just use it to serialize the assignment
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Merge branch 'overlayfs.v25' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into for-linus

d_splice_alias() callers expect it to either stash the inode reference
into a new alias, or drop the inode reference.  That makes it possible
to just return d_splice_alias() result from ->lookup() instance, without
any extra housekeeping required.

Unfortunately, that should include the failure exits.  If d_splice_alias()
returns an error, it leaves the dentry it has been given negative and
thus it *must* drop the inode reference.  Easily fixed, but it goes way
back and will need backporting.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems.  Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack.  Initially the limit is set to 2.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Document the overlay filesystem.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

This is useful because of the stacking nature of overlayfs.  Users like to
find out (via /proc/mounts) which lower/upper directory were used at mount
time.

AV: even failing ovl_parse_opt() could've done some kstrdup()
AV: failure of ovl_alloc_entry() should end up with ENOMEM, not EINVAL
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Add support for statfs to the overlayfs filesystem.  As the upper layer
is the target of all write operations assume that the space in that
filesystem is the space in the overlayfs.  There will be some inaccuracy as
overwriting a file will copy it up and consume space we were not expecting,
but it is better than nothing.

Use the upper layer dentry and mount from the overlayfs root inode,
passing the statfs call to that filesystem.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Overlayfs allows one, usually read-write, directory tree to be
overlaid onto another, read-only directory tree.  All modifications
go to the upper, writable layer.

This type of mechanism is most often used for live CDs but there's a
wide variety of other uses.

The implementation differs from other "union filesystem"
implementations in that after a file is opened all operations go
directly to the underlying, lower or upper, filesystems.  This
simplifies the implementation and allows native performance in these
cases.

The dentry tree is duplicated from the underlying filesystems, this
enables fast cached lookups without adding special support into the
VFS.  This uses slightly more memory than union mounts, but dentries
are relatively small.

Currently inodes are duplicated as well, but it is a possible
optimization to share inodes for non-directories.

Opening non directories results in the open forwarded to the
underlying filesystem.  This makes the behavior very similar to union
mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file
descriptors).

Usage:

  mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay

The following cotributions have been folded into this patch:

Neil Brown <neilb@suse.de>:
 - minimal remount support
 - use correct seek function for directories
 - initialise is_real before use
 - rename ovl_fill_cache to ovl_dir_read

Felix Fietkau <nbd@openwrt.org>:
 - fix a deadlock in ovl_dir_read_merged
 - fix a deadlock in ovl_remove_whiteouts

Erez Zadok <ezk@fsl.cs.sunysb.edu>
 - fix cleanup after WARN_ON

Sedat Dilek <sedat.dilek@googlemail.com>
 - fix up permission to confirm to new API

Robin Dong <hao.bigrat@gmail.com>
 - fix possible leak in ovl_new_inode
 - create new inode in ovl_link

Andy Whitcroft <apw@canonical.com>
 - switch to __inode_permission()
 - copy up i_uid/i_gid from the underlying inode

AV:
 - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits
 - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(),
   lack of check for udir being the parent of upper, dropping and regaining
   the lock on udir (which would require _another_ check for parent being
   right).
 - bogus d_drop() in copyup and rename [fix from your mail]
 - copyup/remove and copyup/rename races [fix from your mail]
 - ovl_dir_fsync() leaving ERR_PTR() in ->realfile
 - ovl_entry_free() is pointless - it's just a kfree_rcu()
 - fold ovl_do_lookup() into ovl_lookup()
 - manually assigning ->d_op is wrong.  Just use ->s_d_op.
 [patches picked from Miklos]:
 * copyup/remove and copyup/rename races
 * bogus d_drop() in copyup and rename

Also thanks to the following people for testing and reporting bugs:

  Jordi Pujol <jordipujolp@gmail.com>
  Andy Whitcroft <apw@canonical.com>
  Michal Suchanek <hramrach@centrum.cz>
  Felix Fietkau <nbd@openwrt.org>
  Erez Zadok <ezk@fsl.cs.sunysb.edu>
  Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Allocate a dentry, initialize it with a whiteout and hash it in the place
of the old dentry.  Later the old dentry will be moved away and the
whiteout will remain.

i_mutex protects agains concurrent readdir.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Hugh Dickins <hughd@google.com>

Add whiteout support to ext4_rename().  A whiteout inode (chrdev/0,0) is
created before the rename takes place.  The whiteout inode is added to the
old entry instead of deleting it.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

This adds a new RENAME_WHITEOUT flag.  This flag makes rename() create a
whiteout of source.  The whiteout creation is atomic relative to the
rename.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Whiteout isn't actually a new file type, but is represented as a char
device (Linus's idea) with 0/0 device number.

This has several advantages compared to introducing a new whiteout file
type:

 - no userspace API changes (e.g. trivial to make backups of upper layer
   filesystem, without losing whiteouts)

 - no fs image format changes (you can boot an old kernel/fsck without
   whiteout support and things won't break)

 - implementation is trivial
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

It's already duplicated in btrfs and about to be used in overlayfs too.

Move the sticky bit check to an inline helper and call the out-of-line
helper only in the unlikly case of the sticky bit being set.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Overlayfs needs a private clone of the mount, so create a function for
this and export to modules.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

We need to be able to check inode permissions (but not filesystem implied
permissions) for stackable filesystems.  Expose this interface for overlayfs.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Export do_splice_direct() to modules.  Needed by overlay filesystem.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Add a new inode operation i_op->dentry_open().  This is for stacked filesystems
that want to return a struct file from a different filesystem.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Pull ARM SoC fixes from Olof Johansson:
 "A batch of fixes that have come in during the merge window.

  Some of them are defconfig updates for things that have now landed,
  some errata additions and a few general scattered fixes.

  There's also a qcom DT update that adds support for SATA on AP148, and
  basic support for Sony Xperia Z1 and CM-QS600 platforms that seemed
  isolated enough that we could merge it even if it's late"

* tag 'arm-soc-fixes-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  MAINTAINERS: corrected bcm2835 search
  ARM: dts: Explicitly set dr_mode on exynos5420-arndale-octa
  ARM: dts: Explicitly set dr_mode on exynos Peach boards
  ARM: dts: qcom: add CM-QS600 board
  ARM: dts: qcom: Add initial DTS file for Sony Xperia Z1 phone
  ARM: dts: qcom: Add SATA support on IPQ8064/AP148
  MAINTAINERS: Update Santosh Shilimkar's email id
  ARM: sunxi_defconfig: enable CONFIG_REGULATOR
  ARM: dts: Disable smc91x on n900 until bootloader dependency is removed
  ARM: omap2plus_defconfig: Enable ARM erratum 430973 for omap3
  ARM: exynos_defconfig: enable USB gadget support
  ARM: exynos_defconfig: Enable Maxim 77693 and I2C GPIO drivers
  ARM: mm: Fix ifdef around cpu_*_do_[suspend, resume] ops
  ARM: EXYNOS: Fix build with PM_SLEEP=n and ARM_EXYNOS_CPUIDLE=n
  ARM: SAMSUNG: Restore Samsung PM Debug functionality
  ARM: dts: Fix pull setting in sd4_width8 pin group for exynos4x12
  ARM: exynos_defconfig: Enable SBS battery support
  ARM: exynos_defconfig: Enable Control Groups support
  ARM: exynos_defconfig: Enable Atmel maXTouch support
  ARM: exynos_defconfig: Enable MAX77802

Pull audit updates from Eric Paris:
 "So this change across a whole bunch of arches really solves one basic
  problem.  We want to audit when seccomp is killing a process.  seccomp
  hooks in before the audit syscall entry code.  audit_syscall_entry
  took as an argument the arch of the given syscall.  Since the arch is
  part of what makes a syscall number meaningful it's an important part
  of the record, but it isn't available when seccomp shoots the
  syscall...

