/* * Copyright (2004) Linus Torvalds * * Author: Zwane Mwaikambo <zwane@fsmlabs.com> * * Copyright (2004, 2005) Ingo Molnar * * This file contains the spinlock/rwlock implementations for the * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them) */ #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(raw_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); #if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) 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) \ { \ for (;;) { \ preempt_disable(); \ 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(); \ } \ (lock)->break_lock = 0; \ } \ \ EXPORT_SYMBOL(_##op##_lock); \ \ unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ { \ unsigned long flags; \ \ for (;;) { \ preempt_disable(); \ 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(); \ } \ (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_no_resched(); 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_no_resched(); 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_no_resched(); 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_no_resched(); 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);