/*
- * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
+#include <stddef.h>
+#include <errno.h>
+#include <signal.h>
#include <time.h>
#include <sys/time.h>
-#include <signal.h>
-#include <errno.h>
-#include "user_util.h"
-#include "kern_util.h"
-#include "user.h"
-#include "process.h"
#include "kern_constants.h"
+#include "kern_util.h"
#include "os.h"
+#include "process.h"
+#include "user.h"
-static void set_interval(int timer_type)
+int set_interval(void)
{
- int usec = 1000000/hz();
+ int usec = UM_USEC_PER_SEC / UM_HZ;
struct itimerval interval = ((struct itimerval) { { 0, usec },
{ 0, usec } });
- if(setitimer(timer_type, &interval, NULL) == -1)
- panic("setitimer failed - errno = %d\n", errno);
+ if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
+ return -errno;
+
+ return 0;
}
-void enable_timer(void)
+int timer_one_shot(int ticks)
{
- set_interval(ITIMER_VIRTUAL);
+ unsigned long usec = ticks * UM_USEC_PER_SEC / UM_HZ;
+ unsigned long sec = usec / UM_USEC_PER_SEC;
+ struct itimerval interval;
+
+ usec %= UM_USEC_PER_SEC;
+ interval = ((struct itimerval) { { 0, 0 }, { sec, usec } });
+
+ if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
+ return -errno;
+
+ return 0;
}
-void disable_timer(void)
+/**
+ * timeval_to_ns - Convert timeval to nanoseconds
+ * @ts: pointer to the timeval variable to be converted
+ *
+ * Returns the scalar nanosecond representation of the timeval
+ * parameter.
+ *
+ * Ripped from linux/time.h because it's a kernel header, and thus
+ * unusable from here.
+ */
+static inline long long timeval_to_ns(const struct timeval *tv)
{
- struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
- if((setitimer(ITIMER_VIRTUAL, &disable, NULL) < 0) ||
- (setitimer(ITIMER_REAL, &disable, NULL) < 0))
- printk("disnable_timer - setitimer failed, errno = %d\n",
- errno);
- /* If there are signals already queued, after unblocking ignore them */
- set_handler(SIGALRM, SIG_IGN, 0, -1);
- set_handler(SIGVTALRM, SIG_IGN, 0, -1);
+ return ((long long) tv->tv_sec * UM_NSEC_PER_SEC) +
+ tv->tv_usec * UM_NSEC_PER_USEC;
}
-void switch_timers(int to_real)
+long long disable_timer(void)
{
- struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
- struct itimerval enable = ((struct itimerval) { { 0, 1000000/hz() },
- { 0, 1000000/hz() }});
- int old, new;
-
- if(to_real){
- old = ITIMER_VIRTUAL;
- new = ITIMER_REAL;
- }
- else {
- old = ITIMER_REAL;
- new = ITIMER_VIRTUAL;
+ struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
+ int remain, max = UM_NSEC_PER_SEC / UM_HZ;
+
+ if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
+ printk(UM_KERN_ERR "disable_timer - setitimer failed, "
+ "errno = %d\n", errno);
+
+ remain = timeval_to_ns(&time.it_value);
+ if (remain > max)
+ remain = max;
+
+ return remain;
+}
+
+long long os_nsecs(void)
+{
+ struct timeval tv;
+
+ gettimeofday(&tv, NULL);
+ return timeval_to_ns(&tv);
+}
+
+#ifdef UML_CONFIG_NO_HZ
+static int after_sleep_interval(struct timespec *ts)
+{
+ return 0;
+}
+
+static void deliver_alarm(void)
+{
+ alarm_handler(SIGVTALRM, NULL);
+}
+
+static unsigned long long sleep_time(unsigned long long nsecs)
+{
+ return nsecs;
+}
+
+#else
+unsigned long long last_tick;
+unsigned long long skew;
+
+static void deliver_alarm(void)
+{
+ unsigned long long this_tick = os_nsecs();
+ int one_tick = UM_NSEC_PER_SEC / UM_HZ;
+
+ /* Protection against the host's time going backwards */
+ if ((last_tick != 0) && (this_tick < last_tick))
+ this_tick = last_tick;
+
+ if (last_tick == 0)
+ last_tick = this_tick - one_tick;
+
+ skew += this_tick - last_tick;
+
+ while (skew >= one_tick) {
+ alarm_handler(SIGVTALRM, NULL);
+ skew -= one_tick;
}
- if((setitimer(old, &disable, NULL) < 0) ||
- (setitimer(new, &enable, NULL)))
- printk("switch_timers - setitimer failed, errno = %d\n",
- errno);
+ last_tick = this_tick;
}
-#ifdef UML_CONFIG_MODE_TT
-void uml_idle_timer(void)
+static unsigned long long sleep_time(unsigned long long nsecs)
{
- if(signal(SIGVTALRM, SIG_IGN) == SIG_ERR)
- panic("Couldn't unset SIGVTALRM handler");
+ return nsecs > skew ? nsecs - skew : 0;
+}
- set_handler(SIGALRM, (__sighandler_t) alarm_handler,
- SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
- set_interval(ITIMER_REAL);
+static inline long long timespec_to_us(const struct timespec *ts)
+{
+ return ((long long) ts->tv_sec * UM_USEC_PER_SEC) +
+ ts->tv_nsec / UM_NSEC_PER_USEC;
}
-#endif
-unsigned long long os_nsecs(void)
+static int after_sleep_interval(struct timespec *ts)
{
+ int usec = UM_USEC_PER_SEC / UM_HZ;
+ long long start_usecs = timespec_to_us(ts);
struct timeval tv;
+ struct itimerval interval;
- gettimeofday(&tv, NULL);
- return((unsigned long long) tv.tv_sec * BILLION + tv.tv_usec * 1000);
+ /*
+ * It seems that rounding can increase the value returned from
+ * setitimer to larger than the one passed in. Over time,
+ * this will cause the remaining time to be greater than the
+ * tick interval. If this happens, then just reduce the first
+ * tick to the interval value.
+ */
+ if (start_usecs > usec)
+ start_usecs = usec;
+
+ start_usecs -= skew / UM_NSEC_PER_USEC;
+ if (start_usecs < 0)
+ start_usecs = 0;
+
+ tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC,
+ .tv_usec = start_usecs % UM_USEC_PER_SEC });
+ interval = ((struct itimerval) { { 0, usec }, tv });
+
+ if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
+ return -errno;
+
+ return 0;
}
+#endif
-void idle_sleep(int secs)
+void idle_sleep(unsigned long long nsecs)
{
struct timespec ts;
- ts.tv_sec = secs;
- ts.tv_nsec = 0;
- nanosleep(&ts, NULL);
-}
+ /*
+ * nsecs can come in as zero, in which case, this starts a
+ * busy loop. To prevent this, reset nsecs to the tick
+ * interval if it is zero.
+ */
+ if (nsecs == 0)
+ nsecs = UM_NSEC_PER_SEC / UM_HZ;
-void user_time_init(void)
-{
- set_interval(ITIMER_VIRTUAL);
+ nsecs = sleep_time(nsecs);
+ ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC,
+ .tv_nsec = nsecs % UM_NSEC_PER_SEC });
+
+ if (nanosleep(&ts, &ts) == 0)
+ deliver_alarm();
+ after_sleep_interval(&ts);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff