Madhavan Srinivasan [ma...@linux.vnet.ibm.com] wrote:
| From: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
| Subject: [PATCH v2 6/7]powerpc/powernv: generic nest pmu event functions
| 
| Add generic format attribute and set of generic nest pmu related
| event functions to be used by each nest pmu. Add code to register nest pmus.
| 
| Cc: Michael Ellerman <m...@ellerman.id.au>
| Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
| Cc: Paul Mackerras <pau...@samba.org>
| Cc: Anton Blanchard <an...@samba.org>
| Cc: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
| Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com>
| Cc: Stephane Eranian <eran...@google.com>
| Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
| ---
|  arch/powerpc/perf/nest-pmu.c | 109 
+++++++++++++++++++++++++++++++++++++++++++
|  1 file changed, 109 insertions(+)
| 
| diff --git a/arch/powerpc/perf/nest-pmu.c b/arch/powerpc/perf/nest-pmu.c
| index 8fad2d9..a662c14 100644
| --- a/arch/powerpc/perf/nest-pmu.c
| +++ b/arch/powerpc/perf/nest-pmu.c
| @@ -13,6 +13,108 @@
|  static struct perchip_nest_info p8_perchip_nest_info[P8_MAX_CHIP];
|  static struct nest_pmu *per_nest_pmu_arr[P8_MAX_NEST_PMUS];
| 
| +PMU_FORMAT_ATTR(event, "config:0-20");
| +struct attribute *p8_nest_format_attrs[] = {
| +     &format_attr_event.attr,
| +     NULL,
| +};
| +
| +struct attribute_group p8_nest_format_group = {
| +     .name = "format",
| +     .attrs = p8_nest_format_attrs,
| +};

Could this be included in previous/separate patch? That way,
this patch could focus on just registering the nest-pmu.

| +
| +static int p8_nest_event_init(struct perf_event *event)
| +{
| +     int chip_id;
| +
| +     if (event->attr.type != event->pmu->type)
| +             return -ENOENT;
| +
| +     /* Sampling not supported yet */
| +     if (event->hw.sample_period)
| +             return -EINVAL;
| +
| +     /* unsupported modes and filters */
| +     if (event->attr.exclude_user   ||
| +         event->attr.exclude_kernel ||
| +         event->attr.exclude_hv     ||
| +         event->attr.exclude_idle   ||
| +         event->attr.exclude_host   ||
| +         event->attr.exclude_guest)
| +             return -EINVAL;
| +
| +     if (event->cpu < 0)
| +             return -EINVAL;
| +
| +     chip_id = topology_physical_package_id(event->cpu);
| +     event->hw.event_base = event->attr.config +
| +                             p8_perchip_nest_info[chip_id].vbase;
| +
| +     return 0;
| +}
| +
| +static void p8_nest_read_counter(struct perf_event *event)
| +{
| +     u64 *addr;
| 

Define as uint64_t so we can eliminate one cast below? Would also
be consistent with p8_nest_perf_event_update().

| 
| +     u64 data = 0;
| +
| +     addr = (u64 *)event->hw.event_base;
| +     data = __be64_to_cpu((uint64_t)*addr);
| +     local64_set(&event->hw.prev_count, data);
| +}
| +
| +static void p8_nest_perf_event_update(struct perf_event *event)
| +{
| +     u64 counter_prev, counter_new, final_count;
| +     uint64_t *addr;
| +
| +     addr = (u64 *)event->hw.event_base;

uint64_t *?

| +     counter_prev = local64_read(&event->hw.prev_count);
| +     counter_new = __be64_to_cpu((uint64_t)*addr);

Redundant cast? addr is already uint64_t *?

| +     final_count = counter_new - counter_prev;
| +
| +     local64_set(&event->hw.prev_count, counter_new);
| +     local64_add(final_count, &event->count);
| +}
| +
| +static void p8_nest_event_start(struct perf_event *event, int flags)
| +{

Check PERF_EF_RELOAD before reloading?

| +     event->hw.state = 0;
| +     p8_nest_read_counter(event);
| +}
| +
| +static void p8_nest_event_stop(struct perf_event *event, int flags)
| +{

Check PERF_EF_UPDATE when stopping?

| +     p8_nest_perf_event_update(event);
| +}
| +
| +static int p8_nest_event_add(struct perf_event *event, int flags)
| +{

Check PERF_EF_START flags before starting the counter on an ->add()?

| +     p8_nest_event_start(event, flags);
| +     return 0;
| +}
| +
| +/*
| + * Populate pmu ops in the structure
| + */
| +static int update_pmu_ops(struct nest_pmu *pmu)
| +{
| +     if (!pmu)
| +             return -EINVAL;
| +
| +     pmu->pmu.task_ctx_nr = perf_invalid_context;
| +     pmu->pmu.event_init = p8_nest_event_init;
| +     pmu->pmu.add = p8_nest_event_add;
| +     pmu->pmu.del = p8_nest_event_stop;
| +     pmu->pmu.start = p8_nest_event_start;
| +     pmu->pmu.stop = p8_nest_event_stop;
| +     pmu->pmu.read = p8_nest_perf_event_update;
| +     pmu->pmu.attr_groups = pmu->attr_groups;
| +
| +     return 0;
| +}
| +
|  /*
|   * Populate event name and string in attribute
|   */
| @@ -106,6 +208,7 @@ static int nest_pmu_create(struct device_node *dev, int 
pmu_index)
|                       /* Save the name to register the PMU with it */
|                       sprintf(buf, "Nest_%s", (char *)pp->value);
|                       pmu_ptr->pmu.name = (char *)buf;
| +                     pmu_ptr->attr_groups[1] = &p8_nest_format_group;
|               }
| 
|               /* Skip these, we dont need it */
| @@ -179,6 +282,12 @@ static int nest_pmu_create(struct device_node *dev, int 
pmu_index)
|               (struct ppc64_nest_ima_events *)p8_events_arr,
|                                                       idx, pmu_ptr);
| 
| +     update_pmu_ops(pmu_ptr);
| +
| +     /* Register the pmu */
| +     perf_pmu_register(&pmu_ptr->pmu, pmu_ptr->pmu.name, -1);

There is a small chance that perf_pmu_register() can fail.

| +     printk(KERN_INFO "Nest PMU %s Registered\n", pmu_ptr->pmu.name);
| +
|       return 0;
|  }
| 
| -- 
| 1.9.1
| 

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