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authorManfred Spraul <manfred@colorfullife.com>2008-09-07 16:57:22 +0200
committerIngo Molnar <mingo@elte.hu>2008-09-08 19:25:24 +0200
commite545a6140b698b2494daf0b32107bdcc5e901390 (patch)
tree63f302e25ba7a0705bbf051f3817fac8f8b98aba /kernel/cpu.c
parent7686ad5606f08d9dfb33a2087a36c8366366015b (diff)
downloadlinux-2.6.34-ux500-e545a6140b698b2494daf0b32107bdcc5e901390.tar.gz
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>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index f17e9854c24..dc45f2459ef 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -453,6 +453,25 @@ out:
}
#endif /* CONFIG_PM_SLEEP_SMP */
+/**
+ * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
+ * @cpu: cpu that just started
+ *
+ * This function calls the cpu_chain notifiers with CPU_STARTING.
+ * It must be called by the arch code on the new cpu, before the new cpu
+ * enables interrupts and before the "boot" cpu returns from __cpu_up().
+ */
+void notify_cpu_starting(unsigned int cpu)
+{
+ unsigned long val = CPU_STARTING;
+
+#ifdef CONFIG_PM_SLEEP_SMP
+ if (cpu_isset(cpu, frozen_cpus))
+ val = CPU_STARTING_FROZEN;
+#endif /* CONFIG_PM_SLEEP_SMP */
+ raw_notifier_call_chain(&cpu_chain, val, (void *)(long)cpu);
+}
+
#endif /* CONFIG_SMP */
/*