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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 39F3DC433E1 for ; Mon, 20 Jul 2020 16:52:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EA3F206F2 for ; Mon, 20 Jul 2020 16:52:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="aKi09317" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729554AbgGTQww (ORCPT ); Mon, 20 Jul 2020 12:52:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728894AbgGTQwu (ORCPT ); Mon, 20 Jul 2020 12:52:50 -0400 Received: from mail-ej1-x644.google.com (mail-ej1-x644.google.com [IPv6:2a00:1450:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1AEBC0619D2 for ; Mon, 20 Jul 2020 09:52:49 -0700 (PDT) Received: by mail-ej1-x644.google.com with SMTP id o18so18781400eje.7 for ; Mon, 20 Jul 2020 09:52:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=WjwIKDNMRO86HLiza3ekP7Z4qpEbwmULQ/L4/V4YUtE=; b=aKi09317EgbufEHdPz6ybPx9SBQ3iXd5Qr1oxjOv5QrJguwLfk+bp9TvU+POgEqNC8 E9WJUEpjgUVnd4A6HMqkPY1IIekaq1PzTfjnSMhOysWqSQHFxU2VpsbyaAfBSvi55tCf OsQMetqysDIjWPonv8j8aSyT8PHbE2MY4MEap62x4hEwJiTGeKO4UE/AqW6CYkuqHJFK +jNk4cgc5ueo3XySM27EJlzHTQmL7o1dFCUGkubIzjmwWtHygQSqOr7J4KrirT0N5ii5 6jmz3r9OZwZaSF0lhj6qB061kySusc6q4saf79ctFwnqDim1fh9xHMNQHSN4aeXTLI+e WmFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=WjwIKDNMRO86HLiza3ekP7Z4qpEbwmULQ/L4/V4YUtE=; b=cKa9gojqSQRWUf7gOYZ3VGbjxsE4jJf5ONCfS4WhzfBplQ3FwUHigQp02a249GBC6E qNn5YDygaZNY4RZ5ySpLrmPAliS5G+TwJZrA+gEoYq5motpwAi3kGg3nBegpy93/rxet RDcTJwXT9Wmtp6NjOB4fT37zI2xD3+eL/2BBbgL8ecC/C9azbfp/DmHXnrRTIPJVweXZ MakB49Ii4mfAsgBURbODRjXAXqifs8q/aopRbQOEFcWmXSX2fvjgzBaPRCIodbVmlK0g 44YgskfUuF1/duhfYtygroT8hU3EFQZOUwSe8aVX5sqkaOlRvGorAJp1LkAQCUOxd9gS K+kQ== X-Gm-Message-State: AOAM530ykf5G3Bg7NKsqQ13PU0om/SQTBtTEU5LD546h0Wak8ARENqgB ia4z4FY04dvtMz27KVsTH6GZqU6f4Zy0nLnxLwOFIA== X-Google-Smtp-Source: ABdhPJwXfmksCBX85u+pwB/9F5hgtRX4ZE8Dkw8qbJ6G2uTpNqzPbNioN4uT7/TWkHbxi+iplWhAeGWkg23vKqV2cIc= X-Received: by 2002:a17:906:6959:: with SMTP id c25mr21009671ejs.375.1595263968366; Mon, 20 Jul 2020 09:52:48 -0700 (PDT) MIME-Version: 1.0 References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-5-samitolvanen@google.com> <20200624212737.GV4817@hirez.programming.kicks-ass.net> <20200624214530.GA120457@google.com> <20200625074530.GW4817@hirez.programming.kicks-ass.net> <20200625161503.GB173089@google.com> <20200625200235.GQ4781@hirez.programming.kicks-ass.net> <20200625224042.GA169781@google.com> <20200626112931.GF4817@hirez.programming.kicks-ass.net> <20200717133645.7816c0b6@oasis.local.home> <20200717140545.6f008208@oasis.local.home> In-Reply-To: <20200717140545.6f008208@oasis.local.home> From: Sami Tolvanen Date: Mon, 20 Jul 2020 09:52:37 -0700 Message-ID: Subject: Re: [RFC][PATCH] objtool,x86_64: Replace recordmcount with objtool To: Steven Rostedt Cc: Peter Zijlstra , Masahiro Yamada , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux , Kernel Hardening , linux-arch , linux-arm-kernel , linux-kbuild , LKML , linux-pci@vger.kernel.org, X86 ML , Josh Poimboeuf , Matt Helsley Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 17, 2020 at 11:05 AM Steven Rostedt wrote: > > On Fri, 17 Jul 2020 10:47:51 -0700 > Sami Tolvanen wrote: > > > > Someone just submitted a patch for arm64 for this: > > > > > > https://lore.kernel.org/r/20200717143338.19302-1-gregory.herrero@oracle.com > > > > > > Is that what you want? > > > > That looks like the same issue, but we need to fix this on x86 instead. > > Does x86 have a way to differentiate between the two that record mcount > can check? I'm not sure if looking at the relocation alone is sufficient on x86, we might also have to decode the instruction, which is what objtool does. Did you have any thoughts on Peter's patch, or my initial suggestion, which adds a __nomcount attribute to affected functions? Sami