linux.git/arch/arm/include/asm/pgtable-3level.h, branch v3.16.81

arm: drop L_PTE_FILE and pte_file()-related helpers

2018-10-03T03:09:53+00:00

commit b007ea798f5c568d3f464d37288220ef570f062c upstream.

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

This patch also adjust __SWP_TYPE_SHIFT, effectively increase size of
possible swap file to 128G.

Signed-off-by: Kirill A. Shutemov 
Cc: Russell King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

ARM: 8579/1: mm: Fix definition of pmd_mknotpresent

2016-08-22T21:38:14+00:00

commit 56530f5d2ddc9b9fade7ef8db9cb886e9dc689b5 upstream.

Currently pmd_mknotpresent will use a zero entry to respresent an
invalidated pmd.

Unfortunately this definition clashes with pmd_none, thus it is
possible for a race condition to occur if zap_pmd_range sees pmd_none
whilst __split_huge_pmd_locked is running too with pmdp_invalidate
just called.

This patch fixes the race condition by modifying pmd_mknotpresent to
create non-zero faulting entries (as is done in other architectures),
removing the ambiguity with pmd_none.

[catalin.marinas@arm.com: using L_PMD_SECT_VALID instead of PMD_TYPE_SECT]

Fixes: 8d9625070073 ("ARM: mm: Transparent huge page support for LPAE systems.")
Reported-by: Kirill A. Shutemov 
Acked-by: Will Deacon 
Cc: Russell King 
Signed-off-by: Steve Capper 
Signed-off-by: Catalin Marinas 
Signed-off-by: Russell King 
[bwh: Backported to 3.16: also convert from a macro to a function, as done
 earlier upstream]
Signed-off-by: Ben Hutchings

ARM: 8578/1: mm: ensure pmd_present only checks the valid bit

2016-08-22T21:38:14+00:00

commit 624531886987f0f1b5d01fb598034d039198e090 upstream.

In a subsequent patch, pmd_mknotpresent will clear the valid bit of the
pmd entry, resulting in a not-present entry from the hardware's
perspective. Unfortunately, pmd_present simply checks for a non-zero pmd
value and will therefore continue to return true even after a
pmd_mknotpresent operation. Since pmd_mknotpresent is only used for
managing huge entries, this is only an issue for the 3-level case.

This patch fixes the 3-level pmd_present implementation to take into
account the valid bit. For bisectability, the change is made before the
fix to pmd_mknotpresent.

[catalin.marinas@arm.com: comment update regarding pmd_mknotpresent patch]

Fixes: 8d9625070073 ("ARM: mm: Transparent huge page support for LPAE systems.")
Cc: Russell King 
Cc: Steve Capper 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas 
Signed-off-by: Russell King 
Signed-off-by: Ben Hutchings

ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE

2014-12-04T09:42:17+00:00

commit ded9477984690d026e46dd75e8157392cea3f13f upstream.

For LPAE, we have the following means for encoding writable or dirty
ptes:
                              L_PTE_DIRTY       L_PTE_RDONLY
    !pte_dirty && !pte_write        0               1
    !pte_dirty && pte_write         0               1
    pte_dirty && !pte_write         1               1
    pte_dirty && pte_write          1               0

So we can't distinguish between writeable clean ptes and read only
ptes. This can cause problems with ptes being incorrectly flagged as
read only when they are writeable but not dirty.

This patch renumbers L_PTE_RDONLY from AP[2] to a software bit #58,
and adds additional logic to set AP[2] whenever the pte is read only
or not dirty. That way we can distinguish between clean writeable ptes
and read only ptes.

HugeTLB pages will use this new logic automatically.

We need to add some logic to Transparent HugePages to ensure that they
correctly interpret the revised pgprot permissions (L_PTE_RDONLY has
moved and no longer matches PMD_SECT_AP2). In the process of revising
THP, the names of the PMD software bits have been prefixed with L_ to
make them easier to distinguish from their hardware bit counterparts.

Signed-off-by: Steve Capper 
Reviewed-by: Will Deacon 
Signed-off-by: Russell King 
Cc: Hou Pengyang 
Signed-off-by: Luis Henriques

ARM: 8108/1: mm: Introduce {pte,pmd}_isset and {pte,pmd}_isclear

2014-12-04T09:41:49+00:00

commit f2950706871c4b6e8c0f0d7c3f62d35930b8de63 upstream.

Long descriptors on ARM are 64 bits, and some pte functions such as
pte_dirty return a bitwise-and of a flag with the pte value. If the
flag to be tested resides in the upper 32 bits of the pte, then we run
into the danger of the result being dropped if downcast.

For example:
	gather_stats(page, md, pte_dirty(*pte), 1);
where pte_dirty(*pte) is downcast to an int.

This patch introduces a new macro pte_isset which performs the bitwise
and, then performs a double logical invert (where needed) to ensure
predictable downcasting. The logical inverse pte_isclear is also
introduced.

Equivalent pmd functions for Transparent HugePages have also been
added.

