perf: Register PMU implementations

Simple registration interface for struct pmu, this provides the
infrastructure for removing all the weak functions.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Michael Cree <mcree@orcon.net.nz>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 290 insertions, 298 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index fb46fd13f31f..288ce43de57c 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -31,7 +31,6 @@
 #include <linux/kernel_stat.h>
 #include <linux/perf_event.h>
 #include <linux/ftrace_event.h>
-#include <linux/hw_breakpoint.h>
 
 #include <asm/irq_regs.h>
 
@@ -72,14 +71,6 @@ static atomic64_t perf_event_id;
  */
 static DEFINE_SPINLOCK(perf_resource_lock);
 
-/*
- * Architecture provided APIs - weak aliases:
- */
-extern __weak struct pmu *hw_perf_event_init(struct perf_event *event)
-{
-        return NULL;
-}
-
 void __weak hw_perf_disable(void)               { barrier(); }
 void __weak hw_perf_enable(void)                { barrier(); }
 
@@ -4501,182 +4492,6 @@ static int perf_swevent_int(struct perf_event *event)
         return 0;
 }
 
-static struct pmu perf_ops_generic = {
-        .enable         = perf_swevent_enable,
-        .disable        = perf_swevent_disable,
-        .start          = perf_swevent_int,
-        .stop           = perf_swevent_void,
-        .read           = perf_swevent_read,
-        .unthrottle     = perf_swevent_void, /* hwc->interrupts already reset */
-};
-
-/*
- * hrtimer based swevent callback
- */
-
-static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
-{
-        enum hrtimer_restart ret = HRTIMER_RESTART;
-        struct perf_sample_data data;
-        struct pt_regs *regs;
-        struct perf_event *event;
-        u64 period;
-
-        event = container_of(hrtimer, struct perf_event, hw.hrtimer);
-        event->pmu->read(event);
-
-        perf_sample_data_init(&data, 0);
-        data.period = event->hw.last_period;
-        regs = get_irq_regs();
-
-        if (regs && !perf_exclude_event(event, regs)) {
-                if (!(event->attr.exclude_idle && current->pid == 0))
-                        if (perf_event_overflow(event, 0, &data, regs))
-                                ret = HRTIMER_NORESTART;
-        }
-
-        period = max_t(u64, 10000, event->hw.sample_period);
-        hrtimer_forward_now(hrtimer, ns_to_ktime(period));
-
-        return ret;
-}
-
-static void perf_swevent_start_hrtimer(struct perf_event *event)
-{
-        struct hw_perf_event *hwc = &event->hw;
-
-        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-        hwc->hrtimer.function = perf_swevent_hrtimer;
-        if (hwc->sample_period) {
-                u64 period;
-
-                if (hwc->remaining) {
-                        if (hwc->remaining < 0)
-                                period = 10000;
-                        else
-                                period = hwc->remaining;
-                        hwc->remaining = 0;
-                } else {
-                        period = max_t(u64, 10000, hwc->sample_period);
-                }
-                __hrtimer_start_range_ns(&hwc->hrtimer,
-                                ns_to_ktime(period), 0,
-                                HRTIMER_MODE_REL, 0);
-        }
-}
-
-static void perf_swevent_cancel_hrtimer(struct perf_event *event)
-{
-        struct hw_perf_event *hwc = &event->hw;
-
-        if (hwc->sample_period) {
-                ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
-                hwc->remaining = ktime_to_ns(remaining);
-
-                hrtimer_cancel(&hwc->hrtimer);
-        }
-}
-
-/*
- * Software event: cpu wall time clock
- */
-
-static void cpu_clock_perf_event_update(struct perf_event *event)
-{
-        int cpu = raw_smp_processor_id();
-        s64 prev;
-        u64 now;
-
-        now = cpu_clock(cpu);
-        prev = local64_xchg(&event->hw.prev_count, now);
-        local64_add(now - prev, &event->count);
-}
-
-static int cpu_clock_perf_event_enable(struct perf_event *event)
-{
-        struct hw_perf_event *hwc = &event->hw;
-        int cpu = raw_smp_processor_id();
-
-        local64_set(&hwc->prev_count, cpu_clock(cpu));
-        perf_swevent_start_hrtimer(event);
-
-        return 0;
-}
-
-static void cpu_clock_perf_event_disable(struct perf_event *event)
-{
-        perf_swevent_cancel_hrtimer(event);
-        cpu_clock_perf_event_update(event);
-}
-
-static void cpu_clock_perf_event_read(struct perf_event *event)
-{
-        cpu_clock_perf_event_update(event);
-}
-
-static struct pmu perf_ops_cpu_clock = {
-        .enable         = cpu_clock_perf_event_enable,
-        .disable        = cpu_clock_perf_event_disable,
-        .read           = cpu_clock_perf_event_read,
-};
-
-/*
- * Software event: task time clock
- */
-
-static void task_clock_perf_event_update(struct perf_event *event, u64 now)
-{
-        u64 prev;
-        s64 delta;
-
-        prev = local64_xchg(&event->hw.prev_count, now);
-        delta = now - prev;
-        local64_add(delta, &event->count);
-}
-
-static int task_clock_perf_event_enable(struct perf_event *event)
-{
-        struct hw_perf_event *hwc = &event->hw;
-        u64 now;
-
-        now = event->ctx->time;
-
-        local64_set(&hwc->prev_count, now);
-
-        perf_swevent_start_hrtimer(event);
-
-        return 0;
-}
-
-static void task_clock_perf_event_disable(struct perf_event *event)
-{
-        perf_swevent_cancel_hrtimer(event);
-        task_clock_perf_event_update(event, event->ctx->time);
-
-}
-
-static void task_clock_perf_event_read(struct perf_event *event)
-{
-        u64 time;
-
-        if (!in_nmi()) {
-                update_context_time(event->ctx);
-                time = event->ctx->time;
-        } else {
-                u64 now = perf_clock();
-                u64 delta = now - event->ctx->timestamp;
-                time = event->ctx->time + delta;
-        }
-
-        task_clock_perf_event_update(event, time);
-}
-
-static struct pmu perf_ops_task_clock = {
-        .enable         = task_clock_perf_event_enable,
-        .disable        = task_clock_perf_event_disable,
-        .read           = task_clock_perf_event_read,
-};
-
 /* Deref the hlist from the update side */
 static inline struct swevent_hlist *
 swevent_hlist_deref(struct perf_cpu_context *cpuctx)
@@ -4783,17 +4598,63 @@ static int swevent_hlist_get(struct perf_event *event)
         return err;
 }
 
-#ifdef CONFIG_EVENT_TRACING
+atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
 
-static struct pmu perf_ops_tracepoint = {
-        .enable         = perf_trace_enable,
-        .disable        = perf_trace_disable,
+static void sw_perf_event_destroy(struct perf_event *event)
+{
+        u64 event_id = event->attr.config;
+
+        WARN_ON(event->parent);
+
+        atomic_dec(&perf_swevent_enabled[event_id]);
+        swevent_hlist_put(event);
+}
+
+static int perf_swevent_init(struct perf_event *event)
+{
+        int event_id = event->attr.config;
+
+        if (event->attr.type != PERF_TYPE_SOFTWARE)
+                return -ENOENT;
+
+        switch (event_id) {
+        case PERF_COUNT_SW_CPU_CLOCK:
+        case PERF_COUNT_SW_TASK_CLOCK:
+                return -ENOENT;
+
+        default:
+                break;
+        }
+
+        if (event_id > PERF_COUNT_SW_MAX)
+                return -ENOENT;
+
+        if (!event->parent) {
+                int err;
+
+                err = swevent_hlist_get(event);
+                if (err)
+                        return err;
+
+                atomic_inc(&perf_swevent_enabled[event_id]);
+                event->destroy = sw_perf_event_destroy;
+        }
+
+        return 0;
+}
+
+static struct pmu perf_swevent = {
+        .event_init     = perf_swevent_init,
+        .enable         = perf_swevent_enable,
+        .disable        = perf_swevent_disable,
         .start          = perf_swevent_int,
         .stop           = perf_swevent_void,
         .read           = perf_swevent_read,
-        .unthrottle     = perf_swevent_void,
+        .unthrottle     = perf_swevent_void, /* hwc->interrupts already reset */
 };
 
+#ifdef CONFIG_EVENT_TRACING
+
 static int perf_tp_filter_match(struct perf_event *event,
                                 struct perf_sample_data *data)
 {
@@ -4849,10 +4710,13 @@ static void tp_perf_event_destroy(struct perf_event *event)
         perf_trace_destroy(event);
 }
 
-static struct pmu *tp_perf_event_init(struct perf_event *event)
+static int perf_tp_event_init(struct perf_event *event)
 {
         int err;
 
+        if (event->attr.type != PERF_TYPE_TRACEPOINT)
+                return -ENOENT;
+
         /*
          * Raw tracepoint data is a severe data leak, only allow root to
          * have these.
@@ -4860,15 +4724,30 @@ static struct pmu *tp_perf_event_init(struct perf_event *event)
         if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
                         perf_paranoid_tracepoint_raw() &&
                         !capable(CAP_SYS_ADMIN))
-                return ERR_PTR(-EPERM);
+                return -EPERM;
 
         err = perf_trace_init(event);
         if (err)
-                return NULL;
+                return err;
 
         event->destroy = tp_perf_event_destroy;
 
-        return &perf_ops_tracepoint;
+        return 0;
+}
+
+static struct pmu perf_tracepoint = {
+        .event_init     = perf_tp_event_init,
+        .enable         = perf_trace_enable,
+        .disable        = perf_trace_disable,
+        .start          = perf_swevent_int,
+        .stop           = perf_swevent_void,
+        .read           = perf_swevent_read,
+        .unthrottle     = perf_swevent_void,
+};
+
+static inline void perf_tp_register(void)
+{
+        perf_pmu_register(&perf_tracepoint);
 }
 
 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
@@ -4896,9 +4775,8 @@ static void perf_event_free_filter(struct perf_event *event)
 
 #else
 
-static struct pmu *tp_perf_event_init(struct perf_event *event)
+static inline void perf_tp_register(void)
 {
-        return NULL;
 }
 
 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
@@ -4913,105 +4791,247 @@ static void perf_event_free_filter(struct perf_event *event)
 #endif /* CONFIG_EVENT_TRACING */
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
-static void bp_perf_event_destroy(struct perf_event *event)
+void perf_bp_event(struct perf_event *bp, void *data)
 {
-        release_bp_slot(event);
+        struct perf_sample_data sample;
+        struct pt_regs *regs = data;
+
+        perf_sample_data_init(&sample, bp->attr.bp_addr);
+
+        if (!perf_exclude_event(bp, regs))
+                perf_swevent_add(bp, 1, 1, &sample, regs);
 }
+#endif
+
+/*
+ * hrtimer based swevent callback
+ */
 
-static struct pmu *bp_perf_event_init(struct perf_event *bp)
+static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 {
-        int err;
+        enum hrtimer_restart ret = HRTIMER_RESTART;
+        struct perf_sample_data data;
+        struct pt_regs *regs;
+        struct perf_event *event;
+        u64 period;
 
-        err = register_perf_hw_breakpoint(bp);
-        if (err)
-                return ERR_PTR(err);
+        event = container_of(hrtimer, struct perf_event, hw.hrtimer);
+        event->pmu->read(event);
+
+        perf_sample_data_init(&data, 0);
+        data.period = event->hw.last_period;
+        regs = get_irq_regs();
+
+        if (regs && !perf_exclude_event(event, regs)) {
+                if (!(event->attr.exclude_idle && current->pid == 0))
+                        if (perf_event_overflow(event, 0, &data, regs))
+                                ret = HRTIMER_NORESTART;
+        }
 
-        bp->destroy = bp_perf_event_destroy;
+        period = max_t(u64, 10000, event->hw.sample_period);
+        hrtimer_forward_now(hrtimer, ns_to_ktime(period));
 
-        return &perf_ops_bp;
+        return ret;
 }
 
-void perf_bp_event(struct perf_event *bp, void *data)
+static void perf_swevent_start_hrtimer(struct perf_event *event)
 {
-        struct perf_sample_data sample;
-        struct pt_regs *regs = data;
+        struct hw_perf_event *hwc = &event->hw;
 
-        perf_sample_data_init(&sample, bp->attr.bp_addr);
+        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+        hwc->hrtimer.function = perf_swevent_hrtimer;
+        if (hwc->sample_period) {
+                u64 period;
 
-        if (!perf_exclude_event(bp, regs))
-                perf_swevent_add(bp, 1, 1, &sample, regs);
+                if (hwc->remaining) {
+                        if (hwc->remaining < 0)
+                                period = 10000;
+                        else
+                                period = hwc->remaining;
+                        hwc->remaining = 0;
+                } else {
+                        period = max_t(u64, 10000, hwc->sample_period);
+                }
+                __hrtimer_start_range_ns(&hwc->hrtimer,
+                                ns_to_ktime(period), 0,
+                                HRTIMER_MODE_REL, 0);
+        }
 }
-#else
-static struct pmu *bp_perf_event_init(struct perf_event *bp)
+
+static void perf_swevent_cancel_hrtimer(struct perf_event *event)
 {
-        return NULL;
+        struct hw_perf_event *hwc = &event->hw;
+
+        if (hwc->sample_period) {
+                ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
+                hwc->remaining = ktime_to_ns(remaining);
+
+                hrtimer_cancel(&hwc->hrtimer);
+        }
 }
 
