What is trampoline.S for?

[BVK]

On 3/9/06, Espen Skoglund <esk at ira.uka.de> wrote:
> In some cases that kernel creates some form of "asynchronous event"
> for another thread.  This is implemented by creating a new stack frame
> on the kernel stack of that thread.  The next time this thread is
> activated, the context described by this new stack frame is started.
So this is purely inside kernel, using kernel stack, and i hope it
will not affect user-level threads in any way, i mean, user-level
threads need not know about this at all.

    My problem was, i am getting pagefaults in zero-th page, even
before a thread starts executing its first instruction.  Is such a
case possible in pistachio?  When i was looking at chacmos source, its
pager's are mapping trampoline.S to *every* thread, at zero-th page
location.  So i thought trampoline.S has something to do with these
*pagefaults-in-zero-th-page*.

    So, my question is, 'is it possible to get pagefaults from a new
thread, even before executing it start execution?'

thanks,
-bvk.