MIPS, Perf-events: Work with the new PMU interface

This is the MIPS part of the following commits by Peter Zijlstra:

- a4eaf7f14675cb512d69f0c928055e73d0c6d252
    perf: Rework the PMU methods

    Replace pmu::{enable,disable,start,stop,unthrottle} with
    pmu::{add,del,start,stop}, all of which take a flags argument.

    The new interface extends the capability to stop a counter while
    keeping it scheduled on the PMU. We replace the throttled state with
    the generic stopped state.

    This also allows us to efficiently stop/start counters over certain
    code paths (like IRQ handlers).

    It also allows scheduling a counter without it starting, allowing for
    a generic frozen state (useful for rotating stopped counters).

    The stopped state is implemented in two different ways, depending on
    how the architecture implemented the throttled state:

     1) We disable the counter:
        a) the pmu has per-counter enable bits, we flip that
        b) we program a NOP event, preserving the counter state

     2) We store the counter state and ignore all read/overflow events

For MIPSXX, the stopped state is implemented in the way of 1.b as above.

- 33696fc0d141bbbcb12f75b69608ea83282e3117
    perf: Per PMU disable

    Changes perf_disable() into perf_pmu_disable().

- 24cd7f54a0d47e1d5b3de29e2456bfbd2d8447b7
    perf: Reduce perf_disable() usage

    Since the current perf_disable() usage is only an optimization,
    remove it for now. This eases the removal of the __weak
    hw_perf_enable() interface.

- b0a873ebbf87bf38bf70b5e39a7cadc96099fa13
    perf: Register PMU implementations

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

- 51b0fe39549a04858001922919ab355dee9bdfcf
    perf: Deconstify struct pmu

    sed -ie 's/const struct pmu\>/struct pmu/g' `git grep -l "const struct pmu\>"`

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2012/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 158 insertions, 119 deletions

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 2b7f3f703b83..1ee44a3f9718 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -161,41 +161,6 @@ mipspmu_event_set_period(struct perf_event *event,
         return ret;
 }
 
-static int mipspmu_enable(struct perf_event *event)
-{
-        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
-        struct hw_perf_event *hwc = &event->hw;
-        int idx;
-        int err = 0;
-
-        /* To look for a free counter for this event. */
-        idx = mipspmu->alloc_counter(cpuc, hwc);
-        if (idx < 0) {
-                err = idx;
-                goto out;
-        }
-
-        /*
-         * If there is an event in the counter we are going to use then
-         * make sure it is disabled.
-         */
-        event->hw.idx = idx;
-        mipspmu->disable_event(idx);
-        cpuc->events[idx] = event;
-
-        /* Set the period for the event. */
-        mipspmu_event_set_period(event, hwc, idx);
-
-        /* Enable the event. */
-        mipspmu->enable_event(hwc, idx);
-
-        /* Propagate our changes to the userspace mapping. */
-        perf_event_update_userpage(event);
-
-out:
-        return err;
-}
-
 static void mipspmu_event_update(struct perf_event *event,
                         struct hw_perf_event *hwc,
                         int idx)
@@ -231,32 +196,90 @@ again:
         return;
 }
 
-static void mipspmu_disable(struct perf_event *event)
+static void mipspmu_start(struct perf_event *event, int flags)
+{
+        struct hw_perf_event *hwc = &event->hw;
+
+        if (!mipspmu)
+                return;
+
+        if (flags & PERF_EF_RELOAD)
+                WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+
+        hwc->state = 0;
+
+        /* Set the period for the event. */
+        mipspmu_event_set_period(event, hwc, hwc->idx);
+
+        /* Enable the event. */
+        mipspmu->enable_event(hwc, hwc->idx);
+}
+
+static void mipspmu_stop(struct perf_event *event, int flags)
+{
+        struct hw_perf_event *hwc = &event->hw;
+
+        if (!mipspmu)
+                return;
+
+        if (!(hwc->state & PERF_HES_STOPPED)) {
+                /* We are working on a local event. */
+                mipspmu->disable_event(hwc->idx);
+                barrier();
+                mipspmu_event_update(event, hwc, hwc->idx);
+                hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+        }
+}
+
+static int mipspmu_add(struct perf_event *event, int flags)
 {
         struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
         struct hw_perf_event *hwc = &event->hw;
-        int idx = hwc->idx;
+        int idx;
+        int err = 0;
 
