From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753340AbdBJUZU (ORCPT ); Fri, 10 Feb 2017 15:25:20 -0500 Received: from mx2.suse.de ([195.135.220.15]:55013 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751141AbdBJUZT (ORCPT ); Fri, 10 Feb 2017 15:25:19 -0500 Date: Fri, 10 Feb 2017 21:25:06 +0100 From: Borislav Petkov To: Thomas Gleixner Cc: Dmitry Safonov , linux-kernel@vger.kernel.org, 0x7f454c46@gmail.com, Ingo Molnar , "H. Peter Anvin" , Andy Lutomirski , x86@kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv4 1/5] x86/mm: split arch_mmap_rnd() on compat/native versions Message-ID: <20170210202506.wwiinpiyy3ui6e5y@pd.tnic> References: <20170130120432.6716-1-dsafonov@virtuozzo.com> <20170130120432.6716-2-dsafonov@virtuozzo.com> <20170209135525.qlwrmlo7njk3fsaq@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 10, 2017 at 09:10:30PM +0100, Thomas Gleixner wrote: > On Thu, 9 Feb 2017, Borislav Petkov wrote: > > I can't say that I'm thrilled about the ifdeffery this is adding. > > > > But I can't think of a cleaner approach at a quick glance, though - > > that's generic and arch-specific code intertwined muck. Sad face. > > It's trivial enough to do .... > > Thanks, > > tglx > > --- > arch/x86/mm/mmap.c | 22 ++++++++++------------ > 1 file changed, 10 insertions(+), 12 deletions(-) > > --- a/arch/x86/mm/mmap.c > +++ b/arch/x86/mm/mmap.c > @@ -55,6 +55,10 @@ static unsigned long stack_maxrandom_siz > #define MIN_GAP (128*1024*1024UL + stack_maxrandom_size()) > #define MAX_GAP (TASK_SIZE/6*5) > > +#ifndef CONFIG_COMPAT > +# define mmap_rnd_compat_bits mmap_rnd_bits > +#endif > + > static int mmap_is_legacy(void) > { > if (current->personality & ADDR_COMPAT_LAYOUT) > @@ -66,20 +70,14 @@ static int mmap_is_legacy(void) > return sysctl_legacy_va_layout; > } > > -unsigned long arch_mmap_rnd(void) > +static unsigned long arch_rnd(unsigned int rndbits) > { > - unsigned long rnd; > - > - if (mmap_is_ia32()) > -#ifdef CONFIG_COMPAT > - rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1); > -#else > - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); > -#endif > - else > - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); > + return (get_random_long() & ((1UL << rndbits) - 1)) << PAGE_SHIFT; > +} > > - return rnd << PAGE_SHIFT; > +unsigned long arch_mmap_rnd(void) > +{ > + return arch_rnd(mmap_is_ia32() ? mmap_rnd_compat_bits : mmap_rnd_bits); > } Ha! Nice. :-) -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) -- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f200.google.com (mail-wj0-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 057326B0389 for ; Fri, 10 Feb 2017 15:25:20 -0500 (EST) Received: by mail-wj0-f200.google.com with SMTP id h7so12640579wjy.6 for ; Fri, 10 Feb 2017 12:25:19 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 25si3493416wrt.162.2017.02.10.12.25.18 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 10 Feb 2017 12:25:18 -0800 (PST) Date: Fri, 10 Feb 2017 21:25:06 +0100 From: Borislav Petkov Subject: Re: [PATCHv4 1/5] x86/mm: split arch_mmap_rnd() on compat/native versions Message-ID: <20170210202506.wwiinpiyy3ui6e5y@pd.tnic> References: <20170130120432.6716-1-dsafonov@virtuozzo.com> <20170130120432.6716-2-dsafonov@virtuozzo.com> <20170209135525.qlwrmlo7njk3fsaq@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner Cc: Dmitry Safonov , linux-kernel@vger.kernel.org, 0x7f454c46@gmail.com, Ingo Molnar , "H. Peter Anvin" , Andy Lutomirski , x86@kernel.org, linux-mm@kvack.org On Fri, Feb 10, 2017 at 09:10:30PM +0100, Thomas Gleixner wrote: > On Thu, 9 Feb 2017, Borislav Petkov wrote: > > I can't say that I'm thrilled about the ifdeffery this is adding. > > > > But I can't think of a cleaner approach at a quick glance, though - > > that's generic and arch-specific code intertwined muck. Sad face. > > It's trivial enough to do .... > > Thanks, > > tglx > > --- > arch/x86/mm/mmap.c | 22 ++++++++++------------ > 1 file changed, 10 insertions(+), 12 deletions(-) > > --- a/arch/x86/mm/mmap.c > +++ b/arch/x86/mm/mmap.c > @@ -55,6 +55,10 @@ static unsigned long stack_maxrandom_siz > #define MIN_GAP (128*1024*1024UL + stack_maxrandom_size()) > #define MAX_GAP (TASK_SIZE/6*5) > > +#ifndef CONFIG_COMPAT > +# define mmap_rnd_compat_bits mmap_rnd_bits > +#endif > + > static int mmap_is_legacy(void) > { > if (current->personality & ADDR_COMPAT_LAYOUT) > @@ -66,20 +70,14 @@ static int mmap_is_legacy(void) > return sysctl_legacy_va_layout; > } > > -unsigned long arch_mmap_rnd(void) > +static unsigned long arch_rnd(unsigned int rndbits) > { > - unsigned long rnd; > - > - if (mmap_is_ia32()) > -#ifdef CONFIG_COMPAT > - rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1); > -#else > - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); > -#endif > - else > - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); > + return (get_random_long() & ((1UL << rndbits) - 1)) << PAGE_SHIFT; > +} > > - return rnd << PAGE_SHIFT; > +unsigned long arch_mmap_rnd(void) > +{ > + return arch_rnd(mmap_is_ia32() ? mmap_rnd_compat_bits : mmap_rnd_bits); > } Ha! Nice. :-) -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix ImendA?rffer, Jane Smithard, Graham Norton, HRB 21284 (AG NA 1/4 rnberg) -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org