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psloop.c

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

/*
 * Copyright (C) 2000 - 2007, R. Byron Moore
 * 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 <acpi/acparser.h>
#include <acpi/acdispat.h>
#include <acpi/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);

/*******************************************************************************
 *
 * 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 %X at AML address %p offset %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.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) {
            /*
             * 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;

      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;
      }

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

      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;

      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);
            }

            /* Special processing for certain opcodes */

            /* TBD (remove): Temporary mechanism to disable this code if needed */

#ifdef ACPI_ENABLE_MODULE_LEVEL_CODE

            if ((walk_state->pass_number <= ACPI_IMODE_LOAD_PASS1) &&
                ((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:

                        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:
                        break;
                  }
            }
#endif

            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_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);

                  if ((*op)->common.aml_opcode != AML_WHILE_OP) {
                        status2 = acpi_ds_result_stack_pop(walk_state);
                        if (ACPI_FAILURE(status2)) {
                              return_ACPI_STATUS(status2);
                        }
                  }
            }

            /* 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);
                        }
                        status2 = acpi_ds_result_stack_pop(walk_state);
                        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;
      }

      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) {
                        /*
                         * 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);
            }

            /* 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);
}

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