Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1543 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..28fa80fd6
--- /dev/null
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -0,0 +1,1543 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Performance event support for s390x - CPU-measurement Counter Facility
+ *
+ *  Copyright IBM Corp. 2012, 2022
+ *  Author(s): Hendrik Brueckner <brueckner@linux.ibm.com>
+ *	       Thomas Richter <tmricht@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 <linux/miscdevice.h>
+
+#include <asm/cpu_mcf.h>
+#include <asm/hwctrset.h>
+#include <asm/debug.h>
+
+static unsigned int cfdiag_cpu_speed;	/* CPU speed for CF_DIAG trailer */
+static debug_info_t *cf_dbg;
+
+#define	CF_DIAG_CTRSET_DEF		0xfeef	/* Counter set header mark */
+						/* interval in seconds */
+
+/* Counter sets are stored as data stream in a page sized memory buffer and
+ * exported to user space via raw data attached to the event sample data.
+ * Each counter set starts with an eight byte header consisting of:
+ * - a two byte eye catcher (0xfeef)
+ * - a one byte counter set number
+ * - a two byte counter set size (indicates the number of counters in this set)
+ * - a three byte reserved value (must be zero) to make the header the same
+ *   size as a counter value.
+ * All counter values are eight byte in size.
+ *
+ * All counter sets are followed by a 64 byte trailer.
+ * The trailer consists of a:
+ * - flag field indicating valid fields when corresponding bit set
+ * - the counter facility first and second version number
+ * - the CPU speed if nonzero
+ * - the time stamp the counter sets have been collected
+ * - the time of day (TOD) base value
+ * - the machine type.
+ *
+ * The counter sets are saved when the process is prepared to be executed on a
+ * CPU and saved again when the process is going to be removed from a CPU.
+ * The difference of both counter sets are calculated and stored in the event
+ * sample data area.
+ */
+struct cf_ctrset_entry {	/* CPU-M CF counter set entry (8 byte) */
+	unsigned int def:16;	/* 0-15  Data Entry Format */
+	unsigned int set:16;	/* 16-31 Counter set identifier */
+	unsigned int ctr:16;	/* 32-47 Number of stored counters */
+	unsigned int res1:16;	/* 48-63 Reserved */
+};
+
+struct cf_trailer_entry {	/* CPU-M CF_DIAG trailer (64 byte) */
+	/* 0 - 7 */
+	union {
+		struct {
+			unsigned int clock_base:1;	/* TOD clock base set */
+			unsigned int speed:1;		/* CPU speed set */
+			/* Measurement alerts */
+			unsigned int mtda:1;	/* Loss of MT ctr. data alert */
+			unsigned int caca:1;	/* Counter auth. change alert */
+			unsigned int lcda:1;	/* Loss of counter data alert */
+		};
+		unsigned long flags;	/* 0-63    All indicators */
+	};
+	/* 8 - 15 */
+	unsigned int cfvn:16;			/* 64-79   Ctr First Version */
+	unsigned int csvn:16;			/* 80-95   Ctr Second Version */
+	unsigned int cpu_speed:32;		/* 96-127  CPU speed */
+	/* 16 - 23 */
+	unsigned long timestamp;		/* 128-191 Timestamp (TOD) */
+	/* 24 - 55 */
+	union {
+		struct {
+			unsigned long progusage1;
+			unsigned long progusage2;
+			unsigned long progusage3;
+			unsigned long tod_base;
+		};
+		unsigned long progusage[4];
+	};
+	/* 56 - 63 */
+	unsigned int mach_type:16;		/* Machine type */
+	unsigned int res1:16;			/* Reserved */
+	unsigned int res2:32;			/* Reserved */
+};
+
+/* Create the trailer data at the end of a page. */
+static void cfdiag_trailer(struct cf_trailer_entry *te)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	struct cpuid cpuid;
+
+	te->cfvn = cpuhw->info.cfvn;		/* Counter version numbers */
+	te->csvn = cpuhw->info.csvn;
+
+	get_cpu_id(&cpuid);			/* Machine type */
+	te->mach_type = cpuid.machine;
+	te->cpu_speed = cfdiag_cpu_speed;
+	if (te->cpu_speed)
+		te->speed = 1;
+	te->clock_base = 1;			/* Save clock base */
+	te->tod_base = tod_clock_base.tod;
+	te->timestamp = get_tod_clock_fast();
+}
+
+/* Read a counter set. The counter set number determines the counter set and
+ * the CPUM-CF first and second version number determine the number of
+ * available counters in each counter set.
+ * Each counter set starts with header containing the counter set number and
+ * the number of eight byte counters.
+ *
+ * The functions returns the number of bytes occupied by this counter set
+ * including the header.
+ * If there is no counter in the counter set, this counter set is useless and
+ * zero is returned on this case.
+ *
+ * Note that the counter sets may not be enabled or active and the stcctm
+ * instruction might return error 3. Depending on error_ok value this is ok,
+ * for example when called from cpumf_pmu_start() call back function.
+ */
+static size_t cfdiag_getctrset(struct cf_ctrset_entry *ctrdata, int ctrset,
+			       size_t room, bool error_ok)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	size_t ctrset_size, need = 0;
+	int rc = 3;				/* Assume write failure */
+
+	ctrdata->def = CF_DIAG_CTRSET_DEF;
+	ctrdata->set = ctrset;
+	ctrdata->res1 = 0;
+	ctrset_size = cpum_cf_ctrset_size(ctrset, &cpuhw->info);
+
+	if (ctrset_size) {			/* Save data */
+		need = ctrset_size * sizeof(u64) + sizeof(*ctrdata);
+		if (need <= room) {
+			rc = ctr_stcctm(ctrset, ctrset_size,
+					(u64 *)(ctrdata + 1));
+		}
+		if (rc != 3 || error_ok)
+			ctrdata->ctr = ctrset_size;
+		else
+			need = 0;
+	}
+
+	debug_sprintf_event(cf_dbg, 3,
+			    "%s ctrset %d ctrset_size %zu cfvn %d csvn %d"
+			    " need %zd rc %d\n", __func__, ctrset, ctrset_size,
+			    cpuhw->info.cfvn, cpuhw->info.csvn, need, rc);
+	return need;
+}
+
+static const u64 cpumf_ctr_ctl[CPUMF_CTR_SET_MAX] = {
+	[CPUMF_CTR_SET_BASIC]	= 0x02,
+	[CPUMF_CTR_SET_USER]	= 0x04,
+	[CPUMF_CTR_SET_CRYPTO]	= 0x08,
+	[CPUMF_CTR_SET_EXT]	= 0x01,
+	[CPUMF_CTR_SET_MT_DIAG] = 0x20,
+};
+
+/* Read out all counter sets and save them in the provided data buffer.
+ * The last 64 byte host an artificial trailer entry.
+ */
+static size_t cfdiag_getctr(void *data, size_t sz, unsigned long auth,
+			    bool error_ok)
+{
+	struct cf_trailer_entry *trailer;
+	size_t offset = 0, done;
+	int i;
+
+	memset(data, 0, sz);
+	sz -= sizeof(*trailer);		/* Always room for trailer */
+	for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i) {
+		struct cf_ctrset_entry *ctrdata = data + offset;
+
+		if (!(auth & cpumf_ctr_ctl[i]))
+			continue;	/* Counter set not authorized */
+
+		done = cfdiag_getctrset(ctrdata, i, sz - offset, error_ok);
+		offset += done;
+	}
+	trailer = data + offset;
+	cfdiag_trailer(trailer);
+	return offset + sizeof(*trailer);
+}
+
+/* Calculate the difference for each counter in a counter set. */
+static void cfdiag_diffctrset(u64 *pstart, u64 *pstop, int counters)
+{
+	for (; --counters >= 0; ++pstart, ++pstop)
+		if (*pstop >= *pstart)
+			*pstop -= *pstart;
+		else
+			*pstop = *pstart - *pstop + 1;
+}
+
+/* Scan the counter sets and calculate the difference of each counter
+ * in each set. The result is the increment of each counter during the
+ * period the counter set has been activated.
+ *
+ * Return true on success.
+ */
+static int cfdiag_diffctr(struct cpu_cf_events *cpuhw, unsigned long auth)
+{
+	struct cf_trailer_entry *trailer_start, *trailer_stop;
+	struct cf_ctrset_entry *ctrstart, *ctrstop;
+	size_t offset = 0;
+
+	auth &= (1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1;
+	do {
+		ctrstart = (struct cf_ctrset_entry *)(cpuhw->start + offset);
+		ctrstop = (struct cf_ctrset_entry *)(cpuhw->stop + offset);
+
+		if (memcmp(ctrstop, ctrstart, sizeof(*ctrstop))) {
+			pr_err_once("cpum_cf_diag counter set compare error "
+				    "in set %i\n", ctrstart->set);
+			return 0;
+		}
+		auth &= ~cpumf_ctr_ctl[ctrstart->set];
+		if (ctrstart->def == CF_DIAG_CTRSET_DEF) {
+			cfdiag_diffctrset((u64 *)(ctrstart + 1),
+					  (u64 *)(ctrstop + 1), ctrstart->ctr);
+			offset += ctrstart->ctr * sizeof(u64) +
+							sizeof(*ctrstart);
+		}
+	} while (ctrstart->def && auth);
+
+	/* Save time_stamp from start of event in stop's trailer */
+	trailer_start = (struct cf_trailer_entry *)(cpuhw->start + offset);
+	trailer_stop = (struct cf_trailer_entry *)(cpuhw->stop + offset);
+	trailer_stop->progusage[0] = trailer_start->timestamp;
+
+	return 1;
+}
+
+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,
+				enum cpumf_ctr_set set)
+{
+	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 (set) {
+	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;
+	case CPUMF_CTR_SET_MAX:
+		err = -EOPNOTSUPP;
+	}
+
+	put_cpu_var(cpu_cf_events);
+	return err;
+}
+
+static int validate_ctr_auth(const struct hw_perf_event *hwc)
+{
+	struct cpu_cf_events *cpuhw;
+	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.
+	 */
+	if (!(hwc->config_base & 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 | cpuhw->dev_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);
+	inactive |= cpuhw->dev_state;
+	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 void cpumf_hw_inuse(void)
+{
+	mutex_lock(&pmc_reserve_mutex);
+	if (atomic_inc_return(&num_events) == 1)
+		__kernel_cpumcf_begin();
+	mutex_unlock(&pmc_reserve_mutex);
+}
+
+static int is_userspace_event(u64 ev)
+{
+	return cpumf_generic_events_user[PERF_COUNT_HW_CPU_CYCLES] == ev ||
+	       cpumf_generic_events_user[PERF_COUNT_HW_INSTRUCTIONS] == ev;
+}
+
+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;
+		if (!attr->exclude_user && attr->exclude_kernel) {
+			/*
+			 * Count user space (problem-state) only
+			 * Handle events 32 and 33 as 0:u and 1:u
+			 */
+			if (!is_userspace_event(ev)) {
+				if (ev >= ARRAY_SIZE(cpumf_generic_events_user))
+					return -EOPNOTSUPP;
+				ev = cpumf_generic_events_user[ev];
+			}
+		} else if (!attr->exclude_kernel && attr->exclude_user) {
+			/* No support for kernel space counters only */
+			return -EOPNOTSUPP;
+		} else {
+			/* Count user and kernel space, incl. events 32 + 33 */
+			if (!is_userspace_event(ev)) {
+				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' as bit mask.
+		 * It is later used to enable/disable the counter(s).
+		 */
+		hwc->config = ev;
+		hwc->config_base = cpumf_ctr_ctl[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 */
+	cpumf_hw_inuse();
+	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, set);
+
+	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;
+	int i;
+
+	if (!(hwc->state & PERF_HES_STOPPED))
+		return;
+
+	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.
+	 */
+	if (hwc->config == PERF_EVENT_CPUM_CF_DIAG) {
+		cpuhw->usedss = cfdiag_getctr(cpuhw->start,
+					      sizeof(cpuhw->start),
+					      hwc->config_base, true);
+	} else {
+		hw_perf_event_reset(event);
+	}
+
+	/* Increment refcount for counter sets */
+	for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i)
+		if ((hwc->config_base & cpumf_ctr_ctl[i]))
+			atomic_inc(&cpuhw->ctr_set[i]);
+}
+
+/* Create perf event sample with the counter sets as raw data.	The sample
+ * is then pushed to the event subsystem and the function checks for
+ * possible event overflows. If an event overflow occurs, the PMU is
+ * stopped.
+ *
+ * Return non-zero if an event overflow occurred.
+ */
+static int cfdiag_push_sample(struct perf_event *event,
+			      struct cpu_cf_events *cpuhw)
+{
+	struct perf_sample_data data;
+	struct perf_raw_record raw;
+	struct pt_regs regs;
+	int overflow;
+
+	/* Setup perf sample */
+	perf_sample_data_init(&data, 0, event->hw.last_period);
+	memset(&regs, 0, sizeof(regs));
+	memset(&raw, 0, sizeof(raw));
+
+	if (event->attr.sample_type & PERF_SAMPLE_CPU)
+		data.cpu_entry.cpu = event->cpu;
+	if (event->attr.sample_type & PERF_SAMPLE_RAW) {
+		raw.frag.size = cpuhw->usedss;
+		raw.frag.data = cpuhw->stop;
+		raw.size = raw.frag.size;
+		data.raw = &raw;
+		data.sample_flags |= PERF_SAMPLE_RAW;
+	}
+
+	overflow = perf_event_overflow(event, &data, &regs);
+	debug_sprintf_event(cf_dbg, 3,
+			    "%s event %#llx sample_type %#llx raw %d ov %d\n",
+			    __func__, event->hw.config,
+			    event->attr.sample_type, raw.size, overflow);
+	if (overflow)
+		event->pmu->stop(event, 0);
+
+	perf_event_update_userpage(event);
+	return overflow;
+}
+
+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;
+	int i;
+
+	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.
+		 */
+		for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i) {
+			if (!(hwc->config_base & cpumf_ctr_ctl[i]))
+				continue;
+			if (!atomic_dec_return(&cpuhw->ctr_set[i]))
+				ctr_set_stop(&cpuhw->state, cpumf_ctr_ctl[i]);
+		}
+		hwc->state |= PERF_HES_STOPPED;
+	}
+
+	if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+		if (hwc->config == PERF_EVENT_CPUM_CF_DIAG) {
+			local64_inc(&event->count);
+			cpuhw->usedss = cfdiag_getctr(cpuhw->stop,
+						      sizeof(cpuhw->stop),
+						      event->hw.config_base,
+						      false);
+			if (cfdiag_diffctr(cpuhw, event->hw.config_base))
+				cfdiag_push_sample(event, cpuhw);
+		} else if (cpuhw->flags & PMU_F_RESERVED) {
+			/* Only update when PMU not hotplugged off */
+			hw_perf_event_update(event);
+		}
+		hwc->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);
+
+	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);
+
+	return 0;
+}
+
+static void cpumf_pmu_del(struct perf_event *event, int flags)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	int i;
+
+	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.
+	 */
+	for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i)
+		if (!atomic_read(&cpuhw->ctr_set[i]))
+			ctr_set_disable(&cpuhw->state, cpumf_ctr_ctl[i]);
+}
+
+/* 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,
+};
+
+static int cfset_init(void);
+static int __init cpumf_pmu_init(void)
+{
+	int rc;
+
+	if (!kernel_cpumcf_avail())
+		return -ENODEV;
+
+	/* Setup s390dbf facility */
+	cf_dbg = debug_register(KMSG_COMPONENT, 2, 1, 128);
+	if (!cf_dbg) {
+		pr_err("Registration of s390dbf(cpum_cf) failed\n");
+		return -ENOMEM;
+	}
+	debug_register_view(cf_dbg, &debug_sprintf_view);
+
+	cpumf_pmu.attr_groups = cpumf_cf_event_group();
+	rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", -1);
+	if (rc) {
+		debug_unregister_view(cf_dbg, &debug_sprintf_view);
+		debug_unregister(cf_dbg);
+		pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc);
+	} else if (stccm_avail()) {	/* Setup counter set device */
+		cfset_init();
+	}
+	return rc;
+}
+
+/* Support for the CPU Measurement Facility counter set extraction using
+ * device /dev/hwctr. This allows user space programs to extract complete
+ * counter set via normal file operations.
+ */
+
+static atomic_t cfset_opencnt = ATOMIC_INIT(0);		/* Access count */
+static DEFINE_MUTEX(cfset_ctrset_mutex);/* Synchronize access to hardware */
+struct cfset_call_on_cpu_parm {		/* Parm struct for smp_call_on_cpu */
+	unsigned int sets;		/* Counter set bit mask */
+	atomic_t cpus_ack;		/* # CPUs successfully executed func */
+};
+
+static struct cfset_session {		/* CPUs and counter set bit mask */
+	struct list_head head;		/* Head of list of active processes */
+} cfset_session = {
+	.head = LIST_HEAD_INIT(cfset_session.head)
+};
+
+struct cfset_request {			/* CPUs and counter set bit mask */
+	unsigned long ctrset;		/* Bit mask of counter set to read */
+	cpumask_t mask;			/* CPU mask to read from */
+	struct list_head node;		/* Chain to cfset_session.head */
+};
+
+static void cfset_session_init(void)
+{
+	INIT_LIST_HEAD(&cfset_session.head);
+}
+
+/* Remove current request from global bookkeeping. Maintain a counter set bit
+ * mask on a per CPU basis.
+ * Done in process context under mutex protection.
+ */
+static void cfset_session_del(struct cfset_request *p)
+{
+	list_del(&p->node);
+}
+
+/* Add current request to global bookkeeping. Maintain a counter set bit mask
+ * on a per CPU basis.
+ * Done in process context under mutex protection.
+ */
+static void cfset_session_add(struct cfset_request *p)
+{
+	list_add(&p->node, &cfset_session.head);
+}
+
+/* The /dev/hwctr device access uses PMU_F_IN_USE to mark the device access
+ * path is currently used.
+ * The cpu_cf_events::dev_state is used to denote counter sets in use by this
+ * interface. It is always or'ed in. If this interface is not active, its
+ * value is zero and no additional counter sets will be included.
+ *
+ * The cpu_cf_events::state is used by the perf_event_open SVC and remains
+ * unchanged.
+ *
+ * perf_pmu_enable() and perf_pmu_enable() and its call backs
+ * cpumf_pmu_enable() and  cpumf_pmu_disable() are called by the
+ * performance measurement subsystem to enable per process
+ * CPU Measurement counter facility.
+ * The XXX_enable() and XXX_disable functions are used to turn off
+ * x86 performance monitoring interrupt (PMI) during scheduling.
+ * s390 uses these calls to temporarily stop and resume the active CPU
+ * counters sets during scheduling.
+ *
+ * We do allow concurrent access of perf_event_open() SVC and /dev/hwctr
+ * device access.  The perf_event_open() SVC interface makes a lot of effort
+ * to only run the counters while the calling process is actively scheduled
+ * to run.
+ * When /dev/hwctr interface is also used at the same time, the counter sets
+ * will keep running, even when the process is scheduled off a CPU.
+ * However this is not a problem and does not lead to wrong counter values
+ * for the perf_event_open() SVC. The current counter value will be recorded
+ * during schedule-in. At schedule-out time the current counter value is
+ * extracted again and the delta is calculated and added to the event.
+ */
+/* Stop all counter sets via ioctl interface */
+static void cfset_ioctl_off(void *parm)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	struct cfset_call_on_cpu_parm *p = parm;
+	int rc;
+
+	/* Check if any counter set used by /dev/hwc */
+	for (rc = CPUMF_CTR_SET_BASIC; rc < CPUMF_CTR_SET_MAX; ++rc)
+		if ((p->sets & cpumf_ctr_ctl[rc])) {
+			if (!atomic_dec_return(&cpuhw->ctr_set[rc])) {
+				ctr_set_disable(&cpuhw->dev_state,
+						cpumf_ctr_ctl[rc]);
+				ctr_set_stop(&cpuhw->dev_state,
+					     cpumf_ctr_ctl[rc]);
+			}
+		}
+	/* Keep perf_event_open counter sets */
+	rc = lcctl(cpuhw->dev_state | cpuhw->state);
+	if (rc)
+		pr_err("Counter set stop %#llx of /dev/%s failed rc=%i\n",
+		       cpuhw->state, S390_HWCTR_DEVICE, rc);
+	if (!cpuhw->dev_state)
+		cpuhw->flags &= ~PMU_F_IN_USE;
+	debug_sprintf_event(cf_dbg, 4, "%s rc %d state %#llx dev_state %#llx\n",
+			    __func__, rc, cpuhw->state, cpuhw->dev_state);
+}
+
+/* Start counter sets on particular CPU */
+static void cfset_ioctl_on(void *parm)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	struct cfset_call_on_cpu_parm *p = parm;
+	int rc;
+
+	cpuhw->flags |= PMU_F_IN_USE;
+	ctr_set_enable(&cpuhw->dev_state, p->sets);
+	ctr_set_start(&cpuhw->dev_state, p->sets);
+	for (rc = CPUMF_CTR_SET_BASIC; rc < CPUMF_CTR_SET_MAX; ++rc)
+		if ((p->sets & cpumf_ctr_ctl[rc]))
+			atomic_inc(&cpuhw->ctr_set[rc]);
+	rc = lcctl(cpuhw->dev_state | cpuhw->state);	/* Start counter sets */
+	if (!rc)
+		atomic_inc(&p->cpus_ack);
+	else
+		pr_err("Counter set start %#llx of /dev/%s failed rc=%i\n",
+		       cpuhw->dev_state | cpuhw->state, S390_HWCTR_DEVICE, rc);
+	debug_sprintf_event(cf_dbg, 4, "%s rc %d state %#llx dev_state %#llx\n",
+			    __func__, rc, cpuhw->state, cpuhw->dev_state);
+}
+
+static void cfset_release_cpu(void *p)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	int rc;
+
+	debug_sprintf_event(cf_dbg, 4, "%s state %#llx dev_state %#llx\n",
+			    __func__, cpuhw->state, cpuhw->dev_state);
+	cpuhw->dev_state = 0;
+	rc = lcctl(cpuhw->state);	/* Keep perf_event_open counter sets */
+	if (rc)
+		pr_err("Counter set release %#llx of /dev/%s failed rc=%i\n",
+		       cpuhw->state, S390_HWCTR_DEVICE, rc);
+}
+
+/* This modifies the process CPU mask to adopt it to the currently online
+ * CPUs. Offline CPUs can not be addresses. This call terminates the access
+ * and is usually followed by close() or a new iotcl(..., START, ...) which
+ * creates a new request structure.
