s390/pai_ext: Enable per-task counting event

The PMU for PAI NNPA counters enforces the following restriction:

 - No per-task context for PAI NNPA counters.

This restriction is removed. One or more per-task/system-wide counting
events can now be active at the same time while one system wide
sampling event is active.

Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index 5d00f77a64a5fffaf6a3745b03a532c36ba74ab1..20fc12dd9d0dd7a6a74c0c6c688a0b6fd4cc390b 100644 (file)
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -115,22 +115,36 @@ static void paiext_free(struct paiext_mapptr *mp)
 }
 
 /* Release the PMU if event is the last perf event */
-static void paiext_event_destroy(struct perf_event *event)
+static void paiext_event_destroy_cpu(struct perf_event *event, int cpu)
 {
-       struct paiext_mapptr *mp = per_cpu_ptr(paiext_root.mapptr, event->cpu);
+       struct paiext_mapptr *mp = per_cpu_ptr(paiext_root.mapptr, cpu);
        struct paiext_map *cpump = mp->mapptr;
 
        mutex_lock(&paiext_reserve_mutex);
        if (event->attr.sample_period)
                cpump->mode &= ~PAI_MODE_SAMPLING;
-       free_page(PAI_SAVE_AREA(event));
        if (refcount_dec_and_test(&cpump->refcnt))      /* Last reference gone */
                paiext_free(mp);
        paiext_root_free();
        mutex_unlock(&paiext_reserve_mutex);
-       debug_sprintf_event(paiext_dbg, 4, "%s cpu %d mapptr %p\n", __func__,
-                           event->cpu, mp->mapptr);
+}
+
+static void paiext_event_destroy(struct perf_event *event)
+{
+       int cpu;
+
+       free_page(PAI_SAVE_AREA(event));
+       if (event->cpu == -1) {
+               struct cpumask *mask = PAI_CPU_MASK(event);
 
+               for_each_cpu(cpu, mask)
+                       paiext_event_destroy_cpu(event, cpu);
+               kfree(mask);
+       } else {
+               paiext_event_destroy_cpu(event, event->cpu);
+       }
+       debug_sprintf_event(paiext_dbg, 4, "%s cpu %d\n", __func__,
+                           event->cpu);
 }
 
 /* Used to avoid races in checking concurrent access of counting and
@@ -147,19 +161,18 @@ static void paiext_event_destroy(struct perf_event *event)
  *
  * Allocate the memory for the event.
  */
-static int paiext_alloc(struct perf_event_attr *a, struct perf_event *event)
+static int paiext_alloc_cpu(struct perf_event_attr *a, int cpu)
 {
        struct paiext_mapptr *mp;
        struct paiext_map *cpump;
        int rc;
 
        mutex_lock(&paiext_reserve_mutex);
-
        rc = paiext_root_alloc();
        if (rc)
                goto unlock;
 
-       mp = per_cpu_ptr(paiext_root.mapptr, event->cpu);
+       mp = per_cpu_ptr(paiext_root.mapptr, cpu);
        cpump = mp->mapptr;
        if (!cpump) {                   /* Paiext_map allocated? */
                rc = -ENOMEM;
@@ -217,6 +230,40 @@ unlock:
        return rc;
 }
 
+static int paiext_alloc(struct perf_event *event)
+{
+       struct cpumask *maskptr;
+       int cpu, rc = -ENOMEM;
+
+       maskptr = kzalloc(sizeof(*maskptr), GFP_KERNEL);
+       if (!maskptr)
+               goto out;
+
+       for_each_online_cpu(cpu) {
+               rc = paiext_alloc_cpu(&event->attr, cpu);
+               if (rc) {
+                       for_each_cpu(cpu, maskptr)
+                               paiext_event_destroy_cpu(event, cpu);
+                       kfree(maskptr);
+                       goto out;
+               }
+               cpumask_set_cpu(cpu, maskptr);
+       }
+
+       /*
+        * On error all cpumask are freed and all events have been destroyed.
+        * Save of which CPUs data structures have been allocated for.
+        * Release them in paicrypt_event_destroy call back function
+        * for this event.
+        */
+       PAI_CPU_MASK(event) = maskptr;
+       rc = 0;
+out:
+       debug_sprintf_event(paiext_dbg, 5, "%s cpu %u rc %d\n", __func__,
+                           cpu, rc);
+       return rc;
+}
+
 /* The PAI extension 1 control block supports up to 128 entries. Return
  * the index within PAIE1_CB given the event number. Also validate event
  * number.
@@ -246,8 +293,9 @@ static int paiext_event_init(struct perf_event *event)
        rc = paiext_event_valid(event);
        if (rc)
                return rc;
-       /* Allow only CPU wide operation, no process context for now. */
-       if ((event->attach_state & PERF_ATTACH_TASK) || event->cpu == -1)
+       /* Allow only CPU wide operation for sampling */
+       if (a->sample_period &&
+           ((event->attach_state & PERF_ATTACH_TASK) || event->cpu == -1))
                return -ENOENT;
        /* Allow only event NNPA_ALL for sampling. */
        if (a->sample_period && a->config != PAI_NNPA_BASE)
@@ -262,7 +310,10 @@ static int paiext_event_init(struct perf_event *event)
                        return -ENOMEM;
        }
 
-       rc = paiext_alloc(a, event);
+       if (event->cpu >= 0)
+               rc = paiext_alloc_cpu(a, event->cpu);
+       else
+               rc = paiext_alloc(event);
        if (rc) {
                free_page(PAI_SAVE_AREA(event));
                return rc;
@@ -352,8 +403,6 @@ static int paiext_add(struct perf_event *event, int flags)
                pcb->acc = virt_to_phys(cpump->area) | 0x1;
                /* Enable CPU instruction lookup for PAIE1 control block */
                local_ctl_set_bit(0, CR0_PAI_EXTENSION_BIT);
-               debug_sprintf_event(paiext_dbg, 4, "%s 1508 %llx acc %llx\n",
-                                   __func__, S390_lowcore.aicd, pcb->acc);
        }
        if (flags & PERF_EF_START)
                paiext_start(event, PERF_EF_RELOAD);
@@ -387,8 +436,6 @@ static void paiext_del(struct perf_event *event, int flags)
                local_ctl_clear_bit(0, CR0_PAI_EXTENSION_BIT);
                pcb->acc = 0;
                S390_lowcore.aicd = 0;
-               debug_sprintf_event(paiext_dbg, 4, "%s 1508 %llx acc %llx\n",
-                                   __func__, S390_lowcore.aicd, pcb->acc);
        }
 }
 
@@ -544,7 +591,7 @@ static const struct attribute_group *paiext_attr_groups[] = {
 
 /* Performance monitoring unit for mapped counters */
 static struct pmu paiext = {
-       .task_ctx_nr  = perf_invalid_context,
+       .task_ctx_nr  = perf_hw_context,
        .event_init   = paiext_event_init,
        .add          = paiext_add,
        .del          = paiext_del,