With the new ASID allocation algorithm, active ASIDs at the time of a
rollover event will be marked as reserved, so active mm_structs can
continue to operate with the same ASID as before. This in turn means
that we don't need to worry about allocating a new ASID to an mm that
is currently active (installed in TTBR0).

Since updating the pgd and ASID is atomic on LPAE systems (by virtue of
the two being fields in the same hardware register), we can dispose of
the reserved TTBR0 and rely on whatever tables we currently have live.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The IDE code used to specify the IDE IRQs for chipsets operating in
legacy mode.  This appears to no longer work, and this information must
be provided by the arch.  Do so.  This partially fixes CY82C693 (and
probably others) on Footbridge platforms.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Cleanup the LEDs code to use ioremap()/writeb() to access the register.
This allows us to move the definitions out of a header file directly
into the ebsa285 support code.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Make pgd allocation retry on failure; we really need this to succeed
otherwise fork() can trigger OOMs.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add a one-shot mode for the DC21285 timer.  This allows us to use the
NO_HZ modes on this platform.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This adds support for the Marvell Tauros3 cache controller which
is compatible with pl310 cache controller but broadcasts L1 cache
operations to L2 cache. While updating the binding documentation,
clean up the list of possible compatibles. Also reorder driver
compatibles to allow non-ARM derivated to be compatible to ARM
cache controller compatibles.
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Enable the compiler intrinsic for byte swapping on arch ARM. This
allows the compiler to detect and be able to optimize out byte
swappings, and has a very modest benefit on vmlinux size (Linaro gcc
4.8):

text data bss dec hex filename
2840310 123932 61960 3026202 2e2d1a vmlinux-lart #orig
2840152 123932 61960 3026044 2e2c7c vmlinux-lart #builtin-bswap

6473120 314840 5616016 12403976 bd4508 vmlinux-mxs #orig
6472586 314848 5616016 12403450 bd42fa vmlinux-mxs #builtin-bswap

7419872 318372 379556 8117800 7bde28 vmlinux-imx_v6_v7 #orig
7419170 318364 379556 8117090 7bdb62 vmlinux-imx_v6_v7 #builtin-bswap
Signed-off-by: NKim Phillips <kim.phillips@freescale.com>
Reviewed-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

sync_cache_w already includes a dsb, so we can just use sev() directly
then following a cache-sync.
Acked-by: NDave Martin <Dave.Martin@arm.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

These symbols are only referenced in this source file so can be made
static, and the efficiency table is constant data so can be declared as
such.  This avoids polluting the global namespace and fixes warnings
from sparse.

The function arch_scale_freq_power() is still not prototyped or static,
this is a separate issue as this is overriding a weak symbol from the
scheduler which neglects to provide a prototype.
Signed-off-by: NMark Brown <broonie@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There is a miscompilation of csum_tcpudp_magic() due to the way we pass
the asm() operands in.  Fortunately, this doesn't affect the IP code,
but can affect anyone who passes ntohs(udp->len) as the length argument,
or protocols with more than 8 bits.

The problem stems from passing 16-bit operands into an asm() - GCC makes
no guarantees about what may be in the high 16-bits of such a register
passed into assembly which is in the "HI" machine mode.

Address this by changing the way we handle the 16-bit arguments - since
accumulating the protocol and length can never overflow, we can delegate
this to the compiler to perform, and then accumulate it into the
checksum inside the asm(), taking account of the endian-ness via an
appropriate 32-bit rotation.

While we are here, also realise that there's a chance to optimise this
a little: several callers from IP code pass a constant zero as the
initial sum.  This is wasteful - if we detect this condition, we can
optimise away one instruction.
Tested-by: NMaxime Bizon <mbizon@freebox.fr>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Set-associative caches on all v7 implementations map the index bits
to physical addresses LSBs and tag bits to MSBs. As the last level
of cache on current and upcoming ARM systems grows in size,
this means that under normal DRAM controller configurations, the
current v7 cache flush routine using set/way operations triggers a
DRAM memory controller precharge/activate for every cache line
writeback since the cache routine cleans lines by first fixing the
index and then looping through ways (index bits are mapped to lower
physical addresses on all v7 cache implementations; this means that,
with last level cache sizes in the order of MBytes, lines belonging
to the same set but different ways map to different DRAM pages).

Given the random content of cache tags, swapping the order between
indexes and ways loops do not prevent DRAM pages precharge and
activate cycles but at least, on average, improves the chances that
either multiple lines hit the same page or multiple lines belong to
different DRAM banks, improving throughput significantly.

This patch swaps the inner loops in the v7 cache flushing routine
to carry out the clean operations first on all sets belonging to
a given way (looping through sets) and then decrementing the way.

Benchmarks showed that by swapping the ordering in which sets and
ways are decremented in the v7 cache flushing routine, that uses
set/way operations, time required to flush caches is reduced
significantly, owing to improved writebacks throughput to the DRAM
controller.

Benchmarks results vary and depend heavily on the last level of
cache tag RAM content when cache is cleaned and invalidated, ranging
from 2x throughput when all tag RAM entries contain dirty lines
mapping to sequential pages of RAM to 1x (ie no improvement) when
all tag RAM accesses trigger a DRAM precharge/activate cycle, as the
current code implies on most DRAM controller configurations.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We have a handy macro to replace open coded __cpuc_flush_dcache_area(()
and outer_clean_range() sequences. Let's use it. No functional change.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Clean up the setup ARM printks a bit. Add printk level to a few
that were missing (CPU: <...> ones, in particular), and switch from
printk(KERN_* ..) to pr_*().

Finally, un-wrap some long lines since it makes it harder to grep the
sources from where an error came from and tweak some cases of indentation.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Driver core clears the driver data to NULL after device_release
or on probe failure, so just remove it from here.

Driver core change:
"device-core: Ensure drvdata = NULL when no driver is bound"
(sha1: 0998d063)
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Driver core clears the driver data to NULL after device_release
or on probe failure, so just remove it from here.

Driver core change:
"device-core: Ensure drvdata = NULL when no driver is bound"
(sha1: 0998d063)
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Driver core clears the driver data to NULL after device_release
or on probe failure, so just remove it from here.

Driver core change:
"device-core: Ensure drvdata = NULL when no driver is bound"
(sha1: 0998d063)
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The only v7-M platform only has some unused stubs in its
mach/entry-macro.S file. So don't include it which allows efm32 to drop
the file.
Acked-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We don't need the offset for the first function name in each backtrace
entry; this needlessly consumes screen space.  This is virtually always
the first or second instruction in the called function.

Also, recognise stmfd instructions which include r10 as a valid stack
saving instruction, and when dumping the registers, dump six registers
per line rather than five, and fix the wrapping.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ioremap_cache is more aligned with other architectures. There are only
2 users of this in the kernel: pxa2xx-flash and Xen.

This fixes Xen build failures on arm64 caused by commit c04e8e2f (arm64:
allow ioremap_cache() to use existing RAM mappings)

drivers/tty/hvc/hvc_xen.c:233:2: error: implicit declaration of function 'ioremap_cached' [-Werror=implicit-function-declaration]
drivers/xen/grant-table.c:1174:3: error: implicit declaration of function 'ioremap_cached' [-Werror=implicit-function-declaration]
drivers/xen/xenbus/xenbus_probe.c:778:4: error: implicit declaration of function 'ioremap_cached' [-Werror=implicit-function-declaration]
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Pull ARM SoC fixes from Olof Johansson:
 "Much smaller batch of fixes this week.

  Biggest one is a revert of an OMAP display change that removed some
  non-DT pinmux code that was still needed for 3.13 to get DSI displays
  to work.

  There's also a fix that resolves some misdescribed GPIO controller
  resources on shmobile.  The rest are mostly smaller fixes, a couple of
  MAINTAINERS updates, etc"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  Revert "ARM: OMAP2+: Remove legacy mux code for display.c"
  MAINTAINERS: Add keystone clock drivers
  MAINTAINERS: Add keystone git tree information
  ARM: s3c64xx: dt: Fix boot failure due to double clock initialization
  ARM: shmobile: r8a7790: Fix GPIO resources in DTS
  irqchip: renesas-intc-irqpin: Fix register bitfield shift calculation
  ARM: shmobile: lager: phy fixup needs CONFIG_PHYLIB

Pull firewire fixlet from Stefan Richter:
 "A one-liner to reenable WRITE SAME over SBP-2 like in v3.8...v3.12.
  Buggy targets which could malfunction when being subjected to this
  command are already sufficiently protected by a scsi_level check in sd
  + SCSI core"

* tag 'firewire-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: sbp2: bring back WRITE SAME support

Pull SCSI target fixes from Nicholas Bellinger:
 "Mostly minor items this time around, the most notable being a FILEIO
  backend change to enforce hw_max_sectors based upon the current
  block_size to address a bug where large sized I/Os (> 1M) where being
  rejected"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  qla2xxx: Fix scsi_host leak on qlt_lport_register callback failure
  target: Remove extra percpu_ref_init
  target/file: Update hw_max_sectors based on current block_size
  iser-target: Move INIT_WORK setup into isert_create_device_ib_res
  iscsi-target: Fix incorrect np->np_thread NULL assignment
  qla2xxx: Fix schedule_delayed_work() for target timeout calculations
  iser-target: fix error return code in isert_create_device_ib_res()
  iscsi-target: Fix-up all zero data-length CDBs with R/W_BIT set
  target: Remove write-only stats fields and lock from struct se_node_acl
  iscsi-target: return -EINVAL on oversized configfs parameter

Pull AIO leak fixes from Ben LaHaise:
 "I've put these two patches plus Linus's change through a round of
  tests, and it passes millions of iterations of the aio numa
  migratepage test, as well as a number of repetitions of a few simple
  read and write tests.

  The first patch fixes the memory leak Kent introduced, while the
  second patch makes aio_migratepage() much more paranoid and robust"

* git://git.kvack.org/~bcrl/aio-next:
  aio/migratepages: make aio migrate pages sane
  aio: fix kioctx leak introduced by "aio: Fix a trinity splat"

Since commit 36bc08cc ("fs/aio: Add support to aio ring pages
migration") the aio ring setup code has used a special per-ring backing
inode for the page allocations, rather than just using random anonymous
pages.

However, rather than remembering the pages as it allocated them, it
would allocate the pages, insert them into the file mapping (dirty, so
that they couldn't be free'd), and then forget about them.  And then to
look them up again, it would mmap the mapping, and then use
"get_user_pages()" to get back an array of the pages we just created.

Now, not only is that incredibly inefficient, it also leaked all the
pages if the mmap failed (which could happen due to excessive number of
mappings, for example).

So clean it all up, making it much more straightforward.  Also remove
some left-overs of the previous (broken) mm_populate() usage that was
removed in commit d6c355c7 ("aio: fix race in ring buffer page
lookup introduced by page migration support") but left the pointless and
now misleading MAP_POPULATE flag around.
Tested-and-acked-by: NBenjamin LaHaise <bcrl@kvack.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The arbitrary restriction on page counts offered by the core
migrate_page_move_mapping() code results in rather suspicious looking
fiddling with page reference counts in the aio_migratepage() operation.
To fix this, make migrate_page_move_mapping() take an extra_count parameter
that allows aio to tell the code about its own reference count on the page
being migrated.

While cleaning up aio_migratepage(), make it validate that the old page
being passed in is actually what aio_migratepage() expects to prevent
misbehaviour in the case of races.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>

e34ecee2 reworked the percpu reference
counting to correct a bug trinity found.  Unfortunately, the change lead
to kioctxes being leaked because there was no final reference count to
put.  Add that reference count back in to fix things.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Cc: stable@vger.kernel.org

Commit 1bf49dd4 ("./Makefile: export initial ramdisk compression
config option") started setting the INITRD_COMPRESS environment variable
depending on which decompression models the kernel had available.

That is completely broken.

For example, we by default have CONFIG_RD_LZ4 enabled, and are able to
decompress such an initrd, but the user tools to *create* such an initrd
may not be availble.  So trying to tell dracut to generate an
lz4-compressed image just because we can decode such an image is
completely inappropriate.

Cc: J P <ppandit@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Beulich <JBeulich@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull xfs bugfixes from Ben Myers:
 "This contains fixes for some asserts
   related to project quotas, a memory leak, a hang when disabling group or
   project quotas before disabling user quotas, Dave's email address, several
   fixes for the alignment of file allocation to stripe unit/width geometry, a
   fix for an assertion with xfs_zero_remaining_bytes, and the behavior of
   metadata writeback in the face of IO errors.

   Details:
   - fix memory leak in xfs_dir2_node_removename
   - fix quota assertion in xfs_setattr_size
   - fix quota assertions in xfs_qm_vop_create_dqattach
   - fix for hang when disabling group and project quotas before
     disabling user quotas
   - fix Dave Chinner's email address in MAINTAINERS
   - fix for file allocation alignment
   - fix for assertion in xfs_buf_stale by removing xfsbdstrat
   - fix for alignment with swalloc mount option
   - fix for "retry forever" semantics on IO errors"

* tag 'xfs-for-linus-v3.13-rc5' of git://oss.sgi.com/xfs/xfs:
  xfs: abort metadata writeback on permanent errors
  xfs: swalloc doesn't align allocations properly
  xfs: remove xfsbdstrat error
  xfs: align initial file allocations correctly
  MAINTAINERS: fix incorrect mail address of XFS maintainer
  xfs: fix infinite loop by detaching the group/project hints from user dquot
  xfs: fix assertion failure at xfs_setattr_nonsize
  xfs: fix false assertion at xfs_qm_vop_create_dqattach
  xfs: fix memory leak in xfs_dir2_node_removename

Commit 597d795a ('mm: do not allocate page->ptl dynamically, if
spinlock_t fits to long') restructures some allocators that are compiled
even if USE_SPLIT_PTLOCKS arn't used.  It results in compilation
failure:

  mm/memory.c:4282:6: error: 'struct page' has no member named 'ptl'
  mm/memory.c:4288:12: error: 'struct page' has no member named 'ptl'

Add in the missing ifdef.

Fixes: 597d795a ('mm: do not allocate page->ptl dynamically, if spinlock_t fits to long')
Signed-off-by: NOlof Johansson <olof@lixom.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull ARC fix from Vineet Gupta:
 "Fix busted syscall table due to unistd header inclusion issue"

* tag 'arc-fixes-for-3.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: Allow conditional multiple inclusion of uapi/asm/unistd.h

Pull arm64 ptrace fix from Catalin Marinas.

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: ptrace: avoid using HW_BREAKPOINT_EMPTY for disabled events

Some pstore backing devices use on board flash as persistent
storage. These have limited numbers of write cycles so it
is a poor idea to use them from high frequency operations.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Merge tag 'dmaengine-fixes-3.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine

Pull dmaengine fixes from Dan Williams:

 - deprecation of net_dma to be removed in 3.14

 - crash regression fix in pl330 from the dmaengine_unmap rework

 - crash regression fix for any channel running raid ops without
   CONFIG_ASYNC_TX_DMA from dmaengine_unmap

 - memory leak regression in mv_xor from dmaengine_unmap

 - build warning regressions in mv_xor, fsldma, ppc4xx, txx9, and
   at_hdmac from dmaengine_unmap

 - sleep in atomic regression in dma_async_memcpy_pg_to_pg

 - new fix in mv_xor for handling channel initialization failures

* tag 'dmaengine-fixes-3.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine:
  net_dma: mark broken
  dma: pl330: ensure DMA descriptors are zero-initialised
  dmaengine: fix sleep in atomic
  dmaengine: mv_xor: fix oops when channels fail to initialise
  dma: mv_xor: Use dmaengine_unmap_data for the self-tests
  dmaengine: fix enable for high order unmap pools
  dma: fix build warnings in txx9
  dmatest: fix build warning on mips
  dma: fix fsldma build warnings
  dma: fix build warnings in ppc4xx
  dmaengine: at_hdmac: remove unused function
  dma: mv_xor: remove mv_desc_get_dest_addr()

Pull KVM fixes from Paolo Bonzini:
 "The PPC folks had a large amount of changes queued for 3.13, and now
  they are fixing the bugs"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PPC: Book3S HV: Don't drop low-order page address bits
  powerpc: book3s: kvm: Don't abuse host r2 in exit path
  powerpc/kvm/booke: Fix build break due to stack frame size warning
  KVM: PPC: Book3S: PR: Enable interrupts earlier
  KVM: PPC: Book3S: PR: Make svcpu -> vcpu store preempt savvy
  KVM: PPC: Book3S: PR: Export kvmppc_copy_to|from_svcpu
  KVM: PPC: Book3S: PR: Don't clobber our exit handler id
  powerpc: kvm: fix rare but potential deadlock scene
  KVM: PPC: Book3S HV: Take SRCU read lock around kvm_read_guest() call
  KVM: PPC: Book3S HV: Make tbacct_lock irq-safe
  KVM: PPC: Book3S HV: Refine barriers in guest entry/exit
  KVM: PPC: Book3S HV: Fix physical address calculations

In struct page we have enough space to fit long-size page->ptl there,
but we use dynamically-allocated page->ptl if size(spinlock_t) is larger
than sizeof(int).

It hurts 64-bit architectures with CONFIG_GENERIC_LOCKBREAK, where
sizeof(spinlock_t) == 8, but it easily fits into struct page.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 81c0a2bb ("mm: page_alloc: fair zone allocator policy") meant
to bring aging fairness among zones in system, but it was overzealous
and badly regressed basic workloads on NUMA systems.

Due to the way kswapd and page allocator interacts, we still want to
make sure that all zones in any given node are used equally for all
allocations to maximize memory utilization and prevent thrashing on the
highest zone in the node.

While the same principle applies to NUMA nodes - memory utilization is
obviously improved by spreading allocations throughout all nodes -
remote references can be costly and so many workloads prefer locality
over memory utilization.  The original change assumed that
zone_reclaim_mode would be a good enough predictor for that, but it
turned out to be as indicative as a coin flip.

Revert the NUMA aspect of the fairness until we can find a proper way to
make it configurable and agree on a sane default.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NMichal Hocko <mhocko@suse.cz>
Signed-off-by: NMel Gorman <mgorman@suse.de>
Cc: <stable@kernel.org> # 3.12
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit 73f038b8.  The NUMA behaviour of this patch is
less than ideal.  An alternative approch is to interleave allocations
only within local zones which is implemented in the next patch.

Cc: stable@vger.kernel.org
Signed-off-by: NMel Gorman <mgorman@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Sasha Levin found a NULL pointer dereference that is due to a missing
page table lock, which in turn is due to the pmd entry in question being
a transparent huge-table entry.

The code - introduced in commit 1998cc04 ("mm: make
madvise(MADV_WILLNEED) support swap file prefetch") - correctly checks
for this situation using pmd_none_or_trans_huge_or_clear_bad(), but it
turns out that that function doesn't work correctly.

pmd_none_or_trans_huge_or_clear_bad() expected that pmd_bad() would
trigger if the transparent hugepage bit was set, but it doesn't do that
if pmd_numa() is also set. Note that the NUMA bit only gets set on real
NUMA machines, so people trying to reproduce this on most normal
development systems would never actually trigger this.

Fix it by removing the very subtle (and subtly incorrect) expectation,
and instead just checking pmd_trans_huge() explicitly.
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Acked-by: NAndrea Arcangeli <aarcange@redhat.com>
[ Additionally remove the now stale test for pmd_trans_huge() inside the
  pmd_bad() case - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>