Added methods to resolve linker errors.

3 files changed, 1868 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 3f1e7eef..27d2a223 100644
--- a/Makefile
+++ b/Makefile
@@ -368,6 +368,7 @@ C_FILES += freebsd/dev/pci/pci.c
 C_FILES += freebsd/kern/uipc_accf.c
 C_FILES += freebsd/kern/kern_ntptime.c
 C_FILES += freebsd/kern/kern_environment.c
+C_FILES += freebsd/kern/kern_intr.c
 C_FILES += freebsd/dev/re/if_re.c
 C_FILES += freebsd/dev/fxp/if_fxp.c
 C_FILES += freebsd/dev/e1000/e1000_80003es2lan.c
diff --git a/freebsd-to-rtems.py b/freebsd-to-rtems.py
index 1b679d31..d4406056 100755
--- a/freebsd-to-rtems.py
+++ b/freebsd-to-rtems.py
@@ -1208,6 +1208,7 @@ devNic.addSourceFiles(
 		'kern/uipc_accf.c',
 		'kern/kern_ntptime.c',
 		'kern/kern_environment.c',
+		'kern/kern_intr.c',
 	]
 )
 
diff --git a/freebsd/kern/kern_intr.c b/freebsd/kern/kern_intr.c
new file mode 100644
index 00000000..f93a72c6
--- /dev/null
+++ b/freebsd/kern/kern_intr.c
@@ -0,0 +1,1866 @@
+#include <freebsd/machine/rtems-bsd-config.h>
+
+/*-
+ * Copyright (c) 1997, Stefan Esser <se@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 unmodified, 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 ``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 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.
+ */
+
+#include <freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+
+#include <freebsd/local/opt_ddb.h>
+
+#include <freebsd/sys/param.h>
+#include <freebsd/sys/bus.h>
+#include <freebsd/sys/conf.h>
+#include <freebsd/sys/cpuset.h>
+#include <freebsd/sys/rtprio.h>
+#include <freebsd/sys/systm.h>
+#include <freebsd/sys/interrupt.h>
+#include <freebsd/sys/kernel.h>
+#include <freebsd/sys/kthread.h>
+#include <freebsd/sys/ktr.h>
+#include <freebsd/sys/limits.h>
+#include <freebsd/sys/lock.h>
+#include <freebsd/sys/malloc.h>
+#include <freebsd/sys/mutex.h>
+#include <freebsd/sys/priv.h>
+#include <freebsd/sys/proc.h>
+#include <freebsd/sys/random.h>
+#include <freebsd/sys/resourcevar.h>
+#include <freebsd/sys/sched.h>
+#include <freebsd/sys/smp.h>
+#include <freebsd/sys/sysctl.h>
+#include <freebsd/sys/syslog.h>
+#include <freebsd/sys/unistd.h>
+#ifndef __rtems__
+#include <freebsd/sys/vmmeter.h>
+#endif /* __rtems__ */
+#include <freebsd/machine/atomic.h>
+#include <freebsd/machine/cpu.h>
+#ifndef __rtems__
+#include <freebsd/machine/md_var.h>
+#include <freebsd/machine/stdarg.h>
+#ifdef DDB
+#include <freebsd/ddb/ddb.h>
+#include <freebsd/ddb/db_sym.h>
+#endif
+#endif /* __rtems__ */
+
+/*
+ * Describe an interrupt thread.  There is one of these per interrupt event.
+ */
+struct intr_thread {
+	struct intr_event *it_event;
+	struct thread *it_thread;	/* Kernel thread. */
+	int	it_flags;		/* (j) IT_* flags. */
+	int	it_need;		/* Needs service. */
+};
+
+/* Interrupt thread flags kept in it_flags */
+#define	IT_DEAD		0x000001	/* Thread is waiting to exit. */
+
+struct	intr_entropy {
+	struct	thread *td;
+	uintptr_t event;
+};
+
+struct	intr_event *clk_intr_event;
+struct	intr_event *tty_intr_event;
+void	*vm_ih;
+struct proc *intrproc;
+
+static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
+
+static int intr_storm_threshold = 1000;
+TUNABLE_INT("hw.intr_storm_threshold", &intr_storm_threshold);
+SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RW,
+    &intr_storm_threshold, 0,
+    "Number of consecutive interrupts before storm protection is enabled");
+static TAILQ_HEAD(, intr_event) event_list =
+    TAILQ_HEAD_INITIALIZER(event_list);
+static struct mtx event_lock;
+MTX_SYSINIT(intr_event_list, &event_lock, "intr event list", MTX_DEF);
+
+static void	intr_event_update(struct intr_event *ie);
+#ifndef __rtems__
+#ifdef INTR_FILTER
+static int	intr_event_schedule_thread(struct intr_event *ie,
+		    struct intr_thread *ithd);
+static int	intr_filter_loop(struct intr_event *ie,
+		    struct trapframe *frame, struct intr_thread **ithd);
+static struct intr_thread *ithread_create(const char *name,
+			      struct intr_handler *ih);
+#else
+static int	intr_event_schedule_thread(struct intr_event *ie);
+static struct intr_thread *ithread_create(const char *name);
+#endif
+static void	ithread_destroy(struct intr_thread *ithread);
+static void	ithread_execute_handlers(struct proc *p, 
+		    struct intr_event *ie);
+#ifdef INTR_FILTER
+static void	priv_ithread_execute_handler(struct proc *p, 
+		    struct intr_handler *ih);
+#endif
+static void	ithread_loop(void *);
+#endif /* __rtems__ */
+static void	ithread_update(struct intr_thread *ithd);
+#ifndef __rtems__
+static void	start_softintr(void *);
+
+/* Map an interrupt type to an ithread priority. */
+u_char
+intr_priority(enum intr_type flags)
+{
+	u_char pri;
+
+	flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET |
+	    INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV);
+	switch (flags) {
+	case INTR_TYPE_TTY:
+		pri = PI_TTYLOW;
+		break;
+	case INTR_TYPE_BIO:
+		/*
+		 * XXX We need to refine this.  BSD/OS distinguishes
+		 * between tape and disk priorities.
+		 */
+		pri = PI_DISK;
+		break;
+	case INTR_TYPE_NET:
+		pri = PI_NET;
+		break;
+	case INTR_TYPE_CAM:
+		pri = PI_DISK;          /* XXX or PI_CAM? */
+		break;
+	case INTR_TYPE_AV:		/* Audio/video */
+		pri = PI_AV;
+		break;
+	case INTR_TYPE_CLK:
+		pri = PI_REALTIME;
+		break;
+	case INTR_TYPE_MISC:
+		pri = PI_DULL;          /* don't care */
+		break;
+	default:
+		/* We didn't specify an interrupt level. */
+		panic("intr_priority: no interrupt type in flags");
+	}
+
+	return pri;
+}
+
+/*
+ * Update an ithread based on the associated intr_event.
+ */
+static void
+ithread_update(struct intr_thread *ithd)
+{
+	struct intr_event *ie;
+	struct thread *td;
+	u_char pri;
+
+	ie = ithd->it_event;
+	td = ithd->it_thread;
+
+	/* Determine the overall priority of this event. */
+	if (TAILQ_EMPTY(&ie->ie_handlers))
+		pri = PRI_MAX_ITHD;
+	else
+		pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri;
+
+	/* Update name and priority. */
+	strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
+	thread_lock(td);
+	sched_prio(td, pri);
+	thread_unlock(td);
+}
+#endif /* __rtems__ */
+
+/*
+ * Regenerate the full name of an interrupt event and update its priority.
+ */
+static void
+intr_event_update(struct intr_event *ie)
+{
+	struct intr_handler *ih;
+	char *last;
+	int missed, space;
+
+	/* Start off with no entropy and just the name of the event. */
+	mtx_assert(&ie->ie_lock, MA_OWNED);
+	strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
+	ie->ie_flags &= ~IE_ENTROPY;
+	missed = 0;
+	space = 1;
+
+	/* Run through all the handlers updating values. */
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
+		    sizeof(ie->ie_fullname)) {
+			strcat(ie->ie_fullname, " ");
+			strcat(ie->ie_fullname, ih->ih_name);
+			space = 0;
+		} else
+			missed++;
+		if (ih->ih_flags & IH_ENTROPY)
+			ie->ie_flags |= IE_ENTROPY;
+	}
+
+	/*
+	 * If the handler names were too long, add +'s to indicate missing
+	 * names. If we run out of room and still have +'s to add, change
+	 * the last character from a + to a *.
+	 */
+	last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
+	while (missed-- > 0) {
+		if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
+			if (*last == '+') {
+				*last = '*';
+				break;
+			} else
+				*last = '+';
+		} else if (space) {
+			strcat(ie->ie_fullname, " +");
+			space = 0;
+		} else
+			strcat(ie->ie_fullname, "+");
+	}
+
+	/*
+	 * If this event has an ithread, update it's priority and
+	 * name.
+	 */
+	if (ie->ie_thread != NULL)
+		ithread_update(ie->ie_thread);
+	CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
+}
+#ifndef __rtems__
+
+int
+intr_event_create(struct intr_event **event, void *source, int flags, int irq,
+    void (*pre_ithread)(void *), void (*post_ithread)(void *),
+    void (*post_filter)(void *), int (*assign_cpu)(void *, u_char),
+    const char *fmt, ...)
+{
+	struct intr_event *ie;
+	va_list ap;
+
+	/* The only valid flag during creation is IE_SOFT. */
+	if ((flags & ~IE_SOFT) != 0)
+		return (EINVAL);
+	ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
+	ie->ie_source = source;
+	ie->ie_pre_ithread = pre_ithread;
+	ie->ie_post_ithread = post_ithread;
+	ie->ie_post_filter = post_filter;
+	ie->ie_assign_cpu = assign_cpu;
+	ie->ie_flags = flags;
+	ie->ie_irq = irq;
+	ie->ie_cpu = NOCPU;
+	TAILQ_INIT(&ie->ie_handlers);
+	mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
+
+	va_start(ap, fmt);
+	vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
+	va_end(ap);
+	strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
+	mtx_lock(&event_lock);
+	TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
+	mtx_unlock(&event_lock);
+	if (event != NULL)
+		*event = ie;
+	CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
+	return (0);
+}
+
+/*
+ * Bind an interrupt event to the specified CPU.  Note that not all
+ * platforms support binding an interrupt to a CPU.  For those
+ * platforms this request will fail.  For supported platforms, any
+ * associated ithreads as well as the primary interrupt context will
+ * be bound to the specificed CPU.  Using a cpu id of NOCPU unbinds
+ * the interrupt event.
+ */
+int
+intr_event_bind(struct intr_event *ie, u_char cpu)
+{
+	cpuset_t mask;
+	lwpid_t id;
+	int error;
+
+	/* Need a CPU to bind to. */
+	if (cpu != NOCPU && CPU_ABSENT(cpu))
+		return (EINVAL);
+
+	if (ie->ie_assign_cpu == NULL)
+		return (EOPNOTSUPP);
+
+	error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
+	if (error)
+		return (error);
+
+	/*
+	 * If we have any ithreads try to set their mask first to verify
+	 * permissions, etc.
+	 */
+	mtx_lock(&ie->ie_lock);
+	if (ie->ie_thread != NULL) {
+		CPU_ZERO(&mask);
+		if (cpu == NOCPU)
+			CPU_COPY(cpuset_root, &mask);
+		else
+			CPU_SET(cpu, &mask);
+		id = ie->ie_thread->it_thread->td_tid;
+		mtx_unlock(&ie->ie_lock);
+		error = cpuset_setthread(id, &mask);
+		if (error)
+			return (error);
+	} else
+		mtx_unlock(&ie->ie_lock);
+	error = ie->ie_assign_cpu(ie->ie_source, cpu);
+	if (error) {
+		mtx_lock(&ie->ie_lock);
+		if (ie->ie_thread != NULL) {
+			CPU_ZERO(&mask);
+			if (ie->ie_cpu == NOCPU)
+				CPU_COPY(cpuset_root, &mask);
+			else
+				CPU_SET(cpu, &mask);
+			id = ie->ie_thread->it_thread->td_tid;
+			mtx_unlock(&ie->ie_lock);
+			(void)cpuset_setthread(id, &mask);
+		} else
+			mtx_unlock(&ie->ie_lock);
+		return (error);
+	}
+
+	mtx_lock(&ie->ie_lock);
+	ie->ie_cpu = cpu;
+	mtx_unlock(&ie->ie_lock);
+
+	return (error);
+}
+
+static struct intr_event *
+intr_lookup(int irq)
+{
+	struct intr_event *ie;
+
+	mtx_lock(&event_lock);
+	TAILQ_FOREACH(ie, &event_list, ie_list)
+		if (ie->ie_irq == irq &&
+		    (ie->ie_flags & IE_SOFT) == 0 &&
+		    TAILQ_FIRST(&ie->ie_handlers) != NULL)
+			break;
+	mtx_unlock(&event_lock);
+	return (ie);
+}
+
+int
+intr_setaffinity(int irq, void *m)
+{
+	struct intr_event *ie;
+	cpuset_t *mask;
+	u_char cpu;
+	int n;
+
+	mask = m;
+	cpu = NOCPU;
+	/*
+	 * If we're setting all cpus we can unbind.  Otherwise make sure
+	 * only one cpu is in the set.
+	 */
+	if (CPU_CMP(cpuset_root, mask)) {
+		for (n = 0; n < CPU_SETSIZE; n++) {
+			if (!CPU_ISSET(n, mask))
+				continue;
+			if (cpu != NOCPU)
+				return (EINVAL);
+			cpu = (u_char)n;
+		}
+	}
+	ie = intr_lookup(irq);
+	if (ie == NULL)
+		return (ESRCH);
+	return (intr_event_bind(ie, cpu));
+}
+
+int
+intr_getaffinity(int irq, void *m)
+{
+	struct intr_event *ie;
+	cpuset_t *mask;
+
+	mask = m;
+	ie = intr_lookup(irq);
+	if (ie == NULL)
+		return (ESRCH);
+	CPU_ZERO(mask);
+	mtx_lock(&ie->ie_lock);
+	if (ie->ie_cpu == NOCPU)
+		CPU_COPY(cpuset_root, mask);
+	else
+		CPU_SET(ie->ie_cpu, mask);
+	mtx_unlock(&ie->ie_lock);
+	return (0);
+}
+
+int
+intr_event_destroy(struct intr_event *ie)
+{
+
+	mtx_lock(&event_lock);
+	mtx_lock(&ie->ie_lock);
+	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
+		mtx_unlock(&ie->ie_lock);
+		mtx_unlock(&event_lock);
+		return (EBUSY);
+	}
+	TAILQ_REMOVE(&event_list, ie, ie_list);
+#ifndef notyet
+	if (ie->ie_thread != NULL) {
+		ithread_destroy(ie->ie_thread);
+		ie->ie_thread = NULL;
+	}
+#endif
+	mtx_unlock(&ie->ie_lock);
+	mtx_unlock(&event_lock);
+	mtx_destroy(&ie->ie_lock);
+	free(ie, M_ITHREAD);
+	return (0);
+}
+
+#ifndef INTR_FILTER
+static struct intr_thread *
+ithread_create(const char *name)
+{
+	struct intr_thread *ithd;
+	struct thread *td;
+	int error;
+
+	ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
+
+	error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
+		    &td, RFSTOPPED | RFHIGHPID,
+	    	    0, "intr", "%s", name);
+	if (error)
+		panic("kproc_create() failed with %d", error);
+	thread_lock(td);
+	sched_class(td, PRI_ITHD);
+	TD_SET_IWAIT(td);
+	thread_unlock(td);
+	td->td_pflags |= TDP_ITHREAD;
+	ithd->it_thread = td;
+	CTR2(KTR_INTR, "%s: created %s", __func__, name);
+	return (ithd);
+}
+#else
+static struct intr_thread *
+ithread_create(const char *name, struct intr_handler *ih)
+{
+	struct intr_thread *ithd;
+	struct thread *td;
+	int error;
+
+	ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
+
+	error = kproc_kthread_add(ithread_loop, ih, &intrproc,
+		    &td, RFSTOPPED | RFHIGHPID,
+	    	    0, "intr", "%s", name);
+	if (error)
+		panic("kproc_create() failed with %d", error);
+	thread_lock(td);
+	sched_class(td, PRI_ITHD);
+	TD_SET_IWAIT(td);
+	thread_unlock(td);
+	td->td_pflags |= TDP_ITHREAD;
+	ithd->it_thread = td;
+	CTR2(KTR_INTR, "%s: created %s", __func__, name);
+	return (ithd);
+}
+#endif
+
+static void
+ithread_destroy(struct intr_thread *ithread)
+{
+	struct thread *td;
+
+	CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name);
+	td = ithread->it_thread;
+	thread_lock(td);
+	ithread->it_flags |= IT_DEAD;
+	if (TD_AWAITING_INTR(td)) {
+		TD_CLR_IWAIT(td);
+		sched_add(td, SRQ_INTR);
+	}
+	thread_unlock(td);
+}
+#endif /* __rtems__ */
+
+#ifndef INTR_FILTER
+int
+intr_event_add_handler(struct intr_event *ie, const char *name,
+    driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
+    enum intr_type flags, void **cookiep)
+{
+	struct intr_handler *ih, *temp_ih;
+	struct intr_thread *it;
+
+	if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
+		return (EINVAL);
+
+	/* Allocate and populate an interrupt handler structure. */
+	ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
+	ih->ih_filter = filter;
+	ih->ih_handler = handler;
+	ih->ih_argument = arg;
+	strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
+	ih->ih_event = ie;
+	ih->ih_pri = pri;
+	if (flags & INTR_EXCL)
+		ih->ih_flags = IH_EXCLUSIVE;
+	if (flags & INTR_MPSAFE)
+		ih->ih_flags |= IH_MPSAFE;
+	if (flags & INTR_ENTROPY)
+		ih->ih_flags |= IH_ENTROPY;
+
+	/* We can only have one exclusive handler in a event. */
+	mtx_lock(&ie->ie_lock);
+	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
+		if ((flags & INTR_EXCL) ||
+		    (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
+			mtx_unlock(&ie->ie_lock);
+			free(ih, M_ITHREAD);
+			return (EINVAL);
+		}
+	}
+
+	/* Add the new handler to the event in priority order. */
+	TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) {
+		if (temp_ih->ih_pri > ih->ih_pri)
+			break;
+	}
+	if (temp_ih == NULL)
+		TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next);
+	else
+		TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
+	intr_event_update(ie);
+
+	/* Create a thread if we need one. */
+	while (ie->ie_thread == NULL && handler != NULL) {
+		if (ie->ie_flags & IE_ADDING_THREAD)
+			msleep(ie, &ie->ie_lock, 0, "ithread", 0);
+		else {
+			ie->ie_flags |= IE_ADDING_THREAD;
+			mtx_unlock(&ie->ie_lock);
+			it = ithread_create("intr: newborn");
+			mtx_lock(&ie->ie_lock);
+			ie->ie_flags &= ~IE_ADDING_THREAD;
+			ie->ie_thread = it;
+			it->it_event = ie;
+			ithread_update(it);
+			wakeup(ie);
+		}
+	}
+	CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
+	    ie->ie_name);
+	mtx_unlock(&ie->ie_lock);
+
+	if (cookiep != NULL)
+		*cookiep = ih;
+	return (0);
+}
+#else
+int
+intr_event_add_handler(struct intr_event *ie, const char *name,
+    driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
+    enum intr_type flags, void **cookiep)
+{
+	struct intr_handler *ih, *temp_ih;
+	struct intr_thread *it;
+
+	if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
+		return (EINVAL);
+
+	/* Allocate and populate an interrupt handler structure. */
+	ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
+	ih->ih_filter = filter;
+	ih->ih_handler = handler;
+	ih->ih_argument = arg;
+	strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
+	ih->ih_event = ie;
+	ih->ih_pri = pri;
+	if (flags & INTR_EXCL)
+		ih->ih_flags = IH_EXCLUSIVE;
+	if (flags & INTR_MPSAFE)
+		ih->ih_flags |= IH_MPSAFE;
+	if (flags & INTR_ENTROPY)
+		ih->ih_flags |= IH_ENTROPY;
+
+	/* We can only have one exclusive handler in a event. */
+	mtx_lock(&ie->ie_lock);
+	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
+		if ((flags & INTR_EXCL) ||
+		    (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
+			mtx_unlock(&ie->ie_lock);
+			free(ih, M_ITHREAD);
+			return (EINVAL);
+		}
+	}
+
+	/* Add the new handler to the event in priority order. */
+	TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) {
+		if (temp_ih->ih_pri > ih->ih_pri)
+			break;
+	}
+	if (temp_ih == NULL)
+		TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next);
+	else
+		TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
+	intr_event_update(ie);
+
+	/* For filtered handlers, create a private ithread to run on. */
+	if (filter != NULL && handler != NULL) { 
+		mtx_unlock(&ie->ie_lock);
+		it = ithread_create("intr: newborn", ih);		
+		mtx_lock(&ie->ie_lock);
+		it->it_event = ie; 
+		ih->ih_thread = it;
+		ithread_update(it); // XXX - do we really need this?!?!?
+	} else { /* Create the global per-event thread if we need one. */
+		while (ie->ie_thread == NULL && handler != NULL) {
+			if (ie->ie_flags & IE_ADDING_THREAD)
+				msleep(ie, &ie->ie_lock, 0, "ithread", 0);
+			else {
+				ie->ie_flags |= IE_ADDING_THREAD;
+				mtx_unlock(&ie->ie_lock);
+				it = ithread_create("intr: newborn", ih);
+				mtx_lock(&ie->ie_lock);
+				ie->ie_flags &= ~IE_ADDING_THREAD;
+				ie->ie_thread = it;
+				it->it_event = ie;
+				ithread_update(it);
+				wakeup(ie);
+			}
+		}
+	}
+	CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
+	    ie->ie_name);
+	mtx_unlock(&ie->ie_lock);
+
+	if (cookiep != NULL)
+		*cookiep = ih;
+	return (0);
+}
+#endif
+
+#ifndef __rtems__
+/*
+ * Append a description preceded by a ':' to the name of the specified
+ * interrupt handler.
+ */
+int
+intr_event_describe_handler(struct intr_event *ie, void *cookie,
+    const char *descr)
+{
+	struct intr_handler *ih;
+	size_t space;
+	char *start;
+
+	mtx_lock(&ie->ie_lock);
+#ifdef INVARIANTS
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (ih == cookie)
+			break;
+	}
+	if (ih == NULL) {
+		mtx_unlock(&ie->ie_lock);
+		panic("handler %p not found in interrupt event %p", cookie, ie);
+	}
+#endif
+	ih = cookie;
+
+	/*
+	 * Look for an existing description by checking for an
+	 * existing ":".  This assumes device names do not include
+	 * colons.  If one is found, prepare to insert the new
+	 * description at that point.  If one is not found, find the
+	 * end of the name to use as the insertion point.
+	 */
+	start = index(ih->ih_name, ':');
+	if (start == NULL)
+		start = index(ih->ih_name, 0);
+
+	/*
+	 * See if there is enough remaining room in the string for the
+	 * description + ":".  The "- 1" leaves room for the trailing
+	 * '\0'.  The "+ 1" accounts for the colon.
+	 */
+	space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
+	if (strlen(descr) + 1 > space) {
+		mtx_unlock(&ie->ie_lock);
+		return (ENOSPC);
+	}
+
+	/* Append a colon followed by the description. */
+	*start = ':';
+	strcpy(start + 1, descr);
+	intr_event_update(ie);
+	mtx_unlock(&ie->ie_lock);
+	return (0);
+}
+
+/*
+ * Return the ie_source field from the intr_event an intr_handler is
+ * associated with.
+ */
+void *
+intr_handler_source(void *cookie)
+{
+	struct intr_handler *ih;
+	struct intr_event *ie;
+
+	ih = (struct intr_handler *)cookie;
+	if (ih == NULL)
+		return (NULL);
+	ie = ih->ih_event;
+	KASSERT(ie != NULL,
+	    ("interrupt handler \"%s\" has a NULL interrupt event",
+	    ih->ih_name));
+	return (ie->ie_source);
+}
+
+#ifndef INTR_FILTER
+int
+intr_event_remove_handler(void *cookie)
+{
+	struct intr_handler *handler = (struct intr_handler *)cookie;
+	struct intr_event *ie;
+#ifdef INVARIANTS
+	struct intr_handler *ih;
+#endif
+#ifdef notyet
+	int dead;
+#endif
+
+	if (handler == NULL)
+		return (EINVAL);
+	ie = handler->ih_event;
+	KASSERT(ie != NULL,
+	    ("interrupt handler \"%s\" has a NULL interrupt event",
+	    handler->ih_name));
+	mtx_lock(&ie->ie_lock);
+	CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
+	    ie->ie_name);
+#ifdef INVARIANTS
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
+		if (ih == handler)
+			goto ok;
+	mtx_unlock(&ie->ie_lock);
+	panic("interrupt handler \"%s\" not found in interrupt event \"%s\"",
+	    ih->ih_name, ie->ie_name);
+ok:
+#endif
+	/*
+	 * If there is no ithread, then just remove the handler and return.
+	 * XXX: Note that an INTR_FAST handler might be running on another
+	 * CPU!
+	 */
+	if (ie->ie_thread == NULL) {
+		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
+		mtx_unlock(&ie->ie_lock);
+		free(handler, M_ITHREAD);
+		return (0);
+	}
+
+	/*
+	 * If the interrupt thread is already running, then just mark this
+	 * handler as being dead and let the ithread do the actual removal.
+	 *
+	 * During a cold boot while cold is set, msleep() does not sleep,
+	 * so we have to remove the handler here rather than letting the
+	 * thread do it.
+	 */
+	thread_lock(ie->ie_thread->it_thread);
+	if (!TD_AWAITING_INTR(ie->ie_thread->it_thread) && !cold) {
+		handler->ih_flags |= IH_DEAD;
+
+		/*
+		 * Ensure that the thread will process the handler list
+		 * again and remove this handler if it has already passed
+		 * it on the list.
+		 */
+		ie->ie_thread->it_need = 1;
+	} else
+		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
+	thread_unlock(ie->ie_thread->it_thread);
+	while (handler->ih_flags & IH_DEAD)
+		msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
+	intr_event_update(ie);
+#ifdef notyet
+	/*
+	 * XXX: This could be bad in the case of ppbus(8).  Also, I think
+	 * this could lead to races of stale data when servicing an
+	 * interrupt.
+	 */
+	dead = 1;
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (!(ih->ih_flags & IH_FAST)) {
+			dead = 0;
+			break;
+		}
+	}
+	if (dead) {
+		ithread_destroy(ie->ie_thread);
+		ie->ie_thread = NULL;
+	}
+#endif
+	mtx_unlock(&ie->ie_lock);
+	free(handler, M_ITHREAD);
+	return (0);
+}
+
+static int
+intr_event_schedule_thread(struct intr_event *ie)
+{
+	struct intr_entropy entropy;
+	struct intr_thread *it;
+	struct thread *td;
+	struct thread *ctd;
+	struct proc *p;
+
+	/*
+	 * If no ithread or no handlers, then we have a stray interrupt.
+	 */
+	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) ||
+	    ie->ie_thread == NULL)
+		return (EINVAL);
+
+	ctd = curthread;
+	it = ie->ie_thread;
+	td = it->it_thread;
+	p = td->td_proc;
+
+	/*
+	 * If any of the handlers for this ithread claim to be good
+	 * sources of entropy, then gather some.
+	 */
+	if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) {
+		CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__,
+		    p->p_pid, td->td_name);
+		entropy.event = (uintptr_t)ie;
+		entropy.td = ctd;
+		random_harvest(&entropy, sizeof(entropy), 2, 0,
+		    RANDOM_INTERRUPT);
+	}
+
+	KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name));
+
+	/*
+	 * Set it_need to tell the thread to keep running if it is already
+	 * running.  Then, lock the thread and see if we actually need to
+	 * put it on the runqueue.
+	 */
+	it->it_need = 1;
+	thread_lock(td);
+	if (TD_AWAITING_INTR(td)) {
+		CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
+		    td->td_name);
+		TD_CLR_IWAIT(td);
+		sched_add(td, SRQ_INTR);
+	} else {
+		CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
+		    __func__, p->p_pid, td->td_name, it->it_need, td->td_state);
+	}
+	thread_unlock(td);
+
+	return (0);
+}
+#else
+int
+intr_event_remove_handler(void *cookie)
+{
+	struct intr_handler *handler = (struct intr_handler *)cookie;
+	struct intr_event *ie;
+	struct intr_thread *it;
+#ifdef INVARIANTS
+	struct intr_handler *ih;
+#endif
+#ifdef notyet
+	int dead;
+#endif
+
+	if (handler == NULL)
+		return (EINVAL);
+	ie = handler->ih_event;
+	KASSERT(ie != NULL,
+	    ("interrupt handler \"%s\" has a NULL interrupt event",
+	    handler->ih_name));
+	mtx_lock(&ie->ie_lock);
+	CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
+	    ie->ie_name);
+#ifdef INVARIANTS
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
+		if (ih == handler)
+			goto ok;
+	mtx_unlock(&ie->ie_lock);
+	panic("interrupt handler \"%s\" not found in interrupt event \"%s\"",
+	    ih->ih_name, ie->ie_name);
+ok:
+#endif
+	/*
+	 * If there are no ithreads (per event and per handler), then
+	 * just remove the handler and return.  
+	 * XXX: Note that an INTR_FAST handler might be running on another CPU!
+	 */
+	if (ie->ie_thread == NULL && handler->ih_thread == NULL) {
+		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
+		mtx_unlock(&ie->ie_lock);
+		free(handler, M_ITHREAD);
+		return (0);
+	}
+
+	/* Private or global ithread? */
+	it = (handler->ih_thread) ? handler->ih_thread : ie->ie_thread;
+	/*
+	 * If the interrupt thread is already running, then just mark this
+	 * handler as being dead and let the ithread do the actual removal.
+	 *
+	 * During a cold boot while cold is set, msleep() does not sleep,
+	 * so we have to remove the handler here rather than letting the
+	 * thread do it.
+	 */
+	thread_lock(it->it_thread);
+	if (!TD_AWAITING_INTR(it->it_thread) && !cold) {
+		handler->ih_flags |= IH_DEAD;
+
+		/*
+		 * Ensure that the thread will process the handler list
+		 * again and remove this handler if it has already passed
+		 * it on the list.
+		 */
+		it->it_need = 1;
+	} else
+		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
+	thread_unlock(it->it_thread);
+	while (handler->ih_flags & IH_DEAD)
+		msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
+	/* 
+	 * At this point, the handler has been disconnected from the event,
+	 * so we can kill the private ithread if any.
+	 */
+	if (handler->ih_thread) {
+		ithread_destroy(handler->ih_thread);
+		handler->ih_thread = NULL;
+	}
+	intr_event_update(ie);
+#ifdef notyet
+	/*
+	 * XXX: This could be bad in the case of ppbus(8).  Also, I think
+	 * this could lead to races of stale data when servicing an
+	 * interrupt.
+	 */
+	dead = 1;
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (handler != NULL) {
+			dead = 0;
+			break;
+		}
+	}
+	if (dead) {
+		ithread_destroy(ie->ie_thread);
+		ie->ie_thread = NULL;
+	}
+#endif
+	mtx_unlock(&ie->ie_lock);
+	free(handler, M_ITHREAD);
+	return (0);
+}
+
+static int
+intr_event_schedule_thread(struct intr_event *ie, struct intr_thread *it)
+{
+	struct intr_entropy entropy;
+	struct thread *td;
+	struct thread *ctd;
+	struct proc *p;
+
+	/*
+	 * If no ithread or no handlers, then we have a stray interrupt.
+	 */
+	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) || it == NULL)
+		return (EINVAL);
+
+	ctd = curthread;
+	td = it->it_thread;
+	p = td->td_proc;
+
+	/*
+	 * If any of the handlers for this ithread claim to be good
+	 * sources of entropy, then gather some.
+	 */
+	if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) {
+		CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__,
+		    p->p_pid, td->td_name);
+		entropy.event = (uintptr_t)ie;
+		entropy.td = ctd;
+		random_harvest(&entropy, sizeof(entropy), 2, 0,
+		    RANDOM_INTERRUPT);
+	}
+
+	KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name));
+
+	/*
+	 * Set it_need to tell the thread to keep running if it is already
+	 * running.  Then, lock the thread and see if we actually need to
+	 * put it on the runqueue.
+	 */
+	it->it_need = 1;
+	thread_lock(td);
+	if (TD_AWAITING_INTR(td)) {
+		CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
+		    td->td_name);
+		TD_CLR_IWAIT(td);
+		sched_add(td, SRQ_INTR);
+	} else {
+		CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
+		    __func__, p->p_pid, td->td_name, it->it_need, td->td_state);
+	}
+	thread_unlock(td);
+
+	return (0);
+}
+#endif
+#endif /* __rtems__ */
+
+/*
+ * Allow interrupt event binding for software interrupt handlers -- a no-op,
+ * since interrupts are generated in software rather than being directed by
+ * a PIC.
+ */
+static int
+swi_assign_cpu(void *arg, u_char cpu)
+{
+
+	return (0);
+}
+
+/*
+ * Add a software interrupt handler to a specified event.  If a given event
+ * is not specified, then a new event is created.
+ */
+int
+swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
+	    void *arg, int pri, enum intr_type flags, void **cookiep)
+{
+	struct intr_event *ie;
+	int error;
+
+	if (flags & INTR_ENTROPY)
+		return (EINVAL);
+
+	ie = (eventp != NULL) ? *eventp : NULL;
+
+	if (ie != NULL) {
+		if (!(ie->ie_flags & IE_SOFT))
+			return (EINVAL);
+	} else {
+		error = intr_event_create(&ie, NULL, IE_SOFT, 0,
+		    NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
+		if (error)
+			return (error);
+		if (eventp != NULL)
+			*eventp = ie;
+	}
+	error = intr_event_add_handler(ie, name, NULL, handler, arg,
+	    (pri * RQ_PPQ) + PI_SOFT, flags, cookiep);
+	if (error)
+		return (error);
+	if (pri == SWI_CLOCK) {
+		struct proc *p;
+		p = ie->ie_thread->it_thread->td_proc;
+		PROC_LOCK(p);
+#ifndef __rtems__
+		p->p_flag |= P_NOLOAD;
+#endif /* __rtems__ */
+		PROC_UNLOCK(p);
+	}
+	return (0);
+}
+
+#ifndef __rtems__
+/*
+ * Schedule a software interrupt thread.
+ */
+void
+swi_sched(void *cookie, int flags)
+{
+	struct intr_handler *ih = (struct intr_handler *)cookie;
+	struct intr_event *ie = ih->ih_event;
+	int error;
+
+	CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
+	    ih->ih_need);
+
+	/*
+	 * Set ih_need for this handler so that if the ithread is already
+	 * running it will execute this handler on the next pass.  Otherwise,
+	 * it will execute it the next time it runs.
+	 */
+	atomic_store_rel_int(&ih->ih_need, 1);
+
+	if (!(flags & SWI_DELAY)) {
+		PCPU_INC(cnt.v_soft);
+#ifdef INTR_FILTER
+		error = intr_event_schedule_thread(ie, ie->ie_thread);
+#else
+		error = intr_event_schedule_thread(ie);
+#endif
+		KASSERT(error == 0, ("stray software interrupt"));
+	}
+}
+
+/*
+ * Remove a software interrupt handler.  Currently this code does not
+ * remove the associated interrupt event if it becomes empty.  Calling code
+ * may do so manually via intr_event_destroy(), but that's not really
+ * an optimal interface.
+ */
+int
+swi_remove(void *cookie)
+{
+
+	return (intr_event_remove_handler(cookie));
+}
+
+#ifdef INTR_FILTER
+static void
+priv_ithread_execute_handler(struct proc *p, struct intr_handler *ih)
+{
+	struct intr_event *ie;
+
+	ie = ih->ih_event;
+	/*
+	 * If this handler is marked for death, remove it from
+	 * the list of handlers and wake up the sleeper.
+	 */
+	if (ih->ih_flags & IH_DEAD) {
+		mtx_lock(&ie->ie_lock);
+		TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next);
+		ih->ih_flags &= ~IH_DEAD;
+		wakeup(ih);
+		mtx_unlock(&ie->ie_lock);
+		return;
+	}
+	
+	/* Execute this handler. */
+	CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
+	     __func__, p->p_pid, (void *)ih->ih_handler, ih->ih_argument,
+	     ih->ih_name, ih->ih_flags);
+	
+	if (!(ih->ih_flags & IH_MPSAFE))
+		mtx_lock(&Giant);
+	ih->ih_handler(ih->ih_argument);
+	if (!(ih->ih_flags & IH_MPSAFE))
+		mtx_unlock(&Giant);
+}
+#endif
+
+/*
+ * This is a public function for use by drivers that mux interrupt
+ * handlers for child devices from their interrupt handler.
+ */
+void
+intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
+{
+	struct intr_handler *ih, *ihn;
+
+	TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
+		/*
+		 * If this handler is marked for death, remove it from
+		 * the list of handlers and wake up the sleeper.
+		 */
+		if (ih->ih_flags & IH_DEAD) {
+			mtx_lock(&ie->ie_lock);
+			TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next);
+			ih->ih_flags &= ~IH_DEAD;
+			wakeup(ih);
+			mtx_unlock(&ie->ie_lock);
+			continue;
+		}
+
+		/* Skip filter only handlers */
+		if (ih->ih_handler == NULL)
+			continue;
+
+		/*
+		 * For software interrupt threads, we only execute
+		 * handlers that have their need flag set.  Hardware
+		 * interrupt threads always invoke all of their handlers.
+		 */
+		if (ie->ie_flags & IE_SOFT) {
+			if (!ih->ih_need)
+				continue;
+			else
+				atomic_store_rel_int(&ih->ih_need, 0);
+		}
+
+		/* Execute this handler. */
+		CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
+		    __func__, p->p_pid, (void *)ih->ih_handler, 
+		    ih->ih_argument, ih->ih_name, ih->ih_flags);
+
+		if (!(ih->ih_flags & IH_MPSAFE))
+			mtx_lock(&Giant);
+		ih->ih_handler(ih->ih_argument);
+		if (!(ih->ih_flags & IH_MPSAFE))
+			mtx_unlock(&Giant);
+	}
+}
+
+static void
+ithread_execute_handlers(struct proc *p, struct intr_event *ie)
+{
+
+	/* Interrupt handlers should not sleep. */
+	if (!(ie->ie_flags & IE_SOFT))
+		THREAD_NO_SLEEPING();
+	intr_event_execute_handlers(p, ie);
+	if (!(ie->ie_flags & IE_SOFT))
+		THREAD_SLEEPING_OK();
+
+	/*
+	 * Interrupt storm handling:
+	 *
+	 * If this interrupt source is currently storming, then throttle
+	 * it to only fire the handler once  per clock tick.
+	 *
+	 * If this interrupt source is not currently storming, but the
+	 * number of back to back interrupts exceeds the storm threshold,
+	 * then enter storming mode.
+	 */
+	if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold &&
+	    !(ie->ie_flags & IE_SOFT)) {
+		/* Report the message only once every second. */
+		if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
+			printf(
+	"interrupt storm detected on \"%s\"; throttling interrupt source\n",
+			    ie->ie_name);
+		}
+		pause("istorm", 1);
+	} else
+		ie->ie_count++;
+
+	/*
+	 * Now that all the handlers have had a chance to run, reenable
+	 * the interrupt source.
+	 */
+	if (ie->ie_post_ithread != NULL)
+		ie->ie_post_ithread(ie->ie_source);
+}
+
+#ifndef INTR_FILTER
+/*
+ * This is the main code for interrupt threads.
+ */
+static void
+ithread_loop(void *arg)
+{
+	struct intr_thread *ithd;
+	struct intr_event *ie;
+	struct thread *td;
+	struct proc *p;
+
+	td = curthread;
+	p = td->td_proc;
+	ithd = (struct intr_thread *)arg;
+	KASSERT(ithd->it_thread == td,
+	    ("%s: ithread and proc linkage out of sync", __func__));
+	ie = ithd->it_event;
+	ie->ie_count = 0;
+
+	/*
+	 * As long as we have interrupts outstanding, go through the
+	 * list of handlers, giving each one a go at it.
+	 */
+	for (;;) {
+		/*
+		 * If we are an orphaned thread, then just die.
+		 */
+		if (ithd->it_flags & IT_DEAD) {
+			CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
+			    p->p_pid, td->td_name);
+			free(ithd, M_ITHREAD);
+			kthread_exit();
+		}
+
+		/*
+		 * Service interrupts.  If another interrupt arrives while
+		 * we are running, it will set it_need to note that we
+		 * should make another pass.
+		 */
+		while (ithd->it_need) {
+			/*
+			 * This might need a full read and write barrier
+			 * to make sure that this write posts before any
+			 * of the memory or device accesses in the
+			 * handlers.
+			 */
+			atomic_store_rel_int(&ithd->it_need, 0);
+			ithread_execute_handlers(p, ie);
+		}
+		WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
+		mtx_assert(&Giant, MA_NOTOWNED);
+
+		/*
+		 * Processed all our interrupts.  Now get the sched
+		 * lock.  This may take a while and it_need may get
+		 * set again, so we have to check it again.
+		 */
+		thread_lock(td);
+		if (!ithd->it_need && !(ithd->it_flags & IT_DEAD)) {
+			TD_SET_IWAIT(td);
+			ie->ie_count = 0;
+			mi_switch(SW_VOL | SWT_IWAIT, NULL);
+		}
+		thread_unlock(td);
+	}
+}
+
+/*
+ * Main interrupt handling body.
+ *
+ * Input:
+ * o ie:                        the event connected to this interrupt.
+ * o frame:                     some archs (i.e. i386) pass a frame to some.
+ *                              handlers as their main argument.
+ * Return value:
+ * o 0:                         everything ok.
+ * o EINVAL:                    stray interrupt.
+ */
+int
+intr_event_handle(struct intr_event *ie, struct trapframe *frame)
+{
+	struct intr_handler *ih;
+	struct thread *td;
+	int error, ret, thread;
+
+	td = curthread;
+
+	/* An interrupt with no event or handlers is a stray interrupt. */
+	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
+		return (EINVAL);
+
+	/*
+	 * 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.
+	 */
+	td->td_intr_nesting_level++;
+	thread = 0;
+	ret = 0;
+	critical_enter();
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (ih->ih_filter == NULL) {
+			thread = 1;
+			continue;
+		}
+		CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
+		    ih->ih_filter, ih->ih_argument == NULL ? frame :
+		    ih->ih_argument, ih->ih_name);
+		if (ih->ih_argument == NULL)
+			ret = ih->ih_filter(frame);
+		else
+			ret = ih->ih_filter(ih->ih_argument);
+		KASSERT(ret == FILTER_STRAY ||
+		    ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
+		    (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
+		    ("%s: incorrect return value %#x from %s", __func__, ret,
+		    ih->ih_name));
+
+		/* 
+		 * Wrapper handler special handling:
+		 *
+		 * in some particular cases (like pccard and pccbb), 
+		 * the _real_ device handler is wrapped in a couple of
+		 * functions - a filter wrapper and an ithread wrapper.
+		 * In this case (and just in this case), the filter wrapper 
+		 * could ask the system to schedule the ithread and mask
+		 * the interrupt source if the wrapped handler is composed
+		 * of just an ithread handler.
+		 *
+		 * TODO: write a generic wrapper to avoid people rolling 
+		 * their own
+		 */
+		if (!thread) {
+			if (ret == FILTER_SCHEDULE_THREAD)
+				thread = 1;
+		}
+	}
+
+	if (thread) {
+		if (ie->ie_pre_ithread != NULL)
+			ie->ie_pre_ithread(ie->ie_source);
+	} else {
+		if (ie->ie_post_filter != NULL)
+			ie->ie_post_filter(ie->ie_source);
+	}
+	
+	/* Schedule the ithread if needed. */
+	if (thread) {
+		error = intr_event_schedule_thread(ie);
+#ifndef XEN		
+		KASSERT(error == 0, ("bad stray interrupt"));
+#else
+		if (error != 0)
+			log(LOG_WARNING, "bad stray interrupt");
+#endif		
+	}
+	critical_exit();
+	td->td_intr_nesting_level--;
+	return (0);
+}
+#else
+/*
+ * This is the main code for interrupt threads.
+ */
+static void
+ithread_loop(void *arg)
+{
+	struct intr_thread *ithd;
+	struct intr_handler *ih;
+	struct intr_event *ie;
+	struct thread *td;
+	struct proc *p;
+	int priv;
+
+	td = curthread;
+	p = td->td_proc;
+	ih = (struct intr_handler *)arg;
+	priv = (ih->ih_thread != NULL) ? 1 : 0;
+	ithd = (priv) ? ih->ih_thread : ih->ih_event->ie_thread;
+	KASSERT(ithd->it_thread == td,
+	    ("%s: ithread and proc linkage out of sync", __func__));
+	ie = ithd->it_event;
+	ie->ie_count = 0;
+
+	/*
+	 * As long as we have interrupts outstanding, go through the
+	 * list of handlers, giving each one a go at it.
+	 */
+	for (;;) {
+		/*
+		 * If we are an orphaned thread, then just die.
+		 */
+		if (ithd->it_flags & IT_DEAD) {
+			CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
+			    p->p_pid, td->td_name);
+			free(ithd, M_ITHREAD);
+			kthread_exit();
+		}
+
+		/*
+		 * Service interrupts.  If another interrupt arrives while
+		 * we are running, it will set it_need to note that we
+		 * should make another pass.
+		 */
+		while (ithd->it_need) {
+			/*
+			 * This might need a full read and write barrier
+			 * to make sure that this write posts before any
+			 * of the memory or device accesses in the
+			 * handlers.
+			 */
+			atomic_store_rel_int(&ithd->it_need, 0);
+			if (priv)
+				priv_ithread_execute_handler(p, ih);
+			else 
+				ithread_execute_handlers(p, ie);
+		}
+		WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
+		mtx_assert(&Giant, MA_NOTOWNED);
+
+		/*
+		 * Processed all our interrupts.  Now get the sched
+		 * lock.  This may take a while and it_need may get
+		 * set again, so we have to check it again.
+		 */
+		thread_lock(td);
+		if (!ithd->it_need && !(ithd->it_flags & IT_DEAD)) {
+			TD_SET_IWAIT(td);
+			ie->ie_count = 0;
+			mi_switch(SW_VOL | SWT_IWAIT, NULL);
+		}
+		thread_unlock(td);
+	}
+}
+
+/* 
+ * Main loop for interrupt filter.
+ *
+ * Some architectures (i386, amd64 and arm) require the optional frame 
+ * parameter, and use it as the main argument for fast handler execution
+ * when ih_argument == NULL.
+ *
+ * Return value:
+ * o FILTER_STRAY:              No filter recognized the event, and no
+ *                              filter-less handler is registered on this 
+ *                              line.
+ * o FILTER_HANDLED:            A filter claimed the event and served it.
+ * o FILTER_SCHEDULE_THREAD:    No filter claimed the event, but there's at
+ *                              least one filter-less handler on this line.
+ * o FILTER_HANDLED | 
+ *   FILTER_SCHEDULE_THREAD:    A filter claimed the event, and asked for
+ *                              scheduling the per-handler ithread.
+ *
+ * In case an ithread has to be scheduled, in *ithd there will be a 
+ * pointer to a struct intr_thread containing the thread to be
+ * scheduled.
+ */
+
+static int
+intr_filter_loop(struct intr_event *ie, struct trapframe *frame, 
+		 struct intr_thread **ithd) 
+{
+	struct intr_handler *ih;
+	void *arg;
+	int ret, thread_only;
+
+	ret = 0;
+	thread_only = 0;
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		/*
+		 * 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.
+		 */
+		arg = ((ih->ih_argument == NULL) ? frame : ih->ih_argument);
+		
+		CTR5(KTR_INTR, "%s: exec %p/%p(%p) for %s", __func__,
+		     ih->ih_filter, ih->ih_handler, arg, ih->ih_name);
+
+		if (ih->ih_filter != NULL)
+			ret = ih->ih_filter(arg);
+		else {
+			thread_only = 1;
+			continue;
+		}
+		KASSERT(ret == FILTER_STRAY ||
+		    ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
+		    (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
+		    ("%s: incorrect return value %#x from %s", __func__, ret,
+		    ih->ih_name));
+		if (ret & FILTER_STRAY)
+			continue;
+		else { 
+			*ithd = ih->ih_thread;
+			return (ret);
+		}
+	}
+
+	/*
+	 * No filters handled the interrupt and we have at least
+	 * one handler without a filter.  In this case, we schedule
+	 * all of the filter-less handlers to run in the ithread.
+	 */	
+	if (thread_only) {
+		*ithd = ie->ie_thread;
+		return (FILTER_SCHEDULE_THREAD);
+	}
+	return (FILTER_STRAY);
+}
+
+/*
+ * Main interrupt handling body.
+ *
+ * Input:
+ * o ie:                        the event connected to this interrupt.
+ * o frame:                     some archs (i.e. i386) pass a frame to some.
+ *                              handlers as their main argument.
+ * Return value:
+ * o 0:                         everything ok.
+ * o EINVAL:                    stray interrupt.
+ */
+int
+intr_event_handle(struct intr_event *ie, struct trapframe *frame)
+{
+	struct intr_thread *ithd;
+	struct thread *td;
+	int thread;
+
+	ithd = NULL;
+	td = curthread;
+
+	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
+		return (EINVAL);
+
+	td->td_intr_nesting_level++;
+	thread = 0;
+	critical_enter();
+	thread = intr_filter_loop(ie, frame, &ithd);	
+	if (thread & FILTER_HANDLED) {
+		if (ie->ie_post_filter != NULL)
+			ie->ie_post_filter(ie->ie_source);
+	} else {
+		if (ie->ie_pre_ithread != NULL)
+			ie->ie_pre_ithread(ie->ie_source);
+	}
+	critical_exit();
+	
+	/* Interrupt storm logic */
+	if (thread & FILTER_STRAY) {
+		ie->ie_count++;
+		if (ie->ie_count < intr_storm_threshold)
+			printf("Interrupt stray detection not present\n");
+	}
+
+	/* Schedule an ithread if needed. */
+	if (thread & FILTER_SCHEDULE_THREAD) {
+		if (intr_event_schedule_thread(ie, ithd) != 0)
+			panic("%s: impossible stray interrupt", __func__);
+	}
+	td->td_intr_nesting_level--;
+	return (0);
+}
+#endif
+
+#ifdef DDB
+/*
+ * Dump details about an interrupt handler
+ */
+static void
+db_dump_intrhand(struct intr_handler *ih)
+{
+	int comma;
+
+	db_printf("\t%-10s ", ih->ih_name);
+	switch (ih->ih_pri) {
+	case PI_REALTIME:
+		db_printf("CLK ");
+		break;
+	case PI_AV:
+		db_printf("AV  ");
+		break;
+	case PI_TTYHIGH:
+	case PI_TTYLOW:
+		db_printf("TTY ");
+		break;
+	case PI_TAPE:
+		db_printf("TAPE");
+		break;
+	case PI_NET:
+		db_printf("NET ");
+		break;
+	case PI_DISK:
+	case PI_DISKLOW:
+		db_printf("DISK");
+		break;
+	case PI_DULL:
+		db_printf("DULL");
+		break;
+	default:
+		if (ih->ih_pri >= PI_SOFT)
+			db_printf("SWI ");
+		else
+			db_printf("%4u", ih->ih_pri);
+		break;
+	}
+	db_printf(" ");
+	db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
+	db_printf("(%p)", ih->ih_argument);
+	if (ih->ih_need ||
+	    (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
+	    IH_MPSAFE)) != 0) {
+		db_printf(" {");
+		comma = 0;
+		if (ih->ih_flags & IH_EXCLUSIVE) {
+			if (comma)
+				db_printf(", ");
+			db_printf("EXCL");
+			comma = 1;
+		}
+		if (ih->ih_flags & IH_ENTROPY) {
+			if (comma)
+				db_printf(", ");
+			db_printf("ENTROPY");
+			comma = 1;
+		}
+		if (ih->ih_flags & IH_DEAD) {
+			if (comma)
+				db_printf(", ");
+			db_printf("DEAD");
+			comma = 1;
+		}
+		if (ih->ih_flags & IH_MPSAFE) {
+			if (comma)
+				db_printf(", ");
+			db_printf("MPSAFE");
+			comma = 1;
+		}
+		if (ih->ih_need) {
+			if (comma)
+				db_printf(", ");
+			db_printf("NEED");
+		}
+		db_printf("}");
+	}
+	db_printf("\n");
+}
+
+/*
+ * Dump details about a event.
+ */
+void
+db_dump_intr_event(struct intr_event *ie, int handlers)
+{
+	struct intr_handler *ih;
+	struct intr_thread *it;
+	int comma;
+
+	db_printf("%s ", ie->ie_fullname);
+	it = ie->ie_thread;
+	if (it != NULL)
+		db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
+	else
+		db_printf("(no thread)");
+	if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 ||
+	    (it != NULL && it->it_need)) {
+		db_printf(" {");
+		comma = 0;
+		if (ie->ie_flags & IE_SOFT) {
+			db_printf("SOFT");
+			comma = 1;
+		}
+		if (ie->ie_flags & IE_ENTROPY) {
+			if (comma)
+				db_printf(", ");
+			db_printf("ENTROPY");
+			comma = 1;
+		}
+		if (ie->ie_flags & IE_ADDING_THREAD) {
+			if (comma)
+				db_printf(", ");
+			db_printf("ADDING_THREAD");
+			comma = 1;
+		}
+		if (it != NULL && it->it_need) {
+			if (comma)
+				db_printf(", ");
+			db_printf("NEED");
+		}
+		db_printf("}");
+	}
+	db_printf("\n");
+
+	if (handlers)
+		TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
+		    db_dump_intrhand(ih);
+}
+
+/*
+ * Dump data about interrupt handlers
+ */
+DB_SHOW_COMMAND(intr, db_show_intr)
+{
+	struct intr_event *ie;
+	int all, verbose;
+
+	verbose = index(modif, 'v') != NULL;
+	all = index(modif, 'a') != NULL;
+	TAILQ_FOREACH(ie, &event_list, ie_list) {
+		if (!all && TAILQ_EMPTY(&ie->ie_handlers))
+			continue;
+		db_dump_intr_event(ie, verbose);
+		if (db_pager_quit)
+			break;
+	}
+}
+#endif /* DDB */
+
+/*
+ * Start standard software interrupt threads
+ */
+static void
+start_softintr(void *dummy)
+{
+
+	if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih))
+		panic("died while creating vm swi ithread");
+}
+SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
+    NULL);
+
+/*
+ * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
+ * The data for this machine dependent, and the declarations are in machine
+ * dependent code.  The layout of intrnames and intrcnt however is machine
+ * independent.
+ *
+ * We do not know the length of intrcnt and intrnames at compile time, so
+ * calculate things at run time.
+ */
+static int
+sysctl_intrnames(SYSCTL_HANDLER_ARGS)
+{
+	return (sysctl_handle_opaque(oidp, intrnames, eintrnames - intrnames,
+	   req));
+}
+
+SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
+    NULL, 0, sysctl_intrnames, "", "Interrupt Names");
+
+static int
+sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
+{
+	return (sysctl_handle_opaque(oidp, intrcnt,
+	    (char *)eintrcnt - (char *)intrcnt, req));
+}
+
+SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
+    NULL, 0, sysctl_intrcnt, "", "Interrupt Counts");
+
+#ifdef DDB
+/*
+ * DDB command to dump the interrupt statistics.
+ */
+DB_SHOW_COMMAND(intrcnt, db_show_intrcnt)
+{
+	u_long *i;
+	char *cp;
+
+	cp = intrnames;
+	for (i = intrcnt; i != eintrcnt && !db_pager_quit; i++) {
+		if (*cp == '\0')
+			break;
+		if (*i != 0)
+			db_printf("%s\t%lu\n", cp, *i);
+		cp += strlen(cp) + 1;
+	}
+}
+#endif
+#endif /* __rtems__ */