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 <contrib/dev/acpica/include/acpi.h>
48#include <contrib/dev/acpica/include/accommon.h>
49#include <contrib/dev/acpica/include/amlcode.h>
50#include <contrib/dev/acpica/include/acdispat.h>
51#include <contrib/dev/acpica/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         * 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
173ACPI_STATUS
174AcpiDsExecEndControlOp (
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}
417