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 71 ACPI_STATUS 72 AcpiDsExecBeginControlOp ( 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 ******************************************************************************/ 173 174 ACPI_STATUS 175 AcpiDsExecEndControlOp ( 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 "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