Initial import

1 files changed, 2072 insertions, 0 deletions

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
new file mode 100644
index 000000000..946acb721
--- /dev/null
+++ b/kernel/time/timekeeping.c
@@ -0,0 +1,2072 @@
+/*
+ *  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>
+#include <linux/compiler.h>
+
+#include "tick-internal.h"
+#include "ntp_internal.h"
+#include "timekeeping_internal.h"
+
+#define TK_CLEAR_NTP		(1 << 0)
+#define TK_MIRROR		(1 << 1)
+#define TK_CLOCK_WAS_SET	(1 << 2)
+
+/*
+ * The most important data for readout fits into a single 64 byte
+ * cache line.
+ */
+static struct {
+	seqcount_t		seq;
+	struct timekeeper	timekeeper;
+} tk_core ____cacheline_aligned;
+
+static DEFINE_RAW_SPINLOCK(timekeeper_lock);
+static struct timekeeper shadow_timekeeper;
+
+/**
+ * struct tk_fast - NMI safe timekeeper
+ * @seq:	Sequence counter for protecting updates. The lowest bit
+ *		is the index for the tk_read_base array
+ * @base:	tk_read_base array. Access is indexed by the lowest bit of
+ *		@seq.
+ *
+ * See @update_fast_timekeeper() below.
+ */
+struct tk_fast {
+	seqcount_t		seq;
+	struct tk_read_base	base[2];
+};
+
+static struct tk_fast tk_fast_mono ____cacheline_aligned;
+static struct tk_fast tk_fast_raw  ____cacheline_aligned;
+
+/* flag for if timekeeping is suspended */
+int __read_mostly timekeeping_suspended;
+
+static inline void tk_normalize_xtime(struct timekeeper *tk)
+{
+	while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
+		tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
+		tk->xtime_sec++;
+	}
+}
+
+static inline struct timespec64 tk_xtime(struct timekeeper *tk)
+{
+	struct timespec64 ts;
+
+	ts.tv_sec = tk->xtime_sec;
+	ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
+	return ts;
+}
+
+static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
+{
+	tk->xtime_sec = ts->tv_sec;
+	tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
+}
+
+static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
+{
+	tk->xtime_sec += ts->tv_sec;
+	tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
+	tk_normalize_xtime(tk);
+}
+
+static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
+{
+	struct timespec64 tmp;
+
+	/*
+	 * Verify consistency of: offset_real = -wall_to_monotonic
+	 * before modifying anything
+	 */
+	set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
+					-tk->wall_to_monotonic.tv_nsec);
+	WARN_ON_ONCE(tk->offs_real.tv64 != timespec64_to_ktime(tmp).tv64);
+	tk->wall_to_monotonic = wtm;
+	set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
+	tk->offs_real = timespec64_to_ktime(tmp);
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
+}
+
+static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
+{
+	tk->offs_boot = ktime_add(tk->offs_boot, delta);
+}
+
+#ifdef CONFIG_DEBUG_TIMEKEEPING
+#define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
+/*
+ * These simple flag variables are managed
+ * without locks, which is racy, but ok since
+ * we don't really care about being super
+ * precise about how many events were seen,
+ * just that a problem was observed.
+ */
+static int timekeeping_underflow_seen;
+static int timekeeping_overflow_seen;
+
+/* last_warning is only modified under the timekeeping lock */
+static long timekeeping_last_warning;
+
+static void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
+{
+
+	cycle_t max_cycles = tk->tkr_mono.clock->max_cycles;
+	const char *name = tk->tkr_mono.clock->name;
+
+	if (offset > max_cycles) {
+		printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
+				offset, name, max_cycles);
+		printk_deferred("         timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
+	} else {
+		if (offset > (max_cycles >> 1)) {
+			printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the the '%s' clock's 50%% safety margin (%lld)\n",
+					offset, name, max_cycles >> 1);
+			printk_deferred("      timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
+		}
+	}
+
+	if (timekeeping_underflow_seen) {
+		if (jiffies - timekeeping_last_warning > WARNING_FREQ) {
+			printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
+			printk_deferred("         Please report this, consider using a different clocksource, if possible.\n");
+			printk_deferred("         Your kernel is probably still fine.\n");
+			timekeeping_last_warning = jiffies;
+		}
+		timekeeping_underflow_seen = 0;
+	}
+
+	if (timekeeping_overflow_seen) {
+		if (jiffies - timekeeping_last_warning > WARNING_FREQ) {
+			printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
+			printk_deferred("         Please report this, consider using a different clocksource, if possible.\n");
+			printk_deferred("         Your kernel is probably still fine.\n");
+			timekeeping_last_warning = jiffies;
+		}
+		timekeeping_overflow_seen = 0;
+	}
+}
+
+static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
+{
+	cycle_t now, last, mask, max, delta;
+	unsigned int seq;
+
+	/*
+	 * Since we're called holding a seqlock, the data may shift
+	 * under us while we're doing the calculation. This can cause
+	 * false positives, since we'd note a problem but throw the
+	 * results away. So nest another seqlock here to atomically
+	 * grab the points we are checking with.
+	 */
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		now = tkr->read(tkr->clock);
+		last = tkr->cycle_last;
+		mask = tkr->mask;
+		max = tkr->clock->max_cycles;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	delta = clocksource_delta(now, last, mask);
+
+	/*
+	 * Try to catch underflows by checking if we are seeing small
+	 * mask-relative negative values.
+	 */
+	if (unlikely((~delta & mask) < (mask >> 3))) {
+		timekeeping_underflow_seen = 1;
+		delta = 0;
+	}
+
+	/* Cap delta value to the max_cycles values to avoid mult overflows */
+	if (unlikely(delta > max)) {
+		timekeeping_overflow_seen = 1;
+		delta = tkr->clock->max_cycles;
+	}
+
+	return delta;
+}
+#else
+static inline void timekeeping_check_update(struct timekeeper *tk, cycle_t offset)
+{
+}
+static inline cycle_t timekeeping_get_delta(struct tk_read_base *tkr)
+{
+	cycle_t cycle_now, delta;
+
+	/* read clocksource */
+	cycle_now = tkr->read(tkr->clock);
+
+	/* calculate the delta since the last update_wall_time */
+	delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
+
+	return delta;
+}
+#endif
+
+/**
+ * tk_setup_internals - Set up internals to use clocksource clock.
+ *
+ * @tk:		The target timekeeper to setup.
