1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
/*
* linux/include/asm-arm/semaphore.h
*/
#ifndef __ASM_ARM_SEMAPHORE_H
#define __ASM_ARM_SEMAPHORE_H
#include <linux/linkage.h>
#include <asm/system.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int waking;
struct wait_queue * wait;
};
#define MUTEX ((struct semaphore) { ATOMIC_INIT(1), 0, NULL })
#define MUTEX_LOCKED ((struct semaphore) { ATOMIC_INIT(0), 0, NULL })
asmlinkage void __down_failed (void /* special register calling convention */);
asmlinkage int __down_interruptible_failed (void /* special register calling convention */);
asmlinkage void __up_wakeup (void /* special register calling convention */);
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
#define sema_init(sem, val) atomic_set(&((sem)->count), (val))
/*
* These two _must_ execute atomically wrt each other.
*
* This is trivially done with load_locked/store_cond,
* but on the x86 we need an external synchronizer.
* Currently this is just the global interrupt lock,
* bah. Go for a smaller spinlock some day.
*
* (On the other hand this shouldn't be in any critical
* path, so..)
*/
static inline void wake_one_more(struct semaphore * sem)
{
unsigned long flags;
save_flags(flags);
cli();
sem->waking++;
restore_flags(flags);
}
static inline int waking_non_zero(struct semaphore *sem, struct task_struct *tsk)
{
unsigned long flags;
int ret = 0;
save_flags(flags);
cli();
if (sem->waking > 0) {
sem->waking--;
ret = 1;
}
restore_flags(flags);
return ret;
}
#include <asm/proc/semaphore.h>
#endif
|
