Commit 505a666e ("writeback: plug writeback in wb_writeback() and
writeback_inodes_wb()") has us holding a plug during writeback_sb_inodes,
which increases the merge rate when relatively contiguous small files
are written by the filesystem.  It helps both on flash and spindles.

For an fs_mark workload creating 4K files in parallel across 8 drives,
this commit improves performance ~9% more by unplugging before calling
cond_resched().  cond_resched() doesn't trigger an implicit unplug, so
explicitly getting the IO down to the device before scheduling reduces
latencies for anyone waiting on clean pages.

It also cuts down on how often we use kblockd to unplug, which means
less work bouncing from one workqueue to another.

Many more details about how we got here:

  https://lkml.org/lkml/2015/9/11/570



Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull virtio fixes and cleanups from Michael Tsirkin:
 "This fixes the virtio-test tool, and improves the error handling for
  virtio-ccw"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio/s390: handle failures of READ_VQ_CONF ccw
  tools/virtio: propagate V=X to kernel build
  vhost: move features to core
  tools/virtio: fix build after 4.2 changes

Pull KVM fixes from Paolo Bonzini:
 "Mostly stable material, a lot of ARM fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (22 commits)
  sched: access local runqueue directly in single_task_running
  arm/arm64: KVM: Remove 'config KVM_ARM_MAX_VCPUS'
  arm64: KVM: Remove all traces of the ThumbEE registers
  arm: KVM: Disable virtual timer even if the guest is not using it
  arm64: KVM: Disable virtual timer even if the guest is not using it
  arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources
  KVM: s390: Replace incorrect atomic_or with atomic_andnot
  arm: KVM: Fix incorrect device to IPA mapping
  arm64: KVM: Fix user access for debug registers
  KVM: vmx: fix VPID is 0000H in non-root operation
  KVM: add halt_attempted_poll to VCPU stats
  kvm: fix zero length mmio searching
  kvm: fix double free for fast mmio eventfd
  kvm: factor out core eventfd assign/deassign logic
  kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd
  KVM: make the declaration of functions within 80 characters
  KVM: arm64: add workaround for Cortex-A57 erratum #852523
  KVM: fix polling for guest halt continued even if disable it
  arm/arm64: KVM: Fix PSCI affinity info return value for non valid cores
  arm64: KVM: set {v,}TCR_EL2 RES1 bits
  ...

Pull irq updates from Thomas Gleixner:
 "This is a rather large update post rc1 due to the final steps of
  cleanups and API changes which had to wait for the preparatory patches
  to hit your tree.

   - Regression fixes for ARM GIC irqchips

   - Regression fixes and lockdep anotations for renesas irq chips

   - The leftovers of the cleanup and preparatory patches which have
     been ignored by maintainers

   - Final conversions of the newly merged users of obsolete APIs

   - Final removal of obsolete APIs

   - Final removal of ARM artifacts which had been introduced during the
     conversion of ARM to the generic interrupt code.

   - Final split of the irq_data into chip specific and common data to
     reflect the needs of hierarchical irq domains.

   - Treewide removal of the first argument of interrupt flow handlers,
     i.e. the irq number, which is not used by the majority of handlers
     and simple to retrieve from the other argument the irq descriptor.

   - A few comment updates and build warning fixes"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  arm64: Remove ununsed set_irq_flags
  ARM: Remove ununsed set_irq_flags
  sh: Kill off set_irq_flags usage
  irqchip: Kill off set_irq_flags usage
  gpu/drm: Kill off set_irq_flags usage
  genirq: Remove irq argument from irq flow handlers
  genirq: Move field 'msi_desc' from irq_data into irq_common_data
  genirq: Move field 'affinity' from irq_data into irq_common_data
  genirq: Move field 'handler_data' from irq_data into irq_common_data
  genirq: Move field 'node' from irq_data into irq_common_data
  irqchip/gic-v3: Use IRQD_FORWARDED_TO_VCPU flag
  irqchip/gic: Use IRQD_FORWARDED_TO_VCPU flag
  genirq: Provide IRQD_FORWARDED_TO_VCPU status flag
  genirq: Simplify irq_data_to_desc()
  genirq: Remove __irq_set_handler_locked()
  pinctrl/pistachio: Use irq_set_handler_locked
  gpio: vf610: Use irq_set_handler_locked
  powerpc/mpc8xx: Use irq_set_handler_locked()
  powerpc/ipic: Use irq_set_handler_locked()
  powerpc/cpm2: Use irq_set_handler_locked()
  ...

Pull x86 fix from Thomas Gleixner:
 "A single regression fix for the x86 dma allocator which got wreckaged
  in the merge window"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pci/dma: Fix gfp flags for coherent DMA memory allocation

Pull powerpc fixes from Michael Ellerman:

 - Fix 32-bit TCE table init in kdump kernel from Nish

 - Fix kdump with non-power-of-2 crashkernel= from Nish

 - Abort cxl_pci_enable_device_hook() if PCI channel is offline from
   Andrew

 - Fix to release DRC when configure_connector() fails from Bharata

 - Wire up sys_userfaultfd()

 - Fix race condition in tearing down MSI interrupts from Paul

 - Fix unbalanced pci_dev_get() in cxl_probe() from Daniel

 - Fix cxl build failure due to -Wunused-variable gcc behaviour change
   from Ian

 - Tell the toolchain to use ABI v2 when building an LE boot wrapper
   from Benh

 - Fix THP to recompute hash value after a failed update from Aneesh

 - 32-bit memcpy/memset: only use dcbz once cache is enabled from
   Christophe

* tag 'powerpc-4.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc32: memset: only use dcbz once cache is enabled
  powerpc32: memcpy: only use dcbz once cache is enabled
  powerpc/mm: Recompute hash value after a failed update
  powerpc/boot: Specify ABI v2 when building an LE boot wrapper
  cxl: Fix build failure due to -Wunused-variable behaviour change
  cxl: Fix unbalanced pci_dev_get in cxl_probe
  powerpc/MSI: Fix race condition in tearing down MSI interrupts
  powerpc: Wire up sys_userfaultfd()
  powerpc/pseries: Release DRC when configure_connector fails
  cxl: abort cxl_pci_enable_device_hook() if PCI channel is offline
  powerpc/powernv/pci-ioda: fix kdump with non-power-of-2 crashkernel=
  powerpc/powernv/pci-ioda: fix 32-bit TCE table init in kdump kernel

Commit 2ee507c4 ("sched: Add function single_task_running to let a task
check if it is the only task running on a cpu") referenced the current
runqueue with the smp_processor_id.  When CONFIG_DEBUG_PREEMPT is enabled,
that is only allowed if preemption is disabled or the currrent task is
bound to the local cpu (e.g. kernel worker).

With commit f7819512 ("kvm: add halt_poll_ns module parameter") KVM
calls single_task_running. If CONFIG_DEBUG_PREEMPT is enabled that
generates a lot of kernel messages.

To avoid adding preemption in that cases, as it would limit the usefulness,
we change single_task_running to access directly the cpu local runqueue.

Cc: Tim Chen <tim.c.chen@linux.intel.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Fixes: 2ee507c4
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'platform-drivers-x86-v4.3-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86

Pull x86 platform driver fixes from Darren Hart:
 "Fix an issue introduced by the previous major toshiba rework.  Add a
  quirk.  Workaround a few platform specific firmware items.  One
  cleanup to wmi I inadvertently dropped from a previous pull request.

