| 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 | 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 | __UNCONST("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 | |