Re: FOR REVIEW: New x86-64 vsyscall vgetcpu()

Jakub Jelinek
2006-06-16T16:33:15Z

On Fri, Jun 16, 2006 at 06:24:52PM +0200, Andi Kleen wrote:
> I wonder why it happened on x86-64 though - i thought there were no negative
> offsets on x86-64 TLS.

It uses negative offsets for __thread vars and positive are reserved for
implementation (i.e. glibc). But as %fs in 64-bit programs is just
msr 0xc0000100 base addition, with no segment limit, neither Xen nor VMWare
can play limit tricks with it.

Jakub