3 files changed, 32 insertions, 11 deletions

diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index ac151399ef34..1995c1712fc8 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -95,7 +95,6 @@ EXPORT_SYMBOL_GPL(s390_handle_mcck);
 static int notrace s390_revalidate_registers(struct mci *mci)
 {
         int kill_task;
-        u64 tmpclock;
         u64 zero;
         void *fpt_save_area, *fpt_creg_save_area;
 
@@ -214,11 +213,10 @@ static int notrace s390_revalidate_registers(struct mci *mci)
                         : "0", "cc");
 #endif
         /* Revalidate clock comparator register */
-        asm volatile(
-                "       stck    0(%1)\n"
-                "       sckc    0(%1)"
-                : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
-
+        if (S390_lowcore.clock_comparator == -1)
+                set_clock_comparator(S390_lowcore.mcck_clock);
+        else
+                set_clock_comparator(S390_lowcore.clock_comparator);
         /* Check if old PSW is valid */
         if (!mci->wp)
                 /*
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 3479f1b0d4e0..c1e326cedea5 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -19,6 +19,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/rcupdate.h>
 #include <linux/posix-timers.h>
+#include <linux/cpu.h>
 
 #include <asm/s390_ext.h>
 #include <asm/timer.h>
@@ -565,6 +566,23 @@ void init_cpu_vtimer(void)
         __ctl_set_bit(0,10);
 }
 
+static int __cpuinit s390_nohz_notify(struct notifier_block *self,
+                                      unsigned long action, void *hcpu)
+{
+        struct s390_idle_data *idle;
+        long cpu = (long) hcpu;
+
+        idle = &per_cpu(s390_idle, cpu);
+        switch (action) {
+        case CPU_DYING:
+        case CPU_DYING_FROZEN:
+                idle->nohz_delay = 0;
+        default:
+                break;
+        }
+        return NOTIFY_OK;
+}
+
 void __init vtime_init(void)
 {
         /* request the cpu timer external interrupt */
@@ -573,5 +591,6 @@ void __init vtime_init(void)
 
         /* Enable cpu timer interrupts on the boot cpu. */
         init_cpu_vtimer();
+        cpu_notifier(s390_nohz_notify, 0);
 }
 
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 752b362bf651..7c37ec359ec2 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -29,17 +29,21 @@ static void __udelay_disabled(unsigned long long usecs)
 {
         unsigned long mask, cr0, cr0_saved;
         u64 clock_saved;
+        u64 end;
 
+        mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
+        end = get_clock() + (usecs << 12);
         clock_saved = local_tick_disable();
-        set_clock_comparator(get_clock() + (usecs << 12));
         __ctl_store(cr0_saved, 0, 0);
         cr0 = (cr0_saved & 0xffff00e0) | 0x00000800;
         __ctl_load(cr0 , 0, 0);
-        mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
         lockdep_off();
-        trace_hardirqs_on();
-        __load_psw_mask(mask);
-        local_irq_disable();
+        do {
+                set_clock_comparator(end);
+                trace_hardirqs_on();
+                __load_psw_mask(mask);
+                local_irq_disable();
+        } while (get_clock() < end);
         lockdep_on();
         __ctl_load(cr0_saved, 0, 0);
         local_tick_enable(clock_saved);