From patchwork Fri May 8 14:40:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joerg Roedel X-Patchwork-Id: 194211 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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 6E505C38A2A for ; Fri, 8 May 2020 14:40:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B5FF2496A for ; Fri, 8 May 2020 14:40:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728085AbgEHOkw (ORCPT ); Fri, 8 May 2020 10:40:52 -0400 Received: from 8bytes.org ([81.169.241.247]:41590 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727828AbgEHOkw (ORCPT ); Fri, 8 May 2020 10:40:52 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 404DF423; Fri, 8 May 2020 16:40:50 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Cc: hpa@zytor.com, Dave Hansen , Andy Lutomirski , Peter Zijlstra , rjw@rjwysocki.net, Arnd Bergmann , Andrew Morton , Steven Rostedt , Vlastimil Babka , Michal Hocko , Joerg Roedel , joro@8bytes.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 0/7] mm: Get rid of vmalloc_sync_(un)mappings() Date: Fri, 8 May 2020 16:40:36 +0200 Message-Id: <20200508144043.13893-1-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi, after the recent issue with vmalloc and tracing code[1] on x86 and a long history of previous issues related to the vmalloc_sync_mappings() interface, I thought the time has come to remove it. Please see [2], [3], and [4] for some other issues in the past. The patches are based on v5.7-rc4 and add tracking of page-table directory changes to the vmalloc and ioremap code. Depending on which page-table levels changes have been made, a new per-arch function is called: arch_sync_kernel_mappings(). On x86-64 with 4-level paging, this function will not be called more than 64 times in a systems runtime (because vmalloc-space takes 64 PGD entries which are only populated, but never cleared). As a side effect this also allows to get rid of vmalloc faults on x86, making it safe to touch vmalloc'ed memory in the page-fault handler. Note that this potentially includes per-cpu memory. The code is tested on x86-64, x86-32 with and without PAE. It also fixes the issue described in [1]. Additionally this code has been compile-tested on almost all architectures supported by Linux. I couldn't find working compilers for hexagon and unicore32, so these are not tested. Please review. Regards, Joerg [1] https://lore.kernel.org/lkml/20200430141120.GA8135@suse.de/ [2] https://lore.kernel.org/lkml/20191009124418.8286-1-joro@8bytes.org/ [3] https://lore.kernel.org/lkml/20190719184652.11391-1-joro@8bytes.org/ [4] https://lore.kernel.org/lkml/20191126111119.GA110513@gmail.com/ Joerg Roedel (7): mm: Add functions to track page directory modifications mm/vmalloc: Track which page-table levels were modified mm/ioremap: Track which page-table levels were modified x86/mm/64: Implement arch_sync_kernel_mappings() x86/mm/32: Implement arch_sync_kernel_mappings() mm: Remove vmalloc_sync_(un)mappings() x86/mm: Remove vmalloc faulting arch/x86/include/asm/pgtable-2level_types.h | 2 + arch/x86/include/asm/pgtable-3level_types.h | 2 + arch/x86/include/asm/pgtable_64_types.h | 2 + arch/x86/include/asm/switch_to.h | 23 --- arch/x86/kernel/setup_percpu.c | 6 +- arch/x86/mm/fault.c | 176 +------------------- arch/x86/mm/init_64.c | 5 + arch/x86/mm/pti.c | 8 +- drivers/acpi/apei/ghes.c | 6 - include/asm-generic/5level-fixup.h | 5 +- include/asm-generic/pgtable.h | 23 +++ include/linux/mm.h | 46 +++++ include/linux/vmalloc.h | 13 +- kernel/notifier.c | 1 - lib/ioremap.c | 46 +++-- mm/nommu.c | 12 -- mm/vmalloc.c | 109 +++++++----- 17 files changed, 199 insertions(+), 286 deletions(-)