xnu-792.1.5.tar.gz

[apple/xnu.git] / osfmk / kern / thread.c

/*
 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_FREE_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */
/*
 *      File:   kern/thread.c
 *      Author: Avadis Tevanian, Jr., Michael Wayne Young, David Golub
 *      Date:   1986
 *
 *      Thread management primitives implementation.
 */
/*
 * Copyright (c) 1993 The University of Utah and
 * the Computer Systems Laboratory (CSL).  All rights reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
 * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
 * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * CSL requests users of this software to return to csl-dist@cs.utah.edu any
 * improvements that they make and grant CSL redistribution rights.
 *
 */

#include <mach_host.h>
#include <mach_prof.h>

#include <mach/mach_types.h>
#include <mach/boolean.h>
#include <mach/policy.h>
#include <mach/thread_info.h>
#include <mach/thread_special_ports.h>
#include <mach/thread_status.h>
#include <mach/time_value.h>
#include <mach/vm_param.h>

#include <machine/thread.h>

#include <kern/kern_types.h>
#include <kern/kalloc.h>
#include <kern/cpu_data.h>
#include <kern/counters.h>
#include <kern/ipc_mig.h>
#include <kern/ipc_tt.h>
#include <kern/mach_param.h>
#include <kern/machine.h>
#include <kern/misc_protos.h>
#include <kern/processor.h>
#include <kern/queue.h>
#include <kern/sched.h>
#include <kern/sched_prim.h>
#include <kern/sync_lock.h>
#include <kern/syscall_subr.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/host.h>
#include <kern/zalloc.h>
#include <kern/profile.h>
#include <kern/assert.h>

#include <ipc/ipc_kmsg.h>
#include <ipc/ipc_port.h>

#include <vm/vm_kern.h>
#include <vm/vm_pageout.h>

#include <sys/kdebug.h>

/*
 * Exported interfaces
 */
#include <mach/task_server.h>
#include <mach/thread_act_server.h>
#include <mach/mach_host_server.h>
#include <mach/host_priv_server.h>

static struct zone                      *thread_zone;

decl_simple_lock_data(static,thread_stack_lock)
static queue_head_t             thread_stack_queue;

decl_simple_lock_data(static,thread_terminate_lock)
static queue_head_t             thread_terminate_queue;

static struct thread    thread_template, init_thread;

#ifdef MACH_BSD
extern void proc_exit(void *);
#endif /* MACH_BSD */

void
thread_bootstrap(void)
{
        /*
         *      Fill in a template thread for fast initialization.
         */

        thread_template.runq = RUN_QUEUE_NULL;

        thread_template.ref_count = 2;

        thread_template.reason = AST_NONE;
        thread_template.at_safe_point = FALSE;
        thread_template.wait_event = NO_EVENT64;
        thread_template.wait_queue = WAIT_QUEUE_NULL;
        thread_template.wait_result = THREAD_WAITING;
        thread_template.options = THREAD_ABORTSAFE;
        thread_template.state = TH_WAIT | TH_UNINT;
        thread_template.wake_active = FALSE;
        thread_template.continuation = THREAD_CONTINUE_NULL;
        thread_template.parameter = NULL;

        thread_template.importance = 0;
        thread_template.sched_mode = 0;
        thread_template.safe_mode = 0;
        thread_template.safe_release = 0;

        thread_template.priority = 0;
        thread_template.sched_pri = 0;
        thread_template.max_priority = 0;
        thread_template.task_priority = 0;
        thread_template.promotions = 0;
        thread_template.pending_promoter_index = 0;
        thread_template.pending_promoter[0] =
                thread_template.pending_promoter[1] = NULL;

        thread_template.realtime.deadline = UINT64_MAX;

        thread_template.current_quantum = 0;

        thread_template.computation_metered = 0;
        thread_template.computation_epoch = 0;

        thread_template.sched_stamp = 0;
        thread_template.sched_usage = 0;
        thread_template.pri_shift = INT8_MAX;
        thread_template.cpu_usage = thread_template.cpu_delta = 0;

        thread_template.bound_processor = PROCESSOR_NULL;
        thread_template.last_processor = PROCESSOR_NULL;
        thread_template.last_switch = 0;

        timer_init(&thread_template.user_timer);
        timer_init(&thread_template.system_timer);
        thread_template.user_timer_save = 0;
        thread_template.system_timer_save = 0;

        thread_template.wait_timer_is_set = FALSE;
        thread_template.wait_timer_active = 0;

        thread_template.depress_timer_active = 0;

        thread_template.processor_set = PROCESSOR_SET_NULL;

        thread_template.special_handler.handler = special_handler;
        thread_template.special_handler.next = 0;

#if     MACH_HOST
        thread_template.may_assign = TRUE;
        thread_template.assign_active = FALSE;
#endif  /* MACH_HOST */
        thread_template.funnel_lock = THR_FUNNEL_NULL;
        thread_template.funnel_state = 0;
        thread_template.recover = (vm_offset_t)NULL;

        init_thread = thread_template;
        machine_set_current_thread(&init_thread);
}

void
thread_init(void)
{
        thread_zone = zinit(
                        sizeof(struct thread),
                        THREAD_MAX * sizeof(struct thread),
                        THREAD_CHUNK * sizeof(struct thread),
                        "threads");

        stack_init();

        /*
         *      Initialize any machine-dependent
         *      per-thread structures necessary.
         */
        machine_thread_init();
}

static void
thread_terminate_continue(void)
{
        panic("thread_terminate_continue");
        /*NOTREACHED*/
}

/*
 *      thread_terminate_self:
 */
void
thread_terminate_self(void)
{
        thread_t                thread = current_thread();
        task_t                  task;
        spl_t                   s;

        s = splsched();
        thread_lock(thread);

        /*
         *      Cancel priority depression, reset scheduling parameters,
         *      and wait for concurrent expirations on other processors.
         */
        if (thread->sched_mode & TH_MODE_ISDEPRESSED) {
                thread->sched_mode &= ~TH_MODE_ISDEPRESSED;

                if (timer_call_cancel(&thread->depress_timer))
                        thread->depress_timer_active--;
        }

        thread_policy_reset(thread);

        while (thread->depress_timer_active > 0) {
                thread_unlock(thread);
                splx(s);

                delay(1);

                s = splsched();
                thread_lock(thread);
        }

        thread_unlock(thread);
        splx(s);

        thread_mtx_lock(thread);

        ulock_release_all(thread);

        ipc_thread_disable(thread);
        
        thread_mtx_unlock(thread);

        /*
         * If we are the last thread to terminate and the task is
         * associated with a BSD process, perform BSD process exit.
         */
        task = thread->task;
        if (    hw_atomic_sub(&task->active_thread_count, 1) == 0       &&
                                        task->bsd_info != NULL                                          )
                proc_exit(task->bsd_info);

        s = splsched();
        thread_lock(thread);

        /*
         *      Cancel wait timer, and wait for
         *      concurrent expirations.
         */
        if (thread->wait_timer_is_set) {
                thread->wait_timer_is_set = FALSE;

                if (timer_call_cancel(&thread->wait_timer))
                        thread->wait_timer_active--;
        }

        while (thread->wait_timer_active > 0) {
                thread_unlock(thread);
                splx(s);

                delay(1);

                s = splsched();
                thread_lock(thread);
        }

        /*
         *      If there is a reserved stack, release it.
         */
        if (thread->reserved_stack != 0) {
                if (thread->reserved_stack != thread->kernel_stack)
                        stack_free_stack(thread->reserved_stack);
                thread->reserved_stack = 0;
        }

        /*
         *      Mark thread as terminating, and block.
         */
        thread->state |= TH_TERMINATE;
        thread_mark_wait_locked(thread, THREAD_UNINT);
        assert(thread->promotions == 0);
        thread_unlock(thread);
        /* splsched */

        thread_block((thread_continue_t)thread_terminate_continue);
        /*NOTREACHED*/
}

void
thread_deallocate(
        thread_t                        thread)
{
        processor_set_t         pset;
        task_t                          task;

        if (thread == THREAD_NULL)
                return;

        if (thread_deallocate_internal(thread) > 0)
                return;

        ipc_thread_terminate(thread);

        task = thread->task;

#ifdef MACH_BSD 
        {
                void *ut = thread->uthread;

                thread->uthread = NULL;
                uthread_free(task, ut, task->bsd_info);
        }
#endif  /* MACH_BSD */   

        task_deallocate(task);

        pset = thread->processor_set;
        pset_deallocate(pset);

        if (thread->kernel_stack != 0)
                stack_free(thread);

        machine_thread_destroy(thread);

        zfree(thread_zone, thread);
}

/*
 *      thread_terminate_daemon:
 *
 *      Perform final clean up for terminating threads.
 */
static void
thread_terminate_daemon(void)
{
        thread_t                        thread;
        task_t                          task;
        processor_set_t         pset;

        (void)splsched();
        simple_lock(&thread_terminate_lock);

        while ((thread = (thread_t)dequeue_head(&thread_terminate_queue)) != THREAD_NULL) {
                simple_unlock(&thread_terminate_lock);
                (void)spllo();

                task = thread->task;

                task_lock(task);
                task->total_user_time += timer_grab(&thread->user_timer);
                task->total_system_time += timer_grab(&thread->system_timer);

                queue_remove(&task->threads, thread, thread_t, task_threads);
                task->thread_count--;
                task_unlock(task);

                pset = thread->processor_set;

                pset_lock(pset);
                pset_remove_thread(pset, thread);
                pset_unlock(pset);

                thread_deallocate(thread);

                (void)splsched();
                simple_lock(&thread_terminate_lock);
        }

        assert_wait((event_t)&thread_terminate_queue, THREAD_UNINT);
        simple_unlock(&thread_terminate_lock);
        /* splsched */

        thread_block((thread_continue_t)thread_terminate_daemon);
        /*NOTREACHED*/
}

/*
 *      thread_terminate_enqueue:
 *
 *      Enqueue a terminating thread for final disposition.
 *
 *      Called at splsched.
 */
void
thread_terminate_enqueue(
        thread_t                thread)
{
        simple_lock(&thread_terminate_lock);
        enqueue_tail(&thread_terminate_queue, (queue_entry_t)thread);
        simple_unlock(&thread_terminate_lock);

        thread_wakeup((event_t)&thread_terminate_queue);
}

/*
 *      thread_stack_daemon:
 *
 *      Perform stack allocation as required due to
 *      invoke failures.
 */
static void
thread_stack_daemon(void)
{
        thread_t                thread;

        (void)splsched();
        simple_lock(&thread_stack_lock);

        while ((thread = (thread_t)dequeue_head(&thread_stack_queue)) != THREAD_NULL) {
                simple_unlock(&thread_stack_lock);
                /* splsched */

                stack_alloc(thread);

                thread_lock(thread);
                thread_setrun(thread, SCHED_PREEMPT | SCHED_TAILQ);
                thread_unlock(thread);
                (void)spllo();

                (void)splsched();
                simple_lock(&thread_stack_lock);
        }

        assert_wait((event_t)&thread_stack_queue, THREAD_UNINT);
        simple_unlock(&thread_stack_lock);
        /* splsched */

        thread_block((thread_continue_t)thread_stack_daemon);
        /*NOTREACHED*/
}

/*
 *      thread_stack_enqueue:
 *
 *      Enqueue a thread for stack allocation.
 *
 *      Called at splsched.
 */
void
thread_stack_enqueue(
        thread_t                thread)
{
        simple_lock(&thread_stack_lock);
        enqueue_tail(&thread_stack_queue, (queue_entry_t)thread);
        simple_unlock(&thread_stack_lock);

        thread_wakeup((event_t)&thread_stack_queue);
}

void
thread_daemon_init(void)
{
        kern_return_t   result;
        thread_t                thread;

        simple_lock_init(&thread_terminate_lock, 0);
        queue_init(&thread_terminate_queue);

        result = kernel_thread_start_priority((thread_continue_t)thread_terminate_daemon, NULL, MINPRI_KERNEL, &thread);
        if (result != KERN_SUCCESS)
                panic("thread_daemon_init: thread_terminate_daemon");

        thread_deallocate(thread);

        simple_lock_init(&thread_stack_lock, 0);
        queue_init(&thread_stack_queue);

        result = kernel_thread_start_priority((thread_continue_t)thread_stack_daemon, NULL, BASEPRI_PREEMPT, &thread);
        if (result != KERN_SUCCESS)
                panic("thread_daemon_init: thread_stack_daemon");

        thread_deallocate(thread);
}

/*
 * Create a new thread.
 * Doesn't start the thread running.
 */
static kern_return_t
thread_create_internal(
        task_t                                  parent_task,
        integer_t                               priority,
        thread_continue_t               continuation,
        thread_t                                *out_thread)
{
        thread_t                                new_thread;
        processor_set_t                 pset;
        static thread_t                 first_thread;

