Commit Graph

6 Commits

Author SHA1 Message Date
Yang Yingliang 1f45f1f33c clocksource: Make clocksource validation work for all clocksources
The clocksource validation which makes sure that the newly read value
is not smaller than the last value only works if the clocksource mask
is 64bit, i.e. the counter is 64bit wide. But we want to use that
mechanism also for clocksources which are less than 64bit wide.

So instead of checking whether bit 63 is set, we check whether the
most significant bit of the clocksource mask is set in the delta
result. If it is set, we return 0.

[ tglx: Simplified the implementation, added a comment and massaged
  	the commit message ]

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Link: http://lkml.kernel.org/r/56349607.6070708@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-12-19 15:59:57 +01:00
DengChao dee3665416 timekeeping: Provide internal function __ktime_get_real_seconds
In order to fix Y2038 issues in the ntp code we will need replace
get_seconds() with ktime_get_real_seconds() but as the ntp code uses
the timekeeping lock which is also used by ktime_get_real_seconds(),
we need a version without locking.
Add a new function __ktime_get_real_seconds() in timekeeping to
do this.

Reviewed-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: DengChao <chao.deng@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-16 16:50:55 -08:00
Thomas Gleixner 09ec54429c clocksource: Move cycle_last validation to core code
The only user of the cycle_last validation is the x86 TSC. In order to
provide NMI safe accessor functions for clock monotonic and
monotonic_raw we need to do that in the core.

We can't do the TSC specific

    if (now < cycle_last)
       	    now = cycle_last;

for the other wrapping around clocksources, but TSC has
CLOCKSOURCE_MASK(64) which actually does not mask out anything so if
now is less than cycle_last the subtraction will give a negative
result. So we can check for that in clocksource_delta() and return 0
for that case.

Implement and enable it for x86

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23 15:01:51 -07:00
Thomas Gleixner 3a97837784 clocksource: Make delta calculation a function
We want to move the TSC sanity check into core code to make NMI safe
accessors to clock monotonic[_raw] possible. For this we need to
sanity check the delta calculation. Create a helper function and
convert all sites to use it.

[ Build fix from jstultz ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23 15:01:51 -07:00
John Stultz 7d489d15ce timekeeping: Convert timekeeping core to use timespec64s
Convert the core timekeeping logic to use timespec64s. This moves the
2038 issues out of the core logic and into all of the accessor
functions.

Future changes will need to push the timespec64s out to all
timekeeping users, but that can be done interface by interface.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23 10:17:54 -07:00
Colin Cross 5c83545f24 power: Add option to log time spent in suspend
Below is a patch from android kernel that maintains a histogram of
suspend times. Please review and provide feedback.

Statistices on the time spent in suspend are kept in
/sys/kernel/debug/sleep_time.

Cc: Android Kernel Team <kernel-team@android.com>
Cc: Colin Cross <ccross@android.com>
Cc: Todd Poynor <toddpoynor@google.com>
Cc: San Mehat <san@google.com>
Cc: Benoit Goby <benoit@android.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
[zoran.markovic@linaro.org: Re-formatted suspend time table to better
fit expected values. Moved accounting of suspend time into timekeeping
core. Removed CONFIG_SUSPEND_TIME flag and made the feature conditional
on CONFIG_DEBUG_FS. Changed the file name to sleep_time to better fit
terminology in timekeeping core. Changed seq_printf to seq_puts. Tweaked
commit message]
Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-05-29 12:57:34 -07:00