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[2620:137:e000::1:20]) by mx.google.com with ESMTP id r9-20020a05640251c900b00423e4228df0si3165048edd.497.2022.04.20.22.25.01; Wed, 20 Apr 2022 22:25:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=AO6VC09n; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354999AbiDTPaa (ORCPT + 99 others); Wed, 20 Apr 2022 11:30:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234586AbiDTPa3 (ORCPT ); Wed, 20 Apr 2022 11:30:29 -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 30B3045AC7 for ; Wed, 20 Apr 2022 08:27:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650468462; 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=/8Ka6GvZhFRkfzLxzT1UbmtWFPhhmqZ+X1PdVTRfmEs=; b=AO6VC09n2J6MJ/s9sl/fEswPs/0FYODTaN+8jws6eUCAwvIgjjkXx6rBDVLbMsx61VrrBq mu8RNVKEf+oznrXc0Tue2bPxcR8rN8ot5+JsxPDv26LkwOgmKpRUbO4k0DkeCi3B/4SV1i aqnCDVhsf/2CkML0Knhkf9X79YB0Qps= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-426-XP-iuyOZNwad_uqyqIU4Jg-1; Wed, 20 Apr 2022 11:27:40 -0400 X-MC-Unique: XP-iuyOZNwad_uqyqIU4Jg-1 Received: by mail-qk1-f199.google.com with SMTP id ay14-20020a05620a178e00b0069a9c319c64so1461769qkb.3 for ; Wed, 20 Apr 2022 08:27:40 -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=/8Ka6GvZhFRkfzLxzT1UbmtWFPhhmqZ+X1PdVTRfmEs=; b=h707aH821gEIO8J6pDDo0/ljbsiQGl0C9K2W0eWIMxIdCrUvipG7LX4qCZsQvFOeMv 9dY0971gM2l65jrlJ290PQvqkj0pPhBdMG2+JQEo5qUSiyHkJ+19PV2YkTL+yJFpZc/m 9H/RbEaIhdm3UpsA3jRnpT2js8DMuzvN131OwOk026LQVE5FowOb5dS0o+4q0wIEfDh0 FMtcI6USJkUwcwkpDhkFyJ4FM1G9vzyPn1ToLTFmXh8SHZeMmSFzMBRJQ0S3iWFZCmSl vkDooH2nAGrloYumj7MssXwmdVztCfPkVmD38Ifw9ggkEzSqfmDz2MhMcnbtQk88q49E ufqg== X-Gm-Message-State: AOAM531rkUG6eGtlxBmVlEaai/ORdPZ3M9VAlHua7wCNnketc+Hdu2Nh kK33Igk//+SvTMjp8DZj2m53xmECO/kZtWnp2GQHfeqY8v3rg205kHlNYNZIDe0zx0TN1sKzeuy x6NYlSPmHmibEwwGrlF+yyICB X-Received: by 2002:a05:622a:46:b0:2f2:9b12:5375 with SMTP id y6-20020a05622a004600b002f29b125375mr7452067qtw.625.1650468460271; Wed, 20 Apr 2022 08:27:40 -0700 (PDT) X-Received: by 2002:a05:622a:46:b0:2f2:9b12:5375 with SMTP id y6-20020a05622a004600b002f29b125375mr7452046qtw.625.1650468459998; Wed, 20 Apr 2022 08:27:39 -0700 (PDT) Received: from treble ([2600:1700:6e32:6c00::35]) by smtp.gmail.com with ESMTPSA id c23-20020a05620a201700b0069c7c8d1b9fsm1621839qka.21.2022.04.20.08.27.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Apr 2022 08:27:39 -0700 (PDT) Date: Wed, 20 Apr 2022 08:27:36 -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: <20220420152736.qzl3nikds6mq5nrr@treble> References: <20220419204109.520779286@infradead.org> <20220419205241.280037046@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220419205241.280037046@infradead.org> X-Spam-Status: No, score=-3.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Is funneling even a concern on i386? I don't think it has eIBRS anyway, or does it? -- Josh