Re: [patch] x86: fix ESP corruption CPU bug

[Brian Gerst]

linux-os wrote:
> On Mon, 14 Mar 2005, Jakob Eriksson wrote:
>
> > Andi Kleen wrote:
> >
> > > Stas Sergeev <stsp@xxxxxxxx> writes:
> > >
> > > > > Another way of saying the same thing: I absolutely hate seeing
> > > > > patches that fix some theoretical issue that no Linux apps will ever
> > > > > care about.
> > > > No, it is not theoretical, but it is mainly
> > > > about a DOS games and an MS linker, as for
> > > > me. The things I'd like to get working, but
> > > > the ones you may not care too much about:)
> > > > The particular game I want to get working,
> > > > is "Master of Orion 2" for DOS.
> > >
> > > How about you just run it in dosbox instead of dosemu ?
> >
> > Yes, that's a solution of course, but it is a bit like saying why
> > not use Open Office instead of MS Word.
> >
> > A long term goal of wine is to support DOS apps to. Of course
> > it's not a priority, but it's there.
> >
> > regards,
> > Jakob
>
> Can you tell me how the invisible high-word (invisible in VM-86, and
> in real mode) could possibly harm something running in VM-86 or
> read-mode ???  I don't even think it's a BUG. If the transition
> into and out of VM-86 doesn't handle the fact that the high-word
> of the stack hasn't been used in VM-86, then that piece of code
> is bad (the SP isn't even the same stack, BTW).

Because even in 16-bit mode (real, vm86 or 16-bit protected) you can use 
32-bit instructions, with an operand and/or address size override 
prefix.  Of course this only works on 386 or later.

--
				Brian Gerst
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