From: Rich Felker <dalias@libc.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: "Thomas Schöbel-Theuer" <thomas@schoebel-theuer.de>,
"Andy Lutomirski" <luto@kernel.org>, "X86 ML" <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Linux API" <linux-api@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Borislav Petkov" <bp@alien8.de>,
"Mike Frysinger" <vapier@gentoo.org>,
"H. J. Lu" <hjl.tools@gmail.com>,
x32@buildd.debian.org, "Arnd Bergmann" <arnd@arndb.de>,
"Will Deacon" <will.deacon@arm.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: Can we drop upstream Linux x32 support?
Date: Wed, 9 Jan 2019 11:02:10 -0500 [thread overview]
Message-ID: <20190109160210.GB23599@brightrain.aerifal.cx> (raw)
In-Reply-To: <871s5muhp1.fsf@oldenburg2.str.redhat.com>
On Wed, Jan 09, 2019 at 01:41:14PM +0100, Florian Weimer wrote:
> * Thomas Schöbel-Theuer:
>
> > 2) please _announce_ _now_ that after the _next_ LTS kernel (whichever
> > you want to declare as such), you will _afterwards_ drop the legacy
> > 32bit support for 64 kernels (I am deliberately using "management
> > speak" here).
> >
> > => result: the industry should have to fair chance to deal with such a
> > roadmap. Yes, it will hurt some people, but they will have enough time
> > for their migration projects.
> >
> > Example: I know that out of several millions of customers of
> > webhosting, a very low number of them have some very old legacy 32bit
> > software installed in their webspace. This cannot be supported
> > forever. But the number of such cases is very small, and there just
> > needs to be enough time for finding a solution for those few
> > customers.
> >
> > 3) the next development kernel _after_ that LTS release can then
> > immediately drop the 32bit support. Enterprise users should have
> > enough time for planning, and for lots of internal projects
> > modernizing their infrastructure. Usually, they will need to do this
> > anyway in the long term.
>
> We've already phased out support for all 32-bit architectures except
> i386 in our products, and i386 is obviously next. (We never supported
> x32 in the first place.)
>
> It becomes increasingly difficult to build a 32-bit userspace that meets
> backwards-compatibility needs. We want to use SSE2 (to avoid excess
> precision for double) and avoid relying on stack realignment (for
> compatibility with applications that use the old i386 ABI which did not
> require stack realignment). We also have to build the distribution with
> a full complement of hardening flags. This results in a combination of
> flags that is poorly tested in upstream GCC. The i386 register file
> isn't large enough to support all these features at the same time and
> combine them with function arguments passed in registers (which some
> programs enable manually via function attributes).
>
> So even if we keep the kernel interface, in the forseeable future, I
> expect that it will be difficult to build a full, contemporary 32-bit
> userspace on i386.
I guess that's informative of how one company's distro process works,
but it's not representative. Your customers are enterprise and
big-server (probably mostly the former) oriented which is exactly the
domain where 32-bit is of course irrelevant except for running legacy
applications. Where it matters are embedded and other systems striving
for resource efficiency.
For what it's worth, 32-bit archs including i386 and many others are
well-supported in Debian with no forseeable EOL I'm aware of, and most
if not all of the musl-libc-based distros I'm familiar with support
32-bit archs including i386.
I don't think waning relevance of 32-bit is a reasonable argument
against x32 since x32's relevance is in exactly the places where
32-bit is already relevant and preferred for important reasons.
Rich
next prev parent reply other threads:[~2019-01-09 16:02 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 1:23 Can we drop upstream Linux x32 support? Andy Lutomirski
2018-12-11 1:40 ` Linus Torvalds
2018-12-11 2:22 ` hpa
2018-12-11 8:16 ` Florian Weimer
2018-12-11 21:53 ` Thorsten Glaser
2018-12-11 23:22 ` Andy Lutomirski
2018-12-11 23:35 ` Thorsten Glaser
2018-12-11 23:55 ` Arnd Bergmann
2018-12-12 2:24 ` Andy Lutomirski
2018-12-12 2:33 ` Thorsten Glaser
2018-12-12 9:04 ` Arnd Bergmann
2018-12-12 18:14 ` Joseph Myers
2018-12-12 18:50 ` Ivan Ivanov
2018-12-12 19:12 ` Andy Lutomirski
2018-12-12 19:18 ` Ivan Ivanov
2018-12-12 16:39 ` Andy Lutomirski
2018-12-12 16:52 ` Rich Felker
2018-12-12 18:03 ` Andy Lutomirski
2018-12-13 12:40 ` Catalin Marinas
2018-12-13 15:57 ` Rich Felker
2018-12-13 16:04 ` Florian Weimer
2018-12-13 16:28 ` Rich Felker
2018-12-14 11:42 ` Florian Weimer
2018-12-14 16:13 ` Rich Felker
2018-12-13 18:42 ` Joseph Myers
2018-12-15 4:53 ` Thorsten Glaser
2018-12-11 23:38 ` Rich Felker
2018-12-11 23:40 ` Maciej W. Rozycki
2018-12-13 14:38 ` Olof Johansson
2018-12-13 15:46 ` Lance Richardson
2018-12-13 16:11 ` Richard Purdie
2018-12-11 3:14 ` H.J. Lu
2018-12-11 5:35 ` Andy Lutomirski
2018-12-11 9:02 ` Arnd Bergmann
2018-12-11 11:32 ` Catalin Marinas
2018-12-11 11:37 ` Florian Weimer
2018-12-11 11:52 ` Catalin Marinas
2018-12-11 5:46 ` Christian Brauner
2018-12-11 10:29 ` John Paul Adrian Glaubitz
2018-12-11 10:37 ` Florian Weimer
2018-12-11 10:44 ` John Paul Adrian Glaubitz
2018-12-11 21:59 ` Thorsten Glaser
2018-12-11 23:33 ` Rich Felker
2018-12-13 5:03 ` Kevin Easton
2018-12-13 9:05 ` Richard Weinberger
2018-12-13 12:12 ` Kevin Easton
2018-12-14 14:38 ` David Laight
2018-12-14 15:17 ` Richard Weinberger
2018-12-13 16:02 ` Rich Felker
2018-12-14 14:13 ` Bernd Petrovitsch
2018-12-14 16:17 ` Rich Felker
2018-12-14 16:29 ` Bernd Petrovitsch
2018-12-14 16:38 ` Florian Weimer
2018-12-14 16:55 ` Rich Felker
2018-12-14 18:58 ` Andy Lutomirski
2018-12-14 19:59 ` Lance Richardson
2018-12-14 20:13 ` Linus Torvalds
2018-12-14 21:27 ` Andy Lutomirski
2018-12-14 21:16 ` Thomas Schöbel-Theuer
2018-12-14 21:24 ` Andy Lutomirski
2018-12-14 21:41 ` Thomas Schöbel-Theuer
2018-12-15 7:41 ` Thomas Schoebel-Theuer
2018-12-15 15:30 ` Andy Lutomirski
2019-01-09 12:41 ` Florian Weimer
2019-01-09 16:02 ` Rich Felker [this message]
2019-01-22 13:34 ` Enrico Weigelt, metux IT consult
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