Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932811AbbKMPiw (ORCPT ); Fri, 13 Nov 2015 10:38:52 -0500 Received: from mail-lb0-f171.google.com ([209.85.217.171]:33294 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754225AbbKMPiu (ORCPT ); Fri, 13 Nov 2015 10:38:50 -0500 MIME-Version: 1.0 In-Reply-To: <3810107.ZiMyX4Iloo@wuerfel> References: <1446507046-24604-1-git-send-email-ynorov@caviumnetworks.com> <16446627.b0Lo936ZJj@wuerfel> <3810107.ZiMyX4Iloo@wuerfel> Date: Fri, 13 Nov 2015 07:38:49 -0800 Message-ID: Subject: Re: [PATCH v6 13/17] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it From: Andrew Pinski To: Arnd Bergmann Cc: Andreas Schwab , "linux-arm-kernel@lists.infradead.org" , Yury Norov , "Kapoor, Prasun" , Catalin Marinas , Nathan Lynch , LKML , Alexander Graf , Alexey Klimov , broonie@kernel.org, Jan Dakinevich , Andrew Pinski , David Daney , bamvor.zhangjian@huawei.com, Philipp Tomsich , Andrey Konovalov , christoph.muellner@theobroma-systems.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 50 On Fri, Nov 13, 2015 at 7:34 AM, Arnd Bergmann wrote: > On Thursday 12 November 2015 14:47:18 Andreas Schwab wrote: >> Arnd Bergmann writes: >> >> > On Thursday 12 November 2015 10:44:55 Andreas Schwab wrote: >> >> Arnd Bergmann writes: >> >> >> >> > What do you mean with 32-bit off_t? >> >> >> >> An ABI with 32-bit off_t, ie. all currently implemented 32-bit ABIs. >> >> >> >> > Do you mean that glibc emulates a 32-bit off_t on top of the 64-bit >> >> > __kernel_loff_t? >> >> >> >> Glibc is bridging the user-space ABI to the kernel ABI. >> > >> > Ok, but why? >> >> That's how the ABI is defined right now. I didn't make that up. > > Ok, I guess it will remain a mystery then. The biggest question is here is how much compatibility do we want with other 32bit ABIs? Do we want off_t to be 32bit or 64bit? > > Should we perhaps define __ARCH_WANT_SYSCALL_OFF_T for the unistd.h > file then, so we provide both the off_t and the loff_t based syscalls? I think that is backwards ... > > That would avoid the extra wrapper in glibc when using a 32-bit > off_t if that is the preferred mode for user space. Other targets like tilegx does not do that and has a pure 32bit mode. Only score does that. Thanks, Andrew > > Arnd -- 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/