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1 | /****************************************************************************** |
2 | * | |
3 | * Module Name: dscontrol - Support for execution control opcodes - | |
4 | * if/else/while/return | |
5 | * | |
6 | *****************************************************************************/ | |
7 | ||
8 | /* | |
25f044e6 | 9 | * Copyright (C) 2000 - 2013, Intel Corp. |
9ad19ac4 BM |
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 | |
ba494bee | 59 | * op - The control Op |
9ad19ac4 BM |
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: | |
9ad19ac4 BM |
81 | /* |
82 | * If this is an additional iteration of a while loop, continue. | |
83 | * There is no need to allocate a new control state. | |
84 | */ | |
85 | if (walk_state->control_state) { | |
86 | if (walk_state->control_state->control. | |
87 | aml_predicate_start == | |
88 | (walk_state->parser_state.aml - 1)) { | |
89 | ||
90 | /* Reset the state to start-of-loop */ | |
91 | ||
92 | walk_state->control_state->common.state = | |
93 | ACPI_CONTROL_CONDITIONAL_EXECUTING; | |
94 | break; | |
95 | } | |
96 | } | |
97 | ||
98 | /*lint -fallthrough */ | |
99 | ||
100 | case AML_IF_OP: | |
9ad19ac4 BM |
101 | /* |
102 | * IF/WHILE: Create a new control state to manage these | |
103 | * constructs. We need to manage these as a stack, in order | |
104 | * to handle nesting. | |
105 | */ | |
106 | control_state = acpi_ut_create_control_state(); | |
107 | if (!control_state) { | |
108 | status = AE_NO_MEMORY; | |
109 | break; | |
110 | } | |
111 | /* | |
112 | * Save a pointer to the predicate for multiple executions | |
113 | * of a loop | |
114 | */ | |
115 | control_state->control.aml_predicate_start = | |
116 | walk_state->parser_state.aml - 1; | |
117 | control_state->control.package_end = | |
118 | walk_state->parser_state.pkg_end; | |
119 | control_state->control.opcode = op->common.aml_opcode; | |
120 | ||
121 | /* Push the control state on this walk's control stack */ | |
122 | ||
123 | acpi_ut_push_generic_state(&walk_state->control_state, | |
124 | control_state); | |
125 | break; | |
126 | ||
127 | case AML_ELSE_OP: | |
128 | ||
129 | /* Predicate is in the state object */ | |
130 | /* If predicate is true, the IF was executed, ignore ELSE part */ | |
131 | ||
132 | if (walk_state->last_predicate) { | |
133 | status = AE_CTRL_TRUE; | |
134 | } | |
135 | ||
136 | break; | |
137 | ||
138 | case AML_RETURN_OP: | |
139 | ||
140 | break; | |
141 | ||
142 | default: | |
1d1ea1b7 | 143 | |
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144 | break; |
145 | } | |
146 | ||
147 | return (status); | |
148 | } | |
149 | ||
150 | /******************************************************************************* | |
151 | * | |
152 | * FUNCTION: acpi_ds_exec_end_control_op | |
153 | * | |
154 | * PARAMETERS: walk_list - The list that owns the walk stack | |
ba494bee | 155 | * op - The control Op |
9ad19ac4 BM |
156 | * |
157 | * RETURN: Status | |
158 | * | |
159 | * DESCRIPTION: Handles all control ops encountered during control method | |
160 | * execution. | |
161 | * | |
162 | ******************************************************************************/ | |
163 | ||
164 | acpi_status | |
165 | acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state, | |
166 | union acpi_parse_object * op) | |
167 | { | |
168 | acpi_status status = AE_OK; | |
169 | union acpi_generic_state *control_state; | |
170 | ||
171 | ACPI_FUNCTION_NAME(ds_exec_end_control_op); | |
172 | ||
173 | switch (op->common.aml_opcode) { | |
174 | case AML_IF_OP: | |
175 | ||
176 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op)); | |
177 | ||
178 | /* | |
179 | * Save the result of the predicate in case there is an | |
180 | * ELSE to come | |
181 | */ | |
182 | walk_state->last_predicate = | |
183 | (u8)walk_state->control_state->common.value; | |
184 | ||
185 | /* | |
186 | * Pop the control state that was created at the start | |
187 | * of the IF and free it | |
188 | */ | |
189 | control_state = | |
190 | acpi_ut_pop_generic_state(&walk_state->control_state); | |
191 | acpi_ut_delete_generic_state(control_state); | |
192 | break; | |
193 | ||
194 | case AML_ELSE_OP: | |
195 | ||
196 | break; | |
197 | ||
198 | case AML_WHILE_OP: | |
199 | ||
200 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op)); | |
201 | ||
202 | control_state = walk_state->control_state; | |
203 | if (control_state->common.value) { | |
204 | ||
205 | /* Predicate was true, the body of the loop was just executed */ | |
206 | ||
207 | /* | |
208 | * This loop counter mechanism allows the interpreter to escape | |
