X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=include%2Fasm-sparc%2Fatomic.h;h=3328950dbfe6de8df7f8ae1dbad525f9636f38bb;hb=b5faa4b89e4d83203b1f44f143a351b518f7cda2;hp=731fa56e0c374c8413c41c8460f16f4844d7046b;hpb=55b4d6a52195a8f277ffddf755ddaff359878f41;p=linux-2.6

diff --git a/include/asm-sparc/atomic.h b/include/asm-sparc/atomic.h
index 731fa56e0c..3328950dbf 100644
--- a/include/asm-sparc/atomic.h
+++ b/include/asm-sparc/atomic.h
@@ -1,7 +1,8 @@
 /* atomic.h: These still suck, but the I-cache hit rate is higher.
  *
- * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
  * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
+ * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
  *
  * Additions by Keith M Wesolowski (wesolows@foobazco.org) based
  * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
@@ -10,11 +11,48 @@
 #ifndef __ARCH_SPARC_ATOMIC__
 #define __ARCH_SPARC_ATOMIC__
 
+#include <linux/types.h>
 
 typedef struct { volatile int counter; } atomic_t;
 
 #ifdef __KERNEL__
 
+/* Emulate cmpxchg() the same way we emulate atomics,
+ * by hashing the object address and indexing into an array
+ * of spinlocks to get a bit of performance...
+ *
+ * See arch/sparc/lib/atomic32.c for implementation.
+ *
+ * Cribbed from <asm-parisc/atomic.h>
+ */
+#define __HAVE_ARCH_CMPXCHG	1
+
+/* bug catcher for when unsupported size is used - won't link */
+extern void __cmpxchg_called_with_bad_pointer(void);
+/* we only need to support cmpxchg of a u32 on sparc */
+extern unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
+
+/* don't worry...optimizer will get rid of most of this */
+static inline unsigned long
+__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
+{
+	switch(size) {
+	case 4:
+		return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
+	default:
+		__cmpxchg_called_with_bad_pointer();
+		break;
+	}
+	return old;
+}
+
+#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)));		\
+})
+
 #define ATOMIC_INIT(i)  { (i) }
 
 extern int __atomic_add_return(int, atomic_t *);