Erratum Hisilicon-161010101 says that the ARM generic timer counter "has
the potential to contain an erroneous value when the timer value
changes". Accesses to TVAL (both read and write) are also affected due
to the implicit counter read. Accesses to CVAL are not affected.

The workaround is to reread the system count registers until the value
of the second read is larger than the first one by less than 32, the
system counter can be guaranteed not to return wrong value twice by
back-to-back read and the error value is always larger than the correct
one by 32. Writes to TVAL are replaced with an equivalent write to CVAL.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, fix Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Currently we have code inline in the arch timer probe path to cater for
Freescale erratum A-008585, complete with ifdeffery. This is a little
ugly, and will get worse as we try to add more errata handling.

This patch refactors the handling of Freescale erratum A-008585. Now the
erratum is described in a generic arch_timer_erratum_workaround
structure, and the probe path can iterate over these to detect errata
and enable workarounds.

This will simplify the addition and maintenance of code handling
Hisilicon erratum 161010101.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, correct Kconfig, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Having a command line option to flip the errata handling for a
particular erratum is a little bit unusual, and it's vastly superior to
pass this in the DT. By common consensus, it's best to kill off the
command line parameter.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[Mark: split patch, reword commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

This erratum describes a bug in logic outside the core, so MIDR can't be
used to identify its presence, and reading an SoC-specific revision
register from common arch timer code would be awkward.  So, describe it
in the device tree.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

This patch adds a OSTM driver for the Renesas architecture.
The OS Timer (OSTM) has independent channels that can be
used as a freerun or interval times.
This driver uses the first probed device as a clocksource
and then any additional devices as clock events.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

On newer boards the TC can be read as single 32 bit value without locking.
Thus the clock can be used as reference for sched_clock which is much more
accurate than the jiffies implementation.

Tested on a Atmel SAMA5D2 board.
Signed-off-by: David Engraf <david.engraf@sysgo.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

This is a rewrite of the Gemini timer
driver in arch/arm/mach-gemini/timer.c trying to do everything
the device tree way:

- Make every IO-access relative to a base address and dynamic
  so we can do a dynamic ioremap and get going.
- Do not poke around directly in the global syscon registers,
  access them using the syscon regmap style design pattern for
  the one register we need to check.
- Find register range and interrupt from the device tree.

Cc: Janos Laube <janos.dev@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

This adds device tree bindings for the Cortina Systems Gemini
timer block used in these SoCs.

Cc: Janos Laube <janos.dev@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

The current code uses the CLOCKSOURCE_OF_DECLARE macro to fill the clksrc
table with a t-uple (name, init_function).

Unfortunately it ends up to the clockevent and the clocksource being
both initialized with this macro. It is not a problem by itself but there
is not a clear distinction between a clockevent and a clocksource in the
code initialization path. Somebody can argue there are the same IP block
and the same DT node. But conceptually from the software side, there are
two distincts entities and as is they should be initialized separetely.
Some drivers which do not have a clocksource end up by using the
CLOCKSOURCE_OF_DECLARE macro to declare a clockevent.

Another result is the fuzzy organization in the clocksource directory,
where the clockevents are implemented in the same file than the
clocksources or file labelled timer-something implementing a clocksource.

This patch provides another macro to specifically declare a clockevent in
the same way than the clocksource and gives the opportunity to write two
separate drivers, one for the clocksource and another for the clockevents.

Hopefully, that can help to do some housework in the directory, perhaps
split the drivers in to entities, for example:
	- clksrc-rockchip.c
	- clkevt-rockchip.c

Also, it gives the possibility to declare clocksources separately in the
DT and then use a clocksource from IP block while while clockevents are
used from another IP block.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

It was observed that on an Intel x86 system without the ARAT (Always
running APIC timer) feature and with fairly large number of CPUs as
well as CPUs coming in and out of intel_idle frequently, the lock
contention on the tick_broadcast_lock can become significant.

To reduce contention, the lock is put into its own cacheline and all
the cpumask_var_t variables are put into the __read_mostly section.

