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=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 E4206C433E4 for ; Fri, 17 Jul 2020 09:17:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF7682070E for ; Fri, 17 Jul 2020 09:17:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="1GK9EL0M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725932AbgGQJRb (ORCPT ); Fri, 17 Jul 2020 05:17:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbgGQJRb (ORCPT ); Fri, 17 Jul 2020 05:17:31 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F9DCC061755; Fri, 17 Jul 2020 02:17:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=pcQ0H1o6p26C2vKLZMF/SJZnMQU+q3kwcSeFrBwvG4U=; b=1GK9EL0Mygx6wkzcHli7MajxZJ 9bdhJlSKGlg4PMmK23HdyR74DFHwv0hwspiU36sq/NpoEbxvPgpHX+8UyWNxtplg/0VsSXxHCiPB3 vFRbTtyHpuDavKAh5w7zgL1ghadeqPivAdZCXA0naaJhiCuhyiecFBb+pzLL7zWi9zOvxepXMvaQN ntvXivnC5cIE5QyoWA0OpNwPZQrVkbCA07py36E1hxi0uGtUkzP/EmssVu2Q7jz/ZEso4gZGV7W+F m5QxMYoo9/iJWWSIgBtc57v9llapUacsJoD8uETqbubjS8m9fifXpugMechsC7FZGC8PNVM2D9NmB Pjg04+Jw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jwMUc-0002bP-4T; Fri, 17 Jul 2020 09:17:22 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 163AB3003D8; Fri, 17 Jul 2020 11:17:19 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0035129CF6F50; Fri, 17 Jul 2020 11:17:18 +0200 (CEST) Date: Fri, 17 Jul 2020 11:17:18 +0200 From: Peter Zijlstra To: ira.weiny@intel.com Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , x86@kernel.org, Dave Hansen , Dan Williams , Vishal Verma , Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH RFC V2 12/17] memremap: Add zone device access protection Message-ID: <20200717091718.GA10769@hirez.programming.kicks-ass.net> References: <20200717072056.73134-1-ira.weiny@intel.com> <20200717072056.73134-13-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200717072056.73134-13-ira.weiny@intel.com> Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Fri, Jul 17, 2020 at 12:20:51AM -0700, ira.weiny@intel.com wrote: > +void dev_access_disable(void) > +{ > + unsigned long flags; > + > + if (!static_branch_unlikely(&dev_protection_static_key)) > + return; > + > + local_irq_save(flags); > + current->dev_page_access_ref--; > + if (current->dev_page_access_ref == 0) if (!--current->dev_page_access_ref) > + pks_update_protection(dev_page_pkey, PKEY_DISABLE_ACCESS); > + local_irq_restore(flags); > +} > +EXPORT_SYMBOL_GPL(dev_access_disable); > + > +void dev_access_enable(void) > +{ > + unsigned long flags; > + > + if (!static_branch_unlikely(&dev_protection_static_key)) > + return; > + > + local_irq_save(flags); > + /* 0 clears the PKEY_DISABLE_ACCESS bit, allowing access */ > + if (current->dev_page_access_ref == 0) > + pks_update_protection(dev_page_pkey, 0); > + current->dev_page_access_ref++; if (!current->dev_page_access_ref++) > + local_irq_restore(flags); > +} > +EXPORT_SYMBOL_GPL(dev_access_enable); Also, you probably want something like: static __always_inline devm_access_disable(void) { if (static_branch_unlikely(&dev_protection_static_key)) __devm_access_disable(); } static __always_inline devm_access_enable(void) { if (static_branch_unlikely(&dev_protection_static_key)) __devm_access_enable(); }