1 /* $NetBSD: mutex.h,v 1.7 2024/11/25 22:04:14 skrll 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 #include <sys/types.h> 36 37 #ifndef __MUTEX_PRIVATE 38 39 struct kmutex { 40 uintptr_t mtx_pad1; 41 }; 42 43 #else /* __MUTEX_PRIVATE */ 44 45 #include <sys/cdefs.h> 46 47 #include <sys/param.h> 48 49 #include <machine/intr.h> 50 51 struct kmutex { 52 volatile uintptr_t mtx_owner; 53 }; 54 55 #ifdef _KERNEL 56 57 #ifdef _LP64 58 #define MTX_ASMOP_SFX ".d" // doubleword atomic op 59 #else 60 #define MTX_ASMOP_SFX ".w" // word atomic op 61 #endif 62 63 #define MTX_LOCK __BIT(8) // just one bit 64 #define MTX_IPL __BITS(7,4) // only need 4 bits 65 66 #undef MUTEX_SPIN_IPL // override <sys/mutex.h> 67 #define MUTEX_SPIN_IPL(a) riscv_mutex_spin_ipl(a) 68 #define MUTEX_INITIALIZE_SPIN_IPL(a,b) riscv_mutex_initialize_spin_ipl(a,b) 69 #define MUTEX_SPINBIT_LOCK_INIT(a) riscv_mutex_spinbit_lock_init(a) 70 #define MUTEX_SPINBIT_LOCK_TRY(a) riscv_mutex_spinbit_lock_try(a) 71 #define MUTEX_SPINBIT_LOCKED_P(a) riscv_mutex_spinbit_locked_p(a) 72 #define MUTEX_SPINBIT_LOCK_UNLOCK(a) riscv_mutex_spinbit_lock_unlock(a) 73 74 static inline ipl_cookie_t 75 riscv_mutex_spin_ipl(kmutex_t *__mtx) 76 { 77 return (ipl_cookie_t){._spl = __SHIFTOUT(__mtx->mtx_owner, MTX_IPL)}; 78 } 79 80 static inline void 81 riscv_mutex_initialize_spin_ipl(kmutex_t *__mtx, int ipl) 82 { 83 __mtx->mtx_owner = (__mtx->mtx_owner & ~MTX_IPL) 84 | __SHIFTIN(ipl, MTX_IPL); 85 } 86 87 static inline void 88 riscv_mutex_spinbit_lock_init(kmutex_t *__mtx) 89 { 90 __mtx->mtx_owner &= ~MTX_LOCK; 91 } 92 93 static inline bool 94 riscv_mutex_spinbit_locked_p(const kmutex_t *__mtx) 95 { 96 return (__mtx->mtx_owner & MTX_LOCK) != 0; 97 } 98 99 static inline bool 100 riscv_mutex_spinbit_lock_try(kmutex_t *__mtx) 101 { 102 uintptr_t __old; 103 __asm __volatile( 104 "amoor" MTX_ASMOP_SFX ".aq\t%0, %1, (%2)" 105 : "=r"(__old) 106 : "r"(MTX_LOCK), "r"(__mtx)); 107 return (__old & MTX_LOCK) == 0; 108 } 109 110 static inline void 111 riscv_mutex_spinbit_lock_unlock(kmutex_t *__mtx) 112 { 113 __asm __volatile( 114 "amoand" MTX_ASMOP_SFX ".rl\tx0, %0, (%1)" 115 :: "r"(~MTX_LOCK), "r"(__mtx)); 116 } 117 118 #endif /* _KERNEL */ 119 120 #if 0 121 #define __HAVE_MUTEX_STUBS 1 122 #define __HAVE_SPIN_MUTEX_STUBS 1 123 #endif 124 #define __HAVE_SIMPLE_MUTEXES 1 125 126 #endif /* __MUTEX_PRIVATE */ 127 128 #endif /* _RISCV_MUTEX_H_ */ 129