[linux.git] / kernel / time / ntp.c

/*
 * NTP state machine interfaces and logic.
 *
 * This code was mainly moved from kernel/timer.c and kernel/time.c
 * Please see those files for relevant copyright info and historical
 * changelogs.
 */
#include <linux/capability.h>
#include <linux/clocksource.h>
#include <linux/workqueue.h>
#include <linux/hrtimer.h>
#include <linux/jiffies.h>
#include <linux/math64.h>
#include <linux/timex.h>
#include <linux/time.h>
#include <linux/mm.h>

/*
 * NTP timekeeping variables:
 */

/* USER_HZ period (usecs): */
unsigned long			tick_usec = TICK_USEC;

/* ACTHZ period (nsecs): */
unsigned long			tick_nsec;

u64				tick_length;
static u64			tick_length_base;

static struct hrtimer		leap_timer;

#define MAX_TICKADJ		500LL		/* usecs */
#define MAX_TICKADJ_SCALED \
	(((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)

/*
 * phase-lock loop variables
 */

/*
 * clock synchronization status
 *
 * (TIME_ERROR prevents overwriting the CMOS clock)
 */
static int			time_state = TIME_OK;

/* clock status bits:							*/
int				time_status = STA_UNSYNC;

/* TAI offset (secs):							*/
static long			time_tai;

/* time adjustment (nsecs):						*/
static s64			time_offset;

/* pll time constant:							*/
static long			time_constant = 2;

/* maximum error (usecs):						*/
long				time_maxerror = NTP_PHASE_LIMIT;

/* estimated error (usecs):						*/
long				time_esterror = NTP_PHASE_LIMIT;

/* frequency offset (scaled nsecs/secs):				*/
static s64			time_freq;

/* time at last adjustment (secs):					*/
static long			time_reftime;

long				time_adjust;

static long			ntp_tick_adj;

/*
 * NTP methods:
 */

/*
 * Update (tick_length, tick_length_base, tick_nsec), based
 * on (tick_usec, ntp_tick_adj, time_freq):
 */
static void ntp_update_frequency(void)
{
	u64 second_length;
	u64 new_base;

	second_length		 = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
						<< NTP_SCALE_SHIFT;

	second_length		+= (s64)ntp_tick_adj << NTP_SCALE_SHIFT;
	second_length		+= time_freq;

	tick_nsec		 = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
	new_base		 = div_u64(second_length, NTP_INTERVAL_FREQ);

	/*
	 * Don't wait for the next second_overflow, apply
	 * the change to the tick length immediately:
	 */
	tick_length		+= new_base - tick_length_base;
	tick_length_base	 = new_base;
}

static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
{
	time_status &= ~STA_MODE;

	if (secs < MINSEC)
		return 0;

	if (!(time_status & STA_FLL) && (secs <= MAXSEC))
		return 0;

	time_status |= STA_MODE;

	return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
}

static void ntp_update_offset(long offset)
{
	s64 freq_adj;
	s64 offset64;
	long secs;

	if (!(time_status & STA_PLL))
		return;

	if (!(time_status & STA_NANO))
		offset *= NSEC_PER_USEC;

	/*
	 * Scale the phase adjustment and
	 * clamp to the operating range.
	 */
	offset = min(offset, MAXPHASE);
	offset = max(offset, -MAXPHASE);

	/*
	 * Select how the frequency is to be controlled
	 * and in which mode (PLL or FLL).
	 */
	secs = xtime.tv_sec - time_reftime;
	if (unlikely(time_status & STA_FREQHOLD))
		secs = 0;

	time_reftime = xtime.tv_sec;

	offset64    = offset;
	freq_adj    = (offset64 * secs) <<
			(NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));

	freq_adj    += ntp_update_offset_fll(offset64, secs);

	freq_adj    = min(freq_adj + time_freq, MAXFREQ_SCALED);

	time_freq   = max(freq_adj, -MAXFREQ_SCALED);

	time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
}

/**
 * ntp_clear - Clears the NTP state variables
 *
 * Must be called while holding a write on the xtime_lock
 */
void ntp_clear(void)
{
	time_adjust	= 0;		/* stop active adjtime() */
	time_status	|= STA_UNSYNC;
	time_maxerror	= NTP_PHASE_LIMIT;
	time_esterror	= NTP_PHASE_LIMIT;

	ntp_update_frequency();

	tick_length	= tick_length_base;
	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(&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");
		hrtimer_add_expires_ns(&leap_timer, 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(&xtime_lock);

	return res;
}

/*
 * this routine handles the overflow of the microsecond field
 *
 * The tricky bits of code to handle the accurate clock support
 * were provided by Dave Mills ([email protected]) of NTP fame.
 * They were originally developed for SUN and DEC kernels.
 * All the kudos should go to Dave for this stuff.
 */
void second_overflow(void)
{
	s64 time_adj;

	/* Bump the maxerror field */
	time_maxerror += MAXFREQ / NSEC_PER_USEC;
	if (time_maxerror > NTP_PHASE_LIMIT) {
		time_maxerror = NTP_PHASE_LIMIT;
		time_status |= STA_UNSYNC;
	}

	/*
	 * Compute the phase adjustment for the next second. The offset is
	 * reduced by a fixed factor times the time constant.
	 */
	tick_length	= tick_length_base;
	time_adj	= shift_right(time_offset, SHIFT_PLL + time_constant);
	time_offset	-= time_adj;
	tick_length	+= time_adj;

	if (!time_adjust)
		return;

	if (time_adjust > MAX_TICKADJ) {
		time_adjust -= MAX_TICKADJ;
		tick_length += MAX_TICKADJ_SCALED;
		return;
	}

	if (time_adjust < -MAX_TICKADJ) {
		time_adjust += MAX_TICKADJ;
		tick_length -= MAX_TICKADJ_SCALED;
		return;
	}

	tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
							 << NTP_SCALE_SHIFT;
	time_adjust = 0;
}

#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(struct work_struct *work);

static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);

static void sync_cmos_clock(struct work_struct *work)
{
	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(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
		fail = update_persistent_clock(now);

	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
	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;
	}
	schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
}

static void notify_cmos_timer(void)
{
	if (!no_sync_cmos_clock)
		schedule_delayed_work(&sync_cmos_work, 0);
}

#else
static inline void notify_cmos_timer(void) { }
#endif

/*
 * Start the leap seconds timer:
 */
static inline void ntp_start_leap_timer(struct timespec *ts)
{
	long now = ts->tv_sec;

	if (time_status & STA_INS) {
		time_state = TIME_INS;
		now += 86400 - now % 86400;
		hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);

		return;
	}

	if (time_status & STA_DEL) {
		time_state = TIME_DEL;
		now += 86400 - (now + 1) % 86400;
		hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
	}
}

/*
 * Propagate a new txc->status value into the NTP state:
 */
static inline void process_adj_status(struct timex *txc, struct timespec *ts)
{
	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
		time_state = TIME_OK;
		time_status = STA_UNSYNC;
	}
	/* only set allowed bits */
	time_status &= STA_RONLY;

	/*
	 * If we turn on PLL adjustments then reset the
	 * reference time to current time.
	 */
	if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
		time_reftime = xtime.tv_sec;

	time_status |= txc->status & ~STA_RONLY;

	switch (time_state) {
	case TIME_OK:
		ntp_start_leap_timer(ts);
		break;
	case TIME_INS:
	case TIME_DEL:
		time_state = TIME_OK;
		ntp_start_leap_timer(ts);
	case TIME_WAIT:
		if (!(time_status & (STA_INS | STA_DEL)))
			time_state = TIME_OK;
		break;
	case TIME_OOP:
		hrtimer_restart(&leap_timer);
		break;
	}
}
/*
 * Called with the xtime lock held, so we can access and modify
 * all the global NTP state:
 */
static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts)
{
	if (txc->modes & ADJ_STATUS)
		process_adj_status(txc, ts);

	if (txc->modes & ADJ_NANO)
		time_status |= STA_NANO;

	if (txc->modes & ADJ_MICRO)
		time_status &= ~STA_NANO;

	if (txc->modes & ADJ_FREQUENCY) {
		time_freq = txc->freq * PPM_SCALE;
		time_freq = min(time_freq, MAXFREQ_SCALED);
		time_freq = max(time_freq, -MAXFREQ_SCALED);
	}

	if (txc->modes & ADJ_MAXERROR)
		time_maxerror = txc->maxerror;

	if (txc->modes & ADJ_ESTERROR)
		time_esterror = txc->esterror;

	if (txc->modes & ADJ_TIMECONST) {
		time_constant = txc->constant;
		if (!(time_status & STA_NANO))
			time_constant += 4;
		time_constant = min(time_constant, (long)MAXTC);
		time_constant = max(time_constant, 0l);
	}

	if (txc->modes & ADJ_TAI && txc->constant > 0)
		time_tai = txc->constant;

	if (txc->modes & ADJ_OFFSET)
		ntp_update_offset(txc->offset);

	if (txc->modes & ADJ_TICK)
		tick_usec = txc->tick;

	if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
		ntp_update_frequency();
}

