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=-7.8 required=3.0 tests=DATE_IN_PAST_06_12, 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 EAB48C04AAB for ; Wed, 8 May 2019 17:04:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7EB4216F4 for ; Wed, 8 May 2019 17:04:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729142AbfEHRED (ORCPT ); Wed, 8 May 2019 13:04:03 -0400 Received: from mga03.intel.com ([134.134.136.65]:5321 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728972AbfEHRDF (ORCPT ); Wed, 8 May 2019 13:03:05 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 May 2019 10:03:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,446,1549958400"; d="scan'208";a="169697576" Received: from chang-linux-3.sc.intel.com ([172.25.66.171]) by fmsmga002.fm.intel.com with ESMTP; 08 May 2019 10:03:03 -0700 From: "Chang S. Bae" To: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Andi Kleen Cc: Ravi Shankar , "Chang S . Bae" , LKML , Dave Hansen Subject: [PATCH v7 09/18] x86/entry/64: Add the READ_MSR_GSBASE macro Date: Wed, 8 May 2019 03:02:24 -0700 Message-Id: <1557309753-24073-10-git-send-email-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1557309753-24073-1-git-send-email-chang.seok.bae@intel.com> References: <1557309753-24073-1-git-send-email-chang.seok.bae@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Factor out the RDMSR-based GSBASE read into a new macro. Signed-off-by: Chang S. Bae Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Andy Lutomirski Cc: H. Peter Anvin Cc: Andi Kleen Cc: Dave Hansen --- arch/x86/entry/calling.h | 9 +++++++++ arch/x86/entry/entry_64.S | 12 ++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index efb0d1b..d119729 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -337,6 +337,15 @@ For 32-bit we have the following conventions - kernel is built with #endif .endm +.macro READ_MSR_GSBASE save_reg:req + movl $MSR_GS_BASE, %ecx + /* Read MSR specified by %ecx into %edx:%eax */ + rdmsr + .ifnc \save_reg, %edx + movl %edx, \save_reg + .endif +.endm + #endif /* CONFIG_X86_64 */ .macro STACKLEAK_ERASE diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 20e45d9..568a491 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1159,11 +1159,15 @@ ENTRY(paranoid_entry) cld PUSH_AND_CLEAR_REGS save_ret=1 ENCODE_FRAME_POINTER 8 + movl $1, %ebx - movl $MSR_GS_BASE, %ecx - rdmsr - testl %edx, %edx - js 1f /* negative -> in kernel */ + /* + * The kernel-enforced convention is a negative GSBASE indicates + * a kernel value. + */ + READ_MSR_GSBASE save_reg=%edx + testl %edx, %edx /* Negative -> in kernel */ + js 1f SWAPGS xorl %ebx, %ebx -- 2.7.4