1 /****************************************************************************** 2 * 3 * Module Name: tbxfroot - Find the root ACPI table (RSDT) 4 * $Revision: 1.106 $ 5 * 6 *****************************************************************************/ 7 8 /****************************************************************************** 9 * 10 * 1. Copyright Notice 11 * 12 * Some or all of this work - Copyright (c) 1999 - 2008, Intel Corp. 13 * All rights reserved. 14 * 15 * 2. License 16 * 17 * 2.1. This is your license from Intel Corp. under its intellectual property 18 * rights. You may have additional license terms from the party that provided 19 * you this software, covering your right to use that party's intellectual 20 * property rights. 21 * 22 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a 23 * copy of the source code appearing in this file ("Covered Code") an 24 * irrevocable, perpetual, worldwide license under Intel's copyrights in the 25 * base code distributed originally by Intel ("Original Intel Code") to copy, 26 * make derivatives, distribute, use and display any portion of the Covered 27 * Code in any form, with the right to sublicense such rights; and 28 * 29 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent 30 * license (with the right to sublicense), under only those claims of Intel 31 * patents that are infringed by the Original Intel Code, to make, use, sell, 32 * offer to sell, and import the Covered Code and derivative works thereof 33 * solely to the minimum extent necessary to exercise the above copyright 34 * license, and in no event shall the patent license extend to any additions 35 * to or modifications of the Original Intel Code. No other license or right 36 * is granted directly or by implication, estoppel or otherwise; 37 * 38 * The above copyright and patent license is granted only if the following 39 * conditions are met: 40 * 41 * 3. Conditions 42 * 43 * 3.1. Redistribution of Source with Rights to Further Distribute Source. 44 * Redistribution of source code of any substantial portion of the Covered 45 * Code or modification with rights to further distribute source must include 46 * the above Copyright Notice, the above License, this list of Conditions, 47 * and the following Disclaimer and Export Compliance provision. In addition, 48 * Licensee must cause all Covered Code to which Licensee contributes to 49 * contain a file documenting the changes Licensee made to create that Covered 50 * Code and the date of any change. Licensee must include in that file the 51 * documentation of any changes made by any predecessor Licensee. Licensee 52 * must include a prominent statement that the modification is derived, 53 * directly or indirectly, from Original Intel Code. 54 * 55 * 3.2. Redistribution of Source with no Rights to Further Distribute Source. 56 * Redistribution of source code of any substantial portion of the Covered 57 * Code or modification without rights to further distribute source must 58 * include the following Disclaimer and Export Compliance provision in the 59 * documentation and/or other materials provided with distribution. In 60 * addition, Licensee may not authorize further sublicense of source of any 61 * portion of the Covered Code, and must include terms to the effect that the 62 * license from Licensee to its licensee is limited to the intellectual 63 * property embodied in the software Licensee provides to its licensee, and 64 * not to intellectual property embodied in modifications its licensee may 65 * make. 66 * 67 * 3.3. Redistribution of Executable. Redistribution in executable form of any 68 * substantial portion of the Covered Code or modification must reproduce the 69 * above Copyright Notice, and the following Disclaimer and Export Compliance 70 * provision in the documentation and/or other materials provided with the 71 * distribution. 72 * 73 * 3.4. Intel retains all right, title, and interest in and to the Original 74 * Intel Code. 75 * 76 * 3.5. Neither the name Intel nor any other trademark owned or controlled by 77 * Intel shall be used in advertising or otherwise to promote the sale, use or 78 * other dealings in products derived from or relating to the Covered Code 79 * without prior written authorization from Intel. 80 * 81 * 4. Disclaimer and Export Compliance 82 * 83 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED 84 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE 85 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE, 86 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY 87 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY 88 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A 89 * PARTICULAR PURPOSE. 90 * 91 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES 92 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR 93 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT, 94 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY 95 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL 96 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS 97 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY 98 * LIMITED REMEDY. 99 * 100 * 4.3. Licensee shall not export, either directly or indirectly, any of this 101 * software or system incorporating such software without first obtaining any 102 * required license or other approval from the U. S. Department of Commerce or 103 * any other agency or department of the United States Government. In the 104 * event Licensee exports any such software from the United States or 105 * re-exports any such software from a foreign destination, Licensee shall 106 * ensure that the distribution and export/re-export of the software is in 107 * compliance with all laws, regulations, orders, or other restrictions of the 108 * U.S. Export Administration Regulations. Licensee agrees that neither it nor 109 * any of its subsidiaries will export/re-export any technical data, process, 110 * software, or service, directly or indirectly, to any country for which the 111 * United States government or any agency thereof requires an export license, 112 * other governmental approval, or letter of assurance, without first obtaining 113 * such license, approval or letter. 114 * 115 *****************************************************************************/ 116 117 #define __TBXFROOT_C__ 118 119 #include "acpi.h" 120 #include "actables.h" 121 122 123 #define _COMPONENT ACPI_TABLES 124 ACPI_MODULE_NAME ("tbxfroot") 125 126 /* Local prototypes */ 127 128 static UINT8 * 129 AcpiTbScanMemoryForRsdp ( 130 UINT8 *StartAddress, 131 UINT32 Length); 132 133 static ACPI_STATUS 134 AcpiTbValidateRsdp ( 135 ACPI_TABLE_RSDP *Rsdp); 136 137 138 /******************************************************************************* 139 * 140 * FUNCTION: AcpiTbValidateRsdp 141 * 142 * PARAMETERS: Rsdp - Pointer to unvalidated RSDP 143 * 144 * RETURN: Status 145 * 146 * DESCRIPTION: Validate the RSDP (ptr) 147 * 148 ******************************************************************************/ 149 150 static ACPI_STATUS 151 AcpiTbValidateRsdp ( 152 ACPI_TABLE_RSDP *Rsdp) 153 { 154 ACPI_FUNCTION_ENTRY (); 155 156 157 /* 158 * The signature and checksum must both be correct 159 * 160 * Note: Sometimes there exists more than one RSDP in memory; the valid 161 * RSDP has a valid checksum, all others have an invalid checksum. 162 */ 163 if (ACPI_STRNCMP ((char *) Rsdp, ACPI_SIG_RSDP, sizeof (ACPI_SIG_RSDP)-1) != 0) 164 { 165 /* Nope, BAD Signature */ 166 167 return (AE_BAD_SIGNATURE); 168 } 169 170 /* Check the standard checksum */ 171 172 if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) 173 { 174 return (AE_BAD_CHECKSUM); 175 } 176 177 /* Check extended checksum if table version >= 2 */ 178 179 if ((Rsdp->Revision >= 2) && 180 (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) 181 { 182 return (AE_BAD_CHECKSUM); 183 } 184 185 return (AE_OK); 186 } 187 188 189 /******************************************************************************* 190 * 191 * FUNCTION: AcpiTbFindRsdp 192 * 193 * PARAMETERS: TableAddress - Where the table pointer is returned 194 * 195 * RETURN: Status, RSDP physical address 196 * 197 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor 198 * pointer structure. If it is found, set *RSDP to point to it. 199 * 200 * NOTE1: The RSDP must be either in the first 1K of the Extended 201 * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.) 202 * Only a 32-bit physical address is necessary. 