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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 | */ | |
57 | static __inline__ unsigned long __spin_trylock(raw_spinlock_t *lock) | |
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 | |
fb1c8f93 | 76 | static int __inline__ __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 | |
fb1c8f93 | 107 | static void __inline__ __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 | ||
fb1c8f93 | 122 | static void __inline__ __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags) |
1da177e4 LT |
123 | { |
124 | unsigned long flags_dis; | |
125 | ||
f007cacf | 126 | CLEAR_IO_SYNC; |
1da177e4 LT |
127 | while (1) { |
128 | if (likely(__spin_trylock(lock) == 0)) | |
129 | break; | |
130 | local_save_flags(flags_dis); | |
131 | local_irq_restore(flags); | |
132 | do { | |
133 | HMT_low(); | |
134 | if (SHARED_PROCESSOR) | |
135 | __spin_yield(lock); | |
fb1c8f93 | 136 | } while (unlikely(lock->slock != 0)); |
1da177e4 LT |
137 | HMT_medium(); |
138 | local_irq_restore(flags_dis); | |
139 | } | |
140 | } | |
141 | ||
fb1c8f93 IM |
142 | static __inline__ void __raw_spin_unlock(raw_spinlock_t *lock) |
143 | { | |
f007cacf | 144 | SYNC_IO; |
144b9c13 AB |
145 | __asm__ __volatile__("# __raw_spin_unlock\n\t" |
146 | LWSYNC_ON_SMP: : :"memory"); | |
fb1c8f93 IM |
147 | lock->slock = 0; |
148 | } | |
149 | ||
0212ddd8 | 150 | #ifdef CONFIG_PPC64 |
fb1c8f93 | 151 | extern void __raw_spin_unlock_wait(raw_spinlock_t *lock); |
0212ddd8 PM |
152 | #else |
153 | #define __raw_spin_unlock_wait(lock) \ | |
154 | do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0) | |
155 | #endif | |
fb1c8f93 | 156 | |
1da177e4 LT |
157 | /* |
158 | * Read-write spinlocks, allowing multiple readers | |
159 | * but only one writer. | |
160 | * | |
161 | * NOTE! it is quite common to have readers in interrupts | |
162 | * but no interrupt writers. For those circumstances we | |
163 | * can "mix" irq-safe locks - any writer needs to get a | |
164 | * irq-safe write-lock, but readers can get non-irqsafe | |
165 | * read-locks. | |
166 | */ | |
1da177e4 | 167 | |
fb1c8f93 IM |
168 | #define __raw_read_can_lock(rw) ((rw)->lock >= 0) |
169 | #define __raw_write_can_lock(rw) (!(rw)->lock) | |
1da177e4 | 170 | |
0212ddd8 PM |
171 | #ifdef CONFIG_PPC64 |
172 | #define __DO_SIGN_EXTEND "extsw %0,%0\n" | |
173 | #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ | |
174 | #else | |
175 | #define __DO_SIGN_EXTEND | |
176 | #define WRLOCK_TOKEN (-1) | |
177 | #endif | |
178 | ||
1da177e4 LT |
179 | /* |
180 | * This returns the old value in the lock + 1, | |
181 | * so we got a read lock if the return value is > 0. | |
182 | */ | |
fb1c8f93 | 183 | static long __inline__ __read_trylock(raw_rwlock_t *rw) |
1da177e4 LT |
184 | { |
185 | long tmp; | |
186 | ||
187 | __asm__ __volatile__( | |
144b9c13 | 188 | "1: lwarx %0,0,%1\n" |
0212ddd8 PM |
189 | __DO_SIGN_EXTEND |
190 | " addic. %0,%0,1\n\ | |
191 | ble- 2f\n" | |
192 | PPC405_ERR77(0,%1) | |
193 | " stwcx. %0,0,%1\n\ | |
1da177e4 LT |
194 | bne- 1b\n\ |
195 | isync\n\ | |
196 | 2:" : "=&r" (tmp) | |
197 | : "r" (&rw->lock) | |
198 | : "cr0", "xer", "memory"); | |
199 | ||
200 | return tmp; | |
201 | } | |
202 | ||
1da177e4 LT |
203 | /* |
204 | * This returns the old value in the lock, | |
205 | * so we got the write lock if the return value is 0. | |
206 | */ | |
fb1c8f93 | 207 | static __inline__ long __write_trylock(raw_rwlock_t *rw) |
1da177e4 | 208 | { |
0212ddd8 | 209 | long tmp, token; |
1da177e4 | 210 | |
0212ddd8 | 211 | token = WRLOCK_TOKEN; |
1da177e4 | 212 | __asm__ __volatile__( |
144b9c13 | 213 | "1: lwarx %0,0,%2\n\ |
1da177e4 | 214 | cmpwi 0,%0,0\n\ |
0212ddd8 PM |
215 | bne- 2f\n" |
216 | PPC405_ERR77(0,%1) | |
217 | " stwcx. %1,0,%2\n\ | |
1da177e4 LT |
218 | bne- 1b\n\ |
219 | isync\n\ | |
0212ddd8 PM |
220 | 2:" : "=&r" (tmp) |
221 | : "r" (token), "r" (&rw->lock) | |
1da177e4 LT |
222 | : "cr0", "memory"); |
223 | ||
224 | return tmp; | |
225 | } | |
226 | ||
fb1c8f93 | 227 | static void __inline__ __raw_read_lock(raw_rwlock_t *rw) |
1da177e4 | 228 | { |
fb1c8f93 IM |
229 | while (1) { |
230 | if (likely(__read_trylock(rw) > 0)) | |
231 | break; | |
232 | do { | |
233 | HMT_low(); | |
234 | if (SHARED_PROCESSOR) | |
235 | __rw_yield(rw); | |
236 | } while (unlikely(rw->lock < 0)); | |
237 | HMT_medium(); | |
238 | } | |
1da177e4 LT |
239 | } |
240 | ||
fb1c8f93 | 241 | static void __inline__ __raw_write_lock(raw_rwlock_t *rw) |
1da177e4 LT |
242 | { |
243 | while (1) { | |
244 | if (likely(__write_trylock(rw) == 0)) | |
245 | break; | |
246 | do { | |
247 | HMT_low(); | |
248 | if (SHARED_PROCESSOR) | |
249 | __rw_yield(rw); | |
d637413f | 250 | } while (unlikely(rw->lock != 0)); |
1da177e4 LT |
251 | HMT_medium(); |
252 | } | |
253 | } | |
254 | ||
fb1c8f93 IM |
255 | static int __inline__ __raw_read_trylock(raw_rwlock_t *rw) |
256 | { | |
257 | return __read_trylock(rw) > 0; | |
258 | } | |
259 | ||
260 | static int __inline__ __raw_write_trylock(raw_rwlock_t *rw) | |
261 | { | |
262 | return __write_trylock(rw) == 0; | |
263 | } | |
264 | ||
265 | static void __inline__ __raw_read_unlock(raw_rwlock_t *rw) | |
266 | { | |
267 | long tmp; | |
268 | ||
269 | __asm__ __volatile__( | |
144b9c13 AB |
270 | "# read_unlock\n\t" |
271 | LWSYNC_ON_SMP | |
272 | "1: lwarx %0,0,%1\n\ | |
0212ddd8 PM |
273 | addic %0,%0,-1\n" |
274 | PPC405_ERR77(0,%1) | |
275 | " stwcx. %0,0,%1\n\ | |
fb1c8f93 IM |
276 | bne- 1b" |
277 | : "=&r"(tmp) | |
278 | : "r"(&rw->lock) | |
279 | : "cr0", "memory"); | |
280 | } | |
281 | ||
282 | static __inline__ void __raw_write_unlock(raw_rwlock_t *rw) | |
283 | { | |
144b9c13 AB |
284 | __asm__ __volatile__("# write_unlock\n\t" |
285 | LWSYNC_ON_SMP: : :"memory"); | |
fb1c8f93 IM |
286 | rw->lock = 0; |
287 | } | |
288 | ||
cdc39363 MS |
289 | #define _raw_spin_relax(lock) __spin_yield(lock) |
290 | #define _raw_read_relax(lock) __rw_yield(lock) | |
291 | #define _raw_write_relax(lock) __rw_yield(lock) | |
ef6edc97 | 292 | |
88ced031 | 293 | #endif /* __KERNEL__ */ |
1da177e4 | 294 | #endif /* __ASM_SPINLOCK_H */ |