Currently we handle spurious IRQ activity based upon seeing a lot of
invalid interrupts, and we clear things back on the base of lots of valid
interrupts.
Unfortunately in some cases you get legitimate invalid interrupts caused by
timing asynchronicity between the PCI bus and the APIC bus when disabling
interrupts and pulling other tricks. In this case although the spurious
IRQs are not a problem our unhandled counters didn't clear and they act as
a slow running timebomb. (This is effectively what the serial port/tty
problem that was fixed by clearing counters when registering a handler
showed up)
It's easy enough to add a second parameter - time. This means that if we
see a regular stream of harmless spurious interrupts which are not harming
processing we don't go off and do something stupid like disable the IRQ
after a month of running. OTOH lockups and performance killers show up a
lot more than 10/second
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With irqpoll enabled, trying to test the IRQF_IRQPOLL flag in the
actions would cause a NULL pointer dereference if no action was
installed (for example, the driver might have been unloaded with
interrupts still pending).
So be a bit more careful about testing the flag by making sure to test
for that case.
(The actual _change_ is trivial, the patch is more than a one-liner
because I rewrote the testing to also be much more readable.
Original (discarded) bugfix by Bernhard Walle.
Cc: Bernhard Walle <bwalle@suse.de>
Tested-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On SN, only allow one bit to be set in the smp_affinty mask when
redirecting an interrupt. Currently setting multiple bits is allowed, but
only the first bit is used in determining the CPU to redirect to. This has
caused confusion among some customers.
[akpm@linux-foundation.org: fixes]
Signed-off-by: John Keller <jpk@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
A linuxdoc comment had fallen out of date - it refers to an argument which no
longer exists.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
irqpoll is broken on some architectures that don't use the IRQ 0 for the timer
interrupt like IA64. This patch adds a IRQF_IRQPOLL flag.
Each architecture is handled in a separate pach. As I left the irq == 0 as
condition, this should not break existing architectures that use timer_irq ==
0 and that I did't address with that patch (because I don't know).
This patch:
This patch adds a IRQF_IRQPOLL flag that the interrupt registration code could
use for the interrupt it wants to use for IRQ polling.
Because this must not be the timer interrupt, an additional flag was added
instead of re-using the IRQF_TIMER constant. Until all architectures will
have an IRQF_IRQPOLL interrupt, irq == 0 will stay as alternative as it should
not break anything.
Also, note_interrupt() is called on CPU-specific interrupts to be used as
interrupt source for IRQ polling.
Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Grant Grundler <grundler@google.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We noticed a drop in n/w performance due to the irq_desc being cacheline
aligned rather than internode aligned. We see 50% of expected performance
when two e1000 nics local to two different nodes have consecutive irq
descriptors allocated, due to false sharing.
Note that this patch does away with cacheline padding for the UP case, as
it does not seem useful for UP configurations.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
An irqaction structure won't be added to an IRQ descriptor irqaction list if
it doesn't agree with other irqactions on the IRQF_PERCPU flag. Don't check
for this flag to change IRQ descriptor `status' for every irqaction added to
the list, Doing the check only for the first irqaction added is enough.
Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
setup_irq() releases a desc->lock before calling register_handler_proc(), so
the iteration over the IRQ action list is not protected.
(akpm: the check itself is still racy, but at least it probably won't oops
now).
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
set_irq_msi() currently connects an irq_desc to an msi_desc. The archs call
it at some point in their setup routine, and then the generic code sets up the
reverse mapping from the msi_desc back to the irq.
set_irq_msi() should do both connections, making it the one and only call
required to connect an irq with it's MSI desc and vice versa.
The arch code MUST call set_irq_msi(), and it must do so only once it's sure
it's not going to fail the irq allocation.
Given that there's no need for the arch to return the irq anymore, the return
value from the arch setup routine just becomes 0 for success and anything else
for failure.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
devres should be deallocated with devres_free() not kfree(). This bug
corrupts slab on IRQ request failure. Fix it.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
move_native_irqs tries to do the right thing when migrating irqs
by disabling them. However disabling them is a software logical
thing, not a hardware thing. This has always been a little flaky
and after Ingo's latest round of changes it is guaranteed to not
mask the apic.
So this patch fixes move_native_irq to directly call the mask and
unmask chip methods to guarantee that we mask the irq when we
are migrating it. We must do this as it is required by
all code that call into the path.
Since we don't know the masked status when IRQ_DISABLED is
set so we will not be able to restore it. The patch makes the code
just give up and trying again the next time this routing is called.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use mask_ack_irq() where possible.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Never mask interrupts immediately upon request. Disabling interrupts in
high-performance codepaths is rare, and on the other hand this change could
recover lost edges (or even other types of lost interrupts) by conservatively
only masking interrupts after they happen. (NOTE: with this change the
highlevel irq-disable code still soft-disables this IRQ line - and if such an
interrupt happens then the IRQ flow handler keeps the IRQ masked.)
Mark i8529A controllers as 'never loses an edge'.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide funtions to:
- check, whether an interrupt can set the affinity
- pin the interrupt to a given cpu
Necessary for the ability to setup clocksources more flexible (e.g. use the
different HPET channels per CPU)
[akpm@osdl.org: alpha build fix]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a flag so we can prevent the irq balancing of an interrupt. Move the
bits, so we have room for more :)
Necessary for the ability to setup clocksources more flexible (e.g. use the
different HPET channels per CPU)
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The problem is various drivers legally validly and sensibly try to claim
IRQs but the kernel insists on vomiting forth a giant irrelevant debugging
spew when the types clash.
Edit kernel/irq/manage.c go down to mismatch: in setup_irq() and ifdef out
the if clause that checks for mismatches. It'll then just do the right
thing and work sanely.
For the current -mm kernel this will do the trick (and moves it into shared
irq debugging as in debug mode the info spew is useful). I've had a
variant of this in my private tree for some time as I got fed up on the
mess on boxes where old legacy IRQs get reused.
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Drivers registering IRQ handlers with SA_SHIRQ really ought to be able to
handle an interrupt happening before request_irq() returns. They also
ought to be able to handle an interrupt happening during the start of their
call to free_irq(). Let's test that hypothesis....
[bunk@stusta.de: Kconfig fixes]
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Split the implementation-agnostic stuff in separate files.
* Make sure that targets using non-default request_irq() pull
kernel/irq/devres.o
* Introduce new symbols (HAS_IOPORT and HAS_IOMEM) defaulting to positive;
allow architectures to turn them off (we needed these symbols anyway for
dependencies of quite a few drivers).
* protect the ioport-related parts of lib/devres.o with CONFIG_HAS_IOPORT.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bug: pnx8550 code creates directory but resets ->nlink to 1.
create_proc_entry() et al will correctly set ->nlink for you.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement device resource management, in short, devres. A device
driver can allocate arbirary size of devres data which is associated
with a release function. On driver detach, release function is
invoked on the devres data, then, devres data is freed.
devreses are typed by associated release functions. Some devreses are
better represented by single instance of the type while others need
multiple instances sharing the same release function. Both usages are
supported.
devreses can be grouped using devres group such that a device driver
can easily release acquired resources halfway through initialization
or selectively release resources (e.g. resources for port 1 out of 4
ports).
This patch adds devres core including documentation and the following
managed interfaces.
* alloc/free : devm_kzalloc(), devm_kzfree()
* IO region : devm_request_region(), devm_release_region()
* IRQ : devm_request_irq(), devm_free_irq()
* DMA : dmam_alloc_coherent(), dmam_free_coherent(),
dmam_declare_coherent_memory(), dmam_pool_create(),
dmam_pool_destroy()
* PCI : pcim_enable_device(), pcim_pin_device(), pci_is_managed()
* iomap : devm_ioport_map(), devm_ioport_unmap(), devm_ioremap(),
devm_ioremap_nocache(), devm_iounmap(), pcim_iomap_table(),
pcim_iomap(), pcim_iounmap()
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
We need to be able to get from an irq number to a struct msi_desc.
The msi_desc array in msi.c had several short comings the big one was
that it could not be used outside of msi.c. Using irq_data in struct
irq_desc almost worked except on some architectures irq_data needs to
be used for something else.
So this patch adds a msi_desc pointer to irq_desc, adds the appropriate
wrappers and changes all of the msi code to use them.
The dynamic_irq_init/cleanup code was tweaked to ensure the new
field is left in a well defined state.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Any newly added irq handler may obviously make any old spurious irq
status invalid, since the new handler may well be the thing that is
supposed to handle any interrupts that came in.
So just clear the statistics when adding handlers.
Pointed-out-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
o noirqdebug_setup() is __init but it is being called by
quirk_intel_irqbalance() which if of type __devinit. If CONFIG_HOTPLUG=y,
quirk_intel_irqbalance() is put into text section and it is wrong to
call a function in __init section.
o MODPOST flags this on i386 if CONFIG_RELOCATABLE=y
WARNING: vmlinux - Section mismatch: reference to .init.text:noirqdebug_setup from .text between 'quirk_intel_irqbalance' (at offset 0xc010969e) and 'i8237A_suspend'
o Make noirqdebug_setup() non-init.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
The sanity check for no_irq_chip in __set_irq_hander() is unconditional on
both install and uninstall of an handler. This triggers false warnings and
replaces no_irq_chip by dummy_irq_chip in the uninstall case.
Check only, when a real handler is installed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Sylvain Munaut <tnt@246tNt.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
While running my MCA test (hardware error injection) on 2.6.19,
I got some warning like following:
> BUG: warning at kernel/irq/migration.c:27/move_masked_irq()
>
> Call Trace:
> [<a000000100013d20>] show_stack+0x40/0xa0
> sp=e00000006b2578d0 bsp=e00000006b2510b0
> [<a000000100013db0>] dump_stack+0x30/0x60
> sp=e00000006b257aa0 bsp=e00000006b251098
> [<a0000001000de430>] move_masked_irq+0xb0/0x240
> sp=e00000006b257aa0 bsp=e00000006b251070
> [<a0000001000de6a0>] move_native_irq+0xe0/0x180
> sp=e00000006b257aa0 bsp=e00000006b251040
> [<a00000010004ff50>] iosapic_end_level_irq+0x30/0xe0
> sp=e00000006b257aa0 bsp=e00000006b251020
> [<a0000001000d94d0>] __do_IRQ+0x170/0x400
> sp=e00000006b257aa0 bsp=e00000006b250fd8
> [<a0000001000116f0>] ia64_handle_irq+0x1b0/0x260
> sp=e00000006b257aa0 bsp=e00000006b250fa8
> [<a00000010000c3a0>] ia64_leave_kernel+0x0/0x280
> sp=e00000006b257aa0 bsp=e00000006b250fa8
> [<a000000100690cf0>] _spin_unlock_irqrestore+0x30/0x60
> sp=e00000006b257c70 bsp=e00000006b250f90
It comes from:
[kernel/irq/migration.c]
26 if (CHECK_IRQ_PER_CPU(desc->status)) {
27 WARN_ON(1);
28 return;
29 }
By putting some printk in kernel, I found that irqbalance is trying to
move CPEI which is handled as PER_CPU irq. That's why.
CPEI(Corrected Platform Error Interrupt) is ia64 specific irq, is
allowed to pin to particular processor which selected by the platform, and
even it is PER_CPU but it has set_affinity handler (=iosapic_set_affinity)
as same as other IO-SAPIC-level interrupts. (I don't know why, but
I guess that there would be typical situation where the handler for
migration is needed, such as hotplug - the processor going to be
offline/hot-removed.)
To shut up this warning, there are 2 way at least:
a) fix CPEI stuff
b) prohibit setting affinity to PER_CPU irq
I'm not sure what stuff of CPEI need to be fixed, but I think that
returning error to attempting move PER_CPU irq is useful for all
applications since it will never work.
Following small patch takes b) style.
It works, the warning disappeared and irqbalance still runs well.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Name some of the remaning 'old_style_spin_init' locks
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This reverts commit f72fa70760, and solves
the problem that it tried to fix by simply making "__do_IRQ()" call the
note_interrupt() function without the lock held, the way everybody else
does.
It should be noted that all interrupt handling code must never allow the
descriptor actors to be entered "recursively" (that's why we do all the
magic IRQ_PENDING stuff in the first place), so there actually is
exclusion at that much higher level, even in the absense of locking.
Acked-by: Vivek Goyal <vgoyal@in.ibm.com>
Acked-by:Pavel Emelianov <xemul@openvz.org>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When we get a mismatch between handlers on the same IRQ, all we get is "IRQ
handler type mismatch for IRQ n". Let's print the name of the
presently-registered handler with which we got the mismatch.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
While testing kernel on machine with "irqpoll" option I've caught such a
lockup:
__do_IRQ()
spin_lock(&desc->lock);
desc->chip->ack(); /* IRQ is ACKed */
note_interrupt()
misrouted_irq()
handle_IRQ_event()
if (...)
local_irq_enable_in_hardirq();
/* interrupts are enabled from now */
...
__do_IRQ() /* same IRQ we've started from */
spin_lock(&desc->lock); /* LOCKUP */
Looking at misrouted_irq() code I've found that a potential deadlock like
this can also take place:
1CPU:
__do_IRQ()
spin_lock(&desc->lock); /* irq = A */
misrouted_irq()
for (i = 1; i < NR_IRQS; i++) {
spin_lock(&desc->lock); /* irq = B */
if (desc->status & IRQ_INPROGRESS) {
2CPU:
__do_IRQ()
spin_lock(&desc->lock); /* irq = B */
misrouted_irq()
for (i = 1; i < NR_IRQS; i++) {
spin_lock(&desc->lock); /* irq = A */
if (desc->status & IRQ_INPROGRESS) {
As the second lock on both CPUs is taken before checking that this irq is
being handled in another processor this may cause a deadlock. This issue
is only theoretical.
I propose the attached patch to fix booth problems: when trying to handle
misrouted IRQ active desc->lock may be unlocked.
Acked-by: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Introduce desc->name and eliminate the handle_irq_name() hack. Add
set_irq_chip_and_handler_name() to set the flow type and name at once.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
lib/bitmap.c:bitmap_parse() is a library function that received as input a
user buffer. This seemed to have originated from the way the write_proc
function of the /proc filesystem operates.
This has been reworked to not use kmalloc and eliminates a lot of
get_user() overhead by performing one access_ok before using __get_user().
We need to test if we are in kernel or user space (is_user) and access the
buffer differently. We cannot use __get_user() to access kernel addresses
in all cases, for example in architectures with separate address space for
kernel and user.
This function will be useful for other uses as well; for example, taking
input for /sysfs instead of /proc, so it was changed to accept kernel
buffers. We have this use for the Linux UWB project, as part as the
upcoming bandwidth allocator code.
Only a few routines used this function and they were changed too.
Signed-off-by: Reinette Chatre <reinette.chatre@linux.intel.com>
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Joe Korty <joe.korty@ccur.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With the following patch, the ixp4xxdefconfig builds correctly. I'll
test some more configs if I get some time.
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
Typedef the IRQ handler function type.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1356d1e5fd256997e3d3dce0777ab787d0515c7a commit)
Typedef the IRQ flow handler function type.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 8e973fbdf5716b93a0a8c0365be33a31ca0fa351 commit)
Currently msi.c is doing sanity checks that make certain before an irq is
destroyed it has no more users.
By adding irq_has_action I can perform the test is a generic way, instead of
relying on a msi specific data structure.
By performing the core check in dynamic_irq_cleanup I ensure every user of
dynamic irqs has a test present and we don't free resources that are in use.
In msi.c this allows me to kill the attrib.state member of msi_desc and all of
the assciated code to maintain it.
To keep from freeing data structures when irq cleanup code is called to soon
changing dyanamic_irq_cleanup is insufficient because there are msi specific
data structures that are also not safe to free.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With the msi support comes a new concept in irq handling, irqs that are
created dynamically at run time.
Currently the msi code allocates irqs backwards. First it allocates a
platform dependent routing value for an interrupt the ``vector'' and then it
figures out from the vector which irq you are on.
This msi backwards allocator suffers from two basic problems. The allocator
suffers because it is trying to do something that is architecture specific in
a generic way making it brittle, inflexible, and tied to tightly to the
architecture implementation. The alloctor also suffers from it's very
backwards nature as it has tied things together that should have no
dependencies.
To solve the basic dynamic irq allocation problem two new architecture
specific functions are added: create_irq and destroy_irq.
create_irq takes no input and returns an unused irq number, that won't be
reused until it is returned to the free poll with destroy_irq. The irq then
can be used for any purpose although the only initial consumer is the msi
code.
destroy_irq takes an irq number allocated with create_irq and returns it to
the free pool.
Making this functionality per architecture increases the simplicity of the irq
allocation code and increases it's flexibility.
dynamic_irq_init() and dynamic_irq_cleanup() are added to automate the
irq_desc initializtion that should happen for dynamic irqs.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently move_native_irq disables and renables the irq we are migrating to
ensure we don't take that irq when we are actually doing the migration
operation. Disabling the irq needs to happen but sometimes doing the work is
move_native_irq is too late.
On x86 with ioapics the irq move sequences needs to be:
edge_triggered:
mask irq.
move irq.
unmask irq.
ack irq.
level_triggered:
mask irq.
ack irq.
move irq.
unmask irq.
We can easily perform the edge triggered sequence, with the current defintion
of move_native_irq. However the level triggered case does not map well. For
that I have added move_masked_irq, to allow me to disable the irqs around both
the ack and the move.
Q: Why have we not seen this problem earlier?
A: The only symptom I have been able to reproduce is that if we change
the vector before acknowleding an irq the wrong irq is acknowledged.
Since we currently are not reprogramming the irq vector during
migration no problems show up.
We have to mask the irq before we acknowledge the irq or else we could
hit a window where an irq is asserted just before we acknowledge it.
Edge triggered irqs do not have this problem because acknowledgements
do not propogate in the same way.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The primary aim of this patchset is to remove maintenances problems caused by
the irq infrastructure. The two big issues I address are an artificially
small cap on the number of irqs, and that MSI assumes vector == irq. My
primary focus is on x86_64 but I have touched other architectures where
necessary to keep them from breaking.
- To increase the number of irqs I modify the code to look at the (cpu,
vector) pair instead of just looking at the vector.
With a large number of irqs available systems with a large irq count no
longer need to compress their irq numbers to fit. Removing a lot of brittle
special cases.
For acpi guys the result is that irq == gsi.
- Addressing the fact that MSI assumes irq == vector takes a few more
patches. But suffice it to say when I am done none of the generic irq code
even knows what a vector is.
In quick testing on a large Unisys x86_64 machine we stumbled over at least
one driver that assumed that NR_IRQS could always fit into an 8 bit number.
This driver is clearly buggy today. But this has become a class of bugs that
it is now much easier to hit.
This patch:
This is a minor space optimization. In practice I don't think this has any
affect because of our alignment constraints and the other fields but there is
not point in chewing up an uncessary word and since we already read the flag
field this should improve the cache hit ratio of the irq handler.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Permit __do_IRQ() to be dispensed with based on a configuration option.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
while porting the -rt tree to 2.6.18-rc7 i noticed the following
screaming-IRQ scenario on an SMP system:
2274 0Dn.:1 0.001ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.010ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.020ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.029ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.039ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.048ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.058ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.068ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.077ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.087ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
2274 0Dn.:1 0.097ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf)
as it turns out, the bug is caused by handle_level_irq(), which if it
races with another CPU already handling this IRQ, it _unmasks_ the IRQ
line on the way out. This is not how 2.6.17 works, and we introduced
this bug in one of the early genirq cleanups right before it went into
-mm. (the bug was not in the genirq patchset for a long time, and we
didnt notice the bug due to the lack of -rt rebase to the new genirq
code. -rt, and hardirq-preemption in particular opens up such races much
wider than anything else.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix a bug where the IRQ_PENDING flag is never cleared and the ISR is called
endlessly without an actual interrupt.
Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Adds the description of the parameters from handle_bad_irq().
Signed-off-by: Henrik Kretzschmar <henne@nachtwindheim.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
IRQs need refcounting and a state flag to track whether the the IRQ should
be enabled or disabled as a "normal IRQ" source after a series of calls to
{en,dis}able_irq(). For shared IRQs, the IRQ must be enabled so long as at
least one driver needs it active.
Likewise, IRQs need the same support to track whether the IRQ should be
enabled or disabled as a "wakeup event" source after a series of calls to
{en,dis}able_irq_wake(). For shared IRQs, the IRQ must be enabled as a
wakeup source during sleep so long as at least one driver needs it. But
right now they _don't have_ that refcounting ... which means sharing a
wakeup-capable IRQ can't work correctly in some configurations.
This patch adds the refcount and flag mechanisms to set_irq_wake() -- which
is what {en,dis}able_irq_wake() call -- and minimal documentation of what
the irq wake mechanism does.
Drivers relying on the older (broken) "toggle" semantics will trigger a
warning; that'll be a handful of drivers on ARM systems.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Alan Cox