  For most arch's we have a better way to get the arch (syscall_get_arch)
  So the solution was two fold: Implement syscall_get_arch() everywhere
  there is audit which didn't have it.  Use syscall_get_arch() in the
  seccomp audit code.  Having syscall_get_arch() everywhere meant it was
  a useless flag on the stack and we could get rid of it for the typical
  syscall entry.

  The other changes inside the audit system aren't grand, fixed some
  records that had invalid spaces.  Better locking around the task comm
  field.  Removing some dead functions and structs.  Make some things
  static.  Really minor stuff"

* git://git.infradead.org/users/eparis/audit: (31 commits)
  audit: rename audit_log_remove_rule to disambiguate for trees
  audit: cull redundancy in audit_rule_change
  audit: WARN if audit_rule_change called illegally
  audit: put rule existence check in canonical order
  next: openrisc: Fix build
  audit: get comm using lock to avoid race in string printing
  audit: remove open_arg() function that is never used
  audit: correct AUDIT_GET_FEATURE return message type
  audit: set nlmsg_len for multicast messages.
  audit: use union for audit_field values since they are mutually exclusive
  audit: invalid op= values for rules
  audit: use atomic_t to simplify audit_serial()
  kernel/audit.c: use ARRAY_SIZE instead of sizeof/sizeof[0]
  audit: reduce scope of audit_log_fcaps
  audit: reduce scope of audit_net_id
  audit: arm64: Remove the audit arch argument to audit_syscall_entry
  arm64: audit: Add audit hook in syscall_trace_enter/exit()
  audit: x86: drop arch from __audit_syscall_entry() interface
  sparc: implement is_32bit_task
  sparc: properly conditionalize use of TIF_32BIT
  ...

Merge tag 'qcom-dt-for-3.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/galak/linux-qcom into fixes

Merge "qcom DT changes for v3.18-3" from Kumar Gala:

Qualcomm ARM Based Device Tree Updates for v3.18-3

* Added Board support for CM-QS600 and Sony Xperia Z1 phone
* Added SATA support on IPQ8064/AP148

* tag 'qcom-dt-for-3.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/galak/linux-qcom:
  ARM: dts: qcom: add CM-QS600 board
  ARM: dts: qcom: Add initial DTS file for Sony Xperia Z1 phone
  ARM: dts: qcom: Add SATA support on IPQ8064/AP148

Merge tag 'samsung-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung into fixes

Pull more fixes from Kukjin Kim:

2nd Samsung fixes for v3.18
- Explicitly set dr_mode on exynos5800-peach-pi, exynos5420-peach-pit
  and exynos5420-arndale-octa boards, because the USB dwc3 controller
  will not work properly without dr_mode as host on above boards if
  the USB host and gadget are enabled in kernel configuration both.

* tag 'samsung-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
  ARM: dts: Explicitly set dr_mode on exynos5420-arndale-octa
  ARM: dts: Explicitly set dr_mode on exynos Peach boards
Signed-off-by: Olof Johansson <olof@lixom.net>

Corrected bcm2835 maintainer info by using N: to specify any files with
bcm2835 in are directed to the proper maintainer.
Also corrected minor mispelling of ARCHITECTURE in 2 comment locations.
Signed-off-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

Pull ntb (non-transparent bridge) updates from Jon Mason:
 "Add support for Haswell NTB split BARs, a debugfs entry for basic
  debugging info, and some code clean-ups"

* tag 'ntb-3.18' of git://github.com/jonmason/ntb:
  ntb: Adding split BAR support for Haswell platforms
  ntb: use errata flag set via DID to implement workaround
  ntb: conslidate reading of PPD to move platform detection earlier
  ntb: move platform detection to separate function
  NTB: debugfs device entry

Pull i2c updates from Wolfram Sang:
 "Highlights from the I2C subsystem for 3.18:

   - new drivers for Axxia AM55xx, and Hisilicon hix5hd2 SoC.

   - designware driver gained AMD support, exynos gained exynos7 support

  The rest is usual driver stuff.  Hopefully no lowlights this time"

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: i801: Add Device IDs for Intel Sunrise Point PCH
  i2c: hix5hd2: add i2c controller driver
  i2c-imx: Disable the clock on probe failure
  i2c: designware: Add support for AMD I2C controller
  i2c: designware: Rework probe() to get clock a bit later
  i2c: designware: Default to fast mode in case of ACPI
  i2c: axxia: Add I2C driver for AXM55xx
  i2c: exynos: add support for HSI2C module on Exynos7
  i2c: mxs: detect No Slave Ack on SELECT in PIO mode
  i2c: cros_ec: Remove EC_I2C_FLAG_10BIT
  i2c: cros-ec-tunnel: Add of match table
  i2c: rcar: remove sign-compare flaw
  i2c: ismt: Use minimum descriptor size
  i2c: imx: Add arbitration lost check
  i2c: rk3x: Remove unlikely() annotations
  i2c: rcar: check for no IRQ in rcar_i2c_irq()
  i2c: rcar: make rcar_i2c_prepare_msg() *void*
  i2c: rcar: simplify check for last message
  i2c: designware: add support of platform data to set I2C mode
  i2c: designware: add support of I2C standard mode

Pull sound fixes from Takashi Iwai:
 "Here are a collection of small fixes after 3.18 merge.

  The urgent one is the fix for kernel panics with linked PCM substream
  triggered by the recent nonatomic PCM ops support.  Other two fixes
  (emu10k1 and bebob) are stable fixes, and one easy PCI ID addition for
  a new Intel HD-audio controller"

* tag 'sound-fix-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda_intel: Add Device IDs for Intel Sunrise Point PCH
  ALSA: emu10k1: Fix deadlock in synth voice lookup
  ALSA: pcm: Fix referred substream in snd_pcm_action_group() unlock loop
  ALSA: bebob: Fix failure to detect source of clock for Terratec Phase 88

Pull second round of input updates from Dmitry Torokhov:
 "Mostly simple bug fixes, although we do have one brand new driver for
  Microchip AR1021 i2c touchscreen.

  Also there is the change to stop trying to use i8042 active
  multiplexing by default (it is still possible to activate it via
  i8042.nomux=0 on boxes that implement it)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: xpad - add Thrustmaster as Xbox 360 controller vendor
  Input: xpad - add USB ID for Thrustmaster Ferrari 458 Racing Wheel
  Input: max77693-haptic - fix state check in imax77693_haptic_disable()
  Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend
  Input: alps - fix v4 button press recognition
  Input: i8042 - disable active multiplexing by default
  Input: i8042 - add noloop quirk for Asus X750LN
  Input: synaptics - gate forcepad support by DMI check
  Input: Add Microchip AR1021 i2c touchscreen
  Input: cros_ec_keyb - add of match table
  Input: serio - avoid negative serio device numbers
  Input: avoid negative input device numbers
  Input: automatically set EV_ABS bit in input_set_abs_params
  Input: adp5588-keys - cancel workqueue in failure path
  Input: opencores-kbd - switch to using managed resources
  Input: evdev - fix EVIOCG{type} ioctl

Pull infiniband/RDMA updates from Roland Dreier:
 - large set of iSER initiator improvements
 - hardware driver fixes for cxgb4, mlx5 and ocrdma
 - small fixes to core midlayer

* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (47 commits)
  RDMA/cxgb4: Fix ntuple calculation for ipv6 and remove duplicate line
  RDMA/cxgb4: Add missing neigh_release in find_route
  RDMA/cxgb4: Take IPv6 into account for best_mtu and set_emss
  RDMA/cxgb4: Make c4iw_wr_log_size_order static
  IB/core: Fix XRC race condition in ib_uverbs_open_qp
  IB/core: Clear AH attr variable to prevent garbage data
  RDMA/ocrdma: Save the bit environment, spare unncessary parenthesis
  RDMA/ocrdma: The kernel has a perfectly good BIT() macro - use it
  RDMA/ocrdma: Don't memset() buffers we just allocated with kzalloc()
  RDMA/ocrdma: Remove a unused-label warning
  RDMA/ocrdma: Convert kernel VA to PA for mmap in user
  RDMA/ocrdma: Get vlan tag from ib_qp_attrs
  RDMA/ocrdma: Add default GID at index 0
  IB/mlx5, iser, isert: Add Signature API additions
  Target/iser: Centralize ib_sig_domain setting
  IB/iser: Centralize ib_sig_domain settings
  IB/mlx5: Use extended internal signature layout
  IB/iser: Set IP_CSUM as default guard type
  IB/iser: Remove redundant assignment
  IB/mlx5: Use enumerations for PI copy mask
  ...

Pull more perf updates from Ingo Molnar:
 "A second (and last) round of late coming fixes and changes, almost all
  of them in perf tooling:

  User visible tooling changes:

   - Add period data column and make it default in 'perf script' (Jiri
     Olsa)

   - Add a visual cue for toggle zeroing of samples in 'perf top'
     (Taeung Song)

   - Improve callchains when using libunwind (Namhyung Kim)

  Tooling fixes and infrastructure changes:

   - Fix for double free in 'perf stat' when using some specific invalid
     command line combo (Yasser Shalabi)

   - Fix off-by-one bugs in map->end handling (Stephane Eranian)

   - Fix off-by-one bug in maps__find(), also related to map->end
     handling (Namhyung Kim)

   - Make struct symbol->end be the first addr after the symbol range,
     to make it match the convention used for struct map->end.  (Arnaldo
     Carvalho de Melo)

   - Fix perf_evlist__add_pollfd() error handling in 'perf kvm stat
     live' (Jiri Olsa)

   - Fix python test build by moving callchain_param to an object linked
     into the python binding (Jiri Olsa)

   - Document sysfs events/ interfaces (Cody P Schafer)

   - Fix typos in perf/Documentation (Masanari Iida)

   - Add missing 'struct option' forward declaration (Arnaldo Carvalho
     de Melo)

   - Add option to copy events when queuing for sorting across cpu
     buffers and enable it for 'perf kvm stat live', to avoid having
     events left in the queue pointing to the ring buffer be rewritten
     in high volume sessions.  (Alexander Yarygin, improving work done
     by David Ahern):

   - Do not include a struct hists per perf_evsel, untangling the
     histogram code from perf_evsel, to pave the way for exporting a
     minimalistic tools/lib/api/perf/ library usable by tools/perf and
     initially by the rasd daemon being developed by Borislav Petkov,
     Robert Richter and Jean Pihet.  (Arnaldo Carvalho de Melo)

   - Make perf_evlist__open(evlist, NULL, NULL), i.e. without cpu and
     thread maps mean syswide monitoring, reducing the boilerplate for
     tools that only want system wide mode.  (Arnaldo Carvalho de Melo)

   - Move exit stuff from perf_evsel__delete to perf_evsel__exit, delete
     should be just a front end for exit + free (Arnaldo Carvalho de
     Melo)

   - Add support to new style format of kernel PMU event.  (Kan Liang)

  and other misc fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
  perf script: Add period as a default output column
  perf script: Add period data column
  perf evsel: No need to drag util/cgroup.h
  perf evlist: Add missing 'struct option' forward declaration
  perf evsel: Move exit stuff from __delete to __exit
  kprobes/x86: Remove stale ARCH_SUPPORTS_KPROBES_ON_FTRACE define
  perf kvm stat live: Enable events copying
  perf session: Add option to copy events when queueing
  perf Documentation: Fix typos in perf/Documentation
  perf trace: Use thread_{,_set}_priv helpers
  perf kvm: Use thread_{,_set}_priv helpers
  perf callchain: Create an address space per thread
  perf report: Set callchain_param.record_mode for future use
  perf evlist: Fix for double free in tools/perf stat
  perf test: Add test case for pmu event new style format
  perf tools: Add support to new style format of kernel PMU event
  perf tools: Parse the pmu event prefix and suffix
  Revert "perf tools: Default to cpu// for events v5"
  perf Documentation: Remove Ruplicated docs for powerpc cpu specific events
  perf Documentation: sysfs events/ interfaces
  ...

Pull sparc fixes from David Miller:
 "Here we have two bug fixes:

  1) The current thread's fault_code is not setup properly upon entry to
     do_sparc64_fault() in some paths, leading to spurious SIGBUS.

  2) Don't use a zero length array at the end of thread_info on sparc64,
     otherwise end_of_stack() isn't right"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Do not define thread fpregs save area as zero-length array.
  sparc64: Fix corrupted thread fault code.

Pull networking fixes from David Miller:
 "A quick batch of bug fixes:

  1) Fix build with IPV6 disabled, from Eric Dumazet.

  2) Several more cases of caching SKB data pointers across calls to
     pskb_may_pull(), thus referencing potentially free'd memory.  From
     Li RongQing.

  3) DSA phy code tests operation presence improperly, instead of going:

        if (x->ops->foo)
                r = x->ops->foo(args);

     it was going:

        if (x->ops->foo(args))
                r = x->ops->foo(args);

   Fix from Andew Lunn"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  Net: DSA: Fix checking for get_phy_flags function
  ipv6: fix a potential use after free in sit.c
  ipv6: fix a potential use after free in ip6_offload.c
  ipv4: fix a potential use after free in gre_offload.c
  tcp: fix build error if IPv6 is not enabled

The check for the presence or not of the optional switch function
get_phy_flags() called the function, rather than checked to see if it
is a NULL pointer. This causes a derefernce of a NULL pointer on all
switch chips except the sf2, the only switch to implement this call.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Fixes: 6819563e ("net: dsa: allow switch drivers to specify phy_device::dev_flags")
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This breaks the stack end corruption detection facility.

What that facility does it write a magic value to "end_of_stack()"
and checking to see if it gets overwritten.

"end_of_stack()" is "task_thread_info(p) + 1", which for sparc64 is
the beginning of the FPU register save area.

So once the user uses the FPU, the magic value is overwritten and the
debug checks trigger.

Fix this by making the size explicit.

Due to the size we use for the fpsaved[], gsr[], and xfsr[] arrays we
are limited to 7 levels of FPU state saves.  So each FPU register set
is 256 bytes, allocate 256 * 7 for the fpregs area.
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>

Every path that ends up at do_sparc64_fault() must install a valid
FAULT_CODE_* bitmask in the per-thread fault code byte.

Two paths leading to the label winfix_trampoline (which expects the
FAULT_CODE_* mask in register %g4) were not doing so:

1) For pre-hypervisor TLB protection violation traps, if we took
   the 'winfix_trampoline' path we wouldn't have %g4 initialized
   with the FAULT_CODE_* value yet.  Resulting in using the
   TLB_TAG_ACCESS register address value instead.

2) In the TSB miss path, when we notice that we are going to use a
   hugepage mapping, but we haven't allocated the hugepage TSB yet, we
   still have to take the window fixup case into consideration and
   in that particular path we leave %g4 not setup properly.

Errors on this sort were largely invisible previously, but after
commit 4ccb9272 ("sparc64: sun4v TLB
error power off events") we now have a fault_code mask bit
(FAULT_CODE_BAD_RA) that triggers due to this bug.

FAULT_CODE_BAD_RA triggers because this bit is set in TLB_TAG_ACCESS
(see #1 above) and thus we get seemingly random bus errors triggered
for user processes.

Fixes: 4ccb9272 ("sparc64: sun4v TLB error power off events")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull slave-dmaengine updates from Vinod Koul:
 "For dmaengine contributions we have:
   - designware cleanup by Andy
   - my series moving device_control users to dmanegine_xxx APIs for
     later removal of device_control API
   - minor fixes spread over drivers mainly mv_xor, pl330, mmp, imx-sdma
     etc"

* 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma: (60 commits)
  serial: atmel: add missing dmaengine header
  dmaengine: remove FSLDMA_EXTERNAL_START
  dmaengine: freescale: remove FSLDMA_EXTERNAL_START control method
  carma-fpga: move to fsl_dma_external_start()
  carma-fpga: use dmaengine_xxx() API
  dmaengine: freescale: add and export fsl_dma_external_start()
  dmaengine: add dmaengine_prep_dma_sg() helper
  video: mx3fb: use dmaengine_terminate_all() API
  serial: sh-sci: use dmaengine_terminate_all() API
  net: ks8842: use dmaengine_terminate_all() API
  mtd: sh_flctl: use dmaengine_terminate_all() API
  mtd: fsmc_nand: use dmaengine_terminate_all() API
  V4L2: mx3_camer: use dmaengine_pause() API
  dmaengine: coh901318: use dmaengine_terminate_all() API
  pata_arasan_cf: use dmaengine_terminate_all() API
  dmaengine: edma: check for echan->edesc => NULL in edma_dma_pause()
  dmaengine: dw: export probe()/remove() and Co to users
  dmaengine: dw: enable and disable controller when needed
  dmaengine: dw: always export dw_dma_{en,dis}able
  dmaengine: dw: introduce dw_dma_on() helper
  ...

Pull fbdev updates from Tomi Valkeinen:
 - new 6x10 font
 - various small fixes and cleanups

* tag 'fbdev-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux: (30 commits)
  fonts: Add 6x10 font
  videomode: provide dummy inline functions for !CONFIG_OF
  video/atmel_lcdfb: Introduce regulator support
  fbdev: sh_mobile_hdmi: Re-init regs before irq re-enable on resume
  framebuffer: fix screen corruption when copying
  framebuffer: fix border color
  arm, fbdev, omap2, LLVMLinux: Remove nested function from omapfb
  arm, fbdev, omap2, LLVMLinux: Remove nested function from omap2 dss
  video: fbdev: valkyriefb.c: use container_of to resolve fb_info_valkyrie from fb_info
  video: fbdev: pxafb.c: use container_of to resolve pxafb_info/layer from fb_info
  video: fbdev: cyber2000fb.c: use container_of to resolve cfb_info from fb_info
  video: fbdev: controlfb.c: use container_of to resolve fb_info_control from fb_info
  video: fbdev: sa1100fb.c: use container_of to resolve sa1100fb_info from fb_info
  video: fbdev: stifb.c: use container_of to resolve stifb_info from fb_info
  video: fbdev: sis: sis_main.c: Cleaning up missing null-terminate in conjunction with strncpy
  video: valkyriefb: Fix unused variable warning in set_valkyrie_clock()
  video: fbdev: use %*ph specifier to dump small buffers
  video: mx3fb: always enable BACKLIGHT_LCD_SUPPORT
  video: fbdev: au1200fb: delete double assignment
  video: fbdev: sis: delete double assignment
  ...

Pull second batch of changes for KVM/{arm,arm64} from Marc Zyngier:
 "The most obvious thing is the sizeable MMU changes to support 48bit
  VAs on arm64.

  Summary:

   - support for 48bit IPA and VA (EL2)
   - a number of fixes for devices mapped into guests
   - yet another VGIC fix for BE
   - a fix for CPU hotplug
   - a few compile fixes (disabled VGIC, strict mm checks)"

[ I'm pulling directly from Marc at the request of Paolo Bonzini, whose
  backpack was stolen at Düsseldorf airport and will do new keys and
  rebuild his web of trust.    - Linus ]

* tag 'kvm-arm-for-3.18-take-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm:
  arm/arm64: KVM: Fix BE accesses to GICv2 EISR and ELRSR regs
  arm: kvm: STRICT_MM_TYPECHECKS fix for user_mem_abort
  arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE
  arm64: KVM: Implement 48 VA support for KVM EL2 and Stage-2
  arm/arm64: KVM: map MMIO regions at creation time
  arm64: kvm: define PAGE_S2_DEVICE as read-only by default
  ARM: kvm: define PAGE_S2_DEVICE as read-only by default
  arm/arm64: KVM: add 'writable' parameter to kvm_phys_addr_ioremap
  arm/arm64: KVM: fix potential NULL dereference in user_mem_abort()
  arm/arm64: KVM: use __GFP_ZERO not memset() to get zeroed pages
  ARM: KVM: fix vgic-disabled build
  arm: kvm: fix CPU hotplug

Pull MIPS updates from Ralf Baechle:
 "This is the MIPS pull request for the next kernel:

   - Zubair's patch series adds CMA support for MIPS.  Doing so it also
     touches ARM64 and x86.
   - remove the last instance of IRQF_DISABLED from arch/mips
   - updates to two of the MIPS defconfig files.
   - cleanup of how cache coherency bits are handled on MIPS and
     implement support for write-combining.
   - platform upgrades for Alchemy
   - move MIPS DTS files to arch/mips/boot/dts/"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (24 commits)
  MIPS: ralink: remove deprecated IRQF_DISABLED
  MIPS: pgtable.h: Implement the pgprot_writecombine function for MIPS
  MIPS: cpu-probe: Set the write-combine CCA value on per core basis
  MIPS: pgtable-bits: Define the CCA bit for WC writes on Ingenic cores
  MIPS: pgtable-bits: Move the CCA bits out of the core's ifdef blocks
  MIPS: DMA: Add cma support
  x86: use generic dma-contiguous.h
  arm64: use generic dma-contiguous.h
  asm-generic: Add dma-contiguous.h
  MIPS: BPF: Add new emit_long_instr macro
  MIPS: ralink: Move device-trees to arch/mips/boot/dts/
  MIPS: Netlogic: Move device-trees to arch/mips/boot/dts/
  MIPS: sead3: Move device-trees to arch/mips/boot/dts/
  MIPS: Lantiq: Move device-trees to arch/mips/boot/dts/
  MIPS: Octeon: Move device-trees to arch/mips/boot/dts/
  MIPS: Add support for building device-tree binaries
  MIPS: Create common infrastructure for building built-in device-trees
  MIPS: SEAD3: Enable DEVTMPFS
  MIPS: SEAD3: Regenerate defconfigs
  MIPS: Alchemy: DB1300: Add touch penirq support
  ...

Pull powerpc fix from Michael Ellerman:
 "There was a bit of a misunderstanding between us and the ARM guys in
  the device tree PCI code, which is breaking virtio on powerpc.

  This is the minimal fix until we can sort it out properly"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
  powerpc/pci: Fix IO space breakage after of_pci_range_to_resource() change

Pull cifs/smb3 updates from Steve French:
 "Improved SMB3 support (symlink and device emulation, and remapping by
  default the 7 reserved posix characters) and a workaround for cifs
  mounts to Mac (working around a commonly encountered Mac server bug)"

* 'for-linus' of git://git.samba.org/sfrench/cifs-2.6:
  [CIFS] Remove obsolete comment
  Check minimum response length on query_network_interface
  Workaround Mac server problem
  Remap reserved posix characters by default (part 3/3)
  Allow conversion of characters in Mac remap range (part 2)
  Allow conversion of characters in Mac remap range. Part 1
  mfsymlinks support for SMB2.1/SMB3. Part 2 query symlink
  Add mfsymlinks support for SMB2.1/SMB3. Part 1 create symlink
  Allow mknod and mkfifo on SMB2/SMB3 mounts
  add defines for two new file attributes