A small number of users of IRQF_TIMER are using it for the implied no
suspend behaviour on interrupts which are not timer interrupts.
Therefore add a new IRQF_NO_SUSPEND flag, rename IRQF_TIMER to
__IRQF_TIMER and redefine IRQF_TIMER in terms of these new flags.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: xen-devel@lists.xensource.com
Cc: linux-input@vger.kernel.org
Cc: linuxppc-dev@ozlabs.org
Cc: devicetree-discuss@lists.ozlabs.org
LKML-Reference: <1280398595-29708-1-git-send-email-ian.campbell@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The set_type() function can change the chip implementation when the
trigger mode changes. That might result in using an non-initialized
irq chip when called from __setup_irq() or when called via
set_irq_type() on an already enabled irq.
The set_irq_type() function should not be called on an enabled irq,
but because we forgot to put a check into it, we have a bunch of users
which grew the habit of doing that and it never blew up as the
function is serialized via desc->lock against all users of desc->chip
and they never hit the non-initialized irq chip issue.
The easy fix for the __setup_irq() issue would be to move the
irq_chip_set_defaults(desc->chip) call after the trigger setting to
make sure that a chip change is covered.
But as we have already users, which do the type setting after
request_irq(), the safe fix for now is to call irq_chip_set_defaults()
from __irq_set_trigger() when desc->set_type() changed the irq chip.
It needs a deeper analysis whether we should refuse to change the chip
on an already enabled irq, but that'd be a large scale change to fix
all the existing users. So that's neither stable nor 2.6.35 material.
Reported-by: Esben Haabendal <eha@doredevelopment.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: stable@kernel.org
When an interrupt is disabled and torn down, the CPU mask returned
through affinity_hint right now is all CPUs. Also, for drivers that
don't provide an affinity_hint mask, this can be misleading. There
should be no hint at all, meaning an empty CPU mask.
[ tglx: use zalloc_cpumask_var instead of clearing it under the lock ]
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Cc: davem@davemloft.net
Cc: arjan@linux.jf.intel.com
Cc: bhutchings@solarflare.com
LKML-Reference: <20100505205638.5426.87189.stgit@ppwaskie-hc2.jf.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch adds a cpumask affinity hint to the irq_desc structure,
along with a registration function and a read-only proc entry for each
interrupt.
This affinity_hint handle for each interrupt can be used by underlying
drivers that need a better mechanism to control interrupt affinity.
The underlying driver can register a cpumask for the interrupt, which
will allow the driver to provide the CPU mask for the interrupt to
anything that requests it. The intent is to extend the userspace
daemon, irqbalance, to help hint to it a preferred CPU mask to balance
the interrupt into.
[ tglx: Fixed compile warnings, added WARN_ON, made SMP only ]
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Cc: davem@davemloft.net
Cc: arjan@linux.jf.intel.com
Cc: bhutchings@solarflare.com
LKML-Reference: <20100430214445.3992.41647.stgit@ppwaskie-hc2.jf.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Remove all code which is related to IRQF_DISABLED from the core kernel
code. IRQF_DISABLED still exists as a flag, but becomes a NOOP and
will be removed after a grace period. That way we can easily revert to
the previous behaviour by just restoring the core code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@osdl.org>
LKML-Reference: <20100326000405.991244690@linutronix.de>
Running interrupt handlers with interrupts enabled can cause stack
overflows. That has been observed with multiqueue NICs delivering all
their interrupts to a single core. We might band aid that somehow by
checking the interrupt stacks, but the real safe fix is to run the irq
handlers with interrupts disabled.
