Re: Recovery kernel and application crashes how?

Hi Carl,
Thanks for the info.
Much useful

/Prem

On 5/10/07, Carl van Schaik <[email protected]> wrote:
>
> Hi Prem,
>
> 1. A thread accessing memory that is not mapped or does not have
> suitable permissions generates a pagefault. Pagefaults are delivered on
> behalf of the thread to that threads "pager", a different thread setup
> to handle these. The page may then perform operations to map pages to
> the thread's address space or kill the thread etc.
>
> 2. Drivers in L4 are typically servers or libraries run at user level,
> thus a driver faulting has the same behavior as above.
> The L4 kernel is small and thus it is easier to prevent kernel bugs.
> L4Ka does not handle kernel faults such as null pointer dereferences,
> like many kernels, it is not recoverable.
>
> 3. Threads can only access memory in their own address space, it is not
> possible for a thread to access a different address space. If no
> mappings exist at am attempted address, a pagefault is generated as in 1
> above.
>
> regards,
> Carl
>
> [email protected] wrote:
> > Date: Thu, 10 May 2007 09:19:02 +0530
> > From: "Prem Mallappa" <[email protected]>
> > Subject: Recovery kernel and application crashes how?
> > To: [email protected]
> > Message-ID:
> >       <[email protected]>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > Hi All,
> > I am interested to know the behaviour of L4Ka in the following
> conditions.
> >
> > 1. Thread (or task) trying to access unmapped memory (null pointer
> > dereference)
> > 2. Kernel/driver trying to access unmapped memory (null pointer
> dereference)
> > 3. Thread (or task) trying to access memory mapped to other process (may
> not
> > holds good for l4 since each thread has its own address space).
> >
> > And how the recover from such exceptions(errors) are done.
> >
> > Thanks
> > Prem
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL:
> http://lists.ira.uni-karlsruhe.de/pipermail/l4ka/attachments/20070510/cf306f16/attachment-0001.html
> >
> > ------------------------------
> >
> > _______________________________________________
> > l4ka mailing list
> > [email protected]
> > https://lists.ira.uni-karlsruhe.de/mailman/listinfo/l4ka
> >
> >
> > End of l4ka Digest, Vol 41, Issue 1
> > ***********************************
> >
>
>