On Sat, Nov 17, 2007 at 07:53:25PM +0000, Evgeniy Polyakov wrote:
>
> > The second patch adds hw_random support. The ugly part is finding out
> > when to allow reads from the RNG. It currently translates the public
> > key engine clock cycles to CPU cycles based on a 4GHz CPU and uses
> > get_cycles(). The problems with this are obvious, it only works on CPUs
> > that actually have some kind of cycle counter, has problems with
> > unsynchronized TSCs and the 4GHz assumption is not very nice either,
> > but I was reluctant to use ktime for this since it seems rather
> > expensive to call ktime_get once per 4 bytes of random. Suggestion
> > for improvement of this are also welcome :)
> 
> It will not work on arm, but I'm not sure this is relevant...
> Another option is to directly access xtime without all wrappers in the
> ktime_get().

Is it really that bad? You're most likely going to be spinning
for 10us in udelay() or worse busy-looping anyway so I'm not sure
if we need to worry about that overhead too much.

Otherwise these patches look pretty nice to me.  Thanks Patrick!

Cheers,
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