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 - 2012, 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#define __TBXFROOT_C__
117
118#include "acpi.h"
119#include "accommon.h"
120#include "actables.h"
121
122
123#define _COMPONENT          ACPI_TABLES
124        ACPI_MODULE_NAME    ("tbxfroot")
125
126/* Local prototypes */
127
128static UINT8 *
129AcpiTbScanMemoryForRsdp (
130    UINT8                   *StartAddress,
131    UINT32                  Length);
132
133static ACPI_STATUS
134AcpiTbValidateRsdp (
135    ACPI_TABLE_RSDP         *Rsdp);
136
137
138/*******************************************************************************
139 *
140 * FUNCTION:    AcpiTbValidateRsdp
141 *
142 * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
143 *
144 * RETURN:      Status
145 *
146 * DESCRIPTION: Validate the RSDP (ptr)
147 *
148 ******************************************************************************/
149
150static ACPI_STATUS
151AcpiTbValidateRsdp (
152    ACPI_TABLE_RSDP         *Rsdp)
153{
154
155    /*
156     * The signature and checksum must both be correct
157     *
158     * Note: Sometimes there exists more than one RSDP in memory; the valid
159     * RSDP has a valid checksum, all others have an invalid checksum.
160     */
161    if (ACPI_STRNCMP ((char *) Rsdp, ACPI_SIG_RSDP,
162            sizeof (ACPI_SIG_RSDP)-1) != 0)
163    {
164        /* Nope, BAD Signature */
165
166        return (AE_BAD_SIGNATURE);
167    }
168
169    /* Check the standard checksum */
170
171    if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
172    {
173        return (AE_BAD_CHECKSUM);
174    }
175
176    /* Check extended checksum if table version >= 2 */
177
178    if ((Rsdp->Revision >= 2) &&
179        (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
180    {
181        return (AE_BAD_CHECKSUM);
182    }
183
184    return (AE_OK);
185}
186
187
188/*******************************************************************************
189 *
190 * FUNCTION:    AcpiFindRootPointer
191 *
192 * PARAMETERS:  TableAddress            - Where the table pointer is returned
193 *
194 * RETURN:      Status, RSDP physical address
195 *
196 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
197 *              pointer structure. If it is found, set *RSDP to point to it.
198 *
199 * NOTE1:       The RSDP must be either in the first 1K of the Extended
200 *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
201 *              Only a 32-bit physical address is necessary.
202 *
203 * NOTE2:       This function is always available, regardless of the
204 *              initialization state of the rest of ACPI.
205 *
206 ******************************************************************************/
207
208ACPI_STATUS
209AcpiFindRootPointer (
210    ACPI_SIZE               *TableAddress)
211{
212    UINT8                   *TablePtr;
213    UINT8                   *MemRover;
214    UINT32                  PhysicalAddress;
215
216
217    ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
218
219
220    /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
221
222    TablePtr = AcpiOsMapMemory (
223                (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
224                ACPI_EBDA_PTR_LENGTH);
225    if (!TablePtr)
226    {
227        ACPI_ERROR ((AE_INFO,
228            "Could not map memory at 0x%8.8X for length %u",
229            ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
230
231        return_ACPI_STATUS (AE_NO_MEMORY);
232    }
233
234    ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
235
236    /* Convert segment part to physical address */
237
238    PhysicalAddress <<= 4;
239    AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
240
241    /* EBDA present? */
242
243    if (PhysicalAddress > 0x400)
244    {
245        /*
246         * 1b) Search EBDA paragraphs (EBDA is required to be a
247         *     minimum of 1K length)
248         */
249        TablePtr = AcpiOsMapMemory (
250                    (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
251                    ACPI_EBDA_WINDOW_SIZE);
252        if (!TablePtr)
253        {
254            ACPI_ERROR ((AE_INFO,
255                "Could not map memory at 0x%8.8X for length %u",
256                PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
257
258            return_ACPI_STATUS (AE_NO_MEMORY);
259        }
260
261        MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
262        AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
263
264        if (MemRover)
265        {
266            /* Return the physical address */
267
268            PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
269
270            *TableAddress = PhysicalAddress;
271            return_ACPI_STATUS (AE_OK);
272        }
273    }
274
275    /*
276     * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
277     */
278    TablePtr = AcpiOsMapMemory (
279                (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
280                ACPI_HI_RSDP_WINDOW_SIZE);
281
282    if (!TablePtr)
283    {
284        ACPI_ERROR ((AE_INFO,
285            "Could not map memory at 0x%8.8X for length %u",
286            ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
287
288        return_ACPI_STATUS (AE_NO_MEMORY);
289    }
290
291    MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
292    AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
293
294    if (MemRover)
295    {
296        /* Return the physical address */
297
298        PhysicalAddress = (UINT32)
299            (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
300
301        *TableAddress = PhysicalAddress;
302        return_ACPI_STATUS (AE_OK);
303    }
304
305    /* A valid RSDP was not found */
306
307    ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
308    return_ACPI_STATUS (AE_NOT_FOUND);
309}
310
311ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
312
313
314/*******************************************************************************
315 *
316 * FUNCTION:    AcpiTbScanMemoryForRsdp
317 *
318 * PARAMETERS:  StartAddress        - Starting pointer for search
319 *              Length              - Maximum length to search
320 *
321 * RETURN:      Pointer to the RSDP if found, otherwise NULL.
322 *
323 * DESCRIPTION: Search a block of memory for the RSDP signature
324 *
325 ******************************************************************************/
326
327static UINT8 *
328AcpiTbScanMemoryForRsdp (
329    UINT8                   *StartAddress,
330    UINT32                  Length)
331{
332    ACPI_STATUS             Status;
333    UINT8                   *MemRover;
334    UINT8                   *EndAddress;
335
336
337    ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
338
339
340    EndAddress = StartAddress + Length;
341
342    /* Search from given start address for the requested length */
343
344    for (MemRover = StartAddress; MemRover < EndAddress;
345         MemRover += ACPI_RSDP_SCAN_STEP)
346    {
347        /* The RSDP signature and checksum must both be correct */
348
349        Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
350        if (ACPI_SUCCESS (Status))
351        {
352            /* Sig and checksum valid, we have found a real RSDP */
353
354            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
355                "RSDP located at physical address %p\n", MemRover));
356            return_PTR (MemRover);
357        }
358
359        /* No sig match or bad checksum, keep searching */
360    }
361
362    /* Searched entire block, no RSDP was found */
363
364    ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
365        "Searched entire block from %p, valid RSDP was not found\n",
366        StartAddress));
367    return_PTR (NULL);
368}
369