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kern_kthread.c revision 1.16.6.3 
      1 /*	$NetBSD: kern_kthread.c,v 1.16.6.3 2007/04/10 18:34:46 ad Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998, 1999, 2007 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center, and by Andrew Doran.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the NetBSD
     22  *	Foundation, Inc. and its contributors.
     23  * 4. Neither the name of The NetBSD Foundation nor the names of its
     24  *    contributors may be used to endorse or promote products derived
     25  *    from this software without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     37  * POSSIBILITY OF SUCH DAMAGE.
     38  */
     39 
     40 #include <sys/cdefs.h>
     41 __KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.16.6.3 2007/04/10 18:34:46 ad Exp $");
     42 
     43 #include <sys/param.h>
     44 #include <sys/systm.h>
     45 #include <sys/kernel.h>
     46 #include <sys/kthread.h>
     47 #include <sys/proc.h>
     48 
     49 #include <uvm/uvm_extern.h>
     50 
     51 /*
     52  * note that stdarg.h and the ansi style va_start macro is used for both
     53  * ansi and traditional c complers.
     54  * XXX: this requires that stdarg.h define: va_alist and va_dcl
     55  */
     56 #include <machine/stdarg.h>
     57 
     58 /*
     59  * Fork a kernel thread.  Any process can request this to be done.
     60  */
     61 int
     62 kthread_create(pri_t pri, bool mpsafe, void (*func)(void *), void *arg,
     63 	       lwp_t **lp, const char *fmt, ...)
     64 {
     65 	lwp_t *l;
     66 	vaddr_t uaddr;
     67 	bool inmem;
     68 	int error;
     69 	va_list ap;
     70 
     71 	inmem = uvm_uarea_alloc(&uaddr);
     72 	if (uaddr == 0)
     73 		return ENOMEM;
     74 	error = newlwp(&lwp0, &proc0, uaddr, inmem, LWP_DETACHED, NULL, 0,
     75 	    func, arg, &l);
     76 	if (error) {
     77 		uvm_uarea_free(uaddr);
     78 		return error;
     79 	}
     80 
     81 	/* Set parameters. */
     82 	if (pri == PRI_NONE) {
     83 		/* Minimum kernel priority level. */
     84 		pri = PUSER - 1;
     85 	}
     86 	if (mpsafe)
     87 		l->l_pflag |= LP_MPSAFE;
     88 	if (fmt != NULL) {
     89 		va_start(ap, fmt);
     90 		vsnprintf(l->l_name, MAXCOMLEN, fmt, ap);
     91 		va_end(ap);
     92 	}
     93 
     94 	/* Set the new LWP running. */
     95 	mutex_enter(&proc0.p_smutex);
     96 	lwp_lock(l);
     97 	l->l_usrpri = pri;
     98 	l->l_priority = pri;
     99 	l->l_stat = LSRUN;
    100 	proc0.p_nrlwps++;
    101 	setrunqueue(l);
    102 	lwp_unlock(l);
    103 	mutex_exit(&proc0.p_smutex);
    104 
    105 	/* All done! */
    106 	if (lp != NULL)
    107 		*lp = l;
    108 
    109 	return (0);
    110 }
    111 
    112 /*
    113  * Cause a kernel thread to exit.  Assumes the exiting thread is the
    114  * current context.
    115  */
    116 void
    117 kthread_exit(int ecode)
    118 {
    119 	lwp_t *l = curlwp;
    120 
    121 	/* We can't do much with the exit code, so just report it. */
    122 	if (ecode != 0)
    123 		printf("WARNING: kthread `%s' (%d) exits with status %d\n",
    124 		    l->l_name, l->l_lid, ecode);
    125 
    126 	/* And exit.. */
    127 	lwp_exit(l);
    128 
    129 	/*
    130 	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
    131 	 * XXX of worms right now.
    132 	 */
    133 	for (;;)
    134 		;
    135 }
    136