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>

1 files changed, 22 insertions, 2 deletions

diff --git a/drivers/edac/edac_module.c b/drivers/edac/edac_module.c
index 3cd3a236821c..89c96ecbf04e 100644
--- a/drivers/edac/edac_module.c
+++ b/drivers/edac/edac_module.c
@@ -1,6 +1,7 @@
 
 #include <linux/freezer.h>
 #include <linux/kthread.h>
+#include <linux/edac.h>
 
 #include "edac_mc.h"
 #include "edac_module.h"
@@ -102,6 +103,25 @@ static void do_edac_check(void)
 }
 
 /*
+ * handler for EDAC to check if NMI type handler has asserted interrupt
+ */
+static int edac_assert_error_check_and_clear(void)
+{
+        int vreg;
+
+        if(edac_op_state == EDAC_OPSTATE_POLL)
+                return 1;
+
+        vreg = atomic_read(&edac_err_assert);
+        if(vreg) {
+                atomic_set(&edac_err_assert, 0);
+                return 1;
+        }
+
+        return 0;
+}
+
+/*
  * Action thread for EDAC to perform the POLL operations
  */
 static int edac_kernel_thread(void *arg)
@@ -109,8 +129,8 @@ static int edac_kernel_thread(void *arg)
         int msec;
 
         while (!kthread_should_stop()) {
-
-                do_edac_check();
+                if(edac_assert_error_check_and_clear())
+                        do_edac_check();
 
                 /* goto sleep for the interval */
                 msec = (HZ * edac_get_poll_msec()) / 1000;