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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A814FC433E1 for ; Tue, 19 May 2020 20:00:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93DC32065F for ; Tue, 19 May 2020 20:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728628AbgESUAT (ORCPT ); Tue, 19 May 2020 16:00:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728390AbgEST7L (ORCPT ); Tue, 19 May 2020 15:59:11 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8356DC08C5C0; Tue, 19 May 2020 12:59:11 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jb8O2-00006H-DD; Tue, 19 May 2020 21:58:50 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 885E91C0845; Tue, 19 May 2020 21:58:40 +0200 (CEST) Date: Tue, 19 May 2020 19:58:40 -0000 From: "tip-bot2 for Thomas Gleixner" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/entry] x86/traps: Mark fixup_bad_iret() noinstr Cc: Thomas Gleixner , Alexandre Chartre , Masami Hiramatsu , Peter Zijlstra , Andy Lutomirski , x86 , LKML In-Reply-To: <20200505134903.346741553@linutronix.de> References: <20200505134903.346741553@linutronix.de> MIME-Version: 1.0 Message-ID: <158991832045.17951.2009680848290295284.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit 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 The following commit has been merged into the x86/entry branch of tip: Commit-ID: 68a05c6247d2aa67f5ada1009ffd19758e5914ea Gitweb: https://git.kernel.org/tip/68a05c6247d2aa67f5ada1009ffd19758e5914ea Author: Thomas Gleixner AuthorDate: Wed, 25 Mar 2020 19:53:38 +01:00 Committer: Thomas Gleixner CommitterDate: Tue, 19 May 2020 16:03:52 +02:00 x86/traps: Mark fixup_bad_iret() noinstr This is called from deep entry ASM in a situation where instrumentation will cause more harm than providing useful information. Switch from memmove() to memcpy() because memmove() can't be called from noinstr code. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Reviewed-by: Masami Hiramatsu Acked-by: Peter Zijlstra Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505134903.346741553@linutronix.de --- arch/x86/kernel/traps.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 48468f6..b2b3656 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -578,7 +578,7 @@ struct bad_iret_stack { struct pt_regs regs; }; -asmlinkage __visible notrace +asmlinkage __visible noinstr struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) { /* @@ -589,19 +589,21 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) * just below the IRET frame) and we want to pretend that the * exception came from the IRET target. */ - struct bad_iret_stack *new_stack = - (struct bad_iret_stack *)this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1; + struct bad_iret_stack tmp, *new_stack = + (struct bad_iret_stack *)__this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1; - /* Copy the IRET target to the new stack. */ - memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8); + /* Copy the IRET target to the temporary storage. */ + memcpy(&tmp.regs.ip, (void *)s->regs.sp, 5*8); /* Copy the remainder of the stack from the current stack. */ - memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip)); + memcpy(&tmp, s, offsetof(struct bad_iret_stack, regs.ip)); + + /* Update the entry stack */ + memcpy(new_stack, &tmp, sizeof(tmp)); BUG_ON(!user_mode(&new_stack->regs)); return new_stack; } -NOKPROBE_SYMBOL(fixup_bad_iret); #endif static bool is_sysenter_singlestep(struct pt_regs *regs)