The CPU controller hasn't kept up with the various changes in the whole
cgroup initialization / destruction sequence, and commit:

  2e91fa7f ("cgroup: keep zombies associated with their original cgroups")

caused it to explode.

The reason for this is that zombies do not inhibit css_offline() from
being called, but do stall css_released(). Now we tear down the cfs_rq
structures on css_offline() but zombies can run after that, leading to
use-after-free issues.

The solution is to move the tear-down to css_released(), which
guarantees nobody (including no zombies) is still using our cgroup.

Furthermore, a few simple cleanups are possible too. There doesn't
appear to be any point to us using css_online() (anymore?) so fold that
in css_alloc().

And since cgroup code guarantees an RCU grace period between
css_released() and css_free() we can forgo using call_rcu() and free the
stuff immediately.
Suggested-by: Tejun Heo <tj@kernel.org>
Reported-by: Kazuki Yamaguchi <k@rhe.jp>
Reported-by: Niklas Cassel <niklas.cassel@axis.com>
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2e91fa7f ("cgroup: keep zombies associated with their original cgroups")
Link: http://lkml.kernel.org/r/20160316152245.GY6344@twins.programming.kicks-ass.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull cpu hotplug updates from Thomas Gleixner:
 "This is the first part of the ongoing cpu hotplug rework:

   - Initial implementation of the state machine

   - Runs all online and prepare down callbacks on the plugged cpu and
     not on some random processor

   - Replaces busy loop waiting with completions

   - Adds tracepoints so the states can be followed"

More detailed commentary on this work from an earlier email:
 "What's wrong with the current cpu hotplug infrastructure?

   - Asymmetry

     The hotplug notifier mechanism is asymmetric versus the bringup and
     teardown.  This is mostly caused by the notifier mechanism.

   - Largely undocumented dependencies

     While some notifiers use explicitely defined notifier priorities,
     we have quite some notifiers which use numerical priorities to
     express dependencies without any documentation why.

   - Control processor driven

     Most of the bringup/teardown of a cpu is driven by a control
     processor.  While it is understandable, that preperatory steps,
     like idle thread creation, memory allocation for and initialization
     of essential facilities needs to be done before a cpu can boot,
     there is no reason why everything else must run on a control
     processor.  Before this patch series, bringup looks like this:

       Control CPU                     Booting CPU

       do preparatory steps
       kick cpu into life

                                       do low level init

       sync with booting cpu           sync with control cpu

       bring the rest up

   - All or nothing approach

     There is no way to do partial bringups.  That's something which is
     really desired because we waste e.g.  at boot substantial amount of
     time just busy waiting that the cpu comes to life.  That's stupid
     as we could very well do preparatory steps and the initial IPI for
     other cpus and then go back and do the necessary low level
     synchronization with the freshly booted cpu.

   - Minimal debuggability

     Due to the notifier based design, it's impossible to switch between
     two stages of the bringup/teardown back and forth in order to test
     the correctness.  So in many hotplug notifiers the cancel
     mechanisms are either not existant or completely untested.

   - Notifier [un]registering is tedious

     To [un]register notifiers we need to protect against hotplug at
     every callsite.  There is no mechanism that bringup/teardown
     callbacks are issued on the online cpus, so every caller needs to
     do it itself.  That also includes error rollback.

  What's the new design?

     The base of the new design is a symmetric state machine, where both
     the control processor and the booting/dying cpu execute a well
     defined set of states.  Each state is symmetric in the end, except
     for some well defined exceptions, and the bringup/teardown can be
     stopped and reversed at almost all states.

     So the bringup of a cpu will look like this in the future:

       Control CPU                     Booting CPU

       do preparatory steps
       kick cpu into life

                                       do low level init

       sync with booting cpu           sync with control cpu

                                       bring itself up

     The synchronization step does not require the control cpu to wait.
     That mechanism can be done asynchronously via a worker or some
     other mechanism.

     The teardown can be made very similar, so that the dying cpu cleans
     up and brings itself down.  Cleanups which need to be done after
     the cpu is gone, can be scheduled asynchronously as well.

  There is a long way to this, as we need to refactor the notion when a
  cpu is available.  Today we set the cpu online right after it comes
  out of the low level bringup, which is not really correct.

  The proper mechanism is to set it to available, i.e. cpu local
  threads, like softirqd, hotplug thread etc. can be scheduled on that
  cpu, and once it finished all booting steps, it's set to online, so
  general workloads can be scheduled on it.  The reverse happens on
  teardown.  First thing to do is to forbid scheduling of general
  workloads, then teardown all the per cpu resources and finally shut it
  off completely.

  This patch series implements the basic infrastructure for this at the
  core level.  This includes the following:

   - Basic state machine implementation with well defined states, so
     ordering and prioritization can be expressed.

   - Interfaces to [un]register state callbacks

     This invokes the bringup/teardown callback on all online cpus with
     the proper protection in place and [un]installs the callbacks in
     the state machine array.

     For callbacks which have no particular ordering requirement we have
     a dynamic state space, so that drivers don't have to register an
     explicit hotplug state.

     If a callback fails, the code automatically does a rollback to the
     previous state.

   - Sysfs interface to drive the state machine to a particular step.

     This is only partially functional today.  Full functionality and
     therefor testability will be achieved once we converted all
     existing hotplug notifiers over to the new scheme.

   - Run all CPU_ONLINE/DOWN_PREPARE notifiers on the booting/dying
     processor:

       Control CPU                     Booting CPU

       do preparatory steps
       kick cpu into life

                                       do low level init

       sync with booting cpu           sync with control cpu
       wait for boot
                                       bring itself up

                                       Signal completion to control cpu

     In a previous step of this work we've done a full tree mechanical
     conversion of all hotplug notifiers to the new scheme.  The balance
     is a net removal of about 4000 lines of code.

     This is not included in this series, as we decided to take a
     different approach.  Instead of mechanically converting everything
     over, we will do a proper overhaul of the usage sites one by one so
     they nicely fit into the symmetric callback scheme.

