[lowrisc-dev] Re: lowRISC kernel changes rebased over stock 4.19

Richard W.M. Jones rjones at redhat.com
Wed Oct 31 16:39:14 GMT 2018

On Wed, Oct 31, 2018 at 10:31:56AM -0400, Gabriel L. Somlo wrote:
> I'm trying to build the smallest CPU core that could still boot Linux
> (probably some form of rv32ima[c], maybe from Pulp), and needed to start
> with something that already works, understand it, and try to remove it
> and scale it down as far as possible. The opposite direction (start with
> a tiny core, and add things to it until it boots Linux) seemed like it
> had too many ways to go wrong, so I decided to try and scale *down*
> instead of *up* :)

You're going to have a problem running distros as soon as you drop
64-bit support.  Certainly Fedora and Debian require RV64GC.  Dropping
the C extension is also difficult as it will require recompiling
everything.  Dropping floating point is probably easier, especially if
there's a way to trap and emulate.

(Of course this only applies if you want to run the big distros, not
if you're using Buildroot or whatever.)


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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