s390: Use generic idle loop

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Link: http://lkml.kernel.org/r/20130321215235.090816526@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 11 insertions, 30 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index eb8fb629f00b..749513d73e47 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -97,6 +97,7 @@ config S390
         select CLONE_BACKWARDS2
         select GENERIC_CLOCKEVENTS
         select GENERIC_CPU_DEVICES if !SMP
+        select GENERIC_IDLE_LOOP
         select GENERIC_KERNEL_THREAD
         select GENERIC_SMP_IDLE_THREAD
         select GENERIC_TIME_VSYSCALL_OLD
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 536d64579d9a..2bc3eddae34a 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -61,18 +61,8 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
         return sf->gprs[8];
 }
 
-/*
- * The idle loop on a S390...
- */
-static void default_idle(void)
+void arch_cpu_idle(void)
 {
-        if (cpu_is_offline(smp_processor_id()))
-                cpu_die();
-        local_irq_disable();
-        if (need_resched()) {
-                local_irq_enable();
-                return;
-        }
         local_mcck_disable();
         if (test_thread_flag(TIF_MCCK_PENDING)) {
                 local_mcck_enable();
@@ -83,19 +73,15 @@ static void default_idle(void)
         vtime_stop_cpu();
 }
 
-void cpu_idle(void)
+void arch_cpu_idle_exit(void)
 {
-        for (;;) {
-                tick_nohz_idle_enter();
-                rcu_idle_enter();
-                while (!need_resched() && !test_thread_flag(TIF_MCCK_PENDING))
-                        default_idle();
-                rcu_idle_exit();
-                tick_nohz_idle_exit();
-                if (test_thread_flag(TIF_MCCK_PENDING))
-                        s390_handle_mcck();
-                schedule_preempt_disabled();
-        }
+        if (test_thread_flag(TIF_MCCK_PENDING))
+                s390_handle_mcck();
+}
+
+void arch_cpu_idle_dead(void)
+{
+        cpu_die();
 }
 
 extern void __kprobes kernel_thread_starter(void);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 549c9d173c0f..6ff5845679e6 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -711,8 +711,7 @@ static void __cpuinit smp_start_secondary(void *cpuvoid)
         set_cpu_online(smp_processor_id(), true);
         inc_irq_stat(CPU_RST);
         local_irq_enable();
-        /* cpu_idle will call schedule for us */
-        cpu_idle();
+        cpu_startup_entry(CPUHP_ONLINE);
 }
 
 /* Upping and downing of CPUs */
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index a0042acbd989..3fb09359eda6 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -158,8 +158,6 @@ void __kprobes vtime_stop_cpu(void)
         unsigned long psw_mask;
 
         trace_hardirqs_on();
-        /* Don't trace preempt off for idle. */
-        stop_critical_timings();
 
         /* Wait for external, I/O or machine check interrupt. */
         psw_mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_DAT |
@@ -169,9 +167,6 @@ void __kprobes vtime_stop_cpu(void)
         /* Call the assembler magic in entry.S */
         psw_idle(idle, psw_mask);
 
-        /* Reenable preemption tracer. */
-        start_critical_timings();
-
         /* Account time spent with enabled wait psw loaded as idle time. */
         idle->sequence++;
         smp_wmb();