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NetBSD/sys/kern/sys_lwp.c

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/* $NetBSD: sys_lwp.c,v 1.44 2009/01/11 02:45:52 christos Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Nathan J. Williams, and Andrew Doran.
*
* 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, 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/
/*
* Lightweight process (LWP) system calls. See kern_lwp.c for a description
* of LWPs.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.44 2009/01/11 02:45:52 christos Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/pool.h>
#include <sys/proc.h>
#include <sys/types.h>
#include <sys/syscallargs.h>
#include <sys/kauth.h>
#include <sys/kmem.h>
#include <sys/sleepq.h>
#include <sys/lwpctl.h>
#include <uvm/uvm_extern.h>
#include "opt_sa.h"
#define LWP_UNPARK_MAX 1024
syncobj_t lwp_park_sobj = {
SOBJ_SLEEPQ_LIFO,
sleepq_unsleep,
sleepq_changepri,
sleepq_lendpri,
syncobj_noowner,
};
sleeptab_t lwp_park_tab;
void
lwp_sys_init(void)
{
sleeptab_init(&lwp_park_tab);
}
/* ARGSUSED */
int
sys__lwp_create(struct lwp *l, const struct sys__lwp_create_args *uap, register_t *retval)
{
/* {
syscallarg(const ucontext_t *) ucp;
syscallarg(u_long) flags;
syscallarg(lwpid_t *) new_lwp;
} */
struct proc *p = l->l_proc;
struct lwp *l2;
vaddr_t uaddr;
bool inmem;
ucontext_t *newuc;
int error, lid;
#ifdef KERN_SA
mutex_enter(p->p_lock);
if ((p->p_sflag & (PS_SA | PS_WEXIT)) != 0 || p->p_sa != NULL) {
mutex_exit(p->p_lock);
return EINVAL;
}
mutex_exit(p->p_lock);
#endif
newuc = pool_get(&lwp_uc_pool, PR_WAITOK);
error = copyin(SCARG(uap, ucp), newuc, p->p_emul->e_ucsize);
if (error) {
pool_put(&lwp_uc_pool, newuc);
return error;
}
/* XXX check against resource limits */
inmem = uvm_uarea_alloc(&uaddr);
if (__predict_false(uaddr == 0)) {
pool_put(&lwp_uc_pool, newuc);
return ENOMEM;
}
error = lwp_create(l, p, uaddr, inmem, SCARG(uap, flags) & LWP_DETACHED,
NULL, 0, p->p_emul->e_startlwp, newuc, &l2, l->l_class);
if (error) {
uvm_uarea_free(uaddr, curcpu());
pool_put(&lwp_uc_pool, newuc);
return error;
}
lid = l2->l_lid;
error = copyout(&lid, SCARG(uap, new_lwp), sizeof(lid));
if (error) {
lwp_exit(l2);
pool_put(&lwp_uc_pool, newuc);
return error;
}
/*
* Set the new LWP running, unless the caller has requested that
* it be created in suspended state. If the process is stopping,
* then the LWP is created stopped.
*/
mutex_enter(p->p_lock);
lwp_lock(l2);
if ((SCARG(uap, flags) & LWP_SUSPENDED) == 0 &&
(l->l_flag & (LW_WREBOOT | LW_WSUSPEND | LW_WEXIT)) == 0) {
if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0)
l2->l_stat = LSSTOP;
else {
KASSERT(lwp_locked(l2, l2->l_cpu->ci_schedstate.spc_mutex));
p->p_nrlwps++;
l2->l_stat = LSRUN;
sched_enqueue(l2, false);
}
lwp_unlock(l2);
} else {
l2->l_stat = LSSUSPENDED;
lwp_unlock_to(l2, l2->l_cpu->ci_schedstate.spc_lwplock);
}
mutex_exit(p->p_lock);
return 0;
}
int
sys__lwp_exit(struct lwp *l, const void *v, register_t *retval)
{
lwp_exit(l);
return 0;
}
int
sys__lwp_self(struct lwp *l, const void *v, register_t *retval)
{
*retval = l->l_lid;
return 0;
}
int
sys__lwp_getprivate(struct lwp *l, const void *v, register_t *retval)
{
*retval = (uintptr_t)l->l_private;
return 0;
}
int
sys__lwp_setprivate(struct lwp *l, const struct sys__lwp_setprivate_args *uap, register_t *retval)
{
/* {
syscallarg(void *) ptr;
} */
l->l_private = SCARG(uap, ptr);
return 0;
}
int
sys__lwp_suspend(struct lwp *l, const struct sys__lwp_suspend_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
} */
struct proc *p = l->l_proc;
struct lwp *t;
int error;
mutex_enter(p->p_lock);
#ifdef KERN_SA
if ((p->p_sflag & PS_SA) != 0 || p->p_sa != NULL) {
mutex_exit(p->p_lock);
return EINVAL;
}
#endif
if ((t = lwp_find(p, SCARG(uap, target))) == NULL) {
mutex_exit(p->p_lock);
return ESRCH;
}
/*
* Check for deadlock, which is only possible when we're suspending
* ourself. XXX There is a short race here, as p_nrlwps is only
* incremented when an LWP suspends itself on the kernel/user
* boundary. It's still possible to kill -9 the process so we
* don't bother checking further.
