Re: [PATCH 1/2] init: Introduce early initrd files through uncompressedcpio passing

From: H. Peter Anvin
Date: Mon Jul 23 2012 - 11:09:25 EST

On 07/23/2012 07:40 AM, Thomas Renninger wrote:
This is another problem and I expect I call:
early enough for Fenghua's needs.
If not, how early exactly is this needed?

We're calling that from arch-specific code before even turning paging on. This has a couple of consequences:

1. ALL STATIC POINTERS ARE FORBIDDEN. Period. The code must be able to be executed from a nonstandard linear address, and any static pointer (like a function pointer) breaks that.

2. Any ideas of doing everything at the same time, or uniform architecture, is clearly out the window... we're just barely capable of using C at this point at all.

Now, you definitely do have a valid point about being able to iterate over multiple files with a common prefix. We could do that with either a callback (where the callback is passed in as an argument), but I think it might be nicer to do that as an iterator interface... let me ketch on this.

If (just an example) CPU microcode files get passed via "early initrd",
the same path could be provided than needed by request_fw().

This will all be obsolete. request_fw is available way, way, way too late.

H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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