xref: /kernel/linux/linux-5.10/arch/um/os-Linux/time.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
4 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
5 * Copyright (C) 2012-2014 Cisco Systems
6 * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
7 */
8
9#include <stddef.h>
10#include <errno.h>
11#include <signal.h>
12#include <time.h>
13#include <sys/time.h>
14#include <kern_util.h>
15#include <os.h>
16#include <string.h>
17
18static timer_t event_high_res_timer = 0;
19
20static inline long long timeval_to_ns(const struct timeval *tv)
21{
22	return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
23		tv->tv_usec * UM_NSEC_PER_USEC;
24}
25
26static inline long long timespec_to_ns(const struct timespec *ts)
27{
28	return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) + ts->tv_nsec;
29}
30
31long long os_persistent_clock_emulation(void)
32{
33	struct timespec realtime_tp;
34
35	clock_gettime(CLOCK_REALTIME, &realtime_tp);
36	return timespec_to_ns(&realtime_tp);
37}
38
39/**
40 * os_timer_create() - create an new posix (interval) timer
41 */
42int os_timer_create(void)
43{
44	timer_t *t = &event_high_res_timer;
45
46	if (timer_create(CLOCK_MONOTONIC, NULL, t) == -1)
47		return -1;
48
49	return 0;
50}
51
52int os_timer_set_interval(unsigned long long nsecs)
53{
54	struct itimerspec its;
55
56	its.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC;
57	its.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC;
58
59	its.it_interval.tv_sec = nsecs / UM_NSEC_PER_SEC;
60	its.it_interval.tv_nsec = nsecs % UM_NSEC_PER_SEC;
61
62	if (timer_settime(event_high_res_timer, 0, &its, NULL) == -1)
63		return -errno;
64
65	return 0;
66}
67
68int os_timer_one_shot(unsigned long long nsecs)
69{
70	struct itimerspec its = {
71		.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC,
72		.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC,
73
74		.it_interval.tv_sec = 0,
75		.it_interval.tv_nsec = 0, // we cheat here
76	};
77
78	timer_settime(event_high_res_timer, 0, &its, NULL);
79	return 0;
80}
81
82/**
83 * os_timer_disable() - disable the posix (interval) timer
84 */
85void os_timer_disable(void)
86{
87	struct itimerspec its;
88
89	memset(&its, 0, sizeof(struct itimerspec));
90	timer_settime(event_high_res_timer, 0, &its, NULL);
91}
92
93long long os_nsecs(void)
94{
95	struct timespec ts;
96
97	clock_gettime(CLOCK_MONOTONIC,&ts);
98	return timespec_to_ns(&ts);
99}
100
101/**
102 * os_idle_sleep() - sleep for a given time of nsecs
103 * @nsecs: nanoseconds to sleep
104 */
105void os_idle_sleep(unsigned long long nsecs)
106{
107	struct timespec ts = {
108		.tv_sec  = nsecs / UM_NSEC_PER_SEC,
109		.tv_nsec = nsecs % UM_NSEC_PER_SEC
110	};
111
112	/*
113	 * Relay the signal if clock_nanosleep is interrupted.
114	 */
115	if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL))
116		deliver_alarm();
117}
118