diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-08-15 20:19:40 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-08-15 20:19:40 +0400 |
commit | 024b246ed24492d6c2ee14c34d742b137fce1b94 (patch) | |
tree | 428444950025503218c96b03c86f749403626dec /arch/alpha/include/asm/rwsem.h | |
parent | 9419fc1c957d600093baaea247fef23cca3b4e93 (diff) | |
download | linux-024b246ed24492d6c2ee14c34d742b137fce1b94.tar.xz |
alpha: move include/asm-alpha to arch/alpha/include/asm
Sam Ravnborg did the build-test that the direct header file move works,
I'm just committing it.
This is a pure move:
mkdir arch/alpha/include
git mv include/asm-alpha arch/alpha/include/asm
with no other changes.
Requested-and-tested-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha/include/asm/rwsem.h')
-rw-r--r-- | arch/alpha/include/asm/rwsem.h | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/rwsem.h b/arch/alpha/include/asm/rwsem.h new file mode 100644 index 000000000000..1570c0b54336 --- /dev/null +++ b/arch/alpha/include/asm/rwsem.h @@ -0,0 +1,259 @@ +#ifndef _ALPHA_RWSEM_H +#define _ALPHA_RWSEM_H + +/* + * Written by Ivan Kokshaysky <ink@jurassic.park.msu.ru>, 2001. + * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h + */ + +#ifndef _LINUX_RWSEM_H +#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" +#endif + +#ifdef __KERNEL__ + +#include <linux/compiler.h> +#include <linux/list.h> +#include <linux/spinlock.h> + +struct rwsem_waiter; + +extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); +extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); +extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *); +extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); + +/* + * the semaphore definition + */ +struct rw_semaphore { + long count; +#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L +#define RWSEM_ACTIVE_BIAS 0x0000000000000001L +#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL +#define RWSEM_WAITING_BIAS (-0x0000000100000000L) +#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS +#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) + spinlock_t wait_lock; + struct list_head wait_list; +}; + +#define __RWSEM_INITIALIZER(name) \ + { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \ + LIST_HEAD_INIT((name).wait_list) } + +#define DECLARE_RWSEM(name) \ + struct rw_semaphore name = __RWSEM_INITIALIZER(name) + +static inline void init_rwsem(struct rw_semaphore *sem) +{ + sem->count = RWSEM_UNLOCKED_VALUE; + spin_lock_init(&sem->wait_lock); + INIT_LIST_HEAD(&sem->wait_list); +} + +static inline void __down_read(struct rw_semaphore *sem) +{ + long oldcount; +#ifndef CONFIG_SMP + oldcount = sem->count; + sem->count += RWSEM_ACTIVE_READ_BIAS; +#else + long temp; + __asm__ __volatile__( + "1: ldq_l %0,%1\n" + " addq %0,%3,%2\n" + " stq_c %2,%1\n" + " beq %2,2f\n" + " mb\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) + :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory"); +#endif + if (unlikely(oldcount < 0)) + rwsem_down_read_failed(sem); +} + +/* + * trylock for reading -- returns 1 if successful, 0 if contention + */ +static inline int __down_read_trylock(struct rw_semaphore *sem) +{ + long old, new, res; + + res = sem->count; + do { + new = res + RWSEM_ACTIVE_READ_BIAS; + if (new <= 0) + break; + old = res; + res = cmpxchg(&sem->count, old, new); + } while (res != old); + return res >= 0 ? 1 : 0; +} + +static inline void __down_write(struct rw_semaphore *sem) +{ + long oldcount; +#ifndef CONFIG_SMP + oldcount = sem->count; + sem->count += RWSEM_ACTIVE_WRITE_BIAS; +#else + long temp; + __asm__ __volatile__( + "1: ldq_l %0,%1\n" + " addq %0,%3,%2\n" + " stq_c %2,%1\n" + " beq %2,2f\n" + " mb\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) + :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory"); +#endif + if (unlikely(oldcount)) + rwsem_down_write_failed(sem); +} + +/* + * trylock for writing -- returns 1 if successful, 0 if contention + */ +static inline int __down_write_trylock(struct rw_semaphore *sem) +{ + long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, + RWSEM_ACTIVE_WRITE_BIAS); + if (ret == RWSEM_UNLOCKED_VALUE) + return 1; + return 0; +} + +static inline void __up_read(struct rw_semaphore *sem) +{ + long oldcount; +#ifndef CONFIG_SMP + oldcount = sem->count; + sem->count -= RWSEM_ACTIVE_READ_BIAS; +#else + long temp; + __asm__ __volatile__( + " mb\n" + "1: ldq_l %0,%1\n" + " subq %0,%3,%2\n" + " stq_c %2,%1\n" + " beq %2,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) + :"Ir" (RWSEM_ACTIVE_READ_BIAS), "m" (sem->count) : "memory"); +#endif + if (unlikely(oldcount < 0)) + if ((int)oldcount - RWSEM_ACTIVE_READ_BIAS == 0) + rwsem_wake(sem); +} + +static inline void __up_write(struct rw_semaphore *sem) +{ + long count; +#ifndef CONFIG_SMP + sem->count -= RWSEM_ACTIVE_WRITE_BIAS; + count = sem->count; +#else + long temp; + __asm__ __volatile__( + " mb\n" + "1: ldq_l %0,%1\n" + " subq %0,%3,%2\n" + " stq_c %2,%1\n" + " beq %2,2f\n" + " subq %0,%3,%0\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (count), "=m" (sem->count), "=&r" (temp) + :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory"); +#endif + if (unlikely(count)) + if ((int)count == 0) + rwsem_wake(sem); +} + +/* + * downgrade write lock to read lock + */ +static inline void __downgrade_write(struct rw_semaphore *sem) +{ + long oldcount; +#ifndef CONFIG_SMP + oldcount = sem->count; + sem->count -= RWSEM_WAITING_BIAS; +#else + long temp; + __asm__ __volatile__( + "1: ldq_l %0,%1\n" + " addq %0,%3,%2\n" + " stq_c %2,%1\n" + " beq %2,2f\n" + " mb\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) + :"Ir" (-RWSEM_WAITING_BIAS), "m" (sem->count) : "memory"); +#endif + if (unlikely(oldcount < 0)) + rwsem_downgrade_wake(sem); +} + +static inline void rwsem_atomic_add(long val, struct rw_semaphore *sem) +{ +#ifndef CONFIG_SMP + sem->count += val; +#else + long temp; + __asm__ __volatile__( + "1: ldq_l %0,%1\n" + " addq %0,%2,%0\n" + " stq_c %0,%1\n" + " beq %0,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (temp), "=m" (sem->count) + :"Ir" (val), "m" (sem->count)); +#endif +} + +static inline long rwsem_atomic_update(long val, struct rw_semaphore *sem) +{ +#ifndef CONFIG_SMP + sem->count += val; + return sem->count; +#else + long ret, temp; + __asm__ __volatile__( + "1: ldq_l %0,%1\n" + " addq %0,%3,%2\n" + " addq %0,%3,%0\n" + " stq_c %2,%1\n" + " beq %2,2f\n" + ".subsection 2\n" + "2: br 1b\n" + ".previous" + :"=&r" (ret), "=m" (sem->count), "=&r" (temp) + :"Ir" (val), "m" (sem->count)); + + return ret; +#endif +} + +static inline int rwsem_is_locked(struct rw_semaphore *sem) +{ + return (sem->count != 0); +} + +#endif /* __KERNEL__ */ +#endif /* _ALPHA_RWSEM_H */ |