FOR REVIEW: New x86-64 vsyscall vgetcpu()
Jakub Jelinek
jakub@redhat.com
Fri Jun 16 16:25:00 GMT 2006
On Fri, Jun 16, 2006 at 05:37:06PM +0200, Andi Kleen wrote:
> On Friday 16 June 2006 17:31, Zoltan Menyhart wrote:
> > Andi Kleen wrote:
> >
> > > That is not how user space TLS works. It usually has a base a register.
> >
> > Can you please give me a real life (simplified) example?
>
> On x86-64 it's just %fs:offset. gcc is a bit dumb on this and usually
> loads the base address from %fs:0 first.
GCC is not dumb, unless you force it with -mno-tls-direct-seg-refs.
Guess you are bitten by SUSE GCC hack which makes -mno-tls-direct-seg-refs
the default (especially on x86-64 it is a really bad idea).
Jakub
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