[patch 18/23] Add cmpxchg_local to sh, use generic cmpxchg() instead of cmpxchg_u32

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

Use the new generic cmpxchg_local (disables interrupt). Also use the generic
cmpxchg as fallback if SMP is not set.

Since cmpxchg_u32 is _exactly_ the cmpxchg_local generic implementation, remove
it and use the generic version instead.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: clameter@sgi.com
CC: lethal@linux-sh.org
---
 include/asm-sh/system.h |   48 ++++++++++++------------------------------------
 1 file changed, 12 insertions(+), 36 deletions(-)

Index: linux-2.6-lttng/include/asm-sh/system.h
===================================================================
--- linux-2.6-lttng.orig/include/asm-sh/system.h	2007-08-07 14:31:51.000000000 -0400
+++ linux-2.6-lttng/include/asm-sh/system.h	2007-08-07 15:08:10.000000000 -0400
@@ -201,44 +201,20 @@ extern void __xchg_called_with_bad_point
 #define xchg(ptr,x)	\
 	((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
 
-static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
-	unsigned long new)
-{
-	__u32 retval;
-	unsigned long flags;
-
-	local_irq_save(flags);
-	retval = *m;
-	if (retval == old)
-		*m = new;
-	local_irq_restore(flags);       /* implies memory barrier  */
-	return retval;
-}
-
-/* This function doesn't exist, so you'll get a linker error
- * if something tries to do an invalid cmpxchg(). */
-extern void __cmpxchg_called_with_bad_pointer(void);
-
-#define __HAVE_ARCH_CMPXCHG 1
+#include <asm-generic/cmpxchg-local.h>
 
-static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
-		unsigned long new, int size)
-{
-	switch (size) {
-	case 4:
-		return __cmpxchg_u32(ptr, old, new);
-	}
-	__cmpxchg_called_with_bad_pointer();
-	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))
 
-#define cmpxchg(ptr,o,n)						 \
-  ({									 \
-     __typeof__(*(ptr)) _o_ = (o);					 \
-     __typeof__(*(ptr)) _n_ = (n);					 \
-     (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,		 \
-				    (unsigned long)_n_, sizeof(*(ptr))); \
-  })
+#ifndef CONFIG_SMP
+#include <asm-generic/cmpxchg.h>
+#endif
 
 extern void die(const char *str, struct pt_regs *regs, long err) __attribute__ ((noreturn));
 

-- 
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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