--- /dev/null
+/*
+ * Performance event support for the System z CPU-measurement Sampling Facility
+ *
+ * Copyright IBM Corp. 2013
+ * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ */
+#define KMSG_COMPONENT "cpum_sf"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/perf_event.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/export.h>
+#include <asm/cpu_mf.h>
+#include <asm/irq.h>
+#include <asm/debug.h>
+#include <asm/timex.h>
+
+/* Minimum number of sample-data-block-tables:
+ * At least one table is required for the sampling buffer structure.
+ * A single table contains up to 511 pointers to sample-data-blocks.
+ */
+#define CPUM_SF_MIN_SDBT 1
+
+/* Minimum number of sample-data-blocks:
+ * The minimum designates a single page for sample-data-block, i.e.,
+ * up to 126 sample-data-blocks with a size of 32 bytes (bsdes).
+ */
+#define CPUM_SF_MIN_SDB 126
+
+/* Maximum number of sample-data-blocks:
+ * The maximum number designates approx. 256K per CPU including
+ * the given number of sample-data-blocks and taking the number
+ * of sample-data-block tables into account.
+ *
+ * Later, this number can be increased for extending the sampling
+ * buffer, for example, by factor 2 (512K) or 4 (1M).
+ */
+#define CPUM_SF_MAX_SDB 6471
+
+struct sf_buffer {
+ unsigned long sdbt; /* Sample-data-block-table origin */
+ /* buffer characteristics (required for buffer increments) */
+ unsigned long num_sdb; /* Number of sample-data-blocks */
+ unsigned long tail; /* last sample-data-block-table */
+};
+
+struct cpu_hw_sf {
+ /* CPU-measurement sampling information block */
+ struct hws_qsi_info_block qsi;
+ struct hws_lsctl_request_block lsctl;
+ struct sf_buffer sfb; /* Sampling buffer */
+ unsigned int flags; /* Status flags */
+ struct perf_event *event; /* Scheduled perf event */
+};
+static DEFINE_PER_CPU(struct cpu_hw_sf, cpu_hw_sf);
+
+/* Debug feature */
+static debug_info_t *sfdbg;
+
+/*
+ * sf_buffer_available() - Check for an allocated sampling buffer
+ */
+static int sf_buffer_available(struct cpu_hw_sf *cpuhw)
+{
+ return (cpuhw->sfb.sdbt) ? 1 : 0;
+}
+
+/*
+ * deallocate sampling facility buffer
+ */
+static void free_sampling_buffer(struct sf_buffer *sfb)
+{
+ unsigned long sdbt, *curr;
+
+ if (!sfb->sdbt)
+ return;
+
+ sdbt = sfb->sdbt;
+ curr = (unsigned long *) sdbt;
+
+ /* we'll free the SDBT after all SDBs are processed... */
+ while (1) {
+ if (!*curr || !sdbt)
+ break;
+
+ /* watch for link entry reset if found */
+ if (is_link_entry(curr)) {
+ curr = get_next_sdbt(curr);
+ if (sdbt)
+ free_page(sdbt);
+
+ /* we are done if we reach the origin */
+ if ((unsigned long) curr == sfb->sdbt)
+ break;
+ else
+ sdbt = (unsigned long) curr;
+ } else {
+ /* process SDB pointer */
+ if (*curr) {
+ free_page(*curr);
+ curr++;
+ }
+ }
+ }
+
+ debug_sprintf_event(sfdbg, 5,
+ "free_sampling_buffer: freed sdbt=%0lx\n", sfb->sdbt);
+ memset(sfb, 0, sizeof(*sfb));
+}
+
+/*
+ * allocate_sampling_buffer() - allocate sampler memory
+ *
+ * Allocates and initializes a sampling buffer structure using the
+ * specified number of sample-data-blocks (SDB). For each allocation,
+ * a 4K page is used. The number of sample-data-block-tables (SDBT)
+ * are calculated from SDBs.
+ * Also set the ALERT_REQ mask in each SDBs trailer.
+ *
+ * Returns zero on success, non-zero otherwise.
+ */
+static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb)
+{
+ int j, k, rc;
+ unsigned long *sdbt, *tail, *trailer;
+ unsigned long sdb;
+ unsigned long num_sdbt, sdb_per_table;
+
+ if (sfb->sdbt)
+ return -EINVAL;
+ sfb->num_sdb = 0;
+
+ /* Compute the number of required sample-data-block-tables (SDBT) */
+ num_sdbt = num_sdb / ((PAGE_SIZE - 8) / 8);
+ if (num_sdbt < CPUM_SF_MIN_SDBT)
+ num_sdbt = CPUM_SF_MIN_SDBT;
+ sdb_per_table = (PAGE_SIZE - 8) / 8;
+
+ debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: num_sdbt=%lu "
+ "num_sdb=%lu sdb_per_table=%lu\n",
+ num_sdbt, num_sdb, sdb_per_table);
+ sdbt = NULL;
+ tail = sdbt;
+
+ for (j = 0; j < num_sdbt; j++) {
+ sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL);
+ if (!sdbt) {
+ rc = -ENOMEM;
+ goto allocate_sdbt_error;
+ }
+
+ /* save origin of sample-data-block-table */
+ if (!sfb->sdbt)
+ sfb->sdbt = (unsigned long) sdbt;
+
+ /* link current page to tail of chain */
+ if (tail)
+ *tail = (unsigned long)(void *) sdbt + 1;
+
+ for (k = 0; k < num_sdb && k < sdb_per_table; k++) {
+ /* get and set SDB page */
+ sdb = get_zeroed_page(GFP_KERNEL);
+ if (!sdb) {
+ rc = -ENOMEM;
+ goto allocate_sdbt_error;
+ }
+ *sdbt = sdb;
+ trailer = trailer_entry_ptr(*sdbt);
+ *trailer = SDB_TE_ALERT_REQ_MASK;
+ sdbt++;
+ }
+ num_sdb -= k;
+ sfb->num_sdb += k; /* count allocated sdb's */
+ tail = sdbt;
+ }
+
+ rc = 0;
+ if (tail)
+ *tail = sfb->sdbt + 1;
+ sfb->tail = (unsigned long) (void *)tail;
+
+allocate_sdbt_error:
+ if (rc)
+ free_sampling_buffer(sfb);
+ else
+ debug_sprintf_event(sfdbg, 4,
+ "alloc_sampling_buffer: tear=%0lx dear=%0lx\n",
+ sfb->sdbt, *(unsigned long *) sfb->sdbt);
+ return rc;
+}
+
+static int allocate_sdbt(struct cpu_hw_sf *cpuhw, const struct hw_perf_event *hwc)
+{
+ unsigned long n_sdb, freq;
+ unsigned long factor;
+
+ /* Calculate sampling buffers using 4K pages
+ *
+ * 1. Use frequency as input. The samping buffer is designed for
+ * a complete second. This can be adjusted through the "factor"
+ * variable.
+ * In any case, alloc_sampling_buffer() sets the Alert Request
+ * Control indicator to trigger measurement-alert to harvest
+ * sample-data-blocks (sdb).
+ *
+ * 2. Compute the number of sample-data-blocks and ensure a minimum
+ * of CPUM_SF_MIN_SDB. Also ensure the upper limit does not
+ * exceed CPUM_SF_MAX_SDB. See also the remarks for these
+ * symbolic constants.
+ *
+ * 3. Compute number of pages used for the sample-data-block-table
+ * and ensure a minimum of CPUM_SF_MIN_SDBT (at minimum one table
+ * to manage up to 511 sample-data-blocks).
+ */
+ freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc));
+ factor = 1;
+ n_sdb = DIV_ROUND_UP(freq, factor * ((PAGE_SIZE-64) / cpuhw->qsi.bsdes));
+ if (n_sdb < CPUM_SF_MIN_SDB)
+ n_sdb = CPUM_SF_MIN_SDB;
+
+ /* Return if there is already a sampling buffer allocated.
+ * XXX Remove this later and check number of available and
+ * required sdb's and, if necessary, increase the sampling buffer.
+ */
+ if (sf_buffer_available(cpuhw))
+ return 0;
+
+ debug_sprintf_event(sfdbg, 3,
+ "allocate_sdbt: rate=%lu f=%lu sdb=%lu/%i cpuhw=%p\n",
+ SAMPL_RATE(hwc), freq, n_sdb, CPUM_SF_MAX_SDB, cpuhw);
+
+ return alloc_sampling_buffer(&cpuhw->sfb,
+ min_t(unsigned long, n_sdb, CPUM_SF_MAX_SDB));
+}
+
+
+/* Number of perf events counting hardware events */
+static atomic_t num_events;
+/* Used to avoid races in calling reserve/release_cpumf_hardware */
+static DEFINE_MUTEX(pmc_reserve_mutex);
+
+/*
+ * sf_disable() - Switch off sampling facility
+ */
+static int sf_disable(void)
+{
+ struct hws_lsctl_request_block sreq;
+
+ memset(&sreq, 0, sizeof(sreq));
+ return lsctl(&sreq);
+}
+
+
+#define PMC_INIT 0
+#define PMC_RELEASE 1
+static void setup_pmc_cpu(void *flags)
+{
+ int err;
+ struct cpu_hw_sf *cpusf = &__get_cpu_var(cpu_hw_sf);
+
+ /* XXX Improve error handling and pass a flag in the *flags
+ * variable to indicate failures. Alternatively, ignore
+ * (print) errors here and let the PMU functions fail if
+ * the per-cpu PMU_F_RESERVED flag is not.
+ */
+ err = 0;
+ switch (*((int *) flags)) {
+ case PMC_INIT:
+ memset(cpusf, 0, sizeof(*cpusf));
+ err = qsi(&cpusf->qsi);
+ if (err)
+ break;
+ cpusf->flags |= PMU_F_RESERVED;
+ err = sf_disable();
+ if (err)
+ pr_err("Switching off the sampling facility failed "
+ "with rc=%i\n", err);
+ debug_sprintf_event(sfdbg, 5,
+ "setup_pmc_cpu: initialized: cpuhw=%p\n", cpusf);
+ break;
+ case PMC_RELEASE:
+ cpusf->flags &= ~PMU_F_RESERVED;
+ err = sf_disable();
+ if (err) {
+ pr_err("Switching off the sampling facility failed "
+ "with rc=%i\n", err);
+ } else {
+ if (cpusf->sfb.sdbt)
+ free_sampling_buffer(&cpusf->sfb);
+ }
+ debug_sprintf_event(sfdbg, 5,
+ "setup_pmc_cpu: released: cpuhw=%p\n", cpusf);
+ break;
+ }
+}
+
+static void release_pmc_hardware(void)
+{
+ int flags = PMC_RELEASE;
+
+ irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
+ on_each_cpu(setup_pmc_cpu, &flags, 1);
+}
+
+static int reserve_pmc_hardware(void)
+{
+ int flags = PMC_INIT;
+
+ on_each_cpu(setup_pmc_cpu, &flags, 1);
+ irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
+
+ return 0;
+}
+
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+ /* Release PMC if this is the last perf event */
+ if (!atomic_add_unless(&num_events, -1, 1)) {
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_dec_return(&num_events) == 0)
+ release_pmc_hardware();
+ mutex_unlock(&pmc_reserve_mutex);
+ }
+}
+
+static void hw_init_period(struct hw_perf_event *hwc, u64 period)
+{
+ hwc->sample_period = period;
+ hwc->last_period = hwc->sample_period;
+ local64_set(&hwc->period_left, hwc->sample_period);
+}
+
+static void hw_reset_registers(struct hw_perf_event *hwc,
+ unsigned long sdbt_origin)
+{
+ TEAR_REG(hwc) = sdbt_origin; /* (re)set to first sdb table */
+}
+
+static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si,
+ unsigned long rate)
+{
+ if (rate < si->min_sampl_rate)
+ return si->min_sampl_rate;
+ if (rate > si->max_sampl_rate)
+ return si->max_sampl_rate;
+ return rate;
+}
+
+static int __hw_perf_event_init(struct perf_event *event)
+{
+ struct cpu_hw_sf *cpuhw;
+ struct hws_qsi_info_block si;
+ struct perf_event_attr *attr = &event->attr;
+ struct hw_perf_event *hwc = &event->hw;
+ unsigned long rate;
+ int cpu, err;
+
+ /* Reserve CPU-measurement sampling facility */
+ err = 0;
+ if (!atomic_inc_not_zero(&num_events)) {
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_read(&num_events) == 0 && reserve_pmc_hardware())
+ err = -EBUSY;
+ else
+ atomic_inc(&num_events);
+ mutex_unlock(&pmc_reserve_mutex);
+ }
+ event->destroy = hw_perf_event_destroy;
+
+ if (err)
+ goto out;
+
+ /* Access per-CPU sampling information (query sampling info) */
+ /*
+ * The event->cpu value can be -1 to count on every CPU, for example,
+ * when attaching to a task. If this is specified, use the query
+ * sampling info from the current CPU, otherwise use event->cpu to
+ * retrieve the per-CPU information.
+ * Later, cpuhw indicates whether to allocate sampling buffers for a
+ * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL).
+ */
+ memset(&si, 0, sizeof(si));
+ cpuhw = NULL;
+ if (event->cpu == -1)
+ qsi(&si);
+ else {
+ /* Event is pinned to a particular CPU, retrieve the per-CPU
+ * sampling structure for accessing the CPU-specific QSI.
+ */
+ cpuhw = &per_cpu(cpu_hw_sf, event->cpu);
+ si = cpuhw->qsi;
+ }
+
+ /* Check sampling facility authorization and, if not authorized,
+ * fall back to other PMUs. It is safe to check any CPU because
+ * the authorization is identical for all configured CPUs.
+ */
+ if (!si.as) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ /* The sampling information (si) contains information about the
+ * min/max sampling intervals and the CPU speed. So calculate the
+ * correct sampling interval and avoid the whole period adjust
+ * feedback loop.
+ */
+ rate = 0;
+ if (attr->freq) {
+ rate = freq_to_sample_rate(&si, attr->sample_freq);
+ rate = hw_limit_rate(&si, rate);
+ attr->freq = 0;
+ attr->sample_period = rate;
+ } else {
+ /* The min/max sampling rates specifies the valid range
+ * of sample periods. If the specified sample period is
+ * out of range, limit the period to the range boundary.
+ */
+ rate = hw_limit_rate(&si, hwc->sample_period);
+
+ /* The perf core maintains a maximum sample rate that is
+ * configurable through the sysctl interface. Ensure the
+ * sampling rate does not exceed this value. This also helps
+ * to avoid throttling when pushing samples with
+ * perf_event_overflow().
+ */
+ if (sample_rate_to_freq(&si, rate) >
+ sysctl_perf_event_sample_rate) {
+ err = -EINVAL;
+ debug_sprintf_event(sfdbg, 1, "Sampling rate exceeds maximum perf sample rate\n");
+ goto out;
+ }
+ }
+ SAMPL_RATE(hwc) = rate;
+ hw_init_period(hwc, SAMPL_RATE(hwc));
+
+ /* Allocate the per-CPU sampling buffer using the CPU information
+ * from the event. If the event is not pinned to a particular
+ * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling
+ * buffers for each online CPU.
+ */
+ if (cpuhw)
+ /* Event is pinned to a particular CPU */
+ err = allocate_sdbt(cpuhw, hwc);
+ else {
+ /* Event is not pinned, allocate sampling buffer on
+ * each online CPU
+ */
+ for_each_online_cpu(cpu) {
+ cpuhw = &per_cpu(cpu_hw_sf, cpu);
+ err = allocate_sdbt(cpuhw, hwc);
+ if (err)
+ break;
+ }
+ }
+out:
+ return err;
+}
+
+static int cpumsf_pmu_event_init(struct perf_event *event)
+{
+ int err;
+
+ if (event->attr.type != PERF_TYPE_RAW)
+ return -ENOENT;
+
+ if (event->attr.config != PERF_EVENT_CPUM_SF)
+ return -ENOENT;
+
+ if (event->cpu >= nr_cpumask_bits ||
+ (event->cpu >= 0 && !cpu_online(event->cpu)))
+ return -ENODEV;
+
+ err = __hw_perf_event_init(event);
+ if (unlikely(err))
+ if (event->destroy)
+ event->destroy(event);
+ return err;
+}
+
+static void cpumsf_pmu_enable(struct pmu *pmu)
+{
+ struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
+ int err;
+
+ if (cpuhw->flags & PMU_F_ENABLED)
+ return;
+
+ if (cpuhw->flags & PMU_F_ERR_MASK)
+ return;
+
+ cpuhw->flags |= PMU_F_ENABLED;
+ barrier();
+
+ err = lsctl(&cpuhw->lsctl);
+ if (err) {
+ cpuhw->flags &= ~PMU_F_ENABLED;
+ pr_err("Loading sampling controls failed: op=%i err=%i\n",
+ 1, err);
+ return;
+ }
+
+ debug_sprintf_event(sfdbg, 6, "pmu_enable: es=%i cs=%i tear=%p dear=%p\n",
+ cpuhw->lsctl.es, cpuhw->lsctl.cs,
+ (void *) cpuhw->lsctl.tear, (void *) cpuhw->lsctl.dear);
+}
+
+static void cpumsf_pmu_disable(struct pmu *pmu)
+{
+ struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
+ struct hws_lsctl_request_block inactive;
+ struct hws_qsi_info_block si;
+ int err;
+
+ if (!(cpuhw->flags & PMU_F_ENABLED))
+ return;
+
+ if (cpuhw->flags & PMU_F_ERR_MASK)
+ return;
+
+ /* Switch off sampling activation control */
+ inactive = cpuhw->lsctl;
+ inactive.cs = 0;
+
+ err = lsctl(&inactive);
+ if (err) {
+ pr_err("Loading sampling controls failed: op=%i err=%i\n",
+ 2, err);
+ return;
+ }
+
+ /* Save state of TEAR and DEAR register contents */
+ if (!qsi(&si)) {
+ /* TEAR/DEAR values are valid only if the sampling facility is
+ * enabled. Note that cpumsf_pmu_disable() might be called even
+ * for a disabled sampling facility because cpumsf_pmu_enable()
+ * controls the enable/disable state.
+ */
+ if (si.es) {
+ cpuhw->lsctl.tear = si.tear;
+ cpuhw->lsctl.dear = si.dear;
+ }
+ } else
+ debug_sprintf_event(sfdbg, 3, "cpumsf_pmu_disable: "
+ "qsi() failed with err=%i\n", err);
+
+ cpuhw->flags &= ~PMU_F_ENABLED;
+}
+
+/* perf_push_sample() - Push samples to perf
+ * @event: The perf event
+ * @sample: Hardware sample data
+ *
+ * Use the hardware sample data to create perf event sample. The sample
+ * is the 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 perf_push_sample(struct perf_event *event,
+ struct hws_data_entry *sample)
+{
+ int overflow;
+ struct pt_regs regs;
+ struct perf_sample_data data;
+
+ /* Skip samples that are invalid or for which the instruction address
+ * is not predictable. For the latter, the wait-state bit is set.
+ */
+ if (sample->I || sample->W)
+ return 0;
+
+ perf_sample_data_init(&data, 0, event->hw.last_period);
+
+ memset(®s, 0, sizeof(regs));
+ regs.psw.addr = sample->ia;
+ if (sample->T)
+ regs.psw.mask |= PSW_MASK_DAT;
+ if (sample->W)
+ regs.psw.mask |= PSW_MASK_WAIT;
+ if (sample->P)
+ regs.psw.mask |= PSW_MASK_PSTATE;
+ switch (sample->AS) {
+ case 0x0:
+ regs.psw.mask |= PSW_ASC_PRIMARY;
+ break;
+ case 0x1:
+ regs.psw.mask |= PSW_ASC_ACCREG;
+ break;
+ case 0x2:
+ regs.psw.mask |= PSW_ASC_SECONDARY;
+ break;
+ case 0x3:
+ regs.psw.mask |= PSW_ASC_HOME;
+ break;
+ }
+
+ overflow = 0;
+ if (perf_event_overflow(event, &data, ®s)) {
+ overflow = 1;
+ event->pmu->stop(event, 0);
+ debug_sprintf_event(sfdbg, 4, "perf_push_sample: PMU stopped"
+ " because of an event overflow\n");
+ }
+ perf_event_update_userpage(event);
+
+ return overflow;
+}
+
+static void perf_event_count_update(struct perf_event *event, u64 count)
+{
+ local64_add(count, &event->count);
+}
+
+/* hw_collect_samples() - Walk through a sample-data-block and collect samples
+ * @event: The perf event
+ * @sdbt: Sample-data-block table
+ * @overflow: Event overflow counter
+ *
+ * Walks through a sample-data-block and collects hardware sample-data that is
+ * pushed to the perf event subsystem. The overflow reports the number of
+ * samples that has been discarded due to an event overflow.