*/
lwp_lock(t);
if ((t == l && p->p_nrlwps == 1) ||
(l->l_flag & (LW_WCORE | LW_WEXIT)) != 0) {
lwp_unlock(t);
mutex_exit(p->p_lock);
return EDEADLK;
}
/*
* Suspend the LWP. XXX If it's on a different CPU, we should wait
* for it to be preempted, where it will put itself to sleep.
*
* Suspension of the current LWP will happen on return to userspace.
*/
error = lwp_suspend(l, t);
if (error) {
mutex_exit(p->p_lock);
return error;
}
/*
* Wait for:
* o process exiting
* o target LWP suspended
* o target LWP not suspended and L_WSUSPEND clear
* o target LWP exited
*/
for (;;) {
error = cv_wait_sig(&p->p_lwpcv, p->p_lock);
if (error) {
error = ERESTART;
break;
}
if (lwp_find(p, SCARG(uap, target)) == NULL) {
error = ESRCH;
break;
}
if ((l->l_flag | t->l_flag) & (LW_WCORE | LW_WEXIT)) {
error = ERESTART;
break;
}
if (t->l_stat == LSSUSPENDED ||
(t->l_flag & LW_WSUSPEND) == 0)
break;
}
mutex_exit(p->p_lock);
return error;
}
int
sys__lwp_continue(struct lwp *l, const struct sys__lwp_continue_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
} */
int error;
struct proc *p = l->l_proc;
struct lwp *t;
error = 0;
mutex_enter(p->p_lock);
if ((t = lwp_find(p, SCARG(uap, target))) == NULL) {
mutex_exit(p->p_lock);
return ESRCH;
}
lwp_lock(t);
lwp_continue(t);
mutex_exit(p->p_lock);
return error;
}
int
sys__lwp_wakeup(struct lwp *l, const struct sys__lwp_wakeup_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
} */
struct lwp *t;
struct proc *p;
int error;
p = l->l_proc;
mutex_enter(p->p_lock);
if ((t = lwp_find(p, SCARG(uap, target))) == NULL) {
mutex_exit(p->p_lock);
return ESRCH;
}
lwp_lock(t);
t->l_flag |= (LW_CANCELLED | LW_UNPARKED);
if (t->l_stat != LSSLEEP) {
lwp_unlock(t);
error = ENODEV;
} else if ((t->l_flag & LW_SINTR) == 0) {
lwp_unlock(t);
error = EBUSY;
} else {
/* Wake it up. lwp_unsleep() will release the LWP lock. */
(void)lwp_unsleep(t, true);
error = 0;
}
mutex_exit(p->p_lock);
return error;
}
int
sys__lwp_wait(struct lwp *l, const struct sys__lwp_wait_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) wait_for;
syscallarg(lwpid_t *) departed;
} */
struct proc *p = l->l_proc;
int error;
lwpid_t dep;
mutex_enter(p->p_lock);
error = lwp_wait1(l, SCARG(uap, wait_for), &dep, 0);
mutex_exit(p->p_lock);
if (error)
return error;
if (SCARG(uap, departed)) {
error = copyout(&dep, SCARG(uap, departed), sizeof(dep));
if (error)
return error;
}
return 0;
}
/* ARGSUSED */
int
sys__lwp_kill(struct lwp *l, const struct sys__lwp_kill_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
syscallarg(int) signo;
} */
struct proc *p = l->l_proc;
struct lwp *t;
ksiginfo_t ksi;
int signo = SCARG(uap, signo);
int error = 0;
if ((u_int)signo >= NSIG)
return EINVAL;
KSI_INIT(&ksi);
ksi.ksi_signo = signo;
ksi.ksi_code = SI_LWP;
ksi.ksi_pid = p->p_pid;
ksi.ksi_uid = kauth_cred_geteuid(l->l_cred);
ksi.ksi_lid = SCARG(uap, target);
mutex_enter(proc_lock);
mutex_enter(p->p_lock);
if ((t = lwp_find(p, ksi.ksi_lid)) == NULL)
error = ESRCH;
else if (signo != 0)
kpsignal2(p, &ksi);
mutex_exit(p->p_lock);
mutex_exit(proc_lock);
return error;
}
int
sys__lwp_detach(struct lwp *l, const struct sys__lwp_detach_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
} */
struct proc *p;
struct lwp *t;
lwpid_t target;
int error;
target = SCARG(uap, target);
p = l->l_proc;
mutex_enter(p->p_lock);
if (l->l_lid == target)
t = l;
else {
/*
* We can't use lwp_find() here because the target might
* be a zombie.
*/
LIST_FOREACH(t, &p->p_lwps, l_sibling)
if (t->l_lid == target)
break;
}
/*
* If the LWP is already detached, there's nothing to do.
* If it's a zombie, we need to clean up after it. LSZOMB
* is visible with the proc mutex held.
*
* After we have detached or released the LWP, kick any
* other LWPs that may be sitting in _lwp_wait(), waiting
* for the target LWP to exit.
*/
if (t != NULL && t->l_stat != LSIDL) {
if ((t->l_prflag & LPR_DETACHED) == 0) {
p->p_ndlwps++;
t->l_prflag |= LPR_DETACHED;
if (t->l_stat == LSZOMB) {
/* Releases proc mutex. */
lwp_free(t, false, false);
return 0;
}
error = 0;
/*
* Have any LWPs sleeping in lwp_wait() recheck
* for deadlock.
*/
cv_broadcast(&p->p_lwpcv);
} else
error = EINVAL;
} else
error = ESRCH;
mutex_exit(p->p_lock);
return error;
}
static inline wchan_t
lwp_park_wchan(struct proc *p, const void *hint)
{
return (wchan_t)((uintptr_t)p ^ (uintptr_t)hint);
}
int
lwp_unpark(lwpid_t target, const void *hint)
{
sleepq_t *sq;
wchan_t wchan;
int swapin;
kmutex_t *mp;
proc_t *p;
lwp_t *t;
/*
* Easy case: search for the LWP on the sleep queue. If
* it's parked, remove it from the queue and set running.
*/
p = curproc;
wchan = lwp_park_wchan(p, hint);
sq = sleeptab_lookup(&lwp_park_tab, wchan, &mp);
TAILQ_FOREACH(t, sq, l_sleepchain)
if (t->l_proc == p && t->l_lid == target)
break;
if (__predict_true(t != NULL)) {
swapin = sleepq_remove(sq, t);
mutex_spin_exit(mp);
if (swapin)
uvm_kick_scheduler();
return 0;
}
/*
* The LWP hasn't parked yet. Take the hit and mark the
* operation as pending.
*/
mutex_spin_exit(mp);
mutex_enter(p->p_lock);
if ((t = lwp_find(p, target)) == NULL) {
mutex_exit(p->p_lock);
return ESRCH;
}
/*
* It may not have parked yet, we may have raced, or it
* is parked on a different user sync object.
*/
lwp_lock(t);
if (t->l_syncobj == &lwp_park_sobj) {
/* Releases the LWP lock. */
(void)lwp_unsleep(t, true);
} else {
/*
* Set the operation pending. The next call to _lwp_park
* will return early.
*/
t->l_flag |= LW_UNPARKED;
lwp_unlock(t);
}
mutex_exit(p->p_lock);
return 0;
}
int
lwp_park(struct timespec *ts, const void *hint)
{
struct timespec tsx;
sleepq_t *sq;
kmutex_t *mp;
wchan_t wchan;
int timo, error;
lwp_t *l;
/* Fix up the given timeout value. */
if (ts != NULL) {
getnanotime(&tsx);
timespecsub(ts, &tsx, &tsx);
if (tsx.tv_sec < 0 || (tsx.tv_sec == 0 && tsx.tv_nsec <= 0))
return ETIMEDOUT;
if ((error = itimespecfix(&tsx)) != 0)
return error;
timo = tstohz(&tsx);
KASSERT(timo != 0);
} else
timo = 0;
/* Find and lock the sleep queue. */
l = curlwp;
wchan = lwp_park_wchan(l->l_proc, hint);
sq = sleeptab_lookup(&lwp_park_tab, wchan, &mp);
/*
* Before going the full route and blocking, check to see if an
* unpark op is pending.
*/
lwp_lock(l);
if ((l->l_flag & (LW_CANCELLED | LW_UNPARKED)) != 0) {
l->l_flag &= ~(LW_CANCELLED | LW_UNPARKED);
lwp_unlock(l);
mutex_spin_exit(mp);
return EALREADY;
}
lwp_unlock_to(l, mp);
l->l_biglocks = 0;
sleepq_enqueue(sq, wchan, "parked", &lwp_park_sobj);
error = sleepq_block(timo, true);
switch (error) {
case EWOULDBLOCK:
error = ETIMEDOUT;
break;
case ERESTART:
error = EINTR;
break;
default:
/* nothing */
break;
}
return error;
}
/*
* 'park' an LWP waiting on a user-level synchronisation object. The LWP
* will remain parked until another LWP in the same process calls in and
* requests that it be unparked.
*/
int
sys____lwp_park50(struct lwp *l, const struct sys____lwp_park50_args *uap,
register_t *retval)
{
/* {
syscallarg(const struct timespec *) ts;
syscallarg(lwpid_t) unpark;
syscallarg(const void *) hint;
syscallarg(const void *) unparkhint;
} */
struct timespec ts, *tsp;
int error;
if (SCARG(uap, ts) == NULL)
tsp = NULL;
else {
error = copyin(SCARG(uap, ts), &ts, sizeof(ts));
if (error != 0)
return error;
tsp = &ts;
}
if (SCARG(uap, unpark) != 0) {
error = lwp_unpark(SCARG(uap, unpark), SCARG(uap, unparkhint));
if (error != 0)
return error;
}
return lwp_park(tsp, SCARG(uap, hint));
}
int
sys__lwp_unpark(struct lwp *l, const struct sys__lwp_unpark_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
syscallarg(const void *) hint;
} */
return lwp_unpark(SCARG(uap, target), SCARG(uap, hint));
}
int
sys__lwp_unpark_all(struct lwp *l, const struct sys__lwp_unpark_all_args *uap, register_t *retval)
{
/* {
syscallarg(const lwpid_t *) targets;
syscallarg(size_t) ntargets;
syscallarg(const void *) hint;
} */
struct proc *p;
struct lwp *t;
sleepq_t *sq;
wchan_t wchan;
lwpid_t targets[32], *tp, *tpp, *tmax, target;
int swapin, error;
kmutex_t *mp;
u_int ntargets;
size_t sz;
p = l->l_proc;
ntargets = SCARG(uap, ntargets);
if (SCARG(uap, targets) == NULL) {
/*
* Let the caller know how much we are willing to do, and
* let it unpark the LWPs in blocks.
*/
*retval = LWP_UNPARK_MAX;
return 0;
}
if (ntargets > LWP_UNPARK_MAX || ntargets == 0)
return EINVAL;
/*
* Copy in the target array. If it's a small number of LWPs, then
* place the numbers on the stack.
*/
sz = sizeof(target) * ntargets;
if (sz <= sizeof(targets))
tp = targets;
else {
tp = kmem_alloc(sz, KM_SLEEP);
if (tp == NULL)
return ENOMEM;
}
error = copyin(SCARG(uap, targets), tp, sz);
if (error != 0) {
if (tp != targets) {
kmem_free(tp, sz);
}
return error;
}
swapin = 0;
wchan = lwp_park_wchan(p, SCARG(uap, hint));
sq = sleeptab_lookup(&lwp_park_tab, wchan, &mp);
for (tmax = tp + ntargets, tpp = tp; tpp < tmax; tpp++) {
target = *tpp;
/*
* Easy case: search for the LWP on the sleep queue. If
* it's parked, remove it from the queue and set running.
