/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 1997, Stefan Esser * 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 #include "opt_ddb.h" #include "opt_hwpmc_hooks.h" #include "opt_kstack_usage_prof.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #include #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. */ int it_waiting; /* Waiting in the runq. */ }; /* Interrupt thread flags kept in it_flags */ #define IT_DEAD 0x000001 /* Thread is waiting to exit. */ #define IT_WAIT 0x000002 /* Thread is waiting for completion. */ struct intr_entropy { struct thread *td; uintptr_t event; }; struct intr_event *clk_intr_event; struct proc *intrproc; static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads"); static int intr_storm_threshold = 0; SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RWTUN, &intr_storm_threshold, 0, "Number of consecutive interrupts before storm protection is enabled"); static int intr_epoch_batch = 1000; SYSCTL_INT(_hw, OID_AUTO, intr_epoch_batch, CTLFLAG_RWTUN, &intr_epoch_batch, 0, "Maximum interrupt handler executions without re-entering epoch(9)"); #ifdef HWPMC_HOOKS static int intr_hwpmc_waiting_report_threshold = 1; SYSCTL_INT(_hw, OID_AUTO, intr_hwpmc_waiting_report_threshold, CTLFLAG_RWTUN, &intr_hwpmc_waiting_report_threshold, 1, "Threshold for reporting number of events in a workq"); #define PMC_HOOK_INSTALLED_ANY() __predict_false(pmc_hook != NULL) #endif 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); static int intr_event_schedule_thread(struct intr_event *ie, struct trapframe *frame); static struct intr_thread *ithread_create(const char *name); static void ithread_destroy(struct intr_thread *ithread); static void ithread_execute_handlers(struct proc *p, struct intr_event *ie); static void ithread_loop(void *); static void ithread_update(struct intr_thread *ithd); static void start_softintr(void *); #ifdef HWPMC_HOOKS #include PMC_SOFT_DEFINE( , , intr, all); PMC_SOFT_DEFINE( , , intr, ithread); PMC_SOFT_DEFINE( , , intr, filter); PMC_SOFT_DEFINE( , , intr, stray); PMC_SOFT_DEFINE( , , intr, schedule); PMC_SOFT_DEFINE( , , intr, waiting); #define PMC_SOFT_CALL_INTR_HLPR(event, frame) \ do { \ if (frame != NULL) \ PMC_SOFT_CALL_TF( , , intr, event, frame); \ else \ PMC_SOFT_CALL( , , intr, event); \ } while (0) #endif /* 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_TTY; break; case INTR_TYPE_BIO: pri = PI_DISK; break; case INTR_TYPE_NET: pri = PI_NET; break; case INTR_TYPE_CAM: pri = PI_DISK; break; case INTR_TYPE_AV: 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; mtx_assert(&ie->ie_lock, MA_OWNED); /* Determine the overall priority of this event. */ if (CK_SLIST_EMPTY(&ie->ie_handlers)) pri = PRI_MAX_ITHD; else pri = CK_SLIST_FIRST(&ie->ie_handlers)->ih_pri; /* Update name and priority. */ strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name)); #ifdef KTR sched_clear_tdname(td); #endif thread_lock(td); sched_ithread_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, flags; /* 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)); flags = 0; missed = 0; space = 1; /* Run through all the handlers updating values. */ CK_SLIST_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++; flags |= ih->ih_flags; } ie->ie_hflags = flags; /* * If there is only one handler and its name is too long, just copy in * as much of the end of the name (includes the unit number) as will * fit. Otherwise, we have multiple handlers and not all of the names * will fit. 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 *. */ if (missed == 1 && space == 1) { ih = CK_SLIST_FIRST(&ie->ie_handlers); missed = strlen(ie->ie_fullname) + strlen(ih->ih_name) + 2 - sizeof(ie->ie_fullname); strcat(ie->ie_fullname, (missed == 0) ? " " : "-"); strcat(ie->ie_fullname, &ih->ih_name[missed]); missed = 0; } 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); } int intr_event_create(struct intr_event **event, void *source, int flags, u_int irq, void (*pre_ithread)(void *), void (*post_ithread)(void *), void (*post_filter)(void *), int (*assign_cpu)(void *, int), 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; CK_SLIST_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. Using a cpu id of NOCPU unbinds * the interrupt event. */ static int _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread) { 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. */ if (bindithread) { mtx_lock(&ie->ie_lock); if (ie->ie_thread != NULL) { id = ie->ie_thread->it_thread->td_tid; mtx_unlock(&ie->ie_lock); error = cpuset_setithread(id, cpu); if (error) return (error); } else mtx_unlock(&ie->ie_lock); } if (bindirq) error = ie->ie_assign_cpu(ie->ie_source, cpu); if (error) { if (bindithread) { mtx_lock(&ie->ie_lock); if (ie->ie_thread != NULL) { cpu = ie->ie_cpu; id = ie->ie_thread->it_thread->td_tid; mtx_unlock(&ie->ie_lock); (void)cpuset_setithread(id, cpu); } else mtx_unlock(&ie->ie_lock); } return (error); } if (bindirq) { mtx_lock(&ie->ie_lock); ie->ie_cpu = cpu; mtx_unlock(&ie->ie_lock); } return (error); } /* * Bind an interrupt event to the specified CPU. For supported platforms, any * associated ithreads as well as the primary interrupt context will be bound * to the specificed CPU. */ int intr_event_bind(struct intr_event *ie, int cpu) { return (_intr_event_bind(ie, cpu, true, true)); } /* * Bind an interrupt event to the specified CPU, but do not bind associated * ithreads. */ int intr_event_bind_irqonly(struct intr_event *ie, int cpu) { return (_intr_event_bind(ie, cpu, true, false)); } /* * Bind an interrupt event's ithread to the specified CPU. */ int intr_event_bind_ithread(struct intr_event *ie, int cpu) { return (_intr_event_bind(ie, cpu, false, true)); } /* * Bind an interrupt event's ithread to the specified cpuset. */ int intr_event_bind_ithread_cpuset(struct intr_event *ie, cpuset_t *cs) { lwpid_t id; mtx_lock(&ie->ie_lock); if (ie->ie_thread != NULL) { id = ie->ie_thread->it_thread->td_tid; mtx_unlock(&ie->ie_lock); return (cpuset_setthread(id, cs)); } else { mtx_unlock(&ie->ie_lock); } return (ENODEV); } 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 && CK_SLIST_FIRST(&ie->ie_handlers) != NULL) break; mtx_unlock(&event_lock); return (ie); } int intr_setaffinity(int irq, int mode, const void *m) { struct intr_event *ie; const cpuset_t *mask; int cpu, 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 = n; } } ie = intr_lookup(irq); if (ie == NULL) return (ESRCH); switch (mode) { case CPU_WHICH_IRQ: return (intr_event_bind(ie, cpu)); case CPU_WHICH_INTRHANDLER: return (intr_event_bind_irqonly(ie, cpu)); case CPU_WHICH_ITHREAD: return (intr_event_bind_ithread(ie, cpu)); default: return (EINVAL); } } int intr_getaffinity(int irq, int mode, void *m) { struct intr_event *ie; struct thread *td; struct proc *p; cpuset_t *mask; lwpid_t id; int error; mask = m; ie = intr_lookup(irq); if (ie == NULL) return (ESRCH); error = 0; CPU_ZERO(mask); switch (mode) { case CPU_WHICH_IRQ: case CPU_WHICH_INTRHANDLER: 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); break; case CPU_WHICH_ITHREAD: mtx_lock(&ie->ie_lock); if (ie->ie_thread == NULL) { mtx_unlock(&ie->ie_lock); CPU_COPY(cpuset_root, mask); } else { id = ie->ie_thread->it_thread->td_tid; mtx_unlock(&ie->ie_lock); error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL); if (error != 0) return (error); CPU_COPY(&td->td_cpuset->cs_mask, mask); PROC_UNLOCK(p); } default: return (EINVAL); } return (0); } int intr_event_destroy(struct intr_event *ie) { if (ie == NULL) return (EINVAL); mtx_lock(&event_lock); mtx_lock(&ie->ie_lock); if (!CK_SLIST_EMPTY(&ie->ie_handlers)) { mtx_unlock(&ie->ie_lock); mtx_unlock(&event_lock); return (EBUSY); } TAILQ_REMOVE(&event_list, ie, ie_list); mtx_unlock(&event_lock); if (ie->ie_thread != NULL) ithread_destroy(ie->ie_thread); mtx_unlock(&ie->ie_lock); mtx_destroy(&ie->ie_lock); free(ie, M_ITHREAD); return (0); } 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); } static void ithread_destroy(struct intr_thread *ithread) { struct intr_event *ie; struct thread *td; td = ithread->it_thread; ie = ithread->it_event; mtx_assert(&ie->ie_lock, MA_OWNED); CTR2(KTR_INTR, "%s: killing %s", __func__, ie->ie_name); thread_lock(td); ithread->it_flags |= IT_DEAD; if (TD_AWAITING_INTR(td)) { TD_CLR_IWAIT(td); sched_wakeup(td, SRQ_INTR); } else thread_unlock(td); while (ie->ie_thread != NULL) msleep(ithread, &ie->ie_lock, 0, "ithd_dth", 0); } 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_handler **prevptr; 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; if (flags & INTR_TYPE_NET) ih->ih_flags |= IH_NET; /* We can only have one exclusive handler in a event. */ mtx_lock(&ie->ie_lock); if (!CK_SLIST_EMPTY(&ie->ie_handlers)) { if ((flags & INTR_EXCL) || (CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) { mtx_unlock(&ie->ie_lock); free(ih, M_ITHREAD); return (EINVAL); } } /* 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); } } /* Add the new handler to the event in priority order. */ CK_SLIST_FOREACH_PREVPTR(temp_ih, prevptr, &ie->ie_handlers, ih_next) { if (temp_ih->ih_pri > ih->ih_pri) break; } CK_SLIST_INSERT_PREVPTR(prevptr, temp_ih, ih, ih_next); intr_event_update(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); } /* * 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 CK_SLIST_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 = strchr(ih->ih_name, ':'); if (start == NULL) start = strchr(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); } /* * If intr_event_handle() is running in the ISR context at the time of the call, * then wait for it to complete. */ static void intr_event_barrier(struct intr_event *ie) { int phase; mtx_assert(&ie->ie_lock, MA_OWNED); phase = ie->ie_phase; /* * Switch phase to direct future interrupts to the other active counter. * Make sure that any preceding stores are visible before the switch. */ KASSERT(ie->ie_active[!phase] == 0, ("idle phase has activity")); atomic_store_rel_int(&ie->ie_phase, !phase); /* * This code cooperates with wait-free iteration of ie_handlers * in intr_event_handle. * Make sure that the removal and the phase update are not reordered * with the active count check. * Note that no combination of acquire and release fences can provide * that guarantee as Store->Load sequences can always be reordered. */ atomic_thread_fence_seq_cst(); /* * Now wait on the inactive phase. * The acquire fence is needed so that all post-barrier accesses * are after the check. */ while (ie->ie_active[phase] > 0) cpu_spinwait(); atomic_thread_fence_acq(); } static void intr_handler_barrier(struct intr_handler *handler) { struct intr_event *ie; ie = handler->ih_event; mtx_assert(&ie->ie_lock, MA_OWNED); KASSERT((handler->ih_flags & IH_DEAD) == 0, ("update for a removed handler")); if (ie->ie_thread == NULL) { intr_event_barrier(ie); return; } if ((handler->ih_flags & IH_CHANGED) == 0) { handler->ih_flags |= IH_CHANGED; intr_event_schedule_thread(ie, NULL); } while ((handler->ih_flags & IH_CHANGED) != 0) msleep(handler, &ie->ie_lock, 0, "ih_barr", 0); } /* * Sleep until an ithread finishes executing an interrupt handler. * * XXX Doesn't currently handle interrupt filters or fast interrupt * handlers. This is intended for LinuxKPI drivers only. * Do not use in BSD code. */ void _intr_drain(int irq) { struct intr_event *ie; struct intr_thread *ithd; struct thread *td; ie = intr_lookup(irq); if (ie == NULL) return; if (ie->ie_thread == NULL) return; ithd = ie->ie_thread; td = ithd->it_thread; /* * We set the flag and wait for it to be cleared to avoid * long delays with potentially busy interrupt handlers * were we to only sample TD_AWAITING_INTR() every tick. */ thread_lock(td); if (!TD_AWAITING_INTR(td)) { ithd->it_flags |= IT_WAIT; while (ithd->it_flags & IT_WAIT) { thread_unlock(td); pause("idrain", 1); thread_lock(td); } } thread_unlock(td); return; } int intr_event_remove_handler(void *cookie) { struct intr_handler *handler = (struct intr_handler *)cookie; struct intr_event *ie; struct intr_handler *ih; struct intr_handler **prevptr; 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); CK_SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) { if (ih == handler) break; } if (ih == NULL) { panic("interrupt handler \"%s\" not found in " "interrupt event \"%s\"", handler->ih_name, ie->ie_name); } if (ie->ie_thread == NULL) { /* * If there is no ithread, then directly remove the handler. * Note that intr_event_handle() iterates ie_handlers in a * lock-less fashion, so care needs to be taken to keep * ie_handlers consistent and to free the removed handler only * when ie_handlers is quiescent. */ CK_SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next); intr_event_barrier(ie); } else { /* * Let the interrupt thread do the job. The interrupt source is * disabled when the interrupt thread is running, so it does not * have to worry about interaction with intr_event_handle(). */ KASSERT((handler->ih_flags & IH_DEAD) == 0, ("duplicate handle remove")); handler->ih_flags |= IH_DEAD; intr_event_schedule_thread(ie, NULL); while (handler->ih_flags & IH_DEAD) msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0); } intr_event_update(ie); mtx_unlock(&ie->ie_lock); free(handler, M_ITHREAD); return (0); } int intr_event_suspend_handler(void *cookie) { struct intr_handler *handler = (struct intr_handler *)cookie; struct intr_event *ie; 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); handler->ih_flags |= IH_SUSP; intr_handler_barrier(handler); mtx_unlock(&ie->ie_lock); return (0); } int intr_event_resume_handler(void *cookie) { struct intr_handler *handler = (struct intr_handler *)cookie; struct intr_event *ie; if (handler == NULL) return (EINVAL); ie = handler->ih_event; KASSERT(ie != NULL, ("interrupt handler \"%s\" has a NULL interrupt event", handler->ih_name)); /* * intr_handler_barrier() acts not only as a barrier, * it also allows to check for any pending interrupts. */ mtx_lock(&ie->ie_lock); handler->ih_flags &= ~IH_SUSP; intr_handler_barrier(handler); mtx_unlock(&ie->ie_lock); return (0); } static int intr_event_schedule_thread(struct intr_event *ie, struct trapframe *frame) { struct intr_entropy entropy; struct intr_thread *it; struct thread *td; struct thread *ctd; /* * If no ithread or no handlers, then we have a stray interrupt. */ if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers) || ie->ie_thread == NULL) return (EINVAL); ctd = curthread; it = ie->ie_thread; td = it->it_thread; /* * If any of the handlers for this ithread claim to be good * sources of entropy, then gather some. */ if (ie->ie_hflags & IH_ENTROPY) { entropy.event = (uintptr_t)ie; entropy.td = ctd; random_harvest_queue(&entropy, sizeof(entropy), RANDOM_INTERRUPT); } KASSERT(td->td_proc != 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. * * Use store_rel to arrange that the store to ih_need in * swi_sched() is before the store to it_need and prepare for * transfer of this order to loads in the ithread. */ atomic_store_rel_int(&it->it_need, 1); thread_lock(td); if (TD_AWAITING_INTR(td)) { #ifdef HWPMC_HOOKS it->it_waiting = 0; if (PMC_HOOK_INSTALLED_ANY()) PMC_SOFT_CALL_INTR_HLPR(schedule, frame); #endif CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, td->td_proc->p_pid, td->td_name); TD_CLR_IWAIT(td); sched_wakeup(td, SRQ_INTR); } else { #ifdef HWPMC_HOOKS it->it_waiting++; if (PMC_HOOK_INSTALLED_ANY() && (it->it_waiting >= intr_hwpmc_waiting_report_threshold)) PMC_SOFT_CALL_INTR_HLPR(waiting, frame); #endif CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d", __func__, td->td_proc->p_pid, td->td_name, it->it_need, TD_GET_STATE(td)); thread_unlock(td); } return (0); } /* * 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, int 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 = 0; 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; } if (handler != NULL) { error = intr_event_add_handler(ie, name, NULL, handler, arg, PI_SWI(pri), flags, cookiep); } return (error); } /* * 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; struct intr_entropy entropy; int error __unused; CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name, ih->ih_need); if ((flags & SWI_FROMNMI) == 0) { entropy.event = (uintptr_t)ih; entropy.td = curthread; random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI); } /* * 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. */ ih->ih_need = 1; if (flags & SWI_DELAY) return; if (flags & SWI_FROMNMI) { #if defined(SMP) && (defined(__i386__) || defined(__amd64__)) KASSERT(ie == clk_intr_event, ("SWI_FROMNMI used not with clk_intr_event")); ipi_self_from_nmi(IPI_SWI); #endif } else { VM_CNT_INC(v_soft); error = intr_event_schedule_thread(ie, NULL); 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)); } static void intr_event_execute_handlers(struct proc *p, struct intr_event *ie) { struct intr_handler *ih, *ihn, *ihp; ihp = NULL; CK_SLIST_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); if (ihp == NULL) CK_SLIST_REMOVE_HEAD(&ie->ie_handlers, ih_next); else CK_SLIST_REMOVE_AFTER(ihp, ih_next); ih->ih_flags &= ~IH_DEAD; wakeup(ih); mtx_unlock(&ie->ie_lock); continue; } /* * Now that we know that the current element won't be removed * update the previous element. */ ihp = ih; if ((ih->ih_flags & IH_CHANGED) != 0) { mtx_lock(&ie->ie_lock); ih->ih_flags &= ~IH_CHANGED; wakeup(ih); mtx_unlock(&ie->ie_lock); } /* Skip filter only handlers */ if (ih->ih_handler == NULL) continue; /* Skip suspended handlers */ if ((ih->ih_flags & IH_SUSP) != 0) continue; /* * For software interrupt threads, we only execute * handlers that have their need flag set. Hardware * interrupt threads always invoke all of their handlers. * * ih_need can only be 0 or 1. Failed cmpset below * means that there is no request to execute handlers, * so a retry of the cmpset is not needed. */ if ((ie->ie_flags & IE_SOFT) != 0 && atomic_cmpset_int(&ih->ih_need, 1, 0) == 0) continue; /* 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 (__predict_false(intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold && (ie->ie_flags & IE_SOFT) == 0)) { /* 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); } /* * This is the main code for interrupt threads. */ static void ithread_loop(void *arg) { struct epoch_tracker et; struct intr_thread *ithd; struct intr_event *ie; struct thread *td; struct proc *p; int epoch_count; bool needs_epoch; 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 (__predict_false((ithd->it_flags & IT_DEAD) != 0)) { CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__, p->p_pid, td->td_name); mtx_lock(&ie->ie_lock); ie->ie_thread = NULL; wakeup(ithd); mtx_unlock(&ie->ie_lock); 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. * * The load_acq part of the following cmpset ensures * that the load of ih_need in ithread_execute_handlers() * is ordered after the load of it_need here. */ needs_epoch = (atomic_load_int(&ie->ie_hflags) & IH_NET) != 0; if (needs_epoch) { epoch_count = 0; NET_EPOCH_ENTER(et); } while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) { ithread_execute_handlers(p, ie); if (needs_epoch && ++epoch_count >= intr_epoch_batch) { NET_EPOCH_EXIT(et); epoch_count = 0; NET_EPOCH_ENTER(et); } } if (needs_epoch) NET_EPOCH_EXIT(et); 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 (atomic_load_acq_int(&ithd->it_need) == 0 && (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) { TD_SET_IWAIT(td); ie->ie_count = 0; mi_switch(SW_VOL | SWT_IWAIT); } else if ((ithd->it_flags & IT_WAIT) != 0) { ithd->it_flags &= ~IT_WAIT; thread_unlock(td); wakeup(ithd); } else thread_unlock(td); } } /* * Main interrupt handling body. * * Input: * o ie: the event connected to this interrupt. -------------------------------------------------------------------------------- * o frame: the current trap frame. If the client interrupt * handler needs this frame, they should get it * via curthread->td_intr_frame. * * 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 trapframe *oldframe; struct thread *td; int phase; int ret; bool filter, thread; td = curthread; #ifdef KSTACK_USAGE_PROF intr_prof_stack_use(td, frame); #endif /* An interrupt with no event or handlers is a stray interrupt. */ if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers)) return (EINVAL); /* * Execute fast interrupt handlers directly. */ td->td_intr_nesting_level++; filter = false; thread = false; ret = 0; critical_enter(); oldframe = td->td_intr_frame; td->td_intr_frame = frame; phase = ie->ie_phase; atomic_add_int(&ie->ie_active[phase], 1); /* * This fence is required to ensure that no later loads are * re-ordered before the ie_active store. */ atomic_thread_fence_seq_cst(); CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) { if ((ih->ih_flags & IH_SUSP) != 0) continue; if ((ie->ie_flags & IE_SOFT) != 0 && ih->ih_need == 0) continue; if (ih->ih_filter == NULL) { thread = true; continue; } CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__, ih->ih_filter, ih->ih_argument, ih->ih_name); ret = ih->ih_filter(ih->ih_argument); #ifdef HWPMC_HOOKS PMC_SOFT_CALL_TF( , , intr, all, frame); #endif 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)); filter = filter || ret == FILTER_HANDLED; #ifdef HWPMC_HOOKS if (ret & FILTER_SCHEDULE_THREAD) PMC_SOFT_CALL_TF( , , intr, ithread, frame); else if (ret & FILTER_HANDLED) PMC_SOFT_CALL_TF( , , intr, filter, frame); else if (ret == FILTER_STRAY) PMC_SOFT_CALL_TF( , , intr, stray, frame); #endif /* * 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 = true; } } atomic_add_rel_int(&ie->ie_active[phase], -1); td->td_intr_frame = oldframe; 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) { int error __unused; error = intr_event_schedule_thread(ie, frame); KASSERT(error == 0, ("bad stray interrupt")); } critical_exit(); td->td_intr_nesting_level--; #ifdef notyet /* The interrupt is not aknowledged by any filter and has no ithread. */ if (!thread && !filter) return (EINVAL); #endif return (0); } #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_INTR: db_printf("INTR"); break; default: if (ih->ih_pri >= PI_SOFT) db_printf("SWI "); else db_printf("%4u", ih->ih_pri); break; } db_printf(" "); if (ih->ih_filter != NULL) { db_printf("[F]"); db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC); } if (ih->ih_handler != NULL) { if (ih->ih_filter != NULL) db_printf(","); db_printf("[H]"); 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_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_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) CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) db_dump_intrhand(ih); } /* * Dump data about interrupt handlers */ DB_SHOW_COMMAND_FLAGS(intr, db_show_intr, DB_CMD_MEMSAFE) { struct intr_event *ie; int all, verbose; verbose = strchr(modif, 'v') != NULL; all = strchr(modif, 'a') != NULL; TAILQ_FOREACH(ie, &event_list, ie_list) { if (!all && CK_SLIST_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(&clk_intr_event, "clk", NULL, NULL, SWI_CLOCK, INTR_MPSAFE, NULL)) panic("died while creating clk 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, sintrnames, req)); } SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_intrnames, "", "Interrupt Names"); static int sysctl_intrcnt(SYSCTL_HANDLER_ARGS) { #ifdef SCTL_MASK32 uint32_t *intrcnt32; unsigned i; int error; if (req->flags & SCTL_MASK32) { if (!req->oldptr) return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req)); intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT); if (intrcnt32 == NULL) return (ENOMEM); for (i = 0; i < sintrcnt / sizeof (u_long); i++) intrcnt32[i] = intrcnt[i]; error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req); free(intrcnt32, M_TEMP); return (error); } #endif return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req)); } SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); #ifdef DDB /* * DDB command to dump the interrupt statistics. */ DB_SHOW_COMMAND_FLAGS(intrcnt, db_show_intrcnt, DB_CMD_MEMSAFE) { u_long *i; char *cp; u_int j; cp = intrnames; j = 0; for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit; i++, j++) { if (*cp == '\0') break; if (*i != 0) db_printf("%s\t%lu\n", cp, *i); cp += strlen(cp) + 1; } } #endif