invalidate caches before going into suspend

[Mark Langsdorf]

When a CPU core is shut down, all of its caches need to be flushed
to prevent stale data from causing errors if the core is resumed.
Current Linux suspend code performs an assignment after the flush,
which can add dirty data back to the cache.  On some AMD platforms,
additional speculative reads have caused crashes on resume because
of this dirty data.

Relocate the cache flush to be the very last thing done before 
halting.


Signed-off-by: Mark Langsdorf <mark.langsdorf@xxxxxxx>
Acked-by: Mark Borden <mark.borden@xxxxxxx>
Acked-by: Michael Hohmuth <michael.hohmuth@xxxxxxx>

diff -r f3f819497a68 arch/x86/kernel/process_64.c
--- a/arch/x86/kernel/process_64.c	Thu Aug 07 04:24:53 2008 -0500
+++ b/arch/x86/kernel/process_64.c	Tue Aug 12 07:11:36 2008 -0500
@@ -93,11 +93,11 @@ static inline void play_dead(void)
 static inline void play_dead(void)
 {
 	idle_task_exit();
-	wbinvd();
 	mb();
 	/* Ack it */
 	__get_cpu_var(cpu_state) = CPU_DEAD;
 
+	wbinvd();
 	local_irq_disable();
 	while (1)
 		halt();


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