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To: Andy Pfiffer <andyp@osdl.org>
Cc: landley@trommello.org, Linus Torvalds <torvalds@transmeta.com>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
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Subject: Re: kexec (was: [lkcd-devel] Re: What's left over.)
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From: ebiederm@xmission.com (Eric W. Biederman)
Date: 11 Nov 2002 11:25:06 -0700
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Andy Pfiffer <andyp@osdl.org> writes:

> 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.

kexec at least at the end, and probably for earlier for handling
panics wants code to be in a very specific location in ram. 

If you want to hook the functionality behind in behind kexec_load,
when say KEXEC_FIXED is passed as a flag, go ahead.  There is enough
other setup to jump to the code loaded into memory that "load a blob
of data into physical memory and keep it there" is not a sufficient
interface.

In the general case I using some kind of scatter gather list seems
the most polite way to go.

Eric
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