1 /****************************************************************************** 2 * 3 * Module Name: dscontrol - Support for execution control opcodes - 4 * if/else/while/return 5 * 6 *****************************************************************************/ 7 8 /* 9 * Copyright (C) 2000 - 2015, 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 51 #define _COMPONENT ACPI_DISPATCHER 52 ACPI_MODULE_NAME("dscontrol") 53 54 /******************************************************************************* 55 * 56 * FUNCTION: acpi_ds_exec_begin_control_op 57 * 58 * PARAMETERS: walk_list - The list that owns the walk stack 59 * op - The control Op 60 * 61 * RETURN: Status 62 * 63 * DESCRIPTION: Handles all control ops encountered during control method 64 * execution. 65 * 66 ******************************************************************************/ 67 acpi_status 68 acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state, 69 union acpi_parse_object *op) 70 { 71 acpi_status status = AE_OK; 72 union acpi_generic_state *control_state; 73 74 ACPI_FUNCTION_NAME(ds_exec_begin_control_op); 75 76 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n", 77 op, op->common.aml_opcode, walk_state)); 78 79 switch (op->common.aml_opcode) { 80 case AML_WHILE_OP: 81 /* 82 * If this is an additional iteration of a while loop, continue. 83 * There is no need to allocate a new control state. 84 */ 85 if (walk_state->control_state) { 86 if (walk_state->control_state->control. 87 aml_predicate_start == 88 (walk_state->parser_state.aml - 1)) { 89 90 /* Reset the state to start-of-loop */ 91 92 walk_state->control_state->common.state = 93 ACPI_CONTROL_CONDITIONAL_EXECUTING; 94 break; 95 } 96 } 97 98 /*lint -fallthrough */ 99 100 case AML_IF_OP: 101 /* 102 * IF/WHILE: Create a new control state to manage these 103 * constructs. We need to manage these as a stack, in order 104 * to handle nesting. 105 */ 106 control_state = acpi_ut_create_control_state(); 107 if (!control_state) { 108 status = AE_NO_MEMORY; 109 break; 110 } 111 /* 112 * Save a pointer to the predicate for multiple executions 113 * of a loop 114 */ 115 control_state->control.aml_predicate_start = 116 walk_state->parser_state.aml - 1; 117 control_state->control.package_end = 118 walk_state->parser_state.pkg_end; 119 control_state->control.opcode = op->common.aml_opcode; 120 121 /* Push the control state on this walk's control stack */ 122 123 acpi_ut_push_generic_state(&walk_state->control_state, 124 control_state); 125 break; 126 127 case AML_ELSE_OP: 128 129 /* Predicate is in the state object */ 130 /* If predicate is true, the IF was executed, ignore ELSE part */ 131 132 if (walk_state->last_predicate) { 133 status = AE_CTRL_TRUE; 134 } 135 136 break; 137 138 case AML_RETURN_OP: 139 140 break; 141 142 default: 143 144 break; 145 } 146 147 return (status); 148 } 149 150 /******************************************************************************* 151 * 152 * FUNCTION: acpi_ds_exec_end_control_op 153 * 154 * PARAMETERS: walk_list - The list that owns the walk stack 155 * op - The control Op 156 * 157 * RETURN: Status 158 * 159 * DESCRIPTION: Handles all control ops encountered during control method 160 * execution. 161 * 162 ******************************************************************************/ 163 164 acpi_status 165 acpi_ds_exec_end_control_op(struct acpi_walk_state * walk_state, 166 union acpi_parse_object * op) 167 { 168 acpi_status status = AE_OK; 169 union acpi_generic_state *control_state; 170 171 ACPI_FUNCTION_NAME(ds_exec_end_control_op); 172 173 switch (op->common.aml_opcode) { 174 case AML_IF_OP: 175 176 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op)); 177 178 /* 179 * Save the result of the predicate in case there is an 180 * ELSE to come 181 */ 182 walk_state->last_predicate = 183 (u8)walk_state->control_state->common.value; 184 185 /* 186 * Pop the control state that was created at the start 187 * of the IF and free it 188 */ 189 control_state = 190 acpi_ut_pop_generic_state(&walk_state->control_state); 191 acpi_ut_delete_generic_state(control_state); 192 break; 193 194 case AML_ELSE_OP: 195 196 break; 197 198 case AML_WHILE_OP: 199 200 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op)); 201 202 control_state = walk_state->control_state; 203 if (control_state->common.value) { 204 205 /* Predicate was true, the body of the loop was just executed */ 206 207 /* 208 * This loop counter mechanism allows the interpreter to escape 209 * possibly infinite loops. This can occur in poorly written AML 210 * when the hardware does not respond within a while loop and the 211 * loop does not implement a timeout. 212 */ 213 control_state->control.loop_count++; 214 if (control_state->control.loop_count > 215 acpi_gbl_max_loop_iterations) { 216 status = AE_AML_INFINITE_LOOP; 217 break; 218 } 219 220 /* 221 * Go back and evaluate the predicate and maybe execute the loop 222 * another time 223 */ 224 status = AE_CTRL_PENDING; 225 walk_state->aml_last_while = 226 control_state->control.aml_predicate_start; 227 break; 228 } 229 230 /* Predicate was false, terminate this while loop */ 231 232 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, 233 "[WHILE_OP] termination! Op=%p\n", op)); 234 235 /* Pop this control state and free it */ 236 237 control_state = 238 acpi_ut_pop_generic_state(&walk_state->control_state); 239 acpi_ut_delete_generic_state(control_state); 240 break; 241 242 case AML_RETURN_OP: 243 244 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, 245 "[RETURN_OP] Op=%p Arg=%p\n", op, 246 op->common.value.arg)); 247 248 /* 249 * One optional operand -- the return value 250 * It can be either an immediate operand or a result that 251 * has been bubbled up the tree 252 */ 253 if (op->common.value.arg) { 254 255 /* Since we have a real Return(), delete any implicit return */ 256 257 acpi_ds_clear_implicit_return(walk_state); 258 259 /* Return statement has an immediate operand */ 260 261 status = 262 acpi_ds_create_operands(walk_state, 263 op->common.value.arg); 264 if (ACPI_FAILURE(status)) { 265 return (status); 266 } 267 268 /* 269 * If value being returned is a Reference (such as 270 * an arg or local), resolve it now because it may 271 * cease to exist at the end of the method. 272 */ 273 status = 274 acpi_ex_resolve_to_value(&walk_state->operands[0], 275 walk_state); 276 if (ACPI_FAILURE(status)) { 277 return (status); 278 } 279 280 /* 281 * Get the return value and save as the last result 282 * value. This is the only place where walk_state->return_desc 283 * is set to anything other than zero! 284 */ 285 walk_state->return_desc = walk_state->operands[0]; 286 } else if (walk_state->result_count) { 287 288 /* Since we have a real Return(), delete any implicit return */ 289 290 acpi_ds_clear_implicit_return(walk_state); 291 292 /* 293 * The return value has come from a previous calculation. 294 * 295 * If value being returned is a Reference (such as 296 * an arg or local), resolve it now because it may 297 * cease to exist at the end of the method. 298 * 299 * Allow references created by the Index operator to return 300 * unchanged. 301 */ 302 if ((ACPI_GET_DESCRIPTOR_TYPE 303 (walk_state->results->results.obj_desc[0]) == 304 ACPI_DESC_TYPE_OPERAND) 305 && ((walk_state->results->results.obj_desc[0])-> 306 common.type == ACPI_TYPE_LOCAL_REFERENCE) 307 && ((walk_state->results->results.obj_desc[0])-> 308 reference.class != ACPI_REFCLASS_INDEX)) { 309 status = 310 acpi_ex_resolve_to_value(&walk_state-> 311 results->results. 312 obj_desc[0], 313 walk_state); 314 if (ACPI_FAILURE(status)) { 315 return (status); 316 } 317 } 318 319 walk_state->return_desc = 320 walk_state->results->results.obj_desc[0]; 321 } else { 322 /* No return operand */ 323 324 if (walk_state->num_operands) { 325 acpi_ut_remove_reference(walk_state-> 326 operands[0]); 327 } 328 329 walk_state->operands[0] = NULL; 330 walk_state->num_operands = 0; 331 walk_state->return_desc = NULL; 332 } 333 334 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, 335 "Completed RETURN_OP State=%p, RetVal=%p\n", 336 walk_state, walk_state->return_desc)); 337 338 /* End the control method execution right now */ 339 340 status = AE_CTRL_TERMINATE; 341 break; 342 343 case AML_NOOP_OP: 344 345 /* Just do nothing! */ 346 347 break; 348 349 case AML_BREAK_POINT_OP: 350 351 /* 352 * Set the single-step flag. This will cause the debugger (if present) 353 * to break to the console within the AML debugger at the start of the 354 * next AML instruction. 355 */ 356 ACPI_DEBUGGER_EXEC(acpi_gbl_cm_single_step = TRUE); 357 ACPI_DEBUGGER_EXEC(acpi_os_printf 358 ("**break** Executed AML BreakPoint opcode\n")); 359 360 /* Call to the OSL in case OS wants a piece of the action */ 361 362 status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT, 363 "Executed AML Breakpoint opcode"); 364 break; 365 366 case AML_BREAK_OP: 367 case AML_CONTINUE_OP: /* ACPI 2.0 */ 368 369 /* Pop and delete control states until we find a while */ 370 371 while (walk_state->control_state && 372 (walk_state->control_state->control.opcode != 373 AML_WHILE_OP)) { 374 control_state = 375 acpi_ut_pop_generic_state(&walk_state-> 376 control_state); 377 acpi_ut_delete_generic_state(control_state); 378 } 379 380 /* No while found? */ 381 382 if (!walk_state->control_state) { 383 return (AE_AML_NO_WHILE); 384 } 385 386 /* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */ 387 388 walk_state->aml_last_while = 389 walk_state->control_state->control.package_end; 390 391 /* Return status depending on opcode */ 392 393 if (op->common.aml_opcode == AML_BREAK_OP) { 394 status = AE_CTRL_BREAK; 395 } else { 396 status = AE_CTRL_CONTINUE; 397 } 398 break; 399 400 default: 401 402 ACPI_ERROR((AE_INFO, "Unknown control opcode=0x%X Op=%p", 403 op->common.aml_opcode, op)); 404 405 status = AE_AML_BAD_OPCODE; 406 break; 407 } 408 409 return (status); 410 } 411