[2.4 Patch] Fix to get all sysrq-T output on iSeries virtual console

[Anton Blanchard]

> One issue with the PACA is that it is architected by the underlying system,
> so you may get bitten by using an unused byte, either because it gets used
> one day, or because there is some undefined use :-)  But you can probably
> get away with it.

Also in 2.6 it would be nice to move all fields in the paca that arent
required by the system into per cpu data. Hopefully one day we get more
intelligent and allocate per cpu data using node local memory.

There are some things that cant go into per cpu data, mainly stuff that
needs to be accessed in real mode (exception stack, rtas_args struct
etc). It would be good to clearly differentiate between stuff in the
paca that we need for the hypervisor vs stuff just there so we can get
at it in real mode.

Anton

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