pc_clock_settime() and pc_clock_adjtime() do not check whether the fd
was opened in write mode, so a clock can be set with a read only fd.

[ tglx: We deliberately do not return -EPERM as we want this to be
  	distingushable from the capability based permission check ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
LKML-Reference: <1299173174-348-4-git-send-email-torbenh@gmx.de>
Cc: Richard Cochran <richard.cochran@omicron.at>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>

When the per cpu timer is marked CLOCK_EVT_FEAT_C3STOP, then we only
can switch into oneshot mode, when the backup broadcast device
supports oneshot mode as well. Otherwise we would try to switch the
broadcast device into an unsupported mode unconditionally. This went
unnoticed so far as the current available broadcast devices support
oneshot mode. Seth unearthed this problem while debugging and working
around an hpet related BIOS wreckage.

Add the necessary check to tick_is_oneshot_available().
Reported-and-tested-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <alpine.LFD.2.00.1102252231200.2701@localhost6.localdomain6>
Cc: stable@kernel.org # .21 ->

Extend get_xtime_and_monotonic_offset to
get_xtime_and_monotonic_and_sleep_offset().

CC: Jamie Lokier <jamie@shareable.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alexander Shishkin <virtuoso@slind.org>
CC: Arve Hjønnevåg <arve@android.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

This adds new functions that return the monotonic time since boot
(in other words, CLOCK_MONOTONIC + suspend time).

CC: Jamie Lokier <jamie@shareable.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alexander Shishkin <virtuoso@slind.org>
CC: Arve Hjønnevåg <arve@android.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

The ADJ_SETOFFSET code redundantly checks the range of the nanoseconds
field of the time value. This field is checked again in the subsequent
call to timekeeping_inject_offset(). Also, as is, the check will not
detect whether the number of microseconds is out of range.

Let timekeeping_inject_offset() do the error checking.
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
Cc: johnstul@us.ibm.com
LKML-Reference: <20110218090724.GA2924@riccoc20.at.omicron.at>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

In the continuing effort to avoid kernel addresses leaking to
unprivileged users, this patch switches to %pK for
/proc/timer_list reporting.
Signed-off-by: NKees Cook <kees.cook@canonical.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: Eugene Teo <eugeneteo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110212032125.GA23571@outflux.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch adds support for adding and removing posix clocks. The
clock lifetime cycle is patterned after usb devices. Each clock is
represented by a standard character device. In addition, the driver
may optionally implement custom character device operations.

The posix clock and timer system calls listed below now work with
dynamic posix clocks, as well as the traditional static clocks.
The following system calls are affected:

   - clock_adjtime (brand new syscall)
   - clock_gettime
   - clock_getres
   - clock_settime
   - timer_create
   - timer_delete
   - timer_gettime
   - timer_settime

[ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
  	to posix-clock.c and made all referenced functions static ]
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <20110201134420.164172635@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch adds a new mode bit into the timex structure. When set, the bit
instructs the kernel to add the given time value to the current time.
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <20110201134320.688829863@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This adds a kernel-internal timekeeping interface to add or subtract
a fixed amount from CLOCK_REALTIME. This makes it so kernel users or
interfaces trying to do so do not have to read the time, then add an
offset and then call settimeofday(), which adds some extra error in
comparision to just simply adding the offset in the kernel timekeeping
core.
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
LKML-Reference: <20110201134419.584311693@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Both settimeofday() and clock_settime() promise with a 'const'
attribute not to alter the arguments passed in. This patch adds the
missing 'const' attribute into the various kernel functions
implementing these calls.
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <20110201134417.545698637@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The xtime/dotimer cleanup broke architectures which do not implement
clockevents. Time to send out another __do_IRQ threat.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reported-by: NIngo Molnar <mingo@elte.hu>
Cc: Torben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145905.23248.30458.stgit@localhost>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

All callers of do_timer() are converted to xtime_update(). The only
users of xtime_lock are in kernel/time/. Make both local to
kernel/time/ and remove them from the global header files.

[ tglx: Reuse tick-internal.h instead of creating another local header
  	file. Massaged changelog ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

xtime_update() takes xtime_lock write locked and calls
do_timer(). Provided to replace the do_timer() calls in the
architecture code.
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145910.23248.21379.stgit@localhost>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

No users left. Remove it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The hrtimer code accesses timekeeping variables under
xtime_lock. Provide a sensible accessor function and use it.

[ tglx: Removed the conditionals, unused variable, fixed codingstyle
  	and massaged changelog ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145905.23248.30458.stgit@localhost>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Move the jiffies access functions to the jiffies clocksource code.

[ tglx: Add missing include ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145900.23248.73352.stgit@localhost>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

do_timer() is primary timekeeping related. calc_global_load() is
called from do_timer() as well, but that's more for historical
reasons.

[ tglx: Fixed up the calc_global_load() reject andmassaged changelog ]
Signed-off-by: NTorben Hohn <torbenh@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: yong.zhang0@gmail.com
Cc: hch@infradead.org
LKML-Reference: <20110127145855.23248.56933.stgit@localhost>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

When NOHZ=y and high res timers are disabled (via cmdline or
Kconfig) tick_nohz_switch_to_nohz() will notify the user about
switching into NOHZ mode. Nothing is printed for the case where
HIGH_RES_TIMERS=y. Fix this for the HIGH_RES_TIMERS=y case by
duplicating the printk from the low res NOHZ path in the high
res NOHZ path.

This confused me since I was thinking 'dmesg | grep -i NOHZ' would
tell me if NOHZ was enabled, but if I have hrtimers there is
nothing.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1295419594-13085-1-git-send-email-sboyd@codeaurora.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

MONOTONIC_RAW clock timestamps are ideally suited for frequency
calculation and also fit well into the original NTP hardpps design.  Now
phase and frequency can be adjusted separately: the former based on
REALTIME clock and the latter based on MONOTONIC_RAW clock.

A new function getnstime_raw_and_real is added to timekeeping subsystem to
capture both timestamps at the same time and atomically.
Signed-off-by: NAlexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This commit adds hardpps() implementation based upon the original one from
the NTPv4 reference kernel code from David Mills.  However, it is highly
optimized towards very fast syncronization and maximum stickness to PPS
signal.  The typical error is less then a microsecond.

To make it sync faster I had to throw away exponential phase filter so
that the full phase offset is corrected immediately.  Then I also had to
throw away median phase filter because it gives a bigger error itself if
used without exponential filter.

Maybe we will find an appropriate filtering scheme in the future but it's
not necessary if the signal quality is ok.
Signed-off-by: NAlexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <0D753D10438DA54287A00B027084269764CE0E54B7@AUSP01VMBX24.collaborationhost.net>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The minsec argument to clocks_calc_mult_shift() is misnamed. It is used 
to clamp the magnitude of the mult factor so that a multiplication with 
any value in the given range won't overflow a 64 bit result.  Let's 
rename it to match the actual usage.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <alpine.LFD.2.00.1101111207140.17086@xanadu.home>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Russell King reports:
| On the ARM dev boards, we have a 32-bit counter running at 24MHz.  Calling
| clocks_calc_mult_shift(&mult, &shift, 24MHz, NSEC_PER_SEC, 60) gives
| us a multiplier of 2796202666 and a shift of 26.
|
| Over a large counter delta, this produces an error - lets take a count
| from 362976315 to 4280663372:
|
| (4280663372-362976315) * 2796202666 / 2^26 - (4280663372-362976315) * (1000/24)
|  => -38.91872422891230269990
|
| Can we do better?
|
| (4280663372-362976315) * 2796202667 / 2^26 - (4280663372-362976315) * (1000/24)
| 19.45936211449532822051
|
| which is about twice as good as the 2796202666 multiplier.
|
| Looking at the equivalent divisions obtained, 2796202666 / 2^26 gives
| 41.66666665673255920410ns per tick, whereas 2796202667 / 2^26 gives
| 41.66666667163372039794ns.  The actual value wanted is 1000/24 =
| 41.66666666666666666666ns.

Fix this by ensuring we round to nearest when calculating the
multiplier.
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NMikael Pettersson <mikpe@it.uu.se>
Tested-by: NEric Miao <eric.y.miao@gmail.com>
Tested-by: NOlof Johansson <olof@lixom.net>
Tested-by: NJamie Iles <jamie@jamieiles.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

__get_cpu_var() can be replaced with this_cpu_read and will then use a
single read instruction with implied address calculation to access the
correct per cpu instance.

However, the address of a per cpu variable passed to __this_cpu_read()
cannot be determined (since it's an implied address conversion through
segment prefixes).  Therefore apply this only to uses of __get_cpu_var
where the address of the variable is not used.

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hughd@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Converts the hrtimer code to use the new timerlist infrastructure
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
LKML Reference: <1290136329-18291-3-git-send-email-john.stultz@linaro.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Richard Cochran <richardcochran@gmail.com>

"gadget", "through", "command", "maintain", "maintain", "controller", "address",
"between", "initiali[zs]e", "instead", "function", "select", "already",
"equal", "access", "management", "hierarchy", "registration", "interest",
"relative", "memory", "offset", "already",
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Replace sizeof(buffer)/sizeof(buffer[0]) with ARRAY_SIZE(buffer) in
kernel/time/timecompare.c
Signed-off-by: NNikitas Angelinas <nikitasangelinas@googlemail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

When the clocksource is not a multiple of HZ, the clock will be off.  For
acpi_pm, HZ=1000 the error is 127.111 ppm:

The rounding of cycle_interval ends up generating a false error term in
ntp_error accumulation since xtime_interval is not exactly 1/HZ.  So, we
subtract out the error caused by the rounding.

This has been visible since 2.6.32-rc2
	commit a092ff0f
	time: Implement logarithmic time accumulation
That commit raised NTP_INTERVAL_FREQ and exposed the rounding error.

testing tool: http://n1.taur.dk/permanent/testpmt.c
Also tested with ntpd and a frequency counter.
Signed-off-by: NKasper Pedersen <kkp2010@kasperkp.dk>
Acked-by: Njohn stultz <johnstul@us.ibm.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Clamp update interval to reduce PLL gain with low sampling rate (e.g.
intermittent network connection) to avoid instability.

The clamp roughly corresponds to the loop time constant, it's 8 * poll
interval for SHIFT_PLL 2 and 32 * poll interval for SHIFT_PLL 4. This
gives good results without affecting the gain in normal conditions where
ntpd skips only up to seven consecutive samples.
Signed-off-by: NMiroslav Lichvar <mlichvar@redhat.com>
Acked-by: Njohn stultz <johnstul@us.ibm.com>
LKML-Reference: <1283870626-9472-1-git-send-email-mlichvar@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Early 4.3 versions of gcc apparently aggressively optimize the raw
time accumulation loop, replacing it with a divide.

On 32bit systems, this causes the following link errors:
	undefined reference to `__umoddi3'
	undefined reference to `__udivdi3'

The gcc issue has been fixed in 4.4 and greater.

This patch replaces the accumulation loop with a do_div, as suggested
by Linus.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
CC: Jason Wessel <jason.wessel@windriver.com>
CC: Larry Finger <Larry.Finger@lwfinger.net>
CC: Ingo Molnar <mingo@elte.hu>
CC: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The tv_nsec is a long and when added to the shifted interval it can wrap
and become negative which later causes looping problems in the
getrawmonotonic().  The edge case occurs when the system has slept for
a short period of time of ~2 seconds.

A trace printk of the values in this patch illustrate the problem:

ftrace time stamp: log
43.716079: logarithmic_accumulation: raw: 3d0913 tv_nsec d687faa
43.718513: logarithmic_accumulation: raw: 3d0913 tv_nsec da588bd
43.722161: logarithmic_accumulation: raw: 3d0913 tv_nsec de291d0
46.349925: logarithmic_accumulation: raw: 7a122600 tv_nsec e1f9ae3b
46.349930: logarithmic_accumulation: raw: 1e848980 tv_nsec 8831c0e3

The kernel starts looping at 46.349925 in the getrawmonotonic() due to
the negative value from adding the raw value to tv_nsec.

A simple solution is to accumulate into a u64, and then normalize it
to a timespec_t.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
 [ Reworked variable names and simplified some of the code. - John ]
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Historically, Linux has tried to make the regular timer tick on the
various CPUs not happen at the same time, to avoid contention on
xtime_lock.

Nowadays, with the tickless kernel, this contention no longer happens
since time keeping and updating are done differently. In addition,
this skew is actually hurting power consumption in a measurable way on
many-core systems.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20100727210210.58d3118c@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

To properly handle clocksources that change frequencies
at the clocksource->enable() point, this patch adds
a method that will update the clocksource's mult/shift and
max_idle_ns values.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-12-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch makes xtime and wall_to_monotonic static, as planned in
Documentation/feature-removal-schedule.txt. This will allow for
further cleanups to the timekeeping core.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-10-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Provides an accessor function to replace hrtimer.c's
direct access of wall_to_monotonic.

This will allow wall_to_monotonic to be made static as
planned in Documentation/feature-removal-schedule.txt
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-9-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

update_vsyscall() did not provide the wall_to_monotoinc offset,
so arch specific implementations tend to reference wall_to_monotonic
directly. This limits future cleanups in the timekeeping core, so
this patch fixes the update_vsyscall interface to provide
wall_to_monotonic, allowing wall_to_monotonic to be made static
as planned in Documentation/feature-removal-schedule.txt
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tony Luck <tony.luck@intel.com>
LKML-Reference: <1279068988-21864-7-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Now that all arches have been converted over to use generic time via
clocksources or arch_gettimeoffset(), we can remove the GENERIC_TIME
config option and simplify the generic code.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-4-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

After accidentally misusing timespec_add_safe, I wanted to make sure
we don't accidently trip over that issue again, so I created a simple
timespec_add() function which we can use to replace the instances
of timespec_add_safe() that don't want the overflow detection.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-3-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Norbert reported that nohz_ratelimit() causes his laptop to burn about
4W (40%) extra. For now back out the change and see if we can adjust
the power management code to make better decisions.
Reported-by: NNorbert Preining <preining@logic.at>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NMike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>