spinlock.h (fb3a6bbc912b12347614e5742c7c61416cdb0ca0) spinlock.h (e5931943d02bf751b1ec849c0d2ade23d76a8d41)
1#ifndef __ASM_SPINLOCK_H
2#define __ASM_SPINLOCK_H
3#ifdef __KERNEL__
4
5/*
6 * Simple spin lock operations.
7 *
8 * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM

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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 */
168
1#ifndef __ASM_SPINLOCK_H
2#define __ASM_SPINLOCK_H
3#ifdef __KERNEL__
4
5/*
6 * Simple spin lock operations.
7 *
8 * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM

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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 */
168
169#define __raw_read_can_lock(rw) ((rw)->lock >= 0)
170#define __raw_write_can_lock(rw) (!(rw)->lock)
169#define arch_read_can_lock(rw) ((rw)->lock >= 0)
170#define arch_write_can_lock(rw) (!(rw)->lock)
171
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
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 */
171
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
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 */
184static inline long arch_read_trylock(arch_rwlock_t *rw)
184static inline long __arch_read_trylock(arch_rwlock_t *rw)
185{
186 long tmp;
187
188 __asm__ __volatile__(
189"1: lwarx %0,0,%1\n"
190 __DO_SIGN_EXTEND
191" addic. %0,%0,1\n\
192 ble- 2f\n"

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200
201 return tmp;
202}
203
204/*
205 * This returns the old value in the lock,
206 * so we got the write lock if the return value is 0.
207 */
185{
186 long tmp;
187
188 __asm__ __volatile__(
189"1: lwarx %0,0,%1\n"
190 __DO_SIGN_EXTEND
191" addic. %0,%0,1\n\
192 ble- 2f\n"

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200
201 return tmp;
202}
203
204/*
205 * This returns the old value in the lock,
206 * so we got the write lock if the return value is 0.
207 */
208static inline long arch_write_trylock(arch_rwlock_t *rw)
208static inline long __arch_write_trylock(arch_rwlock_t *rw)
209{
210 long tmp, token;
211
212 token = WRLOCK_TOKEN;
213 __asm__ __volatile__(
214"1: lwarx %0,0,%2\n\
215 cmpwi 0,%0,0\n\
216 bne- 2f\n"
217 PPC405_ERR77(0,%1)
218" stwcx. %1,0,%2\n\
219 bne- 1b\n\
220 isync\n\
2212:" : "=&r" (tmp)
222 : "r" (token), "r" (&rw->lock)
223 : "cr0", "memory");
224
225 return tmp;
226}
227
209{
210 long tmp, token;
211
212 token = WRLOCK_TOKEN;
213 __asm__ __volatile__(
214"1: lwarx %0,0,%2\n\
215 cmpwi 0,%0,0\n\
216 bne- 2f\n"
217 PPC405_ERR77(0,%1)
218" stwcx. %1,0,%2\n\
219 bne- 1b\n\
220 isync\n\
2212:" : "=&r" (tmp)
222 : "r" (token), "r" (&rw->lock)
223 : "cr0", "memory");
224
225 return tmp;
226}
227
228static inline void __raw_read_lock(arch_rwlock_t *rw)
228static inline void arch_read_lock(arch_rwlock_t *rw)
229{
230 while (1) {
229{
230 while (1) {
231 if (likely(arch_read_trylock(rw) > 0))
231 if (likely(__arch_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 }
240}
241
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 }
240}
241
242static inline void __raw_write_lock(arch_rwlock_t *rw)
242static inline void arch_write_lock(arch_rwlock_t *rw)
243{
244 while (1) {
243{
244 while (1) {
245 if (likely(arch_write_trylock(rw) == 0))
245 if (likely(__arch_write_trylock(rw) == 0))
246 break;
247 do {
248 HMT_low();
249 if (SHARED_PROCESSOR)
250 __rw_yield(rw);
251 } while (unlikely(rw->lock != 0));
252 HMT_medium();
253 }
254}
255
246 break;
247 do {
248 HMT_low();
249 if (SHARED_PROCESSOR)
250 __rw_yield(rw);
251 } while (unlikely(rw->lock != 0));
252 HMT_medium();
253 }
254}
255
256static inline int __raw_read_trylock(arch_rwlock_t *rw)
256static inline int arch_read_trylock(arch_rwlock_t *rw)
257{
257{
258 return arch_read_trylock(rw) > 0;
258 return __arch_read_trylock(rw) > 0;
259}
260
259}
260
261static inline int __raw_write_trylock(arch_rwlock_t *rw)
261static inline int arch_write_trylock(arch_rwlock_t *rw)
262{
262{
263 return arch_write_trylock(rw) == 0;
263 return __arch_write_trylock(rw) == 0;
264}
265
264}
265
266static inline void __raw_read_unlock(arch_rwlock_t *rw)
266static inline void arch_read_unlock(arch_rwlock_t *rw)
267{
268 long tmp;
269
270 __asm__ __volatile__(
271 "# read_unlock\n\t"
272 LWSYNC_ON_SMP
273"1: lwarx %0,0,%1\n\
274 addic %0,%0,-1\n"
275 PPC405_ERR77(0,%1)
276" stwcx. %0,0,%1\n\
277 bne- 1b"
278 : "=&r"(tmp)
279 : "r"(&rw->lock)
280 : "cr0", "xer", "memory");
281}
282
267{
268 long tmp;
269
270 __asm__ __volatile__(
271 "# read_unlock\n\t"
272 LWSYNC_ON_SMP
273"1: lwarx %0,0,%1\n\
274 addic %0,%0,-1\n"
275 PPC405_ERR77(0,%1)
276" stwcx. %0,0,%1\n\
277 bne- 1b"
278 : "=&r"(tmp)
279 : "r"(&rw->lock)
280 : "cr0", "xer", "memory");
281}
282
283static inline void __raw_write_unlock(arch_rwlock_t *rw)
283static inline void arch_write_unlock(arch_rwlock_t *rw)
284{
285 __asm__ __volatile__("# write_unlock\n\t"
286 LWSYNC_ON_SMP: : :"memory");
287 rw->lock = 0;
288}
289
284{
285 __asm__ __volatile__("# write_unlock\n\t"
286 LWSYNC_ON_SMP: : :"memory");
287 rw->lock = 0;
288}
289
290#define __raw_read_lock_flags(lock, flags) __raw_read_lock(lock)
291#define __raw_write_lock_flags(lock, flags) __raw_write_lock(lock)
290#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
291#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
292
293#define arch_spin_relax(lock) __spin_yield(lock)
294#define arch_read_relax(lock) __rw_yield(lock)
295#define arch_write_relax(lock) __rw_yield(lock)
296
297#endif /* __KERNEL__ */
298#endif /* __ASM_SPINLOCK_H */
292
293#define arch_spin_relax(lock) __spin_yield(lock)
294#define arch_read_relax(lock) __rw_yield(lock)
295#define arch_write_relax(lock) __rw_yield(lock)
296
297#endif /* __KERNEL__ */
298#endif /* __ASM_SPINLOCK_H */