From 1996bda2a42480c275656233e631ee0966574be4 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 May 2010 14:05:13 +0200 Subject: arch: Implement local64_t On 64bit, local_t is of size long, and thus we make local64_t an alias. On 32bit, we fall back to atomic64_t. (architecture can provide optimized 32-bit version) (This new facility is to be used by perf events optimizations.) Signed-off-by: Peter Zijlstra Cc: linux-arch@vger.kernel.org Cc: Andrew Morton Cc: Linus Torvalds LKML-Reference: Signed-off-by: Ingo Molnar --- include/asm-generic/local64.h | 96 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 include/asm-generic/local64.h (limited to 'include/asm-generic') diff --git a/include/asm-generic/local64.h b/include/asm-generic/local64.h new file mode 100644 index 000000000000..02ac760c1a8b --- /dev/null +++ b/include/asm-generic/local64.h @@ -0,0 +1,96 @@ +#ifndef _ASM_GENERIC_LOCAL64_H +#define _ASM_GENERIC_LOCAL64_H + +#include +#include + +/* + * 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 + +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 + +/* 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 */ -- cgit v1.2.2