Date: Wed, 31 Oct 2007 09:00:38 -0400 From: "Andrew Duane" <aduane@juniper.net> To: <freebsd-hackers@freebsd.org> Subject: RE: ``Stopping RAM access'' Message-ID: <0FCFCF6165E968449991746EB91D614DB13F64@antipi.jnpr.net> In-Reply-To: <319cceca0710301402j48355b54gc572f9c76a39d5a8@mail.gmail.com> References: <0862634D7E37134986CB15DF2E4542BA1C1EE5@sbssrv.SALAG.local> <319cceca0710301402j48355b54gc572f9c76a39d5a8@mail.gmail.com>
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Well, if the system stops accessing RAM, you had better make sure that = *all* the instructions you need are already loaded into the L1 and L2 = caches. Otherwise you won't be able to turn RAM back on. That would = involve carefully preloading everything through use of the system's = appropriate PREFETCH calls, locking down the cache lines to make sure = nothing else disturbs them, turning off interrupts, and probably more. To actually turn off RAM, you'd have to power down or otherwise disable = the memory controller interface on your board. The procedures for that = would be highly platform dependent. /Andrew =20 > -----Original Message----- > From: owner-freebsd-hackers@freebsd.org [mailto:owner-freebsd- > hackers@freebsd.org] On Behalf Of Maslan > Sent: Tuesday, October 30, 2007 5:02 PM > To: Jaroszewski =A3ukasz > Cc: freebsd-hackers@freebsd.org > Subject: Re: ``Stopping RAM access'' >=20 > > Can anyone give me a clue, how one can ``stop'' system from = accessing > > RAM, and then allow it again?
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