diff --git a/sys/amd64/amd64/intr_machdep.c b/sys/amd64/amd64/intr_machdep.c
new file mode 100644
index 000000000000..2a4ece4d93e0
--- /dev/null
+++ b/sys/amd64/amd64/intr_machdep.c
@@ -0,0 +1,296 @@
+/*-
+ * Copyright (c) 2003 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Machine dependent interrupt code for i386.  For the i386, we have to
+ * deal with different PICs.  Thus, we use the passed in vector to lookup
+ * an interrupt source associated with that vector.  The interrupt source
+ * describes which PIC the source belongs to and includes methods to handle
+ * that source.
+ */
+
+#include "opt_ddb.h"
+
+#include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/interrupt.h>
+#include <sys/lock.h>
+#include <sys/ktr.h>
+#include <sys/kernel.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
+#include <sys/syslog.h>
+#include <sys/systm.h>
+#include <machine/intr_machdep.h>
+#ifdef DDB
+#include <ddb/ddb.h>
+#endif
+
+#define	MAX_STRAY_LOG	5
+
+typedef void (*mask_fn)(int vector);
+
+static int intrcnt_index;
+static struct intsrc *interrupt_sources[NUM_IO_INTS];
+static struct mtx intr_table_lock;
+
+static void	intr_init(void *__dummy);
+static void	intrcnt_setname(const char *name, int index);
+static void	intrcnt_updatename(struct intsrc *is);
+static void	intrcnt_register(struct intsrc *is);
+
+/*
+ * Register a new interrupt source with the global interrupt system.
+ * The global interrupts need to be disabled when this function is
+ * called.
+ */
+int
+intr_register_source(struct intsrc *isrc)
+{
+	int error, vector;
+
+	vector = isrc->is_pic->pic_vector(isrc);
+	if (interrupt_sources[vector] != NULL)
+		return (EEXIST);
+	/*
+	 * Ok, so this is kind of a nasty optimization that only works
+	 * because sizeof(int) == sizeof(void *) on i386.  If we passed
+	 * in the actual vector to ithread_create and then used wrapper
+	 * functions for disable_intsrc and enable_intsrc, then we'd
+	 * have to go lookup in the table everytime we enabled/disabled
+	 * the interrupt source.  That involves looking at a lock, etc.
+	 * and is just ugly.  Instead, we cast the pointer to the intsrc
+	 * to an int (yuck) and pass in the actual PIC methods meaning
+	 * that when we enable/disable an interrupt we call the PIC
+	 * methods directly.
+	 */
+	error = ithread_create(&isrc->is_ithread, (intptr_t)isrc, 0,
+	    (mask_fn)isrc->is_pic->pic_disable_source,
+	    (mask_fn)isrc->is_pic->pic_enable_source, "irq%d:", vector);
+	if (error)
+		return (error);
+	mtx_lock_spin(&intr_table_lock);
+	if (interrupt_sources[vector] != NULL) {
+		mtx_unlock_spin(&intr_table_lock);
+		ithread_destroy(isrc->is_ithread);
+		return (EEXIST);
+	}
+	intrcnt_register(isrc);
+	interrupt_sources[vector] = isrc;
+	mtx_unlock_spin(&intr_table_lock);
+	return (0);
+}
+
+struct intsrc *
+intr_lookup_source(int vector)
+{
+
+	return (interrupt_sources[vector]);
+}
+
+int
+intr_add_handler(const char *name, int vector, driver_intr_t handler,
+    void *arg, enum intr_type flags, void **cookiep)
+{
+	struct intsrc *isrc;
+	int error;
+
+	isrc = intr_lookup_source(vector);
+	if (isrc == NULL)
+		return (EINVAL);
+	error = ithread_add_handler(isrc->is_ithread, name, handler, arg,
+	    ithread_priority(flags), flags, cookiep);
+	if (error == 0) {
+		intrcnt_updatename(isrc);
+		isrc->is_pic->pic_enable_intr(isrc);
+		isrc->is_pic->pic_enable_source(isrc);
+	}
+	return (error);
+}
+
+int
+intr_remove_handler(void *cookie)
+{
+	int error;
+
+	error = ithread_remove_handler(cookie);
+#ifdef XXX
+	if (error == 0)
+		intrcnt_updatename(/* XXX */);
+#endif
+	return (error);
+}
+
+void
+intr_execute_handlers(struct intsrc *isrc, struct intrframe *iframe)
+{
+	struct ithd *it;
+	struct intrhand *ih;
+	int error, vector;
+
+	/*
+	 * We count software interrupts when we process them.  The
+	 * code here follows previous practice, but there's an
+	 * argument for counting hardware interrupts when they're
+	 * processed too.
+	 */
+	atomic_add_long(isrc->is_count, 1);
+	atomic_add_int(&cnt.v_intr, 1);
+
+	/*
+	 * Execute fast interrupt handlers directly.
+	 * To support clock handlers, if a handler registers
+	 * with a NULL argument, then we pass it a pointer to
+	 * a trapframe as its argument.
+	 */
+	it = isrc->is_ithread;
+	ih = TAILQ_FIRST(&it->it_handlers);
+	critical_enter();
+	if (ih == NULL)
+		error = EINVAL;
+	else if (ih->ih_flags & IH_FAST) {
+		TAILQ_FOREACH(ih, &it->it_handlers, ih_next) {
+			MPASS(ih->ih_flags & IH_FAST);
+			CTR3(KTR_INTR, "%s: executing handler %p(%p)",
+			    __func__, ih->ih_handler,
+			    ih->ih_argument == NULL ? iframe :
+			    ih->ih_argument);
+			if (ih->ih_argument == NULL)
+				ih->ih_handler(iframe);
+			else
+				ih->ih_handler(ih->ih_argument);
+		}
+		isrc->is_pic->pic_enable_source(isrc);
+		error = 0;
+	} else
+		error = ithread_schedule(it, !cold);
+	critical_exit();
+	if (error == EINVAL) {
+		vector = isrc->is_pic->pic_vector(isrc);
+		atomic_add_long(isrc->is_straycount, 1);
+		if (*isrc->is_straycount < MAX_STRAY_LOG)
+			log(LOG_ERR, "stray irq%d\n", vector);
+		else if (*isrc->is_straycount == MAX_STRAY_LOG)
+			log(LOG_CRIT,
+			    "too many stray irq %d's: not logging anymore\n",
+			    vector);
+	}
+}
+
+void
+intr_resume(void)
+{
+	struct intsrc **isrc;
+	int i;
+
+	mtx_lock_spin(&intr_table_lock);
+	for (i = 0, isrc = interrupt_sources; i < NUM_IO_INTS; i++, isrc++)
+		if (*isrc != NULL && (*isrc)->is_pic->pic_resume != NULL)
+			(*isrc)->is_pic->pic_resume(*isrc);
+	mtx_unlock_spin(&intr_table_lock);
+}
+
+void
+intr_suspend(void)
+{
+	struct intsrc **isrc;
+	int i;
+
+	mtx_lock_spin(&intr_table_lock);
+	for (i = 0, isrc = interrupt_sources; i < NUM_IO_INTS; i++, isrc++)
+		if (*isrc != NULL && (*isrc)->is_pic->pic_suspend != NULL)
+			(*isrc)->is_pic->pic_suspend(*isrc);
+	mtx_unlock_spin(&intr_table_lock);
+}
+
+static void
+intrcnt_setname(const char *name, int index)
+{
+
+	snprintf(intrnames + (MAXCOMLEN + 1) * index, MAXCOMLEN + 1, "%-*s",
+	    MAXCOMLEN, name);
+}
+
+static void
+intrcnt_updatename(struct intsrc *is)
+{
+
+	intrcnt_setname(is->is_ithread->it_td->td_proc->p_comm, is->is_index);
+}
+
+static void
+intrcnt_register(struct intsrc *is)
+{
+	char straystr[MAXCOMLEN + 1];
+
+	/* mtx_assert(&intr_table_lock, MA_OWNED); */
+	KASSERT(is->is_ithread != NULL, ("%s: isrc with no ithread", __func__));
+	is->is_index = intrcnt_index;
+	intrcnt_index += 2;
+	snprintf(straystr, MAXCOMLEN + 1, "stray irq%d",
+	    is->is_pic->pic_vector(is));
+	intrcnt_updatename(is);
+	is->is_count = &intrcnt[is->is_index];
+	intrcnt_setname(straystr, is->is_index + 1);
+	is->is_straycount = &intrcnt[is->is_index + 1];
+}
+
+static void
+intr_init(void *dummy __unused)
+{
+
+	intrcnt_setname("???", 0);
+	intrcnt_index = 1;
+	mtx_init(&intr_table_lock, "intr table", NULL, MTX_SPIN);
+}
+SYSINIT(intr_init, SI_SUB_INTR, SI_ORDER_FIRST, intr_init, NULL)
+
+#ifdef DDB
+/*
+ * Dump data about interrupt handlers
+ */
+DB_SHOW_COMMAND(irqs, db_show_irqs)
+{
+	struct intsrc **isrc;
+	int i, quit, verbose;
+
+	quit = 0;
+	if (strcmp(modif, "v") == 0)
+		verbose = 1;
+	else
+		verbose = 0;
+	isrc = interrupt_sources;
+	db_setup_paging(db_simple_pager, &quit, DB_LINES_PER_PAGE);
+	for (i = 0; i < NUM_IO_INTS && !quit; i++, isrc++)
+		if (*isrc != NULL)
+			db_dump_ithread((*isrc)->is_ithread, verbose);
+}
+#endif
diff --git a/sys/amd64/include/intr_machdep.h b/sys/amd64/include/intr_machdep.h
new file mode 100644
index 000000000000..ed89186f2cbe
--- /dev/null
+++ b/sys/amd64/include/intr_machdep.h
@@ -0,0 +1,91 @@
+/*-
+ * Copyright (c) 2003 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __MACHINE_INTR_MACHDEP_H__
+#define	__MACHINE_INTR_MACHDEP_H__
+
+#ifdef _KERNEL
+
+/* With I/O APIC's we can have up to 159 interrupts. */
+#define	NUM_IO_INTS	159
+#define	INTRCNT_COUNT	(1 + NUM_IO_INTS * 2)
+
+#ifndef LOCORE
+
+typedef void inthand_t(u_int cs, u_int ef, u_int esp, u_int ss);
+
+#define	IDTVEC(name)	__CONCAT(X,name)
+
+struct intsrc;
+
+/*
+ * Methods that a PIC provides to mask/unmask a given interrupt source,
+ * "turn on" the interrupt on the CPU side by setting up an IDT entry, and
+ * return the vector associated with this source.
+ */
+struct pic {
+	void (*pic_enable_source)(struct intsrc *);
+	void (*pic_disable_source)(struct intsrc *);
+	void (*pic_eoi_source)(struct intsrc *);
+	void (*pic_enable_intr)(struct intsrc *);
+	int (*pic_vector)(struct intsrc *);
+	int (*pic_source_pending)(struct intsrc *);
+	void (*pic_suspend)(struct intsrc *);
+	void (*pic_resume)(struct intsrc *);
+};
+
+/*
+ * An interrupt source.  The upper-layer code uses the PIC methods to
+ * control a given source.  The lower-layer PIC drivers can store additional
+ * private data in a given interrupt source such as an interrupt pin number
+ * or an I/O APIC pointer.
+ */
+struct intsrc {
+	struct pic *is_pic;
+	struct ithd *is_ithread;
+	u_long *is_count;
+	u_long *is_straycount;
+	u_int is_index;
+};
+
+struct intrframe;
+
+extern struct mtx icu_lock;
+
+int	intr_add_handler(const char *name, int vector, driver_intr_t handler,
+    void *arg, enum intr_type flags, void **cookiep);
+void	intr_execute_handlers(struct intsrc *isrc, struct intrframe *iframe);
+struct intsrc *intr_lookup_source(int vector);
+int	intr_register_source(struct intsrc *isrc);
+int	intr_remove_handler(void *cookie);
+void	intr_resume(void);
+void	intr_suspend(void);
+
+#endif	/* !LOCORE */
+#endif	/* _KERNEL */
+#endif	/* !__MACHINE_INTR_MACHDEP_H__ */
diff --git a/sys/i386/i386/intr_machdep.c b/sys/i386/i386/intr_machdep.c
new file mode 100644
index 000000000000..2a4ece4d93e0
--- /dev/null
+++ b/sys/i386/i386/intr_machdep.c
@@ -0,0 +1,296 @@
+/*-
+ * Copyright (c) 2003 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Machine dependent interrupt code for i386.  For the i386, we have to
+ * deal with different PICs.  Thus, we use the passed in vector to lookup
+ * an interrupt source associated with that vector.  The interrupt source
+ * describes which PIC the source belongs to and includes methods to handle
+ * that source.
+ */
+
+#include "opt_ddb.h"
+
+#include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/interrupt.h>
+#include <sys/lock.h>
+#include <sys/ktr.h>
+#include <sys/kernel.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
+#include <sys/syslog.h>
+#include <sys/systm.h>
+#include <machine/intr_machdep.h>
+#ifdef DDB
+#include <ddb/ddb.h>
+#endif
+
+#define	MAX_STRAY_LOG	5
+
+typedef void (*mask_fn)(int vector);
+
+static int intrcnt_index;
+static struct intsrc *interrupt_sources[NUM_IO_INTS];
+static struct mtx intr_table_lock;
+
+static void	intr_init(void *__dummy);
+static void	intrcnt_setname(const char *name, int index);
+static void	intrcnt_updatename(struct intsrc *is);
+static void	intrcnt_register(struct intsrc *is);
+
+/*
+ * Register a new interrupt source with the global interrupt system.
+ * The global interrupts need to be disabled when this function is
+ * called.
+ */
+int
+intr_register_source(struct intsrc *isrc)
+{
+	int error, vector;
+
+	vector = isrc->is_pic->pic_vector(isrc);
+	if (interrupt_sources[vector] != NULL)
+		return (EEXIST);
+	/*
+	 * Ok, so this is kind of a nasty optimization that only works
+	 * because sizeof(int) == sizeof(void *) on i386.  If we passed
+	 * in the actual vector to ithread_create and then used wrapper
+	 * functions for disable_intsrc and enable_intsrc, then we'd
+	 * have to go lookup in the table everytime we enabled/disabled
+	 * the interrupt source.  That involves looking at a lock, etc.
+	 * and is just ugly.  Instead, we cast the pointer to the intsrc
+	 * to an int (yuck) and pass in the actual PIC methods meaning
+	 * that when we enable/disable an interrupt we call the PIC
+	 * methods directly.
+	 */
+	error = ithread_create(&isrc->is_ithread, (intptr_t)isrc, 0,
+	    (mask_fn)isrc->is_pic->pic_disable_source,
+	    (mask_fn)isrc->is_pic->pic_enable_source, "irq%d:", vector);
+	if (error)
+		return (error);
+	mtx_lock_spin(&intr_table_lock);
+	if (interrupt_sources[vector] != NULL) {
+		mtx_unlock_spin(&intr_table_lock);
+		ithread_destroy(isrc->is_ithread);
+		return (EEXIST);
+	}
+	intrcnt_register(isrc);
+	interrupt_sources[vector] = isrc;
+	mtx_unlock_spin(&intr_table_lock);
+	return (0);
+}
+
+struct intsrc *
+intr_lookup_source(int vector)
+{
+
+	return (interrupt_sources[vector]);
+}
+
+int
+intr_add_handler(const char *name, int vector, driver_intr_t handler,
+    void *arg, enum intr_type flags, void **cookiep)
+{
+	struct intsrc *isrc;
+	int error;
+
+	isrc = intr_lookup_source(vector);
+	if (isrc == NULL)
+		return (EINVAL);
+	error = ithread_add_handler(isrc->is_ithread, name, handler, arg,
+	    ithread_priority(flags), flags, cookiep);
+	if (error == 0) {
+		intrcnt_updatename(isrc);
+		isrc->is_pic->pic_enable_intr(isrc);
+		isrc->is_pic->pic_enable_source(isrc);
+	}
+	return (error);
+}
+
+int
+intr_remove_handler(void *cookie)
+{
+	int error;
+
+	error = ithread_remove_handler(cookie);
+#ifdef XXX
+	if (error == 0)
+		intrcnt_updatename(/* XXX */);
+#endif
+	return (error);
+}
+
+void
+intr_execute_handlers(struct intsrc *isrc, struct intrframe *iframe)
+{
+	struct ithd *it;
+	struct intrhand *ih;
+	int error, vector;
+
+	/*
+	 * We count software interrupts when we process them.  The
+	 * code here follows previous practice, but there's an
+	 * argument for counting hardware interrupts when they're
+	 * processed too.
+	 */
+	atomic_add_long(isrc->is_count, 1);
+	atomic_add_int(&cnt.v_intr, 1);
+
+	/*
+	 * Execute fast interrupt handlers directly.
+	 * To support clock handlers, if a handler registers
+	 * with a NULL argument, then we pass it a pointer to
+	 * a trapframe as its argument.
+	 */
+	it = isrc->is_ithread;
+	ih = TAILQ_FIRST(&it->it_handlers);
+	critical_enter();
+	if (ih == NULL)
+		error = EINVAL;
+	else if (ih->ih_flags & IH_FAST) {
+		TAILQ_FOREACH(ih, &it->it_handlers, ih_next) {
+			MPASS(ih->ih_flags & IH_FAST);
+			CTR3(KTR_INTR, "%s: executing handler %p(%p)",
+			    __func__, ih->ih_handler,
+			    ih->ih_argument == NULL ? iframe :
+			    ih->ih_argument);
+			if (ih->ih_argument == NULL)
+				ih->ih_handler(iframe);
+			else
+				ih->ih_handler(ih->ih_argument);
+		}
+		isrc->is_pic->pic_enable_source(isrc);
+		error = 0;
+	} else
+		error = ithread_schedule(it, !cold);
+	critical_exit();
+	if (error == EINVAL) {
+		vector = isrc->is_pic->pic_vector(isrc);
+		atomic_add_long(isrc->is_straycount, 1);
+		if (*isrc->is_straycount < MAX_STRAY_LOG)
+			log(LOG_ERR, "stray irq%d\n", vector);
+		else if (*isrc->is_straycount == MAX_STRAY_LOG)
+			log(LOG_CRIT,
+			    "too many stray irq %d's: not logging anymore\n",
+			    vector);
+	}
+}
+
+void
+intr_resume(void)
+{
+	struct intsrc **isrc;
+	int i;
+
+	mtx_lock_spin(&intr_table_lock);
+	for (i = 0, isrc = interrupt_sources; i < NUM_IO_INTS; i++, isrc++)
+		if (*isrc != NULL && (*isrc)->is_pic->pic_resume != NULL)
+			(*isrc)->is_pic->pic_resume(*isrc);
+	mtx_unlock_spin(&intr_table_lock);
+}
+
+void
+intr_suspend(void)
+{
+	struct intsrc **isrc;
+	int i;
+
+	mtx_lock_spin(&intr_table_lock);
+	for (i = 0, isrc = interrupt_sources; i < NUM_IO_INTS; i++, isrc++)
+		if (*isrc != NULL && (*isrc)->is_pic->pic_suspend != NULL)
+			(*isrc)->is_pic->pic_suspend(*isrc);
+	mtx_unlock_spin(&intr_table_lock);
+}
+
+static void
+intrcnt_setname(const char *name, int index)
+{
+
+	snprintf(intrnames + (MAXCOMLEN + 1) * index, MAXCOMLEN + 1, "%-*s",
+	    MAXCOMLEN, name);
+}
+
+static void
+intrcnt_updatename(struct intsrc *is)
+{
+
+	intrcnt_setname(is->is_ithread->it_td->td_proc->p_comm, is->is_index);
+}
+
+static void
+intrcnt_register(struct intsrc *is)
+{
+	char straystr[MAXCOMLEN + 1];
+
+	/* mtx_assert(&intr_table_lock, MA_OWNED); */
+	KASSERT(is->is_ithread != NULL, ("%s: isrc with no ithread", __func__));
+	is->is_index = intrcnt_index;
+	intrcnt_index += 2;
+	snprintf(straystr, MAXCOMLEN + 1, "stray irq%d",
+	    is->is_pic->pic_vector(is));
+	intrcnt_updatename(is);
+	is->is_count = &intrcnt[is->is_index];
+	intrcnt_setname(straystr, is->is_index + 1);
+	is->is_straycount = &intrcnt[is->is_index + 1];
+}
+
+static void
+intr_init(void *dummy __unused)
+{
+
+	intrcnt_setname("???", 0);
+	intrcnt_index = 1;
+	mtx_init(&intr_table_lock, "intr table", NULL, MTX_SPIN);
+}
+SYSINIT(intr_init, SI_SUB_INTR, SI_ORDER_FIRST, intr_init, NULL)
+
+#ifdef DDB
+/*
+ * Dump data about interrupt handlers
+ */
+DB_SHOW_COMMAND(irqs, db_show_irqs)
+{
+	struct intsrc **isrc;
+	int i, quit, verbose;
+
+	quit = 0;
+	if (strcmp(modif, "v") == 0)
+		verbose = 1;
+	else
+		verbose = 0;
+	isrc = interrupt_sources;
+	db_setup_paging(db_simple_pager, &quit, DB_LINES_PER_PAGE);
+	for (i = 0; i < NUM_IO_INTS && !quit; i++, isrc++)
+		if (*isrc != NULL)
+			db_dump_ithread((*isrc)->is_ithread, verbose);
+}
+#endif
diff --git a/sys/i386/include/intr_machdep.h b/sys/i386/include/intr_machdep.h
new file mode 100644
index 000000000000..ed89186f2cbe
--- /dev/null
+++ b/sys/i386/include/intr_machdep.h
@@ -0,0 +1,91 @@
+/*-
+ * Copyright (c) 2003 John Baldwin <jhb@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __MACHINE_INTR_MACHDEP_H__
+#define	__MACHINE_INTR_MACHDEP_H__
+
+#ifdef _KERNEL
+
+/* With I/O APIC's we can have up to 159 interrupts. */
+#define	NUM_IO_INTS	159
+#define	INTRCNT_COUNT	(1 + NUM_IO_INTS * 2)
+
+#ifndef LOCORE
+
+typedef void inthand_t(u_int cs, u_int ef, u_int esp, u_int ss);
+
+#define	IDTVEC(name)	__CONCAT(X,name)
+
+struct intsrc;
+
+/*
+ * Methods that a PIC provides to mask/unmask a given interrupt source,
+ * "turn on" the interrupt on the CPU side by setting up an IDT entry, and
+ * return the vector associated with this source.
+ */
+struct pic {
+	void (*pic_enable_source)(struct intsrc *);
+	void (*pic_disable_source)(struct intsrc *);
+	void (*pic_eoi_source)(struct intsrc *);
+	void (*pic_enable_intr)(struct intsrc *);
+	int (*pic_vector)(struct intsrc *);
+	int (*pic_source_pending)(struct intsrc *);
+	void (*pic_suspend)(struct intsrc *);
+	void (*pic_resume)(struct intsrc *);
+};
+
+/*
+ * An interrupt source.  The upper-layer code uses the PIC methods to
+ * control a given source.  The lower-layer PIC drivers can store additional
+ * private data in a given interrupt source such as an interrupt pin number
+ * or an I/O APIC pointer.
+ */
+struct intsrc {
+	struct pic *is_pic;
+	struct ithd *is_ithread;
+	u_long *is_count;
+	u_long *is_straycount;
+	u_int is_index;
+};
+
+struct intrframe;
+
+extern struct mtx icu_lock;
+
+int	intr_add_handler(const char *name, int vector, driver_intr_t handler,
+    void *arg, enum intr_type flags, void **cookiep);
+void	intr_execute_handlers(struct intsrc *isrc, struct intrframe *iframe);
+struct intsrc *intr_lookup_source(int vector);
+int	intr_register_source(struct intsrc *isrc);
+int	intr_remove_handler(void *cookie);
+void	intr_resume(void);
+void	intr_suspend(void);
+
+#endif	/* !LOCORE */
+#endif	/* _KERNEL */
+#endif	/* !__MACHINE_INTR_MACHDEP_H__ */