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 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 (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