summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/perf_event_fsl_emb.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/perf_event_fsl_emb.c')
-rw-r--r--arch/powerpc/kernel/perf_event_fsl_emb.c654
1 files changed, 654 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/perf_event_fsl_emb.c b/arch/powerpc/kernel/perf_event_fsl_emb.c
new file mode 100644
index 000000000000..369872f6cf78
--- /dev/null
+++ b/arch/powerpc/kernel/perf_event_fsl_emb.c
@@ -0,0 +1,654 @@
+/*
+ * Performance event support - Freescale Embedded Performance Monitor
+ *
+ * Copyright 2008-2009 Paul Mackerras, IBM Corporation.
+ * Copyright 2010 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/perf_event.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <asm/reg_fsl_emb.h>
+#include <asm/pmc.h>
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+#include <asm/ptrace.h>
+
+struct cpu_hw_events {
+ int n_events;
+ int disabled;
+ u8 pmcs_enabled;
+ struct perf_event *event[MAX_HWEVENTS];
+};
+static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
+
+static struct fsl_emb_pmu *ppmu;
+
+/* Number of perf_events counting hardware events */
+static atomic_t num_events;
+/* Used to avoid races in calling reserve/release_pmc_hardware */
+static DEFINE_MUTEX(pmc_reserve_mutex);
+
+/*
+ * If interrupts were soft-disabled when a PMU interrupt occurs, treat
+ * it as an NMI.
+ */
+static inline int perf_intr_is_nmi(struct pt_regs *regs)
+{
+#ifdef __powerpc64__
+ return !regs->softe;
+#else
+ return 0;
+#endif
+}
+
+static void perf_event_interrupt(struct pt_regs *regs);
+
+/*
+ * Read one performance monitor counter (PMC).
+ */
+static unsigned long read_pmc(int idx)
+{
+ unsigned long val;
+
+ switch (idx) {
+ case 0:
+ val = mfpmr(PMRN_PMC0);
+ break;
+ case 1:
+ val = mfpmr(PMRN_PMC1);
+ break;
+ case 2:
+ val = mfpmr(PMRN_PMC2);
+ break;
+ case 3:
+ val = mfpmr(PMRN_PMC3);
+ break;
+ default:
+ printk(KERN_ERR "oops trying to read PMC%d\n", idx);
+ val = 0;
+ }
+ return val;
+}
+
+/*
+ * Write one PMC.
+ */
+static void write_pmc(int idx, unsigned long val)
+{
+ switch (idx) {
+ case 0:
+ mtpmr(PMRN_PMC0, val);
+ break;
+ case 1:
+ mtpmr(PMRN_PMC1, val);
+ break;
+ case 2:
+ mtpmr(PMRN_PMC2, val);
+ break;
+ case 3:
+ mtpmr(PMRN_PMC3, val);
+ break;
+ default:
+ printk(KERN_ERR "oops trying to write PMC%d\n", idx);
+ }
+
+ isync();
+}
+
+/*
+ * Write one local control A register
+ */
+static void write_pmlca(int idx, unsigned long val)
+{
+ switch (idx) {
+ case 0:
+ mtpmr(PMRN_PMLCA0, val);
+ break;
+ case 1:
+ mtpmr(PMRN_PMLCA1, val);
+ break;
+ case 2:
+ mtpmr(PMRN_PMLCA2, val);
+ break;
+ case 3:
+ mtpmr(PMRN_PMLCA3, val);
+ break;
+ default:
+ printk(KERN_ERR "oops trying to write PMLCA%d\n", idx);
+ }
+
+ isync();
+}
+
+/*
+ * Write one local control B register
+ */
+static void write_pmlcb(int idx, unsigned long val)
+{
+ switch (idx) {
+ case 0:
+ mtpmr(PMRN_PMLCB0, val);
+ break;
+ case 1:
+ mtpmr(PMRN_PMLCB1, val);
+ break;
+ case 2:
+ mtpmr(PMRN_PMLCB2, val);
+ break;
+ case 3:
+ mtpmr(PMRN_PMLCB3, val);
+ break;
+ default:
+ printk(KERN_ERR "oops trying to write PMLCB%d\n", idx);
+ }
+
+ isync();
+}
+
+static void fsl_emb_pmu_read(struct perf_event *event)
+{
+ s64 val, delta, prev;
+
+ /*
+ * Performance monitor interrupts come even when interrupts
+ * are soft-disabled, as long as interrupts are hard-enabled.
+ * Therefore we treat them like NMIs.
+ */
+ do {
+ prev = atomic64_read(&event->hw.prev_count);
+ barrier();
+ val = read_pmc(event->hw.idx);
+ } while (atomic64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
+
+ /* The counters are only 32 bits wide */
+ delta = (val - prev) & 0xfffffffful;
+ atomic64_add(delta, &event->count);
+ atomic64_sub(delta, &event->hw.period_left);
+}
+
+/*
+ * Disable all events to prevent PMU interrupts and to allow
+ * events to be added or removed.
+ */
+void hw_perf_disable(void)
+{
+ struct cpu_hw_events *cpuhw;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ cpuhw = &__get_cpu_var(cpu_hw_events);
+
+ if (!cpuhw->disabled) {
+ cpuhw->disabled = 1;
+
+ /*
+ * Check if we ever enabled the PMU on this cpu.
+ */
+ if (!cpuhw->pmcs_enabled) {
+ ppc_enable_pmcs();
+ cpuhw->pmcs_enabled = 1;
+ }
+
+ if (atomic_read(&num_events)) {
+ /*
+ * Set the 'freeze all counters' bit, and disable
+ * interrupts. The barrier is to make sure the
+ * mtpmr has been executed and the PMU has frozen
+ * the events before we return.
+ */
+
+ mtpmr(PMRN_PMGC0, PMGC0_FAC);
+ isync();
+ }
+ }
+ local_irq_restore(flags);
+}
+
+/*
+ * Re-enable all events if disable == 0.
+ * If we were previously disabled and events were added, then
+ * put the new config on the PMU.
+ */
+void hw_perf_enable(void)
+{
+ struct cpu_hw_events *cpuhw;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ cpuhw = &__get_cpu_var(cpu_hw_events);
+ if (!cpuhw->disabled)
+ goto out;
+
+ cpuhw->disabled = 0;
+ ppc_set_pmu_inuse(cpuhw->n_events != 0);
+
+ if (cpuhw->n_events > 0) {
+ mtpmr(PMRN_PMGC0, PMGC0_PMIE | PMGC0_FCECE);
+ isync();
+ }
+
+ out:
+ local_irq_restore(flags);
+}
+
+static int collect_events(struct perf_event *group, int max_count,
+ struct perf_event *ctrs[])
+{
+ int n = 0;
+ struct perf_event *event;
+
+ if (!is_software_event(group)) {
+ if (n >= max_count)
+ return -1;
+ ctrs[n] = group;
+ n++;
+ }
+ list_for_each_entry(event, &group->sibling_list, group_entry) {
+ if (!is_software_event(event) &&
+ event->state != PERF_EVENT_STATE_OFF) {
+ if (n >= max_count)
+ return -1;
+ ctrs[n] = event;
+ n++;
+ }
+ }
+ return n;
+}
+
+/* perf must be disabled, context locked on entry */
+static int fsl_emb_pmu_enable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuhw;
+ int ret = -EAGAIN;
+ int num_counters = ppmu->n_counter;
+ u64 val;
+ int i;
+
+ cpuhw = &get_cpu_var(cpu_hw_events);
+
+ if (event->hw.config & FSL_EMB_EVENT_RESTRICTED)
+ num_counters = ppmu->n_restricted;
+
+ /*
+ * Allocate counters from top-down, so that restricted-capable
+ * counters are kept free as long as possible.
+ */
+ for (i = num_counters - 1; i >= 0; i--) {
+ if (cpuhw->event[i])
+ continue;
+
+ break;
+ }
+
+ if (i < 0)
+ goto out;
+
+ event->hw.idx = i;
+ cpuhw->event[i] = event;
+ ++cpuhw->n_events;
+
+ val = 0;
+ if (event->hw.sample_period) {
+ s64 left = atomic64_read(&event->hw.period_left);
+ if (left < 0x80000000L)
+ val = 0x80000000L - left;
+ }
+ atomic64_set(&event->hw.prev_count, val);
+ write_pmc(i, val);
+ perf_event_update_userpage(event);
+
+ write_pmlcb(i, event->hw.config >> 32);
+ write_pmlca(i, event->hw.config_base);
+
+ ret = 0;
+ out:
+ put_cpu_var(cpu_hw_events);
+ return ret;
+}
+
+/* perf must be disabled, context locked on entry */
+static void fsl_emb_pmu_disable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuhw;
+ int i = event->hw.idx;
+
+ if (i < 0)
+ goto out;
+
+ fsl_emb_pmu_read(event);
+
+ cpuhw = &get_cpu_var(cpu_hw_events);
+
+ WARN_ON(event != cpuhw->event[event->hw.idx]);
+
+ write_pmlca(i, 0);
+ write_pmlcb(i, 0);
+ write_pmc(i, 0);
+
+ cpuhw->event[i] = NULL;
+ event->hw.idx = -1;
+
+ /*
+ * TODO: if at least one restricted event exists, and we
+ * just freed up a non-restricted-capable counter, and
+ * there is a restricted-capable counter occupied by
+ * a non-restricted event, migrate that event to the
+ * vacated counter.
