arch, mm: improve robustness of direct map manipulation
| From: | Mike Rapoport <rppt-AT-kernel.org> | |
| To: | Andrew Morton <akpm-AT-linux-foundation.org> | |
| Subject: | [PATCH v5 0/5] arch, mm: improve robustness of direct map manipulation | |
| Date: | Sun, 08 Nov 2020 08:57:53 +0200 | |
| Message-ID: | <20201108065758.1815-1-rppt@kernel.org> | |
| Cc: | Albert Ou <aou-AT-eecs.berkeley.edu>, Andy Lutomirski <luto-AT-kernel.org>, Benjamin Herrenschmidt <benh-AT-kernel.crashing.org>, Borislav Petkov <bp-AT-alien8.de>, Catalin Marinas <catalin.marinas-AT-arm.com>, Christian Borntraeger <borntraeger-AT-de.ibm.com>, Christoph Lameter <cl-AT-linux.com>, "David S. Miller" <davem-AT-davemloft.net>, Dave Hansen <dave.hansen-AT-linux.intel.com>, David Hildenbrand <david-AT-redhat.com>, David Rientjes <rientjes-AT-google.com>, "Edgecombe, Rick P" <rick.p.edgecombe-AT-intel.com>, "H. Peter Anvin" <hpa-AT-zytor.com>, Heiko Carstens <hca-AT-linux.ibm.com>, Ingo Molnar <mingo-AT-redhat.com>, Joonsoo Kim <iamjoonsoo.kim-AT-lge.com>, "Kirill A . Shutemov" <kirill.shutemov-AT-linux.intel.com>, "Kirill A. Shutemov" <kirill-AT-shutemov.name>, Len Brown <len.brown-AT-intel.com>, Michael Ellerman <mpe-AT-ellerman.id.au>, Mike Rapoport <rppt-AT-kernel.org>, Mike Rapoport <rppt-AT-linux.ibm.com>, Palmer Dabbelt <palmer-AT-dabbelt.com>, Paul Mackerras <paulus-AT-samba.org>, Paul Walmsley <paul.walmsley-AT-sifive.com>, Pavel Machek <pavel-AT-ucw.cz>, Pekka Enberg <penberg-AT-kernel.org>, Peter Zijlstra <peterz-AT-infradead.org>, "Rafael J. Wysocki" <rjw-AT-rjwysocki.net>, Thomas Gleixner <tglx-AT-linutronix.de>, Vasily Gorbik <gor-AT-linux.ibm.com>, Vlastimil Babka <vbabka-AT-suse.cz>, Will Deacon <will-AT-kernel.org>, linux-arm-kernel-AT-lists.infradead.org, linux-kernel-AT-vger.kernel.org, linux-mm-AT-kvack.org, linux-pm-AT-vger.kernel.org, linux-riscv-AT-lists.infradead.org, linux-s390-AT-vger.kernel.org, linuxppc-dev-AT-lists.ozlabs.org, sparclinux-AT-vger.kernel.org, x86-AT-kernel.org | |
| Archive-link: | Article |
From: Mike Rapoport <rppt@linux.ibm.com> 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-d006-7d86-78a4... v5 changes: * use pairs of _map()/_unmap() functions instead of _map(..., int enable) as Vlastimil suggested 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@... v3 changes: * update arm64 changes to avoid regression, per Rick's comments * fix bisectability https://lore.kernel.org/lkml/20201101170815.9795-1-rppt@k... 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@... v1: https://lore.kernel.org/lkml/20201025101555.3057-1-rppt@k... Mike Rapoport (5): mm: introduce debug_pagealloc_{map,unmap}_pages() helpers slab: debug: split slab_kernel_map() to map and unmap variants 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 ++--- mm/slab.c | 26 ++++++++++--------- 20 files changed, 127 insertions(+), 65 deletions(-) -- 2.28.0