From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Weinberger Subject: Re: Can we drop upstream Linux x32 support? Date: Fri, 14 Dec 2018 16:17:59 +0100 Message-ID: <3143388.E8mgBzaflP@blindfold> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: David Laight Cc: 'Richard Weinberger' , "kevin@guarana.org" , "glaubitz@physik.fu-berlin.de" , Andy Lutomirski , "x86@kernel.org" , LKML , "open list:ABI/API" , "H. Peter Anvin" , Peter Zijlstra , Borislav Petkov , "fweimer@redhat.com" , Mike Frysinger , "H.J. Lu" , "dalias@libc.org" , "x32@buildd.debian.org" , Arnd Bergmann , Will Deacon , Catalin Marinas , Linus Torvalds List-Id: linux-api@vger.kernel.org Am Freitag, 14. Dezember 2018, 15:38:53 CET schrieb David Laight: > From: Richard Weinberger > > Sent: 13 December 2018 09:05 > > On Thu, Dec 13, 2018 at 6:03 AM Kevin Easton 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. > > Not true at all. > The binary compatibility in NetBSD is probably better than that in Linux > and goes back a long way. > > For the time_t changes new system calls numbers were assigned where needed. > The system headers and libc were updated so that recompiled code would > use the new system calls. > > The only real advantage that NetBSD has is that its libc (and standard > utilities) are released with the kernel making it much easier to get > applications to use the new features. > > This was also done a very long time ago when file offsets were extended > to 64 bits. > > Some of the system calls have quite a few 'compatibility' versions. > As well as the ones for emulations of other operating systems. > It has been possible to run copies of firefox compiled for Linux > under NetBSD. I stand corrected, I was under the impression that NetBSD went the same path as OpenBSD did. Thanks for pointing this out. Thanks, //richard