Alexander pointed out that the warnons in the regular exit path are
bogus and the thread_mask one actually could be triggered when
__setup_irq() hands out that thread_mask again after __free_irq()
dropped irq_desc->lock.
Thinking more about it, neither IRQTF_RUNTHREAD nor the bit in
thread_mask can be set as this is the regular exit path. We come here
due to:
__free_irq()
remove action from desc
synchronize_irq()
kthread_stop()
So synchronize_irq() makes sure that the thread finished running and
cleaned up both the thread_active count and thread_mask. After that
point nothing can set IRQTF_RUNTHREAD on this action. So the warnons
and the cleanups are pointless.
Reported-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Ido Yariv <ido@wizery.com>
Link: http://lkml.kernel.org/r/20120315190755.GA6732@dhcp-26-207.brq.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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: Ido Yariv <ido@wizery.com>
Link: http://lkml.kernel.org/r/1322843052-7166-1-git-send-email-ido@wizery.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Currently IRQTF_DIED flag is set when a IRQ thread handler calls do_exit()
But also PF_EXITING per process flag gets set when a thread exits. This
fix eliminates the duplicate by using PF_EXITING flag.
Also, there is a race condition in exit_irq_thread(). In case a thread's
bit is cleared in desc->threads_oneshot (and the IRQ line gets unmasked),
but before IRQTF_DIED flag is set, a new interrupt might come in and set
just cleared bit again, this time forever. This fix throws IRQTF_DIED flag
away, eliminating the race as a result.
[ tglx: Test THREAD_EXITING first as suggested by Oleg ]
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/20120309135958.GD2114@dhcp-26-207.brq.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Since 63706172f3 kthread_stop() is not
afraid of dead kernel threads. So no need to check if a thread is
alive before stopping it. These checks still were racy.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/20120309135939.GC2114@dhcp-26-207.brq.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When a new thread handler is created, an irqaction is passed to it as
data. Not only that irqaction is stored in task_struct by the handler
for later use, but also a structure associated with the kernel thread
keeps this value as long as the thread exists.
This fix kicks irqaction out off task_struct. Yes, I introduce new bit
field. But it allows not only to eliminate the duplicate, but also
shortens size of task_struct.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/20120309135925.GB2114@dhcp-26-207.brq.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Xommit ac5637611(genirq: Unmask oneshot irqs when thread was not woken)
fails to unmask when a !IRQ_ONESHOT threaded handler is handled by
handle_level_irq.
This happens because thread_mask is or'ed unconditionally in
irq_wake_thread(), but for !IRQ_ONESHOT interrupts never cleared. So
the check for !desc->thread_active fails and keeps the interrupt
disabled.
Keep the thread_mask zero for !IRQ_ONESHOT interrupts.
Document the thread_mask magic while at it.
Reported-and-tested-by: Sven Joachim <svenjoac@gmx.de>
Reported-and-tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
An interrupt might be pending when irq_startup() is called, but the
startup code does not invoke the resend logic. In some cases this
prevents the device from issuing another interrupt which renders the
device non functional.
Call the resend function in irq_startup() to keep things going.
Reported-and-tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits)
Kconfig: acpi: Fix typo in comment.
misc latin1 to utf8 conversions
devres: Fix a typo in devm_kfree comment
btrfs: free-space-cache.c: remove extra semicolon.
fat: Spelling s/obsolate/obsolete/g
SCSI, pmcraid: Fix spelling error in a pmcraid_err() call
tools/power turbostat: update fields in manpage
mac80211: drop spelling fix
types.h: fix comment spelling for 'architectures'
typo fixes: aera -> area, exntension -> extension
devices.txt: Fix typo of 'VMware'.
sis900: Fix enum typo 'sis900_rx_bufer_status'
decompress_bunzip2: remove invalid vi modeline
treewide: Fix comment and string typo 'bufer'
hyper-v: Update MAINTAINERS
treewide: Fix typos in various parts of the kernel, and fix some comments.
clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR
gpio: Kconfig: drop unknown symbol 'CS5535_GPIO'
leds: Kconfig: Fix typo 'D2NET_V2'
sound: Kconfig: drop unknown symbol ARCH_CLPS7500
...
Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new
kconfig additions, close to removed commented-out old ones)
In irq_wait_for_interrupt(), the should_stop member is verified before
setting the task's state to TASK_INTERRUPTIBLE and calling schedule().
In case kthread_stop sets should_stop and wakes up the process after
should_stop is checked by the irq thread but before the task's state
is changed, the irq thread might never exit:
kthread_stop irq_wait_for_interrupt
------------ ----------------------
...
... while (!kthread_should_stop()) {
kthread->should_stop = 1;
wake_up_process(k);
wait_for_completion(&kthread->exited);
...
set_current_state(TASK_INTERRUPTIBLE);
...
schedule();
}
Fix this by checking if the thread should stop after modifying the
task's state.
[ tglx: Simplified it a bit ]
Signed-off-by: Ido Yariv <ido@wizery.com>
Link: http://lkml.kernel.org/r/1322740508-22640-1-git-send-email-ido@wizery.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
The power management functions related to interrupts do not know
(yet) about per-cpu interrupts and end up calling the wrong
low-level methods to enable/disable interrupts.
This leads to all kind of interesting issues (action taken on one
CPU only, updating a refcount which is not used otherwise...).
The workaround for the time being is simply to flag these interrupts
with IRQF_NO_SUSPEND. At least on ARM, these interrupts are actually
dealt with at the architecture level.
Reported-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1321446459-31409-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
As request_percpu_irq() doesn't allow for a percpu interrupt to have
its type configured (it is generally impossible to configure it on all
CPUs at once), add a 'type' argument to enable_percpu_irq().
This allows some low-level, board specific init code to be switched to
a generic API.
[ tglx: Added WARN_ON argument ]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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 <marc.zyngier@arm.com>
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 <tglx@linutronix.de>
Some irq chips need the irq_set_wake() functionality, but do not
require a irq_set_wake() callback. Instead of forcing an empty
callback to be implemented add a flag which notes this fact. Check for
the flag in set_irq_wake_real() and return success when set.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
This reverts commit f3637a5f2e.
It turns out that this breaks several drivers, one example being OMAP
boards which use the on-board OMAP UARTs and the omap-serial driver that
will not boot to userspace after the commit.
Paul Walmsley reports that enabling CONFIG_DEBUG_SHIRQ reveals 'IRQ
handler type mismatch' errors:
IRQ handler type mismatch for IRQ 74
current handler: serial idle
...
and the reason is that setting IRQF_ONESHOT will now result in those
interrupt handlers having different IRQF flags, and thus being
unsharable. So the commit log in the reverted commit:
"Since it is required for those users and
there is no difference for others it makes sense to add this flag
unconditionally."
is simply not true: there may not be any difference from a "actions at
irq time", but there is a *big* difference wrt this flag testing irq
management (see __setup_irq() in kernel/irq/manage.c).
One solution may be to stop verifying IRQF_ONESHOT in __setup_irq(), but
right now the safe course of action is to revert the change. Let's
revisit this in a later merge window.
Reported-by: Paul Walmsley <paul@pwsan.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Requested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/20110711101731.GA13804@Chamillionaire.breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If no primary handler is specified then a default one is assigned
which always returns IRQ_WAKE_THREAD. This handler requires the
IRQF_ONESHOT flag on LEVEL / EIO typed irqs because the source of
interrupt is not disabled. Since it is required for those users and
there is no difference for others it makes sense to add this flag
unconditionally.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/1310070737-18514-1-git-send-email-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In kernel/irq/manage.c::irq_set_irq_wake() we call
irq_get_desc_buslock() which may return NULL, but the code
dereferences the result unconditionally.
irq_set_irq_wake() has lots of callers - I checked a few and I couldn't
find anything that guarantees that they won't call it with some input that
will cause irq_get_desc_buslock() to return NULL, so I think it's a good
thing to test and -EINVAL was the most sane error code in this situation
that I could think of.
Not all callers test the return value of irq_set_irq_wake(), but those
that do take != 0 to mean error as far as I can see, so they should be
fine. I guess those that don't test actually should, but that's a
different issue.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1106092300360.17868@swampdragon.chaosbits.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The detection of spurios interrupts is currently limited to first level
handler. In force-threaded mode we never notice if the threaded irq does
not feel responsible.
This patch catches the return value of the threaded handler and forwards
it to the spurious detector. If the primary handler returns only
IRQ_WAKE_THREAD then the spourious detector ignores it because it gets
called again from the threaded handler.
[ tglx: Report the erroneous return value early and bail out ]
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/1306824972-27067-2-git-send-email-sebastian@breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This adds support for disabling threading on a per-IRQ basis via the IRQ
status instead of the IRQ flow, which is necessary for interrupts that
don't follow the natural IRQ flow channels, such as those that are
virtually created.
The new APIs added are simply:
irq_set_thread()
irq_set_nothread()
which follow the rest of the IRQ status routines.
Chained handlers also have IRQ_NOTHREAD set on them automatically, making
the lack of threading explicit rather than implicit. Subsequently, the
nothread flag can be viewed through the standard genirq debugging
facilities.
[ tglx: Fixed cleanup fallout ]
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/%3C20110406210135.GF18426%40linux-sh.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The allocated cpumask should be freed in __setup_irq().
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1301744375-6812-1-git-send-email-dfeng@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The late night fixup missed to convert the data type from irq_desc to
irq_data, which results in a harmless but annoying warning.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
I missed the CONFIG_GENERIC_PENDING_IRQ dependency in the affinity
related functions and the IRQ_LEVEL propagation into irq_data
state. Did not pop up on my main test platforms. :(
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Fix new irq-related kernel-doc warnings in 2.6.38:
Warning(kernel/irq/manage.c:149): No description found for parameter 'mask'
Warning(kernel/irq/manage.c:149): Excess function parameter 'cpumask' description in 'irq_set_affinity'
Warning(include/linux/irq.h:161): No description found for parameter 'state_use_accessors'
Warning(include/linux/irq.h:161): Excess struct/union/enum/typedef member 'state_use_accessor' description in 'irq_data'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <20110318093356.b939558d.randy.dunlap@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We really need these flags for some of the interrupt chips. Move it
from internal state to irq_data and provide proper accessors.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Daney <ddaney@caviumnetworks.com>
The .irq_cpu_online() and .irq_cpu_offline() functions may need to
adjust affinity, but they are called with the descriptor lock held.
Create __irq_set_affinity_locked() which is called with the lock held.
Make irq_set_affinity() just a wrapper that acquires the lock.
[ tglx: Changed the argument to irq_data, added a !desc check and
moved the !irq_set_affinity check where it belongs ]
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
LKML-Reference: <1301081931-11240-4-git-send-email-ddaney@caviumnetworks.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
goto out_thread is called before we take the lock. It causes a gcc
warning: "kernel/irq/manage.c:858: warning: ‘flags’ may be used
uninitialized in this function"
[ tglx: Moved unlock before free_cpumask_var() ]
Signed-off-by: Dan Carpenter <error27@gmail.com>
LKML-Reference: <20110317114307.GJ2008@bicker>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add a commandline parameter "threadirqs" which forces all interrupts except
those marked IRQF_NO_THREAD to run threaded. That's mostly a debug option to
allow retrieving better debug data from crashing interrupt handlers. If
"threadirqs" is not enabled on the kernel command line, then there is no
impact in the interrupt hotpath.
Architecture code needs to select CONFIG_IRQ_FORCED_THREADING after
marking the interrupts which cant be threaded IRQF_NO_THREAD. All
interrupts which have IRQF_TIMER set are implict marked
IRQF_NO_THREAD. Also all PER_CPU interrupts are excluded.
Forced threading hard interrupts also forces all soft interrupt
handling into thread context.
When enabled it might slow down things a bit, but for debugging problems in
interrupt code it's a reasonable penalty as it does not immediately
crash and burn the machine when an interrupt handler is buggy.
Some test results on a Core2Duo machine:
Cache cold run of:
# time git grep irq_desc
non-threaded threaded
real 1m18.741s 1m19.061s
user 0m1.874s 0m1.757s
sys 0m5.843s 0m5.427s
# iperf -c server
non-threaded
[ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec
threaded
[ 3] 0.0-10.0 sec 1.09 GBytes 939 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 937 Mbits/sec
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20110223234956.772668648@linutronix.de>
Support ONESHOT on shared interrupts, if all drivers agree on it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20110223234956.483640430@linutronix.de>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20110223234956.388095876@linutronix.de>
The switch case in __irq_set_trigger() lacks a break, which emits a
pr_err unconditionally on success.
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Some irq_chips need to know the state of wakeup mode for
setting the trigger type etc. Reflect it in irq_data state.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
irq_chips, which require to mask the chip before changing the trigger
type should set this flag. So the core takes care of it and the
requirement for looking into desc->status in the chip goes away.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
That's the data structure chip functions get provided. Also allow them
to signal the core code that they updated the flags in irq_data.state
by returning IRQ_SET_MASK_OK_NOCOPY. The default is unchanged.
The type bits should be accessed via:
val = irqd_get_trigger_type(irqdata);
and
irqd_set_trigger_type(irqdata, val);
Coders who access them directly will be tracked down and slapped with
stinking trouts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
That's the right data structure to look at for arch code.
Accessor functions are provided.
irqd_is_per_cpu(irqdata);
irqd_can_balance(irqdata);
Coders who access them directly will be tracked down and slapped with
stinking trouts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The saving of this switch is minimal versus the ifdef mess it
creates. Simple enable PER_CPU unconditionally and remove the config
switch.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
chip implementations need to know about it. Keep status in sync until
all users are fixed.
Accessor function: irqd_is_setaffinity_pending(irqdata)
Coders who access them directly will be tracked down and slapped with
stinking trouts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
