--- /dev/null
+/*
+ * In-Memory Collection (IMC) Performance Monitor counter support.
+ *
+ * Copyright (C) 2017 Madhavan Srinivasan, IBM Corporation.
+ * (C) 2017 Anju T Sudhakar, IBM Corporation.
+ * (C) 2017 Hemant K Shaw, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or later version.
+ */
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+#include <asm/opal.h>
+#include <asm/imc-pmu.h>
+#include <asm/cputhreads.h>
+#include <asm/smp.h>
+#include <linux/string.h>
+
+/* Nest IMC data structures and variables */
+
+/*
+ * Used to avoid races in counting the nest-pmu units during hotplug
+ * register and unregister
+ */
+static DEFINE_MUTEX(nest_init_lock);
+static DEFINE_PER_CPU(struct imc_pmu_ref *, local_nest_imc_refc);
+static struct imc_pmu *per_nest_pmu_arr[IMC_MAX_PMUS];
+static cpumask_t nest_imc_cpumask;
+struct imc_pmu_ref *nest_imc_refc;
+static int nest_pmus;
+
+struct imc_pmu *imc_event_to_pmu(struct perf_event *event)
+{
+ return container_of(event->pmu, struct imc_pmu, pmu);
+}
+
+PMU_FORMAT_ATTR(event, "config:0-40");
+PMU_FORMAT_ATTR(offset, "config:0-31");
+PMU_FORMAT_ATTR(rvalue, "config:32");
+PMU_FORMAT_ATTR(mode, "config:33-40");
+static struct attribute *imc_format_attrs[] = {
+ &format_attr_event.attr,
+ &format_attr_offset.attr,
+ &format_attr_rvalue.attr,
+ &format_attr_mode.attr,
+ NULL,
+};
+
+static struct attribute_group imc_format_group = {
+ .name = "format",
+ .attrs = imc_format_attrs,
+};
+
+/* Get the cpumask printed to a buffer "buf" */
+static ssize_t imc_pmu_cpumask_get_attr(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pmu *pmu = dev_get_drvdata(dev);
+ struct imc_pmu *imc_pmu = container_of(pmu, struct imc_pmu, pmu);
+ cpumask_t *active_mask;
+
+ /* Subsequenct patch will add more pmu types here */
+ switch(imc_pmu->domain){
+ case IMC_DOMAIN_NEST:
+ active_mask = &nest_imc_cpumask;
+ break;
+ default:
+ return 0;
+ }
+
+ return cpumap_print_to_pagebuf(true, buf, active_mask);
+}
+
+static DEVICE_ATTR(cpumask, S_IRUGO, imc_pmu_cpumask_get_attr, NULL);
+
+static struct attribute *imc_pmu_cpumask_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL,
+};
+
+static struct attribute_group imc_pmu_cpumask_attr_group = {
+ .attrs = imc_pmu_cpumask_attrs,
+};
+
+/* device_str_attr_create : Populate event "name" and string "str" in attribute */
+static struct attribute *device_str_attr_create(const char *name, const char *str)
+{
+ struct perf_pmu_events_attr *attr;
+
+ attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+ if (!attr)
+ return NULL;
+ sysfs_attr_init(&attr->attr.attr);
+
+ attr->event_str = str;
+ attr->attr.attr.name = name;
+ attr->attr.attr.mode = 0444;
+ attr->attr.show = perf_event_sysfs_show;
+
+ return &attr->attr.attr;
+}
+
+struct imc_events *imc_parse_event(struct device_node *np, const char *scale,
+ const char *unit, const char *prefix, u32 base)
+{
+ struct imc_events *event;
+ const char *s;
+ u32 reg;
+
+ event = kzalloc(sizeof(struct imc_events), GFP_KERNEL);
+ if (!event)
+ return NULL;
+
+ if (of_property_read_u32(np, "reg", ®))
+ goto error;
+ /* Add the base_reg value to the "reg" */
+ event->value = base + reg;
+
+ if (of_property_read_string(np, "event-name", &s))
+ goto error;
+
+ event->name = kasprintf(GFP_KERNEL, "%s%s", prefix, s);
+ if (!event->name)
+ goto error;
+
+ if (of_property_read_string(np, "scale", &s))
+ s = scale;
+
+ if (s) {
+ event->scale = kstrdup(s, GFP_KERNEL);
+ if (!event->scale)
+ goto error;
+ }
+
+ if (of_property_read_string(np, "unit", &s))
+ s = unit;
+
+ if (s) {
+ event->unit = kstrdup(s, GFP_KERNEL);
+ if (!event->unit)
+ goto error;
+ }
+
+ return event;
+error:
+ kfree(event->unit);
+ kfree(event->scale);
+ kfree(event->name);
+ kfree(event);
+
+ return NULL;
+}
+
+/*
+ * update_events_in_group: Update the "events" information in an attr_group
+ * and assign the attr_group to the pmu "pmu".
+ */
+static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
+{
+ struct attribute_group *attr_group;
+ struct attribute **attrs, *dev_str;
+ struct device_node *np, *pmu_events;
+ struct imc_events *ev;
+ u32 handle, base_reg;
+ int i=0, j=0, ct;
+ const char *prefix, *g_scale, *g_unit;
+ const char *ev_val_str, *ev_scale_str, *ev_unit_str;
+
+ if (!of_property_read_u32(node, "events", &handle))
+ pmu_events = of_find_node_by_phandle(handle);
+ else
+ return 0;
+
+ /* Did not find any node with a given phandle */
+ if (!pmu_events)
+ return 0;
+
+ /* Get a count of number of child nodes */
+ ct = of_get_child_count(pmu_events);
+
+ /* Get the event prefix */
+ if (of_property_read_string(node, "events-prefix", &prefix))
+ return 0;
+
+ /* Get a global unit and scale data if available */
+ if (of_property_read_string(node, "scale", &g_scale))
+ g_scale = NULL;
+
+ if (of_property_read_string(node, "unit", &g_unit))
+ g_unit = NULL;
+
+ /* "reg" property gives out the base offset of the counters data */
+ of_property_read_u32(node, "reg", &base_reg);
+
+ /* Allocate memory for the events */
+ pmu->events = kcalloc(ct, sizeof(struct imc_events), GFP_KERNEL);
+ if (!pmu->events)
+ return -ENOMEM;
+
+ ct = 0;
+ /* Parse the events and update the struct */
+ for_each_child_of_node(pmu_events, np) {
+ ev = imc_parse_event(np, g_scale, g_unit, prefix, base_reg);
+ if (ev)
+ pmu->events[ct++] = ev;
+ }
+
+ /* Allocate memory for attribute group */
+ attr_group = kzalloc(sizeof(*attr_group), GFP_KERNEL);
+ if (!attr_group)
+ return -ENOMEM;
+
+ /*
+ * Allocate memory for attributes.
+ * Since we have count of events for this pmu, we also allocate
+ * memory for the scale and unit attribute for now.
+ * "ct" has the total event structs added from the events-parent node.
+ * So allocate three times the "ct" (this includes event, event_scale and
+ * event_unit).
+ */
+ attrs = kcalloc(((ct * 3) + 1), sizeof(struct attribute *), GFP_KERNEL);
+ if (!attrs) {
+ kfree(attr_group);
+ kfree(pmu->events);
+ return -ENOMEM;
+ }
+
+ attr_group->name = "events";
+ attr_group->attrs = attrs;
+ do {
+ ev_val_str = kasprintf(GFP_KERNEL, "event=0x%x", pmu->events[i]->value);
+ dev_str = device_str_attr_create(pmu->events[i]->name, ev_val_str);
+ if (!dev_str)
+ continue;
+
+ attrs[j++] = dev_str;
+ if (pmu->events[i]->scale) {
+ ev_scale_str = kasprintf(GFP_KERNEL, "%s.scale",pmu->events[i]->name);
+ dev_str = device_str_attr_create(ev_scale_str, pmu->events[i]->scale);
+ if (!dev_str)
+ continue;
+
+ attrs[j++] = dev_str;
+ }
+
+ if (pmu->events[i]->unit) {
+ ev_unit_str = kasprintf(GFP_KERNEL, "%s.unit",pmu->events[i]->name);
+ dev_str = device_str_attr_create(ev_unit_str, pmu->events[i]->unit);
+ if (!dev_str)
+ continue;
+
+ attrs[j++] = dev_str;
+ }
+ } while (++i < ct);
+
+ /* Save the event attribute */
+ pmu->attr_groups[IMC_EVENT_ATTR] = attr_group;
+
+ kfree(pmu->events);
+ return 0;
+}
+
+/* get_nest_pmu_ref: Return the imc_pmu_ref struct for the given node */
+static struct imc_pmu_ref *get_nest_pmu_ref(int cpu)
+{
+ return per_cpu(local_nest_imc_refc, cpu);
+}
+
+static void nest_change_cpu_context(int old_cpu, int new_cpu)
+{
+ struct imc_pmu **pn = per_nest_pmu_arr;
+ int i;
+
+ if (old_cpu < 0 || new_cpu < 0)
+ return;
+
+ for (i = 0; *pn && i < IMC_MAX_PMUS; i++, pn++)
+ perf_pmu_migrate_context(&(*pn)->pmu, old_cpu, new_cpu);
+}
+
+static int ppc_nest_imc_cpu_offline(unsigned int cpu)
+{
+ int nid, target = -1;
+ const struct cpumask *l_cpumask;
+ struct imc_pmu_ref *ref;
+
+ /*
+ * Check in the designated list for this cpu. Dont bother
+ * if not one of them.
+ */
+ if (!cpumask_test_and_clear_cpu(cpu, &nest_imc_cpumask))
+ return 0;
+
+ /*
+ * Now that this cpu is one of the designated,
+ * find a next cpu a) which is online and b) in same chip.
+ */
+ nid = cpu_to_node(cpu);
+ l_cpumask = cpumask_of_node(nid);
+ target = cpumask_any_but(l_cpumask, cpu);
+
+ /*
+ * Update the cpumask with the target cpu and
+ * migrate the context if needed
+ */
+ if (target >= 0 && target < nr_cpu_ids) {
+ cpumask_set_cpu(target, &nest_imc_cpumask);
+ nest_change_cpu_context(cpu, target);
+ } else {
+ opal_imc_counters_stop(OPAL_IMC_COUNTERS_NEST,
+ get_hard_smp_processor_id(cpu));
+ /*
+ * If this is the last cpu in this chip then, skip the reference
+ * count mutex lock and make the reference count on this chip zero.
+ */
+ ref = get_nest_pmu_ref(cpu);
+ if (!ref)
+ return -EINVAL;
+
+ ref->refc = 0;
+ }
+ return 0;
+}
+
+static int ppc_nest_imc_cpu_online(unsigned int cpu)
+{
+ const struct cpumask *l_cpumask;
+ static struct cpumask tmp_mask;
+ int res;
+
+ /* Get the cpumask of this node */
+ l_cpumask = cpumask_of_node(cpu_to_node(cpu));
+
+ /*
+ * If this is not the first online CPU on this node, then
+ * just return.
+ */
+ if (cpumask_and(&tmp_mask, l_cpumask, &nest_imc_cpumask))
+ return 0;
+
+ /*
+ * If this is the first online cpu on this node
+ * disable the nest counters by making an OPAL call.
+ */
+ res = opal_imc_counters_stop(OPAL_IMC_COUNTERS_NEST,
+ get_hard_smp_processor_id(cpu));
+ if (res)
+ return res;
+
+ /* Make this CPU the designated target for counter collection */
+ cpumask_set_cpu(cpu, &nest_imc_cpumask);
+ return 0;
+}
+
+static int nest_pmu_cpumask_init(void)
+{
+ return cpuhp_setup_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
+ "perf/powerpc/imc:online",
+ ppc_nest_imc_cpu_online,
+ ppc_nest_imc_cpu_offline);
+}
+
+static void nest_imc_counters_release(struct perf_event *event)
+{
+ int rc, node_id;
+ struct imc_pmu_ref *ref;
+
+ if (event->cpu < 0)
+ return;
+
+ node_id = cpu_to_node(event->cpu);
+
+ /*
+ * See if we need to disable the nest PMU.
+ * 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
+ * enable or disable the nest counters.
+ */
+ ref = get_nest_pmu_ref(event->cpu);
+ if (!ref)
+ return;
+
+ /* Take the mutex lock for this node and then decrement the reference count */
+ mutex_lock(&ref->lock);
+ ref->refc--;
+ if (ref->refc == 0) {
+ rc = opal_imc_counters_stop(OPAL_IMC_COUNTERS_NEST,
+ get_hard_smp_processor_id(event->cpu));
+ if (rc) {
+ mutex_unlock(&nest_imc_refc[node_id].lock);
+ pr_err("nest-imc: Unable to stop the counters for core %d\n", node_id);
+ return;
+ }
+ } else if (ref->refc < 0) {
+ WARN(1, "nest-imc: Invalid event reference count\n");
+ ref->refc = 0;
+ }
+ mutex_unlock(&ref->lock);
+}
+
+static int nest_imc_event_init(struct perf_event *event)
+{
+ int chip_id, rc, node_id;
+ u32 l_config, config = event->attr.config;
+ struct imc_mem_info *pcni;
+ struct imc_pmu *pmu;
+ struct imc_pmu_ref *ref;
+ bool flag = false;
+
+ if (event->attr.type != event->pmu->type)
+ return -ENOENT;
+
+ /* Sampling not supported */
+ if (event->hw.sample_period)
+ return -EINVAL;
+
+ /* unsupported modes and filters */
+ if (event->attr.exclude_user ||
+ event->attr.exclude_kernel ||
+ event->attr.exclude_hv ||
+ event->attr.exclude_idle ||
+ event->attr.exclude_host ||
+ event->attr.exclude_guest)
+ return -EINVAL;
+
+ if (event->cpu < 0)
+ return -EINVAL;
+
+ pmu = imc_event_to_pmu(event);
+
+ /* Sanity check for config (event offset) */
+ if ((config & IMC_EVENT_OFFSET_MASK) > pmu->counter_mem_size)
+ return -EINVAL;
+
+ /*
+ * Nest HW counter memory resides in a per-chip reserve-memory (HOMER).
+ * Get the base memory addresss for this cpu.
+ */
+ chip_id = topology_physical_package_id(event->cpu);
+ pcni = pmu->mem_info;
+ do {
+ if (pcni->id == chip_id) {
+ flag = true;
+ break;
+ }
+ pcni++;
+ } while (pcni);
+
+ if (!flag)
+ return -ENODEV;
+
+ /*
+ * Add the event offset to the base address.
+ */
+ l_config = config & IMC_EVENT_OFFSET_MASK;
+ event->hw.event_base = (u64)pcni->vbase + l_config;
+ node_id = cpu_to_node(event->cpu);
+
+ /*
+ * Get the imc_pmu_ref struct for this node.
+ * Take the mutex lock and then increment the count of nest pmu events
+ * inited.
+ */
+ ref = get_nest_pmu_ref(event->cpu);
+ if (!ref)
+ return -EINVAL;
+
+ mutex_lock(&ref->lock);
+ if (ref->refc == 0) {
+ rc = opal_imc_counters_start(OPAL_IMC_COUNTERS_NEST,
+ get_hard_smp_processor_id(event->cpu));
+ if (rc) {
+ mutex_unlock(&nest_imc_refc[node_id].lock);
+ pr_err("nest-imc: Unable to start the counters for node %d\n",
+ node_id);
+ return rc;
+ }
+ }
+ ++ref->refc;
+ mutex_unlock(&ref->lock);
+
+ event->destroy = nest_imc_counters_release;
+ return 0;
+}
+
+static u64 * get_event_base_addr(struct perf_event *event)
+{
+ /*
+ * Subsequent patch will add code to detect caller imc pmu
+ * and return accordingly.
