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Diffstat (limited to 'arch/i386/kernel/process.c')
-rw-r--r--arch/i386/kernel/process.c39
1 files changed, 38 insertions, 1 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index aea2ce1145df..c1b11e8df60b 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -13,6 +13,7 @@
#include <stdarg.h>
+#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/fs.h>
@@ -55,6 +56,9 @@
#include <linux/irq.h>
#include <linux/err.h>
+#include <asm/tlbflush.h>
+#include <asm/cpu.h>
+
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
static int hlt_counter;
@@ -143,14 +147,44 @@ static void poll_idle (void)
}
}
+#ifdef CONFIG_HOTPLUG_CPU
+#include <asm/nmi.h>
+/* We don't actually take CPU down, just spin without interrupts. */
+static inline void play_dead(void)
+{
+ /* Ack it */
+ __get_cpu_var(cpu_state) = CPU_DEAD;
+
+ /* We shouldn't have to disable interrupts while dead, but
+ * some interrupts just don't seem to go away, and this makes
+ * it "work" for testing purposes. */
+ /* Death loop */
+ while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
+ cpu_relax();
+
+ local_irq_disable();
+ __flush_tlb_all();
+ cpu_set(smp_processor_id(), cpu_online_map);
+ enable_APIC_timer();
+ local_irq_enable();
+}
+#else
+static inline void play_dead(void)
+{
+ BUG();
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
/*
* The idle thread. There's no useful work to be
* done, so just try to conserve power and have a
* low exit latency (ie sit in a loop waiting for
* somebody to say that they'd like to reschedule)
*/
-void cpu_idle (void)
+void cpu_idle(void)
{
+ int cpu = raw_smp_processor_id();
+
/* endless idle loop with no priority at all */
while (1) {
while (!need_resched()) {
@@ -165,6 +199,9 @@ void cpu_idle (void)
if (!idle)
idle = default_idle;
+ if (cpu_is_offline(cpu))
+ play_dead();
+
__get_cpu_var(irq_stat).idle_timestamp = jiffies;
idle();
}