[IA64] [Xen-ia64-devel] Add ptc.l emulation for 2.6.17 xenlinux to fix federon-xen-ia64 boot

[Zhang, Xiantao]

This patch adds support for ptc.l emulation. In 2.6.16 kernel
flush_tlb_range will call global_tlb_purge directly, so ptc.l shouldn't
be used when CONFIG_SMP enable.
But in order to enhance performance (maybe), 2.6.17 kernel in smp
environment will do mm check first. If mm is current->active_mm and the
mm
(corresponding process) just runs on the local processor, kernel only
needs to do ptc.l at local processor instead of global purge. So ptc.l
emulation is necessary for 2.6.17 kernel.

Hi Aron, 
With this patch, federon-xen-ia64 with rhel4-u2 can boot to "switch to
new root". Seems this error is related to FC6 OS, maybe initrd has
something wrong  in rhel4-u2. Due to lack of FC6 at hand, we couldn't
try to boot it on FC6. Anyway, this patch is a must for boot 2.6.17
kernel.
In addition, I attached the boot log, anyone can help to try on FC6 with
this patch? 

Thanks
-Xiantao

[Aron Griffis]

Zhang, Xiantao wrote: [Wed May 24 2006, 09:47:54AM EDT]
>  Hi Aron,  
Hi Xiantao,

>  With this patch, federon-xen-ia64 with rhel4-u2 can boot to
> "switch to
>  new root". Seems this error is related to FC6 OS, maybe initrd has
>  something wrong  in rhel4-u2. Due to lack of FC6 at hand, we couldn't
>  try to boot it on FC6. Anyway, this patch is a must for boot 2.6.17
>  kernel.
>  In addition, I attached the boot log, anyone can help to try on FC6 with
>  this patch?  
Thanks you for this patch!  Alex applied it to xen-ia64-unstable
earlier today, and following that I updated my rpm with the new
changeset.

I am seeing the exact same issue that you reported (/dev/root mounting
problems) on fedora rawhide.  I will let you know if I can debug it.

Regards,
Aron