From: Mike Rapoport <rppt@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-mm@kvack.org, Paul Mackerras <paulus@samba.org>,
Pavel Machek <pavel@ucw.cz>, "H. Peter Anvin" <hpa@zytor.com>,
sparclinux@vger.kernel.org, Christoph Lameter <cl@linux.com>,
Will Deacon <will@kernel.org>,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
x86@kernel.org, Mike Rapoport <rppt@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Ingo Molnar <mingo@redhat.com>,
linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Len Brown <len.brown@intel.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Vasily Gorbik <gor@linux.ibm.com>,
linux-pm@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
David Rientjes <rientjes@google.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Thomas Gleixner <tglx@linutronix.de>,
Vlastimil Babka <vbabka@suse.cz>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kernel@vger.kernel.org, Pekka Enberg <penberg@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
linuxppc-dev@lists.ozlabs.org,
"David S. Miller" <davem@davemloft.net>,
Mike Rapoport <rppt@kernel.org>
Subject: [PATCH v6 0/4] arch, mm: improve robustness of direct map manipulation
Date: Mon, 9 Nov 2020 18:24:11 +0200 [thread overview]
Message-ID: <20201109162415.13764-1-rppt@kernel.org> (raw)
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-d006-7d86-78a40348269d@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
next reply other threads:[~2020-11-09 16:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-09 16:24 Mike Rapoport [this message]
2020-11-09 16:24 ` [PATCH v6 1/4] mm: introduce debug_pagealloc_{map, unmap}_pages() helpers Mike Rapoport
2020-11-09 16:24 ` [PATCH v6 2/4] PM: hibernate: make direct map manipulations more explicit Mike Rapoport
2020-11-09 16:24 ` [PATCH v6 3/4] arch, mm: restore dependency of __kernel_map_pages() on DEBUG_PAGEALLOC Mike Rapoport
2020-11-09 16:24 ` [PATCH v6 4/4] arch, mm: make kernel_page_present() always available Mike Rapoport
2020-11-09 16:47 ` [PATCH v6 0/4] arch, mm: improve robustness of direct map manipulation Mike Rapoport
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