From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/7003 Path: news.gmane.org!not-for-mail From: Catalin Marinas Newsgroups: gmane.linux.kernel,gmane.comp.lib.glibc.alpha,gmane.linux.lib.musl.general,gmane.linux.ports.arm.kernel Subject: Re: [PATCHv3 00/24] ILP32 support in ARM64 Date: Thu, 12 Feb 2015 15:50:24 +0000 Message-ID: <20150212155023.GA25491@e104818-lin.cambridge.arm.com> References: <20141002155217.GH32147@e104818-lin.cambridge.arm.com> <20150210181302.GA23886@brightrain.aerifal.cx> <20150211190252.GB23507@brightrain.aerifal.cx> <20150211192558.GE23507@brightrain.aerifal.cx> <20150211194741.GI23507@brightrain.aerifal.cx> <54DBB87C.5060901@amacapital.net> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1423756250 20101 80.91.229.3 (12 Feb 2015 15:50:50 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 12 Feb 2015 15:50:50 +0000 (UTC) Cc: "H.J. Lu" , Rich Felker , GNU C Library , Andrew Pinski , musl@lists.openwall.com, LKML , Andrew Pinski , "linux-arm-kernel@lists.infradead.org" To: Andy Lutomirski Original-X-From: linux-kernel-owner@vger.kernel.org Thu Feb 12 16:50:42 2015 Return-path: Envelope-to: glk-linux-kernel-3@plane.gmane.org Original-Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YLw2K-0008OL-QM for glk-linux-kernel-3@plane.gmane.org; Thu, 12 Feb 2015 16:50:41 +0100 Original-Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756096AbbBLPug (ORCPT ); Thu, 12 Feb 2015 10:50:36 -0500 Original-Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:43434 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753150AbbBLPue (ORCPT ); Thu, 12 Feb 2015 10:50:34 -0500 Original-Received: from foss-smtp-na-1.foss.arm.com (unknown [10.80.61.8]) by foss-mx-na.foss.arm.com (Postfix) with ESMTP id 89CC24E4; Thu, 12 Feb 2015 09:50:30 -0600 (CST) Original-Received: from collaborate-mta1.arm.com (highbank-bc01-b06.austin.arm.com [10.112.81.134]) by foss-smtp-na-1.foss.arm.com (Postfix) with ESMTP id 0AA0F5FAC1; Thu, 12 Feb 2015 09:50:28 -0600 (CST) Original-Received: from e104818-lin.cambridge.arm.com (e104818-lin.cambridge.arm.com [10.1.203.148]) by collaborate-mta1.arm.com (Postfix) with ESMTPS id 74E0513F638; Thu, 12 Feb 2015 09:50:26 -0600 (CST) Content-Disposition: inline In-Reply-To: <54DBB87C.5060901@amacapital.net> User-Agent: Mutt/1.5.23 (2014-03-12) Original-Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Xref: news.gmane.org gmane.linux.kernel:1887365 gmane.comp.lib.glibc.alpha:49213 gmane.linux.lib.musl.general:7003 gmane.linux.ports.arm.kernel:393094 Archived-At: On Wed, Feb 11, 2015 at 12:15:56PM -0800, Andy Lutomirski wrote: > On 02/11/2015 11:57 AM, H.J. Lu wrote: > >>>>trivially satisfied if you consider x32 and x86_64 separate > >>>>compilation environments, but it's not related to the core issue: that > >>>>the definition of timespec violates core (not obscure) requirements of > >>>>both POSIX and C11. At the time you were probably unaware of the C11 > >>>>requirement. Note that it's a LOT harder to effect change in the C > >>>>standard, so even if the Austin Group would be amenable to changing > >>>>the requirement for timespec to allow something like nseconds_t, > >>>>getting WG14 to make this change to work around a Linux/glibc mistake > >>>>does not sound practical. > >>> > >>>That is very unfortunate. I consider it is too late for x32 to change. > >> > >>Why? It's hardly an incompatible ABI change, as long as the > >>kernel/libc fills the upper bits (for old programs that read them > >>based on the old headers) when structs are read from the kernel to the > >>application, and ignores the upper bits (potentially set or left > >>uninitialized by the application) when strings are passed from > >>userspace to the kernel. Newly built apps using the struct definition > >>with 32-bit tv_nsec would need new libc to ensure that the high bits > >>aren't interpreted, but this could be handled by symbol versioning. > >> > > > >We have considered this option. But since kernel wouldn't change > >tv_nsec/tv_usec handling just for x32, it wasn't selected. > > Did anyone *ask* the kernel people (e.g. hpa)? It seems so: https://lkml.org/lkml/2011/8/31/244 Couple of more replies from hpa: https://lkml.org/lkml/2011/8/31/261 https://lkml.org/lkml/2012/2/8/408 It looks like hpa was going to talk the POSIX committee but I don't know what the conclusion was and didn't follow the thread (at the time I wasn't interested in ARM ILP32). -- Catalin