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

/*
 * linux/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/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 <linux/math64.h>
#include <linux/clocksource.h>
#include <asm/timex.h>

/*
 * Timekeeping variables
 */
unsigned long tick_usec = TICK_USEC; 		/* USER_HZ period (usec) */
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)

/*
 * phase-lock loop variables
 */
/* TIME_ERROR prevents overwriting the CMOS clock */
static int time_state = TIME_OK;	/* clock synchronization status	*/
int time_status = STA_UNSYNC;		/* clock status bits		*/
static long time_tai;			/* TAI offset (s)		*/
static s64 time_offset;			/* time adjustment (ns)		*/
static long time_constant = 2;		/* pll time constant		*/
long time_maxerror = NTP_PHASE_LIMIT;	/* maximum error (us)		*/
long time_esterror = NTP_PHASE_LIMIT;	/* estimated error (us)		*/
static s64 time_freq;			/* frequency offset (scaled ns/s)*/
static long time_reftime;		/* time at last adjustment (s)	*/
long time_adjust;
static long ntp_tick_adj;

static void ntp_update_frequency(void)
{
	u64 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_length_base = second_length;

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

static void ntp_update_offset(long offset)
{
	long mtemp;
	s64 freq_adj;

	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).
	 */
	if (time_status & STA_FREQHOLD || time_reftime == 0)
		time_reftime = xtime.tv_sec;
	mtemp = xtime.tv_sec - time_reftime;
	time_reftime = xtime.tv_sec;

	freq_adj = (s64)offset * mtemp;
	freq_adj <<= NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant);
	time_status &= ~STA_MODE;
	if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
		freq_adj += div_s64((s64)offset << (NTP_SCALE_SHIFT - SHIFT_FLL),
				    mtemp);
		time_status |= STA_MODE;
	}
	freq_adj += time_freq;
	freq_adj = min(freq_adj, MAXFREQ_SCALED);
	time_freq = max(freq_adj, -MAXFREQ_SCALED);

	time_offset = div_s64((s64)offset << 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_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");
		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_irq(&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 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 (unlikely(time_adjust)) {
		if (time_adjust > MAX_TICKADJ) {
			time_adjust -= MAX_TICKADJ;
			tick_length += MAX_TICKADJ_SCALED;
		} else if (time_adjust < -MAX_TICKADJ) {
			time_adjust += MAX_TICKADJ;
			tick_length -= MAX_TICKADJ_SCALED;
		} else {
			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(unsigned long dummy);

static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);

static void sync_cmos_clock(unsigned long dummy)
{
	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;
	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.
 */
int do_adjtimex(struct timex *txc)
{
	struct timespec ts;
	long save_adjust, sec;
	int result;

	/* In order to modify anything, you gotta be super-user! */
	if (txc->modes && !capable(CAP_SYS_TIME))
		return -EPERM;

	/* Now we validate the data before disabling interrupts */

	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) {
		/* singleshot must not be used with any other mode bits */
		if (txc->modes & ~ADJ_OFFSET_SS_READ)
			return -EINVAL;
	}

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

	/* If there are input parameters, then process them */
	if (txc->modes) {
		if (txc->modes & ADJ_STATUS) {
			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;
			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)
			time_status |= STA_NANO;
		if (txc->modes & ADJ_MICRO)
			time_status &= ~STA_NANO;

		if (txc->modes & ADJ_FREQUENCY) {
			time_freq = (s64)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) {
			if (txc->modes == ADJ_OFFSET_SINGLESHOT)
				/* adjtime() is independent from ntp_adjtime() */
				time_adjust = txc->offset;
			else
				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();
	}

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

	if ((txc->modes == ADJ_OFFSET_SINGLESHOT) ||
	    (txc->modes == ADJ_OFFSET_SS_READ))
		txc->offset = save_adjust;
	else {
		txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
					  NTP_SCALE_SHIFT);
		if (!(time_status & STA_NANO))
			txc->offset /= NSEC_PER_USEC;
	}
	txc->freq	   = shift_right((s32)(time_freq >> PPM_SCALE_INV_SHIFT) *
					 (s64)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	/*
	2	* linux/kernel/time/ntp.c
	3	*
	4	* NTP state machine interfaces and logic.
	5	*
	6	* This code was mainly moved from kernel/timer.c and kernel/time.c
	7	* Please see those files for relevant copyright info and historical
	8	* changelogs.
	9	*/
	10
	11	#include <linux/mm.h>
	12	#include <linux/time.h>
82644459	13	#include <linux/timer.h>
4c7ee8de	14	#include <linux/timex.h>
e8edc6e0 AD	15	#include <linux/jiffies.h>
e8edc6e0 AD	16	#include <linux/hrtimer.h>
aa0ac365	17	#include <linux/capability.h>
71abb3af	18	#include <linux/math64.h>
7dffa3c6	19	#include <linux/clocksource.h>
4c7ee8de	20	#include <asm/timex.h>
4c7ee8de	21
b0ee7556 RZ	22	/*
	23	* Timekeeping variables
	24	*/
	25	unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
	26	unsigned long tick_nsec; /* ACTHZ period (nsec) */
8383c423 RZ	27	u64 tick_length;
8383c423 RZ	28	static u64 tick_length_base;
b0ee7556	29
7dffa3c6 RZ	30	static struct hrtimer leap_timer;
7dffa3c6 RZ	31
8f807f8d RZ	32	#define MAX_TICKADJ 500 /* microsecs */
8f807f8d RZ	33	#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
7fc5c784	34	NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
4c7ee8de	35
	36	/*
	37	* phase-lock loop variables
	38	*/
	39	/* TIME_ERROR prevents overwriting the CMOS clock */
70bc42f9	40	static int time_state = TIME_OK; /* clock synchronization status */
4c7ee8de	41	int time_status = STA_UNSYNC; /* clock status bits */
153b5d05	42	static long time_tai; /* TAI offset (s) */
ee9851b2	43	static s64 time_offset; /* time adjustment (ns) */
70bc42f9	44	static long time_constant = 2; /* pll time constant */
4c7ee8de	45	long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
4c7ee8de	46	long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
074b3b87	47	static s64 time_freq; /* frequency offset (scaled ns/s)*/
70bc42f9	48	static long time_reftime; /* time at last adjustment (s) */
4c7ee8de	49	long time_adjust;
10a398d0	50	static long ntp_tick_adj;
4c7ee8de	51
70bc42f9 AB	52	static void ntp_update_frequency(void)
70bc42f9 AB	53	{
f4304ab2	54	u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
7fc5c784 RZ	55	<< NTP_SCALE_SHIFT;
7fc5c784 RZ	56	second_length += (s64)ntp_tick_adj << NTP_SCALE_SHIFT;
074b3b87	57	second_length += time_freq;
70bc42f9	58
f4304ab2	59	tick_length_base = second_length;
70bc42f9	60
7fc5c784	61	tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
71abb3af	62	tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ);
70bc42f9 AB	63	}
70bc42f9 AB	64
ee9851b2 RZ	65	static void ntp_update_offset(long offset)
	66	{
	67	long mtemp;
	68	s64 freq_adj;
	69
	70	if (!(time_status & STA_PLL))
	71	return;
	72
eea83d89	73	if (!(time_status & STA_NANO))
9f14f669	74	offset *= NSEC_PER_USEC;
ee9851b2 RZ	75
	76	/*
	77	* Scale the phase adjustment and
	78	* clamp to the operating range.
	79	*/
9f14f669 RZ	80	offset = min(offset, MAXPHASE);
9f14f669 RZ	81	offset = max(offset, -MAXPHASE);
ee9851b2 RZ	82
	83	/*
	84	* Select how the frequency is to be controlled
	85	* and in which mode (PLL or FLL).
	86	*/
	87	if (time_status & STA_FREQHOLD \|\| time_reftime == 0)
	88	time_reftime = xtime.tv_sec;
	89	mtemp = xtime.tv_sec - time_reftime;
	90	time_reftime = xtime.tv_sec;
	91
9f14f669	92	freq_adj = (s64)offset * mtemp;
7fc5c784	93	freq_adj <<= NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant);
eea83d89 RZ	94	time_status &= ~STA_MODE;
eea83d89 RZ	95	if (mtemp >= MINSEC && (time_status & STA_FLL \|\| mtemp > MAXSEC)) {
7fc5c784	96	freq_adj += div_s64((s64)offset << (NTP_SCALE_SHIFT - SHIFT_FLL),
074b3b87	97	mtemp);
eea83d89 RZ	98	time_status \|= STA_MODE;
eea83d89 RZ	99	}
ee9851b2	100	freq_adj += time_freq;
074b3b87 RZ	101	freq_adj = min(freq_adj, MAXFREQ_SCALED);
074b3b87 RZ	102	time_freq = max(freq_adj, -MAXFREQ_SCALED);
9f14f669	103
7fc5c784	104	time_offset = div_s64((s64)offset << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
ee9851b2 RZ	105	}
ee9851b2 RZ	106
b0ee7556 RZ	107	/**
	108	* ntp_clear - Clears the NTP state variables
	109	*
	110	* Must be called while holding a write on the xtime_lock
	111	*/
	112	void ntp_clear(void)
	113	{
	114	time_adjust = 0; /* stop active adjtime() */
	115	time_status \|= STA_UNSYNC;
	116	time_maxerror = NTP_PHASE_LIMIT;
	117	time_esterror = NTP_PHASE_LIMIT;
	118
	119	ntp_update_frequency();
	120
	121	tick_length = tick_length_base;
3d3675cc	122	time_offset = 0;
b0ee7556 RZ	123	}
b0ee7556 RZ	124
4c7ee8de	125	/*
7dffa3c6 RZ	126	* Leap second processing. If in leap-insert state at the end of the
	127	* day, the system clock is set back one second; if in leap-delete
	128	* state, the system clock is set ahead one second.
4c7ee8de	129	*/
7dffa3c6	130	static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
4c7ee8de	131	{
7dffa3c6	132	enum hrtimer_restart res = HRTIMER_NORESTART;
4c7ee8de	133
7dffa3c6	134	write_seqlock_irq(&xtime_lock);
4c7ee8de	135
4c7ee8de	136	switch (time_state) {
4c7ee8de	137	case TIME_OK:
4c7ee8de	138	break;
4c7ee8de	139	case TIME_INS:
7dffa3c6 RZ	140	xtime.tv_sec--;
	141	wall_to_monotonic.tv_sec++;
	142	time_state = TIME_OOP;
	143	printk(KERN_NOTICE "Clock: "
	144	"inserting leap second 23:59:60 UTC\n");
cc584b21	145	hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
7dffa3c6	146	res = HRTIMER_RESTART;
4c7ee8de	147	break;
4c7ee8de	148	case TIME_DEL:
7dffa3c6 RZ	149	xtime.tv_sec++;
	150	time_tai--;
	151	wall_to_monotonic.tv_sec--;
	152	time_state = TIME_WAIT;
	153	printk(KERN_NOTICE "Clock: "
	154	"deleting leap second 23:59:59 UTC\n");
4c7ee8de	155	break;
4c7ee8de	156	case TIME_OOP:
153b5d05	157	time_tai++;
4c7ee8de	158	time_state = TIME_WAIT;
7dffa3c6	159	/* fall through */
4c7ee8de	160	case TIME_WAIT:
4c7ee8de	161	if (!(time_status & (STA_INS \| STA_DEL)))
ee9851b2	162	time_state = TIME_OK;
7dffa3c6 RZ	163	break;
	164	}
	165	update_vsyscall(&xtime, clock);
	166
	167	write_sequnlock_irq(&xtime_lock);
	168
	169	return res;
	170	}
	171
	172	/*
	173	* this routine handles the overflow of the microsecond field
	174	*
	175	* The tricky bits of code to handle the accurate clock support
	176	* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
	177	* They were originally developed for SUN and DEC kernels.
	178	* All the kudos should go to Dave for this stuff.
	179	*/
	180	void second_overflow(void)
	181	{
	182	s64 time_adj;
	183
	184	/* Bump the maxerror field */
	185	time_maxerror += MAXFREQ / NSEC_PER_USEC;
	186	if (time_maxerror > NTP_PHASE_LIMIT) {
	187	time_maxerror = NTP_PHASE_LIMIT;
	188	time_status \|= STA_UNSYNC;
4c7ee8de	189	}
	190
	191	/*
f1992393 RZ	192	* Compute the phase adjustment for the next second. The offset is
f1992393 RZ	193	* reduced by a fixed factor times the time constant.
4c7ee8de	194	*/
b0ee7556	195	tick_length = tick_length_base;
f1992393	196	time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
3d3675cc	197	time_offset -= time_adj;
9f14f669	198	tick_length += time_adj;
4c7ee8de	199
8f807f8d RZ	200	if (unlikely(time_adjust)) {
	201	if (time_adjust > MAX_TICKADJ) {
	202	time_adjust -= MAX_TICKADJ;
	203	tick_length += MAX_TICKADJ_SCALED;
	204	} else if (time_adjust < -MAX_TICKADJ) {
	205	time_adjust += MAX_TICKADJ;
	206	tick_length -= MAX_TICKADJ_SCALED;
	207	} else {
8f807f8d	208	tick_length += (s64)(time_adjust * NSEC_PER_USEC /
7fc5c784	209	NTP_INTERVAL_FREQ) << NTP_SCALE_SHIFT;
bb1d8605	210	time_adjust = 0;
8f807f8d	211	}
4c7ee8de	212	}
	213	}
	214
82644459	215	#ifdef CONFIG_GENERIC_CMOS_UPDATE
4c7ee8de	216
82644459 TG	217	/* Disable the cmos update - used by virtualization and embedded */
	218	int no_sync_cmos_clock __read_mostly;
	219
	220	static void sync_cmos_clock(unsigned long dummy);
	221
	222	static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
	223
	224	static void sync_cmos_clock(unsigned long dummy)
	225	{
	226	struct timespec now, next;
	227	int fail = 1;
	228
	229	/*
	230	* If we have an externally synchronized Linux clock, then update
	231	* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	232	* called as close as possible to 500 ms before the new second starts.
	233	* This code is run on a timer. If the clock is set, that timer
	234	* may not expire at the correct time. Thus, we adjust...
	235	*/
	236	if (!ntp_synced())
	237	/*
	238	* Not synced, exit, do not restart a timer (if one is
	239	* running, let it run out).
	240	*/
	241	return;
	242
	243	getnstimeofday(&now);
fa6a1a55	244	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
82644459 TG	245	fail = update_persistent_clock(now);
	246
	247	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
	248	if (next.tv_nsec <= 0)
	249	next.tv_nsec += NSEC_PER_SEC;
	250
	251	if (!fail)
	252	next.tv_sec = 659;
	253	else
	254	next.tv_sec = 0;
	255
	256	if (next.tv_nsec >= NSEC_PER_SEC) {
	257	next.tv_sec++;
	258	next.tv_nsec -= NSEC_PER_SEC;
	259	}
	260	mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
	261	}
	262
	263	static void notify_cmos_timer(void)
4c7ee8de	264	{
298a5df4	265	if (!no_sync_cmos_clock)
82644459	266	mod_timer(&sync_cmos_timer, jiffies + 1);
4c7ee8de	267	}
4c7ee8de	268
82644459 TG	269	#else
	270	static inline void notify_cmos_timer(void) { }
	271	#endif
	272
4c7ee8de	273	/* adjtimex mainly allows reading (and writing, if superuser) of
	274	* kernel time-keeping variables. used by xntpd.
	275	*/
	276	int do_adjtimex(struct timex *txc)
	277	{
eea83d89	278	struct timespec ts;
7dffa3c6	279	long save_adjust, sec;
4c7ee8de	280	int result;
	281
	282	/* In order to modify anything, you gotta be super-user! */
	283	if (txc->modes && !capable(CAP_SYS_TIME))
	284	return -EPERM;
	285
	286	/* Now we validate the data before disabling interrupts */
	287
52bfb360	288	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT) {
eea83d89 RZ	289	/* singleshot must not be used with any other mode bits */
eea83d89 RZ	290	if (txc->modes & ~ADJ_OFFSET_SS_READ)
4c7ee8de	291	return -EINVAL;
52bfb360	292	}
4c7ee8de	293
4c7ee8de	294	/* if the quartz is off by more than 10% something is VERY wrong ! */
	295	if (txc->modes & ADJ_TICK)
	296	if (txc->tick < 900000/USER_HZ \|\|
	297	txc->tick > 1100000/USER_HZ)
	298	return -EINVAL;
	299
7dffa3c6 RZ	300	if (time_state != TIME_OK && txc->modes & ADJ_STATUS)
	301	hrtimer_cancel(&leap_timer);
	302	getnstimeofday(&ts);
	303
4c7ee8de	304	write_seqlock_irq(&xtime_lock);
4c7ee8de	305
4c7ee8de	306	/* Save for later - semantics of adjtime is to return old value */
8f807f8d	307	save_adjust = time_adjust;
4c7ee8de	308
4c7ee8de	309	/* If there are input parameters, then process them */
ee9851b2	310	if (txc->modes) {
eea83d89 RZ	311	if (txc->modes & ADJ_STATUS) {
	312	if ((time_status & STA_PLL) &&
	313	!(txc->status & STA_PLL)) {
	314	time_state = TIME_OK;
	315	time_status = STA_UNSYNC;
	316	}
	317	/* only set allowed bits */
	318	time_status &= STA_RONLY;
	319	time_status \|= txc->status & ~STA_RONLY;
7dffa3c6 RZ	320
	321	switch (time_state) {
	322	case TIME_OK:
	323	start_timer:
	324	sec = ts.tv_sec;
	325	if (time_status & STA_INS) {
	326	time_state = TIME_INS;
	327	sec += 86400 - sec % 86400;
	328	hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
	329	} else if (time_status & STA_DEL) {
	330	time_state = TIME_DEL;
	331	sec += 86400 - (sec + 1) % 86400;
	332	hrtimer_start(&leap_timer, ktime_set(sec, 0), HRTIMER_MODE_ABS);
	333	}
	334	break;
	335	case TIME_INS:
	336	case TIME_DEL:
	337	time_state = TIME_OK;
	338	goto start_timer;
	339	break;
	340	case TIME_WAIT:
	341	if (!(time_status & (STA_INS \| STA_DEL)))
	342	time_state = TIME_OK;
	343	break;
	344	case TIME_OOP:
	345	hrtimer_restart(&leap_timer);
	346	break;
	347	}
eea83d89 RZ	348	}
	349
	350	if (txc->modes & ADJ_NANO)
	351	time_status \|= STA_NANO;
	352	if (txc->modes & ADJ_MICRO)
	353	time_status &= ~STA_NANO;
ee9851b2 RZ	354
ee9851b2 RZ	355	if (txc->modes & ADJ_FREQUENCY) {
074b3b87 RZ	356	time_freq = (s64)txc->freq * PPM_SCALE;
