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Annotation of src/sys/arch/alpha/include/lock.h, Revision 1.16

1.16    ! thorpej     1: /* $NetBSD: lock.h,v 1.15 2001/04/20 22:58:40 thorpej Exp $ */
1.1       thorpej     2:
                      3: /*-
1.9       thorpej     4:  * Copyright (c) 1998, 1999, 2000 The NetBSD Foundation, Inc.
1.1       thorpej     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.
                     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: /*
                     41:  * Machine-dependent spin lock operations.
                     42:  */
                     43:
1.4       thorpej    44: #ifndef _ALPHA_LOCK_H_
                     45: #define        _ALPHA_LOCK_H_
                     46:
1.6       thorpej    47: typedef        __volatile int          __cpu_simple_lock_t;
                     48:
1.5       thorpej    49: #define        __SIMPLELOCK_LOCKED     1
                     50: #define        __SIMPLELOCK_UNLOCKED   0
1.4       thorpej    51:
                     52: static __inline void
1.6       thorpej    53: __cpu_simple_lock_init(__cpu_simple_lock_t *alp)
1.4       thorpej    54: {
                     55:
                     56:        __asm __volatile(
1.5       thorpej    57:                "# BEGIN __cpu_simple_lock_init\n"
1.4       thorpej    58:                "       stl     $31, %0         \n"
                     59:                "       mb                      \n"
1.5       thorpej    60:                "       # END __cpu_simple_lock_init"
                     61:                : "=m" (*alp));
1.4       thorpej    62: }
                     63:
                     64: static __inline void
1.6       thorpej    65: __cpu_simple_lock(__cpu_simple_lock_t *alp)
1.4       thorpej    66: {
                     67:        unsigned long t0;
                     68:
                     69:        /*
                     70:         * Note, if we detect that the lock is held when
                     71:         * we do the initial load-locked, we spin using
                     72:         * a non-locked load to save the coherency logic
                     73:         * some work.
                     74:         */
                     75:
                     76:        __asm __volatile(
1.5       thorpej    77:                "# BEGIN __cpu_simple_lock\n"
1.4       thorpej    78:                "1:     ldl_l   %0, %3          \n"
                     79:                "       bne     %0, 2f          \n"
                     80:                "       bis     $31, %2, %0     \n"
                     81:                "       stl_c   %0, %1          \n"
                     82:                "       beq     %0, 3f          \n"
                     83:                "       mb                      \n"
                     84:                "       br      4f              \n"
                     85:                "2:     ldl     %0, %3          \n"
                     86:                "       beq     %0, 1b          \n"
                     87:                "       br      2b              \n"
                     88:                "3:     br      1b              \n"
                     89:                "4:                             \n"
1.5       thorpej    90:                "       # END __cpu_simple_lock\n"
1.16    ! thorpej    91:                : "=&r" (t0), "=m" (*alp)
        !            92:                : "i" (__SIMPLELOCK_LOCKED), "m" (*alp)
        !            93:                : "memory");
1.4       thorpej    94: }
                     95:
                     96: static __inline int
1.6       thorpej    97: __cpu_simple_lock_try(__cpu_simple_lock_t *alp)
1.4       thorpej    98: {
                     99:        unsigned long t0, v0;
                    100:
                    101:        __asm __volatile(
1.5       thorpej   102:                "# BEGIN __cpu_simple_lock_try\n"
1.4       thorpej   103:                "1:     ldl_l   %0, %4          \n"
                    104:                "       bne     %0, 2f          \n"
                    105:                "       bis     $31, %3, %0     \n"
                    106:                "       stl_c   %0, %2          \n"
                    107:                "       beq     %0, 3f          \n"
                    108:                "       mb                      \n"
                    109:                "       bis     $31, 1, %1      \n"
                    110:                "       br      4f              \n"
                    111:                "2:     bis     $31, $31, %1    \n"
                    112:                "       br      4f              \n"
                    113:                "3:     br      1b              \n"
                    114:                "4:                             \n"
1.5       thorpej   115:                "       # END __cpu_simple_lock_try"
1.16    ! thorpej   116:                : "=&r" (t0), "=r" (v0), "=m" (*alp)
        !           117:                : "i" (__SIMPLELOCK_LOCKED), "m" (*alp)
        !           118:                : "memory");
1.4       thorpej   119:
1.7       simonb    120:        return (v0 != 0);
1.4       thorpej   121: }
                    122:
                    123: static __inline void
1.6       thorpej   124: __cpu_simple_unlock(__cpu_simple_lock_t *alp)
1.4       thorpej   125: {
                    126:
                    127:        __asm __volatile(
1.5       thorpej   128:                "# BEGIN __cpu_simple_unlock\n"
1.9       thorpej   129:                "       mb                      \n"
1.4       thorpej   130:                "       stl     $31, %0         \n"
1.5       thorpej   131:                "       # END __cpu_simple_unlock"
                    132:                : "=m" (*alp));
1.4       thorpej   133: }
1.11      thorpej   134:
1.12      thorpej   135: #if defined(MULTIPROCESSOR)
1.11      thorpej   136: /*
                    137:  * On the Alpha, interprocessor interrupts come in at device priority
                    138:  * level.  This can cause some problems while waiting for r/w spinlocks
                    139:  * from a high'ish priority level: IPIs that come in will not be processed.
                    140:  * This can lead to deadlock.
                    141:  *
1.15      thorpej   142:  * This hook allows IPIs to be processed while a spinlock's interlock
1.11      thorpej   143:  * is released.
                    144:  */
1.15      thorpej   145: #define        SPINLOCK_SPIN_HOOK                                              \
1.11      thorpej   146: do {                                                                   \
                    147:        struct cpu_info *__ci = curcpu();                               \
1.15      thorpej   148:        int __s;                                                        \
1.11      thorpej   149:                                                                        \
1.13      thorpej   150:        if (__ci->ci_ipis != 0) {                                       \
                    151:                /* printf("CPU %lu has IPIs pending\n",                 \
                    152:                    __ci->ci_cpuid); */                                 \
1.15      thorpej   153:                __s = splipi();                                         \
1.13      thorpej   154:                alpha_ipi_process(__ci, NULL);                          \
1.15      thorpej   155:                splx(__s);                                              \
1.13      thorpej   156:        }                                                               \
1.11      thorpej   157: } while (0)
1.12      thorpej   158: #endif /* MULTIPROCESSOR */
1.4       thorpej   159:
                    160: #endif /* _ALPHA_LOCK_H_ */

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