/*
 * adjtimex mainly allows reading (and writing, if superuser) of
 * kernel time-keeping variables. used by xntpd.
 */
int do_adjtimex(struct timex *txc)
{
	struct timespec ts;
	int result;

	/* Validate the data before disabling interrupts */
	if (txc->modes & ADJ_ADJTIME) {
		/* singleshot must not be used with any other mode bits */
		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
			return -EINVAL;
		if (!(txc->modes & ADJ_OFFSET_READONLY) &&
		    !capable(CAP_SYS_TIME))
			return -EPERM;
	} else {
		/* In order to modify anything, you gotta be super-user! */
		 if (txc->modes && !capable(CAP_SYS_TIME))
			return -EPERM;

		/*
		 * if the quartz is off by more than 10% then
		 * something is VERY wrong!
		 */
		if (txc->modes & ADJ_TICK &&
		    (txc->tick <  900000/USER_HZ ||
		     txc->tick > 1100000/USER_HZ))
			return -EINVAL;

		if (txc->modes & ADJ_STATUS && time_state != TIME_OK)
			hrtimer_cancel(&leap_timer);
	}

	getnstimeofday(&ts);

	write_seqlock_irq(&xtime_lock);

	if (txc->modes & ADJ_ADJTIME) {
		long save_adjust = time_adjust;

		if (!(txc->modes & ADJ_OFFSET_READONLY)) {
			/* adjtime() is independent from ntp_adjtime() */
			time_adjust = txc->offset;
			ntp_update_frequency();
		}
		txc->offset = save_adjust;
	} else {

		/* If there are input parameters, then process them: */
		if (txc->modes)
			process_adjtimex_modes(txc, &ts);

		txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
				  NTP_SCALE_SHIFT);
		if (!(time_status & STA_NANO))
			txc->offset /= NSEC_PER_USEC;
	}

	result = time_state;	/* mostly `TIME_OK' */
	if (time_status & (STA_UNSYNC|STA_CLOCKERR))
		result = TIME_ERROR;

	txc->freq	   = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
					 PPM_SCALE_INV, NTP_SCALE_SHIFT);
	txc->maxerror	   = time_maxerror;
	txc->esterror	   = time_esterror;
	txc->status	   = time_status;
	txc->constant	   = time_constant;
	txc->precision	   = 1;
	txc->tolerance	   = MAXFREQ_SCALED / PPM_SCALE;
	txc->tick	   = tick_usec;
	txc->tai	   = time_tai;

	/* PPS is not implemented, so these are zero */
	txc->ppsfreq	   = 0;
	txc->jitter	   = 0;
	txc->shift	   = 0;
	txc->stabil	   = 0;
	txc->jitcnt	   = 0;
	txc->calcnt	   = 0;
	txc->errcnt	   = 0;
	txc->stbcnt	   = 0;

	write_sequnlock_irq(&xtime_lock);

	txc->time.tv_sec = ts.tv_sec;
	txc->time.tv_usec = ts.tv_nsec;
	if (!(time_status & STA_NANO))
		txc->time.tv_usec /= NSEC_PER_USEC;

	notify_cmos_timer();

	return result;
}

static int __init ntp_tick_adj_setup(char *str)
{
	ntp_tick_adj = simple_strtol(str, NULL, 0);
	return 1;
}

