Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758113AbaDXP3F (ORCPT ); Thu, 24 Apr 2014 11:29:05 -0400 Received: from fw-tnat.austin.arm.com ([217.140.110.23]:17931 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757202AbaDXP3C (ORCPT ); Thu, 24 Apr 2014 11:29:02 -0400 Date: Thu, 24 Apr 2014 16:28:19 +0100 From: Catalin Marinas To: Chung-Lin Tang Cc: "Pinski, Andrew" , Ley Foon Tan , Arnd Bergmann , "H. Peter Anvin" , Linux-Arch , "linux-kernel@vger.kernel.org" , "linux-doc@vger.kernel.org" , Andrew Pinski , "Tang, Chung-Lin" Subject: Re: [PATCH 00/28] nios2 Linux kernel port Message-ID: <20140424152819.GI8521@arm.com> References: <1397824031-4892-1-git-send-email-lftan@altera.com> <5354AD36.5090809@zytor.com> <16597012.pEkDc99HDN@wuerfel> <5357FF8E.9010809@codesourcery.com> <5358AE96.9010006@codesourcery.com> <5358D17D.1040609@codesourcery.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5358D17D.1040609@codesourcery.com> Thread-Topic: [PATCH 00/28] nios2 Linux kernel port Accept-Language: en-GB, en-US Content-Language: en-US User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 24, 2014 at 09:55:25AM +0100, Chung-Lin Tang wrote: > On 2014/4/24 02:26 PM, Chung-Lin Tang wrote: > > On 2014/4/24 上午 02:15, Pinski, Andrew wrote: > >> > >>>> On Apr 23, 2014, at 10:59 AM, "Chung-Lin Tang" wrote: > >>>> > >>>>>> On 2014/4/22 07:20 PM, Ley Foon Tan wrote: > >>>>>> On Tue, Apr 22, 2014 at 6:56 PM, Arnd Bergmann wrote: > >>>>>>>>>> On Tuesday 22 April 2014 18:37:11 Ley Foon Tan wrote: > >>>>>>>>>>>>>> Hi Arnd and Peter Anvin, > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> Other than 64-bit time_t, clock_t and suseconds_t, can you confirm > >>>>>>>>>>>>>> that we don't need to have 64 bit off_t? See detail in link below. > >>>>>>>>>>>>>> I can submit the patches for 64-bit time changes > >>>>>>>>>>>>>> (include/asm-generic/posix_types.h and other archs) if everyone is > >>>>>>>>>>>>>> agreed on this. > >>>>>>>>>> > >>>>>>>>>> Yes. > >>>>>> Okay, will doing that. > >>>> > >>>> I believe that arm64 ILP32 will also be affected. What is the status of > >>>> this configuration? Has the glibc/kernel ABI been finalized? > >> Not yet. I am still working out the signal handling part. But we > >> already agreed on 64bit time_t, clock_t, and suseconds_t. And we > >> agreed to a 64bit offset_t too. > >> > >> On a related note suseconds in the timespec in posix is defined to > >> be long. So it would nice if the kernel ignores the upper 32bits so > >> we (glibc developers) can fix this for new targets including x32 > >> and arm64/ilp32. > > > > Hmm, but that means for purely 32-bit architectures like nios2, which > > unlike x86_64 or arm64, never has a 64-bit mode, suseconds_t as a 64-bit > > type in the kernel is simply wasted. > > The more I think of this, the more I feel that suseconds_t should jsut > be 'long', not strictly 64-bitified. An ILP32 sub-mode in a 64-bit > kernel should be using compat_* code paths, something like a > COMPAT_USE_32BIT_SUSECONDS case. ILP32 mode should use LP64 syscalls as much as possible and that's the aim with arm64 as well (of course, we still have a few that wouldn't be possible and we route them via compat). But here if time_t is 64-bit while susecconds_t is 32-bit, the compat code wouldn't help. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/