#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/mm.h>
+#include <linux/sched.h>
#include <linux/sysdev.h>
#include <linux/clocksource.h>
#include <linux/jiffies.h>
#include <linux/time.h>
#include <linux/tick.h>
+#include <linux/stop_machine.h>
+
+/* Structure holding internal timekeeping values. */
+struct timekeeper {
+ /* Current clocksource used for timekeeping. */
+ struct clocksource *clock;
+ /* The shift value of the current clocksource. */
+ int shift;
+
+ /* Number of clock cycles in one NTP interval. */
+ cycle_t cycle_interval;
+ /* Number of clock shifted nano seconds in one NTP interval. */
+ u64 xtime_interval;
+ /* Raw nano seconds accumulated per NTP interval. */
+ u32 raw_interval;
+
+ /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */
+ u64 xtime_nsec;
+ /* Difference between accumulated time and NTP time in ntp
+ * shifted nano seconds. */
+ s64 ntp_error;
+ /* Shift conversion between clock shifted nano seconds and
+ * ntp shifted nano seconds. */
+ int ntp_error_shift;
+ /* NTP adjusted clock multiplier */
+ u32 mult;
+};
+
+struct timekeeper timekeeper;
+
+/**
+ * timekeeper_setup_internals - Set up internals to use clocksource clock.
+ *
+ * @clock: Pointer to clocksource.
+ *
+ * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
+ * pair and interval request.
+ *
+ * Unless you're the timekeeping code, you should not be using this!
+ */
+static void timekeeper_setup_internals(struct clocksource *clock)
+{
+ cycle_t interval;
+ u64 tmp;
+
+ timekeeper.clock = clock;
+ clock->cycle_last = clock->read(clock);
+
+ /* Do the ns -> cycle conversion first, using original mult */
+ tmp = NTP_INTERVAL_LENGTH;
+ tmp <<= clock->shift;
+ tmp += clock->mult/2;
+ do_div(tmp, clock->mult);
+ if (tmp == 0)
+ tmp = 1;
+
+ interval = (cycle_t) tmp;
+ timekeeper.cycle_interval = interval;
+
+ /* Go back from cycles -> shifted ns */
+ timekeeper.xtime_interval = (u64) interval * clock->mult;
+ timekeeper.raw_interval =
+ ((u64) interval * clock->mult) >> clock->shift;
+
+ timekeeper.xtime_nsec = 0;
+ timekeeper.shift = clock->shift;
+
+ timekeeper.ntp_error = 0;
+ timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+
+ /*
+ * The timekeeper keeps its own mult values for the currently
+ * active clocksource. These value will be adjusted via NTP
+ * to counteract clock drifting.
+ */
+ timekeeper.mult = clock->mult;
+}
+
+/* Timekeeper helper functions. */
+static inline s64 timekeeping_get_ns(void)
+{
+ cycle_t cycle_now, cycle_delta;
+ struct clocksource *clock;
+
+ /* read clocksource: */
+ clock = timekeeper.clock;
+ cycle_now = clock->read(clock);
+ /* calculate the delta since the last update_wall_time: */
+ cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+ /* return delta convert to nanoseconds using ntp adjusted mult. */
+ return clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+ timekeeper.shift);
+}
+
+static inline s64 timekeeping_get_ns_raw(void)
+{
+ cycle_t cycle_now, cycle_delta;
+ struct clocksource *clock;
+
+ /* read clocksource: */
+ clock = timekeeper.clock;
+ cycle_now = clock->read(clock);
+
+ /* calculate the delta since the last update_wall_time: */
+ cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+ /* return delta convert to nanoseconds using ntp adjusted mult. */
+ return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
+}
/*
* This read-write spinlock protects us from races in SMP while
- * playing with xtime and avenrun.
+ * playing with xtime.
*/
-__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
-
-EXPORT_SYMBOL(xtime_lock);
+__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
/*
*/
struct timespec xtime __attribute__ ((aligned (16)));
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
-static unsigned long total_sleep_time; /* seconds */
-EXPORT_SYMBOL(xtime);
+static struct timespec total_sleep_time;
+
+/*
+ * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock.
+ */
+struct timespec raw_time;
+/* flag for if timekeeping is suspended */
+int __read_mostly timekeeping_suspended;
-#ifdef CONFIG_NO_HZ
static struct timespec xtime_cache __attribute__ ((aligned (16)));
-static inline void update_xtime_cache(u64 nsec)
+void update_xtime_cache(u64 nsec)
{
xtime_cache = xtime;
timespec_add_ns(&xtime_cache, nsec);
}
-#else
-#define xtime_cache xtime
-/* We do *not* want to evaluate the argument for this case */
-#define update_xtime_cache(n) do { } while (0)
-#endif
-
-static struct clocksource *clock; /* pointer to current clocksource */
+/* must hold xtime_lock */
+void timekeeping_leap_insert(int leapsecond)
+{
+ xtime.tv_sec += leapsecond;
+ wall_to_monotonic.tv_sec -= leapsecond;
+ update_vsyscall(&xtime, timekeeper.clock);
+}
#ifdef CONFIG_GENERIC_TIME
+
/**
- * __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
+ * timekeeping_forward_now - update clock to the current time
*
- * private function, must hold xtime_lock lock when being
- * called. Returns the number of nanoseconds since the
- * last call to update_wall_time() (adjusted by NTP scaling)
+ * Forward the current clock to update its state since the last call to
+ * update_wall_time(). This is useful before significant clock changes,
+ * as it avoids having to deal with this time offset explicitly.
*/
-static inline s64 __get_nsec_offset(void)
+static void timekeeping_forward_now(void)
{
cycle_t cycle_now, cycle_delta;
- s64 ns_offset;
-
- /* read clocksource: */
- cycle_now = clocksource_read(clock);
+ struct clocksource *clock;
+ s64 nsec;
- /* calculate the delta since the last update_wall_time: */
+ clock = timekeeper.clock;
+ cycle_now = clock->read(clock);
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+ clock->cycle_last = cycle_now;
+
+ nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+ timekeeper.shift);
+
+ /* If arch requires, add in gettimeoffset() */
+ nsec += arch_gettimeoffset();
- /* convert to nanoseconds: */
- ns_offset = cyc2ns(clock, cycle_delta);
+ timespec_add_ns(&xtime, nsec);
- return ns_offset;
+ nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
+ timespec_add_ns(&raw_time, nsec);
}
/**
- * __get_realtime_clock_ts - Returns the time of day in a timespec
+ * getnstimeofday - Returns the time of day in a timespec
* @ts: pointer to the timespec to be set
*
- * Returns the time of day in a timespec. Used by
- * do_gettimeofday() and get_realtime_clock_ts().
+ * Returns the time of day in a timespec.
*/
-static inline void __get_realtime_clock_ts(struct timespec *ts)
+void getnstimeofday(struct timespec *ts)
{
unsigned long seq;
s64 nsecs;
+ WARN_ON(timekeeping_suspended);
+
do {
seq = read_seqbegin(&xtime_lock);
*ts = xtime;
- nsecs = __get_nsec_offset();
+ nsecs = timekeeping_get_ns();
+
+ /* If arch requires, add in gettimeoffset() */
+ nsecs += arch_gettimeoffset();
} while (read_seqretry(&xtime_lock, seq));
timespec_add_ns(ts, nsecs);
}
+EXPORT_SYMBOL(getnstimeofday);
+
+ktime_t ktime_get(void)
+{
+ unsigned int seq;
+ s64 secs, nsecs;
+
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ secs = xtime.tv_sec + wall_to_monotonic.tv_sec;
+ nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec;
+ nsecs += timekeeping_get_ns();
+
+ } while (read_seqretry(&xtime_lock, seq));
+ /*
+ * Use ktime_set/ktime_add_ns to create a proper ktime on
+ * 32-bit architectures without CONFIG_KTIME_SCALAR.
+ */
+ return ktime_add_ns(ktime_set(secs, 0), nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get);
+
/**
- * getnstimeofday - Returns the time of day in a timespec
- * @ts: pointer to the timespec to be set
+ * ktime_get_ts - get the monotonic clock in timespec format
+ * @ts: pointer to timespec variable
*
- * Returns the time of day in a timespec.
+ * The function calculates the monotonic clock from the realtime
+ * clock and the wall_to_monotonic offset and stores the result
+ * in normalized timespec format in the variable pointed to by @ts.
