Merge tag 'timers-core-2024-05-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timers and timekeeping updates from Thomas Gleixner:
 "Core code:

   - Make timekeeping and VDSO time readouts resilent against math
     overflow:

     In guest context the kernel is prone to math overflow when the host
     defers the timer interrupt due to overload, malfunction or malice.

     This can be mitigated by checking the clocksource delta for the
     maximum deferrement which is readily available. If that value is
     exceeded then the code uses a slowpath function which can handle
     the multiplication overflow.

     This functionality is enabled unconditionally in the kernel, but
     made conditional in the VDSO code. The latter is conditional
     because it allows architectures to optimize the check so it is not
     causing performance regressions.

     On X86 this is achieved by reworking the existing check for
     negative TSC deltas as a negative delta obviously exceeds the
     maximum deferrement when it is evaluated as an unsigned value. That
     avoids two conditionals in the hotpath and allows to hide both the
     negative delta and the large delta handling in the same slow path.

   - Add an initial minimal ktime_t abstraction for Rust

   - The usual boring cleanups and enhancements

  Drivers:

   - Boring updates to device trees and trivial enhancements in various
     drivers"

* tag 'timers-core-2024-05-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  clocksource/drivers/arm_arch_timer: Mark hisi_161010101_oem_info const
  clocksource/drivers/timer-ti-dm: Remove an unused field in struct dmtimer
  clocksource/drivers/renesas-ostm: Avoid reprobe after successful early probe
  clocksource/drivers/renesas-ostm: Allow OSTM driver to reprobe for RZ/V2H(P) SoC
  dt-bindings: timer: renesas: ostm: Document Renesas RZ/V2H(P) SoC
  rust: time: doc: Add missing C header links
  clocksource: Make the int help prompt unit readable in ncurses
  hrtimer: Rename __hrtimer_hres_active() to hrtimer_hres_active()
  timerqueue: Remove never used function timerqueue_node_expires()
  rust: time: Add Ktime
  vdso: Fix powerpc build U64_MAX undeclared error
  clockevents: Convert s[n]printf() to sysfs_emit()
  clocksource: Convert s[n]printf() to sysfs_emit()
  clocksource: Make watchdog and suspend-timing multiplication overflow safe
  timekeeping: Let timekeeping_cycles_to_ns() handle both under and overflow
  timekeeping: Make delta calculation overflow safe
  timekeeping: Prepare timekeeping_cycles_to_ns() for overflow safety
  timekeeping: Fold in timekeeping_delta_to_ns()
  timekeeping: Consolidate timekeeping helpers
  timekeeping: Refactor timekeeping helpers
  ...

1 files changed, 9 insertions, 32 deletions

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 70625dff62ce..492c14aac642 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -644,17 +644,12 @@ static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
 /*
  * Is the high resolution mode active ?
  */
-static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
+static inline int hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
 {
 	return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
 		cpu_base->hres_active : 0;
 }
 
-static inline int hrtimer_hres_active(void)
-{
-	return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
-}
-
 static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base,
 				struct hrtimer *next_timer,
 				ktime_t expires_next)
@@ -678,7 +673,7 @@ static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base,
 	 * set. So we'd effectively block all timers until the T2 event
 	 * fires.
 	 */
-	if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
+	if (!hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
 		return;
 
 	tick_program_event(expires_next, 1);
@@ -789,12 +784,12 @@ static void retrigger_next_event(void *arg)
 	 * function call will take care of the reprogramming in case the
 	 * CPU was in a NOHZ idle sleep.
 	 */
-	if (!__hrtimer_hres_active(base) && !tick_nohz_active)
+	if (!hrtimer_hres_active(base) && !tick_nohz_active)
 		return;
 
 	raw_spin_lock(&base->lock);
 	hrtimer_update_base(base);
-	if (__hrtimer_hres_active(base))
+	if (hrtimer_hres_active(base))
 		hrtimer_force_reprogram(base, 0);
 	else
 		hrtimer_update_next_event(base);
@@ -951,7 +946,7 @@ void clock_was_set(unsigned int bases)
 	cpumask_var_t mask;
 	int cpu;
 
-	if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active)
+	if (!hrtimer_hres_active(cpu_base) && !tick_nohz_active)
 		goto out_timerfd;
 
 	if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
@@ -1491,7 +1486,7 @@ u64 hrtimer_get_next_event(void)
 
 	raw_spin_lock_irqsave(&cpu_base->lock, flags);
 
-	if (!__hrtimer_hres_active(cpu_base))
+	if (!hrtimer_hres_active(cpu_base))
 		expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL);
 
 	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
@@ -1514,7 +1509,7 @@ u64 hrtimer_next_event_without(const struct hrtimer *exclude)
 
 	raw_spin_lock_irqsave(&cpu_base->lock, flags);
 
-	if (__hrtimer_hres_active(cpu_base)) {
+	if (hrtimer_hres_active(cpu_base)) {
 		unsigned int active;
 
 		if (!cpu_base->softirq_activated) {
@@ -1875,25 +1870,7 @@ retry:
 	tick_program_event(expires_next, 1);
 	pr_warn_once("hrtimer: interrupt took %llu ns\n", ktime_to_ns(delta));
 }
-
-/* called with interrupts disabled */
-static inline void __hrtimer_peek_ahead_timers(void)
-{
-	struct tick_device *td;
-
-	if (!hrtimer_hres_active())
-		return;
-
-	td = this_cpu_ptr(&tick_cpu_device);
-	if (td && td->evtdev)
-		hrtimer_interrupt(td->evtdev);
-}
-
-#else /* CONFIG_HIGH_RES_TIMERS */
-
-static inline void __hrtimer_peek_ahead_timers(void) { }
-
-#endif	/* !CONFIG_HIGH_RES_TIMERS */
+#endif /* !CONFIG_HIGH_RES_TIMERS */
 
 /*
  * Called from run_local_timers in hardirq context every jiffy
@@ -1904,7 +1881,7 @@ void hrtimer_run_queues(void)
 	unsigned long flags;
 	ktime_t now;
 
-	if (__hrtimer_hres_active(cpu_base))
+	if (hrtimer_hres_active(cpu_base))
 		return;
 
 	/*