7 files changed, 19 insertions, 18 deletions

diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index 41c211a4d8b1..048450869328 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 generic-y += asm-offsets.h
 generic-y += cacheflush.h
 generic-y += clkdev.h
diff --git a/arch/s390/include/asm/alternative.h b/arch/s390/include/asm/alternative.h
index a72002056b54..c2cf7bcdef9b 100644
--- a/arch/s390/include/asm/alternative.h
+++ b/arch/s390/include/asm/alternative.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_S390_ALTERNATIVE_H
 #define _ASM_S390_ALTERNATIVE_H
 
diff --git a/arch/s390/include/asm/ap.h b/arch/s390/include/asm/ap.h
index c02f4aba88a6..cfce6835b109 100644
--- a/arch/s390/include/asm/ap.h
+++ b/arch/s390/include/asm/ap.h
@@ -1,12 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Adjunct processor (AP) interfaces
  *
  * Copyright IBM Corp. 2017
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License (version 2 only)
- * as published by the Free Software Foundation.
- *
  * Author(s): Tony Krowiak <akrowia@linux.vnet.ibm.com>
  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
  *            Harald Freudenberger <freude@de.ibm.com>
diff --git a/arch/s390/include/asm/bugs.h b/arch/s390/include/asm/bugs.h
index 0f5bd894f4dc..aa42a179be33 100644
--- a/arch/s390/include/asm/bugs.h
+++ b/arch/s390/include/asm/bugs.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  *  S390 version
  *    Copyright IBM Corp. 1999
diff --git a/arch/s390/include/asm/segment.h b/arch/s390/include/asm/segment.h
index 8bfce3475b1c..97a0582b8d0f 100644
--- a/arch/s390/include/asm/segment.h
+++ b/arch/s390/include/asm/segment.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_SEGMENT_H
 #define _ASM_SEGMENT_H
 
diff --git a/arch/s390/include/asm/switch_to.h b/arch/s390/include/asm/switch_to.h
index ec7b476c1ac5..c61b2cc1a8a8 100644
--- a/arch/s390/include/asm/switch_to.h
+++ b/arch/s390/include/asm/switch_to.h
@@ -30,21 +30,20 @@ static inline void restore_access_regs(unsigned int *acrs)
         asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs));
 }
 
-#define switch_to(prev,next,last) do {                                  \
-        if (prev->mm) {                                                 \
-                save_fpu_regs();                                        \
-                save_access_regs(&prev->thread.acrs[0]);                \
-                save_ri_cb(prev->thread.ri_cb);                         \
-                save_gs_cb(prev->thread.gs_cb);                         \
-        }                                                               \
+#define switch_to(prev, next, last) do {                                \
+        /* save_fpu_regs() sets the CIF_FPU flag, which enforces        \
+         * a restore of the floating point / vector registers as        \
+         * soon as the next task returns to user space                  \
+         */                                                             \
+        save_fpu_regs();                                                \
+        save_access_regs(&prev->thread.acrs[0]);                        \
+        save_ri_cb(prev->thread.ri_cb);                                 \
+        save_gs_cb(prev->thread.gs_cb);                                 \
         update_cr_regs(next);                                           \
-        if (next->mm) {                                                 \
-                set_cpu_flag(CIF_FPU);                                  \
-                restore_access_regs(&next->thread.acrs[0]);             \
-                restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);  \
-                restore_gs_cb(next->thread.gs_cb);                      \
-        }                                                               \
-        prev = __switch_to(prev,next);                                  \
+        restore_access_regs(&next->thread.acrs[0]);                     \
+        restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);          \
+        restore_gs_cb(next->thread.gs_cb);                              \
+        prev = __switch_to(prev, next);                                 \
 } while (0)
 
 #endif /* __ASM_SWITCH_TO_H */
diff --git a/arch/s390/include/asm/vga.h b/arch/s390/include/asm/vga.h
index d375526c261f..605dc46bac5e 100644
--- a/arch/s390/include/asm/vga.h
+++ b/arch/s390/include/asm/vga.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_S390_VGA_H
 #define _ASM_S390_VGA_H