diff options
Diffstat (limited to 'kernel/time/ntp.c')
| -rw-r--r-- | kernel/time/ntp.c | 71 |
1 files changed, 57 insertions, 14 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index cf53bb5814c..cd91237dbfe 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -10,10 +10,11 @@ #include <linux/mm.h> #include <linux/time.h> +#include <linux/timer.h> #include <linux/timex.h> #include <linux/jiffies.h> #include <linux/hrtimer.h> - +#include <linux/capability.h> #include <asm/div64.h> #include <asm/timex.h> @@ -116,11 +117,6 @@ void second_overflow(void) if (xtime.tv_sec % 86400 == 0) { xtime.tv_sec--; wall_to_monotonic.tv_sec++; - /* - * The timer interpolator will make time change - * gradually instead of an immediate jump by one second - */ - time_interpolator_update(-NSEC_PER_SEC); time_state = TIME_OOP; printk(KERN_NOTICE "Clock: inserting leap second " "23:59:60 UTC\n"); @@ -130,11 +126,6 @@ void second_overflow(void) if ((xtime.tv_sec + 1) % 86400 == 0) { xtime.tv_sec++; wall_to_monotonic.tv_sec--; - /* - * Use of time interpolator for a gradual change of - * time - */ - time_interpolator_update(NSEC_PER_SEC); time_state = TIME_WAIT; printk(KERN_NOTICE "Clock: deleting leap second " "23:59:59 UTC\n"); @@ -185,12 +176,64 @@ u64 current_tick_length(void) return tick_length; } +#ifdef CONFIG_GENERIC_CMOS_UPDATE + +/* Disable the cmos update - used by virtualization and embedded */ +int no_sync_cmos_clock __read_mostly; + +static void sync_cmos_clock(unsigned long dummy); + +static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0); -void __attribute__ ((weak)) notify_arch_cmos_timer(void) +static void sync_cmos_clock(unsigned long dummy) { - return; + struct timespec now, next; + int fail = 1; + + /* + * If we have an externally synchronized Linux clock, then update + * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be + * called as close as possible to 500 ms before the new second starts. + * This code is run on a timer. If the clock is set, that timer + * may not expire at the correct time. Thus, we adjust... + */ + if (!ntp_synced()) + /* + * Not synced, exit, do not restart a timer (if one is + * running, let it run out). + */ + return; + + getnstimeofday(&now); + if (abs(xtime.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2) + fail = update_persistent_clock(now); + + next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec; + if (next.tv_nsec <= 0) + next.tv_nsec += NSEC_PER_SEC; + + if (!fail) + next.tv_sec = 659; + else + next.tv_sec = 0; + + if (next.tv_nsec >= NSEC_PER_SEC) { + next.tv_sec++; + next.tv_nsec -= NSEC_PER_SEC; + } + mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next)); } +static void notify_cmos_timer(void) +{ + if (no_sync_cmos_clock) + mod_timer(&sync_cmos_timer, jiffies + 1); +} + +#else +static inline void notify_cmos_timer(void) { } +#endif + /* adjtimex mainly allows reading (and writing, if superuser) of * kernel time-keeping variables. used by xntpd. */ @@ -355,6 +398,6 @@ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0) txc->stbcnt = 0; write_sequnlock_irq(&xtime_lock); do_gettimeofday(&txc->time); - notify_arch_cmos_timer(); + notify_cmos_timer(); return(result); } |