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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 5AAC9C282D8 for ; Fri, 1 Feb 2019 20:55:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 245B8218AF for ; Fri, 1 Feb 2019 20:55:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730445AbfBAUy7 (ORCPT ); Fri, 1 Feb 2019 15:54:59 -0500 Received: from mga07.intel.com ([134.134.136.100]:49748 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730023AbfBAUy7 (ORCPT ); Fri, 1 Feb 2019 15:54:59 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Feb 2019 12:54:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,549,1539673200"; d="scan'208";a="140866366" Received: from chang-linux-2.sc.intel.com ([10.3.52.165]) by fmsmga004.fm.intel.com with ESMTP; 01 Feb 2019 12:54:58 -0800 From: "Chang S. Bae" To: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Andi Kleen Cc: Markus T Metzger , Ravi Shankar , "Chang S . Bae" , LKML Subject: [PATCH v5 07/13] x86/fsgsbase/64: When copying a thread, use the FSGSBASE instructions if available Date: Fri, 1 Feb 2019 12:53:13 -0800 Message-Id: <20190201205319.15995-9-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190201205319.15995-1-chang.seok.bae@intel.com> References: <20190201205319.15995-1-chang.seok.bae@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Copy real FS/GSBASE values instead of approximation when FSGSBASE is enabled. Factoring out to save_fsgs() does not result in the same behavior because save_base_legacy() does not copy FS/GSBASE when the index is zero. Signed-off-by: Chang S. Bae Cc: Andy Lutomirski Cc: H. Peter Anvin Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Andi Kleen --- arch/x86/kernel/process_64.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index d8ade9530fdb..648e43b58c69 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -477,10 +477,16 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, p->thread.sp = (unsigned long) fork_frame; p->thread.io_bitmap_ptr = NULL; - savesegment(gs, p->thread.gsindex); - p->thread.gsbase = p->thread.gsindex ? 0 : me->thread.gsbase; savesegment(fs, p->thread.fsindex); - p->thread.fsbase = p->thread.fsindex ? 0 : me->thread.fsbase; + savesegment(gs, p->thread.gsindex); + if (static_cpu_has(X86_FEATURE_FSGSBASE)) { + p->thread.fsbase = rdfsbase(); + p->thread.gsbase = __rdgsbase_inactive(); + } else { + /* save_base_legacy() does not set base when index is zero. */ + p->thread.fsbase = p->thread.fsindex ? 0 : me->thread.fsbase; + p->thread.gsbase = p->thread.gsindex ? 0 : me->thread.gsbase; + } savesegment(es, p->thread.es); savesegment(ds, p->thread.ds); memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); -- 2.19.1