drivers/acpi/acpica/dscontrol.c

   1 /******************************************************************************
   2  *
   3  * Module Name: dscontrol - Support for execution control opcodes -
   4  *                          if/else/while/return
   5  *
   6  *****************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2017, 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/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  * FUNCTION:    acpi_ds_exec_begin_control_op
  58  *
  59  * PARAMETERS:  walk_list       - The list that owns the walk stack
  60  *              op              - The control Op
  61  *
  62  * RETURN:      Status
  63  *
  64  * DESCRIPTION: Handles all control ops encountered during control method
  65  *              execution.
  66  *
  67  ******************************************************************************/
  68 acpi_status
  69 acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state,
  70                               union acpi_parse_object *op)
  71 {
  72         acpi_status status = AE_OK;
  73         union acpi_generic_state *control_state;
  74
  75         ACPI_FUNCTION_NAME(ds_exec_begin_control_op);
  76
  77         ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n",
  78                           op, op->common.aml_opcode, walk_state));
  79
  80         switch (op->common.aml_opcode) {
  81         case AML_WHILE_OP:
  82                 /*
  83                  * If this is an additional iteration of a while loop, continue.
  84                  * There is no need to allocate a new control state.
  85                  */
  86                 if (walk_state->control_state) {
  87                         if (walk_state->control_state->control.
  88                             aml_predicate_start ==
  89                             (walk_state->parser_state.aml - 1)) {
  90
  91                                 /* Reset the state to start-of-loop */
  92
  93                                 walk_state->control_state->common.state =
  94                                     ACPI_CONTROL_CONDITIONAL_EXECUTING;
  95                                 break;
  96                         }
  97                 }
  98
  99                 /*lint -fallthrough */
 100
 101         case AML_IF_OP:
 102                 /*
 103                  * IF/WHILE: Create a new control state to manage these
 104                  * constructs. We need to manage these as a stack, in order
 105                  * to handle nesting.
 106                  */
 107                 control_state = acpi_ut_create_control_state();
 108                 if (!control_state) {
 109                         status = AE_NO_MEMORY;
 110                         break;
 111                 }
 112                 /*
 113                  * Save a pointer to the predicate for multiple executions
 114                  * of a loop
 115                  */
 116                 control_state->control.aml_predicate_start =
 117                     walk_state->parser_state.aml - 1;
 118                 control_state->control.package_end =
 119                     walk_state->parser_state.pkg_end;
 120                 control_state->control.opcode = op->common.aml_opcode;
 121
 122                 /* Push the control state on this walk's control stack */
 123
 124                 acpi_ut_push_generic_state(&walk_state->control_state,
 125                                            control_state);
 126                 break;
 127
 128         case AML_ELSE_OP:
 129
 130                 /* Predicate is in the state object */
 131                 /* If predicate is true, the IF was executed, ignore ELSE part */
 132
 133                 if (walk_state->last_predicate) {
 134                         status = AE_CTRL_TRUE;
 135                 }
 136
 137                 break;
 138
 139         case AML_RETURN_OP:
 140
 141                 break;
 142
 143         default:
 144
 145                 break;
 146         }
 147
 148         return (status);
 149 }
 150
 151 /*******************************************************************************
 152  *
 153  * FUNCTION:    acpi_ds_exec_end_control_op
 154  *
 155  * PARAMETERS:  walk_list       - The list that owns the walk stack
 156  *              op              - The control Op
 157  *
 158  * RETURN:      Status
 159  *
 160  * DESCRIPTION: Handles all control ops encountered during control method
 161  *              execution.
 162  *
 163  ******************************************************************************/
 164
 165 acpi_status
 166 acpi_ds_exec_end_control_op(struct acpi_walk_state *walk_state,
 167                             union acpi_parse_object *op)
 168 {
 169         acpi_status status = AE_OK;
 170         union acpi_generic_state *control_state;
 171
 172         ACPI_FUNCTION_NAME(ds_exec_end_control_op);
 173
 174         switch (op->common.aml_opcode) {
 175         case AML_IF_OP:
 176
 177                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op));
 178
 179                 /*
 180                  * Save the result of the predicate in case there is an
 181                  * ELSE to come
 182                  */
 183                 walk_state->last_predicate =
 184                     (u8)walk_state->control_state->common.value;
 185
 186                 /*
 187                  * Pop the control state that was created at the start
 188                  * of the IF and free it
 189                  */
 190                 control_state =
 191                     acpi_ut_pop_generic_state(&walk_state->control_state);
 192                 acpi_ut_delete_generic_state(control_state);
 193                 break;
 194
 195         case AML_ELSE_OP:
 196
 197                 break;
 198
 199         case AML_WHILE_OP:
 200
 201                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op));
 202
 203                 control_state = walk_state->control_state;
 204                 if (control_state->common.value) {
 205
 206                         /* Predicate was true, the body of the loop was just executed */
 207
 208                         /*
 209                          * This loop counter mechanism allows the interpreter to escape
 210                          * possibly infinite loops. This can occur in poorly written AML
 211                          * when the hardware does not respond within a while loop and the
 212                          * loop does not implement a timeout.
