/****************************************************************************** * * Module Name: dscontrol - Support for execution control opcodes - * if/else/while/return * *****************************************************************************/ /* * Copyright (C) 2000 - 2016, Intel Corp. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions, and the following disclaimer, * without modification. * 2. Redistributions in binary form must reproduce at minimum a disclaimer * substantially similar to the "NO WARRANTY" disclaimer below * ("Disclaimer") and any redistribution must be conditioned upon * including a substantially similar Disclaimer requirement for further * binary redistribution. * 3. Neither the names of the above-listed copyright holders nor the names * of any contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * Alternatively, this software may be distributed under the terms of the * GNU General Public License ("GPL") version 2 as published by the Free * Software Foundation. * * NO WARRANTY * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGES. */ #include "acpi.h" #include "accommon.h" #include "amlcode.h" #include "acdispat.h" #include "acinterp.h" #include "acdebug.h" #define _COMPONENT ACPI_DISPATCHER ACPI_MODULE_NAME ("dscontrol") /******************************************************************************* * * FUNCTION: AcpiDsExecBeginControlOp * * PARAMETERS: WalkList - The list that owns the walk stack * Op - The control Op * * RETURN: Status * * DESCRIPTION: Handles all control ops encountered during control method * execution. * ******************************************************************************/ ACPI_STATUS AcpiDsExecBeginControlOp ( ACPI_WALK_STATE *WalkState, ACPI_PARSE_OBJECT *Op) { ACPI_STATUS Status = AE_OK; ACPI_GENERIC_STATE *ControlState; ACPI_FUNCTION_NAME (DsExecBeginControlOp); ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n", Op, Op->Common.AmlOpcode, WalkState)); switch (Op->Common.AmlOpcode) { case AML_WHILE_OP: /* * If this is an additional iteration of a while loop, continue. * There is no need to allocate a new control state. */ if (WalkState->ControlState) { if (WalkState->ControlState->Control.AmlPredicateStart == (WalkState->ParserState.Aml - 1)) { /* Reset the state to start-of-loop */ WalkState->ControlState->Common.State = ACPI_CONTROL_CONDITIONAL_EXECUTING; break; } } /*lint -fallthrough */ case AML_IF_OP: /* * IF/WHILE: Create a new control state to manage these * constructs. We need to manage these as a stack, in order * to handle nesting. */ ControlState = AcpiUtCreateControlState (); if (!ControlState) { Status = AE_NO_MEMORY; break; } /* * Save a pointer to the predicate for multiple executions * of a loop */ ControlState->Control.AmlPredicateStart = WalkState->ParserState.Aml - 1; ControlState->Control.PackageEnd = WalkState->ParserState.PkgEnd; ControlState->Control.Opcode = Op->Common.AmlOpcode; /* Push the control state on this walk's control stack */ AcpiUtPushGenericState (&WalkState->ControlState, ControlState); break; case AML_ELSE_OP: /* Predicate is in the state object */ /* If predicate is true, the IF was executed, ignore ELSE part */ if (WalkState->LastPredicate) { Status = AE_CTRL_TRUE; } break; case AML_RETURN_OP: break; default: break; } return (Status); } /******************************************************************************* * * FUNCTION: AcpiDsExecEndControlOp * * PARAMETERS: WalkList - The list that owns the walk stack * Op - The control Op * * RETURN: Status * * DESCRIPTION: Handles all control ops encountered during control method * execution. * ******************************************************************************/ ACPI_STATUS AcpiDsExecEndControlOp ( ACPI_WALK_STATE *WalkState, ACPI_PARSE_OBJECT *Op) { ACPI_STATUS Status = AE_OK; ACPI_GENERIC_STATE *ControlState; ACPI_FUNCTION_NAME (DsExecEndControlOp); switch (Op->Common.AmlOpcode) { case AML_IF_OP: ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", Op)); /* * Save the result of the predicate in case there is an * ELSE to come */ WalkState->LastPredicate = (BOOLEAN) WalkState->ControlState->Common.Value; /* * Pop the control state that was created at the start * of the IF and free it */ ControlState = AcpiUtPopGenericState (&WalkState->ControlState); AcpiUtDeleteGenericState (ControlState); break; case AML_ELSE_OP: break; case AML_WHILE_OP: ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", Op)); ControlState = WalkState->ControlState; if (ControlState->Common.Value) { /* Predicate was true, the body of the loop was just executed */ /* * This loop counter mechanism allows the interpreter to escape * possibly infinite loops. This can occur in poorly written AML * when the hardware does not respond within a while loop and the * loop does not implement a timeout. */ ControlState->Control.LoopCount++; if (ControlState->Control.LoopCount > AcpiGbl_MaxLoopIterations) { Status = AE_AML_INFINITE_LOOP; break; } /* * Go back and evaluate the predicate and maybe execute the loop * another time */ Status = AE_CTRL_PENDING; WalkState->AmlLastWhile = ControlState->Control.AmlPredicateStart; break; } /* Predicate was false, terminate this while loop */ ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] termination! Op=%p\n",Op)); /* Pop this control state and free it */ ControlState = AcpiUtPopGenericState (&WalkState->ControlState); AcpiUtDeleteGenericState (ControlState); break; case AML_RETURN_OP: ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[RETURN_OP] Op=%p Arg=%p\n",Op, Op->Common.Value.Arg)); /* * One optional operand -- the return value * It can be either an immediate operand or a result that * has been bubbled up the tree */ if (Op->Common.Value.Arg) { /* Since we have a real Return(), delete any implicit return */ AcpiDsClearImplicitReturn (WalkState); /* Return statement has an immediate operand */ Status = AcpiDsCreateOperands (WalkState, Op->Common.Value.Arg); if (ACPI_FAILURE (Status)) { return (Status); } /* * If value being returned is a Reference (such as * an arg or local), resolve it now because it may * cease to exist at the end of the method. */ Status = AcpiExResolveToValue ( &WalkState->Operands [0], WalkState); if (ACPI_FAILURE (Status)) { return (Status); } /* * Get the return value and save as the last result * value. This is the only place where WalkState->ReturnDesc * is set to anything other than zero! */ WalkState->ReturnDesc = WalkState->Operands[0]; } else if (WalkState->ResultCount) { /* Since we have a real Return(), delete any implicit return */ AcpiDsClearImplicitReturn (WalkState); /* * The return value has come from a previous calculation. * * If value being returned is a Reference (such as * an arg or local), resolve it now because it may * cease to exist at the end of the method. * * Allow references created by the Index operator to return * unchanged. */ if ((ACPI_GET_DESCRIPTOR_TYPE (WalkState->Results->Results.ObjDesc[0]) == ACPI_DESC_TYPE_OPERAND) && ((WalkState->Results->Results.ObjDesc [0])->Common.Type == ACPI_TYPE_LOCAL_REFERENCE) && ((WalkState->Results->Results.ObjDesc [0])->Reference.Class != ACPI_REFCLASS_INDEX)) { Status = AcpiExResolveToValue ( &WalkState->Results->Results.ObjDesc [0], WalkState); if (ACPI_FAILURE (Status)) { return (Status); } } WalkState->ReturnDesc = WalkState->Results->Results.ObjDesc [0]; } else { /* No return operand */ if (WalkState->NumOperands) { AcpiUtRemoveReference (WalkState->Operands [0]); } WalkState->Operands[0] = NULL; WalkState->NumOperands = 0; WalkState->ReturnDesc = NULL; } ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Completed RETURN_OP State=%p, RetVal=%p\n", WalkState, WalkState->ReturnDesc)); /* End the control method execution right now */ Status = AE_CTRL_TERMINATE; break; case AML_NOOP_OP: /* Just do nothing! */ break; case AML_BREAK_POINT_OP: #ifdef ACPI_DEBUGGER AcpiDbSignalBreakPoint (WalkState); /* Call to the OSL in case OS wants a piece of the action */ Status = AcpiOsSignal (ACPI_SIGNAL_BREAKPOINT, "Executed AML Breakpoint opcode"); #endif break; case AML_BREAK_OP: case AML_CONTINUE_OP: /* ACPI 2.0 */ /* Pop and delete control states until we find a while */ while (WalkState->ControlState && (WalkState->ControlState->Control.Opcode != AML_WHILE_OP)) { ControlState = AcpiUtPopGenericState (&WalkState->ControlState); AcpiUtDeleteGenericState (ControlState); } /* No while found? */ if (!WalkState->ControlState) { return (AE_AML_NO_WHILE); } /* Was: WalkState->AmlLastWhile = WalkState->ControlState->Control.AmlPredicateStart; */ WalkState->AmlLastWhile = WalkState->ControlState->Control.PackageEnd; /* Return status depending on opcode */ if (Op->Common.AmlOpcode == AML_BREAK_OP) { Status = AE_CTRL_BREAK; } else { Status = AE_CTRL_CONTINUE; } break; default: ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p", Op->Common.AmlOpcode, Op)); Status = AE_AML_BAD_OPCODE; break; } return (Status); }