linux.git/kernel/irq/chip.c, branch v4.13

genirq: Restore trigger settings in irq_modify_status()

2017-08-18T10:04:14+00:00

irq_modify_status starts by clearing the trigger settings from
irq_data before applying the new settings, but doesn't restore them,
leaving them to IRQ_TYPE_NONE.

That's pretty confusing to the potential request_irq() that could
follow. Instead, snapshot the settings before clearing them, and restore
them if the irq_modify_status() invocation was not changing the trigger.

Fixes: 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ")
Reported-and-tested-by: jeffy 
Signed-off-by: Marc Zyngier 
Signed-off-by: Thomas Gleixner 
Cc: Jon Hunter 
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170818095345.12378-1-marc.zyngier@arm.com

genirq/PM: Properly pretend disabled state when force resuming interrupts

2017-07-17T20:32:20+00:00

Interrupts with the IRQF_FORCE_RESUME flag set have also the
IRQF_NO_SUSPEND flag set. They are not disabled in the suspend path, but
must be forcefully resumed. That's used by XEN to keep IPIs enabled beyond
the suspension of device irqs. Force resume works by pretending that the
interrupt was disabled and then calling __irq_enable().

Incrementing the disabled depth counter was enough to do that, but with the
recent changes which use state flags to avoid unnecessary hardware access,
this is not longer sufficient. If the state flags are not set, then the
hardware callbacks are not invoked and the interrupt line stays disabled in
"hardware".

Set the disabled and masked state when pretending that an interrupt got
disabled by suspend.

Fixes: bf22ff45bed6 ("genirq: Avoid unnecessary low level irq function calls")
Suggested-by: Thomas Gleixner 
Signed-off-by: Juergen Gross 
Signed-off-by: Thomas Gleixner 
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Link: http://lkml.kernel.org/r/20170717174703.4603-2-jgross@suse.com

Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-07-09T17:24:46+00:00

Pull irq fixes from Thomas Gleixner:

 - A few fixes mopping up the fallout of the big irq overhaul

 - Move the interrupt resource management logic out of the spin locked,
   irq disabled region to avoid unnecessary restrictions of the resource
   callbacks

 - Preparation for reworking the per cpu irq request function.

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqdomain: Allow ACPI device nodes to be used as irqdomain identifiers
  genirq/debugfs: Remove redundant NULL pointer check
  genirq: Allow to pass the IRQF_TIMER flag with percpu irq request
  genirq/timings: Move free timings out of spinlocked region
  genirq: Move irq resource handling out of spinlocked region
  genirq: Add mutex to irq desc to serialize request/free_irq()
  genirq: Move bus locking into __setup_irq()
  genirq: Force inlining of __irq_startup_managed to prevent build failure
  genirq/debugfs: Fix build for !CONFIG_IRQ_DOMAIN

genirq: Force inlining of __irq_startup_managed to prevent build failure

2017-07-04T10:36:44+00:00

If CONFIG_SMP=n, and gcc (e.g. 4.1.2) decides not to inline
__irq_startup_managed(), the build fails with:

    kernel/built-in.o: In function `irq_startup':
    (.text+0x38ed8): undefined reference to `irq_set_affinity_locked'

Fix this by forcing inlining of __irq_startup_managed().

Fixes: 761ea388e8c4e3ac ("genirq: Handle managed irqs gracefully in irq_startup()")
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Thomas Gleixner 
Cc: Arnd Bergmann 
Link: http://lkml.kernel.org/r/1499162761-12398-1-git-send-email-geert@linux-m68k.org

Merge tag 'docs-4.13' of git://git.lwn.net/linux

2017-07-04T04:13:25+00:00

Pull documentation updates from Jonathan Corbet:
 "There has been a fair amount of activity in the docs tree this time
  around. Highlights include:

   - Conversion of a bunch of security documentation into RST

   - The conversion of the remaining DocBook templates by The Amazing
     Mauro Machine. We can now drop the entire DocBook build chain.

   - The usual collection of fixes and minor updates"

* tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits)
  scripts/kernel-doc: handle DECLARE_HASHTABLE
  Documentation: atomic_ops.txt is core-api/atomic_ops.rst
  Docs: clean up some DocBook loose ends
  Make the main documentation title less Geocities
  Docs: Use kernel-figure in vidioc-g-selection.rst
  Docs: fix table problems in ras.rst
  Docs: Fix breakage with Sphinx 1.5 and upper
  Docs: Include the Latex "ifthen" package
  doc/kokr/howto: Only send regression fixes after -rc1
  docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters
  doc: Document suitability of IBM Verse for kernel development
  Doc: fix a markup error in coding-style.rst
  docs: driver-api: i2c: remove some outdated information
  Documentation: DMA API: fix a typo in a function name
  Docs: Insert missing space to separate link from text
  doc/ko_KR/memory-barriers: Update control-dependencies example
  Documentation, kbuild: fix typo "minimun" -> "minimum"
  docs: Fix some formatting issues in request-key.rst
  doc: ReSTify keys-trusted-encrypted.txt
  doc: ReSTify keys-request-key.txt
  ...

genirq: Avoid unnecessary low level irq function calls

2017-06-26T13:47:00+00:00

Check irq state in enable/disable/unmask/mask_irq to avoid unnecessary
low level irq function calls.

This has two advantages:
    - Conditionals are faster than hardware access

    - Solves issues with the underlying refcounting of the pinctrl
      infrastructure

Suggested-by: Thomas Gleixner 
Signed-off-by: Jeffy Chen 
Signed-off-by: Thomas Gleixner 
Cc: tfiga@chromium.org
Cc: briannorris@chromium.org
Cc: dianders@chromium.org
Link: http://lkml.kernel.org/r/1498476814-12563-2-git-send-email-jeffy.chen@rock-chips.com

genirq: Handle managed irqs gracefully in irq_startup()

2017-06-22T16:21:24+00:00

Affinity managed interrupts should keep their assigned affinity accross CPU
hotplug. To avoid magic hackery in device drivers, the core code shall
manage them transparently and set these interrupts into a managed shutdown
state when the last CPU of the assigned affinity mask goes offline. The
interrupt will be restarted when one of the CPUs in the assigned affinity
mask comes back online.

Add the necessary logic to irq_startup(). If an interrupt is requested and
started up, the code checks whether it is affinity managed and if so, it
checks whether a CPU in the interrupts affinity mask is online. If not, it
puts the interrupt into managed shutdown state. 

Signed-off-by: Thomas Gleixner 
Cc: Jens Axboe 
Cc: Marc Zyngier 
Cc: Michael Ellerman 
Cc: Keith Busch 
Cc: Peter Zijlstra 
Cc: Christoph Hellwig 
Link: http://lkml.kernel.org/r/20170619235447.189851170@linutronix.de

genirq: Add force argument to irq_startup()

2017-06-22T16:21:24+00:00

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: Thomas Gleixner 
Cc: Jens Axboe 
Cc: Marc Zyngier 
Cc: Michael Ellerman 
Cc: Keith Busch 
Cc: Peter Zijlstra 
Cc: Christoph Hellwig 
Link: http://lkml.kernel.org/r/20170619235447.112094565@linutronix.de

genirq: Split out irq_startup() code

2017-06-22T16:21:24+00:00

Split out the inner workings of irq_startup() so it can be reused to handle
managed interrupts gracefully.

Signed-off-by: Thomas Gleixner 
Cc: Jens Axboe 
Cc: Marc Zyngier 
Cc: Michael Ellerman 
Cc: Keith Busch 
Cc: Peter Zijlstra 
Cc: Christoph Hellwig 
Link: http://lkml.kernel.org/r/20170619235447.033235144@linutronix.de

genirq: Move initial affinity setup to irq_startup()

2017-06-22T16:21:15+00:00

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: Thomas Gleixner 
Cc: Jens Axboe 
Cc: Marc Zyngier 
Cc: Michael Ellerman 
Cc: Keith Busch 
Cc: Peter Zijlstra 
Cc: Christoph Hellwig 
Link: http://lkml.kernel.org/r/20170619235445.020534783@linutronix.de