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);