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Message-Id: <20201029161902.19272-1-rppt@kernel.org>
Date: Thu, 29 Oct 2020 18:18:58 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Albert Ou <aou@...s.berkeley.edu>,
Andy Lutomirski <luto@...nel.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Borislav Petkov <bp@...en8.de>,
Catalin Marinas <catalin.marinas@....com>,
Christian Borntraeger <borntraeger@...ibm.com>,
Christoph Lameter <cl@...ux.com>,
"David S. Miller" <davem@...emloft.net>,
Dave Hansen <dave.hansen@...ux.intel.com>,
David Hildenbrand <david@...hat.com>,
David Rientjes <rientjes@...gle.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
"H. Peter Anvin" <hpa@...or.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Ingo Molnar <mingo@...hat.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
"Kirill A. Shutemov" <kirill@...temov.name>,
Len Brown <len.brown@...el.com>,
Michael Ellerman <mpe@...erman.id.au>,
Mike Rapoport <rppt@...nel.org>,
Mike Rapoport <rppt@...ux.ibm.com>,
Palmer Dabbelt <palmer@...belt.com>,
Paul Mackerras <paulus@...ba.org>,
Paul Walmsley <paul.walmsley@...ive.com>,
Pavel Machek <pavel@....cz>, Pekka Enberg <penberg@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Thomas Gleixner <tglx@...utronix.de>,
Vasily Gorbik <gor@...ux.ibm.com>,
Will Deacon <will@...nel.org>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-mm@...ck.org, linux-pm@...r.kernel.org,
linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, sparclinux@...r.kernel.org,
x86@...nel.org
Subject: [PATCH v2 0/4] arch, mm: improve robustness of direct map manipulation
From: Mike Rapoport <rppt@...ux.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, it is updated to make direct map accesses there more
explicit.
[1] https://lore.kernel.org/lkml/2759b4bf-e1e3-d006-7d86-78a40348269d@redhat.com
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
v1:
https://lore.kernel.org/lkml/20201025101555.3057-1-rppt@kernel.org
Mike Rapoport (4):
mm: introduce debug_pagealloc_map_pages() helper
PM: hibernate: make direct map manipulations more explicit
arch, mm: restore dependency of __kernel_map_pages() of 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 | 35 +++++++++++++----------------
include/linux/set_memory.h | 5 +++++
kernel/power/snapshot.c | 30 +++++++++++++++++++++++--
mm/memory_hotplug.c | 3 +--
mm/page_alloc.c | 6 ++---
mm/slab.c | 8 +++----
20 files changed, 103 insertions(+), 58 deletions(-)
--
2.28.0
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