// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: psparse - Parser top level AML parse routines
 *
 * Copyright (C) 2000 - 2025, Intel Corp.
 *
 *****************************************************************************/

/*
 * Parse the AML and build an operation tree as most interpreters,
 * like Perl, do. Parsing is done by hand rather than with a YACC
 * generated parser to tightly constrain stack and dynamic memory
 * usage. At the same time, parsing is kept flexible and the code
 * fairly compact by parsing based on a list of AML opcode
 * templates in aml_op_info[]
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acparser.h"
#include "acdispat.h"
#include "amlcode.h"
#include "acinterp.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psparse")

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_opcode_size
 *
 * PARAMETERS:  opcode          - An AML opcode
 *
 * RETURN:      Size of the opcode, in bytes (1 or 2)
 *
 * DESCRIPTION: Get the size of the current opcode.
 *
 ******************************************************************************/
u32 acpi_ps_get_opcode_size(u32 opcode)
{

        /* Extended (2-byte) opcode if > 255 */

        if (opcode > 0x00FF) {
                return (2);
        }

        /* Otherwise, just a single byte opcode */

        return (1);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_peek_opcode
 *
 * PARAMETERS:  parser_state        - A parser state object
 *
 * RETURN:      Next AML opcode
 *
 * DESCRIPTION: Get next AML opcode (without incrementing AML pointer)
 *
 ******************************************************************************/

u16 acpi_ps_peek_opcode(struct acpi_parse_state * parser_state)
{
        u8 *aml;
        u16 opcode;

        aml = parser_state->aml;
        opcode = (u16) ACPI_GET8(aml);

        if (opcode == AML_EXTENDED_PREFIX) {

                /* Extended opcode, get the second opcode byte */

                aml++;
                opcode = (u16) ((opcode << 8) | ACPI_GET8(aml));
        }

        return (opcode);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_complete_this_op
 *
 * PARAMETERS:  walk_state      - Current State
 *              op              - Op to complete
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Perform any cleanup at the completion of an Op.
 *
 ******************************************************************************/

acpi_status
acpi_ps_complete_this_op(struct acpi_walk_state *walk_state,
                         union acpi_parse_object *op)
{
        union acpi_parse_object *prev;
        union acpi_parse_object *next;
        const struct acpi_opcode_info *parent_info;
        union acpi_parse_object *replacement_op = NULL;
        acpi_status status = AE_OK;

        ACPI_FUNCTION_TRACE_PTR(ps_complete_this_op, op);

        /* Check for null Op, can happen if AML code is corrupt */

        if (!op) {
                return_ACPI_STATUS(AE_OK);      /* OK for now */
        }

        acpi_ex_stop_trace_opcode(op, walk_state);

        /* Delete this op and the subtree below it if asked to */

        if (((walk_state->parse_flags & ACPI_PARSE_TREE_MASK) !=
             ACPI_PARSE_DELETE_TREE)
            || (walk_state->op_info->class == AML_CLASS_ARGUMENT)) {
                return_ACPI_STATUS(AE_OK);
        }

        /* Make sure that we only delete this subtree */

        if (op->common.parent) {
                prev = op->common.parent->common.value.arg;
                if (!prev) {

                        /* Nothing more to do */

                        goto cleanup;
                }

                /*
                 * Check if we need to replace the operator and its subtree
                 * with a return value op (placeholder op)
                 */
                parent_info =
                    acpi_ps_get_opcode_info(op->common.parent->common.
                                            aml_opcode);

                switch (parent_info->class) {
                case AML_CLASS_CONTROL:

                        break;

                case AML_CLASS_CREATE:
                        /*
                         * These opcodes contain term_arg operands. The current
                         * op must be replaced by a placeholder return op
                         */
                        replacement_op =
                            acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
                                             op->common.aml);
                        if (!replacement_op) {
                                status = AE_NO_MEMORY;
                        }
                        break;

                case AML_CLASS_NAMED_OBJECT:
                        /*
                         * These opcodes contain term_arg operands. The current
                         * op must be replaced by a placeholder return op
                         */
                        if ((op->common.parent->common.aml_opcode ==
                             AML_REGION_OP)
                            || (op->common.parent->common.aml_opcode ==
                                AML_DATA_REGION_OP)
                            || (op->common.parent->common.aml_opcode ==
                                AML_BUFFER_OP)
                            || (op->common.parent->common.aml_opcode ==
                                AML_PACKAGE_OP)
                            || (op->common.parent->common.aml_opcode ==
                                AML_BANK_FIELD_OP)
                            || (op->common.parent->common.aml_opcode ==
                                AML_VARIABLE_PACKAGE_OP)) {
                                replacement_op =
                                    acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
                                                     op->common.aml);
                                if (!replacement_op) {
                                        status = AE_NO_MEMORY;
                                }
                        } else
                            if ((op->common.parent->common.aml_opcode ==
                                 AML_NAME_OP)
                                && (walk_state->pass_number <=
                                    ACPI_IMODE_LOAD_PASS2)) {
                                if ((op->common.aml_opcode == AML_BUFFER_OP)
                                    || (op->common.aml_opcode == AML_PACKAGE_OP)
                                    || (op->common.aml_opcode ==
                                        AML_VARIABLE_PACKAGE_OP)) {
                                        replacement_op =
                                            acpi_ps_alloc_op(op->common.
                                                             aml_opcode,
                                                             op->common.aml);
                                        if (!replacement_op) {
                                                status = AE_NO_MEMORY;
                                        } else {
                                                replacement_op->named.data =
                                                    op->named.data;
                                                replacement_op->named.length =
                                                    op->named.length;
                                        }
                                }
                        }
                        break;

                default:

                        replacement_op =
                            acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP,
                                             op->common.aml);
                        if (!replacement_op) {
                                status = AE_NO_MEMORY;
                        }
                }

                /* We must unlink this op from the parent tree */

                if (prev == op) {

                        /* This op is the first in the list */

                        if (replacement_op) {
                                replacement_op->common.parent =
                                    op->common.parent;
                                replacement_op->common.value.arg = NULL;
                                replacement_op->common.node = op->common.node;
                                op->common.parent->common.value.arg =
                                    replacement_op;
                                replacement_op->common.next = op->common.next;
                        } else {
                                op->common.parent->common.value.arg =
                                    op->common.next;
                        }
                }

                /* Search the parent list */

                else
                        while (prev) {

                                /* Traverse all siblings in the parent's argument list */

                                next = prev->common.next;
                                if (next == op) {
                                        if (replacement_op) {
                                                replacement_op->common.parent =
                                                    op->common.parent;
                                                replacement_op->common.value.
                                                    arg = NULL;
                                                replacement_op->common.node =
                                                    op->common.node;
                                                prev->common.next =
                                                    replacement_op;
                                                replacement_op->common.next =
                                                    op->common.next;
                                                next = NULL;
                                        } else {
                                                prev->common.next =
                                                    op->common.next;
                                                next = NULL;
                                        }
                                }
                                prev = next;
                        }
        }

cleanup:

        /* Now we can actually delete the subtree rooted at Op */

        acpi_ps_delete_parse_tree(op);
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_next_parse_state
 *
 * PARAMETERS:  walk_state          - Current state
 *              op                  - Current parse op
 *              callback_status     - Status from previous operation
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Update the parser state based upon the return exception from
 *              the parser callback.
 *
 ******************************************************************************/

acpi_status
acpi_ps_next_parse_state(struct acpi_walk_state *walk_state,
                         union acpi_parse_object *op,
                         acpi_status callback_status)
{
        struct acpi_parse_state *parser_state = &walk_state->parser_state;
        acpi_status status = AE_CTRL_PENDING;

        ACPI_FUNCTION_TRACE_PTR(ps_next_parse_state, op);

        switch (callback_status) {
        case AE_CTRL_TERMINATE:
                /*
                 * A control method was terminated via a RETURN statement.
                 * The walk of this method is complete.
                 */
                parser_state->aml = parser_state->aml_end;
                status = AE_CTRL_TERMINATE;
                break;

        case AE_CTRL_BREAK:

                parser_state->aml = walk_state->aml_last_while;
                walk_state->control_state->common.value = FALSE;
                status = AE_CTRL_BREAK;
                break;

        case AE_CTRL_CONTINUE:

                parser_state->aml = walk_state->aml_last_while;
                status = AE_CTRL_CONTINUE;
                break;

        case AE_CTRL_PENDING:

                parser_state->aml = walk_state->aml_last_while;
                break;

#if 0
        case AE_CTRL_SKIP:

                parser_state->aml = parser_state->scope->parse_scope.pkg_end;
                status = AE_OK;
                break;
#endif

        case AE_CTRL_TRUE:
                /*
                 * Predicate of an IF was true, and we are at the matching ELSE.
                 * Just close out this package
                 */
                parser_state->aml = acpi_ps_get_next_package_end(parser_state);
                status = AE_CTRL_PENDING;
                break;

        case AE_CTRL_FALSE:
                /*
                 * Either an IF/WHILE Predicate was false or we encountered a BREAK
                 * opcode. In both cases, we do not execute the rest of the
                 * package;  We simply close out the parent (finishing the walk of
                 * this branch of the tree) and continue execution at the parent
                 * level.
                 */
                parser_state->aml = parser_state->scope->parse_scope.pkg_end;

                /* In the case of a BREAK, just force a predicate (if any) to FALSE */

                walk_state->control_state->common.value = FALSE;
                status = AE_CTRL_END;
                break;

        case AE_CTRL_TRANSFER:

                /* A method call (invocation) -- transfer control */

                status = AE_CTRL_TRANSFER;
                walk_state->prev_op = op;
                walk_state->method_call_op = op;
                walk_state->method_call_node =
                    (op->common.value.arg)->common.node;

                /* Will return value (if any) be used by the caller? */

                walk_state->return_used =
                    acpi_ds_is_result_used(op, walk_state);
                break;

        default:

                status = callback_status;
                if (ACPI_CNTL_EXCEPTION(callback_status)) {
                        status = AE_OK;
                }
                break;
        }

        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_parse_aml
 *
 * PARAMETERS:  walk_state      - Current state
 *
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse raw AML and return a tree of ops
 *
 ******************************************************************************/

acpi_status acpi_ps_parse_aml(struct acpi_walk_state *walk_state)
{
        acpi_status status;
        struct acpi_thread_state *thread;
        struct acpi_thread_state *prev_walk_list = acpi_gbl_current_walk_list;
        struct acpi_walk_state *previous_walk_state;

        ACPI_FUNCTION_TRACE(ps_parse_aml);

        ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                          "Entered with WalkState=%p Aml=%p size=%X\n",
                          walk_state, walk_state->parser_state.aml,
                          walk_state->parser_state.aml_size));

        if (!walk_state->parser_state.aml) {
                return_ACPI_STATUS(AE_BAD_ADDRESS);
        }

        /* Create and initialize a new thread state */

        thread = acpi_ut_create_thread_state();
        if (!thread) {
                if (walk_state->method_desc) {

                        /* Executing a control method - additional cleanup */

                        acpi_ds_terminate_control_method(walk_state->
                                                         method_desc,
                                                         walk_state);
                }

                acpi_ds_delete_walk_state(walk_state);
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        walk_state->thread = thread;

        /*
         * If executing a method, the starting sync_level is this method's
         * sync_level
         */
        if (walk_state->method_desc) {
                walk_state->thread->current_sync_level =
                    walk_state->method_desc->method.sync_level;
        }

        acpi_ds_push_walk_state(walk_state, thread);

        /*
         * This global allows the AML debugger to get a handle to the currently
         * executing control method.
         */
        acpi_gbl_current_walk_list = thread;

        /*
         * Execute the walk loop as long as there is a valid Walk State. This
         * handles nested control method invocations without recursion.
         */
        ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "State=%p\n", walk_state));

        status = AE_OK;
        while (walk_state) {
                if (ACPI_SUCCESS(status)) {
                        /*
                         * The parse_loop executes AML until the method terminates
                         * or calls another method.
                         */
                        status = acpi_ps_parse_loop(walk_state);
                }

                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                  "Completed one call to walk loop, %s State=%p\n",
                                  acpi_format_exception(status), walk_state));

                if (walk_state->method_pathname && walk_state->method_is_nested) {

                        /* Optional object evaluation log */

                        ACPI_DEBUG_PRINT_RAW((ACPI_DB_EVALUATION,
                                              "%-26s:  %*s%s\n",
                                              "   Exit nested method",
                                              (walk_state->
                                               method_nesting_depth + 1) * 3,
                                              " ",
                                              &walk_state->method_pathname[1]));

                        ACPI_FREE(walk_state->method_pathname);
                        walk_state->method_is_nested = FALSE;
                }
                if (status == AE_CTRL_TRANSFER) {
                        /*
                         * A method call was detected.
                         * Transfer control to the called control method
                         */
                        status =
                            acpi_ds_call_control_method(thread, walk_state,
                                                        NULL);
                        if (ACPI_FAILURE(status)) {
                                status =
                                    acpi_ds_method_error(status, walk_state);
                        }

                        /*
                         * If the transfer to the new method method call worked,
                         * a new walk state was created -- get it
                         */
                        walk_state = acpi_ds_get_current_walk_state(thread);
                        continue;
                } else if (status == AE_CTRL_TERMINATE) {
                        status = AE_OK;
                } else if ((status != AE_OK) && (walk_state->method_desc)) {

                        /* Either the method parse or actual execution failed */

                        acpi_ex_exit_interpreter();
                        if (status == AE_ABORT_METHOD) {
                                acpi_ns_print_node_pathname(walk_state->
                                                            method_node,
                                                            "Aborting method");
                                acpi_os_printf("\n");
                        } else {
                                ACPI_ERROR_METHOD("Aborting method",
                                                  walk_state->method_node, NULL,
                                                  status);
                        }
                        acpi_ex_enter_interpreter();

                        /* Check for possible multi-thread reentrancy problem */

                        if ((status == AE_ALREADY_EXISTS) &&
                            (!(walk_state->method_desc->method.info_flags &
                               ACPI_METHOD_SERIALIZED))) {
                                /*
                                 * Method is not serialized and tried to create an object
                                 * twice. The probable cause is that the method cannot
                                 * handle reentrancy. Mark as "pending serialized" now, and
                                 * then mark "serialized" when the last thread exits.
                                 */
                                walk_state->method_desc->method.info_flags |=
                                    ACPI_METHOD_SERIALIZED_PENDING;
                        }
                }

                /* We are done with this walk, move on to the parent if any */

                walk_state = acpi_ds_pop_walk_state(thread);

                /* Reset the current scope to the beginning of scope stack */

                acpi_ds_scope_stack_clear(walk_state);

                /*
                 * If we just returned from the execution of a control method or if we
                 * encountered an error during the method parse phase, there's lots of
                 * cleanup to do
                 */
                if (((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) ==
                     ACPI_PARSE_EXECUTE &&
                     !(walk_state->parse_flags & ACPI_PARSE_MODULE_LEVEL)) ||
                    (ACPI_FAILURE(status))) {
                        acpi_ds_terminate_control_method(walk_state->
                                                         method_desc,
                                                         walk_state);
                }

                /* Delete this walk state and all linked control states */

                acpi_ps_cleanup_scope(&walk_state->parser_state);
                previous_walk_state = walk_state;

                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                  "ReturnValue=%p, ImplicitValue=%p State=%p\n",
                                  walk_state->return_desc,
                                  walk_state->implicit_return_obj, walk_state));

                /* Check if we have restarted a preempted walk */

                walk_state = acpi_ds_get_current_walk_state(thread);
                if (walk_state) {
                        if (ACPI_SUCCESS(status)) {
                                /*
                                 * There is another walk state, restart it.
                                 * If the method return value is not used by the parent,
                                 * The object is deleted
                                 */
                                if (!previous_walk_state->return_desc) {
                                        /*
                                         * In slack mode execution, if there is no return value
                                         * we should implicitly return zero (0) as a default value.
                                         */
                                        if (acpi_gbl_enable_interpreter_slack &&
                                            !previous_walk_state->
                                            implicit_return_obj) {
                                                previous_walk_state->
                                                    implicit_return_obj =
                                                    acpi_ut_create_integer_object
                                                    ((u64) 0);
                                                if (!previous_walk_state->
                                                    implicit_return_obj) {
                                                        return_ACPI_STATUS
                                                            (AE_NO_MEMORY);
                                                }
                                        }

                                        /* Restart the calling control method */

                                        status =
                                            acpi_ds_restart_control_method
                                            (walk_state,
                                             previous_walk_state->
                                             implicit_return_obj);
                                } else {
                                        /*
                                         * We have a valid return value, delete any implicit
                                         * return value.
                                         */
                                        acpi_ds_clear_implicit_return
                                            (previous_walk_state);

                                        status =
                                            acpi_ds_restart_control_method
                                            (walk_state,
                                             previous_walk_state->return_desc);
                                }
                                if (ACPI_SUCCESS(status)) {
                                        walk_state->walk_type |=
                                            ACPI_WALK_METHOD_RESTART;
                                }
                        } else {
                                /* On error, delete any return object or implicit return */

                                acpi_ut_remove_reference(previous_walk_state->
                                                         return_desc);
                                acpi_ds_clear_implicit_return
                                    (previous_walk_state);
                        }
                }

                /*
                 * Just completed a 1st-level method, save the final internal return
                 * value (if any)
                 */
                else if (previous_walk_state->caller_return_desc) {
                        if (previous_walk_state->implicit_return_obj) {
                                *(previous_walk_state->caller_return_desc) =
                                    previous_walk_state->implicit_return_obj;
                        } else {
                                /* NULL if no return value */

                                *(previous_walk_state->caller_return_desc) =
                                    previous_walk_state->return_desc;
                        }
                } else {
                        if (previous_walk_state->return_desc) {

                                /* Caller doesn't want it, must delete it */

                                acpi_ut_remove_reference(previous_walk_state->
                                                         return_desc);
                        }
                        if (previous_walk_state->implicit_return_obj) {

                                /* Caller doesn't want it, must delete it */

                                acpi_ut_remove_reference(previous_walk_state->
                                                         implicit_return_obj);
                        }
                }

                acpi_ds_delete_walk_state(previous_walk_state);
        }

        /* Normal exit */

        acpi_ex_release_all_mutexes(thread);
        acpi_ut_delete_generic_state(ACPI_CAST_PTR
                                     (union acpi_generic_state, thread));
        acpi_gbl_current_walk_list = prev_walk_list;
        return_ACPI_STATUS(status);
}