dscontrol.c revision 306536 
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 <contrib/dev/acpica/include/acpi.h>
46#include <contrib/dev/acpica/include/accommon.h>
47#include <contrib/dev/acpica/include/amlcode.h>
48#include <contrib/dev/acpica/include/acdispat.h>
49#include <contrib/dev/acpica/include/acinterp.h>
50#include <contrib/dev/acpica/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
70ACPI_STATUS
71AcpiDsExecBeginControlOp (
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
175ACPI_STATUS
176AcpiDsExecEndControlOp (
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            "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