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#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H
#ifndef __SMP__
/*
* Your basic spinlocks, allowing only a single CPU anywhere
*/
typedef struct { } spinlock_t;
#define SPIN_LOCK_UNLOCKED { }
#define spin_lock_init(lock) do { } while(0)
#define spin_lock(lock) do { } while(0)
#define spin_trylock(lock) do { } while(0)
#define spin_unlock_wait(lock) do { } while(0)
#define spin_unlock(lock) do { } while(0)
#define spin_lock_irq(lock) cli()
#define spin_unlock_irq(lock) sti()
#define spin_lock_irqsave(lock, flags) \
do { save_flags(flags); cli(); } while (0)
#define spin_unlock_irqrestore(lock, flags) \
restore_flags(flags)
/*
* Read-write spinlocks, allowing multiple readers
* but only one writer.
*
* NOTE! it is quite common to have readers in interrupts
* but no interrupt writers. For those circumstances we
* can "mix" irq-safe locks - any writer needs to get a
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
typedef struct { } rwlock_t;
#define RW_LOCK_UNLOCKED { }
#define read_lock(lock) do { } while(0)
#define read_unlock(lock) do { } while(0)
#define write_lock(lock) do { } while(0)
#define write_unlock(lock) do { } while(0)
#define read_lock_irq(lock) cli()
#define read_unlock_irq(lock) sti()
#define write_lock_irq(lock) cli()
#define write_unlock_irq(lock) sti()
#define read_lock_irqsave(lock, flags) \
do { save_flags(flags); cli(); } while (0)
#define read_unlock_irqrestore(lock, flags) \
restore_flags(flags)
#define write_lock_irqsave(lock, flags) \
do { save_flags(flags); cli(); } while (0)
#define write_unlock_irqrestore(lock, flags) \
restore_flags(flags)
#else
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
* on the local processor, one does not.
*
* We make no fairness assumptions. They have a cost.
*/
typedef struct {
volatile unsigned int lock;
} spinlock_t;
#define SPIN_LOCK_UNLOCKED { 0 }
#define spin_lock_init(x) do { (x)->lock = 0; } while(0)
#define spin_unlock_wait(x) do { barrier(); } while(((volatile spinlock_t *)(x))->lock)
typedef struct { unsigned long a[100]; } __dummy_lock_t;
#define __dummy_lock(lock) (*(__dummy_lock_t *)(lock))
#define spin_lock(lock) \
__asm__ __volatile__( \
"\n1:\t" \
"lock ; btsl $0,%0\n\t" \
"jc 2f\n" \
".section .text.lock,\"ax\"\n" \
"2:\t" \
"testb $1,%0\n\t" \
"jne 2b\n\t" \
"jmp 1b\n" \
".previous" \
:"=m" (__dummy_lock(lock)))
#define spin_unlock(lock) \
__asm__ __volatile__( \
"lock ; btrl $0,%0" \
:"=m" (__dummy_lock(lock)))
#define spin_trylock(lock) (!test_and_set_bit(0,(lock)))
#define spin_lock_irq(lock) \
do { __cli(); spin_lock(lock); } while (0)
#define spin_unlock_irq(lock) \
do { spin_unlock(lock); __sti(); } while (0)
#define spin_lock_irqsave(lock, flags) \
do { __save_flags(flags); __cli(); spin_lock(lock); } while (0)
#define spin_unlock_irqrestore(lock, flags) \
do { spin_unlock(lock); __restore_flags(flags); } while (0)
/*
* Read-write spinlocks, allowing multiple readers
* but only one writer.
*
* NOTE! it is quite common to have readers in interrupts
* but no interrupt writers. For those circumstances we
* can "mix" irq-safe locks - any writer needs to get a
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
typedef struct {
volatile unsigned int lock;
unsigned long previous;
} rwlock_t;
#define RW_LOCK_UNLOCKED { 0, 0 }
/*
* On x86, we implement read-write locks as a 32-bit counter
* with the high bit (sign) being the "write" bit.
*
* The inline assembly is non-obvious. Think about it.
*/
#define read_lock(rw) \
asm volatile("\n1:\t" \
"lock ; incl %0\n\t" \
"js 2f\n" \
".section .text.lock,\"ax\"\n" \
"2:\tlock ; decl %0\n" \
"3:\tcmpl $0,%0\n\t" \
"js 3b\n\t" \
"jmp 1b\n" \
".previous" \
:"=m" (__dummy_lock(&(rw)->lock)))
#define read_unlock(rw) \
asm volatile("lock ; decl %0" \
:"=m" (__dummy_lock(&(rw)->lock)))
#define write_lock(rw) \
asm volatile("\n1:\t" \
"lock ; btsl $31,%0\n\t" \
"jc 4f\n" \
"2:\ttestl $0x7fffffff,%0\n\t" \
"jne 3f\n" \
".section .text.lock,\"ax\"\n" \
"3:\tlock ; btrl $31,%0\n" \
"4:\tcmp $0,%0\n\t" \
"jne 4b\n\t" \
"jmp 1b\n" \
".previous" \
:"=m" (__dummy_lock(&(rw)->lock)))
#define write_unlock(rw) \
asm volatile("lock ; btrl $31,%0":"=m" (__dummy_lock(&(rw)->lock)))
#define read_lock_irq(lock) do { __cli(); read_lock(lock); } while (0)
#define read_unlock_irq(lock) do { read_unlock(lock); __sti(); } while (0)
#define write_lock_irq(lock) do { __cli(); write_lock(lock); } while (0)
#define write_unlock_irq(lock) do { write_unlock(lock); __sti(); } while (0)
#define read_lock_irqsave(lock, flags) \
do { __save_flags(flags); __cli(); read_lock(lock); } while (0)
#define read_unlock_irqrestore(lock, flags) \
do { read_unlock(lock); __restore_flags(flags); } while (0)
#define write_lock_irqsave(lock, flags) \
do { __save_flags(flags); __cli(); write_lock(lock); } while (0)
#define write_unlock_irqrestore(lock, flags) \
do { write_unlock(lock); __restore_flags(flags); } while (0)
#endif /* SMP */
#endif /* __ASM_SPINLOCK_H */
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