| 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 | |