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-rw-r--r--arch/powerpc/kernel/smp.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 2b952b5386fd..e5b133ebd8a5 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -427,6 +427,45 @@ int generic_check_cpu_restart(unsigned int cpu)
{
return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
}
+
+static atomic_t secondary_inhibit_count;
+
+/*
+ * Don't allow secondary CPU threads to come online
+ */
+void inhibit_secondary_onlining(void)
+{
+ /*
+ * This makes secondary_inhibit_count stable during cpu
+ * online/offline operations.
+ */
+ get_online_cpus();
+
+ atomic_inc(&secondary_inhibit_count);
+ put_online_cpus();
+}
+EXPORT_SYMBOL_GPL(inhibit_secondary_onlining);
+
+/*
+ * Allow secondary CPU threads to come online again
+ */
+void uninhibit_secondary_onlining(void)
+{
+ get_online_cpus();
+ atomic_dec(&secondary_inhibit_count);
+ put_online_cpus();
+}
+EXPORT_SYMBOL_GPL(uninhibit_secondary_onlining);
+
+static int secondaries_inhibited(void)
+{
+ return atomic_read(&secondary_inhibit_count);
+}
+
+#else /* HOTPLUG_CPU */
+
+#define secondaries_inhibited() 0
+
#endif
static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
@@ -445,6 +484,13 @@ int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
int rc, c;
+ /*
+ * Don't allow secondary threads to come online if inhibited
+ */
+ if (threads_per_core > 1 && secondaries_inhibited() &&
+ cpu % threads_per_core != 0)
+ return -EBUSY;
+
if (smp_ops == NULL ||
(smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
return -EINVAL;
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