Merge tag 'timers-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer core updates from Thomas Gleixner:

 - Inline timecounter_cyc2time() as that is now used in the networking
   hotpath. Inlining it significantly improves performance.

 - Optimize the tick dependency check in case that the tracepoint is
   disabled, which improves the hotpath performance in the tick
   management code, which is a hotpath on transitions in and out of
   idle.

 - The usual cleanups and improvements

* tag 'timers-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time/kunit: Document handling of negative years of is_leap()
  tick/nohz: Optimize check_tick_dependency() with early return
  time/sched_clock: Use ACCESS_PRIVATE() to evaluate hrtimer::function
  hrtimer: Drop _tv64() helpers
  hrtimer: Remove public definition of HIGH_RES_NSEC
  hrtimer: Remove unused resolution constants
  time/timecounter: Inline timecounter_cyc2time()

5 files changed, 18 insertions, 40 deletions

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 59d22f1bd0a8..860af7a58428 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -50,6 +50,14 @@
 #include "tick-internal.h"
 
 /*
+ * The resolution of the clocks. The resolution value is returned in
+ * the clock_getres() system call to give application programmers an
+ * idea of the (in)accuracy of timers. Timer values are rounded up to
+ * this resolution values.
+ */
+#define HIGH_RES_NSEC		1
+
+/*
  * Masks for selecting the soft and hard context timers from
  * cpu_base->active
  */
@@ -806,7 +814,7 @@ static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)
 	struct hrtimer_clock_base *base = timer->base;
 	ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
 
-	WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
+	WARN_ON_ONCE(hrtimer_get_expires(timer) < 0);
 
 	/*
 	 * CLOCK_REALTIME timer might be requested with an absolute
@@ -1053,7 +1061,7 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
 
 		orun = ktime_divns(delta, incr);
 		hrtimer_add_expires_ns(timer, incr * orun);
-		if (hrtimer_get_expires_tv64(timer) > now)
+		if (hrtimer_get_expires(timer) > now)
 			return orun;
 		/*
 		 * This (and the ktime_add() below) is the
@@ -1835,7 +1843,7 @@ static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now,
 			 * are right-of a not yet expired timer, because that
 			 * timer will have to trigger a wakeup anyway.
 			 */
-			if (basenow < hrtimer_get_softexpires_tv64(timer))
+			if (basenow < hrtimer_get_softexpires(timer))
 				break;
 
 			__run_hrtimer(cpu_base, base, timer, &basenow, flags);
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index f39111830ca3..f3aaef695b8c 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -215,7 +215,7 @@ void sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
 
 	update_clock_read_data(&rd);
 
-	if (sched_clock_timer.function != NULL) {
+	if (ACCESS_PRIVATE(&sched_clock_timer, function) != NULL) {
 		/* update timeout for clock wrap */
 		hrtimer_start(&sched_clock_timer, cd.wrap_kt,
 			      HRTIMER_MODE_REL_HARD);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 72e39c793117..f7907fadd63f 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -344,6 +344,9 @@ static bool check_tick_dependency(atomic_t *dep)
 {
 	int val = atomic_read(dep);
 
+	if (likely(!tracepoint_enabled(tick_stop)))
+		return !val;
+
 	if (val & TICK_DEP_MASK_POSIX_TIMER) {
 		trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);
 		return true;
diff --git a/kernel/time/time_test.c b/kernel/time/time_test.c
index 2889763165e5..1b99180da288 100644
--- a/kernel/time/time_test.c
+++ b/kernel/time/time_test.c
@@ -4,7 +4,9 @@
 #include <linux/time.h>
 
 /*
- * Traditional implementation of leap year evaluation.
+ * Traditional implementation of leap year evaluation, but note that long
+ * is a signed type and the tests do cover negative year values. So this
+ * can't use the is_leap_year() helper from rtc.h.
  */
 static bool is_leap(long year)
 {
diff --git a/kernel/time/timecounter.c b/kernel/time/timecounter.c
index 3d2a354cfe1c..2e64dbb6302d 100644
--- a/kernel/time/timecounter.c
+++ b/kernel/time/timecounter.c
@@ -62,38 +62,3 @@ u64 timecounter_read(struct timecounter *tc)
 }
 EXPORT_SYMBOL_GPL(timecounter_read);
 
-/*
- * This is like cyclecounter_cyc2ns(), but it is used for computing a
- * time previous to the time stored in the cycle counter.
- */
-static u64 cc_cyc2ns_backwards(const struct cyclecounter *cc,
-			       u64 cycles, u64 mask, u64 frac)
-{
-	u64 ns = (u64) cycles;
-
-	ns = ((ns * cc->mult) - frac) >> cc->shift;
-
-	return ns;
-}
-
-u64 timecounter_cyc2time(const struct timecounter *tc,
-			 u64 cycle_tstamp)
-{
-	u64 delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask;
-	u64 nsec = tc->nsec, frac = tc->frac;
-
-	/*
-	 * Instead of always treating cycle_tstamp as more recent
-	 * than tc->cycle_last, detect when it is too far in the
-	 * future and treat it as old time stamp instead.
-	 */
-	if (delta > tc->cc->mask / 2) {
-		delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask;
-		nsec -= cc_cyc2ns_backwards(tc->cc, delta, tc->mask, frac);
-	} else {
-		nsec += cyclecounter_cyc2ns(tc->cc, delta, tc->mask, &frac);
-	}
-
-	return nsec;
-}
-EXPORT_SYMBOL_GPL(timecounter_cyc2time);