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[209.85.222.175]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4a72a4e7ecdsm16034361cf.66.2025.06.13.05.09.44 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Jun 2025 05:09:44 -0700 (PDT) Received: by mail-qk1-f175.google.com with SMTP id af79cd13be357-7d38cfa9773so211321385a.2 for ; Fri, 13 Jun 2025 05:09:44 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCVK5b8BU0qDt83Ad8aVNTdR2gQlQZBMKMnKH7LDoJ68P+1Lv4KWLSpKDIWYESuBSAm/WO6TvAUINjtB@vger.kernel.org X-Received: by 2002:a05:620a:1b83:b0:7cd:1f2e:dadd with SMTP id af79cd13be357-7d3bc51e1f9mr462740685a.55.1749816583993; Fri, 13 Jun 2025 05:09:43 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-m68k@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <442267d5-241e-44a5-9b54-fee06bc5c03b@yoseli.org> <9013836044f8bfb7f0cd62ba536f6a1c75034465.camel@physik.fu-berlin.de> <80f5c684-638b-4486-9026-1f8689a7f147@yoseli.org> <95e56d983ace4976143c7e1180ffe5606c0ee3fe.camel@physik.fu-berlin.de> <758f14d8-6d03-2aab-468b-170b0bbb7d2a@linux-m68k.org> <8e0186f61cc9bbed2373ae215e80ab7e70042793.camel@physik.fu-berlin.de> <6e6f8e27ff90ce3f8535fc4f5c57049c59a9b227.camel@physik.fu-berlin.de> In-Reply-To: <6e6f8e27ff90ce3f8535fc4f5c57049c59a9b227.camel@physik.fu-berlin.de> From: Geert Uytterhoeven Date: Fri, 13 Jun 2025 14:09:31 +0200 X-Gmail-Original-Message-ID: X-Gm-Features: AX0GCFuwrpFkoqU64FGdJEPBnQSYw1XWWfuxIBb15XvQFrHKJRen_K9ZjAqkH70 Message-ID: Subject: Re: Question on BIGGEST_ALIGNMENT in GCC on NetBSD/m68k To: John Paul Adrian Glaubitz Cc: Finn Thain , Jean-Michel Hautbois , port-m68k , debian-68k , linux-m68k Content-Type: text/plain; charset="UTF-8" Hi Adrian, On Fri, 13 Jun 2025 at 14:00, John Paul Adrian Glaubitz wrote: > On Fri, 2025-06-13 at 13:55 +0200, Geert Uytterhoeven wrote: > > From its inception, Linux/m68k used an ABI compatible with SunOS, > > which dates back to the MC68000, and was probably the most popular > > UNIX OS running on m68k at that time. Several other UNIX vendors > > followed a similar path, starting from the MC68000. E.g. the HP-UX > > Portability Guide[1] states that HP-UX on HP9000/300 (based on SVR2 > > at that time, apparently) uses an alignment of 2 bytes, too. > > Linux has a strong history of not breaking the ABI between kernel and > > user space, so changing that ABI is a no-go. > Okay and how does this now fix the problems we're having on Linux/m68k? > > https://wiki.debian.org/M68k/Alignment > > We're compatible to "fails to build from source" now. I'm not sure how this > is any helpful. > > I'm not sure why several people are contributing to this discussion with > the argument that this change would break the "Linux ABI" when the Linux > ABI is currently broken and doesn't even allow for Python to be built without > further modifications. You mean Python is broken, as it makes assumptions that are not guaranteed by the C standard (oops, which one? ;-) ? ;-) Lots of older packages used to build fine on much more obscure systems than Linux/m68k. Unfortunately people stopped caring for anything not 64-bit little endian. Yes, I know saying that doesn't help... > What is your suggested alternative? Do you expect me to patch broken packages > into all eternity? If keeping 2 bytes alignment ABI is so important to so many > people, I would expect proponents to come up with solutions. > > So far, I haven't seen any. Just arguments why my approach is wrong. You are completely ignoring the last sentence I wrote... > > What you do in the layers > > above (in the kernel), or above (in userspace) is something different... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds