xnu-1228.tar.gz

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

diff --git a/osfmk/kern/thread.h b/osfmk/kern/thread.h
index bca2bc841c0f52f0babb6efefd302282c41e6c43..8387019b8cf9db2c7baa8fe79c871b849c1b91cb 100644 (file)
--- a/osfmk/kern/thread.h
+++ b/osfmk/kern/thread.h
@@ -1,23 +1,29 @@
 /*
 /*

- * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2007 Apple Inc. All rights reserved.

  *
  *

- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

  * 
  * 

- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This 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.

  * 
  * 

- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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,
  * 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.
+ * 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_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@

  */
 /*
  * @OSF_FREE_COPYRIGHT@
  */
 /*
  * @OSF_FREE_COPYRIGHT@


@@ -96,8 +102,6 @@
 #include <cputypes.h>
 
 #include <mach_assert.h>
 #include <cputypes.h>
 
 #include <mach_assert.h>

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

 #include <mach_ldebug.h>
 
 #include <ipc/ipc_types.h>
 #include <mach_ldebug.h>
 
 #include <ipc/ipc_types.h>


@@ -114,6 +118,7 @@
 #include <kern/timer_call.h>
 #include <kern/task.h>
 #include <kern/exception.h>
 #include <kern/timer_call.h>
 #include <kern/task.h>
 #include <kern/exception.h>

+#include <kern/affinity.h>

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


@@ -123,9 +128,9 @@
 struct thread {
        /*
         *      NOTE:   The runq field in the thread structure has an unusual
 struct thread {
        /*
         *      NOTE:   The runq field in the thread structure has an unusual

-        *      locking protocol.  If its value is RUN_QUEUE_NULL, then it is
+        *      locking protocol.  If its value is PROCESSOR_NULL, then it is

         *      locked by the thread_lock, but if its value is something else
         *      locked by the thread_lock, but if its value is something else

-        *      (i.e. a run_queue) then it is locked by that run_queue's lock.
+        *      then it is locked by the associated run queue lock.

         *
         *      When the thread is on a wait queue, these first three fields
         *      are treated as an unofficial union with a wait_queue_element.
         *
         *      When the thread is on a wait queue, these first three fields
         *      are treated as an unofficial union with a wait_queue_element.


@@ -134,19 +139,18 @@ struct thread {
         */
        /* Items examined often, modified infrequently */
        queue_chain_t   links;                          /* run/wait queue links */
         */
        /* Items examined often, modified infrequently */
        queue_chain_t   links;                          /* run/wait queue links */

-       run_queue_t             runq;                           /* run queue thread is on SEE BELOW */
+       processor_t             runq;                           /* run queue assignment */

        wait_queue_t    wait_queue;                     /* wait queue we are currently on */
        event64_t               wait_event;                     /* wait queue event */
        integer_t               options;                        /* options set by thread itself */
 #define TH_OPT_INTMASK         0x03            /* interrupt / abort level */
 #define TH_OPT_VMPRIV          0x04            /* may allocate reserved memory */
        wait_queue_t    wait_queue;                     /* wait queue we are currently on */
        event64_t               wait_event;                     /* wait queue event */
        integer_t               options;                        /* options set by thread itself */
 #define TH_OPT_INTMASK         0x03            /* interrupt / abort level */
 #define TH_OPT_VMPRIV          0x04            /* may allocate reserved memory */

-#define TH_OPT_DELAYIDLE       0x08            /* performing delayed idle */
-#define TH_OPT_CALLOUT         0x10            /* executing as callout */
+#define TH_OPT_DTRACE          0x08            /* executing under dtrace_probe */

 
        /* Data updated during assert_wait/thread_wakeup */
        decl_simple_lock_data(,sched_lock)      /* scheduling lock (thread_lock()) */
 
        /* Data updated during assert_wait/thread_wakeup */
        decl_simple_lock_data(,sched_lock)      /* scheduling lock (thread_lock()) */

-       decl_simple_lock_data(,wake_lock)       /* covers wake_active (wake_lock())*/
-       boolean_t                       wake_active;    /* Someone is waiting for this */
+       decl_simple_lock_data(,wake_lock)       /* for thread stop / wait (wake_lock()) */
+       boolean_t                       wake_active;    /* wake event on stop */

        int                                     at_safe_point;  /* thread_abort_safely allowed */
        ast_t                           reason;                 /* why we blocked */
        wait_result_t           wait_result;    /* outcome of wait -
        int                                     at_safe_point;  /* thread_abort_safely allowed */
        ast_t                           reason;                 /* why we blocked */
        wait_result_t           wait_result;    /* outcome of wait -


@@ -175,12 +179,7 @@ struct thread {
 #define TH_UNINT               0x08                    /* waiting uninteruptibly */
 #define        TH_TERMINATE    0x10                    /* halted at termination */
 
 #define TH_UNINT               0x08                    /* waiting uninteruptibly */
 #define        TH_TERMINATE    0x10                    /* halted at termination */
 

-#define TH_ABORT               0x20                    /* abort interruptible waits */
-#define TH_ABORT_SAFELY        0x40                    /* ... but only those at safe point */
-
-#define TH_IDLE                        0x80                    /* processor idle thread */
-
-#define        TH_SCHED_STATE  (TH_WAIT|TH_SUSP|TH_RUN|TH_UNINT)
+#define TH_IDLE                        0x80                    /* idling processor */

 
        /* Scheduling information */
        integer_t                       sched_mode;                     /* scheduling mode bits */
 
        /* Scheduling information */
        integer_t                       sched_mode;                     /* scheduling mode bits */


@@ -189,8 +188,11 @@ struct thread {
 #define TH_MODE_PREEMPT                        0x0004          /* can preempt kernel contexts */
 #define TH_MODE_FAILSAFE               0x0008          /* fail-safe has tripped */
 #define        TH_MODE_PROMOTED                0x0010          /* sched pri has been promoted */
 #define TH_MODE_PREEMPT                        0x0004          /* can preempt kernel contexts */
 #define TH_MODE_FAILSAFE               0x0008          /* fail-safe has tripped */
 #define        TH_MODE_PROMOTED                0x0010          /* sched pri has been promoted */

-#define        TH_MODE_DEPRESS                 0x0020          /* normal depress yield */
-#define TH_MODE_POLLDEPRESS            0x0040          /* polled depress yield */
+#define TH_MODE_ABORT                  0x0020          /* abort interruptible waits */
+#define TH_MODE_ABORTSAFELY            0x0040          /* ... but only those at safe point */
+#define TH_MODE_ISABORTED              (TH_MODE_ABORT | TH_MODE_ABORTSAFELY)
+#define        TH_MODE_DEPRESS                 0x0080          /* normal depress yield */
+#define TH_MODE_POLLDEPRESS            0x0100          /* polled depress yield */

 #define TH_MODE_ISDEPRESSED            (TH_MODE_DEPRESS | TH_MODE_POLLDEPRESS)
 
        integer_t                       sched_pri;                      /* scheduled (current) priority */
 #define TH_MODE_ISDEPRESSED            (TH_MODE_DEPRESS | TH_MODE_POLLDEPRESS)
 
        integer_t                       sched_pri;                      /* scheduled (current) priority */


@@ -218,7 +220,6 @@ struct thread {
 
   /* Data used during setrun/dispatch */
        timer_data_t            system_timer;           /* system mode timer */
 
   /* Data used during setrun/dispatch */
        timer_data_t            system_timer;           /* system mode timer */

-       processor_set_t         processor_set;          /* assigned processor set */

        processor_t                     bound_processor;        /* bound to a processor? */
        processor_t                     last_processor;         /* processor last dispatched on */
        uint64_t                        last_switch;            /* time of last context switch */
        processor_t                     bound_processor;        /* bound to a processor? */
        processor_t                     last_processor;         /* processor last dispatched on */
        uint64_t                        last_switch;            /* time of last context switch */


@@ -229,17 +230,28 @@ struct thread {
        integer_t                       safe_mode;              /* saved mode during fail-safe */
        natural_t                       safe_release;   /* when to release fail-safe */
 
        integer_t                       safe_mode;              /* saved mode during fail-safe */
        natural_t                       safe_release;   /* when to release fail-safe */
 

+       /* Call out from scheduler */
+       void                            (*sched_call)(
+                                                       int                     type,
+                                                       thread_t        thread);
+

        /* Statistics and timesharing calculations */
        natural_t                       sched_stamp;    /* last scheduler tick */
        natural_t                       sched_usage;    /* timesharing cpu usage [sched] */
        natural_t                       pri_shift;              /* usage -> priority from pset */
        natural_t                       cpu_usage;              /* instrumented cpu usage [%cpu] */
        natural_t                       cpu_delta;              /* accumulated cpu_usage delta */
        /* Statistics and timesharing calculations */
        natural_t                       sched_stamp;    /* last scheduler tick */
        natural_t                       sched_usage;    /* timesharing cpu usage [sched] */
        natural_t                       pri_shift;              /* usage -> priority from pset */
        natural_t                       cpu_usage;              /* instrumented cpu usage [%cpu] */
        natural_t                       cpu_delta;              /* accumulated cpu_usage delta */

+       uint32_t                        c_switch;               /* total context switches */
+       uint32_t                        p_switch;               /* total processor switches */
+       uint32_t                        ps_switch;              /* total pset switches */

 
        /* Timing data structures */
        timer_data_t            user_timer;                     /* user mode timer */
 
        /* Timing data structures */
        timer_data_t            user_timer;                     /* user mode timer */

-       uint64_t                        system_timer_save;      /* saved system timer value */

        uint64_t                        user_timer_save;        /* saved user timer value */
        uint64_t                        user_timer_save;        /* saved user timer value */

+       uint64_t                        system_timer_save;      /* saved system timer value */
+       uint64_t                        vtimer_user_save;       /* saved values for vtimers */
+       uint64_t                        vtimer_prof_save;
+       uint64_t                        vtimer_rlim_save;

 
        /* Timed wait expiration */
        timer_call_data_t       wait_timer;
 
        /* Timed wait expiration */
        timer_call_data_t       wait_timer;


@@ -250,6 +262,13 @@ struct thread {
        timer_call_data_t       depress_timer;
        integer_t                       depress_timer_active;
 
        timer_call_data_t       depress_timer;
        integer_t                       depress_timer_active;
 

+       /*
+        * Processor/cache affinity
+        * - affinity_threads links task threads with the same affinity set
+        */
+       affinity_set_t                  affinity_set;
+       queue_chain_t                   affinity_threads;
+

        /* Various bits of stashed state */
        union {
                struct {
        /* Various bits of stashed state */
        union {
                struct {


@@ -282,14 +301,9 @@ struct thread {
 
        /* Ast/Halt data structures */
        vm_offset_t                     recover;                /* page fault recover(copyin/out) */
 
        /* Ast/Halt data structures */
        vm_offset_t                     recover;                /* page fault recover(copyin/out) */

-       int                                     ref_count;              /* number of references to me */
+       uint32_t                                        ref_count;              /* number of references to me */

 
 

-       /* Processor set info */
-       queue_chain_t           pset_threads;   /* list of all threads in pset */
-#if    MACH_HOST
-       boolean_t                       may_assign;             /* may assignment change? */
-       boolean_t                       assign_active;  /* waiting for may_assign */
-#endif /* MACH_HOST */
+       queue_chain_t           threads;                /* global list of all threads */

