diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-alpha/semaphore.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-alpha/semaphore.h')
-rw-r--r-- | include/asm-alpha/semaphore.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/include/asm-alpha/semaphore.h b/include/asm-alpha/semaphore.h new file mode 100644 index 000000000000..eb2cbd97d404 --- /dev/null +++ b/include/asm-alpha/semaphore.h | |||
@@ -0,0 +1,153 @@ | |||
1 | #ifndef _ALPHA_SEMAPHORE_H | ||
2 | #define _ALPHA_SEMAPHORE_H | ||
3 | |||
4 | /* | ||
5 | * SMP- and interrupt-safe semaphores.. | ||
6 | * | ||
7 | * (C) Copyright 1996 Linus Torvalds | ||
8 | * (C) Copyright 1996, 2000 Richard Henderson | ||
9 | */ | ||
10 | |||
11 | #include <asm/current.h> | ||
12 | #include <asm/system.h> | ||
13 | #include <asm/atomic.h> | ||
14 | #include <linux/compiler.h> | ||
15 | #include <linux/wait.h> | ||
16 | #include <linux/rwsem.h> | ||
17 | |||
18 | struct semaphore { | ||
19 | atomic_t count; | ||
20 | wait_queue_head_t wait; | ||
21 | }; | ||
22 | |||
23 | #define __SEMAPHORE_INITIALIZER(name, n) \ | ||
24 | { \ | ||
25 | .count = ATOMIC_INIT(n), \ | ||
26 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ | ||
27 | } | ||
28 | |||
29 | #define __MUTEX_INITIALIZER(name) \ | ||
30 | __SEMAPHORE_INITIALIZER(name,1) | ||
31 | |||
32 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ | ||
33 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) | ||
34 | |||
35 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | ||
36 | #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) | ||
37 | |||
38 | static inline void sema_init(struct semaphore *sem, int val) | ||
39 | { | ||
40 | /* | ||
41 | * Logically, | ||
42 | * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); | ||
43 | * except that gcc produces better initializing by parts yet. | ||
44 | */ | ||
45 | |||
46 | atomic_set(&sem->count, val); | ||
47 | init_waitqueue_head(&sem->wait); | ||
48 | } | ||
49 | |||
50 | static inline void init_MUTEX (struct semaphore *sem) | ||
51 | { | ||
52 | sema_init(sem, 1); | ||
53 | } | ||
54 | |||
55 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | ||
56 | { | ||
57 | sema_init(sem, 0); | ||
58 | } | ||
59 | |||
60 | extern void down(struct semaphore *); | ||
61 | extern void __down_failed(struct semaphore *); | ||
62 | extern int down_interruptible(struct semaphore *); | ||
63 | extern int __down_failed_interruptible(struct semaphore *); | ||
64 | extern int down_trylock(struct semaphore *); | ||
65 | extern void up(struct semaphore *); | ||
66 | extern void __up_wakeup(struct semaphore *); | ||
67 | |||
68 | /* | ||
69 | * Hidden out of line code is fun, but extremely messy. Rely on newer | ||
70 | * compilers to do a respectable job with this. The contention cases | ||
71 | * are handled out of line in arch/alpha/kernel/semaphore.c. | ||
72 | */ | ||
73 | |||
74 | static inline void __down(struct semaphore *sem) | ||
75 | { | ||
76 | long count; | ||
77 | might_sleep(); | ||
78 | count = atomic_dec_return(&sem->count); | ||
79 | if (unlikely(count < 0)) | ||
80 | __down_failed(sem); | ||
81 | } | ||
82 | |||
83 | static inline int __down_interruptible(struct semaphore *sem) | ||
84 | { | ||
85 | long count; | ||
86 | might_sleep(); | ||
87 | count = atomic_dec_return(&sem->count); | ||
88 | if (unlikely(count < 0)) | ||
89 | return __down_failed_interruptible(sem); | ||
90 | return 0; | ||
91 | } | ||
92 | |||
93 | /* | ||
94 | * down_trylock returns 0 on success, 1 if we failed to get the lock. | ||
95 | */ | ||
96 | |||
97 | static inline int __down_trylock(struct semaphore *sem) | ||
98 | { | ||
99 | long ret; | ||
100 | |||
101 | /* "Equivalent" C: | ||
102 | |||
103 | do { | ||
104 | ret = ldl_l; | ||
105 | --ret; | ||
106 | if (ret < 0) | ||
107 | break; | ||
108 | ret = stl_c = ret; | ||
109 | } while (ret == 0); | ||
110 | */ | ||
111 | __asm__ __volatile__( | ||
112 | "1: ldl_l %0,%1\n" | ||
113 | " subl %0,1,%0\n" | ||
114 | " blt %0,2f\n" | ||
115 | " stl_c %0,%1\n" | ||
116 | " beq %0,3f\n" | ||
117 | " mb\n" | ||
118 | "2:\n" | ||
119 | ".subsection 2\n" | ||
120 | "3: br 1b\n" | ||
121 | ".previous" | ||
122 | : "=&r" (ret), "=m" (sem->count) | ||
123 | : "m" (sem->count)); | ||
124 | |||
125 | return ret < 0; | ||
126 | } | ||
127 | |||
128 | static inline void __up(struct semaphore *sem) | ||
129 | { | ||
130 | if (unlikely(atomic_inc_return(&sem->count) <= 0)) | ||
131 | __up_wakeup(sem); | ||
132 | } | ||
133 | |||
134 | #if !defined(CONFIG_DEBUG_SEMAPHORE) | ||
135 | extern inline void down(struct semaphore *sem) | ||
136 | { | ||
137 | __down(sem); | ||
138 | } | ||
139 | extern inline int down_interruptible(struct semaphore *sem) | ||
140 | { | ||
141 | return __down_interruptible(sem); | ||
142 | } | ||
143 | extern inline int down_trylock(struct semaphore *sem) | ||
144 | { | ||
145 | return __down_trylock(sem); | ||
146 | } | ||
147 | extern inline void up(struct semaphore *sem) | ||
148 | { | ||
149 | __up(sem); | ||
150 | } | ||
151 | #endif | ||
152 | |||
153 | #endif | ||