Re: [PATCH V5] x86: NX protection for kernel data

From: Ingo Molnar
Date: Tue Oct 13 2009 - 10:17:23 EST



* Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

> On Tue, 13 Oct 2009 07:35:28 -0400
> Siarhei Liakh <sliakh.lkml@xxxxxxxxx> wrote:
>
> > ---[ Kernel Mapping ]---
> > 0xc0000000-0xc0100000 1M RW GLB x pte
> > -0xc0100000-0xc048d000 3636K ro GLB x pte
> > -0xc048d000-0xc04d0000 268K RW GLB x pte
> > -0xc04d0000-0xc04d2000 8K RW GLB NX pte
> > -0xc04d2000-0xc04d3000 4K RW GLB x pte
> > -0xc04d3000-0xc0531000 376K RW GLB NX pte
> > -0xc0531000-0xc0600000 828K RW GLB x pte
> > +0xc0100000-0xc0381000 2564K ro GLB x pte
> > +0xc0381000-0xc048d000 1072K ro GLB NX pte
> > +0xc048d000-0xc0600000 1484K RW GLB NX pte
> > 0xc0600000-0xf7800000 882M RW PSE GLB NX pmd
> > 0xf7800000-0xf79fe000 2040K RW GLB NX pte
> > 0xf79fe000-0xf7a00000 8K pte
> > ===============================================
> >
>
> looks great to me; the result is
> * kernel is ro + x
> * rodata is ro + NX
> * data is RW + NX
>
> (and there is no "RW + x", other than the first megabyte... hmm. maybe
> we need to look at that as well at some point)

Could we cover the first megabyte too please via a (default-disabled)
option? Modern Xorg shouldnt mind about that anymore, right?

Ingo
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