user per registers vs. ptrace single stepping

[android-x86/kernel.git] / arch / s390 / kernel / ptrace.c

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index ef86ad2..ae0e14b 100644 (file)
--- 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)