Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <CALCETrXoRAibsbWa9nfbDrt0iEuebMnCMhSFg-d9W-J2g8mDjw@mail.gmail.com>
 <70bb54b2-8ed3-b5ee-c02d-6ef66c4f27eb@physik.fu-berlin.de> <20181213050313.GA21201@ip-172-31-15-78>
In-Reply-To: <20181213050313.GA21201@ip-172-31-15-78>
From:   Richard Weinberger <richard.weinberger@gmail.com>
Date:   Thu, 13 Dec 2018 10:05:14 +0100
Message-ID: <CAFLxGvy2sMW1nyMpxGN7xHPdUea713g89MdE3EcUNHJDCvZ3jA@mail.gmail.com>
Subject: Re: Can we drop upstream Linux x32 support?
To:     kevin@guarana.org
Cc:     glaubitz@physik.fu-berlin.de, Andy Lutomirski <luto@kernel.org>,
        x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
        "open list:ABI/API" <linux-api@vger.kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>, fweimer@redhat.com,
        Mike Frysinger <vapier@gentoo.org>,
        "H.J. Lu" <hjl.tools@gmail.com>, dalias@libc.org,
        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>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Dec 13, 2018 at 6:03 AM Kevin Easton <kevin@guarana.org> 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
> > isn't the case for x32 which is why code fails to build.
>
> OpenBSD and NetBSD both have 64-bit time_t on 32-bit systems and have
> had for four or five years at this point.

They can also do flag-day changes and break existing applications, Linux not.

-- 
Thanks,
//richard