drivers/acpi/acpica/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils   - table utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2011, 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/acpi.h>
  45 #include "accommon.h"
  46 #include "actables.h"
  47
  48 #define _COMPONENT          ACPI_TABLES
  49 ACPI_MODULE_NAME("tbutils")
  50
  51 /* Local prototypes */
  52 static void acpi_tb_fix_string(char *string, acpi_size length);
  53
  54 static void
  55 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
  56                              struct acpi_table_header *header);
  57
  58 static acpi_physical_address
  59 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size);
  60
  61 /*******************************************************************************
  62  *
  63  * FUNCTION:    acpi_tb_check_xsdt
  64  *
  65  * PARAMETERS:  address                    - Pointer to the XSDT
  66  *
  67  * RETURN:      status
  68  *              AE_OK - XSDT is okay
  69  *              AE_NO_MEMORY - can't map XSDT
  70  *              AE_INVALID_TABLE_LENGTH - invalid table length
  71  *              AE_NULL_ENTRY - XSDT has NULL entry
  72  *
  73  * DESCRIPTION: validate XSDT
  74 ******************************************************************************/
  75
  76 static acpi_status
  77 acpi_tb_check_xsdt(acpi_physical_address address)
  78 {
  79         struct acpi_table_header *table;
  80         u32 length;
  81         u64 xsdt_entry_address;
  82         u8 *table_entry;
  83         u32 table_count;
  84         int i;
  85
  86         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
  87         if (!table)
  88                 return AE_NO_MEMORY;
  89
  90         length = table->length;
  91         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
  92         if (length < sizeof(struct acpi_table_header))
  93                 return AE_INVALID_TABLE_LENGTH;
  94
  95         table = acpi_os_map_memory(address, length);
  96         if (!table)
  97                 return AE_NO_MEMORY;
  98
  99         /* Calculate the number of tables described in XSDT */
 100         table_count =
 101                 (u32) ((table->length -
 102                 sizeof(struct acpi_table_header)) / sizeof(u64));
 103         table_entry =
 104                 ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 105         for (i = 0; i < table_count; i++) {
 106                 ACPI_MOVE_64_TO_64(&xsdt_entry_address, table_entry);
 107                 if (!xsdt_entry_address) {
 108                         /* XSDT has NULL entry */
 109                         break;
 110                 }
 111                 table_entry += sizeof(u64);
 112         }
 113         acpi_os_unmap_memory(table, length);
 114
 115         if (i < table_count)
 116                 return AE_NULL_ENTRY;
 117         else
 118                 return AE_OK;
 119 }
 120
 121 /*******************************************************************************
 122  *
 123  * FUNCTION:    acpi_tb_initialize_facs
 124  *
 125  * PARAMETERS:  None
 126  *
 127  * RETURN:      Status
 128  *
 129  * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
 130  *              for accessing the Global Lock and Firmware Waking Vector
 131  *
 132  ******************************************************************************/
 133
 134 acpi_status acpi_tb_initialize_facs(void)
 135 {
 136         acpi_status status;
 137
 138         status = acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 139                                          ACPI_CAST_INDIRECT_PTR(struct
 140                                                                 acpi_table_header,
 141                                                                 &acpi_gbl_FACS));
 142         return status;
 143 }
 144
 145 /*******************************************************************************
 146  *
 147  * FUNCTION:    acpi_tb_tables_loaded
 148  *
 149  * PARAMETERS:  None
 150  *
 151  * RETURN:      TRUE if required ACPI tables are loaded
 152  *
 153  * DESCRIPTION: Determine if the minimum required ACPI tables are present
 154  *              (FADT, FACS, DSDT)
 155  *
 156  ******************************************************************************/
 157
 158 u8 acpi_tb_tables_loaded(void)
 159 {
 160
 161         if (acpi_gbl_root_table_list.current_table_count >= 3) {
 162                 return (TRUE);
 163         }
 164
 165         return (FALSE);
 166 }
 167
 168 /*******************************************************************************
 169  *
 170  * FUNCTION:    acpi_tb_fix_string
 171  *
 172  * PARAMETERS:  String              - String to be repaired
 173  *              Length              - Maximum length
 174  *
 175  * RETURN:      None
 176  *
 177  * DESCRIPTION: Replace every non-printable or non-ascii byte in the string
 178  *              with a question mark '?'.
 179  *
 180  ******************************************************************************/
 181
 182 static void acpi_tb_fix_string(char *string, acpi_size length)
 183 {
 184
 185         while (length && *string) {
 186                 if (!ACPI_IS_PRINT(*string)) {
 187                         *string = '?';
 188                 }
 189                 string++;
 190                 length--;
 191         }
 192 }
 193
 194 /*******************************************************************************
 195  *
 196  * FUNCTION:    acpi_tb_cleanup_table_header
 197  *
 198  * PARAMETERS:  out_header          - Where the cleaned header is returned
 199  *              Header              - Input ACPI table header
 200  *
 201  * RETURN:      Returns the cleaned header in out_header
 202  *
 203  * DESCRIPTION: Copy the table header and ensure that all "string" fields in
 204  *              the header consist of printable characters.
 205  *
 206  ******************************************************************************/
 207
 208 static void
 209 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
 210                              struct acpi_table_header *header)
 211 {
 212
 213         ACPI_MEMCPY(out_header, header, sizeof(struct acpi_table_header));
 214
 215         acpi_tb_fix_string(out_header->signature, ACPI_NAME_SIZE);
 216         acpi_tb_fix_string(out_header->oem_id, ACPI_OEM_ID_SIZE);
 217         acpi_tb_fix_string(out_header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
 218         acpi_tb_fix_string(out_header->asl_compiler_id, ACPI_NAME_SIZE);
 219 }
 220
 221 /*******************************************************************************
 222  *
 223  * FUNCTION:    acpi_tb_print_table_header
 224  *
 225  * PARAMETERS:  Address             - Table physical address
 226  *              Header              - Table header
 227  *
 228  * RETURN:      None
 229  *
 230  * DESCRIPTION: Print an ACPI table header. Special cases for FACS and RSDP.
 231  *
 232  ******************************************************************************/
 233
 234 void
 235 acpi_tb_print_table_header(acpi_physical_address address,
 236                            struct acpi_table_header *header)
 237 {
 238         struct acpi_table_header local_header;
 239
 240         if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_FACS)) {
 241
 242                 /* FACS only has signature and length fields */
 243
 244                 ACPI_INFO((AE_INFO, "%4.4s 0x%8.8X%8.8X %05X",
 245                            header->signature, ACPI_FORMAT_UINT64(address),
 246                            header->length));
 247         } else if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_RSDP)) {
 248
 249                 /* RSDP has no common fields */
 250
 251                 ACPI_MEMCPY(local_header.oem_id,
 252                             ACPI_CAST_PTR(struct acpi_table_rsdp,
 253                                           header)->oem_id, ACPI_OEM_ID_SIZE);
 254                 acpi_tb_fix_string(local_header.oem_id, ACPI_OEM_ID_SIZE);
 255
 256                 ACPI_INFO((AE_INFO, "RSDP 0x%8.8X%8.8X %05X (v%.2d %6.6s)",
 257                            ACPI_FORMAT_UINT64(address),
 258                            (ACPI_CAST_PTR(struct acpi_table_rsdp, header)->
 259                             revision >
 260                             0) ? ACPI_CAST_PTR(struct acpi_table_rsdp,
 261                                                header)->length : 20,
 262                            ACPI_CAST_PTR(struct acpi_table_rsdp,
 263                                          header)->revision,
 264                            local_header.oem_id));
 265         } else {
 266                 /* Standard ACPI table with full common header */
 267
 268                 acpi_tb_cleanup_table_header(&local_header, header);
 269
 270                 ACPI_INFO((AE_INFO,
 271                            "%-4.4s 0x%8.8X%8.8X %05X (v%.2d %-6.6s %-8.8s %08X %-4.4s %08X)",
 272                            local_header.signature, ACPI_FORMAT_UINT64(address),
 273                            local_header.length, local_header.revision,
 274                            local_header.oem_id, local_header.oem_table_id,
 275                            local_header.oem_revision,
 276                            local_header.asl_compiler_id,
 277                            local_header.asl_compiler_revision));
 278
 279         }
 280 }
 281
 282 /*******************************************************************************
 283  *
 284  * FUNCTION:    acpi_tb_validate_checksum
 285  *
 286  * PARAMETERS:  Table               - ACPI table to verify
 287  *              Length              - Length of entire table
 288  *
 289  * RETURN:      Status
 290  *
 291  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
 292  *              exception on bad checksum.
