s390: add support for vector extension

The vector extension introduces 32 128-bit vector registers and a set of
instruction to operate on the vector registers.

The kernel can control the use of vector registers for the problem state
program with a bit in control register 0. Once enabled for a process the
kernel needs to retain the content of the vector registers on context
switch. The signal frame is extended to include the vector registers.
Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added
to the regset interface for the debugger and core dumps.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 210e1285f75a..db96b418160a 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -20,6 +20,7 @@
 #include <asm/cputime.h>
 #include <asm/nmi.h>
 #include <asm/crw.h>
+#include <asm/switch_to.h>
 
 struct mcck_struct {
         int kill_task;
@@ -163,6 +164,21 @@ static int notrace s390_revalidate_registers(struct mci *mci)
                         "       ld      15,120(%0)\n"
                         : : "a" (fpt_save_area));
         }
+
+#ifdef CONFIG_64BIT
+        /* Revalidate vector registers */
+        if (MACHINE_HAS_VX && current->thread.vxrs) {
+                if (!mci->vr) {
+                        /*
+                         * Vector registers can't be restored and therefore
+                         * the process needs to be terminated.
+                         */
+                        kill_task = 1;
+                }
+                restore_vx_regs((__vector128 *)
+                                S390_lowcore.vector_save_area_addr);
+        }
+#endif
         /* Revalidate access registers */
         asm volatile(
                 "       lam     0,15,0(%0)"