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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 138BDC433DB for ; Mon, 21 Dec 2020 21:23:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A886722D49 for ; Mon, 21 Dec 2020 21:23:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725969AbgLUVXp (ORCPT ); Mon, 21 Dec 2020 16:23:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725791AbgLUVXo (ORCPT ); Mon, 21 Dec 2020 16:23:44 -0500 Received: from mail-qt1-x82b.google.com (mail-qt1-x82b.google.com [IPv6:2607:f8b0:4864:20::82b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00373C0613D3 for ; Mon, 21 Dec 2020 13:23:03 -0800 (PST) Received: by mail-qt1-x82b.google.com with SMTP id 7so7674208qtp.1 for ; Mon, 21 Dec 2020 13:23:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=hvt27dTXDiSjMU6MIcLPLG5yEyjYiKStuEJMa1eqpVM=; b=ADjHnaygiDeqRjgU2aRMkXr7J5W/tzZ5K52ugZR6Pas3mXN0y/mRa6WAp/Uqf0cY0i b7fvBrnGBjrt6QmGSTq0nKqwhOt4u6Hv1JSwIYST9Jd1/1Tnnc9+Xgjz8+5xolSVNaTz YEkqIRAnsrI6U+mKUFMVFkLD4Oi8ziAL2bbd2D9zznutIcqsDVZK56VqYFxJ+7ISAHH3 fReRQYTq8bEBX27sWsQYytUfGGuZb/TZyJ+hKKoJ5OShy456UU80+S/F82saK65wCp3b /Jxf7V8Q5wnNC69O2UF+NW81ausjfk7T1q1AdY1apZQh2lpSIqm6dtjXeygSEpovSaQi hONQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=hvt27dTXDiSjMU6MIcLPLG5yEyjYiKStuEJMa1eqpVM=; b=tcgMuVA969Gg+UpWmZS+YqJOP53aMQb1iHYT1JChXvz0+dKgrrixHyYxBaZ90gv5Xd hVIHQUCZ+5/4Tmv7JCYeQPgZV6CjnWHM+YoAYR/2EAvWdCmFSIi9MlhlXgjWrz74JPdj PC/jgNXemO3j1fRsVzYcuSY5/FF5nsXzUi11DpE6Z3J5qqqhFS+aQxWmJLsqTHpf7q1K 5YI60QNX456uxPaiklf3t/0dc+6qHC0W1D3PGQMkmEc6aIXLjeBnggxldbmKNfkB3kuS jTTCRniz4uQEGtVvXOlL8FrPNH6N5piB9lBQhzDI4UmeWXi47IIukfg+km0e2jB2HCuf dBBg== X-Gm-Message-State: AOAM531Vo5vPx5bfpcC5Qeny6rGBBKPOygjYYgSBs2XZcJWCLOVGBS9A AH6pExtycP8B8uyMaFly3uc= X-Google-Smtp-Source: ABdhPJx25tQ4SHAkInOq5XlAttX99/xXCC3l8CpjvpnKkVeRfUhVrpgBNF0bgPfyY3yy7XCjRFQb1w== X-Received: by 2002:ac8:3a63:: with SMTP id w90mr18297507qte.225.1608585783083; Mon, 21 Dec 2020 13:23:03 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id l1sm11461151qtb.42.2020.12.21.13.23.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Dec 2020 13:23:02 -0800 (PST) Sender: Arvind Sankar From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Mon, 21 Dec 2020 16:23:00 -0500 To: Nick Desaulniers Cc: Arvind Sankar , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , clang-built-linux , Tom Lendacky , LKML Subject: Re: [PATCH] x86/cmdline: Disable jump tables for cmdline.c Message-ID: References: <20200903023056.3914690-1-nivedita@alum.mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 21, 2020 at 11:14:39AM -0800, Nick Desaulniers wrote: > On Wed, Sep 2, 2020 at 7:31 PM Arvind Sankar wrote: > > > > When CONFIG_RETPOLINE is disabled, Clang uses a jump table for the > > switch statement in cmdline_find_option (jump tables are disabled when > > CONFIG_RETPOLINE is enabled). This function is called very early in boot > > from sme_enable() if CONFIG_AMD_MEM_ENCRYPT is enabled. At this time, > > Hi Arvind, sorry I missed this when you first sent it. I'm going > through and mass deleting my inbox (email bankruptcy) but noticed > this. I couldn't reproduce jump tables in cmdline_find_option with > CONFIG_RETPOLINE disabled but CONFIG_AMD_MEM_ENCRYPT on today's > linux-next. Can you please confirm that this is still an issue? I will > reread the disassembly, but it looks like a bunch of cmp/test+jumps. > The patch got merged and is in v5.10 -- are you testing with it reverted or just plain linux-next?