+ */
+static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt,
+ unsigned long long *overflow)
+{
+ struct hws_data_entry *sample;
+ unsigned long *trailer;
+
+ trailer = trailer_entry_ptr(*sdbt);
+ sample = (struct hws_data_entry *) *sdbt;
+ while ((unsigned long *) sample < trailer) {
+ /* Check for an empty sample */
+ if (!sample->def)
+ break;
+
+ /* Update perf event period */
+ perf_event_count_update(event, SAMPL_RATE(&event->hw));
+
+ /* Check for basic sampling mode */
+ if (sample->def == 0x0001) {
+ /* If an event overflow occurred, the PMU is stopped to
+ * throttle event delivery. Remaining sample data is
+ * discarded.
+ */
+ if (!*overflow)
+ *overflow = perf_push_sample(event, sample);
+ else
+ /* Count discarded samples */
+ *overflow += 1;
+ } else
+ /* Sample slot is not yet written or other record */
+ debug_sprintf_event(sfdbg, 5, "hw_collect_samples: "
+ "Unknown sample data entry format:"
+ " %i\n", sample->def);
+
+ /* Reset sample slot and advance to next sample */
+ sample->def = 0;
+ sample++;
+ }
+}
+
+/* hw_perf_event_update() - Process sampling buffer
+ * @event: The perf event
+ * @flush_all: Flag to also flush partially filled sample-data-blocks
+ *
+ * Processes the sampling buffer and create perf event samples.
+ * The sampling buffer position are retrieved and saved in the TEAR_REG
+ * register of the specified perf event.
+ *
+ * Only full sample-data-blocks are processed. Specify the flash_all flag
+ * to also walk through partially filled sample-data-blocks.
+ *
+ */
+static void hw_perf_event_update(struct perf_event *event, int flush_all)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ struct hws_trailer_entry *te;
+ unsigned long *sdbt;
+ unsigned long long event_overflow, sampl_overflow;
+ int done;
+
+ sdbt = (unsigned long *) TEAR_REG(hwc);
+ done = event_overflow = sampl_overflow = 0;
+ while (!done) {
+ /* Get the trailer entry of the sample-data-block */
+ te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt);
+
+ /* Leave loop if no more work to do (block full indicator) */
+ if (!te->f) {
+ done = 1;
+ if (!flush_all)
+ break;
+ }
+
+ /* Check sample overflow count */
+ if (te->overflow) {
+ /* Increment sample overflow counter */
+ sampl_overflow += te->overflow;
+
+ /* XXX: If an sample overflow occurs, increase the
+ * sampling buffer. Set a "realloc" flag because
+ * the sampler must be re-enabled for changing
+ * the sample-data-block-table content.
+ */
+ }
+
+ /* Timestamps are valid for full sample-data-blocks only */
+ debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p "
+ "overflow=%llu timestamp=0x%llx\n",
+ sdbt, te->overflow,
+ (te->f) ? te->timestamp : 0ULL);
+
+ /* Collect all samples from a single sample-data-block and
+ * flag if an (perf) event overflow happened. If so, the PMU
+ * is stopped and remaining samples will be discarded.
+ */
+ hw_collect_samples(event, sdbt, &event_overflow);
+
+ /* Reset trailer */
+ xchg(&te->overflow, 0);
+ xchg((unsigned char *) te, 0x40);
+
+ /* Advance to next sample-data-block */
+ sdbt++;
+ if (is_link_entry(sdbt))
+ sdbt = get_next_sdbt(sdbt);
+
+ /* Update event hardware registers */
+ TEAR_REG(hwc) = (unsigned long) sdbt;
+
+ /* Stop processing sample-data if all samples of the current
+ * sample-data-block were flushed even if it was not full.
+ */
+ if (flush_all && done)
+ break;
+
+ /* If an event overflow happened, discard samples by
+ * processing any remaining sample-data-blocks.
