kernel/cpu.c: create a CPU_STARTING cpu_chain notifier
Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.
The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.
Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 00b9b4d..9e8b1f9 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -585,6 +585,8 @@
/* Enable pfault pseudo page faults on this cpu. */
pfault_init();
+ /* call cpu notifiers */
+ notify_cpu_starting(smp_processor_id());
/* Mark this cpu as online */
spin_lock(&call_lock);
cpu_set(smp_processor_id(), cpu_online_map);
