+void unreg_prof_syscall_enter(char *name)
+{
+ int num;
+
+ num = syscall_name_to_nr(name);
+ if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+ return;
+
+ mutex_lock(&syscall_trace_lock);
+ sys_prof_refcount_enter--;
+ clear_bit(num, enabled_prof_enter_syscalls);
+ if (!sys_prof_refcount_enter)
+ unregister_trace_sys_enter(prof_syscall_enter);
+ mutex_unlock(&syscall_trace_lock);
+}
+
+static void prof_syscall_exit(struct pt_regs *regs, long ret)
+{
+ struct syscall_metadata *sys_data;
+ struct syscall_trace_exit rec;
+ int syscall_nr;
+
+ syscall_nr = syscall_get_nr(current, regs);
+ if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
+ return;
+
+ sys_data = syscall_nr_to_meta(syscall_nr);
+ if (!sys_data)
+ return;
+
+ tracing_generic_entry_update(&rec.ent, 0, 0);
+ rec.ent.type = sys_data->exit_id;
+ rec.nr = syscall_nr;
+ rec.ret = syscall_get_return_value(current, regs);
+
+ perf_tpcounter_event(sys_data->exit_id, 0, 1, &rec, sizeof(rec));
+}
+
+int reg_prof_syscall_exit(char *name)
+{
+ int ret = 0;
+ int num;
+
+ num = syscall_name_to_nr(name);
+ if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+ return -ENOSYS;
+
+ mutex_lock(&syscall_trace_lock);
+ if (!sys_prof_refcount_exit)
+ ret = register_trace_sys_exit(prof_syscall_exit);
+ if (ret) {
+ pr_info("event trace: Could not activate"
+ "syscall entry trace point");
+ } else {
+ set_bit(num, enabled_prof_exit_syscalls);
+ sys_prof_refcount_exit++;