The case that interrupt affinity setting fails with -EBUSY can be handled
in the kernel completely by using the already available generic pending
infrastructure.

If a irq_chip::set_affinity() fails with -EBUSY, handle it like the
interrupts for which irq_chip::set_affinity() can only be invoked from
interrupt context. Copy the new affinity mask to irq_desc::pending_mask and
set the affinity pending bit. The next raised interrupt for the affected
irq will check the pending bit and try to set the new affinity from the
handler. This avoids that -EBUSY is returned when an affinity change is
requested from user space and the previous change has not been cleaned
up. The new affinity will take effect when the next interrupt is raised
from the device.

Fixes: dccfe314 ("x86/vector: Simplify vector move cleanup")
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NSong Liu <songliubraving@fb.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <liu.song.a23@gmail.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: stable@vger.kernel.org
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tariq Toukan <tariqt@mellanox.com>
Link: https://lkml.kernel.org/r/20180604162224.819273597@linutronix.de

The interrupts are enabled/disabled so the interrupt handler can run
with enabled interrupts while serving the interrupt and not lose other
interrupts especially the timer tick.
If the system runs with force-threaded interrupts then there is no need
to enable the interrupts.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add SPDX identifiers to files

 - which contain an explicit license boiler plate or reference

 - which do not contain a license reference and were not updated in the
   initial SPDX conversion because the license was deduced by the scanners
   via EXPORT_SYMBOL_GPL as GPL2.0 only.

[ tglx: Moved adding identifiers from the patch which removes the
  	references/boilerplate ]
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Link: https://lkml.kernel.org/r/20180314212030.668321222@linutronix.de

Remove pointless references to the file name itself and condense the
information so it wastes less space.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Link: https://lkml.kernel.org/r/20180314212030.412095827@linutronix.de

Given that irq_to_desc() is a radix_tree_lookup and the reverse
operation is only a pointer dereference and that all callers of
__free_irq already have the desc, pass the desc instead of the irq
number.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: kernel@pengutronix.de
Link: https://lkml.kernel.org/r/20180319105202.9794-1-u.kleine-koenig@pengutronix.de

In case of threaded interrupts the thread follows the affinity setting of
the hard interrupt. The related function uses the affinity mask which was
set by either from user space or via one of the kernel mechanisms. This
mask can be wider than the resulting effective affinity of the hard
interrupt. As a consequence the thread might become affine to a completely
different CPU.

Use the effective interrupt affinity if the architecture supports it, so
the hard interrupt and the thread stay on the same CPU.
Reported-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>

If ffz() ever returns a value >= 31 then the following shift is undefined
behaviour because the literal 1 which gets shifted is treated as signed
integer.

In practice, the bug is probably harmless, since the first undefined shift
count is 31 which results - ignoring UB - in (int)(0x80000000). This gets
sign extended so bit 32-63 will be set as well and all subsequent
__setup_irq() calls would just end up hitting the -EBUSY branch.

However, a sufficiently aggressive optimizer may use the UB of 1<<31
to decide that doesn't happen, and hence elide the sign-extension
code, so that subsequent calls can indeed get ffz > 31.

In any case, the right thing to do is to make the literal 1UL.

[ tglx: For this to happen a single interrupt would have to be shared by 32
  	devices. Hardware like that does not exist and would have way more
  	problems than that. ]
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20171030213548.16831-1-linux@rasmusvillemoes.dk

When requesting a shared interrupt, we assume that the firmware
support code (DT or ACPI) has called irqd_set_trigger_type
already, so that we can retrieve it and check that the requester
is being reasonnable.

Unfortunately, we still have non-DT, non-ACPI systems around,
and these guys won't call irqd_set_trigger_type before requesting
the interrupt. The consequence is that we fail the request that
would have worked before.

We can either chase all these use cases (boring), or address it
in core code (easier). Let's have a per-irq_desc flag that
indicates whether irqd_set_trigger_type has been called, and
let's just check it when checking for a shared interrupt.
If it hasn't been set, just take whatever the interrupt
requester asks.

Fixes: 382bd4de ("genirq: Use irqd_get_trigger_type to compare the trigger type for shared IRQs")
Cc: stable@vger.kernel.org
Reported-and-tested-by: NPetr Cvek <petrcvekcz@gmail.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

It is currently unclear how to set the VCPU affinity for a percpu_devid
interrupt , since the Linux irq_data structure describes the state for
multiple interrupts, one for each physical CPU on the system.  Since
each such interrupt can be associated with different VCPUs or none at
all, associating a single VCPU state with such an interrupt does not
capture the necessary semantics.

The implementers of irq_set_affinity are the Intel and AMD IOMMUs, and
the ARM GIC irqchip.  The Intel and AMD callers do not appear to use
percpu_devid interrupts, and the ARM GIC implementation only checks the
pointer against NULL vs. non-NULL.

Therefore, simply update the function documentation to explain the
expected use in the context of percpu_devid interrupts, allowing future
changes or additions to irqchip implementers to do the right thing.
Signed-off-by: NChristoffer Dall <cdall@linaro.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: kvm@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lkml.kernel.org/r/1509093281-15225-13-git-send-email-cdall@linaro.org

Managed interrupts can end up in a stale state on CPU hotplug. If the
interrupt is not targeting a single CPU, i.e. the affinity mask spawns
multiple CPUs then the following can happen:

After boot:

dstate:   0x01601200
            IRQD_ACTIVATED
            IRQD_IRQ_STARTED
            IRQD_SINGLE_TARGET
            IRQD_AFFINITY_SET
            IRQD_AFFINITY_MANAGED
node:     0
affinity: 24-31
effectiv: 24
pending:  0

After offlining CPU 31 - 24

dstate:   0x01a31000
            IRQD_IRQ_DISABLED
            IRQD_IRQ_MASKED
            IRQD_SINGLE_TARGET
            IRQD_AFFINITY_SET
            IRQD_AFFINITY_MANAGED
            IRQD_MANAGED_SHUTDOWN
node:     0
affinity: 24-31
effectiv: 24
pending:  0

Now CPU 25 gets onlined again, so it should get the effective interrupt
affinity for this interruopt, but due to the x86 interrupt affinity setter
restrictions this ends up after restarting the interrupt with:

dstate:   0x01601300
            IRQD_ACTIVATED
            IRQD_IRQ_STARTED
            IRQD_SINGLE_TARGET
            IRQD_AFFINITY_SET
            IRQD_SETAFFINITY_PENDING
            IRQD_AFFINITY_MANAGED
node:     0
affinity: 24-31
effectiv: 24
pending:  24-31

So the interrupt is still affine to CPU 24, which was the last CPU to go
offline of that affinity set and the move to an online CPU within 24-31,
in this case 25, is pending. This mechanism is x86/ia64 specific as those
architectures cannot move interrupts from thread context and do this when
an interrupt is actually handled. So the move is set to pending.

Whats worse is that offlining CPU 25 again results in:

dstate:   0x01601300
            IRQD_ACTIVATED
            IRQD_IRQ_STARTED
            IRQD_SINGLE_TARGET
            IRQD_AFFINITY_SET
            IRQD_SETAFFINITY_PENDING
            IRQD_AFFINITY_MANAGED
node:     0
affinity: 24-31
effectiv: 24
pending:  24-31

This means the interrupt has not been shut down, because the outgoing CPU
is not in the effective affinity mask, but of course nothing notices that
the effective affinity mask is pointing at an offline CPU.

In the case of restarting a managed interrupt the move restriction does not
apply, so the affinity setting can be made unconditional. This needs to be
done _before_ the interrupt is started up as otherwise the condition for
moving it from thread context would not longer be fulfilled.

With that change applied onlining CPU 25 after offlining 31-24 results in:

dstate:   0x01600200
            IRQD_ACTIVATED
            IRQD_IRQ_STARTED
            IRQD_SINGLE_TARGET
            IRQD_AFFINITY_MANAGED
node:     0
affinity: 24-31
effectiv: 25
pending:  

And after offlining CPU 25:

dstate:   0x01a30000
            IRQD_IRQ_DISABLED
            IRQD_IRQ_MASKED
            IRQD_SINGLE_TARGET
            IRQD_AFFINITY_MANAGED
            IRQD_MANAGED_SHUTDOWN
node:     0
affinity: 24-31
effectiv: 25
pending:  

which is the correct and expected result.

Fixes: 761ea388 ("genirq: Handle managed irqs gracefully in irq_startup()")
Reported-by: NYASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: axboe@kernel.dk
Cc: linux-scsi@vger.kernel.org
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: mpe@ellerman.id.au
Cc: Shivasharan Srikanteshwara <shivasharan.srikanteshwara@broadcom.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: keith.busch@intel.com
Cc: peterz@infradead.org
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1710042208400.2406@nanos

Emit a one time warning when the effective affinity mask is enabled in
Kconfig, but the interrupt chip does not update the mask in its
irq_set_affinity() callback,
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710042208400.2406@nanos                                                                                                                                                                                                        

Activation of an interrupt and startup are currently a combo
functionlity. That works so far, but upcoming changes require a strict
separation because the activation can fail in future.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NJuergen Gross <jgross@suse.com>
Tested-by: NYu Chen <yu.c.chen@intel.com>
Acked-by: NJuergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213152.754334077@linutronix.de

Currently the debugfs shows only information about actively used interrupts
like /proc/irq/ does. That's fine for most cases, but not helpful when
internals of allocated, but unused interrupt descriptors have to
debugged. It's also useful to provide information about all descriptors so
leaks can be debugged in a simpler way.

Move the debugfs registration to the descriptor allocation code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NJuergen Gross <jgross@suse.com>
Tested-by: NYu Chen <yu.c.chen@intel.com>
Acked-by: NJuergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213152.355525908@linutronix.de

__free_irq() can return a NULL irqaction for example when trying to free
already-free IRQ, but the callsite unconditionally dereferences the
returned pointer.

Fix this by adding a check and return NULL.
Signed-off-by: NAlexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20170919200412.GA29985@gmail.com

When assigning an interrupt to a vcpu, it is not unlikely that
the level of the hierarchy implementing irq_set_vcpu_affinity
is not the top level (think a generic MSI domain on top of a
virtualization aware interrupt controller).

In such a case, let's iterate over the hierarchy until we find
an irqchip implementing it.
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Moving the irq_request/release_resources() callbacks out of the spinlocked,
irq disabled and bus locked region, unearthed an interesting abuse of the
irq_bus_lock/irq_bus_sync_unlock() callbacks.

The OMAP GPIO driver does merily power management inside of them. The
irq_request_resources() callback of this GPIO irqchip calls a function
which reads a GPIO register. That read aborts now because the clock of the
GPIO block is not magically enabled via the irq_bus_lock() callback.

Move the callbacks under the bus lock again to prevent this. In the
free_irq() path this requires to drop the bus_lock before calling
synchronize_irq() and reaquiring it before calling the
irq_release_resources() callback.

The bus lock can't be held because:

   1) The data which has been changed between bus_lock/un_lock is cached in
      the irq chip driver private data and needs to go out to the irq chip
      via the slow bus (usually SPI or I2C) before calling
      synchronize_irq().

      That's the reason why this bus_lock/unlock magic exists in the first
      place, as you cannot do SPI/I2C transactions while holding desc->lock
      with interrupts disabled.

   2) synchronize_irq() will actually deadlock, if there is a handler on
      flight. These chips use threaded handlers for obvious reasons, as
      they allow to do SPI/I2C communication. When the threaded handler
      returns then bus_lock needs to be taken in irq_finalize_oneshot() as
      we need to talk to the actual irq chip once more. After that the
      threaded handler is marked done, which makes synchronize_irq() return.

      So if we hold bus_lock accross the synchronize_irq() call, the
      handler cannot mark itself done because it blocks on the bus
      lock. That in turn makes synchronize_irq() wait forever on the
      threaded handler to complete....

Add the missing unlock of desc->request_mutex in the error path of
__free_irq() and add a bunch of comments to explain the locking and
protection rules.

Fixes: 46e48e25 ("genirq: Move irq resource handling out of spinlocked region")
Reported-and-tested-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Reported-and-tested-by: NTony Lindgren <tony@atomide.com>
Reported-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Not-longer-ranted-at-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>

The irq timings infrastructure tracks when interrupts occur in order to
statistically predict te next interrupt event.

There is no point to track timer interrupts and try to predict them because
the next expiration time is already known. This can be avoided via the
IRQF_TIMER flag which is passed by timer drivers in request_irq(). It marks
the interrupt as timer based which alloes to ignore these interrupts in the
timings code.

Per CPU interrupts which are requested via request_percpu_+irq() have no
flag argument, so marking per cpu timer interrupts is not possible and they
get tracked pointlessly.

Add __request_percpu_irq() as a variant of request_percpu_irq() with a
flags argument and make request_percpu_irq() an inline wrapper passing
flags = 0.

The flag parameter is restricted to IRQF_TIMER as all other IRQF_ flags
make no sense for per cpu interrupts.

The next step is to convert all existing users of request_percpu_irq() and
then remove the wrapper and the underscores.

[ tglx: Massaged changelog ]
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: peterz@infradead.org
Cc: nicolas.pitre@linaro.org
Cc: vincent.guittot@linaro.org
Cc: rafael@kernel.org
Link: http://lkml.kernel.org/r/1499344144-3964-1-git-send-email-daniel.lezcano@linaro.org

No point to do memory management from a interrupt disabled spin locked
region.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Julia Cartwright <julia@ni.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: linux-rockchip@lists.infradead.org
Cc: John Keeping <john@metanate.com>
Cc: linux-gpio@vger.kernel.org
Link: http://lkml.kernel.org/r/20170629214344.196130646@linutronix.de

Aside of being conceptually wrong, there is also an actual (hard to
trigger and mostly theoretical) problem.

CPU0				CPU1
free_irq(X)			interrupt X
				spin_lock(desc->lock)
				wake irq thread()
				spin_unlock(desc->lock)
spin_lock(desc->lock)
remove action()
shutdown_irq()			
release_resources()		thread_handler()
spin_unlock(desc->lock)		  access released resources.

synchronize_irq()

Move the release resources invocation after synchronize_irq() so it's
guaranteed that the threaded handler has finished.

Move the resource request call out of the desc->lock held region as well,
so the invocation context is the same for both request and release.

This solves the problems with those functions on RT as well.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Julia Cartwright <julia@ni.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: linux-rockchip@lists.infradead.org
Cc: John Keeping <john@metanate.com>
Cc: linux-gpio@vger.kernel.org
Link: http://lkml.kernel.org/r/20170629214344.117028181@linutronix.de

The irq_request/release_resources() callbacks ar currently invoked under
desc->lock with interrupts disabled. This is a source of problems on RT and
conceptually not required.

Add a seperate mutex to struct irq_desc which allows to serialize
request/free_irq(), which can be used to move the resource functions out of
the desc->lock held region.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Julia Cartwright <julia@ni.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: linux-rockchip@lists.infradead.org
Cc: John Keeping <john@metanate.com>
Cc: linux-gpio@vger.kernel.org
Link: http://lkml.kernel.org/r/20170629214344.039220922@linutronix.de

There is no point in having the irq_bus_lock() protection around all
callers to __setup_irq().

Move it into __setup_irq(). This is also a preparatory patch for addressing
the issues with the irq resource callbacks.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Julia Cartwright <julia@ni.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: linux-rockchip@lists.infradead.org
Cc: John Keeping <john@metanate.com>
Cc: linux-gpio@vger.kernel.org
Link: http://lkml.kernel.org/r/20170629214343.960949031@linutronix.de

The interrupt framework gives a lot of information about each interrupt. It
does not keep track of when those interrupts occur though, which is a
prerequisite for estimating the next interrupt arrival for power management
purposes.

Add a mechanism to record the timestamp for each interrupt occurrences in a
per-CPU circular buffer to help with the prediction of the next occurrence
using a statistical model.

Each CPU can store up to IRQ_TIMINGS_SIZE events <irq, timestamp>, the
current value of IRQ_TIMINGS_SIZE is 32.

Each event is encoded into a single u64, where the high 48 bits are used
for the timestamp and the low 16 bits are for the irq number.

A static key is introduced so when the irq prediction is switched off at
runtime, the overhead is near to zero.

It results in most of the code in internals.h for inline reasons and a very
few in the new file timings.c. The latter will contain more in the next patch
which will provide the statistical model for the next event prediction.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/1498227072-5980-1-git-send-email-daniel.lezcano@linaro.org

In order to handle managed interrupts gracefully on irq_startup() so they
won't lose their assigned affinity, it's necessary to allow startups which
keep the interrupts in managed shutdown state, if none of the assigend CPUs
is online. This allows drivers to request interrupts w/o the CPUs being
online, which avoid online/offline churn in drivers.

Add a force argument which can override that decision and let only
request_irq() and enable_irq() allow the managed shutdown
handling. enable_irq() is required, because the interrupt might be
requested with IRQF_NOAUTOEN and enable_irq() invokes irq_startup() which
would then wreckage the assignment again. All other callers force startup
and potentially break the assigned affinity.

No functional change as this only adds the function argument.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235447.112094565@linutronix.de

So that the affinity code can reuse them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170619235445.109426284@linutronix.de

The startup vs. setaffinity ordering of interrupts depends on the
IRQF_NOAUTOEN flag. Chained interrupts are not getting any affinity
assignment at all.

A regular interrupt is started up and then the affinity is set. A
IRQF_NOAUTOEN marked interrupt is not started up, but the affinity is set
nevertheless.

Move the affinity setup to startup_irq() so the ordering is always the same
and chained interrupts get the proper default affinity assigned as well.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235445.020534783@linutronix.de

Rename it with a proper irq_ prefix and make it available for other files
in the core code. Preparatory patch for moving the irq affinity setup
around.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235444.928501004@linutronix.de

No point to have this alloc/free dance of cpumasks. Provide a static mask
for setup_affinity() and protect it proper.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235444.851571573@linutronix.de

Debugging (hierarchical) interupt domains is tedious as there is no
information about the hierarchy and no information about states of
interrupts in the various domain levels.

Add a debugfs directory 'irq' and subdirectories 'domains' and 'irqs'.

The domains directory contains the domain files. The content is information
about the domain. If the domain is part of a hierarchy then the parent
domains are printed as well.

# ls /sys/kernel/debug/irq/domains/
default     INTEL-IR-2	    INTEL-IR-MSI-2  IO-APIC-IR-2  PCI-MSI
DMAR-MSI    INTEL-IR-3	    INTEL-IR-MSI-3  IO-APIC-IR-3  unknown-1
INTEL-IR-0  INTEL-IR-MSI-0  IO-APIC-IR-0    IO-APIC-IR-4  VECTOR
INTEL-IR-1  INTEL-IR-MSI-1  IO-APIC-IR-1    PCI-HT

# cat /sys/kernel/debug/irq/domains/VECTOR 
name:   VECTOR
 size:   0
 mapped: 216
 flags:  0x00000041

# cat /sys/kernel/debug/irq/domains/IO-APIC-IR-0 
name:   IO-APIC-IR-0
 size:   24
 mapped: 19
 flags:  0x00000041
 parent: INTEL-IR-3
    name:   INTEL-IR-3
     size:   65536
     mapped: 167
     flags:  0x00000041
     parent: VECTOR
        name:   VECTOR
         size:   0
         mapped: 216
         flags:  0x00000041

Unfortunately there is no per cpu information about the VECTOR domain (yet).

The irqs directory contains detailed information about mapped interrupts.

# cat /sys/kernel/debug/irq/irqs/3
handler:  handle_edge_irq
status:   0x00004000
istate:   0x00000000
ddepth:   1
wdepth:   0
dstate:   0x01018000
            IRQD_IRQ_DISABLED
            IRQD_SINGLE_TARGET
            IRQD_MOVE_PCNTXT
node:     0
affinity: 0-143
effectiv: 0
pending:  
domain:  IO-APIC-IR-0
 hwirq:   0x3
 chip:    IR-IO-APIC
  flags:   0x10
             IRQCHIP_SKIP_SET_WAKE
 parent:
    domain:  INTEL-IR-3
     hwirq:   0x20000
     chip:    INTEL-IR
      flags:   0x0
     parent:
        domain:  VECTOR
         hwirq:   0x3
         chip:    APIC
          flags:   0x0

This was developed to simplify the debugging of the managed affinity
changes.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235444.537566163@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

In case __irq_set_trigger() fails the resources requested via
irq_request_resources() are not released.

Add the missing release call into the error handling path.

Fixes: c1bacbae ("genirq: Provide irq_request/release_resources chip callbacks")
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/655538f5-cb20-a892-ff15-fbd2dd1fa4ec@gmail.com

Shared interrupts do not go well with disabling auto enable:

1) The sharing interrupt might request it while it's still disabled and
   then wait for interrupts forever.

2) The interrupt might have been requested by the driver sharing the line
   before IRQ_NOAUTOEN has been set. So the driver which expects that
   disabled state after calling request_irq() will not get what it wants.
   Even worse, when it calls enable_irq() later, it will trigger the
   unbalanced enable_irq() warning.
Reported-by: NBrian Norris <briannorris@chromium.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: dianders@chromium.org
Cc: jeffy <jeffy.chen@rock-chips.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: tfiga@chromium.org
Link: http://lkml.kernel.org/r/20170531100212.210682135@linutronix.de

If an interrupt is marked NOAUTOEN then request_irq() installs the action,
but does not enable the interrupt via startup_irq().  The interrupt is
enabled via enable_irq() later from the driver. enable_irq() calls
irq_enable().

That means that for interrupts which have a irq_startup() callback this
callback is never invoked. Neither is irq_domain_activate_irq() invoked for
such interrupts.

If an interrupt depends on irq_startup() or irq_domain_activate_irq() then
the enable via irq_enable() is not enough.

Add a status flag IRQD_IRQ_STARTED_UP and use this to select the proper
mechanism in enable_irq(). Use the flag also to avoid pointless calls into
the low level functions.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: dianders@chromium.org
Cc: jeffy <jeffy.chen@rock-chips.com>
Cc: Brian Norris <briannorris@chromium.org>
Cc: tfiga@chromium.org
Link: http://lkml.kernel.org/r/20170531100212.130986205@linutronix.de

This allows callers to get back at them instead of having to store it in
another variable.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

When requesting a shared irq with IRQF_TRIGGER_NONE then the irqaction
flags get filled with the trigger type from the irq_data:

        if (!(new->flags & IRQF_TRIGGER_MASK))
                new->flags |= irqd_get_trigger_type(&desc->irq_data);

On the first setup_irq() the trigger type in irq_data is NONE when the
above code executes, then the irq is started up for the first time and
then the actual trigger type gets established, but that's too late to fix
up new->flags.

When then a second user of the irq requests the irq with IRQF_TRIGGER_NONE
its irqaction's triggertype gets set to the actual trigger type and the
following check fails:

        if (!((old->flags ^ new->flags) & IRQF_TRIGGER_MASK))

Resulting in the request_irq failing with -EBUSY even though both
users requested the irq with IRQF_SHARED | IRQF_TRIGGER_NONE

Fix this by comparing the new irqaction's trigger type to the trigger type
stored in the irq_data which correctly reflects the actual trigger type
being used for the irq.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/20170415100831.17073-1-hdegoede@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

This fixes the following clang warning when CONFIG_CPUMASK_OFFSTACK=n:

kernel/irq/manage.c:839:28: error: address of array
'desc->irq_common_data.affinity' will always evaluate to 'true'
[-Werror,-Wpointer-bool-conversion]
Signed-off-by: NMatthias Kaehlcke <mka@chromium.org>
Cc: Grant Grundler <grundler@chromium.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Michael Davidson <md@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170412182030.83657-2-mka@chromium.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

sched/headers: Prepare to move the get_task_struct()/put_task_struct() and related APIs from <linux/sched.h> to <linux/sched/task.h>

But first update usage sites with the new header dependency.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

We are going to move scheduler ABI details to <uapi/linux/sched/types.h>,
which will be used from a number of .c files.

Create empty placeholder header that maps to <linux/types.h>.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Fix typos and add the following to the scripts/spelling.txt:

  an user||a user
  an userspace||a userspace

I also added "userspace" to the list since it is a common word in Linux.
I found some instances for "an userfaultfd", but I did not add it to the
list.  I felt it is endless to find words that start with "user" such as
"userland" etc., so must draw a line somewhere.

Link: http://lkml.kernel.org/r/1481573103-11329-4-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The type flags in the irq descriptor are there for historical reasons and
only updated via irq_modify_status() or irq_set_type(). Both functions also
update the type flags in irqdata. __setup_irq() is the only left over user
of the type flags in the irq descriptor.

If __setup_irq() is called with empty irq type flags, then the type flags
are retrieved from irqdata. If an interrupt is shared, then the type flags
are compared with the type flags stored in the irq descriptor. 

On x86 the ioapic does not have a irq_set_type() callback because the type
is defined in the BIOS tables and cannot be changed. The type is stored in
irqdata at setup time without updating the type data in the irq
descriptor. As a result the comparison described above fails.

There is no point in updating the irq descriptor flags because the only
relevant storage is irqdata. Use the type flags from irqdata for both
retrieval and comparison in __setup_irq() instead.

Aside of that the print out in case of non matching type flags has the old
and new type flags arguments flipped. Fix that as well.

For correctness sake the flags stored in the irq descriptor should be
removed, but this is beyond the scope of this bugfix and will be done in a
later patch.

Fixes: 4b357dae ("genirq: Look-up trigger type if not specified by caller")
Reported-and-tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1611072020360.3501@nanosSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The TPS65217 driver grew interrupt support which uses
irq_set_parent(). While it's not yet clear why this is used in the first
place, building the driver as a module fails with:

 ERROR: ".irq_set_parent" [drivers/mfd/tps65217.ko] undefined!

The correctness of the driver change is still investigated, but for now
it's less trouble to export irq_set_parent() than dealing with the build
wreckage.

[ tglx: Rewrote changelog and made the export GPL ]

Fixes: 6556bdac ("mfd: tps65217: Add support for IRQs")
Signed-off-by: NSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Marcin Niestroj <m.niestroj@grinn-global.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Lee Jones <lee.jones@linaro.org>
Link: http://lkml.kernel.org/r/1475775403-27207-1-git-send-email-sudipm.mukherjee@gmail.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>