[OLPC-devel] Kexec limitations?

[Marcelo Tosatti]

Hi Eric,

On Sun, Jul 09, 2006 at 05:33:52PM -0600, Eric W. Biederman wrote:
> 
> So skimming the threads I have heard two problem reports
> with using kexec at the moment.
> 1) The general purpose kexec binary is big (about 128KB)
> 2) With large kernel images (kernel+initramfs) kexec is failing.

The symptom is fixed by changing the initrd load address from
0x800000 (8MiB) to 0x1000000 (16MiB).

Newer kexec-tools already load at 16MiB, but buildrom is using 
1.97 for size reasons:

bzImage_load()
{
...

//              segment[2].mem = (void *)0x800000; /* 8MB */
                segment[2].mem = (void *)0x1000000; /* 16MB */
...
}

Not exactly sure what is happening, but probably the 8-16MiB region is
being overwritten by the kernel during early startup?

> 3) The crystal lan driver has sometimes has problems.

What crystal lan driver?

> Are those the only limitations people are aware of with kexec
> right now?

So far, yes :)

> I expect I will find a little bit of time to hack on kexec shortly
> and if I can address these issues I will.

Thanks!