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@amd.com>
Acked-by: Mark Borden <mark.borden@amd.com>
Acked-by: Michael Hohmuth <michael.hohmuth@amd.com>
diff -r 1e74a821dd00 arch/x86/kernel/process_32.c
--- a/arch/x86/kernel/process_32.c Tue Aug 12 12:04:12 2008 -0500
+++ b/arch/x86/kernel/process_32.c Wed Aug 13 07:03:35 2008 -0500
@@ -95,7 +95,6 @@ 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;
@@ -104,6 +103,7 @@ static inline void play_dead(void)
* With physical CPU hotplug, we should halt the cpu
*/
local_irq_disable();
+ wbinvd();
while (1)
halt();
}
diff -r 1e74a821dd00 arch/x86/kernel/process_64.c
--- a/arch/x86/kernel/process_64.c Tue Aug 12 12:04:12 2008 -0500
+++ b/arch/x86/kernel/process_64.c Wed Aug 13 07:03:54 2008 -0500
@@ -93,12 +93,12 @@ 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;
local_irq_disable();
+ wbinvd();
while (1)
halt();
}
--
