xref: /openbmc/linux/drivers/acpi/acpica/tbxface.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /******************************************************************************
2  *
3  * Module Name: tbxface - Public interfaces to the ACPI subsystem
4  *                         ACPI table oriented interfaces
5  *
6  *****************************************************************************/
7 
8 /*
9  * Copyright (C) 2000 - 2008, Intel Corp.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44 
45 #include <acpi/acpi.h>
46 #include "accommon.h"
47 #include "acnamesp.h"
48 #include "actables.h"
49 
50 #define _COMPONENT          ACPI_TABLES
51 ACPI_MODULE_NAME("tbxface")
52 
53 /* Local prototypes */
54 static acpi_status acpi_tb_load_namespace(void);
55 
56 static int no_auto_ssdt;
57 
58 /*******************************************************************************
59  *
60  * FUNCTION:    acpi_allocate_root_table
61  *
62  * PARAMETERS:  initial_table_count - Size of initial_table_array, in number of
63  *                                    struct acpi_table_desc structures
64  *
65  * RETURN:      Status
66  *
67  * DESCRIPTION: Allocate a root table array. Used by i_aSL compiler and
68  *              acpi_initialize_tables.
69  *
70  ******************************************************************************/
71 
72 acpi_status acpi_allocate_root_table(u32 initial_table_count)
73 {
74 
75 	acpi_gbl_root_table_list.size = initial_table_count;
76 	acpi_gbl_root_table_list.flags = ACPI_ROOT_ALLOW_RESIZE;
77 
78 	return (acpi_tb_resize_root_table_list());
79 }
80 
81 /*******************************************************************************
82  *
83  * FUNCTION:    acpi_initialize_tables
84  *
85  * PARAMETERS:  initial_table_array - Pointer to an array of pre-allocated
86  *                                    struct acpi_table_desc structures. If NULL, the
87  *                                    array is dynamically allocated.
88  *              initial_table_count - Size of initial_table_array, in number of
89  *                                    struct acpi_table_desc structures
90  *              allow_realloc       - Flag to tell Table Manager if resize of
91  *                                    pre-allocated array is allowed. Ignored
92  *                                    if initial_table_array is NULL.
93  *
94  * RETURN:      Status
95  *
96  * DESCRIPTION: Initialize the table manager, get the RSDP and RSDT/XSDT.
97  *
98  * NOTE:        Allows static allocation of the initial table array in order
99  *              to avoid the use of dynamic memory in confined environments
100  *              such as the kernel boot sequence where it may not be available.
101  *
102  *              If the host OS memory managers are initialized, use NULL for
103  *              initial_table_array, and the table will be dynamically allocated.
104  *
105  ******************************************************************************/
106 
107 acpi_status __init
108 acpi_initialize_tables(struct acpi_table_desc * initial_table_array,
109 		       u32 initial_table_count, u8 allow_resize)
110 {
111 	acpi_physical_address rsdp_address;
112 	acpi_status status;
113 
114 	ACPI_FUNCTION_TRACE(acpi_initialize_tables);
115 
116 	/*
117 	 * Set up the Root Table Array
118 	 * Allocate the table array if requested
119 	 */
120 	if (!initial_table_array) {
121 		status = acpi_allocate_root_table(initial_table_count);
122 		if (ACPI_FAILURE(status)) {
123 			return_ACPI_STATUS(status);
124 		}
125 	} else {
126 		/* Root Table Array has been statically allocated by the host */
127 
128 		ACPI_MEMSET(initial_table_array, 0,
129 			    (acpi_size) initial_table_count *
130 			    sizeof(struct acpi_table_desc));
131 
132 		acpi_gbl_root_table_list.tables = initial_table_array;
133 		acpi_gbl_root_table_list.size = initial_table_count;
134 		acpi_gbl_root_table_list.flags = ACPI_ROOT_ORIGIN_UNKNOWN;
135 		if (allow_resize) {
136 			acpi_gbl_root_table_list.flags |=
137 			    ACPI_ROOT_ALLOW_RESIZE;
138 		}
139 	}
140 
141 	/* Get the address of the RSDP */
142 
143 	rsdp_address = acpi_os_get_root_pointer();
144 	if (!rsdp_address) {
145 		return_ACPI_STATUS(AE_NOT_FOUND);
146 	}
147 
148 	/*
149 	 * Get the root table (RSDT or XSDT) and extract all entries to the local
150 	 * Root Table Array. This array contains the information of the RSDT/XSDT
151 	 * in a common, more useable format.
152 	 */
153 	status =
154 	    acpi_tb_parse_root_table(rsdp_address, ACPI_TABLE_ORIGIN_MAPPED);
155 	return_ACPI_STATUS(status);
156 }
157 
158 /*******************************************************************************
159  *
160  * FUNCTION:    acpi_reallocate_root_table
161  *
162  * PARAMETERS:  None
163  *
164  * RETURN:      Status
165  *
166  * DESCRIPTION: Reallocate Root Table List into dynamic memory. Copies the
167  *              root list from the previously provided scratch area. Should
168  *              be called once dynamic memory allocation is available in the
169  *              kernel
170  *
171  ******************************************************************************/
172 acpi_status acpi_reallocate_root_table(void)
173 {
174 	struct acpi_table_desc *tables;
175 	acpi_size new_size;
176 
177 	ACPI_FUNCTION_TRACE(acpi_reallocate_root_table);
178 
179 	/*
180 	 * Only reallocate the root table if the host provided a static buffer
181 	 * for the table array in the call to acpi_initialize_tables.
182 	 */
183 	if (acpi_gbl_root_table_list.flags & ACPI_ROOT_ORIGIN_ALLOCATED) {
184 		return_ACPI_STATUS(AE_SUPPORT);
185 	}
186 
187 	new_size = ((acpi_size) acpi_gbl_root_table_list.count +
188 		    ACPI_ROOT_TABLE_SIZE_INCREMENT) *
189 	    sizeof(struct acpi_table_desc);
190 
191 	/* Create new array and copy the old array */
192 
193 	tables = ACPI_ALLOCATE_ZEROED(new_size);
194 	if (!tables) {
195 		return_ACPI_STATUS(AE_NO_MEMORY);
196 	}
197 
198 	ACPI_MEMCPY(tables, acpi_gbl_root_table_list.tables, new_size);
199 
200 	acpi_gbl_root_table_list.size = acpi_gbl_root_table_list.count;
201 	acpi_gbl_root_table_list.tables = tables;
202 	acpi_gbl_root_table_list.flags =
203 	    ACPI_ROOT_ORIGIN_ALLOCATED | ACPI_ROOT_ALLOW_RESIZE;
204 
205 	return_ACPI_STATUS(AE_OK);
206 }
207 
208 /*******************************************************************************
209  *
210  * FUNCTION:    acpi_load_table
211  *
212  * PARAMETERS:  table_ptr       - pointer to a buffer containing the entire
213  *                                table to be loaded
214  *
215  * RETURN:      Status
216  *
217  * DESCRIPTION: This function is called to load a table from the caller's
218  *              buffer. The buffer must contain an entire ACPI Table including
219  *              a valid header. The header fields will be verified, and if it
220  *              is determined that the table is invalid, the call will fail.
221  *
222  ******************************************************************************/
223 acpi_status acpi_load_table(struct acpi_table_header *table_ptr)
224 {
225 	acpi_status status;
226 	u32 table_index;
227 	struct acpi_table_desc table_desc;
228 
229 	if (!table_ptr)
230 		return AE_BAD_PARAMETER;
231 
232 	ACPI_MEMSET(&table_desc, 0, sizeof(struct acpi_table_desc));
233 	table_desc.pointer = table_ptr;
234 	table_desc.length = table_ptr->length;
235 	table_desc.flags = ACPI_TABLE_ORIGIN_UNKNOWN;
236 
237 	/*
238 	 * Install the new table into the local data structures
239 	 */
240 	status = acpi_tb_add_table(&table_desc, &table_index);
241 	if (ACPI_FAILURE(status)) {
242 		return status;
243 	}
244 	status = acpi_ns_load_table(table_index, acpi_gbl_root_node);
245 	return status;
246 }
247 
248 ACPI_EXPORT_SYMBOL(acpi_load_table)
249 
250 /******************************************************************************
251  *
252  * FUNCTION:    acpi_get_table_header
253  *
254  * PARAMETERS:  Signature           - ACPI signature of needed table
255  *              Instance            - Which instance (for SSDTs)
256  *              out_table_header    - The pointer to the table header to fill
257  *
258  * RETURN:      Status and pointer to mapped table header
259  *
260  * DESCRIPTION: Finds an ACPI table header.
