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Annotation of sys/arch/i386/i386/lock_machdep.c, Revision 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: }