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 D43F8C3A5A2 for ; Sun, 22 Sep 2019 19:16:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A36C120869 for ; Sun, 22 Sep 2019 19:16:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569179760; bh=ta+KEqzYSHy/qTopfT8NAaQJ7lpEpvgFviApnhGf4yc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jrMLJC17/M4/4HyHZHphDjoJdl7VD4d2o/D0uGJ2f+eVicQMEuL/CTns6o8Osors+ u6JVrvz8pF+v8BQ4uA1eEJ5577WEt8U+3gSNjqexY7Z6WXfiKovP2jx+jHnoPc07SW ELdDLL+fsTJi9uRo6aUIOzFuZehpP0vIDKKGtauc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436994AbfIVTQA (ORCPT ); Sun, 22 Sep 2019 15:16:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:58276 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394574AbfIVS4S (ORCPT ); Sun, 22 Sep 2019 14:56:18 -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 616222184D; Sun, 22 Sep 2019 18:56:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569178578; bh=ta+KEqzYSHy/qTopfT8NAaQJ7lpEpvgFviApnhGf4yc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OTwDxWWDKUl8XPb0rwamFBz/ESTszqfz2pyb3uy8z3m9ieL3n069Xk2k+TFbsMMu+ KhFXtxCrsCGbnOnyE7L3TEkPDvq+6WpdOkBqtLugf4MeSWICSHe+T/T7jrm1p4slcc thRgY3yZMG3UiJBLfstYOD0FOS+LurcV74M9fCmE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Thomas Gleixner , Dave Hansen , Ingo Molnar , Song Liu , Peter Zijlstra , Sasha Levin Subject: [PATCH AUTOSEL 4.19 088/128] x86/mm/pti: Do not invoke PTI functions when PTI is disabled Date: Sun, 22 Sep 2019 14:53:38 -0400 Message-Id: <20190922185418.2158-88-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: 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