Re: RFC: userspace exception fixups

[Andy Lutomirski]

On Mon, Nov 19, 2018 at 8:02 AM Jarkko Sakkinen
<jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
>
> On Mon, Nov 19, 2018 at 07:29:36AM -0800, Andy Lutomirski wrote:
> > 1. The kernel needs some way to know *when* to apply this fixup.
> > Decoding the instruction stream and doing it to all exceptions that
> > hit an ENCLU instruction seems like a poor design.
>
> I'm not sure why you would ever need to do any type of fixup as the idea
> is to just return to AEP i.e. from chosen exceptions (EPCM, #UD) the AEP
> would work the same way as for exceptions that the kernel can deal with
> except filling the exception information to registers.

Sure, but how does the kernel know when to do that and when to send a
signal?  I don't really like decoding the instruction stream to figure
it out.