*/
TAILQ_FOREACH(t, sq, l_sleepchain)
if (t->l_proc == p && t->l_lid == target)
break;
if (t != NULL) {
swapin |= sleepq_remove(sq, t);
continue;
}
/*
* The LWP hasn't parked yet. Take the hit and
* mark the operation as pending.
*/
mutex_spin_exit(mp);
mutex_enter(p->p_lock);
if ((t = lwp_find(p, target)) == NULL) {
mutex_exit(p->p_lock);
mutex_spin_enter(mp);
continue;
}
lwp_lock(t);
/*
* It may not have parked yet, we may have raced, or
* it is parked on a different user sync object.
*/
if (t->l_syncobj == &lwp_park_sobj) {
/* Releases the LWP lock. */
(void)lwp_unsleep(t, true);
} else {
/*
* Set the operation pending. The next call to
* _lwp_park will return early.
*/
t->l_flag |= LW_UNPARKED;
lwp_unlock(t);
}
mutex_exit(p->p_lock);
mutex_spin_enter(mp);
}
mutex_spin_exit(mp);
if (tp != targets)
kmem_free(tp, sz);
if (swapin)
uvm_kick_scheduler();
return 0;
}
int
sys__lwp_setname(struct lwp *l, const struct sys__lwp_setname_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
syscallarg(const char *) name;
} */
char *name, *oname;
lwpid_t target;
proc_t *p;
lwp_t *t;
int error;
if ((target = SCARG(uap, target)) == 0)
target = l->l_lid;
name = kmem_alloc(MAXCOMLEN, KM_SLEEP);
if (name == NULL)
return ENOMEM;
error = copyinstr(SCARG(uap, name), name, MAXCOMLEN, NULL);
switch (error) {
case ENAMETOOLONG:
case 0:
name[MAXCOMLEN - 1] = '\0';
break;
default:
kmem_free(name, MAXCOMLEN);
return error;
}
p = curproc;
mutex_enter(p->p_lock);
if ((t = lwp_find(p, target)) == NULL) {
mutex_exit(p->p_lock);
kmem_free(name, MAXCOMLEN);
return ESRCH;
}
lwp_lock(t);
oname = t->l_name;
t->l_name = name;
lwp_unlock(t);
mutex_exit(p->p_lock);
if (oname != NULL)
kmem_free(oname, MAXCOMLEN);
return 0;
}
int
sys__lwp_getname(struct lwp *l, const struct sys__lwp_getname_args *uap, register_t *retval)
{
/* {
syscallarg(lwpid_t) target;
syscallarg(char *) name;
syscallarg(size_t) len;
} */
char name[MAXCOMLEN];
lwpid_t target;
proc_t *p;
lwp_t *t;
if ((target = SCARG(uap, target)) == 0)
target = l->l_lid;
p = curproc;
mutex_enter(p->p_lock);
if ((t = lwp_find(p, target)) == NULL) {
mutex_exit(p->p_lock);
return ESRCH;
}
lwp_lock(t);
if (t->l_name == NULL)
name[0] = '\0';
else
strcpy(name, t->l_name);
lwp_unlock(t);
mutex_exit(p->p_lock);
return copyoutstr(name, SCARG(uap, name), SCARG(uap, len), NULL);
}
int
sys__lwp_ctl(struct lwp *l, const struct sys__lwp_ctl_args *uap, register_t *retval)
{
/* {
syscallarg(int) features;
syscallarg(struct lwpctl **) address;
} */
int error, features;
vaddr_t vaddr;
features = SCARG(uap, features);
features &= ~(LWPCTL_FEATURE_CURCPU | LWPCTL_FEATURE_PCTR);
if (features != 0)
return ENODEV;
if ((error = lwp_ctl_alloc(&vaddr)) != 0)
return error;
return copyout(&vaddr, SCARG(uap, address), sizeof(void *));
}
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