diff --git a/drivers/timer/cavs_timer.c b/drivers/timer/cavs_timer.c
index cd7b217ce5b..46c80271d38 100644
--- a/drivers/timer/cavs_timer.c
+++ b/drivers/timer/cavs_timer.c
@@ -88,7 +88,7 @@ static void compare_isr(const void *arg)
 	curr = count();
 
 #ifdef CONFIG_SMP
-	/* If it has been too long since last_count,
+	/* If we are too soon since last_count,
 	 * this interrupt is likely the same interrupt
 	 * event but being processed by another CPU.
 	 * Since it has already been processed and
@@ -121,6 +121,7 @@ static void compare_isr(const void *arg)
 	sys_clock_announce(dticks);
 }
 
+/* Runs on core 0 only */
 int sys_clock_driver_init(const struct device *dev)
 {
 	uint64_t curr = count();
@@ -181,7 +182,8 @@ uint32_t sys_clock_cycle_get_32(void)
 	return count32();
 }
 
-#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 1
+#if defined(CONFIG_SMP) && CONFIG_MP_NUM_CPUS > 1 && !defined(CONFIG_SMP_BOOT_DELAY)
+/* Runs on secondary cores */
 void smp_timer_init(void)
 {
 	/* This enables the Timer 0 (or 1) interrupt for CPU n.
diff --git a/kernel/include/kernel_internal.h b/kernel/include/kernel_internal.h
index e55c73fa6f0..684d87dc07c 100644
--- a/kernel/include/kernel_internal.h
+++ b/kernel/include/kernel_internal.h
@@ -136,9 +136,13 @@ z_thread_return_value_set_with_data(struct k_thread *thread,
 	thread->base.swap_data = data;
 }
 
+#ifdef CONFIG_SMP
 extern void z_smp_init(void);
 
+#if CONFIG_MP_NUM_CPUS > 1 && !defined(CONFIG_SMP_BOOT_DELAY)
 extern void smp_timer_init(void);
+#endif
+#endif
 
 extern void z_early_boot_rand_get(uint8_t *buf, size_t length);