blob: 910499d76a678a1830f5ea634c86acfd67276493 [file] [log] [blame]
Gennady Sharapovcff65c42006-01-18 17:42:42 -08001/*
Jeff Dike4c9e1382007-10-16 01:26:54 -07002 * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
Gennady Sharapovcff65c42006-01-18 17:42:42 -08003 * Licensed under the GPL
4 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07005
Jeff Dike4c9e1382007-10-16 01:26:54 -07006#include <stddef.h>
7#include <errno.h>
8#include <signal.h>
Gennady Sharapovcff65c42006-01-18 17:42:42 -08009#include <time.h>
10#include <sys/time.h>
Jeff Dikefe2cc532008-05-12 14:02:00 -070011#include "kern_util.h"
Gennady Sharapovcff65c42006-01-18 17:42:42 -080012#include "os.h"
Al Viro248b74c2011-08-18 20:05:09 +010013#include "internal.h"
Gennady Sharapovcff65c42006-01-18 17:42:42 -080014
Jeff Dikea2f018b2007-10-16 01:27:22 -070015int set_interval(void)
Gennady Sharapovcff65c42006-01-18 17:42:42 -080016{
Jeff Dike1a805212007-10-16 01:27:28 -070017 int usec = UM_USEC_PER_SEC / UM_HZ;
Gennady Sharapovcff65c42006-01-18 17:42:42 -080018 struct itimerval interval = ((struct itimerval) { { 0, usec },
19 { 0, usec } });
20
Jeff Dikea2f018b2007-10-16 01:27:22 -070021 if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
Jeff Dike537ae942006-09-25 23:33:05 -070022 return -errno;
23
24 return 0;
Gennady Sharapovcff65c42006-01-18 17:42:42 -080025}
26
Jeff Diked2753a6d2007-10-16 01:27:25 -070027int timer_one_shot(int ticks)
28{
Jeff Dike1a805212007-10-16 01:27:28 -070029 unsigned long usec = ticks * UM_USEC_PER_SEC / UM_HZ;
30 unsigned long sec = usec / UM_USEC_PER_SEC;
Jeff Diked2753a6d2007-10-16 01:27:25 -070031 struct itimerval interval;
32
Jeff Dike1a805212007-10-16 01:27:28 -070033 usec %= UM_USEC_PER_SEC;
Jeff Diked2753a6d2007-10-16 01:27:25 -070034 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
Jeff Dike5f734612007-10-16 01:27:27 -070042/**
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)
Gennady Sharapovcff65c42006-01-18 17:42:42 -080059{
Jeff Dikeb160fb62007-10-16 01:27:26 -070060 struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
Richard Weinberger482db6d2010-10-26 14:21:13 -070061 long long remain, max = UM_NSEC_PER_SEC / UM_HZ;
Jeff Dike4c9e1382007-10-16 01:26:54 -070062
Jeff Dike364e3a32007-11-28 16:21:51 -080063 if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
Jeff Dike4c9e1382007-10-16 01:26:54 -070064 printk(UM_KERN_ERR "disable_timer - setitimer failed, "
65 "errno = %d\n", errno);
Gennady Sharapovcff65c42006-01-18 17:42:42 -080066
Jeff Dikefe2cc532008-05-12 14:02:00 -070067 remain = timeval_to_ns(&time.it_value);
68 if (remain > max)
69 remain = max;
70
71 return remain;
Gennady Sharapovcff65c42006-01-18 17:42:42 -080072}
73
Jeff Dike5f734612007-10-16 01:27:27 -070074long long os_nsecs(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070075{
76 struct timeval tv;
77
78 gettimeofday(&tv, NULL);
Jeff Diked2753a6d2007-10-16 01:27:25 -070079 return timeval_to_ns(&tv);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080}
81
Jeff Dike364e3a32007-11-28 16:21:51 -080082#ifdef UML_CONFIG_NO_HZ
83static int after_sleep_interval(struct timespec *ts)
84{
Jeff Dike0a765322007-12-01 12:16:29 -080085 return 0;
Jeff Dike364e3a32007-11-28 16:21:51 -080086}
Jeff Dikefe2cc532008-05-12 14:02:00 -070087
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
Jeff Dike364e3a32007-11-28 16:21:51 -080098#else
Jeff Dikefe2cc532008-05-12 14:02:00 -070099unsigned 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
Jeff Dike06e1e4f2008-06-05 22:46:10 -0700107 /* Protection against the host's time going backwards */
108 if ((last_tick != 0) && (this_tick < last_tick))
109 this_tick = last_tick;
110
Jeff Dikefe2cc532008-05-12 14:02:00 -0700111 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
Jeff Dike364e3a32007-11-28 16:21:51 -0800129static 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;
Jeff Dikefe2cc532008-05-12 14:02:00 -0700151
152 start_usecs -= skew / UM_NSEC_PER_USEC;
Jeff Dike06e1e4f2008-06-05 22:46:10 -0700153 if (start_usecs < 0)
154 start_usecs = 0;
155
Jeff Dike364e3a32007-11-28 16:21:51 -0800156 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
Jeff Dikeb160fb62007-10-16 01:27:26 -0700167void idle_sleep(unsigned long long nsecs)
168{
Jeff Dike364e3a32007-11-28 16:21:51 -0800169 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;
Jeff Dikefe2cc532008-05-12 14:02:00 -0700178
179 nsecs = sleep_time(nsecs);
Jeff Dike364e3a32007-11-28 16:21:51 -0800180 ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC,
181 .tv_nsec = nsecs % UM_NSEC_PER_SEC });
Jeff Dikeb160fb62007-10-16 01:27:26 -0700182
183 if (nanosleep(&ts, &ts) == 0)
Jeff Dikefe2cc532008-05-12 14:02:00 -0700184 deliver_alarm();
Jeff Dike364e3a32007-11-28 16:21:51 -0800185 after_sleep_interval(&ts);
Gennady Sharapovcff65c42006-01-18 17:42:42 -0800186}