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sys_lwp.c revision 1.1.2.1 
      1 /*	$NetBSD: sys_lwp.c,v 1.1.2.1 2006/10/21 14:26:41 ad Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2001, 2006 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nathan J. Williams, and Andrew Doran.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 __KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.1.2.1 2006/10/21 14:26:41 ad Exp $");
     41 
     42 #include <sys/param.h>
     43 #include <sys/systm.h>
     44 #include <sys/pool.h>
     45 #include <sys/proc.h>
     46 #include <sys/sa.h>
     47 #include <sys/savar.h>
     48 #include <sys/types.h>
     49 #include <sys/syscallargs.h>
     50 
     51 #include <uvm/uvm_extern.h>
     52 
     53 /* ARGSUSED */
     54 int
     55 sys__lwp_create(struct lwp *l, void *v, register_t *retval)
     56 {
     57 	struct sys__lwp_create_args /* {
     58 		syscallarg(const ucontext_t *) ucp;
     59 		syscallarg(u_long) flags;
     60 		syscallarg(lwpid_t *) new_lwp;
     61 	} */ *uap = v;
     62 	struct proc *p = l->l_proc;
     63 	struct lwp *l2;
     64 	vaddr_t uaddr;
     65 	boolean_t inmem;
     66 	ucontext_t *newuc;
     67 	int error, lid;
     68 
     69 	mutex_enter(&p->p_smutex);
     70 	if (p->p_flag & (P_SA | P_WEXIT)) {
     71 		mutex_exit(&p->p_smutex);
     72 		return EINVAL;
     73 	}
     74 	/* XXXAD p->p_flag |= P_NOSA; */
     75 	mutex_exit(&p->p_smutex);
     76 
     77 	newuc = pool_get(&lwp_uc_pool, PR_WAITOK);
     78 
     79 	error = copyin(SCARG(uap, ucp), newuc,
     80 	    l->l_proc->p_emul->e_sa->sae_ucsize);
     81 	if (error) {
     82 		pool_put(&lwp_uc_pool, newuc);
     83 		return (error);
     84 	}
     85 
     86 	/* XXX check against resource limits */
     87 
     88 	inmem = uvm_uarea_alloc(&uaddr);
     89 	if (__predict_false(uaddr == 0)) {
     90 		pool_put(&lwp_uc_pool, newuc);
     91 		return (ENOMEM);
     92 	}
     93 
     94 	/* XXX flags:
     95 	 * __LWP_ASLWP is probably needed for Solaris compat.
     96 	 */
     97 
     98 	newlwp(l, p, uaddr, inmem,
     99 	    SCARG(uap, flags) & LWP_DETACHED,
    100 	    NULL, 0, startlwp, newuc, &l2);
    101 
    102 	mutex_enter(&p->p_smutex);
    103 	lwp_lock(l2);
    104 	lid = l2->l_lid;
    105 	if ((SCARG(uap, flags) & LWP_SUSPENDED) == 0) {
    106 		p->p_nrlwps++;
    107 		l2->l_stat = LSRUN;
    108 		mutex_enter(&sched_mutex);
    109 		lwp_swaplock_linked(l2, &sched_mutex);
    110 		setrunqueue(l2);
    111 	} else
    112 		l2->l_stat = LSSUSPENDED;
    113 	lwp_unlock(l2);
    114 	mutex_exit(&p->p_smutex);
    115 
    116 	error = copyout(&lid, SCARG(uap, new_lwp), sizeof(lid));
    117 	if (error) {
    118 		/* XXX We should destroy the LWP. */
    119 		return (error);
    120 	}
    121 
    122 	return (0);
    123 }
    124 
    125 int
    126 sys__lwp_exit(struct lwp *l, void *v, register_t *retval)
    127 {
    128 
    129 	lwp_exit(l);
    130 	/* NOTREACHED */
    131 	return (0);
    132 }
    133 
    134 int
    135 sys__lwp_self(struct lwp *l, void *v, register_t *retval)
    136 {
    137 
    138 	*retval = l->l_lid;
    139 
    140 	return (0);
    141 }
    142 
    143 int
    144 sys__lwp_getprivate(struct lwp *l, void *v, register_t *retval)
    145 {
    146 
    147 	mb_read();
    148 	*retval = (uintptr_t) l->l_private;
    149 
    150 	return (0);
    151 }
    152 
    153 int
    154 sys__lwp_setprivate(struct lwp *l, void *v, register_t *retval)
    155 {
    156 	struct sys__lwp_setprivate_args /* {
    157 		syscallarg(void *) ptr;
    158 	} */ *uap = v;
    159 
    160 	l->l_private = SCARG(uap, ptr);
    161 	mb_write();
    162 
    163 	return (0);
    164 }
    165 
    166 int
    167 sys__lwp_suspend(struct lwp *l, void *v, register_t *retval)
    168 {
    169 	struct sys__lwp_suspend_args /* {
    170 		syscallarg(lwpid_t) target;
    171 	} */ *uap = v;
    172 	struct proc *p = l->l_proc;
    173 	struct lwp *t;
    174 	int error;
    175 
    176 	mutex_enter(&p->p_smutex);
    177 
    178 	if (p->p_flag & P_SA) {
    179 		mutex_exit(&p->p_smutex);
    180 		return EINVAL;
    181 	}
    182 
    183 	if ((t = lwp_byid(p, SCARG(uap, target))) == NULL) {
    184 		mutex_exit(&p->p_smutex);
    185 		return (ESRCH);
    186 	}
    187 
    188 	/*
    189 	 * Check for deadlock, which is only possible when we're suspending
    190 	 * ourself.
    191 	 */
    192 	if (t == l && l->l_stat == LSONPROC && p->p_nrlwps == 1) {
    193 		lwp_unlock(l);
    194 		mutex_exit(&p->p_smutex);
    195 		return (EDEADLK);
    196 	}
    197 
    198 	/*
    199 	 * Suspend the LWP.  If it's on a different CPU, we need to wait for
    200 	 * it to be preempted, where it will put itself to sleep.  If not
    201 	 * suspending ourselves, the LWP will be returned unlocked.
    202 	 */
    203 	error = lwp_halt(l, t, LSSUSPENDED);
    204 	mutex_exit(&p->p_smutex);
    205 
    206 	/*
    207 	 * If we suspended ourself, we need to sleep now.
    208 	 */
    209 	if (t == l && !error) {
    210 		lwp_lock(l);
    211 		l->l_nvcsw++;
    212 		mi_switch(t, NULL);
    213 	}
    214 
    215 	return (error);
    216 }
    217 
    218 int
    219 sys__lwp_continue(struct lwp *l, void *v, register_t *retval)
    220 {
    221 	struct sys__lwp_continue_args /* {
    222 		syscallarg(lwpid_t) target;
    223 	} */ *uap = v;
    224 	int error;
    225 	struct proc *p = l->l_proc;
    226 	struct lwp *t;
    227 
    228 	error = 0;
    229 
    230 	mutex_enter(&p->p_smutex);
    231 
    232 	if (p->p_flag & P_SA)
    233 		error = EINVAL;
    234 	else if ((t = lwp_byid(p, SCARG(uap, target))) == NULL)
    235 		error = ESRCH;
    236 	else if (t == l || t->l_stat != LSSUSPENDED)
    237 		lwp_unlock(t);
    238 	else
    239 		lwp_continue(t);
    240 
    241 	mutex_exit(&p->p_smutex);
    242 
    243 	return (error);
    244 }
    245 
    246 int
    247 sys__lwp_wakeup(struct lwp *l, void *v, register_t *retval)
    248 {
    249 	struct sys__lwp_wakeup_args /* {
    250 		syscallarg(lwpid_t) target;
    251 	} */ *uap = v;
    252 	struct lwp *t;
    253 	struct proc *p;
    254 	int error;
    255 
    256 	p = l->l_proc;
    257 	mutex_enter(&p->p_smutex);
    258 
    259 	if ((t = lwp_byid(p, SCARG(uap, target))) == NULL) {
    260 		mutex_exit(&p->p_smutex);
    261 		return ESRCH;
    262 	}
    263 
    264 	if (t->l_stat != LSSLEEP) {
    265 		error = ENODEV;
    266 		goto bad;
    267 	}
    268 
    269 	if ((t->l_flag & L_SINTR) == 0) {
    270 		error = EBUSY;
    271 		goto bad;
    272 	}
    273 
    274 	/*
    275 	 * Tell ltsleep to wakeup.  setrunnable() will release the mutex.
    276 	 */
    277 	t->l_flag |= L_CANCELLED;
    278 	setrunnable(t);
    279 	mutex_exit(&p->p_smutex);
    280 	return 0;
    281 
    282  bad:
    283  	lwp_unlock(l);
    284 	mutex_exit(&p->p_smutex);
    285 	return error;
    286 }
    287 
    288 int
    289 sys__lwp_wait(struct lwp *l, void *v, register_t *retval)
    290 {
    291 	struct sys__lwp_wait_args /* {
    292 		syscallarg(lwpid_t) wait_for;
    293 		syscallarg(lwpid_t *) departed;
    294 	} */ *uap = v;
    295 	struct proc *p = l->l_proc;
    296 	int error;
    297 	lwpid_t dep;
    298 
    299 	mutex_enter(&p->p_smutex);
    300 	error = lwp_wait1(l, SCARG(uap, wait_for), &dep, 0);
    301 	mutex_exit(&p->p_smutex);
    302 	if (error)
    303 		return (error);
    304 
    305 	if (SCARG(uap, departed)) {
    306 		error = copyout(&dep, SCARG(uap, departed),
    307 		    sizeof(dep));
    308 		if (error)
    309 			return (error);
    310 	}
    311 
    312 	return (0);
    313 }
    314