kernel.git/arch/s390/kernel/time.c, branch linux-4.14.y

s390/stp: add locking to sysfs functions

2020-11-05T10:07:02Z

commit b3bd02495cb339124f13135d51940cf48d83e5cb upstream. The sysfs function might race with stp_work_fn. To prevent that, add the required locking. Another issue is that the sysfs functions are checking the stp_online flag, but this flag just holds the user setting whether STP is enabled. Add a flag to clock_sync_flag whether stp_info holds valid data and use that instead. Cc: stable@vger.kernel.org Signed-off-by: Sven Schnelle Reviewed-by: Alexander Egorenkov Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/dasd: Change unsigned long long to unsigned long

2017-08-23T11:31:51Z

Unsigned long long and unsigned long were different in size for 31-bit. For 64-bit the size for both datatypes is 8 Bytes and since the support for 31-bit is long gone we can clean up a little and change everything to unsigned long. Change get_phys_clock() along the way to accept unsigned long as well so that the DASD code can be consistent. Acked-by: Heiko Carstens Signed-off-by: Jan Höppner Signed-off-by: Martin Schwidefsky

s390/time: add support for the TOD clock epoch extension

2017-07-26T06:25:14Z

The TOD epoch extension adds 8 epoch bits to the TOD clock to provide a continuous clock after 2042/09/17. The store-clock-extended (STCKE) instruction will store the epoch index in the first byte of the 16 bytes stored by the instruction. The read_boot_clock64 and the read_presistent_clock64 functions need to take the additional bits into account to give the correct result after 2042/09/17. The clock-comparator register will stay 64 bit wide. The comparison of the clock-comparator with the TOD clock is limited to bytes 1 to 8 of the extended TOD format. To deal with the overflow problem due to an epoch change the clock-comparator sign control in CR0 can be used to switch the comparison of the 64-bit TOD clock with the clock-comparator to a signed comparison. The decision between the signed vs. unsigned clock-comparator comparisons is done at boot time. Only if the TOD clock is in the second half of a 142 year epoch the signed comparison is used. This solves the epoch overflow issue as long as the machine is booted at least once in an epoch. Signed-off-by: Martin Schwidefsky

s390/kernel: Use stop_machine_cpuslocked()

2017-05-26T08:10:41Z

stp_work_fn() holds get_online_cpus() while invoking stop_machine(). stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use stop_machine_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Acked-by: Heiko Carstens Cc: Paul E. McKenney Cc: linux-s390@vger.kernel.org Cc: Peter Zijlstra Cc: Steven Rostedt Cc: David Hildenbrand Cc: Martin Schwidefsky Link: http://lkml.kernel.org/r/20170524081548.250203087@linutronix.de

s390/time: Set ->min_delta_ticks and ->max_delta_ticks

2017-04-14T20:11:20Z

In preparation for making the clockevents core NTP correction aware, all clockevent device drivers must set ->min_delta_ticks and ->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a clockevent device's rate is going to change dynamically and thus, the ratio of ns to ticks ceases to stay invariant. Currently, the s390's CPU timer clockevent device is initialized as follows: cd->min_delta_ns = 1; cd->max_delta_ns = LONG_MAX; Note that the device's time to cycle conversion factor, i.e. cd->mult / (2^cd->shift), is approx. equal to 4. Hence, this would translate to cd->min_delta_ticks = 4; cd->max_delta_ticks = 4 * LONG_MAX; However, a minimum value of 1ns is in the range of noise anyway and the clockevent core will take care of this by increasing it to 1us or so. Furthermore, 4*LONG_MAX would overflow the unsigned long argument the clockevent devices gets programmed with. Thus, initialize ->min_delta_ticks with 1 and ->max_delta_ticks with ULONG_MAX. This patch alone doesn't introduce any change in functionality as the clockevents core still looks exclusively at the (untouched) ->min_delta_ns and ->max_delta_ns. As soon as this has changed, a followup patch will purge the initialization of ->min_delta_ns and ->max_delta_ns from this driver. Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Daniel Lezcano Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: David Hildenbrand Cc: linux-s390@vger.kernel.org Signed-off-by: Nicolai Stange Signed-off-by: John Stultz

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:27Z

We are going to split out of , which will have to be picked up from other headers and .c files. Create a trivial placeholder file that just maps to 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 Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

s390: kernel: Audit and remove any unnecessary uses of module.h

2017-02-17T06:40:31Z

Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. The advantage in doing so is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each change instance for the presence of either and replace as needed. Build testing revealed some implicit header usage that was fixed up accordingly. Signed-off-by: Paul Gortmaker Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390/debug: make debug event time stamps relative to the boot TOD clock

2017-02-07T06:27:13Z

The debug features currently uses absolute TOD time stamps for the debug events. Given that the TOD clock can jump forward and backward due to STP sync checks the order of debug events can get obfuscated. Replace the absolute TOD time stamps with a delta to the IPL time stamp. On a STP sync check the TOD clock correction is added to the IPL time stamp as well to make the deltas unaffected by STP sync check. The readout of the debug feature entries will convert the deltas back to absolute time stamps based on the Unix epoch. Signed-off-by: Martin Schwidefsky

s390: use false/true when using bool

2017-01-16T06:27:54Z

Yet another trivial patch to reduce the noise that coccinelle generates. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

clocksource: Use a plain u64 instead of cycle_t

2016-12-25T10:04:12Z

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 Cc: Peter Zijlstra Cc: John Stultz