Drivers for whacky hardware still can reenable them in the handler
itself, if the need arises. (They do already due to lockdep)
The risk of doing this is rather low:
- lockdep already enforces this
- CONFIG_NOHZ has shaken out the drivers which relied on jiffies updates
- time keeping is not longer sensitive to the timer interrupt being delayed
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@osdl.org>
LKML-Reference: <20100326000405.758579387@linutronix.de>
Now that we enjoy threaded interrupts, we're starting to see irq_chip
implementations (wm831x, pca953x) that make use of threaded interrupts
for the controller, and nested interrupts for the client interrupt. It
all works very well, with one drawback:
Drivers requesting an IRQ must now know whether the handler will
run in a thread context or not, and call request_threaded_irq() or
request_irq() accordingly.
The problem is that the requesting driver sometimes doesn't know
about the nature of the interrupt, specially when the interrupt
controller is a discrete chip (typically a GPIO expander connected
over I2C) that can be connected to a wide variety of otherwise perfectly
supported hardware.
This patch introduces the request_any_context_irq() function that mostly
mimics the usual request_irq(), except that it checks whether the irq
level is configured as nested or not, and calls the right backend.
On success, it also returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
[ tglx: Made return value an enum, simplified code and made the export
of request_any_context_irq GPL ]
Signed-off-by: Marc Zyngier <maz@misterjones.org>
Cc: <joachim.eastwood@jotron.com>
LKML-Reference: <927ea285bd0c68934ddae1a47e44a9ba@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: Force MSI irq handlers to run with interrupts disabled
Network folks reported that directing all MSI-X vectors of their multi
queue NICs to a single core can cause interrupt stack overflows when
enough interrupts fire at the same time.
This is caused by the fact that we run interrupt handlers by default
with interrupts enabled unless the driver reuqests the interrupt with
the IRQF_DISABLED set. The NIC handlers do not set this flag, so
simultaneous interrupts can nest unlimited and cause the stack
overflow.
The only safe counter measure is to run the interrupt handlers with
interrupts disabled. We can't switch to this mode in general right
now, but it is safe to do so for MSI interrupts.
Force IRQF_DISABLED for MSI interrupt handlers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Linus Torvalds <torvalds@osdl.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: David Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: stable@kernel.org
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: Move two IRQ functions from .init.text to .text
genirq: Protect access to irq_desc->action in can_request_irq()
genirq: Prevent oneshot irq thread race
Both functions should not be marked as __init, since they be called
from modules after the init section is freed.
Signed-off-by: Henrik Kretzschmar <henne@nachtwindheim.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jkosina@suse.cz>
LKML-Reference: <1269431961-5731-1-git-send-email-henne@nachtwindheim.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
can_request_irq() accesses and dereferences irq_desc->action w/o
holding irq_desc->lock. So action can be freed on another CPU before
it's dereferenced. Unlikely, but ...
Protect it with desc->lock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Expose irq_desc->node as /proc/irq/*/node.
This file provides device hardware locality information for apps
desiring to include hardware locality in irq mapping decisions.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Lars-Peter pointed out that the oneshot threaded interrupt handler
code has the following race:
CPU0 CPU1
hande_level_irq(irq X)
mask_ack_irq(irq X)
handle_IRQ_event(irq X)
wake_up(thread_handler)
thread handler(irq X) runs
finalize_oneshot(irq X)
does not unmask due to
!(desc->status & IRQ_MASKED)
return from irq
does not unmask due to
(desc->status & IRQ_ONESHOT)
This leaves the interrupt line masked forever.
The reason for this is the inconsistent handling of the IRQ_MASKED
flag. Instead of setting it in the mask function the oneshot support
sets the flag after waking up the irq thread.
The solution for this is to set/clear the IRQ_MASKED status whenever
we mask/unmask an interrupt line. That's the easy part, but that
cleanup opens another race:
CPU0 CPU1
hande_level_irq(irq)
mask_ack_irq(irq)
handle_IRQ_event(irq)
wake_up(thread_handler)
thread handler(irq) runs
finalize_oneshot_irq(irq)
unmask(irq)
irq triggers again
handle_level_irq(irq)
mask_ack_irq(irq)
return from irq due to IRQ_INPROGRESS
return from irq
does not unmask due to
(desc->status & IRQ_ONESHOT)
This requires that we synchronize finalize_oneshot_irq() with the
primary handler. If IRQ_INPROGESS is set we wait until the primary
handler on the other CPU has returned before unmasking the interrupt
line again.
We probably have never seen that problem because it does not happen on
UP and on SMP the irqbalancer protects us by pinning the primary
handler and the thread to the same CPU.
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Use radix_tree irq_desc_tree instead of irq_desc_ptrs.
-v2: according to Eric and cyrill to use radix_tree_lookup_slot and
radix_tree_replace_slot
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-32-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Add replace_irq_desc() instead of poking at the array directly.
-v2: remove unneeded boundary check in replace_irq_desc
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-31-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
mem_init is moved early already.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-29-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Keep chip_data in create_irq_nr and destroy_irq.
When two drivers are setting up MSI-X at the same time via
pci_enable_msix() there is a race. See this dmesg excerpt:
[ 85.170610] ixgbe 0000:02:00.1: irq 97 for MSI/MSI-X
[ 85.170611] alloc irq_desc for 99 on node -1
[ 85.170613] igb 0000:08:00.1: irq 98 for MSI/MSI-X
[ 85.170614] alloc kstat_irqs on node -1
[ 85.170616] alloc irq_2_iommu on node -1
[ 85.170617] alloc irq_desc for 100 on node -1
[ 85.170619] alloc kstat_irqs on node -1
[ 85.170621] alloc irq_2_iommu on node -1
[ 85.170625] ixgbe 0000:02:00.1: irq 99 for MSI/MSI-X
[ 85.170626] alloc irq_desc for 101 on node -1
[ 85.170628] igb 0000:08:00.1: irq 100 for MSI/MSI-X
[ 85.170630] alloc kstat_irqs on node -1
[ 85.170631] alloc irq_2_iommu on node -1
[ 85.170635] alloc irq_desc for 102 on node -1
[ 85.170636] alloc kstat_irqs on node -1
[ 85.170639] alloc irq_2_iommu on node -1
[ 85.170646] BUG: unable to handle kernel NULL pointer dereference
at 0000000000000088
As you can see igb and ixgbe are both alternating on create_irq_nr()
via pci_enable_msix() in their probe function.
ixgbe: While looping through irq_desc_ptrs[] via create_irq_nr() ixgbe
choses irq_desc_ptrs[102] and exits the loop, drops vector_lock and
calls dynamic_irq_init. Then it sets irq_desc_ptrs[102]->chip_data =
NULL via dynamic_irq_init().
igb: Grabs the vector_lock now and starts looping over irq_desc_ptrs[]
via create_irq_nr(). It gets to irq_desc_ptrs[102] and does this:
cfg_new = irq_desc_ptrs[102]->chip_data;
if (cfg_new->vector != 0)
continue;
This hits the NULL deref.
Another possible race exists via pci_disable_msix() in a driver or in
the number of error paths that call free_msi_irqs():
destroy_irq()
dynamic_irq_cleanup() which sets desc->chip_data = NULL
...race window...
desc->chip_data = cfg;
Remove the save and restore code for cfg in create_irq_nr() and
destroy_irq() and take the desc->lock when checking the irq_cfg.
Reported-and-analyzed-by: Brandon Philips <bphilips@suse.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-3-git-send-email-yinghai@kernel.org>
Signed-off-by: Brandon Phililps <bphilips@suse.de>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
* 'timers-for-linus-ntp' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ntp: Provide compability defines (You say MOD_NANO, I say ADJ_NANO)
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: do not execute DEBUG_SHIRQ when irq setup failed
single_open data argument must be PDE(inode)->data instead of NULL
otherwise seq_file->private is always NULL and we always read the
spurious data of irq 0.
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ tglx: compacted it a bit ]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
LKML-Reference: <20090828181743.GA14050@x200.localdomain>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If a parent directory (ie /proc/irq/<irq>) could not be created
we should not attempt to create subdirectories. Otherwise it
would lead that "smp_affinity" and "spurious" entries are may be
registered under /proc root instead of a proper place.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20091026202811.GD5321@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit 74296a8ed added this function for debug purposes, but it was
never used for anything. Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix docbook comments to match the actual function names
(set_irq_msi, handle_percpu_irq).
Signed-off-by: Liuwenyi <qingshenlwy@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* 'irq-threaded-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: Do not mask oneshot edge type interrupts
genirq: Support nested threaded irq handling
genirq: Add buslock support
genirq: Add oneshot support
when there is no ram on node 0.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <4A95C32D.5040605@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Masking oneshot edge type interrupts is wrong as we might lose an
interrupt which is issued when the threaded handler is handling the
device. We can keep the irq unmasked safely as with edge type
interrupts there is no danger of interrupt floods. If the threaded
handler has not yet finished then IRQTF_RUNTHREAD is set which will
keep the handler thread active.
Debugged and verified in preempt-rt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The wake_up_process() of the new irq thread in __setup_irq() is too
early as the irqaction is not yet fully initialized especially
action->irq is not yet set. The interrupt thread might dereference the
wrong irq descriptor.
Move the wakeup after the action is installed and action->irq has been
set.
Reported-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Buesch <mb@bu3sch.de>
Interrupt chips which are behind a slow bus (i2c, spi ...) and
demultiplex other interrupt sources need to run their interrupt
handler in a thread.
The demultiplexed interrupt handlers need to run in thread context as
well and need to finish before the demux handler thread can reenable
the interrupt line. So the easiest way is to run the sub device
handlers in the context of the demultiplexing handler thread.
To avoid that a separate thread is created for the subdevices the
function set_nested_irq_thread() is provided which sets the
IRQ_NESTED_THREAD flag in the interrupt descriptor.
A driver which calls request_threaded_irq() must not be aware of the
fact that the threaded handler is called in the context of the
demultiplexing handler thread. The setup code checks the
IRQ_NESTED_THREAD flag which was set from the irq chip setup code and
does not setup a separate thread for the interrupt. The primary
function which is provided by the device driver is replaced by an
internal dummy function which warns when it is called.
For the demultiplexing handler a helper function handle_nested_irq()
is provided which calls the demux interrupt thread function in the
context of the caller and does the proper interrupt accounting and
takes the interrupt disabled status of the demultiplexed subdevice
into account.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Trilok Soni <soni.trilok@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Brian Swetland <swetland@google.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: m.szyprowski@samsung.com
Cc: t.fujak@samsung.com
Cc: kyungmin.park@samsung.com,
Cc: David Brownell <david-b@pacbell.net>
Cc: Daniel Ribeiro <drwyrm@gmail.com>
Cc: arve@android.com
Cc: Barry Song <21cnbao@gmail.com>
Some interrupt chips are connected to a "slow" bus (i2c, spi ...). The
bus access needs to sleep and therefor cannot be called in atomic
contexts.
Some of the generic interrupt management functions like disable_irq(),
enable_irq() ... call interrupt chip functions with the irq_desc->lock
held and interrupts disabled. This does not work for such devices.
Provide a separate synchronization mechanism for such interrupt
chips. The irq_chip structure is extended by two optional functions
(bus_lock and bus_sync_and_unlock).
The idea is to serialize the bus access for those operations in the
core code so that drivers which are behind that bus operated interrupt
controller do not have to worry about it and just can use the normal
interfaces. To achieve this we add two function pointers to the
irq_chip: bus_lock and bus_sync_unlock.
bus_lock() is called to serialize access to the interrupt controller
bus.
Now the core code can issue chip->mask/unmask ... commands without
changing the fast path code at all. The chip implementation merily
stores that information in a chip private data structure and
returns. No bus interaction as these functions are called from atomic
context.
After that bus_sync_unlock() is called outside the atomic context. Now
the chip implementation issues the bus commands, waits for completion
and unlocks the interrupt controller bus.
The irq_chip implementation as pseudo code:
struct irq_chip_data {
struct mutex mutex;
unsigned int irq_offset;
unsigned long mask;
unsigned long mask_status;
}
static void bus_lock(unsigned int irq)
{
struct irq_chip_data *data = get_irq_desc_chip_data(irq);
mutex_lock(&data->mutex);
}
static void mask(unsigned int irq)
{
struct irq_chip_data *data = get_irq_desc_chip_data(irq);
irq -= data->irq_offset;
data->mask |= (1 << irq);
}
static void unmask(unsigned int irq)
{
struct irq_chip_data *data = get_irq_desc_chip_data(irq);
irq -= data->irq_offset;
data->mask &= ~(1 << irq);
}
static void bus_sync_unlock(unsigned int irq)
{
struct irq_chip_data *data = get_irq_desc_chip_data(irq);
if (data->mask != data->mask_status) {
do_bus_magic_to_set_mask(data->mask);
data->mask_status = data->mask;
}
mutex_unlock(&data->mutex);
}
The device drivers can use request_threaded_irq, free_irq, disable_irq
and enable_irq as usual with the only restriction that the calls need
to come from non atomic context.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Trilok Soni <soni.trilok@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Brian Swetland <swetland@google.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: m.szyprowski@samsung.com
Cc: t.fujak@samsung.com
Cc: kyungmin.park@samsung.com,
Cc: David Brownell <david-b@pacbell.net>
Cc: Daniel Ribeiro <drwyrm@gmail.com>
Cc: arve@android.com
Cc: Barry Song <21cnbao@gmail.com>
For threaded interrupt handlers we expect the hard interrupt handler
part to mask the interrupt on the originating device. The interrupt
line itself is reenabled after the hard interrupt handler has
executed.
This requires access to the originating device from hard interrupt
context which is not always possible. There are devices which can only
be accessed via a bus (i2c, spi, ...). The bus access requires thread
context. For such devices we need to keep the interrupt line masked
until the threaded handler has executed.
Add a new flag IRQF_ONESHOT which allows drivers to request that the
interrupt is not unmasked after the hard interrupt context handler has
been executed and the thread has been woken. The interrupt line is
unmasked after the thread handler function has been executed.
Note that for now IRQF_ONESHOT cannot be used with IRQF_SHARED to
avoid complex accounting mechanisms.
For oneshot interrupts the primary handler simply returns
IRQ_WAKE_THREAD and does nothing else. A generic implementation
irq_default_primary_handler() is provided to avoid useless copies all
over the place. It is automatically installed when
request_threaded_irq() is called with handler=NULL and
thread_fn!=NULL.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Trilok Soni <soni.trilok@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Brian Swetland <swetland@google.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: m.szyprowski@samsung.com
Cc: t.fujak@samsung.com
Cc: kyungmin.park@samsung.com,
Cc: David Brownell <david-b@pacbell.net>
Cc: Daniel Ribeiro <drwyrm@gmail.com>
Cc: arve@android.com
Cc: Barry Song <21cnbao@gmail.com>
free_irq() can remove an irqaction while the corresponding interrupt
is in progress, but free_irq() sets action->thread to NULL
unconditionally, which might lead to a NULL pointer dereference in
handle_IRQ_event() when the hard interrupt context tries to wake up
the handler thread.
Prevent this by moving the thread stop after synchronize_irq(). No
need to set action->thread to NULL either as action is going to be
freed anyway.
This fixes a boot crash reported against preempt-rt which uses the
mainline irq threads code to implement full irq threading.
[ tglx: removed local irqthread variable ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This takes care of the following entry from Dan's list:
kernel/irq/resend.c +73 check_irq_resend(17) warning: variable derefenced before check 'desc->chip'
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Eugene Teo <eteo@redhat.com>
Cc: Julia Lawall <julia@diku.dk>
LKML-Reference: <200908062146.03638.bzolnier@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Don't move it if target node is -1.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4A785B5D.4070702@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