+ */
+static void cfset_all_stop(struct cfset_request *req)
+{
+	struct cfset_call_on_cpu_parm p = {
+		.sets = req->ctrset,
+	};
+
+	cpumask_and(&req->mask, &req->mask, cpu_online_mask);
+	on_each_cpu_mask(&req->mask, cfset_ioctl_off, &p, 1);
+}
+
+/* Release function is also called when application gets terminated without
+ * doing a proper ioctl(..., S390_HWCTR_STOP, ...) command.
+ */
+static int cfset_release(struct inode *inode, struct file *file)
+{
+	mutex_lock(&cfset_ctrset_mutex);
+	/* Open followed by close/exit has no private_data */
+	if (file->private_data) {
+		cfset_all_stop(file->private_data);
+		cfset_session_del(file->private_data);
+		kfree(file->private_data);
+		file->private_data = NULL;
+	}
+	if (!atomic_dec_return(&cfset_opencnt))
+		on_each_cpu(cfset_release_cpu, NULL, 1);
+	mutex_unlock(&cfset_ctrset_mutex);
+
+	hw_perf_event_destroy(NULL);
+	return 0;
+}
+
+static int cfset_open(struct inode *inode, struct file *file)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	mutex_lock(&cfset_ctrset_mutex);
+	if (atomic_inc_return(&cfset_opencnt) == 1)
+		cfset_session_init();
+	mutex_unlock(&cfset_ctrset_mutex);
+
+	cpumf_hw_inuse();
+	file->private_data = NULL;
+	/* nonseekable_open() never fails */
+	return nonseekable_open(inode, file);
+}
+
+static int cfset_all_start(struct cfset_request *req)
+{
+	struct cfset_call_on_cpu_parm p = {
+		.sets = req->ctrset,
+		.cpus_ack = ATOMIC_INIT(0),
+	};
+	cpumask_var_t mask;
+	int rc = 0;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+	cpumask_and(mask, &req->mask, cpu_online_mask);
+	on_each_cpu_mask(mask, cfset_ioctl_on, &p, 1);
+	if (atomic_read(&p.cpus_ack) != cpumask_weight(mask)) {
+		on_each_cpu_mask(mask, cfset_ioctl_off, &p, 1);
+		rc = -EIO;
+		debug_sprintf_event(cf_dbg, 4, "%s CPUs missing", __func__);
+	}
+	free_cpumask_var(mask);
+	return rc;
+}
+
+
+/* Return the maximum required space for all possible CPUs in case one
+ * CPU will be onlined during the START, READ, STOP cycles.
+ * To find out the size of the counter sets, any one CPU will do. They
+ * all have the same counter sets.
+ */
+static size_t cfset_needspace(unsigned int sets)
+{
+	struct cpu_cf_events *cpuhw = get_cpu_ptr(&cpu_cf_events);
+	size_t bytes = 0;
+	int i;
+
+	for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i) {
+		if (!(sets & cpumf_ctr_ctl[i]))
+			continue;
+		bytes += cpum_cf_ctrset_size(i, &cpuhw->info) * sizeof(u64) +
+			 sizeof(((struct s390_ctrset_setdata *)0)->set) +
+			 sizeof(((struct s390_ctrset_setdata *)0)->no_cnts);
+	}
+	bytes = sizeof(((struct s390_ctrset_read *)0)->no_cpus) + nr_cpu_ids *
+		(bytes + sizeof(((struct s390_ctrset_cpudata *)0)->cpu_nr) +
+		     sizeof(((struct s390_ctrset_cpudata *)0)->no_sets));
+	put_cpu_ptr(&cpu_cf_events);
+	return bytes;
+}
+
+static int cfset_all_copy(unsigned long arg, cpumask_t *mask)
+{
+	struct s390_ctrset_read __user *ctrset_read;
+	unsigned int cpu, cpus, rc;
+	void __user *uptr;
+
+	ctrset_read = (struct s390_ctrset_read __user *)arg;
+	uptr = ctrset_read->data;
+	for_each_cpu(cpu, mask) {
+		struct cpu_cf_events *cpuhw = per_cpu_ptr(&cpu_cf_events, cpu);
+		struct s390_ctrset_cpudata __user *ctrset_cpudata;
+
+		ctrset_cpudata = uptr;
+		rc  = put_user(cpu, &ctrset_cpudata->cpu_nr);
+		rc |= put_user(cpuhw->sets, &ctrset_cpudata->no_sets);
+		rc |= copy_to_user(ctrset_cpudata->data, cpuhw->data,
+				   cpuhw->used);
+		if (rc)
+			return -EFAULT;
+		uptr += sizeof(struct s390_ctrset_cpudata) + cpuhw->used;
+		cond_resched();
+	}
+	cpus = cpumask_weight(mask);
+	if (put_user(cpus, &ctrset_read->no_cpus))
+		return -EFAULT;
+	debug_sprintf_event(cf_dbg, 4, "%s copied %ld\n", __func__,
+			    uptr - (void __user *)ctrset_read->data);
+	return 0;
+}
+
+static size_t cfset_cpuset_read(struct s390_ctrset_setdata *p, int ctrset,
+				int ctrset_size, size_t room)
+{
+	size_t need = 0;
