xref: /openbmc/linux/drivers/acpi/acpica/tbxface.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
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 - 2010, 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.max_table_count = 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.max_table_count = 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 = acpi_tb_parse_root_table(rsdp_address);
154 	return_ACPI_STATUS(status);
155 }
156 
157 /*******************************************************************************
158  *
159  * FUNCTION:    acpi_reallocate_root_table
160  *
161  * PARAMETERS:  None
162  *
163  * RETURN:      Status
164  *
165  * DESCRIPTION: Reallocate Root Table List into dynamic memory. Copies the
166  *              root list from the previously provided scratch area. Should
167  *              be called once dynamic memory allocation is available in the
168  *              kernel
169  *
170  ******************************************************************************/
171 acpi_status acpi_reallocate_root_table(void)
172 {
173 	struct acpi_table_desc *tables;
174 	acpi_size new_size;
175 	acpi_size current_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 	/*
188 	 * Get the current size of the root table and add the default
189 	 * increment to create the new table size.
190 	 */
191 	current_size = (acpi_size)
192 	    acpi_gbl_root_table_list.current_table_count *
193 	    sizeof(struct acpi_table_desc);
194 
195 	new_size = current_size +
196 	    (ACPI_ROOT_TABLE_SIZE_INCREMENT * sizeof(struct acpi_table_desc));
197 
198 	/* Create new array and copy the old array */
199 
200 	tables = ACPI_ALLOCATE_ZEROED(new_size);
201 	if (!tables) {
202 		return_ACPI_STATUS(AE_NO_MEMORY);
203 	}
204 
205 	ACPI_MEMCPY(tables, acpi_gbl_root_table_list.tables, current_size);
206 
207 	/*
208 	 * Update the root table descriptor. The new size will be the current
209 	 * number of tables plus the increment, independent of the reserved
210 	 * size of the original table list.
211 	 */
212 	acpi_gbl_root_table_list.tables = tables;
213 	acpi_gbl_root_table_list.max_table_count =
214 	    acpi_gbl_root_table_list.current_table_count +
215 	    ACPI_ROOT_TABLE_SIZE_INCREMENT;
216 	acpi_gbl_root_table_list.flags =
217 	    ACPI_ROOT_ORIGIN_ALLOCATED | ACPI_ROOT_ALLOW_RESIZE;
218 
219 	return_ACPI_STATUS(AE_OK);
220 }
221 
222 /*******************************************************************************
223  *
224  * FUNCTION:    acpi_load_table
225  *
226  * PARAMETERS:  table_ptr       - pointer to a buffer containing the entire
227  *                                table to be loaded
228  *
229  * RETURN:      Status
230  *
231  * DESCRIPTION: This function is called to load a table from the caller's
232  *              buffer. The buffer must contain an entire ACPI Table including
233  *              a valid header. The header fields will be verified, and if it
234  *              is determined that the table is invalid, the call will fail.
235  *
236  ******************************************************************************/
237 acpi_status acpi_load_table(struct acpi_table_header *table_ptr)
238 {
239 	acpi_status status;
240 	u32 table_index;
241 	struct acpi_table_desc table_desc;
242 
243 	if (!table_ptr)
244 		return AE_BAD_PARAMETER;
245 
246 	ACPI_MEMSET(&table_desc, 0, sizeof(struct acpi_table_desc));
247 	table_desc.pointer = table_ptr;
248 	table_desc.length = table_ptr->length;
249 	table_desc.flags = ACPI_TABLE_ORIGIN_UNKNOWN;
250 
251 	/*
252 	 * Install the new table into the local data structures
253 	 */
254 	status = acpi_tb_add_table(&table_desc, &table_index);
255 	if (ACPI_FAILURE(status)) {
256 		return status;
257 	}
258 	status = acpi_ns_load_table(table_index, acpi_gbl_root_node);
259 	return status;
260 }
261 
262 ACPI_EXPORT_SYMBOL(acpi_load_table)
263 
264 /*******************************************************************************
265  *
266  * FUNCTION:    acpi_get_table_header
267  *
268  * PARAMETERS:  Signature           - ACPI signature of needed table
269  *              Instance            - Which instance (for SSDTs)
270  *              out_table_header    - The pointer to the table header to fill
271  *
272  * RETURN:      Status and pointer to mapped table header
273  *
274  * DESCRIPTION: Finds an ACPI table header.
275  *
276  * NOTE:        Caller is responsible in unmapping the header with
277  *              acpi_os_unmap_memory
278  *
279  ******************************************************************************/
280 acpi_status
281 acpi_get_table_header(char *signature,
282 		      u32 instance, struct acpi_table_header *out_table_header)
283 {
284        u32 i;
285        u32 j;
286 	struct acpi_table_header *header;
287 
288 	/* Parameter validation */
289 
290 	if (!signature || !out_table_header) {
291 		return (AE_BAD_PARAMETER);
292 	}
293 
294 	/* Walk the root table list */
295 
296 	for (i = 0, j = 0; i < acpi_gbl_root_table_list.current_table_count;
297 	     i++) {
298 		if (!ACPI_COMPARE_NAME
299 		    (&(acpi_gbl_root_table_list.tables[i].signature),
300 		     signature)) {
301 			continue;
302 		}
303 
304 		if (++j < instance) {
305 			continue;
306 		}
307 
308 		if (!acpi_gbl_root_table_list.tables[i].pointer) {
309 			if ((acpi_gbl_root_table_list.tables[i].flags &
310 			     ACPI_TABLE_ORIGIN_MASK) ==
311 			    ACPI_TABLE_ORIGIN_MAPPED) {
312 				header =
313 				    acpi_os_map_memory(acpi_gbl_root_table_list.
314 						       tables[i].address,
315 						       sizeof(struct
316 							      acpi_table_header));
317 				if (!header) {
318 					return AE_NO_MEMORY;
319 				}
320 				ACPI_MEMCPY(out_table_header, header,
321 					    sizeof(struct acpi_table_header));
322 				acpi_os_unmap_memory(header,
323 						     sizeof(struct
324 							    acpi_table_header));
325 			} else {
326 				return AE_NOT_FOUND;
327 			}
328 		} else {
329 			ACPI_MEMCPY(out_table_header,
330 				    acpi_gbl_root_table_list.tables[i].pointer,
331 				    sizeof(struct acpi_table_header));
332 		}
333 		return (AE_OK);
334 	}
335 
336 	return (AE_NOT_FOUND);
337 }
338 
339 ACPI_EXPORT_SYMBOL(acpi_get_table_header)
340 
341 /*******************************************************************************
342  *
343  * FUNCTION:    acpi_unload_table_id
344  *
345  * PARAMETERS:  id            - Owner ID of the table to be removed.
346  *
347  * RETURN:      Status
348  *
349  * DESCRIPTION: This routine is used to force the unload of a table (by id)
350  *
351  ******************************************************************************/
352 acpi_status acpi_unload_table_id(acpi_owner_id id)
353 {
354 	int i;
355 	acpi_status status = AE_NOT_EXIST;
356 
357 	ACPI_FUNCTION_TRACE(acpi_unload_table_id);
358 
359 	/* Find table in the global table list */
360 	for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
361 		if (id != acpi_gbl_root_table_list.tables[i].owner_id) {
362 			continue;
363 		}
364 		/*
365 		 * Delete all namespace objects owned by this table. Note that these
366 		 * objects can appear anywhere in the namespace by virtue of the AML
367 		 * "Scope" operator. Thus, we need to track ownership by an ID, not
368 		 * simply a position within the hierarchy
369 		 */
370 		acpi_tb_delete_namespace_by_owner(i);
371 		status = acpi_tb_release_owner_id(i);
372 		acpi_tb_set_table_loaded_flag(i, FALSE);
373 		break;
374 	}
375 	return_ACPI_STATUS(status);
376 }
377 
378 ACPI_EXPORT_SYMBOL(acpi_unload_table_id)
379 
380 /*******************************************************************************
381  *
382  * FUNCTION:    acpi_get_table_with_size
383  *
384  * PARAMETERS:  Signature           - ACPI signature of needed table
385  *              Instance            - Which instance (for SSDTs)
386  *              out_table           - Where the pointer to the table is returned
387  *
388  * RETURN:      Status and pointer to table
389  *
390  * DESCRIPTION: Finds and verifies an ACPI table.
391  *
392  ******************************************************************************/
393 acpi_status
394 acpi_get_table_with_size(char *signature,
395 	       u32 instance, struct acpi_table_header **out_table,
396 	       acpi_size *tbl_size)
397 {
398        u32 i;
399        u32 j;
400 	acpi_status status;
401 
402 	/* Parameter validation */
403 
404 	if (!signature || !out_table) {
405 		return (AE_BAD_PARAMETER);
406 	}
407 
408 	/* Walk the root table list */
409 
410 	for (i = 0, j = 0; i < acpi_gbl_root_table_list.current_table_count;
411 	     i++) {
412 		if (!ACPI_COMPARE_NAME
413 		    (&(acpi_gbl_root_table_list.tables[i].signature),
414 		     signature)) {
415 			continue;
416 		}
417 
418 		if (++j < instance) {
419 			continue;
420 		}
421 
422 		status =
423 		    acpi_tb_verify_table(&acpi_gbl_root_table_list.tables[i]);
424 		if (ACPI_SUCCESS(status)) {
425 			*out_table = acpi_gbl_root_table_list.tables[i].pointer;
426 			*tbl_size = acpi_gbl_root_table_list.tables[i].length;
427 		}
428 
429 		if (!acpi_gbl_permanent_mmap) {
430 			acpi_gbl_root_table_list.tables[i].pointer = NULL;
431 		}
432 
433 		return (status);
434 	}
435 
436 	return (AE_NOT_FOUND);
437 }
438 
439 acpi_status
440 acpi_get_table(char *signature,
441 	       u32 instance, struct acpi_table_header **out_table)
442 {
443 	acpi_size tbl_size;
444 
445 	return acpi_get_table_with_size(signature,
446 		       instance, out_table, &tbl_size);
447 }
448 ACPI_EXPORT_SYMBOL(acpi_get_table)
449 
450 /*******************************************************************************
451  *
452  * FUNCTION:    acpi_get_table_by_index
453  *
454  * PARAMETERS:  table_index         - Table index
455  *              Table               - Where the pointer to the table is returned
456  *
457  * RETURN:      Status and pointer to the table
458  *
459  * DESCRIPTION: Obtain a table by an index into the global table list.
460  *
461  ******************************************************************************/
462 acpi_status
463 acpi_get_table_by_index(u32 table_index, struct acpi_table_header **table)
464 {
465 	acpi_status status;
466 
467 	ACPI_FUNCTION_TRACE(acpi_get_table_by_index);
468 
469 	/* Parameter validation */
470 
471 	if (!table) {
472 		return_ACPI_STATUS(AE_BAD_PARAMETER);
473 	}
474 
475 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
476 
477 	/* Validate index */
478 
479 	if (table_index >= acpi_gbl_root_table_list.current_table_count) {
480 		(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
481 		return_ACPI_STATUS(AE_BAD_PARAMETER);
482 	}
483 
484 	if (!acpi_gbl_root_table_list.tables[table_index].pointer) {
485 
486 		/* Table is not mapped, map it */
487 
488 		status =
489 		    acpi_tb_verify_table(&acpi_gbl_root_table_list.
490 					 tables[table_index]);
491 		if (ACPI_FAILURE(status)) {
492 			(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
493 			return_ACPI_STATUS(status);
494 		}
495 	}
496 
497 	*table = acpi_gbl_root_table_list.tables[table_index].pointer;
498 	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
499 	return_ACPI_STATUS(AE_OK);
500 }
501 
502 ACPI_EXPORT_SYMBOL(acpi_get_table_by_index)
503 
504 /*******************************************************************************
505  *
506  * FUNCTION:    acpi_tb_load_namespace
507  *
508  * PARAMETERS:  None
509  *
510  * RETURN:      Status
511  *
512  * DESCRIPTION: Load the namespace from the DSDT and all SSDTs/PSDTs found in
513  *              the RSDT/XSDT.
514  *
515  ******************************************************************************/
516 static acpi_status acpi_tb_load_namespace(void)
517 {
518 	acpi_status status;
519 	u32 i;
520 	struct acpi_table_header *new_dsdt;
521 
522 	ACPI_FUNCTION_TRACE(tb_load_namespace);
523 
524 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
525 
526 	/*
527 	 * Load the namespace. The DSDT is required, but any SSDT and
528 	 * PSDT tables are optional. Verify the DSDT.
529 	 */
530 	if (!acpi_gbl_root_table_list.current_table_count ||
531 	    !ACPI_COMPARE_NAME(&
532 			       (acpi_gbl_root_table_list.
533 				tables[ACPI_TABLE_INDEX_DSDT].signature),
534 			       ACPI_SIG_DSDT)
535 	    ||
536 	    ACPI_FAILURE(acpi_tb_verify_table
537 			 (&acpi_gbl_root_table_list.
538 			  tables[ACPI_TABLE_INDEX_DSDT]))) {
539 		status = AE_NO_ACPI_TABLES;
540 		goto unlock_and_exit;
541 	}
542 
543 	/*
544 	 * Save the DSDT pointer for simple access. This is the mapped memory
545 	 * address. We must take care here because the address of the .Tables
546 	 * array can change dynamically as tables are loaded at run-time. Note:
547 	 * .Pointer field is not validated until after call to acpi_tb_verify_table.
548 	 */
549 	acpi_gbl_DSDT =
550 	    acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].pointer;
551 
552 	/*
553 	 * Optionally copy the entire DSDT to local memory (instead of simply
554 	 * mapping it.) There are some BIOSs that corrupt or replace the original
555 	 * DSDT, creating the need for this option. Default is FALSE, do not copy
556 	 * the DSDT.
557 	 */
558 	if (acpi_gbl_copy_dsdt_locally) {
559 		new_dsdt = acpi_tb_copy_dsdt(ACPI_TABLE_INDEX_DSDT);
560 		if (new_dsdt) {
561 			acpi_gbl_DSDT = new_dsdt;
562 		}
563 	}
564 
565 	/*
566 	 * Save the original DSDT header for detection of table corruption
567 	 * and/or replacement of the DSDT from outside the OS.
568 	 */
569 	ACPI_MEMCPY(&acpi_gbl_original_dsdt_header, acpi_gbl_DSDT,
570 		    sizeof(struct acpi_table_header));
571 
572 	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
573 
574 	/* Load and parse tables */
575 
576 	status = acpi_ns_load_table(ACPI_TABLE_INDEX_DSDT, acpi_gbl_root_node);
577 	if (ACPI_FAILURE(status)) {
578 		return_ACPI_STATUS(status);
579 	}
580 
581 	/* Load any SSDT or PSDT tables. Note: Loop leaves tables locked */
582 
583 	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
584 	for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
585 		if ((!ACPI_COMPARE_NAME
586 		     (&(acpi_gbl_root_table_list.tables[i].signature),
587 		      ACPI_SIG_SSDT)
588 		     &&
589 		     !ACPI_COMPARE_NAME(&
590 					(acpi_gbl_root_table_list.tables[i].
591 					 signature), ACPI_SIG_PSDT))
592 		    ||
593 		    ACPI_FAILURE(acpi_tb_verify_table
594 				 (&acpi_gbl_root_table_list.tables[i]))) {
595 			continue;
596 		}
597 
598 		if (no_auto_ssdt) {
599 			printk(KERN_WARNING "ACPI: SSDT ignored due to \"acpi_no_auto_ssdt\"\n");
600 			continue;
601 		}
602 
603 		/* Ignore errors while loading tables, get as many as possible */
604 
605 		(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
606 		(void)acpi_ns_load_table(i, acpi_gbl_root_node);
607 		(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
608 	}
609 
610 	ACPI_DEBUG_PRINT((ACPI_DB_INIT, "ACPI Tables successfully acquired\n"));
611 
612       unlock_and_exit:
613 	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
614 	return_ACPI_STATUS(status);
615 }
616 
617 /*******************************************************************************
618  *
619  * FUNCTION:    acpi_load_tables
620  *
621  * PARAMETERS:  None
622  *
623  * RETURN:      Status
624  *
625  * DESCRIPTION: Load the ACPI tables from the RSDT/XSDT
626  *
627  ******************************************************************************/
628 
629 acpi_status acpi_load_tables(void)
630 {
631 	acpi_status status;
632 
633 	ACPI_FUNCTION_TRACE(acpi_load_tables);
634 
635 	/* Load the namespace from the tables */
636 
637 	status = acpi_tb_load_namespace();
638 	if (ACPI_FAILURE(status)) {
639 		ACPI_EXCEPTION((AE_INFO, status,
640 				"While loading namespace from ACPI tables"));
641 	}
642 
643 	return_ACPI_STATUS(status);
644 }
645 
646 ACPI_EXPORT_SYMBOL(acpi_load_tables)
647 
648 
649 /*******************************************************************************
650  *
651  * FUNCTION:    acpi_install_table_handler
652  *
653  * PARAMETERS:  Handler         - Table event handler
654  *              Context         - Value passed to the handler on each event
655  *
656  * RETURN:      Status
657  *
658  * DESCRIPTION: Install table event handler
659  *
660  ******************************************************************************/
661 acpi_status
662 acpi_install_table_handler(acpi_tbl_handler handler, void *context)
663 {
664 	acpi_status status;
665 
666 	ACPI_FUNCTION_TRACE(acpi_install_table_handler);
667 
668 	if (!handler) {
669 		return_ACPI_STATUS(AE_BAD_PARAMETER);
670 	}
671 
672 	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
673 	if (ACPI_FAILURE(status)) {
674 		return_ACPI_STATUS(status);
675 	}
676 
677 	/* Don't allow more than one handler */
678 
679 	if (acpi_gbl_table_handler) {
680 		status = AE_ALREADY_EXISTS;
681 		goto cleanup;
682 	}
683 
684 	/* Install the handler */
685 
686 	acpi_gbl_table_handler = handler;
687 	acpi_gbl_table_handler_context = context;
688 
689       cleanup:
690 	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
691 	return_ACPI_STATUS(status);
692 }
693 
694 ACPI_EXPORT_SYMBOL(acpi_install_table_handler)
695 
696 /*******************************************************************************
697  *
698  * FUNCTION:    acpi_remove_table_handler
699  *
700  * PARAMETERS:  Handler         - Table event handler that was installed
701  *                                previously.
702  *
703  * RETURN:      Status
704  *
705  * DESCRIPTION: Remove table event handler
706  *
707  ******************************************************************************/
708 acpi_status acpi_remove_table_handler(acpi_tbl_handler handler)
709 {
710 	acpi_status status;
711 
712 	ACPI_FUNCTION_TRACE(acpi_remove_table_handler);
713 
714 	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
715 	if (ACPI_FAILURE(status)) {
716 		return_ACPI_STATUS(status);
717 	}
718 
719 	/* Make sure that the installed handler is the same */
720 
721 	if (!handler || handler != acpi_gbl_table_handler) {
722 		status = AE_BAD_PARAMETER;
723 		goto cleanup;
724 	}
725 
726 	/* Remove the handler */
727 
728 	acpi_gbl_table_handler = NULL;
729 
730       cleanup:
731 	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
732 	return_ACPI_STATUS(status);
733 }
734 
735 ACPI_EXPORT_SYMBOL(acpi_remove_table_handler)
736 
737 
738 static int __init acpi_no_auto_ssdt_setup(char *s) {
739 
740         printk(KERN_NOTICE "ACPI: SSDT auto-load disabled\n");
741 
742         no_auto_ssdt = 1;
743 
744         return 1;
745 }
746 
747 __setup("acpi_no_auto_ssdt", acpi_no_auto_ssdt_setup);
748