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 <machine_timer_routines.h>
  60
  61 #include <mach/kern_return.h>
  62 #include <mach/port.h>
  63 #include <kern/queue.h>
  64 #include <kern/processor.h>
  65 #include <kern/thread.h>
  66 #include <kern/sched_prim.h>
  67 #include <kern/timer.h>
  68
  69 #if CONFIG_EMBEDDED
  70 int precise_user_kernel_time = 0;
  71 #else
  72 int precise_user_kernel_time = 1;
  73 #endif
  74
  75 /*
  76  *      timer_init initializes a timer.
  77  */
  78 void
  79 timer_init(
  80         timer_t         timer)
  81 {
  82         timer->tstamp = 0;
  83 #if     defined(__LP64__)
  84         timer->all_bits = 0;
  85 #else
  86         timer->low_bits = 0;
  87         timer->high_bits = 0;
  88         timer->high_bits_check = 0;
  89 #endif  /* defined(__LP64__) */
  90 }
  91
  92 /*
  93  *      Calculate the difference between a timer
  94  *      and saved value, and update the saved value.
  95  */
  96 uint64_t
  97 timer_delta(
  98         timer_t         timer,
  99         uint64_t        *save)
 100 {
 101         uint64_t        new, old = *save;
 102
 103         *save = new = timer_grab(timer);
 104
 105         return (new - old);
 106 }
 107
 108 void
 109 timer_advance(
 110         timer_t         timer,
 111         uint64_t        delta)
 112 {
 113 #if     defined(__LP64__)
 114         timer->all_bits += delta;
 115 #else
 116         uint64_t        low;
 117
 118         low = delta + timer->low_bits;
 119         if (low >> 32)
 120                 timer_update(timer, (uint32_t)(timer->high_bits + (low >> 32)), (uint32_t)low);
 121         else
 122                 timer->low_bits = (uint32_t)low;
 123 #endif  /* defined(__LP64__) */
 124 }
 125
 126 void
 127 timer_start(
 128         timer_t         timer,
 129         uint64_t        tstamp)
 130 {
 131         timer->tstamp = tstamp;
 132 }
 133
 134 void
 135 timer_stop(
 136         timer_t         timer,
 137         uint64_t        tstamp)
 138 {
 139         timer_advance(timer, tstamp - timer->tstamp);
 140 }
 141
 142 /*
 143  *      Update the timer and start a new one.
 144  */
 145 void
 146 timer_switch(
 147         timer_t                 timer,
 148         uint64_t                tstamp,
 149         timer_t                 new_timer)
 150 {
 151         timer_advance(timer, tstamp - timer->tstamp);
 152         new_timer->tstamp = tstamp;
 153 }
 154
 155 #if     MACHINE_TIMER_ROUTINES
 156
 157 /*
 158  *      Machine-dependent code implements the timer event routine.
 159  */
 160
 161 #else   /* MACHINE_TIMER_ROUTINES */
 162
 163 /*
 164  *      Update the current thread timer and
 165  *      start the new timer.  Requires a current
 166  *      and new timer.
 167  *
 168  *      Called with interrupts disabled.
 169  */
 170 void
 171 thread_timer_event(
 172         uint64_t                tstamp,
 173         timer_t                 new_timer)
 174 {
 175         processor_t             processor = current_processor();
 176         timer_t                 timer;
 177
 178         /*
 179          *      Update current timer.
 180          */
 181         timer = PROCESSOR_DATA(processor, thread_timer);
 182         timer_advance(timer, tstamp - timer->tstamp);
 183
 184         /*
 185          *      Start new timer.
 186          */
 187         PROCESSOR_DATA(processor, thread_timer) = new_timer;
 188         new_timer->tstamp = tstamp;
 189 }
 190
 191 #endif  /* MACHINE_TIMER_ROUTINES */