diff --git a/include/vdso/math64.h b/include/vdso/math64.h
index 3c08909e742b..6f1e311cfdbd 100644
--- a/include/vdso/math64.h
+++ b/include/vdso/math64.h
@@ -24,6 +24,26 @@ static __always_inline u32 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *re
 	return ret;
 }
 
+static __always_inline u32 __iter_div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
+{
+	u32 ret = 0;
+
+	while (dividend >= divisor) {
+		/*
+		 * Prevent the compiler from optimising this loop into a
+		 * modulo operation.
+		 */
+		OPTIMIZER_HIDE_VAR(dividend);
+
+		dividend -= divisor;
+		ret++;
+	}
+
+	*remainder = dividend;
+
+	return ret;
+}
+
 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
 
 #ifndef mul_u64_u32_add_u64_shr
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index b314d6d4dce7..bd57c54a07c3 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -54,14 +54,12 @@ static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct ti
 
 	nsec = tk->tkr_mono.xtime_nsec;
 	nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
-	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
-		nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
-		vdso_ts->sec++;
-	}
-	vdso_ts->nsec	= nsec;
+	vdso_ts->sec	+= __iter_div64_u64_rem(nsec, (u64)NSEC_PER_SEC << tk->tkr_mono.shift,
+						&vdso_ts->nsec);
 
 	/* Copy MONOTONIC time for BOOTTIME */
 	sec	= vdso_ts->sec;
+	nsec	= vdso_ts->nsec;
 	/* Add the boot offset */
 	sec	+= tk->monotonic_to_boot.tv_sec;
 	nsec	+= (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift;
@@ -69,12 +67,8 @@ static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct ti
 	/* CLOCK_BOOTTIME */
 	vdso_ts		= &vc[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
 	vdso_ts->sec	= sec;
-
-	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
-		nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
-		vdso_ts->sec++;
-	}
-	vdso_ts->nsec	= nsec;
+	vdso_ts->sec	+= __iter_div64_u64_rem(nsec, (u64)NSEC_PER_SEC << tk->tkr_mono.shift,
+						&vdso_ts->nsec);
 
 	/* CLOCK_MONOTONIC_RAW */
 	vdso_ts		= &vc[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];