On Fri, Oct 12, 2007 at 07:54:16PM -0700, Matthew Dillon wrote:
quoted text
>     (1) We can map a page containing the address of the per-cpu globaldata
>         structure and use %fs in the trap code:
>  
>         movq	$SOME_FIXED_CONSTANT_ADDRESS,%fs

You don't have to play such games on AMD64 -- the swapgs instruction is
normally used by traps and system calls to load a well-defined address
base for that. Note that gs is expected to be used for, but that is a
minor detail.

Joerg