From: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
To: Rich Felker <dalias@libc.org>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: 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>,
Florian Weimer <fweimer@redhat.com>,
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: Fri, 14 Dec 2018 15:13:10 +0100 [thread overview]
Message-ID: <c8987b31-ed79-acef-a300-31ebf2c29d2e@petrovitsch.priv.at> (raw)
In-Reply-To: <20181213160242.GV23599@brightrain.aerifal.cx>
[-- Attachment #1: Type: text/plain, Size: 2564 bytes --]
On 13/12/2018 17:02, Rich Felker wrote:
> On Tue, Dec 11, 2018 at 11:29:14AM +0100, John Paul Adrian Glaubitz wrote:
>> I can't say anything about the syscall interface. However, what I do know
>> is that the weird combination of a 32-bit userland with a 64-bit kernel
>> interface is sometimes causing issues. For example, application code usually
>> expects things like time_t to be 32-bit on a 32-bit system. However, this
IMHO this just historically grown (as in "it has been forever that way"
- it sounds way better in Viennese dialect though;-).
>> isn't the case for x32 which is why code fails to build.
>
> I don't see any basis for this claim about expecting time_t to be
> 32-bit. I've encountered some programs that "implicitly assume" this
> by virtue of assuming they can cast time_t to long to print it, or
> similar. IIRC this was an issue in busybox at one point; I'm not sure
> if it's been fixed. But any software that runs on non-Linux unices has
> long been corrected. If not, 2038 is sufficiently close that catching
> and correcting any such remaining bugs is more useful than covering
> them up and making the broken code work as expected.
Yup, unconditionally providing 64bit
time_t/timespec/timeval/...-equivalents with libc and syscall support
also for 32bit architectures (and deprecating all 32bit versions) should
be the way to go.
FWIW I have
---- snip ----
#if defined __x86_64__
# if defined __ILP32__ // x32
# define PRI_time_t "lld" // for time_t
# define PRI_nsec_t "lld" // for tv_nsec in struct timespec
# else // x86_64
# define PRI_time_t "ld" // for time_t
# define PRI_nsec_t "ld" // for tv_nsec in struct timespec
# endif
#else // i[3-6]68
# define PRI_time_t "ld" // for time_t
# define PRI_nsec_t "ld" // for tv_nsec in struct timespec
#endif
---- snip ----
in my userspace code for printf() and friends - I don't know how libc's
react to such a patch (and I don't care for the name of the macros as
long it's obviously clear for which type they are).
I assume/fear we won't get additional modifiers into the relevant
standards for libc types (as they are far more like pid_t, uid_t etc.).
And casting to u/intmaxptr_t to get a defined printf()-modifier doesn't
look appealing to me to "solve" such issues.
MfG,
Bernd
--
"I dislike type abstraction if it has no real reason. And saving
on typing is not a good reason - if your typing speed is the main
issue when you're coding, you're doing something seriously wrong."
- Linus Torvalds
[-- Attachment #2: pEpkey.asc --]
[-- Type: application/pgp-keys, Size: 2513 bytes --]
next prev parent reply other threads:[~2018-12-14 14:15 UTC|newest]
Thread overview: 78+ 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 9:37 ` Sven Hartrumpf
2018-12-13 9:57 ` Adam Borowski
2018-12-13 18:50 ` Sven Hartrumpf
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 [this message]
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
2019-01-22 13:34 ` Enrico Weigelt, metux IT consult
2018-12-11 20:38 Shawn Rutledge
2018-12-12 0:00 ` Maciej W. Rozycki
2018-12-12 9:12 Steven Newbury
2018-12-12 10:48 ` Thorsten Glaser
2018-12-12 13:27 ` Steven Newbury
2018-12-12 14:01 ` Rich Felker
2018-12-12 14:46 ` Steven Newbury
2018-12-12 16:05 ` Rich Felker
2018-12-13 16:17 tedheadster
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c8987b31-ed79-acef-a300-31ebf2c29d2e@petrovitsch.priv.at \
--to=bernd@petrovitsch.priv.at \
--cc=arnd@arndb.de \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dalias@libc.org \
--cc=fweimer@redhat.com \
--cc=glaubitz@physik.fu-berlin.de \
--cc=hjl.tools@gmail.com \
--cc=hpa@zytor.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=peterz@infradead.org \
--cc=torvalds@linux-foundation.org \
--cc=vapier@gentoo.org \
--cc=will.deacon@arm.com \
--cc=x32@buildd.debian.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).