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
|
/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
* Machine-dependent simple locks for the i386.
*/
#ifndef _I386_LOCK_H_
#define _I386_LOCK_H_
#if NCPUS > 1
#include <i386/smp.h>
/*
* All of the locking routines are built from calls on
* a locked-exchange operation. Values of the lock are
* 0 for unlocked, 1 for locked.
*/
#ifdef __GNUC__
/*
* The code here depends on the GNU C compiler.
*/
#define _simple_lock_xchg_(lock, new_val) \
({ int _old_val_; \
asm volatile("xchgl %0, %2" \
: "=r" (_old_val_) \
: "0" (new_val), "m" (*(lock)) : "memory" \
); \
_old_val_; \
})
#define simple_lock_init(l) \
((l)->lock_data = 0)
#define SIMPLE_LOCK_INITIALIZER(l) \
{.lock_data = 0}
#define simple_lock(l) \
({ \
while(_simple_lock_xchg_(l, 1)) \
while (*(volatile int *)&(l)->lock_data) \
cpu_pause(); \
0; \
})
#define simple_unlock(l) \
(_simple_lock_xchg_(l, 0))
#define simple_lock_try(l) \
(!_simple_lock_xchg_(l, 1))
/*
* General bit-lock routines.
*/
#define bit_lock(bit, l) \
({ \
asm volatile(" jmp 1f \n\
0: btl %0, %1 \n\
jb 0b \n\
1: lock \n\
btsl %0, %1 \n\
jb 0b" \
: \
: "r" (bit), "m" (*(volatile int *)(l)) : "memory"); \
0; \
})
#define bit_unlock(bit, l) \
({ \
asm volatile(" lock \n\
btrl %0, %1" \
: \
: "r" (bit), "m" (*(volatile int *)(l)) : "memory"); \
0; \
})
/*
* Set or clear individual bits in a long word.
* The locked access is needed only to lock access
* to the word, not to individual bits.
*/
#define i_bit_set(bit, l) \
({ \
asm volatile(" lock \n\
btsl %0, %1" \
: \
: "r" (bit), "m" (*(l)) ); \
0; \
})
#define i_bit_clear(bit, l) \
({ \
asm volatile(" lock \n\
btrl %0, %1" \
: \
: "r" (bit), "m" (*(l)) ); \
0; \
})
#endif /* __GNUC__ */
extern void simple_lock_pause(void);
#endif /* NCPUS > 1 */
#endif /* _I386_LOCK_H_ */
|
