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=-10.1 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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 32A5CC3A5A2 for ; Sun, 22 Sep 2019 19:16:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F367120869 for ; Sun, 22 Sep 2019 19:16:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569179768; bh=URUZzsuEtvmqgS69CvYyDYYGVRNJ0Jzif+eoUQ1PBvo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DztsJFbqSrgxsDnsS428HoedGIhn4MTQlG3mMJ+uXgZ8IrSZuLjJFkCL9LovxSdru b04W6FKYoU7i6K49bUH1lmEqsVpkPZfmwn5IqYeej5YU0fRptBk05rPAZZPCarMxJo +90NQeTLEsfn9BU86mPHJMT33+vpeyc4RWuebm9w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395527AbfIVTQG (ORCPT ); Sun, 22 Sep 2019 15:16:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:58250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391327AbfIVS4R (ORCPT ); Sun, 22 Sep 2019 14:56:17 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 15E4B2186A; Sun, 22 Sep 2019 18:56:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569178576; bh=URUZzsuEtvmqgS69CvYyDYYGVRNJ0Jzif+eoUQ1PBvo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I9KmqqrrKHOREFwViGGxz3d+YTu9E6Mhp3QOCi/CI9pSy7k8qdykA0FMxym/26rbh yOce+Ag8dJ66N32dx8IP2N8U/pxKOiO6N2MNMeGcEzYYZGc5qKYDGuyqzgc0I9Rqb6 NOg1KUfOxtE3oaCFLiiFzo+OkPPkPJShZ8n2thHc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mark Rutland , Catalin Marinas , James Morse , Will Deacon , Sasha Levin Subject: [PATCH AUTOSEL 4.19 087/128] arm64: kpti: ensure patched kernel text is fetched from PoU Date: Sun, 22 Sep 2019 14:53:37 -0400 Message-Id: <20190922185418.2158-87-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190922185418.2158-1-sashal@kernel.org> References: <20190922185418.2158-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Rutland [ Upstream commit f32c7a8e45105bd0af76872bf6eef0438ff12fb2 ] While the MMUs is disabled, I-cache speculation can result in instructions being fetched from the PoC. During boot we may patch instructions (e.g. for alternatives and jump labels), and these may be dirty at the PoU (and stale at the PoC). Thus, while the MMU is disabled in the KPTI pagetable fixup code we may load stale instructions into the I-cache, potentially leading to subsequent crashes when executing regions of code which have been modified at runtime. Similarly to commit: 8ec41987436d566f ("arm64: mm: ensure patched kernel text is fetched from PoU") ... we can invalidate the I-cache after enabling the MMU to prevent such issues. The KPTI pagetable fixup code itself should be clean to the PoC per the boot protocol, so no maintenance is required for this code. Signed-off-by: Mark Rutland Cc: Catalin Marinas Reviewed-by: James Morse Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/mm/proc.S | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 8cce091b6c21e..ec6aa18633162 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -294,6 +294,15 @@ skip_pgd: msr sctlr_el1, x18 isb + /* + * Invalidate the local I-cache so that any instructions fetched + * speculatively from the PoC are discarded, since they may have + * been dynamically patched at the PoU. + */ + ic iallu + dsb nsh + isb + /* Set the flag to zero to indicate that we're all done */ str wzr, [flag_ptr] ret -- 2.20.1