[PATCH] cpu state clean after hot remove

Clean CPU states in order to reuse smp boot code for CPU hotplug.

Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 11 deletions

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index e06f2dc7123d..5f8cfa6b7940 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -152,21 +152,19 @@ static void poll_idle (void)
 /* We don't actually take CPU down, just spin without interrupts. */
 static inline void play_dead(void)
 {
+        /* This must be done before dead CPU ack */
+        cpu_exit_clear();
+        wbinvd();
+        mb();
         /* 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();
-
+        /*
+         * With physical CPU hotplug, we should halt the cpu
+         */
         local_irq_disable();
-        __flush_tlb_all();
-        cpu_set(smp_processor_id(), cpu_online_map);
-        enable_APIC_timer();
-        local_irq_enable();
+        while (1)
+                __asm__ __volatile__("hlt":::"memory");
 }
 #else
 static inline void play_dead(void)