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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 ABA5AC4742C for ; Tue, 10 Nov 2020 13:53:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0023520825 for ; Tue, 10 Nov 2020 13:53:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="eb6P/gsX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730692AbgKJNx0 (ORCPT ); Tue, 10 Nov 2020 08:53:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726721AbgKJNxZ (ORCPT ); Tue, 10 Nov 2020 08:53:25 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69FD8C0613CF for ; Tue, 10 Nov 2020 05:53:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=/C4iu3Yy2tDaDWFCW7MkzfeRGvHzVl77Kf41stSo9uM=; b=eb6P/gsXFXuyFBnomD95KO75q0 IQvIQ/mFOvGSCXYn/36oewHdlm2Vst7ULnNyH0/+azw0ZG6v2IcZZJU/t3KcFNhSgioQEO6lXvLbN flZPpl/c0Te8eWMXuR6zVpw9GAvlcBk1ojjYpMgLZ1OXXK5TPpcOJpB86DB4ssSDdT9/Bvln3voFy M0Ozkr2Gly8PsYevwKjs0r58wyGgLwzKkG+b75cErWrxGVK18/mtjFj0TpIJi1PxWzA2hrxRWvYem c+xpLW4QY6/fGa0KzUMGq2X+m7bT4edSKrCQ3O89HghoMQfuqWWr1tqgLN6Y5dsVP4tSuxd4jMAfd mhufrKpA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kcU5G-0001PS-PP; Tue, 10 Nov 2020 13:53:19 +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 9D5E8301E02; Tue, 10 Nov 2020 14:53:15 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 90CE729A566CB; Tue, 10 Nov 2020 14:53:15 +0100 (CET) Date: Tue, 10 Nov 2020 14:53:15 +0100 From: Peter Zijlstra To: Frederic Weisbecker Cc: LKML , Mel Gorman , Michal Hocko , Thomas Gleixner , "Paul E . McKenney" , Ingo Molnar , Michal Hocko Subject: Re: [RFC PATCH 1/7] static_call/x86: Add __static_call_returnl0() Message-ID: <20201110135315.GO2611@hirez.programming.kicks-ass.net> References: <20201110005609.40989-1-frederic@kernel.org> <20201110005609.40989-2-frederic@kernel.org> <20201110095515.GA2594@hirez.programming.kicks-ass.net> <20201110101307.GO2651@hirez.programming.kicks-ass.net> <20201110134223.GB48886@lothringen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201110134223.GB48886@lothringen> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 10, 2020 at 02:42:23PM +0100, Frederic Weisbecker wrote: > On Tue, Nov 10, 2020 at 11:13:07AM +0100, Peter Zijlstra wrote: > > On Tue, Nov 10, 2020 at 10:55:15AM +0100, Peter Zijlstra wrote: > > > On Tue, Nov 10, 2020 at 01:56:03AM +0100, Frederic Weisbecker wrote: > > > > > > > [fweisbec: s/disp16/data16, integrate into text_get_insn(), elaborate > > > > comment on the resulting insn, emulate on int3 trap, provide validation, > > > > uninline __static_call_return0() for HAVE_STATIC_CALL] > > > > > Why did you add full emulation of this? The patch I send to you used the > > > text_poke_bp(.emulate) argument to have it emulate an actual call to the > > > out-of-line version of that function. > > > > > > That should work fine and is a lot less code. > > > > For reference; the below is what I send you. Actually doing the > > __static_call_return0() call while we poke the magic XOR instruction is > > much simpler. > > Ok I'll get back to that. I'll just tweak a bit static_call_validate() > so that it is aware of that instruction. Ah yes indeed!