Hitachi djprobe mechanism

[Keshavamurthy, Anil S]

>
>There are more efficient ways of implementing a jmp type hook - see the
>kernel hooks package, where we evloved past this string of 5 no-ops
>implementation Here we moved an immediate value - 1 byte - 
>into a reg and
>jumped on the reg being non-zero. To spring the hook we stored the one
>immediate byte in the mov instruction. This technique works 
>quite well on
>IA64 where one can use a predicate register for the same purpose.

Yup, I agree with you and this seems to the correct way to support
djprobe 
with having to worry about all the other issues which we have discussed
earlier. 
The only _limitations_ here is that djprobe can only be placed if there
is a static hook as mentioned above.

-thanks,
Anil