![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to lock.h CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Apple Darwin 0.x] / kernel / kern|
Return to lock.h CVS log | Up to [Apple Darwin 0.x] / kernel / kern |
1.1 root 1: /*
2: * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
7: * Reserved. This file contains Original Code and/or Modifications of
8: * Original Code as defined in and that are subject to the Apple Public
9: * Source License Version 1.1 (the "License"). You may not use this file
10: * except in compliance with the License. Please obtain a copy of the
11: * License at http://www.apple.com/publicsource and read it before using
12: * this file.
13: *
14: * The Original Code and all software distributed under the License are
15: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
19: * License for the specific language governing rights and limitations
20: * under the License.
21: *
22: * @APPLE_LICENSE_HEADER_END@
23: */
24:
25: /*
26: * Mach Operating System
27: * Copyright (c) 1993-1987 Carnegie Mellon University
28: * All Rights Reserved.
29: *
30: * Permission to use, copy, modify and distribute this software and its
31: * documentation is hereby granted, provided that both the copyright
32: * notice and this permission notice appear in all copies of the
33: * software, derivative works or modified versions, and any portions
34: * thereof, and that both notices appear in supporting documentation.
35: *
36: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
37: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
38: * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
39: *
40: * Carnegie Mellon requests users of this software to return to
41: *
42: * Software Distribution Coordinator or [email protected]
43: * School of Computer Science
44: * Carnegie Mellon University
45: * Pittsburgh PA 15213-3890
46: *
47: * any improvements or extensions that they make and grant Carnegie Mellon
48: * the rights to redistribute these changes.
49: */
50: /*
51: * File: kern/lock.h
52: * Author: Avadis Tevanian, Jr., Michael Wayne Young
53: * Date: 1985
54: *
55: * Locking primitives definitions
56: */
57:
58: #ifndef _KERN_LOCK_H_
59: #define _KERN_LOCK_H_
60:
61: #import <mach/features.h>
62:
63: #include <mach/boolean.h>
64: #include <mach/machine/vm_types.h>
65:
66: #define MACH_SLOCKS ((NCPUS > 1) || MACH_LDEBUG || DRIVERKIT)
67:
68: #ifndef _MACHINE_SIMPLE_LOCK_DATA_
69: /*
70: * A simple spin lock.
71: */
72:
73: struct slock {
74: volatile natural_t lock_data; /* in general 1 bit is sufficient */
75: };
76:
77: typedef struct slock simple_lock_data_t;
78: typedef struct slock *simple_lock_t;
79: #endif /* _MACHINE_SIMPLE_LOCK_DATA_ */
80:
81: #if MACH_SLOCKS
82: /*
83: * Use the locks.
84: */
85:
86: #define decl_simple_lock_data(class,name) \
87: class simple_lock_data_t name;
88:
89: #define simple_lock_addr(lock) (&(lock))
90:
91: #else /* MACH_SLOCKS */
92: /*
93: * Do not allocate storage for locks if not needed.
94: */
95: #define decl_simple_lock_data(class,name)
96: #define simple_lock_addr(lock) ((simple_lock_t)0)
97:
98: /*
99: * No multiprocessor locking is necessary.
100: */
101: #define simple_lock_init(l)
102: #define simple_lock(l)
103: #define simple_unlock(l)
104: #define simple_lock_try(l) (TRUE) /* always succeeds */
105: #define simple_lock_taken(l) (1) /* always succeeds */
106: #define check_simple_locks()
107: #define simple_lock_pause()
108:
109: #endif /* MACH_SLOCKS */
110:
111: extern simple_lock_t simple_lock_alloc(void);
112: extern void simple_lock_free(simple_lock_t);
113:
114: /*
115: * The general lock structure. Provides for multiple readers,
116: * upgrading from read to write, and sleeping until the lock
117: * can be gained.
118: *
119: * On some architectures, assembly language code in the 'inline'
120: * program fiddles the lock structures. It must be changed in
121: * concert with the structure layout.
122: *
123: * Only the "interlock" field is used for hardware exclusion;
124: * other fields are modified with normal instructions after
125: * acquiring the interlock bit.
126: */
127: struct lock {
128: struct thread *thread; /* Thread that has lock, if
129: recursive locking allowed */
130: unsigned int read_count:16, /* Number of accepted readers */
131: /* boolean_t */ want_upgrade:1, /* Read-to-write upgrade waiting */
132: /* boolean_t */ want_write:1, /* Writer is waiting, or
133: locked for write */
134: /* boolean_t */ waiting:1, /* Someone is sleeping on lock */
135: /* boolean_t */ can_sleep:1, /* Can attempts to lock go to sleep? */
136: recursion_depth:12, /* Depth of recursion */
137: :0;
138: decl_simple_lock_data(,interlock)
139: /* Hardware interlock field.
140: Last in the structure so that
141: field offsets are the same whether
142: or not it is present. */
143: };
144:
145: typedef struct lock lock_data_t;
146: typedef struct lock *lock_t;
147:
148: /* Sleep locks must work even if no multiprocessing */
149:
150: extern void lock_init(lock_t, boolean_t);
151: extern void lock_sleepable(lock_t, boolean_t);
152: extern void lock_write(lock_t);
153: extern void lock_read(lock_t);
154: extern void lock_done(lock_t);
155: extern boolean_t lock_read_to_write(lock_t);
156: extern void lock_write_to_read(lock_t);
157: extern boolean_t lock_try_write(lock_t);
158: extern boolean_t lock_try_read(lock_t);
159: extern boolean_t lock_try_read_to_write(lock_t);
160:
161: #define lock_read_done(l) lock_done(l)
162: #define lock_write_done(l) lock_done(l)
163:
164: extern void lock_set_recursive(lock_t);
165: extern void lock_clear_recursive(lock_t);
166:
167: extern lock_t lock_alloc(void);
168: extern void lock_free(lock_t);
169:
170: #endif /* _KERN_LOCK_H_ */
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.