WARRANTY" disclaimer below
127 *    ("Disclaimer") and any redistribution must be conditioned upon
128 *    including a substantially similar Disclaimer requirement for further
129 *    binary redistribution.
130 * 3. Neither the names of the above-listed copyright holders nor the names
131 *    of any contributors may be used to endorse or promote products derived
132 *    from this software without specific prior written permission.
133 *
134 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
135 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
136 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
137 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
138 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
139 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
140 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
141 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
142 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
143 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
144 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
145 *
146 * Alternatively, you may choose to be licensed under the terms of the
147 * GNU General Public License ("GPL") version 2 as published by the Free
148 * Software Foundation.
149 *
150 *****************************************************************************/
151
152#include "acpi.h"
153#include "accommon.h"
154#include "actables.h"
155
156#define _COMPONENT          ACPI_TABLES
157        ACPI_MODULE_NAME    ("tbutils")
158
159
160/* Local prototypes */
161
162static ACPI_PHYSICAL_ADDRESS
163AcpiTbGetRootTableEntry (
164    UINT8                   *TableEntry,
165    UINT32                  TableEntrySize);
166
167
168#if (!ACPI_REDUCED_HARDWARE)
169/*******************************************************************************
170 *
171 * FUNCTION:    AcpiTbInitializeFacs
172 *
173 * PARAMETERS:  None
174 *
175 * RETURN:      Status
176 *
177 * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
178 *              for accessing the Global Lock and Firmware Waking Vector
179 *
180 ******************************************************************************/
181
182ACPI_STATUS
183AcpiTbInitializeFacs (
184    void)
185{
186    ACPI_TABLE_FACS         *Facs;
187
188
189    /* If Hardware Reduced flag is set, there is no FACS */
190
191    if (AcpiGbl_ReducedHardware)
192    {
193        AcpiGbl_FACS = NULL;
194        return (AE_OK);
195    }
196    else if (AcpiGbl_FADT.XFacs &&
197         (!AcpiGbl_FADT.Facs || !AcpiGbl_Use32BitFacsAddresses))
198    {
199        (void) AcpiGetTableByIndex (AcpiGbl_XFacsIndex,
200            ACPI_CAST_INDIRECT_PTR (ACPI_TABLE_HEADER, &Facs));
201        AcpiGbl_FACS = Facs;
202    }
203    else if (AcpiGbl_FADT.Facs)
204    {
205        (void) AcpiGetTableByIndex (AcpiGbl_FacsIndex,
206            ACPI_CAST_INDIRECT_PTR (ACPI_TABLE_HEADER, &Facs));
207        AcpiGbl_FACS = Facs;
208    }
209
210    /* If there is no FACS, just continue. There was already an error msg */
211
212    return (AE_OK);
213}
214#endif /* !ACPI_REDUCED_HARDWARE */
215
216
217/*******************************************************************************
218 *
219 * FUNCTION:    AcpiTbCheckDsdtHeader
220 *
221 * PARAMETERS:  None
222 *
223 * RETURN:      None
224 *
225 * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
226 *              if the DSDT has been replaced from outside the OS and/or if
227 *              the DSDT header has been corrupted.
228 *
229 ******************************************************************************/
230
231void
232AcpiTbCheckDsdtHeader (
233    void)
234{
235
236    /* Compare original length and checksum to current values */
237
238    if (AcpiGbl_OriginalDsdtHeader.Length != AcpiGbl_DSDT->Length ||
239        AcpiGbl_OriginalDsdtHeader.Checksum != AcpiGbl_DSDT->Checksum)
240    {
241        ACPI_BIOS_ERROR ((AE_INFO,
242            "The DSDT has been corrupted or replaced - "
243            "old, new headers below"));
244
245        AcpiTbPrintTableHeader (0, &AcpiGbl_OriginalDsdtHeader);
246        AcpiTbPrintTableHeader (0, AcpiGbl_DSDT);
247
248        /* Disable further error messages */
249
250        AcpiGbl_OriginalDsdtHeader.Length = AcpiGbl_DSDT->Length;
251        AcpiGbl_OriginalDsdtHeader.Checksum = AcpiGbl_DSDT->Checksum;
252    }
253}
254
255
256/*******************************************************************************
257 *
258 * FUNCTION:    AcpiTbCopyDsdt
259 *
260 * PARAMETERS:  TableIndex          - Index of installed table to copy
261 *
262 * RETURN:      The copied DSDT
263 *
264 * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
265 *              Some very bad BIOSs are known to either corrupt the DSDT or
266 *              install a new, bad DSDT. This copy works around the problem.
267 *
268 ******************************************************************************/
269
270ACPI_TABLE_HEADER *
271AcpiTbCopyDsdt (
272    UINT32                  TableIndex)
273{
274    ACPI_TABLE_HEADER       *NewTable;
275    ACPI_TABLE_DESC         *TableDesc;
276
277
278    TableDesc = &AcpiGbl_RootTableList.Tables[TableIndex];
279
280    NewTable = ACPI_ALLOCATE (TableDesc->Length);
281    if (!NewTable)
282    {
283        ACPI_ERROR ((AE_INFO, "Could not copy DSDT of length 0x%X",
284            TableDesc->Length));
285        return (NULL);
286    }
287
288    memcpy (NewTable, TableDesc->Pointer, TableDesc->Length);
289    AcpiTbUninstallTable (TableDesc);
290
291    AcpiTbInitTableDescriptor (
292        &AcpiGbl_RootTableList.Tables[AcpiGbl_DsdtIndex],
293        ACPI_PTR_TO_PHYSADDR (NewTable),
294        ACPI_TABLE_ORIGIN_INTERNAL_VIRTUAL, NewTable);
295
296    ACPI_INFO ((
297        "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
298        NewTable->Length));
299
300    return (NewTable);
301}
302
303
304/*******************************************************************************
305 *
306 * FUNCTION:    AcpiTbGetRootTableEntry
307 *
308 * PARAMETERS:  TableEntry          - Pointer to the RSDT/XSDT table entry
309 *              TableEntrySize      - sizeof 32 or 64 (RSDT or XSDT)
310 *
311 * RETURN:      Physical address extracted from the root table
312 *
313 * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
314 *              both 32-bit and 64-bit platforms
315 *
316 * NOTE:        ACPI_PHYSICAL_ADDRESS is 32-bit on 32-bit platforms, 64-bit on
317 *              64-bit platforms.
318 *
319 ******************************************************************************/
320
321static ACPI_PHYSICAL_ADDRESS
322AcpiTbGetRootTableEntry (
323    UINT8                   *TableEntry,
324    UINT32                  TableEntrySize)
325{
326    UINT32                  Address32;
327    UINT64                  Address64;
328
329
330    /*
331     * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
332     * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
333     */
334    if (TableEntrySize == ACPI_RSDT_ENTRY_SIZE)
335    {
336        /*
337         * 32-bit platform, RSDT: Return 32-bit table entry
338         * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
339         */
340        ACPI_MOVE_32_TO_32(&Address32, TableEntry);
341        return Address32;
342    }
343    else
344    {
345        /*
346         * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
347         * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
348         *  return 64-bit
349         */
350        ACPI_MOVE_64_TO_64 (&Address64, TableEntry);
351
352#if ACPI_MACHINE_WIDTH == 32
353        if (Address64 > ACPI_UINT32_MAX)
354        {
355            /* Will truncate 64-bit address to 32 bits, issue warning */
356
357            ACPI_BIOS_WARNING ((AE_INFO,
358                "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
359                " truncating",
360                ACPI_FORMAT_UINT64 (Address64)));
361        }
362#endif
363        return ((ACPI_PHYSICAL_ADDRESS) (Address64));
364    }
365}
366
367
368/*******************************************************************************
369 *
370 * FUNCTION:    AcpiTbParseRootTable
371 *
372 * PARAMETERS:  RsdpAddress         - Pointer to the RSDP
373 *
374 * RETURN:      Status
375 *
376 * DESCRIPTION: This function is called to parse the Root System Description
377 *              Table (RSDT or XSDT)
378 *
379 * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
380 *              be mapped and cannot be copied because it contains the actual
381 *              memory location of the ACPI Global Lock.
