/* * 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) * * Note that some architectures have special knowledge about the * stack frames of these functions in their profile_pc. If you * change anything significant here that could change the stack * frame contact the architecture maintainers. */ #include <linux/linkage.h> #include <linux/preempt.h> #include <linux/spinlock.h> #include <linux/interrupt.h> #include <linux/debug_locks.h> #include <linux/export.h> /* * If lockdep is enabled then we use the non-preemption spin-ops * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are * not re-enabled during lock-acquire (which the preempt-spin-ops do): */ #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) /* * The __lock_function inlines are taken from * include/linux/spinlock_api_smp.h */ #else #define raw_read_can_lock(l) read_can_lock(l) #define raw_write_can_lock(l) write_can_lock(l) /* * Some architectures can relax in favour of the CPU owning the lock. */ #ifndef arch_read_relax # define arch_read_relax(l) cpu_relax() #endif #ifndef arch_write_relax # define arch_write_relax(l) cpu_relax() #endif #ifndef arch_spin_relax # define arch_spin_relax(l) cpu_relax() #endif /* * We build the __lock_function inlines here. They are too large for * inlining all over the place, but here is only one user per function * which embedds them into the calling _lock_function below. * * 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. */ #define BUILD_LOCK_OPS(op, locktype) \ void __lockfunc __raw_##op##_lock(locktype##_t *lock) \ { \ for (;;) { \ preempt_disable(); \ if (likely(do_raw_##op##_trylock(lock))) \ break; \ preempt_enable(); \ \ if (!(lock)->break_lock) \ (lock)->break_lock = 1; \ while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\ arch_##op##_relax(&lock->raw_lock); \ } \ (lock)->break_lock = 0; \ } \ \ unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \ { \ unsigned long flags; \ \ for (;;) { \ preempt_disable(); \ local_irq_save(flags); \ if (likely(do_raw_##op##_trylock(lock))) \ break; \ local_irq_restore(flags); \ preempt_enable(); \ \ if (!(lock)->break_lock) \ (lock)->break_lock = 1; \ while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\ arch_##op##_relax(&lock->raw_lock); \ } \ (lock)->break_lock = 0; \ return flags; \ } \ \ void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \ { \ _raw_##op##_lock_irqsave(lock); \ } \ \ void __lockfunc __raw_##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 = _raw_##op##_lock_irqsave(lock); \ local_bh_disable(); \ local_irq_restore(flags); \ } \ /* * 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, raw_spinlock); BUILD_LOCK_OPS(read, rwlock); BUILD_LOCK_OPS(write, rwlock); #endif #ifndef CONFIG_INLINE_SPIN_TRYLOCK int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock) { return __raw_spin_trylock(lock); } EXPORT_SYMBOL(_raw_spin_trylock); #endif #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock) { return __raw_spin_trylock_bh(lock); } EXPORT_SYMBOL(_raw_spin_trylock_bh); #endif #ifndef CONFIG_INLINE_SPIN_LOCK void __lockfunc _raw_spin_lock(raw_spinlock_t *lock) { __raw_spin_lock(lock); } EXPORT_SYMBOL(_raw_spin_lock); #endif #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock) { return __raw_spin_lock_irqsave(lock); } EXPORT_SYMBOL(_raw_spin_lock_irqsave); #endif #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock) { __raw_spin_lock_irq(lock); } EXPORT_SYMBOL(_raw_spin_lock_irq); #endif #ifndef CONFIG_INLINE_SPIN_LOCK_BH void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock) { __raw_spin_lock_bh(lock); } EXPORT_SYMBOL(_raw_spin_lock_bh); #endif #ifdef CONFIG_UNINLINE_SPIN_UNLOCK void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock) { __raw_spin_unlock(lock); } EXPORT_SYMBOL(_raw_spin_unlock); #endif #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags) { __raw_spin_unlock_irqrestore(lock, flags); } EXPORT_SYMBOL(_raw_spin_unlock_irqrestore); #endif #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock) { __raw_spin_unlock_irq(lock); } EXPORT_SYMBOL(_raw_spin_unlock_irq); #endif #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock) { __raw_spin_unlock_bh(lock); } EXPORT_SYMBOL(_raw_spin_unlock_bh); #endif #ifndef CONFIG_INLINE_READ_TRYLOCK int __lockfunc _raw_read_trylock(rwlock_t *lock) { return __raw_read_trylock(lock); } EXPORT_SYMBOL(_raw_read_trylock); #endif #ifndef CONFIG_INLINE_READ_LOCK void __lockfunc _raw_read_lock(rwlock_t *lock) { __raw_read_lock(lock); } EXPORT_SYMBOL(_raw_read_lock); #endif #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock) { return __raw_read_lock_irqsave(lock); } EXPORT_SYMBOL(_raw_read_lock_irqsave); #endif #ifndef CONFIG_INLINE_READ_LOCK_IRQ void __lockfunc _raw_read_lock_irq(rwlock_t *lock) { __raw_read_lock_irq(lock); } EXPORT_SYMBOL(_raw_read_lock_irq); #endif #ifndef CONFIG_INLINE_READ_LOCK_BH void __lockfunc _raw_read_lock_bh(rwlock_t *lock) { __raw_read_lock_bh(lock); } EXPORT_SYMBOL(_raw_read_lock_bh); #endif #ifndef CONFIG_INLINE_READ_UNLOCK void __lockfunc _raw_read_unlock(rwlock_t *lock) { __raw_read_unlock(lock); } EXPORT_SYMBOL(_raw_read_unlock); #endif #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) { __raw_read_unlock_irqrestore(lock, flags); } EXPORT_SYMBOL(_raw_read_unlock_irqrestore); #endif #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ void __lockfunc _raw_read_unlock_irq(rwlock_t *lock) { __raw_read_unlock_irq(lock); } EXPORT_SYMBOL(_raw_read_unlock_irq); #endif #ifndef CONFIG_INLINE_READ_UNLOCK_BH void __lockfunc _raw_read_unlock_bh(rwlock_t *lock) { __raw_read_unlock_bh(lock); } EXPORT_SYMBOL(_raw_read_unlock_bh); #endif #ifndef CONFIG_INLINE_WRITE_TRYLOCK int __lockfunc _raw_write_trylock(rwlock_t *lock) { return __raw_write_trylock(lock); } EXPORT_SYMBOL(_raw_write_trylock); #endif #ifndef CONFIG_INLINE_WRITE_LOCK void __lockfunc _raw_write_lock(rwlock_t *lock) { __raw_write_lock(lock); } EXPORT_SYMBOL(_raw_write_lock); #endif #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock) { return __raw_write_lock_irqsave(lock); } EXPORT_SYMBOL(_raw_write_lock_irqsave); #endif #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ void __lockfunc _raw_write_lock_irq(rwlock_t *lock) { __raw_write_lock_irq(lock); } EXPORT_SYMBOL(_raw_write_lock_irq); #endif #ifndef CONFIG_INLINE_WRITE_LOCK_BH void __lockfunc _raw_write_lock_bh(rwlock_t *lock) { __raw_write_lock_bh(lock); } EXPORT_SYMBOL(_raw_write_lock_bh); #endif #ifndef CONFIG_INLINE_WRITE_UNLOCK void __lockfunc _raw_write_unlock(rwlock_t *lock) { __raw_write_unlock(lock); } EXPORT_SYMBOL(_raw_write_unlock); #endif #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) { __raw_write_unlock_irqrestore(lock, flags); } EXPORT_SYMBOL(_raw_write_unlock_irqrestore); #endif #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ void __lockfunc _raw_write_unlock_irq(rwlock_t *lock) { __raw_write_unlock_irq(lock); } EXPORT_SYMBOL(_raw_write_unlock_irq); #endif #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH void __lockfunc _raw_write_unlock_bh(rwlock_t *lock) { __raw_write_unlock_bh(lock); } EXPORT_SYMBOL(_raw_write_unlock_bh); #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass) { preempt_disable(); spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock); } EXPORT_SYMBOL(_raw_spin_lock_nested); unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock, int subclass) { unsigned long flags; local_irq_save(flags); preempt_disable(); spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock, do_raw_spin_lock_flags, &flags); return flags; } EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested); void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock, struct lockdep_map *nest_lock) { preempt_disable(); spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock); } EXPORT_SYMBOL(_raw_spin_lock_nest_lock); #endif notrace 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);