209 | * possibly infinite loops. This can occur in poorly written AML | |
210 | * when the hardware does not respond within a while loop and the | |
211 | * loop does not implement a timeout. | |
212 | */ | |
213 | control_state->control.loop_count++; | |
214 | if (control_state->control.loop_count > | |
215 | ACPI_MAX_LOOP_ITERATIONS) { | |
216 | status = AE_AML_INFINITE_LOOP; | |
217 | break; | |
218 | } | |
219 | ||
220 | /* | |
221 | * Go back and evaluate the predicate and maybe execute the loop | |
222 | * another time | |
223 | */ | |
224 | status = AE_CTRL_PENDING; | |
225 | walk_state->aml_last_while = | |
226 | control_state->control.aml_predicate_start; | |
227 | break; | |
228 | } | |
229 | ||
230 | /* Predicate was false, terminate this while loop */ | |
231 | ||
232 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, | |
233 | "[WHILE_OP] termination! Op=%p\n", op)); | |
234 | ||
235 | /* Pop this control state and free it */ | |
236 | ||
237 | control_state = | |
238 | acpi_ut_pop_generic_state(&walk_state->control_state); | |
239 | acpi_ut_delete_generic_state(control_state); | |
240 | break; | |
241 | ||
242 | case AML_RETURN_OP: | |
243 | ||
244 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, | |
245 | "[RETURN_OP] Op=%p Arg=%p\n", op, | |
246 | op->common.value.arg)); | |
247 | ||
248 | /* | |
249 | * One optional operand -- the return value | |
250 | * It can be either an immediate operand or a result that | |
251 | * has been bubbled up the tree | |
252 | */ | |
253 | if (op->common.value.arg) { | |
254 | ||
255 | /* Since we have a real Return(), delete any implicit return */ | |
256 | ||
257 | acpi_ds_clear_implicit_return(walk_state); | |
258 | ||
259 | /* Return statement has an immediate operand */ | |
260 | ||
261 | status = | |
262 | acpi_ds_create_operands(walk_state, | |
263 | op->common.value.arg); | |
264 | if (ACPI_FAILURE(status)) { | |
265 | return (status); | |
266 | } | |
267 | ||
268 | /* | |
269 | * If value being returned is a Reference (such as | |
270 | * an arg or local), resolve it now because it may | |
271 | * cease to exist at the end of the method. | |
272 | */ | |
273 | status = | |
274 | acpi_ex_resolve_to_value(&walk_state->operands[0], | |
275 | walk_state); | |
276 | if (ACPI_FAILURE(status)) { | |
277 | return (status); | |
278 | } | |
279 | ||
280 | /* | |
281 | * Get the return value and save as the last result | |
73a3090a | 282 | * value. This is the only place where walk_state->return_desc |
9ad19ac4 BM |
283 | * is set to anything other than zero! |
284 | */ | |
285 | walk_state->return_desc = walk_state->operands[0]; | |
286 | } else if (walk_state->result_count) { | |
287 | ||
288 | /* Since we have a real Return(), delete any implicit return */ | |
289 | ||
290 | acpi_ds_clear_implicit_return(walk_state); | |
291 | ||
292 | /* | |
293 | * The return value has come from a previous calculation. | |
294 | * | |
295 | * If value being returned is a Reference (such as | |
296 | * an arg or local), resolve it now because it may | |
297 | * cease to exist at the end of the method. | |
298 | * | |
299 | * Allow references created by the Index operator to return | |
300 | * unchanged. | |
301 | */ | |
302 | if ((ACPI_GET_DESCRIPTOR_TYPE | |
303 | (walk_state->results->results.obj_desc[0]) == | |
304 | ACPI_DESC_TYPE_OPERAND) | |
305 | && ((walk_state->results->results.obj_desc[0])-> | |
306 | common.type == ACPI_TYPE_LOCAL_REFERENCE) | |
307 | && ((walk_state->results->results.obj_desc[0])-> | |
308 | reference.class != ACPI_REFCLASS_INDEX)) { | |
309 | status = | |
310 | acpi_ex_resolve_to_value(&walk_state-> | |
311 | results->results. | |
312 | obj_desc[0], | |
313 | walk_state); | |
314 | if (ACPI_FAILURE(status)) { | |
315 | return (status); | |
316 | } | |
317 | } | |
318 | ||
319 | walk_state->return_desc = | |
320 | walk_state->results->results.obj_desc[0]; | |
321 | } else { | |
322 | /* No return operand */ | |
323 | ||
324 | if (walk_state->num_operands) { | |
325 | acpi_ut_remove_reference(walk_state-> | |
326 | operands[0]); | |
327 | } | |
328 | ||
329 | walk_state->operands[0] = NULL; | |
330 | walk_state->num_operands = 0; | |
331 | walk_state->return_desc = NULL; | |
332 | } | |
333 | ||
334 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, | |
335 | "Completed RETURN_OP State=%p, RetVal=%p\n", | |
336 | walk_state, walk_state->return_desc)); | |
337 | ||
338 | /* End the control method execution right now */ | |
339 | ||
340 | status = AE_CTRL_TERMINATE; | |
341 | break; | |
342 | ||
343 | case AML_NOOP_OP: | |
344 | ||
345 | /* Just do nothing! */ | |
1d1ea1b7 | 346 | |
9ad19ac4 BM |
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 | } |