203 * 204 * NOTE2: This function is always available, regardless of the 205 * initialization state of the rest of ACPI. 206 * 207 ******************************************************************************/ 208 209 ACPI_STATUS 210 AcpiFindRootPointer ( 211 ACPI_SIZE *TableAddress) 212 { 213 UINT8 *TablePtr; 214 UINT8 *MemRover; 215 UINT32 PhysicalAddress; 216 217 218 ACPI_FUNCTION_TRACE (AcpiFindRootPointer); 219 220 221 /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */ 222 223 TablePtr = AcpiOsMapMemory ( 224 (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION, 225 ACPI_EBDA_PTR_LENGTH); 226 if (!TablePtr) 227 { 228 ACPI_ERROR ((AE_INFO, 229 "Could not map memory at %8.8X for length %X", 230 ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH)); 231 232 return_ACPI_STATUS (AE_NO_MEMORY); 233 } 234 235 ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr); 236 237 /* Convert segment part to physical address */ 238 239 PhysicalAddress <<= 4; 240 AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH); 241 242 /* EBDA present? */ 243 244 if (PhysicalAddress > 0x400) 245 { 246 /* 247 * 1b) Search EBDA paragraphs (EBDA is required to be a 248 * minimum of 1K length) 249 */ 250 TablePtr = AcpiOsMapMemory ( 251 (ACPI_PHYSICAL_ADDRESS) PhysicalAddress, 252 ACPI_EBDA_WINDOW_SIZE); 253 if (!TablePtr) 254 { 255 ACPI_ERROR ((AE_INFO, 256 "Could not map memory at %8.8X for length %X", 257 PhysicalAddress, ACPI_EBDA_WINDOW_SIZE)); 258 259 return_ACPI_STATUS (AE_NO_MEMORY); 260 } 261 262 MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE); 263 AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE); 264 265 if (MemRover) 266 { 267 /* Return the physical address */ 268 269 PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr); 270 271 *TableAddress = PhysicalAddress; 272 return_ACPI_STATUS (AE_OK); 273 } 274 } 275 276 /* 277 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh 278 */ 279 TablePtr = AcpiOsMapMemory ( 280 (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE, 281 ACPI_HI_RSDP_WINDOW_SIZE); 282 283 if (!TablePtr) 284 { 285 ACPI_ERROR ((AE_INFO, 286 "Could not map memory at %8.8X for length %X", 287 ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE)); 288 289 return_ACPI_STATUS (AE_NO_MEMORY); 290 } 291 292 MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE); 293 AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE); 294 295 if (MemRover) 296 { 297 /* Return the physical address */ 298 299 PhysicalAddress = (UINT32) 300 (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr)); 301 302 *TableAddress = PhysicalAddress; 303 return_ACPI_STATUS (AE_OK); 304 } 305 306 /* A valid RSDP was not found */ 307 308 ACPI_ERROR ((AE_INFO, "A valid RSDP was not found")); 309 return_ACPI_STATUS (AE_NOT_FOUND); 310 } 311 312 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer) 313 314 315 /******************************************************************************* 316 * 317 * FUNCTION: AcpiTbScanMemoryForRsdp 318 * 319 * PARAMETERS: StartAddress - Starting pointer for search 320 * Length - Maximum length to search 321 * 322 * RETURN: Pointer to the RSDP if found, otherwise NULL. 323 * 324 * DESCRIPTION: Search a block of memory for the RSDP signature 325 * 326 ******************************************************************************/ 327 328 static UINT8 * 329 AcpiTbScanMemoryForRsdp ( 330 UINT8 *StartAddress, 331 UINT32 Length) 332 { 333 ACPI_STATUS Status; 334 UINT8 *MemRover; 335 UINT8 *EndAddress; 336 337 338 ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp); 339 340 341 EndAddress = StartAddress + Length; 342 343 /* Search from given start address for the requested length */ 344 345 for (MemRover = StartAddress; MemRover < EndAddress; 346 MemRover += ACPI_RSDP_SCAN_STEP) 347 { 348 /* The RSDP signature and checksum must both be correct */ 349 350 Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover)); 351 if (ACPI_SUCCESS (Status)) 352 { 353 /* Sig and checksum valid, we have found a real RSDP */ 354 355 ACPI_DEBUG_PRINT ((ACPI_DB_INFO, 356 "RSDP located at physical address %p\n", MemRover)); 357 return_PTR (MemRover); 358 } 359 360 /* No sig match or bad checksum, keep searching */ 361 } 362 363 /* Searched entire block, no RSDP was found */ 364 365 ACPI_DEBUG_PRINT ((ACPI_DB_INFO, 366 "Searched entire block from %p, valid RSDP was not found\n", 367 StartAddress)); 368 return_PTR (NULL); 369 } 370 371