136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/*
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <stddef.h>
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#include <errno.h>
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#include <signal.h>
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#include <time.h>
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#include <sys/time.h>
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#include "kern_constants.h"
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#include "os.h"
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#include "user.h"
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int set_interval(void)
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{
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int usec = UM_USEC_PER_SEC / UM_HZ;
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struct itimerval interval = ((struct itimerval) { { 0, usec },
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{ 0, usec } });
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if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
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return -errno;
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return 0;
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}
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int timer_one_shot(int ticks)
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{
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unsigned long usec = ticks * UM_USEC_PER_SEC / UM_HZ;
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unsigned long sec = usec / UM_USEC_PER_SEC;
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struct itimerval interval;
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usec %= UM_USEC_PER_SEC;
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interval = ((struct itimerval) { { 0, 0 }, { sec, usec } });
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if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
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return -errno;
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return 0;
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}
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/**
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* timeval_to_ns - Convert timeval to nanoseconds
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* @ts: pointer to the timeval variable to be converted
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*
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* Returns the scalar nanosecond representation of the timeval
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* parameter.
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*
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* Ripped from linux/time.h because it's a kernel header, and thus
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* unusable from here.
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*/
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static inline long long timeval_to_ns(const struct timeval *tv)
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{
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return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
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tv->tv_usec * UM_NSEC_PER_USEC;
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}
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long long disable_timer(void)
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{
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struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
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if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
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printk(UM_KERN_ERR "disable_timer - setitimer failed, "
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"errno = %d\n", errno);
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return timeval_to_ns(&time.it_value);
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}
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long long os_nsecs(void)
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{
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struct timeval tv;
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gettimeofday(&tv, NULL);
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return timeval_to_ns(&tv);
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}
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#ifdef UML_CONFIG_NO_HZ
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static int after_sleep_interval(struct timespec *ts)
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{
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return 0;
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}
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#else
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static inline long long timespec_to_us(const struct timespec *ts)
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{
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return ((long long) ts->tv_sec * UM_USEC_PER_SEC) +
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ts->tv_nsec / UM_NSEC_PER_USEC;
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}
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static int after_sleep_interval(struct timespec *ts)
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{
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int usec = UM_USEC_PER_SEC / UM_HZ;
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long long start_usecs = timespec_to_us(ts);
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struct timeval tv;
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struct itimerval interval;
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/*
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* It seems that rounding can increase the value returned from
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* setitimer to larger than the one passed in. Over time,
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* this will cause the remaining time to be greater than the
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* tick interval. If this happens, then just reduce the first
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* tick to the interval value.
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*/
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if (start_usecs > usec)
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start_usecs = usec;
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tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC,
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.tv_usec = start_usecs % UM_USEC_PER_SEC });
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interval = ((struct itimerval) { { 0, usec }, tv });
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if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
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return -errno;
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return 0;
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}
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#endif
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extern void alarm_handler(int sig, struct sigcontext *sc);
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void idle_sleep(unsigned long long nsecs)
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{
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struct timespec ts;
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/*
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* nsecs can come in as zero, in which case, this starts a
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* busy loop. To prevent this, reset nsecs to the tick
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* interval if it is zero.
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*/
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if (nsecs == 0)
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nsecs = UM_NSEC_PER_SEC / UM_HZ;
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ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC,
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.tv_nsec = nsecs % UM_NSEC_PER_SEC });
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if (nanosleep(&ts, &ts) == 0)
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alarm_handler(SIGVTALRM, NULL);
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after_sleep_interval(&ts);
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}
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