On Thu, Oct 13, 2011 at 8:40 PM, Andrew Lutomirski <luto@mit.edu> wrote:
>
> How does that work?  The tricky case is when one of those three words
> spans a page boundary if the access to the first page is valid, but
> the access to the second page is not.  When that happens, if we report
> the fault as coming from the first page, then UML is likely to get
> think the fault was spurious and enter an infinite loop.

Hmm. Gaah, I just find that memcpy loop disgusting.

We already have that ugly "uaccess_error" crap in handle_exception(),
we might as well do something like the attached and just say "hey, now
you can catch the page fault information for a get_user/put_user
fault".

Isn't that much nicer?

You don't even have to check each word, you can just take the last
exception info from the thread-info.

              Linus