From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 44F2C524C for ; Mon, 28 Oct 2024 07:26:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=130.133.4.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730100400; cv=none; b=XHUjUC4hqqSEkOlAB39Y8TBmFVEnWyeEYtPBeZP2pFbZ6WZekmN2LjrBxU7AwhSI3VdVCVTak/cYnwV3JW4ujLqfSnrdKYzbWaWpfK14JJcHADvEwlKtP2oL+vToEuAIqbafY7CAbcCcW+p70TMQaW1rQJrIj5kOYEwN95ebuoo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730100400; c=relaxed/simple; bh=Z8fWDDpd8Cr79qL8aUkY0jA68WNej6n8fk3MwTrAtCQ=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=b5JlNMJDeLZMBI32I9+U1ldBrm8hGBvxanM3yySs3ZnD0AtMX4nUTlX/loMc08SWjcc9d3CvLfM4SNLcIR3pKK4St/lG/RcGd529LLvfl/SigFmB9kdlBRoNLPeLxefMZEjKXww6N+E+CNyOl2HYpO65KX6fFgpPOtYfoN9uZbo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de; spf=pass smtp.mailfrom=zedat.fu-berlin.de; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b=BCVPsfLa; arc=none smtp.client-ip=130.133.4.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zedat.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b="BCVPsfLa" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fu-berlin.de; s=fub01; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=D3HdmQm/tHucu0CmcShIfpOk5+q7hq/p5pozUzmYHa4=; t=1730100397; x=1730705197; b=BCVPsfLaalJPWoVlT3RB35xBAp5IME2UL7IXR6NcRC1MzfSXhsnm/iQRlAwzGqWyDPU8zRyGC6e X8YjLDJdbElV4Dj6Ik903gQ0j2iFAx3oFvCbEpmNyzGvrmVSbZ5XaFFreMlXW7g4NM1pRAw5r37Yq Qz0gGJKABuwwhIkTDWuN0iquhheIuI3g6MGpFbyOjJoN+hUniWRIHRYy2c6JM/PZuSI949a/TK3T6 qSFtqE91J8QI5ToBVaGQohWO19iGexsA7M3Zfsr+yAFsk1OVYtsRIzmFDC0APjX2pjoQ1c5O6/wx5 +KYDbaWbsMXhhvTQKsJQ+ObKwpStAgEmJQ+w==; Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.98) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1t5K95-00000003peO-2K4t; Mon, 28 Oct 2024 08:26:35 +0100 Received: from p57bd904e.dip0.t-ipconnect.de ([87.189.144.78] helo=[192.168.178.20]) by inpost2.zedat.fu-berlin.de (Exim 4.98) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1t5K95-000000025YY-1Pag; Mon, 28 Oct 2024 08:26:35 +0100 Message-ID: Subject: Re: Plan needed for switching m68k to 32-bit alignment From: John Paul Adrian Glaubitz To: Thorsten Glaser Cc: Arnd Bergmann , linux-m68k , debian-68k , James Le Cuirot , Sam James , Geert Uytterhoeven , Andreas Schwab Date: Mon, 28 Oct 2024 08:26:34 +0100 In-Reply-To: <97b0a5de-885f-ffde-3739-f7f29b16d3bd@mirbsd.de> References: <3a5e171bf42e5273eb8235cba04e8328b19c2ca4.camel@physik.fu-berlin.de> <383faec7-8987-4680-920d-8f802e1bea34@app.fastmail.com> <97b0a5de-885f-ffde-3739-f7f29b16d3bd@mirbsd.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.1 Precedence: bulk X-Mailing-List: linux-m68k@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-ZEDAT-Hint: PO On Fri, 2024-10-25 at 23:38 +0200, Thorsten Glaser wrote: > On Fri, 25 Oct 2024, John Paul Adrian Glaubitz wrote: >=20 > > as m68k has supported 32-bit alignment through the "-malign-int" > > switch for a long time. >=20 > That switch constitutes a fundamental ABI change, even if > the effect is limited. >=20 > Question is, do we need a kernel change for this at all? > Is there anything in the kernel/userland interface that > gets affected by this, or do these APIs use sufficient > explicit padding? Has anyone looked at this? James Le Cuirot (chewi) has created a Gentoo/m68k chroot with 4-byte alignment and most of the stuff just worked from what I remember. > If we know that the answer is no, the plan could look > different from a yes answer, so=E2=80=A6 >=20 > Additionally=E2=80=A6 has anyone done the simple =E2=80=9Cenable -malign-= int > in GCC, begin rebuilding stuff, first glibc, then others, > see what breaks=E2=80=9D? Is there sufficient effect that we cannot > incrementally change over? Yes, see above. > (Another question: does -malign-int switch to natural > alignment for all types, i.e. 64 bit for llong and double, > etc. or are we going to have to change GCC first as well > to avoid more surprises?) I assume so. Chewi, can you answer that question? Adrian --=20 .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913