ARM processor mode, kernel startup, Hyp / secure state

Ian Jackson Ian.Jackson at
Tue Aug 23 13:57:43 EDT 2011

Russell King - ARM Linux writes ("Re: ARM processor mode, kernel startup, Hyp / secure state"):
> On Tue, Aug 23, 2011 at 06:18:37PM +0100, Ian Jackson wrote:
> > Yes.  But in the future it will do, surely ?  I mean, we're working on
> > bootloader protocols and this part (to do with startup cpu states and
> > ownership of the various privilege levels) is only part of it.
> No - at least not yet, and I don't see any reason why we'd ever want to
> use raw ELF.
> The problem with ELF is that it carries lots of baggage around which
> platforms just don't need.  Fine if it's on a hard disk and you're
> booting a desktop, but not for embedded where space tends to be a
> premium.

Hrm, yes.

> Plus, I'd point out that _no one_ is talking about boot protocols.  Not
> outside linaro at any rate.  Which means that they're doing effective
> closed-door discussion.

I'm not sure whether by "outside linaro" you mean "outside some kind
of top secret Linaro meetings".  I went to an open meeting of Linaro
developers touching on exactly these kind of topics, and everything
was public and there was substantial interest.

I'm not a Linaro developer; but I have CC'd their boot-architecture
list which AIUI is where some of the Linaro folks were thinking of
discussing boot protocols.

Just to be clear: I don't have a particular axe to grind, except that
I would like there to be some kind of defined and reasonably stable
interface, and that obviously we ( need that interface to
support access to Hyp mode (which is something that Linux needs too if
we are to have a properly supported KVM on ARM).

Are linux-arm-kernel at infradead and boot-architecture at linaro the right
places to try to have this conversation ?


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