__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;
}
Commit	Line	Data
4c7ee8de	1	/*
4c7ee8de JS	2	* NTP state machine interfaces and logic.
	3	*
	4	* This code was mainly moved from kernel/timer.c and kernel/time.c
	5	* Please see those files for relevant copyright info and historical
	6	* changelogs.
	7	*/
aa0ac365	8	#include <linux/capability.h>
7dffa3c6	9	#include <linux/clocksource.h>
eb3f938f	10	#include <linux/workqueue.h>
53bbfa9e IM	11	#include <linux/hrtimer.h>
	12	#include <linux/jiffies.h>
	13	#include <linux/math64.h>
	14	#include <linux/timex.h>
	15	#include <linux/time.h>
	16	#include <linux/mm.h>
4c7ee8de	17
b0ee7556	18	/*
53bbfa9e	19	* NTP timekeeping variables:
b0ee7556	20	*/
b0ee7556	21
53bbfa9e IM	22	/* USER_HZ period (usecs): */
	23	unsigned long tick_usec = TICK_USEC;
	24
	25	/* ACTHZ period (nsecs): */
	26	unsigned long tick_nsec;
7dffa3c6	27
53bbfa9e IM	28	u64 tick_length;
	29	static u64 tick_length_base;
	30
	31	static struct hrtimer leap_timer;
	32
bbd12676	33	#define MAX_TICKADJ 500LL /* usecs */
53bbfa9e	34	#define MAX_TICKADJ_SCALED \
bbd12676	35	(((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
4c7ee8de JS	36
	37	/*
	38	* phase-lock loop variables
	39	*/
53bbfa9e IM	40
	41	/*
	42	* clock synchronization status
	43	*
	44	* (TIME_ERROR prevents overwriting the CMOS clock)
	45	*/
	46	static int time_state = TIME_OK;
	47
	48	/* clock status bits: */
	49	int time_status = STA_UNSYNC;
	50
	51	/* TAI offset (secs): */
	52	static long time_tai;
	53
	54	/* time adjustment (nsecs): */
	55	static s64 time_offset;
	56
	57	/* pll time constant: */
	58	static long time_constant = 2;
	59
	60	/* maximum error (usecs): */
	61	long time_maxerror = NTP_PHASE_LIMIT;
	62
	63	/* estimated error (usecs): */
	64	long time_esterror = NTP_PHASE_LIMIT;
	65
	66	/* frequency offset (scaled nsecs/secs): */
	67	static s64 time_freq;
	68
	69	/* time at last adjustment (secs): */
	70	static long time_reftime;
	71
	72	long time_adjust;
	73
	74	static long ntp_tick_adj;
	75
	76	/*
	77	* NTP methods:
	78	*/
4c7ee8de	79
9ce616aa IM	80	/*
	81	* Update (tick_length, tick_length_base, tick_nsec), based
	82	* on (tick_usec, ntp_tick_adj, time_freq):
	83	*/
70bc42f9 AB	84	static void ntp_update_frequency(void)
70bc42f9 AB	85	{
9ce616aa	86	u64 second_length;
bc26c31d	87	u64 new_base;
9ce616aa IM	88
	89	second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
	90	<< NTP_SCALE_SHIFT;
	91
	92	second_length += (s64)ntp_tick_adj << NTP_SCALE_SHIFT;
	93	second_length += time_freq;
70bc42f9	94
9ce616aa	95	tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
bc26c31d	96	new_base = div_u64(second_length, NTP_INTERVAL_FREQ);
fdcedf7b JS	97
	98	/*
	99	* Don't wait for the next second_overflow, apply
bc26c31d	100	* the change to the tick length immediately:
fdcedf7b	101	*/
bc26c31d IM	102	tick_length += new_base - tick_length_base;
bc26c31d IM	103	tick_length_base = new_base;
70bc42f9 AB	104	}
70bc42f9 AB	105
478b7aab	106	static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
f939890b IM	107	{
	108	time_status &= ~STA_MODE;
	109
	110	if (secs < MINSEC)
478b7aab	111	return 0;
f939890b IM	112
f939890b IM	113	if (!(time_status & STA_FLL) && (secs <= MAXSEC))
478b7aab	114	return 0;
f939890b	115
f939890b IM	116	time_status \|= STA_MODE;
f939890b IM	117
478b7aab	118	return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
