linux.git/arch/s390/kernel/time.c, branch v3.15

s390/irq: Use defines for external interruption codes

2014-04-03T12:30:52+00:00

Use the new defines for external interruption codes to get rid
of "magic" numbers in the s390 source code. And while we're at it,
also rename the (un-)register_external_interrupt function to
something shorter so that this patch does not exceed the 80
columns all over the place.

Signed-off-by: Thomas Huth 
Signed-off-by: Martin Schwidefsky

s390,time: revert direct ktime path for s390 clockevent device

2013-11-25T08:15:41+00:00

Git commit 4f37a68cdaf6dea833cfdded2a3e0c47c0f006da
"s390: Use direct ktime path for s390 clockevent device" makes use
of the CLOCK_EVT_FEAT_KTIME clockevent option to avoid the delta
calculation with ktime_get() in clockevents_program_event and the
get_tod_clock() in s390_next_event. This is based on the assumption
that the difference between the internal ktime and the hardware
clock is reflected in the wall_to_monotonic delta. But this is not
true, the ntp corrections are applied via changes to the tk->mult
multiplier and this is not reflected in wall_to_monotonic.

In theory this could be solved by using the raw monotonic clock
but it is simpler to switch back to the standard clock delta
calculation.

Signed-off-by: Martin Schwidefsky

s390/time,vdso: convert to the new update_vsyscall interface

2013-11-25T08:15:39+00:00

Switch to the improved update_vsyscall interface that provides
sub-nanosecond precision for gettimeofday and clock_gettime.

Signed-off-by: Martin Schwidefsky

s390/time: return with irqs disabled from psw_idle

2013-08-28T07:19:23+00:00

Modify the psw_idle waiting logic in entry[64].S to return with
interrupts disabled. This avoids potential issues with udelay
and interrupt loops as interrupts are not reenabled after
clock comparator interrupts.

Signed-off-by: Martin Schwidefsky

s390/time: rename tod clock access functions

2013-02-14T14:55:10+00:00

Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/timer: avoid overflow when programming clock comparator

2013-01-31T13:01:52+00:00

Since ed4f209 "s390/time: fix sched_clock() overflow" a new helper function
is used to avoid overflows when converting TOD format values to nanosecond
values.
The kvm interrupt code formerly however only worked by accident because of
an overflow. It tried to program a timer that would expire in more than ~29
years. Because of the old TOD-to-nanoseconds overflow bug the real expiry
value however was much smaller, but now it isn't anymore.
This however triggers yet another bug in the function that programs the clock
comparator s390_next_ktime(): if the absolute "expires" value is after 2042
this will result in an overflow and the programmed value is lower than the
current TOD value which immediatly triggers a clock comparator (= timer)
interrupt.
Since the timer isn't expired it will be programmed immediately again and so
on... the result is a dead system.
To fix this simply program the maximum possible value if an overflow is
detected.

Reported-by: Christian Borntraeger 
Tested-by: Christian Borntraeger 
Cc: stable@vger.kernel.org # v3.3+
Signed-off-by: Heiko Carstens

s390/time: fix sched_clock() overflow

2013-01-16T14:57:52+00:00

Converting a 64 Bit TOD format value to nanoseconds means that the value
must be divided by 4.096. In order to achieve that we multiply with 125
and divide by 512.
When used within sched_clock() this triggers an overflow after appr.
417 days. Resulting in a sched_clock() return value that is much smaller
than previously and therefore may cause all sort of weird things in
subsystems that rely on a monotonic sched_clock() behaviour.

To fix this implement a tod_to_ns() helper function which converts TOD
values without overflow and call this function from both places that
open coded the conversion: sched_clock() and kvm_s390_handle_wait().

Cc: stable@kernel.org
Reviewed-by: Martin Schwidefsky 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/irq: remove split irq fields from /proc/stat

2013-01-08T09:57:07+00:00

Now that irq sum accounting for /proc/stat's "intr" line works again we
have the oddity that the sum field (first field) contains only the sum
of the second (external irqs) and third field (I/O interrupts).
The reason for that is that these two fields are already sums of all other
fields. So if we would sum up everything we would count every interrupt
twice.
This is broken since the split interrupt accounting was merged two years
ago: 052ff461c8427629aee887ccc27478fc7373237c "[S390] irq: have detailed
statistics for interrupt types".
To fix this remove the split interrupt fields from /proc/stat's "intr"
line again and only have them in /proc/interrupts.

This restores the old behaviour, seems to be the only sane fix and mimics
a behaviour from other architectures where /proc/interrupts also contains
more than /proc/stat's "intr" line does.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-10-12T13:17:48+00:00

Pull timer core update from Thomas Gleixner:
 - Bug fixes (one for a longstanding dead loop issue)
 - Rework of time related vsyscalls
 - Alarm timer updates
 - Jiffies updates to remove compile time dependencies

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Cast raw_interval to u64 to avoid shift overflow
  timers: Fix endless looping between cascade() and internal_add_timer()
  time/jiffies: bring back unconditional LATCH definition
  time: Convert x86_64 to using new update_vsyscall
  time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems
  time: Introduce new GENERIC_TIME_VSYSCALL
  time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD
  time: Move update_vsyscall definitions to timekeeper_internal.h
  time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes
  jiffies: Remove compile time assumptions about CLOCK_TICK_RATE
  jiffies: Kill unused TICK_USEC_TO_NSEC
  alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue
  alarmtimer: Remove unused helpers & defines
  alarmtimer: Use hrtimer per-alarm instead of per-base
  alarmtimer: Implement minimum alarm interval for allowing suspend

s390/etr,stp: use -EOPNOTSUPP instead of -ENOSYS

2012-09-26T13:45:14+00:00

Change -ENOSYS to -EOPNOTSUPP. Return value is used only internally.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky