Re: [PATCH] kexec based hibernation: a prototype of kexecmulti-stage load

From: Huang, Ying
Date: Wed May 14 2008 - 22:34:53 EST


On Wed, 2008-05-14 at 14:43 -0700, Eric W. Biederman wrote:
> "Huang, Ying" <ying.huang@xxxxxxxxx> writes:
>
> >> So, IMHO, for first simple implementation, we don't have to pass around
> >> any data between kernels except entry point. (Please correct me if I am
> >> wrong). Lets get that implementation in first and then we can get rest
> >> of the pieces in place.
> >
> > Yes. Kernel entry/re-entry point is the only information need to be
> > communicated between kernels for just switching between them. So we can
> > focus on kexec jump patch firstly.
>
> Then as a preliminary design let's plan on this.
>
> - Pass the rentry point as the return address (using the C ABI).
> We may want to load the stack pointer etc so we can act as
> a direct entry point for new code.

OK, I will try to do this.

> - Look at passing a pointer to the mapping of pages that the kexec
> trampoline uses in arg1 of the C ABI. Largely the format is defacto
> fixed anyway because we need to pass the structure from C to
> assembly.

You mean pass image->head to purgatory of /sbin/kexec using arg1 of C
ABI?

> Using the standard C ABI makes things much it much easier to pick
> a calling convention, and to document it.

Yes.

Best Regards,
Huang Ying

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