The static analyzer in GCC 10 spotted that in huge_pte_alloc() we may
pass a NULL pmdp into pte_alloc_map() when pmd_alloc() returns NULL:
| CC arch/arm64/mm/pageattr.o
| CC arch/arm64/mm/hugetlbpage.o
| from arch/arm64/mm/hugetlbpage.c:10:
| arch/arm64/mm/hugetlbpage.c: In function ‘huge_pte_alloc’:
| ./arch/arm64/include/asm/pgtable-types.h:28:24: warning: dereference of NULL ‘pmdp’ [CWE-690] [-Wanalyzer-null-dereference]
| ./arch/arm64/include/asm/pgtable.h:436:26: note: in expansion of macro ‘pmd_val’
| arch/arm64/mm/hugetlbpage.c:242:10: note: in expansion of macro ‘pte_alloc_map’
| |arch/arm64/mm/hugetlbpage.c:232:10:
| |./arch/arm64/include/asm/pgtable-types.h:28:24:
| ./arch/arm64/include/asm/pgtable.h:436:26: note: in expansion of macro ‘pmd_val’
| arch/arm64/mm/hugetlbpage.c:242:10: note: in expansion of macro ‘pte_alloc_map’
This can only occur when the kernel cannot allocate a page, and so is
unlikely to happen in practice before other systems start failing.
We can avoid this by bailing out if pmd_alloc() fails, as we do earlier
in the function if pud_alloc() fails.
Fixes: 66b3923a1a ("arm64: hugetlb: add support for PTE contiguous bit")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Kyrill Tkachov <kyrylo.tkachov@arm.com>
Cc: <stable@vger.kernel.org> # 4.5.x-
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Replace all open encoded contiguous huge page size computations with
available macro encodings CONT_PTE_SIZE and CONT_PMD_SIZE. There are other
instances where these macros are used in the file and this change makes it
consistently use the same mnemonic.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 655 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Let arm64 subscribe to the previously added framework in which
architecture can inform whether a given huge page size is supported for
migration. This just overrides the default function
arch_hugetlb_migration_supported() and enables migration for all
possible HugeTLB page sizes on arm64.
With this, HugeTLB migration support on arm64 now covers all possible
HugeTLB options.
CONT PTE PMD CONT PMD PUD
-------- --- -------- ---
4K: 64K 2M 32M 1G
16K: 2M 32M 1G
64K: 2M 512M 16G
Link: http://lkml.kernel.org/r/1545121450-1663-6-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add hstate for each supported hugepage size using arch initcall.
* no hugepage parameters
Without hugepage parameters, only a default hugepage size is
available for dynamic allocation. It's different, for example, from
x86_64 and sparc64 where all supported hugepage sizes are available.
* only default_hugepagesz= is specified and set not to HPAGE_SIZE
In spite of the fact that default_hugepagesz= is set to a valid
hugepage size, it's treated as unsupported and reverted to
HPAGE_SIZE. Such behaviour is also different from x86_64 and
sparc64.
Acked-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Tom Saeger <tom.saeger@oracle.com>
Signed-off-by: Dmitry Klochkov <dmitry.klochkov@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
For contiguous hugetlb, huge_ptep_set_access_flags performs a
get_clear_flush (which then flushes the TLBs) even when no change of ptes
is necessary.
Unfortunately, this behaviour can lead to back-to-back page faults being
generated when running with multiple threads that access the same
contiguous huge page.
Thread 1 | Thread 2
-----------------------------+------------------------------
hugetlb_fault |
huge_ptep_set_access_flags |
-> invalidate pte range | hugetlb_fault
continue processing | wait for hugetlb_fault_mutex
release mutex and return | huge_ptep_set_access_flags
| -> invalidate pte range
hugetlb_fault
...
This patch changes huge_ptep_set_access_flags s.t. we first read the
contiguous range of ptes (whilst preserving dirty information); the pte
range is only then invalidated where necessary and this prevents further
spurious page faults.
Fixes: d8bdcff287 ("arm64: hugetlb: Add break-before-make logic for contiguous entries")
Reported-by: Lei Zhang <zhang.lei@jp.fujitsu.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
In the contiguous bit hugetlb break-before-make code we assume that all
hugetlb pages are young.
In fact, remove_migration_pte is able to place an old hugetlb pte so
this assumption is not valid.
This patch fixes the contiguous hugetlb scanning code to preserve young
ptes.
Fixes: d8bdcff287 ("arm64: hugetlb: Add break-before-make logic for contiguous entries")
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Commit 2c4541e24c ("mm: use vma_init() to initialize VMAs on stack and
data segments") tried to initialize various left-over ad-hoc vma's
"properly", but actually made things worse for the temporary vma's used
for TLB flushing.
vma_init() doesn't actually initialize all of the vma, just a few
fields, so doing something like
- struct vm_area_struct vma = { .vm_mm = tlb->mm, };
+ struct vm_area_struct vma;
+
+ vma_init(&vma, tlb->mm);
was actually very bad: instead of having a nicely initialized vma with
every field but "vm_mm" zeroed, you'd have an entirely uninitialized vma
with only a couple of fields initialized. And they weren't even fields
that the code in question mostly cared about.
The flush_tlb_range() function takes a "struct vma" rather than a
"struct mm_struct", because a few architectures actually care about what
kind of range it is - being able to only do an ITLB flush if it's a
range that doesn't have data accesses enabled, for example. And all the
normal users already have the vma for doing the range invalidation.
But a few people want to call flush_tlb_range() with a range they just
made up, so they also end up using a made-up vma. x86 just has a
special "flush_tlb_mm_range()" function for this, but other
architectures (arm and ia64) do the "use fake vma" thing instead, and
thus got caught up in the vma_init() changes.
At the same time, the TLB flushing code really doesn't care about most
other fields in the vma, so vma_init() is just unnecessary and
pointless.
This fixes things by having an explicit "this is just an initializer for
the TLB flush" initializer macro, which is used by the arm/arm64/ia64
people who mis-use this interface with just a dummy vma.
Fixes: 2c4541e24c ("mm: use vma_init() to initialize VMAs on stack and data segments")
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make sure to initialize all VMAs properly, not only those which come
from vm_area_cachep.
Link: http://lkml.kernel.org/r/20180724121139.62570-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In many cases, page tables can be accessed concurrently by either another
CPU (due to things like fast gup) or by the hardware page table walker
itself, which may set access/dirty bits. In such cases, it is important
to use READ_ONCE/WRITE_ONCE when accessing page table entries so that
entries cannot be torn, merged or subject to apparent loss of coherence
due to compiler transformations.
Whilst there are some scenarios where this cannot happen (e.g. pinned
kernel mappings for the linear region), the overhead of using READ_ONCE
/WRITE_ONCE everywhere is minimal and makes the code an awful lot easier
to reason about. This patch consistently uses these macros in the arch
code, as well as explicitly namespacing pointers to page table entries
from the entries themselves by using adopting a 'p' suffix for the former
(as is sometimes used elsewhere in the kernel source).
Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Replace a lot of if statements with switch and case labels to make it
much clearer which huge page sizes are supported.
Also, we prevent PUD_SIZE from being used on systems not running with
4KB PAGE_SIZE. Before if one supplied PUD_SIZE in these circumstances,
then unusuable huge page sizes would be in use.
Fixes: 084bd29810 ("ARM64: mm: HugeTLB support.")
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
also known as -
Revert "Revert "Revert "commit 66b3923a1a ("arm64: hugetlb: add
support for PTE contiguous bit")"""
Now that our hugetlb implementation is compliant with the
break-before-make requirements of the architecture and we have addressed
some of the issues in core code required for properly dealing with
hardware poisoning of contiguous hugepages let's re-enable support for
contiguous hugepages.
This reverts commit 6ae979ab39.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The default implementation of set_huge_swap_pte_at() does not support
hugepages consisting of contiguous ptes. Override it to add support for
contiguous hugepages.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The default huge_pte_clear() implementation does not clear contiguous
page table entries when it encounters contiguous hugepages that are
supported on arm64.
