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=-3.3 required=3.0 tests=AWL,BAYES_00,BODY_8BITS, 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 9557D1F461 for ; Thu, 16 May 2019 11:34:44 +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:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type :content-transfer-encoding; q=dns; s=default; b=VmgKI/rlh6pJOnXE ieE2v7hi0F4wJPf1moapGt6pBcbCxh5LdYneUovdbqXRFAyplnkiVGBVtG1DD0Kp HVui5F//8FihZ+6XIhXqyfjAmDI7zFBwerrbOUDjPH0L2gQ18o4ZmgFRnakX1q8Y q8qtcYF3C7T0id/su2Wp2+et4FM= 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:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type :content-transfer-encoding; s=default; bh=1TekJXvJ2PwTP1DlS+51S7 NmNG4=; b=DazZNtUekj70rDGBB8piT8kGKvEdIYJ6QmvMMaU8ExRQRs2LUjeuRm 7LnWKBVIaAcUB6l2Axy1u5cYPfkS8xbwJlLw/hjpcDQuuuBJXZB4E0zAVFQkyXGM VaT81O8Jdz3OjcuzL1sKAXb2oJoF6S0mi4zi0gOPb/TX0QtKt6uVY= Received: (qmail 81057 invoked by alias); 16 May 2019 11:34:42 -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 81048 invoked by uid 89); 16 May 2019 11:34:41 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mail-qt1-f194.google.com MIME-Version: 1.0 References: <20190510102713.udgjb6ilygibgd5x@sghpc.golosunov.pp.ru> <77b2e1fd-7f91-5de3-6e33-e72f00f93544@linaro.org> <4d6d5aa8-e60b-b27d-f69f-17ae26b35bbc@linaro.org> In-Reply-To: <4d6d5aa8-e60b-b27d-f69f-17ae26b35bbc@linaro.org> From: Arnd Bergmann Date: Thu, 16 May 2019 13:34:22 +0200 Message-ID: Subject: Re: Update kernel-features.h files for Linux 5.1 To: Adhemerval Zanella Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, May 16, 2019 at 1:15 PM Adhemerval Zanella wrote: > On 16/05/2019 05:08, Arnd Bergmann wrote: > > On Fri, May 10, 2019 at 5:07 PM Adhemerval Zanella > > wrote: > >> On 10/05/2019 07:27, Stepan Golosunov wrote: > >>> 09.05.2019 =D0=B2 23:00:37 +0000 Joseph Myers =D0=BD=D0=B0=D0=BF=D0= =B8=D1=81=D0=B0=D0=BB: > >>>> Linux 5.1 adds missing syscalls to the syscall table for many Linux > >>>> kernel architectures. This patch updates the kernel-features.h > >>>> headers accordingly. I believe the statfs64 structure used by alpha > >>>> matches what the new kernel syscalls use, but that should be reviewe= d > >>>> carefully. > >>>> > >>>> Tested with build-many-glibcs.py. > >>> > >>> The newly added direct ipc syscalls are different from the old ones: > >>> > >>> 1. They do not accept IPC_64. This means that __IPC_64 should be set > >>> to zero when new syscalls are used. And new syscalls can not be used > >>> for compat functions like __old_semctl. > >> > >> So it seems we will need to conditionally set __IPC_64 based on kernel > >> version. > > > > How so? I did not expect to see any libc change here at all, unless > > you mean after you stop using sys_ipc(). > > The idea is if user configure a minimum kernel version of v5.1, > sysvipc would use wire-up syscalls. So for sys_ipc the affected > architectures calls with required IPC_64, and for wire-up syscalls > IPC_64 is redefined accordingly. Ah, I see. Is there any real advantage in doing this now though? It seems to save a few cycles for each of those syscalls when building for linux-5.1+, but the cost is a significant increase in source code complexity. Arnd