acpica/tables/tbxfroot.c

0001 /******************************************************************************
0002  *
0003  * Module Name: tbxfroot - Find the root ACPI table (RSDT)
0004  *
0005  *****************************************************************************/
0006
0007 /******************************************************************************
0008  *
0009  * 1. Copyright Notice
0010  *
0011  * Some or all of this work - Copyright (c) 1999 - 2024, Intel Corp.
0012  * All rights reserved.
0013  *
0014  * 2. License
0015  *
0016  * 2.1. This is your license from Intel Corp. under its intellectual property
0017  * rights. You may have additional license terms from the party that provided
0018  * you this software, covering your right to use that party's intellectual
0019  * property rights.
0020  *
0021  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
0022  * copy of the source code appearing in this file ("Covered Code") an
0023  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
0024  * base code distributed originally by Intel ("Original Intel Code") to copy,
0025  * make derivatives, distribute, use and display any portion of the Covered
0026  * Code in any form, with the right to sublicense such rights; and
0027  *
0028  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
0029  * license (with the right to sublicense), under only those claims of Intel
0030  * patents that are infringed by the Original Intel Code, to make, use, sell,
0031  * offer to sell, and import the Covered Code and derivative works thereof
0032  * solely to the minimum extent necessary to exercise the above copyright
0033  * license, and in no event shall the patent license extend to any additions
0034  * to or modifications of the Original Intel Code. No other license or right
0035  * is granted directly or by implication, estoppel or otherwise;
0036  *
0037  * The above copyright and patent license is granted only if the following
0038  * conditions are met:
0039  *
0040  * 3. Conditions
0041  *
0042  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
0043  * Redistribution of source code of any substantial portion of the Covered
0044  * Code or modification with rights to further distribute source must include
0045  * the above Copyright Notice, the above License, this list of Conditions,
0046  * and the following Disclaimer and Export Compliance provision. In addition,
0047  * Licensee must cause all Covered Code to which Licensee contributes to
0048  * contain a file documenting the changes Licensee made to create that Covered
0049  * Code and the date of any change. Licensee must include in that file the
0050  * documentation of any changes made by any predecessor Licensee. Licensee
0051  * must include a prominent statement that the modification is derived,
0052  * directly or indirectly, from Original Intel Code.
0053  *
0054  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
0055  * Redistribution of source code of any substantial portion of the Covered
0056  * Code or modification without rights to further distribute source must
0057  * include the following Disclaimer and Export Compliance provision in the
0058  * documentation and/or other materials provided with distribution. In
0059  * addition, Licensee may not authorize further sublicense of source of any
0060  * portion of the Covered Code, and must include terms to the effect that the
0061  * license from Licensee to its licensee is limited to the intellectual
0062  * property embodied in the software Licensee provides to its licensee, and
0063  * not to intellectual property embodied in modifications its licensee may
0064  * make.
0065  *
0066  * 3.3. Redistribution of Executable. Redistribution in executable form of any
0067  * substantial portion of the Covered Code or modification must reproduce the
0068  * above Copyright Notice, and the following Disclaimer and Export Compliance
0069  * provision in the documentation and/or other materials provided with the
0070  * distribution.
0071  *
0072  * 3.4. Intel retains all right, title, and interest in and to the Original
0073  * Intel Code.
0074  *
0075  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
0076  * Intel shall be used in advertising or otherwise to promote the sale, use or
0077  * other dealings in products derived from or relating to the Covered Code
0078  * without prior written authorization from Intel.
0079  *
0080  * 4. Disclaimer and Export Compliance
0081  *
0082  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
0083  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
0084  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
0085  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
0086  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
0087  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
0088  * PARTICULAR PURPOSE.
0089  *
0090  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
0091  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
0092  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
0093  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
0094  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
0095  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
0096  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
0097  * LIMITED REMEDY.
0098  *
0099  * 4.3. Licensee shall not export, either directly or indirectly, any of this
0100  * software or system incorporating such software without first obtaining any
0101  * required license or other approval from the U. S. Department of Commerce or
0102  * any other agency or department of the United States Government. In the
0103  * event Licensee exports any such software from the United States or
0104  * re-exports any such software from a foreign destination, Licensee shall
0105  * ensure that the distribution and export/re-export of the software is in
0106  * compliance with all laws, regulations, orders, or other restrictions of the
0107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
0108  * any of its subsidiaries will export/re-export any technical data, process,
0109  * software, or service, directly or indirectly, to any country for which the
0110  * United States government or any agency thereof requires an export license,
0111  * other governmental approval, or letter of assurance, without first obtaining
0112  * such license, approval or letter.
0113  *
0114  *****************************************************************************
0115  *
0116  * Alternatively, you may choose to be licensed under the terms of the
0117  * following license:
0118  *
0119  * Redistribution and use in source and binary forms, with or without
0120  * modification, are permitted provided that the following conditions
0121  * are met:
0122  * 1. Redistributions of source code must retain the above copyright
0123  *    notice, this list of conditions, and the following disclaimer,
0124  *    without modification.
