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The timer pull model is in place so we can remove the heuristics which try
to guess the best target CPU at enqueue/modification time.
All non pinned timers are queued on the local CPU in the separate storage
and eventually pulled at expiry time to a remote CPU.
Originally-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-21-anna-maria@linutronix.de
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The timer pull logic needs proper debugging aids. Add tracepoints so the
hierarchical idle machinery can be diagnosed.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240222103403.31923-1-anna-maria@linutronix.de
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Placing timers at enqueue time on a target CPU based on dubious heuristics
does not make any sense:
1) Most timer wheel timers are canceled or rearmed before they expire.
2) The heuristics to predict which CPU will be busy when the timer expires
are wrong by definition.
So placing the timers at enqueue wastes precious cycles.
The proper solution to this problem is to always queue the timers on the
local CPU and allow the non pinned timers to be pulled onto a busy CPU at
expiry time.
Therefore split the timer storage into local pinned and global timers:
Local pinned timers are always expired on the CPU on which they have been
queued. Global timers can be expired on any CPU.
As long as a CPU is busy it expires both local and global timers. When a
CPU goes idle it arms for the first expiring local timer. If the first
expiring pinned (local) timer is before the first expiring movable timer,
then no action is required because the CPU will wake up before the first
movable timer expires. If the first expiring movable timer is before the
first expiring pinned (local) timer, then this timer is queued into an idle
timerqueue and eventually expired by another active CPU.
To avoid global locking the timerqueues are implemented as a hierarchy. The
lowest level of the hierarchy holds the CPUs. The CPUs are associated to
groups of 8, which are separated per node. If more than one CPU group
exist, then a second level in the hierarchy collects the groups. Depending
on the size of the system more than 2 levels are required. Each group has a
"migrator" which checks the timerqueue during the tick for remote expirable
timers.
If the last CPU in a group goes idle it reports the first expiring event in
the group up to the next group(s) in the hierarchy. If the last CPU goes
idle it arms its timer for the first system wide expiring timer to ensure
that no timer event is missed.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240222103710.32582-1-anna-maria@linutronix.de
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To prepare for the conversion of the NOHZ timer placement to a pull at
expiry time model it's required to have a function that returns the value
of the is_idle flag of the timer base to keep the hierarchy states during
online in sync with timer base state.
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-18-anna-maria@linutronix.de
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The logic to get the time of the last jiffies update will be needed by
the timer pull model as well.
Move the code into a global function in anticipation of the new caller.
No functional change.
Signed-off-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-17-anna-maria@linutronix.de
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Due to the conversion of the NOHZ timer placement to a pull at expiry
time model, the per CPU timer bases with non pinned timers are no
longer handled only by the local CPU. In case a remote CPU already
expires the non pinned timers base of the local CPU, nothing more
needs to be done by the local CPU. A check at the begin of the expire
timers routine is required, because timer base lock is dropped before
executing the timer callback function.
This is a preparatory work, but has no functional impact right now.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-16-anna-maria@linutronix.de
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Move the locking out from __run_timers() to the call sites, so the
protected section can be extended at the call site. Preparatory work for
changing the NOHZ timer placement to a pull at expiry time model.
No functional change.
Signed-off-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-15-anna-maria@linutronix.de
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To prepare for the conversion of the NOHZ timer placement to a pull at
expiry time model it's required to have functionality available getting the
next timer interrupt on a remote CPU.
Locking of the timer bases and getting the information for the next timer
interrupt functionality is split into separate functions. This is required
to be compliant with lock ordering when the new model is in place.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-14-anna-maria@linutronix.de
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The functionality for getting the next timer interrupt in
get_next_timer_interrupt() is split into a separate function
fetch_next_timer_interrupt() to be usable by other call sites.
This is preparatory work for the conversion of the NOHZ timer
placement to a pull at expiry time model. No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-13-anna-maria@linutronix.de
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For the conversion of the NOHZ timer placement to a pull at expiry time
model it's required to have separate expiry times for the pinned and the
non-pinned (movable) timers. Therefore struct timer_events is introduced.
No functional change
Originally-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-12-anna-maria@linutronix.de
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Separate the storage space for pinned timers. Deferrable timers (doesn't
matter if pinned or non pinned) are still enqueued into their own base.
