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1 | /****************************************************************************** |
2 | * | |
3 | * Module Name: dscontrol - Support for execution control opcodes - | |
4 | * if/else/while/return | |
5 | * | |
6 | *****************************************************************************/ | |
7 | ||
8 | /* | |
9 | * Copyright (C) 2000 - 2011, 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 "amlcode.h" | |
48 | #include "acdispat.h" | |
49 | #include "acinterp.h" | |
50 | ||
51 | #define _COMPONENT ACPI_DISPATCHER | |
52 | ACPI_MODULE_NAME("dscontrol") | |
53 | ||
54 | /******************************************************************************* | |
55 | * | |
56 | * FUNCTION: acpi_ds_exec_begin_control_op | |
57 | * | |
58 | * PARAMETERS: walk_list - The list that owns the walk stack | |
59 | * Op - The control Op | |
60 | * | |
61 | * RETURN: Status | |
62 | * | |
63 | * DESCRIPTION: Handles all control ops encountered during control method | |
64 | * execution. | |
65 | * | |
66 | ******************************************************************************/ | |
67 | acpi_status | |
68 | acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state, | |
69 | union acpi_parse_object *op) | |
70 | { | |
71 | acpi_status status = AE_OK; | |
72 | union acpi_generic_state *control_state; | |
73 | ||
74 | ACPI_FUNCTION_NAME(ds_exec_begin_control_op); | |
75 | ||
76 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n", | |
77 | op, op->common.aml_opcode, walk_state)); | |
78 | ||
79 | switch (op->common.aml_opcode) { | |
80 | case AML_WHILE_OP: | |
81 | ||
82 | /* | |
83 | * If this is an additional iteration of a while loop, continue. | |
84 | * There is no need to allocate a new control state. | |
85 | */ | |
86 | if (walk_state->control_state) { | |
87 | if (walk_state->control_state->control. | |
88 | aml_predicate_start == | |
89 | (walk_state->parser_state.aml - 1)) { | |
90 | ||
91 | /* Reset the state to start-of-loop */ | |
92 | ||
93 | walk_state->control_state->common.state = | |
94 | ACPI_CONTROL_CONDITIONAL_EXECUTING; | |
95 | break; | |
96 | } | |
97 | } | |
98 | ||
99 | /*lint -fallthrough */ | |
100 | ||
101 | case AML_IF_OP: | |
102 | ||
103 | /* | |
104 | * IF/WHILE: Create a new control state to manage these | |
105 | * constructs. We need to manage these as a stack, in order | |
106 | * to handle nesting. | |
107 | */ | |
108 | control_state = acpi_ut_create_control_state(); | |
109 | if (!control_state) { | |
110 | status = AE_NO_MEMORY; | |
111 | break; | |
112 | } | |
113 | /* | |
114 | * Save a pointer to the predicate for multiple executions | |
115 | * of a loop | |
116 | */ | |
117 | control_state->control.aml_predicate_start = | |
118 | walk_state->parser_state.aml - 1; | |
119 | control_state->control.package_end = | |
120 | walk_state->parser_state.pkg_end; | |
121 | control_state->control.opcode = op->common.aml_opcode; | |
122 | ||
123 | /* Push the control state on this walk's control stack */ | |
124 | ||
125 | acpi_ut_push_generic_state(&walk_state->control_state, | |
126 | control_state); | |
127 | break; | |
128 | ||
129 | case AML_ELSE_OP: | |
130 | ||
131 | /* Predicate is in the state object */ | |
132 | /* If predicate is true, the IF was executed, ignore ELSE part */ | |
133 | ||
134 | if (walk_state->last_predicate) { | |
135 | status = AE_CTRL_TRUE; | |
136 | } | |
137 | ||
138 | break; | |
139 | ||
140 | case AML_RETURN_OP: | |
141 | ||
142 | break; | |
143 | ||
144 | default: | |
145 | break; | |
146 | } | |
147 | ||
148 | return (status); | |
149 | } | |
150 | ||
151 | /******************************************************************************* | |
152 | * | |
153 | * FUNCTION: acpi_ds_exec_end_control_op | |
154 | * | |
155 | * PARAMETERS: walk_list - The list that owns the walk stack | |
156 | * Op - The control Op | |
157 | * | |
158 | * RETURN: Status | |
159 | * | |
160 | * DESCRIPTION: Handles all control ops encountered during control method | |
161 | * execution. | |
162 | * | |
163 | ******************************************************************************/ | |
164 | ||
165 | acpi_status | |
166 | acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state, | |
167 | union acpi_parse_object * op) | |
168 | { | |
169 | acpi_status status = AE_OK; | |
170 | union acpi_generic_state *control_state; | |
171 | ||
172 | ACPI_FUNCTION_NAME(ds_exec_end_control_op); | |
173 | ||
174 | switch (op->common.aml_opcode) { | |
175 | case AML_IF_OP: | |
176 | ||
177 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op)); | |
178 | ||
179 | /* | |
180 | * Save the result of the predicate in case there is an | |
181 | * ELSE to come | |
182 | */ | |
183 | walk_state->last_predicate = | |
184 | (u8)walk_state->control_state->common.value; | |
185 | ||
186 | /* | |
187 | * Pop the control state that was created at the start | |
188 | * of the IF and free it | |
189 | */ | |
190 | control_state = | |
191 | acpi_ut_pop_generic_state(&walk_state->control_state); | |
192 | acpi_ut_delete_generic_state(control_state); | |
193 | break; | |
194 | ||
195 | case AML_ELSE_OP: | |
196 | ||
197 | break; | |
198 | ||
199 | case AML_WHILE_OP: | |
200 | ||
201 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op)); | |
202 | ||
203 | control_state = walk_state->control_state; | |
204 | if (control_state->common.value) { | |
205 | ||
206 | /* Predicate was true, the body of the loop was just executed */ | |
207 | ||
208 | /* | |
209 | * This loop counter mechanism allows the interpreter to escape | |
210 | * possibly infinite loops. This can occur in poorly written AML | |
211 | * when the hardware does not respond within a while loop and the | |
212 | * loop does not implement a timeout. | |
213 | */ | |
214 | control_state->control.loop_count++; | |
215 | if (control_state->control.loop_count > | |
216 | ACPI_MAX_LOOP_ITERATIONS) { | |
217 | status = AE_AML_INFINITE_LOOP; | |
218 | break; | |
219 | } | |
220 | ||
221 | /* | |
222 | * Go back and evaluate the predicate and maybe execute the loop | |
223 | * another time | |
224 | */ | |
225 | status = AE_CTRL_PENDING; | |
226 | walk_state->aml_last_while = | |
227 | control_state->control.aml_predicate_start; | |
228 | break; | |
229 | } | |
230 | ||
231 | /* Predicate was false, terminate this while loop */ | |
232 | ||
233 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, | |
234 | "[WHILE_OP] termination! Op=%p\n", op)); | |
235 | ||
236 | /* Pop this control state and free it */ | |
237 | ||
238 | control_state = | |
239 | acpi_ut_pop_generic_state(&walk_state->control_state); | |
240 | acpi_ut_delete_generic_state(control_state); | |
241 | break; | |
242 | ||
243 | case AML_RETURN_OP: | |
244 | ||
245 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, | |
246 | "[RETURN_OP] Op=%p Arg=%p\n", op, | |
247 | op->common.value.arg)); | |
248 | ||
249 | /* | |
250 | * One optional operand -- the return value | |
251 | * It can be either an immediate operand or a result that | |
252 | * has been bubbled up the tree | |
253 | */ | |
254 | if (op->common.value.arg) { | |
255 | ||
256 | /* Since we have a real Return(), delete any implicit return */ | |
257 | ||
258 | acpi_ds_clear_implicit_return(walk_state); | |
259 | ||
260 | /* Return statement has an immediate operand */ | |
261 | ||
262 | status = | |
263 | acpi_ds_create_operands(walk_state, | |
264 | op->common.value.arg); | |
265 | if (ACPI_FAILURE(status)) { | |
266 | return (status); | |
267 | } | |
268 | ||
269 | /* | |
270 | * If value being returned is a Reference (such as | |
271 | * an arg or local), resolve it now because it may | |
272 | * cease to exist at the end of the method. | |
273 | */ | |
274 | status = | |
275 | acpi_ex_resolve_to_value(&walk_state->operands[0], | |
276 | walk_state); | |
277 | if (ACPI_FAILURE(status)) { | |
278 | return (status); | |
279 | } | |
280 | ||
281 | /* | |
282 | * Get the return value and save as the last result | |
283 | * value. This is the only place where walk_state->return_desc | |
284 | * is set to anything other than zero! | |
