1/******************************************************************************
2 *
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
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
157#define _COMPONENT          ACPI_TABLES
158        ACPI_MODULE_NAME    ("tbxfroot")
159
160
161/*******************************************************************************
162 *
163 * FUNCTION:    AcpiTbGetRsdpLength
164 *
165 * PARAMETERS:  Rsdp                - Pointer to RSDP
166 *
167 * RETURN:      Table length
168 *
169 * DESCRIPTION: Get the length of the RSDP
170 *
171 ******************************************************************************/
172
173UINT32
174AcpiTbGetRsdpLength (
175    ACPI_TABLE_RSDP         *Rsdp)
176{
177
178    if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
179    {
180        /* BAD Signature */
181
182        return (0);
183    }
184
185    /* "Length" field is available if table version >= 2 */
186
187    if (Rsdp->Revision >= 2)
188    {
189        return (Rsdp->Length);
190    }
191    else
192    {
193        return (ACPI_RSDP_CHECKSUM_LENGTH);
194    }
195}
196
197
198/*******************************************************************************
199 *
200 * FUNCTION:    AcpiTbValidateRsdp
201 *
202 * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
203 *
204 * RETURN:      Status
205 *
206 * DESCRIPTION: Validate the RSDP (ptr)
207 *
208 ******************************************************************************/
209
210ACPI_STATUS
211AcpiTbValidateRsdp (
212    ACPI_TABLE_RSDP         *Rsdp)
213{
214
215    /*
216     * The signature and checksum must both be correct
217     *
218     * Note: Sometimes there exists more than one RSDP in memory; the valid
219     * RSDP has a valid checksum, all others have an invalid checksum.
220     */
221    if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
222    {
223        /* Nope, BAD Signature */
224
225        return (AE_BAD_SIGNATURE);
226    }
227
228    /* Check the standard checksum */
229
230    if (AcpiUtChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
231    {
232        return (AE_BAD_CHECKSUM);
233    }
234
235    /* Check extended checksum if table version >= 2 */
236
237    if ((Rsdp->Revision >= 2) &&
238        (AcpiUtChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
239    {
240        return (AE_BAD_CHECKSUM);
241    }
242
243    return (AE_OK);
244}
245
246
247/*******************************************************************************
248 *
249 * FUNCTION:    AcpiFindRootPointer
250 *
251 * PARAMETERS:  TableAddress            - Where the table pointer is returned
252 *
253 * RETURN:      Status, RSDP physical address
254 *
255 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
256 *              pointer structure. If it is found, set *RSDP to point to it.
257 *
258 * NOTE1:       The RSDP must be either in the first 1K of the Extended
259 *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
260 *              Only a 32-bit physical address is necessary.
261 *
262 * NOTE2:       This function is always available, regardless of the
263 *              initialization state of the rest of ACPI.
264 *
265 ******************************************************************************/
266
267ACPI_STATUS ACPI_INIT_FUNCTION
268AcpiFindRootPointer (
269    ACPI_PHYSICAL_ADDRESS   *TableAddress)
270{
271    UINT8                   *TablePtr;
272    UINT8                   *MemRover;
273    UINT32                  PhysicalAddress;
274    UINT32                  EbdaWindowSize;
275
276
277    ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
278
279
280    /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
281
282    TablePtr = AcpiOsMapMemory (
283        (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
284        ACPI_EBDA_PTR_LENGTH);
285    if (!TablePtr)
286    {
287        ACPI_ERROR ((AE_INFO,
288            "Could not map memory at 0x%8.8X for length %u",
289            ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
290
291        return_ACPI_STATUS (AE_NO_MEMORY);
292    }
293
294    ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
295
296    /* Convert segment part to physical address */
297
298    PhysicalAddress <<= 4;
299    AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
300
301    /* EBDA present? */
302
303    /*
304     * Check that the EBDA pointer from memory is sane and does not point
305     * above valid low memory
306     */
307    if (PhysicalAddress > 0x400 &&
308        PhysicalAddress < 0xA0000)
309    {
310        /*
311         * Calculate the scan window size
312         * The EBDA is not guaranteed to be larger than a KiB and in case
313         * that it is smaller, the scanning function would leave the low
314         * memory and continue to the VGA range.
315         */
316        EbdaWindowSize = ACPI_MIN(ACPI_EBDA_WINDOW_SIZE,
317            0xA0000 - PhysicalAddress);
318
319        /*
320         * 1b) Search EBDA paragraphs
321         */
322        TablePtr = AcpiOsMapMemory (
323            (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
324            EbdaWindowSize);
325        if (!TablePtr)
326        {
327            ACPI_ERROR ((AE_INFO,
328                "Could not map memory at 0x%8.8X for length %u",
329                PhysicalAddress, EbdaWindowSize));
330
331            return_ACPI_STATUS (AE_NO_MEMORY);
332        }
333
334        MemRover = AcpiTbScanMemoryForRsdp (
335            TablePtr, EbdaWindowSize);
336        AcpiOsUnmapMemory (TablePtr, EbdaWindowSize);
337
338        if (MemRover)
339        {
340            /* Return the physical address */
341
342            PhysicalAddress +=
343                (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
344
345            *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
346            return_ACPI_STATUS (AE_OK);
347        }
348    }
349
350    /*
351     * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
352     */
353    TablePtr = AcpiOsMapMemory (
354        (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
355        ACPI_HI_RSDP_WINDOW_SIZE);
356
357    if (!TablePtr)
358    {
359        ACPI_ERROR ((AE_INFO,
360            "Could not map memory at 0x%8.8X for length %u",
361            ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
362
363        return_ACPI_STATUS (AE_NO_MEMORY);
364    }
365
366    MemRover = AcpiTbScanMemoryForRsdp (
367        TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
368    AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
369
370    if (MemRover)
371    {
372        /* Return the physical address */
373
374        PhysicalAddress = (UINT32)
375            (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
376
377        *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
378        return_ACPI_STATUS (AE_OK);
379    }
380
381    /* A valid RSDP was not found */
382
383    ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
384    return_ACPI_STATUS (AE_NOT_FOUND);
385}
386
387ACPI_EXPORT_SYMBOL_INIT (AcpiFindRootPointer)
388
389
390/*******************************************************************************
391 *
392 * FUNCTION:    AcpiTbScanMemoryForRsdp
393 *
394 * PARAMETERS:  StartAddress        - Starting pointer for search
395 *              Length              - Maximum length to search
396 *
397 * RETURN:      Pointer to the RSDP if found, otherwise NULL.
398 *
399 * DESCRIPTION: Search a block of memory for the RSDP signature
400 *
401 ******************************************************************************/
402
403UINT8 *
404AcpiTbScanMemoryForRsdp (
405    UINT8                   *StartAddress,
406    UINT32                  Length)
407{
408    ACPI_STATUS             Status;
409    UINT8                   *MemRover;
410    UINT8                   *EndAddress;
411
412
413    ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
414
415
416    EndAddress = StartAddress + Length;
417
418    /* Search from given start address for the requested length */
419
420    for (MemRover = StartAddress; MemRover < EndAddress;
421         MemRover += ACPI_RSDP_SCAN_STEP)
422    {
423        /* The RSDP signature and checksum must both be correct */
424
425        Status = AcpiTbValidateRsdp (
426            ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
427        if (ACPI_SUCCESS (Status))
428        {
429            /* Sig and checksum valid, we have found a real RSDP */
430
431            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
432                "RSDP located at physical address %p\n", MemRover));
433            return_PTR (MemRover);
434        }
435
436        /* No sig match or bad checksum, keep searching */
437    }
438
439    /* Searched entire block, no RSDP was found */
440
441    ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
442        "Searched entire block from %p, valid RSDP was not found\n",
443        StartAddress));
444    return_PTR (NULL);
445}
446