     I decided to do that after I looked at the ugliness of some of the
     converted sites and figured out that their hotplug mechanism is
     completely buggered anyway.  So there is no point to do a
     mechanical conversion first as we need to go through the usage
     sites one by one again in order to achieve a full symmetric and
     testable behaviour"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  cpu/hotplug: Document states better
  cpu/hotplug: Fix smpboot thread ordering
  cpu/hotplug: Remove redundant state check
  cpu/hotplug: Plug death reporting race
  rcu: Make CPU_DYING_IDLE an explicit call
  cpu/hotplug: Make wait for dead cpu completion based
  cpu/hotplug: Let upcoming cpu bring itself fully up
  arch/hotplug: Call into idle with a proper state
  cpu/hotplug: Move online calls to hotplugged cpu
  cpu/hotplug: Create hotplug threads
  cpu/hotplug: Split out the state walk into functions
  cpu/hotplug: Unpark smpboot threads from the state machine
  cpu/hotplug: Move scheduler cpu_online notifier to hotplug core
  cpu/hotplug: Implement setup/removal interface
  cpu/hotplug: Make target state writeable
  cpu/hotplug: Add sysfs state interface
  cpu/hotplug: Hand in target state to _cpu_up/down
  cpu/hotplug: Convert the hotplugged cpu work to a state machine
  cpu/hotplug: Convert to a state machine for the control processor
  cpu/hotplug: Add tracepoints
  ...

Pull irq updates from Thomas Gleixner:
 "The 4.6 pile of irq updates contains:

   - Support for IPI irqdomains to support proper integration of IPIs to
     and from coprocessors.  The first user of this new facility is
     MIPS.  The relevant MIPS patches come with the core to avoid merge
     ordering issues and have been acked by Ralf.

   - A new command line option to set the default interrupt affinity
     mask at boot time.

   - Support for some more new ARM and MIPS interrupt controllers:
     tango, alpine-msix and bcm6345-l1

   - Two small cleanups for x86/apic which we merged into irq/core to
     avoid yet another branch in x86 with two tiny commits.

   - The usual set of updates, cleanups in drivers/irqchip.  Mostly in
     the area of ARM-GIC, arada-37-xp and atmel chips.  Nothing
     outstanding here"

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (56 commits)
  irqchip/irq-alpine-msi: Release the correct domain on error
  irqchip/mxs: Fix error check of of_io_request_and_map()
  irqchip/sunxi-nmi: Fix error check of of_io_request_and_map()
  genirq: Export IRQ functions for module use
  irqchip/gic/realview: Support more RealView DCC variants
  Documentation/bindings: Document the Alpine MSIX driver
  irqchip: Add the Alpine MSIX interrupt controller
  irqchip/gic-v3: Always return IRQ_SET_MASK_OK_DONE in gic_set_affinity
  irqchip/gic-v3-its: Mark its_init() and its children as __init
  irqchip/gic-v3: Remove gic_root_node variable from the ITS code
  irqchip/gic-v3: ACPI: Add redistributor support via GICC structures
  irqchip/gic-v3: Add ACPI support for GICv3/4 initialization
  irqchip/gic-v3: Refactor gic_of_init() for GICv3 driver
  x86/apic: Deinline _flat_send_IPI_mask, save ~150 bytes
  x86/apic: Deinline __default_send_IPI_*, save ~200 bytes
  dt-bindings: interrupt-controller: Add SoC-specific compatible string to Marvell ODMI
  irqchip/mips-gic: Add new DT property to reserve IPIs
  MIPS: Delete smp-gic.c
  MIPS: Make smp CMP, CPS and MT use the new generic IPI functions
  MIPS: Add generic SMP IPI support
  ...

Pull timer updates from Thomas Gleixner:
 "The timer department delivers this time:

   - Support for cross clock domain timestamps in the core code plus a
     first user.  That allows more precise timestamping for PTP and
     later for audio and other peripherals.

     The ptp/e1000e patches have been acked by the relevant maintainers
     and are carried in the timer tree to avoid merge ordering issues.

   - Support for unregistering the current clocksource watchdog.  That
     lifts a limitation for switching clocksources which has been there
     from day 1

   - The usual pile of fixes and updates to the core and the drivers.
     Nothing outstanding and exciting"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  time/timekeeping: Work around false positive GCC warning
  e1000e: Adds hardware supported cross timestamp on e1000e nic
  ptp: Add PTP_SYS_OFFSET_PRECISE for driver crosstimestamping
  x86/tsc: Always Running Timer (ART) correlated clocksource
  hrtimer: Revert CLOCK_MONOTONIC_RAW support
  time: Add history to cross timestamp interface supporting slower devices
  time: Add driver cross timestamp interface for higher precision time synchronization
  time: Remove duplicated code in ktime_get_raw_and_real()
  time: Add timekeeping snapshot code capturing system time and counter
  time: Add cycles to nanoseconds translation
  jiffies: Use CLOCKSOURCE_MASK instead of constant
  clocksource: Introduce clocksource_freq2mult()
  clockevents/drivers/exynos_mct: Implement ->set_state_oneshot_stopped()
  clockevents/drivers/arm_global_timer: Implement ->set_state_oneshot_stopped()
  clockevents/drivers/arm_arch_timer: Implement ->set_state_oneshot_stopped()
  clocksource/drivers/arm_global_timer: Register delay timer
  clocksource/drivers/lpc32xx: Support timer-based ARM delay
  clocksource/drivers/lpc32xx: Support periodic mode
  clocksource/drivers/lpc32xx: Don't use the prescaler counter for clockevents
  clocksource/drivers/rockchip: Add err handle for rk_timer_init
  ...

Pull RCU updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Miscellaneous fixes, cleanups, restructuring.

