Re: [PATCH] mm/x86: AMD Bulldozer ASLR fix

[Ingo Molnar]

* Hector Marco-Gisbert <hecmargi@xxxxxx> wrote:

> A bug in Linux ASLR implementation which affects some AMD processors 
> has been found. The issue affects to all Linux process even if they 
> are not using shared libraries (statically compiled).

It's not a bug, it's a feature: to work around a Bulldozer cache 
aliasing performance problem we have to keep bits 12,13,14 equal for 
all mappings in the system.

Your patch improves upon that fix: by per-boot randomizing the 
constant portion of the randomized range.

Btw., does anyone know how relevant the performance fix is these days? 
A simpler improvement would be to remove the workaround altogether and 
recover proper randomization of bits 12,13,14.

Thanks,

	Ingo
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