From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751454AbdJEHtT (ORCPT ); Thu, 5 Oct 2017 03:49:19 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:11820 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751272AbdJEHtS (ORCPT ); Thu, 5 Oct 2017 03:49:18 -0400 Subject: Re: [PATCH] powerpc: Default to enabling STRICT_KERNEL_RWX To: Kees Cook , linux-kernel@vger.kernel.org Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org References: <20171005034505.GA32157@beast> From: Christophe LEROY Message-ID: <6e6bf9ba-d66c-0bcc-358e-fed97b2ca5cd@c-s.fr> Date: Thu, 5 Oct 2017 09:49:06 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20171005034505.GA32157@beast> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 05/10/2017 à 05:45, Kees Cook a écrit : > When available, CONFIG_KERNEL_RWX should be default-enabled. On PPC32, this option implies deactivating BATs and/or LTLB mapping of the linear kernel address space, hence a significant performance degradation. So at least on PPC32, it should remain unselected by default. Christophe > > Cc: Benjamin Herrenschmidt > Cc: Paul Mackerras > Cc: Michael Ellerman > Cc: linuxppc-dev@lists.ozlabs.org > Signed-off-by: Kees Cook > --- > arch/powerpc/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 809c468edab1..9a549bbfc278 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -178,6 +178,7 @@ config PPC > select HAVE_ARCH_TRACEHOOK > select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION) > select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX > + select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT > select HAVE_CBPF_JIT if !PPC64 > select HAVE_CONTEXT_TRACKING if PPC64 > select HAVE_DEBUG_KMEMLEAK >