f939890b IM	119	}
f939890b IM	120
ee9851b2 RZ	121	static void ntp_update_offset(long offset)
ee9851b2 RZ	122	{
ee9851b2	123	s64 freq_adj;
f939890b IM	124	s64 offset64;
f939890b IM	125	long secs;
ee9851b2 RZ	126
	127	if (!(time_status & STA_PLL))
	128	return;
	129
eea83d89	130	if (!(time_status & STA_NANO))
9f14f669	131	offset *= NSEC_PER_USEC;
ee9851b2 RZ	132
	133	/*
	134	* Scale the phase adjustment and
	135	* clamp to the operating range.
	136	*/
9f14f669 RZ	137	offset = min(offset, MAXPHASE);
9f14f669 RZ	138	offset = max(offset, -MAXPHASE);
ee9851b2 RZ	139
	140	/*
	141	* Select how the frequency is to be controlled
	142	* and in which mode (PLL or FLL).
	143	*/
f939890b	144	secs = xtime.tv_sec - time_reftime;
10dd31a7	145	if (unlikely(time_status & STA_FREQHOLD))
c7986acb IM	146	secs = 0;
c7986acb IM	147
ee9851b2 RZ	148	time_reftime = xtime.tv_sec;
ee9851b2 RZ	149
f939890b IM	150	offset64 = offset;
	151	freq_adj = (offset64 * secs) <<
	152	(NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
	153
478b7aab	154	freq_adj += ntp_update_offset_fll(offset64, secs);
f939890b IM	155
	156	freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED);
	157
	158	time_freq = max(freq_adj, -MAXFREQ_SCALED);
	159
	160	time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
ee9851b2 RZ	161	}
ee9851b2 RZ	162
b0ee7556 RZ	163	/**
	164	* ntp_clear - Clears the NTP state variables
	165	*
	166	* Must be called while holding a write on the xtime_lock
	167	*/
	168	void ntp_clear(void)
	169	{
53bbfa9e IM	170	time_adjust = 0; /* stop active adjtime() */
	171	time_status \|= STA_UNSYNC;
	172	time_maxerror = NTP_PHASE_LIMIT;
	173	time_esterror = NTP_PHASE_LIMIT;
b0ee7556 RZ	174
	175	ntp_update_frequency();
	176
53bbfa9e IM	177	tick_length = tick_length_base;
53bbfa9e IM	178	time_offset = 0;
b0ee7556 RZ	179	}
b0ee7556 RZ	180
4c7ee8de	181	/*
7dffa3c6 RZ	182	* Leap second processing. If in leap-insert state at the end of the
	183	* day, the system clock is set back one second; if in leap-delete
	184	* state, the system clock is set ahead one second.
4c7ee8de	185	*/
7dffa3c6	186	static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
4c7ee8de	187	{
7dffa3c6	188	enum hrtimer_restart res = HRTIMER_NORESTART;
4c7ee8de	189
ca109491	190	write_seqlock(&xtime_lock);
4c7ee8de	191
4c7ee8de JS	192	switch (time_state) {
4c7ee8de JS	193	case TIME_OK:
4c7ee8de JS	194	break;
4c7ee8de JS	195	case TIME_INS:
7dffa3c6 RZ	196	xtime.tv_sec--;
	197	wall_to_monotonic.tv_sec++;
	198	time_state = TIME_OOP;
53bbfa9e IM	199	printk(KERN_NOTICE
53bbfa9e IM	200	"Clock: inserting leap second 23:59:60 UTC\n");
cc584b21	201	hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
7dffa3c6	202	res = HRTIMER_RESTART;
4c7ee8de JS	203	break;
4c7ee8de JS	204	case TIME_DEL:
7dffa3c6 RZ	205	xtime.tv_sec++;
	206	time_tai--;
	207	wall_to_monotonic.tv_sec--;
	208	time_state = TIME_WAIT;
53bbfa9e IM	209	printk(KERN_NOTICE
53bbfa9e IM	210	"Clock: deleting leap second 23:59:59 UTC\n");
4c7ee8de JS	211	break;
4c7ee8de JS	212	case TIME_OOP:
153b5d05	213	time_tai++;
4c7ee8de	214	time_state = TIME_WAIT;
7dffa3c6	215	/* fall through */
4c7ee8de JS	216	case TIME_WAIT:
4c7ee8de JS	217	if (!(time_status & (STA_INS \| STA_DEL)))
ee9851b2	218	time_state = TIME_OK;
7dffa3c6 RZ	219	break;
	220	}
	221	update_vsyscall(&xtime, clock);
	222
ca109491	223	write_sequnlock(&xtime_lock);
7dffa3c6 RZ	224
	225	return res;
	226	}
	227
	228	/*
	229	* this routine handles the overflow of the microsecond field
	230	*
	231	* The tricky bits of code to handle the accurate clock support
	232	* were provided by Dave Mills ([email protected]) of NTP fame.
	233	* They were originally developed for SUN and DEC kernels.
	234	* All the kudos should go to Dave for this stuff.
	235	*/
	236	void second_overflow(void)
	237	{
	238	s64 time_adj;
	239
	240	/* Bump the maxerror field */
	241	time_maxerror += MAXFREQ / NSEC_PER_USEC;
	242	if (time_maxerror > NTP_PHASE_LIMIT) {
	243	time_maxerror = NTP_PHASE_LIMIT;
	244	time_status \|= STA_UNSYNC;
4c7ee8de JS	245	}
	246
	247	/*
f1992393 RZ	248	* Compute the phase adjustment for the next second. The offset is
f1992393 RZ	249	* reduced by a fixed factor times the time constant.
4c7ee8de	250	*/
53bbfa9e IM	251	tick_length = tick_length_base;
	252	time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
	253	time_offset -= time_adj;
	254	tick_length += time_adj;
4c7ee8de	255
3c972c24 IM	256	if (!time_adjust)
	257	return;
	258
	259	if (time_adjust > MAX_TICKADJ) {
	260	time_adjust -= MAX_TICKADJ;
	261	tick_length += MAX_TICKADJ_SCALED;
	262	return;
4c7ee8de	263	}
3c972c24 IM	264
	265	if (time_adjust < -MAX_TICKADJ) {
	266	time_adjust += MAX_TICKADJ;
	267	tick_length -= MAX_TICKADJ_SCALED;
	268	return;
	269	}
	270
	271	tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
	272	<< NTP_SCALE_SHIFT;
	273	time_adjust = 0;
4c7ee8de JS	274	}
4c7ee8de JS	275
82644459	276	#ifdef CONFIG_GENERIC_CMOS_UPDATE
4c7ee8de	277
82644459 TG	278	/* Disable the cmos update - used by virtualization and embedded */
	279	int no_sync_cmos_clock __read_mostly;
	280
eb3f938f	281	static void sync_cmos_clock(struct work_struct *work);
82644459	282
eb3f938f	283	static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
82644459	284
eb3f938f	285	static void sync_cmos_clock(struct work_struct *work)
82644459 TG	286	{
	287	struct timespec now, next;
	288	int fail = 1;
	289
	290	/*
	291	* If we have an externally synchronized Linux clock, then update
	292	* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	293	* called as close as possible to 500 ms before the new second starts.
	294	* This code is run on a timer. If the clock is set, that timer
	295	* may not expire at the correct time. Thus, we adjust...
	296	*/
53bbfa9e	297	if (!ntp_synced()) {
82644459 TG	298	/*
	299	* Not synced, exit, do not restart a timer (if one is
	300	* running, let it run out).
	301	*/
	302	return;
53bbfa9e	303	}
82644459 TG	304
82644459 TG	305	getnstimeofday(&now);
fa6a1a55	306	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
82644459 TG	307	fail = update_persistent_clock(now);
82644459 TG	308
4ff4b9e1	309	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
82644459 TG	310	if (next.tv_nsec <= 0)
	311	next.tv_nsec += NSEC_PER_SEC;
	312
	313	if (!fail)
	314	next.tv_sec = 659;
	315	else
	316	next.tv_sec = 0;
	317
	318	if (next.tv_nsec >= NSEC_PER_SEC) {
	319	next.tv_sec++;
	320	next.tv_nsec -= NSEC_PER_SEC;
	321	}
eb3f938f	322	schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
82644459 TG	323	}
	324
	325	static void notify_cmos_timer(void)
4c7ee8de	326	{
298a5df4	327	if (!no_sync_cmos_clock)
eb3f938f	328	schedule_delayed_work(&sync_cmos_work, 0);
4c7ee8de JS	329	}
4c7ee8de JS	330
82644459 TG	331	#else
	332	static inline void notify_cmos_timer(void) { }
	333	#endif
	334
e9629165 IM	335	/*
	336	* Start the leap seconds timer:
	337	*/
	338	static inline void ntp_start_leap_timer(struct timespec *ts)
	339	{
	340	long now = ts->tv_sec;
	341
	342	if (time_status & STA_INS) {
	343	time_state = TIME_INS;
	344	now += 86400 - now % 86400;
	345	hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
	346
	347	return;
	348	}
	349
	350	if (time_status & STA_DEL) {
	351	time_state = TIME_DEL;
	352	now += 86400 - (now + 1) % 86400;
	353	hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
	354	}
	355	}
80f22571 IM	356
	357	/*
	358	* Propagate a new txc->status value into the NTP state:
	359	*/
	360	static inline void process_adj_status(struct timex txc, struct timespec ts)
	361	{
80f22571 IM	362	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
	363	time_state = TIME_OK;
	364	time_status = STA_UNSYNC;
	365	}
	366	/* only set allowed bits */
	367	time_status &= STA_RONLY;
	368
	369	/*
	370	* If we turn on PLL adjustments then reset the
	371	* reference time to current time.
	372	*/
	373	if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
	374	time_reftime = xtime.tv_sec;
	375
	376	time_status \|= txc->status & ~STA_RONLY;
	377
	378	switch (time_state) {
	379	case TIME_OK:
e9629165	380	ntp_start_leap_timer(ts);
80f22571 IM	381	break;
	382	case TIME_INS:
	383	case TIME_DEL:
	384	time_state = TIME_OK;
e9629165	385	ntp_start_leap_timer(ts);
80f22571 IM	386	case TIME_WAIT:
	387	if (!(time_status & (STA_INS \| STA_DEL)))
	388	time_state = TIME_OK;
	389	break;
	390	case TIME_OOP:
	391	hrtimer_restart(&leap_timer);
	392	break;
	393	}
	394	}
	395	/*
	396	* Called with the xtime lock held, so we can access and modify
	397	* all the global NTP state:
	398	*/
	399	static inline void process_adjtimex_modes(struct timex txc, struct timespec ts)
	400	{
	401	if (txc->modes & ADJ_STATUS)
	402	process_adj_status(txc, ts);
	403
	404	if (txc->modes & ADJ_NANO)
	405	time_status \|= STA_NANO;
e9629165	406
80f22571 IM	407	if (txc->modes & ADJ_MICRO)
	408	time_status &= ~STA_NANO;
	409
	410	if (txc->modes & ADJ_FREQUENCY) {
2b9d1496	411	time_freq = txc->freq * PPM_SCALE;
80f22571 IM	412	time_freq = min(time_freq, MAXFREQ_SCALED);
	413	time_freq = max(time_freq, -MAXFREQ_SCALED);
	414	}
	415
	416	if (txc->modes & ADJ_MAXERROR)
	417	time_maxerror = txc->maxerror;
e9629165	418
80f22571 IM	419	if (txc->modes & ADJ_ESTERROR)
	420	time_esterror = txc->esterror;
	421
	422	if (txc->modes & ADJ_TIMECONST) {
	423	time_constant = txc->constant;
	424	if (!(time_status & STA_NANO))
	425	time_constant += 4;
	426	time_constant = min(time_constant, (long)MAXTC);
	427	time_constant = max(time_constant, 0l);
	428	}
	429
	430	if (txc->modes & ADJ_TAI && txc->constant > 0)
	431	time_tai = txc->constant;
	432
	433	if (txc->modes & ADJ_OFFSET)
	434	ntp_update_offset(txc->offset);
e9629165	435
80f22571 IM	436	if (txc->modes & ADJ_TICK)
	437	tick_usec = txc->tick;
	438
	439	if (txc->modes & (ADJ_TICK\|ADJ_FREQUENCY\|ADJ_OFFSET))
	440	ntp_update_frequency();
	441	}
	442
53bbfa9e IM	443	/*
53bbfa9e IM	444	* adjtimex mainly allows reading (and writing, if superuser) of
4c7ee8de JS	445	* kernel time-keeping variables. used by xntpd.
	446	*/
	447	int do_adjtimex(struct timex *txc)
	448	{
eea83d89	449	struct timespec ts;
4c7ee8de JS	450	int result;
4c7ee8de JS	451
916c7a85 RZ	452	/* Validate the data before disabling interrupts */
916c7a85 RZ	453	if (txc->modes & ADJ_ADJTIME) {
eea83d89	454	/* singleshot must not be used with any other mode bits */
916c7a85	455	if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
4c7ee8de	456	return -EINVAL;
916c7a85 RZ	457	if (!(txc->modes & ADJ_OFFSET_READONLY) &&
	458	!capable(CAP_SYS_TIME))
	459	return -EPERM;
	460	} else {
	461	/* In order to modify anything, you gotta be super-user! */
	462	if (txc->modes && !capable(CAP_SYS_TIME))
	463	return -EPERM;
	464
53bbfa9e IM	465	/*
	466	* if the quartz is off by more than 10% then
	467	* something is VERY wrong!
	468	*/
916c7a85 RZ	469	if (txc->modes & ADJ_TICK &&
	470	(txc->tick < 900000/USER_HZ \|\|
	471	txc->tick > 1100000/USER_HZ))
e9629165	472	return -EINVAL;
916c7a85 RZ	473
	474	if (txc->modes & ADJ_STATUS && time_state != TIME_OK)
	475	hrtimer_cancel(&leap_timer);
52bfb360	476	}
4c7ee8de	477
7dffa3c6 RZ	478	getnstimeofday(&ts);
7dffa3c6 RZ	479
4c7ee8de	480	write_seqlock_irq(&xtime_lock);
4c7ee8de	481
916c7a85 RZ	482	if (txc->modes & ADJ_ADJTIME) {
	483	long save_adjust = time_adjust;
	484
	485	if (!(txc->modes & ADJ_OFFSET_READONLY)) {
	486	/* adjtime() is independent from ntp_adjtime() */
	487	time_adjust = txc->offset;
	488	ntp_update_frequency();
	489	}
	490	txc->offset = save_adjust;
e9629165	491	} else {
ee9851b2	492
e9629165 IM	493	/* If there are input parameters, then process them: */
	494	if (txc->modes)
	495	process_adjtimex_modes(txc, &ts);
eea83d89	496
e9629165	497	txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
916c7a85	498	NTP_SCALE_SHIFT);
e9629165 IM	499	if (!(time_status & STA_NANO))
	500	txc->offset /= NSEC_PER_USEC;
	501	}
916c7a85	502
eea83d89	503	result = time_state; /* mostly `TIME_OK' */
ee9851b2	504	if (time_status & (STA_UNSYNC\|STA_CLOCKERR))
4c7ee8de JS	505	result = TIME_ERROR;
4c7ee8de JS	506
d40e944c	507	txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
2b9d1496	508	PPM_SCALE_INV, NTP_SCALE_SHIFT);
4c7ee8de JS	509	txc->maxerror = time_maxerror;
	510	txc->esterror = time_esterror;
	511	txc->status = time_status;
	512	txc->constant = time_constant;
70bc42f9	513	txc->precision = 1;
074b3b87	514	txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
4c7ee8de	515	txc->tick = tick_usec;
153b5d05	516	txc->tai = time_tai;
4c7ee8de JS	517
	518	/* PPS is not implemented, so these are zero */
	519	txc->ppsfreq = 0;
	520	txc->jitter = 0;
	521	txc->shift = 0;
	522	txc->stabil = 0;
	523	txc->jitcnt = 0;
	524	txc->calcnt = 0;
	525	txc->errcnt = 0;
	526	txc->stbcnt = 0;
e9629165	527
4c7ee8de	528	write_sequnlock_irq(&xtime_lock);
ee9851b2	529
eea83d89 RZ	530	txc->time.tv_sec = ts.tv_sec;
	531	txc->time.tv_usec = ts.tv_nsec;
	532	if (!(time_status & STA_NANO))
	533	txc->time.tv_usec /= NSEC_PER_USEC;
ee9851b2	534
82644459	535	notify_cmos_timer();
ee9851b2 RZ	536
ee9851b2 RZ	537	return result;
4c7ee8de	538	}
10a398d0 RZ	539
	540	static int __init ntp_tick_adj_setup(char *str)
	541	{
	542	ntp_tick_adj = simple_strtol(str, NULL, 0);
	543	return 1;
	544	}
	545
	546	__setup("ntp_tick_adj=", ntp_tick_adj_setup);
7dffa3c6 RZ	547
	548	void __init ntp_init(void)
	549	{
	550	ntp_clear();
	551	hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
	552	leap_timer.function = ntp_leap_second;
	553	}