diff options
Diffstat (limited to 'include/asm-s390/semaphore.h')
-rw-r--r-- | include/asm-s390/semaphore.h | 108 |
1 files changed, 1 insertions, 107 deletions
diff --git a/include/asm-s390/semaphore.h b/include/asm-s390/semaphore.h index 0e7001ad8392..d9b2034ed1d2 100644 --- a/include/asm-s390/semaphore.h +++ b/include/asm-s390/semaphore.h | |||
@@ -1,107 +1 @@ | |||
1 | /* | #include <linux/semaphore.h> | |
2 | * include/asm-s390/semaphore.h | ||
3 | * | ||
4 | * S390 version | ||
5 | * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation | ||
6 | * | ||
7 | * Derived from "include/asm-i386/semaphore.h" | ||
8 | * (C) Copyright 1996 Linus Torvalds | ||
9 | */ | ||
10 | |||
11 | #ifndef _S390_SEMAPHORE_H | ||
12 | #define _S390_SEMAPHORE_H | ||
13 | |||
14 | #include <asm/system.h> | ||
15 | #include <asm/atomic.h> | ||
16 | #include <linux/wait.h> | ||
17 | #include <linux/rwsem.h> | ||
18 | |||
19 | struct semaphore { | ||
20 | /* | ||
21 | * Note that any negative value of count is equivalent to 0, | ||
22 | * but additionally indicates that some process(es) might be | ||
23 | * sleeping on `wait'. | ||
24 | */ | ||
25 | atomic_t count; | ||
26 | wait_queue_head_t wait; | ||
27 | }; | ||
28 | |||
29 | #define __SEMAPHORE_INITIALIZER(name,count) \ | ||
30 | { ATOMIC_INIT(count), __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) } | ||
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 | |||
37 | static inline void sema_init (struct semaphore *sem, int val) | ||
38 | { | ||
39 | atomic_set(&sem->count, val); | ||
40 | init_waitqueue_head(&sem->wait); | ||
41 | } | ||
42 | |||
43 | static inline void init_MUTEX (struct semaphore *sem) | ||
44 | { | ||
45 | sema_init(sem, 1); | ||
46 | } | ||
47 | |||
48 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | ||
49 | { | ||
50 | sema_init(sem, 0); | ||
51 | } | ||
52 | |||
53 | asmlinkage void __down(struct semaphore * sem); | ||
54 | asmlinkage int __down_interruptible(struct semaphore * sem); | ||
55 | asmlinkage int __down_trylock(struct semaphore * sem); | ||
56 | asmlinkage void __up(struct semaphore * sem); | ||
57 | |||
58 | static inline void down(struct semaphore * sem) | ||
59 | { | ||
60 | might_sleep(); | ||
61 | if (atomic_dec_return(&sem->count) < 0) | ||
62 | __down(sem); | ||
63 | } | ||
64 | |||
65 | static inline int down_interruptible(struct semaphore * sem) | ||
66 | { | ||
67 | int ret = 0; | ||
68 | |||
69 | might_sleep(); | ||
70 | if (atomic_dec_return(&sem->count) < 0) | ||
71 | ret = __down_interruptible(sem); | ||
72 | return ret; | ||
73 | } | ||
74 | |||
75 | static inline int down_trylock(struct semaphore * sem) | ||
76 | { | ||
77 | int old_val, new_val; | ||
78 | |||
79 | /* | ||
80 | * This inline assembly atomically implements the equivalent | ||
81 | * to the following C code: | ||
82 | * old_val = sem->count.counter; | ||
83 | * if ((new_val = old_val) > 0) | ||
84 | * sem->count.counter = --new_val; | ||
85 | * In the ppc code this is called atomic_dec_if_positive. | ||
86 | */ | ||
87 | asm volatile( | ||
88 | " l %0,0(%3)\n" | ||
89 | "0: ltr %1,%0\n" | ||
90 | " jle 1f\n" | ||
91 | " ahi %1,-1\n" | ||
92 | " cs %0,%1,0(%3)\n" | ||
93 | " jl 0b\n" | ||
94 | "1:" | ||
95 | : "=&d" (old_val), "=&d" (new_val), "=m" (sem->count.counter) | ||
96 | : "a" (&sem->count.counter), "m" (sem->count.counter) | ||
97 | : "cc", "memory"); | ||
98 | return old_val <= 0; | ||
99 | } | ||
100 | |||
101 | static inline void up(struct semaphore * sem) | ||
102 | { | ||
103 | if (atomic_inc_return(&sem->count) <= 0) | ||
104 | __up(sem); | ||
105 | } | ||
106 | |||
107 | #endif | ||