        /*
         *      Allocate a thread and initialize static fields
         */
        if (first_thread == NULL)
                new_thread = first_thread = current_thread();
        else
                new_thread = (thread_t)zalloc(thread_zone);
        if (new_thread == NULL)
                return (KERN_RESOURCE_SHORTAGE);

        if (new_thread != first_thread)
                *new_thread = thread_template;

#ifdef MACH_BSD
    {
                new_thread->uthread = uthread_alloc(parent_task, new_thread);
                if (new_thread->uthread == NULL) {
                        zfree(thread_zone, new_thread);
                        return (KERN_RESOURCE_SHORTAGE);
                }
        }
#endif  /* MACH_BSD */

        if (machine_thread_create(new_thread, parent_task) != KERN_SUCCESS) {
#ifdef MACH_BSD
                {
                        void *ut = new_thread->uthread;

                        new_thread->uthread = NULL;
                        uthread_free(parent_task, ut, parent_task->bsd_info);
                }
#endif  /* MACH_BSD */
                zfree(thread_zone, new_thread);
                return (KERN_FAILURE);
        }

    new_thread->task = parent_task;

        thread_lock_init(new_thread);
        wake_lock_init(new_thread);

        mutex_init(&new_thread->mutex, 0);

        ipc_thread_init(new_thread);
        queue_init(&new_thread->held_ulocks);
        thread_prof_init(new_thread, parent_task);

        new_thread->continuation = continuation;

        pset = parent_task->processor_set;
        assert(pset == &default_pset);
        pset_lock(pset);

        task_lock(parent_task);
        assert(parent_task->processor_set == pset);

        if (    !parent_task->active                                                    ||
                        (parent_task->thread_count >= THREAD_MAX        &&
                         parent_task != kernel_task)) {
                task_unlock(parent_task);
                pset_unlock(pset);

#ifdef MACH_BSD
                {
                        void *ut = new_thread->uthread;

                        new_thread->uthread = NULL;
                        uthread_free(parent_task, ut, parent_task->bsd_info);
                }
#endif  /* MACH_BSD */
                ipc_thread_disable(new_thread);
                ipc_thread_terminate(new_thread);
                machine_thread_destroy(new_thread);
                zfree(thread_zone, new_thread);
                return (KERN_FAILURE);
        }

        task_reference_internal(parent_task);

        /* Cache the task's map */
        new_thread->map = parent_task->map;

        /* Chain the thread onto the task's list */
        queue_enter(&parent_task->threads, new_thread, thread_t, task_threads);
        parent_task->thread_count++;
        
        /* So terminating threads don't need to take the task lock to decrement */
        hw_atomic_add(&parent_task->active_thread_count, 1);

        /* Associate the thread with the processor set */
        pset_add_thread(pset, new_thread);

        timer_call_setup(&new_thread->wait_timer, thread_timer_expire, new_thread);
        timer_call_setup(&new_thread->depress_timer, thread_depress_expire, new_thread);

        /* Set the thread's scheduling parameters */
        if (parent_task != kernel_task)
                new_thread->sched_mode |= TH_MODE_TIMESHARE;
        new_thread->max_priority = parent_task->max_priority;
        new_thread->task_priority = parent_task->priority;
        new_thread->priority = (priority < 0)? parent_task->priority: priority;
        if (new_thread->priority > new_thread->max_priority)
                new_thread->priority = new_thread->max_priority;
        new_thread->importance =
                                        new_thread->priority - new_thread->task_priority;
        new_thread->sched_stamp = sched_tick;
        new_thread->pri_shift = new_thread->processor_set->pri_shift;
        compute_priority(new_thread, FALSE);

        new_thread->active = TRUE;

        *out_thread = new_thread;

        {
                long    dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4;

                kdbg_trace_data(parent_task->bsd_info, &dbg_arg2);

                KERNEL_DEBUG_CONSTANT(
                                        TRACEDBG_CODE(DBG_TRACE_DATA, 1) | DBG_FUNC_NONE,
                                                        (vm_address_t)new_thread, dbg_arg2, 0, 0, 0);

                kdbg_trace_string(parent_task->bsd_info,
                                                        &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4);

                KERNEL_DEBUG_CONSTANT(
                                        TRACEDBG_CODE(DBG_TRACE_STRING, 1) | DBG_FUNC_NONE,
                                                        dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, 0);
        }

        return (KERN_SUCCESS);
}

kern_return_t
thread_create(
        task_t                          task,
        thread_t                        *new_thread)
{
        kern_return_t           result;
        thread_t                        thread;

        if (task == TASK_NULL || task == kernel_task)
                return (KERN_INVALID_ARGUMENT);

        result = thread_create_internal(task, -1, (thread_continue_t)thread_bootstrap_return, &thread);
        if (result != KERN_SUCCESS)
                return (result);

        thread->user_stop_count = 1;
        thread_hold(thread);
        if (task->suspend_count > 0)
                thread_hold(thread);

        pset_unlock(task->processor_set);
        task_unlock(task);
        
        *new_thread = thread;

        return (KERN_SUCCESS);
}

kern_return_t
thread_create_running(
        register task_t         task,
        int                     flavor,
        thread_state_t          new_state,
        mach_msg_type_number_t  new_state_count,
        thread_t                                *new_thread)
{
        register kern_return_t  result;
        thread_t                                thread;

        if (task == TASK_NULL || task == kernel_task)
                return (KERN_INVALID_ARGUMENT);

        result = thread_create_internal(task, -1, (thread_continue_t)thread_bootstrap_return, &thread);
        if (result != KERN_SUCCESS)
                return (result);

        result = machine_thread_set_state(
                                                thread, flavor, new_state, new_state_count);
        if (result != KERN_SUCCESS) {
                pset_unlock(task->processor_set);
                task_unlock(task);

                thread_terminate(thread);
                thread_deallocate(thread);
                return (result);
        }

        thread_mtx_lock(thread);
        clear_wait(thread, THREAD_AWAKENED);
        thread->started = TRUE;
        thread_mtx_unlock(thread);
        pset_unlock(task->processor_set);
        task_unlock(task);

        *new_thread = thread;

        return (result);
}

/*
 *      kernel_thread_create:
 *
 *      Create a thread in the kernel task
 *      to execute in kernel context.
 */
kern_return_t
kernel_thread_create(
        thread_continue_t       continuation,
        void                            *parameter,
        integer_t                       priority,
        thread_t                        *new_thread)
{
        kern_return_t           result;
        thread_t                        thread;
        task_t                          task = kernel_task;

        result = thread_create_internal(task, priority, continuation, &thread);
        if (result != KERN_SUCCESS)
                return (result);

        pset_unlock(task->processor_set);
        task_unlock(task);

#if !defined(i386)
        stack_alloc(thread);
        assert(thread->kernel_stack != 0);
        thread->reserved_stack = thread->kernel_stack;
#endif /* !defined(i386) */

        thread->parameter = parameter;

        *new_thread = thread;

        return (result);
}

kern_return_t
kernel_thread_start_priority(
        thread_continue_t       continuation,
        void                            *parameter,
        integer_t                       priority,
        thread_t                        *new_thread)
{
        kern_return_t   result;
        thread_t                thread;

        result = kernel_thread_create(continuation, parameter, priority, &thread);
        if (result != KERN_SUCCESS)
                return (result);

        thread_mtx_lock(thread);
        clear_wait(thread, THREAD_AWAKENED);
        thread->started = TRUE;
        thread_mtx_unlock(thread);

        *new_thread = thread;

        return (result);
}

kern_return_t
kernel_thread_start(
        thread_continue_t       continuation,
        void                            *parameter,
        thread_t                        *new_thread)
{
        return kernel_thread_start_priority(continuation, parameter, -1, new_thread);
}

thread_t
kernel_thread(
        task_t                  task,
        void                    (*start)(void))
{
        kern_return_t   result;
        thread_t                thread;

        if (task != kernel_task)
                panic("kernel_thread");

        result = kernel_thread_start_priority((thread_continue_t)start, NULL, -1, &thread);
        if (result != KERN_SUCCESS)
                return (THREAD_NULL);

        thread_deallocate(thread);

        return (thread);
}

kern_return_t
thread_info_internal(
        register thread_t               thread,
        thread_flavor_t                 flavor,
        thread_info_t                   thread_info_out,        /* ptr to OUT array */
        mach_msg_type_number_t  *thread_info_count)     /*IN/OUT*/
{
        int                                             state, flags;
        spl_t                                   s;

        if (thread == THREAD_NULL)
                return (KERN_INVALID_ARGUMENT);

        if (flavor == THREAD_BASIC_INFO) {
            register thread_basic_info_t        basic_info;

            if (*thread_info_count < THREAD_BASIC_INFO_COUNT)
                        return (KERN_INVALID_ARGUMENT);

            basic_info = (thread_basic_info_t) thread_info_out;

            s = splsched();
            thread_lock(thread);

            /* fill in info */

            thread_read_times(thread, &basic_info->user_time,
                                                                        &basic_info->system_time);

                /*
                 *      Update lazy-evaluated scheduler info because someone wants it.
                 */
                if (thread->sched_stamp != sched_tick)
                        update_priority(thread);

                basic_info->sleep_time = 0;

                /*
                 *      To calculate cpu_usage, first correct for timer rate,
                 *      then for 5/8 ageing.  The correction factor [3/5] is
                 *      (1/(5/8) - 1).
                 */
                basic_info->cpu_usage = ((uint64_t)thread->cpu_usage
                                                                        * TH_USAGE_SCALE) /     sched_tick_interval;
                basic_info->cpu_usage = (basic_info->cpu_usage * 3) / 5;

                if (basic_info->cpu_usage > TH_USAGE_SCALE)
                        basic_info->cpu_usage = TH_USAGE_SCALE;

                basic_info->policy = ((thread->sched_mode & TH_MODE_TIMESHARE)?
                                                                                                POLICY_TIMESHARE: POLICY_RR);

            flags = 0;
                if (thread->state & TH_IDLE)
                        flags |= TH_FLAGS_IDLE;

            if (!thread->kernel_stack)
                        flags |= TH_FLAGS_SWAPPED;

            state = 0;
            if (thread->state & TH_TERMINATE)
                        state = TH_STATE_HALTED;
            else
                if (thread->state & TH_RUN)
                        state = TH_STATE_RUNNING;
            else
                if (thread->state & TH_UNINT)
                        state = TH_STATE_UNINTERRUPTIBLE;
            else
                if (thread->state & TH_SUSP)
                        state = TH_STATE_STOPPED;
            else
                if (thread->state & TH_WAIT)
                        state = TH_STATE_WAITING;

            basic_info->run_state = state;
            basic_info->flags = flags;

            basic_info->suspend_count = thread->user_stop_count;

            thread_unlock(thread);
            splx(s);

            *thread_info_count = THREAD_BASIC_INFO_COUNT;

            return (KERN_SUCCESS);
        }
        else
        if (flavor == THREAD_SCHED_TIMESHARE_INFO) {
                policy_timeshare_info_t         ts_info;

                if (*thread_info_count < POLICY_TIMESHARE_INFO_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                ts_info = (policy_timeshare_info_t)thread_info_out;

            s = splsched();
                thread_lock(thread);

            if (!(thread->sched_mode & TH_MODE_TIMESHARE)) {
                thread_unlock(thread);
                        splx(s);

                        return (KERN_INVALID_POLICY);
            }

                ts_info->depressed = (thread->sched_mode & TH_MODE_ISDEPRESSED) != 0;
                if (ts_info->depressed) {
                        ts_info->base_priority = DEPRESSPRI;
                        ts_info->depress_priority = thread->priority;
                }
                else {
                        ts_info->base_priority = thread->priority;
                        ts_info->depress_priority = -1;
                }

                ts_info->cur_priority = thread->sched_pri;
                ts_info->max_priority = thread->max_priority;

                thread_unlock(thread);
            splx(s);