382 *
383 ******************************************************************************/
384
385ACPI_STATUS ACPI_INIT_FUNCTION
386AcpiTbParseRootTable (
387    ACPI_PHYSICAL_ADDRESS   RsdpAddress)
388{
389    ACPI_TABLE_RSDP         *Rsdp;
390    UINT32                  TableEntrySize;
391    UINT32                  i;
392    UINT32                  TableCount;
393    ACPI_TABLE_HEADER       *Table;
394    ACPI_PHYSICAL_ADDRESS   Address;
395    UINT32                  Length;
396    UINT8                   *TableEntry;
397    ACPI_STATUS             Status;
398    UINT32                  TableIndex;
399
400
401    ACPI_FUNCTION_TRACE (TbParseRootTable);
402
403
404    /* Map the entire RSDP and extract the address of the RSDT or XSDT */
405
406    Rsdp = AcpiOsMapMemory (RsdpAddress, sizeof (ACPI_TABLE_RSDP));
407    if (!Rsdp)
408    {
409        return_ACPI_STATUS (AE_NO_MEMORY);
410    }
411
412    AcpiTbPrintTableHeader (RsdpAddress,
413        ACPI_CAST_PTR (ACPI_TABLE_HEADER, Rsdp));
414
415    /* Use XSDT if present and not overridden. Otherwise, use RSDT */
416
417    if ((Rsdp->Revision > 1) &&
418        Rsdp->XsdtPhysicalAddress &&
419        !AcpiGbl_DoNotUseXsdt)
420    {
421        /*
422         * RSDP contains an XSDT (64-bit physical addresses). We must use
423         * the XSDT if the revision is > 1 and the XSDT pointer is present,
424         * as per the ACPI specification.
425         */
426        Address = (ACPI_PHYSICAL_ADDRESS) Rsdp->XsdtPhysicalAddress;
427        TableEntrySize = ACPI_XSDT_ENTRY_SIZE;
428    }
429    else
430    {
431        /* Root table is an RSDT (32-bit physical addresses) */
432
433        Address = (ACPI_PHYSICAL_ADDRESS) Rsdp->RsdtPhysicalAddress;
434        TableEntrySize = ACPI_RSDT_ENTRY_SIZE;
435    }
436
437    /*
438     * It is not possible to map more than one entry in some environments,
439     * so unmap the RSDP here before mapping other tables
440     */
441    AcpiOsUnmapMemory (Rsdp, sizeof (ACPI_TABLE_RSDP));
442
443    /* Map the RSDT/XSDT table header to get the full table length */
444
445    Table = AcpiOsMapMemory (Address, sizeof (ACPI_TABLE_HEADER));
446    if (!Table)
447    {
448        return_ACPI_STATUS (AE_NO_MEMORY);
449    }
450
451    AcpiTbPrintTableHeader (Address, Table);
452
453    /*
454     * Validate length of the table, and map entire table.
455     * Minimum length table must contain at least one entry.
456     */
457    Length = Table->Length;
458    AcpiOsUnmapMemory (Table, sizeof (ACPI_TABLE_HEADER));
459
460    if (Length < (sizeof (ACPI_TABLE_HEADER) + TableEntrySize))
461    {
462        ACPI_BIOS_ERROR ((AE_INFO,
463            "Invalid table length 0x%X in RSDT/XSDT", Length));
464        return_ACPI_STATUS (AE_INVALID_TABLE_LENGTH);
465    }
466
467    Table = AcpiOsMapMemory (Address, Length);
468    if (!Table)
469    {
470        return_ACPI_STATUS (AE_NO_MEMORY);
471    }
472
473    /* Validate the root table checksum */
474
475    Status = AcpiUtVerifyChecksum (Table, Length);
476    if (ACPI_FAILURE (Status))
477    {
478        AcpiOsUnmapMemory (Table, Length);
479        return_ACPI_STATUS (Status);
480    }
481
482    /* Get the number of entries and pointer to first entry */
483
484    TableCount = (UINT32) ((Table->Length - sizeof (ACPI_TABLE_HEADER)) /
485        TableEntrySize);
486    TableEntry = ACPI_ADD_PTR (UINT8, Table, sizeof (ACPI_TABLE_HEADER));
487
488    /* Initialize the root table array from the RSDT/XSDT */
489
490    for (i = 0; i < TableCount; i++)
491    {
492        /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */
493
494        Address = AcpiTbGetRootTableEntry (TableEntry, TableEntrySize);
495
496        /* Skip NULL entries in RSDT/XSDT */
497
498        if (!Address)
499        {
500            goto NextTable;
501        }
502
503        Status = AcpiTbInstallStandardTable (Address,