  Details:

  hp-wmi:
   - limit hotkey enable

  toshiba_acpi:
   - Fix hotkeys registration on some toshiba models
   - Fix USB Sleep and Music always disabled

  wmi:
   - Remove private %pUL implementation

  asus-nb-wmi:
   - Add wapf=4 quirk for X456UA/X456UF"

* tag 'platform-drivers-x86-v4.3-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
  hp-wmi: limit hotkey enable
  toshiba_acpi: Fix hotkeys registration on some toshiba models
  toshiba_acpi: Fix USB Sleep and Music always disabled
  wmi: Remove private %pUL implementation
  asus-nb-wmi: Add wapf=4 quirk for X456UA/X456UF

Merge misc fixes from ANdrew Morton:
 "8 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  revert "mm: make sure all file VMAs have ->vm_ops set"
  MAINTAINERS: update LTP mailing list
  userfaultfd: add missing mmput() in error path
  lib/string_helpers.c: fix infinite loop in string_get_size()
  alpha: lib: export __delay
  alpha: io: define ioremap_uc
  kasan: fix last shadow judgement in memory_is_poisoned_16()
  zram: fix possible use after free in zcomp_create()

Revert commit 6dc296e7 "mm: make sure all file VMAs have ->vm_ops
set".

Will Deacon reports that it "causes some mmap regressions in LTP, which
appears to use a MAP_PRIVATE mmap of /dev/zero as a way to get anonymous
pages in some of its tests (specifically mmap10 [1])".

William Shuman reports Oracle crashes.

So revert the patch while we work out what to do.

Reported-by: William Shuman <wshuman3@gmail.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[akpm@linux-foundation.org: Wanlong Gao has moved]
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>
Cc: Alexey Kodanev <alexey.kodanev@oracle.com>
Cc: Wanlong Gao <wanlong.gao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This fixes a memleak if anon_inode_getfile() fails in userfaultfd().

Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Some string_get_size() calls (e.g.:
 string_get_size(1, 512, STRING_UNITS_10, ..., ...)
 string_get_size(15, 64, STRING_UNITS_10, ..., ...)
) result in an infinite loop. The problem is that if size is equal to
divisor[units]/blk_size and is smaller than divisor[units] we'll end
up with size == 0 when we start doing sf_cap calculations:

For string_get_size(1, 512, STRING_UNITS_10, ..., ...) case:
   ...
   remainder = do_div(size, divisor[units]); -> size is 0, remainder is 1
   remainder *= blk_size; -> remainder is 512
   ...
   size *= blk_size; -> size is still 0
   size += remainder / divisor[units]; -> size is still 0

The caller causing the issue is sd_read_capacity(), the problem was
noticed on Hyper-V, such weird size was reported by host when scanning
collides with device removal.  This is probably a separate issue worth
fixing, this patch is intended to prevent the library routine from
infinite looping.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: James Bottomley <JBottomley@Odin.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

__delay was not exported as a result while building with allmodconfig we
were getting build error of undefined symbol.  __delay is being used by:
drivers/net/phy/mdio-octeon.c

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ioremap_uc was not defined and as a result while building with
allmodconfig were getting build error of: implicit declaration of
function 'ioremap_uc'.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The shadow which correspond 16 bytes memory may span 2 or 3 bytes.  If
the memory is aligned on 8, then the shadow takes only 2 bytes.  So we
check "shadow_first_bytes" is enough, and need not to call
"memory_is_poisoned_1(addr + 15);".  But the code "if
(likely(!last_byte))" is wrong judgement.

e.g.  addr=0, so last_byte = 15 & KASAN_SHADOW_MASK = 7, then the code
will continue to call "memory_is_poisoned_1(addr + 15);"

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.cz>
Cc: <zhongjiang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zcomp_create() verifies the success of zcomp_strm_{multi,single}_create()
through comp->stream, which can potentially be pointing to memory that
was freed if these functions returned an error.

While at it, replace a 'ERR_PTR(-ENOMEM)' by a more generic
'ERR_PTR(error)' as in the future zcomp_strm_{multi,siggle}_create()
could return other error codes.  Function documentation updated
accordingly.

Fixes: beca3ec7 ("zram: add multi stream functionality")
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@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>

Do not write initialize magic on systems that do not have
feature query 0xb. Fixes Bug #82451.

