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Date: Sat, 19 Jun 2021 09:36:40 -0500
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH v2 6/9] powerpc/microwatt: Add support for hardware random
 number generator
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On Sat, Jun 19, 2021 at 01:08:51PM +1000, Nicholas Piggin wrote:
> Excerpts from Paul Mackerras's message of June 18, 2021 1:47 pm:
> > Microwatt's hardware RNG is accessed using the DARN instruction.
> 
> I think we're getting a platforms/book3s soon with the VAS patches, 
> might be a place to add the get_random_darn function.
> 
> Huh, DARN is unprivileged right?

It is, that's the whole point: to make it very very cheap for user
software it has to be an unprivileged instruction.


Segher