Running the SP benchmark of the NAS Parallel Benchmarks on a 4-socket
16-core 32-thread Nehalam system, the performance number improved
from 3353.94 Mop/s to 3469.31 Mop/s when this patch was applied on
a 4.9.6 kernel.  This is a 3.4% improvement.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1485799063-20857-1-git-send-email-longman@redhat.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

Merge branch 'fortglx/4.11/time' of https://git.linaro.org/people/john.stultz/linux into timers/core

 - Remove unused functions
 - Document udelay inaccuracy
 - Remove posix timer data from task struct when posix timers are off

When CONFIG_POSIX_TIMERS is disabled, it is preferable to remove related
structures from struct task_struct and struct signal_struct as they
won't contain anything useful and shouldn't be relied upon by mistake.
Code still referencing those structures is also disabled here.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>

When a panic happens during bootup, "Rebooting in X seconds.." is
shown, but reboot happens immediatelly. It is because panic() uses mdelay()
and mdelay() calls __const_udelay() immediately, which does not
work while booting.

The per_cpu cpu_info.loops_per_jiffy value is not initialized yet, so
__const_udelay() actually multiplies the number of loops by zero. This
results in __const_udelay() to delay the execution only by a nanosecond
or so.

So check whether cpu_info.loops_per_jiffy is zero and use
loops_per_jiffy in that case. mdelay() will not be so precise without
proper calibration, but it works relatively well.

Before:

  [    0.170039] delaying 100ms
  [    0.170828] done

After

  [    0.214042] delaying 100ms
  [    0.313974] done

I do not think the added check matters given we are about to spin the
processor in the next few hundred cycles.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170119114730.2670-1-jslaby@suse.cz
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

There seems to be some misunderstanding that udelay() and friends will
always guarantee the specified delay.  This is a false understanding.
When udelay() is based on CPU cycles, it can return early for many
reasons which are detailed by Linus' reply to me in a thread in 2011:

  http://lists.openwall.net/linux-kernel/2011/01/12/372

However, a udelay test module was created in 2014 which allows udelay()
to only be 0.5% fast, which is outside of the CPU-cycles udelay()
results I measured back in 2011, which were deemed to be in the "we
don't care" region.

test_udelay() should be fixed to reflect the real allowable tolerance
on udelay(), rather than 0.5%.

Cc: David Riley <davidriley@chromium.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: John Stultz <john.stultz@linaro.org>

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/0d5cf199ac43792df0b6f7e2145545c30fa1dbbe.1482222135.git.geliangtang@gmail.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

It turns out that while GCC-4.4 manages to generate 32x32->64 mult
instructions for the 32bit mul_u64_u32_shr() code, any GCC after that
fails horribly.

Fix this by providing an explicit mul_u32_u32() function which can be
architcture provided.
Reported-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: Liav Rehana <liavr@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161209083011.GD15765@worktop.programming.kicks-ass.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

Pull btrfs fixes from Chris Mason:
 "These are all over the place.

  The tracepoint part of the pull fixes a crash and adds a little more
  information to two tracepoints, while the rest are good old fashioned
  fixes"

* 'for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: make tracepoint format strings more compact
  Btrfs: add truncated_len for ordered extent tracepoints
  Btrfs: add 'inode' for extent map tracepoint
  btrfs: fix crash when tracepoint arguments are freed by wq callbacks
  Btrfs: adjust outstanding_extents counter properly when dio write is split
  Btrfs: fix lockdep warning about log_mutex
  Btrfs: use down_read_nested to make lockdep silent
  btrfs: fix locking when we put back a delayed ref that's too new
  btrfs: fix error handling when run_delayed_extent_op fails
  btrfs: return the actual error value from  from btrfs_uuid_tree_iterate

Pull ceph fixes from Ilya Dryomov:
 "Two small fixups for the filesystem changes that went into this merge
  window"

* tag 'ceph-for-4.10-rc4' of git://github.com/ceph/ceph-client:
  ceph: fix get_oldest_context()
  ceph: fix mds cluster availability check

Pull VFIO fixes from Alex Williamson:

 - Cleanups and bug fixes for the mtty sample driver (Dan Carpenter)

 - Export and make use of has_capability() to fix incorrect use of
   ns_capable() for testing task capabilities (Jike Song)

* tag 'vfio-v4.10-rc4' of git://github.com/awilliam/linux-vfio:
  vfio/type1: Remove pid_namespace.h include
  vfio iommu type1: fix the testing of capability for remote task
  capability: export has_capability
  vfio-mdev: remove some dead code
  vfio-mdev: buffer overflow in ioctl()
  vfio-mdev: return -EFAULT if copy_to_user() fails

Pull KVM fixes from Paolo Bonzini:

 - fix for module unload vs deferred jump labels (note: there might be
   other buggy modules!)

 - two NULL pointer dereferences from syzkaller

 - also syzkaller: fix emulation of fxsave/fxrstor/sgdt/sidt, problem
   made worse during this merge window, "just" kernel memory leak on
   releases

 - fix emulation of "mov ss" - somewhat serious on AMD, less so on Intel

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: fix emulation of "MOV SS, null selector"
  KVM: x86: fix NULL deref in vcpu_scan_ioapic
  KVM: eventfd: fix NULL deref irqbypass consumer
  KVM: x86: Introduce segmented_write_std
  KVM: x86: flush pending lapic jump label updates on module unload
  jump_labels: API for flushing deferred jump label updates

Pull arm64 fixes from Catalin Marinas:

 - Fix huge_ptep_set_access_flags() to return "changed" when any of the
   ptes in the contiguous range is changed, not just the last one

 - Fix the adr_l assembly macro to work in modules under KASLR

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: assembler: make adr_l work in modules under KASLR
  arm64: hugetlb: fix the wrong return value for huge_ptep_set_access_flags

Pull SCSI fixes from James Bottomley:
 "The major fix is the bfa firmware, since the latest 10Gb cards fail
  probing with the current firmware.

  The rest is a set of minor fixes: one missed Kconfig dependency
  causing randconfig failures, a missed error return on an error leg, a
  change for how multiqueue waits on a blocked device and a don't reset
  while in reset fix"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: bfa: Increase requested firmware version to 3.2.5.1
  scsi: snic: Return error code on memory allocation failure
  scsi: fnic: Avoid sending reset to firmware when another reset is in progress
  scsi: qedi: fix build, depends on UIO
  scsi: scsi-mq: Wait for .queue_rq() if necessary

Pull input updates from Dmitry Torokhov:
 "Small driver fixups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: elants_i2c - avoid divide by 0 errors on bad touchscreen data
  Input: adxl34x - make it enumerable in ACPI environment
  Input: ALPS - fix TrackStick Y axis handling for SS5 hardware
  Input: synaptics-rmi4 - fix F03 build error when serio is module
  Input: xpad - use correct product id for x360w controllers
  Input: synaptics_i2c - change msleep to usleep_range for small msecs
  Input: i8042 - add Pegatron touchpad to noloop table
  Input: joydev - remove unused linux/miscdevice.h include

Using has_capability() rather than ns_capable(), we're no longer using
this header.

Cc: Jike Song <jike.song@intel.com>
Cc: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Before the mdev enhancement type1 iommu used capable() to test the
capability of current task; in the course of mdev development a
new requirement, testing for another task other than current, was
raised.  ns_capable() was used for this purpose, however it still
tests current, the only difference is, in a specified namespace.

Fix it by using has_capability() instead, which tests the cap for
specified task in init_user_ns, the same namespace as capable().

Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Jike Song <jike.song@intel.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Pull sound fixes from Takashi Iwai:
 "This time we got a few more fixes than the previous rc's, and most of
  commits were about ASoC.

  The only significant change in the core side is the regression fix wrt
  the aux device list handling, and all the rest are driver-specific
  small / trivial fixes"

* tag 'sound-4.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Add a quirk for Plantronics BT600
  ASoC: rt5645: set sel_i2s_pre_div1 to 2
  ASoC: dpcm: Avoid putting stream state to STOP when FE stream is paused
  ASoC: Intel: Skylake: Release FW ctx in cleanup
  ASoC: Intel: bytcr-rt5640: fix settings in internal clock mode
  ASoC: fsl_ssi: set fifo watermark to more reliable value
  ASoC: nau8825: fix invalid configuration in Pre-Scalar of FLL
  ASoC: nau8825: correct the function name of register
  ASoC: Intel: Skylake: Fix to fail safely if module not available in path
  ASoC: tlv320aic3x: Mark the RESET register as volatile
  ASoC: Fix binding and probing of auxiliary components
  ASoC: wm_adsp: Don't overrun firmware file buffer when reading region data
  ASoC: Intel: bytcr_rt5640: fallback mechanism if MCLK is not enabled
  ASoC: hdmi-codec: use unsigned type to structure members with bit-field
  ASoC: topology: kfree kcontrol->private_value before freeing kcontrol
  ASoC: rsnd: don't double free kctrl
  ASoC: dwc: Fix PIO mode initialization

Pull xfs fixes from Darrick Wong:
 "As promised last week, here's some stability fixes from Christoph and
  Jan Kara:

   - fix free space request handling when low on disk space

   - remove redundant log failure error messages

   - free truncated dirty pages instead of letting them build up
     forever"

* tag 'xfs-for-linus-4.10-rc4-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: Timely free truncated dirty pages
  xfs: don't print warnings when xfs_log_force fails
  xfs: don't rely on ->total in xfs_alloc_space_available
  xfs: adjust allocation length in xfs_alloc_space_available
  xfs: fix bogus minleft manipulations
  xfs: bump up reserved blocks in xfs_alloc_set_aside

Pull remoteproc fixes from Bjorn Andersson:
 "This fixes two regressions that have been reported to be introduced in
  v4.10-rc1.

   - correct an incorrect usage of the kref api

   - revert the change to make the resource table read-only. As the
     space each vdev resource is used as virtio device config space it
     must be shared with the remote"

* tag 'rproc-v4.10-fixes' of git://github.com/andersson/remoteproc:
  Revert "remoteproc: Merge table_ptr and cached_table pointers"
  remoteproc: fix vdev reference management

Pull rpmsg fixes from Bjorn Andersson:
 "This fixes a regression introduced in v4.10-rc1 that prohibits
  multiple channels with the same name but different endpoint addresses
  to be used"

* tag 'rpmsg-v4.10-fixes' of git://github.com/andersson/remoteproc:
  rpmsg: virtio_rpmsg_bus: fix channel creation

Pull HID fixes from Jiri Kosina:

 - device descriptor length validation fix to hid-cypress driver from
   Greg

 - introduction of a short delay into i2c-hid, which is not really
   mandated by the spec, but fixes Asus Touchpads

 - Petzl USB connectable flashlight quirk from myself

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: i2c-hid: Add sleep between POWER ON and RESET
  HID: hid-cypress: validate length of report
  HID: ignore Petzl USB headlamp

Merge branch 'scsi-target-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bvanassche/linux

Pull scsi target fixes from Bart Van Assche:

 - a series of bug fixes for the XCOPY implementation from David
   Disseldorp

 - one bug fix for the ibmvscsis driver, a driver that is used for
   communication between partitions on IBM POWER systems.

* 'scsi-target-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bvanassche/linux:
  ibmvscsis: Fix srp_transfer_data fail return code
  target: support XCOPY requests without parameters
  target: check for XCOPY parameter truncation
  target: use XCOPY segment descriptor CSCD IDs
  target: check XCOPY segment descriptor CSCD IDs
  target: simplify XCOPY wwn->se_dev lookup helper
  target: return UNSUPPORTED TARGET/SEGMENT DESC TYPE CODE sense
  target: bounds check XCOPY total descriptor list length
  target: bounds check XCOPY segment descriptor list
  target: use XCOPY TOO MANY TARGET DESCRIPTORS sense
  target: add XCOPY target/segment desc sense codes

For no snapshot case, we should use ci->truncate_{seq,size}.

