perf, bpf: Add BPF support to all perf_event types

Allow BPF_PROG_TYPE_PERF_EVENT program types to attach to all
perf_event types, including HW_CACHE, RAW, and dynamic pmu events.
Only tracepoint/kprobe events are treated differently which require
BPF_PROG_TYPE_TRACEPOINT/BPF_PROG_TYPE_KPROBE program types accordingly.

Also add support for reading all event counters using
bpf_perf_event_read() helper.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 48 insertions, 56 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 24a635887f28..8fc5f0fada5e 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -896,7 +896,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr,
                                 void *context);
 extern void perf_pmu_migrate_context(struct pmu *pmu,
                                 int src_cpu, int dst_cpu);
-extern u64 perf_event_read_local(struct perf_event *event);
+int perf_event_read_local(struct perf_event *event, u64 *value);
 extern u64 perf_event_read_value(struct perf_event *event,
                                  u64 *enabled, u64 *running);
 
@@ -1301,7 +1301,10 @@ static inline const struct perf_event_attr *perf_event_attrs(struct perf_event *
 {
         return ERR_PTR(-EINVAL);
 }
-static inline u64 perf_event_read_local(struct perf_event *event)       { return -EINVAL; }
+static inline int perf_event_read_local(struct perf_event *event, u64 *value)
+{
+        return -EINVAL;
+}
 static inline void perf_event_print_debug(void)                         { }
 static inline int perf_event_task_disable(void)                         { return -EINVAL; }
 static inline int perf_event_task_enable(void)                          { return -EINVAL; }
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 172dc8ee0e3b..ecb43542246e 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -452,38 +452,24 @@ static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
 static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
                                          struct file *map_file, int fd)
 {
-        const struct perf_event_attr *attr;
         struct bpf_event_entry *ee;
         struct perf_event *event;
         struct file *perf_file;
+        u64 value;
 
         perf_file = perf_event_get(fd);
         if (IS_ERR(perf_file))
                 return perf_file;
 
+        ee = ERR_PTR(-EOPNOTSUPP);
         event = perf_file->private_data;
-        ee = ERR_PTR(-EINVAL);
-
-        attr = perf_event_attrs(event);
-        if (IS_ERR(attr) || attr->inherit)
+        if (perf_event_read_local(event, &value) == -EOPNOTSUPP)
                 goto err_out;
 
-        switch (attr->type) {
-        case PERF_TYPE_SOFTWARE:
-                if (attr->config != PERF_COUNT_SW_BPF_OUTPUT)
-                        goto err_out;
-                /* fall-through */
-        case PERF_TYPE_RAW:
-        case PERF_TYPE_HARDWARE:
-                ee = bpf_event_entry_gen(perf_file, map_file);
-                if (ee)
-                        return ee;
-                ee = ERR_PTR(-ENOMEM);
-                /* fall-through */
-        default:
-                break;
-        }
-
+        ee = bpf_event_entry_gen(perf_file, map_file);
+        if (ee)
+                return ee;
+        ee = ERR_PTR(-ENOMEM);
 err_out:
         fput(perf_file);
         return ee;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6e75a5c9412d..51e40e4876c0 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3636,10 +3636,10 @@ 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 +3647,37 @@ 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 +3687,11 @@ 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)
@@ -8037,12 +8050,8 @@ 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;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 460a031c77e5..08eb072430b9 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -234,7 +234,8 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
         unsigned int cpu = smp_processor_id();
         u64 index = flags & BPF_F_INDEX_MASK;
         struct bpf_event_entry *ee;
-        struct perf_event *event;
+        u64 value = 0;
+        int err;
 
         if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
                 return -EINVAL;
@@ -247,21 +248,14 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
         if (!ee)
                 return -ENOENT;
 
-        event = ee->event;
-        if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
-                     event->attr.type != PERF_TYPE_RAW))
-                return -EINVAL;
-
-        /* make sure event is local and doesn't have pmu::count */
-        if (unlikely(event->oncpu != cpu || event->pmu->count))
-                return -EINVAL;
-
+        err = perf_event_read_local(ee->event, &value);
         /*
-         * we don't know if the function is run successfully by the
-         * return value. It can be judged in other places, such as
-         * eBPF programs.
+         * this api is ugly since we miss [-22..-2] range of valid
+         * counter values, but that's uapi
          */
-        return perf_event_read_local(event);
+        if (err)
+                return err;
+        return value;
 }
 
 static const struct bpf_func_proto bpf_perf_event_read_proto = {