This is preparatory work for changing the NOHZ timer placement from a push
at enqueue time to a pull at expiry time model.
Originally-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-11-anna-maria@linutronix.de
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Split the logic for getting next timer interrupt (no matter of recalculated
or already stored in base->next_expiry) into a separate function named
next_timer_interrupt(). Make it available to local call sites only.
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-10-anna-maria@linutronix.de
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The logic for raising a softirq the way it is implemented right now, is
readable for two timer bases. When increasing the number of timer bases,
code gets harder to read. With the introduction of the timer migration
hierarchy, there will be three timer bases.
Therefore restructure the code to use a loop. No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-9-anna-maria@linutronix.de
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When adding a timer to the timer wheel using add_timer_on(), it is an
implicitly pinned timer. With the timer pull at expiry time model in place,
the TIMER_PINNED flag is required to make sure timers end up in proper
base.
Set the TIMER_PINNED flag unconditionally when add_timer_on() is executed.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-8-anna-maria@linutronix.de
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The implementation of the NOHZ pull at expiry model will change the timer
bases per CPU. Timers, that have to expire on a specific CPU, require the
TIMER_PINNED flag. If the CPU doesn't matter, the TIMER_PINNED flag must be
dropped. This is required for call sites which use the timer alternately as
pinned and not pinned timer like workqueues do.
Therefore use add_timer_global() in __queue_delayed_work() for non-bound
delayed work to make sure the TIMER_PINNED flag is dropped.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-7-anna-maria@linutronix.de
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A timer might be used as a pinned timer (using add_timer_on()) and later on
as non-pinned timer using add_timer(). When the "NOHZ timer pull at expiry
model" is in place, the TIMER_PINNED flag is required to be used whenever a
timer needs to expire on a dedicated CPU. Otherwise the flag must not be
set if expiration on a dedicated CPU is not required.
add_timer_on()'s behavior will be changed during the preparation patches
for the "NOHZ timer pull at expiry model" to unconditionally set the
TIMER_PINNED flag. To be able to clear/ set the flag when queueing a
timer, two variants of add_timer() are introduced.
This is a preparatory step and has no functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-6-anna-maria@linutronix.de
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When tick is stopped also the timer base is_idle flag is set. When
reentering timer_base_try_to_set_idle() with the tick stopped, there is no
need to check whether the timer base needs to be set idle again. When a
timer was enqueued in the meantime, this is already handled by the
tick_nohz_next_event() call which was executed before
tick_nohz_stop_tick().
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-5-anna-maria@linutronix.de
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The timer base is marked idle when get_next_timer_interrupt() is
executed. But the decision whether the tick will be stopped and whether the
system is able to go idle is done later. When the timer bases is marked
idle and a new first timer is enqueued remote an IPI is raised. Even if it
is not required because the tick is not stopped and the timer base is
evaluated again at the next tick.
To prevent this, the timer base is marked idle in tick_nohz_stop_tick() and
get_next_timer_interrupt() is streamlined by only looking for the next timer
interrupt. All other work is postponed to timer_base_try_to_set_idle() which is
called by tick_nohz_stop_tick(). timer_base_try_to_set_idle() never resets
timer_base::is_idle state. This is done when the tick is restarted via
tick_nohz_restart_sched_tick().
With this, tick_sched::tick_stopped and timer_base::is_idle are always in
sync. So there is no longer the need to execute timer_clear_idle() in
tick_nohz_idle_retain_tick(). This was required before, as
tick_nohz_next_event() set timer_base::is_idle even if the tick would not be
stopped. So timer_clear_idle() is only executed, when timer base is idle. So the
check whether timer base is idle, is now no longer required as well.
While at it fix some nearby whitespace damage as well.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-4-anna-maria@linutronix.de
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Split out get_next_timer_interrupt() to be able to extend it and make it
reusable for other call sites.
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-3-anna-maria@linutronix.de
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get_next_timer_interrupt() contains two parts for the next timer interrupt
calculation. Those two parts are separated by forwarding the base
clock. But the second part does not depend on the forwarded base
clock.
Therefore restructure get_next_timer_interrupt() to keep things together
which belong together.
No functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-2-anna-maria@linutronix.de
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On a 8-socket server the TSC is wrongly marked as 'unstable' and disabled
during boot time on about one out of 120 boot attempts:
clocksource: timekeeping watchdog on CPU227: wd-tsc-wd excessive read-back delay of 153560ns vs. limit of 125000ns,
wd-wd read-back delay only 11440ns, attempt 3, marking tsc unstable
tsc: Marking TSC unstable due to clocksource watchdog
TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'.
sched_clock: Marking unstable (119294969739, 159204297)<-(125446229205, -5992055152)
clocksource: Checking clocksource tsc synchronization from CPU 319 to CPUs 0,99,136,180,210,542,601,896.
clocksource: Switched to clocksource hpet
The reason is that for platform with a large number of CPUs, there are
sporadic big or huge read latencies while reading the watchog/clocksource
during boot or when system is under stress work load, and the frequency and
maximum value of the latency goes up with the number of online CPUs.
The cCurrent code already has logic to detect and filter such high latency
case by reading the watchdog twice and checking the two deltas. Due to the
randomness of the latency, there is a low probabilty that the first delta
(latency) is big, but the second delta is small and looks valid. The
watchdog code retries the readouts by default twice, which is not
necessarily sufficient for systems with a large number of CPUs.
There is a command line parameter 'max_cswd_read_retries' which allows to
increase the number of retries, but that's not user friendly as it needs to
be tweaked per system. As the number of required retries is proportional to
the number of online CPUs, this parameter can be calculated at runtime.
Scale and enlarge the number of retries according to the number of online
CPUs and remove the command line parameter completely.
[ tglx: Massaged change log and comments ]
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jin Wang <jin1.wang@intel.com>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240221060859.1027450-1-feng.tang@intel.com
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'days' is a s64 (from div_s64), and so should use a %lld specifier.
This was found by extending KUnit's assertion macros to use gcc's
__printf attribute.
Fixes: 276010551664 ("time: Improve performance of time64_to_tm()")
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240221092728.1281499-5-davidgow@google.com
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There is already a generic union definition for vdso_data_store in the vdso
datapage header.
Use this definition to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240219153939.75719-11-anna-maria@linutronix.de
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There is already a generic union definition for vdso_data_store in the vdso
datapage header.
Use this definition to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240219153939.75719-10-anna-maria@linutronix.de
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There is already a generic union definition for vdso_data_store in vdso
datapage header.
Use this definition to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240219153939.75719-9-anna-maria@linutronix.de
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There is already a generic union definition for vdso_data_store in the vdso
datapage header.
Use this definition to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20240219153939.75719-8-anna-maria@linutronix.de
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There is already a generic union definition for vdso_data_store in the vdso
datapage header.
Use this definition to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240220085212.6547-1-anna-maria@linutronix.de
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There is already a generic union definition for vdso_data_store in vdso
datapage header.
Use this definition to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240219153939.75719-6-anna-maria@linutronix.de
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The vDSO data page "union vdso_data_store" is defined in an ARM specific
header file and also defined in several other places.
Move the definition from the ARM header file into the generic vdso datapage
header to make it also usable for others and to prevent code duplication.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240219153939.75719-5-anna-maria@linutronix.de
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CSKY selects GENERIC_TIME_VSYSCALL. GENERIC_TIME_VSYSCALL dependent
ifdeffery is superfluous. Clean it up.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20240219153939.75719-4-anna-maria@linutronix.de
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vdso/datapage.h includes the architecture specific vdso/data.h header
file. So there is no need to do it also the other way round and including
the generic vdso/datapage.h header file inside the architecture specific
data.h header file.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20240219153939.75719-3-anna-maria@linutronix.de
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Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240219153939.75719-2-anna-maria@linutronix.de
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There's a conflict between this recent upstream fix:
dad6a09f3148 ("hrtimer: Report offline hrtimer enqueue")
and a pending commit in the timers tree:
1a4729ecafc2 ("hrtimers: Move hrtimer base related definitions into hrtimer_defs.h")
Resolve it by applying the upstream fix to the new <linux/hrtimer_defs.h> header.
Conflict:
include/linux/hrtimer.h
Semantic conflict:
include/linux/hrtimer_defs.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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So far, get_device_system_crosststamp() unconditionally passes
system_counterval.cycles to timekeeping_cycles_to_ns(). But when
interpolating system time (do_interp == true), system_counterval.cycles is
before tkr_mono.cycle_last, contrary to the timekeeping_cycles_to_ns()
expectations.
On x86, CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE will mitigate on
interpolating, setting delta to 0. With delta == 0, xtstamp->sys_monoraw
and xtstamp->sys_realtime are then set to the last update time, as
implicitly expected by adjust_historical_crosststamp(). On other
architectures, the resulting nonsense xtstamp->sys_monoraw and
xtstamp->sys_realtime corrupt the xtstamp (ts) adjustment in
adjust_historical_crosststamp().
Fix this by deriving xtstamp->sys_monoraw and xtstamp->sys_realtime from
the last update time when interpolating, by using the local variable
"cycles". The local variable already has the right value when
interpolating, unlike system_counterval.cycles.
Fixes: 2c756feb18d9 ("time: Add history to cross timestamp interface supporting slower devices")
Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/20231218073849.35294-4-peter.hilber@opensynergy.com
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The cycle_between() helper checks if parameter test is in the open interval
(before, after). Colloquially speaking, this also applies to the counter
wrap-around special case before > after. get_device_system_crosststamp()
currently uses cycle_between() at the first call site to decide whether to
interpolate for older counter readings.
get_device_system_crosststamp() has the following problem with
cycle_between() testing against an open interval: Assume that, by chance,
cycles == tk->tkr_mono.cycle_last (in the following, "cycle_last" for
brevity). Then, cycle_between() at the first call site, with effective
argument values cycle_between(cycle_last, cycles, now), returns false,
enabling interpolation. During interpolation,
get_device_system_crosststamp() will then call cycle_between() at the
second call site (if a history_begin was supplied). The effective argument
values are cycle_between(history_begin->cycles, cycles, cycles), since
system_counterval.cycles == interval_start == cycles, per the assumption.
Due to the test against the open interval, cycle_between() returns false
again. This causes get_device_system_crosststamp() to return -EINVAL.
This failure should be avoided, since get_device_system_crosststamp() works
both when cycles follows cycle_last (no interpolation), and when cycles
precedes cycle_last (interpolation). For the case cycles == cycle_last,
interpolation is actually unneeded.
Fix this by changing cycle_between() into timestamp_in_interval(), which
now checks against the closed interval, rather than the open interval.
This changes the get_device_system_crosststamp() behavior for three corner
cases:
1. Bypass interpolation in the case cycles == tk->tkr_mono.cycle_last,
fixing the problem described above.
2. At the first timestamp_in_interval() call site, cycles == now no longer
causes failure.
3. At the second timestamp_in_interval() call site, history_begin->cycles
== system_counterval.cycles no longer causes failure.
adjust_historical_crosststamp() also works for this corner case,
where partial_history_cycles == total_history_cycles.
These behavioral changes should not cause any problems.
Fixes: 2c756feb18d9 ("time: Add history to cross timestamp interface supporting slower devices")
Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20231218073849.35294-3-peter.hilber@opensynergy.com
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cycle_between() decides whether get_device_system_crosststamp() will
interpolate for older counter readings.
cycle_between() yields wrong results for a counter wrap-around where after
< before < test, and for the case after < test < before.
Fix the comparison logic.
Fixes: 2c756feb18d9 ("time: Add history to cross timestamp interface supporting slower devices")
Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/20231218073849.35294-2-peter.hilber@opensynergy.com
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This general note about time_* functions is also useful to be available in
kernel documentation. Therefore transform it into a kernel-doc DOC block
with proper formatting.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240123164702.55612-6-anna-maria@linutronix.de
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timer_base struct lacks description of struct members. Important struct
member information is sprinkled in comments or in code all over the place.
Collect information and write struct description to keep track of most
important information in a single place.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240123164702.55612-5-anna-maria@linutronix.de
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The return value of tick_nohz_next_event() is not obvious at the first
glance. Add a kernel-doc compatible function description which also covers
return values.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240123164702.55612-4-anna-maria@linutronix.de
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Documentation of functions lacks the annotations which are used by
kernel-doc and *.rst to make appearance in rendered documents more
user-friendly.