Fixes: 5f743e45 ("ceph: record truncate size/seq for snap data writeback")
Signed-off-by: Geng, Jichao <geng.jichao@h3c.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>

We should apply the check after getting the initial mdsmap.

Fixes: e9e427f0 ("ceph: check availability of mds cluster on mount")
Link: http://tracker.ceph.com/issues/18161Signed-off-by: Yan, Zheng <zyan@redhat.com>

Pull md fixes from Shaohua Li:
 "Basically one fix for raid5 cache which is merged in this cycle,
  others are trival fixes"

* tag 'md/4.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  md/raid5: Use correct IS_ERR() variation on pointer check
  md: cleanup mddev flag clear for takeover
  md/r5cache: fix spelling mistake on "recoverying"
  md/r5cache: assign conf->log before r5l_load_log()
  md/r5cache: simplify handling of sh->log_start in recovery
  md/raid5-cache: removes unnecessary write-through mode judgments
  md/raid10: Refactor raid10_make_request
  md/raid1: Refactor raid1_make_request

When CONFIG_RANDOMIZE_MODULE_REGION_FULL=y, the offset between loaded
modules and the core kernel may exceed 4 GB, putting symbols exported
by the core kernel out of the reach of the ordinary adrp/add instruction
pairs used to generate relative symbol references. So make the adr_l
macro emit a movz/movk sequence instead when executing in module context.

While at it, remove the pointless special case for the stack pointer.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

This is CVE-2017-2583.  On Intel this causes a failed vmentry because
SS's type is neither 3 nor 7 (even though the manual says this check is
only done for usable SS, and the dmesg splat says that SS is unusable!).
On AMD it's worse: svm.c is confused and sets CPL to 0 in the vmcb.

The fix fabricates a data segment descriptor when SS is set to a null
selector, so that CPL and SS.DPL are set correctly in the VMCS/vmcb.
Furthermore, only allow setting SS to a NULL selector if SS.RPL < 3;
this in turn ensures CPL < 3 because RPL must be equal to CPL.

Thanks to Andy Lutomirski and Willy Tarreau for help in analyzing
the bug and deciphering the manuals.
Reported-by: Xiaohan Zhang <zhangxiaohan1@huawei.com>
Fixes: 79d5b4c3
Cc: stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

has_capability() is sometimes needed by modules to test capability
for specified task other than current, so export it.

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Jike Song <jike.song@intel.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Reported by syzkaller:

    BUG: unable to handle kernel NULL pointer dereference at 00000000000001b0
    IP: _raw_spin_lock+0xc/0x30
    PGD 3e28eb067
    PUD 3f0ac6067
    PMD 0
    Oops: 0002 [#1] SMP
    CPU: 0 PID: 2431 Comm: test Tainted: G           OE   4.10.0-rc1+ #3
    Call Trace:
     ? kvm_ioapic_scan_entry+0x3e/0x110 [kvm]
     kvm_arch_vcpu_ioctl_run+0x10a8/0x15f0 [kvm]
     ? pick_next_task_fair+0xe1/0x4e0
     ? kvm_arch_vcpu_load+0xea/0x260 [kvm]
     kvm_vcpu_ioctl+0x33a/0x600 [kvm]
     ? hrtimer_try_to_cancel+0x29/0x130
     ? do_nanosleep+0x97/0xf0
     do_vfs_ioctl+0xa1/0x5d0
     ? __hrtimer_init+0x90/0x90
     ? do_nanosleep+0x5b/0xf0
     SyS_ioctl+0x79/0x90
     do_syscall_64+0x6e/0x180
     entry_SYSCALL64_slow_path+0x25/0x25
    RIP: _raw_spin_lock+0xc/0x30 RSP: ffffa43688973cc0

The syzkaller folks reported a NULL pointer dereference due to
ENABLE_CAP succeeding even without an irqchip.  The Hyper-V
synthetic interrupt controller is activated, resulting in a
wrong request to rescan the ioapic and a NULL pointer dereference.

    #include <sys/ioctl.h>
    #include <sys/mman.h>
    #include <sys/types.h>
    #include <linux/kvm.h>
    #include <pthread.h>
    #include <stddef.h>
    #include <stdint.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>

    #ifndef KVM_CAP_HYPERV_SYNIC
    #define KVM_CAP_HYPERV_SYNIC 123
    #endif

    void* thr(void* arg)
    {
	struct kvm_enable_cap cap;
	cap.flags = 0;
	cap.cap = KVM_CAP_HYPERV_SYNIC;
	ioctl((long)arg, KVM_ENABLE_CAP, &cap);
	return 0;
    }

    int main()
    {
	void *host_mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE,
			MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
	int kvmfd = open("/dev/kvm", 0);
	int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0);
	struct kvm_userspace_memory_region memreg;
	memreg.slot = 0;
	memreg.flags = 0;
	memreg.guest_phys_addr = 0;
	memreg.memory_size = 0x1000;
	memreg.userspace_addr = (unsigned long)host_mem;
	host_mem[0] = 0xf4;
	ioctl(vmfd, KVM_SET_USER_MEMORY_REGION, &memreg);
	int cpufd = ioctl(vmfd, KVM_CREATE_VCPU, 0);
	struct kvm_sregs sregs;
	ioctl(cpufd, KVM_GET_SREGS, &sregs);
	sregs.cr0 = 0;
	sregs.cr4 = 0;
	sregs.efer = 0;
	sregs.cs.selector = 0;
	sregs.cs.base = 0;
	ioctl(cpufd, KVM_SET_SREGS, &sregs);
	struct kvm_regs regs = { .rflags = 2 };
	ioctl(cpufd, KVM_SET_REGS, &regs);
	ioctl(vmfd, KVM_CREATE_IRQCHIP, 0);
	pthread_t th;
	pthread_create(&th, 0, thr, (void*)(long)cpufd);
	usleep(rand() % 10000);
	ioctl(cpufd, KVM_RUN, 0);
	pthread_join(th, 0);
	return 0;
    }

This patch fixes it by failing ENABLE_CAP if without an irqchip.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: 5c919412 (kvm/x86: Hyper-V synthetic interrupt controller)
Cc: stable@vger.kernel.org # 4.5+
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reported syzkaller:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
    IP: irq_bypass_unregister_consumer+0x9d/0xb70 [irqbypass]
    PGD 0

    Oops: 0002 [#1] SMP
    CPU: 1 PID: 125 Comm: kworker/1:1 Not tainted 4.9.0+ #1
    Workqueue: kvm-irqfd-cleanup irqfd_shutdown [kvm]
    task: ffff9bbe0dfbb900 task.stack: ffffb61802014000
    RIP: 0010:irq_bypass_unregister_consumer+0x9d/0xb70 [irqbypass]
    Call Trace:
     irqfd_shutdown+0x66/0xa0 [kvm]
     process_one_work+0x16b/0x480
     worker_thread+0x4b/0x500
     kthread+0x101/0x140
     ? process_one_work+0x480/0x480
     ? kthread_create_on_node+0x60/0x60
     ret_from_fork+0x25/0x30
    RIP: irq_bypass_unregister_consumer+0x9d/0xb70 [irqbypass] RSP: ffffb61802017e20
    CR2: 0000000000000008

The syzkaller folks reported a NULL pointer dereference that due to
unregister an consumer which fails registration before. The syzkaller
creates two VMs w/ an equal eventfd occasionally. So the second VM
fails to register an irqbypass consumer. It will make irqfd as inactive
and queue an workqueue work to shutdown irqfd and unregister the irqbypass
consumer when eventfd is closed. However, the second consumer has been
initialized though it fails registration. So the token(same as the first
VM's) is taken to unregister the consumer through the workqueue, the
consumer of the first VM is found and unregistered, then NULL deref incurred
in the path of deleting consumer from the consumers list.

This patch fixes it by making irq_bypass_register/unregister_consumer()
looks for the consumer entry based on consumer pointer itself instead of
token matching.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Cc: stable@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>