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Annotation of sys/arch/i386/i386/lock_machdep.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: lock_machdep.c,v 1.6 2007/05/29 18:18:20 tom Exp $    */
                      2: /* $NetBSD: lock_machdep.c,v 1.1.2.3 2000/05/03 14:40:30 sommerfeld Exp $ */
                      3:
                      4: /*-
                      5:  * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
                      6:  * All rights reserved.
                      7:  *
                      8:  * This code is derived from software contributed to The NetBSD Foundation
                      9:  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
                     10:  * NASA Ames Research Center.
                     11:  *
                     12:  * Redistribution and use in source and binary forms, with or without
                     13:  * modification, are permitted provided that the following conditions
                     14:  * are met:
                     15:  * 1. Redistributions of source code must retain the above copyright
                     16:  *    notice, this list of conditions and the following disclaimer.
                     17:  * 2. Redistributions in binary form must reproduce the above copyright
                     18:  *    notice, this list of conditions and the following disclaimer in the
                     19:  *    documentation and/or other materials provided with the distribution.
                     20:  * 3. All advertising materials mentioning features or use of this software
                     21:  *    must display the following acknowledgement:
                     22:  *     This product includes software developed by the NetBSD
                     23:  *     Foundation, Inc. and its contributors.
                     24:  * 4. Neither the name of The NetBSD Foundation nor the names of its
                     25:  *    contributors may be used to endorse or promote products derived
                     26:  *    from this software without specific prior written permission.
                     27:  *
                     28:  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
                     29:  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
                     30:  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
                     31:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
                     32:  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
                     33:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
                     34:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
                     35:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
                     36:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
                     37:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
                     38:  * POSSIBILITY OF SUCH DAMAGE.
                     39:  */
                     40:
                     41: #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
                     42:
                     43: /*
                     44:  * Machine-dependent spin lock operations.
                     45:  */
                     46:
                     47: #include <sys/param.h>
                     48: #include <sys/lock.h>
                     49: #include <sys/systm.h>
                     50:
                     51: #include <machine/atomic.h>
                     52: #include <machine/lock.h>
                     53: #include <machine/cpufunc.h>
                     54:
                     55: #include <ddb/db_output.h>
                     56:
                     57: #ifdef LOCKDEBUG
                     58:
                     59: void
                     60: __cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
                     61: {
                     62:        *lockp = __SIMPLELOCK_UNLOCKED;
                     63: }
                     64:
                     65: #if defined (DEBUG) && defined(DDB)
                     66: int spin_limit = 10000000;
                     67: #endif
                     68:
                     69: void
                     70: __cpu_simple_lock(__cpu_simple_lock_t *lockp)
                     71: {
                     72: #if defined (DEBUG) && defined(DDB)
                     73:        int spincount = 0;
                     74: #endif
                     75:
                     76:        while (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
                     77:            == __SIMPLELOCK_LOCKED) {
                     78: #if defined(DEBUG) && defined(DDB)
                     79:                spincount++;
                     80:                if (spincount == spin_limit) {
                     81:                        extern int db_active;
                     82:                        db_printf("spundry\n");
                     83:                        if (db_active) {
                     84:                                db_printf("but already in debugger\n");
                     85:                        } else {
                     86:                                Debugger();
                     87:                        }
                     88:                }
                     89: #endif
                     90:        }
                     91: }
                     92:
                     93: int
                     94: __cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
                     95: {
                     96:
                     97:        if (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
                     98:            == __SIMPLELOCK_UNLOCKED)
                     99:                return (1);
                    100:        return (0);
                    101: }
                    102:
                    103: void
                    104: __cpu_simple_unlock(__cpu_simple_lock_t *lockp)
                    105: {
                    106:        *lockp = __SIMPLELOCK_UNLOCKED;
                    107: }
                    108:
                    109: #endif
                    110:
                    111: int
                    112: rw_cas_486(volatile unsigned long *p, unsigned long o, unsigned long n)
                    113: {
                    114:        return (i486_atomic_cas_int((u_int *)p, o, n) != o);
                    115: }