Re: Pagefault return path

Hi Christian,

The code in the kernel should return after the sys_ipc() function call 
in do_ipc(), called from send_pagefault_ipc(). Or, if the IPC was 
canceled, the tcb_t::unwind() function will fix up the thread's state 
and return the thread to user mode.

Note, at a low level, the replying handler thread will at some stage do 
a switch_to() to the originator thread which will jump into the middle 
of sys_ipc() where the originator thread performed the original 
switch_to() to to the handler thread.

regards,
Carl

[email protected] wrote:
> Message: 1
> Date: Thu, 22 Mar 2007 11:12:33 +0100
> From: "Christian, Martin, OPEE45" <[email protected]>
> Subject: Pagefault return path
> To: <[email protected]>
> Message-ID:
> 	<[email protected]>
> Content-Type: text/plain;	charset="us-ascii"
>
> Hi!
> I'm currently looking at the execution path taken by the kernel on a
> page fault. It's more or less clear to me how it enters the kernel and
> sends a pagefault IPC. However, the return path taken where the user
> mode Pager responds is a bit more hidden. I was looking for something
> like "if IPC == pagefault answer) then ..." in the IPC code. Maybe
> someone could point out the relevant areas?! The places where the book
> keeping is done - or more precisely where a mapped/granted page is
> inserted into the page dictionary of an address space.
>
> Thanks,
>
> Martin.
>
>
>
>
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