1 /****************************************************************************** 2 * 3 * Module Name: dscontrol - Support for execution control opcodes - 4 * if/else/while/return 5 * 6 *****************************************************************************/ 7 8 /* 9 * Copyright (C) 2000 - 2021, 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 MERCHANTABILITY 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 ACPI_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 ControlState->Control.LoopTimeout = AcpiOsGetTimer () + 130 ((UINT64) AcpiGbl_MaxLoopIterations * ACPI_100NSEC_PER_SEC); 131 132 /* Push the control state on this walk's control stack */ 133 134 AcpiUtPushGenericState (&WalkState->ControlState, ControlState); 135 break; 136 137 case AML_ELSE_OP: 138 139 /* Predicate is in the state object */ 140 /* If predicate is true, the IF was executed, ignore ELSE part */ 141 142 if (WalkState->LastPredicate) 143 { 144 Status = AE_CTRL_TRUE; 145 } 146 147 break; 148 149 case AML_RETURN_OP: 150 151 break; 152 153 default: 154 155 break; 156 } 157 158 return (Status); 159 } 160 161 162 /******************************************************************************* 163 * 164 * FUNCTION: AcpiDsExecEndControlOp 165 * 166 * PARAMETERS: WalkList - The list that owns the walk stack 167 * Op - The control Op 168 * 169 * RETURN: Status 170 * 171 * DESCRIPTION: Handles all control ops encountered during control method 172 * execution. 173 * 174 ******************************************************************************/ 175 176 ACPI_STATUS 177 AcpiDsExecEndControlOp ( 178 ACPI_WALK_STATE *WalkState, 179 ACPI_PARSE_OBJECT *Op) 180 { 181 ACPI_STATUS Status = AE_OK; 182 ACPI_GENERIC_STATE *ControlState; 183 184 185 ACPI_FUNCTION_NAME (DsExecEndControlOp); 186 187 188 switch (Op->Common.AmlOpcode) 189 { 190 case AML_IF_OP: 191 192 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", Op)); 193 194 /* 195 * Save the result of the predicate in case there is an 196 * ELSE to come 197 */ 198 WalkState->LastPredicate = 199 (BOOLEAN) WalkState->ControlState->Common.Value; 200 201 /* 202 * Pop the control state that was created at the start 203 * of the IF and free it 204 */ 205 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 206 AcpiUtDeleteGenericState (ControlState); 207 break; 208 209 case AML_ELSE_OP: 210 211 break; 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 infinite loop detection mechanism allows the interpreter 224 * to escape possibly infinite loops. This can occur in poorly 225 * written AML when the hardware does not respond within a while 226 * loop and the loop does not implement a timeout. 227 */ 228 if (ACPI_TIME_AFTER (AcpiOsGetTimer (), 229 ControlState->Control.LoopTimeout)) 230 { 231 Status = AE_AML_LOOP_TIMEOUT; 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 = 241 ControlState->Control.AmlPredicateStart; 242 break; 243 } 244 245 /* Predicate was false, terminate this while loop */ 246 247 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, 248 "[WHILE_OP] termination! Op=%p\n",Op)); 249 250 /* Pop this control state and free it */ 251 252 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 253 AcpiUtDeleteGenericState (ControlState); 254 break; 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 ( 286 &WalkState->Operands [0], WalkState); 287 if (ACPI_FAILURE (Status)) 288 { 289 return (Status); 290 } 291 292 /* 293 * Get the return value and save as the last result 294 * value. This is the only place where WalkState->ReturnDesc 295 * is set to anything other than zero! 296 */ 297 WalkState->ReturnDesc = WalkState->Operands[0]; 298 } 299 else if (WalkState->ResultCount) 300 { 301 /* Since we have a real Return(), delete any implicit return */ 302 303 AcpiDsClearImplicitReturn (WalkState); 304 305 /* 306 * The return value has come from a previous calculation. 307 * 308 * If value being returned is a Reference (such as 309 * an arg or local), resolve it now because it may 310 * cease to exist at the end of the method. 311 * 312 * Allow references created by the Index operator to return 313 * unchanged. 314 */ 315 if ((ACPI_GET_DESCRIPTOR_TYPE (WalkState->Results->Results.ObjDesc[0]) == 316 ACPI_DESC_TYPE_OPERAND) && 317 ((WalkState->Results->Results.ObjDesc [0])->Common.Type == 318 ACPI_TYPE_LOCAL_REFERENCE) && 319 ((WalkState->Results->Results.ObjDesc [0])->Reference.Class != 320 ACPI_REFCLASS_INDEX)) 321 { 322 Status = AcpiExResolveToValue ( 323 &WalkState->Results->Results.ObjDesc [0], WalkState); 324 if (ACPI_FAILURE (Status)) 325 { 326 return (Status); 327 } 328 } 329 330 WalkState->ReturnDesc = WalkState->Results->Results.ObjDesc [0]; 331 } 332 else 333 { 334 /* No return operand */ 335 336 if (WalkState->NumOperands) 337 { 338 AcpiUtRemoveReference (WalkState->Operands [0]); 339 } 340 341 WalkState->Operands[0] = NULL; 342 WalkState->NumOperands = 0; 343 WalkState->ReturnDesc = NULL; 344 } 345 346 347 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, 348 "Completed RETURN_OP State=%p, RetVal=%p\n", 349 WalkState, WalkState->ReturnDesc)); 350 351 /* End the control method execution right now */ 352 353 Status = AE_CTRL_TERMINATE; 354 break; 355 356 case AML_NOOP_OP: 357 358 /* Just do nothing! */ 359 360 break; 361 362 case AML_BREAKPOINT_OP: 363 364 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 break; 371 372 case AML_BREAK_OP: 373 case AML_CONTINUE_OP: /* ACPI 2.0 */ 374 375 /* Pop and delete control states until we find a while */ 376 377 while (WalkState->ControlState && 378 (WalkState->ControlState->Control.Opcode != AML_WHILE_OP)) 379 { 380 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 381 AcpiUtDeleteGenericState (ControlState); 382 } 383 384 /* No while found? */ 385 386 if (!WalkState->ControlState) 387 { 388 return (AE_AML_NO_WHILE); 389 } 390 391 /* Was: WalkState->AmlLastWhile = WalkState->ControlState->Control.AmlPredicateStart; */ 392 393 WalkState->AmlLastWhile = 394 WalkState->ControlState->Control.PackageEnd; 395 396 /* Return status depending on opcode */ 397 398 if (Op->Common.AmlOpcode == AML_BREAK_OP) 399 { 400 Status = AE_CTRL_BREAK; 401 } 402 else 403 { 404 Status = AE_CTRL_CONTINUE; 405 } 406 break; 407 408 default: 409 410 ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p", 411 Op->Common.AmlOpcode, Op)); 412 413 Status = AE_AML_BAD_OPCODE; 414 break; 415 } 416 417 return (Status); 418 } 419