/* * Copyright (C) 2001 Julian Elischer . * 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(s), this list of conditions and the following disclaimer as * the first lines of this file unmodified other than the possible * addition of one or more copyright notices. * 2. Redistributions in binary form must reproduce the above copyright * notice(s), 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 COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * KSEGRP related storage. */ static uma_zone_t upcall_zone; /* DEBUG ONLY */ extern int virtual_cpu; extern int thread_debug; extern int max_threads_per_proc; extern int max_groups_per_proc; extern int max_threads_hits; extern struct mtx kse_zombie_lock; #define RANGEOF(type, start, end) (offsetof(type, end) - offsetof(type, start)) TAILQ_HEAD(, kse_upcall) zombie_upcalls = TAILQ_HEAD_INITIALIZER(zombie_upcalls); static int thread_update_usr_ticks(struct thread *td); static void thread_alloc_spare(struct thread *td); struct kse_upcall * upcall_alloc(void) { struct kse_upcall *ku; ku = uma_zalloc(upcall_zone, M_WAITOK); bzero(ku, sizeof(*ku)); return (ku); } void upcall_free(struct kse_upcall *ku) { uma_zfree(upcall_zone, ku); } void upcall_link(struct kse_upcall *ku, struct ksegrp *kg) { mtx_assert(&sched_lock, MA_OWNED); TAILQ_INSERT_TAIL(&kg->kg_upcalls, ku, ku_link); ku->ku_ksegrp = kg; kg->kg_numupcalls++; } void upcall_unlink(struct kse_upcall *ku) { struct ksegrp *kg = ku->ku_ksegrp; mtx_assert(&sched_lock, MA_OWNED); KASSERT(ku->ku_owner == NULL, ("%s: have owner", __func__)); TAILQ_REMOVE(&kg->kg_upcalls, ku, ku_link); kg->kg_numupcalls--; upcall_stash(ku); } void upcall_remove(struct thread *td) { if (td->td_upcall) { td->td_upcall->ku_owner = NULL; upcall_unlink(td->td_upcall); td->td_upcall = 0; } } #ifndef _SYS_SYSPROTO_H_ struct kse_switchin_args { struct kse_thr_mailbox *tmbx; int flags; }; #endif int kse_switchin(struct thread *td, struct kse_switchin_args *uap) { struct kse_thr_mailbox tmbx; struct kse_upcall *ku; int error; if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td)) return (EINVAL); error = (uap->tmbx == NULL) ? EINVAL : 0; if (!error) error = copyin(uap->tmbx, &tmbx, sizeof(tmbx)); if (!error && (uap->flags & KSE_SWITCHIN_SETTMBX)) error = (suword(&ku->ku_mailbox->km_curthread, (long)uap->tmbx) != 0 ? EINVAL : 0); if (!error) error = set_mcontext(td, &tmbx.tm_context.uc_mcontext); if (!error) { suword32(&uap->tmbx->tm_lwp, td->td_tid); if (uap->flags & KSE_SWITCHIN_SETTMBX) { td->td_mailbox = uap->tmbx; td->td_pflags |= TDP_CAN_UNBIND; } if (td->td_proc->p_flag & P_TRACED) { if (tmbx.tm_dflags & TMDF_SSTEP) ptrace_single_step(td); else ptrace_clear_single_step(td); if (tmbx.tm_dflags & TMDF_SUSPEND) { mtx_lock_spin(&sched_lock); /* fuword can block, check again */ if (td->td_upcall) ku->ku_flags |= KUF_DOUPCALL; mtx_unlock_spin(&sched_lock); } } } return ((error == 0) ? EJUSTRETURN : error); } /* struct kse_thr_interrupt_args { struct kse_thr_mailbox * tmbx; int cmd; long data; }; */ int kse_thr_interrupt(struct thread *td, struct kse_thr_interrupt_args *uap) { struct proc *p; struct thread *td2; struct kse_upcall *ku; struct kse_thr_mailbox *tmbx; uint32_t flags; p = td->td_proc; if (!(p->p_flag & P_SA)) return (EINVAL); switch (uap->cmd) { case KSE_INTR_SENDSIG: if (uap->data < 0 || uap->data > _SIG_MAXSIG) return (EINVAL); case KSE_INTR_INTERRUPT: case KSE_INTR_RESTART: PROC_LOCK(p); mtx_lock_spin(&sched_lock); FOREACH_THREAD_IN_PROC(p, td2) { if (td2->td_mailbox == uap->tmbx) break; } if (td2 == NULL) { mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); return (ESRCH); } if (uap->cmd == KSE_INTR_SENDSIG) { if (uap->data > 0) { td2->td_flags &= ~TDF_INTERRUPT; mtx_unlock_spin(&sched_lock); tdsignal(td2, (int)uap->data, SIGTARGET_TD); } else { mtx_unlock_spin(&sched_lock); } } else { td2->td_flags |= TDF_INTERRUPT | TDF_ASTPENDING; if (TD_CAN_UNBIND(td2)) td2->td_upcall->ku_flags |= KUF_DOUPCALL; if (uap->cmd == KSE_INTR_INTERRUPT) td2->td_intrval = EINTR; else td2->td_intrval = ERESTART; if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR)) sleepq_abort(td2); mtx_unlock_spin(&sched_lock); } PROC_UNLOCK(p); break; case KSE_INTR_SIGEXIT: if (uap->data < 1 || uap->data > _SIG_MAXSIG) return (EINVAL); PROC_LOCK(p); sigexit(td, (int)uap->data); break; case KSE_INTR_DBSUSPEND: /* this sub-function is only for bound thread */ if (td->td_pflags & TDP_SA) return (EINVAL); ku = td->td_upcall; tmbx = (void *)fuword((void *)&ku->ku_mailbox->km_curthread); if (tmbx == NULL || tmbx == (void *)-1) return (EINVAL); flags = 0; while ((p->p_flag & P_TRACED) && !