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Subject: Re: kexec (was: [lkcd-devel] Re: What's left over.)
From: Andy Pfiffer <andyp@osdl.org>
To: landley@trommello.org
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On Thu, 2002-11-07 at 21:36, Rob Landley wrote:

> It strikes me that "load a blob of data into physical memory and keep it there 
> until further notice" is actually relatively generic mechanism, and something 
> there might be other reasons for root or various devices to do.  (DSPs that 
> want their firmware in system ram?  3D models and textures for an onboard 
> video card?)  If I'm wrong, would somebody be kind enough to tell me why?
> 
> Rob


Yes, that is rather generic -- somewhat like a variable-sized ramdisk.  

I think the key difference is that the ramdisk wants to hold blobs of
data that will be accessed from user-mode by read & write.

A "blob of bytes" for kexec, and maybe for a few other uses, wants to be
accessed (perhaps a page at a time) by pointers while in kernel space.

I'm not so sure of the generality, though.  It's my guess that there
many special-case requirements that might make it difficult to become
useful infrastructure (eg, maybe the DSP on a soundcard needs it to be
4M aligned and contiguous, or the texture memory for the video card
wants to be able to walk a data structure that only it knows about).

Andy




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