 213                          */
 214                         control_state->control.loop_count++;
 215                         if (control_state->control.loop_count >
 216                             acpi_gbl_max_loop_iterations) {
 217                                 status = AE_AML_INFINITE_LOOP;
 218                                 break;
 219                         }
 220
 221                         /*
 222                          * Go back and evaluate the predicate and maybe execute the loop
 223                          * another time
 224                          */
 225                         status = AE_CTRL_PENDING;
 226                         walk_state->aml_last_while =
 227                             control_state->control.aml_predicate_start;
 228                         break;
 229                 }
 230
 231                 /* Predicate was false, terminate this while loop */
 232
 233                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 234                                   "[WHILE_OP] termination! Op=%p\n", op));
 235
 236                 /* Pop this control state and free it */
 237
 238                 control_state =
 239                     acpi_ut_pop_generic_state(&walk_state->control_state);
 240                 acpi_ut_delete_generic_state(control_state);
 241                 break;
 242
 243         case AML_RETURN_OP:
 244
 245                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 246                                   "[RETURN_OP] Op=%p Arg=%p\n", op,
 247                                   op->common.value.arg));
 248
 249                 /*
 250                  * One optional operand -- the return value
 251                  * It can be either an immediate operand or a result that
 252                  * has been bubbled up the tree
 253                  */
 254                 if (op->common.value.arg) {
 255
 256                         /* Since we have a real Return(), delete any implicit return */
 257
 258                         acpi_ds_clear_implicit_return(walk_state);
 259
 260                         /* Return statement has an immediate operand */
 261
 262                         status =
 263                             acpi_ds_create_operands(walk_state,
 264                                                     op->common.value.arg);
 265                         if (ACPI_FAILURE(status)) {
 266                                 return (status);
 267                         }
 268
 269                         /*
 270                          * If value being returned is a Reference (such as
 271                          * an arg or local), resolve it now because it may
 272                          * cease to exist at the end of the method.
 273                          */
 274                         status =
 275                             acpi_ex_resolve_to_value(&walk_state->operands[0],
 276                                                      walk_state);
 277                         if (ACPI_FAILURE(status)) {
 278                                 return (status);
 279                         }
 280
 281                         /*
 282                          * Get the return value and save as the last result
 283                          * value. This is the only place where walk_state->return_desc
 284                          * is set to anything other than zero!
 285                          */
 286                         walk_state->return_desc = walk_state->operands[0];
 287                 } else if (walk_state->result_count) {
 288
 289                         /* Since we have a real Return(), delete any implicit return */
 290
 291                         acpi_ds_clear_implicit_return(walk_state);
 292
 293                         /*
 294                          * The return value has come from a previous calculation.
 295                          *
 296                          * If value being returned is a Reference (such as
 297                          * an arg or local), resolve it now because it may
 298                          * cease to exist at the end of the method.
 299                          *
 300                          * Allow references created by the Index operator to return
 301                          * unchanged.
 302                          */
 303                         if ((ACPI_GET_DESCRIPTOR_TYPE
 304                              (walk_state->results->results.obj_desc[0]) ==
 305                              ACPI_DESC_TYPE_OPERAND)
 306                             && ((walk_state->results->results.obj_desc[0])->
 307                                 common.type == ACPI_TYPE_LOCAL_REFERENCE)
 308                             && ((walk_state->results->results.obj_desc[0])->
 309                                 reference.class != ACPI_REFCLASS_INDEX)) {
 310                                 status =
 311                                     acpi_ex_resolve_to_value(&walk_state->
 312                                                              results->results.
 313                                                              obj_desc[0],
 314                                                              walk_state);
 315                                 if (ACPI_FAILURE(status)) {
 316                                         return (status);
 317                                 }
 318                         }
 319
 320                         walk_state->return_desc =
 321                             walk_state->results->results.obj_desc[0];
 322                 } else {
 323                         /* No return operand */
 324
 325                         if (walk_state->num_operands) {
 326                                 acpi_ut_remove_reference(walk_state->
 327                                                          operands[0]);
 328                         }
 329
 330                         walk_state->operands[0] = NULL;
 331                         walk_state->num_operands = 0;
 332                         walk_state->return_desc = NULL;
 333                 }
 334
 335                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 336                                   "Completed RETURN_OP State=%p, RetVal=%p\n",
 337                                   walk_state, walk_state->return_desc));
 338
 339                 /* End the control method execution right now */
 340
 341                 status = AE_CTRL_TERMINATE;
 342                 break;
 343
 344         case AML_NOOP_OP:
 345
 346                 /* Just do nothing! */
 347
 348                 break;
 349
 350         case AML_BREAK_POINT_OP:
 351
 352                 acpi_db_signal_break_point(walk_state);
 353
 354                 /* Call to the OSL in case OS wants a piece of the action */
 355
 356                 status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT,
 357                                         "Executed AML Breakpoint opcode");
 358                 break;
 359
 360         case AML_BREAK_OP:
 361         case AML_CONTINUE_OP:   /* ACPI 2.0 */
 362
 363                 /* Pop and delete control states until we find a while */
 364
 365                 while (walk_state->control_state &&
 366                        (walk_state->control_state->control.opcode !=
 367                         AML_WHILE_OP)) {
 368                         control_state =
 369                             acpi_ut_pop_generic_state(&walk_state->
 370                                                       control_state);
 371                         acpi_ut_delete_generic_state(control_state);
 372                 }
 373
 374                 /* No while found? */
 375
 376                 if (!walk_state->control_state) {
 377                         return (AE_AML_NO_WHILE);
 378                 }
 379
 380                 /* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */
 381
 382                 walk_state->aml_last_while =
 383                     walk_state->control_state->control.package_end;
 384
 385                 /* Return status depending on opcode */
 386
 387                 if (op->common.aml_opcode == AML_BREAK_OP) {
 388                         status = AE_CTRL_BREAK;
 389                 } else {
 390                         status = AE_CTRL_CONTINUE;
 391                 }
 392                 break;
 393
 394         default:
 395
 396                 ACPI_ERROR((AE_INFO, "Unknown control opcode=0x%X Op=%p",
 397                             op->common.aml_opcode, op));
 398
 399                 status = AE_AML_BAD_OPCODE;
 400                 break;
 401         }
 402
 403         return (status);
 404 }