You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
423 lines
11 KiB
423 lines
11 KiB
#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
|
|
|
|
/*
|
|
* This barrier must provide two things:
|
|
*
|
|
* - it must guarantee a STORE before the spin_lock() is ordered against a
|
|
* LOAD after it, see the comments at its two usage sites.
|
|
*
|
|
* - it must ensure the critical section is RCsc.
|
|
*
|
|
* The latter is important for cases where we observe values written by other
|
|
* CPUs in spin-loops, without barriers, while being subject to scheduling.
|
|
*
|
|
* CPU0 CPU1 CPU2
|
|
*
|
|
* for (;;) {
|
|
* if (READ_ONCE(X))
|
|
* break;
|
|
* }
|
|
* X=1
|
|
* <sched-out>
|
|
* <sched-in>
|
|
* r = X;
|
|
*
|
|
* without transitivity it could be that CPU1 observes X!=0 breaks the loop,
|
|
* we get migrated and CPU2 sees X==0.
|
|
*
|
|
* Since most load-store architectures implement ACQUIRE with an smp_mb() after
|
|
* the LL/SC loop, they need no further barriers. Similarly all our TSO
|
|
* architectures imply an smp_mb() for each atomic instruction and equally don't
|
|
* need more.
|
|
*
|
|
* Architectures that can implement ACQUIRE better need to take care.
|
|
*/
|
|
#ifndef smp_mb__after_spinlock
|
|
#define smp_mb__after_spinlock() do { } while (0)
|
|
#endif
|
|
|
|
#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_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)
|
|
#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 */
|
|
#include <linux/rwlock.h>
|
|
|
|
/*
|
|
* 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
|
|
|
|
/*
|
|
* Map the spin_lock functions to the raw variants for PREEMPT_RT=n
|
|
*/
|
|
|
|
static __always_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 __always_inline void spin_lock(spinlock_t *lock)
|
|
{
|
|
raw_spin_lock(&lock->rlock);
|
|
}
|
|
|
|
static __always_inline void spin_lock_bh(spinlock_t *lock)
|
|
{
|
|
raw_spin_lock_bh(&lock->rlock);
|
|
}
|
|
|
|
static __always_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_nest_lock(lock, nest_lock) \
|
|
do { \
|
|
raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \
|
|
} while (0)
|
|
|
|
static __always_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 __always_inline void spin_unlock(spinlock_t *lock)
|
|
{
|
|
raw_spin_unlock(&lock->rlock);
|
|
}
|
|
|
|
static __always_inline void spin_unlock_bh(spinlock_t *lock)
|
|
{
|
|
raw_spin_unlock_bh(&lock->rlock);
|
|
}
|
|
|
|
static __always_inline void spin_unlock_irq(spinlock_t *lock)
|
|
{
|
|
raw_spin_unlock_irq(&lock->rlock);
|
|
}
|
|
|
|
static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
|
|
{
|
|
raw_spin_unlock_irqrestore(&lock->rlock, flags);
|
|
}
|
|
|
|
static __always_inline int spin_trylock_bh(spinlock_t *lock)
|
|
{
|
|
return raw_spin_trylock_bh(&lock->rlock);
|
|
}
|
|
|
|
static __always_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 __always_inline int spin_is_locked(spinlock_t *lock)
|
|
{
|
|
return raw_spin_is_locked(&lock->rlock);
|
|
}
|
|
|
|
static __always_inline int spin_is_contended(spinlock_t *lock)
|
|
{
|
|
return raw_spin_is_contended(&lock->rlock);
|
|
}
|
|
|
|
static __always_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 /* __LINUX_SPINLOCK_H */
|
|
|