1 /* 2 * Copyright 2010-2015 Samy Al Bahra. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #ifndef CK_SPINLOCK_FAS_H 28 #define CK_SPINLOCK_FAS_H 29 30 #include <ck_backoff.h> 31 #include <ck_cc.h> 32 #include <ck_elide.h> 33 #include <ck_pr.h> 34 #include <ck_stdbool.h> 35 36 #ifndef CK_F_SPINLOCK_FAS 37 #define CK_F_SPINLOCK_FAS 38 39 struct ck_spinlock_fas { 40 unsigned int value; 41 }; 42 typedef struct ck_spinlock_fas ck_spinlock_fas_t; 43 44 #define CK_SPINLOCK_FAS_INITIALIZER {false} 45 46 CK_CC_INLINE static void 47 ck_spinlock_fas_init(struct ck_spinlock_fas *lock) 48 { 49 50 lock->value = false; 51 ck_pr_barrier(); 52 return; 53 } 54 55 CK_CC_INLINE static bool 56 ck_spinlock_fas_trylock(struct ck_spinlock_fas *lock) 57 { 58 bool value; 59 60 value = ck_pr_fas_uint(&lock->value, true); 61 ck_pr_fence_lock(); 62 63 return !value; 64 } 65 66 CK_CC_INLINE static bool 67 ck_spinlock_fas_locked(struct ck_spinlock_fas *lock) 68 { 69 bool r; 70 71 r = ck_pr_load_uint(&lock->value); 72 ck_pr_fence_acquire(); 73 return r; 74 } 75 76 CK_CC_INLINE static void 77 ck_spinlock_fas_lock(struct ck_spinlock_fas *lock) 78 { 79 80 while (CK_CC_UNLIKELY(ck_pr_fas_uint(&lock->value, true) == true)) { 81 do { 82 ck_pr_stall(); 83 } while (ck_pr_load_uint(&lock->value) == true); 84 } 85 86 ck_pr_fence_lock(); 87 return; 88 } 89 90 CK_CC_INLINE static void 91 ck_spinlock_fas_lock_eb(struct ck_spinlock_fas *lock) 92 { 93 ck_backoff_t backoff = CK_BACKOFF_INITIALIZER; 94 95 while (ck_pr_fas_uint(&lock->value, true) == true) 96 ck_backoff_eb(&backoff); 97 98 ck_pr_fence_lock(); 99 return; 100 } 101 102 CK_CC_INLINE static void 103 ck_spinlock_fas_unlock(struct ck_spinlock_fas *lock) 104 { 105 106 ck_pr_fence_unlock(); 107 ck_pr_store_uint(&lock->value, false); 108 return; 109 } 110 111 CK_ELIDE_PROTOTYPE(ck_spinlock_fas, ck_spinlock_fas_t, 112 ck_spinlock_fas_locked, ck_spinlock_fas_lock, 113 ck_spinlock_fas_locked, ck_spinlock_fas_unlock) 114 115 CK_ELIDE_TRYLOCK_PROTOTYPE(ck_spinlock_fas, ck_spinlock_fas_t, 116 ck_spinlock_fas_locked, ck_spinlock_fas_trylock) 117 118 #endif /* CK_F_SPINLOCK_FAS */ 119 #endif /* CK_SPINLOCK_FAS_H */ 120