osfmk/kern/timer.c

   1 /*
   2  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58
  59 #include <mach/kern_return.h>
  60 #include <mach/port.h>
  61 #include <kern/queue.h>
  62 #include <kern/processor.h>
  63 #include <kern/thread.h>
  64 #include <kern/sched_prim.h>
  65 #include <kern/timer.h>
  66
  67 int precise_user_kernel_time = 1;
  68
  69 /*
  70  *      timer_init initializes a timer.
  71  */
  72 void
  73 timer_init(
  74         timer_t         timer)
  75 {
  76         timer->tstamp = 0;
  77 #if     defined(__LP64__)
  78         timer->all_bits = 0;
  79 #else
  80         timer->low_bits = 0;
  81         timer->high_bits = 0;
  82         timer->high_bits_check = 0;
  83 #endif  /* defined(__LP64__) */
  84 }
  85
  86 /*
  87  *      Calculate the difference between a timer
  88  *      and saved value, and update the saved value.
  89  */
  90 uint64_t
  91 timer_delta(
  92         timer_t         timer,
  93         uint64_t        *save)
  94 {
  95         uint64_t        new, old = *save;
  96
  97         *save = new = timer_grab(timer);
  98
  99         return (new - old);
 100 }
 101
 102 void
 103 timer_advance(
 104         timer_t         timer,
 105         uint64_t        delta)
 106 {
 107 #if     defined(__LP64__)
 108         timer->all_bits += delta;
 109 #else
 110         uint64_t        low;
 111
 112         low = delta + timer->low_bits;
 113         if (low >> 32)
 114                 timer_update(timer, (uint32_t)(timer->high_bits + (low >> 32)), (uint32_t)low);
 115         else
 116                 timer->low_bits = (uint32_t)low;
 117 #endif  /* defined(__LP64__) */
 118 }
 119
 120 void
 121 timer_start(
 122         timer_t         timer,
 123         uint64_t        tstamp)
 124 {
 125         timer->tstamp = tstamp;
 126 }
 127
 128 void
 129 timer_stop(
 130         timer_t         timer,
 131         uint64_t        tstamp)
 132 {
 133         timer_advance(timer, tstamp - timer->tstamp);
 134 }
 135
 136 /*
 137  *      Update the timer and start a new one.
 138  */
 139 void
 140 timer_switch(
 141         timer_t                 timer,
 142         uint64_t                tstamp,
 143         timer_t                 new_timer)
 144 {
 145         timer_advance(timer, tstamp - timer->tstamp);
 146         new_timer->tstamp = tstamp;
 147 }
 148
 149 /*
 150  *      Update the current thread timer and
 151  *      start the new timer.  Requires a current
 152  *      and new timer.
 153  *
 154  *      Called with interrupts disabled.
 155  */
 156 void
 157 thread_timer_event(
 158         uint64_t                tstamp,
 159         timer_t                 new_timer)
 160 {
 161         processor_t             processor = current_processor();
 162         timer_t                 timer;
 163
 164         /*
 165          *      Update current timer.
 166          */
 167         timer = PROCESSOR_DATA(processor, thread_timer);
 168         timer_advance(timer, tstamp - timer->tstamp);
 169
 170         /*
 171          *      Start new timer.
 172          */
 173         PROCESSOR_DATA(processor, thread_timer) = new_timer;
 174         new_timer->tstamp = tstamp;
 175 }