	357	time_freq = min(time_freq, MAXFREQ_SCALED);
	358	time_freq = max(time_freq, -MAXFREQ_SCALED);
4c7ee8de	359	}
ee9851b2	360
eea83d89	361	if (txc->modes & ADJ_MAXERROR)
ee9851b2	362	time_maxerror = txc->maxerror;
eea83d89	363	if (txc->modes & ADJ_ESTERROR)
ee9851b2	364	time_esterror = txc->esterror;
4c7ee8de	365
ee9851b2	366	if (txc->modes & ADJ_TIMECONST) {
eea83d89 RZ	367	time_constant = txc->constant;
	368	if (!(time_status & STA_NANO))
	369	time_constant += 4;
	370	time_constant = min(time_constant, (long)MAXTC);
	371	time_constant = max(time_constant, 0l);
4c7ee8de	372	}
4c7ee8de	373
153b5d05 RZ	374	if (txc->modes & ADJ_TAI && txc->constant > 0)
	375	time_tai = txc->constant;
	376
ee9851b2 RZ	377	if (txc->modes & ADJ_OFFSET) {
	378	if (txc->modes == ADJ_OFFSET_SINGLESHOT)
	379	/* adjtime() is independent from ntp_adjtime() */
	380	time_adjust = txc->offset;
	381	else
	382	ntp_update_offset(txc->offset);
4c7ee8de	383	}
ee9851b2 RZ	384	if (txc->modes & ADJ_TICK)
	385	tick_usec = txc->tick;
	386
	387	if (txc->modes & (ADJ_TICK\|ADJ_FREQUENCY\|ADJ_OFFSET))
	388	ntp_update_frequency();
	389	}
eea83d89 RZ	390
eea83d89 RZ	391	result = time_state; /* mostly `TIME_OK' */
ee9851b2	392	if (time_status & (STA_UNSYNC\|STA_CLOCKERR))
4c7ee8de	393	result = TIME_ERROR;
4c7ee8de	394
52bfb360	395	if ((txc->modes == ADJ_OFFSET_SINGLESHOT) \|\|
ee9851b2	396	(txc->modes == ADJ_OFFSET_SS_READ))
d62ac21a	397	txc->offset = save_adjust;
eea83d89	398	else {
9f14f669	399	txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
7fc5c784	400	NTP_SCALE_SHIFT);
eea83d89 RZ	401	if (!(time_status & STA_NANO))
	402	txc->offset /= NSEC_PER_USEC;
	403	}
074b3b87 RZ	404	txc->freq = shift_right((s32)(time_freq >> PPM_SCALE_INV_SHIFT) *
074b3b87 RZ	405	(s64)PPM_SCALE_INV,
7fc5c784	406	NTP_SCALE_SHIFT);
4c7ee8de	407	txc->maxerror = time_maxerror;
	408	txc->esterror = time_esterror;
	409	txc->status = time_status;
	410	txc->constant = time_constant;
70bc42f9	411	txc->precision = 1;
074b3b87	412	txc->tolerance = MAXFREQ_SCALED / PPM_SCALE;
4c7ee8de	413	txc->tick = tick_usec;
153b5d05	414	txc->tai = time_tai;
4c7ee8de	415
	416	/* PPS is not implemented, so these are zero */
	417	txc->ppsfreq = 0;
	418	txc->jitter = 0;
	419	txc->shift = 0;
	420	txc->stabil = 0;
	421	txc->jitcnt = 0;
	422	txc->calcnt = 0;
	423	txc->errcnt = 0;
	424	txc->stbcnt = 0;
	425	write_sequnlock_irq(&xtime_lock);
ee9851b2	426
eea83d89 RZ	427	txc->time.tv_sec = ts.tv_sec;
	428	txc->time.tv_usec = ts.tv_nsec;
	429	if (!(time_status & STA_NANO))
	430	txc->time.tv_usec /= NSEC_PER_USEC;
ee9851b2	431
82644459	432	notify_cmos_timer();
ee9851b2 RZ	433
ee9851b2 RZ	434	return result;
4c7ee8de	435	}
10a398d0 RZ	436
	437	static int __init ntp_tick_adj_setup(char *str)
	438	{
	439	ntp_tick_adj = simple_strtol(str, NULL, 0);
	440	return 1;
	441	}
	442
	443	__setup("ntp_tick_adj=", ntp_tick_adj_setup);
7dffa3c6 RZ	444
	445	void __init ntp_init(void)
	446	{
	447	ntp_clear();
	448	hrtimer_init(&leap_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
	449	leap_timer.function = ntp_leap_second;
	450	}