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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 404E5C2B9F4 for ; Thu, 17 Jun 2021 12:42:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1CB8A613DF for ; Thu, 17 Jun 2021 12:42:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231668AbhFQMoK (ORCPT ); Thu, 17 Jun 2021 08:44:10 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:48830 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231623AbhFQMoJ (ORCPT ); Thu, 17 Jun 2021 08:44:09 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 1A4381FDCE; Thu, 17 Jun 2021 12:42:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1623933721; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6du5rShliFs1Bihe7PeBJuT9EHklARbBwoRJSKEtKeU=; b=lNHBj8bXqXTgwZrQKp4vYm9yRDk3nKf7c5FzUIFdsefnE9O2/xakcY9ph392s2J5G3ZzKj rKaJsWxr1cik2c/H0uU9dYm3QiyTOCemz4kLxVCumnTbztE1aA36v5zwehdHC2fPAaeWgj JOpqO48BqvhCIjuZFI0vFSfgvA5RZwg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1623933721; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6du5rShliFs1Bihe7PeBJuT9EHklARbBwoRJSKEtKeU=; b=BIzN87Jil0w4+rdZZlaiMgmJcqAcFHL9saHXYfKH+ghinjVRkjKOAT5SIKHqzoQf3YTanu a33I4oCgJbsJ4vBw== Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id 01321118DD; Thu, 17 Jun 2021 12:42:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1623933721; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6du5rShliFs1Bihe7PeBJuT9EHklARbBwoRJSKEtKeU=; b=lNHBj8bXqXTgwZrQKp4vYm9yRDk3nKf7c5FzUIFdsefnE9O2/xakcY9ph392s2J5G3ZzKj rKaJsWxr1cik2c/H0uU9dYm3QiyTOCemz4kLxVCumnTbztE1aA36v5zwehdHC2fPAaeWgj JOpqO48BqvhCIjuZFI0vFSfgvA5RZwg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1623933721; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6du5rShliFs1Bihe7PeBJuT9EHklARbBwoRJSKEtKeU=; b=BIzN87Jil0w4+rdZZlaiMgmJcqAcFHL9saHXYfKH+ghinjVRkjKOAT5SIKHqzoQf3YTanu a33I4oCgJbsJ4vBw== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id tI7+OhhDy2BELAAALh3uQQ (envelope-from ); Thu, 17 Jun 2021 12:42:00 +0000 Date: Thu, 17 Jun 2021 14:41:48 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: LKML , Andy Lutomirski , Dave Hansen , Fenghua Yu , Tony Luck , Yu-cheng Yu , Sebastian Andrzej Siewior , Peter Zijlstra , Kan Liang Subject: Re: [patch V2 21/52] x86/fpu: Get rid of copy_supervisor_to_kernel() Message-ID: References: <20210614154408.673478623@linutronix.de> <20210614155355.841581418@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210614155355.841581418@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 14, 2021 at 05:44:29PM +0200, Thomas Gleixner wrote: > If the fast path of restoring the FPU state on sigreturn fails or is not > taken and the current task's FPU is active then the FPU has to be > deactivated for the slow path to allow a safe update of the tasks FPU > memory state. > > With supervisor states enabled, this requires to save the supervisor state > in the memory state first. Supervisor states require XSAVES so saving only > the supervisor state requires to reshuffle the memory buffer because XSAVES > uses the compacted format and therefore stores the supervisor states at the > beginning of the memory state. That's just an overengineered optimization. > > Get rid of it and save the full state for this case. > > Signed-off-by: Thomas Gleixner > Reviewed-by: Andy Lutomirski > --- > arch/x86/include/asm/fpu/xstate.h | 1 > arch/x86/kernel/fpu/signal.c | 13 +++++--- > arch/x86/kernel/fpu/xstate.c | 55 -------------------------------------- > 3 files changed, 8 insertions(+), 61 deletions(-) Simplification? To the FPU stinking pile of turds? Hell yeah! Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg