diff options
Diffstat (limited to 'sys/kern/kern_intr.c')
| -rw-r--r-- | sys/kern/kern_intr.c | 1565 |
1 files changed, 1565 insertions, 0 deletions
diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c new file mode 100644 index 0000000..8539c6e --- /dev/null +++ b/sys/kern/kern_intr.c @@ -0,0 +1,1565 @@ +/*- + * 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; +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 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_name, ie->ie_fullname, sizeof(td->td_name)); + 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; + 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_create(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); +} + +#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, 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); +} + +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 + +/* + * 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, 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, 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, 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, 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 |
