[PATCH] cfq-iosched: fix crash in do_div()
[linux-2.6.git] / drivers / acpi / dispatcher / dsmethod.c
1 /******************************************************************************
2  *
3  * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
4  *
5  *****************************************************************************/
6
7 /*
8  * Copyright (C) 2000 - 2006, R. Byron Moore
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 <acpi/acparser.h>
46 #include <acpi/amlcode.h>
47 #include <acpi/acdispat.h>
48 #include <acpi/acinterp.h>
49 #include <acpi/acnamesp.h>
50 #include <acpi/acdisasm.h>
51
52 #define _COMPONENT          ACPI_DISPATCHER
53 ACPI_MODULE_NAME("dsmethod")
54
55 /*******************************************************************************
56  *
57  * FUNCTION:    acpi_ds_method_error
58  *
59  * PARAMETERS:  Status          - Execution status
60  *              walk_state      - Current state
61  *
62  * RETURN:      Status
63  *
64  * DESCRIPTION: Called on method error. Invoke the global exception handler if
65  *              present, dump the method data if the disassembler is configured
66  *
67  *              Note: Allows the exception handler to change the status code
68  *
69  ******************************************************************************/
70 acpi_status
71 acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
72 {
73         ACPI_FUNCTION_ENTRY();
74
75         /* Ignore AE_OK and control exception codes */
76
77         if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
78                 return (status);
79         }
80
81         /* Invoke the global exception handler */
82
83         if (acpi_gbl_exception_handler) {
84                 /* Exit the interpreter, allow handler to execute methods */
85
86                 acpi_ex_exit_interpreter();
87
88                 /*
89                  * Handler can map the exception code to anything it wants, including
90                  * AE_OK, in which case the executing method will not be aborted.
91                  */
92                 status = acpi_gbl_exception_handler(status,
93                                                     walk_state->method_node ?
94                                                     walk_state->method_node->
95                                                     name.integer : 0,
96                                                     walk_state->opcode,
97                                                     walk_state->aml_offset,
98                                                     NULL);
99                 (void)acpi_ex_enter_interpreter();
100         }
101 #ifdef ACPI_DISASSEMBLER
102         if (ACPI_FAILURE(status)) {
103                 /* Display method locals/args if disassembler is present */
104
105                 acpi_dm_dump_method_info(status, walk_state, walk_state->op);
106         }
107 #endif
108
109         return (status);
110 }
111
112 /*******************************************************************************
113  *
114  * FUNCTION:    acpi_ds_begin_method_execution
115  *
116  * PARAMETERS:  method_node         - Node of the method
117  *              obj_desc            - The method object
118  *              calling_method_node - Caller of this method (if non-null)
119  *
120  * RETURN:      Status
121  *
122  * DESCRIPTION: Prepare a method for execution.  Parses the method if necessary,
123  *              increments the thread count, and waits at the method semaphore
124  *              for clearance to execute.
125  *
126  ******************************************************************************/
127
128 acpi_status
129 acpi_ds_begin_method_execution(struct acpi_namespace_node * method_node,
130                                union acpi_operand_object * obj_desc,
131                                struct acpi_namespace_node * calling_method_node)
132 {
133         acpi_status status = AE_OK;
134
135         ACPI_FUNCTION_TRACE_PTR("ds_begin_method_execution", method_node);
136
137         if (!method_node) {
138                 return_ACPI_STATUS(AE_NULL_ENTRY);
139         }
140
141         /* Prevent wraparound of thread count */
142
143         if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
144                 ACPI_ERROR((AE_INFO,
145                             "Method reached maximum reentrancy limit (255)"));
146                 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
147         }
148
149         /*
150          * If there is a concurrency limit on this method, we need to
151          * obtain a unit from the method semaphore.
152          */
153         if (obj_desc->method.semaphore) {
154                 /*
155                  * Allow recursive method calls, up to the reentrancy/concurrency
156                  * limit imposed by the SERIALIZED rule and the sync_level method
157                  * parameter.
158                  *
159                  * The point of this code is to avoid permanently blocking a
160                  * thread that is making recursive method calls.
161                  */
162                 if (method_node == calling_method_node) {
163                         if (obj_desc->method.thread_count >=
164                             obj_desc->method.concurrency) {
165                                 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
166                         }
167                 }
168
169                 /*
170                  * Get a unit from the method semaphore. This releases the
171                  * interpreter if we block
172                  */
173                 status =
174                     acpi_ex_system_wait_semaphore(obj_desc->method.semaphore,
175                                                   ACPI_WAIT_FOREVER);
176         }
177
178         /*
179          * Allocate an Owner ID for this method, only if this is the first thread
180          * to begin concurrent execution. We only need one owner_id, even if the
181          * method is invoked recursively.
182          */
183         if (!obj_desc->method.owner_id) {
184                 status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
185                 if (ACPI_FAILURE(status)) {
186                         return_ACPI_STATUS(status);
187                 }
188         }
189
190         /*
191          * Increment the method parse tree thread count since it has been
192          * reentered one more time (even if it is the same thread)
193          */
194         obj_desc->method.thread_count++;
195         return_ACPI_STATUS(status);
196 }
197
198 /*******************************************************************************
199  *
200  * FUNCTION:    acpi_ds_call_control_method
201  *
202  * PARAMETERS:  Thread              - Info for this thread
203  *              this_walk_state     - Current walk state
204  *              Op                  - Current Op to be walked
205  *
206  * RETURN:      Status
207  *
208  * DESCRIPTION: Transfer execution to a called control method
209  *
210  ******************************************************************************/
211
212 acpi_status
213 acpi_ds_call_control_method(struct acpi_thread_state *thread,
214                             struct acpi_walk_state *this_walk_state,
215                             union acpi_parse_object *op)
216 {
217         acpi_status status;
218         struct acpi_namespace_node *method_node;
219         struct acpi_walk_state *next_walk_state = NULL;
220         union acpi_operand_object *obj_desc;
221         struct acpi_parameter_info info;
222         u32 i;
223
224         ACPI_FUNCTION_TRACE_PTR("ds_call_control_method", this_walk_state);
225
226         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
227                           "Execute method %p, currentstate=%p\n",
228                           this_walk_state->prev_op, this_walk_state));
229
230         /*
231          * Get the namespace entry for the control method we are about to call
232          */
233         method_node = this_walk_state->method_call_node;
234         if (!method_node) {
235                 return_ACPI_STATUS(AE_NULL_ENTRY);
236         }
237
238         obj_desc = acpi_ns_get_attached_object(method_node);
239         if (!obj_desc) {
240                 return_ACPI_STATUS(AE_NULL_OBJECT);
241         }
242
243         /* Init for new method, wait on concurrency semaphore */
244
245         status = acpi_ds_begin_method_execution(method_node, obj_desc,
246                                                 this_walk_state->method_node);
247         if (ACPI_FAILURE(status)) {
248                 goto cleanup;
249         }
250
251         if (!(obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY)) {
252                 /* 1) Parse: Create a new walk state for the preempting walk */
253
254                 next_walk_state =
255                     acpi_ds_create_walk_state(obj_desc->method.owner_id, op,
256                                               obj_desc, NULL);
257                 if (!next_walk_state) {
258                         return_ACPI_STATUS(AE_NO_MEMORY);
259                 }
260
261                 /* Create and init a Root Node */
262
263                 op = acpi_ps_create_scope_op();
264                 if (!op) {
265                         status = AE_NO_MEMORY;
266                         goto cleanup;
267                 }
268
269                 status = acpi_ds_init_aml_walk(next_walk_state, op, method_node,
270                                                obj_desc->method.aml_start,
271                                                obj_desc->method.aml_length,
272                                                NULL, 1);
273                 if (ACPI_FAILURE(status)) {
274                         acpi_ds_delete_walk_state(next_walk_state);
275                         goto cleanup;
276                 }
277
278                 /* Begin AML parse */
279
280                 status = acpi_ps_parse_aml(next_walk_state);
281                 acpi_ps_delete_parse_tree(op);
282         }
283
284         /* 2) Execute: Create a new state for the preempting walk */
285
286         next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
287                                                     NULL, obj_desc, thread);
288         if (!next_walk_state) {
289                 status = AE_NO_MEMORY;
290                 goto cleanup;
291         }
292         /*
293          * The resolved arguments were put on the previous walk state's operand
294          * stack. Operands on the previous walk state stack always
295          * start at index 0. Also, null terminate the list of arguments
296          */
