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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E46DAC433F5 for ; Thu, 4 Nov 2021 18:00:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEAB1611EE for ; Thu, 4 Nov 2021 18:00:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234023AbhKDSDb (ORCPT ); Thu, 4 Nov 2021 14:03:31 -0400 Received: from mail.skyhub.de ([5.9.137.197]:51568 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234029AbhKDSD3 (ORCPT ); Thu, 4 Nov 2021 14:03:29 -0400 Received: from zn.tnic (p200300ec2f0f2b00d41ed3305b1ea114.dip0.t-ipconnect.de [IPv6:2003:ec:2f0f:2b00:d41e:d330:5b1e:a114]) (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 5635A1EC0521; Thu, 4 Nov 2021 19:00:50 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1636048850; 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=JRN1wnmb72V2+aOEZgc4zMu+7diDFEtY3HFFtJI0eMo=; b=mfhPIi+brEbAvzMbXqyoLhqDsB04W4L4PyqHGInFRz5+aSAs1k5tu/jW5NMS9VWsLcnG97 nQheq4X+DE38xoEVG9u19oJ4eD4TG+dR0+vX7RU+YZssk2pwdvp4zJxtvoKor3qUY7dOM0 M1o6TRH1uEjDZorxPaqDPYK3qwD7Wig= Date: Thu, 4 Nov 2021 19:00:43 +0100 From: Borislav Petkov To: Peter Zijlstra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz Subject: Re: [RFC][PATCH 02/22] x86,mmx_32: Remove .fixup usage Message-ID: References: <20211104164729.226550532@infradead.org> <20211104165524.625383149@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211104165524.625383149@infradead.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 04, 2021 at 05:47:31PM +0100, Peter Zijlstra wrote: > This code puts an exception table entry on the "PREFIX" instruction to > overwrite it with a jmp.d8 when it triggers an exception. Except of > course, our code is no longer writable, also SMP. > > Replace it with ALTERNATIVE, the novel > > XXX: arguably we should just delete this code Yah, might as well. Wikipedia says the last AMD CPU which supports 3DNow is A8-3870K which is family 0x11, i.e., 1. a real rarity 2. it is pretty much obsolete 3. even if not, it can do AMD64 4. and even if people who have it, wanna run 32-bit, they can use the normal memcpy, i.e., CONFIG_X86_USE_3DNOW=n should work there In our case, it is a bit different, though: config X86_USE_3DNOW def_bool y depends on (MCYRIXIII || MK7 || MGEODE_LX) && !UML MK7 is K7 - that is practically dead. The only thing I have no clue about are those cyrix and geode things and whether they're still actively used in some embedded gunk. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette