psloop.c

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/******************************************************************************
 *
 * Module Name: psloop - Main AML parse loop
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2012, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

/*
 * 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 "acparser.h"
#include "acdispat.h"
#include "amlcode.h"

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psloop")

static u32 acpi_gbl_depth = 0;

/* Local prototypes */

static acpi_status acpi_ps_get_aml_opcode(struct acpi_walk_state *walk_state);

static acpi_status
acpi_ps_build_named_op(struct acpi_walk_state *walk_state,
               u8 * aml_op_start,
               union acpi_parse_object *unnamed_op,
               union acpi_parse_object **op);

static acpi_status
acpi_ps_create_op(struct acpi_walk_state *walk_state,
          u8 * aml_op_start, union acpi_parse_object **new_op);

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

static acpi_status
acpi_ps_complete_op(struct acpi_walk_state *walk_state,
            union acpi_parse_object **op, acpi_status status);

static acpi_status
acpi_ps_complete_final_op(struct acpi_walk_state *walk_state,
              union acpi_parse_object *op, acpi_status status);

static void
acpi_ps_link_module_code(union acpi_parse_object *parent_op,
             u8 *aml_start, u32 aml_length, acpi_owner_id owner_id);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_aml_opcode
 *
 * PARAMETERS:  walk_state          - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Extract the next AML opcode from the input stream.
 *
 ******************************************************************************/

static acpi_status acpi_ps_get_aml_opcode(struct acpi_walk_state *walk_state)
{

    ACPI_FUNCTION_TRACE_PTR(ps_get_aml_opcode, walk_state);

    walk_state->aml_offset =
        (u32) ACPI_PTR_DIFF(walk_state->parser_state.aml,
                walk_state->parser_state.aml_start);
    walk_state->opcode = acpi_ps_peek_opcode(&(walk_state->parser_state));

    /*
     * First cut to determine what we have found:
     * 1) A valid AML opcode
     * 2) A name string
     * 3) An unknown/invalid opcode
     */
    walk_state->op_info = acpi_ps_get_opcode_info(walk_state->opcode);

    switch (walk_state->op_info->class) {
    case AML_CLASS_ASCII:
    case AML_CLASS_PREFIX:
        /*
         * Starts with a valid prefix or ASCII char, this is a name
         * string. Convert the bare name string to a namepath.
         */
        walk_state->opcode = AML_INT_NAMEPATH_OP;
        walk_state->arg_types = ARGP_NAMESTRING;
        break;

    case AML_CLASS_UNKNOWN:

        /* The opcode is unrecognized. Just skip unknown opcodes */

        ACPI_ERROR((AE_INFO,
                "Found unknown opcode 0x%X at AML address %p offset 0x%X, ignoring",
                walk_state->opcode, walk_state->parser_state.aml,
                walk_state->aml_offset));

        ACPI_DUMP_BUFFER(walk_state->parser_state.aml, 128);

        /* Assume one-byte bad opcode */

        walk_state->parser_state.aml++;
        return_ACPI_STATUS(AE_CTRL_PARSE_CONTINUE);

    default:

        /* Found opcode info, this is a normal opcode */

        walk_state->parser_state.aml +=
            acpi_ps_get_opcode_size(walk_state->opcode);
        walk_state->arg_types = walk_state->op_info->parse_args;
        break;
    }

    return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_build_named_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Begin of named Op in AML
 *              unnamed_op          - Early Op (not a named Op)
 *              op                  - Returned Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse a named Op
 *
 ******************************************************************************/

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

    ACPI_FUNCTION_TRACE_PTR(ps_build_named_op, walk_state);

    unnamed_op->common.value.arg = NULL;
    unnamed_op->common.arg_list_length = 0;
    unnamed_op->common.aml_opcode = walk_state->opcode;

    /*
     * Get and append arguments until we find the node that contains
     * the name (the type ARGP_NAME).
     */
    while (GET_CURRENT_ARG_TYPE(walk_state->arg_types) &&
           (GET_CURRENT_ARG_TYPE(walk_state->arg_types) != ARGP_NAME)) {
        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);
        }

        acpi_ps_append_arg(unnamed_op, arg);
        INCREMENT_ARG_LIST(walk_state->arg_types);
    }

    /*
     * Make sure that we found a NAME and didn't run out of arguments
     */
    if (!GET_CURRENT_ARG_TYPE(walk_state->arg_types)) {
        return_ACPI_STATUS(AE_AML_NO_OPERAND);
    }

    /* We know that this arg is a name, move to next arg */

    INCREMENT_ARG_LIST(walk_state->arg_types);

    /*
     * Find the object. This will either insert the object into
     * the namespace or simply look it up
     */
    walk_state->op = NULL;

    status = walk_state->descending_callback(walk_state, op);
    if (ACPI_FAILURE(status)) {
        ACPI_EXCEPTION((AE_INFO, status, "During name lookup/catalog"));
        return_ACPI_STATUS(status);
    }

    if (!*op) {
        return_ACPI_STATUS(AE_CTRL_PARSE_CONTINUE);
    }

    status = acpi_ps_next_parse_state(walk_state, *op, status);
    if (ACPI_FAILURE(status)) {
        if (status == AE_CTRL_PENDING) {
            return_ACPI_STATUS(AE_CTRL_PARSE_PENDING);
        }
        return_ACPI_STATUS(status);
    }

    acpi_ps_append_arg(*op, unnamed_op->common.value.arg);
    acpi_gbl_depth++;

    if ((*op)->common.aml_opcode == AML_REGION_OP ||
        (*op)->common.aml_opcode == AML_DATA_REGION_OP) {
        /*
         * Defer final parsing of an operation_region body, because we don't
         * have enough info in the first pass to parse it correctly (i.e.,
         * there may be method calls within the term_arg elements of the body.)
         *
         * However, we must continue parsing because the opregion is not a
         * standalone package -- we don't know where the end is at this point.
         *
         * (Length is unknown until parse of the body complete)
         */
        (*op)->named.data = aml_op_start;
        (*op)->named.length = 0;
    }

    return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_create_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Op start in AML
 *              new_op              - Returned Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get Op from AML
 *
 ******************************************************************************/

static acpi_status
acpi_ps_create_op(struct acpi_walk_state *walk_state,
          u8 * aml_op_start, union acpi_parse_object **new_op)
{
    acpi_status status = AE_OK;
    union acpi_parse_object *op;
    union acpi_parse_object *named_op = NULL;
    union acpi_parse_object *parent_scope;
    u8 argument_count;
    const struct acpi_opcode_info *op_info;

    ACPI_FUNCTION_TRACE_PTR(ps_create_op, walk_state);

    status = acpi_ps_get_aml_opcode(walk_state);
    if (status == AE_CTRL_PARSE_CONTINUE) {
        return_ACPI_STATUS(AE_CTRL_PARSE_CONTINUE);
    }

    /* Create Op structure and append to parent's argument list */

    walk_state->op_info = acpi_ps_get_opcode_info(walk_state->opcode);
    op = acpi_ps_alloc_op(walk_state->opcode);
    if (!op) {
        return_ACPI_STATUS(AE_NO_MEMORY);
    }

    if (walk_state->op_info->flags & AML_NAMED) {
        status =
            acpi_ps_build_named_op(walk_state, aml_op_start, op,
                       &named_op);
        acpi_ps_free_op(op);
        if (ACPI_FAILURE(status)) {
            return_ACPI_STATUS(status);
        }

        *new_op = named_op;
        return_ACPI_STATUS(AE_OK);
    }

    /* Not a named opcode, just allocate Op and append to parent */

    if (walk_state->op_info->flags & AML_CREATE) {
        /*
         * Backup to beginning of create_XXXfield declaration
         * body_length is unknown until we parse the body
         */
        op->named.data = aml_op_start;
        op->named.length = 0;
    }

    if (walk_state->opcode == AML_BANK_FIELD_OP) {
        /*
         * Backup to beginning of bank_field declaration
         * body_length is unknown until we parse the body
         */
        op->named.data = aml_op_start;
        op->named.length = 0;
    }

    parent_scope = acpi_ps_get_parent_scope(&(walk_state->parser_state));
    acpi_ps_append_arg(parent_scope, op);

    if (parent_scope) {
        op_info =
            acpi_ps_get_opcode_info(parent_scope->common.aml_opcode);
        if (op_info->flags & AML_HAS_TARGET) {
            argument_count =
                acpi_ps_get_argument_count(op_info->type);
            if (parent_scope->common.arg_list_length >
                argument_count) {
                op->common.flags |= ACPI_PARSEOP_TARGET;
            }
        } else if (parent_scope->common.aml_opcode == AML_INCREMENT_OP) {
            op->common.flags |= ACPI_PARSEOP_TARGET;
        }
    }

    if (walk_state->descending_callback != NULL) {
        /*
         * Find the object. This will either insert the object into
         * the namespace or simply look it up
         */
        walk_state->op = *new_op = op;

        status = walk_state->descending_callback(walk_state, &op);
        status = acpi_ps_next_parse_state(walk_state, op, status);
        if (status == AE_CTRL_PENDING) {
            status = AE_CTRL_PARSE_PENDING;
        }
    }

    return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * 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;
    const struct acpi_opcode_info *op_info;

    ACPI_FUNCTION_TRACE_PTR(ps_get_arguments, walk_state);

    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,
                          1);
        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_offset =
                (u32) ACPI_PTR_DIFF(walk_state->parser_state.aml,
                        walk_state->parser_state.
                        aml_start);

            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) {
                arg->common.aml_offset = walk_state->aml_offset;
                acpi_ps_append_arg(op, arg);
            }

            INCREMENT_ARG_LIST(walk_state->arg_types);
        }

        /*
         * Handle executable code at "module-level". This refers to
         * executable opcodes that appear outside of any control method.
         */
        if ((walk_state->pass_number <= ACPI_IMODE_LOAD_PASS2) &&
            ((walk_state->parse_flags & ACPI_PARSE_DISASSEMBLE) == 0)) {
            /*
             * We want to skip If/Else/While constructs during Pass1 because we
             * want to actually conditionally execute the code during Pass2.
             *
             * Except for disassembly, where we always want to walk the
             * If/Else/While packages
             */
            switch (op->common.aml_opcode) {
            case AML_IF_OP:
            case AML_ELSE_OP:
            case AML_WHILE_OP:

                /*
                 * Currently supported module-level opcodes are:
                 * IF/ELSE/WHILE. These appear to be the most common,
                 * and easiest to support since they open an AML
                 * package.
                 */
                if (walk_state->pass_number ==
                    ACPI_IMODE_LOAD_PASS1) {
                    acpi_ps_link_module_code(op->common.
                                 parent,
                                 aml_op_start,
                                 (u32)
                                 (walk_state->
                                 parser_state.
                                 pkg_end -
                                 aml_op_start),
                                 walk_state->
                                 owner_id);
                }

                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                          "Pass1: Skipping an If/Else/While body\n"));

                /* Skip body of if/else/while in pass 1 */

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

            default:
                /*
                 * Check for an unsupported executable opcode at module
                 * level. We must be in PASS1, the parent must be a SCOPE,
                 * The opcode class must be EXECUTE, and the opcode must
                 * not be an argument to another opcode.
                 */
                if ((walk_state->pass_number ==
                     ACPI_IMODE_LOAD_PASS1)
                    && (op->common.parent->common.aml_opcode ==
                    AML_SCOPE_OP)) {
                    op_info =
                        acpi_ps_get_opcode_info(op->common.
                                    aml_opcode);
                    if ((op_info->class ==
                         AML_CLASS_EXECUTE) && (!arg)) {
                        ACPI_WARNING((AE_INFO,
                                  "Detected an unsupported executable opcode "
                                  "at module-level: [0x%.4X] at table offset 0x%.4X",
                                  op->common.aml_opcode,
                                  (u32)((aml_op_start - walk_state->parser_state.aml_start)
                                + sizeof(struct acpi_table_header))));
                    }
                }
                break;
            }
        }

        /* 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_VAR_PACKAGE_OP:

            if ((op->common.parent) &&
                (op->common.parent->common.aml_opcode ==
                 AML_NAME_OP)
                && (walk_state->pass_number <=
                ACPI_IMODE_LOAD_PASS2)) {
                /*
                 * 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_link_module_code
 *
 * PARAMETERS:  parent_op           - Parent parser op
 *              aml_start           - Pointer to the AML
 *              aml_length          - Length of executable AML
 *              owner_id            - owner_id of module level code
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Wrap the module-level code with a method object and link the
 *              object to the global list. Note, the mutex field of the method
 *              object is used to link multiple module-level code objects.
 *
 ******************************************************************************/

static void
acpi_ps_link_module_code(union acpi_parse_object *parent_op,
             u8 *aml_start, u32 aml_length, acpi_owner_id owner_id)
{
    union acpi_operand_object *prev;
    union acpi_operand_object *next;
    union acpi_operand_object *method_obj;
    struct acpi_namespace_node *parent_node;

    /* Get the tail of the list */

    prev = next = acpi_gbl_module_code_list;
    while (next) {
        prev = next;
        next = next->method.mutex;
    }

