1 files changed, 28 insertions, 5 deletions

diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c
index 3bf466603512..5ae14803091f 100644
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -362,12 +362,19 @@ s390_revalidate_registers(struct mci *mci)
         return kill_task;
 }
 
+#define MAX_IPD_COUNT   29
+#define MAX_IPD_TIME    (5 * 60 * 100 * 1000) /* 5 minutes */
+
 /*
  * machine check handler.
  */
 void
 s390_do_machine_check(struct pt_regs *regs)
 {
+        static DEFINE_SPINLOCK(ipd_lock);
+        static unsigned long long last_ipd;
+        static int ipd_count;
+        unsigned long long tmp;
         struct mci *mci;
         struct mcck_struct *mcck;
         int umode;
@@ -404,11 +411,27 @@ s390_do_machine_check(struct pt_regs *regs)
                                 s390_handle_damage("processing backup machine "
                                                    "check with damage.");
                         }
-                        if (!umode)
-                                s390_handle_damage("processing backup machine "
-                                                   "check in kernel mode.");
-                        mcck->kill_task = 1;
-                        mcck->mcck_code = *(unsigned long long *) mci;
+
+                        /*
+                         * Nullifying exigent condition, therefore we might
+                         * retry this instruction.
+                         */
+
+                        spin_lock(&ipd_lock);
+
+                        tmp = get_clock();
+
+                        if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
+                                ipd_count++;
+                        else
+                                ipd_count = 1;
+
+                        last_ipd = tmp;
+
+                        if (ipd_count == MAX_IPD_COUNT)
+                                s390_handle_damage("too many ipd retries.");
+
+                        spin_unlock(&ipd_lock);
                 }
                 else {
                         /* Processing damage -> stopping machine */