 
        /* Activation */
                queue_chain_t                   task_threads;
 
        /* Activation */
                queue_chain_t                   task_threads;


@@ -314,12 +328,10 @@ struct thread {
 
                /* Miscellaneous bits guarded by mutex */
                uint32_t
 
                /* Miscellaneous bits guarded by mutex */
                uint32_t

-               /* Indicates that the thread has not been terminated */
-                                               active:1,
-
-          /* Indicates that the thread has been started after creation */
-                                               started:1,
-                                               :0;
+                       active:1,                               /* Thread is active and has not been terminated */
+                       started:1,                              /* Thread has been started after creation */
+                       static_param:1,                 /* Disallow policy parameter changes */
+                       :0;

 
                /* Return Handers */
                struct ReturnHandler {
 
                /* Return Handers */
                struct ReturnHandler {


@@ -337,16 +349,16 @@ struct thread {
                /* Owned ulocks (a lock set element) */
                queue_head_t                    held_ulocks;
 
                /* Owned ulocks (a lock set element) */
                queue_head_t                    held_ulocks;
 

-#if    MACH_PROF
-               /* Profiling */
-               boolean_t                               profiled;
-               boolean_t                               profiled_own;
-               struct prof_data                *profil_buffer;
-#endif /* MACH_PROF */
-

 #ifdef MACH_BSD
                void                                    *uthread;
 #endif
 #ifdef MACH_BSD
                void                                    *uthread;
 #endif

+
+#if CONFIG_DTRACE
+               uint32_t t_dtrace_predcache;/* DTrace per thread predicate value hint */
+               int64_t t_dtrace_tracing;       /* Thread time under dtrace_probe() */
+               int64_t t_dtrace_vtime;
+#endif
+               uint32_t t_chud;        /* CHUD flags, used for Shark */

 };
 
 #define ith_state              saved.receive.state
 };
 
 #define ith_state              saved.receive.state


@@ -365,14 +377,14 @@ struct thread {
 #define sth_result             saved.sema.result
 #define sth_continuation       saved.sema.continuation
 
 #define sth_result             saved.sema.result
 #define sth_continuation       saved.sema.continuation
 

-extern void                    thread_bootstrap(void);
+extern void                    thread_bootstrap(void) __attribute__((section("__TEXT, initcode")));

 
 

-extern void                    thread_init(void);
+extern void                    thread_init(void) __attribute__((section("__TEXT, initcode")));

 
 extern void                    thread_daemon_init(void);
 
 #define        thread_reference_internal(thread)       \
 
 extern void                    thread_daemon_init(void);
 
 #define        thread_reference_internal(thread)       \

-                       hw_atomic_add(&(thread)->ref_count, 1)
+                       (void)hw_atomic_add(&(thread)->ref_count, 1)

 
 #define thread_deallocate_internal(thread)     \
                        hw_atomic_sub(&(thread)->ref_count, 1)
 
 #define thread_deallocate_internal(thread)     \
                        hw_atomic_sub(&(thread)->ref_count, 1)


@@ -380,7 +392,7 @@ extern void                 thread_daemon_init(void);
 #define thread_reference(thread)                                       \
 MACRO_BEGIN                                                                                    \
        if ((thread) != THREAD_NULL)                                    \
 #define thread_reference(thread)                                       \
 MACRO_BEGIN                                                                                    \
        if ((thread) != THREAD_NULL)                                    \

-               thread_reference_internal(thread);                      \
+               thread_reference_internal(thread);              \

 MACRO_END
 
 extern void                    thread_deallocate(
 MACRO_END
 
 extern void                    thread_deallocate(


@@ -391,6 +403,9 @@ extern void                 thread_terminate_self(void);
 extern kern_return_t   thread_terminate_internal(
                                                        thread_t                thread);
 
 extern kern_return_t   thread_terminate_internal(
                                                        thread_t                thread);
 

