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=-12.8 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 2D70DC64E69 for ; Mon, 16 Nov 2020 14:48:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E8C8F223FB for ; Mon, 16 Nov 2020 14:48:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="k+wrcO9b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730506AbgKPOrl (ORCPT ); Mon, 16 Nov 2020 09:47:41 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:56324 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730396AbgKPOri (ORCPT ); Mon, 16 Nov 2020 09:47:38 -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 0AGEjhNV034338; Mon, 16 Nov 2020 14:47:19 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=k+wrcO9b1m0VI/XL0sJjVzw419pLUdtm4i4o6pWBFfCamHPa+PIKChYfPRUn6tnLqd5E TQx09YKYjv4c2cJPdHjBUphdUjtlvRClozhQvC9C5jzqIl1WBALK9wqsoHwDtr5iLuDb OsKrqXM4qd2/K/qqqiLSS5yqHx3CZd0wpEu6dL44Og1XdPLVAysVr05hFzhy/gh2YOlW RuH32DFydXokMOhZiPaHE8FhC2l9TesQCV9hBD75pSKsQZHWD9skNI1mm7HqcO5W8M9f RG31xqAfhjZgJTmLgkhCO/j+BVJbETZahj1nT5tGGKV1n2IhIMFmKgAkgLG/qd3Nfi0i fQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 34t7vmwaxj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 16 Nov 2020 14:47:19 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0AGEiSkA029534; Mon, 16 Nov 2020 14:47:18 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 34ts5us1sv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 16 Nov 2020 14:47:18 +0000 Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0AGElHKS024371; Mon, 16 Nov 2020 14:47:17 GMT Received: from localhost.localdomain (/92.157.91.83) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 16 Nov 2020 06:47:16 -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 v2 16/21] x86/pti: Execute system vector handlers on the kernel stack Date: Mon, 16 Nov 2020 15:47:52 +0100 Message-Id: <20201116144757.1920077-17-alexandre.chartre@oracle.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20201116144757.1920077-1-alexandre.chartre@oracle.com> References: <20201116144757.1920077-1-alexandre.chartre@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9806 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 spamscore=0 phishscore=0 suspectscore=0 mlxscore=0 malwarescore=0 bulkscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011160090 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9806 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 suspectscore=0 malwarescore=0 bulkscore=0 impostorscore=0 lowpriorityscore=0 spamscore=0 adultscore=0 mlxscore=0 priorityscore=1501 phishscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011160090 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