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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
|
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1999, 2000 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
*/
#ifndef _ASM_SPINLOCK_H
#define _ASM_SPINLOCK_H
#include <linux/config.h>
#include <asm/war.h>
/*
* Your basic SMP spinlocks, allowing only a single CPU anywhere
*/
typedef struct {
volatile unsigned int lock;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} spinlock_t;
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
#define spin_lock_init(x) do { (x)->lock = 0; } while(0)
#define spin_is_locked(x) ((x)->lock != 0)
#define spin_unlock_wait(x) do { barrier(); } while ((x)->lock)
#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
/*
* 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.
*/
static inline void _raw_spin_lock(spinlock_t *lock)
{
unsigned int tmp;
if (R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set noreorder # _raw_spin_lock \n"
"1: ll %1, %2 \n"
" bnez %1, 1b \n"
" li %1, 1 \n"
" sc %1, %0 \n"
" beqzl %1, 1b \n"
" nop \n"
" sync \n"
" .set reorder \n"
: "=m" (lock->lock), "=&r" (tmp)
: "m" (lock->lock)
: "memory");
} else {
__asm__ __volatile__(
" .set noreorder # _raw_spin_lock \n"
"1: ll %1, %2 \n"
" bnez %1, 1b \n"
" li %1, 1 \n"
" sc %1, %0 \n"
" beqz %1, 1b \n"
" sync \n"
" .set reorder \n"
: "=m" (lock->lock), "=&r" (tmp)
: "m" (lock->lock)
: "memory");
}
}
static inline void _raw_spin_unlock(spinlock_t *lock)
{
__asm__ __volatile__(
" .set noreorder # _raw_spin_unlock \n"
" sync \n"
" sw $0, %0 \n"
" .set\treorder \n"
: "=m" (lock->lock)
: "m" (lock->lock)
: "memory");
}
static inline unsigned int _raw_spin_trylock(spinlock_t *lock)
{
unsigned int temp, res;
if (R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set noreorder # _raw_spin_trylock \n"
"1: ll %0, %3 \n"
" ori %2, %0, 1 \n"
" sc %2, %1 \n"
" beqzl %2, 1b \n"
" nop \n"
" andi %2, %0, 1 \n"
" sync \n"
" .set reorder"
: "=&r" (temp), "=m" (lock->lock), "=&r" (res)
: "m" (lock->lock)
: "memory");
} else {
__asm__ __volatile__(
" .set noreorder # _raw_spin_trylock \n"
"1: ll %0, %3 \n"
" ori %2, %0, 1 \n"
" sc %2, %1 \n"
" beqz %2, 1b \n"
" andi %2, %0, 1 \n"
" sync \n"
" .set reorder"
: "=&r" (temp), "=m" (lock->lock), "=&r" (res)
: "m" (lock->lock)
: "memory");
}
return res == 0;
}
/*
* Read-write spinlocks, allowing multiple readers but only one writer.
*
* NOTE! it is quite common to have readers in interrupts but no interrupt
* writers. For those circumstances we can "mix" irq-safe locks - any writer
* needs to get a irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
typedef struct {
volatile unsigned int lock;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
static inline void _raw_read_lock(rwlock_t *rw)
{
unsigned int tmp;
if (R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set noreorder # _raw_read_lock \n"
"1: ll %1, %2 \n"
" bltz %1, 1b \n"
" addu %1, 1 \n"
" sc %1, %0 \n"
" beqzl %1, 1b \n"
" nop \n"
" sync \n"
" .set reorder \n"
: "=m" (rw->lock), "=&r" (tmp)
: "m" (rw->lock)
: "memory");
} else {
__asm__ __volatile__(
" .set noreorder # _raw_read_lock \n"
"1: ll %1, %2 \n"
" bltz %1, 1b \n"
" addu %1, 1 \n"
" sc %1, %0 \n"
" beqz %1, 1b \n"
" sync \n"
" .set reorder \n"
: "=m" (rw->lock), "=&r" (tmp)
: "m" (rw->lock)
: "memory");
}
}
/* Note the use of sub, not subu which will make the kernel die with an
overflow exception if we ever try to unlock an rwlock that is already
unlocked or is being held by a writer. */
static inline void _raw_read_unlock(rwlock_t *rw)
{
unsigned int tmp;
if (R10000_LLSC_WAR) {
__asm__ __volatile__(
"1: ll %1, %2 # _raw_read_unlock \n"
" sub %1, 1 \n"
" sc %1, %0 \n"
" beqzl %1, 1b \n"
" sync \n"
: "=m" (rw->lock), "=&r" (tmp)
: "m" (rw->lock)
: "memory");
} else {
__asm__ __volatile__(
" .set noreorder # _raw_read_unlock \n"
"1: ll %1, %2 \n"
" sub %1, 1 \n"
" sc %1, %0 \n"
" beqz %1, 1b \n"
" sync \n"
" .set reorder \n"
: "=m" (rw->lock), "=&r" (tmp)
: "m" (rw->lock)
: "memory");
}
}
static inline void _raw_write_lock(rwlock_t *rw)
{
unsigned int tmp;
if (R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set noreorder # _raw_write_lock \n"
"1: ll %1, %2 \n"
" bnez %1, 1b \n"
" lui %1, 0x8000 \n"
" sc %1, %0 \n"
" beqzl %1, 1b \n"
" nop \n"
" sync \n"
" .set reorder \n"
: "=m" (rw->lock), "=&r" (tmp)
: "m" (rw->lock)
: "memory");
} else {
__asm__ __volatile__(
" .set noreorder # _raw_write_lock \n"
"1: ll %1, %2 \n"
" bnez %1, 1b \n"
" lui %1, 0x8000 \n"
" sc %1, %0 \n"
" beqz %1, 1b \n"
" nop \n"
" sync \n"
" .set reorder \n"
: "=m" (rw->lock), "=&r" (tmp)
: "m" (rw->lock)
: "memory");
}
}
static inline void _raw_write_unlock(rwlock_t *rw)
{
__asm__ __volatile__(
" sync # _raw_write_unlock \n"
" sw $0, %0 \n"
: "=m" (rw->lock)
: "m" (rw->lock)
: "memory");
}
#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
static inline int _raw_write_trylock(rwlock_t *rw)
{
unsigned int tmp;
int ret;
if (R10000_LLSC_WAR) {
__asm__ __volatile__(
" .set noreorder # _raw_write_trylock \n"
" li %2, 0 \n"
"1: ll %1, %3 \n"
" bnez %1, 2f \n"
" lui %1, 0x8000 \n"
" sc %1, %0 \n"
" beqzl %1, 1b \n"
" nop \n"
" sync \n"
" li %2, 1 \n"
" .set reorder \n"
"2: \n"
: "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
: "m" (rw->lock)
: "memory");
} else {
__asm__ __volatile__(
" .set noreorder # _raw_write_trylock \n"
" li %2, 0 \n"
"1: ll %1, %3 \n"
" bnez %1, 2f \n"
" lui %1, 0x8000 \n"
" sc %1, %0 \n"
" beqz %1, 1b \n"
" sync \n"
" li %2, 1 \n"
" .set reorder \n"
"2: \n"
: "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
: "m" (rw->lock)
: "memory");
}
return ret;
}
#endif /* _ASM_SPINLOCK_H */
|
