[ARM PATCH] 1825/1: abort on bad code generation with div64 in some cases

Patch from Nicolas Pitre

One case was found when the kernel is compiled with -O2 (instead of the 
default -Os).  However, all gcc-3.* versions seem to have a problem with 
this.  Instead of blacklisting them all unconditionally, better just abort
when a bad case occurs especially since this bad case doesn't seem to
appear with current default compiler flags.  Depends on patch #1824.

include/asm-arm/div64.h

 #ifndef __ASM_ARM_DIV64
 #define __ASM_ARM_DIV64
 
+#include <asm/system.h>
+
 /*
  * The semantics of do_div() are:
  *
@@ -31,7 +33,11 @@
 	register unsigned long long __n   asm("r0") = n;	\
 	register unsigned long long __res asm("r2");		\
 	register unsigned int __rem       asm(__xh);		\
-	asm("bl	__do_div64"					\
+	asm(	__asmeq("%0", __xh)				\
+		__asmeq("%1", "r2")				\
+		__asmeq("%2", "r0")				\
+		__asmeq("%3", "r4")				\
+		"bl	__do_div64"				\
 		: "=r" (__rem), "=r" (__res)			\
 		: "r" (__n), "r" (__base)			\
 		: "ip", "lr", "cc");				\