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