tbxfroot.c revision 281687 
1/******************************************************************************
2 *
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2015, Intel Corp.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions, and the following disclaimer,
16 *    without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 *    substantially similar to the "NO WARRANTY" disclaimer below
19 *    ("Disclaimer") and any redistribution must be conditioned upon
20 *    including a substantially similar Disclaimer requirement for further
21 *    binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 *    of any contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44#include <contrib/dev/acpica/include/acpi.h>
45#include <contrib/dev/acpica/include/accommon.h>
46#include <contrib/dev/acpica/include/actables.h>
47
48
49#define _COMPONENT          ACPI_TABLES
50        ACPI_MODULE_NAME    ("tbxfroot")
51
52
53/*******************************************************************************
54 *
55 * FUNCTION:    AcpiTbGetRsdpLength
56 *
57 * PARAMETERS:  Rsdp                - Pointer to RSDP
58 *
59 * RETURN:      Table length
60 *
61 * DESCRIPTION: Get the length of the RSDP
62 *
63 ******************************************************************************/
64
65UINT32
66AcpiTbGetRsdpLength (
67    ACPI_TABLE_RSDP         *Rsdp)
68{
69
70    if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
71    {
72        /* BAD Signature */
73
74        return (0);
75    }
76
77    /* "Length" field is available if table version >= 2 */
78
79    if (Rsdp->Revision >= 2)
80    {
81        return (Rsdp->Length);
82    }
83    else
84    {
85        return (ACPI_RSDP_CHECKSUM_LENGTH);
86    }
87}
88
89
90/*******************************************************************************
91 *
92 * FUNCTION:    AcpiTbValidateRsdp
93 *
94 * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
95 *
96 * RETURN:      Status
97 *
98 * DESCRIPTION: Validate the RSDP (ptr)
99 *
100 ******************************************************************************/
101
102ACPI_STATUS
103AcpiTbValidateRsdp (
104    ACPI_TABLE_RSDP         *Rsdp)
105{
106
107    /*
108     * The signature and checksum must both be correct
109     *
110     * Note: Sometimes there exists more than one RSDP in memory; the valid
111     * RSDP has a valid checksum, all others have an invalid checksum.
112     */
113    if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
114    {
115        /* Nope, BAD Signature */
116
117        return (AE_BAD_SIGNATURE);
118    }
119
120    /* Check the standard checksum */
121
122    if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
123    {
124        return (AE_BAD_CHECKSUM);
125    }
126
127    /* Check extended checksum if table version >= 2 */
128
129    if ((Rsdp->Revision >= 2) &&
130        (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
131    {
132        return (AE_BAD_CHECKSUM);
133    }
134
135    return (AE_OK);
136}
137
138
139/*******************************************************************************
140 *
141 * FUNCTION:    AcpiFindRootPointer
142 *
143 * PARAMETERS:  TableAddress            - Where the table pointer is returned
144 *
145 * RETURN:      Status, RSDP physical address
146 *
147 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
148 *              pointer structure. If it is found, set *RSDP to point to it.
149 *
150 * NOTE1:       The RSDP must be either in the first 1K of the Extended
151 *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
152 *              Only a 32-bit physical address is necessary.
153 *
154 * NOTE2:       This function is always available, regardless of the
155 *              initialization state of the rest of ACPI.
156 *
157 ******************************************************************************/
158
159ACPI_STATUS
160AcpiFindRootPointer (
161    ACPI_PHYSICAL_ADDRESS   *TableAddress)
162{
163    UINT8                   *TablePtr;
164    UINT8                   *MemRover;
165    UINT32                  PhysicalAddress;
166
167
168    ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
169
170
171    /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
172
173    TablePtr = AcpiOsMapMemory (
174                (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
175                ACPI_EBDA_PTR_LENGTH);
176    if (!TablePtr)
177    {
178        ACPI_ERROR ((AE_INFO,
179            "Could not map memory at 0x%8.8X for length %u",
180            ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
181
182        return_ACPI_STATUS (AE_NO_MEMORY);
183    }
184
185    ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
186
187    /* Convert segment part to physical address */
188
189    PhysicalAddress <<= 4;
190    AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
191
192    /* EBDA present? */
193
194    if (PhysicalAddress > 0x400)
195    {
196        /*
197         * 1b) Search EBDA paragraphs (EBDA is required to be a
198         *     minimum of 1K length)
199         */
200        TablePtr = AcpiOsMapMemory (
201                    (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
202                    ACPI_EBDA_WINDOW_SIZE);
203        if (!TablePtr)
204        {
205            ACPI_ERROR ((AE_INFO,
206                "Could not map memory at 0x%8.8X for length %u",
207                PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
208
209            return_ACPI_STATUS (AE_NO_MEMORY);
210        }
211
212        MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
213        AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
214
215        if (MemRover)
216        {
217            /* Return the physical address */
218
219            PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
220
221            *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
222            return_ACPI_STATUS (AE_OK);
223        }
224    }
225
226    /*
227     * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
228     */
229    TablePtr = AcpiOsMapMemory (
230                (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
231                ACPI_HI_RSDP_WINDOW_SIZE);
232
233    if (!TablePtr)
234    {
235        ACPI_ERROR ((AE_INFO,
236            "Could not map memory at 0x%8.8X for length %u",
237            ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
238
239        return_ACPI_STATUS (AE_NO_MEMORY);
240    }
241
242    MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
243    AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
244
245    if (MemRover)
246    {
247        /* Return the physical address */
248
249        PhysicalAddress = (UINT32)
250            (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
251
252        *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
253        return_ACPI_STATUS (AE_OK);
254    }
255
256    /* A valid RSDP was not found */
257
258    ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
259    return_ACPI_STATUS (AE_NOT_FOUND);
260}
261
262ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
263
264
265/*******************************************************************************
266 *
267 * FUNCTION:    AcpiTbScanMemoryForRsdp
268 *
269 * PARAMETERS:  StartAddress        - Starting pointer for search
270 *              Length              - Maximum length to search
271 *
272 * RETURN:      Pointer to the RSDP if found, otherwise NULL.
273 *
274 * DESCRIPTION: Search a block of memory for the RSDP signature
275 *
276 ******************************************************************************/
277
278UINT8 *
279AcpiTbScanMemoryForRsdp (
280    UINT8                   *StartAddress,
281    UINT32                  Length)
282{
283    ACPI_STATUS             Status;
284    UINT8                   *MemRover;
285    UINT8                   *EndAddress;
286
287
288    ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
289
290
291    EndAddress = StartAddress + Length;
292
293    /* Search from given start address for the requested length */
294
295    for (MemRover = StartAddress; MemRover < EndAddress;
296         MemRover += ACPI_RSDP_SCAN_STEP)
297    {
298        /* The RSDP signature and checksum must both be correct */
299
300        Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
301        if (ACPI_SUCCESS (Status))
302        {
303            /* Sig and checksum valid, we have found a real RSDP */
304
305            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
306                "RSDP located at physical address %p\n", MemRover));
307            return_PTR (MemRover);
308        }
309
310        /* No sig match or bad checksum, keep searching */
311    }
312
313    /* Searched entire block, no RSDP was found */
314
315    ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
316        "Searched entire block from %p, valid RSDP was not found\n",
317        StartAddress));
318    return_PTR (NULL);
319}
320