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      1 /*	$NetBSD: lock.h,v 1.34 2022/02/13 13:42:21 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2000 Ludd, University of Lule}, Sweden.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #ifndef _VAX_LOCK_H_
     29 #define _VAX_LOCK_H_
     30 
     31 #include <sys/param.h>
     32 
     33 #ifdef _KERNEL
     34 #ifdef _KERNEL_OPT
     35 #include "opt_multiprocessor.h"
     36 #include <machine/intr.h>
     37 #endif
     38 #include <machine/cpu.h>
     39 #endif
     40 
     41 static __inline int
     42 __SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
     43 {
     44 	return *__ptr == __SIMPLELOCK_LOCKED;
     45 }
     46 
     47 static __inline int
     48 __SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
     49 {
     50 	return *__ptr == __SIMPLELOCK_UNLOCKED;
     51 }
     52 
     53 static __inline void
     54 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
     55 {
     56 	*__ptr = __SIMPLELOCK_UNLOCKED;
     57 }
     58 
     59 static __inline void
     60 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
     61 {
     62 	*__ptr = __SIMPLELOCK_LOCKED;
     63 }
     64 
     65 static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *);
     66 static __inline void
     67 __cpu_simple_lock_init(__cpu_simple_lock_t *__alp)
     68 {
     69 	*__alp = __SIMPLELOCK_UNLOCKED;
     70 }
     71 
     72 static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *);
     73 static __inline int
     74 __cpu_simple_lock_try(__cpu_simple_lock_t *__alp)
     75 {
     76 	int ret;
     77 
     78 #ifdef _HARDKERNEL
     79 	__asm __volatile ("movl %1,%%r1;jsb Slocktry;movl %%r0,%0"
     80 		: "=&r"(ret)
     81 		: "g"(__alp)
     82 		: "r0","r1","cc","memory");
     83 #else
     84 	__asm __volatile ("clrl %0;bbssi $0,%1,1f;incl %0;1:"
     85 		: "=&r"(ret)
     86 		: "m"(*__alp)
     87 		: "cc", "memory");
     88 #endif
     89 
     90 	return ret;
     91 }
     92 
     93 static __inline void __cpu_simple_lock(__cpu_simple_lock_t *);
     94 static __inline void
     95 __cpu_simple_lock(__cpu_simple_lock_t *__alp)
     96 {
     97 #if defined(_HARDKERNEL) && defined(MULTIPROCESSOR)
     98 	struct cpu_info * const __ci = curcpu();
     99 
    100 	while (__cpu_simple_lock_try(__alp) == 0) {
    101 #define	VAX_LOCK_CHECKS ((1 << IPI_SEND_CNCHAR) | (1 << IPI_DDB))
    102 		if (__ci->ci_ipimsgs & VAX_LOCK_CHECKS) {
    103 			cpu_handle_ipi();
    104 		}
    105 	}
    106 #else /* _HARDKERNEL && MULTIPROCESSOR */
    107 	__asm __volatile ("1:bbssi $0,%0,1b"
    108 		: /* No outputs */
    109 		: "m"(*__alp)
    110 		: "cc", "memory");
    111 #endif /* _HARDKERNEL && MULTIPROCESSOR */
    112 }
    113 
    114 static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *);
    115 static __inline void
    116 __cpu_simple_unlock(__cpu_simple_lock_t *__alp)
    117 {
    118 #ifdef _HARDKERNEL
    119 	__asm __volatile ("movl %0,%%r1;jsb Sunlock"
    120 		: /* No output */
    121 		: "g"(__alp)
    122 		: "r1","cc","memory");
    123 #else
    124 	__asm __volatile ("bbcci $0,%0,1f;1:"
    125 		: /* No output */
    126 		: "m"(*__alp)
    127 		: "cc", "memory");
    128 #endif
    129 }
    130 
    131 #if defined(MULTIPROCESSOR)
    132 /*
    133  * On the Vax, interprocessor interrupts can come in at device priority
    134  * level or lower. This can cause some problems while waiting for r/w
    135  * spinlocks from a high'ish priority level: IPIs that come in will not
    136  * be processed. This can lead to deadlock.
    137  *
    138  * This hook allows IPIs to be processed while a spinlock's interlock
    139  * is released.
    140  */
    141 #define SPINLOCK_SPIN_HOOK						\
    142 do {									\
    143 	struct cpu_info * const __ci = curcpu();			\
    144 									\
    145 	if (__ci->ci_ipimsgs != 0) {					\
    146 		/* printf("CPU %lu has IPIs pending\n",			\
    147 		    __ci->ci_cpuid); */					\
    148 		cpu_handle_ipi();					\
    149 	}								\
    150 } while (/*CONSTCOND*/0)
    151 #endif /* MULTIPROCESSOR */
    152 
    153 #endif /* _VAX_LOCK_H_ */
    154