Received: by 2002:ac0:a5b6:0:0:0:0:0 with SMTP id m51-v6csp1000432imm; Thu, 31 May 2018 13:16:21 -0700 (PDT) X-Google-Smtp-Source: ADUXVKIxFZkSS+eeo9T1pm3grdeX8W3RmgdgbpEYDFXejOATofP39B2Get5Ty/QURpJe23fkhwUM X-Received: by 2002:a63:9902:: with SMTP id d2-v6mr1190525pge.166.1527797781395; Thu, 31 May 2018 13:16:21 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1527797781; cv=none; d=google.com; s=arc-20160816; b=dLwl96tTnpx1ELOYRZiFZoJwHnbVEylONQBeBTkjQtLXSy1YDEmapydKXvb0Oh9CUA 5zYOK8E1N160HtDNTEM6mI/+gZ2vsamZqym0RfrjLFmJMYYpJnxOtDZ3oz5pjFHc0MLi CBcjDKDoMZNbiGZoFtfJcKmVmuZq4mQ6fM3OZlggLyUU5hG5FYIpsKyyzoyUme7YJa/o g5A7MXInKvCAdE8WtkOKMD8NYqycmogYT1iWlu3U7A+AzrsVLTD52bak3otiWN0yzuD6 E2VOikJ4rJWN9SUucl0FSKdOZctvSfHydKROLwzUoR28tHOROXYWr7u6PxUhdIWpKmPM +2+w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature :arc-authentication-results; bh=E/fN0106h4BBpwwbKZHdeWuVLu6ibbe60+KqwYIPy1s=; b=zdU6F2f2aqZKff9WCELwnohUJFOyLtDHBqqfx+2PVZJt4JCH1RiIkybFj7bJS5QYDm gmHSPOyGR0sSzppDFjX1AP/9vAoYqkKpUSf+/gH0LaMv0+tG40nGFDXWO1/5Vrtmv+KT bdeXc3kHgQYIZu00JRmHb0n8vnNCr6vFpgJ6AI6HOcvJVLm0SABVkaPWbmJB7oWpi/ph 3pqADy3wOSW4iHm9nLtlbda4kdPYUhV/6PDwMT8uf/qQOY1n/WXOq1bzB/dauwUxWoYd WOmE3zJt9TYldmTa1LJWqxJQkPK4gM4P8HwTdizE0ldIcIk6IR5/XfTUDUHJzPLEHtYo 4TbA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=p6HyPOo9; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id y34-v6si38057404plb.17.2018.05.31.13.16.07; Thu, 31 May 2018 13:16:21 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=p6HyPOo9; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754380AbeEaUPN (ORCPT + 99 others); Thu, 31 May 2018 16:15:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:46404 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754089AbeEaUPM (ORCPT ); Thu, 31 May 2018 16:15:12 -0400 Received: from mail-wm0-f54.google.com (mail-wm0-f54.google.com [74.125.82.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0AFFC208AD for ; Thu, 31 May 2018 20:15:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1527797712; bh=waKVwZ869/LdstpWKaIwrC1NmNTv9W82IWwEK7cXCK8=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=p6HyPOo9jBQkobp6Drv5PZvZukTKmgz2E1GlUdqmbQKRYFam3Ve4qLaQZkA++NVKe acWo5OzSas+wD0EUqzdgJr8rJejfVOiGMiZC1+NUsz1fViAvKMyhn6rbOJXjYg8WKM j6STxZd9/wcFMJLkrY16ylBbNIqkx/hYG5fW0qog= Received: by mail-wm0-f54.google.com with SMTP id a8-v6so56094791wmg.5 for ; Thu, 31 May 2018 13:15:11 -0700 (PDT) X-Gm-Message-State: APt69E2rWkB3NeL9Lt9TSxWwO3g0qnyNLmDgARuIU1K267I7WmiFJKqW wjGyJJ8FN75aiEDypflaQQ/GME7gOY4dwHzMyQk3Tg== X-Received: by 2002:a1c:dca:: with SMTP id 193-v6mr785683wmn.36.1527797710583; Thu, 31 May 2018 13:15:10 -0700 (PDT) MIME-Version: 1.0 References: <1527789525-8857-1-git-send-email-chang.seok.bae@intel.com> <1527789525-8857-3-git-send-email-chang.seok.bae@intel.com> In-Reply-To: <1527789525-8857-3-git-send-email-chang.seok.bae@intel.com> From: Andy Lutomirski Date: Thu, 31 May 2018 13:14:59 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH V2 02/15] x86/fsgsbase/64: Make ptrace read FS/GS base accurately To: "Bae, Chang Seok" Cc: Andrew Lutomirski , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , Andi Kleen , Dave Hansen , "Metzger, Markus T" , "Ravi V. Shankar" , LKML 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 Thu, May 31, 2018 at 10:58 AM Chang S. Bae wrote: > > From: Andy Lutomirski > > ptrace can read FS/GS base using the register access API > (PTRACE_PEEKUSER, etc) or PTRACE_ARCH_PRCTL. Make both of these > mechanisms return the actual FS/GS base. > > This will improve debuggability by providing the correct information > to ptracer (GDB and etc). LGTM.