Messages in this thread | | | Date | Wed, 06 Feb 2002 13:17:29 -0800 | From | "H. Peter Anvin" <> | Subject | Re: kernel: ldt allocation failed |
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Jakub Jelinek wrote:
>>> >>x86-64, interestingly, retains vestigial meaning of the %fs and %gs >>registers (but no others) to use as a base pointer for this reason >>alone. > > Well, on x86-64 this is purely x86-64 ABI designers decision, they could > pick one of %r8 - %r15 and use that as thread pointer instead (and were > recommended to do so). >
Wasting an architectural register is still bloody expensive, even if 1 among 16 is less than 1 among 8. They'll be using %gs as thread pointer in userspace and CPU pointer in kernel space.
-hpa
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