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psparse.c

/******************************************************************************
 *
 * Module Name: psparse - Parser top level AML parse routines
 *
 *****************************************************************************/

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

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

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psparse")

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

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

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

      /* Otherwise, just a single byte opcode */

      return (1);
}

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

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

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

      if (opcode == AML_EXTENDED_OP_PREFIX) {

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

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

      return (opcode);
}

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

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

      ACPI_FUNCTION_TRACE_PTR(ps_complete_this_op, op);

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

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

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

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

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

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

                  /* Nothing more to do */

                  goto cleanup;
            }

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

            switch (parent_info->class) {
            case AML_CLASS_CONTROL:
                  break;

            case AML_CLASS_CREATE:

                  /*
                   * These opcodes contain term_arg operands. The current
                   * op must be replaced by a placeholder return op
                   */
                  replacement_op =
                      acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP);
                  if (!replacement_op) {
                        goto allocate_error;
                  }
                  break;

            case AML_CLASS_NAMED_OBJECT:

                  /*
                   * These opcodes contain term_arg operands. The current
                   * op must be replaced by a placeholder return op
                   */
                  if ((op->common.parent->common.aml_opcode ==
                       AML_REGION_OP)
                      || (op->common.parent->common.aml_opcode ==
                        AML_DATA_REGION_OP)
                      || (op->common.parent->common.aml_opcode ==
                        AML_BUFFER_OP)
                      || (op->common.parent->common.aml_opcode ==
                        AML_PACKAGE_OP)
                      || (op->common.parent->common.aml_opcode ==
                        AML_VAR_PACKAGE_OP)) {
                        replacement_op =
                            acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP);
                        if (!replacement_op) {
                              goto allocate_error;
                        }
                  } else
                      if ((op->common.parent->common.aml_opcode ==
                         AML_NAME_OP)
                        && (walk_state->pass_number <=
                            ACPI_IMODE_LOAD_PASS2)) {
                        if ((op->common.aml_opcode == AML_BUFFER_OP)
                            || (op->common.aml_opcode == AML_PACKAGE_OP)
                            || (op->common.aml_opcode ==
                              AML_VAR_PACKAGE_OP)) {
                              replacement_op =
                                  acpi_ps_alloc_op(op->common.
                                               aml_opcode);
                              if (!replacement_op) {
                                    goto allocate_error;
                              }

                              replacement_op->named.data =
                                  op->named.data;
                              replacement_op->named.length =
                                  op->named.length;
                        }
                  }
                  break;

            default:

                  replacement_op =
                      acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP);
                  if (!replacement_op) {
                        goto allocate_error;
                  }
            }

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

            if (prev == op) {

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

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

            /* Search the parent list */

            else
                  while (prev) {

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

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

      cleanup:

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

      acpi_ps_delete_parse_tree(op);
      return_ACPI_STATUS(AE_OK);

      allocate_error:

      /* Always delete the subtree, even on error */

      acpi_ps_delete_parse_tree(op);
      return_ACPI_STATUS(AE_NO_MEMORY);
}

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

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

      ACPI_FUNCTION_TRACE_PTR(ps_next_parse_state, op);

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

      case AE_CTRL_BREAK:

            parser_state->aml = walk_state->aml_last_while;
            walk_state->control_state->common.value = FALSE;
            status = acpi_ds_result_stack_pop(walk_state);
            if (ACPI_SUCCESS(status)) {
                  status = AE_CTRL_BREAK;
            }
            break;

      case AE_CTRL_CONTINUE:

            parser_state->aml = walk_state->aml_last_while;
            status = acpi_ds_result_stack_pop(walk_state);
            if (ACPI_SUCCESS(status)) {
                  status = AE_CTRL_CONTINUE;
            }
            break;

      case AE_CTRL_PENDING:

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

#if 0
      case AE_CTRL_SKIP:

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

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

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

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

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

      case AE_CTRL_TRANSFER:

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

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

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

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

      default:

            status = callback_status;
            if ((callback_status & AE_CODE_MASK) == AE_CODE_CONTROL) {
                  status = AE_OK;
            }
            break;
      }

      return_ACPI_STATUS(status);
}

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

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

      ACPI_FUNCTION_TRACE(ps_parse_aml);

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

      /* Create and initialize a new thread state */

      thread = acpi_ut_create_thread_state();
      if (!thread) {
            acpi_ds_delete_walk_state(walk_state);
            return_ACPI_STATUS(AE_NO_MEMORY);
      }

      walk_state->thread = thread;

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

      acpi_ds_push_walk_state(walk_state, thread);

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

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

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

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

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

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

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

                  ACPI_ERROR_METHOD("Method parse/execution failed",
                                walk_state->method_node, NULL,
                                status);

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

                  if ((status == AE_ALREADY_EXISTS) &&
                      (!walk_state->method_desc->method.mutex)) {
                        ACPI_INFO((AE_INFO,
                                 "Marking method %4.4s as Serialized",
                                 walk_state->method_node->name.
                                 ascii));

                        /*
                         * Method tried to create an object twice. The probable cause is
                         * that the method cannot handle reentrancy.
                         *
                         * The method is marked not_serialized, but it tried to create
                         * a named object, causing the second thread entrance to fail.
                         * Workaround this problem by marking the method permanently
                         * as Serialized.
                         */
                        walk_state->method_desc->method.method_flags |=
                            AML_METHOD_SERIALIZED;
                        walk_state->method_desc->method.sync_level = 0;
                  }
            }

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

            walk_state = acpi_ds_pop_walk_state(thread);

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

            acpi_ds_scope_stack_clear(walk_state);

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

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

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

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

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

            walk_state = acpi_ds_get_current_walk_state(thread);
            if (walk_state) {
                  if (ACPI_SUCCESS(status)) {
                        /*
                         * There is another walk state, restart it.
                         * If the method return value is not used by the parent,
                         * The object is deleted
                         */
                        if (!previous_walk_state->return_desc) {
                              status =
                                  acpi_ds_restart_control_method
                                  (walk_state,
                                   previous_walk_state->
                                   implicit_return_obj);
                        } else {
                              /*
                               * We have a valid return value, delete any implicit
                               * return value.
                               */
                              acpi_ds_clear_implicit_return
                                  (previous_walk_state);

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

                        acpi_ut_remove_reference(previous_walk_state->
                                           return_desc);
                  }
            }

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

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

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

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

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

                        acpi_ut_remove_reference(previous_walk_state->
                                           implicit_return_obj);
                  }
            }

            acpi_ds_delete_walk_state(previous_walk_state);
      }

      /* Normal exit */

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

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