0125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
0126  *    substantially similar to the "NO WARRANTY" disclaimer below
0127  *    ("Disclaimer") and any redistribution must be conditioned upon
0128  *    including a substantially similar Disclaimer requirement for further
0129  *    binary redistribution.
0130  * 3. Neither the names of the above-listed copyright holders nor the names
0131  *    of any contributors may be used to endorse or promote products derived
0132  *    from this software without specific prior written permission.
0133  *
0134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
0135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
0136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
0137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
0138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
0139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
0140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
0141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
0142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
0143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
0144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
0145  *
0146  * Alternatively, you may choose to be licensed under the terms of the
0147  * GNU General Public License ("GPL") version 2 as published by the Free
0148  * Software Foundation.
0149  *
0150  *****************************************************************************/
0151
0152 #include "acpi.h"
0153 #include "accommon.h"
0154 #include "actables.h"
0155
0156
0157 #define _COMPONENT          ACPI_TABLES
0158         ACPI_MODULE_NAME    ("tbxfroot")
0159
0160
0161 /*******************************************************************************
0162  *
0163  * FUNCTION:    AcpiTbGetRsdpLength
0164  *
0165  * PARAMETERS:  Rsdp                - Pointer to RSDP
0166  *
0167  * RETURN:      Table length
0168  *
0169  * DESCRIPTION: Get the length of the RSDP
0170  *
0171  ******************************************************************************/
0172
0173 UINT32
0174 AcpiTbGetRsdpLength (
0175     ACPI_TABLE_RSDP         *Rsdp)
0176 {
0177
0178     if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
0179     {
0180         /* BAD Signature */
0181
0182         return (0);
0183     }
0184
0185     /* "Length" field is available if table version >= 2 */
0186
0187     if (Rsdp->Revision >= 2)
0188     {
0189         return (Rsdp->Length);
0190     }
0191     else
0192     {
0193         return (ACPI_RSDP_CHECKSUM_LENGTH);
0194     }
0195 }
0196
0197
0198 /*******************************************************************************
0199  *
0200  * FUNCTION:    AcpiTbValidateRsdp
0201  *
0202  * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
0203  *
0204  * RETURN:      Status
0205  *
0206  * DESCRIPTION: Validate the RSDP (ptr)
0207  *
0208  ******************************************************************************/
0209
0210 ACPI_STATUS
0211 AcpiTbValidateRsdp (
0212     ACPI_TABLE_RSDP         *Rsdp)
0213 {
0214
0215     /*
0216      * The signature and checksum must both be correct
0217      *
0218      * Note: Sometimes there exists more than one RSDP in memory; the valid
0219      * RSDP has a valid checksum, all others have an invalid checksum.
0220      */
0221     if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
0222     {
0223         /* Nope, BAD Signature */
0224
0225         return (AE_BAD_SIGNATURE);
0226     }
0227
0228     /* Check the standard checksum */
0229
0230     if (AcpiUtChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
0231     {
0232         return (AE_BAD_CHECKSUM);
0233     }
0234
0235     /* Check extended checksum if table version >= 2 */
0236
0237     if ((Rsdp->Revision >= 2) &&
0238         (AcpiUtChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
0239     {
0240         return (AE_BAD_CHECKSUM);
0241     }
0242
0243     return (AE_OK);
0244 }
0245
0246
0247 /*******************************************************************************
0248  *
0249  * FUNCTION:    AcpiFindRootPointer
0250  *
0251  * PARAMETERS:  TableAddress            - Where the table pointer is returned
0252  *
0253  * RETURN:      Status, RSDP physical address
0254  *
0255  * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
0256  *              pointer structure. If it is found, set *RSDP to point to it.
0257  *
0258  * NOTE1:       The RSDP must be either in the first 1K of the Extended
0259  *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
0260  *              Only a 32-bit physical address is necessary.
0261  *
0262  * NOTE2:       This function is always available, regardless of the
0263  *              initialization state of the rest of ACPI.
0264  *
0265  ******************************************************************************/
0266
0267 ACPI_STATUS ACPI_INIT_FUNCTION
0268 AcpiFindRootPointer (
0269     ACPI_PHYSICAL_ADDRESS   *TableAddress)
0270 {
0271     UINT8                   *TablePtr;
0272     UINT8                   *MemRover;
0273     UINT32                  PhysicalAddress;
0274     UINT32                  EbdaWindowSize;
0275
0276
0277     ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
0278
0279
0280     /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
0281
0282     TablePtr = AcpiOsMapMemory (
0283         (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
0284         ACPI_EBDA_PTR_LENGTH);
0285     if (!TablePtr)
0286     {
0287         ACPI_ERROR ((AE_INFO,
0288             "Could not map memory at 0x%8.8X for length %u",
0289             ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
0290
0291         return_ACPI_STATUS (AE_NO_MEMORY);
0292     }
0293
0294     ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
0295
0296     /* Convert segment part to physical address */
0297
0298     PhysicalAddress <<= 4;
0299     AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
0300
0301     /* EBDA present? */
0302
0303     /*
0304      * Check that the EBDA pointer from memory is sane and does not point
0305      * above valid low memory
0306      */
0307     if (PhysicalAddress > 0x400 &&
0308         PhysicalAddress < 0xA0000)
0309     {
0310         /*
0311          * Calculate the scan window size
0312          * The EBDA is not guaranteed to be larger than a KiB and in case
0313          * that it is smaller, the scanning function would leave the low
0314          * memory and continue to the VGA range.
0315          */
0316         EbdaWindowSize = ACPI_MIN(ACPI_EBDA_WINDOW_SIZE,
0317             0xA0000 - PhysicalAddress);
0318
0319         /*
0320          * 1b) Search EBDA paragraphs
0321          */
0322         TablePtr = AcpiOsMapMemory (
0323             (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
0324             EbdaWindowSize);
0325         if (!TablePtr)
0326         {
0327             ACPI_ERROR ((AE_INFO,
0328                 "Could not map memory at 0x%8.8X for length %u",
0329                 PhysicalAddress, EbdaWindowSize));
0330
0331             return_ACPI_STATUS (AE_NO_MEMORY);
0332         }
0333
0334         MemRover = AcpiTbScanMemoryForRsdp (
0335             TablePtr, EbdaWindowSize);
0336         AcpiOsUnmapMemory (TablePtr, EbdaWindowSize);
0337
0338         if (MemRover)
0339         {
0340             /* Return the physical address */
0341
0342             PhysicalAddress +=
0343                 (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
0344
0345             *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
0346             return_ACPI_STATUS (AE_OK);
0347         }
0348     }
0349
0350     /*
0351      * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
0352      */
0353     TablePtr = AcpiOsMapMemory (
0354         (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
0355         ACPI_HI_RSDP_WINDOW_SIZE);
0356
0357     if (!TablePtr)
0358     {
0359         ACPI_ERROR ((AE_INFO,
0360             "Could not map memory at 0x%8.8X for length %u",
0361             ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
0362
0363         return_ACPI_STATUS (AE_NO_MEMORY);
0364     }
0365
0366     MemRover = AcpiTbScanMemoryForRsdp (
0367         TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
0368     AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
0369
0370     if (MemRover)
0371     {
0372         /* Return the physical address */
0373
0374         PhysicalAddress = (UINT32)
0375             (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
0376
0377         *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
0378         return_ACPI_STATUS (AE_OK);
0379     }
0380
0381     /* A valid RSDP was not found */
0382
0383     ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
0384     return_ACPI_STATUS (AE_NOT_FOUND);
0385 }
0386
0387 ACPI_EXPORT_SYMBOL_INIT (AcpiFindRootPointer)
0388
0389
0390 /*******************************************************************************
0391  *
0392  * FUNCTION:    AcpiTbScanMemoryForRsdp
0393  *
0394  * PARAMETERS:  StartAddress        - Starting pointer for search
0395  *              Length              - Maximum length to search
0396  *
0397  * RETURN:      Pointer to the RSDP if found, otherwise NULL.
0398  *
0399  * DESCRIPTION: Search a block of memory for the RSDP signature
0400  *
0401  ******************************************************************************/
0402
0403 UINT8 *
0404 AcpiTbScanMemoryForRsdp (
0405     UINT8                   *StartAddress,
0406     UINT32                  Length)
0407 {
0408     ACPI_STATUS             Status;
0409     UINT8                   *MemRover;
0410     UINT8                   *EndAddress;
0411
0412
0413     ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
0414
0415
0416     EndAddress = StartAddress + Length;
0417
0418     /* Search from given start address for the requested length */
0419
0420     for (MemRover = StartAddress; MemRover < EndAddress;
0421          MemRover += ACPI_RSDP_SCAN_STEP)
0422     {
0423         /* The RSDP signature and checksum must both be correct */
0424
0425         Status = AcpiTbValidateRsdp (
0426             ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
0427         if (ACPI_SUCCESS (Status))
0428         {
0429             /* Sig and checksum valid, we have found a real RSDP */
0430
0431             ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
0432                 "RSDP located at physical address %p\n", MemRover));
0433             return_PTR (MemRover);
0434         }
0435
0436         /* No sig match or bad checksum, keep searching */
0437     }
0438
0439     /* Searched entire block, no RSDP was found */
0440
0441     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
0442         "Searched entire block from %p, valid RSDP was not found\n",
0443         StartAddress));
0444     return_PTR (NULL);
0445 }