Michel while working on the working set estimation code, noticed that
calling get_page_unless_zero() on a random pfn_to_page(random_pfn)
wasn't safe, if the pfn ended up being a tail page of a transparent
hugepage under splitting by __split_huge_page_refcount().

He then found the problem could also theoretically materialize with
page_cache_get_speculative() during the speculative radix tree lookups
that uses get_page_unless_zero() in SMP if the radix tree page is freed
and reallocated and get_user_pages is called on it before
page_cache_get_speculative has a chance to call get_page_unless_zero().

So the best way to fix the problem is to keep page_tail->_count zero at
all times.  This will guarantee that get_page_unless_zero() can never
succeed on any tail page.  page_tail->_mapcount is guaranteed zero and
is unused for all tail pages of a compound page, so we can simply
account the tail page references there and transfer them to
tail_page->_count in __split_huge_page_refcount() (in addition to the
head_page->_mapcount).

While debugging this s/_count/_mapcount/ change I also noticed get_page is
called by direct-io.c on pages returned by get_user_pages.  That wasn't
entirely safe because the two atomic_inc in get_page weren't atomic.  As
opposed to other get_user_page users like secondary-MMU page fault to
establish the shadow pagetables would never call any superflous get_page
after get_user_page returns.  It's safer to make get_page universally safe
for tail pages and to use get_page_foll() within follow_page (inside
get_user_pages()).  get_page_foll() is safe to do the refcounting for tail
pages without taking any locks because it is run within PT lock protected
critical sections (PT lock for pte and page_table_lock for
pmd_trans_huge).

The standard get_page() as invoked by direct-io instead will now take
the compound_lock but still only for tail pages.  The direct-io paths
are usually I/O bound and the compound_lock is per THP so very
finegrined, so there's no risk of scalability issues with it.  A simple
direct-io benchmarks with all lockdep prove locking and spinlock
debugging infrastructure enabled shows identical performance and no
overhead.  So it's worth it.  Ideally direct-io should stop calling
get_page() on pages returned by get_user_pages().  The spinlock in
get_page() is already optimized away for no-THP builds but doing
get_page() on tail pages returned by GUP is generally a rare operation
and usually only run in I/O paths.

This new refcounting on page_tail->_mapcount in addition to avoiding new
RCU critical sections will also allow the working set estimation code to
work without any further complexity associated to the tail page
refcounting with THP.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'next/soc' of git://git.linaro.org/people/arnd/arm-soc: (21 commits)
  MAINTAINERS: add ARM/FREESCALE IMX6 entry
  arm/imx: merge i.MX3 and i.MX6
  arm/imx6q: add suspend/resume support
  arm/imx6q: add device tree machine support
  arm/imx6q: add smp and cpu hotplug support
  arm/imx6q: add core drivers clock, gpc, mmdc and src
  arm/imx: add gic_handle_irq function
  arm/imx6q: add core definitions and low-level debug uart
  arm/imx6q: add device tree source
  ARM: highbank: add suspend support
  ARM: highbank: Add cpu hotplug support
  ARM: highbank: add SMP support
  MAINTAINERS: add Calxeda Highbank ARM platform
  ARM: add Highbank core platform support
  ARM: highbank: add devicetree source
  ARM: l2x0: add empty l2x0_of_init
  picoxcell: add a definition of VMALLOC_END
  picoxcell: remove custom ioremap implementation
  picoxcell: add the DTS for the PC7302 board
  picoxcell: add the DTS for pc3x2 and pc3x3 devices
  ...

Fix up trivial conflicts in arch/arm/Kconfig, and some more header file
conflicts in arch/arm/mach-omap2/board-generic.c (as per an ealier merge
by Arnd).

* 'next/dt' of git://git.linaro.org/people/arnd/arm-soc:
  ARM: gic: use module.h instead of export.h
  ARM: gic: fix irq_alloc_descs handling for sparse irq
  ARM: gic: add OF based initialization
  ARM: gic: add irq_domain support
  irq: support domains with non-zero hwirq base
  of/irq: introduce of_irq_init
  ARM: at91: add at91sam9g20 and Calao USB A9G20 DT support
  ARM: at91: dt: at91sam9g45 family and board device tree files
  arm/mx5: add device tree support for imx51 babbage
  arm/mx5: add device tree support for imx53 boards
  ARM: msm: Add devicetree support for msm8660-surf
  msm_serial: Add devicetree support
  msm_serial: Use relative resources for iomem

Fix up conflicts in arch/arm/mach-at91/{at91sam9260.c,at91sam9g45.c}

* 'next/cleanup2' of git://git.linaro.org/people/arnd/arm-soc: (31 commits)
  ARM: OMAP: Warn if omap_ioremap is called before SoC detection
  ARM: OMAP: Move set_globals initialization to happen in init_early
  ARM: OMAP: Map SRAM later on with ioremap_exec()
  ARM: OMAP: Remove calls to SRAM allocations for framebuffer
  ARM: OMAP: Avoid cpu_is_omapxxxx usage until map_io is done
  ARM: OMAP1: Use generic map_io, init_early and init_irq
  arm/dts: OMAP3+: Add mpu, dsp and iva nodes
  arm/dts: OMAP4: Add a main ocp entry bound to l3-noc driver
  ARM: OMAP2+: l3-noc: Add support for device-tree
  ARM: OMAP2+: board-generic: Add i2c static init
  ARM: OMAP2+: board-generic: Add DT support to generic board
  arm/dts: Add support for OMAP3 Beagle board
  arm/dts: Add initial device tree support for OMAP3 SoC
  arm/dts: Add support for OMAP4 SDP board
  arm/dts: Add support for OMAP4 PandaBoard
  arm/dts: Add initial device tree support for OMAP4 SoC
  ARM: OMAP: omap_device: Add a method to build an omap_device from a DT node
  ARM: OMAP: omap_device: Add omap_device_[alloc|delete] for DT integration
  of: Add helpers to get one string in multiple strings property
  ARM: OMAP2+: devices: Remove all omap_device_pm_latency structures
  ...

Fix up trivial header file conflicts in arch/arm/mach-omap2/board-generic.c

* 'next/cross-platform' of git://git.linaro.org/people/arnd/arm-soc:
  arm/imx: use Kconfig choice for low-level debug UART selection
  ARM: realview: use Kconfig choice for debug UART selection
  ARM: plat-samsung: use Kconfig choice for debug UART selection
  ARM: versatile: convert logical CPU numbers to physical numbers
  ARM: ux500: convert logical CPU numbers to physical numbers
  ARM: shmobile: convert logical CPU numbers to physical numbers
  ARM: msm: convert logical CPU numbers to physical numbers
  ARM: exynos4: convert logical CPU numbers to physical numbers

Fix up trivial conflict (config DEBUG_S3C_UART move/split vs addition of
ARM_KPROBES_TEST option) in arch/arm/Kconfig.debug

* 'next/devel' of git://git.linaro.org/people/arnd/arm-soc: (50 commits)
  ARM: tegra: update defconfig
  arm/tegra: Harmony: Configure PMC for low-level interrupts
  arm/tegra: device tree support for ventana board
  arm/tegra: add support for ventana pinmuxing
  arm/tegra: prepare Seaboard pinmux code for derived boards
  arm/tegra: pinmux: ioremap registers
  gpio/tegra: Convert to a platform device
  arm/tegra: Convert pinmux driver to a platform device
  arm/dt: Tegra: Add pinmux node to tegra20.dtsi
  arm/tegra: Prep boards for gpio/pinmux conversion to pdevs
  ARM: mx5: fix clock usage for suspend
  ARM i.MX entry-macro.S: remove now unused code
  ARM i.MX boards: use CONFIG_MULTI_IRQ_HANDLER
  ARM i.MX tzic: add handle_irq function
  ARM i.MX avic: add handle_irq function
  ARM: mx25: Add the missing IIM base definition
  ARM i.MX avic: convert to use generic irq chip
  mx31moboard: Add poweroff support
  ARM: mach-qong: Add watchdog support
  ARM: davinci: AM18x: Add wl1271/wlan support
  ...

Fix up conflicts in:
	arch/arm/mach-at91/at91sam9g45.c
	arch/arm/mach-mx5/devices-imx53.h
	arch/arm/plat-mxc/include/mach/memory.h

* 'next/board' of git://git.linaro.org/people/arnd/arm-soc: (34 commits)
  ep93xx: add support Vision EP9307 SoM
  ARM: mxs: Add initial support for DENX MX28
  ARM: EXYNOS4: Add support SMDK4412 Board
  ARM: EXYNOS4: Add MCT support for EXYNOS4412
  ARM: EXYNOS4: Add functions for gic interrupt handling
  ARM: EXYNOS4: Add support clock for EXYNOS4412
  ARM: EXYNOS4: Add support new EXYNOS4412 SoC
  ARM: EXYNOS4: Add support MCT PPI for EXYNOS4212
  ARM: EXYNOS4: Add support PPI in external GIC
  ARM: EXYNOS4: convert boot_params to atag_offset
  ixp4xx: support omicron ixp425 based boards
  ARM: EXYNOS4: Add support SMDK4212 Board
  ARM: EXYNOS4: Add support PM for EXYNOS4212
  ARM: EXYNOS4: Add support clock for EXYNOS4212
  ARM: EXYNOS4: Add support new EXYNOS4212 SoC
  at91: USB-A9G20 C01 & C11 board support
  at91: merge board USB-A9260 and USB-A9263 together
  at91: add support for RSIs EWS board
  ARM: SAMSUNG: Fix mask value for S5P64X0 CPU IDs
  ARM: SAMSUNG: Fix mask for S3C64xx CPU IDs
  ...

* 'next/deletion' of git://git.linaro.org/people/arnd/arm-soc:
  ARM: mach-nuc93x: delete

Fix up trivial delete/edit conflicts in
	arch/arm/mach-nuc93x/{Makefile.boot,mach-nuc932evb.c,time.c}

* 'next/pm' of git://git.linaro.org/people/arnd/arm-soc: (66 commits)
  ARM: CSR: PM: use outer_resume to resume L2 cache
  ARM: CSR: call l2x0_of_init to init L2 cache of SiRFprimaII
  ARM: OMAP: voltage: voltage layer present, even when CONFIG_PM=n
  ARM: CSR: PM: add sleep entry for SiRFprimaII
  ARM: CSR: PM: save/restore irq status in suspend cycle
  ARM: CSR: PM: save/restore timer status in suspend cycle
  OMAP4: PM: TWL6030: add cmd register
  OMAP4: PM: TWL6030: fix ON/RET/OFF voltages
  OMAP4: PM: TWL6030: address 0V conversions
  OMAP4: PM: TWL6030: fix uv to voltage for >0x39
  OMAP4: PM: TWL6030: fix voltage conversion formula
  omap: voltage: add a stub header file for external/regulator use
  OMAP2+: VC: more registers are per-channel starting with OMAP5
  OMAP3+: voltage: update nominal voltage in voltdm_scale() not VC post-scale
  OMAP3+: voltage: rename omap_voltage_get_nom_volt -> voltdm_get_voltage
  OMAP3+: voltdm: final removal of omap_vdd_info
  OMAP3+: voltage: move/rename curr_volt from vdd_info into struct voltagedomain
  OMAP3+: voltage: rename scale and reset functions using voltdm_ prefix
  OMAP3+: VP: combine setting init voltage into common function
  OMAP3+: VP: remove unused omap_vp_get_curr_volt()
  ...

Fix up trivial conflict in arch/arm/mach-prima2/l2x0.c (code removal vs
edit)

* 'next/timer' of git://git.linaro.org/people/arnd/arm-soc:
  clocksource: fixup ux500 build problems
  ARM: omap: use __devexit_p in dmtimer driver
  ARM: ux500: Reprogram timers upon resume
  ARM: plat-nomadik: timer: Export reset functions
  ARM: plat-nomadik: timer: Add support for periodic timers
  ARM: ux500: Move timer code to separate file
  ARM: ux500: add support for clocksource DBX500 PRCMU
  clocksource: add DBX500 PRCMU Timer support
  ARM: plat-nomadik: MTU sched_clock as an option
  ARM: OMAP: dmtimer: add error handling to export APIs
  ARM: OMAP: dmtimer: low-power mode support
  ARM: OMAP: dmtimer: skip reserved timers
  ARM: OMAP: dmtimer: pm_runtime support
  ARM: OMAP: dmtimer: switch-over to platform device driver
  ARM: OMAP: dmtimer: platform driver
  ARM: OMAP2+: dmtimer: convert to platform devices
  ARM: OMAP1: dmtimer: conversion to platform devices
  ARM: OMAP2+: dmtimer: add device names to flck nodes
  ARM: OMAP: Add support for dmtimer v2 ip

* 'next/driver' of git://git.linaro.org/people/arnd/arm-soc:
  hw_random: add driver for atmel true hardware random number generator
  ARM: at91: at91sam9g45: add trng clock and platform device
  MX53 Enable the AHCI SATA on MX53 SMD board
  MX53 Enable the AHCI SATA on MX53 LOCO board
  MX53 Enable the AHCI SATA on MX53 ARD board
  AHCI Add the AHCI SATA feature on the MX53 platforms
  Fix pata imx resource
  ARM: imx: Define functions for registering PATA
  ARM: imx: Add PATA clock support
  ARM: imx: Add PATA resources for other i.MX processors
  imx: efika: Enable pata.
  imx51: add pata clock
  imx51: add pata device

Fix up trivial conflict (new selects next to each other from separate
branches for EFIKA_COMMON) in arch/arm/mach-mx5/Kconfig

* 'next/cleanup' of git://git.linaro.org/people/arnd/arm-soc: (125 commits)
  ARM: mach-mxs: fix machines' initializers order
  mmc: mxcmmc: explicitly includes mach/hardware.h
  arm/imx: explicitly includes mach/hardware.h in pm-imx27.c
  arm/imx: remove mx27_setup_weimcs() from mx27.h
  arm/imx: explicitly includes mach/hardware.h in mach-kzm_arm11_01.c
  arm/imx: remove mx31_setup_weimcs() from mx31.h
  ARM: tegra: devices.c should include devices.h
  ARM: tegra: cpu-tegra: unexport two functions
  ARM: tegra: cpu-tegra: sparse type fix
  ARM: tegra: dma: staticify some tables and functions
  ARM: tegra: tegra2_clocks: don't export some tables
  ARM: tegra: tegra_powergate_is_powered should be static
  ARM: tegra: tegra_rtc_read_ms should be static
  ARM: tegra: tegra_init_cache should be static
  ARM: tegra: pcie: 0 -> NULL changes
  ARM: tegra: pcie: include board.h
  ARM: tegra: pcie: don't cast __iomem pointers
  ARM: tegra: tegra2_clocks: 0 -> NULL changes
  ARM: tegra: tegra2_clocks: don't cast __iomem pointers
  ARM: tegra: timer: don't cast __iomem pointers
  ...

Fix up trivial conflicts in
  arch/arm/mach-omap2/Makefile,
  arch/arm/mach-u300/{Makefile.boot,core.c}
  arch/arm/plat-{mxc,omap}/devices.c

* 'next/fixes' of git://git.linaro.org/people/arnd/arm-soc: (28 commits)
  ARM: pxa/cm-x300: properly set bt_reset pin
  ARM: mmp: rename SHEEVAD to GPLUGD
  ARM: imx: Fix typo 'MACH_MX31_3DS_MXC_NAND_USE_BBT'
  ARM: i.MX28: shift frac value in _CLK_SET_RATE
  plat-mxc: iomux-v3.h: implicitly enable pull-up/down when that's desired
  ARM: mx5: fix clock usage for suspend
  ARM: pxa: use correct __iomem annotations
  ARM: pxa: sharpsl pm needs SPI
  ARM: pxa: centro and treo680 need palm27x
  ARM: pxa: make pxafb_smart_*() empty when not enabled
  ARM: pxa: select POWER_SUPPLY on raumfeld
  ARM: pxa: pxa95x is incompatible with earlier pxa
  ARM: pxa: CPU_FREQ_TABLE is needed for CPU_FREQ
  ARM: pxa: pxa95x/saarb depends on pxa3xx code
  ARM: pxa: allow selecting just one of TREO680/CENTRO
  ARM: pxa: export symbols from pxa3xx-ulpi
  ARM: pxa: make zylonite_pxa*_init declaration match code
  ARM: pxa/z2: fix building error of pxa27x_cpu_suspend() no longer available
  ARM: at91: add defconfig for at91sam9g45 family
  ARM: at91: remove dependency for Atmel PWM driver selector in Kconfig
  ...

Conflicts:
	Documentation/devicetree/bindings/arm/fsl.txt
	arch/arm/Kconfig
	arch/arm/Kconfig.debug
	arch/arm/plat-mxc/include/mach/common.h

Conflicts:
	arch/arm/mach-mxs/include/mach/gpio.h
	arch/arm/mach-omap2/board-generic.c
	arch/arm/plat-mxc/include/mach/gpio.h

* 'for-linus/i2c-3.2' of git://git.fluff.org/bjdooks/linux: (47 commits)
  i2c-s3c2410: Add device tree support
  i2c-s3c2410: Keep a copy of platform data and use it
  i2c-nomadik: cosmetic coding style corrections
  i2c-au1550: dev_pm_ops conversion
  i2c-au1550: increase timeout waiting for master done
  i2c-au1550: remove unused ack_timeout
  i2c-au1550: remove usage of volatile keyword
  i2c-tegra: __iomem annotation fix
  i2c-eg20t: Add initialize processing in case i2c-error occurs
  i2c-eg20t: Fix flag setting issue
  i2c-eg20t: add stop sequence in case wait-event timeout occurs
  i2c-eg20t: Separate error processing
  i2c-eg20t: Fix 10bit access issue
  i2c-eg20t: Modify returned value s32 to long
  i2c-eg20t: Fix bus-idle waiting issue
  i2c-designware: Fix PCI core warning on suspend/resume
  i2c-designware: Add runtime power management support
  i2c-designware: Add support for Designware core behind PCI devices.
  i2c-designware: Push all register reads/writes into the core code.
  i2c-designware: Support multiple cores using same ISR
  ...

* 'for-linus' of git://opensource.wolfsonmicro.com/regulator: (22 commits)
  regulator: Constify constraints name
  regulator: Fix possible nullpointer dereference in regulator_enable()
  regulator: gpio-regulator add dependency on GENERIC_GPIO
  regulator: Add module.h include to gpio-regulator
  regulator: Add driver for gpio-controlled regulators
  regulator: remove duplicate REG_CTRL2 defines in tps65023
  regulator: Clarify documentation for regulator-regulator supplies
  regulator: Fix some bitrot in the machine driver documentation
  regulator: tps65023: Added support for the similiar TPS65020 chip
  regulator: tps65023: Setting correct core regulator for tps65021
  regulator: tps65023: Set missing bit for update core-voltage
  regulator: tps65023: Fixes i2c configuration issues
  regulator: Add debugfs file showing the supply map table
  regulator: tps6586x: add SMx slew rate setting
  regulator: tps65023: Fixes i2c configuration issues
  regulator: tps6507x: Remove num_voltages array
  regulator: max8952: removed unused mutex.
  regulator: fix regulator/consumer.h kernel-doc warning
  regulator: Ensure enough enable time for max8649
  regulator: 88pm8607: Fix off-by-one value range checking in the case of no id is matched
  ...

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: ohci: fix isochronous DMA synchronization
  firewire: ohci: work around selfID junk due to wrong gap count
  firewire: net: Use posted writes
  firewire: use clamp and min3 macros
  firewire: ohci: optimize TSB41BA3D detection
  firewire: ohci: TSB41BA3D support tweaks
  firewire: ohci: Add support for TSB41BA3D phy
  firewire: ohci: Move code from the bus reset tasklet into a workqueue
  firewire: sbp2: fold two functions into one
  firewire: sbp2: move some code to more sensible places
  firewire: sbp2: remove obsolete reference counting

* 'pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  pstore: make pstore write function return normal success/fail value
  pstore: change mutex locking to spin_locks
  pstore: defer inserting OOPS entries into pstore

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (62 commits)
  mlx4_core: Deprecate log_num_vlan module param
  IB/mlx4: Don't set VLAN in IBoE WQEs' control segment
  IB/mlx4: Enable 4K mtu for IBoE
  RDMA/cxgb4: Mark QP in error before disabling the queue in firmware
  RDMA/cxgb4: Serialize calls to CQ's comp_handler
  RDMA/cxgb3: Serialize calls to CQ's comp_handler
  IB/qib: Fix issue with link states and QSFP cables
  IB/mlx4: Configure extended active speeds
  mlx4_core: Add extended port capabilities support
  IB/qib: Hold links until tuning data is available
  IB/qib: Clean up checkpatch issue
  IB/qib: Remove s_lock around header validation
  IB/qib: Precompute timeout jiffies to optimize latency
  IB/qib: Use RCU for qpn lookup
  IB/qib: Eliminate divide/mod in converting idx to egr buf pointer
  IB/qib: Decode path MTU optimization
  IB/qib: Optimize RC/UC code by IB operation
  IPoIB: Use the right function to do DMA unmap pages
  RDMA/cxgb4: Use correct QID in insert_recv_cqe()
  RDMA/cxgb4: Make sure flush CQ entries are collected on connection close
  ...

Merge branches 'amso1100', 'cma', 'cxgb3', 'cxgb4', 'fdr', 'ipath', 'ipoib', 'misc', 'mlx4', 'misc', 'nes', 'qib' and 'xrc' into for-next

* git://github.com/herbertx/crypto: (48 commits)
  crypto: user - Depend on NET instead of selecting it
  crypto: user - Add dependency on NET
  crypto: talitos - handle descriptor not found in error path
  crypto: user - Initialise match in crypto_alg_match
  crypto: testmgr - add twofish tests
  crypto: testmgr - add blowfish test-vectors
  crypto: Make hifn_795x build depend on !ARCH_DMA_ADDR_T_64BIT
  crypto: twofish-x86_64-3way - fix ctr blocksize to 1
  crypto: blowfish-x86_64 - fix ctr blocksize to 1
  crypto: whirlpool - count rounds from 0
  crypto: Add userspace report for compress type algorithms
  crypto: Add userspace report for cipher type algorithms
  crypto: Add userspace report for rng type algorithms
  crypto: Add userspace report for pcompress type algorithms
  crypto: Add userspace report for nivaead type algorithms
  crypto: Add userspace report for aead type algorithms
  crypto: Add userspace report for givcipher type algorithms
  crypto: Add userspace report for ablkcipher type algorithms
  crypto: Add userspace report for blkcipher type algorithms
  crypto: Add userspace report for ahash type algorithms
  ...

In sysfs_rename we need to remove the optimization of not calling
sysfs_unlink_sibling and sysfs_link_sibling if the renamed parent
directory is not changing.  This optimization is no longer valid now
that sysfs dirents are stored in an rbtree sorted by name.

Move the assignment of s_ns before the call of sysfs_link_sibling.  With
no sysfs_dirent fields changing after the call of sysfs_link_sibling
this allows sysfs_link_sibling to take any of the directory entries into
account when it builds the rbtrees, and s_ns looks like a prime canidate
to be used in the rbtree in the future.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Greg KH <gregkh@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The board changes in the imx/devel branch conflict with other changes in
the device imx/dt branch.

Conflicts:
	arch/arm/mach-mx5/board-mx53_loco.c
	arch/arm/mach-mx5/board-mx53_smd.c
	arch/arm/plat-mxc/include/mach/common.h
	arch/arm/plat-mxc/include/mach/memory.h

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

This is the fifth version of the patchset (with one tiny whitespace fix)
to the Linux kernel to support the Qualcomm Hexagon architecture.

Between now and the next pull requests, Richard Kuo should have his key
signed, etc., and should be back on kernel.org.  In the meantime, this
got merged as a emailed patch-series.

* Hexagon: (36 commits)
  Add extra arch overrides to asm-generic/checksum.h
  Hexagon: Add self to MAINTAINERS
  Hexagon: Add basic stacktrace functionality for Hexagon architecture.
  Hexagon: Add configuration and makefiles for the Hexagon architecture.
  Hexagon: Comet platform support
  Hexagon: kgdb support files
  Hexagon: Add page-fault support.
  Hexagon: Add page table header files & etc.
  Hexagon: Add ioremap support
  Hexagon: Provide DMA implementation
  Hexagon: Implement basic TLB management routines for Hexagon.
  Hexagon: Implement basic cache-flush support
  Hexagon: Provide basic implementation and/or stubs for I/O routines.
  Hexagon: Add user access functions
  Hexagon: Add locking types and functions
  Hexagon: Add SMP support
  Hexagon: Provide basic debugging and system trap support.
  Hexagon: Add ptrace support
  Hexagon: Add time and timer functions
  Hexagon: Add interrupts
  ...

There are plausible reasons for architectures to provide their own
versions of csum_partial_copy_nocheck and csum_tcpudp_magic.
By protecting these, the architecture can still re-use the
asm-generic checksum.h, instead of copying it.

Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Mostly all stubs, as the TLB is managed by the hypervisor.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>