1 /******************************************************************************
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
5 *****************************************************************************/
7 /******************************************************************************
11 * Some or all of this work - Copyright (c) 1999 - 2014, Intel Corp.
12 * All rights reserved.
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
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
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;
37 * The above copyright and patent license is granted only if the following
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.
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
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
72 * 3.4. Intel retains all right, title, and interest in and to the Original
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.
80 * 4. Disclaimer and Export Compliance
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
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
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.
114 *****************************************************************************/
116 #define __TBXFROOT_C__
119 #include "accommon.h"
120 #include "actables.h"
123 #define _COMPONENT ACPI_TABLES
124 ACPI_MODULE_NAME ("tbxfroot")
127 /*******************************************************************************
129 * FUNCTION: AcpiTbValidateRsdp
131 * PARAMETERS: Rsdp - Pointer to unvalidated RSDP
135 * DESCRIPTION: Validate the RSDP (ptr)
137 ******************************************************************************/
141 ACPI_TABLE_RSDP
*Rsdp
)
145 * The signature and checksum must both be correct
147 * Note: Sometimes there exists more than one RSDP in memory; the valid
148 * RSDP has a valid checksum, all others have an invalid checksum.
150 if (!ACPI_VALIDATE_RSDP_SIG (Rsdp
->Signature
))
152 /* Nope, BAD Signature */
154 return (AE_BAD_SIGNATURE
);
157 /* Check the standard checksum */
159 if (AcpiTbChecksum ((UINT8
*) Rsdp
, ACPI_RSDP_CHECKSUM_LENGTH
) != 0)
161 return (AE_BAD_CHECKSUM
);
164 /* Check extended checksum if table version >= 2 */
166 if ((Rsdp
->Revision
>= 2) &&
167 (AcpiTbChecksum ((UINT8
*) Rsdp
, ACPI_RSDP_XCHECKSUM_LENGTH
) != 0))
169 return (AE_BAD_CHECKSUM
);
176 /*******************************************************************************
178 * FUNCTION: AcpiFindRootPointer
180 * PARAMETERS: TableAddress - Where the table pointer is returned
182 * RETURN: Status, RSDP physical address
184 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
185 * pointer structure. If it is found, set *RSDP to point to it.
187 * NOTE1: The RSDP must be either in the first 1K of the Extended
188 * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
189 * Only a 32-bit physical address is necessary.
191 * NOTE2: This function is always available, regardless of the
192 * initialization state of the rest of ACPI.
194 ******************************************************************************/
197 AcpiFindRootPointer (
198 ACPI_SIZE
*TableAddress
)
202 UINT32 PhysicalAddress
;
205 ACPI_FUNCTION_TRACE (AcpiFindRootPointer
);
208 /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
210 TablePtr
= AcpiOsMapMemory (
211 (ACPI_PHYSICAL_ADDRESS
) ACPI_EBDA_PTR_LOCATION
,
212 ACPI_EBDA_PTR_LENGTH
);
215 ACPI_ERROR ((AE_INFO
,
216 "Could not map memory at 0x%8.8X for length %u",
217 ACPI_EBDA_PTR_LOCATION
, ACPI_EBDA_PTR_LENGTH
));
219 return_ACPI_STATUS (AE_NO_MEMORY
);
222 ACPI_MOVE_16_TO_32 (&PhysicalAddress
, TablePtr
);
224 /* Convert segment part to physical address */
226 PhysicalAddress
<<= 4;
227 AcpiOsUnmapMemory (TablePtr
, ACPI_EBDA_PTR_LENGTH
);
231 if (PhysicalAddress
> 0x400)
234 * 1b) Search EBDA paragraphs (EBDA is required to be a
235 * minimum of 1K length)
237 TablePtr
= AcpiOsMapMemory (
238 (ACPI_PHYSICAL_ADDRESS
) PhysicalAddress
,
239 ACPI_EBDA_WINDOW_SIZE
);
242 ACPI_ERROR ((AE_INFO
,
243 "Could not map memory at 0x%8.8X for length %u",
244 PhysicalAddress
, ACPI_EBDA_WINDOW_SIZE
));
246 return_ACPI_STATUS (AE_NO_MEMORY
);
249 MemRover
= AcpiTbScanMemoryForRsdp (TablePtr
, ACPI_EBDA_WINDOW_SIZE
);
250 AcpiOsUnmapMemory (TablePtr
, ACPI_EBDA_WINDOW_SIZE
);
254 /* Return the physical address */
256 PhysicalAddress
+= (UINT32
) ACPI_PTR_DIFF (MemRover
, TablePtr
);
258 *TableAddress
= PhysicalAddress
;
259 return_ACPI_STATUS (AE_OK
);
264 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
266 TablePtr
= AcpiOsMapMemory (
267 (ACPI_PHYSICAL_ADDRESS
) ACPI_HI_RSDP_WINDOW_BASE
,
268 ACPI_HI_RSDP_WINDOW_SIZE
);
272 ACPI_ERROR ((AE_INFO
,
273 "Could not map memory at 0x%8.8X for length %u",
274 ACPI_HI_RSDP_WINDOW_BASE
, ACPI_HI_RSDP_WINDOW_SIZE
));
276 return_ACPI_STATUS (AE_NO_MEMORY
);
279 MemRover
= AcpiTbScanMemoryForRsdp (TablePtr
, ACPI_HI_RSDP_WINDOW_SIZE
);
280 AcpiOsUnmapMemory (TablePtr
, ACPI_HI_RSDP_WINDOW_SIZE
);
284 /* Return the physical address */
286 PhysicalAddress
= (UINT32
)
287 (ACPI_HI_RSDP_WINDOW_BASE
+ ACPI_PTR_DIFF (MemRover
, TablePtr
));
289 *TableAddress
= PhysicalAddress
;
290 return_ACPI_STATUS (AE_OK
);
293 /* A valid RSDP was not found */
295 ACPI_BIOS_ERROR ((AE_INFO
, "A valid RSDP was not found"));
296 return_ACPI_STATUS (AE_NOT_FOUND
);
299 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer
)
302 /*******************************************************************************
304 * FUNCTION: AcpiTbScanMemoryForRsdp
306 * PARAMETERS: StartAddress - Starting pointer for search
307 * Length - Maximum length to search
309 * RETURN: Pointer to the RSDP if found, otherwise NULL.
311 * DESCRIPTION: Search a block of memory for the RSDP signature
313 ******************************************************************************/
316 AcpiTbScanMemoryForRsdp (
325 ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp
);
328 EndAddress
= StartAddress
+ Length
;
330 /* Search from given start address for the requested length */
332 for (MemRover
= StartAddress
; MemRover
< EndAddress
;
333 MemRover
+= ACPI_RSDP_SCAN_STEP
)
335 /* The RSDP signature and checksum must both be correct */
337 Status
= AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP
, MemRover
));
338 if (ACPI_SUCCESS (Status
))
340 /* Sig and checksum valid, we have found a real RSDP */
342 ACPI_DEBUG_PRINT ((ACPI_DB_INFO
,
343 "RSDP located at physical address %p\n", MemRover
));
344 return_PTR (MemRover
);
347 /* No sig match or bad checksum, keep searching */
350 /* Searched entire block, no RSDP was found */
352 ACPI_DEBUG_PRINT ((ACPI_DB_INFO
,
353 "Searched entire block from %p, valid RSDP was not found\n",