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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 233F3C433EF for ; Wed, 20 Apr 2022 16:01:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355489AbiDTQEG (ORCPT ); Wed, 20 Apr 2022 12:04:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351205AbiDTQEC (ORCPT ); Wed, 20 Apr 2022 12:04:02 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 56199BBB for ; Wed, 20 Apr 2022 09:01:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650470474; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VxVL4ghGZnPEC5vFwYZynA+vKk4w0NQswkaaYSL7cxQ=; b=C902XPpUTqZ/Jkw3iD2Bsp+sRrHNYhzF5IMokds9CBKXfbEsx3d2aRBAX0HWVsHxaV2fob TV6VLuy7jS+UyY18oexO9mj+8XRYMOjXMlddTTF3lHliVqog/j9PV8xyl1ow2Hx/2+LSN8 ZPWoaLMDl+egu4Wz2rk6MxZcEuZu4DI= Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-482-GsIvt46tOyuTXo8zIXNtmg-1; Wed, 20 Apr 2022 12:01:12 -0400 X-MC-Unique: GsIvt46tOyuTXo8zIXNtmg-1 Received: by mail-qt1-f198.google.com with SMTP id fp30-20020a05622a509e00b002f33ea61111so1255088qtb.22 for ; Wed, 20 Apr 2022 09:01:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=VxVL4ghGZnPEC5vFwYZynA+vKk4w0NQswkaaYSL7cxQ=; b=A87eRp+QG/oGW6XVCEeS77sK2M8erE/ykV0yAYat4EvivvWfglJQysqeBfxmw9lF7F FRwelxnnjw3lyipX4X4U3OHnoOiq3EZdOY65ULq48HKkATcj3nKviEH4mbX4Pjt892pG kNGYghBecMK27Rl2+tRn6DOf2/IxlfULetsWzzfBhIfOJEUNkCEDYiHN7spX2Ancneov 3YbTcKM/+HHJYqZFrL/snMQa8oNpR/lURK0tH7RAqb//WuZJuZLuxKJjKDIlYFcMfWhh 0P/Nj4Q3HTkYJNAZS7gRQtuImJ57o8UPWWt8VnKGpiwnCFNQgFVVUnpNeo/xRyLsDEdj YzGw== X-Gm-Message-State: AOAM532ok4Zr24uDTn9YCa/dOOziyzwSlKT1kHxM04tybR6X9W/PbaE3 NaiIxSfaErL6i4K6rw8yeG5Qkg6idXzk/rYx5ZPEYIqjidN/zbft1mKjK+gSvmpdD23dQBpSNQ5 BgMLYk1Qw0ijh6eu7x0eYz/oc X-Received: by 2002:ac8:7ee4:0:b0:2f1:e9e6:7200 with SMTP id r4-20020ac87ee4000000b002f1e9e67200mr14196181qtc.622.1650470472447; Wed, 20 Apr 2022 09:01:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzF2P3YQNDtZZpjeFbYaPsXv2IV95hGJOjMeb5v5TrIYcOeNkobSHTZNVj7tGL0BajRL8LkFQ== X-Received: by 2002:ac8:7ee4:0:b0:2f1:e9e6:7200 with SMTP id r4-20020ac87ee4000000b002f1e9e67200mr14196152qtc.622.1650470472217; Wed, 20 Apr 2022 09:01:12 -0700 (PDT) Received: from treble ([2600:1700:6e32:6c00::35]) by smtp.gmail.com with ESMTPSA id t4-20020ae9df04000000b0069e9a6734dbsm1709186qkf.11.2022.04.20.09.01.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Apr 2022 09:01:11 -0700 (PDT) Date: Wed, 20 Apr 2022 09:01:08 -0700 From: Josh Poimboeuf To: Peter Zijlstra Cc: x86@kernel.org, brgerst@gmail.com, jiangshanlai@gmail.com, Andrew.Cooper3@citrix.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] x86: Simplify Retpoline thunk Message-ID: <20220420160108.w3rxf3vhmgnnpplq@treble> References: <20220419204109.520779286@infradead.org> <20220419205241.280037046@infradead.org> <20220420152736.qzl3nikds6mq5nrr@treble> <20220420155116.GH2731@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220420155116.GH2731@worktop.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 20, 2022 at 05:51:16PM +0200, Peter Zijlstra wrote: > On Wed, Apr 20, 2022 at 08:27:36AM -0700, Josh Poimboeuf wrote: > > On Tue, Apr 19, 2022 at 10:41:10PM +0200, Peter Zijlstra wrote: > > > Now that we rewrite all the indirect call sites, per commit: > > > > > > 750850090081 ("x86/alternative: Implement .retpoline_sites support") > > > > > > it doesn't make sense to have the retpoline thunks be an ALTERNATIVE_2 > > > that still includes a 'naked' indirect jump. > > > > > > (this accidentally 'defunnels' i386 by going back to full retpolines) > > > > So mitigations=off no longer works on i386? > > Also true I suppose... does anybody care? /me runs like heck. > > I'd hate to make all this more complicated just because i386 tho :/ Not that I care... but at least the commit log should own up to it :-) -- Josh