                *thread_info_count = POLICY_TIMESHARE_INFO_COUNT;

                return (KERN_SUCCESS);  
        }
        else
        if (flavor == THREAD_SCHED_FIFO_INFO) {
                if (*thread_info_count < POLICY_FIFO_INFO_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                return (KERN_INVALID_POLICY);
        }
        else
        if (flavor == THREAD_SCHED_RR_INFO) {
                policy_rr_info_t                        rr_info;

                if (*thread_info_count < POLICY_RR_INFO_COUNT)
                        return (KERN_INVALID_ARGUMENT);

                rr_info = (policy_rr_info_t) thread_info_out;

            s = splsched();
                thread_lock(thread);

            if (thread->sched_mode & TH_MODE_TIMESHARE) {
                thread_unlock(thread);
                        splx(s);

                        return (KERN_INVALID_POLICY);
            }

                rr_info->depressed = (thread->sched_mode & TH_MODE_ISDEPRESSED) != 0;
                if (rr_info->depressed) {
                        rr_info->base_priority = DEPRESSPRI;
                        rr_info->depress_priority = thread->priority;
                }
                else {
                        rr_info->base_priority = thread->priority;
                        rr_info->depress_priority = -1;
                }

                rr_info->max_priority = thread->max_priority;
            rr_info->quantum = std_quantum_us / 1000;

                thread_unlock(thread);
            splx(s);

                *thread_info_count = POLICY_RR_INFO_COUNT;

                return (KERN_SUCCESS);  
        }

        return (KERN_INVALID_ARGUMENT);
}

void
thread_read_times(
        thread_t                thread,
        time_value_t    *user_time,
        time_value_t    *system_time)
{
        absolutetime_to_microtime(
                        timer_grab(&thread->user_timer),
                                                        &user_time->seconds, &user_time->microseconds);

        absolutetime_to_microtime(
                        timer_grab(&thread->system_timer),
                                                        &system_time->seconds, &system_time->microseconds);
}

kern_return_t
thread_assign(
        __unused thread_t                       thread,
        __unused processor_set_t        new_pset)
{
        return (KERN_FAILURE);
}

/*
 *      thread_assign_default:
 *
 *      Special version of thread_assign for assigning threads to default
 *      processor set.
 */
kern_return_t
thread_assign_default(
        thread_t                thread)
{
        return (thread_assign(thread, &default_pset));
}

/*
 *      thread_get_assignment
 *
 *      Return current assignment for this thread.
 */         
kern_return_t
thread_get_assignment(
        thread_t                thread,
        processor_set_t *pset)
{
        if (thread == NULL)
                return (KERN_INVALID_ARGUMENT);

        *pset = thread->processor_set;
        pset_reference(*pset);
        return (KERN_SUCCESS);
}

/*
 *      thread_wire_internal:
 *
 *      Specify that the target thread must always be able
 *      to run and to allocate memory.
 */
kern_return_t
thread_wire_internal(
        host_priv_t             host_priv,
        thread_t                thread,
        boolean_t               wired,
        boolean_t               *prev_state)
{
        if (host_priv == NULL || thread != current_thread())
                return (KERN_INVALID_ARGUMENT);

        assert(host_priv == &realhost);

        if (prev_state)
            *prev_state = (thread->options & TH_OPT_VMPRIV) != 0;
        
        if (wired) {
            if (!(thread->options & TH_OPT_VMPRIV)) 
                    vm_page_free_reserve(1);    /* XXX */
            thread->options |= TH_OPT_VMPRIV;
        }
        else {
            if (thread->options & TH_OPT_VMPRIV) 
                    vm_page_free_reserve(-1);   /* XXX */
            thread->options &= ~TH_OPT_VMPRIV;
        }

        return (KERN_SUCCESS);
}


/*
 *      thread_wire:
 *
 *      User-api wrapper for thread_wire_internal()
 */
kern_return_t
thread_wire(
        host_priv_t     host_priv,
        thread_t        thread,
        boolean_t       wired)
{
    return (thread_wire_internal(host_priv, thread, wired, NULL));
}

int             split_funnel_off = 0;
lck_grp_t       *funnel_lck_grp = LCK_GRP_NULL;
lck_grp_attr_t  *funnel_lck_grp_attr;
lck_attr_t      *funnel_lck_attr;

funnel_t *
funnel_alloc(
        int type)
{
        lck_mtx_t       *m;
        funnel_t        *fnl;

