Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  kdump: Allow shrinking of kdump region to be overridden
  powerpc/pmac/smp: Remove no-longer needed preempt workaround
  powerpc/smp: Increase vdso_data->processorCount, not just decrease it
  powerpc/smp: Create idle threads on demand and properly reset them
  powerpc/smp: Don't expose per-cpu "cpu_state" array
  powerpc/pmac/smp: Fix CPU hotplug crashes on some machines
  powerpc/smp: Add a smp_ops->bringup_up() done callback
  powerpc/pmac: Rename cpu_state in therm_pm72 to avoid collision
  powerpc/pmac/smp: Properly NAP offlined CPU on G5
  powerpc/pmac/smp: Remove HMT changes for PowerMac offline code
  powerpc/pmac/smp: Consolidate 32-bit and 64-bit PowerMac cpu_die in one file
  powerpc/pmac/smp: Fixup smp_core99_cpu_disable() and use it on 64-bit
  powerpc/pmac/smp: Rename fixup_irqs() to migrate_irqs() and use it on ppc32
  powerpc/pmac/smp: Fix 32-bit PowerMac cpu_die
  powerpc/smp: Remove unused smp_ops->cpu_enable()
  powerpc/smp: Remove unused generic_cpu_enable()
  powerpc/smp: Fix generic_mach_cpu_die()
  powerpc/smp: soft-replugged CPUs must go back to start_secondary
  powerpc: Make decrementer interrupt robust against offlined CPUs

1 files changed, 11 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index aa9269600ca2..375480c56eb9 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -577,14 +577,21 @@ void timer_interrupt(struct pt_regs * regs)
         struct clock_event_device *evt = &decrementer->event;
         u64 now;
 
+        /* Ensure a positive value is written to the decrementer, or else
+         * some CPUs will continue to take decrementer exceptions.
+         */
+        set_dec(DECREMENTER_MAX);
+
+        /* Some implementations of hotplug will get timer interrupts while
+         * offline, just ignore these
+         */
+        if (!cpu_online(smp_processor_id()))
+                return;
+
         trace_timer_interrupt_entry(regs);
 
         __get_cpu_var(irq_stat).timer_irqs++;
 
-        /* Ensure a positive value is written to the decrementer, or else
-         * some CPUs will continuue to take decrementer exceptions */
-        set_dec(DECREMENTER_MAX);
-
 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
         if (atomic_read(&ppc_n_lost_interrupts) != 0)
                 do_IRQ(regs);