[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 <asm/div64.h>
#include <asm/timex.h>

/*
 * Timekeeping variables
 */
unsigned long tick_usec = TICK_USEC; 		/* USER_HZ period (usec) */
unsigned long tick_nsec;			/* ACTHZ period (nsec) */
static u64 tick_length, tick_length_base;

#define MAX_TICKADJ		500		/* microsecs */
#define MAX_TICKADJ_SCALED	(((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
				  TICK_LENGTH_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 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)		*/
long time_freq;				/* frequency offset (scaled ppm)*/
static long time_reftime;		/* time at last adjustment (s)	*/
long time_adjust;

#define CLOCK_TICK_OVERFLOW	(LATCH * HZ - CLOCK_TICK_RATE)
#define CLOCK_TICK_ADJUST	(((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
					(s64)CLOCK_TICK_RATE)

static void ntp_update_frequency(void)
{
	u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
				<< TICK_LENGTH_SHIFT;
	second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
	second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);

	tick_length_base = second_length;

	do_div(second_length, HZ);
	tick_nsec = second_length >> TICK_LENGTH_SHIFT;

	do_div(tick_length_base, 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;
}

/*
 * 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)
{
	long time_adj;

	/* Bump the maxerror field */
	time_maxerror += MAXFREQ >> SHIFT_USEC;
	if (time_maxerror > NTP_PHASE_LIMIT) {
		time_maxerror = NTP_PHASE_LIMIT;
		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++;
			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_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.
	 */
	tick_length = tick_length_base;
	time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
	time_offset -= time_adj;
	tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);

	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) << TICK_LENGTH_SHIFT;
			time_adjust = 0;
		}
	}
}

/*
 * Return how long ticks are at the moment, that is, how much time
 * update_wall_time_one_tick will add to xtime next time we call it
 * (assuming no calls to do_adjtimex in the meantime).
 * The return value is in fixed-point nanoseconds shifted by the
 * specified number of bits to the right of the binary point.
 * This function has no side-effects.
 */
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);

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(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.
 */
int do_adjtimex(struct timex *txc)
{
	long mtemp, save_adjust, rem;
	s64 freq_adj, temp64;
	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_SINGLESHOT)
			return -EINVAL;

	if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
	  /* adjustment Offset limited to +- .512 seconds */
		if (txc->offset <= - MAXPHASE || txc->offset >= MAXPHASE )
			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;

	write_seqlock_irq(&xtime_lock);
	result = time_state;	/* mostly `TIME_OK' */

	/* Save for later - semantics of adjtime is to return old value */
	save_adjust = time_adjust;

#if 0	/* STA_CLOCKERR is never set yet */
	time_status &= ~STA_CLOCKERR;		/* reset STA_CLOCKERR */
#endif
	/* If there are input parameters, then process them */
	if (txc->modes)
	{
	    if (txc->modes & ADJ_STATUS)	/* only set allowed bits */
		time_status =  (txc->status & ~STA_RONLY) |
			      (time_status & STA_RONLY);

	    if (txc->modes & ADJ_FREQUENCY) {	/* p. 22 */
		if (txc->freq > MAXFREQ || txc->freq < -MAXFREQ) {
		    result = -EINVAL;
		    goto leave;
		}
		time_freq = ((s64)txc->freq * NSEC_PER_USEC)
				>> (SHIFT_USEC - SHIFT_NSEC);
	    }

	    if (txc->modes & ADJ_MAXERROR) {
		if (txc->maxerror < 0 || txc->maxerror >= NTP_PHASE_LIMIT) {
		    result = -EINVAL;
		    goto leave;
		}
		time_maxerror = txc->maxerror;
	    }

	    if (txc->modes & ADJ_ESTERROR) {
		if (txc->esterror < 0 || txc->esterror >= NTP_PHASE_LIMIT) {
		    result = -EINVAL;
		    goto leave;
		}
		time_esterror = txc->esterror;
	    }

