From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 15109C4167B for ; Sun, 26 Nov 2023 12:45:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r7EVH-00058d-6I; Sun, 26 Nov 2023 07:44:52 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r7EVE-00058O-Pg for qemu-devel@nongnu.org; Sun, 26 Nov 2023 07:44:48 -0500 Received: from zproxy2.enst.fr ([2001:660:330f:2::dd]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r7EV8-0006zw-AH for qemu-devel@nongnu.org; Sun, 26 Nov 2023 07:44:47 -0500 Received: from localhost (localhost [IPv6:::1]) by zproxy2.enst.fr (Postfix) with ESMTP id C4CE2805F7; Sun, 26 Nov 2023 13:44:35 +0100 (CET) Received: from zproxy2.enst.fr ([IPv6:::1]) by localhost (zproxy2.enst.fr [IPv6:::1]) (amavis, port 10032) with ESMTP id mHhWE2IvLWlf; Sun, 26 Nov 2023 13:44:35 +0100 (CET) Received: from localhost (localhost [IPv6:::1]) by zproxy2.enst.fr (Postfix) with ESMTP id 7FEF580668; Sun, 26 Nov 2023 13:44:35 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.10.3 zproxy2.enst.fr 7FEF580668 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=telecom-paris.fr; s=A35C7578-1106-11E5-A17F-C303FDDA8F2E; t=1701002675; bh=TgIjoaQr6482qDEmXy0I6CdFHdKj4Zj//PDYQaOo+1g=; h=From:To:Date:Message-ID:MIME-Version; b=GOnkkZmxrNKySE2ZqNzyTBnKsEnJz1zfYHwuleAkgABCyASj6qUoRqBBHeTry6Mbj t3NYjf/NzQ/gwga2IkGlXBGOokrxUL09lX60pqYjId2t3PYNIkTdksdtrCDSQVyRxt pl16ucPkQ4mMBA2VvpvkDBWM/LeiOE05uhgyCJnE= X-Virus-Scanned: amavis at enst.fr Received: from zproxy2.enst.fr ([IPv6:::1]) by localhost (zproxy2.enst.fr [IPv6:::1]) (amavis, port 10026) with ESMTP id I1-2-mo9AHT8; Sun, 26 Nov 2023 13:44:35 +0100 (CET) Received: from buffy (unknown [IPv6:2a01:e34:ec63:e440:3bba:56bc:e324:3f15]) by zproxy2.enst.fr (Postfix) with ESMTPSA id 4564D805F7; Sun, 26 Nov 2023 13:44:35 +0100 (CET) References: <6826113a-d428-401e-b5a3-56ad5d8fbaa4@gmail.com> User-agent: mu4e 1.10.8; emacs 29.1 From: Samuel Tardieu To: Petr Cvek Cc: pbonzini@redhat.com, marcel.apfelbaum@gmail.com, mst@redhat.com, qemu-devel@nongnu.org Subject: Re: [PATCH] qemu/timer: Don't use RDTSC on i486 Date: Sun, 26 Nov 2023 13:37:44 +0100 In-reply-to: <6826113a-d428-401e-b5a3-56ad5d8fbaa4@gmail.com> Message-ID: <87msv065vx.fsf@telecom-paris.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2001:660:330f:2::dd; envelope-from=samuel.tardieu@telecom-paris.fr; helo=zproxy2.enst.fr X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, T_SPF_HELO_TEMPERROR=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Petr Cvek writes: > GCC defines __i386__ for i386 and i486, which both lack RDTSC=20 > instruction. > The i386 seems to be impossible to distinguish, but i486 can be=20 > identified > by checking for undefined __i486__. Couldn't you check for an undefined __tune_i386__, which would be=20 set by both GCC and LLVM when using -march=3Di386. Sam --=20 Samuel Tardieu T=C3=A9l=C3=A9com Paris - Institut Polytechnique de Paris