[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.)

Rich.

-- 
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