+ * @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->tkr_mono.clock;
+	tk->tkr_mono.clock = clock;
+	tk->tkr_mono.read = clock->read;
+	tk->tkr_mono.mask = clock->mask;
+	tk->tkr_mono.cycle_last = tk->tkr_mono.read(clock);
+
+	tk->tkr_raw.clock = clock;
+	tk->tkr_raw.read = clock->read;
+	tk->tkr_raw.mask = clock->mask;
+	tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
+
+	/* 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->tkr_mono.xtime_nsec >>= -shift_change;
+		else
+			tk->tkr_mono.xtime_nsec <<= shift_change;
+	}
+	tk->tkr_raw.xtime_nsec = 0;
+
+	tk->tkr_mono.shift = clock->shift;
+	tk->tkr_raw.shift = clock->shift;
+
+	tk->ntp_error = 0;
+	tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+	tk->ntp_tick = ntpinterval << tk->ntp_error_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->tkr_mono.mult = clock->mult;
+	tk->tkr_raw.mult = clock->mult;
+	tk->ntp_err_mult = 0;
+}
+
+/* Timekeeper helper functions. */
+
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
+static u32 default_arch_gettimeoffset(void) { return 0; }
+u32 (*arch_gettimeoffset)(void) = default_arch_gettimeoffset;
+#else
+static inline u32 arch_gettimeoffset(void) { return 0; }
+#endif
+
+static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
+{
+	cycle_t delta;
+	s64 nsec;
+
+	delta = timekeeping_get_delta(tkr);
+
+	nsec = delta * tkr->mult + tkr->xtime_nsec;
+	nsec >>= tkr->shift;
+
+	/* If arch requires, add in get_arch_timeoffset() */
+	return nsec + arch_gettimeoffset();
+}
+
+/**
+ * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
+ * @tkr: Timekeeping readout base from which we take the update
+ *
+ * We want to use this from any context including NMI and tracing /
+ * instrumenting the timekeeping code itself.
+ *
+ * So we handle this differently than the other timekeeping accessor
+ * functions which retry when the sequence count has changed. The
+ * update side does:
+ *
+ * smp_wmb();	<- Ensure that the last base[1] update is visible
+ * tkf->seq++;
+ * smp_wmb();	<- Ensure that the seqcount update is visible
+ * update(tkf->base[0], tkr);
+ * smp_wmb();	<- Ensure that the base[0] update is visible
+ * tkf->seq++;
+ * smp_wmb();	<- Ensure that the seqcount update is visible
+ * update(tkf->base[1], tkr);
+ *
+ * The reader side does:
+ *
+ * do {
+ *	seq = tkf->seq;
+ *	smp_rmb();
+ *	idx = seq & 0x01;
+ *	now = now(tkf->base[idx]);
+ *	smp_rmb();
+ * } while (seq != tkf->seq)
+ *
+ * As long as we update base[0] readers are forced off to
+ * base[1]. Once base[0] is updated readers are redirected to base[0]
+ * and the base[1] update takes place.
+ *
+ * So if a NMI hits the update of base[0] then it will use base[1]
+ * which is still consistent. In the worst case this can result is a
+ * slightly wrong timestamp (a few nanoseconds). See
+ * @ktime_get_mono_fast_ns.
+ */
+static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
+{
+	struct tk_read_base *base = tkf->base;
+
+	/* Force readers off to base[1] */
+	raw_write_seqcount_latch(&tkf->seq);
+
+	/* Update base[0] */
+	memcpy(base, tkr, sizeof(*base));
+
+	/* Force readers back to base[0] */
+	raw_write_seqcount_latch(&tkf->seq);
+
+	/* Update base[1] */
+	memcpy(base + 1, base, sizeof(*base));
+}
+
+/**
+ * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
+ *
+ * This timestamp is not guaranteed to be monotonic across an update.
+ * The timestamp is calculated by:
+ *
+ *	now = base_mono + clock_delta * slope
+ *
+ * So if the update lowers the slope, readers who are forced to the
+ * not yet updated second array are still using the old steeper slope.
+ *
+ * tmono
+ * ^
+ * |    o  n
+ * |   o n
+ * |  u
+ * | o
+ * |o
+ * |12345678---> reader order
+ *
+ * o = old slope
+ * u = update
+ * n = new slope
+ *
+ * So reader 6 will observe time going backwards versus reader 5.
+ *
+ * While other CPUs are likely to be able observe that, the only way
+ * for a CPU local observation is when an NMI hits in the middle of
+ * the update. Timestamps taken from that NMI context might be ahead
+ * of the following timestamps. Callers need to be aware of that and
+ * deal with it.
+ */
+static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
+{
+	struct tk_read_base *tkr;
+	unsigned int seq;
+	u64 now;
+
+	do {
+		seq = raw_read_seqcount(&tkf->seq);
+		tkr = tkf->base + (seq & 0x01);
+		now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr);
+	} while (read_seqcount_retry(&tkf->seq, seq));
+
+	return now;
+}
+
+u64 ktime_get_mono_fast_ns(void)
+{
+	return __ktime_get_fast_ns(&tk_fast_mono);
+}
+EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
+
+u64 ktime_get_raw_fast_ns(void)
+{
+	return __ktime_get_fast_ns(&tk_fast_raw);
+}
+EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
+
+/* Suspend-time cycles value for halted fast timekeeper. */
+static cycle_t cycles_at_suspend;
+
+static cycle_t dummy_clock_read(struct clocksource *cs)
+{
+	return cycles_at_suspend;
+}
+
+/**
+ * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
+ * @tk: Timekeeper to snapshot.
+ *
+ * It generally is unsafe to access the clocksource after timekeeping has been
+ * suspended, so take a snapshot of the readout base of @tk and use it as the
+ * fast timekeeper's readout base while suspended.  It will return the same
+ * number of cycles every time until timekeeping is resumed at which time the
+ * proper readout base for the fast timekeeper will be restored automatically.
+ */
+static void halt_fast_timekeeper(struct timekeeper *tk)
+{
+	static struct tk_read_base tkr_dummy;
+	struct tk_read_base *tkr = &tk->tkr_mono;
+
+	memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
+	cycles_at_suspend = tkr->read(tkr->clock);
+	tkr_dummy.read = dummy_clock_read;
+	update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
+
+	tkr = &tk->tkr_raw;
+	memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
+	tkr_dummy.read = dummy_clock_read;
+	update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
+}
+
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
+
+static inline void update_vsyscall(struct timekeeper *tk)
+{
+	struct timespec xt, wm;
+
+	xt = timespec64_to_timespec(tk_xtime(tk));
+	wm = timespec64_to_timespec(tk->wall_to_monotonic);
+	update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
+			    tk->tkr_mono.cycle_last);
+}
+
+static inline void old_vsyscall_fixup(struct timekeeper *tk)
+{
+	s64 remainder;
+
+	/*
+	* Store only full nanoseconds into xtime_nsec after rounding
+	* it up and add the remainder to the error difference.
+	* XXX - This is necessary to avoid small 1ns inconsistnecies caused
+	* by truncating the remainder in vsyscalls. However, it causes
+	* additional work to be done in timekeeping_adjust(). Once
+	* the vsyscall implementations are converted to use xtime_nsec
+	* (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
+	* users are removed, this can be killed.
+	*/
+	remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
+	tk->tkr_mono.xtime_nsec -= remainder;
+	tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
+	tk->ntp_error += remainder << tk->ntp_error_shift;
+	tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
+}
+#else
+#define old_vsyscall_fixup(tk)
+#endif
+
+static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
+
+static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
+{
+	raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
+}
+
+/**
+ * pvclock_gtod_register_notifier - register a pvclock timedata update listener
+ */
+int pvclock_gtod_register_notifier(struct notifier_block *nb)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
+	update_pvclock_gtod(tk, true);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
+
+/**
+ * pvclock_gtod_unregister_notifier - unregister a pvclock
+ * timedata update listener
+ */
+int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
+{
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
+
+/*
+ * Update the ktime_t based scalar nsec members of the timekeeper
+ */
+static inline void tk_update_ktime_data(struct timekeeper *tk)
+{
+	u64 seconds;
+	u32 nsec;
+
+	/*
+	 * The xtime based monotonic readout is:
+	 *	nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
+	 * The ktime based monotonic readout is:
+	 *	nsec = base_mono + now();
+	 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
+	 */
+	seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
+	nsec = (u32) tk->wall_to_monotonic.tv_nsec;
+	tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
+
+	/* Update the monotonic raw base */
+	tk->tkr_raw.base = timespec64_to_ktime(tk->raw_time);
+
+	/*
+	 * The sum of the nanoseconds portions of xtime and
+	 * wall_to_monotonic can be greater/equal one second. Take
+	 * this into account before updating tk->ktime_sec.
+	 */
+	nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
+	if (nsec >= NSEC_PER_SEC)
+		seconds++;
+	tk->ktime_sec = seconds;
+}
+
+/* must hold timekeeper_lock */
+static void timekeeping_update(struct timekeeper *tk, unsigned int action)
+{
+	if (action & TK_CLEAR_NTP) {
+		tk->ntp_error = 0;
+		ntp_clear();
+	}
+
+	tk_update_ktime_data(tk);
+
+	update_vsyscall(tk);
+	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
+
+	if (action & TK_MIRROR)
+		memcpy(&shadow_timekeeper, &tk_core.timekeeper,
+		       sizeof(tk_core.timekeeper));
+
+	update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
+	update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
+}
+
+/**
+ * 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)
+{
+	struct clocksource *clock = tk->tkr_mono.clock;
+	cycle_t cycle_now, delta;
+	s64 nsec;
+
+	cycle_now = tk->tkr_mono.read(clock);
+	delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
+	tk->tkr_mono.cycle_last = cycle_now;
+	tk->tkr_raw.cycle_last  = cycle_now;
+
+	tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
+
+	/* If arch requires, add in get_arch_timeoffset() */
+	tk->tkr_mono.xtime_nsec += (u64)arch_gettimeoffset() << tk->tkr_mono.shift;
+
+	tk_normalize_xtime(tk);
+
+	nsec = clocksource_cyc2ns(delta, tk->tkr_raw.mult, tk->tkr_raw.shift);
+	timespec64_add_ns(&tk->raw_time, nsec);
+}
+
+/**
+ * __getnstimeofday64 - Returns the time of day in a timespec64.
+ * @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 __getnstimeofday64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long seq;
+	s64 nsecs = 0;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		ts->tv_sec = tk->xtime_sec;
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	ts->tv_nsec = 0;
+	timespec64_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(__getnstimeofday64);
+
+/**
+ * getnstimeofday64 - Returns the time of day in a timespec64.
+ * @ts:		pointer to the timespec64 to be set
+ *
+ * Returns the time of day in a timespec64 (WARN if suspended).
+ */
+void getnstimeofday64(struct timespec64 *ts)
+{
+	WARN_ON(__getnstimeofday64(ts));
+}
+EXPORT_SYMBOL(getnstimeofday64);
+
+ktime_t ktime_get(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	s64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = tk->tkr_mono.base;
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get);
+
+static ktime_t *offsets[TK_OFFS_MAX] = {
+	[TK_OFFS_REAL]	= &tk_core.timekeeper.offs_real,
+	[TK_OFFS_BOOT]	= &tk_core.timekeeper.offs_boot,
+	[TK_OFFS_TAI]	= &tk_core.timekeeper.offs_tai,
+};
+
+ktime_t ktime_get_with_offset(enum tk_offsets offs)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base, *offset = offsets[offs];
+	s64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = ktime_add(tk->tkr_mono.base, *offset);
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+
+}
+EXPORT_SYMBOL_GPL(ktime_get_with_offset);
+
+/**
+ * ktime_mono_to_any() - convert mononotic time to any other time
+ * @tmono:	time to convert.
+ * @offs:	which offset to use
+ */
+ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
+{
+	ktime_t *offset = offsets[offs];
+	unsigned long seq;
+	ktime_t tconv;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		tconv = ktime_add(tmono, *offset);
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return tconv;
+}
+EXPORT_SYMBOL_GPL(ktime_mono_to_any);
+
+/**
+ * ktime_get_raw - Returns the raw monotonic time in ktime_t format
+ */
+ktime_t ktime_get_raw(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	s64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = tk->tkr_raw.base;
+		nsecs = timekeeping_get_ns(&tk->tkr_raw);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get_raw);
+
+/**
+ * ktime_get_ts64 - get the monotonic clock in timespec64 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 timespec64 format in the variable pointed to by @ts.
+ */
+void ktime_get_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 tomono;
+	s64 nsec;
+	unsigned int seq;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		ts->tv_sec = tk->xtime_sec;
+		nsec = timekeeping_get_ns(&tk->tkr_mono);
+		tomono = tk->wall_to_monotonic;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	ts->tv_sec += tomono.tv_sec;
+	ts->tv_nsec = 0;
+	timespec64_add_ns(ts, nsec + tomono.tv_nsec);
+}
+EXPORT_SYMBOL_GPL(ktime_get_ts64);
+
+/**
+ * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
+ *
+ * Returns the seconds portion of CLOCK_MONOTONIC with a single non
+ * serialized read. tk->ktime_sec is of type 'unsigned long' so this
+ * works on both 32 and 64 bit systems. On 32 bit systems the readout
+ * covers ~136 years of uptime which should be enough to prevent
+ * premature wrap arounds.
