[Buildroot] [PATCH v2] boot/riscv-pk: Remove obselete bootloader

[Alistair Francis]

On Mon, Oct 7, 2019 at 4:19 AM Mark Corbin <mark.corbin at embecosm.com> wrote:
>
> Hello
>
> On 28/09/2019 22:11, Thomas Petazzoni wrote:
> > On Mon, 23 Sep 2019 13:02:56 -0700
> > Alistair Francis <alistair.francis at wdc.com> wrote:
> >
> >> The RISCV Proxy Kernel (AKA BBL) isn't being used by most distros so has
> >> very limited testing. It has been replaced by OpenSBI and been
> >> deprecated for awhile, so let's just remove it.
> >>
> >> Signed-off-by: Alistair Francis <alistair.francis at wdc.com>
> >> ---
> >> v2:
> >>  - Remove package from DEVELOPERS
> >>  - Add option to Config.in.legacy
> > I'd like to have a Acked-by from Mark Corbin on this patch. Mark ?
>
> I'm in two minds about removing the BBL bootloader at the moment...
>
> ...on one hand I can see that OpenSBI should be used for all RISC-V
> projects going forward, but on the other hand there still seem to be a
> number of RISC-V projects that are using riscv-pk /BBL (and Buildroot),
> e.g. Ariane/OpenPiton, Shakti C-class and LowRISC (for Rocket core).

OpenSBI supports Ariane: https://github.com/riscv/opensbi/tree/master/platform

Although buildroot doesn't have configs for all of these platforms.

> Keeping BBL support within Buildroot at least gives people a smoother
> upgrade path, i.e. riscv-pk + Buildroot -> Buildroot (with integrated
> riscv-pk) -> Buildroot (with integrated OpenSBI).

The main problem with keeping it is that it's not maintained and as
other software keeps moving forward there will be compatibility issues
that won't be obvious to people. For example some new kernel thing
that relies on the firmware to behave in some way and BBL won't do
that. As the SBI spec is updated this will also be an issue.

>
> I know that most 'desktop' distros are moving, or are planning to move,
> to OpenSBI, but I'm not so sure about the situation for people working
> with softcores/FPGAs or more deeply embedded systems.

Most distros in general have moved on, not just the traditional
desktop distros. SiFive have moved away from it and the last real
commit to the repo was in August.

We haven't removed it from any existing buildroot releases, so anyone
who has locked into a release can continue to use it. This will just
stop new projects from starting with it and help convince people to
swap.

Alistair

>
> Thoughts?
>
> Mark
>
> --
> Mark Corbin
> Embecosm Ltd.
> https://www.embecosm.com
>
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