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 |
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 |
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 ACPI_INIT_FUNCTION |
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 | |
265 | ACPI_EXPORT_SYMBOL_INIT (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 | |