+ */
+time64_t ktime_get_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	WARN_ON(timekeeping_suspended);
+	return tk->ktime_sec;
+}
+EXPORT_SYMBOL_GPL(ktime_get_seconds);
+
+/**
+ * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
+ *
+ * Returns the wall clock seconds since 1970. This replaces the
+ * get_seconds() interface which is not y2038 safe on 32bit systems.
+ *
+ * For 64bit systems the fast access to tk->xtime_sec is preserved. On
+ * 32bit systems the access must be protected with the sequence
+ * counter to provide "atomic" access to the 64bit tk->xtime_sec
+ * value.
+ */
+time64_t ktime_get_real_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	time64_t seconds;
+	unsigned int seq;
+
+	if (IS_ENABLED(CONFIG_64BIT))
+		return tk->xtime_sec;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		seconds = tk->xtime_sec;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return seconds;
+}
+EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
+
+#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 = &tk_core.timekeeper;
+	unsigned long seq;
+	s64 nsecs_raw, nsecs_real;
+
+	WARN_ON_ONCE(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		*ts_raw = timespec64_to_timespec(tk->raw_time);
+		ts_real->tv_sec = tk->xtime_sec;
+		ts_real->tv_nsec = 0;
+
+		nsecs_raw  = timekeeping_get_ns(&tk->tkr_raw);
+		nsecs_real = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, 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 timespec64 now;
+
+	getnstimeofday64(&now);
+	tv->tv_sec = now.tv_sec;
+	tv->tv_usec = now.tv_nsec/1000;
+}
+EXPORT_SYMBOL(do_gettimeofday);
+
+/**
+ * do_settimeofday64 - Sets the time of day.
+ * @ts:     pointer to the timespec64 variable containing the new time
+ *
+ * Sets the time of day to the new time and update NTP and notify hrtimers
+ */
+int do_settimeofday64(const struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 ts_delta, xt;
+	unsigned long flags;
+
+	if (!timespec64_valid_strict(ts))
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	xt = tk_xtime(tk);
+	ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
+	ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
+
+	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
+
+	tk_set_xtime(tk, ts);
+
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* signal hrtimers about time change */
+	clock_was_set();
+
+	return 0;
+}
+EXPORT_SYMBOL(do_settimeofday64);
+
+/**
+ * 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 = &tk_core.timekeeper;
+	unsigned long flags;
+	struct timespec64 ts64, tmp;
+	int ret = 0;
+
+	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
+		return -EINVAL;
+
+	ts64 = timespec_to_timespec64(*ts);
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	/* Make sure the proposed value is valid */
+	tmp = timespec64_add(tk_xtime(tk),  ts64);
+	if (!timespec64_valid_strict(&tmp)) {
+		ret = -EINVAL;
+		goto error;
+	}
+
+	tk_xtime_add(tk, &ts64);
+	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts64));
+
+error: /* even if we error out, we forwarded the time, so call update */
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* signal hrtimers about time change */
+	clock_was_set();
+
+	return ret;
+}
+EXPORT_SYMBOL(timekeeping_inject_offset);
+
+
+/**
+ * timekeeping_get_tai_offset - Returns current TAI offset from UTC
+ *
+ */
+s32 timekeeping_get_tai_offset(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	s32 ret;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		ret = tk->tai_offset;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ret;
+}
+
+/**
+ * __timekeeping_set_tai_offset - Lock free worker function
+ *
+ */
+static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
+{
+	tk->tai_offset = tai_offset;
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
+}
+
+/**
+ * timekeeping_set_tai_offset - Sets the current TAI offset from UTC
+ *
+ */
+void timekeeping_set_tai_offset(s32 tai_offset)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+	__timekeeping_set_tai_offset(tk, tai_offset);
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+	clock_was_set();
+}
+
+/**
+ * change_clocksource - Swaps clocksources if a new one is available
+ *
+ * Accumulates current time interval and initializes new clocksource
+ */
+static int change_clocksource(void *data)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct clocksource *new, *old;
+	unsigned long flags;
+
+	new = (struct clocksource *) data;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+	/*
+	 * If the cs is in module, get a module reference. Succeeds
+	 * for built-in code (owner == NULL) as well.
+	 */
+	if (try_module_get(new->owner)) {
+		if (!new->enable || new->enable(new) == 0) {
+			old = tk->tkr_mono.clock;
+			tk_setup_internals(tk, new);
+			if (old->disable)
+				old->disable(old);
+			module_put(old->owner);
+		} else {
+			module_put(new->owner);
+		}
+	}
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	return 0;
+}
+
+/**
+ * timekeeping_notify - Install a new clock source
+ * @clock:		pointer to the clock source
+ *
+ * This function is called from clocksource.c after a new, better clock
+ * source has been registered. The caller holds the clocksource_mutex.
+ */
+int timekeeping_notify(struct clocksource *clock)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	if (tk->tkr_mono.clock == clock)
+		return 0;
+	stop_machine(change_clocksource, clock, NULL);
+	tick_clock_notify();
+	return tk->tkr_mono.clock == clock ? 0 : -1;
+}
+
+/**
+ * getrawmonotonic64 - Returns the raw monotonic time in a timespec
+ * @ts:		pointer to the timespec64 to be set
+ *
+ * Returns the raw monotonic time (completely un-modified by ntp)
+ */
+void getrawmonotonic64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 ts64;
+	unsigned long seq;
+	s64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		nsecs = timekeeping_get_ns(&tk->tkr_raw);
+		ts64 = tk->raw_time;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	timespec64_add_ns(&ts64, nsecs);
+	*ts = ts64;
+}
+EXPORT_SYMBOL(getrawmonotonic64);
+
+
+/**
+ * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
+ */
+int timekeeping_valid_for_hres(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long seq;
+	int ret;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ret;
+}
+
+/**
+ * timekeeping_max_deferment - Returns max time the clocksource can be deferred
+ */
+u64 timekeeping_max_deferment(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long seq;
+	u64 ret;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		ret = tk->tkr_mono.clock->max_idle_ns;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ret;
+}
+
+/**
+ * read_persistent_clock -  Return time from the persistent clock.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Reads the time from the battery backed persistent clock.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
+ *
+ *  XXX - Do be sure to remove it once all arches implement it.
+ */
+void __weak read_persistent_clock(struct timespec *ts)
+{
+	ts->tv_sec = 0;
+	ts->tv_nsec = 0;
+}
+
+void __weak read_persistent_clock64(struct timespec64 *ts64)
+{
+	struct timespec ts;
+
+	read_persistent_clock(&ts);
+	*ts64 = timespec_to_timespec64(ts);
+}
+
+/**
+ * read_boot_clock -  Return time of the system start.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Function to read the exact time the system has been started.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
+ *
+ *  XXX - Do be sure to remove it once all arches implement it.
+ */
+void __weak read_boot_clock(struct timespec *ts)
+{
+	ts->tv_sec = 0;
+	ts->tv_nsec = 0;
+}
+
+void __weak read_boot_clock64(struct timespec64 *ts64)
+{
+	struct timespec ts;
+
+	read_boot_clock(&ts);
+	*ts64 = timespec_to_timespec64(ts);
+}
+
+/* Flag for if timekeeping_resume() has injected sleeptime */
+static bool sleeptime_injected;
+
+/* Flag for if there is a persistent clock on this platform */
+static bool persistent_clock_exists;
+
+/*
+ * timekeeping_init - Initializes the clocksource and common timekeeping values
+ */
+void __init timekeeping_init(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct clocksource *clock;
+	unsigned long flags;
+	struct timespec64 now, boot, tmp;
+
+	read_persistent_clock64(&now);
+	if (!timespec64_valid_strict(&now)) {
+		pr_warn("WARNING: Persistent clock returned invalid value!\n"
+			"         Check your CMOS/BIOS settings.\n");
+		now.tv_sec = 0;
+		now.tv_nsec = 0;
+	} else if (now.tv_sec || now.tv_nsec)
+		persistent_clock_exists = true;
+
+	read_boot_clock64(&boot);
+	if (!timespec64_valid_strict(&boot)) {
+		pr_warn("WARNING: Boot clock returned invalid value!\n"
+			"         Check your CMOS/BIOS settings.\n");
+		boot.tv_sec = 0;
+		boot.tv_nsec = 0;
+	}
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+	ntp_init();
+
+	clock = clocksource_default_clock();
+	if (clock->enable)
+		clock->enable(clock);
+	tk_setup_internals(tk, clock);
+
+	tk_set_xtime(tk, &now);
+	tk->raw_time.tv_sec = 0;
+	tk->raw_time.tv_nsec = 0;
+	if (boot.tv_sec == 0 && boot.tv_nsec == 0)
+		boot = tk_xtime(tk);
+
+	set_normalized_timespec64(&tmp, -boot.tv_sec, -boot.tv_nsec);
+	tk_set_wall_to_mono(tk, tmp);
+
+	timekeeping_update(tk, TK_MIRROR);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+}
+
+/* time in seconds when suspend began for persistent clock */
+static struct timespec64 timekeeping_suspend_time;
+
+/**
+ * __timekeeping_inject_sleeptime - Internal function to add sleep interval
+ * @delta: pointer to a timespec delta value
+ *
+ * Takes a timespec offset measuring a suspend interval and properly
+ * adds the sleep offset to the timekeeping variables.
+ */
+static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
+					   struct timespec64 *delta)
+{
+	if (!timespec64_valid_strict(delta)) {
+		printk_deferred(KERN_WARNING
+				"__timekeeping_inject_sleeptime: Invalid "
+				"sleep delta value!\n");
+		return;
+	}
+	tk_xtime_add(tk, delta);
+	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
+	tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
+	tk_debug_account_sleep_time(delta);
+}
+
+#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
+/**
+ * We have three kinds of time sources to use for sleep time
+ * injection, the preference order is:
+ * 1) non-stop clocksource
+ * 2) persistent clock (ie: RTC accessible when irqs are off)
+ * 3) RTC
+ *
+ * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
+ * If system has neither 1) nor 2), 3) will be used finally.
+ *
+ *
+ * If timekeeping has injected sleeptime via either 1) or 2),
+ * 3) becomes needless, so in this case we don't need to call
+ * rtc_resume(), and this is what timekeeping_rtc_skipresume()
+ * means.
+ */
+bool timekeeping_rtc_skipresume(void)
+{
+	return sleeptime_injected;
+}
+
+/**
+ * 1) can be determined whether to use or not only when doing
+ * timekeeping_resume() which is invoked after rtc_suspend(),
+ * so we can't skip rtc_suspend() surely if system has 1).
+ *
+ * But if system has 2), 2) will definitely be used, so in this
+ * case we don't need to call rtc_suspend(), and this is what
+ * timekeeping_rtc_skipsuspend() means.
+ */
+bool timekeeping_rtc_skipsuspend(void)
+{
+	return persistent_clock_exists;
+}
+
+/**
+ * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
+ * @delta: pointer to a timespec64 delta value
+ *
+ * This hook is for architectures that cannot support read_persistent_clock64
+ * because their RTC/persistent clock is only accessible when irqs are enabled.
+ * and also don't have an effective nonstop clocksource.
+ *
+ * This function should only be called by rtc_resume(), and allows
+ * a suspend offset to be injected into the timekeeping values.
+ */
+void timekeeping_inject_sleeptime64(struct timespec64 *delta)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	__timekeeping_inject_sleeptime(tk, delta);
+
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* signal hrtimers about time change */
+	clock_was_set();
+}
+#endif
+
+/**
+ * timekeeping_resume - Resumes the generic timekeeping subsystem.
+ */
+void timekeeping_resume(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct clocksource *clock = tk->tkr_mono.clock;
+	unsigned long flags;
+	struct timespec64 ts_new, ts_delta;
+	cycle_t cycle_now, cycle_delta;
+
+	sleeptime_injected = false;
+	read_persistent_clock64(&ts_new);
+
+	clockevents_resume();
+	clocksource_resume();
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	/*
+	 * After system resumes, we need to calculate the suspended time and
+	 * compensate it for the OS time. There are 3 sources that could be
+	 * used: Nonstop clocksource during suspend, persistent clock and rtc
+	 * device.
+	 *
+	 * One specific platform may have 1 or 2 or all of them, and the
+	 * preference will be:
+	 *	suspend-nonstop clocksource -> persistent clock -> rtc
+	 * The less preferred source will only be tried if there is no better
+	 * usable source. The rtc part is handled separately in rtc core code.
+	 */
+	cycle_now = tk->tkr_mono.read(clock);
+	if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
+		cycle_now > tk->tkr_mono.cycle_last) {
+		u64 num, max = ULLONG_MAX;
+		u32 mult = clock->mult;
+		u32 shift = clock->shift;
+		s64 nsec = 0;
+
+		cycle_delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last,
+						tk->tkr_mono.mask);
+
+		/*
+		 * "cycle_delta * mutl" may cause 64 bits overflow, if the
+		 * suspended time is too long. In that case we need do the
+		 * 64 bits math carefully
+		 */
+		do_div(max, mult);
+		if (cycle_delta > max) {
+			num = div64_u64(cycle_delta, max);
+			nsec = (((u64) max * mult) >> shift) * num;
+			cycle_delta -= num * max;
+		}
+		nsec += ((u64) cycle_delta * mult) >> shift;
+
+		ts_delta = ns_to_timespec64(nsec);
+		sleeptime_injected = true;
+	} else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
+		ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
+		sleeptime_injected = true;
+	}
+
+	if (sleeptime_injected)
+		__timekeeping_inject_sleeptime(tk, &ts_delta);
+
+	/* Re-base the last cycle value */
+	tk->tkr_mono.cycle_last = cycle_now;
+	tk->tkr_raw.cycle_last  = cycle_now;
+
+	tk->ntp_error = 0;
+	timekeeping_suspended = 0;
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	touch_softlockup_watchdog();
+
+	tick_resume();
+	hrtimers_resume();
+}
+
+int timekeeping_suspend(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+	struct timespec64		delta, delta_delta;
+	static struct timespec64	old_delta;
+
+	read_persistent_clock64(&timekeeping_suspend_time);
+
+	/*
+	 * On some systems the persistent_clock can not be detected at
+	 * timekeeping_init by its return value, so if we see a valid
+	 * value returned, update the persistent_clock_exists flag.
+	 */
+	if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
+		persistent_clock_exists = true;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+	timekeeping_forward_now(tk);
+	timekeeping_suspended = 1;
+
+	if (persistent_clock_exists) {
+		/*
+		 * To avoid drift caused by repeated suspend/resumes,
+		 * which each can add ~1 second drift error,
+		 * try to compensate so the difference in system time
+		 * and persistent_clock time stays close to constant.
+		 */
+		delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
+		delta_delta = timespec64_sub(delta, old_delta);
+		if (abs(delta_delta.tv_sec) >= 2) {
+			/*
+			 * if delta_delta is too large, assume time correction
+			 * has occurred and set old_delta to the current delta.
+			 */
+			old_delta = delta;
+		} else {
+			/* Otherwise try to adjust old_system to compensate */
+			timekeeping_suspend_time =
+				timespec64_add(timekeeping_suspend_time, delta_delta);
+		}
+	}
+
+	timekeeping_update(tk, TK_MIRROR);
+	halt_fast_timekeeper(tk);
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	tick_suspend();
+	clocksource_suspend();
+	clockevents_suspend();
+
+	return 0;
+}
+
+/* sysfs resume/suspend bits for timekeeping */
+static struct syscore_ops timekeeping_syscore_ops = {
+	.resume		= timekeeping_resume,
+	.suspend	= timekeeping_suspend,
+};
+
+static int __init timekeeping_init_ops(void)
+{
+	register_syscore_ops(&timekeeping_syscore_ops);
+	return 0;
+}
+device_initcall(timekeeping_init_ops);
+
+/*
+ * Apply a multiplier adjustment to the timekeeper
+ */
+static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
+							 s64 offset,
+							 bool negative,
+							 int adj_scale)
+{
+	s64 interval = tk->cycle_interval;
+	s32 mult_adj = 1;
+
+	if (negative) {
+		mult_adj = -mult_adj;
+		interval = -interval;
+		offset  = -offset;
+	}
+	mult_adj <<= adj_scale;
+	interval <<= adj_scale;
+	offset <<= adj_scale;
+
+	/*
+	 * So the following can be confusing.
+	 *
+	 * To keep things simple, lets assume mult_adj == 1 for now.
+	 *
+	 * When mult_adj != 1, remember that the interval and offset values
+	 * have been appropriately scaled so the math is the same.
+	 *
+	 * The basic idea here is that we're increasing the multiplier
+	 * by one, this causes the xtime_interval to be incremented by
+	 * one cycle_interval. This is because:
+	 *	xtime_interval = cycle_interval * mult
+	 * So if mult is being incremented by one:
+	 *	xtime_interval = cycle_interval * (mult + 1)
+	 * Its the same as:
+	 *	xtime_interval = (cycle_interval * mult) + cycle_interval
+	 * Which can be shortened to:
+	 *	xtime_interval += cycle_interval
+	 *
+	 * So offset stores the non-accumulated cycles. Thus the current
+	 * time (in shifted nanoseconds) is:
+	 *	now = (offset * adj) + xtime_nsec
+	 * Now, even though we're adjusting the clock frequency, we have
+	 * to keep time consistent. In other words, we can't jump back
+	 * in time, and we also want to avoid jumping forward in time.
+	 *
+	 * So given the same offset value, we need the time to be the same
+	 * both before and after the freq adjustment.
+	 *	now = (offset * adj_1) + xtime_nsec_1
+	 *	now = (offset * adj_2) + xtime_nsec_2
+	 * So:
+	 *	(offset * adj_1) + xtime_nsec_1 =
+	 *		(offset * adj_2) + xtime_nsec_2
+	 * And we know:
+	 *	adj_2 = adj_1 + 1
+	 * So:
+	 *	(offset * adj_1) + xtime_nsec_1 =
+	 *		(offset * (adj_1+1)) + xtime_nsec_2
+	 *	(offset * adj_1) + xtime_nsec_1 =
+	 *		(offset * adj_1) + offset + xtime_nsec_2
+	 * Canceling the sides:
+	 *	xtime_nsec_1 = offset + xtime_nsec_2
+	 * Which gives us:
+	 *	xtime_nsec_2 = xtime_nsec_1 - offset
+	 * Which simplfies to:
+	 *	xtime_nsec -= offset
+	 *
+	 * XXX - TODO: Doc ntp_error calculation.
+	 */
+	if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
+		/* NTP adjustment caused clocksource mult overflow */
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	tk->tkr_mono.mult += mult_adj;
+	tk->xtime_interval += interval;
+	tk->tkr_mono.xtime_nsec -= offset;
+	tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
+}
+
+/*
+ * Calculate the multiplier adjustment needed to match the frequency
+ * specified by NTP
+ */
+static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
+							s64 offset)
+{
+	s64 interval = tk->cycle_interval;
+	s64 xinterval = tk->xtime_interval;
+	s64 tick_error;
+	bool negative;
+	u32 adj;
+
+	/* Remove any current error adj from freq calculation */
+	if (tk->ntp_err_mult)
+		xinterval -= tk->cycle_interval;
+
+	tk->ntp_tick = ntp_tick_length();
+
+	/* Calculate current error per tick */
+	tick_error = ntp_tick_length() >> tk->ntp_error_shift;
+	tick_error -= (xinterval + tk->xtime_remainder);
+
+	/* Don't worry about correcting it if its small */
+	if (likely((tick_error >= 0) && (tick_error <= interval)))
+		return;
+
+	/* preserve the direction of correction */
+	negative = (tick_error < 0);
+
+	/* Sort out the magnitude of the correction */
+	tick_error = abs(tick_error);
+	for (adj = 0; tick_error > interval; adj++)
+		tick_error >>= 1;
+
+	/* scale the corrections */
+	timekeeping_apply_adjustment(tk, offset, negative, adj);
+}
+
+/*
+ * Adjust the timekeeper's multiplier to the correct frequency
+ * and also to reduce the accumulated error value.
+ */
+static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
+{
+	/* Correct for the current frequency error */
+	timekeeping_freqadjust(tk, offset);
+
+	/* Next make a small adjustment to fix any cumulative error */
+	if (!tk->ntp_err_mult && (tk->ntp_error > 0)) {
+		tk->ntp_err_mult = 1;
+		timekeeping_apply_adjustment(tk, offset, 0, 0);
+	} else if (tk->ntp_err_mult && (tk->ntp_error <= 0)) {
+		/* Undo any existing error adjustment */
+		timekeeping_apply_adjustment(tk, offset, 1, 0);
+		tk->ntp_err_mult = 0;
+	}
+
+	if (unlikely(tk->tkr_mono.clock->maxadj &&
+		(abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
+			> tk->tkr_mono.clock->maxadj))) {
+		printk_once(KERN_WARNING
+			"Adjusting %s more than 11%% (%ld vs %ld)\n",
+			tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
+			(long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
+	}
+
+	/*
+	 * It may be possible that when we entered this function, xtime_nsec
+	 * was very small.  Further, if we're slightly speeding the clocksource
+	 * in the code above, its possible the required corrective factor to
+	 * xtime_nsec could cause it to underflow.
+	 *
+	 * Now, since we already accumulated the second, cannot simply roll
+	 * the accumulated second back, since the NTP subsystem has been
+	 * notified via second_overflow. So instead we push xtime_nsec forward
+	 * by the amount we underflowed, and add that amount into the error.
+	 *
+	 * We'll correct this error next time through this function, when
+	 * xtime_nsec is not as small.
+	 */
+	if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
+		s64 neg = -(s64)tk->tkr_mono.xtime_nsec;
+		tk->tkr_mono.xtime_nsec = 0;
+		tk->ntp_error += neg << tk->ntp_error_shift;
+	}
+}
+
+/**
+ * accumulate_nsecs_to_secs - Accumulates nsecs into secs
+ *
+ * Helper function that accumulates a the nsecs greater then a second
+ * from the xtime_nsec field to the xtime_secs field.
+ * It also calls into the NTP code to handle leapsecond processing.
+ *
+ */
+static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
+{
+	u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
+	unsigned int clock_set = 0;
+
+	while (tk->tkr_mono.xtime_nsec >= nsecps) {
+		int leap;
+
+		tk->tkr_mono.xtime_nsec -= nsecps;
+		tk->xtime_sec++;
+
+		/* Figure out if its a leap sec and apply if needed */
+		leap = second_overflow(tk->xtime_sec);
+		if (unlikely(leap)) {
+			struct timespec64 ts;
+
+			tk->xtime_sec += leap;
+
+			ts.tv_sec = leap;
+			ts.tv_nsec = 0;
+			tk_set_wall_to_mono(tk,
+				timespec64_sub(tk->wall_to_monotonic, ts));
+
+			__timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
+
+			clock_set = TK_CLOCK_WAS_SET;
+		}
+	}
+	return clock_set;
+}
+
+/**
+ * logarithmic_accumulation - shifted accumulation of cycles
+ *
+ * This functions accumulates a shifted interval of cycles into
+ * into a shifted interval nanoseconds. Allows for O(log) accumulation
+ * loop.
+ *
+ * Returns the unconsumed cycles.
+ */
+static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
+						u32 shift,
+						unsigned int *clock_set)
+{
+	cycle_t interval = tk->cycle_interval << shift;
+	u64 raw_nsecs;
+
+	/* If the offset is smaller then a shifted interval, do nothing */
+	if (offset < interval)
+		return offset;
+
+	/* Accumulate one shifted interval */
+	offset -= interval;
+	tk->tkr_mono.cycle_last += interval;
+	tk->tkr_raw.cycle_last  += interval;
+
+	tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
+	*clock_set |= accumulate_nsecs_to_secs(tk);
+
+	/* Accumulate raw time */
+	raw_nsecs = (u64)tk->raw_interval << shift;
+	raw_nsecs += tk->raw_time.tv_nsec;
+	if (raw_nsecs >= NSEC_PER_SEC) {
+		u64 raw_secs = raw_nsecs;
+		raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
+		tk->raw_time.tv_sec += raw_secs;
+	}
+	tk->raw_time.tv_nsec = raw_nsecs;
+
+	/* Accumulate error between NTP and clock interval */
+	tk->ntp_error += tk->ntp_tick << shift;
+	tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
+						(tk->ntp_error_shift + shift);
+
+	return offset;
+}
+
+/**
+ * update_wall_time - Uses the current clocksource to increment the wall time
+ *
+ */
+void update_wall_time(void)
+{
+	struct timekeeper *real_tk = &tk_core.timekeeper;
+	struct timekeeper *tk = &shadow_timekeeper;
+	cycle_t offset;
+	int shift = 0, maxshift;
+	unsigned int clock_set = 0;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+
+	/* Make sure we're fully resumed: */
+	if (unlikely(timekeeping_suspended))
+		goto out;
+
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
+	offset = real_tk->cycle_interval;
+#else
+	offset = clocksource_delta(tk->tkr_mono.read(tk->tkr_mono.clock),
+				   tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
+#endif
+
+	/* Check if there's really nothing to do */
+	if (offset < real_tk->cycle_interval)
+		goto out;
+
+	/* Do some additional sanity checking */
+	timekeeping_check_update(real_tk, offset);
+
+	/*
+	 * With NO_HZ we may have to accumulate many cycle_intervals
+	 * (think "ticks") worth of time at once. To do this efficiently,
+	 * we calculate the largest doubling multiple of cycle_intervals
+	 * that is smaller than the offset.  We then accumulate that
+	 * chunk in one go, and then try to consume the next smaller
+	 * doubled multiple.
