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=-9.8 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,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 03B78C10F14 for ; Thu, 3 Oct 2019 17:11:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4B5620673 for ; Thu, 3 Oct 2019 17:11:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570122718; bh=jFyrjGVt0cRFDQk6Fgliyx+XUAerjBChFSMocGjBCxw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nN12ipDX1UVbH+UOfUQ3IQfpX6Lhp88Y/E4UDxoneBm8GoTDnvfP+clhujATAvHUm E0psXkt08VGnFxeqOKoJ4+GYdKe0pXiJNPPxLhIkhYGWmCvZb1MEQ8SAcjRV/xtxLa CXtOXrMz8Z1oXSFrin+YQ/u63v45wY8tuy0oHYJE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403806AbfJCQbD (ORCPT ); Thu, 3 Oct 2019 12:31:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:37568 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403790AbfJCQbA (ORCPT ); Thu, 3 Oct 2019 12:31:00 -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 9ADF12054F; Thu, 3 Oct 2019 16:30:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570120260; bh=jFyrjGVt0cRFDQk6Fgliyx+XUAerjBChFSMocGjBCxw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n3Yz1a8BZiugnHDVZHE0rszeDztU33YLZXM/oXP1CAe1AF4GSR3i0nC08Pr5FIzKl FdYJR3zsIuilOCb3matsxXapsEhu1YhdA9EkrZjvkbGZ06R56FqCSgQHxq8PRyk7eh WqdkS90kzLJshF+8AE0miV5F+k7Vma1g63Uapu8k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Catalin Marinas , James Morse , Will Deacon , Sasha Levin Subject: [PATCH 5.2 155/313] arm64: kpti: ensure patched kernel text is fetched from PoU Date: Thu, 3 Oct 2019 17:52:13 +0200 Message-Id: <20191003154548.190098694@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154533.590915454@linuxfoundation.org> References: <20191003154533.590915454@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: 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 7dbf2be470f6c..28a8f7b87ff06 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -286,6 +286,15 @@ 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