--- /dev/null
+/*
+ * Intel Cache Quality-of-Service Monitoring (CQM) support.
+ *
+ * Based very, very heavily on work by Peter Zijlstra.
+ */
+
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+#include <asm/cpu_device_id.h>
+#include "perf_event.h"
+
+#define MSR_IA32_PQR_ASSOC 0x0c8f
+#define MSR_IA32_QM_CTR 0x0c8e
+#define MSR_IA32_QM_EVTSEL 0x0c8d
+
+static unsigned int cqm_max_rmid = -1;
+static unsigned int cqm_l3_scale; /* supposedly cacheline size */
+
+struct intel_cqm_state {
+ raw_spinlock_t lock;
+ int rmid;
+ int cnt;
+};
+
+static DEFINE_PER_CPU(struct intel_cqm_state, cqm_state);
+
+/*
+ * Protects cache_cgroups.
+ */
+static DEFINE_MUTEX(cache_mutex);
+
+/*
+ * Groups of events that have the same target(s), one RMID per group.
+ */
+static LIST_HEAD(cache_groups);
+
+/*
+ * Mask of CPUs for reading CQM values. We only need one per-socket.
+ */
+static cpumask_t cqm_cpumask;
+
+#define RMID_VAL_ERROR (1ULL << 63)
+#define RMID_VAL_UNAVAIL (1ULL << 62)
+
+#define QOS_L3_OCCUP_EVENT_ID (1 << 0)
+
+#define QOS_EVENT_MASK QOS_L3_OCCUP_EVENT_ID
+
+static u64 __rmid_read(unsigned long rmid)
+{
+ u64 val;
+
+ /*
+ * Ignore the SDM, this thing is _NOTHING_ like a regular perfcnt,
+ * it just says that to increase confusion.
+ */
+ wrmsr(MSR_IA32_QM_EVTSEL, QOS_L3_OCCUP_EVENT_ID, rmid);
+ rdmsrl(MSR_IA32_QM_CTR, val);
+
+ /*
+ * Aside from the ERROR and UNAVAIL bits, assume this thing returns
+ * the number of cachelines tagged with @rmid.
+ */
+ return val;
+}
+
+static unsigned long *cqm_rmid_bitmap;
+
+/*
+ * Returns < 0 on fail.
+ */
+static int __get_rmid(void)
+{
+ return bitmap_find_free_region(cqm_rmid_bitmap, cqm_max_rmid, 0);
+}
+
+static void __put_rmid(int rmid)
+{
+ bitmap_release_region(cqm_rmid_bitmap, rmid, 0);
+}
+
+static int intel_cqm_setup_rmid_cache(void)
+{
+ cqm_rmid_bitmap = kmalloc(sizeof(long) * BITS_TO_LONGS(cqm_max_rmid), GFP_KERNEL);
+ if (!cqm_rmid_bitmap)
+ return -ENOMEM;
+
+ bitmap_zero(cqm_rmid_bitmap, cqm_max_rmid);
+
+ /*
+ * RMID 0 is special and is always allocated. It's used for all
+ * tasks that are not monitored.
+ */
+ bitmap_allocate_region(cqm_rmid_bitmap, 0, 0);
+
+ return 0;
+}
+
+/*
+ * Determine if @a and @b measure the same set of tasks.
+ */
+static bool __match_event(struct perf_event *a, struct perf_event *b)
+{
+ if ((a->attach_state & PERF_ATTACH_TASK) !=
+ (b->attach_state & PERF_ATTACH_TASK))
+ return false;
+
+ /* not task */
+
+ return true; /* if not task, we're machine wide */
+}
+
+/*
+ * Determine if @a's tasks intersect with @b's tasks
+ */
+static bool __conflict_event(struct perf_event *a, struct perf_event *b)
+{
+ /*
+ * If one of them is not a task, same story as above with cgroups.
+ */
+ if (!(a->attach_state & PERF_ATTACH_TASK) ||
+ !(b->attach_state & PERF_ATTACH_TASK))
+ return true;
+
+ /*
+ * Must be non-overlapping.
+ */
+ return false;
+}
+
+/*
+ * Find a group and setup RMID.
+ *
+ * If we're part of a group, we use the group's RMID.
+ */
+static int intel_cqm_setup_event(struct perf_event *event,
+ struct perf_event **group)
+{
+ struct perf_event *iter;
+ int rmid;
+
+ list_for_each_entry(iter, &cache_groups, hw.cqm_groups_entry) {
+ if (__match_event(iter, event)) {
+ /* All tasks in a group share an RMID */
+ event->hw.cqm_rmid = iter->hw.cqm_rmid;
+ *group = iter;
+ return 0;
+ }
+
+ if (__conflict_event(iter, event))
+ return -EBUSY;
+ }
+
+ rmid = __get_rmid();
+ if (rmid < 0)
+ return rmid;
+
+ event->hw.cqm_rmid = rmid;
+ return 0;
+}
+
+static void intel_cqm_event_read(struct perf_event *event)
+{
+ unsigned long rmid = event->hw.cqm_rmid;
+ u64 val;
+
+ val = __rmid_read(rmid);
+
+ /*
+ * Ignore this reading on error states and do not update the value.
+ */
+ if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))
+ return;
+
+ local64_set(&event->count, val);
+}
+
+static void intel_cqm_event_start(struct perf_event *event, int mode)
+{
+ struct intel_cqm_state *state = this_cpu_ptr(&cqm_state);
+ unsigned long rmid = event->hw.cqm_rmid;
+ unsigned long flags;
+
+ if (!(event->hw.cqm_state & PERF_HES_STOPPED))
+ return;
+
+ event->hw.cqm_state &= ~PERF_HES_STOPPED;
+
+ raw_spin_lock_irqsave(&state->lock, flags);
+
+ if (state->cnt++)
+ WARN_ON_ONCE(state->rmid != rmid);
+ else
+ WARN_ON_ONCE(state->rmid);
+
+ state->rmid = rmid;
+ wrmsrl(MSR_IA32_PQR_ASSOC, state->rmid);
+
+ raw_spin_unlock_irqrestore(&state->lock, flags);
+}
+
+static void intel_cqm_event_stop(struct perf_event *event, int mode)
+{
+ struct intel_cqm_state *state = this_cpu_ptr(&cqm_state);
+ unsigned long flags;
+
+ if (event->hw.cqm_state & PERF_HES_STOPPED)
+ return;
+
+ event->hw.cqm_state |= PERF_HES_STOPPED;
+
+ raw_spin_lock_irqsave(&state->lock, flags);
+ intel_cqm_event_read(event);
+
+ if (!--state->cnt) {
+ state->rmid = 0;
+ wrmsrl(MSR_IA32_PQR_ASSOC, 0);
+ } else {
+ WARN_ON_ONCE(!state->rmid);
+ }
+
+ raw_spin_unlock_irqrestore(&state->lock, flags);
+}
+
+static int intel_cqm_event_add(struct perf_event *event, int mode)
+{
+ int rmid;
+
+ event->hw.cqm_state = PERF_HES_STOPPED;
+ rmid = event->hw.cqm_rmid;
+ WARN_ON_ONCE(!rmid);
+
+ if (mode & PERF_EF_START)
+ intel_cqm_event_start(event, mode);
+
+ return 0;
+}
+
+static void intel_cqm_event_del(struct perf_event *event, int mode)
+{
+ intel_cqm_event_stop(event, mode);
+}
+
+static void intel_cqm_event_destroy(struct perf_event *event)
+{
+ struct perf_event *group_other = NULL;
+
+ mutex_lock(&cache_mutex);
+
+ /*
+ * If there's another event in this group...
+ */
+ if (!list_empty(&event->hw.cqm_group_entry)) {
+ group_other = list_first_entry(&event->hw.cqm_group_entry,
+ struct perf_event,
+ hw.cqm_group_entry);
+ list_del(&event->hw.cqm_group_entry);
+ }
+
+ /*
+ * And we're the group leader..
