linux.git/arch/arm/include, branch v4.13

KVM: update to new mmu_notifier semantic v2

2017-08-31T23:13:00+00:00

Calls to mmu_notifier_invalidate_page() were replaced by calls to
mmu_notifier_invalidate_range() and are now bracketed by calls to
mmu_notifier_invalidate_range_start()/end()

Remove now useless invalidate_page callback.

Changed since v1 (Linus Torvalds)
    - remove now useless kvm_arch_mmu_notifier_invalidate_page()

Signed-off-by: Jérôme Glisse 
Tested-by: Mike Galbraith 
Tested-by: Adam Borowski 
Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: kvm@vger.kernel.org
Cc: Kirill A. Shutemov 
Cc: Andrew Morton 
Cc: Andrea Arcangeli 
Signed-off-by: Linus Torvalds

mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem

2017-08-10T22:54:07+00:00

Nadav reported parallel MADV_DONTNEED on same range has a stale TLB
problem and Mel fixed it[1] and found same problem on MADV_FREE[2].

Quote from Mel Gorman:
 "The race in question is CPU 0 running madv_free and updating some PTEs
  while CPU 1 is also running madv_free and looking at the same PTEs.
  CPU 1 may have writable TLB entries for a page but fail the pte_dirty
  check (because CPU 0 has updated it already) and potentially fail to
  flush.

  Hence, when madv_free on CPU 1 returns, there are still potentially
  writable TLB entries and the underlying PTE is still present so that a
  subsequent write does not necessarily propagate the dirty bit to the
  underlying PTE any more. Reclaim at some unknown time at the future
  may then see that the PTE is still clean and discard the page even
  though a write has happened in the meantime. I think this is possible
  but I could have missed some protection in madv_free that prevents it
  happening."

This patch aims for solving both problems all at once and is ready for
other problem with KSM, MADV_FREE and soft-dirty story[3].

TLB batch API(tlb_[gather|finish]_mmu] uses [inc|dec]_tlb_flush_pending
and mmu_tlb_flush_pending so that when tlb_finish_mmu is called, we can
catch there are parallel threads going on.  In that case, forcefully,
flush TLB to prevent for user to access memory via stale TLB entry
although it fail to gather page table entry.

I confirmed this patch works with [4] test program Nadav gave so this
patch supersedes "mm: Always flush VMA ranges affected by zap_page_range
v2" in current mmotm.

NOTE:

This patch modifies arch-specific TLB gathering interface(x86, ia64,
s390, sh, um).  It seems most of architecture are straightforward but
s390 need to be careful because tlb_flush_mmu works only if
mm->context.flush_mm is set to non-zero which happens only a pte entry
really is cleared by ptep_get_and_clear and friends.  However, this
problem never changes the pte entries but need to flush to prevent
memory access from stale tlb.

[1] http://lkml.kernel.org/r/20170725101230.5v7gvnjmcnkzzql3@techsingularity.net
[2] http://lkml.kernel.org/r/20170725100722.2dxnmgypmwnrfawp@suse.de
[3] http://lkml.kernel.org/r/BD3A0EBE-ECF4-41D4-87FA-C755EA9AB6BD@gmail.com
[4] https://patchwork.kernel.org/patch/9861621/

[minchan@kernel.org: decrease tlb flush pending count in tlb_finish_mmu]
  Link: http://lkml.kernel.org/r/20170808080821.GA31730@bbox
Link: http://lkml.kernel.org/r/20170802000818.4760-7-namit@vmware.com
Signed-off-by: Minchan Kim 
Signed-off-by: Nadav Amit 
Reported-by: Nadav Amit 
Reported-by: Mel Gorman 
Acked-by: Mel Gorman 
Cc: Ingo Molnar 
Cc: Russell King 
Cc: Tony Luck 
Cc: Martin Schwidefsky 
Cc: "David S. Miller" 
Cc: Heiko Carstens 
Cc: Yoshinori Sato 
Cc: Jeff Dike 
Cc: Andrea Arcangeli 
Cc: Andy Lutomirski 
Cc: Hugh Dickins 
Cc: Mel Gorman 
Cc: Nadav Amit 
Cc: Rik van Riel 
Cc: Sergey Senozhatsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: refactor TLB gathering API

2017-08-10T22:54:07+00:00

This patch is a preparatory patch for solving race problems caused by
TLB batch.  For that, we will increase/decrease TLB flush pending count
of mm_struct whenever tlb_[gather|finish]_mmu is called.

Before making it simple, this patch separates architecture specific part
and rename it to arch_tlb_[gather|finish]_mmu and generic part just
calls it.

It shouldn't change any behavior.

Link: http://lkml.kernel.org/r/20170802000818.4760-5-namit@vmware.com
Signed-off-by: Minchan Kim 
Signed-off-by: Nadav Amit 
Acked-by: Mel Gorman 
Cc: Ingo Molnar 
Cc: Russell King 
Cc: Tony Luck 
Cc: Martin Schwidefsky 
Cc: "David S. Miller" 
Cc: Heiko Carstens 
Cc: Yoshinori Sato 
Cc: Jeff Dike 
Cc: Andrea Arcangeli 
Cc: Andy Lutomirski 
Cc: Hugh Dickins 
Cc: Mel Gorman 
Cc: Nadav Amit 
Cc: Rik van Riel 
Cc: Sergey Senozhatsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm

2017-07-27T17:35:07+00:00

Pull ARM fixes from Russell King:
 "Two areas addressed by these fixes:

   - Fixes from Dave Martin for the signal frames that were broken with
     certain configurations. No one noticed until recently.

   - More kexec fixes to ensure that the crashkernel region is correctly
     allocated, and a fix for the location of the device tree when
     several kexec kernels are loaded"

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8687/1: signal: Fix unparseable iwmmxt_sigframe in uc_regspace[]
  ARM: 8686/1: iwmmxt: Add missing __user annotations to sigframe accessors
  ARM: kexec: fix failure to boot crash kernel
  ARM: kexec: avoid allocating crashkernel region outside lowmem

ARM: 8687/1: signal: Fix unparseable iwmmxt_sigframe in uc_regspace[]

2017-07-24T13:26:55+00:00

In kernels with CONFIG_IWMMXT=y running on non-iWMMXt hardware, the
signal frame can be left partially uninitialised in such a way
that userspace cannot parse uc_regspace[] safely.  In particular,
this means that the VFP registers cannot be located reliably in the
signal frame when a multi_v7_defconfig kernel is run on the
majority of platforms.

The cause is that the uc_regspace[] is laid out statically based on
the kernel config, but the decision of whether to save/restore the
iWMMXt registers must be a runtime decision.

To minimise breakage of software that may assume a fixed layout,
this patch emits a dummy block of the same size as iwmmxt_sigframe,
for non-iWMMXt threads.  However, the magic and size of this block
are now filled in to help parsers skip over it.  A new DUMMY_MAGIC
is defined for this purpose.

It is probably legitimate (if non-portable) for userspace to
manufacture its own sigframe for sigreturn, and there is no obvious
reason why userspace should be required to insert a DUMMY_MAGIC
block when running on non-iWMMXt hardware, when omitting it has
worked just fine forever in other configurations.  So in this case,
sigreturn does not require this block to be present.

Reported-by: Edmund Grimley-Evans 
Signed-off-by: Dave Martin 
Signed-off-by: Russell King

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-07-21T17:41:19+00:00

Pull core fixes from Ingo Molnar:
 "A fix to WARN_ON_ONCE() done by modules, plus a MAINTAINERS update"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  debug: Fix WARN_ON_ONCE() for modules
  MAINTAINERS: Update the PTRACE entry

ARM: kexec: fix failure to boot crash kernel

2017-07-20T10:37:42+00:00

When kexec was converted to DTB, the dtb address was passed between
machine_kexec_prepare() and machine_kexec() using a static variable.
This is bad news if you load a crash kernel followed by a normal
kernel or vice versa - the last loaded kernel overwrites the dtb
address.

This can result in kexec failures, as (eg) we try to boot the crash
kernel with the last loaded dtb.  For example, with:

the crash kernel fails to find the dtb.

Avoid this by defining a kimage architecture structure, and store
the address to be passed in r2 there, which will either be the ATAGs
or the dtb blob.

Fixes: 4cabd1d9625c ("ARM: 7539/1: kexec: scan for dtb magic in segments")
Fixes: 42d720d1731a ("ARM: kexec: Make .text R/W in machine_kexec")
Reported-by: Keerthy 
Tested-by: Keerthy 
Signed-off-by: Russell King

debug: Fix WARN_ON_ONCE() for modules

2017-07-20T10:31:04+00:00

Mike Galbraith reported a situation where a WARN_ON_ONCE() call in DRM
code turned into an oops.  As it turns out, WARN_ON_ONCE() seems to be
completely broken when called from a module.

The bug was introduced with the following commit:

  19d436268dde ("debug: Add _ONCE() logic to report_bug()")

That commit changed WARN_ON_ONCE() to move its 'once' logic into the bug
trap handler.  It requires a writable bug table so that the BUGFLAG_DONE
bit can be written to the flags to indicate the first warning has
occurred.

The bug table was made writable for vmlinux, which relies on
vmlinux.lds.S and vmlinux.lds.h for laying out the sections.  However,
it wasn't made writable for modules, which rely on the ELF section
header flags.

Reported-by: Mike Galbraith 
Tested-by: Masami Hiramatsu 
Signed-off-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 19d436268dde ("debug: Add _ONCE() logic to report_bug()")
Link: http://lkml.kernel.org/r/a53b04235a65478dd9afc51f5b329fdc65c84364.1500095401.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

Merge tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2017-07-19T15:55:18+00:00

Pull structure randomization updates from Kees Cook:
 "Now that IPC and other changes have landed, enable manual markings for
  randstruct plugin, including the task_struct.

  This is the rest of what was staged in -next for the gcc-plugins, and
  comes in three patches, largest first:

   - mark "easy" structs with __randomize_layout

   - mark task_struct with an optional anonymous struct to isolate the
     __randomize_layout section

   - mark structs to opt _out_ of automated marking (which will come
     later)

  And, FWIW, this continues to pass allmodconfig (normal and patched to
  enable gcc-plugins) builds of x86_64, i386, arm64, arm, powerpc, and
  s390 for me"

* tag 'gcc-plugins-v4.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  randstruct: opt-out externally exposed function pointer structs
  task_struct: Allow randomized layout
  randstruct: Mark various structs for randomization

Merge branch 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-07-15T18:17:52+00:00

Pull uacess-unaligned removal from Al Viro:
 "That stuff had just one user, and an exotic one, at that - binfmt_flat
  on arm and m68k"

* 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kill {__,}{get,put}_user_unaligned()
  binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail