Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755990AbcJNM5p (ORCPT ); Fri, 14 Oct 2016 08:57:45 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:42205 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755420AbcJNM4Z (ORCPT ); Fri, 14 Oct 2016 08:56:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dave Hansen , Dave Hansen , Thomas Gleixner Subject: [PATCH 4.7 21/31] x86/pkeys: Make protection keys an "eager" feature Date: Fri, 14 Oct 2016 14:55:05 +0200 Message-Id: <20161014122716.113043886@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161014122715.235592611@linuxfoundation.org> References: <20161014122715.235592611@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2140 Lines: 55 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Hansen commit d4b05923f579c234137317cdf9a5eb69ddab76d1 upstream. Our XSAVE features are divided into two categories: those that generate FPU exceptions, and those that do not. MPX and pkeys do not generate FPU exceptions and thus can not be used lazily. We disable them when lazy mode is forced on. We have a pair of masks to collect these two sets of features, but XFEATURE_MASK_PKRU was added to the wrong mask: XFEATURE_MASK_LAZY. Fix it by moving the feature to XFEATURE_MASK_EAGER. Note: this only causes problem if you boot with lazy FPU mode (eagerfpu=off) which is *not* the default. It also only affects hardware which is not currently publicly available. It looks like eager mode is going away, but we still need this patch applied to any kernel that has protection keys and lazy mode, which is 4.6 through 4.8 at this point, and 4.9 if the lazy removal isn't sent to Linus for 4.9. Fixes: c8df40098451 ("x86/fpu, x86/mm/pkeys: Add PKRU xsave fields and data structures") Signed-off-by: Dave Hansen Cc: Dave Hansen Link: http://lkml.kernel.org/r/20161007162342.28A49813@viggo.jf.intel.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/fpu/xstate.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -24,11 +24,12 @@ XFEATURE_MASK_YMM | \ XFEATURE_MASK_OPMASK | \ XFEATURE_MASK_ZMM_Hi256 | \ - XFEATURE_MASK_Hi16_ZMM | \ - XFEATURE_MASK_PKRU) + XFEATURE_MASK_Hi16_ZMM) /* Supported features which require eager state saving */ -#define XFEATURE_MASK_EAGER (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR) +#define XFEATURE_MASK_EAGER (XFEATURE_MASK_BNDREGS | \ + XFEATURE_MASK_BNDCSR | \ + XFEATURE_MASK_PKRU) /* All currently supported features */ #define XCNTXT_MASK (XFEATURE_MASK_LAZY | XFEATURE_MASK_EAGER)