*/
-void getnstimeofday(struct timespec *ts)
+void ktime_get_ts(struct timespec *ts)
{
- __get_realtime_clock_ts(ts);
-}
+ struct timespec tomono;
+ unsigned int seq;
+ s64 nsecs;
-EXPORT_SYMBOL(getnstimeofday);
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ *ts = xtime;
+ tomono = wall_to_monotonic;
+ nsecs = timekeeping_get_ns();
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
+ ts->tv_nsec + tomono.tv_nsec + nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get_ts);
/**
* do_gettimeofday - Returns the time of day in a timeval
* @tv: pointer to the timeval to be set
*
- * NOTE: Users should be converted to using get_realtime_clock_ts()
+ * NOTE: Users should be converted to using getnstimeofday()
*/
void do_gettimeofday(struct timeval *tv)
{
struct timespec now;
- __get_realtime_clock_ts(&now);
+ getnstimeofday(&now);
tv->tv_sec = now.tv_sec;
tv->tv_usec = now.tv_nsec/1000;
}
*/
int do_settimeofday(struct timespec *tv)
{
+ struct timespec ts_delta;
unsigned long flags;
- time_t wtm_sec, sec = tv->tv_sec;
- long wtm_nsec, nsec = tv->tv_nsec;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irqsave(&xtime_lock, flags);
- nsec -= __get_nsec_offset();
+ timekeeping_forward_now();
+
+ ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec;
+ ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec;
+ wall_to_monotonic = timespec_sub(wall_to_monotonic, ts_delta);
- wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
- wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
+ xtime = *tv;
- set_normalized_timespec(&xtime, sec, nsec);
- set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
+ update_xtime_cache(0);
- clock->error = 0;
+ timekeeper.ntp_error = 0;
ntp_clear();
- update_vsyscall(&xtime, clock);
+ update_vsyscall(&xtime, timekeeper.clock);
write_sequnlock_irqrestore(&xtime_lock, flags);
*
* Accumulates current time interval and initializes new clocksource
*/
-static void change_clocksource(void)
+static int change_clocksource(void *data)
{
- struct clocksource *new;
- cycle_t now;
- u64 nsec;
+ struct clocksource *new, *old;
- new = clocksource_get_next();
+ new = (struct clocksource *) data;
- if (clock == new)
+ timekeeping_forward_now();
+ if (!new->enable || new->enable(new) == 0) {
+ old = timekeeper.clock;
+ timekeeper_setup_internals(new);
+ if (old->disable)
+ old->disable(old);
+ }
+ return 0;
+}
+
+/**
+ * timekeeping_notify - Install a new clock source
+ * @clock: pointer to the clock source
+ *
+ * This function is called from clocksource.c after a new, better clock
+ * source has been registered. The caller holds the clocksource_mutex.
+ */
+void timekeeping_notify(struct clocksource *clock)
+{
+ if (timekeeper.clock == clock)
return;
+ stop_machine(change_clocksource, clock, NULL);
+ tick_clock_notify();
+}
- now = clocksource_read(new);
- nsec = __get_nsec_offset();
- timespec_add_ns(&xtime, nsec);
+#else /* GENERIC_TIME */
- clock = new;
- clock->cycle_last = now;
+static inline void timekeeping_forward_now(void) { }
- clock->error = 0;
- clock->xtime_nsec = 0;
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
+/**
+ * ktime_get - get the monotonic time in ktime_t format
+ *
+ * returns the time in ktime_t format
+ */
+ktime_t ktime_get(void)
+{
+ struct timespec now;
- tick_clock_notify();
+ ktime_get_ts(&now);
- printk(KERN_INFO "Time: %s clocksource has been installed.\n",
- clock->name);
+ return timespec_to_ktime(now);
}
-#else
-static inline void change_clocksource(void) { }
-#endif
+EXPORT_SYMBOL_GPL(ktime_get);
+
+/**
+ * ktime_get_ts - get the monotonic clock in timespec format
+ * @ts: pointer to timespec variable
+ *
+ * The function calculates the monotonic clock from the realtime
+ * clock and the wall_to_monotonic offset and stores the result
+ * in normalized timespec format in the variable pointed to by @ts.
+ */
+void ktime_get_ts(struct timespec *ts)
+{
+ struct timespec tomono;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ getnstimeofday(ts);
+ tomono = wall_to_monotonic;
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
+ ts->tv_nsec + tomono.tv_nsec);
+}
+EXPORT_SYMBOL_GPL(ktime_get_ts);
+
+#endif /* !GENERIC_TIME */
+
+/**
+ * ktime_get_real - get the real (wall-) time in ktime_t format
+ *
+ * returns the time in ktime_t format
+ */
+ktime_t ktime_get_real(void)
+{
+ struct timespec now;
+
+ getnstimeofday(&now);
+
+ return timespec_to_ktime(now);
+}
+EXPORT_SYMBOL_GPL(ktime_get_real);
+
+/**
+ * getrawmonotonic - Returns the raw monotonic time in a timespec
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the raw monotonic time (completely un-modified by ntp)
+ */
+void getrawmonotonic(struct timespec *ts)
+{
+ unsigned long seq;
+ s64 nsecs;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ nsecs = timekeeping_get_ns_raw();
+ *ts = raw_time;
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ timespec_add_ns(ts, nsecs);
+}
+EXPORT_SYMBOL(getrawmonotonic);
+
/**
- * timekeeping_is_continuous - check to see if timekeeping is free running
+ * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
*/
-int timekeeping_is_continuous(void)
+int timekeeping_valid_for_hres(void)
{
unsigned long seq;
int ret;
do {
seq = read_seqbegin(&xtime_lock);
- ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
+ ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
} while (read_seqretry(&xtime_lock, seq));
}
/**
- * read_persistent_clock - Return time in seconds from the persistent clock.
+ * read_persistent_clock - Return time from the persistent clock.
*
* Weak dummy function for arches that do not yet support it.
- * Returns seconds from epoch using the battery backed persistent clock.
- * Returns zero if unsupported.
+ * Reads the time from the battery backed persistent clock.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
*
* XXX - Do be sure to remove it once all arches implement it.
*/
-unsigned long __attribute__((weak)) read_persistent_clock(void)
+void __attribute__((weak)) read_persistent_clock(struct timespec *ts)
{
- return 0;
+ ts->tv_sec = 0;
+ ts->tv_nsec = 0;
+}
+
+/**
+ * read_boot_clock - Return time of the system start.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Function to read the exact time the system has been started.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
+ *
+ * XXX - Do be sure to remove it once all arches implement it.
+ */
+void __attribute__((weak)) read_boot_clock(struct timespec *ts)
+{
+ ts->tv_sec = 0;
+ ts->tv_nsec = 0;
}
/*
*/
void __init timekeeping_init(void)
{
+ struct clocksource *clock;
unsigned long flags;
- unsigned long sec = read_persistent_clock();
+ struct timespec now, boot;
+
+ read_persistent_clock(&now);
+ read_boot_clock(&boot);
write_seqlock_irqsave(&xtime_lock, flags);
- ntp_clear();
+ ntp_init();
- clock = clocksource_get_next();
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
- clock->cycle_last = clocksource_read(clock);
+ clock = clocksource_default_clock();
+ if (clock->enable)
+ clock->enable(clock);
+ timekeeper_setup_internals(clock);
- xtime.tv_sec = sec;
- xtime.tv_nsec = 0;
+ xtime.tv_sec = now.tv_sec;
+ xtime.tv_nsec = now.tv_nsec;
+ raw_time.tv_sec = 0;
+ raw_time.tv_nsec = 0;
+ if (boot.tv_sec == 0 && boot.tv_nsec == 0) {
+ boot.tv_sec = xtime.tv_sec;
+ boot.tv_nsec = xtime.tv_nsec;
+ }
set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
- total_sleep_time = 0;
-
+ -boot.tv_sec, -boot.tv_nsec);
+ update_xtime_cache(0);
+ total_sleep_time.tv_sec = 0;
+ total_sleep_time.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
}
-/* flag for if timekeeping is suspended */
-static int timekeeping_suspended;
/* time in seconds when suspend began */
-static unsigned long timekeeping_suspend_time;
+static struct timespec timekeeping_suspend_time;
/**
* timekeeping_resume - Resumes the generic timekeeping subsystem.
static int timekeeping_resume(struct sys_device *dev)
{
unsigned long flags;
- unsigned long now = read_persistent_clock();
+ struct timespec ts;
+
+ read_persistent_clock(&ts);
clocksource_resume();
write_seqlock_irqsave(&xtime_lock, flags);
- if (now && (now > timekeeping_suspend_time)) {
- unsigned long sleep_length = now - timekeeping_suspend_time;
-
- xtime.tv_sec += sleep_length;
- wall_to_monotonic.tv_sec -= sleep_length;
- total_sleep_time += sleep_length;
+ if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
+ ts = timespec_sub(ts, timekeeping_suspend_time);
+ xtime = timespec_add_safe(xtime, ts);
+ wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
+ total_sleep_time = timespec_add_safe(total_sleep_time, ts);
}
+ update_xtime_cache(0);
/* re-base the last cycle value */
- clock->cycle_last = clocksource_read(clock);
- clock->error = 0;
+ timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
+ timekeeper.ntp_error = 0;
timekeeping_suspended = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
{
unsigned long flags;
+ read_persistent_clock(&timekeeping_suspend_time);
+
write_seqlock_irqsave(&xtime_lock, flags);
+ timekeeping_forward_now();
timekeeping_suspended = 1;
- timekeeping_suspend_time = read_persistent_clock();
write_sequnlock_irqrestore(&xtime_lock, flags);
clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
/* sysfs resume/suspend bits for timekeeping */
static struct sysdev_class timekeeping_sysclass = {
+ .name = "timekeeping",
.resume = timekeeping_resume,
.suspend = timekeeping_suspend,
- set_kset_name("timekeeping"),
};
static struct sys_device device_timer = {
* If the error is already larger, we look ahead even further
* to compensate for late or lost adjustments.
*/
-static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
+static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval,
s64 *offset)
{
s64 tick_error, i;
* with losing too many ticks, otherwise we would overadjust and
* produce an even larger error. The smaller the adjustment the
* faster we try to adjust for it, as lost ticks can do less harm
- * here. This is tuned so that an error of about 1 msec is adusted
+ * here. This is tuned so that an error of about 1 msec is adjusted
* within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
*/
- error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
+ error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
error2 = abs(error2);
for (look_ahead = 0; error2 > 0; look_ahead++)
error2 >>= 2;
* Now calculate the error in (1 << look_ahead) ticks, but first
* remove the single look ahead already included in the error.
*/
- tick_error = current_tick_length() >>
- (TICK_LENGTH_SHIFT - clock->shift + 1);
- tick_error -= clock->xtime_interval >> 1;
+ tick_error = tick_length >> (timekeeper.ntp_error_shift + 1);
+ tick_error -= timekeeper.xtime_interval >> 1;
error = ((error - tick_error) >> look_ahead) + tick_error;
/* Finally calculate the adjustment shift value. */
* this is optimized for the most common adjustments of -1,0,1,
* for other values we can do a bit more work.
*/
-static void clocksource_adjust(s64 offset)
+static void timekeeping_adjust(s64 offset)
{
- s64 error, interval = clock->cycle_interval;
+ s64 error, interval = timekeeper.cycle_interval;
int adj;
- error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
+ error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1);
if (error > interval) {
error >>= 2;
if (likely(error <= interval))
adj = 1;
else
- adj = clocksource_bigadjust(error, &interval, &offset);
+ adj = timekeeping_bigadjust(error, &interval, &offset);
} else if (error < -interval) {
error >>= 2;
if (likely(error >= -interval)) {
interval = -interval;
offset = -offset;
} else
- adj = clocksource_bigadjust(error, &interval, &offset);
+ adj = timekeeping_bigadjust(error, &interval, &offset);
} else
return;
- clock->mult += adj;
- clock->xtime_interval += interval;
- clock->xtime_nsec -= offset;
- clock->error -= (interval - offset) <<
- (TICK_LENGTH_SHIFT - clock->shift);
+ timekeeper.mult += adj;
+ timekeeper.xtime_interval += interval;
+ timekeeper.xtime_nsec -= offset;
+ timekeeper.ntp_error -= (interval - offset) <<
+ timekeeper.ntp_error_shift;
}
/**
*/
void update_wall_time(void)
{
+ struct clocksource *clock;
cycle_t offset;
+ u64 nsecs;
/* Make sure we're fully resumed: */
if (unlikely(timekeeping_suspended))
return;
+ clock = timekeeper.clock;
#ifdef CONFIG_GENERIC_TIME
- offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
+ offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
#else
- offset = clock->cycle_interval;
+ offset = timekeeper.cycle_interval;
#endif
- clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
+ timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift;
/* normally this loop will run just once, however in the
* case of lost or late ticks, it will accumulate correctly.
*/
- while (offset >= clock->cycle_interval) {
+ while (offset >= timekeeper.cycle_interval) {
+ u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift;
+
/* accumulate one interval */
- clock->xtime_nsec += clock->xtime_interval;
- clock->cycle_last += clock->cycle_interval;
- offset -= clock->cycle_interval;
+ offset -= timekeeper.cycle_interval;
+ clock->cycle_last += timekeeper.cycle_interval;
- if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
- clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
+ timekeeper.xtime_nsec += timekeeper.xtime_interval;
+ if (timekeeper.xtime_nsec >= nsecps) {
+ timekeeper.xtime_nsec -= nsecps;
xtime.tv_sec++;
second_overflow();
}
+ raw_time.tv_nsec += timekeeper.raw_interval;
+ if (raw_time.tv_nsec >= NSEC_PER_SEC) {
+ raw_time.tv_nsec -= NSEC_PER_SEC;
+ raw_time.tv_sec++;
+ }
+
/* accumulate error between NTP and clock interval */
- clock->error += current_tick_length();
- clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
+ timekeeper.ntp_error += tick_length;
+ timekeeper.ntp_error -= timekeeper.xtime_interval <<
+ timekeeper.ntp_error_shift;
}
/* correct the clock when NTP error is too big */
- clocksource_adjust(offset);
+ timekeeping_adjust(offset);
+
+ /*
+ * Since in the loop above, we accumulate any amount of time
+ * in xtime_nsec over a second into xtime.tv_sec, its possible for
+ * xtime_nsec to be fairly small after the loop. Further, if we're
+ * slightly speeding the clocksource up in timekeeping_adjust(),
+ * its possible the required corrective factor to xtime_nsec could
+ * cause it to underflow.
+ *
+ * Now, we cannot simply roll the accumulated second back, since
+ * the NTP subsystem has been notified via second_overflow. So
+ * instead we push xtime_nsec forward by the amount we underflowed,
+ * and add that amount into the error.
+ *
+ * We'll correct this error next time through this function, when
+ * xtime_nsec is not as small.
+ */
+ if (unlikely((s64)timekeeper.xtime_nsec < 0)) {
+ s64 neg = -(s64)timekeeper.xtime_nsec;
+ timekeeper.xtime_nsec = 0;
+ timekeeper.ntp_error += neg << timekeeper.ntp_error_shift;
+ }
- /* store full nanoseconds into xtime */
- xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
- clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
+ /* store full nanoseconds into xtime after rounding it up and
+ * add the remainder to the error difference.
+ */
+ xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1;
+ timekeeper.xtime_nsec -= (s64) xtime.tv_nsec << timekeeper.shift;
+ timekeeper.ntp_error += timekeeper.xtime_nsec <<
+ timekeeper.ntp_error_shift;
- update_xtime_cache(cyc2ns(clock, offset));
+ nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
+ update_xtime_cache(nsecs);
/* check to see if there is a new clocksource to use */
- change_clocksource();
- update_vsyscall(&xtime, clock);
+ update_vsyscall(&xtime, timekeeper.clock);
}
/**
*/
void getboottime(struct timespec *ts)
{
- set_normalized_timespec(ts,
- - (wall_to_monotonic.tv_sec + total_sleep_time),
- - wall_to_monotonic.tv_nsec);
+ struct timespec boottime = {
+ .tv_sec = wall_to_monotonic.tv_sec + total_sleep_time.tv_sec,
+ .tv_nsec = wall_to_monotonic.tv_nsec + total_sleep_time.tv_nsec
+ };
+
+ set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
}
/**
*/
void monotonic_to_bootbased(struct timespec *ts)
{
- ts->tv_sec += total_sleep_time;
+ *ts = timespec_add_safe(*ts, total_sleep_time);
}
unsigned long get_seconds(void)
}
EXPORT_SYMBOL(get_seconds);
+struct timespec __current_kernel_time(void)
+{
+ return xtime_cache;
+}
struct timespec current_kernel_time(void)
{
return now;
}
EXPORT_SYMBOL(current_kernel_time);
+
+struct timespec get_monotonic_coarse(void)
+{
+ struct timespec now, mono;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ now = xtime_cache;
+ mono = wall_to_monotonic;
+ } while (read_seqretry(&xtime_lock, seq));
+
+ set_normalized_timespec(&now, now.tv_sec + mono.tv_sec,
+ now.tv_nsec + mono.tv_nsec);
+ return now;
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff