From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751964AbcFKKbY (ORCPT ); Sat, 11 Jun 2016 06:31:24 -0400 Received: from terminus.zytor.com ([198.137.202.10]:48618 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751115AbcFKKbW (ORCPT ); Sat, 11 Jun 2016 06:31:22 -0400 Date: Sat, 11 Jun 2016 02:34:10 -0700 From: tip-bot for Andy Lutomirski Message-ID: Cc: xen-devel@lists.xen.org, bp@alien8.de, boris.ostrovsky@oracle.com, keescook@chromium.org, luto@kernel.org, mingo@kernel.org, david.vrabel@citrix.com, hpa@zytor.com, torvalds@linux-foundation.org, luto@amacapital.net, tglx@linutronix.de, peterz@infradead.org, linux-kernel@vger.kernel.org, brgerst@gmail.com, konrad.wilk@oracle.com, jbeulich@suse.com, andrew.cooper3@citrix.com, dvrabel@cantab.net, dvlasenk@redhat.com Reply-To: hpa@zytor.com, david.vrabel@citrix.com, xen-devel@lists.xen.org, bp@alien8.de, boris.ostrovsky@oracle.com, mingo@kernel.org, luto@kernel.org, keescook@chromium.org, dvrabel@cantab.net, dvlasenk@redhat.com, linux-kernel@vger.kernel.org, jbeulich@suse.com, konrad.wilk@oracle.com, brgerst@gmail.com, andrew.cooper3@citrix.com, torvalds@linux-foundation.org, luto@amacapital.net, tglx@linutronix.de, peterz@infradead.org In-Reply-To: <0706f1a2538e481194514197298cca6b5e3f2638.1464129798.git.luto@kernel.org> References: <0706f1a2538e481194514197298cca6b5e3f2638.1464129798.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/xen: Simplify set_aliased_prot() Git-Commit-ID: 99158f10e91768d34c5004c40c42f802b719bcae X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 99158f10e91768d34c5004c40c42f802b719bcae Gitweb: http://git.kernel.org/tip/99158f10e91768d34c5004c40c42f802b719bcae Author: Andy Lutomirski AuthorDate: Tue, 24 May 2016 15:48:38 -0700 Committer: Ingo Molnar CommitDate: Sat, 11 Jun 2016 11:28:11 +0200 x86/xen: Simplify set_aliased_prot() A year ago, via the following commit: aa1acff356bb ("x86/xen: Probe target addresses in set_aliased_prot() before the hypercall") I added an explicit probe to work around a hypercall issue. The code can be simplified by using probe_kernel_read(). No change in functionality. Signed-off-by: Andy Lutomirski Reviewed-by: Andrew Cooper Acked-by: David Vrabel Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: David Vrabel Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jan Beulich Cc: Kees Cook Cc: Konrad Rzeszutek Wilk Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: xen-devel Link: http://lkml.kernel.org/r/0706f1a2538e481194514197298cca6b5e3f2638.1464129798.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/xen/enlighten.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 760789a..0f87db2 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -521,9 +521,7 @@ static void set_aliased_prot(void *v, pgprot_t prot) preempt_disable(); - pagefault_disable(); /* Avoid warnings due to being atomic. */ - __get_user(dummy, (unsigned char __user __force *)v); - pagefault_enable(); + probe_kernel_read(&dummy, v, 1); if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) BUG();