1 files changed, 25 insertions, 3 deletions

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 1c323bbfda91..cd85e34d8703 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -31,6 +31,7 @@
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/kdebug.h>
+#include <asm/s390_ext.h>
 
 #ifndef CONFIG_64BIT
 #define __FAIL_ADDR_MASK 0x7ffff000
@@ -394,6 +395,7 @@ void do_dat_exception(struct pt_regs *regs, unsigned long error_code)
 /*
  * 'pfault' pseudo page faults routines.
  */
+static ext_int_info_t ext_int_pfault;
 static int pfault_disable = 0;
 
 static int __init nopfault(char *str)
@@ -422,7 +424,7 @@ int pfault_init(void)
                   __PF_RES_FIELD };
         int rc;
 
-        if (pfault_disable)
+        if (!MACHINE_IS_VM || pfault_disable)
                 return -1;
         asm volatile(
                 "       diag    %1,%0,0x258\n"
@@ -440,7 +442,7 @@ void pfault_fini(void)
         pfault_refbk_t refbk =
         { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL };
 
-        if (pfault_disable)
+        if (!MACHINE_IS_VM || pfault_disable)
                 return;
         __ctl_clear_bit(0,9);
         asm volatile(
@@ -500,5 +502,25 @@ pfault_interrupt(__u16 error_code)
                         set_tsk_need_resched(tsk);
         }
 }
-#endif
 
+void __init pfault_irq_init(void)
+{
+        if (!MACHINE_IS_VM)
+                return;
+
+        /*
+         * Try to get pfault pseudo page faults going.
+         */
+        if (register_early_external_interrupt(0x2603, pfault_interrupt,
+                                              &ext_int_pfault) != 0)
+                panic("Couldn't request external interrupt 0x2603");
+
+        if (pfault_init() == 0)
+                return;
+
+        /* Tough luck, no pfault. */
+        pfault_disable = 1;
+        unregister_early_external_interrupt(0x2603, pfault_interrupt,
+                                            &ext_int_pfault);
+}
+#endif