aboutsummaryrefslogtreecommitdiffstats
path: root/include/asm-generic
diff options
context:
space:
mode:
authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-05-21 14:05:13 +0200
committerIngo Molnar <mingo@elte.hu>2010-06-09 11:12:36 +0200
commit1996bda2a42480c275656233e631ee0966574be4 (patch)
treec4c61b6bde252d3d6f1dc0b62d48cf3a3e486ec1 /include/asm-generic
parentd57e34fdd60be7ffd0b1d86bfa1a553df86b7172 (diff)
downloadmrst-s0i3-test-1996bda2a42480c275656233e631ee0966574be4.tar.gz
mrst-s0i3-test-1996bda2a42480c275656233e631ee0966574be4.tar.xz
mrst-s0i3-test-1996bda2a42480c275656233e631ee0966574be4.zip
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 <a.p.zijlstra@chello.nl> Cc: linux-arch@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/local64.h96
1 files changed, 96 insertions, 0 deletions
diff --git a/include/asm-generic/local64.h b/include/asm-generic/local64.h
new file mode 100644
index 00000000000..02ac760c1a8
--- /dev/null
+++ b/include/asm-generic/local64.h
@@ -0,0 +1,96 @@
+#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 <asm/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 */