path: root/arch/sparc/kernel/perf_event.c

/* Performance event support for sparc64.
 *
 * Copyright (C) 2009 David S. Miller <davem@davemloft.net>
 *
 * This code is based almost entirely upon the x86 perf event
 * code, which is:
 *
 *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
 *  Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
 *  Copyright (C) 2009 Jaswinder Singh Rajput
 *  Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
 *  Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
 */

#include <linux/perf_event.h>
#include <linux/kprobes.h>
#include <linux/kernel.h>
#include <linux/kdebug.h>
#include <linux/mutex.h>

#include <asm/cpudata.h>
#include <asm/atomic.h>
#include <asm/nmi.h>
#include <asm/pcr.h>

/* Sparc64 chips have two performance counters, 32-bits each, with
 * overflow interrupts generated on transition from 0xffffffff to 0.
 * The counters are accessed in one go using a 64-bit register.
 *
 * Both counters are controlled using a single control register.  The
 * only way to stop all sampling is to clear all of the context (user,
 * supervisor, hypervisor) sampling enable bits.  But these bits apply
 * to both counters, thus the two counters can't be enabled/disabled
 * individually.
 *
 * The control register has two event fields, one for each of the two
 * counters.  It's thus nearly impossible to have one counter going
 * while keeping the other one stopped.  Therefore it is possible to
 * get overflow interrupts for counters not currently "in use" and
 * that condition must be checked in the overflow interrupt handler.
 *
 * So we use a hack, in that we program inactive counters with the
 * "sw_count0" and "sw_count1" events.  These count how many times
 * the instruction "sethi %hi(0xfc000), %g0" is executed.  It's an
 * unusual way to encode a NOP and therefore will not trigger in
 * normal code.
 */

#define MAX_HWEVENTS			2
#define MAX_PERIOD			((1UL << 32) - 1)

#define PIC_UPPER_INDEX			0
#define PIC_LOWER_INDEX			1

struct cpu_hw_events {
	struct perf_event	*events[MAX_HWEVENTS];
	unsigned long		used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
	unsigned long		active_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
	u64			pcr;
	int			enabled;
};
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, };

struct perf_event_map {
	u16	encoding;
	u8	pic_mask;
#define PIC_NONE	0x00
#define PIC_UPPER	0x01
#define PIC_LOWER	0x02
};

static unsigned long perf_event_encode(const struct perf_event_map *pmap)
{
	return ((unsigned long) pmap->encoding << 16) | pmap->pic_mask;
}

static void perf_event_decode(unsigned long val, u16 *enc, u8 *msk)
{
	*msk = val & 0xff;
	*enc = val >> 16;
}

#define C(x) PERF_COUNT_HW_CACHE_##x

#define CACHE_OP_UNSUPPORTED	0xfffe
#define CACHE_OP_NONSENSE	0xffff

typedef struct perf_event_map cache_map_t
				[PERF_COUNT_HW_CACHE_MAX]
				[PERF_COUNT_HW_CACHE_OP_MAX]
				[PERF_COUNT_HW_CACHE_RESULT_MAX];

struct sparc_pmu {
	const struct perf_event_map	*(*event_map)(int);
	const cache_map_t		*cache_map;
	int				max_events;
	int				upper_shift;
	int				lower_shift;
	int				event_mask;
	int				hv_bit;
	int				irq_bit;
	int				upper_nop;
	int				lower_nop;
};

static const struct perf_event_map ultra3_perfmon_event_map[] = {
	[PERF_COUNT_HW_CPU_CYCLES] = { 0x0000, PIC_UPPER | PIC_LOWER },
	[PERF_COUNT_HW_INSTRUCTIONS] = { 0x0001, PIC_UPPER | PIC_LOWER },
	[PERF_COUNT_HW_CACHE_REFERENCES] = { 0x0009, PIC_LOWER },
	[PERF_COUNT_HW_CACHE_MISSES] = { 0x0009, PIC_UPPER },
};

static const struct perf_event_map *ultra3_event_map(int event_id)
{
	return &ultra3_perfmon_event_map[event_id];
}

static const cache_map_t ultra3_cache_map = {
[C(L1D)] = {
	[C(OP_READ)] = {
		[C(RESULT_ACCESS)] = { 0x09, PIC_LOWER, },
		[C(RESULT_MISS)] = { 0x09, PIC_UPPER, },
	},
	[C(OP_WRITE)] = {
		[C(RESULT_ACCESS)] = { 0x0a, PIC_LOWER },
		[C(RESULT_MISS)] = { 0x0a, PIC_UPPER },
	},
	[C(OP_PREFETCH)] = {
		[C(RESULT_ACCESS)] = { CACHE_OP_UNSUPPORTED },
		[C(RESULT_MISS)] = { CACHE_OP_UNSUPPORTED },
	},
},
[C(L1I)] = {
	[C(OP_READ)] = {
		[C(RESULT_ACCESS)] = { 0x09, PIC_LOWER, },
		[C(RESULT_MISS)] = { 0x09, PIC_UPPER, },
	},
	[ C(OP_WRITE) ] = {
		[ C(RESULT_ACCESS) ] = { CACHE_OP_NONSENSE },
		[ C(RESULT_MISS)   ] =