diff --git a/sys/arm/arm/gic.c b/sys/arm/arm/gic.c
--- a/sys/arm/arm/gic.c
+++ b/sys/arm/arm/gic.c
@@ -200,7 +200,7 @@
 
 #ifdef SMP
 static void
-arm_gic_init_secondary(device_t dev, enum root_type root_type)
+arm_gic_init_secondary(device_t dev, enum intr_root_type root_type)
 {
 	struct arm_gic_softc *sc = device_get_softc(dev);
 	u_int irq, cpu;
diff --git a/sys/arm/broadcom/bcm2835/bcm2836.c b/sys/arm/broadcom/bcm2835/bcm2836.c
--- a/sys/arm/broadcom/bcm2835/bcm2836.c
+++ b/sys/arm/broadcom/bcm2835/bcm2836.c
@@ -538,7 +538,7 @@
 }
 
 static void
-bcm_lintc_init_secondary(device_t dev, enum root_type root_type)
+bcm_lintc_init_secondary(device_t dev, enum intr_root_type root_type)
 {
 	u_int cpu;
 	struct bcm_lintc_softc *sc;
diff --git a/sys/arm/include/intr.h b/sys/arm/include/intr.h
--- a/sys/arm/include/intr.h
+++ b/sys/arm/include/intr.h
@@ -43,10 +43,10 @@
 #include <dev/ofw/openfirm.h>
 #endif
 
-enum root_type {
-	INTR_ROOT_IRQ =	0,
+enum intr_root_type {
+	INTR_ROOT_IRQ,
 
-	INTR_ROOT_COUNT	/* MUST BE LAST */
+	INTR_ROOT_COUNT
 };
 
 #ifndef NIRQ
diff --git a/sys/arm64/arm64/exception.S b/sys/arm64/arm64/exception.S
--- a/sys/arm64/arm64/exception.S
+++ b/sys/arm64/arm64/exception.S
@@ -233,7 +233,7 @@
 	save_registers 1
 	KMSAN_ENTER
 	mov	x0, sp
-	mov	x1, #INTR_ROOT_IRQ
+	mov	w1, #INTR_ROOT_IRQ
 	bl	intr_irq_handler
 	KMSAN_LEAVE
 	restore_registers 1
@@ -244,7 +244,7 @@
 	save_registers 1
 	KMSAN_ENTER
 	mov	x0, sp
-	mov	x1, #INTR_ROOT_FIQ
+	mov	w1, #INTR_ROOT_FIQ
 	bl	intr_irq_handler
 	KMSAN_LEAVE
 	restore_registers 1
@@ -279,7 +279,7 @@
 	save_registers 0
 	KMSAN_ENTER
 	mov	x0, sp
-	mov	x1, #INTR_ROOT_IRQ
+	mov	w1, #INTR_ROOT_IRQ
 	bl	intr_irq_handler
 	do_ast
 	KMSAN_LEAVE
@@ -291,7 +291,7 @@
 	save_registers 0
 	KMSAN_ENTER
 	mov	x0, sp
-	mov	x1, #INTR_ROOT_FIQ
+	mov	w1, #INTR_ROOT_FIQ
 	bl	intr_irq_handler
 	do_ast
 	KMSAN_LEAVE
diff --git a/sys/arm64/arm64/gic_v3.c b/sys/arm64/arm64/gic_v3.c
--- a/sys/arm64/arm64/gic_v3.c
+++ b/sys/arm64/arm64/gic_v3.c
@@ -1093,7 +1093,7 @@
 
 #ifdef SMP
 static void
-gic_v3_init_secondary(device_t dev, enum root_type root_type)
+gic_v3_init_secondary(device_t dev, enum intr_root_type root_type)
 {
 	struct gic_v3_setup_periph_args pargs;
 	device_t child;
diff --git a/sys/arm64/arm64/gicv3_its.c b/sys/arm64/arm64/gicv3_its.c
--- a/sys/arm64/arm64/gicv3_its.c
+++ b/sys/arm64/arm64/gicv3_its.c
@@ -1293,7 +1293,7 @@
 
 #ifdef SMP
 static void
-gicv3_its_init_secondary(device_t dev, enum root_type root_type)
+gicv3_its_init_secondary(device_t dev, enum intr_root_type root_type)
 {
 	struct gicv3_its_softc *sc;
 
diff --git a/sys/arm64/include/intr.h b/sys/arm64/include/intr.h
--- a/sys/arm64/include/intr.h
+++ b/sys/arm64/include/intr.h
@@ -31,11 +31,11 @@
 #include <dev/ofw/openfirm.h>
 #endif
 
-enum root_type {
-	INTR_ROOT_IRQ =	0,
-	INTR_ROOT_FIQ =	1,
+enum intr_root_type {
+	INTR_ROOT_IRQ,
+	INTR_ROOT_FIQ,
 
-	INTR_ROOT_COUNT	/* MUST BE LAST */
+	INTR_ROOT_COUNT
 };
 
 #ifndef NIRQ
diff --git a/sys/kern/pic_if.m b/sys/kern/pic_if.m
--- a/sys/kern/pic_if.m
+++ b/sys/kern/pic_if.m
@@ -74,7 +74,7 @@
 	}
 
 	static void
-	null_pic_init_secondary(device_t dev, enum root_type root_type)
+	null_pic_init_secondary(device_t dev, enum intr_root_type root_type)
 	{
 	}
 
@@ -156,8 +156,8 @@
 };
 
 METHOD void init_secondary {
-	device_t	dev;
-	enum root_type	root_type;
+	device_t		dev;
+	enum intr_root_type	root_type;
 } DEFAULT null_pic_init_secondary;
 
 METHOD void ipi_send {
diff --git a/sys/kern/subr_intr.c b/sys/kern/subr_intr.c
--- a/sys/kern/subr_intr.c
+++ b/sys/kern/subr_intr.c
@@ -328,14 +328,14 @@
  *  from the assembler, where CPU interrupt is served.
  */
 void
-intr_irq_handler(struct trapframe *tf, u_register_t root_type)
+intr_irq_handler(struct trapframe *tf, enum intr_root_type root_type)
 {
 	struct trapframe * oldframe;
 	struct thread * td;
 	struct intr_irq_root *root;
 
-	KASSERT((uintmax_t)root_type < INTR_ROOT_COUNT,
-	    ("%s: invalid interrupt root %ju", __func__, (uintmax_t)root_type));
+	KASSERT(root_type >= 0 && root_type < INTR_ROOT_COUNT,
+	    ("%s: invalid interrupt root type %d", __func__, root_type));
 
 	root = &intr_irq_roots[root_type];
 	KASSERT(root->filter != NULL, ("%s: no filter", __func__));
@@ -486,10 +486,10 @@
 }
 
 device_t
-intr_irq_root_device(enum root_type root_type)
+intr_irq_root_device(enum intr_root_type root_type)
 {
-	KASSERT((uintmax_t)root_type < INTR_ROOT_COUNT,
-	    ("%s: invalid interrupt root %ju", __func__, (uintmax_t)root_type));
+	KASSERT(root_type >= 0 && root_type < INTR_ROOT_COUNT,
+	    ("%s: invalid interrupt root type %d", __func__, root_type));
 	return (intr_irq_roots[root_type].dev);
 }
 
@@ -891,7 +891,7 @@
  */
 int
 intr_pic_claim_root(device_t dev, intptr_t xref, intr_irq_filter_t *filter,
-    void *arg, enum root_type root_type)
+    void *arg, enum intr_root_type root_type)
 {
 	struct intr_pic *pic;
 	struct intr_irq_root *root;
@@ -916,8 +916,8 @@
 	 * Note that we further suppose that there is not threaded interrupt
 	 * routine (handler) on the root. See intr_irq_handler().
 	 */
-	KASSERT((uintmax_t)root_type < INTR_ROOT_COUNT,
-	    ("%s: invalid interrupt root %ju", __func__, (uintmax_t)root_type));
+	KASSERT(root_type >= 0 && root_type < INTR_ROOT_COUNT,
+	    ("%s: invalid interrupt root type %d", __func__, root_type));
 	root = &intr_irq_roots[root_type];
 	if (root->dev != NULL) {
 		device_printf(dev, "another root already set\n");
@@ -1571,7 +1571,7 @@
 intr_pic_init_secondary(void)
 {
 	device_t dev;
-	enum root_type root_type;
+	enum intr_root_type root_type;
 
 	/*
 	 * QQQ: Only root PICs are aware of other CPUs ???
diff --git a/sys/riscv/include/intr.h b/sys/riscv/include/intr.h
--- a/sys/riscv/include/intr.h
+++ b/sys/riscv/include/intr.h
@@ -35,10 +35,10 @@
 #ifndef	_MACHINE_INTR_MACHDEP_H_
 #define	_MACHINE_INTR_MACHDEP_H_
 
-enum root_type {
-	INTR_ROOT_IRQ = 0,
+enum intr_root_type {
+	INTR_ROOT_IRQ,
 
-	INTR_ROOT_COUNT	/* MUST BE LAST */
+	INTR_ROOT_COUNT
 };
 
 #ifndef	NIRQ
diff --git a/sys/riscv/riscv/intc.c b/sys/riscv/riscv/intc.c
--- a/sys/riscv/riscv/intc.c
+++ b/sys/riscv/riscv/intc.c
@@ -241,7 +241,7 @@
 
 #ifdef SMP
 static void
-intc_init_secondary(device_t dev, enum root_type root_type)
+intc_init_secondary(device_t dev, enum intr_root_type root_type)
 {
 	struct intc_softc *sc;
 	struct intr_irqsrc *isrc;
diff --git a/sys/sys/intr.h b/sys/sys/intr.h
--- a/sys/sys/intr.h
+++ b/sys/sys/intr.h
@@ -113,12 +113,12 @@
 struct intr_pic *intr_pic_register(device_t, intptr_t);
 int intr_pic_deregister(device_t, intptr_t);
 int intr_pic_claim_root(device_t, intptr_t, intr_irq_filter_t *, void *,
-    enum root_type);
+    enum intr_root_type);
 int intr_pic_add_handler(device_t, struct intr_pic *,
     intr_child_irq_filter_t *, void *, uintptr_t, uintptr_t);
 bool intr_is_per_cpu(struct resource *);
 
-device_t intr_irq_root_device(enum root_type);
+device_t intr_irq_root_device(enum intr_root_type);
 
 /* Intr interface for BUS. */
 
@@ -167,6 +167,6 @@
 #endif
 
 /* Main interrupt handler called from asm on many archs. */
-void intr_irq_handler(struct trapframe *tf, u_register_t root_type);
+void intr_irq_handler(struct trapframe *tf, enum intr_root_type root_type);
 
 #endif	/* _SYS_INTR_H */