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 217F3C32792 for ; Thu, 3 Oct 2019 17:00:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE2DC20673 for ; Thu, 3 Oct 2019 17:00:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570122020; bh=2et6kh5u9FLYVe88GeLbMKtsoeoF/CZr/Ah6IeVbid4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RpCTELNqgXiK+8gTH37kcgxK1nnp8IXnVTbuEklYyjbiJG8FYrvMwyY25ffpVdgub YprdoAgmDAU8YQtv5oNkCZKaPPpPPS7TNMdv8CPTrzPLUMks6TjRmOBHzfTvBvIOfg ni9oqGBH2IGbxJnhDyqXOlIQZx1F3/zojQWFdt0o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393158AbfJCRAT (ORCPT ); Thu, 3 Oct 2019 13:00:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:58922 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732998AbfJCQqA (ORCPT ); Thu, 3 Oct 2019 12:46:00 -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 3AC352133F; Thu, 3 Oct 2019 16:45:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570121159; bh=2et6kh5u9FLYVe88GeLbMKtsoeoF/CZr/Ah6IeVbid4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DxNV7lDOMbExO53fnCGQcOZutwyxgZHW9Ir3HolFdgaza+UHBIX/4r5A+83r7uKIz m5mHm/blsVMncJEN8qELq1b0POGz349xvhhOg9k+nzzp4oQ86Onake5fryC7pMiabE ZAD5O3S6YHA53SQnR/Q0uNSv/rEkDoUupHMUUQfU= 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 5.3 175/344] x86/mm/pti: Do not invoke PTI functions when PTI is disabled Date: Thu, 3 Oct 2019 17:52:20 +0200 Message-Id: <20191003154557.501455396@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154540.062170222@linuxfoundation.org> References: <20191003154540.062170222@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: 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 b196524759ec5..ba22b50f4eca2 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -666,6 +666,8 @@ 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