+        perf_pmu_disable(event->pmu);
 
-        WARN_ON(idx < 0 || idx >= mipspmu->num_counters);
+        /* To look for a free counter for this event. */
+        idx = mipspmu->alloc_counter(cpuc, hwc);
+        if (idx < 0) {
+                err = idx;
+                goto out;
+        }
 
-        /* We are working on a local event. */
+        /*
+         * If there is an event in the counter we are going to use then
+         * make sure it is disabled.
+         */
+        event->hw.idx = idx;
         mipspmu->disable_event(idx);
+        cpuc->events[idx] = event;
 
-        barrier();
-
-        mipspmu_event_update(event, hwc, idx);
-        cpuc->events[idx] = NULL;
-        clear_bit(idx, cpuc->used_mask);
+        hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+        if (flags & PERF_EF_START)
+                mipspmu_start(event, PERF_EF_RELOAD);
 
+        /* Propagate our changes to the userspace mapping. */
         perf_event_update_userpage(event);
+
+out:
+        perf_pmu_enable(event->pmu);
+        return err;
 }
 
-static void mipspmu_unthrottle(struct perf_event *event)
+static void mipspmu_del(struct perf_event *event, int flags)
 {
+        struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
         struct hw_perf_event *hwc = &event->hw;
+        int idx = hwc->idx;
 
-        mipspmu->enable_event(hwc, hwc->idx);
+        WARN_ON(idx < 0 || idx >= mipspmu->num_counters);
+
+        mipspmu_stop(event, PERF_EF_UPDATE);
+        cpuc->events[idx] = NULL;
+        clear_bit(idx, cpuc->used_mask);
+
+        perf_event_update_userpage(event);
 }
 
 static void mipspmu_read(struct perf_event *event)
@@ -270,12 +293,17 @@ static void mipspmu_read(struct perf_event *event)
         mipspmu_event_update(event, hwc, hwc->idx);
 }
 
-static struct pmu pmu = {
-        .enable         = mipspmu_enable,
-        .disable        = mipspmu_disable,
-        .unthrottle     = mipspmu_unthrottle,
-        .read           = mipspmu_read,
-};
+static void mipspmu_enable(struct pmu *pmu)
+{
+        if (mipspmu)
+                mipspmu->start();
+}
+
+static void mipspmu_disable(struct pmu *pmu)
+{
+        if (mipspmu)
+                mipspmu->stop();
+}
 
 static atomic_t active_events = ATOMIC_INIT(0);
 static DEFINE_MUTEX(pmu_reserve_mutex);
@@ -318,6 +346,82 @@ static void mipspmu_free_irq(void)
                 perf_irq = save_perf_irq;
 }
 
+/*
+ * mipsxx/rm9000/loongson2 have different performance counters, they have
+ * specific low-level init routines.
+ */
+static void reset_counters(void *arg);
+static int __hw_perf_event_init(struct perf_event *event);
+
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+        if (atomic_dec_and_mutex_lock(&active_events,
+                                &pmu_reserve_mutex)) {
+                /*
+                 * We must not call the destroy function with interrupts
+                 * disabled.
+                 */
+                on_each_cpu(reset_counters,
+                        (void *)(long)mipspmu->num_counters, 1);
+                mipspmu_free_irq();
+                mutex_unlock(&pmu_reserve_mutex);
+        }
+}
+
+static int mipspmu_event_init(struct perf_event *event)
+{
+        int err = 0;
+
+        switch (event->attr.type) {
+        case PERF_TYPE_RAW:
+        case PERF_TYPE_HARDWARE:
+        case PERF_TYPE_HW_CACHE:
+                break;
+
+        default:
+                return -ENOENT;
+        }
+
+        if (!mipspmu || event->cpu >= nr_cpumask_bits ||
+                (event->cpu >= 0 && !cpu_online(event->cpu)))
+                return -ENODEV;
+
+        if (!atomic_inc_not_zero(&active_events)) {
+                if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {
+                        atomic_dec(&active_events);
+                        return -ENOSPC;
+                }
+
+                mutex_lock(&pmu_reserve_mutex);
+                if (atomic_read(&active_events) == 0)
+                        err = mipspmu_get_irq();
+
+                if (!err)
+                        atomic_inc(&active_events);
+                mutex_unlock(&pmu_reserve_mutex);
+        }
+
+        if (err)
+                return err;
+
+        err = __hw_perf_event_init(event);
+        if (err)
+                hw_perf_event_destroy(event);
+
+        return err;
+}
+
+static struct pmu pmu = {
+        .pmu_enable     = mipspmu_enable,
+        .pmu_disable    = mipspmu_disable,
+        .event_init     = mipspmu_event_init,
+        .add            = mipspmu_add,
+        .del            = mipspmu_del,
+        .start          = mipspmu_start,
+        .stop           = mipspmu_stop,
+        .read           = mipspmu_read,
+};
+
 static inline unsigned int
 mipspmu_perf_event_encode(const struct mips_perf_event *pev)
 {
@@ -409,73 +513,6 @@ static int validate_group(struct perf_event *event)
         return 0;
 }
 
-/*
- * mipsxx/rm9000/loongson2 have different performance counters, they have
- * specific low-level init routines.
- */
-static void reset_counters(void *arg);
-static int __hw_perf_event_init(struct perf_event *event);
-
-static void hw_perf_event_destroy(struct perf_event *event)
-{
-        if (atomic_dec_and_mutex_lock(&active_events,
-                                &pmu_reserve_mutex)) {
-                /*
-                 * We must not call the destroy function with interrupts
-                 * disabled.
-                 */
-                on_each_cpu(reset_counters,
-                        (void *)(long)mipspmu->num_counters, 1);
-                mipspmu_free_irq();
-                mutex_unlock(&pmu_reserve_mutex);
-        }
-}
-
-const struct pmu *hw_perf_event_init(struct perf_event *event)
-{
-        int err = 0;
-
-        if (!mipspmu || event->cpu >= nr_cpumask_bits ||
-                (event->cpu >= 0 && !cpu_online(event->cpu)))
-                return ERR_PTR(-ENODEV);
-
-        if (!atomic_inc_not_zero(&active_events)) {
-                if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {
-                        atomic_dec(&active_events);
-                        return ERR_PTR(-ENOSPC);
-                }
-
-                mutex_lock(&pmu_reserve_mutex);
-                if (atomic_read(&active_events) == 0)
-                        err = mipspmu_get_irq();
-
-                if (!err)
-                        atomic_inc(&active_events);
-                mutex_unlock(&pmu_reserve_mutex);
-        }
-
-        if (err)
-                return ERR_PTR(err);
-
-        err = __hw_perf_event_init(event);
-        if (err)
-                hw_perf_event_destroy(event);
-
-        return err ? ERR_PTR(err) : &pmu;
-}
-
-void hw_perf_enable(void)
-{
-        if (mipspmu)
-                mipspmu->start();
-}
-
-void hw_perf_disable(void)
-{
-        if (mipspmu)
-                mipspmu->stop();
-}
-
 /* This is needed by specific irq handlers in perf_event_*.c */
 static void
 handle_associated_event(struct cpu_hw_events *cpuc,
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index d45ea37062bc..d9a7db78ed62 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -1045,6 +1045,8 @@ init_hw_perf_events(void)
                         "CPU, irq %d%s\n", mipspmu->name, counters, irq,
                         irq < 0 ? " (share with timer interrupt)" : "");
 
+        perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
+
         return 0;
 }
 early_initcall(init_hw_perf_events);