From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933485AbcI1TfD (ORCPT ); Wed, 28 Sep 2016 15:35:03 -0400 Received: from mail.kernel.org ([198.145.29.136]:36308 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932796AbcI1TeX (ORCPT ); Wed, 28 Sep 2016 15:34:23 -0400 From: Andy Lutomirski To: x86@kernel.org Cc: david@saggiorato.net, Borislav Petkov , Brian Gerst , linux-kernel@vger.kernel.org, Andy Lutomirski , stable@vger.kernel.org Subject: [PATCH 1/3] x86/init: Fix cr4_init_shadow() on CR4-less machines Date: Wed, 28 Sep 2016 12:34:14 -0700 Message-Id: <43a20f81fb504013bf613913dc25574b45336a61.1475091074.git.luto@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org cr4_init_shadow() will panic on 486-like machines without CR4. Fix it using __read_cr4_safe(). Cc: stable@vger.kernel.org Reported-by: david@saggiorato.net Fixes: 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4") Signed-off-by: Andy Lutomirski --- arch/x86/include/asm/tlbflush.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 6fa85944af83..dee8a70382ba 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -81,7 +81,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate); /* Initialize cr4 shadow for this CPU. */ static inline void cr4_init_shadow(void) { - this_cpu_write(cpu_tlbstate.cr4, __read_cr4()); + this_cpu_write(cpu_tlbstate.cr4, __read_cr4_safe()); } /* Set in this cpu's CR4. */ -- 2.7.4