1 /* $NetBSD: mutex.h,v 1.19 2023/07/13 07:46:43 mrg 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 _HPPA_MUTEX_H_
33 #define _HPPA_MUTEX_H_
34
35 /*
36 * The HPPA mutex implementation is troublesome, because HPPA lacks
37 * a compare-and-set operation, yet there are many SMP HPPA machines
38 * in circulation. SMP for spin mutexes is easy - we don't need to
39 * know who owns the lock. For adaptive mutexes, we need an owner
40 * field and additional interlock
41 */
42
43 #ifndef __ASSEMBLER__
44
45 #include <sys/types.h>
46
47 #ifdef __MUTEX_PRIVATE
48 #include <machine/lock.h>
49 #include <machine/intr.h>
50 #endif
51
52 struct kmutex {
53 union {
54 /*
55 * Only the 16 bytes aligned word of __cpu_simple_lock_t will
56 * be used. It's 16 bytes to simplify the allocation.
57 * See hppa/lock.h
58 */
59 #ifdef __MUTEX_PRIVATE
60 struct {
61 __cpu_simple_lock_t mtxu_lock; /* 0-15 */
62 volatile uint32_t mtxs_owner; /* 16-19 */
63 ipl_cookie_t mtxs_ipl; /* 20-23 */
64 volatile uint8_t mtxs_waiters; /* 24 */
65
66 /* For LOCKDEBUG */
67 uint8_t mtxs_dodebug; /* 25 */
68 } s;
69 #endif
70 uint8_t mtxu_pad[32]; /* 0 - 32 */
71 } u;
72 } __aligned (16);
73 #endif
74
75 #ifdef __MUTEX_PRIVATE
76
77 #define __HAVE_MUTEX_STUBS 1
78
79 #define mtx_lock u.s.mtxu_lock
80 #define mtx_owner u.s.mtxs_owner
81 #define mtx_ipl u.s.mtxs_ipl
82 #define mtx_waiters u.s.mtxs_waiters
83 #define mtx_dodebug u.s.mtxs_dodebug
84
85 /* Magic constants for mtx_owner */
86 #define MUTEX_ADAPTIVE_UNOWNED 0xffffff00
87 #define MUTEX_SPIN_FLAG 0xffffff10
88 #define MUTEX_UNOWNED_OR_SPIN(x) (((x) & 0xffffffef) == 0xffffff00)
89
90 #if !defined(__ASSEMBLER__) && defined(_KERNEL)
91
92 static inline uintptr_t
MUTEX_OWNER(uintptr_t owner)93 MUTEX_OWNER(uintptr_t owner)
94 {
95 return owner;
96 }
97
98 static inline int
MUTEX_OWNED(uintptr_t owner)99 MUTEX_OWNED(uintptr_t owner)
100 {
101 return owner != MUTEX_ADAPTIVE_UNOWNED;
102 }
103
104 static inline int
MUTEX_SET_WAITERS(struct kmutex * mtx,uintptr_t owner)105 MUTEX_SET_WAITERS(struct kmutex *mtx, uintptr_t owner)
106 {
107 __sync(); /* formerly mb_read */
108 mtx->mtx_waiters = 1;
109 __sync(); /* formerly mb_memory */
110 return mtx->mtx_owner != MUTEX_ADAPTIVE_UNOWNED;
111 }
112
113 static inline int
MUTEX_HAS_WAITERS(const volatile struct kmutex * mtx)114 MUTEX_HAS_WAITERS(const volatile struct kmutex *mtx)
115 {
116 return mtx->mtx_waiters != 0;
117 }
118
119 static inline void
MUTEX_INITIALIZE_SPIN(struct kmutex * mtx,bool dodebug,int ipl)120 MUTEX_INITIALIZE_SPIN(struct kmutex *mtx, bool dodebug, int ipl)
121 {
122 mtx->mtx_ipl = makeiplcookie(ipl);
123 mtx->mtx_dodebug = dodebug;
124 mtx->mtx_owner = MUTEX_SPIN_FLAG;
125 __cpu_simple_lock_init(&mtx->mtx_lock);
126 }
127
128 static inline void
MUTEX_INITIALIZE_ADAPTIVE(struct kmutex * mtx,bool dodebug)129 MUTEX_INITIALIZE_ADAPTIVE(struct kmutex *mtx, bool dodebug)
130 {
131 mtx->mtx_dodebug = dodebug;
132 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED;
133 __cpu_simple_lock_init(&mtx->mtx_lock);
134 }
135
136 static inline void
MUTEX_DESTROY(struct kmutex * mtx)137 MUTEX_DESTROY(struct kmutex *mtx)
138 {
139 mtx->mtx_owner = 0xffffffff;
140 }
141
142 static inline bool
MUTEX_DEBUG_P(const volatile struct kmutex * mtx)143 MUTEX_DEBUG_P(const volatile struct kmutex *mtx)
144 {
145 return mtx->mtx_dodebug != 0;
146 }
147
148 static inline int
MUTEX_SPIN_P(const uintptr_t owner)149 MUTEX_SPIN_P(const uintptr_t owner)
150 {
151 return owner == MUTEX_SPIN_FLAG;
152 }
153
154 static inline int
MUTEX_ADAPTIVE_P(const uintptr_t owner)155 MUTEX_ADAPTIVE_P(const uintptr_t owner)
156 {
157 return owner != MUTEX_SPIN_FLAG;
158 }
159
160 /* Acquire an adaptive mutex */
161 static inline int
MUTEX_ACQUIRE(struct kmutex * mtx,uintptr_t curthread)162 MUTEX_ACQUIRE(struct kmutex *mtx, uintptr_t curthread)
163 {
164 if (!__cpu_simple_lock_try(&mtx->mtx_lock))
165 return 0;
166 mtx->mtx_owner = curthread;
167 return 1;
168 }
169
170 /* Release an adaptive mutex */
171 static inline void
MUTEX_RELEASE(struct kmutex * mtx)172 MUTEX_RELEASE(struct kmutex *mtx)
173 {
174 mtx->mtx_owner = MUTEX_ADAPTIVE_UNOWNED;
175 __cpu_simple_unlock(&mtx->mtx_lock);
176 mtx->mtx_waiters = 0;
177 }
178
179 static inline void
MUTEX_CLEAR_WAITERS(struct kmutex * mtx)180 MUTEX_CLEAR_WAITERS(struct kmutex *mtx)
181 {
182 mtx->mtx_waiters = 0;
183 }
184
185 #endif /* !__ASSEMBLER__ && _KERNEL */
186
187 #endif /* __MUTEX_PRIVATE */
188
189 #endif /* _HPPA_MUTEX_H_ */
190