linux-toradex.git/kernel/irq/manage.c, branch v4.1

genirq: Allow the irqchip state of an IRQ to be save/restored

2015-04-08T21:28:28+00:00

There is a number of cases where a kernel subsystem may want to
introspect the state of an interrupt at the irqchip level:

- When a peripheral is shared between virtual machines,
  its interrupt state becomes part of the guest's state,
  and must be switched accordingly. KVM on arm/arm64 requires
  this for its guest-visible timer
- Some GPIO controllers seem to require peeking into the
  interrupt controller they are connected to to report
  their internal state

This seem to be a pattern that is common enough for the core code
to try and support this without too many horrible hacks. Introduce
a pair of accessors (irq_get_irqchip_state/irq_set_irqchip_state)
to retrieve the bits that can be of interest to another subsystem:
pending, active, and masked.

- irq_get_irqchip_state returns the state of the interrupt according
  to a parameter set to IRQCHIP_STATE_PENDING, IRQCHIP_STATE_ACTIVE,
  IRQCHIP_STATE_MASKED or IRQCHIP_STATE_LINE_LEVEL.
- irq_set_irqchip_state similarly sets the state of the interrupt.

Signed-off-by: Marc Zyngier 
Reviewed-by: Bjorn Andersson 
Tested-by: Bjorn Andersson 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Abhijeet Dharmapurikar 
Cc: Stephen Boyd 
Cc: Phong Vo 
Cc: Linus Walleij 
Cc: Tin Huynh 
Cc: Y Vo 
Cc: Toan Le 
Cc: Bjorn Andersson 
Cc: Jason Cooper 
Cc: Arnd Bergmann 
Link: http://lkml.kernel.org/r/1426676484-21812-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner

Merge branch 'linus' into irq/core to get the GIC updates which

2015-04-08T21:26:21+00:00

conflict with pending GIC changes.

Conflicts:
	drivers/usb/isp1760/isp1760-core.c

genirq / PM: Add flag for shared NO_SUSPEND interrupt lines

2015-03-04T20:42:19+00:00

It currently is required that all users of NO_SUSPEND interrupt
lines pass the IRQF_NO_SUSPEND flag when requesting the IRQ or the
WARN_ON_ONCE() in irq_pm_install_action() will trigger.  That is
done to warn about situations in which unprepared interrupt handlers
may be run unnecessarily for suspended devices and may attempt to
access those devices by mistake.  However, it may cause drivers
that have no technical reasons for using IRQF_NO_SUSPEND to set
that flag just because they happen to share the interrupt line
with something like a timer.

Moreover, the generic handling of wakeup interrupts introduced by
commit 9ce7a25849e8 (genirq: Simplify wakeup mechanism) only works
for IRQs without any NO_SUSPEND users, so the drivers of wakeup
devices needing to use shared NO_SUSPEND interrupt lines for
signaling system wakeup generally have to detect wakeup in their
interrupt handlers.  Thus if they happen to share an interrupt line
with a NO_SUSPEND user, they also need to request that their
interrupt handlers be run after suspend_device_irqs().

In both cases the reason for using IRQF_NO_SUSPEND is not because
the driver in question has a genuine need to run its interrupt
handler after suspend_device_irqs(), but because it happens to
share the line with some other NO_SUSPEND user.  Otherwise, the
driver would do without IRQF_NO_SUSPEND just fine.

To make it possible to specify that condition explicitly, introduce
a new IRQ action handler flag for shared IRQs, IRQF_COND_SUSPEND,
that, when set, will indicate to the IRQ core that the interrupt
user is generally fine with suspending the IRQ, but it also can
tolerate handler invocations after suspend_device_irqs() and, in
particular, it is capable of detecting system wakeup and triggering
it as appropriate from its interrupt handler.

That will allow us to work around a problem with a shared timer
interrupt line on at91 platforms.

Link: http://marc.info/?l=linux-kernel&m=142252777602084&w=2
Link: http://marc.info/?t=142252775300011&r=1&w=2
Link: https://lkml.org/lkml/2014/12/15/552
Reported-by: Boris Brezillon 
Signed-off-by: Rafael J. Wysocki 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Mark Rutland

genirq: Provide disable_hardirq()

2015-02-18T14:08:33+00:00

For things like netpoll there is a need to disable an interrupt from
atomic context. Currently netpoll uses disable_irq() which will
sleep-wait on threaded handlers and thus forced_irqthreads breaks
things.

Provide disable_hardirq(), which uses synchronize_hardirq() to only wait
for active hardirq handlers; also change synchronize_hardirq() to
return the status of threaded handlers.

This will allow one to try-disable an interrupt from atomic context, or
in case of request_threaded_irq() to only wait for the hardirq part.

Suggested-by: Sabrina Dubroca 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Arnd Bergmann 
Cc: David Miller 
Cc: Eyal Perry 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Quentin Lambert 
Cc: Randy Dunlap 
Cc: Russell King 
Link: http://lkml.kernel.org/r/20150205130623.GH5029@twins.programming.kicks-ass.net
[ Fixed typos and such. ]
Signed-off-by: Ingo Molnar

genirq: Fix null pointer reference in irq_set_affinity_hint()

2015-02-09T17:47:42+00:00

The recent set_affinity commit by me introduced some null
pointer dereferences on driver unload, because some drivers
call this function with a NULL argument. This fixes the issue
by just checking for null before setting the affinity mask.

Fixes: e2e64a932556 ("genirq: Set initial affinity in irq_set_affinity_hint()")
Reported-by: Yinghai Lu 
Signed-off-by: Jesse Brandeburg 
CC: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20150128185739.9689.84588.stgit@jbrandeb-cp2.jf.intel.com
Signed-off-by: Ingo Molnar

genirq: Set initial affinity in irq_set_affinity_hint()

2015-01-23T10:38:25+00:00

Problem:
The default behavior of the kernel is somewhat undesirable as all
requested interrupts end up on CPU0 after registration.  A user can
run irqbalance daemon, or can manually configure smp_affinity via the
proc filesystem, but the default affinity of the interrupts for all
devices is always CPU zero, this can cause performance problems or
very heavy cpu use of only one core if not noticed and fixed by the
user.

Solution:
Enable the setting of the initial affinity directly when the driver
sets a hint.

This enabling means that kernel drivers can include an initial
affinity setting for the interrupt, instead of all interrupts starting
out life on CPU0. Of course if irqbalance is still running then the
interrupts will get moved as before.

This function is currently called by drivers in block, crypto,
infiniband, ethernet and scsi trees, but only a handful, so these will
be the devices affected by this change.

Tested on i40e, and default interrupts were spread across the CPUs
according to the hint.

drivers/block/mtip32xx/mtip32xx.c:3
drivers/block/nvme-core.c:2
drivers/crypto/qat/qat_dh895xcc/adf_isr.c:3
drivers/infiniband/hw/qib/qib_iba7322.c:2
drivers/net/ethernet/intel/i40e/i40e_main.c:3
drivers/net/ethernet/intel/i40evf/i40evf_main.c:3
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:3
drivers/net/ethernet/mellanox/mlx4/en_cq.c:2
drivers/scsi/hpsa.c:3
drivers/scsi/lpfc/lpfc_init.c:3
drivers/scsi/megaraid/megaraid_sas_base.c:8
drivers/soc/ti/knav_qmss_acc.c:1
drivers/soc/ti/knav_qmss_queue.c:2
drivers/virtio/virtio_pci_common.c:2

Signed-off-by: Jesse Brandeburg 
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20141219012206.4220.27491.stgit@jbrandeb-cp2.jf.intel.com
Signed-off-by: Thomas Gleixner

genirq: Add IRQ_SET_MASK_OK_DONE to support stacked irqchip

2014-11-23T12:01:46+00:00

Add IRQ_SET_MASK_OK_DONE in addition to IRQ_SET_MASK_OK and
IRQ_SET_MASK_OK_NOCOPY to support stacked irqchip. IRQ_SET_MASK_OK_DONE
is the same as IRQ_SET_MASK_OK to irq core. To stacked irqchip, it means
that ascendant irqchips have done all the work and no more handling
needed in descendant irqchips.

Signed-off-by: Jiang Liu 
Cc: Bjorn Helgaas 
Cc: Grant Likely 
Cc: Marc Zyngier 
Cc: Yingjoe Chen 
Cc: Yijing Wang 
Signed-off-by: Thomas Gleixner

genirq: Add sanity checks for PM options on shared interrupt lines

2014-09-01T11:48:05+00:00

Account the IRQF_NO_SUSPEND and IRQF_RESUME_EARLY actions on shared
interrupt lines and yell loudly if there is a mismatch.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Rafael J. Wysocki

genirq: Move suspend/resume logic into irq/pm code

2014-09-01T11:47:57+00:00

No functional change. Preparatory patch for cleaning up the suspend
abort functionality. Update the comments while at it.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Rafael J. Wysocki

genirq: Sanitize spurious interrupt detection of threaded irqs

2014-05-03T21:15:39+00:00

Till reported that the spurious interrupt detection of threaded
interrupts is broken in two ways:

- note_interrupt() is called for each action thread of a shared
  interrupt line. That's wrong as we are only interested whether none
  of the device drivers felt responsible for the interrupt, but by
  calling multiple times for a single interrupt line we account
  IRQ_NONE even if one of the drivers felt responsible.

- note_interrupt() when called from the thread handler is not
  serialized. That leaves the members of irq_desc which are used for
  the spurious detection unprotected.

To solve this we need to defer the spurious detection of a threaded
interrupt to the next hardware interrupt context where we have
implicit serialization.

If note_interrupt is called with action_ret == IRQ_WAKE_THREAD, we
check whether the previous interrupt requested a deferred check. If
not, we request a deferred check for the next hardware interrupt and
return. 

If set, we check whether one of the interrupt threads signaled
success. Depending on this information we feed the result into the
spurious detector.

If one primary handler of a shared interrupt returns IRQ_HANDLED we
disable the deferred check of irq threads on the same line, as we have
found at least one device driver who cared.

Reported-by: Till Straumann 
Signed-off-by: Thomas Gleixner 
Tested-by: Austin Schuh 
Cc: Oliver Hartkopp 
Cc: Wolfgang Grandegger 
Cc: Pavel Pisa 
Cc: Marc Kleine-Budde 
Cc: linux-can@vger.kernel.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1303071450130.22263@ionos