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The POSIX specification defines that relative CLOCK_REALTIME timers are not
affected by clock modifications. Those timers have to use CLOCK_MONOTONIC
to ensure POSIX compliance.
The introduction of the additional HRTIMER_MODE_PINNED mode broke this
requirement for pinned timers.
There is no user space visible impact because user space timers are not
using pinned mode, but for consistency reasons this needs to be fixed.
Check whether the mode has the HRTIMER_MODE_REL bit set instead of
comparing with HRTIMER_MODE_ABS.
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Fixes: 597d0275736d ("timers: Framework for identifying pinned timers")
Link: http://lkml.kernel.org/r/20171221104205.7269-7-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The hrtimer_start[_range_ns]() functions start a timer reliably on this CPU only
when HRTIMER_MODE_PINNED is set.
Furthermore the HRTIMER_MODE_PINNED mode is not considered when a hrtimer is initialized.
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-6-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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schedule_hrtimeout_range_clock() uses an 'int clock' parameter for the
clock ID, instead of the customary predefined "clockid_t" type.
In hrtimer coding style the canonical variable name for the clock ID is
'clock_id', therefore change the name of the parameter here as well
to make it all consistent.
While at it, clean up the description for the 'clock_id' and 'mode'
function parameters. The clock modes and the clock IDs are not
restricted as the comment suggests.
Fix the mode description as well for the callers of schedule_hrtimeout_range_clock().
No functional changes intended.
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-5-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The '/**' sequence marks the start of a structure description. Add the
missing second asterisk. While at it adapt the ordering of the struct
members to the struct definition and document the purpose of
expires_next more precisely.
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-4-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The protection of a hrtimer which runs its callback against migration to a
different CPU has nothing to do with hard interrupt context.
The protection against migration of a hrtimer running the expiry callback
is the pointer in the cpu_base which holds a pointer to the currently
running timer. This pointer is evaluated in the code which potentially
switches the timer base and makes sure it's kept on the CPU on which the
callback is running.
Reported-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-3-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The hrtimer_cpu_base::migration_enable and ::nohz_active fields
were originally introduced to avoid accessing global variables
for these decisions.
Still that results in a (cache hot) load and conditional branch,
which can be avoided by using static keys.
Implement it with static keys and optimize for the most critical
case of high performance networking which tends to disable the
timer migration functionality.
No change in functionality.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1801142327490.2371@nanos
Link: https://lkml.kernel.org/r/20171221104205.7269-2-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When the timer base is checked for expired timers then the deferrable base
must be checked as well. This was missed when making the deferrable base
independent of base::nohz_active.
Fixes: ced6d5c11d3e ("timers: Use deferrable base independent of base::nohz_active")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
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Because the return value of cpu_timer_sample_group() is not checked,
compilers and static checkers can legitimately warn about a potential use
of the uninitialized variable 'now'. This is not a runtime issue as all call
sites hand in valid clock ids.
Also cpu_timer_sample_group() is invoked unconditionally even when the
result is not used because *oldval is NULL.
Make the invocation conditional and check the return value.
[ tglx: Massage changelog ]
Signed-off-by: Max R. P. Grossmann <m@max.pm>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john.stultz@linaro.org
Link: https://lkml.kernel.org/r/20180108190157.10048-1-m@max.pm
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As we have a lot of timers on this platform, we can have potentially all the
timers enabled in the DT, so we don't want to start the timer for every probe
otherwise they will be running for nothing as only one will be used.
Start the timer only when setting the mode or when the clocksource is
enabled.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-20-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Add the timer delay callback, that saves us ~90ms of boot time.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-19-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The scene is set for the clocksource functionality, let's add it for this driver.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-18-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In order to prepare the clocksource code, let's factor out the clockevent
code, split the prescaler and timer width code into separate functions.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-17-git-send-email-daniel.lezcano@linaro.org
[ Small edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The stm32 timer block is able to have a counter and a comparator.
Instead of using the auto-reload register for periodic events, we switch
to oneshot mode by using the comparator register.
The timer is able to generate an interrupt when the counter overflows but
we don't want that as this counter will be use as a clocksource in the next
patches. So it is disabled by the UDIS bit of the control register.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-16-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The prescaler value is arbitrarily set to 1024 without any regard to the
timer frequency. For 32-bit timers, there is no need to set a prescaler
value as they wrap in an acceptable interval and give the opportunity to
have precise timers on this platform. However, for 16-bit timers a prescaler
value is needed if we don't want to wrap too often per second which is
inefficient and adds more and more error margin. With a targeted clock
of 10MHz, the 16 bits are precise enough whatever the timer frequency is
as we will compute the prescaler.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-15-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In order to clarify and encapsulate the code for upcoming changes, move the
timer width check into a function and add some documentation.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-14-git-send-email-daniel.lezcano@linaro.org
[ Spelling fixes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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As there are different timers on the stm32, use the node name for the timer
name in order to give the indication of which timer the kernel is using.
/proc/timer_list gives all the information with the right name, otherwise
we end up digging in the kernel log and /proc/interrupt to do the connection
between the used timer.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-13-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Convert the driver to use the timer_of() helpers. This allows the removal of
a custom private structure, factors out and simplifies the code.
[Daniel Lezcano]: Respin against the critical fix patch and massaged the changelog.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-12-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The current code hides a couple of bugs:
- The global variable 'clock_event_ddata' is overwritten each time the
init function is invoked.
This is fixed with a kmemdup() instead of assigning the global variable. That
prevents a memory corruption when several timers are defined in the DT.
- The clockevent's event_handler is NULL if the time framework does
not select the clockevent when registering it, this is fine but the init
code generates in any case an interrupt leading to dereference this
NULL pointer.
The stm32 timer works with shadow registers, a mechanism to cache the
registers. When a change is done in one buffered register, we need to
artificially generate an event to force the timer to copy the content
of the register to the shadowed register.
The auto-reload register (ARR) is one of the shadowed register as well as
the prescaler register (PSC), so in order to force the copy, we issue an
event which in turn leads to an interrupt and the NULL dereference.
This is fixed by inverting two lines where we clear the status register
before enabling the update event interrupt.
As this kernel crash is resulting from the combination of these two bugs,
the fixes are grouped into a single patch.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1515418139-23276-11-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When the driver does not specify a name for the resource, don't use
of_io_request_and_map() but of_iomap(). That prevents resource name allocation
conflicts on some platforms which have the same name as the node.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-10-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Under certain circumstances, some specific operations must be done with the
device node pointer, which forces the timer code to propagate the pointer to
the functions which need it.
In order to consolidate the function signatures in the different drivers
by using the timer-of structure, let's store it in the timer-of structure
as a handy pointer when it is needed.
Tested-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-9-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The Spreadtrum SC9860 platform will use the architected timers as local
clock events, but we also need a broadcast timer device to wake up the
CPUs when the CPUs are in sleep mode.
The Spreadtrum timer can support 32-bit or 64-bit counters, as well as
supporting period mode or one-shot mode.
Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-8-git-send-email-daniel.lezcano@linaro.org
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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