The cr16 clocks of the physical PARISC CPUs are usually nonsynchronous.
Nevertheless, it seems that each CPU socket (which holds two cores) of
PA8800 and PA8900 CPUs (e.g. in a C8000 workstation) is fed by the same
clock source, which makes the cr16 clocks of each CPU socket syncronous.
Let's try to detect such situations and mark the cr16 clocksource stable
on single-socket and single-core machines.
Signed-off-by: Helge Deller <deller@gmx.de>
We are going to split <linux/sched/clock.h> out of <linux/sched.h>, which
will have to be picked up from other headers and .c files.
Create a trivial placeholder <linux/sched/clock.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The cr16 interval timer of each CPU is not syncronized to other cr16
timers in other CPUs in a SMP system. So, delay the registration of the
cr16 clocksource until all CPUs have been detected and then - if we are
on a SMP machine - mark the cr16 clocksource as unstable and lower it's
rating before registering it at the clocksource framework.
This patch fixes the stalled CPU warnings which we have seen since
introduction of the cr16 clocksource.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.8+
There is no point in having an extra type for extra confusion. u64 is
unambiguous.
Conversion was done with the following coccinelle script:
@rem@
@@
-typedef u64 cycle_t;
@fix@
typedef cycle_t;
@@
-cycle_t
+u64
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Restructure the timer interrupt function to better cope with missed timer irqs.
Optimize the calculation when the next interrupt should happen and skip irqs if
they would happen too shortly after exit of the irq function.
The update_process_times() call is done anyway at every timer irq, so we can
safely drop the prof_counter and prof_multiplier variables from the per_cpu
structure.
Signed-off-by: Helge Deller <deller@gmx.de>
Drop the open-coded sched_clock() function and replace it by the provided
GENERIC_SCHED_CLOCK implementation. We have seen quite some hung tasks in the
past, which seem to be fixed by this patch.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Helge Deller <deller@gmx.de>
The config option HAVE_UNSTABLE_SCHED_CLOCK is set automatically when compiling
for SMP. There is no need to clear the stable-clock flag via
clear_sched_clock_stable() when starting secondary CPUs, and even worse,
clearing it triggers wrong self-detected CPU stall warnings on 64bit Mako
machines.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.7+
Commit 54b6680090 (parisc: Add native high-resolution sched_clock()
implementation) added support to use the CPU-internal cr16 counters as reliable
clocksource with the help of HAVE_UNSTABLE_SCHED_CLOCK.
Sadly the commit missed to remove the hack which prevented cr16 to become the
default clocksource even on SMP systems.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.7+
Pull RTC updates from Alexandre Belloni:
"RTC for 4.8
Cleanups:
- huge cleanup of rtc-generic and char/genrtc this allowed to cleanup
rtc-cmos, rtc-sh, rtc-m68k, rtc-powerpc and rtc-parisc
- move mn10300 to rtc-cmos
Subsystem:
- fix wakealarms after hibernate
- multiples fixes for rctest
- simplify implementations of .read_alarm
New drivers:
- Maxim MAX6916
Drivers:
- ds1307: fix weekday
- m41t80: add wakeup support
- pcf85063: add support for PCF85063A variant
- rv8803: extend i2c fix and other fixes
- s35390a: fix alarm reading, this fixes instant reboot after
shutdown for QNAP TS-41x
- s3c: clock fixes"
* tag 'rtc-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (65 commits)
rtc: rv8803: Clear V1F when setting the time
rtc: rv8803: Stop the clock while setting the time
rtc: rv8803: Always apply the I²C workaround
rtc: rv8803: Fix read day of week
rtc: rv8803: Remove the check for valid time
rtc: rv8803: Kconfig: Indicate rx8900 support
rtc: asm9260: remove .owner field for driver
rtc: at91sam9: Fix missing spin_lock_init()
rtc: m41t80: add suspend handlers for alarm IRQ
rtc: m41t80: make it a real error message
rtc: pcf85063: Add support for the PCF85063A device
rtc: pcf85063: fix year range
rtc: hym8563: in .read_alarm set .tm_sec to 0 to signal minute accuracy
rtc: explicitly set tm_sec = 0 for drivers with minute accurancy
rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq()
rtc: s3c: Remove unnecessary call to disable already disabled clock
rtc: abx80x: use devm_add_action_or_reset()
rtc: m41t80: use devm_add_action_or_reset()
rtc: fix a typo and reduce three empty lines to one
rtc: s35390a: improve two comments in .set_alarm
...
The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and on pa-risc, that is implemented using an open-coded
version of rtc_time_to_tm/rtc_tm_to_time.
This changes the parisc rtc-generic device to provide its
rtc_class_ops directly, using the normal helper functions,
which makes this y2038 safe (on 32-bit) and simplifies
the implementation.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Add a native implementation for the sched_clock() function which utilizes the
processor-internal cycle counter (Control Register 16) as high-resolution time
source.
With this patch we now get much more fine-grained resolutions in various
in-kernel time measurements (e.g. when viewing the function tracing logs), and
probably a more accurate scheduling on SMP systems.
There are a few specific implementation details in this patch:
1. On a 32bit kernel we emulate the higher 32bits of the required 64-bit
resolution of sched_clock() by increasing a per-cpu counter at every
wrap-around of the 32bit cycle counter.
2. In a SMP system, the cycle counters of the various CPUs are not syncronized
(similiar to the TSC in a x86_64 system). To cope with this we define
HAVE_UNSTABLE_SCHED_CLOCK and let the upper layers do the adjustment work.
3. Since we need HAVE_UNSTABLE_SCHED_CLOCK, we need to provide a cmpxchg64()
function even on a 32-bit kernel.
4. A 64-bit SMP kernel which is started on a UP system will mark the
sched_clock() implementation as "stable", which means that we don't expect any
jumps in the returned counter. This is true because we then run only on one
CPU.
Signed-off-by: Helge Deller <deller@gmx.de>
No need to use CONFIG_SMP around update_cr16_clocksource(). It checks for
num_online_cpus() beeing greater than 1, which is always 1 in UP builds.
Signed-off-by: Helge Deller <deller@gmx.de>
This was defined in asm/pdc.h which needs to include asm/page.h for
__PAGE_OFFSET. This leads to an include loop so that page.h eventually will
include pdc.h again. While this is no problem because of header guards, it is
a problem because some symbols may be undefined. Such an error is this:
In file included from include/linux/bitops.h:35:0,
from include/asm-generic/getorder.h:7,
from arch/parisc/include/asm/page.h:162,
from arch/parisc/include/asm/pdc.h:346,
from arch/parisc/include/asm/processor.h:16,
from arch/parisc/include/asm/spinlock.h:6,
from arch/parisc/include/asm/atomic.h:20,
from include/linux/atomic.h:4,
from include/linux/sysfs.h:20,
from include/linux/kobject.h:21,
from include/linux/device.h:17,
from include/linux/eisa.h:5,
from arch/parisc/kernel/pci.c:11:
arch/parisc/include/asm/bitops.h: In function ‘set_bit’:
arch/parisc/include/asm/bitops.h:82:2: error: implicit declaration of function ‘_atomic_spin_lock_irqsave’ [-Werror=implicit-function-declaration]
arch/parisc/include/asm/bitops.h:84:2: error: implicit declaration of function ‘_atomic_spin_unlock_irqrestore’ [-Werror=implicit-function-declaration]
Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This converts the parisc clocksources to use clocksource_register_hz/khz
This is untested, so any assistance in testing would be appreciated!
CC: Kyle McMartin <kyle@mcmartin.ca>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
This patch converts the parisc architecture to use the generic
read_persistent_clock and update_persistent_clock interfaces, reducing
the amount of arch specific code we have to maintain, and allowing for
further cleanups in the future.
I have not built or tested this patch, so help from arch maintainers
would be appreciated.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Rewrote timer_interrupt() to properly handle the "delayed!" case.
If we used floating point math to compute the number of ticks that had
elapsed since the last timer interrupt, it could take up to 12K cycles
(emperical!) to handle the interrupt. Existing code assumed it would
never take more than 8k cycles. We end up programming Interval Timer
to a value less than "current" cycle counter. Thus have to wait until
Interval Timer "wrapped" and would then get the "delayed!" printk that
I moved below.
Since we don't really know what the upper limit is, I prefer to read
CR16 again after we've programmed it to make sure we won't have to
wait for CR16 to wrap.
Further, the printk was between reading CR16 (cycle couner) and writing CR16
(the interval timer). This would cause us to continue to set the interval
timer to a value that was "behind" the cycle counter. Rinse and repeat.
So no printk's between reading CR16 and setting next interval timer.
Tested on A500 (550 Mhz PA8600).
Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Tested-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
----
Kyle, Helge, and other parisc's,
Please test on 32-bit before committing.
I think I have it right but recognize I might not.
TODO: I wanted to use "do_div()" in order to get both remainder
and value back with one division op. That should help with the
latency alot but can be applied seperately from this patch.
thanks,
grant
The rtc-parisc driver is not PA-RISC specific at all, as it uses the existing
(but deprecated) generic RTC infrastructure ([gs]et_rtc_time()).
Rename the driver from rtc-parisc to rtc-generic.
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Helge Deller
Ingo Molnar
Thomas Gleixner
Linus Torvalds
Arnd Bergmann
Rolf Eike Beer
John Stultz
Torben Hohn
Grant Grundler
Coly Li
Geert Uytterhoeven
dann frazier