From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2B04C433E0 for ; Thu, 18 Jun 2020 05:37:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84A3E20897 for ; Thu, 18 Jun 2020 05:37:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727022AbgFRFhS (ORCPT ); Thu, 18 Jun 2020 01:37:18 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:11153 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725912AbgFRFhS (ORCPT ); Thu, 18 Jun 2020 01:37:18 -0400 X-Originating-IP: 90.112.45.105 Received: from [192.168.1.14] (lfbn-gre-1-325-105.w90-112.abo.wanadoo.fr [90.112.45.105]) (Authenticated sender: alex@ghiti.fr) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id F4009240002; Thu, 18 Jun 2020 05:37:14 +0000 (UTC) Subject: Re: [PATCH v2 0/8] Introduce sv48 support To: Paul Walmsley , Palmer Dabbelt , Zong Li , Anup Patel , Christoph Hellwig , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org References: <20200603081104.14004-1-alex@ghiti.fr> From: Alex Ghiti Message-ID: <0fbb7c9b-d221-5bf8-ddc0-3938066a09d0@ghiti.fr> Date: Thu, 18 Jun 2020 01:37:14 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200603081104.14004-1-alex@ghiti.fr> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Content-Language: fr Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Palmer, Le 6/3/20 à 4:10 AM, Alexandre Ghiti a écrit : > This patchset implements sv48 support at runtime. The kernel will try to > boot with 4-level page table and will fallback to 3-level if the HW does not > support it. > > The biggest advantage is that we only have one kernel for 64bit, which > is way easier to maintain. > > Folding the 4th level into a 3-level page table has almost no cost at > runtime. But as mentioned Palmer, the relocatable code generated is less > performant. > > At the moment, there is no way to build a 3-level page table non-relocatable > 64bit kernel. We agreed that distributions will use this runtime configuration > anyway, but Palmer proposed to introduce a new Kconfig, which I will do later > as sv48 support was asked for 5.8. > > Finally, the user can now ask for sv39 explicitly by using the device-tree > which will reduce memory footprint and reduce the number of memory accesses > in case of TLB miss. > > Changes in v2: > * Move variable declarations to pgtable.h in patch 5/7 as suggested by Anup > * Restore mmu-type properties in patch 6 as suggested by Anup > * Fix unused variable in patch 5 that was used in patch 6 > * Fix SPARSEMEM build (patch 2 was modified so I dropped the Reviewed-by) > * Applied various Reviewed-by > > Alexandre Ghiti (8): > riscv: Get rid of compile time logic with MAX_EARLY_MAPPING_SIZE > riscv: Allow to dynamically define VA_BITS > riscv: Simplify MAXPHYSMEM config > riscv: Prepare ptdump for vm layout dynamic addresses > riscv: Implement sv48 support > riscv: Allow user to downgrade to sv39 when hw supports sv48 > riscv: Use pgtable_l4_enabled to output mmu type in cpuinfo > riscv: Explicit comment about user virtual address space size > > arch/riscv/Kconfig | 34 ++--- > arch/riscv/include/asm/csr.h | 3 +- > arch/riscv/include/asm/fixmap.h | 1 + > arch/riscv/include/asm/page.h | 15 +++ > arch/riscv/include/asm/pgalloc.h | 36 ++++++ > arch/riscv/include/asm/pgtable-64.h | 97 +++++++++++++- > arch/riscv/include/asm/pgtable.h | 31 ++++- > arch/riscv/include/asm/sparsemem.h | 6 +- > arch/riscv/kernel/cpu.c | 23 ++-- > arch/riscv/kernel/head.S | 3 +- > arch/riscv/mm/context.c | 2 +- > arch/riscv/mm/init.c | 194 ++++++++++++++++++++++++---- > arch/riscv/mm/ptdump.c | 49 +++++-- > 13 files changed, 412 insertions(+), 82 deletions(-) > Do you any remark regarding this patchset and the others ? Thanks, Alex