Re: Need help in understanding x86 syscall

Coywolf Qi Hunt
2005-08-12T05:30:28Z

On 8/12/05, Jeff Carr <jcarr@linuxmachines.com> wrote:
> On 08/11/2005 10:18 AM, Steven Rostedt wrote:
>
> > It's vanilla 2.6.12-rc3 + Ingo's RT V0.7.46-02-rs-0.4 + some of my own
> > customizations. But I never touched the sysentry stuff and with a few
> > printks I see it is being initialized.
> >
> >>Also glibc support.
> >
> > I'm using Debian unstable with a recent (last week) update.
> >
> > -- Steve
>
> But are you using libc6-i686? That enables NPTL. Perhaps the behavior
> difference is there? I'm surprised int 80 doesn't really cause an
> interrupt; it doesn't jump to the appropriate place in the x86 vector
> table? Interesting.
>
> Jeff
>
>
> root@jcarr:~# dpkg -s libc6-i686
> ...
> This set of libraries is optimized for i686 machines, and will only be
> used if you are running a 2.6 kernel on an i686 class CPU (check the
> output of `uname -m'). This includes Pentium Pro, Pentium II/III/IV,
> Celeron CPU's and similar class CPU's (including clones such as AMD
> Athlon/Opteron, VIA C3 Nehemiah, but not VIA C3 Ezla).
> .
> This package includes support for NPTL.
> .

Even with libc6-i686 installed, I can't see sysenter got used.
libc6-i686 has /lib/tls/i686/cmov/libc.so.6, not the one
/lib/libc-2.3.5.so.

mozilla gets: Illegal instruction

I've added ud2 in both entry.S and vsyscall-sysenter.S.

Any ideas?

--
Coywolf Qi Hunt