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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6065C433EF for ; Thu, 7 Jul 2022 11:59:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235504AbiGGL7L (ORCPT ); Thu, 7 Jul 2022 07:59:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236180AbiGGL6s (ORCPT ); Thu, 7 Jul 2022 07:58:48 -0400 Received: from mail-ej1-x633.google.com (mail-ej1-x633.google.com [IPv6:2a00:1450:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31A2960520; Thu, 7 Jul 2022 04:56:28 -0700 (PDT) Received: by mail-ej1-x633.google.com with SMTP id n4so12711997ejz.10; Thu, 07 Jul 2022 04:56:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id; bh=2rCng+c6+Ic3ugn7usdk1Bb1bCGkkTmVKqnPhZXSPqk=; b=FE1lOsq1SvOf0A7puhlFa8iv0gg261tT/ojI+wPTpodjibJR7/N/37HnPQ0TJ8lu5W OfOA5oXX+8JfILRl+YzcvfbyTsolsSYGbvFxXGbImRqFyBOeaoriicR7Ac4x43PIac9L ngBNSGsSI1Iz+9QGe5wL2MLKL1wASOhlROtPkfujryvtREu+lCTurM/1IxQMzroNgNY4 T8RnNSiXBCHXGD6+KRa05dNDDYYHeM4XVvNYwpNwzxn8xfvGsCmlMyNfiOp5YgwdNqDG FT8cDqW9F9Y3u7cb8bWeTA8XiBAUmxQam/GTBlGLqqqx8vhoEuLUGvyMWYCd4VqOAvpl zAsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=2rCng+c6+Ic3ugn7usdk1Bb1bCGkkTmVKqnPhZXSPqk=; b=Y+4nufCjkB+qDOe+a2Mpo+dC4+9rn9P6VIM7DNp2snrzupjeg/E9LqKIqd4oTqL1UT BUEJNjBzmSl/86pODIhmUfaiOiUL1DG5V16RrLX5K20M0wElZUJG20aeRPR4iu1dCPxA ZiVDotjFIPCFVNWonGJvD48FROndCzCTuqFDJPtx2olRSgLYHolXuSX/rwsd+Uw7GNBQ g622Gr/YoZwrICc0w9pjQWKbLhceF2gZ3srcjjl+58YWFjfiaeVaezcmli//ENS+1LHf 38j/lZwPtBc3xzdx8192fzxNylBl9c9qKyIFF6RliX298YTKBt1yy/Sap2QrVnicJH1m 1RaQ== X-Gm-Message-State: AJIora8oIop3uiWaMO77dXKnJsVzj6/XuGZAMBaqFUXoP83Ns7Oh9FOV hGoTuncyQAJd3UTBPi5rMSnIHOuYNso= X-Google-Smtp-Source: AGRyM1t6B+Y8Zy+zmKbmWqwBGZPp/d+cPAdaYLN//Bp16hveKRBbcKnTN5OLLQqyKEAyZj/CqSIlWg== X-Received: by 2002:a17:906:4fd4:b0:722:f223:8d86 with SMTP id i20-20020a1709064fd400b00722f2238d86mr44652077ejw.558.1657194985535; Thu, 07 Jul 2022 04:56:25 -0700 (PDT) Received: from felia.fritz.box (200116b826df3d00599ec68d191c47fa.dip.versatel-1u1.de. [2001:16b8:26df:3d00:599e:c68d:191c:47fa]) by smtp.gmail.com with ESMTPSA id 21-20020a170906301500b00728f6d4d0d7sm12078708ejz.67.2022.07.07.04.56.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Jul 2022 04:56:25 -0700 (PDT) From: Lukas Bulwahn To: Dave Hansen , Kees Cook Cc: Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Lukas Bulwahn Subject: [PATCH RESEND] x86: mm: refer to the intended config STRICT_DEVMEM in a comment Date: Thu, 7 Jul 2022 13:54:42 +0200 Message-Id: <20220707115442.21107-1-lukas.bulwahn@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit a4866aa81251 ("mm: Tighten x86 /dev/mem with zeroing reads") adds a comment to the function devmem_is_allowed() referring to a non-existing config STRICT_IOMEM, whereas the comment very likely intended to refer to the config STRICT_DEVMEM, as the commit adds some behavior for the config STRICT_DEVMEM. Most of the initial analysis was actually done by Dave Hansen in the email thread below (see Link). Refer to the intended and existing config STRICT_DEVMEM. Link: https://lore.kernel.org/r/f9074e8d-9314-9d7d-7bf5-5b5538c8be8d@intel.com/ Suggested-by: Dave Hansen Signed-off-by: Lukas Bulwahn --- v1: https://lore.kernel.org/all/20211222125347.13054-1-lukas.bulwahn@gmail.com/ arch/x86/mm/init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index d8cfce221275..5d747a1923cb 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -846,7 +846,7 @@ int devmem_is_allowed(unsigned long pagenr) /* * This must follow RAM test, since System RAM is considered a - * restricted resource under CONFIG_STRICT_IOMEM. + * restricted resource under CONFIG_STRICT_DEVMEM. */ if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) { /* Low 1MB bypasses iomem restrictions. */ -- 2.17.1