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=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 1AACFC2D0A3 for ; Mon, 9 Nov 2020 14:45:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B38002074F for ; Mon, 9 Nov 2020 14:45:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="BuEbm6ff" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731671AbgKIOp5 (ORCPT ); Mon, 9 Nov 2020 09:45:57 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:37030 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730649AbgKIOp4 (ORCPT ); Mon, 9 Nov 2020 09:45:56 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0A9EjPvD109037; Mon, 9 Nov 2020 14:45:35 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=e3RqeI34JI/cQCUfvJ7qYay9adrF4lZ/AYIFC9PXrJE=; b=BuEbm6ffyyv6wojUVpg1h0pxofb6mI2MZFsPsPjRlWSs+7PGZ2Dr3tuDtU55G82/U2NL RUl7lqSwmS0pe7k2qvzyOK5BjC9gneRD3lM4Dkol0ynQyObPLcSGj4cMbGAxKl9mJ98e mPG8ArPJyCj7WneZtSM43Od/1mxF+NatSWMhqfablkPZGnGl+EM6YQ98Hn7nZKzBwPW4 STwYhSWt/L61r+n+SmlRgmfDc4s8Xvdchq+9ql2mqWVX3cbx3i+/aE7ZuLSSNLCoCAb5 +HbQ8gujfkHU2Qkqt8/IMwzCt9UOaChDoU2E88jfiehSnz9tfdnqERFPXgRKN4bf0r87 zw== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 34p72ecee9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 09 Nov 2020 14:45:35 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0A9Ef1UC138984; Mon, 9 Nov 2020 14:43:35 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 34p5bqkb4g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 09 Nov 2020 14:43:35 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0A9EhYaX013648; Mon, 9 Nov 2020 14:43:34 GMT Received: from linux.nl.oracle.com (/10.175.27.128) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 09 Nov 2020 06:43:33 -0800 From: Alexandre Chartre To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, thomas.lendacky@amd.com, jroedel@suse.de Cc: konrad.wilk@oracle.com, jan.setjeeilers@oracle.com, junaids@google.com, oweisse@google.com, rppt@linux.vnet.ibm.com, graf@amazon.de, mgross@linux.intel.com, kuzuno@gmail.com, alexandre.chartre@oracle.com Subject: [RFC][PATCH 18/24] x86/pti: Execute system vector handlers on the kernel stack Date: Mon, 9 Nov 2020 15:44:19 +0100 Message-Id: <20201109144425.270789-19-alexandre.chartre@oracle.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20201109144425.270789-1-alexandre.chartre@oracle.com> References: <20201109144425.270789-1-alexandre.chartre@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9799 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 malwarescore=0 phishscore=0 spamscore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011090103 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9799 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxlogscore=999 mlxscore=0 malwarescore=0 suspectscore=0 lowpriorityscore=0 adultscore=0 phishscore=0 priorityscore=1501 spamscore=0 impostorscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011090103 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After an interrupt/exception in userland, the kernel is entered and it switches the stack to the PTI stack which is mapped both in the kernel and in the user page-table. When executing the interrupt function, switch to the kernel stack (which is mapped only in the kernel page-table) so that no kernel data leak to the userland through the stack. Changes system vector handlers to execute on the kernel stack. Signed-off-by: Alexandre Chartre --- arch/x86/include/asm/idtentry.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index a82e31b45442..0c5d9f027112 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -66,6 +66,17 @@ void run_idt_errcode(void (*func)(struct pt_regs *, unsigned long), CALL_ON_STACK_2(pti_kernel_stack(regs), func, regs, error_code); } +static __always_inline +void run_sysvec(void (*func)(struct pt_regs *regs), struct pt_regs *regs) +{ + void *stack = pti_kernel_stack(regs); + + if (stack) + asm_call_on_stack_1(stack, (void (*)(void))func, regs); + else + run_sysvec_on_irqstack_cond(func, regs); +} + /** * DECLARE_IDTENTRY - Declare functions for simple IDT entry points * No error code pushed by hardware @@ -295,7 +306,7 @@ __visible noinstr void func(struct pt_regs *regs) \ instrumentation_begin(); \ irq_enter_rcu(); \ kvm_set_cpu_l1tf_flush_l1d(); \ - run_sysvec_on_irqstack_cond(__##func, regs); \ + run_sysvec(__##func, regs); \ irq_exit_rcu(); \ instrumentation_end(); \ irqentry_exit(regs, state); \ -- 2.18.4