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1/*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <stddef.h>
7#include <errno.h>
8#include <signal.h>
9#include <time.h>
10#include <sys/time.h>
11#include "kern_util.h"
12#include "os.h"
13#include "internal.h"
14
15int set_interval(void)
16{
17 int usec = UM_USEC_PER_SEC / UM_HZ;
18 struct itimerval interval = ((struct itimerval) { { 0, usec },
19 { 0, usec } });
20
21 if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
22 return -errno;
23
24 return 0;
25}
26
27int timer_one_shot(int ticks)
28{
29 unsigned long usec = ticks * UM_USEC_PER_SEC / UM_HZ;
30 unsigned long sec = usec / UM_USEC_PER_SEC;
31 struct itimerval interval;
32
33 usec %= UM_USEC_PER_SEC;
34 interval = ((struct itimerval) { { 0, 0 }, { sec, usec } });
35
36 if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
37 return -errno;
38
39 return 0;
40}
41
42/**
43 * timeval_to_ns - Convert timeval to nanoseconds
44 * @ts: pointer to the timeval variable to be converted
45 *
46 * Returns the scalar nanosecond representation of the timeval
47 * parameter.
48 *
49 * Ripped from linux/time.h because it's a kernel header, and thus
50 * unusable from here.
51 */
52static inline long long timeval_to_ns(const struct timeval *tv)
53{
54 return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
55 tv->tv_usec * UM_NSEC_PER_USEC;
56}
57
58long long disable_timer(void)
59{
60 struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
61 long long remain, max = UM_NSEC_PER_SEC / UM_HZ;
62
63 if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
64 printk(UM_KERN_ERR "disable_timer - setitimer failed, "
65 "errno = %d\n", errno);
66
67 remain = timeval_to_ns(&time.it_value);
68 if (remain > max)
69 remain = max;
70
71 return remain;
72}
73
74long long os_nsecs(void)
75{
76 struct timeval tv;
77
78 gettimeofday(&tv, NULL);
79 return timeval_to_ns(&tv);
80}
81
82#ifdef UML_CONFIG_NO_HZ
83static int after_sleep_interval(struct timespec *ts)
84{
85 return 0;
86}
87
88static void deliver_alarm(void)
89{
90 alarm_handler(SIGVTALRM, NULL);
91}
92
93static unsigned long long sleep_time(unsigned long long nsecs)
94{
95 return nsecs;
96}
97
98#else
99unsigned long long last_tick;
100unsigned long long skew;
101
102static void deliver_alarm(void)
103{
104 unsigned long long this_tick = os_nsecs();
105 int one_tick = UM_NSEC_PER_SEC / UM_HZ;
106
107 /* Protection against the host's time going backwards */
108 if ((last_tick != 0) && (this_tick < last_tick))
109 this_tick = last_tick;
110
111 if (last_tick == 0)
112 last_tick = this_tick - one_tick;
113
114 skew += this_tick - last_tick;
115
116 while (skew >= one_tick) {
117 alarm_handler(SIGVTALRM, NULL);
118 skew -= one_tick;
119 }
120
121 last_tick = this_tick;
122}
123
124static unsigned long long sleep_time(unsigned long long nsecs)
125{
126 return nsecs > skew ? nsecs - skew : 0;
127}
128
129static inline long long timespec_to_us(const struct timespec *ts)
130{
131 return ((long long) ts->tv_sec * UM_USEC_PER_SEC) +
132 ts->tv_nsec / UM_NSEC_PER_USEC;
133}
134
135static int after_sleep_interval(struct timespec *ts)
136{
137 int usec = UM_USEC_PER_SEC / UM_HZ;
138 long long start_usecs = timespec_to_us(ts);
139 struct timeval tv;
140 struct itimerval interval;
141
142 /*
143 * It seems that rounding can increase the value returned from
144 * setitimer to larger than the one passed in. Over time,
145 * this will cause the remaining time to be greater than the
146 * tick interval. If this happens, then just reduce the first
147 * tick to the interval value.
148 */
149 if (start_usecs > usec)
150 start_usecs = usec;
151
152 start_usecs -= skew / UM_NSEC_PER_USEC;
153 if (start_usecs < 0)
154 start_usecs = 0;
155
156 tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC,
157 .tv_usec = start_usecs % UM_USEC_PER_SEC });
158 interval = ((struct itimerval) { { 0, usec }, tv });
159
160 if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
161 return -errno;
162
163 return 0;
164}
165#endif
166
167void idle_sleep(unsigned long long nsecs)
168{
169 struct timespec ts;
170
171 /*
172 * nsecs can come in as zero, in which case, this starts a
173 * busy loop. To prevent this, reset nsecs to the tick
174 * interval if it is zero.
175 */
176 if (nsecs == 0)
177 nsecs = UM_NSEC_PER_SEC / UM_HZ;
178
179 nsecs = sleep_time(nsecs);
180 ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC,
181 .tv_nsec = nsecs % UM_NSEC_PER_SEC });
182
183 if (nanosleep(&ts, &ts) == 0)
184 deliver_alarm();
185 after_sleep_interval(&ts);
186}
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#include <timer-internal.h>
18
19static timer_t event_high_res_timer = 0;
20
21static inline long long timeval_to_ns(const struct timeval *tv)
22{
23 return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
24 tv->tv_usec * UM_NSEC_PER_USEC;
25}
26
27static inline long long timespec_to_ns(const struct timespec *ts)
28{
29 return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) + ts->tv_nsec;
30}
31
32long long os_persistent_clock_emulation(void)
33{
34 struct timespec realtime_tp;
35
36 clock_gettime(CLOCK_REALTIME, &realtime_tp);
37 return timespec_to_ns(&realtime_tp);
38}
39
40/**
41 * os_timer_create() - create an new posix (interval) timer
42 */
43int os_timer_create(void)
44{
45 timer_t *t = &event_high_res_timer;
46
47 if (timer_create(CLOCK_MONOTONIC, NULL, t) == -1)
48 return -1;
49
50 return 0;
51}
52
53int os_timer_set_interval(unsigned long long nsecs)
54{
55 struct itimerspec its;
56
57 its.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC;
58 its.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC;
59
60 its.it_interval.tv_sec = nsecs / UM_NSEC_PER_SEC;
61 its.it_interval.tv_nsec = nsecs % UM_NSEC_PER_SEC;
62
63 if (timer_settime(event_high_res_timer, 0, &its, NULL) == -1)
64 return -errno;
65
66 return 0;
67}
68
69int os_timer_one_shot(unsigned long long nsecs)
70{
71 struct itimerspec its = {
72 .it_value.tv_sec = nsecs / UM_NSEC_PER_SEC,
73 .it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC,
74
75 .it_interval.tv_sec = 0,
76 .it_interval.tv_nsec = 0, // we cheat here
77 };
78
79 timer_settime(event_high_res_timer, 0, &its, NULL);
80 return 0;
81}
82
83/**
84 * os_timer_disable() - disable the posix (interval) timer
85 */
86void os_timer_disable(void)
87{
88 struct itimerspec its;
89
90 memset(&its, 0, sizeof(struct itimerspec));
91 timer_settime(event_high_res_timer, 0, &its, NULL);
92}
93
94long long os_nsecs(void)
95{
96 struct timespec ts;
97
98 clock_gettime(CLOCK_MONOTONIC,&ts);
99 return timespec_to_ns(&ts);
100}
101
102/**
103 * os_idle_sleep() - sleep for a given time of nsecs
104 * @nsecs: nanoseconds to sleep
105 */
106void os_idle_sleep(unsigned long long nsecs)
107{
108 struct timespec ts = {
109 .tv_sec = nsecs / UM_NSEC_PER_SEC,
110 .tv_nsec = nsecs % UM_NSEC_PER_SEC
111 };
112
113 /*
114 * Relay the signal if clock_nanosleep is interrupted.
115 */
116 if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL))
117 deliver_alarm();
118}