504            ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL, NULL, FALSE, TRUE,
505            &TableIndex);
506
507        if (ACPI_SUCCESS (Status) &&
508            ACPI_COMPARE_NAMESEG (
509                &AcpiGbl_RootTableList.Tables[TableIndex].Signature,
510                ACPI_SIG_FADT))
511        {
512            AcpiGbl_FadtIndex = TableIndex;
513            AcpiTbParseFadt ();
514        }
515
516NextTable:
517
518        TableEntry += TableEntrySize;
519    }
520
521    AcpiOsUnmapMemory (Table, Length);
522    return_ACPI_STATUS (AE_OK);
523}
524
525
526/*******************************************************************************
527 *
528 * FUNCTION:    AcpiTbGetTable
529 *
530 * PARAMETERS:  TableDesc           - Table descriptor
531 *              OutTable            - Where the pointer to the table is returned
532 *
533 * RETURN:      Status and pointer to the requested table
534 *
535 * DESCRIPTION: Increase a reference to a table descriptor and return the
536 *              validated table pointer.
537 *              If the table descriptor is an entry of the root table list,
538 *              this API must be invoked with ACPI_MTX_TABLES acquired.
539 *
540 ******************************************************************************/
541
542ACPI_STATUS
543AcpiTbGetTable (
544    ACPI_TABLE_DESC        *TableDesc,
545    ACPI_TABLE_HEADER      **OutTable)
546{
547    ACPI_STATUS            Status;
548
549
550    ACPI_FUNCTION_TRACE (AcpiTbGetTable);
551
552
553    if (TableDesc->ValidationCount == 0)
554    {
555        /* Table need to be "VALIDATED" */
556
557        Status = AcpiTbValidateTable (TableDesc);
558        if (ACPI_FAILURE (Status))
559        {
560            return_ACPI_STATUS (Status);
561        }
562    }
563
564    if (TableDesc->ValidationCount < ACPI_MAX_TABLE_VALIDATIONS)
565    {
566        TableDesc->ValidationCount++;
567
568        /*
569         * Detect ValidationCount overflows to ensure that the warning
570         * message will only be printed once.
571         */
572        if (TableDesc->ValidationCount >= ACPI_MAX_TABLE_VALIDATIONS)
573        {
574            ACPI_WARNING((AE_INFO,
575                "Table %p, Validation count overflows\n", TableDesc));
576        }
577    }
578
579    *OutTable = TableDesc->Pointer;
580    return_ACPI_STATUS (AE_OK);
581}
582
583
584/*******************************************************************************
585 *
586 * FUNCTION:    AcpiTbPutTable
587 *
588 * PARAMETERS:  TableDesc           - Table descriptor
589 *
590 * RETURN:      None
591 *
592 * DESCRIPTION: Decrease a reference to a table descriptor and release the
593 *              validated table pointer if no references.
594 *              If the table descriptor is an entry of the root table list,
595 *              this API must be invoked with ACPI_MTX_TABLES acquired.
596 *
597 ******************************************************************************/
598
599void
600AcpiTbPutTable (
601    ACPI_TABLE_DESC        *TableDesc)
602{
603
604    ACPI_FUNCTION_TRACE (AcpiTbPutTable);
605
606
607    if (TableDesc->ValidationCount < ACPI_MAX_TABLE_VALIDATIONS)
608    {
609        TableDesc->ValidationCount--;
610
611        /*
612         * Detect ValidationCount underflows to ensure that the warning
613         * message will only be printed once.
614         */
615        if (TableDesc->ValidationCount >= ACPI_MAX_TABLE_VALIDATIONS)
616        {
617            ACPI_WARNING ((AE_INFO,
618                "Table %p, Validation count underflows\n", TableDesc));
619            return_VOID;
620        }
621    }
622
623    if (TableDesc->ValidationCount == 0)
624    {
625        /* Table need to be "INVALIDATED" */
626
627        AcpiTbInvalidateTable (TableDesc);
628    }
629
630    return_VOID;
631}
632