261  *
262  * NOTE:        Caller is responsible in unmapping the header with
263  *              acpi_os_unmap_memory
264  *
265  *****************************************************************************/
266 acpi_status
267 acpi_get_table_header(char *signature,
268 		      u32 instance, struct acpi_table_header *out_table_header)
269 {
270        u32 i;
271        u32 j;
272 	struct acpi_table_header *header;
273 
274 	/* Parameter validation */
275 
276 	if (!signature || !out_table_header) {
277 		return (AE_BAD_PARAMETER);
278 	}
279 
280 	/*
281 	 * Walk the root table list
282 	 */
283 	for (i = 0, j = 0; i < acpi_gbl_root_table_list.count; i++) {
284 		if (!ACPI_COMPARE_NAME
285 		    (&(acpi_gbl_root_table_list.tables[i].signature),
286 		     signature)) {
287 			continue;
288 		}
289 
290 		if (++j < instance) {
291 			continue;
292 		}
293 
294 		if (!acpi_gbl_root_table_list.tables[i].pointer) {
295 			if ((acpi_gbl_root_table_list.tables[i].
296 			     flags & ACPI_TABLE_ORIGIN_MASK) ==
297 			    ACPI_TABLE_ORIGIN_MAPPED) {
298 				header =
299 				    acpi_os_map_memory(acpi_gbl_root_table_list.
300 						       tables[i].address,
301 						       sizeof(struct
302 							      acpi_table_header));
303 				if (!header) {
304 					return AE_NO_MEMORY;
305 				}
306 				ACPI_MEMCPY(out_table_header, header,
307 					    sizeof(struct acpi_table_header));
308 				acpi_os_unmap_memory(header,
309 						     sizeof(struct
310 							    acpi_table_header));
311 			} else {
312 				return AE_NOT_FOUND;
313 			}
314 		} else {
315 			ACPI_MEMCPY(out_table_header,
316 				    acpi_gbl_root_table_list.tables[i].pointer,
317 				    sizeof(struct acpi_table_header));
318 		}
319 		return (AE_OK);
320 	}
321 
322 	return (AE_NOT_FOUND);
323 }
324 
325 ACPI_EXPORT_SYMBOL(acpi_get_table_header)
326 
327 /******************************************************************************
328  *
329  * FUNCTION:    acpi_unload_table_id
330  *
331  * PARAMETERS:  id            - Owner ID of the table to be removed.
332  *
333  * RETURN:      Status
334  *
335  * DESCRIPTION: This routine is used to force the unload of a table (by id)
336  *
337  ******************************************************************************/
338 acpi_status acpi_unload_table_id(acpi_owner_id id)
339 {
340 	int i;
341 	acpi_status status = AE_NOT_EXIST;
342 
343 	ACPI_FUNCTION_TRACE(acpi_unload_table_id);
344 
345 	/* Find table in the global table list */
346 	for (i = 0; i < acpi_gbl_root_table_list.count; ++i) {
347 		if (id != acpi_gbl_root_table_list.tables[i].owner_id) {
348 			continue;
349 		}
350 		/*
351 		 * Delete all namespace objects owned by this table. Note that these
352 		 * objects can appear anywhere in the namespace by virtue of the AML
353 		 * "Scope" operator. Thus, we need to track ownership by an ID, not
354 		 * simply a position within the hierarchy
355 		 */
356 		acpi_tb_delete_namespace_by_owner(i);
357 		status = acpi_tb_release_owner_id(i);
358 		acpi_tb_set_table_loaded_flag(i, FALSE);
359 		break;
360 	}
361 	return_ACPI_STATUS(status);
362 }
363 
364 ACPI_EXPORT_SYMBOL(acpi_unload_table_id)
365 
366 /*******************************************************************************
367  *
368  * FUNCTION:    acpi_get_table_with_size
369  *
370  * PARAMETERS:  Signature           - ACPI signature of needed table
371  *              Instance            - Which instance (for SSDTs)
372  *              out_table           - Where the pointer to the table is returned
373  *
374  * RETURN:      Status and pointer to table
375  *
376  * DESCRIPTION: Finds and verifies an ACPI table.
377  *
378  *****************************************************************************/
379 acpi_status
380 acpi_get_table_with_size(char *signature,
381 	       u32 instance, struct acpi_table_header **out_table,
382 	       acpi_size *tbl_size)
383 {
384        u32 i;
385        u32 j;
386 	acpi_status status;
387 
388 	/* Parameter validation */
389 
390 	if (!signature || !out_table) {
391 		return (AE_BAD_PARAMETER);
392 	}
393 
394 	/*
395 	 * Walk the root table list
396 	 */
397 	for (i = 0, j = 0; i < acpi_gbl_root_table_list.count; i++) {
398 		if (!ACPI_COMPARE_NAME
399 		    (&(acpi_gbl_root_table_list.tables[i].signature),
400 		     signature)) {
401 			continue;
402 		}
403 
404 		if (++j < instance) {
405 			continue;
406 		}
407 
408 		status =
409 		    acpi_tb_verify_table(&acpi_gbl_root_table_list.tables[i]);
410 		if (ACPI_SUCCESS(status)) {
411 			*out_table = acpi_gbl_root_table_list.tables[i].pointer;
412 			*tbl_size = acpi_gbl_root_table_list.tables[i].length;
413 		}
414 
415 		if (!acpi_gbl_permanent_mmap) {
416 			acpi_gbl_root_table_list.tables[i].pointer = NULL;
417 		}
418 
419 		return (status);
420 	}
421 
422 	return (AE_NOT_FOUND);
423 }
424 
425 acpi_status
426 acpi_get_table(char *signature,
427 	       u32 instance, struct acpi_table_header **out_table)
428 {
429 	acpi_size tbl_size;
430 
431 	return acpi_get_table_with_size(signature,
432 		       instance, out_table, &tbl_size);
433 }
434 ACPI_EXPORT_SYMBOL(acpi_get_table)
435 
436 /*******************************************************************************
437  *
438  * FUNCTION:    acpi_get_table_by_index
439  *
440  * PARAMETERS:  table_index         - Table index
441  *              Table               - Where the pointer to the table is returned
442  *
443  * RETURN:      Status and pointer to the table
444  *
445  * DESCRIPTION: Obtain a table by an index into the global table list.
446  *
447  ******************************************************************************/
448 acpi_status
449 acpi_get_table_by_index(u32 table_index, struct acpi_table_header **table)
450 {
451 	acpi_status status;
452 
453 	ACPI_FUNCTION_TRACE(acpi_get_table_by_index);
454 
455 	/* Parameter validation */
456 
457 	if (!table) {
458 		return_ACPI_STATUS(AE_BAD_PARAMETER);
459 	}
460 
461 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
462 
463 	/* Validate index */
464 
465 	if (table_index >= acpi_gbl_root_table_list.count) {
466 		(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
467 		return_ACPI_STATUS(AE_BAD_PARAMETER);
468 	}
469 
470 	if (!acpi_gbl_root_table_list.tables[table_index].pointer) {
471 
472 		/* Table is not mapped, map it */
473 
474 		status =
475 		    acpi_tb_verify_table(&acpi_gbl_root_table_list.
476 					 tables[table_index]);
477 		if (ACPI_FAILURE(status)) {
478 			(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
479 			return_ACPI_STATUS(status);
480 		}
481 	}
482 
483 	*table = acpi_gbl_root_table_list.tables[table_index].pointer;
484 	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
485 	return_ACPI_STATUS(AE_OK);
486 }
487 
488 ACPI_EXPORT_SYMBOL(acpi_get_table_by_index)
489 
490 /*******************************************************************************
491  *
492  * FUNCTION:    acpi_tb_load_namespace
493  *
494  * PARAMETERS:  None
495  *
496  * RETURN:      Status
497  *
498  * DESCRIPTION: Load the namespace from the DSDT and all SSDTs/PSDTs found in
499  *              the RSDT/XSDT.
500  *
501  ******************************************************************************/
502 static acpi_status acpi_tb_load_namespace(void)
503 {
504 	acpi_status status;
505 	struct acpi_table_header *table;
506 	u32 i;
507 
508 	ACPI_FUNCTION_TRACE(tb_load_namespace);
509 
510 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
511 
512 	/*
513 	 * Load the namespace. The DSDT is required, but any SSDT and PSDT tables
514 	 * are optional.
515 	 */
516 	if (!acpi_gbl_root_table_list.count ||
517 	    !ACPI_COMPARE_NAME(&
518 			       (acpi_gbl_root_table_list.
519 				tables[ACPI_TABLE_INDEX_DSDT].signature),
520 			       ACPI_SIG_DSDT)
521 	    ||
522 	    ACPI_FAILURE(acpi_tb_verify_table
523 			 (&acpi_gbl_root_table_list.
524 			  tables[ACPI_TABLE_INDEX_DSDT]))) {
525 		status = AE_NO_ACPI_TABLES;
526 		goto unlock_and_exit;
527 	}
528 
529 	/*
530 	 * Find DSDT table
531 	 */
532 	status =
533 	    acpi_os_table_override(acpi_gbl_root_table_list.
534 				   tables[ACPI_TABLE_INDEX_DSDT].pointer,
535 				   &table);
536 	if (ACPI_SUCCESS(status) && table) {
537 		/*
538 		 * DSDT table has been found
539 		 */
540 		acpi_tb_delete_table(&acpi_gbl_root_table_list.
541 				     tables[ACPI_TABLE_INDEX_DSDT]);
542 		acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].pointer =
543 		    table;
544 		acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].length =
545 		    table->length;
546 		acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].flags =
547 		    ACPI_TABLE_ORIGIN_UNKNOWN;
548 
549 		ACPI_INFO((AE_INFO, "Table DSDT replaced by host OS"));
550 		acpi_tb_print_table_header(0, table);
551 
552 		if (no_auto_ssdt == 0) {
553 			printk(KERN_WARNING "ACPI: DSDT override uses original SSDTs unless \"acpi_no_auto_ssdt\"\n");
554 		}
555 	}
556 
557 	status =
558 	    acpi_tb_verify_table(&acpi_gbl_root_table_list.
559 				 tables[ACPI_TABLE_INDEX_DSDT]);
560 	if (ACPI_FAILURE(status)) {
561 
562 		/* A valid DSDT is required */
563 
564 		status = AE_NO_ACPI_TABLES;
565 		goto unlock_and_exit;
566 	}
567 
568 	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
569 
570 	/*
571 	 * Load and parse tables.
572 	 */
573 	status = acpi_ns_load_table(ACPI_TABLE_INDEX_DSDT, acpi_gbl_root_node);
574 	if (ACPI_FAILURE(status)) {
575 		return_ACPI_STATUS(status);
576 	}
577 
578 	/*
579 	 * Load any SSDT or PSDT tables. Note: Loop leaves tables locked
580 	 */
581 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
582 	for (i = 0; i < acpi_gbl_root_table_list.count; ++i) {
583 		if ((!ACPI_COMPARE_NAME
584 		     (&(acpi_gbl_root_table_list.tables[i].signature),
585 		      ACPI_SIG_SSDT)
586 		     &&
587 		     !ACPI_COMPARE_NAME(&
588 					(acpi_gbl_root_table_list.tables[i].
589 					 signature), ACPI_SIG_PSDT))
590 		    ||
591 		    ACPI_FAILURE(acpi_tb_verify_table
592 				 (&acpi_gbl_root_table_list.tables[i]))) {
593 			continue;
594 		}
595 
596 		if (no_auto_ssdt) {
597 			printk(KERN_WARNING "ACPI: SSDT ignored due to \"acpi_no_auto_ssdt\"\n");
598 			continue;
599 		}
600 
601 		/* Ignore errors while loading tables, get as many as possible */
602 
603 		(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
604 		(void)acpi_ns_load_table(i, acpi_gbl_root_node);
605 		(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
606 	}
607 
608 	ACPI_DEBUG_PRINT((ACPI_DB_INIT, "ACPI Tables successfully acquired\n"));
609 
610       unlock_and_exit:
611 	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
612 	return_ACPI_STATUS(status);
613 }
614 
615 /*******************************************************************************
616  *
617  * FUNCTION:    acpi_load_tables
618  *
619  * PARAMETERS:  None
620  *
621  * RETURN:      Status
622  *
623  * DESCRIPTION: Load the ACPI tables from the RSDT/XSDT
624  *
625  ******************************************************************************/
626 
627 acpi_status acpi_load_tables(void)
628 {
629 	acpi_status status;
630 
631 	ACPI_FUNCTION_TRACE(acpi_load_tables);
632 
633 	/*
634 	 * Load the namespace from the tables
635 	 */
636 	status = acpi_tb_load_namespace();
637 	if (ACPI_FAILURE(status)) {
638 		ACPI_EXCEPTION((AE_INFO, status,
639 				"While loading namespace from ACPI tables"));
640 	}
641 
642 	return_ACPI_STATUS(status);
643 }
644 
645 ACPI_EXPORT_SYMBOL(acpi_load_tables)
646 
647 
648 /*******************************************************************************
649  *
650  * FUNCTION:    acpi_install_table_handler
651  *
652  * PARAMETERS:  Handler         - Table event handler
653  *              Context         - Value passed to the handler on each event
654  *
655  * RETURN:      Status
656  *
657  * DESCRIPTION: Install table event handler
658  *
659  ******************************************************************************/
660 acpi_status
661 acpi_install_table_handler(acpi_tbl_handler handler, void *context)
662 {
663 	acpi_status status;
664 
665 	ACPI_FUNCTION_TRACE(acpi_install_table_handler);
666 
667 	if (!handler) {
668 		return_ACPI_STATUS(AE_BAD_PARAMETER);
669 	}
670 
671 	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
672 	if (ACPI_FAILURE(status)) {
673 		return_ACPI_STATUS(status);
674 	}
675 
676 	/* Don't allow more than one handler */
677 
678 	if (acpi_gbl_table_handler) {
679 		status = AE_ALREADY_EXISTS;
680 		goto cleanup;
681 	}
682 
683 	/* Install the handler */
684 
685 	acpi_gbl_table_handler = handler;
686 	acpi_gbl_table_handler_context = context;
687 
688       cleanup:
689 	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
690 	return_ACPI_STATUS(status);
691 }
692 
693 ACPI_EXPORT_SYMBOL(acpi_install_table_handler)
694 
695 /*******************************************************************************
696  *
697  * FUNCTION:    acpi_remove_table_handler
698  *
699  * PARAMETERS:  Handler         - Table event handler that was installed
700  *                                previously.
701  *
702  * RETURN:      Status
703  *
704  * DESCRIPTION: Remove table event handler
705  *
706  ******************************************************************************/
707 acpi_status acpi_remove_table_handler(acpi_tbl_handler handler)
708 {
709 	acpi_status status;
710 
711 	ACPI_FUNCTION_TRACE(acpi_remove_table_handler);
712 
713 	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
714 	if (ACPI_FAILURE(status)) {
715 		return_ACPI_STATUS(status);
716 	}
717 
718 	/* Make sure that the installed handler is the same */
719 
720 	if (!handler || handler != acpi_gbl_table_handler) {
721 		status = AE_BAD_PARAMETER;
722 		goto cleanup;
723 	}
724 
725 	/* Remove the handler */
726 
727 	acpi_gbl_table_handler = NULL;
728 
729       cleanup:
730 	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
731 	return_ACPI_STATUS(status);
732 }
733 
734 ACPI_EXPORT_SYMBOL(acpi_remove_table_handler)
735 
736 
737 static int __init acpi_no_auto_ssdt_setup(char *s) {
738 
739         printk(KERN_NOTICE "ACPI: SSDT auto-load disabled\n");
740 
741         no_auto_ssdt = 1;
742 
743         return 1;
744 }
745 
746 __setup("acpi_no_auto_ssdt", acpi_no_auto_ssdt_setup);
747