From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chung-Lin Tang Subject: Re: [PATCH 00/28] nios2 Linux kernel port Date: Thu, 24 Apr 2014 16:55:25 +0800 Message-ID: <5358D17D.1040609@codesourcery.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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <5358AE96.9010006@codesourcery.com> Sender: linux-doc-owner@vger.kernel.org To: "Pinski, Andrew" Cc: Ley Foon Tan , Arnd Bergmann , "H. Peter Anvin" , Linux-Arch , "linux-kernel@vger.kernel.org" , "linux-doc@vger.kernel.org" , "Catalin.Marinas@arm.com" , Andrew Pinski , "Tang, Chung-Lin" List-Id: linux-arch.vger.kernel.org On 2014/4/24 02:26 PM, Chung-Lin Tang wrote: > On 2014/4/24 =E4=B8=8A=E5=8D=88 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 w= rote: >>>>>>>>>> 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 y= ou confirm >>>>>>>>>>>>>> that we don't need to have 64 bit off_t? See detail in l= ink below. >>>>>>>>>>>>>> I can submit the patches for 64-bit time changes >>>>>>>>>>>>>> (include/asm-generic/posix_types.h and other archs) if e= veryone is >>>>>>>>>>>>>> agreed on this. >>>>>>>>>> >>>>>>>>>> Yes. >>>>>> Okay, will doing that. >>>> >>>> I believe that arm64 ILP32 will also be affected. What is the stat= us of >>>> this configuration? Has the glibc/kernel ABI been finalized? >> Not yet. I am still working out the signal handling part. But we al= ready agreed on 64bit time_t, clock_t, and suseconds_t. And we agreed = to a 64bit offset_t too.=20 >> >> On a related note suseconds in the timespec in posix is defined to b= e 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.=20 >=20 > 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. >=20 > Chung-Lin 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. suseconds_t is for micro-seconds in struct timeval, 32-bit is more than enough. Chung-Lin