arch/sh/kernel/perf_event.c

Source file repositories/reference/linux-study-clean/arch/sh/kernel/perf_event.c

File Facts

System
Linux kernel
Corpus path
arch/sh/kernel/perf_event.c
Extension
.c
Size
8464 bytes
Lines
364
Domain
Architecture Layer
Bucket
arch/sh
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

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)];
};

DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);

static struct sh_pmu *sh_pmu __read_mostly;

/* Number of perf_events counting hardware events */
static atomic_t num_events;
/* Used to avoid races in calling reserve/release_pmc_hardware */
static DEFINE_MUTEX(pmc_reserve_mutex);

/*
 * Stub these out for now, do something more profound later.
 */
int reserve_pmc_hardware(void)
{
	return 0;
}

void release_pmc_hardware(void)
{
}

static inline int sh_pmu_initialized(void)
{
	return !!sh_pmu;
}

/*
 * Release the PMU if this is the last perf_event.
 */
static void hw_perf_event_destroy(struct perf_event *event)
{
	if (!atomic_add_unless(&num_events, -1, 1)) {
		mutex_lock(&pmc_reserve_mutex);
		if (atomic_dec_return(&num_events) == 0)
			release_pmc_hardware();
		mutex_unlock(&pmc_reserve_mutex);
	}
}

static int hw_perf_cache_event(int config, int *evp)
{
	unsigned long type, op, result;
	int ev;

	if (!sh_pmu->cache_events)
		return -EINVAL;

	/* unpack config */
	type = config & 0xff;
	op = (config >> 8) & 0xff;
	result = (config >> 16) & 0xff;

	if (type >= PERF_COUNT_HW_CACHE_MAX ||
	    op >= PERF_COUNT_HW_CACHE_OP_MAX ||
	    result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
		return -EINVAL;

	ev = (*sh_pmu->cache_events)[type][op][result];
	if (ev == 0)
		return -EOPNOTSUPP;
	if (ev == -1)
		return -EINVAL;
	*evp = ev;
	return 0;
}

static int __hw_perf_event_init(struct perf_event *event)
{
	struct perf_event_attr *attr = &event->attr;
	struct hw_perf_event *hwc = &event->hw;
	int config = -1;
	int err;

	if (!sh_pmu_initialized())
		return -ENODEV;

	/*
	 * See if we need to reserve the counter.
	 *
	 * If no events are currently in use, then we have to take a
	 * mutex to ensure that we don't race with another task doing
	 * reserve_pmc_hardware or release_pmc_hardware.
	 */
	err = 0;

Annotation

Implementation Notes