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 - 2018, 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                 control_state->control.loop_timeout = acpi_os_get_timer() +
 122                     (u64)(acpi_gbl_max_loop_iterations * ACPI_100NSEC_PER_SEC);
 123
 124                 /* Push the control state on this walk's control stack */
 125
 126                 acpi_ut_push_generic_state(&walk_state->control_state,
 127                                            control_state);
 128                 break;
 129
 130         case AML_ELSE_OP:
 131
 132                 /* Predicate is in the state object */
 133                 /* If predicate is true, the IF was executed, ignore ELSE part */
 134
 135                 if (walk_state->last_predicate) {
 136                         status = AE_CTRL_TRUE;
 137                 }
 138
 139                 break;
 140
 141         case AML_RETURN_OP:
 142
 143                 break;
 144
 145         default:
 146
 147                 break;
 148         }
 149
 150         return (status);
 151 }
 152
 153 /*******************************************************************************
 154  *
 155  * FUNCTION:    acpi_ds_exec_end_control_op
 156  *
 157  * PARAMETERS:  walk_list       - The list that owns the walk stack
 158  *              op              - The control Op
 159  *
 160  * RETURN:      Status
 161  *
 162  * DESCRIPTION: Handles all control ops encountered during control method
 163  *              execution.
 164  *
 165  ******************************************************************************/
 166
 167 acpi_status
 168 acpi_ds_exec_end_control_op(struct acpi_walk_state *walk_state,
 169                             union acpi_parse_object *op)
 170 {
 171         acpi_status status = AE_OK;
 172         union acpi_generic_state *control_state;
 173
 174         ACPI_FUNCTION_NAME(ds_exec_end_control_op);
 175
 176         switch (op->common.aml_opcode) {
 177         case AML_IF_OP:
 178
 179                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op));
 180
 181                 /*
 182                  * Save the result of the predicate in case there is an
 183                  * ELSE to come
 184                  */
 185                 walk_state->last_predicate =
 186                     (u8)walk_state->control_state->common.value;
 187
 188                 /*
 189                  * Pop the control state that was created at the start
 190                  * of the IF and free it
 191                  */
 192                 control_state =
 193                     acpi_ut_pop_generic_state(&walk_state->control_state);
 194                 acpi_ut_delete_generic_state(control_state);
 195                 break;
 196
 197         case AML_ELSE_OP:
 198
 199                 break;
 200
 201         case AML_WHILE_OP:
 202
 203                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op));
 204
 205                 control_state = walk_state->control_state;
 206                 if (control_state->common.value) {
 207
 208                         /* Predicate was true, the body of the loop was just executed */
 209
 210                         /*
 211                          * This infinite loop detection mechanism allows the interpreter
 212                          * to escape possibly infinite loops. This can occur in poorly
 213                          * written AML when the hardware does not respond within a while
 214                          * loop and the loop does not implement a timeout.
 215                          */
 216                         if (ACPI_TIME_AFTER(acpi_os_get_timer(),
 217                                             control_state->control.
 218                                             loop_timeout)) {
 219                                 status = AE_AML_LOOP_TIMEOUT;
 220                                 break;
 221                         }
 222
 223                         /*
 224                          * Go back and evaluate the predicate and maybe execute the loop
 225                          * another time
 226                          */
 227                         status = AE_CTRL_PENDING;
 228                         walk_state->aml_last_while =
 229                             control_state->control.aml_predicate_start;
 230                         break;
 231                 }
 232
 233                 /* Predicate was false, terminate this while loop */
 234
 235                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 236                                   "[WHILE_OP] termination! Op=%p\n", op));
 237
 238                 /* Pop this control state and free it */
 239
 240                 control_state =
 241                     acpi_ut_pop_generic_state(&walk_state->control_state);
 242                 acpi_ut_delete_generic_state(control_state);
 243                 break;
 244
 245         case AML_RETURN_OP:
 246
 247                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 248                                   "[RETURN_OP] Op=%p Arg=%p\n", op,
 249                                   op->common.value.arg));
 250
 251                 /*
 252                  * One optional operand -- the return value
 253                  * It can be either an immediate operand or a result that
 254                  * has been bubbled up the tree
 255                  */
 256                 if (op->common.value.arg) {
 257
 258                         /* Since we have a real Return(), delete any implicit return */
 259
 260                         acpi_ds_clear_implicit_return(walk_state);
 261
 262                         /* Return statement has an immediate operand */
 263
 264                         status =
 265                             acpi_ds_create_operands(walk_state,
 266                                                     op->common.value.arg);
 267                         if (ACPI_FAILURE(status)) {
 268                                 return (status);
 269                         }
 270
 271                         /*
 272                          * If value being returned is a Reference (such as
 273                          * an arg or local), resolve it now because it may
 274                          * cease to exist at the end of the method.
