- lock_kernel();
-
- if (first_call) {
- /* Set WPC.DBRMODE to 0. This makes all debug events get
- * delivered through RESVEC, i.e. into the handlers in entry.S.
- * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
- * would normally be left set to 1, which makes debug events get
- * delivered through DBRVEC, i.e. into the remote gdb's
- * handlers. This prevents ptrace getting them, and confuses
- * the remote gdb.) */
- printk("DBRMODE set to 0 to permit native debugging\n");
- poke_real_address_q(WPC_DBRMODE, 0);
- first_call = 0;
- }
-
- ret = -EPERM;
- if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED)
- goto out;
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
- ret = 0;
- goto out;
- }
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
- goto out;
-
- ret = -EPERM;
- if (pid == 1) /* you may not mess with init */
- goto out_tsk;
-
- if (request == PTRACE_ATTACH) {
- ret = ptrace_attach(child);
- goto out_tsk;
- }
-
- ret = ptrace_check_attach(child, request == PTRACE_KILL);
- if (ret < 0)
- goto out_tsk;
-