FreeBSD-5.3/sys/kern/kern_kse.c
/*
* Copyright (C) 2001 Julian Elischer <julian@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(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 <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/kern_kse.c,v 1.193.2.10 2004/10/09 10:36:32 julian Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
#include <sys/smp.h>
#include <sys/sysproto.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/sleepqueue.h>
#include <sys/kse.h>
#include <sys/ktr.h>
#include <vm/uma.h>
/*
* 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.
*/
thread_unthread(td);
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;
kg = td->td_ksegrp;
if ((err = copyin(uap->mbx, &mbx, sizeof(mbx))))
return (err);
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);
/*
* Processes using the other threading model can't
* suddenly start calling this one
*/
if ((p->p_flag & (P_SA|P_HADTHREADS)) == P_HADTHREADS) {
PROC_UNLOCK(p);
return (EINVAL);
}
/*
* Limit it to NCPU upcall contexts per ksegrp in any case.
* There is a small race here as we don't hold proclock
* until we inc the ksegrp count, but it's not really a big problem
* if we get one too many, but we save a proc lock.
*/
if ((!uap->newgroup) && (kg->kg_numupcalls >= ncpus)) {
PROC_UNLOCK(p);
return (EPROCLIM);
}
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);
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));
sched_init_concurrency(newkg);
PROC_LOCK(p);
if (p->p_numksegrps >= max_groups_per_proc) {
PROC_UNLOCK(p);
ksegrp_free(newkg);
return (EPROCLIM);
}
ksegrp_link(newkg, p);
mtx_lock_spin(&sched_lock);
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);
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.
* XXX BUG.. we need to get the cr ref after the thread has
* checked and chenged its own, not 6 months before...
*/
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 proc *p = td->td_proc;
struct ksegrp *kg;
struct kse_upcall *ku;
struct kse_thr_mailbox *tmbx;
uint32_t flags;
/*
* First check that we shouldn't just abort. we
* can suspend it here or just exit.
*/
if (__predict_false(P_SHOULDSTOP(p))) {
PROC_LOCK(p);
thread_suspend_check(0);
PROC_UNLOCK(p);
}
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(p->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, p->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(p);
psignal(p, SIGSEGV);
PROC_UNLOCK(p);
} else {
/*
* Optimisation:
* Ensure that we have a spare thread available,
* for when we re-enter the kernel.
*/
if (td->td_standin == NULL)
thread_alloc_spare(td);
}
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);
}
}
}
}
}