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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-h8300
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-h8300')
-rw-r--r--include/asm-h8300/semaphore-helper.h85
-rw-r--r--include/asm-h8300/semaphore.h191
2 files changed, 1 insertions, 275 deletions
diff --git a/include/asm-h8300/semaphore-helper.h b/include/asm-h8300/semaphore-helper.h
deleted file mode 100644
index 4fea36be5fd8..000000000000
--- a/include/asm-h8300/semaphore-helper.h
+++ /dev/null
@@ -1,85 +0,0 @@
1#ifndef _H8300_SEMAPHORE_HELPER_H
2#define _H8300_SEMAPHORE_HELPER_H
3
4/*
5 * SMP- and interrupt-safe semaphores helper functions.
6 *
7 * (C) Copyright 1996 Linus Torvalds
8 *
9 * based on
10 * m68k version by Andreas Schwab
11 */
12
13#include <linux/errno.h>
14
15/*
16 * These two _must_ execute atomically wrt each other.
17 */
18static inline void wake_one_more(struct semaphore * sem)
19{
20 atomic_inc((atomic_t *)&sem->sleepers);
21}
22
23static inline int waking_non_zero(struct semaphore *sem)
24{
25 int ret;
26 unsigned long flags;
27
28 spin_lock_irqsave(&semaphore_wake_lock, flags);
29 ret = 0;
30 if (sem->sleepers > 0) {
31 sem->sleepers--;
32 ret = 1;
33 }
34 spin_unlock_irqrestore(&semaphore_wake_lock, flags);
35 return ret;
36}
37
38/*
39 * waking_non_zero_interruptible:
40 * 1 got the lock
41 * 0 go to sleep
42 * -EINTR interrupted
43 */
44static inline int waking_non_zero_interruptible(struct semaphore *sem,
45 struct task_struct *tsk)
46{
47 int ret;
48 unsigned long flags;
49
50 spin_lock_irqsave(&semaphore_wake_lock, flags);
51 ret = 0;
52 if (sem->sleepers > 0) {
53 sem->sleepers--;
54 ret = 1;
55 } else if (signal_pending(tsk)) {
56 atomic_inc(&sem->count);
57 ret = -EINTR;
58 }
59 spin_unlock_irqrestore(&semaphore_wake_lock, flags);
60 return ret;
61}
62
63/*
64 * waking_non_zero_trylock:
65 * 1 failed to lock
66 * 0 got the lock
67 */
68static inline int waking_non_zero_trylock(struct semaphore *sem)
69{
70 int ret;
71 unsigned long flags;
72
73 spin_lock_irqsave(&semaphore_wake_lock, flags);
74 ret = 1;
75 if (sem->sleepers <= 0)
76 atomic_inc(&sem->count);
77 else {
78 sem->sleepers--;
79 ret = 0;
80 }
81 spin_unlock_irqrestore(&semaphore_wake_lock, flags);
82 return ret;
83}
84
85#endif
diff --git a/include/asm-h8300/semaphore.h b/include/asm-h8300/semaphore.h
index f3ffff83ff09..d9b2034ed1d2 100644
--- a/include/asm-h8300/semaphore.h
+++ b/include/asm-h8300/semaphore.h
@@ -1,190 +1 @@
1#ifndef _H8300_SEMAPHORE_H #include <linux/semaphore.h>
2#define _H8300_SEMAPHORE_H
3
4#define RW_LOCK_BIAS 0x01000000
5
6#ifndef __ASSEMBLY__
7
8#include <linux/linkage.h>
9#include <linux/wait.h>
10#include <linux/spinlock.h>
11#include <linux/rwsem.h>
12
13#include <asm/system.h>
14#include <asm/atomic.h>
15
16/*
17 * Interrupt-safe semaphores..
18 *
19 * (C) Copyright 1996 Linus Torvalds
20 *
21 * H8/300 version by Yoshinori Sato
22 */
23
24
25struct semaphore {
26 atomic_t count;
27 int sleepers;
28 wait_queue_head_t wait;
29};
30
31#define __SEMAPHORE_INITIALIZER(name, n) \
32{ \
33 .count = ATOMIC_INIT(n), \
34 .sleepers = 0, \
35 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
36}
37
38#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
39 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
40
41#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
42
43static inline void sema_init (struct semaphore *sem, int val)
44{
45 *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
46}
47
48static inline void init_MUTEX (struct semaphore *sem)
49{
50 sema_init(sem, 1);
51}
52
53static inline void init_MUTEX_LOCKED (struct semaphore *sem)
54{
55 sema_init(sem, 0);
56}
57
58asmlinkage void __down_failed(void /* special register calling convention */);
59asmlinkage int __down_failed_interruptible(void /* params in registers */);
60asmlinkage int __down_failed_trylock(void /* params in registers */);
61asmlinkage void __up_wakeup(void /* special register calling convention */);
62
63asmlinkage void __down(struct semaphore * sem);
64asmlinkage int __down_interruptible(struct semaphore * sem);
65asmlinkage int __down_trylock(struct semaphore * sem);
66asmlinkage void __up(struct semaphore * sem);
67
68extern spinlock_t semaphore_wake_lock;
69
70/*
71 * This is ugly, but we want the default case to fall through.
72 * "down_failed" is a special asm handler that calls the C
73 * routine that actually waits. See arch/m68k/lib/semaphore.S
74 */
75static inline void down(struct semaphore * sem)
76{
77 register atomic_t *count asm("er0");
78
79 might_sleep();
80
81 count = &(sem->count);
82 __asm__ __volatile__(
83 "stc ccr,r3l\n\t"
84 "orc #0x80,ccr\n\t"
85 "mov.l %2, er1\n\t"
86 "dec.l #1,er1\n\t"
87 "mov.l er1,%0\n\t"
88 "bpl 1f\n\t"
89 "ldc r3l,ccr\n\t"
90 "mov.l %1,er0\n\t"
91 "jsr @___down\n\t"
92 "bra 2f\n"
93 "1:\n\t"
94 "ldc r3l,ccr\n"
95 "2:"
96 : "=m"(*count)
97 : "g"(sem),"m"(*count)
98 : "cc", "er1", "er2", "er3");
99}
100
101static inline int down_interruptible(struct semaphore * sem)
102{
103 register atomic_t *count asm("er0");
104
105 might_sleep();
106
107 count = &(sem->count);
108 __asm__ __volatile__(
109 "stc ccr,r1l\n\t"
110 "orc #0x80,ccr\n\t"
111 "mov.l %3, er2\n\t"
112 "dec.l #1,er2\n\t"
113 "mov.l er2,%1\n\t"
114 "bpl 1f\n\t"
115 "ldc r1l,ccr\n\t"
116 "mov.l %2,er0\n\t"
117 "jsr @___down_interruptible\n\t"
118 "bra 2f\n"
119 "1:\n\t"
120 "ldc r1l,ccr\n\t"
121 "sub.l %0,%0\n\t"
122 "2:\n\t"
123 : "=r" (count),"=m" (*count)
124 : "g"(sem),"m"(*count)
125 : "cc", "er1", "er2", "er3");
126 return (int)count;
127}
128
129static inline int down_trylock(struct semaphore * sem)
130{
131 register atomic_t *count asm("er0");
132
133 count = &(sem->count);
134 __asm__ __volatile__(
135 "stc ccr,r3l\n\t"
136 "orc #0x80,ccr\n\t"
137 "mov.l %3,er2\n\t"
138 "dec.l #1,er2\n\t"
139 "mov.l er2,%0\n\t"
140 "bpl 1f\n\t"
141 "ldc r3l,ccr\n\t"
142 "jmp @3f\n\t"
143 LOCK_SECTION_START(".align 2\n\t")
144 "3:\n\t"
145 "mov.l %2,er0\n\t"
146 "jsr @___down_trylock\n\t"
147 "jmp @2f\n\t"
148 LOCK_SECTION_END
149 "1:\n\t"
150 "ldc r3l,ccr\n\t"
151 "sub.l %1,%1\n"
152 "2:"
153 : "=m" (*count),"=r"(count)
154 : "g"(sem),"m"(*count)
155 : "cc", "er1","er2", "er3");
156 return (int)count;
157}
158
159/*
160 * Note! This is subtle. We jump to wake people up only if
161 * the semaphore was negative (== somebody was waiting on it).
162 * The default case (no contention) will result in NO
163 * jumps for both down() and up().
164 */
165static inline void up(struct semaphore * sem)
166{
167 register atomic_t *count asm("er0");
168
169 count = &(sem->count);
170 __asm__ __volatile__(
171 "stc ccr,r3l\n\t"
172 "orc #0x80,ccr\n\t"
173 "mov.l %2,er1\n\t"
174 "inc.l #1,er1\n\t"
175 "mov.l er1,%0\n\t"
176 "ldc r3l,ccr\n\t"
177 "sub.l er2,er2\n\t"
178 "cmp.l er2,er1\n\t"
179 "bgt 1f\n\t"
180 "mov.l %1,er0\n\t"
181 "jsr @___up\n"
182 "1:"
183 : "=m"(*count)
184 : "g"(sem),"m"(*count)
185 : "cc", "er1", "er2", "er3");
186}
187
188#endif /* __ASSEMBLY__ */
189
190#endif
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