From nobody Mon Feb 9 15:56:37 2026 X-Original-To: dev-commits-src-all@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 4f8q7f3YfBz6RdKh; Mon, 09 Feb 2026 15:56:46 +0000 (UTC) (envelope-from minsoochoo0122@proton.me) Received: from mail-10631.protonmail.ch (mail-10631.protonmail.ch [79.135.106.31]) (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 (4096 bits) client-digest SHA256) (Client CN "protonmail.com", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4f8q7d4KF2z3GNF; Mon, 09 Feb 2026 15:56:45 +0000 (UTC) (envelope-from minsoochoo0122@proton.me) Authentication-Results: mx1.freebsd.org; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=ze6rz3zcsng5bnhollvfzp75le.protonmail; t=1770652602; x=1770911802; bh=RIgf1FX5jWjeNscKadlF7n5om7C3is1VpjlGBItdH4k=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=XmmvL/44jLCzhQp0DbMQVOQh1eatc/q9Ywvn5NhF8PeVy3eKc26ElWg9Ewg+ploOL xQMSELdkTeDs4Y/9GJ6tbXhDGAAPmknXxXqOJqPItT7GelVA/B2yD+NphoUn5WP4PM q5CBJ3HErCYgy1IIfOMjAcsoxRI2PM7p+e9Y4U+4I+5dQjkUUJPm8ea0atnYN8Oj5l uu9HAgu8f5586dP2nw7huPb/exY7n3MKuKhebHd0lUQiT/hNFUQ7goFjGbulB/MJwx jLc9xliNe9UWx8tsU6lWDe9O3gDqhg9uR5+C5KyjGa/rrGTfKWcypInTWLLhxRBZ7r uZBvMyv77SpcQ== Date: Mon, 09 Feb 2026 15:56:37 +0000 To: John Baldwin From: Minsoo Choo Cc: Konstantin Belousov , src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: 8f23665fed2f - main - pcb.h: mark struct pcb to be preserved Message-ID: In-Reply-To: <5bec84ad-a01e-4931-98e6-4ba06adb1237@FreeBSD.org> References: <69896027.2112e.2852c0dd@gitrepo.freebsd.org> <5bec84ad-a01e-4931-98e6-4ba06adb1237@FreeBSD.org> Feedback-ID: 45891198:user:proton X-Pm-Message-ID: d66f7c3c19672ba3585ddb4e085d2abd5156a13f List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:62371, ipnet:79.135.106.0/24, country:CH] X-Rspamd-Queue-Id: 4f8q7d4KF2z3GNF X-Spamd-Bar: ---- On Monday, February 9th, 2026 at 10:12 AM, John Baldwin w= rote: > On 2/8/26 23:18, Konstantin Belousov wrote: >=20 > > The branch main has been updated by kib: > >=20 > > URL: https://cgit.FreeBSD.org/src/commit/?id=3D8f23665fed2fbaf4481359b4= d2fcdd7b9feb40e3 > >=20 > > commit 8f23665fed2fbaf4481359b4d2fcdd7b9feb40e3 > > Author: Minsoo Choo minsoochoo0122@proton.me > > AuthorDate: 2026-02-06 20:03:53 +0000 > > Commit: Konstantin Belousov kib@FreeBSD.org > > CommitDate: 2026-02-09 04:17:16 +0000 > >=20 > > pcb.h: mark struct pcb to be preserved > >=20 > > There are programs that depend on this structure (e.g. kernel debuggers= ) > > that breaks when the ABI changes. > >=20 > > Signed-off-by: Minsoo Choo minsoochoo0122@proton.me > > Reviewed by: kib > > MFC after: 1 week > > Differential Revision: https://reviews.freebsd.org/D55149 >=20 >=20 > Hmmm, I think it is useful to know which fields debuggers use (typically = just > registers) vs which ones can be safely changed without impacting debugger= s. >=20 > -- > John Baldwin In the review, kib said: > I had to add and preserve the padding fields pcb_pad in the amd64 structu= re to be compatible with kgdb at least. This makes me sure that the whole p= cb layout is fixed by ABI. I can create a patch to mark fields that are used by kernel debuggers. pcb = and trapframe aren't usually used by userland programs, but we have excepti= on for kernel debuggers here. We should have consensus on whether the whole= structure should be stable ABI or not. My preference is that if any of the architectures (e.g. amd64) need the who= le pcb structure to be stable, then we should do the same to the others as = well to avoid confusion.