[ Upstream commit 12cc923f1ccc1df467e046b02a72c2b3b321b6a2 ]

Nowadays, modern kernel subsystems that use callbacks pass the data
structure associated with a given callback as argument to the callback.
The tasklet subsystem remains one which passes an arbitrary unsigned
long to the callback function. This has several problems:

- This keeps an extra field for storing the argument in each tasklet
  data structure, it bloats the tasklet_struct structure with a redundant
  .data field

- No type checking can be performed on this argument. Instead of
  using container_of() like other callback subsystems, it forces callbacks
  to do explicit type cast of the unsigned long argument into the required
  object type.

- Buffer overflows can overwrite the .func and the .data field, so
  an attacker can easily overwrite the function and its first argument
  to whatever it wants.

Add a new tasklet initialization API, via DECLARE_TASKLET() and
tasklet_setup(), which will replace the existing ones.

This work is greatly inspired by the timer_struct conversion series,
see commit e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()")

To avoid problems with both -Wcast-function-type (which is enabled in
the kernel via -Wextra is several subsystems), and with mismatched
function prototypes when build with Control Flow Integrity enabled,
this adds the "use_callback" member to let the tasklet caller choose
which union member to call through. Once all old API uses are removed,
this and the .data member will be removed as well. (On 64-bit this does
not grow the struct size as the new member fills the hole after atomic_t,
which is also "int" sized.)

Signed-off-by: Romain Perier <romain.perier@gmail.com>
Co-developed-by: Allen Pais <allen.lkml@gmail.com>
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Stable-dep-of: 90b7f2961798 ("net: usb: rtl8150: enable basic endpoint checking")
Signed-off-by: Sasha Levin <sashal@kernel.org>

Pull irq updates from Thomas Gleixner:
 "The irq departement provides the usual mixed bag:

  Core:

   - Further improvements to the irq timings code which aims to predict
     the next interrupt for power state selection to achieve better
     latency/power balance

   - Add interrupt statistics to the core NMI handlers

   - The usual small fixes and cleanups

  Drivers:

   - Support for Renesas RZ/A1, Annapurna Labs FIC, Meson-G12A SoC and
     Amazon Gravition AMR/GIC interrupt controllers.

   - Rework of the Renesas INTC controller driver

   - ACPI support for Socionext SoCs

   - Enhancements to the CSKY interrupt controller

   - The usual small fixes and cleanups"

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
  irq/irqdomain: Fix comment typo
  genirq: Update irq stats from NMI handlers
  irqchip/gic-pm: Remove PM_CLK dependency
  irqchip/al-fic: Introduce Amazon's Annapurna Labs Fabric Interrupt Controller Driver
  dt-bindings: interrupt-controller: Add Amazon's Annapurna Labs FIC
  softirq: Use __this_cpu_write() in takeover_tasklets()
  irqchip/mbigen: Stop printing kernel addresses
  irqchip/gic: Add dependency for ARM_GIC_MAX_NR
  genirq/affinity: Remove unused argument from [__]irq_build_affinity_masks()
  genirq/timings: Add selftest for next event computation
  genirq/timings: Add selftest for irqs circular buffer
  genirq/timings: Add selftest for circular array
  genirq/timings: Encapsulate storing function
  genirq/timings: Encapsulate timings push
  genirq/timings: Optimize the period detection speed
  genirq/timings: Fix timings buffer inspection
  genirq/timings: Fix next event index function
  irqchip/qcom: Use struct_size() in devm_kzalloc()
  irqchip/irq-csky-mpintc: Remove unnecessary loop in interrupt handler
  dt-bindings: interrupt-controller: Update csky mpintc
  ...

The code is executed with interrupts disabled, so it's safe to use
__this_cpu_write().

[ tglx: Massaged changelog ]

Signed-off-by: Muchun Song <smuchun@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: joel@joelfernandes.org
Cc: rostedt@goodmis.org
Cc: frederic@kernel.org
Cc: paulmck@linux.vnet.ibm.com
Cc: alexander.levin@verizon.com
Cc: peterz@infradead.org
Link: https://lkml.kernel.org/r/20190618143305.2038-1-smuchun@gmail.com

Based on 1 normalized pattern(s):

  distribute under gplv2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 8 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190114.475576622@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There are no more users of this interface.
Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Link: https://lkml.kernel.org/r/20190301224821.29843-4-bigeasy@linutronix.de

When a CPU is unplugged the kernel threads of this CPU are parked (see
smpboot_park_threads()). kthread_park() is used to mark each thread as
parked and wake it up, so it can complete the process of parking itselfs
(see smpboot_thread_fn()).

If local softirqs are pending on interrupt exit invoke_softirq() is called
to process the softirqs, however it skips processing when the softirq
kernel thread of the local CPU is scheduled to run. The softirq kthread is
one of the threads that is parked when a CPU is unplugged. Parking the
kthread wakes it up, however only to complete the parking process, not to
process the pending softirqs. Hence processing of softirqs at the end of an
interrupt is skipped, but not done elsewhere, which can result in warnings
about pending softirqs when a CPU is unplugged:

/sys/devices/system/cpu # echo 0 > cpu4/online
[ ... ] NOHZ: local_softirq_pending 02
[ ... ] NOHZ: local_softirq_pending 202
[ ... ] CPU4: shutdown
[ ... ] psci: CPU4 killed.

Don't skip processing of softirqs at the end of an interrupt when the
softirq thread of the CPU is parking.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Link: https://lkml.kernel.org/r/20190128234625.78241-3-mka@chromium.org

Pull irq updates from Thomas Gleixner:
 "The interrupt brigade came up with the following updates:

   - Driver for the Marvell System Error Interrupt machinery

   - Overhaul of the GIC-V3 ITS driver

   - Small updates and fixes all over the place"

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
  genirq: Fix race on spurious interrupt detection
  softirq: Fix typo in __do_softirq() comments
  genirq: Fix grammar s/an /a /
  irqchip/gic: Unify GIC priority definitions
  irqchip/gic-v3: Remove acknowledge loop
  dt-bindings/interrupt-controller: Add documentation for Marvell SEI controller
  dt-bindings/interrupt-controller: Update Marvell ICU bindings
  irqchip/irq-mvebu-icu: Add support for System Error Interrupts (SEI)
  arm64: marvell: Enable SEI driver
  irqchip/irq-mvebu-sei: Add new driver for Marvell SEI
  irqchip/irq-mvebu-icu: Support ICU subnodes
  irqchip/irq-mvebu-icu: Disociate ICU and NSR
  irqchip/irq-mvebu-icu: Clarify the reset operation of configured interrupts
  irqchip/irq-mvebu-icu: Fix wrong private data retrieval
  dt-bindings/interrupt-controller: Fix Marvell ICU length in the example
  genirq/msi: Allow creation of a tree-based irqdomain for platform-msi
  dt-bindings: irqchip: renesas-irqc: Document r8a7744 support
  dt-bindings: irqchip: renesas-irqc: Document R-Car E3 support
  irqchip/pdc: Setup all edge interrupts as rising edge at GIC
  irqchip/gic-v3-its: Allow use of LPI tables in reserved memory
  ...

s/s/as

[ mingo: Also add a missing 'the', add proper punctuation and clarify what 'swap' means here. ]

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: alexander.levin@verizon.com
Cc: frederic@kernel.org
Cc: joel@joelfernandes.org
Cc: paulmck@linux.vnet.ibm.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20181018142133.12341-1-tiny.windzz@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Now that the main RCU API knows about softirq disabling and softirq's
quiescent states, the RCU-bh update code can be dispensed with.
This commit therefore removes the RCU-bh update-side implementation and
defines RCU-bh's update-side API in terms of that of either RCU-preempt or
RCU-sched, depending on the setting of the CONFIG_PREEMPT Kconfig option.

In kernels built with CONFIG_RCU_NOCB_CPU=y this has the knock-on effect
of reducing by one the number of rcuo kthreads per CPU.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

One necessary step towards consolidating the three flavors of RCU is to
make sure that the resulting consolidated "one flavor to rule them all"
correctly handles networking denial-of-service attacks.  One thing that
allows RCU-bh to do so is that __do_softirq() invokes rcu_bh_qs() every
so often, and so something similar has to happen for consolidated RCU.

This must be done carefully.  For example, if a preemption-disabled
region of code takes an interrupt which does softirq processing before
returning, consolidated RCU must ignore the resulting rcu_bh_qs()
invocations -- preemption is still disabled, and that means an RCU
reader for the consolidated flavor.

This commit therefore creates a new rcu_softirq_qs() that is called only
from the ksoftirqd task, thus avoiding the interrupted-a-preempted-region
problem.  This new rcu_softirq_qs() function invokes rcu_sched_qs(),
rcu_preempt_qs(), and rcu_preempt_deferred_qs().  The latter call handles
any deferred quiescent states.

Note that __do_softirq() still invokes rcu_bh_qs().  It will continue to
do so until a later stage of cleanup when the RCU-bh flavor is removed.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Fix !SMP issue located by kbuild test robot. ]