    /*
     * Insert the module level code into the list. Merge it if it is
     * adjacent to the previous element.
     */
    if (!prev ||
        ((prev->method.aml_start + prev->method.aml_length) != aml_start)) {

        /* Create, initialize, and link a new temporary method object */

        method_obj = acpi_ut_create_internal_object(ACPI_TYPE_METHOD);
        if (!method_obj) {
            return;
        }

        if (parent_op->common.node) {
            parent_node = parent_op->common.node;
        } else {
            parent_node = acpi_gbl_root_node;
        }

        method_obj->method.aml_start = aml_start;
        method_obj->method.aml_length = aml_length;
        method_obj->method.owner_id = owner_id;
        method_obj->method.info_flags |= ACPI_METHOD_MODULE_LEVEL;

        /*
         * Save the parent node in next_object. This is cheating, but we
         * don't want to expand the method object.
         */
        method_obj->method.next_object =
            ACPI_CAST_PTR(union acpi_operand_object, parent_node);

        if (!prev) {
            acpi_gbl_module_code_list = method_obj;
        } else {
            prev->method.mutex = method_obj;
        }
    } else {
        prev->method.aml_length += aml_length;
    }
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_complete_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              op                  - Returned Op
 *              status              - Parse status before complete Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Complete Op
 *
 ******************************************************************************/

static acpi_status
acpi_ps_complete_op(struct acpi_walk_state *walk_state,
            union acpi_parse_object **op, acpi_status status)
{
    acpi_status status2;

    ACPI_FUNCTION_TRACE_PTR(ps_complete_op, walk_state);

    /*
     * Finished one argument of the containing scope
     */
    walk_state->parser_state.scope->parse_scope.arg_count--;

    /* Close this Op (will result in parse subtree deletion) */

    status2 = acpi_ps_complete_this_op(walk_state, *op);
    if (ACPI_FAILURE(status2)) {
        return_ACPI_STATUS(status2);
    }

    *op = NULL;

    switch (status) {
    case AE_OK:
        break;

    case AE_CTRL_TRANSFER:

        /* We are about to transfer to a called method */

        walk_state->prev_op = NULL;
        walk_state->prev_arg_types = walk_state->arg_types;
        return_ACPI_STATUS(status);

    case AE_CTRL_END:

        acpi_ps_pop_scope(&(walk_state->parser_state), op,
                  &walk_state->arg_types,
                  &walk_state->arg_count);

        if (*op) {
            walk_state->op = *op;
            walk_state->op_info =
                acpi_ps_get_opcode_info((*op)->common.aml_opcode);
            walk_state->opcode = (*op)->common.aml_opcode;

            status = walk_state->ascending_callback(walk_state);
            status =
                acpi_ps_next_parse_state(walk_state, *op, status);

            status2 = acpi_ps_complete_this_op(walk_state, *op);
            if (ACPI_FAILURE(status2)) {
                return_ACPI_STATUS(status2);
            }
        }

        status = AE_OK;
        break;

    case AE_CTRL_BREAK:
    case AE_CTRL_CONTINUE:

        /* Pop off scopes until we find the While */

        while (!(*op) || ((*op)->common.aml_opcode != AML_WHILE_OP)) {
            acpi_ps_pop_scope(&(walk_state->parser_state), op,
                      &walk_state->arg_types,
                      &walk_state->arg_count);
        }

        /* Close this iteration of the While loop */

        walk_state->op = *op;
        walk_state->op_info =
            acpi_ps_get_opcode_info((*op)->common.aml_opcode);
        walk_state->opcode = (*op)->common.aml_opcode;

        status = walk_state->ascending_callback(walk_state);
        status = acpi_ps_next_parse_state(walk_state, *op, status);

        status2 = acpi_ps_complete_this_op(walk_state, *op);
        if (ACPI_FAILURE(status2)) {
            return_ACPI_STATUS(status2);
        }

        status = AE_OK;
        break;

    case AE_CTRL_TERMINATE:

        /* Clean up */
        do {
            if (*op) {
                status2 =
                    acpi_ps_complete_this_op(walk_state, *op);
                if (ACPI_FAILURE(status2)) {
                    return_ACPI_STATUS(status2);
                }

                acpi_ut_delete_generic_state
                    (acpi_ut_pop_generic_state
                     (&walk_state->control_state));
            }

            acpi_ps_pop_scope(&(walk_state->parser_state), op,
                      &walk_state->arg_types,
                      &walk_state->arg_count);

        } while (*op);

        return_ACPI_STATUS(AE_OK);

    default:        /* All other non-AE_OK status */

        do {
            if (*op) {
                status2 =
                    acpi_ps_complete_this_op(walk_state, *op);
                if (ACPI_FAILURE(status2)) {
                    return_ACPI_STATUS(status2);
                }
            }

            acpi_ps_pop_scope(&(walk_state->parser_state), op,
                      &walk_state->arg_types,
                      &walk_state->arg_count);

        } while (*op);

#if 0
        /*
         * TBD: Cleanup parse ops on error
         */
        if (*op == NULL) {
            acpi_ps_pop_scope(parser_state, op,
                      &walk_state->arg_types,
                      &walk_state->arg_count);
        }
#endif
        walk_state->prev_op = NULL;
        walk_state->prev_arg_types = walk_state->arg_types;
        return_ACPI_STATUS(status);
    }

    /* This scope complete? */

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

    ACPI_PREEMPTION_POINT();

    return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_complete_final_op
 *
 * PARAMETERS:  walk_state          - Current state
 *              op                  - Current Op
 *              status              - Current parse status before complete last
 *                                    Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Complete last Op.
 *
 ******************************************************************************/

static acpi_status
acpi_ps_complete_final_op(struct acpi_walk_state *walk_state,
              union acpi_parse_object *op, acpi_status status)
{
    acpi_status status2;

    ACPI_FUNCTION_TRACE_PTR(ps_complete_final_op, walk_state);

    /*
     * Complete the last Op (if not completed), and clear the scope stack.
     * It is easily possible to end an AML "package" with an unbounded number
     * of open scopes (such as when several ASL blocks are closed with
     * sequential closing braces). We want to terminate each one cleanly.
     */
    ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "AML package complete at Op %p\n",
              op));
    do {
        if (op) {
            if (walk_state->ascending_callback != NULL) {
                walk_state->op = op;
                walk_state->op_info =
                    acpi_ps_get_opcode_info(op->common.
                                aml_opcode);
                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 =
                        acpi_ps_complete_op(walk_state, &op,
                                AE_OK);
                    if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                    }
                }

                if (status == AE_CTRL_TERMINATE) {
                    status = AE_OK;

                    /* Clean up */
                    do {
                        if (op) {
                            status2 =
                                acpi_ps_complete_this_op
                                (walk_state, op);
                            if (ACPI_FAILURE
                                (status2)) {
                                return_ACPI_STATUS
                                    (status2);
                            }
                        }

                        acpi_ps_pop_scope(&
                                  (walk_state->
                                   parser_state),
                                  &op,
                                  &walk_state->
                                  arg_types,
                                  &walk_state->
                                  arg_count);

                    } while (op);

                    return_ACPI_STATUS(status);
                }

                else if (ACPI_FAILURE(status)) {

                    /* First error is most important */

                    (void)
                        acpi_ps_complete_this_op(walk_state,
                                     op);
                    return_ACPI_STATUS(status);
                }
            }

            status2 = acpi_ps_complete_this_op(walk_state, op);
            if (ACPI_FAILURE(status2)) {
                return_ACPI_STATUS(status2);
            }
        }

        acpi_ps_pop_scope(&(walk_state->parser_state), &op,
                  &walk_state->arg_types,
                  &walk_state->arg_count);

    } while (op);

    return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * 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;

    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;

#if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (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)
                    && ((status & AE_CODE_MASK) !=
                    AE_CODE_CONTROL)) {
                    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)) {
        aml_op_start = parser_state->aml;
        if (!op) {
            status =
                acpi_ps_create_op(walk_state, aml_op_start, &op);
            if (ACPI_FAILURE(status)) {
                if (status == AE_CTRL_PARSE_CONTINUE) {
                    continue;
                }

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

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

                continue;
            }

            op->common.aml_offset = walk_state->aml_offset;

            if (walk_state->op_info) {
                ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                          "Opcode %4.4X [%s] Op %p Aml %p AmlOffset %5.5X\n",
                          (u32) op->common.aml_opcode,
                          walk_state->op_info->name, op,
                          parser_state->aml,
                          op->common.aml_offset));
            }
        }

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

        /* 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);
                }

                continue;
            }
        }

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

        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 (acpi_gbl_depth) {
                acpi_gbl_depth--;
            }

            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;
            }
        }

        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);
}