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=-14.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 666F3C433E2 for ; Fri, 4 Sep 2020 13:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3911C206F2 for ; Fri, 4 Sep 2020 13:21:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="CXWxcJSw"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Lt0gZDkN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730384AbgIDNVK (ORCPT ); Fri, 4 Sep 2020 09:21:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730329AbgIDNQP (ORCPT ); Fri, 4 Sep 2020 09:16:15 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC5FDC061244; Fri, 4 Sep 2020 06:16:13 -0700 (PDT) Date: Fri, 04 Sep 2020 13:16:04 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1599225365; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FYo4oWPndmPH1VpAsfPaaX5l0/5q804nP45ekBNCsvE=; b=CXWxcJSwBfNNl7/uWWf2cFw/XH3j/xrEb7IRNn2ww5+xzVxble3MmlvuoqNg/pITFTYRx7 rvtFsmi6YkDgln7ZXjDcfLBSJD74wjgaXOmUPNPkzO3llg/wisUPXGt8NZqbke9S6+FH5V /5a/r0AAZ5K0CvkWNMXKmvruZxYxeMwudWsdDO2Gf7WIh/xWXbXJJwzHailgHrJxoabVfu 3UU3zmkhs03RnHZIkLb6SwAGVDQj6eMt/NUxSNhcs6hYPh/IT5Cf8yt/QKvOTT/U4x4C+j cZ7U6URIJKmA6DKJk0SZqoql7cFVBvbLWm5w430G5aUeZZagIRVdkPUJujRLJw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1599225365; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FYo4oWPndmPH1VpAsfPaaX5l0/5q804nP45ekBNCsvE=; b=Lt0gZDkN5FP0WS3HroUN40FXymZBsCp+UjC0KJvIQLtU5U4ejFHdHUSn5/HTuv5NY26KyG 0DyRfiQqmSjo3yCg== From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/entry: Fix AC assertion Cc: "Peter Zijlstra (Intel)" , Thomas Gleixner , Daniel Thompson , Andy Lutomirski , stable@vger.kernel.org, x86 , LKML In-Reply-To: <20200902133200.666781610@infradead.org> References: <20200902133200.666781610@infradead.org> MIME-Version: 1.0 Message-ID: <159922536478.20229.11152935257298904584.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 662a0221893a3d58aa72719671844264306f6e4b Gitweb: https://git.kernel.org/tip/662a0221893a3d58aa72719671844264306f6e4b Author: Peter Zijlstra AuthorDate: Wed, 02 Sep 2020 15:25:50 +02:00 Committer: Thomas Gleixner CommitterDate: Fri, 04 Sep 2020 15:09:29 +02:00 x86/entry: Fix AC assertion The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") unconditionally triggers on a IVB machine because it does not support SMAP. For !SMAP hardware the CLAC/STAC instructions are patched out and thus if userspace sets AC, it is still have set after entry. Fixes: 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Tested-by: Daniel Thompson Acked-by: Andy Lutomirski Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200902133200.666781610@infradead.org --- arch/x86/include/asm/entry-common.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h index a8f9315..6fe54b2 100644 --- a/arch/x86/include/asm/entry-common.h +++ b/arch/x86/include/asm/entry-common.h @@ -18,8 +18,16 @@ static __always_inline void arch_check_user_regs(struct pt_regs *regs) * state, not the interrupt state as imagined by Xen. */ unsigned long flags = native_save_fl(); - WARN_ON_ONCE(flags & (X86_EFLAGS_AC | X86_EFLAGS_DF | - X86_EFLAGS_NT)); + unsigned long mask = X86_EFLAGS_DF | X86_EFLAGS_NT; + + /* + * For !SMAP hardware we patch out CLAC on entry. + */ + if (boot_cpu_has(X86_FEATURE_SMAP) || + (IS_ENABLED(CONFIG_64_BIT) && boot_cpu_has(X86_FEATURE_XENPV))) + mask |= X86_EFLAGS_AC; + + WARN_ON_ONCE(flags & mask); /* We think we came from user mode. Make sure pt_regs agrees. */ WARN_ON_ONCE(!user_mode(regs));