+ */
+ if (event_overflow)
+ flush_all = 1;
+ }
+
+ if (sampl_overflow || event_overflow)
+ debug_sprintf_event(sfdbg, 4, "hw_perf_event_update: "
+ "overflow stats: sample=%llu event=%llu\n",
+ sampl_overflow, event_overflow);
+}
+
+static void cpumsf_pmu_read(struct perf_event *event)
+{
+ /* Nothing to do ... updates are interrupt-driven */
+}
+
+/* Activate sampling control.
+ * Next call of pmu_enable() starts sampling.
+ */
+static void cpumsf_pmu_start(struct perf_event *event, int flags)
+{
+ struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
+
+ if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
+ return;
+
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+
+ perf_pmu_disable(event->pmu);
+ event->hw.state = 0;
+ cpuhw->lsctl.cs = 1;
+ perf_pmu_enable(event->pmu);
+}
+
+/* Deactivate sampling control.
+ * Next call of pmu_enable() stops sampling.
+ */
+static void cpumsf_pmu_stop(struct perf_event *event, int flags)
+{
+ struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
+
+ if (event->hw.state & PERF_HES_STOPPED)
+ return;
+
+ perf_pmu_disable(event->pmu);
+ cpuhw->lsctl.cs = 0;
+ event->hw.state |= PERF_HES_STOPPED;
+
+ if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
+ hw_perf_event_update(event, 1);
+ event->hw.state |= PERF_HES_UPTODATE;
+ }
+ perf_pmu_enable(event->pmu);
+}
+
+static int cpumsf_pmu_add(struct perf_event *event, int flags)
+{
+ struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
+ int err;
+
+ if (cpuhw->flags & PMU_F_IN_USE)
+ return -EAGAIN;
+
+ if (!cpuhw->sfb.sdbt)
+ return -EINVAL;
+
+ err = 0;
+ perf_pmu_disable(event->pmu);
+
+ event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+ /* Set up sampling controls. Always program the sampling register
+ * using the SDB-table start. Reset TEAR_REG event hardware register
+ * that is used by hw_perf_event_update() to store the sampling buffer
+ * position after samples have been flushed.
+ */
+ cpuhw->lsctl.s = 0;
+ cpuhw->lsctl.h = 1;
+ cpuhw->lsctl.tear = cpuhw->sfb.sdbt;
+ cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt;
+ cpuhw->lsctl.interval = SAMPL_RATE(&event->hw);
+ hw_reset_registers(&event->hw, cpuhw->sfb.sdbt);
+
+ /* Ensure sampling functions are in the disabled state. If disabled,
+ * switch on sampling enable control. */
+ if (WARN_ON_ONCE(cpuhw->lsctl.es == 1)) {
+ err = -EAGAIN;
+ goto out;
+ }
+ cpuhw->lsctl.es = 1;
+
+ /* Set in_use flag and store event */
+ event->hw.idx = 0; /* only one sampling event per CPU supported */
+ cpuhw->event = event;
+ cpuhw->flags |= PMU_F_IN_USE;
+
+ if (flags & PERF_EF_START)
+ cpumsf_pmu_start(event, PERF_EF_RELOAD);
+out:
+ perf_event_update_userpage(event);
+ perf_pmu_enable(event->pmu);
+ return err;
+}
+
+static void cpumsf_pmu_del(struct perf_event *event, int flags)
+{
+ struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
+
+ perf_pmu_disable(event->pmu);
+ cpumsf_pmu_stop(event, PERF_EF_UPDATE);
+
+ cpuhw->lsctl.es = 0;
+ cpuhw->flags &= ~PMU_F_IN_USE;
+ cpuhw->event = NULL;
+
+ perf_event_update_userpage(event);
+ perf_pmu_enable(event->pmu);
+}
+
+static int cpumsf_pmu_event_idx(struct perf_event *event)
+{
+ return event->hw.idx;
+}
+
+CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF);
+
+static struct attribute *cpumsf_pmu_events_attr[] = {
+ CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC),
+ NULL,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-63");
+
+static struct attribute *cpumsf_pmu_format_attr[] = {
+ &format_attr_event.attr,
+ NULL,
+};
+
+static struct attribute_group cpumsf_pmu_events_group = {
+ .name = "events",
+ .attrs = cpumsf_pmu_events_attr,
+};
+static struct attribute_group cpumsf_pmu_format_group = {
+ .name = "format",
+ .attrs = cpumsf_pmu_format_attr,
+};
+static const struct attribute_group *cpumsf_pmu_attr_groups[] = {
+ &cpumsf_pmu_events_group,
+ &cpumsf_pmu_format_group,
+ NULL,
+};
+
+static struct pmu cpumf_sampling = {
+ .pmu_enable = cpumsf_pmu_enable,
+ .pmu_disable = cpumsf_pmu_disable,
+
+ .event_init = cpumsf_pmu_event_init,
+ .add = cpumsf_pmu_add,
+ .del = cpumsf_pmu_del,
+
+ .start = cpumsf_pmu_start,
+ .stop = cpumsf_pmu_stop,
+ .read = cpumsf_pmu_read,
+
+ .event_idx = cpumsf_pmu_event_idx,
+ .attr_groups = cpumsf_pmu_attr_groups,
+};
+
+static void cpumf_measurement_alert(struct ext_code ext_code,
+ unsigned int alert, unsigned long unused)
+{
+ struct cpu_hw_sf *cpuhw;
+
+ if (!(alert & CPU_MF_INT_SF_MASK))
+ return;
+ inc_irq_stat(IRQEXT_CMS);
+ cpuhw = &__get_cpu_var(cpu_hw_sf);
+
+ /* Measurement alerts are shared and might happen when the PMU
+ * is not reserved. Ignore these alerts in this case. */
+ if (!(cpuhw->flags & PMU_F_RESERVED))
+ return;
+
+ /* The processing below must take care of multiple alert events that
+ * might be indicated concurrently. */
+
+ /* Program alert request */
+ if (alert & CPU_MF_INT_SF_PRA) {
+ if (cpuhw->flags & PMU_F_IN_USE)
+ hw_perf_event_update(cpuhw->event, 0);
+ else
+ WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE));
+ }
+
+ /* Report measurement alerts only for non-PRA codes */
+ if (alert != CPU_MF_INT_SF_PRA)
+ debug_sprintf_event(sfdbg, 6, "measurement alert: 0x%x\n", alert);
+
+ /* Sampling authorization change request */
+ if (alert & CPU_MF_INT_SF_SACA)
+ qsi(&cpuhw->qsi);
+
+ /* Loss of sample data due to high-priority machine activities */
+ if (alert & CPU_MF_INT_SF_LSDA) {
+ pr_err("Sample data was lost\n");
+ cpuhw->flags |= PMU_F_ERR_LSDA;
+ sf_disable();
+ }
+
+ /* Invalid sampling buffer entry */
+ if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) {
+ pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n",
+ alert);
+ cpuhw->flags |= PMU_F_ERR_IBE;
+ sf_disable();
+ }
+}
+
+static int __cpuinit cpumf_pmu_notifier(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (long) hcpu;
+ int flags;
+
+ /* Ignore the notification if no events are scheduled on the PMU.
+ * This might be racy...
+ */
+ if (!atomic_read(&num_events))
+ return NOTIFY_OK;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ flags = PMC_INIT;
+ smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
+ break;
+ case CPU_DOWN_PREPARE:
+ flags = PMC_RELEASE;
+ smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
+ break;
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static int __init init_cpum_sampling_pmu(void)
+{
+ int err;
+
+ if (!cpum_sf_avail())
+ return -ENODEV;
+
+ sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80);
+ if (!sfdbg)
+ pr_err("Registering for s390dbf failed\n");
+ debug_register_view(sfdbg, &debug_sprintf_view);
+
+ err = register_external_interrupt(0x1407, cpumf_measurement_alert);
+ if (err) {
+ pr_err("Failed to register for CPU-measurement alerts\n");
+ goto out;
+ }
+
+ err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW);
+ if (err) {
+ pr_err("Failed to register cpum_sf pmu\n");
+ unregister_external_interrupt(0x1407, cpumf_measurement_alert);
+ goto out;
+ }
+ perf_cpu_notifier(cpumf_pmu_notifier);
+out:
+ return err;
+}
+arch_initcall(init_cpum_sampling_pmu);
projects / deliverable / linux.git / commitdiff
