Pileus Git - ~andy/linux/blob - drivers/acpi/acpica/tbutils.c

   1 /******************************************************************************
   2  *
   3  * Module Name: tbutils   - table utilities
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2012, 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 #if (!ACPI_REDUCED_HARDWARE)
 122 /*******************************************************************************
 123  *
 124  * FUNCTION:    acpi_tb_initialize_facs
 125  *
 126  * PARAMETERS:  None
 127  *
 128  * RETURN:      Status
 129  *
 130  * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
 131  *              for accessing the Global Lock and Firmware Waking Vector
 132  *
 133  ******************************************************************************/
 134
 135 acpi_status acpi_tb_initialize_facs(void)
 136 {
 137         acpi_status status;
 138
 139         /* If Hardware Reduced flag is set, there is no FACS */
 140
 141         if (acpi_gbl_reduced_hardware) {
 142                 acpi_gbl_FACS = NULL;
 143                 return (AE_OK);
 144         }
 145
 146         status = acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 147                                          ACPI_CAST_INDIRECT_PTR(struct
 148                                                                 acpi_table_header,
 149                                                                 &acpi_gbl_FACS));
 150         return status;
 151 }
 152 #endif                          /* !ACPI_REDUCED_HARDWARE */
 153
 154 /*******************************************************************************
 155  *
 156  * FUNCTION:    acpi_tb_tables_loaded
 157  *
 158  * PARAMETERS:  None
 159  *
 160  * RETURN:      TRUE if required ACPI tables are loaded
 161  *
 162  * DESCRIPTION: Determine if the minimum required ACPI tables are present
 163  *              (FADT, FACS, DSDT)
 164  *
 165  ******************************************************************************/
 166
 167 u8 acpi_tb_tables_loaded(void)
 168 {
 169
 170         if (acpi_gbl_root_table_list.current_table_count >= 3) {
 171                 return (TRUE);
 172         }
 173
 174         return (FALSE);
 175 }
 176
 177 /*******************************************************************************
 178  *
 179  * FUNCTION:    acpi_tb_fix_string
 180  *
 181  * PARAMETERS:  String              - String to be repaired
 182  *              Length              - Maximum length
 183  *
 184  * RETURN:      None
 185  *
 186  * DESCRIPTION: Replace every non-printable or non-ascii byte in the string
 187  *              with a question mark '?'.
 188  *
 189  ******************************************************************************/
 190
 191 static void acpi_tb_fix_string(char *string, acpi_size length)
 192 {
 193
 194         while (length && *string) {
 195                 if (!ACPI_IS_PRINT(*string)) {
 196                         *string = '?';
 197                 }
 198                 string++;
 199                 length--;
 200         }
 201 }
 202
 203 /*******************************************************************************
 204  *
 205  * FUNCTION:    acpi_tb_cleanup_table_header
 206  *
 207  * PARAMETERS:  out_header          - Where the cleaned header is returned
 208  *              Header              - Input ACPI table header
 209  *
 210  * RETURN:      Returns the cleaned header in out_header
 211  *
 212  * DESCRIPTION: Copy the table header and ensure that all "string" fields in
 213  *              the header consist of printable characters.
 214  *
 215  ******************************************************************************/
 216
 217 static void
 218 acpi_tb_cleanup_table_header(struct acpi_table_header *out_header,
 219                              struct acpi_table_header *header)
 220 {
 221
 222         ACPI_MEMCPY(out_header, header, sizeof(struct acpi_table_header));
 223
 224         acpi_tb_fix_string(out_header->signature, ACPI_NAME_SIZE);
 225         acpi_tb_fix_string(out_header->oem_id, ACPI_OEM_ID_SIZE);
 226         acpi_tb_fix_string(out_header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
 227         acpi_tb_fix_string(out_header->asl_compiler_id, ACPI_NAME_SIZE);
 228 }
 229
 230 /*******************************************************************************
 231  *
 232  * FUNCTION:    acpi_tb_print_table_header
 233  *
 234  * PARAMETERS:  Address             - Table physical address
 235  *              Header              - Table header
 236  *
 237  * RETURN:      None
 238  *
 239  * DESCRIPTION: Print an ACPI table header. Special cases for FACS and RSDP.
 240  *
 241  ******************************************************************************/
 242
 243 void
 244 acpi_tb_print_table_header(acpi_physical_address address,
 245                            struct acpi_table_header *header)
 246 {
 247         struct acpi_table_header local_header;
 248
 249         /*
 250          * The reason that the Address is cast to a void pointer is so that we
 251          * can use %p which will work properly on both 32-bit and 64-bit hosts.
 252          */
 253         if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_FACS)) {
 254
 255                 /* FACS only has signature and length fields */
 256
 257                 ACPI_INFO((AE_INFO, "%4.4s %p %05X",
 258                            header->signature, ACPI_CAST_PTR(void, address),
 259                            header->length));
 260         } else if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_RSDP)) {
 261
 262                 /* RSDP has no common fields */
 263
 264                 ACPI_MEMCPY(local_header.oem_id,
 265                             ACPI_CAST_PTR(struct acpi_table_rsdp,
 266                                           header)->oem_id, ACPI_OEM_ID_SIZE);
 267                 acpi_tb_fix_string(local_header.oem_id, ACPI_OEM_ID_SIZE);
 268
 269                 ACPI_INFO((AE_INFO, "RSDP %p %05X (v%.2d %6.6s)",
 270                            ACPI_CAST_PTR (void, address),
 271                            (ACPI_CAST_PTR(struct acpi_table_rsdp, header)->
 272                             revision >
 273                             0) ? ACPI_CAST_PTR(struct acpi_table_rsdp,
 274                                                header)->length : 20,
 275                            ACPI_CAST_PTR(struct acpi_table_rsdp,
 276                                          header)->revision,
 277                            local_header.oem_id));
 278         } else {
 279                 /* Standard ACPI table with full common header */
 280
 281                 acpi_tb_cleanup_table_header(&local_header, header);
 282
 283                 ACPI_INFO((AE_INFO,
 284                            "%4.4s %p %05X (v%.2d %6.6s %8.8s %08X %4.4s %08X)",
 285                            local_header.signature, ACPI_CAST_PTR(void, address),
 286                            local_header.length, local_header.revision,
 287                            local_header.oem_id, local_header.oem_table_id,
 288                            local_header.oem_revision,
 289                            local_header.asl_compiler_id,
 290                            local_header.asl_compiler_revision));
 291
 292         }
 293 }
 294
 295 /*******************************************************************************
 296  *
 297  * FUNCTION:    acpi_tb_validate_checksum
 298  *
 299  * PARAMETERS:  Table               - ACPI table to verify
 300  *              Length              - Length of entire table
 301  *
 302  * RETURN:      Status
 303  *
 304  * DESCRIPTION: Verifies that the table checksums to zero. Optionally returns
 305  *              exception on bad checksum.
 306  *
 307  ******************************************************************************/
 308
 309 acpi_status acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length)
 310 {
 311         u8 checksum;
 312
 313         /* Compute the checksum on the table */
 314
 315         checksum = acpi_tb_checksum(ACPI_CAST_PTR(u8, table), length);
 316
 317         /* Checksum ok? (should be zero) */
 318
 319         if (checksum) {
 320                 ACPI_WARNING((AE_INFO,
 321                               "Incorrect checksum in table [%4.4s] - 0x%2.2X, should be 0x%2.2X",
 322                               table->signature, table->checksum,
 323                               (u8) (table->checksum - checksum)));
 324
 325 #if (ACPI_CHECKSUM_ABORT)
 326
 327                 return (AE_BAD_CHECKSUM);
 328 #endif
 329         }
 330
 331         return (AE_OK);
 332 }
 333
 334 /*******************************************************************************
 335  *
 336  * FUNCTION:    acpi_tb_checksum
 337  *
 338  * PARAMETERS:  Buffer          - Pointer to memory region to be checked
 339  *              Length          - Length of this memory region
 340  *
 341  * RETURN:      Checksum (u8)
 342  *
 343  * DESCRIPTION: Calculates circular checksum of memory region.
