linux.git/arch/alpha/kernel/time.c, branch v2.6.37

irq_work: Add generic hardirq context callbacks

2010-10-18T17:58:50+00:00

Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.

Signed-off-by: Peter Zijlstra 
Acked-by: Kyle McMartin 
Acked-by: Martin Schwidefsky 
[ various fixes ]
Signed-off-by: Huang Ying 
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar

alpha: Shift perf event pending work earlier in timer interrupt

2010-09-19T03:06:19+00:00

Pending work from the performance event subsystem is executed in
the timer interrupt.  This patch shifts the call to
perf_event_do_pending() before the call to update_process_times()
as the latter may call back into the perf event subsystem and it
is prudent to have the pending work executed first.

Signed-off-by: Michael Cree 
Signed-off-by: Matt Turner

alpha: implement HW performance events on the EV67 and later CPUs

2010-08-10T03:45:04+00:00

This implements hardware performance events for the EV67 and later CPUs
within the Linux performance events subsystem.  Only using the performance
monitoring unit in HP/Compaq's so called "Aggregrate mode" is supported.

The code has been implemented in a manner that makes extension to other
older Alpha CPUs relatively straightforward should some mug wish to
indulge themselves.

Signed-off-by: Michael Cree 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Jay Estabrook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Convert alpha to use clocksources instead of arch_gettimeoffset

2010-05-25T22:40:27+00:00

Alpha has a tsc like rpcc counter that it uses to manage time.
This can be converted to an actual clocksource instead of utilizing
the arch_gettimeoffset method that is really only there for legacy
systems with no continuous counter.

Further cleanups could be made if alpha converted to the clockevent
model.

CC: Thomas Gleixner 
CC: Richard Henderson 
Acked-by: Ivan Kokshaysky 
Tested-by: Ivan Kokshaysky 
Signed-off-by: Matt Turner 
Signed-off-by: John Stultz

alpha: Convert alpha to use read/update_persistent_clock

2010-03-13T00:14:08+00:00

This patch converts the alpha architecture to use the generic
read_persistent_clock and update_persistent_clock interfaces, reducing
the amount of arch specific code we have to maintain, and allowing for
further cleanups in the future.

I have not built or tested this patch, so help from arch maintainers
would be appreciated.

igned-off-by: John Stultz 
Cc: Richard Henderson 
Cc: Andrew Morton 
LKML-Reference: <1267675049-12337-2-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner

alpha: convert to use arch_gettimeoffset()

2009-09-22T14:17:43+00:00

Converts alpha to use GENERIC_TIME via the arch_getoffset()
infrastructure, reducing the amount of arch specific code we need to
maintain.

I suspect the alpha arch could even be further improved to provide and
rpcc() based clocksource, but not having the hardware, I don't feel
comfortable attempting the more complicated conversion (but I'd be glad to
help if anyone else is interested).

[akpm@linux-foundation.org: fix build]
Signed-off-by: John Stultz 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

alpha: fix RTC on marvel

2009-01-16T00:39:40+00:00

Unlike other alphas, marvel doesn't have real PC-style CMOS clock hardware
- RTC accesses are emulated via PAL calls.  Unfortunately, for unknown
reason these calls work only on CPU #0.  So current implementation for
arbitrary CPU makes CMOS_READ/WRITE to be executed on CPU #0 via IPI.
However, for obvious reason this doesn't work with standard
get/set_rtc_time() functions, where a bunch of CMOS accesses is done with
disabled interrupts.

Solved by making the IPI calls for entire get/set_rtc_time() functions,
not for individual CMOS accesses.  Which is also a lot more effective
performance-wise.

The patch is largely based on the code from Jay Estabrook.
My changes:
- tweak asm-generic/rtc.h by adding a couple of #defines to
  avoid a massive code duplication in arch/alpha/include/asm/rtc.h;
- sys_marvel.c: fix get/set_rtc_time() return values (Jay's FIXMEs).

NOTE: this fixes *only* LIB_RTC drivers.  Legacy (CONFIG_RTC) driver
wont't work on marvel.  Actually I think that we should just disable
CONFIG_RTC on alpha (maybe in 2.6.30?), like most other arches - AFAIK,
all modern distributions use LIB_RTC anyway.

Signed-off-by: Ivan Kokshaysky 
Cc: Richard Henderson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

alpha: use bcd2bin/bin2bcd

2008-10-20T15:52:41+00:00

Change alpha to use the new bcd2bin/bin2bcd functions instead of the
obsolete BCD_TO_BIN/BIN_TO_BCD macros.

Signed-off-by: Adrian Bunk 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

xtime_lock vs update_process_times

2008-02-13T21:29:25+00:00

Commit d3d74453c34f8fd87674a8cf5b8a327c68f22e99 ("hrtimer: fixup the
HRTIMER_CB_IRQSAFE_NO_SOFTIRQ fallback") broke several archs, and since
only Russell bothered to merge the fix, and Greg to ACK his arch, I'm
sending this for merger.

I have confirmation that the Alpha bit results in a booting kernel.
That leaves: blackfin, frv, sh and sparc untested.

The deadlock in question was found by Russell:

  IRQ handle
    -> timer_tick() - xtime seqlock held for write
      -> update_process_times()
        -> run_local_timers()
          -> hrtimer_run_queues()
            -> hrtimer_get_softirq_time() - tries to get a read lock

Now, Thomas assures me the fix is trivial, only do_timer() needs to be
done under the xtime_lock, and update_process_times() can savely be
removed from under it.

Signed-off-by: Peter Zijlstra 
Acked-by: Greg Ungerer 
CC: Richard Henderson 
CC: Bryan Wu 
CC: David Howells 
CC: Paul Mundt 
CC: William Irwin 
Acked-by: Ingo Molnar 
Acked-by: Ivan Kokshaysky 
Signed-off-by: Linus Torvalds

alpha: fix trivial section mismatch warnings

2007-07-16T16:05:37+00:00

Fix the following section mismatch warnings:
WARNING: arch/alpha/kernel/built-in.o(.text+0x7c78): Section mismatch: reference to .init.text:init_rtc_irq (between 'common_init_rtc' and 'timer_interrupt')
WARNING: arch/alpha/kernel/built-in.o(.text+0x7c7c): Section mismatch: reference to .init.text:init_rtc_irq (between 'common_init_rtc' and 'timer_interrupt')
WARNING: arch/alpha/kernel/built-in.o(.data+0x2c30): Section mismatch: reference to .init.text:srm_console_setup (between 'srmcons' and 'tsunami_pci_ops')

In all three cases functions marked __init was called outside __init context.
So the fix was to just drop the __init attribute.

Signed-off-by: Sam Ravnborg 
Cc: Meelis Roos 
Cc: Ivan Kokshaysky 
Cc: Richard Henderson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds