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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 8F91FC43381 for ; Fri, 15 Feb 2019 17:40:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F3B521927 for ; Fri, 15 Feb 2019 17:40:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="URdkLOaQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729985AbfBORkz (ORCPT ); Fri, 15 Feb 2019 12:40:55 -0500 Received: from merlin.infradead.org ([205.233.59.134]:51032 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726045AbfBORky (ORCPT ); Fri, 15 Feb 2019 12:40:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=3CyfjezA+S+2MaTUVDQw70hdDLbw1EZGPKtc0T6KeLM=; b=URdkLOaQXugoIEqVbkxev5aqv BM+wmv/VzK3ZWEAoY6OfpTaKIqaJWUCzgq3ziASmdAS5rGK1A9zsBEg8Kg/QUg4Iq69ovNPoAjGr5 30DSNXn2aU8qJ+w+ycW0U+KUxXsDpse+8XzyY4Z4Z8Wy72rYRSUsO26jwXN+uAo+DKYxCYtGgsoUR U/vSDP8EjnMsbj2GPBo6LvdCiAaeFLiGDeEgXKpw8lYCLJBn7Iun75ZJgjbsBdYtLSFXo4tjgtSAj Cqkr7W+TwfawZzmUBd8n5AosfvKRp06G+ZRyGkYcD9wYqgn5ikdzmMFolLM4yqkDsSWR0bUbPDWoj r+p9EyhsA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1guhTb-0008La-CH; Fri, 15 Feb 2019 17:40:39 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8D607233D2080; Fri, 15 Feb 2019 18:40:34 +0100 (CET) Date: Fri, 15 Feb 2019 18:40:34 +0100 From: Peter Zijlstra To: Linus Torvalds Cc: Brian Gerst , Andy Lutomirski , Julien Thierry , Will Deacon , Ingo Molnar , Linux Kernel Mailing List , "linux-alpha@vger.kernel.org" , Ingo Molnar , Catalin Marinas , James Morse , "H. Peter Anvin" , valentin.schneider@arm.com, Josh Poimboeuf , Andy Lutomirski , Borislav Petkov , Denys Vlasenko , Thomas Gleixner Subject: Re: [PATCH] sched/x86: Save [ER]FLAGS on context switch Message-ID: <20190215174034.GP32494@hirez.programming.kicks-ass.net> References: <20190213144145.GY32494@hirez.programming.kicks-ass.net> <20190213154532.GQ32534@hirez.programming.kicks-ass.net> <20190213222146.GC32494@hirez.programming.kicks-ass.net> <20190214101429.GD32494@hirez.programming.kicks-ass.net> <20190214193432.GR32477@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Fri, Feb 15, 2019 at 09:18:00AM -0800, Linus Torvalds wrote: > On Thu, Feb 14, 2019 at 11:34 AM Peter Zijlstra wrote: > > > > Something like the below, right? > > > > + frame->flags = 0; > > + frame->flags = 0; > > Those are not valid flag values. > > Can you popf them? Yes. > > Do they make sense? No. > > It has the IF flag clear, for example. Is that intentional? If it is, Uhmm. yeah, that's bonkers. We should have interrupts disabled here. I'll go read up on the eflags and figure out what they _should_ be right about there. 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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 44EDEC43381 for ; Fri, 15 Feb 2019 17:40:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 13F9621927 for ; Fri, 15 Feb 2019 17:40:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="a4UHaVsY"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="URdkLOaQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13F9621927 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6+RNzUpSkCu8i1bn/0Jgv8vqDdl+1mzCC1PyKNclOTw=; b=a4UHaVsYtGiWeE AcRITE5VRADayfAQM2kwpPCEbZNRyIvZvGKPFWuwy16Nx8Zjd4ED7kpH1674haqJQAK7rC7O9to8/ iWKrI982+uE7pvsKu2w6lEb4Xe5PmmTsKRI3tL71w8GdAU03/x80kRQz1QZ9iNwS8l75aQnAN698W gYLlQKZliFIe4yFw8syeivHJalq9gqKmJYss3bT7IUY8rTf3TnI5UOJXNJ8AquJ2vzp403J5C1Wmf nWGgHIIMYICJZgTh+laF6GqW5yxcCtss4N7oVoJC8Rku3U7Tbq1a/MkMeUq26syT5sS1nk/PeCDSY wjevwHSuIu5vxCSqDGbA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1guhTi-0007FG-5E; Fri, 15 Feb 2019 17:40:46 +0000 Received: from merlin.infradead.org ([2001:8b0:10b:1231::1]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1guhTg-0007Et-H1 for linux-arm-kernel@bombadil.infradead.org; Fri, 15 Feb 2019 17:40:44 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=3CyfjezA+S+2MaTUVDQw70hdDLbw1EZGPKtc0T6KeLM=; b=URdkLOaQXugoIEqVbkxev5aqv BM+wmv/VzK3ZWEAoY6OfpTaKIqaJWUCzgq3ziASmdAS5rGK1A9zsBEg8Kg/QUg4Iq69ovNPoAjGr5 30DSNXn2aU8qJ+w+ycW0U+KUxXsDpse+8XzyY4Z4Z8Wy72rYRSUsO26jwXN+uAo+DKYxCYtGgsoUR U/vSDP8EjnMsbj2GPBo6LvdCiAaeFLiGDeEgXKpw8lYCLJBn7Iun75ZJgjbsBdYtLSFXo4tjgtSAj Cqkr7W+TwfawZzmUBd8n5AosfvKRp06G+ZRyGkYcD9wYqgn5ikdzmMFolLM4yqkDsSWR0bUbPDWoj r+p9EyhsA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1guhTb-0008La-CH; Fri, 15 Feb 2019 17:40:39 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8D607233D2080; Fri, 15 Feb 2019 18:40:34 +0100 (CET) Date: Fri, 15 Feb 2019 18:40:34 +0100 From: Peter Zijlstra To: Linus Torvalds Subject: Re: [PATCH] sched/x86: Save [ER]FLAGS on context switch Message-ID: <20190215174034.GP32494@hirez.programming.kicks-ass.net> References: <20190213144145.GY32494@hirez.programming.kicks-ass.net> <20190213154532.GQ32534@hirez.programming.kicks-ass.net> <20190213222146.GC32494@hirez.programming.kicks-ass.net> <20190214101429.GD32494@hirez.programming.kicks-ass.net> <20190214193432.GR32477@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Denys Vlasenko , Josh Poimboeuf , Julien Thierry , Brian Gerst , "H. Peter Anvin" , Will Deacon , Linux Kernel Mailing List , Andy Lutomirski , valentin.schneider@arm.com, Ingo Molnar , James Morse , Andy Lutomirski , Catalin Marinas , Borislav Petkov , Thomas Gleixner , Ingo Molnar , "linux-alpha@vger.kernel.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Feb 15, 2019 at 09:18:00AM -0800, Linus Torvalds wrote: > On Thu, Feb 14, 2019 at 11:34 AM Peter Zijlstra wrote: > > > > Something like the below, right? > > > > + frame->flags = 0; > > + frame->flags = 0; > > Those are not valid flag values. > > Can you popf them? Yes. > > Do they make sense? No. > > It has the IF flag clear, for example. Is that intentional? If it is, Uhmm. yeah, that's bonkers. We should have interrupts disabled here. I'll go read up on the eflags and figure out what they _should_ be right about there. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel