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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 108CCC43219 for ; Fri, 3 May 2019 15:09:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D697D205ED for ; Fri, 3 May 2019 15:09:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="XVMEwTvg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728213AbfECPJk (ORCPT ); Fri, 3 May 2019 11:09:40 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:43712 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727687AbfECPJk (ORCPT ); Fri, 3 May 2019 11:09:40 -0400 Received: by mail-pg1-f194.google.com with SMTP id t22so2852063pgi.10 for ; Fri, 03 May 2019 08:09:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=hp/Tj1QYz56VfTMd1RiR2FT6yvDdqYC2zjWo8LyAtkA=; b=XVMEwTvgSW0fLQs1WlzPcg8PmDBpqQLEQk+l6MRhlmpMcbdm4grgueXWpP8gUgJHwa 5UcAYa8QLpXmeyoTf4aZKyeRiUhlp6p8Exru114uSeqRCUSO4AT0Rj0P6+gAgzPfAdKv 96iLl5UuNdjG1WzfWwaAMoL9pTj6QfEbQXLZ0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=hp/Tj1QYz56VfTMd1RiR2FT6yvDdqYC2zjWo8LyAtkA=; b=EJ6VJqHM7duPVGFvFqYBM7XDMyhLDpQEjIIqHLPjUj8vql3yhWZsUsdmZ09mXYf0t0 TkDcM9Ss0+d1O+qstj+gdUDv2fZ8XxqLleUX7UaCASC7raBtAtQ6Pr+J3c9YpMLXEruc IKjjZ5rdb4/Ag5a3tzo2j/vOrl6YT76yB9hvprr8lvDGxX+7Vfju1tZNbSTRSdiYEqgc uAobeE61lTzCEzmcobXgBew6f+sWRUE2kPD9L8aqHefWWHS+iXhlVDP0lPhi8ej5Mjz1 3RmAGJ5u5SqnPLctmYyFdXB7hDREDUlSF1uQdF1AzxvTyqJJpdzAGiM5U1bTohjPph6m Q5mw== X-Gm-Message-State: APjAAAXshUyT0MDrqklrGZoj91GWsVgOKKad+790ZgkPzAa8ztwkbfo0 YLczQPQa6YaL35sA+7sboR7VTg== X-Google-Smtp-Source: APXvYqy+kMyXCOYXt3tkQiqhn8ghrjZXjBP+x14BUTwqGUx5FSITGx6w6TqBrjvdy1o7gXfH68Aj5Q== X-Received: by 2002:a65:6644:: with SMTP id z4mr10890842pgv.300.1556896167237; Fri, 03 May 2019 08:09:27 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id h189sm5627185pfc.125.2019.05.03.08.09.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 03 May 2019 08:09:26 -0700 (PDT) Date: Fri, 3 May 2019 11:09:24 -0400 From: Joel Fernandes To: Peter Zijlstra Cc: Qais Yousef , linux-kernel@vger.kernel.org, Michal Gregorczyk , Adrian Ratiu , Mohammad Husain , Srinivas Ramana , duyuchao , Manjo Raja Rao , Karim Yaghmour , Tamir Carmeli , Yonghong Song , Alexei Starovoitov , Brendan Gregg , Masami Hiramatsu , Steven Rostedt , Kees Cook , kernel-team@android.com, Daniel Borkmann , Ingo Molnar , netdev@vger.kernel.org Subject: Re: [PATCH RFC] bpf: Add support for reading user pointers Message-ID: <20190503150924.GD253329@google.com> References: <20190502204958.7868-1-joel@joelfernandes.org> <20190503121234.6don256zuvfjtdg6@e107158-lin.cambridge.arm.com> <20190503134935.GA253329@google.com> <20190503135426.GA2606@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190503135426.GA2606@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 03, 2019 at 03:54:26PM +0200, Peter Zijlstra wrote: > On Fri, May 03, 2019 at 09:49:35AM -0400, Joel Fernandes wrote: > > In > > particular, we learnt with extensive discussions that user/kernel pointers > > are not necessarily distinguishable purely based on their address. > > This is correct; a number of architectures have a completely separate > user and kernel address space. Much like how the old i386 4G:4G patches > worked. Thanks Peter for confirming.