xref: /illumos-gate/usr/src/lib/libfakekernel/common/sys/mutex.h (revision dd72704bd9e794056c558153663c739e2012d721)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
24  * Copyright 2017 RackTop Systems.
25  */
26 
27 #ifndef _SYS_MUTEX_H
28 #define	_SYS_MUTEX_H
29 
30 #include <sys/synch.h>	/* lwp_mutex_t */
31 
32 #ifdef	__cplusplus
33 extern "C" {
34 #endif
35 
36 /*
37  * Public interface to mutual exclusion locks.  See mutex(9F) for details.
38  *
39  * The basic mutex type is MUTEX_ADAPTIVE, which is expected to be used
40  * in almost all of the kernel.  MUTEX_SPIN provides interrupt blocking
41  * and must be used in interrupt handlers above LOCK_LEVEL.  The iblock
42  * cookie argument to mutex_init() encodes the interrupt level to block.
43  * The iblock cookie must be NULL for adaptive locks.
44  *
45  * MUTEX_DEFAULT is the type usually specified (except in drivers) to
46  * mutex_init().  It is identical to MUTEX_ADAPTIVE.
47  *
48  * MUTEX_DRIVER is always used by drivers.  mutex_init() converts this to
49  * either MUTEX_ADAPTIVE or MUTEX_SPIN depending on the iblock cookie.
50  *
51  * Mutex statistics can be gathered on the fly, without rebooting or
52  * recompiling the kernel, via the lockstat driver (lockstat(4D)).
53  */
54 typedef enum {
55 	MUTEX_ADAPTIVE = 0,	/* spin if owner is running, otherwise block */
56 	MUTEX_SPIN = 1,		/* block interrupts and spin */
57 	MUTEX_DRIVER = 4,	/* driver (DDI) mutex */
58 	MUTEX_DEFAULT = 6	/* kernel default mutex */
59 } kmutex_type_t;
60 
61 struct _kmutex {
62 	lwp_mutex_t m_lock;
63 	void *m_owner;
64 };
65 typedef struct _kmutex kmutex_t;
66 
67 #if defined(_KERNEL) || defined(_FAKE_KERNEL)
68 /* See the real sys/mutex.h */
69 typedef struct pad_mutex {
70 	kmutex_t	pad_mutex;
71 #ifdef _LP64
72 	char		pad_pad[64 - sizeof (kmutex_t)];
73 #endif
74 } pad_mutex_t;
75 #endif	/* _KERNEL */
76 
77 extern char *volatile panicstr;  /* panic string pointer */
78 
79 #define	MUTEX_HELD(x)		(mutex_owned(x))
80 #define	MUTEX_NOT_HELD(x)	(!mutex_owned(x) || panicstr)
81 
82 /*
83  * We're simulating the kernel mutex API here, and the
84  * user-level has a different signature, so rename.
85  */
86 #define	mutex_init	kmutex_init
87 #define	mutex_destroy	kmutex_destroy
88 
89 /*
90  * We want to avoid binding against the versions of these
91  * functions in libc which causes bad things to happen.
92  */
93 #define	mutex_enter	kmutex_enter
94 #define	mutex_exit	kmutex_exit
95 
96 extern	void	kmutex_init(kmutex_t *, char *, kmutex_type_t, void *);
97 extern	void	kmutex_destroy(kmutex_t *);
98 
99 extern	void	kmutex_enter(kmutex_t *);
100 extern	void	kmutex_exit(kmutex_t *);
101 
102 extern	int	mutex_tryenter(kmutex_t *);
103 extern	int	mutex_owned(const kmutex_t *);
104 
105 extern	void *mutex_owner(const kmutex_t *);
106 
107 #ifdef	__cplusplus
108 }
109 #endif
110 
111 #endif	/* _SYS_MUTEX_H */
112