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* clocksource: Delay clocksource down rating to late bootThomas Gleixner2009-09-14
| | | | | | | | | | | | | | | The down rating of clock sources in the early boot process via the clock source watchdog mechanism can happen way before the per cpu event queues are initialized. This leads to a boot crash on x86 when the TSC is marked unstable in the SMP bring up. The selection of a clock source for time keeping happens in the late boot process so we can safely delay the list manipulation until clocksource_done_booting() is called. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
* clocksource: clocksource_select must be called with mutex lockedThomas Gleixner2009-09-14
| | | | | | | | | The callers of clocksource_select must hold clocksource_mutex to protect the clocksource_list. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
* clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crashMartin Schwidefsky2009-09-11
| | | | | | | | | | | | | | | | | The watchdog timer is started after the watchdog clocksource and at least one watched clocksource have been registered. The clocksource work element watchdog_work is initialized just before the clocksource timer is started. This is too late for the clocksource_mark_unstable call from native_cpu_up. To fix this use a static initializer for watchdog_work. This resolves a boot crash reported by multiple people. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20090911153305.3fe9a361@skybase> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* clocksource: Resolve cpu hotplug dead lock with TSC unstableThomas Gleixner2009-08-28
| | | | | | | | | | | | | | | | | | | | | Martin Schwidefsky analyzed it: To register a clocksource the clocksource_mutex is acquired and if necessary timekeeping_notify is called to install the clocksource as the timekeeper clock. timekeeping_notify uses stop_machine which needs to take cpu_add_remove_lock mutex. Starting a new cpu is done with the cpu_add_remove_lock mutex held. native_cpu_up checks the tsc of the new cpu and if the tsc is no good clocksource_change_rating is called. Which needs the clocksource_mutex and the deadlock is complete. The solution is to replace the TSC via the clocksource watchdog mechanism. Mark the TSC as unstable and schedule the watchdog work so it gets removed in the watchdog thread context. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com>
* clocksource: Avoid clocksource watchdog circular locking dependencyMartin Schwidefsky2009-08-19
| | | | | | | | | | | | | stop_machine from a multithreaded workqueue is not allowed because of a circular locking dependency between cpu_down and the workqueue execution. Use a kernel thread to do the clocksource downgrade. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: john stultz <johnstul@us.ibm.com> LKML-Reference: <20090818170942.3ab80c91@skybase> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Protect the watchdog rating changes with clocksource_mutexThomas Gleixner2009-08-19
| | | | | | | | | | | | | | | | | | | Martin pointed out that commit 6ea41d2529 (clocksource: Call clocksource_change_rating() outside of watchdog_lock) has a theoretical reference count problem. The calls to clocksource_change_rating() are now done outside of the clocksource mutex and outside of the watchdog lock. A concurrent clocksource_unregister() could remove the clock. Split out the code which changes the rating from clocksource_change_rating() into __clocksource_change_rating(). Protect the clocksource_watchdog_work() code sequence with the clocksource_mutex() and call __clocksource_change_rating(). LKML-Reference: <alpine.LFD.2.00.0908171038420.2782@localhost.localdomain> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
* clocksource: Call clocksource_change_rating() outside of watchdog_lockThomas Gleixner2009-08-15
| | | | | | | | The changes to the watchdog logic introduced a lock inversion between watchdog_lock and clocksource_mutex. Change the rating outside of watchdog_lock to avoid it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timekeeping: Update clocksource with stop_machineMartin Schwidefsky2009-08-15
| | | | | | | | | | | | | | update_wall_time calls change_clocksource HZ times per second to check if a new clock source is available. In close to 100% of all calls there is no new clock. Replace the tick based check by an update done with stop_machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134810.711836357@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* timekeeping: Introduce struct timekeeperMartin Schwidefsky2009-08-15
| | | | | | | | | | | | | | | | | | Add struct timekeeper to keep the internal values timekeeping.c needs in regard to the currently selected clock source. This moves the timekeeping intervals, xtime_nsec and the ntp error value from struct clocksource to struct timekeeper. The raw_time is removed from the clocksource as well. It gets treated like xtime as a global variable. Eventually xtime raw_time should be moved to struct timekeeper. [ tglx: minor cleanup ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.613209842@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Move watchdog downgrade to a work queue threadMartin Schwidefsky2009-08-15
| | | | | | | | | | | | | Move the downgrade of an unstable clocksource from the timer interrupt context into the process context of a work queue thread. This is needed to be able to do the clocksource switch with stop_machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.354926067@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Refactor clocksource watchdogMartin Schwidefsky2009-08-15
| | | | | | | | | | | | | Refactor clocksource watchdog code to make it more readable. Add clocksource_dequeue_watchdog to remove a clocksource from the watchdog list when it is unregistered. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.110881699@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Simplify clocksource watchdog resume logicMartin Schwidefsky2009-08-15
| | | | | | | | | | | | To resume the clocksource watchdog just remove the CLOCK_SOURCE_WATCHDOG bit from the watched clocksource. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.880925790@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Delay clocksource watchdog highres enablementMartin Schwidefsky2009-08-15
| | | | | | | | | | | | | | The clocksource watchdog marks a clock as highres capable before it checked the deviation from the watchdog clocksource even for a single time. Make sure that the deviation is at least checked once before doing the switch to highres mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.627795883@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Cleanup clocksource selectionMartin Schwidefsky2009-08-15
| | | | | | | | | | | | | | | | | | | | | | If a non high-resolution clocksource is first set as override clock and then registered it becomes active even if the system is in one-shot mode. Move the override check from sysfs_override_clocksource to the clocksource selection. That fixes the bug and simplifies the code. The check in clocksource_register for double registration of the same clocksource is removed without replacement. To find the initial clocksource a new weak function in jiffies.c is defined that returns the jiffies clocksource. The architecture code can then override the weak function with a more suitable clocksource, e.g. the TOD clock on s390. [ tglx: Folded in a fix from John Stultz ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.388024160@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Prevent NULL pointer dereferenceThomas Gleixner2009-07-19
| | | | | | | | | | Writing a zero length string to sys/.../current_clocksource will cause a NULL pointer dereference if the clock events system is in one shot (highres or nohz) mode. Pointed-out-by: Dan Carpenter <error27@gmail.com> LKML-Reference: <alpine.DEB.2.00.0907191545580.12306@bicker> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: prevent selection of low resolution clocksourse also for nohz=onThomas Gleixner2009-06-13
| | | | | | | | | | | | | | commit 3f68535adad (clocksource: sanity check sysfs clocksource changes) prevents selection of non high resolution capable clocksources when high resolution mode is active, but did not take into account that the same rules apply for highres=off nohz=on. Check the tick device mode instead of hrtimer_hres_active() to verify whether the system needs to be protected from a switch to jiffies or other non highres capable clock sources. Reported-by: Luming Yu <luming.yu@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: sanity check sysfs clocksource changesjohn stultz2009-06-11
| | | | | | | | | | | | | | | Thomas, Andrew and Ingo pointed out that we don't have any safety checks in the clocksource sysfs entries to make sure sysadmins don't try to change the clocksource to a non high-res timer capable clocksource (such as jiffies) when high-res timers (HRT) is enabled. Doing so will likely hang a system. Correct this by filtering non HRT clocksources from available_clocksources and not accepting non HRT clocksources with HRT enabled. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: setup mult_orig in clocksource_enable()Magnus Damm2009-05-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Setup clocksource mult_orig in clocksource_enable(). Clocksource drivers can save power by using keeping the device clock disabled while the clocksource is unused. In practice this means that the enable() and disable() callbacks perform clk_enable() and clk_disable(). The enable() callback may also use clk_get_rate() to get the clock rate from the clock framework. This information can then be used to calculate the shift and mult variables. Currently the mult_orig variable is setup from mult at registration time only. This is conflicting with the above case since the clock is disabled and the mult variable is not yet calculated at the time of registration. Moving the mult_orig setup code to clocksource_enable() allows us to both handle the common case with no enable() callback and the mult-changed-after-enable() case. [ Impact: allow dynamic clock source usage ] Signed-off-by: Magnus Damm <damm@igel.co.jp> LKML-Reference: <20090501054546.8193.10688.sendpatchset@rx1.opensource.se> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: pass clocksource to read() callbackMagnus Damm2009-04-21
| | | | | | | | | | | | | | Pass clocksource pointer to the read() callback for clocksources. This allows us to share the callback between multiple instances. [hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods] [akpm@linux-foundation.org: cleanup] Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* clocksource: allow usage independent of timekeeping.cPatrick Ohly2009-02-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | So far struct clocksource acted as the interface between time/timekeeping.c and hardware. This patch generalizes the concept so that a similar interface can also be used in other contexts. For that it introduces new structures and related functions *without* touching the existing struct clocksource. The reasons for adding these new structures to clocksource.[ch] are * the APIs are clearly related * struct clocksource could be cleaned up to use the new structs * avoids proliferation of files with similar names (timesource.h? timecounter.h?) As outlined in the discussion with John Stultz, this patch adds * struct cyclecounter: stateless API to hardware which counts clock cycles * struct timecounter: stateful utility code built on a cyclecounter which provides a nanosecond counter * only the function to read the nanosecond counter; deltas are used internally and not exposed to users of timecounter The code does no locking of the shared state. It must be called at least as often as the cycle counter wraps around to detect these wrap arounds. Both is the responsibility of the timecounter user. Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/Rusty Russell2008-12-31
| | | | | | | | | | Impact: cleanup Simple replacement, now the _nr is redundant. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Cc: Ingo Molnar <mingo@redhat.com>
* cpumask: convert kernel time functionsRusty Russell2008-12-31
| | | | | | | | | | | | | | | | Impact: Use new APIs Convert kernel/time functions to use struct cpumask *. Note the ugly bitmap declarations in tick-broadcast.c. These should be cpumask_var_t, but there was no obvious initialization function to put the alloc_cpumask_var() calls in. This was safe. (Eventually 'struct cpumask' will be undefined for CONFIG_CPUMASK_OFFSTACK, so we use a bitmap here to show we really mean it). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
* clocksource: keep track of original clocksource frequencyJohn Stultz2008-08-21
| | | | | | | | | | | | | | | | | | | | | | | | | | The clocksource frequency is represented by clocksource->mult/2^(clocksource->shift). Currently, when NTP makes adjustments to the clock frequency, they are made directly to the mult value. This has the drawback that once changed, we cannot know what the orignal mult value was, or how much adjustment has been applied. This property causes problems in calculating proper ntp intervals when switching back and forth between clocksources. This patch separates the current mult value into a mult and mult_orig pair. The mult_orig value stays constant, while the ntp clocksource adjustments are done only to the mult value. This allows for correct ntp interval calculation and additionally lays the groundwork for a new notion of time, what I'm calling the monotonic-raw time, which is introduced in a following patch. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'cpus4096-for-linus' of ↵Linus Torvalds2008-07-23
