1 /****************************************************************************** 2 * 3 * Module Name: tbxfroot - Find the root ACPI table (RSDT) 4 * 5 *****************************************************************************/ 6 7 /****************************************************************************** 8 * 9 * 1. Copyright Notice 10 * 11 * Some or all of this work - Copyright (c) 1999 - 2009, Intel Corp. 12 * All rights reserved. 13 * 14 * 2. License 15 * 16 * 2.1. This is your license from Intel Corp. under its intellectual property 17 * rights. You may have additional license terms from the party that provided 18 * you this software, covering your right to use that party's intellectual 19 * property rights. 20 * 21 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a 22 * copy of the source code appearing in this file ("Covered Code") an 23 * irrevocable, perpetual, worldwide license under Intel's copyrights in the 24 * base code distributed originally by Intel ("Original Intel Code") to copy, 25 * make derivatives, distribute, use and display any portion of the Covered 26 * Code in any form, with the right to sublicense such rights; and 27 * 28 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent 29 * license (with the right to sublicense), under only those claims of Intel 30 * patents that are infringed by the Original Intel Code, to make, use, sell, 31 * offer to sell, and import the Covered Code and derivative works thereof 32 * solely to the minimum extent necessary to exercise the above copyright 33 * license, and in no event shall the patent license extend to any additions 34 * to or modifications of the Original Intel Code. No other license or right 35 * is granted directly or by implication, estoppel or otherwise; 36 * 37 * The above copyright and patent license is granted only if the following 38 * conditions are met: 39 * 40 * 3. Conditions 41 * 42 * 3.1. Redistribution of Source with Rights to Further Distribute Source. 43 * Redistribution of source code of any substantial portion of the Covered 44 * Code or modification with rights to further distribute source must include 45 * the above Copyright Notice, the above License, this list of Conditions, 46 * and the following Disclaimer and Export Compliance provision. In addition, 47 * Licensee must cause all Covered Code to which Licensee contributes to 48 * contain a file documenting the changes Licensee made to create that Covered 49 * Code and the date of any change. Licensee must include in that file the 50 * documentation of any changes made by any predecessor Licensee. Licensee 51 * must include a prominent statement that the modification is derived, 52 * directly or indirectly, from Original Intel Code. 53 * 54 * 3.2. Redistribution of Source with no Rights to Further Distribute Source. 55 * Redistribution of source code of any substantial portion of the Covered 56 * Code or modification without rights to further distribute source must 57 * include the following Disclaimer and Export Compliance provision in the 58 * documentation and/or other materials provided with distribution. In 59 * addition, Licensee may not authorize further sublicense of source of any 60 * portion of the Covered Code, and must include terms to the effect that the 61 * license from Licensee to its licensee is limited to the intellectual 62 * property embodied in the software Licensee provides to its licensee, and 63 * not to intellectual property embodied in modifications its licensee may 64 * make. 65 * 66 * 3.3. Redistribution of Executable. Redistribution in executable form of any 67 * substantial portion of the Covered Code or modification must reproduce the 68 * above Copyright Notice, and the following Disclaimer and Export Compliance 69 * provision in the documentation and/or other materials provided with the 70 * distribution. 71 * 72 * 3.4. Intel retains all right, title, and interest in and to the Original 73 * Intel Code. 74 * 75 * 3.5. Neither the name Intel nor any other trademark owned or controlled by 76 * Intel shall be used in advertising or otherwise to promote the sale, use or 77 * other dealings in products derived from or relating to the Covered Code 78 * without prior written authorization from Intel. 79 * 80 * 4. Disclaimer and Export Compliance 81 * 82 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED 83 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE 84 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE, 85 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY 86 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY 87 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A 88 * PARTICULAR PURPOSE. 89 * 90 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES 91 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR 92 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT, 93 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY 94 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL 95 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS 96 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY 97 * LIMITED REMEDY. 98 * 99 * 4.3. Licensee shall not export, either directly or indirectly, any of this 100 * software or system incorporating such software without first obtaining any 101 * required license or other approval from the U. S. Department of Commerce or 102 * any other agency or department of the United States Government. In the 103 * event Licensee exports any such software from the United States or 104 * re-exports any such software from a foreign destination, Licensee shall 105 * ensure that the distribution and export/re-export of the software is in 106 * compliance with all laws, regulations, orders, or other restrictions of the 107 * U.S. Export Administration Regulations. Licensee agrees that neither it nor 108 * any of its subsidiaries will export/re-export any technical data, process, 109 * software, or service, directly or indirectly, to any country for which the 110 * United States government or any agency thereof requires an export license, 111 * other governmental approval, or letter of assurance, without first obtaining 112 * such license, approval or letter. 113 * 114 *****************************************************************************/ 115 116 #define __TBXFROOT_C__ 117 118 #include "acpi.h" 119 #include "accommon.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, 164 sizeof (ACPI_SIG_RSDP)-1) != 0) 165 { 166 /* Nope, BAD Signature */ 167 168 return (AE_BAD_SIGNATURE); 169 } 170 171 /* Check the standard checksum */ 172 173 if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) 174 { 175 return (AE_BAD_CHECKSUM); 176 } 177 178 /* Check extended checksum if table version >= 2 */ 179 180 if ((Rsdp->Revision >= 2) && 181 (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) 182 { 183 return (AE_BAD_CHECKSUM); 184 } 185 186 return (AE_OK); 187 } 188 189 190 /******************************************************************************* 191 * 192 * FUNCTION: AcpiFindRootPointer 193 * 194 * PARAMETERS: TableAddress - Where the table pointer is returned 195 * 196 * RETURN: Status, RSDP physical address 197 * 198 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor 199 * pointer structure. If it is found, set *RSDP to point to it. 200 * 201 * NOTE1: The RSDP must be either in the first 1K of the Extended 202 * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.) 203 * Only a 32-bit physical address is necessary. 204 * 205 * NOTE2: This function is always available, regardless of the 206 * initialization state of the rest of ACPI. 207 * 208 ******************************************************************************/ 209 210 ACPI_STATUS 211 AcpiFindRootPointer ( 212 ACPI_SIZE *TableAddress) 213 { 214 UINT8 *TablePtr; 215 UINT8 *MemRover; 216 UINT32 PhysicalAddress; 217 218 219 ACPI_FUNCTION_TRACE (AcpiFindRootPointer); 220 221 222 /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */ 223 224 TablePtr = AcpiOsMapMemory ( 225 (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION, 226 ACPI_EBDA_PTR_LENGTH); 227 if (!TablePtr) 228 { 229 ACPI_ERROR ((AE_INFO, 230 "Could not map memory at %8.8X for length %X", 231 ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH)); 232 233 return_ACPI_STATUS (AE_NO_MEMORY); 234 } 235 236 ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr); 237 238 /* Convert segment part to physical address */ 239 240 PhysicalAddress <<= 4; 241 AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH); 242 243 /* EBDA present? */ 244 245 if (PhysicalAddress > 0x400) 246 { 247 /* 248 * 1b) Search EBDA paragraphs (EBDA is required to be a 249 * minimum of 1K length) 250 */ 251 TablePtr = AcpiOsMapMemory ( 252 (ACPI_PHYSICAL_ADDRESS) PhysicalAddress, 253 ACPI_EBDA_WINDOW_SIZE); 254 if (!TablePtr) 255 { 256 ACPI_ERROR ((AE_INFO, 257 "Could not map memory at %8.8X for length %X", 258 PhysicalAddress, ACPI_EBDA_WINDOW_SIZE)); 259 260 return_ACPI_STATUS (AE_NO_MEMORY); 261 } 262 263 MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE); 264 AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE); 265 266 if (MemRover) 267 { 268 /* Return the physical address */ 269 270 PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr); 271 272 *TableAddress = PhysicalAddress; 273 return_ACPI_STATUS (AE_OK); 274 } 275 } 276 277 /* 278 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh 279 */ 280 TablePtr = AcpiOsMapMemory ( 281 (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE, 282 ACPI_HI_RSDP_WINDOW_SIZE); 283 284 if (!TablePtr) 285 { 286 ACPI_ERROR ((AE_INFO, 287 "Could not map memory at %8.8X for length %X", 288 ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE)); 289 290 return_ACPI_STATUS (AE_NO_MEMORY); 291 } 292 293 MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE); 294 AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE); 295 296 if (MemRover) 297 { 298 /* Return the physical address */ 299 300 PhysicalAddress = (UINT32) 301 (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr)); 302 303 *TableAddress = PhysicalAddress; 304 return_ACPI_STATUS (AE_OK); 305 } 306 307 /* A valid RSDP was not found */ 308 309 ACPI_ERROR ((AE_INFO, "A valid RSDP was not found")); 310 return_ACPI_STATUS (AE_NOT_FOUND); 311 } 312 313 ACPI_EXPORT_SYMBOL (AcpiFindRootPointer) 314 315 316 /******************************************************************************* 317 * 318 * FUNCTION: AcpiTbScanMemoryForRsdp 319 * 320 * PARAMETERS: StartAddress - Starting pointer for search 321 * Length - Maximum length to search 322 * 323 * RETURN: Pointer to the RSDP if found, otherwise NULL. 324 * 325 * DESCRIPTION: Search a block of memory for the RSDP signature 326 * 327 ******************************************************************************/ 328 329 static UINT8 * 330 AcpiTbScanMemoryForRsdp ( 331 UINT8 *StartAddress, 332 UINT32 Length) 333 { 334 ACPI_STATUS Status; 335 UINT8 *MemRover; 336 UINT8 *EndAddress; 337 338 339 ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp); 340 341 342 EndAddress = StartAddress + Length; 343 344 /* Search from given start address for the requested length */ 345 346 for (MemRover = StartAddress; MemRover < EndAddress; 347 MemRover += ACPI_RSDP_SCAN_STEP) 348 { 349 /* The RSDP signature and checksum must both be correct */ 350 351 Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover)); 352 if (ACPI_SUCCESS (Status)) 353 { 354 /* Sig and checksum valid, we have found a real RSDP */ 355 356 ACPI_DEBUG_PRINT ((ACPI_DB_INFO, 357 "RSDP located at physical address %p\n", MemRover)); 358 return_PTR (MemRover); 359 } 360 361 /* No sig match or bad checksum, keep searching */ 362 } 363 364 /* Searched entire block, no RSDP was found */ 365 366 ACPI_DEBUG_PRINT ((ACPI_DB_INFO, 367 "Searched entire block from %p, valid RSDP was not found\n", 368 StartAddress)); 369 return_PTR (NULL); 370 } 371 372