void intel_bts_enable_local(void)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
if (bts->handle.event && bts->started)
__bts_event_start(bts->handle.event);
}
static void bts_event_start(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_buffer *buf;
buf = perf_aux_output_begin(&bts->handle, event);
if (!buf)
goto fail_stop;
if (bts_buffer_reset(buf, &bts->handle))
goto fail_end_stop;
bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;
bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum;
bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold;
event->hw.itrace_started = 1;
event->hw.state = 0;
__bts_event_start(event);
return;
fail_end_stop:
perf_aux_output_end(&bts->handle, 0, false);
fail_stop:
event->hw.state = PERF_HES_STOPPED;
}
static void bts_event_start(struct perf_event *event, int flags)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
__bts_event_start(event);
/* PMI handler: this counter is running and likely generating PMIs */
ACCESS_ONCE(bts->started) = 1;
}
void intel_bts_enable_local(void)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
int state = READ_ONCE(bts->state);
/*
* Here we transition from INACTIVE to ACTIVE;
* if we instead are STOPPED from the interrupt handler,
* stay that way. Can't be ACTIVE here though.
*/
if (WARN_ON_ONCE(state == BTS_STATE_ACTIVE))
return;
if (state == BTS_STATE_STOPPED)
return;
if (bts->handle.event)
__bts_event_start(bts->handle.event);
}