297         this_walk_state->operands[this_walk_state->num_operands] = NULL;
298
299         info.parameters = &this_walk_state->operands[0];
300         info.parameter_type = ACPI_PARAM_ARGS;
301
302         status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
303                                        obj_desc->method.aml_start,
304                                        obj_desc->method.aml_length, &info, 3);
305         if (ACPI_FAILURE(status)) {
306                 goto cleanup;
307         }
308
309         /*
310          * Delete the operands on the previous walkstate operand stack
311          * (they were copied to new objects)
312          */
313         for (i = 0; i < obj_desc->method.param_count; i++) {
314                 acpi_ut_remove_reference(this_walk_state->operands[i]);
315                 this_walk_state->operands[i] = NULL;
316         }
317
318         /* Clear the operand stack */
319
320         this_walk_state->num_operands = 0;
321
322         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
323                           "Starting nested execution, newstate=%p\n",
324                           next_walk_state));
325
326         if (obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY) {
327                 status = obj_desc->method.implementation(next_walk_state);
328         }
329
330         return_ACPI_STATUS(status);
331
332       cleanup:
333         /* Decrement the thread count on the method parse tree */
334
335         if (next_walk_state && (next_walk_state->method_desc)) {
336                 next_walk_state->method_desc->method.thread_count--;
337         }
338
339         /* On error, we must delete the new walk state */
340
341         acpi_ds_terminate_control_method(next_walk_state);
342         acpi_ds_delete_walk_state(next_walk_state);
343         return_ACPI_STATUS(status);
344 }
345
346 /*******************************************************************************
347  *
348  * FUNCTION:    acpi_ds_restart_control_method
349  *
350  * PARAMETERS:  walk_state          - State for preempted method (caller)
351  *              return_desc         - Return value from the called method
352  *
353  * RETURN:      Status
354  *
355  * DESCRIPTION: Restart a method that was preempted by another (nested) method
356  *              invocation.  Handle the return value (if any) from the callee.
357  *
358  ******************************************************************************/
359
360 acpi_status
361 acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
362                                union acpi_operand_object *return_desc)
363 {
364         acpi_status status;
365
366         ACPI_FUNCTION_TRACE_PTR("ds_restart_control_method", walk_state);
367
368         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
369                           "****Restart [%4.4s] Op %p return_value_from_callee %p\n",
370                           (char *)&walk_state->method_node->name,
371                           walk_state->method_call_op, return_desc));
372
373         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
374                           "    return_from_this_method_used?=%X res_stack %p Walk %p\n",
375                           walk_state->return_used,
376                           walk_state->results, walk_state));
377
378         /* Did the called method return a value? */
379
380         if (return_desc) {
381                 /* Are we actually going to use the return value? */
382
383                 if (walk_state->return_used) {
384                         /* Save the return value from the previous method */
385
386                         status = acpi_ds_result_push(return_desc, walk_state);
387                         if (ACPI_FAILURE(status)) {
388                                 acpi_ut_remove_reference(return_desc);
389                                 return_ACPI_STATUS(status);
390                         }
391
392                         /*
393                          * Save as THIS method's return value in case it is returned
394                          * immediately to yet another method
395                          */
396                         walk_state->return_desc = return_desc;
397                 }
398
399                 /*
400                  * The following code is the
401                  * optional support for a so-called "implicit return". Some AML code
402                  * assumes that the last value of the method is "implicitly" returned
403                  * to the caller. Just save the last result as the return value.
404                  * NOTE: this is optional because the ASL language does not actually
405                  * support this behavior.
406                  */
407                 else if (!acpi_ds_do_implicit_return
408                          (return_desc, walk_state, FALSE)) {
409                         /*
410                          * Delete the return value if it will not be used by the
411                          * calling method
412                          */
413                         acpi_ut_remove_reference(return_desc);
414                 }
415         }
416
417         return_ACPI_STATUS(AE_OK);
418 }
419
420 /*******************************************************************************
421  *
422  * FUNCTION:    acpi_ds_terminate_control_method
423  *
424  * PARAMETERS:  walk_state          - State of the method
425  *
426  * RETURN:      None
427  *
428  * DESCRIPTION: Terminate a control method.  Delete everything that the method
429  *              created, delete all locals and arguments, and delete the parse
430  *              tree if requested.
431  *
432  ******************************************************************************/
433
434 void acpi_ds_terminate_control_method(struct acpi_walk_state *walk_state)
435 {
436         union acpi_operand_object *obj_desc;
437         struct acpi_namespace_node *method_node;
438         acpi_status status;
439
440         ACPI_FUNCTION_TRACE_PTR("ds_terminate_control_method", walk_state);
441
442         if (!walk_state) {
443                 return_VOID;
444         }
445
446         /* The current method object was saved in the walk state */
447
448         obj_desc = walk_state->method_desc;
449         if (!obj_desc) {
450                 return_VOID;
451         }
452
453         /* Delete all arguments and locals */
454
455         acpi_ds_method_data_delete_all(walk_state);
456
457         /*
458          * Lock the parser while we terminate this method.
459          * If this is the last thread executing the method,
460          * we have additional cleanup to perform
461          */
462         status = acpi_ut_acquire_mutex(ACPI_MTX_PARSER);
463         if (ACPI_FAILURE(status)) {
464                 return_VOID;
465         }
466
467         /* Signal completion of the execution of this method if necessary */
468
469         if (walk_state->method_desc->method.semaphore) {
470                 status =
471                     acpi_os_signal_semaphore(walk_state->method_desc->method.
472                                              semaphore, 1);
473                 if (ACPI_FAILURE(status)) {
474                         ACPI_ERROR((AE_INFO,
475                                     "Could not signal method semaphore"));
476
477                         /* Ignore error and continue cleanup */
478                 }
479         }
480
481         /*
482          * There are no more threads executing this method.  Perform
483          * additional cleanup.
484          *
485          * The method Node is stored in the walk state
486          */
487         method_node = walk_state->method_node;
488
489         /* Lock namespace for possible update */
490
491         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
492         if (ACPI_FAILURE(status)) {
493                 goto exit;
494         }
495
496         /*
497          * Delete any namespace entries created immediately underneath
498          * the method
499          */
500         if (method_node->child) {
501                 acpi_ns_delete_namespace_subtree(method_node);
502         }
503
504         /*
505          * Delete any namespace entries created anywhere else within
506          * the namespace by the execution of this method
507          */
508         acpi_ns_delete_namespace_by_owner(walk_state->method_desc->method.
509                                           owner_id);
510         status = acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
511
512         /* Are there any other threads currently executing this method? */
513
514         if (walk_state->method_desc->method.thread_count) {
515                 /*
516                  * Additional threads. Do not release the owner_id in this case,
517                  * we immediately reuse it for the next thread executing this method
518                  */
519                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
520                                   "*** Completed execution of one thread, %d threads remaining\n",
521                                   walk_state->method_desc->method.
522                                   thread_count));
523         } else {
524                 /* This is the only executing thread for this method */
525
526                 /*
527                  * Support to dynamically change a method from not_serialized to
528                  * Serialized if it appears that the method is incorrectly written and
529                  * does not support multiple thread execution.  The best example of this
530                  * is if such a method creates namespace objects and blocks.  A second
531                  * thread will fail with an AE_ALREADY_EXISTS exception
532                  *
533                  * This code is here because we must wait until the last thread exits
534                  * before creating the synchronization semaphore.
535                  */
536                 if ((walk_state->method_desc->method.concurrency == 1) &&
537                     (!walk_state->method_desc->method.semaphore)) {
538                         status = acpi_os_create_semaphore(1, 1,
539                                                           &walk_state->
540                                                           method_desc->method.
541                                                           semaphore);
542                 }
543
544                 /* No more threads, we can free the owner_id */
545
546                 acpi_ut_release_owner_id(&walk_state->method_desc->method.
547                                          owner_id);
548         }
549
550       exit:
551         (void)acpi_ut_release_mutex(ACPI_MTX_PARSER);
552         return_VOID;
553 }
554
555 #ifdef ACPI_INIT_PARSE_METHODS
556         /*
557          * Note 11/2005: Removed this code to parse all methods during table
558          * load because it causes problems if there are any errors during the
559          * parse. Also, it seems like overkill and we probably don't want to
560          * abort a table load because of an issue with a single method.
561          */
562
563 /*******************************************************************************
564  *
565  * FUNCTION:    acpi_ds_parse_method
566  *
567  * PARAMETERS:  Node        - Method node
568  *
569  * RETURN:      Status
570  *
571  * DESCRIPTION: Parse the AML that is associated with the method.
572  *
573  * MUTEX:       Assumes parser is locked
574  *
575  ******************************************************************************/
576
577 acpi_status acpi_ds_parse_method(struct acpi_namespace_node *node)
578 {
579         acpi_status status;
580         union acpi_operand_object *obj_desc;
581         union acpi_parse_object *op;
582         struct acpi_walk_state *walk_state;
583
584         ACPI_FUNCTION_TRACE_PTR("ds_parse_method", node);
585
586         /* Parameter Validation */
587
588         if (!node) {
589                 return_ACPI_STATUS(AE_NULL_ENTRY);
590         }
591
592         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
593                           "**** Parsing [%4.4s] **** named_obj=%p\n",
594                           acpi_ut_get_node_name(node), node));
595
596         /* Extract the method object from the method Node */
597
598         obj_desc = acpi_ns_get_attached_object(node);
599         if (!obj_desc) {
600                 return_ACPI_STATUS(AE_NULL_OBJECT);
601         }
602
603         /* Create a mutex for the method if there is a concurrency limit */
604
605         if ((obj_desc->method.concurrency != ACPI_INFINITE_CONCURRENCY) &&
606             (!obj_desc->method.semaphore)) {
607                 status = acpi_os_create_semaphore(obj_desc->method.concurrency,
608                                                   obj_desc->method.concurrency,
609                                                   &obj_desc->method.semaphore);
610                 if (ACPI_FAILURE(status)) {
611                         return_ACPI_STATUS(status);
612                 }
613         }
614
615         /*
616          * Allocate a new parser op to be the root of the parsed
617          * method tree
618          */
619         op = acpi_ps_alloc_op(AML_METHOD_OP);
620         if (!op) {
621                 return_ACPI_STATUS(AE_NO_MEMORY);
622         }
623
624         /* Init new op with the method name and pointer back to the Node */
625
626         acpi_ps_set_name(op, node->name.integer);
627         op->common.node = node;
628
629         /*
630          * Get a new owner_id for objects created by this method. Namespace
631          * objects (such as Operation Regions) can be created during the
632          * first pass parse.
633          */
634         status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
635         if (ACPI_FAILURE(status)) {
636                 goto cleanup;
637         }
638
639         /* Create and initialize a new walk state */
640
641         walk_state =
642             acpi_ds_create_walk_state(obj_desc->method.owner_id, NULL, NULL,
643                                       NULL);
644         if (!walk_state) {
645                 status = AE_NO_MEMORY;
646                 goto cleanup2;
647         }
648
649         status = acpi_ds_init_aml_walk(walk_state, op, node,
650                                        obj_desc->method.aml_start,
651                                        obj_desc->method.aml_length, NULL, 1);
652         if (ACPI_FAILURE(status)) {
653                 acpi_ds_delete_walk_state(walk_state);
654                 goto cleanup2;
655         }
656
657         /*
658          * Parse the method, first pass
659          *
660          * The first pass load is where newly declared named objects are added into
661          * the namespace.  Actual evaluation of the named objects (what would be
662          * called a "second pass") happens during the actual execution of the
663          * method so that operands to the named objects can take on dynamic
664          * run-time values.
665          */
666         status = acpi_ps_parse_aml(walk_state);
667         if (ACPI_FAILURE(status)) {
668                 goto cleanup2;
669         }
670
671         ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
672                           "**** [%4.4s] Parsed **** named_obj=%p Op=%p\n",
673                           acpi_ut_get_node_name(node), node, op));
674
675         /*
676          * Delete the parse tree. We simply re-parse the method for every
677          * execution since there isn't much overhead (compared to keeping lots
678          * of parse trees around)
679          */
680         acpi_ns_delete_namespace_subtree(node);
681         acpi_ns_delete_namespace_by_owner(obj_desc->method.owner_id);
682
683       cleanup2:
684         acpi_ut_release_owner_id(&obj_desc->method.owner_id);
685
686       cleanup:
687         acpi_ps_delete_parse_tree(op);
688         return_ACPI_STATUS(status);
689 }
690 #endif