From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932894AbdDGJhm (ORCPT ); Fri, 7 Apr 2017 05:37:42 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:57648 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932828AbdDGJhd (ORCPT ); Fri, 7 Apr 2017 05:37:33 -0400 Date: Fri, 7 Apr 2017 11:37:08 +0200 From: Peter Zijlstra To: Kees Cook Cc: kernel-hardening@lists.openwall.com, Mark Rutland , Andy Lutomirski , Hoeun Ryu , PaX Team , Emese Revfy , Russell King , x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() Message-ID: <20170407093708.4ozbt3azbhqur4d4@hirez.programming.kicks-ass.net> References: <1490811363-93944-1-git-send-email-keescook@chromium.org> <1490811363-93944-5-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490811363-93944-5-git-send-email-keescook@chromium.org> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 29, 2017 at 11:15:56AM -0700, Kees Cook wrote: > +static __always_inline unsigned long __arch_rare_write_end(void) > +{ > + unsigned long cr0; > + > + barrier(); > + cr0 = read_cr0() ^ X86_CR0_WP; > + BUG_ON(!(cr0 & X86_CR0_WP)); > + write_cr0(cr0); > + barrier(); > + preempt_enable_no_resched(); NAK > + return cr0 ^ X86_CR0_WP; > +} From mboxrd@z Thu Jan 1 00:00:00 1970 From: peterz@infradead.org (Peter Zijlstra) Date: Fri, 7 Apr 2017 11:37:08 +0200 Subject: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() In-Reply-To: <1490811363-93944-5-git-send-email-keescook@chromium.org> References: <1490811363-93944-1-git-send-email-keescook@chromium.org> <1490811363-93944-5-git-send-email-keescook@chromium.org> Message-ID: <20170407093708.4ozbt3azbhqur4d4@hirez.programming.kicks-ass.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Mar 29, 2017 at 11:15:56AM -0700, Kees Cook wrote: > +static __always_inline unsigned long __arch_rare_write_end(void) > +{ > + unsigned long cr0; > + > + barrier(); > + cr0 = read_cr0() ^ X86_CR0_WP; > + BUG_ON(!(cr0 & X86_CR0_WP)); > + write_cr0(cr0); > + barrier(); > + preempt_enable_no_resched(); NAK > + return cr0 ^ X86_CR0_WP; > +} From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 7 Apr 2017 11:37:08 +0200 From: Peter Zijlstra Message-ID: <20170407093708.4ozbt3azbhqur4d4@hirez.programming.kicks-ass.net> References: <1490811363-93944-1-git-send-email-keescook@chromium.org> <1490811363-93944-5-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490811363-93944-5-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] Re: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() To: Kees Cook Cc: kernel-hardening@lists.openwall.com, Mark Rutland , Andy Lutomirski , Hoeun Ryu , PaX Team , Emese Revfy , Russell King , x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-ID: On Wed, Mar 29, 2017 at 11:15:56AM -0700, Kees Cook wrote: > +static __always_inline unsigned long __arch_rare_write_end(void) > +{ > + unsigned long cr0; > + > + barrier(); > + cr0 = read_cr0() ^ X86_CR0_WP; > + BUG_ON(!(cr0 & X86_CR0_WP)); > + write_cr0(cr0); > + barrier(); > + preempt_enable_no_resched(); NAK > + return cr0 ^ X86_CR0_WP; > +}