From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:49422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729791AbgKIQYa (ORCPT ); Mon, 9 Nov 2020 11:24:30 -0500 From: Mike Rapoport Subject: [PATCH v6 0/4] arch, mm: improve robustness of direct map manipulation Date: Mon, 9 Nov 2020 18:24:11 +0200 Message-Id: <20201109162415.13764-1-rppt@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-ID: To: Andrew Morton Cc: Albert Ou , Andy Lutomirski , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Christian Borntraeger , Christoph Lameter , "David S. Miller" , Dave Hansen , David Hildenbrand , David Rientjes , "Edgecombe, Rick P" , "H. Peter Anvin" , Heiko Carstens , Ingo Molnar , Joonsoo Kim , "Kirill A . Shutemov" , "Kirill A. Shutemov" , Len Brown , Michael Ellerman , Mike Rapoport , Mike Rapoport , Palmer Dabbelt , Paul Mackerras , Paul Walmsley , Pavel Machek , Pekka Enberg , Peter Zijlstra , "Rafael J. Wysocki" , Thomas Gleixner , Vasily Gorbik , Vlastimil Babka , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, x86@kernel.org From: Mike Rapoport Hi, During recent discussion about KVM protected memory, David raised a concern about usage of __kernel_map_pages() outside of DEBUG_PAGEALLOC scope [1]. Indeed, for architectures that define CONFIG_ARCH_HAS_SET_DIRECT_MAP it is possible that __kernel_map_pages() would fail, but since this function is void, the failure will go unnoticed. Moreover, there's lack of consistency of __kernel_map_pages() semantics across architectures as some guard this function with #ifdef DEBUG_PAGEALLOC, some refuse to update the direct map if page allocation debugging is disabled at run time and some allow modifying the direct map regardless of DEBUG_PAGEALLOC settings. This set straightens this out by restoring dependency of __kernel_map_pages() on DEBUG_PAGEALLOC and updating the call sites accordingly. Since currently the only user of __kernel_map_pages() outside DEBUG_PAGEALLOC is hibernation, it is updated to make direct map accesses there more explicit. [1] https://lore.kernel.org/lkml/2759b4bf-e1e3-d006-7d86-78a40348269d@redhat.com v6 changes: * revert slab changes to avoid redundant check of static key v5 changes: * use pairs of _map()/_unmap() functions instead of _map(..., int enable) as Vlastimil suggested https://lore.kernel.org/lkml/20201108065758.1815-1-rppt@kernel.org v4 changes: * s/WARN_ON/pr_warn_once/ per David and Kirill * rebase on v5.10-rc2 * add Acked/Reviewed tags https://lore.kernel.org/lkml/20201103162057.22916-1-rppt@kernel.org v3 changes: * update arm64 changes to avoid regression, per Rick's comments * fix bisectability https://lore.kernel.org/lkml/20201101170815.9795-1-rppt@kernel.org v2 changes: * Rephrase patch 2 changelog to better describe the change intentions and implications * Move removal of kernel_map_pages() from patch 1 to patch 2, per David https://lore.kernel.org/lkml/20201029161902.19272-1-rppt@kernel.org v1: https://lore.kernel.org/lkml/20201025101555.3057-1-rppt@kernel.org Mike Rapoport (4): mm: introduce debug_pagealloc_{map,unmap}_pages() helpers PM: hibernate: make direct map manipulations more explicit arch, mm: restore dependency of __kernel_map_pages() on DEBUG_PAGEALLOC arch, mm: make kernel_page_present() always available arch/Kconfig | 3 +++ arch/arm64/Kconfig | 4 +-- arch/arm64/include/asm/cacheflush.h | 1 + arch/arm64/mm/pageattr.c | 6 +++-- arch/powerpc/Kconfig | 5 +--- arch/riscv/Kconfig | 4 +-- arch/riscv/include/asm/pgtable.h | 2 -- arch/riscv/include/asm/set_memory.h | 1 + arch/riscv/mm/pageattr.c | 31 ++++++++++++++++++++++ arch/s390/Kconfig | 4 +-- arch/sparc/Kconfig | 4 +-- arch/x86/Kconfig | 4 +-- arch/x86/include/asm/set_memory.h | 1 + arch/x86/mm/pat/set_memory.c | 4 +-- include/linux/mm.h | 40 ++++++++++++++--------------- include/linux/set_memory.h | 5 ++++ kernel/power/snapshot.c | 38 +++++++++++++++++++++++++-- mm/memory_hotplug.c | 3 +-- mm/page_alloc.c | 6 ++--- 19 files changed, 113 insertions(+), 53 deletions(-) -- 2.28.0