 275                          */
 276                         status =
 277                             acpi_ex_resolve_to_value(&walk_state->operands[0],
 278                                                      walk_state);
 279                         if (ACPI_FAILURE(status)) {
 280                                 return (status);
 281                         }
 282
 283                         /*
 284                          * Get the return value and save as the last result
 285                          * value. This is the only place where walk_state->return_desc
 286                          * is set to anything other than zero!
 287                          */
 288                         walk_state->return_desc = walk_state->operands[0];
 289                 } else if (walk_state->result_count) {
 290
 291                         /* Since we have a real Return(), delete any implicit return */
 292
 293                         acpi_ds_clear_implicit_return(walk_state);
 294
 295                         /*
 296                          * The return value has come from a previous calculation.
 297                          *
 298                          * If value being returned is a Reference (such as
 299                          * an arg or local), resolve it now because it may
 300                          * cease to exist at the end of the method.
 301                          *
 302                          * Allow references created by the Index operator to return
 303                          * unchanged.
 304                          */
 305                         if ((ACPI_GET_DESCRIPTOR_TYPE
 306                              (walk_state->results->results.obj_desc[0]) ==
 307                              ACPI_DESC_TYPE_OPERAND)
 308                             && ((walk_state->results->results.obj_desc[0])->
 309                                 common.type == ACPI_TYPE_LOCAL_REFERENCE)
 310                             && ((walk_state->results->results.obj_desc[0])->
 311                                 reference.class != ACPI_REFCLASS_INDEX)) {
 312                                 status =
 313                                     acpi_ex_resolve_to_value(&walk_state->
 314                                                              results->results.
 315                                                              obj_desc[0],
 316                                                              walk_state);
 317                                 if (ACPI_FAILURE(status)) {
 318                                         return (status);
 319                                 }
 320                         }
 321
 322                         walk_state->return_desc =
 323                             walk_state->results->results.obj_desc[0];
 324                 } else {
 325                         /* No return operand */
 326
 327                         if (walk_state->num_operands) {
 328                                 acpi_ut_remove_reference(walk_state->
 329                                                          operands[0]);
 330                         }
 331
 332                         walk_state->operands[0] = NULL;
 333                         walk_state->num_operands = 0;
 334                         walk_state->return_desc = NULL;
 335                 }
 336
 337                 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
 338                                   "Completed RETURN_OP State=%p, RetVal=%p\n",
 339                                   walk_state, walk_state->return_desc));
 340
 341                 /* End the control method execution right now */
 342
 343                 status = AE_CTRL_TERMINATE;
 344                 break;
 345
 346         case AML_NOOP_OP:
 347
 348                 /* Just do nothing! */
 349
 350                 break;
 351
 352         case AML_BREAKPOINT_OP:
 353
 354                 acpi_db_signal_break_point(walk_state);
 355
 356                 /* Call to the OSL in case OS wants a piece of the action */
 357
 358                 status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT,
 359                                         "Executed AML Breakpoint opcode");
 360                 break;
 361
 362         case AML_BREAK_OP:
 363         case AML_CONTINUE_OP:   /* ACPI 2.0 */
 364
 365                 /* Pop and delete control states until we find a while */
 366
 367                 while (walk_state->control_state &&
 368                        (walk_state->control_state->control.opcode !=
 369                         AML_WHILE_OP)) {
 370                         control_state =
 371                             acpi_ut_pop_generic_state(&walk_state->
 372                                                       control_state);
 373                         acpi_ut_delete_generic_state(control_state);
 374                 }
 375
 376                 /* No while found? */
 377
 378                 if (!walk_state->control_state) {
 379                         return (AE_AML_NO_WHILE);
 380                 }
 381
 382                 /* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */
 383
 384                 walk_state->aml_last_while =
 385                     walk_state->control_state->control.package_end;
 386
 387                 /* Return status depending on opcode */
 388
 389                 if (op->common.aml_opcode == AML_BREAK_OP) {
 390                         status = AE_CTRL_BREAK;
 391                 } else {
 392                         status = AE_CTRL_CONTINUE;
 393                 }
 394                 break;
 395
 396         default:
 397
 398                 ACPI_ERROR((AE_INFO, "Unknown control opcode=0x%X Op=%p",
 399                             op->common.aml_opcode, op));
 400
 401                 status = AE_AML_BAD_OPCODE;
 402                 break;
 403         }
 404
 405         return (status);
 406 }