From patchwork Tue Nov 2 09:27:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 46948 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 8F7863858018 for ; Tue, 2 Nov 2021 09:31:35 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8F7863858018 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1635845495; bh=PttNVgXZDqRP6e1ByMRdHWqCGnYjCnlHugTopnlhOyk=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=l7i26+eToRqDti+jKZZV9ws8Dmvt0JITZCVzvx2fzjyDJg+reR6LHgToLkdlP624R J8Gp9tuBbSTwCkWxL8JPF5izGvt0C6rp4X5JzHdy3bwL5WNaQ0uVEv34lzxtO/qKzM 8nIfLWT+t/gtYi7ky4Rh5yXVd6CTLPWjFywS8gNI= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 7AF283857C42 for ; Tue, 2 Nov 2021 09:28:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 7AF283857C42 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-228-QNCc2lK1NO-5WazQ8e7Apw-1; Tue, 02 Nov 2021 05:27:56 -0400 X-MC-Unique: QNCc2lK1NO-5WazQ8e7Apw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EF29CA40C1; Tue, 2 Nov 2021 09:27:55 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 07E3C5D705; Tue, 2 Nov 2021 09:27:54 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH] i386: Explain why __HAVE_64B_ATOMICS has to be 0 Date: Tue, 02 Nov 2021 10:27:53 +0100 Message-ID: <87mtmmgb52.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_NUMSUBJECT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" --- sysdeps/x86/atomic-machine.h | 4 ++++ 1 file changed, 4 insertions(+) Reviewed-by: Adhemerval Zanella diff --git a/sysdeps/x86/atomic-machine.h b/sysdeps/x86/atomic-machine.h index 695222e4fa..2692d94a92 100644 --- a/sysdeps/x86/atomic-machine.h +++ b/sysdeps/x86/atomic-machine.h @@ -60,6 +60,10 @@ typedef uintmax_t uatomic_max_t; # define BR_CONSTRAINT "q" # define IBR_CONSTRAINT "iq" #else +/* Since the Pentium, i386 CPUs have supported 64-bit atomics, but the + i386 psABI supplement provides only 4-byte alignment for uint64_t + inside structs, so it is currently not possible to use 64-bit + atomics on this platform. */ # define __HAVE_64B_ATOMICS 0 # define SP_REG "esp" # define SEG_REG "gs"