(p->p_flag & P_SINGLE_EXIT)) { flags = fuword32(&tmbx->tm_dflags); if (!(flags & TMDF_SUSPEND)) break; PROC_LOCK(p); mtx_lock_spin(&sched_lock); thread_stopped(p); thread_suspend_one(td); PROC_UNLOCK(p); mi_switch(SW_VOL, NULL); mtx_unlock_spin(&sched_lock); } return (0); default: return (EINVAL); } return (0); } /* struct kse_exit_args { register_t dummy; }; */ int kse_exit(struct thread *td, struct kse_exit_args *uap) { struct proc *p; struct ksegrp *kg; struct kse_upcall *ku, *ku2; int error, count; p = td->td_proc; /* * Ensure that this is only called from the UTS */ if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td)) return (EINVAL); kg = td->td_ksegrp; count = 0; /* * Calculate the existing non-exiting upcalls in this ksegroup. * If we are the last upcall but there are still other threads, * then do not exit. We need the other threads to be able to * complete whatever they are doing. * XXX This relies on the userland knowing what to do if we return. * It may be a better choice to convert ourselves into a kse_release * ( or similar) and wait in the kernel to be needed. */ PROC_LOCK(p); mtx_lock_spin(&sched_lock); FOREACH_UPCALL_IN_GROUP(kg, ku2) { if (ku2->ku_flags & KUF_EXITING) count++; } if ((kg->kg_numupcalls - count) == 1 && (kg->kg_numthreads > 1)) { mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); return (EDEADLK); } ku->ku_flags |= KUF_EXITING; mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); /* * Mark the UTS mailbox as having been finished with. * If that fails then just go for a segfault. * XXX need to check it that can be deliverred without a mailbox. */ error = suword32(&ku->ku_mailbox->km_flags, ku->ku_mflags|KMF_DONE); if (!(td->td_pflags & TDP_SA)) if (suword32(&td->td_mailbox->tm_lwp, 0)) error = EFAULT; PROC_LOCK(p); if (error) psignal(p, SIGSEGV); mtx_lock_spin(&sched_lock); upcall_remove(td); if (p->p_numthreads != 1) { /* * If we are not the last thread, but we are the last * thread in this ksegrp, then by definition this is not * the last group and we need to clean it up as well. * thread_exit will clean up the kseg as needed. */ thread_stopped(p); thread_exit(); /* NOTREACHED */ } /* * This is the last thread. Just return to the user. * We know that there is only one ksegrp too, as any others * would have been discarded in previous calls to thread_exit(). * Effectively we have left threading mode.. * The only real thing left to do is ensure that the * scheduler sets out concurrency back to 1 as that may be a * resource leak otherwise. * This is an A[PB]I issue.. what SHOULD we do? * One possibility is to return to the user. It may not cope well. * The other possibility would be to let the process exit. */ p->p_flag &= ~(P_SA|P_HADTHREADS); sched_set_concurrency(td->td_ksegrp, 1); mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); #if 1 return (0); #else exit1(td, 0); #endif } /* * Either becomes an upcall or waits for an awakening event and * then becomes an upcall. Only error cases return. */ /* struct kse_release_args { struct timespec *timeout; }; */ int kse_release(struct thread *td, struct kse_release_args *uap) { struct proc *p; struct ksegrp *kg; struct kse_upcall *ku; struct timespec timeout; struct timeval tv; sigset_t sigset; int error; p = td->td_proc; kg = td->td_ksegrp; if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td)) return (EINVAL); if (uap->timeout != NULL) { if ((error = copyin(uap->timeout, &timeout, sizeof(timeout)))) return (error); TIMESPEC_TO_TIMEVAL(&tv, &timeout); } if (td->td_pflags & TDP_SA) td->td_pflags |= TDP_UPCALLING; else { ku->ku_mflags = fuword32(&ku->ku_mailbox->km_flags); if (ku->ku_mflags == -1) { PROC_LOCK(p); sigexit(td, SIGSEGV); } } PROC_LOCK(p); if (ku->ku_mflags & KMF_WAITSIGEVENT) { /* UTS wants to wait for signal event */ if (!(p->p_flag & P_SIGEVENT) && !(ku->ku_flags & KUF_DOUPCALL)) { td->td_kflags |= TDK_KSERELSIG; error = msleep(&p->p_siglist, &p->p_mtx, PPAUSE|PCATCH, "ksesigwait", (uap->timeout ? tvtohz(&tv) : 0)); td->td_kflags &= ~(TDK_KSERELSIG | TDK_WAKEUP); } p->p_flag &= ~P_SIGEVENT; sigset = p->p_siglist; PROC_UNLOCK(p); error = copyout(&sigset, &ku->ku_mailbox->km_sigscaught, sizeof(sigset)); } else { if ((ku->ku_flags & KUF_DOUPCALL) == 0 && ((ku->ku_mflags & KMF_NOCOMPLETED) || (kg->kg_completed == NULL))) { kg->kg_upsleeps++; td->td_kflags |= TDK_KSEREL; error = msleep(&kg->kg_completed, &p->p_mtx, PPAUSE|PCATCH, "kserel", (uap->timeout ? tvtohz(&tv) : 0)); td->td_kflags &= ~(TDK_KSEREL | TDK_WAKEUP); kg->kg_upsleeps--; } PROC_UNLOCK(p); } if (ku->ku_flags & KUF_DOUPCALL) { mtx_lock_spin(&sched_lock); ku->ku_flags &= ~KUF_DOUPCALL; mtx_unlock_spin(&sched_lock); } return (0); } /* struct kse_wakeup_args { struct kse_mailbox *mbx; }; */ int kse_wakeup(struct thread *td, struct kse_wakeup_args *uap) { struct proc *p; struct ksegrp *kg; struct kse_upcall *ku; struct thread *td2; p = td->td_proc; td2 = NULL; ku = NULL; /* KSE-enabled processes only, please. */ if (!(p->p_flag & P_SA)) return (EINVAL); PROC_LOCK(p); mtx_lock_spin(&sched_lock); if (uap->mbx) { FOREACH_KSEGRP_IN_PROC(p, kg) { FOREACH_UPCALL_IN_GROUP(kg, ku) { if (ku->ku_mailbox == uap->mbx) break; } if (ku) break; } } else { kg = td->td_ksegrp; if (kg->kg_upsleeps) { mtx_unlock_spin(&sched_lock); wakeup(&kg->kg_completed); PROC_UNLOCK(p); return (0); } ku = TAILQ_FIRST(&kg->kg_upcalls); } if (ku == NULL) { mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); return (ESRCH); } if ((td2 = ku->ku_owner) == NULL) { mtx_unlock_spin(&sched_lock); panic("%s: no owner", __func__); } else if (td2->td_kflags & (TDK_KSEREL | TDK_KSERELSIG)) { mtx_unlock_spin(&sched_lock); if (!(td2->td_kflags & TDK_WAKEUP)) { td2->td_kflags |= TDK_WAKEUP; if (td2->td_kflags & TDK_KSEREL) sleepq_remove(td2, &kg->kg_completed); else sleepq_remove(td2, &p->p_siglist); } } else { ku->ku_flags |= KUF_DOUPCALL; mtx_unlock_spin(&sched_lock); } PROC_UNLOCK(p); return (0); } /* * No new KSEG: first call: use current KSE, don't schedule an upcall * All other situations, do allocate max new KSEs and schedule an upcall. * * XXX should be changed so that 'first' behaviour lasts for as long * as you have not made a kse in this ksegrp. i.e. as long as we do not have * a mailbox.. */ /* struct kse_create_args { struct kse_mailbox *mbx; int newgroup; }; */ int kse_create(struct thread *td, struct kse_create_args *uap) { struct ksegrp *newkg; struct ksegrp *kg; struct proc *p; struct kse_mailbox mbx; struct kse_upcall *newku; int err, ncpus, sa = 0, first = 0; struct thread *newtd; p = td->td_proc; if ((err = copyin(uap->mbx, &mbx, sizeof(mbx)))) return (err); /* * Processes using the other threading model can't * suddenly start calling this one */ if ((p->p_flag & (P_SA|P_HADTHREADS)) == P_HADTHREADS) return (EINVAL); ncpus = mp_ncpus; if (virtual_cpu != 0) ncpus = virtual_cpu; /* * If the new UTS mailbox says that this * will be a BOUND lwp, then it had better * have its thread mailbox already there. * In addition, this ksegrp will be limited to * a concurrency of 1. There is more on this later. */ if (mbx.km_flags & KMF_BOUND) { if (mbx.km_curthread == NULL) return (EINVAL); ncpus = 1; } else { sa = TDP_SA; } PROC_LOCK(p); if (!(p->p_flag & P_SA)) { first = 1; p->p_flag |= P_SA|P_HADTHREADS; } PROC_UNLOCK(p); /* * Now pay attention! * If we are going to be bound, then we need to be either * a new group, or the first call ever. In either * case we will be creating (or be) the only thread in a group. * and the concurrency will be set to 1. * This is not quite right, as we may still make ourself * bound after making other ksegrps but it will do for now. * The library will only try do this much. */ if (!sa && !(uap->newgroup || first)) return (EINVAL); kg = td->td_ksegrp; if (uap->newgroup) { newkg = ksegrp_alloc(); bzero(&newkg->kg_startzero, RANGEOF(struct ksegrp, kg_startzero, kg_endzero)); bcopy(&kg->kg_startcopy, &newkg->kg_startcopy, RANGEOF(struct ksegrp, kg_startcopy, kg_endcopy)); PROC_LOCK(p); mtx_lock_spin(&sched_lock); if (p->p_numksegrps >= max_groups_per_proc) { mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); ksegrp_free(newkg); return (EPROCLIM); } ksegrp_link(newkg, p); sched_fork_ksegrp(td, newkg); mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); } else { /* * We want to make a thread in our own ksegrp. * If we are just the first call, either kind * is ok, but if not then either we must be * already an upcallable thread to make another, * or a bound thread to make one of those. * Once again, not quite right but good enough for now.. XXXKSE */ if (!first && ((td->td_pflags & TDP_SA) != sa)) return (EINVAL); newkg = kg; } /* * This test is a bit "indirect". * It might simplify things if we made a direct way of testing * if a ksegrp has been worked on before. * In the case of a bound request and the concurrency being set to * one, the concurrency will already be 1 so it's just inefficient * but not dangerous to call this again. XXX */ if (newkg->kg_numupcalls == 0) { /* * Initialize KSE group with the appropriate * concurrency. * * For a multiplexed group, create as as much concurrency * as the number of physical cpus. * This increases concurrency in the kernel even if the * userland is not MP safe and can only run on a single CPU. * In an ideal world, every physical cpu should execute a * thread. If there is enough concurrency, threads in the * kernel can be executed parallel on different cpus at * full speed without being restricted by the number of * upcalls the userland provides. * Adding more upcall structures only increases concurrency * in userland. * * For a bound thread group, because there is only one thread * in the group, we only set the concurrency for the group * to 1. A thread in this kind of group will never schedule * an upcall when blocked. This simulates pthread system * scope thread behaviour. */ sched_set_concurrency(newkg, ncpus); } /* * Even bound LWPs get a mailbox and an upcall to hold it. */ newku = upcall_alloc(); newku->ku_mailbox = uap->mbx; newku->ku_func = mbx.km_func; bcopy(&mbx.km_stack, &newku->ku_stack, sizeof(stack_t)); /* * For the first call this may not have been set. * Of course nor may it actually be needed. */ if (td->td_standin == NULL) thread_alloc_spare(td); /* * Creating upcalls more than number of physical cpu does * not help performance. */ PROC_LOCK(p); if (newkg->kg_numupcalls >= ncpus) { PROC_UNLOCK(p); upcall_free(newku); return (EPROCLIM); } /* * If we are the first time, and a normal thread, * then trnasfer all the signals back to the 'process'. * SA threading will make a special thread to handle them. */ if (first && sa) { SIGSETOR(p->p_siglist, td->td_siglist); SIGEMPTYSET(td->td_siglist); SIGFILLSET(td->td_sigmask); SIG_CANTMASK(td->td_sigmask); } /* * Make the new upcall available to the ksegrp,. * It may or may not use it, but its available. */ mtx_lock_spin(&sched_lock); PROC_UNLOCK(p); upcall_link(newku, newkg); if (mbx.km_quantum) newkg->kg_upquantum = max(1, mbx.km_quantum/tick); /* * Each upcall structure has an owner thread, find which * one owns it. */ if (uap->newgroup) { /* * Because the new ksegrp hasn't a thread, * create an initial upcall thread to own it. */ newtd = thread_schedule_upcall(td, newku); } else { /* * If the current thread hasn't an upcall structure, * just assign the upcall to it. * It'll just return. */ if (td->td_upcall == NULL) { newku->ku_owner = td; td->td_upcall = newku; newtd = td; } else { /* * Create a new upcall thread to own it. */ newtd = thread_schedule_upcall(td, newku); } } mtx_unlock_spin(&sched_lock); /* * Let the UTS instance know its LWPID. * It doesn't really care. But the debugger will. */ suword32(&newku->ku_mailbox->km_lwp, newtd->td_tid); /* * In the same manner, if the UTS has a current user thread, * then it is also running on this LWP so set it as well. * The library could do that of course.. but why not.. */ if (mbx.km_curthread) suword32(&mbx.km_curthread->tm_lwp, newtd->td_tid); if (sa) { newtd->td_pflags |= TDP_SA; } else { newtd->td_pflags &= ~TDP_SA; /* * Since a library will use the mailbox pointer to * identify even a bound thread, and the mailbox pointer * will never be allowed to change after this syscall * for a bound thread, set it here so the library can * find the thread after the syscall returns. */ newtd->td_mailbox = mbx.km_curthread; if (newtd != td) { /* * If we did create a new thread then * make sure it goes to the right place * when it starts up, and make sure that it runs * at full speed when it gets there. * thread_schedule_upcall() copies all cpu state * to the new thread, so we should clear single step * flag here. */ cpu_set_upcall_kse(newtd, newku); if (p->p_flag & P_TRACED) ptrace_clear_single_step(newtd); } } /* * If we are starting a new thread, kick it off. */ if (newtd != td) { mtx_lock_spin(&sched_lock); setrunqueue(newtd, SRQ_BORING); mtx_unlock_spin(&sched_lock); } return (0); } /* * Initialize global thread allocation resources. */ void kseinit(void) { upcall_zone = uma_zcreate("UPCALL", sizeof(struct kse_upcall), NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0); } /* * Stash an embarasingly extra upcall into the zombie upcall queue. */ void upcall_stash(struct kse_upcall *ku) { mtx_lock_spin(&kse_zombie_lock); TAILQ_INSERT_HEAD(&zombie_upcalls, ku, ku_link); mtx_unlock_spin(&kse_zombie_lock); } /* * Reap zombie kse resource. */ void kse_GC(void) { struct kse_upcall *ku_first, *ku_next; /* * Don't even bother to lock if none at this instant, * we really don't care about the next instant.. */ if (!TAILQ_EMPTY(&zombie_upcalls)) { mtx_lock_spin(&kse_zombie_lock); ku_first = TAILQ_FIRST(&zombie_upcalls); if (ku_first) TAILQ_INIT(&zombie_upcalls); mtx_unlock_spin(&kse_zombie_lock); while (ku_first) { ku_next = TAILQ_NEXT(ku_first, ku_link); upcall_free(ku_first); ku_first = ku_next; } } } /* * Store the thread context in the UTS's mailbox. * then add the mailbox at the head of a list we are building in user space. * The list is anchored in the ksegrp structure. */ int thread_export_context(struct thread *td, int willexit) { struct proc *p; struct ksegrp *kg; uintptr_t mbx; void *addr; int error = 0, sig; mcontext_t mc; p = td->td_proc; kg = td->td_ksegrp; /* * Post sync signal, or process SIGKILL and SIGSTOP. * For sync signal, it is only possible when the signal is not * caught by userland or process is being debugged. */ PROC_LOCK(p); if (td->td_flags & TDF_NEEDSIGCHK) { mtx_lock_spin(&sched_lock); td->td_flags &= ~TDF_NEEDSIGCHK; mtx_unlock_spin(&sched_lock); mtx_lock(&p->p_sigacts->ps_mtx); while ((sig = cursig(td)) != 0) postsig(sig); mtx_unlock(&p->p_sigacts->ps_mtx); } if (willexit) SIGFILLSET(td->td_sigmask); PROC_UNLOCK(p); /* Export the user/machine context. */ get_mcontext(td, &mc, 0); addr = (void *)(&td->td_mailbox->tm_context.uc_mcontext); error = copyout(&mc, addr, sizeof(mcontext_t)); if (error) goto bad; addr = (caddr_t)(&td->td_mailbox->tm_lwp); if (suword32(addr, 0)) { error = EFAULT; goto bad; } /* Get address in latest mbox of list pointer */ addr = (void *)(&td->td_mailbox->tm_next); /* * Put the saved address of the previous first * entry into this one */ for (;;) { mbx = (uintptr_t)kg->kg_completed; if (suword(addr, mbx)) { error = EFAULT; goto bad; } PROC_LOCK(p); if (mbx == (uintptr_t)kg->kg_completed) { kg->kg_completed = td->td_mailbox; /* * The thread context may be taken away by * other upcall threads when we unlock * process lock. it's no longer valid to * use it again in any other places. */ td->td_mailbox = NULL; PROC_UNLOCK(p); break; } PROC_UNLOCK(p); } td->td_usticks = 0; return (0); bad: PROC_LOCK(p); sigexit(td, SIGILL); return (error); } /* * Take the list of completed mailboxes for this KSEGRP and put them on this * upcall's mailbox as it's the next one going up. */ static int thread_link_mboxes(struct ksegrp *kg, struct kse_upcall *ku) { struct proc *p = kg->kg_proc; void *addr; uintptr_t mbx; addr = (void *)(&ku->ku_mailbox->km_completed); for (;;) { mbx = (uintptr_t)kg->kg_completed; if (suword(addr, mbx)) { PROC_LOCK(p); psignal(p, SIGSEGV); PROC_UNLOCK(p); return (EFAULT); } PROC_LOCK(p); if (mbx == (uintptr_t)kg->kg_completed) { kg->kg_completed = NULL; PROC_UNLOCK(p); break; } PROC_UNLOCK(p); } return (0); } /* * This function should be called at statclock interrupt time */ int thread_statclock(int user) { struct thread *td = curthread; if (!(td->td_pflags & TDP_SA)) return (0); if (user) { /* Current always do via ast() */ mtx_lock_spin(&sched_lock); td->td_flags |= TDF_ASTPENDING; mtx_unlock_spin(&sched_lock); td->td_uuticks++; } else if (td->td_mailbox != NULL) td->td_usticks++; return (0); } /* * Export state clock ticks for userland */ static int thread_update_usr_ticks(struct thread *td) { struct proc *p = td->td_proc; caddr_t addr; u_int uticks; if (td->td_mailbox == NULL) return (-1); if ((uticks = td->td_uuticks) != 0) { td->td_uuticks = 0; addr = (caddr_t)&td->td_mailbox->tm_uticks; if (suword32(addr, uticks+fuword32(addr))) goto error; } if ((uticks = td->td_usticks) != 0) { td->td_usticks = 0; addr = (caddr_t)&td->td_mailbox->tm_sticks; if (suword32(addr, uticks+fuword32(addr))) goto error; } return (0); error: PROC_LOCK(p); psignal(p, SIGSEGV); PROC_UNLOCK(p); return (-2); } /* * This function is intended to be used to initialize a spare thread * for upcall. Initialize thread's large data area outside sched_lock * for thread_schedule_upcall(). The crhold is also here to get it out * from the schedlock as it has a mutex op itself. */ void thread_alloc_spare(struct thread *td) { struct thread *spare; if (td->td_standin) return; spare = thread_alloc(); td->td_standin = spare; bzero(&spare->td_startzero, (unsigned) RANGEOF(struct thread, td_startzero, td_endzero)); spare->td_proc = td->td_proc; spare->td_ucred = crhold(td->td_ucred); } /* * Create a thread and schedule it for upcall on the KSE given. * Use our thread's standin so that we don't have to allocate one. */ struct thread * thread_schedule_upcall(struct thread *td, struct kse_upcall *ku) { struct thread *td2; mtx_assert(&sched_lock, MA_OWNED); /* * Schedule an upcall thread on specified kse_upcall, * the kse_upcall must be free. * td must have a spare thread. */ KASSERT(ku->ku_owner == NULL, ("%s: upcall has owner", __func__)); if ((td2 = td->td_standin) != NULL) { td->td_standin = NULL; } else { panic("no reserve thread when scheduling an upcall"); return (NULL); } CTR3(KTR_PROC, "thread_schedule_upcall: thread %p (pid %d, %s)", td2, td->td_proc->p_pid, td->td_proc->p_comm); /* * Bzero already done in thread_alloc_spare() because we can't * do the crhold here because we are in schedlock already. */ bcopy(&td->td_startcopy, &td2->td_startcopy, (unsigned) RANGEOF(struct thread, td_startcopy, td_endcopy)); thread_link(td2, ku->ku_ksegrp); /* inherit parts of blocked thread's context as a good template */ cpu_set_upcall(td2, td); /* Let the new thread become owner of the upcall */ ku->ku_owner = td2; td2->td_upcall = ku; td2->td_flags = 0; td2->td_pflags = TDP_SA|TDP_UPCALLING; td2->td_state = TDS_CAN_RUN; td2->td_inhibitors = 0; SIGFILLSET(td2->td_sigmask); SIG_CANTMASK(td2->td_sigmask); sched_fork_thread(td, td2); return (td2); /* bogus.. should be a void function */ } /* * It is only used when thread generated a trap and process is being * debugged. */ void thread_signal_add(struct thread *td, int sig) { struct proc *p; siginfo_t siginfo; struct sigacts *ps; int error; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); ps = p->p_sigacts; mtx_assert(&ps->ps_mtx, MA_OWNED); cpu_thread_siginfo(sig, 0, &siginfo); mtx_unlock(&ps->ps_mtx); SIGADDSET(td->td_sigmask, sig); PROC_UNLOCK(p); error = copyout(&siginfo, &td->td_mailbox->tm_syncsig, sizeof(siginfo)); if (error) { PROC_LOCK(p); sigexit(td, SIGSEGV); } PROC_LOCK(p); mtx_lock(&ps->ps_mtx); } #include "opt_sched.h" struct thread * thread_switchout(struct thread *td, int flags, struct thread *nextthread) { struct kse_upcall *ku; struct thread *td2; mtx_assert(&sched_lock, MA_OWNED); /* * If the outgoing thread is in threaded group and has never * scheduled an upcall, decide whether this is a short * or long term event and thus whether or not to schedule * an upcall. * If it is a short term event, just suspend it in * a way that takes its KSE with it. * Select the events for which we want to schedule upcalls. * For now it's just sleep or if thread is suspended but * process wide suspending flag is not set (debugger * suspends thread). * XXXKSE eventually almost any inhibition could do. */ if (TD_CAN_UNBIND(td) && (td->td_standin) && (TD_ON_SLEEPQ(td) || (TD_IS_SUSPENDED(td) && !P_SHOULDSTOP(td->td_proc)))) { /* * Release ownership of upcall, and schedule an upcall * thread, this new upcall thread becomes the owner of * the upcall structure. It will be ahead of us in the * run queue, so as we are stopping, it should either * start up immediatly, or at least before us if * we release our slot. */ ku = td->td_upcall; ku->ku_owner = NULL; td->td_upcall = NULL; td->td_pflags &= ~TDP_CAN_UNBIND; td2 = thread_schedule_upcall(td, ku); #ifdef SCHED_4BSD if (flags & SW_INVOL || nextthread) { setrunqueue(td2, SRQ_YIELDING); } else { /* Keep up with reality.. we have one extra thread * in the picture.. and it's 'running'. */ return td2; } #else setrunqueue(td2, SRQ_YIELDING); #endif } return (nextthread); } /* * Setup done on the thread when it enters the kernel. */ void thread_user_enter(struct thread *td) { struct ksegrp *kg; struct kse_upcall *ku; struct kse_thr_mailbox *tmbx; uint32_t flags; if (!(td->td_pflags & TDP_SA)) return; /* * If we are doing a syscall in a KSE environment, * note where our mailbox is. */ kg = td->td_ksegrp; ku = td->td_upcall; KASSERT(ku != NULL, ("no upcall owned")); KASSERT(ku->ku_owner == td, ("wrong owner")); KASSERT(!TD_CAN_UNBIND(td), ("can unbind")); if (td->td_standin == NULL) thread_alloc_spare(td); ku->ku_mflags = fuword32((void *)&ku->ku_mailbox->km_flags); tmbx = (void *)fuword((void *)&ku->ku_mailbox->km_curthread); if ((tmbx == NULL) || (tmbx == (void *)-1L) || (ku->ku_mflags & KMF_NOUPCALL)) { td->td_mailbox = NULL; } else { flags = fuword32(&tmbx->tm_flags); /* * On some architectures, TP register points to thread * mailbox but not points to kse mailbox, and userland * can not atomically clear km_curthread, but can * use TP register, and set TMF_NOUPCALL in thread * flag to indicate a critical region. */ if (flags & TMF_NOUPCALL) { td->td_mailbox = NULL; } else { td->td_mailbox = tmbx; td->td_pflags |= TDP_CAN_UNBIND; if (__predict_false(td->td_proc->p_flag & P_TRACED)) { flags = fuword32(&tmbx->tm_dflags); if (flags & TMDF_SUSPEND) { mtx_lock_spin(&sched_lock); /* fuword can block, check again */ if (td->td_upcall) ku->ku_flags |= KUF_DOUPCALL; mtx_unlock_spin(&sched_lock); } } } } } /* * The extra work we go through if we are a threaded process when we * return to userland. * * If we are a KSE process and returning to user mode, check for * extra work to do before we return (e.g. for more syscalls * to complete first). If we were in a critical section, we should * just return to let it finish. Same if we were in the UTS (in * which case the mailbox's context's busy indicator will be set). * The only traps we suport will have set the mailbox. * We will clear it here. */ int thread_userret(struct thread *td, struct trapframe *frame) { struct kse_upcall *ku; struct ksegrp *kg, *kg2; struct proc *p; struct timespec ts; int error = 0, upcalls, uts_crit; /* Nothing to do with bound thread */ if (!(td->td_pflags & TDP_SA)) return (0); /* * Update stat clock count for userland */ if (td->td_mailbox != NULL) { thread_update_usr_ticks(td); uts_crit = 0; } else { uts_crit = 1; } p = td->td_proc; kg = td->td_ksegrp; ku = td->td_upcall; /* * Optimisation: * This thread has not started any upcall. * If there is no work to report other than ourself, * then it can return direct to userland. */ if (TD_CAN_UNBIND(td)) { td->td_pflags &= ~TDP_CAN_UNBIND; if ((td->td_flags & TDF_NEEDSIGCHK) == 0 && (kg->kg_completed == NULL) && (ku->ku_flags & KUF_DOUPCALL) == 0 && (kg->kg_upquantum && ticks < kg->kg_nextupcall)) { nanotime(&ts); error = copyout(&ts, (caddr_t)&ku->ku_mailbox->km_timeofday, sizeof(ts)); td->td_mailbox = 0; ku->ku_mflags = 0; if (error) goto out; return (0); } thread_export_context(td, 0); /* * There is something to report, and we own an upcall * strucuture, we can go to userland. * Turn ourself into an upcall thread. */ td->td_pflags |= TDP_UPCALLING; } else if (td->td_mailbox && (ku == NULL)) { thread_export_context(td, 1); PROC_LOCK(p); if (kg->kg_upsleeps) wakeup(&kg->kg_completed); mtx_lock_spin(&sched_lock); thread_stopped(p); thread_exit(); /* NOTREACHED */ } KASSERT(ku != NULL, ("upcall is NULL")); KASSERT(TD_CAN_UNBIND(td) == 0, ("can unbind")); if (p->p_numthreads > max_threads_per_proc) { max_threads_hits++; PROC_LOCK(p); mtx_lock_spin(&sched_lock); p->p_maxthrwaits++; while (p->p_numthreads > max_threads_per_proc) { upcalls = 0; FOREACH_KSEGRP_IN_PROC(p, kg2) { if (kg2->kg_numupcalls == 0) upcalls++; else upcalls += kg2->kg_numupcalls; } if (upcalls >= max_threads_per_proc) break; mtx_unlock_spin(&sched_lock); if (msleep(&p->p_numthreads, &p->p_mtx, PPAUSE|PCATCH, "maxthreads", 0)) { mtx_lock_spin(&sched_lock); break; } else { mtx_lock_spin(&sched_lock); } } p->p_maxthrwaits--; mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); } if (td->td_pflags & TDP_UPCALLING) { uts_crit = 0; kg->kg_nextupcall = ticks+kg->kg_upquantum; /* * There is no more work to do and we are going to ride * this thread up to userland as an upcall. * Do the last parts of the setup needed for the upcall. */ CTR3(KTR_PROC, "userret: upcall thread %p (pid %d, %s)", td, td->td_proc->p_pid, td->td_proc->p_comm); td->td_pflags &= ~TDP_UPCALLING; if (ku->ku_flags & KUF_DOUPCALL) { mtx_lock_spin(&sched_lock); ku->ku_flags &= ~KUF_DOUPCALL; mtx_unlock_spin(&sched_lock); } /* * Set user context to the UTS */ if (!(ku->ku_mflags & KMF_NOUPCALL)) { cpu_set_upcall_kse(td, ku); if (p->p_flag & P_TRACED) ptrace_clear_single_step(td); error = suword32(&ku->ku_mailbox->km_lwp, td->td_tid); if (error) goto out; error = suword(&ku->ku_mailbox->km_curthread, 0); if (error) goto out; } /* * Unhook the list of completed threads. * anything that completes after this gets to * come in next time. * Put the list of completed thread mailboxes on * this KSE's mailbox. */ if (!(ku->ku_mflags & KMF_NOCOMPLETED) && (error = thread_link_mboxes(kg, ku)) != 0) goto out; } if (!uts_crit) { nanotime(&ts); error = copyout(&ts, &ku->ku_mailbox->km_timeofday, sizeof(ts)); } out: if (error) { /* * Things are going to be so screwed we should just kill * the process. * how do we do that? */ PROC_LOCK(td->td_proc); psignal(td->td_proc, SIGSEGV); PROC_UNLOCK(td->td_proc); } ku->ku_mflags = 0; td->td_mailbox = NULL; td->td_usticks = 0; return (error); /* go sync */ } int thread_upcall_check(struct thread *td) { PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); if (td->td_kflags & TDK_WAKEUP) return (1); else return (0); } /* * called after ptrace resumed a process, force all * virtual CPUs to schedule upcall for SA process, * because debugger may have changed something in userland, * we should notice UTS as soon as possible. */ void thread_continued(struct proc *p) { struct ksegrp *kg; struct kse_upcall *ku; struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); mtx_assert(&sched_lock, MA_OWNED); if (!(p->p_flag & P_SA)) return; if (p->p_flag & P_TRACED) { FOREACH_KSEGRP_IN_PROC(p, kg) { td = TAILQ_FIRST(&kg->kg_threads); if (td == NULL) continue; /* not a SA group, nothing to do */ if (!(td->td_pflags & TDP_SA)) continue; FOREACH_UPCALL_IN_GROUP(kg, ku) { ku->ku_flags |= KUF_DOUPCALL; wakeup(&kg->kg_completed); if (TD_IS_SUSPENDED(ku->ku_owner)) { thread_unsuspend_one(ku->ku_owner); } } } } }