Linux ARM, does schedule() jumps to user space ?

Hi,

A very basic question.
AFAIK schedule() selects the next process to run.
Now once it has selected the process, and say if the process is a user
space or kernel space one. how does the switch to user happens,

a) Is it in schedule function . it has to be a arch level function
called from schedule()

b) or Else where, so is there a umberlla function like

somefunc()
{
task_ptr = schedule();
switch_to(task_ptr)

...

}

Can someone explain this