arch/x86/kernel/smpboot.c: Clarify when irq processing begins.

Secondary cpus start with local interrupts disabled.
start_secondary() first initializes the new cpu, then it enables the
local interrupts. (although interrupts are enabled within smp_callin()
as well).

Right now, the local interrupts are enabled as a side effect of calling
ipi_call_lock_irq().

The attached patch clarifies when local interrupts are enabled.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 76b6f50..b700c9a 100644 (file)
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -334,14 +334,17 @@ static void __cpuinit start_secondary(void *unused)
         * does not change while we are assigning vectors to cpus.  Holding
         * this lock ensures we don't half assign or remove an irq from a cpu.
         */
-       ipi_call_lock_irq();
+       ipi_call_lock();
        lock_vector_lock();
        __setup_vector_irq(smp_processor_id());
        cpu_set(smp_processor_id(), cpu_online_map);
        unlock_vector_lock();
-       ipi_call_unlock_irq();
+       ipi_call_unlock();
        per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
 
+       /* enable local interrupts */
+       local_irq_enable();
+
        setup_secondary_clock();
 
        wmb();