Hitachi djprobe mechanism

[Keshavamurthy, Anil S]

>In as far as I can see, it remains that the only safe way to 
>use djprobe
>is to not touch any instruction that is less than 5 bytes, that's if
>there aren't other limitations as I mentioned earlier.

Though this is the safe way to insert djprobe, this might not always
serve the desired purpose.

Say for example, user is interested to find how many times a function
gets called and he need 
to insert a probe at the beginning of a function. Due to the nature of
djprobe
1) we might not find a 5 byte instruction with in this function, Or
2) Even if we find one such instruction, that instruction might tend to 
not get executed (due to nature of the code flow), then in this case
If user inserts a probe looking at 5 bytes or more instruction from the
beginning 
of the function address, the results (i.e times a function entered) will
end up being wrong.

So in effect, we just can't look for instruction size greater than 5
bytes and insert probe there. 
This djprobe will push the need for a stronger static
analysizer/translator in selecting the probe point.

-thanks,
Anil