Fix this by overriding the default implementation to clear all the
entries associated with contiguous hugepages.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
huge_pte_offset() was updated to correctly handle swap entries for
hugepages. With the addition of the size parameter, it is now possible
to disambiguate whether the request is for a regular hugepage or a
contiguous hugepage.
Fix huge_pte_offset() for contiguous hugepages by using the size to find
the correct page table entry.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
It has become apparent that one has to take special care when modifying
attributes of memory mappings that employ the contiguous bit.
Both the requirement and the architecturally correct "Break-Before-Make"
technique of updating contiguous entries can be found described in:
ARM DDI 0487A.k_iss10775, "Misprogramming of the Contiguous bit",
page D4-1762.
The huge pte accessors currently replace the attributes of contiguous
pte entries in place thus can, on certain platforms, lead to TLB
conflict aborts or even erroneous results returned from TLB lookups.
This patch adds two helper functions -
* get_clear_flush(.) - clears a contiguous entry and returns the head
pte (whilst taking care to retain dirty bit information that could
have been modified by DBM).
* clear_flush(.) that clears a contiguous entry
A tlb invalidate is performed to then ensure that there is no
possibility of multiple tlb entries being present for the same region.
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
(Added helper clear_flush(), updated commit log, and some cleanup)
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
[catalin.marinas@arm.com: remove CONFIG_ARM64_HW_AFDBM check]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch aims to re-structure the huge pte accessors without affecting
their functionality. Control flow is changed to reduce indentation and
expanded use is made of post for loop variable modification.
It is then much easier to add break-before-make semantics in a subsequent
patch.
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Rather than xor pte bits in various places, use this helper function.
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds a WARN_ON to set_huge_pte_at as the accessor assumes
that entries to be written down are all present. (There are separate
accessors to clear huge ptes).
We will need to handle the !pte_present case where memory offlining
is used on hugetlb pages. swap and migration entries will be supplied
to set_huge_pte_at in this case.
Cc: David Woods <dwoods@mellanox.com>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
A poisoned or migrated hugepage is stored as a swap entry in the page
tables. On architectures that support hugepages consisting of
contiguous page table entries (such as on arm64) this leads to ambiguity
in determining the page table entry to return in huge_pte_offset() when
a poisoned entry is encountered.
Let's remove the ambiguity by adding a size parameter to convey
additional information about the requested address. Also fixup the
definition/usage of huge_pte_offset() throughout the tree.
Link: http://lkml.kernel.org/r/20170522133604.11392-4-punit.agrawal@arm.com
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com> (odd fixer:METAG ARCHITECTURE)
Cc: Ralf Baechle <ralf@linux-mips.org> (supporter:MIPS)
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't need to call huge_ptep_offset as our accessors are already
supplied with the pte_t *. This patch removes those spurious calls.
[punit.agrawal@arm.com: resolve rebase conflicts due to patch re-ordering]
Link: http://lkml.kernel.org/r/20170524115409.31309-3-punit.agrawal@arm.com
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Support for contiguous pte hugepages", v4.
This patchset updates the hugetlb code to fix issues arising from
contiguous pte hugepages (such as on arm64). Compared to v3, This
version addresses a build failure on arm64 by including two cleanup
patches. Other than the arm64 cleanups, the rest are generic code
changes. The remaining arm64 support based on these patches will be
posted separately. The patches are based on v4.12-rc2. Previous
related postings can be found at [0], [1], [2], and [3].
The patches fall into three categories -
* Patch 1-2 - arm64 cleanups required to greatly simplify changing
huge_pte_offset() prototype in Patch 5.
Catalin, Will - are you happy for these patches to go via mm?
* Patches 3-4 address issues with gup
* Patches 5-8 relate to passing a size argument to hugepage helpers to
disambiguate the size of the referred page. These changes are
required to enable arch code to properly handle swap entries for
contiguous pte hugepages.
The changes to huge_pte_offset() (patch 5) touch multiple
architectures but I've managed to minimise these changes for the
other affected functions - huge_pte_clear() and set_huge_pte_at().
These patches gate the enabling of contiguous hugepages support on arm64
which has been requested for systems using !4k page granule.
The ARM64 architecture supports two flavours of hugepages -
* Block mappings at the pud/pmd level
These are regular hugepages where a pmd or a pud page table entry
points to a block of memory. Depending on the PAGE_SIZE in use the
following size of block mappings are supported -
PMD PUD
--- ---
4K: 2M 1G
16K: 32M
64K: 512M
For certain applications/usecases such as HPC and large enterprise
workloads, folks are using 64k page size but the minimum hugepage size
of 512MB isn't very practical.
To overcome this ...
* Using the Contiguous bit
The architecture provides a contiguous bit in the translation table
entry which acts as a hint to the mmu to indicate that it is one of a
contiguous set of entries that can be cached in a single TLB entry.
We use the contiguous bit in Linux to increase the mapping size at the
pmd and pte (last) level.
The number of supported contiguous entries varies by page size and
level of the page table.
Using the contiguous bit allows additional hugepage sizes -
CONT PTE PMD CONT PMD PUD
-------- --- -------- ---
4K: 64K 2M 32M 1G
16K: 2M 32M 1G
64K: 2M 512M 16G
Of these, 64K with 4K and 2M with 64K pages have been explicitly
requested by a few different users.
Entries with the contiguous bit set are required to be modified all
together - which makes things like memory poisoning and migration
impossible to do correctly without knowing the size of hugepage being
dealt with - the reason for adding size parameter to a few of the
hugepage helpers in this series.
This patch (of 8):
As we regularly check for contiguous pte's in the huge accessors, remove
this extra check from find_num_contig.
[punit.agrawal@arm.com: resolve rebase conflicts due to patch re-ordering]
Link: http://lkml.kernel.org/r/20170524115409.31309-2-punit.agrawal@arm.com
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When memory failure is enabled, a poisoned hugepage pte is marked as a
swap entry. huge_pte_offset() does not return the poisoned page table
entries when it encounters PUD/PMD hugepages.
This behaviour of huge_pte_offset() leads to error such as below when
munmap is called on poisoned hugepages.
[ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074.
Fix huge_pte_offset() to return the poisoned pte which is then
appropriately handled by the generic layer code.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Tested-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The use of the contiguous bit by our hugetlb implementation violates
the break-before-make requirements of the architecture and can lead to
silent data corruption or TLB conflict aborts. Once again, disable these
hugetlb sizes whilst it gets worked out.
This reverts commit ab2e1b8923.
Conflicts:
arch/arm64/mm/hugetlbpage.c
Signed-off-by: Will Deacon <will.deacon@arm.com>
In current code, the @changed always returns the last one's status for
the huge page with the contiguous bit set. This is really not what we
want. Even one of the PTEs is changed, we should tell it to the caller.
This patch fixes this issue.
Fixes: 66b3923a1a ("arm64: hugetlb: add support for PTE contiguous bit")
Cc: <stable@vger.kernel.org> # 4.5.x-
Signed-off-by: Huang Shijie <shijie.huang@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The libhugetlbfs meets several failures since the following functions
do not use the correct address:
huge_ptep_get_and_clear()
huge_ptep_set_access_flags()
huge_ptep_set_wrprotect()
huge_ptep_clear_flush()
This patch fixes the wrong address for them.
Signed-off-by: Huang Shijie <shijie.huang@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The find_num_contig() will return 1 when the pmd is not present.
It will cause a kernel dead loop in the following scenaro:
1.) pmd entry is not present.
2.) the page fault occurs:
... hugetlb_fault() --> hugetlb_no_page() --> set_huge_pte_at()
3.) set_huge_pte_at() will only set the first PMD entry, since the
find_num_contig just return 1 in this case. So the PMD entries
are all empty except the first one.
4.) when kernel accesses the address mapped by the second PMD entry,
a new page fault occurs:
... hugetlb_fault() --> huge_ptep_set_access_flags()
The second PMD entry is still empty now.
5.) When the kernel returns, the access will cause a page fault again.
The kernel will run like the "4)" above.
We will see a dead loop since here.
The dead loop is caught in the 32M hugetlb page (2M PMD + Contiguous bit).
This patch removes wrong pmd check, and fixes this dead loop.
This patch also removes the redundant checks for PGD/PUD in
the find_num_contig().
Acked-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Huang Shijie <shijie.huang@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The default hugepage size when 64K pages are enabled is set to 2MB using
the contiguous PTE bit. The add_default_hugepagesz(), however, uses
CONT_PMD_SHIFT instead of CONT_PTE_SHIFT. There is no functional change
since the values are the same.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This reverts commit ff7925848b.
Now that the contiguous-hint hugetlb regression has been debugged and
fixed upstream by 66ee95d16a ("mm: exclude HugeTLB pages from THP
page_mapped() logic"), we can revert the previous partial revert of this
feature.
Signed-off-by: Will Deacon <will.deacon@arm.com>
There are few things about *pte_alloc*() helpers worth cleaning up:
- 'vma' argument is unused, let's drop it;
- most __pte_alloc() callers do speculative check for pmd_none(),
before taking ptl: let's introduce pte_alloc() macro which does
the check.
The only direct user of __pte_alloc left is userfaultfd, which has
different expectation about atomicity wrt pmd.
- pte_alloc_map() and pte_alloc_map_lock() are redefined using
pte_alloc().
[sudeep.holla@arm.com: fix build for arm64 hugetlbpage]
[sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 66b3923a1a ("arm64: hugetlb: add support for PTE contiguous bit")
introduced support for huge pages using the contiguous bit in the PTE
as opposed to block mappings, which may be slightly unwieldy (512M) in
64k page configurations.
Unfortunately, this support has resulted in some late regressions when
running the libhugetlbfs test suite with 64k pages and CONFIG_DEBUG_VM
as a result of a BUG:
| readback (2M: 64): ------------[ cut here ]------------
| kernel BUG at fs/hugetlbfs/inode.c:446!
| Internal error: Oops - BUG: 0 [#1] SMP
| Modules linked in:
| CPU: 7 PID: 1448 Comm: readback Not tainted 4.5.0-rc7 #148
| Hardware name: linux,dummy-virt (DT)
| task: fffffe0040964b00 ti: fffffe00c2668000 task.ti: fffffe00c2668000
| PC is at remove_inode_hugepages+0x44c/0x480
| LR is at remove_inode_hugepages+0x264/0x480
Rather than revert the entire patch, simply avoid advertising the
contiguous huge page sizes for now while people are actively working on
a fix. This patch can then be reverted once things have been sorted out.
Cc: David Woods <dwoods@ezchip.com>
Reported-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The arm64 MMU supports a Contiguous bit which is a hint that the TTE
is one of a set of contiguous entries which can be cached in a single
TLB entry. Supporting this bit adds new intermediate huge page sizes.
The set of huge page sizes available depends on the base page size.
Without using contiguous pages the huge page sizes are as follows.
4KB: 2MB 1GB
64KB: 512MB
With a 4KB granule, the contiguous bit groups together sets of 16 pages
and with a 64KB granule it groups sets of 32 pages. This enables two new
huge page sizes in each case, so that the full set of available sizes
is as follows.
4KB: 64KB 2MB 32MB 1GB
64KB: 2MB 512MB 16GB
If a 16KB granule is used then the contiguous bit groups 128 pages
at the PTE level and 32 pages at the PMD level.
If the base page size is set to 64KB then 2MB pages are enabled by
default. It is possible in the future to make 2MB the default huge
page size for both 4KB and 64KB granules.
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Reviewed-by: Steve Capper <steve.capper@linaro.org>
Signed-off-by: David Woods <dwoods@ezchip.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Remove paragraph about writing to the Free Software Foundation's
mailing address from GPL notice.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
- suspicious RCU usage warning
- BPF (out of bounds array read and endianness conversion)
- perf (of_node usage after of_node_put, cpu_pmu->plat_device
assignment)
- huge pmd/pud check for value 0
- rate-limiting should only take unhandled signals into account
Clean-up:
- incorrect use of pgprot_t type
- unused header include
- __init annotation to arm_cpuidle_init
- pr_debug instead of pr_error for disabled GICC entries in ACPI/MADT
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes (and cleanups) from Catalin Marinas:
"Various arm64 fixes:
- suspicious RCU usage warning
- BPF (out of bounds array read and endianness conversion)
- perf (of_node usage after of_node_put, cpu_pmu->plat_device
assignment)
- huge pmd/pud check for value 0
- rate-limiting should only take unhandled signals into account
Clean-up:
- incorrect use of pgprot_t type
- unused header include
- __init annotation to arm_cpuidle_init
- pr_debug instead of pr_error for disabled GICC entries in
ACPI/MADT"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Fix show_unhandled_signal_ratelimited usage
ARM64 / SMP: Switch pr_err() to pr_debug() for disabled GICC entry
arm64: cpuidle: add __init section marker to arm_cpuidle_init
arm64: Don't report clear pmds and puds as huge
arm64: perf: fix unassigned cpu_pmu->plat_device when probing PMU PPIs
arm64: perf: Don't use of_node after putting it
arm64: fix incorrect use of pgprot_t variable
arm64/hw_breakpoint.c: remove unnecessary header
arm64: bpf: fix endianness conversion bugs
arm64: bpf: fix out-of-bounds read in bpf2a64_offset()
ARM64: smp: Fix suspicious RCU usage with ipi tracepoints
The current pmd_huge() and pud_huge() functions simply check if the table
bit is not set and reports the entries as huge in that case. This is
counter-intuitive as a clear pmd/pud cannot also be a huge pmd/pud, and
it is inconsistent with at least arm and x86.
To prevent others from making the same mistake as me in looking at code
that calls these functions and to fix an issue with KVM on arm64 that
causes memory corruption due to incorrect page reference counting
resulting from this mistake, let's change the behavior.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Fixes: 084bd29810 ("ARM64: mm: HugeTLB support.")
Cc: <stable@vger.kernel.org> # 3.11+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Currently we have many duplicates in definitions of huge_pmd_unshare. In
all architectures this function just returns 0 when
CONFIG_ARCH_WANT_HUGE_PMD_SHARE is N.
This patch puts the default implementation in mm/hugetlb.c and lets these
architectures use the common code.
Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Rientjes <rientjes@google.com>
Cc: James Yang <James.Yang@freescale.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we have many duplicates in definitions around
follow_huge_addr(), follow_huge_pmd(), and follow_huge_pud(), so this
patch tries to remove the m. The basic idea is to put the default
implementation for these functions in mm/hugetlb.c as weak symbols
(regardless of CONFIG_ARCH_WANT_GENERAL_HUGETL B), and to implement
arch-specific code only when the arch needs it.
For follow_huge_addr(), only powerpc and ia64 have their own
implementation, and in all other architectures this function just returns
ERR_PTR(-EINVAL). So this patch sets returning ERR_PTR(-EINVAL) as
default.
As for follow_huge_(pmd|pud)(), if (pmd|pud)_huge() is implemented to
always return 0 in your architecture (like in ia64 or sparc,) it's never
called (the callsite is optimized away) no matter how implemented it is.
So in such architectures, we don't need arch-specific implementation.
In some architecture (like mips, s390 and tile,) their current
arch-specific follow_huge_(pmd|pud)() are effectively identical with the
common code, so this patch lets these architecture use the common code.
One exception is metag, where pmd_huge() could return non-zero but it
expects follow_huge_pmd() to always return NULL. This means that we need
arch-specific implementation which returns NULL. This behavior looks
strange to me (because non-zero pmd_huge() implies that the architecture
supports PMD-based hugepage, so follow_huge_pmd() can/should return some
relevant value,) but that's beyond this cleanup patch, so let's keep it.
