1 /******************************************************************************
2 *
3 * Module Name: dscontrol - Support for execution control opcodes -
4 * if/else/while/return
5 *
6 *****************************************************************************/
7
8 /*
9 * Copyright (C) 2000 - 2013, 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 * If this is an additional iteration of a while loop, continue.
91 * There is no need to allocate a new control state.
92 */
93 if (WalkState->ControlState)
94 {
95 if (WalkState->ControlState->Control.AmlPredicateStart ==
96 (WalkState->ParserState.Aml - 1))
97 {
98 /* Reset the state to start-of-loop */
99
100 WalkState->ControlState->Common.State =
101 ACPI_CONTROL_CONDITIONAL_EXECUTING;
102 break;
103 }
104 }
105
106 /*lint -fallthrough */
107
108 case AML_IF_OP:
109 /*
110 * IF/WHILE: Create a new control state to manage these
111 * constructs. We need to manage these as a stack, in order
112 * to handle nesting.
113 */
114 ControlState = AcpiUtCreateControlState ();
115 if (!ControlState)
116 {
117 Status = AE_NO_MEMORY;
118 break;
119 }
120 /*
121 * Save a pointer to the predicate for multiple executions
122 * of a loop
123 */
124 ControlState->Control.AmlPredicateStart = WalkState->ParserState.Aml - 1;
125 ControlState->Control.PackageEnd = WalkState->ParserState.PkgEnd;
126 ControlState->Control.Opcode = Op->Common.AmlOpcode;
127
128
129 /* Push the control state on this walk's control stack */
130
131 AcpiUtPushGenericState (&WalkState->ControlState, ControlState);
132 break;
133
134 case AML_ELSE_OP:
135
136 /* Predicate is in the state object */
137 /* If predicate is true, the IF was executed, ignore ELSE part */
138
139 if (WalkState->LastPredicate)
140 {
141 Status = AE_CTRL_TRUE;
142 }
143
144 break;
145
146 case AML_RETURN_OP:
147
148 break;
149
150 default:
151
152 break;
153 }
154
155 return (Status);
156 }
157
158
159 /*******************************************************************************
160 *
161 * FUNCTION: AcpiDsExecEndControlOp
162 *
163 * PARAMETERS: WalkList - The list that owns the walk stack
164 * Op - The control Op
165 *
166 * RETURN: Status
167 *
168 * DESCRIPTION: Handles all control ops encountered during control method
169 * execution.
170 *
171 ******************************************************************************/
172
173 ACPI_STATUS
174 AcpiDsExecEndControlOp (
175 ACPI_WALK_STATE *WalkState,
176 ACPI_PARSE_OBJECT *Op)
177 {
178 ACPI_STATUS Status = AE_OK;
179 ACPI_GENERIC_STATE *ControlState;
180
181
182 ACPI_FUNCTION_NAME (DsExecEndControlOp);
183
184
185 switch (Op->Common.AmlOpcode)
186 {
187 case AML_IF_OP:
188
189 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", Op));
190
191 /*
192 * Save the result of the predicate in case there is an
193 * ELSE to come
194 */
195 WalkState->LastPredicate =
196 (BOOLEAN) WalkState->ControlState->Common.Value;
197
198 /*
199 * Pop the control state that was created at the start
200 * of the IF and free it
201 */
202 ControlState = AcpiUtPopGenericState (&WalkState->ControlState);
203 AcpiUtDeleteGenericState (ControlState);
204 break;
205
206 case AML_ELSE_OP:
207
208 break;
209
210 case AML_WHILE_OP:
211
212 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", Op));
213
214 ControlState = WalkState->ControlState;
215 if (ControlState->Common.Value)
216 {
217 /* Predicate was true, the body of the loop was just executed */
218
219 /*
220 * This loop counter mechanism allows the interpreter to escape
221 * possibly infinite loops. This can occur in poorly written AML
222 * when the hardware does not respond within a while loop and the
223 * loop does not implement a timeout.
224 */
225 ControlState->Control.LoopCount++;
226 if (ControlState->Control.LoopCount > ACPI_MAX_LOOP_ITERATIONS)
227 {
228 Status = AE_AML_INFINITE_LOOP;
229 break;
230 }
231
232 /*
233 * Go back and evaluate the predicate and maybe execute the loop
234 * another time
235 */
236 Status = AE_CTRL_PENDING;
237 WalkState->AmlLastWhile = ControlState->Control.AmlPredicateStart;
238 break;
239 }
240
241 /* Predicate was false, terminate this while loop */
242
243 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
244 "[WHILE_OP] termination! Op=%p\n",Op));
245
246 /* Pop this control state and free it */
247
248 ControlState = AcpiUtPopGenericState (&WalkState->ControlState);
249 AcpiUtDeleteGenericState (ControlState);
250 break;
251
252 case AML_RETURN_OP:
253
254 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
255 "[RETURN_OP] Op=%p Arg=%p\n",Op, Op->Common.Value.Arg));
256
257 /*
258 * One optional operand -- the return value
259 * It can be either an immediate operand or a result that
260 * has been bubbled up the tree
261 */
262 if (Op->Common.Value.Arg)
263 {
264 /* Since we have a real Return(), delete any implicit return */
265
266 AcpiDsClearImplicitReturn (WalkState);
267
268 /* Return statement has an immediate operand */
269
270 Status = AcpiDsCreateOperands (WalkState, Op->Common.Value.Arg);
271 if (ACPI_FAILURE (Status))
272 {
273 return (Status);
274 }
275
276 /*
277 * If value being returned is a Reference (such as
278 * an arg or local), resolve it now because it may
279 * cease to exist at the end of the method.
280 */
281 Status = AcpiExResolveToValue (&WalkState->Operands [0], WalkState);
282 if (ACPI_FAILURE (Status))
283 {
284 return (Status);
285 }
286
287 /*
288 * Get the return value and save as the last result
289 * value. This is the only place where WalkState->ReturnDesc
290 * is set to anything other than zero!
291 */
292 WalkState->ReturnDesc = WalkState->Operands[0];
293 }
294 else if (WalkState->ResultCount)
295 {
296 /* Since we have a real Return(), delete any implicit return */
297
298 AcpiDsClearImplicitReturn (WalkState);
299
300 /*
301 * The return value has come from a previous calculation.
302 *
303 * If value being returned is a Reference (such as
304 * an arg or local), resolve it now because it may
305 * cease to exist at the end of the method.
306 *
307 * Allow references created by the Index operator to return
308 * unchanged.
309 */
310 if ((ACPI_GET_DESCRIPTOR_TYPE (WalkState->Results->Results.ObjDesc[0]) == ACPI_DESC_TYPE_OPERAND) &&
311 ((WalkState->Results->Results.ObjDesc [0])->Common.Type == ACPI_TYPE_LOCAL_REFERENCE) &&
312 ((WalkState->Results->Results.ObjDesc [0])->Reference.Class != ACPI_REFCLASS_INDEX))
313 {
314 Status = AcpiExResolveToValue (&WalkState->Results->Results.ObjDesc [0], WalkState);
315 if (ACPI_FAILURE (Status))
316 {
317 return (Status);
318 }
319 }
320
321 WalkState->ReturnDesc = WalkState->Results->Results.ObjDesc [0];
322 }
323 else
324 {
325 /* No return operand */
326
327 if (WalkState->NumOperands)
328 {
329 AcpiUtRemoveReference (WalkState->Operands [0]);
330 }
331
332 WalkState->Operands [0] = NULL;
333 WalkState->NumOperands = 0;
334 WalkState->ReturnDesc = NULL;
335 }
336
337
338 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
339 "Completed RETURN_OP State=%p, RetVal=%p\n",
340 WalkState, WalkState->ReturnDesc));
341
342 /* End the control method execution right now */
343
344 Status = AE_CTRL_TERMINATE;
345 break;
346
347 case AML_NOOP_OP:
348
349 /* Just do nothing! */
350
351 break;
352
353 case AML_BREAK_POINT_OP:
354
355 /*
356 * Set the single-step flag. This will cause the debugger (if present)
357 * to break to the console within the AML debugger at the start of the
358 * next AML instruction.
359 */
360 ACPI_DEBUGGER_EXEC (
361 AcpiGbl_CmSingleStep = TRUE);
362 ACPI_DEBUGGER_EXEC (
363 AcpiOsPrintf ("**break** Executed AML BreakPoint opcode\n"));
364
365 /* Call to the OSL in case OS wants a piece of the action */
366
367 Status = AcpiOsSignal (ACPI_SIGNAL_BREAKPOINT,
368 "Executed AML Breakpoint opcode");
369 break;
370
371 case AML_BREAK_OP:
372 case AML_CONTINUE_OP: /* ACPI 2.0 */
373
374 /* Pop and delete control states until we find a while */
375
376 while (WalkState->ControlState &&
377 (WalkState->ControlState->Control.Opcode != AML_WHILE_OP))
378 {
379 ControlState = AcpiUtPopGenericState (&WalkState->ControlState);
380 AcpiUtDeleteGenericState (ControlState);
381 }
382
383 /* No while found? */
384
385 if (!WalkState->ControlState)
386 {
387 return (AE_AML_NO_WHILE);
388 }
389
390 /* Was: WalkState->AmlLastWhile = WalkState->ControlState->Control.AmlPredicateStart; */
391
392 WalkState->AmlLastWhile = WalkState->ControlState->Control.PackageEnd;
393
394 /* Return status depending on opcode */
395
396 if (Op->Common.AmlOpcode == AML_BREAK_OP)
397 {
398 Status = AE_CTRL_BREAK;
399 }
400 else
401 {
402 Status = AE_CTRL_CONTINUE;
403 }
404 break;
405
406 default:
407
408 ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p",
409 Op->Common.AmlOpcode, Op));
410
411 Status = AE_AML_BAD_OPCODE;
412 break;
413 }
414
415 return (Status);
416 }