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  1. 16 5月, 2017 1 次提交
  3. 18 6月, 2016 1 次提交
    • K
      genirq: Add untracked irq handler · edd14cfe
      由 Keith Busch 提交于 
      This adds a software irq handler for controllers that multiplex
interrupts from multiple devices, but don't know which device generated
the interrupt. For these devices, the irq handler that demuxes must
check every action for every software irq using the same h/w irq in order
to find out which device generated the interrupt. This will inevitably
trigger spurious interrupt detection if we are noting the irq.

The new irq handler does not track the handling for spurious interrupt
detection. An irq that uses this also won't get stats tracked since it
didn't generate the interrupt, nor added to randomness since they are
not random.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: Jon Derrick <jonathan.derrick@intel.com>
Link: http://lkml.kernel.org/r/1466200821-29159-1-git-send-email-keith.busch@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      edd14cfe
  5. 15 2月, 2016 1 次提交
  7. 15 1月, 2016 1 次提交
    • T
      genirq: Validate action before dereferencing it in handle_irq_event_percpu() · 570540d5
      由 Thomas Gleixner 提交于 
      commit 71f64340 changed the handling of irq_desc->action from

CPU 0                   CPU 1
free_irq()              lock(desc)
  lock(desc)            handle_edge_irq()
                        if (desc->action) {
                          handle_irq_event()
                            action = desc->action
                            unlock(desc)
  desc->action = NULL       handle_irq_event_percpu(desc, action)
                              action->xxx
to

CPU 0                   CPU 1
free_irq()              lock(desc)
  lock(desc)            handle_edge_irq()
                        if (desc->action) {
                          handle_irq_event()
                            unlock(desc)
  desc->action = NULL       handle_irq_event_percpu(desc, action)
                              action = desc->action
                              action->xxx

So if free_irq manages to set the action to NULL between the unlock and before
the readout, we happily dereference a null pointer.

We could simply revert 71f64340, but we want to preserve the better code
generation. A simple solution is to change the action loop from a do {} while
to a while {} loop.

This is safe because we either see a valid desc->action or NULL. If the action
is about to be removed it is still valid as free_irq() is blocked on
synchronize_irq().

CPU 0                   CPU 1
free_irq()              lock(desc)
  lock(desc)            handle_edge_irq()
                          handle_irq_event(desc)
                            set(INPROGRESS)
                            unlock(desc)
                            handle_irq_event_percpu(desc)
                            action = desc->action
  desc->action = NULL           while (action) {
                                  action->xxx
                                  ...
                                  action = action->next;
  sychronize_irq()
    while(INPROGRESS);      lock(desc)
                            clr(INPROGRESS)
free(action)

That's basically the same mechanism as we have for shared
interrupts. action->next can become NULL while handle_irq_event_percpu()
runs. Either it sees the action or NULL. It does not matter, because action
itself cannot go away before the interrupt in progress flag has been cleared.

Fixes: commit 71f64340 "genirq: Remove the second parameter from handle_irq_event_percpu()"
Reported-by: zyjzyj2000@gmail.com
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Huang Shijie <shijie.huang@arm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1601131224190.3575@nanos
      570540d5
  9. 09 10月, 2015 2 次提交
  11. 22 9月, 2015 1 次提交
  13. 16 9月, 2015 1 次提交
    • T
      genirq: Remove irq argument from irq flow handlers · bd0b9ac4
      由 Thomas Gleixner 提交于 
      Most interrupt flow handlers do not use the irq argument. Those few
which use it can retrieve the irq number from the irq descriptor.

Remove the argument.

Search and replace was done with coccinelle and some extra helper
scripts around it. Thanks to Julia for her help!
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
      bd0b9ac4
  15. 12 7月, 2015 2 次提交
  17. 22 3月, 2014 1 次提交
  19. 20 2月, 2014 1 次提交
    • T
      genirq: Provide irq_wake_thread() · a92444c6
      由 Thomas Gleixner 提交于 
      In course of the sdhci/sdio discussion with Russell about killing the
sdio kthread hackery we discovered the need to be able to wake an
interrupt thread from software.

The rationale for this is, that sdio hardware can lack proper
interrupt support for certain features. So the driver needs to poll
the status registers, but at the same time it needs to be woken up by
an hardware interrupt.

