Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=85fdbe1b4b33b797321bfadf706b355e7cca6165
Commit:     85fdbe1b4b33b797321bfadf706b355e7cca6165
Parent:     df80c8c5679c4e6c72e694525d76a9f26d5f33dc
Author:     Gunnar Larisch <[EMAIL PROTECTED]>
AuthorDate: Thu Feb 7 00:16:22 2008 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Feb 7 08:42:32 2008 -0800

    Add cmpxchg_local to ppc
    
    Add a local processor version of cmpxchg for ppc.
    
    Implements __cmpxchg_u32_local and uses it for 32 bits cmpxchg_local.
    It uses the non NMI safe cmpxchg_local_generic for 1, 2 and 8 bytes
    cmpxchg_local.
    
    Signed-off-by: Gunnar Larisch <[EMAIL PROTECTED]>
    Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]>
    Cc: Paul Mackerras <[EMAIL PROTECTED]>
    Cc: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
    Cc: Kumar Gala <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 include/asm-ppc/system.h |   51 ++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/include/asm-ppc/system.h b/include/asm-ppc/system.h
index 51df94c..0593cb8 100644
--- a/include/asm-ppc/system.h
+++ b/include/asm-ppc/system.h
@@ -209,12 +209,34 @@ __cmpxchg_u32(volatile unsigned int *p, unsigned int old, 
unsigned int new)
        return prev;
 }
 
+static inline unsigned long
+__cmpxchg_u32_local(volatile unsigned int *p, unsigned int old,
+       unsigned int new)
+{
+       unsigned int prev;
+
+       __asm__ __volatile__ ("\n\
+1:     lwarx   %0,0,%2 \n\
+       cmpw    0,%0,%3 \n\
+       bne     2f \n"
+       PPC405_ERR77(0,%2)
+"      stwcx.  %4,0,%2 \n\
+       bne-    1b\n"
+"2:"
+       : "=&r" (prev), "=m" (*p)
+       : "r" (p), "r" (old), "r" (new), "m" (*p)
+       : "cc", "memory");
+
+       return prev;
+}
+
 /* 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);
 
 static __inline__ unsigned long
-__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
+__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
+       unsigned int size)
 {
        switch (size) {
        case 4:
@@ -228,7 +250,7 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned 
long new, int size)
        return old;
 }
 
-#define cmpxchg(ptr,o,n)                                                \
+#define cmpxchg(ptr, o, n)                                              \
   ({                                                                    \
      __typeof__(*(ptr)) _o_ = (o);                                      \
      __typeof__(*(ptr)) _n_ = (n);                                      \
@@ -236,6 +258,31 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned 
long new, int size)
                                    (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_local(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((ptr), (unsigned long)(o), \
+                       (unsigned long)(n), sizeof(*(ptr))))
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
+
 #define arch_align_stack(x) (x)
 
 #endif /* __KERNEL__ */
-
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