Just convert all the files that have an nmi handler to the new routines.
Most of it is straight forward conversion.  A couple of places needed some
tweaking like kgdb which separates the debug notifier from the nmi handler
and mce removes a call to notify_die.

[Thanks to Ying for finding out the history behind that mce call

https://lkml.org/lkml/2010/5/27/114

And Boris responding that he would like to remove that call because of it

https://lkml.org/lkml/2011/9/21/163]

The things that get converted are the registeration/unregistration routines
and the nmi handler itself has its args changed along with code removal
to check which list it is on (most are on one NMI list except for kgdb
which has both an NMI routine and an NMI Unknown routine).
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NCorey Minyard <minyard@acm.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/1317409584-23662-4-git-send-email-dzickus@redhat.comSigned-off-by: NIngo Molnar <mingo@elte.hu>

Before the conversion of the NMI watchdog to perf event, the
watchdog timeout was 5 seconds. Now it is 60 seconds. For my
particular application, netbooks, 5 seconds was a better
timeout. With a short timeout, we catch faults earlier and are
able to send back a panic. With a 60 second timeout, the user is
unlikely to wait and will instead hit the power button, causing
us to lose the panic info.

This change configures the NMI period to watchdog_thresh and
sets the softlockup_thresh to watchdog_thresh * 2. In addition,
watchdog_thresh was reduced to 10 seconds as suggested by Ingo
Molnar.
Signed-off-by: NMandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-4-git-send-email-msb@chromium.orgSigned-off-by: NIngo Molnar <mingo@elte.hu>
LKML-Reference: <20110517071642.GF22305@elte.hu>

Stop including <linux/delay.h> in x86 header files which don't
need it. This will let the compiler complain when this header is
not included by source files when it should, so that
contributors can fix the problem before building on other
architectures starts to fail.

Credits go to Geert for the idea.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: James E.J. Bottomley <James.Bottomley@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
LKML-Reference: <20110325152014.297890ec@endymion.delvare>
[ this also fixes an upstream build bug in drivers/media/rc/ite-cir.c ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

show_regs() already prints two(!) stack traces, no need for a third one.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
LKML-Reference: <4D5D512902000078000326EE@vpn.id2.novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

With priorities in place and no one really understanding the difference between
DIE_NMI and DIE_NMI_IPI, just remove DIE_NMI_IPI and convert everyone to DIE_NMI.

This also simplifies default_do_nmi() a little bit.  Instead of calling the
die_notifier in both the if and else part, just pull it out and call it before
the if-statement.  This has the side benefit of avoiding a call to the ioport
to see if there is an external NMI sitting around until after the (more frequent)
internal NMIs are dealt with.
Patch-Inspired-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1294348732-15030-5-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In order to consolidate the NMI die_chain events, we need to setup the priorities
for the die notifiers.

I started by defining a bunch of common priorities that can be used by the
notifier blocks.  Then I modified the notifier blocks to use the newly created
priorities.

Now that the priorities are straightened out, it should be easier to remove the
event DIE_NMI_IPI.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1294348732-15030-4-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The spin_lock_debug/rcu_cpu_stall detector uses
trigger_all_cpu_backtrace() to dump cpu backtrace.
Therefore it is possible that trigger_all_cpu_backtrace()
could be called at the same time on different CPUs, which
triggers and 'unknown reason NMI' warning. The following case
illustrates the problem:

      CPU1                    CPU2                     ...   CPU N
                       trigger_all_cpu_backtrace()
                       set "backtrace_mask" to cpu mask
                               |
generate NMI interrupts  generate NMI interrupts       ...
    \                          |                               /
     \                         |                              /

The "backtrace_mask" will be cleaned by the first NMI interrupt
at nmi_watchdog_tick(), then the following NMI interrupts
generated by other cpus's arch_trigger_all_cpu_backtrace() will
be taken as unknown reason NMI interrupts.

This patch uses a test_and_set to avoid the problem, and stop
the arch_trigger_all_cpu_backtrace() from calling to avoid
dumping a double cpu backtrace info when there is already a
trigger_all_cpu_backtrace() in progress.
Signed-off-by: NDongdong Deng <dongdong.deng@windriver.com>
Reviewed-by: NBruce Ashfield <bruce.ashfield@windriver.com>
Cc: fweisbec@gmail.com
LKML-Reference: <1294198689-15447-2-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDon Zickus <dzickus@redhat.com>

There are some paths that walk the die_chain with preemption on.
Make sure we are in an NMI call before we start doing anything.

This was triggered by do_general_protection calling notify_die
with DIE_GPF.
Reported-by: NJan Kiszka <jan.kiszka@web.de>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
LKML-Reference: <1294198689-15447-1-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The x86 arch has shifted its use of the nmi_watchdog from a
local implementation to the global one provide by
kernel/watchdog.c.  This shift has caused a whole bunch of
compile problems under different config options.  I attempt to
simplify things with the patch below.

In order to simplify things, I had to come to terms with the
meaning of two terms ARCH_HAS_NMI_WATCHDOG and
CONFIG_HARDLOCKUP_DETECTOR.  Basically they mean the same thing,
the former on a local level and the latter on a global level.

With the old x86 nmi watchdog gone, there is no need to rely on
defining the ARCH_HAS_NMI_WATCHDOG variable because it doesn't
make sense any more.  x86 will now use the global
implementation.

The changes below do a few things.  First it changes the few
places that relied on ARCH_HAS_NMI_WATCHDOG to use
CONFIG_X86_LOCAL_APIC (the former was an alias for the latter
anyway, so nothing unusual here).  Those pieces of code were
relying more on local apic functionality the nmi watchdog
functionality, so the change should make sense.

Second, I removed the x86 implementation of
touch_nmi_watchdog().  It isn't need now, instead x86 will rely
on kernel/watchdog.c's implementation.

Third, I removed the #define ARCH_HAS_NMI_WATCHDOG itself from
x86.  And tweaked the include/linux/nmi.h file to tell users to
look for an externally defined touch_nmi_watchdog in the case of
ARCH_HAS_NMI_WATCHDOG _or_ CONFIG_HARDLOCKUP_DETECTOR. This
changes removes some of the ugliness in that file.

Finally, I added a Kconfig dependency for
CONFIG_HARDLOCKUP_DETECTOR that said you can't have
ARCH_HAS_NMI_WATCHDOG _and_ CONFIG_HARDLOCKUP_DETECTOR.  You can
only have one nmi_watchdog.

Tested with
ARCH=i386: allnoconfig, defconfig, allyesconfig, (various broken
configs) ARCH=x86_64: allnoconfig, defconfig, allyesconfig,
(various broken configs)

Hopefully, after this patch I won't get any more compile broken
emails. :-)

v3:
  changed a couple of 'linux/nmi.h' -> 'asm/nmi.h' to pick-up correct function
  prototypes when CONFIG_HARDLOCKUP_DETECTOR is not set.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1293044403-14117-1-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When adjusting the code to handle removing the old nmi watchdog,
I forgot to consider the compile case when the local apic is not
enabled.

This change fixes the following build error:

  arch/x86/kernel/apic/hw_nmi.c:28:6: error: redefinition of ‘touch_nmi_watchdog’
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Rakib Mullick <rakib.mullick@gmail.com>
LKML-Reference: <20101213153719.GD18577@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Originally adapted from Huang Ying's patch which moved the
unknown_nmi_panic to the traps.c file.  Because the old nmi
watchdog was deleted before this change happened, the
unknown_nmi_panic sysctl was lost.  This re-adds it.

