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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 48B92C282C5 for ; Tue, 22 Jan 2019 13:40:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17B9B20870 for ; Tue, 22 Jan 2019 13:40:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="YFRpSOcd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728541AbfAVNkX (ORCPT ); Tue, 22 Jan 2019 08:40:23 -0500 Received: from mail.skyhub.de ([5.9.137.197]:40712 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728394AbfAVNkX (ORCPT ); Tue, 22 Jan 2019 08:40:23 -0500 Received: from zn.tnic (p200300EC2BCBD900846DD624DCCF3A9E.dip0.t-ipconnect.de [IPv6:2003:ec:2bcb:d900:846d:d624:dccf:3a9e]) (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 00F1B1EC072C; Tue, 22 Jan 2019 14:40:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1548164421; 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=PyM7CbA0hfWFqe8nBcyRd5MK+VJCiClt78A1zbWGC+s=; b=YFRpSOcdIbVVUv1tNvvtSlMnk/BsTDwjAurWXuBj9HSKqPOlsqt1tRdVebO0v2rcXx7Ghn 8F+nnZsRUv5s40ANj0j4ck6XEPU6GDlnf+3YNww69i91UkfZ5YzSBH2lH+2+VcEEklSnnU CEgaHKAILdy+ZfsCmkTsocWiT+eOxZA= Date: Tue, 22 Jan 2019 14:40:15 +0100 From: Borislav Petkov To: Oleg Nesterov Cc: Dave Hansen , Sebastian Andrzej Siewior , Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, Andy Lutomirski , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen Subject: Re: [PATCH 05/22] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Message-ID: <20190122134015.GI26587@zn.tnic> References: <20190109114744.10936-1-bigeasy@linutronix.de> <20190109114744.10936-6-bigeasy@linutronix.de> <20190116193603.GK15409@zn.tnic> <20190116224037.xkfnevzkwrck5dtt@linutronix.de> <20190117122253.GC5023@zn.tnic> <20190118211401.4komqsnvuof7563p@linutronix.de> <33f0e144-1eec-b1a1-8858-58f20d5e477d@intel.com> <20190121112117.GA32538@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190121112117.GA32538@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 21, 2019 at 12:21:17PM +0100, Oleg Nesterov wrote: > And in any case I do not understand the idea to use the second > in-kernel struct fpu. A signal handler can be interrupted by another > signal, this will need to save/restore the FPU state again. Well, we were just speculating whether doing that would simplify the code around get_sigframe() et al. But if that is an ABI, then we can't really touch it. Btw, where is that whole ABI deal about saving FPU regs on the user signal stack documented? Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.