Linux-2.6.12-rc2

[linux-2.6/kvm.git] / drivers / acpi / dispatcher / dsmethod.c

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

/*
 * Copyright (C) 2000 - 2005, 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>


#define _COMPONENT          ACPI_DISPATCHER
         ACPI_MODULE_NAME    ("dsmethod")


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_parse_method
 *
 * PARAMETERS:  obj_handle      - Method node
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Call the parser and parse the AML that is associated with the
 *              method.
 *
 * MUTEX:       Assumes parser is locked
 *
 ******************************************************************************/

acpi_status
acpi_ds_parse_method (
        acpi_handle                     obj_handle)
{
        acpi_status                     status;
        union acpi_operand_object       *obj_desc;
        union acpi_parse_object         *op;
        struct acpi_namespace_node      *node;
        acpi_owner_id                   owner_id;
        struct acpi_walk_state          *walk_state;


        ACPI_FUNCTION_TRACE_PTR ("ds_parse_method", obj_handle);


        /* Parameter Validation */

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

        ACPI_DEBUG_PRINT ((ACPI_DB_PARSE, "**** Parsing [%4.4s] **** named_obj=%p\n",
                acpi_ut_get_node_name (obj_handle), obj_handle));

        /* Extract the method object from the method Node */

        node = (struct acpi_namespace_node *) obj_handle;
        obj_desc = acpi_ns_get_attached_object (node);
        if (!obj_desc) {
                return_ACPI_STATUS (AE_NULL_OBJECT);
        }

        /* Create a mutex for the method if there is a concurrency limit */

        if ((obj_desc->method.concurrency != ACPI_INFINITE_CONCURRENCY) &&
                (!obj_desc->method.semaphore)) {
                status = acpi_os_create_semaphore (obj_desc->method.concurrency,
                                   obj_desc->method.concurrency,
                                   &obj_desc->method.semaphore);
                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }
        }

        /*
         * Allocate a new parser op to be the root of the parsed
         * method tree
         */
        op = acpi_ps_alloc_op (AML_METHOD_OP);
        if (!op) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        /* Init new op with the method name and pointer back to the Node */

        acpi_ps_set_name (op, node->name.integer);
        op->common.node = node;

        /*
         * Get a new owner_id for objects created by this method. Namespace
         * objects (such as Operation Regions) can be created during the
         * first pass parse.
         */
        owner_id = acpi_ut_allocate_owner_id (ACPI_OWNER_TYPE_METHOD);
        obj_desc->method.owning_id = owner_id;

        /* Create and initialize a new walk state */

        walk_state = acpi_ds_create_walk_state (owner_id, NULL, NULL, NULL);
        if (!walk_state) {
                return_ACPI_STATUS (AE_NO_MEMORY);
        }

        status = acpi_ds_init_aml_walk (walk_state, op, node,
                          obj_desc->method.aml_start,
                          obj_desc->method.aml_length, NULL, 1);
        if (ACPI_FAILURE (status)) {
                acpi_ds_delete_walk_state (walk_state);
                return_ACPI_STATUS (status);
        }

        /*
         * Parse the method, first pass
         *
         * The first pass load is where newly declared named objects are
         * added into the namespace.  Actual evaluation of
         * the named objects (what would be called a "second
         * pass") happens during the actual execution of the
         * method so that operands to the named objects can
         * take on dynamic run-time values.
         */
        status = acpi_ps_parse_aml (walk_state);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
                "**** [%4.4s] Parsed **** named_obj=%p Op=%p\n",
                acpi_ut_get_node_name (obj_handle), obj_handle, op));

        acpi_ps_delete_parse_tree (op);
        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_begin_method_execution
 *
 * PARAMETERS:  method_node         - Node of the method
 *              obj_desc            - The method object
 *              calling_method_node - Caller of this method (if non-null)
 *
 * 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_namespace_node      *calling_method_node)
{
        acpi_status                     status = AE_OK;


        ACPI_FUNCTION_TRACE_PTR ("ds_begin_method_execution", method_node);


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

        /*
         * If there is a concurrency limit on this method, we need to
         * obtain a unit from the method semaphore.
         */
        if (obj_desc->method.semaphore) {
                /*
                 * Allow recursive method calls, up to the reentrancy/concurrency
                 * limit imposed by the SERIALIZED rule and the sync_level method
                 * parameter.
                 *
                 * The point of this code is to avoid permanently blocking a
                 * thread that is making recursive method calls.
                 */
                if (method_node == calling_method_node) {
                        if (obj_desc->method.thread_count >= obj_desc->method.concurrency) {
                                return_ACPI_STATUS (AE_AML_METHOD_LIMIT);
                        }
                }

                /*
                 * Get a unit from the method semaphore. This releases the
                 * interpreter if we block
                 */
                status = acpi_ex_system_wait_semaphore (obj_desc->method.semaphore,
                                 ACPI_WAIT_FOREVER);
        }

        /*
         * 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);
}


/*******************************************************************************
 *
 * 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;
        union acpi_operand_object       *obj_desc;
        struct acpi_parameter_info      info;
        u32                             i;


        ACPI_FUNCTION_TRACE_PTR ("ds_call_control_method", this_walk_state);

        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Execute 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);
        }

        obj_desc->method.owning_id = acpi_ut_allocate_owner_id (ACPI_OWNER_TYPE_METHOD);

        /* Init for new method, wait on concurrency semaphore */

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

        if (!(obj_desc->method.method_flags & AML_METHOD_INTERNAL_ONLY)) {
                /* 1) Parse: Create a new walk state for the preempting walk */

                next_walk_state = acpi_ds_create_walk_state (obj_desc->method.owning_id,
                                  op, obj_desc, NULL);
                if (!next_walk_state) {
                        return_ACPI_STATUS (AE_NO_MEMORY);
                }

                /* Create and init a Root Node */

                op = acpi_ps_create_scope_op ();
                if (!op) {
                        status = AE_NO_MEMORY;
                        goto cleanup;
                }

                status = acpi_ds_init_aml_walk (next_walk_state, op, method_node,
                                  obj_desc->method.aml_start, obj_desc->method.aml_length,
                                  NULL, 1);
                if (ACPI_FAILURE (status)) {
                        acpi_ds_delete_walk_state (next_walk_state);
                        goto cleanup;
                }

                /* Begin AML parse */

                status = acpi_ps_parse_aml (next_walk_state);
                acpi_ps_delete_parse_tree (op);
        }

        /* 2) Execute: Create a new state for the preempting walk */

        next_walk_state = acpi_ds_create_walk_state (obj_desc->method.owning_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.
         * Null terminate the list of arguments
         */
        this_walk_state->operands [this_walk_state->num_operands] = NULL;

        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, 3);
        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,
                "Starting nested execution, newstate=%p\n", next_walk_state));

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

        return_ACPI_STATUS (AE_OK);


        /* On error, we must delete the new walk state */

cleanup:
        if (next_walk_state && (next_walk_state->method_desc)) {
                /* Decrement the thread count on the method parse tree */

           next_walk_state->method_desc->method.thread_count--;
        }
        (void) acpi_ds_terminate_control_method (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;


        ACPI_FUNCTION_TRACE_PTR ("ds_restart_control_method", walk_state);


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

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

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

        if (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 a so-called "implicit return". Some AML code
                 * assumes that the last value of the method is "implicitly" returned
                 * to the caller. Just save the last result 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)) {
                        /*
                         * Delete the return value if it will not be used by the
                         * calling method
                         */
                        acpi_ut_remove_reference (return_desc);
                }
        }

        return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_terminate_control_method
 *
 * PARAMETERS:  walk_state          - State of the method
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Terminate a control method.  Delete everything that the method
 *              created, delete all locals and arguments, and delete the parse
 *              tree if requested.
 *
 ******************************************************************************/

acpi_status
acpi_ds_terminate_control_method (
        struct acpi_walk_state          *walk_state)
{
        union acpi_operand_object       *obj_desc;
        struct acpi_namespace_node      *method_node;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE_PTR ("ds_terminate_control_method", walk_state);


        if (!walk_state) {
                return (AE_BAD_PARAMETER);
        }

        /* The current method object was saved in the walk state */

        obj_desc = walk_state->method_desc;
        if (!obj_desc) {
                return_ACPI_STATUS (AE_OK);
        }

        /* Delete all arguments and locals */

        acpi_ds_method_data_delete_all (walk_state);

        /*
         * Lock the parser while we terminate this method.
         * If this is the last thread executing the method,
         * we have additional cleanup to perform
         */
        status = acpi_ut_acquire_mutex (ACPI_MTX_PARSER);
        if (ACPI_FAILURE (status)) {
                return_ACPI_STATUS (status);
        }

        /* Signal completion of the execution of this method if necessary */

        if (walk_state->method_desc->method.semaphore) {
                status = acpi_os_signal_semaphore (
                                  walk_state->method_desc->method.semaphore, 1);
                if (ACPI_FAILURE (status)) {
                        ACPI_REPORT_ERROR (("Could not signal method semaphore\n"));
                        status = AE_OK;

                        /* Ignore error and continue cleanup */
                }
        }

        if (walk_state->method_desc->method.thread_count) {
                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
                        "*** Not deleting method namespace, there are still %d threads\n",
                        walk_state->method_desc->method.thread_count));
        }

        if (!walk_state->method_desc->method.thread_count) {
                /*
                 * Support to dynamically change a method from not_serialized to
                 * Serialized if it appears that the method is written foolishly 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 ((walk_state->method_desc->method.concurrency == 1) &&
                        (!walk_state->method_desc->method.semaphore)) {
                        status = acpi_os_create_semaphore (1,
                                         1,
                                         &walk_state->method_desc->method.semaphore);
                }

                /*
                 * There are no more threads executing this method.  Perform
                 * additional cleanup.
                 *
                 * The method Node is stored in the walk state
                 */
                method_node = walk_state->method_node;

                /*
                 * Delete any namespace entries created immediately underneath
                 * the method
                 */
                status = acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }

                if (method_node->child) {
                        acpi_ns_delete_namespace_subtree (method_node);
                }

                /*
                 * Delete any namespace entries created anywhere else within
                 * the namespace
                 */
                acpi_ns_delete_namespace_by_owner (walk_state->method_desc->method.owning_id);
                status = acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }
        }

        status = acpi_ut_release_mutex (ACPI_MTX_PARSER);
        return_ACPI_STATUS (status);
}