[patch] ia64: make PA() work for both physical identity-mapped virtual addresses

[Simon Horman]

On Mon, Oct 06, 2008 at 09:24:03AM -0600, Bjorn Helgaas wrote:
> The EFI Runtime Services Table contains pointers to ia64 function
> descriptors.  On existing, pre-Tiano, firmware, SetVirtualAddressMap()
> converts *all* these pointers from physical to virtual.  On Tiano-based
> firmware, the pointer to the SetVirtualAddressMap() function descriptor
> is not converted, so it remains a physical pointer.
> 
> The ia64 kexec purgatory patches the SetVirtualAddressMap() function
> descriptor so that when the new kernel calls SetVirtualAddressMap(), it
> never reaches firmware.  Instead, it calls a dummy function that just
> returns success.
> 
> Purgatory runs in physical mode, so it must convert the pointer from the
> RuntimeServicesTable to a physical address.  This patch makes that
> conversion work both for old firmware (where the pointer is an identity-
> mapped virtual address) and new Tiano firmware (where the pointer is a
> physical address).
> 
> Without this patch, kexec on Tiano firmware causes an MCA because
> ia64_env_setup() subtracts PAGE_OFFSET from a physical address and ends
> up with an invalid physical address.  Referencing that address causes
> the MCA.
> 
> Signed-off-by: Bjorn Helgaas <bjorn.helgaas at hp.com>

Thanks Bjorn, applied.

-- 
Simon Horman
  VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
  H: www.vergenet.net/~horms/             W: www.valinux.co.jp/en