 293  *
 294  ******************************************************************************/
 295
 296 acpi_status acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length)
 297 {
 298         u8 checksum;
 299
 300         /* Compute the checksum on the table */
 301
 302         checksum = acpi_tb_checksum(ACPI_CAST_PTR(u8, table), length);
 303
 304         /* Checksum ok? (should be zero) */
 305
 306         if (checksum) {
 307                 ACPI_WARNING((AE_INFO,
 308                               "Incorrect checksum in table [%4.4s] - 0x%2.2X, should be 0x%2.2X",
 309                               table->signature, table->checksum,
 310                               (u8) (table->checksum - checksum)));
 311
 312 #if (ACPI_CHECKSUM_ABORT)
 313
 314                 return (AE_BAD_CHECKSUM);
 315 #endif
 316         }
 317
 318         return (AE_OK);
 319 }
 320
 321 /*******************************************************************************
 322  *
 323  * FUNCTION:    acpi_tb_checksum
 324  *
 325  * PARAMETERS:  Buffer          - Pointer to memory region to be checked
 326  *              Length          - Length of this memory region
 327  *
 328  * RETURN:      Checksum (u8)
 329  *
 330  * DESCRIPTION: Calculates circular checksum of memory region.
 331  *
 332  ******************************************************************************/
 333
 334 u8 acpi_tb_checksum(u8 *buffer, u32 length)
 335 {
 336         u8 sum = 0;
 337         u8 *end = buffer + length;
 338
 339         while (buffer < end) {
 340                 sum = (u8) (sum + *(buffer++));
 341         }
 342
 343         return sum;
 344 }
 345
 346 /*******************************************************************************
 347  *
 348  * FUNCTION:    acpi_tb_check_dsdt_header
 349  *
 350  * PARAMETERS:  None
 351  *
 352  * RETURN:      None
 353  *
 354  * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 355  *              if the DSDT has been replaced from outside the OS and/or if
 356  *              the DSDT header has been corrupted.
 357  *
 358  ******************************************************************************/
 359
 360 void acpi_tb_check_dsdt_header(void)
 361 {
 362
 363         /* Compare original length and checksum to current values */
 364
 365         if (acpi_gbl_original_dsdt_header.length != acpi_gbl_DSDT->length ||
 366             acpi_gbl_original_dsdt_header.checksum != acpi_gbl_DSDT->checksum) {
 367                 ACPI_ERROR((AE_INFO,
 368                             "The DSDT has been corrupted or replaced - old, new headers below"));
 369                 acpi_tb_print_table_header(0, &acpi_gbl_original_dsdt_header);
 370                 acpi_tb_print_table_header(0, acpi_gbl_DSDT);
 371
 372                 ACPI_ERROR((AE_INFO,
 373                             "Please send DMI info to linux-acpi@vger.kernel.org\n"
 374                             "If system does not work as expected, please boot with acpi=copy_dsdt"));
 375
 376                 /* Disable further error messages */
 377
 378                 acpi_gbl_original_dsdt_header.length = acpi_gbl_DSDT->length;
 379                 acpi_gbl_original_dsdt_header.checksum =
 380                     acpi_gbl_DSDT->checksum;
 381         }
 382 }
 383
 384 /*******************************************************************************
 385  *
 386  * FUNCTION:    acpi_tb_copy_dsdt
 387  *
 388  * PARAMETERS:  table_desc          - Installed table to copy
 389  *
 390  * RETURN:      None
 391  *
 392  * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 393  *              Some very bad BIOSs are known to either corrupt the DSDT or
 394  *              install a new, bad DSDT. This copy works around the problem.
