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Diffstat (limited to 'kernel/arch/parisc/include/asm/atomic.h')
| -rw-r--r-- | kernel/arch/parisc/include/asm/atomic.h | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/kernel/arch/parisc/include/asm/atomic.h b/kernel/arch/parisc/include/asm/atomic.h new file mode 100644 index 000000000..226f8ca99 --- /dev/null +++ b/kernel/arch/parisc/include/asm/atomic.h @@ -0,0 +1,279 @@ +/* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> + * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org> + */ + +#ifndef _ASM_PARISC_ATOMIC_H_ +#define _ASM_PARISC_ATOMIC_H_ + +#include <linux/types.h> +#include <asm/cmpxchg.h> +#include <asm/barrier.h> + +/* + * Atomic operations that C can't guarantee us. Useful for + * resource counting etc.. + * + * And probably incredibly slow on parisc. OTOH, we don't + * have to write any serious assembly. prumpf + */ + +#ifdef CONFIG_SMP +#include <asm/spinlock.h> +#include <asm/cache.h> /* we use L1_CACHE_BYTES */ + +/* Use an array of spinlocks for our atomic_ts. + * Hash function to index into a different SPINLOCK. + * Since "a" is usually an address, use one spinlock per cacheline. + */ +# define ATOMIC_HASH_SIZE 4 +# define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ])) + +extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned; + +/* Can't use raw_spin_lock_irq because of #include problems, so + * this is the substitute */ +#define _atomic_spin_lock_irqsave(l,f) do { \ + arch_spinlock_t *s = ATOMIC_HASH(l); \ + local_irq_save(f); \ + arch_spin_lock(s); \ +} while(0) + +#define _atomic_spin_unlock_irqrestore(l,f) do { \ + arch_spinlock_t *s = ATOMIC_HASH(l); \ + arch_spin_unlock(s); \ + local_irq_restore(f); \ +} while(0) + + +#else +# define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0) +# define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0) +#endif + +/* + * Note that we need not lock read accesses - aligned word writes/reads + * are atomic, so a reader never sees inconsistent values. + */ + +static __inline__ void atomic_set(atomic_t *v, int i) +{ + unsigned long flags; + _atomic_spin_lock_irqsave(v, flags); + + v->counter = i; + + _atomic_spin_unlock_irqrestore(v, flags); +} + +static __inline__ int atomic_read(const atomic_t *v) +{ + return ACCESS_ONCE((v)->counter); +} + +/* exported interface */ +#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) +#define atomic_xchg(v, new) (xchg(&((v)->counter), new)) + +/** + * __atomic_add_unless - add unless the number is a given value + * @v: pointer of type atomic_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as it was not @u. + * Returns the old value of @v. + */ +static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) +{ + int c, old; + c = atomic_read(v); + for (;;) { + if (unlikely(c == (u))) + break; + old = atomic_cmpxchg((v), c, c + (a)); + if (likely(old == c)) + break; + c = old; + } + return c; +} + +#define ATOMIC_OP(op, c_op) \ +static __inline__ void atomic_##op(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + \ + _atomic_spin_lock_irqsave(v, flags); \ + v->counter c_op i; \ + _atomic_spin_unlock_irqrestore(v, flags); \ +} \ + +#define ATOMIC_OP_RETURN(op, c_op) \ +static __inline__ int atomic_##op##_return(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + int ret; \ + \ + _atomic_spin_lock_irqsave(v, flags); \ + ret = (v->counter c_op i); \ + _atomic_spin_unlock_irqrestore(v, flags); \ + \ + return ret; \ +} + +#define ATOMIC_OPS(op, c_op) ATOMIC_OP(op, c_op) ATOMIC_OP_RETURN(op, c_op) + +ATOMIC_OPS(add, +=) +ATOMIC_OPS(sub, -=) + +#undef ATOMIC_OPS +#undef ATOMIC_OP_RETURN +#undef ATOMIC_OP + +#define atomic_inc(v) (atomic_add( 1,(v))) +#define atomic_dec(v) (atomic_add( -1,(v))) + +#define atomic_inc_return(v) (atomic_add_return( 1,(v))) +#define atomic_dec_return(v) (atomic_add_return( -1,(v))) + +#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) + +/* + * atomic_inc_and_test - increment and test + * @v: pointer of type atomic_t + * + * Atomically increments @v by 1 + * and returns true if the result is zero, or false for all + * other cases. + */ +#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) + +#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) + +#define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0) + +#define ATOMIC_INIT(i) { (i) } + +#ifdef CONFIG_64BIT + +#define ATOMIC64_INIT(i) { (i) } + +#define ATOMIC64_OP(op, c_op) \ +static __inline__ void atomic64_##op(s64 i, atomic64_t *v) \ +{ \ + unsigned long flags; \ + \ + _atomic_spin_lock_irqsave(v, flags); \ + v->counter c_op i; \ + _atomic_spin_unlock_irqrestore(v, flags); \ +} \ + +#define ATOMIC64_OP_RETURN(op, c_op) \ +static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v) \ +{ \ + unsigned long flags; \ + s64 ret; \ + \ + _atomic_spin_lock_irqsave(v, flags); \ + ret = (v->counter c_op i); \ + _atomic_spin_unlock_irqrestore(v, flags); \ + \ + return ret; \ +} + +#define ATOMIC64_OPS(op, c_op) ATOMIC64_OP(op, c_op) ATOMIC64_OP_RETURN(op, c_op) + +ATOMIC64_OPS(add, +=) +ATOMIC64_OPS(sub, -=) + +#undef ATOMIC64_OPS +#undef ATOMIC64_OP_RETURN +#undef ATOMIC64_OP + +static __inline__ void +atomic64_set(atomic64_t *v, s64 i) +{ + unsigned long flags; + _atomic_spin_lock_irqsave(v, flags); + + v->counter = i; + + _atomic_spin_unlock_irqrestore(v, flags); +} + +static __inline__ s64 +atomic64_read(const atomic64_t *v) +{ + return ACCESS_ONCE((v)->counter); +} + +#define atomic64_inc(v) (atomic64_add( 1,(v))) +#define atomic64_dec(v) (atomic64_add( -1,(v))) + +#define atomic64_inc_return(v) (atomic64_add_return( 1,(v))) +#define atomic64_dec_return(v) (atomic64_add_return( -1,(v))) + +#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0) + +#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0) +#define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0) +#define atomic64_sub_and_test(i,v) (atomic64_sub_return((i),(v)) == 0) + +/* exported interface */ +#define atomic64_cmpxchg(v, o, n) \ + ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n))) +#define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) + +/** + * atomic64_add_unless - add unless the number is a given value + * @v: pointer of type atomic64_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as it was not @u. + * Returns the old value of @v. + */ +static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) +{ + long c, old; + c = atomic64_read(v); + for (;;) { + if (unlikely(c == (u))) + break; + old = atomic64_cmpxchg((v), c, c + (a)); + if (likely(old == c)) + break; + c = old; + } + return c != (u); +} + +#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) + +/* + * atomic64_dec_if_positive - decrement by 1 if old value positive + * @v: pointer of type atomic_t + * + * The function returns the old value of *v minus 1, even if + * the atomic variable, v, was not decremented. + */ +static inline long atomic64_dec_if_positive(atomic64_t *v) +{ + long c, old, dec; + c = atomic64_read(v); + for (;;) { + dec = c - 1; + if (unlikely(dec < 0)) + break; + old = atomic64_cmpxchg((v), c, dec); + if (likely(old == c)) + break; + c = old; + } + return dec; +} + +#endif /* !CONFIG_64BIT */ + + +#endif /* _ASM_PARISC_ATOMIC_H_ */ |