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

From: Mathieu Desnoyers
Date: Mon Aug 20 2007 - 16:22:53 EST


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@xxxxxxxxxx>
CC: clameter@xxxxxxx
CC: lethal@xxxxxxxxxxxx
---
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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