linux-toradex.git/include/linux/irqdesc.h, branch v3.2.73

genirq: Sanitize spurious interrupt detection of threaded irqs

2014-07-11T12:33:34+00:00

commit 1e77d0a1ed7417d2a5a52a7b8d32aea1833faa6c upstream.

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
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1303071450130.22263@ionos
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings

irq: don't put module.h into irq.h for tracking irqgen modules.

2011-10-31T23:32:35+00:00

Recent commit "irq: Track the  owner of irq descriptor" in
commit ID b6873807a7143b7 placed module.h into linux/irq.h
but we are trying to limit module.h inclusion to just C files
that really need it, due to its size and number of children
includes.  This targets just reversing that include.

Add in the basic "struct module" since that is all we really need
to ensure things compile.  In theory, b687380 should have added the
module.h include to the irqdesc.h header as well, but the implicit
module.h everywhere presence masked this from showing up.  So give
it the "struct module" as well.

As for the C files, irqdesc.c is only using THIS_MODULE, so it
does not need module.h - give it export.h instead.  The C file
irq/manage.c is now (as of b687380) using try_module_get and
module_put and so it needs module.h (which it already has).

Also convert the irq_alloc_descs variants to macros, since all
they really do is is call the __irq_alloc_descs primitive.
This avoids including export.h and no debug info is lost.

Signed-off-by: Paul Gortmaker

genirq: Add support for per-cpu dev_id interrupts

2011-10-03T13:35:26+00:00

The ARM GIC interrupt controller offers per CPU interrupts (PPIs),
which are usually used to connect local timers to each core. Each CPU
has its own private interface to the GIC, and only sees the PPIs that
are directly connect to it.

While these timers are separate devices and have a separate interrupt
line to a core, they all use the same IRQ number.

For these devices, request_irq() is not the right API as it assumes
that an IRQ number is visible by a number of CPUs (through the
affinity setting), but makes it very awkward to express that an IRQ
number can be handled by all CPUs, and yet be a different interrupt
line on each CPU, requiring a different dev_id cookie to be passed
back to the handler.

The *_percpu_irq() functions is designed to overcome these
limitations, by providing a per-cpu dev_id vector:

int request_percpu_irq(unsigned int irq, irq_handler_t handler,
		   const char *devname, void __percpu *percpu_dev_id);
void free_percpu_irq(unsigned int, void __percpu *);
int setup_percpu_irq(unsigned int irq, struct irqaction *new);
void remove_percpu_irq(unsigned int irq, struct irqaction *act);
void enable_percpu_irq(unsigned int irq);
void disable_percpu_irq(unsigned int irq);

The API has a number of limitations:
- no interrupt sharing
- no threading
- common handler across all the CPUs

Once the interrupt is requested using setup_percpu_irq() or
request_percpu_irq(), it must be enabled by each core that wishes its
local interrupt to be delivered.

Based on an initial patch by Thomas Gleixner.

Signed-off-by: Marc Zyngier 
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1316793788-14500-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner

irq: Track the owner of irq descriptor

2011-07-28T09:23:21+00:00

Interrupt descriptors can be allocated from modules. The interrupts
are used by other modules, but we have no refcount on the module which
provides the interrupts and there is no way to establish one on the
device level as the interrupt using module is agnostic to the fact
that the interrupt is provided by a module rather than by some builtin
interrupt controller.

To prevent removal of the interrupt providing module, we can track the
owner of the interrupt descriptor, which also provides the relevant
irq chip functions in the irq descriptor.

request/setup_irq() can now acquire a refcount on the owner module to
prevent unloading. free_irq() drops the refcount.

Signed-off-by: Sebastian Andrzej Siewior 
Link: http://lkml.kernel.org/r/20110711101731.GA13804@Chamillionaire.breakpoint.cc
Signed-off-by: Thomas Gleixner

genirq: Uninline and sanity check generic_handle_irq()

2011-05-18T12:59:08+00:00

generic_handle_irq() is missing a NULL pointer check for the result of
irq_to_desc. This was a not a big problem, but we want to expose it to
drivers, so we better have sanity checks in place. Add a return value
as well, which indicates that the irq number was valid and the handler
was invoked.

Based on the pure code move from Jonathan Cameron.

Signed-off-by: Thomas Gleixner 
Cc: Jonathan Cameron

genirq: irq_desc: Document preflow_handler and affinity_hint

2011-04-23T13:56:24+00:00

[ tglx: Filled in the FIXME place holders ]

Signed-off-by: Geert Uytterhoeven 
Link: http://lkml.kernel.org/r/%3C1302426113-13808-2-git-send-email-geert%40linux-m68k.org%3E
Signed-off-by: Thomas Gleixner

genirq: Forgotten updates/deletions after removal of compat code

2011-04-23T13:56:23+00:00

commit 0c6f8a8b917ad361319c8ace3e9f28e69bfdb4c1 ("genirq: Remove compat code")
removed the compat code, but forgot to update some references in comments and
delete some of its documentation.

Signed-off-by: Geert Uytterhoeven 
Link: http://lkml.kernel.org/r/%3C1302426113-13808-1-git-send-email-geert%40linux-m68k.org%3E
Signed-off-by: Thomas Gleixner

genirq: Remove compat code

2011-03-29T12:48:19+00:00

Signed-off-by: Thomas Gleixner

genirq: Provide locked setter for chip, handler, name

2011-03-23T19:22:06+00:00

Some irq_set_type() callbacks need to change the chip and the handler
when the trigger mode changes. We have already a (misnomed) setter
function for the handler which can be called from irq_set_type().

Provide one which allows to set chip and name as well. Put the
misnomed function under the COMPAT switch and provide a replacement.

Signed-off-by: Thomas Gleixner

genirq: Provide a lockdep helper

2011-03-23T19:22:06+00:00

Some irq chips need to call genirq functions for nested chips from
their callbacks. That upsets lockdep. So they need to set a different
lock class for those nested chips. Provide a helper function to avoid
open access to irq_desc.

Signed-off-by: Thomas Gleixner