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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76E8FC43381 for ; Tue, 12 Jan 2021 00:40:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5465622510 for ; Tue, 12 Jan 2021 00:40:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391660AbhALAZQ (ORCPT ); Mon, 11 Jan 2021 19:25:16 -0500 Received: from mail.skyhub.de ([5.9.137.197]:56758 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404235AbhALAKJ (ORCPT ); Mon, 11 Jan 2021 19:10:09 -0500 Received: from zn.tnic (p200300ec2f088f0064dd88f751605e0c.dip0.t-ipconnect.de [IPv6:2003:ec:2f08:8f00:64dd:88f7:5160:5e0c]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id E011C1EC04CB; Tue, 12 Jan 2021 01:09:27 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1610410168; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=hiQ2aT0sAgvveKCKw+n+ctbke87ZB3mfcJ48rJ15WaA=; b=NsLcVrbXvB8OcvgEN8y1ZJhIB4cKQy1qxYzOGUW0gOgqXZBZw9fhwTrH4s3Ab8Ys9vAmKC ETk1YqW4/5NjMpkALcoZxvI+YzsxaEQZiqLmXUYShLWlgItlAbAgGMRQrg9eU3i46ENf8L bkO8j99EZtA1GiOIuXGUs0+76MEHRJ4= Date: Tue, 12 Jan 2021 01:09:23 +0100 From: Borislav Petkov To: Krzysztof Mazur Cc: Thomas Gleixner , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] x86/lib: don't use MMX before FPU initialization Message-ID: <20210112000923.GK25645@zn.tnic> References: <20201228160631.32732-1-krzysiek@podlesie.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201228160631.32732-1-krzysiek@podlesie.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 28, 2020 at 05:06:31PM +0100, Krzysztof Mazur wrote: > When enabled, the MMX 3DNow! optimized memcpy() is used very early, > even before FPU is initialized. It worked fine, but commit > 7ad816762f9bf89e940e618ea40c43138b479e10 ("x86/fpu: Reset MXCSR > to default in kernel_fpu_begin()") broke that. After that commit > the kernel crashes just after "Booting the kernel." message. Have you figured out in the meantime what exactly is causing the breakage? Does it boot if you comment out + if (boot_cpu_has(X86_FEATURE_FPU)) + asm volatile ("fninit"); in kernel_fpu_begin()? I'm guessing K7 doesn't have X86_FEATURE_XMM so the LDMXCSR won't matter... Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette