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>

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 28b4287..66b04e5 100644 (file)
--- 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 17305e7..8bdaa4a 100644 (file)
--- 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);