Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1#ifndef _ALPHA_SPINLOCK_H
2#define _ALPHA_SPINLOCK_H
3
4#include <linux/kernel.h>
5#include <asm/current.h>
6#include <asm/barrier.h>
7#include <asm/processor.h>
8
9/*
10 * Simple spin lock operations. There are two variants, one clears IRQ's
11 * on the local processor, one does not.
12 *
13 * We make no fairness assumptions. They have a cost.
14 */
15
16#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
17#define arch_spin_is_locked(x) ((x)->lock != 0)
18
19static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
20{
21 smp_cond_load_acquire(&lock->lock, !VAL);
22}
23
24static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
25{
26 return lock.lock == 0;
27}
28
29static inline void arch_spin_unlock(arch_spinlock_t * lock)
30{
31 mb();
32 lock->lock = 0;
33}
34
35static inline void arch_spin_lock(arch_spinlock_t * lock)
36{
37 long tmp;
38
39 __asm__ __volatile__(
40 "1: ldl_l %0,%1\n"
41 " bne %0,2f\n"
42 " lda %0,1\n"
43 " stl_c %0,%1\n"
44 " beq %0,2f\n"
45 " mb\n"
46 ".subsection 2\n"
47 "2: ldl %0,%1\n"
48 " bne %0,2b\n"
49 " br 1b\n"
50 ".previous"
51 : "=&r" (tmp), "=m" (lock->lock)
52 : "m"(lock->lock) : "memory");
53}
54
55static inline int arch_spin_trylock(arch_spinlock_t *lock)
56{
57 return !test_and_set_bit(0, &lock->lock);
58}
59
60/***********************************************************/
61
62static inline int arch_read_can_lock(arch_rwlock_t *lock)
63{
64 return (lock->lock & 1) == 0;
65}
66
67static inline int arch_write_can_lock(arch_rwlock_t *lock)
68{
69 return lock->lock == 0;
70}
71
72static inline void arch_read_lock(arch_rwlock_t *lock)
73{
74 long regx;
75
76 __asm__ __volatile__(
77 "1: ldl_l %1,%0\n"
78 " blbs %1,6f\n"
79 " subl %1,2,%1\n"
80 " stl_c %1,%0\n"
81 " beq %1,6f\n"
82 " mb\n"
83 ".subsection 2\n"
84 "6: ldl %1,%0\n"
85 " blbs %1,6b\n"
86 " br 1b\n"
87 ".previous"
88 : "=m" (*lock), "=&r" (regx)
89 : "m" (*lock) : "memory");
90}
91
92static inline void arch_write_lock(arch_rwlock_t *lock)
93{
94 long regx;
95
96 __asm__ __volatile__(
97 "1: ldl_l %1,%0\n"
98 " bne %1,6f\n"
99 " lda %1,1\n"
100 " stl_c %1,%0\n"
101 " beq %1,6f\n"
102 " mb\n"
103 ".subsection 2\n"
104 "6: ldl %1,%0\n"
105 " bne %1,6b\n"
106 " br 1b\n"
107 ".previous"
108 : "=m" (*lock), "=&r" (regx)
109 : "m" (*lock) : "memory");
110}
111
112static inline int arch_read_trylock(arch_rwlock_t * lock)
113{
114 long regx;
115 int success;
116
117 __asm__ __volatile__(
118 "1: ldl_l %1,%0\n"
119 " lda %2,0\n"
120 " blbs %1,2f\n"
121 " subl %1,2,%2\n"
122 " stl_c %2,%0\n"
123 " beq %2,6f\n"
124 "2: mb\n"
125 ".subsection 2\n"
126 "6: br 1b\n"
127 ".previous"
128 : "=m" (*lock), "=&r" (regx), "=&r" (success)
129 : "m" (*lock) : "memory");
130
131 return success;
132}
133
134static inline int arch_write_trylock(arch_rwlock_t * lock)
135{
136 long regx;
137 int success;
138
139 __asm__ __volatile__(
140 "1: ldl_l %1,%0\n"
141 " lda %2,0\n"
142 " bne %1,2f\n"
143 " lda %2,1\n"
144 " stl_c %2,%0\n"
145 " beq %2,6f\n"
146 "2: mb\n"
147 ".subsection 2\n"
148 "6: br 1b\n"
149 ".previous"
150 : "=m" (*lock), "=&r" (regx), "=&r" (success)
151 : "m" (*lock) : "memory");
152
153 return success;
154}
155
156static inline void arch_read_unlock(arch_rwlock_t * lock)
157{
158 long regx;
159 __asm__ __volatile__(
160 " mb\n"
161 "1: ldl_l %1,%0\n"
162 " addl %1,2,%1\n"
163 " stl_c %1,%0\n"
164 " beq %1,6f\n"
165 ".subsection 2\n"
166 "6: br 1b\n"
167 ".previous"
168 : "=m" (*lock), "=&r" (regx)
169 : "m" (*lock) : "memory");
170}
171
172static inline void arch_write_unlock(arch_rwlock_t * lock)
173{
174 mb();
175 lock->lock = 0;
176}
177
178#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
179#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
180
181#endif /* _ALPHA_SPINLOCK_H */