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2017-11-21treewide: setup_timer() -> timer_setup()Kees Cook
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>
2017-11-21treewide: init_timer() -> setup_timer()Kees Cook
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>
2017-05-15x86/tsc, sched/clock, clocksource: Use clocksource watchdog to provide ↵Peter Zijlstra
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>
2017-01-14sched/clock, clocksource: Add optional cs::mark_unstable() methodThomas Gleixner
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>
2016-12-25clocksource: Use a plain u64 instead of cycle_tThomas Gleixner
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>
2016-12-07clocksource: export the clocks_calc_mult_shift to use by timestamp codeMurali Karicheri
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>
2016-08-31clocksource: Defer override invalidation unless clock is unstableKyle Walker
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>
2016-06-20clocksource: Make clocksource insert entry more efficientMinfei Huang
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>
2016-01-27clocksource: Allow unregistering the watchdogVitaly Kuznetsov
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>
2015-12-07clocksource: Add CPU info to clocksource watchdog reportingSeiichi Ikarashi
The clocksource watchdog reporting was improved by 0b046b217ad4c6. 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>
2015-11-09remove abs64()Andrew Morton
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>
2015-10-12Merge tag 'v4.3-rc5' into timers/core, to pick up fixes before applying new ↵Ingo Molnar
changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-11clocksource: Remove return statement from void functionsGuillaume Gomez
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>
2015-10-02clocksource: Fix abs() usage w/ 64bit valuesJohn Stultz
This patch fixes one cases where abs() was being used with 64-bit nanosecond values, where the result may be capped at 32-bits. This potentially could cause watchdog false negatives on 32-bit systems, so this patch addresses the issue by using abs64(). Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1442279124-7309-2-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-22time: Fix spelling in commentsZhen Lei
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tianhong Ding <dingtianhong@huawei.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Xinwei Hu <huxinwei@huawei.com> Cc: Xunlei Pang <pang.xunlei@linaro.org> Cc: Zefan Li <lizefan@huawei.com> Link: http://lkml.kernel.org/r/1440484973-13892-1-git-send-email-thunder.leizhen@huawei.com [ Fixed yet another typo in one of the sentences fixed. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-10clocksource: Use current logging styleJoe Perches
clocksource messages aren't prefixed in dmesg so it's a bit unclear what subsystem emits the messages. Use pr_fmt and pr_<level> to auto-prefix the messages appropriately. Miscellanea: o Remove "Warning" from KERN_WARNING level messages o Align "timekeeping watchdog: " messages o Coalesce formats o Align multiline arguments Signed-off-by: Joe Perches <joe@perches.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1432579795.2846.75.camel@perches.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-04-03clocksource: Improve comment explaining clocks_calc_max_nsecs()'s 50% safety ↵John Stultz
margin Ingo noted that the description of clocks_calc_max_nsecs()'s 50% safety margin was somewhat circular. So this patch tries to improve the comment to better explain what we mean by the 50% safety margin and why we need it. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1427945681-29972-20-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01tick: Move core only declarations and functions to coreThomas Gleixner
No point to expose everything to the world. People just believe such functions can be abused for whatever purposes. Sigh. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Rebased on top of 4.0-rc5 ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Nicolas Pitre <nico@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/28017337.VbCUc39Gme@vostro.rjw.lan [ Merged to latest timers/core ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01tick: Move clocksource related stuff to timekeeping.hThomas Gleixner
Move clocksource related stuff to timekeeping.h and remove the pointless include from ntp.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/2714218.nM5AEfAHj0@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-13clocksource: Rename __clocksource_updatefreq_*() to ↵John Stultz
__clocksource_update_freq_*() Ingo requested this function be renamed to improve readability, so I've renamed __clocksource_updatefreq_scale() as well as the __clocksource_updatefreq_hz/khz() functions to avoid squishedtogethernames. This touches some of the sh clocksources, which I've not tested. The arch/arm/plat-omap change is just a comment change for consistency. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-13-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-13clocksource: Add some debug info about clocksources being registeredJohn Stultz
Print the mask, max_cycles, and max_idle_ns values for clocksources being registered. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-12-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-13clocksource: Mostly kill clocksource_register()John Stultz
