Commit Graph

168 Commits

Author SHA1 Message Date
Jason A. Donenfeld
81895a65ec treewide: use prandom_u32_max() when possible, part 1
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

-       RAND = get_random_u32();
        ... when != RAND
-       RAND %= (E);
+       RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
        print("Skipping 0x%x for cleanup elsewhere" % (value))
        cocci.include_match(False)
elif value & (value + 1) != 0:
        print("Skipping 0x%x because it's not a power of two minus one" % (value))
        cocci.include_match(False)
elif literal.startswith('0x'):
        coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
        coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

 {
-       T VAR;
-       VAR = (E);
-       return VAR;
+       return E;
 }

@drop_var@
type T;
identifier VAR;
@@

 {
-       T VAR;
        ... when != VAR
 }

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:55 -06:00
Yury Norov
8afbcaf869 clocksource: Replace cpumask_weight() with cpumask_empty()
clocksource_verify_percpu() calls cpumask_weight() to check if any bit of a
given cpumask is set.

This can be done more efficiently with cpumask_empty() because
cpumask_empty() stops traversing the cpumask as soon as it finds first set
bit, while cpumask_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220210224933.379149-24-yury.norov@gmail.com
2022-04-10 22:30:04 +02:00
Waiman Long
fc153c1c58 clocksource: Add a Kconfig option for WATCHDOG_MAX_SKEW
A watchdog maximum skew of 100us may still be too small for
some systems or archs. It may also be too small when some kernel
debug config options are enabled.  So add a new Kconfig option
CLOCKSOURCE_WATCHDOG_MAX_SKEW_US to allow kernel builders to have more
control on the threshold for marking clocksource as unstable.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-02-01 17:35:43 -08:00
Linus Torvalds
3689f9f8b0 bitmap patches for 5.17-rc1
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Merge tag 'bitmap-5.17-rc1' of git://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - introduce for_each_set_bitrange()

 - use find_first_*_bit() instead of find_next_*_bit() where possible

 - unify for_each_bit() macros

* tag 'bitmap-5.17-rc1' of git://github.com/norov/linux:
  vsprintf: rework bitmap_list_string
  lib: bitmap: add performance test for bitmap_print_to_pagebuf
  bitmap: unify find_bit operations
  mm/percpu: micro-optimize pcpu_is_populated()
  Replace for_each_*_bit_from() with for_each_*_bit() where appropriate
  find: micro-optimize for_each_{set,clear}_bit()
  include/linux: move for_each_bit() macros from bitops.h to find.h
  cpumask: replace cpumask_next_* with cpumask_first_* where appropriate
  tools: sync tools/bitmap with mother linux
  all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate
  cpumask: use find_first_and_bit()
  lib: add find_first_and_bit()
  arch: remove GENERIC_FIND_FIRST_BIT entirely
  include: move find.h from asm_generic to linux
  bitops: move find_bit_*_le functions from le.h to find.h
  bitops: protect find_first_{,zero}_bit properly
2022-01-23 06:20:44 +02:00
Yury Norov
9b51d9d866 cpumask: replace cpumask_next_* with cpumask_first_* where appropriate
cpumask_first() is a more effective analogue of 'next' version if n == -1
(which means start == 0). This patch replaces 'next' with 'first' where
things look trivial.

There's no cpumask_first_zero() function, so create it.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
2022-01-15 08:47:31 -08:00
Waiman Long
1a5620671a clocksource: Reduce the default clocksource_watchdog() retries to 2
With the previous patch, there is an extra watchdog read in each retry.
Now the total number of clocksource reads is increased to 4 per iteration.
In order to avoid increasing the clock skew check overhead, the default
maximum number of retries is reduced from 3 to 2 to maintain the same 12
clocksource reads in the worst case.

Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-11-30 17:22:29 -08:00
Waiman Long
c86ff8c55b clocksource: Avoid accidental unstable marking of clocksources
Since commit db3a34e174 ("clocksource: Retry clock read if long delays
detected") and commit 2e27e793e2 ("clocksource: Reduce clocksource-skew
threshold"), it is found that tsc clocksource fallback to hpet can
sometimes happen on both Intel and AMD systems especially when they are
running stressful benchmarking workloads. Of the 23 systems tested with
a v5.14 kernel, 10 of them have switched to hpet clock source during
the test run.

The result of falling back to hpet is a drastic reduction of performance
when running benchmarks. For example, the fio performance tests can
drop up to 70% whereas the iperf3 performance can drop up to 80%.

4 hpet fallbacks happened during bootup. They were:

  [    8.749399] clocksource: timekeeping watchdog on CPU13: hpet read-back delay of 263750ns, attempt 4, marking unstable
  [   12.044610] clocksource: timekeeping watchdog on CPU19: hpet read-back delay of 186166ns, attempt 4, marking unstable
  [   17.336941] clocksource: timekeeping watchdog on CPU28: hpet read-back delay of 182291ns, attempt 4, marking unstable
  [   17.518565] clocksource: timekeeping watchdog on CPU34: hpet read-back delay of 252196ns, attempt 4, marking unstable

Other fallbacks happen when the systems were running stressful
benchmarks. For example:

  [ 2685.867873] clocksource: timekeeping watchdog on CPU117: hpet read-back delay of 57269ns, attempt 4, marking unstable
  [46215.471228] clocksource: timekeeping watchdog on CPU8: hpet read-back delay of 61460ns, attempt 4, marking unstable

Commit 2e27e793e2 ("clocksource: Reduce clocksource-skew threshold"),
changed the skew margin from 100us to 50us. I think this is too small
and can easily be exceeded when running some stressful workloads on a
thermally stressed system.  So it is switched back to 100us.

Even a maximum skew margin of 100us may be too small in for some systems
when booting up especially if those systems are under thermal stress. To
eliminate the case that the large skew is due to the system being too
busy slowing down the reading of both the watchdog and the clocksource,
an extra consecutive read of watchdog clock is being done to check this.

The consecutive watchdog read delay is compared against
WATCHDOG_MAX_SKEW/2. If the delay exceeds the limit, we assume that
the system is just too busy. A warning will be printed to the console
and the clock skew check is skipped for this round.

Fixes: db3a34e174 ("clocksource: Retry clock read if long delays detected")
Fixes: 2e27e793e2 ("clocksource: Reduce clocksource-skew threshold")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-11-30 17:22:29 -08:00
Sebastian Andrzej Siewior
698429f9d0 clocksource: Replace deprecated CPU-hotplug functions.
The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-35-bigeasy@linutronix.de
2021-08-10 14:53:58 +02:00
Feng Tang
22a2238337 clocksource: Print deviation in nanoseconds when a clocksource becomes unstable
Currently when an unstable clocksource is detected, the raw counters of
that clocksource and watchdog will be printed, which can only be understood
after some math calculation.

So print the delta in nanoseconds as well to make it easier for humans to
check the results.

[ paulmck: Fix typo. ]

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210527190124.440372-6-paulmck@kernel.org
2021-06-22 16:53:17 +02:00
Paul E. McKenney
1253b9b87e clocksource: Provide kernel module to test clocksource watchdog
When the clocksource watchdog marks a clock as unstable, this might
be due to that clock being unstable or it might be due to delays that
happen to occur between the reads of the two clocks.  It would be good
to have a way of testing the clocksource watchdog's ability to
distinguish between these two causes of clock skew and instability.

Therefore, provide a new clocksource-wdtest module selected by a new
TEST_CLOCKSOURCE_WATCHDOG Kconfig option.  This module has a single module
parameter named "holdoff" that provides the number of seconds of delay
before testing should start, which defaults to zero when built as a module
and to 10 seconds when built directly into the kernel.  Very large systems
that boot slowly may need to increase the value of this module parameter.

This module uses hand-crafted clocksource structures to do its testing,
thus avoiding messing up timing for the rest of the kernel and for user
applications.  This module first verifies that the ->uncertainty_margin
field of the clocksource structures are set sanely.  It then tests the
delay-detection capability of the clocksource watchdog, increasing the
number of consecutive delays injected, first provoking console messages
complaining about the delays and finally forcing a clock-skew event.
Unexpected test results cause at least one WARN_ON_ONCE() console splat.
If there are no splats, the test has passed.  Finally, it fuzzes the
value returned from a clocksource to test the clocksource watchdog's
ability to detect time skew.

This module checks the state of its clocksource after each test, and
uses WARN_ON_ONCE() to emit a console splat if there are any failures.
This should enable all types of test frameworks to detect any such
failures.

This facility is intended for diagnostic use only, and should be avoided
on production systems.

Reported-by: Chris Mason <clm@fb.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Feng Tang <feng.tang@intel.com>
Link: https://lore.kernel.org/r/20210527190124.440372-5-paulmck@kernel.org
2021-06-22 16:53:17 +02:00
Paul E. McKenney
2e27e793e2 clocksource: Reduce clocksource-skew threshold
Currently, WATCHDOG_THRESHOLD is set to detect a 62.5-millisecond skew in
a 500-millisecond WATCHDOG_INTERVAL.  This requires that clocks be skewed
by more than 12.5% in order to be marked unstable.  Except that a clock
that is skewed by that much is probably destroying unsuspecting software
right and left.  And given that there are now checks for false-positive
skews due to delays between reading the two clocks, it should be possible
to greatly decrease WATCHDOG_THRESHOLD, at least for fine-grained clocks
such as TSC.

Therefore, add a new uncertainty_margin field to the clocksource structure
that contains the maximum uncertainty in nanoseconds for the corresponding
clock.  This field may be initialized manually, as it is for
clocksource_tsc_early and clocksource_jiffies, which is copied to
refined_jiffies.  If the field is not initialized manually, it will be
computed at clock-registry time as the period of the clock in question
based on the scale and freq parameters to __clocksource_update_freq_scale()
function.  If either of those two parameters are zero, the
tens-of-milliseconds WATCHDOG_THRESHOLD is used as a cowardly alternative
to dividing by zero.  No matter how the uncertainty_margin field is
calculated, it is bounded below by twice WATCHDOG_MAX_SKEW, that is, by 100
microseconds.

Note that manually initialized uncertainty_margin fields are not adjusted,
but there is a WARN_ON_ONCE() that triggers if any such field is less than
twice WATCHDOG_MAX_SKEW.  This WARN_ON_ONCE() is intended to discourage
production use of the one-nanosecond uncertainty_margin values that are
used to test the clock-skew code itself.

The actual clock-skew check uses the sum of the uncertainty_margin fields
of the two clocksource structures being compared.  Integer overflow is
avoided because the largest computed value of the uncertainty_margin
fields is one billion (10^9), and double that value fits into an
unsigned int.  However, if someone manually specifies (say) UINT_MAX,
they will get what they deserve.

Note that the refined_jiffies uncertainty_margin field is initialized to
TICK_NSEC, which means that skew checks involving this clocksource will
be sufficently forgiving.  In a similar vein, the clocksource_tsc_early
uncertainty_margin field is initialized to 32*NSEC_PER_MSEC, which
replicates the current behavior and allows custom setting if needed
in order to address the rare skews detected for this clocksource in
current mainline.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Feng Tang <feng.tang@intel.com>
Link: https://lore.kernel.org/r/20210527190124.440372-4-paulmck@kernel.org
2021-06-22 16:53:16 +02:00
Paul E. McKenney
fa218f1cce clocksource: Limit number of CPUs checked for clock synchronization
Currently, if skew is detected on a clock marked CLOCK_SOURCE_VERIFY_PERCPU,
that clock is checked on all CPUs.  This is thorough, but might not be
what you want on a system with a few tens of CPUs, let alone a few hundred
of them.

Therefore, by default check only up to eight randomly chosen CPUs.  Also
provide a new clocksource.verify_n_cpus kernel boot parameter.  A value of
-1 says to check all of the CPUs, and a non-negative value says to randomly
select that number of CPUs, without concern about selecting the same CPU
multiple times.  However, make use of a cpumask so that a given CPU will be
checked at most once.

Suggested-by: Thomas Gleixner <tglx@linutronix.de> # For verify_n_cpus=1.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Feng Tang <feng.tang@intel.com>
Link: https://lore.kernel.org/r/20210527190124.440372-3-paulmck@kernel.org
2021-06-22 16:53:16 +02:00
Paul E. McKenney
7560c02bdf clocksource: Check per-CPU clock synchronization when marked unstable
Some sorts of per-CPU clock sources have a history of going out of
synchronization with each other.  However, this problem has purportedy been
solved in the past ten years.  Except that it is all too possible that the
problem has instead simply been made less likely, which might mean that
some of the occasional "Marking clocksource 'tsc' as unstable" messages
might be due to desynchronization.  How would anyone know?

Therefore apply CPU-to-CPU synchronization checking to newly unstable
clocksource that are marked with the new CLOCK_SOURCE_VERIFY_PERCPU flag.
Lists of desynchronized CPUs are printed, with the caveat that if it
is the reporting CPU that is itself desynchronized, it will appear that
all the other clocks are wrong.  Just like in real life.

Reported-by: Chris Mason <clm@fb.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Feng Tang <feng.tang@intel.com>
Link: https://lore.kernel.org/r/20210527190124.440372-2-paulmck@kernel.org
2021-06-22 16:53:16 +02:00
Paul E. McKenney
db3a34e174 clocksource: Retry clock read if long delays detected
When the clocksource watchdog marks a clock as unstable, this might be due
to that clock being unstable or it might be due to delays that happen to
occur between the reads of the two clocks.  Yes, interrupts are disabled
across those two reads, but there are no shortage of things that can delay
interrupts-disabled regions of code ranging from SMI handlers to vCPU
preemption.  It would be good to have some indication as to why the clock
was marked unstable.

Therefore, re-read the watchdog clock on either side of the read from the
clock under test.  If the watchdog clock shows an excessive time delta
between its pair of reads, the reads are retried.

The maximum number of retries is specified by a new kernel boot parameter
clocksource.max_cswd_read_retries, which defaults to three, that is, up to
four reads, one initial and up to three retries.  If more than one retry
was required, a message is printed on the console (the occasional single
retry is expected behavior, especially in guest OSes).  If the maximum
number of retries is exceeded, the clock under test will be marked
unstable.  However, the probability of this happening due to various sorts
of delays is quite small.  In addition, the reason (clock-read delays) for
the unstable marking will be apparent.

Reported-by: Chris Mason <clm@fb.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Feng Tang <feng.tang@intel.com>
Link: https://lore.kernel.org/r/20210527190124.440372-1-paulmck@kernel.org
2021-06-22 16:53:16 +02:00
Linus Torvalds
152d32aa84 ARM:
- Stage-2 isolation for the host kernel when running in protected mode
 
 - Guest SVE support when running in nVHE mode
 
 - Force W^X hypervisor mappings in nVHE mode
 
 - ITS save/restore for guests using direct injection with GICv4.1
 
 - nVHE panics now produce readable backtraces
 
 - Guest support for PTP using the ptp_kvm driver
 
 - Performance improvements in the S2 fault handler
 
 x86:
 
 - Optimizations and cleanup of nested SVM code
 
 - AMD: Support for virtual SPEC_CTRL
 
 - Optimizations of the new MMU code: fast invalidation,
   zap under read lock, enable/disably dirty page logging under
   read lock
 
 - /dev/kvm API for AMD SEV live migration (guest API coming soon)
 
 - support SEV virtual machines sharing the same encryption context
 
 - support SGX in virtual machines
 
 - add a few more statistics
 
 - improved directed yield heuristics
 
 - Lots and lots of cleanups
 
 Generic:
 
 - Rework of MMU notifier interface, simplifying and optimizing
 the architecture-specific code
 
 - Some selftests improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "This is a large update by KVM standards, including AMD PSP (Platform
  Security Processor, aka "AMD Secure Technology") and ARM CoreSight
  (debug and trace) changes.

  ARM:

   - CoreSight: Add support for ETE and TRBE

   - Stage-2 isolation for the host kernel when running in protected
     mode

   - Guest SVE support when running in nVHE mode

   - Force W^X hypervisor mappings in nVHE mode

   - ITS save/restore for guests using direct injection with GICv4.1

   - nVHE panics now produce readable backtraces

   - Guest support for PTP using the ptp_kvm driver

   - Performance improvements in the S2 fault handler

  x86:

   - AMD PSP driver changes

   - Optimizations and cleanup of nested SVM code

   - AMD: Support for virtual SPEC_CTRL

   - Optimizations of the new MMU code: fast invalidation, zap under
     read lock, enable/disably dirty page logging under read lock

   - /dev/kvm API for AMD SEV live migration (guest API coming soon)

   - support SEV virtual machines sharing the same encryption context

   - support SGX in virtual machines

   - add a few more statistics

   - improved directed yield heuristics

   - Lots and lots of cleanups

  Generic:

   - Rework of MMU notifier interface, simplifying and optimizing the
     architecture-specific code

   - a handful of "Get rid of oprofile leftovers" patches

   - Some selftests improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (379 commits)
  KVM: selftests: Speed up set_memory_region_test
  selftests: kvm: Fix the check of return value
  KVM: x86: Take advantage of kvm_arch_dy_has_pending_interrupt()
  KVM: SVM: Skip SEV cache flush if no ASIDs have been used
  KVM: SVM: Remove an unnecessary prototype declaration of sev_flush_asids()
  KVM: SVM: Drop redundant svm_sev_enabled() helper
  KVM: SVM: Move SEV VMCB tracking allocation to sev.c
  KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup()
  KVM: SVM: Unconditionally invoke sev_hardware_teardown()
  KVM: SVM: Enable SEV/SEV-ES functionality by default (when supported)
  KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y
  KVM: SVM: Append "_enabled" to module-scoped SEV/SEV-ES control variables
  KVM: SEV: Mask CPUID[0x8000001F].eax according to supported features
  KVM: SVM: Move SEV module params/variables to sev.c
  KVM: SVM: Disable SEV/SEV-ES if NPT is disabled
  KVM: SVM: Free sev_asid_bitmap during init if SEV setup fails
  KVM: SVM: Zero out the VMCB array used to track SEV ASID association
  x86/sev: Drop redundant and potentially misleading 'sev_enabled'
  KVM: x86: Move reverse CPUID helpers to separate header file
  KVM: x86: Rename GPR accessors to make mode-aware variants the defaults
  ...
2021-05-01 10:14:08 -07:00
Thomas Gleixner
b2c67cbe9f time: Add mechanism to recognize clocksource in time_get_snapshot
System time snapshots are not conveying information about the current
clocksource which was used, but callers like the PTP KVM guest
implementation have the requirement to evaluate the clocksource type to
select the appropriate mechanism.

Introduce a clocksource id field in struct clocksource which is by default
set to CSID_GENERIC (0). Clocksource implementations can set that field to
a value which allows to identify the clocksource.

Store the clocksource id of the current clocksource in the
system_time_snapshot so callers can evaluate which clocksource was used to
take the snapshot and act accordingly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-5-jianyong.wu@arm.com
2021-04-07 16:33:20 +01:00
Ingo Molnar
4bf07f6562 timekeeping, clocksource: Fix various typos in comments
Fix ~56 single-word typos in timekeeping & clocksource code comments.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-kernel@vger.kernel.org
2021-03-22 23:06:48 +01:00
Arnd Bergmann
77f6c0b874 timekeeping: remove arch_gettimeoffset
With Arm EBSA110 gone, nothing uses it any more, so the corresponding
code and the Kconfig option can be removed.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2020-10-30 21:57:04 +01:00
Thomas Gleixner
c7f3d43b62 clocksource: Remove obsolete ifdef
CONFIG_GENERIC_VDSO_CLOCK_MODE was a transitional config switch which got
removed after all architectures got converted to the new storage model.

But the removal forgot to remove the #ifdef which guards the
vdso_clock_mode sanity check, which effectively disables the sanity check.

Remove it now.

Fixes: f86fd32db7 ("lib/vdso: Cleanup clock mode storage leftovers")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200606221531.845475036@linutronix.de
2020-06-09 16:36:47 +02:00
Thomas Gleixner
5d51bee725 clocksource: Add common vdso clock mode storage
All architectures which use the generic VDSO code have their own storage
for the VDSO clock mode. That's pointless and just requires duplicate code.

Provide generic storage for it. The new Kconfig symbol is intermediate and
will be removed once all architectures are converted over.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.028046322@linutronix.de
2020-02-17 14:40:23 +01:00
Konstantin Khlebnikov
febac332a8 clocksource: Prevent double add_timer_on() for watchdog_timer
Kernel crashes inside QEMU/KVM are observed:

  kernel BUG at kernel/time/timer.c:1154!
  BUG_ON(timer_pending(timer) || !timer->function) in add_timer_on().

At the same time another cpu got:

  general protection fault: 0000 [#1] SMP PTI of poinson pointer 0xdead000000000200 in:

  __hlist_del at include/linux/list.h:681
  (inlined by) detach_timer at kernel/time/timer.c:818
  (inlined by) expire_timers at kernel/time/timer.c:1355
  (inlined by) __run_timers at kernel/time/timer.c:1686
  (inlined by) run_timer_softirq at kernel/time/timer.c:1699

Unfortunately kernel logs are badly scrambled, stacktraces are lost.

Printing the timer->function before the BUG_ON() pointed to
clocksource_watchdog().

The execution of clocksource_watchdog() can race with a sequence of
clocksource_stop_watchdog() .. clocksource_start_watchdog():

expire_timers()
 detach_timer(timer, true);
  timer->entry.pprev = NULL;
 raw_spin_unlock_irq(&base->lock);
 call_timer_fn
  clocksource_watchdog()

					clocksource_watchdog_kthread() or
					clocksource_unbind()

					spin_lock_irqsave(&watchdog_lock, flags);
					clocksource_stop_watchdog();
					 del_timer(&watchdog_timer);
					 watchdog_running = 0;
					spin_unlock_irqrestore(&watchdog_lock, flags);

					spin_lock_irqsave(&watchdog_lock, flags);
					clocksource_start_watchdog();
					 add_timer_on(&watchdog_timer, ...);
					 watchdog_running = 1;
					spin_unlock_irqrestore(&watchdog_lock, flags);

  spin_lock(&watchdog_lock);
  add_timer_on(&watchdog_timer, ...);
   BUG_ON(timer_pending(timer) || !timer->function);
    timer_pending() -> true
    BUG()

I.e. inside clocksource_watchdog() watchdog_timer could be already armed.

Check timer_pending() before calling add_timer_on(). This is sufficient as
all operations are synchronized by watchdog_lock.

Fixes: 75c5158f70 ("timekeeping: Update clocksource with stop_machine")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/158048693917.4378.13823603769948933793.stgit@buzz
2020-02-01 11:07:56 +01:00
Mathieu Malaterre
0f48b41f59 clocksource: Move inline keyword to the beginning of function declarations
The inline keyword was not at the beginning of the function declarations.
Fix the following warnings triggered when using W=1:

  kernel/time/clocksource.c:108:1: warning: 'inline' is not at beginning of declaration [-Wold-style-declaration]
  kernel/time/clocksource.c:113:1: warning: 'inline' is not at beginning of declaration [-Wold-style-declaration]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: trivial@kernel.org
Cc: kernel-janitors@vger.kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20190524103339.28787-1-malat@debian.org
2019-06-14 17:04:03 +02:00
Thomas Gleixner
6c7811c628 time: Remove license boilerplate
The SPDX identifier defines the license of the files already. No need for
the boilerplates.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: David Riley <davidriley@chromium.org>
Cc: Colin Cross <ccross@android.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/r/20181031182253.132458951@linutronix.de
2018-11-23 11:51:21 +01:00
Thomas Gleixner
35728b8209 time: Add SPDX license identifiers
Update the time(r) core files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of the
full boiler plate text.

This work is based on a script and data from Philippe Ombredanne, Kate
Stewart and myself. The data has been created with two independent license
scanners and manual inspection.

The following files do not contain any direct license information and have
been omitted from the big initial SPDX changes:

  timeconst.bc: The .bc files were not touched
  time.c, timer.c, timekeeping.c: Licence was deduced from EXPORT_SYMBOL_GPL

As those files do not contain direct license references they fall under the
project license, i.e. GPL V2 only.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: David Riley <davidriley@chromium.org>
Cc: Colin Cross <ccross@android.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/r/20181031182252.879109557@linutronix.de
2018-11-23 11:51:20 +01:00
Thomas Gleixner
58c5fc2b96 time: Remove useless filenames in top level comments
Remove the pointless filenames in the top level comments. They have no
value at all and just occupy space. While at it tidy up some of the
comments and remove a stale one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Riley <davidriley@chromium.org>
Cc: Colin Cross <ccross@android.com>
Cc: Mark Brown <broonie@kernel.org>
Link: https://lkml.kernel.org/r/20181031182252.794898238@linutronix.de
2018-11-23 11:51:20 +01:00
Thomas Gleixner
d67f34c19a clocksource: Provide clocksource_arch_init()
Architectures have extra archdata in the clocksource, e.g. for VDSO
support. There are no sanity checks or general initializations for this
available. Add support for that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130706.973042587@linutronix.de
2018-10-04 23:00:24 +02:00
Peter Zijlstra
e2c631ba75 clocksource: Revert "Remove kthread"
I turns out that the silly spawn kthread from worker was actually needed.

clocksource_watchdog_kthread() cannot be called directly from
clocksource_watchdog_work(), because clocksource_select() calls
timekeeping_notify() which uses stop_machine(). One cannot use
stop_machine() from a workqueue() due lock inversions wrt CPU hotplug.

Revert the patch but add a comment that explain why we jump through such
apparently silly hoops.

Fixes: 7197e77abc ("clocksource: Remove kthread")
Reported-by: Siegfried Metz <frame@mailbox.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Tested-by: Kevin Shanahan <kevin@shanahan.id.au>
Tested-by: viktor_jaegerskuepper@freenet.de
Tested-by: Siegfried Metz <frame@mailbox.org>
Cc: rafael.j.wysocki@intel.com
Cc: len.brown@intel.com
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: bjorn.andersson@linaro.org
Link: https://lkml.kernel.org/r/20180905084158.GR24124@hirez.programming.kicks-ass.net
2018-09-06 23:38:35 +02:00
Baolin Wang
39232ed5a1 time: Introduce one suspend clocksource to compensate the suspend time
On some hardware with multiple clocksources, we have coarse grained
clocksources that support the CLOCK_SOURCE_SUSPEND_NONSTOP flag, but
which are less than ideal for timekeeping whereas other clocksources
can be better candidates but halt on suspend.

Currently, the timekeeping core only supports timing suspend using
CLOCK_SOURCE_SUSPEND_NONSTOP clocksources if that clocksource is the
current clocksource for timekeeping.

As a result, some architectures try to implement read_persistent_clock64()
using those non-stop clocksources, but isn't really ideal, which will
introduce more duplicate code. To fix this, provide logic to allow a
registered SUSPEND_NONSTOP clocksource, which isn't the current
clocksource, to be used to calculate the suspend time.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
[jstultz: minor tweaks to merge with previous resume changes]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2018-07-19 17:08:52 -07:00
Mathieu Malaterre
db6f9e55c8 clocksource: Move inline keyword to the beginning of function declarations
The inline keyword was not at the beginning of the function declarations.
Fix the following warnings triggered when using W=1:

  kernel/time/clocksource.c:456:1: warning: ‘inline’ is not at beginning of declaration [-Wold-style-declaration]
  kernel/time/clocksource.c:457:1: warning: ‘inline’ is not at beginning of declaration [-Wold-style-declaration]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: https://lkml.kernel.org/r/20180516195943.31924-1-malat@debian.org
2018-05-16 22:21:32 +02:00
Peter Zijlstra
7197e77abc clocksource: Remove kthread
The clocksource watchdog uses a work to spawn a kthread to run the
watchdog. That is about as silly as it sounds, run the watchdog
directly from the work.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Link: https://lkml.kernel.org/r/20180430100344.713862818@infradead.org
2018-05-02 16:11:46 +02:00
Peter Zijlstra
7dba33c634 clocksource: Rework stale comment
AFAICS the hotplug code no longer uses this function.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Link: https://lkml.kernel.org/r/20180430100344.656525644@infradead.org
2018-05-02 16:10:41 +02:00
Peter Zijlstra
cd2af07d82 clocksource: Consistent de-rate when marking unstable
When a registered clocksource gets marked unstable the watchdog_kthread
will de-rate and re-select the clocksource. Ensure it also de-rates
when getting called on an unregistered clocksource.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180430100344.594904898@infradead.org
2018-05-02 16:10:41 +02:00
Peter Zijlstra
5b9e886a4a clocksource: Initialize cs->wd_list
A number of places relies on list_empty(&cs->wd_list), however the
list_head does not get initialized. Do so upon registration, such that
thereafter it is possible to rely on list_empty() correctly reflecting
the list membership status.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Diego Viola <diego.viola@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: rui.zhang@intel.com
Link: https://lkml.kernel.org/r/20180430100344.472662715@infradead.org
2018-05-02 16:10:40 +02:00
Peter Zijlstra
2aae7bcfa4 clocksource: Allow clocksource_mark_unstable() on unregistered clocksources
Because of how the code flips between tsc-early and tsc clocksources
it might need to mark one or both unstable. The current code in
mark_tsc_unstable() only worked because previously it registered the
tsc clocksource once and then never touched it.

Since it now unregisters the tsc-early clocksource, it needs to know
if a clocksource got unregistered and the current cs->mult test
doesn't work for that. Instead use list_empty(&cs->list) to test for
registration.

Furthermore, since clocksource_mark_unstable() needs to place the cs
on the wd_list, it links the cs->list and cs->wd_list serialization.
It must not see a clocsource registered (!empty cs->list) but already
past dequeue_watchdog(). So place {en,de}queue{,_watchdog}() under the
same lock.

