]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/kern/thread_act.c
xnu-792.13.8.tar.gz
[apple/xnu.git] / osfmk / kern / thread_act.c
index 9a97f50a6eaba53bc028c7309cb4664e5e6a2d9b..71edcc7887161d72397531658069ce733fb846ca 100644 (file)
@@ -1,23 +1,31 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_LICENSE_OSREFERENCE_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@
+ * This file contains Original Code and/or Modifications of Original Code 
+ * as defined in and that are subject to the Apple Public Source License 
+ * Version 2.0 (the 'License'). You may not use this file except in 
+ * compliance with the License.  The rights granted to you under the 
+ * License may not be used to create, or enable the creation or 
+ * redistribution of, unlawful or unlicensed copies of an Apple operating 
+ * system, or to circumvent, violate, or enable the circumvention or 
+ * violation of, any terms of an Apple operating system software license 
+ * agreement.
+ *
+ * Please obtain a copy of the License at 
+ * http://www.opensource.apple.com/apsl/ and read it before using this 
+ * file.
+ *
+ * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
+ * Please see the License for the specific language governing rights and 
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  */
 /*
  * @OSF_FREE_COPYRIGHT@
  *
  *     Author: Bryan Ford, University of Utah CSS
  *
- *     Thread_Activation management routines
+ *     Thread management routines
  */
-
-#include <cpus.h>
-#include <task_swapper.h>
+#include <mach/mach_types.h>
 #include <mach/kern_return.h>
 #include <mach/alert.h>
-#include <kern/etap_macros.h>
+#include <mach_prof.h>
+#include <mach/rpc.h>
+#include <mach/thread_act_server.h>
+
+#include <kern/kern_types.h>
+#include <kern/ast.h>
 #include <kern/mach_param.h>
 #include <kern/zalloc.h>
 #include <kern/thread.h>
-#include <kern/thread_swap.h>
 #include <kern/task.h>
-#include <kern/task_swap.h>
-#include <kern/thread_act.h>
-#include <kern/thread_pool.h>
 #include <kern/sched_prim.h>
 #include <kern/misc_protos.h>
 #include <kern/assert.h>
 #include <kern/spl.h>
 #include <kern/syscall_subr.h>
 #include <kern/sync_lock.h>
-#include <kern/sf.h>
-#include <kern/mk_sp.h>        /*** ??? fix so this can be removed ***/
+#include <kern/processor.h>
+#include <kern/timer.h>
 #include <mach_prof.h>
 #include <mach/rpc.h>
 
-/*
- * Debugging printf control
- */
-#if    MACH_ASSERT
-unsigned int   watchacts =       0 /* WA_ALL */
-                                   ;   /* Do-it-yourself & patchable */
-#endif
-
-/*
- * Track the number of times we need to swapin a thread to deallocate it.
- */
-int act_free_swapin = 0;
-
-/*
- * Forward declarations for functions local to this file.
- */
-kern_return_t  act_abort( thread_act_t, int);
-void           special_handler(ReturnHandler *, thread_act_t);
-void           nudge(thread_act_t);
-kern_return_t  act_set_state_locked(thread_act_t, int,
-                                       thread_state_t,
-                                       mach_msg_type_number_t);
-kern_return_t  act_get_state_locked(thread_act_t, int,
-                                       thread_state_t,
-                                       mach_msg_type_number_t *);
-void           act_set_apc(thread_act_t);
-void           act_clr_apc(thread_act_t);
-void           act_user_to_kernel(thread_act_t);
-void           act_ulock_release_all(thread_act_t thr_act);
-
-void           install_special_handler_locked(thread_act_t);
-
-static zone_t  thr_act_zone;
-
-/*
- * Thread interfaces accessed via a thread_activation:
- */
-
+void                   act_abort(thread_t);
+void                   act_set_apc(thread_t);
+void                   install_special_handler_locked(thread_t);
+void                   special_handler_continue(void);
 
 /*
  * Internal routine to terminate a thread.
- * Called with task locked.
+ * Sometimes called with task already locked.
  */
 kern_return_t
 thread_terminate_internal(
-       register thread_act_t   thr_act)
+       thread_t                        thread)
 {
-       thread_t        thread;
-       task_t          task;
-       struct ipc_port *iplock;
-       kern_return_t   ret;
-
-#if    THREAD_SWAPPER
-       thread_swap_disable(thr_act);
-#endif /* THREAD_SWAPPER */
-
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return(KERN_TERMINATED);
-       }
+       kern_return_t           result = KERN_SUCCESS;
 
-       act_disable_task_locked(thr_act);
-       ret = act_abort(thr_act,FALSE);
+       thread_mtx_lock(thread);
 
-#if    NCPUS > 1
-       /* 
-        * Make sure this thread enters the kernel
-        */
-       if (thread != current_thread()) {
-               thread_hold(thr_act);
-               act_unlock_thread(thr_act);
+       if (thread->active) {
+               thread->active = FALSE;
 
-               if (thread_stop_wait(thread))
-                       thread_unstop(thread);
-               else
-                       ret = KERN_ABORTED;
+               act_abort(thread);
 
-               (void)act_lock_thread(thr_act);
-               thread_release(thr_act);
+               if (thread->started)
+                       clear_wait(thread, THREAD_INTERRUPTED);
+               else {
+                       clear_wait(thread, THREAD_AWAKENED);
+                       thread->started = TRUE;
+               }
        }
-#endif /* NCPUS > 1 */
+       else
+               result = KERN_TERMINATED;
 
-       act_unlock_thread(thr_act);
-       return(ret);
+       thread_mtx_unlock(thread);
+
+       if (thread != current_thread() && result == KERN_SUCCESS)
+               thread_wait(thread);
+
+       return (result);
 }
 
 /*
- * Terminate a thread.  Called with nothing locked.
- * Returns same way.
+ * Terminate a thread.
  */
 kern_return_t
 thread_terminate(
-       register thread_act_t   thr_act)
+       thread_t                thread)
 {
-       task_t          task;
-       kern_return_t   ret;
+       kern_return_t   result;
 
-       if (thr_act == THR_ACT_NULL)
-               return KERN_INVALID_ARGUMENT;
+       if (thread == THREAD_NULL)
+               return (KERN_INVALID_ARGUMENT);
 
-       task = thr_act->task;
-       if (((task == kernel_task) || (thr_act->kernel_loaded == TRUE))
-           && (current_act() != thr_act)) {
-               return(KERN_FAILURE);
-        }
+       if (    thread->task == kernel_task             &&
+                       thread != current_thread()                      )
+               return (KERN_FAILURE);
 
-       /*
-        * Take the task lock and then call the internal routine
-        * that terminates a thread (it needs the task locked).
-        */
-       task_lock(task);
-       ret = thread_terminate_internal(thr_act);
-       task_unlock(task);
+       result = thread_terminate_internal(thread);
 
        /*
         * If a kernel thread is terminating itself, force an AST here.
@@ -194,146 +144,117 @@ thread_terminate(
         * code - and all threads finish their own termination in the
         * special handler APC.
         */
-       if (((thr_act->task == kernel_task) || (thr_act->kernel_loaded == TRUE))
-           && (current_act() == thr_act)) {
-               ast_taken(FALSE, AST_APC, 0);
-               panic("thread_terminate(): returning from ast_taken() for %x kernel activation\n", thr_act);
-        }
+       if (thread->task == kernel_task) {
+               ml_set_interrupts_enabled(FALSE);
+               ast_taken(AST_APC, TRUE);
+               panic("thread_terminate");
+       }
 
-       return ret;
+       return (result);
 }
 
 /*
- *     thread_hold:
+ * Suspend execution of the specified thread.
+ * This is a recursive-style suspension of the thread, a count of
+ * suspends is maintained.
  *
- *     Suspend execution of the specified thread.
- *     This is a recursive-style suspension of the thread, a count of
- *     suspends is maintained.
- *
- *     Called with thr_act locked "appropriately" for synchrony with
- *     RPC (see act_lock_thread()).  Returns same way.
+ * Called with thread mutex held.
  */
 void
 thread_hold(
-       register thread_act_t   thr_act)
+       register thread_t       thread)
 {
-       if (thr_act->suspend_count++ == 0) {
-               install_special_handler(thr_act);
-               nudge(thr_act);
+       if (thread->suspend_count++ == 0) {
+               install_special_handler(thread);
+               if (thread->started)
+                       thread_wakeup_one(&thread->suspend_count);
        }
 }
 
 /*
- * Decrement internal suspension count for thr_act, setting thread
+ * Decrement internal suspension count, setting thread
  * runnable when count falls to zero.
  *
- * Called with thr_act locked "appropriately" for synchrony
- * with RPC (see act_lock_thread()).
+ * Called with thread mutex held.
  */
 void
 thread_release(
-       register thread_act_t   thr_act)
+       register thread_t       thread)
 {
-       if( thr_act->suspend_count &&
-               (--thr_act->suspend_count == 0) )
-               nudge( thr_act );
+       if (    thread->suspend_count > 0               &&
+                       --thread->suspend_count == 0    ) {
+               if (thread->started)
+                       thread_wakeup_one(&thread->suspend_count);
+               else {
+                       clear_wait(thread, THREAD_AWAKENED);
+                       thread->started = TRUE;
+               }
+       }
 }
 
 kern_return_t
 thread_suspend(
-       register thread_act_t   thr_act)
+       register thread_t       thread)
 {
-       thread_t                thread;
+       thread_t                        self = current_thread();
+       kern_return_t           result = KERN_SUCCESS;
 