A long running project has been to clean up remaining uses of clocksource_register(), replacing it with the simpler clocksource_register_khz/hz() functions. However, there are a few cases where we need to self-define our mult/shift values, so switch the function to a more obviously internal __clocksource_register() name, and consolidate much of the internal logic so we don't have duplication. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-10-git-send-email-john.stultz@linaro.org [ Minor cleanups. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-13clocksource: Improve clocksource watchdog reportingJohn Stultz
The clocksource watchdog reporting has been less helpful then desired, as it just printed the delta between the two clocksources. This prevents any useful analysis of why the skew occurred. Thus this patch tries to improve the output when we mark a clocksource as unstable, printing out the cycle last and now values for both the current clocksource and the watchdog clocksource. This will allow us to see if the result was due to a false positive caused by a problematic watchdog. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-9-git-send-email-john.stultz@linaro.org [ Minor cleanups of kernel messages. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-12clocksource: Add 'max_cycles' to 'struct clocksource'John Stultz
In order to facilitate clocksource validation, add a 'max_cycles' field to the clocksource structure which will hold the maximum cycle value that can safely be multiplied without potentially causing an overflow. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-4-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-12clocksource: Simplify the logic around clocksource wrapping safety marginsJohn Stultz
The clocksource logic has a number of places where we try to include a safety margin. Most of these are 12% safety margins, but they are inconsistently applied and sometimes are applied on top of each other. Additionally, in the previous patch, we corrected an issue where we unintentionally in effect created a 50% safety margin, which these 12.5% margins where then added to. So to simplify the logic here, this patch removes the various 12.5% margins, and consolidates adding the margin in one place: clocks_calc_max_nsecs(). Additionally, Linus prefers a 50% safety margin, as it allows bad clock values to be more easily caught. This should really have no net effect, due to the corrected issue earlier which caused greater then 50% margins to be used w/o issue. Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Stephen Boyd <sboyd@codeaurora.org> (for the sched_clock.c bit) Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-12clocksource: Simplify the clocks_calc_max_nsecs() logicJohn Stultz
The previous clocks_calc_max_nsecs() code had some unecessarily complex bit logic to find the max interval that could cause multiplication overflows. Since this is not in the hot path, just do the divide to make it easier to read. The previous implementation also had a subtle issue that it avoided overflows with signed 64-bit values, where as the intervals are always unsigned. This resulted in overly conservative intervals, which other safety margins were then added to, reducing the intended interval length. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1426133800-29329-2-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-12-30time: move the timecounter/cyclecounter code into its own file.Richard Cochran
The timecounter code has almost nothing to do with the clocksource code. Let it live in its own file. This will help isolate the timecounter users from the clocksource users in the source tree. Signed-off-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-29clocksource: Fix 'clcoksource' typo in commentJames Hartley
Simple typo in a comment, so fix it. Signed-off-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-07-23clocksource: Make delta calculation a functionThomas Gleixner
We want to move the TSC sanity check into core code to make NMI safe accessors to clock monotonic[_raw] possible. For this we need to sanity check the delta calculation. Create a helper function and convert all sites to use it. [ Build fix from jstultz ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-10-18time: Fix signedness bug in sysfs_get_uname() and its callersPatrick Palka
sysfs_get_uname() is erroneously declared as returning size_t even though it may return a negative value, specifically -EINVAL. Its callers then check whether its return value is less than zero and indeed that is never the case for size_t. This patch changes sysfs_get_uname() to return ssize_t and makes sure its callers use ssize_t accordingly. Signed-off-by: Patrick Palka <patrick@parcs.ath.cx> [jstultz: Didn't apply cleanly, as a similar partial fix was also applied so had to resolve the collisions] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-09-17clocksource: Fix 'ret' data type of sysfs_override_clocksource() and ↵Elad Wexler
sysfs_unbind_clocksource() sysfs_override_clocksource(): The expression 'if (ret >= 0)' is always true. This will cause clocksource_select() to always run. Thus modified ret to be of type ssize_t. sysfs_unbind_clocksource(): The expression 'if (ret < 0)' is always false. So in case sysfs_get_uname() failed, the expression won't take an effect. Thus modified ret to be of type ssize_t. Signed-off-by: Elad Wexler <elad.wexler@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-09-16Merge branch 'fortglx/3.12/time' into fortglx/3.13/timeJohn Stultz
Merge in the timekeeping changes that missed 3.12 Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-07-30clocksource: Extract max nsec calculation into separate functionStephen Boyd
We need to calculate the same number in the clocksource code and the sched_clock code, so extract this code into its own function. We also drop the min_t and just use min() because the two types are the same. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-07-22clocksource: Fix !CONFIG_CLOCKSOURCE_WATCHDOG compilePrarit Bhargava
If I explicitly disable the clocksource watchdog in the x86 Kconfig, the x86 kernel will not compile unless this is properly defined. Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Signed-off-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-07-05clocksource: Reselect clocksource when watchdog validated high-res capabilityThomas Gleixner
Up to commit 5d33b883a (clocksource: Always verify highres capability) we had no sanity check when selecting a clocksource, which prevented that a non highres capable clocksource is used when the system already switched to highres/nohz mode. The new sanity check works as Alex and Tim found out. It prevents the TSC from being used. This happens because on x86 the boot process looks like this: tsc_start_freqency_validation(TSC); clocksource_register(HPET); clocksource_done_booting(); clocksource_select() Selects HPET which is valid for high-res switch_to_highres(); clocksource_register(TSC); TSC is not selected, because it is not yet flagged as VALID_HIGH_RES clocksource_watchdog() Validates TSC for highres, but that does not make TSC the current clocksource. Before the sanity check was added, we installed TSC unvalidated which worked most of the time. If the TSC was really detected as unstable, then the unstable logic removed it and installed HPET again. The sanity check is correct and needed. So the watchdog needs to kick a reselection of the clocksource, when it qualifies TSC as a valid high res clocksource. To solve this, we mark the clocksource which got the flag CLOCK_SOURCE_VALID_FOR_HRES set by the watchdog with an new flag CLOCK_SOURCE_RESELECT and trigger the watchdog thread. The watchdog thread evaluates the flag and invokes clocksource_select() when set. To avoid that the clocksource_done_booting() code, which is about to install the first real clocksource anyway, needs to go through clocksource_select and tick_oneshot_notify() pointlessly, split out the clocksource_watchdog_kthread() list walk code and invoke the select/notify only when called from clocksource_watchdog_kthread(). So clocksource_done_booting() can utilize the same splitout code without the select/notify invocation and the clocksource_mutex unlock/relock dance. Reported-and-tested-by: Alex Shi <alex.shi@intel.com> Cc: Hans Peter Anvin <hpa@linux.intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <andi.kleen@intel.com> Tested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@kernel.org> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1307042239150.11637@ionos.tec.linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-28clocksource: Implement clocksource_select_fallback() for ↵Thomas Gleixner
CONFIG_ARCH_USES_GETTIMEOFFSET=y commit 7eaeb34305 (clocksource: Provide unbind interface in sysfs) implemented clocksource_select_fallback() which is not defined for CONFIG_ARCH_USES_GETTIMEOFFSET=y. Add an empty inline function for that. Reported-by: Ingo Molnar <mingo@kernel.org> Reported-by: fengguang.wu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clockevents: Implement unbind functionalityThomas Gleixner
Provide a sysfs interface to allow unbinding of clockevent devices. The device is unbound if it is unused or if there is a replacement device available. Unbinding of broadcast devices is not supported as we don't want to foster that nonsense. If no replacement device is available the unbind returns -EBUSY. Unbind is available from the kernel and through sysfs, which is necessary to drop the module refcount. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.499216659@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clocksource: Let clocksource_unregister() return success/errorThomas Gleixner
The unregister call can fail, if the clocksource is the current one and there is no replacement clocksource available. It can also fail, if the clocksource is the watchdog clocksource and I'm not going to provide support for this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.029915527@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clocksource: Provide unbind interface in sysfsThomas Gleixner
With the module refcount held for the current clocksource there is no way to unload the module. Provide a sysfs interface which allows to unbind the clocksource. One could argue that the clocksource override could be (ab)used to do so, but the clocksource override cannot be used from the kernel itself, while an unbind function can be used to programmatically check whether a clocksource can be shutdown or not. The unbind functionality uses the new skip current feature of clocksource_select and verifies that a fallback clocksource has been installed. If the clocksource which should be unbound is the current clocksource and no fallback can be found, unbind returns -EBUSY. This does not support the unbinding of a clocksource which is used as the watchdog clocksource. No point in fostering crappy hardware. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143435.964218245@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clocksource: Split out user string inputThomas Gleixner
Split out the user string input for clocksource override. Preparatory patch for unbind. [ jstultz: Fix an off by one error ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143435.895851338@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clocksource: Allow clocksource select to skip current clocksourceThomas Gleixner
Preparatory patch for clocksource unbind support. Split out code from clocksource_select and modify it, so it skips the current clocksource on request and tries to find a fallback clocksource. Convert all existing users. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143435.834965397@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clocksource: Let timekeeping_notify return success/errorThomas Gleixner
timekeeping_notify() can fail due cs->enable() failure. Though the caller does not notice and happily keeps the wrong clocksource as the current one. Let the caller know about failure, so the current clocksource will be shown correctly in sysfs. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143435.696321912@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clocksource: Always verify highres capabilityThomas Gleixner
If a clocksource has a (wrong) high rating, but can't be used as a timebase for oneshot tick mode, it is unconditionally selected even when the system is already in oneshot tick mode. This causes full system failure. Verify the clocksource selection against the oneshot mode. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143435.635040849@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-23kernel-time: fix s/then/than/ spelling errorsJim Cromie
Use than for comparisons, like more than. CC: John Stultz <john.stultz@linaro.org> Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-01-06Merge branch 'driver-core-next' into Linux 3.2Greg Kroah-Hartman
This resolves the conflict in the arch/arm/mach-s3c64xx/s3c6400.c file, and it fixes the build error in the arch/x86/kernel/microcode_core.c file, that the merge did not catch. The microcode_core.c patch was provided by Stephen Rothwell <sfr@canb.auug.org.au> who was invaluable in the merge issues involved with the large sysdev removal process in the driver-core tree. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-19time/clocksource: Fix kernel-doc warningsKusanagi Kouichi
Fix various KernelDoc build warnings. Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp> Cc: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/20111219091320.0D5AF6FC03D@msa105.auone-net.jp Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-14clocksource: convert sysdev_class to a regular subsystemKay Sievers
After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-01clocksource: Fix bug with max_deferment margin calculationYang Honggang (Joseph)
In order to leave a margin of 12.5% we should >> 3 not >> 5. CC: stable@kernel.org Signed-off-by: Yang Honggang (Joseph) <eagle.rtlinux@gmail.com> [jstultz: Modified commit subject] Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-11-10clocksource: Avoid selecting mult values that might overflow when adjustedJohn Stultz
For some frequencies, the clocks_calc_mult_shift() function will unfortunately select mult values very close to 0xffffffff. This has the potential to overflow when NTP adjusts the clock, adding to the mult value. This patch adds a clocksource.maxadj value, which provides an approximation of an 11% adjustment(NTP limits adjustments to 500ppm and the tick adjustment is limited to 10%), which could be made to the clocksource.mult value. This is then used to both check that the current mult value won't overflow/underflow, as well as warning us if the timekeeping_adjust() code pushes over that 11% boundary. v2: Fix max_adjustment calculation, and improve WARN_ONCE messages. v3: Don't warn before maxadj has actually been set CC: Yong Zhang <yong.zhang0@gmail.com> CC: David Daney <ddaney.cavm@gmail.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Chen Jie <chenj@lemote.com> CC: zhangfx <zhangfx@lemote.com> CC: stable@kernel.org Reported-by: Chen Jie <chenj@lemote.com> Reported-by: zhangfx <zhangfx@lemote.com> Tested-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-09-13clocksource: Make watchdog reset locklessThomas Gleixner
KGDB needs to trylock watchdog_lock when trying to reset the clocksource watchdog after the system has been stopped to avoid a potential deadlock. When the trylock fails TSC usually becomes unstable. We can be more clever by using an atomic counter and checking it in the clocksource_watchdog callback. We restart the watchdog whenever the counter is > 0 and only decrement the counter when we ran through a full update cycle. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@us.ibm.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1109121326280.2723@ionos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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