ia64: Remove ia64_spinlock_contention().

arch/ia64/kernel/head.S

@@ -733,73 +733,3 @@ SET_REG(b4);
 SET_REG(b5);
 
 #endif /* CONFIG_IA64_BRL_EMU */
-
-#ifdef CONFIG_SMP
-
-	/*
-	 * This routine handles spinlock contention.  It uses a simple exponential backoff
-	 * algorithm to reduce unnecessary bus traffic.  The initial delay is selected from
-	 * the low-order bits of the cycle counter (a cheap "randomizer").  I'm sure this
-	 * could use additional tuning, especially on systems with a large number of CPUs.
-	 * Also, I think the maximum delay should be made a function of the number of CPUs in
-	 * the system. --davidm 00/08/05
-	 *
-	 * WARNING: This is not a normal procedure.  It gets called from C code without
-	 * the compiler knowing about it.  Thus, we must not use any scratch registers
-	 * beyond those that were declared "clobbered" at the call-site (see spin_lock()
-	 * macro).  We may not even use the stacked registers, because that could overwrite
-	 * output registers.  Similarly, we can't use the scratch stack area as it may be
-	 * in use, too.
-	 *
-	 * Inputs:
-	 *	ar.ccv = 0 (and available for use)
-	 *	r28 = available for use
-	 *	r29 = available for use
-	 *	r30 = non-zero (and available for use)
-	 *	r31 = address of lock we're trying to acquire
-	 *	p15 = available for use
-	 */
-
-#	define delay	r28
-#	define timeout	r29
-#	define tmp	r30
-
-GLOBAL_ENTRY(ia64_spinlock_contention)
-	mov tmp=ar.itc
-	;;
-	and delay=0x3f,tmp
-	;;
-
-.retry:	add timeout=tmp,delay
-	shl delay=delay,1
-	;;
-	dep delay=delay,r0,0,13	// limit delay to 8192 cycles
-	;;
-	// delay a little...
-.wait:	sub tmp=tmp,timeout
-	or delay=0xf,delay	// make sure delay is non-zero (otherwise we get stuck with 0)
-	;;
-	cmp.lt p15,p0=tmp,r0
-	mov tmp=ar.itc
-(p15)	br.cond.sptk .wait
-	;;
-	ld4 tmp=[r31]
-	;;
-	cmp.ne p15,p0=tmp,r0
-	mov tmp=ar.itc
-(p15)	br.cond.sptk .retry	// lock is still busy
-	;;
-	// try acquiring lock (we know ar.ccv is still zero!):
-	mov tmp=1
-	;;
-	cmpxchg4.acq tmp=[r31],tmp,ar.ccv
-	;;
-	cmp.eq p15,p0=tmp,r0
-
-	mov tmp=ar.itc
-(p15)	br.ret.sptk.many b7	// got lock -> return
-	br .retry		// still no luck, retry
-
-END(ia64_spinlock_contention)
-
-#endif