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 #include <machine/config.h>
  66
  67 #if CONFIG_SKIP_PRECISE_USER_KERNEL_TIME && !HAS_FAST_CNTVCT
  68 int precise_user_kernel_time = 0;
  69 #else
  70 int precise_user_kernel_time = 1;
  71 #endif
  72
  73 void
  74 timer_init(timer_t timer)
  75 {
  76         memset(timer, 0, sizeof(*timer));
  77 }
  78
  79 uint64_t
  80 timer_delta(timer_t timer, uint64_t *prev_in_cur_out)
  81 {
  82         uint64_t old = *prev_in_cur_out;
  83         uint64_t new = *prev_in_cur_out = timer_grab(timer);
  84         return new - old;
  85 }
  86
  87 static void
  88 timer_advance(timer_t timer, uint64_t delta)
  89 {
  90 #if defined(__LP64__)
  91         timer->all_bits += delta;
  92 #else /* defined(__LP64__) */
  93         extern void timer_advance_internal_32(timer_t timer, uint32_t high,
  94             uint32_t low);
  95         uint64_t low = delta + timer->low_bits;
  96         if (low >> 32) {
  97                 timer_advance_internal_32(timer,
  98                     (uint32_t)(timer->high_bits + (low >> 32)), (uint32_t)low);
  99         } else {
 100                 timer->low_bits = (uint32_t)low;
 101         }
 102 #endif /* defined(__LP64__) */
 103 }
 104
 105 void
 106 timer_start(timer_t timer, uint64_t tstamp)
 107 {
 108         timer->tstamp = tstamp;
 109 }
 110
 111 void
 112 timer_stop(timer_t timer, uint64_t tstamp)
 113 {
 114         timer_advance(timer, tstamp - timer->tstamp);
 115 }
 116
 117 void
 118 timer_update(timer_t timer, uint64_t tstamp)
 119 {
 120         timer_advance(timer, tstamp - timer->tstamp);
 121         timer->tstamp = tstamp;
 122 }
 123
 124 void
 125 timer_switch(timer_t timer, uint64_t tstamp, timer_t new_timer)
 126 {
 127         timer_advance(timer, tstamp - timer->tstamp);
 128         new_timer->tstamp = tstamp;
 129 }
 130
 131 /*
 132  * Update the current processor's thread timer with `tstamp` and switch the
 133  * processor's thread timer to `new_timer`.
 134  *
 135  * Called with interrupts disabled.
 136  */
 137 void
 138 processor_timer_switch_thread(uint64_t tstamp, timer_t new_timer)
 139 {
 140         processor_t processor = current_processor();
 141         timer_t timer;
 142
 143         /* Update current timer. */
 144         timer = processor->thread_timer;
 145         timer_advance(timer, tstamp - timer->tstamp);
 146
 147         /* Start new timer. */
 148         processor->thread_timer = new_timer;
 149         new_timer->tstamp = tstamp;
 150 }