1 files changed, 12 insertions, 8 deletions

diff --git a/arch/s390/include/asm/system.h b/arch/s390/include/asm/system.h
index 1f2ebc4afd82..c35d0a383f00 100644
--- a/arch/s390/include/asm/system.h
+++ b/arch/s390/include/asm/system.h
@@ -85,14 +85,18 @@ static inline void restore_access_regs(unsigned int *acrs)
         asm volatile("lam 0,15,%0" : : "Q" (*acrs));
 }
 
-#define switch_to(prev,next,last) do {                                       \
-        if (prev == next)                                                    \
-                break;                                                       \
-        save_fp_regs(&prev->thread.fp_regs);                                 \
-        restore_fp_regs(&next->thread.fp_regs);                              \
-        save_access_regs(&prev->thread.acrs[0]);                             \
-        restore_access_regs(&next->thread.acrs[0]);                          \
-        prev = __switch_to(prev,next);                                       \
+#define switch_to(prev,next,last) do {                                  \
+        if (prev == next)                                               \
+                break;                                                  \
+        if (prev->mm) {                                                 \
+                save_fp_regs(&prev->thread.fp_regs);                    \
+                save_access_regs(&prev->thread.acrs[0]);                \
+        }                                                               \
+        if (next->mm) {                                                 \
+                restore_fp_regs(&next->thread.fp_regs);                 \
+                restore_access_regs(&next->thread.acrs[0]);             \
+        }                                                               \
+        prev = __switch_to(prev,next);                                  \
 } while (0)
 
 extern void account_vtime(struct task_struct *, struct task_struct *);