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 "acpi.h" 46 #include "accommon.h" 47 #include "amlcode.h" 48 #include "acdispat.h" 49 #include "acinterp.h" 50 #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 70 ACPI_STATUS 71 AcpiDsExecBeginControlOp ( 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 ******************************************************************************/ 174 175 ACPI_STATUS 176 AcpiDsExecEndControlOp ( 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 #ifdef ACPI_DEBUGGER 364 AcpiDbSignalBreakPoint (WalkState); 365 366 /* Call to the OSL in case OS wants a piece of the action */ 367 368 Status = AcpiOsSignal (ACPI_SIGNAL_BREAKPOINT, 369 "Executed AML Breakpoint opcode"); 370 #endif 371 break; 372 373 case AML_BREAK_OP: 374 case AML_CONTINUE_OP: /* ACPI 2.0 */ 375 376 /* Pop and delete control states until we find a while */ 377 378 while (WalkState->ControlState && 379 (WalkState->ControlState->Control.Opcode != AML_WHILE_OP)) 380 { 381 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 382 AcpiUtDeleteGenericState (ControlState); 383 } 384 385 /* No while found? */ 386 387 if (!WalkState->ControlState) 388 { 389 return (AE_AML_NO_WHILE); 390 } 391 392 /* Was: WalkState->AmlLastWhile = WalkState->ControlState->Control.AmlPredicateStart; */ 393 394 WalkState->AmlLastWhile = 395 WalkState->ControlState->Control.PackageEnd; 396 397 /* Return status depending on opcode */ 398 399 if (Op->Common.AmlOpcode == AML_BREAK_OP) 400 { 401 Status = AE_CTRL_BREAK; 402 } 403 else 404 { 405 Status = AE_CTRL_CONTINUE; 406 } 407 break; 408 409 default: 410 411 ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p", 412 Op->Common.AmlOpcode, Op)); 413 414 Status = AE_AML_BAD_OPCODE; 415 break; 416 } 417 418 return (Status); 419 } 420