x86: add periodic corruption check

Perodically check for corruption in low phusical memory.  Don't bother
checking at fault time, since it won't show anything useful.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index ee89ebc..c239b37 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -623,6 +623,7 @@
 }
 
 static int __read_mostly bios_corruption_check = 1;
+static struct timer_list periodic_check_timer;
 
 void check_for_bios_corruption(void)
 {
@@ -650,6 +651,22 @@
 		dump_stack();
 }
 
+static void periodic_check_for_corruption(unsigned long data)
+{
+	check_for_bios_corruption();
+	mod_timer(&periodic_check_timer, jiffies + 60*HZ);
+}
+
+void start_periodic_check_for_corruption(void)
+{
+	if (!bios_corruption_check)
+		return;
+
+	init_timer(&periodic_check_timer);
+	periodic_check_timer.function = &periodic_check_for_corruption;
+	periodic_check_for_corruption(0);
+}
+
 static int set_bios_corruption_check(char *arg)
 {
 	char *end;