Signed-off-by: Steve Capper 
Reviewed-by: Will Deacon 
Signed-off-by: Russell King 
Cc: Hou Pengyang 
Signed-off-by: Luis Henriques

ARM: 7950/1: mm: Fix stage-2 device memory attributes

2014-02-10T11:44:05+00:00

The stage-2 memory attributes are distinct from the Hyp memory
attributes and the Stage-1 memory attributes.  We were using the stage-1
memory attributes for stage-2 mappings causing device mappings to be
mapped as normal memory.  Add the S2 equivalent defines for memory
attributes and fix the comments explaining the defines while at it.

Add a prot_pte_s2 field to the mem_type struct and fill out the field
for device mappings accordingly.

Cc: 	[3.9+]
Acked-by: Marc Zyngier 
Acked-by: Catalin Marinas 
Signed-off-by: Christoffer Dall 
Signed-off-by: Russell King

ARM: add support to dump the kernel page tables

2013-12-11T09:53:13+00:00

This patch allows the kernel page tables to be dumped via a debugfs file,
allowing kernel developers to check the layout of the kernel page tables
and the verify the various permissions and type settings.

Signed-off-by: Russell King

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2013-11-15T04:51:36+00:00

Pull KVM changes from Paolo Bonzini:
 "Here are the 3.13 KVM changes.  There was a lot of work on the PPC
  side: the HV and emulation flavors can now coexist in a single kernel
  is probably the most interesting change from a user point of view.

  On the x86 side there are nested virtualization improvements and a few
  bugfixes.

  ARM got transparent huge page support, improved overcommit, and
  support for big endian guests.

  Finally, there is a new interface to connect KVM with VFIO.  This
  helps with devices that use NoSnoop PCI transactions, letting the
  driver in the guest execute WBINVD instructions.  This includes some
  nVidia cards on Windows, that fail to start without these patches and
  the corresponding userspace changes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits)
  kvm, vmx: Fix lazy FPU on nested guest
  arm/arm64: KVM: PSCI: propagate caller endianness to the incoming vcpu
  arm/arm64: KVM: MMIO support for BE guest
  kvm, cpuid: Fix sparse warning
  kvm: Delete prototype for non-existent function kvm_check_iopl
  kvm: Delete prototype for non-existent function complete_pio
  hung_task: add method to reset detector
  pvclock: detect watchdog reset at pvclock read
  kvm: optimize out smp_mb after srcu_read_unlock
  srcu: API for barrier after srcu read unlock
  KVM: remove vm mmap method
  KVM: IOMMU: hva align mapping page size
  KVM: x86: trace cpuid emulation when called from emulator
  KVM: emulator: cleanup decode_register_operand() a bit
  KVM: emulator: check rex prefix inside decode_register()
  KVM: x86: fix emulation of "movzbl %bpl, %eax"
  kvm_host: typo fix
  KVM: x86: emulate SAHF instruction
  MAINTAINERS: add tree for kvm.git
  Documentation/kvm: add a 00-INDEX file
  ...

ARM: 7858/1: mm: make UACCESS_WITH_MEMCPY huge page aware

2013-10-29T11:06:15+00:00

The memory pinning code in uaccess_with_memcpy.c does not check
for HugeTLB or THP pmds, and will enter an infinite loop should
a __copy_to_user or __clear_user occur against a huge page.

This patch adds detection code for huge pages to pin_page_for_write.
As this code can be executed in a fast path it refers to the actual
pmds rather than the vma. If a HugeTLB or THP is found (they have
the same pmd representation on ARM), the page table spinlock is
taken to prevent modification whilst the page is pinned.

On ARM, huge pages are only represented as pmds, thus no huge pud
checks are performed. (For huge puds one would lock the page table
in a similar manner as in the pmd case).

Two helper functions are introduced; pmd_thp_or_huge will check
whether or not a page is huge or transparent huge (which have the
same pmd layout on ARM), and pmd_hugewillfault will detect whether
or not a page fault will occur on write to the page.

Running the following test (with the chunking from read_zero
removed):
 $ dd if=/dev/zero of=/dev/null bs=10M count=1024
Gave:  2.3 GB/s backed by normal pages,
       2.9 GB/s backed by huge pages,
       5.1 GB/s backed by huge pages, with page mask=HPAGE_MASK.

After some discussion, it was decided not to adopt the HPAGE_MASK,
as this would have a significant detrimental effect on the overall
system latency due to page_table_lock being held for too long.
This could be revisited if split huge page locks are adopted.

Signed-off-by: Steve Capper 
Reviewed-by: Nicolas Pitre 
Signed-off-by: Russell King

KVM: ARM: Support hugetlbfs backed huge pages

2013-10-18T00:06:20+00:00

Support huge pages in KVM/ARM and KVM/ARM64.  The pud_huge checking on
the unmap path may feel a bit silly as the pud_huge check is always
defined to false, but the compiler should be smart about this.

Note: This deals only with VMAs marked as huge which are allocated by
users through hugetlbfs only.  Transparent huge pages can only be
detected by looking at the underlying pages (or the page tables
themselves) and this patch so far simply maps these on a page-by-page
level in the Stage-2 page tables.

Cc: Catalin Marinas 
Cc: Russell King 
Acked-by: Catalin Marinas 
Acked-by: Marc Zyngier 
Signed-off-by: Christoffer Dall