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
71ACPI_STATUS
72AcpiDsExecBeginControlOp (
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
174ACPI_STATUS
175AcpiDsExecEndControlOp (
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	    __UNCONST("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}
425