	    if (txc->modes & ADJ_TIMECONST) {	/* p. 24 */
		if (txc->constant < 0) {	/* NTP v4 uses values > 6 */
		    result = -EINVAL;
		    goto leave;
		}
		time_constant = min(txc->constant + 4, (long)MAXTC);
	    }

	    if (txc->modes & ADJ_OFFSET) {	/* values checked earlier */
		if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
		    /* adjtime() is independent from ntp_adjtime() */
		    time_adjust = txc->offset;
		}
		else if (time_status & STA_PLL) {
		    time_offset = txc->offset * NSEC_PER_USEC;

		    /*
		     * Scale the phase adjustment and
		     * clamp to the operating range.
		     */
		    time_offset = min(time_offset, (s64)MAXPHASE * NSEC_PER_USEC);
		    time_offset = max(time_offset, (s64)-MAXPHASE * NSEC_PER_USEC);

		    /*
		     * Select whether the frequency is to be controlled
		     * and in which mode (PLL or FLL). Clamp to the operating
		     * range. Ugly multiply/divide should be replaced someday.
		     */

		    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 = time_offset * mtemp;
		    freq_adj = shift_right(freq_adj, time_constant * 2 +
					   (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
		    if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
			temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
			if (time_offset < 0) {
			    temp64 = -temp64;
			    do_div(temp64, mtemp);
			    freq_adj -= temp64;
			} else {
			    do_div(temp64, mtemp);
			    freq_adj += temp64;
			}
		    }
		    freq_adj += time_freq;
		    freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
		    time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
		    time_offset = div_long_long_rem_signed(time_offset,
							   NTP_INTERVAL_FREQ,
							   &rem);
		    time_offset <<= SHIFT_UPDATE;
		} /* STA_PLL */
	    } /* txc->modes & ADJ_OFFSET */
	    if (txc->modes & ADJ_TICK)
		tick_usec = txc->tick;

	    if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
		    ntp_update_frequency();
	} /* txc->modes */
leave:	if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
		result = TIME_ERROR;

	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
		txc->offset = save_adjust;
	else
		txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) *
	    			NTP_INTERVAL_FREQ / 1000;
	txc->freq	   = (time_freq / NSEC_PER_USEC) <<
				(SHIFT_USEC - SHIFT_NSEC);
	txc->maxerror	   = time_maxerror;
	txc->esterror	   = time_esterror;
	txc->status	   = time_status;
	txc->constant	   = time_constant;
	txc->precision	   = 1;
	txc->tolerance	   = MAXFREQ;
	txc->tick	   = tick_usec;

	/* 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);
	do_gettimeofday(&txc->time);
	notify_cmos_timer();
	return(result);
}
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>
4c7ee8de	18	#include <asm/div64.h>
	19	#include <asm/timex.h>
	20
b0ee7556 RZ	21	/*
	22	* Timekeeping variables
	23	*/
	24	unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
	25	unsigned long tick_nsec; /* ACTHZ period (nsec) */
	26	static u64 tick_length, tick_length_base;
	27
8f807f8d RZ	28	#define MAX_TICKADJ 500 /* microsecs */
8f807f8d RZ	29	#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
f4304ab2	30	TICK_LENGTH_SHIFT) / NTP_INTERVAL_FREQ)
4c7ee8de	31
	32	/*
	33	* phase-lock loop variables
	34	*/
	35	/* TIME_ERROR prevents overwriting the CMOS clock */
70bc42f9	36	static int time_state = TIME_OK; /* clock synchronization status */
4c7ee8de	37	int time_status = STA_UNSYNC; /* clock status bits */
d62ac21a	38	static s64 time_offset; /* time adjustment (ns) */
70bc42f9	39	static long time_constant = 2; /* pll time constant */
4c7ee8de	40	long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
4c7ee8de	41	long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
dc6a43e4	42	long time_freq; /* frequency offset (scaled ppm)*/
70bc42f9	43	static long time_reftime; /* time at last adjustment (s) */
4c7ee8de	44	long time_adjust;
4c7ee8de	45
70bc42f9 AB	46	#define CLOCK_TICK_OVERFLOW (LATCH * HZ - CLOCK_TICK_RATE)
	47	#define CLOCK_TICK_ADJUST (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
	48	(s64)CLOCK_TICK_RATE)
	49
	50	static void ntp_update_frequency(void)
	51	{
f4304ab2	52	u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
	53	<< TICK_LENGTH_SHIFT;
	54	second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
	55	second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
70bc42f9	56
f4304ab2	57	tick_length_base = second_length;
70bc42f9	58
f4304ab2	59	do_div(second_length, HZ);
	60	tick_nsec = second_length >> TICK_LENGTH_SHIFT;
	61
	62	do_div(tick_length_base, NTP_INTERVAL_FREQ);
70bc42f9 AB	63	}
70bc42f9 AB	64
b0ee7556 RZ	65	/**
	66	* ntp_clear - Clears the NTP state variables
	67	*
	68	* Must be called while holding a write on the xtime_lock
	69	*/
	70	void ntp_clear(void)
	71	{
	72	time_adjust = 0; /* stop active adjtime() */
	73	time_status \|= STA_UNSYNC;
	74	time_maxerror = NTP_PHASE_LIMIT;
	75	time_esterror = NTP_PHASE_LIMIT;
	76
	77	ntp_update_frequency();
	78
	79	tick_length = tick_length_base;
3d3675cc	80	time_offset = 0;
b0ee7556 RZ	81	}
b0ee7556 RZ	82
4c7ee8de	83	/*
	84	* this routine handles the overflow of the microsecond field
	85	*
	86	* The tricky bits of code to handle the accurate clock support
	87	* were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
	88	* They were originally developed for SUN and DEC kernels.
	89	* All the kudos should go to Dave for this stuff.
	90	*/
	91	void second_overflow(void)
	92	{
3d3675cc	93	long time_adj;
4c7ee8de	94
4c7ee8de	95	/* Bump the maxerror field */
97eebe13	96	time_maxerror += MAXFREQ >> SHIFT_USEC;
4c7ee8de	97	if (time_maxerror > NTP_PHASE_LIMIT) {
	98	time_maxerror = NTP_PHASE_LIMIT;
	99	time_status \|= STA_UNSYNC;
	100	}
	101
	102	/*
	103	* Leap second processing. If in leap-insert state at the end of the
	104	* day, the system clock is set back one second; if in leap-delete
