From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-4056489-1516723262-2-11459107113858425268 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1516723260; b=gmCU+fQVSd1oklCGskKk2SQjbPpr4Uebz2zxEFbshwa7Bmb PJTaLJlkThvTaGsOEeWmwvHHDLs0IoCJ70pVWNzNtTOWXmaqA5OhzRgnihcEi/rj Dqg8g3Og6EJh2fuSd9dqlH0U4b6PqRIVjnzdr05yyY2vbR5FzCI/9yujhPvdg4aB NOegqFEUt0EobB8XM+qYVupVy75Txbww3Za6W/penvw/H6Q7n7yQr4v1giy6qdLV VJsBUtuLX66YPLQT+MoorfQEtt4WblJXtFXA8o2lDKf7h0cUnp8kz/ioSRyhyhJi Mah4e5hSwLxZZWKaoqLolsBSdZGI01sdrO5j6Yw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=arctest; t=1516723260; bh=GZLWL0t4KqKvEARrKOHHb5+8j8n/cHBmMkjDxpzU8lk=; b=Ivub/O9WDRNg otAujNNYjyozpfCBiYLq2pxGM2w+Df/OAFvL1Ux/oE4e8oD+fUAQkhsMUQ0eRETb BR/j2x89v3yrX82L5oo39z2CEwT/VJBy1f+Rv7xHzU0y7sbpwR5cCULsKIZ6qX3h 4xd9l0gmdU8b+eWmEbMx1BwLDcXzaFQlONygbqeb4W1/V8wVo06TPIql/2gNGOG6 U1nVOE7eMZD5CJ9gMaf/FU+sssft+wX0jf/LDRsewLkvHz3ZdZzrJupGcD1oRp8+ kwYW1BPT0vNB+AMjd8K/GUZ6YrkB5dj5tEcSskbgaFnWcLk+HGJTnHKRaW1Hm0No Q4v8o6sLQg== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=efficios.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=efficios.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=efficios.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=efficios.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751426AbeAWQAp (ORCPT ); Tue, 23 Jan 2018 11:00:45 -0500 Received: from mail.efficios.com ([167.114.142.141]:34799 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752332AbeAWP6L (ORCPT ); Tue, 23 Jan 2018 10:58:11 -0500 From: Mathieu Desnoyers To: Ingo Molnar , Peter Zijlstra , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Andy Lutomirski , "Paul E . McKenney" , Boqun Feng , Andrew Hunter , Maged Michael , Avi Kivity , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Dave Watson , "H . Peter Anvin" , Andrea Parri , Russell King , Greg Hackmann , Will Deacon , David Sehr , Linus Torvalds , x86@kernel.org, Mathieu Desnoyers , Arnd Bergmann , linux-arch@vger.kernel.org Subject: [PATCH 07/11] x86: Implement sync_core_before_usermode (v3) Date: Tue, 23 Jan 2018 10:57:29 -0500 Message-Id: <20180123155733.3404-8-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180123155733.3404-1-mathieu.desnoyers@efficios.com> References: <20180123155733.3404-1-mathieu.desnoyers@efficios.com> Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Ensure that a core serializing instruction is issued before returning to user-mode. x86 implements return to user-space through sysexit, sysrel, and sysretq, which are not core serializing. Signed-off-by: Mathieu Desnoyers CC: Thomas Gleixner CC: Peter Zijlstra CC: Andy Lutomirski CC: Paul E. McKenney CC: Boqun Feng CC: Andrew Hunter CC: Maged Michael CC: Avi Kivity CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Michael Ellerman CC: Dave Watson CC: Ingo Molnar CC: "H. Peter Anvin" CC: Andrea Parri CC: Russell King CC: Greg Hackmann CC: Will Deacon CC: David Sehr CC: Linus Torvalds CC: Arnd Bergmann CC: x86@kernel.org CC: linux-arch@vger.kernel.org --- Changes since v1: - Fix prototype of sync_core_before_usermode in generic code (missing return type). - Add linux/processor.h include to sched/core.c. - Add ARCH_HAS_SYNC_CORE_BEFORE_USERMODE to init/Kconfig. - Fix linux/processor.h ifdef to target CONFIG_ARCH_HAS_SYNC_CORE_BEFORE_USERMODE rather than ARCH_HAS_SYNC_CORE_BEFORE_USERMODE. - Move empty static inline in processor.h to generic patch. Changes since v2: - Introduce arch/x86/include/asm/sync_core.h - Don't sync_core when KPTI is enabled, and when invoked from irq and nmi context. - Note: v2 was reviewed by Thomas Gleixner, but changes were introduced since. --- arch/x86/Kconfig | 1 + arch/x86/include/asm/sync_core.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) create mode 100644 arch/x86/include/asm/sync_core.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 20da391b5f32..0b44c8dd0e95 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -61,6 +61,7 @@ config X86 select ARCH_HAS_SG_CHAIN select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_HAS_STRICT_MODULE_RWX + select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE select ARCH_HAS_UBSAN_SANITIZE_ALL select ARCH_HAS_ZONE_DEVICE if X86_64 select ARCH_HAVE_NMI_SAFE_CMPXCHG diff --git a/arch/x86/include/asm/sync_core.h b/arch/x86/include/asm/sync_core.h new file mode 100644 index 000000000000..c67caafd3381 --- /dev/null +++ b/arch/x86/include/asm/sync_core.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SYNC_CORE_H +#define _ASM_X86_SYNC_CORE_H + +#include +#include +#include + +/* + * Ensure that a core serializing instruction is issued before returning + * to user-mode. x86 implements return to user-space through sysexit, + * sysrel, and sysretq, which are not core serializing. + */ +static inline void sync_core_before_usermode(void) +{ + /* With PTI, we unconditionally serialize before running user code. */ + if (static_cpu_has(X86_FEATURE_PTI)) + return; + /* + * Return from interrupt and NMI is done through iret, which is core + * serializing. + */ + if (in_irq() || in_nmi()) + return; + sync_core(); +} + +#endif /* _ASM_X86_SYNC_CORE_H */ -- 2.11.0