define and implement wrong_size_cmpxchg() for arm

arch/arm/kernel/Makefile

@@ -15,7 +15,7 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 obj-y		:= compat.o elf.o entry-armv.o entry-common.o irq.o \
 		   process.o ptrace.o return_address.o setup.o signal.o \
-		   sys_arm.o stacktrace.o time.o traps.o
+		   sys_arm.o stacktrace.o time.o traps.o cmpxchg-local.o
 
 obj-$(CONFIG_ISA_DMA_API)	+= dma.o
 obj-$(CONFIG_ARCH_ACORN)	+= ecard.o 

arch/arm/kernel/cmpxchg-local.c

+/*
+ * arch/arm/kernel/cmpxchg-local.c
+ * 
+ * Copyright (C) 2009, M2X BV, All Rights Reserved
+ * Author: Jean-Paul Saman <jean-paul.saman@m2x.nl>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <asm-generic/cmpxchg-local.h>
+
+void wrong_size_cmpxchg(volatile void *ptr)
+{
+	printk(KERN_ERR "Wrong sized cmpxchg");
+	BUG();
+}
+

include/asm-generic/cmpxchg-local.h

@@ -3,7 +3,7 @@
 
 #include <linux/types.h>
 
-extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
+extern void wrong_size_cmpxchg(volatile void *ptr);
 
 /*
  * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
@@ -12,7 +12,7 @@ extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
 static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
 		unsigned long old, unsigned long new, int size)
 {
-	unsigned long flags, prev;
+	unsigned long flags, prev = 0;
 
 	/*
 	 * Sanity checking, compile-time.