Date: Mon, 10 Jan 2022 22:37:11 +0100 From: Olivier Houchard <cognet@ci0.org> To: Warner Losh <imp@bsdimp.com> Cc: John Baldwin <jhb@freebsd.org>, Warner Losh <imp@freebsd.org>, src-committers <src-committers@freebsd.org>, "<dev-commits-src-all@freebsd.org>" <dev-commits-src-all@freebsd.org>, dev-commits-src-main@freebsd.org Subject: Re: git: d6c0538dae8d - main - ddb: Remove SOFTWARE_SSTEP support Message-ID: <YdynB3Omo4RK16Fx@ci0.org> In-Reply-To: <CANCZdfq0UCZvdcsuaWx3KXqrKBBYoxDHqc=_P3U7L4QpCyh=rw@mail.gmail.com> References: <202201071627.207GRsGX062055@gitrepo.freebsd.org> <45275428-75e2-aaae-bed3-e5e84b39e17c@FreeBSD.org> <CANCZdfq0UCZvdcsuaWx3KXqrKBBYoxDHqc=_P3U7L4QpCyh=rw@mail.gmail.com>
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On Mon, Jan 10, 2022 at 02:14:54PM -0700, Warner Losh wrote: > 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? > It was used for arm, but only older arm, ie v4/v5, pretty sure newer cores do have hardware breakpoints. Regards, Olivier
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