mirror of
https://github.com/adulau/aha.git
synced 2024-12-28 03:36:19 +00:00
ntp: handle leap second via timer
Remove the leap second handling from second_overflow(), which doesn't have to check for it every second anymore. With CONFIG_NO_HZ this also makes sure the leap second is handled close to the full second. Additionally this makes it possible to abort a leap second properly by resetting the STA_INS/STA_DEL status bits. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
8383c42399
commit
7dffa3c673
4 changed files with 96 additions and 46 deletions
|
@ -93,6 +93,8 @@ struct clocksource {
|
|||
#endif
|
||||
};
|
||||
|
||||
extern struct clocksource *clock; /* current clocksource */
|
||||
|
||||
/*
|
||||
* Clock source flags bits::
|
||||
*/
|
||||
|
|
|
@ -212,6 +212,7 @@ extern long time_esterror; /* estimated error */
|
|||
|
||||
extern long time_adjust; /* The amount of adjtime left */
|
||||
|
||||
extern void ntp_init(void);
|
||||
extern void ntp_clear(void);
|
||||
|
||||
/**
|
||||
|
|
|
@ -16,6 +16,7 @@
|
|||
#include <linux/hrtimer.h>
|
||||
#include <linux/capability.h>
|
||||
#include <linux/math64.h>
|
||||
#include <linux/clocksource.h>
|
||||
#include <asm/timex.h>
|
||||
|
||||
/*
|
||||
|
@ -26,6 +27,8 @@ unsigned long tick_nsec; /* ACTHZ period (nsec) */
|
|||
u64 tick_length;
|
||||
static u64 tick_length_base;
|
||||
|
||||
static struct hrtimer leap_timer;
|
||||
|
||||
#define MAX_TICKADJ 500 /* microsecs */
|
||||
#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
|
||||
NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
|
||||
|
@ -119,6 +122,54 @@ void ntp_clear(void)
|
|||
time_offset = 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Leap second processing. If in leap-insert state at the end of the
|
||||
* day, the system clock is set back one second; if in leap-delete
|
||||
* state, the system clock is set ahead one second.
|
||||
*/
|
||||
static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
|
||||
{
|
||||
enum hrtimer_restart res = HRTIMER_NORESTART;
|
||||
|
||||
write_seqlock_irq(&xtime_lock);
|
||||
|
||||
switch (time_state) {
|
||||
case TIME_OK:
|
||||
break;
|
||||
case TIME_INS:
|
||||
xtime.tv_sec--;
|
||||
wall_to_monotonic.tv_sec++;
|
||||
time_state = TIME_OOP;
|
||||
printk(KERN_NOTICE "Clock: "
|
||||
"inserting leap second 23:59:60 UTC\n");
|
||||
leap_timer.expires = ktime_add_ns(leap_timer.expires,
|
||||
NSEC_PER_SEC);
|
||||
res = HRTIMER_RESTART;
|
||||
break;
|
||||
case TIME_DEL:
|
||||
xtime.tv_sec++;
|
||||
time_tai--;
|
||||
wall_to_monotonic.tv_sec--;
|
||||
time_state = TIME_WAIT;
|
||||
printk(KERN_NOTICE "Clock: "
|
||||
"deleting leap second 23:59:59 UTC\n");
|
||||
break;
|
||||
case TIME_OOP:
|
||||
time_tai++;
|
||||
time_state = TIME_WAIT;
|
||||
/* fall through */
|
||||
case TIME_WAIT:
|
||||
if (!(time_status & (STA_INS | STA_DEL)))
|
||||
time_state = TIME_OK;
|
||||
break;
|
||||
}
|
||||
update_vsyscall(&xtime, clock);
|
||||
|
||||
write_sequnlock_irq(&xtime_lock);
|
||||
|
||||
return res;
|
||||
}
|
||||
|
||||
/*
|
||||
* this routine handles the overflow of the microsecond field
|
||||
*
|
||||
|
@ -138,48 +189,6 @@ void second_overflow(void)
|
|||
time_status |= STA_UNSYNC;
|
||||
}
|
||||
|
||||
/*
|
||||
* Leap second processing. If in leap-insert state at the end of the
|
||||
* day, the system clock is set back one second; if in leap-delete
|
||||
* state, the system clock is set ahead one second. The microtime()
|
||||
* routine or external clock driver will insure that reported time is
|
||||
* always monotonic. The ugly divides should be replaced.
|
||||
*/
|
||||
switch (time_state) {
|
||||
case TIME_OK:
|
||||
if (time_status & STA_INS)
|
||||
time_state = TIME_INS;
|
||||
else if (time_status & STA_DEL)
|
||||
time_state = TIME_DEL;
|
||||
break;
|
||||
case TIME_INS:
|
||||
if (xtime.tv_sec % 86400 == 0) {
|
||||
xtime.tv_sec--;
|
||||
wall_to_monotonic.tv_sec++;
|
||||
time_state = TIME_OOP;
|
||||
printk(KERN_NOTICE "Clock: inserting leap second "
|
||||
"23:59:60 UTC\n");
|
||||
}
|
||||
break;
|
||||
case TIME_DEL:
|
||||
if ((xtime.tv_sec + 1) % 86400 == 0) {
|
||||
xtime.tv_sec++;
|
||||
time_tai--;
|
||||
wall_to_monotonic.tv_sec--;
|
||||
time_state = TIME_WAIT;
|
||||
printk(KERN_NOTICE "Clock: deleting leap second "
|
||||
"23:59:59 UTC\n");
|
||||
}
|
||||
break;
|
||||
case TIME_OOP:
|
||||
time_tai++;
|
||||
time_state = TIME_WAIT;
|
||||
break;
|
||||
case TIME_WAIT:
|
||||
if (!(time_status & (STA_INS | STA_DEL)))
|
||||
time_state = TIME_OK;
|
||||
}
|
||||
|
||||
/*
|
||||
* Compute the phase adjustment for the next second. The offset is
|
||||
* reduced by a fixed factor times the time constant.
|
||||
|
@ -268,7 +277,7 @@ static inline void notify_cmos_timer(void) { }
|
|||
int do_adjtimex(struct timex *txc)
|
||||
{
|
||||
struct timespec ts;
|
||||
long save_adjust;
|
||||
long save_adjust, sec;
|
||||
int result;
|
||||
|
||||
/* In order to modify anything, you gotta be super-user! */
|
||||
|
@ -289,6 +298,10 @@ int do_adjtimex(struct timex *txc)
|
|||
txc->tick > 1100000/USER_HZ)
|
||||
return -EINVAL;
|
||||
|
||||
if (time_state != TIME_OK && txc->modes & ADJ_STATUS)
|
||||
hrtimer_cancel(&leap_timer);
|
||||
getnstimeofday(&ts);
|
||||
|
||||
write_seqlock_irq(&xtime_lock);
|
||||
|
||||
/* Save for later - semantics of adjtime is to return old value */
|
||||
|
@ -305,6 +318,34 @@ int do_adjtimex(struct timex *txc)
|
|||
/* only set allowed bits */
|
||||
time_status &= STA_RONLY;
|
||||
time_status |= txc->status & ~STA_RONLY;
|
||||
|
||||
switch (time_state) {
|
||||
case TIME_OK:
|
||||
start_timer:
|
||||
sec = ts.tv_sec;
|
||||
if (time_status & STA_INS) {
|
||||
time_state = TIME_INS;
|
||||
sec += 86400 - sec % 86400;
|
||||
hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
|
||||
} else if (time_status & STA_DEL) {
|
||||
time_state = TIME_DEL;
|
||||
sec += 86400 - (sec + 1) % 86400;
|
||||
hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
|
||||
}
|
||||
break;
|
||||
case TIME_INS:
|
||||
case TIME_DEL:
|
||||
time_state = TIME_OK;
|
||||
goto start_timer;
|
||||
break;
|
||||
case TIME_WAIT:
|
||||
if (!(time_status & (STA_INS | STA_DEL)))
|
||||
time_state = TIME_OK;
|
||||
break;
|
||||
case TIME_OOP:
|
||||
hrtimer_restart(&leap_timer);
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if (txc->modes & ADJ_NANO)
|
||||
|
@ -384,7 +425,6 @@ int do_adjtimex(struct timex *txc)
|
|||
txc->stbcnt = 0;
|
||||
write_sequnlock_irq(&xtime_lock);
|
||||
|
||||
getnstimeofday(&ts);
|
||||
txc->time.tv_sec = ts.tv_sec;
|
||||
txc->time.tv_usec = ts.tv_nsec;
|
||||
if (!(time_status & STA_NANO))
|
||||
|
@ -402,3 +442,10 @@ static int __init ntp_tick_adj_setup(char *str)
|
|||
}
|
||||
|
||||
__setup("ntp_tick_adj=", ntp_tick_adj_setup);
|
||||
|
||||
void __init ntp_init(void)
|
||||
{
|
||||
ntp_clear();
|
||||
hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
|
||||
leap_timer.function = ntp_leap_second;
|
||||
}
|
||||
|
|
|
@ -53,7 +53,7 @@ void update_xtime_cache(u64 nsec)
|
|||
timespec_add_ns(&xtime_cache, nsec);
|
||||
}
|
||||
|
||||
static struct clocksource *clock; /* pointer to current clocksource */
|
||||
struct clocksource *clock;
|
||||
|
||||
|
||||
#ifdef CONFIG_GENERIC_TIME
|
||||
|
@ -246,7 +246,7 @@ void __init timekeeping_init(void)
|
|||
|
||||
write_seqlock_irqsave(&xtime_lock, flags);
|
||||
|
||||
ntp_clear();
|
||||
ntp_init();
|
||||
|
||||
clock = clocksource_get_next();
|
||||
clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
|
||||
|
|
Loading…
Reference in a new issue