From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752551AbeBEVkm (ORCPT ); Mon, 5 Feb 2018 16:40:42 -0500 Received: from terminus.zytor.com ([65.50.211.136]:45547 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752489AbeBEVk3 (ORCPT ); Mon, 5 Feb 2018 16:40:29 -0500 Date: Mon, 5 Feb 2018 13:28:41 -0800 From: tip-bot for Mathieu Desnoyers Message-ID: Cc: paulmck@linux.vnet.ibm.com, hpa@zytor.com, tglx@linutronix.de, linux@armlinux.org.uk, paulus@samba.org, parri.andrea@gmail.com, torvalds@linux-foundation.org, peterz@infradead.org, linux-kernel@vger.kernel.org, sehr@google.com, ahh@google.com, luto@kernel.org, avi@scylladb.com, mathieu.desnoyers@efficios.com, mingo@kernel.org, mpe@ellerman.id.au, will.deacon@arm.com, davejwatson@fb.com, benh@kernel.crashing.org, arnd@arndb.de, ghackmann@google.com, maged.michael@gmail.com, boqun.feng@gmail.com Reply-To: hpa@zytor.com, paulmck@linux.vnet.ibm.com, tglx@linutronix.de, sehr@google.com, linux-kernel@vger.kernel.org, peterz@infradead.org, torvalds@linux-foundation.org, parri.andrea@gmail.com, paulus@samba.org, linux@armlinux.org.uk, ahh@google.com, avi@scylladb.com, luto@kernel.org, mathieu.desnoyers@efficios.com, arnd@arndb.de, benh@kernel.crashing.org, will.deacon@arm.com, davejwatson@fb.com, mpe@ellerman.id.au, mingo@kernel.org, boqun.feng@gmail.com, maged.michael@gmail.com, ghackmann@google.com In-Reply-To: <20180129202020.8515-8-mathieu.desnoyers@efficios.com> References: <20180129202020.8515-8-mathieu.desnoyers@efficios.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] lockin/x86: Implement sync_core_before_usermode() Git-Commit-ID: ac1ab12a3e6e878274e7107c8c6f326694a1c1f3 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: ac1ab12a3e6e878274e7107c8c6f326694a1c1f3 Gitweb: https://git.kernel.org/tip/ac1ab12a3e6e878274e7107c8c6f326694a1c1f3 Author: Mathieu Desnoyers AuthorDate: Mon, 29 Jan 2018 15:20:16 -0500 Committer: Ingo Molnar CommitDate: Mon, 5 Feb 2018 21:34:57 +0100 lockin/x86: Implement sync_core_before_usermode() 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 Acked-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: Andrea Parri Cc: Andrew Hunter Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Avi Kivity Cc: Benjamin Herrenschmidt Cc: Boqun Feng Cc: Dave Watson Cc: David Sehr Cc: Greg Hackmann Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Maged Michael Cc: Michael Ellerman Cc: Paul E. McKenney Cc: Paul Mackerras Cc: Russell King Cc: Will Deacon Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/20180129202020.8515-8-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 1 + arch/x86/include/asm/sync_core.h | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 423e4b6..31030ad 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 0000000..c67caaf --- /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 */