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lock.h revision 1.1 
      1 /* $NetBSD: lock.h,v 1.1 2014/09/19 17:36:26 matt Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matt Thomas of 3am Software Foundry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 /*
     32  * Machine-dependent spin lock operations.
     33  */
     34 
     35 #ifndef _RISCV_LOCK_H_
     36 #define	_RISCV_LOCK_H_
     37 
     38 static __inline int
     39 __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
     40 {
     41 	return *__ptr != __SIMPLELOCK_UNLOCKED;
     42 }
     43 
     44 static __inline int
     45 __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
     46 {
     47 	return *__ptr == __SIMPLELOCK_UNLOCKED;
     48 }
     49 
     50 static __inline void
     51 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
     52 {
     53 #if 0
     54 	__atomic_clear(__ptr, __ATOMIC_RELAXED);
     55 #else
     56 	*__ptr = __SIMPLELOCK_UNLOCKED;
     57 #endif
     58 }
     59 
     60 static __inline void
     61 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
     62 {
     63 #if 0
     64 	(void)__atomic_test_and_set(__ptr, __ATOMIC_RELAXED);
     65 #else
     66 	*__ptr = __SIMPLELOCK_LOCKED;
     67 #endif
     68 }
     69 
     70 static __inline void __unused
     71 __cpu_simple_lock_init(__cpu_simple_lock_t *__ptr)
     72 {
     73 #if 0
     74 	__atomic_clear(__ptr, __ATOMIC_RELAXED);
     75 #else
     76 	*__ptr = __SIMPLELOCK_UNLOCKED;
     77 #endif
     78 }
     79 
     80 static __inline void __unused
     81 __cpu_simple_lock(__cpu_simple_lock_t *__ptr)
     82 {
     83 #if 0
     84 	while (__atomic_test_and_set(__ptr, __ATOMIC_ACQUIRE)) {
     85 		/* do nothing */
     86 	}
     87 #else
     88 	int __tmp;
     89 	__asm(
     90 	"\n"	"1:"
     91 	"\n\t"	"amoswap.w.aq	%[__tmp], %[__newval], 0(%[__ptr])"
     92 	"\n\t"	"bnez		%[__tmp], 1b"
     93 	   :	[__tmp] "=&r" (__tmp)
     94 	   :	[__newval] "r" (__SIMPLELOCK_LOCKED),
     95 		[__ptr] "r" (__ptr));
     96 #endif
     97 }
     98 
     99 static __inline int __unused
    100 __cpu_simple_lock_try(__cpu_simple_lock_t *__ptr)
    101 {
    102 #if 0
    103 	return !__atomic_test_and_set(__ptr, __ATOMIC_ACQUIRE);
    104 #else
    105 	int __oldval;
    106 	__asm(	"amoswap.w.aq\t%[__oldval], %[__newval], 0(%[__ptr])"
    107 	   :	[__oldval] "=r" (__oldval)
    108 	   :	[__newval] "r" (__SIMPLELOCK_LOCKED),
    109 		[__ptr] "r" (__ptr));
    110 	return __oldval == __SIMPLELOCK_UNLOCKED;
    111 #endif
    112 }
    113 
    114 static __inline void __unused
    115 __cpu_simple_unlock(__cpu_simple_lock_t *__ptr)
    116 {
    117 #if 0
    118 	__atomic_clear(__ptr, __ATOMIC_RELEASE);
    119 #else
    120 	__asm("amoswap.w.rl\tx0, x0, 0(%[__ptr])" :: [__ptr] "r" (__ptr));
    121 #endif
    122 }
    123 
    124 #endif /* _RISCV_LOCK_H_ */
    125