osfmk/kern/timer.c

   1 /*
   2  * Copyright (c) 2000-2018 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 #include <mach/kern_return.h>
  58 #include <mach/port.h>
  59 #include <kern/queue.h>
  60 #include <kern/processor.h>
  61 #include <kern/thread.h>
  62 #include <kern/sched_prim.h>
  63 #include <kern/timer.h>
  64
  65 #if CONFIG_EMBEDDED
  66 int precise_user_kernel_time = 0;
  67 #else
  68 int precise_user_kernel_time = 1;
  69 #endif
  70
  71 void
  72 timer_init(timer_t timer)
  73 {
  74         memset(timer, 0, sizeof(*timer));
  75 }
  76
  77 uint64_t
  78 timer_delta(timer_t timer, uint64_t *prev_in_cur_out)
  79 {
  80         uint64_t old = *prev_in_cur_out;
  81         uint64_t new = *prev_in_cur_out = timer_grab(timer);
  82         return new - old;
  83 }
  84
  85 static void
  86 timer_advance(timer_t timer, uint64_t delta)
  87 {
  88 #if defined(__LP64__)
  89         timer->all_bits += delta;
  90 #else /* defined(__LP64__) */
  91         extern void timer_advance_internal_32(timer_t timer, uint32_t high,
  92             uint32_t low);
  93         uint64_t low = delta + timer->low_bits;
  94         if (low >> 32) {
  95                 timer_advance_internal_32(timer,
  96                     (uint32_t)(timer->high_bits + (low >> 32)), (uint32_t)low);
  97         } else {
  98                 timer->low_bits = (uint32_t)low;
  99         }
 100 #endif /* defined(__LP64__) */
 101 }
 102
 103 void
 104 timer_start(timer_t timer, uint64_t tstamp)
 105 {
 106         timer->tstamp = tstamp;
 107 }
 108
 109 void
 110 timer_stop(timer_t timer, uint64_t tstamp)
 111 {
 112         timer_advance(timer, tstamp - timer->tstamp);
 113 }
 114
 115 void
 116 timer_update(timer_t timer, uint64_t tstamp)
 117 {
 118         timer_advance(timer, tstamp - timer->tstamp);
 119         timer->tstamp = tstamp;
 120 }
 121
 122 void
 123 timer_switch(timer_t timer, uint64_t tstamp, timer_t new_timer)
 124 {
 125         timer_advance(timer, tstamp - timer->tstamp);
 126         new_timer->tstamp = tstamp;
 127 }
 128
 129 /*
 130  * Update the current processor's thread timer with `tstamp` and switch the
 131  * processor's thread timer to `new_timer`.
 132  *
 133  * Called with interrupts disabled.
 134  */
 135 void
 136 processor_timer_switch_thread(uint64_t tstamp, timer_t new_timer)
 137 {
 138         processor_t processor = current_processor();
 139         timer_t timer;
 140
 141         /* Update current timer. */
 142         timer = PROCESSOR_DATA(processor, thread_timer);
 143         timer_advance(timer, tstamp - timer->tstamp);
 144
 145         /* Start new timer. */
 146         PROCESSOR_DATA(processor, thread_timer) = new_timer;
 147         new_timer->tstamp = tstamp;
 148 }