Also, the nmi_watchdog sysctl was re-implemented and its
documentation updated accordingly.
Patch-inspired-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Reviewed-by: NCyrill Gorcunov <gorcunov@gmail.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

My patch that removed the old x86 nmi watchdog broke other
arches.  This change reverts a piece of that patch and puts the
change in the correct spot.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Reviewed-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: fweisbec@gmail.com
Cc: yinghai@kernel.org
LKML-Reference: <1291068437-5331-2-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/apic/hw_nmi.c:29: warning: backtrace_mask defined but not used

commit 0e2af2a9(x86, hw_nmi: Move backtrace_mask declaration under
ARCH_HAS_NMI_WATCHDOG) addressed this warning, but it was reintroduced
by commit 5f2b0ba4(x86, nmi_watchdog: Remove the old nmi_watchdog).

Move backtrace_mask into the #ifdef arch_trigger_all_cpu_backtrace
section again.
Signed-off-by: NRakib Mullick <rakib.mullick@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <AANLkTi=rcc38QzoKa6LFy4m++-p_9=Zt4_kDQE=GeKxf@mail.gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

backtrace_mask has been used under the code context of
ARCH_HAS_NMI_WATCHDOG. So put it into that context.
We were warned by the following warning:

  arch/x86/kernel/apic/hw_nmi.c:21: warning: ‘backtrace_mask’ defined but not used
Signed-off-by: NRakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
LKML-Reference: <1289573455-3410-2-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Now that the bulk of the old nmi_watchdog is gone, remove all
the stub variables and hooks associated with it.

This touches lots of files mainly because of how the io_apic
nmi_watchdog was implemented.  Now that the io_apic nmi_watchdog
is forever gone, remove all its fingers.

Most of this code was not being exercised by virtue of
nmi_watchdog != NMI_IO_APIC, so there shouldn't be anything to
risky here.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: fweisbec@gmail.com
Cc: gorcunov@openvz.org
LKML-Reference: <1289578944-28564-3-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Now that we have a new nmi_watchdog that is more generic and
sits on top of the perf subsystem, we really do not need the old
nmi_watchdog any more.

In addition, the old nmi_watchdog doesn't really work if you are
using the default clocksource, hpet.  The old nmi_watchdog code
relied on local apic interrupts to determine if the cpu is still
alive.  With hpet as the clocksource, these interrupts don't
increment any more and the old nmi_watchdog triggers false
postives.

This piece removes the old nmi_watchdog code and stubs out any
variables and functions calls.  The stubs are the same ones used
by the new nmi_watchdog code, so it should be well tested.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: fweisbec@gmail.com
Cc: gorcunov@openvz.org
LKML-Reference: <1289578944-28564-2-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

On some configs the following build error triggers:

 arch/x86/kernel/apic/hw_nmi.c:35: error: 'apic' undeclared (first use in this function)
 arch/x86/kernel/apic/hw_nmi.c:35: error: (Each undeclared identifier is reported only once
 arch/x86/kernel/apic/hw_nmi.c:35: error: for each function it appears in.)

Because asm/apic.h was only included implicitly. Include it explicitly.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <1273713674-8434-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The design of the hardlockup watchdog has changed and cruft was left
behind in the hw_nmi.c file.  Just remove the code that isn't used
anymore.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-7-git-send-email-dzickus@redhat.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

As part of the transition of the nmi watchdog to something more
generic, the trigger_all_cpu_backtrace code is getting left behind.
Put it in its own die_notifier so it can still be used.

V2:
- use arch_spin_locks
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

The new nmi_watchdog (which uses the perf event subsystem) is very
similar in structure to the softlockup detector.  Using Ingo's
suggestion, I combined the two functionalities into one file:
kernel/watchdog.c.

Now both the nmi_watchdog (or hardlockup detector) and softlockup
detector sit on top of the perf event subsystem, which is run every
60 seconds or so to see if there are any lockups.

To detect hardlockups, cpus not responding to interrupts, I
implemented an hrtimer that runs 5 times for every perf event
overflow event.  If that stops counting on a cpu, then the cpu is
most likely in trouble.

To detect softlockups, tasks not yielding to the scheduler, I used the
previous kthread idea that now gets kicked every time the hrtimer fires.
If the kthread isn't being scheduled neither is anyone else and the
warning is printed to the console.