 395  *
 396  ******************************************************************************/
 397
 398 struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
 399 {
 400         struct acpi_table_header *new_table;
 401         struct acpi_table_desc *table_desc;
 402
 403         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 404
 405         new_table = ACPI_ALLOCATE(table_desc->length);
 406         if (!new_table) {
 407                 ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
 408                             table_desc->length));
 409                 return (NULL);
 410         }
 411
 412         ACPI_MEMCPY(new_table, table_desc->pointer, table_desc->length);
 413         acpi_tb_delete_table(table_desc);
 414         table_desc->pointer = new_table;
 415         table_desc->flags = ACPI_TABLE_ORIGIN_ALLOCATED;
 416
 417         ACPI_INFO((AE_INFO,
 418                    "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
 419                    new_table->length));
 420
 421         return (new_table);
 422 }
 423
 424 /*******************************************************************************
 425  *
 426  * FUNCTION:    acpi_tb_install_table
 427  *
 428  * PARAMETERS:  Address                 - Physical address of DSDT or FACS
 429  *              Signature               - Table signature, NULL if no need to
 430  *                                        match
 431  *              table_index             - Index into root table array
 432  *
 433  * RETURN:      None
 434  *
 435  * DESCRIPTION: Install an ACPI table into the global data structure. The
 436  *              table override mechanism is implemented here to allow the host
 437  *              OS to replace any table before it is installed in the root
 438  *              table array.
 439  *
 440  ******************************************************************************/
 441
 442 void
 443 acpi_tb_install_table(acpi_physical_address address,
 444                       char *signature, u32 table_index)
 445 {
 446         u8 flags;
 447         acpi_status status;
 448         struct acpi_table_header *table_to_install;
 449         struct acpi_table_header *mapped_table;
 450         struct acpi_table_header *override_table = NULL;
 451
 452         if (!address) {
 453                 ACPI_ERROR((AE_INFO,
 454                             "Null physical address for ACPI table [%s]",
 455                             signature));
 456                 return;
 457         }
 458
 459         /* Map just the table header */
 460
 461         mapped_table =
 462             acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 463         if (!mapped_table) {
 464                 return;
 465         }
 466
 467         /* If a particular signature is expected (DSDT/FACS), it must match */
 468
 469         if (signature && !ACPI_COMPARE_NAME(mapped_table->signature, signature)) {
 470                 ACPI_ERROR((AE_INFO,
 471                             "Invalid signature 0x%X for ACPI table, expected [%s]",
 472                             *ACPI_CAST_PTR(u32, mapped_table->signature),
 473                             signature));
 474                 goto unmap_and_exit;
 475         }
 476
 477         /*
 478          * ACPI Table Override:
 479          *
 480          * Before we install the table, let the host OS override it with a new
 481          * one if desired. Any table within the RSDT/XSDT can be replaced,
 482          * including the DSDT which is pointed to by the FADT.
 483          */
 484         status = acpi_os_table_override(mapped_table, &override_table);
 485         if (ACPI_SUCCESS(status) && override_table) {
 486                 ACPI_INFO((AE_INFO,
 487                            "%4.4s @ 0x%8.8X%8.8X Table override, replaced with:",
 488                            mapped_table->signature, ACPI_FORMAT_UINT64(address)));
 489
 490                 acpi_gbl_root_table_list.tables[table_index].pointer =
 491                     override_table;
 492                 address = ACPI_PTR_TO_PHYSADDR(override_table);
 493
 494                 table_to_install = override_table;
 495                 flags = ACPI_TABLE_ORIGIN_OVERRIDE;
 496         } else {
 497                 table_to_install = mapped_table;
 498                 flags = ACPI_TABLE_ORIGIN_MAPPED;
 499         }
 500
 501         /* Initialize the table entry */
 502
 503         acpi_gbl_root_table_list.tables[table_index].address = address;
 504         acpi_gbl_root_table_list.tables[table_index].length =
 505             table_to_install->length;
 506         acpi_gbl_root_table_list.tables[table_index].flags = flags;
 507
 508         ACPI_MOVE_32_TO_32(&
 509                            (acpi_gbl_root_table_list.tables[table_index].
 510                             signature), table_to_install->signature);
 511
 512         acpi_tb_print_table_header(address, table_to_install);
 513
 514         if (table_index == ACPI_TABLE_INDEX_DSDT) {
 515
 516                 /* Global integer width is based upon revision of the DSDT */
 517
 518                 acpi_ut_set_integer_width(table_to_install->revision);
 519         }
 520
 521       unmap_and_exit:
 522         acpi_os_unmap_memory(mapped_table, sizeof(struct acpi_table_header));
 523 }
 524
 525 /*******************************************************************************
 526  *
 527  * FUNCTION:    acpi_tb_get_root_table_entry
 528  *
 529  * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 530  *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 531  *
 532  * RETURN:      Physical address extracted from the root table
 533  *
 534  * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 535  *              both 32-bit and 64-bit platforms
 536  *
 537  * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 538  *              64-bit platforms.
 539  *
 540  ******************************************************************************/
 541
 542 static acpi_physical_address
 543 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
 544 {
 545         u64 address64;
 546
 547         /*
 548          * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
 549          * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
 550          */
 551         if (table_entry_size == sizeof(u32)) {
 552                 /*
 553                  * 32-bit platform, RSDT: Return 32-bit table entry
 554                  * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
 555                  */
 556                 return ((acpi_physical_address)
 557                         (*ACPI_CAST_PTR(u32, table_entry)));
 558         } else {
 559                 /*
 560                  * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
 561                  * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
 562                  *  return 64-bit
 563                  */
 564                 ACPI_MOVE_64_TO_64(&address64, table_entry);
 565
 566 #if ACPI_MACHINE_WIDTH == 32
 567                 if (address64 > ACPI_UINT32_MAX) {
 568
 569                         /* Will truncate 64-bit address to 32 bits, issue warning */
 570
 571                         ACPI_WARNING((AE_INFO,
 572                                       "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
 573                                       " truncating",
 574                                       ACPI_FORMAT_UINT64(address64)));
 575                 }
 576 #endif
 577                 return ((acpi_physical_address) (address64));
 578         }
 579 }
 580
 581 /*******************************************************************************
 582  *
 583  * FUNCTION:    acpi_tb_parse_root_table
 584  *
 585  * PARAMETERS:  Rsdp                    - Pointer to the RSDP
 586  *
 587  * RETURN:      Status
 588  *
 589  * DESCRIPTION: This function is called to parse the Root System Description
 590  *              Table (RSDT or XSDT)
 591  *
 592  * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 593  *              be mapped and cannot be copied because it contains the actual
 594  *              memory location of the ACPI Global Lock.
 595  *
 596  ******************************************************************************/
 597
 598 acpi_status __init
 599 acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 600 {
 601         struct acpi_table_rsdp *rsdp;
 602         u32 table_entry_size;
 603         u32 i;
 604         u32 table_count;
 605         struct acpi_table_header *table;
 606         acpi_physical_address address;
 607         acpi_physical_address uninitialized_var(rsdt_address);
 608         u32 length;
 609         u8 *table_entry;
 610         acpi_status status;
 611
 612         ACPI_FUNCTION_TRACE(tb_parse_root_table);
 613
 614         /*
 615          * Map the entire RSDP and extract the address of the RSDT or XSDT
 616          */
 617         rsdp = acpi_os_map_memory(rsdp_address, sizeof(struct acpi_table_rsdp));
 618         if (!rsdp) {
 619                 return_ACPI_STATUS(AE_NO_MEMORY);
 620         }
 621
 622         acpi_tb_print_table_header(rsdp_address,
 623                                    ACPI_CAST_PTR(struct acpi_table_header,
 624                                                  rsdp));
 625
 626         /* Differentiate between RSDT and XSDT root tables */
 627
 628         if (rsdp->revision > 1 && rsdp->xsdt_physical_address
 629                         && !acpi_rsdt_forced) {
 630                 /*
 631                  * Root table is an XSDT (64-bit physical addresses). We must use the
 632                  * XSDT if the revision is > 1 and the XSDT pointer is present, as per
 633                  * the ACPI specification.
