From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754059AbdKJVM5 (ORCPT <rfc822;w@1wt.eu>);
        Fri, 10 Nov 2017 16:12:57 -0500
Received: from mail.efficios.com ([167.114.142.141]:39900 "EHLO
        mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1750896AbdKJVMz (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 10 Nov 2017 16:12:55 -0500
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>, Andrew Hunter <ahh@google.com>,
        Maged Michael <maged.michael@gmail.com>, Avi Kivity <avi@scylladb.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Dave Watson <davejwatson@fb.com>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
        Andrea Parri <parri.andrea@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Greg Hackmann <ghackmann@google.com>,
        Will Deacon <will.deacon@arm.com>, David Sehr <sehr@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>, x86@kernel.org,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [RFC PATCH 0/2] x86: Fix missing core serialization on migration
Date: Fri, 10 Nov 2017 16:12:47 -0500
Message-Id: <20171110211249.10742-1-mathieu.desnoyers@efficios.com>
X-Mailer: git-send-email 2.11.0
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

x86 can return to user-space through sysexit and sysretq, which are not
core serializing. This breaks expectations from user-space about
sequential consistency from a single-threaded self-modifying program
point of view in specific migration patterns.

Feedback is welcome,

Thanks,

Mathieu

Mathieu Desnoyers (2):
  x86: Introduce sync_core_before_usermode
  Fix: x86: Add missing core serializing instruction on migration

 arch/x86/Kconfig                 |  1 +
 arch/x86/include/asm/processor.h | 10 ++++++++++
 include/linux/processor.h        |  6 ++++++
 kernel/sched/core.c              |  7 +++++++
 kernel/sched/sched.h             |  1 +
 5 files changed, 25 insertions(+)

-- 
2.11.0