s390/kprobes: add exrl to list of prohibited opcodes

"execute relative long" may have all sorts of side effects dependend on
the instructions it executes.
Therefore prohibit setting a kprobe on exrl just like we do for the
regular execute instruction.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 0ce9fb245034..d86e64eddb42 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -67,6 +67,11 @@ static int __kprobes is_prohibited_opcode(kprobe_opcode_t *insn)
         case 0xac:      /* stnsm */
         case 0xad:      /* stosm */
                 return -EINVAL;
+        case 0xc6:
+                switch (insn[0] & 0x0f) {
+                case 0x00: /* exrl   */
+                        return -EINVAL;
+                }
         }
         switch (insn[0]) {
         case 0x0101:    /* pr    */
@@ -180,7 +185,6 @@ static int __kprobes is_insn_relative_long(kprobe_opcode_t *insn)
                 break;
         case 0xc6:
                 switch (insn[0] & 0x0f) {
-                case 0x00: /* exrl   */
                 case 0x02: /* pfdrl  */
                 case 0x04: /* cghrl  */
                 case 0x05: /* chrl   */