Commit graph

29 commits

Author SHA1 Message Date
Heiko Carstens
4f95f81a48 clocksource: allow read access to available/current_clocksource
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>
2008-05-03 18:11:48 +02:00
Heiko Carstens
4359a023a8 clocksource: Fix permissions for available_clocksource
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>
2008-05-03 18:11:48 +02:00
Linus Torvalds
73e3e6481f Merge git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt
* 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
2008-04-18 08:37:41 -07:00
Jason Wessel
7c3078b637 kgdb: clocksource watchdog
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>
2008-04-17 20:05:38 +02:00
Andi Kleen
6993fc5bbc clocksource: make clocksource watchdog cycle through online CPUs
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>
2008-04-17 12:22:31 +02:00
Thomas Gleixner
898a19de15 clocksource: revert: use init_timer_deferrable for clocksource_watchdog
Revert

commit 1077f5a917
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
2008-03-25 20:13:25 +01:00
Andrew Morton
3150e63df4 revert "clocksource: make clocksource watchdog cycle through online CPUs"
Revert commit 1ada5cba6a ("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>
2008-03-19 18:53:37 -07:00
Li Zefan
818c357802 clocksource: remove redundant code
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>
2008-02-08 09:22:29 -08:00
Miao Xie
5e2cb1018a time: fix sysfs_show_{available,current}_clocksources() buffer overflow problem
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>
2008-02-06 10:41:03 -08:00
Thomas Gleixner
4713e22ce8 clocksource: add unregister function to disable unusable clocksources
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>
2008-01-30 13:30:02 +01:00
Andi Kleen
1ada5cba6a clocksource: make clocksource watchdog cycle through online CPUs
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>
2008-01-30 13:30:02 +01:00
Parag Warudkar
1077f5a917 clocksource.c: use init_timer_deferrable for clocksource_watchdog
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>
2008-01-30 13:30:01 +01:00
Kay Sievers
af5ca3f4ec Driver core: change sysdev classes to use dynamic kobject names
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>
2008-01-24 20:40:40 -08:00
Matthias Kaehlcke
2e1975868a kernel/time/clocksource.c: Use list_for_each_entry instead of list_for_each
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>
2007-10-19 11:53:38 -07:00
Thomas Gleixner
8f89441b37 clocksource: fix lock order in the resume path
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>
2007-05-15 08:54:00 -07:00
Thomas Gleixner
b52f52a093 clocksource: fix resume logic
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>
2007-05-09 12:30:56 -07:00
Daniel Walker
35c35d1afa clocksource: spelling error in watchdog code
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>
2007-05-09 12:30:49 -07:00
Thomas Gleixner
948ac6d71c [PATCH] clocksource: Fix thinko in watchdog selection
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>
2007-03-25 14:57:34 -07:00
john stultz
6bb74df481 [PATCH] clocksource init adjustments (fix bug #7426)
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>
2007-03-05 07:57:53 -08:00
Thomas Gleixner
79bf2bb335 [PATCH] tick-management: dyntick / highres functionality
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>
2007-02-16 08:13:59 -08:00
Thomas Gleixner
5d8b34fdcb [PATCH] clocksource: Add verification (watchdog) helper
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>
2007-02-16 08:13:57 -08:00
Thomas Gleixner
92c7e00254 [PATCH] Simplify the registration of clocksources
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>
2007-02-16 08:13:57 -08:00
Mathieu Desnoyers
dc29a3657b [PATCH] kernel/time/clocksource.c needs struct task_struct on m68k
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>
2007-02-11 10:51:20 -08:00
Daniel Walker
f5f1a24a2c [PATCH] clocksource: small cleanup
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>
2006-12-10 09:57:22 -08:00
Daniel Walker
2b0137001d [PATCH] clocksource: add usage of CONFIG_SYSFS
Simply adds some ifdefs to remove clocksoure sysfs code when CONFIG_SYSFS
isn't turn on.

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>
2006-12-10 09:57:22 -08:00
john stultz
a275254975 [PATCH] time: rename clocksource functions
As suggested by Roman Zippel, change clocksource functions to use
clocksource_xyz rather then xyz_clocksource to avoid polluting the
namespace.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:21 -07:00
john stultz
5d0cf410e9 [PATCH] Time: i386 Clocksource Drivers
Implement the time sources for i386 (acpi_pm, cyclone, hpet, pit, and tsc).
With this patch, the conversion of the i386 arch to the generic timekeeping
code should be complete.

The patch should be fairly straight forward, only adding the new clocksources.

[hirofumi@mail.parknet.co.jp: acpi_pm cleanup]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:21 -07:00
john stultz
ad596171ed [PATCH] Time: Use clocksource infrastructure for update_wall_time
Modify the update_wall_time function so it increments time using the
clocksource abstraction instead of jiffies.  Since the only clocksource driver
currently provided is the jiffies clocksource, this should result in no
functional change.  Additionally, a timekeeping_init and timekeeping_resume
function has been added to initialize and maintain some of the new timekeping
state.

[hirofumi@mail.parknet.co.jp: fixlet]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:20 -07:00
john stultz
734efb467b [PATCH] Time: Clocksource Infrastructure
This introduces the clocksource management infrastructure.  A clocksource is a
driver-like architecture generic abstraction of a free-running counter.  This
code defines the clocksource structure, and provides management code for
registering, selecting, accessing and scaling clocksources.

Additionally, this includes the trivial jiffies clocksource, a lowest common
denominator clocksource, provided mainly for use as an example.

[hirofumi@mail.parknet.co.jp: Don't enable IRQ too early]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:20 -07:00