Received: by 2002:ac0:946b:0:0:0:0:0 with SMTP id j40csp2717810imj; Mon, 11 Feb 2019 07:26:53 -0800 (PST) X-Google-Smtp-Source: AHgI3Ib6dDRmY1dOeCD2c7fEwEQ/UIJNeJd5KIeIb41hCJzSYkaF0o+S9T1rBiu4bLOGVV16xW25 X-Received: by 2002:a63:cf54:: with SMTP id b20mr19847110pgj.123.1549898813605; Mon, 11 Feb 2019 07:26:53 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1549898813; cv=none; d=google.com; s=arc-20160816; b=r9xM3PeiJEsA7uFYeuWq3Dw4FJqL48G86f1tJGaUIv8HibIXJFxnsdyJOo3njghVZm 3Vvm76WihH3eWjbqOYaZ8lH9i5C2TOvjFRm6k2aFWB5RKkNUW2tbn2Q7dokXy9XXbqHq IhegXnUblSLJ0nSuUA1lNkAO2pNqqGOJE3cYc1qfh1oI2mT6JH/CUCJlP1MpE2oI1o3d BNg/CwjGrwPnPeXLKjGea7eeZCeLEkvOTwNMvNmCZ6xWrCMMN9idKOCSB+mQdrBvtv36 yq7ZPgMk7ckoX0MELderx/OE3wV2sJAUDBhR5xHyzK0FCYUZ2nYDi/lPoA5u0D6hqWjn 2COA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=4hojkixuov+YNZ+g9iPZ42qxS1vp6Y4LLVLTNRC/48Y=; b=yLCcWjswvcQs32crmxoX/TYTrskmt5ohnpL4pmyTz4FnloypYH7DK+7sCzouaQyGk6 fR4BvTP2jEvHZclGiY3N6zM9Z0M8Jv88eqXAbwJ6ZBNvM/cVaKN0TzIwlZC351PfDb0k jRE4inbzyNuuM0X4J8NOa11vdN2GmLXzLsMqHucBrnCxYDUmqiNmxTQBv49Sr/pnd9tq K8TKdnsUEPfbQCCXzkX8WmnCOByC6vnrIUxGvIuq8GxlOJynQH9nQjqcsewPDcLZF2lA xhi/3S9cudWrLZW8terVQAb1Sr99twfrRkeF/IOUZUTALo73MHXx4KAoKolllcHUIaPw 8WAw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=u46jTm7r; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id m5si11000719pfm.149.2019.02.11.07.26.37; Mon, 11 Feb 2019 07:26:53 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=u46jTm7r; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390113AbfBKPBF (ORCPT + 99 others); Mon, 11 Feb 2019 10:01:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:49006 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390097AbfBKPBD (ORCPT ); Mon, 11 Feb 2019 10:01:03 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 20F5A222A7; Mon, 11 Feb 2019 15:01:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549897262; bh=gPmJKA67Ch26ua1Pp3F+3LHqTv1tS85PVDPrISh5BtA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u46jTm7r+s80rfwsFPegg2plA5sbsvadJv3kuNhnHuhCYmCFVWCgPB4Y3AUbs7EYn nO0/+oQpcZ83EJWTs+t6s3M7Ngj6gBXRRMUYmgapTaKKBhhWRASqjroz0TokQS4ZlJ e8bi8bN1VyW08+9NRjKN077T6vz411qzJG5bFWdw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anton Ivanov , Richard Weinberger , Sasha Levin Subject: [PATCH 4.14 143/205] um: Avoid marking pages with "changed protection" Date: Mon, 11 Feb 2019 15:19:01 +0100 Message-Id: <20190211141837.720534756@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141827.214852402@linuxfoundation.org> References: <20190211141827.214852402@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 8892d8545f2d0342b9c550defbfb165db237044b ] Changing protection is a very high cost operation in UML because in addition to an extra syscall it also interrupts mmap merge sequences generated by the tlb. While the condition is not particularly common it is worth avoiding. Signed-off-by: Anton Ivanov Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/include/asm/pgtable.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h index 7485398d0737..9c04562310b3 100644 --- a/arch/um/include/asm/pgtable.h +++ b/arch/um/include/asm/pgtable.h @@ -197,12 +197,17 @@ static inline pte_t pte_mkold(pte_t pte) static inline pte_t pte_wrprotect(pte_t pte) { - pte_clear_bits(pte, _PAGE_RW); + if (likely(pte_get_bits(pte, _PAGE_RW))) + pte_clear_bits(pte, _PAGE_RW); + else + return pte; return(pte_mknewprot(pte)); } static inline pte_t pte_mkread(pte_t pte) { + if (unlikely(pte_get_bits(pte, _PAGE_USER))) + return pte; pte_set_bits(pte, _PAGE_USER); return(pte_mknewprot(pte)); } @@ -221,6 +226,8 @@ static inline pte_t pte_mkyoung(pte_t pte) static inline pte_t pte_mkwrite(pte_t pte) { + if (unlikely(pte_get_bits(pte, _PAGE_RW))) + return pte; pte_set_bits(pte, _PAGE_RW); return(pte_mknewprot(pte)); } -- 2.19.1