-       if (thr_act == THR_ACT_NULL) {
-               return(KERN_INVALID_ARGUMENT);
-       }
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return(KERN_TERMINATED);
-       }
-       if (thr_act->user_stop_count++ == 0 &&
-               thr_act->suspend_count++ == 0 ) {
-               install_special_handler(thr_act);
-               if (thread &&
-                       thr_act == thread->top_act && thread != current_thread()) {
-                       nudge(thr_act);
-                       act_unlock_thread(thr_act);
-                       (void)thread_wait(thread);
-               }
-               else {
-                       /*
-                        * No need to wait for target thread
-                        */
-                       act_unlock_thread(thr_act);
+       if (thread == THREAD_NULL || thread->task == kernel_task)
+               return (KERN_INVALID_ARGUMENT);
+
+       thread_mtx_lock(thread);
+
+       if (thread->active) {
+               if (    thread->user_stop_count++ == 0          &&
+                               thread->suspend_count++ == 0            ) {
+                       install_special_handler(thread);
+                       if (thread != self)
+                               thread_wakeup_one(&thread->suspend_count);
                }
        }
-       else {
-               /*
-                * Thread is already suspended
-                */
-               act_unlock_thread(thr_act);
-       }
-       return(KERN_SUCCESS);
+       else
+               result = KERN_TERMINATED;
+
+       thread_mtx_unlock(thread);
+
+       if (thread != self && result == KERN_SUCCESS)
+               thread_wait(thread);
+
+       return (result);
 }
 
 kern_return_t
 thread_resume(
-       register thread_act_t   thr_act)
+       register thread_t       thread)
 {
-       register kern_return_t  ret;
-       spl_t                   s;
-       thread_t                thread;
-
-       if (thr_act == THR_ACT_NULL)
-               return(KERN_INVALID_ARGUMENT);
-       thread = act_lock_thread(thr_act);
-       ret = KERN_SUCCESS;
-
-       if (thr_act->active) {
-               if (thr_act->user_stop_count > 0) {
-                       if( --thr_act->user_stop_count == 0 ) {
-                               --thr_act->suspend_count;
-                               nudge( thr_act );
+       kern_return_t           result = KERN_SUCCESS;
+
+       if (thread == THREAD_NULL || thread->task == kernel_task)
+               return (KERN_INVALID_ARGUMENT);
+
+       thread_mtx_lock(thread);
+
+       if (thread->active) {
+               if (thread->user_stop_count > 0) {
+                       if (    --thread->user_stop_count == 0          &&
+                                       --thread->suspend_count == 0            ) {
+                               if (thread->started)
+                                       thread_wakeup_one(&thread->suspend_count);
+                               else {
+                                       clear_wait(thread, THREAD_AWAKENED);
+                                       thread->started = TRUE;
+                               }
                        }
                }
                else
-                       ret = KERN_FAILURE;
+                       result = KERN_FAILURE;
        }
        else
-               ret = KERN_TERMINATED;
-       act_unlock_thread( thr_act );
-       return ret;
-}
-
-/* 
- * This routine walks toward the head of an RPC chain starting at
- * a specified thread activation. An alert bit is set and a special 
- * handler is installed for each thread it encounters.
- *
- * The target thread act and thread shuttle are already locked.
- */
-kern_return_t
-post_alert( 
-       register thread_act_t   thr_act,
-       unsigned                alert_bits )
-{
-       thread_act_t    next;
-       thread_t        thread;
+               result = KERN_TERMINATED;
 
-       /* 
-        * Chase the chain, setting alert bits and installing
-        * special handlers for each thread act.
-        */
-       /*** Not yet SMP safe ***/
-       /*** Worse, where's the activation locking as the chain is walked? ***/
-       for (next = thr_act; next != THR_ACT_NULL; next = next->higher) {
-               next->alerts |= alert_bits;
-               install_special_handler_locked(next);
-       }
+       thread_mtx_unlock(thread);
 
-       return(KERN_SUCCESS);
+       return (result);
 }
 
 /*
@@ -343,525 +264,315 @@ post_alert(
  */
 kern_return_t
 thread_depress_abort(
-       register thread_act_t   thr_act)
+       register thread_t       thread)
 {
-    register thread_t          thread;
-       kern_return_t                   result;
-    sched_policy_t                     *policy;
-    spl_t                                      s;
+       kern_return_t           result;
 
-    if (thr_act == THR_ACT_NULL)
+    if (thread == THREAD_NULL)
                return (KERN_INVALID_ARGUMENT);
 
-    thread = act_lock_thread(thr_act);
-    /* if activation is terminating, this operation is not meaningful */
-    if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-
-               return (KERN_TERMINATED);
-    }
+    thread_mtx_lock(thread);
 
-    s = splsched();
-    thread_lock(thread);
-    policy = &sched_policy[thread->policy];
-    thread_unlock(thread);
-    splx(s);
-
-    result = policy->sp_ops.sp_thread_depress_abort(policy, thread);
+       if (thread->active)
+               result = thread_depress_abort_internal(thread);
+       else
+               result = KERN_TERMINATED;
 
-    act_unlock_thread(thr_act);
+    thread_mtx_unlock(thread);
 
        return (result);
 }
 
 
 /*
- * Already locked: all RPC-related locks for thr_act (see
- * act_lock_thread()).
+ * Indicate that the activation should run its
+ * special handler to detect a condition.
+ *
+ * Called with thread mutex held.
  */
-kern_return_t
-act_abort( thread_act_t thr_act, int chain_break )
+void
+act_abort(
+       thread_t        thread)
 {
-       spl_t                   spl;
-       thread_t                thread;
-       struct ipc_port         *iplock = thr_act->pool_port;
-       thread_act_t            orphan;
-       kern_return_t           kr;
-       etap_data_t             probe_data;
-
-       ETAP_DATA_LOAD(probe_data[0], thr_act);
-       ETAP_DATA_LOAD(probe_data[1], thr_act->thread);
-       ETAP_PROBE_DATA(ETAP_P_ACT_ABORT,
-                       0,
-                       current_thread(),
-                       &probe_data,
-                       ETAP_DATA_ENTRY*2);
-
-       /*
-        *  If the target thread activation is not the head... 
-        */
-       if ( thr_act->thread->top_act != thr_act ) {
-               /*
-                * mark the activation for abort,
-                * update the suspend count,
-                * always install the special handler
-                */
-               install_special_handler(thr_act);
-
-#ifdef AGRESSIVE_ABORT
-               /* release state buffer for target's outstanding invocation */
-               if (unwind_invoke_state(thr_act) != KERN_SUCCESS) {
-                       panic("unwind_invoke_state failure");
-               }
-
-               /* release state buffer for target's incoming invocation */
-               if (thr_act->lower != THR_ACT_NULL) {
-                       if (unwind_invoke_state(thr_act->lower)
-                           != KERN_SUCCESS) {
-                               panic("unwind_invoke_state failure");
-                       }
-               }
-
-               /* unlink target thread activation from shuttle chain */
-               if ( thr_act->lower == THR_ACT_NULL ) {
-                       /*
-                        * This is the root thread activation of the chain.
-                        * Unlink the root thread act from the bottom of
-                        * the chain.
-                        */
-                       thr_act->higher->lower = THR_ACT_NULL;
-               } else {
-                       /*
-                        * This thread act is in the middle of the chain.
-                        * Unlink the thread act from the middle of the chain.
-                        */
-                       thr_act->higher->lower = thr_act->lower;
-                       thr_act->lower->higher = thr_act->higher;
-
-                       /* set the terminated bit for RPC return processing */
-                       thr_act->lower->alerts |= SERVER_TERMINATED;
-               }
-
-               orphan = thr_act->higher;
+       spl_t           s = splsched();
 
-               /* remove the activation from its thread pool */
-               /* (note: this is okay for "rooted threads," too) */
-               act_locked_act_set_thread_pool(thr_act, IP_NULL);
-
-               /* (just to be thorough) release the IP lock */
-               if (iplock != IP_NULL) ip_unlock(iplock);
-
-               /* release one more reference for a rooted thread */
-               if (iplock == IP_NULL) act_locked_act_deallocate(thr_act);
+       thread_lock(thread);
 
-               /* Presumably, the only reference to this activation is
-                * now held by the caller of this routine. */
-               assert(thr_act->ref_count == 1);
-#else /*AGRESSIVE_ABORT*/
-               /* If there is a lower activation in the RPC chain... */
-               if (thr_act->lower != THR_ACT_NULL) {
-                       /* ...indicate the server activation was terminated */
-                       thr_act->lower->alerts |= SERVER_TERMINATED;
-               }
-               /* Mark (and process) any orphaned activations */
-               orphan = thr_act->higher;
-#endif /*AGRESSIVE_ABORT*/
-
-               /* indicate client of orphaned chain has been terminated */
-               orphan->alerts |= CLIENT_TERMINATED;
-
-               /* 
-                * Set up posting of alert to headward portion of
-                * the RPC chain.
-                */
-               /*** fix me -- orphan act is not locked ***/
-               post_alert(orphan, ORPHANED);
-
-               /*
-                * Get attention of head of RPC chain.
-                */
-               nudge(thr_act->thread->top_act);
-               return (KERN_SUCCESS);
+       if (!(thread->state & TH_ABORT)) {
+               thread->state |= TH_ABORT;
+               install_special_handler_locked(thread);
        }
+       else
+               thread->state &= ~TH_ABORT_SAFELY;
 
-       /*
-        * If the target thread is the end of the chain, the thread
-        * has to be marked for abort and rip it out of any wait.
-        */
-       spl = splsched();
-       thread_lock(thr_act->thread);
-       if (thr_act->thread->top_act == thr_act) {
-           thr_act->thread->state |= TH_ABORT;
-           clear_wait_internal(thr_act->thread, THREAD_INTERRUPTED);
-           thread_unlock(thr_act->thread);
-           splx(spl);
-           install_special_handler(thr_act);
-           nudge( thr_act );
-       }
-       return KERN_SUCCESS;
+       thread_unlock(thread);
+       splx(s);
 }
        
 kern_return_t
 thread_abort(
-       register thread_act_t   thr_act)
+       register thread_t       thread)
 {
-       int             ret;
-       thread_t                thread;
+       kern_return_t   result = KERN_SUCCESS;
 
-       if (thr_act == THR_ACT_NULL || thr_act == current_act())
+       if (thread == THREAD_NULL)
                return (KERN_INVALID_ARGUMENT);
-       /*
-        *      Lock the target thread and the current thread now,
-        *      in case thread_halt() ends up being called below.
-        */
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return(KERN_TERMINATED);
+
+       thread_mtx_lock(thread);
+
+       if (thread->active) {
+               act_abort(thread);
+               clear_wait(thread, THREAD_INTERRUPTED);
        }
+       else
+               result = KERN_TERMINATED;
+
+       thread_mtx_unlock(thread);
 
-       ret = act_abort( thr_act, FALSE );
-       act_unlock_thread( thr_act );
-       return ret;
+       return (result);
 }
 
 kern_return_t
 thread_abort_safely(
-       register thread_act_t   thr_act)
+       thread_t                thread)
 {
-       thread_t                thread;
-       spl_t                   s;
+       kern_return_t   result = KERN_SUCCESS;
 
-       if (thr_act == THR_ACT_NULL || thr_act == current_act())
-               return(KERN_INVALID_ARGUMENT);
+       if (thread == THREAD_NULL)
+               return (KERN_INVALID_ARGUMENT);
 
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return(KERN_TERMINATED);
-       }
-       if (thread->top_act != thr_act) {
-               act_unlock_thread(thr_act);
-               return(KERN_FAILURE);
-       }
-       s = splsched();
-       thread_lock(thread);
+       thread_mtx_lock(thread);
 
-       if ( thread->at_safe_point ) {
-               /*
-                * It's an abortable wait, clear it, then
-                * let the thread go and return successfully.
-                */
-               clear_wait_internal(thread, THREAD_INTERRUPTED);
+       if (thread->active) {
+               spl_t           s = splsched();
+
+               thread_lock(thread);
+               if (!thread->at_safe_point ||
+                       clear_wait_internal(thread, THREAD_INTERRUPTED) != KERN_SUCCESS) {
+                       if (!(thread->state & TH_ABORT)) {
+                               thread->state |= (TH_ABORT|TH_ABORT_SAFELY);
+                               install_special_handler_locked(thread);
+                       }
+               }
                thread_unlock(thread);
-               act_unlock_thread(thr_act);
                splx(s);
-               return KERN_SUCCESS;
        }
+       else
+               result = KERN_TERMINATED;
+               
+       thread_mtx_unlock(thread);
 
-       /*
-        * if not stopped at a safepoint, just let it go and return failure.
-        */
-       thread_unlock(thread);
-       act_unlock_thread(thr_act);
-       splx(s);
-       return KERN_FAILURE;
+       return (result);
 }
 
 /*** backward compatibility hacks ***/
 #include <mach/thread_info.h>
 #include <mach/thread_special_ports.h>
 #include <ipc/ipc_port.h>
-#include <mach/thread_act_server.h>
 
 kern_return_t
 thread_info(
-       thread_act_t                    thr_act,
+       thread_t                                thread,
        thread_flavor_t                 flavor,
        thread_info_t                   thread_info_out,
        mach_msg_type_number_t  *thread_info_count)
 {
-       register thread_t               thread;
        kern_return_t                   result;
 
-       if (thr_act == THR_ACT_NULL)
+       if (thread == THREAD_NULL)
                return (KERN_INVALID_ARGUMENT);
 
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-
-               return (KERN_TERMINATED);
-       }
+       thread_mtx_lock(thread);
 
-       result = thread_info_shuttle(thr_act, flavor,
-                                       thread_info_out, thread_info_count);
+       if (thread->active)
+               result = thread_info_internal(
+                                               thread, flavor, thread_info_out, thread_info_count);
+       else
+               result = KERN_TERMINATED;
 
-       act_unlock_thread(thr_act);
+       thread_mtx_unlock(thread);
 
        return (result);
 }
 
-/*
- *     Routine:        thread_get_special_port [kernel call]
- *     Purpose:
- *             Clones a send right for one of the thread's
- *             special ports.
- *     Conditions:
- *             Nothing locked.
- *     Returns:
- *             KERN_SUCCESS            Extracted a send right.
- *             KERN_INVALID_ARGUMENT   The thread is null.
- *             KERN_FAILURE            The thread is dead.
- *             KERN_INVALID_ARGUMENT   Invalid special port.
- */
-
 kern_return_t
-thread_get_special_port(
-       thread_act_t    thr_act,
-       int             which,
-       ipc_port_t      *portp)
+thread_get_state(
+       register thread_t               thread,
+       int                                             flavor,
+       thread_state_t                  state,                  /* pointer to OUT array */
+       mach_msg_type_number_t  *state_count)   /*IN/OUT*/
 {
-       ipc_port_t      *whichp;
-       ipc_port_t      port;
-       thread_t        thread;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_PORT)
-           printf("thread_get_special_port(thr_act=%x, which=%x port@%x=%x\n",
-               thr_act, which, portp, (portp ? *portp : 0));
-#endif /* MACH_ASSERT */
-
-       if (!thr_act)
-               return KERN_INVALID_ARGUMENT;
-       thread = act_lock_thread(thr_act);
-       switch (which) {
-               case THREAD_KERNEL_PORT:
-                       whichp = &thr_act->ith_sself;
-                       break;
-
-               default:
-                       act_unlock_thread(thr_act);
-                       return KERN_INVALID_ARGUMENT;
-       }
+       kern_return_t           result = KERN_SUCCESS;
 
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return KERN_FAILURE;
-       }
-
-       port = ipc_port_copy_send(*whichp);
-       act_unlock_thread(thr_act);
+       if (thread == THREAD_NULL)
+               return (KERN_INVALID_ARGUMENT);
 
-       *portp = port;
-       return KERN_SUCCESS;
-}
+       thread_mtx_lock(thread);
 
-/*
- *     Routine:        thread_set_special_port [kernel call]
- *     Purpose:
- *             Changes one of the thread's special ports,
- *             setting it to the supplied send right.
- *     Conditions:
- *             Nothing locked.  If successful, consumes
- *             the supplied send right.
- *     Returns:
- *             KERN_SUCCESS            Changed the special port.
- *             KERN_INVALID_ARGUMENT   The thread is null.
- *             KERN_FAILURE            The thread is dead.
- *             KERN_INVALID_ARGUMENT   Invalid special port.
- */
+       if (thread->active) {
+               if (thread != current_thread()) {
+                       thread_hold(thread);
 
-kern_return_t
-thread_set_special_port(
-       thread_act_t    thr_act,
-       int             which,
-       ipc_port_t      port)
-{
-       ipc_port_t      *whichp;
-       ipc_port_t      old;
-       thread_t        thread;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_PORT)
-               printf("thread_set_special_port(thr_act=%x,which=%x,port=%x\n",
-                       thr_act, which, port);
-#endif /* MACH_ASSERT */
-
-       if (thr_act == 0)
-               return KERN_INVALID_ARGUMENT;
-
-       thread = act_lock_thread(thr_act);
-       switch (which) {
-               case THREAD_KERNEL_PORT:
-                       whichp = &thr_act->ith_self;
-                       break;
+                       thread_mtx_unlock(thread);
 
-               default:
-                       act_unlock_thread(thr_act);
-                       return KERN_INVALID_ARGUMENT;
-       }
+                       if (thread_stop(thread)) {
+                               thread_mtx_lock(thread);
+                               result = machine_thread_get_state(
+                                                                               thread, flavor, state, state_count);
+                               thread_unstop(thread);
+                       }
+                       else {
+                               thread_mtx_lock(thread);
+                               result = KERN_ABORTED;
+                       }
 
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return KERN_FAILURE;
+                       thread_release(thread);
+               }
+               else
+                       result = machine_thread_get_state(
+                                                                       thread, flavor, state, state_count);
        }
+       else
+               result = KERN_TERMINATED;
 
-       old = *whichp;
-       *whichp = port;
-       act_unlock_thread(thr_act);
+       thread_mtx_unlock(thread);
 
-       if (IP_VALID(old))
-               ipc_port_release_send(old);
-       return KERN_SUCCESS;
+       return (result);
 }
 
 /*
- *  thread state should always be accessible by locking the thread
- *  and copying it.  The activation messes things up so for right
- *  now if it's not the top of the chain, use a special handler to
- *  get the information when the shuttle returns to the activation.
+ *     Change thread's machine-dependent state.  Called with nothing
+ *     locked.  Returns same way.
  */
 kern_return_t
-thread_get_state(
-       register thread_act_t   thr_act,
-       int                     flavor,
-       thread_state_t          state,  /* pointer to OUT array */
-       mach_msg_type_number_t  *state_count)   /*IN/OUT*/
+thread_set_state(
+       register thread_t               thread,
+       int                                             flavor,
+       thread_state_t                  state,
+       mach_msg_type_number_t  state_count)
 {
-       kern_return_t           ret;
-       thread_t                thread, nthread;
-
-#if 0 /* Grenoble - why?? */
-       if (thr_act == THR_ACT_NULL || thr_act == current_act())
-#else
-       if (thr_act == THR_ACT_NULL)
-#endif
+       kern_return_t           result = KERN_SUCCESS;
+
+       if (thread == THREAD_NULL)
                return (KERN_INVALID_ARGUMENT);
 
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return(KERN_TERMINATED);
-       }
+       thread_mtx_lock(thread);
 
-       thread_hold(thr_act);
-       while (1) {
-               if (!thread || thr_act != thread->top_act)
-                       break;
-               act_unlock_thread(thr_act);
-               (void)thread_stop_wait(thread);
-               nthread = act_lock_thread(thr_act);
-               if (nthread == thread)
-                       break;
-               thread_unstop(thread);
-               thread = nthread;
+       if (thread->active) {
+               if (thread != current_thread()) {
+                       thread_hold(thread);
+
+                       thread_mtx_unlock(thread);
+
+                       if (thread_stop(thread)) {
+                               thread_mtx_lock(thread);
+                               result = machine_thread_set_state(
+                                                                               thread, flavor, state, state_count);
+                               thread_unstop(thread);
+                       }
+                       else {
+                               thread_mtx_lock(thread);
+                               result = KERN_ABORTED;
+                       }
+
+                       thread_release(thread);
+               }
+               else
+                       result = machine_thread_set_state(
+                                                                       thread, flavor, state, state_count);
        }
-       ret = act_machine_get_state(thr_act, flavor,
-                                       state, state_count);
-       if (thread && thr_act == thread->top_act)
-           thread_unstop(thread);
-       thread_release(thr_act);
-       act_unlock_thread(thr_act);
-
-       return(ret);
-}
+       else
+               result = KERN_TERMINATED;
+
+       thread_mtx_unlock(thread);
 
+       return (result);
+}
 /*
- *     Change thread's machine-dependent state.  Called with nothing
- *     locked.  Returns same way.
+ * Kernel-internal "thread" interfaces used outside this file:
+ */
+
+/* Initialize (or re-initialize) a thread state.  Called from execve
+ * with nothing locked, returns same way.
  */
 kern_return_t
-thread_set_state(
-       register thread_act_t   thr_act,
-       int                     flavor,
-       thread_state_t          state,
-       mach_msg_type_number_t  state_count)
+thread_state_initialize(
+       register thread_t               thread)
 {
-       kern_return_t           ret;
-       thread_t                thread, nthread;
-
-#if 0 /* Grenoble - why?? */
-       if (thr_act == THR_ACT_NULL || thr_act == current_act())
-#else
-       if (thr_act == THR_ACT_NULL)
-#endif
+       kern_return_t           result = KERN_SUCCESS;
+
+       if (thread == THREAD_NULL)
                return (KERN_INVALID_ARGUMENT);
-       /*
-        * We have no kernel activations, so Utah's MO fails for signals etc.
-        *
-        * If we're blocked in the kernel, use non-blocking method, else
-        * pass locked thr_act+thread in to "normal" act_[gs]et_state().
-        */
 
-       thread = act_lock_thread(thr_act);
-       if (!thr_act->active) {
-               act_unlock_thread(thr_act);
-               return(KERN_TERMINATED);
-       }
+       thread_mtx_lock(thread);
 
-       thread_hold(thr_act);
-       while (1) {
-               if (!thread || thr_act != thread->top_act)
-                       break;
-               act_unlock_thread(thr_act);
-               (void)thread_stop_wait(thread);
-               nthread = act_lock_thread(thr_act);
-               if (nthread == thread)
-                       break;
-               thread_unstop(thread);
-               thread = nthread;
+       if (thread->active) {
+               if (thread != current_thread()) {
+                       thread_hold(thread);
+
+                       thread_mtx_unlock(thread);
+
+                       if (thread_stop(thread)) {
+                               thread_mtx_lock(thread);
+                               result = machine_thread_state_initialize( thread );
+                               thread_unstop(thread);
+                       }
+                       else {
+                               thread_mtx_lock(thread);
+                               result = KERN_ABORTED;
+                       }
+
+                       thread_release(thread);
+               }
+               else
+            result = machine_thread_state_initialize( thread );
        }
-       ret = act_machine_set_state(thr_act, flavor,
-                                       state, state_count);
-       if (thread && thr_act == thread->top_act)
-           thread_unstop(thread);
-       thread_release(thr_act);
-       act_unlock_thread(thr_act);
-
-       return(ret);
+       else
+               result = KERN_TERMINATED;
+
+       thread_mtx_unlock(thread);
+
+       return (result);
 }
 
-/*
- * Kernel-internal "thread" interfaces used outside this file:
- */
 
 kern_return_t
 thread_dup(
-       thread_act_t source_thr_act, 
-       thread_act_t target_thr_act)
+       register thread_t       target)
 {
-       kern_return_t           ret;
-       thread_t                thread, nthread;
+       thread_t                        self = current_thread();
+       kern_return_t           result = KERN_SUCCESS;
 
-       if (target_thr_act == THR_ACT_NULL || target_thr_act == current_act())
+       if (target == THREAD_NULL || target == self)
                return (KERN_INVALID_ARGUMENT);
 
-       thread = act_lock_thread(target_thr_act);
-       if (!target_thr_act->active) {
-               act_unlock_thread(target_thr_act);
-               return(KERN_TERMINATED);
-       }
+       thread_mtx_lock(target);
 
-       thread_hold(target_thr_act);
-       while (1) {
-               if (!thread || target_thr_act != thread->top_act)
-                       break;
-               act_unlock_thread(target_thr_act);
-               (void)thread_stop_wait(thread);
-               nthread = act_lock_thread(target_thr_act);
-               if (nthread == thread)
-                       break;
-               thread_unstop(thread);
-               thread = nthread;
+       if (target->active) {
+               thread_hold(target);
+
+               thread_mtx_unlock(target);
+
+               if (thread_stop(target)) {
+                       thread_mtx_lock(target);
+                       result = machine_thread_dup(self, target);
+                       thread_unstop(target);
+               }
+               else {
+                       thread_mtx_lock(target);
+                       result = KERN_ABORTED;
+               }
+
+               thread_release(target);
        }
-       ret = act_thread_dup(source_thr_act, target_thr_act);
-       if (thread && target_thr_act == thread->top_act)
-           thread_unstop(thread);
-       thread_release(target_thr_act);
-       act_unlock_thread(target_thr_act);
+       else
+               result = KERN_TERMINATED;
+
+       thread_mtx_unlock(target);
 
-       return(ret);
+       return (result);
 }
 
 
@@ -873,20 +584,13 @@ thread_dup(
  */
 kern_return_t
 thread_setstatus(
-       thread_act_t            thr_act,
-       int                     flavor,
-       thread_state_t          tstate,
+       register thread_t               thread,
+       int                                             flavor,
+       thread_state_t                  tstate,
        mach_msg_type_number_t  count)
 {
-       kern_return_t           kr;
-       thread_t                thread;
-
-       thread = act_lock_thread(thr_act);
-       assert(thread);
-       assert(thread->top_act == thr_act);
-       kr = act_machine_set_state(thr_act, flavor, tstate, count);
-       act_unlock_thread(thr_act);
-       return(kr);
+
+       return (thread_set_state(thread, flavor, tstate, count));
 }
 
 /*
@@ -896,839 +600,117 @@ thread_setstatus(
  */
 kern_return_t
 thread_getstatus(
-       thread_act_t            thr_act,
-       int                     flavor,
-       thread_state_t          tstate,
+       register thread_t               thread,
+       int                                             flavor,
+       thread_state_t                  tstate,
        mach_msg_type_number_t  *count)
 {
-       kern_return_t           kr;
-       thread_t                thread;
-
-       thread = act_lock_thread(thr_act);
-       assert(thread);
-       assert(thread->top_act == thr_act);
-       kr = act_machine_get_state(thr_act, flavor, tstate, count);
-       act_unlock_thread(thr_act);
-       return(kr);
+       return (thread_get_state(thread, flavor, tstate, count));
 }
 
 /*
- * Kernel-internal thread_activation interfaces used outside this file:
- */
-
-/*
- * act_init()  - Initialize activation handling code
+ * install_special_handler:
+ *
+ *     Install the special returnhandler that handles suspension and
+ *     termination, if it hasn't been installed already.
+ *
+ *     Called with the thread mutex held.
  */
 void
-act_init()
+install_special_handler(
+       thread_t                thread)
 {
-       thr_act_zone = zinit(
-                       sizeof(struct thread_activation),
-                       ACT_MAX * sizeof(struct thread_activation), /* XXX */
-                       ACT_CHUNK * sizeof(struct thread_activation),
-                       "activations");
-       act_machine_init();
-}
+       spl_t           s = splsched();
 
+       thread_lock(thread);
+       install_special_handler_locked(thread);
+       thread_unlock(thread);
+       splx(s);
+}
 
 /*
- * act_create  - Create a new activation in a specific task.
+ * install_special_handler_locked:
+ *
+ *     Do the work of installing the special_handler.
+ *
+ *     Called with the thread mutex and scheduling lock held.
  */
-kern_return_t
-act_create(task_t task,
-           thread_act_t *new_act)
+void
+install_special_handler_locked(
+       thread_t                                thread)
 {
-       thread_act_t thr_act;
-       int rc;
-       vm_map_t map;
-
-       thr_act = (thread_act_t)zalloc(thr_act_zone);
-       if (thr_act == 0)
-               return(KERN_RESOURCE_SHORTAGE);
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_LNK)
-               printf("act_create(task=%x,thr_act@%x=%x)\n",
-                       task, new_act, thr_act);
-#endif /* MACH_ASSERT */
-
-       /* Start by zeroing everything; then init non-zero items only */
-       bzero((char *)thr_act, sizeof(*thr_act));
-
-#ifdef MACH_BSD
-       {
-               /*
-                * Take care of the uthread allocation
-                * do it early in order to make KERN_RESOURCE_SHORTAGE
-                * handling trivial
-                * uthread_alloc() will bzero the storage allocated.
-                */
-               extern void *uthread_alloc(void);
-               thr_act->uthread = uthread_alloc();
-               if(thr_act->uthread == 0) {
-                       /* Put the thr_act back on the thr_act zone */
-                       zfree(thr_act_zone, (vm_offset_t)thr_act);
-                       return(KERN_RESOURCE_SHORTAGE);
-               }
-       }
-#endif /* MACH_BSD */
-
-       /*
-        * Start with one reference for the caller and one for the
-        * act being alive.
-        */
-       act_lock_init(thr_act);
-       thr_act->ref_count = 2;
-
-       /* Latch onto the task.  */
-       thr_act->task = task;
-       task_reference(task);
-
-       /* Initialize sigbufp for High-Watermark buffer allocation */
-        thr_act->r_sigbufp = (routine_descriptor_t) &thr_act->r_sigbuf;
-        thr_act->r_sigbuf_size = sizeof(thr_act->r_sigbuf);
-
-#if    THREAD_SWAPPER
-       thr_act->swap_state = TH_SW_IN;
-#if    MACH_ASSERT
-       thr_act->kernel_stack_swapped_in = TRUE;
-#endif /* MACH_ASSERT */
-#endif /* THREAD_SWAPPER */
+       ReturnHandler   **rh;
 
-       /* special_handler will always be last on the returnhandlers list.  */
-       thr_act->special_handler.next = 0;
-       thr_act->special_handler.handler = special_handler;
+       /* The work handler must always be the last ReturnHandler on the list,
+          because it can do tricky things like detach the thr_act.  */
+       for (rh = &thread->handlers; *rh; rh = &(*rh)->next)
+               continue;
 
-#if    MACH_PROF
-       thr_act->act_profiled = FALSE;
-       thr_act->act_profiled_own = FALSE;
-       thr_act->profil_buffer = NULLPROFDATA;
-#endif
+       if (rh != &thread->special_handler.next)
+               *rh = &thread->special_handler;
 
-       /* Initialize the held_ulocks queue as empty */
-       queue_init(&thr_act->held_ulocks);
+       /*
+        * Temporarily undepress, so target has
+        * a chance to do locking required to
+        * block itself in special_handler().
+        */
+       if (thread->sched_mode & TH_MODE_ISDEPRESSED)
+               compute_priority(thread, TRUE);
 
-       /* Inherit the profiling status of the parent task */
-       act_prof_init(thr_act, task);
+       thread_ast_set(thread, AST_APC);
 
-       ipc_thr_act_init(task, thr_act);
-       act_machine_create(task, thr_act);
+       if (thread == current_thread())
+               ast_propagate(thread->ast);
+       else {
+               processor_t             processor = thread->last_processor;
 
-       /*
-        * If thr_act created in kernel-loaded task, alter its saved
-        * state to so indicate
-        */
-       if (task->kernel_loaded) {
-               act_user_to_kernel(thr_act);
+               if (    processor != PROCESSOR_NULL                                     &&
+                               processor->state == PROCESSOR_RUNNING           &&
+                               processor->active_thread == thread                      )
+                       cause_ast_check(processor);
        }
-
-       /* Cache the task's map and take a reference to it */
-       map = task->map;
-       thr_act->map = map;
-
-       /* Inline vm_map_reference cause we don't want to increment res_count */
-       mutex_lock(&map->s_lock);
-#if    TASK_SWAPPER
-       assert(map->res_count > 0);
-       assert(map->ref_count >= map->res_count);
-#endif /* TASK_SWAPPER */
-       map->ref_count++;
-       mutex_unlock(&map->s_lock);
-
-       *new_act = thr_act;
-       return KERN_SUCCESS;
 }
 
