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authorKyle McMartin <kyle@parisc-linux.org>2007-05-29 02:51:13 -0700
committerDavid S. Miller <davem@davemloft.net>2007-05-29 02:51:13 -0700
commit6197fe4d720ea3e2ee94cdc7ef32d6c0151199de (patch)
treec521b677a8ca7ab24f12c0e8275a3cbdd00131c0 /arch/sparc/lib
parent679292993c77c06f7ade4e317c13256b92c2651b (diff)
[SPARC]: Emulate cmpxchg like parisc
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/lib')
-rw-r--r--arch/sparc/lib/atomic32.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c
index 559335f4917..617d29832e1 100644
--- a/arch/sparc/lib/atomic32.c
+++ b/arch/sparc/lib/atomic32.c
@@ -2,6 +2,7 @@
* atomic32.c: 32-bit atomic_t implementation
*
* Copyright (C) 2004 Keith M Wesolowski
+ * Copyright (C) 2007 Kyle McMartin
*
* Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf
*/
@@ -117,3 +118,17 @@ unsigned long ___change_bit(unsigned long *addr, unsigned long mask)
return old & mask;
}
EXPORT_SYMBOL(___change_bit);
+
+unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new)
+{
+ unsigned long flags;
+ u32 prev;
+
+ spin_lock_irqsave(ATOMIC_HASH(addr), flags);
+ if ((prev = *ptr) == old)
+ *ptr = new;
+ spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
+
+ return (unsigned long)prev;
+}
+EXPORT_SYMBOL(__cmpxchg_u32);