[PATCH v2 5/5] powerpc/perf: Trace imc PMU functions

From: Anju T Sudhakar
Date: Fri Dec 14 2018 - 04:11:47 EST


Add PMU functions to support trace-imc.

Signed-off-by: Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/perf/imc-pmu.c | 175 ++++++++++++++++++++++++++++++++++++
1 file changed, 175 insertions(+)

diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 1f09265c8fb0..32ff0e449fca 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -1120,6 +1120,173 @@ static int trace_imc_cpu_init(void)
ppc_trace_imc_cpu_offline);
}

+static u64 get_trace_imc_event_base_addr(void)
+{
+ return (u64)per_cpu(trace_imc_mem, smp_processor_id());
+}
+
+/*
+ * Function to parse trace-imc data obtained
+ * and to prepare the perf sample.
+ */
+static int trace_imc_prepare_sample(struct trace_imc_data *mem,
+ struct perf_sample_data *data,
+ u64 *prev_tb,
+ struct perf_event_header *header,
+ struct perf_event *event)
+{
+ /* Sanity checks for a valid record */
+ if (be64_to_cpu(READ_ONCE(mem->tb1)) > *prev_tb)
+ *prev_tb = be64_to_cpu(READ_ONCE(mem->tb1));
+ else
+ return -EINVAL;
+
+ if ((be64_to_cpu(READ_ONCE(mem->tb1)) & IMC_TRACE_RECORD_TB1_MASK) !=
+ be64_to_cpu(READ_ONCE(mem->tb2)))
+ return -EINVAL;
+
+ /* Prepare perf sample */
+ data->ip = be64_to_cpu(READ_ONCE(mem->ip));
+ data->period = event->hw.last_period;
+
+ header->type = PERF_RECORD_SAMPLE;
+ header->size = sizeof(*header) + event->header_size;
+ header->misc = 0;
+
+ if (is_kernel_addr(data->ip))
+ header->misc |= PERF_RECORD_MISC_KERNEL;
+ else
+ header->misc |= PERF_RECORD_MISC_USER;
+
+ perf_event_header__init_id(header, data, event);
+
+ return 0;
+}
+
+static void dump_trace_imc_data(struct perf_event *event)
+{
+ struct trace_imc_data *mem;
+ int i, ret;
+ u64 prev_tb = 0;
+
+ mem = (struct trace_imc_data *)get_trace_imc_event_base_addr();
+ for (i = 0; i < (trace_imc_mem_size / sizeof(struct trace_imc_data));
+ i++, mem++) {
+ struct perf_sample_data data;
+ struct perf_event_header header;
+
+ ret = trace_imc_prepare_sample(mem, &data, &prev_tb, &header, event);
+ if (ret) /* Exit, if not a valid record */
+ break;
+ else {
+ /* If this is a valid record, create the sample */
+ struct perf_output_handle handle;
+
+ if (perf_output_begin(&handle, event, header.size))
+ return;
+
+ perf_output_sample(&handle, &header, &data, event);
+ perf_output_end(&handle);
+ }
+ }
+}
+
+static int trace_imc_event_add(struct perf_event *event, int flags)
+{
+ /* Enable the sched_task to start the engine */
+ perf_sched_cb_inc(event->ctx->pmu);
+ return 0;
+}
+
+static void trace_imc_event_read(struct perf_event *event)
+{
+ dump_trace_imc_data(event);
+}
+
+static void trace_imc_event_stop(struct perf_event *event, int flags)
+{
+ trace_imc_event_read(event);
+}
+
+static void trace_imc_event_start(struct perf_event *event, int flags)
+{
+ return;
+}
+
+static void trace_imc_event_del(struct perf_event *event, int flags)
+{
+ perf_sched_cb_dec(event->ctx->pmu);
+}
+
+void trace_imc_pmu_sched_task(struct perf_event_context *ctx,
+ bool sched_in)
+{
+ int core_id = smp_processor_id() / threads_per_core;
+ struct imc_pmu_ref *ref;
+ u64 local_mem, ldbar_value;
+
+ /* Set trace-imc bit in ldbar and load ldbar with per-thread memory address */
+ local_mem = get_trace_imc_event_base_addr();
+ ldbar_value = ((u64)local_mem & THREAD_IMC_LDBAR_MASK) | TRACE_IMC_ENABLE;
+
+ ref = &core_imc_refc[core_id];
+ if (!ref)
+ return;
+
+ if (sched_in) {
+ mtspr(SPRN_LDBAR, ldbar_value);
+ mutex_lock(&ref->lock);
+ if (ref->refc == 0) {
+ if (opal_imc_counters_start(OPAL_IMC_COUNTERS_TRACE,
+ get_hard_smp_processor_id(smp_processor_id()))) {
+ mutex_unlock(&ref->lock);
+ pr_err("trace-imc: Unable to start the counters for core %d\n", core_id);
+ mtspr(SPRN_LDBAR, 0);
+ return;
+ }
+ }
+ ++ref->refc;
+ mutex_unlock(&ref->lock);
+ } else {
+ mtspr(SPRN_LDBAR, 0);
+ mutex_lock(&ref->lock);
+ ref->refc--;
+ if (ref->refc == 0) {
+ if (opal_imc_counters_stop(OPAL_IMC_COUNTERS_TRACE,
+ get_hard_smp_processor_id(smp_processor_id()))) {
+ mutex_unlock(&ref->lock);
+ pr_err("trace-imc: Unable to stop the counters for core %d\n", core_id);
+ return;
+ }
+ } else if (ref->refc < 0) {
+ ref->refc = 0;
+ }
+ mutex_unlock(&ref->lock);
+ }
+ return;
+}
+
+static int trace_imc_event_init(struct perf_event *event)
+{
+ struct task_struct *target;
+
+ if (event->attr.type != event->pmu->type)
+ return -ENOENT;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ /* Return if this is a couting event */
+ if (event->attr.sample_period == 0)
+ return -ENOENT;
+
+ event->hw.idx = -1;
+ target = event->hw.target;
+
+ event->pmu->task_ctx_nr = perf_hw_context;
+ return 0;
+}
+
/* update_pmu_ops : Populate the appropriate operations for "pmu" */
static int update_pmu_ops(struct imc_pmu *pmu)
{
@@ -1149,6 +1316,14 @@ static int update_pmu_ops(struct imc_pmu *pmu)
pmu->pmu.cancel_txn = thread_imc_pmu_cancel_txn;
pmu->pmu.commit_txn = thread_imc_pmu_commit_txn;
break;
+ case IMC_DOMAIN_TRACE:
+ pmu->pmu.event_init = trace_imc_event_init;
+ pmu->pmu.add = trace_imc_event_add;
+ pmu->pmu.del = trace_imc_event_del;
+ pmu->pmu.start = trace_imc_event_start;
+ pmu->pmu.stop = trace_imc_event_stop;
+ pmu->pmu.read = trace_imc_event_read;
+ pmu->pmu.sched_task = trace_imc_pmu_sched_task;
default:
break;
}
--
2.17.1