From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9048 invoked by alias); 8 Jun 2012 14:49:29 -0000 Received: (qmail 9011 invoked by uid 22791); 8 Jun 2012 14:49:24 -0000 X-SWARE-Spam-Status: No, hits=-4.9 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,KHOP_RCVD_TRUST,KHOP_THREADED,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE,TW_HW X-Spam-Check-By: sourceware.org Received: from mail-gg0-f169.google.com (HELO mail-gg0-f169.google.com) (209.85.161.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 08 Jun 2012 14:49:11 +0000 Received: by ggm4 with SMTP id 4so1539137ggm.0 for ; Fri, 08 Jun 2012 07:49:10 -0700 (PDT) Received: by 10.236.73.39 with SMTP id u27mr7648841yhd.40.1339166950882; Fri, 08 Jun 2012 07:49:10 -0700 (PDT) Received: from pebble.twiddle.home ([173.160.232.49]) by mx.google.com with ESMTPS id j34sm9632913ani.14.2012.06.08.07.49.09 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 08 Jun 2012 07:49:10 -0700 (PDT) Message-ID: <4FD210E2.5010006@twiddle.net> Date: Fri, 08 Jun 2012 14:49:00 -0000 From: Richard Henderson User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Andreas Krebbel CC: "Ryan S. Arnold" , libc-alpha@sourceware.org, libc-ports@sourceware.org Subject: Re: Include hwcap as ifunc argument References: <4FBA744A.6000702@twiddle.net> <4FBFC4EC.1060209@twiddle.net> <4FCD333E.3090107@twiddle.net> <4FD2056E.3060704@linux.vnet.ibm.com> In-Reply-To: <4FD2056E.3060704@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact libc-ports-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: libc-ports-owner@sourceware.org X-SW-Source: 2012-06/txt/msg00020.txt.bz2 On 2012-06-08 07:00, Andreas Krebbel wrote: >>From a S/390 perspective AT_PLATFORM would also be more helpful. We do not add every new > machine feature to the hwcaps vector so it is not possible to deduce the cpu level just > from the hwcaps vector. No, but the one important thing in s390's AT_HWCAP is HWCAP_S390_STFLE, which tells you (without setting up sigill handlers) that you can go ahead and find out *everything* you want to know via stfle. More or less exactly how the x86 port works atm with its cpuid bits. But again, it depends on what you're trying to test. Are you looking at choosing a version based on scheduling, or choosing a version based on features? I'd would hope that any multiarch'd version of e.g. feraiseexcept would test for the ieee-exception-simulation-facility (included in bit 41 of stfle results) rather than using a strcmp of AT_PLATFORM vs "z109-xx" (or whatever). Certainly for libatomic I would be most interested in testing for the presence of the interlocked-access and compare-and-swap-and-store-2 facilities. > I'm working on the S/390 ifunc support and hope to be able to come up with a patch soon. Excellent. r~