diff --git a/sys/arm64/arm64/intr_machdep.c b/sys/arm64/arm64/intr_machdep.c
index 3389c69da942..70902ce2e776 100644
--- a/sys/arm64/arm64/intr_machdep.c
+++ b/sys/arm64/arm64/intr_machdep.c
@@ -105,7 +105,7 @@ static void
 intr_init(void *dummy __unused)
 {
 
-	mtx_init(&intr_list_lock, "intr sources lock", NULL, MTX_DEF);
+	mtx_init(&intr_list_lock, "intr sources lock", NULL, MTX_SPIN);
 }
 SYSINIT(intr_init, SI_SUB_INTR, SI_ORDER_FIRST, intr_init, NULL);
 
@@ -123,33 +123,44 @@ intrcnt_setname(const char *name, u_int idx)
 }
 
 /*
- * Get intr structure for the given interrupt number.
- * Allocate one if this is the first time.
- * (Similar to ppc's intr_lookup() but without actual
- * lookup since irq number is an index in arm64_intrs[]).
+ * Find the interrupt descriptor in the list
+ * based on the hardware IRQ number.
  */
-static struct arm64_intr_entry *
-intr_acquire(u_int hw_irq)
+static __inline struct arm64_intr_entry *
+intr_lookup_locked(u_int hw_irq)
 {
 	struct arm64_intr_entry *intr;
 
-	mtx_lock(&intr_list_lock);
-
+	mtx_assert(&intr_list_lock, MA_OWNED);
 	SLIST_FOREACH(intr, &irq_slist_head, entries) {
-		if (intr->i_hw_irq == hw_irq) {
-			break;
-		}
+		if (intr->i_hw_irq == hw_irq)
+			return (intr);
 	}
+	return (NULL);
+}
+/*
+ * Get intr structure for the given interrupt number.
+ * Allocate one if this is the first time.
+ */
+static struct arm64_intr_entry *
+intr_allocate(u_int hw_irq)
+{
+	struct arm64_intr_entry *intr;
+
+	/* Check if already allocated */
+	mtx_lock_spin(&intr_list_lock);
+	intr = intr_lookup_locked(hw_irq);
+	mtx_unlock_spin(&intr_list_lock);
 	if (intr != NULL)
-		goto out;
+		return (intr);
 
 	/* Do not alloc another intr when max number of IRQs has been reached */
 	if (intrcntidx >= NIRQS)
-		goto out;
+		return (NULL);
 
 	intr = malloc(sizeof(*intr), M_INTR, M_NOWAIT);
 	if (intr == NULL)
-		goto out;
+		return (NULL);
 
 	intr->i_event = NULL;
 	intr->i_handlers = 0;
@@ -158,9 +169,10 @@ intr_acquire(u_int hw_irq)
 	intr->i_cntidx = atomic_fetchadd_int(&intrcntidx, 1);
 	intr->i_cntp = &intrcnt[intr->i_cntidx];
 	intr->i_hw_irq = hw_irq;
+	mtx_lock_spin(&intr_list_lock);
 	SLIST_INSERT_HEAD(&irq_slist_head, intr, entries);
-out:
-	mtx_unlock(&intr_list_lock);
+	mtx_unlock_spin(&intr_list_lock);
+
 	return intr;
 }
 
@@ -312,7 +324,7 @@ arm_setup_intr(const char *name, driver_filter_t *filt, driver_intr_t handler,
 	struct arm64_intr_entry *intr;
 	int error;
 
-	intr = intr_acquire(hw_irq);
+	intr = intr_allocate(hw_irq);
 	if (intr == NULL)
 		return (ENOMEM);
 
@@ -336,7 +348,6 @@ arm_setup_intr(const char *name, driver_filter_t *filt, driver_intr_t handler,
 	    intr_priority(flags), flags, cookiep);
 
 	if (!error) {
-		mtx_lock(&intr_list_lock);
 		intrcnt_setname(intr->i_event->ie_fullname, intr->i_cntidx);
 		intr->i_handlers++;
 
@@ -349,7 +360,6 @@ arm_setup_intr(const char *name, driver_filter_t *filt, driver_intr_t handler,
 
 			PIC_UNMASK(root_pic, intr->i_hw_irq);
 		}
-		mtx_unlock(&intr_list_lock);
 	}
 
 	return (error);
@@ -364,12 +374,10 @@ arm_teardown_intr(void *cookie)
 	intr = intr_handler_source(cookie);
 	error = intr_event_remove_handler(cookie);
 	if (!error) {
-		mtx_lock(&intr_list_lock);
 		intr->i_handlers--;
 		if (intr->i_handlers == 0)
 			PIC_MASK(root_pic, intr->i_hw_irq);
 		intrcnt_setname(intr->i_event->ie_fullname, intr->i_cntidx);
-		mtx_unlock(&intr_list_lock);
 	}
 
 	return (error);
@@ -380,9 +388,11 @@ arm_config_intr(u_int hw_irq, enum intr_trigger trig, enum intr_polarity pol)
 {
 	struct arm64_intr_entry *intr;
 
-	intr = intr_acquire(hw_irq);
+	mtx_lock_spin(&intr_list_lock);
+	intr = intr_lookup_locked(hw_irq);
+	mtx_unlock_spin(&intr_list_lock);
 	if (intr == NULL)
-		return (ENOMEM);
+		return (EINVAL);
 
 	intr->i_trig = trig;
 	intr->i_pol = pol;
@@ -398,12 +408,9 @@ arm_dispatch_intr(u_int hw_irq, struct trapframe *tf)
 {
 	struct arm64_intr_entry *intr;
 
-	SLIST_FOREACH(intr, &irq_slist_head, entries) {
-		if (intr->i_hw_irq == hw_irq) {
-			break;
-		}
-	}
-
+	mtx_lock_spin(&intr_list_lock);
+	intr = intr_lookup_locked(hw_irq);
+	mtx_unlock_spin(&intr_list_lock);
 	if (intr == NULL)
 		goto stray;