1 | /****************************************************************************** |
2 | * |
3 | * Module Name: dscontrol - Support for execution control opcodes - |
4 | * if/else/while/return |
5 | * |
6 | *****************************************************************************/ |
7 | |
8 | /* |
9 | * Copyright (C) 2000 - 2016, 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.h" |
46 | #include "accommon.h" |
47 | #include "amlcode.h" |
48 | #include "acdispat.h" |
49 | #include "acinterp.h" |
50 | #include "acdebug.h" |
51 | |
52 | #define _COMPONENT ACPI_DISPATCHER |
53 | ACPI_MODULE_NAME ("dscontrol" ) |
54 | |
55 | |
56 | /******************************************************************************* |
57 | * |
58 | * FUNCTION: AcpiDsExecBeginControlOp |
59 | * |
60 | * PARAMETERS: WalkList - The list that owns the walk stack |
61 | * Op - The control Op |
62 | * |
63 | * RETURN: Status |
64 | * |
65 | * DESCRIPTION: Handles all control ops encountered during control method |
66 | * execution. |
67 | * |
68 | ******************************************************************************/ |
69 | |
70 | ACPI_STATUS |
71 | AcpiDsExecBeginControlOp ( |
72 | ACPI_WALK_STATE *WalkState, |
73 | ACPI_PARSE_OBJECT *Op) |
74 | { |
75 | ACPI_STATUS Status = AE_OK; |
76 | ACPI_GENERIC_STATE *ControlState; |
77 | |
78 | |
79 | ACPI_FUNCTION_NAME (DsExecBeginControlOp); |
80 | |
81 | |
82 | ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n" , |
83 | Op, Op->Common.AmlOpcode, WalkState)); |
84 | |
85 | switch (Op->Common.AmlOpcode) |
86 | { |
87 | case AML_WHILE_OP: |
88 | /* |
89 | * If this is an additional iteration of a while loop, continue. |
90 | * There is no need to allocate a new control state. |
91 | */ |
92 | if (WalkState->ControlState) |
93 | { |
94 | if (WalkState->ControlState->Control.AmlPredicateStart == |
95 | (WalkState->ParserState.Aml - 1)) |
96 | { |
97 | /* Reset the state to start-of-loop */ |
98 | |
99 | WalkState->ControlState->Common.State = |
100 | ACPI_CONTROL_CONDITIONAL_EXECUTING; |
101 | break; |
102 | } |
103 | } |
104 | |
105 | /*lint -fallthrough */ |
106 | |
107 | case AML_IF_OP: |
108 | /* |
109 | * IF/WHILE: Create a new control state to manage these |
110 | * constructs. We need to manage these as a stack, in order |
111 | * to handle nesting. |
112 | */ |
113 | ControlState = AcpiUtCreateControlState (); |
114 | if (!ControlState) |
115 | { |
116 | Status = AE_NO_MEMORY; |
117 | break; |
118 | } |
119 | /* |
120 | * Save a pointer to the predicate for multiple executions |
121 | * of a loop |
122 | */ |
123 | ControlState->Control.AmlPredicateStart = |
124 | WalkState->ParserState.Aml - 1; |
125 | ControlState->Control.PackageEnd = |
126 | WalkState->ParserState.PkgEnd; |
127 | ControlState->Control.Opcode = |
128 | 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 | |
154 | break; |
155 | } |
156 | |
157 | return (Status); |
158 | } |
159 | |
160 | |
161 | /******************************************************************************* |
162 | * |
163 | * FUNCTION: AcpiDsExecEndControlOp |
164 | * |
165 | * PARAMETERS: WalkList - The list that owns the walk stack |
166 | * Op - The control Op |
167 | * |
168 | * RETURN: Status |
169 | * |
170 | * DESCRIPTION: Handles all control ops encountered during control method |
171 | * execution. |
172 | * |
173 | ******************************************************************************/ |
174 | |
175 | ACPI_STATUS |
176 | AcpiDsExecEndControlOp ( |
177 | ACPI_WALK_STATE *WalkState, |
178 | ACPI_PARSE_OBJECT *Op) |
179 | { |
180 | ACPI_STATUS Status = AE_OK; |
181 | ACPI_GENERIC_STATE *ControlState; |
182 | |
183 | |
184 | ACPI_FUNCTION_NAME (DsExecEndControlOp); |
185 | |
186 | |
187 | switch (Op->Common.AmlOpcode) |
188 | { |
189 | case AML_IF_OP: |
190 | |
191 | ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n" , Op)); |
192 | |
193 | /* |
194 | * Save the result of the predicate in case there is an |
195 | * ELSE to come |
196 | */ |
197 | WalkState->LastPredicate = |
198 | (BOOLEAN) WalkState->ControlState->Common.Value; |
199 | |
200 | /* |
201 | * Pop the control state that was created at the start |
202 | * of the IF and free it |
203 | */ |
204 | ControlState = AcpiUtPopGenericState (&WalkState->ControlState); |
205 | AcpiUtDeleteGenericState (ControlState); |
206 | break; |
207 | |
208 | case AML_ELSE_OP: |
209 | |
210 | break; |
211 | |
212 | case AML_WHILE_OP: |
213 | |
214 | ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n" , Op)); |
215 | |
216 | ControlState = WalkState->ControlState; |
217 | if (ControlState->Common.Value) |
218 | { |
219 | /* Predicate was true, the body of the loop was just executed */ |
220 | |
221 | /* |
222 | * This loop counter mechanism allows the interpreter to escape |
223 | * possibly infinite loops. This can occur in poorly written AML |
224 | * when the hardware does not respond within a while loop and the |
225 | * loop does not implement a timeout. |
226 | */ |
227 | ControlState->Control.LoopCount++; |
228 | if (ControlState->Control.LoopCount > AcpiGbl_MaxLoopIterations) |
229 | { |
230 | Status = AE_AML_INFINITE_LOOP; |
231 | break; |
232 | } |
233 | |
234 | /* |
235 | * Go back and evaluate the predicate and maybe execute the loop |
236 | * another time |
237 | */ |
238 | Status = AE_CTRL_PENDING; |
239 | WalkState->AmlLastWhile = |
240 | 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 | case AML_RETURN_OP: |
256 | |
257 | ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, |
258 | "[RETURN_OP] Op=%p Arg=%p\n" ,Op, Op->Common.Value.Arg)); |
259 | |
260 | /* |
261 | * One optional operand -- the return value |
262 | * It can be either an immediate operand or a result that |
263 | * has been bubbled up the tree |
264 | */ |
265 | if (Op->Common.Value.Arg) |
266 | { |
267 | /* Since we have a real Return(), delete any implicit return */ |
268 | |
269 | AcpiDsClearImplicitReturn (WalkState); |
270 | |
271 | /* Return statement has an immediate operand */ |
272 | |
273 | Status = AcpiDsCreateOperands (WalkState, Op->Common.Value.Arg); |
274 | if (ACPI_FAILURE (Status)) |
275 | { |
276 | return (Status); |
277 | } |
278 | |
279 | /* |
280 | * If value being returned is a Reference (such as |
281 | * an arg or local), resolve it now because it may |
282 | * cease to exist at the end of the method. |
283 | */ |
284 | Status = AcpiExResolveToValue ( |
285 | &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]) == |
315 | ACPI_DESC_TYPE_OPERAND) && |
316 | ((WalkState->Results->Results.ObjDesc [0])->Common.Type == |
317 | ACPI_TYPE_LOCAL_REFERENCE) && |
318 | ((WalkState->Results->Results.ObjDesc [0])->Reference.Class != |
319 | ACPI_REFCLASS_INDEX)) |
320 | { |
321 | Status = AcpiExResolveToValue ( |
322 | &WalkState->Results->Results.ObjDesc [0], WalkState); |
323 | if (ACPI_FAILURE (Status)) |
324 | { |
325 | return (Status); |
326 | } |
327 | } |
328 | |
329 | WalkState->ReturnDesc = WalkState->Results->Results.ObjDesc [0]; |
330 | } |
331 | else |
332 | { |
333 | /* No return operand */ |
334 | |
335 | if (WalkState->NumOperands) |
336 | { |
337 | AcpiUtRemoveReference (WalkState->Operands [0]); |
338 | } |
339 | |
340 | WalkState->Operands[0] = NULL; |
341 | WalkState->NumOperands = 0; |
342 | WalkState->ReturnDesc = NULL; |
343 | } |
344 | |
345 | |
346 | ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, |
347 | "Completed RETURN_OP State=%p, RetVal=%p\n" , |
348 | WalkState, WalkState->ReturnDesc)); |
349 | |
350 | /* End the control method execution right now */ |
351 | |
352 | Status = AE_CTRL_TERMINATE; |
353 | break; |
354 | |
355 | case AML_NOOP_OP: |
356 | |
357 | /* Just do nothing! */ |
358 | |
359 | break; |
360 | |
361 | case AML_BREAK_POINT_OP: |
362 | |
363 | AcpiDbSignalBreakPoint (WalkState); |
364 | |
365 | /* Call to the OSL in case OS wants a piece of the action */ |
366 | |
367 | Status = AcpiOsSignal (ACPI_SIGNAL_BREAKPOINT, |
368 | __UNCONST("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 = |
393 | WalkState->ControlState->Control.PackageEnd; |
394 | |
395 | /* Return status depending on opcode */ |
396 | |
397 | if (Op->Common.AmlOpcode == AML_BREAK_OP) |
398 | { |
399 | Status = AE_CTRL_BREAK; |
400 | } |
401 | else |
402 | { |
403 | Status = AE_CTRL_CONTINUE; |
404 | } |
405 | break; |
406 | |
407 | default: |
408 | |
409 | ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p" , |
410 | Op->Common.AmlOpcode, Op)); |
411 | |
412 | Status = AE_AML_BAD_OPCODE; |
413 | break; |
414 | } |
415 | |
416 | return (Status); |
417 | } |
418 | |