+	int rc = -1;
+
+	need = sizeof(*p) + sizeof(u64) * ctrset_size;
+	if (need <= room) {
+		p->set = cpumf_ctr_ctl[ctrset];
+		p->no_cnts = ctrset_size;
+		rc = ctr_stcctm(ctrset, ctrset_size, (u64 *)p->cv);
+		if (rc == 3)		/* Nothing stored */
+			need = 0;
+	}
+	return need;
+}
+
+/* Read all counter sets. */
+static void cfset_cpu_read(void *parm)
+{
+	struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+	struct cfset_call_on_cpu_parm *p = parm;
+	int set, set_size;
+	size_t space;
+
+	/* No data saved yet */
+	cpuhw->used = 0;
+	cpuhw->sets = 0;
+	memset(cpuhw->data, 0, sizeof(cpuhw->data));
+
+	/* Scan the counter sets */
+	for (set = CPUMF_CTR_SET_BASIC; set < CPUMF_CTR_SET_MAX; ++set) {
+		struct s390_ctrset_setdata *sp = (void *)cpuhw->data +
+						 cpuhw->used;
+
+		if (!(p->sets & cpumf_ctr_ctl[set]))
+			continue;	/* Counter set not in list */
+		set_size = cpum_cf_ctrset_size(set, &cpuhw->info);
+		space = sizeof(cpuhw->data) - cpuhw->used;
+		space = cfset_cpuset_read(sp, set, set_size, space);
+		if (space) {
+			cpuhw->used += space;
+			cpuhw->sets += 1;
+		}
+	}
+	debug_sprintf_event(cf_dbg, 4, "%s sets %d used %zd\n", __func__,
+			    cpuhw->sets, cpuhw->used);
+}
+
+static int cfset_all_read(unsigned long arg, struct cfset_request *req)
+{
+	struct cfset_call_on_cpu_parm p;
+	cpumask_var_t mask;
+	int rc;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	p.sets = req->ctrset;
+	cpumask_and(mask, &req->mask, cpu_online_mask);
+	on_each_cpu_mask(mask, cfset_cpu_read, &p, 1);
+	rc = cfset_all_copy(arg, mask);
+	free_cpumask_var(mask);
+	return rc;
+}
+
+static long cfset_ioctl_read(unsigned long arg, struct cfset_request *req)
+{
+	struct s390_ctrset_read read;
+	int ret = -ENODATA;
+
+	if (req && req->ctrset) {
+		if (copy_from_user(&read, (char __user *)arg, sizeof(read)))
+			return -EFAULT;
+		ret = cfset_all_read(arg, req);
+	}
+	return ret;
+}
+
+static long cfset_ioctl_stop(struct file *file)
+{
+	struct cfset_request *req = file->private_data;
+	int ret = -ENXIO;
+
+	if (req) {
+		cfset_all_stop(req);
+		cfset_session_del(req);
+		kfree(req);
+		file->private_data = NULL;
+		ret = 0;
+	}
+	return ret;
+}
+
+static long cfset_ioctl_start(unsigned long arg, struct file *file)
+{
+	struct s390_ctrset_start __user *ustart;
+	struct s390_ctrset_start start;
+	struct cfset_request *preq;
+	void __user *umask;
+	unsigned int len;
+	int ret = 0;
+	size_t need;
+
+	if (file->private_data)
+		return -EBUSY;
+	ustart = (struct s390_ctrset_start __user *)arg;
+	if (copy_from_user(&start, ustart, sizeof(start)))
+		return -EFAULT;
+	if (start.version != S390_HWCTR_START_VERSION)
+		return -EINVAL;
+	if (start.counter_sets & ~(cpumf_ctr_ctl[CPUMF_CTR_SET_BASIC] |
+				   cpumf_ctr_ctl[CPUMF_CTR_SET_USER] |
+				   cpumf_ctr_ctl[CPUMF_CTR_SET_CRYPTO] |
+				   cpumf_ctr_ctl[CPUMF_CTR_SET_EXT] |
+				   cpumf_ctr_ctl[CPUMF_CTR_SET_MT_DIAG]))
+		return -EINVAL;		/* Invalid counter set */
+	if (!start.counter_sets)
+		return -EINVAL;		/* No counter set at all? */
+
+	preq = kzalloc(sizeof(*preq), GFP_KERNEL);
+	if (!preq)
+		return -ENOMEM;
+	cpumask_clear(&preq->mask);
+	len = min_t(u64, start.cpumask_len, cpumask_size());
+	umask = (void __user *)start.cpumask;
+	if (copy_from_user(&preq->mask, umask, len)) {
+		kfree(preq);
+		return -EFAULT;
+	}
+	if (cpumask_empty(&preq->mask)) {
+		kfree(preq);
+		return -EINVAL;
+	}
+	need = cfset_needspace(start.counter_sets);
+	if (put_user(need, &ustart->data_bytes)) {
+		kfree(preq);
+		return -EFAULT;
+	}
+	preq->ctrset = start.counter_sets;
+	ret = cfset_all_start(preq);
+	if (!ret) {
+		cfset_session_add(preq);
+		file->private_data = preq;
+		debug_sprintf_event(cf_dbg, 4, "%s set %#lx need %ld ret %d\n",
+				    __func__, preq->ctrset, need, ret);
+	} else {
+		kfree(preq);
+	}
+	return ret;
+}
+
+/* Entry point to the /dev/hwctr device interface.
+ * The ioctl system call supports three subcommands:
+ * S390_HWCTR_START: Start the specified counter sets on a CPU list. The
+ *    counter set keeps running until explicitly stopped. Returns the number
+ *    of bytes needed to store the counter values. If another S390_HWCTR_START
+ *    ioctl subcommand is called without a previous S390_HWCTR_STOP stop
+ *    command on the same file descriptor, -EBUSY is returned.
+ * S390_HWCTR_READ: Read the counter set values from specified CPU list given
+ *    with the S390_HWCTR_START command.
+ * S390_HWCTR_STOP: Stops the counter sets on the CPU list given with the
+ *    previous S390_HWCTR_START subcommand.
+ */
+static long cfset_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int ret;
+
+	cpus_read_lock();
+	mutex_lock(&cfset_ctrset_mutex);
+	switch (cmd) {
+	case S390_HWCTR_START:
+		ret = cfset_ioctl_start(arg, file);
+		break;
+	case S390_HWCTR_STOP:
+		ret = cfset_ioctl_stop(file);
+		break;
+	case S390_HWCTR_READ:
+		ret = cfset_ioctl_read(arg, file->private_data);
+		break;
+	default:
+		ret = -ENOTTY;
+		break;
+	}
+	mutex_unlock(&cfset_ctrset_mutex);
+	cpus_read_unlock();
+	return ret;
+}
+
+static const struct file_operations cfset_fops = {
+	.owner = THIS_MODULE,
+	.open = cfset_open,
+	.release = cfset_release,
+	.unlocked_ioctl	= cfset_ioctl,
+	.compat_ioctl = cfset_ioctl,
+	.llseek = no_llseek
+};
+
+static struct miscdevice cfset_dev = {
+	.name	= S390_HWCTR_DEVICE,
+	.minor	= MISC_DYNAMIC_MINOR,
+	.fops	= &cfset_fops,
+};
+
+/* Hotplug add of a CPU. Scan through all active processes and add
+ * that CPU to the list of CPUs supplied with ioctl(..., START, ...).
+ */
+int cfset_online_cpu(unsigned int cpu)
+{
+	struct cfset_call_on_cpu_parm p;
+	struct cfset_request *rp;
+
+	mutex_lock(&cfset_ctrset_mutex);
+	if (!list_empty(&cfset_session.head)) {
+		list_for_each_entry(rp, &cfset_session.head, node) {
+			p.sets = rp->ctrset;
+			cfset_ioctl_on(&p);
+			cpumask_set_cpu(cpu, &rp->mask);
+		}
+	}
+	mutex_unlock(&cfset_ctrset_mutex);
+	return 0;
+}
+
+/* Hotplug remove of a CPU. Scan through all active processes and clear
+ * that CPU from the list of CPUs supplied with ioctl(..., START, ...).
+ */
+int cfset_offline_cpu(unsigned int cpu)
+{
+	struct cfset_call_on_cpu_parm p;
+	struct cfset_request *rp;
+
+	mutex_lock(&cfset_ctrset_mutex);
+	if (!list_empty(&cfset_session.head)) {
+		list_for_each_entry(rp, &cfset_session.head, node) {
+			p.sets = rp->ctrset;
+			cfset_ioctl_off(&p);
+			cpumask_clear_cpu(cpu, &rp->mask);
+		}
+	}
+	mutex_unlock(&cfset_ctrset_mutex);
+	return 0;
+}
+
+static void cfdiag_read(struct perf_event *event)
+{
+	debug_sprintf_event(cf_dbg, 3, "%s event %#llx count %ld\n", __func__,
+			    event->attr.config, local64_read(&event->count));
+}
+
+static int get_authctrsets(void)
+{
+	struct cpu_cf_events *cpuhw;
+	unsigned long auth = 0;
+	enum cpumf_ctr_set i;
+
+	cpuhw = &get_cpu_var(cpu_cf_events);
+	for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i) {
+		if (cpuhw->info.auth_ctl & cpumf_ctr_ctl[i])
+			auth |= cpumf_ctr_ctl[i];
+	}
+	put_cpu_var(cpu_cf_events);
+	return auth;
+}
+
+/* Setup the event. Test for authorized counter sets and only include counter
+ * sets which are authorized at the time of the setup. Including unauthorized
+ * counter sets result in specification exception (and panic).
+ */
+static int cfdiag_event_init2(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+	int err = 0;
+
+	/* Set sample_period to indicate sampling */
+	event->hw.config = attr->config;
+	event->hw.sample_period = attr->sample_period;
+	local64_set(&event->hw.period_left, event->hw.sample_period);
+	local64_set(&event->count, 0);
+	event->hw.last_period = event->hw.sample_period;
+
+	/* Add all authorized counter sets to config_base. The
+	 * the hardware init function is either called per-cpu or just once
+	 * for all CPUS (event->cpu == -1).  This depends on the whether
+	 * counting is started for all CPUs or on a per workload base where
+	 * the perf event moves from one CPU to another CPU.
+	 * Checking the authorization on any CPU is fine as the hardware
+	 * applies the same authorization settings to all CPUs.
+	 */
+	event->hw.config_base = get_authctrsets();
+
+	/* No authorized counter sets, nothing to count/sample */
+	if (!event->hw.config_base)
+		err = -EINVAL;
+
+	debug_sprintf_event(cf_dbg, 5, "%s err %d config_base %#lx\n",
+			    __func__, err, event->hw.config_base);
+	return err;
+}
+
+static int cfdiag_event_init(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+	int err = -ENOENT;
+
+	if (event->attr.config != PERF_EVENT_CPUM_CF_DIAG ||
+	    event->attr.type != event->pmu->type)
+		goto out;
+
+	/* Raw events are used to access counters directly,
+	 * hence do not permit excludes.