+extern void                    thread_start_internal(
+                                                       thread_t                        thread) __attribute__ ((noinline));
+

 extern void                    thread_terminate_enqueue(
                                                thread_t                thread);
 
 extern void                    thread_terminate_enqueue(
                                                thread_t                thread);
 


@@ -406,14 +421,12 @@ extern void                       thread_release(
 #define        thread_lock_init(th)    simple_lock_init(&(th)->sched_lock, 0)
 #define thread_lock(th)                        simple_lock(&(th)->sched_lock)
 #define thread_unlock(th)              simple_unlock(&(th)->sched_lock)
 #define        thread_lock_init(th)    simple_lock_init(&(th)->sched_lock, 0)
 #define thread_lock(th)                        simple_lock(&(th)->sched_lock)
 #define thread_unlock(th)              simple_unlock(&(th)->sched_lock)

-#define thread_lock_try(th)            simple_lock_try(&(th)->sched_lock)
-
-#define thread_should_halt_fast(thread)                (!(thread)->active)

 
 #define wake_lock_init(th)             simple_lock_init(&(th)->wake_lock, 0)
 #define wake_lock(th)                  simple_lock(&(th)->wake_lock)
 #define wake_unlock(th)                        simple_unlock(&(th)->wake_lock)
 
 #define wake_lock_init(th)             simple_lock_init(&(th)->wake_lock, 0)
 #define wake_lock(th)                  simple_lock(&(th)->wake_lock)
 #define wake_unlock(th)                        simple_unlock(&(th)->wake_lock)

-#define wake_lock_try(th)              simple_lock_try(&(th)->wake_lock)
+
+#define thread_should_halt_fast(thread)                (!(thread)->active)

 
 extern void                            stack_alloc(
                                                        thread_t                thread);
 
 extern void                            stack_alloc(
                                                        thread_t                thread);


@@ -429,7 +442,7 @@ extern boolean_t            stack_alloc_try(
 
 extern void                            stack_collect(void);
 
 
 extern void                            stack_collect(void);
 

-extern void                            stack_init(void);
+extern void                            stack_init(void) __attribute__((section("__TEXT, initcode")));

 
 extern kern_return_t    thread_state_initialize(
                                                        thread_t                                thread);
 
 extern kern_return_t    thread_state_initialize(
                                                        thread_t                                thread);


@@ -516,8 +529,7 @@ extern kern_return_t        machine_thread_create(
                                                        thread_t                thread,
                                                        task_t                  task);
 extern void            machine_thread_switch_addrmode(
                                                        thread_t                thread,
                                                        task_t                  task);
 extern void            machine_thread_switch_addrmode(

-                                                      thread_t                 thread,
-                                                      int                      oldmode_is64bit);
+                                                      thread_t                 thread);

 
 extern void                machine_thread_destroy(
                                                        thread_t                thread);
 
 extern void                machine_thread_destroy(
                                                        thread_t                thread);


@@ -561,6 +573,8 @@ extern void                 special_handler(
                                                ReturnHandler   *rh,
                                                thread_t                thread);
 
                                                ReturnHandler   *rh,
                                                thread_t                thread);
 

+void act_machine_sv_free(thread_t, int);
+

 #else  /* MACH_KERNEL_PRIVATE */
 
 __BEGIN_DECLS
 #else  /* MACH_KERNEL_PRIVATE */
 
 __BEGIN_DECLS


@@ -614,6 +628,9 @@ __BEGIN_DECLS
 
 #ifdef XNU_KERNEL_PRIVATE
 
 
 #ifdef XNU_KERNEL_PRIVATE
 

+extern void    thread_yield_internal(
+       mach_msg_timeout_t      interval);
+

 /*
  * XXX Funnel locks XXX
  */
 /*
  * XXX Funnel locks XXX
  */


@@ -643,7 +660,7 @@ extern void                 thread_setentrypoint(
                                                thread_t                thread,
                                                mach_vm_offset_t        entry);
 
                                                thread_t                thread,
                                                mach_vm_offset_t        entry);
 

-extern void            thread_setsinglestep(
+extern kern_return_t   thread_setsinglestep(

                                                thread_t                thread,
                                                int                     on);
 
                                                thread_t                thread,
                                                int                     on);
 


@@ -653,12 +670,23 @@ extern kern_return_t      thread_wire_internal(
                                                        boolean_t               wired,
                                                        boolean_t               *prev_state);
 
                                                        boolean_t               wired,
                                                        boolean_t               *prev_state);
 

-/* JMM - These are only temporary */
-extern boolean_t       is_thread_running(thread_t); /* True is TH_RUN */
-extern boolean_t       is_thread_idle(thread_t); /* True is TH_IDLE */
-

 extern kern_return_t   thread_dup(thread_t);
 
 extern kern_return_t   thread_dup(thread_t);
 

+typedef void   (*sched_call_t)(
+                                       int                             type,
+                                       thread_t                thread);
+
+#define SCHED_CALL_BLOCK               0x1
+#define SCHED_CALL_UNBLOCK             0x2
+
+extern void            thread_sched_call(
+                                       thread_t                thread,
+                                       sched_call_t    call);
+
+extern void            thread_static_param(
+                                       thread_t                thread,
+                                       boolean_t               state);
+

 extern task_t  get_threadtask(thread_t);
 #define thread_is_64bit(thd)   \
        task_has_64BitAddr(get_threadtask(thd))
 extern task_t  get_threadtask(thread_t);
 #define thread_is_64bit(thd)   \
        task_has_64BitAddr(get_threadtask(thd))


@@ -667,11 +695,39 @@ extern task_t     get_threadtask(thread_t);
 extern void            *get_bsdthread_info(thread_t);
 extern void            set_bsdthread_info(thread_t, void *);
 extern void            *uthread_alloc(task_t, thread_t);
 extern void            *get_bsdthread_info(thread_t);
 extern void            set_bsdthread_info(thread_t, void *);
 extern void            *uthread_alloc(task_t, thread_t);

-extern void            uthread_free(task_t, void *, void *); 
+extern void            uthread_cleanup(task_t, void *, void *); 
+extern void            uthread_zone_free(void *); 
+extern void            uthread_cred_free(void *); 

 
 extern boolean_t       thread_should_halt(
                                                thread_t                thread);
 
 
 extern boolean_t       thread_should_halt(
                                                thread_t                thread);
 

+extern int is_64signalregset(void);
+
+void act_set_apc(thread_t);
+
+extern uint32_t dtrace_get_thread_predcache(thread_t);
+extern int64_t dtrace_get_thread_vtime(thread_t);
+extern int64_t dtrace_get_thread_tracing(thread_t);
+extern boolean_t dtrace_get_thread_reentering(thread_t);
+extern vm_offset_t dtrace_get_kernel_stack(thread_t);
+extern void dtrace_set_thread_predcache(thread_t, uint32_t);
+extern void dtrace_set_thread_vtime(thread_t, int64_t);
+extern void dtrace_set_thread_tracing(thread_t, int64_t);
+extern void dtrace_set_thread_reentering(thread_t, boolean_t);
+extern vm_offset_t dtrace_set_thread_recover(thread_t, vm_offset_t);
+
+extern int64_t dtrace_calc_thread_recent_vtime(thread_t);
+
+
+extern void            thread_set_wq_state32(
+                                             thread_t          thread,
+                                             thread_state_t    tstate);
+
+extern void            thread_set_wq_state64(
+                                             thread_t          thread,
+                                             thread_state_t    tstate);
+

 #endif /* XNU_KERNEL_PRIVATE */
 
 extern kern_return_t   kernel_thread_start(
 #endif /* XNU_KERNEL_PRIVATE */
 
 extern kern_return_t   kernel_thread_start(