1 files changed, 1423 insertions, 218 deletions

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index a3fa587c350..32d8d6aaedb 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -8,103 +8,469 @@
  *
  */
 
+#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/sysdev.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"
 
-/*
- * This read-write spinlock protects us from races in SMP while
- * playing with xtime and avenrun.
- */
-__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
+#define TK_CLEAR_NTP		(1 << 0)
+#define TK_MIRROR		(1 << 1)
+#define TK_CLOCK_WAS_SET	(1 << 2)
 
+static struct timekeeper timekeeper;
+static DEFINE_RAW_SPINLOCK(timekeeper_lock);
+static seqcount_t timekeeper_seq;
+static struct timekeeper shadow_timekeeper;
 
-/*
- * The current time
- * wall_to_monotonic is what we need to add to xtime (or xtime corrected
- * for sub jiffie times) to get to monotonic time.  Monotonic is pegged
- * at zero at system boot time, so wall_to_monotonic will be negative,
- * however, we will ALWAYS keep the tv_nsec part positive so we can use
- * the usual normalization.
- *
- * wall_to_monotonic is moved after resume from suspend for the monotonic
- * time not to jump. We need to add total_sleep_time to wall_to_monotonic
- * to get the real boot based time offset.
- *
- * - wall_to_monotonic is no longer the boot time, getboottime must be
- * used instead.
- */
-struct timespec xtime __attribute__ ((aligned (16)));
-struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
-static unsigned long total_sleep_time;		/* seconds */
+/* 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 struct timespec xtime_cache __attribute__ ((aligned (16)));
-void update_xtime_cache(u64 nsec)
+static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm)
 {
-	xtime_cache = xtime;
-	timespec_add_ns(&xtime_cache, nsec);
+	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);
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
 }
 
-static struct clocksource *clock; /* pointer to current clocksource */
+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);
+}
 
-#ifdef CONFIG_GENERIC_TIME
 /**
- * __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
+ * tk_setup_internals - Set up internals to use clocksource clock.
+ *
+ * @tk:		The target timekeeper to setup.
+ * @clock:		Pointer to clocksource.
  *
- * private function, must hold xtime_lock lock when being
- * called. Returns the number of nanoseconds since the
- * last call to update_wall_time() (adjusted by NTP scaling)
+ * 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 inline s64 __get_nsec_offset(void)
+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;
+	tk->cycle_last = 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_GETTIMEOFFSET
+u32 (*arch_gettimeoffset)(void);
+
+u32 get_arch_timeoffset(void)
+{
+	if (likely(arch_gettimeoffset))
+		return arch_gettimeoffset();
+	return 0;
+}
+#else
+static 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;
-	s64 ns_offset;
+	struct clocksource *clock;
+	s64 nsec;
 
 	/* read clocksource: */
-	cycle_now = clocksource_read(clock);
+	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 to nanoseconds: */
-	ns_offset = cyc2ns(clock, cycle_delta);
+	/* 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);
 
-	return ns_offset;
+static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
+{
+	raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
 }
 
 /**
- * getnstimeofday - Returns the time of day in a timespec
+ * pvclock_gtod_register_notifier - register a pvclock timedata update listener
+ */
+int pvclock_gtod_register_notifier(struct notifier_block *nb)
+{
+	struct timekeeper *tk = &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);
+
+/* 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();
+	}
+	update_vsyscall(tk);
+	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
+
+	if (action & TK_MIRROR)
+		memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper));
+}
+
+/**
+ * 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;
+	tk->cycle_last = 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
  *
- * Returns the time of day in a timespec.
+ * Updates the time of day in the timespec.
+ * Returns 0 on success, or -ve when suspended (timespec will be undefined).
  */
-void getnstimeofday(struct timespec *ts)
+int __getnstimeofday(struct timespec *ts)
 {
+	struct timekeeper *tk = &timekeeper;
 	unsigned long seq;
-	s64 nsecs;
+	s64 nsecs = 0;
 
 	do {
-		seq = read_seqbegin(&xtime_lock);
+		seq = read_seqcount_begin(&timekeeper_seq);
 
-		*ts = xtime;
-		nsecs = __get_nsec_offset();
+		ts->tv_sec = tk->xtime_sec;
+		nsecs = timekeeping_get_ns(tk);
 
-	} while (read_seqretry(&xtime_lock, seq));
+	} while (read_seqcount_retry(&timekeeper_seq, 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_seqcount_begin(&timekeeper_seq);
+		secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
+		nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec;
+
+	} while (read_seqcount_retry(&timekeeper_seq, 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_seqcount_begin(&timekeeper_seq);
+		ts->tv_sec = tk->xtime_sec;
+		nsec = timekeeping_get_ns(tk);
+		tomono = tk->wall_to_monotonic;
+
+	} while (read_seqcount_retry(&timekeeper_seq, 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);
+
+
+/**
+ * timekeeping_clocktai - Returns the TAI time of day in a timespec
+ * @ts:		pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec.
+ */
+void timekeeping_clocktai(struct timespec *ts)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long seq;
+	u64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+
+		ts->tv_sec = tk->xtime_sec + tk->tai_offset;
+		nsecs = timekeeping_get_ns(tk);
+
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	ts->tv_nsec = 0;
+	timespec_add_ns(ts, nsecs);
+
+}
+EXPORT_SYMBOL(timekeeping_clocktai);
+
+
+/**
+ * ktime_get_clocktai - Returns the TAI time of day in a ktime
+ *
+ * Returns the time of day in a ktime.
+ */
+ktime_t ktime_get_clocktai(void)
+{
+	struct timespec ts;
+
+	timekeeping_clocktai(&ts);
+	return timespec_to_ktime(ts);
+}
+EXPORT_SYMBOL(ktime_get_clocktai);
+
+#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_seqcount_begin(&timekeeper_seq);
+
+		*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_seqcount_retry(&timekeeper_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
@@ -119,120 +485,301 @@ void do_gettimeofday(struct timeval *tv)
 	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(struct timespec *tv)
+int do_settimeofday(const struct timespec *tv)
 {
+	struct timekeeper *tk = &timekeeper;
+	struct timespec ts_delta, xt;
 	unsigned long flags;
-	time_t wtm_sec, sec = tv->tv_sec;
-	long wtm_nsec, nsec = tv->tv_nsec;
 
-	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+	if (!timespec_valid_strict(tv))
 		return -EINVAL;
 
-	write_seqlock_irqsave(&xtime_lock, flags);
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_seq);
 
-	nsec -= __get_nsec_offset();
+	timekeeping_forward_now(tk);
 
-	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
-	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
+	xt = tk_xtime(tk);
+	ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
+	ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
 
-	set_normalized_timespec(&xtime, sec, nsec);
-	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-	update_xtime_cache(0);
+	tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, ts_delta));
 
-	clock->error = 0;
-	ntp_clear();
+	tk_set_xtime(tk, tv);
 
-	update_vsyscall(&xtime, clock);
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
-	write_sequnlock_irqrestore(&xtime_lock, flags);
+	write_seqcount_end(&timekeeper_seq);
+	raw_spin_unlock_irqrestore(&timekeeper_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;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_seq);
+
+	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;
+	}
+
+	tk_xtime_add(tk, ts);
+	tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *ts));
+
+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(&timekeeper_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 = &timekeeper;
+	unsigned int seq;
+	s32 ret;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+		ret = tk->tai_offset;
+	} while (read_seqcount_retry(&timekeeper_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 = &timekeeper;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_seq);
+	__timekeeping_set_tai_offset(tk, tai_offset);
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+	write_seqcount_end(&timekeeper_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 void change_clocksource(void)
+static int change_clocksource(void *data)
 {
-	struct clocksource *new;
-	cycle_t now;
-	u64 nsec;
+	struct timekeeper *tk = &timekeeper;
+	struct clocksource *new, *old;
+	unsigned long flags;
 
-	new = clocksource_get_next();
+	new = (struct clocksource *) data;
 
-	if (clock == new)
-		return;
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_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->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);
 
-	now = clocksource_read(new);
-	nsec =  __get_nsec_offset();
-	timespec_add_ns(&xtime, nsec);
+	write_seqcount_end(&timekeeper_seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
-	clock = new;
-	clock->cycle_last = now;
+	return 0;
+}
 
-	clock->error = 0;
-	clock->xtime_nsec = 0;
-	clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
+/**
+ * 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 = &timekeeper;
 
+	if (tk->clock == clock)
+		return 0;
+	stop_machine(change_clocksource, clock, NULL);
 	tick_clock_notify();
+	return tk->clock == clock ? 0 : -1;
+}
 
-	/*
-	 * We're holding xtime lock and waking up klogd would deadlock
-	 * us on enqueue.  So no printing!
-	printk(KERN_INFO "Time: %s clocksource has been installed.\n",
-	       clock->name);
-	 */
+/**
+ * ktime_get_real - get the real (wall-) time in ktime_t format
+ *
+ * returns the time in ktime_t format
+ */
+ktime_t ktime_get_real(void)
+{
+	struct timespec now;
+
+	getnstimeofday(&now);
+
+	return timespec_to_ktime(now);
 }
-#else
-static inline void change_clocksource(void) { }
-static inline s64 __get_nsec_offset(void) { return 0; }
-#endif
+EXPORT_SYMBOL_GPL(ktime_get_real);
+
+/**
+ * getrawmonotonic - Returns the raw monotonic time in a timespec
+ * @ts:		pointer to the timespec to be set
+ *
+ * Returns the raw monotonic time (completely un-modified by ntp)
+ */
+void getrawmonotonic(struct timespec *ts)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long seq;
+	s64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+		nsecs = timekeeping_get_ns_raw(tk);
+		*ts = tk->raw_time;
+
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	timespec_add_ns(ts, nsecs);
+}
+EXPORT_SYMBOL(getrawmonotonic);
 
 /**
  * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
  */
 int timekeeping_valid_for_hres(void)
 {
+	struct timekeeper *tk = &timekeeper;
 	unsigned long seq;
 	int ret;
 
 	do {
-		seq = read_seqbegin(&xtime_lock);
+		seq = read_seqcount_begin(&timekeeper_seq);
+
+		ret = tk->clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
+
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	return ret;
+}
+
+/**
+ * timekeeping_max_deferment - Returns max time the clocksource can be deferred
+ */
+u64 timekeeping_max_deferment(void)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long seq;
+	u64 ret;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
 
-		ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
+		ret = tk->clock->max_idle_ns;
 
-	} while (read_seqretry(&xtime_lock, seq));
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
 
 	return ret;
 }
 
 /**
- * read_persistent_clock -  Return time in seconds from the persistent clock.
+ * read_persistent_clock -  Return time from the persistent clock.
  *
  * Weak dummy function for arches that do not yet support it.
- * Returns seconds from epoch using the battery backed persistent clock.
- * Returns zero if unsupported.
+ * 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.
  */
-unsigned long __attribute__((weak)) read_persistent_clock(void)
+void __weak read_persistent_clock(struct timespec *ts)
 {
-	return 0;
+	ts->tv_sec = 0;
+	ts->tv_nsec = 0;
+}
+
+/**
+ * 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;
 }
 
 /*
@@ -240,120 +787,278 @@ unsigned long __attribute__((weak)) read_persistent_clock(void)
  */
 void __init timekeeping_init(void)
 {
+	struct timekeeper *tk = &timekeeper;
+	struct clocksource *clock;
 	unsigned long flags;
-	unsigned long sec = read_persistent_clock();
+	struct timespec now, boot, tmp;
+
+	read_persistent_clock(&now);
+
+	if (!timespec_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_exist = true;
+
+	read_boot_clock(&boot);
+	if (!timespec_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;
+	}
 
-	write_seqlock_irqsave(&xtime_lock, flags);
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_seq);
+	ntp_init();
 
-	ntp_clear();
+	clock = clocksource_default_clock();
+	if (clock->enable)
+		clock->enable(clock);
+	tk_setup_internals(tk, clock);
 
-	clock = clocksource_get_next();
-	clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
-	clock->cycle_last = clocksource_read(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);
 
-	xtime.tv_sec = sec;
-	xtime.tv_nsec = 0;
-	set_normalized_timespec(&wall_to_monotonic,
-		-xtime.tv_sec, -xtime.tv_nsec);
-	update_xtime_cache(0);
-	total_sleep_time = 0;
-	write_sequnlock_irqrestore(&xtime_lock, flags);
+	set_normalized_timespec(&tmp, -boot.tv_sec, -boot.tv_nsec);
+	tk_set_wall_to_mono(tk, tmp);
+
+	tmp.tv_sec = 0;
+	tmp.tv_nsec = 0;
+	tk_set_sleep_time(tk, tmp);
+
+	memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper));
+
+	write_seqcount_end(&timekeeper_seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 }
 
-/* flag for if timekeeping is suspended */
-static int timekeeping_suspended;
 /* time in seconds when suspend began */
-static unsigned long timekeeping_suspend_time;
-/* xtime offset when we went into suspend */
-static s64 timekeeping_suspend_nsecs;
+static struct timespec 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 timespec *delta)
+{
+	if (!timespec_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, timespec_sub(tk->wall_to_monotonic, *delta));
+	tk_set_sleep_time(tk, timespec_add(tk->total_sleep_time, *delta));
+	tk_debug_account_sleep_time(delta);
+}
+
+/**
+ * timekeeping_inject_sleeptime - Adds suspend interval to timeekeeping values
+ * @delta: pointer to a timespec delta value
+ *
+ * This hook is for architectures that cannot support read_persistent_clock
+ * because their RTC/persistent clock is only accessible when irqs are enabled.
+ *
+ * This function should only be called by rtc_resume(), and allows
+ * a suspend offset to be injected into the timekeeping values.
+ */
+void timekeeping_inject_sleeptime(struct timespec *delta)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long flags;
+
+	/*
+	 * Make sure we don't set the clock twice, as timekeeping_resume()
+	 * already did it
+	 */
+	if (has_persistent_clock())
+		return;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_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(&timekeeper_seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* signal hrtimers about time change */
+	clock_was_set();
+}
 
 /**
  * timekeeping_resume - Resumes the generic timekeeping subsystem.
- * @dev:	unused
  *
  * This is for the generic clocksource timekeeping.
  * xtime/wall_to_monotonic/jiffies/etc are
  * still managed by arch specific suspend/resume code.
  */
-static int timekeeping_resume(struct sys_device *dev)
+static void timekeeping_resume(void)
 {
+	struct timekeeper *tk = &timekeeper;
+	struct clocksource *clock = tk->clock;
 	unsigned long flags;
-	unsigned long now = read_persistent_clock();
+	struct timespec ts_new, ts_delta;
+	cycle_t cycle_now, cycle_delta;
+	bool suspendtime_found = false;
 
+	read_persistent_clock(&ts_new);
+
+	clockevents_resume();
 	clocksource_resume();
 
-	write_seqlock_irqsave(&xtime_lock, flags);
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_seq);
 
-	if (now && (now > timekeeping_suspend_time)) {
-		unsigned long sleep_length = now - timekeeping_suspend_time;
+	/*
+	 * 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 = clock->read(clock);
+	if ((clock->flags & CLOCK_SOURCE_SUSPEND_NONSTOP) &&
+		cycle_now > clock->cycle_last) {
+		u64 num, max = ULLONG_MAX;
+		u32 mult = clock->mult;
+		u32 shift = clock->shift;
+		s64 nsec = 0;
+
+		cycle_delta = (cycle_now - clock->cycle_last) & clock->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;
 
-		xtime.tv_sec += sleep_length;
-		wall_to_monotonic.tv_sec -= sleep_length;
-		total_sleep_time += sleep_length;
+		ts_delta = ns_to_timespec(nsec);
+		suspendtime_found = true;
+	} else if (timespec_compare(&ts_new, &timekeeping_suspend_time) > 0) {
+		ts_delta = timespec_sub(ts_new, timekeeping_suspend_time);
+		suspendtime_found = true;
 	}
-	/* Make sure that we have the correct xtime reference */
-	timespec_add_ns(&xtime, timekeeping_suspend_nsecs);
-	update_xtime_cache(0);
-	/* re-base the last cycle value */
-	clock->cycle_last = clocksource_read(clock);
-	clock->error = 0;
+
+	if (suspendtime_found)
+		__timekeeping_inject_sleeptime(tk, &ts_delta);
+
+	/* Re-base the last cycle value */
+	tk->cycle_last = clock->cycle_last = cycle_now;
+	tk->ntp_error = 0;
 	timekeeping_suspended = 0;
-	write_sequnlock_irqrestore(&xtime_lock, flags);
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+	write_seqcount_end(&timekeeper_seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
 	touch_softlockup_watchdog();
 
 	clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
 
 	/* Resume hrtimers */
-	hres_timers_resume();
-
-	return 0;
+	hrtimers_resume();
 }
 
-static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
+static int timekeeping_suspend(void)
 {
+	struct timekeeper *tk = &timekeeper;
 	unsigned long flags;
+	struct timespec		delta, delta_delta;
+	static struct timespec	old_delta;
 
-	timekeeping_suspend_time = read_persistent_clock();
+	read_persistent_clock(&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_exist = true;
 
-	write_seqlock_irqsave(&xtime_lock, flags);
-	/* Get the current xtime offset */
-	timekeeping_suspend_nsecs = __get_nsec_offset();
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_seq);
+	timekeeping_forward_now(tk);
 	timekeeping_suspended = 1;
-	write_sequnlock_irqrestore(&xtime_lock, flags);
+
+	/*
+	 * 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 = timespec_sub(tk_xtime(tk), timekeeping_suspend_time);
+	delta_delta = timespec_sub(delta, old_delta);
+	if (abs(delta_delta.tv_sec)  >= 2) {
+		/*
+		 * if delta_delta is too large, assume time correction
+		 * has occured and set old_delta to the current delta.
+		 */
+		old_delta = delta;
+	} else {
+		/* Otherwise try to adjust old_system to compensate */
+		timekeeping_suspend_time =
+			timespec_add(timekeeping_suspend_time, delta_delta);
+	}
+
+	timekeeping_update(tk, TK_MIRROR);
+	write_seqcount_end(&timekeeper_seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
 	clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
+	clocksource_suspend();
+	clockevents_suspend();
 
 	return 0;
 }
 
 /* sysfs resume/suspend bits for timekeeping */
-static struct sysdev_class timekeeping_sysclass = {
-	.name		= "timekeeping",
+static struct syscore_ops timekeeping_syscore_ops = {
 	.resume		= timekeeping_resume,
 	.suspend	= timekeeping_suspend,
 };
 
-static struct sys_device device_timer = {
-	.id		= 0,
-	.cls		= &timekeeping_sysclass,
-};
-
-static int __init timekeeping_init_device(void)
+static int __init timekeeping_init_ops(void)
 {
-	int error = sysdev_class_register(&timekeeping_sysclass);
-	if (!error)
-		error = sysdev_register(&device_timer);
-	return error;
+	register_syscore_ops(&timekeeping_syscore_ops);
+	return 0;
 }
 
-device_initcall(timekeeping_init_device);
+device_initcall(timekeeping_init_ops);
 
 /*
  * If the error is already larger, we look ahead even further
  * to compensate for late or lost adjustments.
  */
-static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
+static __always_inline int timekeeping_bigadjust(struct timekeeper *tk,
+						 s64 error, s64 *interval,
 						 s64 *offset)
 {
 	s64 tick_error, i;
@@ -369,7 +1074,7 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
 	 * here.  This is tuned so that an error of about 1 msec is adjusted
 	 * within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
 	 */
-	error2 = clock->error >> (TICK_LENGTH_SHIFT + 22 - 2 * SHIFT_HZ);
+	error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
 	error2 = abs(error2);
 	for (look_ahead = 0; error2 > 0; look_ahead++)
 		error2 >>= 2;
@@ -378,9 +1083,8 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
 	 * Now calculate the error in (1 << look_ahead) ticks, but first
 	 * remove the single look ahead already included in the error.
 	 */
-	tick_error = current_tick_length() >>
-		(TICK_LENGTH_SHIFT - clock->shift + 1);
-	tick_error -= clock->xtime_interval >> 1;
+	tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1);
+	tick_error -= tk->xtime_interval >> 1;
 	error = ((error - tick_error) >> look_ahead) + tick_error;
 
 	/* Finally calculate the adjustment shift value.  */
@@ -405,95 +1109,343 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
  * this is optimized for the most common adjustments of -1,0,1,
  * for other values we can do a bit more work.
  */
-static void clocksource_adjust(s64 offset)
+static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
 {
-	s64 error, interval = clock->cycle_interval;
+	s64 error, interval = tk->cycle_interval;
 	int adj;
 
-	error = clock->error >> (TICK_LENGTH_SHIFT - clock->shift - 1);
+	/*
+	 * The point of this is to check if the error is greater than half
+	 * an interval.
+	 *
+	 * First we shift it down from NTP_SHIFT to clocksource->shifted nsecs.
+	 *
+	 * Note we subtract one in the shift, so that error is really error*2.
+	 * This "saves" dividing(shifting) interval twice, but keeps the
+	 * (error > interval) comparison as still measuring if error is
+	 * larger than half an interval.
+	 *
+	 * Note: It does not "save" on aggravation when reading the code.
+	 */
+	error = tk->ntp_error >> (tk->ntp_error_shift - 1);
 	if (error > interval) {
+		/*
+		 * We now divide error by 4(via shift), which checks if
+		 * the error is greater than twice the interval.
+		 * If it is greater, we need a bigadjust, if its smaller,
+		 * we can adjust by 1.
+		 */
 		error >>= 2;
 		if (likely(error <= interval))
 			adj = 1;
 		else
-			adj = clocksource_bigadjust(error, &interval, &offset);
-	} else if (error < -interval) {
-		error >>= 2;
-		if (likely(error >= -interval)) {
-			adj = -1;
-			interval = -interval;
-			offset = -offset;
-		} else
-			adj = clocksource_bigadjust(error, &interval, &offset);
-	} else
-		return;
+			adj = timekeeping_bigadjust(tk, error, &interval, &offset);
+	} else {
+		if (error < -interval) {
+			/* See comment above, this is just switched for the negative */
+			error >>= 2;
+			if (likely(error >= -interval)) {
+				adj = -1;
+				interval = -interval;
+				offset = -offset;
+			} else {
+				adj = timekeeping_bigadjust(tk, error, &interval, &offset);
+			}
+		} else {
+			goto out_adjust;
+		}
+	}
+
+	if (unlikely(tk->clock->maxadj &&
+		(tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) {
+		printk_deferred_once(KERN_WARNING
+			"Adjusting %s more than 11%% (%ld vs %ld)\n",
+			tk->clock->name, (long)tk->mult + adj,
+			(long)tk->clock->mult + tk->clock->maxadj);
+	}
+	/*
+	 * So the following can be confusing.
+	 *
+	 * To keep things simple, lets assume adj == 1 for now.
+	 *
+	 * When 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.
+	 */
+	tk->mult += adj;
+	tk->xtime_interval += interval;
+	tk->xtime_nsec -= offset;
+	tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
+
+out_adjust:
+	/*
+	 * 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->xtime_nsec < 0)) {
+		s64 neg = -(s64)tk->xtime_nsec;
+		tk->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->shift;
+	unsigned int clock_set = 0;
+
+	while (tk->xtime_nsec >= nsecps) {
+		int leap;
+
+		tk->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 timespec ts;
+
+			tk->xtime_sec += leap;
+
+			ts.tv_sec = leap;
+			ts.tv_nsec = 0;
+			tk_set_wall_to_mono(tk,
+				timespec_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->cycle_last += interval;
+
+	tk->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 += ntp_tick_length() << shift;
+	tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
+						(tk->ntp_error_shift + shift);
+
+	return offset;
+}
 
-	clock->mult += adj;
-	clock->xtime_interval += interval;
-	clock->xtime_nsec -= offset;
-	clock->error -= (interval - offset) <<
-			(TICK_LENGTH_SHIFT - clock->shift);
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
+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->xtime_nsec & ((1ULL << tk->shift) - 1);
+	tk->xtime_nsec -= remainder;
+	tk->xtime_nsec += 1ULL << tk->shift;
+	tk->ntp_error += remainder << tk->ntp_error_shift;
+	tk->ntp_error -= (1ULL << tk->shift) << tk->ntp_error_shift;
 }
+#else
+#define old_vsyscall_fixup(tk)
+#endif
+
+
 
 /**
  * update_wall_time - Uses the current clocksource to increment the wall time
  *
- * Called from the timer interrupt, must hold a write on xtime_lock.
  */
 void update_wall_time(void)
 {
+	struct clocksource *clock;
+	struct timekeeper *real_tk = &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))
-		return;
+		goto out;
 
-#ifdef CONFIG_GENERIC_TIME
-	offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
+	clock = real_tk->clock;
+
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
+	offset = real_tk->cycle_interval;
 #else
-	offset = clock->cycle_interval;
+	offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
 #endif
-	clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
 