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'cpus4096-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits) NR_CPUS: Replace NR_CPUS in speedstep-centrino.c cpumask: Provide a generic set of CPUMASK_ALLOC macros, FIXUP NR_CPUS: Replace NR_CPUS in cpufreq userspace routines NR_CPUS: Replace per_cpu(..., smp_processor_id()) with __get_cpu_var NR_CPUS: Replace NR_CPUS in arch/x86/kernel/genapic_flat_64.c NR_CPUS: Replace NR_CPUS in arch/x86/kernel/genx2apic_uv_x.c NR_CPUS: Replace NR_CPUS in arch/x86/kernel/cpu/proc.c NR_CPUS: Replace NR_CPUS in arch/x86/kernel/cpu/mcheck/mce_64.c cpumask: Optimize cpumask_of_cpu in lib/smp_processor_id.c, fix cpumask: Use optimized CPUMASK_ALLOC macros in the centrino_target cpumask: Provide a generic set of CPUMASK_ALLOC macros cpumask: Optimize cpumask_of_cpu in lib/smp_processor_id.c cpumask: Optimize cpumask_of_cpu in kernel/time/tick-common.c cpumask: Optimize cpumask_of_cpu in drivers/misc/sgi-xp/xpc_main.c cpumask: Optimize cpumask_of_cpu in arch/x86/kernel/ldt.c cpumask: Optimize cpumask_of_cpu in arch/x86/kernel/io_apic_64.c cpumask: Replace cpumask_of_cpu with cpumask_of_cpu_ptr Revert "cpumask: introduce new APIs" cpumask: make for_each_cpu_mask a bit smaller net: Pass reference to cpumask variable in net/sunrpc/svc.c ... Fix up trivial conflicts in drivers/cpufreq/cpufreq.c manually
| * clocksource/events: use performance variant for_each_cpu_mask_nrMike Travis2008-05-23
| | | | | | | | | | | | | | | | | | | | | | Change references from for_each_cpu_mask to for_each_cpu_mask_nr where appropriate Reviewed-by: Paul Jackson <pj@sgi.com> Reviewed-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | sysdev: Pass the attribute to the low level sysdev show/store functionAndi Kleen2008-07-22
|/ | | | | | | | | | | | | | | | | | | | | | This allow to dynamically generate attributes and share show/store functions between attributes. Right now most attributes are generated by special macros and lots of duplicated code. With the attribute passed it's instead possible to attach some data to the attribute and then use that in shared low level functions to do different things. I need this for the dynamically generated bank attributes in the x86 machine check code, but it'll allow some further cleanups. I converted all users in tree to the new show/store prototype. It's a single huge patch to avoid unbisectable sections. Runtime tested: x86-32, x86-64 Compiled only: ia64, powerpc Not compile tested/only grep converted: sh, arm, avr32 Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* clocksource: allow read access to available/current_clocksourceHeiko Carstens2008-05-03
| | | | | | | | | | There is no harm, when users can read the info and we ask often enough during debugging for this kind of information. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Stultz <johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource: Fix permissions for available_clocksourceHeiko Carstens2008-05-03
| | | | | | | | | | | | File permissions for /sys/devices/system/clocksource/clocksource0/available_clocksource are 600 which allows write access. But this is in fact a read only file. So change permissions to 400. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: John Stultz <johnstul@us.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrtLinus Torvalds2008-04-18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt: clocksource: make clocksource watchdog cycle through online CPUs Documentation: move timer related documentation to a single place clockevents: optimise tick_nohz_stop_sched_tick() a bit locking: remove unused double_spin_lock() hrtimers: simplify lockdep handling timers: simplify lockdep handling posix-timers: fix shadowed variables timer_list: add annotations to workqueue.c hrtimer: use nanosleep specific restart_block fields hrtimer: add nanosleep specific restart_block member
| * clocksource: make clocksource watchdog cycle through online CPUsAndi Kleen2008-04-17
| | | | | | | | | | | | | | | | | | | | This way it checks if the clocks are synchronized between CPUs too. This might be able to detect slowly drifting TSCs which only go wrong over longer time. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | kgdb: clocksource watchdogJason Wessel2008-04-17
|/ | | | | | | | In order to not trip the clocksource watchdog, kgdb must touch the clocksource watchdog on the return to normal system run state. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* clocksource: revert: use init_timer_deferrable for clocksource_watchdogThomas Gleixner2008-03-25
| | | | | | | | | | | | | | | | | | | | Revert commit 1077f5a917b7c630231037826b344b2f7f5b903f Author: Parag Warudkar <parag.warudkar@gmail.com> Date: Wed Jan 30 13:30:01 2008 +0100 clocksource.c: use init_timer_deferrable for clocksource_watchdog clocksource_watchdog can use a deferrable timer - reduces wakeups from idle per second. The watchdog timer needs to run with the specified interval. Otherwise it will miss the possible wrap of the watchdog clocksource. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
* revert "clocksource: make clocksource watchdog cycle through online CPUs"Andrew Morton2008-03-19
| | | | | | | | | | | | | | | | | | | | | Revert commit 1ada5cba6a0318f90e45b38557e7b5206a9cba38 ("clocksource: make clocksource watchdog cycle through online CPUs") due to the regression reported by Gabriel C at http://lkml.org/lkml/2008/2/24/281 (short vesion: it makes TSC be marked as always unstable on his machine). Cc: Andi Kleen <ak@suse.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Robert Hancock <hancockr@shaw.ca> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Gabriel C <nix.or.die@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* clocksource: remove redundant codeLi Zefan2008-02-08
| | | | | | | | | | | | Flag CLOCK_SOURCE_WATCHDOG is cleared twice. Note clocksource_change_rating() won't do anyting with the cs flag. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* time: fix sysfs_show_{available,current}_clocksources() buffer overflow problemMiao Xie2008-02-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I found that there is a buffer overflow problem in the following code. Version: 2.6.24-rc2, File: kernel/time/clocksource.c:417-432 -------------------------------------------------------------------- static ssize_t sysfs_show_available_clocksources(struct sys_device *dev, char *buf) { struct clocksource *src; char *curr = buf; spin_lock_irq(&clocksource_lock); list_for_each_entry(src, &clocksource_list, list) { curr += sprintf(curr, "%s ", src->name); } spin_unlock_irq(&clocksource_lock); curr += sprintf(curr, "\n"); return curr - buf; } ----------------------------------------------------------------------- sysfs_show_current_clocksources() also has the same problem though in practice the size of current clocksource's name won't exceed PAGE_SIZE. I fix the bug by using snprintf according to the specification of the kernel (Version:2.6.24-rc2,File:Documentation/filesystems/sysfs.txt) Fix sysfs_show_available_clocksources() and sysfs_show_current_clocksources() buffer overflow problem with snprintf(). Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* clocksource: add unregister function to disable unusable clocksourcesThomas Gleixner2008-01-30
| | | | | | | | | On x86 the PIT might become an unusable clocksource. Add an unregister function to provide a possibilty to remove the PIT from the list of available clock sources. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* clocksource: make clocksource watchdog cycle through online CPUsAndi Kleen2008-01-30
| | | | | | | | | | This way it checks if the clocks are synchronized between CPUs too. This might be able to detect slowly drifting TSCs which only go wrong over longer time. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* clocksource.c: use init_timer_deferrable for clocksource_watchdogParag Warudkar2008-01-30
| | | | | | | | | | | clocksource_watchdog can use a deferrable timer - reduces wakeups from idle per second. Signed-off-by: Parag Warudkar <parag.warudkar@gmail.com> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Driver core: change sysdev classes to use dynamic kobject namesKay Sievers2008-01-24
| | | | | | | | | | All kobjects require a dynamically allocated name now. We no longer need to keep track if the name is statically assigned, we can just unconditionally free() all kobject names on cleanup. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* kernel/time/clocksource.c: Use list_for_each_entry instead of list_for_eachMatthias Kaehlcke2007-10-19
| | | | | | | | | | | | kernel/time/clocksource.c: Convert list_for_each to list_for_each_entry in clocksource_resume(), sysfs_override_clocksource() and show_available_clocksources() Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* clocksource: fix lock order in the resume pathThomas Gleixner2007-05-15
| | | | | | | | | | | | | lockdep complains about the lock nesting of clocksource and watchdog lock in the resume path. Change the resume marker to a bit operation and remove the lock from this path. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* clocksource: fix resume logicThomas Gleixner2007-05-09
| | | | | | | | | | | | | | | | | | | | | We need to make sure that the clocksources are resumed, when timekeeping is resumed. The current resume logic does not guarantee this. Add a resume function pointer to the clocksource struct, so clocksource drivers which need to reinitialize the clocksource can provide a resume function. Add a resume function, which calls the maybe available clocksource resume functions and resets the watchdog function, so a stable TSC can be used accross suspend/resume. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* clocksource: spelling error in watchdog codeDaniel Walker2007-05-09
| | | | | | | | There's more that need fixing, and fix my own subject spelling error too. Signed-off-by: Daniel Walker <dwalker@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] clocksource: Fix thinko in watchdog selectionThomas Gleixner2007-03-25
| | | | | | | | | | | | | | | | | The watchdog implementation excludes low res / non continuous clocksources from being selected as a watchdog reference unintentionally. Allow using jiffies/PIT as a watchdog reference as long as no better clocksource is available. This is necessary to detect TSC breakage on systems, which have no pmtimer/hpet. The main goal of the initial patch (preventing to switch to highres/nohz when no reliable fallback clocksource is available) is still guaranteed by the checks in clocksource_watchdog(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] clocksource init adjustments (fix bug #7426)john stultz2007-03-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch resolves the issue found here: http://bugme.osdl.org/show_bug.cgi?id=7426 The basic summary is: Currently we register most of i386/x86_64 clocksources at module_init time. Then we enable clocksource selection at late_initcall time. This causes some problems for drivers that use gettimeofday for init calibration routines (specifically the es1968 driver in this case), where durring module_init, the only clocksource available is the low-res jiffies clocksource. This may cause slight calibration errors, due to the small sampling time used. It should be noted that drivers that require fine grained time may not function on architectures that do not have better then jiffies resolution timekeeping (there are a few). However, this does not discount the reasonable need for such fine-grained timekeeping at init time. Thus the solution here is to register clocksources earlier (ideally when the hardware is being initialized), and then we enable clocksource selection at fs_initcall (before device_initcall). This patch should probably get some testing time in -mm, since clocksource selection is one of the most important issues for correct timekeeping, and I've only been able to test this on a few of my own boxes. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] tick-management: dyntick / highres functionalityThomas Gleixner2007-02-16
| | | | | | | | | | | | | | | | | With Ingo Molnar <mingo@elte.hu> Add functions to provide dynamic ticks and high resolution timers. The code which keeps track of jiffies and handles the long idle periods is shared between tick based and high resolution timer based dynticks. The dyntick functionality can be disabled on the kernel commandline. Provide also the infrastructure to support high resolution timers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] clocksource: Add verification (watchdog) helperThomas Gleixner2007-02-16
| | | | | | | | | | | | | | | The TSC needs to be verified against another clocksource. Instead of using hardwired assumptions of available hardware, provide a generic verification mechanism. The verification uses the best available clocksource and handles the usability for high resolution timers / dynticks of the clocksource which needs to be verified. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Simplify the registration of clocksourcesThomas Gleixner2007-02-16
| | | | | | | | | | | | | | Enqueue clocksources in rating order to make selection of the clocksource easier. Also check the match with an user override at enqueue time. Preparatory patch for the generic clocksource verification. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] kernel/time/clocksource.c needs struct task_struct on m68kMathieu Desnoyers2007-02-11
| | | | | | | | | | | | | | | | | | | kernel/time/clocksource.c needs struct task_struct on m68k. Because it uses spin_unlock_irq(), which, on m68k, uses hardirq_count(), which uses preempt_count(), which needs to dereference struct task_struct, we have to include sched.h. Because it would cause a loop inclusion, we cannot include sched.h in any other of asm-m68k/system.h, linux/thread_info.h, linux/hardirq.h, which leaves this ugly include in a C file as the only simple solution. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] clocksource: small cleanupDaniel Walker2006-12-10
| | | | | | | | | | | | Mostly changing alignment. Just some general cleanup. [akpm@osdl.org: build fix] Signed-off-by: Daniel Walker <dwalker@mvista.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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