Use those annotations to improve user-friendliness. While at it prevent
duplication of comments and use a reference instead.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240123164702.55612-3-anna-maria@linutronix.de
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hrtimer base related struct definitions are part of hrtimers.h as it is
required there. With this, also the struct documentation which is for core
code internal use, is exposed into the general api.
To prevent this, move all core internal definitions and the related
includes into hrtimer_defs.h.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240123164702.55612-2-anna-maria@linutronix.de
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- Reformat nested if-conditionals in Makefiles with 4 spaces
- Fix CONFIG_DEBUG_INFO_BTF builds for big endian
- Fix modpost for module srcversion
- Fix an escape sequence warning in gen_compile_commands.py
- Fix kallsyms to ignore ARMv4 thunk symbols
* tag 'kbuild-fixes-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kallsyms: ignore ARMv4 thunks along with others
modpost: trim leading spaces when processing source files list
gen_compile_commands: fix invalid escape sequence warning
kbuild: Fix changing ELF file type for output of gen_btf for big endian
docs: kconfig: Fix grammar and formatting
kbuild: use 4-space indentation when followed by conditionals
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
- Use a GB page for identity mapping only when memory of this size is
requested so that mapping of reserved regions is prevented which
would otherwise lead to system crashes on UV machines
* tag 'x86_urgent_for_v6.8_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Borislav Petkov:
- Fix GICv4.1 affinity update
- Restore a quirk for ACPI-based GICv4 systems
- Handle non-coherent GICv4 redistributors properly
- Prevent spurious interrupts on Broadcom devices using GIC v3
architecture
- Other minor fixes
* tag 'irq_urgent_for_v6.8_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/gic-v3-its: Fix GICv4.1 VPE affinity update
irqchip/gic-v3-its: Restore quirk probing for ACPI-based systems
irqchip/gic-v3-its: Handle non-coherent GICv4 redistributors
irqchip/qcom-mpm: Fix IS_ERR() vs NULL check in qcom_mpm_init()
irqchip/loongson-eiointc: Use correct struct type in eiointc_domain_alloc()
irqchip/irq-brcmstb-l2: Add write memory barrier before exit
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
"Two fixes for i801 and qcom-geni devices. Meanwhile, a fix from Arnd
addresses a compilation error encountered during compile test on
powerpc"
* tag 'i2c-for-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: i801: Fix block process call transactions
i2c: pasemi: split driver into two separate modules
i2c: qcom-geni: Correct I2C TRE sequence
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"This is a bit of a big batch for rc4, but just due to holiday hangover
and because I didn't send any fixes last week due to a late revert
request. I think next week should be back to normal.
- Fix ftrace bug on boot caused by exit text sections with
'-fpatchable-function-entry'
- Fix accuracy of stolen time on pseries since the switch to
VIRT_CPU_ACCOUNTING_GEN
- Fix a crash in the IOMMU code when doing DLPAR remove
- Set pt_regs->link on scv entry to fix BPF stack unwinding
- Add missing PPC_FEATURE_BOOKE on 64-bit e5500/e6500, which broke
gdb
- Fix boot on some 6xx platforms with STRICT_KERNEL_RWX enabled
- Fix build failures with KASAN enabled and 32KB stack size
- Some other minor fixes
Thanks to Arnd Bergmann, Benjamin Gray, Christophe Leroy, David
Engraf, Gaurav Batra, Jason Gunthorpe, Jiangfeng Xiao, Matthias
Schiffer, Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nysal Jan K.A,
R Nageswara Sastry, Shivaprasad G Bhat, Shrikanth Hegde, Spoorthy,
Srikar Dronamraju, and Venkat Rao Bagalkote"
* tag 'powerpc-6.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/iommu: Fix the missing iommu_group_put() during platform domain attach
powerpc/pseries: fix accuracy of stolen time
powerpc/ftrace: Ignore ftrace locations in exit text sections
powerpc/cputable: Add missing PPC_FEATURE_BOOKE on PPC64 Book-E
powerpc/kasan: Limit KASAN thread size increase to 32KB
Revert "powerpc/pseries/iommu: Fix iommu initialisation during DLPAR add"
powerpc: 85xx: mark local functions static
powerpc: udbg_memcons: mark functions static
powerpc/kasan: Fix addr error caused by page alignment
powerpc/6xx: set High BAT Enable flag on G2_LE cores
selftests/powerpc/papr_vpd: Check devfd before get_system_loc_code()
powerpc/64: Set task pt_regs->link to the LR value on scv entry
powerpc/pseries/iommu: Fix iommu initialisation during DLPAR add
powerpc/pseries/papr-sysparm: use u8 arrays for payloads
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Pull bcachefs fixes from Kent Overstreet:
"Mostly pretty trivial, the user visible ones are:
- don't barf when replicas_required > replicas
- fix check_version_upgrade() so it doesn't do something nonsensical
when we're downgrading"
* tag 'bcachefs-2024-02-17' of https://evilpiepirate.org/git/bcachefs:
bcachefs: Fix missing va_end()
bcachefs: Fix check_version_upgrade()
bcachefs: Clamp replicas_required to replicas
bcachefs: fix missing endiannes conversion in sb_members
bcachefs: fix kmemleak in __bch2_read_super error handling path
bcachefs: Fix missing bch2_err_class() calls
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH:
"Here are some driver core fixes, a kobject fix, and a documentation
update for 6.8-rc5. In detail these changes are:
- devlink fixes for reported issues with 6.8-rc1
- topology scheduling regression fix that has been reported by many
- kobject loosening of checks change in -rc1 is now reverted as some
codepaths seemed to need the checks
- documentation update for the CVE process. Has been reviewed by
many, the last minute change to the document was to bring the .rst
format back into the the new style rules, the contents did not
change.
All of these, except for the documentation update, have been in
linux-next for over a week. The documentation update has been reviewed
for weeks by a group of developers, and in public for a week and the
wording has stabilized for now. If future changes are needed, we can
do so before 6.8-final is out (or anytime after that)"
* tag 'driver-core-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
Documentation: Document the Linux Kernel CVE process
Revert "kobject: Remove redundant checks for whether ktype is NULL"
driver core: fw_devlink: Improve logs for cycle detection
driver core: fw_devlink: Improve detection of overlapping cycles
driver core: Fix device_link_flag_is_sync_state_only()
topology: Set capacity_freq_ref in all cases
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / miscdriver fixes from Greg KH:
"Here is a small set of char/misc and IIO driver fixes for 6.8-rc5.
Included in here are:
- lots of iio driver fixes for reported issues
- nvmem device naming fixup for reported problem
- interconnect driver fixes for reported issues
All of these have been in linux-next for a while with no reported the
issues (the nvmem patch was included in a different branch in
linux-next before sent to me for inclusion here)"
* tag 'char-misc-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (21 commits)
nvmem: include bit index in cell sysfs file name
iio: adc: ad4130: only set GPIO_CTRL if pin is unused
iio: adc: ad4130: zero-initialize clock init data
interconnect: qcom: x1e80100: Add missing ACV enable_mask
interconnect: qcom: sm8650: Use correct ACV enable_mask
iio: accel: bma400: Fix a compilation problem
iio: commom: st_sensors: ensure proper DMA alignment
iio: hid-sensor-als: Return 0 for HID_USAGE_SENSOR_TIME_TIMESTAMP
iio: move LIGHT_UVA and LIGHT_UVB to the end of iio_modifier
staging: iio: ad5933: fix type mismatch regression
iio: humidity: hdc3020: fix temperature offset
iio: adc: ad7091r8: Fix error code in ad7091r8_gpio_setup()
iio: adc: ad_sigma_delta: ensure proper DMA alignment
iio: imu: adis: ensure proper DMA alignment
iio: humidity: hdc3020: Add Makefile, Kconfig and MAINTAINERS entry
iio: imu: bno055: serdev requires REGMAP
iio: magnetometer: rm3100: add boundary check for the value read from RM3100_REG_TMRC
iio: pressure: bmp280: Add missing bmp085 to SPI id table
iio: core: fix memleak in iio_device_register_sysfs
interconnect: qcom: sm8550: Enable sync_state
...
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