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
167
168
169
170
171
|
/* spinlock.h: 64-bit Sparc spinlock support.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
*/
#ifndef __SPARC64_SPINLOCK_H
#define __SPARC64_SPINLOCK_H
#ifndef __ASSEMBLY__
/* To get debugging spinlocks which detect and catch
* deadlock situations, set DEBUG_SPINLOCKS in the sparc64
* specific makefile and rebuild your kernel.
*/
/* All of these locking primitives are expected to work properly
* even in an RMO memory model, which currently is what the kernel
* runs in.
*
* There is another issue. Because we play games to save cycles
* in the non-contention case, we need to be extra careful about
* branch targets into the "spinning" code. They live in their
* own section, but the newer V9 branches have a shorter range
* than the traditional 32-bit sparc branch variants. The rule
* is that the branches that go into and out of the spinner sections
* must be pre-V9 branches.
*/
#ifndef SPIN_LOCK_DEBUG
typedef unsigned char spinlock_t;
#define SPIN_LOCK_UNLOCKED 0
#define spin_lock_init(lock) (*((unsigned char *)(lock)) = 0)
#define spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
#define spin_unlock_wait(lock) \
do { membar("#LoadLoad"); \
} while(*((volatile unsigned char *)lock))
extern __inline__ void spin_lock(spinlock_t *lock)
{
__asm__ __volatile__(
"1: ldstub [%0], %%g7\n"
" brnz,pn %%g7, 2f\n"
" membar #StoreLoad | #StoreStore\n"
" .subsection 2\n"
"2: ldub [%0], %%g7\n"
" brnz,pt %%g7, 2b\n"
" membar #LoadLoad\n"
" b,a,pt %%xcc, 1b\n"
" .previous\n"
: /* no outputs */
: "r" (lock)
: "g7", "memory");
}
extern __inline__ int spin_trylock(spinlock_t *lock)
{
unsigned int result;
__asm__ __volatile__("ldstub [%1], %0\n\t"
"membar #StoreLoad | #StoreStore"
: "=r" (result)
: "r" (lock)
: "memory");
return (result == 0);
}
extern __inline__ void spin_unlock(spinlock_t *lock)
{
__asm__ __volatile__("membar #StoreStore | #LoadStore\n\t"
"stb %%g0, [%0]"
: /* No outputs */
: "r" (lock)
: "memory");
}
#else /* !(SPIN_LOCK_DEBUG) */
typedef struct {
unsigned char lock;
unsigned int owner_pc, owner_cpu;
} spinlock_t;
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
#define spin_lock_init(__lock) \
do { (__lock)->lock = 0; \
(__lock)->owner_pc = 0; \
(__lock)->owner_cpu = 0xff; \
} while(0)
#define spin_is_locked(__lock) (*((volatile unsigned char *)(&((__lock)->lock))) != 0)
#define spin_unlock_wait(__lock) \
do { \
membar("#LoadLoad"); \
} while(*((volatile unsigned char *)(&((__lock)->lock))))
extern void _do_spin_lock (spinlock_t *lock, char *str);
extern void _do_spin_unlock (spinlock_t *lock);
extern int _spin_trylock (spinlock_t *lock);
#define spin_trylock(lp) _spin_trylock(lp)
#define spin_lock(lock) _do_spin_lock(lock, "spin_lock")
#define spin_unlock(lock) _do_spin_unlock(lock)
#endif /* SPIN_LOCK_DEBUG */
/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
#ifndef SPIN_LOCK_DEBUG
typedef unsigned int rwlock_t;
#define RW_LOCK_UNLOCKED 0
#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
extern void __read_lock(rwlock_t *);
extern void __read_unlock(rwlock_t *);
extern void __write_lock(rwlock_t *);
extern void __write_unlock(rwlock_t *);
#define read_lock(p) __read_lock(p)
#define read_unlock(p) __read_unlock(p)
#define write_lock(p) __write_lock(p)
#define write_unlock(p) __write_unlock(p)
#else /* !(SPIN_LOCK_DEBUG) */
typedef struct {
unsigned long lock;
unsigned int writer_pc, writer_cpu;
unsigned int reader_pc[4];
} rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, 0xff, { 0, 0, 0, 0 } }
#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
extern void _do_read_lock(rwlock_t *rw, char *str);
extern void _do_read_unlock(rwlock_t *rw, char *str);
extern void _do_write_lock(rwlock_t *rw, char *str);
extern void _do_write_unlock(rwlock_t *rw);
#define read_lock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_read_lock(lock, "read_lock"); \
__restore_flags(flags); \
} while(0)
#define read_unlock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_read_unlock(lock, "read_unlock"); \
__restore_flags(flags); \
} while(0)
#define write_lock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_write_lock(lock, "write_lock"); \
__restore_flags(flags); \
} while(0)
#define write_unlock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_write_unlock(lock); \
__restore_flags(flags); \
} while(0)
#endif /* SPIN_LOCK_DEBUG */
#endif /* !(__ASSEMBLY__) */
#endif /* !(__SPARC64_SPINLOCK_H) */
|
