Re: [PATCH RFC 1/7] x86/head/64: Mark startup_gdt and startup_gdt_descr as __initdata

[Josh Poimboeuf]

On Wed, Oct 18, 2023 at 01:45:40PM +0200, Ingo Molnar wrote:
> 
> * H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> 
> > If the goal is better KASLR, then what we really should spend time on was 
> > Kristen Accardi's fgKASLR patches, which not only exponentially(!) 
> > increases the randomization entrophy but also *actually* avoids the "one 
> > leak and it's over" problem.
> 
> Agreed. Going by this version of function-granularity KASLR from 3 years 
> ago:
> 
>   https://lwn.net/Articles/824307/
>   https://lwn.net/ml/linux-kernel/20200623172327.5701-1-kristen@xxxxxxxxxxxxxxx/
> 
> The fgKASLR feature looks entirely viable to me. Back then I presumed it 
> would get iterated beyond v3, and then it fell off my radar. :-/
> 
> If Kristen or someone else would like to dust this off & submit a fresh 
> version it would be much appreciated!

That actually got up to v10:

  https://lkml.kernel.org/lkml/20220209185752.1226407-1-alexandr.lobakin@xxxxxxxxx

Anyway, I'm also very interested in this.  If nobody else is working on
it then I could give it a try.

BTW I've wondered if translation-unit granularity would be more
preferable than function granularity due to improved i-cache locality
and (possibly) easier livepatch compatibility.

-- 
Josh