summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/perf_cpum_cf.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/kernel/perf_cpum_cf.c')
-rw-r--r--arch/s390/kernel/perf_cpum_cf.c580
1 files changed, 580 insertions, 0 deletions
diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
new file mode 100644
index 000000000..dddb32e53
--- /dev/null
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -0,0 +1,580 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Performance event support for s390x - CPU-measurement Counter Facility
+ *
+ * Copyright IBM Corp. 2012, 2019
+ * Author(s): Hendrik Brueckner <brueckner@linux.ibm.com>
+ */
+#define KMSG_COMPONENT "cpum_cf"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <asm/cpu_mcf.h>
+
+static enum cpumf_ctr_set get_counter_set(u64 event)
+{
+ int set = CPUMF_CTR_SET_MAX;
+
+ if (event < 32)
+ set = CPUMF_CTR_SET_BASIC;
+ else if (event < 64)
+ set = CPUMF_CTR_SET_USER;
+ else if (event < 128)
+ set = CPUMF_CTR_SET_CRYPTO;
+ else if (event < 288)
+ set = CPUMF_CTR_SET_EXT;
+ else if (event >= 448 && event < 496)
+ set = CPUMF_CTR_SET_MT_DIAG;
+
+ return set;
+}
+
+static int validate_ctr_version(const struct hw_perf_event *hwc)
+{
+ struct cpu_cf_events *cpuhw;
+ int err = 0;
+ u16 mtdiag_ctl;
+
+ cpuhw = &get_cpu_var(cpu_cf_events);
+
+ /* check required version for counter sets */
+ switch (hwc->config_base) {
+ case CPUMF_CTR_SET_BASIC:
+ case CPUMF_CTR_SET_USER:
+ if (cpuhw->info.cfvn < 1)
+ err = -EOPNOTSUPP;
+ break;
+ case CPUMF_CTR_SET_CRYPTO:
+ if ((cpuhw->info.csvn >= 1 && cpuhw->info.csvn <= 5 &&
+ hwc->config > 79) ||
+ (cpuhw->info.csvn >= 6 && hwc->config > 83))
+ err = -EOPNOTSUPP;
+ break;
+ case CPUMF_CTR_SET_EXT:
+ if (cpuhw->info.csvn < 1)
+ err = -EOPNOTSUPP;
+ if ((cpuhw->info.csvn == 1 && hwc->config > 159) ||
+ (cpuhw->info.csvn == 2 && hwc->config > 175) ||
+ (cpuhw->info.csvn >= 3 && cpuhw->info.csvn <= 5
+ && hwc->config > 255) ||
+ (cpuhw->info.csvn >= 6 && hwc->config > 287))
+ err = -EOPNOTSUPP;
+ break;
+ case CPUMF_CTR_SET_MT_DIAG:
+ if (cpuhw->info.csvn <= 3)
+ err = -EOPNOTSUPP;
+ /*
+ * MT-diagnostic counters are read-only. The counter set
+ * is automatically enabled and activated on all CPUs with
+ * multithreading (SMT). Deactivation of multithreading
+ * also disables the counter set. State changes are ignored
+ * by lcctl(). Because Linux controls SMT enablement through
+ * a kernel parameter only, the counter set is either disabled
+ * or enabled and active.
+ *
+ * Thus, the counters can only be used if SMT is on and the
+ * counter set is enabled and active.
+ */
+ mtdiag_ctl = cpumf_ctr_ctl[CPUMF_CTR_SET_MT_DIAG];
+ if (!((cpuhw->info.auth_ctl & mtdiag_ctl) &&
+ (cpuhw->info.enable_ctl & mtdiag_ctl) &&
+ (cpuhw->info.act_ctl & mtdiag_ctl)))
+ err = -EOPNOTSUPP;
+ break;
+ }
+
+ put_cpu_var(cpu_cf_events);
+ return err;
+}
+
+static int validate_ctr_auth(const struct hw_perf_event *hwc)
+{
+ struct cpu_cf_events *cpuhw;
+ u64 ctrs_state;
+ int err = 0;
+
+ cpuhw = &get_cpu_var(cpu_cf_events);
+
+ /* Check authorization for cpu counter sets.
