Re: [BROKEN PATCH] kexec for ia64

[Jesse Barnes <jbarnes@engr.sgi.com>]

On Wednesday, August 4, 2004 6:07 am, Eric W. Biederman wrote:
> "Randy.Dunlap" <rddunlap@osdl.org> writes:
> > On Mon, 26 Jul 2004 15:36:05 -0700 Jesse Barnes wrote:
> > | On Monday, July 26, 2004 3:24 pm, Jesse Barnes wrote:
> > | >   o userspace tools need ia64 support
>
> Correct.  But all they need are the ia64 bits of the ELF loader,
> plus ia64 specific goo.  The generic part of the ELF loader is already
> written.

I think Khalid might already have these bits done.

> Sort of fundamentally they are arch dependent.
>
> I believe that DMA FIXME is a red hearing.  Initially that patch
> was targeted for a kernel without device_shutdown(), so I was
> likely considering the old trick of running through all of the PCI
> devices and disabling their bus master bit.

Yeah, I added that bit to remind me to think about it.

> 1) What is the kernel's argument passing format, what arguments

Right, and that should be pretty straightforward.

> 2) The code itself in machine_kexec.c and relocate_kernel.S needs
>    to place the machine in a state where virtual and physical addresses
>    are identity mapped.  And the arch specific registers are in some
>    well defined state.  Usually the least setup you can guarantee to make
>    it work the better.
>
> (This is the kernel side)
>
> We should probably start capturing these pieces of information in
> a kexec.3 man page.  Volunteers?
>
> For ia64 in particular I believe the binary arguments are the
> FPSWA and EFI memory map, and the firmware entry points (PAL and SAL
> and EFI).

With the addition of some ACPI tables and such.  I don't think those are freed 
by the kernel right now though, so it should be pretty easy to point at the 
originals from the newly kexec'd kernel, or make copies.

Jesse