 344  *
 345  ******************************************************************************/
 346
 347 u8 acpi_tb_checksum(u8 *buffer, u32 length)
 348 {
 349         u8 sum = 0;
 350         u8 *end = buffer + length;
 351
 352         while (buffer < end) {
 353                 sum = (u8) (sum + *(buffer++));
 354         }
 355
 356         return sum;
 357 }
 358
 359 /*******************************************************************************
 360  *
 361  * FUNCTION:    acpi_tb_check_dsdt_header
 362  *
 363  * PARAMETERS:  None
 364  *
 365  * RETURN:      None
 366  *
 367  * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 368  *              if the DSDT has been replaced from outside the OS and/or if
 369  *              the DSDT header has been corrupted.
 370  *
 371  ******************************************************************************/
 372
 373 void acpi_tb_check_dsdt_header(void)
 374 {
 375
 376         /* Compare original length and checksum to current values */
 377
 378         if (acpi_gbl_original_dsdt_header.length != acpi_gbl_DSDT->length ||
 379             acpi_gbl_original_dsdt_header.checksum != acpi_gbl_DSDT->checksum) {
 380                 ACPI_ERROR((AE_INFO,
 381                             "The DSDT has been corrupted or replaced - old, new headers below"));
 382                 acpi_tb_print_table_header(0, &acpi_gbl_original_dsdt_header);
 383                 acpi_tb_print_table_header(0, acpi_gbl_DSDT);
 384
 385                 ACPI_ERROR((AE_INFO,
 386                             "Please send DMI info to linux-acpi@vger.kernel.org\n"
 387                             "If system does not work as expected, please boot with acpi=copy_dsdt"));
 388
 389                 /* Disable further error messages */
 390
 391                 acpi_gbl_original_dsdt_header.length = acpi_gbl_DSDT->length;
 392                 acpi_gbl_original_dsdt_header.checksum =
 393                     acpi_gbl_DSDT->checksum;
 394         }
 395 }
 396
 397 /*******************************************************************************
 398  *
 399  * FUNCTION:    acpi_tb_copy_dsdt
 400  *
 401  * PARAMETERS:  table_desc          - Installed table to copy
 402  *
 403  * RETURN:      None
 404  *
 405  * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 406  *              Some very bad BIOSs are known to either corrupt the DSDT or
 407  *              install a new, bad DSDT. This copy works around the problem.
 408  *
 409  ******************************************************************************/
 410
 411 struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
 412 {
 413         struct acpi_table_header *new_table;
 414         struct acpi_table_desc *table_desc;
 415
 416         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 417
 418         new_table = ACPI_ALLOCATE(table_desc->length);
 419         if (!new_table) {
 420                 ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
 421                             table_desc->length));
 422                 return (NULL);
 423         }
 424
 425         ACPI_MEMCPY(new_table, table_desc->pointer, table_desc->length);
 426         acpi_tb_delete_table(table_desc);
 427         table_desc->pointer = new_table;
 428         table_desc->flags = ACPI_TABLE_ORIGIN_ALLOCATED;
 429
 430         ACPI_INFO((AE_INFO,
 431                    "Forced DSDT copy: length 0x%05X copied locally, original unmapped",
 432                    new_table->length));
 433
 434         return (new_table);
 435 }
 436
 437 /*******************************************************************************
 438  *
 439  * FUNCTION:    acpi_tb_install_table
 440  *
 441  * PARAMETERS:  Address                 - Physical address of DSDT or FACS
 442  *              Signature               - Table signature, NULL if no need to
 443  *                                        match
 444  *              table_index             - Index into root table array
 445  *
 446  * RETURN:      None
 447  *
 448  * DESCRIPTION: Install an ACPI table into the global data structure. The
 449  *              table override mechanism is called to allow the host
 450  *              OS to replace any table before it is installed in the root
 451  *              table array.
 452  *
 453  ******************************************************************************/
 454
 455 void
 456 acpi_tb_install_table(acpi_physical_address address,
 457                       char *signature, u32 table_index)
 458 {
 459         struct acpi_table_header *table;
 460         struct acpi_table_header *final_table;
 461         struct acpi_table_desc *table_desc;
 462
 463         if (!address) {
 464                 ACPI_ERROR((AE_INFO,
 465                             "Null physical address for ACPI table [%s]",
 466                             signature));
 467                 return;
 468         }
 469
 470         /* Map just the table header */
 471
 472         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 473         if (!table) {
 474                 ACPI_ERROR((AE_INFO,
 475                             "Could not map memory for table [%s] at %p",
 476                             signature, ACPI_CAST_PTR(void, address)));
 477                 return;
 478         }
 479
 480         /* If a particular signature is expected (DSDT/FACS), it must match */
 481
 482         if (signature && !ACPI_COMPARE_NAME(table->signature, signature)) {
 483                 ACPI_ERROR((AE_INFO,
 484                             "Invalid signature 0x%X for ACPI table, expected [%s]",
 485                             *ACPI_CAST_PTR(u32, table->signature), signature));
 486                 goto unmap_and_exit;
 487         }
 488
 489         /*
 490          * Initialize the table entry. Set the pointer to NULL, since the
 491          * table is not fully mapped at this time.
 492          */
 493         table_desc = &acpi_gbl_root_table_list.tables[table_index];
 494
 495         table_desc->address = address;
 496         table_desc->pointer = NULL;
 497         table_desc->length = table->length;
 498         table_desc->flags = ACPI_TABLE_ORIGIN_MAPPED;
 499         ACPI_MOVE_32_TO_32(table_desc->signature.ascii, table->signature);
 500
 501         /*
 502          * ACPI Table Override:
 503          *
 504          * Before we install the table, let the host OS override it with a new
 505          * one if desired. Any table within the RSDT/XSDT can be replaced,
 506          * including the DSDT which is pointed to by the FADT.
 507          *
 508          * NOTE: If the table is overridden, then final_table will contain a
 509          * mapped pointer to the full new table. If the table is not overridden,
 510          * or if there has been a physical override, then the table will be
 511          * fully mapped later (in verify table). In any case, we must
 512          * unmap the header that was mapped above.
 513          */
 514         final_table = acpi_tb_table_override(table, table_desc);
 515         if (!final_table) {
 516                 final_table = table;    /* There was no override */
 517         }
 518
 519         acpi_tb_print_table_header(table_desc->address, final_table);
 520
 521         /* Set the global integer width (based upon revision of the DSDT) */
 522
 523         if (table_index == ACPI_TABLE_INDEX_DSDT) {
 524                 acpi_ut_set_integer_width(final_table->revision);
 525         }
 526
 527         /*
 528          * If we have a physical override during this early loading of the ACPI
 529          * tables, unmap the table for now. It will be mapped again later when
 530          * it is actually used. This supports very early loading of ACPI tables,
 531          * before virtual memory is fully initialized and running within the
 532          * host OS. Note: A logical override has the ACPI_TABLE_ORIGIN_OVERRIDE
 533          * flag set and will not be deleted below.
 534          */
 535         if (final_table != table) {
 536                 acpi_tb_delete_table(table_desc);
 537         }
 538
 539       unmap_and_exit:
 540
 541         /* Always unmap the table header that we mapped above */
 542
 543         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 544 }
 545
 546 /*******************************************************************************
 547  *
 548  * FUNCTION:    acpi_tb_get_root_table_entry
 549  *
 550  * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 551  *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 552  *
 553  * RETURN:      Physical address extracted from the root table
 554  *
 555  * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 556  *              both 32-bit and 64-bit platforms
 557  *
 558  * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 559  *              64-bit platforms.
 560  *
 561  ******************************************************************************/
 562
 563 static acpi_physical_address
 564 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
 565 {
 566         u64 address64;
 567
 568         /*
 569          * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
 570          * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
 571          */
 572         if (table_entry_size == sizeof(u32)) {
 573                 /*
 574                  * 32-bit platform, RSDT: Return 32-bit table entry
 575                  * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
 576                  */
 577                 return ((acpi_physical_address)
 578                         (*ACPI_CAST_PTR(u32, table_entry)));
 579         } else {
 580                 /*
 581                  * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
 582                  * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
 583                  *  return 64-bit
 584                  */
 585                 ACPI_MOVE_64_TO_64(&address64, table_entry);
 586
 587 #if ACPI_MACHINE_WIDTH == 32
 588                 if (address64 > ACPI_UINT32_MAX) {
 589
 590                         /* Will truncate 64-bit address to 32 bits, issue warning */
 591
 592                         ACPI_WARNING((AE_INFO,
 593                                       "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
 594                                       " truncating",
 595                                       ACPI_FORMAT_UINT64(address64)));
 596                 }
 597 #endif
 598                 return ((acpi_physical_address) (address64));
 599         }
 600 }
 601
 602 /*******************************************************************************
 603  *
 604  * FUNCTION:    acpi_tb_parse_root_table
 605  *
 606  * PARAMETERS:  Rsdp                    - Pointer to the RSDP
 607  *
 608  * RETURN:      Status
 609  *
 610  * DESCRIPTION: This function is called to parse the Root System Description
 611  *              Table (RSDT or XSDT)
 612  *
 613  * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 614  *              be mapped and cannot be copied because it contains the actual
 615  *              memory location of the ACPI Global Lock.
 616  *
 617  ******************************************************************************/
 618
 619 acpi_status __init
 620 acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 621 {
 622         struct acpi_table_rsdp *rsdp;
 623         u32 table_entry_size;
 624         u32 i;
 625         u32 table_count;
 626         struct acpi_table_header *table;
 627         acpi_physical_address address;
 628         acpi_physical_address uninitialized_var(rsdt_address);
 629         u32 length;
 630         u8 *table_entry;
 631         acpi_status status;
 632
 633         ACPI_FUNCTION_TRACE(tb_parse_root_table);
 634
 635         /*
 636          * Map the entire RSDP and extract the address of the RSDT or XSDT
 637          */
 638         rsdp = acpi_os_map_memory(rsdp_address, sizeof(struct acpi_table_rsdp));
 639         if (!rsdp) {
 640                 return_ACPI_STATUS(AE_NO_MEMORY);
 641         }
 642
 643         acpi_tb_print_table_header(rsdp_address,
 644                                    ACPI_CAST_PTR(struct acpi_table_header,
 645                                                  rsdp));
 646
 647         /* Differentiate between RSDT and XSDT root tables */
 648
 649         if (rsdp->revision > 1 && rsdp->xsdt_physical_address
 650                         && !acpi_rsdt_forced) {
 651                 /*
 652                  * Root table is an XSDT (64-bit physical addresses). We must use the
 653                  * XSDT if the revision is > 1 and the XSDT pointer is present, as per
 654                  * the ACPI specification.
 655                  */
 656                 address = (acpi_physical_address) rsdp->xsdt_physical_address;
 657                 table_entry_size = sizeof(u64);
 658                 rsdt_address = (acpi_physical_address)
 659                                         rsdp->rsdt_physical_address;
 660         } else {
 661                 /* Root table is an RSDT (32-bit physical addresses) */
 662
 663                 address = (acpi_physical_address) rsdp->rsdt_physical_address;
 664                 table_entry_size = sizeof(u32);
 665         }
 666
 667         /*
 668          * It is not possible to map more than one entry in some environments,
 669          * so unmap the RSDP here before mapping other tables
 670          */
 671         acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));
 672
 673         if (table_entry_size == sizeof(u64)) {
 674                 if (acpi_tb_check_xsdt(address) == AE_NULL_ENTRY) {
 675                         /* XSDT has NULL entry, RSDT is used */
 676                         address = rsdt_address;
 677                         table_entry_size = sizeof(u32);
 678                         ACPI_WARNING((AE_INFO, "BIOS XSDT has NULL entry, "
 679                                         "using RSDT"));
 680                 }
 681         }
 682         /* Map the RSDT/XSDT table header to get the full table length */
 683
 684         table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
 685         if (!table) {
 686                 return_ACPI_STATUS(AE_NO_MEMORY);
 687         }
 688
 689         acpi_tb_print_table_header(address, table);
 690
 691         /* Get the length of the full table, verify length and map entire table */
 692
 693         length = table->length;
 694         acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
 695
 696         if (length < sizeof(struct acpi_table_header)) {
 697                 ACPI_ERROR((AE_INFO, "Invalid length 0x%X in RSDT/XSDT",
 698                             length));
 699                 return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
 700         }
 701
 702         table = acpi_os_map_memory(address, length);
 703         if (!table) {
 704                 return_ACPI_STATUS(AE_NO_MEMORY);
 705         }
 706
 707         /* Validate the root table checksum */
 708
 709         status = acpi_tb_verify_checksum(table, length);
 710         if (ACPI_FAILURE(status)) {
 711                 acpi_os_unmap_memory(table, length);
 712                 return_ACPI_STATUS(status);
 713         }
 714
 715         /* Calculate the number of tables described in the root table */
 716
 717         table_count = (u32)((table->length - sizeof(struct acpi_table_header)) /
 718                             table_entry_size);
 719         /*
 720          * First two entries in the table array are reserved for the DSDT
 721          * and FACS, which are not actually present in the RSDT/XSDT - they
 722          * come from the FADT
 723          */
 724         table_entry =
 725             ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
 726         acpi_gbl_root_table_list.current_table_count = 2;
 727
 728         /*
 729          * Initialize the root table array from the RSDT/XSDT
 730          */
 731         for (i = 0; i < table_count; i++) {
 732                 if (acpi_gbl_root_table_list.current_table_count >=
 733                     acpi_gbl_root_table_list.max_table_count) {
 734
 735                         /* There is no more room in the root table array, attempt resize */
 736
 737                         status = acpi_tb_resize_root_table_list();
 738                         if (ACPI_FAILURE(status)) {
 739                                 ACPI_WARNING((AE_INFO,
 740                                               "Truncating %u table entries!",
 741                                               (unsigned) (table_count -
 742                                                (acpi_gbl_root_table_list.
 743                                                           current_table_count -
 744                                                           2))));
 745                                 break;
 746                         }
 747                 }
 748
 749                 /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */
 750
 751                 acpi_gbl_root_table_list.tables[acpi_gbl_root_table_list.
 752                                                 current_table_count].address =
 753                     acpi_tb_get_root_table_entry(table_entry, table_entry_size);
 754
 755                 table_entry += table_entry_size;
 756                 acpi_gbl_root_table_list.current_table_count++;
 757         }
 758
 759         /*
 760          * It is not possible to map more than one entry in some environments,
 761          * so unmap the root table here before mapping other tables
 762          */
 763         acpi_os_unmap_memory(table, length);
 764
 765         /*
 766          * Complete the initialization of the root table array by examining
 767          * the header of each table
 768          */
 769         for (i = 2; i < acpi_gbl_root_table_list.current_table_count; i++) {
 770                 acpi_tb_install_table(acpi_gbl_root_table_list.tables[i].
 771                                       address, NULL, i);
 772
 773                 /* Special case for FADT - get the DSDT and FACS */
 774
 775                 if (ACPI_COMPARE_NAME
 776                     (&acpi_gbl_root_table_list.tables[i].signature,
 777                      ACPI_SIG_FADT)) {
 778                         acpi_tb_parse_fadt(i);
 779                 }
 780         }
 781
 782         return_ACPI_STATUS(AE_OK);
 783 }