diff options
Diffstat (limited to 'kernel/spinlock.c')
| -rw-r--r-- | kernel/spinlock.c | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/kernel/spinlock.c b/kernel/spinlock.c new file mode 100644 index 00000000000..e15ed17863f --- /dev/null +++ b/kernel/spinlock.c @@ -0,0 +1,371 @@ +/* + * Copyright (2004) Linus Torvalds + * + * Author: Zwane Mwaikambo <zwane@fsmlabs.com> + * + * Copyright (2004) Ingo Molnar + */ + +#include <linux/config.h> +#include <linux/linkage.h> +#include <linux/preempt.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/module.h> + +/* + * Generic declaration of the raw read_trylock() function, + * architectures are supposed to optimize this: + */ +int __lockfunc generic_raw_read_trylock(rwlock_t *lock) +{ + _raw_read_lock(lock); + return 1; +} +EXPORT_SYMBOL(generic_raw_read_trylock); + +int __lockfunc _spin_trylock(spinlock_t *lock) +{ + preempt_disable(); + if (_raw_spin_trylock(lock)) + return 1; + + preempt_enable(); + return 0; +} +EXPORT_SYMBOL(_spin_trylock); + +int __lockfunc _read_trylock(rwlock_t *lock) +{ + preempt_disable(); + if (_raw_read_trylock(lock)) + return 1; + + preempt_enable(); + return 0; +} +EXPORT_SYMBOL(_read_trylock); + +int __lockfunc _write_trylock(rwlock_t *lock) +{ + preempt_disable(); + if (_raw_write_trylock(lock)) + return 1; + + preempt_enable(); + return 0; +} +EXPORT_SYMBOL(_write_trylock); + +#ifndef CONFIG_PREEMPT + +void __lockfunc _read_lock(rwlock_t *lock) +{ + preempt_disable(); + _raw_read_lock(lock); +} +EXPORT_SYMBOL(_read_lock); + +unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) +{ + unsigned long flags; + + local_irq_save(flags); + preempt_disable(); + _raw_spin_lock_flags(lock, flags); + return flags; +} +EXPORT_SYMBOL(_spin_lock_irqsave); + +void __lockfunc _spin_lock_irq(spinlock_t *lock) +{ + local_irq_disable(); + preempt_disable(); + _raw_spin_lock(lock); +} +EXPORT_SYMBOL(_spin_lock_irq); + +void __lockfunc _spin_lock_bh(spinlock_t *lock) +{ + local_bh_disable(); + preempt_disable(); + _raw_spin_lock(lock); +} +EXPORT_SYMBOL(_spin_lock_bh); + +unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) +{ + unsigned long flags; + + local_irq_save(flags); + preempt_disable(); + _raw_read_lock(lock); + return flags; +} +EXPORT_SYMBOL(_read_lock_irqsave); + +void __lockfunc _read_lock_irq(rwlock_t *lock) +{ + local_irq_disable(); + preempt_disable(); + _raw_read_lock(lock); +} +EXPORT_SYMBOL(_read_lock_irq); + +void __lockfunc _read_lock_bh(rwlock_t *lock) +{ + local_bh_disable(); + preempt_disable(); + _raw_read_lock(lock); +} +EXPORT_SYMBOL(_read_lock_bh); + +unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) +{ + unsigned long flags; + + local_irq_save(flags); + preempt_disable(); + _raw_write_lock(lock); + return flags; +} +EXPORT_SYMBOL(_write_lock_irqsave); + +void __lockfunc _write_lock_irq(rwlock_t *lock) +{ + local_irq_disable(); + preempt_disable(); + _raw_write_lock(lock); +} +EXPORT_SYMBOL(_write_lock_irq); + +void __lockfunc _write_lock_bh(rwlock_t *lock) +{ + local_bh_disable(); + preempt_disable(); + _raw_write_lock(lock); +} +EXPORT_SYMBOL(_write_lock_bh); + +void __lockfunc _spin_lock(spinlock_t *lock) +{ + preempt_disable(); + _raw_spin_lock(lock); +} + +EXPORT_SYMBOL(_spin_lock); + +void __lockfunc _write_lock(rwlock_t *lock) +{ + preempt_disable(); + _raw_write_lock(lock); +} + +EXPORT_SYMBOL(_write_lock); + +#else /* CONFIG_PREEMPT: */ + +/* + * This could be a long-held lock. We both prepare to spin for a long + * time (making _this_ CPU preemptable if possible), and we also signal + * towards that other CPU that it should break the lock ASAP. + * + * (We do this in a function because inlining it would be excessive.) + */ + +#define BUILD_LOCK_OPS(op, locktype) \ +void __lockfunc _##op##_lock(locktype##_t *lock) \ +{ \ + preempt_disable(); \ + for (;;) { \ + if (likely(_raw_##op##_trylock(lock))) \ + break; \ + preempt_enable(); \ + if (!(lock)->break_lock) \ + (lock)->break_lock = 1; \ + while (!op##_can_lock(lock) && (lock)->break_lock) \ + cpu_relax(); \ + preempt_disable(); \ + } \ + (lock)->break_lock = 0; \ +} \ + \ +EXPORT_SYMBOL(_##op##_lock); \ + \ +unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ +{ \ + unsigned long flags; \ + \ + preempt_disable(); \ + for (;;) { \ + local_irq_save(flags); \ + if (likely(_raw_##op##_trylock(lock))) \ + break; \ + local_irq_restore(flags); \ + \ + preempt_enable(); \ + if (!(lock)->break_lock) \ + (lock)->break_lock = 1; \ + while (!op##_can_lock(lock) && (lock)->break_lock) \ + cpu_relax(); \ + preempt_disable(); \ + } \ + (lock)->break_lock = 0; \ + return flags; \ +} \ + \ +EXPORT_SYMBOL(_##op##_lock_irqsave); \ + \ +void __lockfunc _##op##_lock_irq(locktype##_t *lock) \ +{ \ + _##op##_lock_irqsave(lock); \ +} \ + \ +EXPORT_SYMBOL(_##op##_lock_irq); \ + \ +void __lockfunc _##op##_lock_bh(locktype##_t *lock) \ +{ \ + unsigned long flags; \ + \ + /* */ \ + /* Careful: we must exclude softirqs too, hence the */ \ + /* irq-disabling. We use the generic preemption-aware */ \ + /* function: */ \ + /**/ \ + flags = _##op##_lock_irqsave(lock); \ + local_bh_disable(); \ + local_irq_restore(flags); \ +} \ + \ +EXPORT_SYMBOL(_##op##_lock_bh) + +/* + * Build preemption-friendly versions of the following + * lock-spinning functions: + * + * _[spin|read|write]_lock() + * _[spin|read|write]_lock_irq() + * _[spin|read|write]_lock_irqsave() + * _[spin|read|write]_lock_bh() + */ +BUILD_LOCK_OPS(spin, spinlock); +BUILD_LOCK_OPS(read, rwlock); +BUILD_LOCK_OPS(write, rwlock); + +#endif /* CONFIG_PREEMPT */ + +void __lockfunc _spin_unlock(spinlock_t *lock) +{ + _raw_spin_unlock(lock); + preempt_enable(); +} +EXPORT_SYMBOL(_spin_unlock); + +void __lockfunc _write_unlock(rwlock_t *lock) +{ + _raw_write_unlock(lock); + preempt_enable(); +} +EXPORT_SYMBOL(_write_unlock); + +void __lockfunc _read_unlock(rwlock_t *lock) +{ + _raw_read_unlock(lock); + preempt_enable(); +} +EXPORT_SYMBOL(_read_unlock); + +void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) +{ + _raw_spin_unlock(lock); + local_irq_restore(flags); + preempt_enable(); +} +EXPORT_SYMBOL(_spin_unlock_irqrestore); + +void __lockfunc _spin_unlock_irq(spinlock_t *lock) +{ + _raw_spin_unlock(lock); + local_irq_enable(); + preempt_enable(); +} +EXPORT_SYMBOL(_spin_unlock_irq); + +void __lockfunc _spin_unlock_bh(spinlock_t *lock) +{ + _raw_spin_unlock(lock); + preempt_enable(); + local_bh_enable(); +} +EXPORT_SYMBOL(_spin_unlock_bh); + +void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) +{ + _raw_read_unlock(lock); + local_irq_restore(flags); + preempt_enable(); +} +EXPORT_SYMBOL(_read_unlock_irqrestore); + +void __lockfunc _read_unlock_irq(rwlock_t *lock) +{ + _raw_read_unlock(lock); + local_irq_enable(); + preempt_enable(); +} +EXPORT_SYMBOL(_read_unlock_irq); + +void __lockfunc _read_unlock_bh(rwlock_t *lock) +{ + _raw_read_unlock(lock); + preempt_enable(); + local_bh_enable(); +} +EXPORT_SYMBOL(_read_unlock_bh); + +void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) +{ + _raw_write_unlock(lock); + local_irq_restore(flags); + preempt_enable(); +} +EXPORT_SYMBOL(_write_unlock_irqrestore); + +void __lockfunc _write_unlock_irq(rwlock_t *lock) +{ + _raw_write_unlock(lock); + local_irq_enable(); + preempt_enable(); +} +EXPORT_SYMBOL(_write_unlock_irq); + +void __lockfunc _write_unlock_bh(rwlock_t *lock) +{ + _raw_write_unlock(lock); + preempt_enable(); + local_bh_enable(); +} +EXPORT_SYMBOL(_write_unlock_bh); + +int __lockfunc _spin_trylock_bh(spinlock_t *lock) +{ + local_bh_disable(); + preempt_disable(); + if (_raw_spin_trylock(lock)) + return 1; + + preempt_enable(); + local_bh_enable(); + return 0; +} +EXPORT_SYMBOL(_spin_trylock_bh); + +int in_lock_functions(unsigned long addr) +{ + /* Linker adds these: start and end of __lockfunc functions */ + extern char __lock_text_start[], __lock_text_end[]; + + return addr >= (unsigned long)__lock_text_start + && addr < (unsigned long)__lock_text_end; +} +EXPORT_SYMBOL(in_lock_functions); |