// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
*
* Module Name: dscontrol - Support for execution control opcodes -
* if/else/while/return
*
* Copyright (C) 2000 - 2023, Intel Corp.
*
*****************************************************************************/
#include <acpi/acpi.h>
#include "accommon.h"
#include "amlcode.h"
#include "acdispat.h"
#include "acinterp.h"
#include "acdebug.h"
#define _COMPONENT ACPI_DISPATCHER
ACPI_MODULE_NAME("dscontrol")
/*******************************************************************************
*
* FUNCTION: acpi_ds_exec_begin_control_op
*
* PARAMETERS: walk_list - The list that owns the walk stack
* op - The control Op
*
* RETURN: Status
*
* DESCRIPTION: Handles all control ops encountered during control method
* execution.
*
******************************************************************************/
acpi_status
acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state,
union acpi_parse_object *op)
{
acpi_status status = AE_OK;
union acpi_generic_state *control_state;
ACPI_FUNCTION_NAME(ds_exec_begin_control_op);
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n",
op, op->common.aml_opcode, walk_state));
switch (op->common.aml_opcode) {
case AML_WHILE_OP:
/*
* If this is an additional iteration of a while loop, continue.
* There is no need to allocate a new control state.
*/
if (walk_state->control_state) {
if (walk_state->control_state->control.
aml_predicate_start ==
(walk_state->parser_state.aml - 1)) {
/* Reset the state to start-of-loop */
walk_state->control_state->common.state =
ACPI_CONTROL_CONDITIONAL_EXECUTING;
break;
}
}
ACPI_FALLTHROUGH;
case AML_IF_OP:
/*
* IF/WHILE: Create a new control state to manage these
* constructs. We need to manage these as a stack, in order
* to handle nesting.
*/
control_state = acpi_ut_create_control_state();
if (!control_state) {
status = AE_NO_MEMORY;
break;
}
/*
* Save a pointer to the predicate for multiple executions
* of a loop
*/
control_state->control.aml_predicate_start =
walk_state->parser_state.aml - 1;
control_state->control.package_end =
walk_state->parser_state.pkg_end;
control_state->control.opcode = op->common.aml_opcode;
control_state->control.loop_timeout = acpi_os_get_timer() +
((u64)acpi_gbl_max_loop_iterations * ACPI_100NSEC_PER_SEC);
/* Push the control state on this walk's control stack */
acpi_ut_push_generic_state(&walk_state->control_state,
control_state);
break;
case AML_ELSE_OP:
/* Predicate is in the state object */
/* If predicate is true, the IF was executed, ignore ELSE part */
if (walk_state->last_predicate) {
status = AE_CTRL_TRUE;
}
break;
case AML_RETURN_OP:
break;
default:
break;
}
return (status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ds_exec_end_control_op
*
* PARAMETERS: walk_list - The list that owns the walk stack
* op - The control Op
*
* RETURN: Status
*
* DESCRIPTION: Handles all control ops encountered during control method
* execution.
*
******************************************************************************/
acpi_status
acpi_ds_exec_end_control_op(struct acpi_walk_state *walk_state,
union acpi_parse_object *op)
{
acpi_status status = AE_OK;
union acpi_generic_state *control_state;
ACPI_FUNCTION_NAME(ds_exec_end_control_op);
switch (op->common.aml_opcode) {
case AML_IF_OP:
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", op));
/*
* Save the result of the predicate in case there is an
* ELSE to come
*/
walk_state->last_predicate =
(u8)walk_state->control_state->common.value;
/*
* Pop the control state that was created at the start
* of the IF and free it
*/
control_state =
acpi_ut_pop_generic_state(&walk_state->control_state);
acpi_ut_delete_generic_state(control_state);
break;
case AML_ELSE_OP:
break;
case AML_WHILE_OP:
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", op));
control_state = walk_state->control_state;
if (control_state->common.value) {
/* Predicate was true, the body of the loop was just executed */
/*
* This infinite loop detection mechanism allows the interpreter
* to escape possibly infinite loops. This can occur in poorly
* written AML when the hardware does not respond within a while
* loop and the loop does not implement a timeout.
*/
if (ACPI_TIME_AFTER(acpi_os_get_timer(),
control_state->control.
loop_timeout)) {
status = AE_AML_LOOP_TIMEOUT;
break;
}
/*
* Go back and evaluate the predicate and maybe execute the loop
* another time
*/
status = AE_CTRL_PENDING;
walk_state->aml_last_while =
control_state->control.aml_predicate_start;
break;
}
/* Predicate was false, terminate this while loop */
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
"[WHILE_OP] termination! Op=%p\n", op));
/* Pop this control state and free it */
control_state =
acpi_ut_pop_generic_state(&walk_state->control_state);
acpi_ut_delete_generic_state(control_state);
break;
case AML_RETURN_OP:
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
"[RETURN_OP] Op=%p Arg=%p\n", op,
op->common.value.arg));
/*
* One optional operand -- the return value
* It can be either an immediate operand or a result that
* has been bubbled up the tree
*/
if (op->common.value.arg) {
/* Since we have a real Return(), delete any implicit return */
acpi_ds_clear_implicit_return(walk_state);
/* Return statement has an immediate operand */
status =
acpi_ds_create_operands(walk_state,
op->common.value.arg);
if (ACPI_FAILURE(status)) {
return (status);
}
/*
* If value being returned is a Reference (such as
* an arg or local), resolve it now because it may
* cease to exist at the end of the method.
*/
status =
acpi_ex_resolve_to_value(&walk_state->operands[0],
walk_state);
if (ACPI_FAILURE(status)) {
return (status);
}
/*
* Get the return value and save as the last result
* value. This is the only place where walk_state->return_desc
* is set to anything other than zero!
*/
walk_state->return_desc = walk_state->operands[0];
} else if (walk_state->result_count) {
/* Since we have a real Return(), delete any implicit return */
acpi_ds_clear_implicit_return(walk_state);
/*
* The return value has come from a previous calculation.
*
* If value being returned is a Reference (such as
* an arg or local), resolve it now because it may
* cease to exist at the end of the method.
*
* Allow references created by the Index operator to return
* unchanged.
*/
if ((ACPI_GET_DESCRIPTOR_TYPE
(walk_state->results->results.obj_desc[0]) ==
ACPI_DESC_TYPE_OPERAND)
&& ((walk_state->results->results.obj_desc[0])->
common.type == ACPI_TYPE_LOCAL_REFERENCE)
&& ((walk_state->results->results.obj_desc[0])->
reference.class != ACPI_REFCLASS_INDEX)) {
status =
acpi_ex_resolve_to_value(&walk_state->
results->results.
obj_desc[0],
walk_state);
if (ACPI_FAILURE(status)) {
return (status);
}
}
walk_state->return_desc =
walk_state->results->results.obj_desc[0];
} else {
/* No return operand */
if (walk_state->num_operands) {
acpi_ut_remove_reference(walk_state->
operands[0]);
}
walk_state->operands[0] = NULL;
walk_state->num_operands = 0;
walk_state->return_desc = NULL;
}
ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
"Completed RETURN_OP State=%p, RetVal=%p\n",
walk_state, walk_state->return_desc));
/* End the control method execution right now */
status = AE_CTRL_TERMINATE;
break;
case AML_NOOP_OP:
/* Just do nothing! */
break;
case AML_BREAKPOINT_OP:
acpi_db_signal_break_point(walk_state);
/* Call to the OSL in case OS wants a piece of the action */
status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT,
"Executed AML Breakpoint opcode");
break;
case AML_BREAK_OP:
case AML_CONTINUE_OP: /* ACPI 2.0 */
/* Pop and delete control states until we find a while */
while (walk_state->control_state &&
(walk_state->control_state->control.opcode !=
AML_WHILE_OP)) {
control_state =
acpi_ut_pop_generic_state(&walk_state->
control_state);
acpi_ut_delete_generic_state(control_state);
}
/* No while found? */
if (!walk_state->control_state) {
return (AE_AML_NO_WHILE);
}
/* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */
walk_state->aml_last_while =
walk_state->control_state->control.package_end;
/* Return status depending on opcode */
if (op->common.aml_opcode == AML_BREAK_OP) {
status = AE_CTRL_BREAK;
} else {
status = AE_CTRL_CONTINUE;
}
break;
default:
ACPI_ERROR((AE_INFO, "Unknown control opcode=0x%X Op=%p",
op->common.aml_opcode, op));
status = AE_AML_BAD_OPCODE;
break;
}
return (status);
}
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