Merge branch 'fortglx/4.15/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

Pull timekeeping updates from John Stultz:

 - More y2038 work from Arnd Bergmann

 - A new mechanism to allow RTC drivers to specify the resolution of the
   RTC so the suspend/resume code can make informed decisions whether to
   inject the suspended time or not in case of fast suspend/resume cycles.

5 files changed, 227 insertions, 183 deletions

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index edf19cc53140..90f84582a076 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -492,6 +492,67 @@ out:
 	return leap;
 }
 
+static void sync_hw_clock(struct work_struct *work);
+static DECLARE_DELAYED_WORK(sync_work, sync_hw_clock);
+
+static void sched_sync_hw_clock(struct timespec64 now,
+				unsigned long target_nsec, bool fail)
+
+{
+	struct timespec64 next;
+
+	getnstimeofday64(&next);
+	if (!fail)
+		next.tv_sec = 659;
+	else {
+		/*
+		 * Try again as soon as possible. Delaying long periods
+		 * decreases the accuracy of the work queue timer. Due to this
+		 * the algorithm is very likely to require a short-sleep retry
+		 * after the above long sleep to synchronize ts_nsec.
+		 */
+		next.tv_sec = 0;
+	}
+
+	/* Compute the needed delay that will get to tv_nsec == target_nsec */
+	next.tv_nsec = target_nsec - next.tv_nsec;
+	if (next.tv_nsec <= 0)
+		next.tv_nsec += NSEC_PER_SEC;
+	if (next.tv_nsec >= NSEC_PER_SEC) {
+		next.tv_sec++;
+		next.tv_nsec -= NSEC_PER_SEC;
+	}
+
+	queue_delayed_work(system_power_efficient_wq, &sync_work,
+			   timespec64_to_jiffies(&next));
+}
+
+static void sync_rtc_clock(void)
+{
+	unsigned long target_nsec;
+	struct timespec64 adjust, now;
+	int rc;
+
+	if (!IS_ENABLED(CONFIG_RTC_SYSTOHC))
+		return;
+
+	getnstimeofday64(&now);
+
+	adjust = now;
+	if (persistent_clock_is_local)
+		adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
+
+	/*
+	 * The current RTC in use will provide the target_nsec it wants to be
+	 * called at, and does rtc_tv_nsec_ok internally.
+	 */
+	rc = rtc_set_ntp_time(adjust, &target_nsec);
+	if (rc == -ENODEV)
+		return;
+
+	sched_sync_hw_clock(now, target_nsec, rc);
+}
+
 #ifdef CONFIG_GENERIC_CMOS_UPDATE
 int __weak update_persistent_clock(struct timespec now)
 {
@@ -507,76 +568,75 @@ int __weak update_persistent_clock64(struct timespec64 now64)
 }
 #endif
 
-#if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC)
-static void sync_cmos_clock(struct work_struct *work);
-
-static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock);
-
-static void sync_cmos_clock(struct work_struct *work)
+static bool sync_cmos_clock(void)
 {
+	static bool no_cmos;
 	struct timespec64 now;
-	struct timespec64 next;
-	int fail = 1;
+	struct timespec64 adjust;
+	int rc = -EPROTO;
+	long target_nsec = NSEC_PER_SEC / 2;
+
+	if (!IS_ENABLED(CONFIG_GENERIC_CMOS_UPDATE))
+		return false;
+
+	if (no_cmos)
+		return false;
 
 	/*
-	 * If we have an externally synchronized Linux clock, then update
-	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
-	 * called as close as possible to 500 ms before the new second starts.
-	 * This code is run on a timer.  If the clock is set, that timer
-	 * may not expire at the correct time.  Thus, we adjust...
-	 * We want the clock to be within a couple of ticks from the target.
+	 * Historically update_persistent_clock64() has followed x86
+	 * semantics, which match the MC146818A/etc RTC. This RTC will store
+	 * 'adjust' and then in .5s it will advance once second.
+	 *
+	 * Architectures are strongly encouraged to use rtclib and not
+	 * implement this legacy API.
 	 */
-	if (!ntp_synced()) {
-		/*
-		 * Not synced, exit, do not restart a timer (if one is
-		 * running, let it run out).
-		 */
-		return;
-	}
-
 	getnstimeofday64(&now);
-	if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec * 5) {
-		struct timespec64 adjust = now;
-
-		fail = -ENODEV;
+	if (rtc_tv_nsec_ok(-1 * target_nsec, &adjust, &now)) {
 		if (persistent_clock_is_local)
 			adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
-#ifdef CONFIG_GENERIC_CMOS_UPDATE
-		fail = update_persistent_clock64(adjust);
-#endif
-
-#ifdef CONFIG_RTC_SYSTOHC
-		if (fail == -ENODEV)
-			fail = rtc_set_ntp_time(adjust);
-#endif
+		rc = update_persistent_clock64(adjust);
+		/*
+		 * The machine does not support update_persistent_clock64 even
+		 * though it defines CONFIG_GENERIC_CMOS_UPDATE.
+		 */
+		if (rc == -ENODEV) {
+			no_cmos = true;
+			return false;
+		}
 	}
 
-	next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
-	if (next.tv_nsec <= 0)
-		next.tv_nsec += NSEC_PER_SEC;
+	sched_sync_hw_clock(now, target_nsec, rc);
+	return true;
+}
 
-	if (!fail || fail == -ENODEV)
-		next.tv_sec = 659;
-	else
-		next.tv_sec = 0;
+/*
+ * If we have an externally synchronized Linux clock, then update RTC clock
+ * accordingly every ~11 minutes. Generally RTCs can only store second
+ * precision, but many RTCs will adjust the phase of their second tick to
+ * match the moment of update. This infrastructure arranges to call to the RTC
+ * set at the correct moment to phase synchronize the RTC second tick over
+ * with the kernel clock.
+ */
+static void sync_hw_clock(struct work_struct *work)
+{
+	if (!ntp_synced())
+		return;
 
-	if (next.tv_nsec >= NSEC_PER_SEC) {
-		next.tv_sec++;
-		next.tv_nsec -= NSEC_PER_SEC;
-	}
-	queue_delayed_work(system_power_efficient_wq,
-			   &sync_cmos_work, timespec64_to_jiffies(&next));
+	if (sync_cmos_clock())
+		return;
+
+	sync_rtc_clock();
 }
 
 void ntp_notify_cmos_timer(void)
 {
-	queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
-}
-
-#else
-void ntp_notify_cmos_timer(void) { }
-#endif
+	if (!ntp_synced())
+		return;
 
+	if (IS_ENABLED(CONFIG_GENERIC_CMOS_UPDATE) ||
+	    IS_ENABLED(CONFIG_RTC_SYSTOHC))
+		queue_delayed_work(system_power_efficient_wq, &sync_work, 0);
+}
 
 /*
  * Propagate a new txc->status value into the NTP state:
@@ -653,67 +713,6 @@ static inline void process_adjtimex_modes(struct timex *txc,
 }
 
 
-
-/**
- * ntp_validate_timex - Ensures the timex is ok for use in do_adjtimex
- */
-int ntp_validate_timex(struct timex *txc)
-{
-	if (txc->modes & ADJ_ADJTIME) {
-		/* singleshot must not be used with any other mode bits */
-		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
-			return -EINVAL;
-		if (!(txc->modes & ADJ_OFFSET_READONLY) &&
-		    !capable(CAP_SYS_TIME))
-			return -EPERM;
-	} else {
-		/* In order to modify anything, you gotta be super-user! */
-		 if (txc->modes && !capable(CAP_SYS_TIME))
-			return -EPERM;
-		/*
-		 * if the quartz is off by more than 10% then
-		 * something is VERY wrong!
-		 */
-		if (txc->modes & ADJ_TICK &&
-		    (txc->tick <  900000/USER_HZ ||
-		     txc->tick > 1100000/USER_HZ))
-			return -EINVAL;
-	}
-
-	if (txc->modes & ADJ_SETOFFSET) {
-		/* In order to inject time, you gotta be super-user! */
-		if (!capable(CAP_SYS_TIME))
-			return -EPERM;
-
-		if (txc->modes & ADJ_NANO) {
-			struct timespec ts;
-
-			ts.tv_sec = txc->time.tv_sec;
-			ts.tv_nsec = txc->time.tv_usec;
-			if (!timespec_inject_offset_valid(&ts))
-				return -EINVAL;
-
-		} else {
-			if (!timeval_inject_offset_valid(&txc->time))
-				return -EINVAL;
-		}
-	}
-
-	/*
-	 * Check for potential multiplication overflows that can
-	 * only happen on 64-bit systems:
-	 */
-	if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
-		if (LLONG_MIN / PPM_SCALE > txc->freq)
-			return -EINVAL;
-		if (LLONG_MAX / PPM_SCALE < txc->freq)
-			return -EINVAL;
-	}
-
-	return 0;
-}
-
-
 /*
  * adjtimex mainly allows reading (and writing, if superuser) of
  * kernel time-keeping variables. used by xntpd.
diff --git a/kernel/time/ntp_internal.h b/kernel/time/ntp_internal.h
index d8a7c11fa71a..74b52cd48209 100644
--- a/kernel/time/ntp_internal.h
+++ b/kernel/time/ntp_internal.h
@@ -7,7 +7,6 @@ extern void ntp_clear(void);
 extern u64 ntp_tick_length(void);
 extern ktime_t ntp_get_next_leap(void);
 extern int second_overflow(time64_t secs);
-extern int ntp_validate_timex(struct timex *);
 extern int __do_adjtimex(struct timex *, struct timespec64 *, s32 *);
 extern void __hardpps(const struct timespec64 *, const struct timespec64 *);
 #endif /* _LINUX_NTP_INTERNAL_H */
diff --git a/kernel/time/time.c b/kernel/time/time.c
index cfe3d3e4679f..bd4e6c7dd689 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -158,40 +158,6 @@ SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
 }
 
 /*
- * Indicates if there is an offset between the system clock and the hardware
- * clock/persistent clock/rtc.
- */
-int persistent_clock_is_local;
-
-/*
- * Adjust the time obtained from the CMOS to be UTC time instead of
- * local time.
- *
- * This is ugly, but preferable to the alternatives.  Otherwise we
- * would either need to write a program to do it in /etc/rc (and risk
- * confusion if the program gets run more than once; it would also be
- * hard to make the program warp the clock precisely n hours)  or
- * compile in the timezone information into the kernel.  Bad, bad....
- *
- *						- TYT, 1992-01-01
- *
- * The best thing to do is to keep the CMOS clock in universal time (UTC)
- * as real UNIX machines always do it. This avoids all headaches about
- * daylight saving times and warping kernel clocks.
- */
-static inline void warp_clock(void)
-{
-	if (sys_tz.tz_minuteswest != 0) {
-		struct timespec adjust;
-
-		persistent_clock_is_local = 1;
-		adjust.tv_sec = sys_tz.tz_minuteswest * 60;
-		adjust.tv_nsec = 0;
-		timekeeping_inject_offset(&adjust);
-	}
-}
-
-/*
  * In case for some reason the CMOS clock has not already been running
  * in UTC, but in some local time: The first time we set the timezone,
  * we will warp the clock so that it is ticking UTC time instead of
@@ -224,7 +190,7 @@ int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz
 		if (firsttime) {
 			firsttime = 0;
 			if (!tv)
-				warp_clock();
+				timekeeping_warp_clock();
 		}
 	}
 	if (tv)
@@ -441,6 +407,7 @@ time64_t mktime64(const unsigned int year0, const unsigned int mon0,
 }
 EXPORT_SYMBOL(mktime64);
 
+#if __BITS_PER_LONG == 32
 /**
  * set_normalized_timespec - set timespec sec and nsec parts and normalize
  *
@@ -501,6 +468,7 @@ struct timespec ns_to_timespec(const s64 nsec)
 	return ts;
 }
 EXPORT_SYMBOL(ns_to_timespec);
+#endif
 
 /**
  * ns_to_timeval - Convert nanoseconds to timeval
@@ -520,7 +488,6 @@ struct timeval ns_to_timeval(const s64 nsec)
 }
 EXPORT_SYMBOL(ns_to_timeval);
 
-#if BITS_PER_LONG == 32
 /**
  * set_normalized_timespec - set timespec sec and nsec parts and normalize
  *
@@ -581,7 +548,7 @@ struct timespec64 ns_to_timespec64(const s64 nsec)
 	return ts;
 }
 EXPORT_SYMBOL(ns_to_timespec64);
-#endif
+
 /**
  * msecs_to_jiffies: - convert milliseconds to jiffies
  * @m:	time in milliseconds
@@ -853,24 +820,6 @@ unsigned long nsecs_to_jiffies(u64 n)
 EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
 
 /*
- * Add two timespec values and do a safety check for overflow.
- * It's assumed that both values are valid (>= 0)
- */
-struct timespec timespec_add_safe(const struct timespec lhs,
-				  const struct timespec rhs)
-{
-	struct timespec res;
-
-	set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec,
-				lhs.tv_nsec + rhs.tv_nsec);
-
-	if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)
-		res.tv_sec = TIME_T_MAX;
-
-	return res;
-}
-
-/*
  * Add two timespec64 values and do a safety check for overflow.
  * It's assumed that both values are valid (>= 0).
  * And, each timespec64 is in normalized form.
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 8af77006e937..353f7bd1eeb0 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1306,33 +1306,31 @@ EXPORT_SYMBOL(do_settimeofday64);
  *
  * Adds or subtracts an offset value from the current time.
  */
-int timekeeping_inject_offset(struct timespec *ts)
+static int timekeeping_inject_offset(struct timespec64 *ts)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned long flags;
-	struct timespec64 ts64, tmp;
+	struct timespec64 tmp;
 	int ret = 0;
 
-	if (!timespec_inject_offset_valid(ts))
+	if (ts->tv_nsec < 0 || 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_compare(&tk->wall_to_monotonic, &ts64) > 0 ||
+	tmp = timespec64_add(tk_xtime(tk), *ts);
+	if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
 	    !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));
+	tk_xtime_add(tk, ts);
+	tk_set_wall_to_mono(tk, timespec64_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);
@@ -1345,7 +1343,40 @@ error: /* even if we error out, we forwarded the time, so call update */
 
 	return ret;
 }
-EXPORT_SYMBOL(timekeeping_inject_offset);
+
+/*
+ * Indicates if there is an offset between the system clock and the hardware
+ * clock/persistent clock/rtc.
+ */
+int persistent_clock_is_local;
+
+/*
+ * Adjust the time obtained from the CMOS to be UTC time instead of
+ * local time.
+ *
+ * This is ugly, but preferable to the alternatives.  Otherwise we
+ * would either need to write a program to do it in /etc/rc (and risk
+ * confusion if the program gets run more than once; it would also be
+ * hard to make the program warp the clock precisely n hours)  or
+ * compile in the timezone information into the kernel.  Bad, bad....
+ *
+ *						- TYT, 1992-01-01
+ *
+ * The best thing to do is to keep the CMOS clock in universal time (UTC)
+ * as real UNIX machines always do it. This avoids all headaches about
+ * daylight saving times and warping kernel clocks.
+ */
+void timekeeping_warp_clock(void)
+{
+	if (sys_tz.tz_minuteswest != 0) {
+		struct timespec64 adjust;
+
+		persistent_clock_is_local = 1;
+		adjust.tv_sec = sys_tz.tz_minuteswest * 60;
+		adjust.tv_nsec = 0;
+		timekeeping_inject_offset(&adjust);
+	}
+}
 
 /**
  * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
@@ -2290,6 +2321,72 @@ ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
 }
 
 /**
+ * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
+ */
+static int timekeeping_validate_timex(struct timex *txc)
+{
+	if (txc->modes & ADJ_ADJTIME) {
+		/* singleshot must not be used with any other mode bits */
+		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
+			return -EINVAL;
+		if (!(txc->modes & ADJ_OFFSET_READONLY) &&
+		    !capable(CAP_SYS_TIME))
+			return -EPERM;
+	} else {
+		/* In order to modify anything, you gotta be super-user! */
+		if (txc->modes && !capable(CAP_SYS_TIME))
+			return -EPERM;
+		/*
+		 * if the quartz is off by more than 10% then
+		 * something is VERY wrong!
+		 */
+		if (txc->modes & ADJ_TICK &&
+		    (txc->tick <  900000/USER_HZ ||
+		     txc->tick > 1100000/USER_HZ))
+			return -EINVAL;
+	}
+
+	if (txc->modes & ADJ_SETOFFSET) {
+		/* In order to inject time, you gotta be super-user! */
+		if (!capable(CAP_SYS_TIME))
+			return -EPERM;
+
+		/*
+		 * Validate if a timespec/timeval used to inject a time
+		 * offset is valid.  Offsets can be postive or negative, so
+		 * we don't check tv_sec. The value of the timeval/timespec
+		 * is the sum of its fields,but *NOTE*:
+		 * The field tv_usec/tv_nsec must always be non-negative and
+		 * we can't have more nanoseconds/microseconds than a second.
+		 */
+		if (txc->time.tv_usec < 0)
+			return -EINVAL;
+
+		if (txc->modes & ADJ_NANO) {
+			if (txc->time.tv_usec >= NSEC_PER_SEC)
+				return -EINVAL;
+		} else {
+			if (txc->time.tv_usec >= USEC_PER_SEC)
+				return -EINVAL;
+		}
+	}
+
+	/*
+	 * Check for potential multiplication overflows that can
+	 * only happen on 64-bit systems:
+	 */
+	if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
+		if (LLONG_MIN / PPM_SCALE > txc->freq)
+			return -EINVAL;
+		if (LLONG_MAX / PPM_SCALE < txc->freq)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+/**
  * do_adjtimex() - Accessor function to NTP __do_adjtimex function
  */
 int do_adjtimex(struct timex *txc)
@@ -2301,12 +2398,12 @@ int do_adjtimex(struct timex *txc)
 	int ret;
 
 	/* Validate the data before disabling interrupts */
-	ret = ntp_validate_timex(txc);
+	ret = timekeeping_validate_timex(txc);
 	if (ret)
 		return ret;
 
 	if (txc->modes & ADJ_SETOFFSET) {
-		struct timespec delta;
+		struct timespec64 delta;
 		delta.tv_sec  = txc->time.tv_sec;
 		delta.tv_nsec = txc->time.tv_usec;
 		if (!(txc->modes & ADJ_NANO))
diff --git a/kernel/time/timekeeping.h b/kernel/time/timekeeping.h
index d0914676d4c5..44aec7893cdd 100644
--- a/kernel/time/timekeeping.h
+++ b/kernel/time/timekeeping.h
@@ -10,7 +10,7 @@ extern ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq,
 
 extern int timekeeping_valid_for_hres(void);
 extern u64 timekeeping_max_deferment(void);
-extern int timekeeping_inject_offset(struct timespec *ts);
+extern void timekeeping_warp_clock(void);
 extern int timekeeping_suspend(void);
 extern void timekeeping_resume(void);