+	 */
+	shift = ilog2(offset) - ilog2(tk->cycle_interval);
+	shift = max(0, shift);
+	/* Bound shift to one less than what overflows tick_length */
+	maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
+	shift = min(shift, maxshift);
+	while (offset >= tk->cycle_interval) {
+		offset = logarithmic_accumulation(tk, offset, shift,
+							&clock_set);
+		if (offset < tk->cycle_interval<<shift)
+			shift--;
+	}
+
+	/* correct the clock when NTP error is too big */
+	timekeeping_adjust(tk, offset);
+
+	/*
+	 * XXX This can be killed once everyone converts
+	 * to the new update_vsyscall.
+	 */
+	old_vsyscall_fixup(tk);
+
+	/*
+	 * Finally, make sure that after the rounding
+	 * xtime_nsec isn't larger than NSEC_PER_SEC
+	 */
+	clock_set |= accumulate_nsecs_to_secs(tk);
+
+	write_seqcount_begin(&tk_core.seq);
+	/*
+	 * Update the real timekeeper.
+	 *
+	 * We could avoid this memcpy by switching pointers, but that
+	 * requires changes to all other timekeeper usage sites as
+	 * well, i.e. move the timekeeper pointer getter into the
+	 * spinlocked/seqcount protected sections. And we trade this
+	 * memcpy under the tk_core.seq against one before we start
+	 * updating.
+	 */
+	memcpy(real_tk, tk, sizeof(*tk));
+	timekeeping_update(real_tk, clock_set);
+	write_seqcount_end(&tk_core.seq);
+out:
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+	if (clock_set)
+		/* Have to call _delayed version, since in irq context*/
+		clock_was_set_delayed();
+}
+
+/**
+ * getboottime64 - Return the real time of system boot.
+ * @ts:		pointer to the timespec64 to be set
+ *
+ * Returns the wall-time of boot in a timespec64.
+ *
+ * This is based on the wall_to_monotonic offset and the total suspend
+ * time. Calls to settimeofday will affect the value returned (which
+ * basically means that however wrong your real time clock is at boot time,
+ * you get the right time here).
+ */
+void getboottime64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
+
+	*ts = ktime_to_timespec64(t);
+}
+EXPORT_SYMBOL_GPL(getboottime64);
+
+unsigned long get_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	return tk->xtime_sec;
+}
+EXPORT_SYMBOL(get_seconds);
+
+struct timespec __current_kernel_time(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	return timespec64_to_timespec(tk_xtime(tk));
+}
+
+struct timespec current_kernel_time(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 now;
+	unsigned long seq;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		now = tk_xtime(tk);
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return timespec64_to_timespec(now);
+}
+EXPORT_SYMBOL(current_kernel_time);
+
+struct timespec64 get_monotonic_coarse64(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 now, mono;
+	unsigned long seq;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		now = tk_xtime(tk);
+		mono = tk->wall_to_monotonic;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	set_normalized_timespec64(&now, now.tv_sec + mono.tv_sec,
+				now.tv_nsec + mono.tv_nsec);
+
+	return now;
+}
+
+/*
+ * Must hold jiffies_lock
+ */
+void do_timer(unsigned long ticks)
+{
+	jiffies_64 += ticks;
+	calc_global_load(ticks);
+}
+
+/**
+ * ktime_get_update_offsets_tick - hrtimer helper
+ * @offs_real:	pointer to storage for monotonic -> realtime offset
+ * @offs_boot:	pointer to storage for monotonic -> boottime offset
+ * @offs_tai:	pointer to storage for monotonic -> clock tai offset
+ *
+ * Returns monotonic time at last tick and various offsets
+ */
+ktime_t ktime_get_update_offsets_tick(ktime_t *offs_real, ktime_t *offs_boot,
+							ktime_t *offs_tai)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	u64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		base = tk->tkr_mono.base;
+		nsecs = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+
+		*offs_real = tk->offs_real;
+		*offs_boot = tk->offs_boot;
+		*offs_tai = tk->offs_tai;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+/**
+ * ktime_get_update_offsets_now - hrtimer helper
+ * @offs_real:	pointer to storage for monotonic -> realtime offset
+ * @offs_boot:	pointer to storage for monotonic -> boottime offset
+ * @offs_tai:	pointer to storage for monotonic -> clock tai offset
+ *
+ * Returns current monotonic time and updates the offsets
+ * Called from hrtimer_interrupt() or retrigger_next_event()
+ */
+ktime_t ktime_get_update_offsets_now(ktime_t *offs_real, ktime_t *offs_boot,
+							ktime_t *offs_tai)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	u64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		base = tk->tkr_mono.base;
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+		*offs_real = tk->offs_real;
+		*offs_boot = tk->offs_boot;
+		*offs_tai = tk->offs_tai;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+#endif
+
+/**
+ * do_adjtimex() - Accessor function to NTP __do_adjtimex function
+ */
+int do_adjtimex(struct timex *txc)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+	struct timespec64 ts;
+	s32 orig_tai, tai;
+	int ret;
+
+	/* Validate the data before disabling interrupts */
+	ret = ntp_validate_timex(txc);
+	if (ret)
+		return ret;
+
+	if (txc->modes & ADJ_SETOFFSET) {
+		struct timespec delta;
+		delta.tv_sec  = txc->time.tv_sec;
+		delta.tv_nsec = txc->time.tv_usec;
+		if (!(txc->modes & ADJ_NANO))
+			delta.tv_nsec *= 1000;
+		ret = timekeeping_inject_offset(&delta);
+		if (ret)
+			return ret;
+	}
+
+	getnstimeofday64(&ts);
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	orig_tai = tai = tk->tai_offset;
+	ret = __do_adjtimex(txc, &ts, &tai);
+
+	if (tai != orig_tai) {
+		__timekeeping_set_tai_offset(tk, tai);
+		timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+	}
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	if (tai != orig_tai)
+		clock_was_set();
+
+	ntp_notify_cmos_timer();
+
+	return ret;
+}
+
+#ifdef CONFIG_NTP_PPS
+/**
+ * hardpps() - Accessor function to NTP __hardpps function
+ */
+void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	__hardpps(phase_ts, raw_ts);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+}
+EXPORT_SYMBOL(hardpps);
+#endif
+
+/**
+ * xtime_update() - advances the timekeeping infrastructure
+ * @ticks:	number of ticks, that have elapsed since the last call.
+ *
+ * Must be called with interrupts disabled.
+ */
+void xtime_update(unsigned long ticks)
+{
+	write_seqlock(&jiffies_lock);
+	do_timer(ticks);
+	write_sequnlock(&jiffies_lock);
+	update_wall_time();
+}