285 | */ | |
286 | walk_state->return_desc = walk_state->operands[0]; | |
287 | } else if (walk_state->result_count) { | |
288 | ||
289 | /* Since we have a real Return(), delete any implicit return */ | |
290 | ||
291 | acpi_ds_clear_implicit_return(walk_state); | |
292 | ||
293 | /* | |
294 | * The return value has come from a previous calculation. | |
295 | * | |
296 | * If value being returned is a Reference (such as | |
297 | * an arg or local), resolve it now because it may | |
298 | * cease to exist at the end of the method. | |
299 | * | |
300 | * Allow references created by the Index operator to return | |
301 | * unchanged. | |
302 | */ | |
303 | if ((ACPI_GET_DESCRIPTOR_TYPE | |
304 | (walk_state->results->results.obj_desc[0]) == | |
305 | ACPI_DESC_TYPE_OPERAND) | |
306 | && ((walk_state->results->results.obj_desc[0])-> | |
307 | common.type == ACPI_TYPE_LOCAL_REFERENCE) | |
308 | && ((walk_state->results->results.obj_desc[0])-> | |
309 | reference.class != ACPI_REFCLASS_INDEX)) { | |
310 | status = | |
311 | acpi_ex_resolve_to_value(&walk_state-> | |
312 | results->results. | |
313 | obj_desc[0], | |
314 | walk_state); | |
315 | if (ACPI_FAILURE(status)) { | |
316 | return (status); | |
317 | } | |
318 | } | |
319 | ||
320 | walk_state->return_desc = | |
321 | walk_state->results->results.obj_desc[0]; | |
322 | } else { | |
323 | /* No return operand */ | |
324 | ||
325 | if (walk_state->num_operands) { | |
326 | acpi_ut_remove_reference(walk_state-> | |
327 | operands[0]); | |
328 | } | |
329 | ||
330 | walk_state->operands[0] = NULL; | |
331 | walk_state->num_operands = 0; | |
332 | walk_state->return_desc = NULL; | |
333 | } | |
334 | ||
335 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, | |
336 | "Completed RETURN_OP State=%p, RetVal=%p\n", | |
337 | walk_state, walk_state->return_desc)); | |
338 | ||
339 | /* End the control method execution right now */ | |
340 | ||
341 | status = AE_CTRL_TERMINATE; | |
342 | break; | |
343 | ||
344 | case AML_NOOP_OP: | |
345 | ||
346 | /* Just do nothing! */ | |
347 | break; | |
348 | ||
349 | case AML_BREAK_POINT_OP: | |
350 | ||
351 | /* | |
352 | * Set the single-step flag. This will cause the debugger (if present) | |
353 | * to break to the console within the AML debugger at the start of the | |
354 | * next AML instruction. | |
355 | */ | |
356 | ACPI_DEBUGGER_EXEC(acpi_gbl_cm_single_step = TRUE); | |
357 | ACPI_DEBUGGER_EXEC(acpi_os_printf | |
358 | ("**break** Executed AML BreakPoint opcode\n")); | |
359 | ||
360 | /* Call to the OSL in case OS wants a piece of the action */ | |
361 | ||
362 | status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT, | |
363 | "Executed AML Breakpoint opcode"); | |
364 | break; | |
365 | ||
366 | case AML_BREAK_OP: | |
367 | case AML_CONTINUE_OP: /* ACPI 2.0 */ | |
368 | ||
369 | /* Pop and delete control states until we find a while */ | |
370 | ||
371 | while (walk_state->control_state && | |
372 | (walk_state->control_state->control.opcode != | |
373 | AML_WHILE_OP)) { | |
374 | control_state = | |
375 | acpi_ut_pop_generic_state(&walk_state-> | |
376 | control_state); | |
377 | acpi_ut_delete_generic_state(control_state); | |
378 | } | |
379 | ||
380 | /* No while found? */ | |
381 | ||
382 | if (!walk_state->control_state) { | |
383 | return (AE_AML_NO_WHILE); | |
384 | } | |
385 | ||
386 | /* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */ | |
387 | ||
388 | walk_state->aml_last_while = | |
389 | walk_state->control_state->control.package_end; | |
390 | ||
391 | /* Return status depending on opcode */ | |
392 | ||
393 | if (op->common.aml_opcode == AML_BREAK_OP) { | |
394 | status = AE_CTRL_BREAK; | |
395 | } else { | |
396 | status = AE_CTRL_CONTINUE; | |
397 | } | |
398 | break; | |
399 | ||
400 | default: | |
401 | ||
402 | ACPI_ERROR((AE_INFO, "Unknown control opcode=0x%X Op=%p", | |
403 | op->common.aml_opcode, op)); | |
404 | ||
405 | status = AE_AML_BAD_OPCODE; | |
406 | break; | |
407 | } | |
408 | ||
409 | return (status); | |
410 | } |