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 #define __DSCONTROL_C__
46
47 #include "acpi.h"
48 #include "accommon.h"
49 #include "amlcode.h"
50 #include "acdispat.h"
51 #include "acinterp.h"
52
53 #define _COMPONENT ACPI_DISPATCHER
54 ACPI_MODULE_NAME ("dscontrol")
55
56
57 /*******************************************************************************
58 *
59 * FUNCTION: AcpiDsExecBeginControlOp
60 *
61 * PARAMETERS: WalkList - The list that owns the walk stack
62 * Op - The control Op
63 *
64 * RETURN: Status
65 *
66 * DESCRIPTION: Handles all control ops encountered during control method
67 * execution.
68 *
69 ******************************************************************************/
70
71 ACPI_STATUS
72 AcpiDsExecBeginControlOp (
73 ACPI_WALK_STATE *WalkState,
74 ACPI_PARSE_OBJECT *Op)
75 {
76 ACPI_STATUS Status = AE_OK;
77 ACPI_GENERIC_STATE *ControlState;
78
79
80 ACPI_FUNCTION_NAME (DsExecBeginControlOp);
81
82
83 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n",
84 Op, Op->Common.AmlOpcode, WalkState));
85
86 switch (Op->Common.AmlOpcode)
87 {
88 case AML_WHILE_OP:
89
90 /*
91 * If this is an additional iteration of a while loop, continue.
92 * There is no need to allocate a new control state.
93 */
94 if (WalkState->ControlState)
95 {
96 if (WalkState->ControlState->Control.AmlPredicateStart ==
97 (WalkState->ParserState.Aml - 1))
98 {
99 /* Reset the state to start-of-loop */
100
101 WalkState->ControlState->Common.State =
102 ACPI_CONTROL_CONDITIONAL_EXECUTING;
103 break;
104 }
105 }
106
107 /*lint -fallthrough */
108
109 case AML_IF_OP:
110
111 /*
112 * IF/WHILE: Create a new control state to manage these
113 * constructs. We need to manage these as a stack, in order
114 * to handle nesting.
115 */
116 ControlState = AcpiUtCreateControlState ();
117 if (!ControlState)
118 {
119 Status = AE_NO_MEMORY;
120 break;
121 }
122 /*
123 * Save a pointer to the predicate for multiple executions
124 * of a loop
125 */
126 ControlState->Control.AmlPredicateStart = WalkState->ParserState.Aml - 1;
127 ControlState->Control.PackageEnd = WalkState->ParserState.PkgEnd;
128 ControlState->Control.Opcode = Op->Common.AmlOpcode;
129
130
131 /* Push the control state on this walk's control stack */
132
133 AcpiUtPushGenericState (&WalkState->ControlState, ControlState);
134 break;
135
136 case AML_ELSE_OP:
137
138 /* Predicate is in the state object */
139 /* If predicate is true, the IF was executed, ignore ELSE part */
140
141 if (WalkState->LastPredicate)
142 {
143 Status = AE_CTRL_TRUE;
144 }
145
146 break;
147
148 case AML_RETURN_OP:
149
150 break;
151
152 default:
153 break;
154 }
155
156 return (Status);
157 }
158
159
160 /*******************************************************************************
161 *
162 * FUNCTION: AcpiDsExecEndControlOp
163 *
164 * PARAMETERS: WalkList - The list that owns the walk stack
165 * Op - The control Op
166 *
167 * RETURN: Status
168 *
169 * DESCRIPTION: Handles all control ops encountered during control method
170 * execution.
171 *
172 ******************************************************************************/
173
174 ACPI_STATUS
175 AcpiDsExecEndControlOp (
176 ACPI_WALK_STATE *WalkState,
177 ACPI_PARSE_OBJECT *Op)
178 {
179 ACPI_STATUS Status = AE_OK;
180 ACPI_GENERIC_STATE *ControlState;
181
182
183 ACPI_FUNCTION_NAME (DsExecEndControlOp);
184
185
186 switch (Op->Common.AmlOpcode)
187 {
188 case AML_IF_OP:
189
190 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", Op));
191
192 /*
193 * Save the result of the predicate in case there is an
194 * ELSE to come
195 */
196 WalkState->LastPredicate =
197 (BOOLEAN) WalkState->ControlState->Common.Value;
198
199 /*
200 * Pop the control state that was created at the start
201 * of the IF and free it
202 */
203 ControlState = AcpiUtPopGenericState (&WalkState->ControlState);
204 AcpiUtDeleteGenericState (ControlState);
205 break;
206
207
208 case AML_ELSE_OP:
209
210 break;
211
212
213 case AML_WHILE_OP:
214
215 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", Op));
216
217 ControlState = WalkState->ControlState;
218 if (ControlState->Common.Value)
219 {
220 /* Predicate was true, the body of the loop was just executed */
221
222 /*
223 * This loop counter mechanism allows the interpreter to escape
224 * possibly infinite loops. This can occur in poorly written AML
225 * when the hardware does not respond within a while loop and the
226 * loop does not implement a timeout.
227 */
228 ControlState->Control.LoopCount++;
229 if (ControlState->Control.LoopCount > ACPI_MAX_LOOP_ITERATIONS)
230 {
231 Status = AE_AML_INFINITE_LOOP;
232 break;
233 }
234
235 /*
236 * Go back and evaluate the predicate and maybe execute the loop
237 * another time
238 */
239 Status = AE_CTRL_PENDING;
240 WalkState->AmlLastWhile = ControlState->Control.AmlPredicateStart;
241 break;
242 }
243
244 /* Predicate was false, terminate this while loop */
245
246 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
247 "[WHILE_OP] termination! Op=%p\n",Op));
248
249 /* Pop this control state and free it */
250
251 ControlState = AcpiUtPopGenericState (&WalkState->ControlState);
252 AcpiUtDeleteGenericState (ControlState);
253 break;
254
255
256 case AML_RETURN_OP:
257
258 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
259 "[RETURN_OP] Op=%p Arg=%p\n",Op, Op->Common.Value.Arg));
260
261 /*
262 * One optional operand -- the return value
263 * It can be either an immediate operand or a result that
264 * has been bubbled up the tree
265 */
266 if (Op->Common.Value.Arg)
267 {
268 /* Since we have a real Return(), delete any implicit return */
269
270 AcpiDsClearImplicitReturn (WalkState);
271
272 /* Return statement has an immediate operand */
273
274 Status = AcpiDsCreateOperands (WalkState, Op->Common.Value.Arg);
275 if (ACPI_FAILURE (Status))
276 {
277 return (Status);
278 }
279
280 /*
281 * If value being returned is a Reference (such as
282 * an arg or local), resolve it now because it may
283 * cease to exist at the end of the method.
284 */
285 Status = AcpiExResolveToValue (&WalkState->Operands [0], WalkState);
286 if (ACPI_FAILURE (Status))
287 {
288 return (Status);
289 }
290
291 /*
292 * Get the return value and save as the last result
293 * value. This is the only place where WalkState->ReturnDesc
294 * is set to anything other than zero!
295 */
296 WalkState->ReturnDesc = WalkState->Operands[0];
297 }
298 else if (WalkState->ResultCount)
299 {
300 /* Since we have a real Return(), delete any implicit return */
301
302 AcpiDsClearImplicitReturn (WalkState);
303
304 /*
305 * The return value has come from a previous calculation.
306 *
307 * If value being returned is a Reference (such as
308 * an arg or local), resolve it now because it may
309 * cease to exist at the end of the method.
310 *
311 * Allow references created by the Index operator to return
312 * unchanged.
313 */
314 if ((ACPI_GET_DESCRIPTOR_TYPE (WalkState->Results->Results.ObjDesc[0]) == ACPI_DESC_TYPE_OPERAND) &&
315 ((WalkState->Results->Results.ObjDesc [0])->Common.Type == ACPI_TYPE_LOCAL_REFERENCE) &&
316 ((WalkState->Results->Results.ObjDesc [0])->Reference.Class != ACPI_REFCLASS_INDEX))
317 {
318 Status = AcpiExResolveToValue (&WalkState->Results->Results.ObjDesc [0], WalkState);
319 if (ACPI_FAILURE (Status))
320 {
321 return (Status);
322 }
323 }
324
325 WalkState->ReturnDesc = WalkState->Results->Results.ObjDesc [0];
326 }
327 else
328 {
329 /* No return operand */
330
331 if (WalkState->NumOperands)
332 {
333 AcpiUtRemoveReference (WalkState->Operands [0]);
334 }
335
336 WalkState->Operands [0] = NULL;
337 WalkState->NumOperands = 0;
338 WalkState->ReturnDesc = NULL;
339 }
340
341
342 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
343 "Completed RETURN_OP State=%p, RetVal=%p\n",
344 WalkState, WalkState->ReturnDesc));
345
346 /* End the control method execution right now */
347
348 Status = AE_CTRL_TERMINATE;
349 break;
350
351
352 case AML_NOOP_OP:
353
354 /* Just do nothing! */
355 break;
356
357
358 case AML_BREAK_POINT_OP:
359
360 /*
361 * Set the single-step flag. This will cause the debugger (if present)
362 * to break to the console within the AML debugger at the start of the
363 * next AML instruction.
364 */
365 ACPI_DEBUGGER_EXEC (
366 AcpiGbl_CmSingleStep = TRUE);
367 ACPI_DEBUGGER_EXEC (
368 AcpiOsPrintf ("**break** Executed AML BreakPoint opcode\n"));
369
370 /* Call to the OSL in case OS wants a piece of the action */
371
372 Status = AcpiOsSignal (ACPI_SIGNAL_BREAKPOINT,
373 "Executed AML Breakpoint opcode");
374 break;
375
376
377 case AML_BREAK_OP:
378 case AML_CONTINUE_OP: /* ACPI 2.0 */
379
380
381 /* Pop and delete control states until we find a while */
382
383 while (WalkState->ControlState &&
384 (WalkState->ControlState->Control.Opcode != AML_WHILE_OP))
385 {
386 ControlState = AcpiUtPopGenericState (&WalkState->ControlState);
387 AcpiUtDeleteGenericState (ControlState);
388 }
389
390 /* No while found? */
391
392 if (!WalkState->ControlState)
393 {
394 return (AE_AML_NO_WHILE);
395 }
396
397 /* Was: WalkState->AmlLastWhile = WalkState->ControlState->Control.AmlPredicateStart; */
398
399 WalkState->AmlLastWhile = WalkState->ControlState->Control.PackageEnd;
400
401 /* Return status depending on opcode */
402
403 if (Op->Common.AmlOpcode == AML_BREAK_OP)
404 {
405 Status = AE_CTRL_BREAK;
406 }
407 else
408 {
409 Status = AE_CTRL_CONTINUE;
410 }
411 break;
412
413
414 default:
415
416 ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p",
417 Op->Common.AmlOpcode, Op));
418
419 Status = AE_AML_BAD_OPCODE;
420 break;
421 }
422
423 return (Status);
424 }