1 files changed, 131 insertions, 64 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6e75a5c..426c2ff 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -389,6 +389,7 @@ static atomic_t nr_switch_events __read_mostly;
 static LIST_HEAD(pmus);
 static DEFINE_MUTEX(pmus_lock);
 static struct srcu_struct pmus_srcu;
+static cpumask_var_t perf_online_mask;
 
 /*
  * perf event paranoia level:
@@ -925,11 +926,6 @@ static inline int is_cgroup_event(struct perf_event *event)
 	return 0;
 }
 
-static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
-{
-	return 0;
-}
-
 static inline void update_cgrp_time_from_event(struct perf_event *event)
 {
 }
@@ -1456,6 +1452,13 @@ static enum event_type_t get_event_type(struct perf_event *event)
 
 	lockdep_assert_held(&ctx->lock);
 
+	/*
+	 * It's 'group type', really, because if our group leader is
+	 * pinned, so are we.
+	 */
+	if (event->group_leader != event)
+		event = event->group_leader;
+
 	event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
 	if (!ctx->task)
 		event_type |= EVENT_CPU;
@@ -3636,10 +3639,10 @@ static inline u64 perf_event_count(struct perf_event *event)
  *     will not be local and we cannot read them atomically
  *   - must not have a pmu::count method
  */
-u64 perf_event_read_local(struct perf_event *event)
+int perf_event_read_local(struct perf_event *event, u64 *value)
 {
 	unsigned long flags;
-	u64 val;
+	int ret = 0;
 
 	/*
 	 * Disabling interrupts avoids all counter scheduling (context
@@ -3647,25 +3650,37 @@ u64 perf_event_read_local(struct perf_event *event)
 	 */
 	local_irq_save(flags);
 
-	/* If this is a per-task event, it must be for current */
-	WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
-		     event->hw.target != current);
-
-	/* If this is a per-CPU event, it must be for this CPU */
-	WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
-		     event->cpu != smp_processor_id());
-
 	/*
 	 * It must not be an event with inherit set, we cannot read
 	 * all child counters from atomic context.
 	 */
-	WARN_ON_ONCE(event->attr.inherit);
+	if (event->attr.inherit) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
 
 	/*
 	 * It must not have a pmu::count method, those are not
 	 * NMI safe.
 	 */
-	WARN_ON_ONCE(event->pmu->count);
+	if (event->pmu->count) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	/* If this is a per-task event, it must be for current */
+	if ((event->attach_state & PERF_ATTACH_TASK) &&
+	    event->hw.target != current) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If this is a per-CPU event, it must be for this CPU */
+	if (!(event->attach_state & PERF_ATTACH_TASK) &&
+	    event->cpu != smp_processor_id()) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	/*
 	 * If the event is currently on this CPU, its either a per-task event,
@@ -3675,10 +3690,11 @@ u64 perf_event_read_local(struct perf_event *event)
 	if (event->oncpu == smp_processor_id())
 		event->pmu->read(event);
 
-	val = local64_read(&event->count);
+	*value = local64_read(&event->count);
+out:
 	local_irq_restore(flags);
 
-	return val;
+	return ret;
 }
 
 static int perf_event_read(struct perf_event *event, bool group)
@@ -3812,14 +3828,6 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
 		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
 			return ERR_PTR(-EACCES);
 
-		/*
-		 * We could be clever and allow to attach a event to an
-		 * offline CPU and activate it when the CPU comes up, but
-		 * that's for later.
-		 */
-		if (!cpu_online(cpu))
-			return ERR_PTR(-ENODEV);
-
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
 		ctx = &cpuctx->ctx;
 		get_ctx(ctx);
@@ -4377,7 +4385,9 @@ EXPORT_SYMBOL_GPL(perf_event_read_value);
 static int __perf_read_group_add(struct perf_event *leader,
 					u64 read_format, u64 *values)
 {
+	struct perf_event_context *ctx = leader->ctx;
 	struct perf_event *sub;
+	unsigned long flags;
 	int n = 1; /* skip @nr */
 	int ret;
 
@@ -4407,12 +4417,15 @@ static int __perf_read_group_add(struct perf_event *leader,
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(leader);
 
+	raw_spin_lock_irqsave(&ctx->lock, flags);
+
 	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
 		values[n++] += perf_event_count(sub);
 		if (read_format & PERF_FORMAT_ID)
 			values[n++] = primary_event_id(sub);
 	}
 
+	raw_spin_unlock_irqrestore(&ctx->lock, flags);
 	return 0;
 }
 
@@ -5729,9 +5742,6 @@ static void perf_output_read_one(struct perf_output_handle *handle,
 	__output_copy(handle, values, n * sizeof(u64));
 }
 
-/*
- * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
- */
 static void perf_output_read_group(struct perf_output_handle *handle,
 			    struct perf_event *event,
 			    u64 enabled, u64 running)
@@ -5776,6 +5786,13 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
 				 PERF_FORMAT_TOTAL_TIME_RUNNING)
 
+/*
+ * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
+ *
+ * The problem is that its both hard and excessively expensive to iterate the
+ * child list, not to mention that its impossible to IPI the children running
+ * on another CPU, from interrupt/NMI context.
+ */
 static void perf_output_read(struct perf_output_handle *handle,
 			     struct perf_event *event)
 {
@@ -7703,7 +7720,8 @@ static int swevent_hlist_get_cpu(int cpu)
 	int err = 0;
 
 	mutex_lock(&swhash->hlist_mutex);
-	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
+	if (!swevent_hlist_deref(swhash) &&
+	    cpumask_test_cpu(cpu, perf_online_mask)) {
 		struct swevent_hlist *hlist;
 
 		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
@@ -7724,7 +7742,7 @@ static int swevent_hlist_get(void)
 {
 	int err, cpu, failed_cpu;
 
-	get_online_cpus();
+	mutex_lock(&pmus_lock);
 	for_each_possible_cpu(cpu) {
 		err = swevent_hlist_get_cpu(cpu);
 		if (err) {
@@ -7732,8 +7750,7 @@ static int swevent_hlist_get(void)
 			goto fail;
 		}
 	}
-	put_online_cpus();
-
+	mutex_unlock(&pmus_lock);
 	return 0;
 fail:
 	for_each_possible_cpu(cpu) {
@@ -7741,8 +7758,7 @@ fail:
 			break;
 		swevent_hlist_put_cpu(cpu);
 	}
-
-	put_online_cpus();
+	mutex_unlock(&pmus_lock);
 	return err;
 }
 
@@ -8037,12 +8053,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
 	bool is_kprobe, is_tracepoint;
 	struct bpf_prog *prog;
 
-	if (event->attr.type == PERF_TYPE_HARDWARE ||
-	    event->attr.type == PERF_TYPE_SOFTWARE)
-		return perf_event_set_bpf_handler(event, prog_fd);
-
 	if (event->attr.type != PERF_TYPE_TRACEPOINT)
-		return -EINVAL;
+		return perf_event_set_bpf_handler(event, prog_fd);
 
 	if (event->tp_event->prog)
 		return -EEXIST;
@@ -8920,7 +8932,7 @@ perf_event_mux_interval_ms_store(struct device *dev,
 	pmu->hrtimer_interval_ms = timer;
 
 	/* update all cpuctx for this PMU */
-	get_online_cpus();
+	cpus_read_lock();
 	for_each_online_cpu(cpu) {
 		struct perf_cpu_context *cpuctx;
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
@@ -8929,7 +8941,7 @@ perf_event_mux_interval_ms_store(struct device *dev,
 		cpu_function_call(cpu,
 			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
 	}
-	put_online_cpus();
+	cpus_read_unlock();
 	mutex_unlock(&mux_interval_mutex);
 
 	return count;
@@ -9059,6 +9071,7 @@ skip_type:
 		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
 		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
 		cpuctx->ctx.pmu = pmu;
+		cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
 
 		__perf_mux_hrtimer_init(cpuctx, cpu);
 	}
@@ -9172,7 +9185,7 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
 
 static struct pmu *perf_init_event(struct perf_event *event)
 {
-	struct pmu *pmu = NULL;
+	struct pmu *pmu;
 	int idx;
 	int ret;
 
@@ -9441,9 +9454,10 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	local64_set(&hwc->period_left, hwc->sample_period);
 
 	/*
-	 * we currently do not support PERF_FORMAT_GROUP on inherited events
+	 * We currently do not support PERF_SAMPLE_READ on inherited events.
+	 * See perf_output_read().
 	 */
-	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
+	if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
 		goto err_ns;
 
 	if (!has_branch_stack(event))
@@ -9456,9 +9470,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	}
 
 	pmu = perf_init_event(event);
-	if (!pmu)
-		goto err_ns;
-	else if (IS_ERR(pmu)) {
+	if (IS_ERR(pmu)) {
 		err = PTR_ERR(pmu);
 		goto err_ns;
 	}
@@ -9471,8 +9483,10 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 		event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
 						   sizeof(unsigned long),
 						   GFP_KERNEL);
-		if (!event->addr_filters_offs)
+		if (!event->addr_filters_offs) {
+			err = -ENOMEM;
 			goto err_per_task;
+		}
 
 		/* force hw sync on the address filters */
 		event->addr_filters_gen = 1;
@@ -9882,12 +9896,10 @@ SYSCALL_DEFINE5(perf_event_open,
 		goto err_task;
 	}
 
-	get_online_cpus();
-
 	if (task) {
 		err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
 		if (err)
-			goto err_cpus;
+			goto err_task;
 
 		/*
 		 * Reuse ptrace permission checks for now.
@@ -10073,6 +10085,23 @@ SYSCALL_DEFINE5(perf_event_open,
 		goto err_locked;
 	}
 
+	if (!task) {
+		/*
+		 * Check if the @cpu we're creating an event for is online.
+		 *
+		 * We use the perf_cpu_context::ctx::mutex to serialize against
+		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
+		 */
+		struct perf_cpu_context *cpuctx =
+			container_of(ctx, struct perf_cpu_context, ctx);
+
+		if (!cpuctx->online) {
+			err = -ENODEV;
+			goto err_locked;
+		}
+	}
+
+
 	/*
 	 * Must be under the same ctx::mutex as perf_install_in_context(),
 	 * because we need to serialize with concurrent event creation.
@@ -10162,8 +10191,6 @@ SYSCALL_DEFINE5(perf_event_open,
 		put_task_struct(task);
 	}
 
-	put_online_cpus();
-
 	mutex_lock(&current->perf_event_mutex);
 	list_add_tail(&event->owner_entry, &current->perf_event_list);
 	mutex_unlock(&current->perf_event_mutex);
@@ -10197,8 +10224,6 @@ err_alloc:
 err_cred:
 	if (task)
 		mutex_unlock(&task->signal->cred_guard_mutex);
-err_cpus:
-	put_online_cpus();
 err_task:
 	if (task)
 		put_task_struct(task);
@@ -10253,6 +10278,21 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 		goto err_unlock;
 	}
 
+	if (!task) {
+		/*
+		 * Check if the @cpu we're creating an event for is online.
+		 *
+		 * We use the perf_cpu_context::ctx::mutex to serialize against
+		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
+		 */
+		struct perf_cpu_context *cpuctx =
+			container_of(ctx, struct perf_cpu_context, ctx);
+		if (!cpuctx->online) {
+			err = -ENODEV;
+			goto err_unlock;
+		}
+	}
+
 	if (!exclusive_event_installable(event, ctx)) {
 		err = -EBUSY;
 		goto err_unlock;
@@ -10920,6 +10960,8 @@ static void __init perf_event_init_all_cpus(void)
 	struct swevent_htable *swhash;
 	int cpu;
 
+	zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
+
 	for_each_possible_cpu(cpu) {
 		swhash = &per_cpu(swevent_htable, cpu);
 		mutex_init(&swhash->hlist_mutex);
@@ -10935,7 +10977,7 @@ static void __init perf_event_init_all_cpus(void)
 	}
 }
 
-int perf_event_init_cpu(unsigned int cpu)
+void perf_swevent_init_cpu(unsigned int cpu)
 {
 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
 
@@ -10948,7 +10990,6 @@ int perf_event_init_cpu(unsigned int cpu)
 		rcu_assign_pointer(swhash->swevent_hlist, hlist);
 	}
 	mutex_unlock(&swhash->hlist_mutex);
-	return 0;
 }
 
 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
@@ -10966,19 +11007,22 @@ static void __perf_event_exit_context(void *__info)
 
 static void perf_event_exit_cpu_context(int cpu)
 {
+	struct perf_cpu_context *cpuctx;
 	struct perf_event_context *ctx;
 	struct pmu *pmu;
-	int idx;
 
-	idx = srcu_read_lock(&pmus_srcu);
-	list_for_each_entry_rcu(pmu, &pmus, entry) {
-		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
+	mutex_lock(&pmus_lock);
+	list_for_each_entry(pmu, &pmus, entry) {
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		ctx = &cpuctx->ctx;
 
 		mutex_lock(&ctx->mutex);
 		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
+		cpuctx->online = 0;
 		mutex_unlock(&ctx->mutex);
 	}
-	srcu_read_unlock(&pmus_srcu, idx);
+	cpumask_clear_cpu(cpu, perf_online_mask);
+	mutex_unlock(&pmus_lock);
 }
 #else
 
@@ -10986,6 +11030,29 @@ static void perf_event_exit_cpu_context(int cpu) { }
 
 #endif
 
+int perf_event_init_cpu(unsigned int cpu)
+{
+	struct perf_cpu_context *cpuctx;
+	struct perf_event_context *ctx;
+	struct pmu *pmu;
+
+	perf_swevent_init_cpu(cpu);
+
+	mutex_lock(&pmus_lock);
+	cpumask_set_cpu(cpu, perf_online_mask);
+	list_for_each_entry(pmu, &pmus, entry) {
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		ctx = &cpuctx->ctx;
+
+		mutex_lock(&ctx->mutex);
+		cpuctx->online = 1;
+		mutex_unlock(&ctx->mutex);
+	}
+	mutex_unlock(&pmus_lock);
+
+	return 0;
+}
+
 int perf_event_exit_cpu(unsigned int cpu)
 {
 	perf_event_exit_cpu_context(cpu);