drivers/edac: add new nmi rescan

Provides a way for NMI reported errors on x86 to notify the EDAC
subsystem pending ECC errors by writing to a software state variable.

Here's the reworked patch. I added an EDAC stub to the kernel so we can
have variables that are in the kernel even if EDAC is a module. I also
implemented the idea of using the chip driver to select error detection
mode via module parameter and eliminate the kernel compile option.
Please review/test. Thx!

Also, I only made changes to some of the chipset drivers since I am
unfamiliar with the other ones. We can add similar changes as we go.

Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 109ebbc..3e7753c 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -41,6 +41,10 @@
 #include <linux/mca.h>
 #endif
 
+#if defined(CONFIG_EDAC)
+#include <linux/edac.h>
+#endif
+
 #include <asm/processor.h>
 #include <asm/system.h>
 #include <asm/io.h>
@@ -638,6 +642,14 @@
 	printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
 		"CPU %d.\n", reason, smp_processor_id());
 	printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n");
+
+#if defined(CONFIG_EDAC)
+	if(edac_handler_set()) {
+		edac_atomic_assert_error();
+		return;
+	}
+#endif
+
 	if (panic_on_unrecovered_nmi)
                 panic("NMI: Not continuing");