+ */
+ if (!list_empty(&event->hw.cqm_groups_entry)) {
+ /*
+ * If there was a group_other, make that leader, otherwise
+ * destroy the group and return the RMID.
+ */
+ if (group_other) {
+ list_replace(&event->hw.cqm_groups_entry,
+ &group_other->hw.cqm_groups_entry);
+ } else {
+ int rmid = event->hw.cqm_rmid;
+
+ __put_rmid(rmid);
+ list_del(&event->hw.cqm_groups_entry);
+ }
+ }
+
+ mutex_unlock(&cache_mutex);
+}
+
+static struct pmu intel_cqm_pmu;
+
+/*
+ * XXX there's a bit of a problem in that we cannot simply do the one
+ * event per node as one would want, since that one event would one get
+ * scheduled on the one cpu. But we want to 'schedule' the RMID on all
+ * CPUs.
+ *
+ * This means we want events for each CPU, however, that generates a lot
+ * of duplicate values out to userspace -- this is not to be helped
+ * unless we want to change the core code in some way. Fore more info,
+ * see intel_cqm_event_read().
+ */
+static int intel_cqm_event_init(struct perf_event *event)
+{
+ struct perf_event *group = NULL;
+ int err;
+
+ if (event->attr.type != intel_cqm_pmu.type)
+ return -ENOENT;
+
+ if (event->attr.config & ~QOS_EVENT_MASK)
+ return -EINVAL;
+
+ if (event->cpu == -1)
+ 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 ||
+ event->attr.sample_period) /* no sampling */
+ return -EINVAL;
+
+ INIT_LIST_HEAD(&event->hw.cqm_group_entry);
+ INIT_LIST_HEAD(&event->hw.cqm_groups_entry);
+
+ event->destroy = intel_cqm_event_destroy;
+
+ mutex_lock(&cache_mutex);
+
+ err = intel_cqm_setup_event(event, &group); /* will also set rmid */
+ if (err)
+ goto out;
+
+ if (group) {
+ list_add_tail(&event->hw.cqm_group_entry,
+ &group->hw.cqm_group_entry);
+ } else {
+ list_add_tail(&event->hw.cqm_groups_entry,
+ &cache_groups);
+ }
+
+out:
+ mutex_unlock(&cache_mutex);
+ return err;
+}
+
+EVENT_ATTR_STR(llc_occupancy, intel_cqm_llc, "event=0x01");
+EVENT_ATTR_STR(llc_occupancy.per-pkg, intel_cqm_llc_pkg, "1");
+EVENT_ATTR_STR(llc_occupancy.unit, intel_cqm_llc_unit, "Bytes");
+EVENT_ATTR_STR(llc_occupancy.scale, intel_cqm_llc_scale, NULL);
+EVENT_ATTR_STR(llc_occupancy.snapshot, intel_cqm_llc_snapshot, "1");
+
+static struct attribute *intel_cqm_events_attr[] = {
+ EVENT_PTR(intel_cqm_llc),
+ EVENT_PTR(intel_cqm_llc_pkg),
+ EVENT_PTR(intel_cqm_llc_unit),
+ EVENT_PTR(intel_cqm_llc_scale),
+ EVENT_PTR(intel_cqm_llc_snapshot),
+ NULL,
+};
+
+static struct attribute_group intel_cqm_events_group = {
+ .name = "events",
+ .attrs = intel_cqm_events_attr,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-7");
+static struct attribute *intel_cqm_formats_attr[] = {
+ &format_attr_event.attr,
+ NULL,
+};
+
+static struct attribute_group intel_cqm_format_group = {
+ .name = "format",
+ .attrs = intel_cqm_formats_attr,
+};
+
+static const struct attribute_group *intel_cqm_attr_groups[] = {
+ &intel_cqm_events_group,
+ &intel_cqm_format_group,
+ NULL,
+};
+
+static struct pmu intel_cqm_pmu = {
+ .attr_groups = intel_cqm_attr_groups,
+ .task_ctx_nr = perf_sw_context,
+ .event_init = intel_cqm_event_init,
+ .add = intel_cqm_event_add,
+ .del = intel_cqm_event_del,
+ .start = intel_cqm_event_start,
+ .stop = intel_cqm_event_stop,
+ .read = intel_cqm_event_read,
+};
+
+static inline void cqm_pick_event_reader(int cpu)
+{
+ int phys_id = topology_physical_package_id(cpu);
+ int i;
+
+ for_each_cpu(i, &cqm_cpumask) {
+ if (phys_id == topology_physical_package_id(i))
+ return; /* already got reader for this socket */
+ }
+
+ cpumask_set_cpu(cpu, &cqm_cpumask);
+}
+
+static void intel_cqm_cpu_prepare(unsigned int cpu)
+{
+ struct intel_cqm_state *state = &per_cpu(cqm_state, cpu);
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+ raw_spin_lock_init(&state->lock);
+ state->rmid = 0;
+ state->cnt = 0;
+
+ WARN_ON(c->x86_cache_max_rmid != cqm_max_rmid);
+ WARN_ON(c->x86_cache_occ_scale != cqm_l3_scale);
+}
+
+static void intel_cqm_cpu_exit(unsigned int cpu)
+{
+ int phys_id = topology_physical_package_id(cpu);
+ int i;
+
+ /*
+ * Is @cpu a designated cqm reader?
+ */
+ if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask))
+ return;
+
+ for_each_online_cpu(i) {
+ if (i == cpu)
+ continue;
+
+ if (phys_id == topology_physical_package_id(i)) {
+ cpumask_set_cpu(i, &cqm_cpumask);
+ break;
+ }
+ }
+}
+
+static int intel_cqm_cpu_notifier(struct notifier_block *nb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_UP_PREPARE:
+ intel_cqm_cpu_prepare(cpu);
+ break;
+ case CPU_DOWN_PREPARE:
+ intel_cqm_cpu_exit(cpu);
+ break;
+ case CPU_STARTING:
+ cqm_pick_event_reader(cpu);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static const struct x86_cpu_id intel_cqm_match[] = {
+ { .vendor = X86_VENDOR_INTEL, .feature = X86_FEATURE_CQM_OCCUP_LLC },
+ {}
+};
+
+static int __init intel_cqm_init(void)
+{
+ char *str, scale[20];
+ int i, cpu, ret;
+
+ if (!x86_match_cpu(intel_cqm_match))
+ return -ENODEV;
+
+ cqm_l3_scale = boot_cpu_data.x86_cache_occ_scale;
+
+ /*
+ * It's possible that not all resources support the same number
+ * of RMIDs. Instead of making scheduling much more complicated
+ * (where we have to match a task's RMID to a cpu that supports
+ * that many RMIDs) just find the minimum RMIDs supported across
+ * all cpus.
+ *
+ * Also, check that the scales match on all cpus.
+ */
+ cpu_notifier_register_begin();
+
+ for_each_online_cpu(cpu) {
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+ if (c->x86_cache_max_rmid < cqm_max_rmid)
+ cqm_max_rmid = c->x86_cache_max_rmid;
+
+ if (c->x86_cache_occ_scale != cqm_l3_scale) {
+ pr_err("Multiple LLC scale values, disabling\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ snprintf(scale, sizeof(scale), "%u", cqm_l3_scale);
+ str = kstrdup(scale, GFP_KERNEL);
+ if (!str) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ event_attr_intel_cqm_llc_scale.event_str = str;
+
+ ret = intel_cqm_setup_rmid_cache();
+ if (ret)
+ goto out;
+
+ for_each_online_cpu(i) {
+ intel_cqm_cpu_prepare(i);
+ cqm_pick_event_reader(i);
+ }
+
+ __perf_cpu_notifier(intel_cqm_cpu_notifier);
+
+ ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1);
+
+ if (ret)
+ pr_err("Intel CQM perf registration failed: %d\n", ret);
+ else
+ pr_info("Intel CQM monitoring enabled\n");
+
+out:
+ cpu_notifier_register_done();
+
+ return ret;
+}
+device_initcall(intel_cqm_init);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff