/* *  linux/kernel/time/timekeeping.c * *  Kernel timekeeping code and accessor functions * *  This code was moved from linux/kernel/timer.c. *  Please see that file for copyright and history logs. * */ #include <linux/timekeeper_internal.h>#include <linux/module.h>#include <linux/interrupt.h>#include <linux/percpu.h>#include <linux/init.h>#include <linux/mm.h>#include <linux/sched.h>#include <linux/syscore_ops.h>#include <linux/clocksource.h>#include <linux/jiffies.h>#include <linux/time.h>#include <linux/tick.h>#include <linux/stop_machine.h>#include <linux/pvclock_gtod.h>  static struct timekeeper timekeeper; /* flag for if timekeeping is suspended */int __read_mostly timekeeping_suspended; /* Flag for if there is a persistent clock on this platform */bool __read_mostly persistent_clock_exist = false; static inline void tk_normalize_xtime(struct timekeeper *tk){	while (tk->xtime_nsec >= ((u64)NSEC_PER_SEC << tk->shift)) {		tk->xtime_nsec -= (u64)NSEC_PER_SEC << tk->shift;		tk->xtime_sec++;	}} static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts){	tk->xtime_sec = ts->tv_sec;	tk->xtime_nsec = (u64)ts->tv_nsec << tk->shift;} static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts){	tk->xtime_sec += ts->tv_sec;	tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;	tk_normalize_xtime(tk);} static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm){	struct timespec tmp; 	/*	 * Verify consistency of: offset_real = -wall_to_monotonic	 * before modifying anything	 */	set_normalized_timespec(&tmp, -tk->wall_to_monotonic.tv_sec,					-tk->wall_to_monotonic.tv_nsec);	WARN_ON_ONCE(tk->offs_real.tv64 != timespec_to_ktime(tmp).tv64);	tk->wall_to_monotonic = wtm;	set_normalized_timespec(&tmp, -wtm.tv_sec, -wtm.tv_nsec);	tk->offs_real = timespec_to_ktime(tmp);} static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t){	/* Verify consistency before modifying */	WARN_ON_ONCE(tk->offs_boot.tv64 != timespec_to_ktime(tk->total_sleep_time).tv64); 	tk->total_sleep_time	= t;	tk->offs_boot		= timespec_to_ktime(t);} /** * timekeeper_setup_internals - Set up internals to use clocksource clock. * * @clock:		Pointer to clocksource. * * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment * pair and interval request. * * Unless you're the timekeeping code, you should not be using this! */static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock){	cycle_t interval;	u64 tmp, ntpinterval;	struct clocksource *old_clock; 	old_clock = tk->clock;	tk->clock = clock;	clock->cycle_last = clock->read(clock); 	/* Do the ns -> cycle conversion first, using original mult */	tmp = NTP_INTERVAL_LENGTH;	tmp <<= clock->shift;	ntpinterval = tmp;	tmp += clock->mult/2;	do_div(tmp, clock->mult);	if (tmp == 0)		tmp = 1; 	interval = (cycle_t) tmp;	tk->cycle_interval = interval; 	/* Go back from cycles -> shifted ns */	tk->xtime_interval = (u64) interval * clock->mult;	tk->xtime_remainder = ntpinterval - tk->xtime_interval;	tk->raw_interval =		((u64) interval * clock->mult) >> clock->shift; 	 /* if changing clocks, convert xtime_nsec shift units */	if (old_clock) {		int shift_change = clock->shift - old_clock->shift;		if (shift_change < 0)			tk->xtime_nsec >>= -shift_change;		else			tk->xtime_nsec <<= shift_change;	}	tk->shift = clock->shift; 	tk->ntp_error = 0;	tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift; 	/*	 * The timekeeper keeps its own mult values for the currently	 * active clocksource. These value will be adjusted via NTP	 * to counteract clock drifting.	 */	tk->mult = clock->mult;} /* Timekeeper helper functions. */ #ifdef CONFIG_ARCH_USES_GETTIMEOFFSETu32 (*arch_gettimeoffset)(void); u32 get_arch_timeoffset(void){	if (likely(arch_gettimeoffset))		return arch_gettimeoffset();	return 0;}#elsestatic inline u32 get_arch_timeoffset(void) { return 0; }#endif static inline s64 timekeeping_get_ns(struct timekeeper *tk){	cycle_t cycle_now, cycle_delta;	struct clocksource *clock;	s64 nsec; 	/* read clocksource: */	clock = tk->clock;	cycle_now = clock->read(clock); 	/* calculate the delta since the last update_wall_time: */	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; 	nsec = cycle_delta * tk->mult + tk->xtime_nsec;	nsec >>= tk->shift; 	/* If arch requires, add in get_arch_timeoffset() */	return nsec + get_arch_timeoffset();} static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk){	cycle_t cycle_now, cycle_delta;	struct clocksource *clock;	s64 nsec; 	/* read clocksource: */	clock = tk->clock;	cycle_now = clock->read(clock); 	/* calculate the delta since the last update_wall_time: */	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask; 	/* convert delta to nanoseconds. */	nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift); 	/* If arch requires, add in get_arch_timeoffset() */	return nsec + get_arch_timeoffset();} static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); static void update_pvclock_gtod(struct timekeeper *tk){	raw_notifier_call_chain(&pvclock_gtod_chain, 0, tk);} /** * pvclock_gtod_register_notifier - register a pvclock timedata update listener * * Must hold write on timekeeper.lock */int pvclock_gtod_register_notifier(struct notifier_block *nb){	struct timekeeper *tk = &timekeeper;	unsigned long flags;	int ret; 	write_seqlock_irqsave(&tk->lock, flags);	ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);	/* update timekeeping data */	update_pvclock_gtod(tk);	write_sequnlock_irqrestore(&tk->lock, flags); 	return ret;}EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); /** * pvclock_gtod_unregister_notifier - unregister a pvclock * timedata update listener * * Must hold write on timekeeper.lock */int pvclock_gtod_unregister_notifier(struct notifier_block *nb){	struct timekeeper *tk = &timekeeper;	unsigned long flags;	int ret; 	write_seqlock_irqsave(&tk->lock, flags);	ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);	write_sequnlock_irqrestore(&tk->lock, flags); 	return ret;}EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); /* must hold write on timekeeper.lock */static void timekeeping_update(struct timekeeper *tk, bool clearntp){	if (clearntp) {		tk->ntp_error = 0;		ntp_clear();	}	update_vsyscall(tk);	update_pvclock_gtod(tk);} /** * timekeeping_forward_now - update clock to the current time * * Forward the current clock to update its state since the last call to * update_wall_time(). This is useful before significant clock changes, * as it avoids having to deal with this time offset explicitly. */static void timekeeping_forward_now(struct timekeeper *tk){	cycle_t cycle_now, cycle_delta;	struct clocksource *clock;	s64 nsec; 	clock = tk->clock;	cycle_now = clock->read(clock);	cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;	clock->cycle_last = cycle_now; 	tk->xtime_nsec += cycle_delta * tk->mult; 	/* If arch requires, add in get_arch_timeoffset() */	tk->xtime_nsec += (u64)get_arch_timeoffset() << tk->shift; 	tk_normalize_xtime(tk); 	nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);	timespec_add_ns(&tk->raw_time, nsec);} /** * __getnstimeofday - Returns the time of day in a timespec. * @ts:		pointer to the timespec to be set * * Updates the time of day in the timespec. * Returns 0 on success, or -ve when suspended (timespec will be undefined). */int __getnstimeofday(struct timespec *ts){	struct timekeeper *tk = &timekeeper;	unsigned long seq;	s64 nsecs = 0; 	do {		seq = read_seqbegin(&tk->lock); 		ts->tv_sec = tk->xtime_sec;		nsecs = timekeeping_get_ns(tk); 	} while (read_seqretry(&tk->lock, seq)); 	ts->tv_nsec = 0;	timespec_add_ns(ts, nsecs); 	/*	 * Do not bail out early, in case there were callers still using	 * the value, even in the face of the WARN_ON.	 */	if (unlikely(timekeeping_suspended))		return -EAGAIN;	return 0;}EXPORT_SYMBOL(__getnstimeofday); /** * getnstimeofday - Returns the time of day in a timespec. * @ts:		pointer to the timespec to be set * * Returns the time of day in a timespec (WARN if suspended). */void getnstimeofday(struct timespec *ts){	WARN_ON(__getnstimeofday(ts));}EXPORT_SYMBOL(getnstimeofday); ktime_t ktime_get(void){	struct timekeeper *tk = &timekeeper;	unsigned int seq;	s64 secs, nsecs; 	WARN_ON(timekeeping_suspended); 	do {		seq = read_seqbegin(&tk->lock);		secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;		nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec; 	} while (read_seqretry(&tk->lock, seq));	/*	 * Use ktime_set/ktime_add_ns to create a proper ktime on	 * 32-bit architectures without CONFIG_KTIME_SCALAR.	 */	return ktime_add_ns(ktime_set(secs, 0), nsecs);}EXPORT_SYMBOL_GPL(ktime_get); /** * ktime_get_ts - get the monotonic clock in timespec format * @ts:		pointer to timespec variable * * The function calculates the monotonic clock from the realtime * clock and the wall_to_monotonic offset and stores the result * in normalized timespec format in the variable pointed to by @ts. */void ktime_get_ts(struct timespec *ts){	struct timekeeper *tk = &timekeeper;	struct timespec tomono;	s64 nsec;	unsigned int seq; 	WARN_ON(timekeeping_suspended); 	do {		seq = read_seqbegin(&tk->lock);		ts->tv_sec = tk->xtime_sec;		nsec = timekeeping_get_ns(tk);		tomono = tk->wall_to_monotonic; 	} while (read_seqretry(&tk->lock, seq)); 	ts->tv_sec += tomono.tv_sec;	ts->tv_nsec = 0;	timespec_add_ns(ts, nsec + tomono.tv_nsec);}EXPORT_SYMBOL_GPL(ktime_get_ts); #ifdef CONFIG_NTP_PPS /** * getnstime_raw_and_real - get day and raw monotonic time in timespec format * @ts_raw:	pointer to the timespec to be set to raw monotonic time * @ts_real:	pointer to the timespec to be set to the time of day * * This function reads both the time of day and raw monotonic time at the * same time atomically and stores the resulting timestamps in timespec * format. */void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real){	struct timekeeper *tk = &timekeeper;	unsigned long seq;	s64 nsecs_raw, nsecs_real; 	WARN_ON_ONCE(timekeeping_suspended); 	do {		seq = read_seqbegin(&tk->lock); 		*ts_raw = tk->raw_time;		ts_real->tv_sec = tk->xtime_sec;		ts_real->tv_nsec = 0; 		nsecs_raw = timekeeping_get_ns_raw(tk);		nsecs_real = timekeeping_get_ns(tk); 	} while (read_seqretry(&tk->lock, seq)); 	timespec_add_ns(ts_raw, nsecs_raw);	timespec_add_ns(ts_real, nsecs_real);}EXPORT_SYMBOL(getnstime_raw_and_real); #endif /* CONFIG_NTP_PPS */ /** * do_gettimeofday - Returns the time of day in a timeval * @tv:		pointer to the timeval to be set * * NOTE: Users should be converted to using getnstimeofday() */void do_gettimeofday(struct timeval *tv){	struct timespec now; 	getnstimeofday(&now);	tv->tv_sec = now.tv_sec;	tv->tv_usec = now.tv_nsec/1000;}EXPORT_SYMBOL(do_gettimeofday); /** * do_settimeofday - Sets the time of day * @tv:		pointer to the timespec variable containing the new time * * Sets the time of day to the new time and update NTP and notify hrtimers */int do_settimeofday(const struct timespec *tv){	struct timekeeper *tk = &timekeeper;	struct timespec ts_delta, xt;	unsigned long flags; 	if (!timespec_valid_strict(tv))		return -EINVAL; 	write_seqlock_irqsave(&tk->lock, flags); 	timekeeping_forward_now(tk); 	xt = tk_xtime(tk);	ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;	ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec; 	tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, ts_delta)); 	tk_set_xtime(tk, tv); 	timekeeping_update(tk, true); 	write_sequnlock_irqrestore(&tk->lock, flags); 	/* signal hrtimers about time change */	clock_was_set(); 	return 0;}EXPORT_SYMBOL(do_settimeofday); /** * timekeeping_inject_offset - Adds or subtracts from the current time. * @tv:		pointer to the timespec variable containing the offset * * Adds or subtracts an offset value from the current time. */int timekeeping_inject_offset(struct timespec *ts){	struct timekeeper *tk = &timekeeper;	unsigned long flags;	struct timespec tmp;	int ret = 0; 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)		return -EINVAL; 	write_seqlock_irqsave(&tk->lock, flags); 	timekeeping_forward_now(tk); 	/* Make sure the proposed value is valid */	tmp = timespec_add(tk_xtime(tk),  *ts);	if (!timespec_valid_strict(&tmp)) {		ret = -EINVAL;		goto error;	} 

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