s390/smp: Handle restart interrupt on ipl cpu

The current smp code allows to trigger a restart interrupt on CPUs
offline in linux. To allow using the percpu infrastructure instead
of the pcpu_devices array, switch to the ipl cpu which is always
online before calling do_restart().
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/smp.h

@@ -24,7 +24,6 @@ extern int __cpu_up(unsigned int cpu, struct task_struct *tidle);
 extern void arch_send_call_function_single_ipi(int cpu);
 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
 
-extern void smp_call_online_cpu(void (*func)(void *), void *);
 extern void smp_call_ipl_cpu(void (*func)(void *), void *);
 extern void smp_emergency_stop(void);
 

arch/s390/kernel/ipl.c

@@ -2112,7 +2112,7 @@ void do_restart(void *arg)
 	tracing_off();
 	debug_locks_off();
 	lgr_info_log();
-	smp_call_online_cpu(__do_restart, arg);
+	smp_call_ipl_cpu(__do_restart, arg);
 }
 
 /* on halt */

arch/s390/kernel/smp.c

@@ -382,21 +382,6 @@ static int pcpu_set_smt(unsigned int mtid)
 	return cc;
 }
 
-/*
- * Call function on an online CPU.
- */
-void smp_call_online_cpu(void (*func)(void *), void *data)
-{
-	struct pcpu *pcpu;
-
-	/* Use the current cpu if it is online. */
-	pcpu = pcpu_find_address(cpu_online_mask, stap());
-	if (!pcpu)
-		/* Use the first online cpu. */
-		pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
-	pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
-}
-
 /*
  * Call function on the ipl CPU.
  */