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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 20879C2B9F4 for ; Tue, 22 Jun 2021 22:25:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 01AE76113E for ; Tue, 22 Jun 2021 22:25:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230403AbhFVW2G (ORCPT ); Tue, 22 Jun 2021 18:28:06 -0400 Received: from mga04.intel.com ([192.55.52.120]:42834 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230013AbhFVW2A (ORCPT ); Tue, 22 Jun 2021 18:28:00 -0400 IronPort-SDR: Mjd6RI1Z939a88c7zpL0wVqiTZT2Ltkbn1DpDpE51qhC22sUMR1awEHYdw1NZMM6Ykh+b4AmAl 0GrjmKUesj7Q== X-IronPort-AV: E=McAfee;i="6200,9189,10023"; a="205326073" X-IronPort-AV: E=Sophos;i="5.83,292,1616482800"; d="scan'208";a="205326073" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2021 15:25:44 -0700 IronPort-SDR: l/2YXcZIURD4o4Mz8p7B9GgFYO6mzupeXtmpv8/Lii3Yi7ndbLUqPRyV4pM9pjUFP/Z5jhG50m 6atJVNRTCPfQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.83,292,1616482800"; d="scan'208";a="444756931" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga007.jf.intel.com with ESMTP; 22 Jun 2021 15:25:43 -0700 Subject: [RFC][PATCH 2/8] x86/fpu: hook up PKRU into signal user ABIs To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Dave Hansen , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, luto@kernel.org From: Dave Hansen Date: Tue, 22 Jun 2021 15:24:59 -0700 References: <20210622222455.E901B5AC@viggo.jf.intel.com> In-Reply-To: <20210622222455.E901B5AC@viggo.jf.intel.com> Message-Id: <20210622222459.9C76B034@viggo.jf.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen One nice thing about having PKRU be XSAVE-managed is that it gets naturally exposed into the XSAVE-using ABIs. Now that XSAVE will not be used to manage PKRU, these ABIs need to be manually enabled to deal with PKRU. For signals (the restore_hwregs_from_user() path), it's quite straightforward. restore_hwregs_from_user() will update PKRU in from the user signal buffer. Ensure that PKRU is shuffled into the thread storage. Signed-off-by: Dave Hansen Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: x86@kernel.org Cc: Andy Lutomirski --- b/arch/x86/kernel/fpu/signal.c | 7 +++++++ 1 file changed, 7 insertions(+) diff -puN arch/x86/kernel/fpu/signal.c~fpu-sig-stash-pkru arch/x86/kernel/fpu/signal.c --- a/arch/x86/kernel/fpu/signal.c~fpu-sig-stash-pkru 2021-06-22 14:49:07.899051760 -0700 +++ b/arch/x86/kernel/fpu/signal.c 2021-06-22 14:49:07.903051760 -0700 @@ -233,6 +233,13 @@ static int restore_hwregs_from_user(void if (!ret && unlikely(init_bv)) os_xrstor(&init_fpstate.xsave, init_bv); + + /* + * PKRU may have been modified by XRSTOR, + * save the possibly updated value: + */ + current->thread.pkru = read_pkru(); + return ret; } else if (use_fxsr()) { return fxrstor_from_user_sigframe(buf); _