Provided cs->list is initialized to empty, this then allows us to
unconditionally use clocksource_mark_unstable(), regardless of the
registration state.

Fixes: aa83c45762 ("x86/tsc: Introduce early tsc clocksource")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Diego Viola <diego.viola@gmail.com>
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180502135312.GS12217@hirez.programming.kicks-ass.net
2018-05-02 16:10:40 +02:00
Baolin Wang
27263e8dc0 clocksource: Use ATTRIBUTE_GROUPS
Use ATTRIBUTE_GROUPS instead of manually creating the individual device
files.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: sboyd@codeaurora.org
Cc: broonie@kernel.org
Cc: john.stultz@linaro.org
Link: https://lkml.kernel.org/r/d80dccb981dc2461781ebb8d71a32ccdc1b0e6f9.1516167691.git.baolin.wang@linaro.org
2018-02-28 14:05:07 +01:00
Baolin Wang
e87821d18c clocksource: Use DEVICE_ATTR_RW/RO/WO to define device attributes
Convert DEVICE_ATTR to DEVICE_ATTR_RW/RO/WO which is the preferred and
simpler way of implementation.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: sboyd@codeaurora.org
Cc: broonie@kernel.org
Cc: john.stultz@linaro.org
Link: https://lkml.kernel.org/r/8f35c77e753e957b61187e8e7b2e4a3d61e4a72b.1516167691.git.baolin.wang@linaro.org
2018-02-28 14:04:52 +01:00
Baolin Wang
7f852afe44 clocksource: Don't walk the clocksource list for empty override
If the override clocksource name is empty there is no point in walking the
clocksource list for a match.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: sboyd@codeaurora.org
Cc: broonie@kernel.org
Cc: john.stultz@linaro.org
Link: https://lkml.kernel.org/r/069ce2a605546bcad6552968cff755f0a03f9f10.1516167691.git.baolin.wang@linaro.org
2018-02-28 14:04:52 +01:00
Kees Cook
e99e88a9d2 treewide: setup_timer() -> timer_setup()
This converts all remaining cases of the old setup_timer() API into using
timer_setup(), where the callback argument is the structure already
holding the struct timer_list. These should have no behavioral changes,
since they just change which pointer is passed into the callback with
the same available pointers after conversion. It handles the following
examples, in addition to some other variations.

Casting from unsigned long:

    void my_callback(unsigned long data)
    {
        struct something *ptr = (struct something *)data;
    ...
    }
    ...
    setup_timer(&ptr->my_timer, my_callback, ptr);

and forced object casts:

    void my_callback(struct something *ptr)
    {
    ...
    }
    ...
    setup_timer(&ptr->my_timer, my_callback, (unsigned long)ptr);

become:

    void my_callback(struct timer_list *t)
    {
        struct something *ptr = from_timer(ptr, t, my_timer);
    ...
    }
    ...
    timer_setup(&ptr->my_timer, my_callback, 0);

Direct function assignments:

    void my_callback(unsigned long data)
    {
        struct something *ptr = (struct something *)data;
    ...
    }
    ...
    ptr->my_timer.function = my_callback;

have a temporary cast added, along with converting the args:

    void my_callback(struct timer_list *t)
    {
        struct something *ptr = from_timer(ptr, t, my_timer);
    ...
    }
    ...
    ptr->my_timer.function = (TIMER_FUNC_TYPE)my_callback;

And finally, callbacks without a data assignment:

    void my_callback(unsigned long data)
    {
    ...
    }
    ...
    setup_timer(&ptr->my_timer, my_callback, 0);

have their argument renamed to verify they're unused during conversion:

    void my_callback(struct timer_list *unused)
    {
    ...
    }
    ...
    timer_setup(&ptr->my_timer, my_callback, 0);

The conversion is done with the following Coccinelle script:

spatch --very-quiet --all-includes --include-headers \
	-I ./arch/x86/include -I ./arch/x86/include/generated \
	-I ./include -I ./arch/x86/include/uapi \
	-I ./arch/x86/include/generated/uapi -I ./include/uapi \
	-I ./include/generated/uapi --include ./include/linux/kconfig.h \
	--dir . \
	--cocci-file ~/src/data/timer_setup.cocci

@fix_address_of@
expression e;
@@

 setup_timer(
-&(e)
+&e
 , ...)

// Update any raw setup_timer() usages that have a NULL callback, but
// would otherwise match change_timer_function_usage, since the latter
// will update all function assignments done in the face of a NULL
// function initialization in setup_timer().
@change_timer_function_usage_NULL@
expression _E;
identifier _timer;
type _cast_data;
@@

(
-setup_timer(&_E->_timer, NULL, _E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E->_timer, NULL, (_cast_data)_E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, &_E);
+timer_setup(&_E._timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, (_cast_data)&_E);
+timer_setup(&_E._timer, NULL, 0);
)

@change_timer_function_usage@
expression _E;
identifier _timer;
struct timer_list _stl;
identifier _callback;
type _cast_func, _cast_data;
@@

(
-setup_timer(&_E->_timer, _callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
 _E->_timer@_stl.function = _callback;
|
 _E->_timer@_stl.function = &_callback;
|
 _E->_timer@_stl.function = (_cast_func)_callback;
|
 _E->_timer@_stl.function = (_cast_func)&_callback;
|
 _E._timer@_stl.function = _callback;
|
 _E._timer@_stl.function = &_callback;
|
 _E._timer@_stl.function = (_cast_func)_callback;
|
 _E._timer@_stl.function = (_cast_func)&_callback;
)

// callback(unsigned long arg)
@change_callback_handle_cast
 depends on change_timer_function_usage@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
identifier _handle;
@@

 void _callback(
-_origtype _origarg
+struct timer_list *t
 )
 {
(
	... when != _origarg
	_handletype *_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
|
	... when != _origarg
	_handletype *_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
|
	... when != _origarg
	_handletype *_handle;
	... when != _handle
	_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
|
	... when != _origarg
	_handletype *_handle;
	... when != _handle
	_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
)
 }

// callback(unsigned long arg) without existing variable
@change_callback_handle_cast_no_arg
 depends on change_timer_function_usage &&
                     !change_callback_handle_cast@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
@@

 void _callback(
-_origtype _origarg
+struct timer_list *t
 )
 {
+	_handletype *_origarg = from_timer(_origarg, t, _timer);
+
	... when != _origarg
-	(_handletype *)_origarg
+	_origarg
	... when != _origarg
 }

// Avoid already converted callbacks.
@match_callback_converted
 depends on change_timer_function_usage &&
            !change_callback_handle_cast &&
	    !change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier t;
@@

 void _callback(struct timer_list *t)
 { ... }

// callback(struct something *handle)
@change_callback_handle_arg
 depends on change_timer_function_usage &&
	    !match_callback_converted &&
            !change_callback_handle_cast &&
            !change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
@@

 void _callback(
-_handletype *_handle
+struct timer_list *t
 )
 {
+	_handletype *_handle = from_timer(_handle, t, _timer);
	...
 }

// If change_callback_handle_arg ran on an empty function, remove
// the added handler.
@unchange_callback_handle_arg
 depends on change_timer_function_usage &&
	    change_callback_handle_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
identifier t;
@@

 void _callback(struct timer_list *t)
 {
-	_handletype *_handle = from_timer(_handle, t, _timer);
 }

// We only want to refactor the setup_timer() data argument if we've found
// the matching callback. This undoes changes in change_timer_function_usage.
@unchange_timer_function_usage
 depends on change_timer_function_usage &&
            !change_callback_handle_cast &&
            !change_callback_handle_cast_no_arg &&
	    !change_callback_handle_arg@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type change_timer_function_usage._cast_data;
@@

(
-timer_setup(&_E->_timer, _callback, 0);
+setup_timer(&_E->_timer, _callback, (_cast_data)_E);
|
-timer_setup(&_E._timer, _callback, 0);
+setup_timer(&_E._timer, _callback, (_cast_data)&_E);
)

// If we fixed a callback from a .function assignment, fix the
// assignment cast now.
@change_timer_function_assignment
 depends on change_timer_function_usage &&
            (change_callback_handle_cast ||
             change_callback_handle_cast_no_arg ||
             change_callback_handle_arg)@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_func;
typedef TIMER_FUNC_TYPE;
@@

(
 _E->_timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E->_timer.function =
-&_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E->_timer.function =
-(_cast_func)_callback;
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E->_timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-&_callback;
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-(_cast_func)_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
 ;
)

// Sometimes timer functions are called directly. Replace matched args.
@change_timer_function_calls
 depends on change_timer_function_usage &&
            (change_callback_handle_cast ||
             change_callback_handle_cast_no_arg ||
             change_callback_handle_arg)@
expression _E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_data;
@@

 _callback(
(
-(_cast_data)_E
+&_E->_timer
|
-(_cast_data)&_E
+&_E._timer
|
-_E
+&_E->_timer
)
 )

// If a timer has been configured without a data argument, it can be
// converted without regard to the callback argument, since it is unused.
@match_timer_function_unused_data@
expression _E;
identifier _timer;
identifier _callback;
@@

(
-setup_timer(&_E->_timer, _callback, 0);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0L);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0UL);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0L);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0UL);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0L);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0UL);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0L);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0UL);
+timer_setup(_timer, _callback, 0);
)

@change_callback_unused_data
 depends on match_timer_function_unused_data@
identifier match_timer_function_unused_data._callback;
type _origtype;
identifier _origarg;
@@

 void _callback(
-_origtype _origarg
+struct timer_list *unused
 )
 {
	... when != _origarg
 }

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-11-21 15:57:07 -08:00
Kees Cook
b9eaf18722 treewide: init_timer() -> setup_timer()
This mechanically converts all remaining cases of ancient open-coded timer
setup with the old setup_timer() API, which is the first step in timer
conversions. This has no behavioral changes, since it ultimately just
changes the order of assignment to fields of struct timer_list when
finding variations of:

    init_timer(&t);
    f.function = timer_callback;
    t.data = timer_callback_arg;

to be converted into:

    setup_timer(&t, timer_callback, timer_callback_arg);

The conversion is done with the following Coccinelle script, which
is an improved version of scripts/cocci/api/setup_timer.cocci, in the
following ways:
 - assignments-before-init_timer() cases
 - limit the .data case removal to the specific struct timer_list instance
 - handling calls by dereference (timer->field vs timer.field)

spatch --very-quiet --all-includes --include-headers \
	-I ./arch/x86/include -I ./arch/x86/include/generated \
	-I ./include -I ./arch/x86/include/uapi \
	-I ./arch/x86/include/generated/uapi -I ./include/uapi \
	-I ./include/generated/uapi --include ./include/linux/kconfig.h \
	--dir . \
	--cocci-file ~/src/data/setup_timer.cocci

@fix_address_of@
expression e;
@@

 init_timer(
-&(e)
+&e
 , ...)

// Match the common cases first to avoid Coccinelle parsing loops with
// "... when" clauses.

@match_immediate_function_data_after_init_timer@
expression e, func, da;
@@

-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );
(
-\(e.function\|e->function\) = func;
-\(e.data\|e->data\) = da;
|
-\(e.data\|e->data\) = da;
-\(e.function\|e->function\) = func;
)

@match_immediate_function_data_before_init_timer@
expression e, func, da;
@@

(
-\(e.function\|e->function\) = func;
-\(e.data\|e->data\) = da;
|
-\(e.data\|e->data\) = da;
-\(e.function\|e->function\) = func;
)
-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );

@match_function_and_data_after_init_timer@
expression e, e2, e3, e4, e5, func, da;
@@

-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );
 ... when != func = e2
     when != da = e3
(
-e.function = func;
... when != da = e4
-e.data = da;
|
-e->function = func;
... when != da = e4
-e->data = da;
|
-e.data = da;
... when != func = e5
-e.function = func;
|
-e->data = da;
... when != func = e5
-e->function = func;
)

@match_function_and_data_before_init_timer@
expression e, e2, e3, e4, e5, func, da;
@@
(
-e.function = func;
... when != da = e4
-e.data = da;
|
-e->function = func;
... when != da = e4
-e->data = da;
|
-e.data = da;
... when != func = e5
-e.function = func;
|
-e->data = da;
... when != func = e5
-e->function = func;
)
... when != func = e2
    when != da = e3
-init_timer
+setup_timer
 ( \(&e\|e\)
+, func, da
 );

@r1 exists@
expression t;
identifier f;
position p;
@@

f(...) { ... when any
  init_timer@p(\(&t\|t\))
  ... when any
}

@r2 exists@
expression r1.t;
identifier g != r1.f;
expression e8;
@@

g(...) { ... when any
  \(t.data\|t->data\) = e8
  ... when any
}

// It is dangerous to use setup_timer if data field is initialized
// in another function.
@script:python depends on r2@
p << r1.p;
@@

cocci.include_match(False)

@r3@
expression r1.t, func, e7;
position r1.p;
@@

(
-init_timer@p(&t);
+setup_timer(&t, func, 0UL);
... when != func = e7
-t.function = func;
|
-t.function = func;
... when != func = e7
-init_timer@p(&t);
+setup_timer(&t, func, 0UL);
|
-init_timer@p(t);
+setup_timer(t, func, 0UL);
... when != func = e7
-t->function = func;
|
-t->function = func;
... when != func = e7
-init_timer@p(t);
+setup_timer(t, func, 0UL);
)

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-11-21 15:57:06 -08:00
Peter Zijlstra
b421b22b00 x86/tsc, sched/clock, clocksource: Use clocksource watchdog to provide stable sync points
Currently we keep sched_clock_tick() active for stable TSC in order to
keep the per-CPU state semi up-to-date. The (obvious) problem is that
by the time we detect TSC is borked, our per-CPU state is also borked.

So hook into the clocksource watchdog and call a method after we've
found it to still be stable.

There's the obvious race where the TSC goes wonky between finding it
stable and us running the callback, but closing that is too much work
and not really worth it, since we're already detecting TSC wobbles
after the fact, so we cannot, per definition, fully avoid funny clock
values.

And since the watchdog runs less often than the tick, this is also an
optimization.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: 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>
2017-05-15 10:15:18 +02:00
Thomas Gleixner
12907fbb1a sched/clock, clocksource: Add optional cs::mark_unstable() method
PeterZ reported that we'd fail to mark the TSC unstable when the
clocksource watchdog finds it unsuitable.

Allow a clocksource to run a custom action when its being marked
unstable and hook up the TSC unstable code.

Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 11:29:43 +01:00
Thomas Gleixner
a5a1d1c291 clocksource: Use a plain u64 instead of cycle_t
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>
2016-12-25 11:04:12 +01:00
Murali Karicheri
5304121ada clocksource: export the clocks_calc_mult_shift to use by timestamp code
The CPSW CPTS driver is capable of doing timestamping on tx/rx packets and
requires to know mult and shift factors for timestamp conversion from raw
value to nanoseconds (ptp clock). Now these mult and shift factors are
calculated manually and provided through DT, which makes very hard to
support of a lot number of platforms, especially if CPTS refclk is not the
same for some kind of boards and depends on efuse settings (Keystone 2
platforms). Hence, export clocks_calc_mult_shift() to allow drivers like
CPSW CPTS (and other ptp drivesr) to benefit from automaitc calculation of
mult and shift factors.

Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-07 11:13:48 -05:00
Kyle Walker
36374583f9 clocksource: Defer override invalidation unless clock is unstable
Clocksources don't get the VALID_FOR_HRES flag until they have been
checked by a watchdog. However, when using an override, the
clocksource_select logic will clear the override value if the
clocksource is not marked VALID_FOR_HRES during that inititial check.
When using the boot arguments clocksource=<foo>, this selection can
run before the watchdog, and can cause the override to be incorrectly
cleared.

To address this condition, the override_name is only invalidated for
unstable clocksources. Otherwise, the override is left intact until after
the watchdog has validated the clocksource as stable/unstable.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Kyle Walker <kwalker@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-08-31 14:43:33 -07:00
Minfei Huang
0fb71d340d clocksource: Make clocksource insert entry more efficient
In clocksource_enqueue(), it is unnecessary to continue looping
the list, if we find there is an entry that the value of rating
is smaller than the new one. It is safe to be out the loop,
because all of entry are inserted in descending order.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Minfei Huang <mnghuan@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-06-20 12:46:34 -07:00
Vitaly Kuznetsov
bbf66d897a clocksource: Allow unregistering the watchdog
Hyper-V vmbus module registers TSC page clocksource when loaded. This is
the clocksource with the highest rating and thus it becomes the watchdog
making unloading of the vmbus module impossible.
Separate clocksource_select_watchdog() from clocksource_enqueue_watchdog()
and use it on clocksource register/rating change/unregister.

After all, lobotomized monkeys may need some love too.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1453483913-25672-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-27 12:38:05 +01:00
Seiichi Ikarashi
390dd67c47 clocksource: Add CPU info to clocksource watchdog reporting
The clocksource watchdog reporting was improved by 0b046b217a.
I want to add the info of CPU where the watchdog detects a
deviation because it is necessary to identify the trouble spot
if the clocksource is TSC.

Signed-off-by: Seiichi Ikarashi <s.ikarashi@jp.fujitsu.com>
[jstultz: Tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-12-07 12:15:28 -08:00
Andrew Morton
79211c8ed1 remove abs64()
Switch everything to the new and more capable implementation of abs().
Mainly to give the new abs() a bit of a workout.

Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-09 15:11:24 -08:00
Ingo Molnar
b9f27c0f4f Linux 4.3-rc5
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Merge tag 'v4.3-rc5' into timers/core, to pick up fixes before applying new changes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-12 09:51:18 +02:00
Guillaume Gomez
cfed432d7f clocksource: Remove return statement from void functions
Signed-off-by: Guillaume Gomez <guillaume1.gomez@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/CAAOQCfSDgmqSWDBsetau%2ByF8x0%2BDagCF_pfFw0p5xH_BKkKEog@mail.gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-10-11 22:13:46 +02:00