hrtimer: Remove hrtimer_clock_base:: Get_time

The get_time() callbacks always need to match the bases clockid.
Instead of maintaining that association twice in hrtimer_bases,
use a helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250821-hrtimer-cleanup-get_time-v2-8-3ae822e5bfbd@linutronix.de

Author: t-8ch

include/linux/hrtimer.h

@@ -154,10 +154,7 @@ static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
 	return ktime_to_ns(timer->node.expires);
 }
 
-static inline ktime_t hrtimer_cb_get_time(const struct hrtimer *timer)
-{
-	return timer->base->get_time();
-}
+ktime_t hrtimer_cb_get_time(const struct hrtimer *timer);
 
 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
 {

include/linux/hrtimer_defs.h

@@ -41,7 +41,6 @@
  * @seq:		seqcount around __run_hrtimer
  * @running:		pointer to the currently running hrtimer
  * @active:		red black tree root node for the active timers
- * @get_time:		function to retrieve the current time of the clock
  * @offset:		offset of this clock to the monotonic base
  */
 struct hrtimer_clock_base {
@@ -51,7 +50,6 @@ struct hrtimer_clock_base {
 	seqcount_raw_spinlock_t	seq;
 	struct hrtimer		*running;
 	struct timerqueue_head	active;
-	ktime_t			(*get_time)(void);
 	ktime_t			offset;
 } __hrtimer_clock_base_align;
 

kernel/time/hrtimer.c

@@ -59,6 +59,7 @@
 #define HRTIMER_ACTIVE_ALL	(HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
 
 static void retrigger_next_event(void *arg);
+static ktime_t __hrtimer_cb_get_time(clockid_t clock_id);
 
 /*
  * The timer bases:
@@ -76,42 +77,34 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
 		{
 			.index = HRTIMER_BASE_MONOTONIC,
 			.clockid = CLOCK_MONOTONIC,
-			.get_time = &ktime_get,
 		},
 		{
 			.index = HRTIMER_BASE_REALTIME,
 			.clockid = CLOCK_REALTIME,
-			.get_time = &ktime_get_real,
 		},
 		{
 			.index = HRTIMER_BASE_BOOTTIME,
 			.clockid = CLOCK_BOOTTIME,
-			.get_time = &ktime_get_boottime,
 		},
 		{
 			.index = HRTIMER_BASE_TAI,
 			.clockid = CLOCK_TAI,
-			.get_time = &ktime_get_clocktai,
 		},
 		{
 			.index = HRTIMER_BASE_MONOTONIC_SOFT,
 			.clockid = CLOCK_MONOTONIC,
-			.get_time = &ktime_get,
 		},
 		{
 			.index = HRTIMER_BASE_REALTIME_SOFT,
 			.clockid = CLOCK_REALTIME,
-			.get_time = &ktime_get_real,
 		},
 		{
 			.index = HRTIMER_BASE_BOOTTIME_SOFT,
 			.clockid = CLOCK_BOOTTIME,
-			.get_time = &ktime_get_boottime,
 		},
 		{
 			.index = HRTIMER_BASE_TAI_SOFT,
 			.clockid = CLOCK_TAI,
-			.get_time = &ktime_get_clocktai,
 		},
 	},
 	.csd = CSD_INIT(retrigger_next_event, NULL)
@@ -1253,7 +1246,7 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
 	remove_hrtimer(timer, base, true, force_local);
 
 	if (mode & HRTIMER_MODE_REL)
-		tim = ktime_add_safe(tim, base->get_time());
+		tim = ktime_add_safe(tim, __hrtimer_cb_get_time(base->clockid));
 
 	tim = hrtimer_update_lowres(timer, tim, mode);
 
@@ -1588,6 +1581,29 @@ static inline int hrtimer_clockid_to_base(clockid_t clock_id)
 	}
 }
 
+static ktime_t __hrtimer_cb_get_time(clockid_t clock_id)
+{
+	switch (clock_id) {
+	case CLOCK_MONOTONIC:
+		return ktime_get();
+	case CLOCK_REALTIME:
+		return ktime_get_real();
+	case CLOCK_BOOTTIME:
+		return ktime_get_boottime();
+	case CLOCK_TAI:
+		return ktime_get_clocktai();
+	default:
+		WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
+		return ktime_get();
+	}
+}
+
+ktime_t hrtimer_cb_get_time(const struct hrtimer *timer)
+{
+	return __hrtimer_cb_get_time(timer->base->clockid);
+}
+EXPORT_SYMBOL_GPL(hrtimer_cb_get_time);
+
 static void __hrtimer_setup(struct hrtimer *timer,
 			    enum hrtimer_restart (*function)(struct hrtimer *),
 			    clockid_t clock_id, enum hrtimer_mode mode)

kernel/time/timer_list.c

@@ -102,8 +102,6 @@ print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 	SEQ_printf(m, "  .index:      %d\n", base->index);
 
 	SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
-
-	SEQ_printf(m,   "  .get_time:   %ps\n", base->get_time);
 #ifdef CONFIG_HIGH_RES_TIMERS
 	SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 		   (unsigned long long) ktime_to_ns(base->offset));

scripts/gdb/linux/timerlist.py

@@ -56,8 +56,6 @@ def print_base(base):
     text += " .index:      {}\n".format(base['index'])
 
     text += " .resolution: {} nsecs\n".format(constants.LX_hrtimer_resolution)
-
-    text += " .get_time:   {}\n".format(base['get_time'])
     if constants.LX_CONFIG_HIGH_RES_TIMERS:
         text += "  .offset:     {} nsecs\n".format(base['offset'])
     text += "active timers:\n"