[net-next-2.6.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):						*/
static long			time_maxerror = NTP_PHASE_LIMIT;

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

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

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

static long			time_adjust;

/* constant (boot-param configurable) NTP tick adjustment (upscaled)	*/
static s64			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		+= ntp_tick_adj;
	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 = get_seconds() - time_reftime;
	if (unlikely(time_status & STA_FREQHOLD))
		secs = 0;

	time_reftime = get_seconds();

	offset64    = offset;
	freq_adj    = ntp_update_offset_fll(offset64, secs);

	/*
	 * Clamp update interval to reduce PLL gain with low
	 * sampling rate (e.g. intermittent network connection)
	 * to avoid instability.
	 */
	if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
		secs = 1 << (SHIFT_PLL + 1 + time_constant);

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

	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:
		timekeeping_leap_insert(-1);
		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:
		timekeeping_leap_insert(1);
		time_tai--;
		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;
	}

	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 (Mills@UDEL.EDU) 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 delta;

	/* 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;

	delta		 = shift_right(time_offset, SHIFT_PLL + time_constant);
	time_offset	-= delta;
	tick_length	+= delta;

	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;
	}

	/*
	 * 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 = get_seconds();

	/* only set allowed bits */
	time_status &= STA_RONLY;
	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);
	ntp_tick_adj <<= NTP_SCALE_SHIFT;

	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): */
1f5b8f8a	61	static long time_maxerror = NTP_PHASE_LIMIT;
53bbfa9e IM	62
53bbfa9e IM	63	/* estimated error (usecs): */
1f5b8f8a	64	static long time_esterror = NTP_PHASE_LIMIT;
53bbfa9e IM	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
e1292ba1	72	static long time_adjust;
53bbfa9e	73
069569e0 IM	74	/* constant (boot-param configurable) NTP tick adjustment (upscaled) */
069569e0 IM	75	static s64 ntp_tick_adj;
53bbfa9e IM	76
	77	/*
	78	* NTP methods:
	79	*/
4c7ee8de	80
9ce616aa IM	81	/*
	82	* Update (tick_length, tick_length_base, tick_nsec), based
	83	* on (tick_usec, ntp_tick_adj, time_freq):
	84	*/
70bc42f9 AB	85	static void ntp_update_frequency(void)
70bc42f9 AB	86	{
9ce616aa	87	u64 second_length;
bc26c31d	88	u64 new_base;
9ce616aa IM	89
	90	second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
	91	<< NTP_SCALE_SHIFT;
	92
069569e0	93	second_length += ntp_tick_adj;
9ce616aa	94	second_length += time_freq;
70bc42f9	95
9ce616aa	96	tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
bc26c31d	97	new_base = div_u64(second_length, NTP_INTERVAL_FREQ);
fdcedf7b JS	98
	99	/*
	100	* Don't wait for the next second_overflow, apply
bc26c31d	101	* the change to the tick length immediately:
fdcedf7b	102	*/
bc26c31d IM	103	tick_length += new_base - tick_length_base;
bc26c31d IM	104	tick_length_base = new_base;
70bc42f9 AB	105	}
70bc42f9 AB	106
478b7aab	107	static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
f939890b IM	108	{
	109	time_status &= ~STA_MODE;
	110
	111	if (secs < MINSEC)
478b7aab	112	return 0;
f939890b IM	113
f939890b IM	114	if (!(time_status & STA_FLL) && (secs <= MAXSEC))
478b7aab	115	return 0;
f939890b	116
f939890b IM	117	time_status \|= STA_MODE;
f939890b IM	118
478b7aab	119	return div_s64(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
f939890b IM	120	}
f939890b IM	121
ee9851b2 RZ	122	static void ntp_update_offset(long offset)
ee9851b2 RZ	123	{
ee9851b2	124	s64 freq_adj;
f939890b IM	125	s64 offset64;
f939890b IM	126	long secs;
ee9851b2 RZ	127
	128	if (!(time_status & STA_PLL))
	129	return;
	130
eea83d89	131	if (!(time_status & STA_NANO))
9f14f669	132	offset *= NSEC_PER_USEC;
ee9851b2 RZ	133
	134	/*
	135	* Scale the phase adjustment and
	136	* clamp to the operating range.
	137	*/
9f14f669 RZ	138	offset = min(offset, MAXPHASE);
9f14f669 RZ	139	offset = max(offset, -MAXPHASE);
ee9851b2 RZ	140
	141	/*
	142	* Select how the frequency is to be controlled
	143	* and in which mode (PLL or FLL).
	144	*/
7e1b5847	145	secs = get_seconds() - time_reftime;
10dd31a7	146	if (unlikely(time_status & STA_FREQHOLD))
c7986acb IM	147	secs = 0;
c7986acb IM	148
7e1b5847	149	time_reftime = get_seconds();
ee9851b2	150
f939890b	151	offset64 = offset;
8af3c153	152	freq_adj = ntp_update_offset_fll(offset64, secs);
f939890b	153
8af3c153 ML	154	/*
	155	* Clamp update interval to reduce PLL gain with low
	156	* sampling rate (e.g. intermittent network connection)
	157	* to avoid instability.
	158	*/
	159	if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
	160	secs = 1 << (SHIFT_PLL + 1 + time_constant);
	161
	162	freq_adj += (offset64 * secs) <<
	163	(NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
f939890b IM	164
	165	freq_adj = min(freq_adj + time_freq, MAXFREQ_SCALED);
	166
	167	time_freq = max(freq_adj, -MAXFREQ_SCALED);
	168
	169	time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
ee9851b2 RZ	170	}
ee9851b2 RZ	171
b0ee7556 RZ	172	/**
	173	* ntp_clear - Clears the NTP state variables
	174	*
	175	* Must be called while holding a write on the xtime_lock
	176	*/
	177	void ntp_clear(void)
	178	{
53bbfa9e IM	179	time_adjust = 0; /* stop active adjtime() */
	180	time_status \|= STA_UNSYNC;
	181	time_maxerror = NTP_PHASE_LIMIT;
	182	time_esterror = NTP_PHASE_LIMIT;
b0ee7556 RZ	183
	184	ntp_update_frequency();
	185
53bbfa9e IM	186	tick_length = tick_length_base;
53bbfa9e IM	187	time_offset = 0;
b0ee7556 RZ	188	}
b0ee7556 RZ	189
4c7ee8de	190	/*
7dffa3c6 RZ	191	* Leap second processing. If in leap-insert state at the end of the
	192	* day, the system clock is set back one second; if in leap-delete
	193	* state, the system clock is set ahead one second.
4c7ee8de	194	*/
7dffa3c6	195	static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
4c7ee8de	196	{
7dffa3c6	197	enum hrtimer_restart res = HRTIMER_NORESTART;
4c7ee8de	198
ca109491	199	write_seqlock(&xtime_lock);
4c7ee8de	200
4c7ee8de JS	201	switch (time_state) {
4c7ee8de JS	202	case TIME_OK:
4c7ee8de JS	203	break;
4c7ee8de JS	204	case TIME_INS:
31089c13	205	timekeeping_leap_insert(-1);
7dffa3c6	206	time_state = TIME_OOP;
53bbfa9e IM	207	printk(KERN_NOTICE
53bbfa9e IM	208	"Clock: inserting leap second 23:59:60 UTC\n");
cc584b21	209	hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
7dffa3c6	210	res = HRTIMER_RESTART;
4c7ee8de JS	211	break;
4c7ee8de JS	212	case TIME_DEL:
31089c13	213	timekeeping_leap_insert(1);
7dffa3c6	214	time_tai--;
7dffa3c6	215	time_state = TIME_WAIT;
53bbfa9e IM	216	printk(KERN_NOTICE
53bbfa9e IM	217	"Clock: deleting leap second 23:59:59 UTC\n");
4c7ee8de JS	218	break;
4c7ee8de JS	219	case TIME_OOP:
153b5d05	220	time_tai++;
4c7ee8de	221	time_state = TIME_WAIT;
7dffa3c6	222	/* fall through */
4c7ee8de JS	223	case TIME_WAIT:
4c7ee8de JS	224	if (!(time_status & (STA_INS \| STA_DEL)))
ee9851b2	225	time_state = TIME_OK;
7dffa3c6 RZ	226	break;
7dffa3c6 RZ	227	}
7dffa3c6	228
ca109491	229	write_sequnlock(&xtime_lock);
7dffa3c6 RZ	230
	231	return res;
	232	}
	233
	234	/*
	235	* this routine handles the overflow of the microsecond field
	236	*
	237	* The tricky bits of code to handle the accurate clock support
	238	* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
	239	* They were originally developed for SUN and DEC kernels.
	240	* All the kudos should go to Dave for this stuff.
	241	*/
	242	void second_overflow(void)
	243	{
39854fe8	244	s64 delta;
7dffa3c6 RZ	245
	246	/* Bump the maxerror field */
	247	time_maxerror += MAXFREQ / NSEC_PER_USEC;
	248	if (time_maxerror > NTP_PHASE_LIMIT) {
	249	time_maxerror = NTP_PHASE_LIMIT;
	250	time_status \|= STA_UNSYNC;
4c7ee8de JS	251	}
	252
	253	/*
f1992393 RZ	254	* Compute the phase adjustment for the next second. The offset is
f1992393 RZ	255	* reduced by a fixed factor times the time constant.
4c7ee8de	256	*/
39854fe8 IM	257	tick_length = tick_length_base;
	258
	259	delta = shift_right(time_offset, SHIFT_PLL + time_constant);
	260	time_offset -= delta;
	261	tick_length += delta;
4c7ee8de	262
3c972c24 IM	263	if (!time_adjust)
	264	return;
	265
	266	if (time_adjust > MAX_TICKADJ) {
	267	time_adjust -= MAX_TICKADJ;
	268	tick_length += MAX_TICKADJ_SCALED;
	269	return;
4c7ee8de	270	}
3c972c24 IM	271
	272	if (time_adjust < -MAX_TICKADJ) {
	273	time_adjust += MAX_TICKADJ;
	274	tick_length -= MAX_TICKADJ_SCALED;
	275	return;
	276	}
	277
	278	tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
	279	<< NTP_SCALE_SHIFT;
	280	time_adjust = 0;
4c7ee8de JS	281	}
4c7ee8de JS	282
82644459	283	#ifdef CONFIG_GENERIC_CMOS_UPDATE
4c7ee8de	284
82644459 TG	285	/* Disable the cmos update - used by virtualization and embedded */
	286	int no_sync_cmos_clock __read_mostly;
	287
eb3f938f	288	static void sync_cmos_clock(struct work_struct *work);
82644459	289
eb3f938f	290	static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
82644459	291
eb3f938f	292	static void sync_cmos_clock(struct work_struct *work)
82644459 TG	293	{
	294	struct timespec now, next;
	295	int fail = 1;
	296
	297	/*
	298	* If we have an externally synchronized Linux clock, then update
	299	* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	300	* called as close as possible to 500 ms before the new second starts.
	301	* This code is run on a timer. If the clock is set, that timer
	302	* may not expire at the correct time. Thus, we adjust...
	303	*/
53bbfa9e	304	if (!ntp_synced()) {
82644459 TG	305	/*
	306	* Not synced, exit, do not restart a timer (if one is
	307	* running, let it run out).
	308	*/
	309	return;
53bbfa9e	310	}
82644459 TG	311
82644459 TG	312	getnstimeofday(&now);
fa6a1a55	313	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
82644459 TG	314	fail = update_persistent_clock(now);
82644459 TG	315
4ff4b9e1	316	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
82644459 TG	317	if (next.tv_nsec <= 0)
	318	next.tv_nsec += NSEC_PER_SEC;
	319
	320	if (!fail)
	321	next.tv_sec = 659;
	322	else
	323	next.tv_sec = 0;
	324
	325	if (next.tv_nsec >= NSEC_PER_SEC) {
	326	next.tv_sec++;
	327	next.tv_nsec -= NSEC_PER_SEC;
	328	}
eb3f938f	329	schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
82644459 TG	330	}
	331
	332	static void notify_cmos_timer(void)
4c7ee8de	333	{
298a5df4	334	if (!no_sync_cmos_clock)
eb3f938f	335	schedule_delayed_work(&sync_cmos_work, 0);
4c7ee8de JS	336	}
4c7ee8de JS	337
82644459 TG	338	#else
	339	static inline void notify_cmos_timer(void) { }
	340	#endif
	341
e9629165 IM	342	/*
	343	* Start the leap seconds timer:
	344	*/
	345	static inline void ntp_start_leap_timer(struct timespec *ts)
	346	{
	347	long now = ts->tv_sec;
	348
	349	if (time_status & STA_INS) {
	350	time_state = TIME_INS;
	351	now += 86400 - now % 86400;
	352	hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
	353
	354	return;
	355	}
	356
	357	if (time_status & STA_DEL) {
	358	time_state = TIME_DEL;
	359	now += 86400 - (now + 1) % 86400;
	360	hrtimer_start(&leap_timer, ktime_set(now, 0), HRTIMER_MODE_ABS);
	361	}
	362	}
80f22571 IM	363
	364	/*
	365	* Propagate a new txc->status value into the NTP state:
	366	*/
	367	static inline void process_adj_status(struct timex txc, struct timespec ts)
	368	{
80f22571 IM	369	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
	370	time_state = TIME_OK;
	371	time_status = STA_UNSYNC;
	372	}
80f22571 IM	373
	374	/*
	375	* If we turn on PLL adjustments then reset the
	376	* reference time to current time.
	377	*/
	378	if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
7e1b5847	379	time_reftime = get_seconds();
80f22571	380
a2a5ac86 JS	381	/* only set allowed bits */
a2a5ac86 JS	382	time_status &= STA_RONLY;
80f22571 IM	383	time_status \|= txc->status & ~STA_RONLY;
	384
	385	switch (time_state) {
	386	case TIME_OK:
e9629165	387	ntp_start_leap_timer(ts);
80f22571 IM	388	break;
	389	case TIME_INS:
	390	case TIME_DEL:
	391	time_state = TIME_OK;
e9629165	392	ntp_start_leap_timer(ts);
80f22571 IM	393	case TIME_WAIT:
	394	if (!(time_status & (STA_INS \| STA_DEL)))
	395	time_state = TIME_OK;
	396	break;
	397	case TIME_OOP:
	398	hrtimer_restart(&leap_timer);
	399	break;
	400	}
	401	}
	402	/*
	403	* Called with the xtime lock held, so we can access and modify
	404	* all the global NTP state:
	405	*/
	406	static inline void process_adjtimex_modes(struct timex txc, struct timespec ts)
	407	{
	408	if (txc->modes & ADJ_STATUS)
	409	process_adj_status(txc, ts);
	410
	411	if (txc->modes & ADJ_NANO)
	412	time_status \|= STA_NANO;
e9629165	413
80f22571 IM	414	if (txc->modes & ADJ_MICRO)
	415	time_status &= ~STA_NANO;
	416
	417	if (txc->modes & ADJ_FREQUENCY) {
2b9d1496	418	time_freq = txc->freq * PPM_SCALE;
80f22571 IM	419	time_freq = min(time_freq, MAXFREQ_SCALED);
	420	time_freq = max(time_freq, -MAXFREQ_SCALED);
	421	}
	422
	423	if (txc->modes & ADJ_MAXERROR)
	424	time_maxerror = txc->maxerror;
e9629165	425
80f22571 IM	426	if (txc->modes & ADJ_ESTERROR)
	427	time_esterror = txc->esterror;
	428
	429	if (txc->modes & ADJ_TIMECONST) {
	430	time_constant = txc->constant;
	431	if (!(time_status & STA_NANO))
	432	time_constant += 4;
	433	time_constant = min(time_constant, (long)MAXTC);
	434	time_constant = max(time_constant, 0l);
	435	}
	436
	437	if (txc->modes & ADJ_TAI && txc->constant > 0)
	438	time_tai = txc->constant;
	439
	440	if (txc->modes & ADJ_OFFSET)
	441	ntp_update_offset(txc->offset);
e9629165	442
80f22571 IM	443	if (txc->modes & ADJ_TICK)
	444	tick_usec = txc->tick;
	445
	446	if (txc->modes & (ADJ_TICK\|ADJ_FREQUENCY\|ADJ_OFFSET))
	447	ntp_update_frequency();
	448	}
	449
53bbfa9e IM	450	/*
53bbfa9e IM	451	* adjtimex mainly allows reading (and writing, if superuser) of
4c7ee8de JS	452	* kernel time-keeping variables. used by xntpd.
	453	*/
	454	int do_adjtimex(struct timex *txc)
	455	{
eea83d89	456	struct timespec ts;
4c7ee8de JS	457	int result;
4c7ee8de JS	458
916c7a85 RZ	459	/* Validate the data before disabling interrupts */
916c7a85 RZ	460	if (txc->modes & ADJ_ADJTIME) {
eea83d89	461	/* singleshot must not be used with any other mode bits */
916c7a85	462	if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
4c7ee8de	463	return -EINVAL;
916c7a85 RZ	464	if (!(txc->modes & ADJ_OFFSET_READONLY) &&
	465	!capable(CAP_SYS_TIME))
	466	return -EPERM;
	467	} else {
	468	/* In order to modify anything, you gotta be super-user! */
	469	if (txc->modes && !capable(CAP_SYS_TIME))
	470	return -EPERM;
	471
53bbfa9e IM	472	/*
	473	* if the quartz is off by more than 10% then
	474	* something is VERY wrong!
	475	*/
916c7a85 RZ	476	if (txc->modes & ADJ_TICK &&
	477	(txc->tick < 900000/USER_HZ \|\|
	478	txc->tick > 1100000/USER_HZ))
e9629165	479	return -EINVAL;
916c7a85 RZ	480
	481	if (txc->modes & ADJ_STATUS && time_state != TIME_OK)
	482	hrtimer_cancel(&leap_timer);
52bfb360	483	}
4c7ee8de	484
7dffa3c6 RZ	485	getnstimeofday(&ts);
7dffa3c6 RZ	486
4c7ee8de	487	write_seqlock_irq(&xtime_lock);
4c7ee8de	488
916c7a85 RZ	489	if (txc->modes & ADJ_ADJTIME) {
	490	long save_adjust = time_adjust;
	491
	492	if (!(txc->modes & ADJ_OFFSET_READONLY)) {
	493	/* adjtime() is independent from ntp_adjtime() */
	494	time_adjust = txc->offset;
	495	ntp_update_frequency();
	496	}
	497	txc->offset = save_adjust;
e9629165	498	} else {
ee9851b2	499
e9629165 IM	500	/* If there are input parameters, then process them: */
	501	if (txc->modes)
	502	process_adjtimex_modes(txc, &ts);
eea83d89	503
e9629165	504	txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
916c7a85	505	NTP_SCALE_SHIFT);
e9629165 IM	506	if (!(time_status & STA_NANO))
	507	txc->offset /= NSEC_PER_USEC;
	508	}
916c7a85	509
eea83d89	510	result = time_state; /* mostly `TIME_OK' */
ee9851b2	511	if (time_status & (STA_UNSYNC\|STA_CLOCKERR))
4c7ee8de JS	512	result = TIME_ERROR;
4c7ee8de JS	513
d40e944c	514	txc->freq = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
2b9d1496	515	PPM_SCALE_INV, NTP_SCALE_SHIFT);
4c7ee8de JS	516	txc->maxerror = time_maxerror;
	517	txc->esterror = time_esterror;
	518	txc->status = time_status;
	519	txc->constant = time_constant;
70bc42f9	520	txc->precision = 1;
074b3b87	521	txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
4c7ee8de	522	txc->tick = tick_usec;
153b5d05	523	txc->tai = time_tai;
4c7ee8de JS	524
	525	/* PPS is not implemented, so these are zero */
	526	txc->ppsfreq = 0;
	527	txc->jitter = 0;
	528	txc->shift = 0;
	529	txc->stabil = 0;
	530	txc->jitcnt = 0;
	531	txc->calcnt = 0;
	532	txc->errcnt = 0;
	533	txc->stbcnt = 0;
e9629165	534
4c7ee8de	535	write_sequnlock_irq(&xtime_lock);
ee9851b2	536
eea83d89 RZ	537	txc->time.tv_sec = ts.tv_sec;
	538	txc->time.tv_usec = ts.tv_nsec;
	539	if (!(time_status & STA_NANO))
	540	txc->time.tv_usec /= NSEC_PER_USEC;
ee9851b2	541
82644459	542	notify_cmos_timer();
ee9851b2 RZ	543
ee9851b2 RZ	544	return result;
4c7ee8de	545	}
10a398d0 RZ	546
	547	static int __init ntp_tick_adj_setup(char *str)
	548	{
	549	ntp_tick_adj = simple_strtol(str, NULL, 0);
069569e0 IM	550	ntp_tick_adj <<= NTP_SCALE_SHIFT;
069569e0 IM	551
10a398d0 RZ	552	return 1;
	553	}
	554
	555	__setup("ntp_tick_adj=", ntp_tick_adj_setup);
7dffa3c6 RZ	556
	557	void __init ntp_init(void)
	558	{
	559	ntp_clear();
	560	hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
	561	leap_timer.function = ntp_leap_second;
	562	}