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1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /*
23: * @OSF_COPYRIGHT@
24: *
25: */
26: /*
27: * HISTORY
28: *
29: * Revision 1.1.1.1 1998/09/22 21:05:30 wsanchez
30: * Import of Mac OS X kernel (~semeria)
31: *
32: * Revision 1.1.1.1 1998/03/07 02:25:45 wsanchez
33: * Import of OSF Mach kernel (~mburg)
34: *
35: * Revision 1.1.4.1 1995/06/13 18:20:29 sjs
36: * Merged from flipc_shared.
37: * [95/06/07 sjs]
38: *
39: * Revision 1.1.2.3 1995/03/09 19:42:30 rwd
40: * Move yield function out of macro and prototype.
41: * [1995/03/09 19:36:25 rwd]
42: *
43: * Revision 1.1.2.2 1995/02/21 17:23:11 randys
44: * Re-indented code to four space indentation
45: * [1995/02/21 16:25:39 randys]
46: *
47: * Revision 1.1.2.1 1994/12/20 19:02:06 randys
48: * Moved definition of flipc_simple_lock to flipc_cb.h
49: * [1994/12/20 17:34:44 randys]
50: *
51: * Separated the lock macros out into machine dependent and independent files;
52: * this is the machine independent file.
53: * [1994/12/20 16:43:38 randys]
54: *
55: * $EndLog$
56: */
57:
58: /*
59: * mach/flipc_locks.h
60: *
61: * The machine independent part of the flipc_simple_locks definitions.
62: * Most of the locks definitions is in flipc_dep.h, but what isn't
63: * dependent on the platform being used is here.
64: */
65:
66: /*
67: * Note that the locks defined in this file and in flipc_dep.h are only
68: * for use by user level code. The reason why this file is visible to
69: * the kernel is that the kernel section of flipc needs to initialize
70: * these locks.
71: */
72:
73: #ifndef _MACH_FLIPC_LOCKS_H_
74: #define _MACH_FLIPC_LOCKS_H_
75:
76: /* Get the simple lock type. */
77: #include <mach/flipc_cb.h>
78:
79: /*
80: * Lock function prototypes. This needs to be before any lock definitions
81: * that happen to be macros.
82: */
83:
84: /* Initializes lock. Always a macro (so that kernel code can use it without
85: library assistance). */
86: void flipc_simple_lock_init(flipc_simple_lock *lock);
87:
88: /* Returns 1 if lock gained, 0 otherwise. */
89: int flipc_simple_lock_try(flipc_simple_lock *lock);
90:
91: /* Returns 1 if lock is locked, 0 otherwise. */
92: int flipc_simple_lock_locked(flipc_simple_lock *lock);
93:
94: /* Releases the lock. */
95: void flipc_simple_lock_release(flipc_simple_lock *lock);
96:
97: /* Take the lock. */
98: void flipc_simple_lock_acquire(flipc_simple_lock *lock);
99:
100: /* Take two locks. Does not hold one while spinning on the
101: other. */
102: void flipc_simple_lock_acquire_2(flipc_simple_lock *lock1,
103: flipc_simple_lock *lock2);
104:
105: /* Get the machine dependent stuff. The things that need to be
106: * defined in a machine dependent fashion are:
107: *
108: * flipc_simple_lock_init (must be a macro)
109: * flipc_simple_lock_try
110: * flipc_simple_lock_locked
111: * flipc_simple_lock_release
112: *
113: * These last three don't necessarily have to be macros, but if they
114: * aren't definitions must be included in the machine dependent
115: * part of the user level library code.
116: */
117: #include <mach/machine/flipc_dep.h>
118:
119: /*
120: * Set at flipc initialization time to thread_yield argument to
121: * FLIPC_domain_init
122: */
123:
124: extern void (*flipc_simple_lock_yield_fn)(void);
125:
126: /*
127: * Machine independent definitions; defined in terms of above routines.
128: */
129:
130: /* Take the lock. Assumes an external define saying how long to
131: spin, and an external function to call when we've spun too long. */
132: #define flipc_simple_lock_acquire(lock) \
133: do { \
134: int __spin_count = 0; \
135: \
136: while (flipc_simple_lock_locked(lock) \
137: || !flipc_simple_lock_try(lock)) \
138: if (++__spin_count > LOCK_SPIN_LIMIT) { \
139: (*flipc_simple_lock_yield_fn)(); \
140: __spin_count = 0; \
141: } \
142: } while (0)
143:
144: /* Take two locks. Hold neither while spinning on the other. */
145: #define flipc_simple_lock_acquire_2(lock1, lock2) \
146: do { \
147: int __spin_count = 0; \
148: \
149: while (1) { \
150: while (flipc_simple_lock_locked(lock1) \
151: || !flipc_simple_lock_try(lock1)) \
152: if (++__spin_count > LOCK_SPIN_LIMIT) { \
153: (*flipc_simple_lock_yield_fn)(); \
154: __spin_count = 0; \
155: } \
156: \
157: if (flipc_simple_lock_try(lock2)) \
158: break; \
159: flipc_simple_lock_release(lock1); \
160: \
161: while (flipc_simple_lock_locked(lock2) \
162: || !flipc_simple_lock_try(lock2)) \
163: if (++__spin_count > LOCK_SPIN_LIMIT) { \
164: (*flipc_simple_lock_yield_fn)(); \
165: __spin_count = 0; \
166: } \
167: \
168: if (flipc_simple_lock_try(lock1)) \
169: break; \
170: flipc_simple_lock_release(lock2); \
171: } \
172: } while (0)
173:
174: #endif /* _MACH_FLIPC_LOCKS_H_ */
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