Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull time(r) updates from Thomas Gleixner:
 "A small set of updates for timers and timekeeping:

   - The most interesting change is the consolidation of clock MONOTONIC
     and clock BOOTTIME.

     Clock MONOTONIC behaves now exactly like clock BOOTTIME and does
     not longer ignore the time spent in suspend. A new clock
     MONOTONIC_ACTIVE is provived which behaves like clock MONOTONIC in
     kernels before this change. This allows applications to
     programmatically check for the clock MONOTONIC behaviour.

     As discussed in the review thread, this has the potential of
     breaking user space and we might have to revert this. Knock on wood
     that we can avoid that exercise.

   - Updates to the NTP mechanism to improve accuracy

   - A new kernel internal data structure to aid the ongoing Y2038 work.

   - Cleanups and simplifications of the clocksource code.

   - Make the alarmtimer code play nicely with debugobjects"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  alarmtimer: Init nanosleep alarm timer on stack
  y2038: Introduce struct __kernel_old_timeval
  tracing: Unify the "boot" and "mono" tracing clocks
  hrtimer: Unify MONOTONIC and BOOTTIME clock behavior
  posix-timers: Unify MONOTONIC and BOOTTIME clock behavior
  timekeeping: Remove boot time specific code
  Input: Evdev - unify MONOTONIC and BOOTTIME clock behavior
  timekeeping: Make the MONOTONIC clock behave like the BOOTTIME clock
  timekeeping: Add the new CLOCK_MONOTONIC_ACTIVE clock
  timekeeping/ntp: Determine the multiplier directly from NTP tick length
  timekeeping/ntp: Don't align NTP frequency adjustments to ticks
  clocksource: Use ATTRIBUTE_GROUPS
  clocksource: Use DEVICE_ATTR_RW/RO/WO to define device attributes
  clocksource: Don't walk the clocksource list for empty override

11 files changed, 199 insertions, 207 deletions

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index ec09ce9a6012..639321bf2e39 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -326,6 +326,17 @@ static int alarmtimer_resume(struct device *dev)
 }
 #endif
 
+static void
+__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
+	     enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
+{
+	timerqueue_init(&alarm->node);
+	alarm->timer.function = alarmtimer_fired;
+	alarm->function = function;
+	alarm->type = type;
+	alarm->state = ALARMTIMER_STATE_INACTIVE;
+}
+
 /**
  * alarm_init - Initialize an alarm structure
  * @alarm: ptr to alarm to be initialized
@@ -335,13 +346,9 @@ static int alarmtimer_resume(struct device *dev)
 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 		enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 {
-	timerqueue_init(&alarm->node);
 	hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
-			HRTIMER_MODE_ABS);
-	alarm->timer.function = alarmtimer_fired;
-	alarm->function = function;
-	alarm->type = type;
-	alarm->state = ALARMTIMER_STATE_INACTIVE;
+		     HRTIMER_MODE_ABS);
+	__alarm_init(alarm, type, function);
 }
 EXPORT_SYMBOL_GPL(alarm_init);
 
@@ -719,6 +726,8 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
 
 	__set_current_state(TASK_RUNNING);
 
+	destroy_hrtimer_on_stack(&alarm->timer);
+
 	if (!alarm->data)
 		return 0;
 
@@ -740,6 +749,15 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
 	return -ERESTART_RESTARTBLOCK;
 }
 
+static void
+alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
+		    enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
+{
+	hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
+			      HRTIMER_MODE_ABS);
+	__alarm_init(alarm, type, function);
+}
+
 /**
  * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
  * @restart: ptr to restart block
@@ -752,7 +770,7 @@ static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
 	ktime_t exp = restart->nanosleep.expires;
 	struct alarm alarm;
 
-	alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
+	alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
 
 	return alarmtimer_do_nsleep(&alarm, exp, type);
 }
@@ -784,7 +802,7 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 	if (!capable(CAP_WAKE_ALARM))
 		return -EPERM;
 
-	alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
+	alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
 
 	exp = timespec64_to_ktime(*tsreq);
 	/* Convert (if necessary) to absolute time */
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 65f9e3f24dde..0e974cface0b 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -594,6 +594,9 @@ static void __clocksource_select(bool skipcur)
 	if (!best)
 		return;
 
+	if (!strlen(override_name))
+		goto found;
+
 	/* Check for the override clocksource. */
 	list_for_each_entry(cs, &clocksource_list, list) {
 		if (skipcur && cs == curr_clocksource)
@@ -625,6 +628,7 @@ static void __clocksource_select(bool skipcur)
 		break;
 	}
 
+found:
 	if (curr_clocksource != best && !timekeeping_notify(best)) {
 		pr_info("Switched to clocksource %s\n", best->name);
 		curr_clocksource = best;
@@ -853,16 +857,16 @@ EXPORT_SYMBOL(clocksource_unregister);
 
 #ifdef CONFIG_SYSFS
 /**
- * sysfs_show_current_clocksources - sysfs interface for current clocksource
+ * current_clocksource_show - sysfs interface for current clocksource
  * @dev:	unused
  * @attr:	unused
  * @buf:	char buffer to be filled with clocksource list
  *
  * Provides sysfs interface for listing current clocksource.
  */
-static ssize_t
-sysfs_show_current_clocksources(struct device *dev,
-				struct device_attribute *attr, char *buf)
+static ssize_t current_clocksource_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
 {
 	ssize_t count = 0;
 
@@ -891,7 +895,7 @@ ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt)
 }
 
 /**
- * sysfs_override_clocksource - interface for manually overriding clocksource
+ * current_clocksource_store - interface for manually overriding clocksource
  * @dev:	unused
  * @attr:	unused
  * @buf:	name of override clocksource
@@ -900,9 +904,9 @@ ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt)
  * Takes input from sysfs interface for manually overriding the default
  * clocksource selection.
  */
-static ssize_t sysfs_override_clocksource(struct device *dev,
-					  struct device_attribute *attr,
-					  const char *buf, size_t count)
+static ssize_t current_clocksource_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
 {
 	ssize_t ret;
 
@@ -916,9 +920,10 @@ static ssize_t sysfs_override_clocksource(struct device *dev,
 
 	return ret;
 }
+static DEVICE_ATTR_RW(current_clocksource);
 
 /**
- * sysfs_unbind_current_clocksource - interface for manually unbinding clocksource
+ * unbind_clocksource_store - interface for manually unbinding clocksource
  * @dev:	unused
  * @attr:	unused
  * @buf:	unused
@@ -926,7 +931,7 @@ static ssize_t sysfs_override_clocksource(struct device *dev,
  *
  * Takes input from sysfs interface for manually unbinding a clocksource.
  */
-static ssize_t sysfs_unbind_clocksource(struct device *dev,
+static ssize_t unbind_clocksource_store(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t count)
 {
@@ -950,19 +955,19 @@ static ssize_t sysfs_unbind_clocksource(struct device *dev,
 
 	return ret ? ret : count;
 }
+static DEVICE_ATTR_WO(unbind_clocksource);
 
 /**
- * sysfs_show_available_clocksources - sysfs interface for listing clocksource
+ * available_clocksource_show - sysfs interface for listing clocksource
  * @dev:	unused
  * @attr:	unused
  * @buf:	char buffer to be filled with clocksource list
  *
  * Provides sysfs interface for listing registered clocksources
  */
-static ssize_t
-sysfs_show_available_clocksources(struct device *dev,
-				  struct device_attribute *attr,
-				  char *buf)
+static ssize_t available_clocksource_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
 {
 	struct clocksource *src;
 	ssize_t count = 0;
@@ -986,17 +991,15 @@ sysfs_show_available_clocksources(struct device *dev,
 
 	return count;
 }
+static DEVICE_ATTR_RO(available_clocksource);
 
-/*
- * Sysfs setup bits:
- */
-static DEVICE_ATTR(current_clocksource, 0644, sysfs_show_current_clocksources,
-		   sysfs_override_clocksource);
-
-static DEVICE_ATTR(unbind_clocksource, 0200, NULL, sysfs_unbind_clocksource);
-
-static DEVICE_ATTR(available_clocksource, 0444,
-		   sysfs_show_available_clocksources, NULL);
+static struct attribute *clocksource_attrs[] = {
+	&dev_attr_current_clocksource.attr,
+	&dev_attr_unbind_clocksource.attr,
+	&dev_attr_available_clocksource.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(clocksource);
 
 static struct bus_type clocksource_subsys = {
 	.name = "clocksource",
@@ -1006,6 +1009,7 @@ static struct bus_type clocksource_subsys = {
 static struct device device_clocksource = {
 	.id	= 0,
 	.bus	= &clocksource_subsys,
+	.groups	= clocksource_groups,
 };
 
 static int __init init_clocksource_sysfs(void)
@@ -1014,17 +1018,7 @@ static int __init init_clocksource_sysfs(void)
 
 	if (!error)
 		error = device_register(&device_clocksource);
-	if (!error)
-		error = device_create_file(
-				&device_clocksource,
-				&dev_attr_current_clocksource);
-	if (!error)
-		error = device_create_file(&device_clocksource,
-					   &dev_attr_unbind_clocksource);
-	if (!error)
-		error = device_create_file(
-				&device_clocksource,
-				&dev_attr_available_clocksource);
+
 	return error;
 }
 
