Following recent (and less so) issues with the 8254 timer when routed
through the I/O or local APIC, always report which configurations have
been tried and which one has been set up eventually. This is so that logs
posted by people for some other reason can be used as a cross-reference
when investigating any possible future problems.
The change unifies messages printed on 32-bit and 64-bit platforms and
adds trailing newlines (removes leading ones), so that proper log level
annotation can be used and any possible interspersed output will not cause
a mess.
I have chosen to use apic_printk(APIC_QUIET, ...) rather than printk(...)
so that the distinction of these messages is maintained making possible
future decisions about changes in this area easier. A change posted
separately making apic_verbosity unsigned removes any extra code that
would otherwise be generated as a result of this design decision.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Include <asm/i8259.h> for i8259A_lock used in print_PIC() -- #if-0-ed out
by default. The 32-bit version gets it right already.
The plan is to enable this code with "apic=debug" eventually. This will
aid with debugging strange problems without the need to ask people to
apply patches.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that IRQ2 is never made available to the I/O APIC, there is no need
to special-case it and mask as a workaround for broken systems. Actually,
because of the former, mask_IO_APIC_irq(2) is a no-op already.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no such entity as ISA IRQ2. The ACPI spec does not make it
explicitly clear, but does not preclude it either -- all it says is ISA
legacy interrupts are identity mapped by default (subject to overrides),
but it does not state whether IRQ2 exists or not. As a result if there is
no IRQ0 override, then IRQ2 is normally initialised as an ISA interrupt,
which implies an edge-triggered line, which is unmasked by default as this
is what we do for edge-triggered I/O APIC interrupts so as not to miss an
edge.
To the best of my knowledge it is useless, as IRQ2 has not been in use
since the PC/AT as back then it was taken by the 8259A cascade interrupt
to the slave, with the line position in the slot rerouted to newly-created
IRQ9. No device could thus make use of this line with the pair of 8259A
chips. Now in theory INTIN2 of the I/O APIC may be usable, but the
interrupt of the device wired to it would not be available in the PIC mode
at all, so I seriously doubt if anybody decided to reuse it for a regular
device.
However there are two common uses of INTIN2. One is for IRQ0, with an
ACPI interrupt override (or its equivalent in the MP table). But in this
case IRQ2 is gone entirely with INTIN0 left vacant. The other one is for
an 8959A ExtINTA cascade. In this case IRQ0 goes to INTIN0 and if ACPI is
used INTIN2 is assumed to be IRQ2 (there is no override and ACPI has no
way to report ExtINTA interrupts). This is where a problem happens.
The problem is INTIN2 is configured as a native APIC interrupt, with a
vector assigned and the mask cleared. And the line may indeed get active
and inject interrupts if the master 8959A has its timer interrupt enabled
(it might happen for other interrupts too, but they are normally masked in
the process of rerouting them to the I/O APIC). There are two cases where
it will happen:
* When the I/O APIC NMI watchdog is enabled. This is actually a misnomer
as the watchdog pulses are delivered through the 8259A to the LINT0
inputs of all the local APICs in the system. The implication is the
output of the master 8259A goes high and low repeatedly, signalling
interrupts to INTIN2 which is enabled too!
[The origin of the name is I think for a brief period during the
development we had a capability in our code to configure the watchdog to
use an I/O APIC input; that would be INTIN2 in this scenario.]
* When the native route of IRQ0 via INTIN0 fails for whatever reason -- as
it happens with the system considered here. In this scenario the timer
pulse is delivered through the 8259A to LINT0 input of the local APIC of
the bootstrap processor, quite similarly to how is done for the watchdog
described above. The result is, again, INTIN2 receives these pulses
too. Rafael's system used to escape this scenario, because an incorrect
IRQ0 override would occupy INTIN2 and prevent it from being unmasked.
My conclusion is IRQ2 should be excluded from configuration in all the
cases and the current exception for ACPI systems should be lifted. The
reason being the exception not only being useless, but harmful as well.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Unlike the 32-bit one, the 64-bit variation of the LVT0 setup code for
the "8259A Virtual Wire" through the local APIC timer configuration does
not fully configure the relevant irq_chip structure. Instead it relies on
the preceding I/O APIC code to have set it up, which does not happen if
the I/O APIC variants have not been tried.
The patch includes corresponding changes to the 32-bit variation too
which make them both the same, barring a small syntactic difference
involving sequence of functions in the source. That should work as an aid
with the upcoming merge.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When an interrupt is rerouted to a different I/O APIC pin the relevant
entry of the irq_2_pin list should get updated accordingly so that
operations are performed on the correct redirection entry.
This is already done by the 32-bit variation of the code and here is a
complementing 64-bit implementation. Should make someone's decision less
tough when merging the two. ;)
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This reverts commit 90221a61a71b7ad659d8741cf1e404506b174982.
This too was just temporary diagnostics - not needed now that we've
got the final fix via:
| commit e2079c4386
| Author: Rafael J. Wysocki <rjw@sisk.pl>
| Date: Tue Jul 8 16:12:26 2008 +0200
|
| x86: fix C1E && nx6325 stability problem
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This reverts commit a74a1cc3df0be89658bc735c8aed80c8392e2c15.
This was just temporary diagnostics commit - not needed now that we've
got the final fix.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The problems are that, with the ACPI vs timer overring issue _fixed_,
after using the box for some time (between several seconds and 1 hour, at
random) processes get very high CPU loads (once I've got X using 107% of
the CPU, for example) and the system becomes unresponsive, as though there
were interrupts lost or something similar.
Andreas Herrman reproduced similar problems:
> Ok, now I've reproduced the stability problem.
> - Using tip/master,
> - reverting e38502eb8aa82314d5ab0eba45f50e6790dadd88 and
> - applying your patch from this posting
> http://marc.info/?l=linux-kernel&m=121539354224562&w=4
>
> Starting X, firefox, gimp, tuxpaint and doing some drawing in tuxpaint
> results in a slow system. Drawing is almost not possible anymore --
> Selections of new colors, cursors etc. is performed with huge delay
> if it's performed at all.
>
> BTW, the code sets up timer IRQ as Virtual Wire IRQ:
>
> Jul 8 14:57:58 kodscha IO-APIC (apicid-pin) 2-22, 2-23 not connected.
> Jul 8 14:57:58 kodscha ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> Jul 8 14:57:58 kodscha ...trying to set up timer as Virtual Wire IRQ... works.
>
> and both INT0 and INT2 of IOAPIC are masked:
>
> Jul 8 14:57:58 kodscha NR Dst Mask Trig IRR Pol Stat Dmod Deli Vect:
> Jul 8 14:57:58 kodscha 00 000 1 0 0 0 0 0 0 00
> Jul 8 14:57:58 kodscha 01 003 0 0 0 0 0 1 1 31
> Jul 8 14:57:58 kodscha 02 003 1 0 0 0 0 0 0 30
>
> I've also seen strange CPU utilization -- with syslog-ng:
>
> top - 15:33:06 up 35 min, 4 users, load average: 1.70, 0.68, 0.37
> Tasks: 64 total, 4 running, 60 sleeping, 0 stopped, 0 zombie
> Cpu0 : 0.0%us,100.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> Cpu1 : 6.4%us, 87.2%sy, 0.0%ni, 5.8%id, 0.0%wa, 0.6%hi, 0.0%si, 0.0%st
> Mem: 895384k total, 283568k used, 611816k free, 35492k buffers
> Swap: 1959920k total, 0k used, 1959920k free, 163044k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 4632 root 20 0 17216 800 580 S 104 0.1 0:34.22 syslog-ng
> 28505 root 20 0 205m 11m 4024 S 6 1.3 0:21.16 X
> 28518 root 20 0 56292 5652 4492 S 1 0.6 0:01.80 fluxbox
> 1 root 20 0 3724 608 508 S 0 0.1 0:00.36 init
>
> So far I have no clue why C1E-idle in conjunction with virtual wire
> mode causes this strange behaviour.
>
> ... and I start to think about the root cause of all this.
>
> I've performed similar tests under X with the IRQ0/INT0 configuration and
> I did not see above symptoms.
So lets fall back to the IRQ0/INT0 configuration on this box.
This basically restores the dont-use-the-lapic-timer exception mechanism
that was unconditional on this box prior commit 8750bf5 ("x86: add C1E
aware idle function").
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no need to keep NMI_DISABLED definition and use it
for nmi_watchdog by default. Here is the point why:
- IO-APIC and APIC chips are programmed for nmi_watchdog support at very
early stage of kernel booting and not having nmi_watchdog specified as
boot option lead only to nmi_watchdog becomes to NMI_NONE anyway
- enable nmi_watchdog thru /proc/sys/kernel/nmi if it was not specified at
boot is not possible too (even having this sysfs entry)
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: macro@linux-mips.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We create a version of it for i386, and then take the CONFIG_X86_64
ifdef out of the game. We could create a __setup_vector_irq for i386,
but it would incur in an unnecessary lock taking. Moreover, it is better
practice to only export setup_vector_irq anyway.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
> That helped a lot, the system seems to work normally now.
>
> Here's the relevant snippet from dmesg:
>
> [ 0.108006] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> [ 0.108006] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
> [ 0.108006] ...trying to set up timer (IRQ0) through the 8259A ... <3>
> [ 0.108006] ..... (found apic 0 pin 2) ...<3> failed.
> [ 0.108006] ...trying to set up timer as Virtual Wire IRQ...<3> works.
>
> and the whole thing is at: http://www.sisk.pl/kernel/debug/20080618/dmesg-2.log
Hmm, that only proved the 8259A is indeed wired to the pin #2 of the I/O
APIC.
> I, personally, don't have any and AMD only has SB600 documentation on its
> web page (it's still marked as "AMD confidential" ;-)).
Well, the IC block is most likely the same as that's not rocket science
and once done there is no need to fiddle with that. That written, I am
afraid there is nothing useful about the IC in the document, except that
it's there and consists of an I/O APIC providing 24 inputs and the usual
pair of 8259A cores. Thanks for the reference anyway.
> There is an interrupt controller in there, but I'm not sure if there's any
> 8259A. The northbridge is on the CPU, actually.
I will praise the day someone ships an x86 machine without an 8259A core!
As expressed in another mail I suspect there may actually be a direct
route from the 8254 to INTIN0 in the southbridge -- this is what other
bootstrap logs seen in the Internet suggest. This would mean this
particular BIOS is buggy (is it the latest version?) and provides an
incorrect IRQ override in its ACPI tables, for example because the
responsible block has been blindly copied from a machine using a commoner
wiring. This could be moderately easily fixed up with a quirk based on
the PCI ID (after checking it again, we actually used to have a quirk for
ATI in this area, but the way it was done suggests the issue was not
understood well enough).
Could you please remove the hack sent yesterday and test the patch
provided below? I do hope it builds, but I have no immediate means to
check it. Please report the output. The intent is to test INTIN0
directly before testing INTIN2 through the 8259A. Thanks.
Aside of that, what I have gathered from your reports (please correct me
if I have got it wrong) is that when the through-8259A mode is used, then
after a while 8254 timer interrupts stop arriving. What's interesting,
the "Virtual Wire IRQ" seems to work for you correctly (that's quite an
odd setup where a local APIC input is used in the native mode -- please
post /proc/interrupts for confirmation), which in turn implies the master
8259A drives its INT output as we expect. Why would the I/O APIC input
have problems then? Hmm...
[ mingo@elte.hu: revert the "x86: fix IO APIC breakage on HP nx6325"
version. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On Thu, 19 Jun 2008, Rafael J. Wysocki wrote:
> > With such a configuration the "x86: I/O APIC: timer through 8259A
> > second-chance" patch should not matter, because the only change it
> > introduces is an attempt to try the same I/O APIC pin again, but with the
> > IRQ0 line of the master 8259A enabled. That's not a terribly unusual
> > configuration and nothing should get confused in the system.
>
> But it _does_ get confused, really.
Something certainly gets confused, but so far I am not sure which bit
exactly it is, are you?
> > Barring the unlikely possibility of the 8259A actually being wired to
> > INTIN2 of the I/O APIC I can see two possible explanations:
> >
> > 1. The 8259A interrupt actually escapes to the CPU somehow and is handled
> > as an ExtINTA interrupt. This would make the code in check_timer()
> > decide it has found a working configuration, while actually it has been
> > fooled.
[...]
> Here you go:
>
> [ 0.108006] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> [ 0.108006] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
> [ 0.108006] ...trying to set up timer (IRQ0) through the 8259A ... <3>
> [ 0.108006] ..... (found apic 0 pin 2) ...<3> works.
>
> The full dmesg is at: http://www.sisk.pl/kernel/debug/20080618/dmesg-1.log
Thanks. In this case I suspect the case #1 quoted above happens, that is
the 8259A manages to deliver its interrupt somehow. Note at this stage it
is meant to be in the AEOI mode, so it can happily resubmit the interrupt
indefinitely with no additional handling as long as it receives INTA
cycles.
Can you please try the patch below on top of "x86: I/O APIC: timer
through 8259A second-chance" to see whether my hypothesis is true? It
modifies the through-8259A setup path so that the APIC input gets masked,
but the 8259A has the timer interrupt still enabled. Let me know how the
timer interrupt is routed in this case.
Bisected-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Not sure but maybe it is better to use NMI_DISABLED,
will take a look. But for now this patch is not change
anything in logic so it will not hurt/broke the kernel.
For most cases nmi_watchdog assignment is by one of NMI_*
macro so I think there it make sense too.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/io_apic_64.c: In function 'check_timer':
arch/x86/kernel/io_apic_64.c:1688: error: 'vector' undeclared (first use in this function)
arch/x86/kernel/io_apic_64.c:1688: error: (Each undeclared identifier is reported only once
arch/x86/kernel/io_apic_64.c:1688: error: for each function it appears in.)
