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 854E4C4CED1 for ; Thu, 3 Oct 2019 16:19:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D45D22459 for ; Thu, 3 Oct 2019 16:19:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570119572; bh=ta+KEqzYSHy/qTopfT8NAaQJ7lpEpvgFviApnhGf4yc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=a8j4tG1AvABte+BAtDJw1d1Ln/LDRVdGDWoBVKXLe5v3DTBFjVAca1BE/CI6fYeM7 K9z9moQ0uJBmUoDXNvuV0ru5SXlszWvVsHgzfwsuLZcPZoo3GSwnKTfr5MYTUYcbb/ BzYYWw6y4yXZY20WklKqJRyVkP0UYS9YsaRZHzgU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389491AbfJCQTb (ORCPT ); Thu, 3 Oct 2019 12:19:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:46496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388246AbfJCQT1 (ORCPT ); Thu, 3 Oct 2019 12:19:27 -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 D2144222BE; Thu, 3 Oct 2019 16:19:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570119566; bh=ta+KEqzYSHy/qTopfT8NAaQJ7lpEpvgFviApnhGf4yc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ODKimWk/ICOv7RyNGPn3vuFy00hO7ZYg8z5WPCeBn+1sQXhwQ66a3PdFIXfv8Ygdo /ZpqABZYzK/Epp5kCwSnA2Q2tbwuG5Dxfv18sam95EHnR9qJByzjTrkZhoYLMFoYDy TBcgVwTyr+VWBV/ZEStUGdfQ11SeT2i64C7ewL08= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Dave Hansen , Ingo Molnar , Song Liu , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 4.19 110/211] x86/mm/pti: Do not invoke PTI functions when PTI is disabled Date: Thu, 3 Oct 2019 17:52:56 +0200 Message-Id: <20191003154512.509163128@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154447.010950442@linuxfoundation.org> References: <20191003154447.010950442@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Thomas Gleixner [ Upstream commit 990784b57731192b7d90c8d4049e6318d81e887d ] When PTI is disabled at boot time either because the CPU is not affected or PTI has been disabled on the command line, the boot code still calls into pti_finalize() which then unconditionally invokes: pti_clone_entry_text() pti_clone_kernel_text() pti_clone_kernel_text() was called unconditionally before the 32bit support was added and 32bit added the call to pti_clone_entry_text(). The call has no side effects as cloning the page tables into the available second one, which was allocated for PTI does not create damage. But it does not make sense either and in case that this functionality would be extended later this might actually lead to hard to diagnose issues. Neither function should be called when PTI is runtime disabled. Make the invocation conditional. Signed-off-by: Thomas Gleixner Reviewed-by: Dave Hansen Acked-by: Ingo Molnar Acked-by: Song Liu Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20190828143124.063353972@linutronix.de Signed-off-by: Sasha Levin --- arch/x86/mm/pti.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 4df3e5c89d57c..c1ba376484a5b 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -643,6 +643,8 @@ void __init pti_init(void) */ void pti_finalize(void) { + if (!boot_cpu_has(X86_FEATURE_PTI)) + return; /* * We need to clone everything (again) that maps parts of the * kernel image. -- 2.20.1