2 files changed, 25 insertions, 33 deletions

diff --git a/arch/s390/power/swsusp.c b/arch/s390/power/swsusp.c
index e6a4fe9f5f24..bd1f5c6b0b8c 100644
--- a/arch/s390/power/swsusp.c
+++ b/arch/s390/power/swsusp.c
@@ -7,24 +7,36 @@
  *
  */
 
+#include <asm/system.h>
 
-/*
- * save CPU registers before creating a hibernation image and before
- * restoring the memory state from it
- */
 void save_processor_state(void)
 {
-        /* implentation contained in the
-         * swsusp_arch_suspend function
+        /* swsusp_arch_suspend() actually saves all cpu register contents.
+         * Machine checks must be disabled since swsusp_arch_suspend() stores
+         * register contents to their lowcore save areas. That's the same
+         * place where register contents on machine checks would be saved.
+         * To avoid register corruption disable machine checks.
+         * We must also disable machine checks in the new psw mask for
+         * program checks, since swsusp_arch_suspend() may generate program
+         * checks. Disabling machine checks for all other new psw masks is
+         * just paranoia.
          */
+        local_mcck_disable();
+        /* Disable lowcore protection */
+        __ctl_clear_bit(0,28);
+        S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
+        S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
+        S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
+        S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
 }
 
-/*
- * restore the contents of CPU registers
- */
 void restore_processor_state(void)
 {
-        /* implentation contained in the
-         * swsusp_arch_resume function
-         */
+        S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
+        S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
+        S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
+        S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
+        /* Enable lowcore protection */
+        __ctl_set_bit(0,28);
+        local_mcck_enable();
 }
diff --git a/arch/s390/power/swsusp_asm64.S b/arch/s390/power/swsusp_asm64.S
index e27bd3164897..b26df5c5933e 100644
--- a/arch/s390/power/swsusp_asm64.S
+++ b/arch/s390/power/swsusp_asm64.S
@@ -32,11 +32,6 @@ swsusp_arch_suspend:
         /* Deactivate DAT */
         stnsm   __SF_EMPTY(%r15),0xfb
 
-        /* Switch off lowcore protection */
-        stctg   %c0,%c0,__SF_EMPTY(%r15)
-        ni      __SF_EMPTY+4(%r15),0xef
-        lctlg   %c0,%c0,__SF_EMPTY(%r15)
-
         /* Store prefix register on stack */
         stpx    __SF_EMPTY(%r15)
 
@@ -88,11 +83,6 @@ swsusp_arch_suspend:
         /* Save image */
         brasl   %r14,swsusp_save
 
-        /* Switch on lowcore protection */
-        stctg   %c0,%c0,__SF_EMPTY(%r15)
-        oi      __SF_EMPTY+4(%r15),0x10
-        lctlg   %c0,%c0,__SF_EMPTY(%r15)
-
         /* Restore prefix register and return */
         lghi    %r1,0x1000
         spx     0x318(%r1)
@@ -120,11 +110,6 @@ swsusp_arch_resume:
         /* Deactivate DAT */
         stnsm   __SF_EMPTY(%r15),0xfb
 
-        /* Switch off lowcore protection */
-        stctg   %c0,%c0,__SF_EMPTY(%r15)
-        ni      __SF_EMPTY+4(%r15),0xef
-        lctlg   %c0,%c0,__SF_EMPTY(%r15)
-
         /* Set prefix page to zero */
         xc      __SF_EMPTY(4,%r15),__SF_EMPTY(%r15)
         spx     __SF_EMPTY(%r15)
@@ -178,7 +163,7 @@ swsusp_arch_resume:
         /* Load old stack */
         lg      %r15,0x2f8(%r13)
 
-        /* Pointer to save arae */
+        /* Pointer to save area */
         lghi    %r13,0x1000
 
 #ifdef CONFIG_SMP
@@ -190,11 +175,6 @@ swsusp_arch_resume:
         /* Restore prefix register */
         spx     0x318(%r13)
 
-        /* Switch on lowcore protection */
-        stctg   %c0,%c0,__SF_EMPTY(%r15)
-        oi      __SF_EMPTY+4(%r15),0x10
-        lctlg   %c0,%c0,__SF_EMPTY(%r15)
-
         /* Activate DAT */
         stosm   __SF_EMPTY(%r15),0x04