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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3B214C5519A for ; Mon, 27 Apr 2020 07:49:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F403F214D8 for ; Mon, 27 Apr 2020 07:49:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="tM0MCyqE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F403F214D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8E9628E0006; Mon, 27 Apr 2020 03:49:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8BFD68E0001; Mon, 27 Apr 2020 03:49:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7FC688E0006; Mon, 27 Apr 2020 03:49:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0119.hostedemail.com [216.40.44.119]) by kanga.kvack.org (Postfix) with ESMTP id 65BAB8E0001 for ; Mon, 27 Apr 2020 03:49:23 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2CF6C8248047 for ; Mon, 27 Apr 2020 07:49:23 +0000 (UTC) X-FDA: 76752859806.21.bird34_6effc56151517 X-HE-Tag: bird34_6effc56151517 X-Filterd-Recvd-Size: 3057 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf45.hostedemail.com (Postfix) with ESMTP for ; Mon, 27 Apr 2020 07:49:22 +0000 (UTC) Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (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 8EC0B20728; Mon, 27 Apr 2020 07:49:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587973761; bh=gUEF4e+I+5LtkJ+KR7VccemOQ0DrTjrOVZmMSY/BJKo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tM0MCyqEbiKAHZFfSbvrulUKGmf63KAanMfop+yxY/F6lhWkM0zaQHm6rQTTcpbFO HOLa2VqGqzrsyLsi9beTUDK/YUbfTbFXhIaq0lXicUQ2nltnRNrmYVf2nEyZ5hYtxm L4qNVWY1RZq3IAt1JnQvY/wDdHSjRRAJ1cpgYvGY= Date: Mon, 27 Apr 2020 08:49:16 +0100 From: Will Deacon To: Zong Li Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, linux-riscv@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/4] mm: add DEBUG_WX support Message-ID: <20200427074915.GA11787@willie-the-truck> References: <23980cd0f0e5d79e24a92169116407c75bcc650d.1587455584.git.zong.li@sifive.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <23980cd0f0e5d79e24a92169116407c75bcc650d.1587455584.git.zong.li@sifive.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Apr 21, 2020 at 04:17:12PM +0800, Zong Li wrote: > Some architectures support DEBUG_WX function, it's verbatim from each > others. Extract to mm/Kconfig.debug for shared use. > > Signed-off-by: Zong Li > Suggested-by: Palmer Dabbelt > --- > mm/Kconfig.debug | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 0271b22e063f..077458ad968d 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -118,6 +118,39 @@ config DEBUG_RODATA_TEST > ---help--- > This option enables a testcase for the setting rodata read-only. > > +config ARCH_HAS_DEBUG_WX > + bool > + > +config DEBUG_WX > + bool "Warn on W+X mappings at boot" > + depends on ARCH_HAS_DEBUG_WX > + select PTDUMP_CORE > + help > + Generate a warning if any W+X mappings are found at boot. > + > + This is useful for discovering cases where the kernel is leaving > + W+X mappings after applying NX, as such mappings are a security risk. > + This check also includes UXN, which should be set on all kernel > + mappings. "UXN" is the name of a bit in the arm64 page-table descriptors, so this should be reworded now that it's in generic help text. Will