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Diffstat (limited to 'include/asm-generic/local64.h')
| -rw-r--r-- | include/asm-generic/local64.h | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/include/asm-generic/local64.h b/include/asm-generic/local64.h new file mode 100644 index 000000000..765be0b7d --- /dev/null +++ b/include/asm-generic/local64.h @@ -0,0 +1,97 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_LOCAL64_H +#define _ASM_GENERIC_LOCAL64_H + +#include <linux/percpu.h> +#include <asm/types.h> + +/* + * A signed long type for operations which are atomic for a single CPU. + * Usually used in combination with per-cpu variables. + * + * This is the default implementation, which uses atomic64_t. Which is + * rather pointless. The whole point behind local64_t is that some processors + * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs + * running on this CPU. local64_t allows exploitation of such capabilities. + */ + +/* Implement in terms of atomics. */ + +#if BITS_PER_LONG == 64 + +#include <asm/local.h> + +typedef struct { + local_t a; +} local64_t; + +#define LOCAL64_INIT(i) { LOCAL_INIT(i) } + +#define local64_read(l) local_read(&(l)->a) +#define local64_set(l,i) local_set((&(l)->a),(i)) +#define local64_inc(l) local_inc(&(l)->a) +#define local64_dec(l) local_dec(&(l)->a) +#define local64_add(i,l) local_add((i),(&(l)->a)) +#define local64_sub(i,l) local_sub((i),(&(l)->a)) + +#define local64_sub_and_test(i, l) local_sub_and_test((i), (&(l)->a)) +#define local64_dec_and_test(l) local_dec_and_test(&(l)->a) +#define local64_inc_and_test(l) local_inc_and_test(&(l)->a) +#define local64_add_negative(i, l) local_add_negative((i), (&(l)->a)) +#define local64_add_return(i, l) local_add_return((i), (&(l)->a)) +#define local64_sub_return(i, l) local_sub_return((i), (&(l)->a)) +#define local64_inc_return(l) local_inc_return(&(l)->a) + +#define local64_cmpxchg(l, o, n) local_cmpxchg((&(l)->a), (o), (n)) +#define local64_xchg(l, n) local_xchg((&(l)->a), (n)) +#define local64_add_unless(l, _a, u) local_add_unless((&(l)->a), (_a), (u)) +#define local64_inc_not_zero(l) local_inc_not_zero(&(l)->a) + +/* Non-atomic variants, ie. preemption disabled and won't be touched + * in interrupt, etc. Some archs can optimize this case well. */ +#define __local64_inc(l) local64_set((l), local64_read(l) + 1) +#define __local64_dec(l) local64_set((l), local64_read(l) - 1) +#define __local64_add(i,l) local64_set((l), local64_read(l) + (i)) +#define __local64_sub(i,l) local64_set((l), local64_read(l) - (i)) + +#else /* BITS_PER_LONG != 64 */ + +#include <linux/atomic.h> + +/* Don't use typedef: don't want them to be mixed with atomic_t's. */ +typedef struct { + atomic64_t a; +} local64_t; + +#define LOCAL64_INIT(i) { ATOMIC_LONG_INIT(i) } + +#define local64_read(l) atomic64_read(&(l)->a) +#define local64_set(l,i) atomic64_set((&(l)->a),(i)) +#define local64_inc(l) atomic64_inc(&(l)->a) +#define local64_dec(l) atomic64_dec(&(l)->a) +#define local64_add(i,l) atomic64_add((i),(&(l)->a)) +#define local64_sub(i,l) atomic64_sub((i),(&(l)->a)) + +#define local64_sub_and_test(i, l) atomic64_sub_and_test((i), (&(l)->a)) +#define local64_dec_and_test(l) atomic64_dec_and_test(&(l)->a) +#define local64_inc_and_test(l) atomic64_inc_and_test(&(l)->a) +#define local64_add_negative(i, l) atomic64_add_negative((i), (&(l)->a)) +#define local64_add_return(i, l) atomic64_add_return((i), (&(l)->a)) +#define local64_sub_return(i, l) atomic64_sub_return((i), (&(l)->a)) +#define local64_inc_return(l) atomic64_inc_return(&(l)->a) + +#define local64_cmpxchg(l, o, n) atomic64_cmpxchg((&(l)->a), (o), (n)) +#define local64_xchg(l, n) atomic64_xchg((&(l)->a), (n)) +#define local64_add_unless(l, _a, u) atomic64_add_unless((&(l)->a), (_a), (u)) +#define local64_inc_not_zero(l) atomic64_inc_not_zero(&(l)->a) + +/* Non-atomic variants, ie. preemption disabled and won't be touched + * in interrupt, etc. Some archs can optimize this case well. */ +#define __local64_inc(l) local64_set((l), local64_read(l) + 1) +#define __local64_dec(l) local64_set((l), local64_read(l) - 1) +#define __local64_add(i,l) local64_set((l), local64_read(l) + (i)) +#define __local64_sub(i,l) local64_set((l), local64_read(l) - (i)) + +#endif /* BITS_PER_LONG != 64 */ + +#endif /* _ASM_GENERIC_LOCAL64_H */ |