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