linux/arch/arm/include/asm/perf_event.h
Peter Zijlstra e360adbe29 irq_work: Add generic hardirq context callbacks
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 <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-18 19:58:50 +02:00

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C

/*
* linux/arch/arm/include/asm/perf_event.h
*
* Copyright (C) 2009 picoChip Designs Ltd, Jamie Iles
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#ifndef __ARM_PERF_EVENT_H__
#define __ARM_PERF_EVENT_H__
/* ARM performance counters start from 1 (in the cp15 accesses) so use the
* same indexes here for consistency. */
#define PERF_EVENT_INDEX_OFFSET 1
/* ARM perf PMU IDs for use by internal perf clients. */
enum arm_perf_pmu_ids {
ARM_PERF_PMU_ID_XSCALE1 = 0,
ARM_PERF_PMU_ID_XSCALE2,
ARM_PERF_PMU_ID_V6,
ARM_PERF_PMU_ID_V6MP,
ARM_PERF_PMU_ID_CA8,
ARM_PERF_PMU_ID_CA9,
ARM_NUM_PMU_IDS,
};
extern enum arm_perf_pmu_ids
armpmu_get_pmu_id(void);
extern int
armpmu_get_max_events(void);
#endif /* __ARM_PERF_EVENT_H__ */