+ */
+
+ cpuhw->n_events--;
+
+ out:
+ put_cpu_var(cpu_hw_events);
+}
+
+/*
+ * Re-enable interrupts on a event after they were throttled
+ * because they were coming too fast.
+ *
+ * Context is locked on entry, but perf is not disabled.
+ */
+static void fsl_emb_pmu_unthrottle(struct perf_event *event)
+{
+ s64 val, left;
+ unsigned long flags;
+
+ if (event->hw.idx < 0 || !event->hw.sample_period)
+ return;
+ local_irq_save(flags);
+ perf_disable();
+ fsl_emb_pmu_read(event);
+ left = event->hw.sample_period;
+ event->hw.last_period = left;
+ val = 0;
+ if (left < 0x80000000L)
+ val = 0x80000000L - left;
+ write_pmc(event->hw.idx, val);
+ atomic64_set(&event->hw.prev_count, val);
+ atomic64_set(&event->hw.period_left, left);
+ perf_event_update_userpage(event);
+ perf_enable();
+ local_irq_restore(flags);
+}
+
+static struct pmu fsl_emb_pmu = {
+ .enable = fsl_emb_pmu_enable,
+ .disable = fsl_emb_pmu_disable,
+ .read = fsl_emb_pmu_read,
+ .unthrottle = fsl_emb_pmu_unthrottle,
+};
+
+/*
+ * Release the PMU if this 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)
+ release_pmc_hardware();
+ mutex_unlock(&pmc_reserve_mutex);
+ }
+}
+
+/*
+ * Translate a generic cache event_id config to a raw event_id code.
+ */
+static int hw_perf_cache_event(u64 config, u64 *eventp)
+{
+ unsigned long type, op, result;
+ int ev;
+
+ if (!ppmu->cache_events)
+ return -EINVAL;
+
+ /* unpack config */
+ type = config & 0xff;
+ op = (config >> 8) & 0xff;
+ result = (config >> 16) & 0xff;
+
+ if (type >= PERF_COUNT_HW_CACHE_MAX ||
+ op >= PERF_COUNT_HW_CACHE_OP_MAX ||
+ result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+ return -EINVAL;
+
+ ev = (*ppmu->cache_events)[type][op][result];
+ if (ev == 0)
+ return -EOPNOTSUPP;
+ if (ev == -1)
+ return -EINVAL;
+ *eventp = ev;
+ return 0;
+}
+
+const struct pmu *hw_perf_event_init(struct perf_event *event)
+{
+ u64 ev;
+ struct perf_event *events[MAX_HWEVENTS];
+ int n;
+ int err;
+ int num_restricted;
+ int i;
+
+ switch (event->attr.type) {
+ case PERF_TYPE_HARDWARE:
+ ev = event->attr.config;
+ if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0)
+ return ERR_PTR(-EOPNOTSUPP);
+ ev = ppmu->generic_events[ev];
+ break;
+
+ case PERF_TYPE_HW_CACHE:
+ err = hw_perf_cache_event(event->attr.config, &ev);
+ if (err)
+ return ERR_PTR(err);
+ break;
+
+ case PERF_TYPE_RAW:
+ ev = event->attr.config;
+ break;
+
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+
+ event->hw.config = ppmu->xlate_event(ev);
+ if (!(event->hw.config & FSL_EMB_EVENT_VALID))
+ return ERR_PTR(-EINVAL);
+
+ /*
+ * If this is in a group, check if it can go on with all the
+ * other hardware events in the group. We assume the event
+ * hasn't been linked into its leader's sibling list at this point.
+ */
+ n = 0;
+ if (event->group_leader != event) {
+ n = collect_events(event->group_leader,
+ ppmu->n_counter - 1, events);
+ if (n < 0)
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (event->hw.config & FSL_EMB_EVENT_RESTRICTED) {
+ num_restricted = 0;
+ for (i = 0; i < n; i++) {
+ if (events[i]->hw.config & FSL_EMB_EVENT_RESTRICTED)
+ num_restricted++;
+ }
+
+ if (num_restricted >= ppmu->n_restricted)
+ return ERR_PTR(-EINVAL);
+ }
+
+ event->hw.idx = -1;
+
+ event->hw.config_base = PMLCA_CE | PMLCA_FCM1 |
+ (u32)((ev << 16) & PMLCA_EVENT_MASK);
+
+ if (event->attr.exclude_user)
+ event->hw.config_base |= PMLCA_FCU;
+ if (event->attr.exclude_kernel)
+ event->hw.config_base |= PMLCA_FCS;
+ if (event->attr.exclude_idle)
+ return ERR_PTR(-ENOTSUPP);
+
+ event->hw.last_period = event->hw.sample_period;
+ atomic64_set(&event->hw.period_left, event->hw.last_period);
+
+ /*
+ * See if we need to reserve the PMU.
+ * If no events are currently in use, then we have to take a
+ * mutex to ensure that we don't race with another task doing
+ * reserve_pmc_hardware or release_pmc_hardware.
+ */
+ err = 0;
+ if (!atomic_inc_not_zero(&num_events)) {
+ mutex_lock(&pmc_reserve_mutex);
+ if (atomic_read(&num_events) == 0 &&
+ reserve_pmc_hardware(perf_event_interrupt))
+ err = -EBUSY;
+ else
+ atomic_inc(&num_events);
+ mutex_unlock(&pmc_reserve_mutex);
+
+ mtpmr(PMRN_PMGC0, PMGC0_FAC);
+ isync();
+ }
+ event->destroy = hw_perf_event_destroy;
+
+ if (err)
+ return ERR_PTR(err);
+ return &fsl_emb_pmu;
+}
+
+/*
+ * A counter has overflowed; update its count and record
+ * things if requested. Note that interrupts are hard-disabled
+ * here so there is no possibility of being interrupted.
+ */
+static void record_and_restart(struct perf_event *event, unsigned long val,
+ struct pt_regs *regs, int nmi)
+{
+ u64 period = event->hw.sample_period;
+ s64 prev, delta, left;
+ int record = 0;
+
+ /* we don't have to worry about interrupts here */
+ prev = atomic64_read(&event->hw.prev_count);
+ delta = (val - prev) & 0xfffffffful;
+ atomic64_add(delta, &event->count);
+
+ /*
+ * See if the total period for this event has expired,
+ * and update for the next period.
+ */
+ val = 0;
+ left = atomic64_read(&event->hw.period_left) - delta;
+ if (period) {
+ if (left <= 0) {
+ left += period;
+ if (left <= 0)
+ left = period;
+ record = 1;
+ }
+ if (left < 0x80000000LL)
+ val = 0x80000000LL - left;
+ }
+
+ /*
+ * Finally record data if requested.
+ */
+ if (record) {
+ struct perf_sample_data data = {
+ .period = event->hw.last_period,
+ };
+
+ if (perf_event_overflow(event, nmi, &data, regs)) {
+ /*
+ * Interrupts are coming too fast - throttle them
+ * by setting the event to 0, so it will be
+ * at least 2^30 cycles until the next interrupt
+ * (assuming each event counts at most 2 counts
+ * per cycle).
+ */
+ val = 0;
+ left = ~0ULL >> 1;
+ }
+ }
+
+ write_pmc(event->hw.idx, val);
+ atomic64_set(&event->hw.prev_count, val);
+ atomic64_set(&event->hw.period_left, left);
+ perf_event_update_userpage(event);
+}
+
+static void perf_event_interrupt(struct pt_regs *regs)
+{
+ int i;
+ struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
+ struct perf_event *event;
+ unsigned long val;
+ int found = 0;
+ int nmi;
+
+ nmi = perf_intr_is_nmi(regs);
+ if (nmi)
+ nmi_enter();
+ else
+ irq_enter();
+
+ for (i = 0; i < ppmu->n_counter; ++i) {
+ event = cpuhw->event[i];
+
+ val = read_pmc(i);
+ if ((int)val < 0) {
+ if (event) {
+ /* event has overflowed */
+ found = 1;
+ record_and_restart(event, val, regs, nmi);
+ } else {
+ /*
+ * Disabled counter is negative,
+ * reset it just in case.
+ */
+ write_pmc(i, 0);
+ }
+ }
+ }
+
+ /* PMM will keep counters frozen until we return from the interrupt. */
+ mtmsr(mfmsr() | MSR_PMM);
+ mtpmr(PMRN_PMGC0, PMGC0_PMIE | PMGC0_FCECE);
+ isync();
+
+ if (nmi)
+ nmi_exit();
+ else
+ irq_exit();
+}
+
+void hw_perf_event_setup(int cpu)
+{
+ struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
+
+ memset(cpuhw, 0, sizeof(*cpuhw));
+}
+
+int register_fsl_emb_pmu(struct fsl_emb_pmu *pmu)
+{
+ if (ppmu)
+ return -EBUSY; /* something's already registered */
+
+ ppmu = pmu;
+ pr_info("%s performance monitor hardware support registered\n",
+ pmu->name);
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-01 04:42:50 +0000