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
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
#ifndef _ALPHA_SPINLOCK_H
#define _ALPHA_SPINLOCK_H
#include <asm/system.h>
#include <linux/kernel.h>
#include <asm/current.h>
#define DEBUG_SPINLOCK 0
#define DEBUG_RWLOCK 0
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
* on the local processor, one does not.
*
* We make no fairness assumptions. They have a cost.
*/
typedef struct {
volatile unsigned int lock /*__attribute__((aligned(32))) */;
#if DEBUG_SPINLOCK
int on_cpu;
int line_no;
void *previous;
struct task_struct * task;
const char *base_file;
#endif
} spinlock_t;
#if DEBUG_SPINLOCK
#define SPIN_LOCK_UNLOCKED (spinlock_t) {0, -1, 0, 0, 0, 0}
#define spin_lock_init(x) \
((x)->lock = 0, (x)->on_cpu = -1, (x)->previous = 0, (x)->task = 0)
#else
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
#define spin_lock_init(x) ((x)->lock = 0)
#endif
#define spin_is_locked(x) ((x)->lock != 0)
#define spin_unlock_wait(x) ({ do { barrier(); } while ((x)->lock); })
#if DEBUG_SPINLOCK
extern void spin_unlock(spinlock_t * lock);
extern void debug_spin_lock(spinlock_t * lock, const char *, int);
extern int debug_spin_trylock(spinlock_t * lock, const char *, int);
#define spin_lock(LOCK) debug_spin_lock(LOCK, __BASE_FILE__, __LINE__)
#define spin_trylock(LOCK) debug_spin_trylock(LOCK, __BASE_FILE__, __LINE__)
#define spin_lock_own(LOCK, LOCATION) \
do { \
if (!((LOCK)->lock && (LOCK)->on_cpu == smp_processor_id())) \
printk("%s: called on %d from %p but lock %s on %d\n", \
LOCATION, smp_processor_id(), \
__builtin_return_address(0), \
(LOCK)->lock ? "taken" : "freed", (LOCK)->on_cpu); \
} while (0)
#else
static inline void spin_unlock(spinlock_t * lock)
{
mb();
lock->lock = 0;
}
static inline void spin_lock(spinlock_t * lock)
{
long tmp;
/* Use sub-sections to put the actual loop at the end
of this object file's text section so as to perfect
branch prediction. */
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" blbs %0,2f\n"
" or %0,1,%0\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
" mb\n"
".subsection 2\n"
"2: ldl %0,%1\n"
" blbs %0,2b\n"
" br 1b\n"
".previous"
: "=r" (tmp), "=m" (lock->lock)
: "m"(lock->lock) : "memory");
}
#define spin_trylock(lock) (!test_and_set_bit(0,(lock)))
#define spin_lock_own(LOCK, LOCATION) ((void)0)
#endif /* DEBUG_SPINLOCK */
/***********************************************************/
typedef struct {
volatile int write_lock:1, read_counter:31;
} /*__attribute__((aligned(32)))*/ rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
#if DEBUG_RWLOCK
extern void write_lock(rwlock_t * lock);
extern void read_lock(rwlock_t * lock);
#else
static inline void write_lock(rwlock_t * lock)
{
long regx;
__asm__ __volatile__(
"1: ldl_l %1,%0\n"
" bne %1,6f\n"
" or $31,1,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
" mb\n"
".subsection 2\n"
"6: ldl %1,%0\n"
" bne %1,6b\n"
" br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx)
: "0" (*(volatile int *)lock) : "memory");
}
static inline void read_lock(rwlock_t * lock)
{
long regx;
__asm__ __volatile__(
"1: ldl_l %1,%0\n"
" blbs %1,6f\n"
" subl %1,2,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
"4: mb\n"
".subsection 2\n"
"6: ldl %1,%0\n"
" blbs %1,6b\n"
" br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx)
: "m" (*(volatile int *)lock) : "memory");
}
#endif /* DEBUG_RWLOCK */
static inline void write_unlock(rwlock_t * lock)
{
mb();
*(volatile int *)lock = 0;
}
static inline void read_unlock(rwlock_t * lock)
{
long regx;
__asm__ __volatile__(
" mb\n"
"1: ldl_l %1,%0\n"
" addl %1,2,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
".subsection 2\n"
"6: br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx)
: "m" (*(volatile int *)lock) : "memory");
}
#endif /* _ALPHA_SPINLOCK_H */
|
