linux-kernel - RE: NonExecutable Bit in 32Bit

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Message-ID: <F7F9B0BE3E9BD449B110D0B1CEF6CAEF0530264B@ABGEX01E.abg.fsc.net>
Date:	Wed, 25 Apr 2007 08:58:33 +0200
From:	"Cestonaro, Thilo \(external\)" 
	<Thilo.Cestonaro.external@...itsu-siemens.com>
To:	"Tuncer Ayaz" <tuncer.ayaz@...il.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: RE: NonExecutable Bit in 32Bit

> > > > CONFIG_HIGHMEM64G=y
> > > > CONFIG_HIGHMEM=y
> > > > CONFIG_X86_PAE=y
> > >
> > > Ok in highmem it's active, whats about lowmem?
> > > x86-64 is NX active for lowmem too AFAIK.
> >
> > It's more of an issue of having PAE enabled.
> > Without PAE you are not able to use the the NX bit.
> That's the way the CPU works, not Linux.
> 
> Forgot to add:
> from arch/i386/Kconfig:
> config X86_PAE
> 	bool
> 	depends on HIGHMEM64G
> 	default y
> 	select RESOURCES_64BIT
> 
> > Hope this helps.
> >

Just that I get it right, NX just works with PAE enabled, and PAE just works with HIGHMEM64G enabled.
And this prevents the lowmemory to be secured by NX?

Ciao Thilo
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