        if (funnel_lck_grp == LCK_GRP_NULL) {
                funnel_lck_grp_attr = lck_grp_attr_alloc_init();
                //lck_grp_attr_setstat(funnel_lck_grp_attr);

                funnel_lck_grp = lck_grp_alloc_init("Funnel",  funnel_lck_grp_attr);

                funnel_lck_attr = lck_attr_alloc_init();
                //lck_attr_setdebug(funnel_lck_attr);
        }
        if ((fnl = (funnel_t *)kalloc(sizeof(funnel_t))) != 0){
                bzero((void *)fnl, sizeof(funnel_t));
                if ((m = lck_mtx_alloc_init(funnel_lck_grp, funnel_lck_attr)) == (lck_mtx_t *)NULL) {
                        kfree(fnl, sizeof(funnel_t));
                        return(THR_FUNNEL_NULL);
                }
                fnl->fnl_mutex = m;
                fnl->fnl_type = type;
        }
        return(fnl);
}

void 
funnel_free(
        funnel_t * fnl)
{
        lck_mtx_free(fnl->fnl_mutex, funnel_lck_grp);
        if (fnl->fnl_oldmutex)
                lck_mtx_free(fnl->fnl_oldmutex, funnel_lck_grp);
        kfree(fnl, sizeof(funnel_t));
}

void 
funnel_lock(
        funnel_t * fnl)
{
        lck_mtx_lock(fnl->fnl_mutex);
        fnl->fnl_mtxholder = current_thread();
}

void 
funnel_unlock(
        funnel_t * fnl)
{
        lck_mtx_unlock(fnl->fnl_mutex);
        fnl->fnl_mtxrelease = current_thread();
}

funnel_t *
thread_funnel_get(
        void)
{
        thread_t th = current_thread();

        if (th->funnel_state & TH_FN_OWNED) {
                return(th->funnel_lock);
        }
        return(THR_FUNNEL_NULL);
}

boolean_t
thread_funnel_set(
        funnel_t *      fnl,
        boolean_t       funneled)
{
        thread_t        cur_thread;
        boolean_t       funnel_state_prev;
        boolean_t       intr;
        
        cur_thread = current_thread();
        funnel_state_prev = ((cur_thread->funnel_state & TH_FN_OWNED) == TH_FN_OWNED);

        if (funnel_state_prev != funneled) {
                intr = ml_set_interrupts_enabled(FALSE);

                if (funneled == TRUE) {
                        if (cur_thread->funnel_lock)
                                panic("Funnel lock called when holding one %x", cur_thread->funnel_lock);
                        KERNEL_DEBUG(0x6032428 | DBG_FUNC_NONE,
                                                                                        fnl, 1, 0, 0, 0);
                        funnel_lock(fnl);
                        KERNEL_DEBUG(0x6032434 | DBG_FUNC_NONE,
                                                                                        fnl, 1, 0, 0, 0);
                        cur_thread->funnel_state |= TH_FN_OWNED;
                        cur_thread->funnel_lock = fnl;
                } else {
                        if(cur_thread->funnel_lock->fnl_mutex != fnl->fnl_mutex)
                                panic("Funnel unlock  when not holding funnel");
                        cur_thread->funnel_state &= ~TH_FN_OWNED;
                        KERNEL_DEBUG(0x603242c | DBG_FUNC_NONE,
                                                                fnl, 1, 0, 0, 0);

                        cur_thread->funnel_lock = THR_FUNNEL_NULL;
                        funnel_unlock(fnl);
                }
                (void)ml_set_interrupts_enabled(intr);
        } else {
                /* if we are trying to acquire funnel recursively
                 * check for funnel to be held already
                 */
                if (funneled && (fnl->fnl_mutex != cur_thread->funnel_lock->fnl_mutex)) {
                                panic("thread_funnel_set: already holding a different funnel");
                }
        }
        return(funnel_state_prev);
}


/*
 * Export routines to other components for things that are done as macros
 * within the osfmk component.
 */

#undef thread_reference
void thread_reference(thread_t thread);
void
thread_reference(
        thread_t        thread)
{
        if (thread != THREAD_NULL)
                thread_reference_internal(thread);
}

#undef thread_should_halt

boolean_t
thread_should_halt(
        thread_t                th)
{
        return (thread_should_halt_fast(th));
}