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 1E8B7C433DF for ; Tue, 23 Jun 2020 20:29:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6ED9206C3 for ; Tue, 23 Jun 2020 20:29:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592944144; bh=i3jueepplDkNuk9wE4egerL1INGsMUlzWA2rMOMR2J0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tQN1olpioVkIV3FAywimROl2T+T05azNmbq3qhGqzvuxhNaPm6saqzRK95wCu6O1M fibDtpz501sOF57iDja5GgDBvDv0hwKfXK4MhjMwTmg+bO+N1vb/xIVBe1TlNuJloW EONXjV1jebq0T4loI1l4atL8xN5YdAzX/dvapUhU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389396AbgFWU3B (ORCPT ); Tue, 23 Jun 2020 16:29:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:48834 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390461AbgFWU24 (ORCPT ); Tue, 23 Jun 2020 16:28:56 -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 331D3206C3; Tue, 23 Jun 2020 20:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592944135; bh=i3jueepplDkNuk9wE4egerL1INGsMUlzWA2rMOMR2J0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MHOnciaO2F1Os8xgH1bt3frlqdvdQUGt+g82k8+x8pA8tcI5zDfhX6tSrhap0TvIt Gv1dxF0H1YJ+H3Bgs5pkpr4mVY8W4WiMFaojobPfNlT+ZyJXi1U21ypSQYGTO4xwyo Fp8pGGpxxla0CA4ZHFormbFXK0aB3Vssl+7dNT4Q= 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 5.4 186/314] powerpc/32s: Dont warn when mapping RO data ROX. Date: Tue, 23 Jun 2020 21:56:21 +0200 Message-Id: <20200623195347.776815416@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195338.770401005@linuxfoundation.org> References: <20200623195338.770401005@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 84d5fab94f8f8..1424a120710e4 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