-void perf_bp_event(struct perf_event *bp, void *regs)
+/*
+ * Software event: cpu wall time clock
+ */
+
+static void cpu_clock_event_update(struct perf_event *event)
 {
+        int cpu = raw_smp_processor_id();
+        s64 prev;
+        u64 now;
+
+        now = cpu_clock(cpu);
+        prev = local64_xchg(&event->hw.prev_count, now);
+        local64_add(now - prev, &event->count);
 }
-#endif
 
-atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
+static int cpu_clock_event_enable(struct perf_event *event)
+{
+        struct hw_perf_event *hwc = &event->hw;
+        int cpu = raw_smp_processor_id();
 
-static void sw_perf_event_destroy(struct perf_event *event)
+        local64_set(&hwc->prev_count, cpu_clock(cpu));
+        perf_swevent_start_hrtimer(event);
+
+        return 0;
+}
+
+static void cpu_clock_event_disable(struct perf_event *event)
 {
-        u64 event_id = event->attr.config;
+        perf_swevent_cancel_hrtimer(event);
+        cpu_clock_event_update(event);
+}
 
-        WARN_ON(event->parent);
+static void cpu_clock_event_read(struct perf_event *event)
+{
+        cpu_clock_event_update(event);
+}
 
-        atomic_dec(&perf_swevent_enabled[event_id]);
-        swevent_hlist_put(event);
+static int cpu_clock_event_init(struct perf_event *event)
+{
+        if (event->attr.type != PERF_TYPE_SOFTWARE)
+                return -ENOENT;
+
+        if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
+                return -ENOENT;
+
+        return 0;
 }
 
-static struct pmu *sw_perf_event_init(struct perf_event *event)
+static struct pmu perf_cpu_clock = {
+        .event_init     = cpu_clock_event_init,
+        .enable         = cpu_clock_event_enable,
+        .disable        = cpu_clock_event_disable,
+        .read           = cpu_clock_event_read,
+};
+
+/*
+ * Software event: task time clock
+ */
+
+static void task_clock_event_update(struct perf_event *event, u64 now)
 {
-        struct pmu *pmu = NULL;
-        u64 event_id = event->attr.config;
+        u64 prev;
+        s64 delta;
 
-        /*
-         * Software events (currently) can't in general distinguish
-         * between user, kernel and hypervisor events.
-         * However, context switches and cpu migrations are considered
-         * to be kernel events, and page faults are never hypervisor
-         * events.
-         */
-        switch (event_id) {
-        case PERF_COUNT_SW_CPU_CLOCK:
-                pmu = &perf_ops_cpu_clock;
+        prev = local64_xchg(&event->hw.prev_count, now);
+        delta = now - prev;
+        local64_add(delta, &event->count);
+}
 
-                break;
-        case PERF_COUNT_SW_TASK_CLOCK:
-                /*
-                 * If the user instantiates this as a per-cpu event,
-                 * use the cpu_clock event instead.
-                 */
-                if (event->ctx->task)
-                        pmu = &perf_ops_task_clock;
-                else
-                        pmu = &perf_ops_cpu_clock;
+static int task_clock_event_enable(struct perf_event *event)
+{
+        struct hw_perf_event *hwc = &event->hw;
+        u64 now;
 
-                break;
-        case PERF_COUNT_SW_PAGE_FAULTS:
-        case PERF_COUNT_SW_PAGE_FAULTS_MIN:
-        case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
-        case PERF_COUNT_SW_CONTEXT_SWITCHES:
-        case PERF_COUNT_SW_CPU_MIGRATIONS:
-        case PERF_COUNT_SW_ALIGNMENT_FAULTS:
-        case PERF_COUNT_SW_EMULATION_FAULTS:
-                if (!event->parent) {
-                        int err;
-
-                        err = swevent_hlist_get(event);
-                        if (err)
-                                return ERR_PTR(err);
+        now = event->ctx->time;
 
