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=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 E1C51C43461 for ; Tue, 8 Sep 2020 19:23:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A19632087D for ; Tue, 8 Sep 2020 19:23:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599592986; bh=G3yYAauvg1nc0U6RbIDLTD7OSZHU2kfssKheN+EhsM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=waJYBO6M5/TeO6Q/P1V4OJEEJVFscOlyjILMmQ9b/J7HxQez6ycwNT/Oxm76YGA2C b+ia9xNPW1aO1a0oSKfNtOO+Q4YIiNduxvz+BK6+WN5xcFF41cipbdqAEJwKEp9dXh 7IAiaGJbHSb7Sq3woLd3ScKxBqAVW2901NNSlxmQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732120AbgIHTXF (ORCPT ); Tue, 8 Sep 2020 15:23:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:47736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731030AbgIHQBb (ORCPT ); Tue, 8 Sep 2020 12:01:31 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 3194F241A4; Tue, 8 Sep 2020 15:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599579536; bh=G3yYAauvg1nc0U6RbIDLTD7OSZHU2kfssKheN+EhsM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JoHLGhELAqmeaKJEyJJhiDhLxBWoHnqb9wwRFk2lrZUusYOGTYmU5cZSEjOMdJQxt 7lEwtV88hVbqa4RtbbutUkmy1JY76p6coUawbfSdVQAxLxm/V97hDluYPgl/PG3ZH+ l7RLnsWlGIDZOl7N790ULSsAdsySSkHToUYSxvo4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Thomas Gleixner , Daniel Thompson , Andy Lutomirski Subject: [PATCH 5.8 119/186] x86/entry: Fix AC assertion Date: Tue, 8 Sep 2020 17:24:21 +0200 Message-Id: <20200908152247.404223856@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152241.646390211@linuxfoundation.org> References: <20200908152241.646390211@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: Peter Zijlstra commit 662a0221893a3d58aa72719671844264306f6e4b upstream. 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/common.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -55,8 +55,16 @@ static noinstr void check_user_regs(stru * 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));