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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3FE8CC4BA0A for ; Wed, 26 Feb 2020 08:05:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12C4D21556 for ; Wed, 26 Feb 2020 08:05:57 +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="PApiq7Wh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727463AbgBZIF4 (ORCPT ); Wed, 26 Feb 2020 03:05:56 -0500 Received: from merlin.infradead.org ([205.233.59.134]:38904 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727129AbgBZIFz (ORCPT ); Wed, 26 Feb 2020 03:05:55 -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; bh=ByKqs5RS8oVptfO5+UU1Er07nuxy8TMvTUVvNbxzm6A=; b=PApiq7WhmnjBBZAPe8x1FZW158 EdwNaWEjNKrxU4tG/fRUWVUcb5ibaNqzUDYU2Fk/o+99ZYaW4hB3vSw39py727qVQCmD/zOk6k/Db n3rCsINt0mg8IieM1T9mSTQ4VsjaEndJSDLUKT+E4B5Umvl5/FAlUIS7qi1Gt7AoRXzgqPoDBYc5c NzCOB/3QqdT024JJ6ZAXycL8JsWLHAUo35Z2e53EzfRLV9Y3dQriRJ1ahACVDXr4tkt4g19yLwYk/ T4zv5sOt+ksNijh9u+/8GR9nIr3bBD3Y7RPd4eXEZkWLS6DKs/uskogf1Uc/J+1G27zLgNS0CYgMi 3JAT3WsA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j6rhN-0007Dg-T3; Wed, 26 Feb 2020 08:05:42 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 9D519300478; Wed, 26 Feb 2020 09:03:43 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id EAB93203E18D3; Wed, 26 Feb 2020 09:05:38 +0100 (CET) Date: Wed, 26 Feb 2020 09:05:38 +0100 From: Peter Zijlstra To: Thomas Gleixner Cc: LKML , x86@kernel.org, Steven Rostedt , Brian Gerst , Juergen Gross , Paolo Bonzini , Arnd Bergmann Subject: Re: [patch 13/16] x86/entry: Move irqflags and context tracking to C for simple idtentries Message-ID: <20200226080538.GO18400@hirez.programming.kicks-ass.net> References: <20200225223321.231477305@linutronix.de> <20200225224145.444611199@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200225224145.444611199@linutronix.de> 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 Tue, Feb 25, 2020 at 11:33:34PM +0100, Thomas Gleixner wrote: > --- a/arch/x86/include/asm/idtentry.h > +++ b/arch/x86/include/asm/idtentry.h > @@ -7,14 +7,31 @@ > > #ifndef __ASSEMBLY__ > > +#ifdef CONFIG_CONTEXT_TRACKING > +static __always_inline void enter_from_user_context(void) > +{ > + CT_WARN_ON(ct_state() != CONTEXT_USER); > + user_exit_irqoff(); > +} > +#else > +static __always_inline void enter_from_user_context(void) { } > +#endif > + > /** > * idtentry_enter - Handle state tracking on idtentry > * @regs: Pointer to pt_regs of interrupted context > * > - * Place holder for now. > + * Invokes: > + * - The hardirq tracer to keep the state consistent as low level ASM > + * entry disabled interrupts. > + * > + * - Context tracking if the exception hit user mode > */ > static __always_inline void idtentry_enter(struct pt_regs *regs) > { > + trace_hardirqs_off(); > + if (user_mode(regs)) > + enter_from_user_context(); > } So: asm_exc_int3 exc_int3 idtentry_enter() enter_from_user_context if (context_tracking_enabled()) poke_int3_handler(); Is, AFAICT, completely buggered. You can't have a static_branch before the poke_int3_handler that deals with text_poke.