-	/* normally this loop will run just once, however in the
-	 * case of lost or late ticks, it will accumulate correctly.
-	 */
-	while (offset >= clock->cycle_interval) {
-		/* accumulate one interval */
-		clock->xtime_nsec += clock->xtime_interval;
-		clock->cycle_last += clock->cycle_interval;
-		offset -= clock->cycle_interval;
-
-		if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
-			clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
-			xtime.tv_sec++;
-			second_overflow();
-		}
+	/* Check if there's really nothing to do */
+	if (offset < real_tk->cycle_interval)
+		goto out;
 
-		/* accumulate error between NTP and clock interval */
-		clock->error += current_tick_length();
-		clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
+	/*
+	 * 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 */
-	clocksource_adjust(offset);
+	timekeeping_adjust(tk, offset);
 
-	/* store full nanoseconds into xtime */
-	xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
-	clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
+	/*
+	 * XXX This can be killed once everyone converts
+	 * to the new update_vsyscall.
+	 */
+	old_vsyscall_fixup(tk);
 
-	update_xtime_cache(cyc2ns(clock, offset));
+	/*
+	 * Finally, make sure that after the rounding
+	 * xtime_nsec isn't larger than NSEC_PER_SEC
+	 */
+	clock_set |= accumulate_nsecs_to_secs(tk);
 
-	/* check to see if there is a new clocksource to use */
-	change_clocksource();
-	update_vsyscall(&xtime, clock);
+	write_seqcount_begin(&timekeeper_seq);
+	/* Update clock->cycle_last with the new value */
+	clock->cycle_last = tk->cycle_last;
+	/*
+	 * 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 timekeeper_seq against one before we start
+	 * updating.
+	 */
+	memcpy(real_tk, tk, sizeof(*tk));
+	timekeeping_update(real_tk, clock_set);
+	write_seqcount_end(&timekeeper_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();
 }
 
 /**
  * getboottime - Return the real time of system boot.
  * @ts:		pointer to the timespec to be set
  *
- * Returns the time of day in a timespec.
+ * Returns the wall-time of boot in a timespec.
  *
  * This is based on the wall_to_monotonic offset and the total suspend
  * time. Calls to settimeofday will affect the value returned (which
@@ -502,10 +1454,67 @@ void update_wall_time(void)
  */
 void getboottime(struct timespec *ts)
 {
-	set_normalized_timespec(ts,
-		- (wall_to_monotonic.tv_sec + total_sleep_time),
-		- wall_to_monotonic.tv_nsec);
+	struct timekeeper *tk = &timekeeper;
+	struct timespec boottime = {
+		.tv_sec = tk->wall_to_monotonic.tv_sec +
+				tk->total_sleep_time.tv_sec,
+		.tv_nsec = tk->wall_to_monotonic.tv_nsec +
+				tk->total_sleep_time.tv_nsec
+	};
+
+	set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
 }
+EXPORT_SYMBOL_GPL(getboottime);
+
+/**
+ * get_monotonic_boottime - Returns monotonic time since boot
+ * @ts:		pointer to the timespec to be set
+ *
+ * Returns the monotonic time since boot in a timespec.
+ *
+ * This is similar to CLOCK_MONTONIC/ktime_get_ts, but also
+ * includes the time spent in suspend.
+ */
+void get_monotonic_boottime(struct timespec *ts)
+{
+	struct timekeeper *tk = &timekeeper;
+	struct timespec tomono, sleep;
+	s64 nsec;
+	unsigned int seq;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+		ts->tv_sec = tk->xtime_sec;
+		nsec = timekeeping_get_ns(tk);
+		tomono = tk->wall_to_monotonic;
+		sleep = tk->total_sleep_time;
+
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	ts->tv_sec += tomono.tv_sec + sleep.tv_sec;
+	ts->tv_nsec = 0;
+	timespec_add_ns(ts, nsec + tomono.tv_nsec + sleep.tv_nsec);
+}
+EXPORT_SYMBOL_GPL(get_monotonic_boottime);
+
+/**
+ * ktime_get_boottime - Returns monotonic time since boot in a ktime
+ *
+ * Returns the monotonic time since boot in a ktime
+ *
+ * This is similar to CLOCK_MONTONIC/ktime_get, but also
+ * includes the time spent in suspend.
+ */
+ktime_t ktime_get_boottime(void)
+{
+	struct timespec ts;
+
+	get_monotonic_boottime(&ts);
+	return timespec_to_ktime(ts);
+}
+EXPORT_SYMBOL_GPL(ktime_get_boottime);
 
 /**
  * monotonic_to_bootbased - Convert the monotonic time to boot based.
@@ -513,27 +1522,223 @@ void getboottime(struct timespec *ts)
  */
 void monotonic_to_bootbased(struct timespec *ts)
 {
-	ts->tv_sec += total_sleep_time;
+	struct timekeeper *tk = &timekeeper;
+
+	*ts = timespec_add(*ts, tk->total_sleep_time);
 }
+EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
 
 unsigned long get_seconds(void)
 {
-	return xtime_cache.tv_sec;
+	struct timekeeper *tk = &timekeeper;
+
+	return tk->xtime_sec;
 }
 EXPORT_SYMBOL(get_seconds);
 
+struct timespec __current_kernel_time(void)
+{
+	struct timekeeper *tk = &timekeeper;
+
+	return tk_xtime(tk);
+}
 
 struct timespec current_kernel_time(void)
 {
+	struct timekeeper *tk = &timekeeper;
 	struct timespec now;
 	unsigned long seq;
 
 	do {
-		seq = read_seqbegin(&xtime_lock);
+		seq = read_seqcount_begin(&timekeeper_seq);
 
-		now = xtime_cache;
-	} while (read_seqretry(&xtime_lock, seq));
+		now = tk_xtime(tk);
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
 
 	return now;
 }
 EXPORT_SYMBOL(current_kernel_time);
+
+struct timespec get_monotonic_coarse(void)
+{
+	struct timekeeper *tk = &timekeeper;
+	struct timespec now, mono;
+	unsigned long seq;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+
+		now = tk_xtime(tk);
+		mono = tk->wall_to_monotonic;
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	set_normalized_timespec(&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);
+}
+
+/**
+ * get_xtime_and_monotonic_and_sleep_offset() - get xtime, wall_to_monotonic,
+ *    and sleep offsets.
+ * @xtim:	pointer to timespec to be set with xtime
+ * @wtom:	pointer to timespec to be set with wall_to_monotonic
+ * @sleep:	pointer to timespec to be set with time in suspend
+ */
+void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim,
+				struct timespec *wtom, struct timespec *sleep)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long seq;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+		*xtim = tk_xtime(tk);
+		*wtom = tk->wall_to_monotonic;
+		*sleep = tk->total_sleep_time;
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+/**
+ * ktime_get_update_offsets - 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(ktime_t *offs_real, ktime_t *offs_boot,
+							ktime_t *offs_tai)
+{
+	struct timekeeper *tk = &timekeeper;
+	ktime_t now;
+	unsigned int seq;
+	u64 secs, nsecs;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+
+		secs = tk->xtime_sec;
+		nsecs = timekeeping_get_ns(tk);
+
+		*offs_real = tk->offs_real;
+		*offs_boot = tk->offs_boot;
+		*offs_tai = tk->offs_tai;
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	now = ktime_add_ns(ktime_set(secs, 0), nsecs);
+	now = ktime_sub(now, *offs_real);
+	return now;
+}
+#endif
+
+/**
+ * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format
+ */
+ktime_t ktime_get_monotonic_offset(void)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long seq;
+	struct timespec wtom;
+
+	do {
+		seq = read_seqcount_begin(&timekeeper_seq);
+		wtom = tk->wall_to_monotonic;
+	} while (read_seqcount_retry(&timekeeper_seq, seq));
+
+	return timespec_to_ktime(wtom);
+}
+EXPORT_SYMBOL_GPL(ktime_get_monotonic_offset);
+
+/**
+ * do_adjtimex() - Accessor function to NTP __do_adjtimex function
+ */
+int do_adjtimex(struct timex *txc)
+{
+	struct timekeeper *tk = &timekeeper;
+	unsigned long flags;
+	struct timespec 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;
+	}
+
+	getnstimeofday(&ts);
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&timekeeper_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(&timekeeper_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(&timekeeper_seq);
+
+	__hardpps(phase_ts, raw_ts);
+
+	write_seqcount_end(&timekeeper_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();
+}