[PATCH v4 4/5] powerpc/perf: Trace imc events detection and cpuhotplug

From: Anju T Sudhakar
Date: Tue Apr 16 2019 - 05:48:54 EST


Patch detects trace-imc events, does memory initilizations for each online
cpu, and registers cpuhotplug call-backs.

Signed-off-by: Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/perf/imc-pmu.c | 104 ++++++++++++++++++++++
arch/powerpc/platforms/powernv/opal-imc.c | 3 +
include/linux/cpuhotplug.h | 1 +
3 files changed, 108 insertions(+)

diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 7fe258e17dfe..3fe0222885bc 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -43,6 +43,11 @@ static DEFINE_PER_CPU(u64 *, thread_imc_mem);
static struct imc_pmu *thread_imc_pmu;
static int thread_imc_mem_size;

+/* Trace IMC data structures */
+static DEFINE_PER_CPU(u64 *, trace_imc_mem);
+static struct imc_pmu_ref *trace_imc_refc;
+static int trace_imc_mem_size;
+
static struct imc_pmu *imc_event_to_pmu(struct perf_event *event)
{
return container_of(event->pmu, struct imc_pmu, pmu);
@@ -1050,6 +1055,59 @@ static void thread_imc_event_del(struct perf_event *event, int flags)
imc_event_update(event);
}

+/*
+ * Allocate a page of memory for each cpu, and load LDBAR with 0.
+ */
+static int trace_imc_mem_alloc(int cpu_id, int size)
+{
+ u64 *local_mem = per_cpu(trace_imc_mem, cpu_id);
+ int phys_id = cpu_to_node(cpu_id), rc = 0;
+ int core_id = (cpu_id / threads_per_core);
+
+ if (!local_mem) {
+ local_mem = page_address(alloc_pages_node(phys_id,
+ GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
+ __GFP_NOWARN, get_order(size)));
+ if (!local_mem)
+ return -ENOMEM;
+ per_cpu(trace_imc_mem, cpu_id) = local_mem;
+
+ /* Initialise the counters for trace mode */
+ rc = opal_imc_counters_init(OPAL_IMC_COUNTERS_TRACE, __pa((void *)local_mem),
+ get_hard_smp_processor_id(cpu_id));
+ if (rc) {
+ pr_info("IMC:opal init failed for trace imc\n");
+ return rc;
+ }
+ }
+
+ /* Init the mutex, if not already */
+ trace_imc_refc[core_id].id = core_id;
+ mutex_init(&trace_imc_refc[core_id].lock);
+
+ mtspr(SPRN_LDBAR, 0);
+ return 0;
+}
+
+static int ppc_trace_imc_cpu_online(unsigned int cpu)
+{
+ return trace_imc_mem_alloc(cpu, trace_imc_mem_size);
+}
+
+static int ppc_trace_imc_cpu_offline(unsigned int cpu)
+{
+ mtspr(SPRN_LDBAR, 0);
+ return 0;
+}
+
+static int trace_imc_cpu_init(void)
+{
+ return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
+ "perf/powerpc/imc_trace:online",
+ ppc_trace_imc_cpu_online,
+ ppc_trace_imc_cpu_offline);
+}
+
/* update_pmu_ops : Populate the appropriate operations for "pmu" */
static int update_pmu_ops(struct imc_pmu *pmu)
{
@@ -1172,6 +1230,18 @@ static void cleanup_all_thread_imc_memory(void)
}
}

+static void cleanup_all_trace_imc_memory(void)
+{
+ int i, order = get_order(trace_imc_mem_size);
+
+ for_each_online_cpu(i) {
+ if (per_cpu(trace_imc_mem, i))
+ free_pages((u64)per_cpu(trace_imc_mem, i), order);
+
+ }
+ kfree(trace_imc_refc);
+}
+
/* Function to free the attr_groups which are dynamically allocated */
static void imc_common_mem_free(struct imc_pmu *pmu_ptr)
{
@@ -1213,6 +1283,11 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE);
cleanup_all_thread_imc_memory();
}
+
+ if (pmu_ptr->domain == IMC_DOMAIN_TRACE) {
+ cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE);
+ cleanup_all_trace_imc_memory();
+ }
}

/*
@@ -1295,6 +1370,27 @@ static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent,

thread_imc_pmu = pmu_ptr;
break;
+ case IMC_DOMAIN_TRACE:
+ /* Update the pmu name */
+ pmu_ptr->pmu.name = kasprintf(GFP_KERNEL, "%s%s", s, "_imc");
+ if (!pmu_ptr->pmu.name)
+ return -ENOMEM;
+
+ nr_cores = DIV_ROUND_UP(num_possible_cpus(), threads_per_core);
+ trace_imc_refc = kcalloc(nr_cores, sizeof(struct imc_pmu_ref),
+ GFP_KERNEL);
+ if (!trace_imc_refc)
+ return -ENOMEM;
+
+ trace_imc_mem_size = pmu_ptr->counter_mem_size;
+ for_each_online_cpu(cpu) {
+ res = trace_imc_mem_alloc(cpu, trace_imc_mem_size);
+ if (res) {
+ cleanup_all_trace_imc_memory();
+ goto err;
+ }
+ }
+ break;
default:
return -EINVAL;
}
@@ -1367,6 +1463,14 @@ int init_imc_pmu(struct device_node *parent, struct imc_pmu *pmu_ptr, int pmu_id
goto err_free_mem;
}

+ break;
+ case IMC_DOMAIN_TRACE:
+ ret = trace_imc_cpu_init();
+ if (ret) {
+ cleanup_all_trace_imc_memory();
+ goto err_free_mem;
+ }
+
break;
default:
return -EINVAL; /* Unknown domain */
diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
index 58a07948c76e..dedc9ae22662 100644
--- a/arch/powerpc/platforms/powernv/opal-imc.c
+++ b/arch/powerpc/platforms/powernv/opal-imc.c
@@ -284,6 +284,9 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
case IMC_TYPE_THREAD:
domain = IMC_DOMAIN_THREAD;
break;
+ case IMC_TYPE_TRACE:
+ domain = IMC_DOMAIN_TRACE;
+ break;
default:
pr_warn("IMC Unknown Device type \n");
domain = -1;
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index e78281d07b70..c3413d9b8348 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -170,6 +170,7 @@ enum cpuhp_state {
CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE,
CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
+ CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
CPUHP_AP_WATCHDOG_ONLINE,
CPUHP_AP_WORKQUEUE_ONLINE,
CPUHP_AP_RCUTREE_ONLINE,
--
2.17.2