Re: Boot failure in 2.5.31 BK with new TLS patch

[Gabriel Paubert <paubert@iram.es>]

James Bottomley wrote:

> 
> 
> Actually, the intel manual recommends (but doesn't require) a wierd alignment 
> for the descriptors.  It recommends aligning them at an address which is 2 MOD 
> 4 to avoid possible alignment check faults in user mode.  Not that I think we 
> can ever run into the problem, but we should probably obey the recommendation. 
>  I'll fix this up as well.

This is already done for the IDT descriptor, but not (yet) for the gdt 
descriptor(s).

Alignment checks are only done when CPL==3. And lidt/lgdt are (obviously) 
privileged, although sidt/sgdt (and sldt/str for that matter) are not,
but I can't see how application could take benefit or make malicious use
of this capability.

	Gabriel.