[patch 28/28] Add cmpxchg_local to xtensa

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

Use the architecture specific __cmpxchg_u32 for 32 bits cmpxchg)_local. Else,
use the new generic cmpxchg_local (disables interrupt).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: clameter@sgi.com
chris@zankel.net
---
 include/asm-xtensa/system.h |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Index: linux-2.6-lttng/include/asm-xtensa/system.h
===================================================================
--- linux-2.6-lttng.orig/include/asm-xtensa/system.h	2007-10-31 17:32:43.000000000 -0400
+++ linux-2.6-lttng/include/asm-xtensa/system.h	2007-10-31 18:33:29.000000000 -0400
@@ -156,8 +156,30 @@ __cmpxchg(volatile void *ptr, unsigned l
 	   			        (unsigned long)_n_, sizeof (*(ptr))); \
 	})
 
+#include <asm-generic/cmpxchg-local.h>
 
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+				      unsigned long old,
+				      unsigned long new, int size)
+{
+	switch (size) {
+	case 4:
+		return __cmpxchg_u32(ptr, old, new);
+	default:
+		return __cmpxchg_local_generic(ptr, old, new, size);
+	}
 
+	return old;
+}
+
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+#define cmpxchg_local(ptr, o, n)				  	       \
+	((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
+			(unsigned long)(n), sizeof(*(ptr))))
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 
 /*
  * xchg_u32

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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