 /*
- * act_free    - called when an thr_act's ref_count drops to zero.
- *
- * This can only happen after the activation has been reaped, and
- * all other references to it have gone away.  We can now release
- * the last critical resources, unlink the activation from the
- * task, and release the reference on the thread shuttle itself.
- *
- * Called with activation locked.
+ * Activation control support routines internal to this file:
  */
-#if    MACH_ASSERT
-int    dangerous_bzero = 1;    /* paranoia & safety */
-#endif
 
 void
-act_free(thread_act_t thr_act)
+act_execute_returnhandlers(void)
 {
-       task_t          task;
-       thread_t        thr;
-       vm_map_t        map;
-       unsigned int    ref;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_EXIT)
-               printf("act_free(%x(%d)) thr=%x tsk=%x(%d) pport=%x%sactive\n",
-                       thr_act, thr_act->ref_count, thr_act->thread,
-                       thr_act->task,
-                       thr_act->task ? thr_act->task->ref_count : 0,
-                       thr_act->pool_port,
-                       thr_act->active ? " " : " !");
-#endif /* MACH_ASSERT */
-
-
-#if    THREAD_SWAPPER
-       assert(thr_act->kernel_stack_swapped_in);
-#endif /* THREAD_SWAPPER */
-
-       assert(!thr_act->active);
-       assert(!thr_act->pool_port);
-
-       task = thr_act->task;
-       task_lock(task);
-
-       if (thr = thr_act->thread) {
-               time_value_t    user_time, system_time;
-
-               thread_read_times(thr, &user_time, &system_time);
-               time_value_add(&task->total_user_time, &user_time);
-               time_value_add(&task->total_system_time, &system_time);
-       
-               /* Unlink the thr_act from the task's thr_act list,
-                * so it doesn't appear in calls to task_threads and such.
-                * The thr_act still keeps its ref on the task, however.
-                */
-               queue_remove(&task->thr_acts, thr_act, thread_act_t, thr_acts);
-               thr_act->thr_acts.next = NULL;
-               task->thr_act_count--;
-
-#if     THREAD_SWAPPER
-               /*
-                * Thread is supposed to be unswappable by now...
-                */
-               assert(thr_act->swap_state == TH_SW_UNSWAPPABLE ||
-                      !thread_swap_unwire_stack);
-#endif  /* THREAD_SWAPPER */
-
-               task->res_act_count--;
-               task_unlock(task);
-               task_deallocate(task);
-               thread_deallocate(thr);
-               act_machine_destroy(thr_act);
-       } else {
-               /*
-                * Must have never really gotten started
-                * no unlinking from the task and no need
-                * to free the shuttle.
-                */
-               task_unlock(task);
-               task_deallocate(task);
-       }
+       thread_t        thread = current_thread();
 
-       sigbuf_dealloc(thr_act);
-       act_prof_deallocate(thr_act);
-       ipc_thr_act_terminate(thr_act);
+       thread_ast_clear(thread, AST_APC);
+       spllo();
 
-       /*
-        * Drop the cached map reference.
-        * Inline version of vm_map_deallocate() because we
-        * don't want to decrement the map's residence count here.
-        */
-       map = thr_act->map;
-       mutex_lock(&map->s_lock);
-#if    TASK_SWAPPER
-       assert(map->res_count >= 0);
-       assert(map->ref_count > map->res_count);
-#endif /* TASK_SWAPPER */
-       ref = --map->ref_count;
-       mutex_unlock(&map->s_lock);
-       if (ref == 0)
-               vm_map_destroy(map);
-
-#ifdef MACH_BSD 
-       {
-               /*
-                * Free uthread BEFORE the bzero.
-                * Not doing so will result in a leak.
-                */
-               extern void uthread_free(void *);
-               void *ut = thr_act->uthread;
-               thr_act->uthread = 0;
-               uthread_free(ut);
-       }
-#endif  /* MACH_BSD */   
-
-#if    MACH_ASSERT
-       if (dangerous_bzero)    /* dangerous if we're still using it! */
-               bzero((char *)thr_act, sizeof(*thr_act));
-#endif /* MACH_ASSERT */
-       /* Put the thr_act back on the thr_act zone */
-       zfree(thr_act_zone, (vm_offset_t)thr_act);
-}
+       for (;;) {
+               ReturnHandler   *rh;
 
+               thread_mtx_lock(thread);
 
-/*
- * act_attach  - Attach an thr_act to the top of a thread ("push the stack").
- *
- * The thread_shuttle must be either the current one or a brand-new one.
- * Assumes the thr_act is active but not in use, also, that if it is
- * attached to an thread_pool (i.e. the thread_pool pointer is nonzero),
- * the thr_act has already been taken off the thread_pool's list.
- *
- * Already locked: thr_act plus "appropriate" thread-related locks
- * (see act_lock_thread()).
- */
-void 
-act_attach(
-       thread_act_t    thr_act,
-       thread_t        thread,
-       unsigned        init_alert_mask)
-{
-        thread_act_t    lower;
-
-#if    MACH_ASSERT
-       assert(thread == current_thread() || thread->top_act == THR_ACT_NULL);
-       if (watchacts & WA_ACT_LNK)
-               printf("act_attach(thr_act %x(%d) thread %x(%d) mask %d)\n",
-                      thr_act, thr_act->ref_count, thread, thread->ref_count,
-                      init_alert_mask);
-#endif /* MACH_ASSERT */
-
-       /* 
-        *      Chain the thr_act onto the thread's thr_act stack.  
-        *      Set mask and auto-propagate alerts from below.
-        */
-       thr_act->ref_count++;
-       thr_act->thread = thread;
-       thr_act->higher = THR_ACT_NULL;  /*safety*/
-       thr_act->alerts = 0;
-       thr_act->alert_mask = init_alert_mask;
-       lower = thr_act->lower = thread->top_act;
-
-        if (lower != THR_ACT_NULL) {
-                lower->higher = thr_act;
-                thr_act->alerts = (lower->alerts & init_alert_mask);
-        }
-
-       thread->top_act = thr_act;
-}
+               (void)splsched();
+               thread_lock(thread);
 
-/*
- *     act_detach      
- *
- *     Remove the current thr_act from the top of the current thread, i.e.
- *     "pop the stack". Assumes already locked: thr_act plus "appropriate"
- *     thread-related locks (see act_lock_thread).
- */
-void 
-act_detach(
-       thread_act_t    cur_act)
-{
-       thread_t        cur_thread = cur_act->thread;
-
-#if    MACH_ASSERT
-       if (watchacts & (WA_EXIT|WA_ACT_LNK))
-               printf("act_detach: thr_act %x(%d), thrd %x(%d) task=%x(%d)\n",
-                      cur_act, cur_act->ref_count,
-                      cur_thread, cur_thread->ref_count,
-                      cur_act->task,
-                      cur_act->task ? cur_act->task->ref_count : 0);
-#endif /* MACH_ASSERT */
-
-       /* Unlink the thr_act from the thread's thr_act stack */
-       cur_thread->top_act = cur_act->lower;
-       cur_act->thread = 0;
-       cur_act->ref_count--;
-       assert(cur_act->ref_count > 0);
-
-       thread_pool_put_act(cur_act);
-
-#if    MACH_ASSERT
-       cur_act->lower = cur_act->higher = THR_ACT_NULL; 
-       if (cur_thread->top_act)
-               cur_thread->top_act->higher = THR_ACT_NULL;
-#endif /* MACH_ASSERT */
-
-       return;
-}
+               rh = thread->handlers;
+               if (rh != NULL) {
+                       thread->handlers = rh->next;
 
+                       thread_unlock(thread);
+                       spllo();
 
-/*
- * Synchronize a thread operation with RPC.  Called with nothing
- * locked.   Returns with thr_act locked, plus one of four
- * combinations of other locks held:
- *     none - for new activation not yet associated with thread_pool
- *             or shuttle
- *     rpc_lock(thr_act->thread) only - for base activation (one
- *             without pool_port)
- *     ip_lock(thr_act->pool_port) only - for empty activation (one
- *             with no associated shuttle)
- *     both locks - for "active" activation (has shuttle, lives
- *             on thread_pool)
- * If thr_act has an associated shuttle, this function returns
- * its address.  Otherwise it returns zero.
- */
-thread_t
-act_lock_thread(
-       thread_act_t thr_act)
-{
-       ipc_port_t pport;
+                       thread_mtx_unlock(thread);
 
-       /*
-        * Allow the shuttle cloning code (q.v., when it
-        * exists :-}) to obtain ip_lock()'s while holding
-        * an rpc_lock().
-        */
-       while (1) {
-               act_lock(thr_act);
-               pport = thr_act->pool_port;
-               if (!pport || ip_lock_try(pport)) {
-                       if (!thr_act->thread)
-                               break;
-                       if (rpc_lock_try(thr_act->thread))
-                               break;
-                       if (pport)
-                               ip_unlock(pport);
+                       /* Execute it */
+                       (*rh->handler)(rh, thread);
                }
-               act_unlock(thr_act);
-               mutex_pause();
-       }
-       return (thr_act->thread);
-}
-
-/*
- * Unsynchronize with RPC (i.e., undo an act_lock_thread() call).
- * Called with thr_act locked, plus thread locks held that are
- * "correct" for thr_act's state.  Returns with nothing locked.
- */
-void
-act_unlock_thread(thread_act_t thr_act)
-{
-       if (thr_act->thread)
-               rpc_unlock(thr_act->thread);
-       if (thr_act->pool_port)
-               ip_unlock(thr_act->pool_port);
-       act_unlock(thr_act);
-}
-
-/*
- * Synchronize with RPC given a pointer to a shuttle (instead of an
- * activation).  Called with nothing locked; returns with all
- * "appropriate" thread-related locks held (see act_lock_thread()).
- */
-thread_act_t
-thread_lock_act(
-       thread_t        thread)
-{
-       thread_act_t    thr_act;
-
-       while (1) {
-               rpc_lock(thread);
-               thr_act = thread->top_act;
-               if (!thr_act)
+               else
                        break;
-               if (!act_lock_try(thr_act)) {
-                       rpc_unlock(thread);
-                       mutex_pause();
-                       continue;
-               }
-               if (thr_act->pool_port &&
-                       !ip_lock_try(thr_act->pool_port)) {
-                       rpc_unlock(thread);
-                       act_unlock(thr_act);
-                       mutex_pause();
-                       continue;
-               }
-               break;
-       }
-       return (thr_act);
-}
-
-/*
- * Unsynchronize with RPC starting from a pointer to a shuttle.
- * Called with RPC-related locks held that are appropriate to
- * shuttle's state; any activation is also locked.
- */
-void
-thread_unlock_act(
-       thread_t        thread)
-{
-       thread_act_t    thr_act;
-
-       if (thr_act = thread->top_act) {
-               if (thr_act->pool_port)
-                       ip_unlock(thr_act->pool_port);
-               act_unlock(thr_act);
-       }
-       rpc_unlock(thread);
-}
-
-/*
- * switch_act
- *
- * If a new activation is given, switch to it. If not,
- * switch to the lower activation (pop). Returns the old
- * activation. This is for RPC support.
- */
-thread_act_t
-switch_act( 
-       thread_act_t act)
-{
-       thread_t        thread;
-       thread_act_t    old, new;
-       unsigned        cpu;
-       spl_t           spl;
-
-
-       disable_preemption();
-
-       cpu = cpu_number();
-       thread  = current_thread();
-
-       /*
-        *      Find the old and new activation for switch.
-        */
-       old = thread->top_act;
-
-       if (act) {
-               new = act;
-                new->thread = thread;
-       }
-       else {
-               new = old->lower;
        }
 