	105	* state, the system clock is set ahead one second. The microtime()
	106	* routine or external clock driver will insure that reported time is
	107	* always monotonic. The ugly divides should be replaced.
	108	*/
	109	switch (time_state) {
	110	case TIME_OK:
	111	if (time_status & STA_INS)
	112	time_state = TIME_INS;
	113	else if (time_status & STA_DEL)
	114	time_state = TIME_DEL;
	115	break;
	116	case TIME_INS:
	117	if (xtime.tv_sec % 86400 == 0) {
	118	xtime.tv_sec--;
	119	wall_to_monotonic.tv_sec++;
4c7ee8de	120	time_state = TIME_OOP;
4c7ee8de	121	printk(KERN_NOTICE "Clock: inserting leap second "
	122	"23:59:60 UTC\n");
	123	}
	124	break;
	125	case TIME_DEL:
	126	if ((xtime.tv_sec + 1) % 86400 == 0) {
	127	xtime.tv_sec++;
	128	wall_to_monotonic.tv_sec--;
4c7ee8de	129	time_state = TIME_WAIT;
4c7ee8de	130	printk(KERN_NOTICE "Clock: deleting leap second "
	131	"23:59:59 UTC\n");
	132	}
	133	break;
	134	case TIME_OOP:
	135	time_state = TIME_WAIT;
	136	break;
	137	case TIME_WAIT:
	138	if (!(time_status & (STA_INS \| STA_DEL)))
	139	time_state = TIME_OK;
	140	}
	141
	142	/*
f1992393 RZ	143	* Compute the phase adjustment for the next second. The offset is
f1992393 RZ	144	* reduced by a fixed factor times the time constant.
4c7ee8de	145	*/
b0ee7556	146	tick_length = tick_length_base;
f1992393	147	time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
3d3675cc RZ	148	time_offset -= time_adj;
3d3675cc RZ	149	tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE);
4c7ee8de	150
8f807f8d RZ	151	if (unlikely(time_adjust)) {
	152	if (time_adjust > MAX_TICKADJ) {
	153	time_adjust -= MAX_TICKADJ;
	154	tick_length += MAX_TICKADJ_SCALED;
	155	} else if (time_adjust < -MAX_TICKADJ) {
	156	time_adjust += MAX_TICKADJ;
	157	tick_length -= MAX_TICKADJ_SCALED;
	158	} else {
8f807f8d	159	tick_length += (s64)(time_adjust * NSEC_PER_USEC /
f4304ab2	160	NTP_INTERVAL_FREQ) << TICK_LENGTH_SHIFT;
bb1d8605	161	time_adjust = 0;
8f807f8d	162	}
4c7ee8de	163	}
	164	}
	165
	166	/*
	167	* Return how long ticks are at the moment, that is, how much time
	168	* update_wall_time_one_tick will add to xtime next time we call it
	169	* (assuming no calls to do_adjtimex in the meantime).
	170	* The return value is in fixed-point nanoseconds shifted by the
	171	* specified number of bits to the right of the binary point.
	172	* This function has no side-effects.
	173	*/
	174	u64 current_tick_length(void)
	175	{
8f807f8d	176	return tick_length;
4c7ee8de	177	}
4c7ee8de	178
82644459	179	#ifdef CONFIG_GENERIC_CMOS_UPDATE
4c7ee8de	180
82644459 TG	181	/* Disable the cmos update - used by virtualization and embedded */
	182	int no_sync_cmos_clock __read_mostly;
	183
	184	static void sync_cmos_clock(unsigned long dummy);
	185
	186	static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
	187
	188	static void sync_cmos_clock(unsigned long dummy)
	189	{
	190	struct timespec now, next;
	191	int fail = 1;
	192
	193	/*
	194	* If we have an externally synchronized Linux clock, then update
	195	* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	196	* called as close as possible to 500 ms before the new second starts.
	197	* This code is run on a timer. If the clock is set, that timer
	198	* may not expire at the correct time. Thus, we adjust...
	199	*/
	200	if (!ntp_synced())
	201	/*
	202	* Not synced, exit, do not restart a timer (if one is
	203	* running, let it run out).
	204	*/
	205	return;
	206
	207	getnstimeofday(&now);
	208	if (abs(xtime.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
	209	fail = update_persistent_clock(now);
	210
	211	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
	212	if (next.tv_nsec <= 0)
	213	next.tv_nsec += NSEC_PER_SEC;
	214
	215	if (!fail)
	216	next.tv_sec = 659;
	217	else
	218	next.tv_sec = 0;
	219
	220	if (next.tv_nsec >= NSEC_PER_SEC) {
	221	next.tv_sec++;
	222	next.tv_nsec -= NSEC_PER_SEC;
	223	}
	224	mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next));
	225	}
	226
	227	static void notify_cmos_timer(void)
4c7ee8de	228	{
298a5df4	229	if (!no_sync_cmos_clock)
82644459	230	mod_timer(&sync_cmos_timer, jiffies + 1);
4c7ee8de	231	}
4c7ee8de	232
82644459 TG	233	#else
	234	static inline void notify_cmos_timer(void) { }
	235	#endif
	236
4c7ee8de	237	/* adjtimex mainly allows reading (and writing, if superuser) of
	238	* kernel time-keeping variables. used by xntpd.
	239	*/
	240	int do_adjtimex(struct timex *txc)
	241	{
d62ac21a	242	long mtemp, save_adjust, rem;
f1992393	243	s64 freq_adj, temp64;
4c7ee8de	244	int result;
	245
	246	/* In order to modify anything, you gotta be super-user! */
	247	if (txc->modes && !capable(CAP_SYS_TIME))
	248	return -EPERM;
	249
	250	/* Now we validate the data before disabling interrupts */
	251
	252	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
	253	/* singleshot must not be used with any other mode bits */
	254	if (txc->modes != ADJ_OFFSET_SINGLESHOT)
	255	return -EINVAL;
	256
	257	if (txc->modes != ADJ_OFFSET_SINGLESHOT && (txc->modes & ADJ_OFFSET))
	258	/* adjustment Offset limited to +- .512 seconds */
	259	if (txc->offset <= - MAXPHASE \|\| txc->offset >= MAXPHASE )
	260	return -EINVAL;
	261
	262	/* if the quartz is off by more than 10% something is VERY wrong ! */
	263	if (txc->modes & ADJ_TICK)
	264	if (txc->tick < 900000/USER_HZ \|\|
	265	txc->tick > 1100000/USER_HZ)
	266	return -EINVAL;
	267
	268	write_seqlock_irq(&xtime_lock);
	269	result = time_state; /* mostly `TIME_OK' */
	270
	271	/* Save for later - semantics of adjtime is to return old value */
8f807f8d	272	save_adjust = time_adjust;
4c7ee8de	273
	274	#if 0 /* STA_CLOCKERR is never set yet */
	275	time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */
	276	#endif
	277	/* If there are input parameters, then process them */
	278	if (txc->modes)
	279	{
	280	if (txc->modes & ADJ_STATUS) /* only set allowed bits */
	281	time_status = (txc->status & ~STA_RONLY) \|
	282	(time_status & STA_RONLY);
	283
	284	if (txc->modes & ADJ_FREQUENCY) { /* p. 22 */
	285	if (txc->freq > MAXFREQ \|\| txc->freq < -MAXFREQ) {
	286	result = -EINVAL;
	287	goto leave;
	288	}
f4304ab2	289	time_freq = ((s64)txc->freq * NSEC_PER_USEC)
f4304ab2	290	>> (SHIFT_USEC - SHIFT_NSEC);
4c7ee8de	291	}
	292
	293	if (txc->modes & ADJ_MAXERROR) {
	294	if (txc->maxerror < 0 \|\| txc->maxerror >= NTP_PHASE_LIMIT) {
	295	result = -EINVAL;
	296	goto leave;
	297	}
	298	time_maxerror = txc->maxerror;
	299	}
	300
	301	if (txc->modes & ADJ_ESTERROR) {
	302	if (txc->esterror < 0 \|\| txc->esterror >= NTP_PHASE_LIMIT) {
	303	result = -EINVAL;
	304	goto leave;
	305	}
	306	time_esterror = txc->esterror;
	307	}
	308
	309	if (txc->modes & ADJ_TIMECONST) { /* p. 24 */
	310	if (txc->constant < 0) { /* NTP v4 uses values > 6 */
	311	result = -EINVAL;
	312	goto leave;
	313	}
f1992393	314	time_constant = min(txc->constant + 4, (long)MAXTC);
4c7ee8de	315	}
	316
	317	if (txc->modes & ADJ_OFFSET) { /* values checked earlier */
	318	if (txc->modes == ADJ_OFFSET_SINGLESHOT) {
	319	/* adjtime() is independent from ntp_adjtime() */
8f807f8d	320	time_adjust = txc->offset;
4c7ee8de	321	}
4c7ee8de	322	else if (time_status & STA_PLL) {
d62ac21a	323	time_offset = txc->offset * NSEC_PER_USEC;
4c7ee8de	324
	325	/*
	326	* Scale the phase adjustment and
	327	* clamp to the operating range.
	328	*/
d62ac21a	329	time_offset = min(time_offset, (s64)MAXPHASE * NSEC_PER_USEC);
d62ac21a	330	time_offset = max(time_offset, (s64)-MAXPHASE * NSEC_PER_USEC);
4c7ee8de	331
	332	/*
	333	* Select whether the frequency is to be controlled
	334	* and in which mode (PLL or FLL). Clamp to the operating
	335	* range. Ugly multiply/divide should be replaced someday.
	336	*/
	337
	338	if (time_status & STA_FREQHOLD \|\| time_reftime == 0)
	339	time_reftime = xtime.tv_sec;
	340	mtemp = xtime.tv_sec - time_reftime;
	341	time_reftime = xtime.tv_sec;
f1992393	342
d62ac21a	343	freq_adj = time_offset * mtemp;
f1992393 RZ	344	freq_adj = shift_right(freq_adj, time_constant * 2 +
	345	(SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
	346	if (mtemp >= MINSEC && (time_status & STA_FLL \|\| mtemp > MAXSEC)) {
d62ac21a	347	temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
f1992393 RZ	348	if (time_offset < 0) {
	349	temp64 = -temp64;
	350	do_div(temp64, mtemp);
	351	freq_adj -= temp64;
	352	} else {
	353	do_div(temp64, mtemp);
	354	freq_adj += temp64;
	355	}
4c7ee8de	356	}
04b617e7 RZ	357	freq_adj += time_freq;
	358	freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
	359	time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
d62ac21a	360	time_offset = div_long_long_rem_signed(time_offset,
	361	NTP_INTERVAL_FREQ,
	362	&rem);
	363	time_offset <<= SHIFT_UPDATE;
4c7ee8de	364	} /* STA_PLL */
4c7ee8de	365	} /* txc->modes & ADJ_OFFSET */
b0ee7556	366	if (txc->modes & ADJ_TICK)
4c7ee8de	367	tick_usec = txc->tick;
b0ee7556	368
dc6a43e4	369	if (txc->modes & (ADJ_TICK\|ADJ_FREQUENCY\|ADJ_OFFSET))
b0ee7556	370	ntp_update_frequency();
4c7ee8de	371	} /* txc->modes */
	372	leave: if ((time_status & (STA_UNSYNC\|STA_CLOCKERR)) != 0)
	373	result = TIME_ERROR;
	374
	375	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
d62ac21a	376	txc->offset = save_adjust;
3d3675cc	377	else
d62ac21a	378	txc->offset = ((long)shift_right(time_offset, SHIFT_UPDATE)) *
	379	NTP_INTERVAL_FREQ / 1000;
	380	txc->freq = (time_freq / NSEC_PER_USEC) <<
	381	(SHIFT_USEC - SHIFT_NSEC);
4c7ee8de	382	txc->maxerror = time_maxerror;
	383	txc->esterror = time_esterror;
	384	txc->status = time_status;
	385	txc->constant = time_constant;
70bc42f9	386	txc->precision = 1;
97eebe13	387	txc->tolerance = MAXFREQ;
4c7ee8de	388	txc->tick = tick_usec;
	389
	390	/* PPS is not implemented, so these are zero */
	391	txc->ppsfreq = 0;
	392	txc->jitter = 0;
	393	txc->shift = 0;
	394	txc->stabil = 0;
	395	txc->jitcnt = 0;
	396	txc->calcnt = 0;
	397	txc->errcnt = 0;
	398	txc->stbcnt = 0;
	399	write_sequnlock_irq(&xtime_lock);
	400	do_gettimeofday(&txc->time);
82644459	401	notify_cmos_timer();
4c7ee8de	402	return(result);
4c7ee8de	403	}