To be able to get rid of the home brewn kthread construct of sdio we
need a way to wake an irq thread independent of an actual hardware
interrupt.

Provide an irq_wake_thread() function which wakes up the thread which
is associated to a given dev_id. This allows sdio to invoke the irq
thread from the hardware irq handler via the IRQ_WAKE_THREAD return
value and provides a possibility to wake it via a timer for the
polling scenarios. That allows to simplify the sdio logic
significantly.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Chris Ball <chris@printf.net>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140215003823.772565780@linutronix.de
      a92444c6
  21. 15 7月, 2012 1 次提交
  23. 29 3月, 2012 1 次提交
  25. 14 3月, 2012 1 次提交
    • I
      genirq: Flush the irq thread on synchronization · 7140ea19
      由 Ido Yariv 提交于 
      The current implementation does not always flush the threaded handler
when disabling the irq. In case the irq handler was called, but the
threaded handler hasn't started running yet, the interrupt will be
flagged as pending, and the handler will not run. This implementation
has some issues:

First, if the interrupt is a wake source and flagged as pending, the
system will not be able to suspend.

Second, when quickly disabling and re-enabling the irq, the threaded
handler might continue to run after the irq is re-enabled without the
irq handler being called first. This might be an unexpected behavior.

In addition, it might be counter-intuitive that the threaded handler
will not be called even though the irq handler was called and returned
IRQ_WAKE_THREAD.

Fix this by always waiting for the threaded handler to complete in
synchronize_irq().

[ tglx: Massaged comments, added WARN_ONs and the missing
  	IRQTF_RUNTHREAD check in exit_irq_thread() ]
Signed-off-by: NIdo Yariv <ido@wizery.com>
Link: http://lkml.kernel.org/r/1322843052-7166-1-git-send-email-ido@wizery.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      7140ea19
  27. 10 3月, 2012 1 次提交
  29. 03 6月, 2011 1 次提交
  31. 29 3月, 2011 1 次提交
  33. 28 3月, 2011 2 次提交
  35. 26 2月, 2011 2 次提交
    • T
      genirq: Prepare the handling of shared oneshot interrupts · b5faba21
      由 Thomas Gleixner 提交于 
      For level type interrupts we need to track how many threads are on
flight to avoid useless interrupt storms when not all thread handlers
have finished yet. Keep track of the woken threads and only unmask
when there are no more threads in flight.

Yes, I'm lazy and using a bitfield. But not only because I'm lazy, the
main reason is that it's way simpler than using a refcount. A refcount
based solution would need to keep track of various things like
crashing the irq thread, spurious interrupts coming in,
disables/enables, free_irq() and some more. The bitfield keeps the
tracking simple and makes things just work. It's also nicely confined
to the thread code pathes and does not require additional checks all
over the place.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20110223234956.388095876@linutronix.de>
      b5faba21
    • T
      genirq: Make warning in handle_percpu_event useful · 1204e956
      由 Thomas Gleixner 提交于 
      The WARN_ON_ONCE in handle_percpu_event() which emits a warning when
an action handler returns with interrupts enabled is not really
useful. It does not reveal the interrupt number and handler function
which caused it. Make it WARN_ONCE() and add the information.
Reported-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      1204e956
  37. 22 2月, 2011 1 次提交
    • T
      genirq: Use the correct variable for note_interrupt · 70433c01
      由 Thomas Gleixner 提交于 
      note_interrupt wants to be called with the combined result of all
handlers called, not with the last one. If it's a shared interrupt
then the last handler might return IRQ_NONE often enough to trigger
the spurious dectector which turns off a perfectly fine working
interrupt line. Bug was introduced in commit 1277a532(genirq: Simplify
handle_irq_event()).

Yes, I really messed up there. First the variable ret should not have
been named differently to avoid similarity with retval. Second it
should have been declared in the do {} loop.

Rename it to res and move it into the do {} loop and vanish under a
huge brown paperbag.
Reported-bisected-tested-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      70433c01
  39. 19 2月, 2011 6 次提交
  41. 21 1月, 2011 1 次提交
  43. 12 10月, 2010 1 次提交
  45. 04 10月, 2010 9 次提交