Re: [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE*

[H. Peter Anvin]

On 04/28/2014 08:45 PM, H. Peter Anvin wrote:
> 
> OK, so I found a bug in ldttest.c -- it sets CS to an LDT segment, but
> it never sets SS to an LDT segment.  This means that it should really
> have zero footprint versus the espfix code, and implies that we instead
> have another bug involved.  Why the espfix code should have any effect
> whatsoever is a mystery, however... if it indeed does?
> 
> I have uploaded a fixed ldttest.c, but it seems we might be chasing more
> than that...
> 

In particular, I was already wondered how we avoid an "upside down
swapgs" with a #GP on IRET.  The answer might be that we don't...

	-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/