Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6

* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
  [S390] zcrypt: fix scheduling of hrtimer ap_poll_timer
  [S390] vdso: clock_gettime of CLOCK_THREAD_CPUTIME_ID with noexec=on
  [S390] vdso: fix per cpu area allocation
  [S390] hibernation: fix register corruption on machine checks
  [S390] hibernation: fix lowcore handling

1 files changed, 24 insertions, 12 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();
 }