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 [email protected]
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
timer_init(timer_t timer)74 timer_init(timer_t timer)
75 {
76 memset(timer, 0, sizeof(*timer));
77 }
78
79 uint64_t
timer_delta(timer_t timer,uint64_t * prev_in_cur_out)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
timer_advance(timer_t timer,uint64_t delta)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
timer_start(timer_t timer,uint64_t tstamp)106 timer_start(timer_t timer, uint64_t tstamp)
107 {
108 timer->tstamp = tstamp;
109 }
110
111 void
timer_stop(timer_t timer,uint64_t tstamp)112 timer_stop(timer_t timer, uint64_t tstamp)
113 {
114 timer_advance(timer, tstamp - timer->tstamp);
115 }
116
117 void
timer_update(timer_t timer,uint64_t tstamp)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
timer_switch(timer_t timer,uint64_t tstamp,timer_t new_timer)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
processor_timer_switch_thread(uint64_t tstamp,timer_t new_timer)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 }
151