From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id A60401F461 for ; Thu, 18 Jul 2019 20:32:00 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:to:cc:references:from:subject:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; q=dns; s=default; b=RSZ+axLm80dssDh3 SbAG/lorHLbN0k/CP+WC9Cpx/+PHymKDBgD24BJ+zBxwAGuZz6b0i1pMi6B+/Gme 4v7GO8QIokTYGgL8AC6DvWDVKS4mr73dUDp/9ZbpkcefDQnlsestkvQadkhOlKUJ 2kva2+PFZ4ySOmU5DgOty34Bs8U= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:to:cc:references:from:subject:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; s=default; bh=ZoBJ8y5uI6BBnwsQF72wvL PxNW0=; b=paBT4toBCuWoFhqoX9SkYDvBtBpE1ihPRpV5ajmJx/Hyf0zqCsOC/Z B/7vPYDIAAdbyYAG9XdrBSmW8Ot8fBRVSLiUzqISodzzOmx+UOHwIMYvb5G3Goe/ GXMjePyq86CNbkY8i61XOZbFqL68Mg699sFRVbMAGMwSGVBwaCkUk= Received: (qmail 9805 invoked by alias); 18 Jul 2019 20:31:58 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 9795 invoked by uid 89); 18 Jul 2019 20:31:57 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mail-qt1-f171.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=to:cc:references:from:openpgp:autocrypt:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=3moVmIFHx6iDX9eXNfwP4Af6PpxZiisxsYKqNT9dWUY=; b=PjHK1RpNL9KydpSSp3Xxkqq7E1NUhymV253Fd8qBBt8Zn7vwBpbMQQSrqpcsz7Qyai KE0/QueTb+YZtJdPAnbFhjK3ALTjH5XTIO9RPVpvPwEWvDmkMA6DCYcx0P5r4gQa6tuj bwPfcLsrP+4Oayv37vg+V/mzje9IYq3/oOVF9aXuTw9RFthFjJCw17cjIAYzIorbJ51k NrCFlG/sUDIuW7LDiyyrVIIsDj13FcSV6BDjM+2PNij0+9fN31OAGEsncoWDBfXDMcA6 AqKGX93Oct5gkOsKfMFON+FehQTEH2AiRD9e8P4DmvixEIjRnKRNThd7Jk9n96DOETk1 G1Gw== To: Florian Weimer Cc: libc-alpha@sourceware.org References: <20190712072103.D3DBC24003A@gemini.denx.de> <874l3mjgi6.fsf@oldenburg2.str.redhat.com> <20190716145216.1C7CE240085@gemini.denx.de> <875zo0911b.fsf@oldenburg2.str.redhat.com> <20190717160021.75EB224003E@gemini.denx.de> <87h87k7ilf.fsf@oldenburg2.str.redhat.com> <20190717181811.5902cd5e@jawa> <87ftn3xija.fsf@oldenburg2.str.redhat.com> From: Adhemerval Zanella Openpgp: preference=signencrypt Subject: Re: Accelerating Y2038 glibc fixes Message-ID: <0a59e20b-e941-e71a-5d4c-cda8088617c3@linaro.org> Date: Thu, 18 Jul 2019 17:31:51 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <87ftn3xija.fsf@oldenburg2.str.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit On 18/07/2019 16:13, Florian Weimer wrote: > * Adhemerval Zanella: > >> So what about to not add a user-selected way to set the time_t size >> (as off_t) and just enable time64_t support and sets is as default for >> build with a minimum kernel of v5.1 (if I recall correctly as being the >> one that added time64 support)? > > Does this mean that some developers see a glibc 2.31 with a 32-bit > time_t on i386, and others see a 64-bit time_t? > >> It will move all time32 support as compat symbols for the required ABI, >> without an option to select it through a build flag. Newer ports will >> just have the expected symbol names, no tinkering needed. > > But if we build glibc with pre-5.1 kernel headers, you will get the > legacy interface? My idea is to setup based on --enable-kernel and add a new EI_ABIVERSION when time64 is used. So, depending on how glibc is built, developers will indeed see a different time_t. Legacy builds won't build any time64 support, even with newer kernels. Build set with --enable-kernel will automatically set time_t as time64 and redirect the required interfaces to the new symbols ones (similar to LFS, but transparently as _FILE_OFFSET_BITS=64 as being set as default). Newer 32-bit ports won't require anything like this as expected. I still think that in long term this initial bump transition is better than to the complexity from mixed support.