1 files changed, 187 insertions, 80 deletions

diff --git a/arch/s390/kernel/perf_pai.c b/arch/s390/kernel/perf_pai.c
index 810f5b6c5e01..013c3dae21ec 100644
--- a/arch/s390/kernel/perf_pai.c
+++ b/arch/s390/kernel/perf_pai.c
@@ -67,6 +67,7 @@ struct pai_mapptr {
 
 static struct pai_root {		/* Anchor to per CPU data */
 	refcount_t refcnt;		/* Overall active events */
+	atomic_t tskctx;		/* Overall per-task events */
 	struct pai_mapptr __percpu *mapptr;
 } pai_root[PAI_PMU_MAX];
 
@@ -93,14 +94,15 @@ struct pai_pmu {			/* Define PAI PMU characteristics */
 static struct pai_pmu pai_pmu[];	/* Forward declaration */
 
 /* Free per CPU data when the last event is removed. */
-static void pai_root_free(int idx)
+static void pai_root_free(int idx, int tasks)
 {
-	if (refcount_dec_and_test(&pai_root[idx].refcnt)) {
+	if (refcount_sub_and_test(tasks, &pai_root[idx].refcnt)) {
 		free_percpu(pai_root[idx].mapptr);
 		pai_root[idx].mapptr = NULL;
 	}
-	debug_sprintf_event(paidbg, 5, "%s root[%d].refcount %d\n", __func__,
-			    idx, refcount_read(&pai_root[idx].refcnt));
+	debug_sprintf_event(paidbg, 5, "%s root[%d].refcount %d tskctx %d\n",
+			    __func__, idx, refcount_read(&pai_root[idx].refcnt),
+			    atomic_read(&pai_root[idx].tskctx));
 }
 
 /*
@@ -137,40 +139,54 @@ static void pai_free(struct pai_mapptr *mp)
 	mp->mapptr = NULL;
 }
 
-/* Adjust usage counters and remove allocated memory when all users are
- * gone.
- */
-static void pai_event_destroy_cpu(struct perf_event *event, int cpu)
+/* Called under mutex_lock */
+static void pai_event_destroy_cpu(int idx, int cpu, bool hotplug)
 {
-	int idx = PAI_PMU_IDX(event);
-	struct pai_mapptr *mp = per_cpu_ptr(pai_root[idx].mapptr, cpu);
-	struct pai_map *cpump = mp->mapptr;
+	struct pai_mapptr *mp;
+	struct pai_map *cpump;
+	int tasks = 1;
 
-	mutex_lock(&pai_reserve_mutex);
-	debug_sprintf_event(paidbg, 5, "%s event %#llx idx %d cpu %d users %d "
-			    "refcnt %u\n", __func__, event->attr.config, idx,
-			    event->cpu, cpump->active_events,
-			    refcount_read(&cpump->refcnt));
-	if (refcount_dec_and_test(&cpump->refcnt))
+	/* Check reference count and return when all gone.
+	 * 1. An event is installed on online CPU X.
+	 * 2. CPU x is offlined and the per-CPU data is removed.
+	 * 3. Event is destroyed via close system call.
+	 */
+	if (!refcount_read(&pai_root[idx].refcnt))
+		return;			/* No events at all */
+	mp = per_cpu_ptr(pai_root[idx].mapptr, cpu);
+	if (!mp || !mp->mapptr)		/* No events on that CPU */
+		return;
+
+	/* When hotplug is true, invocation is from CPU hotplug callback.
+	 * Delete per-CPU resource and adjust refcnt when per-task events
+	 * are currently active. This can be more than one.
+	 * In this case adjust counters.
+	 */
+	if (hotplug)
+		tasks = atomic_read(&pai_root[idx].tskctx);
+
+	cpump = mp->mapptr;
+	if (refcount_sub_and_test(tasks, &cpump->refcnt))
 		pai_free(mp);
-	pai_root_free(idx);
-	mutex_unlock(&pai_reserve_mutex);
+	pai_root_free(idx, tasks);
 }
 
 static void pai_event_destroy(struct perf_event *event)
 {
-	int cpu;
+	int cpu = 0, idx = PAI_PMU_IDX(event);
 
 	free_page(PAI_SAVE_AREA(event));
+	cpus_read_lock();
+	mutex_lock(&pai_reserve_mutex);
 	if (event->cpu == -1) {
-		struct cpumask *mask = PAI_CPU_MASK(event);
-
-		for_each_cpu(cpu, mask)
-			pai_event_destroy_cpu(event, cpu);
-		kfree(mask);
+		atomic_dec(&pai_root[idx].tskctx);
+		for_each_online_cpu(cpu)
+			pai_event_destroy_cpu(idx, cpu, false);
 	} else {
-		pai_event_destroy_cpu(event, event->cpu);
+		pai_event_destroy_cpu(idx, event->cpu, false);
 	}
+	mutex_unlock(&pai_reserve_mutex);
+	cpus_read_unlock();
 }
 
 static void paicrypt_event_destroy(struct perf_event *event)
@@ -186,6 +202,13 @@ static u64 pai_getctr(unsigned long *page, int nr, unsigned long offset)
 	return page[nr];
 }
 
+static void pai_setctr(unsigned long *page, int nr, unsigned long offset, u64 v)
+{
+	if (offset)
+		nr += offset / sizeof(*page);
+	page[nr] = v;
+}
+
 /* Read the counter values. Return value from location in CMP. For base
  * event xxx_ALL sum up all events. Returns counter value.
  */
@@ -227,32 +250,37 @@ static u64 paicrypt_getall(struct perf_event *event)
 	return sum;
 }
 
-/* Check concurrent access of counting and sampling for crypto events.
- * This function is called in process context and it is save to block.
- * When the event initialization functions fails, no other call back will
- * be invoked.
- *
- * Allocate the memory for the event.
- */
-static int pai_alloc_cpu(struct perf_event *event, int cpu)
+/* Called under mutex_lock */
+static int pai_alloc_cpu(int idx, int cpu, bool hotplug)
 {
-	int rc, idx = PAI_PMU_IDX(event);
 	struct pai_map *cpump = NULL;
 	bool need_paiext_cb = false;
 	struct pai_mapptr *mp;
+	int tasks = 1, rc = 0;
+
+	/* When hotplug is true, invocation is from CPU hotplug callback.
+	 * Allocate per-CPU resource when per-task events are currently active.
+	 * This can be more than one. In this case adjust all reference
+	 * counters. Otherwise return, this ensures memory is only allocated
+	 * when needed.
+	 */
+	if (hotplug) {
+		tasks = atomic_read(&pai_root[idx].tskctx);
+		if (!tasks)
+			goto out;
+	}
 
-	mutex_lock(&pai_reserve_mutex);
 	/* Allocate root node */
 	rc = pai_root_alloc(idx);
 	if (rc)
-		goto unlock;
+		goto out;
 
 	/* Allocate node for this event */
 	mp = per_cpu_ptr(pai_root[idx].mapptr, cpu);
 	cpump = mp->mapptr;
 	if (!cpump) {			/* Paicrypt_map allocated? */
 		rc = -ENOMEM;
-		cpump = kzalloc(sizeof(*cpump), GFP_KERNEL);
+		cpump = kzalloc_obj(*cpump);
 		if (!cpump)
 			goto undo;
 		/* Allocate memory for counter page and counter extraction.
@@ -281,63 +309,75 @@ static int pai_alloc_cpu(struct perf_event *event, int cpu)
 			cpump->paiext_cb = kzalloc(PAIE1_CB_SZ, GFP_KERNEL);
 			need_paiext_cb = true;
 		}
-		cpump->save = kvmalloc_array(pai_pmu[idx].num_avail + 1,
-					     sizeof(struct pai_userdata),
-					     GFP_KERNEL);
+		cpump->save = kvmalloc_objs(struct pai_userdata,
+					    pai_pmu[idx].num_avail + 1);
 		if (!cpump->area || !cpump->save ||
 		    (need_paiext_cb && !cpump->paiext_cb)) {
 			pai_free(mp);
 			goto undo;
 		}
 		INIT_LIST_HEAD(&cpump->syswide_list);
-		refcount_set(&cpump->refcnt, 1);
+		refcount_set(&cpump->refcnt, tasks);
 		rc = 0;
 	} else {
-		refcount_inc(&cpump->refcnt);
+		refcount_add(tasks, &cpump->refcnt);
 	}
+	/* If tasks is greater than 1, we are called from CPU hotplug path
+	 * and need to adjust the pai_root[idx].refcnt by the number of
+	 * per-process events. Function pai_root_alloc(idx) already
+	 * incremented by one. Adjust for the rest.
+	 */
+	if (tasks > 1)
+		refcount_add(tasks - 1, &pai_root[idx].refcnt);
 
 undo:
 	if (rc) {
 		/* Error in allocation of event, decrement anchor. Since
 		 * the event in not created, its destroy() function is never
 		 * invoked. Adjust the reference counter for the anchor.
+		 * The failure happened in the case of variable
+		 * cpump == NULL branch above. The pai_root[XXX].refcnt has
+		 * been incremented by one. Then the per-CPU allocation
+		 * failed, so decrement it by one, regardless of tasks.
 		 */
-		pai_root_free(idx);
+		pai_root_free(idx, 1);
 	}
-unlock:
-	mutex_unlock(&pai_reserve_mutex);
+out:
 	/* If rc is non-zero, no increment of counter/sampler was done. */
 	return rc;
 }
 
+/* Check concurrent access of counting and sampling for PAI events.
+ * This function is called in process context and it is safe to block.
+ * When the event initialization functions fails, no other call back will
+ * be invoked.
+ * Called under mutex_lock.
+ */
 static int pai_alloc(struct perf_event *event)
 {
+	int idx = PAI_PMU_IDX(event);
 	struct cpumask *maskptr;
 	int cpu, rc = -ENOMEM;
 
-	maskptr = kzalloc(sizeof(*maskptr), GFP_KERNEL);
+	maskptr = kzalloc_obj(*maskptr);
 	if (!maskptr)
 		goto out;
 
 	for_each_online_cpu(cpu) {
-		rc = pai_alloc_cpu(event, cpu);
+		rc = pai_alloc_cpu(idx, cpu, false);
 		if (rc) {
 			for_each_cpu(cpu, maskptr)
-				pai_event_destroy_cpu(event, cpu);
-			kfree(maskptr);
-			goto out;
+				pai_event_destroy_cpu(idx, cpu, false);
+			goto undo;
 		}
 		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 pai_event_destroy call back function
-	 * for this event.
-	 */
-	PAI_CPU_MASK(event) = maskptr;
 	rc = 0;
+	/* Trace per-task events for CPU hotplug. */
+	atomic_inc(&pai_root[idx].tskctx);
+undo:
+	kfree(maskptr);
 out:
 	return rc;
 }
@@ -385,10 +425,14 @@ static int pai_event_init(struct perf_event *event, int idx)
 		}
 	}
 
+	cpus_read_lock();
+	mutex_lock(&pai_reserve_mutex);
 	if (event->cpu >= 0)
-		rc = pai_alloc_cpu(event, event->cpu);
+		rc = pai_alloc_cpu(idx, event->cpu, false);
 	else
 		rc = pai_alloc(event);
+	mutex_unlock(&pai_reserve_mutex);
+	cpus_read_unlock();
 	if (rc) {
 		free_page(PAI_SAVE_AREA(event));
 		goto out;
@@ -458,6 +502,7 @@ static void pai_start(struct perf_event *event, int flags,
 			cpump->event = event;
 		}
 	}
+	event->hw.state &= ~PERF_HES_STOPPED;
 }
 
 static void paicrypt_start(struct perf_event *event, int flags)
@@ -504,6 +549,13 @@ static void pai_stop(struct perf_event *event, int flags)
 	struct pai_mapptr *mp = this_cpu_ptr(pai_root[idx].mapptr);
 	struct pai_map *cpump = mp->mapptr;
 
+	/* Cope with multiple invocations:
+	 *   1. perf_event_throttle() --> PMU->stop()
+	 *   2. task schedules out --> PMU->stop()
+	 * Check for event already stopped.
+	 */
+	if (event->hw.state & PERF_HES_STOPPED)
+		return;
 	if (!event->attr.sample_period) {	/* Counting */
 		pai_pmu[idx].pmu->read(event);
 	} else {				/* Sampling */
@@ -552,6 +604,8 @@ static void paicrypt_del(struct perf_event *event, int flags)
 /* Create raw data and save it in buffer. Calculate the delta for each
  * counter between this invocation and the last invocation.
  * Returns number of bytes copied.
+ * After reading from PAI counter page, save the read value to the old
+ * page to calculate PAI counter deltas.
  * Saves only entries with positive counter difference of the form
  * 2 bytes: Number of counter
  * 8 bytes: Value of counter
@@ -563,16 +617,22 @@ static size_t pai_copy(struct pai_userdata *userdata, unsigned long *page,
 	int i, outidx = 0;
 
 	for (i = 1; i <= pp->num_avail; i++) {
-		u64 val = 0, val_old = 0;
+		u64 val = 0, val_old = 0, val_k = 0, val_old_k = 0;
 
 		if (!exclude_kernel) {
-			val += pai_getctr(page, i, pp->kernel_offset);
-			val_old += pai_getctr(page_old, i, pp->kernel_offset);
+			val_k = pai_getctr(page, i, pp->kernel_offset);
+			val_old_k = pai_getctr(page_old, i, pp->kernel_offset);
+			if (val_k != val_old_k)
+				pai_setctr(page_old, i, pp->kernel_offset, val_k);
 		}
 		if (!exclude_user) {
-			val += pai_getctr(page, i, 0);
-			val_old += pai_getctr(page_old, i, 0);
+			val = pai_getctr(page, i, 0);
+			val_old = pai_getctr(page_old, i, 0);
+			if (val != val_old)
+				pai_setctr(page_old, i, 0, val);
 		}
+		val += val_k;
+		val_old += val_old_k;
 		if (val >= val_old)
 			val -= val_old;
 		else
@@ -603,8 +663,6 @@ static size_t pai_copy(struct pai_userdata *userdata, unsigned long *page,
 static int pai_push_sample(size_t rawsize, struct pai_map *cpump,
 			   struct perf_event *event)
 {
-	int idx = PAI_PMU_IDX(event);
-	struct pai_pmu *pp = &pai_pmu[idx];
 	struct perf_sample_data data;
 	struct perf_raw_record raw;
 	struct pt_regs regs;
@@ -635,8 +693,6 @@ static int pai_push_sample(size_t rawsize, struct pai_map *cpump,
 
 	overflow = perf_event_overflow(event, &data, &regs);
 	perf_event_update_userpage(event);
-	/* Save crypto counter lowcore page after reading event data. */
-	memcpy((void *)PAI_SAVE_AREA(event), cpump->area, pp->area_size);
 	return overflow;
 }
 
@@ -652,7 +708,7 @@ static void pai_have_sample(struct perf_event *event, struct pai_map *cpump)
 	rawsize = pai_copy(cpump->save, cpump->area, pp,
 			   (unsigned long *)PAI_SAVE_AREA(event),
 			   event->attr.exclude_user,
-			   event->attr.exclude_kernel);
+			   !pp->kernel_offset ? true : event->attr.exclude_kernel);
 	if (rawsize)			/* No incremented counters */
 		pai_push_sample(rawsize, cpump, event);
 }
@@ -662,9 +718,9 @@ static void pai_have_samples(int idx)
 {
 	struct pai_mapptr *mp = this_cpu_ptr(pai_root[idx].mapptr);
 	struct pai_map *cpump = mp->mapptr;
-	struct perf_event *event;
+	struct perf_event *event, *e2;
 
-	list_for_each_entry(event, &cpump->syswide_list, hw.tp_list)
+	list_for_each_entry_safe(event, e2, &cpump->syswide_list, hw.tp_list)
 		pai_have_sample(event, cpump);
 }
 
@@ -681,6 +737,17 @@ static void paicrypt_sched_task(struct perf_event_pmu_context *pmu_ctx,
 		pai_have_samples(PAI_PMU_CRYPTO);
 }
 
+/* Prevent ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call.
+ * It sets perf_event::event_limit to a positive value and causes
+ * perf_event_overflow() to invoke pai_stop() call back function when
+ * perf_event::event_limit hits zero. This is not supported because the
+ * sample events CRYPTO_ALL and NNPA_ALL are always taken at schedule out
+ * of a task.
+ */
+static int pai_check_period(struct perf_event *event, u64 value)
+{
+	return -EINVAL;
+}
 /* ============================= paiext ====================================*/
 
 static void paiext_event_destroy(struct perf_event *event)
@@ -794,6 +861,7 @@ static struct pmu paicrypt = {
 	.stop	      = paicrypt_stop,
 	.read	      = paicrypt_read,
 	.sched_task   = paicrypt_sched_task,
+	.check_period = pai_check_period,
 	.attr_groups  = paicrypt_attr_groups
 };
 
@@ -1005,6 +1073,7 @@ static struct pmu paiext = {
 	.stop	      = paiext_stop,
 	.read	      = paiext_read,
 	.sched_task   = paiext_sched_task,
+	.check_period = pai_check_period,
 	.attr_groups  = paiext_attr_groups,
 };
 
@@ -1070,7 +1139,7 @@ static struct attribute * __init attr_event_init_one(int num,
 {
 	struct perf_pmu_events_attr *pa;
 
-	pa = kzalloc(sizeof(*pa), GFP_KERNEL);
+	pa = kzalloc_obj(*pa);
 	if (!pa)
 		return NULL;
 
@@ -1089,7 +1158,7 @@ static struct attribute ** __init attr_event_init(struct pai_pmu *p)
 	struct attribute **attrs;
 	unsigned int i;
 
-	attrs = kmalloc_array(min_attr + 1, sizeof(*attrs), GFP_KERNEL | __GFP_ZERO);
+	attrs = kmalloc_objs(*attrs, min_attr + 1, GFP_KERNEL | __GFP_ZERO);
 	if (!attrs)
 		goto out;
 	for (i = 0; i < min_attr; i++) {
@@ -1208,23 +1277,61 @@ static int __init paipmu_setup(void)
 	return install_ok;
 }
 
+static int pai_online_cpu(unsigned int cpu)
+{
+	int rc;
+
+	mutex_lock(&pai_reserve_mutex);
+	rc = pai_alloc_cpu(PAI_PMU_CRYPTO, cpu, true);
+	if (rc)
+		goto out;
+	rc = pai_alloc_cpu(PAI_PMU_EXT, cpu, true);
+	if (rc)
+		pai_event_destroy_cpu(PAI_PMU_CRYPTO, cpu, true);
+out:
+	mutex_unlock(&pai_reserve_mutex);
+	return rc;
+}
+
+static int pai_offline_cpu(unsigned int cpu)
+{
+	mutex_lock(&pai_reserve_mutex);
+	pai_event_destroy_cpu(PAI_PMU_CRYPTO, cpu, true);
+	pai_event_destroy_cpu(PAI_PMU_EXT, cpu, true);
+	mutex_unlock(&pai_reserve_mutex);
+	return 0;
+}
+
 static int __init pai_init(void)
 {
+	int state, rc;
+
 	/* Setup s390dbf facility */
-	paidbg = debug_register("pai", 32, 256, 128);
+	paidbg = debug_register("pai", 1, 1, 128);
 	if (!paidbg) {
 		pr_err("Registration of s390dbf pai failed\n");
 		return -ENOMEM;
 	}
 	debug_register_view(paidbg, &debug_sprintf_view);
 
-	if (!paipmu_setup()) {
-		/* No PMU registration, no need for debug buffer */
-		debug_unregister_view(paidbg, &debug_sprintf_view);
-		debug_unregister(paidbg);
-		return -ENODEV;
-	}
+	/* CPUHP_BP_PREPARE_DYN --> before CPU is brought online */
+	state = cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "perf/pai:prepare",
+				  pai_online_cpu, pai_offline_cpu);
+	rc = state < 0 ? state : 0;
+	if (rc < 0)
+		goto out_debug;
+
+	rc = -ENODEV;
+	if (!paipmu_setup())
+		goto out_cpuhp;
 	return 0;
+
+out_cpuhp:
+	cpuhp_remove_state(state);
+out_debug:
+	debug_unregister_view(paidbg, &debug_sprintf_view);
+	debug_unregister(paidbg);
+	return rc;
 }
 
 device_initcall(pai_init);