1 /* $OpenBSD: mutex.h,v 1.9 2018/01/13 15:18:11 mpi Exp $ */ 2 3 /* 4 * Copyright (c) 2004 Artur Grabowski <art@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 19 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef _MACHINE_MUTEX_H_ 29 #define _MACHINE_MUTEX_H_ 30 31 #include <sys/_lock.h> 32 33 #define MUTEX_UNLOCKED { 1, 1, 1, 1 } 34 35 /* Note: mtx_lock must be 16-byte aligned. */ 36 struct mutex { 37 #ifdef MULTIPROCESSOR 38 volatile int mtx_lock[4]; 39 #endif 40 int mtx_wantipl; 41 int mtx_oldipl; 42 volatile void *mtx_owner; 43 #ifdef WITNESS 44 struct lock_object mtx_lock_obj; 45 #endif 46 }; 47 48 /* 49 * To prevent lock ordering problems with the kernel lock, we need to 50 * make sure we block all interrupts that can grab the kernel lock. 51 * The simplest way to achieve this is to make sure mutexes always 52 * raise the interrupt priority level to the highest level that has 53 * interrupts that grab the kernel lock. 54 */ 55 #ifdef MULTIPROCESSOR 56 #define __MUTEX_IPL(ipl) \ 57 (((ipl) > IPL_NONE && (ipl) < IPL_MPFLOOR) ? IPL_MPFLOOR : (ipl)) 58 #ifdef WITNESS 59 #define MUTEX_INITIALIZER_FLAGS(ipl, name, flags) \ 60 { MUTEX_UNLOCKED, __MUTEX_IPL((ipl)), 0, NULL, \ 61 MTX_LO_INITIALIZER(name, flags) } 62 #else /* WITNESS */ 63 #define MUTEX_INITIALIZER_FLAGS(ipl, name, flags) \ 64 { MUTEX_UNLOCKED, __MUTEX_IPL((ipl)), 0, NULL } 65 #endif /* WITNESS */ 66 #else /* MULTIPROCESSOR */ 67 #define __MUTEX_IPL(ipl) (ipl) 68 #define MUTEX_INITIALIZER_FLAGS(ipl, name, flags) \ 69 { __MUTEX_IPL((ipl)), 0, NULL } 70 #endif /* MULTIPROCESSOR */ 71 72 void __mtx_init(struct mutex *, int); 73 #define _mtx_init(mtx, ipl) __mtx_init((mtx), __MUTEX_IPL((ipl))) 74 75 #ifdef DIAGNOSTIC 76 #define MUTEX_ASSERT_LOCKED(mtx) do { \ 77 if ((mtx)->mtx_owner != curcpu()) \ 78 panic("mutex %p not held in %s", (mtx), __func__); \ 79 } while (0) 80 81 #define MUTEX_ASSERT_UNLOCKED(mtx) do { \ 82 if ((mtx)->mtx_owner == curcpu()) \ 83 panic("mutex %p held in %s", (mtx), __func__); \ 84 } while (0) 85 #else 86 #define MUTEX_ASSERT_LOCKED(mtx) do { } while (0) 87 #define MUTEX_ASSERT_UNLOCKED(mtx) do { } while (0) 88 #endif 89 90 #define MUTEX_LOCK_OBJECT(mtx) (&(mtx)->mtx_lock_obj) 91 #define MUTEX_OLDIPL(mtx) (mtx)->mtx_oldipl 92 93 #endif 94