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Diffstat (limited to 'kernel/include/linux/spinlock.h')
| -rw-r--r-- | kernel/include/linux/spinlock.h | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/kernel/include/linux/spinlock.h b/kernel/include/linux/spinlock.h new file mode 100644 index 000000000..28f4366fd --- /dev/null +++ b/kernel/include/linux/spinlock.h @@ -0,0 +1,439 @@ +#ifndef __LINUX_SPINLOCK_H +#define __LINUX_SPINLOCK_H + +/* + * include/linux/spinlock.h - generic spinlock/rwlock declarations + * + * here's the role of the various spinlock/rwlock related include files: + * + * on SMP builds: + * + * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the + * initializers + * + * linux/spinlock_types.h: + * defines the generic type and initializers + * + * asm/spinlock.h: contains the arch_spin_*()/etc. lowlevel + * implementations, mostly inline assembly code + * + * (also included on UP-debug builds:) + * + * linux/spinlock_api_smp.h: + * contains the prototypes for the _spin_*() APIs. + * + * linux/spinlock.h: builds the final spin_*() APIs. + * + * on UP builds: + * + * linux/spinlock_type_up.h: + * contains the generic, simplified UP spinlock type. + * (which is an empty structure on non-debug builds) + * + * linux/spinlock_types.h: + * defines the generic type and initializers + * + * linux/spinlock_up.h: + * contains the arch_spin_*()/etc. version of UP + * builds. (which are NOPs on non-debug, non-preempt + * builds) + * + * (included on UP-non-debug builds:) + * + * linux/spinlock_api_up.h: + * builds the _spin_*() APIs. + * + * linux/spinlock.h: builds the final spin_*() APIs. + */ + +#include <linux/typecheck.h> +#include <linux/preempt.h> +#include <linux/linkage.h> +#include <linux/compiler.h> +#include <linux/irqflags.h> +#include <linux/thread_info.h> +#include <linux/kernel.h> +#include <linux/stringify.h> +#include <linux/bottom_half.h> +#include <asm/barrier.h> + + +/* + * Must define these before including other files, inline functions need them + */ +#define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME + +#define LOCK_SECTION_START(extra) \ + ".subsection 1\n\t" \ + extra \ + ".ifndef " LOCK_SECTION_NAME "\n\t" \ + LOCK_SECTION_NAME ":\n\t" \ + ".endif\n" + +#define LOCK_SECTION_END \ + ".previous\n\t" + +#define __lockfunc __attribute__((section(".spinlock.text"))) + +/* + * Pull the arch_spinlock_t and arch_rwlock_t definitions: + */ +#include <linux/spinlock_types.h> + +/* + * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them): + */ +#ifdef CONFIG_SMP +# include <asm/spinlock.h> +#else +# include <linux/spinlock_up.h> +#endif + +#ifdef CONFIG_DEBUG_SPINLOCK + extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, + struct lock_class_key *key); +# define raw_spin_lock_init(lock) \ +do { \ + static struct lock_class_key __key; \ + \ + __raw_spin_lock_init((lock), #lock, &__key); \ +} while (0) + +#else +# define raw_spin_lock_init(lock) \ + do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0) +#endif + +#define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock) + +#ifdef CONFIG_GENERIC_LOCKBREAK +#define raw_spin_is_contended(lock) ((lock)->break_lock) +#else + +#ifdef arch_spin_is_contended +#define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock) +#else +#define raw_spin_is_contended(lock) (((void)(lock), 0)) +#endif /*arch_spin_is_contended*/ +#endif + +/* + * Despite its name it doesn't necessarily has to be a full barrier. + * It should only guarantee that a STORE before the critical section + * can not be reordered with a LOAD inside this section. + * spin_lock() is the one-way barrier, this LOAD can not escape out + * of the region. So the default implementation simply ensures that + * a STORE can not move into the critical section, smp_wmb() should + * serialize it with another STORE done by spin_lock(). + */ +#ifndef smp_mb__before_spinlock +#define smp_mb__before_spinlock() smp_wmb() +#endif + +/* + * Place this after a lock-acquisition primitive to guarantee that + * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies + * if the UNLOCK and LOCK are executed by the same CPU or if the + * UNLOCK and LOCK operate on the same lock variable. + */ +#ifndef smp_mb__after_unlock_lock +#define smp_mb__after_unlock_lock() do { } while (0) +#endif + +/** + * raw_spin_unlock_wait - wait until the spinlock gets unlocked + * @lock: the spinlock in question. + */ +#define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock) + +#ifdef CONFIG_DEBUG_SPINLOCK + extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock); +#define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock) + extern int do_raw_spin_trylock(raw_spinlock_t *lock); + extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock); +#else +static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) +{ + __acquire(lock); + arch_spin_lock(&lock->raw_lock); +} + +static inline void +do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock) +{ + __acquire(lock); + arch_spin_lock_flags(&lock->raw_lock, *flags); +} + +static inline int do_raw_spin_trylock(raw_spinlock_t *lock) +{ + return arch_spin_trylock(&(lock)->raw_lock); +} + +static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) +{ + arch_spin_unlock(&lock->raw_lock); + __release(lock); +} +#endif + +/* + * Define the various spin_lock methods. Note we define these + * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The + * various methods are defined as nops in the case they are not + * required. + */ +#define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock)) + +#define raw_spin_lock(lock) _raw_spin_lock(lock) + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +# define raw_spin_lock_nested(lock, subclass) \ + _raw_spin_lock_nested(lock, subclass) +# define raw_spin_lock_bh_nested(lock, subclass) \ + _raw_spin_lock_bh_nested(lock, subclass) + +# define raw_spin_lock_nest_lock(lock, nest_lock) \ + do { \ + typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\ + _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ + } while (0) +#else +/* + * Always evaluate the 'subclass' argument to avoid that the compiler + * warns about set-but-not-used variables when building with + * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1. + */ +# define raw_spin_lock_nested(lock, subclass) \ + _raw_spin_lock(((void)(subclass), (lock))) +# define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock) +# define raw_spin_lock_bh_nested(lock, subclass) _raw_spin_lock_bh(lock) +#endif + +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) + +#define raw_spin_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + flags = _raw_spin_lock_irqsave(lock); \ + } while (0) + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +#define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ + do { \ + typecheck(unsigned long, flags); \ + flags = _raw_spin_lock_irqsave_nested(lock, subclass); \ + } while (0) +#else +#define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ + do { \ + typecheck(unsigned long, flags); \ + flags = _raw_spin_lock_irqsave(lock); \ + } while (0) +#endif + +#else + +#define raw_spin_lock_irqsave(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + _raw_spin_lock_irqsave(lock, flags); \ + } while (0) + +#define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ + raw_spin_lock_irqsave(lock, flags) + +#endif + +#define raw_spin_lock_irq(lock) _raw_spin_lock_irq(lock) +#define raw_spin_lock_bh(lock) _raw_spin_lock_bh(lock) +#define raw_spin_unlock(lock) _raw_spin_unlock(lock) +#define raw_spin_unlock_irq(lock) _raw_spin_unlock_irq(lock) + +#define raw_spin_unlock_irqrestore(lock, flags) \ + do { \ + typecheck(unsigned long, flags); \ + _raw_spin_unlock_irqrestore(lock, flags); \ + } while (0) +#define raw_spin_unlock_bh(lock) _raw_spin_unlock_bh(lock) + +#define raw_spin_trylock_bh(lock) \ + __cond_lock(lock, _raw_spin_trylock_bh(lock)) + +#define raw_spin_trylock_irq(lock) \ +({ \ + local_irq_disable(); \ + raw_spin_trylock(lock) ? \ + 1 : ({ local_irq_enable(); 0; }); \ +}) + +#define raw_spin_trylock_irqsave(lock, flags) \ +({ \ + local_irq_save(flags); \ + raw_spin_trylock(lock) ? \ + 1 : ({ local_irq_restore(flags); 0; }); \ +}) + +/** + * raw_spin_can_lock - would raw_spin_trylock() succeed? + * @lock: the spinlock in question. + */ +#define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock)) + +/* Include rwlock functions */ +#ifdef CONFIG_PREEMPT_RT_FULL +# include <linux/rwlock_rt.h> +#else +# include <linux/rwlock.h> +#endif + +/* + * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: + */ +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) +# include <linux/spinlock_api_smp.h> +#else +# include <linux/spinlock_api_up.h> +#endif + +#ifdef CONFIG_PREEMPT_RT_FULL +# include <linux/spinlock_rt.h> +#else /* PREEMPT_RT_FULL */ + +/* + * Map the spin_lock functions to the raw variants for PREEMPT_RT=n + */ + +static inline raw_spinlock_t *spinlock_check(spinlock_t *lock) +{ + return &lock->rlock; +} + +#define spin_lock_init(_lock) \ +do { \ + spinlock_check(_lock); \ + raw_spin_lock_init(&(_lock)->rlock); \ +} while (0) + +static inline void spin_lock(spinlock_t *lock) +{ + raw_spin_lock(&lock->rlock); +} + +static inline void spin_lock_bh(spinlock_t *lock) +{ + raw_spin_lock_bh(&lock->rlock); +} + +static inline int spin_trylock(spinlock_t *lock) +{ + return raw_spin_trylock(&lock->rlock); +} + +#define spin_lock_nested(lock, subclass) \ +do { \ + raw_spin_lock_nested(spinlock_check(lock), subclass); \ +} while (0) + +#define spin_lock_bh_nested(lock, subclass) \ +do { \ + raw_spin_lock_bh_nested(spinlock_check(lock), subclass);\ +} while (0) + +#define spin_lock_nest_lock(lock, nest_lock) \ +do { \ + raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \ +} while (0) + +static inline void spin_lock_irq(spinlock_t *lock) +{ + raw_spin_lock_irq(&lock->rlock); +} + +#define spin_lock_irqsave(lock, flags) \ +do { \ + raw_spin_lock_irqsave(spinlock_check(lock), flags); \ +} while (0) + +#define spin_lock_irqsave_nested(lock, flags, subclass) \ +do { \ + raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \ +} while (0) + +static inline void spin_unlock(spinlock_t *lock) +{ + raw_spin_unlock(&lock->rlock); +} + +static inline void spin_unlock_bh(spinlock_t *lock) +{ + raw_spin_unlock_bh(&lock->rlock); +} + +static inline void spin_unlock_irq(spinlock_t *lock) +{ + raw_spin_unlock_irq(&lock->rlock); +} + +static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) +{ + raw_spin_unlock_irqrestore(&lock->rlock, flags); +} + +static inline int spin_trylock_bh(spinlock_t *lock) +{ + return raw_spin_trylock_bh(&lock->rlock); +} + +static inline int spin_trylock_irq(spinlock_t *lock) +{ + return raw_spin_trylock_irq(&lock->rlock); +} + +#define spin_trylock_irqsave(lock, flags) \ +({ \ + raw_spin_trylock_irqsave(spinlock_check(lock), flags); \ +}) + +static inline void spin_unlock_wait(spinlock_t *lock) +{ + raw_spin_unlock_wait(&lock->rlock); +} + +static inline int spin_is_locked(spinlock_t *lock) +{ + return raw_spin_is_locked(&lock->rlock); +} + +static inline int spin_is_contended(spinlock_t *lock) +{ + return raw_spin_is_contended(&lock->rlock); +} + +static inline int spin_can_lock(spinlock_t *lock) +{ + return raw_spin_can_lock(&lock->rlock); +} + +#define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) + +/* + * Pull the atomic_t declaration: + * (asm-mips/atomic.h needs above definitions) + */ +#include <linux/atomic.h> +/** + * atomic_dec_and_lock - lock on reaching reference count zero + * @atomic: the atomic counter + * @lock: the spinlock in question + * + * Decrements @atomic by 1. If the result is 0, returns true and locks + * @lock. Returns false for all other cases. + */ +extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); +#define atomic_dec_and_lock(atomic, lock) \ + __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) + +#endif /* !PREEMPT_RT_FULL */ + +#endif /* __LINUX_SPINLOCK_H */ |