From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752916AbcG2NsF (ORCPT ); Fri, 29 Jul 2016 09:48:05 -0400 Received: from foss.arm.com ([217.140.101.70]:53598 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752283AbcG2NsD (ORCPT ); Fri, 29 Jul 2016 09:48:03 -0400 Date: Fri, 29 Jul 2016 14:48:05 +0100 From: Will Deacon To: Jason Cooper Cc: william.c.roberts@intel.com, Yann Droneaud , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, linux@arm.linux.org.uk, akpm@linux-foundation.org, keescook@chromium.org, tytso@mit.edu, arnd@arndb.de, gregkh@linuxfoundation.org, catalin.marinas@arm.com, ralf@linux-mips.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk, nnk@google.com, jeffv@google.com, dcashman@android.com Subject: Re: [PATCH 4/7] arm64: Use simpler API for random address requests Message-ID: <20160729134804.GJ16593@arm.com> References: <20160728204730.27453-1-jason@lakedaemon.net> <20160728204730.27453-5-jason@lakedaemon.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160728204730.27453-5-jason@lakedaemon.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 28, 2016 at 08:47:27PM +0000, Jason Cooper wrote: > Currently, all callers to randomize_range() set the length to 0 and > calculate end by adding a constant to the start address. We can > simplify the API to remove a bunch of needless checks and variables. > > Use the new randomize_addr(start, range) call to set the requested > address. > > Signed-off-by: Jason Cooper > --- > arch/arm64/kernel/process.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 6cd2612236dc..11bf454baf86 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -374,12 +374,8 @@ unsigned long arch_align_stack(unsigned long sp) > > unsigned long arch_randomize_brk(struct mm_struct *mm) > { > - unsigned long range_end = mm->brk; > - > if (is_compat_task()) > - range_end += 0x02000000; > + return randomize_addr(mm->brk, 0x02000000); > else > - range_end += 0x40000000; > - > - return randomize_range(mm->brk, range_end, 0) ? : mm->brk; > + return randomize_addr(mm->brk, 0x40000000); Looks fine to me, once the core code has settled down: Acked-by: Will Deacon Will