Justification of non-trivial changes:
- in s390, follow_huge_pmd() checks !MACHINE_HAS_HPAGE at first, and this
patch removes the check. This is OK because we can assume MACHINE_HAS_HPAGE
is true when follow_huge_pmd() can be called (note that pmd_huge() has
the same check and always returns 0 for !MACHINE_HAS_HPAGE.)
- in s390 and mips, we use HPAGE_MASK instead of PMD_MASK as done in common
code. This patch forces these archs use PMD_MASK, but it's OK because
they are identical in both archs.
In s390, both of HPAGE_SHIFT and PMD_SHIFT are 20.
In mips, HPAGE_SHIFT is defined as (PAGE_SHIFT + PAGE_SHIFT - 3) and
PMD_SHIFT is define as (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3), but
PTE_ORDER is always 0, so these are identical.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs. So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.
Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following happens when trying to run a kvm guest on a kernel
configured for 64k pages. This doesn't happen with 4k pages:
BUG: failure at include/linux/mm.h:297/put_page_testzero()!
Kernel panic - not syncing: BUG!
CPU: 2 PID: 4228 Comm: qemu-system-aar Tainted: GF 3.13.0-0.rc7.31.sa2.k32v1.aarch64.debug #1
Call trace:
[<fffffe0000096034>] dump_backtrace+0x0/0x16c
[<fffffe00000961b4>] show_stack+0x14/0x1c
[<fffffe000066e648>] dump_stack+0x84/0xb0
[<fffffe0000668678>] panic+0xf4/0x220
[<fffffe000018ec78>] free_reserved_area+0x0/0x110
[<fffffe000018edd8>] free_pages+0x50/0x88
[<fffffe00000a759c>] kvm_free_stage2_pgd+0x30/0x40
[<fffffe00000a5354>] kvm_arch_destroy_vm+0x18/0x44
[<fffffe00000a1854>] kvm_put_kvm+0xf0/0x184
[<fffffe00000a1938>] kvm_vm_release+0x10/0x1c
[<fffffe00001edc1c>] __fput+0xb0/0x288
[<fffffe00001ede4c>] ____fput+0xc/0x14
[<fffffe00000d5a2c>] task_work_run+0xa8/0x11c
[<fffffe0000095c14>] do_notify_resume+0x54/0x58
In arch/arm/kvm/mmu.c:unmap_range(), we end up doing an extra put_page()
on the stage2 pgd which leads to the BUG in put_page_testzero(). This
happens because a pud_huge() test in unmap_range() returns true when it
should always be false with 2-level pages tables used by 64k pages.
This patch removes support for huge puds if 2-level pagetables are
being used.
Signed-off-by: Mark Salter <msalter@redhat.com>
[catalin.marinas@arm.com: removed #ifndef around PUD_SIZE check]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org> # v3.11+
Currently hugepage migration works well only for pmd-based hugepages
(mainly due to lack of testing,) so we had better not enable migration of
other levels of hugepages until we are ready for it.
Some users of hugepage migration (mbind, move_pages, and migrate_pages) do
page table walk and check pud/pmd_huge() there, so they are safe. But the
other users (softoffline and memory hotremove) don't do this, so without
this patch they can try to migrate unexpected types of hugepages.
To prevent this, we introduce hugepage_migration_support() as an
architecture dependent check of whether hugepage are implemented on a pmd
basis or not. And on some architecture multiple sizes of hugepages are
available, so hugepage_migration_support() also checks hugepage size.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add huge page support to ARM64, different huge page sizes are
supported depending on the size of normal pages:
PAGE_SIZE is 4KB:
2MB - (pmds) these can be allocated at any time.
1024MB - (puds) usually allocated on bootup with the command line
with something like: hugepagesz=1G hugepages=6
PAGE_SIZE is 64KB:
512MB - (pmds) usually allocated on bootup via command line.
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
