Make TIF_MCE_NOTIFY optional

So that we don't have to implement it on 32bit.

I would actually like to remove it on 64bit too.


Signed-off-by: Andi Kleen <ak@suse.de>

---
 arch/x86/Kconfig                    |    5 +++++
 arch/x86/kernel/cpu/mcheck/mce_64.c |   16 ++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

Index: linux/arch/x86/kernel/cpu/mcheck/mce_64.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/mcheck/mce_64.c
+++ linux/arch/x86/kernel/cpu/mcheck/mce_64.c
@@ -148,6 +148,13 @@ static void mce_panic(char *msg, struct 
 	panic(msg);
 }
 
+static void mce_notify_userspace(void)
+{
+#ifdef CONFIG_MCE_NOTIFY
+	set_thread_flag(TIF_MCE_NOTIFY);
+#endif
+}
+
 static int mce_available(struct cpuinfo_x86 *c)
 {
 	return cpu_has(c, X86_FEATURE_MCE) && cpu_has(c, X86_FEATURE_MCA);
@@ -305,8 +312,7 @@ void do_machine_check(struct pt_regs * r
 		}
 	}
 
-	/* notify userspace ASAP */
-	set_thread_flag(TIF_MCE_NOTIFY);
+	mce_notify_userspace();
 
  out:
 	/* the last thing we do is clear state */
@@ -387,7 +393,9 @@ static void mcheck_timer(struct work_str
  */
 int mce_notify_user(void)
 {
+#ifdef CONFIG_MCE_NOTIFY
 	clear_thread_flag(TIF_MCE_NOTIFY);
+#endif
 	if (test_and_clear_bit(0, &notify_user)) {
 		static unsigned long last_print;
 		unsigned long now = jiffies;
@@ -407,6 +415,7 @@ int mce_notify_user(void)
 	return 0;
 }
 
+#ifdef CONFIG_MCE_NOTIFY
 /* see if the idle task needs to notify userspace */
 static int
 mce_idle_callback(struct notifier_block *nfb, unsigned long action, void *junk)
@@ -421,6 +430,7 @@ mce_idle_callback(struct notifier_block 
 static struct notifier_block mce_idle_notifier = {
 	.notifier_call = mce_idle_callback,
 };
+#endif
 
 static __init int periodic_mcheck_init(void)
 {
@@ -428,7 +438,9 @@ static __init int periodic_mcheck_init(v
 	if (next_interval)
 		schedule_delayed_work(&mcheck_work,
 				      round_jiffies_relative(next_interval));
+#ifdef CONFIG_MCE_NOTIFY
 	idle_notifier_register(&mce_idle_notifier);
+#endif
 	return 0;
 }
 __initcall(periodic_mcheck_init);
Index: linux/arch/x86/Kconfig
===================================================================
--- linux.orig/arch/x86/Kconfig
+++ linux/arch/x86/Kconfig
@@ -555,6 +555,11 @@ config X86_MCE
 	  to disable it.  MCE support simply ignores non-MCE processors like
 	  the 386 and 486, so nearly everyone can say Y here.
 
+config MCE_NOTIFY
+	bool
+	default y
+	depends on X86_64
+
 config X86_MCE_INTEL
 	def_bool y
 	prompt "Intel MCE features"