1 /* $NetBSD: futex.h,v 1.7 2025/03/05 12:02:00 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2018, 2019 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell and Jason R. Thorpe. 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 /*- 33 * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved. 34 * 35 * Redistribution and use in source and binary forms, with or without 36 * modification, are permitted provided that the following conditions 37 * are met: 38 * 1. Redistributions of source code must retain the above copyright 39 * notice, this list of conditions and the following disclaimer. 40 * 2. Redistributions in binary form must reproduce the above copyright 41 * notice, this list of conditions and the following disclaimer in the 42 * documentation and/or other materials provided with the distribution. 43 * 3. All advertising materials mentioning features or use of this software 44 * must display the following acknowledgement: 45 * This product includes software developed by Emmanuel Dreyfus 46 * 4. The name of the author may not be used to endorse or promote 47 * products derived from this software without specific prior written 48 * permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS'' 51 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 52 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 53 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 54 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 55 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 56 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 57 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 58 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 59 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 60 * POSSIBILITY OF SUCH DAMAGE. 61 */ 62 63 #ifndef _SYS_FUTEX_H_ 64 #define _SYS_FUTEX_H_ 65 66 /* 67 * Definitions for the __futex(2) synchronization primitive. 68 * 69 * These definitions are intended to be ABI-compatible with the 70 * Linux futex(2) system call. 71 */ 72 73 #include <sys/timespec.h> 74 75 #define FUTEX_WAIT 0 76 #define FUTEX_WAKE 1 77 #define FUTEX_FD 2 78 #define FUTEX_REQUEUE 3 79 #define FUTEX_CMP_REQUEUE 4 80 #define FUTEX_WAKE_OP 5 81 #define FUTEX_LOCK_PI 6 82 #define FUTEX_UNLOCK_PI 7 83 #define FUTEX_TRYLOCK_PI 8 84 #define FUTEX_WAIT_BITSET 9 85 #define FUTEX_WAKE_BITSET 10 86 #define FUTEX_WAIT_REQUEUE_PI 11 87 #define FUTEX_CMP_REQUEUE_PI 12 88 89 #define FUTEX_PRIVATE_FLAG __BIT(7) 90 #define FUTEX_CLOCK_REALTIME __BIT(8) 91 92 #define FUTEX_CMD_MASK \ 93 (~(FUTEX_PRIVATE_FLAG|FUTEX_CLOCK_REALTIME)) 94 95 #define FUTEX_OP_OP_MASK __BITS(28,31) 96 #define FUTEX_OP_CMP_MASK __BITS(24,27) 97 #define FUTEX_OP_OPARG_MASK __BITS(12,23) 98 #define FUTEX_OP_CMPARG_MASK __BITS(0,11) 99 100 #define FUTEX_OP(op, oparg, cmp, cmparg) \ 101 (__SHIFTIN((op) & 0xf, FUTEX_OP_OP_MASK) |\ 102 __SHIFTIN((oparg) & 0xfff, FUTEX_OP_OPARG_MASK)|\ 103 __SHIFTIN((cmp) & 0xf, FUTEX_OP_CMP_MASK) |\ 104 __SHIFTIN((cmparg) & 0xfff, FUTEX_OP_CMPARG_MASK)) 105 106 #define FUTEX_OP_SET 0 107 #define FUTEX_OP_ADD 1 108 #define FUTEX_OP_OR 2 109 #define FUTEX_OP_ANDN 3 110 #define FUTEX_OP_XOR 4 111 #define FUTEX_OP_OPARG_SHIFT 8 112 113 #define FUTEX_OP_CMP_EQ 0 114 #define FUTEX_OP_CMP_NE 1 115 #define FUTEX_OP_CMP_LT 2 116 #define FUTEX_OP_CMP_LE 3 117 #define FUTEX_OP_CMP_GT 4 118 #define FUTEX_OP_CMP_GE 5 119 120 /* 121 * FUTEX_SYNCOBJ_0 and FUTEX_SYNCOBJ_1 are extensions to the Linux 122 * futex API that are reserved for individual consumers of futexes 123 * to define information specific to that synchronzation object. 124 * Note that as a result there is a system-wide upper limit of 125 * 268,435,455 threads (as opposed to 1,073,741,823). 126 */ 127 #define FUTEX_WAITERS ((int)__BIT(31)) 128 #define FUTEX_OWNER_DIED ((int)__BIT(30)) 129 #define FUTEX_SYNCOBJ_1 ((int)__BIT(29)) 130 #define FUTEX_SYNCOBJ_0 ((int)__BIT(28)) 131 #define FUTEX_TID_MASK ((int)__BITS(0,27)) 132 133 #define FUTEX_BITSET_MATCH_ANY ((int)__BITS(0,31)) 134 135 /* 136 * The robust futex ABI consists of an array of 3 longwords, the address 137 * of which is registered with the kernel on a per-thread basis: 138 * 139 * 0: A pointer to a singly-linked list of "lock entries". If the 140 * list is empty, this points back to the list itself. 141 * 142 * 1: An offset from address of the "lock entry" to the 32-bit futex 143 * word associated with that lock entry (may be negative). 144 * 145 * 2: A "pending" pointer, for locks that are in the process of being 146 * acquired or released. 147 * 148 * PI futexes are handled slightly differently. User-space indicates 149 * an entry is for a PI futex by setting the last-significant bit. 150 */ 151 #define _FUTEX_ROBUST_HEAD_LIST 0 152 #define _FUTEX_ROBUST_HEAD_OFFSET 1 153 #define _FUTEX_ROBUST_HEAD_PENDING 2 154 #define _FUTEX_ROBUST_HEAD_NWORDS 3 155 #define _FUTEX_ROBUST_HEAD_SIZE (_FUTEX_ROBUST_HEAD_NWORDS * \ 156 sizeof(u_long)) 157 #define _FUTEX_ROBUST_HEAD_SIZE32 (_FUTEX_ROBUST_HEAD_NWORDS * \ 158 sizeof(uint32_t)) 159 #define _FUTEX_ROBUST_ENTRY_PI __BIT(0) 160 161 #ifdef __LIBC_FUTEX_PRIVATE 162 struct futex_robust_list { 163 struct futex_robust_list *next; 164 }; 165 166 struct futex_robust_list_head { 167 struct futex_robust_list list; 168 long futex_offset; 169 struct futex_robust_list *pending_list; 170 }; 171 #endif /* __LIBC_FUTEX_PRIVATE */ 172 173 #ifdef _KERNEL 174 struct lwp; 175 176 int futex_robust_head_lookup(struct lwp *, lwpid_t, void **); 177 void futex_release_all_lwp(struct lwp *); 178 int do_futex(int *, int, int, const struct timespec *, int *, int, 179 int, register_t *); 180 void futex_sys_init(void); 181 void futex_sys_fini(void); 182 #endif /* _KERNEL */ 183 184 #endif /* ! _SYS_FUTEX_H_ */ 185