[S390] fix loading of PER control registers for utrace.

If the current task enables / disables PER tracing for itself the
PER control registers need to be loaded in FixPerRegisters.

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

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 13815d39f7d..7cf46423441 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -65,6 +65,7 @@ FixPerRegisters(struct task_struct *task)
 {
         struct pt_regs *regs;
         per_struct *per_info;
+        per_cr_words cr_words;
 
         regs = task_pt_regs(task);
         per_info = (per_struct *) &task->thread.per_info;
@@ -98,6 +99,13 @@ FixPerRegisters(struct task_struct *task)
                 per_info->control_regs.bits.storage_alt_space_ctl = 1;
         else
                 per_info->control_regs.bits.storage_alt_space_ctl = 0;
+
+        if (task == current) {
+                __ctl_store(cr_words, 9, 11);
+                if (memcmp(&cr_words, &per_info->control_regs.words,
+                           sizeof(cr_words)) != 0)
+                        __ctl_load(per_info->control_regs.words, 9, 11);
+        }
 }
 
 void user_enable_single_step(struct task_struct *task)