// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: psloop - Main AML parse loop
 *
 * Copyright (C) 2000 - 2025, Intel Corp.
 *
 *****************************************************************************/

/*
 * Parse the AML and build an operation tree as most interpreters, (such as
 * Perl) do. Parsing is done by hand rather than with a YACC generated parser
 * to tightly constrain stack and dynamic memory usage. 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 "acinterp.h"
#include "acparser.h"
#include "acdispat.h"
#include "amlcode.h"
#include "acconvert.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psloop")

/* Local prototypes */
static acpi_status
acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
                      u8 * aml_op_start, union acpi_parse_object *op);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_arguments
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Op start in AML
 *              op                  - Current Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get arguments for passed Op.
 *
 ******************************************************************************/

static acpi_status
acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
                      u8 * aml_op_start, union acpi_parse_object *op)
{
        acpi_status status = AE_OK;
        union acpi_parse_object *arg = NULL;

        ACPI_FUNCTION_TRACE_PTR(ps_get_arguments, walk_state);

        ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                          "Get arguments for opcode [%s]\n",
                          op->common.aml_op_name));

        switch (op->common.aml_opcode) {
        case AML_BYTE_OP:       /* AML_BYTEDATA_ARG */
        case AML_WORD_OP:       /* AML_WORDDATA_ARG */
        case AML_DWORD_OP:      /* AML_DWORDATA_ARG */
        case AML_QWORD_OP:      /* AML_QWORDATA_ARG */
        case AML_STRING_OP:     /* AML_ASCIICHARLIST_ARG */

                /* Fill in constant or string argument directly */

                acpi_ps_get_next_simple_arg(&(walk_state->parser_state),
                                            GET_CURRENT_ARG_TYPE(walk_state->
                                                                 arg_types),
                                            op);
                break;

        case AML_INT_NAMEPATH_OP:       /* AML_NAMESTRING_ARG */

                status = acpi_ps_get_next_namepath(walk_state,
                                                   &(walk_state->parser_state),
                                                   op,
                                                   ACPI_POSSIBLE_METHOD_CALL);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

                walk_state->arg_types = 0;
                break;

        default:
                /*
                 * Op is not a constant or string, append each argument to the Op
                 */
                while (GET_CURRENT_ARG_TYPE(walk_state->arg_types) &&
                       !walk_state->arg_count) {
                        walk_state->aml = walk_state->parser_state.aml;

                        switch (op->common.aml_opcode) {
                        case AML_METHOD_OP:
                        case AML_BUFFER_OP:
                        case AML_PACKAGE_OP:
                        case AML_VARIABLE_PACKAGE_OP:
                        case AML_WHILE_OP:

                                break;

                        default:

                                ASL_CV_CAPTURE_COMMENTS(walk_state);
                                break;
                        }

                        status =
                            acpi_ps_get_next_arg(walk_state,
                                                 &(walk_state->parser_state),
                                                 GET_CURRENT_ARG_TYPE
                                                 (walk_state->arg_types), &arg);
                        if (ACPI_FAILURE(status)) {
                                return_ACPI_STATUS(status);
                        }

                        if (arg) {
                                acpi_ps_append_arg(op, arg);
                        }

                        INCREMENT_ARG_LIST(walk_state->arg_types);
                }

                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                  "Final argument count: %8.8X pass %u\n",
                                  walk_state->arg_count,
                                  walk_state->pass_number));

                /* Special processing for certain opcodes */

                switch (op->common.aml_opcode) {
                case AML_METHOD_OP:
                        /*
                         * Skip parsing of control method because we don't have enough
                         * info in the first pass to parse it correctly.
                         *
                         * Save the length and address of the body
                         */
                        op->named.data = walk_state->parser_state.aml;
                        op->named.length = (u32)
                            (walk_state->parser_state.pkg_end -
                             walk_state->parser_state.aml);

                        /* Skip body of method */

                        walk_state->parser_state.aml =
                            walk_state->parser_state.pkg_end;
                        walk_state->arg_count = 0;
                        break;

                case AML_BUFFER_OP:
                case AML_PACKAGE_OP:
                case AML_VARIABLE_PACKAGE_OP:

                        if ((op->common.parent) &&
                            (op->common.parent->common.aml_opcode ==
                             AML_NAME_OP)
                            && (walk_state->pass_number <=
                                ACPI_IMODE_LOAD_PASS2)) {
                                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                                  "Setup Package/Buffer: Pass %u, AML Ptr: %p\n",
                                                  walk_state->pass_number,
                                                  aml_op_start));

                                /*
                                 * Skip parsing of Buffers and Packages because we don't have
                                 * enough info in the first pass to parse them correctly.
                                 */
                                op->named.data = aml_op_start;
                                op->named.length = (u32)
                                    (walk_state->parser_state.pkg_end -
                                     aml_op_start);

                                /* Skip body */

                                walk_state->parser_state.aml =
                                    walk_state->parser_state.pkg_end;
                                walk_state->arg_count = 0;
                        }
                        break;

                case AML_WHILE_OP:

                        if (walk_state->control_state) {
                                walk_state->control_state->control.package_end =
                                    walk_state->parser_state.pkg_end;
                        }
                        break;

                default:

                        /* No action for all other opcodes */

                        break;
                }

                break;
        }

        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_parse_loop
 *
 * PARAMETERS:  walk_state          - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse AML (pointed to by the current parser state) and return
 *              a tree of ops.
 *
 ******************************************************************************/

acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
{
        acpi_status status = AE_OK;
        union acpi_parse_object *op = NULL;     /* current op */
        struct acpi_parse_state *parser_state;
        u8 *aml_op_start = NULL;
        u8 opcode_length;

        ACPI_FUNCTION_TRACE_PTR(ps_parse_loop, walk_state);

        if (walk_state->descending_callback == NULL) {
                return_ACPI_STATUS(AE_BAD_PARAMETER);
        }

        parser_state = &walk_state->parser_state;
        walk_state->arg_types = 0;

#ifndef ACPI_CONSTANT_EVAL_ONLY

        if (walk_state->walk_type & ACPI_WALK_METHOD_RESTART) {

                /* We are restarting a preempted control method */

                if (acpi_ps_has_completed_scope(parser_state)) {
                        /*
                         * We must check if a predicate to an IF or WHILE statement
                         * was just completed
                         */
                        if ((parser_state->scope->parse_scope.op) &&
                            ((parser_state->scope->parse_scope.op->common.
                              aml_opcode == AML_IF_OP)
                             || (parser_state->scope->parse_scope.op->common.
                                 aml_opcode == AML_WHILE_OP))
                            && (walk_state->control_state)
                            && (walk_state->control_state->common.state ==
                                ACPI_CONTROL_PREDICATE_EXECUTING)) {
                                /*
                                 * A predicate was just completed, get the value of the
                                 * predicate and branch based on that value
                                 */
                                walk_state->op = NULL;
                                status =
                                    acpi_ds_get_predicate_value(walk_state,
                                                                ACPI_TO_POINTER
                                                                (TRUE));
                                if (ACPI_FAILURE(status)
                                    && !ACPI_CNTL_EXCEPTION(status)) {
                                        if (status == AE_AML_NO_RETURN_VALUE) {
                                                ACPI_EXCEPTION((AE_INFO, status,
                                                                "Invoked method did not return a value"));
                                        }

                                        ACPI_EXCEPTION((AE_INFO, status,
                                                        "GetPredicate Failed"));
                                        return_ACPI_STATUS(status);
                                }

                                status =
                                    acpi_ps_next_parse_state(walk_state, op,
                                                             status);
                        }

                        acpi_ps_pop_scope(parser_state, &op,
                                          &walk_state->arg_types,
                                          &walk_state->arg_count);
                        ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                          "Popped scope, Op=%p\n", op));
                } else if (walk_state->prev_op) {

                        /* We were in the middle of an op */

                        op = walk_state->prev_op;
                        walk_state->arg_types = walk_state->prev_arg_types;
                }
        }
#endif

        /* Iterative parsing loop, while there is more AML to process: */

        while ((parser_state->aml < parser_state->aml_end) || (op)) {
                ASL_CV_CAPTURE_COMMENTS(walk_state);

                aml_op_start = parser_state->aml;
                if (!op) {
                        status =
                            acpi_ps_create_op(walk_state, aml_op_start, &op);
                        if (ACPI_FAILURE(status)) {
                                /*
                                 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
                                 * executing it as a control method. However, if we encounter
                                 * an error while loading the table, we need to keep trying to
                                 * load the table rather than aborting the table load. Set the
                                 * status to AE_OK to proceed with the table load.
                                 */
                                if ((walk_state->
                                     parse_flags & ACPI_PARSE_MODULE_LEVEL)
                                    && ((status == AE_ALREADY_EXISTS)
                                        || (status == AE_NOT_FOUND))) {
                                        status = AE_OK;
                                }
                                if (status == AE_CTRL_PARSE_CONTINUE) {
                                        continue;
                                }

                                if (status == AE_CTRL_PARSE_PENDING) {
                                        status = AE_OK;
                                }

                                if (status == AE_CTRL_TERMINATE) {
                                        return_ACPI_STATUS(status);
                                }

                                status =
                                    acpi_ps_complete_op(walk_state, &op,
                                                        status);
                                if (ACPI_FAILURE(status)) {
                                        return_ACPI_STATUS(status);
                                }
                                if (acpi_ns_opens_scope
                                    (acpi_ps_get_opcode_info
                                     (walk_state->opcode)->object_type)) {
                                        /*
                                         * If the scope/device op fails to parse, skip the body of
                                         * the scope op because the parse failure indicates that
                                         * the device may not exist.
                                         */
                                        ACPI_INFO(("Skipping parse of AML opcode: %s (0x%4.4X)", acpi_ps_get_opcode_name(walk_state->opcode), walk_state->opcode));

                                        /*
                                         * Determine the opcode length before skipping the opcode.
                                         * An opcode can be 1 byte or 2 bytes in length.
                                         */
                                        opcode_length = 1;
                                        if ((walk_state->opcode & 0xFF00) ==
                                            AML_EXTENDED_OPCODE) {
                                                opcode_length = 2;
                                        }
                                        walk_state->parser_state.aml =
                                            walk_state->aml + opcode_length;

                                        walk_state->parser_state.aml =
                                            acpi_ps_get_next_package_end
                                            (&walk_state->parser_state);
                                        walk_state->aml =
                                            walk_state->parser_state.aml;
                                }

                                continue;
                        }

                        acpi_ex_start_trace_opcode(op, walk_state);
                }

                /*
                 * Start arg_count at zero because we don't know if there are
                 * any args yet
                 */
                walk_state->arg_count = 0;

                switch (op->common.aml_opcode) {
                case AML_BYTE_OP:
                case AML_WORD_OP:
                case AML_DWORD_OP:
                case AML_QWORD_OP:

                        break;

                default:

                        ASL_CV_CAPTURE_COMMENTS(walk_state);
                        break;
                }

                /* Are there any arguments that must be processed? */

                if (walk_state->arg_types) {

                        /* Get arguments */

                        status =
                            acpi_ps_get_arguments(walk_state, aml_op_start, op);
                        if (ACPI_FAILURE(status)) {
                                status =
                                    acpi_ps_complete_op(walk_state, &op,
                                                        status);
                                if (ACPI_FAILURE(status)) {
                                        return_ACPI_STATUS(status);
                                }
                                if ((walk_state->control_state) &&
                                    ((walk_state->control_state->control.
                                      opcode == AML_IF_OP)
                                     || (walk_state->control_state->control.
                                         opcode == AML_WHILE_OP))) {
                                        /*
                                         * If the if/while op fails to parse, we will skip parsing
                                         * the body of the op.
                                         */
                                        parser_state->aml =
                                            walk_state->control_state->control.
                                            aml_predicate_start + 1;
                                        parser_state->aml =
                                            acpi_ps_get_next_package_end
                                            (parser_state);
                                        walk_state->aml = parser_state->aml;

                                        ACPI_ERROR((AE_INFO,
                                                    "Skipping While/If block"));
                                        if (*walk_state->aml == AML_ELSE_OP) {
                                                ACPI_ERROR((AE_INFO,
                                                            "Skipping Else block"));
                                                walk_state->parser_state.aml =
                                                    walk_state->aml + 1;
                                                walk_state->parser_state.aml =
                                                    acpi_ps_get_next_package_end
                                                    (parser_state);
                                                walk_state->aml =
                                                    parser_state->aml;
                                        }
                                        ACPI_FREE(acpi_ut_pop_generic_state
                                                  (&walk_state->control_state));
                                }
                                op = NULL;
                                continue;
                        }
                }

                /* Check for arguments that need to be processed */

                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                                  "Parseloop: argument count: %8.8X\n",
                                  walk_state->arg_count));

                if (walk_state->arg_count) {
                        /*
                         * There are arguments (complex ones), push Op and
                         * prepare for argument
                         */
                        status = acpi_ps_push_scope(parser_state, op,
                                                    walk_state->arg_types,
                                                    walk_state->arg_count);
                        if (ACPI_FAILURE(status)) {
                                status =
                                    acpi_ps_complete_op(walk_state, &op,
                                                        status);
                                if (ACPI_FAILURE(status)) {
                                        return_ACPI_STATUS(status);
                                }

                                continue;
                        }

                        op = NULL;
                        continue;
                }

                /*
                 * All arguments have been processed -- Op is complete,
                 * prepare for next
                 */
                walk_state->op_info =
                    acpi_ps_get_opcode_info(op->common.aml_opcode);
                if (walk_state->op_info->flags & AML_NAMED) {
                        if (op->common.aml_opcode == AML_REGION_OP ||
                            op->common.aml_opcode == AML_DATA_REGION_OP) {
                                /*
                                 * Skip parsing of control method or opregion body,
                                 * because we don't have enough info in the first pass
                                 * to parse them correctly.
                                 *
                                 * Completed parsing an op_region declaration, we now
                                 * know the length.
                                 */
                                op->named.length =
                                    (u32) (parser_state->aml - op->named.data);
                        }
                }

                if (walk_state->op_info->flags & AML_CREATE) {
                        /*
                         * Backup to beginning of create_XXXfield declaration (1 for
                         * Opcode)
                         *
                         * body_length is unknown until we parse the body
                         */
                        op->named.length =
                            (u32) (parser_state->aml - op->named.data);
                }

                if (op->common.aml_opcode == AML_BANK_FIELD_OP) {
                        /*
                         * Backup to beginning of bank_field declaration
                         *
                         * body_length is unknown until we parse the body
                         */
                        op->named.length =
                            (u32) (parser_state->aml - op->named.data);
                }

                /* This op complete, notify the dispatcher */

                if (walk_state->ascending_callback != NULL) {
                        walk_state->op = op;
                        walk_state->opcode = op->common.aml_opcode;

                        status = walk_state->ascending_callback(walk_state);
                        status =
                            acpi_ps_next_parse_state(walk_state, op, status);
                        if (status == AE_CTRL_PENDING) {
                                status = AE_OK;
                        } else
                            if ((walk_state->
                                 parse_flags & ACPI_PARSE_MODULE_LEVEL)
                                && (ACPI_AML_EXCEPTION(status)
                                    || status == AE_ALREADY_EXISTS
                                    || status == AE_NOT_FOUND)) {
                                /*
                                 * ACPI_PARSE_MODULE_LEVEL flag means that we
                                 * are currently loading a table by executing
                                 * it as a control method. However, if we
                                 * encounter an error while loading the table,
                                 * we need to keep trying to load the table
                                 * rather than aborting the table load (setting
                                 * the status to AE_OK continues the table
                                 * load). If we get a failure at this point, it
                                 * means that the dispatcher got an error while
                                 * trying to execute the Op.
                                 */
                                status = AE_OK;
                        }
                }

                status = acpi_ps_complete_op(walk_state, &op, status);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

        }                       /* while parser_state->Aml */

        status = acpi_ps_complete_final_op(walk_state, op, status);
        return_ACPI_STATUS(status);
}