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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 D88F6C4BA04 for ; Tue, 25 Feb 2020 23:30:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B4FAA24684 for ; Tue, 25 Feb 2020 23:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730194AbgBYXaj (ORCPT ); Tue, 25 Feb 2020 18:30:39 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:55524 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729489AbgBYXZu (ORCPT ); Tue, 25 Feb 2020 18:25:50 -0500 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1j6ja6-0004aP-Gp; Wed, 26 Feb 2020 00:25:38 +0100 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id 3C91D104097; Wed, 26 Feb 2020 00:25:33 +0100 (CET) Message-Id: <20200225221305.719921962@linutronix.de> User-Agent: quilt/0.65 Date: Tue, 25 Feb 2020 23:08:06 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Steven Rostedt , Brian Gerst , Juergen Gross , Paolo Bonzini , Arnd Bergmann Subject: [patch 5/8] x86/entry/common: Provide trace/kprobe safe exit to user space functions References: <20200225220801.571835584@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Split prepare_enter_to_user_mode() and mark it notrace/noprobe so the irq flags tracing on return can be put into it. Signed-off-by: Thomas Gleixner --- arch/x86/entry/common.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -196,7 +196,7 @@ static void exit_to_usermode_loop(struct } /* Called with IRQs disabled. */ -__visible inline void prepare_exit_to_usermode(struct pt_regs *regs) +static inline void __prepare_exit_to_usermode(struct pt_regs *regs) { struct thread_info *ti = current_thread_info(); u32 cached_flags; @@ -241,6 +241,12 @@ static void exit_to_usermode_loop(struct mds_user_clear_cpu_buffers(); } +__visible inline notrace void prepare_exit_to_usermode(struct pt_regs *regs) +{ + __prepare_exit_to_usermode(regs); +} +NOKPROBE_SYMBOL(prepare_exit_to_usermode); + #define SYSCALL_EXIT_WORK_FLAGS \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT) @@ -271,7 +277,7 @@ static void syscall_slow_exit_work(struc * Called with IRQs on and fully valid regs. Returns with IRQs off in a * state such that we can immediately switch to user mode. */ -__visible inline void syscall_return_slowpath(struct pt_regs *regs) +__visible inline notrace void syscall_return_slowpath(struct pt_regs *regs) { struct thread_info *ti = current_thread_info(); u32 cached_flags = READ_ONCE(ti->flags); @@ -292,8 +298,9 @@ static void syscall_slow_exit_work(struc syscall_slow_exit_work(regs, cached_flags); local_irq_disable(); - prepare_exit_to_usermode(regs); + __prepare_exit_to_usermode(regs); } +NOKPROBE_SYMBOL(syscall_return_slowpath); #ifdef CONFIG_X86_64 static __always_inline @@ -417,7 +424,7 @@ static __always_inline long do_fast_sysc /* User code screwed up. */ local_irq_disable(); regs->ax = -EFAULT; - prepare_exit_to_usermode(regs); + __prepare_exit_to_usermode(regs); return 0; /* Keep it simple: use IRET. */ }