Merge branch 'fortglx/4.5/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

Get the core time(keeping) updates from John Stultz

    - NTP robustness tweaks
    - Another signed overflow nailed down
    - More y2038 changes
    - Stop alarmtimer after resume
    - MAINTAINERS update
    - Selftest fixes

MAINTAINERS

@@ -9348,7 +9348,7 @@ M:	Andreas Noever <andreas.noever@gmail.com>
 S:	Maintained
 F:	drivers/thunderbolt/
 
-TIMEKEEPING, CLOCKSOURCE CORE, NTP
+TIMEKEEPING, CLOCKSOURCE CORE, NTP, ALARMTIMER
 M:	John Stultz <john.stultz@linaro.org>
 M:	Thomas Gleixner <tglx@linutronix.de>
 L:	linux-kernel@vger.kernel.org
@@ -9361,6 +9361,7 @@ F:	include/uapi/linux/time.h
 F:	include/uapi/linux/timex.h
 F:	kernel/time/clocksource.c
 F:	kernel/time/time*.c
+F:	kernel/time/alarmtimer.c
 F:	kernel/time/ntp.c
 F:	tools/testing/selftests/timers/
 

include/linux/time.h

@@ -125,6 +125,32 @@ static inline bool timeval_valid(const struct timeval *tv)
 
 extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
 
+/*
+ * Validates if a timespec/timeval used to inject a time offset is valid.
+ * Offsets can be postive or negative. 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.
+ */
+static inline bool timeval_inject_offset_valid(const struct timeval *tv)
+{
+	/* We don't check the tv_sec as it can be positive or negative */
+
+	/* Can't have more microseconds then a second */
+	if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
+		return false;
+	return true;
+}
+
+static inline bool timespec_inject_offset_valid(const struct timespec *ts)
+{
+	/* We don't check the tv_sec as it can be positive or negative */
+
+	/* Can't have more nanoseconds then a second */
+	if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
+		return false;
+	return true;
+}
+
 #define CURRENT_TIME		(current_kernel_time())
 #define CURRENT_TIME_SEC	((struct timespec) { get_seconds(), 0 })
 

kernel/time/alarmtimer.c

@@ -271,11 +271,27 @@ static int alarmtimer_suspend(struct device *dev)
 		__pm_wakeup_event(ws, MSEC_PER_SEC);
 	return ret;
 }
+
+static int alarmtimer_resume(struct device *dev)
+{
+	struct rtc_device *rtc;
+
+	rtc = alarmtimer_get_rtcdev();
+	if (rtc)
+		rtc_timer_cancel(rtc, &rtctimer);
+	return 0;
+}
+
 #else
 static int alarmtimer_suspend(struct device *dev)
 {
 	return 0;
 }
+
+static int alarmtimer_resume(struct device *dev)
+{
+	return 0;
+}
 #endif
 
 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
@@ -800,6 +816,7 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 /* Suspend hook structures */
 static const struct dev_pm_ops alarmtimer_pm_ops = {
 	.suspend = alarmtimer_suspend,
+	.resume = alarmtimer_resume,
 };
 
 static struct platform_driver alarmtimer_driver = {

kernel/time/clocksource.c

@@ -218,8 +218,8 @@ static void clocksource_watchdog(unsigned long data)
 
 		/* Check the deviation from the watchdog clocksource. */
 		if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
-			pr_warn("timekeeping watchdog: Marking clocksource '%s' as unstable because the skew is too large:\n",
-				cs->name);
+			pr_warn("timekeeping watchdog on CPU%d: Marking clocksource '%s' as unstable because the skew is too large:\n",
+				smp_processor_id(), cs->name);
 			pr_warn("                      '%s' wd_now: %llx wd_last: %llx mask: %llx\n",
 				watchdog->name, wdnow, wdlast, watchdog->mask);
 			pr_warn("                      '%s' cs_now: %llx cs_last: %llx mask: %llx\n",

kernel/time/ntp.c

@@ -16,8 +16,11 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/rtc.h>
+#include <linux/math64.h>
 
 #include "ntp_internal.h"
+#include "timekeeping_internal.h"
+
 
 /*
  * NTP timekeeping variables:
@@ -70,7 +73,7 @@ static long			time_esterror = NTP_PHASE_LIMIT;
 static s64			time_freq;
 
 /* time at last adjustment (secs):					*/
-static long			time_reftime;
+static time64_t		time_reftime;
 
 static long			time_adjust;
 
@@ -297,25 +300,27 @@ static void ntp_update_offset(long offset)
 	if (!(time_status & STA_PLL))
 		return;
 
-	if (!(time_status & STA_NANO))
+	if (!(time_status & STA_NANO)) {
+		/* Make sure the multiplication below won't overflow */
+		offset = clamp(offset, -USEC_PER_SEC, USEC_PER_SEC);
 		offset *= NSEC_PER_USEC;
+	}
 
 	/*
 	 * Scale the phase adjustment and
 	 * clamp to the operating range.
 	 */
-	offset = min(offset, MAXPHASE);
-	offset = max(offset, -MAXPHASE);
+	offset = clamp(offset, -MAXPHASE, MAXPHASE);
 
 	/*
 	 * Select how the frequency is to be controlled
 	 * and in which mode (PLL or FLL).
 	 */
-	secs = get_seconds() - time_reftime;
+	secs = (long)(__ktime_get_real_seconds() - time_reftime);
 	if (unlikely(time_status & STA_FREQHOLD))
 		secs = 0;
 
-	time_reftime = get_seconds();
+	time_reftime = __ktime_get_real_seconds();
 
 	offset64    = offset;
 	freq_adj    = ntp_update_offset_fll(offset64, secs);
@@ -390,10 +395,11 @@ ktime_t ntp_get_next_leap(void)
  *
  * Also handles leap second processing, and returns leap offset
  */
-int second_overflow(unsigned long secs)
+int second_overflow(time64_t secs)
 {
 	s64 delta;
 	int leap = 0;
+	s32 rem;
 
 	/*
 	 * Leap second processing. If in leap-insert state at the end of the
@@ -404,19 +410,19 @@ int second_overflow(unsigned long secs)
 	case TIME_OK:
 		if (time_status & STA_INS) {
 			time_state = TIME_INS;
-			ntp_next_leap_sec = secs + SECS_PER_DAY -
-						(secs % SECS_PER_DAY);
+			div_s64_rem(secs, SECS_PER_DAY, &rem);
+			ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
 		} else if (time_status & STA_DEL) {
 			time_state = TIME_DEL;
-			ntp_next_leap_sec = secs + SECS_PER_DAY -
-						 ((secs+1) % SECS_PER_DAY);
+			div_s64_rem(secs + 1, SECS_PER_DAY, &rem);
+			ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
 		}
 		break;
 	case TIME_INS:
 		if (!(time_status & STA_INS)) {
 			ntp_next_leap_sec = TIME64_MAX;
 			time_state = TIME_OK;
-		} else if (secs % SECS_PER_DAY == 0) {
+		} else if (secs == ntp_next_leap_sec) {
 			leap = -1;
 			time_state = TIME_OOP;
 			printk(KERN_NOTICE
@@ -427,7 +433,7 @@ int second_overflow(unsigned long secs)
 		if (!(time_status & STA_DEL)) {
 			ntp_next_leap_sec = TIME64_MAX;
 			time_state = TIME_OK;
-		} else if ((secs + 1) % SECS_PER_DAY == 0) {
+		} else if (secs == ntp_next_leap_sec) {
 			leap = 1;
 			ntp_next_leap_sec = TIME64_MAX;
 			time_state = TIME_WAIT;
@@ -590,7 +596,7 @@ static inline void process_adj_status(struct timex *txc, struct timespec64 *ts)
 	 * reference time to current time.
 	 */
 	if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
-		time_reftime = get_seconds();
+		time_reftime = __ktime_get_real_seconds();
 
 	/* only set allowed bits */
 	time_status &= STA_RONLY;
@@ -674,9 +680,15 @@ int ntp_validate_timex(struct timex *txc)
 			return -EINVAL;
 	}
 
-	if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME)))
+	if (txc->modes & ADJ_SETOFFSET) {
+		/* In order to inject time, you gotta be super-user! */
+		if (!capable(CAP_SYS_TIME))
 			return -EPERM;
 
+		if (!timeval_inject_offset_valid(&txc->time))
+			return -EINVAL;
+	}
+
 	/*
 	 * Check for potential multiplication overflows that can
 	 * only happen on 64-bit systems:

kernel/time/ntp_internal.h

@@ -6,7 +6,7 @@ extern void ntp_clear(void);
 /* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
 extern u64 ntp_tick_length(void);
 extern ktime_t ntp_get_next_leap(void);
-extern int second_overflow(unsigned long secs);
+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 *);

kernel/time/timekeeping.c

@@ -305,8 +305,7 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
 
 	delta = timekeeping_get_delta(tkr);
 
-	nsec = delta * tkr->mult + tkr->xtime_nsec;
-	nsec >>= tkr->shift;
+	nsec = (delta * tkr->mult + tkr->xtime_nsec) >> tkr->shift;
 
 	/* If arch requires, add in get_arch_timeoffset() */
 	return nsec + arch_gettimeoffset();
@@ -846,6 +845,19 @@ time64_t ktime_get_real_seconds(void)
 }
 EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
 
+/**
+ * __ktime_get_real_seconds - The same as ktime_get_real_seconds
+ * but without the sequence counter protect. This internal function
+ * is called just when timekeeping lock is already held.
+ */
+time64_t __ktime_get_real_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	return tk->xtime_sec;
+}
+
+
 #ifdef CONFIG_NTP_PPS
 
 /**
@@ -959,7 +971,7 @@ int timekeeping_inject_offset(struct timespec *ts)
 	struct timespec64 ts64, tmp;
 	int ret = 0;
 
-	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
+	if (!timespec_inject_offset_valid(ts))
 		return -EINVAL;
 
 	ts64 = timespec_to_timespec64(*ts);
@@ -1592,9 +1604,12 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
 {
 	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;
+	u32 adj_scale;
 
 	/* Remove any current error adj from freq calculation */
 	if (tk->ntp_err_mult)
@@ -1613,13 +1628,33 @@ static __always_inline void timekeeping_freqadjust(struct timekeeper *tk,
 	/* preserve the direction of correction */
 	negative = (tick_error < 0);
 
-	/* Sort out the magnitude of the correction */
+	/* 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.
+	 */
+	adj_scale = 0;
 	tick_error = abs(tick_error);
-	for (adj = 0; tick_error > interval; adj++)
+	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;
+	}
 
 	/* scale the corrections */
-	timekeeping_apply_adjustment(tk, offset, negative, adj);
+	timekeeping_apply_adjustment(tk, offset, negative, adj_scale);
 }
 
 /*

kernel/time/timekeeping_internal.h

@@ -26,4 +26,6 @@ static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)
 }
 #endif
 
+extern time64_t __ktime_get_real_seconds(void);
+
 #endif /* _TIMEKEEPING_INTERNAL_H */

tools/testing/selftests/timers/clocksource-switch.c

@@ -97,7 +97,7 @@ int get_cur_clocksource(char *buf, size_t size)
 int change_clocksource(char *clocksource)
 {
 	int fd;
-	size_t size;
+	ssize_t size;
 
 	fd = open("/sys/devices/system/clocksource/clocksource0/current_clocksource", O_WRONLY);