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authorMatthew Wilcox <matthew@wil.cx>2008-03-07 21:55:58 -0500
committerMatthew Wilcox <willy@linux.intel.com>2008-04-17 10:42:34 -0400
commit64ac24e738823161693bf791f87adc802cf529ff (patch)
tree19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-sparc
parente48b3deee475134585eed03e7afebe4bf9e0dba9 (diff)
Generic semaphore implementation
Semaphores are no longer performance-critical, so a generic C implementation is better for maintainability, debuggability and extensibility. Thanks to Peter Zijlstra for fixing the lockdep warning. Thanks to Harvey Harrison for pointing out that the unlikely() was unnecessary. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Acked-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-sparc')
-rw-r--r--include/asm-sparc/semaphore.h193
1 files changed, 1 insertions, 192 deletions
diff --git a/include/asm-sparc/semaphore.h b/include/asm-sparc/semaphore.h
index 8018f9f4d497..d9b2034ed1d2 100644
--- a/include/asm-sparc/semaphore.h
+++ b/include/asm-sparc/semaphore.h
@@ -1,192 +1 @@
1#ifndef _SPARC_SEMAPHORE_H #include <linux/semaphore.h>
2#define _SPARC_SEMAPHORE_H
3
4/* Dinky, good for nothing, just barely irq safe, Sparc semaphores. */
5
6#ifdef __KERNEL__
7
8#include <asm/atomic.h>
9#include <linux/wait.h>
10#include <linux/rwsem.h>
11
12struct semaphore {
13 atomic24_t count;
14 int sleepers;
15 wait_queue_head_t wait;
16};
17
18#define __SEMAPHORE_INITIALIZER(name, n) \
19{ \
20 .count = ATOMIC24_INIT(n), \
21 .sleepers = 0, \
22 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
23}
24
25#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
26 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
27
28#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
29
30static inline void sema_init (struct semaphore *sem, int val)
31{
32 atomic24_set(&sem->count, val);
33 sem->sleepers = 0;
34 init_waitqueue_head(&sem->wait);
35}
36
37static inline void init_MUTEX (struct semaphore *sem)
38{
39 sema_init(sem, 1);
40}
41
42static inline void init_MUTEX_LOCKED (struct semaphore *sem)
43{
44 sema_init(sem, 0);
45}
46
47extern void __down(struct semaphore * sem);
48extern int __down_interruptible(struct semaphore * sem);
49extern int __down_trylock(struct semaphore * sem);
50extern void __up(struct semaphore * sem);
51
52static inline void down(struct semaphore * sem)
53{
54 register volatile int *ptr asm("g1");
55 register int increment asm("g2");
56
57 might_sleep();
58
59 ptr = &(sem->count.counter);
60 increment = 1;
61
62 __asm__ __volatile__(
63 "mov %%o7, %%g4\n\t"
64 "call ___atomic24_sub\n\t"
65 " add %%o7, 8, %%o7\n\t"
66 "tst %%g2\n\t"
67 "bl 2f\n\t"
68 " nop\n"
69 "1:\n\t"
70 ".subsection 2\n"
71 "2:\n\t"
72 "save %%sp, -64, %%sp\n\t"
73 "mov %%g1, %%l1\n\t"
74 "mov %%g5, %%l5\n\t"
75 "call %3\n\t"
76 " mov %%g1, %%o0\n\t"
77 "mov %%l1, %%g1\n\t"
78 "ba 1b\n\t"
79 " restore %%l5, %%g0, %%g5\n\t"
80 ".previous\n"
81 : "=&r" (increment)
82 : "0" (increment), "r" (ptr), "i" (__down)
83 : "g3", "g4", "g7", "memory", "cc");
84}
85
86static inline int down_interruptible(struct semaphore * sem)
87{
88 register volatile int *ptr asm("g1");
89 register int increment asm("g2");
90
91 might_sleep();
92
93 ptr = &(sem->count.counter);
94 increment = 1;
95
96 __asm__ __volatile__(
97 "mov %%o7, %%g4\n\t"
98 "call ___atomic24_sub\n\t"
99 " add %%o7, 8, %%o7\n\t"
100 "tst %%g2\n\t"
101 "bl 2f\n\t"
102 " clr %%g2\n"
103 "1:\n\t"
104 ".subsection 2\n"
105 "2:\n\t"
106 "save %%sp, -64, %%sp\n\t"
107 "mov %%g1, %%l1\n\t"
108 "mov %%g5, %%l5\n\t"
109 "call %3\n\t"
110 " mov %%g1, %%o0\n\t"
111 "mov %%l1, %%g1\n\t"
112 "mov %%l5, %%g5\n\t"
113 "ba 1b\n\t"
114 " restore %%o0, %%g0, %%g2\n\t"
115 ".previous\n"
116 : "=&r" (increment)
117 : "0" (increment), "r" (ptr), "i" (__down_interruptible)
118 : "g3", "g4", "g7", "memory", "cc");
119
120 return increment;
121}
122
123static inline int down_trylock(struct semaphore * sem)
124{
125 register volatile int *ptr asm("g1");
126 register int increment asm("g2");
127
128 ptr = &(sem->count.counter);
129 increment = 1;
130
131 __asm__ __volatile__(
132 "mov %%o7, %%g4\n\t"
133 "call ___atomic24_sub\n\t"
134 " add %%o7, 8, %%o7\n\t"
135 "tst %%g2\n\t"
136 "bl 2f\n\t"
137 " clr %%g2\n"
138 "1:\n\t"
139 ".subsection 2\n"
140 "2:\n\t"
141 "save %%sp, -64, %%sp\n\t"
142 "mov %%g1, %%l1\n\t"
143 "mov %%g5, %%l5\n\t"
144 "call %3\n\t"
145 " mov %%g1, %%o0\n\t"
146 "mov %%l1, %%g1\n\t"
147 "mov %%l5, %%g5\n\t"
148 "ba 1b\n\t"
149 " restore %%o0, %%g0, %%g2\n\t"
150 ".previous\n"
151 : "=&r" (increment)
152 : "0" (increment), "r" (ptr), "i" (__down_trylock)
153 : "g3", "g4", "g7", "memory", "cc");
154
155 return increment;
156}
157
158static inline void up(struct semaphore * sem)
159{
160 register volatile int *ptr asm("g1");
161 register int increment asm("g2");
162
163 ptr = &(sem->count.counter);
164 increment = 1;
165
166 __asm__ __volatile__(
167 "mov %%o7, %%g4\n\t"
168 "call ___atomic24_add\n\t"
169 " add %%o7, 8, %%o7\n\t"
170 "tst %%g2\n\t"
171 "ble 2f\n\t"
172 " nop\n"
173 "1:\n\t"
174 ".subsection 2\n"
175 "2:\n\t"
176 "save %%sp, -64, %%sp\n\t"
177 "mov %%g1, %%l1\n\t"
178 "mov %%g5, %%l5\n\t"
179 "call %3\n\t"
180 " mov %%g1, %%o0\n\t"
181 "mov %%l1, %%g1\n\t"
182 "ba 1b\n\t"
183 " restore %%l5, %%g0, %%g5\n\t"
184 ".previous\n"
185 : "=&r" (increment)
186 : "0" (increment), "r" (ptr), "i" (__up)
187 : "g3", "g4", "g7", "memory", "cc");
188}
189
190#endif /* __KERNEL__ */
191
192#endif /* !(_SPARC_SEMAPHORE_H) */
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