Redefine FEATURE_QUERY to align with 0xb and FEATURE2 with 0xd
for code clearity.

Add a new test function, hp_wmi_bios_2008_later() & simplify
hp_wmi_bios_2009_later(), which fixes a bug in cases where
an improper value is returned. Probably also fixes Bug #69131.

Add missing __init tag.

Signed-off-by: Kyle Evans <kvans32@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

Pull Ceph fixes from Sage Weil:
 "These are both fixes to the new and improved keepalive2 behavior"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  libceph: advertise support for keepalive2
  libceph: don't access invalid memory in keepalive2 path

Pull power supply fixes from Sebastian Reichel:
 "twl4030-charger fixes"

* tag 'for-v4.3-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply:
  twl4030_charger: fix another compile error
  Revert "twl4030_charger: correctly handle -EPROBE_DEFER from devm_usb_get_phy_by_node"

Pull arm64 fixes from Will Deacon:
 "This addresses some problems with filesystem writeback due to the
  recently merged hardware DBM patches, which caused us to treat some
  read-only pages as dirty.

  There are also some other, less significant fixes that are described
  in the summary below:

  A mixture of fixes for regressions introduced during the merge window,
  some longer standing problems that we spotted and a couple of hardware
  errata.  The main changes are:

   - Fix fallout from the h/w DBM patches, causing filesystem writeback
     issues on both v8 and v8.1 CPUs

   - Workaround for Cortex-A53 erratum #843419 in the module loader

   - Fix for long-standing issue with compat big-endian signal handlers
     using the saved floating point state"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: errata: add module build workaround for erratum #843419
  arm64: compat: fix vfp save/restore across signal handlers in big-endian
  arm64: cpu hotplug: ensure we mask out CPU_TASKS_FROZEN in notifiers
  arm64: head.S: initialise mdcr_el2 in el2_setup
  arm64: enable generic idle loop
  arm64: pgtable: use a single bit for PTE_WRITE regardless of DBM
  arm64: Fix pte_modify() to preserve the hardware dirty information
  arm64: Fix the pte_hw_dirty() check when AF/DBM is enabled
  arm64: dma-mapping: check whether cma area is initialized or not

Pull x86 fixes from Ingo Molnar:
 - misc fixes all around the map
 - block non-root vm86(old) if mmap_min_addr != 0
 - two small debuggability improvements
 - removal of obsolete paravirt op

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform: Fix Geode LX timekeeping in the generic x86 build
  x86/apic: Serialize LVTT and TSC_DEADLINE writes
  x86/ioapic: Force affinity setting in setup_ioapic_dest()
  x86/paravirt: Remove the unused pv_time_ops::get_tsc_khz method
  x86/ldt: Fix small LDT allocation for Xen
  x86/vm86: Fix the misleading CONFIG_VM86 Kconfig help text
  x86/cpu: Print family/model/stepping in hex
  x86/vm86: Block non-root vm86(old) if mmap_min_addr != 0
  x86/alternatives: Make optimize_nops() interrupt safe and synced
  x86/mm/srat: Print non-volatile flag in SRAT
  x86/cpufeatures: Enable cpuid for Intel SHA extensions

Pull timer fixes from Ingo Molnar:
 "A fix for an abs()/abs64() bug that caused too slow NTP convergence on
  32-bit kernels, plus a removal of an obsolete clockevents driver
  facility after all users got converted during the merge window"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clockevents: Remove unused set_mode() callback
  time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of abs64()

Pull scheduler fixes from Ingo Molnar:
 "A migrate_tasks() locking fix, and a late-coming nohz change plus a
  nohz debug check"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: 'Annotate' migrate_tasks()
  nohz: Assert existing housekeepers when nohz full enabled
  nohz: Affine unpinned timers to housekeepers

Pull perf fixes from Ingo MOlnar:
 "Mostly tooling fixes, but also two x86 PMU driver fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tests: Fix software clock events test setting maps
  perf tests: Fix task exit test setting maps
  perf evlist: Fix create_syswide_maps() not propagating maps
  perf evlist: Fix add() not propagating maps
  perf evlist: Factor out a function to propagate maps for a single evsel
  perf evlist: Make create_maps() use set_maps()
  perf evlist: Make set_maps() more resilient
  perf evsel: Add own_cpus member
  perf evlist: Fix missing thread_map__put in propagate_maps()
  perf evlist: Fix splice_list_tail() not setting evlist
  perf evlist: Add has_user_cpus member
  perf evlist: Remove redundant validation from propagate_maps()
  perf evlist: Simplify set_maps() logic
  perf evlist: Simplify propagate_maps() logic
  perf top: Fix segfault pressing -> with no hist entries
  perf header: Fixup reading of HEADER_NRCPUS feature
  perf/x86/intel: Fix constraint access
  perf/x86/intel/bts: Set event->hw.itrace_started in pmu::start to match the new logic
  perf tools: Fix use of wrong event when processing exit events
  perf tools: Fix parse_events_add_pmu caller

We are the client, but advertise keepalive2 anyway - for consistency,
if nothing else.  In the future the server might want to know whether
its clients support keepalive2.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>

This

    struct ceph_timespec ceph_ts;
    ...
    con_out_kvec_add(con, sizeof(ceph_ts), &ceph_ts);

wraps ceph_ts into a kvec and adds it to con->out_kvec array, yet
ceph_ts becomes invalid on return from prepare_write_keepalive().  As
a result, we send out bogus keepalive2 stamps.  Fix this by encoding
into a ceph_timespec member, similar to how acks are read and written.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>

Pull locking fixes from Ingo Molnar:
 "Spinlock performance regression fix, plus documentation fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/static_keys: Fix up the static keys documentation
  locking/qspinlock/x86: Only emit the test-and-set fallback when building guest support
  locking/qspinlock/x86: Fix performance regression under unaccelerated VMs
  locking/static_keys: Fix a silly typo

Pull RCU fix from Ingo Molnar:
 "Fix a false positive warning"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  security/device_cgroup: Fix RCU_LOCKDEP_WARN() condition

Merge tag 'kvm-arm-for-4.3-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-master

Second set of KVM/ARM changes for 4.3-rc2

- Workaround for a Cortex-A57 erratum
- Bug fix for the debugging infrastructure
- Fix for 32bit guests with more than 4GB of address space
  on a 32bit host
- A number of fixes for the (unusual) case when we don't use
  the in-kernel GIC emulation
- Removal of ThumbEE handling on arm64, since these have been
  dropped from the architecture before anyone actually ever
  built a CPU
- Remove the KVM_ARM_MAX_VCPUS limitation which has become
  fairly pointless

Commit 6894258e reversed the order of gfp_flags adjustment in
dma_alloc_attrs() for x86 [arch/x86/kernel/pci-dma.c] As a result,
relevant flags set by dma_alloc_coherent_gfp_flags() are just
discarded and cause coherent DMA memory allocation failure on some
devices.

Fixes: 6894258e ("dma-mapping: consolidate dma_{alloc,free}_{attrs,coherent}")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20150914073834.GA13077@xzibit.linux.bs1.fc.nec.co.jp


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

This patch removes config option of KVM_ARM_MAX_VCPUS,
and like other ARCHs, just choose the maximum allowed
value from hardware, and follows the reasons:

1) from distribution view, the option has to be
defined as the max allowed value because it need to
meet all kinds of virtulization applications and
need to support most of SoCs;

2) using a bigger value doesn't introduce extra memory
consumption, and the help text in Kconfig isn't accurate
because kvm_vpu structure isn't allocated until request
of creating VCPU is sent from QEMU;

3) the main effect is that the field of vcpus[] in 'struct kvm'
becomes a bit bigger(sizeof(void *) per vcpu) and need more cache
lines to hold the structure, but 'struct kvm' is one generic struct,
and it has worked well on other ARCHs already in this way. Also,
the world switch frequecy is often low, for example, it is ~2000
when running kernel building load in VM from APM xgene KVM host,
so the effect is very small, and the difference can't be observed
in my test at all.

