Combining the softlockup and hardlockup code causes watchdog.c
to build even without the hardlockup detection support.

So if an arch, that has the previous and the new nmi watchdog
implementations cohabiting, wants to know if the generic one
is in use, CONFIG_LOCKUP_DETECTOR is not a reliable check.
We need to use CONFIG_HARDLOCKUP_DETECTOR instead.

Fixes:
	kernel/built-in.o: In function `touch_nmi_watchdog':
	(.text+0x449bc): multiple definition of `touch_nmi_watchdog'
	arch/sparc/kernel/built-in.o:(.text+0x11b28): first defined here
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <20100514151121.GR15159@redhat.com>
[ use CONFIG_HARDLOCKUP_DETECTOR instead of CONFIG_PERF_EVENTS_NMI]
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>

These are the bits that enable the new nmi_watchdog and safely
isolate the old nmi_watchdog.  Only one or the other can run,
not both at the same time.
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: <1265424425-31562-4-git-send-email-dzickus@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Introduce NOOP APIC driver. We should use it in case if apic was
disabled due to hardware of software/firmware problems (including
user requested to disable it case).

The driver is attempting to catch any inappropriate apic operation
call with warning issue.

Also it is possible to use some apic operation like IPI calls,
read/write without checking for apic presence which should make
callers code easier.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: yinghai@kernel.org
Cc: macro@linux-mips.org
LKML-Reference: <20091013201022.534682104@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: build fix, cleanup

A couple of arch setup callbacks were mistakenly in apic_32.c, breaking
the build.

Also simplify the code a bit.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move the 32-bit extended-arch APIC drivers to arch/x86/kernel/apic/
too, and rename apic_64.c to probe_64.c.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/ is getting a bit crowded, and the APIC
drivers are scattered into various different files.

Move them to arch/x86/kernel/apic/*, and also remove
the 'gen' prefix from those which had it.

Also move APIC related functionality: the IO-APIC driver,
the NMI and the IPI code.
Signed-off-by: NIngo Molnar <mingo@elte.hu>