1 files changed, 16 insertions, 14 deletions

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index ef86ad24398..ae0e14b8880 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -47,29 +47,31 @@ enum s390_regset {
 
 void update_per_regs(struct task_struct *task)
 {
-        static const struct per_regs per_single_step = {
-                .control = PER_EVENT_IFETCH,
-                .start = 0,
-                .end = PSW_ADDR_INSN,
-        };
         struct pt_regs *regs = task_pt_regs(task);
         struct thread_struct *thread = &task->thread;
-        const struct per_regs *new;
-        struct per_regs old;
-
-        /* TIF_SINGLE_STEP overrides the user specified PER registers. */
-        new = test_tsk_thread_flag(task, TIF_SINGLE_STEP) ?
-                &per_single_step : &thread->per_user;
+        struct per_regs old, new;
+
+        /* Copy user specified PER registers */
+        new.control = thread->per_user.control;
+        new.start = thread->per_user.start;
+        new.end = thread->per_user.end;
+
+        /* merge TIF_SINGLE_STEP into user specified PER registers. */
+        if (test_tsk_thread_flag(task, TIF_SINGLE_STEP)) {
+                new.control |= PER_EVENT_IFETCH;
+                new.start = 0;
+                new.end = PSW_ADDR_INSN;
+        }
 
         /* Take care of the PER enablement bit in the PSW. */
-        if (!(new->control & PER_EVENT_MASK)) {
+        if (!(new.control & PER_EVENT_MASK)) {
                 regs->psw.mask &= ~PSW_MASK_PER;
                 return;
         }
         regs->psw.mask |= PSW_MASK_PER;
         __ctl_store(old, 9, 11);
-        if (memcmp(new, &old, sizeof(struct per_regs)) != 0)
-                __ctl_load(*new, 9, 11);
+        if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
+                __ctl_load(new, 9, 11);
 }
 
 void user_enable_single_step(struct task_struct *task)