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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 D6BDEC433DB for ; Fri, 5 Feb 2021 13:59:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F2D5E64FC4 for ; Fri, 5 Feb 2021 13:59:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2D5E64FC4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 388746B0005; Fri, 5 Feb 2021 08:59:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 338006B006C; Fri, 5 Feb 2021 08:59:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 227236B006E; Fri, 5 Feb 2021 08:59:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0083.hostedemail.com [216.40.44.83]) by kanga.kvack.org (Postfix) with ESMTP id 0D81F6B0005 for ; Fri, 5 Feb 2021 08:59:35 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id CCA17181AEF15 for ; Fri, 5 Feb 2021 13:59:34 +0000 (UTC) X-FDA: 77784371868.07.ship65_2c0ecaf275e5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id B14231803F9A2 for ; Fri, 5 Feb 2021 13:59:34 +0000 (UTC) X-HE-Tag: ship65_2c0ecaf275e5 X-Filterd-Recvd-Size: 3746 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 5 Feb 2021 13:59:34 +0000 (UTC) Received: from zn.tnic (p200300ec2f0bad00265302c9d3d9d03f.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:ad00:2653:2c9:d3d9:d03f]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 8E2061EC046E; Fri, 5 Feb 2021 14:59:32 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1612533572; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=fejHEgISzAriaXk58/yJbjLx87IH2APQ6UHwJdugJkM=; b=MBU/kzais+IBkRkPz4TnWRG+A8fD6KoCqQ6ftWcnyATMdURu4VClIpP1aTBHJT2ew63u9h qrHbFq4H3uWvu++s5O3o23kF4tHNf7UN9W2qMtI0Z+ErEh7EMxLUZ9qSQ5pCStCG03ZpIi fe0oEtaQDEIUKaLlv6mshLw/6lwGVek= Date: Fri, 5 Feb 2021 14:59:27 +0100 From: Borislav Petkov To: Yu-cheng Yu Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Michael Kerrisk Subject: Re: [PATCH v19 06/25] x86/cet: Add control-protection fault handler Message-ID: <20210205135927.GH17488@zn.tnic> References: <20210203225547.32221-1-yu-cheng.yu@intel.com> <20210203225547.32221-7-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210203225547.32221-7-yu-cheng.yu@intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Feb 03, 2021 at 02:55:28PM -0800, Yu-cheng Yu wrote: > +DEFINE_IDTENTRY_ERRORCODE(exc_control_protection) > +{ > + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, > + DEFAULT_RATELIMIT_BURST); > + struct task_struct *tsk; > + > + if (!user_mode(regs)) { > + pr_emerg("PANIC: unexpected kernel control protection fault\n"); > + die("kernel control protection fault", regs, error_code); > + panic("Machine halted."); > + } > + > + cond_local_irq_enable(regs); > + > + if (!boot_cpu_has(X86_FEATURE_CET)) > + WARN_ONCE(1, "Control protection fault with CET support disabled\n"); > + > + tsk = current; > + tsk->thread.error_code = error_code; > + tsk->thread.trap_nr = X86_TRAP_CP; > + > + if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && > + __ratelimit(&rs)) { I can't find it written down anywhere why the ratelimiting is needed at all? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette