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dsmethod.c

/******************************************************************************
 *
 * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
 *
 *****************************************************************************/

/*
 * 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.
 */

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

#define _COMPONENT          ACPI_DISPATCHER
ACPI_MODULE_NAME("dsmethod")

/* Local prototypes */
static acpi_status
acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_method_error
 *
 * PARAMETERS:  Status          - Execution status
 *              walk_state      - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Called on method error. Invoke the global exception handler if
 *              present, dump the method data if the disassembler is configured
 *
 *              Note: Allows the exception handler to change the status code
 *
 ******************************************************************************/

acpi_status
acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
{
      ACPI_FUNCTION_ENTRY();

      /* Ignore AE_OK and control exception codes */

      if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
            return (status);
      }

      /* Invoke the global exception handler */

      if (acpi_gbl_exception_handler) {

            /* Exit the interpreter, allow handler to execute methods */

            acpi_ex_exit_interpreter();

            /*
             * Handler can map the exception code to anything it wants, including
             * AE_OK, in which case the executing method will not be aborted.
             */
            status = acpi_gbl_exception_handler(status,
                                        walk_state->method_node ?
                                        walk_state->method_node->
                                        name.integer : 0,
                                        walk_state->opcode,
                                        walk_state->aml_offset,
                                        NULL);
            (void)acpi_ex_enter_interpreter();
      }
#ifdef ACPI_DISASSEMBLER
      if (ACPI_FAILURE(status)) {

            /* Display method locals/args if disassembler is present */

            acpi_dm_dump_method_info(status, walk_state, walk_state->op);
      }
#endif

      return (status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_method_mutex
 *
 * PARAMETERS:  obj_desc            - The method object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a mutex object for a serialized control method
 *
 ******************************************************************************/

static acpi_status
acpi_ds_create_method_mutex(union acpi_operand_object *method_desc)
{
      union acpi_operand_object *mutex_desc;
      acpi_status status;

      ACPI_FUNCTION_TRACE(ds_create_method_mutex);

      /* Create the new mutex object */

      mutex_desc = acpi_ut_create_internal_object(ACPI_TYPE_MUTEX);
      if (!mutex_desc) {
            return_ACPI_STATUS(AE_NO_MEMORY);
      }

      /* Create the actual OS Mutex */

      status = acpi_os_create_mutex(&mutex_desc->mutex.os_mutex);
      if (ACPI_FAILURE(status)) {
            return_ACPI_STATUS(status);
      }

      mutex_desc->mutex.sync_level = method_desc->method.sync_level;
      method_desc->method.mutex = mutex_desc;
      return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_begin_method_execution
 *
 * PARAMETERS:  method_node         - Node of the method
 *              obj_desc            - The method object
 *              walk_state          - current state, NULL if not yet executing
 *                                    a method.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Prepare a method for execution.  Parses the method if necessary,
 *              increments the thread count, and waits at the method semaphore
 *              for clearance to execute.
 *
 ******************************************************************************/

acpi_status
acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
                         union acpi_operand_object *obj_desc,
                         struct acpi_walk_state *walk_state)
{
      acpi_status status = AE_OK;

      ACPI_FUNCTION_TRACE_PTR(ds_begin_method_execution, method_node);

      if (!method_node) {
            return_ACPI_STATUS(AE_NULL_ENTRY);
      }

      /* Prevent wraparound of thread count */

      if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
            ACPI_ERROR((AE_INFO,
                      "Method reached maximum reentrancy limit (255)"));
            return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
      }

      /*
       * If this method is serialized, we need to acquire the method mutex.
       */
      if (obj_desc->method.method_flags & AML_METHOD_SERIALIZED) {
            /*
             * Create a mutex for the method if it is defined to be Serialized
             * and a mutex has not already been created. We defer the mutex creation
             * until a method is actually executed, to minimize the object count
             */
            if (!obj_desc->method.mutex) {
                  status = acpi_ds_create_method_mutex(obj_desc);
                  if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                  }
            }

            /*
             * The current_sync_level (per-thread) must be less than or equal to
             * the sync level of the method. This mechanism provides some
             * deadlock prevention
             *
             * Top-level method invocation has no walk state at this point
             */
            if (walk_state &&
                (walk_state->thread->current_sync_level >
                 obj_desc->method.mutex->mutex.sync_level)) {
                  ACPI_ERROR((AE_INFO,
                            "Cannot acquire Mutex for method [%4.4s], current SyncLevel is too large (%d)",
                            acpi_ut_get_node_name(method_node),
                            walk_state->thread->current_sync_level));

                  return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
            }

            /*
             * Obtain the method mutex if necessary. Do not acquire mutex for a
             * recursive call.
             */
            if (!walk_state ||
                !obj_desc->method.mutex->mutex.owner_thread ||
                (walk_state->thread !=
                 obj_desc->method.mutex->mutex.owner_thread)) {
                  /*
                   * Acquire the method mutex. This releases the interpreter if we
                   * block (and reacquires it before it returns)
                   */
                  status =
                      acpi_ex_system_wait_mutex(obj_desc->method.mutex->
                                          mutex.os_mutex,
                                          ACPI_WAIT_FOREVER);
                  if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                  }

                  /* Update the mutex and walk info and save the original sync_level */

                  if (walk_state) {
                        obj_desc->method.mutex->mutex.
                            original_sync_level =
                            walk_state->thread->current_sync_level;

                        obj_desc->method.mutex->mutex.owner_thread =
                            walk_state->thread;
                        walk_state->thread->current_sync_level =
                            obj_desc->method.sync_level;
                  } else {
                        obj_desc->method.mutex->mutex.
                            original_sync_level =
                            obj_desc->method.mutex->mutex.sync_level;
                  }
            }

            /* Always increase acquisition depth */

            obj_desc->method.mutex->mutex.acquisition_depth++;
      }

      /*
       * Allocate an Owner ID for this method, only if this is the first thread
       * to begin concurrent execution. We only need one owner_id, even if the
       * method is invoked recursively.
       */
      if (!obj_desc->method.owner_id) {
            status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
            if (ACPI_FAILURE(status)) {
                  goto cleanup;
            }
      }

      /*
       * Increment the method parse tree thread count since it has been
       * reentered one more time (even if it is the same thread)
       */
      obj_desc->method.thread_count++;
      return_ACPI_STATUS(status);

      cleanup:
      /* On error, must release the method mutex (if present) */

      if (obj_desc->method.mutex) {
            acpi_os_release_mutex(obj_desc->method.mutex->mutex.os_mutex);
      }
      return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_call_control_method
 *
 * PARAMETERS:  Thread              - Info for this thread
 *              this_walk_state     - Current walk state
 *              Op                  - Current Op to be walked
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Transfer execution to a called control method
 *
 ******************************************************************************/

acpi_status
acpi_ds_call_control_method(struct acpi_thread_state *thread,
                      struct acpi_walk_state *this_walk_state,
                      union acpi_parse_object *op)
{
      acpi_status status;
      struct acpi_namespace_node *method_node;
      struct acpi_walk_state *next_walk_state = NULL;
      union acpi_operand_object *obj_desc;
      struct acpi_evaluate_info *info;
      u32 i;

      ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);

      ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
                    "Calling method %p, currentstate=%p\n",
                    this_walk_state->prev_op, this_walk_state));

      /*
       * Get the namespace entry for the control method we are about to call
       */
      method_node = this_walk_state->method_call_node;
      if (!method_node) {
            return_ACPI_STATUS(AE_NULL_ENTRY);
      }

      obj_desc = acpi_ns_get_attached_object(method_node);
      if (!obj_desc) {
            return_ACPI_STATUS(AE_NULL_OBJECT);
      }

      /* Init for new method, possibly wait on method mutex */

      status = acpi_ds_begin_method_execution(method_node, obj_desc,
                                    this_walk_state);
      if (ACPI_FAILURE(status)) {
            return_ACPI_STATUS(status);
      }

      /* Begin method parse/execution. Create a new walk state */

      next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
                                        NULL, obj_desc, thread);
      if (!next_walk_state) {
            status = AE_NO_MEMORY;
            goto cleanup;
      }

      /*
       * The resolved arguments were put on the previous walk state's operand
       * stack. Operands on the previous walk state stack always
       * start at index 0. Also, null terminate the list of arguments
       */
      this_walk_state->operands[this_walk_state->num_operands] = NULL;

      /*
       * Allocate and initialize the evaluation information block
       * TBD: this is somewhat inefficient, should change interface to
       * ds_init_aml_walk. For now, keeps this struct off the CPU stack
       */
      info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
      if (!info) {
            return_ACPI_STATUS(AE_NO_MEMORY);
      }

      info->parameters = &this_walk_state->operands[0];
      info->parameter_type = ACPI_PARAM_ARGS;

      status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
                               obj_desc->method.aml_start,
                               obj_desc->method.aml_length, info,
                               ACPI_IMODE_EXECUTE);

      ACPI_FREE(info);
      if (ACPI_FAILURE(status)) {
            goto cleanup;
      }

      /*
       * Delete the operands on the previous walkstate operand stack
       * (they were copied to new objects)
       */
      for (i = 0; i < obj_desc->method.param_count; i++) {
            acpi_ut_remove_reference(this_walk_state->operands[i]);
            this_walk_state->operands[i] = NULL;
      }

      /* Clear the operand stack */

      this_walk_state->num_operands = 0;

      ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
                    "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
                    method_node->name.ascii, next_walk_state));

      /* Invoke an internal method if necessary */

      if (obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY) {
            status = obj_desc->method.implementation(next_walk_state);
      }

      return_ACPI_STATUS(status);

      cleanup:

      /* On error, we must terminate the method properly */

      acpi_ds_terminate_control_method(obj_desc, next_walk_state);
      if (next_walk_state) {
            acpi_ds_delete_walk_state(next_walk_state);
      }

      return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_restart_control_method
 *
 * PARAMETERS:  walk_state          - State for preempted method (caller)
 *              return_desc         - Return value from the called method
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Restart a method that was preempted by another (nested) method
 *              invocation.  Handle the return value (if any) from the callee.
 *
 ******************************************************************************/

acpi_status
acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
                         union acpi_operand_object *return_desc)
{
      acpi_status status;
      int same_as_implicit_return;

      ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);

      ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
                    "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
                    acpi_ut_get_node_name(walk_state->method_node),
                    walk_state->method_call_op, return_desc));

      ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
                    "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
                    walk_state->return_used,
                    walk_state->results, walk_state));

      /* Did the called method return a value? */

      if (return_desc) {

            /* Is the implicit return object the same as the return desc? */

            same_as_implicit_return =
                (walk_state->implicit_return_obj == return_desc);

            /* Are we actually going to use the return value? */

            if (walk_state->return_used) {

                  /* Save the return value from the previous method */

                  status = acpi_ds_result_push(return_desc, walk_state);
                  if (ACPI_FAILURE(status)) {
                        acpi_ut_remove_reference(return_desc);
                        return_ACPI_STATUS(status);
                  }

                  /*
                   * Save as THIS method's return value in case it is returned
                   * immediately to yet another method
                   */
                  walk_state->return_desc = return_desc;
            }

            /*
             * The following code is the optional support for the so-called
             * "implicit return". Some AML code assumes that the last value of the
             * method is "implicitly" returned to the caller, in the absence of an
             * explicit return value.
             *
             * Just save the last result of the method as the return value.
             *
             * NOTE: this is optional because the ASL language does not actually
             * support this behavior.
             */
            else if (!acpi_ds_do_implicit_return
                   (return_desc, walk_state, FALSE)
                   || same_as_implicit_return) {
                  /*
                   * Delete the return value if it will not be used by the
                   * calling method or remove one reference if the explicit return
                   * is the same as the implicit return value.
                   */
                  acpi_ut_remove_reference(return_desc);
            }
      }

      return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_terminate_control_method
 *
 * PARAMETERS:  method_desc         - Method object
 *              walk_state          - State associated with the method
 *
 * RETURN:      None
 *
 * DESCRIPTION: Terminate a control method.  Delete everything that the method
 *              created, delete all locals and arguments, and delete the parse
 *              tree if requested.
 *
 * MUTEX:       Interpreter is locked
 *
 ******************************************************************************/

void
acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
                         struct acpi_walk_state *walk_state)
{
      struct acpi_namespace_node *method_node;
      acpi_status status;

      ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);

      /* method_desc is required, walk_state is optional */

      if (!method_desc) {
            return_VOID;
      }

      if (walk_state) {

            /* Delete all arguments and locals */

            acpi_ds_method_data_delete_all(walk_state);
      }

      /*
       * If method is serialized, release the mutex and restore the
       * current sync level for this thread
       */
      if (method_desc->method.mutex) {

            /* Acquisition Depth handles recursive calls */

            method_desc->method.mutex->mutex.acquisition_depth--;
            if (!method_desc->method.mutex->mutex.acquisition_depth) {
                  walk_state->thread->current_sync_level =
                      method_desc->method.mutex->mutex.
                      original_sync_level;

                  acpi_os_release_mutex(method_desc->method.mutex->mutex.
                                    os_mutex);
                  method_desc->method.mutex->mutex.owner_thread = NULL;
            }
      }

      if (walk_state) {
            /*
             * Delete any objects created by this method during execution.
             * The method Node is stored in the walk state
             */
            method_node = walk_state->method_node;

            /*
             * Delete any namespace objects created anywhere within
             * the namespace by the execution of this method
             */
            acpi_ns_delete_namespace_by_owner(method_desc->method.owner_id);
      }

      /* Decrement the thread count on the method */

      if (method_desc->method.thread_count) {
            method_desc->method.thread_count--;
      } else {
            ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
      }

      /* Are there any other threads currently executing this method? */

      if (method_desc->method.thread_count) {
            /*
             * Additional threads. Do not release the owner_id in this case,
             * we immediately reuse it for the next thread executing this method
             */
            ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
                          "*** Completed execution of one thread, %d threads remaining\n",
                          method_desc->method.thread_count));
      } else {
            /* This is the only executing thread for this method */

            /*
             * Support to dynamically change a method from not_serialized to
             * Serialized if it appears that the method is incorrectly written and
             * does not support multiple thread execution. The best example of this
             * is if such a method creates namespace objects and blocks. A second
             * thread will fail with an AE_ALREADY_EXISTS exception
             *
             * This code is here because we must wait until the last thread exits
             * before creating the synchronization semaphore.
             */
            if ((method_desc->method.method_flags & AML_METHOD_SERIALIZED)
                && (!method_desc->method.mutex)) {
                  status = acpi_ds_create_method_mutex(method_desc);
            }

            /* No more threads, we can free the owner_id */

            acpi_ut_release_owner_id(&method_desc->method.owner_id);
      }

      return_VOID;
}

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