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1da177e4 LT |
1 | #ifndef __ASM_SPINLOCK_H |
2 | #define __ASM_SPINLOCK_H | |
88ced031 | 3 | #ifdef __KERNEL__ |
1da177e4 LT |
4 | |
5 | /* | |
6 | * Simple spin lock operations. | |
7 | * | |
8 | * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM | |
9 | * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM | |
10 | * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM | |
11 | * Rework to support virtual processors | |
12 | * | |
13 | * Type of int is used as a full 64b word is not necessary. | |
14 | * | |
15 | * This program is free software; you can redistribute it and/or | |
16 | * modify it under the terms of the GNU General Public License | |
17 | * as published by the Free Software Foundation; either version | |
18 | * 2 of the License, or (at your option) any later version. | |
fb1c8f93 IM |
19 | * |
20 | * (the type definitions are in asm/spinlock_types.h) | |
1da177e4 | 21 | */ |
945feb17 | 22 | #include <linux/irqflags.h> |
0212ddd8 | 23 | #ifdef CONFIG_PPC64 |
1da177e4 LT |
24 | #include <asm/paca.h> |
25 | #include <asm/hvcall.h> | |
1da44037 | 26 | #include <asm/iseries/hv_call.h> |
0212ddd8 PM |
27 | #endif |
28 | #include <asm/asm-compat.h> | |
29 | #include <asm/synch.h> | |
1da177e4 | 30 | |
fb1c8f93 | 31 | #define __raw_spin_is_locked(x) ((x)->slock != 0) |
1da177e4 | 32 | |
0212ddd8 PM |
33 | #ifdef CONFIG_PPC64 |
34 | /* use 0x800000yy when locked, where yy == CPU number */ | |
35 | #define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token)) | |
36 | #else | |
37 | #define LOCK_TOKEN 1 | |
38 | #endif | |
39 | ||
f007cacf PM |
40 | #if defined(CONFIG_PPC64) && defined(CONFIG_SMP) |
41 | #define CLEAR_IO_SYNC (get_paca()->io_sync = 0) | |
42 | #define SYNC_IO do { \ | |
43 | if (unlikely(get_paca()->io_sync)) { \ | |
44 | mb(); \ | |
45 | get_paca()->io_sync = 0; \ | |
46 | } \ | |
47 | } while (0) | |
48 | #else | |
49 | #define CLEAR_IO_SYNC | |
50 | #define SYNC_IO | |
51 | #endif | |
52 | ||
fb1c8f93 IM |
53 | /* |
54 | * This returns the old value in the lock, so we succeeded | |
55 | * in getting the lock if the return value is 0. | |
56 | */ | |
89b5810f | 57 | static inline unsigned long __spin_trylock(raw_spinlock_t *lock) |
fb1c8f93 | 58 | { |
0212ddd8 | 59 | unsigned long tmp, token; |
1da177e4 | 60 | |
0212ddd8 | 61 | token = LOCK_TOKEN; |
fb1c8f93 | 62 | __asm__ __volatile__( |
144b9c13 | 63 | "1: lwarx %0,0,%2\n\ |
fb1c8f93 IM |
64 | cmpwi 0,%0,0\n\ |
65 | bne- 2f\n\ | |
66 | stwcx. %1,0,%2\n\ | |
67 | bne- 1b\n\ | |
68 | isync\n\ | |
0212ddd8 PM |
69 | 2:" : "=&r" (tmp) |
70 | : "r" (token), "r" (&lock->slock) | |
fb1c8f93 | 71 | : "cr0", "memory"); |
1da177e4 | 72 | |
fb1c8f93 IM |
73 | return tmp; |
74 | } | |
1da177e4 | 75 | |
89b5810f | 76 | static inline int __raw_spin_trylock(raw_spinlock_t *lock) |
1da177e4 | 77 | { |
f007cacf | 78 | CLEAR_IO_SYNC; |
fb1c8f93 | 79 | return __spin_trylock(lock) == 0; |
1da177e4 LT |
80 | } |
81 | ||
82 | /* | |
83 | * On a system with shared processors (that is, where a physical | |
84 | * processor is multiplexed between several virtual processors), | |
85 | * there is no point spinning on a lock if the holder of the lock | |
86 | * isn't currently scheduled on a physical processor. Instead | |
87 | * we detect this situation and ask the hypervisor to give the | |
88 | * rest of our timeslice to the lock holder. | |
89 | * | |
90 | * So that we can tell which virtual processor is holding a lock, | |
