1 /******************************************************************************
2 *
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2016, 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 "acpi.h"
45 #include "accommon.h"
46 #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
65 UINT32
AcpiTbGetRsdpLength(ACPI_TABLE_RSDP * Rsdp)66 AcpiTbGetRsdpLength (
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
102 ACPI_STATUS
AcpiTbValidateRsdp(ACPI_TABLE_RSDP * Rsdp)103 AcpiTbValidateRsdp (
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
159 ACPI_STATUS
AcpiFindRootPointer(ACPI_PHYSICAL_ADDRESS * TableAddress)160 AcpiFindRootPointer (
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 (
213 TablePtr, ACPI_EBDA_WINDOW_SIZE);
214 AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
215
216 if (MemRover)
217 {
218 /* Return the physical address */
219
220 PhysicalAddress +=
221 (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
222
223 *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
224 return_ACPI_STATUS (AE_OK);
225 }
226 }
227
228 /*
229 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
230 */
231 TablePtr = AcpiOsMapMemory (
232 (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
233 ACPI_HI_RSDP_WINDOW_SIZE);
234
235 if (!TablePtr)
236 {
237 ACPI_ERROR ((AE_INFO,
238 "Could not map memory at 0x%8.8X for length %u",
239 ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
240
241 return_ACPI_STATUS (AE_NO_MEMORY);
242 }
243
244 MemRover = AcpiTbScanMemoryForRsdp (
245 TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
246 AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
247
248 if (MemRover)
249 {
250 /* Return the physical address */
251
252 PhysicalAddress = (UINT32)
253 (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
254
255 *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress;
256 return_ACPI_STATUS (AE_OK);
257 }
258
259 /* A valid RSDP was not found */
260
261 ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
262 return_ACPI_STATUS (AE_NOT_FOUND);
263 }
264
ACPI_EXPORT_SYMBOL(AcpiFindRootPointer)265 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
266
267
268 /*******************************************************************************
269 *
270 * FUNCTION: AcpiTbScanMemoryForRsdp
271 *
272 * PARAMETERS: StartAddress - Starting pointer for search
273 * Length - Maximum length to search
274 *
275 * RETURN: Pointer to the RSDP if found, otherwise NULL.
276 *
277 * DESCRIPTION: Search a block of memory for the RSDP signature
278 *
279 ******************************************************************************/
280
281 UINT8 *
282 AcpiTbScanMemoryForRsdp (
283 UINT8 *StartAddress,
284 UINT32 Length)
285 {
286 ACPI_STATUS Status;
287 UINT8 *MemRover;
288 UINT8 *EndAddress;
289
290
291 ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
292
293
294 EndAddress = StartAddress + Length;
295
296 /* Search from given start address for the requested length */
297
298 for (MemRover = StartAddress; MemRover < EndAddress;
299 MemRover += ACPI_RSDP_SCAN_STEP)
300 {
301 /* The RSDP signature and checksum must both be correct */
302
303 Status = AcpiTbValidateRsdp (
304 ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
305 if (ACPI_SUCCESS (Status))
306 {
307 /* Sig and checksum valid, we have found a real RSDP */
308
309 ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
310 "RSDP located at physical address %p\n", MemRover));
311 return_PTR (MemRover);
312 }
313
314 /* No sig match or bad checksum, keep searching */
315 }
316
317 /* Searched entire block, no RSDP was found */
318
319 ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
320 "Searched entire block from %p, valid RSDP was not found\n",
321 StartAddress));
322 return_PTR (NULL);
323 }
324