Cc: Dann Frazier <dann.frazier@canonical.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Although the ThumbEE registers and traps were present in earlier
versions of the v8 architecture, it was retrospectively removed and so
we can do the same.

Whilst this breaks migrating a guest started on a previous version of
the kernel, it is much better to kill these (non existent) registers
as soon as possible.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[maz: added commend about migration]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When running a guest with the architected timer disabled (with QEMU and
the kernel_irqchip=off option, for example), it is important to make
sure the timer gets turned off. Otherwise, the guest may try to
enable it anyway, leading to a screaming HW interrupt.

The fix is to unconditionally turn off the virtual timer on guest
exit.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

When running a guest with the architected timer disabled (with QEMU and
the kernel_irqchip=off option, for example), it is important to make
sure the timer gets turned off. Otherwise, the guest may try to
enable it anyway, leading to a screaming HW interrupt.

The fix is to unconditionally turn off the virtual timer on guest
exit.

Cc: stable@vger.kernel.org
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Cortex-A53 processors <= r0p4 are affected by erratum #843419 which can
lead to a memory access using an incorrect address in certain sequences
headed by an ADRP instruction.

There is a linker fix to generate veneers for ADRP instructions, but
this doesn't work for kernel modules which are built as unlinked ELF
objects.

This patch adds a new config option for the erratum which, when enabled,
builds kernel modules with the mcmodel=large flag. This uses absolute
addressing for all kernel symbols, thereby removing the use of ADRP as
a PC-relative form of addressing. The ADRP relocs are removed from the
module loader so that we fail to load any potentially affected modules.

Cc: <stable@vger.kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When saving/restoring the VFP registers from a compat (AArch32)
signal frame, we rely on the compat registers forming a prefix of the
native register file and therefore make use of copy_{to,from}_user to
transfer between the native fpsimd_state and the compat_vfp_sigframe.

Unfortunately, this doesn't work so well in a big-endian environment.
Our fpsimd save/restore code operates directly on 128-bit quantities
(Q registers) whereas the compat_vfp_sigframe represents the registers
as an array of 64-bit (D) registers. The architecture packs the compat D
registers into the Q registers, with the least significant bytes holding
the lower register. Consequently, we need to swap the 64-bit halves when
converting between these two representations on a big-endian machine.

This patch replaces the __copy_{to,from}_user invocations in our
compat VFP signal handling code with explicit __put_user loops that
operate on 64-bit values and swap them accordingly.

Cc: <stable@vger.kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

We have a couple of CPU hotplug notifiers for resetting the CPU debug
state to a sane value when a CPU comes online.

This patch ensures that we mask out CPU_TASKS_FROZEN so that we don't
miss any online events occuring due to suspend/resume.

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

memset() uses instruction dcbz to speed up clearing by not wasting time
loading cache line with data that will be overwritten.
Some platform like mpc52xx do no have cache active at startup and
can therefore not use memset(). Allthough no part of the code
explicitly uses memset(), GCC may make calls to it.

This patch modifies memset() such that at startup, memset()
unconditionally skip the optimised bloc that uses dcbz instruction.

Once the initial MMU is set up, in machine_init() we patch memset()
by replacing this inconditional jump by a NOP

Tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

memcpy() uses instruction dcbz to speed up copy by not wasting time
loading cache line with data that will be overwritten.
Some platform like mpc52xx do no have cache active at startup and
can therefore not use memcpy(). Allthough no part of the code
explicitly uses memcpy(), GCC makes calls to it.

This patch modifies memcpy() such that at startup, memcpy()
unconditionally jumps to generic_memcpy() which doesn't use
the dcbz instruction.

Once the initial MMU is set up, in machine_init() we patch memcpy()
by replacing this inconditional jump by a NOP

Reported-by: Michal Sojka <sojkam1@fel.cvut.cz>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>