Re: Linux i386 clone(): %ebx 'frobbing' ?

From: Ahmed S. Darwish
Date: Fri Feb 15 2008 - 18:56:47 EST


On Sat, Feb 16, 2008 at 12:28:11AM +0100, Andreas Schwab wrote:
> "Ahmed S. Darwish" <darwish.07@xxxxxxxxx> writes:
>
> > Hi Andreas,
> >
> > On Fri, Feb 15, 2008, Andreas Schwab wrote:
> >> "Ahmed S. Darwish" <darwish.07@xxxxxxxxx> writes:
> >>
> >> > I don't understand how the `fn' argument reached the child thread
> >> > in the %ebx register. It's said in the comment that `fn' will be
> >> > popped to child 'in the ebx frobbing below'. But what does that mean ?
> >>
> >> See "popl %ebx" after "int $0x80".
> >>
> >
> > I hope I'm not misreading something obvious, but I can't find
> > the code where FUNC(%esp) is stored in %ebx before %ebx value
> > got pushed in the stack (and restored in above 'popl' statement).
>
> It is stored in the new stack for the child, as explained in the
> comment. The parent has a different stack.
>

Ooh great, I got it. Sorry, my mind didn't connect the dots though
I read the comment several times. Thanks a lot for bearing with me :).

Regards,

--
Ahmed S. Darwish
Homepage: http://darwish.07.googlepages.com
Blog: http://darwish-07.blogspot.com

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