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 23788100e214..9b082ce86325 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -91,11 +91,6 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
 			.get_time = &ktime_get_real,
 		},
 		{
-			.index = HRTIMER_BASE_BOOTTIME,
-			.clockid = CLOCK_BOOTTIME,
-			.get_time = &ktime_get_boottime,
-		},
-		{
 			.index = HRTIMER_BASE_TAI,
 			.clockid = CLOCK_TAI,
 			.get_time = &ktime_get_clocktai,
@@ -111,11 +106,6 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
 			.get_time = &ktime_get_real,
 		},
 		{
-			.index = HRTIMER_BASE_BOOTTIME_SOFT,
-			.clockid = CLOCK_BOOTTIME,
-			.get_time = &ktime_get_boottime,
-		},
-		{
 			.index = HRTIMER_BASE_TAI_SOFT,
 			.clockid = CLOCK_TAI,
 			.get_time = &ktime_get_clocktai,
@@ -129,7 +119,7 @@ static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
 
 	[CLOCK_REALTIME]	= HRTIMER_BASE_REALTIME,
 	[CLOCK_MONOTONIC]	= HRTIMER_BASE_MONOTONIC,
-	[CLOCK_BOOTTIME]	= HRTIMER_BASE_BOOTTIME,
+	[CLOCK_BOOTTIME]	= HRTIMER_BASE_MONOTONIC,
 	[CLOCK_TAI]		= HRTIMER_BASE_TAI,
 };
 
@@ -565,14 +555,12 @@ __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base, unsigned int active_
 static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
 {
 	ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
-	ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
 	ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
 
 	ktime_t now = ktime_get_update_offsets_now(&base->clock_was_set_seq,
-					    offs_real, offs_boot, offs_tai);
+						   offs_real, offs_tai);
 
 	base->clock_base[HRTIMER_BASE_REALTIME_SOFT].offset = *offs_real;
-	base->clock_base[HRTIMER_BASE_BOOTTIME_SOFT].offset = *offs_boot;
 	base->clock_base[HRTIMER_BASE_TAI_SOFT].offset = *offs_tai;
 
 	return now;
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index b258bee13b02..6259dbc0191a 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -73,6 +73,8 @@ int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
 	case CLOCK_BOOTTIME:
 		get_monotonic_boottime64(tp);
 		break;
+	case CLOCK_MONOTONIC_ACTIVE:
+		ktime_get_active_ts64(tp);
 	default:
 		return -EINVAL;
 	}
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 10b7186d0638..b6899b5060bd 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -252,15 +252,16 @@ static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *
 	return 0;
 }
 
-static int posix_get_boottime(const clockid_t which_clock, struct timespec64 *tp)
+static int posix_get_tai(clockid_t which_clock, struct timespec64 *tp)
 {
-	get_monotonic_boottime64(tp);
+	timekeeping_clocktai64(tp);
 	return 0;
 }
 
-static int posix_get_tai(clockid_t which_clock, struct timespec64 *tp)
+static int posix_get_monotonic_active(clockid_t which_clock,
+				      struct timespec64 *tp)
 {
-	timekeeping_clocktai64(tp);
+	ktime_get_active_ts64(tp);
 	return 0;
 }
 
@@ -1316,19 +1317,9 @@ static const struct k_clock clock_tai = {
 	.timer_arm		= common_hrtimer_arm,
 };
 
-static const struct k_clock clock_boottime = {
+static const struct k_clock clock_monotonic_active = {
 	.clock_getres		= posix_get_hrtimer_res,
-	.clock_get		= posix_get_boottime,
-	.nsleep			= common_nsleep,
-	.timer_create		= common_timer_create,
-	.timer_set		= common_timer_set,
-	.timer_get		= common_timer_get,
-	.timer_del		= common_timer_del,
-	.timer_rearm		= common_hrtimer_rearm,
-	.timer_forward		= common_hrtimer_forward,
-	.timer_remaining	= common_hrtimer_remaining,
-	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
-	.timer_arm		= common_hrtimer_arm,
+	.clock_get		= posix_get_monotonic_active,
 };
 
 static const struct k_clock * const posix_clocks[] = {
@@ -1339,10 +1330,11 @@ static const struct k_clock * const posix_clocks[] = {
 	[CLOCK_MONOTONIC_RAW]		= &clock_monotonic_raw,
 	[CLOCK_REALTIME_COARSE]		= &clock_realtime_coarse,
 	[CLOCK_MONOTONIC_COARSE]	= &clock_monotonic_coarse,
-	[CLOCK_BOOTTIME]		= &clock_boottime,
+	[CLOCK_BOOTTIME]		= &clock_monotonic,
 	[CLOCK_REALTIME_ALARM]		= &alarm_clock,
 	[CLOCK_BOOTTIME_ALARM]		= &alarm_clock,
 	[CLOCK_TAI]			= &clock_tai,
+	[CLOCK_MONOTONIC_ACTIVE]	= &clock_monotonic_active,
 };
 
 static const struct k_clock *clockid_to_kclock(const clockid_t id)
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 49edc1c4f3e6..099572ca4a8f 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -419,6 +419,19 @@ void tick_suspend_local(void)
 	clockevents_shutdown(td->evtdev);
 }
 
+static void tick_forward_next_period(void)
+{
+	ktime_t delta, now = ktime_get();
+	u64 n;
+
+	delta = ktime_sub(now, tick_next_period);
+	n = ktime_divns(delta, tick_period);
+	tick_next_period += n * tick_period;
+	if (tick_next_period < now)
+		tick_next_period += tick_period;
+	tick_sched_forward_next_period();
+}
+
 /**
  * tick_resume_local - Resume the local tick device
  *
@@ -431,6 +444,8 @@ void tick_resume_local(void)
 	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
 	bool broadcast = tick_resume_check_broadcast();
 
+	tick_forward_next_period();
+
 	clockevents_tick_resume(td->evtdev);
 	if (!broadcast) {
 		if (td->mode == TICKDEV_MODE_PERIODIC)
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index e277284c2831..21efab7485ca 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -141,6 +141,12 @@ static inline void tick_check_oneshot_broadcast_this_cpu(void) { }
 static inline bool tick_broadcast_oneshot_available(void) { return tick_oneshot_possible(); }
 #endif /* !(BROADCAST && ONESHOT) */
 
+#if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
+extern void tick_sched_forward_next_period(void);
+#else
+static inline void tick_sched_forward_next_period(void) { }
+#endif
+
 /* NO_HZ_FULL internal */
 #ifdef CONFIG_NO_HZ_FULL
 extern void tick_nohz_init(void);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 5d4a0342f934..f3ab08caa2c3 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -52,6 +52,15 @@ struct tick_sched *tick_get_tick_sched(int cpu)
 static ktime_t last_jiffies_update;
 
 /*
+ * Called after resume. Make sure that jiffies are not fast forwarded due to
+ * clock monotonic being forwarded by the suspended time.
+ */
+void tick_sched_forward_next_period(void)
+{
+	last_jiffies_update = tick_next_period;
+}
+
+/*
  * Must be called with interrupts disabled !
  */
 static void tick_do_update_jiffies64(ktime_t now)
diff --git a/kernel/time/time.c b/kernel/time/time.c
index bd4e6c7dd689..3044d48ebe56 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -488,6 +488,18 @@ struct timeval ns_to_timeval(const s64 nsec)
 }
 EXPORT_SYMBOL(ns_to_timeval);
 
+struct __kernel_old_timeval ns_to_kernel_old_timeval(const s64 nsec)
+{
+	struct timespec64 ts = ns_to_timespec64(nsec);
+	struct __kernel_old_timeval tv;
+
+	tv.tv_sec = ts.tv_sec;
+	tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
+
+	return tv;
+}
+EXPORT_SYMBOL(ns_to_kernel_old_timeval);
+
 /**
  * set_normalized_timespec - set timespec sec and nsec parts and normalize
  *
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index cd03317e7b57..ca90219a1e73 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -138,7 +138,12 @@ static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
 
 static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
 {
-	tk->offs_boot = ktime_add(tk->offs_boot, delta);
+	/* Update both bases so mono and raw stay coupled. */
+	tk->tkr_mono.base += delta;
+	tk->tkr_raw.base += delta;
+
+	/* Accumulate time spent in suspend */
+	tk->time_suspended += delta;
 }
 
 /*
@@ -332,6 +337,7 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
 	tk->tkr_mono.mult = clock->mult;
 	tk->tkr_raw.mult = clock->mult;
 	tk->ntp_err_mult = 0;
+	tk->skip_second_overflow = 0;
 }
 
 /* Timekeeper helper functions. */
@@ -467,36 +473,6 @@ u64 ktime_get_raw_fast_ns(void)
 }
 EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
 
-/**
- * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
- *
- * To keep it NMI safe since we're accessing from tracing, we're not using a
- * separate timekeeper with updates to monotonic clock and boot offset
- * protected with seqlocks. This has the following minor side effects:
- *
- * (1) Its possible that a timestamp be taken after the boot offset is updated
- * but before the timekeeper is updated. If this happens, the new boot offset
- * is added to the old timekeeping making the clock appear to update slightly
- * earlier:
- *    CPU 0                                        CPU 1
- *    timekeeping_inject_sleeptime64()
- *    __timekeeping_inject_sleeptime(tk, delta);
- *                                                 timestamp();
- *    timekeeping_update(tk, TK_CLEAR_NTP...);
- *
- * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
- * partially updated.  Since the tk->offs_boot update is a rare event, this
- * should be a rare occurrence which postprocessing should be able to handle.
- */
-u64 notrace ktime_get_boot_fast_ns(void)
-{
-	struct timekeeper *tk = &tk_core.timekeeper;
-
-	return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
-}
-EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
-
-
 /*
  * See comment for __ktime_get_fast_ns() vs. timestamp ordering
  */
@@ -788,7 +764,6 @@ EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
 
 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,
 };
 
@@ -886,6 +861,39 @@ void ktime_get_ts64(struct timespec64 *ts)
 EXPORT_SYMBOL_GPL(ktime_get_ts64);
 
 /**
+ * ktime_get_active_ts64 - Get the active non-suspended monotonic clock
+ * @ts:		pointer to timespec variable
+ *
+ * The function calculates the monotonic clock from the realtime clock and
+ * the wall_to_monotonic offset, subtracts the accumulated suspend time and
+ * stores the result in normalized timespec64 format in the variable
+ * pointed to by @ts.
+ */
+void ktime_get_active_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 tomono, tsusp;
+	u64 nsec, nssusp;
+	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;
+		nssusp = tk->time_suspended;
+	} 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);
+	tsusp = ns_to_timespec64(nssusp);
+	*ts = timespec64_sub(*ts, tsusp);
+}
+
+/**
  * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
  *
  * Returns the seconds portion of CLOCK_MONOTONIC with a single non
@@ -1585,7 +1593,6 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
 		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);
 }
@@ -1799,20 +1806,19 @@ device_initcall(timekeeping_init_ops);
  */
 static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
 							 s64 offset,
-							 bool negative,
-							 int adj_scale)
+							 s32 mult_adj)
 {
 	s64 interval = tk->cycle_interval;
-	s32 mult_adj = 1;
 
-	if (negative) {
-		mult_adj = -mult_adj;
+	if (mult_adj == 0) {
+		return;
+	} else if (mult_adj == -1) {
 		interval = -interval;
-		offset  = -offset;
+		offset = -offset;
+	} else if (mult_adj != 1) {
+		interval *= mult_adj;
+		offset *= mult_adj;
 	}
-	mult_adj <<= adj_scale;
-	interval <<= adj_scale;
-	offset <<= adj_scale;
 
 	/*
 	 * So the following can be confusing.
@@ -1860,8 +1866,6 @@ static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
 	 *	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 */
@@ -1872,89 +1876,38 @@ static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
 	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
+ * Adjust the timekeeper's multiplier to the correct frequency
+ * and also to reduce the accumulated error value.
  */
-static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
-							s64 offset)
+static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
 {
-	s64 interval = tk->cycle_interval;
-	s64 xinterval = tk->xtime_interval;
-	u32 base = tk->tkr_mono.clock->mult;
-	u32 max = tk->tkr_mono.clock->maxadj;
-	u32 cur_adj = tk->tkr_mono.mult;
-	s64 tick_error;
-	bool negative;
-	u32 adj_scale;
-
-	/* 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);
+	u32 mult;
 
-	/* If any adjustment would pass the max, just return */
-	if (negative && (cur_adj - 1) <= (base - max))
-		return;
-	if (!negative && (cur_adj + 1) >= (base + max))
-		return;
 	/*
-	 * Sort out the magnitude of the correction, but
-	 * avoid making so large a correction that we go
-	 * over the max adjustment.
+	 * Determine the multiplier from the current NTP tick length.
+	 * Avoid expensive division when the tick length doesn't change.
 	 */
-	adj_scale = 0;
-	tick_error = abs(tick_error);
-	while (tick_error > interval) {
-		u32 adj = 1 << (adj_scale + 1);
-
-		/* Check if adjustment gets us within 1 unit from the max */
-		if (negative && (cur_adj - adj) <= (base - max))
-			break;
-		if (!negative && (cur_adj + adj) >= (base + max))
-			break;
-
-		adj_scale++;
-		tick_error >>= 1;
+	if (likely(tk->ntp_tick == ntp_tick_length())) {
+		mult = tk->tkr_mono.mult - tk->ntp_err_mult;
+	} else {
+		tk->ntp_tick = ntp_tick_length();
+		mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
+				 tk->xtime_remainder, tk->cycle_interval);
 	}
 
-	/* scale the corrections */
-	timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
-}
+	/*
+	 * If the clock is behind the NTP time, increase the multiplier by 1
+	 * to catch up with it. If it's ahead and there was a remainder in the
+	 * tick division, the clock will slow down. Otherwise it will stay
+	 * ahead until the tick length changes to a non-divisible value.
+	 */
+	tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
+	mult += tk->ntp_err_mult;
 
-/*
- * 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;
-	}
+	timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
 
 	if (unlikely(tk->tkr_mono.clock->maxadj &&
 		(abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
@@ -1971,18 +1924,15 @@ static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
 	 * 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.
+	 * Now, since we have already accumulated the second and the NTP
+	 * subsystem has been notified via second_overflow(), we need to skip
+	 * the next update.
 	 */
 	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;
+		tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
+							tk->tkr_mono.shift;
+		tk->xtime_sec--;
+		tk->skip_second_overflow = 1;
 	}
 }
 
@@ -2005,6 +1955,15 @@ static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
 		tk->tkr_mono.xtime_nsec -= nsecps;
 		tk->xtime_sec++;
 
+		/*
+		 * Skip NTP update if this second was accumulated before,
+		 * i.e. xtime_nsec underflowed in timekeeping_adjust()
+		 */
+		if (unlikely(tk->skip_second_overflow)) {
+			tk->skip_second_overflow = 0;
+			continue;
+		}
+
 		/* Figure out if its a leap sec and apply if needed */
 		leap = second_overflow(tk->xtime_sec);
 		if (unlikely(leap)) {
@@ -2121,7 +2080,7 @@ void update_wall_time(void)
 			shift--;
 	}
 
-	/* correct the clock when NTP error is too big */
+	/* Adjust the multiplier to correct NTP error */
 	timekeeping_adjust(tk, offset);
 
 	/*
@@ -2166,7 +2125,7 @@ out:
 void getboottime64(struct timespec64 *ts)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
-	ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
+	ktime_t t = ktime_sub(tk->offs_real, tk->time_suspended);
 
 	*ts = ktime_to_timespec64(t);
 }
@@ -2236,7 +2195,6 @@ void do_timer(unsigned long ticks)
  * ktime_get_update_offsets_now - hrtimer helper
  * @cwsseq:	pointer to check and store the clock was set sequence number
  * @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 if the
@@ -2246,7 +2204,7 @@ void do_timer(unsigned long ticks)
  * Called from hrtimer_interrupt() or retrigger_next_event()
  */
 ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
-				     ktime_t *offs_boot, ktime_t *offs_tai)
+				     ktime_t *offs_tai)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned int seq;
@@ -2263,7 +2221,6 @@ ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
 		if (*cwsseq != tk->clock_was_set_seq) {
 			*cwsseq = tk->clock_was_set_seq;
 			*offs_real = tk->offs_real;
-			*offs_boot = tk->offs_boot;
 			*offs_tai = tk->offs_tai;
 		}
 
diff --git a/kernel/time/timekeeping.h b/kernel/time/timekeeping.h
index 7a9b4eb7a1d5..79b67f5e0343 100644
--- a/kernel/time/timekeeping.h
+++ b/kernel/time/timekeeping.h
@@ -6,7 +6,6 @@
  */
 extern ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq,
 					    ktime_t *offs_real,
-					    ktime_t *offs_boot,
 					    ktime_t *offs_tai);
 
 extern int timekeeping_valid_for_hres(void);