91 | * we put 0x80000000 | smp_processor_id() in the lock when it is | |
92 | * held. Conveniently, we have a word in the paca that holds this | |
93 | * value. | |
94 | */ | |
95 | ||
96 | #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) | |
97 | /* We only yield to the hypervisor if we are in shared processor mode */ | |
3356bb9f | 98 | #define SHARED_PROCESSOR (get_lppaca()->shared_proc) |
fb1c8f93 IM |
99 | extern void __spin_yield(raw_spinlock_t *lock); |
100 | extern void __rw_yield(raw_rwlock_t *lock); | |
1da177e4 LT |
101 | #else /* SPLPAR || ISERIES */ |
102 | #define __spin_yield(x) barrier() | |
103 | #define __rw_yield(x) barrier() | |
104 | #define SHARED_PROCESSOR 0 | |
105 | #endif | |
1da177e4 | 106 | |
89b5810f | 107 | static inline void __raw_spin_lock(raw_spinlock_t *lock) |
1da177e4 | 108 | { |
f007cacf | 109 | CLEAR_IO_SYNC; |
1da177e4 LT |
110 | while (1) { |
111 | if (likely(__spin_trylock(lock) == 0)) | |
112 | break; | |
113 | do { | |
114 | HMT_low(); | |
115 | if (SHARED_PROCESSOR) | |
116 | __spin_yield(lock); | |
fb1c8f93 | 117 | } while (unlikely(lock->slock != 0)); |
1da177e4 LT |
118 | HMT_medium(); |
119 | } | |
120 | } | |
121 | ||
89b5810f BVA |
122 | static inline |
123 | void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags) | |
1da177e4 LT |
124 | { |
125 | unsigned long flags_dis; | |
126 | ||
f007cacf | 127 | CLEAR_IO_SYNC; |
1da177e4 LT |
128 | while (1) { |
129 | if (likely(__spin_trylock(lock) == 0)) | |
130 | break; | |
131 | local_save_flags(flags_dis); | |
132 | local_irq_restore(flags); | |
133 | do { | |
134 | HMT_low(); | |
135 | if (SHARED_PROCESSOR) | |
136 | __spin_yield(lock); | |
fb1c8f93 | 137 | } while (unlikely(lock->slock != 0)); |
1da177e4 LT |
138 | HMT_medium(); |
139 | local_irq_restore(flags_dis); | |
140 | } | |
141 | } | |
142 | ||
89b5810f | 143 | static inline void __raw_spin_unlock(raw_spinlock_t *lock) |
fb1c8f93 | 144 | { |
f007cacf | 145 | SYNC_IO; |
144b9c13 AB |
146 | __asm__ __volatile__("# __raw_spin_unlock\n\t" |
147 | LWSYNC_ON_SMP: : :"memory"); | |
fb1c8f93 IM |
148 | lock->slock = 0; |
149 | } | |
150 | ||
0212ddd8 | 151 | #ifdef CONFIG_PPC64 |
fb1c8f93 | 152 | extern void __raw_spin_unlock_wait(raw_spinlock_t *lock); |
0212ddd8 PM |
153 | #else |
154 | #define __raw_spin_unlock_wait(lock) \ | |
155 | do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0) | |
156 | #endif | |
fb1c8f93 | 157 | |
1da177e4 LT |
158 | /* |
159 | * Read-write spinlocks, allowing multiple readers | |
160 | * but only one writer. | |
161 | * | |
162 | * NOTE! it is quite common to have readers in interrupts | |
163 | * but no interrupt writers. For those circumstances we | |
164 | * can "mix" irq-safe locks - any writer needs to get a | |
165 | * irq-safe write-lock, but readers can get non-irqsafe | |
166 | * read-locks. | |
167 | */ | |
1da177e4 | 168 | |
fb1c8f93 IM |
169 | #define __raw_read_can_lock(rw) ((rw)->lock >= 0) |
170 | #define __raw_write_can_lock(rw) (!(rw)->lock) | |
1da177e4 | 171 | |
0212ddd8 PM |
172 | #ifdef CONFIG_PPC64 |
173 | #define __DO_SIGN_EXTEND "extsw %0,%0\n" | |
174 | #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ | |
175 | #else | |
176 | #define __DO_SIGN_EXTEND | |
177 | #define WRLOCK_TOKEN (-1) | |
178 | #endif | |
179 | ||
1da177e4 LT |
180 | /* |
181 | * This returns the old value in the lock + 1, | |
182 | * so we got a read lock if the return value is > 0. | |
183 | */ | |
89b5810f | 184 | static inline long __read_trylock(raw_rwlock_t *rw) |
1da177e4 LT |
185 | { |
186 | long tmp; | |
187 | ||
188 | __asm__ __volatile__( | |
144b9c13 | 189 | "1: lwarx %0,0,%1\n" |
0212ddd8 PM |
190 | __DO_SIGN_EXTEND |
191 | " addic. %0,%0,1\n\ | |
192 | ble- 2f\n" | |
193 | PPC405_ERR77(0,%1) | |
194 | " stwcx. %0,0,%1\n\ | |
1da177e4 LT |
195 | bne- 1b\n\ |
196 | isync\n\ | |
197 | 2:" : "=&r" (tmp) | |
198 | : "r" (&rw->lock) | |
199 | : "cr0", "xer", "memory"); | |
200 | ||
201 | return tmp; | |
202 | } | |
203 | ||
1da177e4 LT |
204 | /* |
205 | * This returns the old value in the lock, | |
206 | * so we got the write lock if the return value is 0. | |
207 | */ | |
89b5810f | 208 | static inline long __write_trylock(raw_rwlock_t *rw) |
1da177e4 | 209 | { |
0212ddd8 | 210 | long tmp, token; |
1da177e4 | 211 | |
0212ddd8 | 212 | token = WRLOCK_TOKEN; |
1da177e4 | 213 | __asm__ __volatile__( |
144b9c13 | 214 | "1: lwarx %0,0,%2\n\ |
1da177e4 | 215 | cmpwi 0,%0,0\n\ |
0212ddd8 PM |
216 | bne- 2f\n" |
217 | PPC405_ERR77(0,%1) | |
218 | " stwcx. %1,0,%2\n\ | |
1da177e4 LT |
219 | bne- 1b\n\ |
220 | isync\n\ | |
0212ddd8 PM |
221 | 2:" : "=&r" (tmp) |
222 | : "r" (token), "r" (&rw->lock) | |
1da177e4 LT |
223 | : "cr0", "memory"); |
224 | ||
225 | return tmp; | |
226 | } | |
227 | ||
89b5810f | 228 | static inline void __raw_read_lock(raw_rwlock_t *rw) |
1da177e4 | 229 | { |
fb1c8f93 IM |
230 | while (1) { |
231 | if (likely(__read_trylock(rw) > 0)) | |
232 | break; | |
233 | do { | |
234 | HMT_low(); | |
235 | if (SHARED_PROCESSOR) | |
236 | __rw_yield(rw); | |
237 | } while (unlikely(rw->lock < 0)); | |
238 | HMT_medium(); | |
239 | } | |
1da177e4 LT |
240 | } |
241 | ||
89b5810f | 242 | static inline void __raw_write_lock(raw_rwlock_t *rw) |
1da177e4 LT |
243 | { |
244 | while (1) { | |
245 | if (likely(__write_trylock(rw) == 0)) | |
246 | break; | |
247 | do { | |
248 | HMT_low(); | |
249 | if (SHARED_PROCESSOR) | |
250 | __rw_yield(rw); | |
d637413f | 251 | } while (unlikely(rw->lock != 0)); |
1da177e4 LT |
252 | HMT_medium(); |
253 | } | |
254 | } | |
255 | ||
89b5810f | 256 | static inline int __raw_read_trylock(raw_rwlock_t *rw) |
fb1c8f93 IM |
257 | { |
258 | return __read_trylock(rw) > 0; | |
259 | } | |
260 | ||
89b5810f | 261 | static inline int __raw_write_trylock(raw_rwlock_t *rw) |
fb1c8f93 IM |
262 | { |
263 | return __write_trylock(rw) == 0; | |
264 | } | |
265 | ||
89b5810f | 266 | static inline void __raw_read_unlock(raw_rwlock_t *rw) |
fb1c8f93 IM |
267 | { |
268 | long tmp; | |
269 | ||
270 | __asm__ __volatile__( | |
144b9c13 AB |
271 | "# read_unlock\n\t" |
272 | LWSYNC_ON_SMP | |
273 | "1: lwarx %0,0,%1\n\ | |
0212ddd8 PM |
274 | addic %0,%0,-1\n" |
275 | PPC405_ERR77(0,%1) | |
276 | " stwcx. %0,0,%1\n\ | |
fb1c8f93 IM |
277 | bne- 1b" |
278 | : "=&r"(tmp) | |
279 | : "r"(&rw->lock) | |
280 | : "cr0", "memory"); | |
281 | } | |
282 | ||
89b5810f | 283 | static inline void __raw_write_unlock(raw_rwlock_t *rw) |
fb1c8f93 | 284 | { |
144b9c13 AB |
285 | __asm__ __volatile__("# write_unlock\n\t" |
286 | LWSYNC_ON_SMP: : :"memory"); | |
fb1c8f93 IM |
287 | rw->lock = 0; |
288 | } | |
289 | ||
cdc39363 MS |
290 | #define _raw_spin_relax(lock) __spin_yield(lock) |
291 | #define _raw_read_relax(lock) __rw_yield(lock) | |
292 | #define _raw_write_relax(lock) __rw_yield(lock) | |
ef6edc97 | 293 | |
88ced031 | 294 | #endif /* __KERNEL__ */ |
1da177e4 | 295 | #endif /* __ASM_SPINLOCK_H */ |