-                        atomic_inc(&perf_swevent_enabled[event_id]);
-                        event->destroy = sw_perf_event_destroy;
+        local64_set(&hwc->prev_count, now);
+
+        perf_swevent_start_hrtimer(event);
+
+        return 0;
+}
+
+static void task_clock_event_disable(struct perf_event *event)
+{
+        perf_swevent_cancel_hrtimer(event);
+        task_clock_event_update(event, event->ctx->time);
+
+}
+
+static void task_clock_event_read(struct perf_event *event)
+{
+        u64 time;
+
+        if (!in_nmi()) {
+                update_context_time(event->ctx);
+                time = event->ctx->time;
+        } else {
+                u64 now = perf_clock();
+                u64 delta = now - event->ctx->timestamp;
+                time = event->ctx->time + delta;
+        }
+
+        task_clock_event_update(event, time);
+}
+
+static int task_clock_event_init(struct perf_event *event)
+{
+        if (event->attr.type != PERF_TYPE_SOFTWARE)
+                return -ENOENT;
+
+        if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
+                return -ENOENT;
+
+        return 0;
+}
+
+static struct pmu perf_task_clock = {
+        .event_init     = task_clock_event_init,
+        .enable         = task_clock_event_enable,
+        .disable        = task_clock_event_disable,
+        .read           = task_clock_event_read,
+};
+
+static LIST_HEAD(pmus);
+static DEFINE_MUTEX(pmus_lock);
+static struct srcu_struct pmus_srcu;
+
+int perf_pmu_register(struct pmu *pmu)
+{
+        mutex_lock(&pmus_lock);
+        list_add_rcu(&pmu->entry, &pmus);
+        mutex_unlock(&pmus_lock);
+
+        return 0;
+}
+
+void perf_pmu_unregister(struct pmu *pmu)
+{
+        mutex_lock(&pmus_lock);
+        list_del_rcu(&pmu->entry);
+        mutex_unlock(&pmus_lock);
+
+        synchronize_srcu(&pmus_srcu);
+}
+
+struct pmu *perf_init_event(struct perf_event *event)
+{
+        struct pmu *pmu = NULL;
+        int idx;
+
+        idx = srcu_read_lock(&pmus_srcu);
+        list_for_each_entry_rcu(pmu, &pmus, entry) {
+                int ret = pmu->event_init(event);
+                if (!ret)
+                        break;
+                if (ret != -ENOENT) {
+                        pmu = ERR_PTR(ret);
+                        break;
                 }
-                pmu = &perf_ops_generic;
-                break;
         }
+        srcu_read_unlock(&pmus_srcu, idx);
 
         return pmu;
 }
@@ -5092,29 +5112,8 @@ perf_event_alloc(struct perf_event_attr *attr,
         if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
                 goto done;
 
-        switch (attr->type) {
-        case PERF_TYPE_RAW:
-        case PERF_TYPE_HARDWARE:
-        case PERF_TYPE_HW_CACHE:
-                pmu = hw_perf_event_init(event);
-                break;
-
-        case PERF_TYPE_SOFTWARE:
-                pmu = sw_perf_event_init(event);
-                break;
-
-        case PERF_TYPE_TRACEPOINT:
-                pmu = tp_perf_event_init(event);
-                break;
+        pmu = perf_init_event(event);
 
-        case PERF_TYPE_BREAKPOINT:
-                pmu = bp_perf_event_init(event);
-                break;
-
-
-        default:
-                break;
-        }
 done:
         err = 0;
         if (!pmu)
@@ -5979,22 +5978,15 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
         return NOTIFY_OK;
 }
 
-/*
- * This has to have a higher priority than migration_notifier in sched.c.
- */
-static struct notifier_block __cpuinitdata perf_cpu_nb = {
-        .notifier_call          = perf_cpu_notify,
-        .priority               = 20,
-};
-
 void __init perf_event_init(void)
 {
         perf_event_init_all_cpus();
-        perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
-                        (void *)(long)smp_processor_id());
-        perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
-                        (void *)(long)smp_processor_id());
-        register_cpu_notifier(&perf_cpu_nb);
+        init_srcu_struct(&pmus_srcu);
+        perf_pmu_register(&perf_swevent);
+        perf_pmu_register(&perf_cpu_clock);
+        perf_pmu_register(&perf_task_clock);
+        perf_tp_register();
+        perf_cpu_notifier(perf_cpu_notify);
 }
 
 static ssize_t perf_show_reserve_percpu(struct sysdev_class *class,