-       assert(new != THR_ACT_NULL);
-#if    THREAD_SWAPPER
-       assert(new->swap_state != TH_SW_OUT &&
-              new->swap_state != TH_SW_COMING_IN);
-#endif /* THREAD_SWAPPER */
-
-        assert(cpu_data[cpu].active_thread == thread);
-       active_kloaded[cpu] = (new->kernel_loaded) ? new : 0;
-
-       /* This is where all the work happens */
-       machine_switch_act(thread, old, new, cpu);
-
-       /*
-        *      Push or pop an activation on the chain.
-        */
-       if (act) {
-               act_attach(new, thread, 0);
-       }
-       else {
-               act_detach(old);
-       }
-
-        enable_preemption();
-
-       return(old);
-}
-
-/*
- * install_special_handler
- *     Install the special returnhandler that handles suspension and
- *     termination, if it hasn't been installed already.
- *
- * Already locked: RPC-related locks for thr_act, but not
- * scheduling lock (thread_lock()) of the associated thread.
- */
-void
-install_special_handler(
-       thread_act_t    thr_act)
-{
-       spl_t           spl;
-       thread_t        thread = thr_act->thread;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-           printf("act_%x: install_special_hdlr(%x)\n",current_act(),thr_act);
-#endif /* MACH_ASSERT */
-
-       spl = splsched();
-       thread_lock(thread);
-       install_special_handler_locked(thr_act);
        thread_unlock(thread);
-       splx(spl);
-}
-
-/*
- * install_special_handler_locked
- *     Do the work of installing the special_handler.
- *
- * Already locked: RPC-related locks for thr_act, plus the
- * scheduling lock (thread_lock()) of the associated thread.
- */
-void
-install_special_handler_locked(
-       thread_act_t    thr_act)
-{
-       ReturnHandler   **rh;
-       thread_t        thread = thr_act->thread;
-
-       /* The work handler must always be the last ReturnHandler on the list,
-          because it can do tricky things like detach the thr_act.  */
-       for (rh = &thr_act->handlers; *rh; rh = &(*rh)->next)
-               /* */ ;
-       if (rh != &thr_act->special_handler.next) {
-               *rh = &thr_act->special_handler;
-       }
-       if (thread && thr_act == thread->top_act) {
-               /*
-                * Temporarily undepress, so target has
-                * a chance to do locking required to
-                * block itself in special_handler().
-                */
-               if (thread->depress_priority >= 0) {
-                       thread->priority = thread->depress_priority;
-
-                       /*
-                        * Use special value -2 to indicate need
-                        * to redepress priority in special_handler
-                        * as thread blocks
-                        */
-                       thread->depress_priority = -2;
-                       compute_priority(thread, FALSE);
-               }       
-       }
-       act_set_apc(thr_act);
-}
-
-/*
- * JMM -
- * These two routines will be enhanced over time to call the general handler registration
- * mechanism used by special handlers and alerts.  They are hack in for now to avoid
- * having to export the gory details of ASTs to the BSD code right now.
- */
-extern thread_apc_handler_t bsd_ast;
-
-kern_return_t
-thread_apc_set(
-       thread_act_t thr_act,
-       thread_apc_handler_t apc)
-{
-       assert(apc == bsd_ast);
-       thread_ast_set(thr_act, AST_BSD);
-       if (thr_act == current_act())
-               ast_propagate(thr_act->ast);
-       return KERN_SUCCESS;
-}
-
-kern_return_t
-thread_apc_clear(
-       thread_act_t thr_act,
-       thread_apc_handler_t apc)
-{
-       assert(apc == bsd_ast);
-       thread_ast_clear(thr_act, AST_BSD);
-       if (thr_act == current_act())
-               ast_off(AST_BSD);
-       return KERN_SUCCESS;
-}
-
-/*
- * act_set_thread_pool - Assign an activation to a specific thread_pool.
- * Fails if the activation is already assigned to another pool.
- * If thread_pool == 0, we remove the thr_act from its thread_pool.
- *
- * Called the port containing thread_pool already locked.
- * Returns the same way.
- */
-kern_return_t act_set_thread_pool(
-       thread_act_t    thr_act,
-       ipc_port_t      pool_port)
-{
-       thread_pool_t   thread_pool;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_LNK)
-               printf("act_set_thread_pool: %x(%d) -> %x\n",
-                       thr_act, thr_act->ref_count, thread_pool);
-#endif /* MACH_ASSERT */
-
-       if (pool_port == 0) {
-               thread_act_t *lact;
-
-               if (thr_act->pool_port == 0)
-                       return KERN_SUCCESS;
-               thread_pool = &thr_act->pool_port->ip_thread_pool;
-
-               for (lact = &thread_pool->thr_acts; *lact;
-                                       lact = &((*lact)->thread_pool_next)) {
-                       if (thr_act == *lact) {
-                               *lact = thr_act->thread_pool_next;
-                               break;
-                       }
-               }
-               act_lock(thr_act);
-               thr_act->pool_port = 0;
-               thr_act->thread_pool_next = 0;
-               act_unlock(thr_act);
-               act_deallocate(thr_act);
-               return KERN_SUCCESS;
-       }
-       if (thr_act->pool_port != pool_port) {
-               thread_pool = &pool_port->ip_thread_pool;
-               if (thr_act->pool_port != 0) {
-#if    MACH_ASSERT
-                       if (watchacts & WA_ACT_LNK)
-                           printf("act_set_thread_pool found %x!\n",
-                                                       thr_act->pool_port);
-#endif /* MACH_ASSERT */
-                       return(KERN_FAILURE);
-               }
-               act_lock(thr_act);
-               thr_act->pool_port = pool_port;
-
-               /* The pool gets a ref to the activation -- have
-                * to inline operation because thr_act is already
-                * locked.
-                */
-               act_locked_act_reference(thr_act);
-
-               /* If it is available,
-                * add it to the thread_pool's available-activation list.
-                */
-               if ((thr_act->thread == 0) && (thr_act->suspend_count == 0)) {
-                       thr_act->thread_pool_next = thread_pool->thr_acts;
-                       pool_port->ip_thread_pool.thr_acts = thr_act;
-                       if (thread_pool->waiting)
-                               thread_pool_wakeup(thread_pool);
-               }
-               act_unlock(thr_act);
-       }
-
-       return KERN_SUCCESS;
-}
-
-/*
- * act_locked_act_set_thread_pool- Assign activation to a specific thread_pool.
- * Fails if the activation is already assigned to another pool.
- * If thread_pool == 0, we remove the thr_act from its thread_pool.
- *
- * Called the port containing thread_pool already locked.
- * Also called with the thread activation locked.
- * Returns the same way.
- *
- * This routine is the same as `act_set_thread_pool()' except that it does
- * not call `act_deallocate(),' which unconditionally tries to obtain the
- * thread activation lock.
- */
-kern_return_t act_locked_act_set_thread_pool(
-       thread_act_t    thr_act,
-       ipc_port_t      pool_port)
-{
-       thread_pool_t   thread_pool;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_LNK)
-               printf("act_set_thread_pool: %x(%d) -> %x\n",
-                       thr_act, thr_act->ref_count, thread_pool);
-#endif /* MACH_ASSERT */
-
-       if (pool_port == 0) {
-               thread_act_t *lact;
-
-               if (thr_act->pool_port == 0)
-                       return KERN_SUCCESS;
-               thread_pool = &thr_act->pool_port->ip_thread_pool;
-
-               for (lact = &thread_pool->thr_acts; *lact;
-                                       lact = &((*lact)->thread_pool_next)) {
-                       if (thr_act == *lact) {
-                               *lact = thr_act->thread_pool_next;
-                               break;
-                       }
-               }
-
-               thr_act->pool_port = 0;
-               thr_act->thread_pool_next = 0;
-               act_locked_act_deallocate(thr_act);
-               return KERN_SUCCESS;
-       }
-       if (thr_act->pool_port != pool_port) {
-               thread_pool = &pool_port->ip_thread_pool;
-               if (thr_act->pool_port != 0) {
-#if    MACH_ASSERT
-                       if (watchacts & WA_ACT_LNK)
-                           printf("act_set_thread_pool found %x!\n",
-                                                       thr_act->pool_port);
-#endif /* MACH_ASSERT */
-                       return(KERN_FAILURE);
-               }
-               thr_act->pool_port = pool_port;
-
-               /* The pool gets a ref to the activation -- have
-                * to inline operation because thr_act is already
-                * locked.
-                */
-               act_locked_act_reference(thr_act);
-
-               /* If it is available,
-                * add it to the thread_pool's available-activation list.
-                */
-               if ((thr_act->thread == 0) && (thr_act->suspend_count == 0)) {
-                       thr_act->thread_pool_next = thread_pool->thr_acts;
-                       pool_port->ip_thread_pool.thr_acts = thr_act;
-                       if (thread_pool->waiting)
-                               thread_pool_wakeup(thread_pool);
-               }
-       }
-
-       return KERN_SUCCESS;
-}
-
-/*
- * Activation control support routines internal to this file:
- */
-
-/*
- * act_execute_returnhandlers()        - does just what the name says
- *
- * This is called by system-dependent code when it detects that
- * thr_act->handlers is non-null while returning into user mode.
- * Activations linked onto an thread_pool always have null thr_act->handlers,
- * so RPC entry paths need not check it.
- */
-void act_execute_returnhandlers(
-       void)
-{
-       spl_t           s;
-       thread_t        thread;
-       thread_act_t    thr_act = current_act();
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-               printf("execute_rtn_hdlrs: thr_act=%x\n", thr_act);
-#endif /* MACH_ASSERT */
-
-       s = splsched();
-       act_clr_apc(thr_act);
        spllo();
-       while (1) {
-               ReturnHandler *rh;
 
-               /* Grab the next returnhandler */
-               thread = act_lock_thread(thr_act);
-               (void)splsched();
-               thread_lock(thread);
-               rh = thr_act->handlers;
-               if (!rh) {
-                       thread_unlock(thread);
-                       splx(s);
-                       act_unlock_thread(thr_act);
-                       return;
-               }
-               thr_act->handlers = rh->next;
-               thread_unlock(thread);
-               spllo();
-               act_unlock_thread(thr_act);
-
-#if    MACH_ASSERT
-               if (watchacts & WA_ACT_HDLR)
-                   printf( (rh == &thr_act->special_handler) ?
-                       "\tspecial_handler\n" : "\thandler=%x\n",
-                                   rh->handler);
-#endif /* MACH_ASSERT */
-
-               /* Execute it */
-               (*rh->handler)(rh, thr_act);
-       }
+       thread_mtx_unlock(thread);
 }
 
 /*
@@ -1743,28 +725,31 @@ void act_execute_returnhandlers(
 void
 special_handler_continue(void)
 {
-       thread_act_t cur_act = current_act();
-       thread_t thread = cur_act->thread;
-       spl_t s;
+       thread_t                thread = current_thread();
+
+       thread_mtx_lock(thread);
 
-       if (cur_act->suspend_count)
-               install_special_handler(cur_act);
+       if (thread->suspend_count > 0)
+               install_special_handler(thread);
        else {
-               s = splsched();
+               spl_t                   s = splsched();
+
                thread_lock(thread);
-               if (thread->depress_priority == -2) {
-                       /*
-                        * We were temporarily undepressed by
-                        * install_special_handler; restore priority
-                        * depression.
-                        */
-                       thread->depress_priority = thread->priority;
-                       thread->priority = thread->sched_pri = DEPRESSPRI;
+               if (thread->sched_mode & TH_MODE_ISDEPRESSED) {
+                       processor_t             myprocessor = thread->last_processor;
+
+                       thread->sched_pri = DEPRESSPRI;
+                       myprocessor->current_pri = thread->sched_pri;
+                       thread->sched_mode &= ~TH_MODE_PREEMPT;
                }
                thread_unlock(thread);
                splx(s);
        }
+
+       thread_mtx_unlock(thread);
+
        thread_exception_return();
+       /*NOTREACHED*/
 }
 
 /*
@@ -1773,526 +758,122 @@ special_handler_continue(void)
  */
 void
 special_handler(
-       ReturnHandler   *rh,
-       thread_act_t    cur_act)
+       __unused ReturnHandler  *rh,
+       thread_t                                thread)
 {
        spl_t           s;
-       thread_t        lthread;
-       thread_t        thread = act_lock_thread(cur_act);
-       unsigned        alert_bits;
-       exception_data_type_t
-                       codes[EXCEPTION_CODE_MAX];
-       kern_return_t   kr;
-       kern_return_t   exc_kr;
-
-       assert(thread != THREAD_NULL);
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-           printf("\t\tspecial_handler(thr_act=%x(%d))\n", cur_act,
-                               (cur_act ? cur_act->ref_count : 0));
-#endif /* MACH_ASSERT */
 
-       s = splsched();
+       thread_mtx_lock(thread);
 
+       s = splsched();
        thread_lock(thread);
-       thread->state &= ~TH_ABORT;     /* clear any aborts */
+       thread->state &= ~(TH_ABORT|TH_ABORT_SAFELY);   /* clear any aborts */
        thread_unlock(thread);
        splx(s);
 
-       /*
-        * If someone has killed this invocation,
-        * invoke the return path with a terminated exception.
-        */
-       if (!cur_act->active) {
-               act_unlock_thread(cur_act);
-               act_machine_return(KERN_TERMINATED);
-       }
-
-#ifdef CALLOUT_RPC_MODEL
-       /*
-        * JMM - We don't intend to support this RPC model in Darwin.
-        * We will support inheritance through chains of activations
-        * on shuttles, but it will be universal and not just for RPC.
-        * As such, each activation will always have a base shuttle.
-        * Our RPC model will probably even support the notion of
-        * alerts (thrown up the chain of activations to affect the
-        * work done on our behalf), but the unlinking of the shuttles
-        * will be completely difference because we will never have
-        * to clone them.
-        */
-
-       /* strip server terminated bit */
-       alert_bits = cur_act->alerts & (~SERVER_TERMINATED);
-
-       /* clear server terminated bit */
-       cur_act->alerts &= ~SERVER_TERMINATED;
-
-       if ( alert_bits ) {
-               /*
-                * currently necessary to coordinate with the exception 
-                * code -fdr
-                */
-               act_unlock_thread(cur_act);
-
-               /* upcall exception/alert port */
-               codes[0] = alert_bits;
-
-               /*
-                * Exception makes a lot of assumptions. If there is no
-                * exception handler or the exception reply is broken, the 
-                * thread will be terminated and exception will not return. If
-                * we decide we don't like that behavior, we need to check
-                * for the existence of an exception port before we call 
-                * exception.
-                */
-               exc_kr = exception( EXC_RPC_ALERT, codes, 1 );
-
-               /* clear the orphaned and time constraint indications */
-               cur_act->alerts &= ~(ORPHANED | TIME_CONSTRAINT_UNSATISFIED);
-
-               /* if this orphaned activation should be terminated... */
-               if (exc_kr == KERN_RPC_TERMINATE_ORPHAN) {
-                       /*
-                        * ... terminate the activation
-                        *
-                        * This is done in two steps.  First, the activation is
-                        * disabled (prepared for termination); second, the
-                        * `special_handler()' is executed again -- this time
-                        * to terminate the activation.
-                        * (`act_disable_task_locked()' arranges for the
-                        * additional execution of the `special_handler().')
-                        */
-
-#if    THREAD_SWAPPER
-                       thread_swap_disable(cur_act);
-#endif /* THREAD_SWAPPER */
-
-                       /* acquire appropriate locks */
-                       task_lock(cur_act->task);
-                       act_lock_thread(cur_act);
-
-                       /* detach the activation from its task */
-                       kr = act_disable_task_locked(cur_act);
-                       assert( kr == KERN_SUCCESS );
-
-                       /* release locks */
-                       task_unlock(cur_act->task);
-               }
-               else {
-                       /* acquire activation lock again (released below) */
-                       act_lock_thread(cur_act);
-                       s = splsched();
-                       thread_lock(thread);
-                       if (thread->depress_priority == -2) {
-                               /*
-                                * We were temporarily undepressed by
-                                * install_special_handler; restore priority
-                                * depression.
-                                */
-                               thread->depress_priority = thread->priority;
-                               thread->priority = thread->sched_pri = DEPRESSPRI;
-                       }
-                       thread_unlock(thread);
-                       splx(s);
-               }
-       }
-#endif /* CALLOUT_RPC_MODEL */
-
        /*
         * If we're suspended, go to sleep and wait for someone to wake us up.
         */
-       if (cur_act->suspend_count) {
-               if( cur_act->handlers == NULL ) {
-                       assert_wait((event_t)&cur_act->suspend_count,
-                                   THREAD_ABORTSAFE);
-                       act_unlock_thread(cur_act);
-                       thread_block(special_handler_continue);
-                       /* NOTREACHED */
-               }
-               special_handler_continue();
-       }
-
-       act_unlock_thread(cur_act);
-}
-
-/*
- * Try to nudge a thr_act into executing its returnhandler chain.
- * Ensures that the activation will execute its returnhandlers
- * before it next executes any of its user-level code.
- *
- * Called with thr_act's act_lock() and "appropriate" thread-related
- * locks held.  (See act_lock_thread().)  Returns same way.
- */
-void
-nudge(thread_act_t     thr_act)
-{
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-           printf("\tact_%x: nudge(%x)\n", current_act(), thr_act);
-#endif /* MACH_ASSERT */
-
-       /*
-        * Don't need to do anything at all if this thr_act isn't the topmost.
-        */
-       if (thr_act->thread && thr_act->thread->top_act == thr_act) {
-               /*
-                * If it's suspended, wake it up. 
-                * This should nudge it even on another CPU.
-                */
-               thread_wakeup((event_t)&thr_act->suspend_count);
-       }
-}
-
-/*
- * Update activation that belongs to a task created via kernel_task_create().
- */
-void
-act_user_to_kernel(
-       thread_act_t    thr_act)
-{
-       pcb_user_to_kernel(thr_act);
-       thr_act->kernel_loading = TRUE;
-}
-
-/*
- * Already locked: thr_act->task, RPC-related locks for thr_act
- *
- * Detach an activation from its task, and prepare it to terminate
- * itself.
- */
-kern_return_t
-act_disable_task_locked(
-       thread_act_t    thr_act)
-{
-       thread_t        thread = thr_act->thread;
-       task_t          task = thr_act->task;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_EXIT) {
-               printf("act_%x: act_disable_tl(thr_act=%x(%d))%sactive task=%x(%d)",
-                              current_act(), thr_act, thr_act->ref_count,
-                              (thr_act->active ? " " : " !"),
-                              thr_act->task, thr_act->task? thr_act->task->ref_count : 0);
-               if (thr_act->pool_port)
-                       printf(", pool_port %x", thr_act->pool_port);
-               printf("\n");
-               (void) dump_act(thr_act);
-       }
-#endif /* MACH_ASSERT */
-
-       /* This will allow no more control ops on this thr_act. */
-       thr_act->active = 0;
-       ipc_thr_act_disable(thr_act);
-
-       /* Clean-up any ulocks that are still owned by the thread
-        * activation (acquired but not released or handed-off).
-        */
-       act_ulock_release_all(thr_act);
-
-       /* When the special_handler gets executed,
-        * it will see the terminated condition and exit
-        * immediately.
-        */
-       install_special_handler(thr_act);
-
-
-       /* If the target happens to be suspended,
-        * give it a nudge so it can exit.
-        */
-       if (thr_act->suspend_count)
-               nudge(thr_act);
+       if (thread->active) {
+               if (thread->suspend_count > 0) {
+                       if (thread->handlers == NULL) {
+                               assert_wait(&thread->suspend_count, THREAD_ABORTSAFE);
+                               thread_mtx_unlock(thread);
+                               thread_block((thread_continue_t)special_handler_continue);
+                               /*NOTREACHED*/
+                       }
 
-       /* Drop the thr_act reference taken for being active.
-        * (There is still at least one reference left:
-        * the one we were passed.)
-        * Inline the deallocate because thr_act is locked.
-        */
-       act_locked_act_deallocate(thr_act);
+                       thread_mtx_unlock(thread);
 
-       return(KERN_SUCCESS);
-}
-
-/*
- * act_alert   - Register an alert from this activation.
- *
- * Each set bit is propagated upward from (but not including) this activation,
- * until the top of the chain is reached or the bit is masked.
- */
-kern_return_t
-act_alert(thread_act_t thr_act, unsigned alerts)
-{
-       thread_t thread = act_lock_thread(thr_act);
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_LNK)
-               printf("act_alert %x: %x\n", thr_act, alerts);
-#endif /* MACH_ASSERT */
-
-       if (thread) {
-               thread_act_t act_up = thr_act;
-               while ((alerts) && (act_up != thread->top_act)) {
-                       act_up = act_up->higher;
-                       alerts &= act_up->alert_mask;
-                       act_up->alerts |= alerts;
+                       special_handler_continue();
+                       /*NOTREACHED*/
                }
-               /*
-                * XXXX If we reach the top, and it is blocked in glue
-                * code, do something to kick it.  XXXX
-                */
-       }
-       act_unlock_thread(thr_act);
-
-       return KERN_SUCCESS;
-}
-
-kern_return_t act_alert_mask(thread_act_t thr_act, unsigned alert_mask)
-{
-       panic("act_alert_mask NOT YET IMPLEMENTED\n");
-       return KERN_SUCCESS;
-}
-
-typedef struct GetSetState {
-       struct ReturnHandler rh;
-       int flavor;
-       void *state;
-       int *pcount;
-       int result;
-} GetSetState;
-
-/* Local Forward decls */
-kern_return_t get_set_state(
-                       thread_act_t thr_act, int flavor,
-                       thread_state_t state, int *pcount,
-                       void (*handler)(ReturnHandler *rh, thread_act_t thr_act));
-void get_state_handler(ReturnHandler *rh, thread_act_t thr_act);
-void set_state_handler(ReturnHandler *rh, thread_act_t thr_act);
-
-/*
- * get_set_state(thr_act ...)
- *
- * General code to install g/set_state handler.
- * Called with thr_act's act_lock() and "appropriate"
- * thread-related locks held.  (See act_lock_thread().)
- */
-kern_return_t
-get_set_state(thread_act_t thr_act, int flavor, thread_state_t state, int *pcount,
-                       void (*handler)(ReturnHandler *rh, thread_act_t thr_act))
-{
-       GetSetState gss;
-       spl_t s;
-
-       /* Initialize a small parameter structure */
-       gss.rh.handler = handler;
-       gss.flavor = flavor;
-       gss.state = state;
-       gss.pcount = pcount;
-       gss.result = KERN_ABORTED;      /* iff wait below is interrupted */
-
-       /* Add it to the thr_act's return handler list */
-       gss.rh.next = thr_act->handlers;
-       thr_act->handlers = &gss.rh;
-
-       s = splsched();
-       act_set_apc(thr_act);
-       splx(s);
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR) {
-           printf("act_%x: get_set_state(thr_act=%x flv=%x state=%x ptr@%x=%x)",
-                   current_act(), thr_act, flavor, state,
-                   pcount, (pcount ? *pcount : 0));
-           printf((handler == get_state_handler ? "get_state_hdlr\n" :
-                   (handler == set_state_handler ? "set_state_hdlr\n" :
-                       "hndler=%x\n")), handler); 
        }
-#endif /* MACH_ASSERT */
+       else {
+               thread_mtx_unlock(thread);
 
-       assert(thr_act->thread);        /* Callers must ensure these */
-       assert(thr_act != current_act());
-       for (;;) {
-               nudge(thr_act);
-               /*
-                * Wait must be interruptible to avoid deadlock (e.g.) with
-                * task_suspend() when caller and target of get_set_state()
-                * are in same task.
-                */
-               assert_wait((event_t)&gss, THREAD_ABORTSAFE);
-               act_unlock_thread(thr_act);
-               thread_block((void (*)(void))0);
-               if (gss.result != KERN_ABORTED)
-                       break;
-               if (current_act()->handlers)
-                       act_execute_returnhandlers();
-               act_lock_thread(thr_act);
+               thread_terminate_self();
+               /*NOTREACHED*/
        }
 
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-           printf("act_%x: get_set_state returns %x\n",
-                           current_act(), gss.result);
-#endif /* MACH_ASSERT */
-
-       return gss.result;
-}
-
-void
-set_state_handler(ReturnHandler *rh, thread_act_t thr_act)
-{
-       GetSetState *gss = (GetSetState*)rh;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-               printf("act_%x: set_state_handler(rh=%x,thr_act=%x)\n",
-                       current_act(), rh, thr_act);
-#endif /* MACH_ASSERT */
-
-       gss->result = act_machine_set_state(thr_act, gss->flavor,
-                                               gss->state, *gss->pcount);
-       thread_wakeup((event_t)gss);
-}
-
-void
-get_state_handler(ReturnHandler *rh, thread_act_t thr_act)
-{
-       GetSetState *gss = (GetSetState*)rh;
-
-#if    MACH_ASSERT
-       if (watchacts & WA_ACT_HDLR)
-               printf("act_%x: get_state_handler(rh=%x,thr_act=%x)\n",
-                       current_act(), rh, thr_act);
-#endif /* MACH_ASSERT */
-
-       gss->result = act_machine_get_state(thr_act, gss->flavor,
-                       gss->state, 
-                       (mach_msg_type_number_t *) gss->pcount);
-       thread_wakeup((event_t)gss);
-}
-
-kern_return_t
-act_get_state_locked(thread_act_t thr_act, int flavor, thread_state_t state,
-                                       mach_msg_type_number_t *pcount)
-{
-#if    MACH_ASSERT
-    if (watchacts & WA_ACT_HDLR)
-       printf("act_%x: act_get_state_L(thr_act=%x,flav=%x,st=%x,pcnt@%x=%x)\n",
-               current_act(), thr_act, flavor, state, pcount,
-               (pcount? *pcount : 0));
-#endif /* MACH_ASSERT */
-
-    return(get_set_state(thr_act, flavor, state, (int*)pcount, get_state_handler));
+       thread_mtx_unlock(thread);
 }
 
 kern_return_t
-act_set_state_locked(thread_act_t thr_act, int flavor, thread_state_t state,
-                                       mach_msg_type_number_t count)
-{
-#if    MACH_ASSERT
-    if (watchacts & WA_ACT_HDLR)
-       printf("act_%x: act_set_state_L(thr_act=%x,flav=%x,st=%x,pcnt@%x=%x)\n",
-               current_act(), thr_act, flavor, state, count, count);
-#endif /* MACH_ASSERT */
-
-    return(get_set_state(thr_act, flavor, state, (int*)&count, set_state_handler));
-}
-
-kern_return_t
-act_set_state(thread_act_t thr_act, int flavor, thread_state_t state,
-                                       mach_msg_type_number_t count)
+act_set_state(
+       thread_t                                thread,
+       int                                             flavor,
+       thread_state_t                  state,
+       mach_msg_type_number_t  count)
 {
-    if (thr_act == THR_ACT_NULL || thr_act == current_act())
-           return(KERN_INVALID_ARGUMENT);
+    if (thread == current_thread())
+           return (KERN_INVALID_ARGUMENT);
 
-    act_lock_thread(thr_act);
-    return(act_set_state_locked(thr_act, flavor, state, count));
+    return (thread_set_state(thread, flavor, state, count));
     
 }
 
 kern_return_t
-act_get_state(thread_act_t thr_act, int flavor, thread_state_t state,
-                                       mach_msg_type_number_t *pcount)
+act_get_state(
+       thread_t                                thread,
+       int                                             flavor,
+       thread_state_t                  state,
+       mach_msg_type_number_t  *count)
 {
-    if (thr_act == THR_ACT_NULL || thr_act == current_act())
-           return(KERN_INVALID_ARGUMENT);
+    if (thread == current_thread())
+           return (KERN_INVALID_ARGUMENT);
 
-    act_lock_thread(thr_act);
-    return(act_get_state_locked(thr_act, flavor, state, pcount));
+    return (thread_get_state(thread, flavor, state, count));
 }
 
-/*
- * These two should be called at splsched()
- * Set/clear indicator to run APC (layered on ASTs)
- */
 void
-act_set_apc(thread_act_t thr_act)
+act_set_astbsd(
+       thread_t        thread)
 {
-       thread_ast_set(thr_act, AST_APC);
-       if (thr_act == current_act()) {
-               mp_disable_preemption();
-               ast_propagate(thr_act->ast);
-               mp_enable_preemption();
+       spl_t           s = splsched();
+       
+       if (thread == current_thread()) {
+               thread_ast_set(thread, AST_BSD);
+               ast_propagate(thread->ast);
        }
-}
-
-void
-act_clr_apc(thread_act_t thr_act)
-{
-       thread_ast_clear(thr_act, AST_APC);
-}
-
-void
-act_ulock_release_all(thread_act_t thr_act)
-{
-       ulock_t ulock;
+       else {
+               processor_t             processor;
 
-       while (!queue_empty(&thr_act->held_ulocks)) {
-               ulock = (ulock_t) queue_first(&thr_act->held_ulocks);
-               (void) lock_make_unstable(ulock, thr_act);
-               (void) lock_release_internal(ulock, thr_act);
+               thread_lock(thread);
+               thread_ast_set(thread, AST_BSD);
+               processor = thread->last_processor;
+               if (    processor != PROCESSOR_NULL                                     &&
+                               processor->state == PROCESSOR_RUNNING           &&
+                               processor->active_thread == thread                      )
+                       cause_ast_check(processor);
+               thread_unlock(thread);
        }
+       
+       splx(s);
 }
 
-/*
- * Provide routines (for export to other components) of things that
- * are implemented as macros insternally.
- */
-#undef current_act
-thread_act_t
-current_act(void)
-{
-       return(current_act_fast());
-}
-
-thread_act_t
-thread_self(void)
-{
-       thread_act_t self = current_act_fast();
-
-       act_reference(self);
-       return self;
-}
-
-thread_act_t
-mach_thread_self(void)
-{
-       thread_act_t self = current_act_fast();
-
-       act_reference(self);
-       return self;
-}
-
-#undef act_reference
 void
-act_reference(
-       thread_act_t thr_act)
+act_set_apc(
+       thread_t        thread)
 {
-       act_reference_fast(thr_act);
-}
+       spl_t           s = splsched();
+       
+       if (thread == current_thread()) {
+               thread_ast_set(thread, AST_APC);
+               ast_propagate(thread->ast);
+       }
+       else {
+               processor_t             processor;
 
-#undef act_deallocate
-void
-act_deallocate(
-       thread_act_t thr_act) 
-{
-       act_deallocate_fast(thr_act);
+               thread_lock(thread);
+               thread_ast_set(thread, AST_APC);
+               processor = thread->last_processor;
+               if (    processor != PROCESSOR_NULL                                     &&
+                               processor->state == PROCESSOR_RUNNING           &&
+                               processor->active_thread == thread                      )
+                       cause_ast_check(processor);
+               thread_unlock(thread);
+       }
+       
+       splx(s);
 }
-