UserTimer: Zero-initialize sigevents.

CID 1234670 and friends. Probably harmless, though.

kernel: Fix NULL dereference in ThreadTimeUserTimer::Schedule().

The SpinLocker was always initialized to fThread->time_lock even though
fThread may be NULL. This looks like a simple oversight as the rest of
the method handles fThread being NULL and the team variants of these
timers have very similar logic and do the NULL check as well.

This fixes the last remaining KDL in the posixtestsuite.

kernel: Workaround for double lock of spinlock in user timers.

The thread that is being [un]scheduled already has its time_lock locked
in {stop|continue}_cpu_timers(). When updating the TeamTimeUserTimer,
the team is asked for its cpu time. Team::CPUTime() then iterates the
threads of the team and locks the time_lock of the thread again.

This workaround passes a possibly locked thread through the relevant
functions so Team::CPUTime() can decide whether or not a thread it
iterates needs to be locked or not.

This works around #11032 and its duplicates #11314 and #11344.

kernel/UserEvent: Make sure UserEvent object is valid during DPC

Most of the actual UserEvent work is done in DPC so that we don't have
to care about the limitations of the context in which UserEvent::Fire()
is invoked. This requires appropriate management of lifetime of UserEvent
instances to make sure that DoDPC() method is always called on a valid
object.

kernel: Rework cpuidle module

* Create new interface for cpuidle modules (similar to the cpufreq
interface)
* Generic cpuidle module is no longer needed
* Fix and update Intel C-State module

kernel: Introduce Thread::time_lock and Team::time_lock

kernel: User{Event, Timer}: Use atomic access where necessary

kernel: Protect UserTimers with sUserTimerLock

kernel: Remove B_TIMER_ACQUIRE_SCHEDULER_LOCK flag

The flag main purpose is to avoid race conditions between event handler
and cancel_timer(). However, cancel_timer() is safe even without
using gSchedulerLock.

If the event is scheduled to happen on other CPU than the CPU that
invokes cancel_timer() then cancel_timer() either disables the event
before its handler starts executing or waits until the event handler
is done.

If the event is scheduled on the same CPU that calls cancel_timer()
then, since cancel_timer() disables interrupts, the event is either
executed before cancel_timer() or when the timer interrupt handler
starts running the event is already disabled.

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96

kernel: Workaround for double lock of spinlock in user timers.

The thread that is being [un]scheduled already has its time_lock locked
in {stop|continue}_cpu_timers(). When updating the TeamTimeUserTimer,
the team is asked for its cpu time. Team::CPUTime() then iterates the
threads of the team and locks the time_lock of the thread again.

This workaround passes a possibly locked thread through the relevant
functions so Team::CPUTime() can decide whether or not a thread it
iterates needs to be locked or not.

This works around #11032 and its duplicates #11314 and #11344.

kernel/UserEvent: Make sure UserEvent object is valid during DPC

Most of the actual UserEvent work is done in DPC so that we don't have
to care about the limitations of the context in which UserEvent::Fire()
is invoked. This requires appropriate management of lifetime of UserEvent
instances to make sure that DoDPC() method is always called on a valid
object.

kernel: Rework cpuidle module

* Create new interface for cpuidle modules (similar to the cpufreq
interface)
* Generic cpuidle module is no longer needed
* Fix and update Intel C-State module

kernel: Introduce Thread::time_lock and Team::time_lock

kernel: User{Event, Timer}: Use atomic access where necessary

kernel: Protect UserTimers with sUserTimerLock

kernel: Remove B_TIMER_ACQUIRE_SCHEDULER_LOCK flag

The flag main purpose is to avoid race conditions between event handler
and cancel_timer(). However, cancel_timer() is safe even without
using gSchedulerLock.

If the event is scheduled to happen on other CPU than the CPU that
invokes cancel_timer() then cancel_timer() either disables the event
before its handler starts executing or waits until the event handler
is done.

If the event is scheduled on the same CPU that calls cancel_timer()
then, since cancel_timer() disables interrupts, the event is either
executed before cancel_timer() or when the timer interrupt handler
starts running the event is already disabled.

Merged signals-merge branch into trunk with the following changes:
* Reorganized the kernel locking related to threads and teams.
* We now discriminate correctly between process and thread signals. Signal
handlers have been moved to teams. Fixes #5679.
* Implemented real-time signal support, including signal queuing, SA_SIGINFO
support, sigqueue(), sigwaitinfo(), sigtimedwait(), waitid(), and the addition
of the real-time signal range. Closes #1935 and #2695.
* Gave SIGBUS a separate signal number. Fixes #6704.
* Implemented <time.h> clock and timer support, and fixed/completed alarm() and
[set]itimer(). Closes #5682.
* Implemented support for thread cancellation. Closes #5686.
* Moved send_signal() from <signal.h> to <OS.h>. Fixes #7554.
* Lots over smaller more or less related changes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42116 a95241bf-73f2-0310-859d-f6bbb57e9c96