1 /* $NetBSD: mutex.h,v 1.3 2019/11/29 22:55:34 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe and Andrew Doran. 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 #ifndef _RISCV_MUTEX_H_ 33 #define _RISCV_MUTEX_H_ 34 35 #ifndef __MUTEX_PRIVATE 36 37 struct kmutex { 38 uintptr_t mtx_pad1; 39 }; 40 41 #else /* __MUTEX_PRIVATE */ 42 43 #include <sys/param.h> 44 45 struct kmutex { 46 volatile uintptr_t mtx_owner; 47 }; 48 49 #ifdef _LP64 50 #define MTX_ASMOP_SFX ".d" // doubleword atomic op 51 #else 52 #define MTX_ASMOP_SFX ".w" // word atomic op 53 #endif 54 55 #define MTX_LOCK __BIT(8) // just one bit 56 #define MTX_IPL __BITS(7,4) // only need 4 bits 57 58 #undef MUTEX_SPIN_IPL // override <sys/mutex.h> 59 #define MUTEX_SPIN_IPL(a) riscv_mutex_spin_ipl(a) 60 #define MUTEX_INITIALIZE_SPIN_IPL(a,b) riscv_mutex_initialize_spin_ipl(a,b) 61 #define MUTEX_SPINBIT_LOCK_INIT(a) riscv_mutex_spinbit_lock_init(a) 62 #define MUTEX_SPINBIT_LOCK_TRY(a) riscv_mutex_spinbit_lock_try(a) 63 #define MUTEX_SPINBIT_LOCKED_P(a) riscv_mutex_spinbit_locked_p(a) 64 #define MUTEX_SPINBIT_LOCK_UNLOCK(a) riscv_mutex_spinbit_lock_unlock(a) 65 66 static inline ipl_cookie_t 67 riscv_mutex_spin_ipl(kmutex_t *__mtx) 68 { 69 return (ipl_cookie_t){._spl = __SHIFTOUT(__mtx->mtx_owner, MTX_IPL)}; 70 } 71 72 static inline void 73 riscv_mutex_initialize_spin_ipl(kmutex_t *__mtx, int ipl) 74 { 75 __mtx->mtx_owner = (__mtx->mtx_owner & ~MTX_IPL) 76 | __SHIFTIN(ipl, MTX_IPL); 77 } 78 79 static inline void 80 riscv_mutex_spinbit_lock_init(kmutex_t *__mtx) 81 { 82 __mtx->mtx_owner &= ~MTX_LOCK; 83 } 84 85 static inline bool 86 riscv_mutex_spinbit_locked_p(const kmutex_t *__mtx) 87 { 88 return (__mtx->mtx_owner & MTX_LOCK) != 0; 89 } 90 91 static inline bool 92 riscv_mutex_spinbit_lock_try(kmutex_t *__mtx) 93 { 94 uintptr_t __old; 95 __asm __volatile( 96 "amoor" MTX_ASMOP_SFX ".aq\t%0, %1, (%2)" 97 : "=r"(__old) 98 : "r"(MTX_LOCK), "r"(__mtx)); 99 return (__old & MTX_LOCK) == 0; 100 } 101 102 static inline void 103 riscv_mutex_spinbit_lock_unlock(kmutex_t *__mtx) 104 { 105 __asm __volatile( 106 "amoand" MTX_ASMOP_SFX ".rl\tx0, %0, (%1)" 107 :: "r"(~MTX_LOCK), "r"(__mtx)); 108 } 109 110 #if 0 111 #define __HAVE_MUTEX_STUBS 1 112 #define __HAVE_SPIN_MUTEX_STUBS 1 113 #endif 114 #define __HAVE_SIMPLE_MUTEXES 1 115 116 #define MUTEX_CAS(p, o, n) \ 117 (atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) 118 119 #endif /* __MUTEX_PRIVATE */ 120 121 #endif /* _RISCV_MUTEX_H_ */ 122