Re: [PATCH 1/3] x86_64: further cleanup of 32-bit compat syscallmechanisms

From: H. Peter Anvin
Date: Sun Jul 13 2008 - 20:00:33 EST


Jeremy Fitzhardinge wrote:
AMD only supports "syscall" from 32-bit compat usermode.
Intel and Centaur(?) only support "sysenter" from 32-bit compat usermode.

Set the X86 feature bits accordingly, and set up the vdso in
accordance with those bits. On the offchance we run on in a 64-bit
environment which supports neither syscall nor sysenter from 32-bit
mode, then fall back to the int $0x80 vdso.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

Acked-by: H. Peter Anvin <hpa@xxxxxxxxx>

-hpa

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