+ * If the particular CPU counter set is not authorized,
+ * return with -ENOENT in order to fall back to other
+ * PMUs that might suffice the event request.
+ */
+ ctrs_state = cpumf_ctr_ctl[hwc->config_base];
+ if (!(ctrs_state & cpuhw->info.auth_ctl))
+ err = -ENOENT;
+
+ put_cpu_var(cpu_cf_events);
+ return err;
+}
+
+/*
+ * Change the CPUMF state to active.
+ * Enable and activate the CPU-counter sets according
+ * to the per-cpu control state.
+ */
+static void cpumf_pmu_enable(struct pmu *pmu)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+ int err;
+
+ if (cpuhw->flags & PMU_F_ENABLED)
+ return;
+
+ err = lcctl(cpuhw->state);
+ if (err) {
+ pr_err("Enabling the performance measuring unit "
+ "failed with rc=%x\n", err);
+ return;
+ }
+
+ cpuhw->flags |= PMU_F_ENABLED;
+}
+
+/*
+ * Change the CPUMF state to inactive.
+ * Disable and enable (inactive) the CPU-counter sets according
+ * to the per-cpu control state.
+ */
+static void cpumf_pmu_disable(struct pmu *pmu)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+ int err;
+ u64 inactive;
+
+ if (!(cpuhw->flags & PMU_F_ENABLED))
+ return;
+
+ inactive = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
+ err = lcctl(inactive);
+ if (err) {
+ pr_err("Disabling the performance measuring unit "
+ "failed with rc=%x\n", err);
+ return;
+ }
+
+ cpuhw->flags &= ~PMU_F_ENABLED;
+}
+
+
+/* Number of perf events counting hardware events */
+static atomic_t num_events = ATOMIC_INIT(0);
+/* Used to avoid races in calling reserve/release_cpumf_hardware */
+static DEFINE_MUTEX(pmc_reserve_mutex);
+
+/* Release the PMU if event is the last perf event */
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+ if (!atomic_add_unless(&num_events, -1, 1)) {
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_dec_return(&num_events) == 0)
+ __kernel_cpumcf_end();
+ mutex_unlock(&pmc_reserve_mutex);
+ }
+}
+
+/* CPUMF <-> perf event mappings for kernel+userspace (basic set) */
+static const int cpumf_generic_events_basic[] = {
+ [PERF_COUNT_HW_CPU_CYCLES] = 0,
+ [PERF_COUNT_HW_INSTRUCTIONS] = 1,
+ [PERF_COUNT_HW_CACHE_REFERENCES] = -1,
+ [PERF_COUNT_HW_CACHE_MISSES] = -1,
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1,
+ [PERF_COUNT_HW_BRANCH_MISSES] = -1,
+ [PERF_COUNT_HW_BUS_CYCLES] = -1,
+};
+/* CPUMF <-> perf event mappings for userspace (problem-state set) */
+static const int cpumf_generic_events_user[] = {
+ [PERF_COUNT_HW_CPU_CYCLES] = 32,
+ [PERF_COUNT_HW_INSTRUCTIONS] = 33,
+ [PERF_COUNT_HW_CACHE_REFERENCES] = -1,
+ [PERF_COUNT_HW_CACHE_MISSES] = -1,
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1,
+ [PERF_COUNT_HW_BRANCH_MISSES] = -1,
+ [PERF_COUNT_HW_BUS_CYCLES] = -1,
+};
+
+static int __hw_perf_event_init(struct perf_event *event, unsigned int type)
+{
+ struct perf_event_attr *attr = &event->attr;
+ struct hw_perf_event *hwc = &event->hw;
+ enum cpumf_ctr_set set;
+ int err = 0;
+ u64 ev;
+
+ switch (type) {
+ case PERF_TYPE_RAW:
+ /* Raw events are used to access counters directly,
+ * hence do not permit excludes */
+ if (attr->exclude_kernel || attr->exclude_user ||
+ attr->exclude_hv)
+ return -EOPNOTSUPP;
+ ev = attr->config;
+ break;
+
+ case PERF_TYPE_HARDWARE:
+ if (is_sampling_event(event)) /* No sampling support */
+ return -ENOENT;
+ ev = attr->config;
+ /* Count user space (problem-state) only */
+ if (!attr->exclude_user && attr->exclude_kernel) {
+ if (ev >= ARRAY_SIZE(cpumf_generic_events_user))
+ return -EOPNOTSUPP;
+ ev = cpumf_generic_events_user[ev];
+
+ /* No support for kernel space counters only */
+ } else if (!attr->exclude_kernel && attr->exclude_user) {
+ return -EOPNOTSUPP;
+
+ /* Count user and kernel space */
+ } else {
+ if (ev >= ARRAY_SIZE(cpumf_generic_events_basic))
+ return -EOPNOTSUPP;
+ ev = cpumf_generic_events_basic[ev];
+ }
+ break;
+
+ default:
+ return -ENOENT;
+ }
+
+ if (ev == -1)
+ return -ENOENT;
+
+ if (ev > PERF_CPUM_CF_MAX_CTR)
+ return -ENOENT;
+
+ /* Obtain the counter set to which the specified counter belongs */
+ set = get_counter_set(ev);
+ switch (set) {
+ case CPUMF_CTR_SET_BASIC:
+ case CPUMF_CTR_SET_USER:
+ case CPUMF_CTR_SET_CRYPTO:
+ case CPUMF_CTR_SET_EXT:
+ case CPUMF_CTR_SET_MT_DIAG:
+ /*
+ * Use the hardware perf event structure to store the
+ * counter number in the 'config' member and the counter
+ * set number in the 'config_base'. The counter set number
+ * is then later used to enable/disable the counter(s).
+ */
+ hwc->config = ev;
+ hwc->config_base = set;
+ break;
+ case CPUMF_CTR_SET_MAX:
+ /* The counter could not be associated to a counter set */
+ return -EINVAL;
+ };
+
+ /* Initialize for using the CPU-measurement counter facility */
+ if (!atomic_inc_not_zero(&num_events)) {
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_read(&num_events) == 0 && __kernel_cpumcf_begin())
+ err = -EBUSY;
+ else
+ atomic_inc(&num_events);
+ mutex_unlock(&pmc_reserve_mutex);
+ }
+ if (err)
+ return err;
+ event->destroy = hw_perf_event_destroy;
+
+ /* Finally, validate version and authorization of the counter set */
+ err = validate_ctr_auth(hwc);
+ if (!err)
+ err = validate_ctr_version(hwc);
+
+ return err;
+}
+
+/* Events CPU_CYLCES and INSTRUCTIONS can be submitted with two different
+ * attribute::type values:
+ * - PERF_TYPE_HARDWARE:
+ * - pmu->type:
+ * Handle both type of invocations identical. They address the same hardware.
+ * The result is different when event modifiers exclude_kernel and/or
+ * exclude_user are also set.
