diff options
Diffstat (limited to 'sys/arch/mvme88k/include/mplock.h')
| -rw-r--r-- | sys/arch/mvme88k/include/mplock.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/sys/arch/mvme88k/include/mplock.h b/sys/arch/mvme88k/include/mplock.h new file mode 100644 index 00000000000..8f87c895aae --- /dev/null +++ b/sys/arch/mvme88k/include/mplock.h @@ -0,0 +1,191 @@ +/* $OpenBSD: mplock.h,v 1.1 2007/11/26 17:15:29 art Exp $ */ + +/* + * Copyright (c) 2004 Niklas Hallqvist. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _MACHINE_MPLOCK_H_ +#define _MACHINE_MPLOCK_H_ + +/* + * Really simple spinlock implementation with recursive capabilities. + * Correctness is paramount, no fancyness allowed. + */ + +struct __mp_lock { + __cpu_simple_lock_t mpl_lock; + cpuid_t mpl_cpu; + int mpl_count; +}; + +static __inline void +__mp_lock_init(struct __mp_lock *lock) +{ + __cpu_simple_lock_init(&lock->mpl_lock); + lock->mpl_cpu = LK_NOCPU; + lock->mpl_count = 0; +} + +#if defined(MP_LOCKDEBUG) +#ifndef DDB +#error "MP_LOCKDEBUG requires DDB" +#endif + +extern void Debugger(void); +extern int db_printf(const char *, ...) + __attribute__((__format__(__kprintf__,1,2))); + +/* CPU-dependent timing, needs this to be settable from ddb. */ +extern int __mp_lock_spinout; +#endif + +static __inline void +__mp_lock(struct __mp_lock *lock) +{ + int s = spllock(); + + if (lock->mpl_cpu != cpu_number()) { +#ifndef MP_LOCKDEBUG + __cpu_simple_lock(&lock->mpl_lock); +#else + { + int got_it; + do { + int ticks = __mp_lock_spinout; + + do { + got_it = __cpu_simple_lock_try( + &lock->mpl_lock); + } while (!got_it && ticks-- > 0); + if (!got_it) { + db_printf( + "__mp_lock(0x%x): lock spun out", + lock); + Debugger(); + } + } while (!got_it); + } +#endif + lock->mpl_cpu = cpu_number(); + } + lock->mpl_count++; + splx(s); +} + +/* + * Try to acquire the lock, if another cpu has it, fill it in the + * call-by-reference cpu parameter. Return true if acquired. + */ +static __inline int +__mp_lock_try(struct __mp_lock *lock, cpuid_t *cpu) +{ + int s = spllock(); + + if (lock->mpl_cpu != cpu_number()) { + if (!__cpu_simple_lock_try(&lock->mpl_lock)) { + *cpu = lock->mpl_cpu; + splx(s); + return 0; + } + lock->mpl_cpu = cpu_number(); + } + lock->mpl_count++; + splx(s); + return 1; +} + +static __inline void +__mp_unlock(struct __mp_lock *lock) +{ + int s = spllock(); + +#ifdef MP_LOCKDEBUG + if (lock->mpl_count == 0 || lock->mpl_cpu == LK_NOCPU) { + db_printf("__mp_unlock(0x%x): releasing not locked lock\n", + lock); + Debugger(); + } +#endif + + if (--lock->mpl_count == 0) { + lock->mpl_cpu = LK_NOCPU; + __cpu_simple_unlock(&lock->mpl_lock); + } + splx(s); +} + +static __inline int +__mp_release_all(struct __mp_lock *lock) { + int s = spllock(); + int rv = lock->mpl_count; + +#ifdef MP_LOCKDEBUG + if (lock->mpl_count == 0 || lock->mpl_cpu == LK_NOCPU) { + db_printf( + "__mp_release_all(0x%x): releasing not locked lock\n", + lock); + Debugger(); + } +#endif + + lock->mpl_cpu = LK_NOCPU; + lock->mpl_count = 0; + __cpu_simple_unlock(&lock->mpl_lock); + splx(s); + return (rv); +} + +static __inline int +__mp_release_all_but_one(struct __mp_lock *lock) { + int s = spllock(); + int rv = lock->mpl_count - 1; + +#ifdef MP_LOCKDEBUG + if (lock->mpl_count == 0 || lock->mpl_cpu == LK_NOCPU) { + db_printf( + "__mp_release_all_but_one(0x%x): releasing not locked lock\n", + lock); + Debugger(); + } +#endif + + lock->mpl_count = 1; + splx(s); + return (rv); +} + +static __inline void +__mp_acquire_count(struct __mp_lock *lock, int count) { + int s = spllock(); + + while (count--) + __mp_lock(lock); + splx(s); +} + +static __inline int +__mp_lock_held(struct __mp_lock *lock) { + return lock->mpl_count && lock->mpl_cpu == cpu_number(); +} + +#endif /* !_MACHINE_MPLOCK_H */ |