From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot1-f72.google.com (mail-ot1-f72.google.com [209.85.210.72]) by kanga.kvack.org (Postfix) with ESMTP id EFA4B6B79CA for ; Thu, 6 Dec 2018 06:51:38 -0500 (EST) Received: by mail-ot1-f72.google.com with SMTP id s12so52427otc.12 for ; Thu, 06 Dec 2018 03:51:38 -0800 (PST) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id a9si50097otc.300.2018.12.06.03.51.37 for ; Thu, 06 Dec 2018 03:51:38 -0800 (PST) Date: Thu, 6 Dec 2018 11:51:33 +0000 From: Catalin Marinas Subject: Re: [PATCH V4 6/6] arm64: mm: Allow forcing all userspace addresses to 52-bit Message-ID: <20181206115132.GD54495@arrakis.emea.arm.com> References: <20181205164145.24568-1-steve.capper@arm.com> <20181205164145.24568-7-steve.capper@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181205164145.24568-7-steve.capper@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Steve Capper Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, will.deacon@arm.com, jcm@redhat.com, ard.biesheuvel@linaro.org On Wed, Dec 05, 2018 at 04:41:45PM +0000, Steve Capper wrote: > On arm64 52-bit VAs are provided to userspace when a hint is supplied to > mmap. This helps maintain compatibility with software that expects at > most 48-bit VAs to be returned. > > In order to help identify software that has 48-bit VA assumptions, this > patch allows one to compile a kernel where 52-bit VAs are returned by > default on HW that supports it. > > This feature is intended to be for development systems only. > > Signed-off-by: Steve Capper Acked-by: Catalin Marinas