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

Pull timer updates from Thomas Gleixner:
 "A rather smalish set of updates for timers and timekeeping:

   - Two core fixes to prevent potential undefinded behaviour about
     which gcc is complaining rightfully.

   - A fix to prevent stopping the tick on an (soon) offline CPU so it
     can complete the shutdown procedure.

   - Wait for clocks to stabilize before making decisions, so a not yet
     validated clock is not rejected.

   - The usual pile of fixes to the various clocksource drivers.

   - Core code typo and include fixlets"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Include the correct header for errno definitions
  clocksource/drivers/ti-32k: Prevent ftrace recursion
  clocksource/mips-gic-timer: Stop checking cpu_has_counter
  clocksource/mips-gic-timer: Print an error if IRQ setup fails
  tick/nohz: Prevent stopping the tick on an offline CPU
  clocksource/drivers/oxnas: Add OX820 compatible
  clocksource/drivers/timer-atmel-pit: Simplify IRQ handler
  clocksource/drivers/timer-atmel-pit: Remove uselesss WARN_ON_ONCE
  clocksource/drivers/timer-atmel-pit: Drop at91sam926x_pit_common_init
  clocksource/drivers/moxart: Replace panic by pr_err
  clocksource/drivers/moxart: Replace setup_irq by request_irq
  clocksource/drivers/moxart: Add Aspeed support
  clocksource/drivers/moxart: Use struct to hold state
  clocksource/drivers/moxart: Refactor enable/disable
  time: Avoid undefined behaviour in ktime_add_safe()
  time: Avoid undefined behaviour in timespec64_add_safe()
  timekeeping: Prints the amounts of time spent during suspend
  clocksource: Defer override invalidation unless clock is unstable
  hrtimer: Spelling fixes

kernel/time/clocksource.c

@@ -600,9 +600,18 @@ static void __clocksource_select(bool skipcur)
 		 */
 		if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) {
 			/* Override clocksource cannot be used. */
-			pr_warn("Override clocksource %s is not HRT compatible - cannot switch while in HRT/NOHZ mode\n",
-				cs->name);
-			override_name[0] = 0;
+			if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+				pr_warn("Override clocksource %s is unstable and not HRT compatible - cannot switch while in HRT/NOHZ mode\n",
+					cs->name);
+				override_name[0] = 0;
+			} else {
+				/*
+				 * The override cannot be currently verified.
+				 * Deferring to let the watchdog check.
+				 */
+				pr_info("Override clocksource %s is not currently HRT compatible - deferring\n",
+					cs->name);
+			}
 		} else
 			/* Override clocksource can be used. */
 			best = cs;

kernel/time/hrtimer.c

@@ -307,7 +307,7 @@ EXPORT_SYMBOL_GPL(__ktime_divns);
  */
 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
 {
-	ktime_t res = ktime_add(lhs, rhs);
+	ktime_t res = ktime_add_unsafe(lhs, rhs);
 
 	/*
 	 * We use KTIME_SEC_MAX here, the maximum timeout which we can
@@ -703,7 +703,7 @@ static void clock_was_set_work(struct work_struct *work)
 static DECLARE_WORK(hrtimer_work, clock_was_set_work);
 
 /*
- * Called from timekeeping and resume code to reprogramm the hrtimer
+ * Called from timekeeping and resume code to reprogram the hrtimer
  * interrupt device on all cpus.
  */
 void clock_was_set_delayed(void)
@@ -1241,7 +1241,7 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
 
 	/*
 	 * Note: We clear the running state after enqueue_hrtimer and
-	 * we do not reprogramm the event hardware. Happens either in
+	 * we do not reprogram the event hardware. Happens either in
 	 * hrtimer_start_range_ns() or in hrtimer_interrupt()
 	 *
 	 * Note: Because we dropped the cpu_base->lock above,

kernel/time/tick-sched.c

@@ -186,10 +186,13 @@ static bool check_tick_dependency(atomic_t *dep)
 	return false;
 }
 
-static bool can_stop_full_tick(struct tick_sched *ts)
+static bool can_stop_full_tick(int cpu, struct tick_sched *ts)
 {
 	WARN_ON_ONCE(!irqs_disabled());
 
+	if (unlikely(!cpu_online(cpu)))
+		return false;
+
 	if (check_tick_dependency(&tick_dep_mask))
 		return false;
 
@@ -843,7 +846,7 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts)
 	if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
 		return;
 
-	if (can_stop_full_tick(ts))
+	if (can_stop_full_tick(cpu, ts))
 		tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
 	else if (ts->tick_stopped)
 		tick_nohz_restart_sched_tick(ts, ktime_get());

kernel/time/time.c

@@ -780,7 +780,7 @@ struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
 {
 	struct timespec64 res;
 
-	set_normalized_timespec64(&res, lhs.tv_sec + rhs.tv_sec,
+	set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
 			lhs.tv_nsec + rhs.tv_nsec);
 
 	if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {

kernel/time/timekeeping_debug.c

@@ -75,5 +75,7 @@ void tk_debug_account_sleep_time(struct timespec64 *t)
 	int bin = min(fls(t->tv_sec), NUM_BINS-1);
 
 	sleep_time_bin[bin]++;
+	pr_info("Suspended for %lld.%03lu seconds\n", (s64)t->tv_sec,
+			t->tv_nsec / NSEC_PER_MSEC);
 }