   - RCU torture-test updates"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Export rcu_gp_is_normal()
  rcu: Remove rcu_user_hooks_switch
  rcu: Catch up rcu_report_qs_rdp() comment with reality
  rcu: Document unique-name limitation for DEFINE_STATIC_SRCU()
  rcu: Make rcu/tiny_plugin.h explicitly non-modular
  irq: Privatize irq_common_data::state_use_accessors
  RCU: Privatize rcu_node::lock
  sparse: Add __private to privatize members of structs
  rcu: Remove useless rcu_data_p when !PREEMPT_RCU
  rcutorture: Correct no-expedite console messages
  rcu: Set rdp->gpwrap when CPU is idle
  rcu: Stop treating in-kernel CPU-bound workloads as errors
  rcu: Update rcu_report_qs_rsp() comment
  rcu: Assign false instead of 0 for ->core_needs_qs
  rcutorture: Check for self-detected stalls
  rcutorture: Don't keep empty console.log.diags files
  rcutorture: Add checks for rcutorture writer starvation

Pull x86 timer update from Ingo Molnar:
 "A single simplification of the x86 TSC code"

* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tsc: Use topology functions

Pull x86 core platform updates from Ingo Molnar:
 "Intel Quark and Geode SoC platform updates"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/intel/quark: Drop IMR lock bit support
  x86/platform/intel/mid: Remove dead code
  x86/platform: Make platform/geode/net5501.c explicitly non-modular
  x86/platform: Make platform/geode/alix.c explicitly non-modular
  x86/platform: Make platform/geode/geos.c explicitly non-modular
  x86/platform: Make platform/intel-quark/imr_selftest.c explicitly non-modular
  x86/platform: Make platform/intel-quark/imr.c explicitly non-modular

Pull x86 mm updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Enable full ASLR randomization for 32-bit programs (Hector
     Marco-Gisbert)

   - Add initial minimal INVPCI support, to flush global mappings (Andy
     Lutomirski)

   - Add KASAN enhancements (Andrey Ryabinin)

   - Fix mmiotrace for huge pages (Karol Herbst)

   - ... misc cleanups and small enhancements"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/32: Enable full randomization on i386 and X86_32
  x86/mm/kmmio: Fix mmiotrace for hugepages
  x86/mm: Avoid premature success when changing page attributes
  x86/mm/ptdump: Remove paravirt_enabled()
  x86/mm: Fix INVPCID asm constraint
  x86/dmi: Switch dmi_remap() from ioremap() [uncached] to ioremap_cache()
  x86/mm: If INVPCID is available, use it to flush global mappings
  x86/mm: Add a 'noinvpcid' boot option to turn off INVPCID
  x86/mm: Add INVPCID helpers
  x86/kasan: Write protect kasan zero shadow
  x86/kasan: Clear kasan_zero_page after TLB flush
  x86/mm/numa: Check for failures in numa_clear_kernel_node_hotplug()
  x86/mm/numa: Clean up numa_clear_kernel_node_hotplug()
  x86/mm: Make kmap_prot into a #define
  x86/mm/32: Set NX in __supported_pte_mask before enabling paging
  x86/mm: Streamline and restore probe_memory_block_size()

Pull x86 microcode updates from Ingo Molnar:
 "The biggest change in this cycle was the separation of the microcode
  loading mechanism from the initrd code plus the support of built-in
  microcode images.

  There were also lots cleanups and general restructuring (by Borislav
  Petkov)"

* 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86/microcode/intel: Drop orig_sum from ext signature checksum
  x86/microcode/intel: Improve microcode sanity-checking error messages
  x86/microcode/intel: Merge two consecutive if-statements
  x86/microcode/intel: Get rid of DWSIZE
  x86/microcode/intel: Change checksum variables to u32
  x86/microcode: Use kmemdup() rather than duplicating its implementation
  x86/microcode: Remove unnecessary paravirt_enabled check
  x86/microcode: Document builtin microcode loading method
  x86/microcode/AMD: Issue microcode updated message later
  x86/microcode/intel: Cleanup get_matching_model_microcode()
  x86/microcode/intel: Remove unused arg of get_matching_model_microcode()
  x86/microcode/intel: Rename mc_saved_in_initrd
  x86/microcode/intel: Use *wrmsrl variants
  x86/microcode/intel: Cleanup apply_microcode_intel()
  x86/microcode/intel: Move the BUG_ON up and turn it into WARN_ON
  x86/microcode/intel: Rename mc_intel variable to mc
  x86/microcode/intel: Rename mc_saved_count to num_saved
  x86/microcode/intel: Rename local variables of type struct mc_saved_data
  x86/microcode/AMD: Drop redundant printk prefix
  x86/microcode: Issue update message only once
  ...

Pull x86 fpu updates from Ingo Molnar:
 "The biggest change in terms of impact is the changing of the FPU
  context switch model to 'eagerfpu' for all CPU types, via: commit
  58122bf1: "x86/fpu: Default eagerfpu=on on all CPUs"

  This makes all FPU saves and restores synchronous and makes the FPU
  code a lot more obvious to read.  In the next cycle, if this change is
  problem free, we'll remove the old lazy FPU restore code altogether.

  This change flushed out some old bugs, which should all be fixed by
  now, BYMMV"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu: Default eagerfpu=on on all CPUs
  x86/fpu: Speed up lazy FPU restores slightly
  x86/fpu: Fold fpu_copy() into fpu__copy()
  x86/fpu: Fix FNSAVE usage in eagerfpu mode
  x86/fpu: Fix math emulation in eager fpu mode

Pull x86 build update from Ingo Molnar:
 "A single adjustment of a defconfig value"

* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/defconfigs/32: Set CONFIG_FRAME_WARN to the Kconfig default

Pull x86 boot updates from Ingo Molnar:
 "Early command line options parsing enhancements from Dave Hansen, plus
  minor cleanups and enhancements"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Remove unused 'is_big_kernel' variable
  x86/boot: Use proper array element type in memset() size calculation
  x86/boot: Pass in size to early cmdline parsing
  x86/boot: Simplify early command line parsing
  x86/boot: Fix early command-line parsing when partial word matches
  x86/boot: Fix early command-line parsing when matching at end
  x86/boot: Simplify kernel load address alignment check
  x86/boot: Micro-optimize reset_early_page_tables()

Pull x86 asm updates from Ingo Molnar:
 "This is another big update. Main changes are:

   - lots of x86 system call (and other traps/exceptions) entry code
     enhancements.  In particular the complex parts of the 64-bit entry
     code have been migrated to C code as well, and a number of dusty
     corners have been refreshed.  (Andy Lutomirski)

   - vDSO special mapping robustification and general cleanups (Andy
     Lutomirski)

   - cpufeature refactoring, cleanups and speedups (Borislav Petkov)

   - lots of other changes ..."

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  x86/cpufeature: Enable new AVX-512 features
  x86/entry/traps: Show unhandled signal for i386 in do_trap()
  x86/entry: Call enter_from_user_mode() with IRQs off
  x86/entry/32: Change INT80 to be an interrupt gate
  x86/entry: Improve system call entry comments
  x86/entry: Remove TIF_SINGLESTEP entry work
  x86/entry/32: Add and check a stack canary for the SYSENTER stack
  x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup
  x86/entry: Only allocate space for tss_struct::SYSENTER_stack if needed
  x86/entry: Vastly simplify SYSENTER TF (single-step) handling
  x86/entry/traps: Clear DR6 early in do_debug() and improve the comment
  x86/entry/traps: Clear TIF_BLOCKSTEP on all debug exceptions
  x86/entry/32: Restore FLAGS on SYSEXIT
  x86/entry/32: Filter NT and speed up AC filtering in SYSENTER
  x86/entry/compat: In SYSENTER, sink AC clearing below the existing FLAGS test
  selftests/x86: In syscall_nt, test NT|TF as well
  x86/asm-offsets: Remove PARAVIRT_enabled
  x86/entry/32: Introduce and use X86_BUG_ESPFIX instead of paravirt_enabled
  uprobes: __create_xol_area() must nullify xol_mapping.fault
  x86/cpufeature: Create a new synthetic cpu capability for machine check recovery
  ...

Signed-off-by: Ingo Molnar <mingo@kernel.org>

 Conflicts:
	kernel/rcu/tree.c
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull NOHZ updates from Ingo Molnar:
 "NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors
  the NOHZ 'can the tick be stopped?' infrastructure and related code to
  be data driven, and harmonizes the naming and handling of all the
  various properties"

[ This makes the ugly "fetch_or()" macro that the scheduler used
  internally a new generic helper, and does a bad job at it.

  I'm pulling it, but I've asked Ingo and Frederic to get this
  fixed up ]

* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched-clock: Migrate to use new tick dependency mask model
  posix-cpu-timers: Migrate to use new tick dependency mask model
  sched: Migrate sched to use new tick dependency mask model
  sched: Account rr tasks
  perf: Migrate perf to use new tick dependency mask model
  nohz: Use enum code for tick stop failure tracing message
  nohz: New tick dependency mask
  nohz: Implement wide kick on top of irq work
  atomic: Export fetch_or()

Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle are:

   - Make schedstats a runtime tunable (disabled by default) and
     optimize it via static keys.

     As most distributions enable CONFIG_SCHEDSTATS=y due to its
     instrumentation value, this is a nice performance enhancement.
     (Mel Gorman)

   - Implement 'simple waitqueues' (swait): these are just pure
     waitqueues without any of the more complex features of full-blown
     waitqueues (callbacks, wake flags, wake keys, etc.).  Simple
     waitqueues have less memory overhead and are faster.

     Use simple waitqueues in the RCU code (in 4 different places) and
     for handling KVM vCPU wakeups.

     (Peter Zijlstra, Daniel Wagner, Thomas Gleixner, Paul Gortmaker,
     Marcelo Tosatti)

   - sched/numa enhancements (Rik van Riel)

   - NOHZ performance enhancements (Rik van Riel)

   - Various sched/deadline enhancements (Steven Rostedt)

   - Various fixes (Peter Zijlstra)

   - ... and a number of other fixes, cleanups and smaller enhancements"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
  sched/cputime: Fix steal_account_process_tick() to always return jiffies
  sched/deadline: Remove dl_new from struct sched_dl_entity
  Revert "kbuild: Add option to turn incompatible pointer check into error"
  sched/deadline: Remove superfluous call to switched_to_dl()
  sched/debug: Fix preempt_disable_ip recording for preempt_disable()
  sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity
  time, acct: Drop irq save & restore from __acct_update_integrals()
  acct, time: Change indentation in __acct_update_integrals()
  sched, time: Remove non-power-of-two divides from __acct_update_integrals()
  sched/rt: Kick RT bandwidth timer immediately on start up
  sched/debug: Add deadline scheduler bandwidth ratio to /proc/sched_debug
  sched/debug: Move sched_domain_sysctl to debug.c
  sched/debug: Move the /sys/kernel/debug/sched_features file setup into debug.c
  sched/rt: Fix PI handling vs. sched_setscheduler()
  sched/core: Remove duplicated sched_group_set_shares() prototype
  sched/fair: Consolidate nohz CPU load update code
  sched/fair: Avoid using decay_load_missed() with a negative value
  sched/deadline: Always calculate end of period on sched_yield()
  sched/cgroup: Fix cgroup entity load tracking tear-down
  rcu: Use simple wait queues where possible in rcutree
  ...

Pull RAS updates from Ingo Molnar:
 "Various RAS updates:

   - AMD MCE support updates for future CPUs, fixes and 'SMCA' (Scalable
     MCA) error decoding support (Aravind Gopalakrishnan)

   - x86 memcpy_mcsafe() support, to enable smart(er) hardware error
     recovery in NVDIMM drivers, based on an extension of the x86
     exception handling code.  (Tony Luck)"

* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  EDAC/sb_edac: Fix computation of channel address
  x86/mm, x86/mce: Add memcpy_mcsafe()
  x86/mce/AMD: Document some functionality
  x86/mce: Clarify comments regarding deferred error
  x86/mce/AMD: Fix logic to obtain block address
  x86/mce/AMD, EDAC: Enable error decoding of Scalable MCA errors
  x86/mce: Move MCx_CONFIG MSR definitions
  x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries
  x86/mm: Expand the exception table logic to allow new handling options
  x86/mce/AMD: Set MCAX Enable bit
  x86/mce/AMD: Carve out threshold block preparation
  x86/mce/AMD: Fix LVT offset configuration for thresholding
  x86/mce/AMD: Reduce number of blocks scanned per bank
  x86/mce/AMD: Do not perform shared bank check for future processors
  x86/mce: Fix order of AMD MCE init function call

Pull perf updates from Ingo Molnar:
 "Main kernel side changes:

   - Big reorganization of the x86 perf support code.  The old code grew
     organically deep inside arch/x86/kernel/cpu/perf* and its naming
     became somewhat messy.

     The new location is under arch/x86/events/, using the following
     cleaner hierarchy of source code files:

       perf/x86: Move perf_event.c .................. => x86/events/core.c
       perf/x86: Move perf_event_amd.c .............. => x86/events/amd/core.c
       perf/x86: Move perf_event_amd_ibs.c .......... => x86/events/amd/ibs.c
       perf/x86: Move perf_event_amd_iommu.[ch] ..... => x86/events/amd/iommu.[ch]
       perf/x86: Move perf_event_amd_uncore.c ....... => x86/events/amd/uncore.c
       perf/x86: Move perf_event_intel_bts.c ........ => x86/events/intel/bts.c
       perf/x86: Move perf_event_intel.c ............ => x86/events/intel/core.c
       perf/x86: Move perf_event_intel_cqm.c ........ => x86/events/intel/cqm.c
       perf/x86: Move perf_event_intel_cstate.c ..... => x86/events/intel/cstate.c
       perf/x86: Move perf_event_intel_ds.c ......... => x86/events/intel/ds.c
       perf/x86: Move perf_event_intel_lbr.c ........ => x86/events/intel/lbr.c
       perf/x86: Move perf_event_intel_pt.[ch] ...... => x86/events/intel/pt.[ch]
       perf/x86: Move perf_event_intel_rapl.c ....... => x86/events/intel/rapl.c
       perf/x86: Move perf_event_intel_uncore.[ch] .. => x86/events/intel/uncore.[ch]
       perf/x86: Move perf_event_intel_uncore_nhmex.c => x86/events/intel/uncore_nmhex.c
       perf/x86: Move perf_event_intel_uncore_snb.c   => x86/events/intel/uncore_snb.c
       perf/x86: Move perf_event_intel_uncore_snbep.c => x86/events/intel/uncore_snbep.c
       perf/x86: Move perf_event_knc.c .............. => x86/events/intel/knc.c
       perf/x86: Move perf_event_p4.c ............... => x86/events/intel/p4.c
       perf/x86: Move perf_event_p6.c ............... => x86/events/intel/p6.c
       perf/x86: Move perf_event_msr.c .............. => x86/events/msr.c

     (Borislav Petkov)

   - Update various x86 PMU constraint and hw support details (Stephane
     Eranian)

   - Optimize kprobes for BPF execution (Martin KaFai Lau)

   - Rewrite, refactor and fix the Intel uncore PMU driver code (Thomas
     Gleixner)

   - Rewrite, refactor and fix the Intel RAPL PMU code (Thomas Gleixner)

   - Various fixes and smaller cleanups.

  There are lots of perf tooling updates as well.  A few highlights:

  perf report/top:

     - Hierarchy histogram mode for 'perf top' and 'perf report',
       showing multiple levels, one per --sort entry: (Namhyung Kim)

       On a mostly idle system:

         # perf top --hierarchy -s comm,dso

       Then expand some levels and use 'P' to take a snapshot:

         # cat perf.hist.0
         -  92.32%         perf
               58.20%         perf
               22.29%         libc-2.22.so
                5.97%         [kernel]
                4.18%         libelf-0.165.so
                1.69%         [unknown]
         -   4.71%         qemu-system-x86
                3.10%         [kernel]
                1.60%         qemu-system-x86_64 (deleted)
         +   2.97%         swapper
         #

     - Add 'L' hotkey to dynamicly set the percent threshold for
       histogram entries and callchains, i.e.  dynamicly do what the
       --percent-limit command line option to 'top' and 'report' does.
       (Namhyung Kim)

  perf mem:

     - Allow specifying events via -e in 'perf mem record', also listing
       what events can be specified via 'perf mem record -e list' (Jiri
       Olsa)

  perf record:

     - Add 'perf record' --all-user/--all-kernel options, so that one
       can tell that all the events in the command line should be
       restricted to the user or kernel levels (Jiri Olsa), i.e.:

         perf record -e cycles:u,instructions:u

       is equivalent to:

         perf record --all-user -e cycles,instructions

     - Make 'perf record' collect CPU cache info in the perf.data file header:

         $ perf record usleep 1
         [ perf record: Woken up 1 times to write data ]
         [ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
         $ perf report --header-only -I | tail -10 | head -8
         # CPU cache info:
         #  L1 Data                 32K [0-1]
         #  L1 Instruction          32K [0-1]
         #  L1 Data                 32K [2-3]
         #  L1 Instruction          32K [2-3]
         #  L2 Unified             256K [0-1]
         #  L2 Unified             256K [2-3]
         #  L3 Unified            4096K [0-3]

       Will be used in 'perf c2c' and eventually in 'perf diff' to
       allow, for instance running the same workload in multiple
       machines and then when using 'diff' show the hardware difference.
       (Jiri Olsa)

     - Improved support for Java, using the JVMTI agent library to do
       jitdumps that then will be inserted in synthesized
       PERF_RECORD_MMAP2 events via 'perf inject' pointed to synthesized
       ELF files stored in ~/.debug and keyed with build-ids, to allow
       symbol resolution and even annotation with source line info, see
       the changeset comments to see how to use it (Stephane Eranian)

  perf script/trace:

     - Decode data_src values (e.g.  perf.data files generated by 'perf
       mem record') in 'perf script': (Jiri Olsa)

         # perf script
           perf 693 [1] 4.088652: 1 cpu/mem-loads,ldlat=30/P: ffff88007d0b0f40 68100142 L1 hit|SNP None|TLB L1 or L2 hit|LCK No <SNIP>
                                                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     - Improve support to 'data_src', 'weight' and 'addr' fields in
       'perf script' (Jiri Olsa)

     - Handle empty print fmts in 'perf script -s' i.e. when running
       python or perl scripts (Taeung Song)

  perf stat:

     - 'perf stat' now shows shadow metrics (insn per cycle, etc) in
       interval mode too.  E.g:

         # perf stat -I 1000 -e instructions,cycles sleep 1
         #         time   counts unit events
            1.000215928  519,620      instructions     #  0.69 insn per cycle
            1.000215928  752,003      cycles
         <SNIP>

     - Port 'perf kvm stat' to PowerPC (Hemant Kumar)

     - Implement CSV metrics output in 'perf stat' (Andi Kleen)

  perf BPF support:

     - Support converting data from bpf events in 'perf data' (Wang Nan)

     - Print bpf-output events in 'perf script': (Wang Nan).

         # perf record -e bpf-output/no-inherit,name=evt/ -e ./test_bpf_output_3.c/map:channel.event=evt/ usleep 1000
         # perf script
            usleep  4882 21384.532523:   evt:  ffffffff810e97d1 sys_nanosleep ([kernel.kallsyms])
             BPF output: 0000: 52 61 69 73 65 20 61 20  Raise a
                         0008: 42 50 46 20 65 76 65 6e  BPF even
                         0010: 74 21 00 00              t!..
             BPF string: "Raise a BPF event!"
         #

     - Add API to set values of map entries in a BPF object, be it
       individual map slots or ranges (Wang Nan)

     - Introduce support for the 'bpf-output' event (Wang Nan)

     - Add glue to read perf events in a BPF program (Wang Nan)

     - Improve support for bpf-output events in 'perf trace' (Wang Nan)

  ... and tons of other changes as well - see the shortlog and git log
  for details!"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (342 commits)
  perf stat: Add --metric-only support for -A
  perf stat: Implement --metric-only mode
  perf stat: Document CSV format in manpage
  perf hists browser: Check sort keys before hot key actions
  perf hists browser: Allow thread filtering for comm sort key
  perf tools: Add sort__has_comm variable
  perf tools: Recalc total periods using top-level entries in hierarchy
  perf tools: Remove nr_sort_keys field
  perf hists browser: Cleanup hist_browser__fprintf_hierarchy_entry()
  perf tools: Remove hist_entry->fmt field
  perf tools: Fix command line filters in hierarchy mode
  perf tools: Add more sort entry check functions
  perf tools: Fix hist_entry__filter() for hierarchy
  perf jitdump: Build only on supported archs
  tools lib traceevent: Add '~' operation within arg_num_eval()
  perf tools: Omit unnecessary cast in perf_pmu__parse_scale
  perf tools: Pass perf_hpp_list all the way through setup_sort_list
  perf tools: Fix perf script python database export crash
  perf jitdump: DWARF is also needed
  perf bench mem: Prepare the x86-64 build for upstream memcpy_mcsafe() changes
  ...

Pull read-only kernel memory updates from Ingo Molnar:
 "This tree adds two (security related) enhancements to the kernel's
  handling of read-only kernel memory:

   - extend read-only kernel memory to a new class of formerly writable
     kernel data: 'post-init read-only memory' via the __ro_after_init
     attribute, and mark the ARM and x86 vDSO as such read-only memory.

     This kind of attribute can be used for data that requires a once
     per bootup initialization sequence, but is otherwise never modified
     after that point.

     This feature was based on the work by PaX Team and Brad Spengler.

     (by Kees Cook, the ARM vDSO bits by David Brown.)

   - make CONFIG_DEBUG_RODATA always enabled on x86 and remove the
     Kconfig option.  This simplifies the kernel and also signals that
     read-only memory is the default model and a first-class citizen.
     (Kees Cook)"

* 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ARM/vdso: Mark the vDSO code read-only after init
  x86/vdso: Mark the vDSO code read-only after init
  lkdtm: Verify that '__ro_after_init' works correctly
  arch: Introduce post-init read-only memory
  x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option
  mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings
  asm-generic: Consolidate mark_rodata_ro()

Pull dma_*_writecombine rename from Ingo Molnar:
 "Rename dma_*_writecombine() to dma_*_wc()

  This is a tree-wide API rename, to move the dma_*() write-combining
  APIs closer in name to their usual API families.  (The old API names
  are kept as compatibility wrappers to not introduce extra breakage.)

  The patch was Coccinelle generated"

* 'mm-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc()

Pull locking changes from Ingo Molnar:
 "Various updates:

   - Futex scalability improvements: remove page lock use for shared
     futex get_futex_key(), which speeds up 'perf bench futex hash'
     benchmarks by over 40% on a 60-core Westmere.  This makes anon-mem
     shared futexes perform close to private futexes.  (Mel Gorman)

   - lockdep hash collision detection and fix (Alfredo Alvarez
     Fernandez)

   - lockdep testing enhancements (Alfredo Alvarez Fernandez)

   - robustify lockdep init by using hlists (Andrew Morton, Andrey
     Ryabinin)

   - mutex and csd_lock micro-optimizations (Davidlohr Bueso)

   - small x86 barriers tweaks (Michael S Tsirkin)

   - qspinlock updates (Waiman Long)"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  locking/csd_lock: Use smp_cond_acquire() in csd_lock_wait()
  locking/csd_lock: Explicitly inline csd_lock*() helpers
  futex: Replace barrier() in unqueue_me() with READ_ONCE()
  locking/lockdep: Detect chain_key collisions
  locking/lockdep: Prevent chain_key collisions
  tools/lib/lockdep: Fix link creation warning
  tools/lib/lockdep: Add tests for AA and ABBA locking
  tools/lib/lockdep: Add userspace version of READ_ONCE()
  tools/lib/lockdep: Fix the build on recent kernels
  locking/qspinlock: Move __ARCH_SPIN_LOCK_UNLOCKED to qspinlock_types.h
  locking/mutex: Allow next waiter lockless wakeup
  locking/pvqspinlock: Enable slowpath locking count tracking
  locking/qspinlock: Use smp_cond_acquire() in pending code
  locking/pvqspinlock: Move lock stealing count tracking code into pv_queued_spin_steal_lock()
  locking/mcs: Fix mcs_spin_lock() ordering
  futex: Remove requirement for lock_page() in get_futex_key()
  futex: Rename barrier references in ordering guarantees
  locking/atomics: Update comment about READ_ONCE() and structures
  locking/lockdep: Eliminate lockdep_init()
  locking/lockdep: Convert hash tables to hlists
  ...

Pull ram resource handling changes from Ingo Molnar:
 "Core kernel resource handling changes to support NVDIMM error
  injection.

  This tree introduces a new I/O resource type, IORESOURCE_SYSTEM_RAM,
  for System RAM while keeping the current IORESOURCE_MEM type bit set
  for all memory-mapped ranges (including System RAM) for backward
  compatibility.

  With this resource flag it no longer takes a strcmp() loop through the
  resource tree to find "System RAM" resources.

  The new resource type is then used to extend ACPI/APEI error injection
  facility to also support NVDIMM"

* 'core-resources-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ACPI/EINJ: Allow memory error injection to NVDIMM
  resource: Kill walk_iomem_res()
  x86/kexec: Remove walk_iomem_res() call with GART type
  x86, kexec, nvdimm: Use walk_iomem_res_desc() for iomem search
  resource: Add walk_iomem_res_desc()
  memremap: Change region_intersects() to take @flags and @desc
  arm/samsung: Change s3c_pm_run_res() to use System RAM type
  resource: Change walk_system_ram() to use System RAM type
  drivers: Initialize resource entry to zero
  xen, mm: Set IORESOURCE_SYSTEM_RAM to System RAM
  kexec: Set IORESOURCE_SYSTEM_RAM for System RAM
  arch: Set IORESOURCE_SYSTEM_RAM flag for System RAM
  ia64: Set System RAM type and descriptor
  x86/e820: Set System RAM type and descriptor
  resource: Add I/O resource descriptor
  resource: Handle resource flags properly
  resource: Add System RAM resource type

Pull irqchip core changes from Jason Cooper:

- mvebu: Update dt binding docs for new odmi driver

Pull MIPS fixes from Ralf Baechle:
 "Another round of MIPS fixes for 4.5:

   - Fix JZ4780 build with DEBUG_ZBOOT and MACH_JZ4780
   - Fix build with DEBUG_ZBOOT and MACH_JZ4780
   - Fix issue with uninitialised temp_foreign_map
   - Fix awk regex compile failure with certain versions of awk.  At
     this time, the sole user, ld-ifversion, is only used on MIPS"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: smp.c: Fix uninitialised temp_foreign_map
  MIPS: Fix build error when SMP is used without GIC
  ld-version: Fix awk regex compile failure
  MIPS: Fix build with DEBUG_ZBOOT and MACH_JZ4780

When calculate_cpu_foreign_map() recalculates the cpu_foreign_map
cpumask it uses the local variable temp_foreign_map without initialising
it to zero. Since the calculation only ever sets bits in this cpumask
any existing bits at that memory location will remain set and find their
way into cpu_foreign_map too. This could potentially lead to cache
operations suboptimally doing smp calls to multiple VPEs in the same
core, even though the VPEs share primary caches.

Therefore initialise temp_foreign_map using cpumask_clear() before use.

Fixes: cccf34e9 ("MIPS: c-r4k: Fix cache flushing for MT cores")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12759/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The MIPS_GIC_IPI should only be selected when MIPS_GIC is also
selected, otherwise it results in a compile error. smp-gic.c uses some
functions from include/linux/irqchip/mips-gic.h like
plat_ipi_call_int_xlate() which are only added to the header file when
MIPS_GIC is set. The Lantiq SoC does not use the GIC, but supports SMP.
The calls top the functions from smp-gic.c are already protected by
some #ifdefs

The first part of this was introduced in commit 72e20142 ("MIPS:
Move GIC IPI functions out of smp-cmp.c")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: stable@vger.kernel.org # v3.15+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12774/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The ld-version.sh script fails on some versions of awk with the
following error, resulting in build failures for MIPS:

awk: scripts/ld-version.sh: line 4: regular expression compile failed (missing '(')

This is due to the regular expression ".*)", meant to strip off the
beginning of the ld version string up to the close bracket, however
brackets have a meaning in regular expressions, so lets escape it so
that awk doesn't expect a corresponding open bracket.

Fixes: ccbef167 ("Kbuild, lto: add ld-version and ld-ifversion ...")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Tested-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Cc: Michal Marek <mmarek@suse.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kbuild@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # 4.4.x-
Patchwork: https://patchwork.linux-mips.org/patch/12838/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Ingenic SoC declares ZBOOT support, but debug definitions are missing
for MACH_JZ4780 resulting in a build failure when DEBUG_ZBOOT is set.
The UART addresses are same as with JZ4740, so fix by covering JZ4780
with those as well.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12830/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Pull block merge fix from Jens Axboe.

This fixes the block segment counting bug and resulting sg overrun
reported by Kent Overstreet, introduced with the last block pull.

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: don't optimize for non-cloned bio in bio_get_last_bvec()

Pull x86 fixes from Ingo Molnar:
 "This fixes 3 FPU handling related bugs, an EFI boot crash and a
  runtime warning.

  The EFI fix arrived late but I didn't want to delay it to after v4.5
  because the effects are pretty bad for the systems that are affected
  by it"

[ Actually, I don't think the EFI fix really matters yet, because we
  haven't switched to the separate EFI page tables in mainline yet ]

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Fix boot crash by always mapping boot service regions into new EFI page tables
  x86/fpu: Fix eager-FPU handling on legacy FPU machines
  x86/delay: Avoid preemptible context checks in delay_mwaitx()
  x86/fpu: Revert ("x86/fpu: Disable AVX when eagerfpu is off")
  x86/fpu: Fix 'no387' regression

Pull SCSI target bug fix from Nicholas Bellinger:
 "Here is an outstanding target-core bug-fix for v4.5 code."

  This patch addresses a recent Task Management (TMR) regression related
  to larger set of multi-port LUN_RESET bug-fixes in v4.5-rc5.

  It drops a left-over target_put_sess_cmd() of se_cmd->cmd_kref within
  ABORT_TASK failure path, once a se_cmd descriptor has already
  completed posting response to fabric driver logic, and must be skipped
  during normal ABORT_TASK se_cmd->tag lookup"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: Drop incorrect ABORT_TASK put for completed commands

For !BIO_CLONED bio, we can use .bi_vcnt safely, but it
doesn't mean we can just simply return .bi_io_vec[.bi_vcnt - 1]
because the start postion may have been moved in the middle of
the bvec, such as splitting in the middle of bvec.

Fixes: 7bcd79ac(block: bio: introduce helpers to get the 1st and last bvec)
Cc: stable@vger.kernel.org
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

A few new AVX-512 instruction groups/features are added in cpufeatures.h
for enuermation: AVX512DQ, AVX512BW, and AVX512VL.

Clear the flags in fpu__xstate_clear_all_cpu_caps().

The specification for latest AVX-512 including the features can be found at:

  https://software.intel.com/sites/default/files/managed/07/b7/319433-023.pdf

Note, I didn't enable the flags in KVM. Hopefully the KVM guys can pick up
the flags and enable them in KVM.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/1457667498-37357-1-git-send-email-fenghua.yu@intel.com
[ Added more detailed feature descriptions. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Some machines have EFI regions in page zero (physical address
0x00000000) and historically that region has been added to the e820
map via trim_bios_range(), and ultimately mapped into the kernel page
tables. It was not mapped via efi_map_regions() as one would expect.

Alexis reports that with the new separate EFI page tables some boot
services regions, such as page zero, are not mapped. This triggers an
oops during the SetVirtualAddressMap() runtime call.

For the EFI boot services quirk on x86 we need to memblock_reserve()
boot services regions until after SetVirtualAddressMap(). Doing that
while respecting the ownership of regions that may have already been
reserved by the kernel was the motivation behind this commit:

  7d68dc3f ("x86, efi: Do not reserve boot services regions within reserved areas")

That patch was merged at a time when the EFI runtime virtual mappings
were inserted into the kernel page tables as described above, and the
trick of setting ->numpages (and hence the region size) to zero to
track regions that should not be freed in efi_free_boot_services()
meant that we never mapped those regions in efi_map_regions(). Instead
we were relying solely on the existing kernel mappings.

Now that we have separate page tables we need to make sure the EFI
boot services regions are mapped correctly, even if someone else has
already called memblock_reserve(). Instead of stashing a tag in
->numpages, set the EFI_MEMORY_RUNTIME bit of ->attribute. Since it
generally makes no sense to mark a boot services region as required at
runtime, it's pretty much guaranteed the firmware will not have
already set this bit.

For the record, the specific circumstances under which Alexis
triggered this bug was that an EFI runtime driver on his machine was
responding to the EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event during
SetVirtualAddressMap().

The event handler for this driver looks like this,

  sub rsp,0x28
  lea rdx,[rip+0x2445] # 0xaa948720
  mov ecx,0x4
  call func_aa9447c0  ; call to ConvertPointer(4, & 0xaa948720)
  mov r11,QWORD PTR [rip+0x2434] # 0xaa948720
  xor eax,eax
  mov BYTE PTR [r11+0x1],0x1
  add rsp,0x28
  ret

Which is pretty typical code for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE
handler. The "mov r11, QWORD PTR [rip+0x2424]" was the faulting
instruction because ConvertPointer() was being called to convert the
address 0x0000000000000000, which when converted is left unchanged and
remains 0x0000000000000000.

The output of the oops trace gave the impression of a standard NULL
pointer dereference bug, but because we're accessing physical
addresses during ConvertPointer(), it wasn't. EFI boot services code
is stored at that address on Alexis' machine.
Reported-by: Alexis Murzeau <amurzeau@gmail.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raphael Hertzog <hertzog@debian.org>
Cc: Roger Shimizu <rogershimizu@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1457695163-29632-2-git-send-email-matt@codeblueprint.co.uk
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=815125Signed-off-by: Ingo Molnar <mingo@kernel.org>

i486 derived cores like Intel Quark support only the very old,
legacy x87 FPU (FSAVE/FRSTOR, CPUID bit FXSR is not set), and
our FPU code wasn't handling the saving and restoring there
properly in the 'eagerfpu' case.

So after we made eagerfpu the default for all CPU types:

  58122bf1 x86/fpu: Default eagerfpu=on on all CPUs

these old FPU designs broke. First, Andy Shevchenko reported a splat:

  WARNING: CPU: 0 PID: 823 at arch/x86/include/asm/fpu/internal.h:163 fpu__clear+0x8c/0x160

which was us trying to execute FXRSTOR on those machines even though
they don't support it.

After taking care of that, Bryan O'Donoghue reported that a simple FPU
test still failed because we weren't initializing the FPU state properly
on those machines.

Take care of all that.
Reported-and-tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20160311113206.GD4312@pd.tnicSigned-off-by: Ingo Molnar <mingo@kernel.org>