Re: amd64: kernel aslr support

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Oct 04, 2017 at 06:59:02PM -0400, Mouse wrote:
> > Here is a Kernel ASLR implementation for NetBSD-amd64.  [...]
> 
> > Contrary to what has been said in previous discussions, KASLR does
> > not alter debugability in any way: the symbols are still mapped in
> > memory as they are right now, and ddb resolves them as usual.
> 
> I disagree that that's enough to "not alter debugability in any way".
> It makes common debugging tasks work, perhaps, but I have occasionally
> run into cases where all I have is a pc value (even less often, but
> it's still happened, a data address) and have had nothing but /netbsd's
> symbol table to help me make sense of it.

Sure. One common case is Xen.

It may also alter reproductablility, in case of pointer bug in the kernel.

I think the base address of each section should be printed to console at boot,
so that with a serial console log we can make sense of the addresses.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--