+ */
+ return (u64 *)event->hw.event_base;
+}
+
+static u64 imc_read_counter(struct perf_event *event)
+{
+ u64 *addr, data;
+
+ /*
+ * In-Memory Collection (IMC) counters are free flowing counters.
+ * So we take a snapshot of the counter value on enable and save it
+ * to calculate the delta at later stage to present the event counter
+ * value.
+ */
+ addr = get_event_base_addr(event);
+ data = be64_to_cpu(READ_ONCE(*addr));
+ local64_set(&event->hw.prev_count, data);
+
+ return data;
+}
+
+static void imc_event_update(struct perf_event *event)
+{
+ u64 counter_prev, counter_new, final_count;
+
+ counter_prev = local64_read(&event->hw.prev_count);
+ counter_new = imc_read_counter(event);
+ final_count = counter_new - counter_prev;
+
+ /* Update the delta to the event count */
+ local64_add(final_count, &event->count);
+}
+
+static void imc_event_start(struct perf_event *event, int flags)
+{
+ /*
+ * In Memory Counters are free flowing counters. HW or the microcode
+ * keeps adding to the counter offset in memory. To get event
+ * counter value, we snapshot the value here and we calculate
+ * delta at later point.
+ */
+ imc_read_counter(event);
+}
+
+static void imc_event_stop(struct perf_event *event, int flags)
+{
+ /*
+ * Take a snapshot and calculate the delta and update
+ * the event counter values.
+ */
+ imc_event_update(event);
+}
+
+static int imc_event_add(struct perf_event *event, int flags)
+{
+ if (flags & PERF_EF_START)
+ imc_event_start(event, flags);
+
+ return 0;
+}
+
+/* update_pmu_ops : Populate the appropriate operations for "pmu" */
+static int update_pmu_ops(struct imc_pmu *pmu)
+{
+ pmu->pmu.task_ctx_nr = perf_invalid_context;
+ pmu->pmu.add = imc_event_add;
+ pmu->pmu.del = imc_event_stop;
+ pmu->pmu.start = imc_event_start;
+ pmu->pmu.stop = imc_event_stop;
+ pmu->pmu.read = imc_event_update;
+ pmu->pmu.attr_groups = pmu->attr_groups;
+ pmu->attr_groups[IMC_FORMAT_ATTR] = &imc_format_group;
+
+ /* Subsequenct patch will add more pmu types here */
+ switch (pmu->domain) {
+ case IMC_DOMAIN_NEST:
+ pmu->pmu.event_init = nest_imc_event_init;
+ pmu->attr_groups[IMC_CPUMASK_ATTR] = &imc_pmu_cpumask_attr_group;
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/* init_nest_pmu_ref: Initialize the imc_pmu_ref struct for all the nodes */
+static int init_nest_pmu_ref(void)
+{
+ int nid, i, cpu;
+
+ nest_imc_refc = kcalloc(num_possible_nodes(), sizeof(*nest_imc_refc),
+ GFP_KERNEL);
+
+ if (!nest_imc_refc)
+ return -ENOMEM;
+
+ i = 0;
+ for_each_node(nid) {
+ /*
+ * Mutex lock to avoid races while tracking the number of
+ * sessions using the chip's nest pmu units.
+ */
+ mutex_init(&nest_imc_refc[i].lock);
+
+ /*
+ * Loop to init the "id" with the node_id. Variable "i" initialized to
+ * 0 and will be used as index to the array. "i" will not go off the
+ * end of the array since the "for_each_node" loops for "N_POSSIBLE"
+ * nodes only.
+ */
+ nest_imc_refc[i++].id = nid;
+ }
+
+ /*
+ * Loop to init the per_cpu "local_nest_imc_refc" with the proper
+ * "nest_imc_refc" index. This makes get_nest_pmu_ref() alot simple.
+ */
+ for_each_possible_cpu(cpu) {
+ nid = cpu_to_node(cpu);
+ for_each_online_node(i) {
+ if (nest_imc_refc[i].id == nid) {
+ per_cpu(local_nest_imc_refc, cpu) = &nest_imc_refc[i];
+ break;
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+ * Common function to unregister cpu hotplug callback and
+ * free the memory.
+ * TODO: Need to handle pmu unregistering, which will be
+ * done in followup series.
+ */
+static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
+{
+ if (pmu_ptr->domain == IMC_DOMAIN_NEST) {
+ mutex_unlock(&nest_init_lock);
+ if (nest_pmus == 1) {
+ cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
+ kfree(nest_imc_refc);
+ }
+
+ if (nest_pmus > 0)
+ nest_pmus--;
+ mutex_unlock(&nest_init_lock);
+ }
+
+ /* Only free the attr_groups which are dynamically allocated */
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs);
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]);
+ kfree(pmu_ptr);
+ return;
+}
+
+
+/*
+ * imc_mem_init : Function to support memory allocation for core imc.
+ */
+static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent,
+ int pmu_index)
+{
+ const char *s;
+
+ if (of_property_read_string(parent, "name", &s))
+ return -ENODEV;
+
+ /* Subsequenct patch will add more pmu types here */
+ switch (pmu_ptr->domain) {
+ case IMC_DOMAIN_NEST:
+ /* Update the pmu name */
+ pmu_ptr->pmu.name = kasprintf(GFP_KERNEL, "%s%s_imc", "nest_", s);
+ if (!pmu_ptr->pmu.name)
+ return -ENOMEM;
+
+ /* Needed for hotplug/migration */
+ per_nest_pmu_arr[pmu_index] = pmu_ptr;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * init_imc_pmu : Setup and register the IMC pmu device.
+ *
+ * @parent: Device tree unit node
+ * @pmu_ptr: memory allocated for this pmu
+ * @pmu_idx: Count of nest pmc registered
+ *
+ * init_imc_pmu() setup pmu cpumask and registers for a cpu hotplug callback.
+ * Handles failure cases and accordingly frees memory.
+ */
+int init_imc_pmu(struct device_node *parent, struct imc_pmu *pmu_ptr, int pmu_idx)
+{
+ int ret;
+
+ ret = imc_mem_init(pmu_ptr, parent, pmu_idx);
+ if (ret)
+ goto err_free;
+
+ /* Subsequenct patch will add more pmu types here */
+ switch (pmu_ptr->domain) {
+ case IMC_DOMAIN_NEST:
+ /*
+ * Nest imc pmu need only one cpu per chip, we initialize the
+ * cpumask for the first nest imc pmu and use the same for the
+ * rest. To handle the cpuhotplug callback unregister, we track
+ * the number of nest pmus in "nest_pmus".
+ */
+ mutex_lock(&nest_init_lock);
+ if (nest_pmus == 0) {
+ ret = init_nest_pmu_ref();
+ if (ret) {
+ mutex_unlock(&nest_init_lock);
+ goto err_free;
+ }
+ /* Register for cpu hotplug notification. */
+ ret = nest_pmu_cpumask_init();
+ if (ret) {
+ mutex_unlock(&nest_init_lock);
+ goto err_free;
+ }
+ }
+ nest_pmus++;
+ mutex_unlock(&nest_init_lock);
+ break;
+ default:
+ return -1; /* Unknown domain */
+ }
+
+ ret = update_events_in_group(parent, pmu_ptr);
+ if (ret)
+ goto err_free;
+
+ ret = update_pmu_ops(pmu_ptr);
+ if (ret)
+ goto err_free;
+
+ ret = perf_pmu_register(&pmu_ptr->pmu, pmu_ptr->pmu.name, -1);
+ if (ret)
+ goto err_free;
+
+ pr_info("%s performance monitor hardware support registered\n",
+ pmu_ptr->pmu.name);
+
+ return 0;
+
+err_free:
+ imc_common_cpuhp_mem_free(pmu_ptr);
+ return ret;
+}
projects / users / willy / xarray.git / commitdiff