+	 * This event is useless without PERF_SAMPLE_RAW to return counter set
+	 * values as raw data.
+	 */
+	if (attr->exclude_kernel || attr->exclude_user || attr->exclude_hv ||
+	    !(attr->sample_type & (PERF_SAMPLE_CPU | PERF_SAMPLE_RAW))) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	/* Initialize for using the CPU-measurement counter facility */
+	cpumf_hw_inuse();
+	event->destroy = hw_perf_event_destroy;
+
+	err = cfdiag_event_init2(event);
+	if (unlikely(err))
+		event->destroy(event);
+out:
+	return err;
+}
+
+/* Create cf_diag/events/CF_DIAG event sysfs file. This counter is used
+ * to collect the complete counter sets for a scheduled process. Target
+ * are complete counter sets attached as raw data to the artificial event.
+ * This results in complete counter sets available when a process is
+ * scheduled. Contains the delta of every counter while the process was
+ * running.
+ */
+CPUMF_EVENT_ATTR(CF_DIAG, CF_DIAG, PERF_EVENT_CPUM_CF_DIAG);
+
+static struct attribute *cfdiag_events_attr[] = {
+	CPUMF_EVENT_PTR(CF_DIAG, CF_DIAG),
+	NULL,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-63");
+
+static struct attribute *cfdiag_format_attr[] = {
+	&format_attr_event.attr,
+	NULL,
+};
+
+static struct attribute_group cfdiag_events_group = {
+	.name = "events",
+	.attrs = cfdiag_events_attr,
+};
+static struct attribute_group cfdiag_format_group = {
+	.name = "format",
+	.attrs = cfdiag_format_attr,
+};
+static const struct attribute_group *cfdiag_attr_groups[] = {
+	&cfdiag_events_group,
+	&cfdiag_format_group,
+	NULL,
+};
+
+/* Performance monitoring unit for event CF_DIAG. Since this event
+ * is also started and stopped via the perf_event_open() system call, use
+ * the same event enable/disable call back functions. They do not
+ * have a pointer to the perf_event strcture as first parameter.
+ *
+ * The functions XXX_add, XXX_del, XXX_start and XXX_stop are also common.
+ * Reuse them and distinguish the event (always first parameter) via
+ * 'config' member.
+ */
+static struct pmu cf_diag = {
+	.task_ctx_nr  = perf_sw_context,
+	.event_init   = cfdiag_event_init,
+	.pmu_enable   = cpumf_pmu_enable,
+	.pmu_disable  = cpumf_pmu_disable,
+	.add	      = cpumf_pmu_add,
+	.del	      = cpumf_pmu_del,
+	.start	      = cpumf_pmu_start,
+	.stop	      = cpumf_pmu_stop,
+	.read	      = cfdiag_read,
+
+	.attr_groups  = cfdiag_attr_groups
+};
+
+/* Calculate memory needed to store all counter sets together with header and
+ * trailer data. This is independent of the counter set authorization which
+ * can vary depending on the configuration.
+ */
+static size_t cfdiag_maxsize(struct cpumf_ctr_info *info)
+{
+	size_t max_size = sizeof(struct cf_trailer_entry);
+	enum cpumf_ctr_set i;
+
+	for (i = CPUMF_CTR_SET_BASIC; i < CPUMF_CTR_SET_MAX; ++i) {
+		size_t size = cpum_cf_ctrset_size(i, info);
+
+		if (size)
+			max_size += size * sizeof(u64) +
+				    sizeof(struct cf_ctrset_entry);
+	}
+	return max_size;
+}
+
+/* Get the CPU speed, try sampling facility first and CPU attributes second. */
+static void cfdiag_get_cpu_speed(void)
+{
+	unsigned long mhz;
+
+	if (cpum_sf_avail()) {			/* Sampling facility first */
+		struct hws_qsi_info_block si;
+
+		memset(&si, 0, sizeof(si));
+		if (!qsi(&si)) {
+			cfdiag_cpu_speed = si.cpu_speed;
+			return;
+		}
+	}
+
+	/* Fallback: CPU speed extract static part. Used in case
+	 * CPU Measurement Sampling Facility is turned off.
+	 */
+	mhz = __ecag(ECAG_CPU_ATTRIBUTE, 0);
+	if (mhz != -1UL)
+		cfdiag_cpu_speed = mhz & 0xffffffff;
+}
+
+static int cfset_init(void)
+{
+	struct cpumf_ctr_info info;
+	size_t need;
+	int rc;
+
+	if (qctri(&info))
+		return -ENODEV;
+
+	cfdiag_get_cpu_speed();
+	/* Make sure the counter set data fits into predefined buffer. */
+	need = cfdiag_maxsize(&info);
+	if (need > sizeof(((struct cpu_cf_events *)0)->start)) {
+		pr_err("Insufficient memory for PMU(cpum_cf_diag) need=%zu\n",
+		       need);
+		return -ENOMEM;
+	}
+
+	rc = misc_register(&cfset_dev);
+	if (rc) {
+		pr_err("Registration of /dev/%s failed rc=%i\n",
+		       cfset_dev.name, rc);
+		goto out;
+	}
+
+	rc = perf_pmu_register(&cf_diag, "cpum_cf_diag", -1);
+	if (rc) {
+		misc_deregister(&cfset_dev);
+		pr_err("Registration of PMU(cpum_cf_diag) failed with rc=%i\n",
+		       rc);
+	}
+out:
+	return rc;
+}
+
+device_initcall(cpumf_pmu_init);