I tested this on x86_64 and both the softlockup and hardlockup paths
work.

V2:
- cleaned up the Kconfig and softlockup combination
- surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI
- seperated out the softlockup case from perf event subsystem
- re-arranged the enabling/disabling nmi watchdog from proc space
- added cpumasks for hardlockup failure cases
- removed fallback to soft events if no PMU exists for hard events

V3:
- comment cleanups
- drop support for older softlockup code
- per_cpu cleanups
- completely remove software clock base hardlockup detector
- use per_cpu masking on hard/soft lockup detection
- #ifdef cleanups
- rename config option NMI_WATCHDOG to LOCKUP_DETECTOR
- documentation additions

V4:
- documentation fixes
- convert per_cpu to __get_cpu_var
- powerpc compile fixes

V5:
- split apart warn flags for hard and soft lockups

TODO:
- figure out how to make an arch-agnostic clock2cycles call
  (if possible) to feed into perf events as a sample period

[fweisbec: merged conflict patch]
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Mostly copy/paste whitespace damage with a couple of nitpicks by
the checkpatch script. Fix the struct definition as requested by Ingo too.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: peterz@infradead.org
Cc: gorcunov@gmail.com
Cc: aris@redhat.com
LKML-Reference: <1266880143-24943-1-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
--
 arch/x86/kernel/apic/hw_nmi.c |   14 +++++------
 arch/x86/kernel/traps.c       |    6 ++--
 include/linux/nmi.h           |    2 -
 kernel/nmi_watchdog.c         |   51 ++++++++++++++++++++----------------------
 4 files changed, 36 insertions(+), 37 deletions(-)

Ingo provided me a config that fails to compile with:

  arch/x86/built-in.o: In function
  `arch_trigger_all_cpu_backtrace': (.text+0x17e78): undefined
  reference to `apic' make: *** [.tmp_vmlinux1] Error 1

I realized I changed the compile behaviour of the nmi code by
not wrapping it with CONFIG_LOCAL_APIC.  To fix this I add a
compile check for ARCH_HAS_NMI_WATCHDOG around
arch_trigger_all_cpu_backtrace.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: a.p.zijlstra@chello.nl
Cc: gorcunov@gmail.com
Cc: aris@redhat.com
LKML-Reference: <1266548212-24243-1-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The original patch was x86_64 centric.  Changed the code to make
it less so.

ested by building and running on a powerpc.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: peterz@infradead.org
Cc: gorcunov@gmail.com
Cc: aris@redhat.com
LKML-Reference: <1266013161-31197-2-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This is a new generic nmi_watchdog implementation using the perf
events infrastructure as suggested by Ingo.

The implementation is simple, just create an in-kernel perf
event and register an overflow handler to check for cpu lockups.

I created a generic implementation that lives in kernel/ and
the hardware specific part that for now lives in arch/x86.

This approach has a number of advantages:

 - It simplifies the x86 PMU implementation in the long run,
   in that it removes the hardcoded low-level PMU implementation
   that was the NMI watchdog before.

 - It allows new NMI watchdog features to be added in a central
   place.

 - It allows other architectures to enable the NMI watchdog,
   as long as they have perf events (that provide NMIs)
   implemented.

 - It also allows for more graceful co-existence of existing
   perf events apps and the NMI watchdog - before these changes
   the relationship was exclusive. (The NMI watchdog will 'spend'
   a perf event when enabled. In later iterations we might be
   able to piggyback from an existing NMI event without having
   to allocate a hardware event for the NMI watchdog - turning
   this into a no-hardware-cost feature.)

As for compatibility, we'll keep the old NMI watchdog code as
well until the new one can 100% replace it on all CPUs, old and
new alike.  That might take some time as the NMI watchdog has
been ported to many CPU models.

I have done light testing to make sure the framework works
correctly and it does.

 v2: Set the correct timeout values based on the old nmi
     watchdog
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: gorcunov@gmail.com
Cc: aris@redhat.com
Cc: peterz@infradead.org
LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>