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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 377EFECDFB8 for ; Thu, 19 Jul 2018 23:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E3F3120684 for ; Thu, 19 Jul 2018 23:33:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E3F3120684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731361AbeGTASc (ORCPT ); Thu, 19 Jul 2018 20:18:32 -0400 Received: from terminus.zytor.com ([198.137.202.136]:49277 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727743AbeGTASb (ORCPT ); Thu, 19 Jul 2018 20:18:31 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w6JNWA8K2453904 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 19 Jul 2018 16:32:10 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w6JNWAMc2453901; Thu, 19 Jul 2018 16:32:10 -0700 Date: Thu, 19 Jul 2018 16:32:10 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Joerg Roedel Message-ID: Cc: aarcange@redhat.com, peterz@infradead.org, gregkh@linuxfoundation.org, dvlasenk@redhat.com, tglx@linutronix.de, hpa@zytor.com, llong@redhat.com, dave.hansen@intel.com, torvalds@linux-foundation.org, jpoimboe@redhat.com, eduval@amazon.com, mingo@kernel.org, brgerst@gmail.com, luto@kernel.org, jgross@suse.com, boris.ostrovsky@oracle.com, bp@alien8.de, will.deacon@arm.com, linux-kernel@vger.kernel.org, dhgutteridge@sympatico.ca, David.Laight@aculab.com, jroedel@suse.de, jkosina@suse.cz, pavel@ucw.cz Reply-To: brgerst@gmail.com, luto@kernel.org, bp@alien8.de, jgross@suse.com, boris.ostrovsky@oracle.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, David.Laight@aculab.com, dhgutteridge@sympatico.ca, jkosina@suse.cz, jroedel@suse.de, pavel@ucw.cz, aarcange@redhat.com, peterz@infradead.org, gregkh@linuxfoundation.org, dvlasenk@redhat.com, hpa@zytor.com, tglx@linutronix.de, torvalds@linux-foundation.org, llong@redhat.com, dave.hansen@intel.com, jpoimboe@redhat.com, eduval@amazon.com, mingo@kernel.org In-Reply-To: <1531906876-13451-27-git-send-email-joro@8bytes.org> References: <1531906876-13451-27-git-send-email-joro@8bytes.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level on x86_32 Git-Commit-ID: f94560cd6b5117f8913f4c42f4d9a405c26ddc1c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f94560cd6b5117f8913f4c42f4d9a405c26ddc1c Gitweb: https://git.kernel.org/tip/f94560cd6b5117f8913f4c42f4d9a405c26ddc1c Author: Joerg Roedel AuthorDate: Wed, 18 Jul 2018 11:41:03 +0200 Committer: Thomas Gleixner CommitDate: Fri, 20 Jul 2018 01:11:44 +0200 x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level on x86_32 Cloning on the P4D level would clone the complete kernel address space into the user-space page-tables for PAE kernels. Cloning on PMD level is fine for PAE and legacy paging. Signed-off-by: Joerg Roedel Signed-off-by: Thomas Gleixner Tested-by: Pavel Machek Cc: "H . Peter Anvin" Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Dave Hansen Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Jiri Kosina Cc: Boris Ostrovsky Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: Andrea Arcangeli Cc: Waiman Long Cc: "David H . Gutteridge" Cc: joro@8bytes.org Link: https://lkml.kernel.org/r/1531906876-13451-27-git-send-email-joro@8bytes.org --- arch/x86/mm/pti.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 79217868dd13..a594e3b6401a 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -348,6 +348,7 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear) } } +#ifdef CONFIG_X86_64 /* * Clone a single p4d (i.e. a top-level entry on 4-level systems and a * next-level entry on 5-level systems. @@ -371,6 +372,25 @@ static void __init pti_clone_user_shared(void) pti_clone_p4d(CPU_ENTRY_AREA_BASE); } +#else /* CONFIG_X86_64 */ + +/* + * On 32 bit PAE systems with 1GB of Kernel address space there is only + * one pgd/p4d for the whole kernel. Cloning that would map the whole + * address space into the user page-tables, making PTI useless. So clone + * the page-table on the PMD level to prevent that. + */ +static void __init pti_clone_user_shared(void) +{ + unsigned long start, end; + + start = CPU_ENTRY_AREA_BASE; + end = start + (PAGE_SIZE * CPU_ENTRY_AREA_PAGES); + + pti_clone_pmds(start, end, 0); +} +#endif /* CONFIG_X86_64 */ + /* * Clone the ESPFIX P4D into the user space visible page table */