Some systems incorrectly report the ExtINTA pin of the I/O APIC as the
genuine target of the timer interrupt. Here is a change that copies timer
pin information found to the other pin if one has been found only. This
way both a direct and a through-8259A route is tested with the pin letting
these problematic systems work well enough. If no timer pin information
has been found for the I/O APIC, then local APIC variations are tried
only, similarly to what is done without the change (except without the
misleading messages).
Obviously if we try the first-chance path without being told by the BIOS
to do so, we should not complain either, so do not print the message in
this case.
The 64-bit variation should be updated with a call to
replace_pin_at_irq() which can be done with the upcoming merge. Since
add_pin_to_irq() is now always called in the first-chance path, the
condition to require it in the second-chance path no longer happens.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Keep the timer interrupt line masked when reconfiguring its interrupt
redirection entry in the I/O APIC.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Unmask the timer interrupt line set up in the through-8259A mode
explicitly after setup_timer_IRQ0_pin() has set up the I/O APIC interrupt
redirection entry to let the two operations be unbound from each other.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Rename setup_ExtINT_IRQ0_pin() to setup_timer_IRQ0_pin() to better
reflect the upcoming role of a function setting up a (semi-)arbitrary I/O
APIC pin appropriately for the 8254 timer. By "appropriate" the following
settings are meant: edge-triggered, active-high, all the other settings
per-architecture. Adjust comments to reflect code appropriately. No
functional changes.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The LINT0 line of the local APIC is masked in the LVT0 entry in
check_timer() before this function is ever called. Removed the
redundant unmasking for better control.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For a better control the masking and unmasking of the timer interrupt
line in the 8259A operating in the 'Virtual Wire' mode has been moved out
of setup_ExtINT_IRQ0_pin() now, so remove the redundant calls from the
function.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no point in keeping the 8259A enabled if the I/O APIC NMI
watchdog has failed and the 8259A is not used to pass through regular
timer interrupts. This fixes problems with some systems where some logic
gets confused.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Disable the 8259A acting in the "virtual wire" mode to keep the interrupt
line inactive while fiddling with local APIC interrupt vector registers
associated with its destination inputs. To be on the safe side,
especially concerning flipping the trigger mode.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Disable the 8259A when routing of the timer interrupt through the chip to
the local APIC of the primary processor has failed.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the "disable_8254_timer" and "enable_8254_timer" kernel
parameters. Now that AEOI acknowledgements are no longer needed for
correct timer operation, the 8259A can be kept disabled unconditionally
unless interrupts, either timer or watchdog ones, are actually passed
through it.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The code that used to be in do_slow_gettimeoffset() that relied on the
IRR bit of the master 8259A PIC for IRQ0 to check the state of the output
timer 0 of the PIT is no longer there. As a result, there is no need to
use the POLL command to acknowledge the timer interrupt in the "8259A
Virtual Wire", except for the NMI watchdog when the i82489DX APIC is used
(this is because this particular APIC treats NMIs as level-triggered and
keeping the input asserted would keep motherboard NMI sources held off for
too long). Remove the unneeded bits and adjust comments accordingly.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The SGI UV system needs several more system vectors than a vanilla
x86_64 system. Rather than burden the other archs with extra system
vectors that they don't use, change FIRST_SYSTEM_VECTOR to a variable,
so that it can be dynamic.
Signed-off-by: Alan Mayer <ajm@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch fixes section mismatch warnings in unlock_ExtINT_logic().
WARNING: arch/x86/kernel/built-in.o(.text+0x14a92): Section mismatch in reference from the function unlock_ExtINT_logic()
to the function .init.text:find_isa_irq_pin()
The function unlock_ExtINT_logic() references
the function __init find_isa_irq_pin().
This is often because unlock_ExtINT_logic lacks a __init
annotation or the annotation of find_isa_irq_pin is wrong.
Signed-off-by: Jacek Luczak <luczak.jacek@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Replace usages of CPU_MASK_NONE, CPU_MASK_ALL, NODE_MASK_NONE,
NODE_MASK_ALL to reduce stack requirements for large NR_CPUS
and MAXNODES counts.
* In some cases, the cpumask variable was initialized but then overwritten
with another value. This is the case for changes like this:
- cpumask_t oldmask = CPU_MASK_ALL;
+ cpumask_t oldmask;
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use cpumask_of_cpu() rather than the pair of cpus_clear() and cpu_set().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
No need to clear the memory allocated by alloc_bootmem().
It is already filled with zero.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove duplicate code by using ioapic_read_entry() and ioapic_write_entry()
in io_apic_{32,64}.c
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If one can find an ack pending pin, there is no need to check
the rest of them.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce a function to read the local APIC_ID.
This change is in preparation for additional changes to
the APICID functions that will come in a later patch.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
