clocksource: Cleanup clocksource selection

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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>

...

This commit is contained in:

Martin Schwidefsky 2009-08-14 15:47:21 +02:00 • committed by Thomas Gleixner

parent 1be3967948

commit f1b82746c1

5 changed files with 64 additions and 86 deletions

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4

arch/s390/kernel/time.c

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2

include/linux/clocksource.h

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138

kernel/time/clocksource.c

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6

kernel/time/jiffies.c

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4

kernel/time/timekeeping.c

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