Re: git: d6c0538dae8d - main - ddb: Remove SOFTWARE_SSTEP support

From: Warner Losh <imp_at_bsdimp.com>
Date: Mon, 10 Jan 2022 21:14:54 UTC 
On Mon, Jan 10, 2022 at 12:48 PM John Baldwin <jhb@freebsd.org> wrote:

> On 1/7/22 8:27 AM, Warner Losh wrote:
> > The branch main has been updated by imp:
> >
> > URL:
> https://cgit.FreeBSD.org/src/commit/?id=d6c0538dae8d138219dfd051994a44c50e741212
> >
> > commit d6c0538dae8d138219dfd051994a44c50e741212
> > Author:     Warner Losh <imp@FreeBSD.org>
> > AuthorDate: 2022-01-07 16:25:33 +0000
> > Commit:     Warner Losh <imp@FreeBSD.org>
> > CommitDate: 2022-01-07 16:25:33 +0000
> >
> >      ddb: Remove SOFTWARE_SSTEP support
> >
> >      It was needed for mips only, and only kinda sorta worked for mips.
> It
> >      can be brought back if we grow another architecture that need it.
> >
> >      Sponsored by:           Netflix
>
> RISC-V would need it in theory (no hardware single step), but no one has
> felt the
> need to implement the backend support for it.  I think 32-bit arm doesn't
> support
> hardware single step either (but again, no one has bothered to add the
> backend
> support).
>

Generally, I agree with these thoughts. I went ahead with the removal
because I
knew it would be easy to bring back, even years from now should someone[tm]
have an implementation for those platforms (though I thought 32-bit arm did
have
single step in hardware).

Should I put it back? Or should we wait until someone shows up with support
for
a supported platform?

Warner