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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 F0E57C433E0 for ; Tue, 23 Jun 2020 21:30:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6CCA20781 for ; Tue, 23 Jun 2020 21:30:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592947831; bh=rDTaJGdmCoVcQyeluXk57ognL7Avrgnsr5Bh1IrQ7fg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AYunWV5CKdCVBK7gz05hcF6JMKBdgJosSDORINe/6PISIsV9WAKH5GJDnTIFc57s5 CVDx+wXdHxL5NkZYFjW16SwCuPU8QDbe+ogFglzWx2NBbdPCzTKLqeRLu7QO1rRL/K JdhrrJQSA/ut60lxeFgqDe4SJaGkrkpG11MWNPMc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389122AbgFWUNo (ORCPT ); Tue, 23 Jun 2020 16:13:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:55644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388077AbgFWUNc (ORCPT ); Tue, 23 Jun 2020 16:13:32 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 B235B206C3; Tue, 23 Jun 2020 20:13:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592943212; bh=rDTaJGdmCoVcQyeluXk57ognL7Avrgnsr5Bh1IrQ7fg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D+WKSjyQ6uCyDXLHLQtx4xXMajZ2WNZOaTOJNlqbaOgOE0ZTDXiP/jnYlHKV7VYJr 4ckfSaZEVHec0K5tyKP0Dmmw8LYZaPTM75aZ0ySF6oQcZVDCEMOzzfiWZdCO8tvcP9 gIZIcbl7km2pvPjBl6ZBGAufn8Pu8c9ZGwvwFSzE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christophe Leroy , Michael Ellerman , Sasha Levin Subject: [PATCH 5.7 273/477] powerpc/32s: Dont warn when mapping RO data ROX. Date: Tue, 23 Jun 2020 21:54:30 +0200 Message-Id: <20200623195420.469804463@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195407.572062007@linuxfoundation.org> References: <20200623195407.572062007@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Christophe Leroy [ Upstream commit 4b19f96a81bceaf0bcf44d79c0855c61158065ec ] Mapping RO data as ROX is not an issue since that data cannot be modified to introduce an exploit. PPC64 accepts to have RO data mapped ROX, as a trade off between kernel size and strictness of protection. On PPC32, kernel size is even more critical as amount of memory is usually small. Depending on the number of available IBATs, the last IBATs might overflow the end of text. Only warn if it crosses the end of RO data. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/6499f8eeb2a36330e5c9fc1cee9a79374875bd54.1589866984.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin --- arch/powerpc/mm/book3s32/mmu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index 39ba53ca5bb55..a9b2cbc747977 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -187,6 +187,7 @@ void mmu_mark_initmem_nx(void) int i; unsigned long base = (unsigned long)_stext - PAGE_OFFSET; unsigned long top = (unsigned long)_etext - PAGE_OFFSET; + unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET; unsigned long size; if (IS_ENABLED(CONFIG_PPC_BOOK3S_601)) @@ -201,9 +202,10 @@ void mmu_mark_initmem_nx(void) size = block_size(base, top); size = max(size, 128UL << 10); if ((top - base) > size) { - if (strict_kernel_rwx_enabled()) - pr_warn("Kernel _etext not properly aligned\n"); size <<= 1; + if (strict_kernel_rwx_enabled() && base + size > border) + pr_warn("Some RW data is getting mapped X. " + "Adjust CONFIG_DATA_SHIFT to avoid that.\n"); } setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT); base += size; -- 2.25.1