1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/* $OpenBSD: mutex.h,v 1.18 2019/04/23 13:35:12 visa Exp $ */
/*
* Copyright (c) 2004 Artur Grabowski <art@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef _SYS_MUTEX_H_
#define _SYS_MUTEX_H_
/*
* A mutex is:
* - owned by a cpu.
* - non-recursive.
* - spinning.
* - not providing mutual exclusion between processes, only cpus.
* - providing interrupt blocking when necessary.
*
* Different mutexes can be nested, but not interleaved. This is ok:
* "mtx_enter(foo); mtx_enter(bar); mtx_leave(bar); mtx_leave(foo);"
* This is _not_ ok:
* "mtx_enter(foo); mtx_enter(bar); mtx_leave(foo); mtx_leave(bar);"
*/
#include <machine/mutex.h>
#ifdef __USE_MI_MUTEX
#include <sys/_lock.h>
struct mutex {
volatile void *mtx_owner;
int mtx_wantipl;
int mtx_oldipl;
#ifdef WITNESS
struct lock_object mtx_lock_obj;
#endif
};
/*
* To prevent lock ordering problems with the kernel lock, we need to
* make sure we block all interrupts that can grab the kernel lock.
* The simplest way to achieve this is to make sure mutexes always
* raise the interrupt priority level to the highest level that has
* interrupts that grab the kernel lock.
*/
#ifdef MULTIPROCESSOR
#define __MUTEX_IPL(ipl) \
(((ipl) > IPL_NONE && (ipl) < IPL_MPFLOOR) ? IPL_MPFLOOR : (ipl))
#else
#define __MUTEX_IPL(ipl) (ipl)
#endif
#ifdef WITNESS
#define MUTEX_INITIALIZER_FLAGS(ipl, name, flags) \
{ NULL, __MUTEX_IPL((ipl)), IPL_NONE, MTX_LO_INITIALIZER(name, flags) }
#else
#define MUTEX_INITIALIZER_FLAGS(ipl, name, flags) \
{ NULL, __MUTEX_IPL((ipl)), IPL_NONE }
#endif
void __mtx_init(struct mutex *, int);
#define _mtx_init(mtx, ipl) __mtx_init((mtx), __MUTEX_IPL((ipl)))
#ifdef DIAGNOSTIC
#define MUTEX_ASSERT_LOCKED(mtx) do { \
if (((mtx)->mtx_owner != curcpu()) && !(panicstr || db_active)) \
panic("mutex %p not held in %s", (mtx), __func__); \
} while (0)
#define MUTEX_ASSERT_UNLOCKED(mtx) do { \
if (((mtx)->mtx_owner == curcpu()) && !(panicstr || db_active)) \
panic("mutex %p held in %s", (mtx), __func__); \
} while (0)
#else
#define MUTEX_ASSERT_LOCKED(mtx) do { } while (0)
#define MUTEX_ASSERT_UNLOCKED(mtx) do { } while (0)
#endif
#define MUTEX_LOCK_OBJECT(mtx) (&(mtx)->mtx_lock_obj)
#define MUTEX_OLDIPL(mtx) (mtx)->mtx_oldipl
#endif /* __USE_MI_MUTEX */
#define MTX_LO_FLAGS(flags) \
((!((flags) & MTX_NOWITNESS) ? LO_WITNESS : 0) | \
((flags) & MTX_DUPOK ? LO_DUPOK : 0) | \
LO_INITIALIZED | (LO_CLASS_MUTEX << LO_CLASSSHIFT))
#define __MTX_STRING(x) #x
#define __MTX_S(x) __MTX_STRING(x)
#define __MTX_NAME __FILE__ ":" __MTX_S(__LINE__)
#define MTX_LO_INITIALIZER(name, flags) \
{ .lo_type = &(const struct lock_type){ .lt_name = __MTX_NAME }, \
.lo_name = (name), \
.lo_flags = MTX_LO_FLAGS(flags) }
#define MTX_NOWITNESS 0x01
#define MTX_DUPOK 0x02
#define MUTEX_INITIALIZER(ipl) \
MUTEX_INITIALIZER_FLAGS(ipl, __MTX_NAME, 0)
/*
* Some architectures need to do magic for the ipl, so they need a macro.
*/
#ifndef _mtx_init
void _mtx_init(struct mutex *, int);
#endif
void mtx_enter(struct mutex *);
int mtx_enter_try(struct mutex *);
void mtx_leave(struct mutex *);
#define mtx_init(m, ipl) mtx_init_flags(m, ipl, NULL, 0)
#ifdef WITNESS
void _mtx_init_flags(struct mutex *, int, const char *, int,
const struct lock_type *);
#define mtx_init_flags(m, ipl, name, flags) do { \
static const struct lock_type __lock_type = { .lt_name = #m }; \
_mtx_init_flags(m, ipl, name, flags, &__lock_type); \
} while (0)
#else /* WITNESS */
#define mtx_init_flags(m, ipl, name, flags) do { \
(void)(name); (void)(flags); \
_mtx_init(m, ipl); \
} while (0)
#define _mtx_init_flags(m,i,n,f,t) _mtx_init(m,i)
#endif /* WITNESS */
#if defined(_KERNEL) && defined(DDB)
struct db_mutex {
struct cpu_info *mtx_owner;
unsigned long mtx_intr_state;
};
#define DB_MUTEX_INITIALIZER { NULL, 0 }
void db_mtx_enter(struct db_mutex *);
void db_mtx_leave(struct db_mutex *);
#endif /* _KERNEL && DDB */
#endif
|
