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 E56BFC43387 for ; Tue, 8 Jan 2019 18:58:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A76512087F for ; Tue, 8 Jan 2019 18:58:15 +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="NuhTIrml" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728642AbfAHS6O (ORCPT ); Tue, 8 Jan 2019 13:58:14 -0500 Received: from merlin.infradead.org ([205.233.59.134]:55486 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728106AbfAHS6O (ORCPT ); Tue, 8 Jan 2019 13:58:14 -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=sIpAEAGlSMv194QjCj2KclvPSTcPSpdvrQNngqRckqQ=; b=NuhTIrml0b8OtLtssq8Jlpxyc qx/Gf2ta0yggMSmEDqYZHeDkiAlhSTJYuHAqJujFd3Neknpuh0Zq8ztoNsrTz5jLZE0mlFekxDV4j UwcjAhRXAQqzdsZkyzLpmv2eri3lEK6koZbH5lbnqb3gyrDN87C8QbSbc2kjoWe6XjSsRPB/LDmcr PpU3aeJGT7253eDpDqr7J3c/NHhv5J+NC+IKYVkCNUcCp2yeDVq/euq73X+iQmsLhNrvxgu3USMFW /rW3ZKu/IBAwvkoljWxHhMXMCzyQbyFQ2kam9gl+3Cdx1F/7Y5J8hP/qSzYc4pfrkSqxYk8nl9yuR QFf5LSu6Q==; 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 1ggwZV-0003FN-IW; Tue, 08 Jan 2019 18:57:53 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 39E6020280450; Tue, 8 Jan 2019 19:57:51 +0100 (CET) Date: Tue, 8 Jan 2019 19:57:51 +0100 From: Peter Zijlstra To: Andi Kleen Cc: Adrian Hunter , Nadav Amit , Ingo Molnar , Andy Lutomirski , Josh Poimboeuf , Edward Cree , "H . Peter Anvin" , Thomas Gleixner , LKML , Nadav Amit , X86 ML , Paolo Abeni , Borislav Petkov , David Woodhouse , Alexander Shishkin , songliubraving@fb.com Subject: Re: [RFC v2 0/6] x86: dynamic indirect branch promotion Message-ID: <20190108185751.GB1900@hirez.programming.kicks-ass.net> References: <20181231072112.21051-1-namit@vmware.com> <87zhshe66w.fsf@linux.intel.com> <20190107163227.GH14122@hirez.programming.kicks-ass.net> <20190108092559.GA6808@hirez.programming.kicks-ass.net> <306d38fb-7ce6-a3ec-a351-6c117559ebaa@intel.com> <20190108101058.GB6808@hirez.programming.kicks-ass.net> <20190108172721.GN6118@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190108172721.GN6118@tassilo.jf.intel.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 Tue, Jan 08, 2019 at 09:27:21AM -0800, Andi Kleen wrote: > It doesn't work when the code is modified in place, like the > patch in the $SUBJECT. For in-place modification a-la jump_label / static_call etc. we can 'trivially' log the new instruction and the decoder can do matching in-place kcore adjustments.