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freebsd-skq/sys/kern/kern_intr.c
jeff 91d1501790 Commit 14/14 of sched_lock decomposition. 
- Use thread_lock() rather than sched_lock for per-thread scheduling
   sychronization.
 - Use the per-process spinlock rather than the sched_lock for per-process
   scheduling synchronization.

Tested by:      kris, current@
Tested on:      i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
2007-06-05 00:00:57 +00:00

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39 KiB
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/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/rtprio.h>
#include <sys/systm.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/ktr.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/random.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <sys/vmmeter.h>
#include <machine/atomic.h>
#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/stdarg.h>
#ifdef DDB
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
#endif
/*
* 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 *softclock_ih;
void *vm_ih;
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 void intr_event_update(struct intr_event *ie);
#ifdef INTR_FILTER
static struct intr_thread *ithread_create(const char *name,
struct intr_handler *ih);
#else
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 *);
static void ithread_update(struct intr_thread *ithd);
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_proc->p_comm, ie->ie_fullname,
sizeof(td->td_proc->p_comm));
thread_lock(td);
sched_prio(td, pri);
thread_unlock(td);
}
/*
* 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 INTR_FILTER
int
intr_event_create(struct intr_event **event, void *source, int flags,
void (*enable)(void *), 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_enable = enable;
ie->ie_flags = flags;
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_pool_lock(mtxpool_sleep, &event_list);
TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
mtx_pool_unlock(mtxpool_sleep, &event_list);
if (event != NULL)
*event = ie;
CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
return (0);
}
#else
int
intr_event_create(struct intr_event **event, void *source, int flags,
void (*enable)(void *), void (*eoi)(void *), void (*disab)(void *),
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_enable = enable;
ie->ie_eoi = eoi;
ie->ie_disab = disab;
ie->ie_flags = flags;
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_pool_lock(mtxpool_sleep, &event_list);
TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
mtx_pool_unlock(mtxpool_sleep, &event_list);
if (event != NULL)
*event = ie;
CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
return (0);
}
#endif
int
intr_event_destroy(struct intr_event *ie)
{
mtx_lock(&ie->ie_lock);
if (!TAILQ_EMPTY(&ie->ie_handlers)) {
mtx_unlock(&ie->ie_lock);
return (EBUSY);
}
mtx_pool_lock(mtxpool_sleep, &event_list);
TAILQ_REMOVE(&event_list, ie, ie_list);
mtx_pool_unlock(mtxpool_sleep, &event_list);
#ifndef notyet
if (ie->ie_thread != NULL) {
ithread_destroy(ie->ie_thread);
ie->ie_thread = NULL;
}
#endif
mtx_unlock(&ie->ie_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;
struct proc *p;
int error;
ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
error = kthread_create(ithread_loop, ithd, &p, RFSTOPPED | RFHIGHPID,
0, "%s", name);
if (error)
panic("kthread_create() failed with %d", error);
td = FIRST_THREAD_IN_PROC(p); /* XXXKSE */
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;
struct proc *p;
int error;
ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
error = kthread_create(ithread_loop, ih, &p, RFSTOPPED | RFHIGHPID,
0, "%s", name);
if (error)
panic("kthread_create() failed with %d", error);
td = FIRST_THREAD_IN_PROC(p); /* XXXKSE */
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);
}
#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;
ih->ih_name = 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;
ih->ih_name = 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
/*
* 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);
}
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, p->p_comm);
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,
p->p_comm);
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, p->p_comm, 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);
}
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, p->p_comm);
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,
p->p_comm);
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, p->p_comm, it->it_need, td->td_state);
}
thread_unlock(td);
return (0);
}
#endif
/*
* 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 {
#ifdef INTR_FILTER
error = intr_event_create(&ie, NULL, IE_SOFT,
NULL, NULL, NULL, "swi%d:", pri);
#else
error = intr_event_create(&ie, NULL, IE_SOFT,
NULL, "swi%d:", pri);
#endif
if (error)
return (error);
if (eventp != NULL)
*eventp = ie;
}
return (intr_event_add_handler(ie, name, NULL, handler, arg,
(pri * RQ_PPQ) + PI_SOFT, flags, cookiep));
/* XXKSE.. think of a better way to get separate queues */
}
/*
* 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
static void
ithread_execute_handlers(struct proc *p, struct intr_event *ie)
{
struct intr_handler *ih, *ihn;
/* Interrupt handlers should not sleep. */
if (!(ie->ie_flags & IE_SOFT))
THREAD_NO_SLEEPING();
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);
}
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_enable != NULL)
ie->ie_enable(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, p->p_comm);
free(ithd, M_ITHREAD);
kthread_exit(0);
}
/*
* 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, NULL);
}
thread_unlock(td);
}
}
#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, p->p_comm);
free(ithd, M_ITHREAD);
kthread_exit(0);
}
/*
* 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, 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.
*/
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;
}
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 the interrupt was fully served, send it an EOI but leave
* it unmasked. Otherwise, mask the source as well as sending
* it an EOI.
*/
if (thread & FILTER_HANDLED) {
if (ie->ie_eoi != NULL)
ie->ie_eoi(ie->ie_source);
} else {
if (ie->ie_disab != NULL)
ie->ie_disab(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)
{
struct proc *p;
if (swi_add(&clk_intr_event, "clock", softclock, NULL, SWI_CLOCK,
INTR_MPSAFE, &softclock_ih) ||
swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih))
panic("died while creating standard software ithreads");
p = clk_intr_event->ie_thread->it_thread->td_proc;
PROC_LOCK(p);
p->p_flag |= P_NOLOAD;
PROC_UNLOCK(p);
}
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
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