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=-2.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 64594ECDFAA for ; Wed, 18 Jul 2018 09:42:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 109C820850 for ; Wed, 18 Jul 2018 09:42:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=8bytes.org header.i=@8bytes.org header.b="cOlSHeNf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 109C820850 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org 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 S1731796AbeGRKSl (ORCPT ); Wed, 18 Jul 2018 06:18:41 -0400 Received: from 8bytes.org ([81.169.241.247]:54792 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731735AbeGRKSk (ORCPT ); Wed, 18 Jul 2018 06:18:40 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 85DAC2099; Wed, 18 Jul 2018 11:41:23 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=8bytes.org; s=mail-1; t=1531906884; bh=dfv0Zih1QJqgNawf7FbV+BW/CZ/u7bR2eHjCpA2aoNE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cOlSHeNfP/bPXkP8PlYzUEWoC32mDdwa9aHXeZHiYC8VOy16vxj4V0UzWfSgLhXcv 70qgM1w4VaMKnAYqgqTrF54Pa5wjZrV87DMz4H2OvSxJBQFzrR6/4o653KFsHa1jAE 6C4QppUSfFYh2bZbYMmctDTdzh63TOoRj5qFBLl0ktX5M8FeWOUp5N7WkLxjATqmXH DilzCmSQnTNMZfSzdfZv74HJTYSDzAsMYyh7TMoh9VwkCcIpLe2ECl6aYFAyLnGDqH wcqgXWDoFvZwiNBAHQggF2cOiVbucW1VbNVpvEM19ShttBASv1RYFZ1DwM8tN3YbuK kqRo8G+73G5Ug== From: Joerg Roedel To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , Pavel Machek , "David H . Gutteridge" , jroedel@suse.de, joro@8bytes.org Subject: [PATCH 28/39] x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text() Date: Wed, 18 Jul 2018 11:41:05 +0200 Message-Id: <1531906876-13451-29-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1531906876-13451-1-git-send-email-joro@8bytes.org> References: <1531906876-13451-1-git-send-email-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel Mapping the kernel text area to user-space makes only sense if it has the same permissions as in the kernel page-table. If permissions are different this will cause a TLB reload when using the kernel page-table, which is as good as not mapping it at all. On 64-bit kernels this patch makes no difference, as the whole range cloned by pti_clone_kernel_text() is mapped RO anyway. On 32 bit there are writeable mappings in the range, so just keep the permissions as they are. Signed-off-by: Joerg Roedel --- arch/x86/mm/pti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 4f6e933..fc77054 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -482,7 +482,7 @@ void pti_clone_kernel_text(void) * pti_set_kernel_image_nonglobal() did to clear the * global bit. */ - pti_clone_pmds(start, end, _PAGE_RW); + pti_clone_pmds(start, end, 0); } /* -- 2.7.4