x86: separate generic cpu disabling code from APIC writes in cpu_disable

It allows paravirt implementations of cpu_disable to share the
cpu_disable_common code, without having to take on board APIC
writes, which may not be appropriate.

Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 24 insertions, 17 deletions

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 28b4287296aa..66b04e598817 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1346,25 +1346,9 @@ static void __ref remove_cpu_from_maps(int cpu)
         numa_remove_cpu(cpu);
 }
 
-int native_cpu_disable(void)
+void cpu_disable_common(void)
 {
         int cpu = smp_processor_id();
-
-        /*
-         * Perhaps use cpufreq to drop frequency, but that could go
-         * into generic code.
-         *
-         * We won't take down the boot processor on i386 due to some
-         * interrupts only being able to be serviced by the BSP.
-         * Especially so if we're not using an IOAPIC   -zwane
-         */
-        if (cpu == 0)
-                return -EBUSY;
-
-        if (nmi_watchdog == NMI_LOCAL_APIC)
-                stop_apic_nmi_watchdog(NULL);
-        clear_local_APIC();
-
         /*
          * HACK:
          * Allow any queued timer interrupts to get serviced
@@ -1382,6 +1366,28 @@ int native_cpu_disable(void)
         remove_cpu_from_maps(cpu);
         unlock_vector_lock();
         fixup_irqs(cpu_online_map);
+}
+
+int native_cpu_disable(void)
+{
+        int cpu = smp_processor_id();
+
+        /*
+         * Perhaps use cpufreq to drop frequency, but that could go
+         * into generic code.
+         *
+         * We won't take down the boot processor on i386 due to some
+         * interrupts only being able to be serviced by the BSP.
+         * Especially so if we're not using an IOAPIC   -zwane
+         */
+        if (cpu == 0)
+                return -EBUSY;
+
+        if (nmi_watchdog == NMI_LOCAL_APIC)
+                stop_apic_nmi_watchdog(NULL);
+        clear_local_APIC();
+
+        cpu_disable_common();
         return 0;
 }
 
diff --git a/include/asm-x86/smp.h b/include/asm-x86/smp.h
index 17305e72f348..8bdaa4a25f05 100644
--- a/include/asm-x86/smp.h
+++ b/include/asm-x86/smp.h
@@ -125,6 +125,7 @@ static inline void arch_send_call_function_ipi(cpumask_t mask)
         smp_ops.send_call_func_ipi(mask);
 }
 
+void cpu_disable_common(void);
 void native_smp_prepare_boot_cpu(void);
 void native_smp_prepare_cpus(unsigned int max_cpus);
 void native_smp_cpus_done(unsigned int max_cpus);