 634                  */
 635                 address = (acpi_physical_address) rsdp->xsdt_physical_address;
 636                 table_entry_size = sizeof(u64);
 637                 rsdt_address = (acpi_physical_address)
 638                                         rsdp->rsdt_physical_address;
 639         } else {
 640                 /* Root table is an RSDT (32-bit physical addresses) */
 641
 642                 address = (acpi_physical_address) rsdp->rsdt_physical_address;
 643                 table_entry_size = sizeof(u32);
 644         }
 645
 646         /*
 647          * It is not possible to map more than one entry in some environments,
 648          * so unmap the RSDP here before mapping other tables
 649          */
 650         acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));
 651
 652         if (table_entry_size == sizeof(u64)) {
 653                 if (acpi_tb_check_xsdt(address) == AE_NULL_ENTRY) {
 654                         /* XSDT has NULL entry, RSDT is used */
 655                         address = rsdt_address;
 656                         table_entry_size = sizeof(u32);
 657                         ACPI_WARNING((AE_INFO, "BIOS XSDT has NULL entry, "
 658                                         "using RSDT"));
 659                 }
 660         }
 661         /* Map the RSDT/XSDT table header to get the full table length */
 662
 663         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 664         if (!table) {
 665                 return_ACPI_STATUS(AE_NO_MEMORY);
 666         }
 667
 668         acpi_tb_print_table_header(address, table);
 669
 670         /* Get the length of the full table, verify length and map entire table */
 671
 672         length = table->length;
 673         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 674
 675         if (length < sizeof(struct acpi_table_header)) {
 676                 ACPI_ERROR((AE_INFO, "Invalid length 0x%X in RSDT/XSDT",
 677                             length));
 678                 return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
 679         }
 680
 681         table = acpi_os_map_memory(address, length);
 682         if (!table) {
 683                 return_ACPI_STATUS(AE_NO_MEMORY);
 684         }
 685
 686         /* Validate the root table checksum */
 687
 688         status = acpi_tb_verify_checksum(table, length);
 689         if (ACPI_FAILURE(status)) {
 690                 acpi_os_unmap_memory(table, length);
 691                 return_ACPI_STATUS(status);
 692         }
 693
 694         /* Calculate the number of tables described in the root table */
 695
 696         table_count = (u32)((table->length - sizeof(struct acpi_table_header)) /
 697                             table_entry_size);
 698         /*
 699          * First two entries in the table array are reserved for the DSDT
 700          * and FACS, which are not actually present in the RSDT/XSDT - they
 701          * come from the FADT
 702          */
 703         table_entry =
 704             ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 705         acpi_gbl_root_table_list.current_table_count = 2;
 706
 707         /*
 708          * Initialize the root table array from the RSDT/XSDT
 709          */
 710         for (i = 0; i < table_count; i++) {
 711                 if (acpi_gbl_root_table_list.current_table_count >=
 712                     acpi_gbl_root_table_list.max_table_count) {
 713
 714                         /* There is no more room in the root table array, attempt resize */
 715
 716                         status = acpi_tb_resize_root_table_list();
 717                         if (ACPI_FAILURE(status)) {
 718                                 ACPI_WARNING((AE_INFO,
 719                                               "Truncating %u table entries!",
 720                                               (unsigned) (table_count -
 721                                                (acpi_gbl_root_table_list.
 722                                                           current_table_count -
 723                                                           2))));
 724                                 break;
 725                         }
 726                 }
 727
 728                 /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */
 729
 730                 acpi_gbl_root_table_list.tables[acpi_gbl_root_table_list.
 731                                                 current_table_count].address =
 732                     acpi_tb_get_root_table_entry(table_entry, table_entry_size);
 733
 734                 table_entry += table_entry_size;
 735                 acpi_gbl_root_table_list.current_table_count++;
 736         }
 737
 738         /*
 739          * It is not possible to map more than one entry in some environments,
 740          * so unmap the root table here before mapping other tables
 741          */
 742         acpi_os_unmap_memory(table, length);
 743
 744         /*
 745          * Complete the initialization of the root table array by examining
 746          * the header of each table
 747          */
 748         for (i = 2; i < acpi_gbl_root_table_list.current_table_count; i++) {
 749                 acpi_tb_install_table(acpi_gbl_root_table_list.tables[i].
 750                                       address, NULL, i);
 751
 752                 /* Special case for FADT - get the DSDT and FACS */
 753
 754                 if (ACPI_COMPARE_NAME
 755                     (&acpi_gbl_root_table_list.tables[i].signature,
 756                      ACPI_SIG_FADT)) {
 757                         acpi_tb_parse_fadt(i);
 758                 }
 759         }
 760
 761         return_ACPI_STATUS(AE_OK);
 762 }