+ */
+static int cpumf_pmu_event_type(struct perf_event *event)
+{
+ u64 ev = event->attr.config;
+
+ if (cpumf_generic_events_basic[PERF_COUNT_HW_CPU_CYCLES] == ev ||
+ cpumf_generic_events_basic[PERF_COUNT_HW_INSTRUCTIONS] == ev ||
+ cpumf_generic_events_user[PERF_COUNT_HW_CPU_CYCLES] == ev ||
+ cpumf_generic_events_user[PERF_COUNT_HW_INSTRUCTIONS] == ev)
+ return PERF_TYPE_HARDWARE;
+ return PERF_TYPE_RAW;
+}
+
+static int cpumf_pmu_event_init(struct perf_event *event)
+{
+ unsigned int type = event->attr.type;
+ int err;
+
+ if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_RAW)
+ err = __hw_perf_event_init(event, type);
+ else if (event->pmu->type == type)
+ /* Registered as unknown PMU */
+ err = __hw_perf_event_init(event, cpumf_pmu_event_type(event));
+ else
+ return -ENOENT;
+
+ if (unlikely(err) && event->destroy)
+ event->destroy(event);
+
+ return err;
+}
+
+static int hw_perf_event_reset(struct perf_event *event)
+{
+ u64 prev, new;
+ int err;
+
+ do {
+ prev = local64_read(&event->hw.prev_count);
+ err = ecctr(event->hw.config, &new);
+ if (err) {
+ if (err != 3)
+ break;
+ /* The counter is not (yet) available. This
+ * might happen if the counter set to which
+ * this counter belongs is in the disabled
+ * state.
+ */
+ new = 0;
+ }
+ } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
+
+ return err;
+}
+
+static void hw_perf_event_update(struct perf_event *event)
+{
+ u64 prev, new, delta;
+ int err;
+
+ do {
+ prev = local64_read(&event->hw.prev_count);
+ err = ecctr(event->hw.config, &new);
+ if (err)
+ return;
+ } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
+
+ delta = (prev <= new) ? new - prev
+ : (-1ULL - prev) + new + 1; /* overflow */
+ local64_add(delta, &event->count);
+}
+
+static void cpumf_pmu_read(struct perf_event *event)
+{
+ if (event->hw.state & PERF_HES_STOPPED)
+ return;
+
+ hw_perf_event_update(event);
+}
+
+static void cpumf_pmu_start(struct perf_event *event, int flags)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
+ return;
+
+ if (WARN_ON_ONCE(hwc->config == -1))
+ return;
+
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+
+ hwc->state = 0;
+
+ /* (Re-)enable and activate the counter set */
+ ctr_set_enable(&cpuhw->state, hwc->config_base);
+ ctr_set_start(&cpuhw->state, hwc->config_base);
+
+ /* The counter set to which this counter belongs can be already active.
+ * Because all counters in a set are active, the event->hw.prev_count
+ * needs to be synchronized. At this point, the counter set can be in
+ * the inactive or disabled state.
+ */
+ hw_perf_event_reset(event);
+
+ /* increment refcount for this counter set */
+ atomic_inc(&cpuhw->ctr_set[hwc->config_base]);
+}
+
+static void cpumf_pmu_stop(struct perf_event *event, int flags)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (!(hwc->state & PERF_HES_STOPPED)) {
+ /* Decrement reference count for this counter set and if this
+ * is the last used counter in the set, clear activation
+ * control and set the counter set state to inactive.
+ */
+ if (!atomic_dec_return(&cpuhw->ctr_set[hwc->config_base]))
+ ctr_set_stop(&cpuhw->state, hwc->config_base);
+ event->hw.state |= PERF_HES_STOPPED;
+ }
+
+ if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+ hw_perf_event_update(event);
+ event->hw.state |= PERF_HES_UPTODATE;
+ }
+}
+
+static int cpumf_pmu_add(struct perf_event *event, int flags)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+
+ /* Check authorization for the counter set to which this
+ * counter belongs.
+ * For group events transaction, the authorization check is
+ * done in cpumf_pmu_commit_txn().
+ */
+ if (!(cpuhw->txn_flags & PERF_PMU_TXN_ADD))
+ if (validate_ctr_auth(&event->hw))
+ return -ENOENT;
+
+ ctr_set_enable(&cpuhw->state, event->hw.config_base);
+ event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+ if (flags & PERF_EF_START)
+ cpumf_pmu_start(event, PERF_EF_RELOAD);
+
+ perf_event_update_userpage(event);
+
+ return 0;
+}
+
+static void cpumf_pmu_del(struct perf_event *event, int flags)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+
+ cpumf_pmu_stop(event, PERF_EF_UPDATE);
+
+ /* Check if any counter in the counter set is still used. If not used,
+ * change the counter set to the disabled state. This also clears the
+ * content of all counters in the set.
+ *
+ * When a new perf event has been added but not yet started, this can
+ * clear enable control and resets all counters in a set. Therefore,
+ * cpumf_pmu_start() always has to reenable a counter set.
+ */
+ if (!atomic_read(&cpuhw->ctr_set[event->hw.config_base]))
+ ctr_set_disable(&cpuhw->state, event->hw.config_base);
+
+ perf_event_update_userpage(event);
+}
+
+/*
+ * Start group events scheduling transaction.
+ * Set flags to perform a single test at commit time.
+ *
+ * We only support PERF_PMU_TXN_ADD transactions. Save the
+ * transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD
+ * transactions.
+ */
+static void cpumf_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+
+ WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */
+
+ cpuhw->txn_flags = txn_flags;
+ if (txn_flags & ~PERF_PMU_TXN_ADD)
+ return;
+
+ perf_pmu_disable(pmu);
+ cpuhw->tx_state = cpuhw->state;
+}
+
+/*
+ * Stop and cancel a group events scheduling tranctions.
+ * Assumes cpumf_pmu_del() is called for each successful added
+ * cpumf_pmu_add() during the transaction.
+ */
+static void cpumf_pmu_cancel_txn(struct pmu *pmu)
+{
+ unsigned int txn_flags;
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+
+ WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
+
+ txn_flags = cpuhw->txn_flags;
+ cpuhw->txn_flags = 0;
+ if (txn_flags & ~PERF_PMU_TXN_ADD)
+ return;
+
+ WARN_ON(cpuhw->tx_state != cpuhw->state);
+
+ perf_pmu_enable(pmu);
+}
+
+/*
+ * Commit the group events scheduling transaction. On success, the
+ * transaction is closed. On error, the transaction is kept open
+ * until cpumf_pmu_cancel_txn() is called.
+ */
+static int cpumf_pmu_commit_txn(struct pmu *pmu)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+ u64 state;
+
+ WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */
+
+ if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) {
+ cpuhw->txn_flags = 0;
+ return 0;
+ }
+
+ /* check if the updated state can be scheduled */
+ state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1);
+ state >>= CPUMF_LCCTL_ENABLE_SHIFT;
+ if ((state & cpuhw->info.auth_ctl) != state)
+ return -ENOENT;
+
+ cpuhw->txn_flags = 0;
+ perf_pmu_enable(pmu);
+ return 0;
+}
+
+/* Performance monitoring unit for s390x */
+static struct pmu cpumf_pmu = {
+ .task_ctx_nr = perf_sw_context,
+ .capabilities = PERF_PMU_CAP_NO_INTERRUPT,
+ .pmu_enable = cpumf_pmu_enable,
+ .pmu_disable = cpumf_pmu_disable,
+ .event_init = cpumf_pmu_event_init,
+ .add = cpumf_pmu_add,
+ .del = cpumf_pmu_del,
+ .start = cpumf_pmu_start,
+ .stop = cpumf_pmu_stop,
+ .read = cpumf_pmu_read,
+ .start_txn = cpumf_pmu_start_txn,
+ .commit_txn = cpumf_pmu_commit_txn,
+ .cancel_txn = cpumf_pmu_cancel_txn,
+};
+
+static int __init cpumf_pmu_init(void)
+{
+ int rc;
+
+ if (!kernel_cpumcf_avail())
+ return -ENODEV;
+
+ cpumf_pmu.attr_groups = cpumf_cf_event_group();
+ rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", -1);
+ if (rc)
+ pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc);
+ return rc;
+}
+subsys_initcall(cpumf_pmu_init);