From nobody Mon Jan 10 21:37:11 2022 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 19805194DD0E; Mon, 10 Jan 2022 21:37:58 +0000 (UTC) (envelope-from cognet@ci0.org) Received: from kanar.ci0.org (kanar.ci0.org [IPv6:2001:bc8:35e6::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "sd-143795", Issuer "sd-143795" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JXnHT682Wz4Zxh; Mon, 10 Jan 2022 21:37:57 +0000 (UTC) (envelope-from cognet@ci0.org) Received: from kanar.ci0.org (localhost [127.0.0.1]) by kanar.ci0.org (8.16.1/8.16.1) with ESMTPS id 20ALbDgI074776 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 10 Jan 2022 22:37:13 +0100 (CET) (envelope-from cognet@ci0.org) Received: (from doginou@localhost) by kanar.ci0.org (8.16.1/8.16.1/Submit) id 20ALbBYv074775; Mon, 10 Jan 2022 22:37:11 +0100 (CET) (envelope-from cognet@ci0.org) X-Authentication-Warning: kanar.ci0.org: doginou set sender to cognet@ci0.org using -f Date: Mon, 10 Jan 2022 22:37:11 +0100 From: Olivier Houchard To: Warner Losh Cc: John Baldwin , Warner Losh , src-committers , "" , dev-commits-src-main@freebsd.org Subject: Re: git: d6c0538dae8d - main - ddb: Remove SOFTWARE_SSTEP support Message-ID: References: <202201071627.207GRsGX062055@gitrepo.freebsd.org> <45275428-75e2-aaae-bed3-e5e84b39e17c@FreeBSD.org> List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-main@freebsd.org X-BeenThere: dev-commits-src-main@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 4JXnHT682Wz4Zxh X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-ThisMailContainsUnwantedMimeParts: N On Mon, Jan 10, 2022 at 02:14:54PM -0700, Warner Losh wrote: > On Mon, Jan 10, 2022 at 12:48 PM John Baldwin 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 > > > AuthorDate: 2022-01-07 16:25:33 +0000 > > > Commit: Warner Losh > > > 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